Genotoxicity Testing of Four Textile Dyes in Two Crosses of Drosophila Using Wing Somatic Mutation and Recombination Test

Exploration of Teratogenic and Genotoxic Effects on Model Organism Drosophila melanogaster

Drosophila melanogaster is one of the crucial in vivo models in terms of analyzing the toxicity of various unknown chemicals. Every part of the fly serves as a model in metabolic and therapeutic approaches. Genotoxic and teratogenic compounds are exposed to Drosophila through the oral route. Further, the toxicity of genotoxic compounds is analyzed in Drosophila's gut, hemolymph, and phenotype. The toxicity of teratogen compounds is also analyzed using a Drosophila embryo. The current chapter summarizes several techniques that are used to detect the genotoxicity and teratogenicity of any unknown compound in this model.

Complex interactions between nicotine and resveratrol in the Drosophila melanogaster wing spot test

Nicotine (NIC) and resveratrol (RES) are chemicals in tobacco and wine, respectively, that are widely consumed concurrently worldwide. NIC is an alkaloid known to be toxic, addictive and to produce oxidative stress, while RES is thought of as an antioxidant with putative health benefits. Oxidative stress can induce genotoxic damage, yet few studies have examined whether NIC is genotoxic in vivo. In vitro studies have shown that RES can ameliorate deleterious effects of NIC. However, RES has been reported to have both antioxidant and pro-oxidant effects, and an in vivo study reported that 0.011 mM RES was genotoxic. We used the Drosophila melanogaster wing spot test to determine whether NIC and RES, first individually and then in combination, were genotoxic and/or altered the cell division. We hypothesized that RES would modulate NIC’s effects. NIC was genotoxic in the standard (ST) cross in a concentration-independent manner, but not genotoxic in the high bioactivation (HB) cross. RES was not genotoxic in either the ST or HB cross at the concentrations tested. We discovered a complex interaction between NIC and RES. Depending on concentration, RES was protective of NIC’s genotoxic damage, RES had no interaction with NIC, or RES had an additive or synergistic effect, increasing NIC’s genotoxic damage. Most NIC, RES, and NIC/RES combinations tested altered the cell division in the ST and HB crosses. Because we used the ST and HB crosses, we demonstrated that genotoxicity and cell division alterations were modulated by the xenobiotic metabolism. These results provide evidence of NIC’s genotoxicity in vivo at specific concentrations. Moreover, NIC’s genotoxicity can be modulated by its interaction with RES in a complex manner, in which their interaction can lead to either increasing NIC’s damage or protecting against it.

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Nicotine was genotoxic at specific concentrations in the Drosophila wing spot test.

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Resveratrol protected against nicotine’s genotoxic effects at some concentrations.

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Resveratrol increased nicotine’s genotoxicity at specific concentrations.

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Nicotine and resveratrol have a complex interaction in vivo.

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Studying chemicals in combination in vivo may uncover unexpected interactions.

Design of laccase-metal-organic framework hybrid constructs for biocatalytic removal of textile dyes

This study aims to present a simple and effective carrier matrix to immobilize laccase as opposed to complex and tedious immobilization processes and also to use it in the removal of textile dyes. For this purpose, Cobalt (Co) and Copper (Cu) based metal-organic frameworks (MOFs) were prepared and laccase was immobilized on two different MOFs via encapsulation. The characterization outcomes showed that laccase was well immobilized into MOF supports. Optimum pH and temperature were found for Lac/Co-MOF (pH 4.5 at 50 °C) and Lac/Cu-MOF (pH 5.0 at 50 °C). The Km (0.03 mM) and Vmax (97.4 μmol/min) values of Lac/Cu-MOF were lower than those of Lac/Co-MOF (Km = 0.13 mM, Vmax = 230.7 μmol/min). The immobilized laccases showed good reusability as well as improved resistance to temperature denaturation and high storage stability. For instance, the Lac/Co-MOF and Lac/Cu-MOF retained more than 58% activity after 4 weeks of storage at room temperature. Meanwhile, Lac/Co-MOF and Lac/Cu-MOF maintained 56.5% and 55.8% of their initial activity, respectively, after 12 reuse cycles. Moreover, thermal deactivation kinetic studies of immobilized laccases displayed lower k value, higher t_1/2, and enhancement of thermodynamic parameters, which means better thermostability. Finally, the decolorization activities for the Lac/Co-MOF were 78% and 61% at the 5th cycle for Reactive Blue 171 and Reactive Blue 198, respectively. In conclusion, it can be inferred that the MOFs are more sustainable and beneficial support for laccase immobilization and they can be efficient for removing textile dyes from industrial wastes.

Drosophila melanogaster Response to Feeding with Neomycin-Based Medium Expressed in Fluctuating Asymmetry

The fruit fly Drosophila melanogaster is a model species used for a wide range of studies. Contamination of Drosophila cultures with bacterial infection is common and is readily eradicated by antibiotics. Neomycin antibiotics can cause stress to D. melanogaster's larvae and imagoes, which may affect the interpretation of the results of research using culture from neomycin-based medium. In the present study, fluctuating asymmetry (FA), one of the important bioindicators of stress, was measured. Larvae and imagoes of a wild-type D. melanogaster strain were exposed to various concentrations of neomycin. The size of anal papillae and selected wing veins were measured using scanning electron and light microscopy, respectively. Next, the FA was checked. The values obtained for larval anal papillae appeared to be concentration-dependant; the FA indices increased with the concentration of neomycin. The wing FA presented a large but variable correlation, depending on the measured vein. However, the mean length of veins was the highest for the control group, with neomycin-exposed groups showing lower values. The research showed that neomycin may cause sublethal stress in D. melanogaster, which manifests in increased FA indices. This suggests that neomycin can cause physiological and developmental stress in insects, which should be taken into account when interpreting the results of studies using these model organisms.

Evaluation of sewage sludge incineration ash as a potential land reclamation material

This study evaluated the potential of utilising sewage sludge incineration ash as a land reclamation material. Toxicity assessment of the leachate of the ash was carried out for both terrestrial and marine organisms. Both the fruit fly Drosophila melanogaster and barnacle Amphibalanus amphitrite showed that both bottom and fly ash leached at liquid-to-solid (L/S) ratio 5 did not substantially affect viabilities. The leachate carried out at L/S 10 was compared to the European Waste Acceptance Criteria and the sewage sludge ashes could be classified as non-hazardous waste. The geotechnical properties of the sewage sludge ash were studied and compared to sand, a conventional land reclamation material, for further evaluation of its potential as a land reclamation material. It was found from direct shear test that both bottom and fly ashes displayed similar and comparable shear strength to that of typical compacted sandy soil based on the range of internal friction angle obtained. However, the consolidation profile of bottom ash was significantly different from sand, while that of fly ash was more similar to sand. Our study showed that the sewage sludge ash has the potential to be used as a land reclamation material.

An insight into the genotoxicity assessment studies in dipterans

The dipterans have been widely utilized in genotoxicity assessment studies. Short life span, easy maintenance, production of large number of offspring in a single generation and the tissues with appropriate cell populations make these flies ideal for studies associated to developmental biology, diseases, genetics, genetic toxicology and stress biology in the group. Moreover, their cosmopolitan presence makes them suitable candidate for ecological bio-monitoring. An attempt has been made in the present review to reveal the significance of dipteran flies for assessing alterations in genetic content through various genotoxicity biomarkers and to summarize the gradual advancement in these studies. Recent studies on genotoxicity assays in dipterans have opened up a broader perspective for DNA repair related mechanistic studies, pre-screening of chemicals and environmental bio-monitoring. Studies in dipterans, other than Drosophila may be helpful in using them as an alternative model system for assessment of genotoxicity, especially at the gene level and further extension of these studies give a future insight to develop new strategies for maintaining environment friendly limits of the toxicants.

The role of natural indigo dye in alleviation of genotoxicity of sodium dithionite as a reducing agent

Indigo blue is a natural dye used for thousands of years by civilizations to dye fabric blue and it is naturally obtained from Isatis tinctoria. I. tinctoria is not only used for extraction of indigo blue color but also used medicinally in Traditional Chinese Medicine because of its active compounds. Sodium dithionite (Na₂S₂O₄) is used in dye bath for indigo blue extraction, but this reducing agent and its derivatives are major pollutants of textile industry and subsequently have hazardous influences on public health. Herein, the present study was designed to obtain the high yield of natural indigo dye but with low possible toxic effect. In this context, genotoxic effects of particular combinations of natural dye solutions obtained from Isatis tinctoria subsp. tomentolla with Na₂S₂O₄ as reducing agent were investigated. Dye solutions were obtained using two different pH levels (pH 9 and 11) and three different concentrations of Na₂S₂O₄ (2.5, 5 and 10 mg/ml). In addition to the dye solutions and reducing agent, aqueous extracts of I. tinctoria were assessed for their genotoxicity on human lymphocytes. For in vitro testing of genotoxicity, chromosomal aberrations (CAs), sister chromatid exchanges (SCEs) and mitotic indexes (MI) assays were used. Accordingly, Na₂S₂O₄ caused significant increases in CA and SCE as well decrease in MI but the genotoxic effects of sodium dithionite were reduced with natural indigo dye. As a result, aqueous extracts of Isatis leaves removed the toxic effects of sodium dithionite and showed anti-genotoxic effect. For the optimal and desired quality but with less toxic effects of natural dye, 2.5 mg/ml (for wool yarn) and 5 mg/ml (for cotton yarn) of Na₂S₂O₄ doses were found to be the best doses for reduction in the dye bath at Ph 9.

Adsorption of cinnabarinic acid from culture fluid with magnetic microbeads

In this study, antimicrobial pigment cinnabarinic acid (CA) was produced from Pycnoporus cinnabarinus in laboratory-scale batch cultures. Magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [m-poly(EGDMA-MATrp)] beads (average diameter = 53-103 µm) were synthesized by copolymerizing of N-methacryloyl-l-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) in the presence of magnetite (Fe3O4) and used for the adsorption of CA. The m-poly(EGDMA-MATrp) beads were characterized by N2 adsorption/desorption isotherms (Brunauer Emmet Teller), X-ray photoelecron spectroscopy, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, electron spin resonance and swelling studies. The efficiency of m-poly(EGDMA-MATrp) beads for separation of CA from culture fluid was evaluated. The effects of pH, initial concentration, contact time and temperature on adsorption were analyzed. The maximum CA adsorption capacity of the m-poly(EGDMA-MATrp) beads was 272.9 mg g(-1) at pH 7.0, 25 °C. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The adsorption process obeyed pseudo-second-order kinetic model. Thermodynamic parameters ΔH = 5.056 kJ mol(-1), ΔS = 52.44 J K(-1)  mol(-1) and ΔG = -9.424 kJ mol-(1) to -11.27 kJ mol-(1) with the rise in temperature from 4 to 40 °C indicated that the adsorption process was endothermic and spontaneous.

Estrogenic and anti-estrogenic activity of 23 commercial textile dyes

The presence of dyes in wastewater effluent of textile industry is well documented. In contrast, the endocrine disrupting effects of these dyes and wastewater effluent have been poorly investigated. Herein, we studied twenty-three commercial dyes, usually used in the textile industry, and extracts of blue jean textile wastewater samples were evaluated for their agonistic and antagonistic estrogen activity. Total estrogenic and anti-estrogenic activities were measured using the Yeast Estrogen Screen bioassay (YES) that evaluates estrogen receptor binding-dependent transcriptional and translational activities. The estrogenic potencies of the dyes and wastewater samples were evaluated by dose-response curves and compared to the dose-response curve of 17β-estradiol (E2), the reference compound. The dose-dependent anti-estrogenic activities of the dyes and wastewater samples were normalized to the known antagonistic effect of 4-hydroxytamoxifen (4-OHT) on the induction of the lac Z reporter gene by E2. About half azo textile dyes have anti-estrogenic activity with the most active being Blue HFRL. Most azo dyes however have no or weak estrogenic activity. E2/dye or E2/waste water ER competitive binding assays show activity of Blue HFRL, benzopurpurine 4B, Everzol Navy Blue FBN, direct red 89 BNL 200% and waste water samples indicating a mechanism of action common to E2. Our results indicate that several textile dyes are potential endocrine disrupting agents. The presence of some of these dyes in textile industry wastewater may thus impact the aquatic ecosystem.

Evaluation of toxicity, genotoxicity and environmental risk of simulated textile and tannery wastewaters with a battery of biotests

Textile and tannery wastewaters are complex mixtures of toxic pollutants and only a battery of ecotoxicity tests can assess their potential environmental impact and the actual effectiveness of alternative treatments. In this work the toxicity of four simulated textile and tannery wastewaters was evaluated by means of a battery of seven bioassays, using organisms that belong to different trophic levels. Moreover, since the outputs of the bioassay battery were quite difficult to compare, a novel synthetic index for environmental risk assessment was applied to the outputs of the test battery. All four simulated wastewaters were very toxic but they showed no mutagenic effect. The alga Pseudokirchneriella subcapitata was the most sensitive organism. In addition, the use of two mathematical models pointed out the interaction effect between dyes and salts, which resulted in a synergistic effect of wastewater toxicity.