Research And Applications Of Gene Chip On Detecting Genes Involved In Aflatoxin Biosynthesis

Aflatoxin is one of the most popular mycotoxin. They are widely found in soil, animals and plants, especially in tranditional crops such as peanut and maize. They are catagarized as sort I carcinogen by World Health Organization because they have deleterious seriously effects on liver of people and animals and can lead to hepatic cancer and even to death.The methodology of Plackett-Burman(PB) was undertaken to screen the significant growth factors having effects on production of aflatxoin. The effects which the key factors have on production of aflatxoin of Aspergillus parasiticus AS3.4407 and Aspergillus flavus AS3.4409 were researched using Respond Surface Methodology(RSM) in this article as well as interaction among the key factors. Corresponding condictions under which the production of aflatoxin is minimum and maximum, were abtained. It is impontant and necessary to aflatoxin contamination control on crops. At the same time, the technology of gene chip was used in the analysis of genes involved in aflatoxin biosynthesis as well as RT-PCR method. Six genes which expressed differently were abtained. The relationship between differently expressed genes and aflatoxin production was researched in this article. It provides a effective technique to screen genes involved in citrinin biosynthisis of Monascus aurantiacus. The main results are as follows:1 HPLC-flurescence detection method to determination aflatoxin was developed. The elute was detected by HPLC with fluorescence detector. Samples were extracted with triple chloraform (v/v). The final extract was then derivatized with iodine liquor. HPLC equiped with reverse C₁₈ column (250×4.6mm) was used. Mobile phase is methanol:acetronile: water (30:20:50, v/v/v) and the speed of flowing is 0.8 mL/min. The limit of detection (FLD) of method was 2 ng/mL for AFB₁. Recoveries of AFB₁ spiked at levels of 6.25-1000 ng/mL ranged from 86.4-96.8% for fermented liquor, with coefficients of variation(CVs) less than 7.0%. The AFB₁ extraction of sample can be detected without being purified. And AFB₁ can be seperated with AFB₂,...