Yeasts are eukaryotic microorganisms classified as members of the fungus kingdom with 1,500 species currently identified and are estimated to constitute 1% of all described fungal species.
- 8.1: Overview of Fungi
- Fungi include yeasts, molds, and fleshy fungi. Fungi are are eukaryotic organisms and possess a cell wall. Most fungi are saprophytes, organisms that live off of decaying matter; a few are parasites, organisms that live off of living matter. A fungal infection is called a mycosis.
- 8.2: Yeasts
- Yeasts are eukaryotic unicellular fungi Some yeast are dimorphic in that they can grow as an oval, budding yeast, but under certain culture conditions, they may produce filament-like structures called hyphae similar to molds. Components of the yeast cell wall that function as pathogen-associated molecular patterns or PAMPs include lipoteichoic acids, zymosan, and mannose-rich glycans. These PAMPs bind to pattern-recognition receptors or PRRs on a variety of body defense cells.
- 8.3: Molds
- Molds are multinucleated, filamentous fungi composed of hyphae. Molds reproduce primarily by means of asexual reproductive spores. The dermatophytes are a group of molds that cause superficial mycoses of the hair, skin, and nails and utilize the protein keratin that is found in hair, skin, and nails, as a nitrogen and energy source. Dimorphic fungi may exhibit two different growth forms. Outside the body they grow as a mold, producing hyphae and asexual reproductive spores.
- 8.4: Fungal Pathogenicity
- Many of the same factors that enable bacteria to colonize the body also enable fungi to colonize. Many of the same factors that enable bacteria to harm the body also enable fungi to cause harm.
- 8.5: Chemotherapeutic Control of Fungi
- Because fungi, like human cells, are eukaryotic, there are far fewer chemotherapeutic agents that are selectively toxic for fungi than there are for prokaryotic bacteria. Most antifungal agents bind to or interfere with the synthesis of ergosterol, the sterol in their cytoplasmic membrane, altering membrane structure and function.
- 8.E: Fungi (Exercises)
- These are homework exercises to accompany Kaiser's "Microbiology" TextMap. Microbiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell (unicellular), cell clusters or no cell at all (acellular). This includes eukaryotes, such as fungi and protists, and prokaryotes. Viruses and prions, though not strictly classed as living organisms, are also studied.
Contributors and Attributions
Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS)