pr-toxin and roquefortine

Ripening of blue-veined cheeses, such as the French Bleu and Roquefort, the Italian Gorgonzola, the English Stilton, the Danish Danablu or the Spanish Cabrales, Picón Bejes-Tresviso, and Valdeón, requires the growth and enzymatic activity of the mold Penicillium roqueforti, which is responsible for the characteristic texture, blue-green spots, and aroma of these types of cheeses. This filamentous fungus is able to synthesize different secondary metabolites, including andrastins, mycophenolic acid, and several mycotoxins, such as roquefortines C and D, PR-toxin and eremofortins, isofumigaclavines A and B, and festuclavine. This review provides a detailed description of the main secondary metabolites produced by P. roqueforti in blue cheese, giving a special emphasis to roquefortine, PR-toxin and mycophenolic acid, and their biosynthetic gene clusters and pathways. The knowledge of these clusters and secondary metabolism pathways, together with the ability of P. roqueforti to produce beneficial secondary metabolites, is of interest for commercial purposes.

Topics: Biological Products; Biosynthetic Pathways; Cheese; Heterocyclic Compounds, 4 or More Rings; Indoles; Multigene Family; Mycophenolic Acid; Naphthols; Penicillium; Piperazines; Secondary Metabolism

Isolated and identified toxigenic and nontoxigenic Penicillium roqueforti (PR) strains from moldy tulum cheeses were inoculated into tulum cheeses made in the laboratory and ripened at 5 and 12 degrees C. Mycotoxin (patulin, penicillic acid, PR toxin, and roquefortine) formation in the control and mold-inoculated cheeses were detected by thin-layer chromatography on the first through fourth months of ripening. Patulin, penicillic acid, and PR toxin were not detected in the experimental cheeses. Only roquefortine was detected in cheese inoculated with the toxigenic strain of the mold and ripened at 5 and 12 degrees C on the third and first months of ripening, respectively. Toxin in cheeses ripened at 5 and 12 degrees C was 2.1 to 2.4 and 2.1 to 3.8 mg/kg cheese, respectively.

Topics: Cheese; Chromatography, Thin Layer; Colony Count, Microbial; Food Microbiology; Heterocyclic Compounds, 4 or More Rings; Indoles; Mycotoxins; Naphthols; Patulin; Penicillic Acid; Penicillium; Piperazines; Species Specificity; Temperature; Time Factors

Several strains of Penicillium are used for the production of mold-ripened cheeses, and some of them are able to produce mycotoxins. The aims of the research were the determination of roquefortine C and PR toxin in domestic and imported blue cheeses, the identification of the penicillia used as starter, and the investigation of their capacity for producing toxins in culture media. Roquefortine C was always found in the cheeses at levels ranging from 0.05 to 1.47 mg/kg, whereas the PR toxin was never found. The identification of the fungal strains present in the domestic cheeses included Penicillium glabrum, Penicillium roqueforti, and Penicillium cyclopium in the Gorgonzola "dolce" and Penicillium roqueforti in the Gorgonzola "naturale"; in one case, the presence of Penicillium crustosum was observed. The strains isolated from the foreign cheeses belonged to P. roqueforti. The strains were able to produce between 0.18 and 8.44 mg/liter of roquefortine in yeast extract sucrose medium and between 0.06 and 3.08 mg/liter and less than 0.05 mg/liter when inoculated in milk at 20 degrees C for 14 days and 4 degrees C for 24 days, respectively. Linear relations between production of roquefortine in culture media and cheeses did not emerge. PR toxin ranged from less than 0.05 to 60.30 mg/liter in yeast extract sucrose medium and was produced in milk at 20 degrees C from only one strain. The low levels and the relatively low toxicity of roquefortine make the consumption of blue cheese safe for the consumer.

Topics: Cheese; Chromatography, High Pressure Liquid; Ergolines; Heterocyclic Compounds, 4 or More Rings; Indoles; Mycotoxins; Naphthols; Penicillium; Piperazines; Time Factors

Seventy-six strains of Penicillium roqueforti used as starter cultures for mould ripened blue cheeses have been analysed for their RAPD genotype by using three different primers. A comparison of the RAPD patterns within each primer group revealed that the genetic constitution of the strains was similar, as most of the strains showed very similar overall patterns. Despite these similarities with each primer, distinct RAPD genotype groups could be identified. With one of the primers, it was possible to detect two heteropolymorphic DNA regions resulting in 13 different groups. With the other two primers, three or four groups could be identified. Between the groups of the different primers marked correspondence with respect to strain distribution could be observed, indicating that the polymorphisms detected by the primers were not independent. The RAPD patterns were compared to the production of secondary metabolites. A correlation was observed between the RAPD patterns of all primers and the production of mycophenolic acid. In addition, one of the primer (ari1) was able to distinguish between P. roqueforti strains producing larger or smaller numbers of metabolites.

Topics: Cheese; DNA Primers; DNA, Fungal; Ergolines; Genes, Fungal; Genotype; Heterocyclic Compounds, 4 or More Rings; Indoles; Mycological Typing Techniques; Mycophenolic Acid; Mycotoxins; Naphthols; Penicillium; Piperazines; Random Amplified Polymorphic DNA Technique

Topics: Chromatography, Thin Layer; Densitometry; Ergolines; Heterocyclic Compounds, 4 or More Rings; Indoles; Mycotoxins; Naphthols; Penicillium; Piperazines; Spectrophotometry, Ultraviolet

Topics: Administration, Oral; Animals; Epoxy Compounds; Ergolines; Female; Heterocyclic Compounds, 4 or More Rings; Indoles; Injections, Intraperitoneal; Lethal Dose 50; Male; Mice; Mycotoxins; Naphthols; Penicillium; Piperazines