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Juvenile hormone (JH) signaling is realized at the gene regulatory level by receptors of the bHLH-PAS transcription factor family. The sesquiterpenoid hormones and their synthetic mimics are agonist ligands of a unique JH receptor (JHR) protein, methoprene-tolerant (MET). Upon binding an agonist to its PAS-B cavity, MET dissociates from a cytoplasmic chaperone complex including HSP83 and concomitantly switches to a bHLH-PAS partner taiman, forming a nuclear, transcriptionally active JHR heterodimer. This course of events resembles the vertebrate aryl hydrocarbon receptor (AHR), activated by a plethora of endogenous and synthetic compounds. Like in AHR, the pliable PAS-B cavity of MET adjusts to diverse ligands and binds them through similar mechanisms. Despite recent progress, we only begin to discern agonist-induced conformational shifts within the PAS-B domain, with the ultimate goal of understanding how these localized changes stimulate the assembly of the active JHR complex and, thus, fully grasp the mechanism of JHR signaling.
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To oxidize trace concentrations of organic contaminants under conditions relevant to surface- and groundwater, air-diffusion cathodes were coupled to stainless-steel cathodes that convert atmospheric O2 into hydrogen peroxide (H2O2), which then was activated to produce hydroxyl radicals (·OH). By separating H2O2 generation from its activation and employing a flow-through electrode consisting of stainless-steel fibers, the two processes could be operated efficiently in a manner that overcame mass-transfer limitations for O2, H2O2, and trace organic contaminants. The flexibility resulting from separate control of the two processes made it possible to avoid both the accumulation of excess H2O2 and the energy losses that take place after H2O2 has been depleted. The decrease in treatment efficacy occurring in the presence of natural organic matter was substantially lower than that typically observed in homogeneous advanced oxidation processes. Experiments conducted with ionized and neutral compounds indicated that electrostatic repulsion prevented negatively charged ·OH scavengers from interfering with the oxidation of neutral contaminants. Energy consumption by the dual-cathode system was lower than values reported for other technologies intended for small-scale drinking water treatment systems. The coordinated operation of these two cathodes has the potential to provide a practical, inexpensive way for point-of-use drinking water treatment.
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Eletrodos , Peróxido de Hidrogênio , Eletricidade Estática , Poluentes Químicos da Água , Purificação da Água , Peróxido de Hidrogênio/química , Purificação da Água/métodos , Poluentes Químicos da Água/química , Oxirredução , Radical Hidroxila/químicaRESUMO
Computational exploration of chemical space is crucial in modern cheminformatics research for accelerating the discovery of new biologically active compounds. In this study, we present a detailed analysis of the chemical library of potential glucocorticoid receptor (GR) ligands generated by the molecular generator, Molpher. To generate the targeted GR library and construct the classification models, structures from the ChEMBL database as well as from the internal IMG library, which was experimentally screened for biological activity in the primary luciferase reporter cell assay, were utilized. The composition of the targeted GR ligand library was compared with a reference library that randomly samples chemical space. A random forest model was used to determine the biological activity of ligands, incorporating its applicability domain using conformal prediction. It was demonstrated that the GR library is significantly enriched with GR ligands compared to the random library. Furthermore, a prospective analysis demonstrated that Molpher successfully designed compounds, which were subsequently experimentally confirmed to be active on the GR. A collection of 34 potential new GR ligands was also identified. Moreover, an important contribution of this study is the establishment of a comprehensive workflow for evaluating computationally generated ligands, particularly those with potential activity against targets that are challenging to dock.
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Receptores de Glucocorticoides , Bibliotecas de Moléculas Pequenas , Receptores de Glucocorticoides/metabolismo , Receptores de Glucocorticoides/química , Ligantes , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/química , HumanosRESUMO
Per- and polyfluoroalkyl substances (PFASs) from aqueous film forming foams (AFFFs) can hinder bioremediation of co-contaminants such as trichloroethene (TCE) and benzene, toluene, ethylbenzene, and xylene (BTEX). Anaerobic dechlorination can require bioaugmentation of Dehalococcoides, and for BTEX, oxygen is often sparged to stimulate in situ aerobic biodegradation. We tested PFAS inhibition to TCE and BTEX bioremediation by exposing an anaerobic TCE-dechlorinating coculture, an aerobic BTEX-degrading enrichment culture, and an anaerobic toluene-degrading enrichment culture to n-dimethyl perfluorohexane sulfonamido amine (AmPr-FHxSA), perfluorohexane sulfonamide (FHxSA), perfluorohexanesulfonic acid (PFHxS), or nonfluorinated surfactant sodium dodecyl sulfate (SDS). The anaerobic TCE-dechlorinating coculture was resistant to individual PFAS exposures but was inhibited by >1000× diluted AFFF. FHxSA and AmPr-FHxSA inhibited the aerobic BTEX-degrading enrichment. The anaerobic toluene-degrading enrichment was not inhibited by AFFF or individual PFASs. Increases in amino acids in the anaerobic TCE-dechlorinating coculture compared to the control indicated stress response, whereas the BTEX culture exhibited lower concentrations of all amino acids upon exposure to most surfactants (both fluorinated and nonfluorinated) compared to the control. These data suggest the main mechanisms of microbial toxicity are related to interactions with cell membrane synthesis as well as protein stress signaling.
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Biodegradação Ambiental , Hidrocarbonetos Aromáticos , Hidrocarbonetos Aromáticos/metabolismo , Tricloroetileno/metabolismo , Sulfonamidas/metabolismoRESUMO
Endogenous neurosteroids (NS) and their synthetic analogs, neuroactive steroids (NAS), are potentially useful drug-like compounds affecting the pathophysiology of miscellaneous central nervous system disorders (e.g. Alzheimer´s disease, epilepsy, depression, etc.). Additionally, NS have been shown to promote neuron viability and neurite outgrowth upon injury. The molecular, structural and physicochemical basis of the NS effect on neurons is so far not fully understood, and the development of new, biologically relevant assays is essential for their comparative analysis and for assessment of their mechanism of action. Here, we report the development of a novel, plate-based, high-content in vitro assay for screening of NS and newly synthesized, 5ß-reduced NAS for the promotion of postnatal neuron survival and neurite growth using fluorescent, postnatal mixed cortical neuron cultures isolated from thy1-YFP transgenic mice. The screen allows a detailed time course analysis of different parameters, such as the number of neurons or neurite lengths of 7-day, in vitro neuron cultures. Using the screen, we identify a new NAS, compound 42, that promotes the survival and growth of postnatal neurons significantly better than several endogenous NS (dehydroepiandrosterone, progesterone, and allopregnanolone). Interestingly, we demonstrate that compound 42 also promotes the proliferation of glia (in particular oligodendrocytes) and that the glial function is critical for its neuron growth support. Computational analysis of the biological data and calculated physicochemical properties of tested NS and NAS demonstrated that their biological activity is proportional to their lipophilicity. Together, the screen proves useful for the selection of neuron-active NAS and the comparative evaluation of their biologically relevant structural and physicochemical features.
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Neuroesteroides , Camundongos , Animais , Neurônios , Neuritos , Progesterona/farmacologia , Oligodendroglia , Camundongos TransgênicosRESUMO
In situ chemical oxidation (ISCO) using peroxydisulfate has become more popular in the remediation of soils and shallow groundwater contaminated with organic chemicals. Researchers have studied the chemistry of peroxydisulfate and the oxidative species produced upon its decomposition (i.e., sulfate radical and hydroxyl radical) for over five decades, describing reaction kinetics, mechanisms, and product formation in great detail. However, if this information is to be useful to practitioners seeking to optimize the use of peroxydisulfate in the remediation of hazardous waste sites, the relevant conditions of high oxidant concentrations and the presence of minerals and solutes that affect radical chain reactions must be considered. The objectives of this Review are to provide insights into the chemistry of peroxydisulfate-based ISCO that can enable more efficient operation of these systems and to identify research needed to improve understanding of system performance. By gaining a deeper understanding of the underlying chemistry of these complex systems, it may be possible to improve the design and operation of peroxydisulfate-based ISCO remediation systems.
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Água Subterrânea , Poluentes Químicos da Água , Óxidos/química , Oxirredução , Oxidantes/química , Minerais/química , Solo/química , Poluentes Químicos da Água/análise , Água Subterrânea/químicaRESUMO
Scarcity of freshwater for agriculture has led to increased utilization of treated wastewater (TWW), establishing it as a significant and reliable source of irrigation water. However, years of research indicate that if not managed adequately, TWW may deleteriously affect soil functioning and plant productivity, and pose a hazard to human and environmental health. This review leverages the experience of researchers, stakeholders, and policymakers from Israel, the United-States, and Europe to present a holistic, multidisciplinary perspective on maximizing the benefits from municipal TWW use for irrigation. We specifically draw on the extensive knowledge gained in Israel, a world leader in agricultural TWW implementation. The first two sections of the work set the foundation for understanding current challenges involved with the use of TWW, detailing known and emerging agronomic and environmental issues (such as salinity and phytotoxicity) and public health risks (such as contaminants of emerging concern and pathogens). The work then presents solutions to address these challenges, including technological and agronomic management-based solutions as well as source control policies. The concluding section presents suggestions for the path forward, emphasizing the importance of improving links between research and policy, and better outreach to the public and agricultural practitioners. We use this platform as a call for action, to form a global harmonized data system that will centralize scientific findings on agronomic, environmental and public health effects of TWW irrigation. Insights from such global collaboration will help to mitigate risks, and facilitate more sustainable use of TWW for food production in the future.
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Per- and polyfluoroalkyl substances (PFAS) exist in contaminated groundwater, surface water, soil, and sediments from use of aqueous film forming foams (AFFFs). Under these conditions PFAS exhibit unusual behavior due to their surfactant properties, namely, aggregation and surface activity. Environmental factors such as salinity can affect these properties, and complicate efforts to monitor PFAS. The effect of high salinity matrices on the critical micelle concentration (CMC) of a AFFF formulation manufactured by 3M and the surface accumulation of PFAS was assessed with surface tension isotherm measurements and bench-scale experiments quantifying PFAS at the air-water interface. Conditions typical of brackish and saline waters substantially depressed the CMC of the AFFF by over 50% and increased the interfacial mass accumulation of PFAS in the AFFF mixture by up to a factor of 3, relative to values measured in ultrapure water. These results indicate that high salinity matrices increase the aggregation and surface activity of PFAS in mixtures, which are key properties affecting their transport.
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Fluorocarbonos , Água Subterrânea , Poluentes Químicos da Água , Adsorção , Salinidade , Poluentes Químicos da Água/análise , Fluorocarbonos/análiseRESUMO
Subsurface treatment systems, such as constructed wetlands, riverbank filtration systems, and managed aquifer recharge systems, offer a low-cost means of removing trace organic contaminants from treated municipal wastewater. To assess the processes through which trace organic contaminants are removed in subsurface treatment systems, pharmaceuticals and several major metabolites were measured in porewater, sediment, and plants within a horizontal levee (i.e., a subsurface flow wetland that receives treated municipal wastewater). Concentrations of trace organic contaminants in each wetland compartment rapidly declined along the flow path. Mass balance calculations, analysis of transformation products, microcosm experiments, and one-dimensional transport modeling demonstrated that more than 60% of the contaminant removal could be attributed to transformation. Monitoring of the system with and without nitrate in the wetland inflow indicated that relatively biodegradable trace organic contaminants, such as acyclovir and metoprolol, were rapidly transformed under both operating conditions. Trace organic contaminants that are normally persistent in biological treatment systems (e.g., sulfamethoxazole and carbamazepine) were removed only when Fe(III)- and sulfate-reducing conditions were observed. Minor structural modifications to trace organic contaminants (e.g., hydroxylation) altered the pathways and extents of trace organic contaminant transformation under different redox conditions. These findings indicate that subsurface treatment systems can be designed to remove both labile and persistent trace organic contaminants via transformation if they are designed and operated in a manner that results in sulfate-and Fe(III)-reducing conditions.
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Poluentes Químicos da Água , Purificação da Água , Águas Residuárias , Compostos Férricos , Sulfatos/análise , Purificação da Água/métodos , Compostos Orgânicos/análise , Poluentes Químicos da Água/análise , Áreas Alagadas , Eliminação de Resíduos Líquidos/métodosRESUMO
Fully halogenated compounds are difficult to remediate by in situ chemical oxidation (ISCO) because carbon-halogen bonds react very slowly with the species that typically initiate contaminant transformation: sulfate radical (SO4â¢-) and hydroxyl radical (â¢OH). To enable the remediation of this class of contaminants by persulfate (S2O82-)-based ISCO, we employed a two-phase process to dehalogenate and oxidize a representative halogenated compound (i.e., hexachloroethane). In the first phase, a relatively high concentration of ethanol (1.8 M) was added, along with concentrations of S2O82- that are typically used for ISCO (i.e., 450 mM). Hexachloroethane underwent rapid dehalogenation when carbon-centered radicals produced by the reaction of ethanol and radicals formed during S2O82- decomposition reacted with carbon-halogen bonds. Unlike conventional ISCO treatment, hexachloroethane transformation and S2O82- decomposition took place on the time scale of days without external heating or base addition. The presence of O2, Cl-, and NO3- delayed the onset of hexachloroethane transformation when low concentrations of S2O82- (10 mM) were used, but these solutes had negligible effects when S2O82- was present at concentrations typical of in situ remediation (450 mM). The second phase of the reaction was initiated after most of the ethanol had been depleted when thermolytic S2O82- decomposition resulted in production of SO4â¢- that oxidized the partially dehalogenated transformation products. With proper precautions, S2O82--based ISCO with ethanol could be a useful remediation technology for sites contaminated with fully halogenated compounds.
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Hidrocarbonetos Clorados , Racepinefrina , Compostos Orgânicos , Carbono , Etanol , HalogêniosRESUMO
Several billion metric tons per year of durable carbon dioxide removal (CDR) will be needed by mid-century to prevent catastrophic climate warming, and many new approaches must be rapidly scaled to ensure this target is met. Geologically permanent sequestration of carbon dioxide (CO2) in carbonate minerals-carbon mineralization-requires two moles of alkalinity and one mole of a CO2-reactive metal such as calcium or magnesium per mole of CO2 captured. Chemical weathering of geological materials can supply both ingredients, but weathering reactions must be accelerated to achieve targets for durable CDR. Here, a scalable CDR and mineralization process is reported in which water electrolysis is used to produce sulfuric acid for accelerated weathering, while a base is used to permanently sequester CO2 from air into carbonate minerals. The process can be integrated into existing extractive processes by reacting produced sulfuric acid with critical element feedstocks that neutralize acidity (e.g., rock phosphorus or ultramafic rock mine tailings), with calcium- and magnesium-bearing sulfate wastes electrolytically upcycled. The highest reported efficiency of electrolytic sulfuric acid production is achieved by maintaining catholyte feed conditions that minimize Faradaic losses by hydroxide permeation of the membrane-separated electrochemical cell. The industrial implementation of this process provides a pathway to gigaton-scale CO2 removal and sequestration during the production of critical elements needed for decarbonizing global energy infrastructure and feeding the world.
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Fungi and laccase mediator systems (LMSs) have a proven track record of oxidizing recalcitrant organic compounds. There has been considerable interest in applying LMSs to the treatment of perfluoroalkyl acids (PFAAs), a class of ubiquitous and persistent environmental contaminants. Some laboratory experiments have indicated modest losses of PFAAs over extended periods, but there have been no clear demonstrations of a transformation mechanism or the kinetics that would be needed for remediation applications. We set out to determine if this was a question of identifying and optimizing a rate-limiting step but discovered that observed losses of PFAAs were experimental artifacts. While unable to replicate the oxidation of PFAAs, we show that interactions of the PFAA compounds with laccase and laccase mediator mixtures could cause an artifact that mimics transformation (â²60%) of PFAAs. Furthermore, we employed a surrogate compound, carbamazepine (CBZ), and electron paramagnetic resonance spectroscopy to probe the formation of the radical species that had been proposed to be responsible for contaminant oxidation. We confirmed that under conditions where sufficient radical concentrations were produced to oxidize CBZ, no PFAA removal took place.
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Ammonia monooxygenase and analogous oxygenase enzymes contribute to pharmaceutical biotransformation in activated sludge. In this study, we hypothesized that methane monooxygenase can enhance pharmaceutical biotransformation within the benthic, diffuse periphytic sediments (i.e., "biomat") of a shallow, open-water constructed wetland. To test this hypothesis, we combined field-scale metatranscriptomics, porewater geochemistry, and methane gas fluxes to inform microcosms targeting methane monooxygenase activity and its potential role in pharmaceutical biotransformation. In the field, sulfamethoxazole concentrations decreased within surficial biomat layers where genes encoding for the particulate methane monooxygenase (pMMO) were transcribed by a novel methanotroph classified as Methylotetracoccus. Inhibition microcosms provided independent confirmation that methane oxidation was mediated by the pMMO. In these same incubations, sulfamethoxazole biotransformation was stimulated proportional to aerobic methane-oxidizing activity and exhibited negligible removal in the absence of methane, in the presence of methane and pMMO inhibitors, and under anoxia. Nitrate reduction was similarly enhanced under aerobic methane-oxidizing conditions with rates several times faster than for canonical denitrification. Collectively, our results provide convergent in situ and laboratory evidence that methane-oxidizing activity can enhance sulfamethoxazole biotransformation, with possible implications for the combined removal of nitrogen and trace organic contaminants in wetland sediments.
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Metano , Áreas Alagadas , Oxirredução , Minerais , BiotransformaçãoRESUMO
Low-cost stainless-steel electrodes can activate hydrogen peroxide (H2O2) by converting it into a hydroxyl radical (â¢OH) and other reactive oxidants. At an applied potential of +0.020 V, the stainless-steel electrode produced â¢OH with a yield that was over an order of magnitude higher than that reported for other systems that employ iron oxides as catalysts under circumneutral pH conditions. Decreasing the applied potential at pH 8 and 9 enhanced the rate of H2O2 loss by shifting the process to a reaction mechanism that resulted in the formation of an Fe(IV) species. Significant metal leaching was only observed under acidic pH conditions (i.e., at pH <6), with the release of dissolved Fe and Cr occurring as the thickness of the passivation layer decreased. Despite the relatively high yield of â¢OH production under circumneutral pH conditions, most of the oxidants were scavenged by the electrode surface when contaminant concentrations comparable to those expected in drinking water sources were tested. The stainless-steel electrode efficiently removed trace organic contaminants from an authentic surface water sample without contaminating the water with Fe and Cr. With further development, stainless-steel electrodes could provide a cost-effective alternative to other H2O2 activation processes, such as those by ultraviolet light.
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Oxidantes , Poluentes Químicos da Água , Peróxido de Hidrogênio , Aço Inoxidável , Oxirredução , Eletrodos , ÁguaRESUMO
Cytotoxicity of de novo purine synthesis (DNPS) metabolites is critical to the pathogenesis of three known and one putative autosomal recessive disorder affecting DNPS. These rare disorders are caused by biallelic mutations in the DNPS genes phosphoribosylformylglycineamidine synthase (PFAS), phosphoribosylaminoimidazolecarboxylase/phosphoribosylaminoimidazolesuccinocarboxamide synthase (PAICS), adenylosuccinate lyase (ADSL), and aminoimidazole carboxamide ribonucleotide transformylase/inosine monophosphate cyclohydrolase (ATIC) and are clinically characterized by developmental abnormalities, psychomotor retardation, and nonspecific neurological impairment. At a biochemical level, loss of function of specific mutated enzymes results in elevated levels of DNPS ribosides in body fluids. The main pathogenic effect is attributed to the accumulation of DNPS ribosides, which are postulated to be toxic to the organism. Therefore, we decided to characterize the uptake and flux of several DNPS metabolites in HeLa cells and the impact of DNPS metabolites to viability of cancer cell lines and primary skin fibroblasts. We treated cells with DNPS metabolites and followed their flux in purine synthesis and degradation. In this study, we show for the first time the transport of formylglycinamide ribotide (FGAR), aminoimidazole ribotide (AIR), succinylaminoimidazolecarboxamide ribotide (SAICAR), and aminoimidazolecarboxamide ribotide (AICAR) into cells and their flux in DNPS and the degradation pathway. We found diminished cell viability mostly in the presence of FGAR and AIR. Our results suggest that direct cellular toxicity of DNPS metabolites may not be the primary pathogenetic mechanism in these disorders.
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Juvenile hormones (JHs) control insect metamorphosis and reproduction. JHs act through a receptor complex consisting of methoprene-tolerant (Met) and taiman (Tai) proteins to induce transcription of specific genes. Among chemically diverse synthetic JH mimics (juvenoids), some of which serve as insecticides, unique peptidic juvenoids stand out as being highly potent yet exquisitely selective to a specific family of true bugs. Their mode of action is unknown. Here we demonstrate that, like established JH receptor agonists, peptidic juvenoids act upon the JHR Met to halt metamorphosis in larvae of the linden bug, Pyrrhocoris apterus. Peptidic juvenoids induced ligand-dependent dimerization between Met and Tai proteins from P. apterus but, consistent with their selectivity, not from other insects. A cell-based split-luciferase system revealed that the Met-Tai complex assembled within minutes of agonist presence. To explore the potential of juvenoid peptides, we synthesized 120 new derivatives and tested them in Met-Tai interaction assays. While many substituents led to loss of activity, improved derivatives active at sub-nanomolar range outperformed hitherto existing peptidic and classical juvenoids including fenoxycarb. Their potency in inducing Met-Tai interaction corresponded with the capacity to block metamorphosis in P. apterus larvae and to stimulate oogenesis in reproductively arrested adult females. Molecular modeling demonstrated that the high potency correlates with high affinity. This is a result of malleability of the ligand-binding pocket of P. apterus Met that allows larger peptidic ligands to maximize their contact surface. Our data establish peptidic juvenoids as highly potent and species-selective novel JHR agonists.
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Hormônios Juvenis , Metoprene , Animais , Feminino , Hormônios Juvenis/metabolismo , Ligantes , Metoprene/metabolismo , Insetos/metabolismo , Reprodução , Larva , Peptídeos/farmacologiaRESUMO
Stormwater runoff capture and groundwater recharge can provide a sustainable means of augmenting the local water resources in water-stressed cities while simultaneously mitigating flood risk, provided that these processes do not compromise groundwater quality. We developed and tested for one year an innovative pilot-scale stormwater treatment train that employs cost-effective engineered geomedia in a continuous-flow unit-process system to remove contaminants from urban runoff during aquifer recharge. The system consisted of an iron-enhanced sand filter for phosphate removal, a woodchip bioreactor for nitrate removal coupled to an aeration step, and columns packed with different configurations of biochar- and manganese oxide-containing sand to remove trace metals and persistent, mobile, and toxic trace organic contaminants. During conditioning with authentic stormwater runoff over an extended period (8 months), the woodchip bioreactor removed 98% of the influent nitrate (9 g-N m-3 d-1), while phosphate broke through the iron-enhanced sand filter. During the challenge test (4 months), geomedia removed more than 80% of the mass of metals and trace organic compounds. Column hydraulic performance was stable during the entire study, and the weathered biochar and manganese oxide were effective at removing trace organic contaminants and metals, respectively. Under conditions likely encountered in the field, sustained nutrient removal is probable, but polar organic compounds such as 2,4-D could breakthrough after about a decade for conditions at the study site.
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Purificação da Água , Chuva , Nitratos , Abastecimento de Água , Metais , Compostos Orgânicos , Organofosfatos , Fosfatos , FerroRESUMO
Sites impacted by aqueous film-forming foam (AFFF) contain co-contaminants that can stimulate biotransformation of polyfluoroalkyl substances. Here, we compare how microbial enrichments from AFFF-impacted soil amended with diethyl glycol monobutyl ether (found in AFFF), aromatic hydrocarbons (present in co-released fuels), acetate, and methane (substrates used or formed during bioremediation) impact the aerobic biotransformation of an AFFF-derived six-carbon electrochemical fluorination (ECF) precursor N-dimethyl ammonio propyl perfluorohexane sulfonamide (AmPr-FHxSA). We found that methane- and acetate-oxidizing cultures resulted in the highest yields of identifiable products (38 and 30%, respectively), including perfluorohexane sulfonamide (FHxSA) and perfluorohexane sulfonic acid (PFHxS). Using these data, we propose and detail a transformation pathway. Additionally, we examined chemical oxidation products of AmPr-FHxSA and FHxSA to provide insights on remediation strategies for AmPr-FHxSA. We demonstrate mineralization of these compounds using the sulfate radical and test their transformation during the total oxidizable precursor (TOP) assay. While perfluorohexanoic acid accounted for over 95% of the products formed, we demonstrate here for the first time two ECF-based precursors, AmPr-FHxSA and FHxSA, that produce PFHxS during the TOP assay. These findings have implications for monitoring poly- and perfluoroalkyl substances during site remediation and application of the TOP assay at sites impacted by ECF-based precursors.
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Fluorocarbonos , Poluentes Químicos da Água , Fluorocarbonos/análise , Carbono , Poluentes Químicos da Água/análise , Água , Sulfanilamida , Sulfonamidas , MetanoRESUMO
In shallow, open-water engineered wetlands, design parameters select for a photosynthetic microbial biomat capable of robust pharmaceutical biotransformation, yet the contributions of specific microbial processes remain unclear. Here, we combined genome-resolved metatranscriptomics and oxygen profiling of a field-scale biomat to inform laboratory inhibition microcosms amended with a suite of pharmaceuticals. Our analyses revealed a dynamic surficial layer harboring oxic-anoxic cycling and simultaneous photosynthetic, nitrifying, and denitrifying microbial transcription spanning nine bacterial phyla, with unbinned eukaryotic scaffolds suggesting a dominance of diatoms. In the laboratory, photosynthesis, nitrification, and denitrification were broadly decoupled by incubating oxic and anoxic microcosms in the presence and absence of light and nitrogen cycling enzyme inhibitors. Through combining microcosm inhibition data with field-scale metagenomics, we inferred microbial clades responsible for biotransformation associated with membrane-bound nitrate reductase activity (emtricitabine, trimethoprim, and atenolol), nitrous oxide reduction (trimethoprim), ammonium oxidation (trimethoprim and emtricitabine), and photosynthesis (metoprolol). Monitoring of transformation products of atenolol and emtricitabine confirmed that inhibition was specific to biotransformation and highlighted the value of oscillating redox environments for the further transformation of atenolol acid. Our findings shed light on microbial processes contributing to pharmaceutical biotransformation in open-water wetlands with implications for similar nature-based treatment systems.