Structure of the Escherichia coli 0104 polysaccharide and its identity with the capsular K9 polysaccharide |
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Authors: | Grigorij Kogan Barbara Jann Klaus Jann |
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Affiliation: | Department of Bacteriology and Biochemistry, University of Idaho, Moscow 83843. |
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Abstract: | Spontaneous mutants of Rhizobium leguminosarum biovar viciae strain C1204b were selected for their ability to tolerate 0.2 M NaCl, a growth-inhibiting level of salt for the parental strain. Transposon-mediated salt-sensitive mutants of strain C1204b were screened for their inability to grow in 0.08 M NaCl. Quantitation of the free-amino acid pools in the mutants grown in NaCl revealed a dramatic increase in glutamine, serine, glutamate and proline, and to a lesser extent alanine and glycine in the salt-tolerant mutants in comparison with the parental strain exposed to NaCl; but only glutamate and proline increased in the salt-sensitive mutants under NaCl stress. Extracellular polysaccharide levels were quantitated for the salt-tolerant mutants and determined to be approximately two-fold higher than for the parental strain. Although the mutations that occurred in the NaCl-tolerant and NaCl-sensitive strains did not interfere with nodule formation, no nitrogenase activity could be observed in the NaCl tolerant mutants as evaluated by acetylene reduction. |
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Keywords: | Escherichia coli Lipopolysaccharide Capsular polysaccharide N-Acethylneuraminic acid |
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