Polymorphisms of interferon-inducible genes OAS-1 and MxA associated with SARS in the Vietnamese population

We hypothesized that host antiviral genes induced by type I interferons might affect the natural course of severe acute respiratory syndrome (SARS). We analyzed single nucleotide polymorphisms (SNPs) of 2',5'-oligoadenylate synthetase 1 (OAS-1), myxovirus resistance-A (MxA), and double-stranded RNA-dependent protein kinase in 44 Vietnamese SARS patients with 103 controls. The G-allele of non-synonymous A/G SNP in exon 3 of OAS-1 gene showed association with SARS (p=0.0090). The G-allele in exon 3 of OAS-1 and the one in exon 6 were in strong linkage disequilibrium and both of them were associated with SARS infection. The GG genotype and G-allele of G/T SNP at position -88 in the MxA gene promoter were found more frequently in hypoxemic group than in non-hypoxemic group of SARS (p=0.0195). Our findings suggest that polymorphisms of two IFN-inducible genes OAS-1 and MxA might affect susceptibility to the disease and progression of SARS at each level.     

G蛋白偶联受体突变及其相关疾病

G蛋白偶联受体（GPCR）是最大的蛋白质受体超家族之一,参与调节各种生理过程,在信号识别和转导中起重要作用。GPCR的突变及基因多态性将引发各种疾病,目前已经发现有30多种单基因疾病与此相关。介绍了GPCR功能失调的分子基础,在此基础上对一些GPCR突变以及相关疾病做了综逑,并指出了其治疗意义。     

绿洲农业生态经济系统的结构与功能分析──以张掖绿洲为例

通过分析张掖绿洲农业生态经济系统的结构与功能,发现其种群结构单一、产业结构不甚合理、空间结构脆弱,决定了绿洲功能较差,产投比低下的特点,并据此从可持续发展的角度提出了改善绿洲农业生态经济系统结构、提高其功能的对策与建议.     

Highly efficient and inducible DNA excision in transgenic silkworms using the FLP/<Emphasis Type="Italic">FRT</Emphasis> site-specific recombination system

Efficient and inducible recombinase-mediated DNA excision is an optimal technology for automatically deleting unwanted DNA sequences, including selection marker genes. However, this methodology has yet to be established in transgenic silkworms. To achieve efficient and inducible FLP recombinase-mediated DNA excision in transgenic silkworms, one transgenic target strain (TTS) containing an FRT-flanked silkworm cytoplasmic actin 3 gene promoter (A3)-enhanced green fluorescent protein (EGFP) expression cassette, as well as two different types of FLP recombinase expression helper strains were generated. Then, the FLP recombinase was introduced into the TTS silkworms by pre-blastoderm microinjection and sexual hybridization. Successful recombinase-mediated deletion of the A3-EGFP expression cassette was observed in the offspring of the TTS, and the excision efficiencies of the FLP expression vector and FLP mRNA pre-blastoderm microinjection were 2.38 and 13.3 %, respectively. The excision efficiencies resulting from hybridization between the TTS and the helper strain that contained a heat shock protein 70 (Hsp70)-FLP expression cassette ranged from 32.14 to 36.67 % after heat shock treatment, while the excision efficiencies resulting from hybridization between the TTS and the helper strain containing the A3-FLP expression cassette ranged from 97.01 to 100 %. These results demonstrate that the FLP/FRT system can be used to achieve highly efficient and inducible post-integration excision of unwanted DNA sequences in transgenic silkworms in vivo. Our present study will facilitate the development and application of the FLP/FRT system for the functional analysis of unknown genes, and establish the safety of transgenic technologies in the silkworm and other lepidopteran species.     

Cloning and sequencing of a human liver carboxylesterase isoenzyme

A human liver lambda gt11 library was screened with antibodies raised to a purified rat liver carboxylesterase, and several clones were isolated and sequenced. The longest cDNA contained an open reading frame of 507 amino acids that represented 92% of the sequence of a mature carboxylesterase protein. This sequence possessed many structural features that are highly conserved among rabbit and rat liver carboxylesterase proteins, including Ser, His, and Asp residues that comprise the active site, two pairs of Cys residues that may participate in disulfide bond formation, and one Asn-Xxx-Thr site for N-linked carbohydrate addition. When the clone was used to probe human liver genomic DNA that had been digested with various restriction enzymes, many hybridizing bands of differing intensities were observed. The results suggest that the carboxylesterases exist as several isoenzymes in humans, and that they are encoded by multiple genes.     

Horizontal Transfer of Archaeal Genes into the Deinococcaceae: Detection by Molecular and Computer-Based Approaches

Members of the Deinococcaceae (e.g., Thermus, Meiothermus, Deinococcus) contain A/V-ATPases typically found in Archaea or Eukaryotes which were probably acquired by horizontal gene transfer. Two methods were used to quantify the extent to which archaeal or eukaryotic genes have been acquired by this lineage. Screening of a Meiothermus ruber library with probes made against Thermoplasma acidophilum DNA yielded a number of clones which hybridized more strongly than background. One of these contained the prolyl tRNA synthetase (RS) gene. Phylogenetic analysis shows the M. ruber and D. radiodurans prolyl RS to be more closely related to archaeal and eukaryal forms of this gene than to the typical bacterial type. Using a bioinformatics approach, putative open reading frames (ORFs) from the prerelease version of the D. radiodurans genome were screened for genes more closely related to archaeal or eukaryotic genes. Putative ORFs were searched against representative genomes from each of the three domains using automated BLAST. ORFs showing the highest matches against archaeal and eukaryotic genes were collected and ranked. Among the top-ranked hits were the A/V-ATPase catalytic and noncatalytic subunits and the prolyl RS genes. Using phylogenetic methods, ORFs were analyzed and trees assessed for evidence of horizontal gene transfer. Of the 45 genes examined, 20 showed topologies in which D. radiodurans homologues clearly group with eukaryotic or archaeal homologues, and 17 additional trees were found to show probable evidence of horizontal gene transfer. Compared to the total number of ORFs in the genome, those that can be identified as having been acquired from Archaea or Eukaryotes are relatively few (approximately 1%), suggesting that interdomain transfer is rare.     

Molecular genetic characterization of rice seed lipoxygenase 3 and assessment of its effects on seed longevity

Lipoxygenases (LOXs) are enzymes involved in lipid peroxidation. Here we reported the identification, molecular and functional characterization of the gene encoding rice (Oryza sativa L.) seed LOX3 (sLOX3). Via a map-based cloning strategy we identified Os03g0700400 as the candidate gene encoding sLOX3. Further functional complementary test and biochemical characterization of the recombinant Os03g0700400 protein verified the identification. The sLOX3 gene was highly expressed in roots, moderately in embryos and very weakly in leaves, leaf sheaths and stems. Transient expression experiment (in rice protoplasts) and subsequent laser confocal microscopic analysis demonstrated that the sLOX3 protein was localized into the cytosol. We next showed that overexpression of sLOX3 in a japonica sLOX3-normal rice cultivar, Wuyunjing 7 accelerated the decrease of seed germination ability when the seeds were routinely stored, which demonstrated that sLOX3 had a negative effect on seed longevity (storability). Meanwhile, an increased occurrence of embryo decay was observed in the same transgenic seeds, suggesting that sLOX3 might negatively affect seed longevity by facilitating colonization of particular seed pathogens. Our result forwarded the understanding of the effects of 9-LOX on rice seed longevity.     

心肌细胞／胶原复合体移植心梗大鼠梗死周边区的电偶联网络变化

目的应用免疫组化技术和电生理技术记录心肌细胞／胶原复合体对心梗大鼠梗死周边区的有效不应期（ERP）及缝隙连接蛋白43（Cx43）改变,探讨梗死周边区的电偶联网络变化。方法将成年SD大鼠随机分组：假手术组、模型组、移植组。后2组制作心肌梗死动物模型,假手术组仅开胸,不结扎冠状动脉,移植组移植心肌细胞与胶原材料复合组织。结果①左室ERP变化：与假手术组相比,心梗组梗死周边区ERP显著延长（P〈0．01）;移植组梗死周边区ERP延长,但较心梗阻ERP缩短,差异无显著性（P〉0．01）。②Cx43免疫组化结果：移植组Cx43阳性蛋白表达高于心梗组。结论移植的心肌细胞／胶原复合体移植可改善大鼠心肌梗死周边区缝隙连接电偶联网络,进而调控心肌细胞／胶原复合体与宿主心肌同步收缩。