鸡减蛋综合征病毒(EDSV)基因组右末端结构的分析

从中国发病鸡中分离的鸡减蛋综合征病毒（ＥｇｇＤｒｏｐＳｙｎｄｒｏｍＶｉｒｕｓ,ＥＤＳＶ）弱毒株（ＡＡ－２）,其基因组全长约为３３ｋｂ。用限制性内切酶ＨｉｎｄⅢ水解ＥＤＳＶ全基因组,构建了以ｐＢｌｕｅｓｃｒｉｐｔⅡ（ＫＳ＋）为载体的右末端片段的克隆（约４．２ｋｂ）,对其进行了序列测定和结构分析。该片段全长４１８３个碱基对（ｂｐ）,位于基因组右末端８７．３ｍ．ｕ．－１００ｍ．ｕ．。结果显示,该片段与哺乳动物腺病毒右末端Ｅ４区结构不同,与禽Ⅰ型腺病毒代表株ＣＥＬＯ右末端片段亦无同源性。本文为深入了解ＥＤＳＶ基因组结构特点,ＥＤＳＶ与其他腺病毒基因结构与功能的进化关系和ＥＤＳＶ载体的构建奠定了分子生物学基础     

中药有效成分治疗类风湿关节炎研究进展

中药治疗类风湿性关节炎(RA)有几千年的临床应用历史,积累了丰富的经验.近年来,国内外针对中药复方和单味药的抗RA作用开展了大量的实验研究工作,很多中药的活性成分(组分)和作用机制得到初步阐明,开发出青藤碱注射液、雷公藤多苷片和白芍总苷片等新型RA治疗药物.本文对中药有效成分在治疗RA方面的研究进展进行综述.     

中国大鲵研究进展

中国大鲵是我国特有濒危的两栖物种,是研究生物进化、生物多样性、性别决定分子机制等问题的好材料。近年来,人们对它的研究力度不断加大,著述颇多。本文对大鲵的生态保护、解剖发育、生理生化、遗传进化等方面的近期研究资料进行了整理和回顾,也简要探讨了今后大鲵研究的主要工作,以期为研究者们提供有价值的资料。     

Evidence for a single median fin-fold and tail in the Lower Cambrian vertebrate, Haikouichthys ercaicunensis

In this study, we illustrate an exceptionally well-preserved Haikouichthys ercaicunensis from the Lower Cambrian Chengjiang fauna that displays complete single dorsal, ventral and caudal fins. This 530-million-year old vertebrate is fish-shaped and characterized by a single median fin-fold, which is an essential trait of the initial vertebrate chordates. The radially orientated ray-like structures in its dorsal fin somewhat resemble but are probably not real radials seen in basal vertebrates, such as hagfishes and lampreys. The unique design of primitive fins and fin structures provides additional insights into the early evolution of vertebrates.     

Microbial biosensors: a review

A microbial biosensor is an analytical device which integrates microorganism(s) with a physical transducer to generate a measurable signal proportional to the concentration of analytes. In recent years, a large number of microbial biosensors have been developed for environmental, food, and biomedical applications. Starting with the discussion of various sensing techniques commonly used in microbial biosensing, this review article concentrates on the summarization of the recent progress in the fabrication and application of microbial biosensors based on amperometry, potentiometry, conductometry, voltammetry, microbial fuel cell, fluorescence, bioluminescence, and colorimetry, respectively. Prospective strategies for the design of future microbial biosensors will also be discussed.     

A strategy for fusion expression and preparation of functional glucagon-like peptide-1 (GLP-1) analogue by introducing an enterokinase cleavage site

KGLP-1, a 31-amino acid glucagon-like peptide-1 (GLP-1) analogue, has a great therapeutic potential for anti-diabetes. In this work, a strategy for expression and purification of functional KGLP-1 peptide has been established. KGLP-1 cDNA was fused with glutathione S-transferase (GST), with an enterokinase cleavage site in the fusion junction. The recombinant fusion protein GST–KGLP-1 was affinity purified via the GST-tag, and then digested with enterokinase. The resulting GST part as well as the enzymes were eliminated by ultra-filtration followed by size exclusion chromatograph. The yield of purified KGLP-1 was approximately 12.1 mg/L, with purity of 96.18 %. The recombinant KGLP-1 was shown to have similar bioactivity as native GLP-1 when evaluated in a Chinese hamster ovary cell line expressing a GLP-1 receptor-egfp reporter gene.     

Analysis of variable sites between two complete South China tiger (Panthera tigris amoyensis) mitochondrial genomes

In order to investigate the mitochondrial genome of Panthera tigris amoyensis, two South China tigers (P25 and P27) were analyzed following 15 cymt-specific primer sets. The entire mtDNA sequence was found to be 16,957 bp and 17,001 bp long for P25 and P27 respectively, and this difference in length between P25 and P27 occurred in the number of tandem repeats in the RS-3 segment of the control region. The structural characteristics of complete P. t. amoyensis mitochondrial genomes were also highly similar to those of P. uncia. Additionally, the rate of point mutation was only 0.3% and a total of 59 variable sites between P25 and P27 were found. Out of the 59 variable sites, 6 were located in 6 different tRNA genes, 6 in the 2 rRNA genes, 7 in non-coding regions (one located between tRNA-Asn and tRNA-Tyr and six in the D-loop), and 40 in 10 protein-coding genes. COI held the largest amount of variable sites (9 sites) and Cytb contained the highest variable rate (0.7%) in the complete sequences. Moreover, out of the 40 variable sites located in 10 protein-coding genes, 12 sites were nonsynonymous.     

Myogenesis defect due to Toca-1 knockdown can be suppressed by expression of N-WASP

Skeletal muscle formation is a multistep process involving proliferation, differentiation, alignment and fusion of myoblasts to form myotubes which fuse with additional myoblast to form myofibers. Toca-1 (Transducer of Cdc42-dependent actin assembly), is an adaptor protein which activates N-WASP in conjunction with Cdc42 to facilitate membrane invagination, endocytosis and actin cytoskeleton remodeling. Expression of Toca-1 in mouse primary myoblasts and C2C12 myoblasts was up-regulated on day 1 of differentiation and subsequently down-regulated during differentiation. Knocking down Toca-1 expression in C2C12 cells (Toca-1^KD cells) resulted in a significant decrease in myotube formation and expression of shRNA-resistant Toca-1 in Toca-1^KD cells rescued the myogenic defect, suggesting that the knockdown was specific and Toca-1 is essential for myotube formation. Toca-1^KD cells exhibited elongated spindle-like morphology, expressed myogenic markers (MyoD and MyHC) and localized N-Cadherin at cell periphery similar to control cells suggesting that Toca-1 is not essential for morphological changes or expression of proteins critical for differentiation. Toca-1^KD cells displayed prominent actin fibers suggesting a defect in actin cytoskeleton turnover necessary for cell–cell fusion. Toca-1^KD cells migrated faster than control cells and had a reduced number of vinculin patches similar to N-WASP^KO MEF cells. Transfection of N-WASP-expressing plasmid into Toca-1^KD cells restored myotube formation of Toca-1^KD cells. Thus, our results suggest that Toca-1^KD cells have defects in formation of myotubes probably due to reduced activity of actin cytoskeleton regulators such as N-WASP. This is the first study to identify and characterize the role of Toca-1 in myogenesis.     

Screening of lipid high producing mutant from rhodotorula glutinis by low ion implantation and study on optimization of fermentation medium

In order to obtain lipid producing strain with high-yield, the wild type stain Rhodotorula glutinis was treated by low ion implantation, and optimization of fermentation medium for higher lipid yield was carried out using mutant strain. It was found that the strain had a higher positive mutation rate when the output power was 10 keV and the dose of N⁺ implantation was 80 × 2.6 × 10¹³ ions/cm². Then a high-yield mutant strain D30 was obtained through cid-heating coupling ultrasonic method and lipid yield was 3.10 g/L. Additionally, the surface response method was used to optimize fermentation medium. The three significant factors (glucose, peptone, KH₂PO₄) were optimized using response surface methodology (RSM), and the optimized parameters of fermentation medium were as follows: glucose 73.40 g/L, peptone 1.06 g/L and KH₂PO₄ 3.56 g/L. Finally the fermentation characteristic of high-yield mutation strain D30 was studied, when fermentation time was 10 days, which lipid yield increased to 7.81 g/L. Fatty acid composition of the lipid was determined by GC, and the most represented fatty acids of mutant D30 were C16:0 (11.4 %), C16:1 (5.66 %), C18:1 (49.3 %), and C18:2 (27.0 %).