Chemical characterization of effective and ineffective strains of Rhizobium leguminosarum bv. viciae

Chemical composition of lipopolysaccharide (LPS) isolated from an effective (97) and ineffective (87) strains of R. l. viciae has been determined. LPS preparations from the two strains contained: glucose, galactose, mannose, fucose, arabinose, heptose, glucosamine, galactosamine, quinovosamine, and 3-N-methyl-3,6-dideoxyhexose, as well as glucuronic, galacturonic and 3-deo xyoctulosonic acid. The following fatty acids were identified: 3-OH 14:0, 3 -OH 15:0, 3-OH 16:0, 3-OH 18:0 and 27-OH 28:0. The ratio of 3-OH 14:0 to ot her major fatty acids in LPS 87 was higher that in LPS 97. SDS/PAGE profile s of LPS indicated that, in lipopolysaccharides, relative content of S form LPS I to that of lower molecular mass (LPS II) was much higher in the effe ctive strain 97 than in 87. All types of polysaccharides exo-, capsular-, l ipo, (EPS, CPS, LPS, respectively) examined possessed the ability to bind f aba bean lectin. The degree of affinity of the host lectin to LPS 87 was ha lf that to LPS 97. Fatty acids (FA) composition from bacteroids and peribac teroid membrane (PBM) was determined. Palmitic, stearic and hexadecenoic ac ids were common components found in both strains. There was a high content of unsaturated fatty acids in bacteroids as well as in PBM lipids. The unsa turation index in the PBM formed by strain 87 was lower than in the case of strain 97. Higher ratio of 16:0 to 18:1 fatty acids was characteristic for PMB of the ineffective strain.