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genetic relationships among italian and mexican maize-rhizosphere burkholderia cepacia complex (bcc) populations belonging to burkholderia cenocepacia iiib and bcc6 group.abstract:201121995705
hopanoid production is required for low-ph tolerance, antimicrobial resistance, and motility in burkholderia cenocepacia.hopanoids are pentacyclic triterpenoids that are thought to be bacterial surrogates for eukaryotic sterols, such as cholesterol, acting to stabilize membranes and to regulate their fluidity and permeability. to date, very few studies have evaluated the role of hopanoids in bacterial physiology. the synthesis of hopanoids depends on the enzyme squalene-hopene cyclase (shc), which converts the linear squalene into the basic hopene structure. deletion of the 2 genes encoding shc enzymes in burkhold ...201121965564
Burkholderia cenocepacia disrupts host cell actin cytoskeleton by inactivating Rac and Cdc42.Burkholderia cenocepacia, a member of the Burkholderia cepacia complex, is an opportunistic pathogen that causes devastating infections in patients with cystic fibrosis. The ability of B. cenocepacia to survive within host cells could contribute significantly to its virulence in immunocompromised patients. In this study, we explored the mechanisms that enable B. cenocepacia to survive inside macrophages. We found that B. cenocepacia disrupts the actin cytoskeleton of infected macrophages, drast ...201122023324
the burkholderia cenocepacia bdsf quorum sensing fatty acid is synthesized by a bifunctional crotonase homologue having both dehydratase and thioesterase activities.signal molecules of the diffusible signal factor (dsf) family have been shown recently to be involved in regulation of pathogenesis and biofilm formation in diverse gram-negative bacteria. dsf signals are reported to be active not only on their cognate bacteria, but also on unrelated bacteria and the pathogenic yeast, candida albicans. dsfs are monounsaturated fatty acids of medium chain length containing an unusual cis-2 double bond. although genetic analyses had identified genes involved in ds ...201222221091
the genetic basis of cadmium resistance of burkholderia cenocepacia.burkholderia species are highly resistant to heavy metals (hms), yet their resistance mechanisms are largely unknown. in this study we screened 5000 mini-tn5 transposon insertion mutants of burkholderia cenocepacia h111 for loss of cadmium tolerance. of the four genes identified three affected outer membrane biogenesis and integrity or dna repair. the fourth gene, bcae0587, encoded a p1-type atpase belonging to the cada family of hm exporters. cada-deficient strains lost the ability to grow in t ...201223760902
comparative analysis of two phenotypically-similar but genomically-distinct burkholderia cenocepacia-specific bacteriophages.genomic analysis of bacteriophages infecting the burkholderia cepacia complex (bcc) is an important preliminary step in the development of a phage therapy protocol for these opportunistic pathogens. the objective of this study was to characterize kl1 (vb_bces_kl1) and ah2 (vb_bces_ah2), two novel burkholderia cenocepacia-specific siphoviruses isolated from environmental samples.201222676492
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
the novel cis-encoded small rna h2cr is a negative regulator of hfq2 in burkholderia cenocepacia.small non-coding regulatory rnas (srnas) post-transcriptionally affect multiple phenotypes in prokaryotes and eukaryotes, yet most of the underlying regulatory mechanisms and the nature of the target mrnas remain unclear. here we report the identification and functional analysis of the novel cis-encoded srna h2cr, from the human opportunistic pathogen burkholderia cenocepacia j2315. the srna was found to negatively regulate the hfq2 mrna, through binding to part of the 5'-utr region of the hfq2 ...201223082228
burkholderia cenocepacia differential gene expression during host-pathogen interactions and adaptation to the host environment.members of the burkholderia cepacia complex (bcc) are important in medical, biotechnological, and agricultural disciplines. these bacteria naturally occur in soil and water environments and have adapted to survive in association with plants and animals including humans. all bcc species are opportunistic pathogens including burkholderia cenocepacia that causes infections in cystic fibrosis and chronic granulomatous disease patients. the adaptation of b. cenocepacia to the host environment was ass ...201122919581
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
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
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
expression of phenazine biosynthetic genes during the arbuscular mycorrhizal symbiosis of glomus intraradices.to explore the molecular mechanisms that prevail during the establishment of the arbuscular mycorrhiza symbiosis involving the genus glomus, we transcriptionally analysed spores of glomus intraradices be3 during early hyphal growth. among 458 transcripts initially identified as being expressed at presymbiotic stages, 20% of sequences had homology to previously characterized eukaryotic genes, 30% were homologous to fungal coding sequences, and 9% showed homology to previously characterized bacter ...201224031884
agrobacteria lacking ornithine lipids induce more rapid tumour formation.ornithine lipids (ols) are phosphorus-free membrane lipids that are widespread among gram-negative bacteria. their basic structure consists of a 3-hydroxy fatty acyl group attached in amide linkage to the α-amino group of ornithine and a second fatty acyl group ester-linked to the 3-hydroxy position of the first fatty acid. it has been shown that ols can be hydroxylated within the amide-linked fatty acyl moiety, the secondary fatty acyl moiety or within the ornithine moiety. these modifications ...201222958119
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
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
activation of the pyrin inflammasome by intracellular burkholderia cenocepacia.burkholderia cenocepacia is an opportunistic pathogen that causes chronic infection and induces progressive respiratory inflammation in cystic fibrosis patients. recognition of bacteria by mononuclear cells generally results in the activation of caspase-1 and processing of il-1β, a major proinflammatory cytokine. in this study, we report that human pyrin is required to detect intracellular b. cenocepacia leading to il-1β processing and release. this inflammatory response involves the host adapte ...201222368275
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
host evasion by burkholderia cenocepacia.burkholderia cenocepacia is an opportunistic respiratory pathogen of individuals with cystic fibrosis (cf). some strains of b. cenocepacia are highly transmissible and resistant to almost all antibiotics. approximately one-third of b. cenocepacia infected cf patients go on to develop fatal "cepacia syndrome." during the last two decades, substantial progress has been made with regards to evasion of host innate defense mechanisms by b. cenocepacia. almost all strains of b. cenocepacia have the ca ...201122919590
can early burkholderia cepacia complex infection in cystic fibrosis be eradicated with antibiotic therapy?organisms of the burkholderia cepacia complex (bcc) are important pathogens in cystic fibrosis (cf). the majority of those who acquire bcc develop chronic infection but it can also result in rapid decline in a significant minority. in addition, chronic infection with burkholderia cenocepacia in particular is regarded as a contraindication to lung transplantation in many units. whilst aggressive antibiotic therapy is employed in cf to eradicate pseudomonas aeruginosa before infection becomes irre ...201122919584
genomic expression analysis reveals strategies of burkholderia cenocepacia to adapt to cystic fibrosis patients' airways and antimicrobial therapy.pulmonary colonization of cystic fibrosis (cf) patients with burkholderia cenocepacia or other bacteria of the burkholderia cepacia complex (bcc) is associated with worse prognosis and increased risk of death. during colonization, the bacteria may evolve under the stressing selection pressures exerted in the cf lung, in particular, those resulting from challenges of the host immune defenses, antimicrobial therapy, nutrient availability and oxygen limitation. understanding the adaptive mechanisms ...201122216120
3-hydroxyphenylacetic acid induces the burkholderia cenocepacia phenylacetic acid degradation pathway - toward understanding the contribution of aromatic catabolism to pathogenesis.the phenylacetic acid (pa) degradative pathway is the central pathway by which various aromatic compounds (e.g., styrene) are degraded. upper pathways for different aromatic compounds converge at common intermediate phenylacetyl-coa (pa-coa), which is then metabolized to succinyl-coa and acetyl-coa. we previously made a link in burkholderia cenocepacia between pa degradation and virulence by showing that insertional mutagenesis of paaa and paae genes, that encode part of a multicomponent oxidase ...201122919580
long-term colonization of the cystic fibrosis lung by burkholderia cepacia complex bacteria: epidemiology, clonal variation, and genome-wide expression alterations.long-term respiratory infections with burkholderia cepacia complex (bcc) bacteria in cystic fibrosis (cf) patients generally lead to a more rapid decline in lung function and, in some cases, to a fatal necrotizing pneumonia known as the "cepacia syndrome." bcc bacteria are ubiquitous in the environment and are recognized as serious opportunistic pathogens that are virtually impossible to eradicate from the cf lung, posing a serious clinical threat. the epidemiological survey of bcc bacteria invo ...201122919578
tangled bank of experimentally evolved burkholderia biofilms reflects selection during chronic infections.how diversity evolves and persists in biofilms is essential for understanding much of microbial life, including the uncertain dynamics of chronic infections. we developed a biofilm model enabling long-term selection for daily adherence to and dispersal from a plastic bead in a test tube. focusing on a pathogen of the cystic fibrosis lung, burkholderia cenocepacia, we sequenced clones and metagenomes to unravel the mutations and evolutionary forces responsible for adaptation and diversification o ...201223271804
the exopolysaccharide gene cluster bcam1330-bcam1341 is involved in burkholderia cenocepacia biofilm formation, and its expression is regulated by c-di-gmp and bcam1349.in burkholderia cenocepacia, the second messenger cyclic diguanosine monophosphate (c-di-gmp) has previously been shown to positively regulate biofilm formation and the expression of cellulose and type-i fimbriae genes through binding to the transcriptional regulator bcam1349. here, we provide evidence that cellulose and type-i fimbriae are not involved in b. cenocepacia biofilm formation in flow chambers, and we identify a novel bcam1349/c-di-gmp-regulated exopolysaccharide gene cluster which i ...201223281338
modelling co-infection of the cystic fibrosis lung by pseudomonas aeruginosa and burkholderia cenocepacia reveals influences on biofilm formation and host response.the gram-negative bacteria pseudomonas aeruginosa and burkholderia cenocepacia are opportunistic human pathogens that are responsible for severe nosocomial infections in immunocompromised patients and those suffering from cystic fibrosis (cf). these two bacteria have been shown to form biofilms in the airways of cf patients that make such infections more difficult to treat. only recently have scientists begun to appreciate the complicated interplay between microorganisms during polymicrobial inf ...201223284990
the ahl- and bdsf-dependent quorum sensing systems control specific and overlapping sets of genes in burkholderia cenocepacia h111.quorum sensing in burkholderia cenocepacia h111 involves two signalling systems that depend on different signal molecules, namely n-acyl homoserine lactones (ahls) and the diffusible signal factor cis-2-dodecenoic acid (bdsf). previous studies have shown that ahls and bdsf control similar phenotypic traits, including biofilm formation, proteolytic activity and pathogenicity. in this study we mapped the bdsf stimulon by rna-seq and shotgun proteomics analysis. we demonstrate that a set of the ide ...201223185499
a luxr-type repressor of burkholderia cenocepacia inhibits transcription via antiactivation and is inactivated by its cognate acylhomoserine lactone.burkholderia cenocepacia is an opportunistic human pathogen that encodes two luxi-type acylhomoserine lactone (ahl) synthases and three luxr-type ahl receptors. of these, cepi and cepr form a cognate synthase/receptor pair, as do ccii and ccir, while cepr2 lacks a genetically linked ahl synthase gene. another group showed that a cepr2 mutant overexpressed a cluster of linked genes that appear to direct the production of a secondary metabolite. we found that these same genes were upregulated by o ...201223136852
burkholderia cenocepacia bacteremia without respiratory colonization in an adult intensive care unit: epidemiological and molecular investigation of an outbreak.to investigate an outbreak of burkholderia cenocepacia bacteremia. observational study and chart review in a multidisciplinary adult intensive care unit (icu) at a tertiary care hospital.201223935310
burkholderia cenocepacia type vi secretion system mediates escape of type ii secreted proteins into the cytoplasm of infected macrophages.burkholderia cenocepacia is an opportunistic pathogen that survives intracellularly in macrophages and causes serious respiratory infections in patients with cystic fibrosis. we have previously shown that bacterial survival occurs in bacteria-containing membrane vacuoles (bccvs) resembling arrested autophagosomes. intracellular bacteria stimulate il-1β secretion in a caspase-1-dependent manner and induce dramatic changes to the actin cytoskeleton and the assembly of the nadph oxidase complex ont ...201222848580
a bcam0223 mutant of burkholderia cenocepacia is deficient in hemagglutination, serum resistance, adhesion to epithelial cells and virulence.burkholderia cepacia complex (bcc) bacteria are a problematic group of microorganisms causing severe infections in patients with cystic fibrosis. in early stages of infection, bcc bacteria must be able to adhere to and colonize the respiratory epithelium. although this is not fully understood, this primary stage of infection is believed to be in part mediated by a specific type of adhesins, named trimeric autotransporter adhesins (taas). these homotrimeric proteins exist on the surface of many g ...201222848588
centromere binding and evolution of chromosomal partition systems in the burkholderiales.how split genomes arise and evolve in bacteria is poorly understood. since each replicon of such genomes encodes a specific partition (par) system, the evolution of par systems could shed light on their evolution. the cystic fibrosis pathogen burkholderia cenocepacia has three chromosomes (c1, c2, and c3) and one plasmid (pbc), whose compatibility depends on strictly specific interactions of the centromere sequences (pars) with their cognate binding proteins (parb). however, the par systems of b ...201222522899
high confidence prediction of essential genes in burkholderia cenocepacia.essential genes are absolutely required for the survival of an organism. the identification of essential genes, besides being one of the most fundamental questions in biology, is also of interest for the emerging science of synthetic biology and for the development of novel antimicrobials. new antimicrobial therapies are desperately needed to treat multidrug-resistant pathogens, such as members of the burkholderia cepacia complex.201222768221
exaggerated inflammatory responses mediated by burkholderia cenocepacia in human macrophages derived from cystic fibrosis patients.cystic fibrosis (cf) is accompanied with heightened inflammation worsened by drug resistant burkholderia cenocepacia. human cf macrophage responses to b. cenocepacia are poorly characterized and variable in the literature. therefore, we examined human macrophage responses to the epidemic b. cenocepacia j2315 strain in order to identify novel anti-inflammatory targets. peripheral blood monocyte derived macrophages were obtained from 23 cf and 27 non-cf donors. macrophages were infected with b. ce ...201222728038
identification of functions linking quorum sensing with biofilm formation in burkholderia cenocepacia h111.burkholderia cenocepacia has emerged as an important pathogen for patients suffering from cystic fibrosis (cf). previous work has shown that this organism employs the cepir quorum-sensing (qs) system to control the expression of virulence factors as well as the formation of biofilms. to date, however, very little is known about the qs-regulated virulence factors and virtually nothing about the factors that link qs and biofilm formation. here, we have employed a combined transcriptomic and proteo ...201222950027
a unique regulator contributes to quorum sensing and virulence in burkholderia cenocepacia.burkholderia cenocepacia causes chronic and life-threatening respiratory infections in immunocompromized people. the b. cenocepacia n-acyl-homoserine lactone (ahl)-dependent quorum sensing system relies on the production of ahls by the synthases cepi and ccii while cepr, ccir and cepr2 control expression of many genes important for pathogenesis. downstream from, and co-transcribed with cepi, lies bcam1871 encoding a hypothetical protein that was uncharacterized prior to this study. orthologs of ...201222624054
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
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
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
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
genomic characterization of jg068, a novel virulent podovirus active against burkholderia cenocepacia.as is true for many other antibiotic-resistant gram-negative pathogens, members of the burkholderia cepacia complex (bcc) are currently being assessed for their susceptibility to phage therapy as an antimicrobial treatment. the objective of this study was to perform genomic and limited functional characterization of the novel bcc phage jg068 (vb_bcep_jg068).201323978260
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
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
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
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
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
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
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
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
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
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
activity of tobramycin against cystic fibrosis isolates of burkholderia cepacia complex grown as biofilms.pulmonary infection with burkholderia cepacia complex in cystic fibrosis (cf) patients is associated with more-rapid lung function decline and earlier death than in cf patients without this infection. in this study, we used confocal microscopy to visualize the effects of various concentrations of tobramycin, achievable with systemic and aerosolized drug administration, on mature b. cepacia complex biofilms, both in the presence and absence of cf sputum. after 24 h of growth, biofilm thickness wa ...201526503664
clinafloxacin for treatment of burkholderia cenocepacia infection in a cystic fibrosis patient.respiratory infection with burkholderia cenocepacia is associated with accelerated decline in lung function and increased mortality in cystic fibrosis (cf) patients (a. m. jones, m. e. dodd, j. r. w. govan, v. barcus, c. j. doherty, j. morris, and a. k. webb, thorax 59:948-951, 2004, http://dx.doi.org/10.1136/thx.2003.017210). b. cenocepacia often possesses innate resistance to multiple antimicrobial classes, making eradication uncommon in established infection (p. b. davis, am j respir crit car ...201526722110
cell wall recycling-linked coregulation of ampc and penb β-lactamases through ampd mutations in burkholderia cenocepacia.in many gram-negative pathogens, mutations in the key cell wall-recycling enzyme ampd (n-acetyl-anhydromuramyl-l-alanine amidase) affect the activity of the regulator ampr, which leads to the expression of ampc β-lactamase, conferring resistance to expanded-spectrum cephalosporin antibiotics. burkholderia cepacia complex (bcc) species also have these amp homologs; however, the regulatory circuitry and the nature of causal ampd mutations remain to be explored. a total of 92 ampd mutants were obta ...201526416862
genome-wide transcription start site profiling in biofilm-grown burkholderia cenocepacia j2315.burkholderia cenocepacia is a soil-dwelling gram-negative betaproteobacterium with an important role as opportunistic pathogen in humans. infections with b. cenocepacia are very difficult to treat due to their high intrinsic resistance to most antibiotics. biofilm formation further adds to their antibiotic resistance. b. cenocepacia harbours a large, multi-replicon genome with a high gc-content, the reference genome of strain j2315 includes 7374 annotated genes. this study aims to annotate trans ...201526462475
the dsf family of cell-cell signals: an expanding class of bacterial virulence regulators.many pathogenic bacteria use cell-cell signaling systems involving the synthesis and perception of diffusible signal molecules to control virulence as a response to cell density or confinement to niches. bacteria produce signals of diverse structural classes. signal molecules of the diffusible signal factor (dsf) family are cis-2-unsaturated fatty acids. the paradigm is cis-11-methyl-2-dodecenoic acid from xanthomonas campestris pv. campestris (xcc), which controls virulence in this plant pathog ...201526181439
a pipeline for screening small molecules with growth inhibitory activity against burkholderia cenocepacia.infections with the bacteria burkholderia cepacia complex (bcc) are very difficult to eradicate in cystic fibrosis patients due the intrinsic resistance of bcc to most available antibiotics and the emergence of multiple antibiotic resistant strains during antibiotic treatment. in this work, we used a whole-cell based assay to screen a diverse collection of small molecules for growth inhibitors of a relevant strain of bcc, b. cenocepacia k56-2. the primary screen used bacterial growth in 96-well ...201526053039
burkholderia cenocepacia lipopolysaccharide modification and flagellin glycosylation affect virulence but not innate immune recognition in plants.burkholderia cenocepacia causes opportunistic infections in plants, insects, animals, and humans, suggesting that "virulence" depends on the host and its innate susceptibility to infection. we hypothesized that modifications in key bacterial molecules recognized by the innate immune system modulate host responses to b. cenocepacia. indeed, modification of lipopolysaccharide (lps) with 4-amino-4-deoxy-l-arabinose and flagellin glycosylation attenuates b. cenocepacia infection in arabidopsis thali ...201526045541
the variability of the order burkholderiales representatives in the healthcare units.the order burkholderiales became more abundant in the healthcare units since the late 1970s; it is especially dangerous for intensive care unit patients and patients with chronic lung diseases. the goal of this investigation was to reveal the real variability of the order burkholderiales representatives and to estimate their phylogenetic relationships.201526114111
σ54-dependent response to nitrogen limitation and virulence in burkholderia cenocepacia strain h111.members of the genus burkholderia are versatile bacteria capable of colonizing highly diverse environmental niches. in this study, we investigated the global response of the opportunistic pathogen burkholderia cenocepacia h111 to nitrogen limitation at the transcript and protein expression levels. in addition to a classical response to nitrogen starvation, including the activation of glutamine synthetase, pii proteins, and the two-component regulatory system ntrbc, b. cenocepacia h111 also upreg ...201525841012
in-frame and unmarked gene deletions in burkholderia cenocepacia via an allelic exchange system compatible with gateway technology.burkholderia cenocepacia is an emerging opportunistic pathogen causing life-threatening infections in immunocompromised individuals and in patients with cystic fibrosis, which are often difficult, if not impossible, to treat. understanding the genetic basis of virulence in this emerging pathogen is important for the development of novel treatment regimes. generation of deletion mutations in genes predicted to encode virulence determinants is fundamental to investigating the mechanisms of pathoge ...201525795676
efflux pump-mediated drug resistance in burkholderia.several members of the genus burkholderia are prominent pathogens. infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. virtually all burkholderia species are also resistant to polymyxin, prohibiting use of drugs like colistin that are available for treatment of infections caused by most other drug resistant gram-negative bacteria. despite clinical significance and antibiotic resistance of burkholderia species, characterization of efflux pumps la ...201525926825
gene expression profiling of burkholderia cenocepacia at the time of cepacia syndrome: loss of motility as a marker of poor prognosis?cepacia syndrome (cs) is a fatal septic condition that develops in approximately 20% of cystic fibrosis (cf) patients chronically infected with the burkholderia cepacia complex (bcc). the most common causative agent is burkholderia cenocepacia, a clinically dominant bcc species that contains the globally distributed epidemic strain sequence type 32 (st32). using microarrays, we compared the transcriptomes of st32 isolates from the bloodstream at the time of cs with their sputum counterparts reco ...201525694518
there and back again: consequences of biofilm specialization under selection for dispersal.experimental evolution paired with modern sequencing can be a powerful approach to identify the mechanisms by which bacteria adapt to discrete environmental conditions found in nature or during infections. we used this approach to identify mechanisms enabling biofilm specialists of the opportunistic respiratory pathogen burkholderia cenocepacia to regain planktonic fitness. seven mutants producing wrinkly (w) small-colony variants by mutations in the wrinkly-spreader operon (wsp) cluster, but wi ...201525717335
(1)h-nmr-based endometabolome profiles of burkholderia cenocepacia clonal variants retrieved from a cystic fibrosis patient during chronic infection.during cystic fibrosis (cf) chronic lung infections, bacteria of the burkholderia cepacia complex (bcc) are exposed for several years to a stressful and changing environment. these environmental challenges results in genetic changes of the initial infecting strain with the consequent diversification of genotypes and phenotypes. the exploitation of functional and comparative genomic approaches has suggested that such diversification is associated with massive metabolic remodeling but these altera ...201628066350
biochemical characterization of glutamate racemase-a new candidate drug target against burkholderia cenocepacia infections.the greatest obstacle for the treatment of cystic fibrosis patients infected with the burkholderia species is their intrinsic antibiotic resistance. for this reason, there is a need to develop new effective compounds. glutamate racemase, an essential enzyme for the biosynthesis of the bacterial cell wall, is an excellent candidate target for the design of new antibacterial drugs. to this aim, we recombinantly produced and characterized glutamate racemase from burkholderia cenocepacia j2315. from ...201627898711
a novel method for investigating burkholderia cenocepacia infections in patients with cystic fibrosis and other chronic diseases of the airways.burkholderia cenocepacia is a gram-negative, opportunistic pathogen that is a cause of morbidity and mortality in patients with cystic fibrosis (cf). research efforts over the past few decades contributed to our understanding of these infections by identifying virulence factors. however, little is known about how this pathogen adapts to the harsh environment found inside the cf airways, which is characterized by a unique mucus containing high concentrations of inflammatory markers. the current s ...201627586172
discovery of new diketopiperazines inhibiting burkholderia cenocepacia quorum sensing in vitro and in vivo.burkholderia cenocepacia, an opportunistic respiratory pathogen particularly relevant for cystic fibrosis patients, is difficult to eradicate due to its high level of resistance to most clinically relevant antimicrobials. consequently, the discovery of new antimicrobials as well as molecules capable of inhibiting its virulence is mandatory. in this regard quorum sensing (qs) represents a good target for anti-virulence therapies, as it has been linked to biofilm formation and is important for the ...201627580679
candidate essential genes in burkholderia cenocepacia j2315 identified by genome-wide tradis.burkholderia cenocepacia infection often leads to fatal cepacia syndrome in cystic fibrosis patients. however, antibiotic therapy rarely results in complete eradication of the pathogen due to its intrinsic resistance to many clinically available antibiotics. recent attention has turned to the identification of essential genes as the proteins encoded by these genes may serve as potential targets for development of novel antimicrobials. in this study, we utilized tradis (transposon directed insert ...201627597847
the role of reactive oxygen species in antibiotic-induced cell death in burkholderia cepacia complex bacteria.it was recently proposed that bactericidal antibiotics, besides through specific drug-target interactions, kill bacteria by a common mechanism involving the production of reactive oxygen species (ros). however, this mechanism involving the production of hydroxyl radicals has become the subject of a lot of debate. since the contribution of ros to antibiotic mediated killing most likely depends on the conditions, differences in experimental procedures are expected to be at the basis of the conflic ...201627438061
the burkholderia cenocepacia ompa-like protein bcal2958: identification, characterization, and detection of anti-bcal2958 antibodies in serum from b. cepacia complex-infected cystic fibrosis patients.respiratory infections by bacteria of the burkholderia cepacia complex (bcc) remain an important cause of morbidity and mortality among cystic fibrosis patients, highlighting the need for novel therapeutic strategies. in the present work we have studied the b. cenocepacia protein bcal2958, a member of the ompa-like family of proteins, demonstrated as highly immunogenic in other pathogens and capable of eliciting strong host immune responses. the encoding gene was cloned and the protein, produced ...201627325348
synthetic cystic fibrosis sputum medium regulates flagellar biosynthesis through the flhf gene in burkholderia cenocepacia.burkholderia cenocepacia belongs to the burkholderia cepacia complex (bcc), a group of at least 18 distinct species that establish chronic infections in the lung of people with the genetic disease cystic fibrosis (cf). the sputum of cf patients is rich in amino acids and was previously shown to increase flagellar gene expression in b. cenocepacia. we examined flagellin expression and flagellar morphology of b. cenocepacia grown in synthetic cystic fibrosis sputum medium (scfm) compared to minima ...201627379216
cyanide toxicity to burkholderia cenocepacia is modulated by polymicrobial communities and environmental factors.microbes within polymicrobial communities can establish positive and negative interactions that have the potential to influence the overall behavior of the community. pseudomonas aeruginosa and species of the burkholderia cepacia complex (bcc) can co-exist in the lower airways, however several studies have shown that p. aeruginosa can effectively kill the bcc in vitro, for which hydrogen cyanide (hcn) was recently proposed to play a critical role. here we show that modification of the environmen ...201627242743
structural features essential to the antimicrobial functions of human splunc1.splunc1 is an abundantly secreted innate immune protein in the mammalian respiratory tract that exerts bacteriostatic and antibiofilm effects, binds to lipopolysaccharide (lps), and acts as a fluid-spreading surfactant. here, we unravel the structural elements essential for the surfactant and antimicrobial functions of human splunc1 (short palate lung nasal epithelial clone 1). a unique α-helix (α4) that extends from the body of splunc1 is required for the bacteriostatic, surfactant, and lps bin ...201627145151
draft genome sequence of burkholderia cenocepacia strain ceib s5-2, a methyl parathion- and p-nitrophenol-degrading bacterium, isolated from agricultural soils in morelos, mexico.burkholderia cenocepacia is an opportunistic pathogen that belongs to burkholderia cepacia complex (bcc). burkholderia cenocepacia strain ceib s5-2 was isolated from agricultural soils in morelos, mexico, and previously has shown its abilities for bioremediation. in this study, we report the draft genome sequence of burkholderia cenocepacia strain ceib s5-2.201627125479
linocin and ompw are involved in attachment of the cystic fibrosis-associated pathogen burkholderia cepacia complex to lung epithelial cells and protect mice against infection.members of the burkholderia cepacia complex (bcc) cause chronic opportunistic lung infections in people with cystic fibrosis (cf), resulting in a gradual lung function decline and, ultimately, patient death. the bcc is a complex of 20 species and is rarely eradicated once a patient is colonized; therefore, vaccination may represent a better therapeutic option. we developed a new proteomics approach to identify bacterial proteins that are involved in the attachment of bcc bacteria to lung epithel ...201626902727
tyrosine phosphorylation and dephosphorylation in burkholderia cenocepacia affect biofilm formation, growth under nutritional deprivation, and pathogenicity.burkholderia cenocepacia, a member of the b. cepacia complex (bcc), is an opportunistic pathogen causing serious chronic infections in patients with cystic fibrosis. tyrosine phosphorylation has emerged as an important posttranslational modification modulating the physiology and pathogenicity of bcc bacteria. here, we investigated the predicted bacterial tyrosine kinases bcam1331 and bcef and the low-molecular-weight protein tyrosine phosphatases bcam0208, bced, and bcal2200 of b. cenocepacia k5 ...201626590274
polyphasic characterisation of burkholderia cepaciacomplex species isolated from children with cystic fibrosis.cystic fibrosis (cf) patients with burkholderia cepacia complex (bcc) pulmonary infections have high morbidity and mortality. the aim of this study was to compare different methods for identification of bcc species isolated from paediatric cf patients. oropharyngeal swabs from children with cf were used to obtain isolates of bcc samples to evaluate six different tests for strain identification. conventional (cpt) and automatised (apt) phenotypic tests, polymerase chain reaction (pcr)-reca, restr ...201626814642
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
genome-scale ncrna homology search using a hamming distance-based filtration strategy.ncrnas (noncoding rnas) play important roles in many biological processes. existing genome-scale ncrna search tools identify ncrnas in local sequence alignments generated by conventional sequence comparison methods. however, some types of ncrna lack strong sequence conservation and tend to be missed or mis-aligned by conventional sequence comparison.201222536896
cis-2-dodecenoic acid receptor rpfr links quorum-sensing signal perception with regulation of virulence through cyclic dimeric guanosine monophosphate turnover.many bacterial pathogens produce diffusible signal factor (dsf)-type quorum sensing (qs) signals in modulation of virulence and biofilm formation. previous work on xanthomonas campestris showed that the rpfc/rpfg two-component system is involved in sensing and responding to dsf signals, but little is known in other microorganisms. here we show that in burkholderia cenocepacia the dsf-family signal cis-2-dodecenoic acid (bdsf) negatively controls the intracellular cyclic dimeric guanosine monopho ...201222949660
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
the host plant metabolite glucose is the precursor of diffusible signal factor (dsf) family signals in xanthomonas campestris.plant pathogen xanthomonas campestris pv. campestris produces cis-11-methyl-2-dodecenoic acid (diffusible signal factor [dsf]) as a cell-cell communication signal to regulate biofilm dispersal and virulence factor production. previous studies have demonstrated that dsf biosynthesis is dependent on the presence of rpff, an enoyl-coenzyme a (coa) hydratase, but the dsf synthetic mechanism and the influence of the host plant on dsf biosynthesis are still not clear. we show here that exogenous addit ...201525681189
structural differences in gut bacteria communities in developmental stages of natural populations of lutzomyia evansi from colombia's caribbean coast.lutzomyia evansi, a phlebotomine insect endemic to colombia's caribbean coast, is considered to be the main vector of visceral and cutaneous leishmaniasis in the region. although insects of this species can harbor pathogenic and non-pathogenic microorganisms in their intestinal microbiota, there is little information available about the diversity of gut bacteria present in lutzomyia evansi. in this study, conventional microbiological methods and molecular tools were used to assess the compositio ...201627618991
the dsf type quorum sensing signalling system rpff/r regulates diverse phenotypes in the opportunistic pathogen cronobacter.several bacterial pathogens produce diffusible signal factor (dsf)-type quorum sensing (qs) signals to control biofilm formation and virulence. previous work showed that in burkholderia cenocepacia the rpffbc/rpfr system is involved in sensing and responding to dsf signals and that this signal/sensor gene pair is highly conserved in several bacterial species including cronobacter spp. here we show that c. turicensis lmg 23827(t) possesses a functional rpff/r system that is involved in the regula ...201626725701
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