The fluted giant clam (Tridacna squamosa) increases the protein abundance of the host's copper-zinc superoxide dismutase in the colorful outer mantle, but not the whitish inner mantle, during light exposure.

The colorful outer mantle of giant clams contains abundance of symbiotic dinoflagellates (zooxanthellae) and iridocytes, and has direct exposure to light. In light, photosynthesizing dinoflagellates produce O, and the host cells in the outer mantle would be confronted with hyperoxia-related oxidative stress. In comparison, the whitish inner mantle contains few symbiotic dinoflagellates and no iridocytes.

Light-enhanced expression of Carbonic Anhydrase 4-like supports shell formation in the fluted giant clam Tridacna squamosa.

Giant clams represent symbiotic associations between a host clam and its extracellular zooxanthellae. They are able to grow in nutrient-deficient tropical marine environments and conduct light-enhanced shell formation (calcification) with the aid of photosynthates donated by the symbiotic zooxanthellae. In light, there is a high demand for inorganic carbon (C) to support photosynthesis in the symbionts and light-enhanced calcification in the host.

Molecular Characterization of a Dual Domain Carbonic Anhydrase From the Ctenidium of the Giant Clam, , and Its Expression Levels After Light Exposure, Cellular Localization, and Possible Role in the Uptake of Exogenous Inorganic Carbon.

A () had been sequenced and characterized from the ctenidia (gills) of the giant clam, , which lives in symbiosis with zooxanthellae. was expressed predominantly in the ctenidium. The complete cDNA coding sequence of from comprised 1,803 bp, encoding a protein of 601 amino acids and 66.

Carbonic anhydrase 2-like in the giant clam, : characterization, localization, response to light, and possible role in the transport of inorganic carbon from the host to its symbionts.

The fluted giant clam, , lives in symbiosis with zooxanthellae which reside extracellularly inside a tubular system. Zooxanthellae fix inorganic carbon (C) during insolation and donate photosynthate to the host. Carbonic anhydrases catalyze the interconversion of CO and HCO3-, of which carbonic anhydrase 2 (CA2) is the most ubiquitous and involved in many biological processes.