Studies on hydrolytic enzymes of chimpanzee semen

Pre-fertilization approach using α-l-fucosidase modulates zona pellucida hardening during bovine in vitro embryo production

The polyspermy occurrence is considerably lower under in vivo compared to in vitro embryo culture conditions, suggesting that the presence of some factors in the maternal environment is responsible for this. The α-L-fucosidase (FUCA) is a natural glycosidase present in the oviductal fluid, therefore, this study aimed at investigating the effect of adding FUCA to the hardening of the zona pellucida (ZP), polyspermy control, and embryonic yield and quality of bovine blastocysts produced in vitro. In the first experiment, the effect of FUCA (0.125 U/mL) was evaluated during the entire in vitro fertilization (IVF). However, it was demonstrated to be embryotoxic by completely inhibiting the blastocyst formation. In the second experiment, the FUCA (0.125 U/mL) was tested as short-term incubation before IVF (pre-fertilization step) for 30 min or 2 h, which demonstrated that FUCA treatment for 30 min resulted in ZP hardening. In the third experiment, a pre-fertilization FUCA treatment (1 h) at different concentrations (0, 0.0625, and 0.125 U/mL) showed that FUCA (0.0625 U/mL) improved pre-fertilization ZP hardening and tended to increase monospermic fertilization rates but did not improve embryo yield and quality. Together, it has been demonstrated that FUCA can induce oocyte pre-fertilization ZP hardening and might improve monospermic fertilization performance, and this effect is dependent on both variables (protein concentration and incubation time).

Sexual selection and sperm diversity in primates

Many aspects of primate sperm physiology and reproductive behavior have been influenced by sexual selection, especially in taxa exposed to sperm competition where females mate with multiple partners. Primate sperm diversity reflects therefore the evolutionary divergences of the different primate species and the impact of a combination of variables exerting selection pressures on sperm form, function, and competition. Thereby, mating systems, life cycle or ecological variables are some of the important factors driving sperm diversity and explaining variation in terms of sperm morphology, parameters or male sexual characters. Here, we address primate sperm diversity through a compilation of all data available in the literature concerning primate sperm parameters and relationships between them. We also review the factors that can influence primate sperm diversity (e.g. mating systems, trade-off between investments in precopulatory and postcopulatory sexual traits, male and female sexual behaviors, seasonality, social constraints, testosterone levels), and discuss also their relevance to our understanding of human reproduction.

Stabilization of membrane-associated alpha-L-fucosidase by the human sperm equatorial segment

Previous reports from this laboratory documented the existence of two novel isoforms of alpha-L-fucosidase in human semen and showed that membrane-associated alpha-L-fucosidase is cryptically held within the acrosomal compartment and enriched within the sperm equatorial segment. The occurrence of these novel isoforms is provocative. Sperm proteins potentially involved in sperm-egg interactions must maintain their functional integrity as they travel through the female reproductive tract. The goal of this project was to investigate the stability of membrane-associated alpha-L-fucosidase in human sperm. Whole seminal plasma and Percoll purified sperm cell populations were incubated for 72 h at 37 degrees C, with 5% CO(2) or ambient air. At various times during prolonged incubation, sperm cells were permeabilized with 0.1% Triton X-100 and enzyme assays using the fluorogenic substrate 4-MU-fuc were performed to evaluate the stability of both the seminal plasma and membrane-associated alpha-L-fucosidase. Here, we report seminal plasma alpha-L-fucosidase activity rapidly decreased within 24 h. Conversely, alpha-L-fucosidase activity from Percoll purified sperm cell populations persisted up to 72 h. Data from these experiments support the notions that (i) membrane-associated alpha-L-fucosidase is stable for extended periods of time, consistent with a possible role in sperm-egg interaction and (ii) membrane domains and compartmentalization within the human sperm are key to preserving protein integrity.

The effect of enzymes on semen viscosity in Llamas and Alpacas

The effect of four enzymes: collagenase, fibrinolysin, hyalurodinase, and trypsin were recorded on the viscosity, motility, percent live spermatozoa and acrosome integrity of Llama and Alpaca semen. Semen samples were collected using a modified artificial vagina for each of the five llamas and five alpacas. A 25% solution of the of enzyme at a concentration of 1mg/ml was added to the ejaculate. Analysis of variance was used to determine differences in eliminating viscosity and alterations in motility, percent live spermatozoa and the acrosomal integrity at 0 (time of semen collection), 2 and 5min. In Llama and Alpaca semen, collagenase eliminated viscosity in 100 and 99% of the samples, respectively. Correspondingly, fibrinolysin in 89 and 59%; hyalurodinase in 88 and 36%; and trypsin in 55 and 68% of the samples (p<0.05). In the Llama sperm, motility decreased (p<0.05) with the addition of fibrinolysin (28%), trypsin (13%), hyalurodinase (12%), and collagenase (4%). In Alpaca semen, the enzymes used had no effect on sperm motility. Percent live spermatozoa variably decreased after the addition of fibrinolysin, hyalurodinase and trypsin. There was no significant difference in the acrosome integrity in Llama and Alpaca makes following the addition of the enzymes. Overall, collagenase had little or no influence in decreasing motility, percent live spermatozoa and acrosome integrity, whereas, it was effective in eliminating semen viscosity.

Abnormalities in sperm acid glycosidases from infertile men with idiopathic oligoasthenoteratozoospermia

OBJECTIVE

To analyze and compare acid beta-glucuronidase, alpha-mannosidase, alpha-glycosidase, alpha-galactosidase, beta-galactosidase, and beta-N-acetylglucosaminidase activities in fertile and infertile patients.

DESIGN

An observational, controlled, clinical study.

SETTING

A university tertiary hospital.

PATIENT(S)

Thirty-six fertile controls, 24 infertile oligoasthenoteratozoospermic (OAT) patients, and 10 azoospermic patients, who served as negative controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Analysis of the six glycosidase activities in seminal plasma and in solubilized spermatozoa.

RESULT(S)

alpha-galactosidase and beta-galactosidase activities in spermatozoa were significantly correlated with the serum levels of gonadotropins both in fertile controls and in OAT patients. The relative contribution of alpha-galactosidase and beta-galactosidase from the soluble fraction of spermatozoa to the total activity measured in the ejaculate of OAT patients was significantly lower than in fertile controls. The activities of beta-galactosidase and beta-N-acetylglucosaminidase in the soluble fraction of spermatozoa from OAT patients were significantly lower than in fertile controls. In seminal plasma, the activity of alpha-mannosidase from OAT patients was significantly higher than in fertile controls. The activity of beta-N-acetylglucosaminidase in the nonsoluble fraction of spermatozoa from OAT patients was three times higher than in fertile controls.

CONCLUSION(S)

The abnormalities in the distributions and contents of alpha-galactosidase, beta-galactosidase, and beta-N-acetylglucosaminidase in sperm suggest possible functional defects in spermatozoa from OAT infertile patients.

Inhibition of rabbit sperm acrosomal enzymes by gossypol

The effect of gossypol on the activities of 10 acrosomal enzymes of the rabbit sperm was evaluated. Acrosin, Azocoll proteinase, neuraminidase, and arylsulfatase were significantly inhibited or completely inactivated by 12-76 microM gossypol. Hyaluronidase, beta-glucuronidase, and acid phosphatase were inhibited only at a higher concentration of gossypol (380 microM). Phospholipase C, alkaline phosphatase, and beta-N-Acetyl glucosaminidase were not inhibited even at 380 microM gossypol. Gossypol was found to be a noncompetitive inhibitor of arylsulfatase with a Ki of 120 microM. The inhibition was reversible and dose-dependent. As the acrosomal enzymes were more sensitive to the inhibition by gossypol compared to sperm enzymes involved in glycolysis or energy production, these assays may serve as a more reliable indicator for monitoring the occurrence of gossypol-induced sterility.

Purification and characterization of beta-glucuronidase from bull seminal plasma and its role in fertilization

Bull seminal plasma contains high levels of beta-glucuronidase. The present study describes the isolation and characterization of beta-glucuronidase, and its role in fertilization. beta-glucuronidase was purified by ion exchange chromatography, saccharolactone-agarose affinity chromatography, and gel filtration. The specific activity of the purified enzyme was 4,414 mumoles/mg protein/min. The purified enzyme showed a single band on 7.5% PAGE. On SDS-PAGE, the enzyme appeared to consist of four identical subunits of M(r) 75,000 each. The apparent Km and Vmax for beta-glucuronidase were 0.4 mM and 5.7 mumol/min using phenolpthalein mono-beta-glucuronic acid as the substrate. beta-glucuronidase appeared to accelerate the cumulus dispersion in vitro.

Correlations between the activities of semen acid phosphatase and Ca(2+)-dependent ATPase and age in different breeds of cocks

1. The present work aims to find a biochemical criterion for evaluating the evolution of sperm according to age through the study of the ATPase activity from the spermatozoa and the acid phosphatase from the seminal plasma of cocks from three different breeds. 2. The optimal parameters of action of the cock semen acid phosphatase and the Ca(2+)-dependent ATPase from the spermatozoa were studied. 3. The substrate specificity of the semen acid phosphatase and its inhibition by tartrate, fluoride, metavanadate, molybdate and Hg2+ were also studied. 4. The two enzymes were determined from the Sussex, Golden Cornish and Plymouth Rock breeds at different ages. 5. The data lead to the conclusion that some properties of bird spermatozoa are less influenced by breed while the acid phosphatase activity, secreted in the ductus deferens is a breed characteristic.

Quantitative changes of Ricinus communis agglutinin I and Helix pomatia lectin binding sites in the acrosome of rat spermatozoa during epididymal transit

During passage through the epididymis, spermatozoa undergo a number of changes which result in their acquisition of fertility and motility. Some of the changes that occur include loss of the cytoplasmic droplet and changes in sperm morphology, metabolism and properties of the nucleus and plasma membrane. Changes have also been reported in the acrosomic system of mammalian spermatozoa during their transit through the epididymis. In the present study, the quantitative changes of the glycoconjugate content in the acrosome of rat spermatozoa were examined during their passage through the epididymis using lectin-colloidal gold cytochemistry. Various regions of the epididymis (initial segment, caput, corpus and cauda epididymidis) were fixed by perfusion with 1% or 2% glutaraldehyde buffered in sodium cacodylate (0.1 M), dehydrated in ethanol and embedded without osmication in Lowicryl K4M. Lectin-colloidal gold labeling was performed on thin sections using Ricinus communis agglutinin I (RCA I) or Helix pomatia lectin (HPL) to detect D-galactose- and N-acetyl-D-galactosamine-containing glycoconjugates, respectively. The labeling density over the acrosome of the acrosomic system was evaluated as the number of gold particles per microns 2 of profile area using a Zeiss MOP-3 image analyzer. The overall mean labeling densities over the acrosome of spermatozoa for each lectin was estimated from 4 rats and over the four distinct epididymal regions. The mean labeling density of the acrosome with RCA I and HPL showed a similar pattern along the epididymis, although RCA I revealed approximately twice as many gold particles per epididymal region. In either case, there was a significant decrease in the labeling density of the acrosome of spermatozoa between the initial segment or caput epididymidis and cauda epididymidis (p less than 0.01). A similar decrease was also noted between the initial segment and corpus epididymidis (p less than 0.01). No change was found between the initial segment and caput epididymidis. Controls showed a virtual absence of labeling. These results suggest that in addition to a multitude of changes occurring to spermatozoa during epididymal transit, there are also significant quantitative changes in the glycoconjugate content within the acrosome.