Peumus boldus attenuates copper-induced toxicity in Drosophila melanogaster

Interplay between diphenyl diselenide and copper: Impact on D. melanogaster survival, behavior, and biochemical parameters

Copper (Cu2+) is a biologically essential element that participates in numerous physiological processes. However, elevated concentrations of copper have been associated with cellular oxidative stress and neurodegenerative diseases. Organo‑selenium compounds such as diphenyl diselenide (DPDS) have in vitro and in vivo antioxidant properties. Hence, we hypothesized that DPDS may modulate the toxicity of Cu2+ in Drosophila melanogaster. The acute effects (4 days of exposure) caused by a high concentration of Cu2+ (3 mM) were studied using endpoints of toxicity such as survival and behavior in D. melanogaster. The potential protective effect of low concentration of DPDS (20 μM) against Cu2+ was also investigated. Adult flies aged 1-5 days post-eclosion (both sexes) were divided into four groups: Control, DPDS (20 μM), CuSO4 (3 mM), and the combined exposure of DPDS (20 μM) and CuSO4 (3 mM). Survival, biochemical, and behavioral parameters were determined. Co-exposure of DPDS and CuSO4 increased acetylcholinesterase (AChE) activity and the generation of reactive oxygen species (ROS as determined by DFCH oxidation). Contrary to our expectation, the co-exposure reduced survival, body weight, locomotion, catalase activity, and cell viability in relation to control group. Taken together, DPDS potentiated the Cu2+ toxicity.

Fly into the light: eliminating Drosophila melanogaster with chlorophyllin-based Photodynamic Inactivation

Fruit flies spoil crops in agricultural settings. As conventional pesticides may generate negative off-target effects on humans or the environment, existing treatment methods need eco-friendly and safe alternatives. Photodynamic Inactivation (PDI) is based on the photosensitizer-mediated and light-induced overproduction of reactive oxygen species in targets. We here explore the potential of PDI for the control of fruit fly pests. Drosophila melanogaster serves as well-established model organism in this study. Two distinct experimental approaches are presented: the feed assay, in which fruit flies are provided with sodium magnesium chlorophyllin (Chl, approved as food additive E140) along with sucrose (3%) as their food, and the spray assay, where the photosensitizer is sprayed onto the insects. We show that PDI based on Chl can induce moribundity rates of Drosophila melanogaster of more than 99% with 5 mM Chl and LED illumination (395 nm, 8 h incubation in the dark, radiant exposure 78.9 J/cm2) with the feed assay. If the radiant exposure is doubled to 157.8 J/cm2, 88% of insects are killed by PDI based on 1 mM Chl. The photoactive compound is also effective if presented on strawberries without addition of sucrose with somewhat lower moribundity (71% at 5 mM Chl). Spraying Chl onto insects is less effective than feeding the photosensitizer: 5 mM Chl resulted in 79.5% moribundity (drug to light interval 8 h, radiant exposure 78.9 J/cm2), but if 5 h of sun light (532 J/cm2) and overnight (14 h) dark incubation is used for activation of Chl, more than 95% of insects are killed. As conclusion, Chl serves as effective photoinsecticide against Drosophila melanogaster if a drug to light interval of 8 h is maintained. Feeding the photoactive compound together with sucrose is more effective than spraying it onto insects and increasing the radiant exposure allows for lowering the photosensitizer concentration. Photodynamic Inactivation might therefore represent an eco-friendly addition to the farmers armamentarium against (semi-transparent) insects.

Biological effects of a copper-based fungicide on the fruit fly, Drosophila melanogaster

The increased consumption of pesticides can have a negative environmental impact by increasing the essential metals to toxic levels. Bordasul® is a commonly used fungicide in Brazil and it is composed of 20% Cu, 10% sulfur, and 3.0% calcium. The study of fungicides in vivo in non-target model organisms can predict their environmental impact more broadly. The Drosophila melanogaster is a unique model due to its ease of handling and maintenance. Here, the potential toxicity of Bordasul® was investigated by assessing the development, survival, and behavior of exposed flies. Exposure to Bordasul® impaired the development (p < 0.01) and caused a significant reduction in memory retention (p < 0.05) and locomotor ability (p < 0.001). Fungicides are needed to assure the world's food demand; however, Bordasul® was highly toxic to D. melanogaster. Therefore, Bordasul® may be potentially toxic to non-target invertebrates and new environmentally-safe biofertilizers have to be developed to preserve the biota.

Acute Exposure to Arsenic Affects Pupal Development and Neurological Functions in Drosophila melanogaster

Millions of people in developing countries are affected by arsenic (As) toxicity and its prevalence. Arsenic's detrimental effects on humans have been amplified by an unacceptable level of exposure to food and drinking water, the ongoing rise in industrial usage, and several other occupational conditions. Due to increased cellular absorption and the ability to cross the blood-brain barrier (BBB), inorganic arsenic (iAs) is extremely hazardous to living organisms in its trivalent form. Arsenic toxicity damages an organism's tissues and organs, resulting in skin cancer, circulatory system abnormalities, and central nervous system disorders. However, a competent model system is required to investigate the acute effects of arsenic on the brain, cognition ability, and to assess any behavioral impairment. Hence, Drosophila, with its short generation time, genomic similarities with humans, and its availability for robust behavioral paradigms, may be considered an ideal model for studying arsenic toxicity. The present study helps to understand the toxic effects of acute arsenic treatment on the behavior, cognition, and development of Drosophila in a time-dependent manner. We found that the exposure of fruit flies to arsenic significantly affected their locomotor abilities, pupae size, cognitive functions, and neurobehavioral impairment. Hence, providing a better understanding of how arsenic toxicity affects the brain leading to acute behavioral disorders and neurological alterations, this study will lead to a better understanding of the mechanisms.

Effects of Se-enriched Chrysanthemum morifolium on lifespan and antioxidant defense-related gene expression of Drosophila melanogaster model

Chrysanthemum morifolium is a well-known edible medicinal plant in Asia and some other regions. Content of selenium in Se-enriched C. morifolium (SeCM) is significantly higher than that in traditional C. morifolium (non-Se-enriched C. morifolium, TCM). In order to understand health effects of SeCM, its chemical composition, lifespan-prolonging activities, and impacts on antioxidant defense-related gene expressions of model organism D. melanogaster were systematically studied. A total of eight phenols, including luteolin-7-O-glucoside, linarin, luteolin, apigenin, diosmetin, acacetin, 3-caffeoylquinic acid and 4,5-dicaffeoylquinic acid, were identified in SeCM extract. Compared with TCM, SeCM exhibited superior antioxidant properties. Intake of SeCM dramatically reduced malondialdehyde level and increased activities of endogenous antioxidant enzymes in fruit flies. SeCM was able to upregulate gene expressions of Cu/Zn-superoxide dismutase, Mn-superoxide dismutase and hydrogen peroxide catalase, and extend lifespans of fruit flies. Comparatively high antioxidant capacities and lifespan-prolonging activities of SeCM might be attributed to its abundant phenols and selenium, which probably ameliorated accumulation of free radicals and susceptibility to oxidative stress. These findings provide clues on further exploitation and utilization of Se-enriched C. morifolium. PRACTICAL APPLICATIONS: Chrysanthemum morifolium has been used for nutraceutical and curative purposes in China for thousands of years. Se-enriched C. morifolium typically contains more selenium than traditional C. morifolium, and is widely consumed in Asia and some other regions. Selenium is an essential micronutrient for humans, and selenium deficiency may result in several diseases such as myocardial infarction. SeCM is one of important selenium supplements. In this study, SeCM was found to upregulate gene expressions of Cu/Zn-superoxide dismutase, Mn-superoxide dismutase, and hydrogen peroxide catalase, and extend lifespans of experimental animals. These results provide supporting information for developing SeCM-based functional foods with distinct health benefits.

Toxic metals that interact with thiol groups and alteration in insect behavior

Toxic metals, such as mercury (Hg), lead (Pb), cadmium (Cd), and copper (Cu), are widespread in the biosphere, and human activities have contributed to their continuous release into the ecosystems. Metal-induced toxicity has been extensively studied in mammals; however, the effects of these metals on insects' behavior have been explored to far lesser degree. As the main mechanism of toxicity, the cationic metals, explored in this review, have high affinity for thiol-containing molecules, disrupting the function of several proteins and low-molecular-weight thiol-containing molecules. Existing literature has corroborated that Hg, Pb, Cd, and Cu can disrupt locomotor and mating behaviors, but their effects on insects' memory and learning have yet to be fully characterized. Though field studies on metal-induced toxicity in insects are limited, results from Drosophila melanogaster as an experimental model suggest that insects living in contaminated environments can have behavioral foraging and reproductive deficits, which may cause population decline. In this review, we address the interaction between metals and endogenous thiol groups, with emphasis on alterations in insect behavior.

Biochemical characterization of Peumus boldus fruits: Insights of its antioxidant properties through a theoretical approach

Peumus boldus is an endemic tree species from Chile whose leaves have been the focus of study for decades given that their infusions are reported to relieve rheumatic symptoms, headache, dyspepsia, urinary tract inflammation, and symptoms of other illnesses. These health properties have been studied mainly using leaves and bark, then it is relevant to know more about these properties in different parts of the plant. Considering the importance of P. boldus fruits in the diet of some rural populations, we analyzed their properties to explore its impact on the Chilean population health. Liquid chromatography and mass spectrometry analysis confirmed the presence of alkaloids such as boldine, although aporphine N-methyl-laurotetanine was the most abundant. In addition, flavonoids catechin, chrysin and quercetin were also found in the extract. Cytotoxicity and anti-inflammatory activities of the fruit extract were invitro tested by using a murine macrophage cell model, observing that a diluted fraction of the extract was not cytotoxic, but showed anti-inflammatory activity, which is likely attributed to antioxidants activities. By means of quantum chemical calculations, we calculated the redox potential of the respective alkaloids and flavonoids found in the extract. Results suggest a synergistic effect between alkaloids and flavonoids, where boldine and N-methyl-laurotetanine showed similar antioxidant properties. Finally, we present a description of the oxidation mechanisms for both groups of molecules which will sustain P. boldus fruit biological properties, in order to give this kind of fruits scientific value focusing on human health.

Assessment of Insecticidal Activity of Benzylisoquinoline Alkaloids from Chilean Rhamnaceae Plants against Fruit-Fly Drosophila melanogaster and the Lepidopteran Crop Pest Cydia pomonella

The Chilean plants Discaria chacaye, Talguenea quinquenervia (Rhamnaceae), Peumus boldus (Monimiaceae), and Cryptocarya alba (Lauraceae) were evaluated against Codling moth: Cydia pomonella L. (Lepidoptera: Tortricidae) and fruit fly Drosophila melanogaster (Diptera: Drosophilidae), which is one of the most widespread and destructive primary pests of Prunus (plums, cherries, peaches, nectarines, apricots, almonds), pear, walnuts, and chestnuts, among other. Four benzylisoquinoline alkaloids (coclaurine, laurolitsine, boldine, and pukateine) were isolated from the above mentioned plant species and evaluated regarding their insecticidal activity against the codling moth and fruit fly. The results showed that these alkaloids possess acute and chronic insecticidal effects. The most relevant effect was observed at 10 µg/mL against D. melanogaster and at 50 µg/mL against C. pomonella, being the alteration of the feeding, deformations, failure in the displacement of the larvae in the feeding medium of D. melanogaster, and mortality visible effects. In addition, the docking results show that these type of alkaloids present a good interaction with octopamine and ecdysone receptor showing a possible action mechanism.

D-Penicillamine prolongs survival and lessens copper-induced toxicity in Drosophila melanogaster

D-penicillamine (DPA) is an amino-thiol that has been established as a copper chelating agent for the treatment of Wilson's disease. DPA reacts with metals to form complexes and/or chelates. Here, we investigated the survival rate extension capacity and modulatory role of DPA on Cu²⁺-induced toxicity in Drosophila melanogaster. Adult Wild type (Harwich strain) flies were exposed to Cu²⁺ (1 mM) and/or DPA (50 μM) in the diet for 7 days. Additionally, flies were exposed to acute Cu²⁺ (10 mM) for 24 h, followed by DPA (50 μM) treatment for 4 days. Thereafter, the antioxidant status [total thiol (T-SH) and glutathione (GSH) levels and glutathione S-transferase and catalase activities] as well as hydrogen peroxide (H₂O₂) level and acetylcholinesterase activity were evaluated. The results showed that DPA treatment prolongs the survival rate of D. melanogaster by protecting against Cu²⁺-induced lethality. Further, DPA restored Cu²⁺-induced depletion of T-SH level compared to the control (P < 0.05). DPA also protected against Cu²⁺ (1 mM)-induced inhibition of catalase activity. In addition, DPA ameliorated Cu²⁺-induced elevation of acetylcholinesterase activity in the flies. The study may therefore have health implications in neurodegenerative diseases involving oxidative stress such as Alzheimer's disease.

Metabolic aspects of phenolic compounds from Triplaris gardneriana seeds in the management of oxidative stress

Objective: Considering the limited number of studies that analyze the behavior of plant preparations in human body, this study aimed to characterize the phenolic compounds from Triplaris gardneriana extract (EETg) in terms of antioxidant and metabolic aspects, integrating in vitro, in silico and in vivo strategies.Methods: EETg was analyzed in relation to polyphenols release from the plant matrix under in vitro digestion, as well as the pharmacokinetic prediction of their major compounds by in silico simulation and understanding of its in vivo antioxidant effect in an alternative animal model.Results: About 35.22% of polyphenols from EETg proved to be accessible after enzymatic hydrolysis. A kinetics study showed that 40% of the total content of these phytochemicals was released from the extract accompanied by increased antioxidant capacity after 180 min of gastrointestinal simulation. A computational approach revealed that 7 out of 9 major phenolic compounds of EETg showed good pharmacokinetic parameters such as intestinal absorption and bioavailability score. In addition, the extract showed a protective effect on copper-induced oxidative stress in Drosophila melanogaster, evidenced by the restoration of basal levels of thiol and malondialdehyde contents. These biochemical observations were supported by the examination of histological features of D. melanogaster brain.Conclusion: It was demonstrated that the oral administration of EETg would provide phenolic compounds partially absorbable by the human gut and capable of providing health benefits associated with the inhibition of oxidative stress. Additionally, the results highlight the need to implement new approaches for the rational development of plant-based medicines.

Curcumin attenuates copper-induced oxidative stress and neurotoxicity in Drosophila melanogaster

Curcumin is a hydrophobic polyphenol derived from the rhizome of the Herb Curcuma longa belonging to the family Zingiberaceae. Curcumin possesses antioxidative, anti-inflammatory and anti-depressant-like properties. In this study, we evaluated the rescue role of Curcumin in Copper²⁺-induced toxicity in D. melanogaster. Adult, wild type flies were exposed to Cu²⁺ (1 mM) and/or Curcumin (0.2 and 0.5 mg/kg diet) in the diet for 7 days. The results indicated that Cu²⁺- fed flies had reduced survival compared to the control group. Copper toxicity was also associated with a marked decrease in total thiol (T-SH), as well as catalase and glutathione S-transferase activities, contemporaneous with increased acetylcholinesterase (AChE) activity, nitric oxide (nitrate and nitrite) and dopamine levels. Co-exposure of flies to Cu²⁺ and Curcumin prevented mortality, inhibited AChE activity and restored dopamine to normal levels (p < 0.05). Moreover, Curcumin restored eclosion rates, and the cellular antioxidant status, as well as alleviated the accumulation of nitric oxide level in the flies. Curcumin ameliorated oxidative damage in the flies as evidenced by the survival rates, longevity assay as well as the restoration of antioxidant status. Our findings thus suggest that Curcumin ameliorated Cu²⁺-induced neurotoxicity in D. melanogaster and as such could be considered an effective therapeutic agent in the prevention and treatment of disorders, where oxidative stress is implicated.

Assessing the toxicant effect of spontaneously volatilized 4-vinylcyclohexane exposure in nymphs of the lobster cockroach nauphoeta cinerea

Vinylcyclohexene (VCH) is an environmental contaminant well known for its ovotoxicant effects in several organisms. However, the mechanisms underlying the toxicity of VCH as well as its harmful effects toward other organs are until unclear. In this work, we assess some endpoint signals of toxicity induced by volatilized VCH exposure using nymphs of the lobster cockroach Nauphoeta cinerea. Nymphs were exposed to VCH via inhalation for 70 days. The levels of volatilized VCH were quantified by headspace gas chromatography and the concentration varied between 3.41 and 7.03 nmol/μl. VCH inhalation caused a reduction of 35% in the survival rate of the exposed animals. Nymphs exposed to volatilized VCH for 35 and 70 days had a reduction in the body weight gain of 1.8- and 2.6-fold, respectively with a reduction in dissected head, fat body, and maturing reproductive organs. The exposure did not change water consumption, excepting on the 20th day (with a 3-fold change) and decreased the food intake significantly. Regarding biochemical markers, we found that the activity of GST from the dissected organs was increased by volatilized VCH after both 35 and 70 days of exposure. The fat body presented the most prominent GST activity especially after 35 days of exposure with 1.6-fold higher than the control group. Exposure also caused an increase in RS levels in the fat body of 1.35-fold and 1.47-fold after 35 and 70 days, respectively and did not affect the activity of the AChE from the head. Our findings support the harmful impact of volatilized VCH inhalation, highlighting the cockroach N.cinerea as a valuable insect model to investigate environmental toxicants.

Pequi enriched diets protect Drosophila melanogaster against paraquat-induced locomotor deficits and oxidative stress

The species Caryocar coriaceum Wittm (C. coriaceum), is popularly employed in northeast of Brazil for culinary purposes and in folk medicine. The oil from its fruit, deignated Pequi, is commonly used to treat inflammatory problems, and its leaves to treat viral infections. However, comprehensive knowledge regarding the pharmacological properties attributed to these plant parts is still scarce. Thus, this study aimed to explore the in vivo antioxidant potential of aqueous extract of the leaves (AEL) and Pequi pulp oil (PPO) on the pro-oxidative effects induced by paraquat (PQ) using Drosophila melanogaster (D. melanogaster) as a model. These flies were fed with either standard or AEL and PPO supplemented diets prior to (pre-treatment for 7 days) or concomitantly (co-treatment for 5 days) with PQ. D. melanogaster administered PQ exhibited locomotor deficits and a higher rate of mortality. PQ induced significant changes in the antioxidant/oxidant status of D. melanogaster, including significant (1) increase in levels of reactive oxygen species (ROS) and lipid peroxidation; (2) elevation in the activity of antioxidant enzymes catalase (CAT) and glutathione-S-transferase (GST) and marked up-regulation in mRNA expression of stress-related genes for CAT, superoxide dismutase (SOD), thioredoxin reductase and Keap-1. Aside for mortality rates, AEL and PPO treatments reduced PQ-induced oxidative stress and motor impairments. No apparent evidence of toxicity was observed in D. melanogaster fed with AEL and PPO alone. Our findings provide evidence that AEL and PPO may confer protection against oxidant conditions by stimulating antioxidant responses.

Biocontrol of phytobacteria with bacteriophage cocktails

Crop loss due to plant pathogens has provoked renewed interest in bacteriophages as a feasible biocontrol strategy of plant diseases. Phage cocktails in particular present a viable option for broadening the phage host range, limiting the emergence of bacterial resistance while maintaining the lytic activity of the phages. It is therefore important that the design used to formulate a phage cocktail should result in the most effective cocktail against the pathogen. It is also critical that certain factors are considered during the formulation and application of a phage cocktail: their stability, the production time and cost of complex cocktails, the potential impact on untargeted bacteria, the timing of phage application, and the persistence in the plant environment. Continuous monitoring is required to ensure that the efficacy of a cocktail is sustained due to the dynamic nature of phages. Although phage cocktails are considered as a plausible biocontrol strategy of phytobacteria, more research needs to be done to understand the complex interaction between phages and bacteria in the plant environment, and to overcome the technical obstacles. © 2019 Society of Chemical Industry.

Biochemical CuSO4 Toxicity in Drosophila melanogaster Depends on Sex and Developmental Stage of Exposure

Copper is a transition metal that exists in different chemical forms (e.g., Cu²⁺,Cu⁺, and Cu⁰) and at high concentrations it is toxic. Here, we investigated the Cu²⁺-induced toxicity in Drosophila melanogaster, evaluating the survival, locomotion, and the activity of acetylcholinesterase (AChE) and glutathione S-transferase (GST) enzymes. Flies were exposed to Cu²⁺(0.1-1 mmol CuSO₄/kg of diet or approximately 0.1-1 mM Cu²⁺) and allowed to mate during 24 h. GST and AChE enzymes were evaluated in the larvae and in the head and the body (thorax + abdomen) of the adult male and females flies. The total number of adult females (0.4-1 mM) and males (0.75 and 1 mM) was decreased by CuSO₄. The climbing ability was hampered in flies exposed to 1 mM Cu²⁺. In larvae, Cu²⁺(0.4-1 mM) increased AChE activity (P < 0.002). In males' heads, 0.4 mM Cu²⁺ increased the AChE activity (P < 0.01). In adults' bodies, Cu²⁺inhibited the activity in both sexes, but with greater effectiveness in males (0.1 to 1 mM) than in females (1 mM). Regarding GST activity, 0.1 mM Cu²⁺increased, but 1 mM decrease GST in larvae. In the head of flies, Cu²⁺decreased the GST activity at intermediate (0.4 mM) and increased GST at the highest concentration (1 mM) in males. In the bodies, the effect of Cu²⁺was similar. In conclusion, Cu²⁺exposure in D. melanogaster disrupted locomotion and enzymatic parameters that can be related to changes in AChE and in the detoxifying GST enzyme.

Neuroprotective effects of dietary borax in the brain tissue of rainbow trout (Oncorhynchus mykiss) exposed to copper-induced toxicity

We aimed to investigate the modulating effects of dietary borax on the pathways in rainbow trout brain exposed to copper. For this aim, a comprehensive assessment was performed including biochemical (acetylcholinesterase (AChE), malondialdehyde (MDA), oxidative DNA damage (8-hydroxy-2'-deoxyguanosine (8-OHdG), and caspase-3 levels) and transcriptional parameters (heat shock protein 70 (HSP70) and cytochromes P450 (CYP1A), glutathione peroxidase (gpx), superoxide dismutase (sod), and catalase (cat)) parameters and immunohistochemically staining of 8-OHdG. Special fish feed diets were prepared for the trial. These diets contained different concentrations of borax (1.25, 2.5, and 5 mg/kg) and/or copper (500 and 1000 mg/kg) at the period of pre- and co-treatment strategies for 21 days. At the end of the treatment periods, brain tissue was sampled for each experimental group. As a result, the biochemical parameters were increased and AChE activity decreased in the copper and copper-combined groups in comparison with the control group and also with only borax applications (p < 0.05). We observed an increase or decrease in particular biochemical parameters for the borax group in every application and we established that borax had protective effect against copper toxicity by decreasing and/or increasing the relevant biochemical parameters in brain tissue of fish. The biochemical results of borax and its combinations corresponded to the observations of gene expression data, which similarly concluded that HSP70 and CYP1A genes were strongly induced by copper (p < 0.05). In addition, the expression levels of the sod, cat, and gpx genes in the fish brains exposed to borax and the borax combination groups were significantly higher than the only copper-treated groups. In conclusion, borax supplementation provided significant protection against copper-induced neurotoxicity in trout.