Agglutination of Erwinia stewartii Strains with a Corn Agglutinin: Correlation with Extracellular Polysaccharide Production and Pathogenicity

摘要: Abstract A bacterial agglutinin was extracted from ground corn (WI hybrid 64A × W117) seed with phosphate-buffered saline (pH 6.0) and precipitated (NH4)2SO4 at 70% saturation. The activities of this against 22 strains Erwinia stewartii (agent wilt corn) that varied in virulence were determined. Specific agglutination (agglutination titer per milligram protein milliliter) values correlated negatively ratings. Strains high specific (15 or higher) avirulent weakly virulent; low (10 lower) highly virulent, two exceptions. Avirulent produced butyrous colonies released only small amounts extracellular polysaccharide (EPS) into the medium, cells lacked capsules; virulent fluidal large EPS, capsulated. There a strong correlation between amount EPS by each strain (as determined increase viscosity medium) value; contrast, lipopolysaccharide compositions similar all strains. When six washed repeatedly centrifuging resuspending them buffer, they agglutinated more strongly than unwashed cells. washed, their did not significantly. Eight EPS-deficient mutants E. stewartii, selected for resistance to capsule-dependent bacteriophage K9, had lower but higher corresponding wild-type parents. Production appears be essential virulence; may prevent bacteria host, thus allowing multiplication.