Cloning and expression of the gene for a fibronectin-binding protein from Staphylococcus aureus.

The gene encoding the fibronectin-binding protein (FNBP) from Staphylococcus aureus strain 8325-4 was isolated from a gene bank in pBR322. The original clone, containing a 6.5-kb insert, gave a functional product present in the periplasm of Escherichia coli. Analysis of polypeptides isolated after affinity chromatography on fibronectin-Sepharose followed by ion-exchange chromatography revealed two gene products, 87 and 165 kd in mol. wt. The amino acid compositions of these two polypeptides and a native FNBP from S. aureus strain Newman were very similar. Antibodies raised against the native FNBP from strain Newman precipitated the 125I-labelled 165-kd polypeptide, and unlabeled 165- and 87-kd polypeptides as well as native FNBP inhibited the immunoprecipitation reactions. The region of the fnbp-gene encoding the fibronectin-binding activity has been identified and subcloned in an expression vector based on the staphylococcal protein A gene. The resulting product in E. coli is an extracellular fusion protein consisting of two IgG-binding domains of protein A followed by a fibronectin-binding region. The fusion protein binds to fibronectin and completely inhibits the binding of fibronectin to intact cells of S. aureus.     

广东哺乳类及两栖类寄生吸虫四新种的记述（吸虫纲：蹲茎科,蛙蠕科）

作者在广东省梅县市发现四个吸虫新种:1.鼠丽色吸虫,新种Reesella ratta sp. nov., 2.后囊蛙蠕吸虫,新种Batrachotrema optstosacca sp. nov., 3.梅县后平睾吸虫,新种Opisthioparorchis meixianensis sp. nov., 4.大卵后平睾吸虫,新种Opisthioparorchis megaloonos sp. nov.,它们分别归隶于蹲茎科Cathaemasiidae及蛙蠕科Bstrachotrematidae。模式标本保存于中山医科大学寄生虫学研究所。     

Expression in Bacillus subtilis of the gene for human urogastrone using synthetic ribosome binding sites

Summary A chemically synthesised gene coding for human urogastrone which was earlier cloned in E. coli (Smith et al. 1982) has now been cloned into expression vectors for Bacillus subtilis Two types of constructs have been made, one giving production of methionylurogastrone and the other giving rise to a methionyl-urogastrone- galactosidase fusion polypeptide facilitating quantification of expression levels.The ribosome binding sites used in the expression plasmids are synthetically made oligonucleotides residing on short restriction fragments to allow easy replacement by other ribosome binding sites.Using shuttle vectors and constitutive promoters from Bacillus phages 105 and SPP1, we were able to detect levels of expression amounting to a few thousand molecules per cell during logarithmic growth in both E. coli and B. subtilis.     

Detection in rabbit sera of blocking antibodies against staphylococcal fibronectin-binding protein by enzyme-linked immunosorbent assay

Antibody titres against fibronectin-binding protein (FnBP) of Staphylococcus aureus were determined in sera from rabbits immunized with staphylococcal whole cells or purified native fibronectin receptor. An ELISA technique for detection of antibody titres blocking the binding of soluble fibronectin to immobilized FnBP was developed. A recombinant staphylococcal FnBP fused to E. coli beta-galactosidase (gal-FnBp) was used as the immobilized antigen in this test. Serum samples from two different rabbits immunized with native fibronectin receptor gave significant blocking titres, whereas the blocking titres of antisera against staphylococcal whole cells were about 4- to 5-fold lower. Using the gal-FnBP fusion protein, the sensitivity for detection of fibronectin by ELISA was also determined. The detection limit is around 5 ng. The findings are discussed with a view to developing an anti-staphylococcal adherence vaccine and quantitating fibronectin in solution.     

我国微茎类吸虫研究:ⅩⅢ.微茎类吸虫成虫结构特征排序

对我国52种微茎类吸虫的18项成虫形态学特征进行主成分分析,结果表明:卵巢位置、子宫延伸位置等7项性状对第一主成分贡献较大,提示描述器官位置的指标是重要的分类依据。52个虫种在前三个主成分上的排序图显示应将其划分成4个亚科。     

23Na NMR study of the effect of organic osmolytes on DNA counterion atmosphere.

The effect of different organic osmolytes on the DNA counterion condensation layer has been investigated by 23Na NMR relaxation measurements. The zwitterionic compounds glycine, beta-alanine, 4-aminobutyric acid, and 6-aminocaproic acid have shown an increasing capacity to decrease the amount of sodium ions in the vicinity of the macromolecule. The experimental data have been correlated with the dielectric constant increase in their corresponding solutions and have been compared with the prediction of counterion condensation theory. Polyols (sorbitol and mannitol) did not display the same effect. These compounds largely increase the relaxation rate of sodium ions in the proximity of DNA, unlike the zwitterionic compounds. This probably results from a perturbation of the water dynamic around the macromolecule, of the primary or secondary hydration shell of the sodium nuclei involved, or both.     

柱萤叶甲属研究（Ⅰ）鞘翅具黑色刻点的种类记述（鞘翅目：叶甲科）

本文就萤叶甲亚科中柱萤叶甲属鞘翅具黑色刻点的种类进行研究,共记述４种,我国已记录３种,其中１种为新种。