Effects of autochthonous microbial community on the die-off of fecal indicators in tropical beach sand
Effects of autochthonous microbial community on the die-off of fecal indicators in tropical beach sand
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DOI：
10.1111/j.1574-6941.2010.00921.x
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发表时间：
2010-10-01
影响因子：
4.2
通讯作者：
Yan, Tao
中科院分区：
文献类型：
--
作者：
Feng, Fan;Goto, Dustin;Yan, Tao
最近观察到海滩沙子中粪便指标含量很高，这使海滩水监测工作陷入混乱。粪便指标的高水平可能是由于控制沙中死亡的常见环境压力的损失或活动减少造成的。进行了微观世界实验，以比较来自两个热带海滩沙子中的原生沙细菌、原生动物和病毒的生物胁迫对大肠杆菌和粪肠球菌的影响。放线菌酮对原生动物活性的抑制并未显着影响大肠杆菌的死亡，表明原生动物捕食在滩沙中发挥的作用有限。噬菌体感染对大肠杆菌死亡的影响也可以忽略不计。因此，本土细菌被确定为导致海滩沙子中大肠杆菌死亡的主要生物胁迫。随后的实验表明，与各种环境样本相比，海滩沙子的原生动物浓度非常低，原生动物的生长潜力也很低。大肠杆菌与本地沙细菌分离株的共培养显着促进了大肠杆菌的死亡。 PCR-变性梯度凝胶电泳分析揭示了复杂的沙细菌群落，表明细菌拮抗作用可能广泛存在。研究还发现，与大肠杆菌相比，粪肠球菌在海滩沙子中的存活时间要长得多。
The recently observed high levels of fecal indicators in beach sand confound beach water monitoring efforts. The high levels of fecal indicators may be caused by the loss or the reduced activities of common environmental stresses controlling die-off in the sand. Microcosm experiments were conducted to compare the effects of biotic stresses from autochthonous sand bacteria, protozoa, and viruses on Escherichia coli and Enterococcus faecalis in two tropical beach sands. The inhibition of protozoan activities by cycloheximide did not significantly affect the die-off of E. coli, indicating that protozoan predation played a limited role in beach sand. The contribution from phage infection to E. coli die-off was also negligible. Consequently, autochthonous bacteria were identified as the predominant biotic stress to the die-off of E. coli in beach sand. Subsequent experiments demonstrated that the beach sand had a very low protozoan concentration and low protozoan growth potential when compared with various environmental samples. Co-culturing of E. coli with autochthonous sand bacterial isolates significantly enhanced E. coli die-off. PCR-denaturing gradient gel electrophoresis analysis revealed a complex sand bacterial community, suggesting that bacterial antagonistic effects may be widespread. The study also found that E. faecalis exhibited a much longer survival in beach sand compared with E. coli.