Chaetomium globosum and Fusarium oxysporum

obmar · Chaetomium globosum and Fusarium oxysporum

The changes in sugar, ascorbic acid, phenol and protein contents of A. malaccensis were investigated after inoculation with Chaetomium globosum and Fusarium oxysporum. In healthy trees, the biochemical constituents increased. In infected trees, a decrease in the biochemical constituents was observed after inoculation with the fungi.

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http://www.broad.mit.edu/annotati...ome/chaetomium_globosum/Home.html

What is Chaetomium globosum?
Chaetomium is a genus of filamentous fungi (Phylum Ascomycota, Class Sordariomycetes) encompassing species that typically possess densely setose, ovoid to pyriform ostiolate ascomata, clavate asci and pigmented, one-celled ascospores (Domsch et al. 1993). Species of Chaetomium are important in the decomposition of plant and other cellulose-rich materials, and can be isolated easily from dung, plant debris and soil. The genus contains a number of species capable of growth at elevated temperatures as well as a few species that cause infections in vertebrates. Chaetomium globosum, the type species of the genus, can be isolated easily from decaying plant material, seeds and other cellulosic substrates. It is the most frequently isolated and cosmopolitan of the over 150 species of Chaetomium described to date (Domsch et al. 1993).

Chaetomium globosum is a medically important fungus and is encountered typically as an agent of skin and nail infections in humans. This species more rarely causes cerebral and systemic infections, but such mycoses have high mortality rates, particularly in immunocompromised patients (Serena et al. 2003). Chaetomium globosum is important to human health as a contaminant in indoor environments since it is known to produce mycotoxins (Nielsen et al. 1999; Pieckova 2003) and act as an allergen.

References

Domsch, K.H. et al. (1999). Compendium of soil fungi. Volume 1. Academic Press, London, UK.
Nielsen, K.F. et al. (1999). Production of mycotoxins on artificially and naturally infested building materials. Mycopathologia 145(1):43-56.
Pieckova, E. (2003). In vitro toxicity of indoor Chaetomium Kunze ex Fr. Ann. Agric. Environ. Med. 10(1):9-14.
Serena, C. et al. (2003). In vitro activities of new antifungal agents against Chaetomium spp. and inoculum standardization. Antimicrob. Agents Chemother. 47(10):3161-3164.

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http://www.doctorfungus.org/thefungi/Fusarium_oxysporum.htm

Macroscopic morphology

Macroscopic morphology may vary significantly on different media, and descriptions here are based upon growth on potato flakes agar at 25°C with on/off fluorescent light cycles of approximately 12 hours each. Rapid growth. Colonies are initially white, becoming tinged with salmon and lavender at maturity. Lavender to purple reverse. Salmon to orange sporodochia may be present [2202], [1630].

Microscopic morphology

Hyphae are septate and hyaline. Conidiophores are short (when contrasted with those of F. solani) and simple (usually not branched). Macroconidia usually produced abundantly, slightly sickle-shaped, thin-walled, with an attenuated apical cell and a foot-shaped basal cell. They are three to 5-septate measuring 23-54 x 3-4.5 µm. Microconidia are abundant, mostly non-septate, ellipsoidal to cylindrical, slightly curved or straight, 5-12 x 2.3-3.5 µm occurring in false heads (a collection of conidia at the tip of the phialide) from short monophialides. Chlamydoconidia are present and often abundant, occurring singly and in pairs [2202], [1630].

Special notes

While F. solani is the most common clinical isolate, Fusarium oxysporum appears to be the second most common species recovered [69]. It has been reported in skin and nail infections [1961], in subcutaneous disease [140], in a neutropenic child managed with granulocyte colony-stimulating factor [1025], in a disseminated infection in hemophagocytic lymphohistiocytosis [43], and in a fatal case involving a cross reaction with a pan-Candida genus probe. O'Donnell et al. reported it to be a genetically diverse human pathogenic species best described as a Fusarium oxysporum species complex. Concordant results from phylogenetic analysis of multilocus DNA sequence data and amplified fragment length polymorphisms showed that a geographically widespread clonal lineage comprised greater than 70% of all clinical isolates investigated, including strains investigated from a pseudoepidemic involving bronchial lavage isolates in a San Antonio hospital, and from water systems in hospitals in Houston, Baltimore, and Seattle [1666]. The species is usually easily identified by its lavender color on potato dextrose agar, its short monophialides, and microconidia formed only in false heads.