Study on the presence of ochratoxin α in cultures of ochratoxigenic and non- ochratoxigenic strains of Aspergillus carbonarius

M Rosa Bragulat,Alba Eustaquio,F Javier Cabañes

doi:10.1371/journal.pone.0185986

M Rosa Bragulat, Alba Eustaquio + Show 1 more

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https://doi.org/10.1371/journal.pone.0185986

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Journal: PLOS ONE	Publication Date: Oct 10, 2017
Citations: 7	License type: CC BY 4.0

Affiliation: Autonomous University of Barcelona

Abstract

Ochratoxin A (OTA) is a potent nephrotoxin and carcinogen which is found in a wide variety of common foods and beverages and it is produced by several species of Aspergillus and Penicillium. Ochratoxin α (OTα), a major metabolite of OTA, has also been reported to occur in cultures of OTA-producing species. However there is some controversial about the participation of OTα in the biosynthesis of OTA, mainly because its biosynthesis pathway has not yet been completely characterized. Aspergillus carbonarius is the main responsible source of ochratoxin A (OTA) in food commodities such as wine, grapes or dried vine fruits from main viticultural regions worldwide. However, little is known about the presence of OTα in isolates of A. carbonarius. In this study we evaluated the effects of temperature and incubation time on OTα production by both OTA and non-OTA-producing strains of A. carbonarius. OTA and OTα were detected on the basis of HPLC fluorometric response compared with that of their standards and confirmed by HPLC-MS in selected samples. The non-OTA-producing strains did produce neither OTA nor OTα at any of the conditions tested. The OTA-producing strains studied were able to produce both OTA and OTα in most of the conditions tested. In general, higher amounts of OTA than OTα were produced, but a positive correlation in the production of these two metabolites was detected. The lack of production of both OTA and OTα in the non-OTA-producing strains could be caused by the presence of silent genes or by mutations in functional or regulatory genes involved in OTA production.

Highlights

Ochratoxin A (OTA) (N-[(3R)-(5-Chloro-8-hydroxy-3-methyl-1-oxo-7-isochromanyl) carbonyl]-L-phenylalanine) is a potent nephrotoxin and carcinogen which is found in a wide variety of common foods and beverages
As nothing is known about the culture conditions for Ochratoxin α (OTα) production by this species and it has not been clearly stated its participation in the biosynthesis of OTA, the aim of this study was to evaluate the effects of temperature and incubation time on OTα production by both OTA and non-OTA-producing strains of A. carbonarius
A total of 16 A. carbonarius strains were analyzed in order to know if they were able to produce OTA and/or OTα after 3, 10 or 30 days of incubation at 15, 25 and 30 ̊C

Summary

Introduction

Ochratoxin A (OTA) (N-[(3R)-(5-Chloro-8-hydroxy-3-methyl-1-oxo-7-isochromanyl) carbonyl]-L-phenylalanine) is a potent nephrotoxin and carcinogen which is found in a wide variety of common foods and beverages (e.g. cereals, coffee, dried fruits, grape juice, wine). Many other ochratoxigenic species of Aspergillus and of Penicillium have been characterized, few of them are known to contaminate foods with this mycotoxin Of these species, Aspergillus carbonarius is the main responsible source of OTA in food commodities such as wine, grapes or dried vine fruits from main viticultural regions worldwide [3]. Aspergillus carbonarius is the main responsible source of OTA in food commodities such as wine, grapes or dried vine fruits from main viticultural regions worldwide [3] This species is found in cocoa [4] and coffee beans [5] contaminated by OTA. Little is known about the presence of OTα in both OTA and nonOTA-producing isolates of A. carbonarius

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