Guelph Food Research Centre, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada.
BMC Microbiol. 2010 Jun 24;10:182. doi: 10.1186/1471-2180-10-182.
Contamination of grains with trichothecene mycotoxins, especially deoxynivalenol (DON), has been an ongoing problem for Canada and many other countries. Mycotoxin contamination creates food safety risks, reduces grain market values, threatens livestock industries, and limits agricultural produce exports. DON is a secondary metabolite produced by some Fusarium species of fungi. To date, there is a lack of effective and economical methods to significantly reduce the levels of trichothecene mycotoxins in food and feed, including the efforts to breed Fusarium pathogen-resistant crops and chemical/physical treatments to remove the mycotoxins. Biological approaches, such as the use of microorganisms to convert the toxins to non- or less toxic compounds, have become a preferred choice recently due to their high specificity, efficacy, and environmental soundness. However, such approaches are often limited by the availability of microbial agents with the ability to detoxify the mycotoxins. In the present study, an approach with PCR-DGGE guided microbial selection was developed and used to isolate DON -transforming bacteria from chicken intestines, which resulted in the successful isolation of several bacterial isolates that demonstrated the function to transform DON to its de-epoxy form, deepoxy-4-deoxynivalenol (DOM-1), a product much less toxic than DON.
The use of conventional microbiological selection strategies guided by PCR-DGGE (denaturing gradient gel electrophoresis) bacterial profiles for isolating DON-transforming bacteria has significantly increased the efficiency of the bacterial selection. Ten isolates were identified and isolated from chicken intestines. They were all able to transform DON to DOM-1. Most isolates were potent in transforming DON and the activity was stable during subculturing. Sequence data of partial 16S rRNA genes indicate that the ten isolates belong to four different bacterial groups, Clostridiales, Anaerofilum, Collinsella, and Bacillus.
The approach with PCR-DGGE guided microbial selection was effective in isolating DON-transforming bacteria and the obtained bacterial isolates were able to transform DON.
真菌毒素，尤其是脱氧雪腐镰刀菌烯醇（DON），对加拿大和许多其他国家的谷物造成了持续的污染。真菌毒素污染带来了食品安全风险，降低了谷物市场价值，威胁了畜牧业的发展，并限制了农产品出口。DON 是某些镰刀菌真菌产生的次生代谢物。迄今为止，还缺乏有效且经济的方法来显著降低食品和饲料中真菌毒素的水平，包括培育镰刀菌病原体抗性作物和化学/物理处理以去除真菌毒素。生物方法，如利用微生物将毒素转化为非毒性或毒性较小的化合物，由于其特异性高、效果好且环境友好，最近已成为首选方法。然而，由于缺乏具有解毒真菌毒素能力的微生物制剂，此类方法往往受到限制。在本研究中，开发了一种基于 PCR-DGGE 指导的微生物选择方法，并用于从鸡肠中分离 DON 转化细菌，成功分离出了几种能够将 DON 转化为其去环氧形式（DOM-1）的细菌，DOM-1 的毒性远低于 DON。
使用基于 PCR-DGGE（变性梯度凝胶电泳）细菌图谱的常规微生物选择策略来分离 DON 转化细菌，显著提高了细菌选择的效率。从鸡肠中分离出 10 个能够将 DON 转化为 DOM-1 的分离物。它们都能够将 DON 转化为 DOM-1。大多数分离物具有很强的 DON 转化能力，并且在传代过程中活性稳定。部分 16S rRNA 基因序列数据表明，这 10 个分离物属于四个不同的细菌群，分别是梭菌目、厌氧真杆菌属、柯林斯氏菌属和芽孢杆菌属。
基于 PCR-DGGE 指导的微生物选择方法有效分离了 DON 转化细菌，所获得的细菌分离物能够转化 DON。
