Battery Of Bioassays Research Articles

Ecotoxicological Effects of Transformed Silver and Titanium Dioxide Nanoparticles in the Effluent from a Lab-Scale Wastewater Treatment System.

In this study, a lab-scale wastewater treatment plant (WWTP), simulating biological treatment, received 10 μg/L Ag and 100 μg/L TiO2 nanoparticles (NPs) for 5 weeks. NP partitioning was evaluated by size fractionation (>0.7 μm, 0.1-0.7 μm, 3 kDa-0.1 μm, < 3 kDa) using inductively coupled plasma mass spectrometry (ICP-MS), single particle ICP-MS and transmission electron microscopy. The ecotoxicological effects of the transformed NPs in the effluent were assessed using a battery of marine and freshwater bioassays (algae and crustaceans) and an in vitro gill cell line model (RTgill-W1). TiO2 aggregates were detected in the effluent, whereas Ag NPs (0.1-0.22 μg/L) were associated with S, Cu, Zn. Fractionation showed that >80% of Ag and Ti were associated with the effluent solids. Increased toxicity was observed during weeks 2-3 and the effects were species-dependent; with marine epibenthic copepods and algae being the most sensitive. Increased reactive oxygen species formation was observed in vitro followed by an increase in epithelial permeability. The effluent affected the gill epithelium integrity in vitro and impacted defense pathways (upregulation of multixenobiotic resistance genes). To our knowledge, this is the first study to combine a lab-scale activated sludge WWTP with extensive characterization techniques and ecotoxicological assays to study the effects of transformed NPs in the effluent.

Combining in vitro reporter gene bioassays with chemical analysis to assess changes in the water quality along the Ammer River, Southwestern Germany

BackgroundRivers receive water and associated organic micropollutants from their entire catchment, including from urban, agricultural and natural sources, and constitute an important environmental component for catalyzing pollutant turnover. Environmental removal processes were extensively investigated under laboratory conditions in the past but there is still a lack of information on how organic micropollutants attenuate on the catchment scale. The aim of this study was to describe the chemical and toxicological profile of a 4th order river and to characterize in-stream processes. We propose indicator chemicals and indicator in vitro bioassays as screening methods to evaluate micropollutant input and transport and transformation processes of the chemical burden in a river. Carbamazepine and sulfamethoxazole were selected as indicators for dilution processes and the moderately degradable chemicals tramadol and sotalol as indicators for potential in-stream attenuation processes. The battery of bioassays covers seven environmentally relevant modes of action, namely estrogenicity, glucocorticogenic activity, androgenicity progestagenic activity and oxidative stress response, as well as activation of the peroxisome proliferator-activated receptor and the aryl hydrocarbon receptor, using the GeneBLAzer test battery and the AhR-CALUX and AREc32 assays.ResultsBoth approaches, targeted chemical analysis and in vitro bioassays, identified a wastewater treatment plant (WWTP) as a major input source of organic micropollutants that dominantly influenced the water quality of the river. Downstream of the WWTP the amount of detected chemicals and biological effects decreased along the river flow. The organic indicator chemicals of known degradability uncovered dilution and potential loss processes in certain river stretches. The average cytotoxic potency of the river water decreased in a similar fashion as compounds of medium degradability such as the pharmaceutical sotalol.ConclusionsThis study showed that the indicator chemical/indicator bioassay approach is suitable for identifying input sources of a mixture of organic micropollutants and to trace changes in the water quality along small rivers. This method forms the necessary basis for evaluating the natural attenuation processes of organic micropollutants on a catchment scale, especially when combined with enhanced sampling strategies in future studies.

Iron and Iron Oxide Nanoparticles Synthesized Using Green Tea Extract: Improved Ecotoxicological Profile and Ability to Degrade Malachite Green.

In recent years, iron-based nanoparticles (FeNPs) have been successfully used in environmental remediation and water treatment. This study examined ecotoxicity of two FeNPs produced by green tea extract (smGT, GTFe) and their ability to degrade malachite green (MG). Their physicochemical properties were assessed using transmission electron microscopy, X-ray powder diffraction, dynamic light scattering, and transmission Mössbauer spectroscopy. Using a battery of ecotoxicological bioassays, we determined toxicity for nine different organisms, including bacteria, cyanobacterium, algae, plants, and crustaceans. GTFe, amorphous complex of Fe(II, III) ions and polyphenols from green tea extract, proved low capacity to degrade MG and was toxic to all tested organisms. Superparamagnetic iron oxide NPs (smGT) derived from GTFe, showed no toxic effect on most of the tested organisms up to a concentration of 1g/L, except for algae and cyanobacterium and removed 93 % MG at concentration 125 mg Fe/L after 60 minutes. The procedure described in this paper generates new superparamagnetic iron oxide NPs from existing and toxic GTFe, which are nontoxic and has degradative potential for organic compounds. These findings suggest low ecotoxicological risks and suitability of this green-synthesized FeNPs for environmental remediation purposes.

In vitro bioanalysis of drinking water from source to tap

The presence of chemical pollutants in sources of drinking water is a key environmental problem threatening public health. Efficient removal of pollutants in drinking water treatment plants (DWTPs) is needed as well as methods for assessment of the total impact of all present chemicals on water quality. In the present study we have analyzed the bioactivity of water samples from source to tap, including effects of various water treatments in a DWTP, using a battery of cell-based bioassays, covering health-relevant endpoints. Reporter gene assays were used to analyze receptor activity of the aryl hydrocarbon receptor (AhR), estrogen receptor (ER), androgen receptor (AR), peroxisome proliferator-activated receptor alpha (PPARα) and induction of oxidative stress by the nuclear factor erythroid 2-related factor 2 (Nrf2). DNA damage was determined by Comet assay. Grab water samples were concentrated by HLB or ENV solid phase extraction and the water samples assayed at a relative enrichment factor of 50. The enrichment procedure did not induce any bioactivity. No bioactivity was detected in Milli-Q water or drinking water control samples. Induction of AhR, ER and Nrf2 activities was revealed in source to tap water samples. No cytotoxicity, PPARα or AR antagonist activity, or DNA damage were observed in any of the water samples. A low AR agonist activity was detected in a few samples of surface water, but not in the samples from the DWTP. The treatment steps at the DWTP, coagulation, granulated activated carbon filtration, UV disinfection and NH2Cl dosing had little or no effect on the AhR, Nrf2 and ER bioactivity. However, nanofiltration and passage through the distribution network drastically decreased AhR activity, while the effect on Nrf2 activity was more modest and no apparent effect was observed on ER activity. The present results suggest that bioassays are useful tools for evaluation of the efficiency of different treatment steps in DWTPs in reducing toxic activities. Bioassays of AhR and Nrf2 are useful for screening of effects of a broad range of chemicals in drinking water and ER activity can be monitored with a high sensitivity.

Toxicity assessment of sediments from the Liaohe River Protected Area (China) under the influence of ammonia nitrogen, heavy metals and organic contaminants

The aim of this study was to evaluate the toxicity of ammonia nitrogen, metals and organic contaminants in sediment collected from the Liaohe River Protected Areas. The TIE was applied to 16 samples. The zeolite, resin, and coconut charcoal were used to mask toxicity of the three kinds of pollutants, respectively. Then quantitative analyses together with a battery of bioassays were performed to evaluate toxic effects. At last, the spiking tests were used to confirm the major contributors to toxicity. The results of toxicity identification showed the ammonia nitrogen, γ-HCHs, As and Cd may cause toxic hazards to benthic organisms. The significant correlation between the survival and volume ratio of the sediment and overlying water confirmed ammonia nitrogen and Cd were the major toxic pollutants that cause the biological toxicity. We confirmed bioassays combined with masking agent, spiking tests and quantitative analyses were suitable tools for detecting toxicity.

Use of Chemical Indicators and Bioassays in Bottom Sediment Ecological Risk Assessment

This study is was designed to assess the ecological risk associated with chemical pollution caused by heavy metals and PAHs on the basis of their ecotoxicological properties in sediments collected from the Rzeszów dam reservoir (Poland). The sediment samples were collected from three sampling stations: S1—inlet, backwater station, S2—middle of reservoir, S3 outlet, near the dam. The sediments’ toxicity was evaluated using a battery of bioassays (Phytotoxkit, Phytotestkit, Ostracodtoxkit F, and Microtox). The highest content of metals (120.5 mg Zn; 22.65 mg Pb; 8.20 mg Cd ∙ kg−1 dw) and all PAHs (∑9361 μg ∙ kg−1 dw) in sediments was found at station S1. The lowest content of metals (86.72 mg Zn; 18.07 mg Cu; 17.20 mg Pb; 3.62 mg Cu; 28.78 mg Ni; 30.52 mg Cr ∙ kg−1 dw) and PAHs (∑4390 μg ∙ kg−1 dw) was found in the sediment from station S2. The ecological risk assessment of the six metals and eight PAHs revealed a high potential toxicity in sediments from stations S1 (PECq = 0.69) and S3 (PECq = 0.56) and a low potential toxicity in sediments from station S2 (PECq = 0.38). The studies also showed the actual toxicity of sediments for the test organisms. The sediment pore water was least toxic compared to the whole sediment: solid phases > whole sediment > pore water. The most sensitive organism for metals and PAHs in bottom sediments was Lepidium sativum, and in pore water—Sorghum saccharatum. The concentration of metals and PAHs in bottom sediments generally did not affect the toxicity for other organisms. Clay content and organic C content are likely to be important factors, which control heavy metal and PAH concentrations in the sediments. Data analysis by PCA found the same origin of metals as well as PAHs—mainly anthropogenic sources. The obtained information demonstrated the need to integrate ecotoxicological and chemical methods for an appropriate ecological risk assessment.

Assessing changes in the toxicity of effluents from intensive marine fish farms over time by using a battery of bioassays.

Although intensive marine fish farming is often assumed to be eco-friendly, the associated activity can lead to chronic exposure of marine organisms to potentially toxic discharges. Moreover, despite the increasing popularity of integrated multi-trophic aquaculture (IMTA), studies of the effects of fish farm effluents are almost non-existent. In the present study, the changes in the toxic potential of effluents from five land-based marine fish farms in NW Spain subjected for different lengths of time to a biodegradation procedure (for 0, 48, 120, and 240h) were assessed in a battery of bioassays including organisms from different trophic levels (Vibrio fischeri, Isochrysis galbana, and Paracentrotus lividus). The results of the bioassays at the different times were then considered together with farm water flow in the Potential Ecotoxic Effects Probe (PEEP) index. Despite the high volumes of effluents discharged, the generally low toxicity of the effluents hinders assessment of potentially toxic effects. However, dose-response curves and statistical analysis demonstrated the existence of toxic effects during the first five days of the biodegradation procedure, especially immediately after sampling. The proposed modification of the PEEP index better reflects the changes in toxicity over time. Graphical abstract ᅟ.

Eco- and genotoxicity profiling of a rapeseed biodiesel using a battery of bioassays

Biodiesel is considered an important renewable energy source but still there is some controversy about its environmental toxicity, especially to aquatic life. In our study, the toxicity of water soluble fraction of biodiesel was evaluated in relatively low concentrations using a battery of bioassays: Vibrio fischeri bioluminescence inhibition, Sinapis alba root growth inhibition, Daphnia magna immobilization, boar semen live/dead ratio and DNA fragmentation and Unio pictorum micronucleus test. While the S. alba test indicated nutritive (stimulating) effect of the sample, the biodiesel exerted toxic effect in the aquatic tests. D. magna was the most sensitive with EC50 value of 0.0226%. For genotoxicity assessment, the mussel micronucleus test (MNT) was applied, detecting considerable genotoxic potential of the biodiesel sample: it elucidated micronuclei formation already at low concentration of 3.3%. Although this test has never been employed in biodiesel eco/genotoxicity assessments, it seems a promising tool, based on its appropriate sensitivity, and representativity.

The great biotechnological potential of a marine polychaete: An alliance between toxin and natural fluorescence

The great biotechnological potential of a marine polychaete: An alliance between toxin and natural fluorescence

A bioassay battery for the ecotoxicity assessment of soils conditioned with two different commercial foaming products

Alkylethoxysulfate (AES) surfactants are the main component of most commercial products used for soil conditioning in the excavation industry, in particular as lubricants for mechanized tunnelling. Huge amounts of soil debris are produced during the excavation process and their possible re-use as by-products (e.g. land covering) or discharge as waste is a critical question in civil engineering. There can be an environmental impact from the potential ecotoxicity of the residual chemical mixture occurring in the foam-conditioned excavated soil. Chemical analyses are not able on their own to assess the potential hazards for the ecosystem ascribable to inadequate management of this kind of conditioned soil. Ecotoxicological tests, on the other hand, provide useful overall information about the potential effects of conditioned debris on soil and aquatic biota, including synergic ones, whether or not there is a detailed knowledge of the chemical composition of all the components of the commercial foaming products.In this context, the objective of this work was to evaluate the overall ecotoxicity of excavated soil conditioned with two common foaming products containing sodium lauryl ether sulphate (SLES) as the main component, in order to verify their possible re-use as by-products. For this purpose, two soils with different geopedological characteristics were conditioned with the commercial foaming agents at the concentrations utilised for mechanized tunnelling and then used for microcosm laboratory experiments. Soil sub-samples were collected at different times (0, 7, 14, 28 days) of incubation and soil elutriates were produced to assess the effects of the foaming agents on five test species (Pseudokirchneriella subcapitata, Daphnia magna, Danio rerio, Vibrio fischeri and Lepidium sativum). The results of the tests were then compared with SLES residual concentrations in the elutriates, determined with the MBAS (methylene blue active substances) spectrophotometric method. Finally, the data were combined in a battery index, which proved effective at evaluating the overall ecotoxicity in a real-life situation of two different excavated soils conditioned with the two products analysed.

Assessment of long term ecotoxicity of urban stormwaters using a multigenerational bioassay on Ceriodaphnia dubia: A preliminary study

ABSTRACTStandardized ecotoxicity bioassays show some limits to assess properly long-term residual toxicity of complex mixture of pollutants often present at low concentration, such as stormwaters. Among invertebrate organisms used for ecotoxicity testing, the microcrustacean Ceriodaphnia dubia (C. dubia) is considered as one of the most sensitive, especially regarding reproduction impairment as a toxicity endpoint. Consequently, this work explores the interest to perform a multigenerational assay based on the study of the reproduction of C. dubia to assess long-term ecotoxicity of complex mixture, using stormwater samples. With this in mind, a battery of standardized bioassays (Daphnia magna mobility, Pseudokirchneriella subcapitata population growth, Heterocypris incongruens growth and one generation C. dubia reproduction inhibition assays) was performed in parallel to a three generation C. dubia reproduction inhibition assay on 2 stormwater samples. Results highlighted that while all standardized bioassays failed to reveal residual toxicity in the stormwater samples, the C. dubia multigenerational assay exhibited an higher sensitivity than the previous ones. No adverse effect was observed for the first exposed generation, but an increase in mortality and a reproduction disturbance was obtained in the second and third exposed generation depending of the sample. Further experiments are now needed to optimize the exposure protocol of this multigenerational assay.

Determination of the soil hazardous concentrations of bisphenol A using the species sensitivity approach

This study describes the determination of the species sensitivity distribution (SSD)-based soil hazardous contamination of bisphenol A for environmental risk assessment. We conducted a battery of bioassays, including acute assays using eight species from six different taxonomic groups and chronic assays using five species from four different taxonomic groups. We determined that our dataset satisfied Australia & New Zealand’s guidelines for applying the SSD methodology. Finally, the chronic soil HC5 and HC50 values for bisphenol A were estimated to be 13.7 and 74.7mg/kg soil, respectively, for soil ecosystem protection against chronic exposure using the data generated from this and previous studies. Because the soil standard values of bisphenol A for protection of the soil ecosystem are not currently available, the HC values of bisphenol A that we suggested based on the SSD approach would be applied as fundamental data to establish soil standards of bisphenol A for soil ecosystem protection. To our knowledge, this is the first study reporting the soil hazardous concentration of bisphenol A for environmental risk assessment.

Assessing the environmental quality of sediments from Split coastal area (Croatia) with a battery of cell-based bioassays

A battery of cell-based bioassays, including PLHC-1 cells, zebrafish-Pxr-transfected COS-7 cells and estrogen receptor-recombinant yeast assay (ER-RYA), were applied to detect the presence of bioactive pollutants in sediments collected from Kaštela Bay and Brač Channel (Croatia). Exposure of PLHC-1 cells to the sediment extracts evidenced significant cytotoxicity and presence of CYP1A inducers in sediments collected in Kaštela Bay, near the industrial zone and cargo port of Split. Sediments from this area, which is highly contaminated with PCBs, HCB, DDTs and γ-HCH, also activated the zebrafish Pxr (zfPxr) reporter system. No evidence of estrogenicity was detected for any of the sediments extracts in the ER-RYA assay. Importantly, the battery of in vitro assays identified Kaštela Bay as the area with the higher anthropogenic impact, where sediment-bound pollutants could pose a risk to aquatic organisms. In contrast, sediments from the Brač Channel showed rather low response in the different bioassays.

Evaluation of genotoxic potential in the Velika Morava River Basin in vitro and in situ

The Velika Morava River is the greatest national Serbian river and the significant tributary of the Danube River. The major problems in the Velika Morava River Basin (VMRB) represent untreated industrial and municipal wastewaters. In this study, the level of genotoxic potential at the sites along the VMRB was evaluated by parallel in vitro and in situ approach. Within in vitro testing, genotoxicity of native water samples collected from the sites in VMRB was evaluated by SOS/umuC test on Salmonella typhimurium TA1535/pSK1002 and by the comet assay on HepG2 cells. DNA damage in situ was assessed in bleak (Alburnus alburnus) erythrocytes by the comet (alkaline and Fpg-modified comet) and micronucleus assays. Additionally, the concentration of heavy metals in fish tissue was measured and this data, compiled with the data of the physico-chemical parameters measured in water, was used as a measure of the pollution pressure at the sites.Results showed that applied in vitro tests with native water samples are less sensitive in comparison with in situ tests and should be taken with precaution when making predictions on the status of the ecosystem. Within applied battery of in situ assays differential sensitivity of assays was observed where alkaline comet assay showed the highest potential in differentiation of the sites based on genotoxic potential. Integrated biomarker response showed that usage of the battery of bioassays provides better insight in a genotoxic effects in animals, and consequently, that the holistic approach is more suitable for this type of study.

Environmental risk assessment of triclosan and ibuprofen in marine sediments using individual and sub-individual endpoints

The guidelines for the Environmental Risk Assessment (ERA) of pharmaceuticals and personal care products (PPCP) recommend the use of standard ecotoxicity assays and the assessment of endpoints at the individual level to evaluate potential effects of PPCP on biota. However, effects at the sub-individual level can also affect the ecological fitness of marine organisms chronically exposed to PPCP. The aim of the current study was to evaluate the environmental risk of two PPCP in marine sediments: triclosan (TCS) and ibuprofen (IBU), using sub-individual and developmental endpoints. The environmental levels of TCS and IBU were quantified in marine sediments from the vicinities of the Santos submarine sewage outfall (Santos Bay, São Paulo, Brazil) at 15.14 and 49.0 ng g−1, respectively. A battery (n = 3) of chronic bioassays (embryo-larval development) with a sea urchin (Lytechinus variegatus) and a bivalve (Perna perna) were performed using two exposure conditions: sediment-water interface and elutriates. Moreover, physiological stress through the Neutral Red Retention Time Assay (NRRT) was assessed in the estuarine bivalve Mytella charruana exposed to TCS and IBU spiked sediments. These compounds affected the development of L. variegatus and P. perna (75 ng g−1 for TCS and 15 ng g−1 for IBU), and caused a significant decrease in M. charruana lysosomal membrane stability at environmentally relevant concentrations (0.08 ng g−1 for TCS and 0.15 ng g−1 for IBU). Chemical and ecotoxicological data were integrated and the risk quotient estimated for TCS and IBU were higher than 1.0, indicating a high environmental risk of these compounds in sediments. These are the first data of sediment risk assessment of pharmaceuticals and personal care products of Latin America. In addition, the results suggest that the ERA based only on individual-level and standard toxicity tests may overlook other biological effects that can affect the health of marine organisms exposed to PPCP.

In vitro tools for the toxicological evaluation of sediments and dredged materials: intra- and inter-laboratory comparisons of chemical and bioanalytical methods

The implementation of in vitro bioassays for the screening of dioxin-like compounds (DLCs) into management guidelines of dredged material is of increasing interest to regulators and risk assessors. This study reports on an intra- and inter-laboratory comparison study between four independent laboratories. A bioassay battery consisting of RTL-W1 (7-ethoxy-resorufin-O-deethylase; EROD), H4IIE (micro-EROD), and H4IIE-luc cells was used to assess aryl hydrocarbon receptor-mediated effects of sediments from two major European rivers, differently contaminated with DLCs. Each assay was validated by characterization of its limit of detection (LOD) and quantification (LOQ), z-factor, reproducibility, and repeatability. DLC concentrations were measured using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) and compared to bioassay-specific responses via toxicity equivalents (TEQs) on intra- and inter-laboratory levels. The micro-EROD assay exhibited the best overall performance among the bioassays. It was ranked excellent (z-factor=0.54), reached a repeatability >75%, was highly comparable (r 2=0.87) and reproducible (83%) between two laboratories, and was well correlated (r 2=0.803) with TEQs. Its LOD and LOQ of 0.5 and 0.7pM 2,3,7,8-TCDD, respectively, approached LOQs of HRGC/HRMS measurements. In contrast, cell lines RTL-W1 and H4IIE-luc produced LODs >0.7pM 2,3,7,8-TCDD, LOQs >1.7pM 2,3,7,8-TCDD, and repeatability <70%. Based on the data obtained, the micro-EROD assay is the most favorable bioanalytical tool, and via a micro-EROD-based limit value, it would allow for the assessment of sediment DLC concentrations; thus, it could be considered for the implementation into testing and management guidelines for dredged materials.

Monitoring the ecotoxicity of γ-Al2O3 and Ni/γ-Al2O3 nanomaterials by means of a battery of bioassays

The increasing application of nanoparticles (NPs) to a variety of new technologies has become a matter of concern due to the potential toxicity of these materials. Many questions about the fate of NPs in the environment and the subsequent impact on ecosystems need to be answered. The aim of this work was to evaluate the ecotoxicity of two alumina-based nanoceramics, γ-Al2O3 (NC) and Ni/ γ-Al2O3 (NiNC) by means of three different standardized tests: Biochemical Oxygen Demand (BOD5), bioassay with luminescent bacteria (Vibrio fischeri; Microtox), and bioassay on amphibian larvae (Rhinella arenarum) (AMPHITOX). BOD5 values of a very biodegradable mixture (glucose/glutamic acid) decreased with the addition of NiNC(43.8%) and NC (31.6%) with respect to control samples (52.9%). Microtox test results indicated that NiNC presents higher toxicity than NC, with EC50s values of 16.1% and 29.9% respectively; a reduced toxicity was observed, however, in presence of organic matter, thus obtaining EC50s of 37.8% and 19.4%. The results of AMPHITOX test showed a significant increase in the toxicity of both substances over time, the NiNC toxicity being greater than that of NC. The values of 96h-LC50 and 504h-LC50 determined for NiNC were 1.58 and 0.83mg/L, respectively, and 14.5 and 10.5mg/L for NC samples. Amphibian larvae exhibited collapsed cavities, edema, axial flexures, and behavioral alterations as hyperkinesia and reduced movements. These results evidence the vulnerability of wildlife to xenobiotics and the need to develop specific standardized ecotoxicity tests in order to help environmental sustainability and natural species conservation.

Evaluation of ecotoxicological impact of new pyrrole-derived aminophosphonates using selected bioassay battery.

Six new dimethyl N-arylamino(2-pyrrolyl)methylphosphonates 2a-f were synthesized by the modified aza-Pudovik reaction. Their ecotoxicological impact using battery of bioassay was assessed using Microtox and Ostracodtoxit tests as well as phytotoxicity towards two plants, dicotyledonous radish (Raphanus sativus) and monocotyledonous oat (Avena sativa) following the OECD 208 Guideline. Ecotoxicological properties of compounds 2a-f in aspect of acute and chronic toxicity were evaluated using Heterocypris incongruens and Aliivibrio fisheri tests. The obtained results showed that tested aminophosphonates 2a-f have moderate-to-high phyto- and ecotoxicological impact. They are toxic for both plants but more toxic against dicotyledonous. The investigated compounds showed important ecotoxicity against Heterocypris incongruens crustaceans and Aliivibrio fisheri bacteria. It was found that the substituents of the phenyl ring plays a key role in the degree of toxicity. Results showed that investigated compounds are ecologically toxic and that any of their application should be implemented with care.

An Overview of the Adverse Effects of Heavy Metal Contamination on Fish Health

Rapid industrialization results in the production of huge amounts of solid and/or liquid wastes, which is usually discharged into the nearby water bodies, leading to the damage of the important ecosystems and seafood products. Therefore, the present overview aims to highlight the issue of pollution of aquatic ecosystems and fish health. Heavy metals are widely used in every industrial application; therefore, they form the core group of pollutants of any industrial discharge. Some of the heavy metals such as Fe, Mn, Co, Ni, Cu, Zn and Cr are essential as they form the cofactor for many of the enzymes and also needed in metabolic activities. On the contrary, their exceeding amount is also detrimental to both animals and human beings. Based on the current review, it has been observed that to monitor the health of indicator organism (fish), battery of bioassays or biomarkers are required. In addition to this rationale of using the few selected parameters such as condition indices, bioaccumulation, blood biochemistry, marker enzymes of tissue damage, oxidative stress, genotoxicity and histopathology in describing, the aquatic pollution has also been emphasized. All these parameters are significantly affected by heavy metals and hence proved as useful tools in biomonitoring or toxicity assessment studies. Since fishes are consumed by large mass of population due to their high protein and polyunsaturated fatty acid content, human health is also under danger.

W2476 ameliorates β-cell dysfunction and exerts therapeutic effects in mouse models of diabetes via modulation of the thioredoxin-interacting protein signaling pathway.

Recent evidence shows that high glucose levels recruit carbohydrate response element-binding protein, which binds the promoter of thioredoxin-interacting protein (txnip), thereby regulating its expression in β-cells. Overexpression of txnip not only induces β-cell apoptosis but also reduces insulin production. Thus, the discovery of compounds that either inhibit TXNIP activity or suppress its expression was the focus of the present study. INS-1E cells stably transfected with either a txnip proximal glucose response element connected to a luciferase reporter plasmid (BG73) or full-length txnip promoter connected to a luciferase reporter plasmid (CL108) were used in primary and secondary high-throughput screening campaigns, respectively. From 256 000 synthetic compounds, a small molecule compound, W2476 [9-((1-(4-acetyl-phenyloxy)-ethyl)-2-)adenine], was identified as a modulator of the TXNIP-regulated signaling pathway following the screening and characterized using a battery of bioassays. The preventive and therapeutic properties of W2476 were further examined in streptozotocin-induced diabetic and diet-induced obese mice. Treatment with W2476 (1, 5, and 15 μmol/L) dose-dependently inhibited high glucose-induced TXNIP expression at the mRNA and protein levels in INS-1E cells and rat pancreatic islets. Furthermore, W2476 treatment prevented INS-1E cells from apoptosis induced by chronic exposure of high glucose and enhanced insulin production in vitro. Oral administration of W2476 (200 mg·kg-1·d-1) rescued streptozotocin-induced diabetic mice by promoting β-cell survival and enhancing insulin secretion. This therapeutic property of W2476 was further demonstrated by its ability to improve glucose homeostasis and insulin sensitivity in diet-induced obese mice. Thus, chemical intervention of the TXNIP-regulated signaling pathway might present a viable approach to manage diabetes.