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Sperm plasma membrane
About: Sperm plasma membrane is a research topic. Over the lifetime, 1016 publications have been published within this topic receiving 49964 citations.
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TL;DR: The results of this study suggest that lipid phase segregation is an important driving force for the organization of the sperm head plasma membrane into subdomains.
Abstract: In order to extend the static information of immunola belling sulphogalactolipids in fixed boar spermatozoa, a fluorescent sulphogalactolipid analogue, galactose(3sulphate)-β1-1′[( N-lissamine rhodaminyl)-12-aminododecanoyl]-sphingosine, was incorporated into plasma membranes of living spermatozoa and its lateral distribu tion over the sperm head was studied. The fluorescent lipid was enriched in the apical ridge subdomain of freshly ejaculated sperm cells. After sperm binding to the zona pellucida the lipid redistributed to the equatorial segment of the sperm surface. A similar shift occurred during capacitation in vitro with 2 mM CaCl2 or with 4% (w/v) bovine serum albumin. The desulphated derivative galactose-β1-1′[(N-lissamine rhodaminyl)-12-aminododecanoyl]-sphingosine was also incorporated into the plasma membrane of freshly ejaculated sperm cells and clearly stained the apical ridge subdomain and the (pre)-equatorial subdomains of the sperm heads. The desulphogalactolipid analogue showed a slightly faster migration to the equatori al segment of the sperm plasma membrane than did its sulphated counterpart. The measured fluorescence intensity distributions correlated linearly with the spatial probe dis tribution, which was checked by fluorescence lifetime imaging microscopy. The observed migration of the incorporated glycolipids precedes the acrosome reaction and is one of the underlying molecular events likely to be important in the process of sperm capacitation. The results of this study suggest that lipid phase segregation is an important driving force for the organization of the sperm head plasma membrane into subdomains.
120 citations
TL;DR: It is shown that sperm hyperpolarize when external Na+ is replaced by N-methyl-glucamine, and results suggest that increases in cAMP content occurring during capacitation may inhibit ENaCs to produce a requiredhyperpolarization of the sperm membrane.
120 citations
TL;DR: Sperm reactivation experiments were undertaken to examine deleterious effects of freezing upon the flagellar microtubular assembly, and a highly significant correlation between minimum freezing temperature and post-thaw temperature of initial reactivation was detected.
Abstract: Cryoinjury in ram sperm was investigated by direct observation, using cryomicroscopy, to validate model hypotheses of freezing injury in such a specialized cell. Fluorescein diacetate was used to determine when during the freeze-thaw cycle the sperm membrane became permeable. In noncryoprotected sperm plasma membrane, integrity was maintained throughout the cooling and freezing process, but fluorescein leakage occurred during rewarming. The temperature of post-thaw permeabilization varied in relation to the minimum temperature reached during freezing; cells cooled to -10 degrees C retained fluorescence into the post-thaw temperature range of 9-24 degrees C (mean +/- SEM; 13.25 +/- 0.91 degrees C), whereas cells cooled to -20 degrees C lost fluorescence shortly after thawing (mean +/- SEM; 2.62 +/- 0.91 degrees C). Sperm cooled to 5 degrees C, but not frozen, retained fluorescence during rewarming up to 20-30 degrees C. The inclusion of glycerol and egg yolk in the freezing medium significantly and independently increased the post-thaw permeabilization temperature. Maintenance of fluorescence was also correlated with ability to resume motility after thawing. Sperm reactivation experiments were undertaken to examine deleterious effects of freezing upon the flagellar microtubular assembly. No direct evidence for such effects was obtained. Instead, a highly significant correlation between minimum freezing temperature and post-thaw temperature of initial reactivation was detected.
118 citations
TL;DR: In this article, it was suggested that an increase in the permeability of the sperm plasma membrane initiates these changes, and it was further suggested that the protein-protein interaction can explain the formation of the acrosomal process.
118 citations
TL;DR: Sperm immobilization prior to ICSI damages the sperm plasma membrane, this damage is sufficient for thiol-reducing agents to gain access to the sperm nucleus, and PVP possibly interferes with sperm nucleus decondensation.
Abstract: In the present study we investigated the relevance of sperm immobilization prior to intracytoplasmic sperm injection (ICSI) in the fertilization process. Using supravital staining of the spermatozoa with eosin and studying sperm decondensation with 2 mM dithiothreitol (DTT) in conditions imitating sperm handling during ICSI, we demonstrated that immobilization of the spermatozoon by squeezing its tail between the glass pipette and the bottom of the dish damages the sperm plasma membrane. Polyvinylpyrrolidone (PVP), which is usually present in the drop with the spermatozoon to facilitate its handling, was found to impede the access of both eosin and DTT to the sperm nucleus. We conclude that (i) sperm immobilization prior to ICSI damages the sperm plasma membrane, that (ii) this damage is sufficient for thiol-reducing agents to gain access to the sperm nucleus, and finally that (iii) PVP possibly interferes with sperm nucleus decondensation.
117 citations