It was stated that spaceflight factors (SFF) affect the chromosomal DNA interchange during Streptomyces crossing. Cross polarity and primary input of a parent chromosome fragment in recombinant generation imply a more lasting cells contact in microgravity and a broader horizontal transport of genetic material. SFF had no effect on recombination frequency and mutation in a model of parental auxotrophic markers reversion to prototrophism. It was demonstrated that SFF boosted the fC31 phage exit from S. lividans 66 (fC31) and did not influence phage induction in S. coelicolor A3(2) (fC31). SFF inhibited synthesis of antiobiotic actinorhodin in lisogenic S. coelicolor A3(2), and tylosin and desmicosin in S. fradiae. Survivability of electrogenic bacteria Shewanella oneidensis MR-1 in space flight was higher compared with the synchronous control experiment. The reduction activity of S. oneidensis MR-1 as an indicator of electron generation effectiveness was identical in flight and laboratory samples.

Выделена и охарактеризована металлокарбоксипептидаза, продуцируемая штаммом Streptomyces bikiniensis 27 (ВКПМ Ас-1783) (КПSb). Фермент способен c равной эффективностью отщеплять от синтетических пептидов как основные, так и гидрофобные С-концевые остатки, т.е. обладает специфичностью карбоксипептидаз А и В млекопитающих. Фермент также гидролизует пептиды, имеющие на С-конце глутаминовую кислоту. КПSb имеет максимальную активность при рН 7,0-7,6 и 55°. Установлена последовательность участка ДНК, соответствующего зрелому ферменту КПSb в геноме S. bikiniensis 27 (ВКПМ Ас-1783) (Accession No GU362077). Показано, что первичная структура зрелого фермента имеет умеренную степень идентичности с ортологами из Streptomyces griseus (79% идентичности) и Streptomyces avermitilis (85% идентичности).

Sporulation in different strains of Bacillus licheniformis, 10716 and 1001 in connection with changes in synthesis of bacitracin was studied. It was shown that the sporulation efficiency did not depend on the synthesis of the antibiotic: in some strains with low potency for the antibiotic production, the sporulation level was lowered, while in the others, it was not lowered. Moreover, normal sporulation was also observed, when the synthesis of bacitracin was inhibited. Therefore, it is suggested that there is no correlation between the sporulation and antibiotic production.

Complexes of synthetic double-stranded polynucleotides and DNA with model peptides--L-Lys-L-Tyr-L-Lys and L-Lys-Gly-L-Lys have been investigated, using UV-spectroscopy. Polynucleotide complexes containing L-Lys-Gly-L-Lys were studied in order to consider the influence of lysyl residues on the polynucleotide melting temperature. It was shown, that L-Lys-L-Tyr-L-Lys lowers the melting temperature of all the polynucleotides studied, except poly(rI) . poly(C). The dependence of melting temperature of polynucleotide (DNA) . L-Lys-L-Tyr-L-Lys complexes upon the polynucleotide double helix form and GC-content has been detected. These effects have reflected the intercalation of peptide tyrosyl residues into one of the chains of the double-stranded polynucleotide. Correlation o the melting temperature dependences of polynucleotide complexes with gene 5 protein and L-Lys-L-Tyr-L-Lys upon polynucleotide double helix form and GC-content was found.

: The complexes of gene 5 protein (phage f1) with single-stranded and double-stranded polynucleotides were investigated by circular dichroism (CD). In our experiments the concentration of the protein varied accordingly to polynucleotide. A decrease of the CD amplitude for polynucleotide-protein complexes was shown in all the regions of wavelength studied. The data indicate that the protein is bounded to the polynucleotide. This protein bounds differently to double-stranded polynucleotides containing ribo-ribo, ribo-deoxyribo and deoxyribo-deoxyribo chains. This difference is explained by differences in the form of the secondary structure of polynucleotides, containing ribo-ribo, ribo-deoxyribo and deoxyribo-deoxyribo chains.

The data on the dependence of the melting curve parameters of double-stranded RNA (replicative form of RNA of f2 bacteriophage) poly(A) times poly(U) and poly(G) times poly(C) on the concentration of (C2H5)4NBr were obtained. The RNA melting range width is shown to pass through the minimum value T =2.1+/-0.1degrees at the point of inversion of relative stability of GC and AU pairs that corresponds to 4.0+/-0.1 M concentration of (C2H5)4NBr. Using the melting temperatures of poly(A) times poly(U) and poly(G) times poly(C) the rependence of Tgc-Tau parameter on (C2H5)4NBr concentration was shown. It was concluded from these data that the effect of the double-stranded RNA stacking heterogeneity was negligible in the 0-3 M range of (C2H5)4NBr concentration. Melting curves of RNA were obtained at various values of Tgc-Tau parameter. It was shown that the profile of fine structure of melting curves depends on the value of Tgc-Tau parameter.

Using UV-spectroscopy and circular dichroism (CD) phi KZ bacteriophage and its DNA were investigated. From the value of optical densities in the 320--400 nm range the size of the phi KZ bacteriophage's head was determined; the diameter of phi KZ bacteriophage head was found to be equal to 1300 +/- 100 A. phi KZ bacteriophage DNA has block structure and the GC-pair content is equal to 43.8 +/- 0.3%. phi KZ bacteriophage CD spectrum has an unusual profile (in comparison with known bacteriophage CD spectra); this spectrum is similar to the CD spectra of DNA in polyethylene glycole solution. To our knowledge CD spectra of such type were not obtained for other bacteriophages.

The effect of gene 5 protein from bacteriophage f1 on melting of double-stranded polynucleotides and DNAs has been investigated using the UV-spectroscopy method. A dependence of the melting temperature of polynucleotide (DNA)-gene 5 protein complexes upon the polynucleotide (DNA) GC-pair content has been detected. Using experimental data and examining some model systems we came to the supposition that the lowering of melting temperature of polynucleotide (DNA) induced by this protein is probably stipulated by intercalation of the protein tyrosyl residues into one of the chains of polynucleotide (DNA) double helix.

The influence of phage f1 gene 5 protein on melting of the synthetic polynucleotides has been investigated, using UV-spectroscopy. In our experiments we have varied the proteins concentration. It has been shown, that the protein lowers the melting temperature of the studied polynucleotides (d/A--Tn dAndTn, rAndTn, rAn.r n, dAn.rn). The melting temperatures and the shapes of melting curves of various polynucleotides differ when the same protein concentrations are used. We have shown that the protein binds to the double-stranded polynucleotides, containing ribo-ribo-, deoxyribo-ribo-chains. The difference in melting temperatures and shapes of melting curves was explained using the data about the differences in the secondary structure of these polynucleotides. Only for d/A-Tn renaturation was observed after sample cooling. It may reflect the single-stranded hairpin structure of this polynucleotide.

The secondary structure of methyl ester of deoxyadenylyl-(5'--3')-deoxyadenylyl-(5' leads to N)-L-phenylalanine [l-pheOMe-d (pApA)] has been investigated by proton magnetic resonance. For this compound folded conformation stabilized by hydrophobic interaction in aqueous solution has been shown; and the anti-anti-conformation has been proved to exist. The investigation of chemical shifts of aromatic protons in L-PheOMe-d (pApA) has permitted us to build the conformation model of this compound.

Nucleotidyl-(5' leads to N)-amino acids containing different heterocycle bases: adenine, guanine, hypoxanthine, cytosine, uracyl, and aromatic amino acids: phenylalanine, tyrosine and tryptophan, have been investigated by proton magnetic resonance and circular dichroism. For all the compounds studied folded conformation have been shown stabilized by hydrophobic interaction in aqueous solution. The comparison of the results of the studied nucleotidyl-(5' leads to N)-amino acids unable us to build four secondary structure types in these very compounds. Phenylalanine and tyrosine derivatives of purine nucleotides can be regarded as the first type, tryptophan derivatives of purine nucleotides as the second type, phenylalanine and tyrosine derivatives of pyrimidine nucleotides as the third type and tryptophan derivatives of pyrimidine nucleotides as the fourth type. For each group of these compounds conformational models have been built. In all these compounds the anti-conformation has been proved to exist.