Association of reproductive traits with captive- versus wild-sourced birds in trade

The wildlife trade is a billion-dollar global business, involving millions of people, thousands of species, and hundreds of millions of individual organisms. Unravelling whether trade targets reproductively distinct species and whether this preference varies between captive- and wild-sourced species is a crucial question. We used a comprehensive list of all bird species traded, trade listings and records kept in compliance with the Convention on International Trade in Endangered Species (CITES), and a suite of avian reproductive parameters to examine whether wildlife trade is associated with particular facets of life history and to examine the association between life-history traits and captive- and wild-sourced traded volumes over time. Across all trade, CITES listing, and CITES trade, large birds were more likely to be traded and listed, but their longevity and age at maturity were not associated with CITES listing or trade. We found species across almost the full range of trait values in both captive and wild trade between 2000 and 2020. Captive trade volumes clearly associated with relatively longer lived and early-maturing species; these associations remained stable and largely unchanged over time. Trait–volume associations in wild-sourced trade were more uncertain. Only body mass had a clear association, and it varied from negative to positive over time. Although reproductive traits were important in captive-sourced trade, species-level variation dominated trade, with even congeneric species varying greatly in volume despite similar traits. The collection and incorporation of trait data into sustainability assessments of captive breeding facilities are crucial to ensure accurate quotas and guard against laundering.     

Population and Environment： Necessary Transition Initiatives for Developing Countries

Now environment is an important topic in academic field. Many researches focus on the negative outcomes of nature which are being continually created by human and much attention has been paid to how the environment is protected through integrated research, movement and policy. But few studies are concentrated on population and environment and are to find out the interconnectivity and underlying mechanism that have an effect on people＇s preferring additional children and perception to environment. Many researchers claim that population growth is a great problem for environment but they do not provide the indepth integrated knowledge and mechanism that influence fertility trend and environmental problems. It is very crucial to develop practical and concrete initiatives to confirm a transition to reduce population growth and redirect the perception on population and environment.     

The sexual and reproductive rights of internally displaced women: the embodiment of Colombia's crisis

As of 30 June 2006, more than 3.5 million Colombians are internally displaced persons (IDPs), the second largest IDP population in the world after that of Sudan. While most IDP studies treat the plight of internally displaced women (IDW) as an isolated phenomenon, this paper demonstrates that their situation reflects Colombia's chronic cultural, political and socio-economic crisis. This paper uses a sexual and reproductive rights framework to establish a connection between IDW and Colombia's culture of violence, discrimination and inequality. The effects of this culture of violence, discrimination and inequality are highlighted during a discussion of the rights to health, reproduction, privacy, physical integrity, education, and freedom from violence and sexual exploitation. This paper argues that a holistic understanding of Colombia's humanitarian emergency is essential to improving the lives of IDPs. It ends with some concrete, short-term recommendations to meet some of the needs of IDPs and other vulnerable populations.     

亚急性镉暴露对雄性黑斑蛙生殖毒性的研究

在实验条件下,将健康性成熟雄性黑斑蛙暴露于2.5、5.0、7.5和10.0mg·L-1浓度的镉溶液中14d,观察和分析黑斑蛙的精子数量、精子畸形率,测定精巢组织中酸性磷酸酶(ACP)、乳酸脱氢酶(LDH)、丙二醛(MDA)、谷胱甘肽(GSH)、超氧化歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)的水平和活力,以探讨镉对黑斑蛙的雄性生殖毒性及作用机理.结果表明:①镉可引起黑斑蛙精子数量减少和精子畸形率增加,且呈剂量-效应关系;②镉可引起精巢ACP、LDH酶活性的降低,且随染毒剂量的增加而降低;③镉可引起精巢组织MDA、GSH含量的升高,引起抗氧化酶SOD、GSH-Px活性的降低.由此推论,亚急性镉暴露对黑斑蛙精巢有明显的毒性作用,其机制与镉致黑斑蛙精巢组织标志酶活力的降低和精巢脂质过氧化作用有关.     

Mate choice games, context-dependent good genes, and genetic cycles in the side-blotched lizard, Uta stansburiana

According to mate choice models, a female should prefer males with traits that are reliable indicators of genetic quality which the sire can pass on to their progeny. However, good genes may depend on the social environment, and female choice for good genes should be context dependent. The side-blotched lizard, Uta stansburiana, exhibits genetically based throat colors (orange, blue, or yellow) that could be used as a sexually selected signal since they reliably predict the genetic quality of mates. The frequencies of male and female morphs cycle between years, and both male and female morphs have an advantage when rare; thus genetic quality will depend on morph frequency. A female should choose a sire that maximizes the reproductive success of both male and female progeny. We examine a game theoretical model that predicts female mate choice as a function of morph frequency and population density. The model predicts the following flexible mate choice rule: both female morphs should prefer rare males in ’boom years’ of the female cycle (e.g., ’rarest-of-N rule’), but prefer orange males in ’crash years’ of the female cycle (’orange-male rule’). Cues from the current social environment should be used by females to choose a mate that maximizes the future reproductive success of progeny, given the social environment of the next generation. We predict that the cue is the density of aggressive orange females. In the side-blotched lizard, cycling mate choice games and context-dependent mate choice are predicted to maintain genetic variation in the presence of choice for good genes. Received: 8 March 2000 / Revised: 26 August 2000 / Accepted: 4 September 2000     

城市河涌水对C57BL/6J小鼠生殖和发育的影响

前期研究发现广州市周边小型企业集中点和生活区下游河涌水样中存在较高浓度的AhR激活物污染.为考察河涌水中是否存在对生殖和发育产生影响的TCDD类似物,本研究以检出河涌水样激活物平均值标准品TCDD做阳性对照,C57BL/6J雌性小鼠为模型进行了三代生殖毒性实验,了解长期暴露对动物生殖和发育产生的毒性影响.成年雌性小鼠4...     

邻苯二甲酸丁基苄酯的生殖毒性及其作用机制

为评价邻苯二甲酸丁基苄酯在体内的慢性毒性,以1000mg/kg、500mg/kg、250mg/kg剂量连续染毒大鼠6周、20周.结果表明:邻苯二甲酸丁基苄酯能引起雄鼠睾丸(p＜0.01)、附睾和前列腺重量的减少(p＜0.05)和肝脏肿大(p＜0.01),改变睾丸(p＜0.01)、前列腺(p＜0.05)、肝脏(p＜0.01)的组织病理学,尤其引起睾丸曲细精管萎缩、变性,各级生精细胞减少,生精上皮内生精细胞和Sertoli细胞结构明显紊乱,细胞间连接结构消失.降低血清中γ-G(p＜0.01)、ALP(p＜0.05)活性、睾酮水平(p＜0.01),增加LDH活性(p＜0.01)和FSH水平(p＜0.01),呈一定的量-效和时-效关系.结合组织病理和性激素及酶活性的改变,揭示该化合物睾丸毒性的靶细胞是支持细胞,其次是生精细胞,作用的靶点是细胞内的线粒体.邻苯二甲酸丁基苄酯对雌鼠的损害只引起子宫的增大和轻微炎症表现及血清ALP酶活性的降低(p＜0.05).充分说明了邻苯二甲酸丁基苄酯对动物的干扰有明显的性别差异,对雄性的危害要远远大于对雌性的损害.     

草甘膦对雄性大鼠睾酮合成的影响

探讨草甘膦亚慢性染毒对雄性大鼠睾酮合成的影响。雄性SD大鼠按体重随机分为对照组(0 mg·kg~(-1))、低剂量组(50 mg·kg~(-1))、中剂量组(200 mg·kg~(-1))和高剂量组(800 mg·kg~(-1)),连续灌胃染毒,第4、8和12周时分别处死一批动物,采集血液和脏器。放射免疫分析法检测大鼠血清中卵泡刺激素(follicle stimulating hormone,FSH)、黄体生成素(luteinizing hormone,LH)、睾酮(testosterone,T)、雌二醇(estradiol,E2)水平; HE染色法(苏木精-伊红染色法)观察睾丸病理学变化;免疫组化法检测3β-羟基类固醇脱氢酶(3beta-hydroxysteroid dehydrogenase,3β-HSD)、类固醇激素合成急性调节蛋白(steroid synthesis of acute regulatory protein,St AR)、细胞色素P450胆固醇侧链裂解酶(cytochrome P450 cholesterol side chain lyase,P450scc)和17β-羟基类固醇脱氢酶(17beta-hydroxysteroid dehydrogenase,17β-HSD)蛋白表达水平。随染毒剂量和时间的增加,大鼠血清FSH和T水平呈下降趋势,第12周高剂量组FSH水平明显低于对照组(P0.05),第8周和第12周高剂量组T水平明显低于对照组(P0.05),LH和E2水平各组间无统计学差异(P0.05)。组织病理学可见中、高剂量组睾丸生精小管、生精细胞、间质区结构被破坏。随草甘膦染毒剂量的增加,St AR和P450scc蛋白表达水平与对照组相比显著下降(P0.05),3β-HSD和17β-HSD蛋白表达水平在各组间无差异(P0.05)。草甘膦能降低血清T水平,抑制T合成相关蛋白St AR和P450scc的表达,干扰T的合成过程,具有雄性生殖毒性作用。     

飞机草的繁殖能力与种子的萌发特性

飞机草（Chromolaena odorata）是一种入侵性极强的外来杂草,现正在我国南部地区迅速传播,其繁殖特性与种子萌发对环境条件的适应能力是成功入侵扩散的前提。采用野外调查与室内试验相结合的方法,研究了飞机草的繁殖能力与种子的萌发特性。结果表明,飞机草能够进行无性繁殖,但其有性生殖能力更强,成熟植株的种子生产量高,种子质量轻,并且具有冠毛等附属结构。环境因子能够影响飞机草种子的萌发,其萌发的最适温度约为28℃,萌发过程中不需要特别的养分供应,并且能够忍耐一定程度的干旱胁迫。酸性环境能够促进飞机草种子的萌发,但当pH降至2.0时,其发芽率显著降低。掩埋处理能够抑制飞机草种子的萌发,当埋藏深度达3.0 cm时,所有的种子均不能正常萌发与出苗。     

微囊藻毒素-LR污染饮水的健康风险及其机制

水体富营养化导致藻类繁殖和水华暴发从而使得藻类释放大量藻毒素,已经演变成为严重的公共卫生问题之一。微囊藻毒素通过饮水严重危害动物和人类的健康安全,最主要的靶器官是肝脏,从而造成肝细胞功能缺陷,比如黄疸和磷酸化活性改变。这些毒性效应主要表现为对磷酸酶的抑制和蛋白磷酸酶活性的调节。综上,微囊藻毒素会造成组织结构损伤、凋亡,即使在低浓度下,也会影响细胞周期,导致肿瘤发生。