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71.
养殖三龄暗纹东方性腺发育及其毒性   总被引:1,自引:0,他引:1  
对三龄养殖暗纹东方Tun性腺发育情况进行了较全面观察与测量,同时对其卵巢和肝脏的毒性进行了检验,结果表明,养殖三龄暗纹东方Tun雌鱼和雄鱼性腺均发育到了第Ⅳ期,成熟系数在19.8-26.0之间。  相似文献   
72.
探讨12 h光照、12 h黑暗交替(LD)光制下松果体N-乙酰转移酶(NAT)基因的昼夜节律性表达。SD大鼠在LD光制下饲养4周后,在一昼夜内每隔4h采集一组松果体组织,提取总RNA,进行竞争性定量RT-PCR,测定不同昼夜时点(ZT)样品中NAT基因mRNA的相对表达量。用余弦函数获取节律参数,并经振幅检验分析是否存在昼夜节律。结果表明松果体NAT基因mRNA表达呈现昼夜节律性振荡(P<0.05),峰值(mRNA水平为1.07±0.23)和谷值(mRNA水平为0.61±0.15)分别位于ZT16和ZT4,峰值相位-241.80±14.94,振幅0.23±0.13,中值0.84±0.11。证实LD光制下松果体NAT基因存在明显的昼低夜高节律性表达。  相似文献   
73.
研究了与虫蜡生产关系密切的二龄雄幼虫蜡腺的发育.发现背腺分批发育现象明显,腹腺发育较同步.泌蜡活动与蜡腺发育有关:第一次泌蜡盛期是多数背腺同时成熟、分泌的结果;第二次泌蜡盛期与蜡腺的生理状态有关,绛色细胞可能起着重要作用.  相似文献   
74.
Juvenile hormone bisepoxide (JHB3) and juvenile hormone III (JH III) both inhibited the in vitro production of ecdysteroids by ring glands and brain-ring gland complexes from third instar post-feeding larvae ofDrosophila melanogaster in a reversible manner, although JHB3 had greater efficacy. The JH III and JHB3 precursor, methyl farnesoate, did not affect ecdysteroid production. The in vitro synthesis of total detectable JH (JHB3+JH III+methyl farnesoate) by the corpus allatum portion of the isolated ring gland was also inhibited reversibly in the presence of exogenous JHB3 and JH III, but not by methyl farnesoate. These data indicating negative feedback are in agreement with the accepted dogma of endocrine gland regulation.  相似文献   
75.
斯坦尼小体提液对垂体体外跌卵和催产的影响   总被引:2,自引:1,他引:1  
本文采用对蟾蜍进行体外跌卵和对团头鲂进行人工催产的试验方法,探讨了鲫鱼(♀)斯坦尼小体提取液对脑垂体提取液体外跌卵和人工催产的协同作用.结果表明,春季鲫鱼(♀)斯坦尼小体提取液对脑垂体提取液的体外跌卵和人工催产均有协同作用,主要表现为使跌卵率和产卵量明显提高.但这两方面的协同作用都必须在其含量达到一定程度时才能显示出来.  相似文献   
76.
Summary We investigated the functions of the testicular glands of blenniid fishes by fine-structural and histochemical methods. These glands function in the differentiation and nutrition of germ cells, in the secretion of sialomucins, in phagocytosis of germ cells, and in lipid storage.  相似文献   
77.
78.
Summary 3-Ethyl-2,5-dimethylpyrazine, found in the poison gland of workers, induces trail following in the Mediterranean harvester antMessor bouvieri. The poison gland contains on average 9 ng of this trail pheromone component. The alkaloids anabasine and anabaseine are also present in this gland, but induce no reaction in workers. Trail following is also induced by substances present in the Dufour gland, but the combined effect of both glands shows no synergism.  相似文献   
79.
During the last decade we have learned much on physiological changes in the secretion of the pineal hormone melatonin (MLT) in man. Reportedly, there is little or no MLT secreted before age 3 months. Then MLT production commences, becmes circadian, and reaches highest nocturnal levels at the age of 1–3 years. During all of childhood nocturnal peak levles drop progressively by 80% until adult levels are reached. This alteration appears to be the consequence of increasing body size in face of constant MLT production during childhood. The biological significance of this MLT alteration is presently unknown. Because of conceptual considerations, major depressive syndrome (MDS) and seasonal affective disorder (SAD) have been in the focus of pineal research for several years. Although in these disorders alterations in MLT levels could not be substantiated, light therapy, a consequence of this research, was discovered as an effective treatment for SAD and perhaps for MDS. In addition, there is some recent evidence for low MLT levels in schizophrenia. Finally, the potential effect of MLT in neuroimmunoendocrine interactions is presently explored. Reportedly, in vitro studies and animal experiments give evidence for a modulatory role of MLT in the immune response. However, the exact way of this possible action of MLT remains to be clarified. Clinical studies are too scant for a meaningful estimation of MLT's involvement in human neuroimmunoendocrine interactions.  相似文献   
80.
The composition of the Dufour gland of the antC. scutellaris has been reinvestigated by gas chromatography/mass spectrometry. The major components of the gland are (2E,5E,12Z)-4-oxoheneicosa-2,5,12-trien-1-ol acetate (1a) its 14 and 16 double bond isomers (1b and1c), and the corresponding (Z,Z)-dienes5a and5b, all containing an acetylated C21 chain. The previously proposed structures1d, 1e, and5c, which are based on an homologous acetylated C23 chain, correspond to minor derivatives present in the gland. Traces of acetylated C19 homologs, tentatively identified as1g-1i, have also been found. The Dufour gland contents of the two other EuropeanCrematogaster species have also been studied.C. auberti is very similar toC. scutellaris in producing mainly1a, 1b and1c, together with the same higher and lower homologs, but it lacks the dienic derivatives5, whereasC. sordidula contains essentially the acetylated C19 compounds1g, 1h, and1i, accompanied by acetylated C17 homologs.  相似文献   
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