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1.
mBio ; : e0058024, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39092920

RESUMO

To investigate their roles in extracellular electron transfer (EET), the porin-cytochrome (pcc) gene clusters Gmet0825-0828, Gmet0908-0910, and Gmet0911-0913 of the Gram-negative bacterium Geobacter metallireducens were deleted. Failure to delete all pcc gene clusters at the same time suggested their essential roles in extracellular reduction of Fe(III)-citrate by G. metallireducens. Deletion of Gmet0825-0828 had no impact on bacterial reduction of Fe(III)-citrate but diminished bacterial reduction of ferrihydrite and abolished anode reduction and direct interspecies electron transfer (DIET) to Methanosarcina barkeri and Geobacter sulfurreducens. Although it had no impact on the bacterial reduction of Fe(III)-citrate, deletion of Gmet0908-0910 delayed ferrihydrite reduction, abolished anode reduction, and diminished DIET. Deletion of Gmet0911-0913 had little impact on DIET but diminished bacterial reductions of Fe(III)-citrate, ferrihydrite, and anodes. Most importantly, deletions of both Gmet0825-0828 and Gmet0908-0910 restored bacterial reduction of ferrihydrite and anodes and DIET. Enhanced expression of Gmet0911-0913 in this double mutant when grown in coculture with G. sulfurreducens ΔhybLΔfdnG suggested that this cluster might compensate for impaired EET functions of deleting Gmet0825-0828 and Gmet0908-0910. Thus, these pcc gene clusters played essential, distinct, overlapping, and compensatory roles in EET of G. metallireducens that are difficult to characterize as deletion of some clusters affected expression of others. The robustness of these pcc gene clusters enabled G. metallireducens to mediate EET to different acceptors for anaerobic growth even when two of its three pcc gene clusters were inactivated by mutation. The results from this investigation provide new insights into the roles of pcc gene clusters in bacterial EET. IMPORTANCE: The Gram-negative bacterium Geobacter metallireducens is of environmental and biotechnological significance. Crucial to the unique physiology of G. metallireducens is its extracellular electron transfer (EET) capability. This investigation sheds new light on the robust roles of the three porin-cytochrome (pcc) gene clusters, which are directly involved in EET across the bacterial outer membrane, in the EET of G. metallireducens. In addition to their essential roles, these gene clusters also play distinct, overlapping, and compensatory roles in the EET of G. metallireducens. The distinct roles of the pcc gene clusters enable G. metallireducens to mediate EET to a diverse group of electron acceptors for anaerobic respirations. The overlapping and compensatory roles of the pcc gene clusters enable G. metallireducens to maintain and restore its EET capability for anaerobic growth when one or two of its three pcc gene clusters are deleted from the genome.

2.
Appl Environ Microbiol ; 90(8): e0085024, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39016614

RESUMO

Viral communities exist in a variety of ecosystems and play significant roles in mediating biogeochemical processes, whereas viruses inhabiting strongly alkaline geochemical systems remain underexplored. In this study, the viral diversity, potential functionalities, and virus-host interactions in a strongly alkaline environment (pH = 10.4-12.4) exposed to the leachates derived from the serpentinization-like reactions of smelting slags were investigated. The viral populations (e.g., Herelleviridae, Queuovirinae, and Inoviridae) were closely associated with the dominating prokaryotic hosts (e.g., Meiothermus, Trueperaceae, and Serpentinomonas) in this ultrabasic environment. Auxiliary metabolic genes (AMGs) suggested that viruses may enhance hosts' fitness by facilitating cofactor biosynthesis, hydrogen metabolism, and carbon cycling. To evaluate the activity of synthesis of essential cofactor vitamin B9 by the viruses, a viral folA (vfolA) gene encoding dihydrofolate reductase (DHFR) was introduced into a thymidine-auxotrophic strain Escherichia coli MG1655 ΔfolA mutant, which restored the growth of the latter in the absence of thymidine. Notably, the homologs of the validated vDHFR were globally distributed in the viromes across various ecosystems. The present study sheds new light on the unique viral communities in hyperalkaline ecosystems and their potential beneficial impacts on the coexisting microbial consortia by supplying essential cofactors. IMPORTANCE: This study presents a comprehensive investigation into the diversity, potential functionalities, and virus-microbe interactions in an artificially induced strongly alkaline environment. Functional validation of the detected viral folA genes encoding dihydrofolate reductase substantiated the synthesis of essential cofactors by viruses, which may be ubiquitous, considering the broad distribution of the viral genes associated with folate cycling.


Assuntos
Microbiota , Concentração de Íons de Hidrogênio , Viroma/genética , Vírus/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Tetra-Hidrofolato Desidrogenase/genética , Tetra-Hidrofolato Desidrogenase/metabolismo , Bactérias/genética , Bactérias/metabolismo , Bactérias/classificação
3.
Microbiol Spectr ; 12(8): e0051224, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-38916364

RESUMO

Extracellular iodate reduction by Shewanella spp. contributes to iodide generation in the biogeochemical cycling of iodine. However, there is a disagreement on whether Shewanella spp. use different extracellular electron transfer pathways with dependence on electron donors in iodate reduction. In this study, a series of gene deletion mutants of Shewanella oneidensis MR-1 were created to investigate the roles of dmsEFABGH, mtrCAB, and so4357-so4362 operons in iodate reduction. The iodate-reducing activity of the mutants was tested with lactate, formate, and H2 as the sole electron donors, respectively. In the absence of single-dms gene, iodate reduction efficiency of the mutants was only 12.9%-84.0% with lactate at 24 hours, 22.1%-85.9% with formate at 20 hours, and 19.6%-57.7% with H2 at 42 hours in comparison to complete reduction by the wild type. Progressive inhibition of iodate reduction was observed when the dms homolog from the so4357-so4362 operon was deleted in the single-dms gene mutants. This result revealed complementation of dmsEFABGH by so4357-so4362 at the single-gene level, indicating modularity of the extracellular electron transfer pathway encoded by dmsEFABGH operon. Under the conditions of all electron donors, significant inhibition of iodate reduction and accumulation of H2O2 were detected for ΔmtrCAB. Collectively, these results demonstrated that the dmsEFABGH operon encodes an essential and modular iodate-reducing pathway without electron donor dependence in S. oneidensis MR-1. The mtrCAB operon was involved in H2O2 elimination with all electron donors. The findings in this study improved the understanding of molecular mechanisms underlying extracellular iodate reduction.IMPORTANCEIodine is an essential trace element for human and animals. Recent studies revealed the contribution of microbial extracellular reduction of iodate in biogeochemical cycling of iodine. Multiple reduced substances can be utilized by microorganisms as energy source for iodate reduction. However, varied electron transfer pathways were proposed for iodate reduction with different electron donors in the model strain Shewanella oneidensis MR-1. Here, through a series of gene deletion and iodate reduction experiments, we discovered that the dmsEFABGH operon was essential for iodate reduction with at least three electron donors, including lactate, formate, and H2. The so4357-so4362 operon was first demonstrated to be capable of complementing the function of dmsEFABGH at single-gene level.


Assuntos
Proteínas de Bactérias , Iodatos , Óperon , Oxirredução , Shewanella , Shewanella/genética , Shewanella/metabolismo , Transporte de Elétrons , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Iodatos/metabolismo , Formiatos/metabolismo , Deleção de Genes
4.
Artigo em Inglês | MEDLINE | ID: mdl-38913036

RESUMO

A novel chemoheterotrophic iron-reducing micro-organism, designated as strain LSZ-M11000T, was isolated from sediment of the Marianas Trench. Phylogenetic analysis based on the 16S rRNA gene revealed that strain LSZ-M11000T belonged to genus Tepidibacillus, with 97 % identity to that of Tepidibacillus fermentans STGHT, a mesophilic bacterium isolated from the Severo-Stavropolskoye underground gas storage facility in Russia. The polar lipid profile of strain LSZ-M11000T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, as well as other unidentified phospholipids and lipids. The major fatty acids were C16 : 0 (28.4 %), C18 : 0 (15.8 %), iso-C15 : 0 (12.9 %), and anteiso-C15 : 0 (12.0 %). Strain LSZ-M11000T had no menaquinone. Genome sequencing revealed that the genome size of strain LSZ-M11000T was 2.97 Mb and the DNA G+C content was 37.9 mol%. The average nucleotide identity values between strain LSZ-M11000T and its close phylogenetic relatives, Tepidibacillus fermentans STGHT and Tepidibacillus decaturensis Z9T, were 76.4 and 72.6 %, respectively. The corresponding DNA-DNA hybridization estimates were 20.9 and 23.4 %, respectively. Cells of strain LSZ-M11000T were rod-shaped (1.0-1.5×0.3-0.5 µm). Using pyruvate as an electron donor, it was capable of reducing KMnO4, MnO2, As(V), NaNO3, NaNO2, Na2SO4, Na2S2O3, and K2Cr2O7. Based on phenotypic, genotypic, and phylogenetic evidence, strain LSZ-M11000T is proposed to be a novel strain of the genus Tepidibacillus, for which the name Tepdibacillus marianensis is proposed. The type strain is LSZ-M11000T (=CCAM 1008T=JCM 39431T).


Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Ácidos Graxos , Sedimentos Geológicos , Ferro , Fosfolipídeos , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , RNA Ribossômico 16S/genética , Sedimentos Geológicos/microbiologia , DNA Bacteriano/genética , Federação Russa , Ferro/metabolismo , Processos Heterotróficos , Hibridização de Ácido Nucleico , Bacillaceae/classificação , Bacillaceae/genética , Bacillaceae/isolamento & purificação , Sequenciamento Completo do Genoma , Oxirredução
5.
Front Nutr ; 11: 1386646, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38746935

RESUMO

Background: Observational studies have shown that micronutrients can affect the occurrence of frailty. However, it is not clear whether there is a causal relationship between the two. This study aimed to explore the causal relationship between circulating micronutrient levels and frailty risk using a two-sample Mendelian randomization (TSMR) approach. Methods: We gathered and screened instrumental variables (IVs) for six circulating micronutrients, including vitamin B12, vitamin B6, folate, vitamin C, vitamin D, and vitamin E, from published genome-wide association studies (GWAS) and the IEU OpenGWAS open database. Summary statistics for frailty were obtained from a GWAS meta-analysis, including the UK Biobank and TwinGene (N = 175,226). We performed two independent TSMR analyses and a meta-analysis based on the two independent MR estimates to assess the causal relationship between circulating micronutrientn and frailty. Results: Our study found, no causal relationship between genetically predicted vitamin D (ß = -0.059, p = 0.35), vitamin B6 (ß = 0.006, p = 0.80), vitamin E (ß = -0.011, p = 0.79), vitamin C (ß = -0.044, p = 0.06), vitamin B12 (ß = -0.027, p = 0.37), and folate (ß = 0.029, p = 0.17), with frailty. Conclusion: This study showed that these six micronutrients did not reduce the risk of developing frailty. However, we think it is necessary further to investigate the relationship and mechanisms between micronutrients and frailty using methods such as randomized controlled trials.

6.
Noncoding RNA Res ; 9(3): 667-677, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38577016

RESUMO

Lung cancer (LC) is considered to have the highest mortality rate around the world. Because there are no early diagnostic signs or efficient clinical alternatives, distal metastasis and increasing numbers of recurrences are a challenge in the clinical management of LC. Long non-coding RNAs (lncRNAs) have recently been recognized as a critical regulator involved in the progression and treatment response to LC. The Wnt/ß-catenin pathway has been shown to influence LC occurrence and progress. Therefore, discovering connections between Wnt signaling pathway and lncRNAs may offer new therapeutic targets for improving LC treatment and management. In this review, the purpose of this article is to present possible therapeutic approaches by reviewing particular relationships, key processes, and molecules associated to the beginning and development of LC.

7.
Infect Drug Resist ; 17: 1041-1049, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38511153

RESUMO

Purpose: This study aimed to investigate awareness of tuberculosis control among post-treatment tuberculosis patients, in order to provide a basis for future preventive and control work in this population. Patients and Methods: A cross-sectional descriptive study was conducted on post-treatment patients with tuberculosis in seven districts of Jinan City between July 2021 and December 2022. A face-to-face or telephone interviews using structured questionnaires for the research subjects were conducted by data collectors. Analyses were carried out first for all subjects, and then separately for male and female subjects. Results: A total of 837 valid questionnaires were collected, of which 495 were males and 342 were females. The awareness rate of the core TB knowledge was 82.46%. The ≥65 year group in the total group (OR=0.43, 95% CI: (0.28, 0.68)), male (OR=0.47, 95% CI: (0.27, 0.83)) and female group (OR=0.40, 95% CI: (0.19, 0.86)) was lower than that of the control group. Educational level and monthly income are the main factors of TB cognition in total group. People with university or higher education (OR=2.05, 95% CI: (1.38, 3.05)) and with a monthly income of ≥6,000 (OR=1.89, 95% CI: (1.10, 3.25)) had a higher awareness rate. The group with current residence in the city was more aware than the reference group. Conclusion: In the future, the communication of the main transmission route, suspicious symptoms, and cure of TB needs to be strengthened for the post-treatment TB patients. The elderly, those with secondary school education or below, agricultural workers and low-income people are the groups with weak knowledge of TB, and they are also the groups that need to be focused on health education. The above information should be focused on the above groups of people in order to educate them in a way that is easily acceptable to them.

8.
Artigo em Inglês | MEDLINE | ID: mdl-38366876

RESUMO

Sarcopenia is among the most common musculoskeletal illnesses, yet its underlying biochemical mechanisms remain incompletely understood. In this study, we used Mendelian randomization (MR) to investigate the causal relationship between the genetically determined blood metabolites and sarcopenia, with the overall objective of identifying likely molecular pathways for sarcopenia. We used 2-sample MR to investigate the effects of blood metabolites on sarcopenia-related traits. 452 metabolites were exposure, and 3 sarcopenia-related traits as the outcomes: handgrip strength, appendicular lean mass, and walking pace. The inverse-variance weighted (IVW) causal estimates were determined. For sensitivity analysis, methods such as MR-Egger regression, the weighted median, the weighted mode, and the heterogeneity test were used. Additionally, for complementation, we performed replication, meta-analysis, and metabolic pathway analyses. Candidate biomarkers were defined by meeting one of the following criteria: (1) significant metabolites are defined as pIVW < pBonferroni [1.11 × 10-4 (.05/452)]; (2) strong metabolites are defined as 4 MR methods p < .05; and (3) suggestive metabolites are defined as passing sensitivity analysis. Three metabolites (creatine, 1-arachidonoylglycerophosphocholine, and pentadecanoate [15:0]) with significant causality, 3 metabolites (glycine, 1-arachidonoylglycerophosphocholine, and epiandrosterone sulfate) with strong causality, and 25 metabolites (including leucylleucin, pyruvic acid, etc.) with suggestive causality were associated with sarcopenia-related traits. After further replication analyses and meta-analysis, these metabolites maintained substantial effects on sarcopenia-related traits. We additionally identified 14 important sarcopenia-related trait metabolic pathways. By combining metabolomics with genomics, these candidate metabolites and metabolic pathways identified in our study may provide new clues regarding the mechanisms underlying sarcopenia.


Assuntos
Força da Mão , Sarcopenia , Humanos , Análise da Randomização Mendeliana , Sarcopenia/genética , Metaboloma , Fenótipo , Estudo de Associação Genômica Ampla
9.
BMJ Open ; 14(1): e077799, 2024 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-38286706

RESUMO

INTRODUCTION: Neuropsychiatric distubance is a common clinical manifestation in acute ischemic stroke. However, it is frequently overlooked by clinicians. This study aimed to explore the possible aetiology and pathogenesis of neuropsychiatric disturbances following ischaemic stroke (NDIS) from an anatomical and functional perspective with the help of neuroimaging methods. METHOD AND ANALYSIS: CONNECT is a prospective cohort study of neuroimaging and its functional outcome in NDIS. We aim to enrol a minimum of 300 individuals with first-ever stroke. The neuropsychological disturbances involved in this study include depression, anxiety disorder, headache, apathy, insomnia, fatigue and cognitive impairment. Using scales that have been shown to be effective in assessing the above symptoms, the NDIS evaluation battery requires at least 2 hours at baseline. Moreover, all patients will be required to complete 2 years of follow-up, during which the NDIS will be re-evaluated at 3 months, 12 months and 24 months by telephone and 6 months by outpatient interview after the index stroke. The primary outcome of our study is the incidence of NDIS at the 6-month mark. Secondary outcomes are related to the severity of NDIS as well as functional rehabilitation of patients. Functional imaging evaluation will be performed at baseline and 6-month follow-up using specific sequences including resting-state functional MRI, diffusion tensor imaging, T1-weighted imaging, T2-weighted imaging, diffusion-weighted imaging, arterial spin labelling, quantitative susceptibility mapping and fluid-attenuated inversion recovery imaging. In addition, we collect haematological information from patients to explore potential biological and genetic markers of NDIS through histological analysis. ETHICS AND DISSEMINATION: The CONNECT Study was approved by the Ethics Review Committee of the First Hospital of the University of Science and Technology of China (2021-ky012) and written informed consent will be obtained from all participants. Results will be disseminated via a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ChiCTR2100043886.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Humanos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/psicologia , AVC Isquêmico/complicações , Isquemia Encefálica/complicações , Isquemia Encefálica/diagnóstico por imagem , Imagem de Tensor de Difusão , Estudos Prospectivos , Neuroimagem
10.
Cereb Cortex ; 34(2)2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38212287

RESUMO

This study aimed to explore the topographic features of thalamic subregions, functional connectomes and hierarchical organizations between thalamus and cortex in poststroke fatigue patients. We consecutively recruited 121 acute ischemic stroke patients (mean age: 59 years) and 46 healthy controls matched for age, sex, and educational level. The mean age was 59 years (range 19-80) and 38% of acute stroke patients were females. Resting-state functional and structural magnetic resonance imaging were conducted on all participants. The fatigue symptoms were measured using the Fatigue Severity Scale. The thalamic functional subdivisions corresponding to the canonical functional network were defined using the winner-take-all parcellation method. Thalamic functional gradients were derived using the diffusion embedding analysis. The results suggested abnormal functional connectivity of thalamic subregions primarily located in the temporal lobe, posterior cingulate gyrus, parietal lobe, and precuneus. The thalamus showed a gradual increase from the medial to the lateral in all groups, but the right thalamus shifted more laterally in poststroke fatigue patients than in non- poststroke fatigue patients. Poststroke fatigue patients also had higher gradient scores in the somatomotor network and the right medial prefrontal and premotor thalamic regions, but lower values in the right lateral prefrontal thalamus. The findings suggested that poststroke fatigue patients had altered functional connectivity and thalamocortical hierarchical organizations, providing new insights into the neural mechanisms of the thalamus.


Assuntos
Conectoma , AVC Isquêmico , Acidente Vascular Cerebral , Feminino , Humanos , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Masculino , Conectoma/métodos , AVC Isquêmico/patologia , Tálamo/patologia , Imageamento por Ressonância Magnética/métodos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/patologia , Fadiga/diagnóstico por imagem , Fadiga/etiologia
11.
Environ Sci Technol ; 57(48): 19817-19826, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-37972243

RESUMO

Iodate (IO3-) can be abiotically reduced by Fe(II) or biotically reduced by the dissimilatory Fe(III)-reducing bacterium Shewanella oneidensis (MR-1) via its DmsEFAB and MtrCAB. However, the intermediates and stoichiometry between the Fe(II) and IO3- reaction and the relative contribution of abiotic and biotic IO3- reduction by biogenic Fe(II) and MR-1 in the presence of Fe(III) remain unclear. In this study, we found that abiotic reduction of IO3- by Fe(II) produced intermediates HIO and I- at a ratio of 1:2, followed by HIO disproportionation to I- and IO3-. Comparative analyses of IO3- reduction by MR-1 wild type (WT), MR-1 mutants deficient in DmsEFAB or MtrCAB, and Shewanella sp. ANA-3 in the presence of Fe(III)-citrate, Fe(III) oxides, or clay minerals showed that abiotic IO3- reduction by biogenic Fe(II) predominated under iron-rich conditions, while biotic IO3- reduction by DmsEFAB played a more dominant role under iron-poor conditions. Compared to that in the presence of Fe(III)-citrate, MR-1 WT reduced more IO3- in the presence of Fe(III) oxides and clay minerals. The observed abiotic and biotic IO3- reduction by MR-1 under Fe-rich and Fe-limited conditions suggests that Fe(III)-reducing bacteria could contribute to the transformation of iodine species and I- enrichment in natural iodine-rich environments.


Assuntos
Iodo , Shewanella , Compostos Férricos , Oxirredução , Iodatos , Argila , Óxidos , Ferro , Compostos Ferrosos , Minerais , Citratos
12.
Front Microbiol ; 14: 1251346, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37881251

RESUMO

Geobacter sulfurreducens mediates extracellular electron transfer (EET) reactions with different substrates, such as solid-phase Fe(III)-containing minerals, anodes and the cells of Geobacter metallireducens. To compare their roles in EET, the pilA-N, omcE, omcS, omcT and omcZ genes of G. sulfurreducens were systematically deleted. All mutants showed impaired and varied ability to form biofilms on nonconductive surface. Deletion of omcE also impaired bacterial ability to reduce ferrihydrite, but its impacts on the ability for anode reduction and the co-culture of G. metallireducens-G. sulfurreducens were minimal. The mutant without omcS showed diminished ability to reduce ferrihydrite and to form the co-culture, but was able to regain its ability to reduce anodes. Deletion of omcT, omcZ or pilA-N alone impaired bacterial ability to reduce ferrihydrite and anodes and to form the co-culture. Deletion of all tested genes abolished bacterial ability to reduce ferrihydrite and anodes. Triple-deletion of all omcS, omcT and omcZ abolished the ability of G. sulfurreducens to co-culture with G. metallireducens. However, deletion of only omcZ or pilA-N or both omcS and omcT abolished the ability of G. sulfurreducens without hydrogenase gene hybL to co-culture with G. metallireducens, which show their indispensable roles in direct electron transfer from G. metallireducens to G. sulfurreducens. Thus, the roles of pilA-N, omcE, omcS, omcT and omcZ for G. sulfurreducens in EET vary substantially, which also suggest that possession of PilA-N and multiple cytochromes of different structures enables G. sulfurreducens to mediate EET reactions efficiently with substrates of different properties.

13.
Environ Sci Technol ; 57(40): 15277-15287, 2023 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-37751521

RESUMO

Bacterial sulfate reduction plays a crucial role in the mobilization of toxic substances in aquifers. However, the role of bacterial sulfate reduction on iodine mobilization in geogenic high-iodine groundwater systems has been unexplored. In this study, the enrichment of groundwater δ34SSO4 (15.56 to 69.31‰) and its significantly positive correlation with iodide and total iodine concentrations in deep groundwater samples of the North China Plain suggested that bacterial sulfate reduction participates in the mobilization of groundwater iodine. Similar significantly positive correlations were further observed between the concentrations of iodide and total iodine and the relative abundance of the dsrB gene by qPCR, as well as the composition and abundance of sulfate-reducing bacteria (SRB) predicted from 16S rRNA gene high-throughput sequencing data. Subsequent batch culture experiments by the SRB Desulfovibrio sp. B304 demonstrated that SRB could facilitate iodine mobilization through the enzyme-driven biotic and sulfide-driven abiotic reduction of iodate to iodide. In addition, the dehalogenation of organoiodine compounds by SRB and the reductive dissolution of iodine-bearing iron minerals by biogenic sulfide could liberate bound or adsorbed iodine into groundwater. The role of bacterial sulfate reduction in iodine mobilization revealed in this study provides new insights into our understanding of iodide enrichment in iodine-rich aquifers worldwide.


Assuntos
Arsênio , Água Subterrânea , Iodo , Poluentes Químicos da Água , Iodo/análise , Iodetos/análise , RNA Ribossômico 16S/genética , Bactérias/metabolismo , Sulfetos , Sulfatos/análise , China , Poluentes Químicos da Água/análise
14.
Environ Int ; 178: 108067, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37393724

RESUMO

Alkaline ferrous slags pose global environmental issues and long-term risks to ambient environments. To explore the under-investigated microbial structure and biogeochemistry in such unique ecosystems, combined geochemical, microbial, ecological and metagenomic analyses were performed in the areas adjacent to a ferrous slag disposal plant in Sichuan, China. Different levels of exposure to ultrabasic slag leachate had resulted in a significant geochemical gradient of pH (8.0-12.4), electric potential (-126.9 to 437.9 mV), total organic carbon (TOC, 1.5-17.3 mg/L), and total nitrogen (TN, 0.17-1.01 mg/L). Distinct microbial communities were observed depending on their exposure to the strongly alkaline leachate. High pH and Ca2+ concentrations were associated with low microbial diversity and enrichment of bacterial classes Gamma-proteobacteria and Deinococci in the microbial communities exposed to the leachate. Combined metagenomic analyses of 4 leachate-unimpacted and 2-impacted microbial communities led to the assembly of one Serpentinomonas pangenome and 81 phylogenetically diversified metagenome assembled genomes (MAGs). The prevailing taxa in the leachate-impacted habitats (e.g., Serpentinomonas and Meiothermus spp.) were phylogenetically related to those in active serpentinizing ecosystems, suggesting the analogous processes between the man-made and natural systems. More importantly, they accounted for significant abundance of most functional genes associated with environmental adaptation and major element cycling. Their metabolic potential (e.g., cation/H+ antiporters, carbon fixation on lithospheric carbon source, and respiration coupling sulfur oxidization and oxygen or nitrate reduction) may support these taxa to survive and prosper in these unique geochemical niches. This study provides fundamental understandings of the adaptive strategies of microorganisms in response to the strong environmental perturbation by alkali tailings. It also contributes to a better comprehension of how to remediate environments affected by alkaline industrial material.


Assuntos
Bactérias , Microbiota , Humanos , Bactérias/genética , Metagenoma , Tempo (Meteorologia) , Carbono/metabolismo
15.
Brain Sci ; 13(5)2023 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-37239202

RESUMO

Apathy is a common neuropsychiatric disease after stroke and is linked to a lower quality of life while undergoing rehabilitation. However, it is still unknown what are the underlying neural mechanisms of apathy. This research aimed to explore differences in the cerebral activity and functional connectivity (FC) of subjects with post-stroke apathy and those without it. A total of 59 individuals with acute ischemic stroke and 29 healthy subjects with similar age, sex, and education were recruited. The Apathy Evaluation Scale (AES) was used to evaluate apathy at 3 months after stroke. Patients were split into two groups-PSA (n = 21) and nPSA (n = 38)-based on their diagnosis. The fractional amplitude of low-frequency fluctuation (fALFF) was used to measure cerebral activity, as well as region-of-interest to region-of-interest analysis to examine functional connectivity among apathy-related regions. Pearson correlation analysis between fALFF values and apathy severity was performed in this research. The values of fALFF in the left middle temporal regions, right anterior and middle cingulate regions, middle frontal region, and cuneus region differed significantly among groups. Pearson correlation analysis showed that the fALFF values in the left middle temporal region (p < 0.001, r = 0.66) and right cuneus (p < 0.001, r = 0.48) were positively correlated with AES scores in stroke patients, while fALFF values in the right anterior cingulate (p < 0.001, r = -0.61), right middle frontal gyrus (p < 0.001, r = -0.49), and middle cingulate gyrus (p = 0.04, r = -0.27) were negatively correlated with AES scores in stroke patients. These regions formed an apathy-related subnetwork, and functional connectivity analysis unveiled that altered connectivity was linked to PSA (p < 0.05). This research found that abnormalities in brain activity and FC in the left middle temporal region, right middle frontal region, right cuneate region, and right anterior and middle cingulate regions in stroke patients were associated with PSA, revealing a possible neural mechanism and providing new clues for the diagnosis and treatment of PSA.

16.
Sensors (Basel) ; 23(8)2023 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-37112169

RESUMO

The status of zinc oxide (ZnO) arresters is directly related to the safety of power grids. However, as the service life of ZnO arresters increases, their insulation performance may decrease due to factors such as operating voltage and humidity, which can be identified through the measurement of leakage current. Tunnel magnetoresistance (TMR) sensors with high sensitivity, good temperature stability, and small size are excellent for measuring leakage current. This paper constructs a simulation model of the arrester and investigates the deployment of the TMR current sensor and the size of the magnetic concentrating ring. The arrester's leakage current magnetic field distribution under different operating conditions is simulated. The simulation model can aid in optimizing the detection of leakage current in arresters using TMR current sensors, and the findings serve as a basis for monitoring the condition of arresters and improving the installation of current sensors. The TMR current sensor design offers potential advantages such as high accuracy, miniaturization, and ease of distributed application measurement, making it suitable for large-scale use. Finally, the validity of the simulations and conclusions is verified through experiments.

17.
Environ Sci Technol ; 57(13): 5125-5136, 2023 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-36877892

RESUMO

Linking groundwater quality to health will make the invisible groundwater visible, but there are knowledge gaps to understand the linkage which requires cross-disciplinary convergent research. The substances in groundwater that are critical to health can be classified into five types according to the sources and characteristics: geogenic substances, biogenic elements, anthropogenic contaminants, emerging contaminants, and pathogens. The most intriguing questions are related to quantitative assessment of human health and ecological risks of exposure to the critical substances via natural or induced artificial groundwater discharge: What is the list of critical substances released from discharging groundwater, and what are the pathways of the receptors' exposure to the critical substances? How to quantify the flux of critical substances during groundwater discharge? What procedures can we follow to assess human health and ecological risks of groundwater discharge? Answering these questions is fundamental for humans to deal with the challenges of water security and health risks related to groundwater quality. This perspective provides recent progresses, knowledge gaps, and future trends in understanding the linkage between groundwater quality and health.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Humanos , Monitoramento Ambiental/métodos , Água , Poluentes Químicos da Água/análise , Qualidade da Água
18.
Microb Biotechnol ; 16(3): 534-545, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36815664

RESUMO

Protein nanowires are critical electroactive components for electron transfer of Geobacter sulfurreducens biofilm. To determine the applicability of the nanowire proteins in improving bioelectricity production, their genes including pilA, omcZ, omcS and omcT were overexpressed in G. sulfurreducens. The voltage outputs of the constructed strains were higher than that of the control strain with the empty vector (0.470-0.578 vs. 0.355 V) in microbial fuel cells (MFCs). As a result, the power density of the constructed strains (i.e. 1.39-1.58 W m-2 ) also increased by 2.62- to 2.97-fold as compared to that of the control strain. Overexpression of nanowire proteins also improved biofilm formation on electrodes with increased protein amount and thickness of biofilms. The normalized power outputs of the constructed strains were 0.18-0.20 W g-1 that increased by 74% to 93% from that of the control strain. Bioelectrochemical analyses further revealed that the biofilms and MFCs with the constructed strains had stronger electroactivity and smaller internal resistance, respectively. Collectively, these results demonstrate for the first time that overexpression of nanowire proteins increases the biomass and electroactivity of anode-attached microbial biofilms. Moreover, this study provides a new way for enhancing the electrical outputs of MFCs.


Assuntos
Fontes de Energia Bioelétrica , Geobacter , Nanofios , Geobacter/genética , Eletricidade , Transporte de Elétrons , Biofilmes , Eletrodos
19.
Environ Sci Technol ; 57(6): 2625-2635, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36668684

RESUMO

Microorganisms play crucial roles in the global iodine cycling through iodine oxidation, reduction, volatilization, and deiodination. In contrast to iodate formation in radionuclide-contaminated groundwater by the iodine-oxidizing bacteria, microbial contribution to the formation of high level of iodide in geogenic high iodine groundwater is poorly understood. In this study, our results of comparative metagenomic analyses of deep groundwater with typical high iodide concentrations in the North China Plain revealed the existence of putative dissimilatory iodate-reducing idrABP1P2 gene clusters in groundwater. Heterologous expression and characterization of an identified idrABP1P2 gene cluster confirmed its functional role in iodate reduction. Thus, microbial dissimilatory iodate reduction could contribute to iodide formation in geogenic high iodine groundwater. In addition, the identified iron-reducing, sulfur-reducing, sulfur-oxidizing, and dehalogenating bacteria in the groundwater could contribute to the release and production of iodide through the reductive dissolution of iron minerals, abiotic iodate reduction of derived ferrous iron and sulfide, and dehalogenation of organic iodine, respectively. These microbially mediated iodate reduction and organic iodine dehalogenation processes may also result in the transformation among iodine species and iodide enrichment in other geogenic iodine-rich groundwater systems worldwide.


Assuntos
Água Subterrânea , Iodo , Poluentes Químicos da Água , Iodetos/análise , Iodatos/análise , Iodo/análise , Ferro , Bactérias/genética , Bactérias/metabolismo , Oxirredução , China , Enxofre/análise , Poluentes Químicos da Água/análise
20.
Chemosphere ; 315: 137768, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36621689

RESUMO

A pilot-scale anaerobic-anoxic/nitrifying/induced crystallization (A2N-IC) process was established for phosphorus (P) recovery and nutrient removal from municipal wastewater with a treatment capacity of 80 m3d-1. Results show that the A2N-IC process can operate stably on a pilot scale; the recovery efficiency of influent P reached 62.2%, and the total P removal efficiency of the IC section was 65.4%. The IC section had little effect on the removal of chemical oxygen demand (COD) and nitrogen (N), and the P removal efficiency was improved. Soluble non-reactive P (sNRP) was the key factor affecting P recovery efficiency. Although P recovery increases the construction and maintenance costs, the process can be profitable if a market for P recovery products is established. To improve the P recovery efficiency, attention should be paid to the effects of sNRP and dissolved organic matter (DOM) on P recovery, and P-rich sludge should be considered.


Assuntos
Fósforo , Eliminação de Resíduos Líquidos , Humanos , Anaerobiose , Eliminação de Resíduos Líquidos/métodos , Cristalização , Reatores Biológicos , Esgotos/química , Hipóxia , Nitrogênio/análise
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