环境雌激素的男性生殖健康效应

概述了近年来国内外学者对内分泌干扰物健康效应的解释，及其对环境雌激素作用的新认识和男性生殖健康的影响。重点讨论了环境雌激素对男性生殖系统结构和功能的影响，以及造成男性生殖健康不良效应的可能作用机理及其最新研究进展，并简要介绍了对环境雌激素健康机制的进一步研究方向。根据报道，环境雌激素可以通过模拟天然雌激素的受体结合机制，干扰生物体内正常的内分泌生物机制，并使生殖系统的肿瘤发病率上升。     

典型酚类污染物内分泌干扰效应研究——对斑马鱼发育及核受体介导基因调控的分子影响

以斑马鱼为研究对象,观察2,4,6-三氯酚（2,4,6-trichlorophenol）、4-氯-3-甲酚（4-chloro-3-methylphenol）和4-硝基苯酚（4-nitrophenol）3种酚类污染物对斑马鱼胚胎发育早期阶段形态学指标的影响,借助q-RT-PCR方法对斑马鱼胚胎分别暴露于0.1,0.5和2.5mg/L至120hpf幼鱼8个重要受体（雄激素受体（AR）、甲状腺激素受体（TR）、芳香烃受体（AhR）、雌激素受体（ER）、糖皮质激素受体（GR）、孕烷X受体（PXR）、盐皮质激素受体（MR）、过氧化物酶体增殖物激活受体（PPAR））相关基因的转录水平进行了研究;进一步采用分子对接和分子动力学模拟的方法研究污染物与筛选出的影响受体（ER、AhR、PXR、GR以及MR）之间的相互作用过程.结果表明,在5和10mg/L的浓度下3种酚类污染物都显著影响斑马鱼的发育,造成脊柱弯曲、心包水肿等不良影响;基因结果显示2,4,6-三氯酚暴露导致ER的基因下调,雌激素受体α（er1）基因在2.5mg/L浓度下下调2.1倍.4-氯-3-甲酚显著影响ER、AhR以及PXR的相关基因,表现为在0.5和2.5mg/L暴露er1基因显著下调1.8和2.2倍,ahr2和pxr基因在0.1和2.5mg/L的浓度下分别下调1.7和1.8倍和上调3.5和3.2倍.4-硝基苯酚暴露使GR、MR核心受体基因发生调控变化,糖皮质激素受体基因（gr）在低中浓度下分别显著上调2.0和2.1倍,最高浓度下下调1.9倍.盐皮质激素受体基因（mr）在中高浓度下分别下调1.9和2.1倍,在最低浓度下显著上调1.7倍;分子计算结果显示它们与相关受体通过疏水和氢键等相互作用而稳定结合,且均方根偏差（RMSD）在5ns后稳定.这3个典型酚类污染物主要通过斑马鱼ER、AhR、PXR、GR、MR受体介导产生内分泌干扰效应并影响其早期生长发育.     

Parker��s sneak-guard model revisited: why do reproductively parasitic males heavily invest in testes?

Alternative reproductive tactics are widespread in males and may cause intraspecific differences in testes investment. Parker's sneak-guard model predicts that sneaker males, who mate under sperm competition risk, invest in testes relatively more than bourgeois conspecifics that have lower risk. Given that sneakers are much smaller than bourgeois males, sneakers may increase testes investment to overcome their limited sperm productivity because of their small body sizes. In this study, we examined the mechanism that mediates differential testes investment across tactics in the Lake Tanganyika cichlid fish Lamprologus callipterus. In the Rumonge population of Burundi, bourgeois males are small compared with those in other populations and have a body size close to sneaky dwarf males. Therefore, if differences in relative testis investment depend on sperm competition, the rank order of relative testis investment should be dwarf males?>?bourgeois males in Rumonge?=?bourgeois males in the other populations. If differences in relative testis investment depend on body size, the rank order of relative testes investment should be dwarf males?>?bourgeois males in Rumonge?>?bourgeois males in the other populations. Comparisons of relative testis investment among the three male groups supported the role of sperm competition, as predicted by the sneak-guard model. Nevertheless, the effects of absolute body size on testes investment should be considered to understand the mechanisms underlying intraspecific variation in testes investment caused by alternative reproductive tactics.     

Within-population variation in ejaculate characteristics in a prolonged breeder,Peron’s tree frog, <Emphasis Type="Italic">Litoria peronii</Emphasis>

Sperm number is often a good predictor of success in sperm competition; however, it has become increasingly clear that, for some species, variation in probability of paternity cannot be explained by sperm number alone. Intraspecific variation in ejaculate characteristics, such as the number of viable sperm and sperm longevity, may play an equally important role in determining fertilization success. Here, we assess variation among ejaculates in three factors that may contribute to fertilization success (number of sperm per ejaculate, viability, and longevity), in a population of Peron’s tree frog (Litoria peronii). We detected large variation among males in the number of sperm per ejaculate and the proportion of viable sperm within ejaculates, which could not be explained by variation in either male size or body condition. However, the proportion of viable sperm released by males increased over the season. Finally, we assessed sperm longevity (proportion viable sperm determined using a dual-fluorochrome vital dye) at two different temperatures. At 23°C, on average, 75% of sperm remained viable after 2 h, but there were significant differences amongst males with the percentage of viable sperm ranging from 43% to 95%. For sperm incubated at 4°C, ejaculates varied fivefold in sperm longevity with some males having 50% viable sperm after 5 days. Our data suggest that ejaculate characteristics (sperm number, viability, and longevity) vary widely in Peron’s tree frog and may therefore play an important role in determining siring success both in the presence and absence of sperm competition. We discuss the results in relation to selection on ejaculate traits via natural and sexual selection in this and other amphibians.     

Prenatal analysis of insulin receptor autophosphorylation in a family with leprechaunism

We describe a method for the isolation and functional characterization of insulin receptors from chorionic villi and cultured amniotic fluid cells. The functionality of these receptors is assayed by measuring the insulin-induced stimulation of autophosphorylation of the receptor β-chain. The method is expected to allow the prenatal diagnosis of those forms of lep-rechaunism and related diseases which are the result of a decreased stimulation by insulin of receptor autophosphorylation. A pregnancy at risk for leprechaunism was examined and an unaffected child was correctly predicted by study of the functionality of the insulin receptor on cultured amniocytes and by echoscopic examination.     

Zelluläre Wirkungen der ultravioletten Komponente des Sonnenlichts

The discussion on the possible increase of solar UV on earth due to the destruction of the stratospheric ozone has led to a renewed interest in the action of ultraviolet radiation on biological systems. The paper deals with changes at the cellular level stressing particularly molecular alterations in deoxyribonucleic acid, the carrier of genetic information. The most important repair processes by which lesions are removed or bypassed are described. It is also discussed whether the effectivity of a complex spectrum can be predicted on the basis of measurements with monochromatic radiation. Furthermore, possible consequences on human health are outlined which may be derived from cellular studies.     

Atmospheric emissions of some POPs in Europe: a discussion of existing inventories and data needs

Accurate and complete information on the emissions of persistent organic pollutants (POPs) are essential for interpreting historical, current and future contamination levels in remote areas. However, this information is also crucial for decision makers aiming at further reduction of the environmental loading of these substances on a regional scale. In this study, we identify and discuss specific POP emission inventory features that are deemed essential to understand, predict and control the behaviour of such substances on a European scale. It is shown that the scientific value of official emission data is limited (e.g. for deriving source–receptor relationships on a European scale), as there is insufficient information on spatial, temporal and compound coverage. Likewise, we argue that non-official emission data (i.e. research-driven emission inventories), which are based on aggregated statistics, may be of limited value for the identification of further emission control strategies. It is thus argued that future emission inventories should be developed in a format that is suitable to serve both policy- and research-oriented applications. Further improvement of official emission data with respect to research-driven features seems to be the most sensible way to proceed. Finally, the empirical basis of current emission inventories remains weak, and further research on emission identification and characterisation seem needed (a) to gain confidence in predicted source–receptor relationship as well as (b) for the development of sound control strategies.     

Copulatory behavior in a pholcid spider: males use specialized genitalic movements for sperm removal and copulatory courtship

Sexual selection may operate on pre-copulatory, copulatory, and post-copulatory traits. An example of a copulatory target of sexual selection is the genitalic movements a male performs during copulation. These movements may function either to prevent sperm competition or to influence a female’s fertilization decision. Here we investigated how copulation duration, pedipalp movements, and abdominal movements that males of the pholcid spider Holocnemus pluchei produce during copulation influence sperm removal and/or patterns of successful sperm transfer. We compared mating events with virgin and mated females for differences in copulatory and post-copulatory behavior. We expected longer copulation duration, longer pedipalp movement duration, and more complex and frequent pedipalp and abdominal movements when males mated with mated females compared to virgin females. Except for abdominal movements, our results corroborated these predictions. Furthermore, when we investigated mating events with mated females, we observed sperm mass ejection from the female gonopore and physical removal of sperm by males’ procursi. Females with interrupted second mating events showed a significant reduction of stored sperm masses compared to females with completed mating events. We suggest that males use alternating pedipalp movements to remove most of the rival sperm stored by mated females prior to sperm transfer. Copulation duration and pedipalp movements can be further used to transfer sperm and/or as a form of genitalic copulatory courtship.     

Sperm competition promotes diversity of sperm bundles in <Emphasis Type="Italic">Ohomopterus</Emphasis> ground beetles

Diversification of sperm morphology has been investigated in the context of sperm competition, but the adaptive significance of sperm bundles is still unclear. In analyzing 10 taxa of the genus Carabus subgenus Ohomopterus and one related Carabus ground beetles, we found that dimorphic sperm bundles occurred in most species with varied degrees of bimodality, whereas sperm were generally monomorphic. Comparative analyses with phylogenetically independent contrasts revealed that the sizes of large and small sperm bundles evolved more rapidly than, and were not correlated with, the length of sperm, suggesting more intense selection on sperm bundle sizes and their independent responses to different evolutionary forces. The size of large sperm bundles was positively correlated with male genital morphology (pertinent to displacement of rival spermatophores) and postcopulatory guarding duration as well as male body length, suggesting that larger sperm bundles have been favored when the risk of spermatophore displacement is high. Larger sperm bundles may be advantageous because of their ability to migrate more rapidly into the spermatheca. In contrast, no clear association was detected between the small sperm bundle size and mating traits despite its rapid diversification. The present study provides the first record of heteromorphic sperm bundles, the diversity of which may be promoted by sperm competition.     

Origin of Metazoa: Sponges as Living Fossils

Geodia cydonium  , which code for proteins. The analyses of their deduced amino acid sequences allowed a molecular biological approach to solve the problem of monophyly of Metazoa. Molecules of the extracellular matrix/basal lamina, with the integrin receptor, fibronectin, and galectin as prominent examples, cell-surface receptors (tyrosine kinase receptor), elements of sensory systems (crystallin, metabotropic glutamate receptor), and homologs/modules of an immune system (immunoglobulin like molecules, scavenger receptor cysteine-rich, and short consensus repeats, rhesus system) classify the Porifera as true Metazoa. As living fossils, provided with simple, primordial molecules allowing cell-cell and cell-matrix adhesion as well as processes of signal transduction as known in a more complex manner from higher Metazoa, they also show peculiarities not known in other metazoan phyla. Tissues of sponges are rich in telomerase activity, suggesting a high plasticity in the determination of cell lineages. It is concluded that molecular biological studies with sponges as model will not only help to understand the evolution of Protoctista to Metazoa but also the complex, hierarchial regulatory network of cells in higher Metazoa.     

No evidence for sperm priming responses under varying sperm competition risk or intensity in guppies

Sperm competition theory predicts that males should tailor their investment in ejaculates according to the number of rival males competing to fertilize a female’s eggs. Research spanning several taxa supports this prediction by showing that males are often sensitive to the level of sperm competition and adjust their investment in sperm numbers accordingly. More recent work has revealed that males may also tailor the quality of sperm according to the number of males competing for fertilization. Here I test for both effects in guppies (Poecilia reticulata) in an experiment that simultaneously evaluates the risk and intensity models of sperm competition. The experiment determined whether male guppies adjust the number (stripped ejaculate size) and quality (sperm velocity and viability) of sperm that are primed over a 3-day period according to experimental changes in the perceived level of sperm competition. A total of 136 focal males were initially stripped of all retrievable sperm and assayed for these sperm traits before being allocated at random to one of four treatments simulating different levels of sperm competition risk and intensity. During the 3-day treatment phase, focal males had visual and olfactory access to a sexually receptive (initially virgin) female maintained with different numbers of stimulus males to simulate variation in the risk and intensity of sperm competition. Following this, males were assayed again for the sperm traits. Contrary to predictions, there was no significant change in any of the measured variables among treatments, although qualitatively the patterns for sperm velocity and viability did conform to expectation. The lack of any trend for the number of sperm primed was unequivocal and future work examining the effects of sperm competition on sperm production should focus on whether males differentially allocate sperm numbers among matings that differ in the level of sperm competition.     

Spectral heterogeneity of honeybee ommatidia

The honeybee compound eye is equipped with ultraviolet, blue, and green receptors, which form the physiological basis of a trichromatic color vision system. We studied the distribution of the spectral receptors by localizing the three mRNAs encoding the opsins of the ultraviolet-, blue- and green-absorbing visual pigments. The expression patterns of the three opsin mRNAs demonstrated that three distinct types ommatidia exist, refuting the common assumption that the ommatidia composing the bee compound eye contain identical sets of spectral receptors. We found that type I ommatidia contain one ultraviolet and one blue receptor, type II ommatidia contain two ultraviolet receptors, and type III ommatidia have two blue receptors. All the three ommatidial types contain six green receptors. The ommatidia appear to be distributed rather randomly over the retina. The ratio of type I, II, and III ommatidia was about 44:46:10. Type III ommatidia appeared to be slightly more frequent (18%) in the anterior part of the ventral region of the eye. Retinal heterogeneity and ommatidial randomness, first clearly demonstrated in butterflies, seems to be a common design principle of the eyes of insects.     

Ovarian fluid of receptive females enhances sperm velocity

The females of several internal fertilizers are able to store sperm for a long time, reducing the risk of sperm limitation. However, it also means that males can attempt to mate outside females’ receptive period, potentially increasing the level of sperm competition and exacerbating sexual conflict over mating. The guppy (Poecilia reticulata), an internally fertilizing fish, is a model system of such competition and conflict. Female guppies accept courtship and mate consensually only during receptive periods of the ovarian cycle but receive approximately one (mostly forced) mating attempt per minute both during and outside their sexually receptive phase. In addition, females can store viable sperm for months. We expected that guppy females would disfavour sperm received during their unreceptive period, possibly by modulating the quality and/or quantity of the components present in the ovarian fluid (OF) over the breeding cycle. Ovarian fluid has been shown to affect sperm velocity, a determinant of sperm competition success in this and other fishes. We found that in vitro sperm velocity is slower in OF collected from unreceptive females than in OF from receptive females. Visual stimulation with a potential partner prior to collection did not significantly affect in vitro sperm velocity. These results suggest that sperm received by unreceptive females may be disfavoured as sperm velocity likely affects the migration process and the number of sperm that reach storage sites.     

采用DNA条形码技术对厦门海域鱼卵、仔稚鱼种类的鉴定

以厦门海域采集到的鱼卵、仔稚鱼为研究对象.首先根据形态学特征将其分为2种类型鱼卵和3种类型仔稚鱼,然后应用DNA条形码技术分析鉴定得到3个鱼卵种类和4个仔稚鱼种类.其中,6种鉴定到种的水平,分别为汉氏棱鳀(Thryssa hamiltonii)鱼卵、颈带鲾(Nuchequula nuchalis)鱼卵、纹缟鰕虎鱼(Tridentiger trigonocephalus)仔鱼、髭缟鰕虎鱼(Tridentiger barbatus)仔鱼、斑鰶(Konosirus punctatus)仔鱼和鲬(Platycephalus indicus)稚鱼;1种鉴定到属,即双边鱼属(Ambassis sp.)鱼卵.研究结果表明,将鱼卵、仔稚鱼鉴定到种的水平,绝大多数都需要借助于形态学之外的手段,尤其是形态特征表现相近的鱼卵.而DNA条形码技术采用自动化和标准化应用系统,能有效地对形态特征相似的鱼卵、仔稚鱼进行种类鉴定,具有准确性高、重复性好、人为误差少等优点,已成为传统形态学物种鉴定的强有力补充,在鱼类生物多样性研究中具有广阔的应用前景.     

Ultrastructure of spermatozoa of <Emphasis Type="Italic">Onthophagus taurus</Emphasis> (Coleoptera,Scarabaeidae) exhibits heritable variation

Sperm competition is thought to be an important selective pressure shaping sperm form and function. However, few studies have moved beyond gross examinations of sperm morphology. Sperm length is subject to sexual selection via sperm competition in the scarab beetle Onthophagus taurus. Here, the structure and ultrastructure of spermatozoa in this species were investigated using light and electron microscopy. Spermatozoa were found to be filiform, measuring about 1,200 mm in length. The sperm head consists of a three-layered acrosome and a nuclear region bearing the anterior extension of the centriole adjunct. Acrosome and nuclear regions are bilaterally symmetric, with their axes of symmetry being orthogonal to each other. Head and flagellar structures are connected by a well-developed centriole adjunct. The sperm heads are asymmetrically surrounded by accessory material and embedded into the cytoplasm of the spermatocyst cell. The accessory material is produced inside the spermatids and then transferred to the outside due to a new membrane formed around the sperm’s organelles. The old spermatid membrane separates the accessory material from the cyst cell. The flagellum contains a 9+9+2 axoneme, two accessory bodies, and two mitochondrial derivatives of unequal size. The major mitochondrial derivative is significantly larger than the minor one. The axoneme is arranged in a sinusoidal manner parallel along the major mitochondrial derivative. The spermatozoa show no progressive motility when released in buffer solution which is likely to be the result of the flagellar arrangement and the structure of the major mitochondrial derivative. The cross-sectional area of the minor and the major mitochondrial derivatives show different patterns of genetic variation. The data provide the first estimates of genetic variation in sperm ultrastructure for any species, and give evidence for the persistence of genetic variation in ultrastructure required for the rapid and divergent evolution that characterizes spermatozoa generally.     

Body size phenotypes are heritable and mediate fecundity but not fitness in the lepidopteran frugivore Cydia pomonella

The inheritance and functional roles of quantitative traits are central concerns of evolutionary ecology. We report two sets of experiments that investigated the heritability and reproductive consequences of body size phenotypes in a globally distributed lepidopteran frugivore, Cydia pomonella (L.). In our first set of experiments, we tested the hypotheses that (1) body size is heritable and (2) parental body size mediates egg production and offspring survival. Midparent–offspring regression analyses revealed that body mass is highly heritable for females and moderately heritable for males. The contribution of fathers to estimates of additive genetic variance was slightly greater than for mothers. Egg production increased with mean parental size, but offspring survival rates were equivalent. Based on this result, we tested two additional hypotheses in a second set of experiments: (3) male size moderates female egg production and egg fertility and (4) egg production, egg fertility, and offspring survival rate are influenced by female mating opportunities. Females paired with large males produced more eggs and a higher proportion of fertile eggs than females paired with small males. Females with multiple mating opportunities produced more fertile eggs than females paired with a single male. However, egg production and offspring survival rates were unaffected by the number of mating opportunities. Our experiments demonstrate that body mass is heritable in C. pomonella and that size phenotypes may mediate fecundity but not fitness. We conclude that male size can influence egg production and fertility, but female mate choice also plays a role in determining egg fertility.     

Sperm bundle and reproductive organs of carabid beetles tribe Pterostichini (Coleoptera: Carabidae)

The morphological characteristics of sperm and reproductive organs may offer clues as to how reproductive systems have evolved. In this paper, the morphologies of the sperm and male reproductive organs of carabid beetles in the tribe Pterostichini (Coleoptera: Carabidae) are described, and the morphological associations among characters are examined. All species form sperm bundles in which the head of the sperm was embedded in a rod-shaped structure, i.e., spermatodesm. The spermatodesm shape (left-handed spiral, right-handed spiral, or without conspicuous spiral structure) and the condition of the sperm on the spermatodesm surface (with the tail free-moving or forming a thin, sheetlike structure) vary among species. In all species, the spiral directions of the convoluted seminal vesicles and vasa deferentia are the same on both sides of the body; that is, they show an asymmetric structure. The species in which the sperm bundle and the seminal vesicles both have a spiral structure could be classified into two types, with significant differences in sperm-bundle length between the two types. The species with a sperm-bundle spiral and seminal-vesicle spiral of almost the same diameter have longer sperm bundles than the species with a sperm-bundle spiral and seminal-vesicle tube of almost the same diameter. In the former type, the spiral directions of the sperm bundles and seminal vesicles are inevitably the same, whereas they differ in some species with the later type. Therefore, increased sperm bundle length appears to have been facilitated by the concordance of the sperm bundle’s coiling direction with the coiling direction of the seminal vesicle.     

Modification of Glutamate Receptor Channels: Molecular Mechanisms and Functional Consequences

N  -methyl-d-aspartate (NMDA) types] by phosphorylation and changes in subunit composition. AMPA- and kainate-activated receptors are modulated by adenosine 3, 5-monophosphate (cAMP) dependent protein kinase A (PKA) coupled via D₁ dopamine receptors. An increase in the intracellular concentration of cAMP and protein kinase A potentiates kainate-activated currents in α-motoneurons of the spinal cord by increasing the affinity of the ligand (glutamate) for the phosphorylated receptor protein (GluR6 and 7). The rapid desensitization of AMPA-evoked currents normally observed in horizontal cells of the retina is completely blocked by increasing the intracellular concentration of cAMP. The effects of changes in subunit composition were examined in rat hippocampal neurons. The subunit composition of the NMDA receptor determines the kinetic properties of synaptic currents and can be regulated by the type of innervating neuron. Similar changes also occur during development. An important determinant here is the activity of the system. Dynamic regulation of excitatory receptors by both mechanisms may well be associated with some forms of learning and memory in the mammalian brain.