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Dichlorvos (DDVP) has been used in the management of agricultural pests for a long time. DDVP can cause DNA damage in mammals, and its residues in the environment and food have attracted attention. In this study, we reported a DDVP-degrading strain, Stenotrophomonas acidaminiphila G1, which could degrade DDVP to 20 mg/L with a DT50 of 3.81 min at 37 °C, a pH of 7.0, and a concentration of 1.18 × 1010 colony-forming units (CFUs)/mL. Strain G1’s DDVP degradation products were determined by comparison with standard substances and UPLC-MS/MS analysis. The results showed that dimethyl phosphate (DMPP) was the main metabolite of DDVP, and its toxicity to non-target organisms was significantly lower than that of the parent compound. Furthermore, the key genes for the degradation of DDVP by strain G1 were analyzed using whole-genome sequencing. A methyl parathion hydrolase gene, mpd, was identified, and its activity was verified through prokaryotic expression and enzyme kinetics. The purified enzyme MPD could entirely degrade 20 mg/L DDVP within 1 min. These results not only provide biological resources for the rapid degradation of organophosphorus pesticides but also offer a theoretical basis for the efficient remediation of pesticide residues.

The adsorption mechanism of dichlorvos onto coconut fibre biochar (CFB) was investigated by the batch adsorption technique. Coconut fibre waste material was synthesised at 600 °C for 4 h under oxygen-limited conditions. The biochar was modified by HCl acid to enhance the specific surface area and porosity. The characteristics of the biochar were analysed by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) specific surface area, and Fourier transform-infrared (FT-IR). The results showed that the BET specific surface area of biochar was 402.4 m2/g. Experimental data presented a good fit to Langmuir isotherm and the pseudo-second-order model. Langmuir isotherm illustrated that monolayer adsorption of dichlorvos occurred on the surface of CFB, with a maximum adsorption capacity of 90.9 mg/g. The diffusion model confirmed that the liquid film diffusion was the rate-limiting step, and the major diffusion mechanism of dichlorvos onto biochar. The BET result after dichlorvos adsorption demonstrated that pore-filling occurred and occupied 58.27%. The pore-filling and chemical interactions, performed important roles in the adsorption of dichlorvos onto CFB. Chemical adsorption is comprised of two interactions, which are hydrophobic and H-bonding, but the prime is H-bonding. CFB is a very potential material for the removal of dichlorvos and environmental pollutants.

Bacteria inhabiting the gut of insects provide many benefits to their hosts, such as aiding in food digestion, reproduction, and immunity, tissue homeostasis, adaptation to environment and resistance to pathogen and pesticides. The cowpea beetle, Callosobruchus maculatus , is a serious cosmopolitan pest of pulses. This beetle has lent itself as a guinea pig for several ecological studies. It harbors a consortium of bacterial communities in its gut, but the evidence for their role in its physiology is fragmentary. In this work, we hypothesized that gut microbiota mediates C . maculatus resistance to dichlorvos (DDVP or O , O -dimethyl O -2,2-dichlorovinylphosphate) and represent the target of Lippia adoensis (Gambian Tea Bush) essential oil (EO). Symbiotic and aposymbiotic beetles were exposed to artificial cowpea seeds earlier treated with DDVP or EO. Adult mortality and changes in gut bacterial community composition and abundance were examined at F 1 and F 5 generations. The susceptibility of experimental beetles to DDVP was significantly affected by their symbiotic status. The adult mortality decreased across generations in DDVP treatments, and remained significantly higher in aposymbiotic groups. In EO treatments, the mortality was consistent irrespective of symbiotic status and experimental generations. When compared to DDVP and the Control, EO treatments had significantly lower bacterial richness and diversity, as well as lower abundance of Proteobacteria, Firmicutes, and Bacteroidetes. These results support our hypothesis and describe the responses of gut microbial communities to pesticide treatments. This could be of interest for developing new management strategies of this pest.

Dichlorvos is an organophosphate pesticide that is commonly used for agricultural and domestic control of pests and insects. Despite its usefulness, it exerts reproductive toxicity and induces male sexual dysfunction. On the other hand, curcumin has been reported to improve sexual dysfunction. However, till date, no study has reported the impact of curcumin on dichlorvos-induced sexual dysfunction. This study investigated the effect and associated mechanism of curcumin on dichlorvos-induced sexual dysfunction. Thirty-two male Wistar rats were randomized into four groups; the control (1 mL of olive oil), curcumin-treated (100 mg/kg), DDVP-treated (98.54 g/m 3 of dichlorvos by inhalation), and DDVP + Curcumin-treated. Dichlorvos induced sexual dysfunction as depicted by reduced motivation to mate (8.38 ± 0.18 vs. 4.00 ± 0.33, P  < 0.0001), prolonged latencies (46.63 ± 1.30 vs. 98.75 ± 1.32, P  < 0.0001) and reduced frequencies of mount (14.88 ± 0.52 vs. 8.63 ± 0.38), intromission (9.38 ± 0.50 vs. 3.75 ± 0.31, P  < 0.0001), and ejaculation (7.63 ± 0.38 vs. 1.50 ± 0.19, P  < 0.0001). These findings were accompanied by suppression of hypothalamic-pituitary–testicular axis, evidenced by marked reductions in circulating FSH (60.00 ± 1.04 vs. 21.13 ± 0.52, P  < 0.0001), LH (46.38 ± 1.38 vs. 19.00 ± 0.46, P  < 0.0001), and testosterone (6.01 ± 0.50 vs. 0.74 ± 0.05, P  < 0.0001). Nonetheless, the administration of curcumin in dichlorvos-exposed rats significantly attenuated dichlorvos-induced sexual dysfunction by improving the assessed indices of male sexual act. Also, curcumin significantly increased serum levels of FSH (21.13 ± 0.52 vs. 47.25 ± 0.10, P  < 0.0001), LH (19.00 ± 0.46 vs. 43.00 ± 1.49), and testosterone (0.74 ± 0.05 vs. 3.98 ± 0.08, P  < 0.0001). This study revealed that curcumin attenuated dichlorvos-induced sexual dysfunction by activating the hypothalamic-pituitary–testicular axis and upregulating circulating testosterone.

Forensic entomology has relied on species-specificity, quantitative and qualitative variations of cuticular hydrocarbons to successfully carry out chemotaxonomic identification of insects based on species, age and gender. This work studied the effects of dichlorvos on the cuticular hydrocarbon profiles of some adult sarco-saprophagous insects of forensic importance that fed on dichlorvos-poisoned carrions for utility during death investigations. Cuticular hydrocarbons (CHCs) were extracted from adult insects of the species Chrysomya albiceps, Sarcophaga exuberans, Musca domestica , Hermetia illucens , Dermestes maculatus and Necrobia rufipes from both dichlorvos-poisoned and control pig ( Sus scrofa Linnaeus) carrions and subjected to chemotaxonomic profiling using Gas Chromatography-Mass Spectrometry (GC–MS). A total of 41 CHCs were successfully identified from insects of both the dichlorvos-poisoned and control carrions ranging from C8 to C33 carbons consisting of majorly the n-alkanes, methyl branched alkanes and an alkene. There was a higher abundance of CHCs present in the insects of dichlorvos-poisoned carrions than the control group. The highest mean peak concentration and abundance of the CHCs was recorded by 2,6,10,14 -Tetramethyl Pentadecane (10.38 ± 0.53 μg/mg for dichlorvos-poisoned carrions and 8.99 ± 1.13 μg/mg for the control carrions). The visualization of the species-specific differences in CHCs compositions showed less overlapping CHCs clusters and quantitative metrics of principal component analysis plots of the insects from both carrion groups with high eigenvalues > 3 which were indications of good species level discrimination. The study showed that insects’ CHCs profiles of dichlorvos-poisoned and control carrions exhibited uniqueness cum variations in terms of abundance and chemical identity.

A biomass nitrogen and sulfur codoped carbon dots (NS-Cdots) was prepared by a simple and clean hydrothermal method using leek, and was employed as efficient fluorescent probes for sensitive detection of organophosphorus pesticides (OPs). The leek-derived NS-Cdots emitted blue fluorescence, but was quenched by H2O2. Due to acetylcholinesterase/choline oxidase–based cascade enzymatic reaction that produces H2O2 and the inhibition effect of OPs on acetylcholinesterase activity, a NS-Cdots-based fluorescence “off-on” method to detect OPs-dichlorvos (DDVP) was developed. More sensitivity and wider linear detection range were achieved from 1.0 × 10−9 to 1.0 × 10−3 M (limit of detection = 5.0 × 10−10 M). This developed method was applied to the detection of DDVP in Chinese cabbage successfully. The average recoveries were in the range of 96.0~104.0% with a relative standard deviation of less than 3.3%. In addition, the NS-Cdots fluorescent probes were also employed successfully in multicolor imaging of living cells, manifesting that the NS-Cdots fluorescent probes have great application potential in agricultural and biomedical fields.

Long-lasting insecticide nets (LLINs), which have insecticide incorporated within the fibers, have been widely used for control of malaria and other insect-vectored diseases. Only recently have researchers begun exploring their use for control of agricultural pests. In this study, we evaluated the toxicity of a deltamethrin-incorporated LLIN, ZeroFly (Vestergaard–Frandsen, Washington, DC) for control of the brown marmorated stink bug, Halyomorpha halys (Stål). In the lab, exposure to the ZeroFly net for 10 s resulted in >90% mortality of H. halys nymphs and >40% mortality of H. halys adults. Longer exposure to the net resulted in higher mortality. In another experiment, a 15-cm2 sheet of ZeroFly net placed inside of the stink bug trap provided long-lasting kill of H. halys adults equal to or better than standard dichlorvos kill strip. Potential for the use of ZeroFly nets for H. halys IPM is discussed.

Dichlorvos (DDVP) is widely applied in the agricultural industry, and its residues are considered hazardous to the environment. Microbial bioremediation is an innovative technology with the potential to mitigate such pollution. Trichoderma atroviride strain T23, a filamentous fungus, is very efficient at degrading DDVP. Therefore, we used DDVP as a model organophosphate pesticide to study the mechanism by which Trichoderma degrades organophosphate pesticides, with the aim of attaining a global understanding of the molecular mechanism of enzymatic degradation of organophosphate pesticides by beneficial fungi. DDVP can be biodegraded via two routes, and the primary one involves hydrolysis of the P-O bond, which can result in the production of the novel degradation intermediate trichloroethanol. TaPon1-like showed continuously high expression during 120 h, and deletion of the gene decreased the efficiency of P-O bond hydrolysis. The enzyme produced by TaPon1-like had a low K m for DDVP (0.23 mM) and a high k cat (204.3 s −1 ). The enzyme was able to hydrolyze broad substrates such as organophosphate oxons and lactone and maintain stable activity in a wide range of pH and temperature values. The TaPon1-like hydrolase played an important role in the first step of DDVP degradation by strain T23 and contributed to a comprehensive understanding of the mechanism of organophosphate pesticide degradation.

In a Policy Forum, Irva Hertz-Picciotto and colleagues review the scientific evidence linking organophosphate pesticides to cognitive, behavioral, and neurological deficits in children and recommend actions to reduce exposures.

The objective of current study was to evaluate the neuroprotective effects of bacoside A and bromelain against dichlorvos induced toxicity. The healthy, 6–8 weeks old male Swiss mice were administered in separate groups subacute doses of dichlorvos (40 mg/kg bw), bacoside A (5 mg/kg bw) and bromelain (70 mg/kg bw). In order to determination of oxidative stress in different groups, thiobarbituric acid reactive substances (TBARS) and protein carbonyl content (PCC) were studied in the present investigation. Moreover, for toxic manifestation at molecular level the site-specific gene amplification of acetylcholinesterase (AChE) gene was studied in the brain. Nonetheless, the protective effects of bacoside A and bromelain were also evaluated on the TBARS, PCC and AChE gene. The exposure of dichlorvos leads to significant increase in TBARS level (p < 0.01, p < 0.001) and PCC. Besides, the decline in DNA yield, expression of amplified products of AChE gene was observed in the brain of dichlorvos treated group. The bacoside A and bromelain treatments significantly decreased the level of TBARS (p < 0.05, (p < 0.01) and PCC whereas, increase in the DNA yield and expression of amplified AChE gene products were observed in the brain compared to only dichlorvos treated mice. The overall picture which emerged after critical evaluation of results indicated that the dichlorvos induced oxidative stress and alteration in AChE gene expression showed significant improvement owing to the treatments of bacoside A and bromelain. Thus, bacoside A and bromelain are very effective in alleviating neurotoxicity induced by dichlorvos.