''Capronia mansonii'' is a

mesophilic A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from . The optimum growth temperature for these organisms is 37°C. The term is mainly applied to microorganisms. Organi ...

black yeast that is a part of the

Herpotrichiellaceae Herpotrichiellaceae is a family of ascomycetous fungi within the order Chaetothyriales and within the class Eurotiomycetes. It contains 16 genera and about 270 species. The type genus of the family, ''Herpotrichiella'', is now synonymous with '' ...

. The species is uncommon in nature but is

saprotrophic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...

in nature and been discovered on decaying plant matter, particularly wood. This fungus is naturally found in the Netherlands and has successfully been cultured in lab. It is a teleomorph of the

ascomycota Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The def ...

division and possesses brown

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

History and taxonomy

''Capronia mansonii'' is a type of black yeast that was first discovered from an isolated strain in 1968. The fungus was originally described from a strain

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...

found in Norway by

Marie Beatrice Schol-Schwarz Marie Beatrice "Bea" Schol-Schwarz (12 July 1898 – 27 July 1969) was the Dutch phytopathologist who discovered the causal fungus of Dutch elm disease. She first studied pathogens afflicting peanuts and later the fungus '' Phialophora''. Bio ...

on an aspen tree, and it has not yet been described in situ. This fungus was the first species in Herpotrichiellaceae discovered to create ascomata in an isolated culture. It is one of the only five species out of thirty ''Capronia'' species that has successfully produced ascomata in vitro. The

basionym In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botan ...

for this species is ''Dictyotrichiella mansonii''. Its

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 ...

is thought to be ''Exophiala mansonii'' but uncertainty and discourse remains. The original anamorph was first thought to be '' Rhinocladiella atrovirens'' and then ''Exophiala castellanii'' An analysis of rRNA gene sequences concluded that ''C. mansonii'' is the same biological species as ''E. castellanii''. ''Capronia mansonii'' is often misidentified as its sister species ''Capronia munkii'' but can be differentiated by its larger and thicker cell walls and more frequent ascospores that transversely septate. It is also differentiated from its anamorph because it lacks

conidia A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the ...

, slimy colonies, and aerial

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 ...

Growth and morphology

This fungus is a teleomorph or sexual form that is formed in vitro. This species has yet to be described in situ. The fungus is thought to be closely related to ''

Exophiala dermatitidis ''Exophiala dermatitidis'' is a thermophilic black yeast, and a member of the Herpotrichiellaceae. While the species is only found at low abundance in nature, metabolically active strains are commonly isolated in saunas, steam baths, and dish wa ...

'', and is often hypothesized in literature to be the teleomorph of ''E. dermatitidis''. The fungus is a part of the ascomycota phylum, also commonly defined as sac fungi. This phylum is often defined by its possession of

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

, a microscope sexual structure that produces non-motile spores called

ascospores An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or ...

. The asci of C. mansonii produce 8 ascospores upon germination. These ascospores begin with a glassy transparent appearance and then progress to a more grey-yellow, olive, and finally brown colour. These ascospores have 4–5 transverse thick-walled

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 ...

and 1 incomplete longitudinal septum. The spores have been described in literature as not tight at the septa. Juvenile asci have thicker, longer, and more lightly coloured ascus walls whereas as fully matured asci form thinner dark brown walls that are filled with ascospores. The ascomatal wall itself can range from a brown-yellow to a light brown colour which is commonly seen in other black yeasts.

Physiology and reproduction

This mesophilic fungus has been successfully cultured by Untereiner at room temperature ranging from 20–25 °C. ''C. mansonii'' has also been observed in a yeast budding form. This fungus has a homothallic breeding system indicating that it does not need a partner to sexually reproduce. The ascospores of this fungus have been described to germinate within 12 hours on Oatmeal Agar. They appear slimy and resemble yeast within 48 hours, reaching full maturity at 16 weeks. The ascomata that have been grown in lab have been shown to fully mature and develop septae but are unable to produce asci and ascospores. Artificial daylight is thought to be the limiting factor that prevents the production of asci. Further replications of the above experiments revealed that the structure formed may actually be a

pseudothecium An ascocarp, or ascoma (), is the fruiting body (sporocarp (fungi), sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded ascus, asci, each of which typically contains four to eight asco ...

, an ascocarp that resembles a ascocarp but whose asci do not organize into a

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some ...

. The pseudothecia grew in abundance and also failed to produce ascospores.

Habitat and ecology

Members of the ''Capronia'' family are described as saprotrophic meaning they get their nutrients from decaying matter. Strains of this fungus have been found on various plant hosts, particularly on their leaves. They are regularly found on other decaying ascomycota and

basidiomycota Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

in the Netherlands, particularly on the wood of Populus tremula. The holotype was discovered on the stems of a ''

Lupinus polyphyllus ''Lupinus polyphyllus'', the large-leaved lupine, big-leaved lupine, many-leaved lupine, blue-pod lupine, or, primarily in cultivation, garden lupin, is a species of lupine (lupin) native to western North America from southern Alaska and Britis ...

'' by Schol-Schwarz in 1968. This fungus has occasionally been found on fresh sausages consisting of pork, beef, or mixed meats. They remain unstable on meat and are unable to persist for more than three days in the presence of other lactic acid bacteria.

References

{{Taxonbar , from = Q10442302 Eurotiomycetes Fungi described in 1968 Fungi of Europe