''Trichosporon'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

anamorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Trichosporonaceae The Trichosporonaceae are a family of fungi in the order Trichosporonales. The family currently contains six genera. Species are not known to produce basidiocarps (fruit bodies), but exist as yeasts or produce septate hyphae with arthroconidia. S ...

. All

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of ''Trichosporon'' are

yeast 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 constitut ...

s with no known

teleomorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

s (sexual states). Most are typically isolated from soil, but several species occur as a natural part of the

skin microbiota Skin flora, also called skin microbiota, refers to microbiota (communities of microorganisms) that reside on the skin, typically human skin. Many of them are bacteria of which there are around 1,000 species upon human skin from nineteen phyla.P ...

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 White piedra (or tinea blanca) is a mycosis of the hair caused by several species of fungi in the genus '' Trichosporon''. It is characterized by soft nodules composed of yeast cells and arthroconidia that encompass hair shafts. Diagnosis White ...

. ''Trichosporon'' species can also cause severe

opportunistic infection An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune ...

s (

trichosporonosis Trichosporonosis is a systemic disease associated with fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. ...

) in

immunocompromised Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...

individuals.

Taxonomy

The genus was first described by the German

dermatologist Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medical ...

Gustav Behrend Gustav Behrend (10 January 1847 – 1925) was a German dermatologist who was a native of Neustettin (today- Szczecinek, Poland). In 1870 he received his medical doctorate at the University of Berlin, and during the Franco-Prussian War, he served ...

in 1890, based on yeasts isolated from the hairs of a

moustache A moustache (; en-US, mustache, ) is a strip of facial hair grown above the upper lip. Moustaches have been worn in various styles throughout history. Etymology The word "moustache" is French, and is derived from the Italian ''mustaccio'' ...

where they were causing the condition known as "

". Behrend called his new species ''

Trichosporon ovoides ''Trichosporon'' is a genus of anamorphic fungi in the family (biology), family Trichosporonaceae. All species of ''Trichosporon'' are yeasts with no known teleomorphs (sexual states). Most are typically isolated from soil, but several species o ...

''.

Friedrich Küchenmeister Gottlieb Heinrich Friedrich Küchenmeister (22 January 1821, Buchheim (now Bad Lausick) – 13 April 1890 Dresden) was a German physician. Life Küchenmeister studied medicine in Leipzig and Prague, and in 1846 he became a general practitioner i ...

and Rabenhorst had, however, previously described a species in 1867 from the hairs of a wig. They thought that the organism was an

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mi ...

and placed it in the genus ''

Pleurococcus ''Pleurococcus'' is a genus of green algae in the family Chaetophoraceae Chaetophoraceae is a family of green algae in the order Chaetophorales. Genera * '' Arthrochaete'' * '' Caespitella'' * '' Cedercreutziella'' * '' Chaetomnion'' * '' C ...

'' as ''Pleurococcus beigelii''. The French mycologist

Vuillemin Vuillemin is a surname. Notable people with the surname include: * Alexandre Vuillemin (1812–1880), French cartographer *David Vuillemin (born 1977), French motorcycle racer *Jean Vuillemin, French computer scientist *Jean-Claude Vuillemin (born ...

later realized it was a

and transferred it to the genus ''Trichosporon'', considering it to be an earlier name for ''Trichosporon ovoides''. Over 100 additional yeast species were referred to ''Trichosporon'' by later authors. With the advent of

DNA sequencing DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

, however, it became clear that many of these additional species belonged in other genera. Based on

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analysis of DNA sequences, 12 species are now accepted in the genus. DNA sequencing has also shown that white piedra can be caused by more than one ''Trichoporon'' species. As a result, ''Trichosporon beigelii'' has become a name of uncertain application. McPartland & Goff selected a

neotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

strain that makes ''T. beigelii'' synonymous with '' Cutaneotrichosporon cutaneum''. Guého and others, however, have argued that ''T. beigelii'' should be discarded (as a dubious name) and Behrend's original ''T. ovoides'' (for which a neotype strain has also been selected) should become the type. As a result of this uncertainty, the name ''T. beigelii'' is now obsolete.

Description and habitat

''Trichosporon'' species are distinguished microscopically by having yeast cells that germinate to produce hyaline

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

e that disarticulate at the

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five coun ...

, the hyphal compartments acting as

arthroconidia Arthroconidia are a type of fungal spore typically produced by segmentation of pre-existing fungal hyphae. Background These spores are asexual and are generally not as durable and environmentally persistent as, for instance, bacterial endospores o ...

(asexual propagules). No

ic (sexual) states are known. Species of ''Trichosporon'' and related genera are widespread and have been isolated from a wide range of substrates, including human hair (''Trichosporon ovoides''), soil (''Cutaneotrichosporon guehoae''),

cabbage Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nb ...

s (''Apiotrichum brassicae''),

cheese Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, ...

(''T. caseorum''),

scarab beetles The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...

(''Apiotrichum scarabaeorum''),

parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...

droppings (''T. coremiiforme''), and

sea water Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approx ...

(''Cutaneotrichosporon dermatis'').

Human pathogens

Several ''Trichosporon'' species occur naturally as part of the microbiota of human skin. Occasionally, particularly in circumstances of high humidity, the fungus can proliferate, causing an unpleasant but harmless hair condition known as

. Soft, pale nodules containing yeast cells and arthroconidia form on hairs of the scalp and body. The species responsible include ''Trichosporon ovoides'', '' T. inkin'', '' T. asahii'', ''Cutaneotrichosporon mucoides'', ''T. asteroides'', and '' Cutaneotrichosporon cutaneum''. The obsolete name ''T. beigelii'' was formerly applied to all or any of these species. Much more serious

s, collectively called

, have been reported in

individuals. Species said to be agents of trichosporonosis are ''T. asahii'', ''T. asteroides'', '' Cutaneotrichosporon cutaneum'', ''Cutaneotrichosporon dermatis'', ''T. dohaense'', ''T. inkin'', ''Apiotrichum loubieri'', ''Cutaneotrichosporon mucoides'', and ''T. ovoides''.

Species

*'' Trichosporon aquatile'' *'' Trichosporon asahii'' *'' Trichosporon asteroides'' *'' Trichosporon caseorum'' *'' Trichosporon coremiiforme'' *'' Trichosporon dohaense'' *'' Trichosporon faecale'' *'' Trichosporon inkin'' *'' Trichosporon insectorum'' *'' Trichosporon japonicum'' *''

Trichosporon lactis ''Trichosporon'' is a genus of anamorphic fungi in the family Trichosporonaceae. All species of ''Trichosporon'' are yeasts with no known teleomorphs (sexual states). Most are typically isolated from soil, but several species occur as a natural ...

'' *''

References

External links

* {{Taxonbar, from=Q3272399 Tremellomycetes Yeasts