Degradation of ochratoxin a and b by the white rot funguspleurotus ostreatus

Engelhardt, G.

doi:10.1007/bf02946138

Cited by 26 publications

(17 citation statements)

References 10 publications

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“…5). The massive accumulation of OT␤ could also be due to the degradation of OTB largely increased in fungal cultures, which could be a possible target of the same proteolytic enzyme that catalyzes the degradation of OTA into OT␣ (31,32). Within the panel of metabolites analyzed by HPLC-HRMS, OTC and OTB ethyl ester were not detected in the cultures of both ⌬kusA and ⌬kusA ⌬AcOTAhal mutant strains, confirming that these metabolites should not be involved in the OTA biosynthesis pathway as already observed (12).…”

Section: Discussionmentioning

confidence: 99%

Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius

Ferrara

Perrone

Gambacorta

et al. 2016

Appl Environ Microbiol

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Aspergillus carbonarius is the main responsible fungus of ochratoxin A (OTA) contamination of grapes and derived products. To date, the biosynthetic mechanism of this mycotoxin has been partially elucidated. Availability of genome sequence of A. carbonarius has allowed the identification of a putative gene cluster involved in OTA biosynthesis. This region hosts the previously characterized AcOTAnrps and AcOTApks genes encoding two key enzymes of the biosynthetic pathway. At about 4,400 nucleotides downstream of these loci, a gene encoding a putative flavin dependent-halogenase came out from the annotation data. Its proximity to OTA biosynthetic genes and its sequence analysis have suggested a role in the biosynthesis of OTA, directed to the introduction of the chlorine atom in the C-5 position of the final molecular structure of this mycotoxin. The deduced protein sequence of the halogenase gene, we designated AcOTAhal, shows a high similarity to a halogenase that is located in the OTA cluster of A. niger. The deletion of the halogenase gene completely eliminated the production of ochratoxin A in A. carbonarius and determined a significant increase of ochratoxin B, as confirmed by mass spectrometry analysis. Moreover, its expression profile was similar to the two biosynthetic genes previously identified, AcOTApks and AcOTAnrps, indicating a strong correlation of the AcOTAhal gene with the kinetics of OTA accumulation in A. carbonarius. Therefore, experimental evidence confirmed that the chlorination step which converts OTB in OTA represents the final stage of the biosynthetic pathway, supporting our earlier hypothesis on the order of enzymatic steps of OTA biosynthesis in A. carbonarius. IMPORTANCEOchratoxin A is a potent mycotoxin classified as a possible carcinogen for humans, and Aspergillus carbonarius is the main agent responsible for OTA accumulation in grapes. We demonstrate here that a flavin-halogenase is implicated in the biosynthesis of OTA in A. carbonarius. The encoding gene, AcOTAhal, is contiguous to biosynthetic genes that we have already described (nrps and pks), resulting as part of the biosynthetic cluster. The encoded protein is responsible of the introduction of chlorine atom in the final molecular structure and acts at the last step in the pathway. This study can be considered a continuation of an earlier study wherein we started to clarify the molecular basis of OTA biosynthesis in A. carbonarius, which has not been completely elucidated until now. This research represents an important step forward to a better understanding of the production mechanism, which will contribute to the development of improved control strategies to reduce the risk of OTA contamination in food products.

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Section: Discussionmentioning

confidence: 99%

Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius

Ferrara

Perrone

Gambacorta

et al. 2016

Appl Environ Microbiol

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“…[85], Aspergillus spp. [86,87,88,89], Pleurotus ostreatus [90] and Trichosporon [91]). Among microbial populations involved in food production, especially those involved in beer brewing [92,93,94] or yoghurt production (e.g., Streptococcus salivarius , Lactobacillus delbruecki [95]) have been shown to degrade OTA to some extent.…”

Section: Degradation Of Ochratoxin a In Ruminantsmentioning

confidence: 99%

Ochratoxin A in Ruminants–A Review on Its Degradation by Gut Microbes and Effects on Animals

Mobashar

Hummel

Blank

et al. 2010

Toxins

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Ruminants are much less sensitive to ochratoxin A (OTA) than non-ruminants. The ruminal microbes, with protozoa being a central group, degrade the mycotoxin extensively, with disappearance half lives of 0.6–3.8 h. However, in some studies OTA was detected systemically when using sensitive analytical methods, probably due to some rumen bypass at proportions of estimated 2–6.5% of dosage (maximum 10%). High concentrate proportions and high feeding levels are dietary factors promoting the likeliness of systemic occurrence due to factors like shifts in microbial population and higher contamination potential. Among risk scenarios for ruminants, chronic intoxication represents the most relevant.

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“…Other filametous fungus Rhizopus stolonifer variety stolonifer TJM 8A8 could degrade 96.5% of OTA in wheat while A. niger CBS 120.49 was not able to degrade OTA in wheat (Varga et al 2005). Only 23% of the initial OTA amount were detected after the incubation of barley with Pleurotus ostreatus (Engelhardt 2002). It has been suggested that a carboxypeptidase enzyme is responsible for the conversion of OTA to OTα (Bejaoui et al 2006;Péteri et al 2007).…”

Section: Ochratoxin a Detoxification And Inhibition Of Ochratoxin A Amentioning

confidence: 99%

Prevention of ochratoxin A contamination of foodand ochratoxin A detoxification by microorganisms - a review

Cicoňová¹,

Laciakova²,

Máté³

2010

Czech J. Food Sci.

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Cicoňová P., Laciaková A., Máté D. (2010): Prevention of ochratoxin A contamination of food and ochratoxin A detoxification by microorganisms -a review. Czech J. Food Sci., 28: 465-474.Ochratoxin A is a mycotoxin produced by several fungal species of the genera Aspergillus and Penicillium. This mycotoxin is nephrotoxic, immunosupressive, teratogeni, and carcinogenic to animals and has been classified as a possible human carcinogen. Human exposure to ochratoxin A is worldwide. Ochratoxin A occurs in a variety of foods. An ideal method for minimisation of the health risk that this mycotoxin poses is the prevention of food contamination. When the contamination occurs, the hazard associated with the mycotoxin presence in the food must be eliminated. Various microorganisms such as bacteria and microscopic fungi have been tested for their abilities to prevent ochratoxin A contamination or detoxify foods. Biological control by microorganisms is studied widely, therefore the objective of this article is to provide an overview of the recent development in the biological control of ochratoxin A contamination.

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Degradation of ochratoxin a and b by the white rot funguspleurotus ostreatus

Cited by 26 publications

References 10 publications

Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius

Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius

Ochratoxin A in Ruminants–A Review on Its Degradation by Gut Microbes and Effects on Animals

Prevention of ochratoxin A contamination of foodand ochratoxin A detoxification by microorganisms - a review

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