Detection ofChaetomium globosum,Ch. cochliodesandCh. rectangulareduring the Diversity Tracking of Mycotoxin-ProducingChaetomium-like Isolates Obtained in Buildings in Finland

The diversity ofChaetomium-like isolates in buildings in Finland is poorly documented. This paper describes a set of methods for rapid diversity tracking of 42 indoorChaetomium-like isolates. These isolates were categorized based on their fluorescence emission, ascomatal hair morphology, responses in three bioassays and resistance/sensitivity to the wetting agent Genapol X-080. Thirty-nine toxigenic isolates were identified [Ch. globosum(n= 35),Ch. cochliodes(n= 2) andCh. rectangulare(n= 2)]. These isolates were identified down to the species level bytef1 alpha gene sequencing. The major toxic substances in the ethanol extracts of theCh. globosumandCh. cochliodesstrains were chaetoglobosin, chaetoviridin A and C, chaetomugilin D and chaetomin, identified based on HPLC-UV and mass spectrometry data (MS and MS/MS). Ethanol extracts from pureCh. globosumcultures exhibited a toxicological profile in the boar sperm motility inhibition assay (BSMI), sperm membrane integrity damage assay (SMID) and inhibition of cell proliferation (ICP) assay, similar to that exhibited by pure chaetoglobosin A. Overall, differences in fluorescence, morphology, toxicity profile, mycotoxin production and sensitivity to chemicals were consistent with those intef1 alpha sequencing results for species identification. The results indicate the presence ofCh. cochliodesandCh. rectangularein Finnish buildings, representing a new finding.