Nucleotide sequence of Rattus norvegiens mitochondrial DNA that includes the genes for tRNAile, tRNAgln and tRNAf-met

The nucleotide sequence of a segment of mtDNA from Rattus norvegiens (rat) which contains the genes for tRNA^ile, tRNA^gl and tRNA^f-met has been determined. A detailed comparison has been made between this sequence and the corresponding sequences of mouse, human and bovine mtDNAs with regard to the primary and secondary structure of the tRNA genes, the regions connecting the tRNA genes, and the regions flanking the tRNA genes which code for the carboxyl terminus of URF-1 and the amino terminus of URF-2. No differences were found in the nucleotide sequences of the genes for tRNA^ile, tRNA^gln and tRNA^f-met in mtDNAs from three different female lines of rats (SASCO-1, SASCO-2 and Wild-UT) that differ by substitutions of 0.8% to 1.8% of their total nucleotides.     

Comparative properties of ferredoxins from a marine and freshwater species of Porphyridium

Ferredoxins were isolated from the freshwater red alga Porphyridium aerugineut, and from Porphyridium cruentum, a related marine species. A sin     

梨小食心虫化学感受蛋白cDNA的克隆、序列分析及原核表达

为了研究梨小食心虫Grapholita molesta化学感受蛋白（chemosensory proteins, CSPs）在化学感受系统中的作用, 本研究利用RT-PCR和RACE技术克隆到一条梨小食心虫化学感受蛋白的全长cDNA序列, 命名为GmolCSP （GenBank 登录号： JQ821389）。序列分析表明, GmolCSP开放阅读框序列为384 bp, 编码127个氨基酸残基, 预测N末端含有18个氨基酸组成的信号肽序列, 其成熟蛋白的预测分子量为12.80 kD, 等电点为8.33。该基因编码的氨基酸序列与其他鳞翅目昆虫化学感受蛋白的氨基酸序列具有较高同源性。RT-PCR结果显示, GmolCSP在梨小食心虫成虫触角、 去触角的头、 胸、 腹、 足和翅中都有表达。将GmolCSP重组到表达载体pET-32a中, 转入大肠杆菌Escherichia coli BL21（DE3）进行表达。SDS-PAGE和Western 印迹检测结果显示, 梨小食心虫化学感受蛋白基因在大肠杆菌中成功地表达出一个分子量约为29 kD的融合蛋白, 与预测的融合蛋白分子量大小一致。本研究结果为进一步研究该蛋白的分子结构和功能奠定了良好基础。     

Genotypic characterization and species identification of Fasciola spp. with implications regarding the isolates infecting goats in Vietnam

Ribosomal RNA sequences (361 or 362 bp) of the second internal transcribed spacer 2 (ITS-2) and a portion of mitochondrial cox1 (423 bp) for Fasciola spp. obtained from specimens collected in indigenous and hybrid goats and sheep in Vietnam were characterized for genotypic status and hybridization/introgression. Alignment of 48 ITS-2 sequences (also those from goats and sheep in this study) indicates that F. gigantica and F. hepatica differ typically from each other at seven sites whereas one of these is a distinguishing deletion (T) at the 327th position in F. gigantica relative to F. hepatica. The isolates from the mountainous goats in the North of Vietnam (Yen Bai province) showed the ITS-2 composition relatively identical to that of F. hepatica. The ITS-2 sequences from populations of Fasciola isolates in goats had probably experienced introgression/hybridization as reported previously in other ruminants and humans. All Vietnamese goat-of-origin specimens had high pairwise percentage of mitochondrial cox1 sequences to F. gigantica (97-100%), and very low identity to F. hepatica (91-93%), suggesting their maternal linkage to be traced to F. gigantica. The presence of hybrid and/or introgressed populations of liver flukes bearing genetic material from both F. hepatica and F. gigantica in the goats/sheep in Vietnam, regardless of indigenous or imported hosts, appears to be the first demonstration from a tropical country.