Steroidogenic factor 1 (SF-1), an essential nuclear receptor, plays key roles in steroidogenic cell function within the adrenal cortex and gonads. It also contributes to reproductive function at all three levels of the hypothalamic-pituitary-gonadal axis. SF-1 regulates genes in the steroidogenic pathway, such as LHbeta, FSHbeta, and steroid hydroxylase. Abundant evidence suggests that nitric oxide (NO) has an important role in the control of reproduction due to its ability to control GnRH secretion from the hypothalamus and the preovulatory LH surge in pituitary gonadotropes. Recently, we cloned and characterized the promoter of mouse neuronal NO synthase (nNOS). nNOS is localized at all three levels of the hypothalamic-pituitary-gonadal axis to generate NO. We find that its major promoter resides at exon 2 in the pituitary gonadotrope alphaT3-1 cell line and that there is a nuclear hormone receptor binding site in this region, to which SF-1 can bind and regulate nNOS transcription. Mutation of the nuclear hormone receptor binding site dramatically decreases basal promoter activity and abolishes SF-1 responsiveness. A dominant negative of SF-1, in which the transactivation (AF-2) domain of SF-1 was deleted, inhibits nNOS exon 2 promoter activity. Dosage-sensitive reversal- adrenal hypoplasia congenita critical region on the X chromosome, gene 1 (DAX-1), which colocalizes and interferes with SF-1 actions in multiple cell lineages, negatively modulates SF-1 regulation of nNOS transcription. These findings demonstrate that mouse nNOS gene expression is regulated by the SF-1 gene family in pituitary gonadotropes. nNOS, a member of the cytochrome p450 gene family, could be one of the downstream effector genes, which mediates SF-1's reproductive function and developmental patterning.

Aims Euryodendron excelsum, an extremely endangered species of Theaceae, is endemic to China. However, there are few studies on the cause of population structure change of E. excelsum, and its conservation strategy is not perfect. We studied the age structure and dynamics of the E. excelsum population, compared them with the research results in 2007, and analyzed the changes of the E. excelsum population in the last ten years, so as to provide scientific reference for the effective protection and management of the E. excelsum population. Methods Based on field investigation data, the values of parameters such as standard life table, survival curve, killing power and life expectancy curve were established, and the structure status of the E. excelsum population was analyzed as well. The community composition was analyzed using DET's multiple analysis method. Important findings (1) The analysis of population dynamic indices showed that dynamic indices (V pi and V′ pi ) of the wild E. excelsum population were all less than 0. The survival curve of the whole population generally fit a Deevey-III type curve, suggesting a declining population. The number of young individuals was abundant, but impaired development, and hence cannot support the population growth in time. (2) The analysis of survival curve, killing power and life expectancy showed that the sapling, small tree II and middle tree II obstructed the natural population renewal. (3) The Sanjia and Bajia group seedlings of E. excelsum decreased by 39.3% and 71.9%, respectively. The seedling conversion rate of Sanjia group was nearly 1/2 times lower than the Bajia group of E. excelsum. Human interference was the main driver of population decline of E. excelsum. In addition, the conservation strategy that has been implemented is not suitable for the current situation.

In this paper, the research progress of catalysts for selective oligomerization of ethylene was reviewed in terms of the cocatalysts, ligand structure, oxidation state of the iron metal atom center and immobilization of homogeneous catalysts.