SURVIVAL STRATEGY OF ESCHERICHIA-COLI AND ENTEROCOCCUS-FAECALIS IN ILLUMINATED FRESH AND MARINE SYSTEMS
SURVIVAL STRATEGY OF ESCHERICHIA-COLI AND ENTEROCOCCUS-FAECALIS IN ILLUMINATED FRESH AND MARINE SYSTEMS
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DOI：
10.1111/j.1365-2672.1990.tb02565.x
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发表时间：
1990-02-01
期刊：
影响因子：
--
通讯作者：
EGEA, L
中科院分区：
文献类型：
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作者：
BARCINA, I;GONZALEZ, JM;EGEA, L
采用平板计数法、菌落面积法和直接计数法研究了可见光对天然淡水和海水中大肠杆菌和粪肠球菌的影响。大量的somnicells（不可培养的细胞）指出，在照明系统相比，非照明的。菌落面积显着较小的照明系统。采用间接活性测定法研究了可见光对E.大肠杆菌和粪肠球菌在天然沃茨中代谢底物（[14 C]葡萄糖）。在光照系统中，观察到葡萄糖摄取减少。当分析同化和呼吸相对于总葡萄糖摄取的百分比时，观察到同化百分比降低和呼吸百分比增加。此外，还检测到大肠杆菌在葡萄糖摄取、同化和呼吸方面的差异。大肠杆菌在新鲜和海水之间的实验开始时，这些被解释为海水对大肠杆菌的毒性作用。coli细胞。物种之间的差异，自然沃茨和参数的研究（除葡萄糖同化）中检测到的照明系统。然而，我们得出结论，可见光照射下的肠道细菌显示出一般的生存策略，其特征在于逐渐达到睡眠细胞阶段，其可以根据它们（1）不能在标准细菌培养基上形成菌落，（2）不能掺入底物，和（3）生物合成过程失活来定义。
Some effects of visible light on Escherichia coli and Enterococcus faecalis in natural freshwater and seawater were studied by plate counts, colony area measurements, and direct counts. A large number of somnicells (non-culturable cells) were noted in illuminated systems as compared with non-illuminated ones. Colony areas were significantly smaller in illuminated systems. Indirect activity measurements were used to test the effects of visible light on the ability of E. coli and Ent. faecalis to metabolize substrates ([14C]glucose) in natural waters. In illuminated systems, a decrease of glucose uptake was observed. When percentages of assimilation and respiration with respect to the total glucose uptake were analyzed a decrease of assimilation percentages and an increase of respiration percentages were observed. In addition, differences in glucose uptake, assimilation and respiration by enteric bacteria were detected for E. coli at the beginning of the experiments between fresh- and seawater and these were interpreted as a toxic effect exerted by seawater on E. coli cells. Differences between species, natural waters and parameters studied (excepting glucose assimilation) were detected in the illuminated systems. We concluded, however, that enteric bacteria under visible light illumination show a general survival strategy characterized by reaching progressively a somnicell stage which can be defined in terms of their (1) inability to form colonies on standard bacteriological media, (2) inability to incorporation substrates, and (3) inactivation of biosynthetic processes.