Malassezia

Malassezia
	Malassezia lipophilis ( SEM image)
Systematics
Sub-kingdom :	Dikarya
Department :	Stand mushrooms (Basidiomycota)
Subdivision :	Ustilaginomycotina
Class :	Malasseziomycetes
Order :	Malasseziales
Genre :	Malassezia
Scientific name of the class
	Malasseziomycetes
	Boekhout , QM Wang & FY Bai
Scientific name of the order
	Malasseziales
	RTMoore
Scientific name of the genus
	Malassezia
	Baill.

Malassezia is a genus of the Malasseziomycetes class and belongs to the smut fungi in the broader sense. Thirteen species are currently recognized. All species are part of the normal skin flora of warm-blooded animal species, including humans, and mostly live on fats. Under certain conditions, they can also become pathogenic .

The genus Malassezia is named after the French physiologist Louis-Charles Malassez (1842–1909).

features

All representatives of the genus Malassezia are zoophilic and, with one exception, Malassezia pachydermatis , lipophilic yeasts. They are found on the skin of domesticated and wild animals, particularly humans, dogs, and cats. In most cases, the skin is colonized, as is the external ear canal.

Malassezia colonies in cultures are small, cream-colored to yellowish, their surface is smooth to weakly wrinkled and dull or shimmering, the edge completely to lobed.

Sexual stages are so far unknown. The yeast stage multiplies asexually through unilateral (unipolar) budding . The daughter cells can also remain connected and form small, sympodially branched systems. The yeast cells are rounded, egg-shaped or cylindrical, and bottle-shaped when they bud. The scar formed by the detachment of the bud is clearly collar-shaped.

The cell wall is thick and consists of several layers that are interlocked due to the invagination of the cell membrane .

Malassezia react positively to staining with Diazonium Blue B , urea is hydrolyzed .

Patient with pityriasis versicolor

Way of life

All species are part of the normal skin flora of warm-blooded animal species, including humans. Malassezia are lipophilic yeasts, so they can extract carbon from fats , the majority of species even depend on fats for their growth. Fermentation does not take place.

pathology

People

Under certain conditions, the species can become pathogens. For humans, Malassezia furfur , the trigger for pityriasis versicolor, plays a particularly important role here . In addition, the infestation can cause seborrhea , folliculitis and systemic infections .

The colonization of the nasal mucosa and the oral cavity can cause chronic rhinosinusitis . The colonization of the lungs is often demonstrated in cystic fibrosis as well as bronchiectasis and in severe cases of bronchial asthma and chronic obstructive pulmonary disease .

A Malassezia -Besiedlung the intestine often extends to the pancreas .
New results show that Malassezia accelerates the growth of certain pancreatic carcinomas .

Animals

In dogs solves Malassezia pachydermatis the dog Malassezia dermatitis from.

Systematics

The genus was in 1889 by Henri Ernest Baillon on the basis of 1853 by Charles-Philippe Robin as Furfur Microsporon first described the type species Malassezia first described. The name honors Louis-Charles Malassez . The order was first described in 1980 by Royall T. Moore .

Through molecular genetic studies it was recognized that the genus Malassezia belongs to the smut fungi in the broader sense, whose species are otherwise all plant pathogens , and here initially to the class of Exobasidiomycetes. The Malasseziales are closely related to the Microstromatales , whose sister taxon they form. A more recent genetic study puts the order of the Malasseziales in a class of its own, the Malasseziomycetes, which in turn only contains the genus Malassezia and is therefore monotypical. Until 1996 only a few species were known, but molecular genetic work by the teams led by Eveline Guého and Takashi Sugita revealed that the morphological appearance of the individual species alone was not a sufficient distinguishing feature and that the previously known species had to be divided into more. The following 13 species are currently recognized in the genus Malassezia:

At times, the species were placed in the genus Pityrosporum , this now synonymous name refers to the associated skin diseases ( pityriasis ).

proof

E. Guého, G. Midgley, J. Guillot: The genus Malassezia with description of four new species In: Antonie van Leeuwenhoek 69, 1996, pp. 337-355

Web links

Commons : Malassezia - collection of images, videos and audio files

Individual evidence

↑ ^a ^b Q.-M. Wang, B. Theelen, M. Groenewald, F.-Y. Bai, T. Boekhout: Moniliellomycetes and Malasseziomycetes, two new classes in Ustilaginomycotina . In: Persoonia - Molecular Phylogeny and Evolution of Fungi . tape 33 , no. 1 , December 10, 2014, p. 41-47 , doi : 10.3767 / 003158514X682313 ( ingenta.com [accessed April 17, 2020]).
↑ Dominik Begerow, Robert Bauer, Teun Boekhout: Phylogenetic placements of ustilaginomycetous anamorphs as deduced from nuclear LSU rDNA sequences . In: Mycological Research . tape 104 , no. 1 , January 2000, p. 53-60 , doi : 10.1017 / S0953756299001161 ( elsevier.com [accessed April 17, 2020]).
↑ ^a ^b ^c ^d ^e ^f ^g Dominik Begerow, Matthias Stoll, Robert Bauer: A phylogenetic hypothesis of Ustilaginomycotina based on multiple gene analyzes and morphological data . In: Mycologia . tape 98 , no. 6 , November 2006, ISSN 0027-5514 , p. 906-916 , doi : 10.1080 / 15572536.2006.11832620 ( tandfonline.com [accessed April 17, 2020]).
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Cvetomir M. Denchev, Royall T. Moore: Validation of Malasseziaceae and Ceraceosoraceae (Exobasidiomycetes) . In: Mycotaxon . tape 110 , no. 1 , December 30, 2009, p. 379–382 , doi : 10.5248 / 110.379 ( ingenta.com [accessed April 17, 2020]).
↑ Peter Reuter: Springer Lexicon Medicine. Springer: Berlin [u. a.] 2004.
↑ http://journal.frontiersin.org/article/10.3389/fmicb.2015.00089/full
^ Fungi accelerate pancreatic cancer. Nature Vol. 574, pp. 184-185 (2019).
↑ The fungal mycobiome promotes pancreatic oncogenesis via activation of MBL. Nature Vol. 574, pp. 264-267 (2019).

[Wang2014-1] Q.-M. Wang, B. Theelen, M. Groenewald, F.-Y. Bai, T. Boekhout: Moniliellomycetes and Malasseziomycetes, two new classes in Ustilaginomycotina . In: Persoonia - Molecular Phylogeny and Evolution of Fungi . tape 33 , no. 1 , December 10, 2014, p. 41-47 , doi : 10.3767 / 003158514X682313 ( ingenta.com [accessed April 17, 2020]).

[2] Dominik Begerow, Robert Bauer, Teun Boekhout: Phylogenetic placements of ustilaginomycetous anamorphs as deduced from nuclear LSU rDNA sequences . In: Mycological Research . tape 104 , no. 1 , January 2000, p. 53-60 , doi : 10.1017 / S0953756299001161 ( elsevier.com [accessed April 17, 2020]).

[:0-3] ↑ ^a ^b ^c ^d ^e ^f ^g Dominik Begerow, Matthias Stoll, Robert Bauer: A phylogenetic hypothesis of Ustilaginomycotina based on multiple gene analyzes and morphological data . In: Mycologia . tape 98 , no. 6 , November 2006, ISSN 0027-5514 , p. 906-916 , doi : 10.1080 / 15572536.2006.11832620 ( tandfonline.com [accessed April 17, 2020]).

[:1-4] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Cvetomir M. Denchev, Royall T. Moore: Validation of Malasseziaceae and Ceraceosoraceae (Exobasidiomycetes) . In: Mycotaxon . tape 110 , no. 1 , December 30, 2009, p. 379–382 , doi : 10.5248 / 110.379 ( ingenta.com [accessed April 17, 2020]).

[5] Peter Reuter: Springer Lexicon Medicine. Springer: Berlin [u. a.] 2004.

[6] ttp://journal.frontiersin.org/article/10.3389/fmicb.2015.00089/full

[7] Fungi accelerate pancreatic cancer. Nature Vol. 574, pp. 184-185 (2019).

[8] The fungal mycobiome promotes pancreatic oncogenesis via activation of MBL. Nature Vol. 574, pp. 264-267 (2019).