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Heliyon Nov 2019Carbamates are synthetic pesticides, extensively used throughout the world due to their broad specificity against various insect pests. However, their enormous and...
Carbamates are synthetic pesticides, extensively used throughout the world due to their broad specificity against various insect pests. However, their enormous and inadequate use have made them a potential threat to the environment. At low temperature, degradation of carbamates becomes difficult mainly because of low biological activity. In the present study, we isolated a bacterial strain from a low temperature climate where the methylated carbamates are used for crop protection. The bacterium, was identified as (TA3) by 16S rRNA analysis. Degradation experiments with both free and immobilized cells in minimal salt medium indicated that the strain TA3 utilized carbaryl, carbofuran and aldicarb as both carbon and nitrogen source. TA3 can grow well at 4 °C and demonstrated the ability to degrade three carbamates (50 μgml) at low temperature. The immobilized cells were found more efficient than their free cells counter parts. Immobilized cells has ability to degrade 100% of carbamates at 30 °C while 80% at 4 °C but incase of their free cells counter parts the efficiency to degrade carbamates was less which was 60% at 4 °C and 80% at 30 °C. TA3 free cellsextract also depicted high activity against all the three carbamates even at 4 °C indicating a possible enzymatic mechanism of degradation.
PubMed: 31768430
DOI: 10.1016/j.heliyon.2019.e02740 -
Ecotoxicology and Environmental Safety Feb 2020A novel carbofuran-degrading strain CFD-1 was isolated and preliminarily identified as Sphingbium sp. This strain was able to utilize carbofuran as the sole carbon...
A novel carbofuran-degrading strain CFD-1 was isolated and preliminarily identified as Sphingbium sp. This strain was able to utilize carbofuran as the sole carbon source for growth. The carbofuran hydrolase gene cehA was cloned from strain CFD-1 and expressed in Escherichia coli. CehA could hydrolyze carbamate pesticides including carbofuran and carbaryl efficiently, while it showed poor hydrolysis ability against isoprocarb, propoxur, oxamyl and aldicarb. CehA displayed maximal enzymatic activity at 40 °C and pH 7.0. The apparent Km and Kcat values of CehA for carbofuran were 133.22 ± 5.70 μM and 9.48 ± 0.89 s-1, respectively. The site-directed mutation experiment showed that His313, His315, His453 and His495 played important roles in the hydrolysis of carbofuran by CehA. Furthermore, the sequence of cehA is highly conserved among different carbofuran-degrading strains, and there are mobile elements around cehA, indicating that it may be transferred horizontally between different strains.
Topics: Amino Acids; Biodegradation, Environmental; Carbamates; Carbaryl; Carbofuran; Hydrolases; Hydrolysis; Pesticides; Sphingomonadaceae
PubMed: 31759739
DOI: 10.1016/j.ecoenv.2019.109938 -
Applied Clay Science Feb 2019People and animals can be unintentionally exposed to complex mixtures of hazardous chemicals that can threaten the safety of food and water supplies following natural...
People and animals can be unintentionally exposed to complex mixtures of hazardous chemicals that can threaten the safety of food and water supplies following natural and man-made disasters and emergencies. Our research has focused on the development of broad-acting adsorbents that will tightly bind environmental contaminants in the gastrointestinal tract and decrease their bioavailability to humans and animals during these events. In this study, benzo[a]pyrene (BaP) and aldicarb were used as representative chemicals due to their high toxicity and extensive distribution in the environment. Both chemicals have been commonly detected in water and sediments in the US, and their distribution and concentrations can be enhanced during disasters. To address this problem, we have amended and functionalized montmorillonite clays with the nutrients, L-carnitine and choline to enhance their attraction for lipophilic toxins, such as BaP and aldicarb. Based on equilibrium isothermal analyses, we have demonstrated a significantly increased binding capacity (Qmax) and affinity (Kd) for BaP and aldicarb compared to the parent clay. Adsorption isotherms also showed that talc bound strongly to BaP with the highest Qmax, which was twice that of activated carbon. Additionally, cultures of adult hydra with a metabolism activation package were used as an toxicity indicator to confirm the ability of test adsorbents to protect against toxicity at low inclusion levels. We anticipate that the optimal adsorbents developed can be delivered in food and flavored water, or administered by sachet or capsule during emergencies and disasters to decrease human and animals exposures to environmental toxins.
PubMed: 31435120
DOI: 10.1016/j.clay.2018.11.010 -
Toxicological Sciences : An Official... Dec 2019Perfluorooctane sulfonate (PFOS) has been widely utilized in numerous industries. Due to long environmental and biological half-lives, PFOS is a major public health...
Perfluorooctane sulfonate (PFOS) has been widely utilized in numerous industries. Due to long environmental and biological half-lives, PFOS is a major public health concern. Although the literature suggests that PFOS may induce neurotoxicity, neurotoxic mechanisms, and neuropathology are poorly understood. Thus, the primary goal of this study was to determine if PFOS is selectively neurotoxic and potentially relevant to specific neurological diseases. Nematodes (Caenorhabditis elegans) were exposed to PFOS or related per- and polyfluoroalkyl substances (PFAS) for 72 h and tested for evidence of neuropathology through examination of cholinergic, dopaminergic, gamma-amino butyric acid (GABA)ergic, and serotoninergic neuronal morphologies. Dopaminergic and cholinergic functional analyses were assessed through 1-nonanol and Aldicarb assay. Mechanistic studies assessed total reactive oxygen species, superoxide ions, and mitochondrial content. Finally, therapeutic approaches were utilized to further examine pathogenic mechanisms. Dopaminergic neuropathology occurred at lower exposure levels (25 ppm, approximately 50 µM) than required to produce neuropathology in GABAergic, serotonergic, and cholinergic neurons (100 ppm, approximately 200 µM). Further, PFOS exposure led to dopamine-dependent functional deficits, without altering acetylcholine-dependent paralysis. Mitochondrial content was affected by PFOS at far lower exposure level than required to induce pathology (≥1 ppm, approximately 2 µM). Perfluorooctane sulfonate exposure also enhanced oxidative stress. Further, mutation in mitochondrial superoxide dismutase rendered animals more vulnerable. Neuroprotective approaches such as antioxidants, PFAS-protein dissociation, and targeted (mitochondrial) radical and electron scavenging were neuroprotective, suggesting specific mechanisms of action. In general, other tested PFAS were less neurotoxic. The primary impact is to prompt research into potential adverse outcomes related to PFAS-induced dopaminergic neurotoxicity in humans.
Topics: Alkanesulfonic Acids; Animals; Antioxidants; Caenorhabditis elegans; Cell Line; Dopamine; Environmental Pollutants; Fluorocarbons; Humans; Neurons; Neurotoxicity Syndromes; Oxidative Stress; Reactive Oxygen Species
PubMed: 31428778
DOI: 10.1093/toxsci/kfz191 -
Neurotoxicology Sep 2019The signal transmission in the nervous system operates through a sensitive balance between excitatory (E) inputs and inhibitory (I) responses. Imbalances in this system...
The signal transmission in the nervous system operates through a sensitive balance between excitatory (E) inputs and inhibitory (I) responses. Imbalances in this system contribute to the development of pathologies such as seizures. In Caenorhabditis elegans, the locomotor circuit operates via the coordinated activity of cholinergic excitatory (E) and GABAergic inhibitory (I) transmission. Changes in E/I inputs can cause uncontrolled electrical discharges, mimicking the physiology of seizures. Molecules derived from 1,3,4-oxadiazole have been found to exhibit diverse biological activities, including anticonvulsant effect. In this work, we study the activity of the compound 2-[(4-methoxyphenylselenyl)methylthio]-5-phenyl-1,3,4-oxadiazole (MPMT-OX) in the GABAergic and cholinergic systems. We demonstrate that MPMT-OX reduced the locomotor activity of C. elegans with a normal balance between the E/I systems and increased the resistance to paralysis in worms exposed to pentylenetetrazol and aldicarb. MPMT-OX increased seizure resistance and assisted in the recovery of locomotor activity in worms with deletions in the genes unc-46, which regulates the transport of GABA into vesicles, and unc-49, which encodes the GABA receptor. C. elegans with deletions in the unc-25 and unc-47 genes did not respond to treatment. Therefore, we suggest that the compound MPMT-OX upregulates GABAergic signaling in a manner dependent on the unc-25 gene, which is responsible for GABA synthesis, and unc-47, which encodes the vesicular GABA transporter.
Topics: Animals; Behavior, Animal; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Electrophysiological Phenomena; GABA Agonists; Locomotion; Oxadiazoles; Parasympathetic Nervous System; Seizures; Synaptic Transmission; Synaptic Vesicles; gamma-Aminobutyric Acid
PubMed: 31415799
DOI: 10.1016/j.neuro.2019.08.001 -
Frontiers in Immunology 2019Farming and pesticide use have been associated with systemic autoimmune diseases, and while certain organochlorine insecticides and other pesticides are suspected to...
Farming and pesticide use have been associated with systemic autoimmune diseases, and while certain organochlorine insecticides and other pesticides are suspected to influence risk, the role of specific pesticides in the development of systemic autoimmunity is not known. We measured serum antinuclear autoantibodies (ANA) by immunofluorescence on Hep-2 cells in 668 male farmers in the study of Biomarkers of Exposure and Effect in Agriculture (BEEA; 2010-2013), an Agricultural Health Study (AHS) subcohort. We examined ANA in relation to lifetime use of 46 pesticides first reported at AHS enrollment (1993-1997) and updated at intervals through BEEA enrollment. Odds ratios (OR) and 95% confidence intervals (CI) were estimated after adjusting for age, state, education, season of blood draw, current pesticide use, and correlated pesticides. Having ANA antibodies (3 or 4+ intensity at a 1:80 dilution, 21% of study participants) was associated with a reported history of seeking medical care due to exposure to pesticides (OR 2.15; 95%CI 1.17, 3.95), use of the fumigant methyl bromide (OR 3.16; 95%CI 1.05, 9.5), and use of petroleum oil/distillates (OR 1.50; 95%CI 1.00, 2.25). Using a higher threshold (3 or 4+ at a 1:160 dilution, 9%) ANA positivity was associated with the carbamate insecticide aldicarb (OR 4.82; 95%CI 1.33, 17.5) and greater combined use of four cyclodiene organochlorine insecticides (top tertile of intensity-weighted lifetime days vs. no use; OR 3.20; 95%CI 1.10, 9.27). By contrast, greater use of non-cyclodiene organochlorine insecticides was inversely associated with ANA (1:80 dilution 3 or 4+, OR 0.24; 95%CI 0.08, 0.72). Specific autoantibodies (to extractable nuclear antigens and anti-dsDNA), measured on those with ANA detected at the 1:80 dilution 3 or 4+, were seen in 15 individuals (2%), and were associated with use of two or more cyclodiene organochlorine insecticides and several other pesticides (e.g., carbofuran, ethylene dibromide). These findings suggest that specific pesticide exposures may have long-term effects on ANA prevalence and support the hypothesis that certain organochlorine insecticides may increase the risk of developing systemic autoimmunity.
Topics: Aged; Agriculture; Antibodies, Antinuclear; Autoimmunity; Farmers; Humans; Hydrocarbons, Chlorinated; Longitudinal Studies; Male; Middle Aged; Occupational Exposure; Pesticides; Prevalence; Risk Factors; Surveys and Questionnaires
PubMed: 31354699
DOI: 10.3389/fimmu.2019.01476 -
Journal of Environmental Science and... 2019The characterization of soluble cholinesterases (ChEs) together with carboxylesterases (CEs) in as suitable biomarkers of neurotoxicity was the main aim of this study....
The characterization of soluble cholinesterases (ChEs) together with carboxylesterases (CEs) in as suitable biomarkers of neurotoxicity was the main aim of this study. ChEs of were characterized considering enzymatic activity, substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters ( and ) and response to model inhibitors (eserine hemisulfate, iso-OMPA, BW284C51), and carbamates (carbofuran, methomyl, aldicarb, and carbaryl). CEs were characterized based on enzymatic activity, kinetic parameters and response to carbamates (carbofuran, methomyl, aldicarb, and carbaryl). Results showed that cholinesterases from showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was not hydrolyzed differently from other Annelida species. CE activity was in the same range of cholinesterase activity with acetylthiocholine as substrate; the enzyme activity showed high affinity for the substrate p-nytrophenyl butyrate. Carbamates inhibited ChE activity with propionylthiocholine as substrate to a higher extent than with acetylthiocoline. Also CE activity was inhibited by all tested carbamates except carbaryl. data highlighted the presence of active forms of ChEs and CEs in that could potentially be inhibited by pesticides at environmentally relevant concentration.
Topics: Animals; Annelida; Biomarkers; Carbamates; Carbaryl; Carbofuran; Carboxylic Ester Hydrolases; Cholinesterase Inhibitors; Cholinesterases; Kinetics; Methomyl; Neurotoxins
PubMed: 31311415
DOI: 10.1080/03601234.2019.1640028 -
Molecular and Cellular Neurosciences Jul 2019miR-137 is a highly conserved microRNA (miRNA) that is associated with the control of brain function and the etiology of psychiatric disorders including schizophrenia...
miR-137 is a highly conserved microRNA (miRNA) that is associated with the control of brain function and the etiology of psychiatric disorders including schizophrenia and bipolar disorder. The Caenorhabditis elegans genome encodes a single miR-137 ortholog called mir-234, the function of which is unknown. Here we show that mir-234 is expressed in a subset of sensory, motor and interneurons in C. elegans. Using a mir-234 deletion strain, we systematically examined the development and function of these neurons in addition to global C. elegans behaviors. We were however unable to detect phenotypes associated with loss of mir-234, possibly due to genetic redundancy. To circumvent this issue, we overexpressed mir-234 in mir-234-expressing neurons to uncover possible phenotypes. We found that mir-234-overexpression endows resistance to the acetylcholinesterase inhibitor aldicarb, suggesting modification of neuromuscular junction (NMJ) function. Further analysis revealed that mir-234 controls neuropeptide levels, therefore positing a cause of NMJ dysfunction. Together, our data suggest that mir-234 functions to control the expression of target genes that are important for neuropeptide maturation and/or transport in C. elegans. SIGNIFICANCE STATEMENT: The miR-137 family of miRNAs is linked to the control of brain function in humans. Defective regulation of miR-137 is associated with psychiatric disorders that include schizophrenia and bipolar disorder. Previous studies have revealed that miR-137 is required for the development of dendrites and for controlling the release of fast-acting neurotransmitters. Here, we analyzed the function a miR-137 family member (called mir-234) in the nematode animal model using anatomical, behavioral, electrophysiological and neuropeptide analysis. We reveal for the first time that mir-234/miR-137 is required for the release of slow-acting neuropeptides, which may also be of relevance for controlling human brain function.
Topics: Animals; Caenorhabditis elegans; MicroRNAs; Movement; Neuromuscular Junction; Neurons; Synaptic Transmission
PubMed: 31200102
DOI: 10.1016/j.mcn.2019.06.001 -
Analytical and Bioanalytical Chemistry Jul 2019Herein, rare-earth europium doped in GdO@SiO-based molecularly imprinted polymer (MIP) composite nanospheres with a multilayer core-shell structure was successfully...
Herein, rare-earth europium doped in GdO@SiO-based molecularly imprinted polymer (MIP) composite nanospheres with a multilayer core-shell structure was successfully prepared via a facile and versatile layer-by-layer assembly strategy of combination with sol-gel, hydrothermal, and surface imprinting procedure. The rare-earth GdO:Eu was embedded into the inner portion of the imprinted polymer which was well-suited for fluorescent monitoring carbaryl selectively. Results showed that the recognition process of the nanosensor for carbaryl was fast and reached dynamic equilibrium at ca. 20 min. The fluorescence intensity (F/F) is linearly related to the concentration of carbaryl [Q] within the range of 16-80 μg mL, and the linear equation is F/F = 0.8909 - 9.775 × 10[Q] (R = 0.9963) with 10 μg mL as the detection limit. Competition experiments showed that other analogues (methomyl, aldicarb, and isoprocarb) have nearly no interference in the detection of carbaryl. Moreover, this MIP nanosensor was successfully applied to detect carbaryl in green tea samples without pretreatment. The study afforded an efficient and desirable fluorescence sensor for carbaryl detection in a complicated matrix, which hopefully will be used for biomedical/chemical sensing recognition. Graphical abstract.
Topics: Fluorescence; Gadolinium; Metal Nanoparticles; Silicon Dioxide; Tea
PubMed: 31143966
DOI: 10.1007/s00216-019-01902-2 -
Environmental Toxicology and... Jul 2019In 2008, 30 active substances from plant protection products were banned from marketing in France. Nevertheless, the French Poison Control Centers continue to see cases...
In 2008, 30 active substances from plant protection products were banned from marketing in France. Nevertheless, the French Poison Control Centers continue to see cases of poisoning caused by these active substances that are no longer approved. The aim of this study was to describe the characteristics of the reported cases in mainland France and in overseas French territories, over the period 2012-2016. A total of 408 cases of human exposure were reported during the study period. The most commonly reported substances were dichlorvos (24.8%, n = 108), paraquat (23.8%, n = 97), aldicarb (14.7%, n = 60), diuron (9.6%, n = 39), dinocap (5.1%, n = 21), methomyl (4.2%, n = 17), carbofuran (3.9%, n = 16), anthraquinone (2.9%, n = 12) and carbendazim (2.7%, n = 11). The number of cases of intoxication dropped sharply between 2012 (n = 119) and 2016 (n = 47), except in the overseas French territories. Among the 72 serious cases (severe or life-threatening or with a fatal outcome), the most common substances involved were paraquat (n = 34), aldicarb (n = 24) and carbofuran (n = 7). This study suggests persistent use of carbamate insecticides, the existence of illegal imports of dichlorvos or paraquat-based products, and the use of certain banned fungicides in the professional agricultural sector. Information and collection campaigns are therefore essential after the withdrawal of marketing authorization for the plant protection products.
Topics: Adolescent; Adult; Aged; Carbamates; Child; Child, Preschool; Dichlorvos; Environmental Exposure; Female; France; Humans; Infant; Infant, Newborn; Male; Middle Aged; Paraquat; Pesticides; Poison Control Centers; Young Adult
PubMed: 30953934
DOI: 10.1016/j.etap.2019.03.017