Sequential mechanism of refolding of carbonic anhydrase B

The kinetics of refolding of bovine carbonic anhydrase B was studied by a variety of methods over a wide range of times (from milliseconds to hours). It has been shown that protein refolding proceeds through three stages. At the first stage (t1/2 approximately equal to 0.03 s) hydrophobic clusters and a compact state of the chain are formed. At the second stage (t1/2 approximately equal to 140 s) hydrophobic clusters are desolvated and the rigid native-like hydrophobic core is formed. At the third stage (t1/2 approximately equal to 600 s) the native active protein is formed.     

Chromosomal evolution of the Common Shrew Sorex araneus L.from the Southern Ural and Siberia in the postglacial period]

This paper summarizes a series of studies on chromosomal geography of the common shrew Sorex araneus L. in Siberia and the Southern Urals. Chromosomal races inhabiting the Southern Urals and the Western Siberian Plain sequentially replace each other in the latitudinal direction. In this region, karyotypes of each two adjacent races differ from each other by a single whole-arm reciprocal translocation. In the Eastern Siberian branch, the neighboring races differ mainly in the number or set of metacentric chromosomes. Analysis of the race distribution in the common shrew in the context of paleophysiology of the glacial period allowed us to reconstruct the sequence of events leading to the establishment of the present-day structure of the species.     

AlkB homologues in thermophilic bacteria of the genus Geobacillus

Screening of alkane hydroxylase genes (alkB) was performed in the thermophilic aerobic bacteria of the genus Geobacillus. Total DNA was extracted from the biomass of 11 strains grown on the mixture of saturated C10-C20 hydrocarbons, PCR amplification of fragments of alkB genes was performed with degenerate oligonucleotide primers, PCR products were cloned and sequenced. For the first time in the genome of thermophilic bacteria the presence of a set of alkB gene homologues was revealed. The strains each contain three to six homologues among which only two are universal for all of the strains. Comparative phylogenetic analysis of the nucleotide sequences and the inferred amino acid sequences showed close relatedness of six of the revealed variants of geobacilli sequences to the alkB4, alkB3, and alkB2 genes that had previously been revealed by other authors in Rhodococcus erythropolis strains NRRL B-16531 and Q15. The rest two variants of alkB sequences were unique. Analysis of the GC composition of all the Geobacillus alkB homologues revealed closer proximity to the rhodococcal chromosomal DNA than to the chromosomal DNA of geobacilli. This may be an indication of the introduction of the alkB genes into the Geobacillus genome by interspecies horizontal transfer; and rhodococci or other representatives of the Actinobacteria phylum were probably the donors of these genes. Analysis of the codon usage in fragments of alkB genes confirms the suggestion that the pool of these genes is common to the majority of Gram-positive and certain Gram-negative bacteria. Formation of a set of several alkB homologues in a genome of a particular microorganism may result from free gene exchange within this pool.     

Effect of unithiol and acetylcysteine on lipid peroxidation and the erythrocyte antioxidant system in sensitized guinea pigs

The effect of unithiol and acetylcysteine on lipid peroxidation, thioldisulfide equilibrium, glucose-6-phosphate dehydrogenase, glutathione reductase and lactate dehydrogenase activity and on erythrocyte resistance was studied in guinea-pigs during sensitization with C. maltosa. Sensibilized animals receiving thiol antioxidants showed partial restoration of normal biochemical levels.     

The biological effects in animals in relation to the accident at the Chernobyl Atomic Electric Power Station. 5. Longevity and the carcinogenic effects]

Remote effects in laboratory animals living in conditions of exposure to a mixture of external and internal radiation resulted from the Chernobyl A.P.S. disaster have been investigated. It has been found that the rate of deaths from non-tumor illnesses grows, the incidence of neoplasms increases and their latency time decreases. The redistribution within the spectrum of benign and malignant tumors and the increase in the multiplicity coefficient have been revealed. It is concluded that chronic exposure of animals to low-level radiation from the radionuclides, resulted from the accident, brings about a much larger number of negative stochastic and nonstochastic remote effects as compared to those expected from the extrapolation of the effects produced by high radiation doses.     

Transglycosylation reactions catalyzed by Aspergillus niger 15 beta-xylosidase

The products of transglycosylation formed as a result of action of beta-xylosidase from Aspergillus niger 15 on p-nitrophenyl-beta-D-glucopyranoside and p-nitrophenyl-beta-D-xylopyranoside were studied by means of chromatography on sephadexes. They are formed at the substrate concentration of 10--100 mM with the amount 7--10 times less than that of hydrolysis products. Peculiarities of chromatography of substrates, products of transglycosylation and p-nitrophenol on Sephadexes G-15 and G-25 were analysed.     

Experimental study and numerical simulation of ion cyclotron heating of a hydrogen plasma in the T-11M tokamak

Results are presented from investigations of the possibility of heating a hydrogen plasma at the fundamental harmonic of the ion cyclotron frequency in the T-11M tokamak. The fluxes of charge-exchange atoms that escape from the plasma in the radial direction and across the toroidal magnetic field (transverse neutrals) were recorded by a Lakmus neutral particle analyzer. Measurements by the analyzer show that, during an RF pulse, the ion temperature increases by approximately 50–100 eV. Such plasma parameters as the ion temperature, rotation velocity, and isotopic composition were measured by a high-resolution spectrometer. According to the data from high-resolution spectroscopy, the ion temperature increases by approximately 150 eV. Results from numerical simulations of the ion cyclotron resonance heating of a hydrogen plasma in the T-11M tokamak are also given.     

Immunization with cellulose-immobilized antigens. The development of A. E. Gurvitch concept

A highly purified TUL4-CBD chimeric protein was obtained by one stage purification method. TUL4-CBD protein consists of TUL4 Francisella tularensis mature peptide sequence, Gly-Ser spacer and cellulose binding domain (CBD) of Anaerocellum thermophilum. The TUL4-CBD protein was shown to induce production of specific antibodies to TUL4 protein in laboratory animals.