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1.
Chemosphere ; 246: 125681, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31896014

RESUMO

Tetracycline (TC) as an emerging contaminant has raised serious concerns about its toxicity and removal in wastewater treatment processes. The more toxic transformation products of TC, 4-epitetracycline (ETC), anhydrotetracycline (ATC) and 4-epianhydrotetracycline (EATC) are also widely detected. This study investigated the antibacterial and bactericidal activity of TC, ETC, ATC, EATC against Shewanella sp, using Escherichia coli and Pseudomonas aeruginosa strains as quality controls. Further, batch assays were conducted to investigate the inhibition of these antibiotics on the phosphorus removal of the Shewanella strain, and removal mechanisms of TC and its transformation products (TCs). The inhibition on phosphorus removal by the Shewanella strain at 20 mg L-1 was in the order of ATC > EATC > TC > ETC. COD removal, poly-P accumulation and glycogen synthesis by the Shewanella strain were also inhibited. Biodegradation was the main removal mechanism of TC and ETC, while adsorption was the main one of ATC and EATC. This study helps to further understand the structure-activity relationship of TC.


Assuntos
Antibacterianos/toxicidade , Fósforo/metabolismo , Shewanella/efeitos dos fármacos , Tetraciclina/toxicidade , Adsorção , Compostos Heterocíclicos , Shewanella/metabolismo , Tetraciclina/análise , Tetraciclinas/análise , Águas Residuárias
2.
Food Microbiol ; 86: 103313, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703873

RESUMO

This study investigated the effect of phytic acid and lysozyme on the microbial composition and quality of grass carp (Ctenopharyngodon idellus) fillets stored at 4 °C. The control, 0.5 mg/mL lysozyme-treated fillets (T1), 0.5 mg/mL phytic acid-treated fillets (T2) and 0.25 mg/mL lysozyme + 0.25 mg/mL phytic acid-treated fillets (T3) were evaluated based on sensory assessment, biogenic amines, ATP-related compounds, total volatile basic nitrogen (TVB-N), and total viable counts (TVC). Changes in microbial composition were analyzed using high-throughput sequencing. Results showed that phytic acid and lysozyme treatment delayed the decrease in sensory scores, reduced the rate of degradation of IMP to Hx, inhibited the growth of microorganisms, and attenuated the increase in TVB-N and putrescine. Phytic acid exhibited better preservation effects than lysozyme and their combination was more effective than using either alone. High-throughput sequencing showed that Acinetobacter and Kocuria were the predominant bacteria in fresh grass carp, but Pseudomonas rose rapidly with storage time; Pseudomonas, Shewanella, and Aeromonas constituted the main spoilage bacteria of grass carp fillets. Lysozyme treatment significantly reduced the proportion of Shewanella and Acinetobacter, and phytic acid and the combination of phytic acid and lysozyme significantly reduced the proportion of Pseudomonas in spoiled grass carp fillets.


Assuntos
Carpas/microbiologia , Produtos Pesqueiros/microbiologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Microbiota/efeitos dos fármacos , Muramidase/farmacologia , Ácido Fítico/farmacologia , Acinetobacter/efeitos dos fármacos , Acinetobacter/crescimento & desenvolvimento , Aeromonas/efeitos dos fármacos , Aeromonas/crescimento & desenvolvimento , Animais , Aminas Biogênicas/análise , Conservação de Alimentos/instrumentação , Armazenamento de Alimentos , Humanos , Pseudomonas/efeitos dos fármacos , Pseudomonas/crescimento & desenvolvimento , Shewanella/efeitos dos fármacos , Shewanella/crescimento & desenvolvimento , Paladar
3.
Environ Sci Process Impacts ; 21(10): 1736-1744, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31498354

RESUMO

Steroid estrogens (SEs), especially 17ß-estradiol (E2), can be a serious threat to the health of organisms. The removal of E2 from the natural environment is mainly carried out by microbial degradation partly mediated by biochar, which contains quinone structures. In this study, reed straw biochar samples made at four different heat treatment temperatures (HTTs) were used to mediate E2 microbial degradation by Shewanella oneidensis MR-1. The removal efficiency of E2 (95%) was highest in the presence of HTT - 500 °C biochar under anaerobic conditions after 120 h of microbial degradation. The effect of biochar on promoting microbial degradation was far more superior under anaerobic conditions than under aerobic conditions. The redox-activity and types of surface functional groups of biochar reveal that biochar can accept electrons generated by microorganisms in a timely manner. This mechanism promotes the metabolic process of cells and microbial degradation of E2 (exponential increase). Biochar particles rather than biochar-derived water-soluble organic compounds are responsible for this stimulating effect. These results highlight the impact that biochar has on microbial degradation of trace pollutants in a natural environment.


Assuntos
Carvão Vegetal/química , Estradiol/metabolismo , Shewanella/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Estradiol/análise , Estrogênios/metabolismo , Microscopia Eletrônica de Varredura , Oxirredução , Shewanella/efeitos dos fármacos , Acetato de Sódio/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
4.
Bioresour Technol ; 291: 121858, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377515

RESUMO

The improved performances during anaerobic degradation of phenol to methane with Fe(OH)3 were usually inapparent, due to its lower solubility (unaccessible to dissimilatory iron reduction) and more positive reduction potential of Fe(III)/Fe(II) (unfavorable for enriching Fe(III)-reducing bacteria [IRBs]). In this study, citrate, the organic chelates, were used to solubilize Fe(III) with the aim of improving the phenol degradation and declining the reduction potential of Fe(III)/Fe(II). Results showed that, in the co-occurrence of citrate and Fe(OH)3, the degradation rates of phenol were about 1.3-fold rapider than that with sole Fe(OH)3. Analysis of cyclic voltammetry demonstrated that the reduction potential of Fe(III)/Fe(II) in the form of Fe(OH)3 (-0.41 to -0.28 V vs Ag/AgCl) declined to -0.61 to -0.41 V. As a result, the Fe(III)-reducing genera, such as Petrimonas and Shewanella, which held a great potential of proceeding syntrophic metabolism via direct interspecies electron transfer (DIET), were significantly enriched.


Assuntos
Quelantes/farmacologia , Compostos Férricos/metabolismo , Ferro/metabolismo , Metano/metabolismo , Fenol/metabolismo , Anaerobiose , Bacteroides/efeitos dos fármacos , Bacteroides/metabolismo , Transporte de Elétrons , Oxirredução , Fenóis/metabolismo , Shewanella/efeitos dos fármacos , Shewanella/metabolismo
5.
Appl Biochem Biotechnol ; 189(1): 103-115, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30868384

RESUMO

The human exposure to bisphenol A (BPA) occurs frequently. Once, this compound was one of the highest volume chemicals produced worldwide and used as a plasticizer in many products. However, even at low concentration, it can cause severe damage to the endocrine system because of its endocrine disruptor activity. Thus, mitigation studies to remove or reduce this contaminant from the environment are essential. An alternative method of removing it from the environment is the use of bioremediation processes to the selected bacteria isolated from a BPA-impacted area. In this work, four halotolerant strains were isolated from the Santos Estuary System, one of the most important Brazilian examples of environmental degradation. In the present work, one strain presented strong BPA tolerance and high BPA-degrading activity and could grow in a minimum medium containing BPA as the main carbon source. Strain MH137742 was identified as Shewanella haliotis, based on 16S rRNA gene sequencing and mass spectrometry identification by MALDI-TOF Biotyper. Shewanella haliotis was able to tolerate up to 150 mg L-1 of BPA and biotransform 75 mg L-1 in 10 h in a liquid culture medium. Based on the analysis of the produced metabolites by LC-MS, it was possible to predict the metabolic pathway used by this microorganism to degrade the BPA.


Assuntos
Compostos Benzidrílicos/metabolismo , Compostos Benzidrílicos/farmacologia , Biodegradação Ambiental , Estuários , Fenóis/metabolismo , Fenóis/farmacologia , Shewanella/efeitos dos fármacos , Redes e Vias Metabólicas , RNA Ribossômico 16S/genética , Análise de Sequência de RNA , Shewanella/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
6.
Environ Int ; 127: 94-102, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30909098

RESUMO

Hexavalent chromium [Cr(VI)] is a priority heavy metal pollutant causing a series of environmental issues, and bio-reduction of Cr(VI) to trivalent chromium can remarkably decrease the environmental risk of Cr(VI). The reduction and resistance abilities of microorganisms to Cr(VI) can be dramatically improved by acclimatization. In the present study, we collected Shewanella oneidensis MR-1 from a 120-day acclimatization by increasing Cr(VI) concentration in the culture media to investigate its adaptation mechanisms under long-term Cr(VI) stress at the proteome level. Tandem mass tag-based quantitative proteomic analysis was performed to study the differences between 9 collected samples. A total of 2500 proteins were quantified from 2723 identified protein groups. Bioinformatics analysis showed that the differentially expressed proteins after the 120-day Cr(VI) acclimatization were mostly related to flagellar assembly, ribosomes, transport, sulfur metabolism, and energy metabolism. The findings of this study present novel insights into the molecular mechanisms for the reduction and resistance of S. oneidensis MR-1 responding to long-term Cr(VI) stress at the proteome level.


Assuntos
Cromo/farmacologia , Poluentes Ambientais/toxicidade , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Proteoma/metabolismo , Shewanella/efeitos dos fármacos , Shewanella/metabolismo , Oxirredução , Proteômica
7.
Biotechnol Bioeng ; 116(1): 54-64, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30320445

RESUMO

Understanding the dynamics of biofilm development in response to chemical cues and signals is required toward the development of controllable biofilm-mediated bioprocesses. In this study, we report a new biofilm growth system that integrates a microfluidic gradient mixer with a biofilm growth chamber. The biofilm growth system allows biofilms to grow under defined solute gradients and enables nondestructive monitoring of the biofilm development dynamics in response to the defined gradients. The solute gradients generated in the system were simulated and then validated experimentally. We then demonstrated the applicability of the biofilm growth system in studying biofilm development under defined solute gradients. Specifically, we examined biofilm development of Shewanella oneidensis and Comamonas testosteroni under a defined calcium and nitrate gradient, respectively. Using two C. testosteroni strains (WDL7 and I2), we further demonstrated the applicability of our biofilm growth system to study the development of coculture biofilms under a defined solute gradient. Our results show that the biofilm growth system we have developed here can be a promising tool to reveal the dynamics of biofilm development in response to chemical cues and signals as well as the interorganism interactions in coculture biofilms.


Assuntos
Biofilmes/crescimento & desenvolvimento , Comamonas testosteroni/efeitos dos fármacos , Meios de Cultura/química , Dispositivos Lab-On-A-Chip , Microfluídica/instrumentação , Microfluídica/métodos , Shewanella/efeitos dos fármacos , Cálcio/metabolismo , Comamonas testosteroni/crescimento & desenvolvimento , Nitratos/metabolismo , Shewanella/crescimento & desenvolvimento
8.
Food Microbiol ; 78: 114-122, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30497593

RESUMO

Shewanella spp. are major causes of fish spoilage. Terminalia ferdinandiana (Kakadu plum) extracts were investigated for their ability to inhibit Shewanella spp. growth. Leaf and fruit extracts displayed potent growth inhibitory properties against all Shewanella spp. The methanolic leaf extract was a particularly potent inhibitor of S. putrefaciens (DD MIC 93; LD MIC 73 µg/mL), S. baltica (DD MIC 104 µg/mL; LD MIC 85 µg/mL), S. frigidimarina (DD MIC 466 µg/mL; LD MIC 391 µg/mL) and S. loihica (DD MIC 95 µg/mL; LD MIC 55 µg/mL) growth. The aqueous and ethyl acetate leaf extracts were also potent growth inhibitors, with MIC values generally substantially <1000 µg/mL. Treatment of Acanthopagrus butcheri Munro fillets with methanolic Kakadu plum extracts significantly inhibited bacterial growth for 15 days at 4 °C. All Kakadu plum extracts were nontoxic in the Artemia franciscana bioassay. LC-MS analysis identified several compounds which may contribute to the inhibition of Shewanella spp. growth.


Assuntos
Peixes/microbiologia , Extratos Vegetais/farmacologia , Alimentos Marinhos/microbiologia , Shewanella/efeitos dos fármacos , Terminalia/química , Animais , Artemia/efeitos dos fármacos , Bioensaio , Frutas/química , Metanol/química , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Extratos Vegetais/toxicidade , Folhas de Planta/química , RNA Ribossômico 16S , Shewanella/crescimento & desenvolvimento , Terminalia/anatomia & histologia
9.
Future Microbiol ; 13: 1709-1717, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30477345

RESUMO

AIM: To describe the genomic characteristics of seawater-borne hemolytic Shewanella algae and its resistance genes. MATERIALS & METHODS: Whole genome sequence of S. algae SYT3 was determined using llumina MiSeq platform. Multiple-database-based analysis was performed to identify the genetic background of its hemolytic activity and the antibiotic resistance genes. RESULTS: S. algae SYT3 possesses a homolog of the hly operon involved in the synthesis of hemolysin. We also identified candidate genes associated with resistance to ß-lactam antibiotics (bla OXA-55) and fluoroquinolone (qnrA3). CONCLUSION: The study provides an insight into the hemolytic activity of S. algae. Our findings also suggested S. algae as a potential reservoir of antimicrobial resistance determinants.


Assuntos
Farmacorresistência Bacteriana/genética , Genoma Bacteriano , Hemólise , Água do Mar/microbiologia , Shewanella/genética , Shewanella/isolamento & purificação , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Mapeamento Cromossômico , DNA Bacteriano/genética , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Filogenia , RNA Ribossômico 16S/genética , Shewanella/classificação , Shewanella/efeitos dos fármacos , Taiwan , Sequenciamento Completo do Genoma , beta-Lactamases/genética
10.
ACS Synth Biol ; 7(12): 2726-2736, 2018 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-30396267

RESUMO

The relative scarcity of well-defined genetic and metabolic linkages to material properties impedes biological production of inorganic materials. The physiology of electroactive bacteria is intimately tied to inorganic transformations, which makes genetically tractable and well-studied electrogens, such as Shewanella oneidensis, attractive hosts for material synthesis. Notably, this species is capable of reducing a variety of transition-metal ions into functional nanoparticles, but exact mechanisms of nanoparticle biosynthesis remain ill-defined. We report two key factors of extracellular electron transfer by S. oneidensis, the outer membrane cytochrome, MtrC, and soluble redox shuttles (flavins), that affect Pd nanoparticle formation. Changes in the expression and availability of these electron transfer components drastically modulated particle synthesis rate and phenotype, including their structure and cellular localization. These relationships may serve as the basis for biologically tailoring Pd nanoparticle catalysts and could potentially be used to direct the biogenesis of other metal nanomaterials.


Assuntos
Nanopartículas Metálicas/química , Paládio/química , Shewanella/metabolismo , Grupo dos Citocromos c/deficiência , Grupo dos Citocromos c/genética , Grupo dos Citocromos c/metabolismo , Transporte de Elétrons , Elétrons , Expressão Gênica , Nanopartículas Metálicas/toxicidade , Oxirredução , Tamanho da Partícula , Fenótipo , Shewanella/efeitos dos fármacos
11.
BMC Infect Dis ; 18(1): 454, 2018 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-30185170

RESUMO

BACKGROUND: Members of Shewanella species are opportunistic pathogens that are found in marine environments. Currently more than sixty species have been identified, whereas the most commonly clinical cases associated with Shewanella species have involved only two species, i.e., S. algae and S. putrefaciens. We present two cases of pulmonary and bloodstream infections caused by two rare Shewanella spp. strains from patients of gastrointestinal cancer. CASE PRESENTATION: Two male patients with a history of gastrointestinal cancer presented to hospital with pulmonary and bloodstream infections, respectively. The infective pathogens of both cases were primarily isolated and identified as Shewanella algae (case I) and Shewanella putrefaciens (case II) by phenotypic features and VITEK 2 system, but they were further confirmed as Shewanella haliotis and Shewanella upenei by 16S rRNA gene sequence analysis. The major bacterial composition of the bronchoalveolar lavage in case I was also identified as Shewanella by 16S rRNA amplicon sequencing analysis. Antimicrobial susceptibility testing showed that the two strains had broad susceptibility, but S. haliotis in the case I was resistant to ciprofloxacin and levofloxacin and S. upenei in the case II was intermediate to imipenem, piperacillin/tazobactam and ciprofloxacin. CONCLUSIONS: To the best of our knowledge, this is the first cases of the pulmonary and bloodstream infections caused by Shewanella spp. from clinical patients in mainland China. Shewanella as a potential pathogen in China should not be ignored.


Assuntos
Neoplasias Esofágicas/diagnóstico , Infecções por Bactérias Gram-Negativas/diagnóstico , Shewanella/isolamento & purificação , Neoplasias Gástricas/diagnóstico , Idoso , Antibacterianos/farmacologia , Líquido da Lavagem Broncoalveolar/microbiologia , China , Neoplasias Esofágicas/complicações , Infecções por Bactérias Gram-Negativas/complicações , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Filogenia , RNA Ribossômico 16S/genética , Shewanella/classificação , Shewanella/efeitos dos fármacos , Shewanella/genética , Neoplasias Gástricas/complicações
12.
Artigo em Inglês | MEDLINE | ID: mdl-30082287

RESUMO

OXA-535 is a chromosome-encoded carbapenemase of Shewanella bicestrii JAB-1 that shares only 91.3% amino acid sequence identity with OXA-48. Catalytic efficiencies are similar to those of OXA-48 for most ß-lactams, except for ertapenem, where a 2,000-fold-higher efficiency was observed with OXA-535. OXA-535 and OXA-436, a plasmid-encoded variant of OXA-535 differing by three amino acids, form a novel cluster of distantly related OXA-48-like carbapenemases. Comparison of blaOXA-535 and blaOXA-436 genetic environments suggests that an ISCR1 may be responsible for blaOXA-436 gene mobilization from the chromosome of Shewanella spp. to plasmids.


Assuntos
Shewanella/enzimologia , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carbapenêmicos/farmacologia , Cromossomos Bacterianos/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Shewanella/efeitos dos fármacos , Shewanella/genética , beta-Lactamases/genética , beta-Lactamas/farmacologia
13.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1863(10): 1153-1163, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30037760

RESUMO

It is fully established that the condensing reaction for the initiation of fatty acid synthesis is essential for viability of many bacteria. In model bacteria such as Escherichia coli, this reaction is exclusively catalyzed by ß-ketoacyl-ACP synthase (KAS) III (encoded by fabH) and the FabH loss results in a fatty acid auxotroph. However, such a notion has been under the challenge of recent findings. In an attempt to resolve the conflicting results, in this study, we examined the physiological role of multiple KASIII enzyme homologues in Shewanella oneidensis, an excellent model for researching type II fatty acid synthesis (FASII) and its regulation. We demonstrated that FabH1 and temperature-responsive FabH2 are primarily responsible for initiating synthesis of straight- and branched-chain fatty acids respectively, whereas FabH3 and OleA are dispensable. Cells lacking all these enzymes as a set are viable but carry severe defects in growth. Further analyses revealed that in the absence of KASIII either of FabB (KASI) and FabF2 (KASII) is able to support growth, suggesting that they could initiate FASII. Strikingly, KASIII enzymes and OleA together confer S. oneidensis cells resistance to cerulenin, a selective inhibitor of FabF and FabB. Along with our previous finding that S. oneidensis FabF1 and FabB are fully equivalent with respect to their physiological impacts, these results imply that physiological function promiscuity of bacterial KAS enzymes could be more extensive than previously expected.


Assuntos
Proteínas de Bactérias/metabolismo , Cerulenina/farmacologia , Ácidos Graxos/biossíntese , Homologia de Sequência de Aminoácidos , Shewanella/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Simulação por Computador , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genes Bacterianos , Shewanella/efeitos dos fármacos , Shewanella/genética , Shewanella/crescimento & desenvolvimento , Temperatura , Transcrição Genética/efeitos dos fármacos
14.
Environ Toxicol Pharmacol ; 62: 156-163, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30029095

RESUMO

The ability of anthraquinone-2,6-disulfonate (AQDS) and riboflavin to enhance the sulfamethoxazole (SMX) degradation coupled with the Fe(III) reduction by Shewanella oneidensis MR-1 was investigated. The results indicated that the SMX degradation rate was 38.5% with an initial SMX concentration at 0.04 mM. For the overall performance of AQDS and riboflavin mediated SMX degradation and iron reduction, the SMX degradation rate was gradually increased with the enhancement of iron reduction. Riboflavin had a stronger enhancement on SMX degradation and iron reduction than AQDS, but the enhancement was not positively correlated with electron shuttles concentration. A quantitative characterization of the electron transfer capacity (ETC) of the electron shuttles showed that the ETC was higher for riboflavin than AQDS. The S. oneidensis MR-1 16S rRNA gene copies results indicated that electron shuttles had a positive effect on the microbial activity of S. oneidensis MR-1. The LCMS result indicated that the products of the SMX biodegradation were 3-amino-5-methylisoxazole and 4-aminobenzenesulfonic acid, which suggested that the SMX biodegradation was caused by SN bond cleavage. This study indicates that the biochemical mechanisms play a vital role in SMX transformation and Fe(II) generation in this system.


Assuntos
Antraquinonas/farmacologia , Ferro/metabolismo , Riboflavina/farmacologia , Shewanella/efeitos dos fármacos , Sulfametoxazol/metabolismo , Biodegradação Ambiental/efeitos dos fármacos , Elétrons , Oxirredução , RNA Ribossômico 16S , Shewanella/genética , Shewanella/metabolismo
15.
Anal Sci ; 34(10): 1177-1182, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-29910222

RESUMO

Shewanella can transfer electrons to various extracellular electron acceptors. We electrochemically investigated the pathway of extracellular electron transfer from Shewanella strain Hac319 to electrodes. A resting cell suspension of Shewanella strain Hac319 containing lactate produced a steady-state sigmoidal wave in the presence of flavin mononucleotide (FMN) in cyclic voltammetry, but not in the absence of FMN. A harvested cell suspension without cell-washing also produced a similar catalytic wave without any external addition of free FMN. The midpoint potentials of the two sigmoidal waves were identical to the redox potential of free FMN. The data indicate that FMN secreted from the Shewanella strain Hac319 works as an electron-transfer mediator from the cell to electrodes. An addition of cyanide to a resting cell suspension of Shewanella strain Hac319 increased the rate of the FMN reduction in the presence of lactate, while it decreased the respiration rate. By considering the fact that cyanide is coordinated to the heme moiety of hemoproteins and shifts the redox potential to the negative potential side, the data indicate that the electron derived from lactate is predominantly transferred in a down-hill mode from an electron donor with a redox potential more negative than that of FMN without going through outer membrane cytochromes c molecules.


Assuntos
Eletroquímica/instrumentação , Espaço Extracelular/metabolismo , Shewanella/citologia , Shewanella/metabolismo , Cianetos/farmacologia , Eletrodos , Transporte de Elétrons/efeitos dos fármacos , Espaço Extracelular/efeitos dos fármacos , Mononucleotídeo de Flavina/metabolismo , Ácido Láctico/metabolismo , Shewanella/efeitos dos fármacos
16.
J Glob Antimicrob Resist ; 14: 65-67, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29933118

RESUMO

OBJECTIVES: Shewanella algae is an environmental marine bacterium and an emerging opportunistic human pathogen. Moreover, there are increasing reports of strains showing multidrug resistance, particularly carbapenem-resistant isolates. Although S. algae has been found in bivalve shellfish aquaculture, there is very little genome-wide data on resistance determinants in S. algae from shellfish. The aim of this study was to determine the whole genome sequence of carbapenem-resistant S. algae strain AC isolated from small abalone in Taiwan. METHODS: Bacterial genomic DNA was sequenced using an Illumina MiSeq platform with 250-bp paired-end reads. De novo genome assembly was performed using Velvet v.1.2.07. The whole genome was annotated and several candidate genes for antimicrobial resistance were identified. RESULTS: The genome size was calculated at 4751156bp, with a mean G+C content of 53.09%. A total of 4164 protein-coding sequences, 7 rRNAs, 85 tRNAs and 5 non-coding RNAs were identified. The genome contains genes associated with resistance to ß-lactams, trimethoprim, tetracycline, colistin and quinolones. Multiple efflux pump genes were also detected. CONCLUSION: Small abalone is a potential source of foodborne drug-resistant S. algae. The genome sequence of carbapenem-resistant S. algae strain AC isolated from small abalone will provide valuable information for further study of the dissemination of resistance genes at the human-animal interface.


Assuntos
Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Frutos do Mar/microbiologia , Shewanella/efeitos dos fármacos , Shewanella/genética , Animais , DNA Bacteriano/genética , Testes de Sensibilidade Microbiana , Fatores R/genética , Análise de Sequência de DNA , Taiwan , Sequenciamento Completo do Genoma , beta-Lactamases/genética
17.
Artigo em Inglês | MEDLINE | ID: mdl-29038283

RESUMO

Shewanella spp. constitute a reservoir of antibiotic resistance determinants. In a bile sample, we identified three extended-spectrum-ß-lactamase (ESBL)-producing bacteria (Escherichia coli, Klebsiella pneumoniae, and Shewanella sp. strain JAB-1) isolated from a child suffering from cholangitis. Our objectives were to characterize the genome and the resistome of the first ESBL-producing isolate of the genus Shewanella and determine whether plasmidic exchange occurred between the three bacterial species. Bacterial isolates were characterized using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), standard biochemical tools, and antimicrobial susceptibility testing. Shewanella sp. JAB-1 and ESBL gene-encoding plasmids were characterized using PacBio and Illumina whole-genome sequencing, respectively. The Shewanella sp. JAB-1 chromosome-encoded OXA-48 variant was cloned and functionally characterized. Whole-genome sequencing (WGS) of the Shewanella sp. clinical isolate JAB-1 revealed the presence of a 193-kb plasmid belonging to the IncA/C incompatibility group and harboring two ESBL genes, blaCTX-M-15 and blaSHV-2ablaCTX-M-15 gene-carrying plasmids belonging to the IncY and IncR incompatibility groups were also found in the E. coli and K. pneumoniae isolates from the same patient, respectively. A comparison of the blaCTX-M-15 genetic environment indicated the independent origin of these plasmids and dismissed in vivo transfers. Furthermore, characterization of the resistome of Shewanella sp. JAB-1 revealed the presence of a chromosome-carried blaOXA-535 gene, likely the progenitor of the plasmid-carried blaOXA-436 gene, a novel blaOXA-48-like gene. The expression of blaOXA-535 in E. coli showed the carbapenem-hydrolyzing activity of OXA-535. The production of OXA-535 in Shewanella sp. JAB-1 could be evidenced using molecular and immunoenzymatic tests, but not with biochemical tests that monitor carbapenem hydrolysis. In this study, we have identified a CTX-M-15-producing Shewanella species that was responsible for a hepatobiliary infection and that is likely the progenitor of OXA-436, a novel plasmid-encoded OXA-48-like class D carbapenemase.


Assuntos
Plasmídeos/genética , Shewanella/genética , beta-Lactamases/genética , Antibacterianos/farmacologia , Criança , Colangite/microbiologia , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Feminino , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Shewanella/efeitos dos fármacos
18.
Int J Antimicrob Agents ; 51(3): 340-348, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28666748

RESUMO

Chromosome-encoded beta-lactamases of Shewanella spp. have been indicated as probable progenitors of blaOXA-48-like genes. However, these have been detected in few Shewanella spp. and dissemination mechanisms are unclear. Thus, our main objective was to confirm the role of Shewanella species as progenitors of blaOXA-48-like genes. In silico analysis of Shewanella genomes was performed to detect blaOXA-48-like genes and context, and 43 environmental Shewanella spp. were characterised. Clonal relatedness was determined by BOX-PCR. Phylogenetic affiliation was assessed by 16S rDNA and gyrB sequencing. Antibiotic susceptibility phenotypes were determined. The blaOXA-48-like genes and genetic context were inspected by PCR, hybridisation and sequence analysis. Gene variants were cloned in Escherichia coli and MICs were determined. Shewanella isolates were screened for integrons, plasmids and insertion sequences. Analysis of Shewanella spp. genomes showed that putative blaOXA-48-like is present in the majority and in an identical context. Isolates presenting unique BOX profiles affiliated with 11 Shewanella spp. blaOXA-48-like genes were detected in 22 isolates from 6 species. Genes encoded enzymes identical to OXA-48, OXA-204, OXA-181, and 7 new variants differing from OXA-48 from 2 to 82 amino acids. IS1999 was detected in 24 isolates, although not in the vicinity of blaOXA-48 genes. Recombinant E. coli strains presented altered MICs. The presence/absence of blaOXA-48-like genes was species-related. Gene variants encoded enzymes with hydrolytic spectra similar to OXA-48-like from non-shewanellae. From the mobile elements previously described in association with blaOXA-48-like genes, only the IS1999 was found in Shewanella, which indicates its relevance in blaOXA-48-like genes transfer to other hosts.


Assuntos
Variação Biológica da População , Transferência Genética Horizontal , Variação Genética , Shewanella/efeitos dos fármacos , Shewanella/genética , Resistência beta-Lactâmica , beta-Lactamases/genética , Análise por Conglomerados , DNA Girase/genética , Elementos de DNA Transponíveis , Genótipo , Humanos , Integrons , Testes de Sensibilidade Microbiana , Hibridização de Ácido Nucleico , Plasmídeos , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Homologia de Sequência , beta-Lactamases/classificação
19.
PLoS One ; 12(11): e0188516, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29166414

RESUMO

The chromate efflux pump encoding gene chrASO was identified on the chromosome of Shewanella oneidensis MR1. Although chrASO is expressed without chromate, its expression level increases when Cr(VI) is added. When deleted, the resulting mutant ΔchrASO exhibits a chromate sensitive phenotype compared to that of the wild-type strain. Interestingly, heterologous expression of chrASO in E. coli confers resistance to high chromate concentration. Moreover, expression of chrASO in S. oneidensis and E. coli significantly improves Cr(VI) reduction. This effect could result either from extracytoplasmic chromate reduction or from a better cell survival leading to enhanced Cr(VI) reduction.


Assuntos
Proteínas de Bactérias/metabolismo , Cromatos/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Shewanella/metabolismo , Proteínas de Bactérias/genética , Cromossomos Bacterianos/metabolismo , Escherichia coli , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genes Bacterianos , Oxirredução/efeitos dos fármacos , Filogenia , Shewanella/efeitos dos fármacos , Shewanella/genética
20.
PLoS One ; 12(11): e0188081, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29176835

RESUMO

Omega-3 fatty acids are products of secondary metabolism, essential for growth and important for human health. Although there are numerous reports of bacterial production of omega-3 fatty acids, less information is available on the biotechnological production of these compounds from bacteria. The production of eicosapentaenoic acid (EPA, 20:5ω3) by a new species of marine bacteria Shewanella electrodiphila MAR441T was investigated under different fermentation conditions. This strain produced a high percentage (up to 26%) of total fatty acids and high yields (mg / g of biomass) of EPA at or below the optimal growth temperature. At higher growth temperatures these values decreased greatly. The amount of EPA produced was affected by the carbon source, which also influenced fatty acid composition. This strain required Na+ for growth and EPA synthesis and cells harvested at late exponential or early stationary phase had a higher EPA content. Both the highest amounts (20 mg g-1) and highest percent EPA content (18%) occurred with growth on L-proline and (NH4)2SO4. The addition of cerulenin further enhanced EPA production to 30 mg g-1. Chemical mutagenesis using NTG allowed the isolation of mutants with improved levels of EPA content (from 9.7 to 15.8 mg g-1) when grown at 15°C. Thus, the yields of EPA could be substantially enhanced without the need for recombinant DNA technology, often a commercial requirement for food supplement manufacture.


Assuntos
Organismos Aquáticos/metabolismo , Ácido Eicosapentaenoico/biossíntese , Oceanos e Mares , Shewanella/metabolismo , Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/crescimento & desenvolvimento , Biomassa , Carbono/farmacologia , Cerulenina/farmacologia , Mutação/genética , Nitrogênio/farmacologia , Fosfolipídeos/metabolismo , Shewanella/efeitos dos fármacos , Shewanella/crescimento & desenvolvimento , Fatores de Tempo
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