| β-cyclocitral, a grazer defence signal unique to the cyanobacterium Microcystis. | |
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MedLine Citation:
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PMID: 21072572 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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β-Cyclocitral is often present in eutrophic waters and is a well known source of airborne and drinking water malodor, but its production and functional ecology are unresolved. This volatile organic compound (VOC) is derived from the catalytic breakdown of β-carotene, and evidence indicates that it is produced by the activation of a specific carotene oxygenase by all species of the bloom-forming cyanobacterium Microcystis. Previous work has shown that β-cyclocitral affects grazer behavior, but the nature of this interaction and its influence on predator-prey dynamics was unresolved. The present study combined analytical and behavioral studies to evaluate this interaction by using Microcystis NRC-1 and Daphnia magna. Results showed that β-cyclocitral was undetectable in live Microcystis cells, or present only at extremely low concentrations (2.6 amol /cell). In contrast, cell rupture activated a rapid carotene oxygenase reaction, which produced high amounts (77 ± 5.5 amol β-cyclocitral/cell), corresponding to a calculated maximum intracellular concentration of 2.2 mM. The behavioral response of Daphnia magna to β-cyclocitral was evaluated in a bbe© Daphnia toximeter, where β-cyclocitral treatments induced a marked increase in swimming velocity. Acclimation took place within a few minutes, when Daphnia returned to normal swimming velocity while still exposed to β-cyclocitral. The minimum VOC concentration (odor threshold) that elicited a significant grazer response was 750 nM β-cyclocitral, some 2,900 times lower than the per capita yield of a growing Microcystis cell after activation. Under natural conditions, initial grazer-related or other mode of cell rupture would lead to the development of a robust β-cyclocitral microzone around Microcystis colonies, thus acting as both a powerful repellent and signal of poor quality food to grazers. |
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Authors:
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Friedrich Jüttner; Susan B Watson; Eric von Elert; Oliver Köster |
Publication Detail:
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Type: Journal Article Date: 2010-11-12 |
Journal Detail:
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Title: Journal of chemical ecology Volume: 36 ISSN: 1573-1561 ISO Abbreviation: J. Chem. Ecol. Publication Date: 2010 Dec |
Date Detail:
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Created Date: 2010-12-24 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7505563 Medline TA: J Chem Ecol Country: United States |
Other Details:
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Languages: eng Pagination: 1387-97 Citation Subset: IM |
Affiliation:
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University of Zürich, Limnological Station, Kilchberg, Switzerland. juttner@limnol.uzh.ch |
Export Citation:
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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