Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and K

The occurrence and toxin production of the opportunistic pathogen <em>Aspergillus calidoustus</em> in Finnish buildings is not well documented in the literature. We tracked and identified four <em>A. calidoustus</em> colonies cultivated from indoor settled dusts and revealed...

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Main Authors: Marja Johanna Salo, Tamás Marik, Ottó Bencsik, Raimo Mikkola, László Kredics, András Szekeres, Maria A. Andersson, Heidi Salonen, Jarek Kurnitski
Format: Article
Language:English
Published: MDPI AG 2019-11-01
Series:Toxins
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Online Access:https://www.mdpi.com/2072-6651/11/12/683
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author Marja Johanna Salo
Tamás Marik
Ottó Bencsik
Raimo Mikkola
László Kredics
András Szekeres
Maria A. Andersson
Heidi Salonen
Jarek Kurnitski
author_facet Marja Johanna Salo
Tamás Marik
Ottó Bencsik
Raimo Mikkola
László Kredics
András Szekeres
Maria A. Andersson
Heidi Salonen
Jarek Kurnitski
author_sort Marja Johanna Salo
collection DOAJ
description The occurrence and toxin production of the opportunistic pathogen <em>Aspergillus calidoustus</em> in Finnish buildings is not well documented in the literature. We tracked and identified four <em>A. calidoustus</em> colonies cultivated from indoor settled dusts and revealed the biological activities of crude biomass extracts. The toxic substances were identified as 6-epi-ophiobolin K, ophiobolin K, and ophiobolin G by high-performance liquid chromatography&#8722;mass spectrometry (HPLC-MS) based on chromatographic and mass spectrometry data (MS and MS/MS) on the crude extract of <em>A. calidoustus</em> strain MH34. A total of 29 fungal colonies collected from settled dust in an office room reported for indoor-air-related illnesses were screened for toxins that inhibited boar sperm motility in the BSMI (boar sperm motility inhibiting) assay and cell proliferation in the ICP (inhibition of cell proliferation) assays with PK-15 cells. Out of the 27 colonies tested as toxic, 12 colonies exhibiting conidiophores representative of the genera <i>Chaetomium</i>,<i> Penicillium</i>,<i> and Paecilomyces </i>were excluded from the study, while 13 colonies exhibited <em>Aspergillus-like</em> conidiophores. Biomass suspensions of these colonies were divided into two categories: Category 1 colonies (n = 4), toxic in the BSMI assay and the ICP assays, emitted blue fluorescence and grew at 37 &#176;C; Category 2 colonies (n = 9), only toxic in the ICP assay, emitted orange fluorescence and exhibited limited or no growth at 37 &#176;C. Colonies in Category 1 were pure-cultured, and the strains were named as MH4, MH21, MH34, MH36. Strain MH34 was identified as <em>A. calidoustus</em> by the internal transcribed spacer (ITS) sequences. Ethanol-soluble dry substances extracted from the biomass of the pure cultures exhibited a toxicological profile in the BSMI assay, SMID (sperm membrane integrity damage) assay, and ICP assay similar to that exhibited by pure ophiobolin A. Overall, the viable conidia of <em>A. calidoustus</em> in indoor settled dusts deserve attention when potentially hazardous mold species are monitored.
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spelling doaj.art-90ef5f9ee5df470e952b93df985ccabf2022-12-22T03:19:27ZengMDPI AGToxins2072-66512019-11-01111268310.3390/toxins11120683toxins11120683Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and KMarja Johanna Salo0Tamás Marik1Ottó Bencsik2Raimo Mikkola3László Kredics4András Szekeres5Maria A. Andersson6Heidi Salonen7Jarek Kurnitski8Department of Civil Engineering, Aalto University, Box 12100, FI-00076 Aalto, FinlandDepartment of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, 6727 Szeged, HungaryDepartment of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, 6727 Szeged, HungaryDepartment of Civil Engineering, Aalto University, Box 12100, FI-00076 Aalto, FinlandDepartment of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, 6727 Szeged, HungaryDepartment of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, 6727 Szeged, HungaryDepartment of Civil Engineering, Aalto University, Box 12100, FI-00076 Aalto, FinlandDepartment of Civil Engineering, Aalto University, Box 12100, FI-00076 Aalto, FinlandDepartment of Civil Engineering, Aalto University, Box 12100, FI-00076 Aalto, FinlandThe occurrence and toxin production of the opportunistic pathogen <em>Aspergillus calidoustus</em> in Finnish buildings is not well documented in the literature. We tracked and identified four <em>A. calidoustus</em> colonies cultivated from indoor settled dusts and revealed the biological activities of crude biomass extracts. The toxic substances were identified as 6-epi-ophiobolin K, ophiobolin K, and ophiobolin G by high-performance liquid chromatography&#8722;mass spectrometry (HPLC-MS) based on chromatographic and mass spectrometry data (MS and MS/MS) on the crude extract of <em>A. calidoustus</em> strain MH34. A total of 29 fungal colonies collected from settled dust in an office room reported for indoor-air-related illnesses were screened for toxins that inhibited boar sperm motility in the BSMI (boar sperm motility inhibiting) assay and cell proliferation in the ICP (inhibition of cell proliferation) assays with PK-15 cells. Out of the 27 colonies tested as toxic, 12 colonies exhibiting conidiophores representative of the genera <i>Chaetomium</i>,<i> Penicillium</i>,<i> and Paecilomyces </i>were excluded from the study, while 13 colonies exhibited <em>Aspergillus-like</em> conidiophores. Biomass suspensions of these colonies were divided into two categories: Category 1 colonies (n = 4), toxic in the BSMI assay and the ICP assays, emitted blue fluorescence and grew at 37 &#176;C; Category 2 colonies (n = 9), only toxic in the ICP assay, emitted orange fluorescence and exhibited limited or no growth at 37 &#176;C. Colonies in Category 1 were pure-cultured, and the strains were named as MH4, MH21, MH34, MH36. Strain MH34 was identified as <em>A. calidoustus</em> by the internal transcribed spacer (ITS) sequences. Ethanol-soluble dry substances extracted from the biomass of the pure cultures exhibited a toxicological profile in the BSMI assay, SMID (sperm membrane integrity damage) assay, and ICP assay similar to that exhibited by pure ophiobolin A. Overall, the viable conidia of <em>A. calidoustus</em> in indoor settled dusts deserve attention when potentially hazardous mold species are monitored.https://www.mdpi.com/2072-6651/11/12/683<i>aspergillus calidoustus</i>ophiobolinsindoor moldfluorescence
spellingShingle Marja Johanna Salo
Tamás Marik
Ottó Bencsik
Raimo Mikkola
László Kredics
András Szekeres
Maria A. Andersson
Heidi Salonen
Jarek Kurnitski
Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and K
Toxins
<i>aspergillus calidoustus</i>
ophiobolins
indoor mold
fluorescence
title Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and K
title_full Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and K
title_fullStr Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and K
title_full_unstemmed Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and K
title_short Screening Mold Colonies by Using Two Toxicity Assays Revealed Indoor Strains of <i>Aspergillus calidoustus</i> Producing Ophiobolins G and K
title_sort screening mold colonies by using two toxicity assays revealed indoor strains of i aspergillus calidoustus i producing ophiobolins g and k
topic <i>aspergillus calidoustus</i>
ophiobolins
indoor mold
fluorescence
url https://www.mdpi.com/2072-6651/11/12/683
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