Universität zu Köln

Juettner, Friedrich, Watson, Susan B., von Elert, Eric ORCID: 0000-0001-7758-716X and Koester, Oliver (2010). beta-Cyclocitral, a Grazer Defence Signal Unique to the Cyanobacterium Microcystis. J. Chem. Ecol., 36 (12). S. 1387 - 1398. DORDRECHT: SPRINGER. ISSN 1573-1561

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Abstract

beta-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 beta-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 beta-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 beta-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 beta-cyclocitral/cell), corresponding to a calculated maximum intracellular concentration of 2.2 mM. The behavioral response of Daphnia magna to beta-cyclocitral was evaluated in a bbe (c) Daphnia toximeter, where beta-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 beta-cyclocitral. The minimum VOC concentration (odor threshold) that elicited a significant grazer response was 750 nM beta-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 beta-cyclocitral microzone around Microcystis colonies, thus acting as both a powerful repellent and signal of poor quality food to grazers.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Juettner, Friedrich UNSPECIFIED UNSPECIFIED UNSPECIFIED Watson, Susan B. UNSPECIFIED UNSPECIFIED UNSPECIFIED von Elert, Eric UNSPECIFIED orcid.org/0000-0001-7758-716X UNSPECIFIED Koester, Oliver UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-491628
DOI:	10.1007/s10886-010-9877-0
Journal or Publication Title:	J. Chem. Ecol.
Volume:	36
Number:	12
Page Range:	S. 1387 - 1398
Date:	2010
Publisher:	SPRINGER
Place of Publication:	DORDRECHT
ISSN:	1573-1561
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language FOOD SELECTION; ODOR COMPOUNDS; DAPHNIA-MAGNA; GREEN-ALGAE; AERUGINOSA; ZOOPLANKTON; WATER; TOXICITY; MECHANISMS; MORPHOLOGY Multiple languages Biochemistry & Molecular Biology; Ecology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/49162