Response of Burkholderia cenocepacia H111 to micro-oxia
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ABSTRACT: 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 available B. cenocepacia strains suggested that B. cenocepacia is an obligate aerobic and non-fermenting bacterium. In accordance with the bioinformatics analysis, we observed that B. cenocepacia H111 is able to grow with as little as 0.1% O2 but not under strictly anoxic conditions. Phenotypic analyses revealed that H111 produced larger amounts of biofilm, pellicle and proteases under micro-oxic conditions (0.5% - 5% O2, i.e. conditions that mimic those encountered in CF lung infection), and was more resistant to several antibiotics. RNA-Seq and shotgun proteomics analyses of cultures of B. cenocepacia H111 grown under micro-oxic and aerobic conditions showed up-regulation of genes involved in the synthesis of the exopolysaccharide (EPS) cepacian as well as several proteases, two isocitrate lyases and other genes potentially important for life in micro-oxia.
Project description: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 available B. cenocepacia strains suggested that B. cenocepacia is an obligate aerobic and non-fermenting bacterium. In accordance with the bioinformatics analysis, we observed that B. cenocepacia H111 is able to grow with as little as 0.1% O2 but not under strictly anoxic conditions. Phenotypic analyses revealed that H111 produced larger amounts of biofilm, pellicle and proteases under micro-oxic conditions (0.5% - 5% O2, i.e. conditions that mimic those encountered in CF lung infection), and was more resistant to several antibiotics. RNA-Seq and shotgun proteomics analyses of cultures of B. cenocepacia H111 grown under micro-oxic and aerobic conditions showed up-regulation of genes involved in the synthesis of the exopolysaccharide (EPS) cepacian as well as several proteases, two isocitrate lyases and other genes potentially important for life in micro-oxia. Oxygen regulation in Burkholderia cenocepacia was investigated using RNA-Seq of cells grown under aerobic or micro-oxic conditions.
Project description:Using a discovery shotgun proteomics approach, the expressed proteome of Burkholderia cenocepacia (strain H111) under aerobic (21% oxygen) and micro-oxic (0.5% oxygen) conditions was analyzed. B.cenocepacia is an opportunistic human pathogen that is particularly problematic for patients suffering from cystic fibrosis. Cells were sub-cellular fractionated (Cyt=cytoplasmic, TM=total membrane, EC=extracellular) and proteins were extracted and separated by 1D SDS-PAGE. Gels were cut into ten slices, digested using trypsin and resulting peptides were analyzed using LC-MS/MS once with a discovery run followed by a subsequent exclusion list run (precursor ions identified in the discovery run were excluded from fragmentation in the exclusion run). Mass spectra were searched against a protein sequence database containing 7258 annotated B. cenocepacia H111 proteins (accession CAFQ00000000.1) and protein sequences of 259 common contaminants. Spectra were searched against this database with MS-GF+ (MS-GFDB v7747, kindly provided by Dr. Sangtae Kim, UCSD, USA) using the following parameters: Carbamidomethylation was set as a fixed modification on all Cysteines, oxidation of Methionines, deamidation of Asparagines and Glutamines, as well as cyclization of N-terminal Glutamines were considered as optional modifications. Spectra were searched for a match to fully-tryptic and semi-tryptic peptides and the automatic decoy search option was enabled. Search results were filtered and summarized using in-house tools. A total of 2,128 proteins was identified at an estimated FDR of less than 1%. Additional RNA-seq data are held at GEO under the accession: GSE48585.
Project description:Using a discovery shotgun proteomics approach, the expressed proteome of Burkholderia cenocepacia (strain H111) was analyzed under normal and starved nitrogen growth conditions. B. cenocepacia is an opportunistic human pathogen that is particularly problematic for patients suffering from cystic fibrosis.
Project description:[1] Transcription profiling of one Burkholderia cenocepacia clinical isolate, J2315, versus a soil isolate, HI2424, in conditions mimicking CF sputum [2] Transcription profiling of Burkholderia cenocepacia isolates J2315 and HI2424 in media mimicking CF sputum or the soil environment
Project description:Comparative transcriptional profiling of the Burkholderia cenocepacia H111 wild type, the cepR mutant H111-R and the complemented cepR mutant H111-R (pBAH27).
Project description:[1] Transcription profiling of one Burkholderia cenocepacia clinical isolate, J2315, versus a soil isolate, HI2424, in conditions mimicking CF sputum [2] Transcription profiling of Burkholderia cenocepacia isolates J2315 and HI2424 in media mimicking CF sputum or the soil environment [1] J2315 vs. HI2424 cells in the same condition. [2] Two-condition experiment. Biological replicates: 4 replicates.
Project description: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 level. 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 up-regulated polyhydroxybutyrate (PHB) accumulation and exopolysaccharide (EPS) production in response to nitrogen shortage. A search for consensus sequences in promoter regions of nitrogen responsive genes identified a s54 consensus sequence. The mapping of the s54 regulon as well as the characterization of a s54 mutant suggests an important role of s54 not only in control of nitrogen metabolism, but also in virulence of this organism.
Project description:Burkholderia cenocepacia sequence type 32 (ST32) represents one of the most globally distributed strains from Bukrholderia cepacia complex (Bcc), which infected 30% of Czech cystic fibrosis (CF) patients. The aim of this study was to compare gene expression in two pairs of ST32 clinical isolates that were subjected to cultivation in two different conditions, characteristic for chronic B. cenocepacia infection in CF patients. ST32 strain is known to be a problematic epidemic strain, which caused a serious outbreak at the Prague CF centre.
Project description:P. falciparum NF54 proliferates under micro-aerophilic conditions in an environment of 3% O2, 4% CO2, 93% N2. This strain was gradually adapted to proliferate under standard tissue culture conditions of 5% CO2/95% air (~19% O2) to generate P. falciparum HOX. We compared global gene expression profiles of the two strains to identify differences, if any.