Fish Danio Rerio Research Articles

Influence of microplastics on the bioconcentration of organic contaminants in fish: Is the “Trojan horse” effect a matter of concern?

Microplastics (MPs) have been shown to act as sorbent phases and thus carriers of organic chemicals in the aquatic environment. Therefore, concerns exist that MP ingestion increases the uptake and accumulation of organic chemicals by aquatic organisms. However, it is unclear if this pathway is relevant compared to other exposure pathways. Here we compared the bioconcentration capacity of two hydrophobic organic chemicals (i.e., chlorpyrifos and hexachlorobenzene) in a freshwater fish (Danio rerio) when exposed to chemicals through water only and in combination with contaminated polyethylene MPs. Additionally, a suite of biomarker analyses (acetylcholine esterase, glutathione S-transferase, alkaline phosphatase, catalase) was carried out to test whether MPs can enhance the toxic stress caused by chemicals. Two 14-day semi-static experiments (one for each chemical) were carried out with adult fish. Each experiment consisted of (1) a control treatment (no chemicals, no MPs); (2) a treatment in which fish were exposed to chlorpyrifos or hexachlorobenzene only through water; (3) a treatment in which fish were exposed to the chemicals through water and contaminated polyethylene MPs (100 mg MP/L). Two additional treatments were included for the biomarker analysis. These contained MPs at two different concentrations (5 and 100 mg MP/L) but no chemicals. The presence of contaminated MPs in contaminated water did not enhance but rather decreased the bioconcentration of both chemicals in fish compared to the treatment that contained contaminated water in absence of MPs. This was more pronounced for hexachlorobenzene, which is more hydrophobic than chlorpyrifos. Enzyme activity levels in fish were only significantly altered in the presence of MPs for alkaline phosphatase. This study indicates that MP presence in freshwater ecosystems is not expected to increase the risks associated with chemical bioconcentration in aquatic organisms and that other exposure pathways (i.e., uptake via respiration, skin permeability) may be of higher importance.

Efficient degradation of emerging organic pollutant by cerium phosphate/g-C3N4/Vis/PMS system: Catalytic kinetics and toxicity evaluation

The Cerium Phosphate (CP) doped g-C3N4(g-CN) composite was synthesized by a simple hydrothermal process. The crystal nature, absorbance, morphology, elemental analysis, functional groups analysis, charge and particle size of all the synthesized materials were examined by various characterization techniques like UV − Vis-DRS spectroscopy (UV–Vis),Fourier transform infra red spectroscopy analysis (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), transmission electron microscopy techniques (TEM), zeta potential and particle size analyser. The characterized CP/g-CN composite was used as a photocatalyst for the degradation of malachite green (Mal G) dye under the visible light irradiation with peroxymonosulfate (PMS) activation. The composite material was found to successfully overcome the electron hole recombination process. The PMS activation process was used to enhance the photocatalytic efficiency of the synthesized CP/g-CN composite. The synthesized CP/g-CN with PMS activation exhibits 94% of malachite green dye degradation in time duration of 90 min and also was found to retain 90% of degradation efficiency after four consecutive photocatalytic performances. The toxicity of the photocatalytic degraded water sample was examined by the animal and plant mortality studies. The zebra fish (Danio rerio) and Mung bean (Vigna radiata) were employed in the animal and plant survival investigations. The CP/g-CN photocatalyst treated dye solution is found to be fit for animal and plant survival and therefore it is a potential photocatalyst for water remediation application.

Insights into Mechanisms of Damage Recognition and Catalysis by APE1-like Enzymes.

Apurinic/apyrimidinic (AP) endonucleases are the key DNA repair enzymes in the base excision repair (BER) pathway, and are responsible for hydrolyzing phosphodiester bonds on the 5′ side of an AP site. The enzymes can recognize not only AP sites but also some types of damaged bases, such as 1,N6-ethenoadenosine, α-adenosine, and 5,6-dihydrouridine. Here, to elucidate the mechanism underlying such a broad substrate specificity as that of AP endonucleases, we performed a computational study of four homologous APE1-like endonucleases: insect (Drosophila melanogaster) Rrp1, amphibian (Xenopus laevis) APE1 (xAPE1), fish (Danio rerio) APE1 (zAPE1), and human APE1 (hAPE1). The contact between the amino acid residues of the active site of each homologous APE1-like enzyme and the set of damaged DNA substrates was analyzed. A comparison of molecular dynamic simulation data with the known catalytic efficiency of these enzymes allowed us to gain a deep insight into the differences in the efficiency of the cleavage of various damaged nucleotides. The obtained data support that the amino acid residues within the “damage recognition” loop containing residues Asn222–Ala230 significantly affect the catalytic-complex formation. Moreover, every damaged nucleotide has its unique position and a specific set of interactions with the amino acid residues of the active site.

Investigating 3R In Vivo Approaches for Bio-Distribution and Efficacy Evaluation of Nucleic Acid Nanocarriers: Studies on Peptide-Mimicking Ionizable Lipid.

Formulations based on ionizable amino-lipids have been put into focus as nucleic acid delivery systems. Recently, the in vitro efficacy of the lipid formulation OH4:DOPE has been explored. However, in vitro performance of nanomedicines cannot correctly predict in vivo efficacy, thereby considerably limiting pre-clinical translation. This is further exacerbated by limited access to mammalian models. The present work proposes to close this gap by investigating in vivo nucleic acid delivery within simpler models, but which still offers physiologically complex environments and also adheres to the 3Rguidelines (replace/reduce/refine) to improve animal experiments. The efficacy of OH4:DOPE as a delivery system for nucleic acids is demonstrated using in vivo approaches. It is shown that the formulation is able to transfect complex tissues using the chicken chorioallantoic membrane model. The efficacy of DNA and mRNA lipoplexes is tested extensively in the zebra fish (Danio rerio) embryo which allows the screening of biodistribution and transfection efficiency. Effective transfection of blood vessel endothelial cells is seen, especially in the endocardium. Both model systems allow an efficacy screening according to the 3R guidelines bypassing the in vitro-in vivo gap. Pilot studies in mice are performed to correlate the efficacy of in vivo transfection.

Meat storage under acoustic freezing conditions and assessment of its biotoxicity (part 2)

The necessity of developing new technologies for refrigerated storage, providing improved quality and safety of meat products, is shown. A critical analysis of cold storage methods has been carried out and the choice of the acoustic freezing method has been substantiated. As a result of the joint work of the students of school No. 2083, “Acoustic Freezing” company and the Institute of Biotechnology and Fisheries, Moscow State University of Technology and Management named after K.G. Razumovsky, studies were carried out to establish the degree of toxicity of pork subjected to refrigeration storage under conditions of shock and acoustic freezing. Histological studies of fresh meat and meat after acoustic and shock freezing have shown that shock freezing leads to a violation of the structure of striated muscles due to the formation of large ice crystals during freezing. The method of fractal analysis of proteins in fresh meat and meat after acoustic freezing showed that the ice crystallization in muscle tissue leads to the formation of different types of fractals. Fractal analysis can be used to select physical factors when improving the technology of acoustic freezing. Toxicological studies were carried out on juvenile clawed frogs Xenopus laevis fed with chironomid larvae, California worms Eisenia fetida (control), fresh meat and meat after acoustic freezing. Studies have shown that there are no significant deviations in the cytological parameters of red blood in frogs eating natural food (worms) and meat after acoustic freezing. Meat after shock freezing is eaten poorly by frogs, which indicates a significant loss of its quality compared to fresh meat. Comparative studies on the effects of feeding fresh meat and meat after acoustic freezing, carried out on the blood of laboratory fish Danio rerio, demonstrated that fresh meat and meat after acoustic freezing do not cause harmful effects on the red blood of fish. The work was carried out within the framework of the program for the introduction of project methods of school education in the secondary school of the Moscow State Budgetary Educational Institution “School No. 2083”.

Viral Vectors in Transgenic Research: Prospects for the Treatment of CNS Diseases and Gene Therapy

Viral vectors are of great clinical interest due to their high efficiency, which allows them to find practical applications in gene therapy. The review presents current research data on various fish species as potential models for the use of viral vectors. During the study of high-performance adenoviral vectors data on the stable expression of transgenes in the body of Danio rerio and other fish species was obtained. The features of the use of adeno-associated vectors in the study of transneuronal transfer of the glucuronidase protein in the projection neurons of the ventral tegmental area and striatum to treat metabolic insufficiency in case of mucopolysaccharidosis VII are considered. Taking into consideration the wide set of genetically modified Danio rerio strains, ethical aspects, and the acceptability of applying this model in neurogenic studies, it is clear that Danio rerio, as well as other fish species, can be used as an alternative for early preclinical evaluation of the efficiency of viral vectors.

Molluscicidal and cercaricidal activities of the essential oil of Dysphania ambrosioides (L.) Mosyakin & Clemants: Implications for the control of schistosomiasis

Schistosomiasis is one of the most important tropical diseases. A fundamental strategy to control its spread is the use of natural products against its vectors, which are snails of the genus Biomphalaria. The present study evaluated the chemical composition, the molluscicidal and cercaricidal effects, and the ecotoxicity of the essential oil from the aerial parts of Dysphania ambrosioides (L.) Mosyakin & Clemants (DAEO). The essential oil was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Molluscicidal and cercaricidal activities were determined by the immersion method. Environmental toxicity was assessed from bioassays using Artemia salina larvae and Danio rerio fish. DAEO presented a 0.8% yield. The GC-MS analysis revealed the predominance of hydrocarbon monoterpenes in the oil. A total of 32 constituents was identified, with α-terpinene (50.69%) being the major compound, followed by p-cymene (13.27%) and ascaridole (10.26%). DAEO was active against adult Biomphalaria glabrata snails and demonstrated lethal effect against Schistosoma mansoni cercariae, with LC50 values of 25.2 (22.7–27.8) and 62.4 (61.8–62.9) μg/mL, respectively. Regarding toxicity to non-target aquatic organisms, the oil showed LC50 values of 86.9 (84.7–87.6) and 18.6 μg/mL (15.5–22.8) for A. salina and D. rerio, respectively. DAEO proved to be a promising natural product for the control of schistosomiasis, acting on both the vectors and the etiological agent of the disease. However, the use of the oil is safer in transmission sites where there are no non-target organisms, as it has showed toxicity to D. rerio fish.

Meat storage under acoustic freezing conditions and assessment of its biotoxicity (part 1)

The necessity of developing new technologies for refrigerated storage, providing improved quality and safety of meat products, is shown. A critical analysis of cold storage methods has been carried out and the choice of the acoustic freezing method has been substantiated. As a result of the joint work of the students of school No. 2083, “Acoustic Freezing” company and the Institute of Biotechnology and Fisheries, Moscow State University of Technology and Management named after K.G. Razumovsky, studies were carried out to establish the degree of toxicity of pork subjected to refrigeration storage under conditions of shock and acoustic freezing. Histological studies of fresh meat and meat after acoustic and shock freezing have shown that shock freezing leads to a violation of the structure of striated muscles due to the formation of large ice crystals during freezing. The method of fractal analysis of proteins in fresh meat and meat after acoustic freezing showed that the ice crystallization in muscle tissue leads to the formation of different types of fractals. Fractal analysis can be used to select physical factors when improving the technology of acoustic freezing. Toxicological studies were carried out on juvenile clawed frogs Xenopus laevis fed with chironomid larvae, California worms Eisenia fetida (control), fresh meat and meat after acoustic freezing. Studies have shown that there are no significant deviations in the cytological parameters of red blood in frogs eating natural food (worms) and meat after acoustic freezing. Meat after shock freezing is eaten poorly by frogs, which indicates a significant loss of its quality compared to fresh meat. Comparative studies on the effects of feeding fresh meat and meat after acoustic freezing, carried out on the blood of laboratory fish Danio rerio, demonstrated that fresh meat and meat after acoustic freezing do not cause harmful effects on the red blood of fish. The work was carried out within the framework of the program for the introduction of project methods of school education in the secondary school of the Moscow State Budgetary Educational Institution “School No. 2083”.

Doublecortin in the Fish Visual System, a Specific Protein of Maturing Neurons.

Simple SummaryDoublecortin (DCX) is an essential protein in the development of the central nervous system and in lamination of the mammalian cortex. It is known that the expression of DCX is restricted to newborn neurons. The visual system of teleost fish has been postulated as an ideal model since it continuously grows throughout the animal’s life. Here, we report a comparative expression analysis of DCX between two teleost fish species as well as a bioinformatic analysis with other animal groups. Our results demonstrate that DCX is very useful for identifying new neurons in the visual systems of Astatotilapia burtoni, but is absent in Danio rerio.Doublecortin (DCX) is a microtubule associated protein, essential for correct central nervous system development and lamination in the mammalian cortex. It has been demonstrated to be expressed in developing—but not in mature—neurons. The teleost visual system is an ideal model to study mechanisms of adult neurogenesis due to its continuous life-long growth. Here, we report immunohistochemical, in silico, and western blot analysis to detect the DCX protein in the visual system of teleost fish. We clearly determined the expression of DCX in newly generated cells in the retina of the cichlid fish Astatotilapia burtoni, but not in the cyprinid fish Danio rerio. Here, we show that DCX is not associated with migrating cells but could be related to axonal growth. This work brings to light the high conservation of DCX sequences between different evolutionary groups, which make it an ideal marker for maturing neurons in various species. The results from different techniques corroborate the absence of DCX expression in zebrafish. In A. burtoni, DCX is very useful for identifying new neurons in the transition zone of the retina. In addition, this marker can be applied to follow axons from maturing neurons through the neural fiber layer, optic nerve head, and optic nerve.

Polycatecholamine and gentamicin as modifiers for antibacterial and blood-biocompatible polyester vascular prostheses

Polyester (PET) prostheses are commonly used in reconstructive vascular surgery. The most serious complication after implantation is early or late infection of the graft. Therefore, there is high demand to protect prosthesis against bacterial adhesion and biofilm development. For this reason, in this work PET prostheses were first coated by highly adhesive polycatecholamine layer. The grafts were then coupled with gentamicin and studied in relation to morphological and structural properties, biological safety (contact with blood, reaction of vascular endothelial cells (HUVEC), Danio rerio fish), drug release and antibacterial activity. Among two tested catecholamine monomers, L-DOPA was found to be more effective precursor in this process than dopamine. For L-DOPA, assistance of Cu2+, Mg2+ and Na+ ions seems to increase the amount of further immobilized drug. Coated prostheses exhibited greater human endothelial cell proliferation increase and lower cytotoxic effect than uncoated. The modification reduced the hemolysis observed for pristine commercial graft and limited the rate of abnormalities in D. rerio larvae, confirming the safety of the proposed modification. The coating allowed to double the amount of immobilized antibiotic in comparison with uncoated graft which resulted in increased antibacterial activity and reduced bacterial adhesion against 4 bacterial strains prevalent in biomaterials infections. Overall, poly(L-DOPA)-coatings deposited on PET vascular grafts can effectively functionalize these prostheses for higher safety in biomedical applications.

Endocrine disruption from plastic pollution and warming interact to increase the energetic cost of growth in a fish.

Energetic cost of growth determines how much food-derived energy is needed to produce a given amount of new biomass and thereby influences energy transduction between trophic levels. Growth and development are regulated by hormones and are therefore sensitive to changes in temperature and environmental endocrine disruption. Here, we show that the endocrine disruptor bisphenol A (BPA) at an environmentally relevant concentration (10 µgl-1) decreased fish (Danio rerio) size at 30°C water temperature. Under the same conditions, it significantly increased metabolic rates and the energetic cost of growth across development. By contrast, BPA decreased the cost of growth at cooler temperatures (24°C). BPA-mediated changes in cost of growth were not associated with mitochondrial efficiency (P/O ratios (i.e. adenosine diphosphate (ADP) used/oxygen consumed) and respiratory control ratios) although BPA did increase mitochondrial proton leak. In females, BPA decreased age at maturity at 24°C but increased it at 30°C, and it decreased the gonadosomatic index suggesting reduced investment into reproduction. Our data reveal a potentially serious emerging problem: increasing water temperatures resulting from climate warming together with endocrine disruption from plastic pollution can impact animal growth efficiency, and hence the dynamics and resilience of animal populations and the services these provide.

Solubility, toxicity, and accumulation of metals from biotite schist rock in Danio rerio fish

Abstract The objective of this work was to determine the solubility of biotite schist rock powder by different methods, as well as the potential toxicity/accumulation of its metals in Danio rerio freshwater fish. Solubility was tested in ultrapure water and in CaCl2 solution (10 mmol L-1). Metal contents were analyzed by inductively coupled plasma optical emission spectroscopy. Fish were separated into different groups and then exposed to biotite schist powder. The solubility of toxic elements in water is not lethal, and, 30 days after the end of exposure, there is no accumulation of metals in the fish.

Zebra fish behavioral assessment by using Calycophyllum spruceanum Bark Methanolic extract

In neurobehavioral research, animal model has played a crucial role in yielding experimental data as well as, in the development of new insights. Researchers are always trying to develop novel animal models to understand fundamental features of physiological, behavioral and psychological disorders. Zebra fish (Danio rerio) is now considered globally as a new and useful model in biomedical research. The objective of the present study was to assess behavioral changes in adult zebra fish after acute exposure to different pharmacological and herbal compound. Adult zebra fish of 4-5-months-old were exposed to different concentrations of unknown test drug with the standard for 5 min. The test was conducted separately for each drug concentration as well as control. Behavioral activity parameters viz. novel tank test and light and dark transition test were recorded for each animal during the exposure period. Results: Zebra fish exposed to Test drug (Calycophyllum spruceanum) showed change in behavioral activity with significant to the standard drug caffeine. In view of the above findings, these results suggested that exposure of adult zebra fish with drug produce the expected changes in the behavior like stress and anxiety; therefore, adult zebra fish can be used an alternative approach for the assessment of new chemical entities for their effect on behavioral activity.

Стан системи антиоксидантного захисту у риб Danio rerio за інтоксикації хлорпірифосом

The article presents the results of studies of acute intoxication in Danio Rerio fish by chlorpyrifos at concentrations 0.5 mg/L; 0.75 mg/L and 1 mg/L of aquarium water for 24 h and its influence on the content of TBK-active products, catalase activity (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPO), glutathione reductase (GR) in their tissues. After 24 h in the fish staying in water with chloropyrifos added in concentrations 0.75 mg/L and 1 mg/L we have revealed an increase of the content of TBK-active products in the studied tissues compared to the control values. The linear nature of the growth of the CAT enzymatic activity in the tissues of head and torso due to the effects of chloropyrifos in doses of 0.5 mg/L; 0.75 mg/L and 1 mg/L. was shown. On the background of the catalase activity growth in Danio rerio, in 24 h after the action of the toxicant, there was an inversely proportional dependence between the dose of chlorpyrifos and the activity of GPOs in both investigated parts of the fish body. In the tissues of the head and torso, inhibition of SOD activity for the action of chlorpyrifos has been established. The activity of this enzyme was the lowest at the chlorpyrifos concentration 0.75 mg/L. The obtained results complement the data on the toxic effect of chlorpyrifos on ichthyofauna and on the course of chlorpyrifos-induced oxidative stress in Danio rerio fish. The obtained data can be used in the development of additional biochemical markers of chlorpyrifos and other phosphor organic compounds intoxication and in toxicological and environmental experiments, taking into account the growing intensity of the use of insecticidal preparations in agricultural production and everyday life.

Toxic Effects of Nanoparticles on Fish Embryos

Nanoparticles are used widely in the in-drug delivery, diagnostics, cosmetics, paints, electronics, fabrics, solar cells, medicines etc. Their wide application is due to their special properties which include minute size, high reaction rate, increased surface area and quantum effect. Despite their multiple applications, nanoparticles have harmful effects too due to their improper disposal causing their entry into the aquatic environment greatly threatening the ecological security as well as our health. Zebra fishes (Danio rerio) are used more commonly for the evaluation of toxicity and are considered a promising animal model. Studies on Salmon and Labeo rohita have also been used for toxicity evaluation. Nanoparticles affect the embryo more easily than the adult since the embryo are more sensitive. Hence it becomes important for us to study the effect of the nanoparticles on the embryo of the fishes. These nanoparticles have the ability to cross the chorion layer and affect the developing embryo. Since the fishes are a part of the food chain, when these organisms get affected they will eventually harm the humans too. This review focuses on the effect of metal nanoparticles (NPs) like gold(Au), silver(Ag), copper(Cu), platinum and metal oxides nanoparticles like titanium dioxide, aluminium oxide, copper oxide, nickel oxide zinc oxide on the embryonic development of fish embryos. When compared to the other nanoparticles (NPs) like silver, copper and platinum, it has been observed that the gold nanoparticles (Au NPs) showed no toxicity to embryos of zebrafish though few studies contradict this. Aluminium nanoparticles showed no toxicity and role of reactive oxygen species (ROS) in enhancing the toxicity of nanoparticles have also been discussed.

Effects of virgin and weathered polystyrene and polypropylene microplastics on Raphidocelis subcapitata and embryos of Danio rerio under environmental concentrations

Microplastics are ubiquitous contaminants of freshwater ecosystems. However, few ecotoxicity assays have been conducted on freshwater organisms using environmentally relevant concentrations of virgin and weathered microplastics. This work assessed the adverse effects of virgin and artificially weathered fragments of polystyrene and polypropylene on the microalga Raphidocelis subcapitata (72 h growth inhibition assay) and on embryos of the fish Danio rerio (96 h fish embryo assay) under environmentally relevant concentrations (2000–200,000 MP L−1) and high concentrations (12.5–100 mg L−1). Sizes of microplastics were measured as tens (polystyrene) to hundreds (polypropylene) of micrometers, while aging was assessed by measuring the carbonyl index. In the microalga, the tested high concentrations promoted growth, while environmentally relevant concentration induced either growth inhibition or promotion. In zebrafish embryos, environmentally relevant concentrations decreased body length and heart rates. No relevant effects were observed in organisms exposed to high concentrations for mortality, malformations, hatching rates, and swimming bladder inflation. Virgin microplastics presented slightly higher toxicity but direct comparison was hindered by the lack of a linear dose-response curve. Despite the lack of a clear pattern, adverse effects were often observed in the lowest environmentally relevant concentrations, raising concerns over the impacts of microplastics on freshwater ecosystems.

Optimization of ozonation process for organic matter and ecotoxicity removal from landfill leachate by applying rotatable central composite design (RCCD)

Ozonation process was used for leachate treatment from a landfill located in Rio de Janeiro, Brazil. The influence of pH and ozone concentration on COD (Chemical Oxygen Demand), TOC (Total Organic Carbon), Absorbance at 254 nm (ABS254nm), and True color was evaluated through RCCD (Rotatable Central Composite Design) experimental design, resulting in mathematical models that were statistically analyzed in Statistica and Design Expert software. The removals obtained was up to 26.1%, 29.9%, 56.9%, and 97.9% for COD ([COD]0=3,323 mg/L), TOC ([TOC]0=1,275 mg/L), ABS254nm (ABS0=32.2), and True color ([True color]0=3,467 mgPt-Co/L), respectively. Statistical and variance analysis of the experimental data revealed that one quadratic model obtained in Statistica was valid, ABS254nm reduction. However, by applying the Design Expert software, modified models were generated to predict the behavior of all dependent variables. Thus, the optimum point for the best response after ozonation of the landfill leachate was at the highest pH and the lowest ozone dose (9 and 2.2 mgO3/m3, respectively). Toxicity toward Allivibrio fischeri bacteria was abated at the same time that it decreased the impact of the effluent to Danio rerio fish (from 125 UT to 62 UT) on the treated leachate.

Novel VOPO4/g-C3N4-PMS system for organic pollutant degradation: Assessment of toxicity by Danio rerio

The hydrothermally synthesized Vanadyl phosphate (VP) was doped with graphitic carbon nitride (g-C3N4) which has low band gap energy and high nitrogen content to form VP/g-C3N4 (VP/GCN) composite. These synthesized materials were aided by PMS activation, and then these materials were evaluated for the photocatalytic degradation of organic Azure B (Az B) dye. The structure and surface morphology of the synthesized materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS), transmission electron microscopy techniques (TEM), UV− Vis-DRS spectroscopy and Fourier transform-infra red spectroscopy (FT-IR) analysis. The photocatalytic degradation of the organic dye was carried out in a photocatalytic chamber under visible light. The PMS activation enhances the catalytic efficiency of the synthesized material. The degradation efficiency of the PMS activated VP/GCN composite was found to be nearly 93% for Az B dye effluent in a time duration of 120 min. The treated effluent water was investigated for the animal survival to understand its toxic nature. VP/GCN composite catalyst treated dye effluent exhibited better survival for zebra fish (Danio rerio) when compared with the untreated dye effluent which clearly proves the VP/GCN catalyst to be an excellent material for water purification.

Combining short-term bioassays using fish and crustacean model organisms with ToxCast in vitro data and broad-spectrum chemical analysis for environmental risk assessment of the river water (Sava, Croatia)

This study focused on the short-term whole organism bioassays (WOBs) on fish (Danio rerio) and crustaceans (Gammarus fossarum and Daphnia magna) to assess the negative biological effects of water from the major European River Sava and the comparison of the obtained results with in vitro toxicity data (ToxCast database) and Risk Quotient (RQ) methodology. Pollution profiles of five sampling sites along the River Sava were assessed by simultaneous chemical analysis of 562 organic contaminants (OCs) of which 476 were detected. At each sampling site, pharmaceuticals/illicit drugs category was mostly represented by their cumulative concentration, followed by categories industrial chemicals, pesticides and hormones. An exposure-activity ratio (EAR) approach based on ToxCast data highlighted steroidal anti-inflammatory drugs, antibiotics, antiepileptics/neuroleptics, industrial chemicals and hormones as compounds with the highest biological potential. Summed EAR-based prediction of toxicity showed a good correlation with the estimated toxicity of assessed sampling sites using WOBs. WOBs did not exhibit increased mortality but caused various sub-lethal biological responses that were dependant relative to the sampling site pollution intensity as well as species sensitivity. Exposure of G. fossarum and D. magna to river water-induced lower feeding rates increased GST activity and TBARS levels. Zebrafish D. rerio embryo exhibited a significant decrease in heartbeat rate, failure in pigmentation formation, as well as inhibition of ABC transporters. Nuclear receptor activation was indicated as the biological target of greatest concern based on the EAR approach. A combined approach of short-term WOBs, with a special emphasis on sub-lethal endpoints, and chemical characterization of water samples compared against in vitro toxicity data from the ToxCast database and RQs can provide a comprehensive insight into the negative effect of pollutants on aquatic organisms.

Acute and Chronic Toxicity of a glyphosate on Danio rerio

Glyphosate herbicides are the most widely produced and used herbicides in the world. The intensive applications of glyphosate and its half-life in water result into many aquatic ecosystems. The present study focuses on the evaluation of glyphosate toxicity on the early life stages of the fish Danio rerio. Analysis of the test results revealed that glyphosate is toxic to zebrafish. This effect is marked by the increase in percent mortality at peak concentrations. Long-term exposure to glyphosate affects the hatching rate, heart rate and swimming ability of zebrafish. Significant malformations were observed at the highest concentration in the form of tail bending or fin absence.