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electrobiocorrosion by microbes without outer-surface cytochromes

mLife 2024年第1期3卷 110-118页

作者： dawn e.holmes Trevor L.Woodard Jessica A.Smith Florin Musat Derek R.Lovley Department of Microbiology University of Massachusetts AmherstAmherstMassachusettsUSA Department of Physical and Biological Science Western New England UniversitySpringfieldMassachusettsUSA Department of Biomolecular Sciences Central Connecticut State UniversityNew BritainConnecticutUSA Department of Biology Section for MicrobiologyAarhus UniversityAarhusDenmark Department of Molecular Biology and Biotechnology Facuity of Biology and GeologyBabes-Bolyai UniversityCluj-NapocaRomania

Anaerobic microbial corrosion of iron-containing metals causes extensive economic damage.Some microbes are capable of direct metal-to-microbe electron transfer(electrobiocorrosion),but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation.Previous studies have suggested that respiration with 316L stainless steel as the electron donor is indicative of electrobiocorrosion,because,unlike pure Fe^(0),316L stainless steel does not abiotically generate H2 as an intermediary electron carrier.Here,we report that all of the methanogens(Methanosarcina vacuolata,Methanothrix soehngenii,and Methanobacterium strain IM1)and acetogens(Sporomusa ovata and Clostridium ljungdahli)evaluated respired with pure Fe^(0)as the electron donor,but only M.vacuolata,Mx.soehngeni,and S.ovata were capable of stainless steel electrobiocorrosion.The electrobiocorrosive methanogens re-quired acetate as an additional energy source in order to produce methane from stainless steel.Cocultures of S.ovata and Mx.soehngeni demonstrated how acetogens can provide acetate to methanogens during corrosion.Not only was Meth-anobacterium strain IM1 not capable of electrobiocorrosion,but it also did not accept electrons from Geobacter metal-lireducens,an effective electron-donating partner for direct interspecies electron transfer to all methanogens that can directly accept electrons from Fe^(0).The finding that M.vacuolata,Mx.soehngeni,and S.ovata are capable of electrobiocorrosion,despite a lack of the outer-surface c-type cytochromes previously found to be important in other electrobiocorrosive microbes,demonstrates that there are multiple microbial strategies for making electrical contact with Fe^(0).

关键词： acetogen corrosion Fe^(0) methanogen stainless steel

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Different outer membrane c‐type cytochromes are involved in direct interspecies electron transfer to Geobacter or Methanosarcina species

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mLife 2022年第3期1卷 272-286页

作者： dawn e.holmes Jinjie Zhou Jessica A.Smith Caiqin Wang Xinying Liu Derek R.Lovley Department of Microbiology University of Massachusetts‐AmherstAmherstMassachusettsUSA Department of Physical and Biological Science Western New England UniversitySpringfieldMassachusettsUSA Institute for Advanced Study Shenzhen UniversityShenzhenChina Department of Biomolecular Sciences Central Connecticut State UniversityNew BritainConnecticutUSA College of environment Zhejiang University of TechnologyHangzhouChina College of environmental Science and engineering Beijing Forestry UniversityBeijingChina.

Direct interspecies electron transfer(DIeT)may be most important in methanogenic environments,but mechanistic studies of DIeT to date have primarily focused on cocultures in which fumarate was the terminal electron acceptor.To better understand DIeT with methanogens,the transcriptome of Geobacter metallireducens during DIeT‐based growth with G.sulfurreducens reducing fumarate was compared with G.metallireducens grown in coculture with diverse Methanosarcina.The transcriptome of G.metallireducens cocultured with G.sulfurreducens was significantly different from those with Methanosarcina.Furthermore,the transcriptome of G.metallireducens grown with Methanosarcina barkeri,which lacks outer‐surface c‐type cytochromes,differed from those of G.metallireducens cocultured with M.acetivorans or M.subterranea,which have an outer‐surface c‐type cytochrome that serves as an electrical connect for DIeT.Differences in G.metallireducens expression patterns for genes involved in extracellular electron transfer were particularly notable.Cocultures with c‐type cytochrome deletion mutant strains,ΔGmet_0930,ΔGmet_0557 andΔGmet_2896,never became established with G.sulfurreducens but adapted to grow with all three Methanosarcina.Two porin–cytochrome complexes,PccF and PccG,were important for DIeT;however,PccG was more important for growth with Methanosarcina.Unlike cocultures with G.sulfurreducens and M.acetivorans,electrically conductive pili were not needed for growth with M.barkeri.Shewanella oneidensis,another electroactive microbe with abundant outer‐surface c‐type cytochromes,did not grow via DIeT.The results demonstrate that the presence of outer‐surface c‐type cytochromes does not necessarily confer the capacity for DIeT and emphasize the impact of the electron‐accepting partner on the physiology of the electron‐donating DIeT partner.

关键词： c‐type cytochrome direct interspecies electron transfer(DIeT) extracellular electron transfer Geobacter Methanosarcina

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Cytochrome-mediated direct electron uptake from metallic iron by Methanosarcina acetivorans

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mLife 2022年第4期1卷 443-447页

作者： dawn e.holmes Haiyan Tang Trevor Woodard Dandan Liang Jinjie Zhou Xinying Liu Derek R.Lovley Department of Microbiology University of Massachusetts-AmherstAmherstMassachusettsUSA Department of Physical and Biological Science Western New England UniversitySpringfieldMassachusettsUSA Jiangsu Provincial Key Lab of Solid Organic Waste Utilization Jiangsu Collaborative Innovation Center of Solid Organic WastesEducational Ministry Engineering Center of Resource-saving FertilizersNanjing Agricultural UniversityNanjingChina State Key Laboratory of Urban Water Resource and environment School of EnvironmentHarbin Institute of TechnologyHarbinChina Institute for Advanced Study Shenzhen UniversityShenzhenGuangdongChina College of environmental Science and engineering Beijing Forestry UniversityBeijingChina

Impact statement Methane-producing microorganisms accelerate the corrosion of iron-containing metals.Previous studies have inferred that some methanogens might directly accept electrons from Fe(0),but when this possibility was more intensively investigated,H2 was shown to be an intermediary electron carrier between Fe(0)and methanogens.Here,we report that Methanosarcina acetivorans catalyzes direct metal-to-microbe electron transfer to support methane production.Deletion of the gene for the multiheme,outer-surface c-type cytochrome MmcA eliminated methane production from Fe(0),consistent with the key role of MmcA in other forms of extracellular electron exchange.These findings,coupled with the previous demonstration that outer-surface c-type cytochromes are also electrical contacts for electron uptake from Fe(0)by Geobacter and Shewanella species,suggest that the presence of multiheme c-type cytochromes on corrosion surfaces might be diagnostic for direct metal-to-microbe electron transfer and that interfering with cytochrome function might be a strategy to mitigate corrosion.

关键词： corrosion electron outer

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Development of a whole-cell biosensor based on an ArsR-Pars regulatory circuit from Geobacter sulfurreducens

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environmental Science and ecotechnology 2021年第2期6卷 3-10页

作者： Pengsong Li Yumingzi Wang Xin Yuan Xinying Liu Chunmao Liu Xiaofen Fu Dezhi Sun Yan Dang dawn e.holmes Beijing Key Laboratory for Source Control Technology of Water Pollution Engineering Research Center for Water Pollution Source Control and EcoremediationCollege of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Key Laboratory of Beijing Yanjing Beer Brewing Technology Beijing Yan Jing Brewery Company Ltd.Beijing 101300China MOST-USDA Joint Research Center for Biofuels Beijing Engineering Research Center for BiofuelsInstitute of New Energy TechnologyTsinghua UniversityBeijing 100084China Department of Physical and Biological Sciences Western New England University1215 Wilbraham RdSpringfieldMA 01119USA

In this study,an escherichia coli(e.coli)whole-cell biosensor for the specific detection of bioavailable arsenic was developed by placing a green fluorescent protein(GFP)reporter gene under the control of the ArsR1(GSU2952)regulatory circuit from Geobacter sulfurreducens.e.coli cells only emitted green fluorescence in the presence of arsenite and were more sensitive to arsenite when they were grown in M9 supplemented medium compared to LB medium.Under optimal test conditions,the Geobacter arsR1 promoter had a detection limit of 0.01 mM arsenite and the GFP expression was linear within a range of 0.03-0.1 mM(2.25-7.5 mg/l).These values were well below World Health Organization’s drinking water quality standard,which is 10 mg/l.The feasibility of using this whole-cell biosensor to detect arsenic in water samples,such as arsenic polluted tap water and landfill leachate was verified.The biosensor was determined to be just as sensitive as atomic fluorescence spectrometry.This study examines the potential applications of biosensors constructed with Geobacter ArsR-Pars regulatory circuits and provides a rapid and cost-effective tool that can be used for arsenic detection in water samples.

关键词： Arsenic detection Whole-cell biosensor Geobacter sulfurreducens ars operon

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Nonuniform Dependence on the Initial Data for Solutions of Conservation Laws

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Communications on Applied Mathematics and Computation 2024年第1期6卷 489-500页

作者： John M.holmes Barbara Lee Keyfitz Department of Mathematics The Ohio State UniversityColumbusOH43210USA

In this paper,we study systems of conservation laws in one space dimension.We prove that for classical solutions in Sobolev spaces H^(s),with s>3/2,the data-to-solution map is not uniformly continuous.Our results appl... 详细信息

关键词： Conservation laws Data-to-solution map Nonuniform dependence

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Association of daily sitting time and leisure-time physical activity with body fat among U.S.adults

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Journal of Sport and Health Science 2024年第2期13卷 195-203页

作者： Jingwen Liao Min Hu Kellie Imm Clifton J.holmes Jie Zhu Chao Cao Lin Yang Guangdong Provincial Key Laboratory of Physical Activity and Health Promotion Guangzhou Sport UniversityGuangzhou 510500China Scientific Research Center Guangzhou Sport UniversityGuangzhou 510500China Division of epidemiology&Genetics Department of Population and Public Health SciencesKeck School of Medicine of the University of Southern CaliforniaLos AngelesCA 90033USA Program in Physical Therapy Washington University School of MedicineSt.LouisMO 63110USA Center for Human Nutrition Washington University School of MedicineSt.LouisMO 63110USA Department of Plastic and Reconstructive Surgery Shanghai East HospitalTongji UniversityShanghai 200070China Department of Cancer epidemiology and Prevention Research Alberta Health ServicesCalgary T2S 3C3Canada Department of Oncology and Community Health Sciences University of CalgaryCalgary T2N 1N4Canada

Background:Prolonged sitting and reduced physical activity lead to low energy expenditures.However,little is known about the joint impact of daily sitting time and physical activity on body fat distribution.We investigated the independent and joint associations of daily sitting time and physical activity with body fat among adults.Methods:This was a cross-sectional analysis of U.S.nationally representative data from the National Health and Nutrition examination Survey2011-2018 among adults aged 20 years or older.Daily sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity Questionnaire.Body fat(total and trunk fat percentage)was determined via dual X-ray absorptiometry.Results:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past week.After fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both sexes.When stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently active.In the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/day.Conclusion:Prolonged daily sitting time was associated with increased body fat among U.S.adults.The higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

关键词： Adults Body fat distribution Physical activity Sitting time

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Thermal stability of the Cr-coated zirconium alloy microstructure prepared by pulsed laser deposition

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Tungsten 2024年第2期6卷 333-341页

作者： Bo Li Hui-Long Yang Reuben holmes Li-Juan Cui Sho Kano Hiroaki Abe Department of Nuclear engineering and Management The University of TokyoTokyo 113-8656Japan School of Nuclear Science and engineering Shanghai Jiao Tong UniversityShanghai 200240China Nuclear Professional School The University of TokyoIbaraki 319-1188Japan

Cr-coated zirconium alloy was prepared by pulsed laser deposition(PLD)for the application of accident-tolerant fuel cladding in light water reactors.The microstructural characteristics of the Cr coating and its evolution with temperature were investigated using grazing incidence X-ray diff raction and in situ heating transmission electron microscopy(TeM).Results show that the microstructure of the laser-deposited Cr coatings consists mainly of fine and non-specific shaped nano-crystals in the inner layer and columnar crystals in the outer layer.The recrystallization of the Cr-coating layer starts at 300–400℃ to release the high strain introduced by PLD,and the grain coalescence starts at temperatures>400°C.Upon annealing,the(110)-texture gradually intensifi es because of its high reticular density and low close-packed energy.Additionally,in situ heating TeM observation shows the presence of cavities on the Cr–Zr interface,which may result from the interdiff usion and/or the transformation from amorphous to crystalline.

关键词： Accident tolerant fuel Crcoating Interface Microstructure Pulsed laser deposition

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Commentary on "Association of daily sitting time and leisure-time physical activity with body fat among U.S.adults"

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Journal of Sport and Health Science 2024年第2期13卷 127-129页

作者： Barbara e.Ainsworth School of exercise and Health Shanghai University of SportShanghai 200438China

In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and examination Survey to examine associations between h/day sitting,meeting (or not meeting) the U.S.Physical Activity Guidelines of≥150 min/week of moderate-and vigorous-intensity LTPA,and combinations of sitting time and LTPA on totaland trunk percent body fat (BF%).

关键词： U.S. adult among

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Advances in spinal cord injury:insights from non-human primates

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Neural Regeneration Research 2024年第11期19卷 2354-2364页

作者： Gaetan Poulen Florence e.Perrin University of Montpellier INSERMEPHEMontpellierFrance Department of Neurosurgery Gui de Chauliac HospitalMontpellier University Medical CenterMontpellierFrance Institut Universitaire de France(IUF) ParisFrance

Spinal cord injury results in significant sensorimotor deficits,currently,there is no curative treatment for the symptoms induced by spinal cord injury.Basic and pre-clinical research on spinal cord injury relies on the development and characterization of appropriate animal models.These models should replicate the symptoms observed in human,allowing for the exploration of functional deficits and investigation into various aspects of physiopathology of spinal cord injury.Non-human primates,due to their close phylogenetic association with humans,share more neuroanatomical,genetic,and physiological similarities with humans than rodents.Therefore,the responses to spinal cord injury in nonhuman primates most likely resemble the responses to traumatism in humans.In this review,we will discuss nonhuman primate models of spinal cord injury,focusing on in vivo assessments,including behavioral tests,magnetic resonance imaging,and electrical activity recordings,as well as ex vivo histological analyses.Additionally,we will present therapeutic strategies developed in non-human primates and discuss the unique specificities of non-human primate models of spinal cord injury.

关键词： behavior cellular analysis non-human primates spinal cord injury tissue analysis

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event-triggered H_(∞) consensus control for input-constrained multi-agent systems via reinforcement learning

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Control Theory and Technology 2024年第1期22卷 25-38页

作者： Jinxuan Zhang Chang-e Ren College of Information engineering Capital Normal UniversityBeijing100089China

This article presents an event-triggered H_(∞) consensus control scheme using reinforcement learning (RL) for nonlinear second-order multi-agent systems (MASs) with control constraints. First, considering control constraints, the constrained H_(∞) consensus problem is transformed into a multi-player zero-sum game with non-quadratic performance functions. Then, an event-triggered control method is presented to conserve communication resources and a new triggering condition is developed for each agent to make the triggering threshold independent of the disturbance attenuation level. To derive the optimal controller that can minimize the cost function in the case of worst disturbance, a constrained Hamilton–Jacobi–Bellman (HJB) equation is defined. Since it is difficult to solve analytically due to its strongly non-linearity, reinforcement learning (RL) is implemented to obtain the optimal controller. In specific, the optimal performance function and the worst-case disturbance are approximated by a time-triggered critic network;meanwhile, the optimal controller is approximated by event-triggered actor network. After that, Lyapunov analysis is utilized to prove the uniformly ultimately bounded (UUB) stability of the system and that the network weight errors are UUB. Finally, a simulation example is utilized to demonstrate the effectiveness of the control strategy provided.

关键词： H_(∞)optimal control Input constrains Multi-agent systems(MASs) Reinforcement learning(RL)

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