SEMINAR: TODAY: Visiting Scientist Seminar on Coral Biomineralization - Anthony Bertucci 11am

["Andrew Baker" <abaker@rsmas.miami.edu>]

Visiting Scientist Seminar

 

May 3, 2010 at 11 am

Seminar Room in SLAB

 

“The role of diverse carbonic anhydrases in coral biomineralization”

 

Anthony Bertucci

PhD candidate

Scientific Centre of Monaco

 

Carbonic anhydrases (CA) are metalloenzymes that catalyse the hydration of carbon dioxide into bicarbonate. Among numerous roles in physiological processes, CAs play an important role in biomineralization from invertebrates to vertebrates. Several studies have demonstrated the involvement of CAs in the calcification process of scleractinian corals.

 

We have cloned, sequenced and localized a CA in the scleractinian coral Stylophora pistillata, named STPCA. STPCA is a secreted form of alpha-CA and shares similarities with the secreted human hCAVI. We have shown that STPCA has a significant catalytic activity, comparable to hCAVI. STPCA is localized in the calicoblastic ectoderm, which is the epithelium responsible for coral calcification. We have also investigated the inhibition of STPCA by a series of inorganic anions, sulfonamides and sulphamates (such as acetazolamide) and its activation by amino acids and amines. The final form of inorganic carbon used for calcification, carbonate, is surprisingly among the best anion inhibitors. Among sulfonamides, saccharin showed a relative selectivity against STPCA and D-DOPA is the best activator tested here. These drugs may be useful to better understand the physiological role of the CAs in corals and their involvement in biomineralization.

 

Moreover, most scleractinian corals show a higher rate of calcification in the light than in the dark: a phenomenon known as light-enhanced calcification. We have shown that the STPCA gene is expressed 2-fold more during the night. We suggest that in the dark, this up-regulation represents a mechanism to cope with night acidosis at the site of calcification.

 

 

___________________

Andrew C. Baker, Ph.D.

Assistant Professor

Rosenstiel School of Marine and Atmospheric Science

University of Miami

4600 Rickenbacker Cswy.

Miami, FL 33149, USA

Office: +1 (305) 421-4642

Lab: +1 (305) 421-4226

Cell: +1 (305) 989-5488

Fax: +1 (305) 421-4600

Email: abaker@rsmas.miami.edu

 

Associate Conservation Scientist

Wildlife Conservation Society

www.wcs.org/marine

 

For more information on coral reef research at the University of Miami, visit:

The National Center for Coral Reef Research: ncore.rsmas.miami.edu