Cryptococcus: Difference between revisions

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'''''Cryptococcus''''' is a [[genus]] of fungi in the [[family (biology)|family]] [[Cryptococcaceae]] that includes both [[yeast]]s and filamentous [[species]]. The filamentous, sexual forms or [[teleomorph]]s 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. Some ''Cryptococcus'' species cause a disease called [[cryptococcosis]].
'''''Cryptococcus''''' (from [[Ancient Greek]] [[wikt:κρυπτός|κρυπτός]] (''kruptós''), meaning "hidden", and [[wikt:κόκκος|κόκκος]] (''kókkos''), meaning "grain"<ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2600220/</ref>) is a [[genus]] of [[fungi]] in the [[family (biology)|family]] [[Cryptococcaceae]] that includes both [[yeast]]s and filamentous [[species]]. The filamentous, sexual forms or [[teleomorph]]s 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. Some ''Cryptococcus'' species cause a disease called [[cryptococcosis]].


==Taxonomy==
==Taxonomy==
The genus was described by French mycologist [[Jean Paul Vuillemin]] in 1901, when he failed to find [[ascospore]]s characteristic of the genus ''[[Saccharomyces]]'' in the yeast previously known as ''Saccharomyces neoformans''.<ref name="Kurtzman" /> Over 300 additional names were subsequently added to the genus, almost all of which were later removed following [[Molecular phylogenetics|molecular]] research based on [[cladistic]] analysis of [[DNA sequences]]. As a result, some ten species are currently recognized in ''Cryptococcus''.<ref name="Liu2015"/>
The genus was described by French mycologist [[Jean Paul Vuillemin]] in 1901, when he failed to find [[ascospore]]s characteristic of the genus ''[[Saccharomyces]]'' in the yeast previously known as ''Saccharomyces neoformans''.<ref name="Kurtzman" /> Over 300 additional names were subsequently added to the genus, almost all of which were later removed following [[Molecular phylogenetics|molecular]] research based on [[cladistic]] analysis of [[DNA sequences]]. As a result, some 10 species are recognized in ''Cryptococcus''.<ref name="Liu2015"/>


The teleomorph was first described in 1975 by [[K.J. Kwon-Chung]], who obtained cultures of the [[type species]], ''Filobasidiella neoformans'', by crossing strains of the yeast ''[[Cryptococcus neoformans]]''. She was able to observe [[basidia]] similar to those of the genus ''[[Filobasidium]]'', hence the name ''Filobasidiella'' for the new genus.<ref name="Kwon-Chung"/> 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 ''Filobasidiella'' became a synonym of the earlier name ''Cryptococcus''.
The teleomorph was first described in 1975 by [[K.J. Kwon-Chung]], who obtained cultures of the [[type species]], ''Filobasidiella neoformans'', by crossing strains of the yeast ''[[Cryptococcus neoformans]]''. She was able to observe [[basidia]] similar to those of the genus ''[[Filobasidium]]'', hence the name ''Filobasidiella'' for the new genus.<ref name="Kwon-Chung"/> 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 ''Filobasidiella'' became a synonym of the earlier name ''Cryptococcus''.
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<ref name="Kwon-Chung">{{cite journal |doi=10.2307/3758842 |author=Kwon-Chung KJ. |year=1975 |title=A new genus, ''Filobasidiella'', the perfect state of ''Cryptococcus neoformans'' |jstor=3758842 |journal=Mycologia |volume=67 |issue= 6|pages=1197–1200 |pmid=765816}}</ref>
<ref name="Kwon-Chung">{{cite journal |doi=10.2307/3758842 |author=Kwon-Chung KJ. |year=1975 |title=A new genus, ''Filobasidiella'', the perfect state of ''Cryptococcus neoformans'' |jstor=3758842 |journal=Mycologia |volume=67 |issue= 6|pages=1197–1200 |pmid=765816}}</ref>


<ref name="Kurtzman">{{cite book | url=https://books.google.com/books?id=bnWQsv2eTcEC&dq=%22Saccharomyces+neoformans%22&pg=PA660 | title=The Yeasts - A Taxonomic Study | isbn=9780080542690 | last1=Kurtzman | first1=Cletus P. | last2=Fell | first2=Jack W. | date=20 March 1998 | publisher=Elsevier }}</ref>
<ref name="Kurtzman">{{cite book | url=https://books.google.com/books?id=bnWQsv2eTcEC&dq=%22Saccharomyces+neoformans%22&pg=PA660 | title=The Yeasts - A Taxonomic Study | isbn=978-0-08-054269-0 | last1=Kurtzman | first1=Cletus P. | last2=Fell | first2=Jack W. | date=20 March 1998 | publisher=Elsevier }}</ref>


<ref name="Liu2015">{{cite journal |vauthors=Liu XZ, Wang QM, Göker M, Groenewald M, Kachalkin AV, Lumbsch HT, Millanes AM, Wedin M, Yurkov AM, Boekhout T, Bai FY |year=2015 |title=Towards an integrated phylogenetic classification of the Tremellomycetes |journal=Studies in Mycology |volume=81 |pages=85–147 |doi=10.1016/j.simyco.2015.12.001|pmid=26955199 |pmc=4777781 }}</ref>
<ref name="Liu2015">{{cite journal |vauthors=Liu XZ, Wang QM, Göker M, Groenewald M, Kachalkin AV, Lumbsch HT, Millanes AM, Wedin M, Yurkov AM, Boekhout T, Bai FY |year=2015 |title=Towards an integrated phylogenetic classification of the Tremellomycetes |journal=Studies in Mycology |volume=81 |pages=85–147 |doi=10.1016/j.simyco.2015.12.001|pmid=26955199 |pmc=4777781 }}</ref>
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<ref name="Findley2009">{{cite journal |doi=10.1128/EC.00373-08 |vauthors=Findley K, Rodriguez-Carres M, Metin B, Kroiss J, Fonseca A, Vilgalys R, Heitman J |year=2009 |title=Phylogeny and phenotypic characterization of pathogenic ''Cryptococcus'' species and closely related saprobic taxa in the Tremellales |journal=Eukaryotic Cell |volume=8 |issue=3 |pages=353–361 |pmid=19151324 |pmc=2653247}}</ref>
<ref name="Findley2009">{{cite journal |doi=10.1128/EC.00373-08 |vauthors=Findley K, Rodriguez-Carres M, Metin B, Kroiss J, Fonseca A, Vilgalys R, Heitman J |year=2009 |title=Phylogeny and phenotypic characterization of pathogenic ''Cryptococcus'' species and closely related saprobic taxa in the Tremellales |journal=Eukaryotic Cell |volume=8 |issue=3 |pages=353–361 |pmid=19151324 |pmc=2653247}}</ref>


<ref name="Cogliati2013">{{cite journal | vauthors = Cogliati M | title = Global Molecular Epidemiology of ''Cryptococcus neoformans'' and ''Cryptococcus gattii'': An Atlas of the Molecular Types | journal = Scientifica | volume = 2013 | pages = 675213 | date = 2013 | pmid = 24278784 | pmc = 3820360 | doi = 10.1155/2013/675213 | doi-access = free }}</ref>  
<ref name="Cogliati2013">{{cite journal | vauthors = Cogliati M | title = Global Molecular Epidemiology of ''Cryptococcus neoformans'' and ''Cryptococcus gattii'': An Atlas of the Molecular Types | journal = Scientifica | volume = 2013 | article-number = 675213 | date = 2013 | pmid = 24278784 | pmc = 3820360 | doi = 10.1155/2013/675213 | doi-access = free }}</ref>  
    
    
<ref name="Samson">{{cite journal |vauthors=Samson RA, Stalpers JA, Weijman AC |year=1983 |title=On the taxonomy of the entomogenous fungus ''Filobasidiella arachnophila'' |journal=Antonie van Leeuwenhoek |volume=49 |issue=4–5 |pages=447–456 |pmid=6651289|doi=10.1007/BF00399323|s2cid=2752286 |url=https://link.springer.com/article/10.1007/BF00399323|url-access=subscription }}</ref>
<ref name="Samson">{{cite journal |vauthors=Samson RA, Stalpers JA, Weijman AC |year=1983 |title=On the taxonomy of the entomogenous fungus ''Filobasidiella arachnophila'' |journal=Antonie van Leeuwenhoek |volume=49 |issue=4–5 |pages=447–456 |pmid=6651289|doi=10.1007/BF00399323|s2cid=2752286 |url=https://link.springer.com/article/10.1007/BF00399323|url-access=subscription }}</ref>
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<ref name="Hagen">{{cite journal |vauthors=Hagen F, Khayhan K, Theelen B, et al |year=2015 |title=Recognition of seven species in the ''Cryptococcus gattii/Cryptococcus neoformans'' species complex |journal=Fungal Genetics and Biology |volume=78 |pages=16–48 |doi=10.1016/j.fgb.2015.02.009|pmid=25721988 |doi-access=free }}</ref>
<ref name="Hagen">{{cite journal |vauthors=Hagen F, Khayhan K, Theelen B, et al |year=2015 |title=Recognition of seven species in the ''Cryptococcus gattii/Cryptococcus neoformans'' species complex |journal=Fungal Genetics and Biology |volume=78 |pages=16–48 |doi=10.1016/j.fgb.2015.02.009|pmid=25721988 |doi-access=free }}</ref>


<ref name="Rodriguez-Carres">{{cite journal |vauthors=Rodriguez-Carres M, Findley K, Sun S, Dietrich FS, Heitman J |year=2010 |title=Morphological and genomic characterization of ''Filobasidiella depauperata'': a homothallic sibling species of the pathogenic ''Cryptococcus'' species complex |journal=PLOS ONE |volume= 5 |issue=3 |doi=10.1371/journal.pone.0009620 |pmc=2835752 |pmid=20224779 |pages=e9620|bibcode=2010PLoSO...5.9620R |doi-access=free }}</ref>
<ref name="Rodriguez-Carres">{{cite journal |vauthors=Rodriguez-Carres M, Findley K, Sun S, Dietrich FS, Heitman J |year=2010 |title=Morphological and genomic characterization of ''Filobasidiella depauperata'': a homothallic sibling species of the pathogenic ''Cryptococcus'' species complex |journal=PLOS ONE |volume= 5 |issue=3 |doi=10.1371/journal.pone.0009620 |pmc=2835752 |pmid=20224779 |article-number=e9620|bibcode=2010PLoSO...5.9620R |doi-access=free }}</ref>


<ref name="Ginns&Bernicchia">{{cite journal |vauthors=Ginns J, Bernicchia A |year=2000 |title=''Filobasidiella lutea'': parasitism of ''Hypochnicium vellereum'' |journal=Karstenia |volume=40 |issue= 1–2|pages=49–51|doi=10.29203/ka.2000.351 |doi-access=free }}</ref>
<ref name="Ginns&Bernicchia">{{cite journal |vauthors=Ginns J, Bernicchia A |year=2000 |title=''Filobasidiella lutea'': parasitism of ''Hypochnicium vellereum'' |journal=Karstenia |volume=40 |issue= 1–2|pages=49–51|doi=10.29203/ka.2000.351 |doi-access=free }}</ref>
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<ref name="Sivakumaran">{{cite journal |doi=10.1023/A:1023309311643 |vauthors=Sivakumaran S, Bridge P, Roberts P |year=2002 |title=Genetic relatedness among ''Filobasidiella'' species |journal=Mycopathologia |volume=156 |issue=3 |pages=157–162 |pmid=12749578|s2cid=41798563 }}</ref>
<ref name="Sivakumaran">{{cite journal |doi=10.1023/A:1023309311643 |vauthors=Sivakumaran S, Bridge P, Roberts P |year=2002 |title=Genetic relatedness among ''Filobasidiella'' species |journal=Mycopathologia |volume=156 |issue=3 |pages=157–162 |pmid=12749578|s2cid=41798563 }}</ref>


<ref name="Findley2012">{{cite journal |vauthors=Findley K, Sun S, Fraser JA, Hsueh Y, Averette AF, Li W, Dietrich FS, Heitman J |year=2012 |title=Discovery of a modified tetrapolar sexual cycle in ''Cryptococcus amylolentus'' and the evolution of MAT in the ''Cryptococcus'' species complex |journal=PLOS Genetics |volume=8 |issue=2 |pages=e1002528 |doi=10.1371/journal.pgen.1002528|pmid=22359516 |pmc=3280970 |doi-access=free }}</ref>
<ref name="Findley2012">{{cite journal |vauthors=Findley K, Sun S, Fraser JA, Hsueh Y, Averette AF, Li W, Dietrich FS, Heitman J |year=2012 |title=Discovery of a modified tetrapolar sexual cycle in ''Cryptococcus amylolentus'' and the evolution of MAT in the ''Cryptococcus'' species complex |journal=PLOS Genetics |volume=8 |issue=2 |article-number=e1002528 |doi=10.1371/journal.pgen.1002528|pmid=22359516 |pmc=3280970 |doi-access=free }}</ref>
}}
}}


Latest revision as of 19:08, 13 December 2025

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Cryptococcus (from Ancient Greek κρυπτός (kruptós), meaning "hidden", and κόκκος (kókkos), meaning "grain"[1]) 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. Some Cryptococcus species cause a disease called cryptococcosis.

Taxonomy

The genus was described by French mycologist Jean Paul Vuillemin in 1901, when he failed to find ascospores characteristic of the genus Saccharomyces in the yeast previously known as Saccharomyces neoformans.[2] Over 300 additional names were subsequently added to the genus, almost all of which were later removed following molecular research based on cladistic analysis of DNA sequences. As a result, some 10 species are recognized in Cryptococcus.[3]

The teleomorph was first described in 1975 by K.J. Kwon-Chung, who obtained cultures of the type species, Filobasidiella neoformans, by crossing strains of the yeast Cryptococcus neoformans. She was able to observe basidia similar to those of the genus Filobasidium, hence the name Filobasidiella for the new genus.[4] 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 Filobasidiella became a synonym of the earlier name Cryptococcus.

General characteristics

The cells of species that produce yeasts are covered in a thin layer of glycoprotein capsular material that has a gelatin-like consistency, and that among other functions, serves to help extract nutrients from the soil. The C. neoformans capsule consists of several polysaccharides, of which the major one is the immunomodulatory polysaccharide called glucuronoxylomannan (GXM).[5] GXM is made up of the monosaccharides glucuronic acid, xylose and mannose and can also contain O-acetyl groups. The capsule functions as the major virulence factor in cryptococcal infection and disease.[6]

Some Cryptococcus species have a huge diversity at the infraspecific level with different molecular types based on their genetic differences, mainly due to their geographical distribution, molecular characteristics, and ecological niches.[7]

Cryptococcus species are not known to produce distinct, visible fruitbodies. All teleomorph forms appear to be parasites of other fungi. In teleomorphs the hyphae are colourless, are clamped or unclamped, and bear haustorial cells with filaments that attach to the hyphae of host fungi.[8][9] The basidia are club-shaped and highly elongated. Spores arise in succession from four loci at the apex (which is sometimes partly septate). These spores are passively released and may remain on the basidium in chains, unless disturbed.[4] In the type species, the spores germinate to form yeast cells, but yeast states are not known for all species.

Habitat, distribution and species

File:Cryptococcus.jpg
Field stain showing Cryptococcus species in lung tissue

Script error: No such module "Labelled list hatnote". Cryptococcus neoformans is cosmopolitan and is the most prominent medically important species. It is best known for causing a severe form of meningitis and meningoencephalitis in people with HIV/AIDS. It may also infect organ-transplant recipients and people receiving certain cancer treatments.[10] In its yeast state C. neoformans is found in the droppings of wild birds, often pigeons; when dust of the droppings is stirred up, it can infect humans or pets that inhale the dust. Infected humans and animals do not transmit their infection to others.[10] The taxonomy of C. neoformans has been reviewed: it has now been divided into two species: Cryptococcus neoformans sensu stricto and Cryptococcus deneoformans.[11][3]

Script error: No such module "Labelled list hatnote". Cryptococcus gattii (formerly C. neoformans var. gattii) is endemic to tropical parts of the continent of Africa and Australia. It is capable of causing disease in non-immunocompromised people. In its yeast state it has been isolated from eucalyptus trees in Australia. The taxonomy of C. gattii has been reviewed; it has now been divided into five species: C. gattii sensu stricto, C. bacillisporus, C. deuterogattii, C. tetragattii, and C. decagattii.[11][3]

Cryptococcus depauperatus is parasitic on Lecanicillium lecanii, an entomopathogenic fungus, and is known from Sri Lanka, England, the Netherlands, the Czech Republic, and Canada.[9][12] It is not known to produce a yeast state.[13] This species grows as long, branching filaments and is self-fertile, i.e. it is homothallic.[14] It can reproduce sexually with itself throughout its life cycle.[14]

Cryptococcus luteus is parasitic on Granulobasidium vellereum, a corticioid fungus, and is known from England and Italy.[15] It too is not known to produce a yeast state.[16]

Cryptococcus amylolentus was originally isolated as a yeast from beetle tunnels in South African trees. It forms a basidia-bearing teleomorph in culture.[17]

As of April 2025Script error: No such module "Check for unknown parameters"., Species Fungorum (in the Catalogue of Life) accept 41 species of Cryptococcus:[18]

References

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  1. ↑ https://pmc.ncbi.nlm.nih.gov/articles/PMC2600220/
  2. ↑ Script error: No such module "citation/CS1".
  3. ↑ a b c Script error: No such module "Citation/CS1".
  4. ↑ a b Script error: No such module "Citation/CS1".
  5. ↑ Script error: No such module "Citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ Script error: No such module "Citation/CS1".
  9. ↑ a b Script error: No such module "Citation/CS1".
  10. ↑ a b Script error: No such module "citation/CS1".
  11. ↑ a b Script error: No such module "Citation/CS1".
  12. ↑ Script error: No such module "Citation/CS1".
  13. ↑ Script error: No such module "Citation/CS1".
  14. ↑ a b Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "Citation/CS1".
  17. ↑ Script error: No such module "Citation/CS1".
  18. ↑ Template:Catalogue of Life

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