Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Mesorhizobium loti

Sortuj według:

Ogranicz wyniki do:

Localization of the attachment site of oligoglucans to Mesorhizobium loti HAMBI 1148 murein

100%

Karas M., Russa R.

Acta Biochimica Polonica

2009

tom 56

nr 1

155-160

The location and nature of the linkage between peptidoglycan and oligoglucans in the cell wall of Mesorhizobium loti HAMBI 1148 have been defined by the analysis of nitrous acid deamination of peptidoglycan glucosaminyl residues. The MurNH2-Glcn fraction was obtained after converting deaminoacylated and N-deacetylated muramyl residues in the cell wall preparation to lactam forms which were stable during subsequent deamination, followed by reduction and opening of the lactams. GC/MS analysis of this material, subjected to partial hydrolysis and reduction or to methanolysis followed by peracetylation, confirmed the presence of glucosyl residues glycosidically attached to muramic acid. The MALDI-TOF spectroscopic analysis of the deaminated material also revealed the presence of [M-H]- or [M+Na-2H]- ions representing fragments containing muramic acid with one to three linked glucose residues. The analysis of fully methylated neutral oligosaccharides released from the peptidoglycan with lysozyme followed by borohydride reduction showed the presence of di- and trisaccharides lacking the reducing end.

Alteration of O-specific polysaccharide structure of symbiotically defective Mesorhizobium loti mutant 2213.1 derived from strain NZP2213

80%

Turska-Szewczuk A., Pietras H., Borucki W., Russa R.

Acta Biochimica Polonica

2008

tom 55

nr 1

Mesorhizobium loti mutant 2213.1 derived from the wild-type strain NZP2213 by Tn5 mutagenesis showed impaired effectiveness of symbiosis with the host plant Lotus corniculatus (Turska-Szewczuk et al., 2007 Microbiol Res, in press). The inability of lipopolysaccharide (LPS) isolated from the mutant 2213.1 strain or de-O-acetylated LPS of the parental cells to inactivate phage A1 particles implicated alterations in the LPS structure. The O-specific polysaccharide of the mutant was studied by chemical analyses along with 1H and 13C NMR spectroscopy, which clearly confirmed alterations in the O-chain structure. 2D NMR data showed that the mutant O-polysaccharide consists of a tetrasaccharide repeating unit containing non-substituted as well as O-acetylated or O-methylated 6-deoxytalopyranose residues. Additionally, an immunogold assay revealed a reduced number of gold particles on the mutant bacteroid cell surface, which could result from both a diminished amount of an O-antigenic determinant in mutant LPS and modifications of structural epitopes caused by alterations in O-acetylation or O-methylation of sugar residues. Western immunoblot assay of alkaline de-O-acetylated lipophilic M. loti NZP2213 LPS showed no reactivity with homologous serum indicating a role of O-acetyl groups in its O-specificity.

Ograniczanie wyników

2 Acta Biochimica Polonica

2 Russa R.

1 Borucki W.

1 Karas M.

1 Pietras H.

1 Turska-Szewczuk A.

1 2009

1 2008

Wyniki wyszukiwania

Localization of the attachment site of oligoglucans to Mesorhizobium loti HAMBI 1148 murein

Alteration of O-specific polysaccharide structure of symbiotically defective Mesorhizobium loti mutant 2213.1 derived from strain NZP2213