A mould Aspergillus versicolor clearly dominates in damp and mouldy indoor environments under Slovak dwelling/public building conditions (up to 1/3 of all isolates during the last decade's surveys). Nearly all of its isolates are able to synthesize a mycotoxin sterigmatocystin (detected by LC/MS-MS), that showed severe in vitro as well as in vivo toxic potential in animal experiments (after intratracheal instillation to rats). In vitro toxicity of complex chloroformextractable endo-and exometabolites of 10 indoor, and related outdoor, A. versicolor isolates from a heavily mouldy kids' fashion store in Slovakia with complaints from the occupants of irritation of their airways has been evaluated by a bioassay with tracheal organ cultures of one-day old chicks (20 microg of toxicants per mL of cultivation medium). In the in vivo experiments, respiratory toxicity of the same metabolite mixtures was tested in Wistar rats during three days. The inflammatory and cytotoxic biomarkers were then analyzed in bronchoalveolar lavage fluid. Searching for the fungus possible source, molecular epidemiological study of the isolates was performed using RAMP PCR. Strains colonizing the indoor walls of the shop were the highest correlated to the outdoor airborne ones (Pearson correlation 97%). While indoor airborne isolates correlated to the strains growing on retailed clothes at the levels of 90 or 86% according to Pearson. All micromycetes produced secondary metabolites that ceased ciliary beating in tracheal epithelium in the organ cultures already in 24 hrs of the activity, i.e. in the sense of the method used, they belong to strong toxicants. Two of the isolates tested also produced extrolites without toxic effects detectable by the method. The metabolites also showed certain cytotoxic Environmental Health and Biomedicine 135

The lung is a major target organ for insults induced by environmental pollutants. Following the effect of microfungal exposure relating to less studied topics, health complaints, particularly in mouldy houses, may be associated with microfungal exposure. The pulmonary health problems can be evoked both by inhalation of spores or their secondary metabolites. The fungal secondary metabolites represent a mixture of different active compounds and the mycotoxins may be a common part of them. Our study was focused on the effect of secondary metabolites produced by Aspergillus versicolor, a frequent indoor colonizer. The Wistar rats were intratracheally exposed to isolated metabolites produced by A. versicolor and after 3 days exposure the animals were sacrificed and the antioxidant status was estimated in lung tissue and bronchoalveolar lavage fluid (BALF). Alveolar macrophages and alveolar epithelial type II cellsfrom toxicological point of view the most important cells -were isolated and their antioxidant status and DNA damage were evaluated. The results did not show statistically significant changes of antioxidant status either in lungs or in the BALF, but the DNA damage was enhanced in both types of studied cells.