scholarly journals Interplay between the Zur Regulon Components and Metal Resistance inCupriavidus metallidurans

2019 ◽  
Vol 201 (15) ◽  
Author(s):  
Lucy Bütof ◽  
Cornelia Große ◽  
Hauke Lilie ◽  
Martin Herzberg ◽  
Dietrich H. Nies
Keyword(s):  
Metal Resistance ◽  
Zinc Homeostasis ◽  
Transport Systems ◽  
Starvation Response ◽  
Content Type ◽  
Resistance Factors ◽  
Cupriavidus Metallidurans ◽  
Dependent Protein ◽  
Zinc Storage ◽  
Physiological And Biochemical

ABSTRACTThe Zur regulon is central to zinc homeostasis in the zinc-resistant bacteriumCupriavidus metallidurans. It comprises the transcription regulator Zur, the zinc importer ZupT, and three members of the COG0523 family of metal-chaperoning G3E-type GTPases, annotated as CobW1, CobW2, and CobW3. The operon structures of thezurandcobW1loci were determined. To analyze the interplay between the Zur regulon components and metal resistance, deletion mutants were constructed from the wild-type strain CH34 and various other strains. The Zur regulon components interacted with the plasmid-encoded and chromosomally encoded metal resistance factors to acquire metals from complexes of EDTA and for homeostasis of and resistance to zinc, nickel, cobalt, and cadmium. The three G3E-type GTPases were characterized in more detail. CobW1 bound only 1 Zn atom per mol of protein with a stability constant slightly above that of 2-carboxy-2′-hydroxy-5′-sulfoformazylbenzene (Zincon) and an additional 0.5 Zn with low affinity. The CobW1 system was necessary to obtain metals from EDTA complexes. The GTPase CobW2 is a zinc storage compound and bound 0.5 to 1.5 Zn atoms tightly and up to 6 more with lower affinity. The presence of MgGTP unfolded the protein partially. CobW3 had no GTPase activity and equilibrated metal import by ZupT with that of the other metal transport systems. It sequestered 8 Zn atoms per mol with decreasing affinity. The three CobWs bound to the metal-dependent protein FolEIB2, which is encoded directly downstream ofcobW1. This demonstrated an important contribution of the Zur regulon components to metal homeostasis inC. metallidurans.IMPORTANCEZinc is an important transition metal cation and is present as an essential component in many enzymes, such as RNA polymerase. As with other transition metals, zinc is also toxic at higher concentrations so that living cells have to maintain strict control of their zinc homeostasis. Members of the COG0523 family of metal-chaperoning GE3-type GTPases exist in archaea, bacteria, and eucaryotes, including humans, and they may be involved in delivery of zinc to thousands of different proteins. We used a combination of molecular, physiological, and biochemical methods to demonstrate the important but diverse functions of COG0523 proteins inC. metallidurans, which are produced as part of the Zur-controlled zinc starvation response in this bacterium.

scholarly journals The Components of the Unique Zur Regulon of Cupriavidus metallidurans Mediate Cytoplasmic Zinc Handling

2017 ◽  
Vol 199 (21) ◽  
Author(s):  
Lucy Bütof ◽  
Christopher Schmidt-Vogler ◽  
Martin Herzberg ◽  
Cornelia Große ◽  
Dietrich H. Nies
Keyword(s):  
Consensus Sequence ◽  
Regulatory Region ◽  
Metal Resistance ◽  
Resistant Bacterium ◽  
Zinc Homeostasis ◽  
Mineral Salts ◽  
Content Type ◽  
Zip Family ◽  
Cupriavidus Metallidurans ◽  
Zinc Concentrations

ABSTRACT Zinc is an essential trace element, yet it is toxic at high concentrations. In the betaproteobacterium Cupriavidus metallidurans, the highly efficient removal of surplus zinc from the periplasm is responsible for the outstanding metal resistance of the organism. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans has the secondary zinc importer ZupT of the zinc-regulated transporter, iron-regulated transporter (ZRT/IRT)-like protein (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes with exposure to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δzur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region by use of a truncation assay. The motif was used to predict possible Zur boxes upstream of Zur regulon members. The binding of Zur to these boxes was confirmed. Two Zur boxes upstream of the cobW 1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW 1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW 2, cobW 3, and zupT permitted both low expression levels of these genes and their upregulation under conditions of zinc starvation. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans, where the periplasm is responsible for the removal of surplus zinc, cytoplasmic components are responsible for the management of zinc as an essential cofactor, and the two compartments are connected by ZupT. IMPORTANCE Elucidating zinc homeostasis is necessary for understanding both host-pathogen interactions and the performance of free-living bacteria in their natural environments. Escherichia coli acquires zinc under conditions of low zinc concentrations via the Zur-controlled ZnuABC importer of the ABC superfamily, and this was also the paradigm for other bacteria. In contrast, the heavy-metal-resistant bacterium C. metallidurans achieves high tolerance to zinc through sophisticated zinc handling and efflux systems operating on periplasmic zinc ions, so that removal of surplus zinc is a periplasmic feature in this bacterium. It is shown here that this process is augmented by the management of zinc by cytoplasmic zinc chaperones, whose synthesis is controlled by the Zur regulator. This demonstrates a new mechanism, involving compartmentalization, for organizing zinc homeostasis.

scholarly journals Genome Sequence and Mutational Analysis of Plant-Growth-Promoting Bacterium Agrobacterium tumefaciens CCNWGS0286 Isolated from a Zinc-Lead Mine Tailing

2012 ◽  
Vol 78 (15) ◽  
pp. 5384-5394 ◽  
Author(s):  
Xiuli Hao ◽  
Pin Xie ◽  
Laurel Johnstone ◽  
Susan J. Miller ◽  
Christopher Rensing ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Plant Growth ◽  
Genome Sequence ◽  
Metal Resistance ◽  
Zinc Homeostasis ◽  
Dominant Factor ◽  
Content Type ◽  
Iaa Production ◽  
Plant Growth Promoting ◽  
Growth Promoting

ABSTRACTThe plant-growth-promoting bacteriumAgrobacterium tumefaciensCCNWGS0286, isolated from the nodules ofRobinia pseudoacaciagrowing in zinc-lead mine tailings, both displayed high metal resistance and enhanced the growth ofRobiniaplants in a metal-contaminated environment. Our goal was to determine whether bacterial metal resistance or the capacity to produce phytohormones had a larger impact on the growth of host plants under zinc stress. Eight zinc-sensitive mutants and one zinc-sensitive mutant with reduced indole-3-acetic acid (IAA) production were obtained by transposon mutagenesis. Analysis of the genome sequence and of transcription via reverse transcriptase PCR (RT-PCR) combined with transposon gene disruptions revealed that ZntA-4200 and the transcriptional regulator ZntR1 played important roles in the zinc homeostasis ofA. tumefaciensCCNWGS0286. In addition, interruption of a putative oligoketide cyclase/lipid transport protein reduced IAA synthesis and also showed reduced zinc and cadmium resistance but had no influence on copper resistance. In greenhouse studies,R. pseudoacaciainoculated withA. tumefaciensCCNWGS0286 displayed a significant increase in biomass production over that without inoculation, even in a zinc-contaminated environment. Interestingly, the differences in plant biomass improvement amongA. tumefaciensCCNWGS0286,A. tumefaciensC58, and zinc-sensitive mutants 12-2 (zntA::Tn5) and 15-6 (low IAA production) revealed that phytohormones, rather than genes encoding zinc resistance determinants, were the dominant factor in enhancing plant growth in contaminated soil.

scholarly journals Dual Zinc Transporter Systems in Vibrio cholerae Promote Competitive Advantages over Gut Microbiome

2015 ◽  
Vol 83 (10) ◽  
pp. 3902-3908 ◽  
Author(s):  
Ying Sheng ◽  
Fenxia Fan ◽  
Owen Jensen ◽  
Zengtao Zhong ◽  
Biao Kan ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Gene Clusters ◽  
Bioinformatic Analysis ◽  
Zinc Transporter ◽  
Zinc Homeostasis ◽  
Transport Systems ◽  
Growth Defect ◽  
Dependent Manner ◽  
Content Type ◽  
Transporter Systems

Zinc is an essential trace metal required for numerous cellular processes in all forms of life. In order to maintain zinc homeostasis, bacteria have developed several transport systems to regulate its uptake. In this study, we investigated zinc transport systems in the enteric pathogenVibrio cholerae, the causative agent of cholera. Bioinformatic analysis predicts that two gene clusters, VC2081 to VC2083 (annotated as zinc utilization genesznuABC) and VC2551 to VC2555 (annotated aszinc-regulatedgeneszrgABCDE), are regulated by the putative zinc uptake regulator Zur. Using promoter reporter and biochemical assays, we confirmed that Zur repressesznuABCandzrgABCDEpromoters in a Zn2+-dependent manner. Under Zn2+-limiting conditions, we found that mutations in either theznuABCorzrgABCDEgene cluster affect bacterial growth, withznuABCmutants displaying a more severe growth defect, suggesting that both ZnuABC and ZrgABCDE are involved in Zn2+uptake and that ZnuABC plays the predominant role. Furthermore, we reveal that ZnuABC and ZrgABCDE are important forV. choleraecolonization in both infant and adult mouse models, particularly in the presence of other intestinal microbiota. Collectively, our studies indicate that these two zinc transporter systems play vital roles in maintaining zinc homeostasis duringV. choleraegrowth and pathogenesis.

scholarly journals Endopeptidase Regulation as a Novel Function of the Zur-Dependent Zinc Starvation Response

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shannon G. Murphy ◽  
Laura Alvarez ◽  
Myfanwy C. Adams ◽  
Shuning Liu ◽  
Joshua S. Chappie ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Growth ◽  
Vibrio Cholerae ◽  
Zinc Homeostasis ◽  
Regulatory Control ◽  
Gram Negative Bacteria ◽  
Starvation Response ◽  
Gram Negative ◽  
Content Type ◽  
Antibiotic Development

ABSTRACTThe cell wall is a strong, yet flexible, meshwork of peptidoglycan (PG) that gives a bacterium structural integrity. To accommodate a growing cell, the wall is remodeled by both PG synthesis and degradation.Vibrio choleraeencodes a group of three nearly identical zinc-dependent endopeptidases (EPs) that are predicted to hydrolyze PG to facilitate cell growth. Two of these (ShyA and ShyC) are conditionally essential housekeeping EPs, while the third (ShyB) is not expressed under standard laboratory conditions. To investigate the role of ShyB, we conducted a transposon screen to identify mutations that activateshyBtranscription. We found thatshyBis induced as part of the Zur-mediated zinc starvation response, a mode of regulation not previously reported for cell wall lytic enzymes.In vivo, ShyB alone was sufficient to sustain cell growth in low-zinc environments.In vitro, ShyB retained itsd,d-endopeptidase activity against purified sacculi in the presence of the metal chelator EDTA at concentrations that inhibit ShyA and ShyC. This insensitivity to metal chelation is likely what enables ShyB to substitute for other EPs during zinc starvation. Our survey of transcriptomic data from diverse bacteria identified other candidate Zur-regulated EPs, suggesting that this adaptation to zinc starvation is employed by other Gram-negative bacteria.IMPORTANCEBacteria encode a variety of adaptations that enable them to survive during zinc starvation, a condition which is encountered both in natural environments and inside the human host. InVibrio cholerae, the causative agent of the diarrheal disease cholera, we have identified a novel member of this zinc starvation response, a cell wall hydrolase that retains function and is conditionally essential for cell growth in low-zinc environments. Other Gram-negative bacteria contain homologs that appear to be under similar regulatory control. These findings are significant because they represent, to our knowledge, the first evidence that zinc homeostasis influences cell wall turnover. Anti-infective therapies commonly target the bacterial cell wall; therefore, an improved understanding of how the cell wall adapts to host-induced zinc starvation could lead to new antibiotic development. Such therapeutic interventions are required to combat the rising threat of drug-resistant infections.

The importance of public support in the implementation of green transportation in smart cities using smart vehicle bicycle communication transport

2020 ◽  
Vol 38 (5/6) ◽  
pp. 997-1011
Author(s):  
Ning Li ◽  
Parthasarathy R. ◽  
Harshila H. Padwal
Keyword(s):  
Smart Cities ◽  
Optimization Technique ◽  
Public Support ◽  
Weather Conditions ◽  
Transport Systems ◽  
Content Type ◽  
Signaling Systems ◽  
Traffic Conditions ◽  
Green Transportation ◽  
Smart Vehicle

Purpose Smart mobility is a major guideline in the development of Smart Cities’ transport systems and management. The issue of transition into green, secure and sustainable transport modes, such as using bicycles, should be implemented in this case, along with the subjectivism of management. Design/methodology/approach The proposed technology reflects the Smart Bicycle vehicle model, which tracks cyclists and weather conditions and turns to electric motors in critical circumstances. Findings This reduces the physical load and battery consumption of cyclists which affects the Smart Cities’ ecology positively. Originality/value In Smart Vehicle Bicycle Communication Transport, the vehicle movement optimization technique is used for traffic scenarios to analyze traffic signaling systems that give better results in variable and dense traffic conditions.

scholarly journals Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance

2016 ◽  
Vol 198 (7) ◽  
pp. 1087-1100 ◽  
Author(s):  
Gursonika Binepal ◽  
Kamal Gill ◽  
Paula Crowley ◽  
Martha Cordova ◽  
L. Jeannine Brady ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Streptococcus Mutans ◽  
Transport System ◽  
Biofilm Formation ◽  
Cellular Response ◽  
Pathogenic Bacteria ◽  
Transport Systems ◽  
Content Type ◽  
Growth And Survival ◽  
Dental Biofilm

ABSTRACTPotassium (K+) is the most abundant cation in the fluids of dental biofilm. The biochemical and biophysical functions of K+and a variety of K+transport systems have been studied for most pathogenic bacteria but not for oral pathogens. In this study, we establish the modes of K+acquisition inStreptococcus mutansand the importance of K+homeostasis for its virulence attributes. TheS. mutansgenome harbors four putative K+transport systems that included two Trk-like transporters (designated Trk1 and Trk2), one glutamate/K+cotransporter (GlnQHMP), and a channel-like K+transport system (Kch). Mutants lacking Trk2 had significantly impaired growth, acidogenicity, aciduricity, and biofilm formation. [K+] less than 5 mM eliminated biofilm formation inS. mutans. The functionality of the Trk2 system was confirmed by complementing anEscherichia coliTK2420 mutant strain, which resulted in significant K+accumulation, improved growth, and survival under stress. Taken together, these results suggest that Trk2 is the main facet of the K+-dependent cellular response ofS. mutansto environment stresses.IMPORTANCEBiofilm formation and stress tolerance are important virulence properties of caries-causingStreptococcus mutans. To limit these properties of this bacterium, it is imperative to understand its survival mechanisms. Potassium is the most abundant cation in dental plaque, the natural environment ofS. mutans. K+is known to function in stress tolerance, and bacteria have specialized mechanisms for its uptake. However, there are no reports to identify or characterize specific K+transporters inS. mutans. We identified the most important system for K+homeostasis and its role in the biofilm formation, stress tolerance, and growth. We also show the requirement of environmental K+for the activity of biofilm-forming enzymes, which explains why such high levels of K+would favor biofilm formation.

scholarly journals Coxiella burnetii Alters Cyclic AMP-Dependent Protein Kinase Signaling during Growth in Macrophages

2012 ◽  
Vol 80 (6) ◽  
pp. 1980-1986 ◽  
Author(s):  
Laura J. MacDonald ◽  
Richard C. Kurten ◽  
Daniel E. Voth
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Coxiella Burnetii ◽  
Alveolar Macrophages ◽  
Q Fever ◽  
Parasitophorous Vacuole ◽  
Dependent Protein Kinase ◽  
Content Type ◽  
Bacterial Agent ◽  
Dependent Protein

ABSTRACTCoxiella burnetiiis the bacterial agent of human Q fever, an acute, flu-like illness that can present as chronic endocarditis in immunocompromised individuals. Following aerosol-mediated transmission,C. burnetiireplicates in alveolar macrophages in a unique phagolysosome-like parasitophorous vacuole (PV) required for survival. The mechanisms ofC. burnetiiintracellular survival are poorly defined and a recent Q fever outbreak in the Netherlands emphasizes the need for better understanding this unique host-pathogen interaction. We recently demonstrated that inhibition of host cyclic AMP-dependent protein kinase (PKA) activity negatively impacts PV formation. In the current study, we confirmed PKA involvement in PV biogenesis and probed the role of PKA signaling duringC. burnetiiinfection of macrophages. Using PKA-specific inhibitors, we found the kinase was needed for biogenesis of prototypical PV andC. burnetiireplication. PKA and downstream targets were differentially phosphorylated throughout infection, suggesting prolonged regulation of the pathway. Importantly, the pathogen actively triggered PKA activation, which was also required for PV formation by virulentC. burnetiiisolates during infection of primary human alveolar macrophages. A subset of PKA-specific substrates were differentially phosphorylated duringC. burnetiiinfection, suggesting the pathogen uses PKA signaling to control distinct host cell responses. Collectively, the current results suggest a versatile role for PKA inC. burnetiiinfection and indicate virulent organisms usurp host kinase cascades for efficient intracellular growth.

scholarly journals Target (MexB)- and Efflux-Based Mechanisms Decreasing the Effectiveness of the Efflux Pump Inhibitor D13-9001 in Pseudomonas aeruginosa PAO1: Uncovering a New Role for MexMN-OprM in Efflux of β-Lactams and a Novel Regulatory Circuit (MmnRS) Controlling MexMN Expression

2018 ◽  
Vol 63 (2) ◽  
pp. e01718-18 ◽  
Author(s):  
Srijan Ranjitkar ◽  
Adriana K. Jones ◽  
Mina Mostafavi ◽  
Zachary Zwirko ◽  
Oleg Iartchouk ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Response Regulator ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Rna Seq ◽  
Efflux Pump Inhibitor ◽  
Content Type ◽  
Regulatory Circuit ◽  
Outer Membrane Channel

ABSTRACT Efflux pumps contribute to antibiotic resistance in Gram-negative pathogens. Correspondingly, efflux pump inhibitors (EPIs) may reverse this resistance. D13-9001 specifically inhibits MexAB-OprM in Pseudomonas aeruginosa. Mutants with decreased susceptibility to MexAB-OprM inhibition by D13-9001 were identified, and these fell into two categories: those with alterations in the target MexB (F628L and ΔV177) and those with an alteration in a putative sensor kinase of unknown function, PA1438 (L172P). The alterations in MexB were consistent with reported structural studies of the D13-9001 interaction with MexB. The PA1438L172P alteration mediated a >150-fold upregulation of MexMN pump gene expression and a >50-fold upregulation of PA1438 and the neighboring response regulator gene, PA1437. We propose that these be renamed mmnR and mmnS for MexMN regulator and MexMN sensor, respectively. MexMN was shown to partner with the outer membrane channel protein OprM and to pump several β-lactams, monobactams, and tazobactam. Upregulated MexMN functionally replaced MexAB-OprM to efflux these compounds but was insusceptible to inhibition by D13-9001. MmnSL172P also mediated a decrease in susceptibility to imipenem and biapenem that was independent of MexMN-OprM. Expression of oprD, encoding the uptake channel for these compounds, was downregulated, suggesting that this channel is also part of the MmnSR regulon. Transcriptome sequencing (RNA-seq) of cells encoding MmnSL172P revealed, among other things, an interrelationship between the regulation of mexMN and genes involved in heavy metal resistance.

scholarly journals Cupriavidus metallidurans Strains with Different Mobilomes and from Distinct Environments Have Comparable Phenomes

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 507 ◽  
Author(s):  
Rob Van Houdt ◽  
Ann Provoost ◽  
Ado Van Assche ◽  
Natalie Leys ◽  
Bart Lievens ◽  
...  
Keyword(s):  
Genomic Island ◽  
Space Station ◽  
Nutrient Utilization ◽  
Metal Resistance ◽  
Human Infection ◽  
Abietane Diterpenoids ◽  
Cupriavidus Metallidurans ◽  
Mobile Gene ◽  
Phenotype Microarrays ◽  
The Impact

Cupriavidus metallidurans has been mostly studied because of its resistance to numerous heavy metals and is increasingly being recovered from other environments not typified by metal contamination. They host a large and diverse mobile gene pool, next to their native megaplasmids. Here, we used comparative genomics and global metabolic comparison to assess the impact of the mobilome on growth capabilities, nutrient utilization, and sensitivity to chemicals of type strain CH34 and three isolates (NA1, NA4 and H1130). The latter were isolated from water sources aboard the International Space Station (NA1 and NA4) and from an invasive human infection (H1130). The mobilome was expanded as prophages were predicted in NA4 and H1130, and a genomic island putatively involved in abietane diterpenoids metabolism was identified in H1130. An active CRISPR-Cas system was identified in strain NA4, providing immunity to a plasmid that integrated in CH34 and NA1. No correlation between the mobilome and isolation environment was found. In addition, our comparison indicated that the metal resistance determinants and properties are conserved among these strains and thus maintained in these environments. Furthermore, all strains were highly resistant to a wide variety of chemicals, much broader than metals. Only minor differences were observed in the phenomes (measured by phenotype microarrays), despite the large difference in mobilomes and the variable (shared by two or three strains) and strain-specific genomes.

scholarly journals Differential Metabolism of Exopolysaccharides from Probiotic Lactobacilli by the Human Gut Symbiont Bacteroides thetaiotaomicron

2015 ◽  
Vol 81 (12) ◽  
pp. 3973-3983 ◽  
Author(s):  
Alicia Lammerts van Bueren ◽  
Aakanksha Saraf ◽  
Eric C. Martens ◽  
Lubbert Dijkhuizen
Keyword(s):  
Gastrointestinal Tract ◽  
Carbohydrate Metabolism ◽  
Lactobacillus Reuteri ◽  
Bacterial Species ◽  
Transport Systems ◽  
Bacteroides Thetaiotaomicron ◽  
Human Gut ◽  
Positive Health ◽  
Content Type ◽  
Commensal Species

ABSTRACTProbiotic microorganisms are ingested as food or supplements and impart positive health benefits to consumers. Previous studies have indicated that probiotics transiently reside in the gastrointestinal tract and, in addition to modulating commensal species diversity, increase the expression of genes for carbohydrate metabolism in resident commensal bacterial species. In this study, it is demonstrated that the human gut commensal speciesBacteroides thetaiotaomicronefficiently metabolizes fructan exopolysaccharide (EPS) synthesized by probioticLactobacillus reuteristrain 121 while only partially degrading reuteran and isomalto/malto-polysaccharide (IMMP) α-glucan EPS polymers.B. thetaiotaomicronmetabolized these EPS molecules via the activation of enzymes and transport systems encoded by dedicated polysaccharide utilization loci specific for β-fructans and α-glucans. Reduced metabolism of reuteran and IMMP α-glucan EPS molecules may be due to reduced substrate binding by components of the starch utilization system (sus). This study reveals that microbial EPS substrates activate genes for carbohydrate metabolism inB. thetaiotaomicronand suggests that microbially derived carbohydrates provide a carbohydrate-rich reservoir forB. thetaiotaomicronnutrient acquisition in the gastrointestinal tract.

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