肝细胞生长因子对四氯化碳损伤原代培养大鼠肝细胞的保护…

本工作采用无血清原供培养大鼠肝细胞法,观察了重组人肝细胞生长因子对四氯化碳致大鼠肝细胞损伤的保护作用。结果表明,ｒ－ｈＨＧＦ对ＣＣｌ４染毒肝细胞有明显的保护作用。ｒ－ｈＨＧＦ保护组较ＣＣｌ４染毒组细胞存活率显著升高,细胞内丙氨酸转氨酶,钾离子漏出明显降低。     

Manipulation of monoubiquitin improves salt tolerance in transgenic tobacco

Ubiquitin (Ub) is regarded as a stress protein involved in many stress responses. In this paper, sense and antisense transgenic tobacco plants, as well as the wild type and vector control, were used to study the role of Ub in salt tolerance of plants. In sense Ta-Ub2 transgenic tobacco plants, there was higher expression of Ub protein conjugates than in the wild type and vector control, but the reverse trend was observed in antisense Nt-Ub1 transgenic plants. The germination rate of tobacco seed, growth status and photosynthesis of the tobacco plants suggested that over-expressing Ub promoted the growth of transgenic tobacco plants and enhanced their salt tolerance, but the opposite effect was seen in plants with repressed Ub expression. Changes in antioxidant capacity may be one of the mechanisms underlying Ub-regulated salt tolerance. Furthermore, improved tolerance to a combination of stresses was also observed in the sense transgenic tobacco plants. These findings imply that Ub is involved in the tolerance of plants to abiotic stress.     

云南省4种伊蚊的乙型脑炎病毒分离物的研究

在云南省西南边境９县市捕获伊蚊属雌性成蚊１６种１９３６７只,用细胞法和乳鼠法分离病毒。从１８５批６４９１只白纹伊蚊中分离到病毒２株,从５０批１６０５只剌扰伊蚊中分离到病毒２株,从２３批７７２只窄翅伊蚊中分离到病毒２株,从４批１０３只阿萨姆伊蚊中分离到病毒１株。其它１２种共１０３９６只伊蚊的病毒分离物为阴性。分离到的７株病毒经免疫荧光、酶免疫、血凝抑制和中和试验鉴定,均为乙型脑炎病毒（ＪＥｖｉｒｕｓ）。白纹伊蚊是野外竹林的优势蚊种。分析认为白纹伊蚊在当地乙型脑炎病毒保存和传播中起重要作用,刺扰伊蚊、窄翅伊蚊和阿萨姆伊蚊亦可参与该病毒的传播。     

Soluble Guanylate Cyclase α1–Deficient Mice: A Novel Murine Model for Primary Open Angle Glaucoma

Primary open angle glaucoma (POAG) is a leading cause of blindness worldwide. The molecular signaling involved in the pathogenesis of POAG remains unknown. Here, we report that mice lacking the α₁ subunit of the nitric oxide receptor soluble guanylate cyclase represent a novel and translatable animal model of POAG, characterized by thinning of the retinal nerve fiber layer and loss of optic nerve axons in the context of an open iridocorneal angle. The optic neuropathy associated with soluble guanylate cyclase α₁–deficiency was accompanied by modestly increased intraocular pressure and retinal vascular dysfunction. Moreover, data from a candidate gene association study suggests that a variant in the locus containing the genes encoding for the α₁ and β₁ subunits of soluble guanylate cyclase is associated with POAG in patients presenting with initial paracentral vision loss, a disease subtype thought to be associated with vascular dysregulation. These findings provide new insights into the pathogenesis and genetics of POAG and suggest new therapeutic strategies for POAG.     

Mutation-induced blocker permeability and multiion block of the CFTR chloride channel pore

Chloride permeation through the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel is blocked by a broad range of anions that bind tightly within the pore. Here we show that the divalent anion Pt(NO2)42- acts as an impermeant voltage-dependent blocker of the CFTR pore when added to the intracellular face of excised membrane patches. Block was of modest affinity (apparent Kd 556 microM), kinetically fast, and weakened by extracellular Cl- ions. A mutation in the pore region that alters anion selectivity, F337A, but not another mutation at the same site that has no effect on selectivity (F337Y), had a complex effect on channel block by intracellular Pt(NO2)42- ions. Relative to wild-type, block of F337A-CFTR was weakened at depolarized voltages but strengthened at hyperpolarized voltages. Current in the presence of Pt(NO2)42- increased at very negative voltages in F337A but not wild-type or F337Y, apparently due to relief of block by permeation of Pt(NO2)42- ions to the extracellular solution. This "punchthrough" was prevented by extracellular Cl- ions, reminiscent of a "lock-in" effect. Relief of block in F337A by Pt(NO2)42- permeation was only observed for blocker concentrations above 300 microM; as a result, block at very negative voltages showed an anomalous concentration dependence, with an increase in blocker concentration causing a significant weakening of block and an increase in Cl- current. We interpret this effect as reflecting concentration-dependent permeability of Pt(NO2)42- in F337A, an apparent manifestation of an anomalous mole fraction effect. We suggest that the F337A mutation allows intracellular Pt(NO2)42- to enter deeply into the CFTR pore where it interacts with multiple binding sites, and that simultaneous binding of multiple Pt(NO2)42- ions within the pore promotes their permeation to the extracellular solution.     

Locating structures and evolution pathways of reconstructed rutile TiO<Subscript>2</Subscript>(011) using genetic algorithm aided density functional theory calculations

Titanium dioxide (TiO₂) is an important metal oxide that has been used in many different applications. TiO₂ has also been widely employed as a model system to study basic processes and reactions in surface chemistry and heterogeneous catalysis. In this work, we investigated the (011) surface of rutile TiO₂ by focusing on its reconstruction. Density functional theory calculations aided by a genetic algorithm based optimization scheme were performed to extensively sample the potential energy surfaces of reconstructed rutile TiO₂ structures that obey (2?×?1) periodicity. A lot of stable surface configurations were located, including the global-minimum configuration that was proposed previously. The wide variety of surface structures determined through the calculations performed in this work provide insight into the relationship between the atomic configuration of a surface and its stability. More importantly, several analytical schemes were proposed and tested to gauge the differences and similarities among various surface structures, aiding the construction of the complete pathway for the reconstruction process.