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首页> 外文学位 >Sex determination in Nile tilapia, Oreochromis niloticus: Gene expression, masculinization methods, and environmental effects.
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Sex determination in Nile tilapia, Oreochromis niloticus: Gene expression, masculinization methods, and environmental effects.

机译：尼罗罗非鱼，尼罗罗非鱼的性别决定：基因表达，男性化方法和环境影响。

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摘要

Sex differentiation in fish is a labile process that allows sex inversion in several species. The inherent capacity of fish germ cells to differentiate into oocytes or spermatocytes constitutes a key factor allowing for functional sex inversion. This thesis set out to determine the mechanism involved in steroid-induced sex differentiation of Nile tilapia, Oreochromis niloticus , by searching for differential expression of unique genes during the process. In addition, the studies documented the persistence of methyltestosterone (MT) in the environment after oral administration, and investigated the capabilities of short-term immersions in steroids for masculinizing tilapia fry as an alternative method. A significant leakage of MT to the rearing water and its subsequent accumulation in the sediments was detected after oral administration of the steroid. In addition, evidence was found for a significant effect of environmental conditions on the masculinizing efficacy of oral administration of steroids. Low levels of masculinization were obtained when MT was allowed to remain in the system. Results from short-term immersions in steroids indicated that the labile period for masculinization by immersion of Nile tilapia fry reared at 28°C occurs between 11 and 16 days post fertilization (dpf). Two three-hour immersions in trenbolone acetate at 11 and 13 dpf yielded the highest number of males. Time of immersion, length of the treatment, dosage, density, solvent vehicle, and number of immersions significantly affected the outcome of immersion trials. Heterogeneity of developmental stages, developmental rate, and sensitivity of progeny to steroids may play important roles in the efficacy of immersion treatments. The expression of unique mRNAs during the process of sex inversion was identified through the use of suppression subtractive hybridization. This technique allowed for the sequencing of 165 clones from which 61 proteins have been identified. A significant number of these genes seem related to the anabolic effects of trenbolone acetate. In addition, 12 genes were identified that are related to reproductive tissues; seven of which have unique or enriched expression in the testes. Some of the genes and protein products that have been identified are linked to gonadal development and testicular protein synthesis in other species.
机译：鱼的性别分化是一个不稳定的过程，可以使几种物种发生性别反转。鱼生殖细胞分化为卵母细胞或精母细胞的固有能力构成了允许性功能倒置的关键因素。本论文着手通过寻找过程中独特基因的差异表达，来确定类固醇诱导尼罗罗非鱼（Oreochromis niloticus）性别分化的机制。此外，研究记录了口服后环境中甲基睾丸酮（MT）的持久性，并研究了短期浸泡在类固醇中以男性化罗非鱼苗作为替代方法的能力。口服类固醇后，检测到MT大量流到饲养水中，并随后沉积在沉积物中。此外，还发现环境条件对口服类固醇的男性化功效有重大影响。当MT保留在系统中时，男性化程度低。短期浸泡在类固醇中的结果表明，通过在28°C下饲养的尼罗罗非鱼鱼苗浸泡进行男性化的不稳定期发生在受精后（dpf）11至16天之间。分别在11和13 dpf的醋酸群勃龙中浸泡两次三个小时，得出的男性数量最多。浸泡时间，处理时间，剂量，密度，溶剂载体和浸泡次数会显着影响浸泡试验的结果。发育阶段的异质性，发育速度和子代对类固醇的敏感性可能在浸泡治疗的功效中起重要作用。通过使用抑制性消减杂交来鉴定性倒置过程中独特mRNA的表达。这项技术可对165个克隆进行测序，从中鉴定出61个蛋白质。这些基因的大量似乎与醋酸群勃龙的合成代谢作用有关。另外，鉴定出与生殖组织有关的12个基因；其中有七个在睾丸中具有独特或丰富的表达。已确定的某些基因和蛋白质产物与其他物种的性腺发育和睾丸蛋白质合成有关。

著录项

  • 作者

    Contreras Sanchez, Wilfrido Miguel.;

  • 作者单位

    Oregon State University.;

  • 授予单位 Oregon State University.;
  • 学科 Biology Molecular.; Biology Animal Physiology.; Agriculture Fisheries and Aquaculture.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 193 p.
  • 总页数 193
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 分子遗传学;生理学;水产、渔业;
  • 关键词

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