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Dolores D. Mruk - One of the best experts on this subject based on the ideXlab platform.
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Regulation of microtubule (MT)-based cytoskeleton in the Seminiferous Epithelium during spermatogenesis.
Seminars in cell & developmental biology, 2016Co-Authors: Elizabeth I. Tang, Dolores D. Mruk, C. Yan ChengAbstract:In rodents and humans, testicular cells, similar to other mammalian cells, are supported by actin-, microtubule (MT)- and intermediate filament-based cytoskeletons. Although the cytoskeletal network of the testis serves an important role in regulating spermatogenesis during the epithelial cycle, most of the published findings in the literature are limited to studies that only visualize these cytoskeletons in the Seminiferous Epithelium. Few focus on the underlying molecular mechanism that regulates their organization in the Epithelium in response to changes in the stages of the epithelial cycle. Functional studies in the last decade have begun to focus on the role of binding proteins that regulate these cytoskeletons, with some interesting findings rapidly emerging in the field. Since the actin- and intermediate filament-based cytoskeletons have been recently reviewed, herein we focus on the MT-based cytoskeleton for two reasons. First, besides serving as a structural support cytoskeleton, MTs are known to serve as the track to support and facilitate the transport of germ cells, such as preleptotene spermatocytes connected in clones and elongating/elongated spermatids during spermiogenesis, across the blood-testis barrier (BTB) and the adluminal compartment, respectively, during spermatogenesis. While these cellular events are crucial to the completion of spermatogenesis, they have been largely ignored in the past. Second, MT-based cytoskeleton is working in concert with the actin-based cytoskeleton to provide structural support for the transport of intracellular organelles across the cell cytosol, such as endosome-based vesicles, and phagosomes, which contain residual bodies detached from spermatids, to maintain the cellular homeostasis in the Seminiferous Epithelium. We critically evaluate some recent published findings herein to support a hypothesis regarding the role of MT in conferring germ cell transport in the Seminiferous Epithelium.
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Germ Cell Transport Across the Seminiferous Epithelium During Spermatogenesis
Physiology (Bethesda Md.), 2014Co-Authors: Xiang Xiao, Dolores D. Mruk, Chris K.c. Wong, C. Yan ChengAbstract:Transport of germ cells across the Seminiferous Epithelium is crucial to spermatogenesis. Its disruption causes infertility. Signaling molecules, such as focal adhesion kinase, c-Yes, c-Src, and intercellular adhesion molecules 1 and 2, are involved in these events by regulating actin-based cytoskeleton via their action on actin-regulating proteins, endocytic vesicle-mediated protein trafficking, and adhesion protein complexes. We critically evaluate these findings and provide a hypothetical framework that regulates these events.
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Adjudin, a potential male contraceptive, exerts its effects locally in the Seminiferous Epithelium of mammalian testes
Reproduction (Cambridge England), 2011Co-Authors: Ka-wai Mok, Dolores D. Mruk, Pearl P.y. Lie, Wing-yee Lui, C. Y. ChengAbstract:Adjudin is a derivative of 1H-indazole-3-carboxylic acid that was shown to have potent anti-spermatogenic activity in rats rabbits and dogs. It exerts its effects most notably locally in the apical compartment of the Seminiferous Epithelium behind the blood-testis barrier (BTB) by disrupting adhesion of spermatids to the Sertoli cells thereby inducing release of immature spermatids from the Epithelium that leads to infertility. After adjudin is metabolized the remaining spermatogonial stem cells (SSC) and spermatogonia repopulate the Seminiferous Epithelium gradually via spermatogonial self-renewal and differentiation to be followed by meiosis and spermiogenesis and thus fertility rebounds. Recent studies in rats have demonstrated unequivocally that the primary cellular target of adjudin in the testis is the apical ectoplasmic specialization (apical ES) a testis-specific anchoring junction type restricted to the interface between Sertoli cells and elongating spermatids (from step 8-19 spermatids). In this brief review we highlight some of the recent advances and obstacles regarding the possible use of adjudin as a male contraceptive.
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The biology of the desmosome-like junction a versatile anchoring junction and signal transducer in the Seminiferous Epithelium.
International review of cell and molecular biology, 2011Co-Authors: Pearl P.y. Lie, C. Yan Cheng, Dolores D. MrukAbstract:Mammalian spermatogenesis, a complex process that involves the movement of developing germ cells across the Seminiferous Epithelium, entails extensive restructuring of Sertoli–Sertoli and Sertoli–germ cell junctions. Presently, it is not entirely clear how zygotene spermatocytes gain entry into the adluminal compartment of the Seminiferous Epithelium, which is sealed off from the systemic circulation by the Sertoli cell component of the blood–testis barrier, without compromising barrier integrity. To begin to address this question, it is critical that we first have a good understanding of the biology and the regulation of different types of Sertoli–Sertoli and Sertoli–germ cell junctions in the testis. Supported by recent studies in the field, we discuss how crosstalk between different types of junctions contributes to their restructuring during germ cell movement across the blood–testis barrier. We place special emphasis on the emerging role of desmosome-like junctions as signal transducers during germ cell movement across the Seminiferous Epithelium.
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Polarity proteins and actin regulatory proteins are unlikely partners that regulate cell adhesion in the Seminiferous Epithelium during spermatogenesis.
Histology and histopathology, 2011Co-Authors: C. Yan Cheng, Dolores D. Mruk, Pearl P.y. Lie, Wing-yee Lui, Xiang Xiao, Elissa W.p. Wong, Will M. LeeAbstract:In mammalian testis, spermatogenesis takes place in the Seminiferous Epithelium of the Seminiferous tubule, which is composed of a series of cellular events. These include: (i) spermatogonial stem cell (SSC) renewal via mitosis and differentiation of SSC to spermatogenia, (ii) meiosis, (iii) spermiogenesis, and (iv) spermiation. Throughout these events, developing germ cells remain adhered to the Sertoli cell in the Seminiferous Epithelium amidst extensive cellular, biochemical, molecular and morphological changes to obtain structural support and nourishment. These events are coordinated via signal transduction at the cell-cell interface through cell junctions, illustrating the significance of cell junctions and adhesion in spermatogenesis. Additionally, developing germ cells migrate progressively across the Seminiferous Epithelium from the stem cell niche, which is located in the basal compartment near the basement membrane of the tunica propria adjacent to the interstitium. Recent studies have shown that some apparently unrelated proteins, such as polarity proteins and actin regulatory proteins, are in fact working in concert and synergistically to coordinate the continuous cyclic changes of adhesion at the Sertoli-Sertoli and Sertoli-germ cell interface in the Seminiferous Epithelium during the epithelial cycle of spermatogenesis, such that developing germ cells remain attached to the Sertoli cell in the Epithelium while they alter in cell shape and migrate across the Epithelium. In this review, we highlight the physiological significance of endocytic vesicle-mediated protein trafficking events under the influence of polarity and actin regulatory proteins in conferring cyclic events of cell adhesion and de-adhesion. Furthermore, these recent findings have unraveled some unexpected molecules to be targeted for male contraceptive development, which are also targets of toxicant-induced male reproductive dysfunction.
C. Yan Cheng - One of the best experts on this subject based on the ideXlab platform.
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Regulation of microtubule (MT)-based cytoskeleton in the Seminiferous Epithelium during spermatogenesis.
Seminars in cell & developmental biology, 2016Co-Authors: Elizabeth I. Tang, Dolores D. Mruk, C. Yan ChengAbstract:In rodents and humans, testicular cells, similar to other mammalian cells, are supported by actin-, microtubule (MT)- and intermediate filament-based cytoskeletons. Although the cytoskeletal network of the testis serves an important role in regulating spermatogenesis during the epithelial cycle, most of the published findings in the literature are limited to studies that only visualize these cytoskeletons in the Seminiferous Epithelium. Few focus on the underlying molecular mechanism that regulates their organization in the Epithelium in response to changes in the stages of the epithelial cycle. Functional studies in the last decade have begun to focus on the role of binding proteins that regulate these cytoskeletons, with some interesting findings rapidly emerging in the field. Since the actin- and intermediate filament-based cytoskeletons have been recently reviewed, herein we focus on the MT-based cytoskeleton for two reasons. First, besides serving as a structural support cytoskeleton, MTs are known to serve as the track to support and facilitate the transport of germ cells, such as preleptotene spermatocytes connected in clones and elongating/elongated spermatids during spermiogenesis, across the blood-testis barrier (BTB) and the adluminal compartment, respectively, during spermatogenesis. While these cellular events are crucial to the completion of spermatogenesis, they have been largely ignored in the past. Second, MT-based cytoskeleton is working in concert with the actin-based cytoskeleton to provide structural support for the transport of intracellular organelles across the cell cytosol, such as endosome-based vesicles, and phagosomes, which contain residual bodies detached from spermatids, to maintain the cellular homeostasis in the Seminiferous Epithelium. We critically evaluate some recent published findings herein to support a hypothesis regarding the role of MT in conferring germ cell transport in the Seminiferous Epithelium.
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Germ Cell Transport Across the Seminiferous Epithelium During Spermatogenesis
Physiology (Bethesda Md.), 2014Co-Authors: Xiang Xiao, Dolores D. Mruk, Chris K.c. Wong, C. Yan ChengAbstract:Transport of germ cells across the Seminiferous Epithelium is crucial to spermatogenesis. Its disruption causes infertility. Signaling molecules, such as focal adhesion kinase, c-Yes, c-Src, and intercellular adhesion molecules 1 and 2, are involved in these events by regulating actin-based cytoskeleton via their action on actin-regulating proteins, endocytic vesicle-mediated protein trafficking, and adhesion protein complexes. We critically evaluate these findings and provide a hypothetical framework that regulates these events.
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The biology of the desmosome-like junction a versatile anchoring junction and signal transducer in the Seminiferous Epithelium.
International review of cell and molecular biology, 2011Co-Authors: Pearl P.y. Lie, C. Yan Cheng, Dolores D. MrukAbstract:Mammalian spermatogenesis, a complex process that involves the movement of developing germ cells across the Seminiferous Epithelium, entails extensive restructuring of Sertoli–Sertoli and Sertoli–germ cell junctions. Presently, it is not entirely clear how zygotene spermatocytes gain entry into the adluminal compartment of the Seminiferous Epithelium, which is sealed off from the systemic circulation by the Sertoli cell component of the blood–testis barrier, without compromising barrier integrity. To begin to address this question, it is critical that we first have a good understanding of the biology and the regulation of different types of Sertoli–Sertoli and Sertoli–germ cell junctions in the testis. Supported by recent studies in the field, we discuss how crosstalk between different types of junctions contributes to their restructuring during germ cell movement across the blood–testis barrier. We place special emphasis on the emerging role of desmosome-like junctions as signal transducers during germ cell movement across the Seminiferous Epithelium.
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Polarity proteins and actin regulatory proteins are unlikely partners that regulate cell adhesion in the Seminiferous Epithelium during spermatogenesis.
Histology and histopathology, 2011Co-Authors: C. Yan Cheng, Dolores D. Mruk, Pearl P.y. Lie, Wing-yee Lui, Xiang Xiao, Elissa W.p. Wong, Will M. LeeAbstract:In mammalian testis, spermatogenesis takes place in the Seminiferous Epithelium of the Seminiferous tubule, which is composed of a series of cellular events. These include: (i) spermatogonial stem cell (SSC) renewal via mitosis and differentiation of SSC to spermatogenia, (ii) meiosis, (iii) spermiogenesis, and (iv) spermiation. Throughout these events, developing germ cells remain adhered to the Sertoli cell in the Seminiferous Epithelium amidst extensive cellular, biochemical, molecular and morphological changes to obtain structural support and nourishment. These events are coordinated via signal transduction at the cell-cell interface through cell junctions, illustrating the significance of cell junctions and adhesion in spermatogenesis. Additionally, developing germ cells migrate progressively across the Seminiferous Epithelium from the stem cell niche, which is located in the basal compartment near the basement membrane of the tunica propria adjacent to the interstitium. Recent studies have shown that some apparently unrelated proteins, such as polarity proteins and actin regulatory proteins, are in fact working in concert and synergistically to coordinate the continuous cyclic changes of adhesion at the Sertoli-Sertoli and Sertoli-germ cell interface in the Seminiferous Epithelium during the epithelial cycle of spermatogenesis, such that developing germ cells remain attached to the Sertoli cell in the Epithelium while they alter in cell shape and migrate across the Epithelium. In this review, we highlight the physiological significance of endocytic vesicle-mediated protein trafficking events under the influence of polarity and actin regulatory proteins in conferring cyclic events of cell adhesion and de-adhesion. Furthermore, these recent findings have unraveled some unexpected molecules to be targeted for male contraceptive development, which are also targets of toxicant-induced male reproductive dysfunction.
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Regulation of Spermatogenesis in the Microenvironment of the Seminiferous Epithelium: New Insights and Advances
Molecular and Cellular Endocrinology, 2009Co-Authors: C. Yan Cheng, Elissa W.p. Wong, Helen H.n. Yan, Dolores D. MrukAbstract:Abstract Spermatogenesis is a complex biochemical event, involving the participation of the hypothalamus and the pituitary gland via secretion of the hypothalamus hormone GnRH, and two pituitary hormones FSH and LH. Thus, the hypothalamic–pituitary–testicular axis is a crucial regulatory axis for testicular function. Recent studies have shown that in the microenvironment of the Seminiferous Epithelium, wherein each Sertoli cell supports ∼30–50 germ cells at different stages of development, locally produced autocrine and paracrine factors are also involved in spermatogenesis, in particular at the level of cell junctions. These cell junctions at the Sertoli–Sertoli and Sertoli–germ cell interface are crucial for coordinating different events of spermatogenesis by sending signals back-and-forth between Sertoli and germ cells, in order to precisely regulate spermatogonial cell renewal by mitosis, cell cycle progression, meiosis, spermiogenesis, germ cell movement across the Epithelium, spermiation and germ cell apoptosis. In this minireview, we provide an update on these latest findings for an emerging new concept regarding the presence of a local “apical ectoplasmic specialization–blood–testis barrier–hemidesmosome/basement membrane” functional axis that regulates the events of spermiation and blood–testis barrier (BTB) restructuring via paracrine/autocrine factors and polarity proteins produced locally in the Seminiferous Epithelium. These findings provide a new window of research for investigators in the field to tackle the functional regulation of spermatogenesis.
Masamichi Kurohmaru - One of the best experts on this subject based on the ideXlab platform.
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Postnatal testicular development and actin appearance in the Seminiferous Epithelium of the Habu, Trimeresurus flavoviridis.
Anatomia histologia embryologia, 2020Co-Authors: Masamichi Kurohmaru, Toshiyasu Matsui, Hitomi Igarashi, Shosaku Hattori, Yoshihiro HayashiAbstract:The postnatal testicular development and actin distribution in the Seminiferous Epithelium were examined by light microscopy, using the testes of the Habu (Trimeresurus flavoviridis; snake) from 0-year-old to 3-year-old. At 0-year-old (about 1 month after birth), the testis was quite small in size, and the Seminiferous Epithelium was composed of only Sertoli cells and large spermatogonia. Actin immunoreactivity was observed in the peritubular myoid cells, but could not be detected in the Seminiferous Epithelium. At 1-year-old (about 10 months after birth), the testicular size increased to a great degree. In the Seminiferous Epithelium, spermatocytes newly appeared. Actin could still not be detected in the Seminiferous Epithelium. At 2-year-old (about 1 year and 10 months after birth), the testes continued to develop in size. In the Seminiferous Epithelium, elongate spermatids and round spermatids were frequently seen, in addition to Sertoli cells, spermatogonia and spermatocytes. Thus, active spermatogenesis was clearly recognized at this age. Moreover, the actin distribution in the Seminiferous Epithelium was observed at the site between Sertoli cells and spermatids, as well as that at adult stage. The immunoreactivity of actin in the peritubular myoid cells gradually increased from 0-year-old to 2-year-old. Conclusively, it seems likely that spermatogenesis in the Habu initiates at 2-year-old, accompanying with the appearance of actin in the Seminiferous Epithelium.
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distribution of actin filaments in the Seminiferous Epithelium of the habu trimeresurus flavoviridis
Anatomia Histologia Embryologia, 2019Co-Authors: Masamichi Kurohmaru, Toshiyasu Matsui, Hitomi Igarashi, Shosaku Hattori, Yoshihiro HayashiAbstract:: The distribution of actin filaments was examined in the Seminiferous Epithelium of the Habu (Trimeresurus flavoviridis; snake), by transmission electron microscopy and fluorescence histochemistry. By transmission electron microscopy, actin filaments were clearly found only at the site between Sertoli cell and spermatid without a lattice-like structure. Fluorescence histochemistry showed a weak labelling of actin filaments in the Seminiferous Epithelium, whereas these findings seem to be common among reptiles, they are different from those in mammals. Additionally, the bundles of actin filaments adjacent to the plasma membrane of Sertoli cells, appeared in other reptiles, were not observed in the Habu.
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Cycle of the Seminiferous Epithelium in the Java fruit bat (Pteropus vampyrus) and the Japanese lesser horseshoe bat (Rhinolophus cornutus).
The Journal of veterinary medical science, 2001Co-Authors: Takashi Morigaki, Masamichi Kurohmaru, Eiichi Hondo, Junzo Yamada, Srihadi Agungpriyono, Yoshiakira Kanai, Mitsuru Mukohyama, Yoshihiro HayashiAbstract:The cycle of the Seminiferous Epithelium in the Java fruit bat, Pteropus vampyrus, and the Japanese lesser horseshoe bat, Rhinolophus cornutus, was investigated by light microscopy and the characteristics of spermiogenesis were compared between these two species. In the Java fruit bat, the cycle of the Seminiferous Epithelium was divided into 11 stages and developing spermatids were subdivided into 13 steps. While in the Japanese lesser horseshoe bat, the cycle of the Seminiferous Epithelium was divided into 10 stages and developing spermatids were subdivided into 13 steps. Excepting slight morphological differences, the characteristics of acrosomal formation in both species were almost similar with each other. In the Java fruit bat after stage VII, the acrosome gradually elongated, flattened and finally became scoop-like in shape. In the Japanese lesser horseshoe bat after stage VIII, the acrosome elongated, flattened and then slightly shortened. Before spermiation, the acrosome became long spatula-like in shape. The elongation and flattening of spermatids in these two species were similar to those in insectivores. The finding may reflect the fact that the order Chiroptera is phylogenetically close to the order Insectivora.
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The cycle of the Seminiferous Epithelium in the greater Japanese shrew mole, Urotrichus talpoides.
The Journal of veterinary medical science, 2001Co-Authors: Takuo Mizukami, Masamichi Kurohmaru, Yoshihiro Hayashi, Sachi Kuwahara, Masako Ohmura, Yasuko Iinuma, June Izumikubo, Mio Hagiwara, Takao NishidaAbstract:Spermatogenesis and acrosomal formation in the greater Japanese shrew mole, Urotrichus talpoides, were studied by light microscopy. On the basis of acrosomal changes, morphology of spermatid head, nuclear shape, appearance of meiotic figures, location of spermatid and period of spermiation, the cycle of the Seminiferous Epithelium was classified into 12 stages, and developing spermatids could be divided into 15 steps. The mean relative frequencies of stages from I to XII were 10.9, 8.7, 9.8, 7.3, 8.5, 10.3, 12.5, 8.7, 5.8, 5.4, 5.1 and 7.1%, respectively. Similar to the case in the musk shrew, the spermatid nucleus of the greater Japanese shrew mole remained in the middle region of the Seminiferous Epithelium and only the acrosome extended towards the basement membrane. The elongation of the acrosome, however, was not prominent. The proacrosomal vesicle first appeared in stage II and then one large and round granule was seen in stage III. The acrosomal vesicle became flattened on the surface of the nucleus in stage IV. Spreading of the acrosomic system has been recognized from stage VII. In stage VII, spermiation occurred. In stage IX, the spermatid nucleus began to elongate. Elongation and condensation of the nucleus were clearly observed in stage X. In stage XII, pachytene spermatocytes divided into diplotene spermatocytes. In stage XII, meiotic figures and secondary spermatocytes were observed.
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histological study of the Seminiferous Epithelium in the japanese rat snake elaphe climacophora identification of spermatogonium
Journal of Veterinary Medical Science, 1997Co-Authors: Eiichi Hondo, Masamichi Kurohmaru, Yoshihiro Hayashi, Nobuo Kitamura, Michihisa Toriba, Junzo YamadaAbstract:To clarify the features of the Seminiferous Epithelium of the Japanese rat snake, Elaphe climacophora, the identification of spermatogonium and the examination of features of cell to cell junctions were performed in the present study. As for the identification, 5-bromo-2-deoxyuridine (BrdU) incorporation was examined immunohistochemically to mark spermatogonia. The Seminiferous Epithelium was observed throughout a year at the electron microscopic level. BrdU immunoreactivity was detected not only in the cells of the first layer of the Seminiferous Epithelium but also in the second and/or third layers. The cells immunoreactive in the first layer did not seem to attach to the basement membrane and were recognized throughout a year. To investigate cell to cell junctions, we performed actin filament detection by phalloidin staining. Distribution of actin filaments was different from that in mammalian species. At the ultrastructural level, Sertoli-Sertoli cell junctions were observed. Sertoli cells formed junctional complexes. Tight junctions were clearly found, but lacked the backing by actin filaments. These results indicate that the blood-testis barrier of the Japanese rat snakes was structurally different from that of mammalian species. In conclusion, the Seminiferous Epithelium of the Japanese rat snake is intermediate in morphology between amphibians and mammals.
Michael D. Griswold - One of the best experts on this subject based on the ideXlab platform.
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The Cycle of the Seminiferous Epithelium
Encyclopedia of Reproduction, 2018Co-Authors: Michael D. GriswoldAbstract:The formation of spermatozoa in the testes of mammals is a highly spatially and temporally organized process. In order for the constant release of spermatozoa to occur in the testis the entry into the process (spermatogenesis) is continuously initiated and multiple layers of germ cells result. Defined cell types are found in these layers in repetitious association and define the cycle of the Seminiferous Epithelium.
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CYP26 Enzymes Are Necessary Within the Postnatal Seminiferous Epithelium for Normal Murine Spermatogenesis
Biology of reproduction, 2015Co-Authors: Cathryn A. Hogarth, Elizabeth Evans, Jennifer Onken, Travis Kent, Debra Mitchell, Martin Petkovich, Michael D. GriswoldAbstract:The active metabolite of vitamin A, retinoic acid (RA), is known to be essential for spermatogenesis. Changes to RA levels within the Seminiferous Epithelium can alter the development of male germ cells, including blocking their differentiation completely. Excess RA has been shown to cause germ cell death in both neonatal and adult animals, yet the cells capable of degrading RA within the testis have yet to be investigated. One previous study alluded to a requirement for one of the RA degrading enzymes, CYP26B1, in Sertoli cells but no data exist to determine whether germ cells possess the ability to degrade RA. To bridge this gap, the roles of CYP26A1 and CYP26B1 within the Seminiferous Epithelium were investigated by creating single and dual conditional knockouts of these enzymes in either Sertoli or germ cells. Analysis of these knockout models revealed that deletion of both Cyp26a1 and Cyp26b1 in either cell type resulted in increased vacuolization within the Seminiferous tubules, delayed spermatid release, and an increase in the number of STRA8-positive spermatogonia, but spermatozoa were still produced and the animals were found to be fertile. However, elimination of CYP26B1 activity within both germ and Sertoli cells resulted in severe male subfertility, with a loss of advanced germ cells from the Seminiferous Epithelium. These data indicate that CYP26 activity within either Sertoli or germ cells is essential for the normal progression of spermatogenesis and that its loss can result in reduced male fertility.
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Expression of prohibitin in rat Seminiferous Epithelium.
Biology of reproduction, 1993Co-Authors: N M Choongkittaworn, Kwan Hee Kim, D B Danner, Michael D. GriswoldAbstract:Subtractive hybridization was used to isolate cDNAs highly expressed in stages IX-XI of the cycle of the Seminiferous Epithelium in the rat. One of the cloned cDNAs was sequenced and shown to be homologous to a previously described cDNA encoding rat prohibitin. Northern blot analyses showed that 1.9- and 1.2-kb transcripts were present in Sertoli cells whereas 1.5-, 1.2-, and 0.7-kb transcripts were expressed in germ cells. Western blot analyses with anti-peptide antibody to prohibitin revealed only a single 30-kDa protein in testis. Immunocytochemistry demonstrated that prohibitin protein was expressed constitutively in adult Leydig cells and Sertoli cells at all stages. Immunoreactivity of prohibition was very low in preleptotene spermatocytes, very high in leptotene spermatocytes, and very low in zygotene spermatocytes. In pachytene spermatocytes, immunoreactivity was very high in stages VII-XI and was minimal during stages XII and XIV. No protein was detected in spermatogonia and spermatocytes undergoing mitotic and meiotic divisions, respectively. These studies show that the prohibitin gene is expressed differentially in testis. The expression pattern of the prohibitin gene in rat testis appears to correlate with a proposed antiproliferative role of prohibitin.
Sergio Luis Pinto Da Matta - One of the best experts on this subject based on the ideXlab platform.
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Duration of the Seminiferous Epithelium cycle in the frugivorous bat Artibeus lituratus
Theriogenology, 2019Co-Authors: Soraia Fonseca Marinho Da Silva, Sergio Luis Pinto Da Matta, Maria Eduarda De Lima Vieira, Mariella B. Freitas, Danielle Barbosa MoraisAbstract:Abstract The Seminiferous Epithelium goes through multiple changes which enables the differentiation of a spermatogonia in a fully mature spermatozoon. The timing of these changes is species-specific and influences the duration of the reproductive cycles. Bats are among wild mammals whose coordination between male and female reproductive cycles are imperative, since most females show seasonal preferences, even in the Tropics. This seasonal variation demands constant sperm production ready for spermiation in order to guarantee its genetic dispersion and reproduction success. Despite their abundance, little is known about the duration of reproductive cycles in Neotropical bat species, a relevant information for the species management and for conservational strategies regarding anthropogenic and climate influences on bats reproduction. In this study, we aimed at characterizing the stages of the Seminiferous Epithelium cycle (SEC) of the fruit bat Artibeus lituratus and to determine its duration based on the immunohistochemical analysis of the bromodeoxyuridine (BrDU) activity. SEC stages were characterized according to the tubular morphology method and the frequency of each stage was estimated. After intratesticular injections of BrDU, the animals were euthanized at different times, and the estimation of SEC duration was performed by observing the most advanced germ cells in the Seminiferous Epithelium. The most advanced stained cells after 2 days of BrdU injection were the primary spermatocytes in pachytene, transitioning from stages 1–2 of the SEC. Within 2 days, we found a progression of 30.42% of the SEC, and an entire cycle lasted 6.58 days on average. Considering that 4.5 Seminiferous Epithelium cycles are necessary for the whole spermatogenic processes to be completed, the total length of spermatogenesis in A. lituratus was estimated at 29.61 days. Our findings support a pattern of bimodal seasonal polyestry for this species, with rapid spermatogenic cycles.
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Stages and duration of the Seminiferous Epithelium cycle in the bat Sturnira lilium
Journal of anatomy, 2013Co-Authors: Danielle Barbosa Morais, Mayte Koch Balarini, Tarcizio Antonio Rego De Paula, Mariella B. Freitas, Mirlaine S. Barros, Sergio Luis Pinto Da MattaAbstract:Knowledge of the stages that compose the Seminiferous Epithelium cycle (SEC) and determination of the duration of spermatogenic processes are fundamental for the accurate quantification of the dynamics of spermatogenesis. The aim of this study was to characterize the stages that compose the SEC of the bat Sturnira lilium, including evaluation of the average frequency of each of these stages throughout the year and calculation of the duration of the spermatogenic process. An ultrastructural characterization of the formation of the acrosomal cap was also performed. Testicular fragments were processed for morphological and immunohistochemical analysis as well as ultrastructural analysis using transmission electron microscopy. According to the tubular morphology method, the SEC in S. lilium is divided into eight stages, following the pattern found in other mammals. Primary spermatocytes were found at zygotene in stage 1 of the cycle. There was no variation in frequency of each of the stages over the seasons, with stage 1 being the most frequent, and stage 7 the least frequent. The duration of one Seminiferous Epithelium cycle was 3.45 days, and approximately 15.52 days were required for the development of sperm from spermatogonia. Ultrastructural characterization allowed the formation of the acrosomal cap in round spermatids to be monitored. In conclusion, the stages that compose the SEC in S. lilium are generally similar to those described for other mammals, but the duration of the spermatogenic process is shorter than previously recorded for mammals. The presence of primary spermatocytes at zygotene in stage 1 of the cycle is probably due to the longer duration of this stage.
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The Seminiferous Epithelium cycle and daily spermatic production in the adult maned wolf (Chrysocyon brachyurus, Illiger, 1811)
Micron (Oxford England : 1993), 2006Co-Authors: Viviane Lewicki Bitencourt, Tarcizio Antonio Rego De Paula, Sergio Luis Pinto Da Matta, Claudio Cesar Fonseca, Laércio Dos Anjos Benjamin, Deiler Sampaio CostaAbstract:The duration of the Seminiferous Epithelium cycle was estimated in adult maned wolves (Chrysocyon brachyurus, Illiger, 1811), by applying intratesticular injections with tritiated thymidine. The total duration of the Seminiferous Epithelium cycle in this species was calculated in 8.99 days. So, taking into account that approximately 4.5 cycles of the Seminiferous Epithelium are necessary for the whole spermatogenesis process to complete, the production of spermatozoa from one spermatogonia will take about 40.45 days. The duration of the spermiogenesis was calculated to be 12.3 days. The eight stages of the Seminiferous Epithelium cycle were described by the tubular morphology method, which is based either on the form and position of the spermatid nuclei and the occurrence of meiotic divisions. The values of the relative frequency for the pre-meiotic, meiotic and post-meiotic phases in this species were 3.5, 0.78 and 4.8 days, respectively. The maned wolf produces about 29 million spermatozoa a day for each testis gram, therefore being classified among the species provided with a high spermatogenetic efficiency.
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cycle and duration of the Seminiferous Epithelium in puma puma concolor
Animal Reproduction Science, 2006Co-Authors: Flaviana Lima Guiao Leite, Tarcizio Antonio Rego De Paula, Sergio Luis Pinto Da Matta, Claudio Cesar Fonseca, Marco Tulio David Das Neves, Joao Bosco Goncalves De BarrosAbstract:Abstract Puma or sussuarana ( Puma concolor ) is the second largest feline in the American continent and has an ample latitudinal distribution in very diverse habitats. In relation to its conservation status, the puma is considered an extinction-threatened species. The study of the testis morphology and the spermatogenic process in a species is fundamental for establishing the physiologic patterns that will make possible the selection of the protocols for assisted reproduction. A number of peculiarities associated with the reproductive biology of specific species such as the duration of spermatogenic process can be used to determine the frequency of sperm collection. Nine adult male pumas maintained in captivity were used to determine the relative frequency of stages in the Seminiferous Epithelium cycle. Three of them received intra-testicular injections of 0.1 ml tritiated thymidine to determine the duration of the Seminiferous Epithelium cycle, and were subjected to biopsy 7 days later. The cycle of the Seminiferous Epithelium in puma was didactically described into eight stages by the tubular morphology method. The total duration of one Seminiferous Epithelium cycle in puma was calculated to be 9.89 days, and approximately 44.5 days are required for development of spermatozoon from spermatogonia. The duration of spermiogenesis, prophase and other events of meiosis were 14.08, 15.20 and 1.79 days, respectively. The relative frequency of the pre-meiotic, meiotic and post-meiotic phases were 3.98, 1.79 and 4.12 days, respectively.
