Alternate interactions of the D-galactose-specific yeast lectin Kb-CWL I with sensitive yeast strains.

In vitro growth assays with a purified D-galactose-specific lectin Kb-CWL I extracted from Kluyveromyces bulgaricus showed marked antifungal effects on 9 of 12 test strains belonging to the genera Kluyveromyces, Saccharomyces, Pichia, Candida, Rhodotorula and Schizosaccharomyces. The inhibition of growth was proportional to the lectin concentration (0.04 and 0.08 mg ml-1) in the culture medium. Under the test conditions, K. bulgaricus, K. lactis and S. bayanus were consistently agglutinated without growth inhibition. D-Galactose, the inhibitory sugar of the cell aggregation activity, did not abolish the antifungal effects of the lectin Kb-CWL I on other yeast strains tested. In C. albicans and C. tropicalis, the lectin influenced the dimorphism of these strains and stimulated germ tube formation.