Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.150
Filtrar
1.
Proc Natl Acad Sci U S A ; 119(19): e2119964119, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35503913

RESUMO

SignificanceMultiheme cytochromes in Shewanella oneidensis MR-1 transport electrons across the cell wall, in a process called extracellular electron transfer. These electron conduits can also enable electron transport along and between cells. While the underlying mechanism is thought to involve a combination of electron hopping and lateral diffusion of cytochromes along membranes, these diffusive dynamics have never been observed in vivo. Here, we observe the mobility of quantum dot-labeled cytochromes on living cell surfaces and membrane nanowires, quantify their diffusion with single-particle tracking techniques, and simulate the contribution of these dynamics to electron transport. This work reveals the impact of redox molecule dynamics on bacterial electron transport, with implications for understanding and harnessing this process in the environment and bioelectronics.


Assuntos
Shewanella , Imagem Individual de Molécula , Membrana Celular/metabolismo , Citocromos/metabolismo , Transporte de Elétrons , Oxirredução , Shewanella/metabolismo
2.
Arch Virol ; 167(5): 1325-1331, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35394245

RESUMO

We present here the results of the analysis of the complete genome sequence of a potentially temperate phage, vB_Sb_QDWS, which was isolated from wastewater samples collected in Qingdao, China. The genome of phage vB_Sb_QDWS is composed of a double-stranded DNA that is 47,902 bp in length with a G + C content of 63.16%. It is predicted to contain 69 putative protein-encoding genes. Microscopic and genomic analysis showed that vB_Sb_QDWS is a novel phage of the class Siphoviridae.


Assuntos
Bacteriófagos , Shewanella , Siphoviridae , Bacteriófagos/genética , DNA Viral/genética , Genoma Viral , Filogenia , Análise de Sequência de DNA , Shewanella/genética , Siphoviridae/genética , Siphoviridae/ultraestrutura
3.
Mar Drugs ; 20(4)2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35447912

RESUMO

Alexandriumpacificum is a typical toxic bloom-forming dinoflagellate, causing serious damage to aquatic ecosystems and human health. Many bacteria have been isolated, having algicidal effects on harmful algal species, while few algicidal bacteria have been found to be able to lyse A. pacificum. Herein, an algicidal bacterium, Shewanella Y1, with algicidal activity to the toxic dinoflagellate A. pacificum, was isolated from Jiaozhou Bay, China, and the physiological responses to oxidative stress in A. pacificum were further investigated to elucidate the mechanism involved in Shewanella Y1. Y1 exhibited a significant algicidal effect (86.64 ± 5.04% at 24 h) and algicidal activity in an indirect manner. The significant declines of the maximal photosynthetic efficiency (Fv/Fm), initial slope of the light limited region (alpha), and maximum relative photosynthetic electron transfer rate (rETRmax) indicated that the Y1 filtrate inhibited photosynthetic activities of A. pacificum. Impaired photosynthesis induced the overproduction of reactive oxygen species (ROS) and caused strong oxidative damage in A. pacificum, ultimately inducing cell death. These findings provide a better understanding of the biological basis of complex algicidal bacterium-harmful algae interactions, providing a potential source of bacterial agent to control harmful algal blooms.


Assuntos
Dinoflagelados , Shewanella , Ecossistema , Proliferação Nociva de Algas , Humanos , Fotossíntese
4.
J Am Chem Soc ; 144(14): 6434-6441, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35377628

RESUMO

The biotic-abiotic photosynthetic system integrating inorganic light absorbers with whole-cell biocatalysts innovates the way for sustainable solar-driven chemical transformation. Fundamentally, the electron transfer at the biotic-abiotic interface, which may induce biological response to photoexcited electron stimuli, plays an essential role in solar energy conversion. Herein, we selected an electro-active bacterium Shewanella oneidensis MR-1 as a model, which constitutes a hybrid photosynthetic system with a self-assembled CdS semiconductor, to demonstrate unique biotic-abiotic interfacial behavior. The photoexcited electrons from CdS nanoparticles can reverse the extracellular electron transfer (EET) chain within S. oneidensis MR-1, realizing the activation of a bacterial catalytic network with light illumination. As compared with bare S. oneidensis MR-1, a significant upregulation of hydrogen yield (711-fold), ATP, and reducing equivalent (NADH/NAD+) was achieved in the S. oneidensis MR-1-CdS under visible light. This work sheds light on the fundamental mechanism and provides design guidelines for biotic-abiotic photosynthetic systems.


Assuntos
Elétrons , Shewanella , Transporte de Elétrons , Hidrogênio , Fotossíntese
5.
J Environ Sci (China) ; 118: 14-20, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35305762

RESUMO

Shewanella sp. ANA-3 with the respiratory arsenate reductase (ArrAB) and MR-1 with ferric reduction ability always coexist in the presence of high arsenic (As)-containing waste residue. However, their synergistic impacts on As transformation and mobility remain unclear. To identify which bacterium, ANA-3 or MR-1, dominates As mobility in the coexisting environment, we explored the As biotransformation in the industrial waste residue in the presence of Shewanella sp. ANA-3 and MR-1. The incubation results show that As(III) was the main soluble species, and strain ANA-3 dominated As mobilization. The impact of ANA-3 was weakened by MR-1, probably due to the survival competition between these two bacteria. The results of micro X-ray fluorescence and X-ray photoelectron spectroscopy analyses further reveal the pathway for ANA-3 to enhance As mobility. Strain ANA-3 almost reduced 100% surface-bound Fe(III), and consequently led to As(V) release. The dissolved As(V) was then reduced to As(III) by ANA-3. The results of this study help to understand the fate of arsenic in the subsurface and highlight the importance of the safe disposal of high As-containing industrial waste.


Assuntos
Arsênio , Shewanella , Purificação da Água , Arsênio/metabolismo , Biotransformação , Compostos Férricos/metabolismo , Shewanella/metabolismo
6.
Emerg Infect Dis ; 28(4): 701-706, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35319435

RESUMO

The epidemiology of bloodstream infections caused by Shewanella spp. is not well defined. Our objective was to define the incidence and determinants of Shewanella spp. bloodstream infections by using population-based surveillance in Queensland, Australia during 2000‒2019. The incidence was 1.0 cases/1 million persons annually and was highest during summer and in the tropical Torres and Cape region. Older persons and male patients were at highest risk. At least 1 concurrent condition was documented in 75% of case-patients, and 30-day all cause case-fatality rate was 15%. Aging populations in warm climates might expect an increasing burden of these infections.


Assuntos
Bacteriemia , Sepse , Shewanella , Idoso , Idoso de 80 Anos ou mais , Austrália/epidemiologia , Bacteriemia/epidemiologia , Humanos , Masculino , Queensland/epidemiologia
7.
Mar Genomics ; 62: 100932, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35246305

RESUMO

Shewanella inventionis D1489, isolated from a marine sediment sample from the Yap trench, is a psychrophile bacterium with optimal and maximum growth temperatures of 17 °C and 37 °C, respectively. Here, we present the complete genome of Shewanella inventionis D1489, which will facilitate the genome mining of eicosapentaenoic acid (EPA) biosynthesis coding gene cluster. The sequenced genome consists of 4,831,636 bases, with mean G + C content of 42.404%. A total of 4295 coding genes including 97 tRNAs and 25 rRNA were predicted in the genome. The genome provides basic genetic information for the understanding of its adaptation to cold environment.


Assuntos
Ácido Eicosapentaenoico , Shewanella , Família Multigênica , Análise de Sequência de DNA , Shewanella/genética
8.
J Hazard Mater ; 431: 128629, 2022 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-35278967

RESUMO

Bioreduction by electroactive bacteria (EAB) is considered as a potential and cost-effective approach for the removal of nitroaromatic compounds (NACs). However, little is known about how the widespread EAB sense and respond to slightly soluble NACs in aquatic environments. Here, the chemotactic behaviors of Shewanella oneidensis MR-1, a model EAB, toward several NACs were examined and their underlying molecular mechanism was elucidated. S. oneidensis MR-1 was found to exhibit a strong chemotactic response to nitrobenzene (NB), but not to other selected NACs under aerobic conditions. To sense NB, this bacterium requires both the histidine kinase (CheA-3)-involved chemotactic signal transduction pathway and an inner-membrane c-type cytochrome CymA. Such a chemotactic response is mediated by an energy taxis mechanism. Additionally, external riboflavin was shown to greatly enhance the Shewanella taxis toward NB, implying a feasible way to increase the bioavailability of NACs. The present study deepens our understanding of the role of microbial chemotaxis in the removal of NACs and provides more options for the bioremediation of NAC-contaminated sites.


Assuntos
Shewanella , Quimiotaxia , Nitrobenzenos/metabolismo , Oxirredução , Shewanella/metabolismo
9.
J Hazard Mater ; 431: 128595, 2022 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-35247734

RESUMO

The immobilized anthraquinone-2-sulfonate (iAQS) could significantly promote anaerobic biotransformation of the contaminants. During this process, the role of flavins secreted by bacteria remains unclear. In the present study, mutual interaction between extracellular flavins and AQS-modified polyurethane foam (AQS-PUF) during the reduction of azo dye Acid Red 18 and 3-nitrobenzenesulfonate (3-NBS) was investigated. Results showed that the amount of extracellular flavins secreted by Shewanella sp. RQs-106 was positively correlated with the concentration of iAQS ranging from 10 to 100 µM. The presence of iAQS resulted in the increased concentration of extracellular and intracellular flavins, implying that iAQS could induce the synthesis and secretion of flavins. The deletion of gene bfe encoding the flavin adenine dinucleotide exporter resulted in approximately 63.8% decrease in the amount of extracellular flavins. Further analysis showed that the decreased amount of extracellular flavins could contribute to around 50.8% reduction of iAQS. Moreover, around 23.2% and 34.0% decreases were observed in AQS-PUF-mediated removal rates of AR 18 and 3-NBS by mutant lacking bfe gene, respectively, compared with that by wild type strain RQs-106. These results indicated that the secreted flavins played an important role in the bio-reduction of AQS-PUF, resulting in their contribution to AQS-PUF-mediated removals of high-polarity aromatic compounds containing nitrogen.


Assuntos
Shewanella , Anaerobiose , Benzoquinonas , Flavinas/metabolismo , Nitrogênio/metabolismo , Oxirredução , Shewanella/metabolismo
10.
J Food Prot ; 85(5): 803-814, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35202469

RESUMO

ABSTRACT: The aim of this research was to experimentally assess the effect of chitosan (CS)-grafted phenolic acid (CS-g-PA) derivatives on the quality and microbiota composition of vacuum-packaged sea bass (Lateolabrax japonicus). Samples were treated by deionized water (CK), 1% CS, 1% CS-g-PA copolymer, and 1% CS-grafted gallic acid (CS-g-GA) copolymer for 10 min and combined with vacuum packaging stored at 4°C to analyze the microbiological and physicochemical indicators; they were also combined with 16s RNA high-throughput sequencing to explore the effects of CS derivatives on quality and microbial composition. The results showed that the treatment of CS-g-GA and CS-g-PA could retard the increase of pH, total volatile basic nitrogen, and the K value. The degradation of ATP-related compounds, production of biogenic amines, and growth of spoilage bacteria were inhibited by CS-g-GA and CS-g-PA. Moreover, CS-g-GA and CS-g-PA performed better in the inhibition of lipid oxidation by the analysis of thiobarbituric acid reactive substances and relative fluorescence intensity. According to the results of high-throughput sequencing, the diversity of microbial composition in all groups was decreased significantly during chilled storage, especially in the CK group. The predominant microorganism was Acinetobacter in the middle period of storage, while Pseudomonas and Shewanella became predominant at the end of storage. The treatment of CS-g-GA and CS-g-PA had significant effects inhibiting the growth of Shewanella during storage. On the basis of the analysis of the microorganism and physicochemical quality, compared with the CK group, CS-g-GA and CS-g-PA can maintain the good quality of sea bass fillets and prolong the shelf life for another 12 days.


Assuntos
Bass , Carpas , Quitosana , Microbiota , Shewanella , Animais , Quitosana/farmacologia , Armazenamento de Alimentos/métodos , Hidroxibenzoatos , Vácuo
11.
Adv Biol (Weinh) ; 6(3): e2101296, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35182055

RESUMO

Shewanella oneidensis MR-1, as a model electroactive microorganism (EAM) for extracellular electron transfer (EET) study, plays a key role in advancing practical applications of bio-electrochemical systems (BES). Efficient genome-level manipulation tools are vital to promote EET efficiency; thus, a powerful and rapid base editing toolbox in S. oneidensis MR-1 is developed. Firstly a CRISPR/dCas9-AID base editor that shows a relatively narrow editing window restricted to the "-20 to -16" range upstream of the protospacer adjacent motif (PAM) is constructed. Cas9 is also confined by its native PAM requirement, NGG. Then to expand the editable scope, the sgRNA and the Cas-protein to broaden the editing window to "-22 to -9" upstream of the PAM are engineered, and the PAM field to NNN is opened up. Consequently, the coverage of the editable gene is expanded from 89% to nearly 100% in S. oneidensis MR-1. This whole genome-scale cytidine deaminase-based base editing toolbox (WGcBE) is applied to regulate the cell length and the biofilm morphology, which enhances the EET efficiency by 6.7-fold. WGcBE enables an efficient deactivation of genes with full genome coverage, which would contribute to the in-depth and multi-faceted EET study in Shewanella.


Assuntos
Sistemas CRISPR-Cas , Shewanella , Elétrons , Edição de Genes , Shewanella/genética
12.
Environ Microbiol ; 24(4): 1838-1848, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35170205

RESUMO

Exoelectrogenic bacteria (EEB) are capable of anaerobic respiration with diverse extracellular electron acceptors including insoluble minerals, electrodes and flavins, but the detailed electron transfer pathways and reaction mechanisms remain elusive. Here, we discover that CymA, which is usually considered to solely serve as an inner-membrane electron transfer hub in Shewanella oneidensis MR-1 (a model EEB), might also function as a reductase for direct reducing diverse nitroaromatic compounds (e.g. 2,4-dichloronitrobenzene) and azo dyes. Such a process can be accelerated by dosing anthraquinone-2,6-disulfonate. The CymA-based reduction pathways in S. oneidensis MR-1 for different contaminants could be functionally reconstructed and strengthened in Escherichia coli. The direct reduction of lowly polar contaminants by quinol oxidases like CymA homologues might be universal in diverse microbes. This work offers new insights into the pollutant reduction mechanisms of EEB and unveils a new function of CymA to act as a terminal reductase.


Assuntos
Poluentes Ambientais , Shewanella , Transporte de Elétrons , Elétrons , Poluentes Ambientais/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Oxirredução , Oxirredutases/genética , Oxirredutases/metabolismo , Shewanella/metabolismo
13.
Chemosphere ; 295: 133861, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35149013

RESUMO

The enrichment of various pollutants in mangrove has attracted widespread attention. Especially, microplastics accumulation in mangrove may provide a more challenging ecological colonization site by enriching pollutants, thus affecting the change of microplastics antibiotic resistance and increasing the risk of antibiotic failure. Herein, the antibiotic-resistant of microplastics and sediment from mangrove were investigated. The results show that isolates are mainly colonized by Vibrio parahemolyticus (V. parahemolyticus), Vibrio alginolyticus (V. alginolyticus), and Shewanella. 100% mangrove microplastics isolates are resistant to chloramphenicol, cefazolin, and tetracycline, especially amoxicillin clavulanate and ampicillin. Meanwhile, the multiple antibiotics resistance (MAR) indexes of V. parahaemolyticus, Shewanella, and V. alginolyticus in mangrove microplastics are 0.72, 0.77, and 0.77, respectively, which are far higher than the MAR index standard (0.2) and that of mangrove sediment isolates. Furthermore, compared with V. parahaemolyticus isolated from the same mangrove microplastics, Shewanella and V. alginolyticus show stronger drug resistance. It should be noted that there is a closely related relationship between the type of microplastics and the antibiotics resistance of isolated bacteria. For the antibiotics sensitivity test of norfloxacin, streptomycin, amoxicillin, and chloramphenicol, V. parahaemolyticus have the lower antibiotics resistance than that of V. alginolyticus isolated from the same mangrove microplastics. However, Vibrio isolated from PE has stronger antibiotics resistance. Results reveal that mangrove may be one of the potential risks for emergence and spread of bacterial antibiotics-resistant and multidrug-resistant, and microplastic biofilms may act as promoters of bacterial antibiotic resistance.


Assuntos
Shewanella , Vibrio parahaemolyticus , Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Testes de Sensibilidade Microbiana , Microplásticos , Plásticos
14.
Microb Genom ; 8(2)2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35143386

RESUMO

Shewanella algae is widely distributed in marine and freshwater habitats, and has been proved to be an emerging marine zoonotic and human pathogen. However, the genomic characteristics and pathogenicity of Shewanella algae are unclear. Here, the whole-genome features of 55 S. algae strains isolated from different sources were described. Pan-genome analysis yielded 2863 (19.4 %) genes shared among all strains. Functional annotation of the core genome showed that the main functions are focused on basic lifestyle such as metabolism and energy production. Meanwhile, the phylogenetic tree of the single nucleotide polymorphisms (SNPs) of core genome divided the 55 strains into three clades, with the majority of strains from China falling into the first two clades. As for the accessory genome, 167 genomic islands (GIs) and 65 phage-related elements were detected. The CRISPR-Cas system with a high degree of confidence was predicted in 23 strains. The GIs carried a suite of virulence genes and mobile genetic elements, while prophages contained several transposases and integrases. Horizontal genes transfer based on homology analysis indicated that these GIs and prophages were parts of major drivers for the evolution and the environmental adaptation of S. algae. In addition, a rich putative virulence-associated gene pool was found. Eight classes of antibiotic-associated resistance genes were detected, and the carriage rate of ß-lactam resistance genes was 100 %. In conclusion, S. algae exhibits a high intra-species diversity in the aspects of population structure, virulence-associated genes and potential drug resistance, which is helpful for its evolution in pathogenesis and environmental adaptability.


Assuntos
Variação Genética , Genômica , Shewanella/genética , Adaptação Biológica , Antibacterianos/farmacologia , Sistemas CRISPR-Cas , China , Farmacorresistência Bacteriana/genética , Genoma Bacteriano , Ilhas Genômicas , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Prófagos/genética , Shewanella/classificação , Shewanella/efeitos dos fármacos , Shewanella/isolamento & purificação , Especificidade da Espécie , Virulência/genética
15.
Arch Microbiol ; 204(3): 198, 2022 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-35218433

RESUMO

A Gram-stain-negative and facultatively anaerobic bacterial strain designated as JM162201T was isolated from aquaculture water for farming Pacific white shrimp (Litopenaeus vannamei). The genome size of strain JM162201T was 4,436,316 bp, and the genomic DNA G + C content was 55.0%. Phylogenetic analysis based on 16S rRNA gene sequences and genomes showed that strain JM162201T belonged to the genus Shewanella and was closely related to Shewanella litorisediminis SMK1-12T (97.1%), Shewanella khirikhana TH2012T (97.0%), and Shewanella amazonensis SB2BT (96.0%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain JM162201T and three reference type strains were below the recognized thresholds of 95.0-96.0% (for ANI) and 70.0% (for dDDH) for species delineation. Growth occurred at 10-40 °C (optimum, 30 °C), at pH 4.0-10.0 (optimum, 7.0-8.0), and in 0-6.0% NaCl (w/v, optimum, 0-0.1%). The major cellular fatty acids of strain JM162201T were summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C17:1 ω8c, iso-C15:0, C16:0, and C15:0. The predominant quinones were MK7, Q-7, and Q-8. The major polar lipids were phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). Based on the polyphasic taxonomical analyses, strain JM162201T represents a novel species of the genus Shewanella, for which the name Shewanella jiangmenensis sp. nov. is proposed, with the type strain JM162201T (= GDMCC 1.2006T = KCTC 82340T).


Assuntos
Shewanella , Água , Aquicultura , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Ácidos Graxos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Shewanella/genética
16.
Anal Bioanal Chem ; 414(9): 3057-3066, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35192018

RESUMO

Water toxicity detection is of great significance to ensure the safety of water supply. With suspended electrochemically active bacteria (EAB) as the sensing element, a novel microbial electrochemical sensor (MES) has recently been reported for the real-time detection of water toxicity, but its practical applications need to further improve the sensitivity. Extracellular electron transfer (EET) is an important factor affecting MES performance. In the study, the EET of suspended EAB-based MES was optimized to further enhance the sensitivity. Firstly, by using a model EAB stain Shewanella oneidensis MR-1, it was revealed that the sensitivity was increased at most 2.7 times with inward EET (i.e., cathodic polarization). Then, a novel conjecture based on electron transfer and energy fluxes was proposed and testified to explain this phenomenon. Finally, three key operating parameters of inward EET were orthogonally optimized. The optimized parameters of inward EET included a potential of - 0.5 V, a cell density of 1.8 × 108 CFU/mL, and an electron acceptor concentration of 15 mM.


Assuntos
Shewanella , Água , Transporte de Elétrons , Elétrons
17.
Environ Sci Technol ; 56(6): 3812-3820, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35226466

RESUMO

Functional material synthesis through biomineralization is effective and environmentally friendly. Biomineralized manganese (Mn) oxides are important for remediation and energy storage. Manganese(II) biomineralization is achieved by a diverse group of bacteria. We show that in the presence of oxygen the dissimilatory manganese-reducing bacterium Shewanella putrefaciens CN32 can oxidize Mn(II). The Mn(II) oxidation was accelerated with the increase in the initial Mn(II) concentration from 0.5 to 3 mM. The reaction was mainly associated with a cell-free filtrate, rather than the direct enzymatic oxidation or indirect oxidation by reactive oxygen species or macrocyclic siderophores. Instead, indirect oxidization of Mn(II) into soluble Mn(III) and bixbyite-like Mn2O3 via microbially produced extracellular ligands (molecular weights of 1-3 kDa) was identified. This work broadens our view about microbial Mn(II) oxidation and unveils the important roles of Shewanella species in the geochemical cycling of manganese.


Assuntos
Shewanella putrefaciens , Shewanella , Ligantes , Manganês , Compostos de Manganês/química , Oxirredução , Óxidos/química
18.
Environ Sci Technol ; 56(4): 2366-2377, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35107264

RESUMO

Silver ions (Ag+) directly emitted from industrial sources or released from manufactured Ag nanoparticles (AgNPs) in biosolid-amended soils have raised concern about the risk to ecosystems. However, our knowledge of Ag+ toxicity, internalization, and transformation mechanisms to bacteria is still insufficient. Here, we combine the advanced technologies of hyperspectral imaging (HSI) and single-particle inductively coupled plasma mass spectrometry to visualize the potential formed AgNPs inside the bacteria and evaluate the contributions of biological and non-biological processes in the uptake and transformation of Ag+ by Shewanella oneidensis MR-1. The results showed a dose-dependent toxicity of Ag+ to S. oneidensis MR-1 in the ferrihydrite bioreduction process, which was primarily induced by the actively internalized Ag. Moreover, both HSI and cross-section high-resolution transmission electron microscopy results confirmed that Ag inside the bacteria existed in the form of particulate. The Ag mass distribution in and around live and inactivated cells demonstrated that the uptake and transformation of Ag+ by S. oneidensis MR-1 were mainly via biological process. The bioaccumulation of Ag+ may be lethal to bacteria. A better understanding of the uptake and transformation of Ag+ in bacteria is central to predict and monitor the key factors that control Ag partitioning dynamics at the biointerface, which is critical to develop practical risk assessment and mitigation strategies.


Assuntos
Nanopartículas Metálicas , Shewanella , Ecossistema , Nanopartículas Metálicas/química , Prata/química
19.
J Glob Antimicrob Resist ; 28: 140-142, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35021125

RESUMO

OBJECTIVES: Tigecycline resistance mediated by the mobile tigecycline-inactivating enzyme gene tet(X) in Gram-negative bacteria is an emerging concern for global public health. However, limited information is available on the distribution of tet(X) in the natural environment. In this study, we investigated the presence of tet(X) in environmental Gram-negative bacteria. METHODS: A carbapenem- and tigecycline-resistant Shewanella xiamenensis isolate (NUITM-VS1) was obtained from an urban drainage in Hanoi, Vietnam, in March 2021. Whole-genome sequencing analysis was performed by long- and short-read sequencing, resulting in a complete genome sequence. Antimicrobial resistance genes (ARGs) in the genome were detected based on the custom ARG database, including all known tigecycline resistance genes. RESULTS: Shewanella xiamenensis isolate NUITM-VS1 harboured the tet(X4) gene and the blaOXA-48 carbapenemase gene on the chromosome. tet(X4) was flanked by IS91 family transposase genes, suggesting that the acquisition of tet(X4) was mediated by this mobile gene element (MGE), whereas no MGE was found surrounding blaOXA-48, consistent with previous findings that blaOXA-48-like ß-lactamase genes are species-specific intrinsic ARGs in Shewanella spp. CONCLUSION: To the best of our knowledge, this is the first report of a tet(X4)-harbouring Shewanella sp. isolate. Our results provide genetic evidence of the complexity of the dynamics of clinically important ARGs among bacteria in the water environment.


Assuntos
Shewanella , Antibacterianos/farmacologia , Bactérias Gram-Negativas , Testes de Sensibilidade Microbiana , Shewanella/genética , Tigeciclina , Água
20.
Sci Total Environ ; 820: 153286, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35074363

RESUMO

Very little is known about how microbiome interactions shape the horizontal transfer of antibiotic resistance genes in aquacultural environment. To this end, we first conducted 16S rRNA gene amplicon sequencing to monitor the dynamics of bacterial community compositions in one shrimp farm from 2019 to 2020. Next, co-occurrence analysis was then conducted to reveal the interactions network between Vibrio spp. and other species. Subsequently, 21 V. parahaemolyticus isolates and 15 related bacterial species were selected for whole-genome sequencing (WGS). The 16S rDNA amplicon sequencing results identified a remarkable increase of Vibrio and Providencia in September-2019 and a significant rise of Enterobacter and Shewanella in Septtember-2020. Co-occurrence analysis revealed that Vibrio spp. positively interacted with the above species, leading to the sequencing of their isolates to further understand the sharing of the resistant genomic islands (GIs). Subsequent pan-genomic analysis of V. parahaemolyticus genomes identified 278 horizontally transferred genes in 10 GIs, most of which were associated with antibiotic resistance, virulence, and fitness of metabolism. Most of the GIs have also been identified in Providencia, and Enterobacter, suggesting that exchange of genetic traits might occur in V. parahaemolyticus and other cooperative species in a specific niche. No genetic exchange was found between the species with negative relationships. The knowledge generated from this study would greatly improve our capacity to predict and mitigate the emergence of new resistant population and provide practical guidance on the microbial management during the aquacultural activities.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana , Transferência Genética Horizontal , Vibrio parahaemolyticus , Antibacterianos/farmacologia , Aquicultura , Farmacorresistência Bacteriana/genética , Enterobacter/genética , Genes Bacterianos , Genoma Bacteriano , Providencia/genética , RNA Ribossômico 16S , Shewanella/genética , Vibrio parahaemolyticus/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...