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  • Electronic Resource  (12,039)
  • 2000-2004
  • 1995-1999  (12,039)
  • 1995  (12,039)
  • Chemistry  (11,922)
  • Apoptosis
  • evolution
  • 1
    Electronic Resource
    Electronic Resource
    Effects of tamoxifen on growth and apoptosis of estrogen-dependent and -independent human breast cancer cells (1995)
    Springer
    Annals of surgical oncology 2 (1995), S. 238-245 
    Details
    ISSN: 1534-4681
    Keywords: Apoptosis ; Tamoxifen ; Breast cancer ; MCF-7 cells ; MDA-231 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Apoptosis (“programmed cell death”) is an active process characterized by prominent nuclear changes and DNA cleavage, which distinguishes it from cellular necrosis. In this study we investigated whether tamoxifen (TAM) treatment of estrogen receptor ER(+) MCF-7 and ER(-) MDA-231 human breast cancer cells resulted in cytotoxicity and cellular changes typical of apoptosis. Methods: Cytotoxicity was measured using a tetrazolium assay. Cellular morphologic changes were observed using transmission electron microscopy. DNA cleavage was assessed using 1.6% agarose gel electrophoresis and was also quantitated biochemically. Results: Exposure of cells to TAM for 24 h resulted in dose- dependent cytotoxicity, and MCF-7 cells were somewhat more sensitive to TAM. TAM induced chromatin condensation around the nuclear periphery in both cell lines, changes typical of apoptosis. TAM-induced cytotoxicity correlated with dose-dependent DNA cleavage, which showed the characteristic “internucleosomal ladder.” DNA cleavage occurred at a slightly lower TAM dose and occurred somewhat sooner in MCF-7 cells. TAM-induced DNA cleavage in MCF-7 cells was inhibited by the protein synthesis inhibitor cycloheximide, the RNA synthesis inhibitor actinomycin D, and by 17β-estradiol. However, in MDA-231 cells, DNA cleavage was inhibited by cycloheximide, partially but not significantly inhibited by actinomycin D, and not inhibited by 17β-estradiol. Conclusions: TAM induces typical apoptosis in ER(+) or ER (-) human breast cancer cells. TAM induction of apoptosis in MCF-7 cells involves the estrogen receptor, and requires the synthesis of new protein and mRNA. TAM induction of apoptosis in MDA-231 cells depends primarily on protein synthesis. TAM-induced cytotoxicity and DNA damage appear to be explained in part by the induction of apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02307030
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  • 2
    Electronic Resource
    Electronic Resource
    Quantitative genetics of zooplankton life histories (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 454-464 
    Details
    ISSN: 1420-9071
    Keywords: Quantitative genetics ; life history ; evolution ; cladocera ; heritability ; Daphnia ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Quantitative genetic techniques are powerful tools for use in understanding the microevolutionary process. Because of their size, lifespan, and ease of culture, many zooplankton species are ideal for quantitative genetic approaches. As model systems, studies of zooplankton life histories are becoming increasingly used for examination of the central paradigms of evolutionary theory. Two of the fundamental empirical questions that zooplankton quantitative genetics studies can answer are: 1) How much genetic variance exists in natural populations for life history traits? 2) What is the empirical evidence for trade-offs that permeate life history theory based on optimality approaches? A review of existing data onDaphnia indicates substantial genetic variance for body size, clutch size, and age at first reproduction. Average broad-sense heritabilities for these three characters across 19 populations of 6 species are 0.31, 0.31, and 0.34, respectively. Although there is some discrepancy between the two pertinent studies that were designed to decompose the total genetic variance into its additive and non-additive components, a crude average seems to suggest that approximately 60% of the total genetic variance has an additive basis. The existing data are somewhat inconsistent with respect to presence/absence of trade-offs (negative genetic correlations) among life history traits. A composite of the existing data seems to argue against the existence of strong trade-offs between offspring size and offspring number, between present and future reproduction, and between developmental rate and fecundity. However, there is some evidence for a shift toward more negative (less positive) covariances in more stressful environments (e.g., low food). Zooplankton will prove to be very useful in future study in several important areas of research, including the genetics and physiology of aging, the importance of genotype-environment interaction for life history traits, and the evolution of phenotypic plasticity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02143198
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  • 3
    Electronic Resource
    Electronic Resource
    Increased induction of apoptosis in mononuclear cells of a glucose-6-phosphate dehydrogenase deficient patient (1995)
    Springer
    Journal of molecular medicine 73 (1995), S. 47-49 
    Details
    ISSN: 1432-1440
    Keywords: Glucose-6-phosphate dehydrogenase deficiency ; Apoptosis ; Glutathione ; P-Glycoprotein ; Flow cytometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Glucose-6-phosphate dehydrogenase (G6PD) deficiency belongs to the most common human disorders of metabolism. In affected patients generation of free radicals causes life-threatening hemolytic crises, for example, after consumption of certain drugs and foods or after infections. Rather than erythrocytes we analyzed mononuclear white blood cells of a patient suffering from G6PD deficiency with respect to their ability to enter apoptosis after treatment with daunorubicin, ionizing radiation, or dexamethasone. The induction of apoptosis was increased in G6PD-deficient cells compared to cells from eight normal donors. In parallel, the glutathione content of mononuclear cells from the G6PD-deficient patient was significantly decreased. While in affected patients decreased life span of erythrocytes damaged by oxidative stress has long been recognized as the mechanism underlying hemolysis, peripheral leukocytes have not received similar attention. Induction of apoptosis is a relatively complex process that has been linked to cellular glutathione content. This is the first report investigating G6PD deficiency and apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203619
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  • 4
    Electronic Resource
    Electronic Resource
    Molecular mechanisms of virus-induced carcinogenesis: the interaction of viral factors with cellular tumor suppressor proteins (1995)
    Springer
    Journal of molecular medicine 73 (1995), S. 529-538 
    Details
    ISSN: 1432-1440
    Keywords: Tumor viruses ; Hepatitis B virus ; Human papillomavirus ; Epstein-Barr virus ; Human T cell leukemia virus 1 ; Tumor suppressor proteins ; p53 ; Retinoblastoma protein ; Cell cycle ; p21 ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Accumulating evidence indicates that tumor viruses represent a major etiological factor in a significant portion of human cancers. These cancers include human papillomavirus induced anogenital cancers, hepatitis B and C virus associated hepatocellular carcinomas, nasopharyngeal carcinomas and lymphomas linked to Epstein-Barr virus infection, and human T cell leukemia virus associated adult T cell leukemias. This review summarizes the recent progress made in understanding the molecular mechanisms of viral carcinogenesis, with a particular focus on the interaction of viral factors with cellular tumor suppressor proteins. The functional inactivation of tumor suppressor proteins may represent a common strategy by which several tumor viruses contribute to malignant cell transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195138
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  • 5
    Electronic Resource
    Electronic Resource
    Fas (CD95) expression on CD4+ T cells from HIV-infected patients increases with disease progression (1995)
    Springer
    Journal of molecular medicine 73 (1995), S. 591-593 
    Details
    ISSN: 1432-1440
    Keywords: Acquired immunodeficiency syndrome ; Human immundeficiency virus ; Apoptosis ; Fas antigen (CD95) ; p24 antigen ; Immune complex dissociation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Active T cell suicide (apoptosis) is supposed to be involved in the CD4+ T cell depletion in the course of HIV infection. We investigated the expression of the apoptosis-related antigen Fas on CD4+ T cells from 25 HIV-positive individuals (CDC I-III) and 8 HIV-negative controls by two-colour flowcytometry. In addition, we evaluated: total CD4 count, HIV p24 antigen concentration in serum after immune complex dissociation, and clinical course of infection in HIV-positive individuals. We found a significant increase in mean Fas expression on CD4+ T cells from HIV-positive individuals compared to HIV-negative individuals (85.84±14.92% vs. 64.28±7.59%, P〈0.001). Within the HIV-positive group the increase in Fas expression was correlated with the decline in CD4 count (r=−0.76, P〈0.001), p24 antigen concentration in serum after immune complex dissociation (r=0.67, P〈0.001), and CDC stage (r=0.73, P〈0.001). The upregulation of Fas antigen on CD4 cells is associated with CD4 depletion and other virological and clinical marker of disease progression in HIV infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196352
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  • 6
    Electronic Resource
    Electronic Resource
    Expression of the Fas antigen on primary human leukemia cells (1995)
    Springer
    Annals of hematology 70 (1995), S. 15-17 
    Details
    ISSN: 1432-0584
    Keywords: Fas antigen ; Apoptosis ; Leukemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The antigen defined by the monoclonal antibody anti-Fas can mediate apoptosis, is associated with the receptor for tumor necrosis factor, and is expressed on a limited number of human tissues. In this study we analyzed the expression of Fas on primary human leukemic cells and on mononuclear cells from other hematologic disorders. A total of 95 samples of blood or bone marrow were studied by indirect immunofluorescence. These samples included the normal controls, 47 cases of acute myelogenous leukemia (AML), 11 cases of acute lymphoblastic leukemia (ALL), 21 cases of leukemic lymphoma, seven cases of chronic myelogenous leukemia (CML), five cases of plasma cell leukemia or multiple myeloma, and five cases of myelodysplastic or myeloproliferative syndromes. Normal controls were negative without exception. Among AML, 13/47 cases (28%) were positive; among ALL, 1/11 cases (9%) was positive; among leukemic lymphomas, 3/21 cases (14%) were positive. In a case of plasma cell leukemia which strongly expressed the Fas antigen, we demonstrated that the antibody mediates cell lysis, which was synergistically enhanced by the addition of rabbit complement. In patients with AML, Fas positivity had no obvious clinical relevance. Taken together, our results show that approximately 30% of cases of AML and occasionally other leukemias express the Fas antigens, whereas normal controls are negative in our test system. These findings may be useful in the treatment of refractory leukemias or may permit the purging of autologous transplants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01715376
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  • 7
    Electronic Resource
    Electronic Resource
    Kinetics of mitotic arrest and apoptosis in murine mammary and ovarian tumors treated with taxol (1995)
    Springer
    Cancer chemotherapy and pharmacology 35 (1995), S. 297-303 
    Details
    ISSN: 1432-0843
    Keywords: Taxol ; Mitotic arrest ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The kinetics of taxol-induced mitotic arrest and apoptosis in murine mammary carcinoma MCA-4 and ovarian carcinoma OCA-I tumors were determined to establish a possible causative relationship between mitotic arrest and apoptosis and to see whether these cellular effects of taxol would correlate with the extent of its antitumor efficacy. Mice bearing 8-mm tumors in a hind leg were given taxol i.v. at a dose of 10–80 mg/kg. Both tumors responded to taxol by significant growth delay or transient regression; in general, the response was greater as the dose of taxol was increased. For kinetics studies the mice were treated with 60 mg/kg taxol given once when tumors were 8 mm in size or twice, with the second dose being given 3 days after the first. At various times ranging from 1 to 96 h after treatment with taxol, tumors were histologically analyzed to quantify mitotic and apoptotic activity. After a single dose of taxol, mitotic arrest was visible at 1 h, and the mitotic index increased with time to reach peak values of 36% in MCA-4 tumors and 22% in OCA-I tumors at 9 h. The index then declined to a baseline of 1%–3% at 3 days for MCA-4 tumors and 1 day for OCA-I tumors. Apoptosis followed mitotic arrest, beginning at the time of peak mitotic arrest, increasing to the highest level of about 20% at 18–24 h after treatment and gradually declining to the normal level of 3%–6% after 3–4 days. Nuclear material progressively condensed in mitotically arrested cells, culminating in the frank appearance of multiple apoptotic bodies. The change in cell morphology plus the dynamics of apoptosis development imply that a large percentage of tumor cells arrested in mitosis by taxol die by apoptosis. Kinetic analysis undertaken after the second dose of taxol showed a considerably lower percentage of cells arrested in mitosis as compared with that seen after a single dose, and the induction of apoptosis by the second dose was minimal. However, the antitumor efficacy of the second dose of taxol was similar to or better than that of the first dose, implying that in addition to mitotic arrest and apoptosis, there exist other mechanisms by which taxol exerts its antitumor action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689448
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  • 8
    Electronic Resource
    Electronic Resource
    Taxol cytotoxicity on human leukemia cell lines is a function of their susceptibility to programmed cell death (1995)
    Springer
    Cancer chemotherapy and pharmacology 36 (1995), S. 385-392 
    Details
    ISSN: 1432-0843
    Keywords: Taxol ; Apoptosis ; Chemoresistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Taxol is the prototype of a class of antineoplastic drugs that target microtubules. It enhances tubulin-monomer polymerization and stabilizes tubulin polymers, increasing the fraction of cells in the G2 or M phase of the cell cycle. We report that treatment of HL-60 and U937 myeloid cell lines with 1–10 μM taxol induces DNA fragmentation and the appearance of morphological features consistent with the process of apoptosis. Taxol-induced apoptosis is inhibited neither by cycloheximide nor by actinomycin D and therefore appears to be independent of new protein synthesis. Taxol causes arrest in the G2 phase of the cell cycle and affects cell viability but does not induce DNA fragmentation in the K562 erythromyeloid cell line. Protein-synthesis inhibitors, colcemid, ionomycin, and starvation, known to trigger apoptosis, proved ineffective as well. These results suggest that the antineoplastic effect of taxol is mediated in susceptible cell lines by induction of the apoptotic machinery and that K562 partial resistance may depend upon the intrinsic inability of these tumor cells to undergo apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686187
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  • 9
    Electronic Resource
    Electronic Resource
    Taxol cytotoxicity on human leukemia cell lines is a function of their susceptibility to programmed cell death (1995)
    Springer
    Cancer chemotherapy and pharmacology 36 (1995), S. 385-392 
    Details
    ISSN: 1432-0843
    Keywords: Key words Taxol ; Apoptosis ; Chemoresistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Taxol is the prototype of a class of antineoplastic drugs that target microtubules. It enhances tubulin-monomer polymerization and stabilizes tubulin polymers, increasing the fraction of cells in the G2 or M phase of the cell cycle. We report that treatment of HL-60 and U937 myeloid cell lines with 1–10 μM taxol induces DNA fragmentation and the appearance of morphological features consistent with the process of apoptosis. Taxol-induced apoptosis is inhibited neither by cycloheximide nor by actinomycin D and therefore appears to be independent of new protein synthesis. Taxol causes arrest in the G2 phase of the cell cycle and affects cell viability but does not induce DNA fragmentation in the K562 erythromyeloid cell line. Protein-synthesis inhibitors, colcemid, ionomycin, and starvation, known to trigger apoptosis, proved ineffective as well. These results suggest that the antineoplastic effect of taxol is mediated in susceptible cell lines by induction of the apoptotic machinery and that K562 partial resistance may depend upon the intrinsic inability of these tumor cells to undergo apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686187
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  • 10
    Electronic Resource
    Electronic Resource
    Inhibitory effects of tamoxifen and tumor necrosis factor α on human glioblastoma cells (1995)
    Springer
    Cancer immunology immunotherapy 40 (1995), S. 228-234 
    Details
    ISSN: 1432-0851
    Keywords: Tumor necrosis factor α ; Tamoxifen ; Protein kinase C inhibitor ; Apoptosis ; Human glioblastoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We reported previously that tumor necrosis factor α (TNFα) inhibited proliferation and invasiveness of human malignant glial cells. Because tamoxifen, an estrogen antagonist, has also been shown to inhibit growth of such cells, we hypothesized that a combination of tamoxifen and TNFα might be more effective than either reagent alone. TNFα (1–100 ng/ml) or tamoxifen (80 ng/ml-2 μg/ml) alone inhibited proliferation of a human glioblastoma cell line (WITG3) in a dose-dependent fashion; in combination, tamoxifen and TNFα yielded additive growth inhibition. Apoptotic cells characterized by nuclear fragmentation were detectable after 48 h of TNFα or tamoxifen exposure and were significantly increased by combination treatment. In non-neoplastic human astroglia and fibroblasts, proliferation was unaffected by tamoxifen, and enhanced by TNFα as previously reported. Staurosporine (2–50 nM), which has been reported to augment the effects of TNFα, was less effective than tamoxifen against WITG3 and, in addition, was markedly inhibitory to non-neoplastic glial cells. Binding studies yielded no evidence of WITG3 estrogen or progesterone receptors, nor of tamoxifen effects on TNFα receptors. Data suggest that TNFα and tamoxifen in combination display growth-regulatory properties, which (a) are more inhibitory to human glioblastoma cells than either agent alone, (b) do not affect non-neoplastic glia, (c) do not require either estrogen/ progesterone receptors or alteration of external TNFα receptors, and (d) may involve apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01519896
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  • 11
    Electronic Resource
    Electronic Resource
    Inhibitory effects of tamoxifen and tumor necrosis factor α on human glioblastoma cells (1995)
    Springer
    Cancer immunology immunotherapy 40 (1995), S. 228-234 
    Details
    ISSN: 1432-0851
    Keywords: Key words Tumor necrosis factor α ; Tamoxifen ; Protein kinase C inhibitor ; Apoptosis ; Human glioblastoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We reported previously that tumor necrosis factor α (TNFα) inhibited proliferation and invasiveness of human malignant glial cells. Because tamoxifen, an estrogen antagonist, has also been shown to inhibit growth of such cells, we hypothesized that a combination of tamoxifen and TNFα might be more effective than either reagent alone. TNFα (1–100 ng/ml) or tamoxifen (80 ng/ml–2μ g/ml) alone inhibited proliferation of a human glioblastoma cell line (WITG3) in a dose-dependent fashion; in combination, tamoxifen and TNFα yielded additive growth inhibition. Apoptotic cells characterized by nuclear fragmentation were detectable after 48 h of TNFα or tamoxifen exposure and were significantly increased by combination treatment. In non-neoplastic human astroglia and fibroblasts, proliferation was unaffected by tamoxifen, and enhanced by TNFα as previously reported. Staurosporine (2–50 nM), which has been reported to augment the effects of TNFα, was less effective than tamoxifen against WITG3 and, in addition, was markedly inhibitory to non-neoplastic glial cells. Binding studies yielded no evidence of WITG3 estrogen or progesterone receptors, nor of tamoxifen effects on TNFα receptors. Data suggest that TNFα and tamoxifen in combination display growth-regulatory properties, which (a) are more inhibitory to human glioblastoma cells than either agent alone, (b) do not affect non-neoplastic glia, (c) do not require either estrogen/progesterone receptors or alteration of external TNFα receptors, and (d) may involve apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01519896
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  • 12
    Electronic Resource
    Electronic Resource
    Inhibition of proliferation and induction of apoptosis by abrogation of heat-shock protein (HSP) 70 expression in tumor cells (1995)
    Springer
    Cancer immunology immunotherapy 40 (1995), S. 73-78 
    Details
    ISSN: 1432-0851
    Keywords: Key words Heat-shock protein ; Tumor cells ; Apoptosis ; Proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Tumor cells often express elevated levels of heat-shock protein (HSP) 70. The present study was designed to invesitgate the role of HSP70 in the proliferation and survival of tumor cells in the human system. When Molt-4 and other tumor cells were treated in vitro with HSP70 antisense oligomer, they displayed propidium- iodide-stained condensed nuclei (intact or fragmented). A ladder-like pattern of DNA fragments was observed with HSP70 antisense-oligomer-treated tumor cells in agrose gel electrophoresis, which was consistent with internucleosomal DNA fragmentation. Flow cytometry analysis revealed the hypodiploid DNA peak of propidium-iodide-stained nuclei in the antisense-oligomer-treated cells. The apoptosis induced by HSP antisense oligomer was dose- and time-dependent. The antisense oligomer induced apoptosis mainly in tumor cells at G1 and S phase, resulting in an inhibition of cell proliferation. HSP70 antisense oligomer caused DNA-sequence-specific inhibition of HSP70 expression, which preceded apparent apoptosis. These results indicate that HSP70 antisense treatment inhibits the expression of HSP70, which in turn inhibits cell proliferation and induces apoptosis in tumor cells and suggest that HSP70 is required for tumor cells to proliferate and survive under normal condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01520287
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  • 13
    Electronic Resource
    Electronic Resource
    Correlation of p53 protein expression with apoptotic incidence in colorectal neoplasia (1995)
    Springer
    Virchows Archiv 427 (1995), S. 27-32 
    Details
    ISSN: 1432-2307
    Keywords: Apoptosis ; p53 Expression ; Colorectal cancer ; Ki-67
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The wild-type p53 gene suppresses cell proliferation and induces apoptosis when it is transfected into human colon cancer cell lines. Therefore, mutation of the p53 gene, which correlates closely with p53 protein overexpression, would be predicted to activate cell proliferation and limit apoptosis. We tested this hypothesis by correlating p53 protein expression with cell proliferation and apoptosis in 70 neoplasms (29 adenomas and 41 carcinomas) using p53 and Ki-67 immunohistochemical staining and DNA nick end labelling. The p53 immunoreactivity was independent of the Ki-67 positivity. The apoptotic incidence was less frequent (P〈0.005) in tumours with diffuse p53 protein overexpression than in those with the sporadic overexpression, defined as p53 staining of isolated or scattered expression. In addition, apoptotic incidence only correlated directly (P〈0.05) with Ki-67 positivity in tumours with sporadic p53-protein expression. These results indicate that p53 protein that is expressed sporadically in colorectal neoplasms is probably wild-type protein and induces apoptosis in response to active cell proliferation. In contrast, diffusely overexpressed p53 protein in colorectal neoplasms is probably mutant and correlates with a reduction in apoptotic cell death independently of cell proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203734
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  • 14
    Electronic Resource
    Electronic Resource
    Demonstration of apoptosis in neuroblastoma and its relationship to tumour regression (1995)
    Springer
    Virchows Archiv 427 (1995), S. 167-173 
    Details
    ISSN: 1432-2307
    Keywords: Neuroblastoma ; Apoptosis ; bcl-2 ; Fas antigen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The in vivo occurrence of apoptosis in neuroblastomas was investigated. Histologically, a number of tumour cells showed typical apoptotic changes, including cell shrinkage, condensed and fragmented nuclei, eosinophilic cytoplasm, and absence of the inflammatory response. These cells coincided closely with the so-called karyorrhectic cells. An electrophoretic DNA ladder, a functional hallmark of apoptosis, was demonstrated in four of six tumours, and DNA fragmentation was detected in situ by terminal deoxytransferase-mediated nick end-labelling in 26 of 35 tumour specimens (74%). The labelled cell counts ranged from 5 to 62 per 5000 tumour cells (mean±SD: 15.0±14.5). Immunoperoxidase staining revealed that an apoptosis-suppressing protein, bcl-2, was expressed abundantly in advanced-stage tumours, whereas it was absent from karyorrhectic-apoptotic cells. Several tumours with the potential for spontaneous regression were bcl-2-deficient. Immunostaining of the Fas receptor for apoptosis demonstrated that the tumour cells expressed this molecule on their cell surfaces. Our results provide evidence of apoptosis in neuroblastomas and suggest that bcl-2 and the Fas receptor may play a role in its regulatory mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196522
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  • 15
    Electronic Resource
    Electronic Resource
    Morphological modifications of apoptosis in HL-60 cells: effects of homocysteine and cytochalasins on apoptosis initiated by 3-deazaadenosine (1995)
    Springer
    Virchows Archiv 426 (1995), S. 257-266 
    Details
    ISSN: 1432-2307
    Keywords: Apoptosis ; 3-Deazaadenosine ; Homocysteine ; Cytochalasins ; Blebbing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using electron microscopy, confocal laser scanning microscopy and measurements of intact DNA we have studied the morphology and DNA degradation of human leukaemia HL-60 cells undergoing drug initiated apoptosis. Apoptosis was initiated by 100 μM 3-deazaadenosine (c3Ado), 25 μM c3Ado plus 1 mM homocysteine thiolactone (Hcy) and 100 μM c3Ado plus 5 μg/ml cytochalasin B (CB). Two different phenotypes of apoptotic cells (APC), blebbed and non-blebbed, were present in the cultures. Blebbed APC dominated in cultures exposed to c3Ado, whereas most APC in cultures treated with c3Ado plus Hcy and all the APC in cultures treated with c3Ado plus CB displayed a non-blebbed phenotype. A more pronounced reduction of the chromatin/cytoplasm ratio, lower volume fractions of uncondensed chromatin and higher volume fractions of highly condensed chromatin (micronuclei) were found in cultures exposed to c3Ado and c3Ado plus Hcy when compared with cultures exposed to c3Ado plus CB. A partial inhibition of c3Ado apoptosis by CB was confirmed by measurements of intact DNA. The inhibitory effect of CB was not reproducible by CE, indicating that CB exerts its effect by an actin independent mechanism. Both blebbed and non-blebbed APC displayed nuclear fragmentation, segregation of organelles and cytoplasmic vesiculation, suggesting that the differences between the phenotypes were restricted to the cytoplasmic membrane. We were not able to demonstrate the presence of F-actin by fluorescein isothiocyanate-phalloidin staining in blebbed APC nor in non-blebbed APC in cultures treated with c3Ado plus Hcy. Non-blebbed APC in cultures treated with c3Ado plus CB displayed foci of F-actin at the internal part of the cytoplasmic membrane. This suggests that F-actin is preserved by the mechanism by which CB inhibits blebbing, and may indicate that blebbing of the cytoplasmic membrane during apoptosis is associated with F-actin deficiency rather than a result of actin-myosin interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191363
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  • 16
    Electronic Resource
    Electronic Resource
    Nucleolar segregation as an early marker for DNA damage; an experimental study in rats treated with 4-hydroxyaminoquinoline 1-oxide (1995)
    Springer
    Virchows Archiv 426 (1995), S. 295-300 
    Details
    ISSN: 1432-2307
    Keywords: Nucleolar segregation ; 4-Hydroxyaminoquinoline 1-oxide ; Rat ; DNA adducts ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Male 6-week-old Sprague Dawley rats were given a single intravenous injection of 4-hydroxyamino-quinoline 1-oxide (4HAQO) at a dose of 20 mg/kg in order to produce ultrastructural changes as possible morphological biomarkers for toxicity. Immunohistochemically demonstrated formation of 4HAQO-DNA adduct was correlated with the changes found. Nucleolar alteration, demonstrable by electron microscopy as segregation of nucleolar components into granular and fibrillar compartments, was evident in cells of the target organs, exocrine pancreas and adrenocortex, but not of the non-target liver parenchyma. Sequential observation clarified that such alteration was highest in frequency 6 h and 4 h after 4HAQO administration in pancreatic acinar cells and adrenocortical cells respectively. Electron microscopically, apoptotic changes of acinar cells were evident 2 h after injection of 4HAQO. DNA adduct formation was consistently demonstrated in the same target organs showing nucleolar segregation, the highest frequency being noted 4 h after 4HAQO treatment in both pancreatic acinar cells and adrenocortical cells. Our results thus indicate an identity of the target cells for nucleolar segregation and 4HAQO-DNA adduct formation which correlates with 4HAQO-toxicity. We suggest that nucleolar segregation occurs subsequent to the generation of DNA damage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191367
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  • 17
    Electronic Resource
    Electronic Resource
    bcl-2 protein in invasive ductal breast carcinomas (1995)
    Springer
    Virchows Archiv 426 (1995), S. 163-168 
    Details
    ISSN: 1432-2307
    Keywords: bcl-2 ; Apoptosis ; Breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The bcl-2 gene encodes a protein which inhibits programmed cell death (apoptosis). This protein was detected by immunohistochemical techniques in 48% of invasive ductal carcinomas of the breast. It was present in well-differentiated carcinomas with hormonal receptors, and proteins synthesized under the control of oestrogens: pS2, cathepsin D and ERD5. In contrast, bcl-2+ carcinomas are less frequently positive for p53 and have a Ki67 score under the mean. bcl-2 protects cells against apoptosis. Accumulation of p53 protein, which is indicative of p53 mutation, would have the same effect; however, these two proteins seem inversely related, an inverse correlation observed by others in breast cancer cell lines and in lymphomas. Tumours positive for bcl-2 escape apoptosis and have worse prognosis but this is not what is found; survival at 5 years, and particularly the absence of recurrence during the first 5 years after surgery, seem to be associated with bcl-2 positivity. The bcl-2 protein seems only to be an important prognostic factor in women over 54 years of age. Moreover, p53− bcl-2+ tumours have a better response to hormonal therapy than p53− bcl-2− tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192638
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  • 18
    Electronic Resource
    Electronic Resource
    Apoptosis and cellular proliferation in oesophageal squamous cell carcinomas: differences between keratinizing and nonkeratinizing types (1995)
    Springer
    Virchows Archiv 427 (1995), S. 271-276 
    Details
    ISSN: 1432-2307
    Keywords: Oesophageal squamous cell carcinoma ; Apoptosis ; Cell growth ; p53 Protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To assess cell death and cellular proliferation activity, the apoptosis index, the Ki67 proliferative index and overexpression of p53 protein were evaluated in 69 oesophageal squamous cell carcinomas (ESCC), all surgically resected from Japanese patients. Apoptosis was examined by Gavrieli's method in histological sections, and proved to be significantly related to keratinization and ESCC progression. Overall labelling indices were 15.68±4.04 (positive/1,000 nuclei) and 6.79±0.64 respectively, in keratinizing and nonkeratinizing types. The apoptosis labelling index increased, especially in keratinizing lesions, from 4.50±0.59 with cancer invasion to mucosa through 11.46±2.70 with involvement of the submucosa up to 21.18±3.72 in cases of penetration to the muscularis propria or adventitia. The relationship between apoptosis, Ki67 scores and p53 expression was determined in identical cancer nests on serial sections. An inverse correlation was shown between the apoptosis score and the Ki67 score in both keratinizing and nonkeratinizing types. There was no significant correlation between apoptosis score and p53 expression, either overall or separately in keratinizing or nonkeratinizing types of ESCC. Our results suggest that a mechanism of induction of apoptosis similar to that operating in normal epidermis acts in keratinizing ESCC, and that as tumour volume increases, single cell death becomes more frequent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203394
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  • 19
    Electronic Resource
    Electronic Resource
    Both apoptosis and necrosis occur following intrastriatal administration of excitotoxins (1995)
    Springer
    Acta neuropathologica 90 (1995), S. 504-510 
    Details
    ISSN: 1432-0533
    Keywords: Apoptosis ; Necrosis ; Kainic acid ; Quisqualic acid ; Quinolinic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To learn about the mechanisms of excitotoxic cell death in vivo, three different excitatory amino acid receptor agonists (kainic acid, quinolinic acid or quisqualic acid) were injected in the left striatum of adult rats. Brains were examined at 24 and 48 h after injection. Morphological and biochemical studies were performed using conventional stains, histochemistry, in situ labelling of nuclear DNA fragmentation, and agarose gel electrophoresis of extracted DNA. Large numbers of cells with cytoplasmic shrinkage and nuclear condensation or granular degeneration of the chromatin, and fewer cells with apoptotic morphology were distributed at random in the injured areas of the three groups of treated animals but not in rats injected with vehicle alone. A ladder pattern, typical of internucleosomal DNA fragmentation, was observed 24 h after treatment. This was replaced by a smear pattern, consistent with random DNA breakdown, at 48 h. These morphological and biochemical results suggest that prevailing necrosis together with apoptosis occur following intrastriatal injection of different excitotoxins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294812
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  • 20
    Electronic Resource
    Electronic Resource
    A rat model of HTLV-I infection: development of chronic progressive myeloneuropathy in seropositive WKAH rats and related apoptosis (1995)
    Springer
    Acta neuropathologica 89 (1995), S. 483-490 
    Details
    ISSN: 1432-0533
    Keywords: Key words HTLV-I ; HTLV-I-associated ; myelopathy/tropical spastic paraparesis ; Rat model ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In seropositive HTLV-I carrier rats of the WKAH strain inoculated with 2 × 107 MT-2 cells at 3–6 months of age, chronic progressive myeloneuropathy, tentatively designated as HTLV-I-associated myelopathy (HAM) rat disease, occurred when the rats were 19–23 months old. Clinical and pathological findings were basically identical to those of seronegative HAM rats of the same strain neonatally inoculated with MT-2 cells. It appears that a high dose of MT-2 cells (108 cells) is more effective for the induction and acceleration of HAM rat disease. Seronegative and seropositive carriers of other strains (F344, ACI, and LEW), WKAH rats inoculated with HUT-78 (a human T cell line without HTLV-I infection), and untreated WKAH rats at comparable ages did not develop HAM rat disease, thereby indicating that development of this disease is caused by HTLV-I infection and is under strict genetic restriction of the host strain. Chronological examination of HAM rat disease induced by 107 MT-2 inoculation into newborn rats showed that the spinal cord lesion began to develop by 12 months of age. T cells were absent in the affected spinal cord throughout the disease process. There was morphological evidence of apoptotic death of oligodendrocytes in the affected spinal cord. Apoptosis was also confirmed by the specific nick end labeling of the nuclear fragmentation in situ, and the apoptotic oligodendrocytes confined to the demyelinating foci, and the number of apoptotic cells positively correlated with severity of the spinal cord lesion. The collective evidence suggests that the major pathogenetic pathway of HAM rat disease appears to be closely related to apoptotic death of the oligodendrocytes, directly or indirectly associated with HTLV-I infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571502
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  • 21
    Electronic Resource
    Electronic Resource
    Apoptotic process of cerebellar degeneration in experimental methylmercury intoxication of rats (1995)
    Springer
    Acta neuropathologica 91 (1995), S. 72-77 
    Details
    ISSN: 1432-0533
    Keywords: Key words Cerebellar degeneration ; Methylmercury ; intoxication ; Apoptosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report deals with the mechanism involved in the cerebellar degeneration following experimental methylmercury poisoning of male Wistar rats. The cerebellar granule cells of animals that exhibited typical hind leg paresis were shrunken and displayed marked nuclear pyknosis. At the ultrastructural level, the nuclei of these cells were condensed and fragmented, features which are characteristic of apoptosis. In situ staining for DNA strand breaks revealed that the pyknotic nuclei were positively labeled. DNA fragmentation was confirmed by agarose gel electrophoresis; a ladder pattern of multiples of approximately 200-base pair fragments, typical of apoptosis, was observed with the cerebellar DNA of the methylmercury-treated animals. These observations suggest that the degeneration of cerebellar granule cells by alkyl mercury compounds involves an apoptotic process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050394
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  • 22
    Electronic Resource
    Electronic Resource
    A rat model of HTLV-I infection: development of chronic progressive myeloneuropathy in seropositive WKAH rats and related apoptosis (1995)
    Springer
    Acta neuropathologica 89 (1995), S. 483-490 
    Details
    ISSN: 1432-0533
    Keywords: HTLV-I ; HTLV-I-associated ; myelopathy/tropical spastic paraparesis ; Rat model ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In seropositive HTLV-I carrier rats of the WKAH strain inoculated with 2×107 MT-2 cells at 3–6 months of age, chronic progressive myeloneuropathy, tentatively designated as HTLV-I-associated myelopathy (HAM) rat disease, occurred when the rats were 19–23 months old. Clinical and pathological findings were basically identical to those of seronegative HAM rats of the same strain neonatally inoculated with MT-2 cells. It appears that a high dose of MT-2 cells (108 cells) is more effective for the induction and acceleration of HAM rat disease. Seronegative and seropositive carriers of other strains (F344, ACI, and LEW), WKAH rats inoculated with HUT-78 (a human T cell line without HTLV-I infection), and untreated WKAH rats at comparable ages did not develop HAM rat disease, thereby indicating that development of this disease is caused by HTLV-I infection and is under strict genetic restriction of the host strain. Chronological examination of HAM rat disease induced by 107 MT-2 inoculation into newborn rats showed that the spinal cord lesion began to develop by 12 months of age. T cells were absent in the affected spinal cord throughout the disease process. There was morphological evidence of apoptotic death of oligodendrocytes in the affected spinal cord. Apoptosis was also confirmed by the specific nick end labeling of the nuclear fragmentation in situ, and the apoptotic oligodendrocytes confined to the demyelinating foci, and the number of apoptotic cells positively correlated with severity of the spinal cord lesion. The collective evidence suggests that the major pathogenetic pathway of HAM rat disease appears to be closely related to apoptotic death of the oligodendrocytes, directly or indirectly associated with HTLV-I infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571502
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  • 23
    Electronic Resource
    Electronic Resource
    Cell death in the olfactory epithelium (1995)
    Springer
    Anatomy and embryology 192 (1995), S. 77-87 
    Details
    ISSN: 1432-0568
    Keywords: Cell death ; Olfactory epithelium ; RNA synthesis ; Fragmented DNA ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the nervous system of vertebrates the olfactory epithelium presents unique cytological characteristics. In the olfactory mucosa, olfactory neurons die and are replaced from undifferentiated neuroblasts over the entire life span of the animal. It remains unclear whether these neurons die as a result of a direct insult from the environment or in fulfillment of a physiological program of cell death. We have studied the distribution and the characteristics of cell death in the olfactory epithelium of normal, adult rats. The olfactory epithelium contains pycnotic bodies resembling those described for thymocytes undergoing terminal apoptotic changes. These appear at all levels in the epithelium, under both light and electron microscopes and can also be demonstrated after vital staining with acridine orange. Chromatin condensation into large blocks, often located at the nuclear periphery, is a morphological hallmark of the nuclei of mature olfactory neurons, which also present an increase in electron density of the cytoplasm. After non-radioactive in situ labeling of fragmented DNA, the nuclei of olfactory neurons are positive. Under the same reaction conditions (mild protease digestion), most of the nuclei of the supporting and basal cells are negative. In vivo incorporation of 5-bromouridine, a marker of RNA synthesis, is also lower in olfactory neurons than in basal and supporting cells. These findings suggest that olfactory neurons are committed very early to physiological cell death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186993
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  • 24
    Electronic Resource
    Electronic Resource
    Pharyngosellar pituitary: a rare developmental anomaly of the pituitary gland (1995)
    Springer
    Acta neuropathologica 89 (1995), S. 459-463 
    Details
    ISSN: 1432-0533
    Keywords: Apoptosis ; Bcl-2 ; Pituitary malformation ; Pharyngeal pituitary ; Pharyngosellar pituitary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A rare malformation of the pituitary gland, termed pharyngosellar pituitary, is reported. The anterior pituitary gland was continuous from the pharyngeal roof to the sella turcica. This was found in a male fetus of gestational week 17 with an encephalocele and aminion adhesion malformation syndrome. The distribution of hormone-producing cells in the malformed pituitary tissue was irregular: thyrotropic hormone-, follicle-stimulating hormone- and luteinizing hormone-producing cells were nearly absent in the sellar and middle sections of the pituitary but were found in small numbers mainly in the pharyngeal section of the pituitary. The teratogenic determination period was estimated at between weeks 4 and 8 of gestation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307653
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  • 25
    Electronic Resource
    Electronic Resource
    Expression of the Fas antigen on primary human leukemia cells (1995)
    Springer
    Annals of hematology 70 (1995), S. 15-17 
    Details
    ISSN: 1432-0584
    Keywords: Key words Fas antigen ; Apoptosis ; Leukemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary  The antigen defined by the monoclonal antibody anti-Fas can mediate apoptosis, is associated with the receptor for tumor necrosis factor, and is expressed on a limited number of human tissues. In this study we analyzed the expression of Fas on primary human leukemic cells and on mononuclear cells from other hematologic disorders. A total of 95 samples of blood or bone marrow were studied by indirect immunofluorescence. These samples included the normal controls, 47 cases of acute myelogenous leukemia (AML), 11 cases of acute lymphoblastic leukemia (ALL), 21 cases of leukemic lymphoma, seven cases of chronic myelogenous leukemia (CML), five cases of plasma cell leukemia or multiple myeloma, and five cases of myelodysplastic or myeloproliferative syndromes. Normal controls were negative without exception. Among AML, 13/47 cases (28%) were positive; among ALL, 1/11 cases (9%) was positive; among leukemic lymphomas, 3/21 cases (14%) were positive. In a case of plasma cell leukemia which strongly expressed the Fas antigen, we demonstrated that the antibody mediates cell lysis, which was synergistically enhanced by the addition of rabbit complement. In patients with AML, Fas positivity had no obvious clinical relevance. Taken together, our results show that approximately 30% of cases of AML and occasionally other leukemias express the Fas antigens, whereas normal controls are negative in our test system. These findings may be useful in the treatment of refractory leukemias or may permit the purging of autologous transplants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01715376
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  • 26
    Electronic Resource
    Electronic Resource
    Effects of adult T-cell leukaemia-derived factor on ultraviolet radiation-induced skin injury (1995)
    Springer
    Archives of dermatological research 287 (1995), S. 498-499 
    Details
    ISSN: 1432-069X
    Keywords: Adult T-cell leukaemia-derived factor ; Apoptosis ; Skin injury ; Sunburn cell ; Ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00373435
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  • 27
    Electronic Resource
    Electronic Resource
    Keratinocytes constitutively express the Fas antigen that mediates apoptosis in IFNγ-treated cultured keratinocytes (1995)
    Springer
    Archives of dermatological research 287 (1995), S. 315-320 
    Details
    ISSN: 1432-069X
    Keywords: Keratinocytes ; Fas antigen ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The Fas antigen is a cell surface protein that can mediate apoptosis in many cell types. Although its physiological function is still unclear, recent evidence indicates that this surface molecule is involved in apoptosis in the immune system and the liver. The epidermis is an organ that undergoes terminal differentiation with the eventual death of keratinocytes, and it has been suggested that this is a specialized form of apoptosis. In the present study, we examined whether or not the Fas antigen is involved in keratinocyte apoptosis. Immunoreactivity for the Fas antigen was found throughout the epidermis in normal human skin sections and cultured normal human keratinocytes, and mRNA for the Fas antigen was found to be constitutively expressed in normal epidermis and cultured normal keratinocytes by RT-PCR analysis. To determine whether the Fas antigen in keratinocytes is functional, we used a cytotoxic monoclonal antibody (mAb) against the Fas antigen to induce apoptosis. This antibody did not induce apoptosis of cultured keratinocytes even though they expressed the Fas antigen. We then tested the ability of several cytokines (TGFβ, TNFα and IFNγ) to induce Fas-mediated keratinocyte apoptosis. Only pretreatment with IFNγ followed by the addition of the anti-Fas mAb induced apoptosis, as assessed by cell viability, morphological changes and ultrastructural characteristics, suggesting that constitutive expression of the Fas antigen is not sufficient to induce apoptosis in keratinocytes and that keratinocyte apoptosis via the Fas antigen-mediated mechanism may require the activation of keratinocytes by IFNγ, which is thought to be produced by activated T cells. The Fas antigen may not be related to keratinocyte apoptosis that occurs in terminal differentiation, but rather to the apoptosis that occurs in inflammatory skin diseases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01105085
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  • 28
    Electronic Resource
    Electronic Resource
    Establishment and characterization of a novel CD34-positive human myeloid leukemia cell line: MHH225 growing in serum-free culture (1995)
    Springer
    Annals of hematology 71 (1995), S. 111-117 
    Details
    ISSN: 1432-0584
    Keywords: Apoptosis ; CD34 ; Interferon-alpha ; Leukemia ; Stem cell factor ; TNF-alpha
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A new human multilineage myeloid leukemia cell line, MHH225, has been established in our laboratory from the bone marrow of a 60-year-old patient suffering from acute megakaryoblastic leukemia (M7); it provides a unique model for studying the effect of biologic and chemical agents on the lineage specificity of a multipotent myeloid leukemia clone containing a mixed population of megakaryoblast, erythroblast, and myeloblast cells in a serum-free culture. Morphologically, all 225 cells are large blast cells with basophilic cytoplasm containing no granules, large round nucleus containing 2–3 prominent nucleoli, and fine chromatin structure and a large nuclear/cytoplasm ratio. The MHH225 cells are CD34+HLA-DR+CD33+CD13+ with 57.6%, 28.3%, and 7.8% of them being CD41+, glycophorin A+, and CD15+, respectively, and all lymphoid-specific antigens are negative. The karyotype analysis of MHH225 cells revealed a deletion of the short arm of chromosome 7: del(7)(p13)-, a whole-arm translocation between the long arms of chromosomes 9 and 21: t(9;21)(q10;q10), and a chromosome 11 with an elongated long arm due to duplication of chromosome 11 material as well as to translocation of part of chromosome 9 onto 11q+. Also, chromosome 21 was deleted in some metaphases or showed a ring formation in other metaphases. Utrastructurally, MHH25 cells display a strong platelet peroxidase activity in the nuclear envelope and the endoplasmic reticulum. The MHH25 cells have been grown exponentially without growth factors or conditioned media or serum only in RPMI1640 culture medium. None of the myelopoietic growth factors, i.e., interleukin-3, GM-CSF, G-CSF, erythropoietin, or interleukin-6, has any effect on the proliferation and differentiation of MHH25 cells. The two, hematopoietic inhibitory cytokines, interferon-alpha and tumor necrosis factor-alpha, have only minimal growth inhibitory effect. Stem cell factor showed only weak growth-stimulatory effect on MHH225 cells but significantly inhibited chemotherapy-induced apoptosis in these cells. The new cell line MHH225 should constitute a useful model for studying stem cell antigen (CD34)-positive human multilineage myeloid leukemia cells carrying a deletion in the short arm of chromosome 7 and an aberration in chromosome 11 and provide a unique tool for investigating human hematopoietic stem cell biology and its cytokine regulation in serum-free cultures. To our knowledge, the MHH225 cell line is the first human CD34-positive leukemia cell line growing in serum-free cultures to be established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01702645
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  • 29
    Electronic Resource
    Electronic Resource
    Programmed cell death at the periphery of the pupal wing of the butterfly, Pieris rapae (1995)
    Springer
    Development genes and evolution 204 (1995), S. 418 
    Details
    ISSN: 1432-041X
    Keywords: Lepidopteran insect ; Butterfly wing ; Programmed cell death ; Apoptosis ; Wing morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The outline of the adult wing of lepidopteran insects (butterflies and moths) emerges as a result of disappearance of a group of cells at the periphery of the pupal wing. Histological observation of the pupal wing of Pieris rapae showed that, just after apolysis of the wing epithelium from the pupal cuticle, there occurs a rapid and localized decrease of the number of cells at the periphery of the wing. This decrease occurs through cell death, which lasts 1–1.5 days at 20°C. Dying cells lose contact with the neighbouring cells and show condensation of chromatin and cytoplasm. They then appear to be phagocytosed by neighbouring epithelial cells or discharged through the basal surface of the epithelium into the lumen within the wing and taken up by phagocytes. Fragmentation of DNA in the nuclei was detected in the dead cells or their debris. These results indicate that programmed cell death in the lepidopteran wing proceeds through a mechanism closely similar to that of apoptosis in the vertebrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00360849
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  • 30
    Electronic Resource
    Electronic Resource
    On the elevated intestinal pH of higher termites (Isoptera: Termitidae) (1995)
    Springer
    Insectes sociaux 42 (1995), S. 57-69 
    Details
    ISSN: 1420-9098
    Keywords: Hindgut ; alkalinity ; evolution ; symbionts ; gut morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pH of the gut contents was measured in 52 species of higher termites (Termitidae), representing 36 genera in all four subfamilies. A statistically significant trend was shown from lower termites with low mean gut pH through to the Termitinae with higher mean gut pHs. Elevation of the pH occurred principally in the first and third proctodaeal segments, reaching values as high as 10.5 in 8 soil-feeding genera and 1 wood-feeding genus of Termitinae. Elevation of gut pH within the Termitidae appears to be independent of the general nature of the feeding substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01245699
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  • 31
    Electronic Resource
    Electronic Resource
    Fludarabine- and gemcitabine-induced apoptosis: incorporation of analogs into DNA is a critical event (1995)
    Springer
    Cancer chemotherapy and pharmacology 36 (1995), S. 181-188 
    Details
    ISSN: 1432-0843
    Keywords: Apoptosis ; Nucleoside analog ; DNA incorporation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The nucleoside analogs fludarabine and gemcitabine inhibit cellular DNA synthesis by two different mechanisms: (1) direct termination of DNA strand elongation after the triphosphate of each drug is incorporated into DNA; and (2) indirect inhibition of DNA synthesis by decreasing cellular dNTPs through inhibition of ribonucleotide reductase. The present study demonstrated that incorporation of the analogs into DNA is critical for the cytotoxic action of these drugs in human T lymphoblastoid CEM cells. S phase cells, which actively incorporated the analogs into DNA, were most sensitive to the cytotoxic action of these compounds. A relatively short-term (5–24 h) cessation of cellular DNA synthesis without analog incorporation was not sufficient to cause cell death. The drug-treated cells died through apoptosis characterized by generation of internucleosomal DNA fragmentation and apoptotic morphology. Induction of high molecular mass (50–500 kb) DNA fragmentation was also observed in cells undergoing apoptosis; this type of DNA degradation was strongly correlated with the analog-induced cell death process. Inhibition of the analog incorporation into DNA by aphidicolin blocked both types of DNA fragmentation and apoptotic morphology, indicating the essential role of analog incorporation into DNA in drug-induced cell death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685844
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  • 32
    Electronic Resource
    Electronic Resource
    Kinetics of mitotic arrest and apoptosis in murine mammary and ovarian tumors treated with taxol (1995)
    Springer
    Cancer chemotherapy and pharmacology 35 (1995), S. 297-303 
    Details
    ISSN: 1432-0843
    Keywords: Key words Taxol ; Mitotic arrest ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The kinetics of taxol-induced mitotic arrest and apoptosis in murine mammary carcinoma MCA-4 and ovarian carcinoma OCA-I tumors were determined to establish a possible causative relationship between mitotic arrest and apoptosis and to see whether these cellular effects of taxol would correlate with the extent of its antitumor efficacy. Mice bearing 8-mm tumors in a hind leg were given taxol i.v. at a dose of 10–80 mg/kg. Both tumors responded to taxol by significant growth delay or transient regression; in general, the response was greater as the dose of taxol was increased. For kinetics studies the mice were treated with 60 mg/kg taxol given once when tumors were 8 mm in size or twice, with the second dose being given 3 days after the first. At various times ranging from 1 to 96 h after treatment with taxol, tumors were histologically analyzed to quantify mitotic and apoptotic activity. After a single dose of taxol, mitotic arrest was visible at 1 h, and the mitotic index increased with time to reach peak values of 36% in MCA-4 tumors and 22% in OCA-I tumors at 9 h. The index then declined to a baseline of 1%–3% at 3 days for MCA-4 tumors and 1 day for OCA-I tumors. Apoptosis followed mitotic arrest, beginning at the time of peak mitotic arrest, increasing to the highest level of about 20% at 18–24 h after treatment and gradually declining to the normal level of 3%–6% after 3–4 days. Nuclear material progressively condensed in mitotically arrested cells, culminating in the frank appearance of multiple apoptotic bodies. The change in cell morphology plus the dynamics of apoptosis development imply that a large percentage of tumor cells arrested in mitosis by taxol die by apoptosis. Kinetic analysis undertaken after the second dose of taxol showed a considerably lower percentage of cells arrested in mitosis as compared with that seen after a single dose, and the induction of apoptosis by the second dose was minimal. However, the antitumor efficacy of the second dose of taxol was similar to or better than that of the first dose, implying that in addition to mitotic arrest and apoptosis, there exist other mechanisms by which taxol exerts its antitumor action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689448
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  • 33
    Electronic Resource
    Electronic Resource
    Induction of apoptosis in cultured retinoblastoma cells by the protein phosphatase inhibitor, okadaic acid (1995)
    Springer
    Journal of cancer research and clinical oncology 121 (1995), S. 729-738 
    Details
    ISSN: 1432-1335
    Keywords: Apoptosis ; DNA fragmentation ; Okadaic acid ; Retinoblastoma cell line ; Retinal pigment epithelial cell line ; Mitotic arrest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The induction of apoptosis in cultured retinoblastoma cells by diverse drugs was examined by analyzing DNA fragmentation, a hallmark of apoptosis. First, the ability of six retinoblastoma cell lines to undergo apoptosis was surveyed using etoposide (30 μg/ml, 20 h exposure). The NCC-RbC-60 cell line, established in this laboratory, showed DNA fragmentation clearly, whereas the other cell lines tested, including the representative retinoblastoma cell line, Y-79, did not show distinct DNA fragmentation. Biochemical modulators, such as A23187, forskolin, retinoic acid, phorbol 12-myristate 13-acetate and okadaic acid, were examined to ascertain whether they could induced apoptosis in NCC-RbC-60 and Y-79 cells after exposure for 20 h. Only okadaic acid induced DNA fragmentation in all the retinoblastoma cell lines tested and it induced DNA fragmentation in Y-79 cells in a time- and concentration-dependent manner. Flow-cytometric analysis and microscopic examination revealed that Y-79 cells treated with okadaic acid for 24–48 h accumulated at the G2/M, especially M, phases, before undergoing DNA fragmentation. Other mitotic poisons, nocodazole, colcemid and taxol, also induced apoptosis in Y-79 cells. In the K1034 cell line, established from non-malignant retinal pigmental epithelium, okadaic acid failed to induce both G2/M arrest and DNA fragmentation. These findings suggest that okadaic-acid-induced apoptosis occurs as a result of metaphase arrest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01213319
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  • 34
    Electronic Resource
    Electronic Resource
    Apoptose und Zellproliferation bei HHV-6-Infektionen Regulationsmechanismen über p 53/bcl-2/ras-Interaktionen (1995)
    Springer
    Der Pathologe 16 (1995), S. 120-127 
    Details
    ISSN: 1432-1963
    Keywords: Schlüsselwörter HHV-6-Hodgkin-Lymphom ; Kikuchi-Lymphadenitis ; Onkogene ; Antionkogene ; Apoptose ; Key words HHV-6-Hodgkin's disease ; Kikuchi lymphadenitis ; Oncogens ; Antioncogenes ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary HHV-6 infected immature T (HSB 2) and Hodgkin (HDLM 2) cells and biopsy tissues from lymph nodes of patients with Hodgkin's disease (HD) and Kikuchi lymphadenitis (KL) were studied immunohistologically for virus antigen expression and for the oncogene/anti-oncogene products ras, bcl-2 and p 53. Cell proliferation and cell death were tentatively monitored in tissue culture by PCNA staining, by viability testing and in situ end labeling of fragmented DNA. PCNA was also used in biopsy samples. KL is characterized by high incidences of focal cell death (i. e. histiocytic necrotizing lymphadenitis), while HD is apparently more a proliferative disease. The techniques used revealed no significant differences in the cellular expression of viral DNA or antigens among cell lines, HD or KL. The HDLM 2 cell line with the superior survival after HHV-6 infection showed a significantly lower expression of p 53 and PCNA than HSB 2 cells. Biopsy samples from patients with KL did not express p 53, and ras and PCNA were observed in fewer cells than in HD. Bcl-2, however, was significantly more frequently seen than in HD. The interpretation of the data is difficult; they suggest that there are additional regulatory influences in control of cell proliferation and cell death, such as cytokines and growth factors, which are altered after viral infection. Also, virus-induced cell death probably includes other mechanisms besides apoptosis, such as cell damage caused by oxygen radicals.
    Notes: Zusammenfassung HHV-6-infizierte Zellkulturlinien (HSB 2 T-Zellen; HDLM 2-Hodgkin-Zellen) sowie Biopsieproben von HHV-6-positiven Hodgkin(HD)- und Kikuchi-Lymphomen (KL) wurden immunhistologisch auf eine Expression der Genprodukte ras, bcl-2 und p 53 untersucht und die Ergebnisse korreliert mit Markern der Zellproliferation und mit Zeichen apoptotischen Zelltods. Die Ergebnisse der Zellkulturuntersuchungen sind eingeschränkt beurteilbar, da etablierte Zellinien bereits transformiert sind. Dennoch zeigen die Zellen mit geringerer Apoptoserate (HDLM 2) eine 10 fach geringere p 53-Expression und eine um die Hälfte verminderte PCNA-Anfärbung der Zellen. In den Biopsien des stärker nekrotisierenden KL war lediglich 1/6 bis 1/20 der ras-Expression des HD nachweisbar, p 53 fehlte gänzlich, während bcl-2 deutlich gegenüber dem HD gesteigert war. PCNA-positive Zellen waren beim HD etwa 3 mal so häufig, wie beim KL. Es fanden sich keine signifikanten Unterschiede in der Virus-DNS oder Antigenexpression bei den verschiedenen untersuchten Zellen. Die Ergebnisse lassen vermuten, daß weitere exogene Faktoren wie Zytokine und Wachstumsfaktoren in den Regelmechanismus für virusinduzierte Zellproliferation und Apoptose eingreifen, und daß neben der Apoptose andere Formen der viralen Zellyse vorkommen.
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    URL: http://dx.doi.org/10.1007/s002920050084
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  • 35
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    Electronic Resource
    Expression of clusterin (testosterone-repressed prostate message-2) mRNA during growth and regeneration of rat liver (1995)
    Springer
    Archives of toxicology 69 (1995), S. 253-258 
    Details
    ISSN: 1432-0738
    Keywords: Key words Clusterin ; Liver ; Apoptosis ; Mitosis ; Necrosis ; Cyproterone acetate ; Carbon tetrachloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Clusterin has been used as a marker for apoptosis (often denoted “active”“or programmed” cell death) in the prostate, mammary gland and other solid organs. The protein is thought to be involved in membrane remodelling during separation of apoptotic cells from their vital neighbours and fragmentation into apoptotic bodies. In the present study, we have looked at the expression of clusterin during the growth and regression of rat liver induced by short term administration of the hepatomitogen, cyproterone acetate. The steady state level of clusterin mRNA, as measured by Northern and slot blot analysis, is low in control hepatocytes. Following administration of cyproterone acetate, the clusterin mRNA level is increased during both liver growth and regression. In situ hybridization reveals that clusterin is expressed in all hepatocytes, indicating that it is not confined to cell death by apoptosis. These results suggest that the gene product may be involved in maintaining membrane integrity, which is necessary during both mitosis and apoptosis. To determine whether clusterin mRNA is induced by membrane remodelling independent of either mitosis or apoptosis, we examined the expression of clusterin mRNA in the liver after a necrogenic dose of carbon tetrachloride. During the first 24–48 h of this time period, necrosis is the predominant form of cell death and liver regeneration starts after approximately 24 h. Elevated levels of clusterin mRNA are found as early as 12 h after carbon tetrachloride administration and persist for at least 72 h. Clusterin expression in tissues such as the prostate and mammary gland appears to be confined to the apoptotic pathway; however, our results suggest that in hepatocytes, the expression of the gene is induced in processes other than apoptosis, including mitosis and necrosis. These processes involve substantial membrane remodelling, suggesting that clusterin expression may be induced by perturbations in the normal membrane structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050167
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  • 36
    Electronic Resource
    Electronic Resource
    Bcl-2 expression and its association with cell kinetics in human gastric carcinomas and intestinal metaplasia (1995)
    Springer
    Journal of cancer research and clinical oncology 121 (1995), S. 357-363 
    Details
    ISSN: 1432-1335
    Keywords: bcl-2 ; Ki-67 ; Apoptosis ; p53 ; Gastric carcinoma ; Intestinal metaplasia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Thebcl-2 protooncogene was initially discovered at the t(14;18) chromosomal breakpoint in follicular lymphomas. It has been demonstrated thatbcl-2 protein (Bcl-2) expression blocks apoptosis and plays an important role in cell development and maturation. In the present study, Bcl-2 expression was immunohistochemically examined in 103 cases of gastric carcinoma, as well as 64 cases of non-carcinous gastric mucosa, and its correlation with apoptosis, cell proliferation and p53 immunoreactivity was investigated. Bcl-2 was detected in 18.0% of differentiatedtype gastric carcinomas (9 of 50) and 7.5% of the undifferentiated type (4 of 53). In adjacent intestinal metaplastic gastric epithelium, the incidence of Bcl-2 positivity in the incomplete type (21/23, 91.3%) was significantly higher than in the complete type (23/41, 56.1%) (P〈0.04). Double immunostaining for Bcl-2 and Ki-67 clearly revealed the majority of Bcl-2-positive cancer cells to be in a nonproliferating state, although some cancer cells expressed both proteins together. Statistical assessment demonstrated that the average Ki-67 labeling index and apoptotic labeling index in Bcl-2-positive foci were significantly lower than in Bcl-2-negative foci (P〈0.0001,P〈0.0003). In addition, a significant dissociation between Bcl-2 and p53 immunoreactivity was found in cancer tissues. These results indicate that aberrant Bcl-2 expression in gastric carcinomas possibly originates from intestinal metaplastic epithelium, and suggest a possible role in tumor development and growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01225688
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  • 37
    Electronic Resource
    Electronic Resource
    Biophysical, pharmacological and developmental properties of ATP-sensitive K+ channels in cultured myotomal muscle cells from Xenopus embryos (1995)
    Springer
    Pflügers Archiv 429 (1995), S. 607-616 
    Details
    ISSN: 1432-2013
    Keywords: Myoblasts ; K+ channel openers ; Sulphonylureas ; Rigor ; Metabolic exhaustion ; Muscle fatigue ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Unlike mammalian muscle cells in culture, cultured myotomal muscle cells of Xenopus embryos express ATP-sensitive K+ (KATP) channels. The KATP channels are blocked by internal ATP (half-maximal inhibition K 0.5 = 16 μM) and to a lesser extent by internal ADP, are voltage independent, have an inward rectification at positive potentials and are inhibited by glibenclamide (K 0.5 = 2 μM). Surprisingly, these KATP channels are not sensitive to K+ channel openers such as cromakalim. Opening of these KATP channels does not occur under normal physiological conditions. It is elicited by metabolic exhaustion of the muscle cell and it precedes the development of an irreversible rigor state. Neither intracellular acidosis nor an increase of intracellular Ca2+ are involved in KATP channel opening. Different types of K+ channels are successively expressed after plating of myotomal muscle cells: (1) sustained delayed-rectifier K+ channels; (2) KATP channels; (3) inward-rectifier K+ channels; (4) transient delayed-rectifier K+ channels. The current density associated with KATP channels far exceeds that of voltage-dependent K+ channels. Innervation controls the expression of these KATP channels. Co-culture of muscle cells with neurons from the neural tube decreases the number of active KATP channels per patch. Similarly, in situ innervated submaxillaris muscle of tadpoles at stage 50–55 has a very low density of KATP channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00373981
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  • 38
    Electronic Resource
    Electronic Resource
    Fluctuation of body temperature and cuckoo brood parasitism (1995)
    Springer
    Ecological research 10 (1995), S. 321-325 
    Details
    ISSN: 1440-1703
    Keywords: body temperature ; brood parasitism ; cuckoo ; evolution ; telemetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Body temperatures of 11 bird species, including cuckoos, were measured in an artificial meteorological room. Ratios of change in body temperature to that in air temperature were thereby obtained for each species. Cuckoos demonstrate a remarkably high value, indicating a particularly low ability to regulate body temperature. Viewed in this light, the cuckoo's parasitic behavior is very likely an adaptation to overcome a physiological disadvantage. This in turn might be expected to reinforce delay in evolution of temperature homeostasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02347858
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  • 39
    Electronic Resource
    Electronic Resource
    Observations of chemical processing in the circumstellar environment (1995)
    Springer
    Astrophysics and space science 224 (1995), S. 81-84 
    Details
    ISSN: 1572-946X
    Keywords: Chemistry ; Depletions ; Shocks ; IRAS 05338-0624 ; NGC 1333 IRAS 4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High resolution interferometer and single-dish observations of young, deeply embedded stellar systems reveal a complex chemistry in the circumstellar environments of low to intermediate mass stars. Depletions of gas-phase molecules, grain mantle evaporation, and shock interactions actively drive chemical processes in different regions around young stars. We present results for two systems, IRAS 05338-0624 and NGC 1333 IRAS 4, to illustrate the behavior found and to examine the physical processes at work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00667826
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  • 40
    Electronic Resource
    Electronic Resource
    Identification of a novel moth sex pheromone inEriocrania cicatricella (Zett.) (Lepidoptera: Eriocraniidae) and its phylogenetic implications (1995)
    Springer
    Journal of chemical ecology 21 (1995), S. 29-43 
    Details
    ISSN: 1573-1561
    Keywords: Eriocrania cicatricella ; Eriocrania sparrmannella ; Eriocraniidae ; Lepidoptera ; sex pheromone ; EAG ; GC-EAD ; mass spectrometry ; synthesis ; evolution ; (Z)-4-hepten-2-one ; (2R)-heptan-2-ol ; (2R)-(Z)-4-hepten-2-ol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Extracts from different body parts of adult femaleEriocrania cicatricella (Zett.) were tested for electrophysiological activity on conspecific male antennae. Extracts from the Vth abdominal segment, containing a pair of exocrine glands, elicited the largest electroantennographic response when compared to extracts of other body parts. Female extracts were analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). The EAD active peaks were identified as (Z)-4-hepten-2-one, (2R)-heptane-2-ol, and (2R)-(Z)-4-hepten-2-ol by coinjection on a gas chromatography and by comparison of mass spectra with those of synthetic standards. In field tests, a blend of these three pheromone components was highly attractive to conspecific males, and a subtractive assay confirmed that the unsaturated alcohol is the major pheromone component, whereas no definite behavioral activity could be assigned to the ketone or the saturated alcohol. A bait containing the two alcohols withS-configuration was attractive to maleE. sparrmannella (Bosc), whereas no males ofE. cicatricella were found in these traps. The sex pheromone compounds inE. cicatricella are chemically similar to pheromones reported in Trichoptera and they are produced in homologous glands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033660
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  • 41
    Electronic Resource
    Electronic Resource
    Regulation of apoptosis in immune cells (1995)
    Springer
    Journal of clinical immunology 15 (1995), S. 1-16 
    Details
    ISSN: 1573-2592
    Keywords: Apoptosis ; T cells ; Nur77 ; DNase ; therapy ; oncogenes ; fas ; Fas ligand ; autoimmune disease ; aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01489485
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  • 42
    Electronic Resource
    Electronic Resource
    Allozymic characterization and evolutionary relationships in the BrazilianAkodon cursor species group (Rodentia-Cricetidae) (1995)
    Springer
    Biochemical genetics 33 (1995), S. 283-295 
    Details
    ISSN: 1573-4927
    Keywords: Akodon ; Cricetidae rodents ; genetic diversity ; biochemical polymorphism ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The present study involved an electrophoretic survey of 22 protein loci in 269 individuals belonging to three species of the genusAkodon, A. aff.cursor (2n=16),A. cursor (2n=14/15), andA. montensis (2n=24/25/26), collected in Eastern Brazil. The joint results of gene diversity, genetic distances, phenetic analyses, and phylogenetic trees suggested thatA. aff.cursor has recently separated fromA. cursor and that the three species have experienced a recent chromosomal divergence followed by low allozyme differentiation. These data are in agreement with their classification as sibling species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553809
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  • 43
    Electronic Resource
    Electronic Resource
    Amino acid sequence of the ribosomal protein HS23 from the halophilicHaloarcula marismortui and homology studies to other ribosomal proteins (1995)
    Springer
    The protein journal 14 (1995), S. 189-195 
    Details
    ISSN: 1573-4943
    Keywords: Ribosomal proteins ; protein sequencing ; evolution ; Haloarcula marismortui
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The ribosomal protein HS23 from the 30S subunit of the extreme halophilicHaloarcula marismortui, belonging to the group of archaea, was isolated either by RP-HLPLC or two-dimensional polyacrylamide gel electrophoresis. The complete amino acid sequence was determined by automated N-terminal microsequencing. The protein consists of 123 residues with a corresponding molecular mass of 12,552 Da as determined by electrospray mass spectroscopy; the pI is 11.04. Homology studies reveal similarities to the eukaryotic ribosomal protein S8 fromHomo sapiens, Rattus norvegicus, Leishmania major, andSaccharomyces cerevisiae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01886759
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  • 44
    Electronic Resource
    Electronic Resource
    Molecular cloning, characterization and expression analysis of two catalase isozyme genes in barley (1995)
    Springer
    Plant molecular biology 29 (1995), S. 1005-1014 
    Details
    ISSN: 1573-5028
    Keywords: evolution ; genome mapping ; isozymes ; oxygen radicals ; powdery mildew
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Clones representing two distinct barley catalase genes, Cat1 and Cat2, were found in a cDNA library prepared from seedling polysomal mRNA. Both clones were sequenced, and their deduced amino acid sequences were found to have high homology with maize and rice catalase genes. Cat1 had a 91% deduced amino acid sequence identity to CAT-1 of maize and 92% to CAT B of rice. Cat2 had 72 and 79% amino acid sequence identities to maize CAT-2 and-3 and 89% to CAT A of rice. Barley, maize or rice isozymes could be divided into two distinct groups by amino acid homologies, with one group homologous to the mitochondria-associated CAT-3 of maize and the other homologous to the maize peroxisomal/glyoxysomal CAT-1. Both barley CATs contained possible peroxisomal targeting signals, but neither had favorable mitochondrial targeting sequences. Cat1 mRNA occurred in whole endosperms (aleurones plus starchy endosperm), in isolated aleurones and in developing seeds, but Cat2 mRNA was virtually absent. Both mRNAs displayed different developmental expression patterns in scutella of germinating seeds. Cat2 mRNA predominated in etiolated seedling shoots and leaf blades. Barley genomic DNA contained two genes for Cat1 and one gene for Cat2. The Cat2 gene was mapped to the long arm of chromosome 4, 2.9 cM in telomeric orientation from the mlo locus conferring resistance to the powdery mildew fungus (Erysiphe graminis f.sp. hordei).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014973
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  • 45
    Electronic Resource
    Electronic Resource
    Isolation, expression, and evolution of the gene encoding mitochondrial elongation factor Tu in Arabidopsis thaliana (1995)
    Springer
    Plant molecular biology 29 (1995), S. 1057-1070 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis ; EF-Tu ; evolution ; gene families ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have characterized a second nuclear gene (tufM) in Arabidopsis thaliana that encodes a eubacterial-like protein synthesis elongation factor Tu (EF-Tu). This gene does not closely resemble the previously described Arabidopsis nuclear tufA gene, which encodes the plastid EF-Tu, and does not contain sequence elements found in all cyanobacterial and plastid tufA genes. However, the predicted amino acid sequence includes an N-terminal extension which resembles an organellar targeting sequence and shares three unique sequence elements with mitochondrial EF-Tu's, from Saccharomyces cerevisiae and Homo sapiens, suggesting that this gene encodes the Arabidopsis mitochondrial EF-Tu. Consistent with this interpretation, the gene is expressed at a higher level in flowers than in leaves. Phylogenetic analysis confirms the mitochondrial character of the sequence and indicates that the human, yeast, and Arabidopsis tufM genes have undergone considerably more sequence divergence than their cytoplasmic counterparts, perhaps reflecting a cross-compartmental acceleration of gene evolution for components of the mitochondrial translation apparatus. As previously observed for tufA, the tufM gene is present in one copy in Arabidopsis but in several copies in other species of crucifers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014977
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  • 46
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    Electronic Resource
    Cloning of the amphibolic Calvin cycle/OPPP enzyme d-ribulose-5-phosphate 3-epimerase (EC 5.1.3.1) from spinach chloroplasts: functional and evolutionary aspects (1995)
    Springer
    Plant molecular biology 29 (1995), S. 1279-1291 
    Details
    ISSN: 1573-5028
    Keywords: carbon fixation ; oxidative pentose phosphate pathway ; chloroplasts ; evolution ; endosymbiosis ; isoenzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Exploiting the differential expression of genes for Calvin cycle enzymes in bundle-sheath and mesophyll cells of the C4 plant Sorghum bicolor L., we isolated via subtractive hybridization a molecular probe for the Calvin cycle enzyme d-ribulose-5-phosphate 3-epimerase (R5P3E) (EC 5.1.3.1), with the help of which several full-size cDNAs were isolated from spinach. Functional identity of the encoded mature subunit was shown by R5P3E activity found in affinity-purified glutatione S-transferase fusions expressed in Escherichia coli and by three-fold increase of R5P3E activity upon induction of E. coli overexpressing the spinach subunit under the control of the bacteriophage T7 promoter, demonstrating that we have cloned the first functional ribulose-5-phosphate 3-epimerase from any eukaryotic source. The chloroplast enzyme from spinach shares about 50% amino acid identity with its homologues from the Calvin cycle operons of the autotrophic purple bacteria Alcaligenes eutrophus and Rhodospirillum rubrum. A R5P3E-related eubacterial gene family was identified which arose through ancient duplications in prokaryotic chromosomes, three R5P3E-related genes of yet unknown function have persisted to the present within the E. coli genome. A gene phylogeny reveals that spinach R5P3E is more similar to eubacterial homologues than to the yeast sequence, suggesting a eubacterial origin for this plant nuclear gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020468
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  • 47
    Electronic Resource
    Electronic Resource
    Ribonuclease P from plant nuclei and photosynthetic organelles (1995)
    Springer
    Molecular biology reports 22 (1995), S. 139-145 
    Details
    ISSN: 1573-4978
    Keywords: chloroplast ; cyanelle ; evolution ; pre-tRNA processing ; ribozyme ; wheat germ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract RNase P consists of both protein and RNA subunits in all organisms and organelles investigated so far, with the exception of chloroplasts and plant nuclei where no enzyme-associated RNA has been detected to date. Studies on substrate specificity revealed that cleavage by plant nuclear RNase P is critically dependent on a complete and intact structure of the substrate. No clearcut answer is yet possible regarding the order of processing events at the 5′ or 3′ end of tRNAs in the case of nuclear or chloroplast processing enzymes. RNase P from a phylogenetically ancient photosynthetic organelle will be discussed in greater detail: The enzyme from theCyanophora paradoxa cyanelle is the first RNase P from a photosynthetic organelle which has been shown to contain an essential RNA subunit. This RNA is strikingly similar to its counterpart from cyanobacteria, yet it lacks catalytic activity. Properties of the holoenzyme suggest an intermediate position in RNA enzyme evolution, with an eukaryotic-type, inactive RNA and a prokaryotic-type small protein subunit. The possible presence of an RNA component in RNase P from plant nuclei and modern chloroplasts will be discussed, including a critical evaluation of some criteria that have been frequently applied to elucidate the subunit composition of RNase P from different organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00988719
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  • 48
    Electronic Resource
    Electronic Resource
    Evolution of the Group 1 late embryogenesis abundant (Lea) genes: analysis of the Lea B19 gene family in barley (1995)
    Springer
    Plant molecular biology 28 (1995), S. 1039-1054 
    Details
    ISSN: 1573-5028
    Keywords: ABA-inducible genes ; coding region repeats ; embryo-specific gene family ; evolution ; Hordeum vulgare L. ; phylogenetic analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The highly conserved Group 1 late embryogenesis abundant (Lea) genes are present in the genome of most plants as a gene family. Family members are conserved along the entire coding region, especially within the extremely hydrophilic internal 20 amino acid motif, which may be repeated. Cloning of Lea Group 1 genes from barley resulted in the characterization of four family members named B19.1, B19.1b, B19.3 and B19.4 after the presence of this motif 1, 1, 3 and 4 times in each gene, respectively. We present here the results of comparative and evolutionary analyses of the barley Group 1 Lea gene family (B19). The most important findings resulting from this work are (1) the tandem clustering of B19.3 and B19.4, (2) the spatial conservation of putative regulatory elements between the four B19 gene promoters, (3) the determination of the relative ‘age’ of the gene family members and (4) the ‘chimeric’ nature of B19.3 and B19.4, reflecting a cross-over or gene-conversion event in their common ancestor. We also show evidence for the presence of one or two additional expressed B19 genes in the barley genome. Based on our results, we present a model for the evolution of the family in barley, including the 20 amino acid motif. Comparisons of the relatedness between the barley family and all other known Group 1 Lea genes using maximum parsimony (PAUP) analysis provide evidence for the time of divergence between the barley genes containing the internal motif as a single copy and as a repeat. The PAUP analyses also provide evidence for independent duplications of Group 1 genes containing the internal motif as a repeat in both monocots and dicots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00032665
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  • 49
    Electronic Resource
    Electronic Resource
    Evolutionary origin of expandable G-C-rich triplet repeat DNA sequences (1995)
    Springer
    Biochemical genetics 33 (1995), S. 173-181 
    Details
    ISSN: 1573-4927
    Keywords: fragile-X DNA systems ; expandable triplet repeats ; dynamic mutations ; conserved genetic domains ; evolution ; heritable disease mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A model explaining properties exhibited by fragile-X DNA systems arises from observations that time-dependent base substitutions are expressed at G-C sites but not at A–T sites (Biochem. Genet.32:383, 1994). [CGG]n sequences are classified as most sensitive to evolutionary base substitution processes involving time-dependent populating of G-C sites with enol-imine states having enhanced stability. Increased density of these states in oocyte DNA would introduce a ground-state collapse double-helix of reduced energy that would inhibit strand separation by the replicase. Evolutionarily altered G′ in CG′G triplets allows CG′G to be transcribed as CTG, an initiation codon. And this will cause reinitiation of DNA synthesis, thereby adding additional CGG units to the collapsed double helix. This situation would not occur in slower-evolving male haploid DNA that replicates frequently.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00554729
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  • 50
    Electronic Resource
    Electronic Resource
    Allozymic characterization and evolutionary relationships in the BrazilianAkodon cursor species group (Rodentia-Cricetidae) (1995)
    Springer
    Biochemical genetics 33 (1995), S. 283-295 
    Details
    ISSN: 1573-4927
    Keywords: Akodon ; Cricetidae rodents ; genetic diversity ; biochemical polymorphism ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The present study involved an electrophoretic survey of 22 protein loci in 269 individuals belonging to three species of the genusAkodon, A. aff.cursor (2n=16),A. cursor (2n=14/15), andA. montensis (2n=24/25/26), collected in Eastern Brazil. The joint results of gene diversity, genetic distances, phenetic analyses, and phylogenetic trees suggested thatA. aff.cursor has recently separated fromA. cursor and that the three species have experienced a recent chromosomal divergence followed by low allozyme differentiation. These data are in agreement with their classification as sibling species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02399928
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  • 51
    Electronic Resource
    Electronic Resource
    The primary structure ofHarpalus rufipes 5S ribosomal RNA (1995)
    Springer
    Molecular biology reports 21 (1995), S. 165-167 
    Details
    ISSN: 1573-4978
    Keywords: 5S ribosomal RNA ; Harpalus rufipes ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nucleotide sequence of 5S ribosomal RNA from the beetleHarpalus rufipes was determined and compared with primary structures of other insect 5S rRNAs. Sequence differences between two beetle 5S rRNAs may represent phylogenetic markers specific for two groups of Coleoptera — Adephaga and Polyphaga. Analysis of all insect sequences using parsimony allowed us to infer a phylogenetic tree of insects, which is consistent with morphological and paleobiological data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00997239
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  • 52
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    Electronic Resource
    The myrosinase gene family in Arabidopsis thaliana: gene organization, expression and evolution (1995)
    Springer
    Plant molecular biology 27 (1995), S. 911-922 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis ; evolution ; expression ; genomic clone ; in situ hybridization ; myrosinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1.) is in Brassicaceae species such as Brassica napus and Sinapis alba encoded by two differentially expressed gene families, MA and MB, consisting of about 4 and 10 genes, respectively. Southern blot analysis showed that Arabidopsis thaliana contains three myrosinase genes. These genes were isolated from a genomic library and two of them, TGG1 and TGG2, were sequenced. They were found to be located in an inverted mode with their 3′ ends 4.4 kb apart. Their organization was highly conserved with 12 exons and 11 short introns. Comparison of nucleotide sequences of TGG1 and TGG2 exons revealed an overall 75% similarity. In contrast, the overall nucleotide sequence similarity in introns was only 42%. In intron 1 the unusual 5′ splice border GC was used. Phylogenetic analyses using both distance matrix and parsimony programs suggested that the Arabidopsis genes could not be grouped with either MA or MB genes. Consequently, these two gene families arose only after Arabidopsis had diverged from the other Brassicaceae species. In situ hybridization experiments showed that TGG1 and TGG2 expressing cells are present in leaf, sepal, petal, and gynoecium. In developing seeds, a few cells reacting with the TGG1 probe, but not with the TGG2 probe, were found indicating a partly different expression of these genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00037019
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    Two copies of a DNA element, ‘Wendy’, in the chloroplast chromosome of Chlamydomonas reinhardtii between rearranged gene clusters (1995)
    Springer
    Plant molecular biology 29 (1995), S. 63-80 
    Details
    ISSN: 1573-5028
    Keywords: evolution ; Chlamydomonas reinhardtii ; chloroplast ; site-specific recombination ; transcription ; transposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have characterized two copies of a 2.4 kb DNA element that we call ‘Wendy’, in the chloroplast chromosome of Chlamydomonas reinhardtii. The two copies of Wendy reside in different single-copy regions at opposite positions in the chloroplast genome. Like many mobile DNA elements, both copies of Wendy are bordered by inverted repeats and contain several additional degenerate copies of these repeat sequences in direct or inverted orientation. In addition, four basepairs are repeated in direct orientation. Two major open reading frames (ORFs) are predicted from the DNA sequence of Wendy I. These ORFs are co-transcribed from a promoter inside the element. The deduced amino acid sequence of the larger of these ORFs shares some weak similarities with sequence motifs of transposases and integrases of other mobile elements. Wendy II appears to be altered relative to Wendy I by point mutations and small deletions and insertions which destroy the ORFs. The leader sequence of the Wendy transcript is nearly identical with the leader sequence of the rbcL transcript of C. reinhardtii, but not of C. moewusii (where the complete Wendy was also undetectable). Furthermore, both copies of Wendy are bracketed by gene clusters that are separated in C. reinhardtii but are contiguous in C. moewusii where they exist in an inverted orientation compared with C. reinhardtii. Wendy was not found in any of the completely sequenced chloroplast genomes of rice, tobacco, pine, Euglena or Marchantia, nor in any other GenBank entry. Our results suggest that Wendy has invaded C. reinhardtii after divergence from other species. Subsequent Wendy-dependent illegitimate homologous or site-specific recombination events or both may have contributed to scrambling of the C. reinhardtii chloroplast genome relative to genomes of other species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019119
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    Detection of DNA strand breaks associated with apoptosis in human brain tumors (1995)
    Springer
    Virchows Archiv 427 (1995), S. 175-179 
    Details
    ISSN: 1432-2307
    Keywords: Brain tumor ; Apoptosis ; DNA strand breaks ; MIB-1 antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Apoptosis occurs spontaneously in a wide variety of enoplasms. However, it is difficult to detect apoptotic cells in routine histological sections because the cells undergoing apoptosis die singly and are then rapidly phagocytosed. Since DNA fragmentation is an important hallmark of apoptosis, visualization of DNA strand breaks in tissue sections provides the means for readily identifying apoptotic cells in situ. We have applied an in situ DNA strand break staining procedure for the quantitative estimation of apoptotic cells in surgical specimens of 62 different brain tumours. Positively stained apoptotic cells were observed in 25 (40.3%) cases and their percentage (apoptotic index) ranged from 0.1 to 8.9. Both fragmented and condensed nuclei of apoptotic cells and apoptotic bodies were stained. In addition, we assessed the proliferative activity of each specimen by immunostaining with the MIB-1 antibody (MIB-1 index) which detects the cell cycle phase-dependent Ki-67 antigen. Brain tumours with higher MIB-1 indices showed a tendency to higher apoptotic indices. The results of this study indicate that apoptosis occurs spontaneously in various brain tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196523
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    Cell deletion by apoptosis during regression of rat parotid sialadenosis (1995)
    Springer
    Virchows Archiv 427 (1995), S. 181-186 
    Details
    ISSN: 1432-2307
    Keywords: Isoproterenol ; Apoptosis ; Rat ; Parotid ; Sialadenosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Enlargement of the rat parotid salivary glands was induced by repeated administration of isoproterenol. Mean wet weights of the treated glands increased steadily to 240% of control values. Following withdrawal of the drug, quantitative histological techniques were used to investigate the balance between hypertrophy, hyperplasia and apoptosis. The volume occupied by acinar cells relative to the total gland volume together with cytoplasmic|:|nuclear area ratios as measures of hypertrophy increased during the early experimental period. Similarly, serous acinar cell mitotic counts increased, indicating that hyperplasia had occurred. Apoptosis was demonstrated at light microscopical level to be the main mechanism for cell deletion as the glands returned to normal size and weight. The results indicate that hypertrophy and hyperplasia of serous acinar cells contribute to isoproterenol-induced sialadenosis. The experimental animal model demonstrates that these proliferative changes are completed by 48 h and thereafter are balanced by apoptosis as the glands recover their normal size and weight.
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    URL: http://dx.doi.org/10.1007/BF00196524
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    Effect of age on NADPH-diaphorase-containing myenteric neurones of rat ileum and proximal colon (1995)
    Springer
    Cell & tissue research 279 (1995), S. 379-383 
    Details
    ISSN: 1432-0878
    Keywords: NADPH-diaphorase ; Myenteric plexus-Ileum ; Proximal colon ; Age ; Programmed cell survival and cell death ; Apoptosis ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The effect of age on the distribution of NADPH-diaphorase-containing neurones was investigated in the myenteric plexus of ileum and proximal colon of embryonic day-19 rats, as well as in rats at postnatal day 4, 6 months and 26 months. The mean percentage of NADPH-diaphorase-stained neurones per ganglion was established using protein gene product 9.5 (protein found in most if not all neurones)-immunostained neurones as 100%. The results revealed that there was a significant relative increase in NADPH-diaphorase-positive neurones with increasing age in the myenteric plexus of proximal colon with nearly all protein gene product 9.5-immunoreactive neurones staining for NADPH-diaphorase in 26-month-old rats. This was in marked contrast with the ileum, where no significant relative increase in NADPH-diaphorase-positive neurones was seen in aged rats. The implications of these findings in relation to programmed cell survival and cell death are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318495
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    Immunolocalization of a gonadotropin-releasing hormone receptor site in murine endometrium that mediates apoptosis (1995)
    Springer
    Cell & tissue research 282 (1995), S. 527-529 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Gonadotropin-releasing hormone receptor ; Endometrium ; Apoptosis ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Circumstantial evidence from a previous study indicated that antibodies generated against a synthetic N-terminal extracellular domain mouse pituitary gonadotropin-releasing hormone (GnRH) receptor peptide acted directly on the murine uterus affecting endometrial regression. Affinity-purified polyclonal sheep antibodies were used to assess tissue-specificity of antibody reactions in diestrous mice. Antibody binding was localized by immunofluorescence staining to anterior pituitary gland and endometrium. Ovary, brain, liver, kidneys, heart, lungs, spleen, gastrointestinal tract, adrenal glands, thymus, thyroid gland, muscle, and adipose were unreactive. Fragmented deoxyribonucleic acid, a marker of programmed cell death/apoptosis, was detected by digoxigenin labeling-immunoperoxidase in endometrial (but not pituitary) glands of animals injected with antipeptide antibodies or native ligand. It appears that luteal phase endometrium of mice expresses a GnRH receptor moiety that is coupled to a cell death (endonuclease) transduction pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050505
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    Effect of age on NADPH-diaphorase-containing myenteric neurones of rat ileum and proximal colon (1995)
    Springer
    Cell & tissue research 279 (1995), S. 379-383 
    Details
    ISSN: 1432-0878
    Keywords: Key words: NADPH-diaphorase ; Myenteric plexus ; Ileum ; Proximal colon ; Age ; Programmed cell survival and cell death ; Apoptosis ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The effect of age on the distribution of NADPH-diaphorase-containing neurones was investigated in the myenteric plexus of ileum and proximal colon of embryonic day-19 rats, as well as in rats at postnatal day 4, 6 months and 26 months. The mean percentage of NADPH-diaphorase-stained neurones per ganglion was established using protein gene product 9.5(protein found in most if not all neurones)-immunostained neu- rones as 100%. The results revealed that there was a significant relative increase in NADPH-diaphorase-positive neurones with increasing age in the myenteric plexus of proximal colon with nearly all protein gene product 9.5-immunoreactive neurones staining for NADPH-diaphorase in 26-month-old rats. This was in marked contrast with the ileum, where no significant relative increase in NADPH-diaphorase-positive neurones was seen in aged rats. The implications of these findings in relation to programmed cell survival and cell death are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050294
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    Electronic Resource
    Immunolocalization of a gonadotropin-releasing hormone receptor site in murine endometrium that mediates apoptosis (1995)
    Springer
    Cell & tissue research 282 (1995), S. 527-529 
    Details
    ISSN: 1432-0878
    Keywords: Gonadotropin-releasing hormone receptor ; Endometrium ; Apoptosis ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Circumstantial evidence from a previous study indicated that antibodies generated against a synthetic N-terminal extracellular domain mouse pituitary gonadotropin-releasing hormone (GnRH) receptor peptide acted directly on the murine uterus affecting endometrial regression. Affinity-purified polyclonal sheep antibodies were used to assess tissue-specificity of antibody reactions in diestrous mice. Antibody binding was localized by immunofluorescence staining to anterior pituitary gland and endometrium. Ovary, brain, liver, kidneys, heart, lungs, spleen, gastrointestinal tract, adrenal glands, thymus, thyroid gland, muscle, and adipose were unreactive. Fragmented deoxyribonucleic acid, a marker of programmed cell death/apoptosis, was detected by digoxigenin labeling-immunoperoxidase in endometrial (but not pituitary) glands of animals injected with antipeptide antibodies or native ligand. It appears that luteal phase endometrium of mice expresses a GnRH receptor moiety that is coupled to a cell death (endonuclease) transduction pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318886
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    Apoptosis in lactating and involuting mouse mammary tissue demonstrated by nick-end DNA labelling (1995)
    Springer
    Cell & tissue research 281 (1995), S. 413-419 
    Details
    ISSN: 1432-0878
    Keywords: Apoptosis ; Mammary gland ; Lactation ; Involution ; DNA laddering ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Mammary involution after cessation of milk removal is associated with extensive loss of secretory epithelial cells. Ultrastructural changes and the appearance of oligonucleosomal DNA laddering in ethidium bromide-stained gels indicates that cell loss during involution occurs by apoptosis. In this study, a technique for nick end-labelling of genomic DNA with radiolabelled deoxynucleotide has been used to monitor the induction of programmed cell death in mice after litter removal at peak lactation. This technique proved more sensitive than conventional ethidium bromide staining, and results suggested that apoptosis was induced rapidly by milk stasis, before extensive tissue re-modelling had begun. Oligonucleosomal DNA laddering on agarose gels was detected within 24 h of milk stasis, and increased progressively for at least 4 days. Nick-end labelling also detected laddering before litter removal, suggesting that programmed cell death is a normal feature of the lactating tissue. The DNA end-labelling technique was also adapted for in situ visualisation of apoptotic cells in tissue sections. By this criterion, apoptotic cells were identified in both the secretory epithelium lining the alveoli of the gland and, increasingly with prolonged milk stasis, amongst those sloughed into the alveolar lumen. The results demonstrate the utility of these techniques for study of mammary cell death and suggest that, whilst apoptosis is rapidly induced by milk stasis, it is also a normal physiological event in the lactating mammary gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00417859
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    The pollinium ofLoroglossum hircinum (Orchidaceae) between pollination and pollen tube emission (1995)
    Springer
    Plant systematics and evolution 196 (1995), S. 141-151 
    Details
    ISSN: 1615-6110
    Keywords: Orchidaceae ; Loroglossum hircinum ; Compound pollen ; pollinium ; pollen tubes ; generative cell ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The structure of the massulae composing the pollinium ofLoroglossum hircinum was studied before pollination and 12 and 24 hours afterwards. The grains are grouped in tetrads closely packed in massulae. The exine is only present on the outside of the massulae. The intine consists of two layers: a compact layer surrounding the pollen grain and a looser layer surrounding the pollen grain and a looser layer surrounding the tetrad. Twelve hours after pollination, pollen volume and the space between the tetrads increase due to vacuolization. Twenty-four hours after pollination, pollen volume and tetrad spacing are higher due to vacuolization and some grains have emitted pollen tubes. Pollen growth due to vacuole formation, and the absence of common walls between adjacent tetrads lead to crumbling of the massulae. The mature pollen grain does not have apertures: the site of pollen tube emission is determined after pollination. The first grains to germinate are those in the centre of the massula. The vegetative cell nucleus is the first to enter the pollen tube; the generative cell elongates and undergoes the second haploid mitosis shortly after entering the pollen tube.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00982955
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    Genetic relationships between peanut and wild species ofArachis sect.Arachis (Fabaceae): Evidence from RAPDs (1995)
    Springer
    Plant systematics and evolution 198 (1995), S. 167-178 
    Details
    ISSN: 1615-6110
    Keywords: Fabaceae ; Arachis ; Arachis hypogaea ; RAPD ; systematics ; evolution ; germplasm resources
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-six accessions of wildArachis species and domesticated peanuts,A. hypogaea, introduced from South America were analyzed for random amplified polymorphic DNA (RAPD). The objective of the study was to investigate inter- and intraspecific variation and affinities among species of sect.Arachis which have been proposed as possible progenitors for the domesticated peanut. Ten primers resolved 132 DNA bands which were useful for separating species and accessions. The most variation was observed among accessions ofA. cardenasii andA. glandulifera whereas the least amount of variation was observed inA. hypogaea andA. monticola. The two tetraploid species could not be separated by using RAPDs.Arachis duranensis was most closely related to the domesticated peanut and is believed to be the donor of the A genome. The data indicated thatA. batizocoi, a species previously hypothesized to contribute the B genome toA. hypogaea, was not involved in its evolution. The investigation showed that RAPDs can be used to analyze both inter- and intraspecific variation in peanut species. Southern hybridization of RAPD probes to blots containing RAPD of theArachis species provided information on genomic relationships and revealed the repetitive nature of the amplified DNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984735
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    Induction of apoptosis in lymphoid cells by thiol-mediated oxidative stress (1995)
    Springer
    Protoplasma 184 (1995), S. 181-187 
    Details
    ISSN: 1615-6102
    Keywords: Antioxidants ; Apoptosis ; Glutathione ; N-Acetylcysteine ; Oxidation-reduction ; Thiols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In previous studies, oxidants such as hydrogen peroxide (H2O2) or hydroperoxy fatty acids were shown to induce apoptosis in the CEM human T cell line as demonstrated by the cleavage of cellular DNA into a ∼ 180-base pair “ladder”. Oxidant-induced DNA fragmentation was detectable within 3 h and inhibitable by various antioxidants. In the present study, apoptosis is shown to also be induced by the addition of low doses (0.1–3 mM) of N-acetyl-L-cysteine (NAC), reduced glutathione (GSH) or cysteine. By contrast, higher concentrations (≥10 mM) of the same thiols displayed a paradoxical lack of toxicity. Thiol-induced apoptosis was completely prevented by the addition of BAPTA-AM, an intracellular calcium chelator, or by simultaneous treatment with 5 mM pyruvate which forms a thiazolidine complex with sulfhydryl compounds. Catalase or glutathione peroxidase, but not Superoxide dismutase, protected the cells from thiol-induced apoptosis demonstrating a role for H2O2. The ability of thiol compounds to either evoke or prevent oxidative stress implies a unique role for these agents in the control of apoptosis in lymphoid cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276918
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    Mechanism of killing of HeLa cells by the antitumor sulfonylurea, N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea (LY 181984) (1995)
    Springer
    Protoplasma 184 (1995), S. 188-195 
    Details
    ISSN: 1615-6102
    Keywords: Antitumor sulfonylurea ; Apoptosis ; pH control ; Growth ; Hela cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The antitumor sulfonylureas appear to inhibit both mitochondrial activity in susceptible human colon lines and to inhibit the oxidation of NADH by isolated plasma membrane vesicles from HeLa cells. The results reported here describe the morphological appearance of HeLa cells treated with the antitumor sulfonylurea N-(4-methylphenylsulfonyl)-N′-(4-chlorophenyl)urea (LY181984). The cells remain viable for several days although the rate of increase in cell number is slowed especially at high concentrations of the drug. Cells become smaller with normal nuclei or maintain a normal size but contain multiple or enlarged nuclei. The morphological observations suggest that the drug may somehow interfere with the ability of the cells to enlarge following cytokinesis. Between 72 and 96 h, the cells begin to die. Cell death is accompanied by a condensed and fragmented appearance of the nuclear DNA as revealed by fluorescence microscopy with 4′,6-diamidino-2-phenylindole suggestive of apoptosis. Early transients in loss of pH control (4 min after sulfonylurea addition) and an increase in cytoplasmic calcium (4 h after sulfonylurea addition) were observed but were small and perhaps secondary to the mechanism responsible for the failure of the cells to grow and ensuing cell death.
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    URL: http://dx.doi.org/10.1007/BF01276919
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    How is a species kept together? (1995)
    Springer
    Biology and philosophy 10 (1995), S. 181-196 
    Details
    ISSN: 1572-8404
    Keywords: Biological species concept ; gene flow ; gene circulation ; Ernst Mayr ; stalemates ; typology ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Over the decades, there has been substantial empirical evidence showing that the unity of species cannot be maintained by gene flow. The biological species concept is inconclusive on this point. The suggestion is made that the unity of species is maintained rather by selection constantly spreading new alleles throughout the species, or bygene circulation. There is a lack in conceptual distinction between gene flow and gene circulation which lies at the heart of the problem. The concept of gene circulation also sheds some new light on the problem of typology and on such a broad concept as evolution. A new species definition is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00852244
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    A (not-so-radical) solution to the species problem (1995)
    Springer
    Biology and philosophy 10 (1995), S. 339-356 
    Details
    ISSN: 1572-8404
    Keywords: Species ; lineage ; individual ; class ; evolution ; organism ; population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract What are species? One popular answer is that species are individuals. Here I develop another approach to thinking about species, an approach based on the notion of a lineage. A lineage is a sequence of reproducing entities, individuated in terms of its components. I argue that one can conceive of species as groups of lineages, either organism lineages or population lineages. Conceiving of species as groups of lineages resolves the problems that the individual conception of species is supposed to resolve. It has added the virtue of focusing attention on the characteristic of species that is most relevant to understanding their role in evolutionary processes, namely, the lineage structure of species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00852472
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    Viability explanation (1995)
    Springer
    Biology and philosophy 10 (1995), S. 435-457 
    Details
    ISSN: 1572-8404
    Keywords: Functional explanation ; morphology ; ethology ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract This article deals with a type of functional explanation, viability explanation, that has been overlooked in recent philosophy of science. Viability explanations relate traits of organisms and their environments in terms of what an individual needs to survive and reproduce. I show that viability explanations are neither causal nor historical and that, therefore, they should be accounted for as a distinct type of explanation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00857593
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    Are the different hypotheses on the emergence of life as different as they seem? (1995)
    Springer
    Biology and philosophy 10 (1995), S. 389-417 
    Details
    ISSN: 1572-8404
    Keywords: Catalysis ; chance ; determinism ; emergence of life ; evolution ; non-equilibrium thermodynamics ; panspermia ; protometabolism ; reduction ; RNA world ; self-organization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract This paper calls attention to a philosophical presupposition, coined here “the continuity thesis” which underlies and unites the different, often conflicting, hypotheses in the origin of life field. This presupposition, a necessary condition for any scientific investigation of the origin of life problem, has two components. First, it contends that there is no unbridgeable gap between inorganic matter and life. Second, it regards the emergence of life as a highly probable process. Examining several current origin-of-life theories. I indicate the implicit or explicit role played by the “continuity thesis” in each of them. In addition, I identify the rivals of the “thesis” within the scientific community — “the almost miracle camp.” Though adopting the anti-vitalistic aspect of the “continuity thesis”, this camp regards the emergence of life as involving highly improbable events. Since it seems that the chemistry of the prebiotic stages and of molecular self-organization processes rules out the possibility that life is the result of a “happy accident,” I claim that the “almost miracle” view implies in fact, a creationist position.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00857591
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    Apoptosis in CHO cell batch cultures: examination by flow cytometry (1995)
    Springer
    Cytotechnology 17 (1995), S. 1-11 
    Details
    ISSN: 1573-0778
    Keywords: Apoptosis ; programmed cell death ; CHO cells ; batch culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Chinese hamster ovary cells grown under conditions which are optimal for the production of a genetically engineered protein in batch culture, lose significant viability shortly after entering the stationary phase. This cell death was investigated morphologically and was found to be almost exclusively via apoptosi. Furthermore, cells were analyzed by flow cytometry using a fluorescent DNA end-labeling assay to label apoptotic cells, in conjunction with cell cycle analysis using propidium iodide. Apoptotic cells could be detected by this method, and by the radioactive end-labeling of extracted DNA, on all days of culture from day 1 to day 7; however, the degree of apoptotic cell death increased dramatically when the cells entered the stationary phase, rising to 50–60% of the total cell number at the termination of the culture. Flow cytometric analysis showed that the majority of cells underwent apoptosis whilst in G1/G0 and formed an apoptotic population with high DNA FITC end-labeling and hypodiploid propidium iodide binding. Additionally, the ability or inability to secrete specific protein products did not appear to interfere with the development of the apoptotic population with time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749215
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    Palaeolithic archaeology and the evolution of mind (1995)
    Springer
    Journal of archaeological research 3 (1995), S. 305-332 
    Details
    ISSN: 1573-7756
    Keywords: Palaeolithic archaeology ; evolution ; language ; intelligence ; social learning ; symbolism ; the Mind
    Source: Springer Online Journal Archives 1860-2000
    Topics: Archaeology
    Notes: Abstract This paper reviews recent archaeological studies concerning the evolution of mind. It is structured around four themes: language, intelligence, symbolism, and social learning. It includes reference to recent work in other disciplines that is either having, or likely to have, considerable impact on archaeological thought. The evolution of mind is a highly contentious subject, plagued by problems of definition and lacking an explicit methodology. This paper argues that the two most positive trends of recent work have been greater attempts at interdisciplinary studies and the integration of the study of cognition with that of hominid lifestyles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02232718
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    Interleukin-1β-converting enzyme and related proteases as potential targets in inflammation and apoptosis (1995)
    Springer
    Perspectives in drug discovery and design 2 (1995), S. 389-399 
    Details
    ISSN: 1573-9023
    Keywords: Interleukin-1β-converting enzyme ; Inflammation ; Apopain ; CPP32 ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Interleukin-1β-converting enzyme (ICE, EC 3.4.22.36) is the cysteine protease responsible for the production of interleukin-1β in monocytes. Since its discovery in 1989, this enzyme has been the subject of enthusiastic investigation because of the suspected role of this cytokine in the pathogenesis of inflammatory diseases such as rheumatoid arthritis. These studies have culminated in the purification and cloning of the enzyme, development of potent inhibitors, determination of its structure by X-ray crystallography and the development of knockout mice, which have confirmed an important role for this protease in inflammation. Late in 1993, the protease became the subject of further interest because of its homology to CED-3, the product of a gene required for programmed cell death in the nematodeC. elegans. It is now clear that ICE is the first identified member of a new cysteine protease family that includes CED-3 and at least four other human homologues. Although the extent to which ICE itself plays a role in mammalian apoptosis remains controversial, it is clear that at least one of these homologues, CPP32, is an important player. The recognition that members of this family play key biological roles in both inflammation and apoptosis, two extremely attractive targets for therapeutic intervention, has led to intense interest in these proteases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02172032
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  • 72
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    The role of metalloproteinases and their inhibitors in regulating mammary epithelial morphology and function in vivo (1995)
    Springer
    Perspectives in drug discovery and design 2 (1995), S. 401-411 
    Details
    ISSN: 1573-9023
    Keywords: ECM ; Proteinases ; Mammary gland ; Apoptosis ; Breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An intact basement membrane (BM) is essential for the proper function, differentiation and morphology of many epithelial cells. The disruption or loss of this BM occurs during normal development as well as in the disease state. To examine the importance of the BM during mammary gland development in vivo, we generated transgenic mice which inappropriately express autoactivating isoforms of the matrix metalloproteinase, stromelysin-1. The mammary glands from these mice are both functionally and morphologically altered throughout development. The mammary glands from virgin transgenic mice had supernumerary branches and showed precocious development of alveoli that expressed β-casein. During midpregnancy, the alveolar structures were collapsed and mouse mammary epithelial cells underwent apoptosis. We have now documented a dramatic incidence of breast tumors in several independent lines of these mice. These data suggest that overexpression of SL-1 and disruption of the BM may play a key role in mammary gland branching morphogenesis, apoptosis and breast cancer induction and progression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02172033
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  • 73
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    Genetic diversity, distributional barriers and rafting continents — more thoughts on the evolution of mangroves (1995)
    Springer
    Hydrobiologia 295 (1995), S. 167-181 
    Details
    ISSN: 1573-5117
    Keywords: mangrove ; Avicennia ; evolution ; fossils ; pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Without continental drift, the diversity and distribution of many species, including mangrove plants, would be very different today. First, there would be fewer pantropic genera and many more endemics. Second, their characteristics would not be as common and widespread as some are today. Continental drift has brought about the massive mixing and dispersal of genes in geologically recent times, greatly enhancing the evolutionary process; particularly for flowering plants — the angiosperms, which evolved during the period. Mangrove plants are comprised of approximately 70 species from 20 quite different angiosperm families. Most taxa are characterized by special physiological abilities and structural forms, enabling them to live in both seasonally fluctuating saline conditions, and water-saturated soils. Their occurrence is mostly tropical, perhaps because of harsh physiological conditions of intertidal habitats; but distributions of specific taxa do not fully concur with the idea of a completely tropical evolution, at least for some important species. At least one genus of mangrove tree, Avicennia, occurs around the world, chiefly in tropical estuarine habitats, although they also range into temperate latitudes, especially in the south. Around the world, there are no more than ten species of Avicennia recognised today, but their diagnostic determinants were inadequate prior to recent studies using both numerical analyses of morphological parameters and isozymes. Such analyses significantly reduced the number of apparent species, notably around Australia, and provided a basis for the revision of distributional records throughout the Indo West Pacific region. One species, A. marina, was found to be widespread and morphologically variable with genes divided into characteristic groupings of at least three geographic areas in the region. Based on these findings, there are several novel inferences to be made regarding the evolution of this genus. A western Gondwanan origin is proposed, with subsequent radiation of several taxa facilitated via the tectonic dispersal of southern continental fragments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029124
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  • 74
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    The evolution of groundwater Cladocera (1995)
    Springer
    Hydrobiologia 307 (1995), S. 69-74 
    Details
    ISSN: 1573-5117
    Keywords: groundwater ; evolution ; Cladocera ; Alona ; conserved species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cladocera occur in various types of groundwater, but are most common in the underflow of rivers. Numerous surface water species occasionally venture into groundwater; some chydorids are more common in groundwaters than in surface waters; at least three groups within Alona, finally, have evolved exclusive groundwater species. The latter show few obvious adaptations to the subterranean habitat, except loss of an eye or total blindness. Some, however, have conserved an array of primitive characters (e.g. on the end-claw of the postabdomen, and the setation of the valve rims) which suggest that the physical protection and relative constancy of the hyporheic has permitted the survival of some ancient taxa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00031998
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    An isolated population of fourhorn sculpins (Myoxocephalus quadricornis, family Cottidae) in a hypersaline high arctic Canadian lake (1995)
    Springer
    Hydrobiologia 312 (1995), S. 27-35 
    Details
    ISSN: 1573-5117
    Keywords: mining impacts ; sculpins ; cephalic spines ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Freshwater sculpins probably evolved from marine ancestors which entered bodies of water such as proglacial lakes or lakes which were gradually isolated from the sea by isostatic rebound. Sculpins in fresh water lakes (Myoxocephalus thompsoni [Girard]) lack cephalic horns and live well below a depth of 10 m. Those in the sea (Myoxocephalus quadricornis [Linnaeus]) typically live above 10 m and possess a well developed set of four cephalic horns. The sculpins in Garrow Lake, North West Territories, are intermediate between the marine and fresh water forms with respect to their depth distributions and their cephalic horns (spines). As a consequence, Garrow Lake, which separated from the sea some 3000 years ago, serves as an excellent ‘laboratory’ for studying evolutionary changes in this sculpin. The age of the lake was based on carbon-14 dates of the fossil pelecypods from raised beaches around the lake and from observations of rates of isostatic rebound in the area as reported by Dickman & Ouellet 1983 and Pagé et al. 1984. During the last 3000 years, the surface waters of Garrow Lake have freshened and its sculpins have apparently adapted to this top down freshening by occupying a depth where the salinity of the lake approaches that of sea water. As a result, the sculpin population in Garrow Lake lives deeper than the sculpin population in the nearby Garrow Bay. Thus, the deeper dwelling Garrow Lake sculpins appear to be less vulnerable to avian predation than their shallow water dwelling marine ancestors. It is hypothesized that reduced avian predation of the Garrow Lake sculpin population is associated with the observed reduction in their cephalic horns which impart a certain degree of disruptive colouration and disruptive pattern outline allowing the shallow dwelling marine species to blend in with its background in a manner which appears to make it less visible to avian predators. It is unfortunate that the three thousand year old Garrow Lake sculpin population is now endangered by mine tailings entering the lake from the nearby Cominco Ltd. mine. The entire food chain of the lake appears to have been severely impacted by lead and zinc mine tailings entering Garrow Lake at a rate of 100 metric tonnes per hour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018884
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    Phylogeny and adaptive radiation within the Anomopoda: a preliminary exploration (1995)
    Springer
    Hydrobiologia 307 (1995), S. 57-68 
    Details
    ISSN: 1573-5117
    Keywords: Anomopoda ; evolution ; phylogeny ; adaptive radiation ; morphology ; ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distinctness of the Anomopoda and the polyphyletic nature of the so-called Cladocera are emphasized. An attempt is made to reconstruct the ancestral anomopod, which probably lived in Palaeozoic times. This task is facilitated by the availability of detailed information on extant forms, which includes functional as well as purely morphological considerations and enables us to understand the means whereby complex mechanisms were transformed during evolution. Comparative studies on the ecology and habits of extant forms also throw light on the probable way of life of the ancestral anomopod. Adaptive radiation within the Anomopoda is briefly surveyed and an outline of the suggested phylogeny of the order is indicated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00031997
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  • 77
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    The late Cenozoic ampullariidae (mollusca, gastropoda) of the Albertine Rift Valley (Uganda-Zaire) (1995)
    Springer
    Hydrobiologia 316 (1995), S. 1-32 
    Details
    ISSN: 1573-5117
    Keywords: Africa ; autapomorphic characters ; convergence ; evolution ; freshwaters snails ; Lanistes ; Mollusca ; palaeolimnology ; palaeontology ; Pila ; predator/prey coevolution ; riftlakes ; taxonomy ; punctuated equilibrium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Albertine Rift Valley (Uganda-Zaire) contains vast sedimentary sequences of late Cenozoic age. They were deposited in an extensive riftlake, Lake Obweruka, which existed from c. 8 Ma to 2.5 Ma and was comparable in size and depth to the present L. Tanganyika. Many freshwater molluscs that occur in these lacustrine deposits are characterised by their aberrant shell morphology, their extreme ornamentation and general form, making them resemble marine species. This convergence, rare in freshwater molluscs, is called thalassoidism and extreme ornamentation in marine as well as in freshwater molluscs is considered to be the result of a gradual process of prey/predator coevolution. In the present paper the Albertine representants of the ampullariid genera Lanistes and Pila, most of which are new to science, are taxonomically described and their phylogenetic relation, based upon apomorphic characters, is given. In addition the evolutionary history of these freshwater snails in the basin has been reconstructed. In the pre-riftlake environment 3 species of Lanistes occurred, with no special shell adaptations against predation. After the formation of a riftlake, 2 of these, colonising the new lacustrine ecospace, changed morphologically and radiated. The 3 derived lines show minor adaptations against predation. After the extinction of the dominant Lanistes species group around 6 Ma, the sole surviving lacustrine Lanistes suddenly radiates, the ancestral line persisting next to the 3 new daughter lines. This second morphological shift is spectacular as it produces shells with distinct thalassoid features. All the Lanistes species of L. Obweruka became extinct during a cataclysmic event around 4.5 Ma. Populations of the genus Pila colonised lacustrine habitats after this event, the derived form also showing striking thalassoid characters. There is no doubt that the intense morphological change occurred during a brief period, geologically speaking. The degree of morphological change in molluscs appears hence not to be linked with time. After the sudden radiation all lineages remain morphologically stable until they became extinct c. 1 Ma later. This pattern corresponds to the punctuated equilibrium model. Other groups (viviparids, thiarids) show more gradual changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019372
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    Effects of L-alanine and L-alanine peptides on the chemotaxis of tetrahymena: Evolutionary conclusions (1995)
    Springer
    Bioscience reports 15 (1995), S. 185-190 
    Details
    ISSN: 1573-4935
    Keywords: L-alanine ; evolution ; chemosensory response ; peptides ; imprinting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract L-alanine and its peptides (L-Ala-2–6) do not attract or repulse Tetrahymena in a 10−8M concentration. In 10−10M concentration there is a consistent repellent effect. Twenty four hours after L-alanine or L-alanine-peptides' pretreatment (imprinting) the progeny generation of the cells react differently to the same materials. L-Alanine, L-alanine penta- and hexapeptide in both concentrations are chemoattractant, while L-alanine tetrapeptide is repellent. L-Alanine dipeptide is inert in 10−10M and repellent at 10−8M concentrations, while L-alanine tripeptide is strongly repellent at 10−10M and attractant at 10−8M concentrations. This means, that the first encounter (imprinting) with an exogeneous amino acid or peptide is decisive to the later reaction of the protozoan cell. The chain length is important in the imprinting, however the reaction is not consistent. The experiments call the attention to the significance of imprinting in the receptor and hormone evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01540452
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  • 79
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    Demography of source—sink populations and the evolution of ecological niches (1995)
    Springer
    Evolutionary ecology 9 (1995), S. 38-44 
    Details
    ISSN: 1573-8477
    Keywords: demography ; dispersal ; ecological niche ; evolution ; heterogeneous environments ; natural selection ; source—sink populations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The demography of populations living in variable environments is an important factor molding the evolution of ecological niches, for it determines the relative strength of selection pressures on adaptations to different habitats. Here I consider a coarse-grained environment consisting of two habitat types and investigate how the selection pressure on reproductive success in different habitats depends on their quality and frequency and the dispersal pattern. The results suggest that selection on adaptations to optimal habitats will usually be stronger than on adaptations to poor habitats and the ecological niche will thus tend to be an evolutionarily conservative character. It is because under the habitat choice or limited dispersal that seem to prevail in natural populations, more individuals encounter the better habitat than would be expected solely on the basis of its relative area. This bias results in reduced selection pressure on reproductive success in the poorer habitat. With habitat choice or limited dispersal, selection pressure on reproductive success in the poorer habitat may exceed that on reproductive success in the better habitat only if the poorer habitat is much more frequent in the environment than the better habitat and the difference in their quality is not large.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01237695
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  • 80
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    Seasonal changes in spermatogenic cell degeneration in the seminiferous epithelium of adult Japanese macaques (Macaca fuscata fuscata) (1995)
    Springer
    Primates 36 (1995), S. 411-422 
    Details
    ISSN: 0032-8332
    Keywords: Apoptosis ; Degeneration of spermatogenic cells ; Japanese macaques ; Macaca fuscata fuscata ; Seminiferous epithelium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The degenerating pattern of spermatogenic cells in the seminiferous tubule of Japanese macaques was studied to clarify a relationship between seasonal changes of reproductive performances and cytological findings in the Japanese macaque. For light microscopy, testis samples were obtained from five adult animals by biopsy in April (nonmating season) and October (mating season). For electron microscopy, specimens from four additional macaques were used. Degenerating cells were found in all steps of spermatogenesis. In stages I to V of the cycle of the seminiferous epithelium, morphologically atypical pachytene spermatocytes were observed in 14.7 and 10.0% of the cells in the nonmating and mating seasons, respectively, although the difference in percentage was not significant. Mature spermatids with atypical features in those stages occupied 59.6% of the cells in the nonmating season, which significantly decreased to 34.1% in the mating season. These results imply that the seasonal change of sperm production is related, at least in part, to the process of degeneration of the spermatogenic cells in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382863
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    Alternative photophosphorylation, inorganic pyrophosphate synthase and inorganic pyrophosphate (1995)
    Springer
    Photosynthesis research 46 (1995), S. 87-91 
    Details
    ISSN: 1573-5079
    Keywords: bioenergetics ; photosynthesis ; chromatophores ; energy coupling ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This minireview in memory of Daniel I. Arnon, pioneer in photosynthesis research, concerns properties of the first and still only known alternative photophosphorylation system, with respect to the primary phosphorylated end product formed. The alternative to adenosine triphosphate (ATP), inorganic pyrophosphate (PPi), was produced in light, in chromatophores from the photosynthetic bacterium Rhodospirillum rubrum, when no adenosine diphosphate (ADP) had been added to the reaction mixture (Baltscheffsky H et al. (1966) Science 153: 1120–1122). This production of PPi and its capability to drive energy requiring reactions depend on the activity of a membrane bound inorganic pyrophosphatase (PPase) (Baltscheffsky M et al. (1966) Brookhaven Symposia in Biology, No. 19, pp 246–253); (Baltscheffsky M (1967) Nature 216: 241–243), which pumps protons (Moyle J et al. (1972) FEBS Lett 23: 233–236). Both enzyme and substrate in the PPase (PPi synthase) are much less complex than in the case of the corresponding adenosine triphosphatase (ATPase, ATP synthase). Whereas an artificially induced proton gradient alone can drive the synthesis of PPi, both a proton gradient and a membrane potential are required for obtaining ATP. The photobacterial, integrally membrane bound PPi synthase shows immunological cross reaction with membrane bound PPases from plant vacuoles (Nore BF et al. (1991) Biochem Biophys Res Commun 181: 962–967). With antibodies against the purified PPi synthase clones of its gene have been obtained and are currently being sequenced. Further structural information about the PPi synthase may serve to elucidate also fundamental mechanisms of electron transport coupled phosphorylation. The existence of the PPi synthase is in line with the assumption that PPi may have preceded ATP as energy carrier between energy yielding and energy requiring reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020419
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    Variation and phylogeny of the triploid cultivated potatoSolanum chaucha Juz. et Buk. based on RAPD and isozyme markers (1995)
    Springer
    Genetic resources and crop evolution 42 (1995), S. 373-386 
    Details
    ISSN: 1573-5109
    Keywords: evolution ; genetic distance ; isozymes ; RAM ; Solanum chaucha ; varietal classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ninety four accessions of the cultivated triploid potatoS. chaucha were analyzed and classified in genotypic groups using 9 isozyme loci and RAPD markers disclosed by 20 arbitrary 10-mer primers. Eight isozyme loci out of nine were polymorphic. A total of 22 allozymes were analyzed but none of them were specific for any genotypic group. About half (52%) of the 102 RAPD markers scored, were polymorphic, all of them showing polymorphism among groups and rarely within groups. Eighteen RAPD markers were specific for certain genotypes. The isozyme markers showed a certain amount of intra group variation which made classification less reliable than with RAPD markers. A total of 10 triploid genetic groups were discriminated using both techniques together. A single primer was found to be sufficient to distinguish all 10 groups. All varieties of a single group are considered to have been derived from the same cross and then clonally propagated, even though there is a high amount of morphological variation within a single genotypic group due probably to somatic mutations. RAPD markers have been shown to be more reliable in the classification of triploid potato varieties than other genetic markers like isozymes, proteins and morphological traits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02432142
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  • 83
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    Sequence evolution of theGpdh gene in theDrosophila virilis species group (1995)
    Springer
    Genetica 96 (1995), S. 293-302 
    Details
    ISSN: 1573-6857
    Keywords: D. virilis phylad ; evolution ; Gpdh gene ; nucleotide sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nucleotide sequence of theGpdh gene from six taxa,D. virilis, D. lummei, D. novamexicana, D. a. americana, D. a. texana andD. ezoana, belonging to thevirilis species group was determined to examine details of evolutionary change in the structure of theGpdh gene. TheGpdh gene is comprised of one 5′ non-translated region, eight exons, seven introns and three 3′ non-translated regions. Exon/intron organization was identical in all the species examined, but different from that of mammals. Interspecific nucleotide divergence in the entireGpdh gene followed the common pattern: it was low in the exon, high in the intron and intermediate in the non-translated regions. The degree of nucleotide divergence differed within these regions, suggesting that selection exerts constraints differentially on nucleotide change of theGpdh gene. A phylogenetic tree of thevirilis phylad constructed from nucleotide variation of total sequence was consistent with those obtained from other data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01439583
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    Dormancy in the Copepoda — an overview (1995)
    Springer
    Hydrobiologia 306 (1995), S. 199-211 
    Details
    ISSN: 1573-5117
    Keywords: Diapause ; ecology ; evolution ; life history ; marine ; freshwater ; Copepoda
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dormancy affects copepods in their anatomy, physiology, genetics, population biology, community ecology, evolution and local and geographic distribution. It is known from freeliving representatives of three copepod taxa, namely the Harpacticoida, Cyclopoida and Calanoida. Species showing dormancy occur in various realms and habitats, both freshwater and marine, being benthic, planktic or ice-dwelling. Depending on the taxon, dormancy occurs at various times of the year, prevailing in higher and temperate latitudes. Copepod dormancy is expressed in various ontogenetic stages, such as resting eggs, arrested larval development, juvenile and adult encystment, or arrested development of nonencysted copepodids or adults. Ecologically, dormancy is an energy saving trait, allowing the individual to bridge periods of environmental harshness. Adverse environmental conditions could be abiotic (e.g. desiccation, temperature, oxygen availability) or biotic in nature (e.g. food availability, predation). Diapause s. str. is initiated, maintained and terminated by triggering factors (e.g. photoperiod, temperature, chemical cues, population density/physiological factors). The dormant state and emergence patterns directly affect reproduction, population dynamics, community composition, coexistence and distribution of copepods, as well as the phenology of their predators and living food items. Populations having dormancy, in most cases belong to and affect communities of two realms: the water column and the bottom. Dormant stages may provide means for dispersal as well as for staying in special localities. The variability of dormancy permits flexible and complex life histories. Dormancy is subjected to and on the other hand affects copepod evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00017691
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    Molecular evolution in bacteria (1995)
    Springer
    Antonie van Leeuwenhoek 67 (1995), S. 315-324 
    Details
    ISSN: 1572-9699
    Keywords: bacteria ; ecology ; evolution ; metabolism ; microbiology ; molecular biology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent advances in microbiology and molecular biology have a unifying influence on our understanding of genetic diversity/similarity and evolutionary relationships in microorganisms. This article attempts to unify information from diverse areas such as microbiology, molecular biology, microbial physiology, clay crystal genes, metals-microbe-clay interactions and bacterial DNA restriction-modification systems (R-M) as they may apply to molecular evolution of bacteria. The possibility is discussed that the first informational molecules may have been catalytic RNA (micro-assembler) not DNA (now the master copy) and these first micro-assemblers may have been precursors of ribosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00872929
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    Phylogenesis of fission yeasts. Contradictions surrounding the origin of a century old genus (1995)
    Springer
    Antonie van Leeuwenhoek 68 (1995), S. 119-149 
    Details
    ISSN: 1572-9699
    Keywords: Schizosaccharomyces ; sequence comparison ; evolution ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phylogenesis of fungi is controversial due to their simple morphology and poor fossilization. Traditional classification supported by morphological studies and physiological traits placed the fission yeasts in one group with ascomycetous yeasts. The rRNA sequence comparisions, however, revealed an enormous evolutionary gap betweenSaccharomyces andSchizosaccharomyces. As shown in this review, the protein sequences also show a large gap which is almost as large as that separatingSchizosaccharomyces from higher animals. Since the two yeasts share features (both cytological and molecular) in common which are also characteristic of ascomycetous fungi, their separation must have taken place later than the sequence differences may suggest. Possible reasons for the paradox are discussed. The sequence data also suggest a slower evolutionary rate in theSchizosaccharomyces lineage than in theSaccharomyces branch. In the fission yeast lineage two ramifications can be supposed. FirstS. japonicus (Hasegawaea japonica) branched off, thenS. octosporus (Octosporomyces octosporus) separated fromS. pombe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00873099
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    Qualitative mathematical discussion of different evolutionary states in water transport systems of plants (1995)
    Springer
    Journal of biological physics 21 (1995), S. 241-264 
    Details
    ISSN: 1573-0689
    Keywords: Synergetics ; dynamical systems ; water transport ; evolution ; stele
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract We shall present several qualitative mathematical models to describe the early evolution of water transport systems in plants. To perform this in a systematic way we apply methods which have been developed in phenomenological synergetics. These methods rest on the fact that it becomes possible to describe the macroscopic behavior of a complex system by a set of control and order parameters when they are suitably identified. Our presentation is addressed to community with interdisciplinary interests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00700627
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    The importance of chemical data for the study of interstellar shocks (1995)
    Springer
    Astrophysics and space science 233 (1995), S. 125-137 
    Details
    ISSN: 1572-946X
    Keywords: Interstellar Medium ; Dark Clouds ; Chemistry ; Bistability ; C-shock Waves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Shock waves perturb the chemical state of the interstellar gas. We consider the effects of C-shocks on the composition of molecular clouds, for a range of values of the pre-shock gas density and magnetic induction. The time required to re-establish equilibrium in the post-shock gas depends on the initial conditions and can become very large. The significance of the two known chemical phases of dark clouds and of bistability is considered in this context.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627340
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    Molecular diagnostics of diffusive boundary layers (1995)
    Springer
    Astrophysics and space science 233 (1995), S. 161-164 
    Details
    ISSN: 1572-946X
    Keywords: Stars ; Chemistry ; Diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have assessed the role of diffusion in determining chemical abundances in molecular interface regions. Chemical models have been developed which include the appropriate diffusion terms and that are appropriate to a narrow diffusion region (∼0.01pc) that may exist at the interface between a dark core and a hot, shocked T-Tauri wind. We have assumed pressure balance throughout and have calculated the chemical abundances as functions of time and position through the interface. The results show that significant enhancements of detectable molecules/transitions are expected (e.g. CO J=6→5, OH and CH). Using a realistic value of the diffusion coefficient a diffusive region of dimension 0.01pc may be established within about 104 years. In general it seems likely that diffusion processes are highly significant on these and smaller lengthscales.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627344
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  • 90
    Electronic Resource
    Electronic Resource
    Molecular evolution of influenza viruses (1995)
    Springer
    Virus genes 11 (1995), S. 209-215 
    Details
    ISSN: 1572-994X
    Keywords: influenza virus ; evolution ; phylogeny ; species barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There are two different mechanisms by which influenza viruses might evolve: (1) Because the RNA genome of influenza viruses is segmented, new strains can suddenly be produced by reassortment, as happens, for example, during antigenic shift, creating new pandemic strains. (2) New viruses evolve relatively slowly by stepwise mutation and selection, for example, during antigenic or genetic drift. Influenza A viruses were found in various vertebrate species, where they form reservoirs that do not easily mix. While human influenza A viruses do not spread in birds and vice versa, the species barrier to pigs is relatively low, so that pigs might function as “mixing vessels” for the creation of new pandemic reassortants in Southeast Asia, where the probability is greatest for double infection of pigs by human and avian influenza viruses. Phylogenetic studies revealed that about 100 years ago, an avian influenza A virus had crossed the species barrier, presumably first to pigs, and from there to humans, forming the new stable human and classical swine lineages. In 1979, again, an avian virus showed up in the North European swine population, forming another stable swine lineage. The North European swine isolates from 1979 until about 1985 were genetically extremely unstable. A hypothesis is put forward stating that a mutator mutation is necessary to enable influenza virus to cross the species barrier by providing the new host with sufficient variants from which it can select the best fitting ones. As long as the mutator mutation is still present, such a virus should be able to cross the species barrier a second time, as happened about 100 years ago. Although the most recent swine isolates from northern Germany are again genetically stable, we nevertheless should be on the lookout to see if a North European swine virus shows up in the human population in the near future.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728660
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  • 91
    Electronic Resource
    Electronic Resource
    The evolution of small DNA viruses of eukaryotes: Past and present considerations (1995)
    Springer
    Virus genes 11 (1995), S. 239-257 
    Details
    ISSN: 1572-994X
    Keywords: small DNA viruses ; polyomavirus ; papillomavirus ; parvovirus ; polydnavirus ; evolution ; co-evolution ; co-speciation ; immune system ; cytokines ; acute phase reaction ; persistence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Historically, viral evolution has often been considered from the perspective of the ability of the virus to maintain viral pathogenic fitness by causing disease. A predator-prey model has been successfully applied to explain genetically variablequasi-species of viruses, such as influenza virus and human immunodeficiency virus (HIV), which evolve much faster rates than the host. In contrast, small DNA viruses (polyomaviruses, papillomaviruses, and parvoviruses) are species specific but are stable genetically, and appear to have co-evolved with their host species. Genetic stability is attributable primarily to the ability to establish and maintain a benign persistent state in vivo and not to the host DNA proofreading mechanisms. The persistent state often involves a cell cycle-regulated episomal state and a tight linkage of DNA amplification mechanisms to cellular differentiation. This linkage requires conserved features among viral regulatory proteins, with characteristic host-interactive domains needed to recruit and utilize host machinery, thus imposing mechanistic constrains on possible evolutionary options. Sequence similarities within these domains are seen amongst all small mammalian DNA viruses and most of the parvo-like viruses, including those that span the entire spectrum of evolution of organisms fromE. coli to humans that replicate via a rolling circle-like mechanism among the entire spectrum of organisms throughout evolution fromE. coli to humans. To achieve benign inapparent viral persistence, small DNA viruses are proposed to circumvent the host acute phase reaction (characterized by minimal inflammation) by mechanisms that are evolutionarily adapted to the immune system and the related cytokine communication networks. A striking example of this is the relationship of hymenoptera to polydnaviruses, in which the virus is crucial to the recognition of self, development, and maintenance of genetic identity of both the host and virus. These observations in aggregate suggest that viral replicons are not recent “escapies” of host replication, but rather provide relentless pressure in driving the evolution of the host through cospeciation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728663
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  • 92
    Electronic Resource
    Electronic Resource
    Retrotransposition and herpesvirus evolution (1995)
    Springer
    Virus genes 11 (1995), S. 259-270 
    Details
    ISSN: 1572-994X
    Keywords: herpesviruses ; evolution ; retrovirus integration ; retrotransposition ; gene capture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract One of the more interesting developments in herpesvirus evolution concerns the acquisition of novel, non-ubiquitous herpesvirus genes. A number of these are related to known cellular genes. How did herpesviruses acquire such genes? Our recent demonstration of retrovirus integration into herpesviruses suggests a potentially important role for retrotransposition in herpesvirus evolution and in the acquisition of novel genes, cellular in origin. Herpesvirus genome development has been characterized by a number of structural and evolutionary properties that support this proposal. We first discuss the evidence for retroviral integration into herpesviruses. The functional significance of this phenomenon is presently unclear. However, in the broader context of retrotransposition, a number of attractive features serve to explain the capture of structural and regulatory elements throughout herpesvirus evolution. These possibilities are discussed in detail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728664
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  • 93
    Electronic Resource
    Electronic Resource
    Structure, function, and evolution of bacterial reverse transcriptase (1995)
    Springer
    Virus genes 11 (1995), S. 81-94 
    Details
    ISSN: 1572-994X
    Keywords: retrons ; reverse transcriptase ; prokaryotes ; msDNA ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The discovery of retroelements in the prokaryotes raises intriguing questions concerning their roles in bacteria and the origin and evolution of reverse transcriptases. We first discuss a possible structure of bacterial reverse transcriptases on the basis of the known three-dimensional structure of HIV-1 reverse transcriptase, and how such a putative three-dimensional structure is able to recognize a single primer-template RNA molecule to initiate DNA chain elongation from the 2′-OH group of an internal G residue. This reaction leads to the production of a unique RNA-DNA complex calledmsDNA (multicopy single-stranded DNA) in which a single-stranded DNA branches out from an RNA molecule via a 2′,5′-phosphodiester linkage. Second, the mobility of the bacterial retroelements calledretrons, responsible for the production of msDNA, are discussed and compared with the mobility of group I and group II introns. Third, the original and evolution of bacterial reverse transcriptases are discussed in light of the question of whether the bacterial reverse transcriptases are older than eukaryotic reverse transcriptases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728650
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  • 94
    Electronic Resource
    Electronic Resource
    Evolution of T4-related phages (1995)
    Springer
    Virus genes 11 (1995), S. 285-297 
    Details
    ISSN: 1572-994X
    Keywords: T-even phage ; T4 phage ; evolution ; DNA duplication ; horizontal gene transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Much progress has been made in understanding T-even phage biology in the last 50 years. We now know the entire sequence of T4, encoding nearly 300 genes, only 69 of which have been shown to be essential under standard laboratory conditions; no specific function is yet known for about 140 of them. The origin of most phage genes is unclear, and only 42 genes in T4 have significant similarity to anything currently included in GenBank. Comparative analysis of related phages is now being used to gain insight into both the evolutionary origins and interrelationships of these phage genes, and the functions of their protein products. The genomes of phages isolated from Tbilisi hospitals, Long Island sewage plants, the Denver zoo, and Khabarovsk show basic similarity. However, these phages show substantial insertions and deletions in a number of regions relative to each other, and closer investigation of specific sequences often reveals much more complex relationships. There are only a few cases in T4-related phages in which there is evidence for evolution through DNA duplication. These include the fibrous products of genes 12, 34, and 37; head proteins gp23 and gp24; and the Alt enzyme and its downstream neighbors. T4 also contains 13 apparent relatives of group I and group II intron homing endonucleases. Distal portions of the tail fibers of various T-even phages contain segments closely related to tail-fiber regions of other DNA coliphages, such as Mu, P1, P2, and lambda. Horizontal gene transfer clearly emerges as a major factor in the evolution of at least the tail-fiber regions, where site-specific recombination probably is involved in the exchange of host-range determinants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728666
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  • 95
    Electronic Resource
    Electronic Resource
    Variation and phylogeny of the ribosomal DNA unit types and 5 S DNA inPetunia Jussieu (1995)
    Springer
    Genetic resources and crop evolution 42 (1995), S. 311-325 
    Details
    ISSN: 1573-5109
    Keywords: evolution ; 5 S DNA ; Petunia ; ribosomal DNA RFLP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seven wildPetunia species including 2n = 18 species (P. parviflora Jussieu,P. linearis Hook.) and those with 2n = 14 (P. parodii Steene,P. axillaris Lam.,P. integrifolia Hook.,P. inflata R.E. Fries,P. violacea Lindl.) and tenPetunia hybrida horticultural lines were compared for polymorphisms in rDNA genes using the four restriction enzymesEcoRI,BamHI,HindIII andXhoI. All the unit types found in the lines pre-existed in the wild forms. There are two different sizes of either 11.45 or 11.6 kb./The 2n = 18 species are closely related to the 2n = 14 species, thus making thePetunia genus homogeneous. Moreover, it is likely thatP. hybrida lines originated in several kinds of crosses between these species. We constructed a dendrogram for all the 15 rDNA unit types found. Two main branches of the tree result from the presence or the absence ofHindIII sites. The main branch is divided according to variability at theEcoRI andBamHI sites. Taking into account the existence of several loci which carry one unit type only, we consider whether or not exchanges might occur between loci. Lines carrying two unit types and lines carrying three unit types support such a hypothesis.XhoI andBamHI fragments enable us to distinguish two types of 5S DNA corresponding to 2n = 18 and 2n = 14 species, respectively.P. hybrida lines and each 2n = 14 wild species carry one of the types only, that corresponds to one 5S DNA locus. The most parsimonious phylogenetic trees whatever the species chosen as the outgroup, do not fit with our knowledge ofPetunia and with taxonomy. This is likely because only few loci formed the basis of these phylogenetic constructions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02432135
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  • 96
    Electronic Resource
    Electronic Resource
    Discovery of 2n gametes in tetraploid oat Avena vaviloviana (1995)
    Springer
    Euphytica 81 (1995), S. 1-6 
    Details
    ISSN: 1573-5060
    Keywords: Avena ; 2n gametes ; binucleate cell ; evolution ; sexual polyploidization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Sexual polyploidization via the action of 2n gametes (gametes with the sporophytic chromosome number) has been identified as the most important evolutionary mode of polyploidization among plant genera. This study was conducted to determine whether 2n gametes are present in the tetraploid level of the genus Avena (2n=4×=28) Twenty tetraploid Avena lines, representing four species and one interspecific hybrid, were screened for pollen grain size in order to differentiate between n and 2n pollen. Avena vaviloviana (Malz.) Mordv. line PI 412767 was observed to contain large pollen grains at a 1.0% frequency. Cytogenetic analyses of pollen mother cells of PI 412767 revealed cells with double the normal chromosome number (i.e., 56 chromosomes at metaphase I and anaphase I). The mode of chromosome doubling was found to be failure of cell wall formation during the last mitotic division that preceded meiosis. The resulting binucleate cells underwent normal meiotic divisions and formed pollen grains with 28 chromosomes. Based on the formation and function of 2n gametes, three models involving diploid and tetraploid oat lines are proposed to describe possible evolutionary pathways for hexaploid oats. If stable synthetic hexaploid oat lines could be developed by utilizing 2n gametes from diploid and tetraploid oat species through bilateral sexual polyploidization, the resulting hexaploids could be used in breeding programs for transferring genes from diploids and tetraploids to cultivated hexaploids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00022452
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  • 97
    Electronic Resource
    Electronic Resource
    Evolutionary aspects of gonadotropin-releasing hormone and its receptor (1995)
    Springer
    Cellular and molecular neurobiology 15 (1995), S. 5-23 
    Details
    ISSN: 1573-6830
    Keywords: evolution ; reproduction ; gonadotropin-releasing hormone (GnRH) structure ; GnRH function ; GnRH receptor structure ; GnRH receptor function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Gonadotropin-releasing hormone (GnRH) was originally isolated as a hypothalamic peptide hormone that regulates the reproductive system by stimulating the release of gonadotropins from the anterior pituitary. However, during evolution the peptide was subject to gene duplication and structural changes, and multiple molecular forms have evolved. 2. Eight variants of GnRH are known, and at least two different forms are expressed in species from all vertebrate classes: chicken GnRH II and a second, unique, GnRH isoform. 3. The peptide has been recruited during evolution for diverse regulatory functions: as a neurotransmitter in the central and sympathetic nervous systems, as a paracrine regulator in the gonads and placenta, and as an autocrine regulator in tumor cells. 4. Evidence suggests that in most species the early-evolved and highly conserved chicken GnRH II has a neurotransmitter function, while the second form, which varies across classes, has a physiologic role in regulating gonadotropin release. 5. We review here evolutionary aspects of the family of GnRH peptides and their receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02069556
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  • 98
    Electronic Resource
    Electronic Resource
    Evolutionary perspectives on sexual offending (1995)
    Springer
    Sexual abuse 7 (1995), S. 301-315 
    Details
    ISSN: 1573-286X
    Keywords: evolution ; gender differences ; incest ; sexual aggression ; sexual offending
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract Evolutionary psychology has been successful in explaining diverse phenomena, such as the relative rarity with which people commit crimes against their biological relatives and the observed differences between males and females in romantic and sexual interest. According to an evolutionary view, the current sexual motivations of males and females were created in ancestral environments through their relationship with reproductive success. Sexual offending may arise in the context of a male sexual psychology that has been designed to maximize reproductive success by varying the proportion of mating effort and parental investment expended according to circumstances. Various kinds of sexual offending appear to be particular manifestations of this male sexual psychology either as modified by the offender's ontogenetic history or as pathology caused by some aspect of the normal sexual preference mechanism gone awry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02256834
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  • 99
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    Electronic Resource
    Optimization of mechanical strength of reinforced composites. 1. Study on the effect of reactive bismaleimide on the mechanical performance of CaCo3-filled polypropylene (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 224 (1995), S. 9-20 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß von 3-Phenylenbismaleimid auf die Werkstoffeigenschaften von CaCO3 gefüllten Polypropylen-Verbundstoffen wurde untersucht. Die Verarbeitungstemperatur spielte eine entscheidende Rolle bei der Herstellung der Verbundwerkstoffe. Bei Verarbeitungstemperaturen oberhalb der Bismaleimid-Zersetzungstemperatur zeigte die Bismaleimid-Verbindung einen positiven Effekt. Die chemische Zusammensetzung der modifizierten Verbunde wurde mit den mechanischen Eigenschaften korreliert. Basierend auf ESCA-Analysen werden Wechselwirkungen zwischen dem Polymeren und CaCO, diskutiert.
    Notes: The effect of 3-phenylene bismaleimide on the mechanical performance of an inorganic filler-based polypropylene composite was studied. The selection of processing temperature played a significant role in the preparation of such composites. A positive effect of the bismaleimide compound was obtained for a processing temperature above the decomposition temperature of bismaleimide. The chemical composition of the modified composite was correlated to its mechanical strength by experimentation involving a rotatable design. An interaction between polymer and CaCO3 has been proposed based on ESCA analysis.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052240102
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  • 100
    Electronic Resource
    Electronic Resource
    The effect of the processing steps on the oxidative stability of polyethylene tubing crosslinked by irradiation (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 224 (1995), S. 33-48 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Chemische und mechanische Eigenschaften von Zwischenprodukten der PE-Schrumpfschlauch-Produktion wurden bei unterschiedlichen Compound-Zusammensetzungen (PE, ein aromatisches Amin oder Phenolderivat als Antioxidans und in einigen Fällen ein Flammschutzmittel und/oder eine Elastomerkomponente) untersucht.Während der Herstellung, besonders während der durch Elektronenstrahlung initiierten Vernetzung, nimmt die thermooxidative Stabilität des Materials gegenüber der des compoundierten Granulats ab. Das aromatische Amin scheint bei gleicher Zusammensetzung das wirksamere und strahlungsbeständigere Antioxidans im Vergleich zum Phenolderivat zu sein. Die Oxidationsstabilität der hergestellten Schrumpfschläuche wird nicht von der Qualität des eingesetzten PE-Ausgangsgranulats beeinflußt.Durch die Alterung des Materials ändern sich die mechanischen Eigenschaften geringfügig. Die Elastomerzugabe bewirkt keine Änderung von Zugfestigkeit und Reißdehnung. Die Stabilität des Endprodukts ist bei weitem ausreichend, um den Spannungen, die beim Schrumpfen während des Gebrauchs auftreten, standzuhalten. Die gute Zugfestigkeit des Materials wird durch die Alterung ebenfalls nicht beeinträchtigt.Bei der Extrusion des Granulats tritt keine nennenswerte Änderung des Molekulargewichts bzw. der Molekulargewichtsverteilung auf. Durch die Bestrahlung wird das Material vernetzt und zu mehr als 50% unlöslich, und seine thermooxidativen Eigenschaften ändern sich deutlich gegenüber dem ursprünglichen PE und dem daraus compoundierten Material.
    Notes: Some chemical and mechanical properties of intermediate products obtained in the production of PE heat-shrinkable tubes were studied at different compositions of the material containing PE, antioxidant (aromatic amime or phenol) and, in some cases, flame retardant and/or an elastomer.In the course of the production phase, the thermooxidative stability decreases compared to that of compounded granulate. The greatest decrease is caused by irradiation. The aromatic amine seems to be a more effective antioxidant at similar compositions than the phenol derivative, and it shows a better resistance against irradiation. The oxidative stability of the finished shrinkable tubes is not affected by the quality of commercial granulate (initial polyethylene).Mechanical properties change slightly upon ageing, and the introduction of the elastomer did not alter the tensile strength and elongation at break. The remaining stability of the end product was still high enough to bear the stress of shrinking in use, and the good tensile strength of the material did not decrease upon thermal ageing either.In the extrusion of the granulated compound no significant change in the distribution and average molecular weight took place. Irradiation produced more than 50% insoluble fraction and the thermooxidative properties of the crosslinked sample changed significantly compared to the original PE and to the compound prepared from it.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052240104
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