Predatory Bacteriovorax communities ordered by various prey species

• Published in: PloS one 2012-03, Vol.7 (3), p.e34174-e34174
• Main Authors: Chen, Huan, Young, Shanterial, Berhane, Timkhite-Kulu, Williams, Henry N
• Format: Article
• Language: English
• Subjects: Aquatic environment; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteroidetes; Biology; Cholera toxin; Community composition; Deltaproteobacteria - genetics; Deltaproteobacteria - physiology; E coli; Ecosystem; Environmental parameters; Escherichia coli; Experiments; Fresh Water - microbiology; Gel electrophoresis; Gene amplification; Gene sequencing; Genomes; Gram-negative bacteria; Laboratories; Microbial activity; Microcosms; Microorganisms; Optical density; Phylogenetics; Phylogeny; Plaques; Population Dynamics; Predation; Predators; Prey; Prokaryotes; Pseudomonas putida; RNA; RNA, Ribosomal, 16S - genetics; rRNA 16S; Seawater - microbiology; Species Specificity; Strains (organisms); Studies; Subgroups; Vibrio; Vibrio parahaemolyticus; Vibrio parahaemolyticus - genetics; Vibrio parahaemolyticus - physiology; Vibrio vulnificus - genetics; Vibrio vulnificus - physiology; Water analysis; Water Microbiology; Water sampling; Waterborne diseases
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0034174

The role of predation in altering microbial communities has been studied for decades but few examples are known for bacterial predators. Bacteriovorax are halophilic prokaryotes that prey on susceptible gram-negative bacteria. We recently reported novel observations on the differential selection of Bacteriovorax phylotypes by two different prey, Vibrio parahaemolyticus and Vibrio vulnificus. However, the conclusion is restricted by the limited number of prey tested. In this study, we have conducted two independent investigations involving eight species of prey bacteria while using V. vulnificus and V. parahaemolytics as reference strains. Water samples collected from Dry Bar, Apalachicola Bay were used to establish microcosms which were respectively spiked with prey strains Vibrio cholerae, Escherichia coli or Pseudomonas putida to examine the response of native Bacteriovorax to freshwater bacteria. Indigenous Vibrio sp., Pseudoalteromonas sp., Photobacterium sp. and a clinical strain of V. vulnificus were also tested for the impact of saltwater prey on the Bacteriovorax community. At 24 hour intervals, optical density of the microcosm samples and the abundance of Bacteriovorax were measured over five days. The predominant Bacteriovorax plaques were selected and analyzed by 16S rRNA gene amplification and sequencing. In addition, the impacts of prey on predator population and bacterial community composition were investigated using culture independent denaturing gradient gel electrophoresis. Strikingly, Cluster IV was found consistently as the predominant phylotype produced by the freshwater prey. For all saltwater prey, subgroups of Bacteriovorax phylotype IX were the major predators recovered. The results suggest that prey is an important factor along with temperature, salinity and other environmental parameters in shaping Bacteriovorax communities in aquatic systems.