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  • Articles: DFG German National Licenses  (6)
  • 1980-1984  (6)
Source
  • Articles: DFG German National Licenses  (6)
Material
Years
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Absence of an effect of lead acetate on sperm morphology, sister chromatid exchanges or on micronuclei formation in rabbits (1982)
    Springer
    Archives of toxicology 50 (1982), S. 149-157 
    Details
    ISSN: 1432-0738
    Keywords: Lead ; Sperm ; SCE ; Micronuclei ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The influence of lead on sperm morphology, sister chromatid exchanges or on micronuclei formation was studied on male rabbits after exposure to doses of 0, 0.25, and 0.50 mg lead acetate/kg body weight subcutaneously injected three times a week during 14 weeks, each on a group of five rabbits. At the end of exposure phase the lead in blood concentrations of the three groups of rabbits were 0.32, 2.57, and 2.97 μmol/l respectively. The results did not show any evidence of treatment related effects on sperm count or on morphologic abnormalities of the sperms, neither on the histopathology of the testis. Statistical analysis of the number of sister chromatid exchanges per metaphase in lymphocytes indicated no differences between the groups. Also no dose dependent effect was observed on the relative number of micronuclei in bone marrow erythrocytes. The different susceptibility to lead in different organ systems of the rabbits was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00373397
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    A light microscopic study of the development and behaviour of the synaptonemal complex in spermatocytes of the mouse (1981)
    Springer
    Chromosoma 83 (1981), S. 409-418 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A method is presented for the sequential analysis of male meiosis using hydroxyurea (HU). HU produces a gap in the spermatogenic line. The front of surviving cells behind the gap was examined day by day using silverstained whole mount spreads on glass slides. With this method it was possible to study the development and behaviour of the synaptonemal complex (SC) in mouse spermatocytes by the light microscope. At zygotene no unpaired axial elements could be seen. Unpaired axial elements were found to be specific for the diplotene stage. The axes of the XY pair could be recognized from late zygotene up to diplotene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327362
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The behaviour and structure of the sex chromosomes in spermatocytes of Microtus oeconomus (1983)
    Springer
    Genetica 61 (1983), S. 113-117 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The meiotic behaviour and structure of the sex chromosomes of Microtus oeconomus (2n=30) in Giemsa stained preparations are described. The X-Y pair appears as a sex vesicle at late zygotene. At late pachytene an unfolded sex vesicle is visible. A condensed sex vesicle appears during pre-diffuse diplotene and starts to unfold again during post-diffuse diplotene. At diakinesis and metaphase I the X and Y chromosomes can be recognized in an end-to-end association. During anaphase I, interkinesis and metaphase II the sex chromosomes are heteropycnotic and can therefore easily be recognized during the final stages of meiosis. During spermiogenesis the X and Y chromosomes can be identified in Giemsa stained preparations until the stage of spermatid elongation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00123221
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Location and variation of the constitutive heterochromatin in Petunia hybrida (1981)
    Springer
    Genetica 55 (1981), S. 85-91 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The location of heterochromatin in the chromosomes of Petunia hybrida (2n=14) is presented. C-banded mitotic metaphase chromosomes and carmine-stained pachytene bivalents have been studied. It is shown that the heterochromatin is predominantly located near the centromeres and at the secondary constrictions of the satellite chromosomes. The distribution of chromomeres in pachytene bivalents also reveals that heterochromatin is not restricted to distinct blocks, as is the case in tomato, but occurs in smaller chromomeres which gradually decrease in size towards the ends. Conspicuous telomeres have not been observed. Both C-banding technique and pachytene analysis demonstrate large variation of heterochromatin between different lines of Petunia. The study of pachytene morphology has been hampered by a high degree of non-specific stickiness of the bivalents. Both techniques prove to be unsuitable tools for large-scale chromosome identification of Petunia lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00135102
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Dosage effect of a gene with a regulating effect on anthocyanin synthesis in a trisomic Petunia hybrida (1981)
    Springer
    Genetica 55 (1981), S. 111-115 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A Petunia hybrida inbred line (W 28) has white flowers with red spots on the corolla. These spots are the result of back mutations of an unstable allele of the gene Anl for anthocyanin synthesis. Among the progeny of a population of selfed plants a primary trisomic with red-spotted white flowers was found. The reversion frequency was more than twice as high as compared with disomic plants of the same family. It was found that the chromosome in triplicate was not the chromosome on which the gene Anl is localized. It can be concluded that there is an independently segregating factor which influences the frequency of back mutations of the Anl locus. Twin spots were found among the flowers of the trisomic. They consisted of two adjacent sectors, one with a spot frequency equal to that of the flowers of disomic plants, and the other with a spot frequency more than twice as high as that of the trisomic. Probably an irregular distribution of the extra chromosome resulted in one sector with the normal diploid number of chromosomes, and an adjacent sector with two extra chromosomes. The reversion frequencies in the sector suggest that the factor which affects the reversion frequency of the unstable alleles of Anl exhibits a dosage effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00135104
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    A sequential analysis of the development of the synaptonemal complex in spermatocytes of the mouse by electron microscopy using hydroxyurea and agar filtration (1983)
    Springer
    Genetica 61 (1983), S. 119-129 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method is presented for sequential analysis of the development and behaviour of the Synaptonemal Complex (SC) in primary spermatocytes of male mice, using agar filtration for electron microscope grid preparation. The mice were treated with hydroxyurea (HU) to produce a gap in the spermatogenic line. The front of surviving cells behind the gap was examined day by day. The first visible parts of unpaired axial elements, with some barely recognizable paired regions were found 9 days after the last HU injection i.e. directly after the last S-phase before meiosis. During mid zygotene and late zygotene the axes of the autosomes had a fuzzy ill-defined appearance with irregular regions of apparent thickening. The axes of the XY pair could be recognized only at late zygotene. During pachytene the SCs of the autosomal pairs did not show a significant change except for a slight increase in size of the attachment points of the axial elements. On the first day of pachytene the axes of the XY pair appeared thin and long. On the second day the axes of the XY pair showed maximal pairing of about 50% of the axis of the Y chromosome. From the third to the fifth day a decrease of the paired region of the sex chromosomes was found together with an increase in thickness of the axes, which reached its maximum on the fourth day. Diplotene could be easily recognized: the autosomal axes showed a sharp, well-defined outline with thick attachment points with deltoid structure, and desynapsis was very clear. The axes of the XY pair showed variation during diplotene but on the third day of diplotene a characteristic bulging could be seen. The axes of the autosomes disappeared at this time and in most cases only the attachment points remained visible. The duration of the prophase classes of meiosis I was found to be: zygotene approximately 2 days; pachytene a little more than 5 days and diplotene approximately 3 days. Leptotene could not be traced by the method used. If it exists at all, it must be a stage of very short duration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00123222
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    Paper (German National Licenses)
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