engleski

Biodiversity and toxic properties of aspergillus section versicolores - what do floods have to do with it?

Aspergilli section Versicolores, producers of mycotoxin sterigmatocystin (STC), dominated the fungi isolated from air and dust in flood-affected homes (Gunja) and control houses (Gornji Stupnik) in Croatia. As many as 70% of isolates were able to produce STC and some isolates also produced its derivate 5-methoxy-STC. How this could affect human health? Here we present: a) Aspergilli section Versicolores species diversity in air and dust (calmodulin sequence-based methods) ; b) occurrence of STC in contrast to other mycotoxins in dust (multitoxin HPLC/MS/MS) ; c) immunomodulatory effects (ELISA) and genotoxicity (alkaline comet assay) of STC vs STC-producing Aspergilli extracts in THP-1 cells macrophage-like cells and human lung A549 cells ; d) genotoxic effects of STC and 5-methoxy-STC in lungs of male Wistar rats upon intratracheal instillation in concentrations found in dust. Most of the Versicolores isolates were from Gunja (91/125). A. jensenii (31%) and A. creber (30%) were the most frequent, followed by A. puulaauensis (10 %), A. protuberus (9 %), A. tennesseensis (6 %), A. sydowii (5 %), A. amoenus (3 %), A. venenatus (2 %), A. fructus (1.6 %), A. griseoaurantiacus (1 %) and the recently described A. pepii (1 %). Among the 75 mycotoxins detected in dust, STC (70%) and 5-methoxy-STC (50%) were the most dominant. The highest concentrations of STC (0.59 mg/g) and 5-methoxy-STC (7.70 mg/g) in dust were detected in Gunja. Subcytotoxic concentrations of STC (0.032 and 0.32 µg/ml) induced a concentration-dependent increase of IL-1b, IL-6 and IL-8 and a decrease of TNF-α ; A. jensenii and A. creber extracts containing the same concentrations of STC did not significantly affect cytokine levels. STC evoked a concentration-dependent increase of DNA damage in A549 cells ; Aspergilli significantly increased DNA breaks, but a lower concentration provoked greater DNA damage. In rat lungs, levels of DNA damage were similar upon treatment with STC and 5-methoxy-STC, but STC was applied in a 10-fold lower dose. The results of combined treatment suggested possible antagonistic interactions. Taken together, differences in toxicity pattern of single STC and Aspergilli may be explained by the presence of 5-methoxy-STC and possibly other metabolites that antagonised STC toxicity.

Aspergillus section Versicolores, sterigmatocystin, 5-methoxysterigmatocystin

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