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Jens Christian Frisvad - One of the best experts on this subject based on the ideXlab platform.
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occurrence and Fumonisin B2 producing potential of aspergillus section nigri in brazil nuts
Mycotoxin Research, 2017Co-Authors: Larissa De Souza Ferranti, Jens Christian Frisvad, Benedito Correa, Maria Helena Pelegrinelli Fungaro, Beatriz T Iamanaka, Fernanda Pelisson Massi, Christopher Phippen, Marta Hiromi TaniwakiAbstract:Bertholletia excelsa is the tree that produces Brazil nuts which have vast economic importance in the Amazon region and as an export commodity. The aim of this study was to assess the presence of Aspergillus section Nigri in Brazil nut samples at different stages of its production chain and to verify the toxigenic potential for Fumonisin B2 (FB2) production of these isolates along with the presence of this mycotoxin in Brazil nut samples. The fungal infection ranged from 0 to 80% at the different stages of the harvest and processing chain and the water activity of the nuts from 0.273 to 0.994. A total of 1052 A. section Nigri strains were isolated from Brazil nuts and 200 strains were tested for their ability to produce FB2: 41 strains (20.5%) were FB2 producers with concentrations ranging from 0.09 to 37.25 mg/kg; 2 strains (1%) showed traces of FB2, less than the detection limit (0.08 mg/kg); and 157 (78.5%) were not FB2 producers. Although several samples showed high contamination by A. section Nigri, no sample was contaminated by FB2.
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production of Fumonisin B2 and b4 by aspergillus niger on grapes and raisins
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Jesper Molgaard Mogensen, Jens Christian Frisvad, Ulf Thrane, Kristian Fog NielsenAbstract:The recent discovery of Fumonisin production in Aspergillus niger, raises concerns about the presence of these mycotoxins in grapes and raisins as well as other commodities where A. niger is a frequent contaminant. Here we investigate the potential production of Fumonisins in A. niger cultured on grapes and raisins. Sixty-six A. niger, 4 A. tubingensis, and 16 A. acidus strains isolated from raisins were tested for Fumonisin production on laboratory media. Neither A. tubingensis nor A. acidus strains produced Fumonisins, but 77% of A. niger strains did. None of the strains produced ochratoxin A. Ten selected Fumonisin producing A. niger strains were further able to produce Fumonisin B2 and Fumonisin B4 on grapes in the range 171−7841 μg Fumonisin B2/kg and 14−1157 μg Fumonisin B4/kg. Four selected strains were able to produce Fumonisin B2 (5−6476 μg/kg) and Fumonisin B4 (12−672 μg/kg) on raisins.
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isolation and nmr characterization of Fumonisin B2 and a new Fumonisin b6 from aspergillus niger
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Maria Mansson, Jens Christian Frisvad, Kristian Fog Nielsen, Marie Louise Klejnstrup, Richard Kerry Phipps, Charlotte Held Gotfredsen, Thomas Ostenfeld LarsenAbstract:A new Fumonisin, Fumonisin B6 (1), has been isolated by cation-exchange and reverse-phase chromatography, together with Fumonisin B2 (2), from stationary cultures of the fungus Aspergillus niger NRRL 326. Analysis of mass spectrometric and NMR data determined that FB6 is a positional isomer of FB1 and iso-FB1, having hydroxyl functions at C3, C4, and C5. Analysis of the NMR data for FB2 showed very similar chemical shift values when compared to an authentic Fusarium FB2 standard, strongly indicating identical molecules despite that an absolute stereochemical assignment of FB2 from A. niger was not possible.
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Effect of temperature and water activity on the production of Fumonisins by Aspergillus niger and different Fusarium species.
BMC Microbiology, 2009Co-Authors: Jesper Molgaard Mogensen, Jens Christian Frisvad, Robert A Samson, Kristian Fog Nielsen, Ulf ThraneAbstract:Background Fumonisins are economically important mycotoxins which until recently were considered to originate from only a few Fusarium species. However recently a putative Fumonisin gene cluster was discovered in two different Aspergillus niger strains followed by detection of an actual Fumonisin B2 (FB2) production in four strains of this biotechnologically important workhorse.
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proteome analysis of aspergillus niger lactate added in starch containing medium can increase production of the mycotoxin Fumonisin B2 by modifying acetyl coa metabolism
BMC Microbiology, 2009Co-Authors: Rene Lametsch, Louise Marie Sorensen, Mikael Rordam Andersen, Per Vaeggemose Nielsen, Jens Christian FrisvadAbstract:Background Aspergillus niger is a filamentous fungus found in the environment, on foods and feeds and is used as host for production of organic acids, enzymes and proteins. The mycotoxin Fumonisin B2 was recently found to be produced by A. niger and hence very little is known about production and regulation of this metabolite. Proteome analysis was used with the purpose to reveal how Fumonisin B2 production by A. niger is influenced by starch and lactate in the medium.
Thomas Reinard - One of the best experts on this subject based on the ideXlab platform.
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Production of a single-chain variable fragment antibody against Fumonisin B1.
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Björn Lauer, Ilka Ottleben, Hans Jörg Jacobsen, Thomas ReinardAbstract:The selection of synthetic antibody fragments from large phage libraries has become a common method for the generation of specific antibodies. The technique is particularly valuable when antibodies against small, non-immunogenic molecules (haptens) or highly toxic substances have to be produced. In addition, haptens are usually coupled to protein carriers, bearing the risk that the free hapten is not detectable. Here, a single variable chain antibody (scFv) against the highly toxic mycotoxin Fumonisin B1 has been produced. The hapten was coupled via a linker to biotin. Using this conjugate and a naive scFv library, it was possible to circumvent both the necessity of immunization and the risk of a disguised hapten. The scFv obtained after three panning rounds was found to bind specifically to both free Fumonisin B1 and Fumonisin−biotin conjugate. Also Fumonisin B2 was bound by the scFv. Modeling of both scFv and Fumonisin B1 molecule revealed a good fitting of structures. The antibody obtained can potentia...
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Production of a single-chain variable fragment antibody against Fumonisin B1
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Björn Lauer, Ilka Ottleben, Hans Jörg Jacobsen, Thomas ReinardAbstract:The selection of synthetic antibody fragments from large phage libraries has become a common method for the generation of specific antibodies. The technique is particularly valuable when antibodies against small, non-immunogenic molecules (haptens) or highly toxic substances have to be produced. In addition, haptens are usually coupled to protein carriers, bearing the risk that the free hapten is not detectable. Here, a single variable chain antibody (scFv) against the highly toxic mycotoxin Fumonisin B1 has been produced. The hapten was coupled via a linker to biotin. Using this conjugate and a naive scFv library, it was possible to circumvent both the necessity of immunization and the risk of a disguised hapten. The scFv obtained after three panning rounds was found to bind specifically to both free Fumonisin B1 and Fumonisin-biotin conjugate. Also Fumonisin B2 was bound by the scFv. Modeling of both scFv and Fumonisin B1 molecule revealed a good fitting of structures. The antibody obtained can potentially be used for developing a rapid and affordable immunoassay for detection of food contamination and can be applied in immunoaffinity chromatography, usually carried out prior to HPLC analysis of mycotoxin-contaminated food and feed.
Jesper Molgaard Mogensen - One of the best experts on this subject based on the ideXlab platform.
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Occurrence of Fumonisins B2and B4in Retail Raisins
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Peter Boldsen Knudsen, Thomas Ostenfeld Larsen, Jesper Molgaard Mogensen, Kristian Fog NielsenAbstract:Concerns that raisins may be contaminated by Fumonisins stem from the persistent occurrence of Aspergillus niger spores on raisins and the recent discovery of Fumonisin production by A. niger on grapes, which leads to the widespread occurrence of Fumonisin B2 in wine. This study presents an LC-MS/MS survey of Fumonisins in retail raisins. In 10 of 21 brands collected in Denmark, Germany, and The Netherlands, Fumonisins B2 and B4 were detected at levels up to 13 and 1.3 μg/kg, respectively. Only Fumonisin B2 has been detected in wine, so the presence of Fumonisin B4 in raisins suggests that the Fumonisins are produced mainly during the drying process concomitant with the decreasing water activity. Analysis of multiple packages from one manufacturer showed a 3-fold package-to-package variation, suggesting that a few raisins per package are contaminated.
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widespread occurrence of the mycotoxin Fumonisin B2 in wine
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Jesper Molgaard Mogensen, Thomas Ostenfeld Larsen, Kristian Fog NielsenAbstract:Fumonisins are important mycotoxins because they are suspected to cause human and animal toxicoses by the consumption of contaminated corn-based food and feeds. However, with the discovery of Fumonisin production in grapes by Aspergillus niger, wine may also be a Fumonisin-containing commodity. In the present study, we have developed a simple and quantitative cation-exchange-based purification method for the subsequent isotope dilution liquid chromatography−tandem mass spectrometry (LC−MS/MS) determination of Fumonisins in wine. A comparative study of seven different solid-phase extraction (SPE) columns showed that polymeric mixed-mode reversed-phase (RP) cation-exchange columns were superior to classic silica-based cation and mixed-mode cation-exchange columns. A total of 77 wine samples from 13 countries were subsequently tested, and surprisingly, 18 (23%) were found to contain Fumonisin B2 in the range of 1−25 μg/L. These findings were further confirmed by immunoaffinity purification and re-analysis of...
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production of Fumonisin B2 and b4 by aspergillus niger on grapes and raisins
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Jesper Molgaard Mogensen, Jens Christian Frisvad, Ulf Thrane, Kristian Fog NielsenAbstract:The recent discovery of Fumonisin production in Aspergillus niger, raises concerns about the presence of these mycotoxins in grapes and raisins as well as other commodities where A. niger is a frequent contaminant. Here we investigate the potential production of Fumonisins in A. niger cultured on grapes and raisins. Sixty-six A. niger, 4 A. tubingensis, and 16 A. acidus strains isolated from raisins were tested for Fumonisin production on laboratory media. Neither A. tubingensis nor A. acidus strains produced Fumonisins, but 77% of A. niger strains did. None of the strains produced ochratoxin A. Ten selected Fumonisin producing A. niger strains were further able to produce Fumonisin B2 and Fumonisin B4 on grapes in the range 171−7841 μg Fumonisin B2/kg and 14−1157 μg Fumonisin B4/kg. Four selected strains were able to produce Fumonisin B2 (5−6476 μg/kg) and Fumonisin B4 (12−672 μg/kg) on raisins.
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Effect of temperature and water activity on the production of Fumonisins by Aspergillus niger and different Fusarium species.
BMC Microbiology, 2009Co-Authors: Jesper Molgaard Mogensen, Jens Christian Frisvad, Robert A Samson, Kristian Fog Nielsen, Ulf ThraneAbstract:Background Fumonisins are economically important mycotoxins which until recently were considered to originate from only a few Fusarium species. However recently a putative Fumonisin gene cluster was discovered in two different Aspergillus niger strains followed by detection of an actual Fumonisin B2 (FB2) production in four strains of this biotechnologically important workhorse.
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aspergillus acidus from puerh tea and black tea does not produce ochratoxin a and Fumonisin B2
International Journal of Food Microbiology, 2009Co-Authors: Jesper Molgaard Mogensen, Ulf Thrane, Janos Varga, Jens Christian FrisvadAbstract:Abstract Puerh tea is a unique Chinese fermented tea. Unlike other teas it is stored for a long period of time. Aspergillus niger is claimed to be the dominant microorganism in the Puerh tea manufacturing process and also to be common on tea in general. A. niger sensu stricto is known to produce the mycotoxins ochratoxin A, Fumonisins B2 and B4. With this in mind, we performed a preliminary study to determine if production of these mycotoxins by black Aspergilli isolated from Puerh and black tea can occur. An examination of 47 isolates from Puerh tea and black tea showed that none of these was A. niger. A part of the calmodulin gene in 17 isolates were sequenced, and these 17 isolates were all identified as Aspergillus acidus (= A. foetidus var. acidus). The rest of the 47 isolates were also identified as A. acidus from their metabolite profile. Neither production of ochratoxin A nor Fumonisins B2 and B4 by any of the 47 isolates were observed.
Björn Lauer - One of the best experts on this subject based on the ideXlab platform.
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Production of a single-chain variable fragment antibody against Fumonisin B1.
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Björn Lauer, Ilka Ottleben, Hans Jörg Jacobsen, Thomas ReinardAbstract:The selection of synthetic antibody fragments from large phage libraries has become a common method for the generation of specific antibodies. The technique is particularly valuable when antibodies against small, non-immunogenic molecules (haptens) or highly toxic substances have to be produced. In addition, haptens are usually coupled to protein carriers, bearing the risk that the free hapten is not detectable. Here, a single variable chain antibody (scFv) against the highly toxic mycotoxin Fumonisin B1 has been produced. The hapten was coupled via a linker to biotin. Using this conjugate and a naive scFv library, it was possible to circumvent both the necessity of immunization and the risk of a disguised hapten. The scFv obtained after three panning rounds was found to bind specifically to both free Fumonisin B1 and Fumonisin−biotin conjugate. Also Fumonisin B2 was bound by the scFv. Modeling of both scFv and Fumonisin B1 molecule revealed a good fitting of structures. The antibody obtained can potentia...
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Production of a single-chain variable fragment antibody against Fumonisin B1
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Björn Lauer, Ilka Ottleben, Hans Jörg Jacobsen, Thomas ReinardAbstract:The selection of synthetic antibody fragments from large phage libraries has become a common method for the generation of specific antibodies. The technique is particularly valuable when antibodies against small, non-immunogenic molecules (haptens) or highly toxic substances have to be produced. In addition, haptens are usually coupled to protein carriers, bearing the risk that the free hapten is not detectable. Here, a single variable chain antibody (scFv) against the highly toxic mycotoxin Fumonisin B1 has been produced. The hapten was coupled via a linker to biotin. Using this conjugate and a naive scFv library, it was possible to circumvent both the necessity of immunization and the risk of a disguised hapten. The scFv obtained after three panning rounds was found to bind specifically to both free Fumonisin B1 and Fumonisin-biotin conjugate. Also Fumonisin B2 was bound by the scFv. Modeling of both scFv and Fumonisin B1 molecule revealed a good fitting of structures. The antibody obtained can potentially be used for developing a rapid and affordable immunoassay for detection of food contamination and can be applied in immunoaffinity chromatography, usually carried out prior to HPLC analysis of mycotoxin-contaminated food and feed.
Janos Varga - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of black aspergillus species from onion and their potential for ochratoxin a and Fumonisin B2 production
Foodborne Pathogens and Disease, 2015Co-Authors: Youssuf A Gherbawy, Hesham Elhariry, Sandor Kocsube, Abdulaziz Bahobial, Bahig El Deeb, Abdulla Altalhi, Janos VargaAbstract:Abstract Onion bulbs can become contaminated with various molds during the storage period, the most important causal agents being black aspergilli (Aspergillus section Nigri). Taxonomic studies have revealed that this group of Aspergillus contains many species that cannot be reliably identified using standard morphological methods. Therefore, it is necessary to define the fungus causing this problem in the onion exactly, especially since some species assigned to section Nigri are well known as ochratoxin and/or Fumonisin producers. Sixty fungal isolates belonging to 10 fungal genera were isolated from 40 onion samples originated from the Taif region in Saudi Arabia. Black aspergilli were detected in 37 onion samples. Using primer pairs (awaspec and Cmd6) designed based on partial calmodulin gene sequence data, 37 isolates were identified as A. welwitschiae. The ochratoxin A and Fumonisin B2 contents of the onion samples were examined. No ochratoxins were detected in the collected samples, while Fumonisin ...
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aspergillus acidus from puerh tea and black tea does not produce ochratoxin a and Fumonisin B2
International Journal of Food Microbiology, 2009Co-Authors: Jesper Molgaard Mogensen, Ulf Thrane, Janos Varga, Jens Christian FrisvadAbstract:Abstract Puerh tea is a unique Chinese fermented tea. Unlike other teas it is stored for a long period of time. Aspergillus niger is claimed to be the dominant microorganism in the Puerh tea manufacturing process and also to be common on tea in general. A. niger sensu stricto is known to produce the mycotoxins ochratoxin A, Fumonisins B2 and B4. With this in mind, we performed a preliminary study to determine if production of these mycotoxins by black Aspergilli isolated from Puerh and black tea can occur. An examination of 47 isolates from Puerh tea and black tea showed that none of these was A. niger. A part of the calmodulin gene in 17 isolates were sequenced, and these 17 isolates were all identified as Aspergillus acidus (= A. foetidus var. acidus). The rest of the 47 isolates were also identified as A. acidus from their metabolite profile. Neither production of ochratoxin A nor Fumonisins B2 and B4 by any of the 47 isolates were observed.
