Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-46441
Blom, J F; Zimmermann, Y S; Ammann, T; Pernthaler, J (2010). Scent of danger: floc formation by a freshwater bacterium is induced by supernatants from a predator-prey coculture. Applied and Environmental Microbiology, 76(18):6156-6163.
We investigated predator-prey interactions in a model system consisting of the bacterivorous flagellate Poterioochromonas sp. strain DS and the freshwater bacterium Sphingobium sp. strain Z007. This bacterial strain tends to form a subpopulation of grazing-resistant microscopic flocs, presumably by aggregation. Enhanced formation of such flocs could be demonstrated in static batch culture experiments in the presence of the predator. The ratio of aggregates to single cells reached >0.1 after 120 h of incubation in an oligotrophic growth medium. The inoculation of bacteria into supernatants from cocultures of bacteria and flagellates (grown in oligotrophic or in rich media) also resulted in a substantially higher level of floc formation than that in supernatants from bacterial monocultures only. After separation of supernatants on a C(18) cartridge, the aggregate-inducing activity could be assigned to the 50% aqueous methanolic fraction, and further separation of this bioactive fraction could be achieved by high-pressure liquid chromatography. These results strongly suggest the involvement of one or several chemical factors in the induction of floc formation by Sphingobium sp. strain Z007 that are possibly released into the surrounding medium by flagellate grazing.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||07 Faculty of Science > Institute of Plant Biology|
|DDC:||580 Plants (Botany)|
|Deposited On:||24 Feb 2011 18:30|
|Last Modified:||26 Nov 2012 23:44|
|Publisher:||American Society for Microbiology|
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