[Fungal diversity in the Antarctic active layer].

Taxonomic diversity of fungi in the samples of the active layer of Antarctica was investigated using conventional microbiological techniques and metagenomic analysis of total DNA extracted from environmental samples. The list of Antarctic microscopic fungi was expanded, including detection of the species representing a portion of the fungal complex, which is nonculturable or sterile on conventional nutrient media.

[Comparative morphological, ecological, and molecular studies of Aspergillus versicolor (Vuill.) Tiraboschi strains isolated from different ecotopes].

Cultural, morphological, ecological, and trophic properties (growth at different temperatures and on various organic substrates), as well as molecular and genetic peculiarities of Aspergillus versicolor (Vuill) Tiraboschi strains of different origins, were determined. The strains were isolated from different ecotopes (upper horizons of modern soils of several geographic regions, ancient soils and peat, and permafrost). No essential distinctions in cultural and morphological properties were revealed between the strains. Strains obtained from peat of the Aleutian Islands were characterized by the highest radial rates of colony growth. Some variations in the ITS loci of rDNA were observed in strains isolated from different ecotopes; the distinctions were most pronounced (1.7%) in the strain isolated from 100 000-year-old permafrost.

Cellobiose dehydrogenase formation by filamentous fungus Chaetomium sp. INBI 2-26(-).

Laccase-negative filamentous fungus INBI 2-26(-) isolated from non-sporulating laccase-forming fungal association INBI 2-26 by means of protoplast technique was identified as Chaetomium sp. based on partial sequence of its rRNA genes. In the presence of natural cellulose sources, the strain secreted neutral cellobiose dehydrogenase (CDH) activity both in pure culture and in co-culture with laccase-positive filamentous fungus INBI 2-26(+) isolated from the same association. INBI 2-26(-) also secreted CDH during submerged cultivation in minimal medium with glucose as the sole carbon source. Maximal CDH activity of 1IU/ml at pH 6 with 2,6-dichlorophenolindophenol (DCPIP) as an acceptor was obtained on 12th day of submerged cultivation with filter paper as major cellulose source. Cellulase system of Chaetomium sp. INBI 2-26(-) capable of adsorption onto H(3)PO(4)-swollen filter paper consisted of four major proteins (Mr 200, 95, 65 and 55K) based on SDS-polyacrylamide gel electrophoresis and was capable of DCPIP reduction without exogenous cellobiose.

[Expression of a cloned hemagglutinin-neuraminidase gene from Newcastle disease virus in murine myeloma cells]. / Ekspressiia klonirovannogo gena gemaggliutinin-neiraminidazy virusa bolezni N'iukasla v kletkakh myshinoi mielomy.

Vaccination with autologous cancer cells expressing a potent foreign antigen is promising for immunotherapy of tumors. A construct was obtained to transfect cancer cells with the hemagglutinin-neuraminidase (HN) gene of the Newcastle disease virus (NDV). Specific primers were designed, and the HN cDNA was amplified from RNA isolated from the allantoid fluid of NDV-infected embryonated chicken eggs. The amplified fragment was cloned in pCR2.1, sequenced, and recloned in expression vector pCDNA3.1/Zeo(+). The resulting construct was used to transfect mouse myeloma cells SP2/0. Production of HN was checked by ELISA and by a neuraminidase activity assay. Cell agglutination on ice was proposed as a test for surface HN.

[The interaction of monoclonal antibodies to the structural proteins of the Vnukovo-32 vaccinal virus with other viruses of the rabies group]. / Vzaimodeistvie monoklonal'nykh antitel k strukturnym belkam vaktsinnogo virusa Vnukovo-32 s drugimi virusami gruppy beshenstva.

The interaction of 7 monoclonal antibodies (MCA) to the nucleocapsid complex and 3 MCA to protein G of the vaccine virus Vnukovo-32 with 33 and 27 members of the rabies virus group, respectively, was studied. The indirect immunofluorescence test showed 7 MCA to the nucleocapsid complex to recognize 4 antigenic determinants (AD). Two MCA recognized the AD common for all the viruses under study. Individual ecological variants may be detected using other MCA. Three MCA to protein G had marked virus-neutralizing activity. MCA 1C5 neutralized all the rabies viruses under study. The other two MCA differed in the number of viruses they could neutralize. The viruses under study were divided into 4 groups depending on their interactions with certain MCA in neutralization test.

[The isolation and characteristics of hybridomas producing monoclonal antibodies to the structural proteins of the Vnukovo-32 strain of the rabies virus]. / Poluchenie i kharakteristika gibridom, produtsiruiushchikh monoklonal'nye antitela k strukturnym belkam virusa beshenstva, shtamm Vnukovo-32.

A series of hybridomas secreting monoclonal antibodies (MCA) to glycoprotein and nucleocapsid proteins of rabies virus strain Vnukovo-32 was selected as a result of fusion of splenocytes from immune BALB/c mice with cells of myeloma line Sp2/OAq14, screening and cloning by limiting dilution methods in semi-liquid agar. Four hybridomas secreted MCA to glycoprotein in high titres (5.0 x 10(5)-2.2 x 10(6)) and had marked virus-neutralizing and therapeutic properties. Eight hybridomas produced MCA to the nucleocapsid complex: five hybridomas secreted MCA of the G class in high titres (2.4 x 10(5)-1.6 x 10(6)) and three hybridomas secreted MCA of the M class in low titres.

[Expression of Staphylococcus aureus enterotoxin A gene in heterologous systems]. / Ekspressiia gena énterotoksiba A Staphylococcus aureus v geterologichnykh sistemakh.

The genomic library of Staphylococcus aureus genes on the plasmid vector pSL5 has been constructed. The library contains a 2.5 kb HindIII DNA fragment including the gene for enterotoxin A. The entA gene on the high copy number plasmids in the Escherichia coli cells deficient in proteolysis determines the synthesis of enterotoxin A in the amounts comparable to the ones in the parent strain Staphylococcus aureus FRI 722(H).

[The cloning and expression of the Staphylococcus aureus enterotoxin A gene in Escherichia coli cells]. / Klonirovanie i ékspressiia gena énterotoksina A Staphylococcus aureus v kletkakh Escherichia coli.

Gene ent-A has been cloned on phage vector pSL5 with the use of the gene library of S. aureus FR1722(H). It is located within DNA fragment Hind III having 2,500 nucleotide pairs.

Respecrins--a new type of compound with targeted action.

A new technique for the creation of compounds with targeted action is described. In such compounds, termed respecrins (receptor-specific, screened toxin), a physiologically active component carries an epitope-containing fragment of the target antigen and is screened or masked by antibody specific to this antigen. Interaction of the respecrin with the target cell results in dissociation of this immunocomplex, and thereby activation of the physiologically active component. The kinetics of dissociation of a respecrin during interaction with a cell were investigated by flow cytometry. Possible applications of the principle are illustrated by investigation on the antigen-dependent activation of the mitogenic activity of staphylococcal enterotoxin A.

[The effect of x-rays on the level, composition and para-nitroanisole-o-demethylase activity of cytochrome P-450 in the liver microsomes of rats]. / Vliianie rentgenovskogo oblucheniia na soderzhanie, sostav i para-nitroanizol-o-demetilaznuiu aktivnost' tsitokhroma P-450 v mikrosomakh pecheni krys.

A study was made of the effect of X-radiation of different doses on the content of P-450 cytochrome in a microsomal fraction of rat liver. When the haemoprotein level markedly decreased an increase in Km and a decrease in Vmax were noted in the reaction of O-demethylation of para-nitroanisole by microsomes of the irradiated rat liver. It is suggested that one of the cause of the effect observed is the postirradiation change in the composition of cytochrome P-450 pool resulting from a selective decrease in the level of the radiosensitive forms of haemoprotein.