The effect of cryopreservation on the turkey (Meleagris gallopavo) semen proteome

Two-dimensional difference in-gel electrophoresis coupled with matrix-assisted laser desorption/ionization mass spectrometry was employed to investigate the proteome alterations induced by equilibration and freezing/thawing processes, both in turkey spermatozoa and in extracellular fluid (ECF). The freezing/thawing process resulted in reduced semen quality parameters. Viability and motility decreased threefold (90.6 %-31.2 % and 76.0 %-26.7 %, respectively), while the proportion of live spermatozoa with intact mitochondrial membrane potential decreased fivefold (54.9 %-11.4 %). Additionally, oxidative stress increased sevenfold (10.5 %-68.8 %). A total of 146 differentially abundant protein spots were found between fresh and frozen/thawed spermatozoa, while 27 spots differentiated between fresh and frozen/thawed ECF. Immunofluorescence staining showed reduced signals of mitochondrial proteins, such as aconitate hydratase, alpha-enolase, glycerol-3-phosphate dehydrogenase, and triosephosphate isomerase, in the spermatozoa midpiece, as well as reduced signals of acrosin in the acrosome. Freezing/thawing affected mitochondrial energy metabolism, particularly the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. The maintenance of an acetyl-CoA pool to sustain TCA cycle activity in cryopreserved spermatozoa may be insufficient owing to disturbances in fatty acid beta-oxidation and/or aerobic glycolysis. Changes in the ECF primarily reflect the leakage of spermatozoa glycolytic enzymes. The freezing/thawing process alters motile cilium assembly, primarily affecting the spermatozoa axoneme and outer dense fibres. The initial step of fertilization may be disrupted by alterations in proteins involved in spermatozoa binding to the ovum. These findings extend our knowledge of the molecular and cellular mechanisms of cryodamage in turkey semen which is prerequisite for the improvement of semen preservation procedures.

Decoding the duration of fertility of laying chicken through phenotypic and proteomic evaluation

1. This study determined the effective indicators and proteins involved in long-duration fertility (DF) in chickens.2. Three lines of Chinese Xinhua chickens (900) were compared using seven phenotypic trait indicators, and the best was determined based on repeatability value. Subsequently, differential expression analysis, functional annotation and protein-protein interaction (PPI) network analyses were performed to investigate the pathways and hub proteins. Finally, qPCR analysis was conducted to validate the expression of identified hub proteins, and functional annotation with previously published genes was performed to explain how hub proteins work to maintain the trait.3. The study found that the number of fertilised eggs (FN) and maximum fertilised eggs (MCF) were the most repeatable among the seven indicators. It identified 231 differentially expressed proteins, with 144 being down-regulated and 87 being up-regulated. The differentially expressed proteins exhibited high clustering within various cellular compartments, including the cytosol and cytoplasm and GTP binding. Multiple pathways were identified, including tight and adherens junctions, TGF-beta signalling, autophagy-animal, regulation of actin cytoskeleton and the ribosome that may regulate the trait. Three hub proteins, KRAS, RPL5 (p < 0.001), and HSPA4 (p < 0.01), were significantly differentially expressed between high and low DF groups.4. This study identified FN and MCF as effective indicators for addressing DF. As it is a quantitative trait, KRAS, HSPA4, and RPL5 are potential hub proteins that work with other genes to maintain the trait.

Susceptibility of Human Spermatozoa to Titanium Dioxide Nanoparticles: Evaluation of DNA Damage and Biomarkers

Nowadays, developing countries have seen a reduction in male reproductive parameters, and it has been linked to the exposure of endocrine disrupting chemicals (EDCs), which are able to mimic or disrupt steroid hormone actions. Also, nanoparticles have shown effects on the male reproductive system, in particular the use of TiO2-NPs in drugs, cosmetics, and food as pigment additives, and, thanks to their small size (1-100 nm), provide themselves the opportunity to be internalized by the body and pass the blood-testis barrier (BTB). Therefore, TiO2-NPs can act on spermatogenesis and spermatozoa. In this study, we carried out an in vitro assay on human spermatozoa to evaluate the effects of TiO2-NPs at the concentrations of 500, 250, 100, and 50 ppm. Exposure did not statistically alter sperm parameters (e.g., motility and viability) but induced damage to sperm DNA and the expression of biomarkers by spermatozoa. This immunofluorescence investigation showed a positivity for biomarkers of stress (HSP70 and MTs) on the connecting piece of spermatozoa and also for sex hormone binding globulin (SHBG) biomarkers. The SHBG protein acts as a carrier of androgens and estrogens, regulating their bioavailability; therefore, its expression in the in vitro assay did not rule out the ability of TiO2-NPs to act as endocrine disruptors.

Mechanisms underlying reproductive responses of Japanese quails to heat stress conditions

Exposure to heat stress can cause a significant increase in the death rate and disease susceptibility of poultry birds, ultimately impacting the profitability of the poultry industry. Despite being a more economical choice, Japanese quails (Coturnix japonica) are not immune to the harmful effects of heat stress. Quails may experience negative effects on their reproductive performance due to excessive reactive molecules caused by heat stress. However, they have developed various mechanisms to maintain their reproductive abilities in such conditions. The neuroendocrine system in birds plays a vital role in regulating their reproductive responses to thermal stress, and it is also connected to other environmental factors such as photoperiod that can impact their reproductive performance. Hormones are crucial in the complex interactions necessary for sexual maturation and reproductive responses to heat stress in Japanese quails living in stressful thermal conditions.

Key miRNAs of chicken seminal plasma extracellular vesicles related with sperm motility regulation

MicroRNAs (miRNAs) are bio-active elements cargoed by seminal plasma extracellular vesicles extracellular vesicles (SPEVs) which are crucial for sperm function and fertility modulation. This study aimed to isolate, characterize, and identify the miRNA expression profiles in the SPEVs from high (HSM) and low sperm motility (LSM) groups that could serve as fertility biomarkers and explain the underlying mechanisms. The isolated SPEVs were round spherical structures of approximately 50-200 nm in diameter expressing molecular markers. A total of 1006 and 1084 miRNAs were detected in HSM and LSM, respectively, with 34 being differentially expressed. Their targeted genes involved in SNARE interactions in vesicular transport, Metabolic pathways, and Apelin signaling pathway, etc. The joint analysis with mRNAs of sperm and sperm storage tubules cells highlighted the cellular communication mediated by SPEVs miRNAs, where they may rule fertility by affecting sperm maturation and amino acid metabolism. SPEVs as additives could improve fertility of fresh and frozen sperm, while the knockdown of one of the differentially expressed miRNAs, miR-24-3p, diminished this effect, indicating its crucial roles. This study expands our understanding of SPEVs miRNAs mediated sperm maturation and fertility modulation, and may help to develop new therapeutic strategies for infertility and sperm storage.

Sperm storage by females across the animal phyla: A survey on the occurrence and biomolecules involved in sperm storage

Long-term sperm storage by females in various regions of the oviduct is documented across many invertebrate and vertebrate species. Although, many reports emphasize on the histology, histochemistry and ultrastructural features of sperm storage, very little is known about the mechanisms underlying the sperm storage. The current review documents the occurrence of sperm storage by females in a wide array of invertebrate and vertebrate species. This review also provides an insight on the presence of various molecular factors of the sperm storage tubules presumably responsible for the prolonged sperm storage with an emphasis on a model reptile, the Indian garden lizard, Calotes versicolor which contains a unique approximately 55-kDa protein in its utero-vaginal lavage and found to inhibit washed epididymal sperm motility in a concentration and time-dependent manner in a reversible fashion.

Sperm Motility Regulation in Male and Female Bird Genital Tracts

Sperm drastically change their flagellar movement in response to the surrounding physical and chemical environment. Testicular sperm are immotile; however, they gain the competence to initiate motility during passage through the male reproductive tract. Once ejaculated, the sperm are activated and promptly initiate motility. Unlike mammals, ejaculated sperm in birds are stored in specialized tubular invaginations referred to as sperm storage tubules (SSTs), located between the vagina and uterus, before fertilization. The resident sperm in the SSTs are in a quiescent state and then re-activated after release from the SSTs. It is thought that avian sperm can undergo motility change from quiescent to active state twice; however, the molecular mechanism underlying sperm motility regulation is poorly understood. In this short review, we summarize the current understanding of sperm motility regulation in male and female bird reproductive tracts. We also describe signal transduction, which regulates sperm motility, mainly derived from in vitro studies.

Effects of coenzyme Q10 on reproductive performance of laying Japanese quail (Coturnix japonica) under cadmium challenge

Japanese quail is an increasingly important bird of economic importance for commercial egg and meat production, particularly in developing countries. There is a need for research aimed at improving efficiency of these birds during stressful challenges, such as oxidative stress. Coenzyme Q10 (CoQ10), a highly functional antioxidant, protects cells against oxidative stress. This study was conducted to determine the effects of CoQ10 on reproductive performance of Japanese quail under cadmium (Cd) challenge. A total of 216 six-wk-old Japanese quail were randomly allocated into 3 groups for an 8 wk experimental trial. The treatments include a negative control (NC): feeding basal diet; a positive control (PC): feeding basal diet and cadmium administration (1 mg/100 g BW, at 10 and 11 wk of age), and (CdQ10): feeding CoQ10 supplemented (900 mg/kg diet) basal diet and Cd administration. At 11 and 13 wk of age, egg production, body weight, mortality, oviduct, and ovarian biometry, were recorded. Histology and histopathology of isthmus and magnum, fertility, hatchability, hatchling quality, and HSP70 mRNA transcript abundance in the utero-vaginal junction (UVJ) were evaluated. Positive control and CdQ10 group had no significant effect on live body weight, stroma weight, follicle size, hatchability, and fertility; however, Cd administration increased (P < 0.01) mortality rate in the PC group compared to the NC and CdQ10 groups. CdQ10 quail produced more eggs and had a higher hatchling quality compared to the PC group (P < 0.01). The thickness and height of isthmus and magnum folds in the CdQ10 group was increased compared to the PC group (P < 0.01) and overall oviduct weight was increased with CoQ10 supplementation (P < 0.01). Compared to PC, the CdQ10 group had a reduction in infiltration of inflammatory cells. Relative abundance of HSP70 mRNA in UVJ was influenced by interactive effect of treatment × time (P < 0.05). In conclusion, dietary supplementation of CoQ10 showed beneficial effects on some reproduction characteristics of female Japanese quail under Cd-induced oxidative stress.

HSP70-16 and VDAC3 jointly inhibit seed germination under cold stress in Arabidopsis

Abscisic acid (ABA) transport plays a crucial role in seed germination under unfavourable conditions such as cold stress. Both heat shock protein 70 (HSP70) and voltage-dependent anion channel (VDAC) protein are involved in cold stress responses in Arabidopsis. However, their roles in seed germination with regard to ABA signaling remain unknown. Here we demonstrated that Arabidopsis HSP70-16 and VDAC3 jointly suppress seed germination under cold stress conditions. At 4°C, both HSP70-16 and VDAC3 facilitated the efflux of ABA from the endosperm to the embryo and thus inhibited seed germination. HSP70-16 interacted with VDAC3 on the plasma membrane and in the nucleus, and the interplay between HSP70-16 and VDAC3 activated the opening of the VDAC3 ion channel. Our work established a novel function of HSP70-16 in seed germination under cold stress and a possible association of VDAC3 activity with ABA transportation from endosperm to embryo under cold stress conditions. This study reveals that HSP70-16 interacts with VDAC3 and facilitates the opening of the VDAC3 ion channel, which influences ABA efflux from endosperm to embryo, thus negatively regulates seed germination under cold stress.

Female sperm storage in the bonnethead Sphyrna tiburo oviducal gland: Immunolocalization of steroid hormone receptors in sperm storage tubules

Female sperm storage (FSS) has been demonstrated to occur in representatives from all major vertebrate groups and has been hypothesized to have several possible adaptive benefits that may maximize reproductive success of its practitioners. However, while the range of taxa that exhibit FSS and its possible evolutionary benefits have received significant attention in past years, the physiological mechanisms by which FSS occurs in vertebrates have only recently been explored. In this study, we examined the potential role of gonadal steroid hormones in regulating FSS in the bonnethead Sphyrna tiburo, a small hammerhead species in which females have been shown to be capable of storing male spermatozoa for up to 6 - 7 months following copulation. Like past studies on this species, we observed associations between plasma concentrations of the gonadal steroids 17β-estradiol, testosterone, and progesterone with FSS in female bonnetheads, suggesting roles for these hormones in regulating this process. Using immunohistochemistry, we also observed presence of androgen receptor, estrogen receptor alpha (ERα), and progesterone receptor in epithelial cells of sperm storage tubules in the bonnethead oviducal gland, as well as occurrence of ERα in stored spermatozoa, specifically during the sperm storage period. These results suggest that E₂, T, and P₄ may regulate certain aspects of FSS in bonnethead indirectly through actions on the female reproductive tract, whereas E₂ may also have direct effects on sperm function. This is the first study on the regulation of FSS in sharks and has formed a basis for future work geared towards improving our understanding of this process in chondrichthyans.

Physiological factors influencing female fertility in birds

Fertility is fundamental to reproductive success, but not all copulation attempts result in a fertilized embryo. Fertilization failure is especially costly for females, but we still lack a clear understanding of the causes of variation in female fertility across taxa. Birds make a useful model system for fertility research, partly because their large eggs are easily studied outside of the female's body, but also because of the wealth of data available on the reproductive productivity of commercial birds. Here, we review the factors contributing to female infertility in birds, providing evidence that female fertility traits are understudied relative to male fertility traits, and that avian fertility research has been dominated by studies focused on Galliformes and captive (relative to wild) populations. We then discuss the key stages of the female reproductive cycle where fertility may be compromised, and make recommendations for future research. We particularly emphasize that studies must differentiate between infertility and embryo mortality as causes of hatching failure, and that non-breeding individuals should be monitored more routinely where possible. This review lays the groundwork for developing a clearer understanding of the causes of female infertility, with important consequences for multiple fields including reproductive science, conservation and commercial breeding.

High-throughput sequencing reveals differential expression of miRNAs in yak and cattleyak epididymis

Cattleyaks (CY) are interspecific hybrids between cattle (Bos taurus) and yak (Bos gruniens, YK) exhibiting the same prominent adaptability and higher performances than YK. MiRNAs have played an important role in the acquisition and maintenance of male fertility in reproduction, where deletion of Dicer in mice germ cells results in infertility. According to a body of evidence, the function of miRNA in the male reproductive system extends from the testis into the epididymis and, as such, regulates gene expression and contributes to regional gene expression variations. Using RNA sequencing on biological replicates, we described differentially expressed miRNAs profiles for tissue from epididymis of YK and CY. In the present study, High-throughput sequencing analysis showed that 55 differentially expressed (DE) miRNAs were identified in the epididymis of YK and CY. Among these, 43 DE miRNAs were upregulated while the remaining 12 DE miRNAs were downregulated between epididymis of YK and CY. Our results showed that the top most important DE miRNAs, bta-miR-449c, bta-miR-539, bta-miR-136, bta-miR-504, bta-miR-31 and bta-miR-222 were found to be involved in the reproductive system of CY. In addition, some targeted genes, Clusterins (CLU), Retinoic Acid Receptor a (RARa) and Hydroxy acyl glutathione Hydrolase (HAGH) and HSPH1 targeted by bta-miR-2411-3p and bta-miR-1298 were involved in the sperm motility, sperm morphology and post-testicular sperm maturation. Furthermore, GO and KEGG analyses were performed to classify the functions of target genes for DE miRNAs. In addition, RT-qPCR validation of the DE miRNAs and its targeted genes revealed that putative miRNAs are involved in the male CY infertility by altering the gene expression. Present findings may not only increase our understanding of the molecular mechanisms regulated by the miRNAs in epididymis, but also provide a valuable information to understand the male infertility mechanism of CY.

Association of heat shock protein A2 expression and sperm quality after N-acetyl-cysteine supplementation in astheno-terato-zoospermic infertile men

In infertile men, reduced expression of heat shock protein A2 (HSPA2) is related to reduced sperm quality and function. The present study has aimed to investigate the effects of N-acetyl-cysteine (NAC) supplementation on expression of heat shock protein A2 (HSPA2). In this study in continuation of previous study, semen samples from 50 astheno-terato-zoospermic men who have received NAC (600 mg/day) orally for three months were evaluated for expression HSPA2 using RT-PCR, and Western blot analysis. In addition, semen samples of these individuals were assessed for sperm parameters, DNA fragmentation (TUNEL), protamine deficiency (CMA3), lipid peroxidation index (MDA) and total antioxidant capacity (TCA). All assessment was carried out before and after NAC treatment. In addition to improved sperm parameters and aforementioned functional parameters, the presented results revealed the significant increase in relative expression levels of HSPA2 was obtained after using NAC treatment (p < .05). Correlation analysis also demonstrated that HSPA2 expression is significantly related to most of the assessed parameters. NAC may directly or indecently impose its beneficial effect through increased expression of HSPA2, which plays a potential role in proper folding of element needed to counteract stress condition in infertile individuals.

Transcriptomic and metabolomic insights into the variety of sperm storage in oviduct of egg layers

In birds, the sperm storage tubules (SST) are dispersed in uterovaginal junction (UVJ) and highly correlated with differential capacity of sperm storage (SS) in and among species with unspecified mechanisms. Here, the SS duration of 252 egg layer breeders was evaluated in 5 rounds with 3 phenotypic traits to screen high- and low-SS individuals, respectively, followed with transcriptome of UVJ tissues and metabolome of serum (high-SS vs. low-SS) to decipher the candidate genes and biochemical markers correlated with differential SS capacity. Histological characterization suggested slightly higher density of SST in UVJ (high-SS vs. low-SS). Transcriptome analyses identified 596 differentially expressed genes (336 upregulated vs. 260 downregulated), which were mainly enriched in gene ontology terms of homeostasis, steroid and lipid metabolism and hormone activity, and 12 significant pathways (P < 0.05) represented by calcium, steroid, and lipid metabolism. Immunohistochemical staining of GNAQ, ST6GAL1, ADFP, and PCNA showed similar distribution in UVJ tissues between 2 groups. Several candidates (HSD11B2, DIO2, AQP3, GNAQ, NANS, ST6GAL1) combined with 4 (11β-prostaglandin F2α, prostaglandin B1, 7α-hydroxytestosterone, and N-acetylneuraminic acid) of 40 differential metabolites enriched in serum metabolome were considered as regulators and biomarkers of SS duration in egg layer breeders. The integrated transcriptome and metabolome analyses of chicken breeder hens will provide novel insights for exploration and improvement of differential SS capacity in birds.

Distinct expression and localization patterns of HSP70 in developmental reproductive organs of rams

Heat shock protein 70 (HSP70) has been widely reported to play a vital role in maintaining intracellular homeostasis, mainly through cellular protection and immune regulation. The expression and function of HSP70 can vary depending upon species and age. To explore the expression signatures and regulatory functions of HSP70 in the reproductive organs of male sheep, we evaluated the expression and distribution patterns of HSP70 in the testes and epididymides (caput, corpus, and cauda) of Tibetan sheep at three developmental stages (i.e., 3 months, 1 year and 3 years after birth) by qRT-PCR, Western blot and immunofluorescence. HSP70 was found to be expressed in testes, caput, corpus, and cauda epididymides throughout the developmental stages but is mainly expressed postpuberty (1 year and 3 years old). Immunofluorescence results revealed that in the testes, a positive reaction for HSP70 protein was mainly seen in round spermatids and luminal sperms from the groups aged 1 year and 3 years. In caput epididymides, the positive signals for HSP70 protein was notably observed in sperm and principal cells of the epididymal epithelium from the groups aged 1 year and 3 years, and positive signals in the epididymal interstitium were found in all three age groups. In corpus and cauda epididymides, HSP70 protein was present in the epididymal epithelium and interstitium, and the positive signals gradually increased with age. In conclusion, these findings suggest that Tibetan sheep HSP70 may play a crucial role in further development and maturation of postmeiotic germ cells and participate in regulation of intraepididymal homeostasis maintenance in Tibetan sheep.

Proteome-wide identification of HSP70/HSC70 chaperone clients in human cells

The 70 kDa heat shock protein (HSP70) family of chaperones are the front line of protection from stress-induced misfolding and aggregation of polypeptides in most organisms and are responsible for promoting the stability, folding, and degradation of clients to maintain cellular protein homeostasis. Here, we demonstrate quantitative identification of HSP70 and 71 kDa heat shock cognate (HSC70) clients using a ubiquitin-mediated proximity tagging strategy and show that, despite their high degree of similarity, these enzymes have largely nonoverlapping specificities. Both proteins show a preference for association with newly synthesized polypeptides, but each responds differently to changes in the stoichiometry of proteins in obligate multi-subunit complexes. In addition, expression of an amyotrophic lateral sclerosis (ALS)-associated superoxide dismutase 1 (SOD1) mutant protein induces changes in HSP70 and HSC70 client association and aggregation toward polypeptides with predicted disorder, indicating that there are global effects from a single misfolded protein that extend to many clients within chaperone networks. Together these findings show that the ubiquitin-activated interaction trap (UBAIT) fusion system can efficiently isolate the complex interactome of HSP chaperone family proteins under normal and stress conditions.

Development of a ubiquitin-based system to comprehensively identify substrates of HSP70 enzymes in human cells reveals that constitutive HSC70 and stress-induced HSP70 have different binding preferences and respond dynamically to changes in misfolded protein levels.

Effects in broiler hens of genetic lines differing in fertility, biotin supplementation, and age on relative abundance of oviductal transforming growth factor-β and carbonic anhydrase mRNA transcripts

There was evaluation of effects of biotin administration on oviductal abundance of transforming growth factor-β (TGF-β) and carbonic anhydrase (CA) mRNA transcript in younger and older broiler hens of relatively lesser and greater fertility lines. Additionally, effects of biotin supplementation on attenuation of age-related subfertility were evaluated. Hens from the relatively greater (Line D, n = 60) and lesser (Line B, n = 60) fertility rate line were randomly assigned to three treatment groups. Biotin was not or was administered in drinking water from 30 to 33 (younger age) and 53 to 56 (older age) wk of age to have access to no biotin (T₀), or 0.3 (T₁), or 0.45 (T₂) mg/L of biotin. There was assessment the relative oviductal abundances of TGF-β and CA mRNA transcript abundances. Supplemental biotin and age had no effect on the relative abundance of oviductal TGF-β mRNA transcript in hens of Line D. There, however, was a ten-fold greater abundance of TGF-β in hens of the T₀ group of Line B compared with Line D. Relative abundance of TGF-β mRNA transcript was greater in younger hens of Line B; however, biotin supplementation of older hens of the T₂ group of Line B resulted in a similar TGF-β abundance to that of younger hens. Inconstant with the TGF-β abundance, CA abundance in hens of Line B was not affected by supplemental biotin or bird age. Overall, differences in TGF-β or CA abundances did not affect fertility of broiler hens.

VDAC and its interacting partners in plant and animal systems: an overview

Molecular trafficking between different subcellular compartments is the key for normal cellular functioning. Voltage-dependent anion channels (VDACs) are small-sized proteins present in the outer mitochondrial membrane, which mediate molecular trafficking between mitochondria and cytoplasm. The conductivity of VDAC is dependent on the transmembrane voltage, its oligomeric state and membrane lipids. VDAC acts as a convergence point to a diverse variety of mitochondrial functions as well as cell survival. This functional diversity is attained due to their interaction with a plethora of proteins inside the cell. Although, there are hints toward functional conservation/divergence between animals and plants; knowledge about the functional role of the VDACs in plants is still limited. We present here a comparative overview to provide an integrative picture of the interactions of VDAC with different proteins in both animals and plants. Also discussed are their physiological functions from the perspective of cellular movements, signal transduction, cellular fate, disease and development. This in-depth knowledge of the biological importance of VDAC and its interacting partner(s) will assist us to explore their function in the applied context in both plant and animal.

Avian uterine fluid proteome: Exosomes and biological processes potentially involved in sperm survival

Uterine fluid is an aqueous milieu to which sperm are exposed during their storage and ascent. In this study, a bottom-up proteomic strategy and bioinformatic analysis of hen uterine fluid was performed to improve the understanding of this fluid and its potential role in sperm survival mechanisms. The proteomic data were submitted to ProteomeXchange. Among the 913 proteins identified, 160 are known to be secreted and 640 are referenced in exosomes databases. We isolated exosomes from the avian uterine fluid, analyzed them using electron microscopy, and targeted several exosomes markers (ANXA1/2/4/5, VCP, HSP90A, HSPA8, PARK7, and MDH1) using immunoblotting. Electron microscopy and immunohistochemistry were also used to analyze uterovaginal junctions for the exosomal proteins ANXA4, VCP, and PARK7. Exosomes were observed both at the surface epithelium and inside sperm storage tubules. Our data were compared with two previously published studies on proteomic of hen uterine fluid, and with one study describing the proteomic content of rooster seminal plasma and sperm. In conclusion, we demonstrated for the first time that avian uterine fluid contains exosomes. These may play a key role in preserving sperm functions within the female genital tract. Their presence in the sperm storage tubules may represent an important mechanism regarding interaction between the female genital tract and sperm.

Infundibular sperm storage and uterine muscular twisting in the Amazonian lancehead, Bothrops atrox

Although knowledge about the reproduction of snakes of the genus Bothrops has increased recently, many questions remain regarding sperm storage by these neotropical pitvipers. The relationship between two known sperm storage sites-the nonglandular uterus and the infundibulum-has yet to be detailed for Bothrops. In addition, the formation of uterine muscular twisting (UMT) and its function in sperm storage in the nonglandular uterus have been questioned. This article presents data on both sperm storage sites (posterior infundibulum and nonglandular uterus) in the Amazonian lancehead, Bothrops atrox, aiming to address the role of UMT in bothropoid reproduction considering female reproductive stages, timing of sperm storage, and morphology and histochemistry of sperm receptacles. The oviduct of B. atrox is composed of the infundibulum (anterior and posterior), the glandular uterus, the nonglandular uterus and the pouch. Sperm storage occurs in the posterior infundibulum and nonglandular uterus in vitellogenic females. In the posterior infundibulum sperm is stored in receptacles, while in the nonglandular uterus it is stored in crypts in the UMT of vitellogenic females. Both sperm storage sites possess granules testing positive for neutral mucopolysaccharides in the presence of spermatozoa, possibly favoring the conditions for spermatozoa surveillance during sperm storage in the reproductive tract.

Sperm Gatekeeping: 3D Imaging Reveals a Constricted Entrance to Zebra Finch Sperm Storage Tubules

Females across many internally fertilizing taxa store sperm, often in specialized storage organs in their reproductive tracts. In birds, several hundred sperm storage tubules exist in the utero-vaginal junction of the oviduct, and there is growing evidence that sperm storage in these tubules is selective. The mechanisms underlying female sperm storage in birds remain unknown because of our limited ability to make three-dimensional, live observations inside the large, muscular avian oviduct. Here, we describe a new application of fluorescence selective plane illumination microscopy to optically section oviduct tissue from zebra finch Taeniopygia guttata females label free by harnessing tissue autofluorescence. Our data provide the first description of the three-dimensional structure of sperm storage organs in any vertebrate to the best of our knowledge and reveal the presence of gate-like constricted openings that may play a role in sperm selection.

Comparative proteomic analysis of sex-biased proteins in ovary and testis at different stages of Spodoptera litura

Sex-biased protein is thought to be able to drive the phenotypic differences in males and females in insects. In this study, 1385 and 1727 proteins were identified as differentially accumulated proteins (DAPs) by comparing the protein abundances at pupae stage with those at adult stage in ovary and testis of S.litura, respectively. And among which, 548 DAPs were showed to be expressed in both ovary and testis, and 837 and 1179 proteins were considered as ovary-specific and testis-specific DAPs, respectively. To further identify DAPs related to gonad development and sex dimorphism, a total of 320 DAPs were selected and defined as "proteins of specific interest" based on several selecting criteria. Sex dimorphism is a complex and dynamic developmental progress, and these identified DAPs were suggested to be involved in multiple functions such as organonitrogen compound catabolic process, glycosylation, proteasome, N-Glycan biosynthesis and other reproduction-related processes. Overall, our results highlighted these sexual-biased, gonad development related and sexual dimorphism related DAPs, and their abundance variations along with development were also examined, which could provide important information for their functional analysis in reproduction and potential biomarkers for developing useful strategies against S. litura and other orthologous pests. BIOLOGICAL SIGNIFICANCE: Sex dimorphism entails the differentiation of two sexual functions, resulting in sexually phenotypic differences and leading to the development of female and male morphologies and behaviors. However, sex dimorphism related proteins remain to be identified in many non-model insects. In this study, iTRAQ-based proteomic analysis was applied to examine the variations of protein abundances at pupae stage and adult stage in ovary and testis of S.litura, respectively. Reproduction and sex dimorphism related proteins were further identified as "proteins of specific interest". These identified candidate proteins provided valuable information for their further functional analysis in reproduction and could serve as potential biomarkers for developing useful strategies against S. litura and other orthologous pests.

Role of genome-wide mRNA-seq profiling in understanding the long-term sperm maintenance in the storage tubules of laying hens

Sperm storage function of the sperm storage tubules (SSTs) is directly correlated with the fertility of laying hens. SSTs are located at the utero-vaginal junction (UVJ) and infundibulum of the hen oviduct. However, little is known about the cellular and molecular mechanisms responsible for long-term sperm maintenance in the lumen of the SSTs. In this study, we profiled transcriptomes to detect the different gene expressions between infundibulum and UVJ using RNA-seq. As a result, we identified a total of 1382 differentially expressed genes (DEGs). GO analysis showed that fat acid metabolism, regulation of cell differentiation, regulation of transport, and immune response were enriched for these DEGs, and many of the pH-regulatory functions genes such as CAIV and SLC4A4 were highly expressed in UVJ, which inferred that SSTs could preserve sperm by regulating physiological functions in UVJ. Our results provide new insight to understand the specific function for SSTs to extend sperm life span in the oviduct of laying hens.

Identification and characterization of the zebra finch (Taeniopygia guttata) sperm proteome

Spermatozoa exhibit remarkable variability in size, shape, and performance. Our understanding of the molecular basis of this variation, however, is limited, especially in avian taxa. The zebra finch (Taeniopygia guttata) is a model organism in the study of avian sperm biology and sperm competition. Using LC-MS based proteomics, we identify and describe 494 proteins of the zebra finch sperm proteome (ZfSP). Gene ontology and associated bioinformatics analyses revealed a rich repertoire of proteins essential to sperm structure and function, including proteins linked to metabolism and energetics, as well as tubulin binding and microtubule related functions. The ZfSP also contained a number of immunity and defense proteins and proteins linked to sperm motility and sperm-egg interactions. Additionally, while most proteins in the ZfSP appear to be evolutionarily constrained, a small subset of proteins are evolving rapidly. Finally, in a comparison with the sperm proteome of the domestic chicken, we found an enrichment of proteins linked to catalytic activity and cytoskeleton related processes. As the first described passerine sperm proteome, and one of only two characterized avian sperm proteomes, the ZfSP provides a significant step towards a platform for studies of the molecular basis of sperm function and evolution in birds. SIGNIFICANCE: Using highly purified spermatozoa and LC-MS proteomics, we characterise the sperm proteome of the Zebra finch; the main model species for the avian order Passeriformes, the largest and most diverse of the avian clades. As the first described passerine sperm proteome, and one of only two reported avian sperm proteomes, these results will facilitate studies of sperm biology and mechanisms of fertilisation in passerines, as well as comparative studies of sperm evolution and reproduction across birds and other vertebrates.

A new DNA marker of the TMIGD1 gene used to identify high fertilization rates in Tsaiya ducks (Anas platyrhynchos)

In a prior study, comparisons of individuals of Anas platyrhynchos with higher/lower reproductive performances showed that the expression of the transmembrane and immunoglobulin domain containing 1 (TMIGD1) gene significantly differed between the two groups. Here, we demonstrate that ducks with the TMIGD1 GG genotype have a significantly higher fertilization rate than other TMIGD1 genotypes. Primers designed based on the TMIGD1 sequence of Pekin duck were able to successfully amplify a TMIGD1 fragment from Tsaiya ducks, and sequencing results indicated that a single nucleotide polymorphism (SNP) of the TMIGD1 gene existed. We also developed a cost-effective method of restriction fragment length polymorphism. Using the above methods, ducks were classified into three genotypes. To identify the relationships between genotypes and traits, we recorded the ducks’ performance; to ensure the coverage of the entire duration of the fertile period, the egg collection period was extended to 18 days, and therefore, lower than usual fertilization rates were observed. Further assessment using a high-throughput system showed that the ducks with the GG genotype exhibited the highest fertilization rates among genotypes (P < 0.05). We suggest that TMIGD1 may affect the release of sperm protection factors from the female genital tract, and thus alter fertilization rate. In conclusion, the results of this study demonstrate that the TMIGD1 GG genotype can be used as a new DNA marker to identify animals with high fertilization rates at a young age, a process which could improve farming efficiency.

Idiopathic male infertility in the Han population in China is affected by polymorphism in the VDAC2 gene

BACKGROUND

It has been proved that human voltage-dependent anion channel 2 (VDAC2) plays a significant role in sperm function and male fertility. This study was primarily aimed at exploring whether VDAC2 is a risk factor for idiopathic male infertility.

RESULTS

We determined a significantly increased risk of idiopathic infertility with abnormal semen parameters in association with the variant rs2804535 and a decreased risk of idiopathic infertility with abnormal semen parameters in association with the variant rs11001334. However, among subjects with normal semen parameters, no significant differences could be found in these genotypes. Moreover, we could not find any differences in the variants rs7896741 and rs1259503, which showed no risk of male infertility, whether normal or abnormal.

MATERIALS AND METHODS

All of the experimental subjects, including 523 men who cannot conceive children and 277 fertile controls, underwent complete historical and physical examinations. Each participant donated an ejaculate for semen analysis and 5 ml of peripheral blood for genomic DNA extraction. A computer-assisted semen analysis system was used for the semen analysis. Four single-nucleotide polymorphisms were identified and analyzed using TaqMan SNP Genotyping Assays.

CONCLUSIONS

The result shows that the relationships between different variants in the VDAC2 gene and male fertility differ, and the individuals who carry those variants may have a decreased or increased risk of abnormal semen parameters associated with male infertility.

Proteinaceous sperm motility inhibitory factor from the female Indian garden lizard Calotes versicolor

Female sperm storage is an intriguing adaptation exhibited by a wide array of both vertebrates and invertebrates. The mechanisms underlying female sperm storage have remained elusive. Using the Indian garden lizard Calotes versicolor as a model organism, we investigated the role of low and high molecular weight factors in this phenomenon. Previously, we demonstrated three distinct phases of the reproductive cycle in this animal with live, motile spermatozoa recovered from the uterovaginal region during the reproductive phase. In the present study, we analysed the uterovaginal contents using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified an abundant protein band corresponding to ~55 kDa regardless of the phase of the reproductive cycle. Analysis of the purified protein by liquid chromatography-tandem mass spectrometry suggested a unique protein without any homology to the National Center for Biotechnology Information database. Exogenous addition of this protein to washed spermatozoa derived from the epididymis reversibly inhibited sperm motility in a concentration- and time-dependent manner, suggesting it plays a key role in sperm storage. These studies are likely to offer new avenues to unravel the secrets of female sperm storage seen across the animal taxa and may have novel applications not only in reproductive biology, but also in general cell storage and preserving endangered animal species.

Effects of a Protein Kinase Inhibitor on Sperm Motility in the Japanese Quail

Sperm motility is an essential trait for successful fertilization in animals. In birds, ejaculated sperm migrate into sperm storage tubules before fertilization and are stored in a quiescent state. We previously reported that this type of sperm's flagellar quiescence was induced by lactic acid through flagellar dynein ATPase inactivation following cytoplasmic acidification (<pH 6.0). However, signal transduction in the sperm cells leading to motility inactivation is not well understood. The aim of the present study was to investigate the role of protein kinases in putative signal transduction in quail spermatozoa motility in vitro. Following incubation with bisindolylmaleimide II (BisII), a potent-competitive protein kinase C (PKC) inhibitor, sperm motility decreased in a dose related-manner. However, no such inhibitory effect was found in sperm exposed to bisindolylmaleimide V, H-89, or LY294002, a weak inhibitor of PKC, a potent inhibitor of protein kinase A (PKA) and a selective inhibitor of phosphatidylinositol 3-kinase, respectively. BisII-treated sperm exhibited no significant differences in pH _i , [Ca²⁺] _i , mitochondrial activity, intracellular cAMP or ATP concentration, as well as dynein ATPase activity, compared to the control sperm. However, when the phosphorylated substrate proteins by PKC were detected by Western blot analysis, the intensity of the band in sperm incubated in the presence of BisII decreased. Moreover, immunoreactive PKCι and µ isoforms in the sperm lysates were also detected. These results indicated that the PKC signaling pathway may be involved in sperm motility regulation, and protein phosphorylation by PKC may be required to maintain flagellar movement in the Japanese quail.

Sperm Storage in the Female Reproductive Tract

The capacity for sperm storage within the female reproductive tract occurs widely across all groups of vertebrate species and is exceptionally well developed in some reptiles (maximum duration seven years) and fishes (maximum duration >1 year). Although there are many reports on both the occurrence of female sperm storage in diverse species and its adaptive benefits, few studies have been directed toward explaining the mechanisms involved. In this article we review recent findings in birds and mammals in an effort to develop hypotheses that could be translated into research applications in animal breeding technologies. There are pockets of evidence to suggest that the local epithelial cells, sometimes arranged as sperm storage tubules, can respond to spermatozoa by producing heat shock proteins as well as providing an environment rich in antioxidants. Moreover, the local immune system seems to tolerate the arrival of spermatozoa, while retaining the ability to combat the arrival of infectious microorganisms.

A unique mechanism of successful fertilization in a domestic bird

Fertilization is an indispensable step for formation of a zygote in sexual reproduction, leading to species survival. When mating occurs, sperm is transported to the female reproductive tracts via the seminal plasma (SP). SP is derived from male accessory sex glands and it plays pivotal roles for fertilization in animals. However, molecular mechanisms of SP or a fluid derived from male accessory sex glands for successful fertilization remain unclear. Here, we report that in male quail the cloacal gland (CG) produces prostaglandin F_2α (PGF_2α) that contributes to successful fertilization. PGF_2α, as well as the secretion of CG (CGS), induced vaginal contractions and caused the opening of the entrance of the sperm storage tubules, the structures responsible for the long-term sperm storage and fertilization. The removal of CGS from the male before mating reduced the fertility, but the supplementation of CGS or PGF_2α rescued the subfertility. We further showed that male CG contains glucose that is utilized as energy source for the intrinsic sperm mobility after transportation to female vagina. This mechanism, in concert with the excitatory effects of PGF_2α enables successful fertilization in the domestic bird.

In-depth proteomic analysis of carp (Cyprinus carpio L) spermatozoa

Using a combination of protein fractionation by one-dimensional gel electrophoresis and high performance liquid chromatography-electrospray ionization tandem mass spectrometry, we identified 348 proteins in carp spermatozoa, most of which were for the first time identified in fish. Dynein, tubulin, HSP90, HSP70, HSP60, adenosylhomocysteinase, NKEF-B, brain type creatine kinase, mitochondrial ATP synthase, and valosin containing enzyme represent high abundance proteins in carp spermatozoa. These proteins are functionally related to sperm motility and energy production as well as the protection of sperm against oxidative injury and stress. Moreover, carp spermatozoa are equipped with functionally diverse proteins involved in signal transduction, transcription, translation, protein turnover and transport. About 15% of proteins from carp spermatozoa identified here were also detected in seminal plasma which may be a result of leakage from spermatozoa into seminal plasma, adsorption of seminal plasma proteins on spermatozoa surface, and expression in both spermatozoa and cells secreting seminal plasma proteins. The availability of a catalog of carp sperm proteins provides substantial advances for an understanding of sperm function and for future development of molecular diagnostic tests of carp sperm quality, the evaluation of which is currently limited to certain parameters such as sperm count, morphology and motility or viability. The mass spectrometry data are available at ProteomeXchange with the dataset identifier PXD000877 (DOI: http://dx.doi.org/10.6019/PXD000877).