Complementarity between sperm surface beta-1,4-galactosyltransferase and egg-coat ZP3 mediates sperm-egg binding.

Despite its importance, the molecular basis of mammalian gamete recognition has remained unclear. The enzyme beta-1,4-galactosyltransferase (Gal-transferase) has been viewed traditionally as a biosynthetic component of the Golgi complex, but is also found on the surface of many cells where it can bind its specific glycoside substrate on adjacent cell surfaces or in the extracellular matrix. In mouse it has been suggested that Gal-transferase on the sperm head mediates fertilization by binding oligosaccharide residues in the egg coat, or zona pellucida, and that the ability of the zona pellucida to bind sperm is conferred by oligosaccharides of the ZP3 glycoprotein. However, it has not been confirmed that Gal-transferase and ZP3 are in fact complementary gamete receptors whose interaction mediates sperm-egg binding. Here we show that mouse sperm Gal-transferase specifically recognizes those oligosaccharides on ZP3 that have sperm-binding activity, but does not interact with other zona pellucida glycoproteins. In contrast, all zona pellucida glycoproteins are recognized by non-sperm Gal-transferase, demonstrating a more stringent substrate specificity for the sperm enzyme. This interaction is required for sperm-egg binding because blocking or removing the binding site for Gal-transferase on ZP3 inhibits its ability to bind sperm. After the release of the sperm acrosome, the transferase relocalizes to a new membrane domain where it can no longer bind to ZP3, which is consistent with the inability of acrosome-reacted sperm to bind ZP3 or to initiate binding to the zona pellucida. Following fertilization, ZP3 is modified by egg cortical granule secretions so that it loses sperm receptor activity, which can be accounted for by a selective loss of its binding site for sperm Gal-transferase. These results show that sperm surface beta-1,4-galactosyltransferase and the egg-coat glycoprotein ZP3 are complementary adhesion molecules that mediate primary gamete binding in the mouse.     

应用免疫印渍法检测猪和鱼卵透明带抗原的免疫交叉反应性

为了研究猪和鱼卵透明带抗原的免疫交叉反应性，应用免疫印渍术对其抗原组分进行了检测．实验结果表明，鱼卵透明带抗原与已知具有精子受体活性的猪ＺＰ３抗原，甚至猪全ＺＰ抗原均没有交叉反应．提示鱼卵透明带不含有与猪和人等哺乳类的透明带免疫学相类似的抗原决定簇．     

Sophisticated sperm allocation in male fowl

When a female is sexually promiscuous, the ejaculates of different males compete for the fertilization of her eggs; the more sperm a male inseminates into a female, the more likely he is to fertilize her eggs. Because sperm production is limited and costly, theory predicts that males will strategically allocate sperm (1) according to female promiscuity, (2) saving some for copulations with new females, and (3) to females producing more and/or better offspring. Whether males allocate sperm in all of these ways is not known, particularly in birds where the collection of natural ejaculates only recently became possible. Here we demonstrate male sperm allocation of unprecedented sophistication in the fowl Gallus gallus. Males show status-dependent sperm investment in females according to the level of female promiscuity; they progressively reduce sperm investment in a particular female but, on encountering a new female, instantaneously increase their sperm investment; and they preferentially allocate sperm to females with large sexual ornaments signalling superior maternal investment. Our results indicate that female promiscuity leads to the evolution of sophisticated male sexual behaviour.     

Female feral fowl eject sperm of subdominant males

Paternity is often determined by competition between the ejaculates of different males. Males can also use particular behaviours or structures to manipulate how females use sperm. However, the ability of females to bias sperm utilization in favour of preferred males independently of male manipulation has not been demonstrated. Females are predicted to respond differentially to the sperm of different males when the reproductive interests of the sexes differ and when females are coerced into copulating. Here we show that in female feral fowl most copulations are coerced, and that females consistently bias sperm retention in favour of the preferred male phenotype. Females prefer to copulate with dominant males, but when sexually coerced by subordinate males, they manipulate the behaviour of dominant males to reduce the likelihood of insemination. If this fails, females differentially eject ejaculates according to male status in the absence of any male manipulation and preferentially retain the sperm of dominant males.     

Sperm death and dumping in Drosophila

Mating with more than one male is the norm for females of many species. In addition to generating competition between the ejaculates of different males, multiple mating may allow females to bias sperm use. In Drosophila melanogaster, the last male to inseminate a female sires approximately 80% of subsequent progeny. Both sperm displacement, where resident sperm are removed from storage by the incoming ejaculate of the copulating male, and sperm incapacitation, where incoming seminal fluids supposedly interfere with resident sperm, have been implicated in this pattern of sperm use. But the idea of incapacitation is problematic because there are no known mechanisms by which an individual could damage rival sperm and not their own. Females also influence the process of sperm use, but exactly how is unclear. Here we show that seminal fluids do not kill rival sperm and that any 'incapacitation' is probably due to sperm ageing during sperm storage. We also show that females release stored sperm from the reproductive tract (sperm dumping) after copulation with a second male and that this requires neither incoming sperm nor seminal fluids. Instead, males may cause stored sperm to be dumped or females may differentially eject sperm from the previous mating.     

The immunoglobulin superfamily protein Izumo is required for sperm to fuse with eggs

Representing the 60 trillion cells that build a human body, a sperm and an egg meet, recognize each other, and fuse to form a new generation of life. The factors involved in this important membrane fusion event, fertilization, have been sought for a long time. Recently, CD9 on the egg membrane was found to be essential for fusion, but sperm-related fusion factors remain unknown. Here, by using a fusion-inhibiting monoclonal antibody and gene cloning, we identify a mouse sperm fusion-related antigen and show that the antigen is a novel immunoglobulin superfamily protein. We have termed the gene Izumo and produced a gene-disrupted mouse line. Izumo-/- mice were healthy but males were sterile. They produced normal-looking sperm that bound to and penetrated the zona pellucida but were incapable of fusing with eggs. Human sperm also contain Izumo and addition of the antibody against human Izumo left the sperm unable to fuse with zona-free hamster eggs.     

A potential fusion peptide and an integrin ligand domain in a protein active in sperm-egg fusion.

The union of sperm and egg is a special membrane fusion event that gives a signal to begin development. We have hypothesized that proteins mediating cell-cell fusion events resemble viral fusion proteins and have shown that PH-30, a sperm surface protein involved in sperm-egg fusion, shares biochemical characteristics with viral fusion proteins. We report here the complementary DNA and deduced amino-acid sequences of the mature alpha and beta subunits of PH-30. Both are type-I integral membrane glycoproteins. The alpha subunit contains a putative fusion peptide typical of viral fusion proteins and the beta subunit contains a domain related to a family of soluble integrin ligands found in snake venoms. Thus, the PH-30 alpha/beta complex resembles many viral fusion proteins in both its membrane topology and its predicted binding and fusion functions.     

Outbred embryos rescue inbred half-siblings in mixed-paternity broods of live-bearing females

Females commonly mate with more than one male, and polyandry has been shown to increase reproductive success in many species. Insemination by multiple males shifts the arena for sexual selection from the external environment to the female reproductive tract, where sperm competition or female choice of sperm could bias fertilization against sperm from genetically inferior or genetically incompatible males. Evidence that polyandry can be a strategy for avoiding incompatibility comes from studies showing that inbreeding cost is reduced in some egg-laying species by postcopulatory mechanisms that favour fertilization by sperm from unrelated males. In viviparous (live-bearing) species, inbreeding not only reduces offspring genetic quality but might also disrupt feto-maternal interactions that are crucial for normal embryonic development. Here we show that polyandry in viviparous pseudoscorpions reduces inbreeding cost not through paternity-biasing mechanisms favouring outbred offspring, but rather because outbred embryos exert a rescuing effect on inbred half-siblings in mixed-paternity broods. The benefits of polyandry may thus be more complex for live-bearing females than for females that lay eggs.     

Sperm competition between Drosophila males involves both displacement and incapacitation.

Females in almost all animal groups copulate with multiple males. This behaviour allows different males to compete for fertilization and gives females the opportunity to mediate this competition. In many animals and most insects, the second male to copulate with a female typically sires most of her offspring. In Drosophila melanogaster, this second-male sperm precedence has long been studied but, as in most species, its mechanism has remained unknown. Here we show, using labelled sperm in doubly mated females, that males can both physically displace and incapacitate stored sperm from earlier-mating males. Displacement occurs only if the second male transfers sperm to the female, and in only one of her three sperm-storage organs. Incapacitation can be caused by either fertile or spermless second males, but requires extended intervals between matings. Sperm from different males are not 'stratified' in the storage organs but mix freely. Many animal species may have multiple mechanisms of sperm competition like those observed here, and revealing these mechanisms is necessary to understand the genetic and evolutionary basis of second-male sperm precedence in animals.     

Male mammals respond to a risk of sperm competition conveyed by odours of conspecific males

Sperm competition occurs when a female copulates with two or more males and the sperm of those males compete within the female's reproductive tract to fertilize her eggs. The frequent occurrence of sperm competition has forced males of many species to develop different strategies to overcome the sperm of competing males. A prevalent strategy is for males to increase their sperm investment (total number of sperm allocated by a male to a particular female) after detecting a risk of sperm competition. It has been shown that the proportion of sperm that one male contributes to the sperm pool of a female is correlated with the proportion of offspring sired by that male. Therefore, by increasing his sperm investment a male may bias a potential sperm competition in his favour. Here we show that male meadow voles, Microtus pennsylvanicus, increase their sperm investment when they mate in the presence of another male's odours. Such an increase in sperm investment does not occur by augmenting the frequency of ejaculations, but by increasing the amount of sperm in a similar number of ejaculations.     

Directional postcopulatory sexual selection revealed by artificial insemination

Postcopulatory sexual selection comprises both sperm competition, where the sperm from different males compete for fertilization, and cryptic female choice, where females bias sperm use in favour of particular males. Despite intense current interest in both processes as potential agents of directional sexual selection, few studies have attributed the success of attractive males to events that occur exclusively after insemination. This is because the interactions between pre- and post-insemination episodes of sexual selection can be important sources of variation in paternity. The use of artificial insemination overcomes this difficulty because it controls for variation in male fertilization success attributable to the female's perception of male quality, as well as effects due to mating order and the relative contribution of sperm from competing males. Here, we adopt this technique and show that in guppies, when equal numbers of sperm from two males compete for fertilization, relatively colourful individuals achieve greater parentage than their less ornamented counterparts. This finding indicates that precopulatory female mating preferences can be reinforced exclusively through postcopulatory processes occurring at a physiological level. Our analysis also revealed that relatively small individuals were advantaged in sperm competition, suggesting a possible trade-off between sperm competitive ability and body growth.     

怒族成人Heath-Carter法体型研究

运用Heath-Carter人体测量体型方法对云南省怒江州的贡山县丙中洛乡和福贡县匹河乡怒族成年人317倒（男为183例，女为134倒）进行了体型评定．结果表明：（1）怒族成人平均体型男性为均衡的中胚层体型（2．1—4．9—2．6），女性为内胚层-中胚层均衡体型（4．3—4．5-1.7）．（2）随着年龄增长，怒族男女在20-岁组到40-岁组体型均呈内因子值增大、外因子值减小的趋势；50岁以后内因子值减小，外因子值增大；中因子值，男性在50岁前增大，50岁后减小，女性则一直增大．（3）男女问体型存在极显著性差异，女性中因子值、外因子值低于男性，而内因子值高于男性．（4）与其他群体相比，怒族内因子值偏低，中因子值偏高，外因子值偏高或居中，与侗族体型最接近（男性SAD=0．46；女性SAD=0．36），与布依族和仡佬族较为接近．     

Reduced vas deferens contraction and male infertility in mice lacking P2X1 receptors

P2X1 receptors for ATP are ligand-gated cation channels, present on many excitable cells including vas deferens smooth muscle cells. A substantial component of the contractile response of the vas deferens to sympathetic nerve stimulation, which propels sperm into the ejaculate, is mediated through P2X receptors. Here we show that male fertility is reduced by approximately 90% in mice with a targeted deletion of the P2X1 receptor gene. Male mice copulate normally--reduced fertility results from a reduction of sperm in the ejaculate and not from sperm dysfunction. Female mice and heterozygote mice are unaffected. In P2X1-receptor-deficient mice, contraction of the vas deferens to sympathetic nerve stimulation is reduced by up to 60% and responses to P2X receptor agonists are abolished. These results show that P2X1 receptors are essential for normal male reproductive function and suggest that the development of selective P2X1 receptor antagonists may provide an effective non-hormonal male contraceptive pill. Also, agents that potentiate the actions of ATP at P2X1 receptors may be useful in the treatment of male infertility.     

Hartley豚鼠SPF级核心种群生长曲线与血液生理生化指标测定

目的 测定SPF级Hartley豚鼠核心群的生长体质量,血液生理、生化指标,并与清洁级豚鼠各指标进行比较。方法 选择种群中雌、雄个体各10只,通过称重,记录0～8周龄体质量;豚鼠采血,应用全自动血细胞计数仪与全自动血液生化分析仪检测各项生理、生化指标。结果 在SPF级豚鼠血液生理指标中,白细胞计数(WBC)、中性粒细胞计数(NEUT)、嗜酸性粒细胞计数(EOS) 3项指标,在雌性与雄性间有显著性差异(P0. 05)外,其他指标均存在极显著差异(P<0. 01)。结论 绘制了SPF级豚鼠生长曲线。SPF级豚鼠血液学指标在性别间有差异,与清洁级豚鼠相比存在显著差异。     

动物卵母细胞透明带与受精的关系

阐述对哺乳动物卵母细胞透明带（ZP）在卵母细胞受精过程中的作用,指出卵母细胞ZP厚度、弹性、显微结构及理化结构是影响卵子受精过程的重要因素。     

SPF级与普通级Hartley豚鼠主要脏器系数的比较

目的测定SPF级和普通级Hartley豚鼠的主要脏器质量,比较屏障环境和普通环境下豚鼠脏器系数的差异。方法取2月龄SPF级和普通级豚鼠雌雄各30只,剖检取心、肝、脾、肺、肾等13个脏器,称其质量并计算脏器系数。结果SPF级和普通级Hartley豚鼠雌性之间比较,体质量、心、脾、肺、肾、肾上腺、子宫质量差异极显著（P〈0．01）;SPF级和普通级Hartley豚鼠雄性之间比较,心、肝、脾、肺、肾、肾上腺、胸腺、睾丸、附睾等其质量差异极显著（P〈0．01）。SPF级和普通级Hartley豚鼠雌性之间比较,心、脾、肺、肾、肾上腺、子宫的脏器系数差异极显著（P〈0．01）。SPF级和普通级Hartley豚鼠雄性之间比较,心、肝、脾、肺、肾、肾上腺、胸腺、睾丸、附睾的脏器系数差异极显著（P〈0．01）。结论SPF级和普通级Hartley豚鼠比,除脑以外的脏器系数均有显著差异,且普通级豚鼠的脏器系数普遍高于SPF级豚鼠。     

蝶豆花提取物的抗氧化活性及其对酮康唑诱导大鼠睾丸损伤的保护作用

研究目的：研究蝶豆花提取物的抗氧化活性及其对酮康唑（KET）诱导雄性大鼠睾丸损伤的保护作用。创新要点：对蝶豆花提取物保护酮康唑引起的雄性动物睾丸损伤进行研究，为减轻抗真菌药物酮康唑的生殖毒性提供理论依据和解决途径。研究方法：采用2,2-二苯基-1-苦肼基自由基（DPPH）分析法和亚铁还原能力实验法（FRAP）来测定蝶豆花提取物的抗氧化活性。在为期28天的动物试验中，前21天为预防期，第21至28天为KET诱导期。整个试验期中，对雄性大鼠进行蝶豆花提取物（0、50、100mg／kgBW）灌胃饲养；在诱导期，同时腹腔注射KET（100mg/kg BW）。试验结束后，测定睾丸、附睾和输精管以及精囊的重量、血清睾酮水平、精子浓度、组织结构、睾丸的直径和睾丸酪氨酸磷酸化水平。重要结论：蝶豆花提取物具有清除DPPH自由基能力和较高的还原能力，其在100mg／kg BW下对雄性大鼠生殖系统无毒。50、100mg/kg BW蝶豆花提取物能改善KET引起的生殖器官重量下降、血清睾酮水平和精子浓度，降低KET引起的睾丸损伤。与其他组相比，100mg／kg BW蝶豆花提取物能显著提高睾丸中50-kDa的酪氨酸磷酸化蛋白的表达。由此可见，具有抗氧化活性的蝶豆花提取物不会损伤雄性生殖系统，而且具有保护KET诱导大鼠睾丸损伤的作用。     

Variable female preferences drive complex male displays

Complexity in male sexual displays is widely appreciated but diversity in female mate choice has received little attention. Males of many species have sexual displays composed of multiple display traits, and females are thought to use these different traits in mate choice. Models of multiple display trait evolution suggest that these traits provide females with different kinds of information in different stages of the mate choice process, or function as redundant signals to improve the accuracy of mate assessment. We suggest that complex male displays might also arise because of variation in female preferences for particular male display traits. The causes of female preference variation have received little attention, and the role of preference variation in shaping complex male displays is unclear. Here we show that in satin bowerbirds (Ptilonorhynchus violaceus) female mate choice is a multistage process, where females of different ages use different male display traits in successive stages. Age- and stage-specific female preferences may contribute to explaining the widespread occurrence of multifaceted male displays.     

Transient activation of calcineurin is essential to initiate embryonic development in Xenopus laevis

At fertilization, an increase of cytosolic calcium ions (Ca2+) triggers various activation responses in animal eggs. In vertebrates, these responses include exit from metaphase arrest in meiosis II (MII exit) and cortical remodelling initiated by cortical granule exocytosis. Although the essential requirement of Ca2+/calmodulin-dependent protein kinase II for inducing MII exit has been documented, a role of the Ca2+/calmodulin-dependent protein phosphatase calcineurin in egg activation has not been investigated. Here we show, using cell-free extracts from unfertilized eggs of Xenopus laevis, that calcineurin is transiently activated immediately after Ca2+ addition to a concentration that induces MII exit. When calcineurin activation is inhibited, cyclin-dependent kinase 1 (Cdk1) inactivation by means of cyclin B degradation is prevented and sperm chromatin incubated in the extracts remains condensed. Similarly, if calcineurin is inhibited in intact eggs, MII exit on egg activation is prevented. In addition, the activation contraction in the cortex is suppressed whereas cortical granule exocytosis occurs. We further demonstrate that, when a high level of calcineurin activity is maintained after activation, growth of sperm asters is prevented in egg extracts and, consistently, migration of male and female pronuclei towards each other is hindered in fertilized eggs. Thus, both activation and the subsequent inactivation of calcineurin in fertilized eggs are crucial for the commencement of vertebrate embryonic development.     

大袋蛾雌成虫内部生殖系统的形态学和组织学

描述了大袋蛾（ＣｌａｎｉａｖａｒｉｅｇａｔａＳｎｅｌｌｅｎ）雌成虫内部生殖系统的形态学和组织学。大袋蛾雌成虫内部生殖器官与其它较高等的鳞翅目昆虫相比明显不同：交配囊极度退化，前庭中出现两个瓣膜。试验表明交尾后雌虫体内无精包，而在雌虫受精囊中发现精子束。这说明精子束被直接传输到受精囊中。大袋蛾是鳞翅目中发现的首例．交尾时不产生精包而直接授精的虫种。