摘要:

AbstractUsing a semi‐chemically defined medium, the requirement of extracellular Ca2+for survival, capacitation, and acrosome reaction of spermatozoa as well as various stages of fertilization in the hamster was studied. A Ca2+‐deficient environment is unfavorable for long‐term survival of spermatozoa. Sperm capacitation may occur in Ca2+‐deficient media, but not as efficiently as in normal media. The acrosome reaction definitely requires extracellular Ca2+. Other processes or phenomena that require extracellular Ca2+are initiation and maintenance of hyperactivated motility of spermatozoa, penetration of acrosome‐reacted spermatozoa into the zona pellucida, fusion of the spermatozoa with eggs, and the development of pronuclear eggs into two‐cell embryos. Extracellular Ca2+is apparently unnecessary for the attachment of spermatozoa to the zona and egg surfaces, decondensation of the sperm nucleus, and the development of sperm and egg pronuclei within the egg. These results were compared with data obtained in other species such as the sea urchin, mouse, rat and

ISSN:0148-7280    

DOI:10.1002/mrd.1120050404

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe influence of chromosome variability on the production of euploid spermatozoa was investigated in a suitable biological model, the Akodon molinae system. This consists of individuals whose chromosome constitution is 2n = 42, 2n = 43, or 2n = 44. The only difference between these three karyotypes occurs through a Robertsonian rearrangement combined with two pericentric inversions. Thus, the animals with 2n = 42 (simple homozygotes or SH) have two large metacentric chromosomes number 1; animals with 2n = 43 (heterozygotes or Ht) have a chromosome 1 and two subterminal chromosomes la and lb homologues of the long and short arms of the chromosome 1, respectively; animals with 2n = 44 (double homozygotes or DH) have a pair of la and a pair of lb chromosomes. The gametic euploidy frequency correlated with each chromosome constitution was evaluated on the basis of the DNA content of spermatozoa, which was determined microdensitometrically after the Feulgen reaction, taking into account the site of the spermatozoa along the male genital tract. A comparative assessment of gametic aneuploidy frequency in caput epididymis versus vas deferens demonstrated (1) a falloff in euploid production in passing from the 2n = 42 to the 2n = 44 chromosome forms, alongside a high degree of intragroup variability, and (2) a lower aneuploidy frequency in the vas deferens than in caput epididymis in all the forms considered. These two features, taken together with similar results in the mouse chromosome variability system, suggest that a selection mechanism is operative against aneuploid spermatozoa in the epididymis. This finding is of interest in a wider perspective, since it might turn out to be valid for many mammals.

ISSN:0148-7280    

DOI:10.1002/mrd.1120050405

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

年代:1982

数据来源: WILEY

摘要:

AbstractExperiments were designed to test the effects of simple sugars and complex polysaccharides on the attachment of mammalian spermatozoa with the zona pellucida. In the guinea pig, L‐fucose was a twofold better inhibitor of the attachment compared to other sugars at 50 mM. Fucoidin, an algal polysaccharide rich in sulfated L‐fucose, was a very potent inhibitor, completely blocking attachment at a concentration of 100 μg/ml. Several other highly sulfated glycosaminoglycans showed no inhibitory activity, suggesting the fucoidin effect was not simply due to its charge or sulfate. In addition, fragments of fucoidin, generated by partial hydrolysis and isolated using Biogel P‐2, were nearly as inhibitory as the native molecule on a weight basis. Fucoidin also inhibited sperm‐zona attachment in the hamster and human; thus, its effect is not species specific. The data suggest that L‐fucose may be part of a recognition signal between mammali

ISSN:0148-7280    

DOI:10.1002/mrd.1120050406

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe bioelectric responses at fertilization of the sea urchin Lytechinus variegatus are a complex series of membrane potential and resistance changes that occur concomitant with gamete fusion, ionic fluxes, and the cortical granule discharge. This work attempts to separate the electrical effects of sperm‐egg interactions from those of the cortical reactions. Two approaches were taken to discern the electrical events associated with insemination, distinct from cortical granule discharge: (1) fertilization of eggs treated with 3% urethane, 10 mM procaine, or 10 mM nicotine, to prevent the cortical reaction and (2) refertilization of fertilized eggs (denuded with 1 mM aminotriazole containing 1 mg/ml soybean trypsin inhibitor). Cortical granule discharge in the absence of sperm incorporation was investigated by artificial activation with 5 μM A23187 or by fertilization in the presence of 10 μM cytochalasin D, which prevents incorporation.These results are consistent with a model in which the sperm‐egg interaction triggers both a rapid (50–400 msec), but minor (≅10 mV), electrical transient that leads to an action potential and then both the Na+‐dependent fast block to polyspermy and the late block resulting from the secretion of the cortic

ISSN:0148-7280    

DOI:10.1002/mrd.1120050407

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

年代:1982

数据来源: WILEY

摘要:

AbstractCircular DNA molecules were isolated from human and boar whole spermatozoa or spermatozoal nuclei and measured for size by electron microscopy. The DNA molecules derived from both mammals were heterogeneous in size ranging from 0.07 to 17 μm; nearly 75% of the molecules were ⩽0.5 μm in length. The mean lengths were 1.0 μm and 1.5 μm for circular DNAs isolated from human and boar spermatozoa, respectively. The origin and function of these molecules remains un

ISSN:0148-7280    

DOI:10.1002/mrd.1120050408

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

年代:1982

数据来源: WILEY

摘要:

AbstractRecent claims that bull sperm display chemotaxis to synthetic peptides known to be chemotactically active for neutrophils are not based on direct observation of sperm behavior. When these observations are made, no change in sperm motility or direction is seen. The supposed chemoattractant effect is probably based on disruption by the peptides of the sperm acrosome, resulting in increased sperm adhesion to the glass surface inside the pipette containing the supposed chemoattractive peptide.

ISSN:0148-7280    

DOI:10.1002/mrd.1120050409

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

年代:1982

数据来源: WILEY

摘要:

AbstractTo assess the ability of ram spermatozoa to bind to oocytes, spermatozoa (2.5–200 × 106/500μ1) taken from the rete testis, or from various regions of the epididymis (head, body, and tail) were mixed with cumulus‐free heterologous oocytes obtained from immature superovulated rats. After incubation for 30–45 min in Parker 199 Hepes medium at 35°C, testicular spermatozoa were unable to bind to the zona at any of the concentrations used. However, spermatozoa from the middle body of the epididymus were able to bind to the zona and this binding reached a maximum in the distal body and in the tail of the epididymis. The spermatozoa were bound by their heads. Electron microscopy showed that the plasma membrane and the acrosome of the bound sperm remained intact, without any sign of an acrosome

ISSN:0148-7280    

DOI:10.1002/mrd.1120050410

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

年代:1982

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120050403

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

年代:1982

数据来源: WILEY