{{Short description|Species of fungus}} {{Speciesbox | image = Scopulariopsis brevicaulis.jpg | genus = Microascus | species = brevicaulis | authority = S.P. Abbott (1998) | synonyms = ''Penicillium brevicaule'' <small>Sacc. (1886)</small><br> ''Scopulariopsis brevicaulis'' <small>(Sacc.) Bainier (1907)</small> }}
'''''Microascus brevicaulis''''' is a microfungus in the Ascomycota.<ref>{{cite web|title=MycoBank in English|url=http://www.mycobank.org/BioloMICS.aspx?Table=Mycobank&Rec=36461&Fields=All|access-date=23 October 2013}}</ref><ref>Kirk et al., p. 55.</ref> It is the teleomorph form of ''Scopulariopsis brevicaulis.'' ''Microascus brevicaulis'' occurs world-wide as a saprotroph in soil, a common agent of biodeterioration, an irregular plant pathogen, and an occasional agent of human nail infection.<ref name="onions1991">{{cite book|last=Onions|first=A.H.S., Allsopp D., Eggins H.O.W.|title=Smith's Introduction to industrial mycology.|publisher=Cambridge University Press|year=1991|isbn=978-0521427821|edition=7th|location=Cambridge, UK}}</ref><ref name="lee2012">{{cite journal|last=Lee|first=Myung Hoon|author2=Hwang, Sung Min|author3=Suh, Moo Kyu|author4=Ha, Gyoung Yim|author5=Kim, Heesoo|author6=Park, Jeong Young|year=2012|title=Onychomycosis caused by Scopulariopsis brevicaulis: Report of Two Cases|journal=Annals of Dermatology|volume=24|issue=2|pages=209–213|doi=10.5021/ad.2012.24.2.209|pmc=3346915|pmid=22577275}}</ref>
==Name== Most of the discussion of this fungus in the scientific and medical literature has referred to the fungus using the name of its asexual form, or anamorph, ''Scopulariopsis brevicaulis''.<ref name="hawksworth2011">{{cite journal | last1 = Hawksworth | first1 = D. L. | year = 2011 | title = A new dawn for the naming of fungi: impacts of decisions made in Melbourne in July 2011 on the future publication and regulation of fungal names | journal = MycoKeys | issue = 2 | pages = 7–20 | doi = 10.3897/mycokeys.1.2062 | pmid = 22679600 | pmc = 3359813 | doi-access = free }}</ref> However, a sexual form (teleomorph) named ''Microascus brevicaulis'' was recently described.<ref name="abbott1998">{{cite journal|last=Abbott|first=Sean P.; Sigler, L.; Currah, R. S.|author2=Sigler, Lynne |author3=Currah, R. S. |title=Microascus brevicaulis sp. nov., the Teleomorph of Scopulariopsis brevicaulis, Supports Placement of Scopulariopsis with the Microascaceae|journal=Mycologia|date=March 1998|volume=90|issue=2|pages=297|doi=10.2307/3761306|jstor=3761306 |s2cid=85266835 }}</ref> Under the current revision of ''International Code of Nomenclature for Algae, Fungi, and Plants'', as articulated in the [http://www.iapt-taxon.org/nomen/main.php Shenzhen Code 2018], it remains unclear which name this fungus will ultimately take.<ref name="hawksworth2011" /> Until further clarification, ''Microascus brevicaulis'' is considered the most recent, accepted name.<ref name="abbott1998" />
Bartolomeo Gosio discovered in 1890 that under wet conditions ''M. brevicaulis'' produces significant amounts of trimethylarsine via biomethylation of inorganic pigments especially Paris green or Scheele's Green used in indoor wallpapers which is then released into the air.<ref>{{cite journal | author= William R. Cullen, Ronald Bentley | title = The toxicity of trimethylarsine: an urban myth | journal = J. Environ. Monit. | year = 2005 | volume = 7 | issue = 1 | pages = 11–15 | doi = 10.1039/b413752n | pmid= 15693178 }}</ref>
==Morphology== ''Microascus brevicaulis'' is a common mold. When cultured at a temperature of 25 °C on potato dextrose agar it forms white colonies which become powdery and/or granular as they mature. Under such conditions the fungus can grow rapidly, expanding as much as 4.5 - 5.5 cm within one week.<ref name=drfungus>{{cite web|last=McGinnis|first=M|title=Scopulariopsis brevicaulis|url=http://www.doctorfungus.org/thefungi/Scopulariopsis_brevicaulis.php|work=Doctorfungus|access-date=19 November 2013|url-status=dead|archive-url=https://archive.today/20130414185401/http://www.doctorfungus.org/thefungi/Scopulariopsis_brevicaulis.php|archive-date=14 April 2013}}</ref> The hyphae of ''M. brevicaulis'' are hyaline (transparent) and septate (separated into segments by cross-walls). The anamorph has conidia that are flattened on the base and tapered at the apex, resembling a boat keel in cross-section or a pontifical mitre.<ref name=onions1991/> The conidia are produced in chains from cells known as annelides, phialide-like cells that elongate with each successive conidium produced.<ref>{{Cite web |url=http://www.mycology.adelaide.edu.au/virtual/glossary/ |title=Mycology Online | Glossary of Mycological Terms |access-date=2013-11-16 |archive-url=https://web.archive.org/web/20131112061336/http://www.mycology.adelaide.edu.au/virtual/glossary/ |archive-date=2013-11-12 |url-status=dead }}</ref> These, in turn, range from solitary to arranged in complex broom-like clusters on fertile hyphae known as conidiophores.<ref name=drfungus/><ref>Fine Structure of Annellophores. I. Scopulariopsis brevicaulis and S. koningii Terrence M. Hammill American Journal of Botany Vol. 58, No. 1 (Jan., 1971), pp. 88-97</ref> The fungus is a typical perithecial member of Phylum Ascomycota, producing minute, enclosed fruiting bodies containing sexual spores (ascospores) in sacs known as asci. The ascospores of ''M. brevicaulis'' are kidney-shaped and reddish-brown in colour.<ref name=drfungus/>
==Ecology== This fungus usually occurs as a mold present in numerous different types of soil as well as various decaying types of organic matter.<ref name=onions1991/><ref>Scopulariopsis brevicaulis in Nails Onsberg, Per DERMATOLOGY, V. 161 (4), 11/1980</ref> ''Microascus brevicaulis'' has a world-wide distribution, and occurs chiefly as a soil saprotroph.<ref name=onions1991/> The species is also encountered with some frequency as a non-dermatophyte agent of nail infections (onychomycosis), particularly in toenails.<ref name=lee2012/><ref name=dehoog2000>{{cite book|last=de Hoog|first=G. S., Guarro J., Gene J., Figueras M.J.|title=Atlas of clinical fungi|year=2000|publisher=Centraalbureau voor Schimmelcultures [u.a.]|location=Utrecht|isbn=978-9070351434|edition=2.}}</ref> Besides the typical soil life of a decomposer, this fungus is also known to live within the American dog tick, ''Dermacentor variabilis''. This relationship seems to be highly adapted but not as a classic host-parasite interaction. Studies have shown ''M. brevicaulis'' inhabits its host as an endosymbiont, and may provides protection against the insect-pathogenic fungus, ''Metarhizium anisopliae''.<ref>An endosymbiotic conidial fungus, Scopulariopsis brevicaulis, protects the American dog tick, ''Dermacentor variabilis'', from desiccation imposed by an entomopathogenic fungus, Journal of Invertebrate Pathology (February 2008), 97 (2), pg. 119-127 J.A. Yoder; J.B. Benoit; D.L. Denlinger; J.L. Tank; L.W. Zettler</ref>
==Pathogenicity in humans== ''Microascus brevicaulis'' has typically been associated with infections located on the skin surface of patients. Though this fungus is responsible for causing several skin related diseases, it is not considered a habitual pathogen.<ref>Plantar Infection by Scopulariopsis brevicaulis Ginarte M. Pereiro Jr. M. Fernández-Redondo V. Toribio J</ref> It is however categorized as a dermatomycotic mold which is known to cause Onychomycosis.<ref name=lee2012/><ref name=dehoog2000/> This is the most prevalent disease affecting human nails but ''M. brevicaulis'' has been isolated from healthy nails as well as diseased ones, indicating that it could be a harmless contaminant in some situations but behave as an opportunistic pathogen in others.<ref>ONYCHOMYCOSIS CAUSED BY SCOPULARIOPSIS BREVICAULIS D. Frey, D. B. Muir 28 JUN 2007</ref>
''Microascus brevicaulis'' is also known to cause granulomatous skin infections in humans.<ref name="bruynzeel">Granulomatous skin infection caused by Scopulariopsis brevicaulis Ineke Bruynzeel, MD, PhD, a and Theo M. Starink, MD, PhDb Amsterdam, the Netherlands</ref> Yet another dermatological disease which may be caused by ''M. brevicaulis'' is skin infection on the sole of the foot.<ref name="ReferenceA">Plantar Infection by Scopulariopsis brevicaulis Ginarte M. Pereiro Jr. M. Fernández-Redondo V. Toribio J</ref> These infections appear as red bumps or (less commonly ridges) around the patients hands and feet. Usually, these infections cause no pain and do not last very long thus resolve without treatment. In some cases however, these types of infection may be persistent and cause great discomfort.<ref name="bruynzeel" />
Yet another dermatological disease which may be caused by ''M. brevicaulis'' is plantar infection.<ref name="ReferenceA" /> This consists of a (potentially thick) scaly plaque that accumulates on the feet. Despite the discomfort and pain which dermatological infections of this sort inflict upon patients, ''M. brevicaulis'' is considerably more dangerous (even fatal) in situations where it manages to bypass the skin and reach deep tissues.<ref>Invasive Scopulariopsis brevicaulis infection in an immunocompromised patient and review of prior cases caused by Scopulariopsis and Microascus species Iwen PC, Schutte SD, Florescu DF, Noel-Hurst RK, Sigler L</ref><ref>Fatal Scopulariopsis brevicaulis infection in a paediatric stem-cell transplant patient treated with voriconazole and caspofungin and a review of Scopulariopsis infections in immunocompromised patients. Steinbach WJ, Schell WA, Miller JL, Perfect JR, Martin P</ref> The danger arises because ''M. brevicaulis'' is a multi-drug resistant, opportunistic pathogen.<ref name="ReferenceB">Scopulariopsis brevicaulis, a Fungal Pathogen Resistant to Broad-Spectrum Antifungal Agents Manuel Cuenca-Estrella, Alicia Gomez-Lopez, Emilia Mellado, Maria J. Buitrago, Araceli Monzón, and Juan L. Rodriguez-Tudela</ref><ref>Disseminated Scopulariopsis brevicaulis infection in an allogeneic stem cell recipient M Vignon, D Michonneau, M-T Baixench, C Al-Nawakil, D Bouscary, A Buzyn, D Salmon and A Paugam</ref> In the past, these kinds of infections mostly occurred if an individual punctured their skin with a stick or experienced some similar form of trauma that could implant ''M. brevicaulis'' below the skin. However, in recent years there has been an increase in the previously rare number of cases of deep tissue infections resulting from ''M. brevicaulis''.<ref>Deep tissue infections caused by Scopulariopsis brevicaulis: report of a case of prosthetic valve endocarditis and review. Migrino RQ, Hall GS, Longworth DL</ref> In contemporary cases where deep tissue invasion has occurred, the patients are almost always immunocompromised. It is believed that the increasing incidence of diseases like AIDS and diabetes coupled with medical practices like chemo-therapy and broad-spectrum antibiotic treatments are primarily responsible for creating a large number of individuals who are predisposed to potentially fatal infections of ''M. brevicaulis''.<ref>Human Hyalohyphomycoses: A Review of Human Infections Due to Acremonium spp., Paecilomyces spp., Penicilliumspp., and Scopulariopsis spp. Schinabeck, M.K.; Ghannoum, M.A.</ref>
Another more recent entry route for this fungus has been an increase in the number of elective surgeries which raise its exposure to internal environments.<ref>Infection with Scopulariopsis brevicaulis after Cosmetic Surgery of the Face. Shin, Myung Geun, Chae, Myong Jong, Oh, Bong Joon, Suh, Soon Pal, Kee, Seung Jung, Cho, Duck, Ryang, Dong Wook, Shin, Jong Hee The Korean Journal of Laboratory Medicine, V. 26 (1), 02/2006, p. 32-35</ref> The occurrence of such infections is on the rise and includes several life-threatening conditions such as: the formation of fungus balls in preformed pulmonary cavities, keratitis, posttraumatic endophthalmitis, disseminated skin lesions in AIDS patients, granulomatous subcutaneous infections, invasive hyalohyphomycosis, pneumonia in leukemic patients, endocarditis related to valvuloplasty or prosthetic valves, and fatal disseminated infection after bone marrow transplantation.<ref name="ReferenceB" /> In other cases, ''M. brevicaulis'' has caused death in immunocompromised patients with hematological diseases.<ref>Disseminated Scopulariopsis brevicaulis infection in an allogeneic stem cell recipient M Vignon, D Michonneau, M-T Baixench, C Al-Nawakil, D Bouscary, A Buzyn, D Salmon and A Paugam</ref>
==References== {{Reflist|30em}}
==External links== * [http://www.speciesfungorum.org/Names/Names.asp Index Fungorum] * [https://web.archive.org/web/20070820101227/http://nt.ars-grin.gov/fungaldatabases/ USDA ARS Fungal Database]
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Category:Microascales Category:Fungal plant pathogens and diseases Category:Fungi described in 1886 Category:Fungus species