RESUMO
The maize value chain in the Kogi State and most parts of the country from where maize is purchased into the State lacks mechanisms that ensure grain quality and safety. Against the above-backdrop, this study was designed to evaluate toxigenic fungi and associated mycotoxins in maize produced within different agro-zones of Kogi State. Harvested and stored maize seeds under different storage conditions were collected from three different zones (Zone B Bassa, Zone C Lokoja, and Zone D Idah) and cultured. Different fungal species were isolated by culturing using the spread plate technique on potato dextrose agar (PDA) and identified microscopically. Mycotoxin production by isolated fungi was subsequently evaluated for Deoxynivalenol (DON) contamination using the High-Performance Liquid Chromatography technique (HPLC). The outcome of the study was statistically analysed using simple frequencies and percentages. Aspergillus spp. and Penicillium spp. were the fungi found to be associated with the stored seeds in Kogi, while Fusarium spp. Mucor spp. and Rhizopus spp. were the field fungi identified. Of the thirteen samples collected, the most common genera were Aspergillus (isolated from 41.67% of the evaluated samples), Fusarium (27%) and in a lesser extent Rhizopus spp. (8.33%). The result also shows DON was detected in 92.3% of the stored maize samples, making it one of the widespread mycotoxin contaminants of maize grain. Implications of this study for human and animal health and economic development were discussed and appropriate recommendations made especially for adoption of proper storage technology among small-scale farmers for improved maize quality and safety.
RESUMO
Objective To explore the effects of deoxynivalenol (DON) on apoptosis of human gastric carcinoma cell line SNU in vitro. Methods SNU cells were treated with DON at different concentrations (50, 100, 1000, 2000 μg/L) for 12 hours, and then cells were harvested for cell apoptosis by flow cytometric (FCM) DNA analysis and the expression of Bax, Bcl-2 and Caspase-3 at protein level with FCM and Western blotting. Results FCM results showed that the apoptosis rates of SNU cells in DON treatment groups were all higher than that in control, especially in DON 1000 μg/L and 2000 μg/L groups (P<0.05). In the concentration range from 50 to 2000 μg/L, a significant concentration-depended response correlation could be found between apoptosis rate and DON concentration (r =0.940, P <0.01). FCM and Western blotting showed Bax and Caspase-3 expression in often SNU cells DON treatment for 12 hours were up-regulated while that of Bcl-2 was down-regulated. Conclusion DON can induce apoptosis of SNU cells in vitro in dose-dependent manner, and possible mechanisms of apoptosis induction effects may be up-regulation of the expression of Bax and down-regulation of that of Bcl-2 and activation of the key enzyme of apoptosis Caspase-3.