Onygenales | |
---|---|
Onygena equina | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Eurotiomycetes |
Subclass: | Eurotiomycetidae |
Order: | Onygenales Cif. ex Benny & Kimbr. (1980) |
Type genus | |
Onygena Pers. (1800) | |
Families | |
Ajellomycetaceae |
The Onygenales are an order of fungi in the class Eurotiomycetes and division Ascomycota. The order's last common ancestor is estimated to have lived 150 million years ago. [1]
Onygenales can consume and break down keratin, the main component of the outer layer of skin. [2] They are primarily found on animals, droppings, and areas frequented by animals. Many are dimorphic, and can change from mold to yeast form depending on their environment. [1]
Many onygenalean fungi are pathogens. [1] One species, Trichophyton rubrum , is the primary cause of athlete's foot. This order also includes Coccidioides implicated in Valley fever. The Onygenales are important as emerging human pathogens because of the rising rates of immunosuppression due to live-organ transplant, HIV/AIDS, and autoimmune disorders such as lupus erythematosus. [3]
Basidiomycota is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basidiomycota includes these groups: agarics, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, chanterelles, earth stars, smuts, bunts, rusts, mirror yeasts, and Cryptococcus, the human pathogenic yeast. Basidiomycota are filamentous fungi composed of hyphae and reproduce sexually via the formation of specialized club-shaped end cells called basidia that normally bear external meiospores. These specialized spores are called basidiospores. However, some Basidiomycota are obligate asexual reproducers. Basidiomycota that reproduce asexually can typically be recognized as members of this division by gross similarity to others, by the formation of a distinctive anatomical feature, cell wall components, and definitively by phylogenetic molecular analysis of DNA sequence data.
Talaromyces marneffei, formerly called Penicillium marneffei, was identified in 1956. The organism is endemic to southeast Asia where it is an important cause of opportunistic infections in those with HIV/AIDS-related immunodeficiency. Incidence of T. marneffei infections has increased due to a rise in HIV infection rates in the region.
Fungal infection, also known as mycosis, is a disease caused by fungi. Different types are traditionally divided according to the part of the body affected; superficial, subcutaneous, and systemic. Superficial fungal infections include common tinea of the skin, such as tinea of the body, groin, hands, feet and beard, and yeast infections such as pityriasis versicolor. Subcutaneous types include eumycetoma and chromoblastomycosis, which generally affect tissues in and beneath the skin. Systemic fungal infections are more serious and include cryptococcosis, histoplasmosis, pneumocystis pneumonia, aspergillosis and mucormycosis. Signs and symptoms range widely. There is usually a rash with superficial infection. Fungal infection within the skin or under the skin may present with a lump and skin changes. Pneumonia-like symptoms or meningitis may occur with a deeper or systemic infection.
Saccharomycotina is a subdivision (subphylum) of the division (phylum) Ascomycota in the kingdom Fungi. It comprises most of the ascomycete yeasts. The members of Saccharomycotina reproduce by budding and they do not produce ascocarps.
Paracoccidioides is a genus of fungi in the order Onygenales. Species are known human pathogens producing yeast-like states under pathogenic conditions. They include the causative agents of paracoccidioidomycosis and lobomycosis.
Histoplasma is a genus of fungi in the order Onygenales. Species are known human pathogens producing yeast-like states under pathogenic conditions. They are the causative agents of histoplasmosis in humans and epizootic lymphangitis in horses.
Habit, equivalent to habitus in some applications in biology, refers variously to aspects of behaviour or structure, as follows:
The Tremellomycetes are a class of dimorphic fungi in the Agaricomycotina. Some species have gelatinous basidiocarps or (microscopically) a sacculate parenthesome. There are six orders, 17 families, and 39 genera in the Tremellomycetes. Tremellomycetes include yeasts, dimorphic taxa, and species that form complex fruiting bodies. Tremellomycetes include some fungi that are human and animal pathogens in the genera Cryptococcus, Naganishia, Papiliotrema, and Trichosporon and some fungi that are cultivated for food in the genera Tremella and Naematelia.
Blastomyces dermatitidis is a dimorphic fungus that causes blastomycosis, an invasive and often serious fungal infection found occasionally in humans and other animals. It lives in soil and wet, decaying wood, often in an area close to a waterway such as a lake, river or stream. Indoor growth may also occur, for example, in accumulated debris in damp sheds or shacks. The fungus is endemic to parts of eastern North America, particularly boreal northern Ontario, southeastern Manitoba, Quebec south of the St. Lawrence River, parts of the U.S. Appalachian mountains and interconnected eastern mountain chains, the west bank of Lake Michigan, the state of Wisconsin, and the entire Mississippi Valley including the valleys of some major tributaries such as the Ohio River. In addition, it occurs rarely in Africa both north and south of the Sahara Desert, as well as in the Arabian Peninsula and the Indian subcontinent. Though it has never been directly observed growing in nature, it is thought to grow there as a cottony white mold, similar to the growth seen in artificial culture at 25 °C (77 °F). In an infected human or animal, however, it converts in growth form and becomes a large-celled budding yeast. Blastomycosis is generally readily treatable with systemic antifungal drugs once it is correctly diagnosed; however, delayed diagnosis is very common except in highly endemic areas.
Lacazia is a genus of fungi containing the single species Lacazia loboi, which is responsible for Lobo's disease. It is a member of the order Onygenales.
Dimorphic fungi are fungi that can exist in the form of both mold and yeast. This is usually brought about by change in temperature and the fungi are also described as thermally dimorphic fungi. An example is Talaromyces marneffei, a human pathogen that grows as a mold at room temperature, and as a yeast at human body temperature.
Pathogenic fungi are fungi that cause disease in humans or other organisms. Although fungi are eukaryotic, many pathogenic fungi are microorganisms. Approximately 300 fungi are known to be pathogenic to humans; their study is called "medical mycology". Fungal infections kill more people than either tuberculosis or malaria—about 2 million people per year.
A fungus 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 one of the traditional eukaryotic kingdoms, along with Animalia, Plantae and either Protista or Protozoa and Chromista.
In biology, a pathogen, in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ.
Blastomyces is a genus of fungi in the order Onygenales. Species are known human pathogens and show thermal dimorphism, converting from hyphal states under saprobic conditions to yeast-like states under pathogenic conditions. They are the causative agents of blastomycosis, a systemic mycosis in immunocompromised patients.
Amauroascus kuehnii is a fungus in the phylum Ascomycota, class Eurotiomycetes. It is keratinophilic but not known to cause any human disease. It has been isolated from animal dungs, soil, and keratinous surfaces of live or deceased animals.
Mucor circinelloides is a dimorphic fungus belonging to the Order Mucorales. It has a worldwide distribution, found mostly in soil, dung and root vegetables. This species is described as not known to be able to produce mycotoxins, however it has been frequently reported to infect animals such as cattle and swine, as well as fowl, platypus and occasionally humans. Ketoacidotic patients are particularly at risk for infection by M. circinelloides.
Uncinocarpus reesii is a species of saprotrophic microfungi that grows in soil and on keratinous materials such as hair, feathers and skin. It was the first species to be designated as part of the genus Uncinocarpus, owing in part to its characteristic development of hooked (uncinate) appendages. As the closest non-pathogenic relative of Coccidioides immitis and C. posadasii, it has become a subject of research interest.
Emmonsiosis, also known as emergomycosis, is a systemic fungal infection that can affect the lungs, generally always affects the skin and can become widespread. The lesions in the skin look like small red bumps and patches with a dip, ulcer and dead tissue in the centre.
Emergomyces is a genus of fungi in the order Onygenales. Species are known human pathogens and show thermal dimorphism, converting from hyphal states under saprobic conditions to yeast-like states under pathogenic conditions. They are the causative agents of emergomycosis, a systemic mycosis in immunocompromised patients. The name Emergomyces refers to these newly emerging mycoses, only encountered in the last few decades.
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