Elucidation of a masked repeating structure of the O-specific polysaccharide of the halotolerant soil bacteria Azospirillum halopraeferens Au4

Abstract

SummaryAn O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide isolated by the phenol–water extraction from the halotolerant soil bacteria Azospirillum halopraeferens type strain Au4. The polysaccharide was studied by sugar and methylation analyses, selective cleavages by Smith degradation and solvolysis with trifluoroacetic acid, one- and two-dimensional 1H and 13C NMR spectroscopy. The following masked repeating structure of the O-specific polysaccharide was established: →3)-α-L-Rhap2Me-(1→3)-[β-D-Glcp-(1→4)]-α-D-Fucp-(1→2)-β-D-Xylp-(1→, where non-stoichiometric substituents, an O-methyl group (~45%) and a side-chain glucose residue (~65%), are shown in italics.

Lipopolysaccharide O-antigen molecular and supramolecular modifications of plant root microbiota are pivotal for host recognition

“…Likewise, Arabidopsis responses to Herbaspirillum LPS includes acetylated O-antigen recognition as a nonpathogenic signal, followed by the subsequent downregulation of defense-related immune responses. This is in agreement with the particular role and the peculiar chemistry of LPS in rhizobia where it serves to dampen the immune response and contribute establishment of a successful symbiosis (Sigida 2016;Silipo, 2011;Turska-Szewczuk, 2009;. However, a shielding strategy based on LPS chemistry can be used by pathogen bacteria to tune and revert their immune recognition.…”

Molecular Characterization and Biocompatibility of Exopolysaccharide Produced by Moderately Halophilic Bacterium Virgibacillus dokdonensis from the Saltern of Kumta Coast

“…Additionally, chemical shift patterns of 1 H and 13 C indicate that glucose and xylose exist in both α- and β-configurations as independent repeating units. The observed proton chemical shifts of monosaccharide residues of VITP14 EPS are consistent with the EPS reported in the literature [ 71 , 72 , 73 , 74 , 75 ]. The α-configuration of residues A and B and the β-configuration of residues C , D , D′, and E were confirmed based on the chemical shifts.…”

Synthesis of the tetrasaccharide repeating unit of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71T using linear and one-pot iterative glycosylations

“…Therefore, it is quite pertinent to study the effect of the cell-wall polysaccharides of rhizobacteria on the growth of leguminous plants. As a consequence, the structural elucidation of a variety of cell-wall polysaccharides of several strains of Azospirillum have been reported in the past [ 14 – 19 ]. However, detailed biological studies to understand the biochemical role of cell-wall polysaccharides require significant quantities of the polysaccharides with adequate purity, which are difficult to achieve through isolation from the natural sources.…”