TY - JOUR
T1 - Killer toxin from several food-derived Debaryomyces hansenii strains effective against pathogenic Candida yeasts
AU - Banjara, Nabaraj
AU - Nickerson, Kenneth W.
AU - Suhr, Mallory J.
AU - Hallen-Adams, Heather E.
N1 - Funding Information:
This work was supported by the USDA National Institute of Food and Agriculture Hatch Project NEB-31-136 .
PY - 2016/4/2
Y1 - 2016/4/2
N2 - Candida yeasts are the dominant fungi in the healthy human microbiome, but are well-known for causing disease following a variety of perturbations. Evaluation of fungal populations from the healthy human gut revealed a significant negative correlation between the foodborne yeast, Debaryomyces hansenii, and Candida species. D. hansenii is reported to produce killer toxins (mycocins) effective against other yeast species. In order to better understand this phenomenon, a collection of 42 D. hansenii isolates was obtained from 22 cheeses and evaluated for killer activity against Candida albicans and Candida tropicalis over a range of temperatures and pH values. Twenty three strains demonstrated killer activity against both C. albicans and C. tropicalis, which was pH- and temperature-dependent, with no killer activity observed for any strain at pH. 6.5 or higher, or at ≥ 35 °C (physiological conditions in the human gastrointestinal tract). A cell-free mycocin preparation showed transient killer activity against C. albicans at 35. °C and a cheese sample containing a killer D. hansenii strain demonstrated sustained killer activity against both C. albicans and C. tropicalis. Together, these observations raise the possibility that D. hansenii could influence Candida populations in the gut.
AB - Candida yeasts are the dominant fungi in the healthy human microbiome, but are well-known for causing disease following a variety of perturbations. Evaluation of fungal populations from the healthy human gut revealed a significant negative correlation between the foodborne yeast, Debaryomyces hansenii, and Candida species. D. hansenii is reported to produce killer toxins (mycocins) effective against other yeast species. In order to better understand this phenomenon, a collection of 42 D. hansenii isolates was obtained from 22 cheeses and evaluated for killer activity against Candida albicans and Candida tropicalis over a range of temperatures and pH values. Twenty three strains demonstrated killer activity against both C. albicans and C. tropicalis, which was pH- and temperature-dependent, with no killer activity observed for any strain at pH. 6.5 or higher, or at ≥ 35 °C (physiological conditions in the human gastrointestinal tract). A cell-free mycocin preparation showed transient killer activity against C. albicans at 35. °C and a cheese sample containing a killer D. hansenii strain demonstrated sustained killer activity against both C. albicans and C. tropicalis. Together, these observations raise the possibility that D. hansenii could influence Candida populations in the gut.
KW - Cheese
KW - Killer yeast
KW - Microbiome
KW - Mycocin
KW - Probiotic
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U2 - 10.1016/j.ijfoodmicro.2016.01.016
DO - 10.1016/j.ijfoodmicro.2016.01.016
M3 - Article
C2 - 26828815
AN - SCOPUS:84961383291
VL - 222
SP - 23
EP - 29
JO - International Journal of Food Microbiology
JF - International Journal of Food Microbiology
SN - 0168-1605
ER -