Tuesday, 12 February 2019

Toxins of Fungus

Toxins of Fungus

Claviceps Toxins

Claviceps Toxins

Ergot alkaloids have come in sclerotia of Claviceps, which are produced on cereals, especially in whole rye. These are sclerotia that are often removed before milling of the rye, and outbreaks of ergotism rarely occur now.

Major sources. Claviceps purpurea and C. Paspali are the major sources of the ergot alkaloids (Blum, 1995). Several Penicillium and Aspergilli can produce clavinet type alkaloids also, but their possible role in mycotoxicology is unknown.

Alternaria Toxins

Alternaria Toxins

Tenuazonic acid regarded as the most toxic of the secondary metabolites from Alternaria (Blaney, 1991). It is also produced by a Phoma species.

Major sources. Phoma sorghum appears to be the most important producer of tenuazonic acid. It has been associated with onyalai, a hematological disease (Steyn and Rabie, 1976). Species are the Alternaria Tenuissima complex often produces tenuazonic acid, but it has not been found in isolates of A. Alternate Sensu Stricto. A. Citri, A. japonica, A. Kikuchiana, A. longipes, A. mali, A. Oryzae, and A. Solani have been also reported to produce Tenuazonic acid (Sivanesan, 1991).

Metabolites have found in Alternaria, and some can occur naturally in tomatoes, apples and other fruits (Sivanesan, 1991; Andersen and Frisvad, 2004). The toxicity of such compounds, including alternatives, is not well examined.

Phoma and Phomopsis Toxins

Phomopsis Toxins

Lupinosis toxin (Phomopsin) is produced when Phomopsis Leptostromiformis grows on lupin plants (Lupinus species) and lupin seeds (Culvenor et al., 1977). It is a hepatotoxin that has caused widespread disease in sheep grazing lupins in Australia, South Africa and parts of Europe (Marasas, 1974; Culvenor et al., 1977). As lupin seed is used to human food in South Asia, quality control of Phomopsin is important.

Pithomyces Toxins

Sporidesmin is produced by Pithomyces Chartarum and the causes of facial eczema in sheep (Atherton et al., 1974). However, this is a disease of pasture only.

Stachybotrys Toxins

Stachybotrys and Memnoniella spp. primary of the importance of indoor air, but Stachybotrytoxicosis was one of the first equine mycotoxicosis to be reported (Rodrick and Eppley, 1974). Stachybotrys Chartarum and S. Chlorohalonata are the two important fungi producing by cyclic trichothecenes (Aatratoxins) and toxic Atranones (Andersen et al., 2003; Jarvis, 2003).

Monascus Toxins

Monascus rubber is used in the production of red rice in the Orient and is a source of red food coloring. However, it has been repeatedly reported to produce citrinin (Blanc et al., 1995).

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