Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitute 1% of all described fungal species.
Cryptococcus is a genus of fungi in the family Cryptococcaceae that includes both yeasts and filamentous species. The filamentous, sexual forms or teleomorphs were formerly classified in the genus Filobasidiella, while Cryptococcus was reserved for the yeasts. Most yeast species formerly referred to Cryptococcus have now been placed in different genera. The name Cryptococcus comes from the Greek for "hidden sphere". Some Cryptococcus species cause a disease called cryptococcosis.
Candida is a genus of yeasts. It is the most common cause of fungal infections worldwide and the largest genus of medically important yeast.
Malassezia is a genus of fungi. It is the sole genus in family Malasseziaceae, which is the only family in order Malasseziales, itself the single member of class Malasseziomycetes. Malassezia species are naturally found on the skin surfaces of many animals, including humans. In occasional opportunistic infections, some species can cause hypopigmentation or hyperpigmentation on the trunk and other locations in humans. Allergy tests for these fungi are available. It is believed French revolutionary Jean-Paul Marat suffered from a fungal infection from Malassezia restricta, which lead to his frequent bathing in a medicinal substance.
Rhodotorula is a genus of fungi in the class Microbotryomycetes. Most species are known in their yeast states which produce orange to red colonies when grown on Sabouraud's dextrose agar (SDA). The colour is the result of pigments that the yeast creates to block out certain wavelengths of light (620–750 nm) that would otherwise be damaging to the cell. Hyphal states, formerly placed in the genus Rhodosporidium, give rise to teliospores from which laterally septate basidia emerge, producing sessile basidiospores. Species occur worldwide and can be isolated from air, water, soil, and other substrates.
Trichosporon is a genus of anamorphic fungi in the family Trichosporonaceae. All species of Trichosporon are yeasts with no known teleomorphs. Most are typically isolated from soil, but several species occur as a natural part of the skin microbiota of humans and other animals. Proliferation of Trichosporon yeasts in the hair can lead to an unpleasant but non-serious condition known as white piedra. Trichosporon species can also cause severe opportunistic infections (trichosporonosis) in immunocompromised individuals.
The Tremellomycetes are a class of dimorphic fungi in the Agaricomycotina. Some species have gelatinous basidiocarps or (microscopically) a sacculate parenthesome. There are six orders, 17 families, and 39 genera in the Tremellomycetes. Tremellomycetes include yeasts, dimorphic taxa, and species that form complex fruiting bodies. Tremellomycetes include some fungi that are human and animal pathogens in the genera Cryptococcus, Naganishia, Papiliotrema, and Trichosporon and some fungi that are cultivated for food in the genera Tremella and Naematelia.
Antarctica is one of the most physically and chemically extreme terrestrial environments to be inhabited by lifeforms. The largest plants are mosses, and the largest animals that do not leave the continent are a few species of insects.
Cariamiformes is an order of primarily flightless birds that has existed for over 60 million years. The group includes the family Cariamidae (seriemas) and the extinct families Phorusrhacidae, Bathornithidae, Idiornithidae and Ameghinornithidae. Though traditionally considered a suborder within Gruiformes, both morphological and genetic studies show that it belongs to a separate group of birds, Australaves, whose other living members are Falconidae, Psittaciformes and Passeriformes.
Leucosporidium is a genus of fungi in the subdivision Pucciniomycotina. The genus comprises fungi that are mostly known from their yeast states, though some produce hyphal states in culture that give rise to teliospores from which auricularioid basidia emerge. Species known only from their anamorphic yeast states were formerly referred to the genus Leucosporidiella, but, following changes to the International Code of Nomenclature for algae, fungi, and plants, the practice of giving different names to teleomorph and anamorph forms of the same fungus was discontinued, meaning that Leucosporidiella became a synonym of the earlier name Leucosporidium. Species have been isolated predominantly from cold environments and are regarded as psychrotolerant.
The Kriegeriales are an order of fungi in the subdivision Pucciniomycotina. Most species are known only from their yeast states and can be found in a variety of habitats, ranging from arctic waters to tropical ferns. Hyphal states produce auricularioid basidia.
Deinococcus marmoris is a Gram-positive bacterium isolated from Antarctica. As a species of the genus Deinococcus, the bacterium is UV-tolerant and able to withstand low temperatures.
Phaeotremella foliacea is a species of fungus in the family Phaeotremellaceae. It produces brownish, frondose, gelatinous basidiocarps and is parasitic on the mycelium of Stereum sanguinolentum, a fungus that grows on dead attached and recently fallen branches of conifers. It is widespread in north temperate regions. In the UK it has the recommended English name leafy brain and has also been called jelly leaf and brown witch's butter. Prior to 2017, the name Tremella foliacea was also applied to similar-looking species on broadleaf trees, now distinguished as Phaeotremella frondosa and Phaeotremella fimbriata.
Naganishia is a genus of fungi in the family Filobasidiaceae. Species are currently only known from their yeast states, most of which were formerly referred to the genus Cryptococcus. Some 15 species have been described worldwide. Naganishia albida is an occasional human pathogen.
Naganishia antarctica is a yeast species that has been isolated from soil in Antarctica.
Naganishia adeliensis is a species of fungus in the family Filobasidiaceae. It is currently only known from its yeast state, isolated from decaying algae in Antarctica.
Naganishia albidosimilis is a species of fungus in the family Filobasidiaceae. It is currently only known from its yeast state, isolated from soil in Antarctica.
Naganishia albida is a species of fungus in the family Filobasidiaceae. It is currently only known from its yeast state. The species was originally isolated from the air in Japan, and has subsequently been isolated from dry moss in Portugal, grasshoppers in Portugal, and tubercular lungs.
Solicoccozyma is a genus of fungi in the family Piskurozymaceae. Species have only been isolated in their yeast states, several of which were formerly referred to the genus Cryptococcus, but can produce filamentous states with basidia in culture. Nine species have been described worldwide.
Mrakia is a genus of fungi in the order Cystofilobasidiales. The genus comprises yeasts, some of which have a hyphal state forming teliospores from which basidia arise. Mrakia species are typically psychrophilic, many originally isolated from glaciers and frigid environments, and are capable of low-temperature fermentation, making them of potential interest in brewing and bioremediation.
