ASPERGILLUS

SOIL MICROBIOLOGY

BIOL/CSES 4684


This webpage was created by Caroline Porter


1. IDENTIFYING CHARACTERISTICS

The picture to the left shows A. carbonarious.






2. TAXONOMIC DESCRIPTION


Aspergillus is a saprophytic fungus. It was originally classified as Deuteromycotina, also known as Fungi Imperfecti. Then, after further research, it was reassigned to Ascomycotina because of its ability to form asci within closed ascocarps. This genus has not been subdivided into classes or orders because the classification of the Ascomycetes is not yet complete. There are however, over 200 different species of Aspergillus, some of the more common ones include A. niger, A. flavus, A. utus, A. terreus, A. carbonarious, and A. fumigatus.

The picture to the right is of A. terreus.




3. ISOLATION AND ECOLOGY

Species in the genus Aspergillus are found in various habitats and under many different environmental conditions. Aspergillus is abundant in soil, air, and aquatic settings. Indoors it inhabits areas of high humidity like basements and cellars, it thrives on improperly stored foods, and it can live off duct particles rich in oragnic matter. It has been discovered that this genus is one of the most xerotolerant groups of fungi. Apsrergillus can withstand conditions of low moisture and extreme temperatures. This allows it to act as a 'storage fungi' decaying agricultural products and dried foods.

There are a wide range of applications for Aspergillus species. Some strains are used in producing antibiotics and beneficial genetic mechanisms. Aspergillus is widely used in feed fermentation, allowing the commercial exploitation of many products. A. niger is used to make citric acid, a common preservative in soft drinks, most canned goods, and just about any type of shelf food.

Unfortunately, there are some disadvantages associated with this widespread fungal genus. Aspergillus tends to cause spoilage of foodstuffs and can decompose other materials such as wood, textiles, paint, and leather. Some species will severely damage agricultural crops, for example, A. flavus and A. parasiticus produce aflatoxins that cause ear rot in corn. Another strain, A. fumigatus, releases airborne spores that are potentially pathogenic to humans. If these spores are inhaled during a period when one's immune system is lowered, they will suffer increasingly serious allergies and may eventually contract the disease Aspergillosis.
 

The picture to the left shows a severe case of corn ear rot caused by A. flavus and A. parasiticus.




4. ADDITIONAL SOURCES OF INFORMATION

Bossche, Hugo Vanden, Donald W. R. Mackenzie, and Geert Cauwenbergh. Eds. 1987. Aspergillus and Aspergillosis. Plenum Press. New York, New York. 1-23.

Cole, Gary T. and Robert A. Samson. 1979. Patterns of Development in Conidial Fungi. Pitman. Belmont, California. 58, pp.

Dix, Neville J. and John Webster. 1995. Fungal Ecology. Chapman & Hall. London. 334 -337.

Hawksworth, D. L., P. M. Kirk, B. C. Sutton, and D. N. Pegler. 1995. Ainsworth & Bisby's Dictionary of Fungi. Eighth Edition. CAB Internationsl. Wallingford. 35-38.

Webster, John. 1970. Introduction to Fungi. Cambridge University Press. Cambridge. 202-204.


5. LINKS TO OTHER SITES ON ASPERGILLUS

The Aspergillus Research Page is full of useful information about this particular genus.

To find the ingredients used to make media for A. nidulans cultures visit Aspergillus Medium.

 

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