摘要:

AbstractRecent evidence suggests roles for egg derived hydrogen peroxide (H2O2) and ovoperoxidase (secreted by cortical granules) in both fertilization envelope hardening and the block to polyspermy in sea urchins. Strongylocentrotus purpuratus eggs were found to release H2O2during the cortical reaction at fertilization. Treatment of sperm with equivalent concentrations of H2O2resulted in a rapid loss of sperm fertilizing ability. Attempts were made to induce polyspermy by utilizing ovoperoxidase inhibitors at concentrations known to inhibit fertilization envelope hardening. Eggs fertilized in phenylhydrazine became polyspermic, while 3‐amino‐1,2,4‐triazole‐treated eggs did not. These data suggested that a sperm peroxidase might be involved in preventing polyspermy. This hypothesis was tested by the addition of phenylhydrazine or 3‐amino‐1,2,4‐trizaole to H2O2‐treated sperm. Phenylhydrazine acted to protect sperm fertility from H2O2, while 3‐amino‐1,2,4‐triazole increased the adverse effect of H2O2. Simultaneous addition of both inhibitors to sperm incubated in H2O2gave an intermediate value of sperm fertility. These data indicate that (1) H2O2generated by sea urchin eggs during the cortical reaction at fertilization is used for two separate processes, fertilization envelope hardening and the prevention of polyspermy; (2) ovoperoxidase is probably not involved in preventing polyspermy; and (3) egg‐derived H2O2reacts directly with sperm enzymes to prevent polyspermy. The phenylhydrazine‐sensitive enzyme in the sperm is probably a peroxidase that acts to inactivate sperm, while the 3‐amino‐1,2,4‐triazolesensitive enzyme is probably a catalase which protects sperm from H2O2. This hypothesis is consistent with model experiments on horseradish perox

ISSN:0148-7280    

DOI:10.1002/mrd.1120040502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractFerritin‐conjugated goat IgG binds nonspecifically to rabbit sperm. This restricts use of ferritin‐labeled goat antiglobulins as indirect labels in rabbit sperm antigen localization. Ferritin‐conjugated Protein A does not bind nonspecifically to rabbit sperm and is a satisfactory substitute for indirect (“secondary”) labeling of sperm

ISSN:0148-7280    

DOI:10.1002/mrd.1120040503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractMorphological changes in the ring‐shaped nucleoli of spermatids were observed by electron microscopy during spermiogenesis in the guinea pig. In the early acrosomal phase each nucelolus was composed of a bundule of fibers about 25 nm in diameter and 250 nm in length. In cross section the fibers were seen to be closely packed in hexagonal fashion. From the early maturation phase through maturation of the spermatids the fibers of the nuceloli appeared to be replaced by a fine filamentous structure. As the condensation of chromatin proceeded, the filamentous structure decreased in density, and finally the space of the nucleolus was replaced by a nucleolar vacuol

ISSN:0148-7280    

DOI:10.1002/mrd.1120040504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractcAMP‐dependent protein kinase in the supernatant fraction of the homogenate of sea urchin eggs and embryos obtained by centrifugation at 105,000g was investigated in the present study. In the previous report, the dissociation constant between cAMP‐binding proteins and cAMP changed during the development. This suggests that the nature of cAMP‐dependent protein kinase, which has been well established to be the major cAMP receptor, changes during the development. In the present study, four protein kinases were separated through DEAE‐cellulose column from the supernatant of unfertilized egg homogenate. One of them was cAMP‐dependent protein kinase. The others were cAMP‐independent ones. One among them was phosvitin kinase, and the others were not identified at present. The activity of cAMP‐dependent protein kinase gradually increased during a period from fertilization to the swimming blastula stage. During this period, cleavages occurred at a high rate, and the rate decreased after hatching out. Thus, it is supposed that cAMP‐dependent protein kinase in the supernatant may take a part in the mechanism of cleavage. The activity, however, became very low at the mesenchyme blastula, the gastrula, and the pluteus stages. cAMP‐binding capacity was observed in the sedimentable fraction and the supernatant fraction, respectively, obtained by 105,000g centrifugation at all stages examined. If the structure‐bound cAMP‐binding protein is also cAMP‐dependent protein kinase, it may play different roles in the m

ISSN:0148-7280    

DOI:10.1002/mrd.1120040505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractA system has been developed for inducing a calcium‐dependent acrosome reaction in ram spermatozoa in vitro using the calcium ionophore A23187. The resultant reaction is accompanied by release of the acrosomal enzymes hyaluronidase and acrosin, but there is no release of the cytoplasmic enzyme glucose 6‐phosphate isomerase. In any given cell, the visible acrosome reaction apparently takes place rapidly, but there is a variable delay before the reaction occurs. Under optimum conditions, about 90% of treated spermatozoa show an acrosome reaction within one hour.Preincubation of the spermatozoa with the proteinase inhibitors p‐amino‐benzamidine or p‐nitrophenylguanidinobenzoate allows two stages of the reaction to be distinguished ultrastructurally, a membrane fusion stage followed by a dispersal of the acrosomal matrix. In the presence of the inhibitors, the first stage is delayed but is completed within 1 hour, whereas the second remains largely incomplete.In the presence of calcium, ionophore concentrations which induce an acrosome reaction abolish sperm motility rapidly and completely. However, by adding serum albumin shortly after addition of ionophore, motility can be preserved while the acrosome reaction occurs as usual; the motility pattern observed under these conditions is of the “whip‐lash” or “activated” type.Although the motile ionophore‐treated spermatozoa were unsuccessful at penetrating normal mature sheep oocytes in vitro, they were able to penetrate zona‐free oocytes, after which swelling and decondensation of th

ISSN:0148-7280    

DOI:10.1002/mrd.1120040506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe morphology of testicular mitochondria changes markedly during spermatogenesis from a form normally seen in somatic cells to a “germ cell” form in which the matrix is diffuse and vacuolated and finally to a form with a condensed matrix seen in spermatozoa. Colloidal silica gel gradients and high‐resolution, two‐dimensional gel electrophoresis were used to define the changes in density and polypeptide composition that occur in testicular mitochondria during spermatogenesis. Similar densities were observed for mitochondria isolated from the same bovine or murine tissue, but mitochondria from different tissues usually had different densities. Mitochondria from testis of calf, bull, or sexually mature mouse had densities of 1.06 gm/cm3while liver mitochondria were more dense, having a density of 1.09 gm/cm3. “Somatic‐type” testicular mitochondria from calf and “germ cell‐type” mitochondria from sexually mature mouse or bull had similar densities, 1.06 gm/cm3, while the density of mitochondria from ejaculated spermatozoa differed, ρ = 1.08 gm/cm3. Analysis of polypeptide composition of somatic and germ cell mitochondria from testes of prepuberal and sexually mature animals and from highly enriched populations of pachytene primary spermatocytes and round spermatids revealed a staining pattern of mitochondrial proteins that was markedly constant throughout development with most polypeptides being conserved and a few specific spots changing in abundance. Marked differences were detected, however, when mitochondria from ejaculated spermatozoa were compared with those from testis with many minor and major polypeptides missing and several new polypeptides present a

ISSN:0148-7280    

DOI:10.1002/mrd.1120040507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractTo determine the origin of oocyte maturation inhibitor (OMI), cumulus‐enclosed porcine oocytes from medium follicles were cultured for two days in Medium 199 alone, the low molecular weight (<2,000 daltons) fraction of porcine follicular fluid (pFFL), or extracts of granulosa cells from small (1–2 mm), medium (3–5 mm), and large (6–12mm) antral follicles. Additionally, the cumulus‐oocyte complexes were grown in the presence of the low molecular weight fraction of “conditioned” medium from suspension cultures of medium follicle granulosa cells. The percent maturation in cultures with pFFL was significantly (P<.001) less than control cultures. Similarly, addition of the granulosa cell extracts at a 1/20 dilution resulted in a significant reduction in the percent oocyte maturation as compared with controls. The percent maturation after addition of conditioned medium was similarly reduced (P<.001). These results suggest that the granulosa cells probably synthesize and secrete OMI which inhibits oocyte maturation in vitro. Additionally, it appears that the content of OMI in the granulosa cells decreases as the fol

ISSN:0148-7280    

DOI:10.1002/mrd.1120040508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractOocytes were removed from the follicles of rats at 15 to 31 days of age, and their ability to resume meiosis (“meiotic competence”) in vitro was correlated with their diameter and the stage of follicular development. The majority of oocytes explanted on day 15 did not resume meiosis when placed in culture, but the percentage of competent oocytes increased from 14.1% ± 3.0% on day 20 to 67.6% ± 3.3% on day 26 of age. This ability to resume maturation correlated well (r = 0.98) with the increase in diameter of oocytes and coincided with the development of antral follicles.Hypophysectomy on day 15 of age, but not on day 20, reduced the percentage (P<0.001) and number (P<0.001) of competent oocytes and was accompanied by a reduction in diameter of oocytes. Treatment with PMSG or E2increased the number (P<0.001) and percentage (P<0.001) of competent oocytes. These results suggest that the ability of oocytes to mature in vitro is dependent upon stimulation by gonadotropins and that this action of gonadotropin may be mediated by production of estrogen within the foll

ISSN:0148-7280    

DOI:10.1002/mrd.1120040509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractOocyte‐cumulus complexes and granulosa cells were harvested from small (1–2 mm), medium (3–5 mm), and large (6–12 mm) porcine antral follicles and cultured for 2 and 3 days. The effects of various doses of purified hCG and human FSH on progesterone secretion and monolayer formation were examined. After a 2‐day culture period it was found that FSH was more effective in stimulation of progesterone secretion by cultured oocyte‐cumulus complexes than in granulosa cells harvested from small follicles (P<0.01), whereas hCG was more effective in stimulating progesterone secretion in granulosa cells than in oocytecumulus complexes harvested from large follicles. In contrast, after a 3‐day culture period, granulosa cells secreted more progesterone compared to oocytecumulus complexes under control conditions or in the presence of hCG or FSH. After 3 days both FSH and hCG stimulated progesterone secretion by oocytecumulus complexes and granulosa cells; however, the hormone effect was greater upon granulosa cells than oocyte‐cumulus complexes. After 3 days of culture in the case of both follicular cell types, there was a greater response to FSH in the case of cells harvested from small compared to large follicles. The reverse was true in the case of hCG responsiveness.Monolayer formation ability of oocyte‐cumulus complexes was greater in the case of complexes harvested from small and medium than complexes harvested from large follicles. Addition of hCG to the cultures led to a dose‐dependent decrease in monolayer formation by oocyte‐cumulus complexes harvested from a

ISSN:0148-7280    

DOI:10.1002/mrd.1120040510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120040511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY