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Dissociation of Circadian and Circatidal Timekeeping in the Marine Crustacean Eurydice pulchra

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posted on 31.10.2013, 09:46 by Lin Zhang, Michael H. Hastings, Edward W. Green, Eran Tauber, Martin Sladek, Simon G. Webster, Charalambos P. Kyriacou, David C. Wilcockson
Background: Tidal (12.4 hr) cycles of behavior and physiology adapt intertidal organisms to temporally complex coastal environments, yet their underlying mechanism is unknown. However, the very existence of an independent “circatidal” clock has been disputed, and it has been argued that tidal rhythms arise as a submultiple of a circadian clock, operating in dual oscillators whose outputs are held in antiphase i.e., ∼12.4 hr apart. Results: We demonstrate that the intertidal crustacean Eurydice pulchra (Leach) exhibits robust tidal cycles of swimming in parallel to circadian (24 hr) rhythms in behavioral, physiological and molecular phenotypes. Importantly, ∼12.4 hr cycles of swimming are sustained in constant conditions, they can be entrained by suitable stimuli, and they are temperature compensated, thereby meeting the three criteria that define a biological clock. Unexpectedly, tidal rhythms (like circadian rhythms) are sensitive to pharmacological inhibition of Casein kinase 1, suggesting the possibility of shared clock substrates. However, cloning the canonical circadian genes of E. pulchra to provide molecular markers of circadian timing and also reagents to disrupt it by RNAi revealed that environmental and molecular manipulations that confound circadian timing do not affect tidal timing. Thus, competent circadian timing is neither an inevitable nor necessary element of tidal timekeeping. Conclusions: We demonstrate that tidal rhythms are driven by a dedicated circatidal pacemaker that is distinct from the circadian system of E. pulchra, thereby resolving a long-standing debate regarding the nature of the circatidal mechanism.

Funding

C.P.K. and S.G.W. thank the BBSRC for funding (91/517172, BBE0017501, BB/E000835/1, and BB/K009702/1) and the College of Medicine and Biology at the University of Leicester for funding L.Z. for 1 year. M.H.H. was supported by the Medical Research Council, UK.

History

Citation

Current Biology, 2013, 23 (19), pp. 1863-1873

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Biological Sciences/Department of Genetics

Version

VoR (Version of Record)

Published in

Current Biology

Publisher

Elsevier (Cell Press)

issn

0960-9822

eissn

1879-0445

Copyright date

2013

Available date

31/10/2013

Publisher version

http://www.sciencedirect.com/science/article/pii/S0960982213010440

Language

en

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