1
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Funck D, Sinn M, Forlani G, Hartig JS. Guanidine production by plant homoarginine-6-hydroxylases. eLife 2024; 12:RP91458. [PMID: 38619227 PMCID: PMC11018352 DOI: 10.7554/elife.91458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024] Open
Abstract
Metabolism and biological functions of the nitrogen-rich compound guanidine have long been neglected. The discovery of four classes of guanidine-sensing riboswitches and two pathways for guanidine degradation in bacteria hint at widespread sources of unconjugated guanidine in nature. So far, only three enzymes from a narrow range of bacteria and fungi have been shown to produce guanidine, with the ethylene-forming enzyme (EFE) as the most prominent example. Here, we show that a related class of Fe2+- and 2-oxoglutarate-dependent dioxygenases (2-ODD-C23) highly conserved among plants and algae catalyze the hydroxylation of homoarginine at the C6-position. Spontaneous decay of 6-hydroxyhomoarginine yields guanidine and 2-aminoadipate-6-semialdehyde. The latter can be reduced to pipecolate by pyrroline-5-carboxylate reductase but more likely is oxidized to aminoadipate by aldehyde dehydrogenase ALDH7B in vivo. Arabidopsis has three 2-ODD-C23 isoforms, among which Din11 is unusual because it also accepted arginine as substrate, which was not the case for the other 2-ODD-C23 isoforms from Arabidopsis or other plants. In contrast to EFE, none of the three Arabidopsis enzymes produced ethylene. Guanidine contents were typically between 10 and 20 nmol*(g fresh weight)-1 in Arabidopsis but increased to 100 or 300 nmol*(g fresh weight)-1 after homoarginine feeding or treatment with Din11-inducing methyljasmonate, respectively. In 2-ODD-C23 triple mutants, the guanidine content was strongly reduced, whereas it increased in overexpression plants. We discuss the implications of the finding of widespread guanidine-producing enzymes in photosynthetic eukaryotes as a so far underestimated branch of the bio-geochemical nitrogen cycle and propose possible functions of natural guanidine production.
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Affiliation(s)
- Dietmar Funck
- Department of Chemistry, University of KonstanzKonstanzGermany
| | - Malte Sinn
- Department of Chemistry, University of KonstanzKonstanzGermany
| | - Giuseppe Forlani
- Department of Life Science and Biotechnology, University of FerraraFerraraItaly
| | - Jörg S Hartig
- Department of Chemistry, University of KonstanzKonstanzGermany
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2
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Dong L, Li S, Huang J, Li WJ, Ali M. Co-occurrence, toxicity, and biotransformation pathways of metformin and its intermediate product guanylurea: Current state and future prospects for enhanced biodegradation strategy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171108. [PMID: 38395159 DOI: 10.1016/j.scitotenv.2024.171108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/29/2024] [Accepted: 02/18/2024] [Indexed: 02/25/2024]
Abstract
Accumulation of metformin and its biotransformation product "guanylurea" are posing an increasing concern due to their low biodegradability under natural attenuated conditions. Therefore, in this study, we reviewed the unavoidable function of metformin in human body and the route of its release in different water ecosystems. In addition, metformin and its biotransformation product guanylurea in aquatic environments caused certain toxic effects on aquatic organisms which include neurotoxicity, endocrine disruption, production of ROS, and acetylcholinesterase disturbance in aquatic organisms. Moreover, microorganisms are the first to expose and deal with the release of these contaminants, therefore, the mechanisms of biodegradation pathways of metformin and guanylurea under aerobic and anaerobic environments were studied. It has been reported that certain microbes, such as Aminobacter sp. and Pseudomonas putida can carry potential enzymatic pathways to degrade the dead-end product "guanylurea", and hence guanylurea is no longer the dead-end product of metformin. However, these microbes can easily be affected by certain geochemical cycles, therefore, we proposed certain strategies that can be helpful in the enhanced biodegradation of metformin and its biotransformation product guanylurea. A better understanding of the biodegradation potential is imperative to improve the use of these approaches for the sustainable and cost-effective remediation of the emerging contaminants of concern, metformin and guanylurea in the near future.
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Affiliation(s)
- Lei Dong
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shuai Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China; School of Life Science, Jiaying University, Meizhou, China
| | - Jie Huang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China; State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
| | - Mukhtiar Ali
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China; Advanced Water Technology Laboratory, National University of Singapore (Suzhou) Research Institute, Suzhou, Jiangsu 215123, China..
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3
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Baldasso V, Sayen S, Gomes CAR, Frunzo L, Almeida CMR, Guillon E. Metformin and lamotrigine sorption on a digestate amended soil in presence of trace metal contamination. JOURNAL OF HAZARDOUS MATERIALS 2024; 466:133635. [PMID: 38306838 DOI: 10.1016/j.jhazmat.2024.133635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/04/2024]
Abstract
The antidiabetic drug metformin and antiepileptic drug lamotrigine are contaminants of emerging concern that have been detected in biowaste-derived amendments and in the environment, and their fate must be carefully studied. This work aimed to evaluate their sorption behaviour on soil upon digestate application. Experiments were conducted on soil and digestate-amended soil as a function of time to study kinetic processes, and at equilibrium also regarding the influence of trace metals (Pb, Ni, Cr, Co, Cu, Zn) at ratio pharmaceutical/metal 1/1, 1/10, and 1/100. Pharmaceutical desorption experiments were also conducted to assess their potential mobility to groundwater. Results revealed that digestate amendment increased metformin and lamotrigine adsorbed amounts by 210% and 240%, respectively, increasing organic matter content. Metformin adsorption kinetics were best described by Langmuir model and those of lamotrigine by Elovich and intraparticle diffusion models. Trace metals did not significantly affect the adsorption of metformin in amended soil while significantly decreased that of lamotrigine by 12-39%, with exception for Cu2+ that increased both pharmaceuticals adsorbed amounts by 5 - 8%. This study highlighted the influence of digestate amendment on pharmaceutical adsorption and fate in soil, which must be considered in the circular economy scenario of waste-to-resource.
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Affiliation(s)
- Veronica Baldasso
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Portugal; Chemistry and Biochemistry Department, Faculty of Sciences, University of Porto, Porto, Portugal; Molecular Chemistry Institute of Reims, ICMR UMR CNRS 7312, University of Reims Champagne-Ardenne, Reims, France.
| | - Stéphanie Sayen
- Molecular Chemistry Institute of Reims, ICMR UMR CNRS 7312, University of Reims Champagne-Ardenne, Reims, France.
| | - Carlos A R Gomes
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Portugal; Chemistry and Biochemistry Department, Faculty of Sciences, University of Porto, Porto, Portugal
| | - Luigi Frunzo
- Department of Mathematics and Applications Renato Caccioppoli, University of Naples Federico II, Napoli, Italy
| | - C Marisa R Almeida
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Portugal; Chemistry and Biochemistry Department, Faculty of Sciences, University of Porto, Porto, Portugal
| | - Emmanuel Guillon
- Molecular Chemistry Institute of Reims, ICMR UMR CNRS 7312, University of Reims Champagne-Ardenne, Reims, France
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4
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Tassoulas LJ, Rankin JA, Elias MH, Wackett LP. Dinickel enzyme evolved to metabolize the pharmaceutical metformin and its implications for wastewater and human microbiomes. Proc Natl Acad Sci U S A 2024; 121:e2312652121. [PMID: 38408229 DOI: 10.1073/pnas.2312652121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 01/12/2024] [Indexed: 02/28/2024] Open
Abstract
Metformin is the first-line treatment for type II diabetes patients and a pervasive pollutant with more than 180 million kg ingested globally and entering wastewater. The drug's direct mode of action is currently unknown but is linked to effects on gut microbiomes and may involve specific gut microbial reactions to the drug. In wastewater treatment plants, metformin is known to be transformed by microbes to guanylurea, although genes encoding this metabolism had not been elucidated. In the present study, we revealed the function of two genes responsible for metformin decomposition (mfmA and mfmB) found in isolated bacteria from activated sludge. MfmA and MfmB form an active heterocomplex (MfmAB) and are members of the ureohydrolase protein superfamily with binuclear metal-dependent activity. MfmAB is nickel-dependent and catalyzes the hydrolysis of metformin to dimethylamine and guanylurea with a catalytic efficiency (kcat/KM) of 9.6 × 103 M-1s-1 and KM for metformin of 0.82 mM. MfmAB shows preferential activity for metformin, being able to discriminate other close substrates by several orders of magnitude. Crystal structures of MfmAB show coordination of binuclear nickel bound in the active site of the MfmA subunit but not MfmB subunits, indicating that MfmA is the active site for the MfmAB complex. Mutagenesis of residues conserved in the MfmA active site revealed those critical to metformin hydrolase activity and its small substrate binding pocket allowed for modeling of bound metformin. This study characterizes the products of the mfmAB genes identified in wastewater treatment plants on three continents, suggesting that metformin hydrolase is widespread globally in wastewater.
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Affiliation(s)
- Lambros J Tassoulas
- Department of Biochemistry, Biophysics, and Molecular Biology, University of Minnesota, Minneapolis, MN 55455
- BioTechnology Institute, University of Minnesota, St. Paul, MN 55108
| | - Joel A Rankin
- Department of Biochemistry, Biophysics, and Molecular Biology, University of Minnesota, Minneapolis, MN 55455
- BioTechnology Institute, University of Minnesota, St. Paul, MN 55108
| | - Mikael H Elias
- Department of Biochemistry, Biophysics, and Molecular Biology, University of Minnesota, Minneapolis, MN 55455
- BioTechnology Institute, University of Minnesota, St. Paul, MN 55108
| | - Lawrence P Wackett
- Department of Biochemistry, Biophysics, and Molecular Biology, University of Minnesota, Minneapolis, MN 55455
- BioTechnology Institute, University of Minnesota, St. Paul, MN 55108
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5
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Lucero RM, Demirer K, Yeh TJ, Stockbridge RB. Transport of metformin metabolites by guanidinium exporters of the small multidrug resistance family. J Gen Physiol 2024; 156:e202313464. [PMID: 38294434 PMCID: PMC10829512 DOI: 10.1085/jgp.202313464] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/01/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
Proteins from the small multidrug resistance (SMR) family are frequently associated with horizontally transferred multidrug resistance gene arrays found in bacteria from wastewater and the human-adjacent biosphere. Recent studies suggest that a subset of SMR transporters might participate in the metabolism of the common pharmaceutical metformin by bacterial consortia. Here, we show that both genomic and plasmid-associated transporters of the SMRGdx functional subtype export byproducts of microbial metformin metabolism, with particularly high export efficiency for guanylurea. We use solid-supported membrane electrophysiology to evaluate the transport kinetics for guanylurea and native substrate guanidinium by four representative SMRGdx homologs. Using an internal reference to normalize independent electrophysiology experiments, we show that transport rates are comparable for genomic and plasmid-associated SMRGdx homologs, and using a proteoliposome-based transport assay, we show that 2 proton:1 substrate transport stoichiometry is maintained. Additional characterization of guanidinium and guanylurea export properties focuses on the structurally characterized homolog, Gdx-Clo, for which we examined the pH dependence and thermodynamics of substrate binding and solved an x-ray crystal structure with guanylurea bound. Together, these experiments contribute in two main ways. By providing the first detailed kinetic examination of the structurally characterized SMRGdx homolog Gdx-Clo, they provide a functional framework that will inform future mechanistic studies of this model transport protein. Second, this study casts light on a potential role for SMRGdx transporters in microbial handling of metformin and its microbial metabolic byproducts, providing insight into how native transport physiologies are co-opted to contend with new selective pressures.
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Affiliation(s)
- Rachael M. Lucero
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
| | - Kemal Demirer
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | | | - Randy B. Stockbridge
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA
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6
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Kim J, Fuller ME, Hatzinger PB, Chu KH. Isolation and characterization of nitroguanidine-degrading microorganisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169184. [PMID: 38092196 DOI: 10.1016/j.scitotenv.2023.169184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/05/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023]
Abstract
Nitroguanidine (NQ) is a component of newly developed insensitive munition (IM) formulations which are more resistant to impact, friction, heat, or sparks than conventional explosives. NQ is also used to synthesize various organic compounds and herbicides, and has both human and environmental health impacts. Despite the wide application and associated health concerns, limited information is known regarding NQ biodegradation, and only one NQ-degrading pure culture identified as Variovorax strain VC1 has been characterized. Here, we present results for three new NQ-degrading bacterial strains isolated from soil, sediment, and a lab-scale aerobic membrane bioreactor (MBR), respectively. Each of these strains -utilizes NQ as a nitrogen (N) source rather than as a source of carbon or energy. The MBR strain, identified as Pseudomonas extremaustralis strain NQ5, is capable of degrading NQ at a rate of approximately 150 μmole L-1 h-1 under aerobic conditions with glucose as a sole carbon source - and NQ as a sole N source. The addition of NH4+ to strain NQ5 during active growth with NQ as a sole N source slowed the growth rate for several hours, and the strain released NH4+, presumably from NQ. When NO3- was added as an alternate N source under similar conditions, the NO3- was not consumed, but NH4+ release into the culture medium was again observed. Strain NQ5 was also able to utilize guanylurea, guanidine, and ethyl allophanate as N sources, and - tolerate salt concentrations as high as 4 % (as NaCl). The other two stains, NQ4 and NQ7, both identified as Arthrobacter spp., grew significantly slower than strain NQ5 under similar culture conditions and tolerated only ∼1 % NaCl. In addition, neither strain NQ4 nor strain NQ7 was able to degrade guanlyurea or ethyl allophanate, but each degraded guanidine. These strains, particularly strain NQ5, may have practical applications for in-situ and ex-situ NQ bioremediation.
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Affiliation(s)
- Jinha Kim
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Mark E Fuller
- Aptim Federal Services, 17 Princess Road, Lawrenceville, NJ 08648, USA
| | - Paul B Hatzinger
- Aptim Federal Services, 17 Princess Road, Lawrenceville, NJ 08648, USA
| | - Kung-Hui Chu
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
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7
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Trostel L, Coll C, Fenner K, Hafner J. Combining predictive and analytical methods to elucidate pharmaceutical biotransformation in activated sludge. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:1322-1336. [PMID: 37539453 DOI: 10.1039/d3em00161j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
While man-made chemicals in the environment are ubiquitous and a potential threat to human health and ecosystem integrity, the environmental fate of chemical contaminants such as pharmaceuticals is often poorly understood. Biodegradation processes driven by microbial communities convert chemicals into transformation products (TPs) that may themselves have adverse ecological effects. The detection of TPs formed during biodegradation has been continuously improved thanks to the development of TP prediction algorithms and analytical workflows. Here, we contribute to this advance by (i) reviewing past applications of TP identification workflows, (ii) applying an updated workflow for TP prediction to 42 pharmaceuticals in biodegradation experiments with activated sludge, and (iii) benchmarking 5 different pathway prediction models, comprising 4 prediction models trained on different datasets provided by enviPath, and the state-of-the-art EAWAG pathway prediction system. Using the updated workflow, we could tentatively identify 79 transformation products for 31 pharmaceutical compounds. Compared to previous works, we have further automatized several steps that were previously performed by hand. By benchmarking the enviPath prediction system on experimental data, we demonstrate the usefulness of the pathway prediction tool to generate suspect lists for screening, and we propose new avenues to improve their accuracy. Moreover, we provide a well-documented workflow that can be (i) readily applied to detect transformation products in activated sludge and (ii) potentially extended to other environmental studies.
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Affiliation(s)
- Leo Trostel
- Department of Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, 8600, Zürich, Switzerland.
| | - Claudia Coll
- Department of Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, 8600, Zürich, Switzerland.
| | - Kathrin Fenner
- Department of Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, 8600, Zürich, Switzerland.
- Department of Chemistry, University of Zürich, 8057 Zürich, Switzerland
| | - Jasmin Hafner
- Department of Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, 8600, Zürich, Switzerland.
- Department of Chemistry, University of Zürich, 8057 Zürich, Switzerland
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8
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Li T, Xu ZJ, Zhou NY. Aerobic Degradation of the Antidiabetic Drug Metformin by Aminobacter sp. Strain NyZ550. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:1510-1519. [PMID: 36624085 DOI: 10.1021/acs.est.2c07669] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Metformin is becoming one of the most common emerging contaminants in surface and wastewater. Its biodegradation generally leads to the accumulation of guanylurea in the environment, but the microorganisms and mechanisms involved in this process remain elusive. Here, Aminobacter sp. strain NyZ550 was isolated and characterized for its ability to grow on metformin as a sole source of carbon, nitrogen, and energy under oxic conditions. This isolate also assimilated a variety of nitrogenous compounds, including dimethylamine. Hydrolysis of metformin by strain NyZ550 was accompanied by a stoichiometric accumulation of guanylurea as a dead-end product. Based on ion chromatography, gas chromatography-mass spectrometry, and comparative transcriptomic analyses, dimethylamine was identified as an additional hydrolytic product supporting the growth of the strain. Notably, a microbial mixture consisting of strain NyZ550 and an engineered Pseudomonas putida PaW340 expressing a guanylurea hydrolase was constructed for complete elimination of metformin and its persistent product guanylurea. Overall, our results not only provide new insights into the metformin biodegradation pathway, leading to the commonly observed accumulation of guanylurea in the environment, but also open doors for the complete degradation of the new pollutant metformin.
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Affiliation(s)
- Tao Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Zhi-Jing Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Ning-Yi Zhou
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240 Shanghai, China
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9
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Martinez-Vaz BM, Dodge AG, Lucero RM, Stockbridge RB, Robinson AA, Tassoulas LJ, Wackett LP. Wastewater bacteria remediating the pharmaceutical metformin: Genomes, plasmids and products. Front Bioeng Biotechnol 2022; 10:1086261. [PMID: 36588930 PMCID: PMC9800807 DOI: 10.3389/fbioe.2022.1086261] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022] Open
Abstract
Metformin is used globally to treat type II diabetes, has demonstrated anti-ageing and COVID mitigation effects and is a major anthropogenic pollutant to be bioremediated by wastewater treatment plants (WWTPs). Metformin is not adsorbed well by activated carbon and toxic N-chloro derivatives can form in chlorinated water. Most earlier studies on metformin biodegradation have used wastewater consortia and details of the genomes, relevant genes, metabolic products, and potential for horizontal gene transfer are lacking. Here, two metformin-biodegrading bacteria from a WWTP were isolated and their biodegradation characterized. Aminobacter sp. MET metabolized metformin stoichiometrically to guanylurea, an intermediate known to accumulate in some environments including WWTPs. Pseudomonas mendocina MET completely metabolized metformin and utilized all the nitrogen atoms for growth. Pseudomonas mendocina MET also metabolized metformin breakdown products sometimes observed in WWTPs: 1-N-methylbiguanide, biguanide, guanylurea, and guanidine. The genome of each bacterium was obtained. Genes involved in the transport of guanylurea in Aminobacter sp. MET were expressed heterologously and shown to serve as an antiporter to expel the toxic guanidinium compound. A novel guanylurea hydrolase enzyme was identified in Pseudomonas mendocina MET, purified, and characterized. The Aminobacter and Pseudomonas each contained one plasmid of 160 kb and 90 kb, respectively. In total, these studies are significant for the bioremediation of a major pollutant in WWTPs today.
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Affiliation(s)
- Betsy M. Martinez-Vaz
- Department of Biology and Biochemistry Program, Hamline University, St. Paul, MN, United States
| | - Anthony G. Dodge
- Department of Biochemistry, Molecular Biology and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
| | - Rachael M. Lucero
- Program in Chemical Biology and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Randy B. Stockbridge
- Program in Chemical Biology and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Ashley A. Robinson
- Department of Biology and Biochemistry Program, Hamline University, St. Paul, MN, United States
| | - Lambros J. Tassoulas
- Department of Biochemistry, Molecular Biology and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
| | - Lawrence P. Wackett
- Department of Biochemistry, Molecular Biology and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
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10
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Chaignaud P, Gruffaz C, Borreca A, Fouteau S, Kuhn L, Masbou J, Rouy Z, Hammann P, Imfeld G, Roche D, Vuilleumier S. A Methylotrophic Bacterium Growing with the Antidiabetic Drug Metformin as Its Sole Carbon, Nitrogen and Energy Source. Microorganisms 2022; 10:2302. [PMID: 36422372 PMCID: PMC9699525 DOI: 10.3390/microorganisms10112302] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 08/31/2023] Open
Abstract
Metformin is one of the most prescribed antidiabetic agents worldwide and is also considered for other therapeutic applications including cancer and endocrine disorders. It is largely unmetabolized by human enzymes and its presence in the environment has raised concern, with reported toxic effects on aquatic life and potentially also on humans. We report on the isolation and characterisation of strain MD1, an aerobic methylotrophic bacterium growing with metformin as its sole carbon, nitrogen and energy source. Strain MD1 degrades metformin into dimethylamine used for growth, and guanylurea as a side-product. Sequence analysis of its fully assembled genome showed its affiliation to Aminobacter niigataensis. Differential proteomics and transcriptomics, as well as mini-transposon mutagenesis of the strain, point to genes and proteins essential for growth with metformin and potentially associated with hydrolytic C-N cleavage of metformin or with cellular transport of metformin and guanylurea. The obtained results suggest the recent evolution of the growth-supporting capacity of strain MD1 to degrade metformin. Our results identify candidate proteins of the enzymatic system for metformin transformation in strain MD1 and will inform future research on the fate of metformin and its degradation products in the environment and in humans.
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Affiliation(s)
- Pauline Chaignaud
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156 CNRS, Université de Strasbourg, 67000 Strasbourg, France
| | - Christelle Gruffaz
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156 CNRS, Université de Strasbourg, 67000 Strasbourg, France
| | - Adrien Borreca
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156 CNRS, Université de Strasbourg, 67000 Strasbourg, France
- Institut Terre et Environnement de Strasbourg, UMR 7063 CNRS, ENGEES, Université de Strasbourg, 67000 Strasbourg, France
| | - Stéphanie Fouteau
- Génomique Métabolique, Genoscope, Institut de Biologie François Jacob, Commissariat à l’Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université d’Evry, Université Paris-Saclay, CEDEX, 91057 Evry, France
| | - Lauriane Kuhn
- Plateforme Protéomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, FR 1589 CNRS, CEDEX, 67084 Strasbourg, France
| | - Jérémy Masbou
- Institut Terre et Environnement de Strasbourg, UMR 7063 CNRS, ENGEES, Université de Strasbourg, 67000 Strasbourg, France
| | - Zoé Rouy
- Génomique Métabolique, Genoscope, Institut de Biologie François Jacob, Commissariat à l’Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université d’Evry, Université Paris-Saclay, CEDEX, 91057 Evry, France
| | - Philippe Hammann
- Plateforme Protéomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, FR 1589 CNRS, CEDEX, 67084 Strasbourg, France
| | - Gwenaël Imfeld
- Institut Terre et Environnement de Strasbourg, UMR 7063 CNRS, ENGEES, Université de Strasbourg, 67000 Strasbourg, France
| | - David Roche
- Génomique Métabolique, Genoscope, Institut de Biologie François Jacob, Commissariat à l’Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université d’Evry, Université Paris-Saclay, CEDEX, 91057 Evry, France
| | - Stéphane Vuilleumier
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156 CNRS, Université de Strasbourg, 67000 Strasbourg, France
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11
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He Y, Zhang Y, Ju F. Metformin Contamination in Global Waters: Biotic and Abiotic Transformation, Byproduct Generation and Toxicity, and Evaluation as a Pharmaceutical Indicator. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13528-13545. [PMID: 36107956 DOI: 10.1021/acs.est.2c02495] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metformin is the first-line antidiabetic drug and one of the most prescribed medications worldwide. Because of its ubiquitous occurrence in global waters and demonstrated ecotoxicity, metformin, as with other pharmaceuticals, has become a concerning emerging contaminant. Metformin is subject to transformation, producing numerous problematic transformation byproducts (TPs). The occurrence, removal, and toxicity of metformin have been continually reviewed; yet, a comprehensive analysis of its transformation pathways, byproduct generation, and the associated change in adverse effects is lacking. In this review, we provide a critical overview of the transformation fate of metformin during water treatments and natural processes and compile the 32 organic TPs generated from biotic and abiotic pathways. These TPs occur in aquatic systems worldwide along with metformin. Enhanced toxicity of several TPs compared to metformin has been demonstrated through organism tests and necessitates the development of complete mineralization techniques for metformin and more attention on TP monitoring. We also assess the potential of metformin to indicate overall contamination of pharmaceuticals in aquatic environments, and compared to the previously acknowledged ones, metformin is found to be a more robust or comparable indicator of such overall pharmaceutical contamination. In addition, we provide insightful avenues for future research on metformin.
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Affiliation(s)
- Yuanzhen He
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024, China
| | - Yanyan Zhang
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024, China
| | - Feng Ju
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024, China
- Research Center for Industries of the Future (RCIF), School of Engineering, Westlake University, Hangzhou 310030, China
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, China
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Burata OE, Yeh TJ, Macdonald CB, Stockbridge RB. Still rocking in the structural era: A molecular overview of the small multidrug resistance (SMR) transporter family. J Biol Chem 2022; 298:102482. [PMID: 36100040 PMCID: PMC9574504 DOI: 10.1016/j.jbc.2022.102482] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/24/2022] [Accepted: 09/07/2022] [Indexed: 11/20/2022] Open
Abstract
The small multidrug resistance (SMR) family is composed of widespread microbial membrane proteins that fulfill different transport functions. Four functional SMR subtypes have been identified, which variously transport the small, charged metabolite guanidinium, bulky hydrophobic drugs and antiseptics, polyamines, and glycolipids across the membrane bilayer. The transporters possess a minimalist architecture, with ∼100-residue subunits that require assembly into homodimers or heterodimers for transport. In part because of their simple construction, the SMRs are a tractable system for biochemical and biophysical analysis. Studies of SMR transporters over the last 25 years have yielded deep insights for diverse fields, including membrane protein topology and evolution, mechanisms of membrane transport, and bacterial multidrug resistance. Here, we review recent advances in understanding the structures and functions of SMR transporters. New molecular structures of SMRs representing two of the four functional subtypes reveal the conserved structural features that have permitted the emergence of disparate substrate transport functions in the SMR family and illuminate structural similarities with a distantly related membrane transporter family, SLC35/DMT.
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Affiliation(s)
- Olive E Burata
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Trevor Justin Yeh
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Randy B Stockbridge
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA; Program in Biophysics, University of Michigan, Ann Arbor, Michigan, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA.
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13
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Pérez-Benítez A, Ariza-Ramírez JL, Fortis-Valera M, Arroyo-Carmona RE, Martínez de la Luz MI, Ramírez-Contreras D, Bernès S. Bis{[amino(iminiumyl)methyl]urea} tetrakis{2-[(dimethylamino)(iminiumyl)methyl]guanidine} di-μ 6-oxido-tetra-μ 3-oxido-tetradeca-μ 2-oxido-octaoxidodecavanadium(V) tetrahydrate. IUCRDATA 2022; 7:x220627. [PMID: 36339897 PMCID: PMC9462036 DOI: 10.1107/s2414314622006277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 06/14/2022] [Indexed: 11/23/2022] Open
Abstract
In the crystal structure of the title compound, numerous N—H⋯O and O—H⋯O hydrogen bonds of medium strengths connect metforminium and guanylurea cations and centrosymmetric decavanadate(V) anions into a three-dimensional network structure. The title compound, (C4H12N5)4(C2H7N4O)2[V10O28]·4H2O, is a by-product obtained by reacting ammonium metavanadate(V), metformin hydrochloride and acetic acid in the presence of sodium hypochlorite, at pH = 5. The crystal structure comprises a decavanadate(V) anion (V10O28)6– lying on an inversion centre in space group P, while cations and solvent water molecules are placed in general positions, surrounding the anion, and forming numerous N—H⋯O and O—H⋯O hydrogen bonds. Metforminium (C4H12N5)+ and guanylurea (C2H7N4O)+ cations display the expected shape. Interestingly, in physiology the latter cation is known to be the main metabolite of the former one. The reported structure thus supports the role of sodium hypochlorite as an oxidizing reagent being able to degrade metformin hydrochloride to form guanylurea.![]()
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