Genome Sequence and Comparative Genomics Analysis of a Vibrio cholerae O1 Strain Isolated from a Cholera Patient in Malaysia

The genome sequence analysis of a clinical Vibrio cholerae VC35 strain from an outbreak case in Malaysia indicates multiple genes involved in host adaptation and a novel Na⁺-driven multidrug efflux pump-coding gene in the genome of Vibrio cholerae with the highest similarity to VMA_001754 of Vibrio mimicus VMA223.     

臭参中挥发性臭味的化学成分

臭参(Codonopsis sp.)俗称臭药、云南参、臭党参等,系桔梗科党参属云南特有植物种,种名待分类学家鉴定。其根具有特殊臭味,民间作为廉价滋补佳品,和肉、蛋一起煮食,具有补中益气,生津之功效。同属许多植物如党参(C.pilosula Nannf)、川党参(C.tangshan Oliv.)等的根,均为著名中药,但都没有臭参那种臭味。该植物的化学成分未见报道。为了解臭参植物的药用价值以及同党参、川党参等的相互关系,我们首先对臭参的挥发性臭味化学成分作了气相色谱-质谱法分析,现将结果简要报告如下。     

广西北部罗汉果根结线虫病研究

罗汉果根结线虫是罗汉果的一个重要病害。在室内盆栽接种条件下,该线虫年发生6代。本文叙述了线虫的生物学及其寄主植物。防治试验结果表明。穴施灭克磷等是有效的。土壤翻晒也能消灭大部分土中线虫,病薯用热处理也有很好的效果。     

De novo purine nucleotide biosynthesis: cloning of human and avian cDNAs encoding the trifunctional glycinamide ribonucleotide synthetase-aminoimidazole ribonucleotide synthetase-glycinamide ribonucleotide transformylase by functional complementation in E. coli.

The trifunctional enzyme encoding glycinamide ribonucleotide synthetase (GARS)-aminoimidazole ribonucleotide synthetase (AIRS)-glycinamide ribonucleotide transformylase (GART) was cloned by functional complementation of an E. coli mutant using an avian liver cDNA expression library. In E. coli, genes encoding these separate activities (purD, purM, and purN, respectively) produce three proteins. The avian cDNA, in contrast, encodes a single polypeptide with all three enzyme activities. Using the avian DNA as a probe, a cDNA encoding the complete coding sequence of the trifunctional human enzyme was also isolated and sequenced. The deduced amino acid sequence of the human and avian polyproteins show extensive sequence homologies to the bacterial purD, purM, and purN encoded proteins. Avian and human liver RNAs appear to encode both a trifunctional enzyme (G-ARS-AIRS-GART) as well as an RNA which encodes only GARS. The trifunctional protein has been implicated in the pathology of Downs Syndrome and molecular tools are now available to explore this hypothesis. Initial efforts to compare the expression of GARS-AIRS-GART between a normal fibroblast cell line and a Downs Syndrome cell line indicate that the levels of RNA are similar.     

Flavonoids as superoxide scavengers and antioxidants

The superoxide anions scavenging activity and antioxidation of seven flavonoids--quercetin, rutin, morin, acacetin, hispidulin, hesperidin, and naringin--were studied. The superoxide anions were generated in a phenazin methosulphate-NADH system and were assayed by reduction of nitroblue tetrazolium. The scavenging activity ranked: rutin was the strongest, and quercetin and naringin the second, while morin and hispidulin were very weak. The concentration values yielding 50% inhibition of lipid peroxidation in mouse liver homogenate were in order of 10(-6) M for quercetin, rutin, and morin; and of 10(-5) M for acacetin and hispidulin, while naringin and hesperidin had no antioxidative action. In comparison with the antioxidative and scavenging activities of flavonoids, there are no correlations.     

甘肃东乡几种早中新世哺乳动物化石

本文记述了在甘肃东乡椒子沟发现的几种早中新世哺乳动物化石:Gomphotherium sp、Dzungariotheriura orgosense、Rhinocerotidae gen. indet.和Paraentelodon macrognathus sp. nov.,着重讨论了全北区猪齿兽类的系统关系。根据化石的性质判断,东乡椒子沟化石点的地质时代应与欧洲Burdigalian早期,亦即MN_3相当或稍早。笔者将原定为上新世临夏组的第一、二岩性段划出,命名为椒子沟组,其时代为早中新世。     

人体小卫星DNA探针的制备

根据人体小卫星DNA核心顺序,化学合成长23碱基寡核苷酸探针,筛选人体基因组文库,旨在获得能用作遗传分析探针的小卫星顺序。结果得到15个含小卫星的阳性重组子。随机取其一(C_(35.9))作探针,试做群体分析。所有个体均可检出多条杂交带。其中某些带具有多态性。在一定检测条件下,检出的DNA图谱在有限的个体内具有个体特异性。结果表明筛选文库得到的小卫星顺序可用于小卫星多态性的检测。其它小卫星探针的筛选和应用性研究正在进行。