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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
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
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
burkholderia cenocepacia infection: disruption of phagocyte immune functions through rho gtpase inactivation.phagocytosis is an important component of innate immunity that contributes to the eradication of infectious microorganisms; however, successful bacterial pathogens often evade different aspects of host immune responses. a common bacterial evasion strategy entails the production of toxins and/or effectors that disrupt normal host cell processes and because of their importance rho-family gtpases are often targeted. burkholderia cenocepacia, an opportunistic pathogen that has a propensity to infect ...201522622109
burkholderia cepacia complex phage-antibiotic synergy (pas): antibiotics stimulate lytic phage activity.the burkholderia cepacia complex (bcc) is a group of at least 18 species of gram-negative opportunistic pathogens that can cause chronic lung infection in cystic fibrosis (cf) patients. bcc organisms possess high levels of innate antimicrobial resistance, and alternative therapeutic strategies are urgently needed. one proposed alternative treatment is phage therapy, the therapeutic application of bacterial viruses (or bacteriophages). recently, some phages have been observed to form larger plaqu ...201525452284
the use of doripenem in pediatric cystic fibrosis patients in case of meropenem shortages.ceftazidime is the only anti-pseudomonal beta-lactam that has been reported to be administered by extended infusion in pediatric cystic fibrosis (cf) patients. a small pediatric pharmacokinetic/pharmacodynamic study has been published regarding the use of intermittent extended infusion doripenem in the treatment of an acute pulmonary exacerbation (ape) in pediatric cf patients; however, clinical use of intermittent extended infusion doripenem in pediatric cf patients has not been previously repo ...201423661625
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
contamination of hypertonic saline solutions in use by cystic fibrosis patients in israel.treatment of cystic fibrosis (cf) patients with inhaled hypertonic saline (hs) solutions is safe, beneficial and reduces exacerbation rates. we studied contamination of solutions used by israeli cf patients for prolonged periods.201424484849
burkholderia dolosa phenotypic variation during the decline in lung function of a cystic fibrosis patient during 5.5 years of chronic colonization.although rarely isolated from cystic fibrosis (cf) patients, burkholderia dolosa is associated with accelerated lung function decline. during 18 years of epidemiological surveillance in the major portuguese cf centre in lisbon, only one patient was infected with b. dolosa. pulmonary deterioration, associated with the evolution of forced expiratory volume in 1 s, occurred during 5.5 years of colonization with this b. dolosa clone (with the new sequence type st-668). transient co-colonization with ...201424469681
antimicrobial properties of an oxidizer produced by burkholderia cenocepacia p525.a compound with both oxidizing properties and antibiotic properties was extracted and purified from broth cultures of burkholderia cenocepacia strain p525. a four step purification procedure was used to increase its specific activity ~400-fold and to yield a hplc-uv chromatogram containing a single major peak. size exclusion chromatography suggests a molecular mass of ~1,150 and uv spectroscopy suggests the presence of a polyene structure consisting of as many as six conjugated double bonds. bio ...201424384626
optimization of resazurin-based viability staining for quantification of microbial biofilms.the resazurin-based viability staining is often used to quantify viable biofilm cells grown in microtiter plates (mtp). the non-fluorescent resazurin is reduced by metabolically active cells to resorufin which is fluorescent. the amount of fluorescence generated is related to the number of viable cells present. unfortunately, the linear range of the method is restricted and the lower limit of quantification is approximately 10(6) colony forming units (cfu) per biofilm. the goal of the present st ...201424365109
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
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
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
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
kinetic characterization of an oxidative, cooperative hmg-coa reductase from burkholderia cenocepacia.3-hydroxy-3-methylglutaryl coenzyme a reductase (hmgr) is a key enzyme in endogenous cholesterol biosynthesis in mammals and isoprenoid biosynthesis via the mevalonate pathway in other eukaryotes, archaea and some eubacteria. in most organisms that express this enzyme, it catalyzes the nad(p)h-dependent reduction of hmg-coa to mevalonate. we have cloned and characterized the 6x-his-tagged hmgr from the opportunistic lung pathogen burkholderia cenocepacia. kinetic characterization shows that the ...201424316250
analysis of genomic characters reveals that four distinct gene clusters are correlated with different functions in burkholderia cenocepacia au 1054.possessing three circular chromosomes is a distinct genomic characteristic of burkholderia cenocepacia au 1054, a clinically important pathogen in cystic fibrosis. in this study, base composition, codon usage and functional role category were analyzed in the b. cenocepacia au 1054 genome. although no bias in the base and codon usage was detected between any two chromosomes, function differences did exist in the genes of each chromosome. similar base composition and differential functional role c ...201424305740
pore-forming pyocin s5 utilizes the fpta ferripyochelin receptor to kill pseudomonas aeruginosa.pyocins are toxic proteins produced by some strains of pseudomonas aeruginosa that are lethal for related strains of the same species. some soluble pyocins (s2, s3 and s4) were previously shown to use the pyoverdine siderophore receptors to enter the cell. the p. aeruginosa pao1 pore-forming pyocin s5 encoding gene (pao985) was cloned into the expression vector pet15b, and the affinity-purified protein product tested for its killing activity against different p. aeruginosa strains. the results, ...201424217175
deciphering the role of burkholderia cenocepacia membrane proteins in antimicrobial properties of chitosan.chitosan, a versatile derivative of chitin, is widely used as an antimicrobial agent either alone or mixed with other natural polymers. burkholderia cenocepacia is a multidrug-resistant bacteria and difficult to eradicate. our previous studies shown that chitosan had strong antibacterial activity against b. cenocepacia. in the current study, we have investigated the molecular aspects for the susceptibility of b. cenocepacia in response to chitosan antibacterial activity. we have conducted rna ex ...201424213809
oxidative stress in cystic fibrosis patients with burkholderia cenocepacia airway colonization: relation of 8-isoprostane concentration in exhaled breath condensate to lung function decline.the association between oxidative stress and neutrophilic inflammation in cystic fibrosis (cf) lung disease is well recognized. 8-isoprostane is a product of non-enzymatic oxidation of arachidonic acid. the aim of the present study was to examine the relationship between lung function decline and 8-isoprostane concentrations in exhaled breath condensate (ebc) in cf patients with burkholderia cenocepacia airway colonization. concentrations of 8-isoprostane in ebc were measured in 24 stable cf pat ...201424132725
investigating the role of matrix components in protection of burkholderia cepacia complex biofilms against tobramycin.burkholderia cepacia complex (bcc) organisms produce a wide variety of potential virulence factors, including exopolysaccharides (eps), and exhibit intrinsic resistance towards many antibiotics. in the present study we investigated the contribution of bcc biofilm matrix components, including extracellular dna, cepacian and poly-β-1,6-n-acetylglucosamine, to tobramycin susceptibility.201423932109
respiratory infections in patients with cystic fibrosis undergoing lung transplantation.cystic fibrosis is an inherited disease characterised by chronic respiratory infections associated with bronchiectasis. lung transplantation has helped to extend the lives of patients with cystic fibrosis who have advanced lung disease. however, persistent, recurrent, and newly acquired infections can be problematic. classic cystic fibrosis-associated organisms, such as staphylococcus aureus and pseudomonas aeruginosa, are generally manageable post-transplantation, and are associated with favour ...201424461904
bacteria that inhibit quorum sensing decrease biofilm formation and virulence in pseudomonas aeruginosa pao1.in this study, we investigated the biotherapeutic potential of previously isolated quorum quenching (qq) bacteria. some of them produce and secrete small compounds that inhibit quorum sensing (qs), others quench qs by enzymatic degradation of n-acylhomoserine lactones (ahls). the supernatant of cultures of these isolates was tested for inhibitory properties against p. aeruginosa pao1 biofilms. most isolates had a moderate effect on biofilm formation, as shown by viability staining and/or stainin ...201424415453
mechanism of resistance to an antitubercular 2-thiopyridine derivative that is also active against burkholderia cenocepacia.the discovery of new compounds that are able to inhibit the growth of burkholderia cenocepacia is of primary importance for cystic fibrosis patients. here, the mechanism of resistance to a new pyridine derivative already shown to be effective against mycobacterium tuberculosis and to have good activity toward b. cenocepacia was investigated. increased expression of a resistance-nodulation-cell division (rnd) efflux system was detected in the resistant mutants, thus confirming their important rol ...201424395233
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 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
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
single amino acid substitution in homogentisate 1,2-dioxygenase is responsible for pigmentation in a subset of burkholderia cepacia complex isolates.the burkholderia cepacia complex (bcc) is a group of gram-negative bacilli that are ubiquitous in the environment and have emerged over the past 30 years as opportunistic pathogens in immunocompromised populations, specifically individuals with cystic fibrosis (cf) and chronic granulomatous disease. this complex of at least 18 distinct species is phenotypically and genetically diverse. one phenotype observed in a subset of burkholderia cenocepacia (a prominent bcc pathogen) isolates is the abili ...201425294803
differential roles of rnd efflux pumps in antimicrobial drug resistance of sessile and planktonic burkholderia cenocepacia cells.burkholderia cenocepacia is notorious for causing respiratory tract infections in people with cystic fibrosis. infections with this organism are particularly difficult to treat due to its high level of intrinsic resistance to most antibiotics. multidrug resistance in b. cenocepacia can be ascribed to different mechanisms, including the activity of efflux pumps and biofilm formation. in the present study, the effects of deletion of the 16 operons encoding resistance-nodulation-cell division (rnd) ...201425267676
development of a multiple-locus variable-number tandem-repeat typing scheme for genetic fingerprinting of burkholderia cenocepacia and application to nationwide epidemiological analysis.organisms of the burkholderia cepacia complex are especially important pathogens in cystic fibrosis (cf), with a propensity for patient-to-patient spread and long-term respiratory colonization. b. cenocepacia and burkholderia multivorans account for the majority of infections in cf, and major epidemic clones have been recognized throughout the world. the aim of the present study was to develop and evaluate a multilocus variable-number tandem-repeat (vntr) analysis (mlva) scheme for b. cenocepaci ...201425411181
regulation of hfq mrna and protein levels in escherichia coli and pseudomonas aeruginosa by the burkholderia cenocepacia mtvr srna.small non-coding rnas (srnas) are important players of gene expression regulation in bacterial pathogens. mtvr is a 136-nucleotide long srna previously identified in the human pathogen burkholderia cenocepacia j2315 and with homologues restricted to bacteria of the burkholderia cepacia complex. in this work we have investigated the effects of expressing mtvr in escherichia coli and pseudomonas aeruginosa. results are presented showing that mtvr negatively regulates the hfq mrna levels in both ba ...201424901988
comparative metabolic systems analysis of pathogenic burkholderia.burkholderia cenocepacia and burkholderia multivorans are opportunistic drug-resistant pathogens that account for the majority of burkholderia cepacia complex infections in cystic fibrosis patients and also infect other immunocompromised individuals. while they share similar genetic compositions, b. cenocepacia and b. multivorans exhibit important differences in pathogenesis. we have developed reconciled genome-scale metabolic network reconstructions of b. cenocepacia j2315 and b. multivorans at ...201424163337
crystal structures of ispf from plasmodium falciparum and burkholderia cenocepacia: comparisons inform antimicrobial drug target assessment.2c-methyl-d-erythritol-2,4-cyclodiphosphate synthase (ispf) catalyzes the conversion of 4-diphosphocytidyl-2c-methyl-d-erythritol-2-phosphate to 2c-methyl-d-erythritol-2,4-cyclodiphosphate and cytidine monophosphate in production of isoprenoid-precursors via the methylerythritol phosphate biosynthetic pathway. ispf is found in the protozoan plasmodium falciparum, a parasite that causes cerebral malaria, as well as in many gram-negative bacteria such as burkholderia cenocepacia. ispf represents a ...201424410837
localization of burkholderia cepacia complex bacteria in cystic fibrosis lungs and interactions with pseudomonas aeruginosa in hypoxic mucus.the localization of burkholderia cepacia complex (bcc) bacteria in cystic fibrosis (cf) lungs, alone or during coinfection with pseudomonas aeruginosa, is poorly understood. we performed immunohistochemistry for bcc and p. aeruginosa bacteria on 21 coinfected or singly infected cf lungs obtained at transplantation or autopsy. parallel in vitro experiments examined the growth of two bcc species, burkholderia cenocepacia and burkholderia multivorans, in environments similar to those occupied by p. ...201425156735
rsam: a transcriptional regulator of burkholderia spp. with novel fold.burkholderia cepacia complex is a set of closely related bacterial species that are notorious pathogens of cystic fibrosis patients, responsible for life-threatening lung infections. expression of several virulence factors of burkholderia cepacia complex is controlled by a mechanism known as quorum sensing (qs). qs is a means of bacterial communication used to coordinate gene expression in a cell-density-dependent manner. the system involves the production of diffusible signaling molecules (n-ac ...201424916958
putrescine reduces antibiotic-induced oxidative stress as a mechanism of modulation of antibiotic resistance in burkholderia cenocepacia.communication of antibiotic resistance among bacteria via small molecules is implicated in transient reduction of bacterial susceptibility to antibiotics, which could lead to therapeutic failures aggravating the problem of antibiotic resistance. released putrescine from the extremely antibiotic-resistant bacterium burkholderia cenocepacia protects less-resistant cells from different species against the antimicrobial peptide polymyxin b (pmb). exposure of b. cenocepacia to sublethal concentration ...201424820075
characterization of bcam0224, a multifunctional trimeric autotransporter from the human pathogen burkholderia cenocepacia.members of the trimeric autotransporter adhesin (taa) family play a crucial role in adhesion of gram-negative pathogens to host cells. moreover, these proteins are multifunctional virulence factors involved in several other biological traits, including invasion into host cells and evasion of the host immune system. in cystic fibrosis epidemic burkholderia cenocepacia strain j2315, we identified a unique taa (bcam0224)-encoding gene, previously described as being implicated in virulence. here, we ...201424659767
genome sequence of burkholderia cenocepacia h111, a cystic fibrosis airway isolate.the burkholderia cepacia complex (bcc) is a group of related bacterial species that are commonly isolated from environmental samples. members of the bcc can cause respiratory infections in cystic fibrosis patients and immunocompromised individuals. we report here the genome sequence of burkholderia cenocepacia h111, a well-studied model strain of the bcc.201424723723
the iclr-family regulator bapr controls biofilm formation in b. cenocepacia h111.in burkholderia cenocepacia h111, the large surface protein bapa plays a crucial role in the formation of highly structured communities, known as biofilms. we have recently demonstrated that quorum sensing (qs) is necessary for the maximal expression of bapa. in this study we identify bapr, a protein from the iclr family of transcriptional regulators that, in conjunction with qs, controls biofilm formation by affecting the expression of bapa. we present evidence that, in addition to bapa, bapr i ...201424658785
reducing virulence of the human pathogen burkholderia by altering the substrate specificity of the quorum-quenching acylase pvdq.the use of enzymes to interfere with quorum sensing represents an attractive strategy to fight bacterial infections. we used pvdq, an effective quorum-quenching enzyme from pseudomonas aeruginosa, as a template to generate an acylase able to effectively hydrolyze c8-hsl, the major communication molecule produced by the burkholderia species. we discovered that the combination of two single mutations leading to variant pvdq(lα146w,fβ24y) conferred high activity toward c8-hsl. exogenous addition of ...201424474783
identification of the flagellin glycosylation system in burkholderia cenocepacia and the contribution of glycosylated flagellin to evasion of human innate immune responses.burkholderia cenocepacia is an opportunistic pathogen threatening patients with cystic fibrosis. flagella are required for biofilm formation, as well as adhesion to and invasion of epithelial cells. recognition of flagellin via the toll-like receptor 5 (tlr5) contributes to exacerbate b. cenocepacia-induced lung epithelial inflammatory responses. in this study, we report that b. cenocepacia flagellin is glycosylated on at least 10 different sites with a single sugar, 4,6-dideoxy-4-(3-hydroxybuta ...201424841205
antibacterial activity of a lectin-like burkholderia cenocepacia protein.bacteriocins of the llpa family have previously been characterized in the γ-proteobacteria pseudomonas and xanthomonas. these proteins are composed of two mmbl (monocot mannose-binding lectin) domains, a module predominantly and abundantly found in lectins from monocot plants. genes encoding four different types of llpa-like proteins were identified in genomes from strains belonging to the burkholderia cepacia complex (bcc) and the burkholderia pseudomallei group. a selected recombinant llpa-lik ...201323737242
the unexpected discovery of a novel low-oxygen-activated locus for the anoxic persistence of burkholderia cenocepacia.burkholderia cenocepacia is a gram-negative aerobic bacterium that belongs to a group of opportunistic pathogens displaying diverse environmental and pathogenic lifestyles. b. cenocepacia is known for its ability to cause lung infections in people with cystic fibrosis and it possesses a large 8 mb multireplicon genome encoding a wide array of pathogenicity and fitness genes. transcriptomic profiling across nine growth conditions was performed to identify the global gene expression changes made w ...201323486248
biofilm-grown burkholderia cepacia complex cells survive antibiotic treatment by avoiding production of reactive oxygen species.the presence of persister cells has been proposed as a factor in biofilm resilience. in the present study we investigated whether persister cells are present in burkholderia cepacia complex (bcc) biofilms, what the molecular basis of antimicrobial tolerance in bcc persisters is, and how persisters can be eradicated from bcc biofilms. after treatment of bcc biofilms with high concentrations of various antibiotics often a small subpopulation survived. to investigate the molecular mechanism of tole ...201323516582
isolation and characterization of burkholderia rinojensis sp. nov., a non-burkholderia cepacia complex soil bacterium with insecticidal and miticidal activities.isolate a396, a bacterium isolated from a japanese soil sample demonstrated strong insecticidal and miticidal activities in laboratory bioassays. the isolate was characterized through biochemical methods, fatty acid methyl ester (fame) analysis, sequencing of 16s rrna, multilocus sequence typing and analysis, and dna-dna hybridization. fame analysis matched a396 to burkholderia cenocepacia, but this result was not confirmed by 16s rrna or dna-dna hybridization. 16s rrna sequencing indicated clos ...201324096416
phenotypic and genotypic characterisation of burkholderia cenocepacia j2315 mutants affected in homoserine lactone and diffusible signal factor-based quorum sensing systems suggests interplay between both types of systems.many putative virulence factors of burkholderia cenocepacia are controlled by various quorum sensing (qs) circuits. these qs systems either use n-acyl homoserine lactones (ahl) or cis-2-dodecenoic acid ("burkholderia diffusible signal factor", bdsf) as signalling molecules. previous work suggested that there is little cross-talk between both types of systems. we constructed mutants in b. cenocepacia strain j2315, in which genes encoding cepi (bcam1870), ccii (bcam0239a) and the bdsf synthase (bc ...201323383071
genetic diversity of burkholderia contaminans isolates from cystic fibrosis patients in argentina.a total of 120 burkholderia cepacia complex isolates collected during 2004-2010 from 66 patients in two cystic fibrosis reference centers in argentina were analyzed. burkholderia contaminans was the species most frequently recovered (57.6%), followed by burkholderia cenocepacia (15%), a species distribution not reported so far. the reca-pcr-based techniques applied to the b. contaminans isolates revealed that 85% of the population carried the reca-st-71 allele. our results showed the utility of ...201323135937
immunoproteomic analysis of proteins expressed by two related pathogens, burkholderia multivorans and burkholderia cenocepacia, during human infection.burkholderia cepacia complex (bcc) is an opportunistic bacterial pathogen that causes chronic infections in people with cystic fibrosis (cf). it is a highly antibiotic resistant organism and bcc infections are rarely cleared from patients, once they are colonized. the two most clinically relevant species within bcc are burkholderia cenocepacia and burkholderia multivorans. the virulence of these pathogens has not been fully elucidated and the virulence proteins expressed during human infection h ...201324260482
cis-2-dodecenoic acid signal modulates virulence of pseudomonas aeruginosa through interference with quorum sensing systems and t3ss.cis-2-dodecenoic acid (bdsf) is well known for its important functions in intraspecies signaling in burkholderia cenocepacia. previous work has also established an important role of bdsf in interspecies and inter-kingdom communications. it was identified that bdsf modulates virulence of pseudomonas aeruginosa. however, how bdsf interferes with virulence of p. aeruginosa is still not clear.201324134835
structural stability of burkholderia cenocepacia biofilms is reliant on edna structure and presence of a bacterial nucleic acid binding protein.cystic fibrosis (cf) is the most common lethal inherited genetic disorder affection caucasians. even with medical advances, cf is life-shortening with patients typically surviving only to age 38. infection of the cf lung by burkholderia cenocepacia presents exceptional challenges to medical management of these patients as clinically this microbe is resistant to virtually all antibiotics, is highly transmissible and infection of cf patients with this microbe renders them ineligible for lung trans ...201323799151
snapbcen: a novel and practical tool for genotyping burkholderia cenocepacia.burkholderia cenocepacia is the most prevalent and feared member of the burkholderia cepacia complex in lung infections of cystic fibrosis (cf). genotyping and monitoring of long-term colonization are critical at clinical units; however, the differentiation of specific lineages performed by multilocus sequence typing (mlst) is still limited to a small number of isolates due to the high cost and time-consuming procedure. the aim of this study was to optimize a protocol (the snapbcen assay) for ex ...201323761147
cis-2-dodecenoic acid quorum sensing system modulates n-acyl homoserine lactone production through rpfr and cyclic di-gmp turnover in burkholderia cenocepacia.burkholderia cenocepacia employs both n-acyl homoserine lactone (ahl) and cis-2-dodecenoic acid (bdsf) quorum sensing (qs) systems in regulation of bacterial virulence. it was shown recently that disruption of bdsf synthase rpffbc caused a reduction of ahl signal production in b. cenocepacia. however, how bdsf system influences ahl system is still not clear.201323815566
proteomic profiling of burkholderia cenocepacia clonal isolates with different virulence potential retrieved from a cystic fibrosis patient during chronic lung infection.respiratory infections with burkholderia cepacia complex (bcc) bacteria in cystic fibrosis (cf) are associated with a worse prognosis and increased risk of death. in this work, we assessed the virulence potential of three b. cenocepacia clonal isolates obtained from a cf patient between the onset of infection (isolate ist439) and before death with cepacia syndrome 3.5 years later (isolate ist4113 followed by ist4134), based on their ability to invade epithelial cells and compromise epithelial mo ...201324349432
draft genome sequences of burkholderia cenocepacia et12 lineage strains k56-2 and bc7.the burkholderia cepacia complex (bcc) is a group of closely related bacteria that are responsible for respiratory infections in immunocompromised humans, most notably those with cystic fibrosis (cf). we report the genome sequences for burkholderia cenocepacia et12 lineage cf isolates k56-2 and bc7.201324136849
identification and characterization of ϕh111-1: a novel myovirus with broad activity against clinical isolates of burkholderia cenocepacia.characterization of prophages in sequenced bacterial genomes is important for virulence assessment, evolutionary analysis, and phage application development. the objective of this study was to identify complete, inducible prophages in the cystic fibrosis (cf) clinical isolate burkholderia cenocepacia h111. using the prophage-finding program phage search tool (phast), we identified three putative intact prophages in the h111 sequence. virions were readily isolated from h111 culture supernatants f ...201324265978
mtvr is a global small noncoding regulatory rna in burkholderia cenocepacia.burkholderia cenocepacia j2315 is a highly epidemic and transmissible clinical isolate of the burkholderia cepacia complex (bcc), a group of bacteria causing life-threatening respiratory infections among cystic fibrosis patients. this work describes the functional analysis of the 136-nucleotide (nt)-long mtvr small noncoding rna (srna) from the bcc member b. cenocepacia j2315, with homologues restricted to the genus burkholderia. bioinformatic target predictions revealed a total of 309 mrnas to ...201323729649
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
biochemical and functional studies on the burkholderia cepacia complex bcen gene, encoding a gdp-d-mannose 4,6-dehydratase.this work reports the biochemical and functional analysis of the burkholderia cenocepacia j2315 bcen gene, encoding a protein with gdp-d-mannose 4,6-dehydratase enzyme activity (e.c.4.2.1.47). data presented indicate that the protein is active when in the tetrameric form, catalyzing the conversion of gdp-d-mannose into gdp-4-keto-6-deoxy-d-mannose. this sugar nucleotide is the intermediary necessary for the biosynthesis of gdp-d-rhamnose, one of the sugar residues of cepacian, the major exopolys ...201323460819
burkholderia cenocepacia conditional growth mutant library created by random promoter replacement of essential genes.identification of essential genes by construction of conditional knockouts with inducible promoters allows the identification of essential genes and creation of conditional growth (cg) mutants that are then available as genetic tools for further studies. we used large-scale transposon delivery of the rhamnose-inducible promoter, prhab followed by robotic screening of rhamnose-dependent growth to construct a genomic library of 106 burkholderia cenocepacia cg mutants. transposon insertions were fo ...201323389959
discovery and characterization of a highly efficient enantioselective mandelonitrile hydrolase from burkholderia cenocepacia j2315 by phylogeny-based enzymatic substrate specificity prediction.a nitrilase-mediated pathway has significant advantages in the production of optically pure (r)-(-)-mandelic acid. however, unwanted byproduct, low enantioselectivity, and specific activity reduce its value in practical applications. an ideal nitrilase that can efficiently hydrolyze mandelonitrile to optically pure (r)-(-)-mandelic acid without the unwanted byproduct is needed.201323414071
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
bdsf inhibits candida albicans adherence to urinary catheters.cis-2-dodecenoic acid (bdsf) is a quorum-sensing signal molecule produced by the opportunistic pathogen burkholderia cenocepacia and suppresses germ tube formation of candida albicans. an in vitro model for biofilm formation evaluated the influence of bdsf on c. albicans. biofilm morphology was observed using scanning electron microscopy, cell adherence was determined using polystyrene plates and siliconized urinary catheters, and the levels of expression of genes involved in adhesion were deter ...201323948468
the in vivo extracellular life of facultative intracellular bacterial parasites: role in pathogenesis.classically labeled facultative intracellular pathogens are characterized by the ability to have an intracellular phase in the host, which is required for pathogenicity, while capable of extracellular growth in vitro. the ability of these bacteria to replicate in cell-free conditions is usually assessed by culture in artificial bacteriological media. however, the extracellular growth ability of these pathogens may also be expressed by a phase of extracellular infection in the natural setting of ...201322795971
burkholderia multivorans survival and trafficking within macrophages.cystic fibrosis (cf) patients are at great risk of opportunistic lung infection, particularly by members of the burkholderia cepacia complex (bcc). this group of bacteria can cause damage to the lung tissue of infected patients and are difficult to eradicate due to their high levels of antibiotic resistance. although the highly virulent burkholderia cenocepacia has been the focus of virulence research for the past decade, burkholderia multivorans is emerging as the most prevalent bcc species inf ...201323105020
an outbreak of burkholderia cenocepacia associated with contaminated chlorhexidine solutions prepared in the hospital.from october to december 2007, an outbreak of burkholderia cenocepacia occurred in a secondary care hospital. the 19 b cenocepacia isolated from the patients, the chlorhexidine solutions of each different ward, and the purified water that diluted these solutions exhibited an identical pulsed-field gel electrophoresis pattern. inadequate preparation of chlorhexidine solutions diluted with contaminated purified water may have resulted in an outbreak of b cenocepacia. adequate preparation of chlorh ...201323608047
podocalyxin is a glycoprotein ligand of the human pluripotent stem cell-specific probe rbc2lcn.in comprehensive glycome analysis with a high-density lectin microarray, we have previously shown that the recombinant n-terminal domain of the lectin bc2l-c from burkholderia cenocepacia (rbc2lcn) binds exclusively to undifferentiated human induced pluripotent stem (ips) cells and embryonic stem (es) cells but not to differentiated somatic cells. here we demonstrate that podocalyxin, a heavily glycosylated type 1 transmembrane protein, is a glycoprotein ligand of rbc2lcn on human ips cells and ...201323526252
novel diagnostic pcr assay for burkholderia cenocepacia epidemic strain st32 and its utility in monitoring infection in cystic fibrosis patients.a highly transmissible burkholderia cenocepacia sequence type (st) 32 strain caused a major outbreak at the prague cystic fibrosis (cf) centre in the late 1990s and early 2000s. because a large number of cf patients were affected by st32, a rapid and easy-to-use diagnostic tool for st32 infection was urgently needed for the detection of new cases as well as for long-term surveillance. the present study sought to identify unique dna sequences within the st32 genome to develop an st32 strain-speci ...201323317764
role of burkholderia cenocepacia afce and afcf genes in determining lipid-metabolism-associated phenotypes.burkholderia cenocepacia is an opportunistic pathogen that primarily infects cystic fibrosis patients. previously we have reported that mutations in shvr, a lysr-type transcriptional regulator, and shvr-regulated genes bcas0208 and bcas0201 (designated afce and afcf, respectively) affect colony morphotype, biofilm and pellicle formation and virulence in b. cenocepacia. in this study we investigated the role of afce and afcf in influencing lipid-metabolism-associated phenotypes. as previously rep ...201323306671
genetic similarity of burkholderia cenocepacia from cystic fibrosis patients.burkholderia cenocepacia may cause serious infections in patients with cystic fibrosis, and this microorganism can be highly transmissible. pulsed-field gel electrophoresis is widely used to study the dynamics of strain spread in cystic fibrosis patients. the aim of this work was to perform pulsed-field gel electrophoresis-based molecular typing of b. cenocepacia isolates to evaluate the epidemiology of this species at our hospital. a total of 28 isolates from 23 cystic fibrosis patients were an ...201323287542
analysis of human bronchial epithelial cell proinflammatory response to burkholderia cenocepacia infection: inability to secrete il-1β.burkholderia cenocepacia, the causative agent of cepacia syndrome, primarily affects cystic fibrosis patients, often leading to death. in the lung, epithelial cells serve as the initial barrier to airway infections, yet their responses to b. cenocepacia have not been fully investigated. here, we examined the molecular responses of human airway epithelial cells to b. cenocepacia infection. infection led to early signaling events such as activation of erk, akt, and nf-κb. further, tnfα, il-6, il-8 ...201323269671
functional expression of burkholderia cenocepacia xylose isomerase in yeast increases ethanol production from a glucose-xylose blend.this study presents results regarding the successful cloning of the bacterial xylose isomerase gene (xyla) of burkholderia cenocepacia and its functional expression in saccharomyces cerevisiae. the recombinant yeast showed to be competent to efficiently produce ethanol from both glucose and xylose, which are the main sugars in lignocellulosic hydrolysates. the heterologous expression of the gene xyla enabled a laboratorial yeast strain to ferment xylose anaerobically, improving ethanol productio ...201323186665
depletion of the ubiquitin-binding adaptor molecule sqstm1/p62 from macrophages harboring cftr δf508 mutation improves the delivery of burkholderia cenocepacia to the autophagic machinery.cystic fibrosis is the most common inherited lethal disease in caucasians. it is caused by mutations in the cystic fibrosis transmembrane conductance regulator (cftr), of which the cftr δf508 mutation is the most common. δf508 macrophages are intrinsically defective in autophagy because of the sequestration of essential autophagy molecules within unprocessed cftr aggregates. defective autophagy allows burkholderia cenocepacia (b. cepacia) to survive and replicate in δf508 macrophages. infection ...201323148214
experimental identification of small non-coding regulatory rnas in the opportunistic human pathogen burkholderia cenocepacia j2315.small non-coding regulatory rnas (srnas) play important roles in regulating gene expression at the post-transcriptional level and often require the rna chaperone hfq. the human opportunistic pathogen burkholderia cenocepacia j2315 encodes two distinct rna chaperones, hfq and hfq2. the present work describes the experimental identification and validation of 24 srnas from b. cenocepacia j2315, based on the co-purification of srnas with the bacterium hfq protein, followed by conversion into cdna, c ...201323142676
the burkholderia cenocepacia sensor kinase hybrid atsr is a global regulator modulating quorum-sensing signalling.burkholderia cenocepacia is commonly found in the environment and also as an important opportunistic pathogen infecting patients with cystic fibrosis. successful infection by this bacterium requires coordinated expression of virulence factors, which is achieved through different quorum sensing (qs) regulatory systems. biofilm formation and type 6 secretion system (t6ss) expression in b. cenocepacia k56-2 are positively regulated by qs and negatively regulated by the sensor kinase hybrid atsr. th ...201322830644
efficacy of the biocide steri-7 against the common gram-negative bacterial pathogens (burkholderia cenocepacia, burkholderia gladioli, burkholderia multivorans, pseudomonas aeruginosa and stenotrophomonas maltophilia) associated with cystic fibrosis (cf). 201323888610
chemical communication of antibiotic resistance by a highly resistant subpopulation of bacterial cells.the overall antibiotic resistance of a bacterial population results from the combination of a wide range of susceptibilities displayed by subsets of bacterial cells. bacterial heteroresistance to antibiotics has been documented for several opportunistic gram-negative bacteria, but the mechanism of heteroresistance is unclear. we use burkholderia cenocepacia as a model opportunistic bacterium to investigate the implications of heterogeneity in the response to the antimicrobial peptide polymyxin b ...201323844246
single-molecule atomic force microscopy unravels the binding mechanism of a burkholderia cenocepacia trimeric autotransporter adhesin.trimeric autotransporter adhesins (taas) are bacterial surface proteins that fulfil important functions in pathogenic gram-negative bacteria. prominent examples of taas are found in burkholderia cepacia complex, a group of bacterial species causing severe infections in patients with cystic fibrosis. while there is strong evidence that burkholderia cenocepacia taas mediate adhesion, aggregation and colonization of the respiratory epithelium, we still know very little about the molecular mechanism ...201323796134
fluorescent labeling agents for quorum-sensing receptors (flaqs) in live cells.lighten up: a selective fluorescent-labeling agent for quorum sensing (flaqs) can be used for the visualization of the communication pathway of bacteria in live cells (see figure). this represents a new, operationally simple, fast, and inexpensive tool for the imaging of quorum-sensing receptors by using fluorescently labeled signaling-molecule analogues.201323765553
influence of ligand presentation density on the molecular recognition of mannose-functionalised glyconanoparticles by bacterial lectin bc2l-a.polyvalent carbohydrate-protein interactions play a key role in bio- and pathological processes, including cell-cell communication and pathogen invasion. in order to study, control and manipulate these interactions gold nanoparticles have been employed as a 3d scaffold, presenting carbohydrate ligands in a multivalent fashion for use as high affinity binding partners and a model system for oligosaccharide presentation at biomacromolecular surfaces. in this study, the binding of a series of manno ...201323666402
efficient production of (r)-(-)-mandelic acid in biphasic system by immobilized recombinant e. coli.the recombinant escherichia coli m15/bcj2315 which harbored a mandelonitrilase from burkholderia cenocepacia j2315 was immobilized via catecholic chitosan and functionalized with magnetism by iron oxide nanoparticles. the immobilized cells showed high activity recovery, enhanced stability and good operability in the enantioselective hydrolysis of mandelonitrile to (r)-(-)-mandelic acid. furthermore, the immobilized cells were reused up to 15 cycles without any activity loss in completely hydroly ...201323906842
identification of burkholderia cenocepacia strain h111 virulence factors using nonmammalian infection hosts.burkholderia cenocepacia h111, a strain isolated from a cystic fibrosis patient, has been shown to effectively kill the nematode caenorhabditis elegans. we used the c. elegans model of infection to screen a mini-tn5 mutant library of b. cenocepacia h111 for attenuated virulence. of the approximately 5,500 b. cenocepacia h111 random mini-tn5 insertion mutants that were screened, 22 showed attenuated virulence in c. elegans. except for the quorum-sensing regulator cepr, none of the mutated genes c ...201323090963
burkholderia cenocepacia j2315 escapes to the cytosol and actively subverts autophagy in human macrophages.selective autophagy functions to specifically degrade cellular cargo tagged by ubiquitination, including bacteria. strains of the burkholderia cepacia complex (bcc) are opportunistic pathogens that cause life-threatening infections in patients with cystic fibrosis (cf) and chronic granulomatous disease (cgd). while there is evidence that defective macrophage autophagy in a mouse model of cf can influence b. cenocepacia susceptibility, there have been no comprehensive studies on how this bacteriu ...201324119232
the many uses of autophagosomes.autophagy has emerged as a significant innate immune response to pathogens. typically, autophagosomes deliver their contents to lysosomes for degradation. some pathogens such as salmonella enterica serovar typhimurium succumb to autophagy and are transported to lysosomes for degradation. yet, many professional pathogens, including legionella pneumophila and burkholderia cenocepacia, subvert this pathway exploiting autophagy to their advantage.201323507956
characterization of the atsr hybrid sensor kinase phosphorelay pathway and identification of its response regulator in burkholderia cenocepacia.atsr is a membrane-bound hybrid sensor kinase of burkholderia cenocepacia that negatively regulates quorum sensing and virulence factors such as biofilm production, type 6-secretion, and protease secretion. here we elucidate the mechanism of atsr phosphorelay by site-directed mutagenesis of predicted histidine and aspartic acid phosphoacceptor residues. we demonstrate by in vitro phosphorylation that histidine 245 and aspartic acid 536 are conserved sites of phosphorylation in atsr, and we also ...201324014026
response of burkholderia cenocepacia h111 to micro-oxia.b. cenocepacia is an opportunistic human pathogen that is particularly problematic for patients suffering from cystic fibrosis (cf). in the cf lung bacteria grow to high densities within the viscous mucus that is limited in oxygen. pseudomonas aeruginosa, the dominant pathogen in cf patients, is known to grow and survive under oxygen-limited to anaerobic conditions by using micro-oxic respiration, denitrification and fermentative pathways. in contrast, inspection of the genome sequences of avail ...201324023794
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