|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 199, Issue 5 1029-1041, Copyright © 1996 by Company of Biologists
JOURNAL ARTICLES |
E. Tambutte, D. Allemand, E. Mueller and J. Jaubert
Ca2+ compartments, Ca2+ transport and the calcification process were studied by using 45Ca as a tracer. The biological model used was clones of Stylophora pistillata developed into microcolonies whose skeleton is entirely covered by tissues, thus avoiding direct radioisotope exchange between the sea water and the skeleton. The study of Ca2+ compartments was performed by measuring two complementary parameters: Ca2+ influx and Ca2+ efflux kinetics. Kinetic analysis of 45Ca uptake revealed three exchangeable and one non-exchangeable Ca2+ compartments in these microcolonies. The first compartment was saturable with a short half-time (4 min), correlated to external Ca2+ concentration and insensitive to metabolic or ion transport inhibitors. This compartment (72.88 nmol Ca2+ mg-1 protein) has been previously attributed to sea water present in the coelenteron. The second Ca2+ compartment (7.12 nmol Ca2+ mg-1 protein) was soluble in NaOH, saturable with a half-time of 20 min and displayed a combination of Michaelis-Menten kinetics and diffusional entry. It was insensitive to a variety of inhibitors but its loading was stimulated by Ca2+ channel inhibitors. On the basis of uptake experiments, the existence of a third compartment with a rapid turnover rate (about 2 min) and a very small size is predicted. It is suggested that this compartment corresponds to the calicoblastic epithelium. Ca2+ flux through this compartment was facilitated by voltage-dependent Ca2+ channels (with L-type characteristics) and Ca2+-ATPase and was coupled to an anion carrier. Transcellular Ca2+ movement was dependent on the cytoskeleton. The rate of Ca2+ flux across this epithelium was about 975 pmol mg-1 protein min-1. The fourth calcium compartment, corresponding to the skeleton, was soluble in HCl and non-exchangeable. After a short lag phase (about 2 min), the rate of Ca2+ deposition was linear over a period of at least 5 h. The calcification rate was 975 pmol mg-1 protein h-1 at an irradiance of 175 micromole photons m-2 s-1. It followed Michaelis-Menten kinetics and saturated at levels (9 mmol l-1) close to the Ca2+ concentration of sea water. Wash-out (efflux) experiments employing several different protocols allowed identification of six compartments. The first two compartments were extracellular (bulk extracolonial water and coelenteron). The third compartment may be part of the second Ca2+ compartment identified by influx experiments. A fourth compartment was sensitive to the Ca2+ channel inhibitor D600 and appeared to be associated with the NaOH- soluble (tissue) Ca2+ pool. Two compartments were identified during skeletal efflux, the first being small and due to either tissue carry-over or a labile skeletal compartment. The second compartment corresponded to bulk skeletal deposition. The various efflux protocols produced varying estimates of tissue Ca2+ levels and calcification rates and, thus, coral post- incubation processing has a profound impact on experimental interpretation.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  A. Bertucci, E. Tambutte, S. Tambutte, D. Allemand, and D. Zoccola Symbiosis-dependent gene expression in coral-dinoflagellate association: cloning and characterization of a P-type H+-ATPase gene Proc R Soc B, September 30, 2009; (2009) rspb.2009.1266v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Brownlee pH regulation in symbiotic anemones and corals: A delicate balancing act PNAS, September 29, 2009; 106(39): 16541 - 16542. [Full Text] [PDF]
|
|
|
|
 |
|
 A. Moya, S. Tambutte, A. Bertucci, E. Tambutte, S. Lotto, D. Vullo, C. T. Supuran, D. Allemand, and D. Zoccola Carbonic Anhydrase in the Scleractinian Coral Stylophora pistillata: CHARACTERIZATION, LOCALIZATION, AND ROLE IN BIOMINERALIZATION J. Biol. Chem., September 12, 2008; 283(37): 25475 - 25484. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. T. Marshall, P. L. Clode, R. Russell, K. Prince, and R. Stern Electron and ion microprobe analysis of calcium distribution and transport in coral tissues J. Exp. Biol., July 15, 2007; 210(14): 2453 - 2463. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Moya, S. Tambutte, E. Tambutte, D. Zoccola, N. Caminiti, and D. Allemand Study of calcification during a daily cycle of the coral Stylophora pistillata: implications for `light-enhanced calcification' J. Exp. Biol., September 1, 2006; 209(17): 3413 - 3419. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Houlbreque, E. Tambutte, D. Allemand, and C. Ferrier-Pages Interactions between zooplankton feeding, photosynthesis and skeletal growth in the scleractinian coral Stylophora pistillata J. Exp. Biol., April 1, 2004; 207(9): 1461 - 1469. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. L. Cohen, A. L. Cohen, and T. A. McConnaughey Geochemical Perspectives on Coral Mineralization Reviews in Mineralogy and Geochemistry, January 1, 2003; 54(1): 151 - 187. [Full Text] [PDF]
|
|
|
|
|
|
P. L. Clode and A. T. Marshall Low temperature X-ray microanalysis of calcium in a scleractinian coral: evidence of active transport mechanisms J. Exp. Biol., November 15, 2002; 205(22): 3543 - 3552. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. T. Marshall and P. L. Clode Effect of increased calcium concentration in sea water on calcification and photosynthesis in the scleractinian coral Galaxea fascicularis J. Exp. Biol., July 15, 2002; 205(14): 2107 - 2113. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. J. Domart-Coulon, D. C. Elbert, E. P. Scully, P. S. Calimlim, and G. K. Ostrander Aragonite crystallization in primary cell cultures of multicellular isolates from a hard coral, Pocillopora damicornis PNAS, September 26, 2001; (2001) 211439698. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. L. Rogers and M. B. Thomas Calcification in the planula and polyp of the hydroid Hydractinia symbiolongicarpus (Cnidaria, Hydrozoa) J. Exp. Biol., January 8, 2001; 204(15): 2657 - 2666. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P Furla, I Galgani, I Durand, and D Allemand Sources and mechanisms of inorganic carbon transport for coral calcification and photosynthesis J. Exp. Biol., January 11, 2000; 203(22): 3445 - 3457. [Abstract] [PDF]
|
|
|
|
|
|
I. J. Domart-Coulon, D. C. Elbert, E. P. Scully, P. S. Calimlim, and G. K. Ostrander Aragonite crystallization in primary cell cultures of multicellular isolates from a hard coral, Pocillopora damicornis PNAS, October 9, 2001; 98(21): 11885 - 11890. [Abstract] [Full Text] [PDF]
|
|
