Solubilization of IgG-binding proteins from group A and G streptococci

The release of IgG-binding proteins from the cell surface of streptococcal strains AR-1 and G148 with various proteolytic enzymes, acid, alkali or SDS was investigated. The IgG-binding proteins were purified by affinity chromatography using IgG-Sepharose Fast Flow. After SDS-polyacrylamide gel electrophoresis and immuno-electroblotting the major proteins identified varied in relative molecular mass from 15,000 to 65,000 depending on the solubilizing agent used. The results showed that solubilization with trypsin gave the highest yield of IgG-binding proteins, that strain G148 yielded about twice the amount of protein as strain AR-1, and that elastase released an IgG-binding protein of high relative molecular mass of 65,000.     

Mercuric reductase enzymes from Streptomyces species and group B Streptococcus

Mercury volatilization (Hg2+ reductase) activity has been found with Hg2+-resistant isolates of three Streptomyces species and with three Hg2+-resistant strains of group B Streptococcus from clinical sources in Japan. Hg2+ reductase activities in crude cell extracts showed the temperature sensitivity, the requirement for an added thiol compound and the characteristic dependence on NAD(P)H cofactors of similar enzymes isolated from other bacteria.     

Isolation and characteristics of surface proteins from Streptococcus group A

Cell wall surface proteins of group A Streptococcus type 29 were extracted with 1 M hydroxylamine pH 6.0. The purification procedure included fractionation with ammonium sulfate and gel filtration on Sephadex G-150. SDS polyacrylamide gel electrophoresis revealed a number of proteins (approximately 20) with molecular mass of 70 kD; the difference in Mr between the proteins was 5-10 kD. Isoelectrofocusing demonstrated that the proteins are either acid (pI = 3.7) or weakly alkaline (pI = 7.7). Possible reasons for the heterogeneity of Streptococcus cell wall surface proteins are discussed.     

Are Trichogramma bourarachae and the perkinsi species group really distinct from Trichogramma buesi and the pintoi group,respectively?

Abstract:  The two Trichogramma species T. bourarachae and T. buesi belonging to two closely related groups, perkinsi and pintoi , were compared. The inter-species crossings did not result in hybrids and, therefore, the two species show complete genetic isolation. Eleven morphometric characteristics (eight from male genitalia and three from male antennae) and seven ratios between the latter characters confirmed the validity of these species. Significant differences (P < 0.01) actually exist for 56% of the measured characters and the calculated ratios. Among the morphometric characters analysed, five contribute to the definition of the perkinsi and pintoi groups and allow for comparisons to be made. However, only two of them (40%) show a difference between the groups (P< 0.01). Such a result, in accordance with those from other studies, has led to the combination of the two groups synonymously, under the name of perkinsi .     

Kunitz-type protease inhibitors group B from Solanum palustre

Five Kunitz protease inhibitor group B genes were isolated from the genome of the diploid non-tuber-forming potato species Solanum palustre. Three of five new genes share 99% identity to the published KPI-B genes from various cultivated potato accessions, while others exhibit 96% identity. Spls-KPI-B2 and Spls-KPI-B4 proteins contain unique substitutions of the most conserved residues usually involved to trypsin and chymotrypsin-specific binding sites of Kunitz-type protease inhibitor (KPI)-B, respectively. To test the inhibition of trypsin and chymotrypsin by Spls-KPI proteins, five of them were produced in E. coli purified using a Ni-sepharose resin and ion-exchange chromatography. All recombinant Spls-KPI-B inhibited trypsin; K(i) values ranged from 84.8 (Spls-KPI-B4), 345.5 (Spls-KPI-B1), and 1310.6 nM (Spls-KPI-B2) to 3883.5 (Spls-KPI-B5) and 8370 nM (Spls-KPI-B3). In addition, Spls-KPI-B1 and Spls-KPI-B4 inhibited chymotrypsin. These data suggest that regardless of substitutions of key active-center residues both Spls-KPI-B4 and Spls-KPI-B1 are functional trypsin-chymotrypsin inhibitors.     

棉铃虫Ⅰ型几丁质酶的表达

昆虫几丁质酶主要参与昆虫蜕皮、围食膜降解、细胞增殖、机体免疫防御、生长因子等重要生理生长发育过程。在本研究中,从NCBI下载棉铃虫几丁质酶序列,并克隆验证正确,构建的系统发育树表明属于Ⅰ型几丁质酶。将不包含信号肽的开放阅读框序列(1 707 bp)与pET28a载体连接,转化至大肠杆菌transetta(DE3)中进行诱导表达,Western blot进一步验证融合蛋白His-HaCHT。用镍柱子纯化融合蛋白,纯化获得的融合蛋白对胶体几丁质有降解活性,其酶活力为0.023μg/mL·s~(-1)。不同龄期的qPCR结果显示,该基因在棉铃幼虫的6个幼虫期以及预蛹蜕皮后均有表达,但HaCHTI在4龄和6龄幼虫阶段表达相对较高,而在1龄、2龄、3龄、5龄幼虫和预蛹表达量较低。这些结果表明,异源表达的棉铃虫的I型几丁质酶对胶体几丁质具有降解活性,可能对棉铃虫正常蜕皮有着重要的作用。     

The presence of blood group A-active glycolipids in cancer tissues from blood group O patients

Glycolipids were isolated from human gastric cancer tissues and normal mucosae. Sulfogalactosylceramide, ganglioside and neutral glycolipid fractions were separated by DEAE-Sephadex and silica gel column chromatography. Sulfogalactosylceramide contents were higher in the cancer tissues than in the normal mucosae. Ganglioside contents showed considerable variations but in the cancer tissues in mole percentage of ganglioside GM3 was higher than in the normal mucosae. The cancer tissues contained more neutral glycolipids than normal tissues. Glycolipids of lacto-series, including fucolipids, were markedly increased in the cancer tissues. Blood group A-active glycolipids were found in the cancer tissues from two patients with blood group O but not found in the uninvolved tissue associated with the cancer tissue.     

Unit cell and space group of catalase from Micrococcus luteus.

Octahedral shaped crystals of about 1 mm were grown from catalase of Micrococcus luteus. The space group was determined as P4₂2₁2₁ with $\text{a = b = 106.6}\text{A}\text{?}\text{and}\text{c = 106.3}\text{A}\text{?}$. In contrast to mammalian catalase, the bacterial catalase contains only one subunit per asymmetric unit. This proves that the four subunits of bacterial catalase are identical.     

Typing of Streptococcus group A isolated from patients and healthy persons

The typing of 80% of 381 streptococcal strains, group A, under study was accomplished with a set of diagnostic anti-T sera obtained from the Sevak Institute (Czechoslovakia). None of the T-types could be related with certainty to the localization of the infective agent in the human body (the pharynx, the skin). Different T-types were shown to circulate in definite regions of the USSR. To enhance the differentiating capacity of T-typing, the enzymatic (lipoproteinase and NADase) activity of the strains was determined, thus permitting the subdivision of the T-types into still smaller groups. The typing of OF+ strains of unknown M-specificity could be carried out by means of the blood sera of healthy persons, containing antibodies to streptococcal lipoproteinase. The conclusion on the expediency of using the determination of lipoproteinase and NADase as an additional marker in the typing of group A streptococci was made.     

Individual and group adaptation in space: evidence from analogue environments

As the duration of space missions increases and crews become more heterogeneous, psychological and interpersonal factors are likely to play an increasingly important role in determining mission success. Empirical evidence about psychological factors in space has to a large extent been based on personnel in analogue environments. Studies in these environments have included effects of multi-nationality on crew interaction, gender issues, development of tension within crews and in relation to Mission Control. Results so far demonstrate the need for countermeasures designed to address psychological and interpersonal dysfunctions, specifically selection, training and in-flight support.