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Water Research Jul 2021Nitrite (NO)-sensitized photolysis plays an important role in the attenuation of effluent-derived trace organic contaminants (e.g., anilines, phenolic compounds, etc.)...
Nitrite (NO)-sensitized photolysis plays an important role in the attenuation of effluent-derived trace organic contaminants (e.g., anilines, phenolic compounds, etc.) in surface waters. However, the kinetics, mechanisms, and influencing factors of photolysis of many emerging contaminants sensitized by NO still remain largely unknown. Herein, we report that NO-sensitized photolysis of the antimicrobial agents parachlormetaxylenol (PCMX) and chlorophene (CP) in aqueous solution under ultraviolet 365 nm (UV) radiation. A nonlinear increase in photolysis rate constants of PCMX and CP was observed with increasing NO concentration. Radical quenching studies and kinetic modeling revealed that hydroxyl radical (HO•) and nitrogen dioxide radicals (NO) contributed dominantly to the removal of PCMX and CP. Solid phase extraction (SPE) combined with high resolution-mass spectrometry (HR-MS) analysis identified a series of intermediate products including hydroxylated, nitrated, nitrosated, and dimerized derivatives. Experiments with isotopically labelled nitrite (NO) showed that the nitro- and nitroso-substituents of intermediate products were derived from the nitrite nitrogen. Based on the identified products and theoretical computations, the mechanisms and pathways of NO-sensitized photolysis of PCMX and CP are elucidated. Deoxygenation partially inhibited the formation of 4-chloro-3,5-dimethyl-2-nitrophenol (nitro-PCMX) while the presence of HO• scavenger such as isopropanol (i-PrOH) suppressed the further transformation of nitro-PCMX. The presence of Mississippi River natural organic matter (MRNOM) inhibited the removal of PCMX and CP, likely due to light screening and radical quenching. However, appreciable degradation of PCMX and CP was still observed in wastewater and wetland water matrices. Results of this study shed some light on the transformation and fate of PCMX and CP in NO-rich wastewater effluents or effluent-impacted surface waters under solar radiation.
Topics: Anti-Infective Agents; Dichlorophen; Mississippi; Nitrites; Photolysis; Water; Water Pollutants, Chemical
PubMed: 34087514
DOI: 10.1016/j.watres.2021.117275 -
Biosensors & Bioelectronics Jul 2024The metal-organic frameworks (MOFs) nanozyme-mediated paper-based analytical devices (PADs) have shown great potential in portable visual determination of phenolic...
The metal-organic frameworks (MOFs) nanozyme-mediated paper-based analytical devices (PADs) have shown great potential in portable visual determination of phenolic compounds in the environment. However, most MOF nanozymes suffer from poor dispersibility and block-like structure, which often prompts deposition and results in diminished enzymatic activity, severely hindering their environmental applications. Here, we proposed colorimetric PADs for the visual detection of dichlorophen (Dcp) based on its significant inhibitory effect on the two-dimensional (2D) MOF nanozyme activity. Specifically, we synthesized a 2D Cu TCPP (Fe) (defined as 2D-CTF) MOF nanozyme exhibiting excellent dispersibility and remarkable peroxidase-like (POD-like) activity, which could catalyze the oxidation and subsequent color change of 3,3',5,5'-tetramethylbenzidine even under neutral conditions. Notably, the POD-like activity of 2D-CTF demonstrated a unique response to Dcp because of the occupation of Fe-N active sites on the 2D-CTF. This property enables the use of 2D-CTF as a highly efficient catalyst to develop colorimetric PADs for naked-eye and portable detection of Dcp. We believe that the proposed colorimetric PADs offer an efficient method for Dcp assay and open fresh avenues for the advancement of colorimetric sensors for analyzing of phenolic toxic substances in real samples.
Topics: Metal-Organic Frameworks; Dichlorophen; Biosensing Techniques; Peroxidases; Peroxidase; Colorimetry; Phenols; Hydrogen Peroxide
PubMed: 38583355
DOI: 10.1016/j.bios.2024.116271 -
Water Research Jul 2018This paper evaluates the oxidation of an antibacterial agent, chlorophene (4-chloro-2-(phenylmethyl)phenol, CP), by permanganate (Mn(VII)) in water. Second-order rate...
This paper evaluates the oxidation of an antibacterial agent, chlorophene (4-chloro-2-(phenylmethyl)phenol, CP), by permanganate (Mn(VII)) in water. Second-order rate constant (k) for the reaction between Mn(VII) and CP was measured as (2.05 ± 0.05) × 10 M s at pH 7.0 for an initial CP concentration of 20.0 μM and Mn(VII) concentration of 60.0 μM. The value of k decreased with increasing pH in the pH range of 5.0-7.0, and then increased with an increase in solution pH from 7.0 to 10.0. The presence of MnO and Fe in water generally enhanced the removal of CP, while the effect of humic acid was not obvious. Fourteen oxidation products of CP were identified by an electrospray time-of-flight mass spectrometer, and direct oxidation, ring-opening, and decarboxylation were mainly observed in the reaction process. The initial reaction sites of CP by Mn(VII) oxidation were rationalized by density functional theory calculations. Toxicity changes of the reaction solutions were assessed by the luminescent bacteria P. phosphoreum, and the intermediate products posed a relatively low ecological risk during the degradation process. The efficient removal of CP in secondary clarifier effluent and river water demonstrated the potential application of this Mn(VII) oxidation method in water treatment.
Topics: Anti-Bacterial Agents; Dichlorophen; Kinetics; Manganese Compounds; Mass Spectrometry; Oxidation-Reduction; Oxides; Photobacterium; Rivers; Water Pollutants, Chemical; Water Purification
PubMed: 29614457
DOI: 10.1016/j.watres.2018.03.057 -
Environmental Health Perspectives Oct 2020Endocrine-disrupting chemicals can interfere with hormonal homeostasis and have adverse effects for both humans and the environment. Their identification is increasingly...
BACKGROUND
Endocrine-disrupting chemicals can interfere with hormonal homeostasis and have adverse effects for both humans and the environment. Their identification is increasingly difficult due to lack of adequate toxicological tests. This difficulty is particularly problematic for cosmetic ingredients, because testing is now banned completely in the European Union.
OBJECTIVES
The aim was to identify candidate preservatives as endocrine disruptors by methods and to confirm endocrine receptors' activities through nuclear receptors .
METHODS
We screened preservatives listed in Annex V in the European Union Regulation on cosmetic products to predict their binding to nuclear receptors using the Endocrine Disruptome and VirtualToxLab™ version 5.8 tools. Five candidate preservatives were further evaluated for androgen receptor (AR), estrogen receptor (), glucocorticoid receptor (GR), and thyroid receptor (TR) agonist and antagonist activities in cell-based luciferase reporter assays in AR-EcoScreen, , MDA-kb2, and GH3.TRE-Luc cell lines. Additionally, assays to test for false positives were used (nonspecific luciferase gene induction and luciferase inhibition).
RESULTS
Triclocarban had agonist activity on AR and at and antagonist activity on GR at and TR at . Triclosan showed antagonist effects on AR, , GR at and TR at , and bromochlorophene at (AR and TR) and at ( and GR). AR antagonist activity of chlorophene was observed [inhibitory concentration at 50% (IC) ], as for its substantial agonist at and TR antagonist activity at . Climbazole showed AR antagonist (), agonist at , and TR antagonist activity at .
DISCUSSION
These data support the concerns of regulatory authorities about the endocrine-disrupting potential of preservatives. These data also define the need to further determine their effects on the endocrine system and the need to reassess the risks they pose to human health and the environment. https://doi.org/10.1289/EHP6596.
Topics: Androgen Receptor Antagonists; Carbanilides; Cell Line; Computer Simulation; Dichlorophen; Endocrine Disruptors; Genes, Reporter; Humans; Imidazoles; Receptors, Androgen; Receptors, Estrogen; Receptors, Glucocorticoid; Triclosan
PubMed: 33064576
DOI: 10.1289/EHP6596 -
Parasitology Nov 2019Alveolar echinococcosis is a neglected parasitic zoonosis caused by the metacestode Echinococcus multilocularis, which grows as a malignant tumour-like infection in the...
Alveolar echinococcosis is a neglected parasitic zoonosis caused by the metacestode Echinococcus multilocularis, which grows as a malignant tumour-like infection in the liver of humans. Albendazole (ABZ) is the antiparasitic drug of choice for the treatment of the disease. However, its effectiveness is low, due to its poor absorption from the gastro-intestinal tract. It is also parasitostatic and in some cases produces side-effects. Therefore, an alternative to the treatment of this severe human disease is necessary. In this context, the repositioning of drugs combined with nanotechnology to improve the bioavailability of drugs emerges as a useful, fast and inexpensive tool for the treatment of neglected diseases. The in vitro and in vivo efficacy of dichlorophen (DCP), an antiparasitic agent for intestinal parasites, and silica nanoparticles modified with DCP (NP-DCP) was evaluated against E. multilocularis larval stage. Both formulations showed a time and dose-dependent in vitro effect against protoscoleces. The NP-DCP had a greater in vitro efficacy than the drug alone or ABZ. In vivo studies demonstrated that the NP-DCP (4 mg kg-1) had similar efficacy to ABZ (25 mg kg-1) and greater activity than the free DCP. Therefore, the repurposing of DCP combined with silica nanoparticles could be an alternative for the treatment of echinococcosis.
Topics: Animals; Antiparasitic Agents; Dichlorophen; Drug Repositioning; Drug Therapy, Combination; Echinococcosis; Echinococcus multilocularis; Female; Life Cycle Stages; Mice; Nanoparticles; Nanotechnology; Silicon Dioxide
PubMed: 31397256
DOI: 10.1017/S0031182019001057 -
Chemosphere Dec 2022Cytotoxicity of non-polar narcotic chemicals can be predicted by quantitative structure activity relationship (QSAR) models, but the polar narcotic chemicals' actual...
Cytotoxicity of non-polar narcotic chemicals can be predicted by quantitative structure activity relationship (QSAR) models, but the polar narcotic chemicals' actual cytotoxicity exceeds the predicted values by their chemical structures. This discrepancy indicates that the molecular mechanism by which polar narcotic chemicals exert their toxicity is unclear. Taking advantage of Saccharomyces cerevisiae (yeast) functional genome-wide heterozygous essential gene knockout mutants, we here have identified the specific molecular fingerprints of two main chemical structure groups (phenols and anilines) of polar narcotic chemicals (dichlorophen (DCP), 4-chlorophenol (4-CP), 2, 4, 6-trichlorophenol (TCP), 3, 4-dichloroaniline (DCA) and N-methylaniline (NMA)) and one non-polar narcotic chemical 2, 2, 2-trichloroethanol (TCE). Especially, we identify 33, 57, 54, 46, 59 and 53 responsive strains through exposure to TCE, DCP, 4-CP, TCP, DCA and NMA with three test concentrations, respectively, revealing that these polar narcotic chemicals have more responsive strains than the non-polar narcotic chemical. Remarkably, we find that the molecular fingerprints of polar narcotic chemicals in different chemical structure groups are obviously varied, particularly phenols and anilines have their own specific molecular fingerprints. Interestingly, our results demonstrate that the molecular toxicity mechanisms of anilines are associated with DNA replication, but phenols are related with pathway of RNA degradation. Additionally, we find that the two knockout strains (SME1 and DIS3) and the three knockout strains (TSC11, RSP5 and HSF1) can specifically respond to exposure to phenols and anilines, respectively. Thus, they may be served as potential biomarkers to distinguish phenols from anilines. Collectively, our works demonstrate that the functional genomic platform of yeast essential gene mutants can not only act as an effective tool to identify key specific molecular fingerprints for polar narcotic chemicals, but also help to understand the molecular mechanisms of polar narcotic chemicals.
Topics: Aniline Compounds; Dichlorophen; Genes, Essential; Narcotics; Phenols; Ribonucleoproteins, Small Nuclear; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 36087727
DOI: 10.1016/j.chemosphere.2022.136343 -
Biosensors Feb 2021Chlorophene is an important antimicrobial agent present in disinfectant products which has been related to health and environmental effects, and its detection has been...
Chlorophene is an important antimicrobial agent present in disinfectant products which has been related to health and environmental effects, and its detection has been limited to chromatographic techniques. Thus, there is a lack of research that attempts to develop new analytical tools, such as biosensors, that address the detection of this emerging pollutant. Therefore, a new biosensor for the direct detection of chlorophene in real water is presented, based on surface plasmon resonance (SPR) and using a laccase enzyme as a recognition element. The biosensor chip was obtained by covalent immobilization of the laccase on a gold-coated surface through carbodiimide esters. The analytical parameters accomplished resulted in a limit of detection and quantification of 0.33 mg/L and 1.10 mg/L, respectively, fulfilling the concentrations that have already been detected in environmental samples. During the natural river's measurements, no significant matrix effects were observed, obtaining a recovery percentage of 109.21% ± 7.08, which suggested that the method was suitable for the fast and straightforward analysis of this contaminant. Finally, the SPR measurements were validated with an HPLC method, which demonstrated no significant difference in terms of precision and accuracy, leading to the conclusion that the biosensor reflects its potential as an alternative analytical tool for the monitoring of chlorophene in aquatic environments.
Topics: Anti-Infective Agents; Biosensing Techniques; Carbodiimides; Dichlorophen; Gold; Limit of Detection; Surface Plasmon Resonance
PubMed: 33572259
DOI: 10.3390/bios11020043 -
International Journal of Biological... Dec 2017Pesticide intoxication is a major public health concern, and unfortunately there is not an effective treatment for severe organophosphorus pesticide intoxication. In...
Pesticide intoxication is a major public health concern, and unfortunately there is not an effective treatment for severe organophosphorus pesticide intoxication. In this work, a non-immunogenic enzymatic bioconjugate based on cytochrome P450 was assayed for organophosphorus pesticide transformation. Enzyme therapy is an alternative approach to inactivate pesticides in the bloodstream, transforming them into less toxic metabolites. A variant of cytochrome P450 (CYP F87A) from Bacillus megaterium was chemically modified with polyethylene glycol. The PEGylated enzyme showed enhanced pesticide transformation activity when compared with the unmodified protein. The transformation rates were higher than those obtained with the unmodified enzyme for all six pesticides transformed. The specific activity of PEGylated preparation for parathion and dichlorophen was up to 9-times higher than these obtained with the unmodified enzyme. In addition, the modified CYP (CYP-PEG) remained active at extremely high pHs, maintaining 90% of its maximal activity at pH 11, as opposed to the unmodified CYP that retained less than 20% of its maximal activity at that pH. In addition, the bioconjugate showed good catalytic activity in blood serum and innocuousness on immune cells. The potential use of PEGylated CYP as a detoxification strategy for pesticide poisoning is demonstrated and discussed.
Topics: Animals; Bacillus megaterium; Biocatalysis; Biotransformation; Cytochrome P-450 Enzyme System; Hydrogen-Ion Concentration; Kinetics; Macrophages; Mice; Models, Molecular; Oxidation-Reduction; Pesticides; Polyethylene Glycols; Protein Conformation; RAW 264.7 Cells; Substrate Specificity; Temperature
PubMed: 28690168
DOI: 10.1016/j.ijbiomac.2017.07.014 -
Brazilian Journal of Microbiology :... Dec 2020With the high-frequency use or abuse of antifungal drugs, the crisis of drug-resistant fungi continues to increase worldwide; in particular, the infection of...
With the high-frequency use or abuse of antifungal drugs, the crisis of drug-resistant fungi continues to increase worldwide; in particular, the infection of drug-resistant Candida albicans brings the great challenge to the clinical treatment. Therefore, to decelerate the spread of this resistance, it is extremely urgent to facilitate the new antifungal targets with novel drugs. Phosphopantetheinyl transferases PPTases (Ppt2 in Candida albicans) had been identified in bacterium and fungi and mammals, effects as a vital enzyme in the metabolism of organisms in C. albicans. Ppt2 transfers the phosphopantetheinyl group of coenzyme A to the acyl carrier protein Acp1 in mitochondria for the synthesis of lipoic acid that is essential for fungal respiration, so making Ppt2 an ideal target for antifungal drugs. In this study, 110 FDA-approved drugs were utilized to investigate the Ppt2 inhibition against drug-resistant Candida albicans by the improved fluorescence polarization experiments, which have enough druggability and structural variety under the novel strategy of drug repurposing. Thereinto, eight agents revealed the favourable Ppt2 inhibitory activities. Further, broth microdilution assay of incubating C. albicans with these eight drugs showed that pterostilbene, procyanidine, dichlorophen and tea polyphenol had the superior MIC values. In summary, these findings provide more valuable insight into the treatment of drug-resistant C. albicans.
Topics: Antifungal Agents; Candida albicans; Drug Repositioning; Drug Resistance, Fungal; Enzyme Inhibitors; Fungal Proteins; Microbial Sensitivity Tests; Transferases (Other Substituted Phosphate Groups)
PubMed: 32557281
DOI: 10.1007/s42770-020-00318-w -
Water Research Apr 2021Mineral-humic complexes, known as mineral-associated organic matter (MAOM), are ubiquitous in natural waters. However, the interaction between organic pollutants and...
Mineral-humic complexes, known as mineral-associated organic matter (MAOM), are ubiquitous in natural waters. However, the interaction between organic pollutants and MAOM remains elusive, which may affect their degradation process. In this study, photochemical transformation of chlorophene (CP) in the presence of MAOM, prepared by coating aluminum hydroxide with humic acid (HA-HAO), was investigated. Our results showed that the degradation of CP was significantly enhanced in the presence of HA-HAO, and the degradation rate constant was ~5 times as that with HA only. It was because the adsorption of CP to HA-HAO particles was greatly enhanced, and concentration of reactive oxygen species (ROS) was increased on HA-HAO surfaces, which further promoted the reactions between CP and ROS. The quenching experiments combined with EPR technology confirmed that superoxide anion (O) was the primary reactive radical on CP photodegradation. More importantly, the degradation of CP with HA-HAO followed a hydroxylation process, rather than the oligomerization reaction with HA only. Spectroscopic analysis provided direct evidence for the formation of hydrogen bonding between CP phenolic hydroxyl group and surface oxygen of HAO, which would suppress the reactivity of phenolic hydroxyl group, consequently the ortho- and meta-positions of CP became more facile for the hydroxylation reaction. This study shows the importance of MAOM in altering the photochemical behavior and transformation pathway of organic contaminants.
Topics: Aluminum Hydroxide; Dichlorophen; Humic Substances; Photolysis; Water Pollutants, Chemical
PubMed: 33582491
DOI: 10.1016/j.watres.2021.116904