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In this work, the interaction between different chloro-substituted phenylurea herbicides (diuron (DIU) and chlortoluron (CHL)) and BSA were investigated and compared at three different temperatures (283 K, 298 K and 310 K) adopting UV-vis, fluorescence, and circular dichroism spectra. The quenching mechanism of the interaction was also proposed. The energy transfer between BSA and DIU/CHL was investigated. The binding sites of DIU/CHL and BSA and the variations in the microenvironment of amino acid residues were studied. The changes of the secondary structure of BSA were analyzed. The results indicate that both DIU and CHL can significantly interact with BSA, and the degree of the interaction between DIU/CHL and BSA increases with the increase of the DIU/CHL concentration. The fluorescence quenching of BSA by DIU/CHL results from the combination of static and dynamic quenching. The DIU/CHL has a weak to moderate binding affinity for BSA, and the binding stoichiometry is 1:1. Their binding processes are spontaneous, and hydrophobic interaction, hydrogen bonds and van der Waals forces are the main interaction forces. DIU/CHL has higher affinity for subdomain IIA (Site I) of BSA than subdomain IIIA (Site II), and also interacts with tryptophan more than tyrosine residues. The energy transfer can occur from BSA to DIU/CHL. By comparison, the strength of the interaction of DIU-BSA is always greater than that of CHL-BSA, and DIU can destroy the secondary structure of BSA molecules greater than CHL and thus the potential toxicity of DIU is higher due to DIU with more chlorine substituents than CHL. It is expected that this study on the interaction can offer in-depth insights into the toxicity of phenylurea herbicides, as well as their impact on human and animal health at the molecular level., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The present study evaluated the performance of the fungus Trichoderma reesei to tolerate and biodegrade the herbicide diuron in its agrochemical presentation in agar plates, liquid culture, and solid-state fermentation. The tolerance of T. reesei to diuron was characterized through a non-competitive inhibition model of the fungal radial growth on the PDA agar plate and growth in liquid culture with glucose and ammonium nitrate, showing a higher tolerance to diuron on the PDA agar plate (inhibition constant 98.63 mg L -1 ) than in liquid culture (inhibition constant 39.4 mg L -1 ). Diuron biodegradation by T. reesei was characterized through model inhibition by the substrate on agar plate and liquid culture. In liquid culture, the fungus biotransformed diuron into 3,4-dichloroaniline using the amide group from the diuron structure as a carbon and nitrogen source, yielding 0.154 mg of biomass per mg of diuron. A mixture of barley straw and agrolite was used as the support and substrate for solid-state fermentation. The diuron removal percentage in solid-state fermentation was fitted by non-multiple linear regression to a parabolic surface response model and reached the higher removal (97.26%) with a specific aeration rate of 1.0 vkgm and inoculum of 2.6 × 10 8 spores g -1 . The diuron removal in solid-state fermentation by sorption on barley straw and agrolite was discarded compared to the removal magnitude of the biosorption and biodegradation mechanisms of Trichoderma reesei. The findings in this work about the tolerance and capability of Trichoderma reesei to remove diuron in liquid and solid culture media demonstrate the potential of the fungus to be implemented in bioremediation technologies of herbicide-polluted sites., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

In this study, Haematococcus pluvialis and Coelastrella saipanensis were evaluated for heterotrophic nutrition potential in dairy waste medium by blocking the PSII using DCMU. The study was done by four sets of experiments. In the first set, in the different concentrations DCMU-treatments, 20μL showed pronounced effect in H. pluvialis and C. saipanensis as 89 % and 83% decrease in cells (>30 and > 250 cells/mL) compared to control (536 ± 12.35 × 10 4 and 1167 ± 15.35 × 10 4  cells/mL, respectively). Damage to the PS II by DCMU interrupted the growth, which in turn produced a significant drop in the number of cells. In the second round of experiment, growth of algae in various dairy waste concentrations suggest that dairy wastewater (DWW) provides enough nutrients to produce 35.71 % and 64.74 % more cells in H. pluvialis and C. saipanensis, respectively compared to the control. In the third set, high DCMU concentration was added to microalgae cultures in DWW to assess the heterotrophic nutrition potential. Growth in cell number 34.4 ± 19 and 617.46 ± 60.44 cells/mL was recorded in H. pluvialis and C. saipanensis when grown control medium whereas addition of DCMU reduced the cell number to 1.53 ± 0.75 and 55.13 ± 0.75 cells/mL on 15 th day, respectively. This shows cells in cultures treated with DCMU reveal that algae can sustain their metabolic activity by utilizing the nutrients of dairy waste inhibiting photosystem. Fourth round of experiments found that microalgae could resume their growth and productivity by adapting to heterotrophic nutritional behaviour when DCMU given in mild dose at different time interval. This study conclude as C. saipanensis grows more readily by absorbing dairy waste nutrients than H. pluvialis. Therefore, C. saipanensis is an excellent choice for wastewater treatment through sustainable environmentally benign process after scale-up investigation. These results provide useful information to advance to molecular study for measuring microalgae's capability for bioremediation application., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Kulanthaiyesu Arunkumar reports financial support was provided by Central University of Kerala. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Diuron is a globally used herbicide for weed control but has anti-androgenic effects on androgens (testosterone and androstenedione), antagonist effects on thyroid hormone signaling, and haematological effects due to their biotransformation in fish. Endocrine-disrupting biomarkers such as thyroid hormones, sex hormones, and haematological indices of Clarias gariepinus sub-adults exposed to sub-lethal diuron concentrations were studied over a 28-day period. C. gariepinus (n = 200) sub-adults were exposed to sub-lethal concentrations (0.00, 0.09, 0.18, 0.26, and 0.35 mg/L) of diuron. Changes in the hormonal and haematological profiles of the exposed fish were concentration and exposure duration-dependent. The thyroxine (T4), tri-iodothyronine (T3), and 17β-estradiol (E2) profiles decreased with an increase in concentration and exposure duration. The haemoglobin, pack cell volume, red blood cell, white blood cell, mean cell volume, and mean corpuscular haemoglobin cell decreased, while the mean corpuscular haemoglobin increased with an increase in concentration and exposure duration. Diuron induced stress and altered the physiological mechanisms of fish, and its application in farmlands should be regulated so as to enable a sustainable aquatic eco-system and fishery resources., Competing Interests: Declaration of competing interest The authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

In the environment, or during mammalian metabolism, the diuron herbicide (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is transformed mainly into 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and 3,4-dichloroaniline (DCA). Previous research suggests that such substances are toxic to the urothelium of Wistar rats where, under specific exposure conditions, they may induce urothelial cell degeneration, necrosis, hyperplasia, and eventually tumors. However, the intimate mechanisms of action associated with such chemical toxicity are not fully understood. In this context, the purpose of the current in vitro study was to analyze the underlying mechanisms involved in the urothelial toxicity of those chemicals, addressing cell death and the possible role of mitochondrial dysfunction. Thus, human 1T1 urothelial cells were exposed to six different concentrations of diuron, DCA, and DCPMU, ranging from 0.5 to 500 µM. The results showed that tested chemicals induced oxidative stress and mitochondrial damage, cell cycle instability, and cell death, which were more expressive at the higher concentrations of the metabolites. These data corroborate previous studies from this laboratory and, collectively, suggest mitochondrial dysfunction as an initiating event triggering urothelial cell degeneration and death.

Diuron is a phenylurea herbicide widely used in the agricultural industry. In recent years, the risk of infertility and developmental defects has increased due to exposure to environmental pollutants. In this study, we investigated the toxicity of diuron in fetal mouse testes using three-dimensional organ cultures. Fetal testes derived from embryonic day (E) 14.5 were cultured with 200 µM diuron for 5 days. The results revealed that diuron did not impair fetal germ cell proliferation or the expression levels of germ cell markers such as Ddx4, Dazl, Oct 4, Nanog, Plzf, and TRA 98. Similarly, the gene or protein expression of the Sertoli cell markers Sox9 and Wt1 in diuron-exposed fetal testes did not change after 5 days of culture. In contrast, diuron increased fetal Leydig cell markers (FLC), Cyp11a1, Cyp17a1, Thbs2, and Pdgf α, and decreased adult Leydig cell (ALC) markers, Sult1e1, Hsd173, Ptgds, and Vcam1. However, 3-βHSD, an FLC and ALC marker, was consistently maintained upon exposure to diuron in fetal testes compared to non-treated groups. In conclusion, our study demonstrates that diuron negatively impacts Fetal Leydig cell development, although it does not affect germ and Sertoli cells., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Hyun Jung Park reports equipment, drugs, or supplies was provided by Sangji University. Hyun Jung Park reports a relationship with Sangji University that includes: non-financial support., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Modern agricultural cultivation relies heavily on genetically modified plants that survive after exposure to herbicides that kill weeds. Despite this biotechnology, there is a growing need for new sustainable, environmentally friendly, and biodegradable herbicides. We developed a novel [CuL 2 ]Br 2 complex (L = bis{4H-1,3,5-triazino[2,1-b]benzothiazole-2-amine,4-(2-imidazole) that is active on PSII by inhibiting photosynthetic oxygen evolution on the micromolar level. [CuL 2 ]Br 2 reduces the F V of PSII fluorescence. Artificial electron donors do not rescind the effect of [CuL 2 ]Br 2 . The inhibitory mechanism of [CuL 2 ]Br 2 remains unclear. To explore this mechanism, we investigated the effect of [CuL 2 ]Br 2 in the presence/absence of the well-studied inhibitor DCMU on PSII-containing membranes by OJIP Chl fluorescence transient measurements. [CuL 2 ]Br 2 has two effects on Chl fluorescence transients: (1) a substantial decrease of the Chl fluorescence intensity throughout the entire kinetics, and (2) an auxiliary "diuron-like" effect. The initial decrease dominates and is observed both with and without DCMU. In contrast, the "diuron-like" effect is small and is observed only without DCMU. We propose that [CuL 2 ]Br 2 has two binding sites for PSII with different affinities. At the high-affinity site, [CuL 2 ]Br 2 produces effects similar to PSII reaction center inhibition, while at the low-affinity site, [CuL 2 ]Br 2 produces effects identical to those of DCMU. These results are compared with other PSII-specific classes of herbicides.

The toxicity of diuron herbicide and its metabolites has been extensively investigated; however, their precise toxic mechanisms have yet to be fully appreciated. In this context, we evaluated the toxic mechanism of diuron, 3,4-dichloroaniline (DCA) and 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU), using Caenorhabditis elegans (C. elegans) in the L1 larval stage. For this purpose, worms were acutely exposed to the test chemicals with a preliminary concentration range of 0.5 to 500 μM and first analyzed for lethality (%). Next, the highest concentration (500 μM) was considered for survival (%), reactive oxygen and nitrogen species (RONS), glutathione (GSH) and ATP levels, autophagy index, behavior, and dopaminergic neurodegeneration parameters. Interestingly, increased lethality (%) was found for all chemicals at the higher concentrations tested (100 and 500 μM), with significant differences at 500 μM DCA (p < 0.05). A decrease in the median survival was observed mainly for DCA. Although no changes were observed in RONS production, GSH levels were significantly increased upon diuron and DCA treatment, likely reflecting an attempt to restore the redox status. Moreover, diuron and its metabolites impaired ATP levels, suggesting an alteration in mitochondrial function. The latter may trigger autophagy as an adaptive survival mechanism, but this was not observed in C. elegans. Dopaminergic neurotoxicity was observed upon treatment with all the tested chemicals, but only diuron induced alterations in the worms' locomotor behavior. Combined, these results indicate that exposure to high concentrations of diuron and its metabolites elicit distinct adverse outcomes in C. elegans, and DCA in particular, plays an important role in the overall toxicity observed in this experimental model., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Diuron [DU; 3-(3,4-dichlorophenyl)-1,1-dimethylurea], a widely used herbicide for weed control, arouses ecological and health risks due to its environment persistence. Our findings revealed that DU at 0.125-2.0 mg L -1 caused oxidative damage to rice. RNA-sequencing profiles disclosed a globally genetic expression landscape of rice under DU treatment. DU mediated downregulated gene encoding photosynthesis and biosynthesis of protein, fatty acid, and carbohydrate. Conversely, it induced the upregulation of numerous genes involved in xenobiotic metabolism, detoxification, and anti-oxidation. Furthermore, 15 DU metabolites produced by metabolic genes were identified, 7 of which include two Phase I-based and 5 Phase II-based derivatives, were reported for the first time. The changes of resistance-related phytohormones, like JA, ABA, and SA, in terms of their contents and molecular-regulated signaling pathways positively responded to DU stress. Our work provides a molecular-scale perspective on the response of rice to DU toxicity and clarifies the biotransformation and degradation fate of DU in rice crops.

Diuron, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, is a worldwide used herbicide whose biotransformation gives rise to the metabolites, 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and 3,4-dichloroaniline (DCA). Previous studies indicate that diuron and/or its metabolites are toxic to the bladder urothelium of the Wistar rats where, under certain conditions of exposure, they may induce successively urothelial cell degeneration, necrosis, hyperplasia and eventually tumors. The hypothesis was raised that the molecular initiating event (MIE) of this Adverse Outcome Pathway is the mitochondrial toxicity of those compounds. Therefore, this study aimed to investigate in vitro the metabolic alterations resulting from urothelial mitochondria isolated from male Wistar rats exposure to diuron, DCPMU and DCA at 10 and 100 µM. A non-targeted metabolomic analysis using mass spectrometry showed discriminative clustering among groups and alterations in the intensity abundance of membrane-associated molecules phosphatidylcholine, phosphatidylinositol and phosphatidylserine, in addition to methylhexanoyl-CoA and, particularly for diuron 100 µM, dehydro-L-gulonate, all of them involved in critical mitochondrial metabolism. Collectively, these data indicate the mitochondrial dysfunction as an MIE that triggers cellular damage and death observed in previous studies.

Diuron, a widely used phenylurea herbicide, has been frequently detected in marine organism and seawater all over the world. But the understanding of potential damage of diuron on reproduction in marine fish is currently not enough. Herein, marine medaka (Oryzias melastigma) were continuously exposed to 0, 5, 50, 500, and 5000 ng/L diuron from embryo (0 dpf) to adult (180 dpf) stage. The results suggested that diuron had an adverse influence on male reproduction for marine medaka, including decreased gonado somatic index, histological changes of testes, decreased mobility of sperm, and reduced fecundity through disrupting the balance of sex hormone and genes expression related to hypothalamus-pituitary-gonadal-liver (HPGL) axis. The reduced fecundity was reflected in abnormal sexual behaviors, further inhibited growth and development of F1 embryo and larvae. Moreover, the proportion of diuron metabolites (DCPMU and DCPU) was increased in fish, but the proportion of diuron was decreased with the increasing of exposure concentration. Diuron, DCPMU, and DCPU was identified as aryl hydrocarbon receptor agonist (AhR) agonist using in silico and in vivo models. DCPMU and DCPU induced the gene expression of AhR signaling and metabolizing enzymes (such as cyp1a1) in the livers. A great deal of major metabolites affected various organs related to HPGL axis of male marine medaka and led to serious reproductive disorders. Consequently, it reveals that long-term exposure to environmentally relevant concentrations of diuron and even AhR agonist pesticides pose a potential ecological risk for marine fish., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The herbicide diuron is extensively used in the agriculture sector and is detected widely in the environment. Although several studies on the degradation of diuron by aerobic microorganisms have been reported, the degradation of diuron by anaerobic microorganisms has not been received much attention. Also, no pure culture that can degrade diuron under anaerobic conditions has yet been reported. The evaluation of diuron degradation in the soil and sediment slurries showed that diuron led to a decrease in the biodiversity of the bacterial communities. Two mixed bacterial cultures, one from the soil and the other from sediment slurries, were isolated from the enrichment media under anaerobic conditions. After 30 days of incubation at 30 °C, the mixed bacterial culture from the soil degraded 84.5 ± 5.5%, and that from the sediment slurry degraded 94.5 ± 3.0% of diuron in liquid mineral medium at an initial concentration of 20 mg/L. 1-(3,4-dichlorophenylurea (DCPU), 3-(3-chlorophenyl)-1,1-dimethylurea (CPDMU), and 3,4-dichloroaniline (3,4-DCA) were the major diuron metabolites produced by both the indigenous microorganisms and the isolated bacteria., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Freshwater biofilms have been increasingly used during the last decade in ecotoxicology due to their ecological relevance to assess the effect(s) of environmental stress at the community level. Despite growing knowledge about the effect of various stressors on the structure and the function of these microbial communities, a strong research effort is still required to better understand their response to chemical stress and the influence of environmental stressors in this response. To tackle this challenge, untargeted metabolomics is an approach of choice because of its capacity to give an integrative picture of the exposure to multiple stress and associated effect as well as identifying the molecular pathways involved in these responses. In this context, the present study aimed to explore the use of an untargeted metabolomics approach to unravel at the molecular/biochemical level the response of the whole biofilm to chemical stress and the influence of various environmental factors in this response. To this end, archived high-resolution mass spectrometry data from previous experiments at our laboratory on the effect of the model photosynthesis inhibitor diuron on freshwater biofilm were investigated by using innovative solutions for OMICs data (e.g., DRomics) and more usual chemometric approaches (multivariate and univariate statistical analyses). The results showed a faster (1 min) and more sensitive response of the metabolome to diuron than usual functional descriptors, including photosynthesis. Also, the metabolomics response to diuron resulted from metabolites following various trends (increasing, decreasing, U/bell shape) along increasing concentration and time. This metabolomics response was influenced by the temperature, photoperiod, and flow. A focus on a plant-specific omega-3 (eicosapentaenoic acid) playing a key role in the trophic chain highlighted the potential relevance of metabolomics approach to establish the link between molecular alteration and ecosystem structure/functioning impairment but also how complex is the response and the influence of all the tested factors on this response at the metabolomics level. Altogether, our results underline that more fundamental researches are needed to decipher the metabolomics response of freshwater biofilm to chemical stress and its link with physiological, structural, and functional responses toward the unraveling of adverse outcome pathways (AOP) for key ecosystem functions (e.g., primary production)., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The phenylurea herbicides are persistent in soil and water, making necessary the de-velopment of techniques for their removal from the environment. To identify new options in this regard, bacterial strains were isolated from a soil historically managed with pesticides. Ochrobactrum anthropi CD3 showed the ability to remove completely herbicides such as diuron, linuron, chlorotoluron and fluometuron from aqueous solution, and up to 89% of isoproturon. In the case of diuron and linuron, their main metabolite, 3,4-dichloroaniline (3,4-DCA), which has a higher toxicity than the parent compounds, was formed, but remained in solution without further degradation. O. anthropi CD3 was also tested for bioremediation of two different agricultural soils artificially contaminated with diuron, employing bioremediation techniques: (i) biostimulation, using a nutrient solution (NS), (ii) bioaugmentation, using O. anthropi CD3, and iii) bioavailability enhancement using 2-hydroxypropyl-β-cyclodextrin (HPBCD). When bioaugmentation and HPBCD were jointly applied, 50% of the diuron initially added to the soil was biodegraded in a range from 4.7 to 0.7 d. Also, 3,4-DCA was degraded in soil after the strain was inoculated. At the end of the soil biodegradation assay an ecotoxicity test confirmed that after inoculating O. anthropi CD3 the toxicity was drastically reduced.

The herbicides diuron, hexazinone, and sulfometuron-methyl present a potential risk of environmental contamination and are widely used for weed control in sugarcane cultivation. Our objectives were to measure the tolerance of Canavalia ensiformes (L.) DC., Stilizobium aterrimum L., Raphanus sativus L., Crotalaria spectabilis Röth, Lupinus albus L., and Pennisetum glaucum (L.) R. Br. To the herbicides diuron, hexazinone, and sulfometuron-methyl to assess the capacity of these species to extract and accumulate the herbicides in their tissues. Before sowing the green manure species, the soils were individually contaminated with the three 14 C-radiolabeled herbicides. 14 C-diuron and 14 C-sulfometuron-methyl showed higher values remaining in the soil (>90%) for all species of green manure compared to hexazinone (<80%). The green manure species analyzed showed greater potential to remedy soils contaminated with hexazinone than the other herbicides. C. ensiformes showed high phytoextraction of hexazinone when compared to the other species, removing 11.2% of the pollutant from the soil, followed by L. albus (8.6%), S. aterrimum (7.3%), R. sativus (4.8%), C. spectabilis (2.5%), and P. glaucum (1.1%). The results indicate that the phytoextraction of diuron, hexazinone and sulfometuron-methyl is dependent on the species of green manure and can be an important tool for the decontamination of areas polluted by these herbicides., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The green microalgae Parachlorella kessleri RA-002 isolated in Armenia can produce biohydrogen (H 2 ) during oxygenic photosynthesis. Addition of protonophores, carbonyl cyanide m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNF) enhances H 2 yield in P. kessleri. The maximal H 2 yield of ~2.20 and 2.08 mmol L -1 was obtained in the presence of 15 μM CCCP and 50 μM DNF, respectively. During dark conditions H 2 production by P. kessleri was not observed even in the presence of protonophores, indicating that H 2 formation in these algae was mediated by light conditions. The enhancing effect of protonophores can be coupled with dissipation of proton motive force across thylakoid membrane in P. kessleri, facilitating the availability of protons and electrons to [Fe-Fe]-hydrogenase, which led to formation of H 2 . At the same time H 2 production was not observed in the presence of diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea), a specific inhibitor of PS II. Moreover, diuron inhibits H 2 yield in P. kessleri in the presence of protonophores. The inhibitory effect of diuron coupled with suppression of electron transfer from PS II. The results showed that in these algae operates PS II-dependent pathway of H 2 generation. This study is important for understanding of the mechanisms of H 2 production by green microalgae P. kessleri and developing of its biotechnology., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The endophytic bacteria live in close nuptial relationship with the host plant. The stress experienced by the plant is expected to be transferred to the endophytes. Thus, plants thriving at polluted sites are likely to harbor pollutant-degrading endophytes. The present study reports the isolation of phenylurea herbicides assimilating Bacillus sps. from Parthenium weed growing at diuron-contaminated site. The isolated endophytes exhibited plant growth-promoting (PGP) activities. Among five isolated diuron-degrading endophytes, the most efficient isolate Bacillus licheniformis strain SDS12 degraded 85.60 ± 1.36% of 50 ppm diuron to benign form via formation of degradation intermediate 3, 4-dichloroaniline (3,4-DCA). Cell-free supernatant (CFS) obtained after diuron degradation by strain SDS12 supported algal growth comparable with the pond water. The chlorophyll content and photosynthetic efficiency of green algae decreased significantly in the presence of diuron-contaminated water; however, no such change was observed in CFS of strain SDS12, thus, suggesting that strain SDS12 can be applied in aquatic bodies for degrading diuron and reducing diuron toxicity for primary producers. Further, the use of PGP and diuron-degrading bacteria in agriculture fields will not only help in remediating the soil but also support plant growth.

In response to the potential threats stemming from the constantly increasing consumption of herbicides, bioremediation offers a beneficial technology for reducing the widespread herbicide contamination. In order to facilitate the in-situ degradation of diuron, Arthrobacter globiformis D47 is captured onto a biocompatible carrier to assemble the microorganism-immobilized silkworm excrement (MSE) composites. By characterization, bacterial cells are intensively entrapped in/onto the carriers, showing high survival and stable catalytic degradation of target pollutants. Meanwhile, MES composites display excellent adaptiveness and feasibility under different conditions, and the average half-life of diuron is shortened to 7.69 d in sugarcane field where diuron is regularly sprayed for weed management. Importantly, we assess that the use of MSE may generally boost the overall xenobiotic-degrading ability, likely due to the slight alternation of the diversity and composition of soil microbial communities. Taking together, the presented MSE provides an attractive in situ approach for the efficient diuron removal as well as for the more feasible utilization of various pollutant-degrading microorganisms., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

The present work is dedicated to the development of a lab-on-chip (LOC) device for water toxicity environmental analysis and more especially herbicide detection. The final goal is focused on the functional integration of three-electrode electrochemical microcells (ElecCell) and organic photodetectors (OPD) in order to perform simultaneously electrochemical and optical detection in the frame of algal metabolism monitoring. Considering three different algae, ie. Chlamydomonas reinhardtii, Pseudokirchneriella subcapitata and Chlorella vulgaris while dealing with photosynthesis, the multi-microsensor platform enables to measure the variations of microalgae fluorescence as well as oxygen production. It is applied to study the Diuron herbicide influences on algal metabolism, evidencing fluorescence enhancement and oxygen production inhibition for concentrations as low as few tens of nanomoles. These results are performed with unconcentrated and six time concentrated algae solutions respectively, to estimate the ability of this dual-sensor system to conduct measurements without any sample preparation. Thus, according to the obtained results, the proposed LOC device is fully adapted to the electrochemical/optical dual detection for on-site pollutant analysis, ie. without sample pre-treatment., (Copyright © 2019. Published by Elsevier B.V.)

The use of pesticides has been increasing due to the great agricultural production worldwide. The pesticides are used to eradicate pests and weeds; however, these compounds are classified as toxic to non-target organisms. Atrazine and diuron are herbicides widely used to control grassy and broadleaf weeds and weed control in agricultural crops and non-crop areas. Heavy metals are also important environmental contaminants that affect the ecological system. This study aimed to investigate the presence of herbicides-degrading genes and heavy metal resistance genes in bacterial isolates from two different soil samples from two Brazilian regions and to determine the genetic location of these genes. In this study, two isolates were obtained and identified as Escherichia fergusonii and Bacillus sp. Both isolates presented atzA, atzB, atzC, atzD, atzE, atzF, puhA, and copA genes and two plasmids each, being the major with ~ 60 Kb and a smaller with ~ 3.2 Kb. Both isolates presented the atzA-F genes inside the larger plasmid, while the puhA and copA genes were detected in the smaller plasmid. Digestion reactions were performed and showed that the ~ 60-Kb plasmid presented the same restriction profile using different restriction enzymes, suggesting that this plasmid harboring the complete degradation pathway to atrazine was found in both isolates. These results suggest the dispersion of these plasmids and the multi-herbicide degradation potential in both isolates to atrazine and diuron, which are widely used in different culture types worldwide.

Biofilms are considered as good bioindicators of contamination by means of their capacity to react quickly to xenobiotics exposure, and their pivotal role in sustaining the aquatic trophic web. The exchanges of dissolved substances between water column and biofilm can be modulated by flow velocity. This study deals with toxicokinetic (transfer mechanisms) and toxicodynamic (effects) modelling of pesticides under two contrasted flow conditions. Diuron was used to run a 2-h kinetic study on mature biofilms in river channels. Two flow conditions were considered (⋘1 cm·s -1 : lentic environments such as ponds, 2 cm·s -1 : lotic environments such as watercourses). Three concentrations were tested in order to estimate contamination levels in biofilms: 0, 5 (environmentally relevant concentration) and 50 (to determine the concentration effect) μg·L -1 . The effect of the above-mentioned factors was also assessed on biofilms photosynthesis inhibition. For successive sampling times between 0 and 2 h, the raw biofilms and EPS tightly bound to cells plus microorganisms (T-EPS-M), were physically separated and analysed for diuron accumulation and structural and functional microbial descriptors. Diuron amounts accumulated in biofilm increased with increasing diuron exposure. Biofilms accumulated higher amounts of diuron at the lower flow velocity compared to high flow for raw biofilms, while accumulation in the T-EPS-M fraction was similar between flow conditions. Consequently, both flow velocity and diuron exposure had an influence on diuron bioaccumulation and distribution. Photosynthesis inhibition over time was directly linked to the exposure concentration of diuron recorded in the T-EPS-M fraction. These results suggest that flow causes a loss of organic matter in biofilms, decreasing the total accumulation of diuron, especially within diffusible EPS. As pesticide distribution in biofilm is a major factor in the onset of toxicity, the novel fractioning method presented here will improve further toxicokinetic and toxicodynamic studies dealing with biofilms exposed to organic toxicants., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Biofilms are excellent bioindicators for water quality assessment because of their ability to integrate contamination, and their position at the base of the trophic chain in aquatic environments. Pesticides are ubiquitous in aquatic environments and can constantly interact with aquatic organisms, including those that make up biofilms, at fluctuating concentrations. The aim of this study was to describe pesticide behaviour in biofilms. Previous research highlighted that contaminant sorption was not always linear, but no study considered organic bioaccumulation isotherms and toxic impacts to biofilms concurrently. In order to characterize pesticide sorption isotherms in biofilms and the mechanisms involved in the uptake process, we simultaneously assessed bioaccumulation and toxic impact of diuron (a photosynthesis inhibiting herbicide) at the water-biofilm concentrations equilibrium. Mature biofilms grown on glass slides during one month were subsequently exposed in channels to 7 increasing concentrations of diuron from 1 to 500 μg·L -1 , plus a control condition, for 2 h with a flow velocity of 2 cm·s -1 . Then, a Langmuir isotherm equation was fitted to the bioaccumulation data, and an E max model to toxic impact results. This study established that diuron bioaccumulation in biofilm is nonlinear, and allowed to calculate the Langmuir constant and maximal concentration of diuron potentially accumulated in biofilm (up to 17,771 μg·g -1 ). In turn, we found that photosynthetic inhibition followed classical dose-response patterns with diuron concentrations in the water, and that EC 50 could be established at 75 μg·L -1 . A continuous diffusion phenomenon was thus demonstrated but it was not linearly correlated to bioaccumulation, highlighting complex uptake mechanisms operating within the matrix. The coupling of toxicokinetic and toxicodynamic approaches provided original information about pesticide behaviour and impact in periphytic microorganisms., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A huge variety of organic microcontaminants are presently detected in freshwater ecosystems, but there is still a lack of knowledge about their interactions, either with living organisms or with other contaminants. Actually, carbon nanomaterials like fullerenes (C 60 ) can act as carriers of organic microcontaminants, but their relevance in processes like bioaccumulation and biotransformation of organic microcontaminants by organisms is unknown. In this study, mesocosm experiments were used to assess the bioaccumulation and biotransformation of three organic microcontaminants (venlafaxine, diuron and triclosan) in river biofilms, and to understand how much the concomitant presence of C 60 at environmental relevant concentrations could impact these processes. Results indicated that venlafaxine exhibited the highest bioaccumulation (13% of the initial concentration of venlafaxine in water), while biotransformation was more evident for triclosan (5% of the initial concentration of triclosan in water). Furthermore, biotransformation products such as methyl-triclosan were also present in the biofilm, with levels up to 42% of the concentration of accumulated triclosan. The presence of C 60 did not involve relevant changes in the bioaccumulation and biotransformation of microcontaminants in biofilms, which showed similar patterns. Nevertheless, the study shows that a detailed evaluation of the partition of the organic microcontaminants and their transformation products in freshwater systems are important to better understand the impact of the co-existence of others microcontaminants, like carbon nanomaterials, in their possible routes of bioaccumulation and biotransformation., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The white rot basidiomycete Ganoderma lucidum was evaluated for its capability to tolerate and to degrade the herbicide diuron. Diuron at a subtoxic concentration was added at the start of the cultivation in glucose liquid stationary cultures. Under this condition diuron was a laccase inducer. Almost 50% of the initially present diuron was removed after 15 d of cultivation. Two diuron metabolites were found N'-(3,4-dichlorophenyl)-N-methylurea (DCPMU) and 3,4-dichlorophenylurea (DCPU). The addition of the cytochrome P450 inhibitors 1-aminobenzotriazole and piperonyl butoxide reduced significantly the capability of the fungus in degrading diuron. The activities of superoxide dismutase and catalase were significantly increased in the mycelial extracts by the presence of diuron. On the other hand, diuron did not cause any significant alteration in the levels of reactive oxygen species. Additionally, laccase could also degrade diuron in vitro and this degradation was increased by the addition of synthetic mediators, 3-ethylbenzthiazoline-6-sulphonic acid and acetylacetone. Significant reduction in the toxicity, as evaluated by the Lactuca sativa bioassay, was observed after G. lucidum treatment. In conclusion, G. lucidum is able to metabolize diuron by intra- and extracellular mechanisms, without the accumulation of toxic products., (Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Diuron is one of the most used herbicide in the world, and its field application has been particularly increased in Brazil due to the expansion of sugarcane crops. Diuron has often been detected in freshwater ecosystems and it can be biodegraded into three main metabolites in the environment, the 3,4-dichloroaniline (DCA), 3,4-dichlorophenylurea (DCPU) and 3,4-dichlorophenyl-N-methylurea (DCPMU). Negative effects under aquatic biota are still not well established for diuron, especially when considering its presence in mixture with its different metabolites. In this study, we evaluated the effects of diuron alone or in combination with its metabolites, DCPMU, DCPU and 3,4-DCA on biochemical stress responses and biotransformation activity of the fish Oreochromis niloticus. Results showed that diuron and its metabolites caused significant but dispersed alterations in oxidative stress markers and biotransformation enzymes, except for ethoxyresorufin-O-deethylase (EROD) activity, that presented a dose-dependent increase after exposure to either diuron or its metabolites. Glutathione S-transferase (GST) activity was significant lower in gills after exposure to diuron metabolites, but not diuron. Diuron, DCPMU and DCA also decreased the multixenobiotic resistance (MXR) activity. Lipid peroxidation levels were increased in gill after exposure to all compounds, indicating that the original compound and diuron metabolites can induce oxidative stress in fish. The integration of all biochemical responses by the Integrated Biomarker Response (IBR) model indicated that all compounds caused significant alterations in O. niloticus, but DCPMU caused the higher alterations in both liver and gill. Our findings imply that diuron and its metabolites may impair the physiological response related to biotransformation and antioxidant activity in fish at field concentrations. Such alterations could interfere with the ability of aquatic animals to adapt to environments contaminated by agriculture., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The phenylurea herbicide diuron is persistent in soil, water and groundwater and is considered to be a highly toxic molecule. The principal product of its biodegradation, 3,4-dichloroaniline, exhibits greater toxicity than diuron and is persistent in the environment. Five diuron degrading microbial consortia (C1C5), isolated from different agricultural soils, were investigated for diuron mineralization activity. The C2 consortium was able to mineralize 81.6% of the diuron in solution, while consortium C3 was only able to mineralize 22.9%. Isolated consortia were also tested in soil slurries and in all cases, except consortium C4, DT 50 (the time required for the diuron concentration to decline to half of its initial value) was drastically reduced, from 700 days (non-inoculated control) to 546, 351, and 171 days for the consortia C5, C2, and C1, respectively. In order to test the effectiveness of the isolated consortium C1 in a more realistic scenario, soil diuron mineralization assays were performed under static conditions (40% of the soil water-holding capacity). A significant enhancement of diuron mineralization was observed after C1 inoculation, with 23.2% of the herbicide being mineralized in comparison to 13.1% for the control experiment. Hydroxypropyl-β-cyclodextrin, a biodegradable organic enhancer of pollutant bioavailability, used in combination with C1 bioaugmentation in static conditions, resulted in a significant decrease in the DT 50 (214 days; 881 days, control experiment). To the best of our knowledge, this is the first report of the use of soil-isolated microbial consortia in combination with cyclodextrins proposed as a bioremediation technique for pesticide contaminated soils., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Diuron and its biodegradation metabolites were recently reported to cause alterations in plasma steroid hormone concentrations with subsequent impacts on reproductive development in fish. Since steroid hormone biosynthesis is regulated through neurotransmission of the central nervous system (CNS), studies were conducted to determine whether neurotransmitters that control hormone biosynthesis could be affected after diuron and diuron metabolites treatment. As the same neurotransmitters and steroid hormones regulate behavioral outcomes, aggression was also evaluated in male Nile tilapia (Oreochromis niloticus). Male tilapias were exposed for 10 days to waterborne diuron and the metabolites 3,4-dichloroaniline (DCA), 3,4-dichlorophenyl-N-methylurea (DCPMU), at nominal concentrations of 100 ng L -1 . In contrast to Diuron, DCA and DCPMU significantly diminished plasma testosterone concentrations (39.4% and 36.8%, respectively) and reduced dopamine levels in the brain (47.1% and 44.2%, respectively). In addition, concentrations of the stress steroid, cortisol were increased after DCA (71.0%) and DCPMU (57.8-%) exposure. A significant decrease in aggressive behavior was also observed in animals treated with the metabolites DCA (50.9%) and DCPMU (68.8%). These results indicate that biotransformation of diuron to active metabolites alter signaling pathways of the CNS which may impact androgen and the stress response as well as behavior necessary for social dominance, growth, and reproduction., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A diuron-degrading endophyte DP8-1 was isolated from sugarcane root grown in diuron-treated soil in the present study. The endophyte was identified as Neurospora intermedia based on the morphological characteristics and sequence analysis. The fermentation parameters including temperature, pH, inoculation size, carbon source, and initial diuron concentration were also investigated for the optimization of degradation efficiency. The results indicated that strain DP8-1 was capable of degrading up to 99% diuron within 3 days under the optimal degrading condition. The study of degradation spectrum indicated that strain DP8-1 could also degrade and utilize fenuron, monuron, metobromuron, isoproturon, chlorbromuron, linuron, and chlortoluron as substrate for strain growth. On basis of liquid chromatography-mass spectrometry analysis for the products of the degradation of diuron, strain DP8-1 metabolized diuron to produce N-(3,4-dichlorophenyl)-urea and N-(3,4-dichlorophenyl)-N-methylurea through sequential N-dealkylations. In a soil bioaugmentation experiment, the inoculation of strain DP8-1 into diuron-treated soil effectively enhanced the disappearance rate of diuron.

Diuron is a biologically active pollutant present in soil, water and sediments. It is persistent in soil, water and groundwater and slightly toxic to mammals and birds as well as moderately toxic to aquatic invertebrates. Its principal product of biodegradation, 3,4-dichloroaniline, exhibits a higher toxicity than diuron and is also persistent in the environment. On this basis, the objective of the study was to determine the potential capacity of a proposed novel diuron-degrading microbial consortium (DMC) for achieving not only diuron degradation, but its mineralisation both in solution as well as in soils with different properties. The consortium was tested in a soil solution where diuron was the only carbon source, and more than 98.8% of the diuron initially added was mineralised after only a few days. The consortium was composed of three diuron-degrading strains, Arthrobacter sulfonivorans, Variovorax soli and Advenella sp. JRO, the latter had been isolated in our laboratory from a highly contaminated industrial site. This work shows for the first time the potential capacity of a member of the genus Advenella to remediate pesticide-contaminated soils. However, neither of the three strains separately achieved mineralisation (ring- 14 C) of diuron in a mineral medium (MSM) with a trace nutrient solution (NS); combined in pairs, they mineralised 40% of diuron in solution, but the most relevant result was obtained in the presence of the three-member consortium, where complete diuron mineralisation was achieved after only a few days. In the presence of the investigated soils in suspension, the capacity of the consortium to mineralise diuron was evaluated, achieving mineralisation of a wide range of herbicides from 22.9 to 69.0%., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Microorganisms capable of degrading herbicides are essential to minimize the amount of chemical compounds that may leach into other environments. This work aimed to study the potential of sandy-loam soil fungi to tolerate the herbicide Herburon (50% diuron) and to degrade the active ingredient diuron. Verticillium sp. F04, Trichoderma virens F28, and Cunninghamella elegans B06 showed the highest growth in the presence of the herbicide. The evaluation of biotransformation showed that Aspergillus brasiliensis G08, Aspergillus sp. G25, and Cunninghamella elegans B06 had the greatest potential to degrade diuron. Statistical analysis demonstrated that glucose positively influences the potential of the microorganism to degrade diuron, indicating a cometabolic process. Due to metabolites founded by diuron biotransformation, it is indicated that the fungi are relevant in reducing the herbicide concentration in runoff, minimizing the environmental impact on surrounding ecosystems.

Previous studies using in vivo bioassay guided fractionation indicated that the herbicide diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and alkylphenol (AP)-containing surfactants were detected in fractions of extracts that induced the estrogenic biomarker, vitellogenin in fish exposed to surface water extracts from the United States. However, when the compounds were evaluated individually using in vivo estrogenic assays or in vitro estrogen receptor assays, estrogenic activity was not observed. Since APs have been shown to alter activity and content of cytochrome P450s (CYP) which convert diuron to potential estrogenic metabolites, the hepatic biotransformation of diuron was measured with and without a 7day pretreatment of p-Octylphenol (OP) and p-Nonylphenol (NP) at low (OP 13ng/L+NP 91ng/L), and high concentrations (OP 65ng/L+NP 455ng/L) in juvenile male Nile tilapia (Oreochromus niloticus). Pre-treatment with the OP/NP (AP) mixture caused elevated levels of NADPH-catalyzed formation of 3,4-dichlorophenyl-N-methylurea (DCPMU) but not 3,4-dichlorophenylurea (DCPU). Fish were also treated with nominal concentrations of low (40ng/L) and high (200ng/L) diuron and each of its three degradates/metabolites: DCPMU, DCPU and 3,4-dichloroaniline (DCA). Additional treatments were conducted with APs and Diuron as a mixture at the low concentrations which mimicked concentrations observed in surface waters. Hepatic vitellogenin (Vtg) mRNA was induced by exposure to the high concentrations of Diuron, as well as DCPMU and DCPU in both concentrations. Brain cytochrome P450 aromatase activity was generally diminished by diuron, its metabolites, and the AP/diuron mixtures. 17β-Hydroxysteroid dehydrogenase (17βHSD) levels were also reduced by DCPMU and DCA in the lower concentrations, but not by higher concentrations. While the AP mixture reduced 17βHSD, the AP/diuron mixture induced testosterone (T) biosynthesis at the single concentration tested. Although CYP3A expression was induced by all diuron metabolites, it was unchanged by the AP mixture. These data indicate that mixtures of AP and diuron enhanced the formation of the metabolite (DCPMU) which induced vitellogenin, and reduced T biosynthetic enzymes (17βHSD inhibition). Overall, these data showed that APs may have induced the biotransformation of diuron to at least one metabolite, that may disrupt androgen biosynthesis and potentially alter steroid feedback pathways in the central nervous system., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Herbicides are one of the major classes of pollutants contaminating coastal waters over the world. Among them, diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a phenylurea herbicide frequently detected in oyster-producing area, known to be toxic for this important exploited non-target species. With the aim to investigate the mechanisms by which diuron displays its toxicity in oyster, the implication of both biotransformation and oxygen reactive species (ROS) production was studied considering embryotoxicity and genotoxicity as endpoints. Comparative embryotoxicity and genotoxicity of diuron and its main metabolites (DCPMU, DCPU and 3,4-DCA) were thus studied on oyster larvae by the embryo-larval bioassay on D larvae and the comet assay on trochophore larvae, respectively. Exposures were also performed in presence and absence of known ROS scavenger compounds - ascorbic acid and N-acetylcysteine, to evaluate the involvement of oxyradicals in the toxic responses. In the case of diuron, the production of ROS on exposed oyster larvae was also measured using 2',7'-dichlorodihydrofluorescein diacetate as a probe for flow cytometric analysis. The results we obtained showed the embryotoxicity and genotoxicity of diuron and its metabolites in early life stages of the Pacific oyster. For concentrations ranging from 0.05 to 0.5μgL(-1), diuron appeared significantly more embryotoxic than DCPMU and DCPU (p<0.001). Embryotoxicity decreased with diuron metabolism as follows: diuron≥DCPMU=DCPU, highlighting that biotransformation can constitute a true detoxication pathways in oyster larvae by decreasing the toxicity of the parent compound. In the opposite, no difference was observed between diuron and its metabolites concerning larval development when considering a lower and more environmentally realistic range of concentrations (0.002-0.050μgL(-1)). 3,4-DCA was the only compound that did not show any sign of embryotoxicity, even at concentrations up to 5μgL(-1). Concerning genotoxicity, no significant difference was observed between diuron and all of its metabolites including 3, 4 DCA with damages detected from the concentration of 0.05μgL(-1). As for diuron, the toxicity of the metabolites seems to be mediated in some part by ROS production as clearly demonstrated by the decrease in genotoxicity and developmental abnormalities in the presence of the oxidant scavenger, ascorbic acid., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The present work was dedicated to the development of a lab-on-chip device for water toxicity analysis and more particularly herbicide detection in water. It consists in a portable system for on-site detection composed of three-electrode electrochemical microcells, integrated on a fluidic platform constructed on a glass substrate. The final goal is to yield a system that gives the possibility of conducting double, complementary detection: electrochemical and optical and therefore all materials used for the fabrication of the lab-on-chip platform were selected in order to obtain a device compatible with optical technology. The basic detection principle consisted in electrochemically monitoring disturbances in metabolic photosynthetic activities of algae induced by the presence of Diuron herbicide. Algal response, evaluated through oxygen (O2) monitoring through photosynthesis was different for each herbicide concentration in the examined sample. A concentration-dependent inhibition effect of the herbicide on photosynthesis was demonstrated. Herbicide detection was achieved through a range (blank - 1 µM Diuron herbicide solution) covering the limit of maximum acceptable concentration imposed by Canadian government (0.64 µM), using a halogen white light source for the stimulation of algal photosynthetic apparatus. Superior sensitivity results (limit of detection of around 0.1 µM) were obtained with an organic light emitting diode (OLED), having an emission spectrum adapted to algal absorption spectrum and assembled on the final system., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Soil organic amendment affects biotic and abiotic processes that control the fate of pesticides, but the treatment history of the soil is also relevant. These processes were assessed in a multidisciplinary study with the aim of optimizing pesticide mitigation in soils. Soil microcosms pre-treated (E2) or not with diuron (E1) were amended with either winery (W) or olive waste (O) vermicomposts. Herbicide dissipation followed a double first-order model in E1 microcosms, but a single first-order model in E2. Also, diuron persistence was longer in E1 than in E2 (E1-DT50>200 day(-1), E2-DT50<16 day(-1)). The genetic structure of the bacterial community was modified by both diuron exposure and amendment. O-vermicompost increased enzymatic activities in both experiments, but diuron-degrading genetic potential (puhB) was quantified only in E2 microcosms in accordance with reduced diuron persistence. Therefore, O-vermicompost addition favoured the proliferation of diuron degraders, increasing the soil diuron-depuration capability., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Some endocrine disrupting chemicals (EDCs) can alter the estrogenic activities of the organism by directly interacting with estrogen receptors (ER) or indirectly through the hypothalamus-pituitary-gonadal axis. Recent studies in male Nile tilapia (Oreochromis niloticus) indicated that diuron may have anti-androgenic activity augmented by biotransformation. In this study, the effects of diuron and three of its metabolites were evaluated in female tilapia. Sexually mature female fish were exposed for 25 days to diuron, as well as to its metabolites 3,4-dichloroaniline (DCA), 3,4-dichlorophenylurea (DCPU) and 3,4-dichlorophenyl-N-methylurea (DCPMU), at concentrations of 100 ng/L. Diuron metabolites caused increases in E2 plasma levels, gonadosomatic indices and in the percentage of final vitellogenic oocytes. Moreover, diuron and its metabolites caused a decrease in germinative cells. Significant differences in plasma concentrations of the estrogen precursor and gonadal regulator17α-hydroxyprogesterone (17α-OHP) were not observed. These results show that diuron metabolites had estrogenic effects potentially mediated through enhanced estradiol biosynthesis and accelerated the ovarian development of O. niloticus females., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

From agricultural soils, where the herbicide Diuron has been frequently applied, a microbial community capable of degrading Diuron and 3,4-dichloroaniline was obtained. The volumetric rates and degradation efficiencies of Diuron and 3,4-DCA were evaluated in two distinct biofilm reactors, which differ in their operating conditions. One is a horizontal fixed bed reactor; plug-flow operated (PF-PBC) with severe limitation of oxygen. In this reactor, the air was supplied to an equalizer reservoir at the start of the PF-PBC reactor. The other is a compartmentalized aerobic biobarrier with internal recirculation of liquid aerated through airlift devices (ALB), continuously or intermittently operated. Both reactors were inoculated with a microbial community capable of degrading Diuron, isolated from a sugarcane field. In the oxygen-limited PF-PBC reactor, 3,4-DCA accumulation was detected, mainly in the middle zone of the packed channel. On the contrary, in the fully aerobic ALB reactor, minimal accumulation of catabolic byproducts was detected, and high Diuron removal efficiencies and removal rates were obtained when it was continuously operated in steady-state conditions. Additionally, the influence of oxygen limitation on the kinetic behavior of the PF-PBC reactor was determined, and a method to estimate the local removal rates of Diuron RV,CD along the plug-flow channel is described. It was observed that the local values of the instantaneous removal rate of Diuron dCD/dt are high in the aerobic region of the PF-PBC reactor; but, suddenly decay in the reactor zones limited by dissolved oxygen., (Copyright © 2015 Elsevier B.V. All rights reserved.)

This investigation was undertaken to determine the interaction of diuron with human serum albumin (HSA) was studied by monitoring the spectral behavior of diuron-HSA system. The fluorescence of HSA at 340 nm excited at 230 nm was obviously quenched by diuron due to dynamic collision and the quenching constant was of the order of 10(4) L mol(-1) at 310 K. However, no fluorescence quenching was observed when excited at 280 nm. Thermodynamic investigations revealed that the combination between diuron and HSA was entropy driven by predominantly hydrophobic interactions. The binding of diuron induced the drastic reduction in α-helix conformation and the significant enhancement in β-turn conformation of HSA. In addition, both sites marker competition study and molecular modeling simulation evidenced the binding of diuron to HSA primarily took place in subdomain IIIA (Sudlow's site II).

An amphiphilic carboxymethyl chitosan conjugate with photolabile 2-nitrobenzyl side groups (NBS-CMCS) was synthesized, which could self-assemble into polymeric micelles in aqueous condition following by adding dropwise dialdehyde to form a cross-linking structure. TEM and (1)H NMR confirmed that the cross-linked micelles had a core-shell configuration with an average diameter of 140 ± 5.5 nm. DLS and TEM observations showed that the cross-linked micelles were stable in aqueous solution at pH 7.0 without light irradiation, while they could transfer into nanocapsules upon exposure to 365 nm UV light. Diuron, a photosynthetic inhibitor, was encapsulated in the cross-linked micelles reaching encapsulation efficiency as much as 91.9%. No release of the encapsulated diuron was detected without light, whereas a release rate as high as 96.8% over 8h at pH 7.0 buffer was observed under solar stimulated irradiation, indicating that the cross-linked micelles may be used as a photo-controlled sustained release carrier for the delivery of photosynthetic inhibitor., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a widely used herbicide which has been frequently detected in surface waters throughout the world. In vivo bioassay guided fractionation studies indicated that diuron may have estrogenic activity augmented by biotransformation. This study evaluated the effects of diuron and three of its metabolites on plasma hormone concentrations and spermatogenesis of the freshwater fish Nile tilapia (Oreochromis niloticus). Sexually mature male fish were exposed for 25 days to diuron, as well to its metabolites 3,4-dichloroaniline (DCA), 3,4-dichlorophenylurea (DCPU) and 3,4-dichlorophenyl-N-methylurea (DCPMU), at concentrations of 200ng/L. Testosterone levels were decreased by diuron, but had limited effects on gonadal histology. Diuron metabolites, however, caused significant decreases in testosterone and in 11-ketotestosterone, gonadosomatic index, diameter of seminiferous tubules and in the mean percentages of germ cells (spermatids and spermatozoa). We conclude that these metabolites have antiandrogenic activity to male Nile tilapia, potentially causing reproductive impairment in male fish., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The amidohydrolase superfamily has remarkable functional diversity, with considerable structural and functional annotation of known sequences. In microbes, the recent evolution of several members of this family to catalyze the breakdown of environmental xenobiotics is not well understood. An evolutionary transition from binuclear to mononuclear metal ion coordination at the active sites of these enzymes could produce large functional changes such as those observed in nature, but there are few clear examples available to support this hypothesis. To investigate the role of binuclear-mononuclear active-site transitions in the evolution of new function in this superfamily, we have characterized two recently evolved enzymes that catalyze the hydrolysis of the synthetic herbicides molinate (MolA) and phenylurea (PuhB). In this work, the crystal structures, mutagenesis, metal ion analysis, and enzyme kinetics of both MolA and PuhB establish that these enzymes utilize a mononuclear active site. However, bioinformatics and structural comparisons reveal that the closest putative ancestor of these enzymes had a binuclear active site, indicating that a binuclear-mononuclear transition has occurred. These proteins may represent examples of evolution modifying the characteristics of existing catalysts to satisfy new requirements, specifically, metal ion rearrangement leading to large leaps in activity that would not otherwise be possible., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

A study on the acute and chronic effects of the herbicide diuron was carried out. The test, basing on a yeast cell probe, investigated the interference with cellular catabolism and possible self-detoxification capacity of Saccharomyces cerevisiae. Aerobic respiration was taken as the toxicological end-point. Percentage interference (%r) with cellular respiration was measured in water by increased dissolved O2 concentration (ppm) after exposure to different doses. Interference was calculated through the comparison of respiratory activity of exposed and non-exposed cells. Short-term and long-term (6 and 24 h respectively) exposures were also considered. The test for short-term exposure gave positive %r values except that for 10-6 M (11.11%, 11.76%, 13.33% and 0% for 10-10 M, 10-8 M, 10-7 M and 10-6 M respectively). In the case of long-term exposure the test showed positive %r values, but less effect than short-term exposure until 10-8 M and much higher at 10-6 M (7.41%, 8.82%, 11.76% and 6.06% for 10-10 M, 10-8 M, 10-7 M and 10-6 M respectively). The findings of aerobic respiration as toxicological end-point were in agreement with known mechanisms of toxicity and intracellular detoxification for both the doses and exposure times employed.

This study examined the effects of diuron on strains of three major freshwater diatom species, Eolimna minima, Nitzschia palea and Planothidium lanceolatum. These species are frequently recorded in the Morcille River, where diuron runs off during phytosanitary treatments of the vineyards around. Here, there were three diatom exposure groups for each species: 0, 1 and 10 μg/L diuron during a 14-day laboratory assessment. Diuron water concentration, cell number, photosynthetic activity and gene expression were assessed at 6 h and 2, 7 and 14 days after contamination. Diuron exposure altered photosynthetic activity in that the optimal quantum yield of photosystem II (PSII) decreased between 40 and 50% and, for P. lanceolatum at 10 μg/L, there was complete inhibition. Genetic responses indicated diuron effects on both photosystem II and mitochondrial metabolism in all three species at both diuron exposure levels. Thus, analysis of the expression of psaA, d1, cox1, nad5 and 12s could be an early biomarker to detect pesticide pollution. Overall, this study revealed differences in diuron sensitivity among the three species: E. minima and N. palea appeared to be more tolerant than P. lanceolatum. These results suggest that the development of molecular tools, and more precisely of biomarkers, will aid in early assessment of contamination and water quality.

Diuron was found to be mineralized in buffer strip soil (BS) and in the sediments (SED) of the Morcille river in the Beaujolais vineyard repeatedly treated with this herbicide. Enrichment cultures from BS and SED samples led to the isolation of three bacterial strains transforming diuron to 3,4-dichloroaniline (3,4-DCA) its aniline derivative. 16S rRNA sequencing revealed that they belonged to the genus Arthrobacter (99% of similarity to Arthrobacter globiformis strain K01-01) and were designated as Arthrobacter sp. BS1, BS2 and SED1. Diuron-degrading potential characterized by sequencing of the puhA gene, characterizing the diuron-degradaing potential, revealed 99% similarity to A. globiformis strain D47 puhA gene isolated a decade ago in the UK. These isolates were also able to use chlorotoluron for their growth. Although able to degrade linuron and monolinuron to related aniline derivatives they were not growing on them. Enrichment cultures led to the isolation of a strain from the sediments entirely degrading 3,4-DCA. 16S rRNA sequence analysis showed that it was affiliated to the genus Achromobacter (99% of similarity to Achromobacter sp. CH1) and was designated as Achromobacter sp. SP1. The dcaQ gene encoding enzyme responsible for the transformation of 3,4-DCA to chlorocatechol was found in SP1 with 99% similarity to that of Comamonas testosteroni WDL7. This isolate also used for its growth a range of anilines (3-chloro-4-methyl-aniline, 4-isopropylaniline, 4-chloroaniline, 3-chloroaniline, 4-bromoaniline). The mixed culture composed of BS2 and SP1 strains entirely mineralizes (14)C-diuron to (14)CO2. Diuron-mineralization observed in the enrichment culture could result from the metabolic cooperation between these two populations., (Copyright © 2014. Published by Elsevier Ltd.)

An autonomous electrochemical biosensor with three electrodes integrated on the same silicon chip dedicated to the detection of herbicides in water was fabricated by means of silicon-based microfabrication technology. Platinum (Pt), platinum black (Pt Bl), tungsten/tungsten oxide (W/WO3) and iridium oxide (Pt/IrO2) working ultramicroelectrodes were developed. Ag/AgCl and Pt electrodes were used as reference and counter-integrated electrodes respectively. Physical vapor deposition (PVD) and electrodeposition were used for thin film deposition. The ultramicroelectrodes were employed for the detection of O2, H2O2 and pH related ions H3O(+)/OH(-), species taking part in photosynthetic and metabolic activities of algae. By measuring the variations in consumption-production rates of these electroactive species by algae, the quantity of herbicides present at trace level in the solution can be estimated. Fabricated ultramicroelectrodes were electrochemically characterized and calibrated. Pt Black ultramicroelectrodes exhibited the greatest sensitivity regarding O2 and H2O2 detection while Pt/IrO2 ultramicroelectrodes were more sensitive for pH measurement compared to W/WO3 ultramicroelectrodes for pH measurement. Bioassays were then conducted to detect traces of Diuron herbicide in water samples by evaluating disturbances in photosynthetic and metabolic activities of algae caused by this herbicide., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Fungi have been recently recognized as organisms able to grow in presence of high salt concentration with halophilic and halotolerance properties and their ligninolytic enzyme complex have an unspecific action enabling their use to degradation of a number of xenobiotic compounds. In this work, both the effect of salt and polyols on growth of the basidiomycetes strains, on their ability to produce ligninolytic enzyme and diuron degradation were evaluated. Results showed that the presence of NaCl in the culture medium affected fungal specimens in different ways. Seven out of ten tested strains had growth inhibited by salt while Dacryopinax elegans SXS323, Polyporus sp MCA128 and Datronia stereoides MCA167 fungi exhibited higher biomass production in medium containing 0.5 and 0.6 mol.L(-1) of NaCl, suggesting to be halotolerant. Polyols such as glycerol and mannitol added into the culture media improved the biomass and ligninases production by D. elegans but the fungus did not reveal consumption of these polyols from media. This fungus degraded diuron in medium control, in presence of NaCl as well as polyols, produced MnP, LiP and laccase.

Bioremediation of pesticide-polluted soil may be more efficient using mixed fungal-bacterial cultures rather than the individual strains alone. This may be due to cooperative catabolism, where the first organism transforms the pollutant to products which are then used by the second organism. In addition, fungal hyphae may function as transport vectors for bacteria, thereby facilitating a more effective spreading of degrader organisms in the soil. A more rapid mineralization of the phenylurea herbicide diuron was found in sand with added microbial consortia consisting of both degrading bacteria and fungi. Facilitated transport of bacteria by fungal hyphae was demonstrated using a system where herbicide-spiked sand was separated from the consortium by a layer of sterile glass beads. Several fungal-bacterial consortia were investigated by combining different diuron-degrading bacteria (Sphingomonas sp. SRS2, Variovorax sp. SRS16, and Arthrobacter globiformis D47) and fungi (Mortierella sp. LEJ702 and LEJ703). The fastest mineralization of (14)C-labeled diuron was seen in the consortium consisting of Mortierella LEJ702, Variovorax SRS16, and A. globiformis D47, as measured by evolved (14)CO2. In addition, the production of diuron metabolites by this consortium was minimal. Analyses of 16S rDNA suggested that bacteria were transported more efficiently by LEJ702 than by LEJ703. Finally, it was determined that the fungal growth differed for LEJ702 and LEJ703 in the three-member consortia. This study demonstrates new possibilities for applying efficient fungal-bacterial consortia for bioremediation of polluted soil., (© 2013.)

Diuron is carcinogenic to the rat urinary bladder at high dietary levels. The proposed mode of action (MOA) for diuron is urothelial cytotoxicity and necrosis followed by regenerative urothelial hyperplasia. Diuron-induced urothelial cytotoxicity is not due to urinary solids. Diuron is extensively metabolized, and in rats, N-(3,4-dichlorophenyl)urea (DCPU) and 4,5-dichloro-2-hydroxyphenyl urea (2-OH-DCPU) were the predominant urinary metabolites; lesser metabolites included N-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and trace levels of 3,4-dichloroaniline (DCA). In humans, DCPMU and DCPU have been found in the urine after a case of product abuse. To aid in elucidating the MOA of diuron and to evaluate the metabolites that are responsible for the diuron toxicity in the bladder epithelium, we investigated the urinary concentrations of metabolites in male Wistar rats treated with 2500ppm of diuron, the urothelial cytotoxicity in vitro of the metabolites and their gene expression profiles. DCPU was found in rat urine at concentrations substantially greater than the in vitro IC50 and induced more gene expression alterations than the other metabolites tested. 2-OH-DCPU was present in urine at a concentration approximately half of the in vitro IC50, whereas DCPMU and DCA were present in urine at concentrations well below the IC50. For the diuron-induced MOA for the rat bladder, we suggest that DCPU is the primary metabolite responsible for the urothelial cytotoxicity with some contribution also by 2-OH-DCPU. This study supports a MOA for diuron-induced bladder effects in rats consisting of metabolism to DCPU (and 2-OH-DCPU to a lesser extent), concentration and excretion in urine, urothelial cytotoxicity, and regenerative proliferation., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Microbial pesticide degradation studies have until now mainly focused on bacteria, although fungi have also been shown to degrade pesticides. In this study we clarify the background for the ability of the common soil fungus Mortierella to degrade the phenylurea herbicide diuron. Diuron degradation potentials of five Mortierella strains were compared, and the role of carbon and nitrogen for the degradation process was investigated. Results showed that the ability to degrade diuron varied greatly among the Mortierella strains tested, and the strains able to degrade diuron were closely related. Degradation of diuron was fastest in carbon and nitrogen rich media while suboptimal nutrient levels restricted degradation, making it unlikely that Mortierella utilize diuron as carbon or nitrogen sources. Degradation kinetics showed that diuron degradation was followed by formation of the metabolites 1-(3,4-dichlorophenyl)-3-methylurea, 1-(3,4-dichlorophenyl)urea and an hitherto unknown metabolite suggested to be 1-(3,4-dichlorophenyl)-3-methylideneurea.

Background: Low concentrations (10(-6)-10(-9) g L(-1)) of the herbicide diuron are occasionally detected as water contaminants in areas around the world where the herbicide is used extensively. Remediation of contaminated waters using diuron-mineralising bacteria is a possible approach for cleaning these resources. However, few diuron-mineralising strains have been isolated. Here, the ability of Sphingomonas sp. SRS2, a well-known soil bacterium capable of degrading the structurally related herbicide isoproturon, to mineralise diuron at realistically low concentrations is tested., Results: Strain SRS2 readily degraded the dimethylurea side chain, while no or only slow mineralisation of the ring structure was determined. By monitoring metabolites, it was determined that SRS2 initially degraded diuron by two successive N-demethylations followed by cleavage of the urea group to 3,4-dichloroaniline (3,4-DCA). Mineralisation of low diuron concentrations by SRS2 was detected and could be stimulated by the addition of a complex nutrient source. Further enhancement of the mineralisation activity was obtained by combining SRS2 with the 3,4-DCA-mineralising Variovorax sp. SRS16., Conclusion: This work demonstrates that Sphingomonas sp. SRS2 is a promising candidate for bioaugmentation, alone or in combination with other strains, and that enhanced diuron mineralisation at realistically low concentrations can be achieved., (© 2013 Society of Chemical Industry.)

The changes observed photosystem I activity of lettuce plants exposed to iron deficiency were investigated. Photooxidation/reduction kinetics of P700 monitored as ΔA820 in the presence and absence of electron transport inhibitors and acceptors demonstrated that deprivation in iron decreased the population of active photo-oxidizable P700. In the complete absence of iron, the addition of plant inhibitors (DCMU and MV) could not recover the full PSI activity owing to the abolition of a part of P700 centers. In leaves with total iron deprivation (0μM Fe), only 15% of photo-oxidizable P700 remained. In addition, iron deficiency appeared to affect the pool size of NADP(+) as shown by the decline in the magnitude of the first phase of the photooxidation kinetics of P700 by FR-light. Concomitantly, chlorophyll content gradually declined with the iron concentration added to culture medium. In addition, pronounced changes were found in chlorophyll fluorescence spectra. Also, the global fluorescence intensity was affected. The above changes led to an increased rate of cyclic electron transport around PSI mainly supported by stromal reductants., (Copyright © 2013 Elsevier GmbH. All rights reserved.)