Aspergillus fumigatus
| Aspergillus fumigatus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Aspergillus fumigatus | ||||||||||||
| Fresen. |
Aspergillus fumigatus is a fungus from the genus of Aspergillus ( Aspergillus ) in the family of Trichocomaceae . The name comes from the Latin word fumus , meaning smoke, and comes from the smoky green color of the fungus, which is caused by a pigment in the spores .
description
Aspergillus fumigatus grows in velvety, deeply folded or very flaky colonies . The conidiophores are short, smooth and up to 300 micrometers (in extreme cases up to 500 µm) high. They measure 5 to 8 micrometers and increasingly turn green towards the vesicle . The stalks then open into vesicles 20 to 30 micrometers in diameter, the same color as the conidiophores. These are usually only fertile in the upper half.
The sterigmata are in a single, crowded row and measure 6–8 × 2–3 µm. They are also colored green and are more or less axially parallel to the stem. The conidia are spherical or almost spherical with an irregular surface. They measure an average of 2.5-3.0 µm.
Life cycle
The life of an Aspergillus fumigatus begins as a conidia . The conidia are extremely small for mold spores and very resistant to high temperatures, drying out or disinfectants . If there is sufficient water and nutrients in the area, the spores germinate and individual hyphae form . Gradually, the hyphae branch out more and more until a hyphae network forms, which is also known as the mycelium . On the surface of the mycelium, individual conidiophores form , special barrel-shaped heads whose task is to produce new spores. 10,000 new spores are formed per conidiophore and distributed in the room by air turbulence.
Aspergillus fumigatus belongs to the Fungi imperfecti , which means that only the anamorphic is known, which reproduces asexually. The teleomorph is as yet unknown or does not exist. The conidia contain a single haploid nucleus. Since 2005, new scientific findings have now but to sexual reproduction in Aspergillus fumigatus way: By sequencing and analysis of Aspergillus fumigatus - genome were Gene discovered that are specifically necessary for sexual reproduction.
distribution
Aspergillus fumigatus is cosmopolitan . It is one of the most common species on earth, the fungus can be found practically everywhere from Antarctica to the Sahara.
A long-term study from 1963 to 1991 in Cardiff measured an average conidia concentration between 45 and 110 spores per cubic meter of air. The measured maximum concentration was over 100,000 spores in one cubic meter. The concentration is lower in summer than in winter.
Aspergillus fumigatus is a so-called saprophytic fungus that decomposes a large number of substances with its versatile metabolism . It is mainly found on decaying parts of plants. The species is very thermotolerant and can live at temperatures of up to 48 ° C.
Aspergillus fumigatus as a pathogen
Aspergillus fumigatus produces various mycotoxins , especially fumagillin , fumitremorgine , gliotoxin, and sphingofungins . Although the species regularly infects crops and is thus consumed by humans and animals, symptoms of poisoning are either unknown or poorly researched.
Aspergillus fumigatus belongs to the fungi pathogenic to humans and can cause three different groups of diseases:
-
Allergies :
- Here mainly bronchial asthma as a mild form or bronchopulmonary aspergillosis , the so- called farmer's lung, is triggered.
- Infections in people without immunosuppression :
- In particular, people with lung caverns from previous illnesses, but also healthy patients, can develop aspergilloma , a ball of fungus that lodges in the lungs.
- Infections in immunocompromised patients:
- Invasive aspergillosis can occur in immunocompromised patients, especially after bone marrow transplants and in AIDS patients . Invasive aspergillosis is a dangerous infection with a high lethality in the range between 50 and 95%. Here, the inhaled spores are not killed due to the existing immune deficiency and germinate. As a result, hyphae and then mycelium form in the lungs and then spread throughout the body via the bloodstream. The disease becomes particularly dangerous when the fungus reaches the central nervous system . One then speaks of cerebral aspergillosis, this complication is usually fatal.
Aspergillus fumigatus is also disease-causing for animals. Birds (→ aspergillosis of birds ) and dogs (→ sinunasal aspergillosis ) are most frequently affected.
swell
literature
- Kenneth. B. Raper, Dorothy I. Fennel: The Genus Aspergillus . Williams & Wilkins, Baltimore 1965, pp. 142 ff .
- Kyung J. Kwon-Chung, Janyce A. Sugui, Joseph Heitman: Aspergillus fumigatus - What Makes the Species a Ubiquitous Human Fungal Pathogen ?. In: PLoS Pathogens. 9, 2013, p. E1003743, doi: 10.1371 / journal.ppat.1003743 . (Review)
Individual evidence
- ↑ M. Paoletti, C. Rydholm, E. Schwier, M. Anderson, G. Szakacs, F. Lutzoni, J. Debeaupuis, J. Latgé, D. Denning, P. Dyer: Evidence for Sexuality in the Opportunistic Fungal Pathogen Aspergillus fumigatus . In: Current Biology . tape 15 , no. 13 , p. 1242-1248 , doi : 10.1016 / j.cub.2005.05.045 .
- ↑ John Mullins: Aspergillus and Aerobiology . In: Keith A. Owell, Annabel Renwick, John F. Pederby (Eds.): The Genus Aspergillus . Plenum Press, New York 1994, ISBN 0-306-44701-0 , pp. 351-359 .
- ↑ R. Bhabhra, DS Askew: Thermotolerance and virulence of Aspergillus fumigatus: role of the fungal nucleolus . In: Medical Mycology Supplement 1 . tape 43 , 2005, p. 87-93 , doi : 10.1080 / 13693780400029486 , PMID 16110798 ( oxfordjournals.org [PDF; 244 kB ]). PDF; 244kB ( Memento of the original from February 20, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Maurice O. Moss: Biosynthesis of Aspergillus Toxins - Non Aflatoxins . In: Keith A. Owell, Annabel Renwick, John F. Pederby (Eds.): The Genus Aspergillus . Plenum Press, New York 1994, ISBN 0-306-44701-0 , pp. 29-50 .
- ↑ Keith A. Scudamore: Aspergillus Toxins in Food and Animal Feedindstuff . In: Keith A. Owell, Annabel Renwick, John F. Pederby (Eds.): The Genus Aspergillus . Plenum Press, New York 1994, ISBN 0-306-44701-0 , pp. 59-71 .
- ^ Raper et Fennel, p. 82ff
Web links
- Pathophysiology of Aspergillus fumigatus. Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, accessed on February 14, 2010 .
