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Soil contamination with arsenic (As) can cause phytotoxicity and reduce crop yield. The mechanisms of As toxicity and tolerance are not fully understood. In this study, we used a forward genetics approach to isolate a rice mutant, ahs1, that exhibits hypersensitivity to both arsenate and arsenite. Through genomic resequencing and complementation tests, we identified OsLPD1 as the causal gene, which encodes a putative lipoamide dehydrogenase. OsLPD1 was expressed in the outer cell layer of roots, root meristem cells, and in the mesophyll and vascular tissues of leaves. Subcellular localization and immunoblot analysis demonstrated that OsLPD1 is localized in the stroma of plastids. In vitro assays showed that OsLPD1 exhibited lipoamide dehydrogenase (LPD) activity, which was strongly inhibited by arsenite, but not by arsenate. The ahs1 and OsLPD1 knockout mutants exhibited significantly reduced NADH/NAD+ and GSH/GSSG ratios, along with increased levels of reactive oxygen species and greater oxidative stress in the roots compared with wild-type (WT) plants under As treatment. Additionally, loss-of-function of OsLPD1 also resulted in decreased fatty acid concentrations in rice grain. Taken together, our finding reveals that OsLPD1 plays an important role for maintaining redox homeostasis, conferring tolerance to arsenic stress, and regulating fatty acid biosynthesis in rice.
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Arsênio , Di-Hidrolipoamida Desidrogenase , Ácidos Graxos , Homeostase , Oryza , Proteínas de Plantas , Estresse Fisiológico , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/genética , Arsênio/toxicidade , Arsenitos/toxicidade , Di-Hidrolipoamida Desidrogenase/metabolismo , Di-Hidrolipoamida Desidrogenase/genética , Ácidos Graxos/biossíntese , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Mutação/genética , Oryza/genética , Oryza/efeitos dos fármacos , Oryza/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plastídeos/metabolismo , Plastídeos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genéticaRESUMO
Rice is a dominant source of inorganic arsenic (As) exposure for populations consuming rice as a staple food. Decreasing As accumulation in rice grain is important for improving food safety. Arsenite [As(III)], the main form of As in paddy soil porewater, is taken up inadvertently by OsLsi1 and OsLsi2, the two key transporters for silicon (Si) uptake in rice roots. Here, we investigated whether editing OsLsi1 or OsLsi2 can decrease As accumulation in rice grain without compromising grain yield. We used the CRISPR-Cas9 technology to edit the promoter region of OsLsi1 and the C-terminal coding sequence of OsLsi1 and OsLsi2, and we generated a total of 27 mutants. Uptake and accumulation of Si and As were evaluated in both short-term hydroponic experiments and in a paddy field. Deletion of 1.2-2 kb of the OsLsi1 promoter suppressed OsLsi1 expression in roots and Si uptake markedly and did not affect As(III) uptake or grain As concentration. Some of the OsLsi1 and OsLsi2 coding sequence mutants showed large decreases in the uptake of Si and As(III) as well as large decreases in Si accumulation in rice husks. However, only OsLsi2 mutants showed significant decreases (by up to 63%) in the grain total As concentration. Editing OsLsi2 mainly affected the accumulation of inorganic As in rice grain with little effect on the accumulation of dimethylarsenate (DMA). Grain yields of the OsLsi2 mutants were comparable to those of the wild type. Editing OsLsi2 provides a promising way to reduce As accumulation in rice grain without compromising the grain yield.
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Arsênio , Oryza , Poluentes do Solo , Silício/metabolismo , Oryza/genética , Proteínas de Membrana Transportadoras , Transporte Biológico , SoloRESUMO
Silver nanoparticles (AgNPs) are widely used in daily life and industry because of their excellent antibacterial properties. AgNPs can exist in wastewater in various forms, such as Ag+, Ag2SO4, Ag2CO3, Ag2S, Ag2O, and AgCl. To assess the potential environmental risk of AgNPs and various forms of Ag, their toxic effects were investigated using the common denitrifier species Pseudomonas stutzeri (P. stutzeri). The inhibitory effect of AgNPs and various forms of Ag on P. stutzeri growth and its denitrification performance occurred in a concentration-dependent manner. The denitrification efficiency of P. stutzeri decreased from 95%â¼97% to 89â¼95%, 74â¼95%, and 56â¼85% under low, medium, and high exposure doses, respectively, of AgNPs and various forms of Ag. The changes in cell membrane morphology and increases in lactate dehydrogenase (LDH) release indicated that AgNPs and various forms of Ag damaged the cell membrane of P. stutzeri. Oxidative stress caused by excessive accumulation of reactive oxygen species (ROS) increased superoxide dismutase (SOD) and catalase (CAT) activities and decreased glutathione (GSH) levels. Overall, this study will help elucidate the impact of AgNPs and their transformation products on nitrogen removal efficiency in wastewater biological treatment systems.
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Nanopartículas Metálicas , Pseudomonas stutzeri , Prata/toxicidade , Pseudomonas stutzeri/metabolismo , Nanopartículas Metálicas/toxicidade , Desnitrificação , Águas Residuárias , Nitrogênio , Antioxidantes/metabolismoRESUMO
OBJECTIVE: This study aimed to investigate the significance of miRNA expression levels in peripheral blood lymphocytes of patients clinically diagnosed with pulmonary tuberculosis. METHOD: Pulmonary tuberculosis-related datasets in the Gene Expression Omnibus (GEO) database were analyzed, and DE-miRNAs were screened for Gene Ontology (GO) analysis and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment to construct a DE-miRNA-DE-mRNA network. The peripheral blood lymphocytes of 10 patients with pulmonary tuberculosis, 10 patients with rifampicin-resistant tuberculosis and 10 healthy volunteers were selected for validation of RNA expression levels. qRT-PCR was done to verify the expression of DE-miRNA, and western blotting was done to check the expression levels of genes of associated pathways. RESULTS: Differential expression of miR-660 was found in pulmonary tuberculosis through data analysis and literature mining. The differential expression was also confirmed by qRT-PCR in samples from patients and healthy controls. The expression of miR-660 was significantly upregulated (p < 0.01) in patients with pulmonary tuberculosis and rifampicin-resistant pulmonary tuberculosis compared with the healthy controls. According to western blotting results, the expression levels of P-NF-κB and AKT in patients with pulmonary tuberculosis and NF-κB, P-NF-κB, AKT and p-AKT in patients with rifampicin-resistant tuberculosis were significantly upregulated (p < 0.01). CONCLUSION: The high expression levels of miR-660 may activate the AKT/NF-κB signalling pathway and has the potential to serve as a potential biomarker for the diagnosis of pulmonary tuberculosis.
Assuntos
MicroRNAs , Tuberculose Pulmonar , Humanos , NF-kappa B , Proteínas Proto-Oncogênicas c-akt/genética , Rifampina/farmacologia , Perfilação da Expressão Gênica , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/genética , Linfócitos/metabolismoRESUMO
Dimethylarsenate [DMAs(V)] is a common methylated As species in soils and plants and can cause the physiological disorder straighthead disease in rice. Because DMAs(V) is relatively noncytotoxic, we hypothesize that phytotoxicity of DMAs(V) may arise from trivalent dimethylarsenite [DMAs(III)]. DMAs(III) has been detected in human urine samples but not in environmental samples, likely due to its instability under oxic conditions. We first established methods for preservation and detections of DMAs(III) in soil and plant samples. We showed that DMAs(III) was a major As species in soil solution from an anoxic paddy soil. Enrichment cultures for fermentative, sulfate-reducing, and denitrifying bacteria from the paddy soil could reduce DMAs(V) to DMAs(III). Twenty-two strains of anaerobic bacteria isolated from the soil showed some ability to reduce DMAs(V). Rice plants grown in hydroponic culture with DMAs(V) also showed the ability to reduce DMAs(V) to DMAs(III). Rice plants and grains grown in a flooded paddy soil contained both DMAs(V) and DMAs(III); their concentrations were higher in the spikelets with straighthead disease than those without. DMAs(III) was much more toxic to the protoplasts isolated from rice plants than DMAs(V). Taken together, the ability to reduce DMAs(V) to highly toxic DMAs(III) is common to soil anaerobes and rice plants.
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Arsênio , Oryza , Poluentes do Solo , Humanos , Ácido Cacodílico , SoloRESUMO
INTRODUCTION: Chronic subdural hematoma (CSDH) often occurs 3 weeks to 3 months after brain injury, which is mainly caused by bleeding of the bridging vein. For patients with ventriculoperitoneal (V-P) shunt, excessive drainage can also cause CSDH. We present a rare case of CSDH caused by shunt valve breakdown in brain injury. CASE REPORT: We report a 68-year-old man with V-P shunt for 8 years. He presented with bilateral CSDH with disappearance of lateral ventricles nearly 1 month after a brain injury caused by being hit with a stick. After burr hole drainage (BHD), the patient's symptoms improved and lateral ventricles reappeared, but disappeared rapidly with CSDH recurrence within a short time. We considered the cause to be medium pressure shunt valve breakdown caused by hitting with a stick, which was confirmed by the engineer's test after the operation and excessive drainage of cerebrospinal fluid. BHD replaced the adjustable pressure shunt valve, and the patient recovered. CONCLUSION: V-P shunt is a common operation in neurosurgery, and postoperative shunt valve breakdown may lead to poor outcome. We report a rare case of CSDH caused by shunt valve breakdown due to excessive external forces, suggesting that patients after V-P shunt should pay attention to the protection of the shunt valve.
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Acute subdural hematoma (SDH) is a rare occurrence in chronic myeloid leukemia (CML) patients with only two cases reported in literature. However, sudden severe acute SDH caused by CML has not been reported on. Our patient was admitted for 'sudden unconsciousness for more than 1 hour'. Computed tomography (CT) angiography revealed a large amount of acute SDH on the left side. Physical exam showed the patient's left pupil was dilated and signs of cerebral herniation were present. The preoperative coagulation profile was normal. Emergency craniotomy for hematoma clearance and decompression was performed. During the surgery, a ruptured cerebral artery was located in the perisylvian region and hemostasis was achieved through electrocautery. Pre-operative white blood count was 58,100 cell/µl, with post-operative bone marrow examinationãcytogenetic analysis and RT-PCR detection revealing a diagnosis of CML, for which hydroxyurea chemotherapy was initiated. Leukocyte count of the patient gradually returned to normal. After 24 days, the patient regained consciousness and on day 30, repeat CT scan showed no SDH recurrence. The patient recovered with no neurological deficits and achieved a good prognosis.
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Hematoma Subdural Agudo , Hematoma Subdural Crônico , Leucemia Mielogênica Crônica BCR-ABL Positiva , Humanos , Hematoma Subdural Agudo/cirurgia , Artérias , Leucemia Mielogênica Crônica BCR-ABL Positiva/complicações , Leucemia Mielogênica Crônica BCR-ABL Positiva/diagnóstico , Leucemia Mielogênica Crônica BCR-ABL Positiva/cirurgia , Tomografia Computadorizada por Raios X/efeitos adversos , Angiografia por Tomografia Computadorizada , Hematoma Subdural Crônico/diagnóstico por imagem , Hematoma Subdural Crônico/etiologiaRESUMO
Nonlocal rheologies allow for the modeling of granular flows from the creeping to intermediate flow regimes, using a small number of parameters. In this paper, we report on experiments testing how particle properties affect the model parameters used in the Kamrin & Koval cooperative nonlocal model, using particles of three different shapes (circles, ellipses, and pentagons) and three different materials, including one which allows for the measurement of stresses via photoelasticity. Our experiments are performed on a quasi-2D annular shear cell with a rotating inner wall and a fixed outer wall. Each type of particle is found to exhibit flows which are well-fit by nonlocal rheology, with each particle having a distinct triad of the local, nonlocal, and frictional parameters. While the local parameter b is always approximately unity, the nonlocal parameter A depends sensitively on both the particle shape and material. The critical stress ratio µs, above which Coulomb failure occurs, varies for particles with the same material but different shape, indicating that geometric friction can dominate over material friction.
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Arsenic (As) accumulation in rice is of global concern for human health and international trade. Rice is typically reported to contain inorganic As (iAs) and dimethylated arsenate (DMA), with current food guidelines limiting toxic iAs but not less-toxic DMA. Here, we show that the highly toxic dimethylated monothioarsenate (DMMTA) is also found in rice worldwide and has been unknowingly determined as less-toxic DMA by previous routine analytical methods. Using enzymatic extraction followed by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) analysis with a C18 column, DMMTA was detected in rice grains (n = 103) from a field survey from China and in polished rice grains (n = 140) from a global market-basket survey. Concentration ranged from <0.20 to 34.8 µg/kg (median 10.3 µg/kg), accounting for 0 to 21% of total As. A strong linear correlation was observed in all rice samples between DMA and DMMTA (being 30 ± 8% of DMA) concentrations. This robust relationship allows an estimation of DMMTA in rice grains from the DMA data reported in previous market-basket surveys, showing a general global geographical pattern with DMMTA concentration increasing from the equator toward high-latitude regions. Based on the global occurrence and potential high toxicity, DMMTA in rice should be considered in health risk assessments and for setting food regulations.
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Arsênio , Arsenicais , Oryza , Arsenicais/química , Ácido Cacodílico , Cromatografia Líquida de Alta Pressão , Comércio , Humanos , InternacionalidadeRESUMO
The humic substances (HS) - mediated electron transfer process is of great significance to the reduction and degradation of pollutants and the improvement of soil quality. Different soil conditions lead to different characteristics of HS, resulting in differences in the electron transfer capacity (ETC) of HS. It is unclear how the environmental conditions in soil affect the ETC by affecting on HS. In this study, the response relationship of soil microenvironment, HS and ETC has been studied. The results show that the ETC follows the descending order of: Langshan > Nanchang > Anqing > Beijing > Guilin. There were significant differences in ETC in soil HS in different regions. There were significant differences in electron-donating capacity (EDC) in soil HS in different regions and depths. EDC in soil was higher than electron-accepting capacity (EAC), and on average, are 22.4 times higher than the EAC. The HS components of soils in different regions are different. The most significant differences were in tyrosine-like substances and soluble microbial by-products (SMPs). The five components of the soil HS from Langshan were the most different from those in other regions. There were differences in SMPs and humic-like substances in soils of different depths in Anqing and Guilin. ETC can be affected by the composition of HS components in different regions. The composition of HS at different soil depths in the same regions had little effect on ETC. SMPs can promote ETC and EDC, and tyrosine-like substance can promote EDC. Moisture content, pH and TOC are the main factors affecting the composition of HS components. This results can provide a research basis for the sustainable and safe utilization of agricultural soil.
Assuntos
Substâncias Húmicas , Solo , Agricultura , Elétrons , Substâncias Húmicas/análise , Solo/química , TirosinaRESUMO
Arsenic species transformation in paddy soils has important implications for arsenic accumulation in rice grains and its safety to the consumers. Methylated thioarsenates including highly toxic dimethylated monothioarsenate (DMMTA) have been detected in paddy soils, but their production and dynamics remain poorly understood. In the present study, we first optimized a HPLC-ICP-MS method to quantify methylated thioarsenate species. Using this method together with 10 mM diethylenetriamine pentaacetate (DTPA) to preserve As speciation, we investigated methylated thioarsenate species in porewaters of seven As-contaminated soils incubated under flooded conditions and of two paddy fields. DMMTA was the main methylated thioarsenate species in the porewaters in both incubated soils and paddy fields, with concentrations ranging from 0.2 to 36.2 µg/L and representing ca. 58% of its precursor dimethylarsenate (DMA). The temporal production and dynamics of DMMTA were linked with the DMA concentrations. When soils were drained, DMMTA was converted to DMA. In the two paddy fields, DMMTA concentrations in rice grains were 0.4-10.1 µg/kg. Addition of sulfur fertilizer and rice straw incorporation increased grain DMMTA by 9-28%. These results suggest that DMMTA is an important As species in paddy soils and can accumulate in rice grains, presenting a risk to food safety and human health.
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Arsênio , Oryza , Poluentes do Solo , Ácido Cacodílico , Humanos , Solo , Poluentes do Solo/análiseRESUMO
Rice is a major dietary source of essential mineral nutrients and toxic elements (aka ionome) for humans. However, the genetic basis underlying the variation in ionome is still largely unknown. Here, we mapped 51 and 61 quantitative trait loci (QTLs) controlling the concentrations of 13 and 15 elements in rice (Oryza sativa L.) grain and straw, respectively, using a recombinant inbred lines (RILs) that were grown at three different field sites in 3 years. Several QTLs were repeatedly detected in both grain and straw or in multiple years; the resulting 87 unique QTLs with 17 of them (20%) were co-localized with previously reported corresponding QTLs and 70 were novel ionomic QTLs. At least, 14 genomic clusters that controlled the concentrations of multiple elements were identified. Furthermore, we identified a molybdate transporter gene OsMOT1;1 as the putative causal gene for a QTL controlling molybdenum concentration in both straw and grain. QTL analyses based on the concentrations of multiple elements in both grain and straw of RIL population grown in three field sites in 3 years allow us to identify tissue common QTLs and reproducible QTLs that were validated in multiple years. The identification of ionomic QTLs will be useful in revealing the molecular mechanisms underlying the accumulation of elements in rice and providing the opportunity to reduce the accumulation of toxic elements and enrich the accumulation of beneficial elements in rice grain.
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Proteínas de Transporte de Ânions/genética , Molibdênio/metabolismo , Oryza/genética , Locos de Características Quantitativas/genética , Proteínas de Transporte de Ânions/metabolismo , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Grão Comestível/genética , Grão Comestível/metabolismo , Oryza/metabolismoRESUMO
Straighthead disease is a physiological disorder in rice with symptoms of sterile spikelets, distorted husks, and erect panicles. Methylated arsenic species have been implicated as the causal agent of the disease, but direct evidence is lacking. Here, we investigated whether dimethylarsinic acid (DMA) causes straighthead disease and its effect on the transcriptome of young panicles. DMA addition caused typical straighthead symptoms in hydroponic culture, which were alleviated by silicon addition. DMA addition to soil at the tillering to flowering stages induced straighthead disease. Transgenic rice expressing a bacterial arsenite methyltransferase gene gained the ability to methylate arsenic to mainly DMA, with the consequence of inducing straighthead disease. Field surveys showed that seed setting rate decreased with increasing DMA concentration in the husk, with an EC50 of 0.18 mg kg-1. Transcriptomic analysis showed that 364 and 856 genes were significantly up- and down-regulated, respectively, in the young panicles of DMA-treated plants compared with control, whereas Si addition markedly reduced the number of genes affected. Among the differentially expressed genes, genes related to cell wall modification and oxidative stress responses were the most prominent, suggesting that cell wall metabolism is a sensitive target of DMA toxicity and silicon protects against this toxicity.
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Arsênio , Oryza , Poluentes do Solo , Ácido Cacodílico , Oryza/genética , SoloRESUMO
We analyse the rheology of gravity-driven, dry granular flows in experiments where individual forces within the flow bulk are measured. We release photoelastic discs at the top of an incline to create a quasi-static erodible bed over which flows a steady 2D avalanche. The flowing layers we produce are dense (φ ≈ 0.8), thin (h ≈ 10d), and in the slow to intermediate flow regime (I = 0.1 to 1). Using particle tracking and photoelastic force measurements we report coarse-grained profiles for packing fraction, velocity, shear rate, inertial number, and stress tensor components. In addition, we define a quantitative measure for the rate of generation of new force chain networks and we observe that fluctuations extend below the boundary between dense flow and quasi-static layers. Finally, we evaluate several existing definitions for granular fluidity, and make comparisons among them and the behaviour of our experimentally-measured stress tensor components. Our measurements of the non-dimensional stress ratio µ show that our experiments lie within the local rheological regime, yet we observe rearrangements of the force network extending into the quasi-static layer where shear rates vanish. This elucidates why non-local rheological models rely on the notion of stress diffusion, and we thus propose non-local effects may in fact be dependent on the local force network fluctuation rate.
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The flow of dense granular materials at low inertial numbers cannot be fully characterized by local rheological models; several nonlocal rheologies have recently been developed to address these shortcomings. To test the efficacy of these models across different packing fractions and shear rates, we perform experiments in a quasi-2D annular shear cell with a fixed outer wall and a rotating inner wall, using photoelastic particles. The apparatus is designed to measure both the stress ratio µ (the ratio of shear to normal stress) and the inertial number I through the use of a torque sensor, laser-cut leaf springs, and particle-tracking. We obtain µ(I) curves for several different packing fractions and rotation rates, and successfully find that a single set of model parameters is able to capture the full range of data collected once we account for frictional drag with the bottom plate. Our measurements confirm the prediction that there is a growing lengthscale at a finite value µs, associated with a frictional yield criterion. Finally, we newly identify the physical mechanism behind this transition at µs by observing that it corresponds to a drop in the susceptibility to force chain fluctuations.
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Arsenic (As) biovolatilization is an important component of the global As biogeochemical cycle. Soils can emit various methylarsine gases, but the underlying microbial processes remain unclear. Here, we show that the addition of molybdate (Mo), an inhibitor of sulfate-reducing bacteria, greatly enhanced dimethylarsine evolution from dimethylarsenate [DMAs(V)] added to two paddy soils. Molybdate addition significantly affected the microbial community structure. The aerobic enrichment cultures from both soils volatilized substantial amounts of dimethylarsine from DMAs(V) in the presence of Mo, whereas the anaerobic enrichment cultures did not. A Bacillus strain (CZ-2) capable of reducing DMAs(V) to dimethylarsine was isolated from the aerobic enrichment culture, and its volatilization ability was enhanced by Mo. RNA-seq analysis identified 10 reductase genes upregulated by Mo. Addition of the reducing agent NADH increased dimethylarsine volatilization by strain CZ-2, suggesting that DMAs(V) reductase is an NADH-dependent enzyme. The strain could not methylate arsenite or convert monomethylarsenate and DMAs(V) to trimethylarsine. Our results show that dimethylarsine evolution from DMAs(V) is independent of the As methylation pathway and that Mo enhances dimethylarsine evolution from paddy soils by shifting the microbial community structure and enhancing the reduction of DMAs(V) to dimethylarsine, possibly through upregulating the expression of DMAs(V) reductase gene(s).
Assuntos
Arsenicais , Microbiologia do Solo , Poluentes do Solo , Arsênio , Ácido Cacodílico , Gases , SoloRESUMO
Arsenic (As) bioavailability to rice plants is elevated in flooded paddy soils due to reductive mobilization of arsenite [As(III)]. However, some microorganisms are able to mediate anaerobic As(III) oxidation by coupling to nitrate reduction, thus attenuating As mobility. In this study, we investigated the impact of nitrate additions on As species dynamics in the porewater of four As-contaminated paddy soils. The effects of nitrate on microbial community structure and the abundance and diversity of the As(III) oxidase (aioA) genes were quantified using 16S rRNA sequencing, quantitative PCR, and aioA gene clone libraries. Nitrate additions greatly stimulated anaerobic oxidation of As(III) to As(V) and decreased total soluble As in the porewater in flooded paddy soils. Nitrate additions significantly enhanced the abundance of aioA genes and changed the microbial community structure by increasing the relative abundance of the operational taxonomic units (OTUs) from the genera Acidovorax and Azoarcus. The aioA gene sequences from the Acidovorax related OTU were also stimulated by nitrate. A bacterial strain (ST3) belonging to Acidovorax was isolated from nitrate-amended paddy soil. The strain was able to oxidize As(III) and Fe(II) under anoxic conditions using nitrate as the electron acceptor. Abiotic experiments showed that Fe(II), but not As(III), could be oxidized by nitrite. These results show that nitrate additions can stimulate As(III) oxidation in flooded paddy soils by enhancing the population of anaerobic As(III) oxidizers, offering a potential strategy to decrease As mobility in As-contaminated paddy soils.
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Arsenitos/metabolismo , Solo/química , Nitratos , Oxirredução , RNA Ribossômico 16S/genética , Microbiologia do SoloRESUMO
Microbial arsenic (As) methylation and volatilization are important processes controlling the As biogeochemical cycle in paddy soils. To further understand these processes, we isolated a novel bacterial strain, SM-1, from an As-contaminated paddy soil. SM-1 showed strong As methylation and volatilization abilities, converting almost all arsenite (10 µM) to dimethylarsenate and trimethylarsenic oxide in the medium and trimethylarsine gas into the headspace within 24 h, with trimethylarsine accounting for nearly half of the total As. On the basis of the 16S rRNA sequence, strain SM-1 represents a new species in a new genus within the family Cytophagaceae. Strain SM-1 is abundant in the paddy soil and inoculation of SM-1 greatly enhanced As methylation and volatilization in the soil. An arsenite methyltransferase gene (ArarsM) was cloned from SM-1. When expressed in Escherichia coli, ArArsM conferred the As methylation and volatilization abilities to E. coli and increased its resistance to arsenite. The high As methylation and volatilization abilities of SM-1 are likely attributed to an efficient ArArsM enzyme coupled with low arsenite efflux. These results suggest that strain SM-1 plays an important role in As methylation and volatilization in the paddy soil and has a great potential for As bioremediation.
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Arsênio , Volatilização , Escherichia coli/genética , Metilação , RNA Ribossômico 16S/genética , Solo/química , Poluentes do SoloRESUMO
Inorganic arsenic (As) is highly toxic and ubiquitous in the environment. Inorganic As can be transformed by microbial methylation, which constitutes an important part of the As biogeochemical cycle. In this study, we investigated As biotransformation by Pseudomonas alcaligenes NBRC14159. P. alcaligenes was able to methylate arsenite [As(III)] rapidly to dimethylarsenate and small amounts of trimethylarsenic oxide. An arsenite S-adenosylmethionine methyltransferase, PaArsM, was identified and functionally characterized. PaArsM shares low similarities with other reported ArsM enzymes (<55%). When P. alcaligenes arsM gene (PaarsM) was disrupted, the mutant lost As methylation ability and became more sensitive to As(III). PaarsM was expressed in the absence of As(III) and the expression was further enhanced by As(III) exposure. Heterologous expression of PaarsM in an As-hypersensitive strain of Escherichia coli conferred As(III) resistance. Purified PaArsM protein methylated As(III) to dimethylarsenate as the main product in the medium and also produced dimethylarsine and trimethylarsine gases. We propose that PaArsM plays a role in As methylation and detoxification of As(III) and could be exploited in bioremediation of As-contaminated environments.
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Arsenitos/metabolismo , Proteínas de Bactérias/genética , Metiltransferases/genética , Pseudomonas alcaligenes/enzimologia , Pseudomonas alcaligenes/genética , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Biotransformação , Metiltransferases/química , Metiltransferases/metabolismo , Dados de Sequência Molecular , Pseudomonas alcaligenes/metabolismo , Alinhamento de SequênciaRESUMO
OBJECTIVE: The efficacy of medications for Parkinson's disease (PD) tend to decline over time, which has a serious impact on patients' health and quality of life. To some extent, traditional Chinese medicine (TCM) can resolve the distressing problem of ineffective dopaminergic medication in PD patients. The purpose of this study was to investigate the attitude, acceptance, and independent predictors of TCM in PD patients admitted to the outpatient department of a tertiary hospital. METHODS: A cross-sectional study of PD patients was conducted in the outpatient department of a large tertiary hospital in Beijing from March 2022 to June 2023. A self-report questionnaire was developed to investigate PD patients' attitudes and acceptance of TCM based on the questionnaire. Multivariate logistic regression analyses were also performed to further clarify the independent predictors influencing patients' adoption of TCM therapy. RESULTS: A total of 397 patients completed the questionnaire, of which 78.09% were willing to be treated with TCM and 21.91% indicated that they were not willing to use TCM. Multifactorial logistic regression analysis showed that several parameters were correlated with a patient's willingness to include TCM in their therapeutic regime. These included education level of a bachelor's degree (odds ratio [OR) = 8.554; 95% confidence interval [CI]: 4.112-17.794; P < 0.001, vs junior high school education), living in an urban setting (OR = 8.022; 95% CI: 4.577-14.060; P < 0.001, vs rural), having other underlying diseases (OR = 5.126; 95% CI: 3.078-8.537; P < 0.001, vs none), having previously used TCM (OR = 3.083; 95% CI: 1.852-5.134; P < 0.001, vs not used), believing that TCM therapy is safe (OR = 3.530; 95% CI: 1.446-8.616; P = 0.006, vs not thought), believing that TCM therapy is effective (OR = 3.859; 95% CI: 1.482-10.047; P = 0.006, vs not understood), and being willing to discuss ongoing TCM therapy with an attending physician (OR = 62.468; 95% CI: 30.350-128.574; P < 0.001, vs not informed). CONCLUSION: This study initially investigated the acceptance, attitude, and independent predictors of TCM use among PD patients. To expand the prevalence of TCM use among patients with PD, we recommend to broadening the public outreach for TCM via contemporary means of Internet and broadcast communication, enhancing access to TCM services in rural communities, and strengthening the communication between doctors and patients. Please cite this article as: Wang P, Hong J, Tang ZQ, Gong BZ, Qi XR, Jiang H, Pan B, Chen Q. The acceptance of traditional Chinese medicine among patients with Parkinson's disease: A hospital survey. J Integr Med. 2024; 22(2): 180-187.