Beers of spontaneous fermentation use wild yeasts rather than cultivated ones. Anethole has potent antimicrobial properties, against bacteria, yeasts, and fungi. Saccharomyces is a genus of fungi that includes many species of yeasts. "Paramecia" feed on microorganisms like bacteria, algae, and yeasts. The toxicity of nickel to bacteria, yeasts, and fungi differs considerably. A warm, wet underarm may accommodate the growth of pathogenic bacteria, yeasts, and fungi. Flour naturally contains a variety of yeasts and bacterial spores. They contribute to the decomposition of dead vegetation, and feed on bacteria, yeasts, and fungi. Equivalent subunits are frequently numbered differently between bacteria, Archaea, yeasts and humans. Common organisms causing nail infections include yeasts and molds (particularly dermatophytes). These yeasts ferment well at low temperatures. HO demonstrates broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial spores. Fermentation starts spontaneously under the action of the natural yeasts from the grapes. With the exception of the yeasts, most fungi are obligate aerobes. Acidity levels of below pH 4.0 inhibit lactobacilli and favour acid-tolerant yeasts.