A new method of producing NS5A antigen of hepatitis C virus.

A task of creating a universal platform for engineering affordable recombinant producers of viral proteins conserving immunogenicity has not been solved yet. High toxicity of the viral proteins for the host cells, low yield and abnormal folding of the products often present severe obstacles to obtaining producers of the viral proteins. In this work, we report a new method of engineering and screening of deletion libraries from the viral antigen genes.

[Study of the Accumulation of Rec A from Bacillus subtilis in the Mitochondria of a Recombinant Strain of the Yeast Yarrowia lipolytica].

No eukaryotic species has a system for homologous DNA recombination of the mitochondrial genome. We report on an integrative genetic systembased on the pQ-SRUS construct that allows the expression of the RecA recombinase from Bacillus subtilis and its transportation to mitochondria of Yarrowia lipolytica. The targeting of recombinant RecA to mitochondria is provided by leader sequences (5'-UTR and 3-UTR) derived from the SOD2 gene mRNA, which exhibit affinity to the outer mitochondrial membrane and provides cotranslational import of RecA to the inner space of mitochondria.

[Construction of the new Escherichia coli K-12 wild-type strain with improved growth characteristics for application in metabolic engineering].

MG1655 of Escherichia coli K-12 is frequently used in metabolic engineering as the wild-type strain. However, its two mutations, ilvG and rph-1 provide a negative effect on culture growth. The "polar effect" of rph-1 decreases the level of pyrE expression, causing partial auxotrophy for pyrimidines.

[New method of construction of artificial translational-coupled operons in bacterial chromosome].

The new method of translational-coupled operons construction in bacterial chromosome has been developed on the basis of recombineering approach. It includes construction in vitro of the artificial operon with efficiently translated proximal cistron followed by its insertion E. coli chromosome, modification of the operon due to Red-driven insertion of the special "Junction" with excisable selective marker in the intercistronic region of the initial operon and excising the marker.

[Tuning of expression level of the genes of interest located in the bacterial chromosome].

The new method of construction of the set of E. coli clones, differing in the promoter strength upstream the gene of interest, has been developed and tested using native E. coli MG 1655 lacZ gene as the reporter.

Escherichia coli ORF ybhE is pgl gene encoding 6-phosphogluconolactonase (EC 3.1.1.31) that has no homology with known 6PGLs from other organisms.

The pentose-phosphate pathway (PPP) is an important part of central metabolism in many organisms. A pgl(-) mutation that decreases the efficiency of the second stage of PPP has been described and mapped at approx. 17.

[Light effect at various wavelengths on gametogenesis of the Black Sea sea urchin (Strongylocentrotus nudus)].

Comparative study of the effect of light at wavelengths of 720 and 520 nm on the reproductive process in black sea urchin Strongylocentrotus nudus was performed in artificial conditions. The results obtained not only suggest the distinct influence of light on the reproductive process in sea urchin, but also indicate that its effects on oogenesis and spermatogenesis are different. Light at the wavelength of 720 nm was found to activate gonad development, while at the wavelength of 520 nm it had a suppressive effect by decreasing the oogonial and spermatogonial content without disturbing their cellular structure.

[The role of P-element sequences in the transcription activation].

A study was made of mutations resulting from insertion of the P element in the regulatory region of the yellow gene. Excision of the P element enhanced expression of yellow. Molecular analysis implicated P-element terminal sequences, which remained in the locus after the element was excised, in transcription activation of the yellow gene.

[Mechanisms of excising the P-element in a model system at the yellow locus of Drosophila melanogaster].

Patterns of excision of a single P element were studied in a model system of the yellow locus. The data obtained were in good agreement with the generally accepted SDSA (synthesis-dependent strand annealing) model. Specific features of P element excision in the presence of two tandemly repeated copies are presented.

[Determinants of resistance to chlortetracycline and other antibiotics in chlortetracycline-producing strain of Streptomyces aureofaciens].

Data are presented on resistance of Streptomyces aureofaciens strain TB-633 FU--the producer of chlortetracycline (CTC) to autogenous antibiotics and a number of other antibiotics. It is demonstrated that resistance to CTC is specified by ctr genes of constitutive expression as well as by inducible genes. CTC and ethidium bromide may serve as efficient inductors of inducible ctr genes.

[DNA cloning in actinomycetes: the creation of vector systems].

A new vector type was constructed on the basis of SLP 1.2 plasmid and the Kanr determinant of S. rimosus P3.

[Genetic instability of the production of antibiotic substances controlled by the SCP2 plasmid of Streptomyces coelicolor A3(2)].

Streptomyces coelicolor A3(2) strain bearing a variant of SCP2 plasmid produces three antibiotic substances: amromycin and streptocins A and B. After growth at elevated temperature (37 degrees C) of S. coelicolor A3(2), mutants which are not capable of producing amromycin and streptocins A and B (ant- mutants) were formed at high frequency (50%).

[Genetic control of pathways of pyrimidine metabolism in Aspergillus nidulans. 1. Isolation and genetic analysis of 6-azauracil resistant mutants].

147 mutants exhibiting the resistance to toxic effect of 6 azauracil have been isolated by nitrosoguanidine treatment from the wild strain of Aspergillus nidulans. This mutants have been divided into 11 phenotypic groups according to its cross-resistance to 5-fluoroderivatives of uracil, uridine and deoxyuridine. The genetic analysis has shown that all mutations of resistance are of nuclear origin and dominant nature, and they are distributed on six loci of the chromosome VIII.

[Metabolic pathways of exogenous pyrimidines in Aspergillus nidulans].

Studies on the susceptibility of the wild-type strain of Aspergillus nidulans to 6-azauracil suggest that it synthesizes pyrimidines using a by-pass pathway which is induced with 6-azauracil. The effect of a series of pyrimidines on the toxic action of 5-fluorouracil, 5-fluorouidine and 5-fluorodeoxyuridine has been investigated. As the result of these studies, a scheme is proposed for the metabolism of some pyrimidine bases and nucleosides in Aso.