engleski

Post-flood indoor occurrence of toxigenic Aspergilli from the Versicolores clade: is it dangerous?

Two years after the flood in Gunja (eastern Croatia) majority of the houses have been repaired but fungal indoor colonisation is still present and may represent health risk. In winter and summer of 2016 and 2017 samples of airborne and dustborne fungi along with dust were collected in repaired houses of Gunja in order to explore seasonal variations of Aspergilli indoor levels, Aspergilli mycotoxin-producing capacity and mycotoxins in dust, in contrast to control village Gornji Stupnik. Aspergilli (Versicolores) were among dominant Aspergilli at both locations and majority of isolates produced sterigmatocystin (STC) and 5-methoxy-STC and (2). Here we present ; 1) species diversity (calmodulin sequence-based methods) ; 2) presence of STC and 5-methoxy-STC in the dust (multitoxin HPLC/MS/MS method) ; 3) cytotoxicity (MTT test), genotoxicity (alkaline comet test) and immunomodulatory effects (ELISA) of STC vs STC- producing Aspergilli using human lung A549 cells and THP-1 cells macrophage-like cells. A. jensenii, A. creber, A. puulaauensis, A. griseoaurantiacus and A. sydowi were determined so far (ongoing project). A. jensenii was chosen for preliminary experiments on cells. Highest concentration of STC (0.59 ug/g) and 5-metoxy-STC (7.70 ug/g) in dust were detected in winter (2017) in Gunja. THP-1 cells (IC50 = 0.6 ug/ml) were twice as sensitive to STC than A549 cells (IC50 = 1.3 ug/ml) ; dose-response for A. jensenii extract in both cell lines was similar (IC50>3.2 ug/ml). Subcytotoxic concentrations of STC (0.032 and 0.32 ug/ml) and A. jensenii containing the same concentrations of STC showed different immunomodulatory pattern in THP-1 cells ; STC induced significant concentration-dependent increase of IL-1b, IL-6 and IL-8 and decrease of TNF-α, while A. jensenii did not significantly affect cytokine levels compared to control (0.1% DMSO). Alkaline comet assay showed that STC alone evoked concentration-dependent increase of DNA damage (tail intensity) in A549 cells ; both concentrations of A. jensenii also significantly increased tail intensity in comparison to control but lower concentration provoked greater DNA damage. Differences in toxicity pattern of single STC and A. jensenii may be explained by the presence of 5-metoxy-STC and possibly other metabolites which might have antagonised STC toxicity.

Aspergillus jensenii, sterigmatocystin, airborne fungi, cytotoxicity, genotoxicity

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