Killer yeast
[4] Study of killer toxins helped to better understand the secretion pathway of yeast, which is similar to those of more complex eukaryotes.
In S. cerevisiae are toxins encoded by a double-stranded RNA virus, translated to a precursor protein, cleaved and secreted outside of the cells, where they may affect susceptible yeast.
[10] The initial protein product from translation of the M dsRNA is called the preprotoxin, which is targeted to the yeast secretory pathway.
[11][12] K28 uses the α-1,6-mannoprotein receptor to enter the cell, and utilizes the secretory pathway in reverse by displaying the endoplasmic reticulum HDEL signal.
Sesti, Shih, Nikolaeva and Goldstein (2001) claimed that K1 inhibits the TOK1 membrane potassium channel before secretion, and although the toxin reenters through the cell wall it is unable to reactivate TOK1.
[2] Killer properties of Kluyveromyces lactis are associated with linear DNA plasmids, which have on their 5'end associated proteins, which enable them to replicate themselves, in a way similar to adenoviruses.
Palpacelli, Ciani and Rosini (1991) found that Kluyveromyces phaffii was effective against Kloeckera apiculata, Saccharomycodes ludwigii and Zygosaccharomyces rouxii – all of which cause problems in the food industry.
[23] Lowes et al. (2000) created a synthetic gene for the toxin HMK normally produced by Williopsis mrakii, which they inserted into Aspergillus niger and showed that the engineered strain could control aerobic spoilage in maize silage and yoghurt.
[25] A toxin produced by Candida nodaensis was effective at preventing spoilage of highly salted food by yeasts.
[26] Several experiments suggest that antibodies that mimic the biological activity of killer toxins have application as antifungal agents.
The toxin of Saccharomyces cerevisiae and Pichia kluyveri inhibited Dekkera anomala accumulating methylene blue cells on Yeast Extract Peptone Dextrose agar (pH 4.2) at 21°C.
There was no inhibition of growth or competition between the yeast cells in the mixed population of S. cerevisiae isolated from Acalypha indica.
