Studies on microorganisms in fermented seafoods

对日本几种传统发酵鱼制品的微生物特性进行了研究。研究结果如下：(1)对从草草肉汁中分离得到的螺旋菌的表型、化学分类和系统发育特征进行了详细的研究，表明它们应该属于一个新属，与每个已知物种都有足够的系统发育距离。因此我们将其命名为Marinospirillum megaterium sp.nov。对于分离株，创建一个新属。(2)采用16SrRNA基因的遗传鉴定分组方法，分析了藜草菜地微生物种群。克隆的部分16SrDNA序列分析表明，肉汁中的主要细菌为拟杆菌-噬细胞菌群、无壁螺旋体样细菌等。结果表明，肉汁中存在多种未知和不可培养的微生物。(3)研究了影响芝麻熟成的乳酸、乙酸等有机酸在芝麻熟成过程中的积累情况，发现优势微生物能在芝麻熟成过程中形成有机酸。我们还明确了一些接种到shiokara的菌株，副溶血性弧菌，肉毒杆菌，金黄色葡萄球菌没有在其中生长。(4)对葡萄球菌和微球菌的三种培养方法进行了鉴定。结果证实葡萄糖OF试验（Baird-Parker法）是一种误导方法，而同时使用FP和SK琼脂可用于常规鉴定系统。(5)从咸鱼子房分离的一株严格厌氧和中度嗜盐细菌被认为是一新种。在米糠发酵鱼子房的发酵过程中，分离到了嗜盐四芽球菌和穆里蒂卡菌。

Microbiological characteristics of several traditional fermented fish products in Japan were studied. The results are as follows;(1) A detailed investigation of the phenotypic, chemotaxonomic and phylogenetic characteristics of the helical bacteria isolated from kusaya gravy revealed that they should belong to a new genus, with enough phylogenetic distance from each of the known species. So we proposed the name Marinospirillum megaterium sp.nov. for the isolates, with a creation of a new genus.(2) Microbial poulation in kusaya garavy was analyzed by grouping of genetic identification from 16SrRNA gene. Sequence analysis of cloned partial 16SrDNA indicated that the major bacteria in the gravy were Bacteroides-Cytophaga group, wall less spirohaeta-like bacteria, etc. The results indicated that there are diverse organisms which are unknown and unculturable in the gravy.(3) Accumulation of organic acids such as lactic acid, acetic acid, etc., which might contribute to the preservability and taste of shiokara, during the ripening of shiokara was studied and it was found that the dominant microoraganisms could form organic acids in shiokara. We also made clear that some inoculated strains into shiokara of Vibrio parahaemolyticus, Clostridium botulinum, Staphylococcus aureus did not grow in it.(4) Three culture methods for the differentiation of Staphylococcus and Micrococcus were evaluated. The results confirmed that OF test of glucose (Baird-Parker's method) is misleading method, while simultaneous use of FP & SK agar was suggested to be useful in routine identification system.(5)A strain of strictly anaerobic and moderately halophilic bacteria isolated from salted fish ovaries was considered to be a new species. We proposed for it the name Haloanaerobium fermentans sp. nov. Both Tetragenococcus halophilus and T. muriaticus were isolated during the fermentation process of fermented fish ovaries with rice-bran.