ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Structure of Dimethyl Phosphinoborine Tetramer (1962)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 84 (1962), S. 2457-2457 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00871a042
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Karyotype analysis of Meloidogyne hapla by 3-D reconstruction of synaptonemal complexes from electron microscopy of serial sections (1978)
    Springer
    Chromosoma 70 (1978), S. 131-139 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Meloidogyne hapla Race A (meiotic, n=17) females have 17 synaptonemal complexes (SC). The karyotype length is constant throughout pachytene, although nuclear volume increases as pachytene progresses. Each SC has at least one region in which two pairs of lateral elements run parallel to each other for a distance of 1–2 μm, thus forming a “double SC” (dSC). Decondensed chromatin regions (DCR) occur along some SCs and represent 5% of the length of the karyotype. The DCRs may be the location of the sex-determining chromatin. Spermatocytes from males of the same meiotic parthenogenetic race (A) have SCs and cylindrical granular complexes (CGC) while males and females from a mitotic (3n=45) parthenogenetic race (B) lack such structures. The CGCs may contribute precursors necessary for the formation of SCs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The synaptonemal complexes of Caenorhabditis elegans: Pachytene karyotype analysis of the Dp 1 mutant and Disjunction Regulator Regions (1985)
    Springer
    Chromosoma 93 (1985), S. 177-182 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The duplication mutant Dp1 presents morphological changes of the pachytene nuclei which include enlarged nuclei (58% greater than the wild type (WT)) and increased total length of the synaptonemal complex (SC) complement (32% greater than WT). The size of the nucleolus is similar to that of the wild type. The SC of the XX bivalent is 2.5 μm long which is similar to the length in other strains. Genetic analysis (Herman et al. 1976) has shown that a duplicated segment of the X chromosome has been transposed to linkage group V in the Dp1 mutant. The present analysis, however, did not reveal the expected duplication loop in bivalent V of the heterozygous Dp1 strain. There is an average of three “Disjunction Regulator Regions” (DRR) per nucleus and approximately 1% X-chromosome nondisjunction which is consistent with the notion that the presence of DRRs somehow facilitates regular disjunction of the X chromosome. Statistical analysis, based on 9 different strains and 81 nuclei, indicates that there is a good correlation between the frequency of occurrence of X-chromosome nondisjunction and the number of DRRs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293166
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The synaptonemal complexes of Caenorhabditis elegans: the dominant him mutant mnT6 and pachytene karyotype analysis of the X-autosome translocation (1986)
    Springer
    Chromosoma 93 (1986), S. 256-260 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The dominant X-autosome heterozygous translocation mutant mnT6 of the nematode Caenorhabditis elegans has an X chromosome that has been reduced in size by 40%, yet the remainder of the bivalent pairs effectively at pachytene and has a synaptonemal complex (SC) that has a normal appearance. Six SCs are present in pachytene nuclei of this mutant which correspond to a haploid value of n=6. Nondisjunction of the X chromosome occurs at a rate of 37% and there are no ‘Disjunction Regulator Regions’ (DRR) in this him (high incidence of males) mutant. This is consistent with the notion that DRRs either promote disjunction or inhibit nondisjunction of the X chromosome. Their occurrence in pachytene nuclei is independent of the mechanism responsible for nondisjunction, i.e. point mutations as in him-8 versus chromosomal aberrations as in mnT6. Although an SC is present along the entire length of the X chromosome, crossover suppression is observed in mnT6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292746
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Karyotype analysis ofAscaris lumbricoides var.suum (1976)
    Springer
    Chromosoma 58 (1976), S. 101-111 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Twelve synaptonemal complexes are present in both oocyte and spermatocyte pachytene nuclei ofAscaris lumbricoides var.suum, as determined by 3-D reconstruction of the nuclear contents from electron microscopy of serial sections and therefore, n=12 in the strain ofAscaris described here. In the female the heterochromatic end of each synaptonemal complex is attached to the nuclear envelope and the other end is free in the nucleoplasm. In the male neither end ot the synaptonemal complex is attached, but there is a heterochromatic knob at one end of each complex. Five additional large heterochromatic masses are present in the spermatocyte nucleus and these may be the sex chromosomes described by earlier workers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00701353
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Precocious formation of synaptonemal-like polycomplexes and their subsequent fate in female Ascaris lumbricoides var. suum (1977)
    Springer
    Chromosoma 65 (1977), S. 21-35 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract During meiotic interphase, before leptotene, synaptonemal-like polycomplexes are seen in the cytoplasm of the Ascaris lumbricoides oocytes and in the communal anucleate rachis. In some females short intranuclear synaptonemal complexes are present briefly at that early stage. The number of extranuclear complexes increases just before leptotene, some are attached to the pores of the nuclear membrane. During zygotene most polycomplexes disappear. At late pachytene they reappear in some females but not in others. The morphology, when first seen, is that of disorganized filamentous bodies, later lateral elements appear among the filaments. The dimensions of the lateral elements of the polycomplexes are variable. In the male the distribution of polycomplexes among the rachis, the cell cytoplasm, and at the nuclear envelope is similar to that observed in the female. These observations confirm the precocious occurrence of synaptonemal-like polycomplexes reported by Bogdanov (1977). Ascaris lumbricoides thus, uniquely, appears to manufacture synaptonemal complex-like material in the communal cytoplasm of the germ cells prior to the time that the full complement of synaptonemal complexes appears in the nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293128
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Occurrence of synaptonemal complexes and recombination nodules in a meiotic race of Meloidogyne hapla and their absence in a mitotic race (1978)
    Springer
    Chromosoma 68 (1978), S. 91-100 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The early prophase of the first maturation division of oocytes is compared in two races of Meloidogyne hapla Chitwood. Light microscopic analysis suggested that chromatin of both Race A (meiotic parthenogenetic; n=17) and Race B (mitotic parthenogenetic; 3n=45) behaves similarly during early stages of maturation of oocytes (Triantaphyllou, 1966). Electron microscopic analysis shows that synaptonemal complexes and recombination nodules are observed at pachytene in Race A, but are absent in corresponding oocytes of Race B. Cylindrical granular complexes present in the cytoplasm at prepachytene stages are intimately associated with the nucleus at pachytene in Race A, but are absent in Race B.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330375
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The synaptonemal complexes of Caenorhabditis elegans (1982)
    Springer
    Chromosoma 84 (1982), S. 585-597 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Normal synaptonemal complexes (SCs), consisting of two lateral elements and a central element, are present in wild-type, him-4 and him-8 mutant strains in both hermaphrodites and males of Caenorhabditis elegans. Thus, the increase in rate of nondisjunction in the him mutants is not related to aberrant SC morphology. The wild-type hermaphrodite has six SCs, as determined from 3-D reconstruction analysis of serial sections from electron microscopy. Thus, n = 6 and this confirms early reports based on cytological studies with the light microscope. Only one end of the SC is attached to the nuclear envelope while the other end is free in the nucleoplasm and there is no apparent bouquet formation. Either end of the SC can attach to the nuclear envelope. The pairing behavior of the XX bivalent is normal and occurs synchronously with the autosomes. Electron dense bodies, or knobs, are associated with the SC via the central element and displace the chromatin for a distance of 200 nm. Each pachytene nucleus of the wild-type hermaphrodite has six such structures that are randomly dispersed along the bivalents such that some SCs have one or two knobs while others have none. Their function is unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292857
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructural analysis of sex determination in Ascaris lumbricoides var. suum (1978)
    Springer
    Chromosoma 66 (1978), S. 59-69 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract At metaphase of the first spermatocyte meiotic division in Ascaris lumbricoides var. suum the polymorphic bivalents are arranged at the equatorial plate peripheral to a central aggregate mass. The aggregate mass segregates to only one of the two daughter cells and thus behaves as a sex chromosome. The mass is comprised of two components: a granular chromatin that can be differentiated from the autosomes at metaphase I, and a condensed chromatin that has a similar morphology to the autosomes but is functionally differentiated at anaphase I. The condensed chromatin may be autosomes that have fused with the sex chromsomes and may be responsible for the segregation of the whole aggregate at anaphase I. Analysis of the origin of the mass is discussed and microtubular association in the movement of the mass is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285816
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The synaptonemal complexes of Caenorhabditis elegans: pachytene karyotype analysis of male and hermaphrodite wild-type and him mutants (1982)
    Springer
    Chromosoma 86 (1982), S. 577-593 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Only five synaptonemal complexes (SC), representing the 5 autosomes, are present in wild-type, him-4 and him-8, Caenorhabditis elegans males, whereas there are six SCs, accounting for 5 autosomal bivalents and the XX bivalent, in the C. elegans hermaphrodite. The univalent X chromosome of the male is present as a heterochromatic ‘X-body’ in spermatocyte pachytene nuclei. The XX bivalent in wild-type, him-4 and him-8 hermaphrodites (SC1, 2.5 μm in length) represented 6% of the total karyotype length and a SC of this size is missing from the respective male karyotypes. This corresponds with the fact that the total male karyotype length is only approximately 94% that of the hermaphrodite. Associated with the central element of the SC are structures termed ‘SC knobs’ that were first described in the wild-type hermaphrodite. The six SC knobs present in the wild-type hermaphrodite oocyte pachytene nuclei and the two SC knobs in the male spermatocyte pachytene nuclei are apparently randomly placed with the exception that they are never found at the ends of the SC. This is also true in him-4 and him-8 in which case there are 3 and zero SC knobs in the hermaphrodites, respectively, and one SC knob each in the male pachytene nuclei. The decrease in number of SC knobs in hermaphrodite to male represents a true sex difference. The presence or absence of the SC knobs may influence the X chromosome nondisjunction process and this effect is not localized to the region of the SC on which the SC knob is located.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330128
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...