Peptide primary messengers in plants

The peptide primary messengers regulate embryonic development, cell growth and many other activities in animal cells. But recent evidence verified that peptide primary messengers are also involved in plant defense responses, the recognition between pollen and stigma and keep the balance between cell proliferation and differentiations in shoot apical meristems. Those results suggest that plants may actually make wide use of peptide primary messengers, both in embryonic development and late life when they rally their cells to defend against pathogens and insect pests. The recent advance in those aspects is reviewed.     

细胞凋亡的信号传导途径的研究进展

细胞凋亡是很多基因参与的细胞死亡的一种形式,细胞凋亡从发生到执行的过程存在着不同的信号途径,本文综述了细胞凋亡的三大信号途径：线粒体途径、死亡受体途径和内质网途径。了解细胞凋亡的信号途径及其相互联系有助于人们全面了解细胞凋亡的机制,从而达到对细胞的生死进行调控的目的。     

Differential gene expression profiling in the developed ovaries between the parthenogenetic and bisexual female rice water weevils,Lissorhoptrus oryzophilus Kuschel （Coleoptera： Curculionidae）

The rice water weevil, Lissorhoptrus oryzophilus Kuschel （Coleoptera： Curculionidae）, reproduces by sex in the Southeastern United States, but reproduces by parthenogenesis in California and other invaded regions in Asia and Europe. The objective of this study was to create a parthenogenetic gene expression profile of the rice water weevil in order to gain a better insight into the molecular mechanisms of parthenogenesis in the weevil. Suppression subtractive hybridization （SSH） technique was employed for profiling differential gene expression in the developed ovary between the parthenogenetic and bisexual female rice water weevils. A total of 70 contigs were obtained, and the BLASTX search identified putatively 28 genes with differential functions. According to the cytological process of parthenogenesis, the tubulin alpha-1 chain and signal transduction genes etc. were selected for real time quantitative RT-PCR analyses, and their possible functions related to the molecular mechanism of parthenogenesis were discussed. The tubulin alpha-1 chain and some signal transduction genes may be related to the molecular mechanisms of parthenogenesis of the rice water weevil.     

植物在渗透胁迫下信号转导的级联机制

研究植物在渗透胁迫下信号转导的级联机制,对于有效调控植物在逆境中的生长发育,提高其抗逆性和生存能力具有重要的指导意义．根据近年来国内外的研究成果和报道,综述了植物细胞在渗透胁迫下感受到信号后,相继产生许多信号分子,这些信号分子通过细胞壁-质膜-细胞骨架连续体,引起细胞骨架蛋白变构而传递信息,并与细胞膜蛋白、第二信使系统以及调节因子构成了信号传递网,最终有条不紊地引起特定的基因表达和应答．     

GTPase activating proteins: structural and functional insights 18 years after discovery

The conversion of guanosine triphosphate (GTP) to guanosine diphosphate (GDP) and inorganic phosphate (P_i) by guanine nucleotide binding proteins (GNBPs) is a fundamental process in living cells and represents an important timer in intracellular signalling and transport processes. While the rate of GNBP-mediated GTP hydrolysis is intrinsically slow, direct interaction with GTPase activating proteins (GAPs) accelerates the reaction by up to five orders of magnitude in vitro. Eighteen years after the discovery of the first GAP, biochemical and structural research has been accumulating evidence that GAPs employ a much wider spectrum of chemical mechanisms than had originally been assumed, in order to regulate the chemical players on the catalytic protein-protein interaction stage. Received 25 March 2005; received after revision 31 August 2005; accepted 6 September 2005     

Regulation of angiotensinⅡon Gαq/11 protein of vascular smooth muscle cell and its underlying mechanism

To study the regulation of angiotensin Ⅱ(Ang Ⅱ) on Gαq/11 protein of vascular smooth muscle cell (VSMC) and its underlying mechanism, the protein synthesis was detected by [³H]-leucine incorporation. Gαq/11 expression was measured by Western blot in cultured VSMC of rat aorta. The results showed that the level of Gαq/11 was downregulated after stimulated by AngⅡ for 1—6 h, while it was upregulated significantly by 12—24 h stimulation (P < 0.01) in VSMC. The [³H]-leucine incorporation of VSMC was increased after 24 h Ang Ⅱ stimulation. The biphase regulation of Ang Ⅱ on Gαq/11 protein was blocked by the Ang Ⅱ type Ⅰ receptor (AT1) specific antagnist losartan or PLC inhibitor U73122, while PD98059 did not have this effect. These data indicated that Ang Ⅱ contributed to VSMC hypertrophy by regulating the level of Gαq/11, and this effect was mediated mainly through AT1 receptor-PLC signal transduction pathway.     

The development of taste transduction and taste chip technology

Taste is one of important sensations. The primary taste sensations commonly are categorized as sweet, acid, bitter, salty and umami, of which various tastes are composed. The sensation of taste is initiated by the interaction of tas- tants with receptors and ion channels in the apical micro- villi of taste receptor cells (TRCs) when some sapid molecules (tastants) dissolve in saliva. Subsequently, through a cellular signaling pathway (TRC depolarization and Ca2+ release) gustatory signals a…