Genome Characteristics of the Cyclophragma Undans Nucleopolyhedrovirus: A Distinct Species in Group Ⅰ of Alphabaculovirus

The Cyclophragma undans nucleopolyhedrovirus(Cyun NPV), a potential pest control agent, was isolated from Cyclophragma undans(Lepidoptera: Lasiocampidae), an important forest pest. In the present study, we performed detailed genome analysis of Cyun NPV and compared its genome to those of other Group Ⅰ alphabaculoviruses. Sequencing of the Cyun NPV genome using the Roche 454 sequencing system generated 142,900 bp with a G + C content of 45%. Genome analysis predicted a total of 147 hypothetical open reading frames comprising 38 baculoviral core genes, 24 lepidopteran baculovirus conserved genes, nine Group Ⅰ Alphabaculovirus conserved genes, 71 common genes, and five genes that are unique to Cyun NPV. In addition, the genome contains 13 homologous repeated sequences(hrs). Phylogenetic analysis groups Cyun NPV under a distinct branch within clade ‘‘a' of Group Ⅰ in the genus Alphabaculovirus. Unlike other members of Group Ⅰ, Cyun NPV harbors only nine of the 11 genes previously determined to be specific to Group Ⅰ viruses.Furthermore, the Cyun NPV lacks the tyrosine phosphatase gene and the ac30 gene. The Cyun NPV F-like protein contains two insertions of continuous polar amino acids, one at the conventional fusion peptide and a second insertion at the pretransmembrane domain. The insertions are likely to affect the fusion function and suggest an evolutionary process that led to inactivation of the F-like protein. The above findings imply that Cyun NPV is a distinct species under Group Ⅰ Alphabaculovirus.     

PSⅡ反应中心与捕光天线系统之间的能量传递研究

光合作用的核心问题之一是光合作用的原初反应,即光能的高效吸收、转化和传递的机理。由于PSⅡ与水裂解、氧释放密切相关,因此,PSⅡ反应中心原初反应和能量传递的机理研究具有重要的理论意义。最近,PSⅡ捕光天线复合物以及细菌外周天线复合物的三维空间结构被揭示,反应中心及捕光天线的能量传递规律日益成为新的研究热点之一。近年来,国际上许多实验室采用时间分辨荧光光谱和吸收光谱等技术,利用不同层次的样品,对PSⅡ的原初反应包括能量传递过程的动力学性质进行了研究。但是,不同实验室得到的动力学数据以及对实验数据的解释都存在较大差异。我们实验     

Major role for neuronal NO synthase in curtailing choroidal blood flow autoregulation in newborn pig.

We examined whether nitric oxide (NO) generated from neuronal NO synthase (nNOS) contributes to the reduced ability of the newborn to autoregulate retinal blood flow (RBF) and choroidal blood flow (ChBF) during acute rises in perfusion pressure. In newborn pigs (1-2 days old), RBF (measured by microsphere) is autoregulated over a narrow range of perfusion pressure, whereas ChBF is not autoregulated. N(G)-nitro-L-arginine methyl ester (L-NAME) or specific nNOS inhibitors 7-nitroindazole, 3-bromo-7-nitroindazole, and 1-(2-trifluoromethyl-phenyl)imidazole as well as ganglionic blocker hexamethonium, unveiled a ChBF autoregulation as observed in juvenile (4- to 6-wk old) animals, whereas autoregulation of RBF in the newborn was only enhanced by L-NAME. All NOS inhibitors and hexamethonium prevented the hypertension-induced increase in NO mediator cGMP in the choroid. nNOS mRNA expression and activity were three- to fourfold higher in the choroid of newborn pigs than in tissues of juvenile pigs. It is concluded that increased production of NO from nNOS curtails ChBF autoregulation in the newborn and suggests a role for the autonomic nervous system in this important hemodynamic function, whereas, for RBF autoregulation, endothelial NOS seems to exert a more important contribution in limiting autoregulation.