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Toxic-metabolite-producing bacteria and fungus in an indoor environment
J Peltola1, M A Andersson, T Haahtela
1Division of Microbiology, Department of Applied Chemistry and Microbiology, University of Helsinki, FIN-00014 University of Helsinki, Finland. joanna.peltola@helsinki.fi
Abstract:
Toxic-metabolite-emitting microbes were isolated from the indoor environment of a building where the occupant was suffering serious building-related ill-health symptoms. Toxic substances soluble in methanol and inhibitory to spermatozoa at <10 microg (dry weight) ml(-1) were found from six bacterial isolates and one fungus. The substances from isolates of Bacillus simplex and from isolates belonging to the actinobacterial genera Streptomyces and Nocardiopsis were mitochondriotoxic. These substances dissipated the mitochondrial membrane potential (Deltapsi) of boar spermatozoa. The substances from the Streptomyces isolates also swelled the mitochondria. The substances from isolates of Trichoderma harzianum Rifai and Bacillus pumilus damaged the cell membrane barrier function of sperm cells.
Insights
Microbial toxins from indoor environments caused serious health issues. Certain bacteria and fungi emitted substances toxic to sperm cells, damaging mitochondria and cell membranes.
Area of Science:
- Environmental microbiology
- Toxicology
- Cell biology
Background:
- Building-related ill-health symptoms are a growing concern.
- Indoor environments can harbor toxic microorganisms.
- Microbial metabolites can pose health risks.
Purpose of the Study:
- To isolate and identify toxic-metabolite-emitting microbes from an indoor environment.
- To investigate the toxic effects of microbial substances on spermatozoa.
- To understand the mechanisms of microbial toxicity in relation to building-related illnesses.
Main Methods:
- Isolation of microbes from indoor building environments.
- Extraction of toxic substances soluble in methanol.
- Assessment of toxicity using boar spermatozoa, including mitochondrial membrane potential (Deltapsi) and cell membrane integrity assays.
- Identification of bacterial and fungal isolates.
Main Results:
- Six bacterial isolates and one fungus emitted toxic substances.
- Substances from Bacillus simplex, Streptomyces, and Nocardiopsis were mitochondriotoxic, dissipating mitochondrial membrane potential (Deltapsi).
- Substances from Streptomyces also caused mitochondrial swelling.
- Substances from Trichoderma harzianum and Bacillus pumilus damaged sperm cell membrane barrier function.
Conclusions:
- Indoor microbes can produce potent toxins affecting cellular functions.
- Mitochondrial and cell membrane damage in spermatozoa are key indicators of microbial toxicity.
- These findings link specific indoor microbial contaminants to building-related health problems.