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1.
Pestic Biochem Physiol ; 183: 105057, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35430061

RESUMO

Fenoxaprop-P-ethyl (FE) is a highly effective weed control agent for rice fields, but it causes phytotoxicity in crops. A whole-plant bioassay has revealed that isoxadifen-ethyl hydrolysate (IH) can significantly improve the tolerance of rice to FE, but the molecular mechanisms underlying this phenomenon are still unclear. In this study, we performed RNA-Seq analysis using rice seedlings treated with FE and IH to determine the IH-regulated candidate genes involved in metabolic resistance to FE. We also analyzed spatiotemporal expression using quantitative reverse transcription polymerase chain reaction to reveal the expression patterns of these genes under different treatments. The results showed that genes encoding metabolic enzymes, such as cytochrome P450 monooxygenases, glutathione-s-transferases, UDP-glycosyltransferase, carboxylesterase, and ATP-binding cassette transporter, were influenced by the application of IH. Most of these genes were upregulated, and their products were involved in various stages of FE metabolism. Tolerance to FE was primarily mediated by CarE15, CYP86A1, GSTU6, GST4, UGT13248, UGT79, and ABCC4, all of which played a vital role in regulating the detoxification process of FE. Our findings elucidated the protective mechanisms of IH, which can help alleviate the phytotoxic effects of FE and expand its potential for application in agriculture.


Assuntos
Herbicidas , Oryza , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Perfilação da Expressão Gênica , Herbicidas/metabolismo , Herbicidas/toxicidade , Redes e Vias Metabólicas , Oryza/genética , Oryza/metabolismo , Transcriptoma
2.
Arch Microbiol ; 204(5): 252, 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35411478

RESUMO

A widely used herbicide for controlling weeds, glyphosate, is causing environmental pollution. It is necessary to remove it from environment using a cost-effective and eco-friendly method. The aims of this study were to isolate glyphosate-degrading bacteria and to optimize their degradative conditions required for bioremediation. Sixteen bacterial strains were isolated through enrichment and one strain, Rhodococcus soli G41, demonstrated a high removal rate of glyphosate than other strains. Response surface methodology was employed to optimize distinct environmental factors on glyphosate degradation of G41 strain. The optimal conditions for the maximum glyphosate degradation were found to have the NH4Cl concentration of 0.663% and glyphosate concentration of 0.115%, resulting in a maximum degradation of 42.7% after 7 days. Bioremediation analysis showed 47.1% and 40% of glyphosate in unsterile soil and sterile soil was removed by G41 strain after 14 days, respectively. The presence of soxB gene in G41 strain indicates that the glyphosate is degraded via the eco-friendly sarcosine pathway. The results indicated that G41 strain has the potential to serve as an in-situ candidate for bioremediation of glyphosate polluted environments.


Assuntos
Herbicidas , Rhodococcus , Biodegradação Ambiental , Glicina/análogos & derivados , Herbicidas/metabolismo , Rhodococcus/genética , Rhodococcus/metabolismo , Solo , Microbiologia do Solo
3.
Genes (Basel) ; 13(3)2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35328069

RESUMO

Echinochloa colona and other species in this genus are a threat to global rice production and food security. Quinclorac, an auxin mimic, is a common herbicide for grass weed control in rice, and Echinochloa spp. have evolved resistance to it. The complete mode of quinclorac action and subsequent evolution of resistance is not fully understood. We analyzed the de novo transcriptome of multiple-herbicide-resistant (ECO-R) and herbicide-susceptible genotypes in response to quinclorac. Several biological processes were constitutively upregulated in ECO-R, including carbon metabolism, photosynthesis, and ureide metabolism, indicating improved metabolic efficiency. The transcriptional change in ECO-R following quinclorac treatment indicates an efficient response, with upregulation of trehalose biosynthesis, which is also known for abiotic stress mitigation. Detoxification-related genes were induced in ECO-R, mainly the UDP-glycosyltransferase (UGT) family, most likely enhancing quinclorac metabolism. The transcriptome data also revealed that many antioxidant defense elements were uniquely elevated in ECO-R to protect against the auxin-mediated oxidative stress. We propose that upon quinclorac treatment, ECO-R detoxifies quinclorac utilizing UGT genes, which modify quinclorac using the sufficient supply of UDP-glucose from the elevated trehalose pathway. Thus, we present the first report of upregulation of trehalose synthesis and its association with the herbicide detoxification pathway as an adaptive mechanism to herbicide stress in Echinochloa, resulting in high resistance.


Assuntos
Echinochloa , Herbicidas , Oryza , Echinochloa/genética , Echinochloa/metabolismo , Resistência a Herbicidas/genética , Herbicidas/metabolismo , Herbicidas/farmacologia , Ácidos Indolacéticos/metabolismo , Oryza/genética , Quinolinas , Transcriptoma , Trealose/metabolismo , Difosfato de Uridina/metabolismo , Xenobióticos/metabolismo
4.
J Hazard Mater ; 432: 128689, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35325860

RESUMO

Widespread use of the herbicide glyphosate in agriculture has resulted in serious environmental problems. Thus, environment-friendly technological solutions are urgently needed for the removal of residual glyphosate from soil. Here, we successfully isolated a novel bacterial strain, Chryseobacterium sp. Y16C, which efficiently degrades glyphosate and its main metabolite aminomethylphosphonic acid (AMPA). Strain Y16C was found to completely degrade glyphosate at 400 mg·L-1 concentration within four days. Kinetics analysis indicated that glyphosate biodegradation was concentration-dependent, with a maximum specific degradation rate, half-saturation constant, and inhibition constant of 0.91459 d-1, 15.79796 mg·L-1, and 290.28133 mg·L-1, respectively. AMPA was identified as the major degradation product of glyphosate degradation, suggesting that glyphosate was first degraded via cleavage of its C-N bond prior to subsequent metabolic degradation. Strain Y16C was also found to tolerate and degrade AMPA at concentrations up to 800 mg·L-1. Moreover, strain Y16C accelerated glyphosate degradation in soil indirectly by inducing a slight alteration in the diversity and composition of soil microbial community. Taken together, our results suggest that strain Y16C may be a potential microbial agent for bioremediation of glyphosate-contaminated soil.


Assuntos
Chryseobacterium , Herbicidas , Microbiota , Poluentes do Solo , Bactérias/metabolismo , Chryseobacterium/genética , Chryseobacterium/metabolismo , Glicina/análogos & derivados , Herbicidas/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/análise
5.
J Mol Model ; 28(4): 77, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35244782

RESUMO

Phalaris minor is a major weed of wheat crop which has evolved resistance against herbicides. Isoproturon is the most accepted herbicide developed resistance in 1992. Later, introduced herbicides also developed resistance and cross-resistance to their respective binding sites. Isoproturon binds at the QB binding site of the D1 protein of photosystem-II (PS-II), which blocks the electron transfer in photosynthesis. In this work, we have carried out a series of computational studies to prioritize the promising herbicides against D1 protein of P. minor. Through the computational studies, twenty-four lead molecules are prioritized which have shown a higher binding affinity and inhibition constant than the reference ligand molecule. The binding and conformational stability of docked complexes was evaluated by molecular dynamics simulations and binding free energy calculations i.e., MM/PBSA. A list of amino acids such as Ala225, Ser226, Phe227, and Asn229 present in the binding site of protein is obtained to be playing an important role in the stability of the protein-lead complex via hydrogen bond and π-π interactions. Binding free energy calculation revealed that the selected lead molecule binding is energetically favorable and driven by electrostatic interactions. Among 24 leads, computational results have uncovered eight promising compounds as potential herbicides which have shown comparable physiochemical profile, better docking scores, system stability, H-bond occupancy, and binding free energy than terbutryn, a reference molecule. These prioritized molecules were custom synthesized and evaluated for their herbicidal activity and specificity through whole plant assay under laboratory-controlled conditions. The lead molecule ELC5 (6-ethoxy-4-N-(2-morpholin-4-ylethyl)-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine) has shown comparable activity to the reference herbicide(isoproturon) against P. minor.


Assuntos
Herbicidas , Phalaris , Diaminas , Herbicidas/química , Herbicidas/metabolismo , Herbicidas/farmacologia , Phalaris/metabolismo , Triazinas/farmacologia , Triticum/metabolismo
6.
Aquat Toxicol ; 246: 106142, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35306440

RESUMO

Glyphosate is the most used herbicide worldwide, with no historical comparison. It is used for genetically modified crops, and particularly in Florida, it is used as a sugar cane ripener. An aquatic formulation (Rodeo®) is used to treat aquatic weeds in waterbodies and drainage canals. Because of its extended use, glyphosate can run off or be sprayed directly into waterbodies, and chronically expose aquatic wildlife. Exposure in animal models has been associated with kidney and liver damage and glyphosate has been suggested as an endocrine disruptor. We exposed adult male largemouth bass for 21 days to two doses of glyphosate and Rodeo® (chemically equivalent concentration of glyphosate) at 0.5 mg L-1 and 10 mg L-1 and to a clean water control (n=4 fish/tank in quadruplicate). Concentrations during the experiment were corroborated with UHPLC-MS/MS. Total RNA was isolated from the trunk kidney and head kidney. RNA-seq was performed for the high doses compared to controls. Transcripts were analyzed with fish and mammalian pathway analyses software. Transcripts mapped to Zebrafish metabolic pathways using PaintOmics showed steroid hormone biosynthesis in the trunk kidney as the most significantly enriched pathway. Steroid hormones were measured in plasma by UHPLC-MS/MS. Total androgens were significantly reduced at 0.5 mg L-1 of glyphosate and at equivalent concentrations in Rodeo® compared to controls. 11-ketotestosterone and estrone concentrations were significantly reduced in all doses. A gene involved in the conversion of testosterone to 11-ketotestosterone was down-regulated by glyphosate. Using the mammalian pathway analysis algorithm, cellular processes associated with T-cell activation/development and intracellular pH were significantly enriched in the trunk kidney by glyphosate and Rodeo® exposure. Endocrine disruption was corroborated at the hormone and gene expression levels. Rodeo® and glyphosate share gene expression pathways, however, Rodeo® had more pronounced effects in largemouth bass.


Assuntos
Bass , Herbicidas , Poluentes Químicos da Água , Animais , Bass/metabolismo , Produtos Agrícolas/genética , Glicina/análogos & derivados , Herbicidas/metabolismo , Herbicidas/toxicidade , Hormônios/metabolismo , Masculino , Mamíferos/genética , Plantas Geneticamente Modificadas , Esteroides/metabolismo , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética
7.
Bioresour Technol ; 351: 126997, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35292382

RESUMO

This study demonstrates the stereoselective degradation patterns and biodegradation mechanisms of metolachlor (MET) and napropamide (NAP) in integrated vertical flow constructed wetlands (IVCW). The higher interphase transferability of NAP resulted in higher degradation rates of 90.60 ± 4.09%. The enantiomeric fraction (EF) values of 0.38 ± 0.02 and 0.54 ± 0.03, respectively, recorded for the enantiomers S-MET and R-NAP, with higher herbicidal activities, demonstrated their highly selective biodegradation patterns. The antioxidant enzyme activities and fluorescence parameters of plants showed positive correlations with the degradation efficiency and enantioselectivity of MET and NAP. Adaptive regulations by plants promoted the proliferation of microbial genera like Enterobacter and unclassified_Burkholderiales, which could facilitate plant growth. Moreover, enrichment of the herbicide-degrading functional bacteria Terrimonas (5.10%), Comamonas (4.05%) Pseudoxanthomonas (4.49%) and Mycobacterium (1.42%) demonstrably promoted the preferential degradation of S-MET and R-NAP. Furthermore, the abundance of Ferruginibacter favored the use of R-NAP as carbon source to achieve co-removal of R-NAP and NO3--N.


Assuntos
Herbicidas , Áreas Alagadas , Amidas , Bactérias/metabolismo , Biodegradação Ambiental , Herbicidas/metabolismo , Plantas/metabolismo
8.
Environ Pollut ; 302: 119079, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35245623

RESUMO

The excessive proliferation of Microcystis aeruginosa can lead to ecological damage, economic losses, and threaten animal and human health. For controlling Microcystis blooms, microorganism-based methods have attracted much attention from researchers because of their eco-friendliness and species-specificity. Herein, we first found that a Paucibacter strain exhibits algicidal activity against M. aeruginosa and microcystin degradation capability. The algicidal activity of DH15 (2.1 × 104 CFU/ml) against M. aeruginosa (2 × 106 cells/ml) was 94.9% within 36 h of exposure. DH15 also degraded microcystin (1.6 mg/L) up to 62.5% after 72 h. We demonstrated that the algicidal activity of DH15 against M. aeruginosa can be mediated by physical attachment and indirect attack: (1) Both washed cells and cell-free supernatant could kill M. aeruginosa efficiently; (2) Treatment with DH15 cell-free supernatants caused oxidative stress, altered the fatty acid profile, and damaged photosynthetic system, carbohydrate, and protein metabolism in M. aeruginosa. The combination of direct and indirect attacks supported that strain DH15 exerts high algicidal activity against M. aeruginosa. The expression of most key genes responsible for photosynthesis, antioxidant activity, microcystin synthesis, and other metabolic pathways in M. aeruginosa was downregulated. Strain DH15, with its microcystin degradation capacity, can overcome the trade-off between controlling Microcystis blooms and increasing microcystin concentration. Our findings suggest that strain DH15 possesses great potential to control outbreaks of Microcystis blooms.


Assuntos
Agentes de Controle Biológico , Burkholderiales , Microcystis , Agentes de Controle Biológico/metabolismo , Agentes de Controle Biológico/farmacologia , Burkholderiales/metabolismo , Herbicidas/metabolismo , Microcistinas/metabolismo , Microcystis/metabolismo , Fotossíntese
9.
Sci Total Environ ; 828: 154414, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35278537

RESUMO

Pendimethalin (PND) is a dinitroaniline preemergent herbicide widely used to control grasses and weeds. The present study aimed to evaluate the PND potential effects on the development of zebrafish early-life stages. The research focuses first on acute toxicity, followed by the integration of toxicity results through histopathology, oxidative status, and neurotoxicity evaluation of sublethal and environmentally relevant concentrations. Zebrafish larvae exposed to PND showed mortality and developed sublethal alterations including impaired fin development, lordosis, scoliosis, blood congestion, impaired blood flow, and reduced heartbeat. PND exposure (0.5 mg/L) affects musculoskeletal development leading to delayed and reduced ossification of the vertebral centra in the developing vertebral column and disruption of muscle morphology. Herbicide exposure (0.5 mg/L and 0.05 mg/L) led also to biochemical changes of antioxidant enzymes, increasing the activity of CAT, GR, and GPx, while no effects were observed on the activity of SOD and GST in zebrafish larvae. Lastly, AChE activity, a biochemical marker of neurotoxicity, was also increased in zebrafish larvae exposed to 0.5 mg/L of PND. These results confirm the developmental toxicity of PND in zebrafish early-life stages, pointing out the potential role of oxidative stress in the onset of sublethal alterations.


Assuntos
Herbicidas , Poluentes Químicos da Água , Compostos de Anilina/toxicidade , Animais , Embrião não Mamífero , Herbicidas/metabolismo , Larva , Estresse Oxidativo , Poluentes Químicos da Água/metabolismo , Peixe-Zebra/fisiologia
10.
Toxicol In Vitro ; 81: 105333, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35182771

RESUMO

Most OECD guidelines for chemical risk assessment include tests performed on animals, raising financial, ethical and scientific concerns. Thus, the development of human-based models for toxicity testing is highly encouraged. Here, we propose an in vitro multi-organ strategy to assess the toxicity of chemicals. Human induced pluripotent stem cells (hiPSCs)-derived models of the brain, blood-brain barrier, kidney, liver and vasculature were generated and exposed to paraquat (PQ), a widely employed herbicide with known toxic effects in kidneys and brain. The models showed differential cytotoxic sensitivity to PQ after acute exposure. TempO-Seq analysis with a set of 3565 probes revealed the deregulation of oxidative stress, unfolded protein response and estrogen receptor-mediated signaling pathways, in line with the existing knowledge on PQ mechanisms of action. The main advantages of this strategy are to assess chemical toxicity on multiple tissues/organs in parallel, exclusively in human cells, eliminating the interspecies bias, allowing a better evaluation of the differential sensitivity of the models representing the diverse organs, and increasing the chance to identify toxic compounds. Furthermore, although we focused on the mechanisms of action of PQ shared by the different models, this strategy would also allow for organ-specific toxicity testing, by including more cell type-specific probes for TempO-Seq analyses. In conclusion, we believe this strategy will participate in the further improvement of chemical risk assessment for human health.


Assuntos
Herbicidas , Células-Tronco Pluripotentes Induzidas , Animais , Herbicidas/metabolismo , Herbicidas/toxicidade , Humanos , Fígado/metabolismo , Estresse Oxidativo , Paraquat/toxicidade
11.
Sci Total Environ ; 823: 153791, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35150682

RESUMO

Glufosinate-ammonium, a widely used chiral herbicide, has become the focus of attention because of its toxicity toward non-target organisms and its degradation behavior in the environment. With the introduction of L-glufosinate-ammonium products, the toxicity and environmental behavior of rac-glufosinate-ammonium and L-glufosinate-ammonium have become the subject of increasing interest. The overall goal of this study was to investigate the differences in toxicity and biodegradation of rac-glufosinate-ammonium and L-glufosinate-ammonium in an aquatic organism, Scenedesmus obliquus. The toxicity of rac-glufosinate-ammonium and L-glufosinate-ammonium to S. obliquus was compared by measuring EC50, malondialdehyde (MDA) content, protein content and antioxidant enzyme activity. The 96-h EC50 values of rac-glufosinate-ammonium and L-glufosinate-ammonium were 57.22 µg/mL and 25.55 µg/mL, respectively, which indicated that L-glufosinate-ammonium was more toxic to S. obliquus than rac-glufosinate-ammonium. Based on the MDA content, protein content, and antioxidant enzyme (SOD and CAT) activity, we found that L-glufosinate-ammonium could cause more serious oxidative damage than rac-glufosinate-ammonium. The residual amount of glufosinate-ammonium and its metabolites in the culture medium and S. obliquus were determined by HPLC-HRMS. Comparison of glufosinate-ammonium concentrations in algae-free and algae-containing media, showed that glufosinate-ammonium degradation in the S. obliquus system was significantly increased, and the degradation rate of L-glufosinate-ammonium was faster than that of D-glufosinate-ammonium. No enantiomerization was observed for pure L-glufosinate-ammonium treatment. N-acetyl-glufosinate was identified as the main metabolite of glufosinate-ammonium.


Assuntos
Herbicidas , Scenedesmus , Aminobutiratos/toxicidade , Herbicidas/metabolismo , Herbicidas/toxicidade , Scenedesmus/metabolismo , Estereoisomerismo
12.
Toxicol Appl Pharmacol ; 439: 115912, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35143805

RESUMO

Human internal dosimetry of pesticides is essential in the risk assessment when toxicity has been confirmed in laboratory animals. While human toxicokinetics data of pesticides are hardly obtained intendedly, the use of physiologically based pharmacokinetic (PBPK) modeling has become important for predicting human internal dosimetry. Especially, when the compound exhibits complicated pharmacokinetics via active uptake, metabolism, and biliary excretion in liver, it is difficult to obtain these hepatic parameters only by the in vitro experiments. Epyrifenacil, a new herbicide, is rapidly metabolized to S-3100-CA (CA) in mammals and causes hepatotoxicity in mice. CA is eliminated from the systemic circulation by biliary excretion and metabolism in liver. Although uptake of CA by transporters is observed in mouse primary hepatocytes, significantly less of it is observed in human primary hepatocytes. In order to evaluate human internal dosimetry of CA, a precise PBPK model was developed. To obtain human hepatic parameters, i.e., hepatic elimination intrinsic clearance via biliary excretion and metabolism, we used chimeric mice with humanized liver as a model to reproduce the complicated pharmacokinetics of CA in humans. After we developed a mouse PBPK model, by replacing mouse parameters with those of humans, we calculated CA concentration in human liver. Comparing the predicted CA exposure in human liver with the measured values in mice, we demonstrated a clear interspecies difference of approximately 4 times lower Cmax and AUC in humans. This result suggested that the risk of hepatotoxicity is less in humans than in mice.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Herbicidas , Animais , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Hepatócitos/metabolismo , Herbicidas/metabolismo , Herbicidas/toxicidade , Humanos , Cinética , Fígado/metabolismo , Mamíferos , Camundongos , Modelos Biológicos , Farmacocinética
13.
Ying Yong Sheng Tai Xue Bao ; 33(1): 229-238, 2022 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-35224945

RESUMO

In this study, triazine-degrading strain SB5 was isolated and screened from the activated sludge contaminated with atrazine by enrichment culture technology. Based on its morphology and 16S rRNA gene analysis, strain SB5 was initially identified as Paenarthrobacter sp. It contained the atrazine-degrading genes trzN, atzB, and atzC. The addition of glucose, sucrose, sodium citrate, yeast extract and peptone to the culture medium significantly increased the biomass and atrazine degradation efficiency of strain SB5. The addition of (NH4)2SO4 and NH4Cl inhibited the biomass of strain SB5, but did not affect its degradation efficiency for atrazine. The addition of starch did not affect the biomass of strain SB5, but significantly inhibited its degradation for atrazine. Strain SB5 showed good atrazine tolerance and atrazine degradation ability in the temperature range of 4-42 ℃, initial pH of 4-10 and initial concentration of 50-1000 mg·L-1. Using 100 mg·L-1 atrazine as the sole carbon source, the strain SB5 degraded 100% of atrazine within 36 h under the optimal conditions of 37 ℃ and initial pH 8.0. The results of degradation spectrum analysis showed that strain SB5 had a good degradation effect on the six triazine herbicides (simazine, terbuthylazine, propazine, cyanazine, ametryn and prometryn) at an initial concentration of 100 mg·L-1, and the degradation rates were 86.4%, 92%, 98.6%, 95.6%, 100% and 99.2% after 48 h of incubation, respectively. The results demonstrated that SB5 was an efficient and broad-spectrum degradation strain. The strain SB5 further enriched the strain resources for atrazine biodegradation, and its high-efficient and broad-spectrum degradation characteristics for triazine herbicides showed a potential application value in the development of bioremediation technology for the pollution of triazine herbicides.


Assuntos
Atrazina , Herbicidas , Atrazina/análise , Atrazina/metabolismo , Biodegradação Ambiental , Herbicidas/análise , Herbicidas/metabolismo , RNA Ribossômico 16S , Microbiologia do Solo
14.
Ecotoxicol Environ Saf ; 232: 113277, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35123186

RESUMO

The widespread use of agrochemicals for controlling pests and diseases of crops is recognized as a main threat to biodiversity. Sulfonylurea herbicides are being increasingly used and display low levels of degradation in water which suggest that they might affect non-target organisms. In a common garden experiment, eggs of a widespread amphibian (Bufo spinosus) were exposed to sublethal environmentally relevant concentrations of a widely used sulfonylurea herbicide, nicosulfuron, during the whole embryonic development. We assessed development-related traits (i.e., development duration, hatching success, hatchling size and occurrence of malformation) as well as antioxidant markers in response to contamination (i.e., SOD, GPx, catalase, thiols and relevant ratios thereof). We found that sublethal concentrations of nicosulfuron increased embryonic development duration, increased hatchling size and tended to increase malformations. Embryos exposed to nicosulfuron displayed decreased thiols and increased catalase activity suggesting alteration of oxidative status. We did not find any effect of nicosulfuron on SOD and GPx levels. Interestingly, higher catalase activity was linked to higher proportion of malformed individuals, suggesting that exposure to nicosulfuron induced teratogenic effects. Our results suggest that alteration of antioxidant levels might be one physiological mechanism through which nicosulfuron might cause detrimental effects on amphibian embryos. Sublethal effects of pesticides at environmentally relevant concentrations have been overlooked and require further investigations, especially in non-target taxa occurring in agricultural landscapes.


Assuntos
Herbicidas , Anfíbios/metabolismo , Animais , Desenvolvimento Embrionário , Herbicidas/metabolismo , Herbicidas/toxicidade , Humanos , Estresse Oxidativo , Piridinas , Compostos de Sulfonilureia/metabolismo , Compostos de Sulfonilureia/toxicidade
15.
Artigo em Inglês | MEDLINE | ID: mdl-35162387

RESUMO

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-ß-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.


Assuntos
Herbicidas , Ochrobactrum , Poluentes do Solo , Biodegradação Ambiental , Diurona/análise , Diurona/metabolismo , Estudos de Viabilidade , Herbicidas/metabolismo , Herbicidas/toxicidade , Ochrobactrum/metabolismo , Solo , Microbiologia do Solo , Poluentes do Solo/análise
16.
Environ Sci Pollut Res Int ; 29(24): 36684-36698, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35064489

RESUMO

Among the non-target microorganisms residing in crop fields that are potentially vulnerable to herbicides are cyanobacteria. They contribute to the maintenance of soil quality and fertility and hence are considered to be an important component of soil microflora. Consequently, the present study was aimed to check the influence of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) on some major parameters of carbon (CO2) and nitrogen (N2) fixations of a cyanobacterium Nostoc muscorum Meg 1 isolated from a rice field in Cherrapunji, Meghalaya, India. These include various photosynthetic pigments, the oxygen-evolving complex activity of the PSII, the protein contents of RuBisCO, D1 protein, isocitrate dehydrogenase (IDH), nitrogenase and glutamine synthetase (GS) enzymes, the heterocyst percentage, nitrogenase and GS enzyme activities, and production of total proteins and carbohydrates in the cyanobacterium in a varying range of 50 to 125 ppm doses of 2,4-D. The mRNA levels of several proteins were also analyzed. Besides carotenoid concentration that enhanced at 50 ppm, all other parameters were compromised by 2,4-D in a dose-dependent manner resulting in a reduction in photosynthetic and N2-fixing activities. The negative effect on N2-fixation was partly due to compromised IDH activity. RT-PCR analysis further showed that these negative effects were initiated at transcription levels as mRNA contents of all enzymes studied were found compromised under 2,4-D exposure. The scanning and transmission electron microscopy further revealed herbicide induced adverse changes in the morphology and ultrastructure of the organism. The significance of the work lies in its detailed analysis of the effect of 2,4-D at biochemical, physiological, and molecular levels.


Assuntos
Cianobactérias , Herbicidas , Nostoc muscorum , Ácido 2,4-Diclorofenoxiacético/metabolismo , Ácido 2,4-Diclorofenoxiacético/toxicidade , Cianobactérias/metabolismo , Herbicidas/metabolismo , Fixação de Nitrogênio , Nitrogenase/metabolismo , Nostoc muscorum/metabolismo , Fotossíntese , RNA Mensageiro/metabolismo , Solo
17.
Chem Res Toxicol ; 35(2): 315-325, 2022 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-34990119

RESUMO

Toxicokinetics (TK) of ionic compounds in the toxico-/pharmacological model zebrafish embryo (Danio rerio) depend on absorption, distribution, metabolism, and elimination (ADME) processes. Previous research indicated involvement of transport proteins in the TK of the anionic pesticide bromoxynil in zebrafish embryos. We here explored the interaction of bromoxynil with the organic anion-transporting polypeptide zebrafish Oatp1d1. Mass spectrometry imaging revealed accumulation of bromoxynil in the gastrointestinal tract of zebrafish embryos, a tissue known to express Oatp1d1. In contrast to the Oatp1d1 reference substrate bromosulfophthalein (BSP), which is actively taken up by transfected HEK293 cells overexpressing zebrafish Oatp1d1, those cells accumulated less bromoxynil than empty vector-transfected control cells. This indicates cellular efflux of bromoxynil by Oatp1d1. This was also seen for diclofenac but not for carbamazepine, examined for comparison. Correspondingly, internal concentrations of bromoxynil and diclofenac in the zebrafish embryo were increased when coexposed with BSP, inhibiting the activities of various transporter proteins, including Oatp1d1. The effect of BSP on accumulation of bromoxynil and diclofenac was enhanced in further advanced embryo stages, indicating increased efflux activity in those stages. An action of Oatp1d1 as an efflux transporter of ionic environmental compounds in zebrafish embryos should be considered in future TK assessments.


Assuntos
Herbicidas/metabolismo , Nitrilas/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Animais , Células HEK293 , Humanos , Estrutura Molecular , Nitrilas/química , Transportadores de Ânions Orgânicos/genética , Peixe-Zebra/embriologia , Proteínas de Peixe-Zebra/genética
18.
Microbiol Spectr ; 10(1): e0093421, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35019679

RESUMO

Phaeocystis globosa causes severe marine pollution by forming harmful algal blooms and releasing hemolytic toxins and is therefore harmful to marine ecosystems and aquaculture industries. In this study, Microbulbifer sp. YX04 exerted high algicidal activity against P. globosa by producing and secreting metabolites. The algicidal activity of the YX04 supernatant was stable after exposure to different temperatures (-80 to 100°C) and pH values (4 to 12) for 2 h, suggesting that algicidal substances could temporarily be stored under these temperature and pH value conditions. To explore the algicidal process and mechanism, morphological and structural changes, oxidative stress, photosynthesis, autophagic flux, and global gene expression were investigated. Biochemical analyses showed that the YX04 supernatant induced reactive oxygen species (ROS) overproduction, which caused lipid peroxidation and malondialdehyde (MDA) accumulation in P. globosa. Transmission electron microscopy (TEM) observation and the significant decrease in both maximum photochemical quantum yield (Fv/Fm) and relative electron transfer rate (rETR) indicated damage to thylakoid membranes and destruction of photosynthetic system function. Immunofluorescence, immunoblot, and TEM analyses indicated that cellular damage caused autophagosome formation and triggered large-scale autophagic flux in P. globosa. Transcriptome analysis revealed many P. globosa genes that were differentially expressed in response to YX04 stress, most of which were involved in photosynthesis, respiration, cytoskeleton, microtubule, and autophagosome formation and fusion processes, which may trigger autophagic cell death. In addition to P. globosa, the YX04 supernatant showed high algicidal activity against Thalassiosira pseudonana, Thalassiosira weissflogii, Skeletonema costatum, Heterosigma akashiwo, and Prorocentrum donghaiense. This study highlights multiple mechanisms underlying YX04 supernatant toxicity toward P. globosa and its potential for controlling the occurrence of harmful algal blooms. IMPORTANCE P. globosa is one of the most notorious harmful algal bloom (HAB)-causing species, which can secrete hemolytic toxins, frequently cause serious ecological pollution, and pose a health hazard to animals and humans. Hence, screening for bacteria with high algicidal activity against P. globosa and studies on the algicidal characteristics and mechanism will contribute to providing an ecofriendly microorganism-controlling agent for preventing the occurrence of algal blooms and reducing the harm of algal blooms to the environment. Our study first reported the algicidal characteristic and mechanism of Microbulbifer sp. YX04 against P. globosa and demonstrated that P. globosa shows different response mechanisms, including movement ability, antioxidative systems, photosynthetic systems, gene expression, and cell death mode, to adapt to the adverse environment when algicidal compounds are present.


Assuntos
Morte Celular Autofágica , Gammaproteobacteria/química , Haptófitas/citologia , Haptófitas/efeitos dos fármacos , Herbicidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Gammaproteobacteria/metabolismo , Haptófitas/crescimento & desenvolvimento , Haptófitas/metabolismo , Proliferação Nociva de Algas , Herbicidas/química , Herbicidas/metabolismo , Herbicidas/farmacologia , Concentração de Íons de Hidrogênio , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio
19.
Angew Chem Int Ed Engl ; 61(4): e202114022, 2022 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-34852184

RESUMO

Microbial secondary metabolite discovery is often conducted in pure monocultures. In a natural setting, however, where metabolites are constantly exchanged, biosynthetic precursors are likely provided by symbionts or hosts. In the current work, we report eight novel and architecturally unusual secondary metabolites synthesized by the bacterial symbiont Phaeobacter inhibens from precursors that, in a native context, would be provided by their algal hosts. Three of these were produced at low titres and their structures were determined de novo using the emerging microcrystal electron diffraction method. Some of the new metabolites exhibited potent algaecidal activity suggesting that the bacterial symbiont can convert algal precursors, tryptophan and sinapic acid, into complex cytotoxins. Our results have important implications for the parasitic phase of algal-bacterial symbiotic interactions.


Assuntos
Herbicidas/química , Ressonância Magnética Nuclear Biomolecular , Rhodobacteraceae/química , Herbicidas/metabolismo , Microscopia Eletrônica de Transmissão , Estrutura Molecular , Rhodobacteraceae/metabolismo
20.
Environ Sci Pollut Res Int ; 29(17): 25263-25275, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34839461

RESUMO

Environmental health and food safety issues potentially caused by the dinitroaniline herbicide pendimethalin (PM) are a worldwide concern. The toxicity response of ginger and tissue accumulation effects of PM on ginger biomass were studied by utilizing PM (CK (clean water), PM1 (0.4%), PM2 (0.67%), PM3 (1.0%), and PM4 (1.67%)) in a dose-response study. It significantly reduced the biomass of ginger under PM4, which is attributed to root damage. The net photosynthetic rate of ginger under PM4 was 11.37% lower than that of CK, which is mainly caused by stomatal limitation. In addition, the ultrastructure of chloroplasts has changed. PM4 caused the accumulation of reactive oxygen species (ROS) in ginger. The activity of superoxide dismutase (SOD) and peroxidase (POD) increased accordingly, maintaining the dynamic balance of ROS content. PM had no significant effect on the expression of ginger α-tubulin genes. PM was significantly accumulated in ginger roots, but not rhizomes. Si increased the productivity of ginger under PM4, which is mainly related to the increase of root development (root application of silicon) and photosynthetic efficiency (foliar application of silicon). Si reduced the ROS content due to the increase in SOD, POD, and catalase (CAT) activity and photosynthetic efficiency.


Assuntos
Gengibre , Herbicidas , Compostos de Anilina , Antioxidantes/metabolismo , Gengibre/química , Herbicidas/metabolismo , Oxirredutases/metabolismo , Peroxidase/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Silício/farmacologia , Superóxido Dismutase/metabolismo
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