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151.
鼠尾草属药用植物资源 总被引:4,自引:0,他引:4
本文介绍了鼠尾草属常用药用植物的地理分布、化学成分、生物学及生态学特征和资源的开发、利用与保护等。 相似文献
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金黄色葡萄球菌(Staphylococcus aureus)是引起食物中毒的重要致病菌。为简化金黄色葡萄球菌复杂的检测方法,并了解舟山市水产品中该致病菌的污染状况,通过比较已公开的3套针对耐热核酸酶编码基因的PCR鉴定体系,根据特异性和灵敏性实验筛选了1套最优的针对金黄色葡萄球菌的PCR鉴定体系。基于这一体系和国家规定的标准方法,对舟山市水产品加工厂各个环节采集的120份样品中金黄色葡萄球菌的污染状况进行了调查。结果显示,120份样品中金黄色葡萄球菌的检出率为8.3%,PCR检测方法与国标法检出阳性率比较无显著差异,而且集中在原料和环境这两个环节检出金黄色葡萄球菌,在半成品和成品中却未检测到。由此,可以认为舟山市水产品加工厂的原料和环境中存在着一定的安全隐患,而成品相对较为安全。 相似文献
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Li BS Tan HL Wang DC Deng XL Chen JD Zhong HJ Ke BX Ke CW Kan B 《Current microbiology》2011,62(3):950-955
To enhance the understanding of epidemiological impact of environmental Vibrio cholerae O139 strains, we characterized 10 clinical and 20 environmental isolates collected from human clinical samples and Pear River estuary during 2006 to 2008. Isolates were tested by PCR for eight virulence genes: cholera toxin (ctxA), zonula occludens toxin (zot), accessory cholera enterotoxin (ace), hemolysin (hlyA), NAG-specific heat-stable toxin (st), toxin-coregulated pilus (tcpA), outer membrane protein (ompU), and regulatory protein genes (tcpI). Genetic relatedness was assessed by pulsed-field gel electrophoresis (PFGE), and antibiotic susceptibility was determined using disk diffusion. Seven of eight virulence markers were detected in six clinical isolates and one environmental isolate. One clinical and one environmental isolate were positive for six virulence markers. 60% clinical isolates showed multi-drug resistance to tetracycline (TET), Nalidixic acid (NAL), chloramphenicol (CHL), and ampicillin (AMP), 70% were resistant to Trimethoprim + Sulfamethoxazole (SXT), while only 35% environmental strains were resistant to SXT. PFGE analysis revealed that the isolates in this study were formed three clusters. Cluster III was more related to strains from diarrheal patients than the strains in other clusters. Different from the clinical strains, most environmental strains lacked CTX and TCP gene clusters. Most environmental strains possess a single resistance profile, while most clinical isolates show multidrug resistant. PFGE analysis indicated the cluster III has more possibility to become a potential pathogenic clonal cluster. 相似文献
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Xin‐Hua Ma Zhi‐Biao Wang Lei Zhang Wei Li Cui‐Min Deng Tian‐Hua Zhong Guang‐Yu Li Wei‐Ming Zheng Yong‐Hong Zhang 《化学与生物多样性》2017,14(5)
One new ent‐kaurane diterpenoid, 11β,16α‐dihydroxy‐ent‐kauran‐19‐oic acid ( 1 ), together with eight known analogues 2 – 9 were isolated from the aerial parts of Wedelia prostrata. One of the acidic diterpenoids, kaurenoic acid ( 3 ), was converted to seven derivatives, 10 – 16 . All compounds were evaluated for their cytotoxic activity in vitro against human leukemia (K562), liver (HepG‐2), and stomach (SGC‐7901) cancer cell lines. Only four kaurenoic acid derivatives, 13 – 16 , with 15‐keto and substitutions at C(19) position, exhibited notable cytotoxic activities on these tumor cell lines with IC50 value ranging from 0.05 to 3.71 μm . Compounds 10 – 12 , with oxime on C(15) showed moderate inhibitory effects and compounds 1 – 9 showed no cytotoxicities on them. Structure–activity relationships were also discussed based on the experimental data obtained. The known derivative, 15‐oxokaurenoic acid 4‐piperdin‐1‐ylbutyl ester ( 17 ), induced typical apoptotic cell death in colon SW480 cells upon evaluation of the apoptosis‐inducing activity by flow‐cytometric analysis. 相似文献
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To study the roles of translational accuracy, translational efficiency, and the Hill-Robertson effect in codon usage bias, we studied the intragenic spatial distribution of synonymous codon usage bias in four prokaryotic (Escherichia coli, Bacillus subtilis, Sulfolobus tokodaii, and Thermotoga maritima) and two eukaryotic (Saccharomyces cerevisiae and Drosophila melanogaster) genomes. We generated supersequences at each codon position across genes in a genome and computed the overall bias at each codon position. By quantitatively evaluating the trend of spatial patterns using isotonic regression, we show that in yeast and prokaryotic genomes, codon usage bias increases along translational direction, which is consistent with purifying selection against nonsense errors. Fruit fly genes show a nearly symmetric M-shaped spatial pattern of codon usage bias, with less bias in the middle and both ends. The low codon usage bias in the middle region is best explained by interference (the Hill-Robertson effect) between selections at different codon positions. In both yeast and fruit fly, spatial patterns of codon usage bias are characteristically different from patterns of GC-content variations. Effect of expression level on the strength of codon usage bias is more conspicuous than its effect on the shape of the spatial distribution. 相似文献
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人类肠道菌群能够产生多种代谢产物或与人体相互作用产生肠道菌群-宿主共代谢物,显著影响人体各大系统的生理功能。当人体健康状态以及肠道菌群发生变化时,肠道代谢物的种类和含量也会相应受到影响,因此肠道菌群代谢产物具有作为疾病诊断指针的巨大潜力。本文总结了常见的几类肠道微生物代谢产物,包括糖类、胆碱代谢物、脂质、氨基酸与肽类、维生素、胆汁酸、短链脂肪酸、酚、苯甲酰基和苯基衍生物等,及其在不同疾病状态下的作用机理,以期更好地理解肠道菌群、代谢产物和疾病之间的相关性,为疾病的预防、诊断和治疗提供新的靶点。 相似文献