遗传和温度因素对鱼类性别分化相关基因表达及性别比例的影响

鱼类的性别决定机制较为复杂,是遗传和环境共同作用的结果,具有很大的可塑性。随着分子生物技术的不断更新,对鱼类性别决定及分化相关基因的鉴定和研究有了新的进展,环境因子如温度、光照、p H、低氧、水压等均能影响大多数鱼类的性别决定和分化过程。本研究中,阐述了鱼类遗传型性别决定(GSD)和温度依赖型性别决定(TSD)方式,并对TSD与遗传型性别加温度影响(GSD+TE)性别决定机制下,性别决定相关基因在雌雄异型中的表达及结合温度诱导性逆转进行概述,分析了温度对鱼类性别比例的影响,并提出今后应加强对性别决定基因的鉴定、解析和基因功能研究,为科学制定鱼类繁殖计划提供指导。     

遗传和温度因素对鱼类性别分化相关基因表达及性别比例的影响

鱼类的性别决定机制较为复杂,是遗传和环境共同作用的结果,具有很大的可塑性。随着分子生物技术的不断更新,对鱼类性别决定及分化相关基因的鉴定和研究有了新的进展,环境因子如温度、光照、p H、低氧、水压等均能影响大多数鱼类的性别决定和分化过程。本研究中,阐述了鱼类遗传型性别决定(GSD)和温度依赖型性别决定(TSD)方式,并对TSD与遗传型性别加温度影响(GSD+TE)性别决定机制下,性别决定相关基因在雌雄异型中的表达及结合温度诱导性逆转进行概述,分析了温度对鱼类性别比例的影响,并提出今后应加强对性别决定基因的鉴定、解析和基因功能研究,为科学制定鱼类繁殖计划提供指导。     

棘皮动物性别决定与分化研究进展

棘皮动物是重要的海洋渔业资源,中国现有棘皮动物500余种,其中海参和海胆均被誉为"海产八珍",具有极高的经济价值。大多数棘皮动物不存在明显的雌雄二态性,但在性腺色泽、免疫力、激素水平等层面却展现了性别差异,因此,针对棘皮动物性别决定及分化机制展开研究、实现单性群体养殖具有重要的理论和经济意义。本文综述了棘皮动物,尤其是经济棘皮动物(海参、海胆)的生殖对策、性别决定和性别分化遗传基础,并就棘皮动物性染色体的确定、性别连锁分子标记的开发应用、基因编辑技术应用及性激素诱导单性养殖等方面提出未来重点研究建议,以期推动经济棘皮动物性别控制育种工作进程。     

淡水养殖中常见鱼类疾病的防治措施探究

<正>淡水养殖就是用海水之外的淡水资源进行养殖。淡水养殖具有很多优势,其不但投资少,养殖品种灵活,而且淡水养殖生产比较稳定,风险比较小,并且养殖规模在鱼类养殖中占较大比例,因此具有比较成熟的淡水养殖方法与经验。随着养殖业的不断发展,水产养殖效益在不断提高,但在养殖户获得良好效益的同时,也面临着一些鱼类疾病问题,困扰着广大养殖户。甚至有些流行疾病给水产养殖业带来很大冲击,给养水产殖户造成严重损失。文章针对淡水养殖业中常见的鱼类疾病进行分析,且重点分析了几种比较流行的病害,同时提出防治措施,以期为淡水养殖户提供参考。一、淡水养殖鱼类常见疾病发病原因     

基于生物多样性提升的鱼塘湿地生态修复与监测跟踪

长江流域平原水网地区存在大量的坑塘养殖湿地资源,因前期养殖中采用单一目标的高密度、高投入模式,其对区域生态环境造成了严重的负面影响,将废弃的养殖鱼塘改造为小微湿地,成为都市区城市与乡村提升生物多样性的重要实践之一。以本土鸟类、两栖类栖息生境营建为目标,开展上海市嘉定区彭门湿地生态修复实践,探索分析废弃养殖鱼塘转变为多样化生境营建技术措施及其生物多样性恢复效果。监测结果表明,生态修复后鸟类种类逐年增多,国家保护的野生鸟类数量也在增加,挺水植物、浮水植物面积呈增长趋势。彭门湿地生态修复与跟踪监测可为上海地区废弃鱼塘改造为小微湿地生物栖息地提供技术案例参考。     

中间球海胆性别性状的微卫星分析

针对中间球海胆Strongylocentrotus interm edius育苗生产中很难进行活体性别鉴定这一特点,采用组织切片法和微卫星标记分析法对海胆进行观察分析。试验用样品由大连太平洋海珍品有限公司提供,共31只。采用组织切片法鉴别雌、雄个体,发现17只个体为雌性,14只个体为雄性。同时,将31只个体分为雌、雄两个群体,提取性腺组织基因组DNA,利用已经筛选好的11对引物对雌、雄两个群体进行微卫星分析。结果表明,两个群体的遗传多样性没有显著差异;发现INST09-A,INST10-A,INST10-B三个等位基因的频率在两个群体间存在极显著差异(P<0.01),位点INST10在雌、雄两个群体中的基因型频率存在极显著差异(P<0.01)。初步说明这些位点及相应等位基因可能与性别决定位点存在一定的连锁关系。     

利用多不饱和脂肪酸制备新型鱼饲料的研究进展

多不饱和脂肪酸作为鱼类必需的一种营养物质,在提高鱼类繁殖能力,促进生长发育,增强免疫力方面发挥着重要作用。由于鱼自身不能合成多不饱和脂肪酸,只能通过摄食获取,因此在水产养殖中,用多不饱和脂肪酸添加制备新型鱼饲料,提高养殖效益极具前景。文章就多不饱和脂肪酸的种类、结构、性质及其在鱼类养殖中的功能、新型饲料制备及工艺,对国内外的相关研究进行综述。     

董事会性别多样化对内部控制水平影响研究——基于A股的经验证据

文章旨在剖析董事会成员的性别特征对上市公司内部控制水平的影响,从而为各董事会成员构成对内部控制水平的提升作用提供证据。基于2007—2011年我国A股上市公司的研究样本,实证研究发现:(1)女性董事比例与控制环境和信息沟通情况存在显著正相关关系,与企业违规处罚行为负相关;(2)女性董事比例与审计意见类型之间呈显著负相关关系,适当提高女性董事比例不仅能够改善内部控制环境,加强企业信息沟通情况,也能相对减少企业的违规行为。     

浅谈水产养殖过程中饵料的投喂技术

<正>随着水产养殖种类的不断增多以及养殖环境与养殖方式的不断转变,传统的饵料投喂技术已经不能满足现代水产养殖的需求,而饵料投喂技术是养殖主生产过程中重要环节,直接影响着养殖品种的产量和质量的提升。因此,必须综合考虑多方面因素对饵料投喂技术加以改良,从而实现"减量、增收、提质"的目的。本文主要分析了影响养殖对象摄食量的主要因素,重点从投喂原则、投喂数量、投喂方法、投喂次数以及投喂时间等方面讨论了水产养殖过     

建筑性别空间

本文阐述了建筑性别空间的概念,以建筑性别空间形成的原因和中西方不同文化建筑性别空间差异性为出发点,概述了性别空间存在的必然性和研究价值,对现代建筑设计中的性别空间及人性化设计的趋势进行了探讨。     

围绝经期妇女抑郁症与性激素水平相关性探讨

目的:探讨妇女围绝经期抑郁症与性激素水平的关系。方法:对122例围绝经期妇女共采用自评抑郁量表(SDS)进行抑郁症状评估,评定有抑郁症组62例和无抑郁症组60例,另随机选取正常育龄期组58例分别检测血清中血清雌二醇(E2)及卵泡刺激素(FSH)、黄体生成激素(LH)、睾酮(T)、垂体催乳素(PRL)、(孕酮)P的水平。结果:围绝经期两组妇女血清E2水平均比正常育龄期组低,围绝经期妇女抑郁症组血清E2比无抑郁症组低,差异有统计学意义(P<0.05)。围绝经期妇女抑郁症组血清FSH、LH均较无抑郁症组增高,差异有统计学意义(P<0.05)。但无抑郁症组FSH及LH水平与正常育龄期组相比较差异无统计学意义(P>0.05)。围绝经期两组妇女PRL、T水平与正常育龄期组对比差异无统计学意义(P>0.05)。结论:围绝经期抑郁症的发生与雌二醇(E2)减少及卵泡刺激素(FSH)、黄体生成激素(LH)升高有关。     

The geography of the community sex ratios for young children in Newfoundland

Abnormalities of the sex ratio of births may be linked with environmental factors, including diet and pollutants in the general or occupational environments, which in turn can cause ill-health. To examine this relationship in the Province of Newfoundland and Labrador, where a geographical imbalance of mortality has already been identified, we examined the geographical distribution of sex ratios (boys/girls x 100) of young children (0-4 years) in the communities of the Province during recent years. The individual communities of the 1976 and 1981 censuses were assigned to contiguous regions and their component districts. The numbers in the appropriate age-groups in the communities in these two census years were used to calculate a mean sex ratio for each community; each community was allocated, according to the value of its ratio, to one of four predefined categories of ratio. From the numbers of communities belonging to these various categories of sex ratio in the regions and districts, the community sex ratios of these areas (i.e. regions and districts) were derived. As a preliminary assessment of the relationship between sex ratios and mortality, a small group of communities with the highest sex ratios was selected, and the mean standardized mortality ratios (SMRs) for all deaths in those communities were calculated. The community sex ratios of regions and districts declined from east to west. The difference in the ratios between the Avalon region (in the most easterly part of the Province) and the southwest region was statistically significant. Districts with high ratios were frequent, particularly those on the Avalon peninsula in the south-east of the island, whereas low ratios were more frequent on the south-west coast of the island, and a low ratio was also found for the only inland district. Of the communities with statistically reliable numbers, the township of Makkovik in Labrador had the highest sex ratio (100 x 50/25 = 200). The SMR of that community during 1976-82 was statistically elevated at 218. In the small group of communities studied, however, high sex ratios from census data for individual communities were not reliable predictors of high SMRs. Further work is required to clarify the inter-relationships between the sex ratios of the census data, the sex ratios of births, the mortality rates and environmental factors.     

The sex ratios of human and sheep births in areas of high mineralization

The soils of the Tablelands of New South Wales are in general deficient in molybdenum. The sex ratio of lambs bred on these soils averages about 90 rams to 100 ewes. The Tablelands also contain very limited areas of fertile soils which are in the immediate neighbourhood or downstream of proven occurrences of various non‐ferrous metals. The sex ratio of lambs bred on such soils averages about 112 rams to 100 ewes.

The Merseyside Conurbation of England began in 1958 to draw very substantial quantities of water from the Dee River Scheme. There is a large mineral province on the catchment area of the Dee. The Cheshire parts of the conurbation have received the greatest proportion of the new supply, and in association with the new supply the sex ratio of live births has become very significantly more masculine, especially in the Cheshire parts.

Some 7 years after the introduction of Dee water to the conurbation, the death rates began to manifest a very significant decline, the decline being greatest where the consumption of Dee water was greatest.     

Microbial analyses of airborne dust collected from dormitory rooms predict the sex of occupants

We have long known that human occupants are a major source of microbes in the built environment, thus raising the question: How much can we learn about the occupants of a building by analyzing the microbial communities found in indoor air? We investigated bacterial and fungal diversity found in airborne dust collected onto heating, ventilation, and air‐conditioning (HVAC) air filters and settling plates from 91 rooms within a university dormitory. The sex of the room occupants had the most significant effect on the bacterial communities, while the room occupants had no significant effect on fungal communities. By examining the abundances of bacterial genera, we could predict the sex of room occupants with 79% accuracy, a finding that demonstrates the potential forensic applications of studying indoor air microbiology. We also identified which bacterial taxa were indicators of female and male rooms, and found that those taxa often identified as members of the vaginal microbiome were more common in female‐occupied rooms while taxa associated with human skin or the male urogenital microbiota were more common in male‐occupied rooms.     

雌激素对双齿围沙蚕性比、生长和卵母细胞发育的影响

将性未分化的双齿围沙蚕Perinereis aibuhitensis暴露在双酚A和17β-雌二醇两种雌激素下,研究了雌激素对双齿围沙蚕雌雄比例、个体生长、死亡率及卵母细胞发育的影响。结果表明,两种雌激素各浓度下的试验组沙蚕均为雌性。与对照组相比,双酚A浓度为50、100μg/L时,对沙蚕有极显著的促生长作用(P<0.01);浓度为10、150μg/L时,对沙蚕的促生长作用显著(P<0.05);浓度为200μg/L时,对沙蚕的促生长作用不明显;沙蚕的死亡率随双酚A浓度的提高而增加。与对照组相比,当17-β雌二醇浓度为1、5、15 mg/L时,对沙蚕有极显著的促生长作用(P<0.01);浓度为30 mg/L时,对沙蚕的促生长作用显著(P<0.05);浓度为45 mg/L时,对沙蚕的促生长作用不明显;随着浓度的提高,沙蚕的死亡率明显加大。双酚A浓度为10¹50μg/L、17β-雌二醇浓度为1150μg/L、17β-雌二醇浓度为1³0 mg/L时,对沙蚕卵母细胞的生长有明显的促进作用(P<0.01);而双酚A浓度为200μg/L(P<0.05)和17β-雌二醇浓度为45 mg/L(P<0.01)时对卵母细胞的生长有抑制作用。