Proteomic analysis of the reproductive tract fluids from tropically-adapted Santa Ines rams

Molecular Biomarkers of Canine Reproductive Functions

The aim of the current study is to review potential molecular biomarker substances selected so far as useful for assessing the quality of dog semen. Proteins, lipids, carbohydrates, and ions can serve as molecular biomarkers of reproductive functions (BRFs) for evaluating male reproductive health and identifying potential risk factors for infertility or reproductive disorders. Evaluation of BRF levels in semen samples or reproductive tissues may provide insights into the underlying causes of infertility, such as impaired sperm function, abnormal sperm-egg interaction, or dysfunction of the male reproductive tract. Molecular biomarker proteins may be divided into two groups: proteins that are well-studied, such as A-kinase anchoring proteins (AKAPs), albumins (ALBs), alkaline phosphatase (ALPL), clusterin (CLU), canine prostate-specific esterase (CPSE), cysteine-rich secretory protein 2 (CRISP2), lactotransferrin (LTF), metalloproteinases (MMPs), and osteopontin (OPN) and proteins that are not well-studied. Non-protein markers include lipid-based substances (fatty acids, phosphatidylcholine), carbohydrates (glycosaminoglycans), and ions (zinc, calcium). Assessing the levels of BRFs in semen samples may provide valuable information for breeding management and reproductive assessments in dogs. This review systematizes current knowledge that could serve as a starting point for developing practical tests with the use of biomarkers of canine reproductive functions and their predictive value for assisted reproductive technique outcomes and semen preservation.

Proteomic Insights into Seminal Plasma and Spermatozoa Proteins of Small-Spotted Catsharks, Scyliorhinus canicula: Implications for Reproductive Conservation in Aquariums

In the ex situ conservation of chondrichthyan species, successful reproduction in aquaria is essential. However, these species often exhibit reduced reproductive success under human care. A key aspect is that conventional sperm analyses do not provide insights into the functional competence of sperm. However, proteomics analysis enables a better understanding of male physiology, gaining relevance as a powerful tool for discovering protein biomarkers related to fertility. The present work aims to build the first proteome database for shark semen and to investigate the proteomic profiles of seminal plasma and spermatozoa from small-spotted catsharks (Scyliorhinus canicula) related to the underlying adaptations to both natural and aquarium environments, thereby identifying the reproductive impact in aquarium specimens. A total of 305 seminal plasma and 535 spermatozoa proteins were identified. Among these, 89 proteins (29.2% of the seminal plasma set) were common to both spermatozoa and seminal plasma. In the seminal plasma, only adenosylhomocysteinase protein showed differential abundance (DAP) between wild and aquarium animals. With respect to the spermatozoa proteins, a total of 107 DAPs were found between groups. Gene Ontology enrichment analysis highlighted the primary functional roles of these DAPs involved in oxidoreductase activity. Additionally, KEGG analysis indicated that these DAPs were primarily associated with metabolic pathways and carbon metabolism. In conclusion, we have successfully generated an initial proteome database for S. canicula seminal plasma and spermatozoa. Furthermore, we have identified protein variations, predominantly within spermatozoa, between aquarium and wild populations of S. canicula. These findings provide a foundation for future biomarker discovery in shark reproduction studies. However, additional research is required to determine whether these protein variations correlate with reproductive declines in captive sharks.

An updated review on the application of proteomics to explore sperm cryoinjury mechanisms in livestock animals

This comprehensive review critically examines the application of proteomics in understanding sperm cryoinjury mechanisms in livestock animals, in the context of the widespread use of semen cryopreservation for genetic conservation. Despite its global adoption, cryopreservation often detrimentally affects sperm quality and fertility due to cryoinjuries. These injuries primarily arise from ice crystal formation, osmotic shifts, oxidative stress, and the reorganization of membrane proteins and lipids during freezing and thawing, leading to premature capacitation-like changes. Moreover, the cryopreservation process induces proteome remodeling in mammalian sperm. Although there have been technological advances in semen cryopreservation, the precise mechanisms of mammalian sperm cryoinjury remain elusive. This review offers an in-depth exploration of how recent advancements in proteomic technologies have enabled a detailed investigation into these molecular disruptions. It presents an analysis of protein-level alterations post-thaw and their impact on sperm viability and functionality. Additionally, it discusses the role of proteomics in refining cryopreservation techniques to mitigate cryoinjury and enhance reproductive outcomes in livestock. This work synthesizes current knowledge, highlights gaps, and suggests directions for future research in animal reproductive science and biotechnology.

Sperm traits and seminal plasma proteome of locally adapted hairy rams subjected to intermittent scrotal insulation

The present study evaluated the effects of heat stress on reproductive parameters of hairy rams. Six animals were subjected to scrotal insulation during four consecutive nights (6 PM - 6 AM). Day (D) 0 was the first day of insulation. Scrotal circumference increased from 30.5 ± 0.3 cm (at pre-insulation) to 31.8 ± 0.4 cm on D4, decreased 3.9 cm on D28, returning to 30.6 ± 0.6 cm on D57. Sperm concentration decreased from 3.7 ± 0.12 ×109 sperm/mL before insulation to 2.6 ± 0.1 ×109 on D23, returning to normal on D57. Sperm motility averaged 75 ± 2.9% before insulation, was undetectable on D23, and became normal on D77. Sperm with normal morphology reached 5.9 ± 2.6% on D35 but recovered (86.8 ± 2.1%) on D91. Sperm DNA integrity decreased from 86.5 ± 4.7% before insulation to 11.1 ± 3.7% on D63, returning to pre-insulation values on D120. Sperm BSP immunostaining was reduced after scrotal insulation. Variations in seminal protein abundances coincided with changes in sperm parameters. Seminal plasma superoxide dismutase, carboxypeptidase Q-precursor and NPC intracellular cholesterol transporter 2 decreased on D18, returning to normal after D28. Albumin, inhibitor of carbonic anhydrase precursor, EGF-like repeat and discoid I-like domain-containing protein 3 and polymeric immunoglobulin receptor increased after insulation. In summary, intermittent scrotal insulation drastically altered ram sperm attributes and seminal proteins, especially those associated with oxidative stress. Knowledge of animal´s response to thermal stress is vital in the scenario of climate changes.

Identification and functional analysis of differentially expressed proteins in high and low freezing tolerance sheep sperm

The purpose of this study was to identify proteins associated with differences in the freezing tolerance of sheep sperm and to analyze their functions. Qualified fresh semen from four breeds of rams, the Australian White, white-head Dorper, Black-head Dorper, and Hu sheep breeds, were selected for cryopreservation. The sperm freezing tolerance was investigated by evaluation of the overall vitality, progressive vitality, and rapidly advance vitality of the sperm. A differential model of sperm freezing tolerance was constructed for sheep breeds showing significant differences. Differentially expressed proteins associated with sperm freezing tolerance were identified using iTRAQ and the protein functions were analyzed. It was found that sperm freezing tolerance was best in Hu sheep and worst in white-head Dorper sheep. These two breeds were used for the construction of a model based on differences in freezing tolerance and the identification of sperm proteins expressed differentially before freezing and after thawing. A total of 128 differentially expressed proteins (88 up-regulated and 40 down-regulated) were identified before freezing and after thawing in Hu sheep sperm (fresh/frozen Hu sheep sperm referred to as HL vs. HF), while 219 differentially expressed proteins (106 up-regulated and 113 down-regulated) were identified in white-head Dorper sheep (fresh/frozen white-head Dorper sheep sperm referred to as WL vs. WF). A comparison of these differentially expressed proteins showed that 57 proteins overlapped between the two breeds while 71 were only expressed in Hu sheep and 162 were only expressed in white-head Dorper sheep. Functional annotation and enrichment analyses of differentially expressed proteins down-regulated in Hu sheep involved in phosphorylation of phosphatidylinositol phosphate kinases, regulation of GTPase activity and glycolysis/gluconeogenesis signaling pathway. Up-regulated proteins of Hu sheep participated in oxidoreductase activity and oxidative phosphorylation process of sperm freezing. Furthermore, down-regulated in white-head Dorper sheep involved in the metabolic regulation of carbohydrate and nuclear sugar metabolism. Up-regulated proteins of white-head Dorper sheep involved in the ferroptosis and oxidative phosphorylation pathways. Collectively, These proteins were found to participate mainly in oxidative phosphorylation as well as phosphorylation and metabolic processes in the mitochondria to affect the freezing tolerance of sheep sperm.

Review: The role of male reproductive tract secretions in ruminant fertility

Male fertility largely depends on the ability to produce sperm that can transmit the paternal information onto the next generation. However, the factors that are critical for sperm function and the subsequent development of healthy offspring are still not completely understood in ruminants. Importantly, sperm function is not completely encoded by germ cell DNA, but rather, depends on sequential acquisition, loss, and modification of elements through interaction with secretions from the testes, epididymides, and accessory glands (collectively termed seminal plasma). In addition, these secretions can play a role in the inheritance of paternal environmental effects by progeny. This is likely achieved directly, by the regulation of sperm epigenetic effectors, and indirectly, by altering the female environment in which the individual develops. This review will provide an overview of the different organs that contribute to seminal plasma in ruminants, and summarise how their secretions shape sperm function and modulate the female reproductive tract. Finally, some consideration will be given to the potential of paternal factors to affect embryo development and offspring health in ruminants.

Comparative Analysis of Epididymis Cauda of Yak before and after Sexual Maturity

Epididymis development is the basis of male reproduction and is a crucial site where sperm maturation occurs. In order to further understand the epididymal development of yak and how to regulate sperm maturation, we conducted a multi-omics analysis. We detected 2274 differential genes, 222 differential proteins and 117 co-expression genes in the cauda epididymis of yak before and after sexual maturity by RNA-seq and proteomics techniques, which included TGFBI, COL1A1, COL1A2, COL3A1, COL12A1, SULT2B1, KRT19, and NPC2. These high abundance genes are mainly related to cell growth, differentiation, adhesion and sperm maturation, and are mainly enriched via extracellular matrix receptor interaction, protein differentiation and absorption, and lysosome and estrogen signaling pathways. The abnormal expression of these genes may lead to the retardation of epididymal cauda development and abnormal sperm function in yak. In conclusion, through single and combined analysis, we provided a theoretical basis for the development of the yak epididymal cauda, sperm maturation, and screening of key genes involved in the regulation of male yak reproduction.

Characterization of proteases in the seminal plasma and spermatozoa of llama

Camelids' semen has peculiar characteristics that differentiate it from other species, including the highly viscous aspect of seminal plasma that greatly difficult sperm manipulation and the development of techniques such as cryopreservation, artificial insemination, and/or in vitro fertilization. The presence of proteases in the seminal plasma is responsible for semen liquefaction, and sperm functionality to achieve fertilization. The enzymatic and molecular composition of the semen of llama remains unknown. Therefore, the goal of the study was to characterize the protease activity and composition of the seminal plasma and sperm of llama semen. The proteolytic activity was performed using gelatine zymography and the composition by mass-spectrometry. Metallo-proteases were the major source of gelatinolytic activity in seminal plasma, while serine-peptidases were the main enzymes of sperm cells. Matrix Metalloproteinase 2 (MMP2) was the most prominent metallo-protease of llama seminal plasma characterized under the exposure of different inhibitors (EDTA and benzamidine) and by a specific immunodetection. Moreover, the prostate and epididymis were identified as potential sites of its synthesis and secretion. Outstandingly, this metalloproteinase was undetectable in llama sperm. Regarding, the molecular composition of semen by mass-spectrometry, 4 metallo-, 9 serine-, 8 threonine-, and 1 aspartic-peptidases were identified alongside 15 regulators in the sperm cell; where 24 were directly or indirectly interacting. Whereas 6 metallo-, 12 serine-, 3 cysteine-, and 1 aspartic-peptidases were identified, besides 7 inhibitors and 5 regulators in llama seminal plasma where 30 of them were directly or indirectly interconnected. This is the first study describing a partial degradome of llama seminal plasma and spermatozoa suggesting significant differences especially the absence of MMP2 in spermatozoa in contrast to data observed in other species. The characterization of proteases in llama semen will provide a better understanding of the molecular mechanisms involved in the in vivo or in vitro fertilization process in this species.

Molecular Markers: A New Paradigm in the Prediction of Sperm Freezability

For decades now, sperm cryopreservation has been a pillar of assisted reproduction in animals as well as humans. Nevertheless, the success of cryopreservation varies across species, seasons, and latitudes and even within the same individual. With the dawn of progressive analytical techniques in the field of genomics, proteomics, and metabolomics, new options for a more accurate semen quality assessment have become available. This review summarizes currently available information on specific molecular characteristics of spermatozoa that could predict their cryotolerance before the freezing process. Understanding the changes in sperm biology as a result of their exposure to low temperatures may contribute to the development and implementation of appropriate measures to assure high post-thaw sperm quality. Furthermore, an early prediction of cryotolerance or cryosensitivity may lead to the establishment of customized protocols interconnecting adequate sperm processing procedures, freezing techniques, and cryosupplements that are most feasible for the individual needs of the ejaculate.

DIA mass spectrometry characterizes urinary proteomics in neonatal and adult donkeys

Health monitoring is critical for newborn animals due to their vulnerability to diseases. Urine can be not only a useful and non-invasive tool (free-catch samples) to reflect the physiological status of animals but also to help monitor the progression of diseases. Proteomics involves the study of the whole complement of proteins and peptides, including structure, quantities, functions, variations and interactions. In this study, urinary proteomics of neonatal donkeys were characterized and compared to the profiles of adult donkeys to provide a reference database for healthy neonatal donkeys. The urine samples were collected from male neonatal donkeys on their sixth to tenth days of life (group N) and male adult donkeys aging 4-6 years old (group A). Library-free data-independent acquisition (direct DIA) mass spectrometry-based proteomics were applied to analyze the urinary protein profiles. Total 2179 urinary proteins were identified, and 411 proteins were differentially expressed (P < 0.05) between the two groups. 104 proteins were exclusively expressed in group N including alpha fetoprotein (AFP), peptidase-mitochondrial processing data unit (PMPCB), and upper zone of growth plate and cartilage matrix associated (UCMA), which might be used to monitor the health status of neonatal donkeys. In functional analysis, some differentially expressed proteins were identified related to immune system pathways, which might provide more insight in the immature immunity of neonatal donkeys. To the best of our knowledge, this is the first time to report donkey urinary proteome and our results might provide reference for urinary biomarker discovery used to monitor and evaluate health status of neonatal donkeys.

Proteomics Evaluation of Semen of Clinically Healthy Beagle-Breed Dogs

The objectives of the present work were to evaluate the semen of dogs by means of proteomics methods and to compare with proteomics results of the blood of the animals, in order to increase available knowledge on the topic and present relevant reference values for semen samples. Semen samples were collected from five Beagle-breed dogs. Reproductive assessment of the animals by means of clinical, ultrasonographic and seminological examinations confirmed their reproductive health. The sperm-rich fraction and the prostatic fraction of semen were processed for proteomics evaluation. LC-MS/MS analysis was performed by means of a LTQ Orbitrap Elite system. The technology combines high separation capacity and strong qualitative ability of proteins in biological samples that require deep proteome coverage. Protein classification was performed based on their functional annotations using Gene Ontology (GO). In blood plasma, semen sperm-rich fraction, and semen prostatic fraction, 59, 42 and 43 proteins, respectively, were detected. Two proteins were identified simultaneously in plasma and the semen sperm-rich fraction, 11 proteins in plasma and the semen prostatic fraction, and three proteins in the semen sperm-rich and prostatic fractions. In semen samples, most proteins were related to cell organization and biogenesis, metabolic processes or transport of ions and molecules. Most proteins were located in the cell membrane, the cytosol or the nucleus. Finally, most proteins performed functions related to binding or enzyme regulation. There were no differences between the semen sperm-rich fraction and prostatic fractions in terms of the clustering of proteins. In conclusion, a baseline reference for proteins in the semen of Beagle-breed dogs is provided. These proteins are involved mostly in supporting spermatozoan maturation, survival and motility, enhancing the reproductive performance of male animals. There appears potential for the proteomics examination of semen to become a tool in semen evaluation. This analysis may potentially identify biomarkers for reproductive disorders. This can be particularly useful in stud animals, also given its advantage as a non-invasive method.

Comparative high-throughput analysis of sperm membrane proteins from crossbred bulls with contrasting fertility

The aim of the present study was to identify fertility associated sperm membrane proteins in crossbred bulls. Sperm membrane proteins from high- and low-fertile Holstein Friesian crossbred bulls (n = 3 each) were subjected to high-throughput liquid chromatography-mass spectrometry (LC-MS/MS) for comparative proteomic analysis. Proteomic profiling identified a total of 456 proteins in crossbred bull spermatozoa; it was found that 108 proteins were up regulated while 26 proteins were down regulated (>1.5-folds) in spermatozoa from low- compared to high-fertile bulls. Gene ontology classification revealed that upregulated proteins in low-fertile bulls were involved in biological process such as oxidation-reduction process (p = 3.14E-06), fusion of sperm to egg plasma membrane (p = 7.51E-04), sperm motility (p = 0.03), and capacitation (p = 0.09), while down regulated proteins were associated with transport (p = 6.94E-04), superoxide metabolic process (p = 0.02), and tricarboxylic acid cycle (p = 0.04). KEGG pathway analysis revealed that oxidative phosphorylation and tricarboxylic acid cycle pathways are the most significantly affected pathway in low-fertile bulls. It was concluded that expression of proteins associated with oxidative phosphorylation and tricarboxylic acid cycle pathways were altered in low-fertile crossbred bulls, and expression levels of SPATA19, ELSPBP1, ACRBP, CLU, SUCLA2, and SPATC1 could aid in assessing potential fertility of crossbred bulls.

Structural and biophysical characterization of the major proteins from the seminal plasma of Dorper rams

Pregnancy rates using frozen semen from rams are higher than for horses. One of the factors that positively influences this effect is the composition of low-molecular-weight proteins from seminal plasma, since the amounts of these proteins are much lower in horses. The aim of this work was to purify the major protein components from ram seminal plasma for structural and biophysical characterization. First, the ram semen was collected and the plasma separated by centrifugation. The protein fractions were isolated by gel filtration chromatography, analyzed by circular dichroism spectroscopy and the amino acid sequence identified by mass spectrometry (LC-MS^E), the results of which were used to model the protein structure by bioinformatics techniques. This protein was identified by LC-MS^E as a spermadhesin, being an unglycosylated monomer with T_m = 69.3 °C and ΔH_m= 371 kJ mol^-1 at pH 7.0. This work describes for the first time the structural characterization of a spermadhesin from seminal plasma of Dorper rams.

Matrix metalloproteinase (MMP)-2, MMP-9, semen quality and sperm longevity in fractionated stallion semen

Matrix metalloproteinase (MMP)-2 and MMP-9 are gelatinases that take part in several reproductive processes. The aim of this study was to measure levels of MMP-2 and MMP-9 in fractionated stallion ejaculates, and to evaluate the association between these components and semen quality, and sperm longevity during cooled storage. Semen quality were assessed separately for sperm-rich fractions (HIGH), sperm-poor fractions (LOW), and whole ejaculate samples (WE) from 33 stallions. After cooled storage with SP either present or removed, sperm motility and DFI were determined. The relative activity of the pro-form of MMP-2, active MMP-2 and total MMP-9 were evaluated using gelatin zymography, and all were present in all fractions of the stallion's ejaculate, with higher relative activity of the latent than active forms and the highest relative activity in the HIGH fraction. The relative activities of MMP-2 and MMP-9 were positively correlated to sperm concentration and total sperm count, but only in the HIGH fraction and not in LOW or WE. The relative activities of MMPs were not related to differences in sperm longevity during cooled storage, measured as sperm motility and DFI. There was a harmful effect of SP on DFI during storage, but this effect was not associated with differences in the relative activities of MMPs. In conclusion, the relative activities of MMPs are not useful as markers for semen quality (other than sperm concentration), or sperm survival during storage in horses.

Seasonal differences in seminal plasma proteins from two bovine breeds adapted to a subtropical climate

This study was designed to evaluate the seasonal expression of seminal plasma proteins from two bovine breeds adapted to a subtropical climate and their associations with post-thawing sperm and environmental characteristics. Semen samples were obtained three times in summer and three times in winter from four Crioulo Lageano and four Angus bulls. Seminal plasma was obtained by centrifugation, and the other portion of the semen was cryopreserved. Seminal plasma proteins were identified by 2D-nanoUPLC-MS^E. Post-thawing assessments of sperm kinetics, morphology and membrane integrity were performed. Environmental data such as air temperature, air humidity and black globe temperature (BGT) were recorded, and the temperature-humidity index (THI) was calculated in summer and winter. Results showed that the climate varied significantly between seasons. Although no statistical differences were observed in semen quality between breeds, the protein profiles varied within and between seasons. We suggest that the most critical proteins in summer affecting sperm characteristics were TIMP-2, DNase, Clusterin, CFAH and GPx6. TIMP-2 and DNase showed a higher abundance in Crioulo Lageano in comparison with Angus, while Clusterin, CFAH and GPx6 presented a lower abundance. To the best of our knowledge, this is the first report of a recently evolved type of glutathione peroxidase, GPx6, in seminal plasma of bovines. In winter, five proteins were considered to be more critical: BSP1, BSP3, CCL2, Sulfhydryl oxidase and TIMP-2. BSP1 and TIMP-2 showed a lower abundance while BSP3, CCL2 and Sulfhydryl oxidase presented a higher abundance in this season in Crioulo Lageano in comparison with Angus.

Еffect of different breeds on the protein profile in ram seminal plasma

In this study the individual profiles of seminal plasma proteins (SPP) in rams of three breeds – Merino, Pleven Blackhead and Ile de France - were analysed. The study was carried out with three rams at 3, 6 and 10 years of age, grown and fed under similar conditions. Eighteen ejaculates (6 ejaculates from each ram) were evaluated by Sperm Class Analyzer. The total SPP concentration was measured spectrophotometrically. The separation and characterisation of SPP was performed by HPLC and one dimensional polyacrylamide gel electrophoresis (SDS-PAGE). There were no significant differences between the characteristics of ejaculates and the main kinematic parameters of the sperm in the breeds studied. Chromatograms showed specific profiles with 9, 10 and 11 protein peaks for Merino, Pleven Blackhead and Ile de France breeds, respectively. The total SPP concentration was the highest in the Pleven Blackhead breed and the lowest in Ile de France breed. The major parts of SPP in the three breeds were identical. The seminal plasma of Merino breed contained proteins with molecular mass of 30.3 kDa, 15.7 kDa and 15.2 kDa that were not present in the other two breeds. In the Ile de France and Pleven Blackhead samples only, two proteins with molecular masses of 39.7 kDa and 21.1 kDa, were observed. In conclusion, the detection of specific proteins can be used as a biological marker for sheep breed identification.

The proteomic characterization of ram sperm during cryopreservation analyzed by the two-dimensional electrophoresis coupled with mass spectrometry

The aim of this study was to analyze the effects of the cryopreservation process on the protein profile of ram sperm using two-dimensional electrophoresis (2-DE) coupled with mass spectroscopy. Semen was collected from five rams and cryopreserved in a Tris-based extender supplemented with glycerol and egg yolk as the main cryoprotectants. The fresh and post-thaw sperm total proteins were extracted and purified, followed by the 2-DE. The differential proteins in the stained gel were determined by mass spectrometry. The results indicated that there were 39 differential proteins between fresh sperm and frozen-thawed sperm. Among these proteins, the abundance of 28 proteins in fresh sperm was higher than those in post-thaw sperm (P < 0.05). However, 11 proteins in post-thaw sperm were up-regulated instead. The gene ontology (GO) analysis showed that most of differential proteins were implicated in cellular process, metabolism and regulation of the biological process. The networks of protein-protein interaction indicated a strong interaction among these differential proteins, which may be involved in sperm metabolism, acrosomal function, sperm motility, and reducing ROS level. In conclusion, the cryopreservation process modifies the proteome of ram sperm, which may be directly associated with ram sperm cryodamage, consequently influencing their fertility. Additionally, these differential proteins can be used as biomarkers for evaluation of frozen ram semen quality.

Mapping the major proteome of reproductive fluids and sperm membranes of rams: From the cauda epididymis to ejaculation

The present study evaluated the major proteome of ram seminal plasma and the main secretions that contribute to its formation, such as the cauda epididymal and accessory sex gland fluids. The study also investigated sperm membrane protein profiles before and after ejaculation. First, semen was collected from six rams (using artificial vagina) to obtain seminal plasma and ejaculated sperm. Then, rams were vasectomized for collection of accessory sex gland fluid (using artificial vagina). Next, rams were slaughtered and cauda epididymal fluid (CEF), seminal vesicle fluid, bulbourethral gland fluid and cauda epididymal sperm were properly collected. Proteins from reproductive fluids and sperm membranes were analyzed by 2-D SDS-PAGE, tandem mass spectrometry and bioinformatics. There we 386 proteins and 256 isoforms identified in all samples. The most abundant seminal plasma proteins were BSP1, BSP5 and spermadhesins (bodhesin-2 and spermadhesin Z13-like). These proteins were present in similar patterns in maps of accessory sexgland fluid, with very low quantities in the CEF and absent in the bulbourethral gland secretion. Thus, practically all BSPs and spermadhesins come from seminal vesicles. Bulbourethral gland fluid brought bactericidal/permeability-increasing protein-containing Family A member 1 isoforms, superoxide dismutase [Cu-Zn] and betamicroseminoprotein to seminal plasma. CEF was the major provider of clusterin, epididymal-specific lipocalin-5-like isoform, epididymal secretory gluthathione peroxidase, epididymal secretory protein E1 and prostaglandin-H2 D-isomerase to seminal plasma. Albumin came from all reproductive fluids. BSPs and spermadhesins were present in 2-D maps of ejaculated sperm but absent in cauda epididymal sperm. These proteins come from the seminal vesicles and bind to sperm at the moment of ejaculation. Other proteins of ejaculated and epididymal sperm membranes were mostly associated to energy production, cell adhesion and proteolytic activity (ATP synthases, disintegrin, metalloproteinase domain-containing protein 32, carboxypeptidase Q and cytosol aminopeptidase). In conclusion, there is a well-orchestrated sequence of events to form the major seminal plasma proteome, with specific contributions from cauda epididymis, seminal vesicles and bulbourethral glands. The present data contribute to a better understanding of male reproductive biology and how sperm functions are affected by the noncellularmicro environment of semen.

Protein signatures of seminal plasma from bulls with contrasting frozen-thawed sperm viability

The present study investigated the seminal plasma proteome of Holstein bulls with low (LF; n = 6) and high (HF; n = 8) sperm freezability. The percentage of viable frozen-thawed sperm (%ViableSperm) determined by flow cytometry varied from -2.2 in LF to + 7.8 in HF bulls, as compared to the average %ViableSperm (54.7%) measured in an 860-sire population. Seminal proteins were analyzed by label free mass spectrometry, with the support of statistical and bioinformatics analyses. This approach identified 1,445 proteins, associated with protein folding, cell-cell adhesion, NADH dehydrogenase activity, ATP-binding, proteasome complex, among other processes. There were 338 seminal proteins differentially expressed (p < 0.05) in LF and HF bulls. Based on multivariate analysis, BSP5 and seminal ribonuclease defined the HF phenotype, while spermadhesin-1, gelsolin, tubulins, glyceraldehyde-3-phosphate dehydrogenase, calmodulin, ATP synthase, sperm equatorial segment protein 1, peroxiredoxin-5, secretoglobin family 1D and glucose-6-phosphate isomerase characterized the LF phenotype. Regression models indicated that %ViableSperm of bulls was related to seminal plasma peroxiredoxin-5, spermadhesin-1 and the spermadhesin-1 × BSP5 interaction (R2 = 0.84 and 0.79; p < 0.05). This report is the largest dataset of bovine seminal plasma proteins. Specific proteins of the non-cellular microenvironment of semen are potential markers of sperm cryotolerance.

Equine seminal plasma and sperm membrane: Functional proteomic assessment

During ejaculation, a large amount of seminal plasma proteins interact with the sperm membrane, leading to a series of biochemical and structural changes implicated in sperm function and gamete interaction. However, the roles of the majority of these proteins remain unknown. This study aimed to investigate the proteome and functionality of the major equine proteins of seminal plasma and the sperm membrane. Seminal plasma and enriched-membrane proteins (150 μg) were separated by two-dimensional gel electrophoresis, and the respective maps were analyzed. Protein identification was performed by in-gel digestion and tandem mass spectrometry (GeLC-MS/MS). Samples were also submitted to in-solution digestion (complex protein mixture) and identified by shotgun analysis by LC-MS/MS; bioinformatic tools were used to investigate protein functions. Seminal plasma and sperm membrane extract maps contained 91.0 ± 8.2 spots and 245.3 ± 11.3 spots, respectively, within the 3-10 pH range. In total, the most abundant proteins identified in 2D maps and in complex protein mixtures included 24 proteins for seminal plasma and 33 for sperm membrane extract, with a high degree of confidence (P < 0.05). Of these, HSP1, CRISP3 and KLK1E2 were the most abundant in seminal plasma; HSP1 was highly abundant in sperm membrane extract, in many isoforms, which is related to membrane destabilization and may compromise sperm preservation. HSP1-polybromo-1 interactions suggested a role in DNA stabilization. Prosaposin was identified in seminal plasma and may play a role in the fertilization process. IZUMO4, a member of the IgSF family involved in the prefertilization stages, was identified in 2D gel and MS/MS analysis of sperm membrane extract. Ten proteins of seminal plasma were found to interact with the sperm membrane and were related to binding and catalytic activities (clusterin, CRISP3, epididymal sperm-binding protein 1, kallikrein1E2, seminal plasma protein A3, and HSP1). Additionally, other identified proteins were associated with DNA integrity, capacitation and recognition of pregnancy. These findings indicate that the binding of specific proteins to the plasma membrane during ejaculation may influence sperm survival after cryopreservation and may play a role in decreasing the quality in stallions with toxic seminal plasma. Elucidation of these interactions is an important step in understanding the biological processes related to equine fertility and facilitates future investigations on the selection and application of low freezability semen strategies.

Effects of Organic Selenium on the Physiological Response, Blood Metabolites, Redox Status, Semen Quality, and Fertility of Rabbit Bucks Kept Under Natural Heat Stress Conditions

Heat stress can impair the general health of rabbit bucks by disturbing physiological homeostasis with negative consequences in animal welfare and remarkable decline in reproductive performance. Selenium (Se) can control a number of vital biological processes. Thus, the effects of organic selenium (OSe) supplementation on the blood metabolites, redox status, semen quality, testicular histology, seminal plasma protein profile, and fertility of rabbit bucks kept under natural heat stress conditions were studied. Adult V-line male rabbits were fed a basal diet supplemented with 0.3 mg OSe/kg dry matter (DM) diet (OSe, n = 9) or not (control, CON, n = 9) for 12 weeks. The results showed that rabbits fed the OSe diet had 73.68 and 68.75% higher (P < 0.05) OSe concentrations in the blood serum and seminal plasma, respectively, than rabbits fed the CON diet. The OSe diet significantly decreased the rectal temperature and respiration rate and significantly increased the blood serum concentrations of total protein, albumin, glucose, and glutathione peroxidase compared to the CON diet. Rabbits fed the OSe diet had lower reaction times (12.53 vs. 5.84 s, ± 0.79, P < 0.01) and higher total functional sperm counts (116.74 vs. 335.23 × 10⁶/ml, ± 24.68, P < 0.001) and percentages of integrated sperm membranes (60.38 vs. 79.19%, ± 1.69, P < 0.01) than rabbits fed the CON diet. Rabbits fed the OSe diet had higher (P < 0.01) contents of seminal plasma total protein, albumin, alanine transaminase, fructose, and total antioxidant capacity and lower (P < 0.001) malondialdehyde (MDA) levels than those fed the CON diet. Rabbits fed the OSe diet had sperm cells with higher levels of integrated DNA than those fed the CON diet. The seminal plasma of rabbits fed the OSe diet contained four new proteins, with molecular weights of 19.0, 21.5, 30.0, and 44.0 kDa. The kindling rates, litter size, and weight at birth of females mated with males fed the OSe diet were significantly higher than those of females mated with males fed the CON diet. In summary, the inclusion of 0.3 mg OSe/kg DM diet of naturally heat-stressed rabbit bucks countered the negative impacts of elevated environmental temperature on physiological homeostasis, semen quality, and fertility.

Untargeted metabolomic profiling of accessory sex gland fluid from Morada Nova rams

The present study was conducted to characterize the metabolome of accessory gland fluid (AGF) of locally adapted Morada Nova rams, raised in the Brazilian Northeast. AGF was collected by an artificial vagina from five vasectomized rams. Metabolites were identified by gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography-mass spectrometry (LC/MS), with the support of Human Metabolome Database, PubChem, LIPID Metabolites, Pathways Strategy databases, and MetaboAnalyst platforms. There were 182 and 190 metabolites detected by GC/MS and LC/MS, respectively, with an overlap of one molecule. Lipids and lipid-like molecules were the most abundant class of metabolites in the ram AGF (127 compounds), followed by amino acids, peptides, and analogs(103 metabolites). Considering all GC/MS and LC/MS, fructose, glycerol, citric acid, d-mannitol, d-glucose, and l-(+)-lactic acid were the most abundant single metabolites present in the ram AGF. Meaningful pathways associated with AGF metabolites included glycine, serine and threonine metabolism; pantothenate and CoA biosynthesis; galactose metabolism; glutamate metabolism and phenylalanine metabolism, and so forth. In conclusion, the combined use of LC/MS and GC/MS was essential for getting a holistic view of the compounds embedded in the ram AGF. Chemical analysis of the accessory sex gland secretion is relevant for understanding sperm function and fertilization.

Effects of increased scrotal temperature on semen quality and seminal plasma proteins in Brahman bulls

Environmental temperature has effects on sperm quality with differences in susceptibility between cattle subspecies and breeds, but very little is known about the seminal plasma protein (SPP) changes resulting from testicular heat stress. Scrotal insulation (SI) for 48 hr was applied to Brahman (Bos indicus) bulls. Semen was collected at 3-day intervals from before, until 74 days post-SI. The changes in sperm morphology and motility following SI were comparable to previously reported and differences were detected in measures of sperm chromatin conformation as early as 8 days post-SI. New proteins spots, in the SPP two-dimensional (2-D) gels, were apparent when comparing pre-SI with 74 days post-SI, and SPP identified as associated with mechanisms of cellular repair and protection. Similar trends between 2-D gel and Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) data was observed, with SWATH-MS able to quantify individual SPP that otherwise were not resolved on 2-D gel. The SPP assessment at peak sperm damage (21-24 days) showed a significant difference in 29 SPP (adjusted p < .05), and identified six proteins with change in abundance in the SI group. In conclusion both spermatozoa and SPP composition of bulls are susceptible to temperature change incurred by SI, and SPP markers for testicular heat insults may be detected.

Cross comparison of seminal plasma proteins from cattle and buffalo (Bubalus bubalis)

The objective of this study was to evaluate seminal plasma proteins from cattle and buffalo (Bubalus bubalis), to identify differences between related species. Sixteen buffaloes and 16 cattle between 30 and 60 months of age were used. Semen collection was performed by electroejaculation, followed by macroscopic and microscopic subjective analyses. After analysis, the samples were centrifuged at 800 g for 10 min, and the supernatant (seminal plasma) was recentrifuged at 10,000 g for 30 min at 4°C. The total protein concentration was determined by the Bradford method, and the proteins were digested in solution for mass spectrometry (nLC-MS/MS). Multivariate statistical analysis was used to evaluate the proteomics results by non-hierarchical clustering the considering exponentially modified protein abundance index (emPAI). Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used for clustering. Proteomics identified 78 proteins, and multivariate analysis showed 4 that were over-expressed in buffaloes (cystatin C, prosaposin, peptide YY and keratin type II cytoskeletal 5) and 9 in cattle (spermadhesin-1, seminal plasma protein PDC-109, ribonuclease 4, metalloproteinase inhibitor 2, acrosin inhibitor 1, seminal ribonuclease, C-type natriuretic peptide, angiogenin-1 and osteopontin). Among the proteins identified in seminal plasma, the C-type natriuretic peptide and metalloproteinase inhibitors were described for the first time in buffaloes. Some protease inhibitors were found over-expressed in buffaloes, and important proteins in seminal plasma of cattle were not identified or were found at lower expression levels in buffaloes, which can contribute to reproductive performance in this species.

Proteome of cat semen obtained after urethral catheterization

The binding of seminal plasma (SP) proteins by spermatozoa plays an important role in the regulation of sperm epididymal maturation, motility gaining in female reproductive tracts and sperm-egg interaction. The aim of the study was to analyze the SP and sperm extracts proteome of cat (Felis catus) semen. The seminal plasma and spermatozoa were obtained by urethra catheterization from 10 male cats. Proteins were extracted using RIPA buffer and separated by electrophoresis (SDS-PAGE). The gels were analyzed using MultiAnalyst software. The proteins were subsequently analyzed using NanoUPLC-Q-TOF/MS. UniProt database-supported identification resulted in 106 proteins identified in the cat SP and 98 proteins in the extracts of spermatozoa. Based on a gene ontology analysis, dominant molecular functions of feline SP proteins were binding, catalytic, and antioxidant activity (56%, 33%, and 11% of cases, respectively). The molecular functions of sperm extracts proteins were mainly involved in catalytic activity (41%) and binding (23%). The proteins present in both, the SP and spermatozoa's extracts, were: serum albumin (ALB), semenogelin 2 (SEMG 2), clusterin (CLU), lactoferrin (LTF), prostatic acid phosphatase (ACPP), prolactin inducible protein (PIP), negative elongation factor E (NELF-E) and ectonucleotide pyrophosphatase (ENPP3). Protein-protein interactions analysis showed significant connection for 12 proteins in the cat semen. The seminal plasma proteins which, with high probability score, participate in important metabolic pathways are: glutathione peroxidases (GPx5 and 6), prostatic acid phosphatase (ACPP), β-hexosaminidase (HEXB), polymeric immunoglobulin receptor (pIgR) and serpin family F member 1 (SERPINF1). For sperm protein extracts it were: pyruvate dehydrogenase (PDHB), succinate-CoA-ligase (SUCLA2), malate dehydrogenase (MDH2), ATP synthase F1 subunit alpha (ATP5F1A) and tubulin beta (TUBB).

The expression of the new epididymal luminal protein of PDZ domain containing 1 is decreased in asthenozoospermia

Spermatozoa are not mature until they transit the epididymis where they acquire motility and the ability to fertilize an egg through sequential modifications. The epididymis has three functional regions, caput, corpus, and cauda, and the luminal proteins of the epididymis play important roles in the above modifications. However, the proteins with differential enrichment between the caput and cauda are still largely unknown. To reveal the functions of the caput and cauda during sperm maturation, luminal proteins from caput and cauda of mice were analyzed by isobaric tag for relative and absolute quantitation (iTRAQ). Overall, 128 differentially enriched proteins were found, of which 46 were caput enriched and 82 were cauda enriched. Bioinformatic analysis showed that lipid metabolism was active in the caput; while anion- and cation-binding activity and phosphorus and organophosphate metabolism were active in the cauda. A new epididymal luminal protein, the caput-enriched PDZ domain containing 1 (Pdzk1), also named Na⁺/H⁺ exchange regulatory cofactor 3 (NHERF3), which plays a critical role in cholesterol metabolism and carnitine transport, was found in the lipid metabolism. Western blotting and immunofluorescence analyses showed that Pdzk1 was expressed in the epididymis but not in the testis, and localized at the middle piece of the sperm tail. Pdzk1 protein level was also reduced in the spermatozoa in case of asthenozoospermic patients compared with that in normozoospermic men, suggesting that Pdzk1 may participate in sperm maturation regulation and may be associated with male infertility. These results may provide new insights into the mechanisms of sperm maturation and male infertility.

Major seminal plasma proteome of rabbits and associations with sperm quality

The present study was conducted to describe the major seminal plasma proteome of rabbits and potential associations between seminal proteins and semen criteria. Semen samples were collected from 18 New Zealand adult rabbits, and seminal plasma proteins were analyzed by 2-D SDS-PAGE and tandem mass spectrometry. Sperm motility, vigor, concentration, morphology and membrane sperm viability were evaluated. Rabbits ejaculated 364 ± 70 million sperm/ml, with 81 ± 6.1% motile cells, 3.8 ± 0.2 vigor and 66.7 ± 2.5% sperm with normal morphology. Based on the viability and acrosome integrity assay, there were 65.8 ± 2.5% live sperm with intact acrosome and most spermatozoa had both intact acrosome and functional membrane. On average, 2-D gels of rabbit seminal plasma had 232 ± 69.5 spots, as determined by PDQuest software (Bio Rad, USA). Mass spectrometry allowed the identification of 137 different proteins. The most abundant proteins in rabbit seminal plasma were hemoglobin subunit zeta-like, annexins, lipocalin, FAM115 protein and albumin. The intensity of the spots associated with these five proteins represented 71.5% of the intensity of all spots detected in the master gel. Multiple regression models were estimated using sperm traits as dependent variables and seminal plasma proteins as independent ones. Also, sperm motility had positive association with beta-nerve growth factor and cysteine-rich secretory protein 1-like and a negative one with galectin-1. The percentage of rabbit sperm with intact membrane was related to seminal plasma protein FAM115 complex and tropomyosin. Then, the population of morphologically normal sperm in rabbit semen was positively linked to carcinoembryonic antigen-related cell adhesion molecule 6-like and down regulated by seminal plasma isocitrate dehydrogenase. Based on another regression model, the variation in the percentage of live sperm with intact acrosome was partially explained by the amount of leukocyte elastase inhibitor and the peptidyl-prolyl cis-trans isomerase A in the rabbit seminal fluid. The current study reports the identification of 137 proteins of rabbit seminal plasma. Major proteins of seminal secretion relate primarily to prevention of damages caused by lipid peroxide radicals and oxidative stress, membrane functionality, transport of lipids to the sperm membrane and temperature regulation. Moreover, finding seminal plasma proteins as indicators of semen parameters will improve assisted reproductive technologies.

Gene and protein expression in the reproductive tract of Brazilian Somalis rams

Brazilian Somalis is a locally-adapted breed of rams raised in tropical climate and native pastures. The present study was conducted to evaluate gene expression and proteome of the reproductive tract of such rams. Samples were collected from testes, epididymides, seminal vesicles and bulbourethral glands of four rams. Expression of clusterin (CLU), osteopontin (OPN) and prostaglandin D2 synthase (PGDS) genes were evaluated in all samples by real-time PCR. Shotgun proteomic analysis was performed using samples from the head, corpus and cauda epididymides and from all other structures as well. Gene ontology terms and protein interactions were obtained from UniProtKB databases and MetaCore v.6.8 platform. CLU trasncripts were detected in the testes, epididymides, seminal vesicles and bulbourethral glands of the Somalis rams. The initial region and body of the epididymis had the greatest CLU expression. OPN mRNA was localized in all tissues of the ram reproductive tract. PGDS mRNA was detected in the testes and epididymides. Lable-free mass spectrometry allowed the identification of 137 proteins in all samples. Proteins of the epididymis head mainly participate in cellular processes and response to stimulus, participating in catalityc activity and binding. Proteins of epididymis body acted as regulatory proteins and in cellular processes, with binding and catalytic activity. Cauda epididymis molecules were associated with cellular processes and regulation, with binding function and catalytic activity as well. Testis proteins were mainly linked to cell processes and response to stimuli, and had catalytic function. Seminal vesicle proteins were involved in regulation and mainly with binding functions. Most bulbourethral gland proteins participated in cellular processes. The present study is the first to evaluate the proteome and gene expressions in the reproductive tract of Brazilian Somalis rams. Such pieces of information bring significant cointribution for the understanding of the reproductive physiology of locally-adapted livestock.

Label-free proteome of water buffalo (Bubalus bubalis) seminal plasma

The study aimed to describe the Bubalus bubalis seminal plasma proteome using a label-free shotgun UDMS^E approach. A total of 859 nonredundant proteins were identified across five biological replicates with stringent identification. Proteins specifically related to sperm maturation and protection, capacitation, fertilization and metabolic activity were detected in the buffalo seminal fluid. In conclusion, we provide a comprehensive proteomic profile of buffalo seminal plasma, which establishes a foundation for further studies designed to understand regulation of sperm function and discovery of novel biomarkers for fertility. MS data are available in the ProteomeXchange with identifier PXD003728.

Proteomic identification of turkey (Meleagris gallopavo) seminal plasma proteins

SDS-PAGE combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and 2-dimensional electrophoresis (2DE) combined with matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry (MALDI TOF/TOF) were applied to characterize the turkey seminal plasma proteome. LC-MS/MS led to the identification of 175 proteins, which were classified according to their function and to corresponding biochemical pathways. Using 2DE and MALDI TOF/TOF, 34 different turkey seminal plasma proteins could be identified, of which 20 were found in more than one spot, indicating different proteoforms of these proteins. For validation, antibodies against turkey albumin and ovoinhibitor as well as sperm acrosin were used in 2DE Western blots experiments. The bioinformatic analysis of the results indicates that turkey seminal plasma proteins may be involved in regulation of lipid metabolism [liver X receptor/retinoid X receptor (LXR/RXR) activation and farnesoid X receptor/retinoid X receptor (FXR/RXR) activation pathways)], endocytic entry of proteins and lipids at the plasma membrane (clathrin-mediated endocytosis pathway), and defense against pathogens (acute phase response signaling pathway) and energy production (glycolysis and gluconeogenesis). Moreover, a comparative meta-analysis of seminal plasma proteomes from other species indicated the presence of proteins specific for avian reproduction, but distinct differences between turkey and chicken seminal plasma proteomes were detected. The results of our study provide basic knowledge of the protein composition of turkey seminal plasma highlighting important physiological pathways which may play crucial roles in the sperm environment after ejaculation. This knowledge can be the basis to further develop procedures improving the reproduction of farmed turkeys.

Seminal plasma and sperm proteome of ring-tailed coatis (Nasua nasua, Linnaeus, 1766)

Ring-tailed coati is listed as a species of least concern in the International Union for Conservation of Nature (IUCN) Red List, however, there has been a sharp decline in their population. The present study was conducted to evaluate the major proteins of both seminal plasma and sperm in ring-tailed coatis. Semen sample was collected from three adult coatis and evaluated for their morphological characteristics. Further, the sample was centrifuged to separate spermatozoa from seminal plasma, and then stored in liquid nitrogen. The seminal plasma and sperm proteins were subjected to one-dimensional (1-D) sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and identified by mass spectrometry. Gene ontology and protein networks were analyzed using bioinformatics tools. Based on sperm concentration and average protein content of the semen, the concentration of protein/spermatozoon was found to be 104.69 ± 44.43 μg. The analysis of SDS-PAGE gels showed 20.3 ± 3.1 and 17 ± 2 protein bands/lane for seminal plasma and sperm, respectively. In-gel protein digestion and peptide analysis by mass spectrometry revealed 238 and 246 proteins in the seminal plasma and sperm, respectively. The gene ontology analysis revealed that the proteins of seminal plasma mainly participated in cellular (35%) and regulatory (21%) processes. According to their cellular localization, seminal plasma proteins were categorized as structural (18%), extracellular (17%), and nuclear (14%) proteins with molecular functions, such as catalytic activity (43%) and binding (43%). The sperm proteins were also involved in cellular (38%) and regulatory (23%) processes, and mainly categorized as extracellular (17%), nuclear (13%), and cytoplasmic (10%) proteins. The major molecular functions of the sperm proteins were catalytic activity (44%) and binding (42%). These results indicated that the seminal plasma of ring-tailed coati has an array of proteins that can potentially modulate several sperm functions, from sperm protection to oocyte binding. However, further studies are necessary to interpret the roles of these major seminal plasma proteins in coatis.

Rabbit seminal plasma proteome: The importance of the genetic origin

The present study was conducted to characterise rabbit seminal plasma proteins (SP proteins) focusing on the influence of the genetic origin and seasonality. In addition, β-NGF protein quantity in SP was determined. Semen samples were recovered from January to December 2014 using 6 males belonging to genotype A and six from genotype R. For each genotype, one pooled sample at the beginning, middle and end of each season was selected to develop the experiment. A total of 24 pools (3 for each season and genetic line) were analysed. SP proteins of the two experimental groups were recovered and subjected to in-solution digestion nano LC-MS/MS and bioinformatics analysis. The resulting library included 402 identified proteins validated with ≥95% Confidence (unused Score ≥ 1.3). These data are available via ProteomeXchange with identifier PXD006308. Only 6 proteins were specifically implicated in reproductive processes according to Gene Ontology annotation. Twenty-three proteins were differentially expressed between genotypes, 11 over-expressed in genotype A and 12 in genotype R. Regarding the effect of season on rabbit SP proteome, results showed that there is no clear pattern of protein variation throughout the year. Similar β-NGF relative quantity was observed between seasons and genotypes. In conclusion, this study generates the largest library of SP proteins reported to date in rabbits and provides evidence that genotype is related to a specific abundance of SP proteins.

Pattern of protein expression in the epididymis of Oligoryzomys nigripes (Cricetidae, Sigmodontinae)

In the epididymis, epithelial cells work in a concerted manner to create a luminal environment for sperm maturation, transport, and storage. However, the cell functions may be affected by anthropogenic factors, causing negative impacts on male fertility. In our study, we describe the pattern of protein expression in the epithelium and luminal fluid from epididymis of Oligoryzomys nigripes, a South American sigmodontine rodent whose reproductive biology has been little studied. Nine animals were captured from a preserved area of Atlantic Forest, where the exposure to anthropogenic influences is minimal. Epididymides were processed for histological analysis under light and epifluorescence microscopy, in which we used cell-specific markers aquaporin 9 (AQP9), vacuolar H⁺-ATPase (V-ATPase), and cytokeratin 5 (KRT5). Other samples were assessed for protein expression using shotgun proteomics. Similar to laboratory rodents, principal cells expressed AQP9 in their stereocilia. Basal cells, identified by KRT5 labeling, presented lateral body projections and a few axiopodia going toward the lumen. Clear cells expressed V-ATPase in their sub-apical vesicles and microplicae, and showed different shapes along the duct. Shotgun proteomics detected 51 proteins from epididymal supernatant. Most of them have been previously described in other species, indicating that they are well conserved. Twenty-three proteins detected in O. nigripes have not been described in epididymis from other South American sigmodontine rodents, confirming that the secretion pattern is species-specific. Our findings in O. nigripes from a protected area may help to create a baseline for studies investigating the effects of anthropogenic factors on functionality of the epididymal epithelium.

Sperm membrane proteins associated with the boar semen cryopreservation

This study aimed to define sperm membrane protein markers of semen freezability of boars with the aid of a proteomic approach. Semen from fourteen adult boars were subjected to slow freezing and rapid thawing. After thawing, sperm vigor and motility were analyzed, and based on these results, animals were separated into two groups: good (GFEs) and poor freezability (PFEs). Sperm membrane proteins were extracted and subjected to two-dimensional electrophoresis. Stained gels were analyzed by computerized resources to indicate differentially expressed protein spots, that were identified by mass spectrometry. Six animals showed good freezability with average sperm vigor and motility of 2.2±0.8 and 41.8±22.9, respectively, whereas eight boars showed poor freezability, with 1.9±0.6 and 26.8±17.5 of sperm vigor sperm motility, respectively. An average of 263±62.2 spots per gel and 234.2±54.6 of spots consistently present in all gels were detected. The intensities of five spots were significantly different between groups. Fc fragment of IgG binding protein and lactadherin were more intense in the PFE group, while Arylsulfatase A and F-actin capping protein subunit alpha 1 were more expressed in the GEF group. Based on their functions and interactions with other proteins, we conclude that these four sperm membrane proteins may act as potential markers of boar semen freezability.

Variation in seminal plasma alters the ability of ram spermatozoa to survive cryopreservation

Variation in the effect of seminal plasma on sperm function and fertility has been hypothesised to be due to differences between males and their seminal plasma composition. The freezing resilience of individual rams (n=17) was investigated to characterise inter-male variation. This was determined by measuring the degree of change in motility induced by cryopreservation (Experiment 1). Experiment 2 examined the effect of pooled seminal plasma from rams identified as having high or low resilience to freezing on the cryosurvival of washed spermatozoa from either high (n=3) or low (n=3) sperm freezing resilience rams. Immediately after thawing and throughout the incubation period (0-4h), spermatozoa from high-resilience rams frozen with high-resilience seminal plasma demonstrated superior motility to spermatozoa from high-resilience rams frozen with low-resilience seminal plasma (P<0.001). Similarly, spermatozoa from low-resilience rams frozen with high-resilience seminal plasma exhibited higher motility than spermatozoa from low-resilience rams frozen with low-resilience seminal plasma immediately after thawing (0h; P<0.001). The present study shows that variation in freezing resilience of ram spermatozoa is related to the source and composition of the seminal plasma.

Proteomic characterization of canine seminal plasma

The present study was conducted to identify the major proteome of the sperm-rich fraction and prostatic fraction of canine seminal plasma. Three semen samples from four healthy dogs were obtained by digital manipulation. The pre-sperm fraction, sperm-rich fraction and prostatic fraction were separated from each ejaculate. Immediately after sperm analysis, a protease inhibitor was added to the sperm-rich fraction and prostatic fraction, and the fractions were separately centrifuged and frozen at -80 °C. The samples were thawed, re-centrifuged, and the total protein concentration was determined. Samples were subjected to 1D SDS-PAGE and Coomassie-blue stained gels, were analyzed by Quantity One 1D Analysis Software. Bands detected in the gels were excised and proteins subjected to digestion with trypsin. Proteins were identified by nano-HPLC-MS and tools of bioinformatics. Tandem mass spectrometry allowed the detection of 268 proteins in the gels of sperm-rich fraction and prostatic fraction of canine ejaculate. A total of 251 proteins were common to the sperm-rich and prostatic fractions, while 17 proteins were present in the sperm-rich fraction and absent in the prostatic fraction. The intensity of the bands detected in range 1 and 2 represented 46.5% of all of the band intensities detected in the 1D gels for proteins of the sperm-rich fraction and 53.0% of all bands in the prostatic fraction. Arginine esterase and lactotransferrin precursor were the protein with the highest intensity observed in the both fractions. Among the proteins present only in the sperm-rich fraction, the proteins UPF0764 protein C16orf89 homolog and epididymal-specific lipocalin-9 were the most abundant. In conclusion, canine sperm-rich fraction and prostatic fraction express a very diverse set of proteins, with unique biochemical properties and functions. Moreover, although most proteins are common to both sperm-rich fraction and prostatic fraction, there are some exclusive proteins in sperm-rich fraction.

Physical evaluation, morphological and identification of seminal proteins in Santa Ines sheep

SUMMARY This study aimed to identify proteins in the seminal plasma associated with fertility in sheep of Santa Inês in Manaus, AM, using twodimensional electrophoresis techniques associated with mass spectrometry. Semen samples from eight adult sheep were collected by removing an aliquot for the physical and morphological assessments of semen and seminal plasma was subjected to SDS-PAGE profile and two-dimensional electrophoresis. Gels were stained with colloidal Coomassie, scanned and analyzed using ImageMaster 2D Platinum software, version 6.0. The selected individual spots were cut from the master gel, digested with trypsin and subjected to identification by mass spectrometry (MALDITof / Tof). Of the 108 spots detected in the gel, it selected 10 differential spots (based on the distribution thereof in the bidimensional gel and pre-analysis of the 2D ImageMaster Platinum Software) identifying 03 proteins: clusterin, a protein 14-3-3 zeta chain and Ram Seminal versicles 22kDa Protein. The identity of these proteins implies that the components of seminal plasma participate in physiological processes involved in sperm protection, motility and sperm capacitation, all associated with fertility. These proteins need to be better studied to see whether the same could be used as molecular markers of fertility as they were also found in other studies conducted with sheep Santa Ines.

Proteomic Investigation of Ram Spermatozoa and the Proteins Conferred by Seminal Plasma

Sperm proteomes have emerged for several species; however, the extent of species similarity is unknown. Sheep are an important agricultural species for which a comprehensive sperm proteome has not been produced. In addition, potential proteomic factors from seminal plasma that may contribute to improved fertility after cervical insemination are yet to be explored. Here we use liquid chromatography-tandem mass spectrometry to investigate the proteome of ejaculated ram spermatozoa, with quantitative comparison to epididymal spermatozoa. We also present a comparison to published proteomes of five other species. We identified 685 proteins in ejaculated ram spermatozoa, with the most abundant proteins involved in metabolic pathways. Only 5% of ram sperm proteins were not detected in other species, which suggest highly conserved structures and pathways. Of the proteins present in both epididymal and ejaculated ram spermatozoa, 7% were more abundant in ejaculated spermatozoa. Only two membrane-bound proteins were detected solely in ejaculated sperm lysates: liver enriched gene 1 (LEG1/C6orf58) and epidermal growth factor-like repeats and discoidin I-like domains 3 (EDIL3). This is the first evidence that despite its relatively complex proteomic composition, seminal plasma exposure leads to few novel proteins binding tightly to the ram sperm plasma membrane.

Gelatin Binding Proteins in Reproductive Physiology

In order to advance the assisted reproductive technologies used in animals and human beings, it is important to accumulate basic informations about underlying molecular mechanisms that shape the biological processes of reproduction. From within seminal plasma, proteins perform a wide variety of distinct functions that regulate major reproductive events such as fertilization. The ability of such proteins to bind and interact with different antagonistic ions and biomolecules such as polysaccharides, lipids, and other proteins present in the male and female reproductive tract define these capabilities. Over the last two decades, extensive work has been undertaken in an attempt to define the role of seminal plasma proteins, of which, Gelatin binding proteins (GBPs) represent a large family. GBPs comprise of known group of Bovine seminal plasma (BSP) protein family, matrix metallo proteinases (MMP 2 and MMP 9) and fibronectin, which have been widely studied. The presence of a type II repeat is a characteristic feature of GBPs, which is similar in structure to the fibronectin type II domain (fn2), which has ability to bind multiple ligands including gelatin, glycosaminoglycans, choline phospholipids, and lipoproteins. Two fn2 domains are present within the BSP protein family, while, three fn2 domains are found in gelatinases (MMP-2 and MMP9), and ELSPBP1 (Epididymosomes Transfer Epididymal Sperm Binding Protein 1) contains four long fn2 domains. For the most part BSP proteins are exclusively expressed in seminal vesicles although mBSPH1, mBSPH2 and hBSPH1 are all expressed in the epididymis. The expression of gelatinases has been demonstrated in several organs and tissues such as the prostate, testis, epididymis, ovary, human placenta, cervix and endometrial wall. This review intends to bring current updates on the role of GBPs in reproductive physiology to light, which may act as basis for future studies on GBPs.

Milk proteins interact with goat Binder of SPerm (BSP) proteins and decrease their binding to sperm

Seminal plasma Binder of SPerm (BSP) proteins bind to sperm at ejaculation and promote capacitation. When in excess, however, BSP proteins damage the sperm membrane. It has been suggested that milk components of semen extenders associate with BSP proteins, potentially protecting sperm. Thus, this study was conducted to investigate if milk proteins interact with BSP proteins and reduce BSP binding to goat sperm. Using gel filtration chromatography, milk was incubated with goat seminal plasma proteins and loaded onto columns with and without calcium. Milk was also fractionated into parts containing mostly whey proteins or mostly caseins, incubated with seminal plasma proteins and subjected to gel filtration. Eluted fractions were evaluated by immunoblot using anti-goat BSP antibodies, confirming milk protein-BSP protein interactions. As determined by ELISA, milk proteins coated on polystyrene wells bound to increasing of goat BSP proteins. Far-western dot blots confirmed that BSP proteins bound to caseins and β-lactoglobulin in a concentration-dependent manner. Then, cauda epididymal sperm from five goats was incubated with seminal plasma; seminal plasma followed by milk; and milk followed by seminal plasma. Sperm membrane proteins were extracted and evaluated by immunoblotting. The pattern of BSP binding to sperm membrane proteins was reduced by 59.3 % when epididymal sperm were incubated with seminal plasma and then with skimmed milk (p < 0.05). When epididymal sperm were treated with milk followed by seminal plasma, coating of sperm with BSP proteins was not significantly reduced (57.6 %; p > 0.05). In conclusion, goat BSP proteins have an affinity for caseins and whey proteins. Milk reduces BSP binding to goat sperm, depending whether or not sperm had been previously exposed to seminal plasma. Such events may explain the protective effect of milk during goat sperm preservation.

Further evidences for the mode of action of the larvicidal m-pentadecadienyl-phenol isolated from Myracrodruon urundeuva seeds against Aedes aegypti

Nowadays, dengue fever is considered the most important arbovirosis worldwide and its control is still based upon combating the vector Aedes aegypti. Besides monitoring of mosquito populations resistant to conventional insecticides, the search for new environmentally safe insecticides and conduction of molecular studies focusing on the elucidation of mode of action and possible resistance mechanisms are considered the key for a sustainable management of the mosquito vector. Thus, the present work aimed to assess changes in protein expression of 3rd-instar larvae of Ae. aegypti after exposure to the natural insecticide m-pentadecadienyl-phenol. Bidimensional electrophoresis followed by mass spectrometry resulted in identification of 12 proteins differentially expressed between control and treated groups. Larvae exposed to the toxic compound for 24h showed elevated detoxification response (glutathione-S-transferase), increased levels of stress-related proteins (HSP70) as well as evidence of lysosome stabilization to enable survival. Furthermore, expression of proteins involved in protection of peritrophic membrane and metabolism of lipids indicated systemic effect of toxic effects in treated larvae.

Purification of binder of sperm protein 1 (BSP1) and its effects on bovine in vitro embryo development after fertilization with ejaculated and epididymal sperm

The present study evaluated functional aspects of binder of sperm 1 (BSP1) in the bovine species. In a first experiment, cumulus-oocyte complexes (n = 1274) were incubated with frozen-thawed ejaculated sperm (18 hours) in Fert-TALP medium containing: heparin, 10, 20, or 40 μg/mL BSP1. Heparin followed by gelatin affinity chromatography was used for purification of BSP1 from bovine seminal vesicle fluid. With ejaculated sperm, cleavage rates were similar when Fert-TALP medium was incubated with heparin (74.1 ± 2.7%), 10 μg/mL BSP1 (77.8 ± 3.1%), or 20 μg/mL BSP1 (74 ± 2.0%). Day-7 blastocyst rates were equivalent after incubations with heparin (40.8 ± 5.0%) and 10 μg/mL BSP1 (34.1 ± 4.4%), but reduced after 20 μg/mL BSP1 (22.4 ± 2.9%) and 40 μg/mL BSP1 (19.3 ± 4.1%; P < 0.05). In the second experiment, cumulus-oocyte complexes (n = 1213) were incubated with frozen-thawed cauda epididymal sperm (18 hours) in Fert-TALP medium containing: no heparin, heparin, 10, 20, or 40 μg/mL. Cleavage and blastocyst rates were similar after treatments with heparin (68.5 ± 1.3% and 24.7 ± 3.2%, respectively) or without heparin (65.5 ± 1.8% and 27.3 ± 1.6%, respectively). Cleavage was higher after treatment with any BSP1 concentrations (74.2 ± 2.7%-79.0 ± 1.1%) than without heparin (P < 0.05). Also, cleavage was better after Fert-TALP medium incubation with 40 μg/mL BSP1 (79.0 ± 1.1%) than with heparin (68.5 ± 1.3%; P < 0.05). Embryo development was higher (P < 0.05) after treatment with 20 μg/mL BSP1 (35.6 ± 2.5%) and 40 μg/mL (41.1 ± 2%) than after incubations with heparin (24.7 ± 3.2%) or without heparin (27.3 ± 1.6%). Interestingly, BSP1 did not cause reductions in blastocyst rates after fertilization with epididymal sperm, as observed with ejaculated sperm. On the basis of immunocytochemistry, there was BSP1 binding to frozen-thawed ejaculated but not to epididymal sperm. Also, anti-BSP1 reaction remained on ejaculated sperm (as expected) and appeared on epididymal sperm after incubation with purified BSP1. Acrosome reaction of ejaculated and epididymal sperm was induced after incubation with purified BSP1 as well, indicating an effect of BSP1 on capacitation. In conclusion, purified BSP1 from bull seminal vesicles was able to bind to and induce capacitation of ejaculated and epididymal sperm. Also, BSP1 added to fertilization media and allowed proper cleavage and embryo development, with the effects being modulated by previous exposure or not of spermatozoa to seminal plasma.