Antigenic bacterial polysaccharides. 13. The structure of the O-specific polysaccharide chain of the lipopolysaccharide from Pseudomonas cepacia strain IMV 4137

On mild acid degradation of a lipopolysaccharide from Pseudomonas cepacia strain IMV 4137, a serologically active O-specific polysaccharide was obtained and shown to contain L-rhamnose and D-galactose. According to 1H- and 13C-NMR data as well as methylation analysis, the polysaccharide is made up of disaccharide repeating units of the following structure:----2)-alpha-L-Rhap-(1----4)-alpha-D-Galp-(1----.     

Somatic antigens of Pseudomonas aeruginosa. The structure of the O-specific polysaccharide chains of lipopolysaccharides of P. aeruginosa serogroup O4 (Lányi) and related serotype O6 (Habs) and immunotype 1 (Fisher)

Acidic O-specific polysaccharides were isolated on mild acidic degradation of lipopolysaccharides of Pseudomonas aeruginosa serotypes O4a,b, O4a,c, O4a,d (Lányi classification) and serologically related to them serotype O6 (Habs classification) and immunotype 1 (Fisher classification). The polysaccharides had identical monosaccharide composition and were built up of L-rhamnose, 2-acetamido-2,6-dideoxy-D-glucose,2-formamido-2-deoxy-D-galacturonic acid and 2-acetamido-2-deoxy-D-galactouronamide residues. The latter two derivatives of D-galactosaminuronic acid were found in nature for the first time. All the polysaccharides, but Lányi serotype O4a,c, contained O-acetyl groups. The polysaccharides were readily de-O-acetylated with aqueous triethylamine and de-N-formylated with dilute hydrochloric acid. De-N-formylated polysaccharide of serotype O4a,c was selectively cleaved with nitrous acid upon 2-amino-2-deoxygalacturonic acid residues to form a tetrasaccharide with a 2,5-anhydrotaluronic acid residue on the reducing end. The tetrasaccharide represented a modified repeating unit of the polysaccharide. Solvolysis of all intact polysaccharides with hydrogen fluoride selectively split the glycosidic linkages of 6-deoxy sugars to give the same trisaccharide, including both derivatives of galactosaminuronic acid and having 2-acetamido-2,6-dideoxyglucose on the reducing end. Structural investigation of the oligosaccharides obtained together with methylation analysis and 13C nuclear magnetic resonance data revealed the following structures of the O-specific polysaccharides: (Formula: see text) An independent confirmation of the structures of the repeating units was obtained as the result of full interpretation of the 13C nuclear magnetic resonance spectra of the intact and modified polymers. Spectral data analysis revealed a number of regularities in the effects of glycosidation connecting their values with the anomeric and absolute configuration of pyranose residues. The data on the structures of the O-specific polysaccharides indicated that each of the five P. aeruginosa strains under study should be considered as an individual O-serotype within one O-serogroup.     

Cell-wall lipopolysaccharide of the 'Shigella-like' Escherichia coli 058. Structure of the polysaccharide chain.

Two lipopolysaccharide preparations were obtained from Escherichia coli 058 by extraction with 45% aqueous phenol and fractional precipitation with cetyltrimethyl ammonium bromide (Cetavlon). Chemical analysis and polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate showed that the two preparations differed only in the extent of the O-specific polysaccharide moiety. The O-specific polysaccharide was characterized with proton magnetic resonance and infrared spectroscopy, optical rotation and paper electrophoresis. Using gas-liquid chromatography and ion-exchange chromatography, it was shown to contain D-mannose, 2-acetamido-2-deoxy-D-glucose, 3-O-(R-1'-carboxyethyl)-L-rhamnose (rhamnolactylic acid), and O-acetyl groups in the molar ratios of 2:1:1:1. The polysaccharide and oligosaccharides obtained from it were subjected to methylation and chromic acid oxidation. The results obtained indicated that the polysaccharide consists of tetrasaccharide repeating units in which the trisaccharide beta-GlcNAc1 - 4alphaMan-1 - 4(2/3-O-Ac)-Man is substituted at C-3 of the non-acetylated mannose with rhamnolactylic acid. The repeating units are joined through alpha-mannosyl-1 - 3-glucosamine bonds. This structure is identical with that of the cell wall polysaccharide of Shigella dysenteriae type 5.     

Effect of naphthalene biodegradation plasmids on physiological characteristics of rhizospheric bacteria of the genus Pseudomonas

Specific growth rate, duration of the lag phase, stability of plasmids, and activities of the key enzymes involved in naphthalene biodegradation were studied in rhizospheric pseudomonades carrying structurally similar plasmids pOV17 and pBS216. It was demonstrated that these plasmids determined various levels of catechol 2,3-dioxygenase activities. The structural rearrangements in the plasmid pBS216 could "switch off" the genes of catechol oxidation meta-pathway. It was shown that certain combinations of biodegradation plasmids and bacterial hosts, such as Pseudomonas chlororaphis PCL1391(pBS216), P. chlororaphis PCL1391(pOV17), and P. putida 53a(pOV17), were considerably more efficient than natural variants in their growth characteristics and stability of the biodegradation activity, having a potential for bioremediation of soils polluted with polycyclic aromatic hydrocarbons (PAHs).     

Fractal properies of gating in potential-dependent K+-channels in Lymnaea stagnalis neurons

Sets of the channel open times, [tau(o)], and closed times, [tau(c)], and the full set of the channel open and closed times, [tau(o), tau(c)], in the activity of single voltage-dependent K+-channels in mollusc L. stagnalis neurons were analyzed using the rescaled range analysis (Hurst method), fast Fourier and wavelet transforms. It was found that the Hurst dependence for each time series could be approximated by a polygonal line with at least two slopes: H1 and H2 (Hurst exponents). The averaged values of H1 and H2 for the sets [tau(o), tau(c)] were equal to 0.61 +/- 0.03 and 0.83 +/- 0.11, respectively; for the [tau(o)] sets H1 = 0.66 +/- 0.03 and H2 = 0.95 +/- 0.10; for the [tau(c)] sets, H1 = 0.62 +/- 0.05 and H2 = 0.85 +/- 0.10. In some cases, a third slope appeared on the Hurst dependences. It was very variable and ranged between 0.5 and 1. The Hurst exponents H1, H2, and H3 characterized short, intermediate, and long time ranges, respectively. The ranges greatly varied from experiment to experiment. The data obtained show that the channel openings and closings (gating process) represent a persistent process correlated in time. The randomization of the time sets resulted in a single slope, H, of 0.52 +/- 0.02 characteristic of random processes. The results were confirmed by the fast Fourier and wavelet transforms. In addition, possible voltage dependences of Hurst exponents and their correlation with tau(o) and tau(c) were investigated. As a whole, single channel activity may be characterized as a multifractal process with a slight voltage dependence of the Hurst exponents.     

Biodegradation of phenanthrene by Pseudomonas bacteria bearing rhizospheric plasmids in model plant-microbial associations

The consumption phenanthrene in soil by model plant-microbial associations including natural and transconjugant plasmid-bearing rhizospheric strains of Pseudomonas fluorescens and P. aureofaciens degrading polycyclic aromatic hydrocarbons was studied. It was shown that phytoremediation of soil polluted with phenanthrene in the rhizosphere of barley (Hordeum sativum L.) was inefficient with the absence of the degrading strains. Inoculation of barley seeds with both natural and transconjugant plasmid-bearing Pseudomonas strains able to degrade polycyclic aromatic hydrocarbons (PAH) protected plants from the phytotoxic action of phenanthrene and favored its degradation in soil. Rape (Brassica napus L.) was shown to be an appropriate sentinel plant, sensitive to phenanthrene, which can be used for testing the efficiency of phenanthrene degradation in soil. The biological test with the use of sensitive rape plants can be applied for estimation of the efficiency of phyto/bioremediation of PAH-polluted soils.     

A computer-assisted structural analysis of regular polysaccharides on the basis of 13C-n.m.r. data

A computerised approach to the structural analysis of unbranched regular polysaccharides is described, which is based on an evaluation of the 13C-n.m.r. spectra for all possible primary structures within the additive scheme starting from the chemical shifts of the 13C resonances of the constituent monosaccharides and the average values of the glycosylation effects. The analysis reveals a structure (or structures), the evaluated spectrum of which resembles most closely that observed. The approach has been verified by using a series of bacterial polysaccharides of known structure and, in combination with methylation analysis data, for the determination of the presently unknown structures of the O-specific polysaccharides from Salmonella arizonae O59 and O63, and Proteus hauseri O19.