[The determination of the antigenic determinant of protective monoclonal antibodies specific to the Francisella tularensis lipopolysaccharide]. / Opredelenie antigennoi determinanty preventivnykh monoklonal'nykh antitel, spetsifichnykh k lipopolisakharidu Francisella tularensis.

F. tularensis lipopolysaccharide (LPS) was studied with the use of monoclonal antibodies (McAb) having protective properties. The binding site of these McAb (IgG2a) is localized on the O-chain of LPS. In contrast to LPS isolated from vaccine strain 15, LPS isolated from F. tularensis cells in the R-form has no O-chains and does not interact with McAb.

[The LPS-protein complex from the outer membrane of Francisella tularensis]. / Issledovanie LPS-belkovogo kompleksa iz vneshnei membrany Francisella tularensis.

LPS-protein complex containing proteins of 15 kD, 17 kD and 19 kD was isolated from F. tularensis outer membrane by solving with sodium deoxycholate with the subsequent gel filtration on Sephacryl S-200. Protein of 17 kD constituted the main protein component of the complex. The LPS-protein ratio of this complex was 1:1. Proteins contained in LPS-protein complex have mainly the alpha-spiral structure. In the absence of detergent these proteins and LPS formed micelles with molecular weight exceeding 10(7) D. LPS-protein complex was shown to have a protective effect in mice infected with F. tularensis virulent strain 503.

[Study of the structural properties of recombinant leukocyte interferon A by means of fluorescence polarization, circular dichroism, and differential microcalorimetry]. / Issledovanie strukturnykh svoistv rekombinantnogo leikotsitarnogo interferon A metodami poliarizatsii fluorestsentsii, krugovogo dikhroizma i differentsial'noi mikrokalorimetryii.

Human leukocyte interferon-A1 (IFN-alpha A) structure in solution was investigated by fluorescence polarization, circular dichroism and scanning microcalorimetry techniques. Using gel-filtration it was established that at neutral pH values and at concentration not exceeding 0.3 mg/ml IFN-alpha A has a dimeric configuration in solution. At pH below 5, IFN-alpha A exists as a monomer. Using circular dichroism technique the IFN-alpha A molecule was shown to preserve a native structure upon decreasing pH to 3.5. The rotational correlation time of IFN-alpha A molecule in dimeric and monomeric form was measured using fluorescence of DNS, conjugated with the protein, and fluorescence of tryptophan residues. Our data indicate that the shape of IFN-alpha A molecule may be approximated by the rigid ellipsoid of revolution with the axis ratio = 4:1. The intramolecular melting of IFN-alpha A was studied by scanning microcalorimetry and circular dichroism in the acidic pH range. Thermodynamic analysis reveals two independent cooperative transitions. These transitions can be explained by assuming that the IFN-alpha A molecule consists of two structural domains.

[Biochemical, antigenic and protective properties of the outer membrane of tularemia pathogens]. / Izuchenie biokhimicheskikh, antigennykh i protektivnykh svoistv vneshnei membrany vozbuditelia tuliaremii.

The outer membranes of Francisella tularensis were studied. The membranes were identified morphologically, immunologically and biochemically. They contained 12-20% of protein, 15-30% of carbohydrates, up to 40% of lipids. The main integral proteins of the outer membranes were the 47, 43, 17 and 12 kD proteins. The main protein 63 kD was not integral. The lipopolysaccharides isolated from the outer membranes and acetone-dried cells did not possess the protective properties in experimental tularemia. The preparations of outer membranes possessed the protective properties for mice infected with the virulent strain 503. Chitosan amplified the protective properties of outer membranes.

[Changes in NMR-relaxation of plasma protons in animals during experimental carcinogenesis]. / Izmenenie IaMR-relaksatsii protonov plazmy krovi zhivotnykh pri ékperimental'nom kantserogeneze.

Studies were carried out of changes of NMR-relaxation of water protons bound to blood plasma proteins of linear animals in the course of induced cancerogenesis and total reaction of the organism to damage. It has been shown that the ratio between the times of spin-lattice and spin-spin relaxation can serve as a criterion of the development of induced cancerogenesis at histologically determined stage of its development.