Student Research: Kathleen M. Bradley

, Environmental Toxicology (Tox), 2004
Faculty Advisor: David L. Eaton

Effects of Phytochemicals on AFB1-mediated Genotoxicity in HepG2 Cells


Abstract

It was not until the early 1960's with the outbreak of Turkey X disease that aflatoxins were discovered (Asplin 1961, Blount 1961). Aflatoxins are a group of difurancoumarin compounds that includes Aflatoxins B1, B2, G1, and G2. They are produced as secondary metabolites by the common fungal molds, Aspergillus flavus and Aspergillus parasiticus. These molds thrive on host crops such as corn and peanuts under optimal growth conditions that include high heat and humidity (Wilson 1994). However, they have been retrospectively identified as the casual agent in non-infectious acute heptotoxic disease in animals as early as the 1940's and 1950's (Paget 1954, Schoental 1961). With the outbreak of turkey X disease, over 100,000 turkeys were infected with acute hepatotoxicity. Subsequently the source was identified as a contaminated peanut meal that served as animal feed. The contaminant was a mold that produced highly fluorescent compounds, and was eventually isolated and identified in 1963 as four closely-related mycotoxins named aflatoxin B1 (AFB1), B2 (AFB2), G1(AFG1), and G2 (AFG2 ) (Hartley 1963, Asao 1963). Subsequently, in 1965 the compounds' structural charcterization was determined (Buchi 1974). The outbreak of turkey X disease preceeded an outbreak of hepatocellular carcinomas in hatchery-reared rainbow trout that were inadvertently fed an aflatoxin-contaminated feed (Halver 1969).

Taken from the beginning of thesis.