霉变食品中新亚硝胺:N-3-甲基丁基-N-1-甲基丙酮基亚硝胺

以林县粮食中常见的霉菌如白地霉、土曲霉等接种于玉米面饼上,培养数日后,加一定量亚硝酸钠,即可产生亚硝胺,其中经高分辨GC-MS证实,有N-3-甲基丁基-N-1-甲基丙酮基亚硝胺,我们又通过化学合成MAMBNA加以验证,证明化学合成的MAMBNA与霉变玉米面饼中分离的MAMBNA结构完全一致,本文对产生这种新亚硝胺的物质基础和其在食管癌高发区中的意义进行了讨论。     

致癌的亚硝胺在霉变玉米面中的形成

以林县粮食中常见的霉菌,如串珠镰刀菌、黄曲霉菌等,接种于玉米面饼,培养数日后,加一定量的亚硝酸钠,其提取物经GC-MS证实能产生DMNA,DENA与MBNA,这些致癌亚硝胺化合物能诱发动物的肝癌或食管癌.在霉变食物中,霉菌除产生毒素外,还能促进化学致癌物的形成,这为肿瘤病因学提供了新的研究领域。     

A NEW N-NITROSO COMPOUND, N-2-METHYLPROPYL-N-1-METHYLACE-TONYL-NITROSAMINE, IN MOLDY MILLET AND WHEAT FLOUR

A new N-nitroso compound, N-2-methylpropyl-N-1-methylacetonyl-nitrosamine(MAMPNA), was found in millet and wheat flour inoculated with Fusarium moniliformeSheldon, a common species of fungi occurring in foods in Linxian County, after 8-day incu-bation and an addition of a small amount of NaNO_2. The compound has been identified byGC-MS and confirmed by synthesized MAMPNA. The present paper reports the isolationand detection of MAMPNA in moldy foods, and discusses the role of the fungus in processesof nitrosamine formation and possible biosynthetic approach of the new compound.     

SYNTHESIS OF METHYLISOAMYLNITROSAMINE FROM ISOAMYLAMINE BY FUNGI(FUSARIUM MONILIFORME)

Methylisoamylnitrosamine, a carcinogenic N-nitroso compound, has been formed in glucose ammonium nitrate medium containing 150 mg of isoamylamine (a primary amine) inoculated with a common fungus (Fusarium moniliforme Sheldon), to which 400 mg NaNO_2 are added after incubation for 7—8 days at 28℃. No such compound has been found in control samples without fungi or isoamylamine. This paper reports a method of experimental synthesis of the nitrosamine by F. moniliforme strains 82—01 and 83—01, using isoamylamine and NaNO_2, as well as the analysis of the compound by GC/MS and GC/TEA.     

N-3-甲基丁基-N-1-甲基丙酮基亚硝胺体外恶性转化金仓鼠肺成纤维细胞的研究

一种存在于林县霉变玉米面中的新亚硝胺化合物——N-3-甲基丁基-N-1-甲基丙酮基亚硝胺(MAMBNA)已人工合成。利用新生金仓鼠肺成纤维细胞体外恶性转化模型,引入微粒体酶代谢激活系统检测了MAMBNA。实验结果,MAMBNA同已知的强化学致癌物N-甲基-N'-硝基-N-亚硝基胍和二乙基亚硝胺一样,能使体外培养的金仓鼠肺成纤维细胞发生恶性转化。证明MAMBNA是林县这一高癌地区的一种环境致癌物。本系统除可用于检测可疑环境致癌物外,尚可作为研究癌变机理的体外模型。     

霉变小米和面粉中的一种新亚硝基化合物:N-2-甲基丙基-N-1-甲基丙酮基亚硝胺

以林县食物中常见的串珠镰刀菌接种于小米和面粉,培养数日后加少量亚硝酸钠,可得一种新的亚硝基化合物:N-2-甲基丙基-N-1-甲基丙酮基亚硝胺(N-2-me-thylpropyl-N-1-methylacetonylnitrosamine,简称MAMPNA).这种化合物已用GC/MS鉴定,并经合成的MAMPNA证实.本文报道 MAMPNA的分离和鉴定,并对霉菌在亚硝胺生成中的作用及这种新亚硝基化合物生物合成的可能途径进行了讨论。     

串珠镰刀菌利用异戊胺合成甲基异戊基亚硝胺

接种串珠镰刀菌于葡萄糖硝酸铵培养基中,加150mg异戊胺,28℃培养7—8天后,再加入400mg NaNO_2可以形成甲基异戊基亚硝胺。不接种霉菌,或不加异戊胺的对照瓶均无该种亚硝胺的生成。本文报告串珠镰刀菌(82-01号和83-01号)利用异戊胺合成亚硝胺的实验方法,以及用气相色谱/质谱和气相色谱/热能分析器分析的结果。     

MALIGNANT TRANSFORMATION OF BABY HAMSTER LUNG FIBROBLASTS INDUCED IN VITRO BY A NEW NITROSAMINE COMPOUND

A new nitrosamine compound, N-1-methylacetonyl-N-3-methylbutyl-nitrosamine (MAMB-NA), isolated from corn bread inoculated with moulds commonly occurring in Linxian County,a high incidence area for esophageal cancer in North China was tested for its potentialcarcinogenicity in vitro. Baby hamster lung fibroblasts (BHL) were treated with MAMBNAin tissue culture medium containing liver microsome preparation of Aroclor 1254 treatedrat. Cell transformation was assessed by morphological changes, loss of density-dependentinhibition and unlimited growth in vitro, chromosome changes, colony formation on softagar, growth at low serum concentration, Con A agglutinability and tumor formation afterheterotransplantation into immunosuppressed newborne rats. Like the known carcinogensN-methyl-N'-nitro-N-nitroso-guanidine and diethylnitrosamine, MAMBNA was able to causemalignant transformation of cells cultured in vitro.