Trace element stimulation of keratin (Hair) degradation by oral keratinolytic microflora

Zusammenfassung Nach der Proteolyse-Chelationstheorie der Zahnkaries werden organische und anorganische Bestandteile des Zahnschmelzes mehr oder weniger gleichzeitig abgebaut. Die Ergebnisse dieser Untersuchungen zeigen, dass 1. mineralische Bestandteile des Schmelzes die mikrobiologische Zersetzung des Keratins fördern und dass 2. die enzymatische Zersetzung des Keratins Stoffe entwickelt, welche die Apatitauflösung mittels Chelation fördern.

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This investigation was supported in part by a research grant D-182(C) from the National Institute of Dental Research of the National Institutes of Health, United States Public Health Service.     

人类乙型肝炎样病毒核心蛋白中第7位疏水性氨基酸重复肚段区域的突变可以抑制病毒核衣壳的组装

人类乙型肝炎病毒的核衣壳由核心蛋白的二聚体所组成．但是,核心蛋白亚单位与亚单位之间相互作用的机制至今尚不清楚．研究发现,在人类乙型肝炎样病毒──土拨鼠肝炎病毒（WHV）核心蛋白的氨基端,存在着4个保守的疏水氨基酸残基（氨基酸位置101～102）．它们分别是亮氨酸101,亮氨酸108,缬氨酸115和苯丙氨酸122．这4个疏水氨基酸残基以每隔6个氨基酸残基而重复出现1次．它们被称为“第7位疏水性氨基酸重复肽段（hhr）”．由于蛋白质中的疏水键往往在蛋白质的相互作用中起重要作用,因此就在培养细胞系统中研究WHV核心蛋白的hhr区域在…     

Coral communities are regionally enriched along an oceanic biodiversity gradient

Ecological communities are influenced by processes operating at multiple scales. Thus, a better understanding of how broad- as well as local-scale processes affect species diversity and richness is increasingly becoming a central focus in modern community ecology. Here, in a study of unprecedented geographical scope, we show significant regional and local variation in the species richness of coral assemblages across an oceanic biodiversity gradient. The gradient that we sampled extends 10,000 km eastwards from the world's richest coral biodiversity hotspot in the central Indo-Pacific. Local richness and the size of regional species pools decline significantly across 15 islands spanning the gradient. In addition, richness declines across three adjacent habitats (reef slopes, crests and flats). In each habitat, a highly consistent linear relationship between local and regional species richness indicates strong regional enrichment. Thus, even on the most diverse coral reefs in the world, local coral assemblages are profoundly affected by regional-scale processes. Understanding these historical and biogeographical influences is essential for the effective management and preservation of these endangered communities.     

Two independent alleles at 6q23 associated with risk of rheumatoid arthritis

To identify susceptibility alleles associated with rheumatoid arthritis, we genotyped 397 individuals with rheumatoid arthritis for 116,204 SNPs and carried out an association analysis in comparison to publicly available genotype data for 1,211 related individuals from the Framingham Heart Study. After evaluating and adjusting for technical and population biases, we identified a SNP at 6q23 (rs10499194, approximately 150 kb from TNFAIP3 and OLIG3) that was reproducibly associated with rheumatoid arthritis both in the genome-wide association (GWA) scan and in 5,541 additional case-control samples (P = 10(-3), GWA scan; P < 10(-6), replication; P = 10(-9), combined). In a concurrent study, the Wellcome Trust Case Control Consortium (WTCCC) has reported strong association of rheumatoid arthritis susceptibility to a different SNP located 3.8 kb from rs10499194 (rs6920220; P = 5 x 10(-6) in WTCCC). We show that these two SNP associations are statistically independent, are each reproducible in the comparison of our data and WTCCC data, and define risk and protective haplotypes for rheumatoid arthritis at 6q23.     

人类乙型肝炎样病毒Pre—S1包膜蛋白的一个特定区域为乙肝病毒形成所必需

土拨鼠肝炎病毒（WHV）是一种哺乳类动物的肝炎病毒．这种病毒在结构和抗原怕与人类乙型肝炎病毒（HBV）非常相似．以往的研究报告指出,在一种称为鸭乙型肝炎病毒（DHBV）的Pre－S包膜蛋白中,含有一个特定区域．这一区域由天冬氨酸－天冬氨酸－脯氨酸－亮氨酸－亮氨酸（DDPLL）5个氨基酸残基所组成．已发现,这一区域在像DHBV这一类禽类乙肝病毒的病毒装配和分泌时所必需的（LenhoffR,SummersJ．JVirol,1994,68：4565～4571）．在WHV的Pre－S包胰蛋白中第201个氨基酸到第205个氨基酸所包含的顺序,甘氨酸－天冬氨酸－脯氨…