| 1. |
- Hu, M., et al.
(författare)
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Effect of pH and temperature on antioxidant responses of the thick shell mussel Mytilus coruscus
- 2015
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Ingår i: Fish and Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 46:2, s. 573-583
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the combined effects of seawater pH decrease and temperature increase on the activity of antioxidant enzymes in the thick shell mussel Mytilus coruscus, an ecological and economic bivalve species widely distributed along the East China Sea. Mussels were exposed to three pH levels (8.1, 7.7 and 7.3) and two temperatures (25 °C and 30 °C) for 14 days. Activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione (GSH), acid phosphatase (ACP), alkaline phosphatase (AKP) and glutamic-pyruvic transaminase (GPT) were measured in gills and digestive glands after 1, 3, 7 and 14 days of exposure. All enzymatic activities were significantly impacted by pH, temperature. Enzymatic activities at the high temperature were significantly higher than those at the low temperature, and the mussels exposed to pH 7.3 showed significantly higher activities than those under higher pH condition for all enzymes except ACP. There was no interaction between temperature and pH in two third of the measured activities suggesting similar mode of action for both drivers. Interaction was only consistently significant for GPX. PCA revealed positive relationships between the measured biochemical indicators in both gills and digestive glands. Overall, our results suggest that decreased pH and increased temperature induce a similar anti-oxidative response in the thick shell mussel. © 2015 Elsevier Ltd.
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| 2. |
- Hu, M., et al.
(författare)
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Variability in larval gut pH regulation defines sensitivity to ocean acidification in six species of the ambulacraria superphylum
- 2017
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 284:1864
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Tidskriftsartikel (refereegranskat)abstract
- The unusual rate and extent of environmental changes due to human activities may exceed the capacity of marine organisms to deal with this phenomenon. The identification of physiological systems that set the tolerance limits and their potential for phenotypic buffering in the most vulnerable ontogenetic stages become increasingly important to make large-scale projections. Here, we demonstrate that the differential sensitivity of non-calcifyingAmbulacraria (echinoderms and hemichordates) larvae towards simulated ocean acidification is dictated by the physiology of their digestive systems. Gastric pH regulation upon experimental ocean acidification was compared in six species of the superphylum Ambulacraria.We observed a strong correlation between sensitivity to ocean acidification and the ability to regulate gut pH. Surprisingly, species with tightly regulated gastric pH were more sensitive to ocean acidification. This study provides evidence that strict maintenance of highly alkaline conditions in the larval gut of Ambulacraria early life stages may dictate their sensitivity to decreases in seawater pH. These findings highlight the importance of identifying and understanding pH regulatory systems in marine larval stages that may contribute to substantial energetic challenges under near-future ocean acidification scenarios. © 2017 The Author(s) Published by the Royal Society. All rights reserved.
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| 3. |
- Hu, M. Y., et al.
(författare)
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Temperature Modulates the Effects of Ocean Acidification on Intestinal Ion Transport in Atlantic Cod, Gadus morhua
- 2016
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- CO2-driven seawater acidification has been demonstrated to enhance intestinal bicarbonate secretion rates in teleosts, leading to an increased release of CaCO3 under simulated ocean acidification scenarios. In this study, we investigated if increasing CO2 levels stimulate the intestinal acid-base regulatory machinery of Atlantic cod (Gadus morhua) and whether temperatures at the upper limit of thermal tolerance stimulate or counteract ion regulatory capacities. Juvenile G. morhua were acclimated for 4 weeks to three CO2 levels (550, 1200, and 2200 mu atm) covering present and near-future natural variability, at optimum (10 degrees C) and summer maximum temperature (18 degrees C), respectively. Immunohistochemical analyses revealed the subcellular localization of ion transporters, including Na+/K+-ATPase (NKA), Na+/H+-exchanger 3 (NHE3), Na+/HCO3- cotransporter (NBC1), pendrin-like C1(-)/HCO3- exchanger (SLC26a6), V-type H+-KATPase subunit a (VHA), and Cl- channel 3 (CLC3) in epithelial cells of the anterior intestine. At 10 degrees C, proteins and mRNA were generally up-regulated for most transporters in the intestinal epithelium after acclimation to higher CO2 levels. This supports recent findings demonstrating increased intestinal HCO3- secretion rates in response to CO2 induced seawater acidification. At 18 degrees C, mRNA expression and protein concentrations of most ion transporters remained unchanged or were even decreased, suggesting thermal compensation. This response may be energetically favorable to retain blood HCO3- levels to stabilize pH(e), but may negatively affect intestinal salt and water resorption of marine teleosts in future oceans.
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| 4. |
- Huang, X., et al.
(författare)
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Impact of zinc oxide nanoparticles and ocean acidification on antioxidant responses of Mytilus coruscus
- 2018
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535. ; 196, s. 182-195
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Tidskriftsartikel (refereegranskat)abstract
- Increased production of engineered nanoparticles (NPs) has raised extensive concerns about the potential toxic effects on marine organisms. Extensive evidences documented the impact of ocean acidification (OA) on the physiology and fitness of bivalves. In the present study, we investigated the biochemical responses of the mussel Mytilus coruscus exposed to both nano-ZnO and low pH relevant for ocean acidification conditions for 14 d followed by a 7-d recovery period. Most biochemical indexes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), acid phosphatase (ACP) and alkaline phosphatase (ALP)) measured in gills and hemocytes were increased when the mussels were subject to low pH or high concentration of nano-ZnO, suggesting oxidative stress responses. No significant interactions between the two stressors were observed for most measured parameters. After a 1 week recovery period, low pH and nano-ZnO had less marked impact for SOD, GPx, ACP and ALP in hemocytes as compared to the end of the 14 d exposure. However, no recovery was observed in gills. Overall, our results suggest that both low pH and nano-ZnO induce an anti-oxidative response in Mytilus coruscus with gills being more sensitive than hemocytes. © 2017
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| 5. |
- Huang, X. Z., et al.
(författare)
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Effects of copper on hemocyte parameters in the estuarine oyster Crassostrea rivularis under low pH conditions
- 2018
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X. ; 203, s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- With the development of industry and agriculture, the metal pollutants (e.g., Cu) are inevitably released into the aquatic environment. In addition, ocean acidification (OA) as a major environmental stress is affecting marine organisms. In this study, we investigated the hemocyte responses of the estuarine oyster Crassostrea rivularis exposed to six combinations of two pH levels (8.1 and 7.7) and three Cu concentrations (0, 10 and 50 mu g/l) using flow cytometry in vitro and in vivo. In both experiments, Cu and low pH jointly affected the hemocyte parameters of oyster. High Cu exposure resulted in decreased total hemocyte count (THC), esterase activity (EA) and lysosomal content (LC) and increased hemocyte mortality (HM), phagocytosis activity (PA) and reactive oxygen species (ROS) production, especially under low pH conditions. The immune suppression of metal-exposure was more significant than low pH exposure with a 28-d experimental period in oysters. A slight recovery of the immune parameters was observed in THC, HM, PA, ROS and LC. During the depuration period, the modulatory effects of pH were still obvious. In addition, carry-over effects of high Cu and low pH were still observed. Overall, our results showed that copper and low pH weaken immune functions of hemocyte in oysters, with synergistic effects. This work provides new evidence of sublethal negative effects of metals on marine animals under global change scenarios, and copper likely leads to reduced fitness of oysters under low pH conditions.
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| 6. |
- Huang, X. Z., et al.
(författare)
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Oxidative stress induced by titanium dioxide nanoparticles increases under seawater acidification in the thick shell mussel Mytilus coruscus
- 2018
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Ingår i: Marine Environmental Research. - 0141-1136. ; 137, s. 49-59
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Tidskriftsartikel (refereegranskat)abstract
- Biochemical responses of the mussel Mytflrn coruscus exposed to different concentrations of titanium dioxide nanoparticles (nano-Ti0(2)) (0, 2.5, 10mgL(-1)) and two pH levels (pH 8.1 and pH 7.3) for 14 days. Mussel responses were also investigated after a 7 days recovery period (pH 8.1 and no nanoparticle). Exposure to nanoTi0(2) led changes in antioxidant indexes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH)), biotransformation enzyme activity (GST) and malondialdehyde level (MDA) in gills and digestive glands. An increase in MDA level and a decrease in SOD and GSH activities were observed in gill of mussels exposed to 10 mg L-n1 nano-TiO2. This effect was more severe in mussels kept at pH 7.3 as compared to pH 8.1. A different response was observed in the digestive gland as SOD, CAT and GSH levels increased in mussels exposed to nano-TiO2. These contrasting results in digestive glands and gills were only evident at high concentration of nano-TiO2 and low pH. A 7 days recovery period was not sufficient to fully restore SOD, GPx, GST, GSH and MDA levels to levels before exposure to nano-TiO2 and low pH. Overall, our results confirmed that seawater acidification modulates effects of nanoparticles in mussels, and that gills are more sensitive to these stressors as compared with digestive glands.
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| 7. |
- Khan, F. U., et al.
(författare)
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Antioxidant responses of the mussel Mytilus coruscus co-exposed to ocean acidification, hypoxia and warming
- 2021
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X. ; 162:January
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, the combined effects of pH, dissolved oxygen (DO) and temperature levels on the antioxidant responses of the mussel Mytilus coruscus were evaluated. Mussels were exposed to two pH (8.1, 7.7-acidification), two DO (6 mg L−1, 2 mg L−1-hypoxia) and two temperature levels (20 °C, 30 °C-warming) for 30 days. SOD, CAT, MDA, GPx, GSH, GST, TAOC, AKP, ACP, GPT, AST levels were measured in the gills of mussels. All tested biochemical parameters were altered by these three environmental stressors. Values for all the test parameters except GSH first increased and then decreased at various experimental treatments during days 15 and 30 as a result of acidification, hypoxia and warming. GSH content always increased with decreased pH, decreased DO and increased temperature. PCA showed a positive correlation among all the measured biochemical indexes. IBR results showed that M. coruscus were adversely affected by reduced pH, low DO and elevated temperature. © 2020 Elsevier Ltd
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| 8. |
- Shang, Y. Y., et al.
(författare)
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Sex-specific digestive performance of mussels exposed to warming and starvation
- 2022
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- As global climate change has dramatically impacted the ocean, severe temperature elevation and a decline in primary productivity has frequently occurred, which has affected the structure of coastal biomes. In this study, the sex-specific responses to temperature change and food availability in mussels were determined in terms of digestive performance. The thick-shelled mussels Mytilus coruscus (male and female) were exposed to different temperature and nutritional conditions for 30 days. The results showed that the digestive enzymes of mussels were significantly affected by temperature, food, sex, and their interactions. High temperature (30 & DEG;C) and starvation significantly decreased amylase, lysozyme, and pepsase activities of female mussels, while trypsin and trehalase did not change significantly at the experimental end. The activity of amylase, trypsin, and trehalase was significantly reduced in males at high temperature (30 & DEG;C) under starvation treatment, but high temperature (30 & DEG;C) elevated pepsase. Unsurprisingly, starvation caused the reduction of lysozyme and pepsase under 25 & DEG;C in males. Amylase, lipase, and trehalase were higher in female mussels compared with males, while the enzymatic activities of lysozyme, pepsase, and trypsin were higher in male mussels than females. Principal component analysis showed that different enzyme activity indexes were separated in male and female mussels, indicating that male and female mussels exhibited significantly different digestive abilities under temperature and food condition change. The study clarified sex-specific response difference in mussel digestive enzymes under warming and starvation and provided guidance for the development of mussel aquaculture (high temperature management and feeding strategy) under changing marine environments.
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| 9. |
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| 10. |
- Sui, Y., et al.
(författare)
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Combined effects of short-term exposure to elevated CO2 and decreased O2 on the physiology and energy budget of the thick shell mussel Mytilus coruscus
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535. ; 155, s. 207-216
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxia and ocean acidification are two consequences of anthropogenic activities. These global trends occur on top of natural variability. In environments such as estuarine areas, short-term acute pH and O2 fluctuations are occurring simultaneously. The present study tested the combined effects of short-term seawater acidification and hypoxia on the physiology and energy budget of the thick shell mussel Mytilus coruscus. Mussels were exposed for 72 h to six combined treatments with three pH levels (8.1, 7.7 and 7.3) and two dissolved oxygen (DO) levels (2 mg L-1, 6 mg L-1). Clearance rate (CR), food absorption efficiency (AE), respiration rate (RR), ammonium excretion rate (ER), O:N ratio and scope for growth (SFG) were significantly reduced, and faecal organic dry weight ratio (E) was significantly increased at low DO. Low pH did not lead to a reduced SFG. Interactive effects of pH and DO were observed for CR, E and RR. Principal component analysis (PCA) revealed positive relationships among most physiological indicators, especially between SFG and CR under normal DO conditions. These results demonstrate that Mytilus coruscus was sensitive to short-term (72 h) exposure to decreased O2 especially if combined with decreased pH levels. In conclusion, the short-term oxygen and pH variation significantly induced physiological changes of mussels with some interactive effects. © 2016 Elsevier Ltd.
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