Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/96408
Title: Relative contributions of vibrio polysaccharide and quorum sensing to the resistance of vibrio cholerae to predation by heterotrophic protists
Authors: Sun, Shuyang
Kjelleberg, Staffan
McDougald, Diane
Keywords: DRNTU::Science::Biological sciences::Genetics
Issue Date: 2013
Source: Sun, S., Kjelleberg, S., & McDougald, D. (2013). Relative Contributions of Vibrio Polysaccharide and Quorum Sensing to the Resistance of Vibrio cholerae to Predation by Heterotrophic Protists. PLoS ONE, 8(2).
Series/Report no.: PLoS ONE
Abstract: Protozoan grazing is a major mortality factor faced by bacteria in the environment. Vibrio cholerae, the causative agent of the disease cholera, is a natural inhabitant of aquatic ecosystems, and its survival depends on its ability to respond to stresses, such as predation by heterotrophic protists. Previous results show that grazing pressure induces biofilm formation and enhances a smooth to rugose morphotypic shift, due to increased expression of Vibrio polysaccharide (VPS). In addition to negatively controlling vps genes, the global quorum sensing (QS) regulator, HapR, plays a role in grazing resistance as the ΔhapR strain is efficiently consumed while the wild type (WT) is not. Here, the relative and combined contributions of VPS and QS to grazing resistance were investigated by exposing VPS and HapR mutants and double mutants in VPS and HapR encoding genes at different phases of biofilm development to amoeboid and flagellate grazers. Data show that the WT biofilms were grazing resistant, the VPS mutants were less resistant than the WT strain, but more resistant than the QS mutant strain, and that QS contributes to grazing resistance mainly in mature biofilms. In addition, grazing effects on biofilms of mixed WT and QS mutant strains were investigated. The competitive fitness of each strain in mixed biofilms was determined by CFU and microscopy. Data show that protozoa selectively grazed the QS mutant in mixed biofilms, resulting in changes in the composition of the mixed community. A small proportion of QS mutant cells which comprised 4% of the mixed biofilm biovolume were embedded in grazing resistant WT microcolonies and shielded from predation, indicating the existence of associational protection in mixed biofilms.
URI: https://hdl.handle.net/10356/96408
http://hdl.handle.net/10220/9894
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0056338
Rights: © 2013 The Author(s).
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:NEWRI Journal Articles
SBS Journal Articles

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