MRC PhD students

Prof WCA Gelderblom is currently registered for a DSc degree at the Department of Biochemistry, University of Stellenbosch.  Profs P Swart and WFO Marasas are the promoters of the thesis entitled “The fumonsin B mycotoxins: biochemical studies regarding the mechanisms of cancer induction and implications for setting risk assessment parameters in humans”.

The study entails a critical review of the mycotoxicological effects of the fumonisin B (FB) mycotoxins that are natural contaminants of maize and responsible for a variety of diseases in animals.  The role of the fumonisins in human diseases is currently under investigation. Studies that will be reviewed include:

• Investigations on the underlying mechanisms involved in FB-induced carcinogenesis include oxidative damage and the disruption of lipid biosynthesis, with the subsequent alteration of arachidonic acid and ceramide levels that are key determinants in the alteration of growth regulatory responses associated with cancer initiation and promotion.  Studies in normal and liver cancer cell cultures showed that differences exist in the disruption of lipid metabolism, which could be important in the selective stimulation the growth of cancer cells and therefore in the cancer promoting properties of the fumonisins.  
• The study will provide important information on developing chemopreventive strategies for the dietary modulation of the FB1-induced altered growth responses. Interactions with dietary constituents such as iron, aflatoxin B1 and herbal teas will be highlighted.
• The integration of the biological effects of the fumonisins regarding the diverse toxicological effects, level of exposure in humans and the relevant mechanisms involved, will be highlighted in order to establish realistic risk assessment parameters in humans.