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QSAR models represent the relationship of biological activity with either physicochemical parameters or structural indices. QSAR study was performed on some arylpiperazines as 5-HT(1A)/alpha(1)-adrenergic receptor antagonists using E-state indices to identify the pharmacophoric requirements. It was found that some of the atoms played important roles to both activities and some played important role in selectivity of compound to the 5-HT(1A) antagonistic activity. The presence of COONHPr group at the ortho-position of the phenyl ring might be disadvantageous and Br at meta-position might be conducive to the activity. COOPr at the ortho-position might be disfavored the adrenergic alpha(1)-antagonistic activity, thus increase the selectivity.  相似文献   
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Microscopic examinations have convinced microbial ecologists that the culturable microbes recovered from environmental samples represent a tiny proportion of the extant microbiota. Methods for recovery and enzymatic amplification of nucleic acids from environmental samples have shown that a huge diversity existsin situ, far exceeding any expectations which were based on direct microscopy. It is now theoretically possible to extract, amplify and sequence all the nucleic acids from a community and thereby gain a comprehensive measure of the diversity as well as some insights into the phylogeny of the various elements within this community. Unfortunately, this analysis becomes economically prohibitive if applied to the multitude of niches in a single biome let alone to a diverse set of environments. It is also difficult to utilize PCR amplification on nucleic acids from some biomes because of coextracting enzymatic inhibitors. Signature biomarker analysis which potentially combines gene probe and lipid analysis on the same sample, can serve as a complement to massive environmental genome analysis in providing quantitative comparisons between microniches in the biome under study. This analysis can also give indications of the magnitude of differences in biodiversity in the blome as well as provide insight into the phenotypic activities of each community in a rapid and cost-effective manner. Applications of signature lipid biomarker analysis to define quantitatively the microbial viable biomass of portions of an Eastern USA deciduous forest, are presented.  相似文献   
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