[The 25th anniversary of the State Scientific Research Center for Applied Microbiology. Achievements and prospects]

State Research Center for Applied Microbiology was founded in 1974 for accelerated development of molecular biology and molecular genetics in the USSR and rapid practical application of achievements of these sciences to economy and medicine.

[Creation and use of a liquid substance based on association of petroleum-oxidizing bacteria]

An association of four bacterial strains with high oil-oxidizing and bioemulsifying activities, psychrophilicity, resistance to chemical pollutants, and lack of pathogenicity was selected from a collection of natural oil-oxidizing microorganisms. A new liquid preparation containing stabilizers and preservatives that maintain the cell viability and oil-oxidizing activity during long-term storage was developed. A field experiment in oil-polluted sod-podzol and clay sand soils demonstrated that this preparation accelerated the biodegradation of oil and its individual fractions, especially in the presence of mineral and organic fertilizers. Treatment of oil-polluted soil with this preparation and additives decreased the oil-induced suppression of certain groups of soil microflora.

[Monitoring of life-threatening infection pathogens in relation to the problem of prediction of critical situations]

The epidemic situation in the context of many infectious diseases caused by bacteria is presently assessed as being poor in Russia and other countries. The spectrum of the pathogens that can deteriorate epidemic well-being is highly wide. The epidemic situation in terms of many infectious diseases, including those caused by such causative agents as Bacillus anthracis, Vibrio cholerae, Yersinia pestis, Francisella tularensis and others may deteriorate due to the emergence of their modified forms owing to their specific variability. The above generates the necessity of improving controlling measures or developing the techniques for monitoring the pathogens of infectious diseases, including those in the framework of international cooperation.

[Tularemia vaccine strain is a potential vector]

The immunological and genetic properties of Francisella tularensis vaccine strain are discussion with regard to its use to produce recombinant vaccines. This bacterium-based vector is supposed to be an excellent object for investigating the role of protective antigens in the development of immunity against intracellular bacteria.

[Designing the latex test system for express identification of legionella in the external medium and clinical materials]

A highly sensitive latex test system for identification of Legionella in the external medium and clinical materials have been designed. Protein antigens and polysaccharide components of the outer membrane of the agent were analyzed. Proteins having a molecular mass of 45, 29, and 24 kDa, as well as a polysaccharide component of LPS were found to be common for all L. pneumophila species. Highly affinic immunoglobulins to the antigenic components obtained were covalently linked with latex particles. The test system developed does not give cross-reactions with other microorganisms. The sensitivity of the system is 10(4) COE/ml. Testing water and clinical material samples confirmed that the developed system is more sensitive than the bacteriological method and the direct fluorescence test. In addition, the system is simple to use, cost-effective, it requires little time (no more than 5 min).

[Morphology, ultrastructure and populational features of bacteria francisella]

The morphology, ultrastructure of cells and the structure of microbial populations of various bacteria of the Francisella genus were estimated by electron microscopy. The strain 503 has been found to produce a bacterial population that is most homogeneous in shape and size. It contains microbes of only round and avoid forms, 0.5-0.6 micron in size. In addition of oval and round microbes there are ellipsoid and rod-shaped ones in the strains 15/3M, A. Cole 120, 117, etc. The largest tularemia microbes are typical of the strain Schu. The bacteria of all strains are covered by a capsule-like coat with well-defined borders. A thick capsule (0.12-0.35 micron) is specific for virulent strains whereas a thin capsular coat (0.06-0.12 micron) is encountered in vaccinal and avirulent microbes. The cells of the strain 503 were also shown to have the thickest envelope. All tularemia microbes have an asymmetric structure in the outer and cytoplasmic membranes due to the location of the bulk of intramembrane particles on their inner hydrophobic surfaces. Some F. tularensis microbes are able to produce keel-like protrusions on the outer membrane. The microbial nucleotide occupies 55-65% of the cytoplasmic volume and forms about 20-30 DNA-membrane contacts. Under unfavourable conditions, the microbes are capable of producing cell envelop protrusions and involutional cells, 0.1-0.3 micron in size.

[Stable expression of heterologous proteins in salmonella: problems and approaches to their designing]

Live attenuated Salmonella vaccines may be used as carriers of heterologous antigens. The optimum expression system for each heterologous antigen requires to be established on an individual basis. This will ensure that the antigen in question is produced at appropriate levels and in the correctly folded conformation. Different techniques for producing stable recombinant Salmonella strains suitable for their use as bivalent vaccines.

[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.

[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.

[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.

[Experimentally induced cholera in guinea pigs. I. Elaboration of the method of infection]

The method of intrapulmonary infection of guinea pigs was suggested for the assessment of the virulent properties of cholera vibrios. Addition into the diluent of 10% peptone, 10% gelatine and 0.05% agar-agar led to the reduction of LD50 by over 1000 times. A specific infectious process coursing in an acute generalized form with bacteriemia and affection of the small intestine developed in the infected animals. The majority of the animals perished in 1 to 2 days.