Some unsolved aspects of the parasitism problem

Various interpretations of the parasitism phenomenon exist. In this work data supporting the ecological understanding of its nature are presented. For parasitic species formed in the process of evolution the host organism has become the habitat (nutrition, multiplication), i.e., the environment, where interactions between the host and parasites are governed by ecological regularities. The consequences of this interactions are different (disease, asymptomatic infection), being secondary they reflect the result of concrete interactions. For this reason parasitism should not be identified in terms of only one consequence of such interaction--the development of pathologic processes.     

Comparison of the Homologous SfeI and LlaBI Restriction–Modification Systems

A fragment containing the SfeI restriction–modification system (RMS) operon was cloned from a Streptococcus faecalis SE72 plasmid. Nucleotide sequence analysis revealed its high (99.2%) homology to the operon for Lactococcus lactis subsp. cremoris W56 LlaBI RMS recognizing the same site, 5"-CTRYAG-3". A substantial difference was that SfeI RMS operon had an additional 198-bp segment in the methylase gene and a larger gene for the putative control protein. No homology was observed between operon-flanking sequences of the two closely related species, suggesting horizontal transfer of the operon.     

Effect of shale kerogen oxidation products on biodegradation of petroleum and petroleum products in soil and water

Effect of oxidation products of shale kerogen (high-molecular-weight acids with 6-22 carbon atoms) on biodegradation of oil and oil products in soil and water was studied. High-molecular-weight acids (HMWA) not only affected the layer of oil and/or oil products and dispersed it into small particles, but also stimulated growth of Rhodococcus erythropolis VKM AS-1339D, degraders of oil and oil products. Addition of 0.001-0.003% HMWA to a medium to be purified from oil products increased the extent of bacterial biodegradation by a factor of 1.1-5.0.     

Interphase death of irradiated thymocytes--result of the "bystander effect"

It was shown that interphase death of thymocytes, which mechanism was established by author's laboratory already over 10 years ago belongs to phenomena which recently was named as caused by "bystander effect".     

The unique FauI restriction-modification system: cloning and comparative analysis of protein structure

The nucleotide sequence was established for the full-length Flavobacterium aquatile operon coding for the FauI restriction-modification system. The operon is unusual in structure and has the gene order control protein gene-DNA methyltransferase A gene-restriction endonuclease gene-DNA methyltransferase B gene, other than in the known analogs. The genes are similarly oriented and overlap. On evidence of sequence analysis, both methyltransferases are C5 enzymes, the control protein is similar to that of other restriction-modification systems, and restriction endonuclease is low-homologous to other enzymes cleaving the DNA upper strand in position 4 or 5 relative to the recognition site.