Identification of the gene (BBS1) most commonly involved in Bardet-Biedl syndrome,a complex human obesity syndrome

Bardet-Biedl syndrome (BBS, OMIM 209900) is a genetic disorder with the primary features of obesity, pigmentary retinopathy, polydactyly, renal malformations, mental retardation and hypogenitalism. Individuals with BBS are also at increased risk for diabetes mellitus, hypertension and congenital heart disease. What was once thought to be a homogeneous autosomal recessive disorder is now known to map to at least six loci: 11q13 (BBS1), 16q21 (BBS2), 3p13 p12 (BBS3), 15q22.3 q23 (BBS4), 2q31 (BBS5) and 20p12 (BBS6). There has been considerable interest in identifying the genes that underlie BBS, because some components of the phenotype are common. Cases of BBS mapping ro BBS6 are caused by mutations in MKKS; mutations in this gene also cause McKusick-Kaufman syndrome (hydrometrocolpos, post-axial polydactyly and congenital heart defects). In addition, we recently used positional cloning to identify the genes underlying BBS2 (ref. 16) and BBS4 (ref. 17). The BBS6 protein has similarity to a Thermoplasma acidophilum chaperonin, whereas BBS2 and BBS4 have no significant similarity to chaperonins. It has recently been suggested that three mutated alleles (two at one locus, and a third at a second locus) may be required for manifestation of BBS (triallelic inheritance). Here we report the identification of the gene BBS1 and show that a missense mutation of this gene is a frequent cause of BBS. In addition, we provide data showing that this common mutation is not involved in triallelic inheritance.     

农药对我国农产品污染的现状及控制对策

我国是化学农药的生产和使用大国,长期以来由于大量的使用,已造成了很大的危害,而且严重影响了人们的身体健康、生态环境和国家战略安全.因此,进一步加大宣传力度、制定相关法律法规、加快研制新型无污染或低污染的农药、研制防治污染的技术及措施是当前及今后努力的方向.     

软件体系结构模型描述的研究

提出一个PetriNet的扩展理论 ,为软件体系结构的描述的正确性提供了一个比较简单但完整的描述的net基础。     

豫西地区土地质量评价

对豫西地区土地质量评价就是对土地的自然属性和社会属性进行全面分析和鉴定，准确地反映土地的自然潜力，为合理地、有效地利用土地资源提供科学依据．     

自然灾害连锁效应分析及综合减灾对策

以2002年江西省发生的自然灾害为例，总结分析了自然灾害间的连锁效应及其特点。提出在全球气候变化的大背景下，以气象灾害为源头形成了一系列自然灾害链的成灾机制，并在此基础上提出了综合防灾减灾对策。     

并发程序切片方法综述

随着实际应用对并发软件需求的不断增加,并发程序的应用越来越广,程序切片的研究不再仅仅局限于顺序程序,并发程序切片的研究也越来越多.但是由于并发程序执行的不确定性,并发程序切片的研究还有许多问题有待解决.文中介绍了当前主要的几种并发程序切片方法及其主要特性,并对这些切片方法进行了比较分析,结果表明并发程序切片的效率和精度都达到理想的目标是不可能的,只能是在两者之间的均衡,最后简要介绍了并发程序切片的应用.     

Amplification of siRNA in Caenorhabditis elegans generates a transgenerational sequence-targeted histone H3 lysine 9 methylation footprint

Exogenous double-stranded RNA (dsRNA) has been shown to exert homology-dependent effects at the level of both target mRNA stability and chromatin structure. Using C. elegans undergoing RNAi as an animal model, we have investigated the generality, scope and longevity of dsRNA-targeted chromatin effects and their dependence on components of the RNAi machinery. Using high-resolution genome-wide chromatin profiling, we found that a diverse set of genes can be induced to acquire locus-specific enrichment of histone H3 lysine 9 trimethylation (H3K9me3), with modification footprints extending several kilobases from the site of dsRNA homology and with locus specificity sufficient to distinguish the targeted locus from the other 20,000 genes in the C. elegans genome. Genetic analysis of the response indicated that factors responsible for secondary siRNA production during RNAi were required for effective targeting of chromatin. Temporal analysis revealed that H3K9me3, once triggered by dsRNA, can be maintained in the absence of dsRNA for at least two generations before being lost. These results implicate dsRNA-triggered chromatin modification in C. elegans as a programmable and locus-specific response defining a metastable state that can persist through generational boundaries.