The opsonizing activity of the sera of hamadryas baboons immunized with a preparation of the outer membranes of Francisella tularensis (based on data from the luminol-dependent luminescence method)]

The opsonizing properties of sera obtained from hamadryas baboons immunized with the preparation of F. tularensis outer membranes (OM) were studied with the use of luminol-dependent chemiluminescence (CL) of whole blood. The immunization of monkeys with the OM preparation was shown to lead to the formation of functionally active antibodies possessing opsonizing properties with respect to virulent F. tularensis. Immune sera obtained from the animals immunized with live vaccine and from those immunized with OM preparation had no essential differences in their opsonizing properties. The level of IgG antibodies in immune sera correlated with the CL parameters of whole blood in the presence of F. tularensis opsonized with these sera. Increased CL of phagocytes observed after addition of bacteria and immune sera under test to whole blood taken from a nonimmune donor made it possible to evaluate the functional activity of antibodies, thus permitting its use as a test for the evaluation of the effectiveness of new vaccine preparations.     

Radiation-induced, irreparable, hereditary changes in cells promoting their neoplastic transformation

In experiments with model plant tumors (Kalanchoe-ti plasmid Agrobact. tumefaciens C-58D) it was shown that exposure of the recipient plant to low-level gamma-radiation of 2 Gy induced changes in cells that were not repaired over two months promoting tumoral transformations in them. Those changes were shown to persist in the offspring of the exposed somatic cells.     

Quinoid radiotoxins in the blood of gamma-irradiated dogs

Quinoid radiotoxins were found in the peripheral blood 3-4 h following gamma-irradiation of dogs with doses of 5.76 Gy. The authors developed a simple method of isolation and purification of quinoid radiotoxins and specified their physicochemical and biological characteristics.     

The characteristics of the antibody response of animals immunized with components of the surface structures of Francisella tularensis

Antibody formation in animals immunized with one of the components of F. tularensis surface structures was studied. The time course of antibody formation in 20 hamadryas baboons was studied in the passive hemagglutination (PHA) test, microagglutination (MA) test, and indirect enzyme immunoassay, used for the determination of IgG, IgA and IgM antibodies. The character of antibody response in the animals immunized with components of F. tularensis surface structures (S-complex) and with live tularemia vaccine was compared. The study revealed that immunization with the S-complex induced the formation of antibodies detected by all three methods. Antibody formation to the S-complex was found to be dose-dependent. With the increase of the injected dose of the S-complex, antibody titers determined in the PHA test decreased and those determined in the MA test increased, which was seemingly due to the induction of antibodies differing in their isotypes. After immunization with the S-complex the levels of IgG antibodies were lower and the levels of IgM antibodies by day 28 after immunization higher than after the injection of live tularemia vaccine.     

Correlation of polymorphism of heterochromatin segments with hybridization on chromosome preparations of various cloned repeated human DNA sequences

Comparison between results of measurements of heterochromatic regions detected by differential C and DA/DAP1 staining and the hybridization data of two cloned repeated human DNA sequences one alphoid (pH S05) and the other the satellite DNA III (pPD18) on chromosome preparations was made. A positive correlation of heterochromatic region sizes on several chromosomes and the amount of label over them detected after hybridization with both alphoid and satellite sequences was shown, the correlation with the latter being more pronounced.     

The use of ultrafiltration for concentration and purification of beta-galactosidase

A possibility of concentration and purification of culture fluid of Escherichia coli by the ultrafiltration technique using Soviet cellulose acetate membranes were studied. It is established that cellulose acetate membranes may be used for purification from low molecular weight protein and concentration of preliminarily purified culture fluid of Escherichia coli. Membranes YAM-300 are most preferable. At the temperature of 18 degrees C, pressure 0.16-0.24 MPa and 20-fold concentration the yield of the enzyme at the ultrafiltration stage was 84.5%.     

Optimization of the conditions for the in situ hybridization of cloned DNA sequences and for the differential staining of human chromosomes

The influence of different experimental conditions on in situ hybridization of DNA and subsequent differential staining of chromosomes was studied. The most optimal conditions for chromosomal localization of cloned repetitive DNA sequences were the lack of chromosome pretreatment with acid and RNase, reduction of the denaturation time to 30 s, carrying out of hybridization at a relatively low temperature (under 37 degrees C) at the expense of the use of formamide, addition to the hybridization mixture of 10% of dextran sulfate-500. The conditions indicated permit obtaining on radioautographs the G- and C-segmentation of human chromosomes.     

Method of diagnosing aneuploidies using in situ hybridization: analysis of interphase nuclei]

The possibility of determining chromosomal sex using in situ hybridization of X-specific alphoid DNA probe with interphase human nuclei is studied. Total number of nuclei under study being 14806, more than 85 percent of female ones and more than 95 per cent of male ones are shown to contain two and one grain clusters, respectively. The minor nuclear classes, i.e. containing other numbers of grain clusters, may reflect the effects of polyploidization and cluster aggregation resulting from spatial chromosome distribution. Therefore the positive analysis of sex chromosome constitution on the base of the applied method is possible.     

The use of microdot immunoenzyme analysis with visual detection for the determination of tularemia antibodies

The possibility of using the micropoint enzyme immunoassay (EIA) on a nitrocellulose membrane with the visual evaluation of results for the detection of tularemia IgG antibodies in hamadryas baboons at the postvaccinal period has been studied. The sensitivity of this assay has been compared with that of the passive hemagglutination (PHA) test, the microagglutination (MA) test and EIA with the spectrophotometric evaluation of results in plates. As shown in this study, EIA in the above-mentioned modification can be successfully used for the detection of tularemia antibodies in the blood serum. The sensitivity of micropoint EIA has proved to be not inferior to that of EIA in plates, while exceeding the sensitivity of the PHA test 10- to 20-fold and the sensitivity of the MA test 10- to 1,000-fold. This method is simple, reliable, highly sensitive, economic and requires no special equipment, which makes it highly promising for the diagnosis of tularemia and the evaluation of humoral immunity at the postvaccinal period.