Hyperprolactinemia and estrogen-induced rhythms in LH and prolactin release in the ovariectomized rat

Short-term (9 days) hyperprolactinemia induced by pituitary grafts reduced basal plasma LH levels in ovariectomized rats whereas long-term (31 days) grafts increased basal LH levels. Although long-term grafts inhibited estradiol-induced prolactin surges, hyperprolactinemia had no effect on the LH surge. It is concluded that the estrogen-treated ovariectomized rat is not suitable for studying the effects of hyperprolactinemia on LH release.     

Negative phototaxis inDrosophila associated with a morphological change in the compound eye

Summary The ultrastructure of the compound eyes of several photonegative selection lines and their unselected photopositive controls of five species of themelanogaster subgroup was analyzed. A qualitative phenotypic change concerning the rhabdomeres in one of the photonegative selection lines ofD. mauritiana could be detected. It was proved that this structural aberration of the rhabdomeres is caused by a parallel mutation of the mutantora (outer rhabdomeres absent) ofD. melanogaster.     

Thiarubrine A, a bioactive constituent of Aspilia (Asteraceae) consumed by wild chimpanzees

Two African species of Aspilia (Asteraceae), which are used medicinally by man and which are eaten by wild chimpanzees in an unusual manner, were found to contain the potent antibiotic thiarubrine A as a major leaf phytochemical. Its presence in leaf material strengthens the view that the feeding behavior of wild chimpanzees is related to special physiological or pharmacological effects on the animals.     

Role of active oxygen species in diethyldithiocarbamate-induced gastric ulcer in the rat

Diethyldithiocarbamate, an inhibitor of Cu,Zn-superoxide dismutase, was recently found to be ulcerogenic in the rat stomach, and active oxygen species were found to be responsible for its ulcerogenicity. To clarify which active oxygen species play a role in ulcerogenesis, the effects of various scavengers and iron-chelators were studied. As superoxide dismutase and catalase reduced the ulcerogenesis induced by diethyldithiocarbamate, the superoxide radical and hydrogen peroxide were considered to play a pathogenic role in this ulcer model.     

氯化钙型锌锰干电池的研制

研制了一种新型电解液，其成分以氯化钙为主，制成的成品电池放电性能优良，具有耐低温，防温液，贮存期长等优点。     

萄葡糖电合成葡葡糖酸锌

在无隔膜的电解槽中,用成对电合成法,制取了葡萄糖酸及山梨糠醇,完成了葡萄糖酸由钠盐向锌盐的转化,最佳操作条件:pH 9～10,温度55℃,葡萄糖和NaBr浓度均为0.8mol/L,电解的电流密度10mA/cm~2,电流浓度0.3F·mol~(-1)。在此条件下有效电耗为57.5%。     

金属离子水化能计算的新模型

本文在考虑离子的静电效应、极化效应、配位场效应及电子效应对金属离子水化能影响的基础上提出了金属离子水化能计算新模型：其计算值与实验值相吻合，并优于其他文献的计算值．     

Histone H3 lysine 9 methylation is an epigenetic imprint of facultative heterochromatin.

Post-translational modifications of histone amino termini are an important regulatory mechanism that induce transitions in chromatin structure, thereby contributing to epigenetic gene control and the assembly of specialized chromosomal subdomains. Methylation of histone H3 at lysine 9 (H3-Lys9) by site-specific histone methyltransferases (Suv39h HMTases) marks constitutive heterochromatin. Here, we show that H3-Lys9 methylation also occurs in facultative heterochromatin of the inactive X chromosome (Xi) in female mammals. H3-Lys9 methylation is retained through mitosis, indicating that it might provide an epigenetic imprint for the maintenance of the inactive state. Disruption of the two mouse Suv39h HMTases abolishes H3-Lys9 methylation of constitutive heterochromatin but not that of the Xi. In addition, HP1 proteins, which normally associate with heterochromatin, do not accumulate with the Xi. These observations suggest the existence of an Suv39h-HP1-independent pathway regulating H3-Lys9 methylation of facultative heterochromatin.