Characteristics of Killer Toxin of the Yeast Cryptococcus pinus

Abstract

This work was aimed to study of fungicidal activity and mechanism of action of the killer toxin of Cryptococcus pinus VKM Y-2958. A killer-toxin preparation was obtained and partly purified from the culture liquid of the yeast Cryptococcus pinus. Its fungicidal activity against the pathogenic yeast Filobasidiella neoformans was assessed by assay of target cells growth inhibition and propidium iodide staining. The preparation contained three peptides with molecular masses of about 11 - 13 kDa, which did not show similarities in the mass spectrometric analysis. When frozen, the killer-toxin preparation remained active for several years. The killer toxin of Cr. pinus exhibits the high fungicidal activity against the known pathogen F. neoformans, is stable during long-term storage, and its mechanism of action is based on damaging target cell membranes. The killer toxin was obtained by a simple procedure and is of interest for the development of novel fungicidal preparations.