Phosphatidylinositol as a Component of the Ice Nucleating Site of Pseudomonas syringae and Erwinia herbiola
LLOYD M. KOZLOFF 1,
MURL LUTE 1, and
DAVID WESTAWAY 1
1 Department of Microbiology, University of California, San Francisco 94143
Phosphatidylinositol has been identified as a major component of the ice nucleating site on the outer surface of two bacteria, Pseudomonas syringae and Erwinia herbicola. Plant lectins binding to inositol and a highly purified phosphatidylinositol-specific hydrolase (a CII lipase) inhibited or decreased the efficiency of the ice nucleating activity (INA) of both bacteria. Extracts of these two INA+ bacteria had phosphatidylinositol synthase activity while extracts from related INA- Pseudomonas or Erwinia strains had no detectable synthase activity. An Escherichia coli strain acquired phosphatidylinositol synthase activity when transformed to the INA+ phenotype with recombinant plasmids containing fragments of P. syringae DNA.
Submitted on June 18, 1984
Accepted on August 21, 1984
