Fungi, toxicity

Aryl-3-arylimino[l,2,4]triazolo[3,4-c][l,2,4]dithiazoles 138 have been compared with dithane M-45 for their fungi-toxicity against Helmintosporium oryzae and Fusarium oxysporium <1983ABC1017>. 

The 3-deoxyanthocyanidins are a class of phytoalexins found in sorghum. These compounds are so fungi-toxic that they are effective at femtogram levels (Snyder and Nicholson, 1990 Nicholson and Wood, 2001). The synthesis of these compounds is initiated on the endoplasmic reticulum. Compounds are then trafficked in subcellular inclusions. The inclusions appear similar to vesicles, but there is no evidence that membranes surround the inclusions (Snyder and Nicholson, 1990). Nielsen et al. (2004) recently summarized this defense response. The cytological response commences when clear, colorless inclusions (less than 0.1 pm in diameter) accumulate in leaf cells under fungal attack. The inclusions eventually are seen as red bodies at the infection site. When the 3-deoxyanthocyanidins enter the apoplast, the host cell collapses. The phytoalexins then accumulate in the pathogen and cause its death. Excess phytoalexins are trapped in host cell walls at infection sites (Lo et al., 1998 1999). 

Little is known about the mode of action of hydra-zinecarboxamide-derived fungicides. Since diazene formation is involved in the fungitoxic action of phenyl-thiosemicarbazide (2 2) and is implicated in a glutathione-oxidation mechanism to account for fungi-toxicity of similarly structured compounds (2 1 ), it is conceivable that diazenes described in this study may well play a critical role in the action of fluorine-substituted hydrazinecarboxamide fungicides and perhaps larvicides as well. 

Biological pollutant are due to fungi toxic metabolites which can contaminate foods are known as micotoxins. These products are not necessary for the fungi growth and they can be present in the enviromnent as well as in foods. Their effect on the human health depend not only by its characteristic, but also by the immune system of each person. A biosensor system is developed in order to evaluate contaminants in very simple and quick way. The results are compared with standard methods such as HPLC and ELISA. 

The isoflavones luteone (86) and wighteone (87) occur on the leaf surfaces of Lupinus species and appear to be preformed antifungal defenses both compounds are fungi-toxic to Helminthosporium carbonum (Harbome, 1986, 1991). 

Clemons, G. P. Sisler, H. B. (1971). Localization of the site of action of a fungi-toxic benomyl derivative. Pestic. Biochem. Biophys, 1, 32-43. 

Rudman P 1963 The causes of natural durability in timber. XI. Some tests on the fungi toxicity of wood extractives and related compounds. Holzforschung 17 54-57... 

Benzothiazolium salts have great use in the synthesis of different types of cyanine dyes while on the other hand the benzothiazolium salts have also been studied for their activity in different biological systems. In 1959 Pianka and Hall studied the fungi toxicity of 3-ethylbenzothiazolium iodide and 3-ethylbenzoxazolium ethyl sulfate derivatives and activity was found to reside only in the cation (Pianka Hall 1959). In the same year (1959) Leslie and co-workers patented a method for the preparation of quaternary salts of benzothiazole for making the thiacarbocyanine dyes. In 1961 Horwitz and co-workers prepared a benzothiazolium salt (76) from 6-(2-aminocarbonyl)ethoxy-2-methylbenzothiazole (75, Scheme-22) for the use in preparation of different dyes. 

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