摘要:

AbstractThe main features of the Nematode sperm cell are the absence of a flagellum and of an acrosome. Transition forms have never been described, as in other animal phyla also reaching the aflagellate condition, like Platyhelminths and Arthropods. The absence of the flagellum must be considered as a definitive acquisition in the group. In addition, centrioles have been demonstrated to be lacking in most cases. The absence of the acrosome is the second general feature of the Nematode sperm cell. Among other features, more or less common to the Nematodes, the most important and general is the presence in the cell periphery of spheroidal membranous vesicles, originated from the Golgi complex but not involved in fertilization or in the production of ascaridin granules. These are absent only in the Ascarid Aspiculuris and the Dorylaimiid Xiphinema, both kinds of sperm having a peculiar shape. These granules are possibly involved in cell motility. Some Nematode sperm have proteinaceous crystalline inclusions originated from the rough endoplasmic reticulum, called ascaridin granules, the role of which remains obscure. A third important feature is the absence of a nuclear envelope, characterizing all described Nematode spermatozoa, the only exception being the Enoplid Mesacanthion, which seems to be for this reason the most primitive model in the group. Other features are the reduced number, or total absence of, the chondriome, an amoeboid movement not owing to an actomyosin system and a dense halo of 10‐nm filaments surrounding the perinuclear cytoplasm.In this apparently homogeneous picture, three main evolutionary steps can be recognized. The first one, represented by the primitive Enoploid Mesacanthion, is that of a sperm conserving the nuclear envelope, surrounded by a few mitochondria and many membranous vesicles. The second, the most typical of the group, present in high Enoplida, and in Rhabditida, Strongylida, Ascarida, Spimrida, Trichinellida, is that of roundish, amoeboid spermatozoa devoid of a nuclear envelope but containing mitochondria, membranous vesicles, filaments, microtubules, sometimes centrioles, and sometimes ascaridin granules. The third step is apparently a simplification of the second; in fact, in Tylenchida and Dorylaimiida, the sperm is devoid of membranous vesicles, while in Mononchida and Dioctophymatida it is devoid of mitochondria. Aspiculuris, also devoid of membranous vesicles and having a big mitochondrial derivative, can be assigned to the same level. Nematode sperm evolution does not seem therefore to be a progressive acquisition of new characters, but rather a radiation from an already perfect model of some further simplifications occurring in parallel in most of the order

ISSN:0148-7280    

DOI:10.1002/mrd.1120080402

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

年代:1983

数据来源: WILEY

摘要:

AbstractAn elongate crystalloid inclusion has been noted in the cytoplasmic droplet of cauda epididymal bovine spermatozoa. The crystalloid appears to be composed of an aggregate of parallel 10 nm diameter filamentous elements that are associated laterally with one another. It has a regular cross‐banding pattern that repeats at 13–15‐nm intervals. A purified fraction of detached droplets was prepared by centrifugation of sperm suspensions onto Percoll gradients. The detached droplets also exhibited the crystalline inclusion. The origin and possible functions of this structure are disc

ISSN:0148-7280    

DOI:10.1002/mrd.1120080403

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

年代:1983

数据来源: WILEY

摘要:

AbstractIn order to determine whether metabolizable sugars delayed capacitation of guinea pig spermatozoa, these cells were pre‐incubated in Tyrode's pyruvate lactate glucose medium (T‐PLG) or Tyrode's glucose solution (T‐G). They were then transferred to minimal culture medium containing pyruvate and lactate (MCM‐PL) and the occurrence of acrosomal reactions (AR) was determined by light microscopic observations of wet mount aliquots. The percentage of acrosomal reactions was quantitated in fixed samples and occurrence of a true AR was confirmed by electron microscopy. Activated acrosome‐reacted spermatozoa were observed within 5 min when cells were transferred to MCM‐PL solution, after preincubating them for 60–120 min either in T‐PLG or T‐G media. By 15 min in MCM‐PL the percentage of acrosome‐reacted spermatozoa reached values similar to those obtained in cells pre‐incubated from the beginning in MCM‐PL medium (P>0.05 in both) but significantly different from T‐PLG and T‐G controls (P<0.0005 in both). The acrosomal reaction was external calcium dependent and independent of the Tyrode's media pH ranging from 7.2 to 8.0. The results obtained suggested that capacitation occurred in T‐PLG and that it was not delayed by glucose; the results also suggested that capacitation could occur within a short time with glucose as the only exogenous substrate, but that the acrosome reaction could have been arrested by a glucose metabolite. Data are presented which suggest that intracellular levels of glucose‐6‐phosphate (as 2‐deoxyglucose‐6‐phosphate)could play a key role in the expression of the acrosome reaction in sperm already able to perform it. A new hypothesis is suggested for the development of the fertilizing potential of guinea p

ISSN:0148-7280    

DOI:10.1002/mrd.1120080404

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe spermatozoon of Chiton marginatus is a long uniflagellate cell displaying structural features of “modified sperm.” The nucleus presents a conical shape with a long apical cylindrical extension. The chromatin is homogeneously dense. Scattered inside the condensed nucleus, a few nuclear lacunae are visible. The acrosomal complex is lacking. Some mitochondria are located in a laterofrontal structure side by side with the nucleus. The typical midpiece is absent. The cytoplasm forms a thin layer around the nucleus and the mitochondria. The proximal centriole is in a basal nuclear indent. The distal centriole serves to form the axoneme tail with the usual microtubular pattern.During nuclear maturation, the early spermatid nucleus is spherical and contains fine granular chromatin patches. The nuclear envelope shows a deposit of dense material at the base of the nucleus, forming a semicircular invagination occupied by a flocculent mass. In middle spermatid stage, the chromatin gets organized in filaments, coiled as a hank, attached over the inner surface of the basal thickening of the nuclear envelope. The nucleus starts to elongate anteroposteriorly. At the pointed apical portion of the spermatid, a group of microtubules is observed seeming to impose external pressure to the nucleus giving rise to the long apical nuclear point. The mitochondria have a basal position. Late spermatids have an elongated conical nucleus. The chromatin filaments are further condensed, and lacunae appear inside the nucleus. Some mitochondria migrate to a lateral posit

ISSN:0148-7280    

DOI:10.1002/mrd.1120080405

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe nuclei of mature mammalian spermatozoa contain a highly ordered, lamellar substructure, presumably constituting the nucleoprotein of the haploid chromosomal complement. With a view toward constructing a plausible model of chromatin packing in sperm, we have determined some of the quantitative parameters associated with these “nuclear lamellae” in rat spermatozoa. Epididymal sperm from white, Sprague‐Dawley rats were examined by conventional sectioning methods, freeze fracture of fixed and unfixed specimens, and by whole mount replica techniques. Fixation and glycerolation did not significantly alter nuclear structure as seen by freeze fracture. Numerical data obtained from cross fractures of sperm heads indicate that the number of lamellae are quite constant at 10.4 ± 1.8 and that the linear measure of the lamellae is 7.2 ± 2.3 μm per cross fracture. The total area of cross fracture, assuming an elliptical profile is 2.3 k 0.7 μm2and the thickness of the lamellae is 18.2 ± 3.5 nm with a range of 13.5 to 25.5 nm. An estimate of the total surface area of the nuclear lamellae could be made from measurements of projected nuclear area (from replicas and sections) as 173 ± 15 μm2. From these data and the known amount of DNA in the rat sperm nucleus, a model can be proposed for the organization of the nucleoprotein in these lamellar sheets. It is suggested that the chromatin is arranged in a coiled‐coil configuration closely associated together in a side‐by‐side fashion and continuous in extent. Approximate calculations based on this simple model are within a factor of 2 or 3 of predicting the correct amount of DNA in

ISSN:0148-7280    

DOI:10.1002/mrd.1120080406

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

年代:1983

数据来源: WILEY

摘要:

AbstractStating the probability of pregnancy per cycle as PoPFPv, the product of the probabilities of ovulation, fertilization, and egg viability, the model allows an estimate of PFand PoPvfor a series of cycles with known insemination timing. Such results obtained from a series of donor insemination (AID) compared with those generally admitted in natural reproduction suggest that the lower pregnancy rate in AID (all the lower when the postthaw motility is low) is owing to a lower egg viability. Since the abortion rate does not seem higher, there might be a sizable rate of very early embryonic deaths in AID perhaps even as early as nondeveloping eggs.

ISSN:0148-7280    

DOI:10.1002/mrd.1120080407

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe relative proportion of synthesis of 5S RNA to 5S plus 4S RNA is constant during growth of the mouse oocyte. In conjunction with results of a previous study [Brower et al, 1981], the synthesis of 28S, 18S, 5S, and 4S RNA is coordinate during mouse oocyte growth.

ISSN:0148-7280    

DOI:10.1002/mrd.1120080408

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe species specificity of hybridoma antibodies to sperm surface antigens was studied. A collection of over 50 hybridoma antibodies that bind to the guinea pig sperm surface was tested for binding to mouse, rat, hamster, and human sperm by indirect immunofluorescence. None of the antibodies bind to mouse sperm. rat sperm, or human sperm. All but three of the antibodies also fail to bind to hamster sperm. AH‐30, AH‐31, and AH‐1032, the three antibodies that crossreact with hamster sperm, show a different topographical localization on hamster sperm from that seen on guinea pig sperm. The three antibodies do not precipitate a125I surface‐labeled antigen from hamster sperm extracts. However, from guinea pig sperm extracts, all three antibodies precipitate125I surface‐labeled polypeptides with molecular weights (Mr) of 62,000, 52,000, and 38,000. This result suggests that the crossreacting antibodies may be recognizing different antigens on hamster and guinea

ISSN:0148-7280    

DOI:10.1002/mrd.1120080409

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

年代:1983

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120080401

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

年代:1983

数据来源: WILEY