title: Streptomyces strains producing mitochondriotoxic antimycin A found in cereal grains.
abstract: Reasons for mammalian cell toxicity observed in barley and spring wheat grains were sought. Streptomyces sp. isolates from wheat and barley produced heat-stable methanol-soluble substances which inhibited the motility of exposed porcine spermatozoa used as a toxicity indicator. Several barley isolates produced antimycin A (2 to 5 ng/mg wet wt of biomass), a macrolide antibiotic known to block oxygen utilization in mitochondria. The antimycin-producing isolates were members of the Streptomyces albidoflavus group. In in vitro assays with porcine kidney tubular epithelial cells, the specific toxicity of antimycin A towards mitochondria was higher than that of the mycotoxin enniatin B but lower than that of the mitochondriotoxins cereulide and paenilide, produced by food-related Bacillus cereus and Paenibacillus tundrae, respectively. The toxic wheat isolates, related to Streptomyces sedi, did not produce antimycin A and or any other known toxin. Our results suggest that the presence of toxin-producing streptomycetes in stored cereal grains may pose a thus far unrecognized threat for food and feed safety.
authors.affiliation: Department of Food and Environmental Sciences (Microbiology), Biocenter 1, POB 56, 00014 Helsinki University, Finland. Electronic address: stiina.rasimus@helsinki.fi.
authors.forename: Stiina
authors.initials: S
authors.lastname: Rasimus-Sahari
authors.affiliation: Department of Food and Environmental Sciences (Microbiology), Biocenter 1, POB 56, 00014 Helsinki University, Finland.
authors.forename: Raimo
authors.initials: R
authors.lastname: Mikkola
authors.affiliation: Department of Food and Environmental Sciences (Microbiology), Biocenter 1, POB 56, 00014 Helsinki University, Finland.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Andersson
authors.affiliation: Product Safety Unit, Finnish Food Safety Authority (Evira), Mustialankatu 3, 00790 Helsinki, Finland.
authors.forename: Marika
authors.initials: M
authors.lastname: Jestoi
authors.affiliation: Department of Food and Environmental Sciences (Microbiology), Biocenter 1, POB 56, 00014 Helsinki University, Finland.
authors.forename: Mirja
authors.initials: M
authors.lastname: Salkinoja-Salonen
mesh_terms: D000818:Animals; D000968:Antimycin A / Q000096:biosynthesis*; D002460:Cell Line; D002523:Edible Grain / Q000382:microbiology*; D005516:Food Microbiology; D059022:Food Safety; D001467:Hordeum / Q000382:microbiology*; D008297:Male; D008928:Mitochondria / Q000473:pathology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D021241:Spectrometry, Mass, Electrospray Ionization; D013302:Streptomyces / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D013552:Swine; D014908:Triticum / Q000382:microbiology*
chemical_list: D012336:RNA, Ribosomal, 16S; D000968:Antimycin A
keywords: Antimycin A; Antimycin A (PubChem CID: 12550); Cereal grains; Enniatin B; Enniatin B (PubChem CID: 164754); Food safety; Mitochondriotoxic; Streptomyces albidoflavus