Bioremediation Potential of Biochar-Immobilized Cells of Azospirillum brasilense

Microbiology - A biopreparation consisting of the cells of Azospirillum brasilense strain SR80 immobilized on wood biochar was characterized. Sorption of oil by biochar and its colonization by...     

Genetic diversity of the genus Lactobacillus bacteria from the human gastrointestinal microbiome

The species and strain genetic diversity of bacterial cultures belonging to the genus Lactobacillus, which were isolated from the gastrointestinal microbiome of the human population living in the former Soviet Union in the years 1960-1980, was studied. The bacteria demonstrated probiotic characteristics. Phylogenetic analysis of sequences of the gene coding for 16S rRNA detected earlier by us, showed that the gene found in bacteria isolated from the intestinal content of healthy adults and represented by species L. plantarum, L. helveticus, L. casei/paracasei, L. rhamnosus, and L. fermentum has high homology (97-100%) with this gene in type representatives of the species. The genotypic and strain diversity of cultures was studied using RAPD-PCR and nonspecific primers. This method with the use of the ERIC-1 primer gave reliable and reproducible results as compared that using with M13 and MSP primers and allowed the identification of examined bacteria belonging to the genus Lactobacillus at the level of species and certification at the strain level.     

The SCAR DNA sequence family is enrichment in the evolution-conserved sequences

Synaptonemal complex (SC) is a specific structure for prophase I of meiosis. Recently we have described synaptonemal complex tightly associated regions of DNA (SCARs DNA) as a particular family of genomic DNA. Now we reveal the evolutionary conservation of SCAR DNA sequences of vertebrates. This data correlates with universal morphology of SCs and similar processes proceed in prophase I of meiosis at representatives of different taxa.     

Pim family of protein kinases: Structure,functions, and roles in hematopoietic malignancies

Phosphorylation is the universal regulatory mechanism of key physiological processes, such as development, cell differentiation, proliferation, survival, and malignant transformation. The review considers serine/threonine protein kinases of the Pim (proviral integration of Moloney virus) family, which were initially discovered in experimental lymphomas. Data on the gene structure, evolution, functions, and substrates of Pim protein kinases are provided. The role in the biology of hematopoietic malignancies is discussed for Pim-1 as the major isoform. Pim-1 is a proproliferative and prosurvival protein kinase. Pim-1 is constitutively active owing to autophosphorylation, and its downstream partners positively regulate the cell cycle. Pim-1 cooperates with the c-Myc oncoprotein in leukemogenesis and, like the Akt protein kinase, prevents cell death. Thus, Pim kinases are regarded as new therapeutic targets. An original test system for a phenotypic screening of Pim inhibitors is presented. In this test system, the growth of a genetically engineered Escherichia coli strain in the presence of kanamycin depends on the phosphorylation of aminoglycoside 3′-phosphotransferase VIII by Pim-1, and pharmacological inhibition of this phosphorylation increases bacterial cell lysis.     

Antibiotic resistance of potential probiotic bacteria of the genus <Emphasis Type="Italic">Lactobacillus</Emphasis> from human gastrointestinal microbiome

Thirteen Lactobacillus strains isolated from the gastrointestinal microbiome of people from the territory of the former Soviet Union have been studied for resistance to 15 antibiotics of different nature, namely, penicillins, aminoglycosides, macrolides, lincosamides, tetracyclines, chloramphenicol, and rifampicin. The strains included four strains of L. plantarum, four of L. helveticus, three of L. casei/paracasei, one of L. rhamnosus, and one of L. fermentum. All strains showed relative sensitivity to ampicillin, chloramphenicol, rifampicin, roxithromycin, erythromycin, and azithromycin, while none of them were sensitive to all tested antibiotics. L. plantarum strains had the broadest resistance spectra: one strain was resistant to tetracycline and three aminoglycosides and three strains were resistant to tetracycline and five aminoglycosides; one strain demonstrated high resistance to clindamycin and two strains to lincomycin. At the same time, two L. plantarum strains demonstrated resistance to benzylpenicillin coupled with sensitivity to ampicillin, another β-lactam antibiotic. Such resistance was clearly not related to the β-lactamase activity and could be explained by a specific mutation in one of the penicillin-binding proteins of the cell wall. Strains of L. helveticus, L. casei/paracasei, L. rhamnosus, and L. fermentum exhibited cross resistance to two to five different aminoglycosides. A PCR test of the resistance determinants for the widely clinically used antibiotics, tetracycline, chloramphenicol, and erythromycin revealed the presence of the tetM gene of conjugative transposon in L. casei/paracasei and two L. helveticus strains. Nucleotide sequence analysis of the amplified tetM fragments demonstrated their high homology with the tetM genes of Enterococcus faecalis and Streptococcus pneumoniae. The strains carrying tetM were tested for the genes of replication and conjugative transfer of plasmids in lactic acid bacteria. The results indicated that these strains contain genes identical or highly homologous to the rep and trsK genes of the plca36 plasmid and rep gene of the pLH1 and pLJ1 plasmids of lactic acid bacteria. The tetM gene is probably not expressed in strains sensitive to the corresponding antibiotic. However, the investigated lactobacilli cannot be directly used as probiotics, as they may serve as a source of genes for antibiotic resistance in the human microbiome.     

The Pim family of protein kinases: structure, functions and roles in hematopoietic malignancies

Phosphorylation is the universal regulatory mechanism in key physiological processes such as development, cell differentiation, proliferation, survival and malignant transformation. In this review we analyze serine/threonine protein kinases of the Pim (proviral integration of Moloney virus) family that have been initially discovered in experimental lymphomas. We provide data on gene structure, evolution, functions and substrates of Pim protein kinases. Focusing on Pim-1 as the major isoform, we analyze its role in the biology of hematopoietic malignancies. Pim-1 is a pro-proliferative and pro-survival protein kinase. It is constitutively active due to autophosphorylation, and its downstream partners positively regulate the cell cycle. Pim-1 cooperates with c-Myc oncoprotein in leukemogenesis; furthermore, Pim-1, like the Akt protein kinase, prevents cell death. Thus, Pim kinases are regarded as new therapeutic targets. Finally, we present an original test system f or screening of Pim inhibitors. In this test system the growth of a genetically engineered Escherichia coli strain in the presence of kanamycin is dependent on the phosphorylation of aminoglycoside-3' phosphotransferase VIII by Pim-1: pharmacological inhibition of this phosphorylation increases the bacterial cell lysis.