Toxicological Study of Fusarium moniliforme

本项目对念珠镰刀菌进行了一系列毒理学研究。对不同农产品中念珠菌及其相关菌种的污染进行了研究。进口的美国玉米被念珠菌严重污染。除念珠状镰刀菌外，主要从大麦和小麦中分离到镰刀菌，10份小麦样品中仅分离到1份念珠状镰刀菌。从中国和泰国进口的部分薏米样品中检出念珠菌。镰刀菌在土壤中的分布研究表明，只有甘蔗农田土壤中存在念珠状镰刀菌和亚粘滞镰刀菌。建立了富马菌素的分析方法。富马菌素是念珠菌产生的毒素之一。用这种方法测定了美国玉米中的毒素浓度，结果显示污染严重。该方法也使我们能够研究从国内农产品和土壤中分离的念珠菌和念珠菌变种的产毒作用。一些菌株对伏马菌素B1和B2.3的生产能力非常高。采用多种哺乳动物培养细胞、原代培养细胞和实验动物对本项目分离得到的念珠菌提取物及其柱状组分的毒性进行了研究。结果表明可能存在一种新的毒素。在细胞水平上对伏马菌素毒性作用的生化研究表明，伏马菌素通过抑制鞘氨酸和鞘氨酸n -乙酰转移酶活性来抑制鞘脂的生物合成。

A series of toxicological studies of Fusarium moniliforme was conducted in this project.1. Contamination of various agricultural products with F. moniliforme and relating species was studied. Imported US corn was heavily contaminated with F. moniliforme. Mainly Fusarium species other than F. moniliforme were isolated from domestic barley and wheat : F. moniliforme was isolated only from one out of 10 wheat samples. A few of pearl barley samples imported from China and Thailand were contaminated with F. moniliforme.Study of distribution of Fusarium species in soil showed the presence of F. moniliforme and F. subglutinans only in soil of sugarcane farm.2. Method of analysis of fumonisin, one of the toxins produced by F. moniliforme, was developed and established. Determination of the toxin concentration in the US corn with this method revealed heavy contamination. This method also enabled us to study the toxin production by the strains of the F. moniliforme and F. moniliforme var. subgluticans isolated from domestic agricultural products and soil. Several strains showed very high producibility of fumonisin B1 and B2.3. Toxicity of cultural extracts and their column fractions of F. moniliforme isolated in this project was examined by using various mammalian cultured cells, primary cultured cees and experimental animals. The result suggested possible presence of a new toxin.4. Biochemical study of toxic effects of fumonisin at the cellular level demonstrated that the toxin inhibited the sphingolipid biosynthesis through inhibition of sphingosine and sphinganine N-acetyltransferase activity.