Evaluating binding and interaction of selected pesticides with serum albumin proteins by Raman, 1H NMR, mass spectrometry and molecular dynamics simulation.

Addressing the acute pesticide poisoning and toxicity to humans, is a global challenge of top priority. Serum albumin is the most abundant plasma protein, capable of binding with herbicide and pesticide residues. This study reports multifaceted approaches for in-depth and robust investigation of the molecular interactions of selected pesticides, including propanil (PPL), bromoxynil (BXL), metolachlor (MLR) and glyphosate (GPE) with bovine serum albumin (BSA) proteins using experimental (Raman and FTIR spectroscopy, native mass spectrometry and high field 1H NMR), molecular dynamics (MD) simulation and principal component analysis (PCA). The binding of pesticides with BSA resulted in BSA amide I and amide II Raman spectral shifts. PCA of Raman spectra of serum-pesticide complexes showed the grouping of pesticides on the score plot based on the similarities and differences in pesticides' chemical structures. Native mass spectrometry results revealed strong adduct formation of the pesticides with the protein. The observed changes in chemical shifts, peak broadening or peak disappearance of characteristic proton signals of the pesticides, indicated altered chemical environments due to binding BSA-pesticides interactions. The results of MD simulation conducted for over 500 ns revealed strong pesticides interaction with LEU197, LEU218, LEU237, TRP213, SER286 and ILE289 residues to the site I of BSA. Free energy landscapes provided insights into the conformational changes in BSA on the binding of pesticides. Overall, the experimental and computational results are in consonant and indicate the binding of pesticides into the site I and site II (sub-domain IIA) of the BSA via hydrogen bonding, non-covalent and hydrophobic interactions.Communicated by Ramaswamy H. Sarma.

Intoxicación por Metahemoglobinizante, tipo Propanil

Las intoxicaciones por herbicidas propanil son frecuentes en las diferentes áreas agrícolas, sobre todo en los campos de cultivos de arroz. Se presenta el caso de un paciente agricultor, sin factores de riesgo, quien sufrió una intoxicación moderada por propanil. Pese a las limitaciones diagnósticas en cada centro hospitalario, la sospecha y los datos clínicos al ingreso pueden ser suficientes para la elaboración diagnóstica y su respectivo manejo.

Poisoning by propanil herbicides are common in different agricultural areas, especially in rice fields. We present the case of a farmer patient, without risk factors, who suffered a moderate intoxication by propanil. Despite the diagnostic limitations in each hospital, the suspicion and clinical data on admission may be sufficient for the diagnosis and its respective management.

Experimental and computational approaches to characterize a novel amidase that initiates the biodegradation of the herbicide propanil in Bosea sp. P5.

The herbicide propanil and its major metabolite 3,4-dichloroaniline (3,4-DCA) are difficult to biodegrade and pose great health and environmental risks. However, studies on the sole or synergistic mineralization of propanil by pure cultured strains are limited. A two-strain consortium (Comamonas sp. SWP-3 and Alicycliphilus sp. PH-34), obtained from a swep-mineralizing enrichment culture that can synergistically mineralize propanil, has been previously reported. Here, another propanil degradation strain, Bosea sp. P5, was successfully isolated from the same enrichment culture. A novel amidase, PsaA, responsible for initial propanil degradation, was identified from strain P5. PsaA shared low sequence identity (24.0-39.7 %) with other biochemically characterized amidases. PsaA exhibited optimal activity at 30 °C and pH 7.5 and had kcat and Km values of 5.7 s-1 and 125 µM, respectively. PsaA could convert the herbicide propanil to 3,4-DCA but exhibited no activity toward other herbicide structural analogs. This catalytic specificity was explained by using propanil and swep as substrates and then analyzed by molecular docking, molecular dynamics simulation and thermodynamic calculations, which revealed that Tyr138 is the key residue that affects the substrate spectrum of PsaA. This is the first propanil amidase with a narrow substrate spectrum identified, providing new insights into the catalytic mechanism of amidase in propanil hydrolysis.

Clinical characteristics, treatment and outcomes of acute propanil poisoning in a 7-year retrospective cohort study.

The present study was a 7-year retrospective cohort study (2012-2018) of patients treated for acute propanil poisoning by ingestion, using data from Ramathibodi Poison Center, Thailand. The aim of this study was to describe the clinical characteristics, treatment, outcomes and factors associated with moderate to severe outcomes and death following acute exposure to propanil. The effect of administering multiple-dose activated charcoal (MDAC) on clinical outcomes was also evaluated. A total of 275 cases were included. The results show that two thirds of patients were male and mean age was 40 years. Patients ingested either propanil or a mixture of propanil and other herbicides. The majority (98%) of exposures was intentional. Most patients (65.5%) presented with gastrointestinal symptoms. Methemoglobinemia and hemolysis were observed in 108 patients (39.3%) and 25 patients (9.1%), respectively. Median time to onset of methemoglobinemia and hemolysis after propanil ingestion was 5.5 and 48 h, respectively. One hundred and forty-one patients (51.3%) were treated with MDAC, and some patients received methylene blue (21.5%), intubation (18.5%), or blood transfusions (8%). All patients were admitted to hospitals. The median length of hospital stay of patients who survived was 3 days. Multivariate analysis indicated that neurological symptoms at presentation, methemoglobinemia and acute kidney injury during admission, were associated with moderate to severe outcomes. Factors associated with mortality were older age, larger amount of ingestion, neurological symptoms at presentation and hypotension during admission. The overall mortality rate was 6.2%. The mortality rate was 3.6% in patients that received MDAC and 9% in patients that did not, although the difference was not statistically significant. Subgroup analysis of patients who developed methemoglobinemia or both methemoglobinemia and hemolysis found a statistically significant lower mortality rate in patients that received MDAC. In conclusion, methemoglobinemia and hemolysis contribute to poor outcomes in acute propanil poisoning. Age, amount of ingestion, neurological symptoms at presentation and hypotension during admission could prognosticate deaths, and patients with these factors should be closely observed and aggressively managed.

A New Treatment Approach for Acute Propanil Poisoning: A Case Report.

Propanil is a widely used herbicide in agriculture and is also an important cause of poisoning in Sri Lanka. Incidence is around 2% and is commonly reported as self-poisoning. Although it is classified as an agent with low to medium toxicity, severe poisoning can cause lethal outcome and death especially when there is a limited medical facility. We describe a case of severe Propanil poisoning who was successfully treated in a peripheral hospital with available facilities.

Can Pesticides Dissolved in Runoff and Exposed to Maturing Rice (Oryza sativa) Plants be Transferred to Seeds?

Agriculture's global challenge to feed an estimated 7.7 billion people is further exacerbated by less available cropland for production and rapidly changing climate patterns. Pesticides are often utilized to minimize crop losses due to pest infestations; however, problems arise when these chemicals are transported off production acreage, either by storm or irrigation events, and into nearby water bodies. Innovative management practices are needed to not only reduce the volume of runoff, but also to mitigate various pollutants, such as pesticides, within the runoff. One such practice being evaluated involves using rice (Oryza sativa) as a pesticide mitigation tool. While rice plants may serve as a mechanism for phytoremediation, whether the seeds harvested from exposed plants could then be utilized as a human food source is an unanswered question. Thirty round mesocosms (55 L volume; 56 cm diameter; six replicates per treatment) were established with rice and exposed to aqueous concentrations of the pesticides clomazone, propanil, or cyfluthrin, as well as a mixture of the three pesticides. Six replicates with rice and no pesticide exposure served as controls. Initial pesticide exposure took place 8 weeks post-planting and continued once a week for 5 weeks. Rice plants, unmilled seeds, and mesocosm sediment were collected from each mesocosm 2 weeks after seed formation began and analyzed for pesticide concentrations using gas chromatography. Concentrations of pesticides in unmilled seed were below detection for individual exposures of clomazone, propanil, and cyfluthrin. When rice was exposed to the pesticide mixture, the mean ± SE unmilled seed cyfluthrin concentration was 14.8 ± 1.25 µg kg-1. These small-scale, preliminary studies offer insight into the possibility of using immature rice plants as a phytoremediation tool, while harvesting its grain after plant maturation for human consumption. Further research is needed to address this question on a larger scale and with multiple pesticide mixtures.

Analysis of serum levels of organochlorine pesticides and related factors in Parkinson's disease.

BACKGROUND: There is evidence that environmental factors contribute to the onset and progression of Parkinson's disease (PD). Pesticides are a class of environmental toxins that are linked to increased risk of developing PD. However, few studies have investigated the association between specific pesticides and PD, especially in China, which was one of the first countries to adopt the use of pesticides. METHODS: In this study, serum levels of 19 pesticides were measured in 90 patients with PD and 90 healthy spouse controls. We also analyzed the interaction between specific pesticides and PD. In addition, the association between pesticides and clinical features of PD was also investigated. Finally, we investigated the underlying mechanism of the association between pesticides and PD. RESULTS: Serum levels of organochlorine pesticides, which included α-hexachlorocyclohexane (HCH), ß-HCH, γ-HCH, δ-HCH, propanil, heptachlor, dieldrin, hexachlorobenzene, p,p'-dichlorodiphenyltrichloroethane and o,p'-dichloro-diphenyl-trichloroethane were higher in PD patients than controls. Moreover, α-HCH and propanil levels were associated with PD. Serum levels of dieldrin were associated with Hamilton Depression Scale and Montreal Cognitive Assessment scores in PD patients. In SH-SY5Y cells, α-HCH and propanil increased level of reactive oxygen species and decreased mitochondrial membrane potential. Furthermore, propanil, but not α-HCH, induced the aggregation of α-synuclein. CONCLUSIONS: This study revealed that elevated serum levels of α-HCH and propanil were associated with PD. Serum levels of dieldrin were associated with depression and cognitive function in PD patients. Moreover, propanil, but not α-HCH, induced the aggregation of α-synuclein. Further research is needed to fully elucidate the effects of pesticides on PD.

Pterocarpus mildbraedii leaf extract ebbs propanil-induced oxidative and apoptotic damage in the liver of rats.

Phytochemicals derived from plant sources are well recognized as sources of pharmacologically potent drugs in the treatment of several oxidative stress-related ailments. Dichloromethane/methanol (1:1) leaf extract of Pterocarpus mildbraedii was evaluated for its possible protection against oxidative stress and apoptosis in the liver of male Wistar rats exposed to propanil (PRP). In the experimental design, olive oil served as the vehicle, and rats were grouped into control (2 mL/kg olive oil), PRP (200 mg/kg/day), Pterocarpus mildbraedii extract (200 mg/kg/day), and Pterocarpus mildbraedii extract (200 mg/kg/day)+PRP (200 mg/kg/day), and treated daily, p.o., for seven days. Oxidative stress parameters, B-cell lymphoma 2 (Bcl-2), Bcl 2-associated X protein (Bax), p53, caspases (9/3), and terminal transferase dUTP nick end labeling (TUNEL) assays were observed in all groups. Propanil significantly elevated superoxide dismutase and lipid peroxidation levels, while concomitantly depleting GSH and p53 levels. Further, PRP enhanced the expressions of caspase-9, caspase-3, Bax, and TUNEL-positive cells in the liver of rats. However, these observed alterations were reversed following treatment with Pterocarpus mildbraedii extract. Our studies suggest that Pterocarpus mildbraedii extract protected against PRP toxicity by reducing oxidative stress and attenuating critical endpoints in the intrinsic apoptotic pathway.

Destino ambiental y efectos ecológicos de los tres herbicidas más utilizados en Colombia / Environmental fate and ecological effects of the three most commonly used herbicides in Colombia / Destino ambiental e efeitos ecológicos dos três herbicidas mais comumente usados na Colômbia

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Abstract Knowledge of the environmental and transport fate of pesticides is integral to characterizing environmental exposures. Agencies such as the Environmental Protection Agency (EPA) 27 integrate the characterization of an exposure with ecological effects to determine the risks of pesticide use. The three most widely used herbicides in Colombia are glyphosate, propanil, and glufosinate ammonium. Although glyphosate had, since the early 1970's, been considered an environmentally friendly herbicide, the weight of the evidence of studies beginning in the 1990s show that inadvertent applications in wetlands can be fatal to the larvae of amphibians. Although glyphosate formulations are typically considered moderately toxic (LC50 = 1-10 ppm) for most aquatic organisms, for many amphibian species they are highly toxic (LC50 ˂ 1 ppm). This concern is compounded by the fact that Colombia has an incredibly high diversity of amphibians (746 species). In addition, chronic exposures of some amphibian species to sublethal concentrations, which are more likely found in the environment, have been shown to cause decreased survival, intersex gonads, tail damage, prolongation of time to metamorphosis, and liver lipidosis. In Colombia, aerial applications of Glyphos-Cosmo-Flux have been used since 1997 to fumigate illicit coca crops. As of 2019, the International Union for Conservation of Nature (IUCN) Red List had 285 species of amphibians in Colombia considered threatened. We found that 132 of the endangered (EN) and critically endangered (CR) amphibian species were present in 11 of the 32 Colombian departments with illegal coca plantations. Therefore, studies are needed to evaluate the impact of the coca eradication program on the amphibian population of the country. Propanil is the main herbicide used in rice fields. Despite its rapid environmental degradation ((1 day in aerobic conditions), studies on the impact of propanil have found that at projected application rates (4.5 kg/ha), within 48 hours after application, it reduces dissolved oxygen to levels critically important for survival of fish. At very low concentrations of 50 ppb or less of propanil, this effect correlates with lower phytoplankton production rather than higher community respiration. Despite being mild to moderately toxic at acute exposures, chronic exposure data also show that concentrations greater than 9 ppb affect the growth, reproduction, and development of fish and invertebrates. With respect to glufosinate ammonium, although it is highly likely to contaminate surface (runoff) and groundwater due to its physicochemical properties, data suggest that it is practically non-toxic to aquatic and terrestrial species. The acute hazard ratios were well below the level of concern, and therefore the EPA determined that the acute risk to non-target terrestrial and aquatic organisms is very low.

Resumo O conhecimento do destino ambiental e de transporte dos pesticidas é parte integrante da caracterização das exposições ambientais. Agências como a Agência de Proteção Ambiental (EPA) 27 integram a caracterização de uma exposição com efeitos ecológicos para determinar os riscos do uso de pesticidas. Os três herbicidas mais usados na Colômbia são glifosato, propanil e glufosinato de amônio. Embora o glifosato tenha sido considerado um herbicida ambientalmente correto desde o início da década de 1970, foi evidenciado por estudos iniciados na década de 1990 que aplicações inadvertidas em pântanos podem ser fatais para larvas de anfíbios. Embora as formulações de glifosato sejam tipicamente consideradas moderadamente tóxicas (CL50 = 1-10 ppm) para a maioria dos organismos aquáticos, para muitas espécies de anfíbios elas são altamente tóxicas (CL50 ˂ 1 ppm). Essa preocupação é agravada pelo fato de que a Colômbia tem uma diversidade incrivelmente alta de anfíbios (791 espécies). Além disso, foi demonstrado que exposições crônicas de algumas espécies de anfíbios a concentrações subletais, que são mais prováveis no ambiente, causam diminuição da sobrevivência, gônadas intersex, dano na cauda, prolongamento do tempo até a metamorfose e lipidose hepática. Na Colômbia, aplicações aéreas de Glyphos-Cosmo-Flux têm sido usadas desde 1997 para fumigar plantações ilícitas de coca. Em 2019, a Lista Vermelha da União Internacional para a Conservação da Natureza (IUCN) tinha 285 espécies de anfíbios na Colômbia consideradas ameaçadas. Descobrimos que 132 das espécies de anfíbios em perigo (EN) e criticamente em perigo (CR) estavam presentes em 11 dos 32 departamentos colombianos onde há mais plantações ilegais de coca. Portanto, são necessários estudos para avaliar o impacto do programa de erradicação da coca na população de anfíbios do país. O propanil é o principal herbicida usado nos campos de arroz. Apesar de sua rápida degradação ambiental ((1 dia em condições aeróbicas), estudos sobre o impacto do propanil descobriram que nas taxas de aplicação projetadas (4,5 kg / ha), ele reduz o oxigênio dissolvido a níveis criticamente importantes para a sobrevivência dos peixes em 48 horas. após a aplicação. Este efeito se correlaciona com a produção de fitoplâncton mais baixa, em vez de maior respiração da comunidade em concentrações muito baixas de 50 ppb ou menos de propanil. Apesar de ser leve a moderadamente tóxico em exposições agudas, os dados de exposição crônica também mostram que concentrações maiores que 9 ppb afetam o crescimento, a reprodução e o desenvolvimento de peixes e invertebrados. Com relação ao glufosinato de amônio, embora tenha grande probabilidade de contaminar a superfície (escoamento) e as águas subterrâneas devido às suas propriedades físico-químicas, os dados sugerem que é praticamente atóxico para as espécies aquáticas e terrestres. As razões de risco agudo estavam bem abaixo do nível de preocupação e, portanto, a EPA determinou que o risco agudo para organismos terrestres e aquáticos não visados é muito baixo.

Evaluation of the occurrence and fate of pesticides in a typical Mediterranean delta ecosystem (Ebro River Delta) and risk assessment for aquatic organisms.

Delta ecosystems are areas of high ecologic and economic values, where wildlife commonly shares the territory with intensive agricultural activities, particularly, rice cultivation and seafood production. This work aimed at evaluating the occurrence of a wide spectrum of pesticides and transformation products in the water of irrigation and drainage channels of the Ebro River Delta (NE Spain) during the main rice-growing season, when pesticide application is at its peak. Furthermore, the impact that these contaminants may have on local ecosystems and seafood production activities was assessed. A total of 35 pesticides, mainly associated with rice cultivation, out of the 66 analyzed were detected. Bentazone, propanil, MCPA, acetamiprid, and triallate were found at the µg/L level. Cybutryne, despite being banned in the European Union, was measured for the first time in the area and at concentrations above its environmental quality standard (11-49 ng/L). Sixteen additional banned pesticides were also detected at trace levels, likely due to their desorption from soil and sediment particles. Despite its dilution when discharged into the bay, this study demonstrates that the agricultural use of pesticides may have important effects on water quality and may cause a serious hazard for aquatic non-target organisms, although other factors such as temperature and salinity may play also a relevant role. Bentazone, cybutryne, dicofol, imidacloprid, MCPA, and propanil may pose a moderate to high risk for aquatic organisms at the concentration levels measured during the rice-growing season. The co-occurrence of pesticides may result in a high risk for aquatic organisms in all sampling locations. The finding of the EU Watch List insecticides imidacloprid and acetamiprid at concentrations above their maximum acceptable method detection limit calls for control of their use and revision of their legal status.

Efficient activation of oxone by pyrite for the degradation of propanil: Kinetics and degradation pathway.

Pyrite (FeS2) is an abundant sulfide-associated iron mineral that exists in the earth. In this study, the pyrite/oxone process was demonstrated to be an effective approach for the catalytic degradation of propanil, where more than 90% decay ([propanil]0 = 0.01 mM) was achieved within 15 min. Typically, the effects of various experimental parameters, including catalyst loading, oxone dosage, propanil concentration, and initial solution pH, were examined. Two optimal reaction pH values were observed at pH 9.1 and pH 2.9. The generated SO4－ and OH were verified to be the dominant reactive radicals and primarily responsible for the propanil degradation. Both Fe(II) regeneration and sulfur conversion play an important role in oxone activation mechanism and effectively aid the catalytic activity of pyrite. Different co-existing natural water constituents exert dissimilar effects on the pyrite/oxone process. Additionally, the reusability test of pyrite exhibited a reasonable catalytic activity. The pyrite/oxone process was proven efficient in terms of propanil mineralization. A series of reaction intermediates was detected via four major degradation pathways. Overall, the pyrite/oxone process could be a promising approach for the removal of organic compounds in water.

Pterocarpus mildbraedii (Harms) extract resolves propanil-induced hepatic injury via repression of inflammatory stress responses in Wistar rats.

Pterocarpus mildbraedii (PME) is a green leafy vegetable from the Papilionaceae family. This study evaluated the anti-inflammatory activity of PME in Wistar rats exposed to experimental hepatotoxicity using propanil (PRP), a post-emergent herbicide. Animals were grouped as control, PRP, PME, and PME + PRP. After 7 days, the levels of stress-activated protein kinases/c-Jun N-terminal kinase (SAPK/JNK), p38 mitogen-activated protein kinase (p38 MAPK), and signal transducer and activator of transcription (STAT-3) were measured in rat liver. Furthermore, myeloperoxidase (MPO) and nitric oxide (NO) levels, as well as protein expressions of nuclear factor-κB (NF-κB p65), inducible nitric oxide synthase (iNOS), and cyclo-oxygenase-2 (COX-2) were determined. Compared with PRP-treated rats, PME significantly reduced the hepatic MPO and NO levels. PME also diminished NFκB, iNOS, and COX-2 protein expressions in PRP-treated rats. This study showed that Pterocarpus mildbraedii leaves produce active principles with relevant anti-inflammatory potential. PRACTICAL APPLICATIONS: Previous studies have shown that bioactive principles contained in medicinal plants can offer protection against chemically induced inflammation. Pterocarpus mildbraedii leaves, with rich content of polyphenols, flavonoids, and essential fatty acids, could be exploited as a therapeutic agent against pesticide-induced oxidative stress and inflammation. This current study has also shown that the potential of PME as a functional food is boosted by the presence of α-linolenic acid, an omega-3-fatty acid known to possess anti-inflammatory activity. Here, we elucidated the cellular mechanisms of the anti-inflammatory action of PME.

Novel lipophilic analogues from 2,4-D and Propanil herbicides: Biological activity and kinetic studies.

This work describes the synthesis of new lipophilic amides and esters analogues of classical organochlorides herbicides by incorporation of long-chains from fatty acids and derivatives. The new fatty esters and amides were synthesized in 96-99% and 80-89% yields, respectively. In general, all compounds tested showed superior in vitro activity than commercial herbicides against growth L. sativa and A. cepa, in ranges 86-100% of germinative inhibition. The target compounds showed, significantly more susceptible towards acid hydrolysis than 2,4-dichlorophenoxyacetic acid (2,4-D). The kinetic and NMR studies showed that the incorporation of lipophilic chains resulted in a decrease in half-life time of new herbicides compounds (1.5 h) than 2,4-D (3 h). These findings suggest the synthesis of new lipophilic herbicides as potential alternative to traditional formulations, by incorporation of long fatty alkyl chains in the molecular structure of 2,4-D, resulting in superior in vitro herbicidal activity, best degradation behavior and more hydrophobic derivatives.

Biodegradation of propanil by Acinetobacter baumannii DT in a biofilm-batch reactor and effects of butachlor on the degradation process.

The herbicide, propanil, has been extensively applied in weed control, which causes serious environmental pollution. Acinetobacter baumannii DT isolated from soil has been used to determine the degradation rates of propanil and 3,4-dichloroaniline by freely suspended and biofilm cells. The results showed that the bacterial isolate could utilize both compounds as sole carbon and nitrogen sources. Edwards's model could be fitted well to the degradation kinetics of propanil, with the maximum degradation of 0.027 ± 0.003 mM h-1. The investigation of the degradation pathway showed that A. baumannii DT transformed propanil to 3,4-dichloroaniline before being completely degraded via the ortho-cleavage pathway. In addition, A. baumannii DT showed high tolerance to butachlor, a herbicide usually mixed with propanil to enhance weed control. The presence of propanil and butachlor in the liquid media increased the cell surface hydrophobicity and biofilm formation. Moreover, the biofilm reactor showed increased degradation rates of propanil and butachlor and high tolerance of bacteria to these chemicals. The obtained results showed that A. baumannii DT has a high potential in the degradation of propanil.

Development and application of fluorescence sensor and test strip based on molecularly imprinted quantum dots for the selective and sensitive detection of propanil in fish and seawater samples.

Molecularly imprinted quantum dots (MIP-QDs) were successfully synthesized via reversed-phase microemulsion and used as the specific recognition element and signal probe of a fluorescence sensor or test strip to achieve the highly sensitive detection of propanil. The physical-chemical characteristics and excellent selectivity of MIP-QDs were elucidated. Under optimized parameters, the MIP-QDs had good linearity at the propanil concentration range of 1.0 µg/L to 20.0 × 103 µg/L by fluorescence quenching. The developed MIP-QD-based fluorescence sensor showed good recoveries ranging from 87.2 % to 112.2 %, and the relative standard deviation was below 6.0 % for the fish and seawater samples. In addition, the limits of detection (LODs) for fish and seawater were 0.42 µg/kg and 0.38 µg/L, respectively. The fluorescence test strip developed on the basis of the MIP-QDs also displayed satisfactory recoveries of 90.1 %-111.1 %, and the LOD for propanil in the seawater sample was 0.6 µg/L. The proposed fluorescence sensor and test strip were successfully used in propanil determination in environment and aquatic products.

Spirosoma sordidisoli sp. nov., a propanil-degrading bacterium isolated from a herbicide-contaminated soil.

A novel Gram-stain negative, aerobic, rod-shaped, asporogenous, propanil-degrading bacterial strain, TY50T, was isolated from a herbicide-contaminated soil in Nanjing, China. Strain TY50T was found to grow optimally at pH 9.0, 30 °C and in the absence of NaCl. The G + C content of the total DNA was determined to be 55.5 mol%. The 16S rRNA gene sequence of strain TY50T shows high identity to that of Spirosoma lacussanchae CPCC 100624T (99.3%), Spirosoma metallicum PR1014kT (94.8%) and Spirosoma soli MIMBbqt12T (94.6%). DNA-DNA hybridization indicated that the isolate had relatively low levels of DNA-DNA relatedness with S. lacussanchae CPCC 100624T (48.3%). Average nucleotide identity and the digital DNA-DNA hybridizations for draft genomes between strain TY50T and S. lacussanchae CPCC 100624T were 93.2% and 51.0%, respectively. The major cellular fatty acids of strain TY50T were identified as C16:1ω5c (24.5%) and summed feature 3 (C16:1ω6c/C16:1ω7c, 40.7%). MK-7 was found to be the predominant respiratory quinone. The major polar lipid profile includes phosphatidylethanolamine, an unidentified lipid and an unidentified aminolipid. These chemotaxonomic data support the affiliation of strain TY50T with the members of the genus Spirosoma. Strain TY50T can be distinguished from its close phylogenetic neighbours based on its phenotypic, genotypic, and chemotaxonomic features. Therefore, strain TY50T represents a novel member of the genus Spirosoma, for which the name Spirosoma sordidisoli sp. nov. is proposed. The type strain is TY50T (= KCTC 62494T = CCTCC AB 2018041T).

Characterization of an arylamidase from a newly isolated propanil-transforming strain of Ochrobactrum sp. PP-2.

Propanil, one of the most extensively used post-emergent contact herbicides, has also been reported to have adverse effect on environmental safety. A bacterial strain of Ochrobactrum sp. PP-2, which was capable of transforming propanil, was isolated from a propanil-contaminated soil collected from a chemical factory. An arylamidase gene mah responsible for transforming propanil to 3,4-dichloroaniline (3,4-DCA) was cloned from strain PP-2 by shotgun method and subsequently confirmed by function expression. The arylamidase Mah shares low amino acid sequence identity (27-50%) with other biochemically characterized amidases and shows less than 30% identities to other reported propanil hydrolytic enzymes. Mah was most active at pH 8 and 35 °C. Mah had a remarkable activity toward propanil (Km = 6.3 ±â€¯1.2 µM), showing the highest affinity efficiency for propanil as compared with other reported propanil hydrolytic enzymes. Our study also provides a new arylamidase for the hydrolysis of propanil.

Simulation-based assessment of the impact of fertiliser and herbicide application on freshwater ecosystems at the Three Gorges Reservoir in China.

Dams have profound impacts on river ecosystems, amongst them inundation of land, altered dynamics of the water body or uprising reservoir backwaters influencing tributary or upstream river sections. Along the outstandingly ecologically important Yangtze River in China, the Three Gorges Reservoir (TGR) is the largest project, covering an area of 1080 km2. From the beginning, the dam-project came in for criticism on increasing environmental risks due to sub-merging former industrial and urban areas. We simulated dynamics of biotic and abiotic components of the TGR ecosystem (trophic guilds of aquatic organisms, hydrodynamics, nutrients), as well as the behaviour of the herbicidal substance propanil and its metabolites 3,4-Dichloroaniline (DCA) and 3,3',4,4'-tetrachloroazoxybenzene (TCAB). A modelling environment, provided by the AQUATOX software, was adapted to the specific situation at a tributary reach to the Yangtze river 'Daning River'. As the simulated food web contained several interconnected trophic levels, a significant biomagnification of metabolites was demonstrated by our simulation studies. In particular, newly emerging stagnant downstream sections of tributaries exhibited high probabilities due to accumulating pesticides from upstream sources. The common problem of algal blooms in the TGR-region was addressed by dose-response simulation experiments with essential nutrients. Impacts on structure and abundance of populations of aquatic organisms were shown. However, even high nutrient loads resulted in only slight changes of densities of organisms of all trophic levels. Nevertheless, the probabilities for large-scale algal blooms affecting drinking water quality were considered low because of high flow velocities and discharge rates towards the Yangtze River. We see high potential of simulation-based assessments that provide information for risk managers dealing with whole catchment areas. They are put in the position to differentiate the magnitude of impacts of various factors and decide about the most effective remediation measures.

Peer review of the pesticide risk assessment of the active substance propanil.

The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State Italy for the pesticide active substance propanil and the assessment of applications for maximum residue levels (MRLs) are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative use of propanil as a herbicide on rice. MRLs were assessed in rice. The reliable endpoints, appropriate for use in regulatory risk assessment and the proposed MRLs, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Investigation of the binding and simultaneous quantifications of propanil and bromoxynil herbicide concentrations in human serum albumin.

This study reported the use of UV-visible and fluorescence spectroscopy and partial-least-square (PLS) multivariate regression for accurate and simultaneous quantifications of two widely used herbicides, propanil, 3',4'-dichloropropionanilide (PPL) and bromoxynil, 3,5-dibromo-4-hydroxybenzonitrile (BXL) in human serum albumin (HSA) at physiological conditions. The binding affinity and thermodynamic properties of PPL-HSA and BXL-HSA complexes were also investigated. Partial-least-square (PLS) regression was used to collate the variability in the absorption or emission spectra of PPL-HSA and BXL-HSA complexes with PPL and/or BXL concentrations in HSA samples. The binding constants of 7.66× 108 M-1 for PPL-HSA and 4.88× 106 M-1 for BXL-HSA complexes were calculated at physiological conditions (temperature, 310 K; pH 7.4). Thermodynamic parameter values: enthalpy (ΔH) (13.99 kJ mol-1), entropy (ΔS) (0.078 kJ mol-1 K-1), and Gibbs free energy (ΔG) (-10.19 kJ mol-1) were determined for PPL-HSA complexation at physiological conditions. However, differences in thermodynamic property values of: ΔH (-214.3 kJ mol-1), ΔS (-0.563 kJ mol-1 K-1), and ΔG (-39.70 kJ mol-1) were observed for BXL-HSA complexes. The binding constants and negative ΔG values indicated strong binding affinity and thermodynamically favorability of PPL-HSA and BXL-HSA complex formation. Results of the PLS regression calibration showed good linearity (R2 ≥ 0.998289), high sensitivity, and impressive low limit-of-detections (LODs) of 1.38× 10-8 M for PPL and 1.68× 10-8 M for BXL that are comparable and/or lower than many previously reported LODs for herbicide and pesticide analyses. Most importantly, PLS regression is capable of simultaneous quantifications of PPL and BXL concentrations in HSA samples with good accuracy and low errors of 3.66%. UV-visible spectrophotometers and spectrofluorometers are fairly inexpensive, easy to use, and are readily available in almost every laboratory, making this protocol excellent and affordable for routine analysis of weed/pest control chemical residues in humans. The results of this study are significant and remarkable that will provide critical insight into the binding mechanism of herbicide toxicity in humans and non-target organisms, which are of special interest in the area of biomedical study, environmental risk assessment, and ecotoxicology.