Seasonal and Successional Influences on Bacterial Community Composition Exceed That of Protozoan Grazing in River Biofilms
Seasonal and Successional Influences on Bacterial Community Composition Exceed That of Protozoan Grazing in River Biofilms
复制标题
DOI：
10.1128/aem.06517-11
复制
发表时间：
2012-01
影响因子：
4.4
通讯作者：
J. Wey;K. Jürgens;M. Weitere
中科院分区：
文献类型：
--
作者：
J. Wey;K. Jürgens;M. Weitere
摘要在自然背景条件下，采用粒径分级法，研究了原生动物（异养鞭毛虫和纤毛虫）对河流旁路系统中细菌生物膜形态和群落组成的影响。共聚焦激光扫描显微镜（CLSM）被用来监测生物膜的形态结构，和指纹方法（单链构象多态性[SSCP]和变性梯度凝胶电泳[DGGE]）被用来评估细菌群落组成的变化。季节和内部种群动态对细菌生物膜的影响比原生动物的存在更大。在这一总体框架内，细菌面积覆盖率和微菌落丰度仍然增强了纤毛虫的存在（但不是鞭毛虫的存在）。我们还发现，丰富的细菌操作分类单位是更高的，在浮游生物的创始人社区比在建立生物膜。在第一个2小时的空基板的细菌定植，鞭毛虫的存在下，另外改变了他们的生物膜群落组成。随着生物膜的成熟，当鞭毛虫以高丰度存在时，细菌操作分类单位的数量增加。纤毛虫的额外存在往往在第一次减少（第2至7天），后来增加（第14至29天）细菌操作分类单位丰富度。总而言之，原生动物放牧压力的细菌群落的反应是小的相比，在aptotonic研究报告，但我们的研究结果相矛盾的假设细菌生物膜对原生动物的一般放牧阻力。
ABSTRACT The effects of protozoa (heterotrophic flagellates and ciliates) on the morphology and community composition of bacterial biofilms were tested under natural background conditions by applying size fractionation in a river bypass system. Confocal laser scanning microscopy (CLSM) was used to monitor the morphological structure of the biofilm, and fingerprinting methods (single-stranded conformation polymorphism [SSCP] and denaturing gradient gel electrophoresis [DGGE]) were utilized to assess changes in bacterial community composition. Season and internal population dynamics had a greater influence on the bacterial biofilm than the presence of protozoa. Within this general framework, bacterial area coverage and microcolony abundance were nevertheless enhanced by the presence of ciliates (but not by the presence of flagellates). We also found that the richness of bacterial operational taxonomic units was much higher in planktonic founder communities than in the ones establishing the biofilm. Within the first 2 h of colonization of an empty substrate by bacteria, the presence of flagellates additionally altered their biofilm community composition. As the biofilms matured, the number of bacterial operational taxonomic units increased when flagellates were present in high abundances. The additional presence of ciliates tended to at first reduce (days 2 to 7) and later increase (days 14 to 29) bacterial operational taxonomic unit richness. Altogether, the response of the bacterial community to protozoan grazing pressure was small compared to that reported in planktonic studies, but our findings contradict the assumption of a general grazing resistance of bacterial biofilms toward protozoa.