Reduction of methionine based sulfur-containing carcinogen using halotolerant yeast cells

使用耐盐酵母细胞减少基于蛋氨酸的含硫致癌物

• 批准号: 11680151
• 负责人: ISHIHARA Kazuo
• 金额: $ 2.37万
• 依托单位: Niigata Women's College
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680151/
• 关键词: methionine; carcinogen; sulfur-containing compound; halotolerant yeast; Zygosaccharomyces rouxii; Saccharomyces cerevisiae; Zygosaccharomyces rouxii

J.H.Weisburger, et al.^<1)> isolated a compound, 2-chloro-4-methylthiobutanoic acid (CMBA), capable of inducing gastric cancer from a salted Pacific saury, which is a Japanese processed marine product. CMBA is produced in the presence of methionine, sodium nitrite and sodium chloride, which are used as food additives.In this study, we attempted to reduce the amount of CMBA produced using a halotolerant yeast isolated from a soybean paste. For analyzing the amount of CMBA, we performed a mutagenicity test using Salmonella tryphimurium TA100, histidine auxotrophic mutant of Salmonella or Ames test. The number of reverse mutation colonies decreased depending on the amount of concentrated extract of Zygosaccharomyces rouxii S-2B (halotolerant yeast) was added, and about 30% reduction was observed when 30μl (equivalent to〜1.2×10^7bacteria) of the concentrated extract was added to 50 gg of CMBA.In addition, the inhibitory effects of the yeast cells toward CMBA were determined by culturing. Zygosaccharomyces rouxii S96, a halotolerant yeast, and Saccharomyces cerevisiae RIB6002 (Kyokai No.7) of sake yeast, a non-halotolerant yeast, were used as test strains. Both the strains were cultured with CMBA for 0, 0.5, 3, and 24h. As a result, both strains were found to decrease the amount of CMBA present in the culture with increase in contact time. The reduction rates after 24 h of contact time were 29.7% for Z.rouxii S96 and 14.2% for S.cerevisiae in 24h of contact time. This reduction was probably because CMBA was found to be adsorbed on the positively charged surface of yeast cells. Based on these results, we conclude that CMBA, which is known to cause gastric cancer, can effectively be reduced using halotolerant yeast cells.1) Wei Chen, John H.Weisburger, et. al. : NATURE, 374, 599 (1995)

J.H.Weisburger，et al.^&lt；1)&GT；从一种日本加工的太平洋秋刀鱼中分离出一种化合物，2-氯-4-甲硫代丁酸(CMBA)，能够诱发胃癌。CMBA是在蛋氨酸、亚硝酸钠和氯化钠作为食品添加剂的情况下产生的。在这项研究中，我们试图减少从大豆酱中分离的耐盐酵母产生CMBA的量。为了分析CMBA的含量，我们对沙门氏菌的组氨酸营养缺陷型突变株TA100进行了诱变试验或Ames试验。突变菌落数随鲁氏酵母S-2B(耐盐酵母)浓度的增加而减少，在50gCMBA中加入30μL(相当于1·2×10~(-7)个细菌)时，突变菌落数减少约30%。以耐盐酵母鲁氏酵母S96和非耐盐酵母酿酒酵母RIB6002(京开7号)为试验菌株。用CMBA分别培养0、0.5、3、24小时。结果发现，两个菌株都随着接触时间的增加而减少了培养物中CMBA的含量。鲁氏酵母S96和酿酒酵母作用24 h的减少率分别为29.7%和14.2%。这可能是因为CMBA被吸附在酵母细胞带正电的表面。基于这些结果，我们得出结论，使用耐盐酵母细胞可以有效地减少已知的导致胃癌的CMBA。艾尔《自然》，374,599(1995)