Date of Award
Master of Science (MS)
The lipopolysaccharides (LPSs) of the Rhizobium phaseoli CE3 and its mutants CE109, CE309 and the transconjugate Rhizobium leguminosarum LB2/109.11 were isolated and analyzed by gas chromatography (GC) and 1H nuclear magnetic resonance (NMR) spectroscopy. CE3 is the wild type strain which is nodulation-proficient (Nod+). Strain CE109 and CE309 have a transposon, Tn5, inserted into Region I and Region III of their respetive chromosomes. Mutants CE109 and CE309 are defective in nodule development (Ndv-). Transconjugate R. leg. LB2/109.11 has the DNA of the R. leg. LB2 wild type and also Region I portion of the CE109 where the Tn5 is inserted. This mutant is Nod+on peas.
Mild acid hydrolysis of the LPSs gives a precipitate (lipid A) and supernatant (O-antigen and core polysaccharides). In the separation of the supernatant components by Bio-Gel P2 column, three peaks are detected, LPS-P2-1, LPS-P2-2 and LPS-P2-3. The first peak corresponds to the O-antigen and the others two are the components of the core. The GC analysis of the LPSs shows that the mutant CE109 and CE309 lack the O-antigen; in contrast, LB2/109.11 has sugars corresponding to the O-antigens from both parent strains, CE3 and LB2. Both LPS-P2-2 and LPS-P2-3 are altered in GalA content for CE109 and only LPS-P2-2 is altered, lacking Gal and GalA, for CE309. These core components from LB2/109.11 are the same as those from CE3.
Garcia, Francisca, "Characterization of the Lipopolysaccharides from Rhizobium phaseoli Symbiotic Mutants" (1988). Masters Theses. 2540.
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