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  • 1
    Electronic Resource
    Electronic Resource
    A colcemid-sensitive mechanism involved in regulation of chromosome movements during meiotic pairing (1982)
    Springer
    Chromosoma 85 (1982), S. 611-618 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Active movements of the chromosomes may be needed in the process, where homologous chromosomes find each other during the meiotic pairing. Because the components of the cytoskeleton are generally believed to be responsible for all movements in living nonmuscle cells, we have analyzed the regulation of the movements of zygotene chromosomes in the male rat by using specific inhibitors of the assembly of the various components of the cytoskeleton. — Colcemid, an inhibitor of microtubule formation, completely inhibited the chromosome movements in vitro at a concentration of 1 μg/ml. This was associated with a damage of the nuclear envelope revealed by the electron microscopic analysis. Another inhibitor of microtubule formation, vinblastine, was ineffective below the level of general toxicity (100 μg/ml). A specific microfilament inhibitor, cytochalasin B was similarly ineffective. — The findings suggest the presence of a specific colcemid-sensitive mechanism in the nuclear envelope of the zygotene spermatocytes, which regulates the movements of the chromosomes during meiotic pairing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330775
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  • 2
    Electronic Resource
    Electronic Resource
    Extracellular Matrix in Testicular Differentiation (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 438 (1984), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1984.tb38302.x
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  • 3
    Electronic Resource
    Electronic Resource
    CYTOPLASMIC FILAMENTS IN FETAL LEYDIG CELLS (1982)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 383 (1982), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1982.tb23214.x
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  • 4
    Electronic Resource
    Electronic Resource
    Differentiation of smooth muscle cells in the fetal rat testis and ovary: localization of alkaline phosphatase, smooth muscle myosin, F-actin, and desmin (1992)
    Springer
    Cell & tissue research 268 (1992), S. 521-530 
    Details
    ISSN: 1432-0878
    Keywords: Development, ontogenetic ; Testis ; Ovary ; Muscle, smooth ; Alkaline phosphatase ; Myosin ; Actin ; Desmin ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The histochemical demonstration of alkaline phosphatase (AP) activity and localization of smooth muscle myosin (SMM), F-actin, and desmin were carried out on frozen sections of testes and ovaries from 15-day-old fetal to newborn rats. The presence of immunocytochemically localized SMM and desmin was confirmed by Western blot analysis of proteins from isolated gonads. The development of smooth muscle cells was predominant in the testis. The first SMM-positive cells with an increasing intensity for F-actin and desmin appeared in the testicular tunica albuginea and around the testicular cords by the age of 16 days. A continuous layer of SMM- and F-actin-positive (but not uniformly desmin-positive) myoid cells was detected in the newborn testis. In the early gonads and in the newborn ovary, a majority of the interstitial cells expressed desmin, indicating that, in undifferentiated tissues, non-myogenic cells may also express desmin. During fetal development, male and female gonocytes showed a decrease in F-actin content but retained their high AP activity. In the cortex of the newborn rat ovary, the observed high AP activity and the presence of desmin may be associated with the postnatal histogenesis of the follicles. The presence of SMM-containing cells in the hilus of the ovary may be required for the demarcation of the ovary from the mesonephros by the constriction of the mesovarium. The occurrence of SMM-positive cells predominantly in male fetuses suggests that the development of the contractile cells in the fetal testis may be induced by testicular androgens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319159
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  • 5
    Electronic Resource
    Electronic Resource
    Magnetization transfer of pure DNA and purified sperm nuclei (1996)
    Springer
    Magnetic resonance materials in physics, biology and medicine 4 (1996), S. 135-138 
    Details
    ISSN: 1352-8661
    Keywords: magnetization transfer ; DNA ; chromatin ; sperm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics
    Notes: Abstract Magnetization transfer (MT) imaging provides a novel opportunity to characterize interactions between tissue water and macromolecules. Although severalin vitro investigations have shown that proteins and lipids are important determinants of MT, the contribution of DNA is still unknown. This study was designed to determine whether DNA and cell nuclear material exhibit MT. We measured the magnetization transfer effect of pure DNA strands and purified bovine sperm head nuclei. Although no transfer of magnetization could be detected in samples of pure DNA strands, the sperm head nuclei exhibited a strong MT effect that increased with increasing solid content of the samples. Since the purified bovine sperm head samples consist of large nuclei with only minor traces of perinuclear matrix, the measured MT effect arises from the chromatin of the nuclei. The DNA fills 90% of the nuclear volume and it is extremely tightly packed as chromatin fibers by nucleoproteins. We hypothesize that the numerous intra- and intermolecular disulfide bonds that stabilize the chromatin fibers restrict the movement of the surface water binding sites of both DNA and protamines and thus facilitate the transfer of magnetization. Therefore, the results indicate that the amount of nuclear material may positively contribute to MT in tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01772520
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  • 6
    Electronic Resource
    Electronic Resource
    Immunocytochemical detection of actin and 53 kDa polypeptide in the epididymal spermatozoa of rat and mouse (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 240 (1994), S. 516-527 
    Details
    ISSN: 0003-276X
    Keywords: Spermatozoa ; Actin ; 53 kDa protein ; Immunocytochemistry ; Rat ; Mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Presence of immunocytochemically detectable actin in the rat and mouse sperm head has been enigmatic for years. In this study, we demonstrate actin in the perinuclear theca and show that the detection of actin epitopes in the rat and mouse epididymal spermatozoa can effectively be enhanced by pre-extraction of sperm cells with SDS.Methods: The study with one monoclonal and one polyclonal anti-actin antibody was carried out at conventional and confocal fluorescence and electron microscope level, and by immunoblotting of proteins isolated from the head and tail fractions.Results: In the head of the control methanol-acetone fixed rat spermatozoa, the polyclonal antibody gave a stronger immunostaining in the postacrosomal area and in the perforatorium than the monoclonal antibody. In the mouse sperm head, the monoclonal antibody labeled the ventral edge of the postacrosomal area and slightly the perforatorium, whereas the polyclonal antibody stained the entire perinuclear space. In the SDS-extracted spermatozoa, an intense postacrosomal and perforatorial labeling was obtained with both antibodies but, in particular in the rat spermatozoa, the middle lateral portion of the postacrosomal segment remained unlabeled. Sonication seemed to cause structural modifications which specifically impeded staining with the monoclonal antibody. Both antibodies detected actin in the basal plate and the monoclonal antibody in the neck. Amorphous matrix of the connecting piece showed immunogold labeling. In the tail, the monoclonal antibody recognized actin and a relatively basic 53 kDa polypeptide, whereas the polyclonal antibody reacted with several protein bands. SDS-soluble actin of the tail was addressed to the midpiece and the SDS-insoluble 53 kDa protein profoundly to the outer dense fibers of the principal piece.Conclusions: Intense labeling of actin in the SDS-extracted rat and mouse spermatozoa was presumably due to the generated demasking of actin epitopes embedded in the perinuclear cytoplasm. The results are important in confirming that actin in the rat and mouse sperm head is not lost during spermiogenesis but apparently contributes to the three-dimensional packing of the mature perinuclear cytoplasm. This study further demonstrates the importance of the methods used in sample preparation and advantages of conofocal microscopy when attempting to detect cytoskeletal proteins which, as in spermatozoa, may occur in small quantities. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092400409
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  • 7
    Electronic Resource
    Electronic Resource
    Actin, α-actinin, and spectrin with specific associations with the postacrosomal and acrosomal domains of bovine spermatozoa (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 241 (1995), S. 77-87 
    Details
    ISSN: 0003-276X
    Keywords: Spermatozoa ; Actin ; α-actinin ; Spectrin ; Acrosomal lamina ; Bovine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Characteristic membrane changes in spermatozoa culminating in acrosome reaction and sperm-egg fusion, and suspected involvement of actin-containing cytoskeleton in membrane changes in general, prompted us to investigate subcellular distribution of actin and actin-binding proteins in bovine spermatozoa subjected to various extractions which sequentially denude the sperm investments.Methods: Spermatozoa were treated with either 1% SDS, 0.1% Triton X-100, 0.1% Hyamine, or 1 M MgCl2 or were sonicated. Immunostaining of actin, α-actinin, spectrin, and acrosin as well as electron microscopic analysis of extracted spermatozoa were carried out.Results: Extractions caused evagination of the acrosomal lamina which retained focal contacts with the inner acrosomal membrane. Extractions further revealed lateral prongs at the anterior border of the postacrosomal sheath. Labeling for α-actinin and spectrin was localized in the acrosinpositive acrosomal lamina, neck, and principal piece, the latter containing also relatively extraction-resistant oligomeric or polymerized actin. In the postacrosomal area, actin was accumulated in the extraction-resistant posterior ring structure and anteriorly at the sites apparently related to the lateral prongs. Notably, spectrin reactivity was enhanced by MgCl2 in head, neck, and principal piece, and sonication abolished cytoskeletal immunoreactivity in the head.Conclusions: Destabilization of membranes with selected extractions induces changes in the acrosomal lamina mimicking acrosomal vesicle formation. The lateral prongs and posterior ring structure, respectively, may serve as anterior and posterior anchors for the extraction-resistant post-acrosomal sheath. The lateral prongs may also be a merger zone for actin, α-actinin, and spectrin with important implication on sperm function. The latter two proteins may be involved in acrosomal vesicle formation. It is apparent that extractions have a significant effect on the detectability of sperm cytoskeletal elements. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092410111
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  • 8
    Electronic Resource
    Electronic Resource
    Extractions reveal specific argentophilic proteins in rat and bull sperm heads (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 239 (1994), S. 126-136 
    Details
    ISSN: 0003-276X
    Keywords: Argentophilic proteins ; Extraction ; Western blot ; Spermiogenesis ; Spermatozoa ; Rat ; Bovine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Silver-stainability (argentophilia) of cytoplastmic structures occurring in spermatids have been localized into the organizing perinuclear theca, but the biochemical nature and structural associations of these proteins with the cytoskeletal and membranous elements are unresolved and, therefore, were the aim of the present study.Methods: Light and electron microscopic analysis of the silver-stainability in the rat spermatids and spermatozoa was carried out in the intact testis tissue and epididymal spermatozoa and after their chemical and mechanical extraction. Correlation of argentophilia with specific proteins of rat and bovine spermatids and spermatozoa was investigated using a recently developed technique for silver nitrate staining of proteins on nitro-cellulose.Results: Sequential formation of the silver-stainable domains seemed to proceed from the argentophilic acrosomal ring. Various extractions indicated that argentophilia in the spermatids and spermatozoa was mainly associated with the perinuclear theca and to some extent to the plasma membrane. Hyamine-soluble extract from spermatozoa of rat and bull revealed only a single argentophilic protein of 130 kDa. Hyamine and SDS-soluble extracts of rat testis tissue contained an additional group of argentophilic polypeptides of lower molecular weight (115, 94, 36, 23, and 21 kDa).Conclusions: Reduction in the number of argentophilic proteins appears to be involved in a series of changes in the cyto-architecture of developing spermatids. Tentative cytoskeletal nature of argentophilic proteins remains to be identified. Nevertheless, they may have important physical relations with the higher-order organization of the sperm head cytoskeleton and overlying membranes. © 1994 Wiley-Liss, Inc.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092390203
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  • 9
    Electronic Resource
    Electronic Resource
    Expression of type I and III collagen during morphogenesis of fetal rat testis and ovary (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 219 (1987), S. 91-101 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The distribution of interstitial collagen type I and III was studied immunocytochemically and ultrastructurally in the fetal rat testis and ovary from the undifferentiated stage (day 12) until birth. The results suggest that there is a correlation between the differentiation, organization, and abundance of the mesenchyme and the differentiation of the testicular vs. ovarian cords. Type III collagen was already present in the undifferentiated gonadal mesenchyme, and it appeared at an early stage around the organizing gonadal cords. Type I collagen appeared later in a similar mesenchymal distribution as type III collagen. Fragmentation of the subepithelial basement membrane in the gonads starting morphogenesis was considered to indicate that the surface epithelium participates in the gonadal cord formation. The expression of type III collagen at first on the surface of the developing testicular cords and later around the ovarian cords suggests that the mesenchymal premyoid cells are actively involved in the male cord formation. Focal discontinuities were found in the basement membrane of the ovarian cords, which in part were separated from each other by a ramified and relatively sparse mesenchyme. A complex linkage between the cytoskeleton and the extracellular matrix is illustrated both in the cord forming Sertoli and granulosa cells, and in the adjacent mesenchymal cells. Depletion of the mesenchyme and the basement membrane around the germ cell-granulosa cell associations of the wide ovarian medullary cords may be causal for their subsequent degeneration.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092190115
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  • 10
    Electronic Resource
    Electronic Resource
    Localization of actin, α-actinin, and tropomyosin in bovine spermatozoa and epididymal epithelium (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 233 (1992), S. 61-74 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Actin, α-actinin, and tropomyosin were localized in the testicular, epididymal, and ejaculated spermatozoa and in the epithelium of the bovine epididymis by means of specific antibodies using an indirect immunofluorescence technique. Immunocytochemical results were confirmed by the western blot analysis. Independent of the method of fixation, washing, or sonication, actin, α-actinin, and tropomyosin were all consistently localized in the neck of the spermatozoa. Actin and tropomyosin present in the postacrosomal area could be removed by sonication, whereas α-actinin in the basal plate appeared to be resistant to the treatment. In the unwashed spermatozoa α-actinin-specific immunofluorescence was seen over the acrosomal area, whereas in the washed sperm it appeared as a narrow cap at the margin of the head. In the latter location, its distribution was similar to that of tropomyosin. In the majority of preparations, tropomyosin could be localized in the principal piece of the tail. Even though some actin-specific immunofluorescence could be identified in the principal piece of the tail of the testicular and epididymal spermatozoa, a strong immunoreaction appeared only in the ejaculated spermatozoa. In the principal cells of the epididymal epithelium, specific fluorescence for actin, α-actinin, and tropomyosin occurred in the apical junctional complex. Basal bodies of the solitary cilia of the epididymal epithelium were labelled with antitropomyosin and anti-α-actinin antibodies. Besides offering new information about the cytoskeletal composition of the mammalian sperm, the present results support the hypothesized homology between the connecting piece of the sperm neck and the basal body of the cilia. © 1992 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092330109
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