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Marti Obrie - One of the best experts on this subject based on the ideXlab platform.
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fungal contamination of big bale grass silage on irish farms predominant mould and yeast species and features of bales and silage
Grass and Forage Science, 2008Co-Authors: P D Forristal, Padraig Okiely, Marti Obrie, Hube T FulleAbstract:The extent of visible fungal growth and the identity of the predominant fungi causing spoilage of baled grass silage were recorded on 180 farms in Ireland. Fungal growth was evident on bales on 174 of the 180 farms visited and on 331 of the 360 bales examined. The mean proportion of surface area of bale, that was affected, was 0·06. Silage-making method, storage characteristics and geographical location were significantly associated with the level of fungal contamination on bales. Fungal contamination was higher (P < 0·001) in bales where the surrounding polythene stretch-film was visibly damaged compared with bales where the film appeared intact. A strong positive relationship was found between polythene film damage and dry-matter content of the silage. The predominant fungus affecting the largest numbers of bales was Penicillium roqueforti. Other fungi frequently isolated included Schizophyllum commune, Pichia fermentans and Penicillium paneum. The distribution of individual fungi on bales was associated with geographical location, weather at harvest, and lactic and butyric acid concentrations of the silage. Penicillium roqueforti and P. paneum were more common on bales harvested in dry weather and with higher concentrations of butyric and propionic acids in the silage. Overall, a high incidence of visible fungal growth was recorded on bales throughout the country and the extent of colonization and fungal species occurring were not random.
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mycotoxins and other secondary metabolites produced in vitro by Penicillium paneum frisvad and Penicillium roqueforti thom isolated from baled grass silage in ireland
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Marti Obrie, P D Forristal, Hube T Fulle, Kristian Fog Nielse, Padraig Okiely, Jens Christia FrisvadAbstract:Secondary metabolites produced by Penicillium paneum and Penicillium roqueforti from baled grass silage were analyzed. A total of 157 isolates were investigated, comprising 78 P. paneum and 79 P. roqueforti isolates randomly selected from more than 900 colonies cultured from bales. The findings mostly agreed with the literature, although some metabolites were not consistently produced by either fungus. roquefortine C, marcfortine A, and andrastin A were consistently produced, whereas PR toxin and patulin were not. Five silage samples were screened for fungal metabolites, with two visually moldy samples containing up to 20 mg/kg of roquefortine C, mycophenolic acid, and andrastin A along with minor quantities (0.1-5 mg/kg) of roquefortines A, B, and D, festuclavine, marcfortine A, and agroclavine. Three visually nonmoldy samples contained low amounts of mycophenolic acid and andrastin A. The ability of both molds to produce a diverse range of secondary metabolites in vitro and in silage should be a concern to livestock producers.
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fungi isolated from contaminated baled grass silage on farms in the irish midlands
Fems Microbiology Letters, 2005Co-Authors: P D Forristal, Padraig Okiely, Marti Obrie, Hube T FulleAbstract:The incidence of fungal growth on baled grass silage was recorded on 35 farms in the Irish Midlands in 2003. Fungal colonies were visible on 58 of 64 bales examined and the number of colonies per bale ranged from 1 to 12. On average, 5% of bale surface areas were affected. The fungus most prevalent on bales was Penicillium roqueforti, present on 86% of bales and representing 52% of all isolates. Other moulds isolated were Penicillium paneum, Geotrichum, Fusarium and mucoraceous species. Schizophyllum commune was observed protruding through the plastic film on bales on 17 of the 35 farms.
Hube T Fulle - One of the best experts on this subject based on the ideXlab platform.
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fungal contamination of big bale grass silage on irish farms predominant mould and yeast species and features of bales and silage
Grass and Forage Science, 2008Co-Authors: P D Forristal, Padraig Okiely, Marti Obrie, Hube T FulleAbstract:The extent of visible fungal growth and the identity of the predominant fungi causing spoilage of baled grass silage were recorded on 180 farms in Ireland. Fungal growth was evident on bales on 174 of the 180 farms visited and on 331 of the 360 bales examined. The mean proportion of surface area of bale, that was affected, was 0·06. Silage-making method, storage characteristics and geographical location were significantly associated with the level of fungal contamination on bales. Fungal contamination was higher (P < 0·001) in bales where the surrounding polythene stretch-film was visibly damaged compared with bales where the film appeared intact. A strong positive relationship was found between polythene film damage and dry-matter content of the silage. The predominant fungus affecting the largest numbers of bales was Penicillium roqueforti. Other fungi frequently isolated included Schizophyllum commune, Pichia fermentans and Penicillium paneum. The distribution of individual fungi on bales was associated with geographical location, weather at harvest, and lactic and butyric acid concentrations of the silage. Penicillium roqueforti and P. paneum were more common on bales harvested in dry weather and with higher concentrations of butyric and propionic acids in the silage. Overall, a high incidence of visible fungal growth was recorded on bales throughout the country and the extent of colonization and fungal species occurring were not random.
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mycotoxins and other secondary metabolites produced in vitro by Penicillium paneum frisvad and Penicillium roqueforti thom isolated from baled grass silage in ireland
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Marti Obrie, P D Forristal, Hube T Fulle, Kristian Fog Nielse, Padraig Okiely, Jens Christia FrisvadAbstract:Secondary metabolites produced by Penicillium paneum and Penicillium roqueforti from baled grass silage were analyzed. A total of 157 isolates were investigated, comprising 78 P. paneum and 79 P. roqueforti isolates randomly selected from more than 900 colonies cultured from bales. The findings mostly agreed with the literature, although some metabolites were not consistently produced by either fungus. roquefortine C, marcfortine A, and andrastin A were consistently produced, whereas PR toxin and patulin were not. Five silage samples were screened for fungal metabolites, with two visually moldy samples containing up to 20 mg/kg of roquefortine C, mycophenolic acid, and andrastin A along with minor quantities (0.1-5 mg/kg) of roquefortines A, B, and D, festuclavine, marcfortine A, and agroclavine. Three visually nonmoldy samples contained low amounts of mycophenolic acid and andrastin A. The ability of both molds to produce a diverse range of secondary metabolites in vitro and in silage should be a concern to livestock producers.
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fungi isolated from contaminated baled grass silage on farms in the irish midlands
Fems Microbiology Letters, 2005Co-Authors: P D Forristal, Padraig Okiely, Marti Obrie, Hube T FulleAbstract:The incidence of fungal growth on baled grass silage was recorded on 35 farms in the Irish Midlands in 2003. Fungal colonies were visible on 58 of 64 bales examined and the number of colonies per bale ranged from 1 to 12. On average, 5% of bale surface areas were affected. The fungus most prevalent on bales was Penicillium roqueforti, present on 86% of bales and representing 52% of all isolates. Other moulds isolated were Penicillium paneum, Geotrichum, Fusarium and mucoraceous species. Schizophyllum commune was observed protruding through the plastic film on bales on 17 of the 35 farms.
Johan Schnurer - One of the best experts on this subject based on the ideXlab platform.
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nutrient effects on biocontrol of Penicillium roqueforti by pichia anomala j121 during airtight storage of wheat
Applied and Environmental Microbiology, 2005Co-Authors: Ulrika Adel Druvefors, Volkmar Passoth, Johan SchnurerAbstract:The biocontrol yeast Pichia anomala inhibits the growth of a variety of mold species. We examined the mechanism underlying the inhibition of the grain spoilage mold Penicillium roqueforti by the biocontrol yeast P. anomala J121 during airtight storage. The biocontrol effect in a model grain silo with moist wheat (water activity of 0.96) was enhanced when complex medium, maltose, or glucose was added. Supplementation with additional nitrogen or vitamin sources did not affect the biocontrol activity of the yeast. The addition of complex medium or glucose did not significantly influence the yeast cell numbers in the silos, whether in the presence or absence of P. roqueforti. Mold growth was not influenced by the addition of nutrients, if cultivated without yeast. The products of glucose metabolism, mainly ethanol and ethyl acetate, increased after glucose addition to P. anomala-inoculated treatments. Our results suggest that neither competition for nutrients nor production of a glucose-repressible cell wall lytic enzyme is the main mode of action of biocontrol by P. anomala in this grain system. Instead, the mold-inhibiting effect probably is due to the antifungal action of metabolites, most likely a combination of ethyl acetate and ethanol, derived from glycolysis. The discovery that sugar amendments enhance the biocontrol effect of P. anomala suggests novel ways of formulating biocontrol yeasts.
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Pichia anomala as a biocontrol agent during storage of high-moisture feed grain under airtight conditions
Postharvest Biology and Technology, 1999Co-Authors: Stina Petersson, Nils Jonsson, Johan SchnurerAbstract:Abstract Pichia anomala is antagonistic against a range of spoilage molds in vitro as well as against Penicillium roqueforti in high-moisture wheat during malfunctioning airtight storage in laboratory experiments. The use of Pichia anomala to improve the postharvest control of Penicillium roqueforti during airtight storage of feed grain was evaluated in outdoor silos. Inoculated and control winter wheat (cultivar Kosack) in 160-kg portions were stored at a water activity of 0.93 for 12 months in silos that were opened twice a week. During the first 2 months, inoculated Pichia anomala increased to about 107 colony-forming units (CFU)/g, while naturally occurring Pichia anomala in the treatments without inoculated yeast increased from 104 to 106 CFU/g. During the same period, CO2 concentrations increased to almost 70% and stabilized at 50–60%. During the coldest period, O2 concentrations of
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biocontrol of mold growth in high moisture wheat stored under airtight conditions by pichia anomala pichia guilliermondii and saccharomyces cerevisiae
Applied and Environmental Microbiology, 1995Co-Authors: Stina Petersson, Johan SchnurerAbstract:Pichia anomala inhibits the growth of Penicillium roqueforti and Aspergillus candidus on agar. In this investigation, antagonistic activity on agar against 17 mold species was determined. The abilities of Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae to inhibit the growth of the mold Penicillium roqueforti in nonsterile high-moisture wheat were compared by adding 10(3) Penicillium roqueforti spores and different amounts of yeast cells per gram of wheat. Inoculated grain was packed in glass tubes, incubated at 25 degrees C with a restricted air supply, and the numbers of yeast and mold CFU were determined on selective media after 7 and 14 days. Pichia anomala reduced growth on agar plates for all of the mold species tested in a dose-dependent manner. Aspergillus fumigatus and Eurotium amstelodami were the most sensitive, while Penicillium italicum and Penicillium digitatum were the most resistant. Pichia anomala had the strongest antagonistic activity in wheat, with 10(5) and 10(6) CFU/g completely inhibiting the growth of Penicillium roqueforti. Inhibition was least pronounced at the optimum temperature (21 degrees C) and water activity (0.95) for the growth of Penicillium roqueforti. Pichia guilliermondii slightly reduced the growth of Penicillium roqueforti in wheat inoculated with 10(5) and 10(6) yeast CFU/g. S. cerevisiae inhibited mold growth only weakly at the highest inoculum level. Pichia anomala grew from 10(3) to 10(7) CFU/g of wheat in 1 week. To reach the same level, Pichia guilliermondii had to be inoculated at 10(4) CFU while S. cerevisiae required an inoculum of 10(5) CFU to reach 10(7) CFU/g of wheat.
Tatiana Giraud - One of the best experts on this subject based on the ideXlab platform.
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Blue cheese-making has shaped the population genetic structure of the mould Penicillium roqueforti.
PLOS ONE, 2017Co-Authors: Jeanne Ropars, Sandrine Lacoste, Manuela López-villavicencio, Alodie Snirc, Tatiana GiraudAbstract:Background: Penicillium roqueforti is a filamentous fungus used for making blue cheeses worldwide. It also occurs as a food spoiler and in silage and wood. Previous studies have revealed a strong population genetic structure, with specific traits associated with the different populations. Here, we used a large strain collection from worldwide cheeses published recently to investigate the genetic structure of P. roqueforti. Principal findings: We found a genetic population structure in P. roqueforti that was consistent with previous studies, with two main genetic clusters (W+C+ and W-C-, i.e., with and without horizontal gene transferred regions CheesyTer and Wallaby). In addition, we detected a finer genetic subdivision that corresponded to the environment and to protected designation of origin (PDO), namely the Roquefort PDO. We indeed found evidence for eight genetic clusters, one of the cluster including only strains from other environments than cheeses, and another cluster encompassing only strains from the Roquefort PDO. The W-C- and W+C+ cheese clusters were not the most closely related ones, suggesting that there may have been two independent domestication events of P. roqueforti for making blue cheeses. Significance:The additional population structure revealed here may be relevant for cheese-makers and for understanding the history of domestication in P. roqueforti.
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Population structure of Penicillium roqueforti.
2017Co-Authors: Jeanne Ropars, Sandrine Lacoste, Manuela López-villavicencio, Alodie Snirc, Tatiana GiraudAbstract:Coefficients of membership in various gene pools inferred with the STRUCTURE program of our 240 Penicillium roqueforti strains, based on the eight polymorphic microsatellite markers. STRUCTURE was run from K = 1 to K = 10 (showed up to K = 8 as no additional well-delimited cluster was revealed above). For K = 7 and K = 8 only the main mode are shown, where simulations could find the required number of clusters. The legend below the barplots indicates whether strains carry the Wally and CheesyTer genomic islands in their genomes (W+C+) or not (W-C-) and whether they have been collected from cheeses, belonging or not to the Roquefort protected designation of origin (PDO), or from other environments, such as silage or spoiled food.
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RESEARCH ARTICLE Insights into Penicillium roqueforti Morphological and Genetic Diversity
2016Co-Authors: Guillaume Gillot, Manuela López-villavicencio, Stella Debaets, Antoine Branca, Joëlle Dupont, Jean-luc Jany, Monika Coton, Jeanne Ropars, Gaétan Le Floch, Tatiana GiraudAbstract:Fungi exhibit substantial morphological and genetic diversity, often associated with cryptic species differing in ecological niches. Penicillium roqueforti is used as a starter culture for blue-veined cheeses, being responsible for their flavor and color, but is also a common spoilage organism in various foods. Different types of blue-veined cheeses are manufac-tured and consumed worldwide, displaying specific organoleptic properties. These features may be due to the different manufacturing methods and/or to the specific P. roqueforti strains used. Substantial morphological diversity exists within P. roqueforti and, although not taxonomically valid, several technological names have been used for strains on different cheeses (e.g., P. gorgonzolae, P. stilton). A worldwide P. roqueforti collection from 120 indi-vidual blue-veined cheeses and 21 other substrates was analyzed here to determine (i) whether P. roqueforti is a complex of cryptic species, by applying the Genealogical Concor-dance Phylogenetic Species Recognition criterion (GC-PSR), (ii) whether the population structure assessed using microsatellite markers correspond to blue cheese types, and (iii) whether the genetic clusters display different morphologies. GC-PSR multi-locus sequenc
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Sex in Cheese: Evidence for Sexuality in the Fungus Penicillium roqueforti
2016Co-Authors: Jeanne Ropars, Monika Coton, Eric Fontanillas, Fabienne Malagnac, Tatiana GiraudAbstract:Although most eukaryotes reproduce sexually at some moment of their life cycle, as much as a fifth of fungal species were thought to reproduce exclusively asexually. Nevertheless, recent studies have revealed the occurrence of sex in some of these supposedly asexual species. For industrially relevant fungi, for which inoculums are produced by clonal-subcultures since decades, the potentiality for sex is of great interest for strain improvement strategies. Here, we investigated the sexual capability of the fungus Penicillium roqueforti, used as starter for blue cheese production. We present indirect evidence suggesting that recombination could be occurring in this species. The screening of a large sample of strains isolated from diverse substrates throughout the world revealed the existence of individuals of both mating types, even in the very same cheese. The MAT genes, involved in fungal sexual compatibility, appeared to evolve under purifying selection, suggesting that they are still functional. The examination of the recently sequenced genome of the FM 164 cheese strain enabled the identification of the most important genes known to be involved in meiosis, which were found to be highly conserved. Linkage disequilibria were not significant among three of the six marker pairs and 11 out of the 16 possible allelic combinations were found in the dataset. Finally, the detection of signatures of repeat induced point mutations (RIP) in repeated sequences and transposable elements reinforces the conclusion that P. roqueforti underwent more or less recen
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Genotypes Proq
2016Co-Authors: Jeanne Ropars, Manuela López-villavicencio, Alodie Snirc, Guillaume Gillot, Joëlle Dupont, Jean-luc Jany, Monika Coton, Emmanuel Coton, Tatiana GiraudAbstract:Microsatellite alleles for Penicillium roqueforti strain
Juanfrancisco Martin - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of the pr toxin gene cluster in Penicillium roqueforti and Penicillium chrysogenum cross talk of secondary metabolite pathways
Fungal Genetics and Biology, 2014Co-Authors: Pedro I Hidalgo, Ricardo V Ullan, Silvia M Albillos, Olimpio Montero, Maria Angeles Fernandezbodega, Carlos Garciaestrada, Marta Fernandezaguado, Juanfrancisco MartinAbstract:Abstract The PR-toxin is a potent mycotoxin produced by Penicillium roqueforti in moulded grains and grass silages and may contaminate blue-veined cheese. The PR-toxin derives from the 15 carbon atoms sesquiterpene aristolochene formed by the aristolochene synthase (encoded by ari 1). We have cloned and sequenced a four gene cluster that includes the ari 1 gene from P. roqueforti . Gene silencing of each of the four genes (named prx 1 to prx 4) resulted in a reduction of 65–75% in the production of PR-toxin indicating that the four genes encode enzymes involved in PR-toxin biosynthesis. Interestingly the four silenced mutants overproduce large amounts of mycophenolic acid, an antitumor compound formed by an unrelated pathway suggesting a cross-talk of PR-toxin and mycophenolic acid production. An eleven gene cluster that includes the above mentioned four prx genes and a 14-TMS drug/H + antiporter was found in the genome of Penicillium chrysogenum . This eleven gene cluster has been reported to be very poorly expressed in a transcriptomic study of P. chrysogenum genes under conditions of penicillin production (strongly aerated cultures). We found that this apparently silent gene cluster is able to produce PR-toxin in P. chrysogenum under static culture conditions on hydrated rice medium. Noteworthily, the production of PR-toxin was 2.6-fold higher in P. chrysogenum npe10 , a strain deleted in the 56.8 kb amplifiable region containing the pen gene cluster, than in the parental strain Wisconsin 54-1255 providing another example of cross-talk between secondary metabolite pathways in this fungus. A detailed PR-toxin biosynthesis pathway is proposed based on all available evidence.