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.

Inhibition of sperm motility does not affect live-dead separation of bull sperm by glass beads.

Abstract: AIM This study was designed to explore factors which influence binding of dead versus live sperm to glass filters. METHODS Multiple semen collections from bulls were used to explore selective filtration of bull sperm as influenced by nonlethal inhibition of sperm motility with fluoride, killing of sperm by quick-freezing, alteration of the glass surface with silicone, and different intervals of sexual rest between semen collections. RESULTS A comparison of glass spheres 100, 200 and 390 microm in diameter indicated that 200 microm spheres were optimal for selective filtration. Quantitative separation of live from dead sperm was demonstrated with a correlation between the percentage of motile sperm and retention of sperm by the filter of r = -0.87 (P < 0.05). Up to 0.02 mol/L NaFl did not alter the proportion of sperm retained by the filter despite inhibiting sperm motility during filtration, an inhibition which was reversible. Proportions of live-dead sperm, based upon eosin staining, were unaffected by fluoride. Coating the glass spheres with silicone greatly reduced selective filtration. Dead sperm adherence to glass was reduced and resistance to NaFl inhibition was increased by daily ejaculation versus one-week intervals of sexual rest. CONCLUSION These studies indicate that the adherence of sperm to glass is primarily due to some form of physico-chemical change accompanying death of the sperm cell independent of active sperm motility. This attraction between the sperm plasma membrane and glass is modified by the age of the ejaculated sperm. This information is useful in evaluating different clinical procedures used for sperm separation.

Sperm Testing and ICSI Selection by Hyaluronic Acid Binding: The Hyaluronic Acid-Coated Glass Slide and Petri Dish in the Andrology and IVF Laboratories

Abstract: It is well established that the testis-expressed HspA2 chaperone is a measure of human sperm cellular maturity and function, including fertilizing potential. The presence of HspA2 in the synaptonemal complex also provides the link between low HspA2 expression and increased frequencies of chromosomal aneuploidies in arrested maturity, dysmature sperm. There is also a relationship between the levels of HspA2 expression in elongated spermatids and the related spermiogenetic events, such as cytoplasmic extrusion, formation of the normal sperm shape, the nuclear events of histone-transition protein-protamine replacement, and the associated changes in DNA packing, as well as the sperm plasma membrane remodeling. The membrane remodeling facilitates the formation of the zona pellucida (and the hyaluronic acid [HA]) binding sites, which enables the sperm to fertilize and provide paternal contribution to the embryo. In dysmature sperm, some or all of these developmental steps are arrested (there is a well-established relationship between nuclear and cytoplasmic dysmaturity). For this reason, the sperm selected by the zona pellucida or by hyaluronic acid are comparable via the common origin of plasma membrane remodeling and the formation of both receptors. With the advent of ICSI, the challenge to understand which sperm is empowered to fertilize the egg and the ongoing research focusing on biochemical markers of sperm function have taken higher prominence, as the pathology in male infertility patients, who require ICSI treatment, of higher complexity. The HA receptor of mature sperm, coupled with HA-coated slides or Petri dishes, allows the direct visual observation of sperm-HA binding, which is the basis for sperm maturity testing, and the assessment of sperm binding to HA which is related to sperm-zona pellucida binding. Sperm-Ha binding provides a major advancement in semen evaluation and it also facilitates; the selection of single mature sperm for ICSI [3]. The HA-binding step, similar to zona pellucida binding, eliminates dysmature sperm that exhibit cytoplasmic retention, persistent histones, and DNA chain breaks. Further, the frequencies of sperm with chromosomal disomy and diploidy are reduced by 4–6-fold in HA-bound sperm vs. semen sperm fractions [3]. This reduction is similar to the increase of chromosomal aberrations in ICSI children. Combined studies of sperm shape and chromosome probes demonstrated that sperm shape does not reliably aid selection of haploid sperm [34]. Thus, HA-mediated sperm selection is a novel and efficient technique that may alleviate potential future public health problems that are related to ICSI with visually selected sperm, such as chromosomal aneuploidies, shortened lifetime, and increased cancer rates.

Fine Structural Changes in the Postacrosomal Region of the Hamster and Mouse Sperm Head at the Initial Stage of Gamete Interaction in vivo

Abstract: This report documents ultrastructural changes in the postacrosomal region of the hamster and mouse sperm head at the initial stage of gamete interaction in vivo. Prominent structures were sequentially visualized: first, the periodic substructure crossbridging the postacrosomal sheath to the overlying plasma membrane, and then the small, electron-dense, granular structures lining the outer surface of the postacrosomal sheath. The periodic substructure became visible at the restricted region where the sperm plasma membrane was just prior to or in the act of detaching from the periodic substructure. The granular substances lined up along the external face of the postacrosomal sheath immediately after the detachment of the sperm plasma membrane, but before the complete degradation of the periodic substructure. These structural changes were completed before sperm nuclear decondensation started. The region where the granular structures were visualized was close to that of the antigen recognized by the monoclonal antibody MN13, which is supposed to be involved in the association of the periodic substructure with the overlying plasma membrane (TOSHIMORI et al., 1991). Based upon these results, we present the progress of events at the initial stage of gamete interaction.

Purification of N-acetyllactosamine-binding Activity from the Porcine Sperm Membrane : Possible Involvement of an ADAM Complex in the Carbohydrate-binding Activity of Sperm

Abstract: Although the importance of carbohydrate recognition by sperm during egg zona pellucida binding has been widely reported, the sperm molecular species that recognize the carbohydrates are poorly characterized. Our previous cytochemical study indicated that two kinds of carbohydrate-binding proteins are expressed on porcine sperm heads-one recognizes N-acetyllactosamine (Galβ1-4GlcNAc-), and the other recognizes the Lewis X structure (Galβ1-4(Fucα1-3)GlcNAc-). For this report, we used proteomic techniques to characterize the sperm proteins that bind N-acetyllactosamine. Porcine sperm plasma membrane was solubilized with a detergent solution and subjected to sequential chromatography with dextran sulfate agarose, affinity, and hydroxyapatite, and the binding activities in the eluates were monitored by a solid-phase binding assay. The tryptic peptides of two proteins most likely associated with the binding activities were subjected to tandem mass spectrometry sequencing. A subsequent database search identified one of the two proteins as predicted disintegrin and metalloprotease domain-containing protein 20-like (XP_003128672). The other protein was identified as disintegrin and metalloprotease domain-containing protein 5 (AB613817) by database searches for homologous amino acid sequences, cDNA cloning, nucleotide sequencing and nucleotide database searches. Furthermore, two-dimensional blue native/SDS-PAGE demonstrated that they formed a variety of non-covalent complexes. Therefore, these ADAM complexes probably are responsible for the N-acetyllactosamine-binding activity. An affinity-purified fraction containing these ADAM complexes showed zona pellucida-binding activity, though the activity was relatively weak, and the presence of another zona pellucida-binding protein that probably works in concert with these ADAM complexes was suggested. Immunofluorescence testing suggested that ADAM20-like was localized on the anterior part of the sperm plasma membrane.