The development of modified human Hsp70 (HSPA1A) and its production in the milk of transgenic mice

The production of major human heat shock protein Hsp70 (HSPA1A) in a eukaryotic expression system is needed for testing and possible medical applications. In this study, transgenic mice were produced containing wild-type human Hsp70 allele in the vector providing expression in the milk. The results indicated that human Hsp70 was readily expressed in the transgenic animals but did not apparently preserve its intact structure and, hence, it was not possible to purify the protein using conventional isolation techniques. It was suggested that the protein underwent glycosylation in the process of expression, and this quite common modification for proteins expressed in the milk complicated its isolation. To check this possibility, we mutated all presumptive sites of glycosylation and tested the properties of the resulting modified Hsp70 expressed in E. coli. The investigation demonstrated that the modified protein exhibited all beneficial properties of the wild-type Hsp70 and was even superior to the latter for a few parameters. Based on these results, a transgenic mouse strain was obtained which expressed the modified Hsp70 in milk and which was easy to isolate using ATP columns. Therefore, the developed construct can be explored in various bioreactors for reliable manufacture of high quality, uniform, and reproducible human Hsp70 for possible medical applications including neurodegenerative diseases and cancer.     

Nonstructural protein 1 of tick-borne encephalitis virus activates the expression of immunoproteasome subunits

The interaction of viral proteins with host cell components plays an important role in antiviral immune response. One of the key steps of antiviral defense is the formation of immunoproteasomes. The effect of nonstructural protein 1 (NS1) of tick-borne encephalitis virus on the immunoproteasome formation was studied. It was shown that cell expression of NS1 does not reduce the efficacy of the immunoproteasome generation in response to interferon-γ stimulation and even increases the content of the immunoproteasome subunits without the interferon-γ treatment. Thus, NS1 of tick-borne encephalitis virus activates, rather than blocks the mechanisms of immune defense in the cell.     

Possible mechanism of specific protein-nucleic acid interaction

It has been supposed that stereochemical fitness of amino acids into the cavities associated with their codons is used for specific recognition of nucleic acids by the proteins. In accordance with this hypothesis, amino acid side chains can insert into the cavity resulting from inverting the middle base of a nucleotide triplet in DNA. Certain experimental data seem to support the hypothesis. A model of specific binding between cro-protein from bacteriophage lambda with OR3 operator region of the bacteriophage has been proposed on the basis of the above hypothesis.     

The effect of functionally bound vitamins and their coenzyme forms on the activity of 2-oxoacid dehydrogenases in mouse organs

Ever-growing doses (beginning from the therapeutic up to 10-fold doses of a complex of five functionally bound vitamins (B1, FMN, nicotinamide, pantothenate, lipoic acid) being administered to F1 mice (CBA x Black) induced a constant and considerable rise of the pyruvate- and 2-oxoglutarate dehydrogenase (PDG and OGDG) activity in the mouse organs. In the in vitro experiments the addition of the corresponding coenzymes or their mixture (in the optimal concentrations) to the incubation medium containing mitochondria of the mouse liver led to a greater activation of these dehydrogenases in the group of animals which were preliminary injected the above complex of vitamins.     

Immunohistochemical study of the accumulation of antibody-forming cells in the lungs following intrapulmonary and subcutaneous administration of apneumotropic antigen]

Accumulation of the antibody-synthesizing cells in the lungs of guinea pigs in intratracheal and subcutaneous immunization was studied on a model of a complete typhoid bacilli antigen by means of Coons' method. Antibody-forming cells located in the interalveolar septi and in the peribronchial and perivascular connective tissue appeared with both method of the apneumotropic antigen administration. More of these cells accumulated in intrapulmonary application of the antigen. Repeated immunization by any method also led to the increase of their amount. The problem on the role played by the lungs in the immunogenesis is discussed.     

Taxonomic diversity of aerobic organotrophic bacteria from clean vietnamese soils and their capacity for oxidation of petroleum hydrocarbons

The dominant species and abundance of the cultured aerobic organotrophic bacteria were determined in the clean soils of the Republic of Vietnam. The total number of organotrophs varied from 2.0 × 10⁵ to 5.8 × 10⁸ CFU/g soil. A considerable fraction of the bacterial population (1.1 × 10⁵–9.5 × 10⁶ CFU/g soil) was able to utilize petroleum hydrocarbons as the sole carbon and energy source. Most of the organisms obtained in pure cultures were gram-positive bacteria; over 70% were hydrocarbon-oxidizing organisms. Analysis of 16S rRNA gene sequences resulted in tentative determination of the taxonomic position of 22 strains, with 12 belonging to the Firmicutes, 4, to the Proteobacteria, and 6 to the Actinobacteria. The most common bacteria capable of hydrocarbon oxidation belonged to the genera Acinetobacter, Bacillus, Brevibacillus, Chromobacterium, Cupriavidus, Gordonia, Microbacterium, Mycobacterium, and Rhodococcus. Some of the isolated Bacillus and Staphylococcus strains, as well as one Pseudomonas and one Sinomonas strain, did not utilize hydrocarbons. Gram-positive degraders, especially members of the order Actinomycetales, which exhibited high hydrocarbon-oxidizing activity, gained competitive advantage in the presence of hydrocarbons. This microbial group probably plays an important role in hydrocarbon degradation in tropical soils. Thus, Vietnamese soils, which had no history of petroleum contamination, support numerically significant and taxonomically diverse populations of h ydrocarbon-oxidizing bacteria.