Exopolysaccharide production by nitrogen-fixing bacteria within nodules of Medicago plants exposed to chronic radiation in the Chernobyl exclusion zone.
Nitrogen-fixing bacteria isolated from root nodules of Medicago plants growing in the 10 km zone around the Chernobyl nuclear power plant were screened for the production of new water-soluble acidic exopolysaccharides (EPSs). The different strains belonged to the Enteriobacteriaceae family (Enterobacter ludwigii, Raoultella terrigena, Klebsiella oxytoca), except for one which belonged to the Rhizobiaceae family (Sinorhizobium meliloti). All of the bacteria produced highly viscous EPS with an average molecular weight comprised between 1 x 10(6) and 3 x 10(6) Da. Five different compositions of EPS were characterized by physico-chemical analyses and (1)H NMR spectroscopy: galactose/mannose (2/1), galactose/glucose (1/1), galactose/glucose/mannose (1/2/1), fucose/galactose/glucose (2/1/1) and fucose/galactose/glucose/mannose (2/2/1/1 or 1/1/2/4). Glucuronic acid, a charged monosaccharide, was also recovered in most of the different EPSs.
Pawlicki-Jullian
Nathalie
N
Laboratoire des Polysaccharides Microbiens et végétaux, IUT Dpt GB, 80025 Amiens, France. nathalie.jullian@u-picardie.fr
Courtois
Bernard
B
Pillon
Michelle
M
Lesur
David
D
Le Flèche-Mateos
Anne
A
Laberche
Jean-Claude
JC
Goncharova
Nadia
N
Courtois
Josiane
J
D047852:Chernobyl Nuclear Accident; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004755:Enterobacteriaceae / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D005643:Fucose / Q000032:analysis; D005690:Galactose / Q000032:analysis; D005947:Glucose / Q000032:analysis; D020723:Glucuronic Acid / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000032:analysis; D029902:Medicago / Q000382:microbiology* / Q000528:radiation effects; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism*; D002094:Republic of Belarus; D053204:Root Nodules, Plant / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D016962:Sinorhizobium meliloti / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects
D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; D005643:Fucose; D020723:Glucuronic Acid; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D005947:Glucose; D008358:Mannose; D005690:Galactose