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the effect of imipenem and diffusible signaling factors on the secretion of outer membrane vesicles and associated ax21 proteins in stenotrophomonas maltophilia.outer membrane vesicles (omvs) are small nanoscale structures that are secreted by bacteria and that can carry nucleic acids, proteins, and small metabolites. they can mediate intracellular communication and play a role in virulence. in this study, we show that treatment with the β-lactam antibiotic imipenem leads to a dramatic increase in the secretion of outer membrane vesicles in the nosocomial pathogen stenotrophomonas maltophilia. proteomic analysis of their protein content demonstrated tha ...201525926824
a burkholderia cenocepacia murj (mvin) homolog is essential for cell wall peptidoglycan synthesis and bacterial viability.the cell wall peptidoglycan (pg) of burkholderia cenocepacia, an opportunistic pathogen, has not yet been characterized. however, the b. cenocepacia genome contains homologs of genes encoding pg biosynthetic functions in other bacteria. pg biosynthesis involves the formation of the undecaprenyl-pyrophosphate-linked n-acetyl glucosamine-n-acetyl muramic acid-pentapeptide, known as lipid ii, which is built on the cytosolic face of the cell membrane. lipid ii is then translocated across the membran ...201424688094
crystal structure of bacterial haem importer complex in the inward-facing conformation.pathogenic bacteria remove iron from the haem of host tissues and use it as a catalytic center of many enzymes. haem uptake by pathogenic bacteria is facilitated by the membrane-integrated haem importer, which belongs to the type ii atp-binding cassette (abc) transporter. here we present crystal structures of burkholderia cenocepacia haem importer bhuuv complexed with the periplasmic haem-binding protein bhut and in the absence of bhut. the transmembrane helices of these structures show an inwar ...201627830695
orderly replication and segregation of the four replicons of burkholderia cenocepacia j2315.bacterial genomes typically consist of a single chromosome and, optionally, one or more plasmids. but whole-genome sequencing reveals about ten per-cent of them to be multipartite, with additional replicons which by size and indispensability are considered secondary chromosomes. this raises the questions of how their replication and partition is managed without compromising genome stability and of how such genomes arose. vibrio cholerae, with a 1 mb replicon in addition to its 3 mb chromosome, i ...201627428258
the use of nanoscale visible light-responsive photocatalyst tio2-pt for the elimination of soil-borne pathogens.exposure to the soil-borne pathogens burkholderia pseudomallei and burkholderia cenocepacia can lead to severe infections and even mortality. these pathogens exhibit a high resistance to antibiotic treatments. in addition, no licensed vaccine is currently available. a nanoscale platinum-containing titania photocatalyst (tio(2)-pt) has been shown to have a superior visible light-responsive photocatalytic ability to degrade chemical contaminants like nitrogen oxides. the antibacterial activity of ...201222384003
global changes in gene expression by the opportunistic pathogen burkholderia cenocepacia in response to internalization by murine macrophages.burkholderia cenocepacia is an opportunistic pathogen causing life-threatening infections in patients with cystic fibrosis. the bacterium survives within macrophages by interfering with endocytic trafficking and delaying the maturation of the b. cenocepacia-containing phagosome. we hypothesize that b. cenocepacia undergoes changes in gene expression after internalization by macrophages, inducing genes involved in intracellular survival and host adaptation.201222321740
antibacterial activity of eravacycline (tp-434), a novel fluorocycline, against hospital and community pathogens.eravacycline (tp-434 or 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline) is a novel fluorocycline that was evaluated for antimicrobial activity against panels of recently isolated aerobic and anaerobic gram-negative and gram-positive bacteria. eravacycline showed potent broad-spectrum activity against 90% of the isolates (mic90) in each panel at concentrations ranging from ≤0.008 to 2 μg/ml for all species panels except those of pseudomonas aeruginosa and burkholderia cenocepacia ...201323979750
structural-functional studies of burkholderia cenocepacia d-glycero-β-d-manno-heptose 7-phosphate kinase (hlda) and characterization of inhibitors with antibiotic adjuvant and antivirulence properties.as an essential constituent of the outer membrane of gram-negative bacteria, lipopolysaccharide contributes significantly to virulence and antibiotic resistance. the lipopolysaccharide biosynthetic pathway therefore serves as a promising therapeutic target for antivirulence drugs and antibiotic adjuvants. here we report the structural-functional studies of d-glycero-β-d-manno-heptose 7-phosphate kinase (hlda), an absolutely conserved enzyme in this pathway, from burkholderia cenocepacia. hlda is ...201223256532
a functional orit in the ptw plasmid of burkholderia cenocepacia can be recognized by the r388 relaxase trwc.burkholderia cenocepacia is both a plant pathogen and the cause of serious opportunistic infections, particularly in cystic fibrosis patients. b. cenocepacia k56-2 harbors a native plasmid named ptw for its involvement in the plant tissue watersoaking phenotype. ptw has also been reported to be important for survival in human cells. interestingly, the presence of ptwc, a homolog of the conjugative relaxase trwc of plasmid r388, suggests a possible function for ptw in conjugative dna transfer. th ...201627200362
activation of human toll-like receptor 4 (tlr4)·myeloid differentiation factor 2 (md-2) by hypoacylated lipopolysaccharide from a clinical isolate of burkholderia cenocepacia.lung infection by burkholderia species, in particular burkholderia cenocepacia, accelerates tissue damage and increases post-lung transplant mortality in cystic fibrosis patients. host-microbe interplay largely depends on interactions between pathogen-specific molecules and innate immune receptors such as toll-like receptor 4 (tlr4), which recognizes the lipid a moiety of the bacterial lipopolysaccharide (lps). the human tlr4·myeloid differentiation factor 2 (md-2) lps receptor complex is strong ...201526160169
antibiotic resistance in burkholderia species.the genus burkholderia comprises metabolically diverse and adaptable gram-negative bacteria, which thrive in often adversarial environments. a few members of the genus are prominent opportunistic pathogens. these include burkholderia mallei and burkholderia pseudomallei of the b. pseudomallei complex, which cause glanders and melioidosis, respectively. burkholderia cenocepacia, burkholderia multivorans, and burkholderia vietnamiensis belong to the burkholderia cepacia complex and affect mostly c ...201627620956
broad-spectrum anti-biofilm peptide that targets a cellular stress response.bacteria form multicellular communities known as biofilms that cause two thirds of all infections and demonstrate a 10 to 1000 fold increase in adaptive resistance to conventional antibiotics. currently, there are no approved drugs that specifically target bacterial biofilms. here we identified a potent anti-biofilm peptide 1018 that worked by blocking (p)ppgpp, an important signal in biofilm development. at concentrations that did not affect planktonic growth, peptide treatment completely preve ...201424852171
synthetic cystic fibrosis sputum medium diminishes <i>burkholderia cenocepacia</i> antifungal activity against <i>aspergillus fumigatus</i> independently of phenylacetic acid production.phenylacetic acid (paa), an intermediate of phenylalanine degradation, is emerging as a signal molecule in microbial interactions with the host. in this work, we explore the presence of phenylalanine and paa catabolism in three microbial pathogens of the cystic fibrosis (cf) lung microbiome: <i>pseudomonas aeruginosa</i>, <i>burkholderia cenocepacia</i> and <i>aspergillus fumigatus</i>. while <i>in silico</i> analysis of <i>b. cenocepacia</i> j2315 and <i>a. fumigatus</i> af293 genome sequences ...201728178425
structure of the chlamydia trachomatis immunodominant antigen pgp3.chlamydia trachomatis infection is the most common sexually transmitted bacterial disease. left untreated, it can lead to ectopic pregnancy, pelvic inflammatory disease, and infertility. here we present the structure of the secreted c. trachomatis protein pgp3, an immunodominant antigen and putative virulence factor. the ∼84-kda pgp3 homotrimer, encoded on a cryptic plasmid, consists of globular n- and c-terminal assemblies connected by a triple-helical coiled-coil. the c-terminal domains posses ...201323703617
destruction of opportunistic pathogens via polymer nanoparticle-mediated release of plant-based antimicrobial payloads.the synthesis of antimicrobial thymol/carvacrol-loaded polythioether nanoparticles (nps) via a one-pot, solvent-free miniemulsion thiol-ene photopolymerization process is reported. the active antimicrobial agents, thymol and carvacrol, are employed as "solvents" for the thiol-ene monomer phase in the miniemulsion to enable facile high capacity loading (≈50% w/w), excellent encapsulation efficiencies (>95%), and elimination of all postpolymerization purification processes. the nps serve as high c ...201626946055
accurate identification of members of the burkholderia cepacia complex in cystic fibrosis sputum.the burkholderia cepacia complex (bcc) is a group of closely related species which includes opportunistic pathogens causing chronic respiratory infections in immunocompromised patients, or individuals affected by cystic fibrosis (cf). other burkholderia species causing infection in the cf population are burkholderia gladioli and burkholderia pseudomallei. traditional phenotypic analyses have been demonstrated to be inadequate for reliable identifications of isolates of bcc and b. gladioli. a pan ...201626671758
identification and analysis of genomic islands in burkholderia cenocepacia au 1054 with emphasis on pathogenicity islands.genomic islands (gis) are genomic regions that reveal evidence of horizontal dna transfer. they can code for many functions and may augment a bacterium's adaptation to its host or environment. gis have been identified in strain j2315 of burkholderia cenocepacia, whereas in strain au 1054 there has been no published works on such regions according to our text mining and keyword search in medline.201728347342
phenotypic diversity and genotypic flexibility of burkholderia cenocepacia during long-term chronic infection of cystic fibrosis lungs.chronic bacterial infections of the lung are the leading cause of morbidity and mortality in cystic fibrosis patients. tracking bacterial evolution during chronic infections can provide insights into how host selection pressures-including immune responses and therapeutic interventions-shape bacterial genomes. we carried out genomic and phenotypic analyses of 215 serially collected burkholderia cenocepacia isolates from 16 cystic fibrosis patients, spanning a period of 2-20 yr and a broad range o ...201728325850
peptide modification results in the formation of a dimer with a 60-fold enhanced antimicrobial activity.cationic antimicrobial peptides (camps) occur naturally in numerous organisms and are considered as a class of antibiotics with promising potential against multi-resistant bacteria. herein, we report a strategy that can lead to the discovery of novel small camps with greatly enhanced antimicrobial activity and retained antibiofilm potential. we geared our efforts towards i) the n-terminal cysteine functionalization of a previously reported small synthetic cationic peptide (peptide 1037, krfrirvr ...201728296935
sequential burkholderia cenocepacia isolates from siblings with cystic fibrosis show increased lung cell attachment. 201728294652
antibiotic capture by bacterial lipocalins uncovers an extracellular mechanism of intrinsic antibiotic resistance.the potential for microbes to overcome antibiotics of different classes before they reach bacterial cells is largely unexplored. here we show that a soluble bacterial lipocalin produced by burkholderia cenocepacia upon exposure to sublethal antibiotic concentrations increases resistance to diverse antibiotics in vitro and in vivo these phenotypes were recapitulated by heterologous expression in b. cenocepacia of lipocalin genes from pseudomonas aeruginosa, mycobacterium tuberculosis, and methici ...201728292982
a broad host range tailocin from burkholderia cenocepacia.the burkholderia cepacia complex (bcc) consists of 20 closely related gram-negative bacterial species that are significant pathogens for persons with cystic fibrosis (cf). some bcc strains are highly transmissible and resistant to multiple antibiotics, making infection difficult to treat. a tailocin (phage-tail-like bacteriocin), designated bcetmilo, with broad host range against members of the bcc was identified in burkholderia cenocepacia strain bc0425. sixty-eight percent of bcc representing ...201728258146
evaluation of combination therapy for burkholderia cenocepacia lung infection in different in vitro and in vivo models.burkholderia cenocepacia is an opportunistic pathogen responsible for life-threatening infections in cystic fibrosis patients. b. cenocepacia is extremely resistant towards antibiotics and therapy is complicated by its ability to form biofilms. we investigated the efficacy of an alternative antimicrobial strategy for b. cenocepacia lung infections using in vitro and in vivo models. a screening of the nih clinical collection 1&2 was performed against b. cenocepacia biofilms formed in 96-well micr ...201728248999
biocontrol of burkholderia cepacia complex bacteria and bacterial phytopathogens by bdellovibrio bacteriovorus.bdellovibrio and like organisms are predatory bacteria that have the unusual property of using the cytoplasmic constituents of other gram-negative bacteria as nutrients. these predators may thus provide an alternative approach to the biocontrol of human and plant pathogens. predators were isolated on burkholderia cenocepacia k56-2 and j2315 as prey cells, in enrichment cultures with soil and sewage. three isolates (dm7c, dm8a, and dm11a) were identified as bdellovibrio bacteriovorus on the basis ...201728177793
mouse intestinal niche cells express a distinct α1,2-fucosylated glycan recognized by a lectin from burkholderia cenocepacia. 201728177462
human cystic fibrosis macrophages have defective calcium-dependent protein kinase c activation of the nadph oxidase, an effect augmented by burkholderia cenocepacia.macrophage intracellular pathogen killing is defective in cystic fibrosis (cf), despite abundant production of reactive oxygen species (ros) in lung tissue. burkholderia species can cause serious infection in cf and themselves affect key oxidase components in murine non-cf cells. however, it is unknown whether human cf macrophages have an independent defect in the oxidative burst and whether burkholderia contributes to this defect in terms of assembly of the nadph oxidase complex and subsequent ...201728093527
the lpxl acyltransferase is required for normal growth and penta-acylation of lipid a in burkholderia cenocepacia.lipid a anchors the lipopolysaccharide (lps) to the outer membrane and is usually composed of a hexa-acylated diglucosamine backbone. burkholderia cenocepacia, an opportunistic pathogen, produces a mixture of tetra- and penta-acylated lipid a. "late" acyltransferases add secondary acyl chains to lipid a after the incorporation of four primary acyl chains to the diglucosamine backbone. here, we report that b. cenocepacia has only one late acyltransferase, lpxl (bcal0508), which adds a myristoyl c ...201728085228
cheating fosters species co-existence in well-mixed bacterial communities.explaining the enormous biodiversity observed in bacterial communities is challenging because ecological theory predicts that competition between species occupying the same niche should lead to the exclusion of less competitive community members. competitive exclusion should be particularly strong when species compete for a single limiting resource or live in unstructured habitats that offer no refuge for weaker competitors. here, we describe the 'cheating effect', a form of intra-specific compe ...201728060362
using dendritic cells to evaluate how burkholderia cenocepacia clonal isolates from a chronically infected cystic fibrosis patient subvert immune functions.infection with burkholderia cepacia complex (bcc) bacteria is a threat to cystic fibrosis (cf) patients, commonly leading to a fatal pneumonia, the cepacia syndrome. it causes a massive production of pro-inflammatory cytokines and leucocyte recruitment to airway epithelium without resolving infection and contributing to tissue lesion. to dissect how bcc bacteria subvert the immune response, we developed a co-culture model with human dendritic cells (dcs) and b. cenocepacia clonal variants isolat ...201727987042
mouse intestinal niche cells express a distinct α1,2-fucosylated glycan recognized by a lectin from burkholderia cenocepacia.in this study, we examined the distribution of fucosylated glycans in mouse intestines using a lectin, bc2lcn (n-terminal domain of the lectin bc2l-c from burkholderia cenocepacia), as a probe. bc2lcn is specific for glycans with a terminal fucα1,2galβ1,3-motif and it is a useful marker for discriminating the undifferentiated status of human induced/embryonic stem cells. apparent bc2lcn reactivity was detected in the secretory granules of goblet cells in the ileum but not those in the colon. we ...201627979999
the burkholderia cenocepacia peptidoglycan-associated lipoprotein is involved in epithelial cell attachment and elicitation of inflammation.the burkholderia cepacia complex (bcc) is a group of gram-negative opportunistic pathogens causing infections in people with cystic fibrosis (cf). bcc is highly antibiotic resistant, making conventional antibiotic treatment problematic. the identification of novel targets for anti-virulence therapies should improve therapeutic options for infected cf patients. we previously identified that the peptidoglycan-associated lipoprotein (pal) was immunogenic in bcc infected cf patients; however, its ro ...201727886433
tri- and tetravalent mannoclusters cross-link and aggregate bc2l-a lectin from burkholderia cenocepacia.the opportunistic gram-negative bacterium burkholderia cenocepacia causes lethal infections in cystic fibrosis patients. multivalent mannoside derivatives were prepared as potential inhibitors of lectin bc2l-a, one of the virulence factors deployed by b. cenocepacia in the infection process. an (α1→2)-thio-linked mannobioside mimic bearing an azide functionalized aglycon was conjugated to different multivalent scaffolds such as propargylated calix[4]arenes, methyl gallate and pentaerythritol by ...201727871013
bacterial proteases and haemostasis dysregulation in the cf lung.pathogenic bacteria which chronically colonise the cystic fibrosis (cf) lung produce a number of virulence determinants, including distinct proteolytic activities. the potential role bacterial proteases play on haemostatic dysregulation within the cf lung is, however, poorly defined, despite haemoptysis being a common complication in cf.201727839953
an efficient system for the generation of marked genetic mutants in members of the genus burkholderia.to elucidate the function of a gene in bacteria it is vital that targeted gene inactivation (allelic replacement) can be achieved. allelic replacement is often carried out by disruption of the gene of interest by insertion of an antibiotic-resistance marker followed by subsequent transfer of the mutant allele to the genome of the host organism in place of the wild-type gene. however, due to their intrinsic resistance to many antibiotics only selected antibiotic-resistance markers can be used in ...201727825973
combination antimicrobial susceptibility testing of burkholderia cepacia complex: significance of species.the burkholderia cepacia complex (bcc) is notorious for the life-threatening pulmonary infections it causes in patients with cystic fibrosis. the multidrug-resistant nature of bcc and differing infective bcc species make the design of appropriate treatment regimens challenging. previous synergy studies have failed to take account of the species of bcc isolates. etest methodology was used to facilitate minimum inhibitory concentration (mic) and antimicrobial combination testing on 258 isolates of ...201627665523
competitive growth enhances conditional growth mutant sensitivity to antibiotics and exposes a two-component system as an emerging antibacterial target in burkholderia cenocepacia.chemogenetic approaches to profile an antibiotic mode of action are based on detecting differential sensitivities of engineered bacterial strains in which the antibacterial target (usually encoded by an essential gene) or an associated process is regulated. we previously developed an essential-gene knockdown mutant library in the multidrug-resistant burkholderia cenocepacia by transposon delivery of a rhamnose-inducible promoter. in this work, we used illumina sequencing of multiplex-pcr-amplifi ...201727799222
elevated mirc1/mir17-92 cluster expression negatively regulates autophagy and cftr (cystic fibrosis transmembrane conductance regulator) function in cf macrophages.cystic fibrosis (cf) is a fatal, genetic disorder that critically affects the lungs and is directly caused by mutations in the cf transmembrane conductance regulator (cftr) gene, resulting in defective cftr function. macroautophagy/autophagy is a highly regulated biological process that provides energy during periods of stress and starvation. autophagy clears pathogens and dysfunctional protein aggregates within macrophages. however, this process is impaired in cf patients and cf mice, as their ...201627541364
burkholderia cenocepacia k56-2 trimeric autotransporter adhesin bcaa binds tnfr1 and contributes to induce airway inflammation.chronic lung disease caused by persistent bacterial infections is a major cause of morbidity and mortality in patients with cystic fibrosis (cf). cf pathogens acquire antibiotic resistance, overcome host defenses, and impose uncontrolled inflammation that ultimately may cause permanent damage of lungs' airways. among the multiple cf-associated pathogens, burkholderia cenocepacia and other burkholderia cepacia complex bacteria have become prominent contributors of disease progression. here, we de ...201727684048
burkholderia cenocepacia virulence microevolution in the cf lung: variations on a theme. 201627786605
the temperate burkholderia phage ap3 of the peduovirinae shows efficient antimicrobial activity against b. cenocepacia of the iiia lineage.burkholderia phage ap3 (vb_bcem_ap3) is a temperate virus of the myoviridae and the peduovirinae subfamily (p2likevirus genus). this phage specifically infects multidrug-resistant clinical burkholderia cenocepacia lineage iiia strains commonly isolated from cystic fibrosis patients. ap3 exhibits high pairwise nucleotide identity (61.7 %) to burkholderia phage ks5, specific to the same b. cenocepacia host, and has 46.7-49.5 % identity to phages infecting other species of burkholderia. the lysis c ...201727770178
the fitness effects of spontaneous mutations nearly unseen by selection in a bacterium with multiple chromosomes.mutation accumulation (ma) experiments employ the strategy of minimizing the population size of evolving lineages to greatly reduce effects of selection on newly arising mutations. thus, most mutations fix within ma lines independently of their fitness effects. this approach, more recently combined with genome sequencing, has detailed the rates, spectra, and biases of different mutational processes. however, a quantitative understanding of the fitness effects of mutations virtually unseen by sel ...201627672096
variation of burkholderia cenocepacia virulence potential during cystic fibrosis chronic lung infection.during long-term lung infection in cystic fibrosis (cf) patients, burkholderia cenocepacia faces multiple selective pressures in this highly stressful and fluctuating environment. as a consequence, the initial infecting strain undergoes genetic changes that result in the diversification of genotypes and phenotypes. whether this clonal expansion influences the pathogenic potential is unclear. the virulence potential of 39 sequential b. cenocepacia (reca lineage iiia) isolates, corresponding to 3 ...201627652671
the effect of mutation in the clpx gene on the synthesis of n-acyl-homoserine lactones and other properties of burkholderia cenocepacia 370.in order to study the regulation of n-acyl-homoserine lactones synthesis (ahls, the signal molecules of quorum sensing regulation) in burkholderia cenocepacia strain 370 we obtained mutants with increased ahl production. one of the mutants, named bc-b6, was obtained by tnmod-rkm(r) plasposon mutagenesis. the plasposon insertion was located within the clpx gene encoding the atpase subunit clpx of the clpxp protease. the mutation reduced bacterial virulence in mice intranasal infection. the result ...201727242147
the crystal structure of burkholderia cenocepacia dfsa provides insights into substrate recognition and quorum sensing fatty acid biosynthesis.burkholderia cenocepacia is a major concern among respiratory tract infections in cystic fibrosis patients. this pathogen is particularly difficult to treat because of its high level of resistance to the clinically relevant antimicrobial agents. in b. cenocepacia, the quorum sensing cell-cell communication system is involved in different processes that are important for bacterial virulence, such as biofilm formation and protease and siderophore production. targeting the enzymes involved in this ...201627198181
eradication and phenotypic tolerance of burkholderia cenocepacia biofilms exposed to atmospheric pressure non-thermal plasma.chronic lung infection with bacteria from the burkholderia cepacia complex (bcc), and in particular b. cenocepacia, is associated with significant morbidity and mortality in patients with cystic fibrosis (cf). b. cenocepacia can spread from person to person and exhibits intrinsic broad-spectrum antibiotic resistance. recently, atmospheric pressure non-thermal plasmas (apntps) have gained increasing attention as a novel approach to the prevention and treatment of a variety of hospital-acquired in ...201627179816
a burkholderia type vi effector deamidates rho gtpases to activate the pyrin inflammasome and trigger inflammation.burkholderia cenocepacia is an opportunistic pathogen of the cystic fibrosis lung that elicits a strong inflammatory response. b. cenocepacia employs a type vi secretion system (t6ss) to survive in macrophages by disarming rho-type gtpases, causing actin cytoskeletal defects. here, we identified teca, a non-vgrg t6ss effector responsible for actin disruption. teca and other bacterial homologs bear a cysteine protease-like catalytic triad, which inactivates rho gtpases by deamidating a conserved ...201627133449
in vitro volatile organic compound profiling using gc×gc-tofms to differentiate bacteria associated with lung infections: a proof-of-concept study.chronic pulmonary infections are the principal cause of morbidity and mortality in individuals with cystic fibrosis (cf). due to the polymicrobial nature of these infections, the identification of the particular bacterial species responsible is an essential step in diagnosis and treatment. current diagnostic procedures are time-consuming, and can also be expensive, invasive and unpleasant in the absence of spontaneously expectorated sputum. the development of a rapid, non-invasive methodology ca ...201627120170
lipopolysaccharide modification in gram-negative bacteria during chronic infection.the gram-negative bacterial lipopolysaccharide (lps) is a major component of the outer membrane that plays a key role in host-pathogen interactions with the innate immune system. during infection, bacteria are exposed to a host environment that is typically dominated by inflammatory cells and soluble factors, including antibiotics, which provide cues about regulation of gene expression. bacterial adaptive changes including modulation of lps synthesis and structure are a conserved theme in infect ...201627075488
laboratory evolution of microbial interactions in bacterial biofilms.microbial adaptation is conspicuous in essentially every environment, but the mechanisms of adaptive evolution are poorly understood. studying evolution in the laboratory under controlled conditions can be a tractable approach, particularly when new, discernible phenotypes evolve rapidly. this is especially the case in the spatially structured environments of biofilms, which promote the occurrence and stability of new, heritable phenotypes. further, diversity in biofilms can give rise to nascent ...201627044625
fish oils against burkholderia and pseudomonas aeruginosa: in vitro efficacy and their therapeutic and prophylactic effects on infected galleria mellonella larvae.this study investigates the antimicrobial effects of fish oil-based formulas rich in omega-3 fatty acids (free fatty acids, ethyl esters or triacylglycerols), against cystic fibrosis (cf) pathogens (burkholderia cenocepacia k56-2 and pseudomonas aeruginosa pao1), often resistant to multiple antibiotics.201627012860
an erp57-mediated disulphide exchange promotes the interaction between burkholderia cenocepacia and epithelial respiratory cells.previous studies have demonstrated that extracellular glutathione reduces the ability of the cystic fibrosis pathogen burkholderia cenocepacia to infect primary or immortalized epithelial respiratory cells. we report here that the adhesion and invasion ability of b. cenocepacia is limited also by thiol-oxidizing and disulphide-reducing agents and by protein disulfide isomerase (pdi) inhibitors. pdi inhibitors also reduce the proinflammatory response elicited by cells in response to burkholderia. ...201626879174
activator of g-protein signaling 3-induced lysosomal biogenesis limits macrophage intracellular bacterial infection.many intracellular pathogens cause disease by subverting macrophage innate immune defense mechanisms. intracellular pathogens actively avoid delivery to or directly target lysosomes, the major intracellular degradative organelle. in this article, we demonstrate that activator of g-protein signaling 3 (ags3), an lps-inducible protein in macrophages, affects both lysosomal biogenesis and activity. ags3 binds the gi family of g proteins via its g-protein regulatory (goloco) motif, stabilizing the g ...201626667172
[the effect of introduction of the heterologous gene encoding the n-acyl-homoserine lactonase (aiia) on the properties of burkholderia cenocepacia 370].to study the role of quorum sensing (qs) regulation in the control of the cellular processes of burkholderia cenocepacia 370, plasmid pme6863 was transferred into its cells. the plasmid contains a heterologous gene encoding for aiia n-acyl-homoserine lactonase, which degrades the signaling molecules of the qs system of n-acyl-homoserine lactones (ahl). an absence or reduction of ahl in the culture was revealed with the biosensors chromobacterium violaceum cv026 and agrobacterium tumifaciens nt1/ ...201526601485
biofilms produced by burkholderia cenocepacia: influence of media and solid supports on composition of matrix exopolysaccharides.bacteria usually grow forming biofilms, which are communities of cells embedded in a self-produced dynamic polymeric matrix, characterized by a complex three-dimensional structure. the matrix holds cells together and above a surface, and eventually releases them, resulting in colonization of other surfaces. although exopolysaccharides (epols) are important components of the matrix, determination of their structure is usually performed on samples produced in non-biofilm conditions, or indirectly ...201626586192
draft genome sequence of burkholderia cenocepacia strain 869t2, a plant-beneficial endophytic bacterium.an endophytic bacterium, burkholderia cenocepacia 869t2, isolated from vetiver grass, has shown its abilities for both in planta biocontrol and plant growth promotion. its draft genome sequence was determined to provide insights into those metabolic pathways involved in plant-beneficial activity. this is the first genome report for endophytic b. cenocepacia.201526564046
arnt proteins that catalyze the glycosylation of lipopolysaccharide share common features with bacterial n-oligosaccharyltransferases.arnt is a glycosyltransferase that catalyzes the addition of 4-amino-4-deoxy-l-arabinose (l-ara4n) to the lipid a moiety of the lipopolysaccharide. this is a critical modification enabling bacteria to resist killing by antimicrobial peptides. arnt is an integral inner membrane protein consisting of 13 predicted transmembrane helices and a large periplasmic c-terminal domain. we report here the identification of a functional motif with a canonical consensus sequence dexryax(5)mx(3)gxwx(9)yfekpx(4 ...201626515403
pseudomonas aeruginosa displays an altered phenotype in vitro when grown in the presence of mannitol.d-mannitol has been approved in dry powder formulation as an effective antimucolytic agent in patients with cystic fibrosis. what is not known is the effect of adding a metabolisable sugar on the biology of chronic bacterial pathogens in the cf lung. therefore, a series of simple in vitro experiments were performed to examine the effect of adding d-mannitol on the phenotype of the cf respiratory pathogens pseudomonas aeruginosa and burkholderia cenocepacia. clinical isolates (n = 86) consisting ...201526510267
assay development for image-based quantification of intracellular bacterial replication and analysis of the innate immune response to infection.severe bacterial infection can lead to inflammation, host tissue damage, and ultimately disseminated septic shock. the mammalian innate immune system responds to microbial infection through the detection of invariant pathogen-associated molecular patterns (pamps) by a range of pattern recognition receptors (prrs) expressed by the host cell. a successful immune response involves tightly coordinated signaling from these receptors, leading to a robust transcriptional response producing cytokines an ...201526505731
evidence for the widespread production of dsf family signal molecules by members of the genus burkholderia by the aid of novel biosensors.many bacteria employ cis-2-unsaturated fatty acids, referred to as dsf (diffusible signal factor) family signals, to communicate with each other. such systems have been shown to control biofilm formation, motility, production of hydrolytic enzymes and expression of virulence factors. we report the construction of novel biosensors on the basis of components of the burkholderia-dsf (bdsf) dependent circuitry of burkholderia  cenocepacia h111 and evaluated their utility for detecting the production ...201626487448
protein engineering of a nitrilase from burkholderia cenocepacia j2315 for efficient and enantioselective production of (r)-o-chloromandelic acid.the nitrilase-mediated pathway has significant advantages in the production of optically pure aromatic α-hydroxy carboxylic acids. however, low enantioselectivity and activity are observed on hydrolyzing o-chloromandelonitrile to produce optically pure (r)-o-chloromandelic acid. in the present study, a protein engineering approach was successfully used to enhance the performance of nitrilase obtained from burkholderia cenocepacia strain j2315 (bcj2315) in hydrolyzing o-chloromandelonitrile. four ...201526431972
quantification of type vi secretion system activity in macrophages infected with burkholderia cenocepacia.the gram-negative bacterial type vi secretion system (t6ss) delivers toxins to kill or inhibit the growth of susceptible bacteria, while other secretion systems target eukaryotic cells. deletion of atsr, a negative regulator of virulence factors in b. cenocepacia k56-2, increases t6ss activity. macrophages infected with a k56-2 δatsr mutant display dramatic alterations in their actin cytoskeleton architecture that rely on the t6ss, which is responsible for the inactivation of multiple rho-family ...201526364149
survival dynamics of cystic fibrosis-related gram-negative bacterial pathogens (pseudomonas aeruginosa and burkholderia cenocepacia) in dead sea and atlantic ocean waters.clinical cystic fibrosis (cf) pseudomonas aeruginosa (n=6) and burkholderia cenocepacia (n=4) were inoculated in marine brines from the dead sea and the atlantic ocean and their survival was monitored over a 1 month duration. in dead sea samples, all p. aeruginosa and b. cenocepacia isolates were non-detectable by culture following 24 h incubation, including the non-selective enrichment samples. in the atlantic ocean brine, over a 1 month period, mean p. aeruginosa counts decreased by only 0.25 ...201526322762
efflux-mediated resistance to a benzothiadiazol derivative effective against burkholderia cenocepacia.burkholderia cenocepacia is a major concern for people suffering from cystic fibrosis as it contributes to serious respiratory tract infections. the lack of drugs effective against this opportunistic pathogen, along with the high level of resistance to multiple antibiotics, render the treatment of these infections particularly difficult. here a new compound, belonging to the 2,1,3-benzothiadiazol-5-yl family (10126109), with a bactericidal effect and a minimal inhibitory concentration (mic) of 8 ...201526300878
an electron transfer flavoprotein is essential for viability and its depletion causes a rod-to-sphere change in burkholderia cenocepacia.essential gene studies often reveal novel essential functions for genes with dispensable homologues in other species. this is the case with the widespread family of electron transfer flavoproteins (etfs), which are required for the metabolism of specific substrates or for symbiotic nitrogen fixation in some bacteria. despite these non-essential functions high-throughput screens have identified etfs as putatively essential in several species. in this study, we constructed a conditional expression ...201526253539
intracellular survival of burkholderia cepacia complex in phagocytic cells.burkholderia cepacia complex (bcc) species are a group of gram-negative opportunistic pathogens that infect the airways of cystic fibrosis patients, and occasionally they infect other immunocompromised patients. bcc bacteria display high-level multidrug resistance and chronically persist in the infected host while eliciting robust inflammatory responses. studies using macrophages, neutrophils, and dendritic cells, combined with advances in the genetic manipulation of these bacteria, have increas ...201526220706
identification of synergists that potentiate the action of polymyxin b against burkholderia cenocepacia.burkholderia cenocepacia and other members of the burkholderia cepacia complex (bcc) are highly multidrug-resistant bacteria that cause severe pulmonary infections in patients with cystic fibrosis. a screen of 2686 compounds derived from marine organisms identified molecules that could synergise with polymyxin b (pmb) to inhibit the growth of b. cenocepacia. at 1 μg/ml, five compounds synergised with pmb and inhibited the growth of b. cenocepacia by ≥70% compared with growth in pmb alone. follow ...201526187366
burkholderia cenocepacia and salmonella enterica arnt proteins that transfer 4-amino-4-deoxy-l-arabinose to lipopolysaccharide share membrane topology and functional amino acids.we recently demonstrated that incorporation of 4-amino-4-deoxy-l-arabinose (l-ara4n) to the lipid a moiety of lipopolysaccharide (lps) is required for transport of lps to the outer membrane and viability of the gram-negative bacterium burkholderia cenocepacia. arnt is a membrane protein catalyzing the transfer of l-ara4n to the lps molecule at the periplasmic face of the inner membrane, but its topology and mechanism of action are not well characterized. here, we elucidate the topology of arnt a ...201526030265
incidence of burkholderia contaminans at a cystic fibrosis centre with an unusually high representation of burkholderia cepacia during 15 years of epidemiological surveillance.the burkholderia cepacia complex (bcc) is a heterogeneous group of bacteria comprising around 20 related species. these bacteria are important opportunistic pathogens, especially in cystic fibrosis (cf) patients, and are associated with a worse prognosis and decreased life expectancy. the taxonomic position of 20 bcc isolates retrieved from cf patients receiving care at hospital santa maria (hsm), in lisbon, from 1995 to 2006, was re-examined in the present work. these isolates, formerly classif ...201526002942
the rate and molecular spectrum of spontaneous mutations in the gc-rich multichromosome genome of burkholderia cenocepacia.spontaneous mutations are ultimately essential for evolutionary change and are also the root cause of many diseases. however, until recently, both biological and technical barriers have prevented detailed analyses of mutation profiles, constraining our understanding of the mutation process to a few model organisms and leaving major gaps in our understanding of the role of genome content and structure on mutation. here, we present a genome-wide view of the molecular mutation spectrum in burkholde ...201525971664
metabolic pathways of pseudomonas aeruginosa involved in competition with respiratory bacterial pathogens.chronic airway infection by pseudomonas aeruginosa considerably contributes to lung tissue destruction and impairment of pulmonary function in cystic-fibrosis (cf) patients. complex interplays between p. aeruginosa and other co-colonizing pathogens including staphylococcus aureus, burkholderia sp., and klebsiella pneumoniae may be crucial for pathogenesis and disease progression.201525954256
enhanced xylose fermentation and ethanol production by engineered saccharomyces cerevisiae strain.we have recently demonstrated that heterologous expression of a bacterial xylose isomerase gene (xyla) of burkholderia cenocepacia enabled a laboratorial saccharomyces cerevisiae strain to ferment xylose anaerobically, without xylitol accumulation. however, the recombinant yeast fermented xylose slowly. in this study, an evolutionary engineering strategy was applied to improve xylose fermentation by the xyla-expressing yeast strain, which involved sequential batch cultivation on xylose. the resu ...201525852993
lectins from opportunistic bacteria interact with acquired variable-region glycans of surface immunoglobulin in follicular lymphoma.b-cell antigen receptor (bcr) expression is a key feature of most b-cell lymphomas, but the mechanisms of bcr signal induction and the involvement of autoantigen recognition remain unclear. in follicular lymphoma (fl) b cells, bcr expression is retained despite a chromosomal translocation that links the antiapoptotic gene bcl2 to the regulatory elements of immunoglobulin genes, thereby disrupting 1 heavy-chain allele. a remarkable feature of fl-bcrs is the acquisition of potential n-glycosylatio ...201525784678
quantification of pseudomonas aeruginosa in multispecies biofilms using pma-qpcr.multispecies biofilms are an important healthcare problem and may lead to persistent infections. these infections are difficult to treat, as cells in a biofilm are highly resistant to antimicrobial agents. while increasingly being recognized as important, the properties of multispecies biofilms remain poorly studied. in order to do so, the quantification of the individual species is needed. the current cultivation-based approaches can lead to an underestimation of the actual cell number and are ...201525755923
burkholderia cenocepacia strain ceib s5-1, a rhizosphere-inhabiting bacterium with potential in bioremediation.burkholderia cenocepacia is considered an opportunistic pathogen from humans and may cause disease in plants. a bioprospection from a plaguicide-contaminated agricultural field in mexico identified several methyl parathion-degrading bacteria. here, we report the draft genome sequence of b. cenocepacia strain ceib s5-1, which gave us clues into ecological biodiversity.201525744996
investigation of the multifaceted iron acquisition strategies of burkholderia cenocepacia.burkholderia cenocepacia is a bacterial pathogen which causes severe respiratory infections in cystic fibrosis (cf). these studies were aimed at gaining an insight into the iron acquisition strategies of b. cenocepacia. in iron restricted conditions, genes associated with the synthesis and utilisation of ornibactin (pvda, orba, orb f) were significantly upregulated compared to the expression of pyochelin associated genes (pchd, fpta). in the absence of alternative iron sources, b. cenocepacia j2 ...201525725797
search for microorganisms in men with urologic chronic pelvic pain syndrome: a culture-independent analysis in the mapp research network.we used next-generation, state-of-the-art, culture independent methodology to survey urine microbiota of males with urologic chronic pelvic pain syndrome and control participants enrolled in the mapp network to investigate a possible microbial etiology.201525596358
outcomes of intraoperative extracorporeal membrane oxygenation versus cardiopulmonary bypass for lung transplantation.the study objective was to compare the outcomes of intraoperative extracorporeal membrane oxygenation versus cardiopulmonary bypass support in lung transplantation.201525583107
characterization of a novel two-component system in burkholderia cenocepacia.two-component systems are important regulatory systems that allow bacteria to adjust to environmental conditions, and in some bacteria are used in pathogenesis. we identified a novel two-component system in burkholderia cenocepacia, an opportunistic pathogen that causes pneumonia in cystic fibrosis (cf) patients. the putative operon encodes bces, a sensor kinase, and bcer, a response regulator. our studies indicated that the bcer mutant showed a statistically significant decrease in protease, sw ...201525519693
character displacement and the evolution of niche complementarity in a model biofilm community.colonization of vacant environments may catalyze adaptive diversification and be followed by competition within the nascent community. how these interactions ultimately stabilize and affect productivity are central problems in evolutionary ecology. diversity can emerge by character displacement, in which selection favors phenotypes that exploit an alternative resource and reduce competition, or by facilitation, in which organisms change the environment and enable different genotypes or species t ...201525494960
burkholderia species infections in patients with cystic fibrosis in british columbia, canada. 30 years' experience.we have been collecting burkholderia species bacteria from patients with cystic fibrosis (cf) for the last 30 years. during this time, our understanding of their multispecies taxonomy and infection control has evolved substantially.201525474359
cd4+ t cell epitopes of flic conserved between strains of burkholderia: implications for vaccines against melioidosis and cepacia complex in cystic fibrosis.burkholderia pseudomallei is the causative agent of melioidosis characterized by pneumonia and fatal septicemia and prevalent in southeast asia. related burkholderia species are strong risk factors of mortality in cystic fibrosis (cf). the b. pseudomallei flagellar protein flic is strongly seroreactive and vaccination protects challenged mice. we assessed b. pseudomallei flic peptide binding affinity to multiple hla class ii alleles and then assessed cd4 t cell immunity in hla class ii transgeni ...201425392525
retraction for ramos et al., mtvr is a global small noncoding regulatory rna in burkholderia cenocepacia.volume 195, no. 16, p. 3514–3523, 2013. a number of problems related to images published in this paper have been brought to our attention. figure 1d contains duplicated images in lanes s and le, and fig. 4d and 6b contain images previously published in articles in this journal and in microbiology and microbial pathogenesis, i.e., the following: c. g. ramos, s. a. sousa, a. m. grilo, j. r. feliciano, and j. h. leitão, j. bacteriol. 193:1515–1526, 2011. doi:10.1128/jb.01374-11. s. a. sousa, c. g. ...201425319527
retraction for ramos et al., the second rna chaperone, hfq2, is also required for survival under stress and full virulence of burkholderia cenocepacia j2315.volume 193, no. 7, p.1515–1526, 2011. problems related to images published in this paper have been brought to our attention. figure 8 contains duplicated images as well as images previously published in articles in microbiology and microbial pathogenesis, i.e., the following: s. a. sousa, c. g. ramos, l. m. moreira, and j. h. leitão, microbiology 156:896–908, 2010. http://dx.doi.org/10.1099/mic.0.035139-0. c. g. ramos, s. a. sousa, a. m. grilo, l. eberl, and j. h. leitão, microb. pathog. 48:168– ...201425319526
immunological function of familial mediterranean fever disease protein pyrin.pyrin, encoded by mefv gene, is conserved in humans and mice. mutations in the mefv gene are associated with the human autoinflammatory disease familial mediterranean fever (fmf). pyrin can interact with the inflammasome adaptor asc and induce inflammatory caspase-1 activation in monocytic cells, but the physiological function of pyrin has been unknown for many years. here we summarize previous studies of pyrin function under the context of fmf and immunity, and discuss a recent study demonstrat ...201425307949
lung transplant for a patient with cystic fibrosis and active burkholderia cenocepacia pneumonia.lung transplant for cystic fibrosis has been considered contraindicated in patients who have burkholderia cenocepacia infection. a 24-year-old white woman who had cystic fibrosis presented with respiratory failure caused by b. cenocepacia pneumonia. she was treated with broad-spectrum antibiotics and a double-lung transplant. the chest cavity and both bronchi were irrigated with 0.5% povidone-iodine solution. for immunosuppression, she received induction therapy with alemtuzumab (15 mg) and meth ...201425299375
parallel evolution of small colony variants in burkholderia cenocepacia biofilms.a common phenotype within bacterial biofilms is the small, "wrinkly" colony, which may associate with worse prognoses from biofilm-associated infections. the mechanisms that produce these variants in burkholderia are undefined. here we report the mutational and ecological causes of wrinkly (w) colonies that evolved during experimental biofilm evolution of burkholderia cenocepacia. mutations clustered in a homologous pathway to the pseudomonas wsp operon but with a distinct terminal signaling mec ...201425263109
a markerless deletion method for genetic manipulation of burkholderia cenocepacia and other multidrug-resistant gram-negative bacteria.genetic manipulation of multidrug-resistant bacteria is often difficult and hinders progress in understanding their physiology and pathogenesis. this book chapter highlights advances in genetic manipulation of burkholderia cenocepacia, which are also applicable to other members of the burkholderia cepacia complex and multidrug-resistant gram-negative bacteria of other genera. the method detailed here is based on the i-scei homing endonuclease system, which can be efficiently used for chromosomal ...201425172289
the bcesm genomic region contains a regulator involved in quorum sensing and persistence in burkholderia cenocepacia j2315.in this study, we investigated the function of bcam0257-8-9 located in the bcesm region of the burkholderia cenocepacia j2315 genome.201425156374
the attenuated virulence of a burkholderia cenocepacia paaabcde mutant is due to inhibition of quorum sensing by release of phenylacetic acid.the phenylacetic acid degradation pathway of burkholderia cenocepacia is active during cystic fibrosis-like conditions and is necessary for full pathogenicity of b. cenocepacia in nematode and rat infection models; however, the reasons for such requirements are unknown. here, we show that the attenuated virulence of a phenylacetic acid catabolism mutant is due to quorum sensing inhibition. unlike wild-type b. cenocepacia, a deletion mutant of the phenylacetyl-coa monooxygenase complex (δpaaabcde ...201425155974
protein profiling analyses of the outer membrane of burkholderia cenocepacia reveal a niche-specific proteome.outer membrane proteins (omps) are integral β-barrel proteins of the gram-negative bacterial cell wall and are crucial to bacterial survival within the macrophages and for eukaryotic cell invasion. here, we used liquid chromatography tandem mass spectrometry (lc-ms/ms) to comprehensively assess the outer membrane proteome of burkholderia cenocepacia, an opportunistic pathogen causing cystic fibrosis (cf), in conditions mimicking four major ecological niches: water, cf sputum, soil, and plant lea ...201525081413
innate immune sensing of bacterial modifications of rho gtpases by the pyrin inflammasome.cytosolic inflammasome complexes mediated by a pattern recognition receptor (prr) defend against pathogen infection by activating caspase 1. pyrin, a candidate prr, can bind to the inflammasome adaptor asc to form a caspase 1-activating complex. mutations in the pyrin-encoding gene, mefv, cause a human autoinflammatory disease known as familial mediterranean fever. despite important roles in immunity and disease, the physiological function of pyrin remains unknown. here we show that pyrin mediat ...201424919149
elucidation of the burkholderia cenocepacia hopanoid biosynthesis pathway uncovers functions for conserved proteins in hopanoid-producing bacteria.hopanoids are bacterial surrogates of eukaryotic membrane sterols and among earth's most abundant natural products. their molecular fossils remain in sediments spanning more than a billion years. however, hopanoid metabolism and function are not fully understood. burkholderia species are environmental opportunistic pathogens that produce hopanoids and also occupy diverse ecological niches. we investigated hopanoids biosynthesis in burkholderia cenocepacia by deletion mutagenesis and structural c ...201524888970
ifn-γ stimulates autophagy-mediated clearance of burkholderia cenocepacia in human cystic fibrosis macrophages.burkholderia cenocepacia is a virulent pathogen that causes significant morbidity and mortality in patients with cystic fibrosis (cf), survives intracellularly in macrophages, and uniquely causes systemic infections in cf. autophagy is a physiologic process that involves engulfing non-functional organelles and proteins and delivering them for lysosomal degradation, but also plays a role in eliminating intracellular pathogens, including b. cenocepacia. autophagy is defective in cf but can be stim ...201424798083
inhibition of co-colonizing cystic fibrosis-associated pathogens by pseudomonas aeruginosa and burkholderia multivorans.cystic fibrosis (cf) is a recessive genetic disease characterized by chronic respiratory infections and inflammation causing permanent lung damage. recurrent infections are caused by gram-negative antibiotic-resistant bacterial pathogens such as pseudomonas aeruginosa, burkholderia cepacia complex (bcc) and the emerging pathogen genus pandoraea. in this study, the interactions between co-colonizing cf pathogens were investigated. both pandoraea and bcc elicited potent pro-inflammatory responses ...201424790091
evaluation of liquid and solid culture media for the recovery and enrichment of burkholderia cenocepacia from distilled water.burkholderia cepacia complex (bcc) presence has been the cause of recalls of both sterile and non-sterile pharmaceutical products since these opportunistic pathogens have been implicated to cause infections to susceptible individuals. bcc are ubiquitous in nature, but in pharmaceutical settings the most common source is contaminated water systems. some strains of bcc, previously described as pseudomonas cepacia, were not readily detected by standard culture methods. we have explored different st ...201424756630
a burkholderia cenocepacia gene encoding a non-functional tyrosine phosphatase is required for the delayed maturation of the bacteria-containing vacuoles in macrophages.burkholderia cenocepacia infects patients with cystic fibrosis. we have previously shown that b. cenocepacia can survive in macrophages within membrane vacuoles [b. cenocepacia-containing vacuoles (bccvs)] that preclude fusion with the lysosome. the bacterial factors involved in b. cenocepacia intracellular survival are not fully elucidated. we report here that deletion of bcam0628, encoding a predicted low molecular weight protein tyrosine phosphatase (lmw-ptp) that is restricted to b. cenocepa ...201424728272
involvement of toxin-antitoxin modules in burkholderia cenocepacia biofilm persistence.biofilms are involved in the recalcitrance of infections due to the presence of persister cells. although the molecular basis of persistence is still largely unknown, toxin-antitoxin modules (ta) are thought to play a role in this process. in this study, we investigated whether ta modules contribute to persistence toward antibiotics in burkholderia cenocepacia j2315. sixteen pairs of genes were identified based on their apparent similarity to ta modules. overexpression of the putative toxins had ...201424719230
a general protein o-glycosylation system within the burkholderia cepacia complex is involved in motility and virulence.bacteria of the burkholderia cepacia complex (bcc) are pathogens of humans, plants, and animals. burkholderia cenocepacia is one of the most common bcc species infecting cystic fibrosis (cf) patients and its carriage is associated with poor prognosis. in this study, we characterized a general o-linked protein glycosylation system in b. cenocepacia k56-2. the pgllbc o-oligosaccharyltransferase (o-otase), encoded by the cloned gene bcal0960, was shown to be capable of transferring a heptasaccharid ...201424673753
regulation of biofilm formation in pseudomonas and burkholderia species.in the present review, we describe and compare the molecular mechanisms that are involved in the regulation of biofilm formation by pseudomonas putida, pseudomonas fluorescens, pseudomonas aeruginosa and burkholderia cenocepacia. our current knowledge suggests that biofilm formation is regulated by cyclic diguanosine-5'-monophosphate (c-di-gmp), small rnas (srna) and quorum sensing (qs) in all these bacterial species. the systems that employ c-di-gmp as a second messenger regulate the production ...201424592823
high-resolution structure of the m14-type cytosolic carboxypeptidase from burkholderia cenocepacia refined exploiting pdb_redo strategies.a potential cytosolic metallocarboxypeptidase from burkholderia cenocepacia has been crystallized and a synchrotron-radiation microfocus beamline allowed the acquisition of diffraction data to 1.9 å resolution. the asymmetric unit comprises a tetramer containing over 1500 amino acids, and the high-throughput automated protocols embedded in pdb_redo were coupled with model-map inspections in refinement. this approach has highlighted the value of such protocols for efficient analyses. the subunit ...201424531462
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