环境雌激素生态影响的研究进展

环境雌激素(ｅｃｏｅｓｔｒｏｇｅｎ) ,是指能够扰乱动物内分泌活动 ,生理活性与雌激素较为相似的动物体外化学物质 ,包括人工合成化合物以及植物天然雌激素 ,由于目前所发现的干扰动物及人体内分泌系统的有机化合物绝大多数都具有激素特征 ,因此通常又将环境激素称做“干扰内分泌化合物”(ｅｎｄｏｃｒｉｎｅｄｉｓｒｕｐｔｉｎｇｃｈｅｍｉ ｃａｌｓ或ｅｎｄｏｃｒｉｎｅｄｉｓｒｕｐｔｅｒｓ)。环境激素问题只是在最近几年才引起世界关注 ,但由于环境激素污染范围广、影响大 ,对人类生存的威胁更直接 ,目前 ,西方国家将环境激素问题与臭…     

环境雌激素双酚A的研究进展

环境荷尔蒙是现代生命科学领域研究的热点之一,如今越来越多的人开始关注这一话题。在我们的生活环境中充斥着各种化学有毒试剂,其中,有一类物质能够模拟或抑制内分泌激素的活动,我们称之为内分泌干扰物。内分泌干扰物有能力改变内分泌系统的结构和功能。双酚A作为一种环境雌激素,属于内分泌干扰物的一种。双酚A被广泛应用于聚碳酸酯塑料和环氧树脂的制造。双酚A具有弱雌激素效应,能够与雌激素受体结合,引起内分泌系统的应答。目前的研究表明,双酚A会透过血胎屏障影响到胚胎发育,会对神经内分泌系统、肝组织功能以及生殖器的发育造成损伤。本文主要综述了环境雌激素双酚A在小鼠发育阶段所引起的诸多不利影响,并对环境荷尔蒙未来的研究方向进行了展望。     

铅对雄性生殖毒性的研究进展

从铅对睾丸与附睾形态、精子生成和发育以及生殖内分泌功能等三方面的影响综述了铅对雄性生殖毒性的研究进展;并从铅对睾丸的脂质过氧化损伤,对睾丸标志酶活性的影响,对染色体、DNA及基因的影响以及对CaM、Ca2 -ATP酶活性的影响等方面探讨了铅对雄性生殖毒性作用机理。同时,提出了铅对雄性生殖毒性的研究中存在的若干问题和发展方向。     

植物无融合生殖的遗传机理和分子机理的研究进展

利用植物无融合生殖固定杂种优势,已被认为是一条生产杂交种子的高效途径。近年来,由于RAPD、RFLP和差异显示等技术的应用,已使植物无融合生殖的研究面貌一新。特别是一系列与无融合生殖有关的特异DNA片段的发现,为深入了解其遗传机理和分子机理增加了大量新的知识,这些知识无疑为定位和克隆植物无融合生殖基因,进而利用遗传操作的手段来改变植物的生殖方式积累了必要的理论基础。本文对植物无融合生殖遗传机理和分子机理的研究进展作了综述。 Abstract:Apomixis allows the establishment of genetically stable seed propagating clones of crops,which can perpetuate themselves across countless sporophytic generations.This asexual mode of reproduction,which naturally occurs in some angiosperms,may prove to be an unrivalled tool to improve crop yields.The current state of knowledge on the molecular and genetic basis of apomixis is reviewed.     

环境雌激素的微生物代谢

环境雌激素作为一类重要的新型环境污染物,可通过干扰生物体的内分泌系统危害生物体健康。微生物降解是去除环境雌激素与进行环境修复的主要手段。本文归纳整理了目前研究较深入的雌激素降解微生物,类比阐述了其预测的降解通路与降解机制,并对后续环境雌激素降解研究的主要内容与方向进行了展望。     

环境内分泌干扰物对生殖健康影响的研究进展

环境内分泌干扰物(environmental endocrine disruptors,EEDs)是指环境中天然存在或污染的能够干扰机体内自然激素的合成、分泌、转运、结合、作用和消除等过程,表现出拟自然激素或抗自然激素的生理学作用的一类化合物。它们与人们的生活密不可分,比如邻苯二甲酸酯类(PAEs)和双酚A(BPA),就广泛存在于食品包装、儿童玩具及生活用品中。大量实验证据以及流行病学的调查表明环境内分泌干扰物对动物雌激素、睾酮、甲状腺素、儿茶酚胺等呈现显著的干扰效应,是生殖障碍、出生缺陷、发育异常、代谢紊乱以及某些恶性肿瘤的发病率增加的原因之一。本文归纳了环境内分泌干扰物(EEDs)对生殖健康影响的研究进展。     

雌激素β受体研究进展

雌激素是由芳香化酶催化雄激素转化而来的。脑组织局部产生的雌激素不仅作用于生殖系统,也深刻影响着脑发育、学习记忆和认知等功能。雌激素的信号是由雌激素受体介导的,以前只发现了一种雌激素受体,这面临着许多无法解释的现象,新克隆的雌激素受体即β受体加深了人们对雌激素信号途径的认识,为全面阐明雌激素在不同组织中的作用机制提供了新的线索。     

环境内分泌干扰物雌激素的微生物降解研究进展

雌激素是一类重要的环境内分泌干扰物。微生物降解是一种去除环境雌激素与进行环境修复的最绿色、环保、经济的方法。本文从分析雌激素的主要来源和危害、归纳国内外已报道的雌激素降解菌、总结雌激素降解的相关基因和组学研究进展、阐述雌激素的降解通路和降解机制这4个方面,概括阐述了环境雌激素的微生物降解作用,并对未来雌激素降解研究的主要内容与方向提出展望。     

三氯杀螨醇对大型溞的毒性和环境雌激素效应

三氯杀螨醇是DDT被禁用以后出现的替代品,在很多国家包括中国在内被广泛用作果树、棉花等的杀螨剂,对高等动物的急性口服毒性很低,但它的慢性毒性较大。已有报道显示由DDT合成而来的三氯杀螨醇可使美国红隼的蛋壳变薄,与某些野生动物如佛罗里达湖中鳄鱼雌性化具相关性,甚至导致人体某些恶性肿瘤等。由于三氯杀螨醇性质非常稳定,残留期长,所以过去对该农药研究热点主要是在蔬菜、果品等食品中的残留及降解动态,而对水生生物的毒性尚未见报道,而且对其雌激素活性的报道仅限于小鼠子宫增重法等活体实验方法,周期长且由于生物个体差异等造成灵敏度低。       

吸烟对男性生殖和遗传毒性的研究进展

吸烟作为一个社会问题受到广泛关注,目前研究认为吸烟可对生殖系统存在有害影响。从吸烟对睾丸功能、精液质量、生殖内分泌功能的影响及吸烟对生殖细胞的遗传毒作用几个方面,总结了近几年国内外有关吸烟对男性生殖与遗传毒性研究进展,为进一步研究吸烟的生殖毒性提供参考。     

The effect of ecoestrogens on the development of the mammalian reproductive system

Recently, it has been shown that the environment contains a large variety of chemical substances possessing estrogenic activity (ecoestrogens/environmental estrogens). In this connection, the problem of estrogenic effects exerted by the environment on animal ontogenesis is very important. Here, we review the available data concerning the effects of ecoestrogens on the development of the reproductive system in mammals. We discuss issues of reproductive toxicology related to the effects of these substances during prenatal and postnatal development, with special attention to the effect of ecoestrogens and modern reproductive technologies on preimplantation embryonic development.     

畜禽养殖过程中雌激素的排放及其环境行为

由于存在广泛和较强的内分泌干扰性,环境雌激素越来越受到关注,其中人与动物排放的天然类固醇雌激素(雌酮、雌二醇和雌三醇)具有最强的干扰性。综述了畜禽养殖过程中天然雌激素的排放、危害以及其物化性质,并结合国内外近期研究阐明了天然雌激素的吸附、降解和迁移转化等环境行为。在目前雌激素研究现状的基础上,对未来的研究方向及目标提出了建议。     

MicroRNA在环境毒理学中的研究进展

MicroRNA（miRNA）是一类长为20～24nt的非编码单链小分子RNA,主要存在于真核生物中,具有组织特异性、无开放阅读框等特点,在转录或翻译水平调控基因表达,参与细胞增殖、分化、凋亡,并与炎症、肿瘤等疾病发生、发展密切相关。环境毒理学研究表明,当生物暴露于环境化学物质时,会引起相关miRNA表达发生变化,进而导致其靶基因表达发生改变。因此,有必要明确环境化学物质、miRNA和相关靶基因三者问的作用关系。在环境毒理学研究和环境监测中,miRNA可作为识别环境中化学物质基因毒性和致癌性的生物标记物,并可用于预测环境化学物质对生物体的毒性。     

Species diversity and reproductive mechanisms in Jamaican trees

The flowering and fruiting of the 56 species of tree growing in the forests at c. 1550 m in the western Blue Mountains in Jamaica was studied to see how differences in reproductive biology may relate to maintenance of species diversity. Forty-six of the 56 species have small flowers (log length (mm) × log breadth (mm) 1). Thirty-six are hermaphrodite, 12 dioecious and eight dioecious, monoecious or polygamous. Compatibility tests showed that five (possible seven) of the hermaphrodite species are self-compatible, one hermaphrodite species is probably self-incompatible. Anthesis and individual flower duration are variable within and between species. There is some interspecific temporal separation of flowering over the year, but a peak of species in flower in the drier to early wet season. Pollination syndromes were also studied. Of the 23 important species, 20 are generalist, two wind-pollinated, one bird-pollinated. For all species, 46 are generalist, six wind-pollinated, one, perhaps two, bird-pollinated, and possibly two moth-pollinated. Generalist type flowers are visited by a wide range of potential pollinators and one pollinator, Apis mellifera, visits many different flowers. Dispersal units usually weigh between 10 and 1000 mg, the others are smaller. Of the 23 important species, 18 are adapted for bird dispersal, four for wind dispersal, and one lacks obvious adaptation. For all 56 species 46 are bird-dispersed, eight wind-dispersed, one is ectochoric and one lacks obvious adaptation. Fruiting phenology is markedly seasonal, occurring from June to January, spanning the later drier period and half of the wet season. With one common type of pollination—entomophily, one common type of dispersal—by birds, and little temporal separation over the year in time of flower and fruit production, there seems to be only a small amount of niche separation in the variables studied; and thus the coexistence of many species is not explained by the present observations.     

Effect of housing and environmental enrichment on adrenocortical activity,behavior and reproductive cyclicity in the female tigrina (Leopardus tigrinus) and margay (Leopardus wiedii)

The objective of this study was to evaluate the effects of different captive housing conditions on reproductive cyclicity and adrenocortical activity in adult females of two small‐sized felid species, the tigrina (Leopardus tigrinus; n = 3) and margay (Leopardus wiedii; n = 2). Females were housed as singletons and subjected to three enclosure conditions over successive time periods: Phase I—large, enriched enclosures for 3 months; Phase II—small, empty enclosures for 5.5 months; Phase III—the same small enclosures enriched with branches and nest boxes for 6.5 months. Fecal samples were collected five times weekly throughout the study for analysis of progestagen, estrogen, and corticoid metabolites. On the basis of observed behaviors, stereotypic pacing was more frequent before feeding for all cats, regardless of enclosure conditions. Both species displayed a bimodal activity pattern, with peaks occurring at nightfall and dawn. All animals exhibited agitated behavior, characterized by a high frequency and duration of stereotypic pacing, primarily during the first 3 days after moving to the small empty enclosures. On the basis of hormonal analyses, ovarian follicular activity decreased and corticoid concentrations increased in tigrinas after transfer to the small barren cages compared to the patterns observed in the initial large, enriched enclosures. Corticoid concentrations in tigrinas then declined after small cage enrichment. Margay females exhibited increased corticoid excretion during Phases II and III, but in contrast to tigrinas, concentrations remained high even after cage enrichment. It was further showed that enriching the small enclosures was insufficient to reestablish normal ovarian activity within the time frame of the study for both species. In summary, margay and tigrina females exhibited distinct elevations in corticoid concentrations after transfer from large enriched enclosures to smaller barren cages that corresponded with agitated behavior, especially immediately after transfer. Fecal corticoid concentrations were reduced after cage enrichment in tigrinas, but not in margays. Although only a few individuals were evaluated, data suggest there may be species differences in response to captive environmental conditions. Overall results emphasize the importance of enclosure dimensions and enrichment when designing species appropriate environments for improving the health and reproductive fitness of threatened species. Zool Biol 26:441–460, 2007. © 2007 Wiley‐Liss, Inc.     

The impact of environmental stress on male reproductive development in plants: biological processes and molecular mechanisms

In plants, male reproductive development is extremely sensitive to adverse climatic environments and (a)biotic stress. Upon exposure to stress, male gametophytic organs often show morphological, structural and metabolic alterations that typically lead to meiotic defects or premature spore abortion and male reproductive sterility. Depending on the type of stress involved (e.g. heat, cold, drought) and the duration of stress exposure, the underlying cellular defect is highly variable and either involves cytoskeletal alterations, tapetal irregularities, altered sugar utilization, aberrations in auxin metabolism, accumulation of reactive oxygen species (ROS; oxidative stress) or the ectopic induction of programmed cell death (PCD). In this review, we present the critically stress‐sensitive stages of male sporogenesis (meiosis) and male gametogenesis (microspore development), and discuss the corresponding biological processes involved and the resulting alterations in male reproduction. In addition, this review also provides insights into the molecular and/or hormonal regulation of the environmental stress sensitivity of male reproduction and outlines putative interaction(s) between the different processes involved.