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Metabolites of Trichoderma species isolated from damp building materials
David R McMullin1, Justin B Renaud2, Tharcisse Barasubiye3
1a Ottawa Carleton Institute of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
Abstract:
Buildings that have been flooded often have high concentrations of Trichoderma spores in the air while drying. Inhaled spores and spore and mycelial fragments contain large amounts of fungal glucan and natural products that contribute to the symptoms associated with indoor mould exposures. In this study, we considered both small molecules and peptaibol profiles of T. atroviride, T. koningiopsis, T. citrinoviride, and T. harzianum strains obtained from damp buildings in eastern Canada. Twenty-residue peptaibols and sorbicillin-derived metabolites (1-6) including a new structure, (R)-vertinolide (1), were characterized from T. citrinoviride. Trichoderma koningiopsis produced several koninginins (7-10), trikoningin KA V, and the 11-residue lipopeptaibols trikoningin KB I and trikoningin KB II. Trichoderma atroviride biosynthesized a mixture of 19-residue trichorzianine-like peptaibols, whereas T. harzianum produced 18-residue trichokindin-like peptaibols and the 11-residue harzianin HB I that was subsequently identified from the studied T. citrinoviride strain. Two α-pyrones, 6-pentyl-pyran-2-one (11) and an oxidized analog (12), were produced by both T. atroviride and T. harzianum. Aside from exposure to low molecular weight natural products, inhalation of Trichoderma spores and mycelial fragments may result in exposure to membrane-disrupting peptaibols. This investigation contributes to a more comprehensive understanding of the biologically active natural products produced by fungi commonly found in damp buildings.
Insights
Flooded buildings harbor Trichoderma fungi, releasing spores and fragments containing fungal glucans and natural products. This study identifies diverse small molecules and peptaibols from these common indoor molds.
Area of Science:
- Environmental Science
- Mycology
- Natural Products Chemistry
Background:
- Flooded buildings often exhibit high airborne Trichoderma spore concentrations.
- Inhaled fungal components like glucans contribute to indoor mold exposure symptoms.
- Trichoderma species are prevalent in damp indoor environments.
Purpose of the Study:
- To characterize the small molecules and peptaibols produced by Trichoderma strains from damp Canadian buildings.
- To identify specific fungal metabolites associated with indoor mold exposures.
- To understand the diversity of biologically active natural products from indoor Trichoderma species.
Main Methods:
- Isolation and chemical characterization of metabolites from four Trichoderma species (T. atroviride, T. koningiopsis, T. citrinoviride, T. harzianum).
- Analysis of small molecules and peptaibol profiles.
- Structure elucidation of novel compounds, including (R)-vertinolide.
Main Results:
- T. citrinoviride produced peptaibols and sorbicillin derivatives, including new compound (R)-vertinolide.
- T. koningiopsis yielded koninginins and lipopeptaibols.
- T. atroviride and T. harzianum biosynthesized distinct peptaibols and α-pyrones; harzianin HB I was found in both T. harzianum and T. citrinoviride.
Conclusions:
- Inhalation of Trichoderma spores and fragments exposes individuals to both low molecular weight natural products and membrane-disrupting peptaibols.
- This research expands the understanding of bioactive natural products from fungi commonly found in damp buildings.
- Identified metabolites may contribute to health effects associated with indoor mold exposure.