Study on health effect of multiple mycotoxins and their control

真菌的毒性次生代谢物称为真菌毒素。真菌毒素是天然毒素，其发生是食品安全中不可避免的问题。当这些化合物在食物中含量足够高时，它们会对健康产生从急性到慢性的不良影响。在慢性症状中，黄曲霉毒素是典型的致癌物。在黄曲霉毒素的衍生物（B1、B2、G1、G2）中，黄曲霉毒素B1（AFB1）潜力最大。虽然AFB1在食物中受到其他真菌毒素的污染，但关于其他真菌毒素对AFB1致癌活性的影响的信息很少。在本研究中，我们建立了体外和体内评价活性增强AFB1致癌活性的方法。在其他3种黄曲霉毒素（B2、G1、G2）和2种毛霉毒素（T-2毒素和脱氧雪腐镰刀菌醇）中，体外实验发现T-2毒素增强了AFB1的致癌活性。F344雄性大鼠的体内实验也支持这些体外结果。注射T-2毒素后，大鼠T细胞数量减少，B细胞数量增加。NK细胞活性未见改变。乳糜色素P450酶活性显著升高，其中以CYP 3A4、1A2活性最高。与AFB1-DNA加合物相关的活性增加。在控制霉菌毒素产生的土壤细菌的研究中，我们发现了一种抑制霉菌毒素产生的有益细菌——岛青霉黄黄素。经16s DNA序列鉴定，属诺卡菌属。这些结果表明，土壤细菌可以在不改变生态和真菌环境的情况下抑制霉菌毒素的产生。

Toxic secondary metabolites of fungi are called mycotoxins. As mycotoxins are natural toxins, occurrences are unavoidable problem in food safety. When these compounds are present in foods in sufficiently high level, they can have adverse health effects that range from acute to chronic. In chronic symptoms, aflatoxin is typical carcinogen. Among the derivatives of aflatoxins (B1,B2,G1,G2), aflatoxin B1(AFB1) has highest potential. Although AFB1 is contaminated with other mycotoxins in food, there is poor information about the effects of other mycotoxin on carcinogenic activity of AFB1. In this study, we established the assay for evaluation of the activity enhanced AFB1 carcinogenic activity by in vitro and in vivo. Among other three aflatoxins (B2,G1,G2) and two trichothecens mycotoxins (T-2 toxin and deoxynivalenol), in vitro experiment revealed that T-2 toxin enhanced AFB1 carcinogenic activity. In vivo experiment using F344 male rat also supported these in vitro results. In rats administrated with T-2 toxin, T cell population was decreased but B cell population was increased. NK cell activity was not changed. The activities of chytochrome P450 enzyme, especially CYP 3A4, 1A2 were increased. The activity related in the production of AFB1-DNA adduct was increased.In the study on control of soil bacteria for the production of mycotoxins, we found a useful bacterium for inhibition of mycotoxin that is luteoskyrin, production from Penicillium.islandicum. The bacteria were classified in Nocardia species by 16 s DNA sequence identification. These results indicate that the soil bacteria can inhibit production of mycotoxin without changing of ecological and mycological environment.