Epididymal proteins Binder of SPerm Homologs 1 and 2 (BSPH1/2) are dispensable for male fertility and sperm motility in mice.

The binder of sperm family of proteins has been reported to be indispensable for sperm maturation and capacitation. However, their physiological functions in fertility have only been studied in vitro. CRISPR/Cas9 genome editing was utilized to generate double knockout (DKO) mice by simultaneously targeting the two murine binder of sperm genes, Bsph1 and Bsph2. To confirm that the homologous genes and proteins were completely eliminated in the DKO mice, different methods such as reverse transcription polymerase chain reaction, digital droplet-polymerase chain reaction and liquid chromatography tandem mass spectrometry were applied. Bsph1/2 DKO male mice were bred by intercrossing. Compared to wild type counterparts, male Bsph1/2 null mice, lacking BSPH1/2 proteins, were fertile with no differences in sperm motility and sperm count. However, the weights of male pups were significantly increased in Bsph1/2 double knockout mice in a time dependent manner spanning days 6 and 21, as well as 6 weeks of age. No change was detected in the weights of female pups during the same period. Taken together, these data indicate that BSPH1/2 proteins are dispensable for male fertility in mice but may influence growth.

Human Semenogelin 1 Promotes Sperm Survival in the Mouse Female Reproductive Tract.

Semenogelin 1 (SEMG1), a main component of human seminal plasma, is a multi-functional protein involved in the regulation of sperm motility and fertility. SEMG1 is orthologous to mouse seminal vesicle secretion 2 (SVS2), required for sperm survival in the female reproductive tract after copulation; however, its in vivo function remains unclear. In this study, we addressed this issue by examining the effect of recombinant SEMG1 on intrauterine mouse sperm survival. SEMG1 caused a dose-dependent decrease in mouse sperm motility, similar to its effect on human sperm, but SVS2 had no effect on mouse sperm motility. Mouse epididymal sperm in the presence of 100 µM SEMG1, a concentration that does not affect mouse sperm motility, were injected into the mouse uterus (intrauterine insemination, IUI). IUI combined with SEMG1 significantly increased the survival rate of intrauterine mouse sperm. The effect of SEMG1 on intrauterine sperm survival was comparable with that of SVS2. For clinical applications, three potentially sperm-protecting polypeptides that are easy to handle were designed from SEMG1, but their individual use was unable to mimic the ability of SEMG1. Our results indicate that SEMG1 has potential clinical applications for effective IUI and thereby for safe, simple, and effective internal fertilization.

Deletion of a Seminal Gene Cluster Reinforces a Crucial Role of SVS2 in Male Fertility.

Multiple genes, whose functions or expression are overlapping, compensate for the loss of one gene. A gene cluster in the mouse genome encodes five seminal vesicle proteins (SVS2, SVS3, SVS4, SVS5, and SVS6). These proteins are produced by male rodents and function in formation of the copulatory plug following mating. SVS2 plays an essential role in the successful internal fertilization by protecting the sperm membrane against a uterine immune attack. We hypothesized that the four remaining seminal vesicle proteins (SVPs) of this gene cluster may partially/completely compensate for the deficiency of SVS2. For confirming our hypothesis, we generated mice lacking the entire SVP-encoding gene cluster and compared their fecundity with Svs2-deficient (Svs2-/-) mice; that is, mice deficient in Svs2 alone. A single loxP site remained after the deletion of the Svs2 gene. Therefore, we inserted another loxP site by combining the CRISPR/Cas9 system with single-stranded oligodeoxynucleotides (ssODN). Male mice lacking the entire SVP-encoding gene cluster (Svs2-6-/- mice) and thereby all five SVP proteins, generated by the deletion of 100kbp genomic DNA, showed low fecundity. However, the fecundity level was comparable with that from Svs2-/- male mice. Our results demonstrate that SVS3, SVS4, SVS5, and SVS6 do not function in the protection of sperm against a uterine immune attack in the absence of SVS2. Thus, Svs2 is the critical gene in the SVP gene cluster.

Seminal vesicle secretory protein 7, PATE4, is not required for sperm function but for copulatory plug formation to ensure fecundity†.

Seminal vesicle secretions (SVSs), together with spermatozoa, are ejaculated into the female reproductive tract. SVS7, also known as PATE4, is one of the major SVS proteins found in the seminal vesicle, copulatory plug, and uterine fluid after copulation. Here, we generated Pate4 knockout (-/-) mice and examined the detailed function of PATE4 on male fecundity. The morphology and weight of Pate4-/- seminal vesicles were comparable to the control. Although Pate4-/- cauda epididymal spermatozoa have no overt defects during in vitro fertilization, Pate4-/- males were subfertile. We found that the copulatory plugs were smaller in the vagina of females mated with Pate4-/- males, leading to semen leakage and a decreased sperm count in the uterus. When the females mated with Pate4-/- males were immediately re-caged with Pate4+/+ males, the females had subsequent productive matings. When the cauda epididymal spermatozoa were injected into the uterus and plugged artificially [artificial insemination (AI)], Pate4-/- spermatozoa could efficiently fertilize eggs as compared to wild-type spermatozoa. We finally examined the effect of SVSs on AI, and observed no difference in fertilization rates between Pate4+/+ and Pate4-/- SVSs. In conclusion, PATE4 is a novel factor in forming the copulatory plug that inhibits sequential matings and maintains spermatozoa in the uterus to ensure male fecundity.

CRISPR-Cas9-mediated mutation revealed BSPH2 protein is dispensable for male fertility.

Members of the Binder of SPerm (BSP) superfamily have been identified in both human and mouse epididymis. These proteins are known to bind sperm membrane and promote sperm capacitation. Studies suggest that BSPH2 might play a different role in sperm functions from its counterparts; however, the role of BSPH2 remains mainly unexplored. To investigate whether the absence of one member of the BSP family could affect fertility, mice lacking Bsph2 expression were generated using clustered regularly interspaced short palindromic repeats (CRISPR) associated 9 (Cas9) technology. Knockout (KO) male mice were mated with wild-type (WT) females, and the number and weight of the pups were determined. Sperm motility in WT and KO was assessed using sperm class analyzer (SCA). Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used for protein identification. Fertility analysis of null Bsph2 mice did not reveal any phenotype. No differences were noticed on average litter size or average pup weight. Normal testis weight and morphology were observed in Bsph2+/- and Bsph2-/- compared to the WT. Quantitative polymerase chain reaction analyses revealed that Bsph1 messenger RNA expression was increased in mutant mice, whereas LC-MS/MS analysis displayed no increase in protein expression level. Taken together, we show the existence of redundant function for murine BSPH2 and the lack of BSPH2 itself does not lead to sterility.

Factors Influencing the Chaperone-Like Activity of Major Proteins of Mammalian Seminal Plasma, Equine HSP-1/2 and Bovine PDC-109: Effect of Membrane Binding, pH and Ionic Strength.

HSP-1/2 and PDC-109 belong to a family of fibronectin type II proteins, present in high concentrations in bovine and equine seminal plasma, respectively. These proteins act as extracellular small heat shock proteins and protect target/client proteins against various kinds of stress. They also exhibit characteristic binding to choline phospholipids present on the sperm plasma membrane and cause efflux of choline phospholipids and cholesterol, resulting in sperm capacitation. The current study demonstrates that hypersaline conditions decrease the chaperone-like activity (CLA) of HSP-1/2. On the other hand, lipoprotein aggregates formed by the binding of choline phospholipids to this protein exhibit higher CLA than HSP-1/2 alone in vitro; the increased CLA can be correlated to the increased surface hydrophobicity of the lipoprotein aggregates. Presence of cholesterol in the membrane was found to decrease such enhancement in the CLA. We have also observed that salinity of the medium affects the chaperone activity by altering the polydisperse nature of the HSP-1/2. Together these results indicate that hydrophobicity and polydispersity are important for the chaperone-like activity of HSP-1/2 and factors that can alter these properties of HSP-1/2 can modulate its CLA. Further, studies on PDC-109 show that the chaperone-like and membrane-destabilizing activities of this protein are differentially affected by change in pH.

New ultrastructural observations of human oocyte smooth endoplasmic reticulum tubular aggregates and cortical reaction: update on the molecular mechanisms involved / Nuevas observaciones ultraestructurales en ovocitos humanos de los agregados tubulares de retículo endoplásmico liso y de la reacción cortical: actualización sobre los mecanismos moleculares implicados

Introduction. The ultrastructure of the human mature metaphase-II oocyte before and after the cortical reaction has been previously described. However, we found a new vesicular aggregate associated with smooth endoplasmic reticulum tubular aggregates (aSERT) and new observations regarding the cortical reaction. Objectives. To describe at the ultrastructural level a novel vesicle aggregate associated with aSERT and new observations regarding the cortical reaction.Materials and methods. Donated, surplus mature oocytes were processed for transmission electron microscopy immediately after recover. Calcium detection was performed using the pyroantimonate technique. The cortical reaction was artificially induced by ionophore treatment. Results. We observed an accumulation of small vesicles at the periphery of aSERT. At high magnification these were composed by small pale vesicles coated by tiny vesicles, with associated dense materials, giving a rosette-like appearance. Adjacent to these there was another group of small dense vesicles incompletely coated by similar tiny vesicles. Using calcium detection at the ultrastructural level, antimonate deposits were observed in the tubules of aSERT and in the surrounding mitochondria but not in the rosette-like structures. Regarding cortical vesicles, although most previous studies described their contents as homogeneous dense, others referred the presence of another type of cortical vesicles whose contents were moderate dense. Using ionophore oocyte activation, we observed that moderate dense cortical vesicles may correspond to a progressive swelling of the dense cortical vesicles prior to exocytosis. Conclusions. We describe a novel vesicle aggregate associated to aSERT and new observations on the remodeling of cortical vesicles before exocytosis (AU)

Introducción. La ultraestructura del ovocito humano maduro en metafase-II humana antes y después de la reacción cortical se ha descrito previamente. Sin embargo, encontramos un nuevo agregado vesicular asociado a los agregados tubulares de retículo endoplásmico liso (aSERT) y nuevas observaciones con respecto a la reacción cortical. Objetivos. Describir a nivel ultraestructural un nuevo agregado vesicular asociado a los agregados tubulares de retículo endoplásmico liso y nuevas observaciones con respecto a la reacción cortical. Material y métodos. Se procesaron ovocitos maduros excedentes de ciclos de donante para microscopia electrónica de transmisión inmediatamente después de recuperarse. La detección de calcio se realizó mediante la técnica de piroantimoniato. La reacción cortical fue inducida artificialmente mediante tratamiento ionóforo. Resultados. Se observó una acumulación de vesículas pequeñas en la periferia de aSERT. A mayor aumento, estas estaban compuestas por pequeñas vesículas pálidas recubiertas por diminutas vesículas, con materiales densos asociados, dando una apariencia de roseta. Junto a ellas había otro grupo de pequeñas vesículas densas, incompletamente recubiertas por similares vesículas diminutas. Con el uso de la detección de calcio a nivel ultraestructural se observaron depósitos de antimoniato en los túbulos de aSERT y en las mitocondrias de los alrededores, pero no en las estructuras de roseta. En cuanto a las vesículas corticales, aunque la mayoría de los estudios anteriores describen su contenido como denso homogéneo, se refirió la presencia de otro tipo de vesículas corticales cuyo contenido era denso moderado. Con el uso de la activación de ovocitos con ionóforo, se observó que las vesículas corticales de densidad densa moderada pueden corresponder a una hinchazón progresiva de las vesículas corticales densas antes de la exocitosis. Conclusiones. Describimos una nuevo agregado vesicular asociado a aSERT y nuevas observaciones sobre la remodelación de vesículas corticales antes de la exocitosis (AU)

Abnormal Expression of Sg I is Closely Related to Seminal Vesiculitis.

OBJECTIVE: To investigate firstly the relationship between semenogelin I (Sg I) expression and seminal vesiculitis. Seminal vesiculitis is one of the most common diseases in male urogenital system. However, the cause and the pathogenesis of seminal vesiculitis remain unknown. Sg I, mainly synthesized and secreted by seminal vesicle, is abundant in human seminal plasma and has antibacterial activity. MATERIALS AND METHODS: Tissue samples were collected from 15 normal cases and 28 patients with seminal vesiculitis. Reverse transcription-polymerase chain reaction was performed to detect the expression difference of Sg I messenger ribonucleic acid (RNA) between normal seminal vesicle tissues and seminal vesiculitis tissues. Immunohistochemistry was applied to detect the expression difference of Sg I protein between the 2 groups. RESULTS: Reverse transcription-polymerase chain reaction showed the expression of Sg I messenger RNA in seminal vesiculitis tissues to be significantly lower than in normal seminal vesicle tissues. In most cases with seminal vesiculitis (78.6%), the same result was observed upon immunohistochemical analysis at the protein level. CONCLUSION: Abnormal expression of Sg I is closely related to seminal vesiculitis. Low expression of Sg I may play an important role in the occurrence and the development of seminal vesiculitis through weakening the antibacterial activity of seminal vesicle.

Seminal vesicle secretion 2 acts as a protectant of sperm sterols and prevents ectopic sperm capacitation in mice.

Seminal vesicle secretion 2 (SVS2) is a protein secreted by the mouse seminal vesicle. We previously demonstrated that SVS2 regulates fertilization in mice; SVS2 is attached to a ganglioside GM1 on the plasma membrane of the sperm head and inhibits sperm capacitation in in vitro fertilization as a decapacitation factor. Furthermore, male mice lacking SVS2 display prominently reduced fertility in vivo, which indicates that SVS2 protects spermatozoa from some spermicidal attack in the uterus. In this study, we tried to investigate the mechanisms by which SVS2 controls in vivo sperm capacitation. SVS2-deficient males that mated with wild-type partners resulted in decreased cholesterol levels on ejaculated sperm in the uterine cavity. SVS2 prevented cholesterol efflux from the sperm plasma membrane and incorporated liberated cholesterol in the sperm plasma membrane, thereby reversibly preventing the induction of sperm capacitation by bovine serum albumin and methyl-beta-cyclodextrin in vitro. SVS2 enters the uterus and the uterotubal junction, arresting sperm capacitation in this area. Therefore, our results show that SVS2 keeps sterols on the sperm plasma membrane and plays a key role in unlocking sperm capacitation in vivo.

Murine Binder of SPerm homolog 2 (BSPH2): the black sheep of the BSP superfamily.

Proteins of the Binder of SPerm superfamily are known to bind choline phospholipids on sperm membrane and promote sperm capacitation. The current study focuses on the biochemical and functional characterization of the murine Binder of SPerm homolog 2 (BSPH2). A recombinant protein (rec-BSPH2) was expressed in Escherichia coli Rosetta-gami B (DE3)pLysS cells using pET32a vector. It was purified by immobilized metal ion affinity chromatography and refolded on column using a decreasing urea gradient. Rec-BSPH2 was found to share some binding characteristics with other BSP proteins, such as binding to gelatin, heparin, and epididymal sperm. Rec-BSPH2 as well as murine recombinant BSPH1 were found to have different immunofluorescence patterns when bound to uncapacitated versus capacitated sperm, indicating a rearrangement of these proteins on sperm surface during or following capacitation. Surprisingly, rec-BSPH2 was unable to bind phosphorylcholine liposomes or promote sperm capacitation. It is the first time that such results are reported for proteins of the BSP family. The results indicate that murine BSPH1 and BSPH2 might not have redundant functions, as is the case with bovine BSPs. This study could lead to a better understanding of the role of BSP proteins in sperm functions and the existence of redundant BSP proteins in the reproductive tract.

Bovine seminal PDC-109 protein: an overview of biochemical and functional properties.

Although long-term storage of bovine semen is desirable for wider use, successful cryopreservation depends on several factors, including various proteins present in seminal plasma. One such group of proteins, viz. bovine seminal plasma (BSP) proteins represents the major protein fraction in bovine seminal plasma. They constitute three major heparin-binding (HB-) acidic proteins secreted by seminal vesicles, viz. BSP-A1/-A2 (PDC-109), BSP-A3 and BSP-30-kDa. By purification studies it was deduced that PDC-109 is a polypeptide of 109 amino acids and contains two tandem repeating fibronectin type-II (Fn-II) domains, preceded by a 23 residue N-terminal domain. Though BSP-A1 and BSP-A2 are biochemically similar they differ only in glycosylation and their mixture is called PDC-109 or gonadostatins. PDC-109 exists as a polydisperse, multimeric self-associated molecule and possesses multifunctional properties, viz. binding to the surface of plasma membrane of spermatozoa causing conformational change in the sperm surface proteins and enhances motility. Besides binding, PDC-109 protein provokes cholesterol efflux from sperm membrane and promotes sperm reservoir by interacting with oviductal membrane. Interaction of sperm with PDC-109 protein induces sperm capacitation and acrosome reaction. However, prolonged exposure of spermatozoa with free floating PDC-109 protein as during processing for preservation, increases cholesterol efflux from spermatozoa. The efflux of sperm membrane cholesterol and disturbance in cholesterol:phospholipids ratio causes destabilization of plasma membrane thereby inducing cryoinjury to the sperm. In this review, the biochemical, functional properties of PDC-109 protein and its role during semen cryopreservation is summarized.

[Activities of the fragments of semenogelin I: an update].

Semenogelin I (Sg I) and the fragments of peptides hydrolyzed from Sg I by prostate-specific antigen have multiple biological activities. There exists a controversy over the inhibitory effect of the key fragment on sperm motility. This article focuses on the sperm-inhibiting and antibacterial activities of the fragments of Sg I-derived peptides and illustrates the supposition concerning the most controversial aspect. A deeper insight into the action mechanisms of Sg I-derived peptides may help improve the methods of sperm screening and provide a new perspective in the management of asthenozoospermia and urinary tract infection.

Characterization of recombinant murine binder of sperm protein homolog 1 and its role in capacitation.

Sperm capacitation is a maturation step that is deemed to be essential for sperm to fertilize an oocyte. A family of proteins, the binder of sperm (BSP), are known to bind choline phospholipids on sperm membranes and promote capacitation in bulls and boars. Recently, BSP-homologous genes have been identified in the epididymal tissues of human (BSPH1) and mouse (Bsph1, Bsph2). The aim of this study was to determine the binding characteristics of the murine binder of sperm protein homolog 1 (BSPH1) and evaluate its effects on sperm capacitation. Since it is not possible to purify the native BSP proteins from human and mouse in sufficient quantity, a murine recombinant BSPH1 (rec-BSPH1) was produced and used for the functional studies. Similarly to BSP proteins from other species, rec-BSPH1 bound to gelatin, heparin, phosphatidylcholine liposomes, and sperm. Both native BSPH1 and rec-BSPH1 were detected on the head and the midpiece region of sperm, although a stronger signal was detected on the midpiece region when sperm were incubated in a capacitating media containing bovine serum albumin. More importantly, murine rec-BSPH1 was able to capacitate sperm, but was unable to induce the acrosome reaction. These results show that murine epididymal BSPH1 shares many biochemical and functional characteristics with BSP proteins secreted by seminal vesicles of ungulates, and suggest that it might play a similar role in sperm functions.

Capacitation suppression by mouse seminal vesicle autoantigen involves a decrease in plasma membrane Ca2+-ATPase (PMCA)-mediated intracellular calcium.

Successful fertilization is tightly regulated by capacitation and decapacitation processes. Without appropriate decapacitation regulation, sperm would undergo a spontaneous acrosome reaction which leads to loss of fertilization ability. Seminal plasma is known to negatively regulate sperm capacitation. However, the suppressive mechanisms still remain unclear. In this study, we demonstrate the decapacitation mechanism of mouse seminal vesicle autoantigen (SVA) might target membrane sphingomyelin (SPM) and regulate plasma membrane Ca(2+)-ATPase (PMCA) activity. The SVA was shown to suppress sperm capacitation induced by a broad panel of capacitation factors (bovine serum albumin (BSA), PAF, and cyclodextrin (CD)). Furthermore, SVA significantly decreased [Ca(2+)](i) and NaHCO(3)-induced [cAMP](i). Cyclic AMP agonists bypassed the SVA's suppressive ability. Importantly, the SVA may regulate PMCA activity which was evidenced by the fact that the SVA decreased the [Ca(2+)](i) and intracellular pH (pH(i)) of sperm; meanwhile, a PMCA inhibitor (carboxyeosin) could reverse SVA's suppression of [Ca(2+)](i). The potential target of the SVA on membrane SPM/lipid rafts was highlighted by the high binding affinity of SPM-SVA (with a K(d) of ~3 µM) which was close to the IC(50) of SVA's suppressive activity. Additionally, treatment of mink lung epithelial cells with the SVA enhanced plasminogen activator inhibitor (PAI)-1 expression stimulated by tumor growth factor (TGF)-ß and CD. These observations supported the membrane lipid-raft targeting of SVA. In summary, in this paper, we demonstrate that the decapacitation mechanism of the SVA might target membrane sphingolipid SPM and regulate PMCA activity to lower [Ca(2+)](i), thereby decreasing the [cAMP](i) level and preventing sperm pre-capacitation.

Levels of semenogelin in human spermatozoa decrease during capacitation: involvement of reactive oxygen species and zinc.

BACKGROUND: Semenogelin (Sg), the main protein of human semen coagulum, prevents sperm capacitation. The objective of this study was to examine the role of Sg and its mechanism of action. METHODS AND RESULTS: Sg blocked sperm capacitation triggered by various stimuli, via inhibition of superoxide anion (O(2)*-; luminescence assay) and nitric oxide (NO*; tested using diaminofluorescein) generation. Triton-soluble and -insoluble sperm fractions contained Sg and Sg peptides (immunoblotting), the level of which decreased with initiation of capacitation. This drop was prevented by superoxide dismutase and NO* synthase inhibitor and was reproduced by addition of O(2)*- and NO*. Zinc (Zn(2+)) blocked and a zinc chelator (TPEN) promoted the decline in Sg levels. There was a decreased labelling of Sg on the head in capacitating spermatozoa with the two fixation techniques tested (immunocytochemistry). Reactive oxygen species (ROS) (O(2)*- and NO*) caused, these changes, and zinc prevented them. Spermatozoa quickly internalized Sg upon incubation and Sg was then rapidly degraded in a zinc-inhibitable manner. CONCLUSIONS: Sg blocked capacitation mainly via inhibition of ROS generation. Spermatozoa appeared permeable to Sg and processed Sg in a zinc-inhibitable fashion. ROS themselves could promote sperm disposal of Sg which maybe one of the mechanisms that allows initiation of capacitation.

Arrangement of PMCA4 in bovine sperm membrane fractions.

The plasma membrane Ca(2+) -ATPase (PMCA) is the main restorer of Ca(2+) balance in sperm. Particularly, PMCA isoform 4 has an essential function in sperm fertility by its participation in gaining sperm hypermotility. PMCA activity is influenced by its lipid environment. Sperm membranes exhibit lipid raft microdomains or detergent-resistant membrane domains, enriched in sphingolipids and cholesterol, forming functional specialized areas. Lipid and protein composition of lipid rafts alters during the capacitation process, which is characterized by a cholesterol efflux. In this study, the localization of PMCA4 in lipid membrane fractions of the sperm plasma membrane was investigated. We identified PMCA4 in both the detergent-resistant membrane (DRM) and in the detergent-soluble (DS) fraction of caput and cauda sperm, respectively. Capacitation did not influence PMCA4 localization. In immunocytochemical studies PMCA4 was co-localized with the lipid raft/DRM marker caveolin in the mid piece of caput and cauda sperm. Functional studies with seminal vesicle major protein PDC-109 showed that the Ca(2+) -ATPase activity in DS fractions of cauda sperm and capacitated cauda sperm was stronger enhanced than in the DRMs. In both fractions the effect was statistically significant. In contrast, in lipid overlay experiments PDC-109 interacted stronger with the lipids extracted from DRMs than with lipids extracted from DS. Our results indicate a possible functional compartmentalization of PMCA in bull sperm membranes and point to a presumptive, yet unknown interaction partner of Ca(2+) -ATPase and PDC-109, mediating the PDC-109 action from DRMs to the DS fraction of sperm plasma membrane.

[Semenogelin and sperm motility inhibition: an update].

Semen liquefaction and sperm capacitation are the key processes for sperm to acquire forward movement ability. In these processes, semenogelin plays a vital role by directly participating in the formation of semen coagulation, collaborating with other protease and metal ions from the male reproductive tract, and then reacting with the surface of sperm cells, finally involved in the regulation of these processes and ensuring sperm's acquisition of forward movement ability.

The physiological roles of the boar ejaculate.

During ejaculation in the boar, sperm cohorts emitted in epididymal cauda fluid are sequentially exposed and resuspended in different mixtures of accessory sex gland secretion. This paper reviews the relevance of such unevenly composed fractions of seminal plasma (SP) in vivo on sperm transport and sperm function and how this knowledge could benefit boar semen processing for artificial insemination (AI). The firstly ejaculated spermatozoa (first 10 ml of the sperm-rich fraction, SRF [P1]) remain mainly exposed to epididymal cauda fluid and its specific proteins i.e. various lipocalins, including the fertility-related prostaglandin D synthase; than to prostatic and initial vesicular gland secretions. P1-spermatozoa are hence exposed to less bicarbonate, zinc or fructose and mainly to PSP-I spermadhesin; than if they were in the rest of the SRF and the post-SRF (P2). Since the P1-SP is less destabilizing for sperm membrane and chromatin, P1-spermatozoa sustain most in vitro procedures, including cryopreservation, the best. Moreover, ejaculated firstly, the P1-spermatozoa seem also those deposited by the boar as a vanguard cohort, thus becoming overrepresented in the oviductal sperm reservoir (SR). This vanguard SR-entry occurs before the endometrial signalling of SP components (as PSP-I/PSP-II and cytokines) causes a massive influx of the innate defensive PMNs to cleanse the uterus from eventual pathogens, superfluous spermatozoa and the allogeneic SP. The SP also conditions the mucosal immunity of the female genital tract, to tolerate the SR-spermatozoa and the semi-allogeneic conceptus. These in vivo gathered data can be extrapolated into procedures for handling boar spermatozoa in vitro for AI and other biotechnologies, including simplified cryopreservation.

[Advances in the study of Semenogelin I from human seminal vesicles].

Sperm acquires capacity of motility and fertility during the process of semen coagulation and liquefaction. The main coagulative protein is Semenogelin I (Sg I), specifically produced by seminal vesicles, and then decomposed by prostate specific antigens (PSA) in sperm liquefaction into a series of small fragments. These fragments, with a variety of physiological functions, are very important for the regulation of sperm capacity acquisition and progressive movement.