The molecular characterization of RNA segment S9 of grass carp hemorrhage virus (GCHV), an aquareovirus

Although reovirus infection is one of the major virus diseases of grass carp in China, the available knowledge on the structure and function of genes and proteins of the virus is limited. The complete sequence of the S9 genome segment of grass carp hemorrhage virus (GCHV) was determined. The segment consists of 1130 nucleotides and has a large open reading frame (ORF) encoding a protein of 352 amino acids with predicted molecular mass of 37.7 kDa. Amino acid sequence comparison revealed that the deduced protein encoded by GCHV S9 is closely related to the sigma NS proteins of mammalian reovirus (MRV) and avian reovirus (ARV). Secondary structure analysis displayed that the form of alpha -helices (40.1%) and beta -sheets (49.4%) are the richest two contents in the protein encoded by S9, and this protein is predicted to be a nonstructural protein. (C) 2001 Elsevier Science B.V. All rights reserved.

餐洗剂对小鼠骨髓细胞SCE形成和Salmonella typhimurium基因回复突变的 影响

研究了四种餐洗剂及其主要成分LABS、Dispersol D、Alkanolamide的潜在 诱变活性。结果 表明四种牌号餐洗剂在高浓度时能诱发SCE形成。除TL牌餐洗剂 加入S9代谢激活系统后未见 诱变作用外, 其他三种餐洗剂和三种主要成分都表 现出致HisG46和HisD3052基因回复突变的能力。表3参16

表面活性类物质对SCE形成和基因突变的影响

本研究采用Salmonella typhimurium基因回复突变测试和小鼠骨髓细胞SCE分析方法，从分子水平和染色体水平对国产四种餐洗剂及其三种主要成分LABS, Dispersol D和Alkanolamide进行了潜在性诱变活性的测试。结果表明在没有代谢激活剂的情况下，四种餐洗剂和其主要成分LABS, Dispersol D均能诱发HisD3052和HisG46菌株的基因突变，与阴性对照物相比，显著性明显，Alkanolamide能致HisD3052菌株的回复突变，但对HisD46位点没有致突变效应，加入体外代谢激活物质S9后，除TL牌餐洗剂未见诱变作用处，其他三种牌号的餐洗剂及Dispersol D和LABS仍能使STY回复突变菌落的数目增加，与阴性对照物相比，差异显著，而Alkanolamide在受谢转化激活后，表现出同时能致两个菌株突变的作用，但这四种牌号的餐洗剂和三种主要成分在低于一定浓度，即相当于人日常用量时，无论有无体外激活系统，均无诱导STY基因回复突变的现象出现，SCE分析结果与溶剂对照相比，表明四种餐洗剂都具有诱发小鼠骨髓细胞SCE形成的能力。本文还观察了四种洗涤剂对细胞的性，发现小鼠经高剂灌胃后，骨髓细胞增殖速度降低。同样，四种牌号的餐洗剂和其主要成分Dispersol D，LABS在高剂量时使细菌菌落生长异常，出现针尖点状小菌落，或自然回复突变率减少，此时，本文还讨论了不同诱变效应之间可能存在的关系。

Slow isocharged sequence ions with helium collisions: Projectile core dependence

The collisions of the isocharged sequence ions of q=6 (C6+, N6+, O6+, F6+, Ne6+, Ar6+, and Ca6+), q=7 (F7+, Ne7+, S7+, Ar7+, and Ca7+), q=8 (F8+, Ne8+, Ar8+, and Ca8+), q=9 (F9+, Ne9+, Si9+, S9+, Ar9+, and Ca9+) and q=11 (Si11+, Ar11+, and Ca11+) with helium at the same velocities were investigated. The cross-section ratios of the double-electron transfer (DET) to the single-electron capture (SEC) sigma(DET)/sigma(SEC) and the true double-electron capture (TDC) to the double-electron transfer sigma(TDC)/sigma(DET) were measured. It shows that for different ions in an isocharged sequence, the experimental cross-section ratio sigma(DET)/sigma(SEC) varies by a factor of 3. The results confirm that the projectile core is another dominant factor besides the charge state and the collision velocity in slow (0.35-0.49v(0); v(0) denotes the Bohr velocity) highly charged ions (HCIs) with helium collisions. The experimental cross-section ratio sigma(DET)/sigma(SEC) is compared with the extended classical over-barrier model (ECBM) [A. Barany , Nucl. Instrum. Methods Phys. Res. B 9, 397 (1985)], the molecular Coulombic barrier model (MCBM) [A. Niehaus, J. Phys. B 19, 2925 (1986)], and the semiempirical scaling laws (SSL) [N. Selberg , Phys. Rev. A 54, 4127 (1996)]. It also shows that the projectile core properties affect the initial capture probabilities as well as the subsequent relaxation of the projectiles. The experimental cross-section ratio sigma(TDC)/sigma(DET) for those lower isocharged sequences is dramatically affected by the projectile core structure, while for those sufficiently highly isocharged sequences, the autoionization always dominates, hence the cross-section ratio sigma(TDC)/sigma(DET) is always small.

内蒙古砷中毒和台湾乌脚病病区井水中腐植酸性质的比较

为了探讨地下水性质与台湾乌脚病区相似的内蒙古砷中毒病区今后是否会出现乌脚病。方法：用AAS（原子吸收光谱），ICP－MS（等离子体发射光谱－质谱），红外，荧光和TLS（Total luminescence spectroscopy)光谱分析了两地水样的理化特征，元素组成，荧光强度和各种谱学特征，还对两病区水样中提取的腐植酸样品进行了Ames试验和脂质过氧化反应的试验。结果：发病内蒙砷中毒病区地下水属于HCO3－Na和HCO3－Cl-Na型，平均pH值为7．91，为弱碱性还原环境，两地水样中的砷浓度和腐植酸的荧光强度均较高，荧光强度与砷浓度，pH值和总溶解固体（TDS）呈正相关关系，且两地水中腐植酸的荧光光谱性质也相似，但是它们的红外光谱和TLS光谱有差异，这些差异在生物学效应上表现为：内蒙腐植酸具有较强的引发脂质过氧化反应的能力，而台湾腐植酸对TA98（±S9）菌株具有致突变作用。结论：内蒙砷病区5年内不太可能出现乌脚病。