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Acrebol, a novel toxic peptaibol produced by an Acremonium exuviarum indoor isolate
Author(s) -
Andersson M.A.,
Mikkola R.,
Raulio M.,
Kredics L.,
Maijala P.,
SalkinojaSalonen M.S.
Publication year - 2009
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2008.04062.x
Subject(s) - toxin , biology , cycloheximide , mitochondrion , toxicity , fungus , microbiology and biotechnology , acremonium , motility , biochemistry , chemistry , botany , protein biosynthesis , genetics , organic chemistry
Abstract Aims: To identify a toxin and its producer isolated from woody material in a building where the occupants experienced serious ill health symptoms. Methods and Results: Hyphal extracts of an indoor fungus, identified as the cycloheximide‐tolerant species Acremonium exuviarum , inhibited motility of boar spermatozoa (EC 50 5 ± 2 μg of crude solids ml −1 ) and caused cytolysis of murine neuroblastoma cells (MNA) and feline fetal lung cells (FL). The responsible substances were purified and identified as two structurally similar, heat‐stable, novel, toxic peptaibols, 1726 Da and 1740 Da, respectively, with amino acid sequences of Acetyl‐Phe‐Iva/Val‐Gln‐Aib‐Ile‐Thr‐Leu‐Aib‐Pro‐Aib‐Gln‐Pro‐Aib‐(X‐X‐X)‐SerOH and Acetyl‐Phe‐Iva/Val‐Gln‐Aib‐Ile‐Thr‐Leu‐Val‐Pro‐Aib‐Gln‐Pro‐Aib‐(X‐X‐X)‐SerOH. Purified acrebol inhibited motility of boar sperm, depleted ATP half‐content in 1 day (EC 50 of 0·1 μg ml −1 , 60 nmol l −1 ) depolarised the mitochondria after 2 days, but did not affect the cellular content in NADH. This indicates mitochondrial toxicity. Plate‐grown biomass of A. exuviarum BMB4 contained 0·1–1% (w/w) of acrebol, depending on the culture medium. Conclusions: Acrebol paralysed the energy generation of mammalian cells suggesting that mitochondria were its target of action. Significance and Impact of the Study: Acremonium exuviarum, as an indoor fungus, is potentially hazardous to health because of the toxic peptaibols that it produces.