sodium-dodecyl-sulfate and 3-4-dichloroaniline

Fish embryos are excellent models for studies aimed at understanding toxic mechanisms and indications of possible acute and chronic effects. For the past 3 yr, an Arabian killifish (Aphanius dispar) fish embryo test has been developed in the authors' laboratory as a routine ecotoxicological test that can be used to support risk assessment of potential contaminants in Arabian Gulf coastal waters. Tests were conducted with 3 reference toxicants (3,4-dichloroaniline [DCA], sodium dodecyl sulfate, and zinc sulfate [Zn]) and chlorine, a disinfectant used widely in industrial cooling systems around the Arabian Gulf region. The 50% effect concentration (EC50) for DCA was 0.47 mg/L and 1.89 mg/L for embryos exposed before 6 hpf and after 168 hpf, respectively. Sublethal effects were mainly observed at concentrations above 2.5 mg/L, the effects included severe pericardial edema and tail shortage. The sodium dodecyl sulfate ionic surfactant caused mortality at both early and late stages of embryo development; it caused coagulation, severe deformity, and hemolysis. Both the EC50 and the 50% lethal concentration (LC50) for sodium dodecyl sulfate were 9.37 mg/L. Salinity influenced the toxicity of Zn to killifish embryos: at 40 psu Zn was found not to be toxic, whereas at 20 psu toxicity had increased significantly (p < 0.05). Values of EC50 and LC50 were 2.5 mg/L and 4 mg/L, respectively. Concentrations above 15 mg/L in embryos were often accompanied by upper abdominal edema and inhibition of growth, especially evident in the tail. Chlorine caused mortality at a lower concentration; for example, at 0.05 mg/L 33% of embryos were found dead at the end of the experiment. The LC50 for chlorine was determined to be 0.08 mg/L. Examination of the existing literature showed similar results to the present study's findings. The results suggest a more comparable sensitivity of killifish embryos to that of other fish embryo test recommended species. The present study's findings support the ability of killifish to be an indicator organism for environmental risk assessments of Arabian Gulf waters. Benefits include sensitivity to a wide range of substances and conditions, animal alternative, ease of fish breeding, and clarity of the embryos.

Topics: Aniline Compounds; Animal Use Alternatives; Animals; Ecotoxicology; Embryo, Nonmammalian; Environmental Monitoring; Fundulidae; Indian Ocean; Lethal Dose 50; Risk Assessment; Seawater; Sodium Dodecyl Sulfate; Water Pollutants, Chemical; Zinc Sulfate

Zebrafish (Danio rerio) is increasingly employed for evaluating toxicity and drug discovery assays. Commonly experimental approaches for biotoxicity assessment are based on visual inspection or video recording. However, these techniques are limited for large-scale assays, as they demand either a time-consuming detailed inspection of the animals or intensive computing resources in order to analyze a considerable amount of screenshots. Recently, we have developed a simple methodology for tracking the locomotor activity of small animals cultured in microtiter plates. In this work, we implemented this automatic methodology, based on infrared (IR) microbeam scattering, for measuring behavioral activity in zebrafish larvae. We determined the appropriate culture conditions, number of animals and stage of development to get robust results. Furthermore, we validated this methodology as a rapid test for evaluating toxicity. By measuring the effects of reference compounds on larvae activity, we were able to estimate the concentration that could cause a 50% decrease in activity events values (AEC₅₀), showing a strong linear correlation (R²  = 0.91) with the LC₅₀ values obtained with the standard DarT test. The toxicity order of the measured compounds was CuSO4  > 2,4-dinitrophenol > 3,4-dichloroaniline > SDS > sodium benzoate > EDTA > K₂CrO4 ; regarding solvents, EtOH ≈ DMSO. In this study, we demonstrate that global swimming behavior could be a simple readout for toxicity, easy to scale-up in automated experiments. This approach is potentially applicable for fast ecotoxicity assays and whole-organism high-throughput compound screening, reducing the time and money required to evaluate unknown samples and to identify leading pharmaceutical compounds.

Topics: 2,4-Dinitrophenol; Aniline Compounds; Animals; Chromates; Copper Sulfate; Dose-Response Relationship, Drug; Ecotoxicology; Edetic Acid; Female; Larva; Lethal Dose 50; Male; Motor Activity; Potassium Compounds; Reproducibility of Results; Scattering, Radiation; Sodium Benzoate; Sodium Dodecyl Sulfate; Toxicity Tests; Zebrafish

Due to the implementation of new legislation, such as REACh, a dramatic increase of animal use for toxicity testing is expected and the search for alternatives is timely. Cell-based in vitro assays are promising alternatives. However, the behavior of chemicals in these assays is still poorly understood. We set out to quantify the exposure and associated toxicity of chemicals with different physicochemical properties toward a fish gill cell line when different solvents and procedural steps are used to introduce test chemicals to cells. Three chemicals with a range of hydrophobicity and volatility were selected and delivered in three different solvents using two common dosing procedures. Toxicity tests were coupled with chemical analysis to quantify the chemical concentrations within culture wells. The impact of solvents and dosing procedure was greatest for the most volatile and hydrophobic test chemical. We show that certain combinations of the test chemical, solvent, and procedural steps can lead to inhomogeneous distribution of the test chemical and thus differing degrees of bioavailability, resulting in quantitative differences in apparent toxicity.

Topics: Aniline Compounds; Animals; Biological Assay; Cell Line; Cell Survival; Chlorobenzenes; Culture Media; Environmental Exposure; Gills; Oncorhynchus mykiss; Sodium Dodecyl Sulfate; Solvents; Toxicity Tests