Characteristics of hemagglutination reaction in methanotrophic bacteria

The reaction of hemagglutination with trypsin-treated rabbit erythrocytes was used to reveal lectins on the cell surface of methanotrophic bacteria and in their culture liquids. By this method, no lectins were detected on the cell surface of Methylococcus capsulatus IMV B-3001 and Methylomonas rubra IMV B-3075 or in the culture liquid of any of the species studied. With intact cells of Methylocystis parvus IMV B-3491, the positive hemagglutination reaction observed was nonspecific and most probably occurred due to the high cell surface hydrophobicity characteristic of this species.     

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 potentials for the laboratory diagnosis of infections caused by bacteria in the genus Campylobacter

Information on the laboratory diagnostics of Campylobacter infections, carried out with the use of traditional method and molecular biology methods which based on the study of the genetic apparatus of infective agents, is summarized. Classical bacteriological analysis ensuring the isolation and biochemical identification of bacteria, up to the determination of their species, complex bacteriological analysis permitting their isolation and phenotypic identification, as well as genotypic diagnostics in reference laboratories (the detection and identification of infective agents by means of molecular hybridization or gene amplification), may be used.     

The role of cytokines in the immunoreactivity modulation with bacteria of the Lactobacillus genus

Mechanisms of the immunomodulating and anticancerogenic action of bacteria of the genus Lactobacillus are updated on the basis of recent publications andown research. The impact of lactobacteria on the production of cytokines by the host as one of the most important factors mediating the modulating properties of these microorganisms is considered. Information on the capacity of lactobacteria to exhibit stimulating and suppressing effects on the immune system, to maintain the development and support oral tolerance and to ensure antitumor action is presented. The role of different cell components of lactic acid bacteria in inducing the cytokines synthesis is discussed. The mechanisms of the immunomodulating action of different probiotic preparations for the prophylaxis and correction of immunodeficient states associated with the development of dysbacteriosis and acute enteric infections are analyzed. The data on the oncostatic action of bacteria of the genus Lactobacillus are presented.     

Haptoglobin phenotypes differ in their ability to inhibit heme transfer from hemoglobin to LDL

LDL oxidation plays a pivotal role in atherosclerosis. Excellular hemoglobin (Hb) is a trigger of LDL oxidation. By virtue of its ability to bind hemoglobin, haptoglobin (Hp) serves as an antioxidant. Oxidation of LDL by hemoglobin was analyzed to occur by heme displacement from methemoglobin lodged in LDL. The LDL-associated heme is disintegrated, and iron inserted this way in LDL triggers formation of lipid peroxides. The genetic polymorphism of haptoglobin was found to be a risk factor in the pathogenesis of atherosclerosis. Individuals with Hp2-2 have more vascular incidences as compared to those with Hp1-1. In the current study, oxidation of LDL by metHb was carried out at physiological pH without addition of external peroxides. Hb-derived oxidation of lipids and protein was found to be practically inhibited by Hp1-1 but only partially by Hp2-2. Heme transfer from metHb to LDL was almost completely omitted by Hp1-1 and only partially by Hp2-2. We concluded that partial heme transfer from the Hb-Hp2-2 complex to LDL is the reason for oxidation of LDL lipids as well as protein. These findings provide a molecular basis for Hp2-2 atherogenic properties.     

Characteristics of plasmid pBS271 controlling epsilon-caprolactam degradation by bacteria in the genus Pseudomonas

Conjugative plasmids control the ability of five Pseudomonas strains isolated from the rectifiers of chemical plants to grow on epsilon-caprolactam as a sole carbon and nitrogen source. All the plasmids have a high molecular mass of their DNA (ca. 300 MDa) and control epsilon-caprolactam degradation at least to succinate. One of the plasmids (pBS271) belongs to the incompatibility group P-2 and suppresses the growth of a broad spectrum of temperate and virulent P. aeruginosa bacteriophages as well as that of some P. putida bacteriophages.     

On the hemagglutination reaction in methanotrophic bacteria

The reaction of hemagglutination with trypsin-treated rabbit erythrocytes was used to reveal lectins on the cell surface of methanotrophic bacteria and in their culture liquids. By this method, no lectins were detected on the cell surface ofMethylococcus capsulatus IMV B-3001 andMethylomonas rubra IMV B-3075 or in the culture liquid of any of the species studied. With intact cells ofMethylocystis parvus IMV B-3491, the positive hemagglutination reaction observed was nonspecific and most probably occurred due to the high cell surface hydrophobicity characteristic of this species.     

Glycine residues appear to be evolutionarily conserved for their ability to inhibit aggregation

Six glycine residues of human muscle acylphosphatase (AcP) are evolutionarily conserved across the three domains of life. We have generated six variants of AcP, each having a glycine substituted by an alanine (G15A, G19A, G37A, G45A, G53A, and G69A). Three additional variants had Gly45 replaced by serine, glutamate, and arginine, respectively. The mutational variants do not, on average, have a lower conformational stability than other variants with substitutions of nonconserved residues. In addition, only the G15A variant is enzymatically inactive. However, all variants, with the exception of the G15A mutant, form amyloid aggregates more rapidly than the wild-type. Dynamic light-scattering experiments carried out under conditions close to physiological confirm that aggregate formation is generally more pronounced for the glycine-substituted variants. Apart from the glycine at position 15, all other conserved glycine residues in this protein could have been maintained during evolution because of their ability to inhibit aggregation.     

Use of Lactobacillus to prevent infection by pathogenic bacteria

This review focuses on the use and potential of Lactobacillus to prevent infections of the urogenital and intestinal tracts. The presence and dominance of Lactobacillus in the vagina is associated with a reduced risk of bacterial vaginosis and urinary tract infections. The mechanisms appear to involve anti-adhesion factors, by-products such as hydrogen peroxide and bacteriocins lethal to pathogens, and perhaps immune modulation or signaling effects. The instillation of Lactobacillus GR-1 and B-54 or RC-14 strains into the vagina has been shown to reduce the risk of urinary tract infections, and improve the maintenance of a normal flora. Ingestion of these strains into the gut has also been shown to modify the vaginal flora to a more healthy state. In addition, these strains inhibit the growth of intestinal, as well as urogenital pathogens, colonize the gut and protect against infections as shown in mice. Other probiotic strains, such as Lactobacillus GG, have been shown to prevent and treat gastroenteritis caused by rotavirus and bacteria. Given that lactobacilli are not the dominant commensals in a gut which comprises around 10(10) organisms, much work is still needed to define the mechanisms whereby GR-1, RC-14, GG and other strains contribute to health restoration and maintenance. Such critically important studies will require the medical science community to show a willingness to turn away from pharmaceutical remedies as the only solution to health and disease.     

The protective properties of myelopeptides in the development of infectious processes caused by bacteria of the genus Salmonella

The protective properties of myelopeptides in the development of bacterial infection in mice and young pigs, caused by S. typhimurium 415, S. cholerae-suis 1422 and 370, have been studied. Myelopeptides have been found to possess protective properties when injected into animals infected with S. typhimurium and S. cholerae-suis in lethal doses. The best protective effect (survival rate of 100%) has been achieved by the injection of myelopeptides 24 hours before challenge. Myelopeptides have also been found to promote the weight gain of young pigs infected with S. cholerae-suis.     

Synthesis of C-linked triazole-containing AFGP analogues and their ability to inhibit ice recrystallization

C-Linked antifreeze glycoprotein (C-AFGP) analogues have been shown to have potent ice recrystallization inhibition (IRI) activity. However, the lengthy synthesis of these compounds is not amenable to large-scale preparation for the many commercial, industrial, and medical applications that exist. This paper describes the synthesis of triazole-containing AFGPs using a convergent solid-phase synthesis (SPS) approach in which multiple carbohydrate derivatives are coupled to a resin-bound synthetic peptide in a single step. Modified "Click" conditions using dry DMF as solvent with catalytic Cu(II), sodium ascorbate, and microwave radiation afforded the synthesis of AFGP analogues 9-12 in 16-54% isolated yield. Compound 9 demonstrated no IRI activity, while compounds 10, 11, and 12 were moderate inhibitors of ice recrystallization. These results suggest that, while the triazole group is a structural mimetic of an amide bond, the amide bond in C-AFGP analogue 3 is an essential structural feature necessary for potent IRI activity.     

Strain typing in the genus Lactobacillus

1. Introduction, 63
2. Techniques used for strain typing in the genus Lactobacillus , 63
3. Applications of strain typing in the genus Lactobacillus , 64,
4. Future prospects, 65
5. References, 65     

Bioconversion of phenyllactate to phenylalanine by bacteria of the genus Pseudomonas

The nature of phenylalanine auxotrophy in Pseudomonas sp. strain M9 was studied. A metabolic defect was found after the aromatic amino acid pathway branches from chorismate, so that the latter could not be converted to phenylpiruvate. It was shown that enzymatic activity of the strain could convert phenyllactate to phenylalanine. The reaction mechanisms were studied, and approaches to increasing the rate of the process and phenylalanine yield were proposed.     

Joint action of nitrofuran preparations and bile acids on bacteria of the genus Proteus]

Sensitivity of 25 fresh isolates of Proteus to some nitrofuran drugs most widely used in the clinical practice, such as furacillin, furagin, furazolidone and nitrofurantoin was studied. When the drugs were used in combination with some bile acids, i.e. desoxycholic, dehydrocholic, cholic and glycocholic acids, significant in vitro potentiation of the antibacterial activity of the nitrofurans against the isolates was observed. The combinations of the drugs with desoxycholic acid proved to be most effective. In the presence of this acid the bacteriostatic dose of the drugs decreased several thousand times. Combination of the nitrofurans with the other acids resulted in an increase in the antimicrobial activity amounting to several hundred times. The combinations of the drugs with the bile acids had not only bacteriostatic but also bactericidal effect.     

Characteristics of morphology and ultrastructure of bacteria of the genus Dethiosulfovibrio

Cell morphology and fine structure were studied in two strains of rod-shaped, strictly anaerobic, gram-negative sulfidogenic bacteria: strain SR12T (DSM 12538) and strain WS100 (DSM 12537) belonging to "Dethiosulfovibrio starorussensis." Cells of both strains, as well as cells of the type species of the genus Dethiosulfovibrio, D. peptidovorans, were found to possess multiple intracellular incomplete cross septa in the stationary growth phase.     

Structurally diverse disaccharide analogs of antifreeze glycoproteins and their ability to inhibit ice recrystallization

The β-d-galactosyl-(1,3)-α-N-acetyl-d-galactosamine disaccharide is present in antifreeze glycoproteins (AFGPs). Analogs of this disaccharide including the β-linked (1,3)-, (1,4)-, and (1,6)-galactosyl-N-acetyl galactosamine and the β-(1,3)-galactosyl-galactoside were synthesized and evaluated for ice recrystallization inhibition (IRI) activity. The results from this study demonstrate that the β-linked-(1,4) disaccharide exhibits more potent IRI activity than the native β-linked-(1,3) disaccharide. The C2 N-acetyl group of the disaccharide does not affect IRI activity but in monosaccharides, the presence of the C2 N-acetyl group decreases IRI activity. The current study will facilitate the design of potent small-molecule ice recrystallization inhibitors.