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  • 1985-1989  (1,319)
  • 1975-1979  (311)
  • 1988  (750)
  • 1985  (569)
  • 1979  (311)
  • Biochemistry and Biotechnology  (1,336)
  • Ultrastructure  (294)
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  • 1985-1989  (1,319)
  • 1975-1979  (311)
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Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructural characterisation of macrophages (type A cells) in the synovial lining (1988)
    Springer
    Rheumatology international 8 (1988), S. 171-176 
    Details
    ISSN: 1437-160X
    Keywords: Ultrastructure ; Synovium ; Macrophages ; Immunoelectron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural localisation of class II and macrophage antigens has been sought in the intimal layer of the human synovium. The cells described as type A in early morphological studies are shown to express both class II antigens and two markers of the macrophage/monocyte lineage of cells, OKM1 and MAB 24. The morphological type B cells were found to express none of these antigens. The findings are consistent with the idea that the synovial lining comprises two cell types, bone-marrow derived macrophages and mesenchymal fibroblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270456
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  • 2
    Electronic Resource
    Electronic Resource
    Collagenous colitis: Histologic, morphometric, immunohistochemical and ultrastructural studies. Report of 21 cases (1988)
    Springer
    Virchows Archiv 413 (1988), S. 287-296 
    Details
    ISSN: 1432-2307
    Keywords: Collagenous colitis ; Myofibroblasts ; Myoid cells ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined 129 colonic biopsies from 21 patients with collagenous colitis, most of whom presented with diarrhoea. Morphometric measurements gave a mean thickness of the subepithelial collagen deposit of 19.5 µ ± 5.1. The trapped fusiform and/or stellate cells within the deposits were identified immunohistochemically as myoid cells, being positive with antibody against smooth muscle cell alpha-actin. Ultrastructurally, these cells have all the characteristic features of myofibroblasts. Similar cells are also present along the crypts, where they were formerly referred to as pericryptal fibroblasts. Although there is still much debate as to the pathogenesis of this condition, we would like to suggest that collagenous colitis is a disease of pericryptal myofibroblasts. During their migration and maturation into the subepithelial region they may synthesize an excess of collagen, under some yet unknown or undefined stimulus/stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00783020
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural and immunohistochemical characteristics of lipid-rich carcinoma of the breast (1988)
    Springer
    Virchows Archiv 413 (1988), S. 381-385 
    Details
    ISSN: 1432-2307
    Keywords: Lipid rich carcinoma ; Breast ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five cases of lipid-rich carcinomas of the breast were investigated ultrastructurally and immunohistochemically for alpha-lactalbumin (ALA), lactoferrin (Lfr) and human milk fat globule membrane antigen (HMFG-2). Staining for ALA and Lfr showed intensive reaction on nearly all of the tumour cells whereas immunoreaction for HMFG-2 revealed positivity in single cells. All tumours were negative for steroid receptor content. Ultrastructurally the tumour cells showed numerous intracytoplasmic non-membrane bound lipid droplets which were often found within autophagocytic vacuoles. Neither rough endoplasmic reticulum nor Golgi complexes showed any sign of lipid synthesis. Extrusion of lipid droplets and extracellular lipid deposition was not observed. In conclusion, our findings do not justify the consideration of lipid-rich carcinoma of the breast as a clearly defined group of tumours with specific secretory activity. Therefore, the term lipid-rich carcinoma should be used in preference to lipid-secreting, unless there is evidence of active lipid secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00716986
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  • 4
    Electronic Resource
    Electronic Resource
    Cat scratch disease (1988)
    Springer
    Virchows Archiv 412 (1988), S. 563-572 
    Details
    ISSN: 1432-2307
    Keywords: Cat scratch disease ; Epidemiology ; Ultrastructure ; Bacterial morphology ; Warthin-Starry stain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aetiological agent of cat scratch disease (CSD) has been unknown for more than 30 years. Recently, a micro-organism clearly shown with Warthin-Starry silver (W-S) stain was found and thought to be a possible cause of the disease. In this study, 32 cases of regional lymphadenopathy histologically compatible with CSD and 20 contrasting cases of lymphadenopathy were examined retrospectively with W-S stain. W-S positive pleomorphic organisms were clearly demonstrated in 20 of the 32 suspected cases of CSD, but in none of the other cases. The onset of disease in these 20 cases with W-S positive organisms occurred between July and January. This seasonal variation in the onset of disease was highly significant (P〈0.005) and was not due to a single epidemic. Moreover, some characteristic morphological features of the organism were found by electron microscopic observations. Ultrastructurally, the organism was a bacterium showing a chain-like arrangement, septal formation, branching and clubbed ends.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00844292
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of intralipid and hydrocortisone upon human fetal lung cell cultures (1988)
    Springer
    Research in experimental medicine 188 (1988), S. 411-423 
    Details
    ISSN: 1433-8580
    Keywords: Human fetal lung cell cultures ; Lamellar bodies ; Pneumocytes type II ; Intralipid ; Hydrocortisone ; Ultrastructure ; Morphometric analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Organotypic cell culture systems of human fetal lungs of 15, 18, and 26 weeks' gestational age were treated with Intralipid, a phosphatidylcholine-containing lipid mixture, and with hydrocortisone of varying concentrations. The lamellar bodies found in the pneumocytes type II were ultrastructurally identified. Their amount was quantitated by point-counting, a morphometrical method. Intralipid had a stimulating effect upon the surfactant production depending on the concentration admitted. This effect was quantitatively compared to the known effect of hydrocortisone. Intralipid at a concentration of 10−2% produced a significant increase of the relative volume of lamellar bodies (P = 0.05) at a gestational age of 18 weeks. This effect is comparable to hydrocortisone treatment at a concentration of 10−1% (P = 0.05) and 10−3% (P = 0.01). At a gestational age of 26 weeks, Intralipid at a concentration of 10−1% (P = 0.01) stimulated lamellar body production. Hydrocortisone had a similar effect at a concentration of 10−1% (P = 0.01). Intralipid does not pass the placenta-barrier and is locally applied by amniocentesis. Therefore, complications to the maternal organism and probably to the fetuses are negligible. The application of Intralipid represents an alternative method to accelerate antenatal surfactant production and to improve the rate of survival of preterm infants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01851999
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural identification of Merkel cells around the mouth of the newborn marsupial (1988)
    Springer
    Anatomy and embryology 177 (1988), S. 403-408 
    Details
    ISSN: 1432-0568
    Keywords: Marsupial ; Newborn ; Ultrastructure ; Merkel cells ; Mechanoreceptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the epidermal cells surrounding the mouth of three newborn marsupial species, the Northern native cat Dasyurus hallucatus, the brush tail possum Trichosurus vulpecula and the Northern brown bandicoot Isoodon macrourus were examined. The presence of Merkel cells, highly sensitive touch receptors, would suggest that the sense of touch aids the relatively underdeveloped newborn marsupial to move from the urinogenital sinus to the pouch and to locate the teat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304737
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  • 7
    Electronic Resource
    Electronic Resource
    Esthesioneuroblastoma: a nasal catecholamine-producing tumor of neural crest origin (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 522-527 
    Details
    ISSN: 1432-0533
    Keywords: Esthesioneuroblastoma ; Tyrosine hydroxylase (TH) ; Immunohistochemistry ; Ultrastructure ; Catecholamine-producing tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An esthesioneuroblastoma in a 16-year-old male was studied ultrastructurally and immunohistochemically, using antiserum against tyrosine hydroxylase (TH), a rate-limiting enzyme in the catecholamine-synthesizing pathway. Tumor cells were fairly uniform in appearance, showing scantly cosinophilic cytoplasm and round to oval hyperchromatic nuclei, and were arranged in nests and cords of various sizes. Ultrastructurally, individual tumor cells had well-developed cell organelles including polyribosomes, microtubules, intermediate filaments, centrioles, Golgi apparatus and mitochondria. Secretory-like granules were occasionally found, predominantly in the cell processes. Immunohistochemically, many tumor cells were shown to be immunoreactive for TH. This finding strongly suggested that the present tumor was capable of producing catecholamines and that it might be derived from certain sympathetic neuronal cell nests in the superior nasal cavity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686393
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  • 8
    Electronic Resource
    Electronic Resource
    Creutzfeldt-Jakob disease with intranuclear vacuolar inclusions: a biopsy case of negative light microscopic findings and successful animal transmission (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 422-426 
    Details
    ISSN: 1432-0533
    Keywords: Creutzfeldt-Jakob disease ; Slow virus ; Pathology ; Ultrastructure ; Intranuclear vacuolar inclusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a 53-year-old man with a progressive mental deterioration and myoclonic jerks, brain biopsy failed to show any significant light microscopical findings. Electron microscopy revealed membranebound vacuolar inclusions in many neuronal nuclei as the only prominent finding. Hamsters intracerebrally inoculated with the biopsy material demonstrated typical spongiform changes in the gray structures of the brain when sacrificed on the 309th and 332nd days post inoculation, characteristic of experimental Creutzfeldt-Jakob disease (CJD). These intranuclear vacuolar inclusions, originally reported in experimental Creutzfeldt-Jakob disease in this laboratory, may be a valuable electron microscopic feature in some CJD cases and may play an important role in supporting the diagnosis of CJD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686980
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  • 9
    Electronic Resource
    Electronic Resource
    Cytomembranous inclusions in the brain of a patient with the acquired immunodeficiency syndrome (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 101-106 
    Details
    ISSN: 1432-0533
    Keywords: AIDS ; Confronting cylindrical cisterns ; Cytomembranous inclusions ; Tubuloreticular inclusions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural studies of cells and tissues in the acquired immunodeficiency syndrome (AIDS) have revealed two distinct cytomembranous inclusions referred to as “tubuloreticular inclusions” (TRI) and “confronting cylindrical cisterns” (CCC). TRI are found most often in leukocytes and endothelial cells in conditions with elevated levels of alpha-interferon, such as viral infections, autoimmune diseases and certain neoplasms. On the other hand, CCC are detected almost exclusively in mononuclear inflammatory cells and are limited to a few conditions, of which AIDS is the most common. CCC have been proposed as an ultrastructural marker for human immunodeficiency virus (HIV) infection. We describe CCC in mononuclear inflammatory cells in the brain of a patient with AIDS. Finding CCC in brain tissue with no other specific feature such as multinucleated giant cells, nevertheless, should alert the neuropathologist to the possibility that the patient might have AIDS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687686
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  • 10
    Electronic Resource
    Electronic Resource
    Scanning electron microscopy of in vitro fertilization in cattle (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 41-46 
    Details
    ISSN: 1432-0568
    Keywords: In vitro fertilization ; Bovine ; Ultrastructure ; Ova ; Spermatozoa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes were collected from cows at an abattoir by aspiration from small (1–6 mm) follicles. The complexes were matured in vitro for 28 h. Subsequently, the cumulus cells and the zona pellucida were removed by enzyme treatment in a proportion of the complexes (zona-free ova). Both cumulus-enclosed and zonafree ova were inseminated in vitro and processed for scanning electron microscopy after different periods of culture. In the cumulus-enclosed ova the number of spermatozoa attached to and penetrating into the cumulus investment increased with increasing culture time. Practically all spermatozoa displayed intact acrosomes. In the zona-free ova clusters of spermatozoa attached to the ovum surface, and at 5 h a proportion of the spermatozoa had undergone the acrosome reaction, and their internalization into the ooplasma was initiated. The acrosome reaction was characterized by an increasing fenestration of the membrane coverings of the acrosomal region of the sperm head. During the sperm head internalization, where the ovum microvilli appeared to contact especially the equatorial segment and the postacrosomal region, the sperm head gradually disappeared from the ovum surface, and the microvilli at the site of internalization became more bulbous. Simultaneous abstriction of the second polar body was seen in some ova.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305012
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  • 11
    Electronic Resource
    Electronic Resource
    Ultrastructural abnormalities of in vitro fertilization of in vitro matured bovine oocytes (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 47-52 
    Details
    ISSN: 1432-0568
    Keywords: Ultrastructure ; In vitro fertilization ; Bovine ; Ova ; Cortical granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes collected from cows at an abattoir by aspiration from small (1–6 mm) antral follicles were matured and inseminated in vitro. At different time intervals after insemination the ova were processed for transmission electron microscopy. Up to and including 6 h after insemination all ova were unfertilized, and their cortical granules were more or less clustered. At 6 h acrosome reaction of spermatozoa was observed on the surface of the zona pellucida. At 8 h the first fertilized ovum appeared and the first fully developed spherical pronucleus was observed, at 20 h the first apposition of pronuclei was seen, and at 40 h divisions were ongoing or completed. More than one third of the fertilized ova showed polyspermic penetration of the zona pellucida, and in most of these ova different developmental stages of supernumerary pronucleus formation were observed in the ooplasm. Abnormal cortical granule release was seen in approximately half of the fertilized ova, and it was more frequent in ova with polyspermic as opposed to monospermic penetration of the zona pellucida.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305013
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  • 12
    Electronic Resource
    Electronic Resource
    Effects of oxygen concentration on embryonic development in rats: a light and electron microscopic study using whole-embryo culture techniques (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 337-343 
    Details
    ISSN: 1432-0568
    Keywords: Hyperoxia ; Hypoxia ; Teratogenesis ; Rat embryo ; Whole-embryo culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By using a whole-embryo culture technique (New 1978), the effects of oxygen concentration (5%, 20% and 95% oxygen) on embryonic development in the rat were investigated by light and electron microscopy. The best embryonic development occurred when the 9.5-day-old embryos were cultured for 24 h with 5% oxygen, and the 10.5-day-old embryos with 20% oxygen (optimum oxygen concentration). When the 9.5- and 10.5-day-old embryos were cultured for 24 h with too little or too much oxygen, retardation of the embryonic growth and abnormal development was observed. Using light microscopy, numerous degenerating cells, exhibiting granular deposits in the cytoplasm, were seen, but the distribution of the degenerating cells was quite different between the two groups. With electron microscopy, the most striking feature of the degenerating cells in the embryos cultured with too little oxygen, was the extreme swelling of the mitochondria without any morphological alterations of the nucleus or the other cell organelles. On the other hand, the characteristic feature of the degenerating cells in the embryos exposed to too much oxygen, was the formation of phagolysosomes in the cytoplasm. Morphological alterations of the nucleus or mitochondria were not evident. In the present study, the possible teratogenic mechanism of too much or too little oxygen in the whole-embryo culture of the rat embryo is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698664
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  • 13
    Electronic Resource
    Electronic Resource
    An ultrastructural and morphometric analysis of the Sertoli cell during the spermatogenic cycle of the rat (1988)
    Springer
    Anatomy and embryology 179 (1988), S. 191-203 
    Details
    ISSN: 1432-0568
    Keywords: Sertoli cell ; Spermatogenic cycle ; Ultrastructure ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of Sertoli cells from selected stages of the spermatogenic cycle was assessed by morphometric analysis which showed significant changes in the morphological features of Sertoli cell cytoplasm at the commencement of the cycle (stage II) compared to the middle (stages VII-VIII) and the completion of the cycle (stages IX-XIV). Total volume and surface area of organelles (rough and smooth endoplasmic reticulum (ER), lysosomes, mitochondria and Golgi) exhibited stage-dependent and cyclic variations as did the total surface area of Sertoli cell plasma membrane. Polarization of cytoplasmic organelles to basal or columnar regions of the Sertoli cell, exhibited particularly by the Golgi, rough ER and lysosomes also showed marked cyclic fluctuations during the spermatogenic cycle. Rough and smooth ER exhibited the most dramatic stage-dependent changes in total volume and surface area the former being respectively largest and smallest in stages VII-VIII and XIII-XIV, the latter organelle presenting the reverse pattern in these two groups of stages. Similar stage-dependent alterations of lysosome volume and surface area were also noted, being maximal during stages XIII-XIV-II and reaching a nadir at stage VIII. Although the functional role of most Sertoli cell organelles and inclusions remain largely unknown, the present study suggests that the cyclic and stage-dependent variations in ultrastructure probably reflect major changes in Sertoli cell function necessary for the regulation of the spermatogenic cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304701
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  • 14
    Electronic Resource
    Electronic Resource
    Ultrastructural observations in port wine stains (1988)
    Springer
    Archives of dermatological research 280 (1988), S. 338-345 
    Details
    ISSN: 1432-069X
    Keywords: Port wine stain ; Endothelium ; Basement membrane ; Collagen ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cause for the progressive vascular dilatation in port wine stains remains unclear. We compared the histology and ultrastructure of lesional and adjacent normal skin in paired biopsy specimens of 12 and 8 patients, respectively (age range, 6 to 53 years). In semithin sections, the lesions of all patients showed ectatic vessels and a fine-fibrous or hyaline thickening of the walls of postcapillary venules, as well as in some instances a loosening of the surrounding connective tissue. Ultrastructurally, the wall material consisted predominantly of peripheral deposits of amorphous material interspersed with collagen fibrils (diameter, 35±4 nm); occasionally the number of basal laminae in the inner part was also increased. Cross-banded filamentous aggregates with a periodicity of 95 nm were observed in and around the walls. The endothelium of many patients displayed fenestrations and/or small gaps. Various kinds of alterations of the intervascular connective tissue were found. We conclude that structural alterations of the vascular and later also of the intervascular connective tissue are related to the dilatation of the vessels. These findings are in agreement with the immunopathologically demonstrated increase of basement membrane components in the same biopsy specimens, but are interpreted as secondary phenomena. Endothelial stability and permeability may also be affected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00426611
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  • 15
    Electronic Resource
    Electronic Resource
    Ultrastructural pathology in emetine-induced myopathy (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 577-582 
    Details
    ISSN: 1432-0533
    Keywords: Cytoplasmic bodies ; Emetine ; Myopathy ; Sarcomeric lesions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Progressive myopathy developed in two women who consumed ipecac syrup containing emetine hydrochloride to induce vomiting as part of their anorexia nervosa. Muscle biopsy specimens were characterized by severe disruption of the sarcomeres. The ultrastructural spectrum extended from “Z-band streaming” to the formation of cytoplasmic bodies and also comprised abnormalities of the sarcotubular system, thus suggesting that muscle weakness may be related to both sarcomeric and sarcotubular lesions in this self-inflicted myopathy. It is tempting to suggest that muscle weakness may be correlated with or based on the pathology in sarcomeres and the sarcotubular system. As the myopathy is clinically reversible upon discontinuation of ipecac consumption the morphological findings should also be potentially reversible. Experimentally induced emetine myopathy may, thus, serve as a useful model to study morphological dynamics of sarcomeric lesions, which may be observed separately or simultaneously in a variety of spontaneously occurring human neuromuscular disorders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686202
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  • 16
    Electronic Resource
    Electronic Resource
    Ultrastructural study of chromatolytic neurons in an adult-onset sporadic case of amyotrophic lateral sclerosis (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 523-528 
    Details
    ISSN: 1432-0533
    Keywords: Amyotrophic lateral sclerosis ; Chromatolysis ; Ultrastructure ; Motor neuron disease ; Hyaline intraneuronal inclusions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural features of chromatolytic neurons observed in a sporadic case with amyotrophic lateral sclerosis (ALS) are reported. A 70-year-old woman died of weakness and atrophy of the four limbs, bulbar and facial muscles, and hyperreflexia, of 3 1/2 years' duration. Neuronal loss was marked in the anterior horn of the spinal cord, with degeneration of the pyramidal tracts. Most of the remaining neurons showed chromatolysis. Some of the chromatolytic neurons contained faintly eosinophilic inclusions with a halo. Few spheroids were observed. Hypoglossal nuclei, nucleus ambiguus, motor nuclei of N. VII and N.V were well populated, but contained several chromatolytic neurons. Ultrastructurally, the chromatolytic neurons contained aggregates of fibrils thicker than the 10-nm neurofilaments. These fibrils were arranged randomly, and were closely associated with granular materials as well as rough endoplasmic reticulum. Neurofilamentous accumulations reported to be common in sporadic ALS were rare in this case. No Bunina body was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687142
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  • 17
    Electronic Resource
    Electronic Resource
    A new type of cytoplasmic inclusion in human choroid plexus (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 11-16 
    Details
    ISSN: 1432-0533
    Keywords: Choroid plexus ; Cytoplasmic inclusion ; Histochemistry ; Ultrastructure ; Frequency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We described a new type of cytoplasmic inclusion in the choroidal epithelial cells of humans. The inclusions usually appeared as brown, round or elongated bodies with or without an inner core, ranging in size from 1.3 to 7.0 μm. Histochemically, they contained polysaccharides, proteins and compound lipids. Ultrastructurally, they were composed of finely granular and filamentous materials, which are densely packed in the inner core and less dense in the outer zone. The frequency study of the inclusions in 197 autopsied patients revealed that their occurrence had no correlation with the age or the disease category. It is concluded that the inclusions are a nonspecific, but peculiar, change of the choroidal epithelial cells, probably representing the morphological expression of a physiological or pathological alteration of the cellular metabolism at the single-cell level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687675
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  • 18
    Electronic Resource
    Electronic Resource
    Pathogenesis of pili annulati (1988)
    Springer
    Archives of dermatological research 280 (1988), S. 308-318 
    Details
    ISSN: 1432-069X
    Keywords: Pili annulati ; Ultrastructure ; DACM staining ; Hair cortex ; Protein metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Plucked scalp hairs and hair roots of pili annulati were examined to understand their pathogenesis. Stereoscopic examinations of hairs in transmitted light and/or reflected light and light microscopic surveys of the cross-sections of hairs confirmed that the cortical empty spaces appeared to be responsible to the unique dotted shiny appearance of the hairs seen by the unaided eyes under a refracted light. By transmission electron microscope, small vacuoles and dense bodies were observed in the cytoplasm of the differentiating cortical cells; subsequently, with increasing number of tonofilaments, an uneven distribution of free ribosomes occurred and abnormal spaces containing fine granular substances were formed in the cytoplasm of the cortical cells. Occasionally, extremely large cortical trichohyaline granules were found. In the keratinized hair, irregular empty spaces were present in the cortex of the abnormal hair segments. Histochemically, the keratinized cortex of the affected hairs always had more residual SH groups than the controls. Pili annulati may be a disorder of protein metabolism involving a partial dysfunction of cytoplasmic ribosomes, resulting in a lack of cortical keratin formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00440605
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  • 19
    Electronic Resource
    Electronic Resource
    Structural alterations of collagen fibrils in the reactive type of elastosis perforans serpiginosa (1988)
    Springer
    Archives of dermatological research 280 (1988), S. 319-322 
    Details
    ISSN: 1432-069X
    Keywords: Elastosis perforans serpiginosa ; Collagen fibrils ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00440606
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  • 20
    Electronic Resource
    Electronic Resource
    Effect of AF64A on the cholinergic systems of the retina and optic tectum of goldfish (1988)
    Springer
    Experimental brain research 70 (1988), S. 455-462 
    Details
    ISSN: 1432-1106
    Keywords: Cholinergic toxin ; Retina ; Optic tectum ; ChAT ; Ultrastructure ; Goldfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary AF64A, a presumed selective cholinergic neurotoxin has been used to study the effect on cholinergic systems of the goldfish retina and optic tectum. Toxin injection in the vitreum and in the optic tectum caused a selective decrease of choline acetyltransferase activity in both areas, while no significant decrease of glutamate decarboxylase and D-3H aspartate uptake were observed at different times after the injections. The effect was particularly dramatic in the retina of long term-injected animals, where choline acetyltransferase dropped to practically zero level. The ultrastructural analysis showed selective degeneration of some neurons in the amacrine and ganglion cell layer of the retina as well as of synaptic terminals and neuronal cell bodies in the optic tectum. The results favour a selective cholinotoxicity of AF64A in fish nerve tissue at doses substantially higher than those found to have additional unselective effects in mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247593
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  • 21
    Electronic Resource
    Electronic Resource
    Serotonin-immunoreactivity in the monkey lateral geniculate nucleus (1988)
    Springer
    Experimental brain research 69 (1988), S. 662-666 
    Details
    ISSN: 1432-1106
    Keywords: Serotonin ; Lateral geniculate nucleus ; Monkeys ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Serotonin-immunoreactivity in the monkey lateral geniculate nucleus appears as a plexus of fine, beaded fibers decreasing in density from magnocellular to parvocellular laminae. Ultrastructurally, these fibers show strictures and dilations, and are filled with dense round particles as well as granular material attached to outer mitochondrial membranes and microtubules. Most of the profiles followed in serial sections lack morphologically defined synapses. The few synapses observed are asymmetric, some with subjunctional dense bodies. This appearance suggests a possible excitatory effect mainly on interneurons which in turn would inhibit principal cells. Serotonin released non-synaptically may block the delivery of transmitters from retinal terminals and/or the receptors for such transmitters, thereby exerting a modulatory depressing action on principal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247318
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  • 22
    Electronic Resource
    Electronic Resource
    Estrogen-induced alterations in synaptic morphology in the midbrain central gray (1988)
    Springer
    Experimental brain research 69 (1988), S. 522-530 
    Details
    ISSN: 1432-1106
    Keywords: Estrogen ; Synapse ; Ultrastructure ; Midbrain central gray ; Lordosis behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Axons of ventromedial hypothalamic (VMH) neurons have been previously shown to terminate in the midbrain central gray (MCG) (Chung et al. 1984, 1986). Since VMH synapses in this region may be involved in the mediation of estrogen-induced lordosis behavior, we examined the effect of estrogen on the morphology of synapses in the MCG. Ovariectomized adult female rats were given daily subcutaneous injections of estradiol benzoate (10 μg) or the vehicle control and after 20 days of injection, only the estrogen-treated rats showed the lordosis response. A quantitative analysis of MCG tissue from these animals demonstrates morphological changes in various synaptic parameters with estrogen treatment including: 1) an increase in the mean number of dense-cored vesicles and an increase in the number of terminals containing densecored vesicles, 2) an increase in the length of postsynaptic densities (PSDs), 3) an increase in the number of PSDs showing perforations, 4) an increase in the number of synapses, and 5) an increase in the number of synapses with positive synaptic curvature. No alterations in the number of subjunctional bodies were observed. The dense-cored vesicles may contain an estrogen-induced trophic factor which may function in maintaining the integrity of postsynaptic processes and cells in the MCG with which VMN endings contact (Chung et al. submitted) and/or which induces morphological changes in postsynaptic structures which facilitate the effects of estrogen on lordosis behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247306
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  • 23
    Electronic Resource
    Electronic Resource
    Reinnervation of dopamine neurons by regenerating serotonin axons in the rat medial zona incerta (1988)
    Springer
    Experimental brain research 72 (1988), S. 473-480 
    Details
    ISSN: 1432-1106
    Keywords: Serotonin ; Tyrosine hydroxylase ; Zona incerta ; Regeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cellular relationships between serotonin (5-HT) axons and tyrosine hydroxylase (TH)-containing neurons were examined by combined (3H)5-HT uptake radioautography and TH immunocytochemistry in the medial zona incerta (ZI) of adult rats, 7 and 50 days after an intracerebral injection of 5,7-Dihydroxytryptamine (5,7-DHT). Seven days post-lesion, only rare, scattered (3H)5-HT-labeled axon terminals were apparent in the zone of the medial ZI accessible to intraventricularly injected (3H)5-HT. In contrast, in sham-injected animals (3H)5-HT-labeled varicosities were numerous and often observed adjacent to TH-immunoreactive perikarya and dendrites. Fifty days post 5,7-DHT injection, the density of (3H)5-HT-labeled terminals approximated that seen in sham-treated animals. At the ultrastructural level, these regenerated 5-HT axons were similar in size, shape and content to those observed in sham-operated rats. Also, as in sham, some of the (3H)5-HT-labeled axons were directly apposed to TH-immunopositive labeled profiles. The latter included large dendritic shafts and dendritic spines, but only rare perikarya. In both sham- and 5,7-DHT-treated animals a few of the contacts between (3H)5-HT-labeled and TH-immunoreactive profiles exhibited an asymmetric synaptic differentiation. These results indicate that 5-HT fibers in the medial ZI, following regeneration, can reestablish normal relationships and even synapses with a given population of chemically identified cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250592
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  • 24
    Electronic Resource
    Electronic Resource
    Pre-fertilization degeneration of both synergids in Brassica campestris ovules (1988)
    Springer
    Sexual plant reproduction 1 (1988), S. 208-216 
    Details
    ISSN: 1432-2145
    Keywords: Megagametophyte ; Synergids ; Brassica campestris ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Brassica campestris, both synergids of the ovule degenerate before the arrival of the pollen tube. Synergid degeneration does not depend on pollination. At the non-degenerated stage, the synergids are completely filled with a complexly organized cytoplasm containing numerous mitochondria with many cristae, a large number of dictyosomes with many associated vesicles, and a very extensive rough endoplasmic reticulum. The degenerative changes that occur in the cytoplasm of the synergids are characterized by a loss of visibility of the membranes of the endoplasmic reticulum and the simultaneous formation of dense deposits on the surrounding membranes of the mitochondria. Locally, the plasma membranes of the synergids disappear, and some ground plasma of the synergids penetrates into the space between the plasma membranes of the egg cell and the central cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189154
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  • 25
    Electronic Resource
    Electronic Resource
    Cadmium induced changes in cell organelles: an ultrastructural study using cadmium sensitive and resistant muntjac fibroblast cell lines (1988)
    Springer
    Archives of toxicology 62 (1988), S. 133-145 
    Details
    ISSN: 1432-0738
    Keywords: Cadmium ; Ultrastructure ; In vitro ; Nucleus ; Cytoplasm ; Muntjac
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A detailed electron microscopy study of cadmium sensitive and resistant muntjac fibroblast cell lines has identified a wide range of intracellular damage following exposure to cadmium. Damaged organelles included cell membrane, mitochondria, Golgi cisternae and tubular network, chromatin, nucleoli, microfilaments and ribosomes. Although cell membrane damage was generally the earliest indication of adverse cadmium action, particularly with continuous cadmium exposures, cells could tolerate extensive membrane loss. Mitochondrial distortion and some damage to Golgi was also tolerated. The turning point at which cadmium became lethal was generally marked by a cascade of events which included damage to both nuclear and cytoplasmic components. These results for fibroblasts are discussed and compared with damage reported in other types of cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570131
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  • 26
    Electronic Resource
    Electronic Resource
    Treatment of infantile phytanic acid storage disease: clinical, biochemical and ultrastructural findings in two children treated for 2 years (1988)
    Springer
    European journal of pediatrics 147 (1988), S. 133-142 
    Details
    ISSN: 1432-1076
    Keywords: Infantile Refsum disease ; Phytanic acid ; Dietary treatment ; Peroxisomes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two patients with infantile phytanic acid storage disease (infantile Refsum disease), one of whom showed the presence of morphologically normal peroxisomes in a liver biopsy, were treated with a low phytanic acid diet for more than 2 years and the effects of treatment on certain clinical, biochemical and ultrastructural parameters were examined. Both patients showed evidence of either an improvement or stabilisation in their clinical condition. Plasma phytanic acid levels decreased to near normal values in approximately 6 weeks after the introduction of the diet; plasma pipecolic acid also declined markedly but the decrease was not so rapid and its level remained abnormal. C26∶C22 fatty acid ratios decreased very slowly and even after 2 years the values remained grossly abnormal. Despite the marked reduction of phytanic acid in the liver, there was an increase in the C26∶C22 fatty acid ratios and this appeared to be paralleled by an increase in inclusion bodies. Our data suggest that some patients with the infantile form of Refsum disease may show some clinical benefit from dietary management and this is reflected biochemically by decreases in the plasma levels of phytanic acid and pipecolic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00442210
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  • 27
    Electronic Resource
    Electronic Resource
    Ultrastructural and cytochemical examination of the nuclear crystalloid inclusions of Olea europaea L. mesophyll cells (1988)
    Springer
    Trees 2 (1988), S. 261-266 
    Details
    ISSN: 1432-2285
    Keywords: Nuclear crystalloid inclusions ; Olea europaea ; Cytochemistry ; Ultrastructure ; Glycoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The nuclei of mesophyll cells of olive trees contain numerous sizeable crystalloid inclusions. Cytochemical examination using epoxy resin-embedded, semithin-sectioned tissue indicated the presence of proteins and oligoor polysaccharides in these inclusions. Their electron microscopical analysis revealed a crystalline substructure consisting of intersected subunits of high order. The spacing of the lattice fibrils and the angles of intersection were determined and used to establish a model of the unit cell of crystallization. It is suggested that the nuclear crystalloids of olive trees consist of glycoprotein molecules. They differ from the intranuclear crystalloids observed in other species predominantly in the high density of their subunit arrangement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202381
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  • 28
    Electronic Resource
    Electronic Resource
    Primary malignant astrocytoma of the cerebellum in children (1988)
    Springer
    Child's nervous system 4 (1988), S. 306-309 
    Details
    ISSN: 1433-0350
    Keywords: Malignant astrocytoma ; Glioblastoma ; Cerebellum ; Children ; Cytofluorometric DNA analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The case of a 1-year-old girl with primary malignant astrocytoma of the cerebellum is presented with special reference to ultramicroscopic study and cytofluorometric DNA analysis. The routine light microscopic study was not pathognomonic because of the immaturity of the composing cells. The glial fibrillary microfilaments characteristic of astroglial cells were confirmed by means of electron microscopy. Cytofluorometrically, the DNA histogram of this case revealed a prominent peak in the 4C region, with considerable dispersion to the 8C region, indicating the polyploidic and heterogeneic pattern of malignant tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271931
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  • 29
    Electronic Resource
    Electronic Resource
    Effects of chronic diabetes mellitus on the electrical and contractile activities,45Ca2+ transport, fatty acid profiles and ultrastructure of isolated rat ventricular myocytes (1988)
    Springer
    Pflügers Archiv 411 (1988), S. 564-572 
    Details
    ISSN: 1432-2013
    Keywords: Isolated cardiac myocytes ; Electrical activity ; Contraction ; Fatty acids ; Ultrastructure ; Diabetes mellitus, experimental ; Streptozotocin ; Electrophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of chronic experimental diabetes on electrophysiological properties, contractile behavior,45Ca2+ transport, fatty acid profiles and ultrastructural characteristics were studied in enzymatically dissociated ventricular myocytes. Diabetes was induced in rats by streptozotocin administration and animals were killed 8–10 weeks later. Myocytes from diabetic rats exhibited electrical behavior similar to that of myocytes from control rats, but their contractile properties were altered. Their sensitivity of the twitch contractions to various positive and negative inotropic agents (isoproterenol, norepinephrine, phenylephrine, acetylcholine, ouabain and veratridine) was greatly diminished. However, a part of the contractile response (the tonic, sustained contractions) were increased in the diabetic myocytes, indicating that the changes are not caused by a decreased sensitivity of myofilaments. Furthermore, the diabetic myocytes exhibited also significant decrease in total Ca2+ content. The fatty acid profile in the diabetic group was changed mainly in that there were slightly elevated levels of docosahexaenoic acid and diminished levels of palmitic acid. The ultrastructure of the diabetic myocytes was affected only slightly. These investigations offer for the first time a comprehensive picture of changes related to diabetic cardiomyopathy as they occur at the level of cardiomyocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582379
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  • 30
    Electronic Resource
    Electronic Resource
    Electron microscope localisation of insulin-like immunoreactivity of conventionally processed human insulinomas (1988)
    Springer
    Virchows Archiv 412 (1988), S. 443-450 
    Details
    ISSN: 1432-2307
    Keywords: Insulin ; Insulinomas ; Ultrastructure ; Immunogold technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Localisation of insulin-like immunoreactivity has been studied using the immunogold staining procedure on thin sections of 6 human insulinomas, conventionally processed for electron microscopy. The labelling was restricted to the secretory granules. Depending on their morphology, these either resembled B-cell granules of human adult pancreas or belonged to the atypical (non-diagnostic) group. Within the former group, those with a crystalloid core or an amorphous dense or moderately dense core were strongly immunoreactive, whereas others, filled with a pale material, were poorly labelled. Most granules of this type were stored together within the heavily granulated cells of 3 insulinomas, presenting the classical features of clinical and biological behaviour and a typical light microscopic staining pattern. In contrast, the non-diagnostic granules, characterized by their smaller size, a very dense core and a thin halo, were mainly found within the poorly granulated cells making up the other tumours, and showed a very uneven labelling. Strongly labelled granules were found in one insulinoma that also belonged to the classical type; these were stored together with a few diagnostic granules within the same cells. Only poorly labelled atypical granules were present in two cases revealing a number of unusual features; these included moderate elevation of insulinaemia, uncertain tumour histology, as well as weak immunostaining for insulin/proinsulin and variable argyrophilia of the tumour in paraffin sections. These findings suggest that human insulinomas differ not only in storage capacity but also in their degree of granule maturation. This may involve some deficiency of either the prohormone conversion or the subsequent processing of the cleavage products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750578
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  • 31
    Electronic Resource
    Electronic Resource
    Lipid detection by malachite green-aldehyde in the dental basement membrane in the rat incisor (1988)
    Springer
    Cell & tissue research 253 (1988), S. 685-687 
    Details
    ISSN: 1432-0878
    Keywords: Basement membrane ; Lipids ; Ultrastructure ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Developing rat incisors were treated with malachite green-aldehyde fixative solution (MGA), which retains and stains lipids. We observed positive staining occurring as dots in the basement membrane. Most of these dots (2–3.5 nm in diameter) were grouped in the lamina densa but some were also present in the lamina lucida and the lamina fibroreticularis. These data provide evidence for the existence of lipids in the dental basement membrane and suggest that they are distributed together with the various groups of proteins so far detected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219762
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  • 32
    Electronic Resource
    Electronic Resource
    Catecholaminergic nerves in the embryonic chick ovary: co-localization with β2-adrenoceptor-bearing steroidogenic cells (1988)
    Springer
    Cell & tissue research 254 (1988), S. 1-9 
    Details
    ISSN: 1432-0878
    Keywords: Adrenergic nerves ; Steroidogenic cells ; Embryonic ovary ; β 2Adrenoceptors ; Cytochemistry ; Ultrastructure ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study investigates the innervation of the embryonic chick ovary with regard to (i) development and compartmentalization of catecholaminergic nerves, and (ii) presence of adrenoceptors on steroidogenic target cells of catecholaminergic nerve terminals. Catecholaminergic nerve fibers visualized by glyoxylic acid-induced histofluorescence first appeared at embryonic day (E) 13. From E15 through E21 the density of fluorescent aminergic nerves increased markedly in parallel with the concentration of catecholamines and numbers of nerve bundles and single axons seen at the electron-microscopic level. Catecholaminergic nerves were confined to the ovarian medulla and closely associated with interstitial cells. Nerve terminals approached interstitial cells up to a distance of 20 nm and, in their majority, exhibited uptake of the false adrenergic transmitter 5-hydroxydopamine. Although adrenaline amounted to 14% of the total catecholamine content at E21, adrenaline immunoreactivity was only detected in adrenal chromaffin cells, but not in nerve fibers or cell bodies within the ovary. Interstitial cells structurally matured between E15 and E21 as documented by an increase of smooth endoplasmic reticulum and tubular mitochondria. Monoclonal antibodies mAB 120 and BRK 2 raised against avian β 1 and mammalian β 2-adrenergic receptors revealed the presence of β 2-adrenoceptor-like immunoreactivity on the surface of interstitial cells, but not on any other cell type. The results are consistent with the notion of a dense adrenergic innervation of the embryonic chick ovarian medulla and its steroidogenic interstitial cells, and suggest the chick ovary as an excellent model for elucidating the functional role of a neural input to steroidogenic cells during development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220010
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  • 33
    Electronic Resource
    Electronic Resource
    The pattern of organization of intermediate filaments and their asymmetrical association with dense bodies in smooth muscle of an ascidian Halocynthia roretzi (1988)
    Springer
    Cell & tissue research 252 (1988), S. 23-32 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Intermediate filaments ; Dual network ; Ultrastructure ; Ascidian ; Halocynthia roretzi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An extensive network of intermediate filaments that interconnected cytoplasmic dense bodies and connected the dense bodies to the cell surface was revealed in double-fixed, tannic acid-stained preparations of ascidian smooth muscle. The filament network ran through spaces in the continuous network of myofibrils, connecting them longitudinally, obliquely and transversely to form an intimately associated, dual network. In their transverse passage, the intermediate filaments ran across myofibrils along I-zones exclusively, interconnecting successive dense bodies. The pattern of attachment of intermediate filaments to dense bodies was predominantly “one-sided.” The filaments, which themselves were not incorporated into the contractile apparatus, remained folded or unfolded between myofibrils and between sarcomere-like structures in synchrony with the contraction-relaxation cycles. These results suggest that the intermediate filaments mechanically maintain the organization and arrangement of myofibrils via an intimate association with the myofibrils in the regions of the dense bodies, in such a way that the filaments do not impede muscle function. Based on these observations, a new model for the network of intermediate filaments in smooth muscle cells is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213822
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  • 34
    Electronic Resource
    Electronic Resource
    Ultrastructure of the tentacles of the apodous holothurian Leptosynapta spp (Holothurioidea: Echinodermata) with special reference to the epidermis and surface coats (1988)
    Springer
    Cell & tissue research 251 (1988), S. 387-397 
    Details
    ISSN: 1432-0878
    Keywords: Tentacles ; Ultrastructure ; Adhesion ; Leptosynapta spp (Holotheorie) ; Echinodermata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tentacles of the apodous holothurian Genus Leptosynapta have been studied by use of transmission and scanning electron microscopy. The gross anatomy, water vascular system, fibre systems and ectoneural nerve ring are described. A fuzzy coat of attenuated filaments covers the surface of the tentacle, broken only by secretory ducts. A cuticle underlies the fuzzy coat. Bacteria are common in the subcuticular space. Fixation without osmium gives poor preservation of the surface coats. The epidermis consists of a single layer of columnar cells consisting of Type-1, Type-2, support, goblet and uniciliated cells. Type-1 cells secrete electron-dense material and appear to be homologous to adhesive cells of the tentacles of other holothurians. The support cells contain large, granular vesicles not found in other holothurians. Goblet cells contain flocculent mucus and have an apical cilium. Goblet cells are not found in other holothurian tentacles and may function to lubricate and wrap adhering particles to aid their ingestion. The uniciliated cells are rare, poorly developed and the cilium does not extend past the cuticle. The ultrastructure of the tentacles is discussed in relation to those of other holothurians.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215848
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  • 35
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    Electronic Resource
    The ultrastructure of the lung of two newborn marsupial species, the northern native cat, Dasyurus hallucatus, and the brushtail possum, Trichosurus vulpecula (1988)
    Springer
    Cell & tissue research 252 (1988), S. 683-685 
    Details
    ISSN: 1432-0878
    Keywords: Lung ; Ultrastructure ; Marsupial ; Newborn ; Surfactant ; Dasyurus hallucatus, Trichosurus vulpecula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lungs of newborn northern native cats, Dasyurus hallucatus and newborn brushtail possums, Trichosurus vulpecula were examined by both light and electron microscopy. The native cat has a birth weight of 18 mg after a gestation of about 21 days, whereas the brushtail possum weights 200 mg at birth and has a gestation period of 17.5 days. The lungs of the native cat are two large respiratory sacs, with a respiratory lining of squamous cells and surfactant-secreting cells. The capillaries are located within the connective tissue just below this respiratory epithelium. The visceral covering of the lung is formed by squamous cells. The lungs of the possum are composed of numerous large respiratory sacs which are separated by connective tissue septa in which the capillaries are located. The sacs, as in other species, are lined with squamous cells and surfactant secreting cells. It is proposed that the structure of the lung of the newborn marsupial is related more to the size of the newborn rather than to the length of the gestation period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216657
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  • 36
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    Electronic Resource
    Vascular response in a non-uterine site to implantation-stage embryos in the rat and guinea-pig: in vivo and ultrastructural studies (1988)
    Springer
    Cell & tissue research 254 (1988), S. 217-224 
    Details
    ISSN: 1432-0878
    Keywords: Implantation ; Embryo ; Ultrastructure ; Vasculature ; Rat (Sprague-Dawley) ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Preimplantation-stage embryos were transferred to the anterior eye chamber of recipient rats and guinea-pigs. After implantation had occurred the influence of the embryo on the iris vasculature was examined ultrastructurally. In both species, the earliest effect of embryonic implantation was an increased stromal oedema. Under increasing embryonic influence the vascular endothelial cells showed an increased number of projections into the vascular lumen, while in the rat, endothelial projections were also found pushing back into the basement membrane. In the rat, the endothelium became very irregular in thickness prior to complete disintegration and loss during more advanced stages of implantation. Rat embryonic trophoblast was found invading iris vasculature, particularly in areas where the iridial endothelium was partially or completely missing. Other cells in the iris, including the stroma, appeared to be less affected. In the guinea-pig, however, trophoblast cells appeared to be capable of invading the vasculature by displacing endothelial cells that still appeared morphologically normal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220037
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  • 37
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    Electronic Resource
    Morphological, histochemical, and ultrastructural characterization of the accessory cells of neuromasts in the salamander Pleurodeles waltlii (1988)
    Springer
    Cell & tissue research 254 (1988), S. 233-240 
    Details
    ISSN: 1432-0878
    Keywords: Lateral-line sense organs ; Mechanoreceptors ; Supporting cells ; Ultrastructure ; Pleurodeles waltlii (Urodela)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural and histochemical features of the accessory cells of the neuromast of the salamander P. waltlii have been examined. Three types of accessory cells, supporting, mantle, and basal, were found, but only the first 2 are considered in this article. Supporting cells characterized by a highly dilated endoplasmic reticulum occur among and surrounding sensory cells. Mantle cells, morphologically different from the supporting cells, surround the remainder of the neuromast. Both types of accessory cells exhibit histochemically different secretory materials. Our morphological results suggest that both accessory cells contribute to the formation of cupular material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220039
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  • 38
    Electronic Resource
    Electronic Resource
    Influence of a short light pulse at night on the ultrastructure of the rat pinealocyte: a quantitative study (1988)
    Springer
    Cell & tissue research 254 (1988), S. 247-249 
    Details
    ISSN: 1432-0878
    Keywords: Pinealocyte ; Light exposure ; Ultrastructure ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Although it is generally known that light strongly influences N-acetyltransferase activity and melatonin production in the pineal gland, little information is available concerning morphological changes following light exposure. As exposure of rats to a short light pulse at night rapidly depresses melatonin synthesis, we decided to determine whether this experimental condition produces rapid changes in the pinealocyte organelles. A 30-min light pulse at night (six hours after lights out) provoked rapid changes in the relative volumes of some pinealocyte organelles. The volume fractions of mitochondria, Golgi apparatus and lipid droplets, and the numbers of dense-core vesicles and “synaptic” ribbons decreased, whereas the volume fraction of lysosomes increased. There were no differences in the volumes of granular endoplasmic reticulum and vacuoles containing flocculent material in those animals exposed to light compared with control animals. These results indicate that a short light pulse at night causes ultrastructural changes that can be interpreted as morphological features of diminished activity of pinealocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220041
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  • 39
    Electronic Resource
    Electronic Resource
    Neurosecretory centers from the eyestalk of Siriella armata M. Edw. (Crustacea: Mysidacea): ultrastructural variations during normal and experimentally inhibited molt cycle (1988)
    Springer
    Cell & tissue research 254 (1988), S. 381-391 
    Details
    ISSN: 1432-0878
    Keywords: X-organ ; Sinus gland ; Ultrastructure ; Cyclic activity ; Siriella armata (Crustacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the medulla interna-medulla externa X-organ (MI-ME Xo)-sinus gland (SG) complex in the eyestalk of Siriella armata is described during the normal and the experimentally inhibited molt cycle. In the normal SG, four types of neurosecretory axon terminals, each containing distinguishable neurosecretory granules, can be described. Thus, type-2 granules are synthesized by G1 neurons forming the MI-ME Xo. The cell bodies and axonal endings of these cells in the sinus gland have been examined at the following molt stages: intermolt (stage C4), premolt (D0 and D2), and postmolt (A1, A2 and B). Changes in ultrastructure of the G1 cells have been monitored and correlated to inhibitions of the molt-and reproductive cycle produced by electrocauterization of the MI-ME Xo. The results obtained suggest that the neurosecretion from the G1 cells exerts a positive influence on molt and brood preparation. The occurrence of a distal group of G1 cells whose axons terminate at a different site from the SG suggests that the neural factors of the MI-ME Xo are diverse and control different physiological activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225810
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  • 40
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    Electronic Resource
    Study of neuropeptide Y-containing nerve fibers in the human penis (1988)
    Springer
    Cell & tissue research 254 (1988), S. 69-74 
    Details
    ISSN: 1432-0878
    Keywords: Neuropeptide Y (NPY) ; Penis erection ; Perivascular nerve fibers immunocytochemistry ; Ultrastructure ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neuropeptide Y 1–36 (IR-NPY) immunoreactive nerve-fiber processes have been observed in tunicae of veins and arteries and in smooth muscles of the human penis taken at autopsy or during surgery by use of light-and electron-microscopic immunohistochemical techniques. Numerous IR-NPY nerve fibers were mostly concentrated in the inner part of the adventitia close to the media of the arterial and venous vessels and among the intracavernous smooth muscle cells. IR-NPY nerve fibers were less abundant in veins than in arteries. Positive somata were not observed in the penises. At the ultrastructural level, IR-NPY were localized exclusively in large, dense granules of nerve terminals by means of the postembedding immunogold technique. In the deep dorsal vein, IR-NPY nerve fibers were also located in the media formed by an outer circular and an inner longitudinal layer. In the intracavernous and dorsal arteries, they showed the highest density in the inner part of the adventitia. In the corpora cavernosa and in the corpus spongiosum, IR-NPY nerve processes were intermingled between the smooth-muscle fibers around the sinusoid spaces. IR-NPY nerve fibers were present in the cavernous nerves close to the central arteries. The urethra did not show any IR-NPY-positive nerve fibers. This peculiar distribution of IR-NPY nerve fibers suggested that they could participate in regulating arterial and venous blood flow and intracavernous smooth-muscle tone. NPY may therefore be of importance in some of the mechanisms of penile erection especially during detumescence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220018
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    Electronic Resource
    Implantation of cultured thymic fragments in congenitally athymic (nude) rats (1988)
    Springer
    Cell & tissue research 254 (1988), S. 283-294 
    Details
    ISSN: 1432-0878
    Keywords: Thymus ; Cultured thymic fragments ; Epithelial cells ; Microenvironment ; Ultrastructure ; Rat (nude)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cultured thymic fragments correspond to the thymic microenvironment depleted of lymphocytes and dendritic cells. When these fragments are implanted under the kidney capsule of congenitally athymic rats, lymphocytes and dendritic cells of host origin enter the graft and induce thymus-dependent immunity in the recipient. This paper describes the ultrastructure of the fragments and the changes that occur during the restoration of normal thymic architecture. At the end of the culture period of 6–9 days and in the early stages after implantation, the grafts consist of keratin-containing epithelial cells of unusual morphology that can be labelled with antibodies raised against the epithelium of the mid/deep cortex and the subcapsule/medulla. Normal thymic architecture develops, including nerves and blood vessels, as lymphocytes populate the environment, and by 4–6 weeks the epithelial cells are the same phenotypically and ultrastructurally as those found in normal rat thymus. However, some areas without lymphocytes still contain the atypical epithelial cells seen before implantation. Large multinucleated giant cells are also present with a few associated epithelial cells of subcapsular/medullary phenotype. In conclusion, the cultured thymic fragments contain a hitherto unknown precursor epithelial cell with an atypical ultrastructure and phenotype that is not seen in normal development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225801
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  • 42
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    Electronic Resource
    An ultrastructural study of mitosis and cytokinesis in normal ‘resting’ human breast (1988)
    Springer
    Cell & tissue research 252 (1988), S. 581-587 
    Details
    ISSN: 1432-0878
    Keywords: Normal resting breast ; Ultrastructure ; Mitosis ; Cytokinesis ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parenchyma of the normal “resting” human breast was examined by electron microscopy to characterize the cells undergoing mitosis and the mechanism by which the normal tissue architecture is maintained during this process. In this study of 112 mitotic cells, it was found that the mitotic cells were luminally positioned, polarised epithelial cells with no evidence of myoepithelial cell division. Ultrastructurally, the nuclear and cytoplasmic changes were consistent with previous reports of mitosis in other tissues. However, unlike all previous reports, two specific orientations of the nuclear spindle and thus the planes of cytokinesis were observed. In a few cases the spindle formed parallel to the lumen and division resulted in two luminally positioned daughter cells. However, in the majority of mitotic cells the spindle was approximately at right angles to the lumen and this orientation resulted in a luminally and a basally positioned daughter cell. It is proposed that the abnormally positioned basal daughter cell could develop into a myoepithelial cell or undergo deletion (apoptosis). Thus the two orientations of mitosis may explain the mechanism by which the epithelial and myoepithelial cell populations were maintained by a single progenitor cell without disrupting the integrity of the tissue architecture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216645
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    Electronic Resource
    Ultrastructure of the ovarian medulla in the newly hatched chick treated with human chorionic gonadotropin (1988)
    Springer
    Cell & tissue research 253 (1988), S. 665-670 
    Details
    ISSN: 1432-0878
    Keywords: Ovary ; Steroid-secreting cells ; Ultrastructure ; Chorionic gonadotropin ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of the ovarian medulla of the newly hatched white leghorn chick were studied in control animals and compared with chicks that were treated with human chorionic gonadotropin during embryonic development. The ovarian medulla was mainly occupied by epithelial cells which formed cords or islets surrounded by a basal lamina. Within this epithelial compartment, steroidogenic cells, poorly differentiated cells and a lacunary system could be recognized. When chicks were treated with human chorionic gonadotropin, steroidogenic cells became discernible; there was an increment in the amount of cytoplasm and the area of mitochondria. Poorly differentiated cells exhibited signs of stimulation, and transitional images suggested the transformation of these cells into steroidogenic cells. The epithelial cells of the lacunar system also displayed stimulated cytoplasmic organelles. Evidence was supplied suggesting that relatively undifferentiated cells persist in the ovarian medulla until hatching and can develop into steroidogenic cells under gonadotropic stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219758
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  • 44
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    Electronic Resource
    Electron-microscopic immunocytochemistry of 5-hydroxytryptamine in the ascidian endostyle (1988)
    Springer
    Cell & tissue research 253 (1988), S. 137-143 
    Details
    ISSN: 1432-0878
    Keywords: Endostyle ; Ultrastructure ; Immunocytochemistry ; 5-Hydroxytryptamine ; Granules ; Ciona intestinalis ; Corella parallelogramma, (Tunicata) ; Ascidia mentula (Tunicata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cellular and subcellular distribution of serotonin (5-hydroxytryptamine, 5-HT) in the endostyle of three species of ascidians, Ciona intestinalis, Corella parallelogramma, Ascidia mentula, was studied by light-(immunoperoxidase) and electron-microscopic (immunogold) immunocytochemistry. At the light-microscopic level 5-HT-like immunoreactivity (5-HT-LI) was exclusively found in cells located in the lateral portion of the endostyle, between zone 7, known to have iodinating capacity, and zone 8, which consists of ciliated cells. At the electron-microscopic level, the 5-HT-immunoreactive cells were found to correspond to cells containing polymorphous, dense granules, 100–300 nm in diameter. The granules were located in the supranuclear cytoplasm facing the endostyle lumen as well as in the infranuclear cytoplasm facing the extracellular space. Quantification showed that the 5-HT-LI was considerably higher (13–67 times) in cytoplasmic areas containing granules as compared to areas devoid of granules. Most, but not all, of the 5-HT-LI was associated with the dense core of the granules. In conclusion, serotonin-containing cells are located in the peripheral portion of the endostyle, between zones 7 and 8. Serotonin is stored in cytoplasmic granules that are present both in the apical and basal cytoplasm. This suggests the possibility that the cells are bipolar and secrete serotonin both in a basal direction to the extracellular space, and in an apical direction to the pharyngeal lumen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221748
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  • 45
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    Electronic Resource
    Effect of live and heat-killed bacteria on the secretory activity of Paneth cells in germ-free mice (1988)
    Springer
    Cell & tissue research 251 (1988), S. 87-93 
    Details
    ISSN: 1432-0878
    Keywords: Paneth cells ; Ultrastructure ; Morphometry ; Facultative anaerobes ; Germ-free mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Germ-free mice were given live or heat-killed facultative anaerobes, and the ultrastructure of ileal Paneth cells was quantitatively examined with special reference to secretory granules showing a bipartite substructure (central core and peripheral halo). After administering live or heatkilled bacteria, there was a decrease in the area occupied by the cores of secretory granules in Paneth cells, and exocytosed core material was observed in the crypt lumen. There were no changes in the area occupied by the halo of secretory granules. None of the examined Paneth cells phagocytosed bacteria. It is concluded that certain bacteria may affect the secretion of antibacterial agents contained in the secretory granules of Paneth cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215451
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  • 46
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    Electronic Resource
    Three-dimensional organization of the plasmalemmal vesicular system in directly frozen capillaries of the rete mirabile in the swim bladder of the eel (1988)
    Springer
    Cell & tissue research 254 (1988), S. 17-24 
    Details
    ISSN: 1432-0878
    Keywords: Endothelium ; Swim bladder ; Capillaries ; Vesicles ; Ultrastructure ; Cryofixation ; Anguilla rostrata (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Several recent studies comparing chemically fixed and cryofixed endothelium have indicated that glutaraldehyde fixation may result in increases in the population of “vesicles” in the cytoplasm. Other reports based on ultrathin serial-section reconstruction of chemically fixed endothelium have revealed that the vesicular system is comprised of interconnected membranous compartments, which are ultimately continuous with either cell surface but do not extend across the endothelial cell. In this study, we have investigated the three-dimensional organization of the vesicular system in directly frozen, freeze-substituted capillaries of the rete mirabile from the swim bladder of the eel, specifically using the same block of embedded capillaries in which frozen capillaries had previously been found to contain less “vesicles” than chemically fixed capillaries. The results show that essentially all vesicles remain inter-connected with each other and are part of two separate sets of invaginations from the luminal and abluminal cell surface like in chemically fixed tissue. Any increase in vesicle number resulting from glutaraldehyde fixation does not affect the overall three-dimensional organization of the vesicular system in these endothelial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220012
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    Electronic Resource
    Changes in proteins synthesized by rabbit endometrial epithelial cells following primary culture (1988)
    Springer
    Cell & tissue research 252 (1988), S. 123-132 
    Details
    ISSN: 1432-0878
    Keywords: Uterine epithelium ; Cell culture ; Proteins ; Ultrastructure ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological and biochemical changes occurring in rabbit endometrial epithelial cells when placed in culture were investigated. Cells were examined by scanning- and transmission electron microscopy and freeze-fracture. Morphologically, cultured cells are shorter and broader than the columnar epithelial cells in vivo, but retain their polarity as indicated by the presence of apical microvilli and a well-developed junctional belt. To study changes in biochemical function, proteins synthesized by cells in primary culture were analyzed by two-dimensional gel electrophoresis. Proteins were labeled during a 24-h incubation with 35S-methionine and gels examined by fluorography. The pattern of proteins changed after cells had been in culture for 48 h. On day 3 new proteins were synthesized and several protein species labeled during days 1 or 2 of culture, including uteroglobin, no longer appeared. On days 3–8 of culture the protein patterns were similar. Addition of progesterone, estradiol, prolactin, or combinations of these hormones to the culture medium for 24–144 h failed to elicit consistent changes in the pattern of labeled proteins established after 3 days of culture. Minor differences in protein patterns among unrelated cultures appear to have been derived from the original cells of the culture. These results indicate that after 48 h in primary culture, cells grown in vitro resemble endometrial epithelial cells morphologically, but no longer reflect functionally the character of epithelial cells in the uterus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213833
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    Electronic Resource
    Formation of desmosomes and other contact specializations in cultured skin of the frog (Rana esculenta) (1988)
    Springer
    Cell & tissue research 252 (1988), S. 157-163 
    Details
    ISSN: 1432-0878
    Keywords: Frog skin culture ; Desmogenesis ; Interdigitations ; Lamellipodia ; Ultrastructure ; Rana esculenta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Small trypsinized explants from ventral skin of frogs (Rana esculenta) were maintained in culture for 4 days during which a newly formed epithelium differentiated along the cut edges of the dermis. During the first 6 h adjacent cells produced numerous interdigitating lamellipodia. After 2 days, epithelial polarity was restored by the formation of zonulae occludentes and the epithelial cells were joined by a few small newly formed desmosomes and by numerous interdigitations. Bipartite junctional complexes consisting of a zonula occludens, followed by a series of typical desmosomes, and characteristic of adult frog epidermis were formed only after 4 days. When cultured in the presence of an inhibitor of protein synthesis (cycloheximide) the trypsinized epidermis no longer formed desmosomes. Therefore pools of one or more crucial desmosomal proteins must be very low or non-existent. However, cycloheximide did not prevent the formation of cell contact specializations, consisting of a highly developed system of complex lamellar interdigitations, between adjacent cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213837
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    Electronic Resource
    Morphology of smooth muscle cells in the rat thoracic duct (1988)
    Springer
    Cell & tissue research 251 (1988), S. 243-248 
    Details
    ISSN: 1432-0878
    Keywords: Thoracic duct ; Smooth muscle cell ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The three-dimensional cytoarchitecture and ultrastructure of the smooth muscle cells in the wall of the rat thoracic duct were investigated by scanning and transmission electron microscopy. The muscle layer basically consists of a single layer of circularly arranged cells. The smooth muscle cell is fusiform or ribbon-like in shape, as in veins or venules with a similar or smaller diameter. Connections by spinous processes are observed between adjacent muscle cells along their length. Spot-like membrane contacts frequently occur in areas where facing membranes are closely apposed. These are thought to be gap junctions and may be responsible for electrical coupling and mechanical attachment. Large invaginations arranged regularly in rows on the surface of the smooth muscle cells can be observed. These invaginations are closely associated with a flattened sarcoplasmic reticulum, and caveolae tend to open into the invaginations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215831
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  • 50
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    Electronic Resource
    Atropine inhibits the degranulation of Paneth cells in ex-germ-free mice (1988)
    Springer
    Cell & tissue research 253 (1988), S. 397-402 
    Details
    ISSN: 1432-0878
    Keywords: Paneth cells ; Ultrastructure ; Morphometry ; Atropine ; Germ-free/Ex-germ-free ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies have shown that the secretory products of Paneth cells contain antibacterial agents (lysozyme, IgA) that are affected by the bacterial milieu in the intestine. To investigate whether Paneth-cell secretion is controlled via cholinergic mechanisms, the ultrastructure of Paneth cells was studied in four animal groups: (1) germfree (GF) control mice (Jcl: ICR [GN], male, 13 weeks old), (2) GF mice injected subcutaneously with atropine sulfate (200 mg/kg body weight, dissolved in physiological saline 20 mg/ml), (3) ex-GF mice inoculated with feces from specific-pathogen-free (SPF) mice, and (4) ex-GF mice injected with atropine and inoculated with feces from SPF mice. In ex-GF mice inoculated with feces, 70–90% of the Paneth cells showed fewer secretory granules than those from GF mice (p〈0.01). Approximately 30% of the Paneth cells had a large vacuole (3–10 μm diameter) in the apical cytoplasm. Exocytosed electron-dense material from secretory granules was observed in a few crypt lumens. In ex-GF mice inoculated with feces and given atropine, about 90% of the Paneth cells contained numerous secretory granules, like those in GF control mice, but vacuolated Paneth cells and exocytotic figures were rare; thus the secretion of Paneth cells was blocked by atropine. It is therefore possible that the bacterial milieu in the intestine affects the secretory activity of Paneth cells via cholinergic mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222296
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    Electronic Resource
    Lymphocytes of the intestinal mucosa of chickens (1988)
    Springer
    Cell & tissue research 251 (1988), S. 189-195 
    Details
    ISSN: 1432-0878
    Keywords: Lymphocytes ; Epithelium ; Mast cells ; Granular leukocytes ; Basophils ; Ultrastructure ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination, by light and electron microscopy, of the morphology and the staining properties of intraepithelial lymphocytes from the intestine of the chicken revealed a population of lymphoid cells, of which a proportion (up to 20%) is granulated. The majority of cells were immunoreactive with anti-T cell serum and can therefore be considered to be related to T-lymphocytes, but they did not proliferate when cultured with phytohaemagglutinin. The granulated cells were identical to those previously designated globule-containing leukocytes, but were distinct from mast cells in their morphology, staining reactions and the stability of the granules in different fixatives and buffers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215464
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  • 52
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    Electronic Resource
    Structural changes produced in Kupffer cells in the rat liver by injection of lipopolysaccharide (1988)
    Springer
    Cell & tissue research 251 (1988), S. 205-214 
    Details
    ISSN: 1432-0878
    Keywords: Kupffer cells ; Granulocytes ; Ultrastructure ; Lipopolysaccharide ; Liver ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of Kupffer cells has been studied at various times after an intravenous injection of lipopolysaccharide of Salmonella abortus equii. The most prominent effects were: an increase in the number and dimensions of phagocytic vacuoles (often containing ingested LPS and neutrophilic granulocytes); mitochondrial damage, including disintegration of the matrix and cristae; an increase in the amount of dilated, lucent rough endoplasmic reticulum; presence of fat droplets in the cytoplasm. Five days after injection of lipopolysaccharide, the Kupffer cells had resumed their normal ultrastructure. Several minutes after injection of lipopolysaccharide, platelets adhered to the Kupffer and endothelial cells. Between one and six hours, neutrophilic granulocytes accumulated in the liver sinusoids. The resulting obstruction of the hepatic microcirculation most probably affected cellular ultrastructure by ischaemia. At three days, the number of Kupffer cells was doubled, and increased further at later time intervals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215466
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    Electronic Resource
    Melanophore death and disappearance produces color metamorphosis in the polychromatic Midas cichlid (Cichlasoma citrinellum) (1988)
    Springer
    Cell & tissue research 253 (1988), S. 9-14 
    Details
    ISSN: 1432-0878
    Keywords: Chromatophores ; Color change ; Ultrastructure ; Melanophores ; Macrophages ; Xanthophores ; Cichlasoma citrinellum (Teleostei: Cichlidae)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We describe the histological basis of color metamorphosis in the polychromatic Midas cichlid, Cichlasoma citrinellum. Eight percent of the individuals in a natural population transform from gray with black markings to orange, simultaneously losing their ability to adjust coloration in response to background and social context. This trait is inherited. Light- and electron microscopy revealed that this transformation is a two-step process. First, the melanophores die, then macrophage-like cells remove the debris. As a result of this initial process, the underlying xanthophores become visible, producing the orange coloration. A similar process may occur in individuals that further transform to white, or go directly from gray to white.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221733
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  • 54
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    Cortical cytoskeleton of the flagellateProteromonas lacertae: Interrelation between microtubules, membrane and somatonemes (1988)
    Springer
    Protoplasma 142 (1988), S. 46-54 
    Details
    ISSN: 1615-6102
    Keywords: Cytoskeleton ; Plasma membrane ; Microtubules ; Ultrastructure ; Freeze-fracture ; Flagellates ; Proteromonas lacertae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The anterior half of the cell surface of the parasitic flagellateProteromonas lacertae is corrugated while the posterior half is covered by hair-like appendages, called somatonemes. In the anterior part, the cortical microtubules are lined by a zig-zag shaped microfibril. Here, these two structures seem to be separated from the plasma membrane. In the posterior half of the cell the somatonemes, analogous to the mastigonemes of chrysophytes, are anchored to the cortical microtubules by paired small deposits of dense material. This was clearly demonstrated by Triton X 100 treatment which solubilized the plasma membrane but left the somatonemes attached to the cortical microtubules. Freeze-fracture images revealed the alignment of clustered intramembrane particles on the P-face of the plasma membrane which correspond to the attachment sites of the somatonemes, seen as dots in thin sections. The ER-derived membrane-associated somatonemes are probably linked to the cortical microtubules by anchoring proteins which are part of the plasma membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273225
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    Electronic Resource
    Observations of soybean root meristematic cells in response to heat shock (1988)
    Springer
    Protoplasma 144 (1988), S. 1-9 
    Details
    ISSN: 1615-6102
    Keywords: Heat shock ; Soybean root ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Soybean seedlings (Glycine max) were incubated in narrow temperature regimes to study the effects of heat shock on cell structures. The incubation temperatures used were as follows: 1. 28 °C (2h); 2. 40 °C (2h); 3. 45 °C (2h); 4. 40 °C (2h)→45 °C (2h); 5. 47. 5 °C (10 min); 6. 40 °C (2h)→47. 5 °C (10 min). Both optical and electron micrographs were taken of the different tissues of root meristems as they responded to heat shock. Cells of roots heated to 45 °C (2h) or 47.5 °C (10 min) with lethal treatment showed drastic heat injuries:e.g., membrane damage, coagulated plasmolysis, protoplasmic contraction, and leakage of cell content. Nucleolar segregation occurred in cells treated at both lethal and supraoptimal temperatures. Seedlings preincubated at 40 °C (2 h) became thermo-tolerant to lethal temperature treatment of 45 °C (2 h) or 47.5 °C (10 min), by protecting the plasmalemma, mitochondria, plastids and nuclei from heat damage. Without preincubation, however, these structures were destroyed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320274
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  • 56
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    Metabolism of P-particles (polysaccharide particles) in mature pollen grains ofEryngium campestre L. (Apiaceae) (1988)
    Springer
    Protoplasma 146 (1988), S. 65-71 
    Details
    ISSN: 1615-6102
    Keywords: Apiaceae ; Eryngium campestre ; Metabolism ; Pollen grain ; P-particle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The metabolism of P-particles (polysaccharide particles) was investigated in mature pollen grains ofEryngium campestre L. Numerous P-particles, originating from dictyosome activity, are found to be accumulated near the apertures, followed by mitochondria. A single layer of ER profiles seems to prevent the fusion of the P-particles with the intine. Instead of this, they fuse with each other forming nonmembrane-bounded polysaccharide-aggregates, which subsequently change their granulated structure to an amorphous. Mitochondria together with small vesicles are involved in the conversion-process. The so formed wall precursors pass through the ER and fuse into the intine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01405914
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  • 57
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    Preliminary observations on the formation of the male germ unit in pollen tubes ofCyphomandra betacea sendt. (1988)
    Springer
    Protoplasma 147 (1988), S. 55-63 
    Details
    ISSN: 1615-6102
    Keywords: Generative cell ; Sperm cell ; Treetomato ; Ultrastructure ; Vegetative nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The structure of the generative cell and its association with the vegetative nucleus in the pollen tube ofCyphomandra betacea Sendt. were observed with the electron microscope. The generative cell, bounded by its own plasma membrane and the inner plasma membrane of the vegetative cell, possesses the cytoplasmic extension which lies within the embayments of a vegetative nucleus. The generative cell contains the normal complement of organelles and, especially, microtubules which cluster into several groups adjacent to the plasma membrane, oriented along the longitudinal axis of the cell. In the pollen tube reaching the lower end of the style aftersemivivo pollination, both of the sperm cells are elongated and polyribosomes and microtubules are the outstanding feature in the cytoplasm. The two sperm cells are connected by a common transverse cell wall, while cytoplasmic channels exist in both the periplasm of the two sperm cells and the transverse wall. The leading sperm cell (Svn) is closely associated with the vegetative nucleus. Thus the present study demonstrates the existence of the male germ unit in the pollen tube ofC. betacea. The possible cytoplasmic continuity between the sperm cells and between the gametes and vegetative cell is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01403877
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  • 58
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    Morphology ofEntomophthora muscae protoplasts grownin vitro (1988)
    Springer
    Protoplasma 146 (1988), S. 166-173 
    Details
    ISSN: 1615-6102
    Keywords: Entomophthorales ; Entomophthora muscae ; Ultrastructure ; Cytochemistry ; Protoplast ; in vitro growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Entomophthora muscae (C.) Fres. can be grownin vitro as protoplasts. Light and electron microscopical studies of thein vitro developed protoplasts have demonstrated the absence of an organized wall over the protoplasmic Con A-positive membrane at all stages of growth. The cytological organization is typical of the Entomophthorales with condensed chromatin in the interphase nuclei and small eccentric metaphase spindles. Long strands of endoplasmic reticulum, microubules and vesicles surrounding the plasmalemma may be involved in maintaining the precise shape ofE. muscae protoplast. Starvation of the fungus induces the formation of hyphal bodies after deposition of Con A- and WGA-positive wall material at the plasmalemma surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01405926
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  • 59
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    Electronic Resource
    Effects ofl-propionylcarnitine on electrical and mechanical alterations induced by amphiphilic lipids in isolated guinea pig ventricular muscle (1988)
    Springer
    Heart and vessels 4 (1988), S. 197-206 
    Details
    ISSN: 1615-2573
    Keywords: l-Propionylcarnitine ; Amphiphile ; Action potential ; Ultrastructure ; Guinea pig ventricular muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined the effects ofl-propionyl-carnitine (Prop.C), a short-chain acylcarnitine, on amphiphile (l-lysophosphatidylcholine orl-palmitoylcarnitine)-induced electrophysiological and ultrastructural changes in isolated guinea pig ventricular papillary muscles, under acidic conditions (pH 6.9). Conventional microelectrode, tension-recording, and electron microscope techniques were used. Both amphiphiles, at a concentration of 10−4 M, significantly decreased the resting membrane potential, action potential amplitude, and action potential duration, but increased the developed and resting tension. Such amphiphile-induced electrical changes were not observed in muscles pretreated with the beta-blocker, atenolol, although the mechanical changes remained unaffected. The application of Prop.C (10−2 M), in the continued presence of the amphiphiles caused a return of the action potential duration and the developed tension to the control level. However, the resting potential and action potential amplitude remained unaffected; in fact, the maximum upstroke velocity ( $$\dot V_{max} $$ ) of the action potential tended to decrease further. Pretreatment with Prop.C prevented all the amphiphile-induced electrophysiological and mechanical changes, except for $$\dot V_{max} $$ . Electron microscopic studies revealed that amphiphile-induced ultrastructural changes were prevented, at least in part, in the presence of Prop.C. Thus, Prop.C antagonizes some of deleterious effects of amphiphiles, such as lysophosphatidylcholine and palmitoylcarnitine, upon the electrical and mechanical activities of the ventricular muscle, under acidic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058587
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    Dynamics of the microtubular cytoskeleton in the green algaAphanochaete magna (Chlorophyta). I. Late mitotic stages and the origin and development of the phycoplast (1988)
    Springer
    Protoplasma 142 (1988), S. 176-187 
    Details
    ISSN: 1615-6102
    Keywords: Aphanochaete ; Astral microtubules ; Immunofluorescence ; Phycoplast ; Spindle breakdown ; 3-D reconstruction ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spatial and temporal organization of the microtubular cytoskeleton at the transitional stage of mitosis and cytokinesis has been studied in the chaetophoralean green algaAphanochaete magna using indirect immunofluorescence light microscopy and transmission electron microscopic analysis of serial sections including computer-aided three-dimensional reconstruction. At late mitosis, elaborate asterlike microtubule systems including bundles interconnecting both centriolar regions are present. These systems disappear a the onset of interzonal spindle disintegration. The incipient phycoplast consists of a star-shaped microtubule assemblage projecting from the intact interzonal spindle. It develops strongly at the time of spindle disintegration, later on it becomes compressed by daughter nuclei movement. Cell plate formation is associated with a two-dimensional phycoplast. Phycoplast microtubules remain for a while associated with the completed cross wall but finally they depolymerize. The general occurrence of astral microtubule systems (includingA. magna) is evaluated. The subsequent developmental stages of the phycoplast, formation, maturation and depolymerization, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01290874
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    Ultrastructural aspects of the hyphal tip ofSclerotium rolfsii preserved by freeze substitution (1988)
    Springer
    Protoplasma 146 (1988), S. 143-149 
    Details
    ISSN: 1615-6102
    Keywords: Hyphal tip ; Ultrastructure ; Freeze substitution ; Sclerotium rolfsii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hyphal tip ofSclerotium rolfsii was examined after fixation by freeze substitution. The Spitzenkörper consisted of a dense mass of apical vesicles and microvesicles surrounding a vesicle-free zone. Linear arrangements of microvesicles were occasionally observed within the Spitzenkörper. Abundant microfilaments were seen within the Spitzenkörper region, often in close association with apical vesicles and microvesicles. Microtubules passed through the Spitzenkörper and terminated at the plasmalemma at the extreme hyphal apex. Filasomes were mostly observed within the apical region and were in close proximity to the plasmalemma. Rough ER, mitochondria, microtubules, and vacuoles were abundant in the subapical region and were usually oriented parallel to the long axis of the hypha. Ribosomes were aligned on the outer surfaces of mitochondria. Golgi body equivalents were observed throughout the subapical region and appeared as inflated cisternae of varying shapes and electron opacities. Relationships to other basidiomycetous hyphal tip cells are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01405923
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    Sublethal muscle fibre injuries after high-tension anaerobic exercise (1988)
    Springer
    European journal of applied physiology 57 (1988), S. 360-368 
    Details
    ISSN: 1439-6327
    Keywords: Humans ; Skeletal muscles ; Anaerobic exercise ; Histocytochemistry ; Ultrastructure ; Muscle cell injury
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The vastus lateralis muscles of eleven male elite sprinters (17–28 years) were investigated in order to examine the impact of high tension anaerobic muscular work on muscle fibre fine structure. In an attempt to reproduce the training regimen six subjects ran 20 repetitions of 25 s on a treadmill with 2 min 35 s in between, at a speed corresponding to 86% of their personal best 200 m time. PAS-stained sections of biopsies taken approximately 2 h after training generally indicated glycogen depletion in type 1 and type 2B fibres. At the light microscopic level, no signs of inflammation or fibre rupture were observed. However, at the ultrastructural level, frequent abnormalities of the contractile material and the cytoplasmic organelles were detected. Z-band streaming, autophagic vacuoles and abnormal mitochondria were the most conspicuous observations. Control specimens from sprinters who did not perform the acute exercise routine also displayed structural deviations, although to a lesser degree. It is hypothesized that during sprint training the leg musculature is put under great mechanical and metabolic stress which causes the degenerative response reported here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00635996
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    The effect of low pH and aluminum on the olfactory organ of rainbow trout, Salmo gairdneri (1988)
    Springer
    Environmental biology of fishes 22 (1988), S. 69-77 
    Details
    ISSN: 1573-5133
    Keywords: Acid ; Metals ; Ultrastructure ; Olfaction ; Electrical response ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The effects of acid ((H2SO4) and aluminum AIKSO4 in acidified water on rainbow trout, Salmo gairdneri, olfactory organ were examined using scanning electron microscopy and electrophysiology. Exposure to pH 4.7 resulted in an increase in the number of mucus droplets over parts of the olfactory epithelium, primarily along the ridges of the secondary folds. The addition of aluminum (5.0, 9.5, 20.0 µmol · 1−1) at pH 4.7 resulted in loss of receptor cell cilia, irregularly shaped olfactory knobs, clumped microvilli and swellings on microridge cells. Electrical responses recorded from the olfactory nerve in response to the amino acid L-serine were similar to controls in fish exposed to acidified water. When fish were exposed to acidified water and aluminum the response was depressed. These morphological and electrophysiological changes could be used to indicate metal-induced stress in fish from natural ecosystems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000544
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    Mucus-producing adenopapillary carcinoma of minor salivary gland origin with signet ring cells and intracytoplasmic lumina (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 145-150 
    Details
    ISSN: 1434-4726
    Keywords: Salivary gland tumor ; Adenocarcinoma ; Ultrastructure ; Signet-ring cell ; Intracytoplasmic lumen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A histological and subcellular study of a mucus-producing adenopapillary carcinoma of a minor salivary gland is presented. The tumor was located on the buccal mucosa of a 36-year-old white man. Microscopic examination showed that the tumor was an invasive papillary growth with numerous signet-ring cells and mucous production. When viewed under the electron microscope, the tumor exhibited clusters of cells showing intracellular lumina and finely dispersed chromatin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464016
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    The basement membrane and associated structures in the murine endolymphatic sac (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 266-272 
    Details
    ISSN: 1434-4726
    Keywords: Murine endolymphatic sac ; Basement membrane ; Fluid transport ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the basement membrane of the murine endolymphatic sac was studied under various experimental conditions in labyrinthectomized and ethacrynic acid-treated animals and was compared with normal anatomy. The basement membrane was clearly visualized after staining with ruthenium red or dialyzed iron. The basement membrane of the murine sac consists of two different layers: the lamina rara and the lamina densa. It demarcates the border between the epithelial cells and the subepithelial connective tissue. Our findings suggest that the basement membrane acts as a physical support to the epithelium in the endolymphatic sac. The basement membrane also shows a dynamic capacity to form a new basement membrane, with the result that the lateral intercellular space between contiguous epithelial cells may be integrated with the subepithelial space. This system is believed to act as a macromolecular and bulk water transport system. In the subepithelial space, collagen, reticular and elastic fibrils are found having a close relationship to the basement membrane. The elastic fibres are presumed to play a role in the pressure-regulating mechanism in the endolymphatic sac.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464628
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    Ciliated mucous cells found in the nasal mucosa of a patient with Kartagener's syndrome (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 244 (1988), S. 360-362 
    Details
    ISSN: 1434-4726
    Keywords: Nasal mucosa ; Kartagener's syndrome ; Ciliated mucous cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Transmission electron microscopy revealed the presence of ciliated cells containing many mucous secretory granules in the nasal surface epithelium of a 13-year-old patient suffering from Kartagener's syndrome. In these cells, mucous secretory granules were accumulated in the apical cytoplasm, and the Golgi apparatus was well developed in the supranuclear region. Mucous secretory granules were discharged infrequently through the apical cell membranes by single or compound exocytosis. The cells were considered to be ciliated mucous cells, which have already been reported to be present in the lower respiratory tract but not in the upper respiratory tract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00497465
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    Intermolecular localization of epitopes within an oligomeric protein by immunoelectron microscopy and image processing (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 161-183 
    Details
    ISSN: 0887-3585
    Keywords: hemocyanin ; correspondence analysis ; monoclonal antibodies ; electron microscopy ; images analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Three epitopes have been localized by immunoelectron microscopy on subunits Aa6 of the 4 × 6-meric hemocyanin of the scorpion Androctonus australis. Soluble immunocomplexes composed of monoclonal antibodies and of native hemocyanin were purified, negatively stained with uranyle acetate by the single-layer technique, and examined under the electron microscope (EM). The molecule images were digitized, aligned, and submitted to correspondence analysis according to the method of Van Heel and Frank (Ultramicroscopy 6: 187-194, 1981). A high-precision localization of the attachment point of the Fab arm to the antigen was achieved through a careful analysis of the average images. This method easily allowed the discrimination of epitopes located in different domains (Mr 20 kDa) of the same subunit. Nonoverlapping epitopes located in the same structural domain of subunit Aa6 could be distinguished by the stain exclusion patterns of their Fab arms. The method is general and may be used for epitope mapping in any antigen producing definite EM views.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340030305
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    Crystallization and preliminary X-ray diffraction study of a protein with a high potential rubredoxin center and a hemerythrin-type Fe center (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 184-186 
    Details
    ISSN: 0887-3585
    Keywords: new Fe-protein ; rubredoxin ; hemerythrin ; crystals ; X-ray diffraction ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A newly discovered iron-containing protein, isolated from the bacterium Desulfovibrio vulgaris (Hildenborough, NCIB 8303), has been crystallized. The molecule appears to be a dimer of mass 44kDa. This protein has iron centers with spectroscopic similarities to those in rubredoxins and in hemerythrins.The X-ray diffraction shows symmetry consistent with space group I222 or I212121. Cell parameters are a = 49.2 Å, b = 81.3 Å, c= 100.1 Å, and α, β, γ = 90°. X-ray diffraction data have been collected to 3.0 Å, and a search for useful heavy atom derivatives is in progress for the analysis of the crystal structure of this Fe-protein.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340030306
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    Lecithin: Cholesterol acyltransferase activation by synthetic amphipathic peptides (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 187-198 
    Details
    ISSN: 0887-3585
    Keywords: amphipathic peptide ; liposomes ; peptide ; serum apolipoproteins ; synthetic ; LCAT ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The amphipathic helical theory of Segrest and colleagues (FEBS Lett.: 38: 247-253, 1974) proposes that the lipid-binding segments of serum apolipoproteins are in an alpha helical conformation. Furthermore the helices have a hydrophobic face and a hydrophilic face with a specific distribution of positively and negatively charged residues. The importance of the pattern of the charged residues in the lipid binding and lecithin:cholesterol acyltransferase (LCAT) activation by the segments is still debated. We designed a 30-residue peptide, GALA, which in the alpha helical conformation hs a hydrophilic face composed of glutamic acid residues (Sabbarao et al.: Biochemistry 26: 2964-2972, 1987). GALA behaves like the serum apolipoproteins in its interaction with dimyristoylphospatidylcholine (DMPC) at neutral pH; the amino terminal tryptophan of GALA undergoes a blue shift in its fluorescence emission spectrum, and the circular dichroism (CD) spectrum indicates that GALA acquires alpha helical structure in the presence of DMPC. A DMPC-GALA:19/1 (molar ratio) complex can be isolated by gel-permeation chromatography. This complex has a discoidal structure with the approximate dimensions of 44-Å diameter. GALA edge thickness and a 170- to 350-Å diameter. GALA activates LCAT with DMPC but not with unsaturated phospholipids as the substrate. The apparent partition coefficient of GALA into DMPC vesicles is 100-fold larger than into egg phosphatidlylcholine vesicles. The interaction of GALA with unsaturated lipids at neutral pH is so weak that no detectable change in the spectroscopic properties of GALA or the structure of the liposomes can be detected under the conditions used here. The sequence of GALA differs from previously studied model Apo A1 peptides by the absence of positively charged residues on the hydrophilic face. This indicates that positive charges in Apo A1-like peptides are not required in order to form discoidal structures with saturated phospholipids or to activate LCAT with such lipid substrates.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340030307
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    In memorium: Emil Thomas Kaiser, 1938-1988 (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. i 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040102
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  • 71
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    Photochemical crosslinking of bacteriophage T4 single-stranded DNA-binding protein (gp32) to oligo-p(dT)8: Identification of phenylalanine-183 as the site of crosslinking (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 1-6 
    Details
    ISSN: 0887-3585
    Keywords: single-standard DNA-binding protein ; protein-nucleic acid interactions ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Using ultraviolet light, both the 33,000-dalton single-standard DNA-binding protein from T4 bacteriophage (gp32)as well as a 25,000-dalton limited trypsin cleavage product of gp32 (core gp32*) that retains high affinity for single-stranded DNA can be crosslinked to an oligodeoxynucleotide, p(dT)8. After photolysis, a single tryptic peptide crosslinked to p(dT)8 was isolated by anion-exchange high-performance liquid chromatography. Gas-phase sequencing of this modified peptide gave the following sequence: Gln-Val-Ser-Gly-(X)-Ser-Asn-Tyr-Asp-Glu-Ser-Lys, which corresponds to residues 179-190 in gp32. Based on the absence of the expected phenylthiohydantoin derivative of phenylalanine 183 at cycle 5 (X) we infer that crosslinking has occurred at this position and that phenylalanine 183 is at the interface of the gp32:P(dT)8 complex in an orientation that allows covalent bond formation with the thymine radical produced by ultraviolet irradiation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040103
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    Structure-function relationships in 3-phosphoglycerate kinase: Role of the carboxy-terminal peptide (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 56-62 
    Details
    ISSN: 0887-3585
    Keywords: Protein engineering ; mutagenesis ; enzyme catalysis ; conformational changes ; domain movement ; hinge bending ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Yeast 3-phosphoglycerate kinase (PGK) is a monomeric enzyme (Mr ∼ 45,000) composed of two globular domains. Each domain corresponds approximately to the amino- and carboxyterminal halves of the polypeptide chain. The carboxy-terminal end extends over the interdomain “hinge” region and packs against the amino-terminal domain. It has been proposed that domain movement, resulting in closure of the active site left, is essential for the catalytic of PGK. Large-scale conformational changes have also been postulated to explain activation of the enzyme by sulfate ions. Using site-specific mutagenesis, we have removed a 15-amino-acid carboxy-terminal fragment, in order to probe its role in the substrate- and sulfate-induced conformational changes. The truncated enzyme exhibited approximately 1% of the activity of native PGK and lost the ability to undergo sulfateinduced activation. The Km for ATP was essentially unchanged (Km = 0.23mM), whereas the Km value for 3-phosphoglycerate was increased about eightfold (Km = 3.85 mM and 0.50 mM, respectively). These results suggest that the carboxy-terminal segment is important for the mechanism of substrate- and specific-induced conformational transitions. CD spectra and sedimentation velocity measurements indicate that the carboxy-terminal peptide is essential for structural integrity of PGK. The increased susceptibility of the truncated enzyme to thermal inactivation implies that the carboxy-terminal peptide also contributes to the stability of PGK.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040108
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    Model of a complex between the tetrahemic cytochrome c3 and the ferredoxin I from Desulfovibrio desulfuricans (Norway strain) (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 63-70 
    Details
    ISSN: 0887-3585
    Keywords: molecular graphics ; protein complex ; electron transfer ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A three-dimensional model of an electron-transfer complex between the tetrahemic cytochrome c3 and the ferredoxin I from the sulfatereducing bacterium Desulfovibrio desulfuricans (Norway strain) has been generated through computer graphics methods. The model is based on the known X-ray structure of the cytochrome and on a model of the ferredoxin that has been derived through computer graphics modeling and energy minimization methods, from the X-ray structure of the homologous ferredoxin from Peptococcus aerogenes. Four possible models of interaction between the two molecules were examined by bringing in close proximity each of the four hemes and the redox center (4Fe-4S) of the ferredoxin and by optimizing the ion pairs interactions. One of these models shows by far the “best” structure in terms of charges, interactions, and complementary f the topology of the contact surfaces. In this complex, the distance between the iron atoms of the ferredoxin redox center and the hemic iron atom is 11.8 Å, which compares well with those found between redox centers in other complexes. The contact surface area between the two molecules is 170 Å2.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040109
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988) 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040201
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    Crystallization and preliminary investigation of single crystals of deoxyuidine triphosphate nucleotidohydrolase from Escherichia coli (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 71-75 
    Details
    ISSN: 0887-3585
    Keywords: dUTPase ; nucleotide binding enzyme ; X-ray crystallography ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Deoxyuridine triphosphate nucleotidohydrolase (dUTPase), an enzyme in the nucleotide metabolism that is a pyrophosphatase hydrolyzing dUTP, has been crystallized. The crystals belong to the trigonal space group R3 and diffract beyond 2 Å. The native dUTPase crystals and a mercury derivative are stable in the X-ray beam and are suitable for a high resolution X-ray structure analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040110
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    Crystallographic studies of inhibitor binding sites in human carbonic anhydrase II: A pentacoordinated binding of the SCN- ion to the zinc at high pH (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 283-293 
    Details
    ISSN: 0887-3585
    Keywords: crystallography ; structure ; refinement ; sulfonamide ; thiocyanate ; mercury ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The binding of four inhibitors - mercuric ion, 3-acetoxymercuri-4-aminobenzenesulfonamide (AMS), acetazolamide (Diamox), and thiocyanate ion - to human carbonic anhydrase II (HCA II) has been studied with X-ray crystallography.The binding of mercury to HCA II at pH 7.0 has been investigated at 3.1 Å resolution. Mercuric ions are observed at both nitrogens in the His-64 ring. One of these sites is pointing toward the zinc ion. The only other binding site for mercury is at Cys-206.The binding of the two sulfonamide inhibitors AMS and Diamox, has been reinvestigated at 2.0 and 3.0 Å, respectively. Only the nitrogen of the sulfonamide group binds to the zinc ion replacing the hydroxyl ion. The sulfonamide oxygen closet to the zinc ion is 3.1 Å away. Thus the tetrahedral geometry of the zinc is retained, refuting earlier models of a pentacoordinated zinc.The structure of the thiocyanate complex has been investigated at pH 8.5 and the structure has been refined at 1.9 Å resolution using the least-squares refinement program PROLSQ. The crystallographic R factor is 17.6%. The zinc ion is pentacoordinated with the anion as well as a water molecule bound in addition to the three histidine residues. The nitrogen atom of the SCN- ion is 1.9 Å from the zinc ion but shifted 1.3 Å with respect to the hydroxyl ion in the native structure and at van der Waals' distance from the Oγl atom of Thr-199. This is due to the inability of the Oγl atom of Thr-199 to serve as a hydrogen bond donor, thus repelling the nonprotonated nitrogen. The SCN- molecule reaches into the deep end of the active site cavity where the sulfur atom has displaced the so-called “deep” water molecule of the native enzyme. The zinc-bound water molecule is 2.2 Å from the zinc ion and 2.4 Å from the SCN- nitrogen. In addition, this water is hydrogen bonded to the Oγl atom of Thr-199 and to another water molecule.We have observed that solvent and inhibitor molecules have three possible binding sites on the zinc ion and their significance for the catalysis and inhibition of HCA II will be discussed. All available crystallographic data are consistent with a proposed catalytic mechanism in which both the OH moiety and one oxygen of the substrate HCO3- ion are ligated to the zinc ion.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040407
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    Further experimental studies of the disulfide folding transition of ribonuclease A (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 251-261 
    Details
    ISSN: 0887-3585
    Keywords: protein folding kinetics ; disulfide bonds ; thiol-disulfide exchange ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Two very different mechanisms of folding have been proposed from experimental studies of disulfide formation in reduced ribonuclease A. (1) A pathway in which the rate-limiting step separates fully folded protein from all other disulfide intermediates and occurs solely in three-disulfide intermediates. (2) A multiple pathway mechanism with different rate-limiting steps for each pathway. The various rate-limiting steps involve disulfide breakage, formation, and rearrangement in intermediates with one, two, three, and four protein disulfides. To distinguish between these two mechanisms, we have carried out further studies of both unfolding and refolding.Refolding of reduced ribonuclease A requires three-disulfide intermediates to accumulate; negligible refolding occurs when only the nearly random one- and two-disulfide intermediate species are populated. Therefore, no rate-limiting steps of the type postulated in mechanism (2) occur in intermediates with one and two protein disulfides. Unfolding and disulfide reduction is an all-or-none process; no disulfide intermediates accumulate to detectable to detectable levels or precede the rate-limiting step. Mechanism (2) requires that such intermediates precede the rate-limiting step and accumulate to substantial levels.The different proposal were shown not to result from the use of different solution conditions or disulfide reagents; the two sets of data are not inconsistent. Instead, the inappropriate mechanism (2) resulted from an incorrect kinetic analysis and misinterpretation of the kinetics of disulfide formation are breakage.
    Additional Material: 6 Ill.
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988) 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340030201
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    Conformational characteristics of the complete cequence of group A streptococcal M6 protein (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 60-69 
    Details
    ISSN: 0887-3585
    Keywords: coiled-coli ; alpha-helix ; antiphagocytic ; heptad ; antigenic variation ; sequence repeats ; cell wall protein ; intermediate filaments ; myosin ; tropomyosin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: M protein is considered a virulence determinant on the streptococcal cell wall by virtue of its ability to allow the organism to resist attack by human neutrophils. The complete DNA sequence of the M6 gene from streptococcal strain D471 has allowed, for the first time, the study of the structural characteristics of the amino acid sequence of an entire M protein molecule. Predictive secondary structural analysis revealed that the majority of this fibrillar molecule exhibits strong alpha-helical potential and that, except for the ends, nonpolar residues in the central region of the molecule exhibit the 7-residue periodicity typical for coiled-coil proteins. Differences in this heptad pattern of nonpolar residues allow this central rod region to be divided into three subdomains which correlate essentially with the repeat regions A, B, and C/D in the M6 protein sequence. Alignment of the N-terminal half of the M6 sequence with PepM5, the N-terminal half of the M5 protein, revealed that 42% of the amino acids were identical. The majority of the identities were “core” nonpolar residues of the heptad periodicity which are necessary for the maintenance of the coiled coil. Thus, conservation of structure in a sequence-variable region of these molecules may be biologically significant. Results suggest that serologically different M proteins may be built according to a basic scheme: an extended central coiled-coil rod domain (which may vary in size among strains) flanked by functional end domains.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340030106
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    Identification of structural motifs from protein coordinate data: Secondary structure and first-level supersecondary structure*A FORTRAN version of the program DEFINE_STRUCTURE, which defines the secondary structure and characterizes the first level of supersecondary structure, is available from the authors (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 71-84 
    Details
    ISSN: 0887-3585
    Keywords: Cα coordinates ; distance matrix ; difference distance matrix ; helix axes, strand axes ; interaxial angles ; turns ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A computer program is described that produces a description of the secondary structure and supersecondary structure of a polypeptide chain using the list of alpha carbon coordinates as input. Restricting the term “secondary structure” to the conformation of contiguous segments of the chain, the program determines the initial and final residues in helices, extended strands, sharp turns, and omega loops. This is accomplished through the use of difference distance matrices. The distances in idealized models of the segments are compared with the actual structure, and the differences are evaluated for agreement within preset limits. The program assigns 90-95% of the residues in most proteins to at least one type of secondary elementIn a second step the now-defined helices and strands are idealized as straight line segments, and the axial directions and locations are compiled from the input Cα coordinate list. These data are used to check for moderate curvature in strands and helices, and the secondary structure list is corrected where necessary. The geometric relations between these line segments are then calculated and output as the first level of supersecondary structure. A maximum of six parameters are required for a complete description of the relations between each pair. Frequently a less complete description will suffice, for example just the interaxial separation and angle. Both the secondary structure and one aspect of the supersecondary structure can be displayed in a character matrix analogous to the distance matrix format. This allows a quite accurate two-dimensional display of the three-dimensional structure, and several examples are presentedA procedure for searching for arbitrary substructures in proteins using distance matrices is also described. A search for the DNA binding helix-turnhelix motif in the Protein Data Bank serves as an exampleA further abstraction of the above data can be made in the form of a metamatrix where each diagonal element represents an entire secondary segment rather than a single atom, and the off-diagonal elements contain all the parameters describing their interrelations. Such matrices can be used in a straightforward search for higher levels of supersecondary structure or used in toto as a representation of the entire tertiary structure of the polypeptide chain.
    Additional Material: 5 Ill.
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    Pattern descriptors and the unidentified reading frame 6 human mtDNA dinucleotide-binding site (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 97-101 
    Details
    ISSN: 0887-3585
    Keywords: URF ; nucleotide-binding sites ; pattern descriptor ; computer search ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In an effort to identify the structural elements essential to a given protein function a new pattern-directed inference system has been developed. It has been employed to identify a potential dinucleotide-binding domain within the human mitochondrial unidentified reading frame 6 product, thereby supporting an earlier study that this gene may encode a NADH dehydrogenase subunit.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340030204
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    Lysine/fibrin binding sites of kringles modeled after the structure of kringle 1 of prothrombin (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 85-96 
    Details
    ISSN: 0887-3585
    Keywords: molecular modeling ; energy minimization ; lysine/fibrin binding ; kringle structures ; plasminogen ; tissue plasminogen activator ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The Lys binding site of kringle 1 and 4 (K1 and K4) of plasminogen (PG) has been modeled on the basis of the three-dimensional structure of kringle 1 of prothrombin and 300- and 600-MHz proton nuclear magnetic resonance observations. These structures were then compared to the corresponding regions of modeled kringle 1 and 2 of tissue plasminogen activator (PA). The coordinates of the modeled structures have been refined by energy minimization in the presence and absence of ∊-aminocaproic acid ligand in order basically to remove unacceptable van der Waals contacts. The binding site is characterized by an apparent dipolar surface, the polar parts of which are separated by a hydrophobic region of highly conserved aromatic residues. Zwitterionic ligands such as Lys and ∊-aminocaproic acid form ion pair interactions with Asp55 and Asp57 located on the dipolar surface; the latter are also conserved in all the Lys binding kringles. The cationic center of the dipolar surface is Arg71, in the case of PGK4, and is composed of Arg34 and Arg71 in PGK1. The doubly charged anionic/cationic interaction centers of the latter might account for the larger binding constants of PGK1 for like-ligands but the modeling suggests that PGK4 might be kinetically faster in binding bulkier ligands. The binding site region of PAK2, which also binds Lys, resembles those of PGK1 and PGK4. Since PAK2 lacks both cationic center Arg residues, ligand carboxylate binding appears to be accomplished though an imidazolium ion of His64, which is located just below the outer surface of the kringle.
    Additional Material: 6 Ill.
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  • 83
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    Site-directed mutations altering methyl-accepting residues of a sensory transducer protein (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 102-112 
    Details
    ISSN: 0887-3585
    Keywords: bacterial chemotaxis ; sensory adaptation ; protein modification ; membrane protein ; receptor protein ; transmembrane signalling ; Escherichia coli ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The Trg protein is one of a family of transducer proteins that mediate chemotactic response in Escherichia coli. Transducers are methylaccepting proteins that gain or lose methyl esters on specific glutamyl residues during sensory adaptation. In this study, the significance of multiple sites of methylation on transducer proteins was addressed by using oligonucleotide-directed, site-specific mutagenesis to substitute an alanyl residue at each of the five methyl-accepting sites in Trg. The resulting collection of five mutations, each inactivating a single site, was analyzed for effects on covalent modification at the remaining sites on Trg and for the ability of the altered proteins to mediate sensory adaptation. Most of the alanyl substitutions had substantial biochemical effects, enhancing or reducing methyl-accepting activity of other sites, including one case of activation of a site not methylated in wild-type protein. Analysis of the altered proteins provided explanations for many features of the complex pattern of electrophoretic forms exhibited by Trg. The mutant proteins were less efficient than normal Trg in mediating adaptation. Correlation of biochemical and behavioral data indicated that reduction in the number of methyl-accepting sites on the transducer lengthened the time required to reach an adapted state.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340030205
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    Human myeloperoxidase and thyroid peroxidase, two enzymes with separate and distinct physiological functions, are evolutionarily related members of the same gene family (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 113-120 
    Details
    ISSN: 0887-3585
    Keywords: evolution ; proximal histidine ; distal histidine ; heme enzyme ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Human myeloperoxidase and human thyroid peroxidase nucleotide and amino acid sequences were compared. The global similarities of the nucleotide and amino acid sequences are 46% and 44%, respectively. These similarities are most evident within the coding sequence, especially that encoding the myeloperoxidase functional subunits. These results clearly indicate that myeloperoxidase and thyroid peroxidase are members of the same gene family and diverged from a common ancestral gene. The residues at 416 in myeloperoxidase and 407 in thyroid peroxidase were estimated as possible candidates for the proximal histidine residues that link to the iron centers of the enzymes. The primary structures around these histidine residues were compared with those of other known peroxidases. The similarity in this region between the two animal peroxidases (amino acid 396-418 in thyroid peroxidase and 405-427 in myeloperoxidase) is 74%; however, those between the animal peroxidases and other yeast and plant peroxidases are not significantly high, although several conserved features have been observed. The possible location of the distal histidine residues in myeloperoxidase and thyroid peroxidase amino acid sequences are also discussed.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340030206
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  • 85
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    Peptide synthesis catalyzed by polyethylene glycol-modified chymotrypsin in organic solvents (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 130-137 
    Details
    ISSN: 0887-3585
    Keywords: peptide synthesis ; chymotrypsin specificity ; polyethylene glycol ; nonaqueous solvents ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Chymotrypsin modified with polyethylene glycol was successfully used for peptide synthesis in organic solvents. The benzene-soluble modified enzyme readily catalyzed both aminolysis of N-benzoyl-L-tyrosine p-nitroanilide and synthesis of N-benzoyl-L-tyrosine butylamide in the presence of trace amounts of water. A quantitative reaction was obtained when either hydrophobic or bulky amides of L- as well as D-amino acids were used as acceptor nucleophiles, while almost no reaction occurred with free amino acids or ester derivativesThe acceptor nucleophile specificity of modified chymotrypsin as a catalyst in the formation of both amide and peptide bonds in organic solvents was quite comparable to that in aqueous solution as well as to that of the leaving group in hydrolysis reactions. By contrast, the substrate specificity of modified chymotrypsin in organic solvents was different from that in water since arginine and lysine esters were found to be as effective as aromatic amino acids to form the acyl-enzyme with subsequent synthesis of a peptide bond.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340030208
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    Vibrational spectroscopy of bacteriorhodopsin mutants: I. Tyrosine-185 protonates and deprotonantes during the photocycle (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 219-229 
    Details
    ISSN: 0887-3585
    Keywords: proton transport ; energy transduction ; purple membrane ; proton wire ; Schiff base counter-ion ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The techniques of FTIR difference spectroscopy and site-directed mutagenesis have been combined to investigate the role of individual tyrosine side chains in the proton-pumping mechanism of bacteriorhodopsin (bR). For each of the 11 possible bR mutants containing a single Tyr→Phe substitution, difference spectra have been obtained for the bR→K and bR→M photoreactions. Only the Tyr-185→Phe mutation results in the disappearance of a set of bands that were previously shown to be due to protonation of a tryosinate during the br→K photoreaction [Rothschild et al.: Proceedings of the National Academy of Sciences of the United states of America 83:347, (1986)]. The Tyr-185→Phe mutation also eliminates a set of bands in the bR→M difference spectrum associated with deprotonation of a Tyr; most of these bands (e.g., positive 1272-cm-1 peak) are completely unaffected by the other ten Tyr→Phe mutations. Thus, tyrosinate-185 gains a proton during the bR→K reaction and loses it again when M is formed. Our FTIR spectra also provide evidence that Tyr-185 interacts with the protonated Schiff base linkage of the retinal chromophore, since the negative C=NH+ stretch band shifts from 1640 cm-1 in the wild type to 1636 cm-1 in the Tyr-185→Phe mutant. A model that is consistent with these results is that Tyr-185 is normally ionized and serves as a counter-ion to the protonated Schiff base. The primary photoisomerization of the chromophore translocates the Schiff base away from Tyr-185, which raises the pKa of the latter group and results in its protonation.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340030403
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    Structural comparison of the prokaryotic ribosomal proteins L7/L12 and L30 (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 3 (1988), S. 243-251 
    Details
    ISSN: 0887-3585
    Keywords: protein evolution ; structural homology ; ribosome structure ; x-ray crystallography ; common motif ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The structure of two prokaryotic ribosomal proteins, the carboxyterminal half of L7/L12 from Escherichia coli (L12CTF) and 1.30 from Bacilus Stearothermophilus display a remarkably similar fold in which alpaha-helices pack onto one side of an antiparallel, three-stranded, beta-pleated sheet. A detailed comparison of the structures by least-squares methods reveals that more than two-thirds of the alpha carbons can be superimposed with a root mean square distance of 2.33 Å. The principal difference is an extra alpha-helix in L12 CTF. The sequences of the proteins display a distinct conservation in regions which are crucial to the common fold, in particular the hydrophobic core. It is proposed that the similarity is a result of divergent evolution.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340030405
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  • 88
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    Crystallographic structure analysis of lamprey hemoglobin from anomalous dispersion of synchrotron radiation (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 77-88 
    Details
    ISSN: 0887-3585
    Keywords: protein structure ; diffraction ; anomalous scattering ; x-ray crystallography ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The molecular structure of lamprey hemoglobin was previously determined and refined by conventional crystallographic analysis. In this study, the structural analysis has been repeated in the course of developing the method of multiwavelength anomalous diffraction (MAD) for phase determination. New experimental and analytical procedures that were devised to perform this determination should have general applicability. These include an experimental design to optimize signal strength and reduce systematic errors, experimental evaluation of anomalous scattering factors, and a least-squares procedure for analyzing the MAD data. MAD phases for the structure at 3Å resolution are as accurate overall as the multiple isomorphous replacement (MIR) phases determined previously.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340040202
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    Conformation of alamethicin in phospholipid vesicles: Implications for insertion models (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 89-98 
    Details
    ISSN: 0887-3585
    Keywords: membrane proteins ; channels ; circular dichroism spectroscopy ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The secondary structure of alamethicin, a membrane channel-forming polypeptide, has been examined by circular dichroism spectroscopy to determine the relationship of its conformation in organic solution to its conformation in a membrane-bound state. The spectrum of alamethicin in small unilamellar dimyristoyl phosphatidylcholine vesicles is significantly different from its spectrum in 10% methanol/acetonitrile, the solvent from which it was crystallized (Fox and Richards: Nature 300:325-330, 1982), as well as its spectrum in methanol, the solvent in which NMR studies have been done (Banerjee and Chan: Biochemistry 22:3709-3713, 1983). This suggests that structural models based on studies of the molecule in organic solvents may not be entirely appropriate for the membrane-bound state. To distinguish between different models for channel formation and insertion, two different methods were used to associate the alamethicin with vesicles; in addition, the effect of oligomerization on the conformation of the membrane-bound state was investigated. These studies are consistent with a modified insertion model in which alamethicin monomers, dimers, or trimers associate with the bilayer and then spontaneously oligomerize to form a prechannel with a higher helix content. This aggregate could then “open” upon application of an appropriate gating transmembrane potential.
    Additional Material: 4 Ill.
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  • 90
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    Internal motion of a tryptophan residue in Streptomyces subtilisin inhibitor: Deuterium nuclear magnetic resonance in solution (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 131-136 
    Details
    ISSN: 0887-3585
    Keywords: 2H NMR ; selective deuteration ; tryptophan internal motion ; SSI-subtilisin complex ; protein conformational equilibrium ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Deuterium NMR spectroscopy was used to study internal motions of a deuterium-labeled single tryptophan (Trp) residue (per subunit) of Streptomyces subtilisin inhibitor (SSI) in solution. The free inhibitor with the five ring protons of the Trp replaced with deuterons showed a narrow resonance component (56 Hz) of about one-quarter of the total intensity, in addition to the broad resonance component (about 600 Hz) at 25°C, showing that it exits in an equilibrium mixture of two conformers, in one of which the typtophan side chain is highly mobile. In analogy to the two structures of SSI found in the crystal, these two conformers were attributed to the one in which the contact between the α-lobe and the beta;-lobe of the subunit is tight and the other in which the same contact is loose. When SSI forms a complex with subtilisin BPN′, the broad component becomes invisibly broad, but the narrow component increases with even further narrowing, suggesting that the binding to the enzyme favors the “loose” conformer over the “tight” conformer.
    Additional Material: 4 Ill.
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    Surface interactions of γ-crystallins in the crystal medium in relation to their association in the eye lens (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 137-147 
    Details
    ISSN: 0887-3585
    Keywords: eye lens proteins ; protein association ; crystal packing ; surface area ; homologous proteins ; point mutations ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A comparative study of intermolecular interactions in crystals of two homologous low molecular weight proteins, γ-II and γ-IIIb crystallins, from calf eye lens was carried out. Crystal packings for these proteins are very different: intermolecular contact areas compose about 33% of the total accessible surface area of γ-II as compared with 13% in γ-III. Two key residues seem to be mainly responsible for the differences in protein association in the crystal medium. These are Ser 103 and Leu 155 in γ-II, which are replaced by Met 103 and His 155 in γ-IIIb. A similar substitution of these residues is observed in different gene products of γ-crystallins from a number of vertebrates. This is consistent with the existence of a genetically controlled mechanism for determining intermolecular association of γ-crystallins in the native medium of the lens.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/prot.340040207
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    Polar hydrogen positions in proteins: Empirical energy placement and neutron diffraction comparison (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 148-156 
    Details
    ISSN: 0887-3585
    Keywords: Protein structure ; empirical energy ; energy minimization ; molecular dynamics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A method for the prediction of hydrogen positions in proteins is presented. The method is based on the knowledge of the heavy atom positions obtained, for instance, from X-ray crystallography. It employs an energy minimization limited to the environment of the hydrogen atoms bound to a common heavy atom or to a single water molecule. The method is not restricted to proteins and can be applied without modification to nonpolar hydrogens and to nucleic acids. The method has been applied to the neutron diffraction structures of trypsin ribonuclease A, and bovine pancreatic trypsin inhibitor. A comparison of the constructed and the observed hydrogen positions shows few deviations except in situations in which several energetically similar conformations are possible. Analysis of the potential energy of rotation of Lys amino and Ser, Thr, Tyr hydroxyl groups reveals that the conformations of lowest intrinsic torsion energies are statistically favored in both the crystal and the constructed structures.
    Additional Material: 3 Ill.
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988) 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040301
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    X-ray and model-building studies on the specificity of the active site of proteinase K (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 157-164 
    Details
    ISSN: 0887-3585
    Keywords: synthetic inhibitors ; serine proteinase crystallography ; active site geometry ; computer graphics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Proteinase K, the extracellular serine endopeptidase (E.C. 3.4.21.14) from the fungus Tritirachium album limber, is homologous to the bacterial subtilisin proteases. The binding geometry of the synthetic inhibitor carbobenzoxy-Ala-Phechloromethyl Ketone to the active site of proteinase K was the first determined from a Fourier synthesis based on synchrotron X-ray diffraction data between 1.8 Å and 5.0 Å resolution. The protein inhibitor complexes was refined by restrained least-squares minimization with the data between 10.0 and 1.8 Å. The final R factor was 19.1% and the model contained 2,018 protein atoms, 28 inhibitors atoms, 125 water molecules, and two Ca2+ ions. The peptides portion of the inhibitor is bound to the active center of proteinase K by means of a three-stranded antiparallel pleated sheet, with the side chain of the phenylalanine located in the P1 site. Model building studies, with lysine replacing phenylalanine in the inhibitor, explain the relatively unspecific catalytic activity of the enzyme.
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    URL: http://dx.doi.org/10.1002/prot.340040302
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    Structural analysis of the 2.8 Å model of xylose isomerase from Actinoplanes missouriensis (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 165-172 
    Details
    ISSN: 0887-3585
    Keywords: α/β barrels ; crystal structure ; glucose isomerase ; xylose isomerase ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The structure of Xylose isomerase (X.I.) from Actinoplanes missouriensis has been solved to 2.8 Angstroms resolution. Phases were determined from a single Eu3+ derivative and from the noncrystallographic 22 symmetry of the tetrameric molecule. An atomic model was built and subjected to restrained crystallographic refinement. The resulting model is shown to be closely similar to the recently reported X.I.'s structures from three other bacterial sources. Each monomer is found to be composed of an eight-stranded α/β “T.I.M.” barrel forming an N-terminal domain of 328 residues followed by a large loop of 66 residues embracing an adjacent subunit. Analysis of intersubunit packing shows that the X.I. tetramer is an assembly of two tight dimers. The β barrel fits a simple hyperboloid model as other T.I.M. barrels do. The active site, identified as the binding site for the inhibitor xylitol, is located at the carboxyl end of the beta strands in the barrel next to a pair binding site for Eu3+ ions, which are assumed to the sites for the divalent ions involved in catalysis. Active sites in the tetramer are oriented towards the interface between dimmers. It is suggested that subunit interfaces might stabilize the active site region and this might explain the oligomeric nature of the other α/β barrel enzymes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040303
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    Formation of heterodimers between wild type and mutant trp aporepressor polypeptides of Escherichia coli (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 173-181 
    Details
    ISSN: 0887-3585
    Keywords: DNA binding protein ; ligand binding ; equilibrium dialysis ; dimer ; stability ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Availability of the three-dimensional structure of the trp repressor of Escherichia coli and a large group of repressor mutants has permitted the identification and analysis of mutants with substitutions of the amino acid residues that from the tryptophan binding pocket. Mutant aporepressors selected for study were overproduced using a multicopy expression plasmid. Equilibrium dialysis with 14C-tryptophan and purified mutant and wild type aporepressors was employed to determine tryptophan binding constants. The results obtained indicate that replacement of theronine 44 by methionine (TM44) or arginine 84 by histidine (RH84) lowers the affinity for tryptophan approximately two-and four-fold, respectively. Replacement of ariginine 54 by histidine (RH84) or glycine 85 by ariginine (GR85) results in complete loss of tryptophan binding activity. Purified mutant and wild type aporepressors were used in vitro heterodimer studies. The trp repressor of E. coli functions as a stable dimer. A large number of trp repressor mutants prduces defective repressors that are transdominant to the wild type repressor in vivo. The transdominance presumably results from the formation of inactive or slightly active heterodimers between the mutant and wild type polypeptide subunits. An in vitro assay was developed to detect and measure heterodimer formation. Heterodimer formation was thermally induced, and heterodimers were separated on nondenaturing polyacrylamide gels. Aporepressors readily formed heterodimer formation upon treatment at 65°C for 3 minutes. Heterodimer formation was significantly retarded by the presence of the corepressor, L-tryptophan. Indole-3-propionic acid, 5-methyl tryptophan, and other analogs of tryptophan, as well as indole, also inhibited heterodimer formation. These results indicate that the presence of the indole moiety in the corepressor binding pocket increases the stability of the dimer.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040304
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  • 97
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    Interaction of peptide boronic acids with elastase: Circular dichroism studies (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 205-210 
    Details
    ISSN: 0887-3585
    Keywords: slow-binding inhibition ; transition-state analog ; conformational change ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Boronic acid derivatives of good peptide substrate of the serine proteases cause slow-binding inhibition, manifested as biphasic binding (Kettner and Shenvi: J. Biol. Chem. 259:15106-15114, 1984). These inhibitors are thought to act as reaction-intermediate analogs. Three peptides Boronic acids - Ac-Pro-boro-Val-OH, DNS-Ala-Pro-boro-Val-OH, and Ac-Ala-Ala-Pro-boro-Val-OH - were chosen for farultraviolet circular dichroism (CD) studies in order to determine whether the second phase involves a conformational change of pancreatic elastase. The dipeptide is a simple competitive inhibitors (Ki = 0.27 μM) and the latter are slow-binding inhibitors (Ki = 16.4 and 0.25 nM, respectively). Spectral deconvolution and correction for the formation of antiparallel β-sheet by the peptide inhibitors itself indicate that there is no significant change in the secondary structure of the enzyme in the either the initial or final inhibitors complex. A kinetic experiment confirmed that the slow-binding step was not associated with a CD spectral change, and that therefore a protein conformational change was not responsible for the sow binding.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040307
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  • 98
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988) 
    Details
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040401
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  • 99
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    Diffusion-collision model for the folding kinetics of myoglobin (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 211-227 
    Details
    ISSN: 0887-3585
    Keywords: protein-folding ; multiple pathways ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The diffusion-collision model has been used to analyze the folding kinetics of myoglobins. The microdomains, which are the basic units that coalesce during the folding, are identified with the helices and the stabilizing contacts between helices are determined form the native structure. Both association and disassociation reactions are included and a range of stabilization parameters is investigated to determine the variations in overall rate and the relative contributions made by the different intermediates during the folding process. In a comparison of folding to the native state and to the midpoint of the folding transitions. (i.e., 50% native protein at the completion of the reaction) significant differences in the contributing intermediates are found.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040308
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  • 100
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    Test of circular dichroism (CD) methods for crambin and CD-assisted secondary structure prediction of its homologous toxins (1988)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 4 (1988), S. 262-273 
    Details
    ISSN: 0887-3585
    Keywords: hierarchical assignment ; cereal grain ; mistletoe ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Methods that analyze protein circular dichroism (CD) spectra for fractions of secondary structure are evaluated for the plant protein crambin, which has a known high-resolution crystal structure. In addition, a two-step secondary structure prediction scheme is presented and used for the toxins homologous to crambin, shown by others to have secondary structures similar to crambin.The test of CD spectral analysis methods with the protein crambin employed two computer programs and several CD basis sets. Crambin's crystal structure, known to 0.945 Å resolution (Hendrickson, W.A., Teeter, M.M. Nature 290:107-113, 1981), allows accurate evaluation of results. Analysis with the protein spectra basis sets (Provencher, S. W., Glöckner, J. Biochemistry 20:33-37, 1981) as modified (Manavalan, P., Johnson, W. C., Jr. Anal. Biochem. 167:76-85, 1987) agreed most closely with crambin's crystal structure. This method was then applied to the CD spectra of the membrane-active toxins homologous to crambin (α1- and β-purothionin, phoratoxin A and B, an viscotoxin A3 and B).The new program SEQ (pronounced “seek”) was developed to assign the secondary structure along the protein chain in a hierarchical fashion and applied to the plant toxins. The method constrained the secondary structure fractions to those from CD analysis and combined standard statistical methods with amphipathic helix location.Both CD-arrived secondary structure percentages and sequence assignment indicate that the viscotoxins are structurally most similar to crambin. Purothionin's secondary structure was predicted to be fundamentally similar to crambin's with a difference at the start of the first helix. This assignment agreed with Raman and NMR analyses of Purothionin and lends validity to the method presented here. Differences from the NMR in the CD secondary structure fraction analysis for phoratoxin suggest interference in the CD from tryptophan residues.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340040405
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