Stimulation of the production of neuraminidase in Vibrio cholerae cultures by N-acetylneuraminic acid and sialyl-lactose.

Abstract

SUMMARY: A simple medium is described which allows adequate growth of Vibrio cholerae with the production of only trace amounts of neuraminidase. When added to this medium to give a final concentration of 600 μ m, sialyl lactose or sialyl-N- acetylgalactosamine, two oligosaccharides which contain ketosidically bound N-acetylneuraminic acid and which are substrates of neuraminidase, caused at least a 100-fold increase in the amount of neuraminidase produced during growth of the organisms. N-Acetylneuraminic acid was also found to stimulate neuraminidase production. Galactose and N-acetylgalactosamine had no effect. N-Acetylneura- minic acid was metabolized by V. cholerae as indicated by the disappearance from such enriched medium of substances giving the direct Ehrlich reaction. Evidence is presented which suggests that neuraminidase is an extracellular enzyme.