Isolation and Characterization of 2'-amino-modified RNA Aptamers for Human TNFα

Human tumor necrosis factor a (hTNFa), a pleiotropic cytokine with activities ranging from host defense mechanisms in infection and injury to severe toxicity in septic shock or other related diseases, is a promising target for drug screening. Using the SELEX (systematic evolution of ligands by exponential enrichment) process, we isolated oligonucleotide ligands (aptamers) with high affinities for hTNFa. Aptamers were selected from a starting pool of 40 randomized sequences composed of about 1015 RNA molecules. Representative aptamers were truncated to the minimal length with high affinity for hTNFa and were further modified by replacement of 2'-OH with 2'-F and 2'-NH2 at all ribopurine positions. These modified RNA aptamers were resistant to nuclease. The specificity of these aptamers for hTNFa was confirmed, and their activity to inhibit the cytotoxicity of hTNFa on mouse L929 cells was determined. Results demonstrated that four 2'-NH2-modified aptamers bound to hTNFa with high affinity and blocked the     

不同干旱胁迫下欧李光合及叶绿素荧光参数的响应

采用人为控制土壤含水量的方法对欧李进行轻度和重度干旱的处理,测定叶片的气体交换和叶绿素荧光参数的日变化。结果表明,干旱胁迫下欧李叶片净光合速率、蒸腾速率、水分利用效率、气孔导度、PSII最大光化学效率、光化学量子效率显著下降,但胞间CO2浓度、非光化学猝灭系数以及叶黄素循脱环氧化状态（Z＋0.5A）/（V＋A＋Z）和Z含量升高。两干旱处理植株的影响程度存在差异。这表明在长时间干旱条件下,欧李叶片光合作用的降低受到气孔与非气孔因素的双重影响,叶黄素循环的启动增加了胁迫条件下的热耗散能力以保护光合机构免受干旱胁迫的进一步伤害。     

柑橘体细胞杂种砧木对脐橙幼树生长及根和叶中抗氧化酶系活性的影响

以体细胞杂种红橘 枳、红橘 粗柠檬和有性杂种Troyer枳橙、Swingle枳柚作砧木的脐橙二年生嫁接苗为试材,于盆栽条件下研究砧木对苗木生长及根和叶中抗氧化酶系活性影响的结果表明,红橘 枳的生长势和花量明显强于和大于其它砧木,红橘 粗柠檬的生长和花量表现介于两种有性杂种之间;砧木不影响叶片中可溶性蛋白含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性年动态变化特征.4、6、8月,叶中POD活性高低分别与各次新梢生长量和树冠体积(8月)大小呈负相关;12月,根系与叶片的SOD和POD活性分别呈正相关,根系可溶性蛋白含量和根系CAT活性呈正相关.     

鸡减蛋综合征病毒（EDSV—76）末端前体蛋白的基因结构分析

从中国发病鸡群中分离的鸡减蛋综合征病毒弱毒株ＡＡ－２,经常规方法提取其病毒核酸后,组建了完整的限制性内切酶ＰｓｔＩ及ＨｉｎｇⅢ水解片段的基因文库,并对其中ＨｉｎｄⅢ,－ＳａｃⅠ进行了序列测定。同源比较分析证明：其Ｌ链含编码病毒末端前体蛋白,容量为５８０个氨基酸残基的开放读码框架。     

Exome Sequencing Identifies Mutations in CCDC114 as a Cause of Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, autosomal-recessive disorder, characterized by oto-sino-pulmonary disease and situs abnormalities. PCD-causing mutations have been identified in 14 genes, but they collectively account for only ∼60% of all PCD. To identify mutations that cause PCD, we performed exome sequencing on six unrelated probands with ciliary outer dynein arm (ODA) defects. Mutations in CCDC114, an ortholog of the Chlamydomonas reinhardtii motility gene DCC2, were identified in a family with two affected siblings. Sanger sequencing of 67 additional individuals with PCD with ODA defects from 58 families revealed CCDC114 mutations in 4 individuals in 3 families. All 6 individuals with CCDC114 mutations had characteristic oto-sino-pulmonary disease, but none had situs abnormalities. In the remaining 5 individuals with PCD who underwent exome sequencing, we identified mutations in two genes (DNAI2, DNAH5) known to cause PCD, including an Ashkenazi Jewish founder mutation in DNAI2. These results revealed that mutations in CCDC114 are a cause of ciliary dysmotility and PCD and further demonstrate the utility of exome sequencing to identify genetic causes in heterogeneous recessive disorders.     

Meta-analysis of Gene-Level Associations for Rare Variants Based on Single-Variant Statistics

Meta-analysis of genome-wide association studies (GWASs) has led to the discoveries of many common variants associated with complex human diseases. There is a growing recognition that identifying “causal” rare variants also requires large-scale meta-analysis. The fact that association tests with rare variants are performed at the gene level rather than at the variant level poses unprecedented challenges in the meta-analysis. First, different studies may adopt different gene-level tests, so the results are not compatible. Second, gene-level tests require multivariate statistics (i.e., components of the test statistic and their covariance matrix), which are difficult to obtain. To overcome these challenges, we propose to perform gene-level tests for rare variants by combining the results of single-variant analysis (i.e., p values of association tests and effect estimates) from participating studies. This simple strategy is possible because of an insight that multivariate statistics can be recovered from single-variant statistics, together with the correlation matrix of the single-variant test statistics, which can be estimated from one of the participating studies or from a publicly available database. We show both theoretically and numerically that the proposed meta-analysis approach provides accurate control of the type I error and is as powerful as joint analysis of individual participant data. This approach accommodates any disease phenotype and any study design and produces all commonly used gene-level tests. An application to the GWAS summary results of the Genetic Investigation of ANthropometric Traits (GIANT) consortium reveals rare and low-frequency variants associated with human height. The relevant software is freely available.     

Evidence for a Language Quantitative Trait Locus on Chromosome 7q in Multiplex Autism Families

Autism is a syndrome characterized by deficits in language and social skills and by repetitive behaviors. We hypothesized that potential quantitative trait loci (QTLs) related to component autism endophenotypes might underlie putative or significant regions of autism linkage. We performed nonparametric multipoint linkage analyses, in 152 families from the Autism Genetic Resource Exchange, focusing on three traits derived from the Autism Diagnostic Interview: "age at first word," "age at first phrase," and a composite measure of "repetitive and stereotyped behavior." Families were genotyped for 335 markers, and multipoint sib pair linkage analyses were conducted. Using nonparametric multipoint linkage analysis, we found the strongest QTL evidence for age at first word on chromosome 7q (nonparametric test statistic [Z] 2.98; P=.001), and subsequent linkage analyses of additional markers and association analyses in the same region supported the initial result (Z=2.85, P=.002; chi(2)=18.84, df 8, P=.016). Moreover, the peak fine-mapping result for repetitive behavior (Z=2.48; P=.007) localized to a region overlapping this language QTL. The putative autism-susceptibility locus on chromosome 7 may be the result of separate QTLs for the language and repetitive or stereotyped behavior deficits that are associated with the disorder.     

Mutation analysis of the coding sequence of the MECP2 gene in infantile autism

Mutations in the coding region of the methyl-CpG-binding protein 2 ( MECP2) gene cause Rett syndrome and have also been reported in a number of X-linked mental retardation syndromes. Furthermore, such mutations have recently been described in a few autistic patients. In this study, a large sample of individuals with autism was screened in order to elucidate systematically whether specific mutations in MECP2 play a role in autism. The mutation analysis of the coding sequence of the gene was performed by denaturing high-pressure liquid chromatography and direct sequencing. Taken together, 14 sequence variants were identified in 152 autistic patients from 134 German families and 50 unrelated patients from the International Molecular Genetic Study of Autism Consortium affected relative-pair sample. Eleven of these variants were excluded for having an aetiological role as they were either silent mutations, did not cosegregate with autism in the pedigrees of the patients or represented known polymorphisms. The relevance of the three remaining mutations towards the aetiology of autism could not be ruled out, although they were not localised within functional domains of MeCP2 and may be rare polymorphisms. Taking into account the large size of our sample, we conclude that mutations in the coding region of MECP2 do not play a major role in autism susceptibility. Therefore, infantile autism and Rett syndrome probably represent two distinct entities at the molecular genetic level.