Integrated mobile genetic elements in Thaumarchaeota

To explore the diversity of mobile genetic elements (MGE) associated with archaea of the phylum Thaumarchaeota, we exploited the property of most MGE to integrate into the genomes of their hosts. Integrated MGE (iMGE) were identified in 20 thaumarchaeal genomes amounting to 2 Mbp of mobile thaumarchaeal DNA. These iMGE group into five major classes: (i) proviruses, (ii) casposons, (iii) insertion sequence-like transposons, (iv) integrative-conjugative elements and (v) cryptic integrated elements. The majority of the iMGE belong to the latter category and might represent novel families of viruses or plasmids. The identified proviruses are related to tailed viruses of the order Caudovirales and to tailless icosahedral viruses with the double jelly-roll capsid proteins. The thaumarchaeal iMGE are all connected within a gene sharing network, highlighting pervasive gene exchange between MGE occupying the same ecological niche. The thaumarchaeal mobilome carries multiple auxiliary metabolic genes, including multicopper oxidases and ammonia monooxygenase subunit C (AmoC), and stress response genes, such as those for universal stress response proteins (UspA). Thus, iMGE might make important contributions to the fitness and adaptation of their hosts. We identified several iMGE carrying type I-B CRISPR-Cas systems and spacers matching other thaumarchaeal iMGE, suggesting antagonistic interactions between coexisting MGE and symbiotic relationships with the ir archaeal hosts.     

Inventing the dynamo machine: the evolution of the F-type and V-type ATPases

The rotary proton- and sodium-translocating ATPases are reversible molecular machines present in all cellular life forms that couple ion movement across membranes with ATP hydrolysis or synthesis. Sequence and structural comparisons of F- and V-type ATPases have revealed homology between their catalytic and membrane subunits, but not between the subunits of the central stalk that connects the catalytic and membrane components. Based on this pattern of homology, we propose that these ATPases originated from membrane protein translocases, which, themselves, evolved from RNA translocases. We suggest that in these ancestral translocases, the position of the central stalk was occupied by the translocated polymer.     

The Generation of Superoxide Radicals by Cardiac Mitochondria and the Antioxidant Effect of the Water-Soluble Form of Ubiquinol-10

Biophysics - We have studied the effect of the water-soluble form of ubiquinol-10 (CoQ10-H2) on the processes of electron transport, oxidative phosphorylation, and the formation of reactive oxygen...     

Effect of prenatal stress on the hypothalamo-hypophyseal-adrenal system activity and fat metabolism in the male water vole Arvicola terrestris

The HPA axis function and the fat metabolism were studied in adult male water voles born to intact mothers and mothers deprived of food on the 15th and 18th days of their pregnancy. The HPA response to emotional stress was relatively low in experimental males in winter. The hormonal response to a 24-hrs food deprivation diminished in experimental group only in February. The blood level of free fatty acids was increased in experimental group as compared to the control one. The short maternal food deprivation modified adaptive abilities of their male progeny.     

Chromosomal aberrations and parameters of oxidative stress in Chernobyl clean-up workers in a remote period after ionizing radiation

This investigation was performed to test a supposition about the influence of disturbances in antioxidative system on cytogenetical parameters in Chernobyl' clean-up workers. It was shown that some cytogenetical parameters straightly correlated with the parameters of oxidative stress, while other cytogenetical parameters show just reverse correlations. Apparently, these relationships are not of cause-and-effect type, but they reflect a complex processes occurring in humans for a long period after radiation exposure.     

Analysis of the N-Acetyltransferase 2 Gene Polymorphism in the Patients with Chronic Obstructive Pulmonary Disease and in Populations of the Volga–Ural Region

Restriction fragment-length polymorphism of the gene coding for N-acetyltransferase 2 (NAT2) was typed in populations of the Volga–Ural region (Bashkirs, Tatars, Chuvashes, Udmurts, and Russians) as well as in patients with chronic obstructive pulmonary disease (COPD) and in healthy individuals. Rapid and slow acetylator phenotypes were determined based on the presence or absence of the KpnI, TaqI, and BamHI restriction endonuclease recognition sites. The proportion of slow acetylators in the populations examined varied from 40.00% in Bashkirs to 64.15% in Chuvashes with statistically significant difference between these two ethnic groups (² = 5.7; P = 0.02). Overall, in the Volga–Ural populations slow acetylators represented 56.25% of the subjects examined. This value was similar to those presented in other studies of Caucasoid populations. In the COPD patients a statistically significant decrease of the slow acetylator frequency to 48.28% compared to healthy individuals (62.18%) was observed (² = 4.60; P = 0.036). The data obtained suggest a possible association between the drug resistance in the COPD patients with the rapid acetylator phenotype, which can lead to the development of the chronic form of the disease.     

Tomato root exudates and their effect on the growth and antifungal activity of Pseudomonas strains

The study of the effect of the root exometabolites of tomato plants on the growth and antifungal activity of the plant growth-promoting Pseudomonas strains showed that the antifungal activity of plant growth-promoting rhizobacteria in the plant rhizosphere may depend on the sugar and organic acid composition of root exudates.     

Polymorphism of genes for xenobiotic metabolism in petrochemical workers

Genetic polymorphism of xenobiotic metabolizing enzymes responsible for individual susceptibility to different environmental factors was examined in a cohort of petrochemical workers occupationally exposed to adverse action of chemical compounds. Molecular genetic analysis of the 1462V mutation in exon 17 of the CYP1A gene demonstrated close similarity between the genotype and allele frequency distribution patterns in the industrial and control groups. No association between the CYP1A polymorphic alleles and genotypes and the duration of service and concomitant diseases was observed. The odds ratio of the disease development in the workers carrying heterozygous CYP1A1 mutant allele was 2.2. Analysis of the STM1 gene polymorphism demonstrated a decrease in the frequency of the homozygous deletion carriers in the workers compared to the control group. There were no substantial differences between the industrial and control groups with respect to the frequencies of rapid and slow acetylator genotypes revealed at the analysis of the NAT2 gene polymorphism. However, considering the concomitant diseases, in the corresponding industrial subgroup a clear trend towards lower frequency of rapid acetylators was demonstrated. In addition, the odds ratio of the disease development for the workers with slow acetylator phenotype was 1.7.     

Two C or not two C: recurrent disruption of Zn-ribbons, gene duplication, lineage-specific gene loss, and horizontal gene transfer in evolution of bacterial ribosomal proteins

Background

Ribosomal proteins are encoded in all genomes of cellular life forms and are, generally, well conserved during evolution. In prokaryotes, the genes for most ribosomal proteins are clustered in several highly conserved operons, which ensures efficient co-regulation of their expression. Duplications of ribosomal-protein genes are infrequent, and given their coordinated expression and functioning, it is generally assumed that ribosomal-protein genes are unlikely to undergo horizontal transfer. However, with the accumulation of numerous complete genome sequences of prokaryotes, several paralogous pairs of ribosomal protein genes have been identified. Here we analyze all such cases and attempt to reconstruct the evolutionary history of these ribosomal proteins.

Results

Complete bacterial genomes were searched for duplications of ribosomal proteins. Ribosomal proteins L36, L33, L31, S14 are each duplicated in several bacterial genomes and ribosomal proteins L11, L28, L7/L12, S1, S15, S18 are so far duplicated in only one genome each. Sequence analysis of the four ribosomal proteins, for which paralogs were detected in several genomes, two of the ribosomal proteins duplicated in one genome (L28 and S18), and the ribosomal protein L32 showed that each of them comes in two distinct versions. One form contains a predicted metal-binding Zn-ribbon that consists of four conserved cysteines (in some cases replaced by histidines), whereas, in the second form, these metal-chelating residues are completely or partially replaced. Typically, genomes containing paralogous genes for these ribosomal proteins encode both versions, designated C+ and C-, respectively. Analysis of phylogenetic trees for these seven ribosomal proteins, combined with comparison of genomic contexts for the respective genes, indicates that in most, if not all cases, their evolution involved a duplication of the ancestral C+ form early in bacterial evolution, with subsequent alternative loss of the C+ and C- forms in different lineages. Additionally, evidence was obtained for a role of horizontal gene transfer in the evolution of these ribosomal proteins, with multiple cases of gene displacement 'in situ', that is, without a change of the gene order in the recipient genome.

Conclusions

A more complex picture of evolution of bacterial ribosomal proteins than previously suspected is emerging from these results, with major contributions of lineage-specific gene loss and horizontal gene transfer. The recurrent theme of emergence and disruption of Zn-ribbons in bacterial ribosomal proteins awaits a functional interpretation.     

Characteristics of the rat behavior following single and multiple exposures of the hypoglycemic insulin doses]

Rats behaviour in the "open field" changed in 2 hrs after a single episode of hypoglycaemia was abolished with glucose whereas no changes occurred in their stereotyped behaviour and intraspecies interaction. In 24 hrs quantitative parameters of the "open field" behaviour normalised although the behaviour still had an altered structure. At the same time, amphetamine-induced stereotyped behaviour's indices became reduced. These and other findings suggest some deeper behavioural changes in rats during their recovery from repeated hypoglycaemic episodes and absence of synchronisation of the insulin effects.