RESUMEN
The presence of nanoplastics (NPs) in wastewater poses a considerable risk to ecosystems. Although constructed wetlands (CWs) have the potential to removal NPs, their efficiency is limited by insufficient consideration of ecosystem integrity. Herein, three typical benthic fauna (Corbicula fluminea, Chironomus riparius and Tubifex tubifex) were added to CWs to improve the ecological integrity of CWs, and further enhance the ecological benefits. Results indicated that the addition of C. fluminea, C. riparius and T. tubifex increased NPs removal by 19.14 %, 17.02 %, and 15.76 % than that without benthic faunas, respectively. Based on fluorescence signal analysis, the presence of benthic fauna could intake NPs, and enhanced the adsorption of NPs by plants. The addition of C. fluminea significantly increased catalase (1541.82 ± 41.35 U/g), glutathione S-transferase (0.34 ± 0.02 U/g), and superoxide dismutase (116.33 ± 6.91 U/g) activities (p < 0.05) as a defense mechanism against NPs-induced oxidative stress. Metagenomic analysis revealed that the abundances of key enzymes involved in glycolysis, the tricarboxylic acid cycle, and polystyrene metabolism pathways were increased when C. fluminea was added, corresponding to the microbial degradation of NPs. Overall, the results of this study implied that the benthic fauna can efficiently remove NPs from wastewater in CWs.
Asunto(s)
Chironomidae , Contaminantes Químicos del Agua , Humedales , Animales , Contaminantes Químicos del Agua/metabolismo , Chironomidae/metabolismo , Corbicula/metabolismo , Microplásticos/toxicidad , Microplásticos/metabolismo , Aguas Residuales/química , Poliquetos/metabolismo , Biodegradación AmbientalRESUMEN
It has been demonstrated that microplastics (MPs) may be inadvertently ingested by aquatic animals, causing harm to their physiological functions and potentially entering the food chain, thereby posing risks to human food safety. To achieve an environmentally friendly and efficient reduction of MPs in freshwater environments, this experiment investigates the depuration effect of C. demersum on MPs using three common aquatic animals: Macrobrachium nipponense, Corbicula fluminea, and Bellamya aeruginosa as research subjects. The amounts of MPs, digestive enzyme activity, oxidative stress index, and energy metabolism enzyme activity in the digestive and non-digestive systems of three aquatic animals were measured on exposure days 1, 3, and 7 and on depuration days 1 and 3. The results indicated that the depuration effect of C. demersum and the species interaction were significant for the whole individual. Concerning digestive tissue, C. demersum was the most effective in purifying B. aeruginosa. When subjected to short-term exposure to MPs, C. demersum displayed a superior depuration effect. Among non-digestive tissues, C. demersum exhibited the earliest purifying effect on C. fluminea. Additionally, C. demersum alleviated physiological responses caused by MPs. In conclusion, this study underscores C. demersum as a promising new method for removing MPs from aquatic organisms.
Asunto(s)
Corbicula , Microplásticos , Contaminantes Químicos del Agua , Animales , Microplásticos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/metabolismo , Corbicula/metabolismo , Corbicula/efectos de los fármacos , Palaemonidae/metabolismo , Estrés Fisiológico , Estrés Oxidativo/efectos de los fármacos , Chlorophyceae/metabolismoRESUMEN
Cyanobacteria bloom and the secondary metabolites released by the microorganism are extremely harmful to aquatic animals, yet study on their adverse effects in zoobenthos is rare. Corbicula fluminea widely distributed in freshwater environment with algal blooms. It is a typical filter feeding zoobenthos that may be affected by the secondary metabolites of cyanobacteria due to its high filtering rate. In this study, C. fluminea was exposed to Microcystis aeruginosa exudates (MaE) for 96 h, which was obtained from 5 × 105 cells/mL and 2.5 × 106 cells/mL exponential stage M. aeruginosa culture solution that represented cyanobacteria cell density needs environmental risk precaution control and emergent control, respectively. The responses of C. fluminea critical organs to MaE were analyzed and evaluated based on histopathological sections, antitoxicity biomarkers, and organ function biomarkers. The results showed that all the organs underwent structural disorders, cell vacuolization, apoptosis, and necrosis, and the damage levels increased as MaE concentration increased. The detoxification and antioxidant defense systems biomarkers in each organ response to MaE exposure differently and the level of reaction improved when MaE concentration increased. The siphon rate and acetylcholinesterase activity showed that the filtration function decreased significantly as the MaE concentration increased. Increased activity of glutathione S-transferase and amylase in the digestive gland indicate that it is the major detoxification organ of C. fluminea. Increased vitellogenin concentration and enlarged oocytes in the gonad indicate that MaE may have an estrogenic effect on C. fluminea. This study demonstrates that cyanobacteria threat benthic bivalves by inducing oxidative stress, inhibiting filtering feeding system, and disturbing digestion system and reproduction potential of C. fluminea.
Asunto(s)
Corbicula , Microcystis , Reproducción , Animales , Microcystis/metabolismo , Corbicula/metabolismo , Corbicula/microbiología , Filtración , Biomarcadores/metabolismoRESUMEN
Per- and polyfluoroalkyl substances (PFAS) are a class of toxic manufactured chemicals in commercial and consumer products. They are resistant to environmental degradation and mobile in soil, air, and water. This study used the introduced bivalve Corbicula fluminea as a passive biomonitor at sampling locations in a primary drinking water source in Virginia, USA. Many potential PFAS sources were identified in the region. Perfluorohexane sulfonate (PFHxS) and 6:2 fluorotelomer sulfonic acid (6:2 FTS) levels were highest downstream of an airport. The highest levels of short-chain carboxylic acids were in locations downstream of a wastewater treatment plant. Measured PFAS concentrations varied by location in C. fluminea, sediment, and surface water samples. Two compounds were detected across all three mediums. Calculated partitioning coefficients confirm bioaccumulation of PFAS in C. fluminea and sorption to sediment. C. fluminea bioaccumulated two PFAS not found in the other mediums. Perfluoroalkyl carboxylic acids and short-chain compounds dominated in clam tissue, which contrasts with findings of accumulation of longer-chain and perfluorosulfonic acids in fish. These findings suggest the potential for using bivalves to complement other organisms to better understand the bioaccumulation of PFAS and their fate and transport in a freshwater ecosystem.
Asunto(s)
Corbicula , Fluorocarburos , Contaminantes Químicos del Agua , Animales , Contaminantes Químicos del Agua/análisis , Fluorocarburos/análisis , Corbicula/metabolismo , Corbicula/química , Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química , Sedimentos Geológicos/análisis , Monitoreo Biológico , VirginiaRESUMEN
This study summarizes the concentration in dry weight (dw) of several metal(oid)s (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn), as well as the abundance and characteristics of microplastics (MP) in wet weight (ww) of the soft tissues of clam Corbicula fluminea from Chubut River (Patagonia, Argentina). The contents of essential elements were in the following decreasing order: Zn > Mn > Cu > Ni; meanwhile, non-essential elements Cd, Cr and Pb were below the detection limit (<0.5 µg/g dw). A high mean concentration of As (6.1 ± 0.3 µg/g dw) was found, surpassing the maximum allowable limit established by the Argentine Food Code for bivalve molluscs. The number of MP ranged from 0.07 to 1.27 items/ind. and from 0.2 to 2.9 items/g ww. Fibers were the most common shape, mainly transparent. The size of MP ranged from 42 to 1917 µm, accounting for 62 % of MP between 50 and 450 µm. The dominant polymer was PET based on the results of Raman spectroscopy. Based on the widespread distribution of MP in the environment and the wide range of effects on organisms, it is necessary to develop long-term monitoring programs for MP contamination in different environmental matrices. Understanding the bioaccumulation of MP in bivalves is crucial to assess the potential risk to human health through consumption and to the ecosystem. We propose that the widespread Asian clam could serve as a useful biomonitor for MP and As pollution in freshwater and estuarine environments such as the Chubut River.
Asunto(s)
Corbicula , Monitoreo del Ambiente , Metales , Microplásticos , Ríos , Contaminantes Químicos del Agua , Animales , Contaminantes Químicos del Agua/análisis , Corbicula/efectos de los fármacos , Corbicula/metabolismo , Ríos/química , Argentina , Microplásticos/análisis , Metales/análisis , Metales/metabolismoRESUMEN
The increasing attention that carbon-based nanomaterials have attracted due to their distinctive properties makes them one of the most widely used nanomaterials for industrial purposes. However, their toxicity and environmental effects must be carefully studied, particularly regarding aquatic biota. The implications of these carbon-based nanomaterials on aquatic ecosystems, due to their potential entry or accidental release during manufacturing and treatment processes, need to be studied because their impacts upon living organisms are not fully understood. In this research work, the toxicity of oxidized multi-walled carbon nanotubes (Ox-MWCNTs) was measured using the freshwater bivalve (Corbicula fluminea) after exposure to different concentrations (0, 0.1, 0.2, and 0.5 mg·L-1 Ox-MWCNTs) for 14 days. The oxidized multi-walled carbon nanotubes were analyzed (pH, Raman microscopy, high-resolution electron microscopy, and dynamic light scattering), showing their properties and behavior (size, aggregation state, and structure) in water media. The antioxidant defenses in the organism's digestive gland and gills were evaluated through measuring oxidative stress enzymes (glutathione-S-transferase, catalase, and superoxide dismutase), lipid peroxidation, and total ubiquitin. The results showed a concentration-dependent response of antioxidant enzymes (CAT and GST) in both tissues (gills and digestive glands) for all exposure periods in bivalves exposed to the different concentrations of oxidized multi-walled carbon nanotubes. Lipid peroxidation (MDA content) showed a variable response with the increase in oxidized multi-walled carbon nanotubes in the gills after 7 and 14 exposure days. Overall, after 14 days, there was an increase in total Ub compared to controls. Overall, the oxidative stress observed after the exposure of Corbicula fluminea to oxidized multi-walled carbon nanotubes indicates that the discharge of these nanomaterials into aquatic ecosystems can affect the biota as well as potentially accumulate in the trophic chain, and may even put human health at risk if they ingest contaminated animals.
Asunto(s)
Corbicula , Nanotubos de Carbono , Contaminantes Químicos del Agua , Animales , Humanos , Corbicula/metabolismo , Antioxidantes/metabolismo , Nanotubos de Carbono/toxicidad , Ecosistema , Estrés Oxidativo , Glutatión Transferasa/metabolismo , Agua Dulce , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/análisisRESUMEN
The brackish water clam (Corbicula japonica) is constantly exposed to stressful salinity gradients and high levels of heavy metals in the freshwater-saltwater interface of estuary environments, which are introduced from upstream regions and land. To identify the key molecular pathways involved in the response to salinity changes and heavy metal bioaccumulation, we obtained the transcriptomes of C. japonica inhabiting different salinities and heavy metal distributions in Gwangyang Bay (Korea) using RNA sequencing. Among a total of 404,486 assembled unigenes, 5534 differentially expressed genes were identified in C. japonica inhabiting different conditions, 1549 of which were significantly upregulated and 1355 were significantly downregulated. Correlation analyses revealed distinct gene expression patterns between the low and high conditions of salinity and heavy metal bioaccumulation. Functional annotation revealed significant downregulation of genes involved in "ubiquitin-dependent protein catabolic process," "tricarboxylic acid cycle," and "intracellular protein transport" in C. japonica from the high condition compared to the low condition. Transcription and translation pathways were significantly enriched in the high condition. Additionally, upon comparison of the low and high conditions by qRT-PCR and proteasome enzyme activity analyses, our findings demonstrated that environmental stress could suppress the ubiquitin-proteasome complex (UPC). Additionally, transcriptomic changes under high salinity stress conditions may be related to an increase in cellular protection by defense enzymes, which leads to more energy being required and a disruption of energy homeostasis. Ultimately, this could cause growth retardation in the clam C. japonica. In summary, this study provides the first evidence of UPC suppression induced by a combination of high salinity and heavy metal bioaccumulation stress in C. japonica, which could compromise the survival and growth of estuarine bivalves.
Asunto(s)
Corbicula , Metales Pesados , Animales , Corbicula/metabolismo , Bioacumulación , Salinidad , Complejo de la Endopetidasa Proteasomal/metabolismo , Aguas Salinas , Metales Pesados/análisis , Trastornos del Crecimiento , Ubiquitinas/metabolismoRESUMEN
Microplastics (MP) and microcystins (MCs) are two co-occurring pollutants in freshwater ecosystems that pose significant risks to aquatic organisms and human health. This study investigates the interactions between MP and MCs and their effects on the metabolic responses of freshwater aquaculture. Asian clams have been used as an indicator of microplastic pollution in freshwater ecosystems. The present study investigates metabolic responses of Asian clams during microplastic and microcystin-LR stress to identify health impacts and elucidate mechanistic effects of external stressors on Asian clams. A liquid chromatography/mass spectrometry (LC-MS)-based metabolomics approach was used to identify metabolic perturbations and histological section technique was used to assess changes of tissues from different Asian clam treatment groups. The results showed significantly pathological changes in the gills and hepatopancreas in experimental clam compared to control (healthy) clam. Metabolomics revealed alterations of many metabolites in the hepatopancreas of six Asian clam comparison groups, reflecting perturbations in several molecular pathways, including energy metabolism, amino acid metabolism, protein degradation/tissue damage, and oxidative stress. Overall, this study emphasizes the importance of understanding the interactions between MP and MCs and the need for proactive measures to safeguard freshwater ecosystems and human health.
Asunto(s)
Corbicula , Contaminantes Químicos del Agua , Animales , Humanos , Corbicula/metabolismo , Plásticos/metabolismo , Microplásticos/metabolismo , Microcistinas/análisis , Microcistinas/metabolismo , Ecosistema , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/metabolismoRESUMEN
Benzotriazole ultraviolet stabilizers (BUVSs) are widespread emerging pollutants, which can pose exposure risks to benthic organisms. However, the toxicity and mechanisms of BUVSs congeners in benthic clams are far from elucidated. In this study, Asian clams (Corbicula fluminea) were exposed to one of UV-234, UV-326, UV-329, or UV-P at environmentally relevant levels (0.1, 1, and 10 µg/L) for 21 days. Filtration rate (FR) was increased in clams exposed to all BUVSs and there were notable histopathologic changes, including irregular digestive lumen, lipid droplet vacuolation, and degraded epithelial cells. To determine the molecular underpinnings following BUVSs exposure, the transcriptome responses in digestive glands were compared. Differentially expressed genes shared among BUVSs treatments were associated with focal adhesion, TNF-α/NF-κB proinflammatory pathways, and apoptosis. Following this, biochemical analysis of biomarkers related to apoptosis were conducted to further validate response. Exposure to BUVSs inhibited anti-oxidant enzyme activity and induced oxidative stress. Heat shock proteins were also triggered with exposure, and there was an induction of caspase-3 and caspase-9 activity. Molecular responses were not identical in the digestive gland of C. fluminea when comparing responses to BUVSs; nevertheless conserved mechanism (impairment of the oxidative defense system, immune system disruption, and induction of apoptosis) among BUVSs congeners was noted. This study provides novel insight into the toxicity and hazards of BUVSs in benthic organisms.
Asunto(s)
Corbicula , Contaminantes Químicos del Agua , Animales , Antioxidantes/metabolismo , Corbicula/metabolismo , Estrés Oxidativo , Toxicogenética , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/metabolismoRESUMEN
The frequent occurrence of cyanobacterial blooms (CYBs) caused by toxic Microcystis aeruginosa poses a great threat to aquatic organisms. Although freshwater benthic bivalves have proven to be capable of uptake high levels of microcystins (MCs) due to their filter-feeding habits, there is a paucity of information concerning their systemic resistance mechanisms to MCs. In this study, the resistance mechanisms in Corbicula ï¬uminea (O. F. Müller, 1774) in response to the exposure of toxic M. aeruginosa were explored through transcriptional analysis combined with histopathological and biochemical phenotypic analysis. Toxic M. aeruginosa exposure caused dose-dependent histological damage in the hepatopancreas. The conjugation reaction catalyzed by glutathione S-transferases was vulnerable to being activated by high concentrations of M. aeruginosa (10 ×105 cells mL-1). Additionally, reactive oxygen species scavenging processes mediated by superoxide dismutase and catalase were active in the initial stage of toxic M. aeruginosa exposure. The results of the integrated biomarker response index suggested that the biotransformation and antioxidant defense system in C. ï¬uminea could be continuously activated after acute exposure to the high concentration of toxic M. aeruginosa. The eggNOG and GO analysis of the differentially expressed genes (DEGs) indicated that DEGs were significantly enriched in transporter activity, oxidant detoxification and response to oxidative stress categories, which were consistent with the alterations of biochemical indices. Besides, DEGs were significantly annotated in a few KEGG pathways involved in biotransformation (oxidation, cooxidation and conjugation) and immunoreaction (lysosome and phagosome responses), which could be responsible for the tolerance of C. ï¬uminea to toxic M. aeruginosa. These findings improve our understanding of potential resistance mechanisms of freshwater bivalves to MCs.
Asunto(s)
Corbicula , Microcystis , Animales , Corbicula/genética , Corbicula/metabolismo , Microcystis/genética , Microcystis/metabolismo , Transcriptoma , Antioxidantes/metabolismo , Estrés Oxidativo/genética , Microcistinas/toxicidad , Microcistinas/metabolismoRESUMEN
Wildfires constitute a source of contamination to both freshwater and marine ecosystems. This study aimed to compare the antioxidant defense response of the freshwater clam Corbicula fluminea and the marine cockle (Cerastoderma edule) to wildfire ash exposure and the concomitant metal body burden. Organisms were exposed to different concentrations (0%, 12.5%, 25%, 50%, and 100%) of aqueous extracts of Eucalypt ash (AEAs) from a moderate-to-high severity wildfire. The activity of various enzymes, as well as lipid peroxidation, protein content, and metal body burden, were determined after 96 h of exposure. A significant increase in the protein content of soft tissues was observed for C. edule at AEA concentrations ≥ 25%, unlike for C. fluminea. Similarly, significant effects on lipid peroxidation were observed for cockles, but not for clams. For both species, a significant effect in the total glutathione peroxidase activity was observed at AEA concentrations ≥ 25%. Relative to the control, AEAs-exposed clams showed higher Cd content, whereas AEAs-exposed cockles showed higher Cu content, thus exhibiting different responses to the exposure to wildfire ash. The susceptibility of bivalves to ashes, at environmentally relevant concentrations, raises concern about the effects of post-fire runoff to bivalve species.
Asunto(s)
Corbicula , Contaminantes Químicos del Agua , Incendios Forestales , Animales , Antioxidantes/metabolismo , Ecosistema , Carga Corporal (Radioterapia) , Metales/toxicidad , Metales/metabolismo , Corbicula/metabolismo , Proteínas , Agua Dulce , Contaminantes Químicos del Agua/análisisRESUMEN
The NF-κB signaling pathway is the most critical pathway in innate immunity. IκB (Cactus) is the primary cytoplasmic inhibitor of NF-κB (Dorsal). In this study, we found that ammonia exposure could significantly induce the expression of Cactus, in a dose-dependent manner in different tissues, with the highest expression in the gill of Corbicula fluminea. The expression pattern-related elements (Tube and Dorsal) in the NF-κB signaling pathway were also analyzed, showing significant up-regulation in 48 h. There was an inhibitory effect between up-regulated Cactus and Dorsal in 72 h, which may regulate Dorsal as a negative feedback pathway function to control the expression of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α). Besides, through molecular docking simulation, we found that the Cactus could be directly activated by NH3, complementing the regulatory mechanism of the Cactus. To further test our hypothesis, the levels of pro-inflammatory cytokines decreased after adding PDTC (the antioxidant of Cactus/IκB), suggesting that PDTC can prevent the degradation of Cactus, inhibit Dorsal translocating into the nucleus, and activate the pro-inflammatory cytokines. This revealed the inhibitory effect of Cactus on activating Dorsal/NF-κB factors in the NF-κB signaling pathway. Thus, we suggested that the Cactus is an essential regulator of ammonia-activated inflammation in C. fluminea, which was reported to be activated only by bacteria and immune stimulators. Our study provides a new perspective on the mechanism of ammonia toxicity in invertebrates.
Asunto(s)
Amoníaco , Corbicula , Proteínas I-kappa B , FN-kappa B , Amoníaco/toxicidad , Citocinas/metabolismo , Proteínas I-kappa B/metabolismo , Simulación del Acoplamiento Molecular , FN-kappa B/metabolismo , Corbicula/efectos de los fármacos , Corbicula/metabolismoRESUMEN
As filter-feeders, bivalves naturally come into direct contact with microcystins (MCs) in eutrophic water bodies suffering from cyanobacteria blooms. To date, however, no studies have quantified the dynamics of microcystin accumulation and depuration in the edible freshwater bivalve Corbicula fluminea when exposed to dense bloom concentrations of Microcystis aeruginosa, while considering dynamic changes of biochemical indexes and feeding structure. In the present study, the bioaccumulation and detoxification of microcystin-LR (MC-LR) in C. fluminea were investigated. Our results showed that C. fluminea would graze equally efficiently on green algae and M. aeruginosa, irrespective of whether the M. aeruginosa strains were toxic or non-toxic. MCs could be accumulated and depurated by C. fluminea efficiently. In addition, linear and exposure time-dependent MC-LR accumulation patterns were observed in C. fluminea. Activities of biotransformation (glutathione S-transferase, GST) and antioxidant enzymes (superoxide dismutase, SOD, and catalase, CAT) and malondialdehyde (MDA) contents in various tissues of treated clams were stimulated by MCs in a tissue-specific manner. Our findings indicated that C. fluminea hepatopancreas was the primary target organ for MC-LR detoxification processes, as evidenced by a significant increase in GST activity. Besides, gills and mantle were more sensitive than the other tissues to oxidative stress in the initial microcystin exposure period with a significant increase in SOD activity. The scanning electron microscopy (SEM) observations revealed that the lateral cilia in the gill aperture were well developed during the MCs exposure period, which could perform the filter-feeding function instead of the damaged frontal cilium. This study provides insight into the possible tolerance of C. fluminea exposed to dense bloom concentrations of M. aeruginosa.
Asunto(s)
Corbicula , Microcistinas , Microcystis , Animales , Corbicula/metabolismo , Corbicula/microbiología , Conducta Alimentaria , Microcistinas/metabolismo , Microcystis/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
Air exposure is a common stress for Corbicula fluminea, an economically important freshwater shellfish consumed in China, during aquaculture and transportation. However, little is known about its molecular responses to air exposure. Therefore, this study used a combination of PacBio full-length and Illumina transcriptomes to investigate its molecular responses to air exposure. A total of 36,772 transcripts were obtained using PacBio sequencing. Structural analysis identified 32,069 coding sequences, 1906 transcription factors, 8873 simple sequence repeats, and 17,815 long non-coding RNAs. Subcellular localization analysis showed that most transcripts were located in the cytoplasm and nucleus. After 96-h of air exposure, 210 differentially expressed genes (DEGs) in the gill were obtained via Illumina sequencing. Among these DEGs, most of the genes related to glycolysis, tricarboxylic acid cycle, lipid metabolism, and amino acid metabolism were upregulated. Additionally, many DEGs associated with immunity, cytoskeleton reorganization, autophagy, and ferroptosis were identified. These findings indicated that metabolic strategy change, immune response, cytoskeleton reconstruction, autophagy, and ferroptosis might be the important mechanisms that C. fluminea use to cope with air exposure. This study will enrich the gene resources of C. fluminea and provide valuable data for studying the molecular mechanisms coping with air exposure in C. fluminea and other freshwater mollusks.
Asunto(s)
Corbicula , Contaminantes Químicos del Agua , Aminoácidos/metabolismo , Animales , Corbicula/genética , Corbicula/metabolismo , Branquias , Secuenciación de Nucleótidos de Alto Rendimiento , Factores de Transcripción/metabolismo , Transcriptoma , Contaminantes Químicos del Agua/metabolismoRESUMEN
Changes in natural estuarine environment and anthropogenic disturbances are becoming significant threats to organisms, particularly bivalves. A deeper understanding of the relationship between biochemical- and individual-level responses is necessary to assess the combined effects of natural and anthropogenic factors on bivalves. To the best of our knowledge, this is the first study where the oxygen radical absorbance capacity (ORAC) and carbon-based scope for growth (C-SFG) were applied as biomarkers to evaluate the response of the brackish water clam Corbicula japonica to four spatiotemporally varying environmental factors. High water temperature and food availability supported C-SFG while high salinity inhibited it. Most of wastewater (WW) treatments resulted in negative C-SFG values because of a reduced clearance rate and increased excretion rate. In particular, high food availability with WW treatment resulted in the lowest C-SFG value of -114⯵gâ¯C·ind-1â¯h-1. The ORAC was activated in response to high salinity with WW treatment (pâ¯<â¯0.05). To ascertain the combined effects of the natural and anthropogenic factors, principal component and cluster analyses were performed on the ORAC and C-SFG data. Anthropogenic WW was found to have different effects on the physiological and biochemical biomarkers according to the natural conditions. A roughly negative correlation was observed between ORAC and C-SFG because activation of the antioxidant capacity can influence the growth potential of the clams through the additional use of available metabolic energy. However, some exceptions were observed where both the ORAC and C-SFG values were either high or low, which could be because the C-SFG response varies depending on different metabolic behaviors even when the ORAC response remains the same. These results indicate that the biochemical-level response (i.e., ORAC) of C. japonica can be interpreted using individual-level response (i.e., C-SFG), but careful attention must be given to over- or underestimation.
Asunto(s)
Corbicula , Animales , Efectos Antropogénicos , Antioxidantes/metabolismo , Carbono/metabolismo , Corbicula/metabolismo , Aguas SalinasRESUMEN
This study investigated seasonal trends in bioaccumulation potential and toxic effects of mercury (Hg) in Asian clams (Corbicula fluminea) and microbial community. For this, a clam-exposure experiment was performed during summer, fall, and winter seasons in four different sites (HS1: control/clean site; HS2, HS3, and HS4: contaminated sites) of Hyeongsan River estuary, South Korea. Total mercury (THg) and methylmercury (MeHg) in whole sediments were highest at HS4 site during fall, sustained similar levels during winter, but decreased during summer. Unlike whole sediment, pore water reported higher levels in summer, and gradually declined during fall and winter. Asian clams from HS4 site collected during summer presented highest bioaccumulations of THg (521.52 µg/kg, dry weight) and MeHg (161.04 µg/kg, dry weight), which also correlated with the higher levels of Hg present in pore water in the same season. Moreover, biota-sediment-pore water accumulation factor (BSpAF) were comparatively greater in clams collected from HS2â¼HS4 compared to HS1 sites, suggesting that porewater was a better indicator of accumulation of Hg. Upregulation of biomarker genes responsible for detoxifying process (gsts1), scavenging oxidative stress (cat), and protein reparation (hsp70 and hsp90) were observed in clams collected from HS2â¼HS4. The overexpression of these biomarkers implied that Asian clams can be considered as promising warning tools for Hg-contamination. Both bacterial and metabolic diversities were negatively affected by higher levels of THg and MeHg. Phylum Proteobacteria was enriched in HS2â¼HS4 compared to HS1. In contrast, phylum Bacteroidetes showed a reverse trend. The metabolic profile was highest in HS1 and lowest in HS4, revealing higher stress of Hg in HS4 site. Overall, the outcomes of this field study broaden the information on seasonal trends of bioaccumulation of Hg and its toxic effects. These findings may be helpful in Hg monitoring and management programs in other river systems.
Asunto(s)
Corbicula , Mercurio , Compuestos de Metilmercurio , Microbiota , Contaminantes Químicos del Agua , Animales , Bioacumulación , Corbicula/metabolismo , Monitoreo del Ambiente , Sedimentos Geológicos , Mercurio/análisis , Compuestos de Metilmercurio/toxicidad , Estaciones del Año , Agua , Contaminantes Químicos del Agua/análisisRESUMEN
Graphene oxide (GO), a frequently utilized graphene family nanomaterial, is inevitably released into the aquatic environment and interacts with organic pollutants, including perfluorooctane sulfonate (PFOS), a well-known persistent organic pollutant. To determine the adverse effects of GO chronic exposure on PFOS bioaccumulation and toxicity, adult freshwater bivalves, namely Asian clams (Corbicula fluminea) were treated for 28 days with PFOS (500 ng/L) and different concentrations of GO (0.2, 1, 5 mg/L) as PFOS single and GO single exposure groups, as well as PFOS-GO mixture exposure groups. Our results demonstrated that the bioaccumulation of PFOS was significantly enhanced by co-exposure in gills and visceral masses, which was 1.64-2.91 times higher in gills than in visceral masses. Both single, as well as co-exposure, caused a significant reduction in clams' siphoning behavior, compared to the controls. Further, the co-exposure significantly increased the production of reactive oxygen species (ROS), exacerbating malondialdehyde (MDA) content, enhancing superoxide dismutase (SOD) and catalase (CAT), while decreasing glutathione reductase (GR) and glutathione S-transferase (GST) enzymatic activities in clam tissues. And co-exposure significantly altered the expressions of se-gpx, sod, cyp30, hsp40, and hsp22 genes (associated with oxidative stress and xenobiotic metabolism) both in gills and visceral masses. Moreover, co-exposure caused significant histopathological changes such as cilia degradation in the gills, expansion of tubule lumens in digestive glands, and oocyte shrinkage in gonads. Finally, the enhanced integrated biomarker response (EIBR) index revealed that co-exposure to 500 ng/L PFOS + 1 mg/L/5 mg/L GO was the most stressful circumstance. Overall, our findings suggested that the presence of GO increased PFOS bioaccumulation in tissues, inducing multifaceted negative implications at molecular and behavioral levels through oxidative stress generation in Asian clams.
Asunto(s)
Corbicula , Grafito , Contaminantes Químicos del Agua , Ácidos Alcanesulfónicos , Animales , Corbicula/metabolismo , Fluorocarburos , Agua Dulce , Estrés Oxidativo , Superóxido Dismutasa/metabolismo , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidadRESUMEN
Chromium has two main oxidation states, Cr(III) and Cr(VI), that can occur simultaneously in natural waters. Current consensus holds that Cr(VI) is of high ecotoxicological concern, but regards Cr(III) as poorly bioavailable and relatively non-toxic. In this work, the effects and bioaccumulation of Cr(III), Cr(VI) and their mixture were studied using the freshwater clam Corbicula fluminea as a model organism. Mixture exposures were carried out using solutions isotopically enriched in 50Cr(III) or 53Cr(VI), allowing to quantify the contribution of each redox form to total Cr accumulation in the clams. Following exposure to individual redox forms, Cr(III) accumulated preferentially in the digestive glands and Cr(VI) in the gills of C. fluminea. In mixture exposures, both redox forms accumulated mainly in the gills; the concentration of Cr(III) in the digestive glands being much lowered compared with individual exposures. Both oxidation states affected the expression of biomarkers related to energy reserves, cellular damage and mitochondrial functioning, as well as the expression of mRNA for detoxification genes. The observed effects differed between gills and digestive glands. The present study suggests that Cr(III) is a bioavailable and biologically active elemental species deserving more consideration by the ecotoxicological community.
Asunto(s)
Corbicula , Contaminantes Químicos del Agua , Animales , Bioacumulación , Cromo/análisis , Corbicula/metabolismo , Agua Dulce , Contaminantes Químicos del Agua/análisisRESUMEN
Polyunsaturated phospholipids are abundant in clam (Corbicula fluminea) but difficult to be fully extracted. Herein, graphene/fibrous silica (G/KCC-1) nanohybrids were synthesized, characterized, and applied for solid-phase extraction (SPE) of phospholipids in clam. The effectiveness of G/KCC-1 SPE was verified by hydrophilic interaction chromatography mass spectrometry (HILIC-MS) based lipidomics and statistical analysis. The ions of PE 16:0/18:1 (m/z 716.4), PC 16:0/20:5 (m/z 824.6) and etc. were regarded as the main difference among the crude lipids, acetone washed extract, and eluate of G/KCC-1 SPE. Finally, this method was validated in terms of linearity (R2 0.9965 to 0.9981), sensitivity (LOD 0.19-0.51 µg·mL-1 and LOQ 0.48 - 1.47 µg·mL-1), and precision (RSDintra-day ≤ 7.16% and RSDinter-day ≤ 7.30%). In conclusion, the G/KCC-1 SPE and HILIC-MS method was shown to be accurate and efficient in selective extracting and phenotyping phospholipids in C. fluminea.
Asunto(s)
Cromatografía Liquida , Corbicula/metabolismo , Grafito/química , Lipidómica/métodos , Espectrometría de Masas , Dióxido de Silicio/química , Extracción en Fase Sólida , Animales , Interacciones Hidrofóbicas e Hidrofílicas , Fenotipo , Alimentos Marinos/análisisRESUMEN
Among UV-filters, benzophenones are one of the most abundantly used and detected groups in the environment. Bisphenols are also one of the most widely used chemicals in plastics, but their demonstrated deleterious effects on several organisms and humans have led to the production of alternative analogues. However, few comparative studies on the ecotoxicological effects of these derivatives or analogues have been carried out. The present study aimed to investigate the effects of two benzophenones (BP-3 and BP-4) and two bisphenols (BPA and BPS) in a short-term exposure of the freshwater endobenthic bivalve Corbicula fluminea. Clams were exposed for 96 h to several concentrations of the four pollutants: BP-3 (0.63; 1.25; 2.5; 5 mg l-1), BP-4 (4.75; 9.5; 19; 38 mg l-1), BPA (3.75; 7.5; 15; 30 mg l-1), and BPS (2.5; 5; 10; 20 mg l-1). The comparative acute toxicity of these pollutants was evaluated by the analysis of the post-exposure filtering capacity of clams, lipid peroxidation (LP) levels and the activity of the antioxidant enzymes catalase (CAT) and glutathione reductase (GR). After the exposure period, except for BP-4, the chemicals tested seemed to be detected by clams and provoked valve closure, decreasing filter-feeding in a concentration-dependent manner. Furthermore, C. fluminea exposed to the highest concentrations of BP-3, BP-4 and BPA showed a significant increase in LP, CAT and GR activities with respect to their controls. BP-3 and BPA were the most toxic compounds showing significant differences in all the parameters analysed at the highest concentrations assayed. However, clams exposed to BPS showed only significant alterations in filtration parameters and in GR activity, in the two highest concentrations tested, indicating that this compound was the least toxic to clams. Obtained results highlight the importance of investigating the effects that emerging pollutants have on aquatic organisms.