Sperm Storage Research Articles

Queen quality, performance, and winter survival of imported and domestic honey bee queen stocks

Canadian beekeepers have faced high colony mortality each winter over the last decade. Frequently citing “poor queen quality” as a top contributing factor to colony loss, Canadian beekeepers report needing to replace half their queens each year. Domestic queen production exists throughout Canada but is limited due to the short season and can be further limited when colony mortality is high. Consequently, Canadian beekeepers import over 260,000 queens annually, primarily from locations with warmer climates. In this study, newly mated imported queens from Hawaii (USA) and New Zealand were compared to domestic Canadian queens produced in British Columbia; these stocks were evaluated on their morphological and sperm storage characteristics. Stock quality was also evaluated in the field at two locations in Alberta, Canada over two production seasons. Our results show initial variation in queen morphology and fertility among imported and domestic queen stocks. Most striking, the New Zealand queens weighed 10–13% less than the Hawaii and British Columbia queens, respectively upon arrival. Colony performance over a two-year field study suggests: (1) brood pattern solidness has a positive nonlinear correlation with honey production regardless of queen stock and environment; (2) environment (i.e., apiary location) and queen stock variably predict colony health and productivity depending on year; specifically, apiary site appears to be a stronger predictor of colony health and productivity than queen stock in year one, but in year two, queen stock appears to be a stronger predictor than apiary site; (3) high clinical symptoms of chalkbrood may explain the prevalence of poor brood patterns in colonies headed by queens from New Zealand; (4) domestic queens are 25% more likely to survive winter in Alberta than imported queens. Therefore, it is important to consider possible mismatches in disease immunity and climate conditioning of imported queen stocks heading colonies in temperate regions that face drastically different seasonal climates and disease ecology dynamics.

The effects of female age on blood-feeding, insemination, sperm storage, and fertility in the dengue vector mosquito Aedes aegypti (Diptera: Culicidae)

Mating induces behavioral and physiological changes in female insects—collectively referred to as the female post-mating response (PMR)—that facilitate the production of progeny. PMRs are elicited by transfer of male-derived seminal components during mating, but are altered by other factors, including adult age. Increased female age is often accompanied by declines in fertility. However, mating shortly after emergence also impacts fertility in the insect model Drosophila melanogaster. Here, we determined the age post-emergence when females of the vector mosquito Aedes aegypti can be inseminated and blood-feed. We next examined fecundity, fertility, and the storage of sperm in the female reproductive tract in “young” (30-41 hours-old) and “old” (2- and 3-week-old) females, finding that blood-feeding began at 14 hours, and mating at ∼24 hours post-emergence. Although young females consumed smaller blood quantities and stored fewer sperm, they were similarly fertile to 4-day-old controls. Old females, however, suffered significant declines in fecundity by 2 weeks of age. Our results show that female Ae. aegypti start to become sexually receptive 1 day after their emergence, but can ingest blood much sooner, suggesting that mating is not a prerequisite to blood-feeding, and that females can ingest an arbovirus infected blood-meal shortly after emergence.

Distribution and role of d-glutamate, a novel d-amino acid identified in animals, in the reproductive tissues of male kuruma prawn Marsupenaeus japonicus.

Some aquatic invertebrates contain free d-alanine. We previously showed copious amounts of free d-glutamate, a novel d-amino acid, in the tissue of the male reproductive organs of Marsupenaeus japonicus. Herein, we clarified the distribution and potential role of d-glutamate and d-alanine in male reproductive tissues, namely the testis, vas deferens and seminal receptacle at different growth stages of M. japonicus. The percentage of d-glutamate to total glutamate was over 50% in these tissues. In particular, the content of d-glutamate was the most abundant in the vas deferens, the ratio of d-glutamate to total glutamate was approximately 80%. In contrast, d-alanine content was the lowest in the vas deferens among these tissues. d-Glutamate content was the highest when the prawn weighed 12g, indicating that d-glutamate is actively synthesized in the younger stage. Our findings suggest that d-glutamate plays an important role in the reproductive functions of M. japonicus.

Effects of Semen Dosage and Insemination Frequency on Fertility and Hatchability in Horasi Chicken Ecotype

The objective of this study was to assess the effect of Horasi chicken ecotype semen dilution, insemination dosage, and frequency of insemination on spermatozoa fertility potentials (hatchability and fertility). Twenty adult hens and four cockerels were used in a 2×2×2 factorial experiment. The factors were semen type (undiluted versus diluted semen), insemination volume (0.5 versus 0.1 ml), and insemination frequency (once versus twice inseminations per week). Egg fertility and hatchability among semen type, semen volume and insemination frequency varied from 68.35 ± 2.10 to 82.20 ± 2.29, and 59.38 ± 2.15 to 86.87 ± 2.57; 70.99 ± 2.45 to 79.56 ± 2.62, and 69.33 ± 3.88 to 76.92 ± 3.83; 67.41 ± 1.99 to 83.15 ± 2.06, and 68.53 ± 4.16 to 77.73 ± 3.40 respectively. The type of semen significantly (P ˂0.05) affected both fertility and hatchability. Higher fertility was recorded in hens inseminated with diluted fresh semen than those inseminated using undiluted fresh semen in all semen volumes and insemination frequencies. Insemination volume and insemination frequency had a significant (P ˂0.05) effect only on fertility. Higher egg fertility was observed in hens inseminated with 0.5mL of semen compared to those inseminated using 0.1mL of semen irrespective of semen type and insemination frequency. Also, hens inseminated twice a week had higher egg fertility in comparison to those inseminated once a week irrespective of semen volume and semen type. From the results obtained, it is concluded that the BPSE improved the fertilizing potential of fresh stored sperm and subsequent hatchability, while inseminating dose and insemination frequency only affected fertility. Thus, twice weekly insemination with diluted semen using 0.5mL of semen will maximize fertility and hatchability of Horasi chicken ecotype eggs.

Honey bee retinue workers respond similarly to queens despite seasonal differences in Queen Mandibular Pheromone (QMP) signaling.

Honey bee colonies maintain viable queens in part through communication with Queen Mandibular Pheromone (QMP), a mixture that signals the queen's presence and reproductive quality to workers. In turn, workers are thought to provide retinue queen care or replace queens partially based on QMP profiles. We examined the effects of seasonal dearth (overwintering in a warm subtropical location) on queen-worker interactions. Retinue worker responses to continuously ovipositing queens were considered in view of QMP signaling and queen reproductive quality. QMP signaling was estimated from QMP residues recovered from nest worker bodies, which is the primary mode of QMP transfer from the queen to the colony at large. QMP residues varied seasonally but not at all with queen reproductive quality (spermatheca sperm storage, ovary protein and lipid contents). 9-HDA and 9-ODA were lower in January than other months. HOB decreased from July to January, while HVA, a component associated with mated queens, increased sharply in January. Despite these seasonal signaling differences, retinue workers attended queens at similar levels through the months. In terms of reproductive quality, queens did not differ over the months in matedness (spermatheca sperm storage) or physiological age (protein carbonyl content), but varied in nutrient allocation to reproductive and non-reproductive tissues. Queen ovaries contained more protein in September than in November, and more lipid in July and September than in November and January. Queen fat bodies had more protein in July than September or November, but less lipid in July and September than November or January. Retinue worker responses did not vary with seasonal QMP changes, but reflected overall continuous brood rearing efforts and queen matedness throughout the year. The absence of seasonal differences in worker responses to QMP should be considered in the broader context of continuous reproductive efforts in warm subtropical colonies.

Male-derived transcripts isolated from the mated female reproductive tract in Drosophila melanogaster.

In species with internal fertilization, sperm, and seminal fluid are transferred from male to female during mating. While both sperm and seminal fluid contain various types of molecules, including RNA, the role of most of these molecules in the coordination of fertilization or in other possible functions is poorly understood. In Drosophila, exosomes from the accessory gland, which produces seminal fluid, are transferred to females, but their potential cargoes have not been described. Moreover, while the RNA composition of sperm has been described in several mammalian species, little work on this problem has occurred in Drosophila. Here we use single nucleotide polymorphism differences between males and females from a set of highly inbred lines of D. melanogaster, and transcriptome data from the female reproductive tract, sperm, testis, and accessory gland, to investigate the potential origin, male vs female, RNA molecules isolated from 3 female reproductive tract organs, the seminal receptacle and spermatheca, which store sperm, and the parovaria, which does not. We find that mated females carry male-derived transcripts from many genes, including those that are markers of the accessory gland and known seminal fluid proteins. Our observations also support the idea that intact sperm transcripts can be isolated from the female sperm storage organs.

Is glycerol a good cryoprotectant for sperm cells? New exploration of its toxicity using avian model

Glycerol is a cryoprotectant used widely for the cryopreservation of animal sperm, but it is linked to a decrease in fertility. The mechanism underlying the negative effects of glycerol remains unclear. Therefore, in this study, we aimed to gain a better understanding by using the chicken model. First, we investigated the impact of increasing the concentration of glycerol during insemination on hen fertility. Our findings revealed that 2% glycerol resulted in partial infertility, while 6% glycerol led to complete infertility. Subsequently, we examined the ability of sperm to colonize sperm storage tubules (SST) during in vivo insemination and in vitro incubation. The sperm used in the experiment were stained with Hoechst and contained 0, 2, or 6% glycerol. Furthermore, we conducted perivitelline membrane lysis tests and investigated sperm motility, mitochondrial function, ATP concentration, membrane integrity, and apoptosis after 60 min of incubation with different glycerol concentrations (0%, 1%, 2%, 6%, and 11%) at two temperatures to simulate pre-freezing (4 °C) and post-insemination (41 °C) conditions. Whereas 2% glycerol significantly reduced 50% of sperm containing SST, 6% glycerol completely inhibited SST colonization in vivo. On the other hand, in vitro incubation of sperm with SST revealed no effect of 2% glycerol, and 6% glycerol showed only a 17% reduction in sperm-filled SST. Moreover, glycerol reduced sperm-egg penetration rates and also affected sperm motility, bioenergetic metabolism, and cell death at 4 °C. These effects were observed when the concentration of glycerol exceeded 6%. Furthermore, at 41 °C, glycerol caused even greater damage, particularly in terms of reducing sperm motility. These data altogether reveal important effects of glycerol on sperm biology, sperm migration, SST colonization, and oocyte penetration. This suggests that glycerol plays a role in reducing fertility and presents opportunities for improving sperm cryopreservation.

Extracellular vesicle-coupled miRNA profiles of chicken seminal plasma and their potential interaction with recipient cells

The presence of EVs in seminal plasma (SPEVs) suggests their involvement on fertility via transmitting information between the original cells and recipient cells. SPEVs-coupled miRNAs have been shown to affect sperm motility, maturation, and capacitation in mammals, but rarely in poultry species. The present study aims to reveal the profile of SPEVs miRNAs and their potential effect on sperm storage and function in poultry. The SPEVs was successfully isolated from 4 different chicken breeds by ultracentrifugation and verified. Deep sequencing of SPEVs small RNA library of each breed identified 1077 miRNAs in total and 563 shared ones. The top 10 abundant miRNAs (such as miR-10-5p, miR-100-5p, and miR-10a-5p etc.) accounted for around 60% of total SPEVs miRNA reads and are highly conserved across species, predisposing their functional significance. Target genes prediction and functional enrichment analysis indicated that the most abundantly expressed miRNAs may regulate pathways like ubiquitin-mediated proteolysis, endocytosis, mitophagy, glycosphingolipid biosynthesis, fatty acid metabolism, and fatty acid elongation. The high abundant SPEVs-coupled miRNAs were found to target 107 and 64 functionally important mRNAs in the potential recipient cells, sperm and sperm storage tubules (SST) cells, respectively. The pathways that enriched by target mRNAs revealed that the SPEVs-coupled miRNA may rule the fertility by affecting the sperm maturation and regulating the female's immune response and lipid metabolism. In summary, this study presents the distinctive repertoire of SPEVs-coupled miRNAs, and extends our understanding about their potential roles in sperm maturation, capacitation, storage, and fertility, and may help to develop new therapeutic strategies for male infertility and sperm storage.

Mating in the cold. Prolonged sperm storage provides opportunities for forced copulation by male bats during winter.

In a wide range of heterothermic mammals, hibernation interrupts the reproductive cycle by forcing reproductive delays. In hibernating bats with delayed fertilization, an opportunity for sperm competition is enhanced by extending a time-window between copulations and fertilization. In order to achieve greater fertilization success, males are expected to show adaptations for sperm competition by increasing their opportunities for mating over an extended period. We aimed to clarify the physiological and behavioral characteristics of male bats experiencing increased risks of sperm competition. We investigated the characteristics of the reproductive cycle of the little horseshoe bat (Rhinolophus cornutus), and examined whether males retain reproductive physiology related to sexual behavior, and attempt to copulate with females even during the hibernation period. Field observations and histological examinations of the reproductive cycle confirmed that females, having mated in the autumn, store spermatozoa in the uterus during hibernation and give birth in the early summer to just one offspring per year, thus males face a low certainty of successful fertilization. Although their testes regressed rapidly and their testosterone levels were lower during winter than in autumn, males stored motile spermatozoa in their cauda epididymides from autumn throughout the winter. During hibernation, we found that males occasionally aroused from torpor and attempted to mate forcibly with torpid females. Forced copulations appear to increase a male's chances of obtaining a mate while avoiding pre-copulatory female choice. Epididymal sperm storage could be advantageous for males in allowing them to extend their potential mating period even though their testes have regressed. We also found that some hibernating nulliparous females were ready for fertilization in spring after hibernation, whereas few parous females appeared in the same roost. In contrast to males, forced copulations would be maladaptive for females because they cannot opt for higher-quality males while in torpor. Females that have experienced sexual coercion when young may subsequently avoid hibernacula where adult males are present.

Mating- and oviposition-dependent changes of the spermatheca and colleterial glands in the pest termite Cryptotermes brevis (Blattaria, Isoptera, Kalotermitidae).

The spermatheca and colleterial glands of female insects are organs associated with the reproductive system, responsible for sperm storage and secretion of egg coverings, respectively. Here we compared the development, secretory activity, and chemical nature of the secretion in the spermatheca and colleterial glands of different-aged females of the drywood termite Cryptotermes brevis. We also provide the ultrastructure of these organs in alate females. These structures have been poorly investigated in termites when compared to other eusocial insects (Hymenoptera) and termite-related dictyopterans (mantises and cockroaches). The spermatheca of C. brevis comprises a cone-shaped structure, connected to the genital chamber by a short duct. The colleterial glands, in turn, are divided into anterior and posterior tubules, each showing a basal trunk, and join into a common duct. Histological and histochemical analyses showed that the secretion of proteins and polysaccharides by the spermatheca takes place before pairing, but increases as females mate and store sperm. Colleterial glands of alates showed non-synchronous secretory activity, but the synthesis of products increased in egg-laying queens, together with the epithelium height. Ultrastructure of the spermatheca and colleterial glands revealed epithelia composed of class III secretory cells. Richness of mitochondria and electron-dense secretion in the spermatheca indicates synthesis and transport of content. Presence and absence of colleterial gland secretion in different individuals may reflect variable maturation stages of the females and secretory cells. Assuming that termites are iteroparous, the development and secretion of the spermatheca and colleterial glands play a crucial role for C. brevis queens.

Immunoregulatory mechanisms between epithelial clear cells and mononuclear phagocytes in the epididymis.

One of the most intriguing aspects of male reproductive physiology is the ability of the epididymis to prevent the mounting of immune responses against the onslaught of foreign antigens carried by spermatozoa while initiating very efficient immune responses versus stressors. Epithelial clear cells are strategically positioned to work in a concerted manner with region-specific heterogeneous subsets of mononuclear phagocytes to survey the epididymal barrier and regulate the balance between inflammation and immune tolerance in the post-testicular environment. This review aims to describe how clear cells communicate with mononuclear phagocytes to contribute to the unique immune environment in which sperm mature and are stored in the epididymis. A comprehensive systematic review was performed. PubMed was searched for articles specific to clear cells, mononuclear phagocytes, and epididymis. Articles that did not specifically address the target material were excluded. In this review, we discuss the unexpected roles of clear cells, including the transfer of new proteins to spermatozoa via extracellular vesicles and nanotubes as they transit along the epididymal tubule; and we summarize the immune phenotype, morphology, and antigen capturing, processing, and presenting abilities of mononuclear phagocytes. Moreover, we present the current knowledge of immunoregulatory mechanisms by which clear cells and mononuclear phagocytes may contribute to the immune-privileged environment optimal for sperm maturation and storage. Notably, we provide an in-depth characterization of clear cell-mononuclear phagocyte communication networks in the steady-state epididymis and in the presence of injury. This review highlights crucial concepts of mucosal immunology and cellcell interactions, all of which are critical but understudied facets of human male reproductive health.

Recovery, storage, and preparation of epididymal and vas deferens sperm for insemination, cryopreservation, and shipping

Current technology allows preservation of sperm from testes and the distal reproductive tract if harvested after death determined largely by environmental and handling conditions (e.g. how long sperm remain viable within their nurturing structures postmortem) after death. Pregnancies are established using nonejaculated and even immotile sperm with appropriate preparation. There are very simple techniques available that can be employed by any practitioner to recover and prepare sperm from testes and the distal reproductive tract. This paper focuses on techniques for recovery, storage, and preparation of epididymal and vas deferens sperm, and techniques for shipping and cryopreservation.

Minimizing sperm oxidative stress using nanotechnology for breeding programs in rams

BackgroundArtificial insemination (AI) is a routine breeding technology in animal reproduction. Nevertheless, the temperature-sensitive nature and short fertile lifespan of ram sperm samples hamper its use in AI. In this sense, nanotechnology is an interesting tool to improve sperm protection due to the development of nanomaterials for AI, which could be used as delivery vehicles. In this work, we explored the feasibility of vitamin E nanoemulsion (NE) for improving sperm quality during transport.ResultsWith the aim of evaluating this proposal, ejaculates of 7 mature rams of Manchega breed were collected by artificial vagina and extended to 60 × 106 spz/mL in Andromed®. Samples containing control and NE (12 mmol/L) with and without exogenous oxidative stress (100 µmol/L Fe2+/ascorbate) were stored at 22 and 15 ºC and motility (CASA), viability (YO-PRO/PI), acrosomal integrity (PNA-FITC/PI), mitochondrial membrane potential (Mitotracker Deep Red 633), lipoperoxidation (C11 BODIPY 581/591), intracellular reactive oxygen species (ROS) production and DNA status (SCSA®) monitored during 96 h. Our results show that NE could be used to maintain ram spermatozoa during transport at 15 and 22 ºC for up to 96 h, with no appreciable loss of kinematic and physiological characteristics of freshly collected samples.ConclusionsThe storage of ram spermatozoa in liquid form for 2–5 d with vitamin E nanoemulsions may lead more flexibility to breeders in AI programs. In view of the potential and high versatility of these nanodevices, further studies are being carried out to assess the proposed sperm preservation medium on fertility after artificial insemination.Graphical

The reproductive tract of the black soldier fly (Hermetia illucens) is highly differentiated and suggests adaptations to sexual selection

AbstractThe reproductive biology of the black soldier fly (BSF), Hermetia illucens (L.) (Diptera: Stratiomyidae), was investigated in males and females with a focus on how sperm is handled by males before – and by females after – copulation. As this insect has great economic importance for protein production from agri‐food wastes, its reproduction needs to be precisely known. A detailed description of male and female reproductive organs was made, and sperm were counted in male and female storage organs. Measures of testis and sperm counts were performed in males of various ages and their dynamics was compared to the ovaries of females. Both male and female tracts were long, and consisted of various successive parts. In males, testes fill the vas deferens with mature sperm, that are tangled as ‘windrows’, and sperm pass successively through a ‘studded pipe’ and three phallic ‘wands’ before being transferred to females. In virgin males, mean (± SEM) sperm number increased from approximately 9700 (± 1400, n = 5) to 39600 (± 3470, n = 13) in 20 days, and testes gradually decreased in size, indicating continuous spermatogenesis. Sperm cells are long, more than 3 mm. During copulation, sperm are deposited by phallic ‘wands’ at the base of each spermatheca in a smooth tube followed by a ‘fishnet canal’ at the top of which they accumulate before complete storage. They then pass through a ringed canal, an elbow, and a rigid rod strewn with glands, before reaching the spermathecal reservoir. Females store approximately 680 spermatozoa after one mating in each spermathecal reservoir. Such complex sperm storage organs of females may indicate strong female post‐mating selection, and reflect competition for long and numerous sperm in this species, in which female multiple matings are suspected. Besides its economical interest, BSF is an appealing model for further investigations on sexual selection.

Additional of coconut water and glycerol in sperm storage spermatozoa motility and viability of comet fish, Carassius auratus

This study aims to determine the effect of giving coconut water and glycerol to comet fish (Carassius auratus) sperm storage on the motility, viability of comet fish (Carassius auratus) sperm and the degree of fertilization of comet fish eggs. This research was carried out at the Fish Hatchery Laboratory, Faculty of Marine and Fisheries, Universitas Syiah Kuala. This research method used was a Complete Randomized Design (CRD) consisting of four treatments with five replications, namely (P0) Sperm + 100% NaCl, (P1) Sperm + 50% coconut water + 50% glycerol, (P2) Sperm + 60% coconut water + 40% glycerol, and (P3) Sperm + 70% coconut water + 30% glycerol. The results showed that adding coconut water and glycerol to Storage of comet fish sperm had a significant effect (<0.05) on the value of motility and viability. Based on the results of the study, it can be concluded that the highest values of post-cryopreservation sperm motility and viability in comet fish in this study were found in the P2 treatment with a concentration of 60% d coconut water + 40% glycerol.

Fission-fusion dynamics in the social networks of a North American pitviper.

Many animal species exist in fission-fusion societies, where the size and composition of conspecific groups change spatially and temporally. To help investigate such phenomena, social network analysis (SNA) has emerged as a powerful conceptual and analytical framework for assessing patterns of interconnectedness and quantifying group-level interactions. We leveraged behavioral observations via radiotelemetry and genotypic data from a long-term (>10 years) study on the pitviper Crotalus atrox (western diamondback rattlesnake) and used SNA to quantify the first robust demonstration of social network structures for any free-living snake. Group-level interactions among adults in this population resulted in structurally modular networks (i.e., distinct clusters of interacting individuals) for fidelis use of communal winter dens (denning network), mating behaviors (pairing network), and offspring production (parentage network). Although the structure of each network was similar, the size and composition of groups varied among them. Specifically, adults associated with moderately sized social groups at winter dens but often engaged in reproductive behaviors-both at and away from dens-with different and fewer partners. Additionally, modules formed by individuals in the pairing network were frequently different from those in the parentage network, likely due to multiple mating, long-term sperm storage by females, and resultant multiple paternity. Further evidence for fission-fusion dynamics exhibited by this population-interactions were rare when snakes were dispersing to and traversing their spring-summer home ranges (to which individuals show high fidelity), despite ample opportunities to associate with numerous conspecifics that had highly overlapping ranges. Taken together, we show that long-term datasets incorporating SNA with spatial and genetic information provide robust and unique insights to understanding the social structure of cryptic taxa that are understudied.

Collective cell dynamics and luminal fluid flow in the epididymis: A mechanobiological perspective.

The mammalian epididymis is a specialized duct system that serves a critical role in sperm maturation and storage. Its distinctive, highly coiled tissue morphology provides a unique opportunity to investigate the link between form and function in reproductive biology. Although recent genetic studies have identified key genes and signaling pathways involved in the development and physiological functions of the epididymis, there has been limited discussion about the underlying dynamic and mechanical processes that govern these phenomena. In this review, we aim to address this gap by examining two key aspects of the epididymis across its developmental and physiological phases. First, we discuss how the complex morphology of the Wolffian/epididymal duct emerges through collective cell dynamics, including duct elongation, cell proliferation, and arrangement during embryonic development. Second, we highlight dynamic aspects of luminal fluid flow in the epididymis, essential for regulating the microenvironment for sperm maturation and motility, and discuss how this phenomenon emerges and interplays with epididymal epithelial cells. This review not only aims to summarize current knowledge but also to provide a starting point for further exploration of mechanobiological aspects related to the cellular and extracellular fluid dynamics in the epididymis.

An oviduct glycan increases sperm lifespan by diminishing the production of ubiquinone and reactive oxygen species†.

Sperm storage by females after mating for species-dependent periods is used widely among animals with internal fertilization to allow asynchrony between mating and ovulation. Many mammals store sperm in the lower oviduct where specific glycans on oviduct epithelial cells retain sperm to form a reservoir. Binding to oviduct cells suppresses sperm intracellular Ca2+ and increases sperm longevity. We investigated the mechanisms by which a specific oviduct glycan, 3-O-sulfated Lewis X trisaccharide (suLeX), prolongs the lifespan of porcine sperm. Using targeted metabolomics, we found that binding to suLeX diminishes the abundance of 4-hydroxybenzoic acid, the precursor to ubiquinone (also known as Coenzyme Q), 30min after addition. Ubiquinone functions as an electron acceptor in the electron transport chain (ETC). 3-O-sulfated Lewis X trisaccharide also suppressed the formation of fumarate. A component of the citric acid cycle, fumarate is synthesized by succinate-coenzyme Q reductase, which employs ubiquinone and is also known as Complex II in the ETC. Consistent with the reduced activity of the ETC, the production of harmful reactive oxygen species (ROS) was diminished. The enhanced sperm lifespan in the oviduct may be because of suppressed ROS production because high ROS concentrations have toxic effects on sperm.

UBR4 deficiency causes male sterility and testis abnormal in Drosophila.

It has been established that UBR4 encodes E3 ubiquitin ligase, which determines the specificity of substrate binding during protein ubiquitination and has been associated with various functions of the nervous system but not the reproductive system. Herein, we explored the role of UBR4 on fertility with a Drosophila model. Different Ubr4 knockdown flies were established using the UAS/GAL4 activating sequence system. Fertility, hatchability, and testis morphology were studied, and bioinformatics analyses were conducted. Our results indicated that UBR4 deficiency could induce male sterility and influent egg hatchability in Drosophila. We found that Ubr4 deficiency affected the testis during morphological analysis. Proteomics analysis indicated 188 upregulated proteins and 175 downregulated proteins in the testis of Ubr4 knockdown flies. Gene Ontology analysis revealed significant upregulation of CG11598 and Sfp65A, and downregulation of Pelota in Ubr4 knockdown flies. These proteins were involved in the biometabolic or reproductive process in Drosophila. These regulated proteins are important in testis generation and sperm storage promotion. Bioinformatics analysis verified that UBR4 was low expressed in cryptorchidism patients, which further supported the important role of UBR4 in male fertility. Overall, our findings suggest that UBR4 deficiency could promote male infertility and may be involved in the protein modification of UBR4 by upregulating Sfp65A and CG11598, whereas downregulating Pelota protein expression.

Sperm storage in Crotalus durissus (Serpentes: Crotalinae): histological insights about the female reproductive tract of pit vipers

Sperm storage in Crotalus durissus (Serpentes: Crotalinae): histological insights about the female reproductive tract of pit vipers