Structural studies of the O polysaccharides from the lipopolysaccharides of Azospirillum thiophilum BV-ST and Azospirillum griseum L-25-5w-1T.

Diazotrophic bacteria of the genus Azospirillum are known widely, because they are ubiquitous in the rhizosphere and can promote the growth and performance of nonlegume plants. Recently, more Azospirillum species have been isolated from sources other than plants or soil. We report the structures of the O polysaccharides (OPSs) from the lipopolysaccharides of the type strains A. thiophilum BV-ST (1) and A. griseum L-25-5w-1T (2), isolated from aquatic environments. Both structures have a common tetrarhamnan in the repeating-unit, which is decorated with a side xylose in the OPS of A. thiophilum BV-ST.

Structure, Physicochemical Properties and Biological Activity of Lipopolysaccharide from the Rhizospheric Bacterium Ochrobactrum quorumnocens T1Kr02, Containing d-Fucose Residues.

Lipopolysaccharides (LPSs) are major components of the outer membranes of Gram-negative bacteria. In this work, the structure of the O-polysaccharide of Ochrobactrum quorumnocens T1Kr02 was identified by nuclear magnetic resonance (NMR), and the physical-chemical properties and biological activity of LPS were also investigated. The NMR analysis showed that the O-polysaccharide has the following structure: →2)-ß-d-Fucf-(1→3)-ß-d-Fucp-(1→. The structure of the periplasmic glucan coextracted with LPS was established by NMR spectroscopy and chemical methods: →2)-ß-d-Glcp-(1→. Non-stoichiometric modifications were identified in both polysaccharides: 50% of d-fucofuranose residues at position 3 were O-acetylated, and 15% of d-Glcp residues at position 6 were linked with succinate. This is the first report of a polysaccharide containing both d-fucopyranose and d-fucofuranose residues. The fatty acid analysis of the LPS showed the prevalence of 3-hydroxytetradecanoic, hexadecenoic, octadecenoic, lactobacillic, and 27-hydroxyoctacosanoic acids. The dynamic light scattering demonstrated that LPS (in an aqueous solution) formed supramolecular particles with a size of 72.2 nm and a zeta-potential of -21.5 mV. The LPS solution (10 mkg/mL) promoted the growth of potato microplants under in vitro conditions. Thus, LPS of O. quorumnocens T1Kr02 can be recommended as a promoter for plants and as a source of biotechnological production of d-fucose.

Lipopolysaccharides of Herbaspirillum species and their relevance for bacterium-host interactions.

The lipopolysaccharides of Herbaspirillum lusitanum P6-12T (HlP6-12T) and H. frisingense GSF30T (HfGSF30T) was isolated by phenol-water extraction from bacterial cells and was characterized using chemical analysis and SDS-PAGE. It was shown that these bacteria produce LPSs that differ in their physicochemical properties and macromolecular organization. In this paper, the lipid A structure of the HlP6-12T LPS, was characterized through chemical analyses and matrix-assisted laser desorption ionization (MALDI) mass spectrometry. To prove the effect of the size of micelles on their bioavailability, we examined the activity of both LPSs toward the morphology of wheat seedlings. Analysis of the HlP6-12T and HfGSF30T genomes showed no significant differences between the operons that encode proteins involved in the biosynthesis of the lipids A and core oligosaccharides. The difference may be due to the composition of the O-antigen operon. HfGSF30T has two copies of the rfb operon, with the main one divided into two fragments. In contrast, the HlP6-12T genome contains only a single rfb-containing operon, and the other O-antigen operons are not comparable at all. The integrity of O-antigen-related genes may also affect LPS variability of. Specifically, we have observed a hairpin structure in the middle of the O-antigen glycosyltransferase gene, which led to the division of the gene into two fragments, resulting in incorrect protein synthesis and potential abnormalities in O-antigen production.

Structure of the O-specific polysaccharide of Ochrobactrum endophyticum KCTC 42485T containing 3-(3-hydroxy-2,3-dimethyl-5-oxoprolyl)amino-3,6-dideoxy-d-galactose.

Ochrobactrum endophyticum (syn. Brucella endophytica) is an aerobic species of Alphaproteobacteria isolated from healthy roots of Glycyrrhiza uralensis. Here we report the structure of the O-specific polysaccharide obtained by mild acid hydrolysis of the lipopolysaccharide of the type strain KCTC 42485:→3)-α-l-FucpNAc-(1→3)-ß-d-QuipNAc-(1→2)-ß-d-Fucp3NAcyl-(1→ where Acyl is 3-hydroxy-2,3-dimethyl-5-oxoprolyl. The structure was elucidated using chemical analyses along with 1H and 13C NMR spectroscopy (including 1H,1H COSY, TOCSY, ROESY and 1H,13C HSQC, HMBC, HSQC-TOCSY and HSQC-NOESY experiments). To our knowledge the OPS structure is novel and has not been previously published.

Fourier Transform Infrared (FTIR) Spectroscopic Study of Biofilms Formed by the Rhizobacterium Azospirillum baldaniorum Sp245: Aspects of Methodology and Matrix Composition.

Biofilms represent the main mode of existence of bacteria and play very significant roles in many industrial, medical and agricultural fields. Analysis of biofilms is a challenging task owing to their sophisticated composition, heterogeneity and variability. In this study, biofilms formed by the rhizobacterium Azospirillum baldaniorum (strain Sp245), isolated biofilm matrix and its macrocomponents have for the first time been studied in detail, using Fourier transform infrared (FTIR) spectroscopy, with a special emphasis on the methodology. The accompanying novel data of comparative chemical analyses of the biofilm matrix, its fractions and lipopolysaccharide isolated from the outer membrane of the cells of this strain, as well as their electrophoretic analyses (SDS-PAGE) have been found to be in good agreement with the FTIR spectroscopic results.

Structure and antiproliferative activity of the polysaccharide from Halomonas aquamarina related to Cobetia pacifica.

Here, the results of the structure and the activity of capsular polysaccharides isolated from the Halomonas aquamarina EG27S8QL and Cobetia pacifica KMM3878 have been described. Both polysaccharides were studied by spectroscopic and chemical methods and were found to be structurally related sulfated galactans differing in the position of the sulfate group: →6)-ß-D-Galp3S-(1 â†’ 4)-ß-D-Galp3S-(1 â†’ 6)-ß-D-Galp3,4(S-Pyr)-(1 â†’ [H. aquamarina EG27S8QL] →6)-ß-D-Gal-(1 â†’ 4)-ß-D-Gal2,3S-(1 â†’ 6)-ß-D-Gal3,4(S-Pyr)-(1 â†’ [C. pacifica KMM3878] Structure of the CPS from H. aquamarina EG27S8QL has not been hitherto reported, whereas the CPS from C. pacifica KMM3878 was identical to the previously studied O-polysaccharide. The CPSs exhibited an antiproliferative effect and suppressed the colony formation of DLD-1 and MCF-7 cells in a different manner.

Whole-cell electric sensor for determination of sodium dodecyl sulfate.

Linear alkyl sulfates are a major class of surfactants that have large-scale industrial application and thus wide environmental release. These organic pollutants threaten aquatic environments and other environmental compartments. We show the promise of the use of a whole-cell electric sensor in the analysis of low or residual concentrations of sodium dodecyl sulfate (SDS) in aqueous solutions. On the basis of bioinformatic analysis and alkylsulfatase activity determinations, we chose the gram-negative bacterium Herbaspirillum lusitanum, strain P6-12, as the sensing element. Strain P6-12 could utilize 0.01-400 mg/L of SDS as a growth substrate. The electric polarizability of cell suspensions changed at all frequencies used (50-3000 kHz). The determination limit of 0.01 mg/L is much lower than the official requirements for the content of SDS in potable and process water (0.5 and 1.0 mg/L, respectively), and the analysis takes about 1-5 min. The promise of H. lusitanum P6-12 for use in the remediation of SDS-polluted soils is discussed.

Structure of the 4-O-[1-Carboxyethyl]-d-Mannose-Containing O-Specific Polysaccharide of a Halophilic Bacterium Salinivibrio sp. EG9S8QL.

The moderately halophilic strain Salinivibrio sp. EG9S8QL was isolated among 11 halophilic strains from saline mud (Emisal Salt Company, Lake Qarun, Fayoum, Egypt). The lipopolysaccharide was extracted from dried cells of Salinivibrio sp. EG9S8QL by the phenol-water procedure. The OPS was obtained by mild acid hydrolysis of the lipopolysaccharide and was studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments. The OPS was found to be composed of linear tetrasaccharide repeating units of the following structure: →2)-ß-Manp4Lac-(1→3)-α-ManpNAc-(1→3)-ß-Rhap-(1→4)-α-GlcpNAc-(1→, where Manp4Lac is 4-O-[1-carboxyethyl]mannose.

Structure of the O-specific polysaccharide from Azospirillum formosense CC-Nfb-7(T).

The lipopolysaccharide was obtained from the cells of Azospirillum formosense CC-Nfb-7(T), a diazotrophic bacterium isolated from agricultural soil. The O-specific polysaccharide (OPS) was released by mild acid hydrolysis of the lipopolysaccharide and was studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments, and Smith degradation. The following structure of partially methylated OPS composed of trisaccharide repeating units was established.

Structural and genetic characterization of the colitose-containing O-specific polysaccharide from the lipopolysaccharide of Herbaspirillum frisingense GSF30T.

The lipopolysaccharide (LPS) of Herbaspirillum frisingense GSF30T (HfGSF30), a non-pathogenic diazotrophic endobiont, was isolated by phenol-water extraction from bacterial cells and was characterized by chemical analyses and SDS PAGE. The O-specific polysaccharide (OPS, O-antigen), obtained by mild acid hydrolysis of the LPS, was examined by sugar and methylation analysis, along with 1H and 13C NMR spectroscopy, including 2D 1H,1H COSY, 1H,1H TOCSY, 1H,1H ROESY, 1H,13C HSQC, and 1H,13C HMBC experiments. The OPS was found to consist of branched tetrasaccharide repeating units of the following structure: [Formula: see text] This structure is unique among the known bacterial polysaccharide structures. Analysis of the HfGSF30 genome showed that it contained a set of sequentially arranged operons (presumably a cluster of genes) associated with the O-antigen. Amino acid sequence analysis using the BLAST program demonstrated the specificity of this putative cluster for Herbaspirillum spp. The genes responsible for the biosynthesis of the OPS of HfGSF30 were dispersed in the genome, constituting small operons. A putative O-antigen gene cluster of HfGSF30 was identified and found to be consistent with the OPS structure.

Isolation, structure, and potential biotechnological applications of the exopolysaccharide from Paenibacillus polymyxa 92.

Paenibacillus polymyxa 92, isolated from wheat roots, produced large amounts (38.4 g L-1) of exopolysaccharide (EPS) in a liquid nutrient medium containing 10 % (w/v) sucrose. The EPS was precipitated from the culture broth with cold acetone and was purified by gel filtration and anion-exchange chromatography. The molecular mass of the EPS was 2.29-1.10 × 105 Da. Diffuse reflectance infrared Fourier transform and nuclear magnetic resonance spectra showed that the EPS was a linear ß-(2→6)-linked fructan (levan). Aqueous EPS solutions showed pseudoplastic behavior when shear stress was applied at different temperatures. By using the Ostwald-de Waele model, the rheological characteristics of the EPS solution were ascertained. The sorption capacity of the EPS for Zn(II), Cd(II), Pb(II), and Cu(II) was investigated. Sorption was maximal (q = 481 mg g-1) for Cu(II) ions. In model experiments, treatment of wheat seeds with EPS solution significantly increased the length of seedling roots and shoots.

Bioremediation potential of a halophilic Halobacillus sp. strain, EG1HP4QL: exopolysaccharide production, crude oil degradation, and heavy metal tolerance.

A halophilic bacterial strain, EG1HP4QL, was isolated from a salt sample from Lake Qarun, Fayoum Province, Egypt. Morphological, physiological, biochemical, and phylogenetic analyses indicated that the strain belonged to the genus Halobacillus. Strain EG1HP4QL produced an extracellular polysaccharide (EPS), with production peaking (5.9 g L-1) during growth on medium S-G containing 2% (w/v) sucrose at 35 °C (pH 8.0). The EPS had significant emulsifying activity (E24 %) against kerosene (65.7 ± 0.8%), o-xylene (64.0 ± 1%), and sunflower oil (44.7 ± 0.5%). The composition of the EPS included two polymers-a negatively charged and a neutral one (~ 3:1)-in which mannose and glucose were the main neutral monosaccharide constituents. Strain EG1HP4QL was able to utilize crude oil (35.3%) as the sole carbon source within 12 days. The minimum inhibitory concentrations of heavy metals [Zn(II), Cd(II), Pb(II), Ni(II), and Cu(II)] for strain EG1HP4QL were 1.0, 2.0, 2.0, 2.5, and 5 mM, respectively.

Structure of the O-specific polysaccharide from a halophilic bacterium Halomonas ventosae RU5S2EL.

Halomonas ventosae RU5S2EL, a halophilic Gram-negative bacterium isolated from salt sediments of lake Elton (Russia), was cultivated and the lipopolysaccharide was extracted by the Westphal procedure. The O-specific polysaccharide (OPS) was obtained by mild acid hydrolysis of the lipopolysaccharide and was studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments as well as Smith degradation. The OPS was found to consist of branched pentasaccharide repeating units of the following structure.

Immunochemical characterization of the capsular polysaccharide of Azospirillum irakense KBC1.

The repeating unit structure of Azospirillum irakense KBC1 capsular polysaccharide (CPS) was established and was found to be identical to that of the O polysaccharide of A. irakense KBC1 lipopolysaccharide (LPS). The antigenic heterogeneity of the LPS and the CPS was shown to be related to differences in the macromolecular organization of these glycopolymers. After an immune response activation, R-form CPS molecules were found to be predominant.

An improved rapid method for the preparation of D-rhamnose.

A method is developed for the preparation of D-rhamnose from an O-polysaccharide (OPS) isolated by mild acid hydrolysis of Azospirillum brasilense SR75 cell mass. After the OPS hydrolysis, D-rhamnose was recovered by gel-permeation chromatography on Toyopearl TSK HW-40 and was crystallized. The sugar activity was demonstrated immunochemically. The advantages of the method are that it expedites and simplifies the extraction of D-rhamnose and increases its yield.

Structural and functional peculiarities of the lipopolysaccharide of Azospirillum brasilense SR55, isolated from the roots of Triticum durum.

Azospirillum brasilense SR55, isolated from the rhizosphere of Triticum durum, was classified as serogroup II on the basis of serological tests. Such serogroup affiliation is uncharacteristic of wheat-associated Azospirillum species. The lipid A of A. brasilense SR55 lipopolysaccharide contained 3-hydroxytetradecanoic, 3-hydroxyhexadecanoic, hexadecanoic and octadecenoic fatty acids. The structure of the lipopolysaccharide's O polysaccharide was established, with the branched octasaccharide repeating unit being represented by l-rhamnose, l-3-O-Me-rhamnose, d-galactose and d-glucuronic acid. The SR55 lipopolysaccharide induced deformations of wheat root hairs. The lipopolysaccharide was not involved in bacterial cell aggregation, but its use to pretreat wheat roots was conducive to cell adsorption. This study shows that Azospirillum bacteria can utilise their own lipopolysaccharide as a carbon source, which may give them an advantage in competitive natural environments.