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Rahman MF, Billah MM, Kline RJ, Rahman MS. Effects of elevated temperature on 8-OHdG expression in the American oyster ( Crassostrea virginica): Induction of oxidative stress biomarkers, cellular apoptosis, DNA damage and γH2AX signaling pathways. Fish Shellfish Immunol Rep 2022; 4:100079. [PMID: 36589260 PMCID: PMC9798191 DOI: 10.1016/j.fsirep.2022.100079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/10/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Global temperature is increasing due to anthropogenic activities and the effects of elevated temperature on DNA lesions are not well documented in marine organisms. The American oyster (Crassostrea virginica, an edible and commercially important marine mollusk) is an ideal shellfish species to study oxidative DNA lesions during heat stress. In this study, we examined the effects of elevated temperatures (24, 28, and 32 °C for one-week exposure) on heat shock protein-70 (HSP70, a biomarker of heat stress), 8‑hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of pro-mutagenic DNA lesion), double-stranded DNA (dsDNA), γ-histone family member X (γH2AX, a molecular biomarker of DNA damage), caspase-3 (CAS-3, a key enzyme of apoptotic pathway) and Bcl-2-associated X (BAX, an apoptosis regulator) protein and/or mRNA expressions in the gills of American oysters. Immunohistochemical and qRT-PCR results showed that HSP70, 8-OHdG, dsDNA, and γH2AX expressions in gills were significantly increased at high temperatures (28 and 32 °C) compared with control (24°C). In situ TUNEL analysis showed that the apoptotic cells in gill tissues were increased in heat-exposed oysters. Interestingly, the enhanced apoptotic cells were associated with increased CAS-3 and BAX mRNA and/or protein expressions, along with 8-OHdG levels in gills after heat exposure. Moreover, the extrapallial (EP) fluid (i.e., extracellular body fluid) protein concentrations were lower; however, the EP glucose levels were higher in heat-exposed oysters. Taken together, these results suggest that heat shock-driven oxidative stress alters extracellular body fluid conditions and induces cellular apoptosis and DNA damage, which may lead to increased 8-OHdG levels in cells/tissues in oysters.
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Key Words
- 8-OHdG, 8‑hydroxy-2′-deoxyguanosine
- BAX, bcl-2-associate X
- BSA, bovine serum albumin
- CAS-3, caspase-3
- Caspase 3
- DSBs, double-stranded breaks
- EP, extrapallial
- Extrapallial fluid
- HSP70
- HSP70, heat shock protein 70
- Heat stress
- Marine mollusks
- PBS, Phosphate buffer saline
- SSBs, single-stranded breaks
- TUNEL, terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling
- dsDNA breaks
- dsDNA, double-stranded DNA
- qRT-PCR, quantitative real-time polymerase chain reaction
- ssDNA, single-stranded DNA
- γ-H2AX, γ-histone family member X
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Affiliation(s)
- Md Faizur Rahman
- School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Brownsville, TX, USA
| | - Mohammad Maruf Billah
- School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Brownsville, TX, USA
| | - Richard J. Kline
- School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Brownsville, TX, USA,Department of Biology, University of Texas Rio Grande Valley, Brownsville, TX, USA
| | - Md Saydur Rahman
- School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Brownsville, TX, USA,Department of Biology, University of Texas Rio Grande Valley, Brownsville, TX, USA,Corresponding author at: Department of Biology, University of Texas Rio Grande Valley, 1 West University Blvd., Brownsville, Texas 78520, USA.
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Boo MV, Pang CZ, Chew SF, Ip YK. 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] [What about the content of this article? (0)] [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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Allam B, Pales Espinosa E, Tanguy A, Jeffroy F, Le Bris C, Paillard C. Transcriptional changes in Manila clam (Ruditapes philippinarum) in response to Brown Ring Disease. Fish Shellfish Immunol 2014; 41:2-11. [PMID: 24882017 DOI: 10.1016/j.fsi.2014.05.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/12/2014] [Accepted: 05/15/2014] [Indexed: 02/05/2023]
Abstract
Brown Ring Disease (BRD) is a bacterial infection affecting the economically-important clam Ruditapes philippinarum. The disease is caused by a bacterium, Vibrio tapetis, that colonizes the edge of the mantle, altering the biomineralization process and normal shell growth. Altered organic shell matrices accumulate on the inner face of the shell leading to the formation of the typical brown ring in the extrapallial space (between the mantle and the shell). Even though structural and functional changes have been described in solid (mantle) and fluid (hemolymph and extrapallial fluids) tissues from infected clams, the underlying molecular alterations and responses remain largely unknown. This study was designed to gather information on clam molecular responses to the disease and to compare focal responses at the site of the infection (mantle and extrapallial fluid) with systemic (hemolymph) responses. To do so, we designed and produced a Manila clam expression oligoarray (15K Agilent) using transcriptomic data available in public databases and used this platform to comparatively assess transcriptomic changes in mantle, hemolymph and extrapallial fluid of infected clams. Results showed significant regulation in diseased clams of molecules involved in pathogen recognition (e.g. lectins, C1q domain-containing proteins) and killing (defensin), apoptosis regulation (death-associated protein, bcl-2) and in biomineralization (shell matrix proteins, perlucin, galaxin, chitin- and calcium-binding proteins). While most changes in response to the disease were tissue-specific, systemic alterations included co-regulation in all 3 tested tissues of molecules involved in microbe recognition and killing (complement-related factors, defensin). These results provide a first glance at molecular alterations and responses caused by BRD and identify targets for future functional investigations.
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Affiliation(s)
- Bassem Allam
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, USA.
| | | | - Arnaud Tanguy
- Station Biologique de Roscoff, UPMC-CNRS, Roscoff, France
| | - Fanny Jeffroy
- Institut Universitaire Européen de la Mer, Plouzané, France
| | - Cedric Le Bris
- Institut Universitaire Européen de la Mer, Plouzané, France
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