[Biological activity of native and modified lipopolysaccharides Rahnella aquatilis].

The results of the comparative toxicity studies of native lipopolysaccharide (LPS) of Rahnella aquatilis 96U037 and that modified by tin complexes indicates that, due to the modification of LPS by tin complex with benzoylhydrazone of 4-dimethylaminobenzaldehyde, a decrease of its toxicity was observed that led to disappearance of the pyrogenic effect. All obtained derivatives lost completely the antigenic activity both in homologous and heterologous systems which may indicate to the interaction of modifying complexes with certain groups being the components of antigenic determinant. The paper is presented in Ukrainian.

[Chemical characterisation of structural components of Rahnella aquatilis lipopolysaccharides].

The studies of lipopolysaccharides (LPS) of eight Rahnella aquatilis strains, isolated from different sources have shown that they contain both S- and R-types of molecules. This fact is evidenced by the presence of high-molecular fraction of O-specific polysaccharides (O-PS) and low-molecular fraction of core oligosaccharides. The predominant monosaccharides of core oligosaccharides were glucose, galactose. The presence of only one high-molecular fraction O-PS was a characteristic feature of all investigated strains. The predominant monosaccharides of O-PS were galactose, glucose, mannose, rhamnose and fucose. 3-hydroxytetradecanoic (48.9-93.1%), dodecanoic (2.9-12.1%), tetradecanoic (4.1-25.3%) and hexadecanoic (2.8-15.3%) acids have been obtained in lipids A of LPS depending on the strain. The presence in lipid A of R. aquatilis of only 3-hydroxytetradecanoic acid which is characteristic of Enterobacteriaceae proves the correct ascribing of the isolated strains to this family.

Three chlorotoluene-degrading bacterial strains: Differences in biodegradation potential and cell surface properties.

Pollution of the environment with chlorinated aromatic compounds is a problem of increasing importance, which has stimulated the search for efficient methods for the remediation of contaminated soil and water. Additionally, for better understanding of the significance of bioavailability to biodegradation, investigation of the cell surface properties is necessary. Hence, this study concerns the properties and possible application, in chlorotoluene removal, of three newly isolated environmental bacterial strains from the genera Pseudomonas, Raoultella and Rahnella. The results show the differences in the biochemical profiles of the isolated strains, their cellular fatty acid composition and their hemolytic properties. However, all three strains exhibit high biodegradation potential, degrading not less than 60% of each monochlorotoluene isomer in 21-day experiments. What is more, observations of changes in the cell surface properties indicate the possible adaptation mechanisms of the strains that enable efficient biodegradation of hydrophobic pollutants such as monochlorotoluenes.

Structure of the O-specific polysaccharide of the lipopolysaccharide of Rahnella aquatilis 95 U003.

The O-polysaccharide of Rahnella aquatilis 95 U003 was obtained by mild acid degradation of the lipopolysaccharide and studied by sugar and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, H-detected (1)H,(13)C HSQC and HMQC-TOCSY experiments. The O-polysaccharide was found to have a branched hexasaccharide repeating unit of the following structure: [carbohydrate structure: see text]

Structures of two putative O-specific polysaccharides from the Rahnella aquatilis 3-95 lipopolysaccharide.

Two polysaccharide preparations (OPSI and OPSII) were obtained by mild acid degradation of the lipopolysaccharide of Rahnella aquatilis 3-95. Studies by chemical methods and 1H and 13C NMR spectroscopy showed that OPSI is a linear alpha-D-mannan having a trisaccharide repeat and OPSII is a approximately 2:1 mixture of the same mannan and an alpha-d-glucan:

Antitumor activity of levan polysaccharides from selected microorganisms.

Levans were isolated from the cultures of Gluconoacetobacter xylinus (G-levan; Mw = 40,000), Microbacterium laevaniformans (M; Mw = 710,000), Rahnella aquatilis (R; Mw = 380,000), and Zymomonas mobilis (Z; Mw = 570,000). The levans were composed mainly of fructose residues when analyzed by TLC and HPLC, and their main backbones were beta-(2,6)-linkages with beta-(2,1)-branches by GC-MS and NMR. In the in vitro antitumor activity test of the levans against eight different tumor cell lines, relatively stronger activity was observed from the SNU-1 and HepG2. The M- (52.54-62.05%) and R-levan (52.15-58.58%) showed the significantly high activity against SNU-1, while M-levan showed the highest (49.93-61.82%) activity against HepG2. During the in vivo analysis of inhibitory activity of the levans against Sarcoma-180 growth, M-, R- and Z-levans showed strong antitumor activity (average 66%) but G-levan (42%) had significantly lower activity.

[Biological activity of native and modified lipopolysaccharides of Rahnella aquatilis]. / Biologicheskaia aktivnost' nativnykh i modifitsirovannykh lipopolisakharidov Rahnella aquatilis.

Modified lipopolysaccharide (LPS) preparations: dephosphorylated and N,O-dcacylated ones of six strains of Rahnella aquatilis have been obtained. It has been shown that the modified LPS, in contrast to native ones, have lost completely their toxicity and pathogenicity. This can evidence for the participation of both acyl, and phosphoryl groups in biological activity of LPS of R. aquatilis.

[Characteristics of structure components of Rahnella aquatilis lipopolysaccharides]. / Kharakteristika strukturnykh komponentov lipopolisakharidov Rahnella aquatilis.

LPS have been isolated from 6 strains of Rahnella aquatilis, their separate structure components have been obtained: lipid A, O-specific polysaccharide shain (OPS) and core oligosaccharide. 3-Oxytetradecanoic (31.7%) and tetradecanoic (17.8%) acids are dominating fatty acids of the lipid A. The core oligosaccharide of most investigated strains includes galactose and glucose, some of them include arabinose and ribose. Glucose, mannose and galactose are dominating monosaccharides in the composition of OPS of the strain 33071, fucose and galactose--in OPS of the strains 1-95, 2-95, 2-87 and 3-88, mannose in the composition of strain 3-95 OPS.

[Isolation and characterization of Rahnella aquatilis lipopolysaccharides]. / Vydelenie i kharakteristika lipopolisakharidov Rahnella aquatilis.

Lipopolysaccharides (LPS) of six strains of Rahnella aquatilis isolated from freshwater reservoirs, plant rhizosphere, and from patient have been investigated. It was shown, that LPS of type strain was characterized by the presence of rhamnose and mannose as predominant monosaccharides, while LPS of the rest strains contained galactose and fucose. The glucosamine content was insignificant (0.42-1.0%) in LPS of all strains studied. It was shown by double immunodiffusion in agar, immunoelectrophoresis and rocket immunoelectrophoresis that all R. aquatilis LPS were antigens in homological systems. The results of serological cross reactions evidence for immunochemical heterogeneity of R. aquatilis species. LPS of R. aquatilis display pyrogeneity and toxicity (LD50 from 0.20 to 0.33 mg/kg of experimental animals weight).

Isolation and structure elucidation of two different polysaccharides from the lipopolysaccharide of Rahnella aquatilis 33071T.

Two different polysaccharides were obtained by mild acid degradation of the lipopolysaccharide of Rahnella aquatilis 33071(T). These were studied by sugar and methylation analyses along with 1D and 2D (1)H and (13)C NMR spectroscopy. The following structures were established for the polysaccharides: -->4)-alpha-D-Rhap-(1-->3)-alpha-D-Rhap-(1-->3)beta-D-Galp-(1-->3)-alpha-D-Manp-(1-->2)-alpha-D-Manp-(1--> beta-D-Glcp-(1-->3)-alpha-D-galp-(1-->4)-alpha-D-GlcpA-(1-->2). The former structure is new, whereas the latter has been reported earlier as the structure of the O-specific polysaccharide of R. aquatilis 95 U003 (Zdorovenko, E. L.; Varbanets, L. D.; Zatonsky, G. V.; Kachala, V. V.; Zdorovenko, G. M.; Shashkov, A. S.; Knirel, Y. A. Carbohydr. Res.2008, 343, 2494-2497).

[Chemical characteristics and endotoxic activity of the lipopolysaccharide of Rahnella aquatilis 2-95].

The lipopolysaccharide (LPS) from a new Enterobacteriaceae species, Rahnella aquatilis 2-95, was isolated and investigated. The structural components of the LPS molecule, namely, lipid A, core oligosaccharide, and O-specific polysaccharide, were obtained by mild acid hydrolysis. In lipid A, 3-oxytetradecanoic and tetradecanoic acids were found to be the predominant fatty acids. The major monosaccharides of the core oligosaccharide were galactose, arabinose, fucose, rhamnose, and an unidentified component. The O-specific polysaccharide was found to be assembled of a repeated trisaccharide unit of the following structure: [structure: see text]. The R. aquatilis 2-95 LPS is less toxic and more pyrogenic as compared to the one from the R. aquatilis 1-95 strain studied earlier. Both acyl and phosphate groups are essential for toxic and pyrogenic activity of R. aquatilis 2-95 LPS.

[Characterization of the lipopolysaccharide from Rahnella aquatilis 1-95].

The lipopolysaccharide from the freshwater bacterium Rahnella aquatilis 1-95 has been isolated and investigated for the first time. The structural components of the lipopolysaccharide molecule: lipid A, core oligosaccharide, and O-specific polysaccharide were isolated by mild acidic hydrolysis. In lipid A, 3-hydroxytetradecanoic and tetradecanoic acids were found to be the predominant fatty acids. In the core oligosaccharide, galactose, arabinose, fucose, and an unidentified component were shown to be the major monosaccharides. The O-specific polysaccharide consists of a regularly repeating trisaccharide unit with the acyl and phosphate following structure: [structure: see text] groups have been shown to be responsible for the toxic and pyrogenic properties of the lipopolysaccharide of R. aquatilis.