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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 62 (1984), S. 953-962 
    ISSN: 1432-1440
    Keywords: Purine metabolism ; Enzyme defects ; Molecular mechanisms ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An overview of inherited disorders of purine metabolism, concentrating on well established enzyme defects is given. Included are HPRT and the LNS, APRT and 2,8-dihydroxyadenine lithiasis, hyperactivity of PRPP synthetase, ADA and PNP and immunodeficiencies. Emphasis is put on underlying molecular mechanisms on the gene-, enzyme-, or metabolite level for a better understanding of the events leading from the genotype to the clinical phenotype. Finally some aspects of extracellular purine nucleotide metabolism catalyzed by cell surface-bound ectoenzymes are discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2072
    Keywords: Phenylethylamine ; Genetics ; Heritability ; Recombinant inbred strains ; Locomotor ; Amphetamine ; Schizophrenia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract β-Phenylethylamine (PEA) is an amphetaminelike compound that is postulated to be a possible endogenous psychotogen. We studied locomotor response to PEA in two inbred progenitor strains of mice (C57BL/6 By and BALB/c By), their reciprocal F1 hybrids (B6CF1 and CB6F1), and seven recombinant inbred strains (CXBD, CXBE, CXBG, CXBH, CXBI, CXGJ, and CXBK). Univariate and multivariate statistical analyses were done. Heritability of the response to PEA was 82%. The strain distribution pattern was suggestive of the inheritance of the trait through a single major gene locus.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Genetics ; blood groups ; acetylator phenotype ; blood glucose ; M value ; Type 1 diabetes ; Type 2 diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The acetylator phenotype and ABO blood groups were evaluated in 55 normal subjects and in 156 diabetic patients [61 with Type 1 (insulin-dependent) diabetes and 95 with Type 2 (non-insulin-dependent) diabetes]. The prevalence of fast acetylators was significantly higher in the Type 1 diabetic patients (53%) than in the control subjects (29%). In the Type 2 diabetic patients the prevalence was 39%, and thus not signifi cantly different from the control or Type 1 diabetic groups. In the Type 2 diabetic patients, but not in the control or in the Type 1 diabetic subjects, an association between the fast acetylator phenotype and the B blood group was found.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2072
    Keywords: Apomorphine ; Dopamine ; Stereotypy ; Hypomotility ; Roman High and Low Avoiders ; Genetics ; Dopamine receptors ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two experiments were carried out to investigate differences in the behavioural responses to “high” and “low” doses of apomorphine in two strains of rats selectively bred for high and low avoidance on a two-way active avoidance task: the Roman High and Low Avoiders. Significant strain differences were found in the stereotypy resulting from a high dose of apomorphine (2 mg/kg s.c.). In a second experiment no strain differences were, however, apparent for the hypomotility produced by low doses of the drug (0.05 mg/ kg s.c.). Pretreatment with a low dose of apomorphine had no effect on the stereotypy response when the animals were subsequently retested with the high dose. These results may indicate differential sensitivities of dopamine receptors in these strains.
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  • 5
    ISSN: 1432-2242
    Keywords: Triticum aestivum L. ; Doubled-haploids ; Genetics ; Androgenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Plants of three common wheat (Triticum aestivum L. em. Thell) cultivars and one randomly selected doubled-haploid line derived by anther culture from each of the three cultivars were each grown in three environments, a field environment, a greenhouse environment, and a growth chamber environment. Anthers containing largely miduninucleate to late uninucleate microspores were cultured and calli were induced to regenerate plants in order to assess the effects of cultivar, cultivar family (cultivar and corresponding doubled-haploid derivative), anther-donor plant environment, and cultivar X environment interaction on androgenic responses. Large differences in response were observed among cultivars as well as between cultivars and doubled-haploids. Differences between cultivar and doubled-haploid within cultivar family usually resulted from higher frequency of response in the cultivar, contrary to the hypothesis that anther culture per se constitutes a general selective device for superior androgenic responses. Also, in a second experiment, anther callusing frequency was greater in the cultivar ‘Kitt’ than in any of five unique doubled-haploid lines derived from ‘Kitt’. Significant effects were also observed in the first experiment for the interactions of cultivar family X environment as well as doubled-haploid vs. cultivar X environment, although the effect of environment itself was less significant than these interactions.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 67 (1984), S. 97-111 
    ISSN: 1432-2242
    Keywords: Genetics ; Nitrogen ; Grain crops ; Selection ; Plant breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It is necessary to increase protein productivity of grain crops to meet present and future world protein requirements. Conventional plant breeding methodology has been to select genotypes with enhanced yield or grain protein concentration. In addition to this determination of end product, we suggest measurements of a number of physiological and biochemical processes of nitrogen (N) metabolism which precede plant maturity as selection criteria for enhanced N metabolism and grain crop productivity. The measurement across the growing season of genotypic variation in components of N metabolism would constitute a physiological/biochemical selection program to be incorporated with the determination of harvestable end product. A properly designed physiological/biochemical selection program would integrate the effects of plant genotype, environment, and their interactions allowing identification of the factors limiting productivity of particular genotypes, and would also estimate end product. Our review of literature pertinent to whole plant N metabolism suggests that such a selection program initially include NO 3 - uptake, N2 fixation, N accumulation, N remobilization, seed protein synthesis, and Nitrogen Harvest Index.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 69 (1984), S. 15-21 
    ISSN: 1432-2242
    Keywords: Genetics ; Heat tolerance ; Thyroid function ; Chickens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Five experiments were conducted to assess the genetic variation in thyroid function (T3, T4), body weight and heat stress survival time in chickens. Thyroxine (T4) levels were found to be elevated in response to 4 and 8 μg bovine thyroid stimulating hormone (TSH) in experiment I. In experiment II, 4 μg of TSH was injected into chickens from 30 sire families of the Athens-Canadian Randombred population. The heritability of T4 levels after TSH injection was high. In experiment III, families identified as having innate high or low T4 levels after TSH injection and a group of control birds were subjected to a heat Stressor of 50 °C for up to 240 min at six weeks of age and heat stress survival time was studied. The groups did not differ from each other in heat stress survival time. Experiment IV was similar to experiment I except triiodothyronine (T3) was also measured after TSH injection. Both T4 and T3 levels after TSH injection were moderately heritable. In experiment V birds were reared to six weeks of age and heritability calculated for body weight, T4, T3, and heat stress survival time. Heritabilities were high for body weight, moderate for T4 and heat stress survival time, and low for T3. Phenotypic correlations were significant and negative for heat stress survival time with body weight and T4, and for body weight with T3 after TSH. Significant positive correlations were found for T4 with T3 after TSH and also T4 and body weight. Analysis of genetic correlations suggested that none of the traits studied would be an adequate selection parameter for achieving heat tolerance without reducing body weight.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 1-25 
    ISSN: 0192-253X
    Keywords: maize ; endosperm ; mutants ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 43-58 
    ISSN: 0192-253X
    Keywords: ciliate genetics ; Tetrahymena malaccensis ; karyonidal inheritance ; macronuclear assortment ; selfing ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mating type determination in Tetrahymena malaccensis is karyonidal, ie, the four new macronuclei developing in a single conjugating pair are independently determined as to which of the six known mating types they will express. Occasional selfing clones are similar to those in T thermophila, in that any one is capable of stabilizing at a restricted range of mating types. The genetic basis of mating type potentialities is incompletely resolved. T malaccensis may, like T thermophila and T canadensis, have a single multiallelic locus that controls the array of types. Quantitative considerations suggest, however, that other loci may be involved.
    Additional Material: 1 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 83-91 
    ISSN: 0192-253X
    Keywords: temporal genes ; acid hydrolases ; liver ; mice ; hepatocytes ; nonhepatocytes ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The cell specificity of expression of three distinct trans acting temporal gene systems determining the developmental control of α-galactosidase, β-galactosidase and β-glucuronidase was tested in mouse liver. For α-galactosidase and β-galactosidase, expression was limited to hepatocytes; no effect was seen in nonhepatocytes. For β-glucuronidase the data suggest that expression of the Gus-t temporal locus is also limited to hepatocytes, and that the smaller enzyme reduction seen in nonhepatocytes of some strains is due to a separate systemic regulatory locus that is also present in the [Gus] gene complex. We conclude that the temporal gene-determined timing mechanisms initiating switches in rates of enzyme synthesis are intrinsic to the cells themselves and are not communicated to adjacent cells. This conclusion applies to the temporal locus for β-glucuronidase that is proximate to its structural gene as well as those for α-galactosidase and β-galactosidase that are distant from the structural genes that they regulate.
    Additional Material: 5 Tab.
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  • 12
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 117-127 
    ISSN: 0192-253X
    Keywords: temporal-regualatory variation ; isocitrate dehydrogenase ; rainbow trout ; Salmo gairdneri ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We examined a temporal series of embryos from 14 full-sib families of rainbow trout with starch gel electrophoresis to determine the time of initial detection of enzyme produced by ldh-3. Maternal enzyme was detected in unfertilized eggs, whereas paternal alleles showed evidence of initial expression after gastrulation and epiboly. Two alleles, 40 and 71, were expressed synchronously several days before the 114 allele. Measurement of enzyme activity by spectrophotometric analysis and serial dilution supported these observations. The degree of delay of expression of the 114 allele between families was coupled with other estimates of developmental rate. These data suggest the existence of allelic variation at a cis-acting genetic element controlling the pattern of ontogenetic expression of structural alleles at Idh-3.
    Additional Material: 2 Ill.
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  • 13
    ISSN: 0192-253X
    Keywords: Drosophila melanogaster ; ts-mutants ; adenylate cyclase ; Phosphodiesterase ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The mode of the developmental expression of adenylate cyclase (AC) and phosphodiesterase (PDE) in D melanogaster indicates that PDE plays the major role in the maintenance of a certain level of cAMP in postembryonic development, while both enzymes function in concert in imago. The ts-mutants ts155 and ts622, characterized upon their isolation as having an increased cAMP content and normal PDE activity, manifest high levels of AC activity from the third day of imago life. The levels of PDE activity characteristic for adult mutants with altered enzyme activity (low in ts66 and ts980, high in ts398) are manifested in ts980 from larval instar II, and from the larval instar III in ts398 and ts66. Data on the dependence of PDE activity in adults upon temperature of incubation, being in agreement with the expectations for a ts-mutation in a gene coding for a form of PDE in case of ts66, suggest that ts398 affects not the enzyme-coding gene but rather one for an activator protein. The fact that in ts398 (the polyphasic ts-lethal mapping to 1-38.9) 1) AC activity is somewhat higher than normal at 22°C and is readily activated at 29°C, 2) activity of PDE-I assayed in heat-pretreated homogenates is higher than normal, 3) that boiled extracts of ts398 are potent activators of the wild type and of its own PDE-I indicates that it is a mutation affecting calmodulin, which is known to be stable at boiling and capable of activating both AC and PDE-I. Data on Ca2+ and EGTA effects suggest that the mutation presumably increases Ca2+-binding activity of calmodulin, ts980 and ts622, in which ts-lethality could be produced only by certain doses of haloperidol and triftazine, appear to be lethal in compounds with ts398, thus indicating that these mutations could affect the same calmodulin-controlling gene.
    Additional Material: 6 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 201-207 
    ISSN: 0192-253X
    Keywords: rDNA ; compensation ; rRNA-DNA hybrids ; restriction analysis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The compensatory response is a regulatory event influencing the redundancy of the ribosomal RNA cistrons (rDNAs) of Drosophila melanogaster. In this report we attempt to demonstrate that the compensatory event and the thymidine analogue bromodeoxyuridine (BrdU) specifically interact. We conclude that the drug inhibits the compensatory response of Drosophila melanogaster XO males and argue that the compensatory event is not the passive consequence of replicational dominance known to occur in Drosophila polytene tissues.
    Additional Material: 2 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 239-239 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 0192-253X
    Keywords: gonad differentiation ; gene expression ; two-dimensional micro gel electrophoresis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Gonadal protein patterns were studied during development in the rat by two-dimensional micro-gel electrophoresis. Specific proteins were detected in both the male and the female sex at the morphologically indifferent state (two female- and one male-specific) and during differentiation. At the onset of gonadal differentiation (day 14) two additional sex-specific proteins were discovered in the male and two in the female. These proteins remained expressed during further development. One testicular protein was restricted to the cytosol of the tunica albuginea. The other one was absent from the tunica. In the female gonad, the two proteins were membrane-specific, one present in germ cells, the other in somatic cells. In the testis, one additional protein was discovered at postnatal day 1. Thus according to biochemical criteria there is no indifferent state of gonadal development. The testis and ovary express sex-specific genes both before and after the onset of gonadal differentiation.
    Additional Material: 8 Ill.
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  • 17
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 93-102 
    ISSN: 0192-253X
    Keywords: pattern formation ; cell-lethal mutations ; imaginal discs ; cell death ; pattern triplications ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effects of 48-hr 29°C temperature treatments on the imaginal leg discs of Drosophila hemizygous for a temperature-sensitive cell-lethal mutation were examined to determine whether the induction of patches of cell death in the imaginal discs is a prerequisite for the induction of pattern triplications. In a statistical analysis, the frequency of induction of cell death was found to be highly correlated with the frequency of induction of triplications. In addition, individual discs in which cell death had been induced were cultured and found to triplicate at frequencies significantly greater than discs with no visible cell death, or unselected discs from the same larvae.
    Additional Material: 3 Ill.
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  • 18
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 103-114 
    ISSN: 0192-253X
    Keywords: Drosophila ; pupation ; larval moults ; Lethalcryptocephal ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The events of normal pupation in Drosophila melanogaster are described in detail from the time of gas bubble expulsion until the completion of pupation with the eversion of the cephalic complex. The importance of the internal gas bubble for posterior movement of the prepupa is examined and its relation to the expulsion of the larval mouthparts and the creation of the anterior gas space described.The phenotype of lethalcryptocephal homozygotes, which characteristically cannot evert their heads, is re-examined. Observations of larval lethality and multiple mouthparts in 1 (2)crc larvae and pupae are described. These new aspects of the mutant phenotype are discussed with respect to the abnormalities of pupation. Fristrom's hypothesis that the basic mutant lesion is an increased stiffness of the pupal cuticle due to an excess chitin deposition is re-evaluated.
    Additional Material: 5 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 173-175 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 179-180 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 21
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 219-225 
    ISSN: 0192-253X
    Keywords: actin ; gene regulation ; development ; Drosophila ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Extreme and rapid changes in the synthesis of messenger RNAs and proteins accompany differentiation in wing tissues of Drosophila. Of the six actin genes, at least three are expressed in wing cells, some during the most extreme changes in cell shape. However, different messages of the set appear, decay, and reappear on a regulated temporal program. These results show that actin expression is stage-specific in a single cell type.
    Additional Material: 3 Ill.
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  • 22
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 115-116 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 23
    ISSN: 0192-253X
    Keywords: Tetrahymena ; Paramecium ; mating type differentiation ; intranuclear coordination ; macronuclear molecular cloning ; ARF ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mating type determination in Tetrahymena thermophila involves developmentally programmed, heritable alterations of the macronucleus, localized to the mtd locus. This determination can be predictably controlled by the environmental conditions during macronuclear development, eg, temperature and time of refeeding. In this article we have further characterized the effects of delayed refeeding on mating type determination, as revealed by the frequency of mating types among the progeny of a cross. Our results show that 1) the magnitude of this starvation effect decreases with temperature of conjugation and becomes undetectable at 18°C; 2) starvation during the interval 14 to 22 hr (after conjugation is induced at 30°C) is a necessary and sufficient condition for the induction of starvation effects; 3) relative mating type frequencies vary monotonically with nutrient concentration present during this critical period; and 4) sister macronuclei, developing under starvation conditions in the same cytoplasm, differentiate majority mating types characteristic of early or late refeeding; sister macronuclei show no apparent correlation with each other. On the basis of our observations on early and late refed cells, we propose that the composition of the newly developed macronucleus is the outcome of two key events: 1) mating type determination at the mtd locus and 2) differential molecular cloning of generally one or two autonomously replicating fragments (ARFs) of the macronuclear DNA bearing the mtd locus.
    Additional Material: 5 Ill.
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  • 24
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 63-63 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 25
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 73-82 
    ISSN: 0192-253X
    Keywords: axolotl ; isozymes ; phosphoglucomutase ; esterase ; G-K mapping ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Four isozyme systems were surveyed in our laboratory-bred colony of axolotls (Ambystoma mexicanum) to determine whether there were elecrophoretic variants that could be used as markers in developmental experiments. For malate dehydrogenase (MDH), lactate dehydrogenase (LDH), and phosphoglucomutase (PGM), the best separations were obtained by isoelectric focussing on polyacrylamide slab gels, whereas for soluble esterases (Est), conventional polyacrylamide gel electrophoresis was used. The patterns for both MDH and LDH were consistent with two-locus models, but no variation was obtained. The results for PGM support a single-locus model with two alleles that are expressed codominantly in heterozygotes. There is also evidence for a third, null allele. The pgm gene maps approximately 24 map units from its centromere. The majority of the animals tested produced four esterase bands. We propose that each is controlled by a separate locus. One of the bands, Est-3, is absent in some animals. The results of various crosses support the proposition that these animals are homozygous for a null allele. The est-3 gene is distant from its centromere.
    Additional Material: 2 Ill.
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  • 26
    ISSN: 0192-253X
    Keywords: 5S ribosomal RNA genes ; rearrangement ; macronuclear development ; macronuclear replication ; Tetrahymena thermophila ; determination ; phenotypic assortment ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The organization of the 5S rRNA genes in the MACronuclear genome of Tetrahymena thermophila was examined during MAC development and replication. The 5S genes are arranged in several tandem arrays of alternating transcribed and spacer sequences in both MICronucleus and MAC. The number of EcoRI fragments bearing 5S gene clusters is similar in MIC and MAC. Most fragments occur in both the MIC and newly formed MAC genomes, a few being MIC-limited and a few MAC-limited. The same rearrangements are seen in the MACs of all four caryonides of a mating pair, and most rearrangements are seen in the newly formed MACs of different inbred strains. During replication of the MAC about half the fragments bearing 5S gene clusters disappear in different cell lines, and new fragments containing 5S genes appear. These fragments differ in size from those present in the MIC or newly formed MAC. These alterations occur in the MACs of all strains except strain B, which is more resistant to vegetative rearrangement. The losses and gains of fragments occur during clonal propagation of cell lines. The process begins by 35 fissions following conjugation, but once an alteration occurs, it is stably propagated. Clonal variation occurs with respect to which losses and gains occur, although a nonrandom distribution is seen among cell clones. We conclude that the alterations in MAC fragment size occur at two stages in the life cycle of Tetrahymena. The first stage occurs during conjugation, when the MAC develops from the MIC. The second stage becomes manifest during vegetative growth, when DNA replication occurs in the MAC and daughter molecules are distributed “amitotically” to daughter nuclei. The two-stage character to MAC alterations for the 5S genes is interpreted in terms of the two steps previously described for MAC differentiation: determination and phenotypic assortment. Possible molecular mechanisms are also discussed.
    Additional Material: 5 Ill.
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  • 27
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 129-140 
    ISSN: 0192-253X
    Keywords: avian developmental antigens ; hybrids ; erythroid subpopulations ; species restriction ; monoclonal antibodies ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Monoclonal and polyclonal antibodies were used to examine the expression of three erythroid developmental antigen systems in the chicken, Japanese quail, and quail-chicken hybrid. Chicken fetal antigen (CFA), quail fetal antigen (QFA), and chicken adult antigen (CAA) each represent a series of cell-surface glycorproteins associated with the development of avian hematopoietic cells. Monoclonal anti-CFA antibodies from clones 190-4 and 288-1.1.1.2 supernatants were shown to react against epitopes associated with CFA determinants 8 and 2, respectively. Using complement-mediated microcytotoxicity, these reagents permitted the identification of different erythroid subpopulations in the neonatal chicken and hybrid; therefore, heterogeneity in cell surface CFA determinants among mature peripheral erythrocytes should serve as a useful tool for analyzing erythroid development. In the case of CAA, erythrocytes from adult hybrids were found to express the same complement of CAA determinants identified in the chicken, and CAA appeared much earlier in the hybrid than in either of the parental species. Similarly, two species-restricted fetal antigens associated with similar glycoproteins, CFA8 and QFA, had similar developmental profiles in their respective species, the chicken and quail. In contrast, these antigens were dominantly expressed but exhibited different developmental profiles on erythrocytes from the hybrids. While quail-chicken hybrids exhibited apparent genomic interactions in the expression of these developmental antigens, no evidence for the existence of hybrid-specific fetal antigens was obtained.
    Additional Material: 4 Ill.
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  • 28
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 29
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 227-238 
    ISSN: 0192-253X
    Keywords: centriole ; mitotic center ; myxomycete ; Physarum ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Amoebae of the Myxomycete Physarum polycephalum in the interphase state typically contain only one proflagellar apparatus in which the anterior kinetosome (anterior centriole) is attached to the microtubule organizing center 1 (mtoc 1). We built strains possessing more than one mtoc 1 and a variable number of anterior centrioles to allow the appearance of new structures. In 8% of the amoebae of these strains, the 1:1 attachment between the anterior centriole and the mtoc 1 is not always respected. In nine cases studied using tridimensional reconstructions from ultrastructural thin sections, the pattern of attachment was more complex. A mtoc 1 could be linked to several anterior centrioles, and/or reciprocally an anterior centriole could be linked to several mtoc 1. In one case, an anterior centriole was not linked to a mtoc 1 and in three cases, a single centriole exhibited anterior and posterior characteristics. These observations suggest that (1) each pair of centrioles constitutes a morphological and physiological entity that is distinct from the mitotic center (mtoc 1); (2) the attachment of the anterior centriole to the mtoc 1 occurs at the end of each mitosis; (3) there is an inductory process during the morphogenesis of the link between the anterior centriole and the mtoc 1; (4) the anterior characteristics of a centriole can be present in the absence of the link with the mtoc 1; (5) the anterior and posterior characteristics of a centriole are not exclusive of each other, ruling out the existence of a lineage corresponding to the anterior centriole and a lineage corresponding to the posterior centriole; and (6) the differences between anterior and posterior centrioles result from a maturation process.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 30
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 31
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 32
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 65-71 
    ISSN: 0192-253X
    Keywords: BrdU ; rDNA ; Drosophila ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We demonstrate that Bromodeoxyuridine (BrdU)-induced reductions of the ribosomal RNA cistrons (rDNAs) are observed in Drosophila virilis, and Drosophila busckii, but not in karyotypically normal adults or larvae of Drosophila melanogaster. However, BrdU does reduce the redundancy of the rDNAs of XO D melanogaster males, in which a compensatory response is evidenced in the untreated XO sibling controls. These results suggest that the BrdU-rDNA interaction is specific to events which modulate rDNA redundancy. Further, both thymidine and deoxycytidine “reverse” the BrdU effect in D virilis, an observation which is inconsistent with current working hypotheses describing the mechanisms of BrdUs effects.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 33
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 177-177 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 34
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 209-217 
    ISSN: 0192-253X
    Keywords: chick blastula ; epiblast-hypoblast interaction ; protein pattern ; primitive streak induction ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The patterns of protein synthesis are examined in the hypoblast and in the areas that comprise the epiblast, that is, the area opaca, the marginal zone, and the central area, during the blastula stage which marks the beginning of the interaction between the epiblast and hypoblast for induction of the primitive streak. The results demonstrate that there are distinct qualitative and quantitative differences in protein patterns in individual areas of blastoderm, the differences being most distinct between the hypoblast and any of the component areas of the epiblast. These differences in patterns of proteins suggest that the component areas of the chick blastula have already diverged to different developmental fates before any apparent morphogenetic differentiation, that is, the appearance of the primitive streak.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 35
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 243-244 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 36
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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