Functional significance of responsiveness to capacitating conditions in boar spermatozoa.
TL;DR: The combination of sperm responsiveness parameters applied here is a suitable tool for the evaluation of sperm function and improved the prediction level of multiple regression models for farrowing rate and litter size.
About: This article is published in Theriogenology.The article was published on 2005-11-01. It has received 45 citations till now. The article focuses on the topics: Sperm & Capacitation.
Citations
More filters
TL;DR: The discussion of the major aspects of ZAG from its gene structure to function and metabolism is discussed, which suggests that ZAG may have a role in the expression of the immune response.
Abstract: Zinc alpha 2-glycoprotein (ZAG) is a protein of interest because of its ability to play many important functions in the human body, including fertilization and lipid mobilization After the discovery of this molecule, during the last 5 decades, various studies have been documented on its structure and functions, but still, it is considered as a protein with an unknown function Its expression is regulated by glucocorticoids Due to its high sequence homology with lipid-mobilizing factor and high expression in cancer cachexia, it is considered as a novel adipokine On the other hand, structural organization and fold is similar to MHC class I antigen-presenting molecule; hence, ZAG may have a role in the expression of the immune response The function of ZAG under physiologic and cancerous conditions remains mysterious but is considered as a tumor biomarker for various carcinomas There are several unrelated functions that are attributed to ZAG, such as RNase activity, regulation of melanin production, hindering tumor proliferation, and transport of nephritic by-products This article deals with the discussion of the major aspects of ZAG from its gene structure to function and metabolism
207 citations
Cites background from "Functional significance of responsi..."
...The sperm motility is a key factor to determine semen quality and its fertilizing capacity (104-106), which is widely controlled by a variety of...
[...]
TL;DR: Current and past data, correlating laboratory assay data with sperm fertility are presented in an effort to determine which types of assays are important to conduct and when to conduct them.
167 citations
TL;DR: This work has developed a simple and cost-efficient flow cytometric approach for identifying non-sperm particles that can be carried out in parallel with functional assessments and is suitable for obtaining accurate sperm counts during routine semen evaluation.
111 citations
Cites methods from "Functional significance of responsi..."
...The percentages of sperm with intact plasma and acrosome membrane were also assessed (in parallel) by PI and FITC-PNA as described previously [8]....
[...]
...The methodology and system settings were as previously described [8,9], with EM520 bandpass optics (detection width 515–560 nm) to detect green fluorescence (CFDA, SYBR14, FITC-PNA) in FL-1, and with RG630 optics (630 nm longpass) to detect PI fluorescence in FL-3....
[...]
TL;DR: Assessing both the conventional sperm quality parameters and the immunolabeling of three proteins involved in the physiology of the sperm cell suggest that analyzing these sperm kinematic parameters could be a useful tool for predicting the potential freezability of an ejaculate.
97 citations
Cites background from "Functional significance of responsi..."
...Indeed, the hyperactivation is also higher in subfertile boars during real capacitation [60], which indicates the magnitude of the hyperactivated movement could also be dependent on the presence of damaged sperm; for example, in bull it is reported that demembranated spermatozoa are highly sensitive to Ca concentrations that promote hyperactivation [61]....
[...]
TL;DR: Improved techniques for evaluating semen characteristics directly related to the fertilization process, such as IVM-IVF assays, analysis of seminal plasma protein markers, and discriminatory tests of sperm motility and morphology are reviewed with the goal of identifying high-index boars whose fertility is sustained when low numbers of sperm are used for AI.
90 citations
References
More filters
TL;DR: It is suggested that the sperm penetration bioassay can be reliably used to test the fertilizing potential of bull sperm in vitro and is strongly correlated with the conception rate.
61 citations
"Functional significance of responsi..." refers background in this paper
...Themembrane changes in response to calcium ionophore have been evaluated in a series of fluorescence microscopic and flow cytometric studies with bull sperm [16–18]....
[...]
TL;DR: In the guinea-pig, a sperm plasma membrane protein is a strong candidate for the mediator of the fusion process by which the egg engulfs the sperm, and in the mouse, a 94-kDa protein appears essential for this binding.
Abstract: Sexual reproduction requires that the gamete carrying the male-derived haploid chromatin join with the gamete carrying the female-derived haploid chromatin during fertilization to produce the diploid zygote. To accomplish this feat, the sperm must not only meet the egg, it must recognize the egg and be recognized in turn by the egg, and in the end must enter and be engulfed by the egg. In this selective overview of gamete interactions that lead to fertilization, encounters of three kinds, followed by the finale of gamete fusion, are considered from the sperm's viewpoint, with particular emphasis on the mammalian species with the mouse as the principal model. The first encounter is with the zona pellucida of the egg, to whose surface the sperm must bind. Mouse sperm appear to have four binding sites for zona ligands. Three interact with sugar moieties of the oligosaccharide chains of the mouse zona glycoprotein ZP3; the fourth binds a peptide backbone arginine. Capacitation is not required for this encounter, but is obligate for the second encounter--induction of the acrosome reaction in the bound sperm. The acrosome reaction is an exocytotic process that makes available the enzymatic machinery needed for sperm penetration the zona which is the end point of a sequence of reactions directed by intracellular signalling systems. In mouse sperm, these systems are presumed to be activated by ligands on ZP3 binding to ligand-specific sperm receptors with consequent aggregation of receptors. No receptor has been identified with certainty, nor have candidates for putative ZP3 ligands been identified. Completion of the acrosome reaction allows the sperm to penetrate the zona and, bind to the egg plasma membrane, thereby completing the third encounter. In the mouse, a 94-kDa protein appears essential for this binding. In the guinea-pig, a sperm plasma membrane protein (formerly PH-30, now fertilin), is a strong candidate for the mediator of the fusion process by which the egg engulfs the sperm. Decondensation of the sperm chromatin reverses the remarkable packing of DNA organized by sperm protamines. Mitochondrial DNA is also engulfed by the egg; the question of whether this DNA makes a small finite, or null, contribution to cytosolic inheritance is still in debate. The puzzles attending these encounters are presented as reminders of the intricacy and fascination, as well as of the vital necessity, of gamete interaction.
53 citations
TL;DR: Four topical aspects of Fallopian tube physiology that bear on either successful fertilization or early development of the zygote are reviewed, with strong arguments pointing to completion of these processes in the specific fluids at the ampullary-isthmic junction.
Abstract: Contents This essay reviews four topical aspects of Fallopian tube physiology that bear on either successful fertilization or early development of the zygote. An initial focus is on glycoprotein secretions of the duct that accumulate as a viscous mucus in the caudal isthmus. Because this is the site of the pre-ovulatory sperm reservoir, an involvement of the secretions is considered in: preventing uterine and ampullary tubal fluids from entering the functional sperm reservoir; removing residual male secretions from the sperm surface; deflecting spermatozoa towards endosalpingeal organelles and reducing flagellar beat before ovulation. The subtle prompting of flagellar movement with impending ovulation is examined in terms of potential reactivation mechanisms, with overall control attributed to increasing secretion of progesterone. The site of full capacitation and the acrosome reaction in a fertilizing spermatozoon is then debated, with strong arguments pointing to completion of these processes in the specific fluids at the ampullary-isthmic junction. Finally, the synthetic activity of cumulus cells released at ovulation as a paracrine tissue in the Fallopian tube is highlighted with reference to steroid hormones, peptides and cytokines. Not only does the suspension of granulosa-derived cells influence the process of fertilization, but also it may amplify oocyte or embryonic signals to the endosalpinx and ipsilateral ovary.
51 citations
"Functional significance of responsi..." refers background in this paper
...The completion of capacitation apparently takes place after release of sperm from the oviduct [36,37]....
[...]
...If capacitation is completed by the synergistic action of fluid constituents at the ampullary-isthmic junction soon after ovulation [36,38], then the life span of the oocyte (less than 8 h) would represent the upper limit for the time window of capacitation in vivo....
[...]
TL;DR: The addition of 0.5% (v/v) of Equex STM Paste to a Tris-egg yolk based extender significantly improved the post-thaw longevity of dog spermatozoa, but the same concentration of EquEx Pasta had no significant beneficial effects.
Abstract: The addition of 0.5% (v/v) of Equex STM Paste (Nova Chemical Sales, Scituate Inc., MA, USA), whose active ingredient is sodium dodecyl sulphate (SDS), to a Tris-egg yolk extender was demonstrated to improve the longevity of frozen-thawed dog spermatozoa during in vitro incubation at 38 degrees C. The aim of the first experiment was to compare the effects of two SDS-containing compounds, Equex STM Paste and Equex Pasta (Minitub, Tiefenbach, Germany), when added to a Tris-egg yolk based extender, on the post-thaw longevity of dog spermatozoa, as well as on the intracellular Ca2+ concentration of spermatozoa, during post-thaw incubation at 38 degrees C. The post-thaw sperm survival and longevity, as well as the quality of the sperm movement, were significantly better when using Equex STM Paste. Such prolonged sperm longevity, however, was associated to a higher intracellular Ca2+ concentration in a large subpopulation of the live spermatozoa. A second experiment was aimed to evaluate the effects of sperm dilution immediately post-thaw with a Tris buffer containing glucose or fructose. The two Tris buffers were no different for any of the sperm parameters studied. The aim of a third experiment was to evaluate the sperm longevity, motility patterns and intracellular Ca2+ concentration of cryopreserved dog spermatozoa during post-thaw incubation in capacitating conditions [canine capacitating medium (CCM) with or without 5 microg/ml of heparin]. Heparin had no significant effects on any of the sperm parameters evaluated. During the first 8 h of incubation, the majority of the live spermatozoa had a high intracellular Ca2+ content. However, after 8-10 h of incubation, it had significantly declined. The highest proportion of fast motile sperm, and the highest curvilinear velocity, average path velocity and amplitude of lateral head displacement for the total motile sperm were observed during the 2-4-h incubation period. It was concluded that: (a) the addition of 0.5% (v/v) of Equex STM Paste to a Tris-egg yolk based extender significantly improved the post-thaw longevity of dog spermatozoa, but the same concentration of Equex Pasta had no significant beneficial effects; (b) sperm dilution after thawing with a Tris buffer containing glucose or fructose made no difference in post-thaw sperm longevity; (c) the addition of 5 microg/ml of heparin to CCM had no significant capacitating effects on frozen-thawed dog spermatozoa.
47 citations
TL;DR: The extent to which biochemical or molecular studies portray changes in the vanguard of fertilizing spermatozoa needs to be questioned, more likely to be descriptive of overall changes in very large numbers of sperm cells at diverse stages of maturation.
Abstract: Contents
In terms of experimental studies of the process of fertilization in mammals, this essay attempts to give a balanced assessment of current interpretations and to raise questions of direct relevance to two fields of research. First, the nature of pre-ovulatory sperm–endosalpingeal binding is set in a physiological perspective, and examination of this dynamic process in vitro is shown to suffer from serious shortcomings. In particular, sperm–epithelial binding reactions demonstrated in cultures of endosalpingeal cells may represent only a portion of the binding reaction in vivo or, as revealed by sperm binding to the tracheal epithelium, could be largely non-specific. Second, concerning the subsequent phase of binding of a fertilizing spermatozoon to the zona pellucida, the nature of the initial contact arrest of the sperm head is evaluated, especially in the light of the highly uneven or ‘pitted’ surface of this outer coating of the oocyte. Bearing in mind the active phase of oviduct macromolecular secretion that continues after ovulation, the question is posed as to how functional sperm binding sites are preserved on the surface of the zona pellucida rather than masked by epithelial and cumulus cell secretions. Finally, it is recalled that initial sperm : egg ratios at the site of fertilization in the ampullary–isthmic region of the oviduct are close to unity in diverse species of mammal, such fertilizing spermatozoa being released from prominent reserves in the caudal isthmus shortly before the time of ovulation. On strictly quantitative grounds, therefore, the extent to which biochemical or molecular studies portray changes in the vanguard of fertilizing spermatozoa needs to be questioned. Such studies are more likely to be descriptive of overall changes in very large numbers of sperm cells at diverse stages of maturation.
46 citations
"Functional significance of responsi..." refers background in this paper
...The completion of capacitation apparently takes place after release of sperm from the oviduct [36,37]....
[...]