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SUMMARY: Behavioral experiments concerning a releaser pheromone in the urine of female rainbow trout were performed using immature fish administered orally with 17α-methyltestosterone (MT) during the non-spawning season. The urine was collected by catheter. The frequency of entries of test fish was recorded in each channel scented by test and control solutions in a Y-maze trough. The behavior of both MT-treated and control fish demonstrated that they could not discriminate the differences between distilled and environmental water as control solutions. There was also no difference between MT-treated and control fish when distilled and environmental water were introduced. The MT-treated immature fish were attracted to the channel scented by ovulated female urine. Neither coelomic fluid nor the immature female urine had any effect on the behavioral responses of MT-treated fish, while immature control fish had no preference for the urine of ovulated females. These results suggest in rainbow trout that ovulated female urine contains a releaser pheromone to attract mature males, and that androgens are involved in the sensory mechanisms detecting the releaser pheromone in fish. 相似文献
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牛胚胎移植技术已趋于成熟。我国新疆牧科院用一步细管法移植牛冻胚受胎率达41%;牛和羊鲜胚四分胚移植也产下1头犊牛和6只羔羊。家畜体外受精,因卵子体外成熟和受精卵体外培养尚不过关,目前仍停留在实验室阶段。胚胎性别鉴定,1990年Koopman发现单拷贝基因,该基因是Y染色体的性决定区,命名为SRY,可利用PCR技术制成雄性特异DNA探针盒,进行马、牛、羊、猪早期胚胎性别鉴定。北京农学院等单位用PCR扩增牛SRY序列进行奶牛胚胎性别鉴定准确率达100%。英、日、法等国已获得牛胚胎细胞核移植后代;我国也获得1只核移植兔。北农大和新疆牧科院合作以绵羊精子为载体导入牛生长激素基因rMTbGH DNA成功,外源基因整合率为3%。 相似文献
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赤眼蜂寄生行为研究(Ⅳ)—子代数量分配和子代性分配 总被引:1,自引:0,他引:1
本文在对赤眼蜂性控行为研究的基础上〔3〕,进一步探讨了不同种赤眼蜂在同一种寄主不同分布以及同一蜂种(松毛虫赤眼蜂 Trichogramma dendrolimi)在不同种寄主上的子代数量分配和子代性分配问题。研究结果表明,赤眼蜂具有根据寄主卵体积大小分配及调整其子代数量和子代性别的能力,在不同体积的寄主上具有明显不同的子代数量安排策略和子代性安排策略。在同一种寄主卵上,不同种的赤眼蜂对子代性分配的安排存在着较明显的种间差异.在米蛾卵上,松毛虫赤眼蜂的第一雄卵主要在其第一产卵序产出,稻螟赤眼蜂的第一雄卵主要在其第二产卵序产出,拟澳洲赤眼蜂产第一雄卵的位置比较分散,主要分布在前三卵序。松毛虫赤眼蜂大约每产6粒雌卵而产1粒雄卵;稻螟赤眼蜂和拟澳洲赤眼蜂大约每产5.33和3.37粒雌卵而产1粒雄卵(见表2).寄主卵的体积不同,雌蜂在不同寄主上所分配的子代数量也明显不同。松毛虫赤眼蜂在每粒米蛾卵上只安排1粒蜂卵;在每粒马尾松毛虫卵上平均安排18.64粒蜂卵;在每粒“人造卵”上平均安排33.15粒,在柞蚕卵上平均安排77.43粒蜂卵(见表3)。随着寄主卵体积的增大,雌蜂产第一雄卵的时间后移,在松毛虫卵上,松毛虫赤眼蜂雌蜂在产下第一粒雄卵后,大约以每产16粒雌卵而产1粒雄卵;在柞蚕卵上,大约每隔15粒雌卵产1粒雄卵;在“人造卵”上,产雄卵的间隔大约为9粒雌卵。 相似文献
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AIM To investigate the effects of astragaloside on the levels of sex hormone and oxidative stress in rats with polycystic ovary syndrome (PCOS). METHODS Female SD rats (n =60) were randomly divided into normal control group, model group, Diane-35 (0.339 2 mg/kg) group, low dose astragaloside (12.5 mg/kg) group and high dose astragaloside (50 mg/kg) group, with 12 rats in each group. The PCOS model was induced by letrozole (1 mg/kg), which was administered by gavage once a day for 3 weeks. After administration, the estrus cycle of the rats was observed by vaginal smear, and the ovarian index was calculated. HE staining was used to observe the histopathological changes of the ovaries. Serum levels of the sex hormones testosterone (T), estradiol (E2), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured by ELISA. The levels of superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) in serum and ovarian tissue were detected by colorimetry, and the protein levels of steroidogenetic acute regulatory protein (StAR) and apoptosis-related proteins cleaved caspase-3, Bax and Bcl-2 in ovarian tissue were detected by Western blot. RESULT Compared with control group, the oestrous cycle of the rats in model group was disorder, and the ovarian index was increased, ovary was polycystic. The serum levels of T, LH and MDAwere significantly increased (P <0.05), while the contents of E2, FSH and the activities of GSH-Px and SOD were significantly decreased (P <0.05). The levels of MDA, StAR, cleaved caspase-3 and Bax proteins in ovarian tissue were significantly up-regulated (P <0.05). GSH-Px and SOD activities and Bcl-2 protein levels were significantly down-regulated (P <0.05). CONCLUSION Astragalosideeffectively balances the levels of sex hormone in PCOS rats and relieves the oxidative stress injury, the mechanism may be related to the inhibition of StAR expression. 相似文献