A decade of the sperm‐washing programme: correlation between markers of HIV and seminal parameters

Objectives

The aim of the study was to use a decade of experience of sperm washing to assess the effect of HIV disease on semen parameters and to highlight the continuing importance of risk reduction when some controversially advocate the safety of timed unprotected intercourse for conception in the ‘stable’ HIV‐positive man.

Methods

Semen parameters of 439 fresh samples used for sperm washing/intrauterine insemination (IUI) were correlated against markers of HIV disease [CD4 cell count, viral load (VL), duration of HIV infection and use of antiretroviral therapy] and the risk of detectable virus in semen was assessed.

Results

A significant positive correlation was observed between CD4 cell count and total sperm count, progressive motility, post‐preparation/insemination concentration, progressive motility and total motile count inseminated (TMCI), and a significant negative correlation was observed between CD4 cell count and normal sperm morphology (Spearman's correlation; P<0.05). There was no significant difference in any parameter between samples in which VL was detectable and those in which it was undetectable. The use of highly active antiretroviral therapy (HAART) significantly decreased total sperm count, progressive motility, post‐preparation count and TMCI and significantly increased proportion of abnormal forms (Mann–Whitney tests; P<0.05). There was a significant negative correlation between duration of HAART use and concentration, total sperm count and post‐preparation motility and between years since diagnosis and post‐preparation motility. In 9.7% of IUI cycles performed with fresh sperm in men on HAART with undetectable VL, detectable HIV was found in either pre‐ or post‐wash seminal samples.

Conclusion

Our data suggest a negative effect of low CD4 cell count and the use of HAART on semen. The significant proportion of ‘stable’; men with undetectable serum VL but virus in semen confirms the continued importance of such risk reduction.     

From the Cover: Female promiscuity promotes the evolution of faster sperm in cichlid fishes

Sperm competition, the contest among ejaculates from rival males to fertilize ova of a female, is a common and powerful evolutionary force influencing ejaculate traits. During competitive interactions between ejaculates, longer and faster spermatozoa are expected to have an edge; however, to date, there has been mixed support for this key prediction from sperm competition theory. Here, we use the spectacular radiation of cichlid fishes from Lake Tanganyika to examine sperm characteristics in 29 closely related species. We provide phylogenetically robust evidence that species experiencing greater levels of sperm competition have faster-swimming sperm. We also show that sperm competition selects for increases in the number, size, and longevity of spermatozoa in the ejaculate of a male, and, contrary to expectations from theory, we find no evidence of trade-offs among sperm traits in an interspecific analysis. Also, sperm swimming speed is positively correlated with sperm length among, but not within, species. These different responses to sperm competition at intra- and interspecific levels provide a simple, powerful explanation for equivocal results from previous studies. Using phylogenetic analyses, we also reconstructed the probable evolutionary route of trait evolution in this taxon, and show that, in response to increases in the magnitude of sperm competition, the evolution of sperm traits in this clade began with the evolution of faster (thus, more competitive) sperm.     

Isolation and characterization of specific rat epididymal proteins.

The partial purification and characterization of specific rat epididymal proteins (SEP) is reported. Starting from the cytosol fraction obtained from epididymal homogenates, protein C was purified 15-fold and proteins D--E were purified 19-fold. The molecular weight, determined by molecular sieving, of protein C was 22,400 while that of D--E was 37,000. These proteins stained as glycoproteins with periodic acid--Schiff reagent. The isoelectric point of protein D was 5.13 while that of protein E was 4.95. Protein C separated into 3 bands during isoelectric focussing. The major component focussed at 5.56 and the two minor components at pH 5.38 And 5.79. Using a specific antiserum we could confirm the organ specificity of SEP and their androgen-dependence.     

Acp36DE is required for uterine conformational changes in mated Drosophila females

In a multitude of animals with internal fertilization, including insects and mammals, sperm are stored within a female''s reproductive tract after mating. Defects in the process of sperm storage drastically reduce reproductive success. In Drosophila males, “Acp” seminal proteins alter female postmating physiology and behavior, and are necessary for several aspects of sperm storage. For example, Acps cause a series of conformational changes in the mated female''s reproductive tract that occur during and immediately after mating. These conformational changes have been hypothesized to aid both in the movement of sperm within the female and in the subsequent storage of those sperm. We used RNAi to systematically knock down several Acps involved in sperm storage to determine whether they played a role in the mating-induced uterine conformational changes. Mates of males lacking the glycoprotein Acp36DE, which is needed for the accumulation of sperm in the storage organs, fail to complete the full sequence of the conformational changes. Our results show that uterine conformational changes are important for proper accumulation of sperm in storage and identify a seminal protein that mediates these changes. Four Acps included in this study, previously shown to affect sperm release from storage (CG9997, CG1656, CG1652, and CG17575), are not necessary for uterine conformational changes to occur. Rather, consistent with their role in later steps of sperm storage, we show here that their presence can affect the outcome of sperm competition situations.     

Sperm chemotaxis, fluid shear, and the evolution of sexual reproduction

Chemical communication is fundamental to sexual reproduction, but how sperm search for and find an egg remains enigmatic. For red abalone (Haliotis rufescens), a large marine snail, the relationship between chemical signaling and fluid motion largely determines fertilization success. Egg-derived attractant plumes are dynamic, changing their size and shape in response to unique combinations of physical and chemical environmental features. Attractant plumes that promote sexual reproduction, however, are limited to a precise set of hydrodynamic conditions. Performance-maximizing shears are those that most closely match flows in native spawning habitats. Under conditions in which reproductive success is chronically limited by sperm availability, gametes are under selection for mechanisms that increase sperm-egg encounter. Here, chemoattraction is found to provide a cheap evolutionary alternative for enhancing egg target size without enlarging cytoplasmic and/or cell volume. Because egg signaling and sperm response may be tuned to meet specific fluid-dynamic constraints, shear could act as a critical selective pressure that drives gamete evolution and determines fitness.     

High-throughput lensfree 3D tracking of human sperms reveals rare statistics of helical trajectories

Dynamic tracking of human sperms across a large volume is a challenging task. To provide a high-throughput solution to this important need, here we describe a lensfree on-chip imaging technique that can track the three-dimensional (3D) trajectories of > 1,500 individual human sperms within an observation volume of approximately 8–17 mm³. This computational imaging platform relies on holographic lensfree shadows of sperms that are simultaneously acquired at two different wavelengths, emanating from two partially-coherent sources that are placed at 45° with respect to each other. This multiangle and multicolor illumination scheme permits us to dynamically track the 3D motion of human sperms across a field-of-view of > 17 mm² and depth-of-field of approximately 0.5–1 mm with submicron positioning accuracy. The large statistics provided by this lensfree imaging platform revealed that only approximately 4–5% of the motile human sperms swim along well-defined helices and that this percentage can be significantly suppressed under seminal plasma. Furthermore, among these observed helical human sperms, a significant majority (approximately 90%) preferred right-handed helices over left-handed ones, with a helix radius of approximately 0.5–3 μm, a helical rotation speed of approximately 3–20 rotations/s and a linear speed of approximately 20–100 μm/s. This high-throughput 3D imaging platform could in general be quite valuable for observing the statistical swimming patterns of various other microorganisms, leading to new insights in their 3D motion and the underlying biophysics.     

Multiple deleterious effects of experimentally aged sperm in a monogamous bird

Sperm aging is known to be detrimental to reproductive performance. However, this apparently general phenomenon has seldom been studied in an evolutionary context. The negative impact of sperm aging on parental fitness should constitute a strong selective pressure for adaptations to avoid its effects. We studied the impact of sperm aging on black-legged kittiwakes (Rissa tridactyla), a monogamous seabird. Kittiwakes comprise a model system because (i) of evidence that females eject their mates' sperm to prevent fertilization by sperm that would be old and degraded by the time of fertilization and result in reduced reproductive performance and (ii) the lack of extra-pair fertilization in this species makes cryptic female choice an unlikely explanation of postcopulatory sperm ejection by females. We experimentally manipulated the age of the sperm fertilizing kittiwake eggs by fitting males with anti-insemination rings for variable periods of time preceding egg-laying. We found evidence that sperm aging negatively affected four sequential stages of reproduction: fertilization potential, rate of embryonic development, embryonic mortality, and chick condition at hatching. These results may be produced by a continuum of a single process of sperm aging that differentially affects various aspects of development, depending on the degree of damage incurred to the spermatozoa. The marked impact of sperm age on female fitness may thus drive postcopulatory sperm ejection by females. These results provide experimental evidence of deleterious effects of sperm aging on a nondomestic vertebrate, underlining its taxonomic generality and its potential to select for a wide array of adaptations.     

A network of interactions among seminal proteins underlies the long-term postmating response in Drosophila

Despite the importance of seminal proteins in fertility and their capacity to alter mated females'' physiology, the molecular pathways and networks through which they act have not been well characterized. Drosophila seminal fluid includes proteins that fall into biochemical classes conserved from insects to mammals, making it an excellent model with which to address this question. Drosophila seminal fluid also contains a “sex peptide” (SP, Acp70A) that plays a major role in regulating egg production and mating behavior in females for several days after mating. This long-term postmating response (LTR) initially requires the association of SP with sperm. The LTR also requires members of the conserved seminal protein classes (two lectins, a protease, and a cysteine-rich secretory protein). Here, we show that these seminal proteins function interdependently, regulating a three-step cascade (first, at the level of seminal protein transfer to the female; second, at the level of stability; and third, at the level of localization within females), leading to the normal localization of SP to sperm-storage organs. This localization is, in turn, necessary for successful induction of the LTR. The requirements for manifestation of the LTR in Drosophila establish the paradigm that multiple seminal proteins can exert their actions through a multistep, multicomponent network of interactions.     

Testicular volume is inversely correlated with nurturing-related brain activity in human fathers

Despite the well-documented benefits afforded the children of invested fathers in modern Western societies, some fathers choose not to invest in their children. Why do some men make this choice? Life History Theory offers an explanation for variation in parental investment by positing a trade-off between mating and parenting effort, which may explain some of the observed variance in human fathers’ parenting behavior. We tested this hypothesis by measuring aspects of reproductive biology related to mating effort, as well as paternal nurturing behavior and the brain activity related to it. Both plasma testosterone levels and testes volume were independently inversely correlated with paternal caregiving. In response to viewing pictures of one’s own child, activity in the ventral tegmental area—a key component of the mesolimbic dopamine reward and motivation system—predicted paternal caregiving and was negatively related to testes volume. Our results suggest that the biology of human males reflects a trade-off between mating effort and parenting effort, as indexed by testicular size and nurturing-related brain function, respectively.In modern Western societies, paternal involvement is associated with reduced child mortality and morbidity (1, 2), as well as improved social, psychological, and educational outcomes (3, 4). Despite this finding, there is remarkable variation in paternal involvement (5) and father absence has increased precipitously over the last half of the 20th century (3), which raises the question: Why do some men choose not to invest in their children?A branch of evolutionary theory known as Life History Theory posits a trade-off between mating and parenting effort (6–8). Given that organisms have finite amounts of energy to expend on reproduction, evolution optimizes the allocation of resources toward either mating or parenting so as to maximize fitness. Evidence in support of this trade-off is found throughout the animal kingdom, including humans (8). Although Life History Theory is traditionally invoked to explain differences between species, it has also been applied to explain individual differences within a species, including humans (9, 10). However, no study to date has investigated whether human anatomy and brain function reflect a trade-off between mating and parenting investment.Several lines of research suggest that testosterone may bias males toward a mating strategy and away from a parenting strategy (11). In humans, low levels of testosterone are associated with reduced libido (12), and high levels predict mating success (13). Within married couples, testosterone levels are negatively correlated with relationship quality and high levels predict divorce (14) as well as polygyny (15). In contrast, a decrease in testosterone accompanies fatherhood in several species (11, 16), including humans (13, 17), where variation in testosterone is inversely related to paternal involvement (13, 15). Experimental manipulation of testosterone suggests that high testosterone is causally associated with both increased mating effort and decreased parenting effort (18). Thus, decreases in testosterone may suppress mating effort that might detract from investment in the infant. A decrease in testosterone might also both suppress impulsive aggression and promote empathic responding toward a highly vulnerable infant, who shapes parental behavior mainly through crying (19–22).In addition to testosterone, both testicular size and function are related to mating strategies (reviewed in ref. 23). For example, among primates, monogamy and single-male polygyny are associated with smaller testes size compared with multimale, multifemale breeding systems. Presumably, female promiscuity selects for sperm competition and enlarged testes size in multimale, multifemale groups (24, 25). Intraspecific variation in testes size is related to reproductive success (26) and copulatory rates (27) in two different mammalian species, and one group claims to have shown that testes size predicts mating strategies in humans (28), although another group failed to replicate this finding (29). Although the testes produce testosterone, inter- and intraspecies differences in testes size likely reflect differences in sperm production more so than hormone production, because seminiferous tubules account for 70–80% of the volume of the testes and testes volume is more highly correlated with sperm count and quality than with testosterone levels (29–31). Thus, an inverse correlation between testes size and parenting effort would reflect a trade-off between spermatogenesis, a form of mating effort, and parental care. Here we investigate whether testes size explains variance in parenting effort over and above testosterone alone.If human fathers vary in their allocation of resources to parenting and mating, brain function should mediate this variability. Animal models point to the importance of the mesolimbic dopamine (DA) system in the appetitive drive to nurture offspring, with DA-producing cell bodies in the ventral tegmental area (VTA) projecting to the nucleus accumbens to motivate proactive care of infants (32). Activity in the VTA is consistently observed in parents exposed to child auditory (cry) and visual (face) stimuli (reviewed in ref. 33), and gray matter in the VTA increases in new mothers during the early postpartum period (34).These data suggest the following hypotheses: (i) testosterone and testes size will be negatively correlated with paternal investment; (ii) neural activity in the VTA in response to viewing pictures of one’s own child will predict paternal investment; and (iii) testosterone and testes size will be negatively correlated with neural activity in the VTA. To test these hypotheses, we recruited biological fathers of children age 1 or 2 y, and assessed mother- and father-reported paternal caregiving and desired levels of caregiving, as well as testes volume, plasma testosterone levels, and brain activity while fathers viewed pictures of their child.     

Ca2+ ionophore A23187 can make mouse spermatozoa capable of fertilizing in vitro without activation of cAMP-dependent phosphorylation pathways

Ca²⁺ ionophore A23187 is known to induce the acrosome reaction of mammalian spermatozoa, but it also quickly immobilizes them. Although mouse spermatozoa were immobilized by this ionophore, they initiated vigorous motility (hyperactivation) soon after this reagent was washed away by centrifugation. About half of live spermatozoa were acrosome-reacted at the end of 10 min of ionophore treatment; fertilization of cumulus-intact oocytes began as soon as spermatozoa recovered their motility and before the increase in protein tyrosine phosphorylation, which started 30–45 min after washing out the ionophore. When spermatozoa were treated with A23187, more than 95% of oocytes were fertilized in the constant presence of the protein kinase A inhibitor, H89. Ionophore-treated spermatozoa also fertilized 80% of oocytes, even in the absence of HCO₃⁻, a component essential for cAMP synthesis under normal in vitro conditions. Under these conditions, fertilized oocytes developed into normal offspring. These data indicate that mouse spermatozoa treated with ionophore are able to fertilize without activation of the cAMP/PKA signaling pathway. Furthermore, they suggest that the cAMP/PKA pathway is upstream of an intracellular Ca²⁺ increase required for the acrosome reaction and hyperactivation of spermatozoa under normal in vitro conditions.Mammalian spermatozoa, unlike spermatozoa of many other animals, are not able to fertilize on leaving the male body. They must undergo physiological changes, collectively called “capacitation,” to become fertilization-competent. Under normal conditions, sperm capacitation takes place within the female tract, but it can also occur in chemically defined media, as first demonstrated by Toyoda et al. (1) in the mouse. Although compositions of media necessary for successful in vitro capacitation vary between species, most are basically modified Tyrode’s and Krebs–Ringer’s solutions containing HCO₃⁻ and Ca²⁺, supplemented with energy metabolites and a cholesterol acceptor such as serum albumin. Capacitation enables spermatozoa to undergo the acrosome reaction and to exhibit vigorous motility called hyperactivation (2, 3). Both the acrosome reaction and hyperactivation are believed to be essential for successful sperm penetration into oocytes (4). Molecular changes associated with capacitation include an increase in intracellular pH (pH_i) (5), an increase in intracellular Ca²⁺ concentration [Ca²⁺]_i (6), activation of a cAMP/PKA pathway (7, 8), hyperpolarization of the sperm plasma membrane potential (9–11), loss of membrane cholesterol (12, 13) and modifications of other membrane lipids (14), and an increase in protein tyrosine phosphorylation (8, 15). How these events interact with each other to render spermatozoa capable of initiating the acrosome reaction and hyperactivation is not well understood. Recent studies using gene knock-out mice revealed that both cAMP- (14–17) and Ca²⁺-regulated signaling pathways (16–18) are intricately involved in these processes.Involvement of Ca²⁺ in the sperm acrosome reaction and in hyperactivation has been known for a long time (4). Ca²⁺ ionophore, which transports extracellular Ca²⁺ into cells or releases Ca²⁺ from intracellular stores (19), induces increased respiration (20), motility (21), and the acrosome reaction (22) in mammalian spermatozoa. Several studies have shown that Ca²⁺ ionophore A23187 increases intracellular Ca²⁺ concentration excessively, rendering spermatozoa immotile (23–26). However, immobilized spermatozoa are not dead, as demonstrated by Suarez et al. (25), who found that spermatozoa could regain motility when high concentrations of BSA were added to the medium. The high affinity of BSA for hydrophobic A23187 could explain this recovery. However, the question as to whether these spermatozoa are capable of pursuing their physiological function (fertilization) remained unanswered. We report here that mouse spermatozoa treated with ionophore A23178 did indeed become immotile, but soon after the ionophore was removed, they began to move vigorously (hyperactivated) and quickly fertilized oocytes. More surprisingly, ionophore-treated spermatozoa fertilize oocytes under the constant presence of H89, a PKA inhibitor, and also in the absence of HCO₃⁻ in the medium, an ion that is absolutely necessary for fertilization under normal in vitro conditions (27).     

High endogenous melatonin concentrations enhance sperm quality and short-term in vitro exposure to melatonin improves aspects of sperm motility

Although human seminal fluid contains melatonin and spermatozoa reportedly possess membrane melatonin receptors, there are no experimental studies that have ascertained the relationship between melatonin and male infertility. This study evaluated whether urinary 6-sulfatoxymelatonin and urinary total antioxidant capacity correlate with different seminal parameters including sperm concentration, motility and morphology. Also, the in vitro effects of melatonin on human sperm motility were investigated. Semen samples from 52 men who were counselled for infertility were obtained. Sperm concentration was determined using the haemocytometer method, motility kinematic parameters were assessed using a computer-aided semen analysis system, while morphology and vitality were evaluated after Diff-Quick and Eosin-Nigrosin vital staining, respectively. For the quantification of urinary 6-sulfatoxymelatonin, a commercial ELISA kit was used, and urinary total antioxidant capacity was evaluated by means of a colorimetric assay kit. For the in vitro effects of melatonin, samples were incubated for 30min in the presence or absence of 1mm melatonin. Both urinary 6-sulfatoxymelatonin and total antioxidant capacity levels positively correlated with sperm concentration, motility and morphology, as well as negatively correlated with the number of round cells. Additionally, 30-min exposure of sperm to 1mm melatonin improved the percentage of motile and progressively motile cells and decreased the number of static cells, thereby promoting the proportion of rapid cells. Therefore, melatonin improves semen quality, which is important because melatonin supplementation may be potentially used to obtain a successful assisted reproductive technique outcome.     

液氮蒸汽法、程序冷冻法冷冻精子复苏后活动能力比较

目的比较液氮蒸汽法和程序冷冻法冷冻保存的人类精子复苏后的活动能力。方法在同一种冷冻保护剂作用下,分别采用液氮蒸汽法和程序冷冻法对79份精液标本进行冷冻,比较复苏后精子的活动力。结果液氮蒸汽法冷冻的标本复苏后前向活动精子百分率和总活动率分别为43.2%±7.7%、52.2%±9.6%,用程序冷冻法冷冻者分别为44.2%±3.5%、52.9%±4.9%,两组相比,P均〉0.05;但与冷冻前的58.2%±5.6%、65.6%±5.7%相比均明显下降,P均〈0.05。结论采用液氮蒸汽法和程序冷冻法冷冻的人类精子复苏后活动能力相似,两种方法均可以用于常规的精子冷冻。     

Reproductive choices for couples with haemophilia

: Summary. The impact of having a child with an inherited bleeding disorder such as haemophilia can have a far-reaching effect on the individual as well as other close family members. This situation is further complicated in the case of human immunodeficiency (HIV) serodiscordant couples, where the haemophilic man is affected with HIV through infected blood products whilst his partner is seronegative and wanting to have children. It is essential that information on the effects of haemophilia, its inheritance, the possibilities of antenatal diagnosis, the consideration of selective abortion and the new reproductive opportunities available to these couples are made accessible so that an informed decision about proceeding with having a family can be made. Couples may wish to have a family through nonreproductive methods such as fostering or adoption. Alternatively, they may wish to remain childless. In this paper, the terms 'having children' and 'having a family' will refer to conception through biological reproduction. Pre-implantation genetic diagnosis (PGD) offers families at risk of having a child with certain inherited genetic disorders the opportunity to give birth to an unaffected child. It may be considered as an option for couples who would not wish to have prenatal diagnosis leading to possible termination of a pregnancy. Assisted conception techniques, such as 'sperm washing' or the use of 'donor sperm', offer serodiscordant couples affected by HIV a risk-reduced or risk-free opportunity, respectively, to have a child without infecting the mother, who could in turn infect the fetus by vertical transmission. This article, in addition to outlining the inheritance of haemophilia and the more common prenatal screening and diagnostic tests, discusses in more detail the latest reproductive opportunities available for families affected by haemophilia and considering having a family.     

Sperm quality before treatment in patients with early stage Hodgkin’s lymphoma enrolled in EORTC-GELA Lymphoma Group trials

Background

Although widely recommended, cryopreservation of sperm is sometimes not performed for patients with Hodgkin’s lymphoma because of presumed poor sperm quality related to the disease. We investigated sperm quality and factors determining it in untreated patients with early stage Hodgkin’s lymphoma.

Design and Methods

Of 2362 males who participated in EORTC H6–H9 trials, 474 (20%) had data available. Sperm quality was defined according to World Health Organization guidelines. Determining factors were studied by logistic regression analysis.

Results

The median sperm concentration was 40×10⁶/mL (range, 0–345×10⁶/mL) and the median motility 50% (range, 0–90%). Sperm quality was good (concentration ≥20×10⁶/mL and motility ≥50%), intermediate (concentration ≥5×10⁶/mL) and poor (concentration <5×10⁶/mL but >0) in 41%, 49% and 7% of patients, respectively. Three percent of the patients were azoospermic. No relation was found between sperm quality and age or clinical stage of the Hodgkin’s lymphoma, but B-symptoms and elevated erythrocyte sedimentation rate predicted poor sperm quality. The odds ratios for the association of poor sperm quality with the variables examined were: presence of B-symptoms, 2.77 (95% CI, 1.50–5.12; p=0.001); erythrocyte sedimentation rate of 50 mm/h or greater, 2.35 (95% CI, 1.24–4.43; p=0.009); fever, 3.22 (95% CI, 1.41–7.33; p=0.005), and night sweats, 3.78 (95% CI, 1.97–7.26; p<0.001). There was no relation between sperm quality and pre-treatment follicle stimulating hormone level.

Conclusions

In this large study of males with Hodgkin’s lymphoma, 90% had good or intermediate sperm quality. Three percent were azoospermic. There was an association between sperm quality and the presence or absence of B-symptoms, in particular fever and night sweats. With modern fertilization techniques, in most patients with early-stage Hodgkin’s lymphoma sperm quality before treatment is good enough for future fatherhood.     

Blanks, a nuclear siRNA/dsRNA-binding complex component, is required for Drosophila spermiogenesis

Small RNAs and a diverse array of protein partners control gene expression in eukaryotes through a variety of mechanisms. By combining siRNA affinity chromatography and mass spectrometry, we have identified the double-stranded RNA-binding domain protein Blanks to be an siRNA- and dsRNA-binding protein from Drosophila S2 cells. We find that Blanks is a nuclear factor that contributes to the efficiency of RNAi. Biochemical fractionation of a Blanks-containing complex shows that the Blanks complex is unlike previously described RNA-induced silencing complexes and associates with the DEAD-box helicase RM62, a protein previously implicated in RNA silencing. In flies, Blanks is highly expressed in testes tissues and is necessary for postmeiotic spermiogenesis, but loss of Blanks is not accompanied by detectable transposon derepression. Instead, genes related to innate immunity pathways are up-regulated in blanks mutant testes. These results reveal Blanks to be a unique component of a nuclear siRNA/dsRNA-binding complex that contributes to essential RNA silencing-related pathways in the male germ line.     

Resolving variation in the reproductive tradeoff between sperm size and number

Spermatozoa are amongst the most variable cells, and three factors are thought to account for this variation in design: fertilization mode, phylogeny, and postcopulatory sexual selection. In addition, it has long been assumed that a tradeoff exists between sperm size and number, and although postcopulatory sexual selection affects both traits, empirical evidence for a tradeoff has so far been elusive. Our recent theoretical model predicts that the nature of a direct tradeoff between sperm size and number varies with sperm competition mechanism and sperm competition risk. We test these predictions using a comparative approach in two very different taxa with different sperm competition mechanisms: passerine birds (mechanism: simple raffle) and Drosophila fruit flies (sperm displacement). We show that in both groups, males increase their total ejaculate investment with increasing sperm competition risk, but whereas passerine birds allocate disproportionately to sperm number, drosophilids allocate disproportionately to sperm size. This striking difference between the two groups can be at least partly explained by sperm competition mechanisms depending on sperm size relative to the size of the female reproductive tract: in large animals (passerines), sperm numbers are advantageous in sperm competition owing to dilution inside the female tract, whereas in small animals (drosophilids), large sperm are advantageous for physical competition (sperm displacement). Our study provides two important results. First, we provide convincing evidence for the existence of a sperm size-number tradeoff. Second, we show that by considering both sperm competition mechanism and dilution, can we account for variation in sperm size between different taxa.     

外源性睾酮对睾丸蛋白质组学的影响

目的观察外源性睾酮对睾丸蛋白质组学的影响。方法40例有生育能力的健康成年男性志愿者,随机分为观察组和对照组,各20例。观察组首次肌肉注射十一酸睾酮（TU）1000mg,第6、12周肌注TU500mg给药结束后第2周行睾丸穿刺取睾丸组织行免疫组化及蛋白质组学分析,利用生物信息学技术对蛋白质功能进行分析。结果与对照组相比观察组给药结束后第2周睾丸组织未见组织学变化,蛋白质组学研究结果显示观察组睾丸组织中有12个蛋白点表达与对照组相比P〈0．05,4个蛋白点被鉴定,分别为ACTB蛋白、CALB2蛋白、SOD2蛋白、PSMF1蛋白。结论外源性外源性睾酮可导致睾丸组织ACTB蛋白、CALB2蛋白、SOD2蛋白、PSMF1蛋白等12种蛋白表达变化,这可能是外源性睾酮抑制精子生成的机制之一。     

Physiological volume regulation by spermatozoa

Maturing spermatozoa passing through the epididymis experience increasing osmolality in the luminal environment and mature cells are stored in fluids hyper-osmotic to serum. When ejaculated into the female tract, they encounter a hypo-osmotic challenge which initiates the process of regulatory volume decrease (RVD). Defects in RVD result in hindrance of mucus penetration in man and failure of utero-tubal passage in mice. Epididymal sperm from the mouse and cynomolgus monkey and ejaculated sperm from man and monkey have been isolated and dispersed in media with osmolalities mimicking those of uterine fluid or cervical mucus. The effects of specific and broad-spectrum ion channel blockers indicate the involvement of separate K⁺ and Cl⁻ channels as well as organic osmolytes in physiological sperm RVD, with mechanisms developed during epididymal maturation. Western blotting and immuno-cytochemistry identify and localise some of these channels which play a crucial role in fertilisation in vivo and could be targets for post-testicular contraception.     

弓形虫感染与精子膜功能完整性的研究

目的　探讨弓形虫感染对精子膜功能的影响。方法　将 1 79例弓形虫检测的不育男性分为抗弓形虫抗体(ATAb)阳性组 (53例 )和阴性组 (1 2 6例 ) ,对其精液做低渗膨胀试验 ,进行对照分析。结果　ATAb阳性组的精子总膨胀率(44 50± 8 69)明显低于ATAb阴性组 (58 2 5± 9 48,P <0 0 1 ) ;ATAb阳性组 g型精子总膨胀率 (1 0 75± 3 2 2 )明显低于ATAb阴性组 (1 6 0 2± 6 2 8,P <0 0 1 )。结论　弓形虫感染对精子膜功能有明显影响 ,是弓形虫引起男性不育的原因之一     

日本血吸虫精子的超微结构

目的：了解日本血吸虫正常精子的超微结构。方法：半超薄切片定位雄虫睾丸和含有成熟精子的雌虫输卵管，常规透射电镜制样并观察。结果：日本血吸虫精子由头、尾两部分组成，头部呈长卵圆形，平均长6．2μm，宽1．4μm，无顶体构造，前端钝圆，后端尖细，质膜下有1圈纵行的微管，核1个，前端有少量线粒体，尾部鞭毛1根，在中、后段主体部分鞭毛轴丝外周为9组二联管，中央为一团弥散的电子致密物质，呈9×2＋《1》型；但在过渡区鞭毛轴丝中央无电子致密物质，呈9×2＋0型。结论：日本血吸虫精子超微结构与其他血吸虫相似，具有同源性，但明显区别于复殖目大多数吸虫的构造。