TY - JOUR
T1 - Effects of zinc chelators on aflatoxin production in Aspergillus parasiticus
AU - Wee, Josephine
AU - Day, Devin M.
AU - Linz, John E.
N1 - Funding Information:
This work was supported by NIH grant CA 52003-21 (John E. Linz) and Michigan State University AgBio Research. The authors thank the Center for Advance Microscopy at Michigan State University for confocal microscopy images. We especially acknowledge Melinda Frame at the center for her assistance and helpful suggestions on confocal microscopy studies.
Publisher Copyright:
© 2016 by the authors; licensee MDPI, Basel, Switzerland.
PY - 2016/6
Y1 - 2016/6
N2 - Zinc concentrations strongly influence aflatoxin accumulation in laboratory media and in food and feed crops. The presence of zinc stimulates aflatoxin production, and the absence of zinc impedes toxin production. Initial studies that suggested a link between zinc and aflatoxin biosynthesis were presented in the 1970s. In the present study, we utilized two zinc chelators, N,N,Nʹ,Nʹ-tetrakis (2-pyridylmethyl) ethane-1,2-diamine (TPEN) and 2,3-dimercapto-1-propanesulfonic acid (DMPS) to explore the effect of zinc limitation on aflatoxin synthesis in Aspergillus parasiticus. TPEN but not DMPS decreased aflatoxin biosynthesis up to six-fold depending on whether A. parasiticus was grown on rich or minimal medium. Although we observed significant inhibition of aflatoxin production by TPEN, no detectable changes were observed in expression levels of the aflatoxin pathway gene ver-1 and the zinc binuclear cluster transcription factor, AflR. Treatment of growing A. parasiticus solid culture with a fluorescent zinc probe demonstrated an increase in intracellular zinc levels assessed by increases in fluorescent intensity of cultures treated with TPEN compared to controls. These data suggest that TPEN binds to cytoplasmic zinc therefore limiting fungal access to zinc. To investigate the efficacy of TPEN on food and feed crops, we found that TPEN effectively decreases aflatoxin accumulation on peanut medium but not in a sunflower seeds-derived medium. From an application perspective, these data provide the basis for biological differences that exist in the efficacy of different zinc chelators in various food and feed crops frequently contaminated by aflatoxin.
AB - Zinc concentrations strongly influence aflatoxin accumulation in laboratory media and in food and feed crops. The presence of zinc stimulates aflatoxin production, and the absence of zinc impedes toxin production. Initial studies that suggested a link between zinc and aflatoxin biosynthesis were presented in the 1970s. In the present study, we utilized two zinc chelators, N,N,Nʹ,Nʹ-tetrakis (2-pyridylmethyl) ethane-1,2-diamine (TPEN) and 2,3-dimercapto-1-propanesulfonic acid (DMPS) to explore the effect of zinc limitation on aflatoxin synthesis in Aspergillus parasiticus. TPEN but not DMPS decreased aflatoxin biosynthesis up to six-fold depending on whether A. parasiticus was grown on rich or minimal medium. Although we observed significant inhibition of aflatoxin production by TPEN, no detectable changes were observed in expression levels of the aflatoxin pathway gene ver-1 and the zinc binuclear cluster transcription factor, AflR. Treatment of growing A. parasiticus solid culture with a fluorescent zinc probe demonstrated an increase in intracellular zinc levels assessed by increases in fluorescent intensity of cultures treated with TPEN compared to controls. These data suggest that TPEN binds to cytoplasmic zinc therefore limiting fungal access to zinc. To investigate the efficacy of TPEN on food and feed crops, we found that TPEN effectively decreases aflatoxin accumulation on peanut medium but not in a sunflower seeds-derived medium. From an application perspective, these data provide the basis for biological differences that exist in the efficacy of different zinc chelators in various food and feed crops frequently contaminated by aflatoxin.
UR - http://www.scopus.com/inward/record.url?scp=84973457801&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84973457801&partnerID=8YFLogxK
U2 - 10.3390/toxins8060171
DO - 10.3390/toxins8060171
M3 - Article
C2 - 27271668
AN - SCOPUS:84973457801
SN - 2072-6651
VL - 8
JO - Toxins
JF - Toxins
IS - 6
M1 - 171
ER -