[Determination of critical kanamycin concentration for Mycobacterium tuberculosis in the MGIT Bactec 960 system].

The critical concentration of canamycin for the MGIT Bactec 960 system, which has been determined on a panel of the tho--roughly characterized genetically heterogeneous clinical Mycobacterium tuberculosis isolated in the Central Region of Russia, is equal to 1.25 microg/ml.

[Characteristics of the immune status in specific and nonspecific prophylaxis of influenza in elderly persons].

The results of the comparative analysis of the immunological effectiveness of the anti-influenza vaccine Vaxigrip, the inferferon inductor Arbidol and their combination in 125 elderly persons are presented. In the process of investigations the immunomodulating activity of the preparations under study was noted; this activity was manifested by the increase of the absolute and relative number of cells, carrying markers CD3+, CD4+ and CD16+, but not CD8+, CD19+ and CD25+, the normalization of the immunoregulatory index and the stimulation of the phagocytic function in the absence of essential influence on the level of HLA-DR+ expression and the concentration of immunoglobulins of the main classes. An increase in the frequency of seroconversions and the multiplicity of growth in the titers of specific antibodies to influenza viruses A (H1N1 and H3N2) and B, most pronounced in persons immunized with the vaccine simulianeouslywith the injection of Arbidol, was established.

[Specific features of minute structure of Mycobacteria cultured in murine macrophages]. / Osobennosti tonkoi struktury mikobakterii tuberkuleza, kul'tivirovannykh v makrofagakh myshi.

In experimentally infected murine peritoneal macrophages and murine macrophage-like cells J-774 with different pathogen strains of tuberculos'is, Mycobacterium tuberculosis (MBT) underwent significant morphofunctional changes. In phagocytosis, several live and mycobacteria conventionally referred by the authors to as morphotype I cells come from the environment to the macrophage. Of them, single young and intact mycobacteria are able to multiply and form at 2-3 generations morphotype II microcolonies from 3-9 mycobacteria or more in the phasolysosomes within the first 24 hours after infection. Having taken the form of small-sized cocci and coccoovals having a closely packed cytoplasm, morphotype II cells can be long present intact in the phagocytes. By losing the cellular wall under the action of lytic phagolysosomal enzymes, single mycobacteria turned into L-form or morphotype III MBT. During damage and lysis in the macrophages, single mycobacteria can preserve a part of an intact cytoplasm and genome as ultraminor forms of mycobacteria or morpho-type IV MBT.

Investigation of biosynthesis of human lymphotoxin in cells of recombinant Escherichia coli strain.

The effect of cultivation conditions on the biosynthesis of human lymphotoxin in recombinant Escherichia coli SG20050/pLT21 strain was studied. Cells of the producing strain were grown in Luria broth containing chloramphenicol. The highest biomass yield of the recombinant strain and plasmid DNA stability were observed under these conditions. To enhance the level of lymphotoxin production an inoculate containing freshly obtained or frozen with glycerol transformants of the producing strain were used, and the cultivation process was performed at 32 degrees C. As a result, lymphotoxin was synthesized in a soluble form without the formation of inclusion bodies. A study of the protein synthesis dynamics during the cultivation of E. coli at 32 degrees C showed that the highest lymphotoxin activity was observed during the exponential growth phase, being maximal at the end of the exponential phase and at the beginning of the stationary phase. The set of indicated methods allowed us to maximize and stabilize the production of lymphotoxin in a biologically active form with a final yield of 18-20% from cell protein.

[Antiviral properties of recombinant human lymphotoxin]. / Protivovirusnye svoistva rekombinantnogo limfotoksina cheloveka.

Study of the antiviral properties of recombinant human lymphotoxin obtained from Escherichia coli SG20050/pLT21 strain by microbiological synthesis showed this lymphotoxin to inhibit vesicular stomatitis virus on M-19 cells and exert a synergistic effect with recombinant human gamma-interferon. The drug exhibited no anti-HIV1 activity in experiments with MT4 cells pretreated with the virus or the drug itself; on the contrary, HIV1 reproduction in these cells was enhanced at low concentrations of the recombinant lymphotoxin.

[Recombinant human lymphotoxin: synthesis in Escherichia coli cells, purification, and certain properties]. / Rekombinantnyi limfotoksin cheloveka: sintez v kletkakh Escherichia coli, ochistka i nekotorye svoistva.

The biosynthesis of recombinant human lymphotoxin produced by E. coli SG20050/pLT21 cells and deprived of 21 amino acid residues has been studied. It has been shown that the bulk of the recombinant protein in E. coli cells is in the soluble form and predominantly localized in the cytoplasm. The maximal synthesis of soluble recombinant lymphotoxin is achieved during 24-hour cultivation of producing strain cells at 32 degrees C. A procedure for isolation and purification of the recombinant protein from E. coli cells has been developed. The purification is accomplished by gel-filtration on Sephadex G-150, ion-exchange chromatography on DEAE-Sephadex and CM-Sephadex, resulting in 97-fold purification and a 62% yield. The specific activity of the protein is about 1-10(8) U per mg of protein. Some physico-chemical properties of the recombinant protein have been studied.

[Cell proliferation induction in a monolayer chick embryo culture by the Sendai virus]. / Induktsiia proliferatsii kletok odnosloinoi kul'tury kurinnogo émbriona virusom Sendai.

The response of cells on monolayer chick embryo cultures to infection with Sendai virus was studied. Total infection leads to the death of the cells within 3--5 days postinoculation which permits this system to be considered as lytic. Its significant difference from other systems with the lytic outcome of interaction of non-oncogenic viruses with animal cells consists in marked enhancement of production of proper cellular RNA and proteins in the infected cells and an increase in their division rate preceeding their death.

[Reaction between the protein of gene 32 of phage T4 with DNA. Comparison of the properties of native protein and the product of its limited hydrolysis]. / Vzaimodeistvie belka gena 32 faga T4 s DNK. Sravnenie svoistv nativnogo belka i produkta ego ogranichennogo gidroliza.

Interaction between DNA and limited hydrolysate of T4 gene 32 protein has been studied. This limited hydrolysate is obtained when 8000 dalton segment of native 32 protein is removed proteolitically, its molecular weight being 26,000 dalton. It is shown that the melting temperatures of DNA as well as that of the synthetic homopolymer poly[d(AT)] complexed with this modified protein are more than 60 degrees lower than that of pure DNA and poly[d(AT]. The secondary structure defects in DNA promote its unwinding by the modified 32 protein. As follows from the analysis of the melting curves of the modified 32 protein -- DNA complex, this protein cooperatively binds to denatured DNA. The binding constants and cooperativity parameters are found to be equal to 10(8)--10(10) M-1 AND 10(3) respectively. It is shown that the gene 32 protein in the same environmental conditions does not destabilized native DNA and poly[d(AT)].

[Protein metabolism in chick embryo cells infected with Sendai virus]. / Ob osobennostiakh metabolizma belkov v kletkakh kurinogo émbriona zarazhennykh virusom Sendai

Inocluation of chick fibroblasts with Sendai virus results in a significant increase of protein synthesis. In cytoplasmic extracts of infected cells the content of polyribosomes increased and that of free (nontranslating) 80S ribosomes decreased, the "additional" polysomes of the infected cells being involved in protein synthesis. The portion of virus-specific protein synthesis in the infected cells was about 40% of the total protein synthesis. This means that with the total increase of protein synthesis 2-fold and (in some experiments) higher, the summary synthesis of cell proteins proper is not inhibited (possibly, it is slightly increased). Quite effective synthesis of virus-specific proteins for a comparatively long period after infection and ineffective maturation of virions eventually lead to a rather considerable accumulation of virus-specific proteins in the infected cells. The total content of protein in samples prepared 2 days after infection is approximately 1-1/2 as high as in uninfected samples.

[Synthesis of virus-specific macromolecules and virion maturation in chick embryo cells infected with Sendai virus]. / Sintez virusspetsificheskikh makromolekul i sozrevanie virionov v kletkakh kurinogo émbriona, zarazhennykh virusom Sendai

Synthesis and accumulation of virus-specific RNA, proteins and intracellular nucleocapsids are observed in Sendai virus-infected chick embryo cells for approximately 2 days postinfection. However, only an insignificant part of these products leaves the cell as a result of maturation of virus particles. It is suggested that the cause of the ineffective maturation of virions in the system under study may be in the observed instability of one of virus structural proteins in the infected cells, M protein. Some other suggestions on the mechanisms of nonpermissiveness of paramyxovirus systems expressed in literature earlier are also discussed.