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Aspergillus carbonarius

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P V Martinezculebras – 1st expert on this subject based on the ideXlab platform

  • effect of oxidant stressors and phenolic antioxidants on the ochratoxigenic fungus Aspergillus carbonarius
    Journal of the Science of Food and Agriculture, 2016
    Co-Authors: P V Martinezculebras, Luis Gonzalezcandelas, Ana Cresposempere, Cristina Selmalazaro, Jeffrey D Palumbo

    Abstract:

    BACKGROUND

    There are few studies dealing with the relationship between oxidative stress and ochratoxin A (OTA) biosynthesis. In this work, we analyzed the effect of the oxidant stressor menadione and the antioxidants 3,5-di-tert-butyl-4-hydroxytoluene (BHT), catechin, resveratrol and a polyphenolic extract on growth, generation of reactive oxygen species (ROS), OTA production and gene expression of antioxidant enzymes of Aspergillus carbonarius.

    RESULTS

    Exposure to menadione concentrations higher than 20 µmol L−1 led to increases in ROS and OTA levels and a decrease in growth rate. Exposure to 2.5–10 mmol L−1 BHT also led to higher ROS and OTA levels, although growth rate was only affected above 5 mmol L−1. Naturally occurring concentrations of catechin, resveratrol and polyphenolic extract barely affected growth rate, but they produced widely different effects on OTA production level depending on the antioxidant concentration used. In general, gene expression of antioxidant enzymes superoxide dismutase (SOD) and peroxiredoxin (PRX) was downregulated after exposure to oxidant and antioxidant concentrations that enhanced OTA production level.

    CONCLUSION

    Aspergillus carbonarius responds to oxidative stress, increasing OTA production. Nevertheless, the use of naturally occurring concentrations of antioxidant phenolic compounds to reduce oxidative stress is not a valid approach by itself for OTA contamination control in grapes. © 2015 Society of Chemical Industry

  • the loss of the inducible Aspergillus carbonarius mfs transporter mfsa leads to ochratoxin a overproduction
    International Journal of Food Microbiology, 2014
    Co-Authors: A Cresposempere, P V Martinezculebras, Luis Gonzalezcandelas

    Abstract:

    Ochratoxin A (OTA), a nephrotoxic compound produced by certain Aspergillus and Penicillium species, is one of the most abundant mycotoxins in food commodities. Aspergillus carbonarius is the main source of OTA in wine, grape juice and dried vine fruits. Although many studies have focused on OTA production by A. carbonarius, little is known about the genes related to OTA production and transport. We have found a transporter that belongs to the major facilitator superfamily (MfsA) which is highly expressed with a 102-fold induction in an ochratoxigenic A. carbonarius strain compared to a low OTA producer strain. The encoding mfsA gene shows similarity to the multidrug efflux transporter flu1 from Candida albicans. A high number of putative transcription factor binding sites involved in the response to stress were identified within the promoter of mfsA. Phenotypical analysis of ΔmfsA deletion mutants revealed that the loss of mfsA leads to a slight growth reduction and increased OTA production. We therefore hypothesize that MfsA could be a stress response transporter whose disruption could cause an increase in oxidative stress together with a stimulation of mycotoxin production.

  • characterization and disruption of the cipc gene in the ochratoxigenic fungus Aspergillus carbonarius
    Food Research International, 2013
    Co-Authors: A Cresposempere, P V Martinezculebras, Cristina Selmalazaro, Luis Gonzalezcandelas

    Abstract:

    Abstract Aspergillus carbonarius is considered the most important ochratoxin A (OTA) producing fungi among those causing OTA contamination in grapes and grape-derived products. CipC is a small protein with unknown function that was previously found to be highly up-regulated in an OTA producer strain of A. carbonarius in comparison to a non OTA producer strain. In this study, cipC was characterized and disrupted via Agrobacterium tumefaciens-mediated transformation in an ochratoxigenic A. carbonarius strain in order to study whether this gene has a role in OTA production. Sequence analysis indicated that the promoter region of cipC contains putative binding sites for transcription factors that regulate the utilization of nutrients, the stress response and detoxification processes, all factors that can influence mycotoxin biosynthesis. Although the ∆cipC mutant grew similarly to the wild type strain, the null mutant showed a much higher OTA production. Moreover, when A. carbonarius was grown under the oxidative stress conditions imposed by the presence of hydrogen peroxide, cipC gene expression was up-regulated. These results indicate that cipC is not directly involved in OTA biosynthesis, but sequence analysis of the A. carbonarius cipC gene promoter and the phenotype of the ΔcipC disrupted mutant suggests that CipC could be a stress response protein that would be up-regulated concomitantly with OTA production.

A Cresposempere – 2nd expert on this subject based on the ideXlab platform

  • the loss of the inducible Aspergillus carbonarius mfs transporter mfsa leads to ochratoxin a overproduction
    International Journal of Food Microbiology, 2014
    Co-Authors: A Cresposempere, P V Martinezculebras, Luis Gonzalezcandelas

    Abstract:

    Ochratoxin A (OTA), a nephrotoxic compound produced by certain Aspergillus and Penicillium species, is one of the most abundant mycotoxins in food commodities. Aspergillus carbonarius is the main source of OTA in wine, grape juice and dried vine fruits. Although many studies have focused on OTA production by A. carbonarius, little is known about the genes related to OTA production and transport. We have found a transporter that belongs to the major facilitator superfamily (MfsA) which is highly expressed with a 102-fold induction in an ochratoxigenic A. carbonarius strain compared to a low OTA producer strain. The encoding mfsA gene shows similarity to the multidrug efflux transporter flu1 from Candida albicans. A high number of putative transcription factor binding sites involved in the response to stress were identified within the promoter of mfsA. Phenotypical analysis of ΔmfsA deletion mutants revealed that the loss of mfsA leads to a slight growth reduction and increased OTA production. We therefore hypothesize that MfsA could be a stress response transporter whose disruption could cause an increase in oxidative stress together with a stimulation of mycotoxin production.

  • ecophysiological characterization of Aspergillus carbonarius Aspergillus tubingensis and Aspergillus niger isolated from grapes in spanish vineyards
    International Journal of Food Microbiology, 2014
    Co-Authors: Esther Garciacela, A Cresposempere, V Sanchis, Antonio J Ramos, Sonia Marin

    Abstract:

    abstract Article history:Received 10 September 2013Received in revised form 25 November 2013Accepted 12 December 2013Available online 21 December 2013Keywords:Climate conditionsProbabilistic modelsMicrosatellitesOchratoxin ABlack aspergilli The aim of this study was to evaluate the diversity of black aspergilli isolated from berries from differentagroclimatic regions of Spain. Growth characterization( interms of temperature and water activity requirements)of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger was carried out on synthetic grape medium.A.tubingensis andA.niger showedhighermaximumtemperaturesforgrowth( N45 °Cversus40–42 °C),andlowerminimuma w requirements(0.83 a w versus 0.87 a w )thanA.carbonarius.Nodifferencesingrowthboundariesdueto their geographical origin were found within A. niger aggregate isolates. Conversely, A. carbonarius isolates fromthe hotter and drier region grew and produced OTA at lower a w than other isolates. However, little genetic diver-sityin A.carbonarius wasobservedforthemicrosatellitestestedandthesamesequenceofβ-tubulingenewasob-served;thereforeintraspecificvariabilitydidnotcorrelatewiththegeographicaloriginoftheisolatesorwiththeirabilitytoproduceOTA.Climaticchangepredictionpointstodrierandhotterclimaticscenarioswhere A.tubingensisand A. niger couldbeevenmoreprevalentoverA. carbonarius, since theyare betteradaptedto extremehigh tem-perature and drier conditions.© 2013 Elsevier B.V. All rights reserved.

  • characterization and disruption of the cipc gene in the ochratoxigenic fungus Aspergillus carbonarius
    Food Research International, 2013
    Co-Authors: A Cresposempere, P V Martinezculebras, Cristina Selmalazaro, Luis Gonzalezcandelas

    Abstract:

    Abstract Aspergillus carbonarius is considered the most important ochratoxin A (OTA) producing fungi among those causing OTA contamination in grapes and grape-derived products. CipC is a small protein with unknown function that was previously found to be highly up-regulated in an OTA producer strain of A. carbonarius in comparison to a non OTA producer strain. In this study, cipC was characterized and disrupted via Agrobacterium tumefaciens-mediated transformation in an ochratoxigenic A. carbonarius strain in order to study whether this gene has a role in OTA production. Sequence analysis indicated that the promoter region of cipC contains putative binding sites for transcription factors that regulate the utilization of nutrients, the stress response and detoxification processes, all factors that can influence mycotoxin biosynthesis. Although the ∆cipC mutant grew similarly to the wild type strain, the null mutant showed a much higher OTA production. Moreover, when A. carbonarius was grown under the oxidative stress conditions imposed by the presence of hydrogen peroxide, cipC gene expression was up-regulated. These results indicate that cipC is not directly involved in OTA biosynthesis, but sequence analysis of the A. carbonarius cipC gene promoter and the phenotype of the ΔcipC disrupted mutant suggests that CipC could be a stress response protein that would be up-regulated concomitantly with OTA production.

Sonia Marin – 3rd expert on this subject based on the ideXlab platform

  • ecophysiological characterization of Aspergillus carbonarius Aspergillus tubingensis and Aspergillus niger isolated from grapes in spanish vineyards
    International Journal of Food Microbiology, 2014
    Co-Authors: Esther Garciacela, A Cresposempere, V Sanchis, Antonio J Ramos, Sonia Marin

    Abstract:

    abstract Article history:Received 10 September 2013Received in revised form 25 November 2013Accepted 12 December 2013Available online 21 December 2013Keywords:Climate conditionsProbabilistic modelsMicrosatellitesOchratoxin ABlack aspergilli The aim of this study was to evaluate the diversity of black aspergilli isolated from berries from differentagroclimatic regions of Spain. Growth characterization( interms of temperature and water activity requirements)of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger was carried out on synthetic grape medium.A.tubingensis andA.niger showedhighermaximumtemperaturesforgrowth( N45 °Cversus40–42 °C),andlowerminimuma w requirements(0.83 a w versus 0.87 a w )thanA.carbonarius.Nodifferencesingrowthboundariesdueto their geographical origin were found within A. niger aggregate isolates. Conversely, A. carbonarius isolates fromthe hotter and drier region grew and produced OTA at lower a w than other isolates. However, little genetic diver-sityin A.carbonarius wasobservedforthemicrosatellitestestedandthesamesequenceofβ-tubulingenewasob-served;thereforeintraspecificvariabilitydidnotcorrelatewiththegeographicaloriginoftheisolatesorwiththeirabilitytoproduceOTA.Climaticchangepredictionpointstodrierandhotterclimaticscenarioswhere A.tubingensisand A. niger couldbeevenmoreprevalentoverA. carbonarius, since theyare betteradaptedto extremehigh tem-perature and drier conditions.© 2013 Elsevier B.V. All rights reserved.

  • alternating temperatures and photoperiod effects on fungal growth and ochratoxin a production by Aspergillus carbonarius isolated from tunisian grapes
    International Journal of Food Microbiology, 2010
    Co-Authors: Souheib Oueslati, Salma Lasram, Sonia Marin, A J Ramos, V Sanchis, Ahmed Mliki, Abdelwahed Ghorbel

    Abstract:

    Abstract The effect of three alternating temperatures cycles (20/30, 20/37 and 25/42 °C) and photoperiod on growth and Ochratoxin A (OTA) production of six isolates of Aspergillus carbonarius on synthetic nutrient medium were investigated. The different temperature regimes affected significantly both the mycelial growth and the OTA production. The best growth and OTA production were recorded at 20/30 °C. The isolates from the region of Baddar produced the highest OTA yields. A 24 h light cycle generally enhanced the growth of A. carbonarius . Growth rates cycles of 11 h/13 h light/darkness and 24 h darkness were often similar for individual isolates, such conditions enhanced OTA production in two of the six isolates tested.

  • kinetics and spatial distribution of ota in Aspergillus carbonarius cultures
    Food Microbiology, 2006
    Co-Authors: Ana Valero, V Sanchis, A J Ramos, Joan Farre, Sonia Marin

    Abstract:

    Abstract The aim of this study was to characterize Ochratoxin A (OTA) production by Aspergillus carbonarius under different environmental conditions, and to elucidate the diffusion capacity of OTA throughout synthetic medium. One strain belonging to the species A. carbonarius isolated from vine dried fruit was single-point inoculated onto triplicate synthetic nutrient medium plates at two water activities (0.92 and 0.97) and two temperatures (20 and 30 °C). Daily radii were measured and OTA production was tested after 4, 7, 10, 14 and 18 days of incubation at four distances from the centre of colony (1–4 cm). OTA production was detected mainly at 0.97 a w . Earlier production was detected at 30 °C (optimum for growth), whereas maximum OTA concentrations were found at 20 °C. OTA production was detected from mycelium that was only a few days old and attained its optimum when mycelium was 4–7 days old at 0.97 a w . OTA diffusion was observed at 0.92 a w and 20 °C. Thus OTA production is discernable in young A. carbonarius mycelium and diffusion of the toxin has been shown to occur in a solid substrate.