Mallett A K, Rowland I R, Bearne C A, Purchase R, Gangolli S D
Food Chem Toxicol. 1985 Dec;23(12):1029-34. doi: 10.1016/0278-6915(85)90048-1.
Previous studies have demonstrated that the rat faecal microflora maintained in vitro under conditions of continuous flow possesses bacteriological and metabolic characteristics similar to those of the native bacterial population of the caecum. Addition of sodium cyclamate (75 mM) to the culture concurrent with the progressive dilution of the growth medium promoted metabolism of cyclamate to cyclohexylamine (sulphamatase activity) within 4 wk. The maximum formation of cyclohexylamine was attained in about 8 wk and was equivalent to a 2-3% molar conversion of cyclamate to cyclohexylamine. The recovery of viable cells from the culture and the total microscopic count decreased during the adaptation period, although the relative proportions of the major bacterial types remained unchanged. Concurrent with the increase in sulphamatase activity, other enzyme functions (as assessed by the API-zym system) decreased markedly. The ability to hydrolyse cyclamate to cyclohexylamine developed independently of other bacterial biotransformation enzymes in vitro, and was not associated with any gross taxonomic changes. These studies demonstrate the suitability of continuous culture systems for investigating the metabolic activity of the rat gut flora.
先前的研究表明，在连续流动条件下体外培养的大鼠粪便微生物群具有与盲肠天然细菌群体相似的细菌学和代谢特征。在生长培养基逐步稀释的同时，向培养物中添加甜蜜素（75 mM）可在4周内促进甜蜜素代谢为环己胺（硫酸酯酶活性）。环己胺的最大生成量在约8周时达到，相当于甜蜜素向环己胺的2-3%摩尔转化率。在适应期，培养物中活细胞的回收率和总显微镜计数下降，尽管主要细菌类型的相对比例保持不变。与硫酸酯酶活性增加同时，其他酶功能（通过API-zym系统评估）显著下降。在体外，将甜蜜素水解为环己胺的能力独立于其他细菌生物转化酶发展，且与任何总体分类学变化无关。这些研究证明了连续培养系统适用于研究大鼠肠道菌群的代谢活性。
