Isolation of Rec mutants of Bacillus subtilis via insertional mutagenesis]

A number of mutants supersensitive to mytomycine C were isolated via insertion of Tn917 into Bacillus subtilis chromosome. Six Rec mutants with lower transformation frequency, though with nondisturbed capacity of DNA binding and uptake, were isolated. Two of these mutations are situated in those chromosomal sites where location of Rec genes had not yet been registered.     

Enzyme-linked immunosorbent assay for determination of cyclosporin a in the whole blood

A test-system based on enzyme-linked immunosorbent assay (ELISA) for quantitative determination of cyclosporin A (CSA) in human whole blood has been developed. The detection limit of the method was 25 ng/ml, the linearity of the method in the concentration range of 60–1400 ng/ml varied from 94 to 105%, the variation coefficient did not exceed 8%. The novel method exhibited good correlation with radioimmunoassay and polarization fluoroimmunoassay methods; the linear regression coefficients were 0.965 and 0.984, respectively. The developed test system is stable for at least 9 months when stored at 4°C and can be used in clinical practice.     

Occurrence of markers, distribution of genotypes and risk factors for viral hepatitis C among some groups of the population in the Novosibirsk region

The occurrence of markers, genotypic variability of isolates and risk factors for viral hepatitis C (HCV) were studied in 4 groups of residents of the Novosibirsk region (altogether 2,000 persons). Anti-HCV IgG were detected within the range from 4.6% among medical personnel to 48% among the patients of the drug-abuse clinic. The detection rate of HCV RNA in seropositive samples varied from 79.3% to 86.3%. The determination of genotype was carried out for 388 isolates: 1b--50.3%, 2a--4.4%, 2c--0.3%, 3a--44.8%. The highest risk indices with respect to HCV among the residents of the region were linked with the drug use (OR=77.5; p<0.05) as well as with risky behavior and low social status. The elevated numbers of seropositive persons were detected among unemployed (OR=16.3), alcohol abusers (OR=3.9), persons having more than 4 sex partners in their lifetime (OR=4.3) and persons having homosexual contacts (OR=6.6). In some groups blood transfusions also played a definite role in the transmission of HCV. In the analysis, carried out separately for two different genotypes the intravenous use of drugs was perceptibly stronger linked with VHC of genotype 3 (OR=85.5) in comparison with HCV of genotype 1 (OR=49.3) and genotype 2 (OR=41.1). Genotype 1 prevailed in the older age group and genotype 3, among young people.     

Some of eukaryotic elongation factor 2 is colocalized with actin microfilament bundles in mouse embryo fibroblasts

Indirect immunofluorescent microscopy was used to study the distribution of eukaryotic elongation factor 2 (EF-2) in cultured mouse embryo fibroblasts. The perinuclear area (endoplasm) of all the cells and many straight cables running along the whole cytoplasm were stained with monospecific goat or rabbit antibodies to rat liver EF-2. Double staining of the cells with antibodies to EF-2 and rhodaminyl-phalloidin (used for actin microfilament detection) showed that EF-2 containing cables coincided with bundles of actin microfilaments. Not all actin microfilament bundles contained EF-2: sometimes EF-2 was not observed in bundles running along the cell edges or in actin microfilament junctions. Triton X-100 extracted most of EF-2 from the cells and no actin microfilament bundles were stained with the EF-2 antibodies in the Triton-extracted cells. Thus, in mouse embryo fibroblasts EF-2 can be found along actin microfilament bundles, but it is unlikely to be their integral protein.     

Production of rabbit precipitating antisera to subclasses of human IgG]

Precipitating antisera to human subclasses IgG were obtained by immunization of rabbits by whole molecules IgG2, IgG3, IgG4 and gamma 1-chains derived from IgG1H (Pr). Analysis of the antisera obtained demonstrated that rabbits produced specific antibodies to the antigenic subclass determinants IgG3 well, to IgG2, IgG4--much worse, and failed to produce specific antibodies to subclass IgG1 (in immunization with whole molecules of this protein). Antisera contained antibodies to the antigenic determinants common of IgG, and antibodies to light chains which were removed by immunosorption, for which purpose a sorbent on the basis of BrCN sepharose conjugated with IgG of the three other subclasses and Fab-fragment was used.     

Determination of the subclasses of monoclonal human immunoglobulins G and of the light chain type with the aid of specific antisera]

Sera of 86 patients suffering from G-myeloma were studied for the purpose of determination of subclasses of monoclone IgG. Investigations were carried out by means of antisera to subclasses IgG by the double diffusion method in gel after Ouchterlony. The following distribution of myeloma Ig was revealed: G1--70%, G2--17%, G3--11%,and G4--2%. In typing of the light igG chains by the method of immunoelectrophoresis, using antisera to the light chains of immunoglobulins of the chi and lambda type it was found that IgG1 chi was encountered more frequently than IgG1 lambda (3:1 ratio). The amount of the sera with the IgG2, IgG3, and IgG4 was insufficient for the reliable conclusion of their distribution by the type of light chains.     

Use of immunoenzyme analysis for controlling the activity of antisera to insulin

Antisera to insulin were obtained from guinea pigs hyperimmunized with the use of Freund's adjuvant. To control the specific activity of antisera, the highly specific modern method of ELISA was used. Insulin was allowed to adsorb on the surface of the wells of polystyrene microplates, then consecutive dilutions of the tested antisera to insulin were placed into the wells. The insulin-antibody complexes thus obtained were detected by means of immunoperoxidase conjugate. Antibody titers in antisera obtained from different animals varied from 5 X 10(-3) to 10(-5). A good correlation between the results obtained by ELISA and by radioimmunoassay was observed.