Organochlorine pesticide, endosulfan induced cellular and organismal response in Drosophila melanogaster

Biodetector for chlordane using doped InP3 monolayers: a density functional theory study

Chlordane is a serious pollutant in the environment, and it is necessary to monitor chlordane levels using biodetectors. We performed first-principles calculations to investigate the adsorption of chlordane on Ag, Pd, and Au doped InP3 semiconductor monolayers. The results indicated that the adsorption energies of chlordane adsorbed on Ag, Pd, and Au doped InP3 are -7.961 eV, -6.328 eV, and -7.889 eV respectively. The band gaps of the doped InP3 monolayers underwent drastic changes after coming in contact with chlordane, the largest change in band gap occurred for Pd-doped InP3, where the band gap changed from 0.024 eV to 0.335 eV. The large change in band gap shows that the monolayer is sensitive to the molecule, making it a good biodetector. Our results conclude that Pd-doped InP3 stands out as the most promising biodetector for chlordane. This result will benefit environmental experimentalists in their further research.

Understanding role of pesticides in development of Parkinson's disease: Insights from Drosophila and rodent models

Parkinson's disease is a neurodegenerative illness linked to ageing, marked by the gradual decline of dopaminergic neurons in the midbrain. The exact aetiology of Parkinson's disease (PD) remains uncertain, with genetic predisposition and environmental variables playing significant roles in the disease's frequency. Epidemiological data indicates a possible connection between pesticide exposure and brain degeneration. Specific pesticides have been associated with important characteristics of Parkinson's disease, such as mitochondrial dysfunction, oxidative stress, and α-synuclein aggregation, which are crucial for the advancement of the disease. Recently, many animal models have been developed for Parkinson's disease study. Although these models do not perfectly replicate the disease's pathology, they provide valuable insights that improve our understanding of the condition and the limitations of current treatment methods. Drosophila, in particular, has been useful in studying Parkinson's disease induced by toxins or genetic factors. The review thoroughly analyses many animal models utilised in Parkinson's research, with an emphasis on issues including pesticides, genetic and epigenetic changes, proteasome failure, oxidative damage, α-synuclein inoculation, and mitochondrial dysfunction. The text highlights the important impact of pesticides on the onset of Parkinson's disease (PD) and stresses the need for more research on genetic and mechanistic alterations linked to the condition.

5-Hydroxymethylfurfural mediated developmental toxicity in Drosophila melanogaster

5-hydroxymethylfurfural is a common byproduct in food. However, its effect on growth and development remains incompletely understood. This study investigated the developmental toxicity of 5-HMF to Drosophila larvae. The growth and development of Drosophila melanogaster fed with 5-50 mM 5-HMF was monitored, and its possible mechanism was explored. It was found that 5-HMF prolonged the developmental cycle of Drosophila melanogaster (25 mM and 50 mM). After 5-HMF intake, the level of reactive oxygen species in the third instar larvae increased by 1.23-1.40 fold, which increased the level of malondialdehyde and caused changes in antioxidant enzymes. Moreover, the nuclear factor erythroid-2 related factor 2 antioxidant signaling pathway and the expression of heat shock protein genes were affected. At the same time, 5-HMF disrupted the glucose and lipid metabolism in the third instar larvae, influencing the expression level of key genes in the insulin signal pathway. Furthermore, 5-HMF led to intestinal oxidative stress, and up-regulated the expression of the pro-apoptotic gene, consequently impacting intestinal health. In short, 5-HMF causes oxidative stress, disturbs glucose and lipid metabolism and induces intestinal damage, damaging related signaling pathways, and ultimately affecting the development of Drosophila melanogaster.

Surviving in a multistressor world: Gene expression changes in earthworms exposed to heat, desiccation, and chemicals

An investigation of the effects of anthropogenic stress on terrestrial ecosystems is urgently needed. In this work, we explored how exposure to heat, desiccation, and chemical stress alters the expression of genes that encode heat shock proteins (HSPs), an enzyme that responds to oxidative stress (CAT), hypoxia-related proteins (HIF1 and HYOU), and a DNA repair-related protein (PARP1) in the earthworm Eisenia fetida. Exposure to heat (31°C) for 24 h upregulated HSPs and hypoxia-related genes, suggesting possible acquired thermotolerance. Desiccation showed a similar expression profile; however, the HSP response was activated to a lesser extent. Heat and desiccation activated the small HSP at 24 h, suggesting that they may play a role in adaptation. Simultaneous exposure to endosulfan and temperature for 7 h upregulated all of the evaluated genes, implicating a coordinated response involving multiple biological processes to ensure survival and acclimation. These results highlight the relevance of multistress analysis in terrestrial invertebrates.

Alleviation of arsenic-induced neurobehavioral defects with selenium in the larvae of Zaprionus indianus

Selenium is an essential antioxidative micronutrient. This study was conducted to characterize the arsenic toxicity induced on the African fig fly, Zaprionus indianus, and its possible amelioration by selenium. We used computational tools and in vivo experiments to elucidate the mechanism of action of arsenic and selenium on Z. indianus larvae. We conducted experiments to study neurobehavioral parameters including learning and memory ability test and crawling and contraction assays. Our in silico study revealed twelve primary targets of arsenic trioxide. The gene ontology annotation of primary and secondary targets of arsenic trioxide revealed selenocysteine metabolic processes as one of the most reliable targets. To validate our in silico data, we analyzed the effect of arsenic trioxide on larvae of Z. indianus and tested the possible amelioration by sodium selenite supplementation. Our data demonstrated that the arsenic trioxide deteriorated the learning and memory ability of 2nd instar larvae of Z. indianus and such effect was reversed by sodium selenite supplementation. Furthermore, crawling and contraction assay done on 3rd instar larvae showed that there was reduction in both parameters upon arsenic trioxide exposure, which was restored with sodium selenite supplementation. Altogether, our computational and in vivo results strongly indicated that the neurobehavioral defects induced by arsenic trioxide on the larvae of Z. indianus can be successfully alleviated in the presence of sodium selenite.

Toxicological Profile of Polyethylene Terephthalate (PET) Microplastic in Ingested Drosophila melanogaster (Oregon R+) and Its Adverse Effect on Behavior and Development

Microplastics are readily available in the natural environment. Due to the pervasiveness of microplastic pollution, its effects on living organisms necessitate further investigation. The size, time of exposure, and amount of microplastic particles appear to be the most essential factor in determining their toxicological effects, either organismal or sub-organismal. For our research work, we preferred to work on a terrestrial model organism Drosophila melanogaster (Oregon R+). Therefore, in the present study, we characterized 2-100 µm size PET microplastic and confirmed its accumulation in Drosophila, which allowed us to proceed further in our research work. At larger dosages, research on locomotory activities such as climbing, jumping, and crawling indicated a decline in physiological and neuromuscular functions. Our studies also determined retarded development in flies and decreased survival rate in female flies after exposure to the highest concentration of microplastics. These experimental findings provide insight into the possible potential neurotoxic effects of microplastics and their detrimental effects on the development and growth of flies.

Therapeutic Potential of Green-Engineered ZnO Nanoparticles on Rotenone-Exposed D. melanogaster (Oregon R+): Unveiling Ameliorated Biochemical, Cellular, and Behavioral Parameters

Nanotechnology holds significant ameliorative potential against neurodegenerative diseases, as it can protect the therapeutic substance and allow for its sustained release. In this study, the reducing and capping agents of Urtica dioica (UD), Matricaria chamomilla (MC), and Murraya koenigii (MK) extracts were used to synthesize bio-mediated zinc oxide nanoparticles (ZnO-NPs) against bacteria (Staphylococcus aureus and Escherichia coli) and against rotenone-induced toxicities in D. melanogaster for the first time. Their optical and structural properties were analyzed via FT-IR, DLS, XRD, EDS, SEM, UV-Vis, and zeta potential. The antioxidant and antimicrobial properties of the fabricated ZnO-NPs were evaluated employing cell-free models (DPPH and ABTS) and the well diffusion method, respectively. Rotenone (500 µM) was administered to Drosophila third instar larvae and freshly emerged flies for 24-120 h, either alone or in combination with plant extracts (UD, MC, an MK) and their biogenic ZnO-NPs. A comparative study on the protective effects of synthesized NPs was undertaken against rotenone-induced neurotoxic, cytotoxic, and behavioral alterations using an acetylcholinesterase inhibition assay, dye exclusion test, and locomotor parameters. The findings revealed that among the plant-derived ZnO-NPs, MK-ZnO NPs exhibit strong antimicrobial and antioxidant activities, followed by UD-ZnO NPs and MC-ZnO NPs. In this regard, ethno-nano medicinal therapeutic uses mimic similar effects in D. melanogaster by suppressing oxidative stress by restoring biochemical parameters (AchE and proteotoxicity activity) and lower cellular toxicity. These findings suggest that green-engineered ZnO-NPs have the potential to significantly enhance outcomes, with the promise of effective therapies for neurodegeneration, and could be used as a great alternative for clinical development.

Prospective Subunit Nanovaccine against Mycobacterium tuberculosis Infection─Cubosome Lipid Nanocarriers of Cord Factor, Trehalose 6,6' Dimycolate

An improved vaccine is urgently needed to replace the now more than 100-year-old Bacillus Calmette-Guérin (BCG) vaccine against tuberculosis (TB) disease, which represents a significant burden on global public health. Mycolic acid, or cord factor trehalose 6,6' dimycolate (TDM), a lipid component abundant in the cell wall of the pathogen Mycobacterium tuberculosis (MTB), has been shown to have strong immunostimulatory activity but remains underexplored due to its high toxicity and poor solubility. Herein, we employed a novel strategy to encapsulate TDM within a cubosome lipid nanocarrier as a potential subunit nanovaccine candidate against TB. This strategy not only increased the solubility and reduced the toxicity of TDM but also elicited a protective immune response to control MTB growth in macrophages. Both pre-treatment and concurrent treatment of the TDM encapsulated in lipid monoolein (MO) cubosomes (MO-TDM) (1 mol %) induced a strong proinflammatory cytokine response in MTB-infected macrophages, due to epigenetic changes at the promoters of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) in comparison to the untreated control. Furthermore, treatment with MO-TDM (1 mol %) cubosomes significantly improved antigen processing and presentation capabilities of MTB-infected macrophages to CD4 T cells. The ability of MO-TDM (1 mol %) cubosomes to induce a robust innate and adaptive response in vitro was further supported by a mathematical modeling study predicting the vaccine efficacy in vivo. Overall, these results indicate a strong immunostimulatory effect of TDM when delivered through the lipid nanocarrier, suggesting its potential as a novel TB vaccine.

Protective Role of Hsp27 in the Nonylphenol-Induced Locomotory and Longevity Toxicity

Background Gut health is directly proportional to an organism's fitness. Our recent study showed a functional link between oxidative stress and heat shock protein 27 (Hsp27, a stress protein) in the Drosophila larval gut, which coordinates the nonylphenol (an endocrine disruptor) allied sub-cellular and developmental adversities.

Objective In continuation with the prior study, the present study aimed to explore the association of Hsp27 with locomotory and survival against nonylphenol-induced toxicity in the Drosophila gut.

Methods and Methodology The freshly emerged adult flies were exposed to nonylphenol (5.0 µg/mL) for 10 to 40 days, and their locomotory performance (climbing activity) and survivability were assessed. ANOVA was used to evaluate the statistical significance of the mean values in control and treated flies.

Results Nonylphenol exposure markedly influenced locomotory activity and survivability after 30 to 40 days. For instance, ∼76% (40 days) declined locomotor behavior, and ∼35% (40 days) reduced survivability was observed. While the overexpression of Hsp27 in the organism's gut showed improvement in locomotory performance and survivability after 30 to 40 days. No significant alteration in locomotory performance and survivability was observed after 10 to 20 days of nonylphenol exposure.

Conclusion The present study illustrates that Hsp27 overexpression in the Drosophila gut improves the locomotory performance and survivability in the nonylphenol exposed Drosophila. This also indicates the possible connection between the gut and organismal fitness.

Chronic exposure to the star polycation (SPc) nanocarrier in the larval stage adversely impairs life history traits in Drosophila melanogaster

BACKGROUND

Nanomaterials are widely used as pesticide adjuvants to increase pesticide efficiency and minimize environmental pollution. But it is increasingly recognized that nanocarrier is a double-edged sword, as nanoparticles are emerging as new environmental pollutants. This study aimed to determine the biotoxicity of a widely applied star polycation (SPc) nanocarrier using Drosophila melanogaster, the fruit fly, as an in vivo model.

RESULTS

The lethal concentration 50 (LC₅₀) value of SPc was identified as 2.14 g/L toward third-instar larvae and 26.33 g/L for adults. Chronic exposure to a sub lethal concentration of SPc (1 g/L) in the larval stage showed long-lasting adverse effects on key life history traits. Exposure to SPc at larval stage adversely impacted the lifespan, fertility, climbing ability as well as stresses resistance of emerged adults. RNA-sequencing analysis found that SPc resulted in aberrant expression of genes involved in metabolism, innate immunity, stress response and hormone production in the larvae. Orally administrated SPc nanoparticles were mainly accumulated in intestine cells, while systemic responses were observed.

CONCLUSIONS

These findings indicate that SPc nanoparticles are hazardous to fruit flies at multiple levels, which could help us to develop guidelines for further large-scale application.

Synthesis of Green Engineered Silver Nanoparticles through Urtica dioica: An Inhibition of Microbes and Alleviation of Cellular and Organismal Toxicity in Drosophila melanogaster

Plant fractions have a diversity of biomolecules that can be used to make complicated reactions for the bioactive fabrication of metal nanoparticles (NPs), in addition to being beneficial as antioxidant medications or dietary supplements. The current study shows that Urtica dioica (UD) and biologically synthesized silver nanoparticles (AgNPs) of UD have antibacterial and antioxidant properties against bacteria (Escherichia coli and Pseudomonas putida) and Drosophila melanogaster (Oregon R+). According to their ability to scavenge free radicals, DPPH, ABTS, TFC, and TPC initially estimated the antioxidant potential of UD and UD AgNPs. The fabricated AgNPs were analyzed (UV−Vis, FTIR, EDS, and SEM) to determine the functional groups (alcohol, carboxylic acids, phenol, proteins, and aldehydes) and to observe the shape (agglomerated crystalline and rod-shaped structure). The disc diffusion method was used to test the antimicrobial properties of synthesized Ag-NPs against E. coli and P. putida. For 24 to 120 h, newly enclosed flies and third instar larvae of Drosophila were treated with UD and UD AgNPs. After exposure, tests for biochemical effects (acetylcholinesterase inhibition and protein estimation assays), cytotoxicity (dye exclusion), and behavioral effects (jumping and climbing assays) were conducted. The results showed that nanoparticles were found to have potent antimicrobial activity against all microbial strains tested at various concentrations. In this regard, ethno-medicinal characteristics exhibit a similar impact in D. melanogaster, showing (p < 0.05) significantly decreased cellular toxicity (trypan blue dye), enhanced biochemical markers (AChE efficacy and proteotoxicity), and improved behavioral patterns in the organism treated with UD AgNPs, especially in comparison to UD extract. The results of this study may help in the utilization of specific plants as reliable sources of natural antioxidants that may have been beneficial in the synthesis of metallic NPs, which aids in the production of nanomedicine and other therapeutic applications.

ROS-directed activation of Toll/NF-κB in the hematopoietic niche triggers benzene-induced emergency hematopoiesis

Hematopoietic stem cells/progenitor cells (HSC/HPCs) orchestrate the hematopoietic process, effectively regulated by the hematopoietic niche under normal and stressed conditions. The hematopoietic niche provides various soluble factors which influence the differentiation and self-renewal of HSC/HSPs. Unceasing differentiation/proliferation/high metabolic activity of HSC/HPCs makes them susceptible to damage by environmental toxicants like benzene. Oxidative stress, epigenetic modifications, and DNA damage in the HSC/HPCs are the key factors of benzene-induced hematopoietic injury. However, the role of the hematopoietic niche in benzene-induced hematopoietic injury/response is still void. Therefore, the current study aims to unravel the role of the hematopoietic niche in benzene-induced hematotoxicity using a genetically tractable model, Drosophila melanogaster. The lymph gland is a dedicated hematopoietic organ in Drosophila larvae. A group of 30-45 cells called the posterior signaling center (PSC) in the lymph gland acts as a niche that regulates Drosophila HSC/HPCs maintenance. Benzene exposure to Drosophila larvae (48 h) resulted in aberrant hemocyte production, especially hyper-differentiation of lamellocytes followed by premature lymph gland dispersal and reduced adult emergence upon developmental exposure. Subsequent genetic experiments revealed that benzene-induced lamellocyte production and premature lymph gland dispersal were PSC mediated. The genetic experiments further showed that benzene generates Dual oxidase (Duox)-dependent Reactive Oxygen Species (ROS) in the PSC, activating Toll/NF-κB signaling, which is essential for the aberrant hemocyte production, lymph gland dispersal, and larval survival. Together, the study establishes a functional perspective of the hematopoietic niche in a benzene-induced hematopoietic emergency in a genetic model, Drosophila, which might be relevant to higher organisms.

Toxicity Assessment of Curculigo orchioides Leaf Extract Using Drosophila melanogaster: A Preliminary Study

Curculigo orchioides is used in Indian and Chinese traditional medicinal systems for various health benefits. However, its toxicological effects are mostly unknown. This study assesses the potential toxicity of aqueous leaf (A.L.) extract of C. orchioides using Drosophila melanogaster as an experimental model. Preliminary phytochemical tests were followed by the Fourier transform infrared (FTIR) tests to identify the functional group in the A.L. extract of C. orchioides. Drosophila larvae/adults were exposed to varying concentrations of C. orchioides A.L. extract through diet, and developmental, lifespan, reproduction, and locomotory behaviour assays were carried out to assess the C. orchioides toxicity at organismal levels. The cellular toxicity of A.L. extract was examined by analysing the expression of heat shock protein (hsps), reactive oxygen species (ROS) levels, and cell death. The FTIR analysis showed the presence of functional groups indicating the presence of secondary metabolites like saponins, phenolics, and alkaloids. Exposure to A.L. extract during development resulted in reduced emergence and wing malformations in the emerged fly. Furthermore, a significant reduction in reproductive performance and the organism's lifespan was observed when adult flies were exposed to A.L. extract. This study indicates the adverse effect of C. orchioides A.L. extract on Drosophila and raises concerns about the practice of indiscriminate therapeutic use of plant extracts.

Ethnopharmacological Effects of Urtica dioica, Matricaria chamomilla, and Murraya koenigii on Rotenone-Exposed D. melanogaster: An Attenuation of Cellular, Biochemical, and Organismal Markers

Natural antioxidants derived from plants have been proven to have significant inhibitory effects on the free radicals of living organisms during actively metabolization. Excessive production of free radicals increases the risk of neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and motor sclerosis. This study aimed to compare the ethnopharmacological effects of Urtica dioica (UD), Matricaria chamomilla (MC), and Murraya koenigii (MK) on the amelioration of rotenone-induced toxicity in wild-type Drosophila melanogaster (Oregon R+) at biochemical, cellular, and behavioral levels. Phytoextracts were prepared from all three plants, i.e., UD, MC, and MK (aqueous and ethanolic fractions), and their bioactive compounds were evaluated using in vitro biochemical parameters (DPPH, ABTS, TPC, and TFC), UV-Vis, followed by FT-IR and HPLC. Third instar larvae and freshly eclosed flies were treated with 500 µM rotenone alone or in combination with UD, MC, and MK for 24 to 120 h. Following exposure, cytotoxicity (dye exclusion test), biochemical (protein estimation and acetylcholinesterase inhibition assays), and behavioral assays (climbing and jumping assays) were performed. Among all three plant extracts, MK exhibited the highest antioxidant properties due to the highest TPC, TFC, DPPH, and ABTS, followed by UD, then MC. The overall trend was MK > UD > MC. In this context, ethnopharmacological properties mimic the same effect in Drosophila, exhibiting significantly (p < 0.05) reduced cytotoxicity (trypan blue), improved biochemical parameters (proteotoxicity and AChE activity), and better behavioral parameters in the organisms cotreated with phyto extracts compared with rotenone. Conclusively, UV-Vis, FTIR, and HPLC analyses differentiated the plant extracts. The findings of this research may be beneficial in the use of select herbs as viable sources of phyto-ingredients that could be of interest in nutraceutical development and various clinical applications.

Hsp70 overexpression in Drosophila hemocytes attenuates benzene-induced immune and developmental toxicity via regulating ROS/JNK signaling pathway

Benzene, a ubiquitous environmental chemical, is known to cause immune dysfunction and developmental defects. This study aims to investigate the relation between benzene-induced immune dysfunction and developmental toxicity in a genetically tractable animal model, Drosophila melanogaster. Further, the study explored the protective role of Heat Shock Protein 70 (Hsp70) against benzene-induced immunotoxicity and subsequent developmental impact. Drosophila larvae exposed to benzene (1.0, 10.0, and 100.0 mM) were examined for total hemocyte (immune cells) count, phagocytic activity, oxidative stress, apoptosis, and their developmental delay and reduction were analyzed. Benzene exposure for 48 h reduced the total hemocytes count and phagocytic activity, along with an increase in the Reactive Oxygen Species (ROS), and lipid peroxidation in the larval hemocytes. Subsequently, JNK-dependent activation of the apoptosis (Caspase-3 dependent) was also observed. During their development, benzene exposure to Drosophila larvae led to 3 days of delay in development, and ~40% reduced adult emergence. Hsp70-overexpression in hemocytes was found to mitigate benzene-induced oxidative stress and abrogated the JNK-mediated apoptosis in hemocytes, thus restoring total hemocyte count and improving phagocytotic activity. Further, hsp70-overexpression in hemocytes also lessened the benzene-induced developmental delay (rescue of 2.5 days) and improved adult emergence (~20%) emergence, revealing a possible control of immune cells on the organism's development and survival. Overall, this study established that hsp70-overexpression in the Drosophila hemocytes confers protection against benzene-induced immune injury via regulating the ROS/JNK signaling pathway, which helps in the organism's survival and development.

Systematic toxicity assessment of CdTe quantum dots in Drosophila melanogaster

The risk assessment of cadmium (Cd)-based quantum dots (QDs) used for biomedical nanotechnology applications has stern toxicity concerns. Despite cytotoxicity studies of cadmium telluride (CdTe) QDs, the systematic in vivo study focusing on its organismal effects are more relevant to public health. Therefore, the present study aims to investigate the effect of chemically synthesized 3-mercapto propionic acid-functionalized CdTe QDs on organisms' survival, development, reproduction, and behaviour using Drosophila melanogaster as a model. The sub-cellular impact on the larval gut was also evaluated. First/third instar larvae or the adult Drosophila were exposed orally to green fluorescence emitting CdTe QDs (0.2-100 μM), and organisms' longevity, emergence, reproductive performance, locomotion, and reactive oxygen species (ROS), and cell death were assessed. Uptake of semiconductor CdTe QDs was observed as green fluorescence in the gut. A significant decline in percentage survivability up to 80% was evident at high CdTe QDs concentrations (25 and 100 μM). The developmental toxicity was marked by delayed and reduced fly emergence after CdTe exposure. The teratogenic effect was evident with significant wing deformities at 25 and 100 μM concentrations. However, at the reproductive level, adult flies' fecundity, fertility, and hatchability were highly affected even at low concentrations (1 μM). Surprisingly, the climbing ability of Drosophila was unaffected at any of the used CdTe QDs concentrations. In addition to organismal toxicity, the ROS level and cell death were elevated in gut cells, confirming the sub-cellular toxicity of CdTe QDs. Furthermore, we observed a significant rescue in CdTe QDs-associated developmental, reproductive, and survival adversities when organisms were co-exposed with N-acetyl-cysteine (NAC, an antioxidant) and CdTe QDs. Overall, our findings indicate that the environmental release of aqueously dispersible CdTe QDs raises a long-lasting health concern on the development, reproduction, and survivability of an organism.

Hsp27, a potential EcR target, protects nonylphenol-induced cellular and organismal toxicity in Drosophila melanogaster

Deciphering the potential mechanism of chemical-induced toxicity enables us to alleviate the cellular and organismal dysfunction. The environmental presence of nonylphenol (endocrine disruptor) has a major health concern due to its widespread usage in our day-to-day life. The current study establishes a novel functional link among nonylphenol-induced oxidative stress, Heat shock protein 27 (Hsp27, member of stress protein family), and Ecdysone receptor (EcR, a nuclear receptor), which eventually coordinates the nonylphenol-induced sub-cellular and organismal level toxicity in a genetically tractable model Drosophila melanogaster. Drosophila larvae exposed to nonylphenol (0.05, 0.5 and 5.0 μg/mL) showed a significant decrease in Hsp27 and EcR mRNA levels in the midgut. In concurrence, reactive oxygen species (ROS) levels were increased with a corresponding decline in glutathione (GSH) level and Thioredoxin reductase (TrxR) activity. Increased lipid peroxidation (LPO), protein carbonyl (PC) contents, and cell death were also observed in a correlation with the nonylphenol concentrations. Sub-cellular toxicity poses a negative organismal response, which was evident by delayed larval development and reduced Drosophila emergence. Subsequently, a positive genetic correlation (p < 0.001) between EcR and Hsp27 revealed that nonylphenol-dependent EcR reduction is a possible link for the downregulation of Hsp27. Further, Hsp27 overexpression in midgut cells showed a reduction in nonylphenol-induced intracellular ROS, LPO, PC content, and cell death through the TrxR mediated regenerative pathway and reduced GSH level improving the organismal response to the nonylphenol exposure. Altogether, the study elucidates the potential EcR-Hsp27 molecular interactions in mitigating the nonylphenol-induced cellular and organismal toxicity.

Biochemical evaluation and molecular docking assessment of Cymbopogon citratus as a natural source of acetylcholine esterase (AChE)- targeting insecticides

Acetylcholinesterase (AChE) has been an effective target for insecticide development which is a very important aspect of the global fight against insect-borne diseases. The drastic reduction in the sensitivity of insects to AChE-targeting insecticides like organophosphates and carbamates have increased the need for insecticides of natural origin. In this study, we used Drosophila melanogaster as a model to investigate the insecticidal and AChE inhibitory potentials of Cymbopogon citratus and its bioactive compounds. Flies were exposed to 100 and 200 mg/mL C. citratus leaf extract for a 3-h survival assay followed by 45 min exposure for negative geotaxis and biochemical assays. Molecular docking analysis of 45 bioactive compounds of the plant was conducted against Drosophila melanogaster AChE (DmAChE). Exposure to C. citratus significantly reduced the survival rate of flies throughout the exposure period and this was accompanied by a significant decrease in percentage negative geotaxis, AChE activity, catalase activity, total thiol level and a significant increase in glutathione-S-transferase (GST) activity. The bioactive compounds of C. citratus showed varying levels of binding affinities for the enzyme. (+)-Cymbodiacetal scored highest (−9.407 kcal/mol) followed by proximadiol (−8.253 kcal/mol), geranylacetone (−8.177 kcal/mol), and rutin (−8.148 kcal/mol). The four compounds occupied the same binding pocket and interacted with important active site amino acid residues as the co-crystallized ligand (1qon). These compounds could be responsible for the insecticidal and AChE inhibitory potentials of C. citratus and they could be further explored in the development of AChE-targeting insecticides.

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Cymbopogon citratus reduced the AChE activity, catalase activity, total thiol level in Drosophilia melanogaster.

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The bioactive compounds of Cymbopogon citratus displayed considerable binding affinities for Drosophila melanogaster AChE and the four top-scoring compounds are (+)-Cymbodiacetal, proximadiol, geranylacetone, and rutin.

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(+)-Cymbodiacetal showed the highest binding affinity to AChE (DmAChE).

In pursuit of new anti-malarial candidates: novel synthesized and characterized pyrano-benzodioxepin analogues attenuated Plasmodium berghei replication in malaria-infected mice

Malaria, a parasitic disease, is one of the major causes of morbidity and mortality, particularly in the tropics. Following the increased resistance of the primary causative parasite, Plasmodium sp, to the mainstream drug, artemisinin combination therapies (ACTs), combating malaria incidences, morbidity and mortality have remained elusive. Novel pyrano-benzodioxepin derivatives (DHA-PABA and DHA-LEVO) were synthesized and characterized using Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopies. The compounds were subjected to standard in vivo antimalarial screening (using chloroquine-sensitive strain) in mice, and the toxicity was also determined using a standard assay. The observed elevation in serum alkaline phosphatase and acid phosphatase activity in the untreated and the group administered lower doses of DHA-LEVO is an indication of the hepatic stage of the parasite in the experimental animal, which is accompanied by significant perturbation in the membrane of the hepatocyte leading to leakage of this enzyme out of the liver cells. The semisynthetic pyrano-benzodioxepin derivatives act rapidly by clearing the parasite load from the blood. The novel pyrano-benzodioxepin candidates containing endoperoxide functionality hold promise in the pursuit of new monotherapy drug candidates against the virulent strain of the plasmodium.

Persistent pesticides: effects of endosulfan at the molecular level on the aquatic invertebrate Chironomus riparius

Although banned in multiple areas, due to its persistence in the environment, endosulfan constitutes a significant environmental concern. In this work, fourth instar Chironomus riparius larvae were exposed at environmentally relevant endosulfan concentrations of 0.1, 1, and 10 μg/L for 24 h to analyze the possible effects of this acaricide on gene expression and enzymatic activity. Transcriptional changes were studied through the implementation of a real-time polymerase chain reaction array with 42 genes related to several metabolic pathways (endocrine system, detoxification response, stress response, DNA reparation, and immune system). Moreover, glutathione-S-transferase (GST), phenoloxidase (PO), and acetylcholinesterase (AChE) activities were assessed. The five pathways were differentially altered by endosulfan exposure with significant changes in the E93, Dis, MAPR, Met, InR, GSTd3, GSTt3, MRP1, hsp70, hsp40, hsp24, ATM, PARP, Proph, and Def genes. Besides, all of the measured enzymatic activities were modified, with increased activity of GST, followed by PO and AChE. In summary, the results reflected the effects provoked in C. riparius at molecular level despite the absence of lethality. These data raise concerns about the strong alteration on different metabolic routes despite the low concentrations used. Therefore, new risk assessment strategies should consider include the effects at the sub-organismal level as endpoints in addition to the classical ecologically relevant parameters (such as survival). This endeavor will facilitate a comprehensive evaluation of toxicants in the environment.

Eutrophic status influences the impact of pesticide mixtures and predation on Daphnia pulex populations

Pesticides, nutrients, and ecological stressors such as competition or predation co-occur in freshwater ecosystems impacted by agriculture. The extent to which combinations of these stressors affect aquatic populations and the role of nutrients availability in modulating these responses requires further understanding. In this study, we assessed how pesticides affecting different taxonomic groups and predation influence the response of Daphnia pulex populations under different trophic conditions. An outdoor experiment was designed following a factorial design, with the insecticide chlorpyrifos, the herbicide diuron, and the predation by Notonecta sp. individuals as key stressors. The single impact of each of these stressors, and their binary and tertiary combinations, was evaluated on D. pulex abundance and population structure under mesotrophic and eutrophic conditions for 21 days. Data were analyzed using generalized linear mixed models estimated by means of a novel Bayesian shrinkage technique. Our study shows a significant influence of each of the evaluated stressors on D. pulex abundance; however, the impacts of the herbicide and predation were lower under eutrophic conditions as compared to the mesotrophic ones. We found that binary stressor interactions were generally additive in the mesotrophic scenario, except for the herbicide-predation combination, which resulted in synergistic effects. The impacts of the binary stressor combinations in the eutrophic scenario were classified as antagonistic, except for the insecticide-herbicide combination, which was additive. The tertiary interaction resulted in significant effects on some sampling dates; however, these were rather antagonistic and resembled the most important binary stressor combination in each trophic scenario. Our study shows that the impact of pesticides on freshwater populations depends on the predation pressure, and demonstrates that the combined effect of pesticides and ecological stressors is influenced by the food availability and organism fitness related to the trophic status of freshwater ecosystems.

Environmental toxicants, oxidative stress and health adversities: interventions of phytochemicals

OBJECTIVES

Oxidative stress is the most common factor mediating environmental chemical-induced health adversities. Recently, an exponential rise in the use of phytochemicals as an alternative therapeutics against oxidative stress-mediated diseases has been documented. Due to their free radical quenching property, plant-derived natural products have gained substantial attention as a therapeutic agent in environmental toxicology. The present review aimed to describe the therapeutic role of phytochemicals in mitigating environmental toxicant-mediated sub-cellular and organ toxicities via controlling cellular antioxidant response.

METHODS

The present review has covered the recently related studies, mainly focussing on the free radical scavenging role of phytochemicals in environmental toxicology.

KEY FINDINGS

In vitro and in vivo studies have reported that supplementation of antioxidant-rich compounds can ameliorate the toxicant-induced oxidative stress, thereby improving the health conditions. Improving the cellular antioxidant pool has been considered as a mode of action of phytochemicals. However, the other cellular targets of phytochemicals remain uncertain.

CONCLUSIONS

Knowing the therapeutic value of phytochemicals to mitigate the chemical-induced toxicity is an initial stage; mechanistic understanding needs to decipher for development as therapeutics. Moreover, examining the efficacy of phytochemicals against mixer toxicity and identifying the bioactive molecule are major challenges in the field.

Myorelaxant Effect of the Dysphania ambrosioides Essential Oil on Sus scrofa domesticus Coronary Artery and Its Toxicity in the Drosophila melanogaster Model

PURPOSE

Alternative methods for the use of animals in research have gained increasing importance, due to assessments evaluating the real need for their use and the development of legislation that regulates the subject. The principle of the 3R's (replacement, reduction and refinement) has been an important reference, such that in vitro, ex vivo and cord replacement methods have achieved a prominent place in research.

METHODS

Therefore, due to successful results from studies developed with these methods, the present study aimed to evaluate the myorelaxant effect of the Dysphania ambrosioides essential oil (EODa) using a Sus scrofa domesticus coronary artery model, and the toxicity of both the Dysphania ambrosioides essential oil and its major constituent, α-terpinene, against Drosophila melanogaster in toxicity and negative geotaxis assays.

RESULTS

The EODa relaxed the smooth muscle of swine coronary arteries precontracted with K⁺ and 5-HT in assays using Sus scrofa domesticus coronary arteries. The toxicity results presented LC₅₀ values of 1.546 mg/mL and 2.282 mg/mL for the EODa and α-terpinene, respectively, thus showing the EODa and α-terpinene presented toxicity to these dipterans, with the EODa being more toxic.

CONCLUSIONS

Moreover, the results reveal the possibility of using the EODa in vascular disease studies since it promoted the relaxation of the Sus scrofa domesticus coronary smooth muscle.

Heat shock proteins and antioxidants as mechanisms of response to ivermectin in the dung beetle Euoniticellus intermedius

Ivermectin is the most common antiparasitic drug used in livestock in many regions of the world. Its residues are excreted in dung, threatening non-target fauna such as dung beetles, fundamental for cleaning dung in pastures. However, it is unclear which are the physiological mechanisms used by dung beetles to cope with ivermectin. Here we evaluated experimentally the physiological responses of the dung beetle Euoniticellus intermedius to ivermectin-induced stress. We measured metabolic rates, heat shock protein 70 (Hsp70) expression, antioxidant capacity, and oxidative damage in lipids in both males and females exposed to a sublethal dose. Compared to control beetles, ivermectin-treated males and females had increased metabolic rates. Moreover, ivermectin-treated females increased their expression of Hsp70 whereas males increased their antioxidant capacity. No changes in the levels of oxidative damage to lipids were detected for either sex, suggesting a process of hormesis, such that exposure to a moderate concentration of ivermectin could stimulate the action of a protective mechanism against oxidative stress, that differs between sexes. However, it does not exclude the possibility that damage to other biomolecules might have occurred. Sexual differences in physiological responses can be interpreted as the result of hormonal differences or life-history trade-offs that favor different mechanisms in females and males. Hsps and antioxidants are involved in the physiological response of beetles to ivermectin and may be key in providing resistance to this contaminant in target and non-target species, including dung beetles.

Toxicity of Mangifera Indica aqueous stem bark extract evaluated in drosophila melanogaster used as model organism

BACKGROUND

Mangifera indica has been used for treating health complications with little data on its toxicological impact on survival, geotaxis, reproduction, and the antioxidant system.

METHODS

Total phenol and flavonoid contents were estimated. The ingestion method of exposure (extract was mixed in flies' food) was used. Each concentration was administered per 10g fruit flies diet. 7-day LC₅₀ was determined by exposing 50 flies for 7 days to Mangifera indica concentration ranging from 100mg extract/10g diet to 2000mg extract/10g diet. 28 days survival assay was performed by exposing 50 fruit flies each to 25mg extract/10g diet, 50mg extract/10 diet g, and 100mg extract/10g diet for 28 days. A 6-day short term exposure was also conducted to assess Mangifera indica toxic effect on climbing activity, survival, reproduction, and antioxidant system in Drosophila melanogaster.

RESULTS

Total phenol and flavonoid content were 0.226±0.02 and 0.027±0.05mg/g dry weight of the extract, respectively. There was a significant mortality rate (P<0.05), and the 7-day LC₅₀ was 353mg extract/10g diet. At 25mg extract/10g diet 50mg extract/10g diet and 100mg extract/10g diet, the survival-rate of fruit flies significantly dropped (P<0.05) with arise in Mangifera indica concentration. Short-term exposure also showed a significant reduction (P<0.05) in GST-activity, survival-rate, and emergence of young fruit flies with an increase in concentration. Total thiol, locomotor, AChE, and CAT activities decreased non-significantly (P>0.05).

CONCLUSION

The significant adverse effect of Mangifera indica extract as seen in the decrease in survival rate, the emergence of young flies, climbing, and antioxidant activities of fruit flies suggests its cautious application and use in herbal medicine.

Protective effect of Catharanthus roseus plant extracts against endosulfan and its isomers induced impacts on non-targeted insect model, Drosophila melanogaster and live brain cell imaging

Endosulfan has been recognized as a highly controversial pesticide due to its acute toxicity, potential bioaccumulation, persistency, and long-range atmospheric transport. Several plant extracts act as antioxidant agents against wide-range of pesticide toxicity hazards through the free radicals scavenging properties. Plants' secondary metabolites are considered as efficient protective agents against various cellular toxic injuries. Understanding these properties of botanicals, several researchers currently focused on the detoxification and ameliorative potency of plant extracts against highly toxic chemicals. In our studies, we focused on the endosulfan total and its isomers (alpha and beta) induced changes on Drosophila melanogaster and their ameliorative effects by co-administrated with methanolic and aqueous extracts of Catharanthus roseus whole plant. We selected the 1/5th EC₅₀ concentration of alpha-endosulfan, beta-endosulfan, and endosulfan (total) and co-administrated with 1/50th EC₅₀ concentration of aqueous and methanolic extracts and evaluated their ameliorative effects, in terms of verifying the life stage activities, protein profiling and also by using live brain cells imaging. We finally concluded that, the methanolic and aqueous extracts inhibit the toxic impacts caused by endosulfan and its isomers and also increasing the survival rate of the test organism.

Cadmium mediated redox modulation in germline stem cells homeostasis affects reproductive health of Drosophila males

Maintenance of male germline stem cells (GSCs) homeostasis is crucial for successful reproductive life of adults. New insights gained on dysfunction in stem cell maintenance could be the basis of stem cell dependent ailment during adulthood. Cadmium (Cd), a reported male reproductive toxicant, has been explored inadequately for its impact on male GSCs maintenance. The present study, therefore, has been aimed to evaluate the adverse effect of Cd on the homeostasis of GSCs by using Drosophila testis as an in vivo model. Following developmental exposure of environmentally relevant concentrations of Cd (5.0, 10.0 and 20.0 μg/mL) to Drosophila, we showed that a significantly increased level of reactive oxygen species (ROS) at 20.0 μg/mL of Cd resulted in alteration of GSCs number accompanied by inappropriate differentiation leading to reduced sperm number and eventually poor reproductive performance in exposed organism. Rescuing effect was evident by overexpressing sod in the early germ cell stage. The study suggests that an alteration in GSCs homeostasis due to redox imbalance plays a pivotal role in Cd induced failure in male fertility. The study further advocates for the use of Drosophila as an alternative animal model for in vivo evaluation of male GSCs toxicity with minimal ethical concern.

Pesticide exposure and related health problems among family members of farmworkers in southeast Iran. A case-control study

BACKGROUND

Pesticides used in agriculture are some of the most common pollutants in the world. This study aimed to investigate the effects of Organophosphorus Pesticides (OPPs) and Organochlorine Pesticides (OCPs) on the families of farmworkers in the southeast of Iran.

METHODS

In the present case-control study, 141 family members of farmworkers (as the case group) and 59 family members of non-farmworkers (as the controls) were recruited. Serum levels of OCPs such as α-HCH, β-HCH, γ-HCH, 2,4-DDE, 4,4-DDE, 2,4-DDT, and 4,4-DDT were determined. In addition, erythrocyte acetylcholinesterase (AChE) activity, malondialdehyde (MDA), total antioxidant capacity (TAC), protein carbonyl (PC), nitric oxide (NO) serum levels, arylesterase activity of paraoxonase 1 (PON-1), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity were determined in all participants. Furthermore, distance to farmlands, education, crops, type, and the number of consumed fruits were evaluated for each individual separately.

RESULTS

The erythrocyte AChE activity and serum activities of GPx, SOD, and PON-1 and TAC levels were significantly decreased, whereas the concentration of MDA, PC, NO, and seven OCPs were significantly increased in the farmworkers' families as compared to the controls. Spearman correlation and linear regression suggest that OCPs increase the oxidative stress in farmworkers' family members. Moreover, distance, education, farming precedence, products, and ventilation had significant effects on the OCP levels and increased the odds ratio of OCP levels in farmworkers' families.

CONCLUSION

With regards to the data obtained in this study, it was revealed that OCPs as illegal pesticides and OPPs were higher than expected in the farmworkers' family members. Furthermore, exposure to OCPs and OPPs, apart from the other effects on the body, leads to oxidative stress (OS) that may cause serious diseases in the exposed populations.

Endosulfan exposure alters transcription of genes involved in the detoxification and stress responses in Physella acuta

Endosulfan is a persistent pesticide that has been in use for more than five decades. During this time, it has contaminated soil, air, and water reservoirs worldwide. It is extremely toxic and harmful to beneficial non-target invertebrates, aquatic life, and even humans upon consumption, which is one of the many dangers of this pesticide since it biomagnifies in the food chain. The effects of three endosulfan concentrations (1, 10, and 100 µg/L) on the freshwater snail Physella acuta, an invasive cosmopolitan species, were examined over a week-long exposure period. Alterations in the expression of ten genes related to stress and xenobiotic detoxification were measured against the endogenous controls rpL10 and GAPDH by Real-Time polymerase chain reaction. Four genes are described here for the first time in this species, namely Hsp60, Grp78, GSTk1, and GSTm1. The rest of genes were Hsp90, sHsp16.6, cyp2u1, cyp3a7, cyp4f22, and MRP1. cyp2u1, sHsp16.6, and Grp78 expression were all altered by endosulfan. These results suggest a low pesticide concentration activates the acute response in P. acuta by affecting detoxification and stress responses and alter endoplasmic reticulum function and lipid metabolism. Furthermore, the newly identified genes extend the number of processes and cellular locations that can be analyzed in this organism.

Effect of melatonin on Aβ42 induced changes in the mitochondrial function related to Alzheimer's disease in Drosophila melanogaster

Alzheimers's disease is one of the alarming neurodegenerative disease and it is of global concern.The hallmarks of the disease are the amyloid beta (Aβ) aggregation and presence of neurofibrillary tangles (NFTs). The interaction of Aβ with macromolecular targets affects the normal cellular functions. The amyloid peptide interaction with cellular surfaces may trigger the intracellular cascades of signalling. Interaction of Aβ with mitochondria leads to the generation of free radicals. Many studies have suggested the involvement of mitochondrial dysfunction in Alzheimer's disease. Melatonin prevents mitochondria stress and by means of activating the antioxidant systems it protects the death of neurons. Although the study have been already conducted on Aβ42 infused or injury induced animal models but till date there is no reports of such studies on transgenic model of Drosophila melanogaster. In the present study, we have taken UAS/Gal4 system for the development of transgenic flies that overexpress Aβ42 in the brain of Drosophila. With the help of these transgenic flies we have analyse different experiments like behavioural parameters, oxidative stress parameters and protein expression through western blotting in the presence of melatonin. We have found that melatonin significantly ameliorated the toxicity caused by the Aβ42 overexpression. Thus the present study could be beneficial to find out the role of melatonin in transgenic flies overexpressing human Aβ42.

Chronic exposure to acephate triggers ROS-mediated injuries at organismal and sub-organismal levels of Drosophila melanogaster

The present study demonstrates ROS-mediated organismal and sub-organismal injuries in Drosophila melanogaster following chronic acephate exposure. Larvae and adults of Drosophila were reared on food supplemented with sub-lethal concentrations (1-6 μg mL-1) of acephate (LC50 8.71 μg mL-1). The longevity of the treated adults was reduced to half at 6 μg mL-1 exposure along with declined neuromuscular coordination and physical activities. Apparent developmental defects in the compound eyes were confirmed through the detection of apoptotic lesions in larval eye imaginal discs. The larval gut manifested tissue damage at various sites. Neural and fat cell viability was reduced by ∼1.89- and ∼3.38-fold at 6 μg mL-1 acephate treatment, respectively. A significant reduction in hemocyte viability confirmed the immunotoxic potential of acephate. Nearly 1-3-fold enhancement in the expression of OS markers (MDA, protein carbonyl contents, SOD, catalase and HSP70) in the treated larvae served as evidence of ROS production. The post-treatment increase in CYP450 and GST activities reflects the 'switch-on' states of the phase-I and phase-II detoxification mechanism. The genotoxic potential of acephate was confirmed through alkaline single cell gel electrophoresis. Thus, the findings of the present study validate the fact that besides traditional cholinesterase inhibition, chronic sub-lethal exposure to acephate potentially induces ROS-mediated toxic responses in Drosophila.

Endosulfan causes the alterations of DNA damage response through ATM-p53 signaling pathway in human leukemia cells

Exposure to pesticides results in DNA damage and genomic instability. We previously predicted that endosulfan might be associated with leukemia, but the role of endosulfan in leukemia cells has been unexplored. The aim of this study is to elucidate molecular mechanism of endosulfan-induced DNA damage response in human leukemia cells. We performed endosulfan exposure experiments in K562 cells with varying concentrations of endosulfan for 48 h and found that endosulfan lowered cell viability in a dose-dependent manner. We observed the dramatic DNA damage using comet assay and the increase of micronucleus in 75 μM endosulfan-exposed cells. Endosulfan at 75 μM caused the expression alterations of ATM and DNA repair genes such as FANCD2, and BRCA1/2 at different exposure time points (12, 24, 48 h), which was reversed by ATM inhibitor KU-55933. Endosulfan significantly increased the mRNA expression levels of p53 and GADD45A, and decreased PCNA and XRCC2 at 48 h after exposure. Flow cytometric analysis showed that endosulfan at 50 and 75 μM induced cell cycle G1 arrest, a response attributed to down-regulation of CDK6 and up-regulation of p21. We also observed that endosulfan at 50 and 75 μM induced a considerable percentage of cells to undergo apoptosis, as detected by Annexin-V binding assays. Endosulfan resulted in the activation of caspase-3, and elevated the expression levels of PUMA and the ratio of BAX/Bcl-2. These findings suggest that endosulfan caused DNA damage response throughATM-p53 signaling pathway, implicating the potential correlation between endosulfan and leukemia.

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.

Toxic effects of atrazine on porcine oocytes and possible mechanisms of action

Because atrazine is a widely used herbicide, its adverse effects on the reproductive system have been extensively researched. In this study, we investigated the effects of atrazine exposure on porcine oocyte maturation and the possible mechanisms. Our results showed that the rates of oocyte maturation significantly decreased after treatment with 200 μM atrazine in vitro. Atrazine treatment resulted in abnormal spindle morphology but did not affect actin distribution. Atrazine exposure not only triggered a DNA damage response but also decreased MPF levels in porcine oocytes. Our results also revealed that atrazine worsened porcine oocyte quality by causing excessive accumulation of superoxide radicals, increasing cathepsin B activity, and decreasing the GSH level and mitochondrial membrane potential. Furthermore, atrazine decreased developmental competence of porcine oocytes up to the blastocyst stage and changed some properties: cell numbers, apoptosis, and related gene expression levels. Collectively, our results indicate that porcine oocyte maturation is defective after atrazine treatment at least through disruption of spindle morphology, MPF activity, and mitochondrial function and via induction of DNA damage, which probably reduces developmental competence.

Response of Catalase of the Mouse Primary Hepatocytes to Sodium Dodecylbenzenesulfonate and the Underlying Molecular Mechanisms

This study investigated the adverse effects of sodium dodecylbenzenesulfonates (SDBS) on mouse primary hepatocytes by conducting cell viability, intracellular oxidative stress level, and catalase (CAT) activity assays. It was shown that SDBS altered CAT activities, triggered oxidative stress, and thus exhibited cytotoxicity to the hepatocytes. Both the stimulation of intracellular CAT production and the inhibition of molecular CAT activity contributed to intracellular CAT activity change. Molecular mechanisms underlying CAT activity inhibition and structural changes were explored by isothermal titration calorimetry, multispectroscopy, and molecular docking studies. SDBS binds to CAT with 8.81 ± 0.751 sites via electrostatic forces, resulting in structural changes with α-helix significantly decreasing to 9.7 ± 1.2%. SDBS could interact with HIS 74, ASN 147, and TYR 357 around the active sites as well as TRP 185, ASP 127, and GLN 167 within the substrate channel and therefore might result in the inhibition of molecular CAT activity.

Exploring hazards of acute exposure of Acephate in Drosophila melanogaster and search for l-ascorbic acid mediated defense in it

This study reveals protective role of l-ascorbic acid (25, 50 and 100μg/mL) against toxic impacts of acute sub-lethal exposure of Acephate (5μg/mL) in a non-target organism Drosophila melanogaster. Organismal effect was evident from increased impairment in climbing activities (9 folds) of treated individuals who also manifested altered ocular architecture. These anomalies were reduced with l-ascorbic acid (l-AA) supplementation. Acephate induced apoptotic lesions in eye imaginal discs and gut confirmed tissue damage that also reduced with l-AA co-treatment. Reduction in viability of fat body cells (∼41%), neural cells (∼42%) and hemocytes (3 folds) indicates cytotoxic and immunotoxic potential of Acephate, which were significantly mitigated with l-AA co-administration. The sub-cellular toxic impacts of Acephate treatment became obvious from enhancement in activities of antioxidant enzymes (CAT by ∼1.63 folds, SOD by ∼1.32 folds), detoxifying enzymes (Cyp450 by ∼1.99 folds and GST by ∼1.34 folds), 2.1 times boost in HSP 70 expression, and inhibition of cholinesterase activity (by ∼0.66 folds). DNA breaks evident through comet assay confirmed Acephate triggered genotoxicity which could also be prevented through co-administration of. L-AA Furthermore, the study proposes the use of Drosophila as a model to screen chemicals for their protective potential against pesticide toxicity.

Avermectin induced global DNA hypomethylation and over-expression of heat shock proteins in cardiac tissues of pigeon

Despite increasing evidences pointing to residues of avermectin (AVM) pose toxic effects on non-target organisms in environment, but the data in pigeon is insufficient. The alteration of global DNA methylation and response of heat shock proteins (Hsps) are important for assessing the AVM toxicity in cardiac tissues of pigeon (Columba livia). To investigate the effects of AVM exposure in cardiac tissues of pigeon, we detected the expression levels of DNA methyltransferases (Dnmts), methylated DNA-binding domain protein 2 (MBD2), and Hsp 60, 70 and 90. Pigeons were exposed to feed containing AVM (0, 20, 40 and 60mg/kg diet) for 30, 60, 90days respectively, and cardiac tissues were collected and analyzed. We found the transcriptional levels of Dnmt1, Dnmt3_a and Dnmt3_b mRNA were down-regulated, but the transcriptional levels of MBD2 mRNA were up-regulated by AVM exposure in cardiac tissues of pigeon. Necrocytosis, hemorrhage, infiltration of inflammatory cells and abundant vacuoles appeared in cardiac tissues after AVM exposure. Accompanying this phenotype, the mRNA transcriptional and/or protein levels of Hsp30, Hsp60, Hsp70 and Hsp90 increased. In conclusion, these results underscored AVM exposure caused DNA methylation machinery malfunctions, and induced over-expression of Hsps to improve the protective function against cardiac injury.

Stereoselective toxicity of etoxazole to MCF-7 cells and its dissipation behavior in citrus and soil

The stereoselective cytotoxicity of new chiral acaricide etoxazole and its dissipation in citrus and soil were investigated for the first time. Enantioselective toxicity and oxidative stress of etoxazole toward MCF-7 cells was conducted. The phenomenon of dose- and form-dependent cytotoxicity was demonstrated by MTT and LDH assays, ROS generation, and SOD and CAT activity alternation. Cytotoxicity ranks were found to be consistent with oxidative damage as (R)- > Rac- > (S)-etoxazole. Moreover, the results of enantioselective degradation showed that (S)-etoxazole degraded faster than its antipode (R)-etoxazole. The gradual raise of EF values indicated the achievement of enantioselective degradation in citrus and soil, leaving the enrichment of (R)-etoxazole isomer. Significant differences of environmental behavior and cytotoxicity of etoxazole enantiomers were found in this study which provided valuable insight into the mechanism of potential toxicity and warranted more careful assessment of this pesticide before its agricultural application.

Induction of DNA damage and erroneous repair can explain genomic instability caused by endosulfan

Endosulfan (ES) is an organochlorine pesticide, speculated to be associated with chromosomal abnormalities and diseases in humans. However, very little is known about the mechanism of its genotoxicity. Using in vivo, ex vivo and in vitro model systems, we show that exposure to ES induces reactive oxygen species (ROS) in a concentration and time-dependent manner. The generation of ROS results in DNA double-strand breaks either directly or in a replication-dependent manner, both in mice and human cells. Importantly, ES-induced DNA damage evokes DNA damage response, resulting in elevated levels of classical non-homologous DNA endjoining (NHEJ), the predominant double-strand break repair pathway in higher eukaryotes. Sequence analyses of NHEJ junctions revealed that ES treatment results in extensive processing of broken DNA, culminating in increased and long junctional deletions, thereby favoring erroneous repair. We also find that exposure to ES leads to significant increase in microhomology-mediated end joining (MMEJ), a LIGASE III-dependent alternative repair pathway. Therefore, we demonstrate that ES induces DNA damage and genomic instability, alters DNA damage response thereby promoting erroneous DNA repair.

Role of adipokinetic hormone and adenosine in the anti-stress response in Drosophila melanogaster

The role of adipokinetic hormone (AKH) and adenosine in the anti-stress response was studied in Drosophila melanogaster larvae and adults carrying a mutation in the Akh gene (Akh(1)), the adenosine receptor gene (AdoR(1)), or in both of these genes (Akh(1) AdoR(1) double mutant). Stress was induced by starvation or by the addition of an oxidative stressor paraquat (PQ) to food. Mortality tests revealed that the Akh(1) mutant was the most resistant to starvation, while the AdoR(1) mutant was the most sensitive. Conversely, the Akh(1) AdoR(1) double mutant was more sensitive to PQ toxicity than either of the single mutants. Administration of PQ significantly increased the Drome-AKH level in w(1118) and AdoR(1) larvae; however, this was not accompanied by a simultaneous increase in Akh gene expression. In contrast, PQ significantly increased the expression of the glutathione S-transferase D1 (GstD1) gene. The presence of both a functional adenosine receptor and AKH seem to be important for the proper control of GstD1 gene expression under oxidative stress, however, the latter appears to play more dominant role. On the other hand, differences in glutathione S-transferase (GST) activity among the strains, and between untreated and PQ-treated groups were minimal. In addition, the glutathione level was significantly lower in all untreated AKH- or AdoR-deficient mutant flies as compared with the untreated control w(1118) flies and further declined following treatment with PQ. All oxidative stress characteristics modified by mutations in Akh gene were restored or even improved by 'rescue' mutation in flies which ectopically express Akh. Thus, the results of the present study demonstrate the important roles of AKH and adenosine in the anti-stress response elicited by PQ in a D. melanogaster model, and provide the first evidence for the involvement of adenosine in the anti-oxidative stress response in insects.

Molecular mechanism of catalase activity change under sodium dodecyl sulfate-induced oxidative stress in the mouse primary hepatocytes

Sodium dodecyl sulfate (SDS) contributes to adverse effects of organisms probably because of its ability to induce oxidative stress via changing the activity of antioxidant enzyme catalase (CAT). But the underlying molecular mechanisms still remain unclear. This study characterized the harmful effects of SDS-induced oxidative stress on the mouse primary hepatocytes as well as the structure and function of CAT molecule and investigated the underlying molecular mechanism. After 12h SDS (0.1μM to 0.2mM) exposure, no significant change was observed in CAT activity of the hepatocytes. After 0.5 and 0.8mM SDS exposure, the state of oxidative stress stimulated CAT production in the hepatocytes. The inhibition of CAT activity induced by directly interacting with SDS was unable to catch the synthesis of CAT and therefore resulted in the increased activity and elevated ROS level. Further molecular experiments showed that SDS prefers to bind to the interface with no direct effect on the active site and the structure of heme groups of CAT molecule. When the sites in the interface is saturated, SDS interacts with VAL 73, HIS 74, ASN 147 and PHE 152, the key residues of the enzyme activity, and leads to the decrease of CAT activity.

Unexpected effects of sublethal doses of insecticide on the peripheral olfactory response and sexual behavior in a pest insect

Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive--also called hermetic--effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure.

The Comet assay in insects--Status, prospects and benefits for science

The Comet assay has been recently adapted to investigate DNA damage in insects. The first reports of its use in Drosophila melanogaster appeared in 2002. Since then, the interest in the application of the Comet assay to studies of insects has been rapidly increasing. Many authors see substantial potential in the use of the Comet assay in D. melanogaster for medical toxicology studies. This application could allow the testing of drugs and result in an understanding of the mechanisms of action of toxins, which could significantly influence the limited research that has been performed on vertebrates. The possible perspectives and benefits for science are considered in this review. In the last decade, the use of the Comet assay has been described in insects other than D. melanogaster. Specifically, methods to prepare a cell suspension from insect tissues, which is a difficult task, were analyzed and compared in detail. Furthermore, attention was paid to any differences and modifications in the research protocols, such as the buffer composition and electrophoresis conditions. Various scientific fields in addition to toxicological and ecotoxicological research were considered. We expect the Comet assay to be used in environmental risk assessments and to improve our understanding of many important phenomena of insect life, such as metamorphosis, molting, diapause and quiescence. The use of this method to study species that are of key importance to humans, such as pests and beneficial insects, appears to be highly probable and very promising. The use of the Comet assay for DNA stability testing in insects will most likely rapidly increase in the future.