Mechanisms fumonisins

Constable, P. D., Smith, G. W., Rottinghaus, G. E., and Haschek, W. M. (2000). Ingestion of fumonisin Bl-containing culture material decreases cardiac contractility and mechanical efficiency in swine. Toxicol. Appl. Pharmacol. 162(3), 151-160. 

Gelineau-van Waes, J., Starr, L., Maddox, J., Aleman, F., Voss, K. A., Wilberding, J., and Riley, R. T. (2005). Maternal fumonisin exposure and risk for neural tube defects Mechanisms in an in vivo mouse model. Birth Defects Res. A Clin. Mol. Teratol. 73(7), 487-497. 

Proctor RH Fusarium toxins Trichothecenes and Fumonisins in Cary JW, Linz JE, Bhatnagar D (eds) Microbial Foodbome Diseases Mechanism of pathogenesis and toxin synthesis. Lancaster, Technomic Publishing 2000, pp 363—381. 

Soriano JM, Gonzalez L, Catala AI. Mechanism of action of sphingolipids and their metabolites in the toxicity of fumonisin Bl. Prog. Lipid Res. 2005 44 345-356. 

In spite of the importance of fumonisins, detailed molecular mechanism for their biosynthesis has just started to emerge in recent years. An understanding of the molecular mechanism is critical to the development of rational approaches to mycotoxin elimination in agriculture and food industry. This review intends to highlight the process in this area. 

The biosynthetic origin of fumonisins has been studied by several groups. C-3 to C-20 of the carbon backbone are derived fi om acetate, and C-1 and C-2, as well as the C-2 amino, are derived fi om alanine (17, 19). The two methyl groups at C-12 and C-16 are derived fi om methionine (20). Therefore, the biosynthesis of the carbon backbone of fumonisins is likely to involve a polyketide mechanism (27). The origin of the hydroxyl on the carbon backbone has also... 

Based on the paradigm of NRPS-catalyzed reactions, we proposed a mechanism for the biosynthesis of the tricarballylic esters of fumonisins (Figure 5). The first step is the ATP-dependent activation of a tricarboxylate substrate by FumlOp to form an acyl-AMP, which is subsequently transferred to the PCP domain of Fuml4p. The exact substrate for FumlOp is not known, but is likely to be an intermediate of the tricaroxylatic acid cycle 17). The data obtained from the FUM7 deletion mutant suggested that the substrate of FumlOp could be a... 

There is ample evidence for hydroxy fatty acids in other yeasts. Saccharomycopsis malanga (Ascomycota, Saccharomycetales, Saccharomyco-psidaceae) forms 3-hydroxypalmitic acid [31] while trihydroxy acids are formed in Picia sydowiorum (Ascomycota, Saccharomycetales, Saccharomycetaceae) [32] and an unidentified yeast [33]. 2-Hydroxy long-chain fatty acids are found in S. cerevisiae [34]. The production of 2-hydroxyhexadecanoic acid in P. sydowiorum was increased in the presence of the mycotoxin fumonisin B, and a cyt P-450 mechanism of production suggested [32]. In many cases, these compounds are esterified in wall or membrane fractions but they may also occur as free acids. Unfortunately, none of these oxylipins has been linked to a specific regulatory function. 

C. I Mechanism of toxicologic ilam e. Fumonisins inhibit the enzyme-mediated conversion... 

The fumonisins have been associated with human cancer (32, 77), although the mechanism of carcinogenicity is unknown. FBi was not found to be mutagenic in the Salmonella mutagenicity assay and was not genotoxic in DNA repair assays (65). The fumonisins appear to act mainly as tumor promoters. 

Schroeder, J.J., Crane, H.M., Xia, J., Liotta, D.C., and Merrill, A.H.,Jr., 1994, Dismption of sphingolipid metabolism and stimulation of DNA synthesis by fumonisin B1. A molecular mechanism for carcinogenesis assosiated with Fusarium moniliforme, J.Biol.Chem. 269(5) 3475-3481. 

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