摘要:

AbstractWe here describe further studies on the action of bonellin on sea‐urchin eggs. Bonellin brings aboutSomeof the changes that are known to occur in the egg upon fertilization. In particular, it appears to cause the increased rate of incorporation of amino acids into proteins, the increase of the voltage noise, and the exocytosis of some of the cortical granules. A comparison with the effect of ammonia is discusse

ISSN:0148-7280    

DOI:10.1002/mrd.1120030402

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe isolated rabbit sperm plasma membrane autoantigen RSA‐1 has been identified as a receptor for the lectin, Ricinus communis I (RCA). Using purified RSA‐1 labeled with125I, the autoantigen was shown to bind to RCA affinity columns and the eluted fraction bound to specific anti‐RSA‐1 alloantiserum immunoadsorbent

ISSN:0148-7280    

DOI:10.1002/mrd.1120030403

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

年代:1980

数据来源: WILEY

摘要:

AbstractIt has been suggested that the production of estrogens by the fetal ovary may modulate the entry or progression of meiosis in the female mammalian fetus. In the present study the possibility that the site of this steroid synthesis is the rete ovarii system was explored in the fetal mouse of gestational ages 12.5 to 18 days. The method of ultracytochemical localization of 3β hydroxy‐steroid ferricyanide was used. Reaction product was found in the cytoplasm of the rete ovarii (prefollicular) cells as early as day 14 with increasing amounts seen at later gestational ages. The presence of this essential enzyme system in cells closely applied to oogonia and oocytes during an active meiotic period must be considered in developing concepts of meiotic ent

ISSN:0148-7280    

DOI:10.1002/mrd.1120030404

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

年代:1980

数据来源: WILEY

摘要:

AbstractRegional differences in the structure of the plasma membrane and acrosome membrane of squid spermatozoa were studied by freeze‐fracture and thin section electron microscopy. In regions of close apposition the plasma membrane and acrosome membrane are adjoined to one another by regularly spaced linkages. These linkage sites, overlie a set of fibers located at the inner face of the acrosomal membrane. The acrosomal fibers terminate in a layer of granular material located at the base of the acrosome. Detergent treatment of sperm releases the fibers and granular material as an interconnected complex. Freeze‐fracture replicas reveal a random arrangement of intramembranous particles in the plasma membrane over the sperm head and linear aggregates of intramembranous particles in the acrosomal membrane. Several regional differences in the structure of the flagellar plasma membrane are present. The thickness of the glycocalyx is progressively reduced distally along the flagellum. Freeze‐fracture replicas show evenly spaced linear arrays of intramembranous particles which extend parallel t o the flagellar long axis. Examination of spermatozoa extracted to disrupt flagellar geometry suggest that the dense fiber‐doublet microtubule complexes are attached to the plasma membrane. The possible functional role of these membrane differentiations and their relationship t o membrane structures in mammalian spermatozoa are di

ISSN:0148-7280    

DOI:10.1002/mrd.1120030405

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

年代:1980

数据来源: WILEY

摘要:

AbstractIntial in vivo studies were performed to observe the proportion of eggs fertillized at specific intervals after natural mating and ovulation in our research mouse colony. Proestrous females of the C57BL/10Wt, SJL/Wt inbred strains and the F1hybrid cross (B10 × SJL or reciprocals) were paired in the after‐noon with males of their respective strain and examined for vaginal plugs at the midpoint of the dark period (2400 hours). Oviducts were periodically collected from mated females, and ovulation was first observed at 4, 5.2, and 3 hours after 2400 hours in the B10, SJL, and F1hyrid, respectively. The clutch of eggs from each ovulating female, was placed in culture, and cleavage oviduct lavage verifying female mating was placed in culture, and cleavage was used as the criterion for fertilizaition. Fifty percent of the eggs were fertilized 2.2, 5.0, and 2.5 hours after ovulation in B10, SJL, and F1hybrid females, respectively. Because twice the legth of time was required to fertilize a similar proportion of eggs from the SJL strain as the F1hybrid, these two strains were used for determining their rate of fertilization under more fully controlled conditions in vitro. Forty‐nine percent of F1hybrid eggs were fertilized after 4 hours incubation with SJL epididymal sperm, whereas 53% fo SJL and 56% of F1hybrid eggs were fertilized after only 2 hours incubation with F1hybrid epididymal sperm. Thus, using sperm from these two mouse strains, the amount of time required to fertilize approximately 50% of the eggs within a clutch both in vivo and vitro was very similar. These observations demonstrte teh validity of using this in vitro system for fertilization studies and confirm that the temporal events in sperm capacitation and egg penetration are dependent on the genotype of the sperm. Similarities in fertilization rates at specific times after ovulation or insemination in vitro imply that the initiationof sperm capacitation in vivo occurs near the time of ovulation and several hours after mating. We tentatively suggest that follicular fluid may be required for completion of mouse sperm capacitaiton in

ISSN:0148-7280    

DOI:10.1002/mrd.1120030406

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

年代:1980

数据来源: WILEY

摘要:

AbstractSpermatozoa of six species of Australian marsupials have been studied. The nucleus is highly unstable when compared with those of eutherian mammals. When thin films of spermatozoa in buffered saline are air‐dried on glass slides, the nucleus disintegrates and flattens, leaving the acrosome, midpiece, and tail intact. This spreading of the nucleus can be inhibited by seminal plasma proteins and by bovine serum albumin, but is potentiated by detergents. The nucleus also decondenses spontaneously in the presence of high concentrations (>0.25M) of calcium and magnesium salts, leaving the head membranes, acrosome, midpiece, and tail intact. This is inhibited by EDTA. In some species, certain areas of the nucleus appear more resistant t o Ca++/Mg++treatment, and the initial stages of decondensation are uneven. Ultrastructurally the Ca++/Mg++dispersed chromatin shows a moderately fine, branching, fibrillar structure, interspersed with dense granules. Treatment with disulphide bond cleaving agents together with detergents results in rapid and complete dispersal of the chromatin and acrosome, and slow digestion of midpiece and tail structures. Treatment with HCl, NaCl, KCl, EDTA, detergents, and sucrose has no effect on nuclear integrity, but treatment with NaOH (0.9–1.0M) results in complete digestion of the whole sperm. These findings are discussed in the light of evolutionary differences between marsupial and eutherian mammals in terms of sperm structure and composit

ISSN:0148-7280    

DOI:10.1002/mrd.1120030407

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

年代:1980

数据来源: WILEY

摘要:

AbstractYolk material of preimplanation stages of embryos of the hamster, mouse, and rat were examined by a standardized electron microscopical procedure. The material was encountered as fibrils, scattered more or less densely in the cytoplasm. In the hamster, the material was present in large masses and the fibrils had a chain‐like appearance when cut longitudinally. The ultrastructure of the fibrils was compatible with a helical pattern. The fibrils had a width of about 40 nm and the pitch (the axial distance of the repeating unit) was about 30 nm. In the mouse, the yolk material was dispersed in the cytoplasm forming small plaque‐like groups. Also, in this species the fibrils were chain‐like but smaller than in the hamster. The fibrils were often closely situated, resulting in images with varying crystalline appearances. In the rat, the yolk appeared as light areas occupying a substantial part of the cytoplasm. The fibrils in the yolk plaques were sparse and diffusely outlined. They were thinner than the fibrils of the mouse‐yolk material, did not display any helical pattern at the resolution used, but showed a peri

ISSN:0148-7280    

DOI:10.1002/mrd.1120030408

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

年代:1980

数据来源: WILEY

摘要:

AbstractMorphological and cytochemical (acid phosphatase) changes associated with mouse ova and cumulus cells aged within the oviducts (in vivo) or in culture (in vitro; 1–24 hours postovulation) have been investigated. Structural alterations of cumulus cells were apparent immediately after ovulation and included nuclear pycnosis and cytoplasmic vacuolization. Nevertheless, approximately 30% of the cumulus masses examined contained cells that plated out when cultured and remained viable for up t o three days in vitro. From 12 t o 24 hours postovulation almost all cumulus cells of specimens aged in vivo showed signs of degeneration. Disruption of the meiotic spindle and an increase in acid phosphatase positive organelles were characteristic of in vivo and in vitro aging ova. The percentage of fragmented eggs obtained from super‐ovulated (5 IU PMS followed by 5 IU HCG) mice approximately one and 24 hours postovulation was not significantly different. Eggs obtained from superovulated animals and aged in vitro for 24 hours yielded significantly more fragmented ova. Fragmented eggs were not obtained from cycling females on the morning of estrus. When such eggs were cultured in vitro for 24 hours the percent fragmentation was significantly lower than that for aged eggs obtained from super‐ovulated mice. These results indicate that 1) similar morphological alterations occur among cumulus cells and eggs aged either in vitro or in vivo, 2) ova from superovulated mice do not constitute a homogeneous population and 3) the method of superovulation employed in this study induces the ovulation of a relatively large group of eggs that are susceptible to fragmentation when cultured in

ISSN:0148-7280    

DOI:10.1002/mrd.1120030409

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

年代:1980

数据来源: WILEY

摘要:

AbstractAn investigation was made as to the nature of two of the factors, termed S1, released within the first 30 minutes after contact is made between capacitated hamster sperm and the zona pellucida in vitro. Previous studies showed that these S1 factors were detected two and 20 to 25 minutes after the gametes were combined and that, based on filtration studies, the former possessed a molecular weight of less than 5,000 daltons. The present results show that the quantity of the 20–25‐minute S1 factor released into the supernatant increased linearly as a function of the sperm concentration. This factor passed unimpeded through a filter with a 5,000 molecular weight cutoff but only 42% of the activity traversed a filter with a cutoff of 2,000 daltons. The two‐minute S1 factor, in the virtual total absence of cells, was stable for 10 to 15 minutes, but lost significant activity upon longer incubation. Under the same conditions, the 20–25‐minute factor lost approximately 25% of its activity within 15 minutes, but remained stable at this level for at least 45 minutes of incubation. Both S1 factors were not affected by a mixture of glycosidases, but were inactivated by subtilisin, trypsin, and leucine aminopeptidase which was contaminated with endopeptidases. The activity of the two‐minute S1 factor appeared more susceptible to the action of the proteases than that of the 20–25‐minute S1 factor. In contrast to previous results obtained with the two‐minute S1 factor, the release of the 20–25‐minute S1 factor was not inhibited by the inclusion of soybean trypsin inhibitor a t concentrations which are known to inhibit penetration of the zona by the sperm. The results suggest that the two‐ and 20–25‐minute S1 factors are pepti

ISSN:0148-7280    

DOI:10.1002/mrd.1120030410

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

年代:1980

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120030411

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

年代:1980

数据来源: WILEY