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Effect of silver nanoparticles on gill membranes of common carp: Modification of fatty acid profile, lipid peroxidation and membrane fluidity
2020
Xiang, Qian-Qian | Wang, Di | Zhang, Ji-Lai | Ding, Cheng-Zhi | Luo, Xia | Tao, Juan | Ling, Jian | Shea, Damian | Chen, Li-Qiang
Although the toxicity of silver nanoparticles (AgNPs) in aquatic organisms has been extensively investigated, the mechanism by which AgNPs damage membranes remains unclear. This study investigated the toxic effects of a series of sub-lethal concentrations of AgNPs on the membranes of freshwater carp (Cyprinus carpio) gills, based on changes in membrane fatty acid (FA) profile, membrane fluidity, membrane lipid peroxidation, and histopathology. Most of the FAs in fish gill membrane was not significantly affected by exposure to multiple AgNPs concentrations, only few significant changes occurred in some specific FAs species at a high concentration of AgNPs exposure. In particular, high concentrations of AgNPs significantly decreased the proportions of two important long-chain n-3 series polyunsaturated FAs (C20: 5n3, and C22: 6n3), resulting in a decreased ratio of n-3 polyunsaturated FAs to n-6 polyunsaturated FAs (Σn-3UFA/Σn-6UFA). The AgNPs also caused a dose-dependent decrease in fish gill membrane fluidity, increased the level of lipid peroxidation, and inhibited Na+/K+-ATPase enzyme activity. Further histopathological examination revealed that exposure to AgNPs can cause toxic responses in the lamellae, including the thinning of the basement membrane, malformation, and inflammation. Together, the results suggest that the mechanism of AgNPs membrane toxicity involves the oxidization of long-chain omega-3 unsaturated FAs to saturated FAs via lipid peroxidation, resulting in, decreased membrane fluidity and ultimately the destruction of the normal physiological function of the fish gill membrane. The findings contribute significantly to our understanding of nanoparticle-induced membrane toxicity and potential risks in aquatic environments.
Show more [+] Less [-]A preliminary analysis of microplastics in edible versus non-edible tissues from seafood samples
2020
Akoueson, Fleurine | Sheldon, Lisa M. | Danopoulos, Evangelos | Morris, Steve | Hotten, Jessica | Chapman, Emma | Li, Jiana | Rotchell, Jeanette M.
Plastics have been widely reported to be present in the environment yet there are still many questions regarding the extent of this and the impacts these may have on both the environment and human health. The purpose of this investigation is to determine levels of micro and mesoplastic (MP), in the 1–5000 μm range, in commercially important species of finfish and shellfish. Additionally, to determine and compare the relative MP levels in edible versus non-edible tissues, and consider the wider implications in terms of human health concerns with a preliminary risk identification approach. For several fish species, samples taken from typically non-edible (gills, digestive system) and edible (muscle) flesh, and were analysed separately. Scallops, where all tissues are edible, were analysed whole. Significant differences were observed in the number of particles isolated from the finfish gills and digestive tissues relative to the control samples, but not in the edible flesh. For scallops, the abundance of particles in the Scottish samples did not vary significantly from the control, while the Patagonian scallops displayed significantly higher numbers of MPs. Characterisation of MPs by FTIR microscopy found that 16–60% (depending on species) were polyethylene terephthalate (PET) and polyethylene (PE) in origin. The risk identification results validate MPs as an emerging risk in the food chain and establish seafood as a vector for the exposure and uptake of MPs through the ingestion route for humans. Levels of MPs in seafood, and a direct link to the human food chain, suggests that their quantification be included as one food safety measure.
Show more [+] Less [-]Role of prey subcellular distribution on the bioaccumulation of yttrium (Y) in the rainbow trout
2020
Cardon, Pierre-Yves | Roques, Olivier | Caron, Antoine | Rosabal, Maikel | Fortin, Claude | Amyot, Marc
Our knowledge of the processes leading to the bioaccumulation of rare earth elements (REE) in aquatic biota is limited. As the contamination of freshwater ecosystems by anthropogenic REE have recently been reported, it becomes increasingly urgent to understand how these metals are transferred to freshwater organisms in order to develop appropriate guidelines. We exposed rainbow trout (Oncorhynchus mykiss) to an REE, yttrium (Y), to either a range of Y-contaminated prey (Daphnia magna) or a range of Y-contaminated water. For the feeding experiment, the relationship between the Y assimilation by O. mykiss and the Y subcellular fractionation in D. magna was evaluated. Assimilation efficiency of Y by O. mykiss was low, ranging from 0.8 to 3%. These values were close to the proportion of Y accumulated in D. magna cytosol, 0.6–2%, a theoretical trophically available fraction. Moreover, under our laboratory conditions, water appeared as a poor source of Y transfer to O. mykiss. Regardless of the source of contamination, a similar pattern of Y bioaccumulation among O. mykiss tissues was revealed: muscles < liver < gills < intestine. We conclude that the trophic transfer potential of Y is low and the evaluation of Y burden in prey cytosol appears to be a relevant predictor of Y assimilation by their consumers.
Show more [+] Less [-]Occurrence of microplastics in gastrointestinal tracts and gills of fish from Beibu Gulf, South China Sea
2020
Koongolla, J Bimali | Lin, Lang | Pan, Yun-Feng | Yang, Chang-Ping | Sun, Dian-Rong | Liu, Shan | Xu, Xiang-Rong | Maharana, Dusmant | Huang, Jian-Sheng | Li, Heng-Xiang
Microplastics are widespread across the global oceans, yet the potential risks of the ubiquitous environmental contaminant to marine organisms has been less known. Accumulation of microplastics and associated contaminants in marine fish, may pose adverse impacts to human health via seafood consumption. This study evaluated microplastic contamination in 24 fish species collected from Beibu Gulf, one of the world’s largest fishing grounds in South China Sea. Microplastics were detected in 12 fish species at an abundance of 0.027–1.000 items individual⁻¹ and found in fish stomach, intestines and gills with the count percentage of 57.7%, 34.6% and 7.7%, respectively. Transparent fibers were observed as the predominant microplastics, which might be ingested accidently by fish or transferred through other animals at lower trophic levels. Majority of microplastics were identified as polyester (44%) and nylon (38%), whereas polypropylene (6%), polyethylene (6%), and acrylics (6%) were also found. Relatively, higher microplastic abundances were found in demersal fish compared to the pelagic species. Overall, the abundance of microplastics was documented as relatively low in the commercial fish collected from the open water of Beibu Gulf, South China Sea.
Show more [+] Less [-]Waterborne and dietary accumulation of well-dispersible hematite nanoparticles by zebrafish at different life stages
2020
Huang, Bin | Cui, Yu-Qing | Guo, Wen-Bo | Yang, Liuyan | Miao, Ai-Jun
The widespread use of nanoparticles (NPs) has drawn considerable attention because of their potential toxicity and the environmental consequences thereof. However, the effects of the exposure route and life stage of an organism on the bioaccumulation and toxicity of NPs are largely unknown. In the present study, we investigated the accumulation kinetics (uptake, assimilation, and efflux) and tissue distribution of waterborne and dietary hematite NPs (HemNPs) during three life stages (embryo, larva, and adult) of the zebrafish Danio rerio. For all zebrafish life stages, the waterborne accumulation of well-dispersed HemNPs increased linearly with exposure time but decreased after reaching a maximum. The increase in HemNPs accumulation followed the order embryo > larva > adult. Compared with the waterborne route, the dietary accumulation of HemNPs in larval and adult zebrafish fluctuated, reaching a maximum after each food refreshment and then decreasing until the next food addition. Similar to waterborne exposure, adult fish accumulated less dietary HemNPs than did larvae. Nevertheless, dietary HemNPs mostly accumulated in the intestinal tract, with smaller amounts in the truncus, head, and gills, as compared with their waterborne counterparts. Moreover, in the gonad no dietary HemNPs were detected whereas accumulation via waterborne HemNPs was significant. Despite the low assimilation efficiency of dietary HemNPs, biodynamic modeling showed that the diet was the main source of particle accumulation in zebrafish. Thus, both the life stage and the exposure route should be considered in evaluations of the environmental risks of NPs.
Show more [+] Less [-]iTRAQ-based proteomic analysis on the mitochondrial responses in gill tissues of juvenile olive flounder Paralichthys olivaceus exposed to cadmium
2020
Lu, Zhen | Wang, Shuang | Ji, Chenglong | Li, Fei | Cong, Ming | Shan, Xiujuan | Wu, Huifeng
Cadmium (Cd) is an important heavy metal pollutant in the Bohai Sea. Mitochondria are recognized as the key target for Cd toxicity. However, mitochondrial responses to Cd have not been fully investigated in marine fishes. In this study, the mitochondrial responses were characterized in gills of juvenile flounder Paralichthys olivaceus treated with two environmentally relevant concentrations (5 and 50 μg/L) of Cd for 14 days by determination of mitochondrial membrane potential (MMP), observation of mitochondrial morphology and quantitative proteomic analysis. Both Cd treatments significantly decreased MMPs of mitochondria from flounder gills. Mitochondrial morphologies were altered in Cd-treated flounder samples, indicated by more and smaller mitochondria. iTRAQ-based proteomic analysis indicated that a total of 128 proteins were differentially expressed in both Cd treatments. These proteins were basically involved in various biological processes in gill mitochondria, including mitochondrial morphology and import, tricarboxylic acid (TCA) cycle, oxidative phosphorylation (OXPHOS), primary bile acid biosynthesis, stress resistance and apoptosis. These results indicated that dynamic regulations of energy homeostasis, cholesterol metabolism, stress resistance, apoptosis, and mitochondrial morphology in gill mitochondria might play significant roles in response to Cd toxicity. Overall, this study provided a global view on mitochondrial toxicity of Cd in flounder gills using iTRAQ-based proteomics.
Show more [+] Less [-]Microplastic ingestion by quagga mussels, Dreissena bugensis, and its effects on physiological processes
2020
Pedersen, Adam F. | Gopalakrishnan, Kishore | Boegehold, Anna G. | Peraino, Nicholas J. | Westrick, Judy A. | Kashian, Donna R.
The impacts of microplastic particulates in benthic freshwater organisms have been largely unexplored despite abundant plastic accumulation in the sediments of these systems. We investigated the uptake of plastic particles by benthic filter feeding quagga mussels (Dreissena bugensis) and associated toxicity exhibited through impacts on mortality, filtration rate, reproduction and oxygen consumption. Matrix Assisted Laser Desorption/Ionization Imaging Mass Spectrometry (MALDI-IMS) technology was used to assess the microplastic inclusion. For this purpose, quagga mussels were exposed to four treatments ranging from 0.0 to 0.8 g/L of a high density fluorescent red polyethylene powder in the size range of 10–45 μm for 24-h, and the targeted endpoints were quantified. Identification of several micrograms of microplastics in the digestive tract suggests rapid clearance from the water column by filtering. At the higher concentrations, about 95% of the microplastics ingested remained in the mussels after 24-h. Microplastics were found in the gills which correlated with decreasing filtration rate at higher microplastic concentrations. Despite large-scale ingestion, plastic exposure did not affect survivorship, reproduction rates, or oxygen consumption in the period examined. MALDI-IMS identified unique mass spectra that correlated with microplastic inclusion. This research suggests that microplastics can impair feeding through decreased filtration rates of filter feeding organisms, potentially resulting in a reduction of overall fitness over time and that MALDI-IMS may have the potential to identify microplastics and changes in tissue at the borders of plastic inclusion.
Show more [+] Less [-]Morphological and histopathological changes in seahorse (Hippocampus reidi) gills after exposure to the water-accommodated fraction of diesel oil
2020
Delunardo, Frederico Augusto Cariello | Paulino, Marcelo Gustavo | Medeiros, Laila Carine Campos | Fernandes, Marisa Narciso | Scherer, Rodrigo | Chippari-Gomes, Adriana Regina
Industrial activities and urbanization are the main sources of pollutants in estuarine environments. Diesel, which is widely used in urban and port activities, is an important source of hydrocarbons in the aquatic environment, and its water-accommodated fraction (WAF) is toxic to the local biota. This study was performed to analyze the effects of diesel oil WAF on fish. Specifically, we characterized the gill morphology of the seahorse Hippocampus reidi and analyzed the histopathological changes in the gills after exposure to 50% diesel oil WAF. Acute (12, 24, 48, and 96 h) and subchronic (168 and 336 h) toxicity tests were performed. Furthermore, a recovery protocol was conducted: after exposure to 50% WAF for 168 h, the fish were transferred and kept in seawater without contaminants for 336 h, for a total experimental period of 504 h. The seahorse branchial apparatus was found to be tufted with short filaments; the apical surfaces of the pavement cells in the filament and lamellar epithelia formed “crests” and had microridges. Mitochondria-rich cells were distributed exclusively in the lamellar epithelium, while mucous cells were distributed in the filament epithelium. All pathologies observed after acute and subchronic exposure featured progressive time-dependent alterations of lamellar structure that might disrupt gill physiological and metabolic functions. During the recovery period, the gill alterations were gradually repaired.
Show more [+] Less [-]Single and Combined Effects of Cadmium and Aroclor 1254 on Oxidative Stress in Gills of Mytilus coruscus
2020
Peng, Ling | Zeng, Jiangning | Liu, Qiang | Hao, Zhe | Zhang, Dongrong
Both polychlorinated biphenyls (PCBs) and cadmium (Cd) can be frequently found in marine ecosystems and have detrimental effects on marine organisms, especially on filter-feeding marine mussels. Although biological responses to single metal or PCB exposure in mussels have been well-studied, information about oxidative stress is still limited, especially in different tissues in mussels. Considering the variety of contaminants existing in the actual marine environment, the exposures of the marine mussel Mytilus coruscus to Cd²⁺ alone (0.194, 0.388, and 0.775 mg/L) and Aroclor 1254 alone (0.005, 0.010, and 0.050 mg/L) and the co-exposures of the marine mussel Mytilus coruscus to Cd²⁺ (0.194 and 0.388 mg/L) and Aroclor 1254 (0.005 and 0.010 mg/L) were tested in an 8-day exposure experiment followed by a 7-day acclimation experiment. The alterations in superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde levels in the gills of the mussels were assessed. The effects of the depressed antioxidant were induced by the exposures of Cd²⁺ and Aroclor 1254 and their co-exposures. All exposures resulted in an initial increase and then a reduction in antioxidant enzyme activities. The range and rate of the antioxidant enzyme activities were positively correlated with stress duration and the concentration of the stress material. The effect of combined stress was stronger than that of each individual stressor. The valuable information for future investigations of stress response mechanisms, especially in relation to tissue functions in marine organisms, has been provided by the results and experimental model. The study of combined pollution effects has more scientific significance for marine pollution monitoring.
Show more [+] Less [-]The Efficient Role of Rice Husk in Reducing the Toxicity of Iron and Aluminum Oxides Nanoparticles in Oreochromis niloticus: Hematological, Bioaccumulation, and Histological Endpoints
2020
Abdel-Khalek, Amr Adel | Badran, Shereen Reda | Marie, Mohamed-Assem Saeed
The present study was the first trial to use the adsorptive capacity of the rice husk to reduce the toxicological impacts of the iron and aluminum oxides nanoparticles on Oreochromis niloticus. The fish groups were subjected to a sub-lethal concentration (10 mg/l) of both metal oxides nanoparticles (in single and combined doses) with and without rice husk water treatment for 7 days. The bioaccumulation of iron and aluminum metals showed a significant increase (p < 0.05) compared with the control groups. The results revealed a tissue-specific distribution pattern as following: liver > kidney > gills > skin > muscles for iron and liver > gills > kidney > skin > muscles for aluminum. Moreover, the bioaccumulation potency of iron was greater than that of aluminum in all studied tissues. Both studied nanoparticles caused a decrease in the red blood cells count, hemoglobin content, hematocrit values, and mean corpuscular hemoglobin concentration, with an obvious increase in mean corpuscular volume and mean corpuscular hemoglobin. While all those parameters were restored more or less to that of control groups after rice husk water treatment. The histological studies of the gills, liver, and kidneys showed different histopathological alterations ranging from compensatory histological changes in the rice husk–treated groups to severe histopathological damage in the untreated groups. Based on the all studied biomarkers, the rice husk is a good absorbent for both studied nanoparticles individually or combined.
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