The ctenidium of the giant clam, Tridacna squamosa, expresses an ammonium transporter 1 that displays light-suppressed gene and protein expression and may be involved in ammonia excretion
| Autor: | Wai P. Wong, Celine Y. L. Choo, Yuen K. Ip, Enan J. K. Goh, Mel V. Boo, Kum C. Hiong, Shit F. Chew |
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| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Light Physiology 01 natural sciences Biochemistry Excretion 03 medical and health sciences chemistry.chemical_compound Ammonia Endocrinology Glutamine synthetase Ammonium Compounds Animals Ammonium Amino Acid Sequence Cation Transport Proteins Ecology Evolution Behavior and Systematics chemistry.chemical_classification Base Sequence 010604 marine biology & hydrobiology Ctenidium Biological Transport Bivalvia Amino acid 030104 developmental biology Gene Expression Regulation chemistry Darkness Urea Animal Science and Zoology |
| Zdroj: | Journal of Comparative Physiology B. 188:765-777 |
| ISSN: | 1432-136X 0174-1578 |
| DOI: | 10.1007/s00360-018-1161-6 |
| Popis: | Ammonium transporters (AMTs) can participate in ammonia uptake or excretion across the plasma membrane of prokaryotic, plant and invertebrate cells. The giant clam, Tridacna squamosa, harbors nitrogen-deficient symbiotic zooxanthellae, and normally conducts light-enhanced ammonia absorption to benefit the symbionts. Nonetheless, it can excrete ammonia when there is a supply of exogenous nitrogen or exposed to continuous darkness. This study aimed to elucidate the role of AMT1 in the ctenidium of T. squamosa by cloning and characterizing the AMT1/AMT1, determining its subcellular localization, and examining changes in its transcript and protein expression levels in response to light exposure. The cDNA coding sequence of AMT1 from T. squamosa consisted of 1527 bp and encoded 508 amino acids of 54.6 kDa. AMT1-immunofluorescence was detected mainly at the apical epithelium of ctenidial filaments, and it decreased significantly after 12 h of exposure to light. By contrast, the epithelial cells surrounding the tertiary water channels in the ctentidium, which are known to exhibit light-enhanced glutamine synthetase expression and take part in the assimilation of exogenous ammonia in light, did not display any AMT1-immunolabelling. Furthermore, the transcript level and protein abundance of ctenidial AMT1/AMT1 decreased significantly at the 6th and 12th h of light exposure. Taken together, these results indicate that AMT1 might participate in ammonia excretion instead of ammonia absorption and assimilation in T. squamosa. It is probable that the expression levels of AMT1/AMT1 need to be down-regulated during light exposure to achieve light-enhanced ammonia uptake. |
| Databáze: | OpenAIRE |
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