Please use this identifier to cite or link to this item: http://hdl.handle.net/10497/22103
Title: 
Authors: 
Keywords: 
Bicarbonate
Calcification
Shell formation
Symbiodinium
Zooxanthellae
Issue Date: 
2019
Citation: 
Cao-Pham, A. H., Hiong, K. C., Boo, M. V., Choo, C. Y. L., Wong, W. P., Chew, S. F., & Ip, Y. K. (2019). Calcium absorption in the fluted giant clam, Tridacna squamosa, may involve a homolog of voltage-gated calcium channel subunit α1 (CACNA1) that has an apical localization and displays light-enhanced protein expression in the ctenidium. Journal of Comparative Physiology B, 189(6), 693-706. https://doi.org/10.1007/s00360-019-01238-4
Abstract: 
In light, giant clams can increase rates of shell formation and growth due to their symbiotic relationship with phototrophic zooxanthellae residing extracellularly in a tubular system. Light-enhanced shell formation necessitates increase in the uptake of Ca2+ from the ambient seawater and the supply of Ca2+ through the hemolymph to the extrapallial fluid, where calcification occurs. In this study, the complete coding cDNA sequence of a homolog of voltage-gated calcium channel subunit α1 (CACNA1), which is the pore-forming subunit of L-type voltage-gated calcium channels (VGCCs), was obtained from the ctenidium (gill) of the giant clam, Tridacna squamosa. It consisted of 6081 bp and encoded a 223 kDa polypeptide with 2027 amino acids, which was characterized as the α1D subunit of L-type VGCC. Immunofluorescence microscopy demonstrated that CACNA1 had an apical localization in the epithelial cells of filaments and tertiary water channels in the ctenidium of T. squamosa, indicating that it was well positioned to absorb exogenous Ca2+. Additionally, there was a significant increase in the protein abundance of CACNA1 in the ctenidium of individuals exposed to light for 12 h. With more pore-forming CACNA1, there could be an increase in the permeation of exogenous Ca2+ into the ctenidial epithelial cells through the apical membrane. Taken together, these results denote that VGCC could augment exogenous Ca2+ uptake through the ctenidium to support light-enhanced shell formation in T. squamosa. Furthermore, they support the proposition that light-enhanced phenomena in giant clams are attributable primarily to the direct responses of the host’s transporters/enzymes to light, in alignment with the symbionts’ phototrophic activity.
Description: 
This is the final draft, after peer-review, of a manuscript published in Journal of Comparative Physiology B. The published version is available online at https://doi.org/10.1007/s00360-019-01238-4
URI: 
ISSN: 
0174-1578 (print)
1432-136X (online)
Other Identifiers: 
10.1007/s00360-019-01238-4
Appears in Collections:Journal Articles

Files in This Item:
File Description SizeFormat 
JCPB-189-6-693.pdf
  Until 2020-10-31
4.56 MBAdobe PDFUnder embargo until Oct 31, 2020
Show full item record

Page view(s)

28
checked on Sep 23, 2020

Download(s)

1
checked on Sep 23, 2020

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.