摘要:

AbstractRhynchocinetes typus spermatozoa obtained from the vas deferens have the shape of a round‐headed nail. The head measures 30 μm in diameter and 14 μm of height. At the center of the flat face of the head emerges a single rigid spike of 53 μm in length. Cross sections of this spike show that it has a wall of 0.4 μm in thickness and a core of 0.6 to 0.8 μm. The outer surface of the spike has a longitudinal striation. When the spermatozoa are placed in sea water it is possible to observe the unfolding of rays. The number of rays in different spermatozoa of the same individual varies from 9 to 13. Each ray is formed by a channel‐like sheath that contains a rigid rod that occupies about 1/3 the length of the ray. This rod has a transverse striation with a periodicity of 185A. The rays are bound among them by a thin membranous sheet that is highly folded in vas deferens spermatozoa. At the distal end of each ray there is a rigid spine of 50 μm in length. The nucleus is coplanar to the radial plane and it extends through the rays. The structure and ultrastructure of R typus spermatozoa depart from that reported for spermatozoa of other Caride

ISSN:0148-7280    

DOI:10.1002/mrd.1120070102

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

年代:1983

数据来源: WILEY

摘要:

AbstractSpermiogenesis of the eupyrene sperm in the snail, Fusitriton oregonensis, was studied with light and electron microscopes. Endoplasmic reticulum, which encircles the nucleus in each spermatid, appears to connect with the Golgi body and to interconnect between adjacent spermatids via cytoplasmic bridges. It is suggested that as the Golgi body migrates around the nucleus the endoplasmic reticulum may circulate with it. The alignment of the proacrosome with the nucleus is effected by a 180° rotation of the Golgi body, after which it separates and migrates posteriorly with the residual cytoplasm. Each sperm possesses a well‐developed intracellular digestive system as indicated by multivesicular bodies, residual bodies, and myeloid figures. Autophagy begins in the residual cytoplasm before it is released from the middle piece. Microtubules are found outside the nucleus and mitochondria during the final stages of spermiogenesis, when elongation is almost complete. These microtubules appear to be involved in the final shaping and twisting process, in which torsion is locked in the nucleus and the mitochondria spiral around the axoneme. The annulus attaches the distal centriole to the plasma membrane in the early spermatid and as flagellar production begins they move towards the implantation fossa at the base of the nucleus. There are two centrioles in the early spermatid, the distal centriole and procentriole. The small procentriole fuses with the distal centriole in the intranuclear canal to form the centriolar cap of the basal body. This cap is pushed through the end of the nuclear tube and is separated from the subacrosomal space by only the nuclear membran

ISSN:0148-7280    

DOI:10.1002/mrd.1120070103

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

年代:1983

数据来源: WILEY

摘要:

AbstractDevelopmental aspects of the capability to generate an action potential have been studied in mouse oocytes and early embryos, taking the peak level and the rate of rise of the action potential as parameters of cell excitability. We report here that experimentally induced membrane excitability in mouse oocytes appears throughout oogenetic growth, further develops throughout meiotic maturation, does not undergo main changes at fertilization, and slightly decreases throughout early cleavage, at least up to the four‐cell stage of embryonic development. Calcium is involved in the rising phase of action potential throughout oogenesis, maturation, and early embryonic developmen

ISSN:0148-7280    

DOI:10.1002/mrd.1120070104

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

年代:1983

数据来源: WILEY

摘要:

AbstractA procedure using centrifugation in density gradients composed of Percoll was developed for isolation of spermatozoa from mammalian semen. To evaluate the technique, rabbit, human, or bovine semen was layered over continuous Percoll gradients ranging in density from 1.02 to 1.13 gm/ml and centrifuged at 1,500g for 45 min. After centrifugation, the seminal plasma remained above the gradient, whereas the spermatozoa and seminal particles were distributed within the gradient according to their buoyant densities. Unlike most washing techniques, no sperm pellet was formed; instead, the spermatozoa were concentrated into a compact band above the most dense layer of Percoll. The spermatozoa recovered from the gradient were easily resuspended by gentle techniques. Thus, the mechanical stress to the spermatozoa was minimized. Osmotic stress to the spermatozoa was also negligible as the Percoll gradients were isotonic throughout. Spermatozoa obtained by this technique possessed motility equivalent to that of spermatozoa in the unfractionated semen. Sperm suspensions recovered from the gradients contained less than 5% of the nonspermatozoal particles present in the original samples of unfractionated semen. Soluble seminal components were also efficiently removed from the spermatozoa. Thirty billion bovine spermatozoa could be fractionated on a single gradient without loss of effectiveness. Recovery of spermatozoa from these preparative separations averaged 80%. These results demonstrated that Percoll was a superior medium for efficient density gradient isolation of motile spermatozoa free of contamination by other seminal constituents.

ISSN:0148-7280    

DOI:10.1002/mrd.1120070105

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe effects on mouse embryo development in vivo of varying the numbers of spermatozoa used in artificial inseminations was studied. The two criteria used in the evaluation of the progress of embryo development were 1) ability to reach the two‐cell stage and 2) success of development from the two‐cell stage through implantation. A 44% reduction in the yield of two‐cell embryos and a 67% reduction in the number of implants was observed when C3HeB/FeJ females were inseminated with one‐twentieth the number of spermatozoa estimated to be present in a typical ejaculate. The reduction in the yield of two‐cell embryos was substantially reversed by a second insemination of a large number of heat‐inactivated spermatozoa 12 hr after the first insemination. The sperm‐dependent reduction in development from the two‐cell stage through implantation was prevented only by normal viable (unheated) spermatozoa. These results were rationalized by the hypothesis that in female C3HeB/FeJ mice spermatozoa serve physiological functions beyond the fertilization of ova and that spermatozoa may act to foster early embryo development through modulation of the environments embryos experience as they move through the rep

ISSN:0148-7280    

DOI:10.1002/mrd.1120070106

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

年代:1983

数据来源: WILEY

摘要:

AbstractMechanisms were sought through which the control of preimplantation mouse embryo development by spermatozoa might be effected. A potential route for the transmission of sperm‐dependent stimuli to C3HeB/FeJ females was uncovered. It was found that within 24–48 hr after artificial insemination with spermatozoa, in which the DNA had been labeled with tritiated thymidine, a minimum of 9% of the radioactivity was transported across the uterine walls. It was deposited among the maternal tissues in a pattern that differed from the patterns of isotope distribution obtained when either free tritiated thymidine or Escherichia coli cells containing DNA labeled with tritiated thymidine were used instead of labeled sper‐matozoa. In sperm‐treated animals the ovaries, the adrenals, and a mesenteric lymph node exhibited strikingly large accumulations of radioactivity. The heart, spleen, and uterus manifested lesser accumulations of label, but were higher than liver, kidney, lung, brain, muscle, and intestine. The specific activity of the lymph node was found to decrease during the 12–72‐hr period following insemination. This result led to the hypothesis that the lymphatic system could serve as a route for the dissemination, to maternal tissues, of radioactivity originally associated with spermatozoa deposited in the uterus. Heat‐inactivated spermatozoa, which have the potential for facilitating the first cleavage of fertilized embryos, exhibited a distribution pattern indistinguishable from untreated spermatozoa. Sperm protein kinase was found to survive the heat inactivation of spermatozoa. This stability was interpreted as being compatible with the kinase functioning as an intermediary in the transmission of sperm‐dependent stimuli that control preimplantation embryo deve

ISSN:0148-7280    

DOI:10.1002/mrd.1120070107

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.1120070108

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.1120070101

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

年代:1983

数据来源: WILEY