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Li Z, Yang M, Zhou C, Shi P, Hu P, Liang B, Jiang Q, Zhang L, Liu X, Lai C, Zhang T, Song H. Deciphering the molecular toolkit: regulatory elements governing shell biomineralization in marine molluscs. Integr Zool 2024. [PMID: 39030865 DOI: 10.1111/1749-4877.12876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2024]
Abstract
The intricate process of shell biomineralization in marine molluscs is governed by a complex interplay of regulatory elements, encompassing secretomes, transporters, and noncoding RNA. This review delves into recent advancements in understanding these regulatory mechanisms, emphasizing their significance in elucidating the functions and evolutionary dynamics of the molluscan shell biomineralization process. Central to this intricate orchestration are secretomes with diverse functional domains, selectively exported to the extrapallial space, which directly regulate crystal growth and morphology. Transporters are crucial for substrate transportation in the calcification and maintenance of cellular homeostasis. Beyond proteins and transporters, noncoding RNA molecules are integral components influencing shell biomineralization. This review underscores the nonnegligible roles played by these genetic elements at the molecular level. To comprehend the complexity of biomineralization in mollusc, we explore the origin and evolutionary history of regulatory elements, primarily secretomes. While some elements have recently evolved, others are ancient genes that have been co-opted into the biomineralization toolkit. These elements undergo structural and functional evolution through rapidly evolving repetitive low-complexity domains and domain gain/loss/rearrangements, ultimately shaping a distinctive set of secretomes characterized by both conserved features and evolutionary innovations. This comprehensive review enhances our understanding of molluscan biomineralization at the molecular and genetic levels.
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Affiliation(s)
- Zhuoqing Li
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Meijie Yang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Cong Zhou
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Pu Shi
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Pengpeng Hu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bin Liang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qingtian Jiang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Lili Zhang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiaoyan Liu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Qingdao Agricultural University, Qingdao, China
| | - Changping Lai
- Lianyungang Blue Carbon Marine Technology Co., Lianyungang, China
| | - Tao Zhang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hao Song
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
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Geng J, Yan H, Liu C, Han T, Liu S, Zhao N, Wen H, Yang H, Zhou P, Wang G, Dodson J. Reconstruction of ENSO variability using the standardized growth index of a Tridacna shell from Yongshu Reef, South China Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169118. [PMID: 38065507 DOI: 10.1016/j.scitotenv.2023.169118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 12/01/2023] [Accepted: 12/03/2023] [Indexed: 12/23/2023]
Abstract
El Niño-Southern Oscillation (ENSO) is the strongest signal of global interannual climate anomaly and reconstructing past ENSO variations using high-resolution paleoclimate archives can improve our understanding of ENSO variability, as well as improve our ability to predict future climate changes. Here, a daily resolution standardized growth index (SGI) was established using a giant clam (Tridacna spp.) shell specimen MD2 (life span: 1994-2013 CE), collected from the Yongshu Reef, southern South China Sea (SCS). The cross-spectral and correlation analysis indicated that the SGI variation of MD2 was strongly influenced by ENSO variability on an interannual timescale. Tridacna spp. is in symbiosis with zooxanthellae, and its growth index is usually modulated by the photosynthetic efficiency of zooxanthellae. During the El Niño (La Niña) period, the convective anomalies stimulated in western Pacific would increase (decrease) the effective solar radiation on Yongshu Reef, and in turn influence the photosynthesis rate of zooxanthellae and enzyme activity for the calcification site and thus the SGI of giant clam MD2. The SGI can explain 54.7 % of ENSO variance, demonstrating the potential for Tridacna SGI in ENSO reconstruction. Compared with conventional ENSO reconstruction using high-resolution geochemical proxies, the method of giant clam SGI is rapid and economical.
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Affiliation(s)
- Jun Geng
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Yan
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; Open Studio for Oceanic-Continental Climate and Environment Changes, Laoshan Laboratory, Qingdao 266237, China; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Chengcheng Liu
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; Xi'an Institute for Innovative Earth Environment Research, Xi'an 710061, China
| | - Tao Han
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; Xi'an Institute for Innovative Earth Environment Research, Xi'an 710061, China
| | - Shan Liu
- Xi'an Institute for Innovative Earth Environment Research, Xi'an 710061, China
| | - Nanyu Zhao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Hanfeng Wen
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haotian Yang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Pengchao Zhou
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Guozhen Wang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - John Dodson
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney 2052, Australia
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Mantilla G, Peréz-Gordones MC, Cisneros-Montufar S, Benaim G, Navarro JC, Mendoza M, Ramírez-Iglesias JR. Structural Analysis and Diversity of Calmodulin-Binding Domains in Membrane and Intracellular Ca2+-ATPases. J Membr Biol 2022; 256:159-174. [PMID: 36454258 DOI: 10.1007/s00232-022-00275-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 11/11/2022] [Indexed: 12/03/2022]
Abstract
The plasma membrane and autoinhibited Ca2+-ATPases contribute to the Ca2+ homeostasis in a wide variety of organisms. The enzymatic activity of these pumps is stimulated by calmodulin, which interacts with the target protein through the calmodulin-binding domain (CaMBD). Most information about this region is related to all calmodulin modulated proteins, which indicates general chemical properties and there is no established relation between Ca2+ pump sequences and taxonomic classification. Thus, the aim of this study was to perform an in silico analysis of the CaMBD from several Ca2+-ATPases, in order to determine their diversity and to detect specific patterns and amino acid selection in different species. Patterns related to potential and confirmed CaMBD were detected using sequences retrieved from the literature. The occurrence of these patterns was determined across 120 sequences from 17 taxonomical classes, which were analyzed by a phylogenetic tree to establish phylogenetic groups. Predicted physicochemical characteristics including hydropathy and net charge were calculated for each group of sequences. 22 Ca2+-ATPases sequences from animals, unicellular eukaryotes, and plants were retrieved from bioinformatic databases. These sequences allow us to establish the Patterns 1(GQILWVRGLTRLQTQ), 3(KNPSLEALQRW), and 4(SRWRRLQAEHVKK), which are present at the beginning of putative CaMBD of metazoan, parasites, and land plants. A pattern 2 (IRVVNAFR) was consistently found at the end of most analyzed sequences. The amino acid preference in the CaMBDs changed depending on the phylogenetic groups, with predominance of several aliphatic and charged residues, to confer amphiphilic properties. The results here displayed show a conserved mechanism to contribute to the Ca2+ homeostasis across evolution and may help to detect putative CaMBDs.
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Affiliation(s)
- Génesis Mantilla
- Research Group of Emerging and Neglected Diseases, Ecoepidemiology and Biodiversity. Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador
- Faculty of Engineering and Applied Sciences, Universidad Internacional SEK (UISEK), Quito, Ecuador
| | - María C Peréz-Gordones
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela
| | - Soledad Cisneros-Montufar
- Research Group of Emerging and Neglected Diseases, Ecoepidemiology and Biodiversity. Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador
- Faculty of Engineering and Applied Sciences, Universidad Internacional SEK (UISEK), Quito, Ecuador
| | - Gustavo Benaim
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela
- Instituto de Estudios Avanzados (IDEA), Caracas, Venezuela
| | - Juan-Carlos Navarro
- Research Group of Emerging and Neglected Diseases, Ecoepidemiology and Biodiversity. Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador
- Program of Master in Biomedicine, Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador
| | - Marta Mendoza
- Centro de Estudios Biomédicos y Veterinarios, Instituto de Estudios Científicos y Tecnológicos (IDECYT), Universidad Nacional Experimental Simón Rodríguez, Caracas, Venezuela
| | - José R Ramírez-Iglesias
- Research Group of Emerging and Neglected Diseases, Ecoepidemiology and Biodiversity. Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador.
- Program of Master in Biomedicine, Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador.
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Yu Y, Tian D, Han Y, Huang L, Tang Y, Zhang W, Zhou W, Shi W, Yu Y, Liu G. Impacts of microplastics and carbamazepine on the shell formation of thick-shell mussels and the underlying mechanisms of action. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156442. [PMID: 35660597 DOI: 10.1016/j.scitotenv.2022.156442] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Forming calcareous exoskeletons is crucial for the health and survival of calcifiers such as bivalves. However, the impacts of waterborne emergent pollutants on this important process remain largely unknown. In this study, the effects of two types of emergent pollutants, microplastics (MPs) and carbamazepine (CBZ), which are ubiquitously present in ocean environments, on shell formation were assessed in the thick-shell mussel (Mytilus coruscus) with a shell regeneration experiment. In addition, their impacts on the in vivo contents of ATP, Ca2+, carbonic anhydrase (CA), and bone morphogenetic protein receptor type-2 (BMPR2), the activity of phosphofructokinase (PFK) and Ca2+-ATPase, and the expression of shell-formation related genes were analyzed. The data collected demonstrated that shell regeneration after mechanical injury was significantly arrested by CBZ and/or MPs. Besides, all the physiological and molecular parameters investigated were markedly suppressed by these two pollutants. Furthermore, synergistic impacts on most of the parameters examined were observed between CBZ and MPs. Our results indicate that these two pollutants may disrupt shell formation by constraining the availability of raw materials and energy, inhibiting the formation of the organic shell matrix, and interfering with the regulation of crystallization, which may have far-reaching impacts on the health of marine calcifiers.
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Affiliation(s)
- Yihan Yu
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Dandan Tian
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Yu Han
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Lin Huang
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Yu Tang
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Weixia Zhang
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Weishang Zhou
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Wei Shi
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Yingying Yu
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
| | - Guangxu Liu
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China.
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Pang CZ, Ip YK, Chew SF. Ammonia transporter 2 as a molecular marker to elucidate the potentials of ammonia transport in phylotypes of Symbiodinium, Cladocopium and Durusdinium in the fluted giant clam, Tridacna squamosa. Comp Biochem Physiol A Mol Integr Physiol 2022; 269:111225. [PMID: 35460895 DOI: 10.1016/j.cbpa.2022.111225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/17/2022] [Accepted: 04/17/2022] [Indexed: 12/15/2022]
Abstract
Giant clams harbor coccoid Symbiodiniaceae dinoflagellates that are phototrophic. These dinoflagellates generally include multiple phylotypes (species) of Symbiodinium, Cladocopium, and Durusdinium in disparate proportions depending on the environmental conditions. The coccoid symbionts can share photosynthate with the clam host, which in return supply them with nutrients containing inorganic carbon, nitrogen and phosphorus. Symbionts can recycle nitrogen by absorbing and assimilating the endogenous ammonia produced by the host. This study aimed to use the transcript levels of ammonia transporter 2 (AMT2) in Symbiodinium (Symb-AMT2), Cladocopium (Clad-AMT2) and Durusdinium (Duru-AMT2) as molecular indicators to estimate the potential of ammonia transport in these three genera of Symbiodiniaceae dinoflagellates in different organs of the fluted giant clam, Tridacna squamosa, obtained from Vietnam. We also determined the transcript levels of form II ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcII) and nitrate transporter 2 (NRT2) in Symbiodinium (Symb-rbcII; Symb-NRT2), Cladocopium (Clad-rbcII; Clad-NRT2) and Durusdinium (Duru-rbcII; Duru-NRT2), in order to examine the potential of ammonia transport with reference to the potentials of phototrophy or NO3- uptake independent of the quantities and proportion of these Symbiodiniaceae phylotypes. Our results indicated for the first time that phylotypes of Symbiodinium and Cladocopium could have different potentials of ammonia transport, and that phylotypes of Symbiodinium might have higher potential of NO3- transport than ammonia transport. They also suggested that Symbiodiniaceae phylotypes residing in different organs of T. squamosa could have disparate potentials of ammonia transport, alluding to the functional diversity among phylotypes of coccoid Symbiodinium, Cladocopium, and Durusdinium.
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Affiliation(s)
- Caryn Z Pang
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore.
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Armstrong EJ, Watson SA, Stillman JH, Calosi P. Elevated temperature and carbon dioxide levels alter growth rates and shell composition in the fluted giant clam, Tridacna squamosa. Sci Rep 2022; 12:11034. [PMID: 35773289 PMCID: PMC9247080 DOI: 10.1038/s41598-022-14503-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/08/2022] [Indexed: 11/09/2022] Open
Abstract
Giant clams produce massive calcified shells with important biological (e.g., defensive) and ecological (e.g., habitat-forming) properties. Whereas elevated seawater temperature is known to alter giant clam shell structure, no study has examined the effects of a simultaneous increase in seawater temperature and partial pressure of carbon dioxide (pCO2) on shell mineralogical composition in these species. We investigated the effects of 60-days exposure to end-of-the-century projections for seawater temperature (+ 3 °C) and pCO2 (+ 500 µatm) on growth, mineralogy, and organic content of shells and scutes in juvenile Tridacna squamosa giant clams. Elevated temperature had no effect on growth rates or organic content, but did increase shell [24Mg]/[40Ca] as well as [40Ca] in newly-formed scutes. Elevated pCO2 increased shell growth and whole animal mass gain. In addition, we report the first evidence of an effect of elevated pCO2 on element/Ca ratios in giant clam shells, with significantly increased [137Ba]/[40Ca] in newly-formed shells. Simultaneous exposure to both drivers greatly increased inter-individual variation in mineral concentrations and resulted in reduced shell N-content which may signal the onset of physiological stress. Overall, our results indicate a greater influence of pCO2 on shell mineralogy in giant clams than previously recognized.
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Affiliation(s)
- Eric J Armstrong
- Department of Integrative Biology, University of California, 3040 Valley Life Sciences Building #3140, Berkeley, CA, 94720-3140, USA. .,Estuary & Ocean Science Center and Department of Biology, Romberg Tiburon Campus, San Francisco State University, 3150 Paradise Drive, Tiburon, CA, 94920, USA. .,PSL Research University, EPHE, CNRS, Université de Perpignan, Perpignan, France.
| | - Sue-Ann Watson
- Biodiversity and Geosciences Program, Museum of Tropical Queensland, Queensland Museum Network, Townsville, QLD, 4810, Australia.,Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia
| | - Jonathon H Stillman
- Department of Integrative Biology, University of California, 3040 Valley Life Sciences Building #3140, Berkeley, CA, 94720-3140, USA.,Estuary & Ocean Science Center and Department of Biology, Romberg Tiburon Campus, San Francisco State University, 3150 Paradise Drive, Tiburon, CA, 94920, USA
| | - Piero Calosi
- Marine Biology & Ecology Research Center, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK.,Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 Allée Ursulines, Rimouski, QC, G5L 3A1, Canada
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Molecular characterization, immunofluorescent localization, and expression levels of two bicarbonate anion transporters in the whitish mantle of the giant clam, Tridacna squamosa, and the implications for light-enhanced shell formation. Comp Biochem Physiol A Mol Integr Physiol 2022; 268:111200. [PMID: 35337976 DOI: 10.1016/j.cbpa.2022.111200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 11/22/2022]
Abstract
Giant clams conduct light-enhanced shell formation, which requires the increased transport of Ca2+ and inorganic carbon (Ci) from the hemolymph through the shell-facing epithelium of the whitish inner mantle to the extrapallial fluid where CaCO3 deposition occurs. The major form of Ci in the hemolymph is HCO3-, but the mechanisms of HCO3- transport through the basolateral and apical membranes of the shell-facing epithelial cells remain unknown. This study aimed to clone from the inner mantle of Tridacna squamosa the complete coding cDNA sequences of electrogenic Na+-HCO3-cotransporter 1 homolog (NBCe1-like-b) and electrogenic Na+-HCO3-cotransporter 2 homolog (NBCe2-like). NBCe1-like-b comprised 3360 bp, encoding a 125.7 kDa protein with 1119 amino acids. NBCe1-like-b was slightly different from NBCe1-like-a of the ctenidium reported elsewhere, as it had a serine residue (Ser1025), which might undergo phosphorylation leading to the transport of Na+: HCO3- at a ratio of 1: 2 into the cell. NBCe1-like-b was localized at the basolateral membrane of the shell-facing epithelial cells, and its gene and protein expression levels increased significantly in the inner mantle during illumination, indicating a role in the light-enhanced uptake of HCO3- from the hemolymph. The sequence of NBCe2-like obtained from the inner mantle was identical to that reported previously for the outer mantle. In the inner mantle, NBCe2-like had an apical localization in the shell-facing epithelial cells, and its protein abundance was upregulated during illumination. Hence, NBCe2-like might take part in the light-enhanced transport of HCO3- through the apical membrane of these cells into the extrapallial fluid.
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Teng GC, Boo MV, Lam SH, Pang CZ, Chew SF, Ip YK. Molecular characterization and light-dependent expression of glycerol facilitator (GlpF) in coccoid Symbiodiniaceae dinoflagellates of the giant clam Tridacna squamosa. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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The colorful mantle of the giant clam Tridacna squamosa expresses a homolog of electrogenic sodium: Bicarbonate cotransporter 2 that mediates the supply of inorganic carbon to photosynthesizing symbionts. PLoS One 2021; 16:e0258519. [PMID: 34653199 PMCID: PMC8519421 DOI: 10.1371/journal.pone.0258519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/30/2021] [Indexed: 11/19/2022] Open
Abstract
Giant clams live in symbiosis with phototrophic dinoflagellates, which reside extracellularly inside zooxanthellal tubules located mainly in the colourful and extensible outer mantle. As symbiotic dinoflagellates have no access to the ambient seawater, they need to obtain inorganic carbon (Ci) from the host for photosynthesis during illumination. The outer mantle has a host-mediated and light-dependent carbon-concentrating mechanism to augment the supply of Ci to the symbionts during illumination. Iridocytes can increase the secretion of H+ through vacuolar H+-ATPase to dehydrate HCO3− present in the hemolymph to CO2. CO2 can permeate the basolateral membrane of the epithelial cells of the zooxanthellal tubules, and rehydrated back to HCO3− in the cytoplasm catalysed by carbonic anhydrase 2. This study aimed to elucidate the molecular mechanism involved in the transport of HCO3− across the apical membrane of these epithelial cells into the luminal fluid surrounding the symbionts. We had obtained the complete cDNA coding sequence of a homolog of electrogenic Na+-HCO3−cotransporter 2 (NBCe2-like gene) from the outer mantle of the fluted giant clam, Tridacna squamosa. NBCe2-like gene comprised 3,399 bp, encoding a protein of 1,132 amino acids of 127.3 kDa. NBCe2-like protein had an apical localization in the epithelial cells of zooxanthellal tubules, denoting that it could transport HCO3− between the epithelial cells and the luminal fluid. Furthermore, illumination augmented the transcript level and protein abundance of NBCe2-like gene/NBCe2-like protein in the outer mantle, indicating that it could mediate the increased transport of HCO3− into the luminal fluid to support photosynthesis in the symbionts.
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Brahmi C, Chapron L, Le Moullac G, Soyez C, Beliaeff B, Lazareth CE, Gaertner-Mazouni N, Vidal-Dupiol J. Effects of elevated temperature and pCO 2 on the respiration, biomineralization and photophysiology of the giant clam Tridacna maxima. CONSERVATION PHYSIOLOGY 2021; 9:coab041. [PMID: 34150209 PMCID: PMC8208665 DOI: 10.1093/conphys/coab041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/18/2021] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
Many reef organisms, such as the giant clams, are confronted with global change effects. Abnormally high seawater temperatures can lead to mass bleaching events and subsequent mortality, while ocean acidification may impact biomineralization processes. Despite its strong ecological and socio-economic importance, its responses to these threats still need to be explored. We investigated physiological responses of 4-year-old Tridacna maxima to realistic levels of temperature (+1.5°C) and partial pressure of carbon dioxide (pCO2) (+800 μatm of CO2) predicted for 2100 in French Polynesian lagoons during the warmer season. During a 65-day crossed-factorial experiment, individuals were exposed to two temperatures (29.2°C, 30.7°C) and two pCO2 (430 μatm, 1212 μatm) conditions. The impact of each environmental parameter and their potential synergetic effect were evaluated based on respiration, biomineralization and photophysiology. Kinetics of thermal and/or acidification stress were evaluated by performing measurements at different times of exposure (29, 41, 53, 65 days). At 30.7°C, the holobiont O2 production, symbiont photosynthetic yield and density were negatively impacted. High pCO2 had a significant negative effect on shell growth rate, symbiont photosynthetic yield and density. No significant differences of the shell microstructure were observed between control and experimental conditions in the first 29 days; however, modifications (i.e. less-cohesive lamellae) appeared from 41 days in all temperature and pCO2 conditions. No significant synergetic effect was found. Present thermal conditions (29.2°C) appeared to be sufficiently stressful to induce a host acclimatization response. All these observations indicate that temperature and pCO2 are both forcing variables affecting T. maxima's physiology and jeopardize its survival under environmental conditions predicted for the end of this century.
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Affiliation(s)
- Chloé Brahmi
- Univ. Polynésie française, IFREMER, ILM, IRD, EIO UMR 241, F-98702 Faa’a, Tahiti, Polynésie française
| | - Leila Chapron
- School of Earth Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Gilles Le Moullac
- IFREMER, IRD, Institut Louis-Malardé, Univ. Polynésie française, EIO, F-98719 Taravao, Tahiti, Polynésie française, France
| | - Claude Soyez
- IFREMER, IRD, Institut Louis-Malardé, Univ. Polynésie française, EIO, F-98719 Taravao, Tahiti, Polynésie française, France
| | - Benoît Beliaeff
- IFREMER, IRD, Institut Louis-Malardé, Univ. Polynésie française, EIO, F-98719 Taravao, Tahiti, Polynésie française, France
| | - Claire E Lazareth
- Laboratoire de Biologie des Organismes et Ecosystèmes Aquatiques (BOREA) MNHN, CNRS, IRD, SU, UCN, UA, Muséum National d'Histoire Naturelle, 61 Rue Buffon, CP53, 75231, Paris Cedex 05, France
| | - Nabila Gaertner-Mazouni
- Univ. Polynésie française, IFREMER, ILM, IRD, EIO UMR 241, F-98702 Faa’a, Tahiti, Polynésie française
| | - Jeremie Vidal-Dupiol
- IFREMER, IRD, Institut Louis-Malardé, Univ. Polynésie française, EIO, F-98719 Taravao, Tahiti, Polynésie française, France
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan Via Domitia, Montpellier France
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11
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Boo MV, Chew SF, Ip YK. Basolateral Na +/Ca 2+ exchanger 1 and Na +/K +-ATPase, which display light-enhanced gene and protein expression levels, could be involved in the absorption of exogenous Ca 2+ through the ctenidium of the giant clam, Tridacna squamosa. Comp Biochem Physiol A Mol Integr Physiol 2021; 259:110997. [PMID: 34051370 DOI: 10.1016/j.cbpa.2021.110997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/22/2021] [Accepted: 05/24/2021] [Indexed: 10/21/2022]
Abstract
Giant clams perform light-enhanced shell formation (calcification) and therefore need to increase the uptake of exogenous Ca2+ during illumination. The ctenidium of the fluted giant clam, Tridacna squamosa, is involved in light-enhanced Ca2+ uptake. It expresses the pore-forming voltage-gated calcium channel (VGCC) subunit alpha 1 (CACNA1) in the apical membrane of the epithelial cells, and the protein expression level of CACNA1 is upregulated in the ctenidium during illumination. This study aimed to elucidate the mechanism involved in the transport of the absorbed Ca2+ across the basolateral membrane of the ctenidial epithelial cells into the hemolymph. We obtained a homolog of Na+/Ca2+exchanger 1 (NCX1-like) from the ctenidium of T. squamosa, which comprised 2418 bp, encoding a protein of 806 amino acids (88.9 kDa). NCX1-like had a basolateral localization in the epithelial cells of the ctenidial filaments and tertiary water channels. Illumination resulted in significant increases in the transcript and protein levels of NCX1-like/NCX1-like in the ctenidium. Hence, NCX1-like could operate in conjunction with VGCC to increase the transport of Ca2+ from the ambient seawater into the hemolymph during illumination. Illumination also resulted in the upregulation of the gene and protein expression levels of Na+/K+-ATPase (NKA) α-subunit (NKAα/NKAα) in the ctenidium of T. squamosa. As light-enhanced extrusion of Ca2+ into the hemolymph through NCX1-like would lead to a greater influx of extracellular Na+, the increased expression of the basolateral NKA was required to augment the capacity of intracellular Na+ homeostasis.
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Affiliation(s)
- Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.
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12
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Teh LSX, Poo JST, Boo MV, Chew SF, Ip YK. Using glutamine synthetase 1 to evaluate the symbionts' potential of ammonia assimilation and their responses to illumination in five organs of the giant clam, Tridacna squamosa. Comp Biochem Physiol A Mol Integr Physiol 2021; 255:110914. [PMID: 33540079 DOI: 10.1016/j.cbpa.2021.110914] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/23/2021] [Accepted: 01/25/2021] [Indexed: 11/16/2022]
Abstract
Nitrogen-deficient symbiotic dinoflagellates (zooxanthellae) living inside the fluted giant clam, Tridacna squamosa, need to obtain nitrogen from the host. Glutamine synthetase 1 (GS1) is a cytosolic enzyme that assimilates ammonia into glutamine. We determined the transcript levels of zooxanthellal GS1 (Zoox-GS1), which represented comprehensively GS1 transcripts of Symbiodinium, Cladocopium and Durusdinium, in five organs of T. squamosa. The outer mantle had significantly higher transcript level of Zoox-GS1 than the inner mantle, foot muscle, hepatopancreas and ctenidium, but the transcript ratios of Zoox-GS1 to zooxanthellal form II ribulose-1,5-bisphosphate carboxylase/oxygenase (Zoox-rbcII), which represented the potential of ammonia assimilation relative to the phototrophic potential, were comparable among these five organs. Based on transcript ratios of Zoox-GS1 to zooxanthellal Urease (Zoox-URE), the outer mantle had the highest potential of urea degradation relative to ammonia assimilation among the five organs, probably because urea degradation could furnish CO2 and NH3 for photosynthesis and amino acid synthesis, respectively, in the symbionts therein. The protein abundance of Zoox-GS1 was upregulated in the outer mantle and the inner mantle during illumination. Zoox-GS1 could catalyze light-enhanced glutamine formation using ammonia absorbed from the host or ammonia released through urea degradation in the cytoplasm. The glutamine produced could be used to synthesize other nitrogenous compounds, including amino acids in the cytoplasm or in the plastid of the dinoflagellates. Some of the amino acids synthesized by the symbionts in the inner mantle and foot muscle could be donated to the host to support shell organic matrix formation and muscle production, respectively.
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Affiliation(s)
- Leanne S X Teh
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Jeslyn S T Poo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.
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13
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Illumination enhances the protein abundance of sarcoplasmic reticulum Ca 2+-ATPases-like transporter in the ctenidium and whitish inner mantle of the giant clam, Tridacna squamosa, to augment exogenous Ca 2+ uptake and shell formation, respectively. Comp Biochem Physiol A Mol Integr Physiol 2020; 251:110811. [PMID: 33011226 DOI: 10.1016/j.cbpa.2020.110811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/27/2020] [Accepted: 09/27/2020] [Indexed: 02/08/2023]
Abstract
The fluted giant clam, Tridacna squamosa, can perform light-enhanced shell formation, aided by its symbiotic dinoflagellates (Symbiodinium, Cladocopium, Durusdinium), which are able to donate organic nutrients to the host. During light-enhanced shell formation, increased Ca2+ transport from the hemolymph through the shell-facing epithelium of the inner mantle to the extrapallial fluid, where calcification occurs, is necessary. Additionally, there must be increased absorption of exogenous Ca2+ from the surrounding seawater, across the epithelial cells of the ctenidium (gill) into the hemolymph, to supply sufficient Ca2+ for light-enhanced shell formation. When Ca2+ moves across these epithelial cells, the low intracellular Ca2+ concentration must be maintained. Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) regulates the intracellular Ca2+ concentration by pumping Ca2+ into the sarcoplasmic/endoplasmic reticulum (SR/ER) and Golgi apparatus. Indeed, the ctenidium and inner mantle of T. squamosa, expressed a homolog of SERCA (SERCA-like transporter) that consists of 3009 bp, encoding 1002 amino acids of 110.6 kDa. SERCA-like-immunolabeling was non-uniform in the cytoplasm of epithelial cells of ctenidial filaments, and that of the shell-facing epithelial cells of the inner mantle. Importantly, the protein abundance of SERCA-like increased significantly in the ctenidium and the inner mantle of T. squamosa after 12 h and 6 h, respectively, of light exposure. This would increase the capacity of pumping Ca2+ into the endoplasmic reticulum and avert a possible surge in the cytosolic Ca2+ concentration in epithelial cells of the ctenidial filaments during light-enhanced Ca2+ absorption, and in cells of the shell-facing epithelium of the inner mantle during light-enhanced shell formation.
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14
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Chew SF, Koh CZY, Hiong KC, Boo MV, Wong WP, Ip YK. 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. Comp Biochem Physiol A Mol Integr Physiol 2020; 250:110791. [PMID: 32798693 DOI: 10.1016/j.cbpa.2020.110791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/21/2020] [Accepted: 08/07/2020] [Indexed: 01/27/2023]
Abstract
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 O2, 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. It is involved in shell formation, and is shaded from light. CuZnSOD is a cytosolic enzyme that scavenges intracellular O2-. We had obtained from the outer mantle of the fluted giant clam, Tridacna squamosa, the complete cDNA coding sequence of a host-derived copper zinc superoxide dismutase (CuZnSOD), which comprised 462 bp and encoded for 154 amino acids with a calculated MW of 15.6 kDa. CuZnSOD was expressed strongly in the outer mantle, ctenidium, hepatopancreas and kidney. The transcript level of CuZnSOD remained unchanged in the outer mantle during light exposure, but the protein abundance of CuZnSOD increased ~3-fold after exposure to light for 6 or 12 h. By contrast, 12 h of light exposure had no significant effects on the gene and protein expression levels of CuZnSOD/CuZnSOD in the inner mantle. Hence, the increased expression of CuZnSOD in the outer mantle of T. squamosa was probably a host's response to ameliorate oxidative stress related to photosynthesis in the symbionts, and not simply due to increased metabolic rate in the host cells. Evidently, the host clam must possess light- or O2-responsive anti-oxidative defenses in order to align with the light-dependent photosynthetic activity of its symbionts.
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Affiliation(s)
- Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore.
| | - Clarissa Z Y Koh
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Kum C Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
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15
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Sillanpää JK, Cardoso JCDR, Félix RC, Anjos L, Power DM, Sundell K. Dilution of Seawater Affects the Ca 2 + Transport in the Outer Mantle Epithelium of Crassostrea gigas. Front Physiol 2020; 11:1. [PMID: 32038307 PMCID: PMC6987452 DOI: 10.3389/fphys.2020.00001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/01/2020] [Indexed: 12/18/2022] Open
Abstract
Varying salinities of coastal waters are likely to affect the physiology and ion transport capabilities of calcifying marine organisms such as bivalves. To investigate the physiological effect of decreased environmental salinity in bivalves, adult oysters (Crassostrea gigas) were exposed for 14 days to 50% seawater (14) and the effects on mantle ion transport, electrophysiology and the expression of Ca2+ transporters and channels relative to animals maintained in full strength sea water (28) was evaluated. Exposure of oysters to a salinity of 14 decreased the active mantle transepithelial ion transport and specifically affected Ca2+ transfer. Gene expression of the Na+/K+-ATPase and the sarco(endo)plasmic reticulum Ca2+-ATPase was decreased whereas the expression of the T-type voltage-gated Ca channel and the Na+/Ca2+-exchanger increased compared to animals maintained in full SW. The results indicate that decreased environmental salinities will most likely affect not only osmoregulation but also bivalve biomineralization and shell formation.
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Affiliation(s)
- J Kirsikka Sillanpää
- Fish Endocrinology Laboratory, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Joao Carlos Dos Reis Cardoso
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - Rute Castelo Félix
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - Liliana Anjos
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - Deborah Mary Power
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - Kristina Sundell
- Fish Endocrinology Laboratory, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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Cao-Pham AH, Hiong KC, Boo MV, Choo CYL, Wong WP, Chew SF, Ip YK. 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. J Comp Physiol B 2019; 189:693-706. [DOI: 10.1007/s00360-019-01238-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 09/06/2019] [Accepted: 09/23/2019] [Indexed: 12/21/2022]
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17
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Chan CYL, Hiong KC, Choo CYL, Boo MV, Wong WP, Chew SF, Ip YK. Increased apical sodium-dependent glucose transporter abundance in the ctenidium of the giant clam Tridacna squamosa upon illumination. ACTA ACUST UNITED AC 2019; 222:jeb.195644. [PMID: 30877228 DOI: 10.1242/jeb.195644] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/05/2019] [Indexed: 01/14/2023]
Abstract
Giant clams contain phototrophic zooxanthellae, and live in nutrient-deficient tropical waters where light is available. We obtained the complete cDNA coding sequence of a homolog of mammalian sodium/glucose cotransporter 1 (SGLT1) - SGLT1-like - from the ctenidium of the fluted giant clam, Tridacna squamosa SGLT1-like had a host origin and was expressed predominantly in the ctenidium. Molecular characterizations reveal that SGLT1-like of T. squamosa could transport urea, in addition to glucose, as other SGLT1s do. It has an apical localization in the epithelium of ctenidial filaments and water channels, and the apical anti-SGLT1-like immunofluorescence was stronger in individuals exposed to light than to darkness. Furthermore, the protein abundance of SGLT1-like increased significantly in the ctenidium of individuals exposed to light for 12 h, although the SGLT1-like transcript level remained unchanged. As expected, T. squamosa could perform light-enhanced glucose absorption, which was impeded by exogenous urea. These results denote the close relationships between light-enhanced glucose absorption and light-enhanced SGLT1-like expression in the ctenidium of T. squamosa Although glucose absorption could be trivial compared with the donation of photosynthates from zooxanthellae in symbiotic adults, SGLT1-like might be essential for the survival of aposymbiotic larvae, leading to its retention in the symbiotic stage. A priori, glucose uptake through SGLT1-like might be augmented by the surface microbiome through nutrient cycling, and the absorbed glucose could partially fulfill the metabolic needs of the ctenidial cells. Additionally, SGLT1-like could partake in urea absorption, as T. squamosa is known to conduct light-enhanced urea uptake to benefit the nitrogen-deficient zooxanthellae.
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Affiliation(s)
- Christabel Y L Chan
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Kum C Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Celine Y L Choo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore .,The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore 119227, Republic of Singapore
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18
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Cao-Pham AH, Hiong KC, Boo MV, Choo CYL, Pang CZ, Wong WP, Neo ML, Chew SF, Ip YK. Molecular characterization, cellular localization, and light-enhanced expression of Beta-Na +/H + Exchanger-like in the whitish inner mantle of the giant clam, Tridacna squamosa, denote its role in light-enhanced shell formation. Gene 2019; 695:101-112. [PMID: 30763666 DOI: 10.1016/j.gene.2019.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 01/19/2019] [Accepted: 02/01/2019] [Indexed: 12/17/2022]
Abstract
The fluted giant clam, Tridacna squamosa, lives in symbiosis with photosynthetic zooxanthellae, and can engage in light-enhanced growth and shell formation. Light-enhanced shell formation necessitates the elimination of excess H+ from the extrapallial fluid adjacent to the shell. This study aimed to clone Na+/H+Exchanger (NHE) from the whitish inner mantle adjacent to the extrapallial fluid of T. squamosa, to determine its cellular and subcellular localization, and to evaluate the effect of light exposure on its mRNA expression level and protein abundance therein. The complete coding cDNA sequence of NHE obtained was identified as a homolog of beta NHE (βNHE-like). It consisted of 2925 bp, encoding for a polypeptide of 974 amino acids and 107.1 kDa, and was expressed predominantly in the inner mantle. There, βNHE-like was localized in the apical membrane of the seawater-facing epithelium by immunofluorescence microscopy. After exposure to light for 12 h, the seawater-facing epithelium of the inner mantle displayed consistently stronger immunostaining than that of the control exposed to 12 h of darkness. Western blotting confirmed that light exposure significantly enhanced the protein abundance of βNHE-like in the inner mantle. These results denote that some of the excess H+ generated during light-enhanced shell formation can be excreted through the light-dependent βNHE-like of the seawater-facing epithelium to minimize the impact on the whole-body pH. Importantly, the excreted H+ could dehydrate exogenous HCO3-, and facilitate the absorption of inorganic carbon through the seawater-facing epithelium dedicated for light-enhanced shell formation due to its close proximity with the shell-facing epithelium. NUCLEOTIDE SYMBOL COMBINATIONS: Pairs: R = A/G; W = A/T; Y = C/T. Triples: D = A/G/T.
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Affiliation(s)
- Anh H Cao-Pham
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Kum C Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Celine Y L Choo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Caryn Z Pang
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Mei L Neo
- St. John's Island National Marine Laboratory, National University of Singapore, 18 Kent Ridge Road, Singapore 119227, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore; The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore 119227, Republic of Singapore.
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19
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Sillanpää JK, Sundh H, Sundell KS. Calcium transfer across the outer mantle epithelium in the Pacific oyster, Crassostrea gigas. Proc Biol Sci 2018; 285:20181676. [PMID: 30429301 PMCID: PMC6253367 DOI: 10.1098/rspb.2018.1676] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/24/2018] [Indexed: 11/12/2022] Open
Abstract
Calcium transport is essential for bivalves to be able to build and maintain their shells. Ionized calcium (Ca2+) is taken up from the environment and eventually transported through the outer mantle epithelium (OME) to the shell growth area. However, the mechanisms behind this process are poorly understood. The objective of the present study was to characterize the Ca2+ transfer performed by the OME of the Pacific oyster, Crassostrea gigas, as well as to develop an Ussing chamber technique for the functional assessment of transport activities in epithelia of marine bivalves. Kinetic studies revealed that the Ca2+ transfer across the OME consists of one saturable and one linear component, of which the saturable component fits best to Michaelis-Menten kinetics and is characterized by a Km of 6.2 mM and a Vmax of 3.3 nM min-1 The transcellular transfer of Ca2+ accounts for approximately 60% of the total Ca2+ transfer across the OME of C. gigas at environmental Ca2+ concentrations. The use of the pharmacological inhibitors: verapamil, ouabain and caloxin 1a1 revealed that voltage-gated Ca2+-channels, plasma-membrane Ca2+-ATPase and Na+/Ca2+-exchanger all participate in the transcellular Ca2+ transfer across the OME and a model for this Ca2+ transfer is presented and discussed.
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Affiliation(s)
- J Kirsikka Sillanpää
- Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden
| | - Henrik Sundh
- Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden
| | - Kristina S Sundell
- Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden
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20
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Light-enhanced expression of Carbonic Anhydrase 4-like supports shell formation in the fluted giant clam Tridacna squamosa. Gene 2018; 683:101-112. [PMID: 30316924 DOI: 10.1016/j.gene.2018.10.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/25/2018] [Accepted: 10/09/2018] [Indexed: 12/11/2022]
Abstract
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 (Ci) to support photosynthesis in the symbionts and light-enhanced calcification in the host. In this study, we cloned and characterized a host Carbonic Anhydrase 4 homolog (CA4-like) from the whitish inner mantle of the giant clam Tridacna squamosa. The full cDNA coding sequence of CA4-like consisted of 1002 bp, encoding for 334 amino acids of 38.5 kDa. The host CA4-like was phenogramically distinct from algal CAs. The transcript level of CA4-like in the inner mantle was ~3-fold higher than those in the colorful outer mantle and the ctenidium. In the inner mantle, CA4-like was immunolocalized in the apical membrane of the seawater-facing epithelial cells, but absent from the shell-facing epithelium. Hence, CA4-like was positioned to catalyze the conversion of HCO3- to CO2 in the ambient seawater which would facilitate CO2 uptake. The absorbed CO2 could be converted back to HCO3- by the cytoplasmic CA2-like. As the protein abundance of CA4-like increased in the inner mantle after 6 or 12 h of light exposure, there could be an augmentation of the total CA4-like activity to increase Ci uptake in light. It is plausible that the absorbed Ci was allocated preferentially for shell formation due to the close proximity of the seawater-facing epithelium to the shell-facing epithelium in the inner mantle that contains only few zooxanthellae.
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21
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Ip YK, Hiong KC, Lim LJ, Choo CY, Boo MV, Wong WP, Neo ML, Chew SF. Molecular characterization, light-dependent expression, and cellular localization of a host vacuolar-type H + -ATPase (VHA) subunit A in the giant clam, Tridacna squamosa , indicate the involvement of the host VHA in the uptake of inorganic carbon and its supply to the symbiotic zooxanthellae. Gene 2018; 659:137-148. [DOI: 10.1016/j.gene.2018.03.054] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 03/13/2018] [Accepted: 03/16/2018] [Indexed: 10/17/2022]
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22
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Boo MV, Hiong KC, Goh EJK, Choo CYL, Wong WP, Chew SF, Ip YK. 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. J Comp Physiol B 2018; 188:765-777. [DOI: 10.1007/s00360-018-1161-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 04/03/2018] [Accepted: 04/15/2018] [Indexed: 01/31/2023]
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23
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Chan CYL, Hiong KC, Boo MV, Choo CYL, Wong WP, Chew SF, Ip YK. Light exposure enhances urea absorption in the fluted giant clam, Tridacna squamosa, and up-regulates the protein abundance of a light-dependent urea active transporter, DUR3-like, in its ctenidium. J Exp Biol 2018; 221:jeb176313. [PMID: 29540461 DOI: 10.1242/jeb.176313] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/12/2018] [Indexed: 12/26/2022]
Abstract
Giant clams live in nutrient-poor reef waters of the Indo-Pacific and rely on symbiotic dinoflagellates (Symbiodinium spp., also known as zooxanthellae) for nutrients. As the symbionts are nitrogen deficient, the host clam has to absorb exogenous nitrogen and supply it to them. This study aimed to demonstrate light-enhanced urea absorption in the fluted giant clam, Tridacna squamosa, and to clone and characterize the urea active transporter DUR3-like from its ctenidium (gill). The results indicate that T. squamosa absorbs exogenous urea, and the rate of urea uptake in the light was significantly higher than that in darkness. The DUR3-like coding sequence obtained from its ctenidium comprised 2346 bp, encoding a protein of 782 amino acids and 87.0 kDa. DUR3-like was expressed strongly in the ctenidium, outer mantle and kidney. Twelve hours of exposure to light had no significant effect on the transcript level of ctenidial DUR3-like However, between 3 and 12 h of light exposure, DUR3-like protein abundance increased progressively in the ctenidium, and became significantly greater than that in the control at 12 h. DUR3-like had an apical localization in the epithelia of the ctenidial filaments and tertiary water channels. Taken together, these results indicate that DUR3-like might participate in light-enhanced urea absorption in the ctenidium of T. squamosa When made available to the symbiotic zooxanthellae that are known to possess urease, the absorbed urea can be metabolized to NH3 and CO2 to support amino acid synthesis and photosynthesis, respectively, during insolation.
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Affiliation(s)
- Christabel Y L Chan
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Kum C Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Celine Y L Choo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
- The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore 119227, Republic of Singapore
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24
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Koh CZY, Hiong KC, Choo CYL, Boo MV, Wong WP, Chew SF, Neo ML, Ip YK. Molecular Characterization of a Dual Domain Carbonic Anhydrase From the Ctenidium of the Giant Clam, Tridacna squamosa, and Its Expression Levels After Light Exposure, Cellular Localization, and Possible Role in the Uptake of Exogenous Inorganic Carbon. Front Physiol 2018; 9:281. [PMID: 29632495 PMCID: PMC5879104 DOI: 10.3389/fphys.2018.00281] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 03/09/2018] [Indexed: 12/19/2022] Open
Abstract
A Dual-Domain Carbonic Anhydrase (DDCA) had been sequenced and characterized from the ctenidia (gills) of the giant clam, Tridacna squamosa, which lives in symbiosis with zooxanthellae. DDCA was expressed predominantly in the ctenidium. The complete cDNA coding sequence of DDCA from T. squamosa comprised 1,803 bp, encoding a protein of 601 amino acids and 66.7 kDa. The deduced DDCA sequence contained two distinct α-CA domains, each with a specific catalytic site. It had a high sequence similarity with tgCA from Tridacna gigas. In T. squamosa, the DDCA was localized apically in certain epithelial cells near the base of the ctenidial filament and the epithelial cells surrounding the tertiary water channels. Due to the presence of two transmembrane regions in the DDCA, one of the Zn2+-containing active sites could be located externally and the other one inside the cell. These results denote that the ctenidial DDCA was positioned to dehydrate [Formula: see text] to CO2 in seawater, and to hydrate the CO2 that had permeated the apical membrane back to [Formula: see text] in the cytoplasm. During insolation, the host clam needs to increase the uptake of inorganic carbon from the ambient seawater to benefit the symbiotic zooxanthellae; only then, can the symbionts conduct photosynthesis and share the photosynthates with the host. Indeed, the transcript and protein levels of DDCA/DDCA in the ctenidium of T. squamosa increased significantly after 6 and 12 h of exposure to light, respectively, denoting that DDCA could participate in the light-enhanced uptake and assimilation of exogenous inorganic carbon.
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Affiliation(s)
- Clarissa Z. Y. Koh
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Celine Y. L. Choo
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Mel V. Boo
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, Singapore
| | - Mei L. Neo
- St. John's Island National Marine Laboratory, National University of Singapore, Singapore, Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- The Tropical Marine Science Institute, National University of Singapore, Singapore, Singapore
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25
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Boo MV, Hiong KC, Choo CYL, Cao-Pham AH, Wong WP, Chew SF, Ip YK. The inner mantle of the giant clam, Tridacna squamosa, expresses a basolateral Na+/K+-ATPase α-subunit, which displays light-dependent gene and protein expression along the shell-facing epithelium. PLoS One 2017; 12:e0186865. [PMID: 29049367 PMCID: PMC5648256 DOI: 10.1371/journal.pone.0186865] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 10/09/2017] [Indexed: 12/11/2022] Open
Abstract
Na+/K+-ATPase (NKA) is essential for maintaining the Na+ and K+ gradients, and supporting the secondary active transport of certain ions/molecules, across the plasma membrane of animal cells. This study aimed to clone the NKA α-subunit (NKAα) from the inner mantle adjacent to the extrapallial fluid of Tridacna squamosa, to determine its subcellular localization, and to examine the effects of light exposure on its transcript level and protein abundance. The cDNA coding sequence of NKAα from T. squamosa comprised 3105 bp, encoding 1034 amino acids with an estimated molecular mass of 114 kDa. NKAα had a basolateral localization along the shell-facing epithelium of the inner mantle. Exposure to 12 h of light led to a significantly stronger basolateral NKAα-immunofluorescence at the shell-facing epithelium, indicating that NKA might play a role in light-enhanced calcification in T. squamosa. After 3 h of light exposure, the transcript level of NKAα decreased transiently in the inner mantle, but returned to the control level thereafter. In comparison, the protein abundance of NKAα remained unchanged at hour 3, but became significantly higher than the control after 12 h of light exposure. Hence, the expression of NKAα in the inner mantle of T. squamosa was light-dependent. It is probable that a higher expression level of NKA was needed in the shell-facing epithelial cells of the inner mantle to cope with a rise in Na+ influx, possibly caused by increases in activities of some Na+-dependent ion transporters/channels involved in light-enhanced calcification.
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Affiliation(s)
- Mel V. Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore
| | - Celine Y. L. Choo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore
| | - Anh H. Cao-Pham
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, Republic of Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore
- The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore
- * E-mail:
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