Transcription profiling of P. aeruginosa glutamate mediated biofilm dispersion
Ontology highlight
ABSTRACT:
ORGANISM(S): Pseudomonas aeruginosa
SUBMITTER: Alexander Rickard
PROVIDER: E-MEXP-87 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Publications
Characterization of nutrient-induced dispersion in Pseudomonas aeruginosa PAO1 biofilm.
Sauer K K Cullen M C MC Rickard A H AH Zeef L A H LA Davies D G DG Gilbert P P
Journal of bacteriology 20041101 21
The processes associated with early events in biofilm formation have become a major research focus over the past several years. Events associated with dispersion of cells from late stage biofilms have, however, received little attention. We demonstrate here that dispersal of Pseudomonas aeruginosa PAO1 from biofilms is inducible by a sudden increase in carbon substrate availability. Most efficient at inducing dispersal were sudden increases in availability of succinate > glutamate > glucose that ...[more]
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Project description:Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics. To gain insights into the physiology of P. aeruginosa during infection, we assessed the transcriptional programs of three different P. aeruginosa strains directly after isolation from burn wounds of humans. We compared the programs to those of the same strains using two infection models: a plant model, which consisted of the infection of the midrib of lettuce leaves, and a murine tumor model, which was obtained by infection of mice with an induced tumor in the abdomen. All control conditions of P. aeruginosa cells growing in suspension and as a biofilm were added to the analysis. We found that these different P. aeruginosa strains express a pool of distinct genetic traits that are activated under particular infection conditions regardless of their genetic variability. The knowledge herein generated will advance our understanding of P. aeruginosa virulence and provide valuable cues for the definition of prospective targets to develop novel intervention strategies. Samples collected from human burn wounds were stabilized and used for P. aeruginosa RNA extraction. The strains from burn wound infection were later used for infection models namely plant and murine tumor infection as well as rich medium controls with planctonic and biofilm growth. The RNA was treated for bacterial RNA enrichment and amplification. All samples were treated in the same way.
2011-09-19 | E-GEOD-23007 | biostudies-arrayexpress
Project description:A hallmark of the biofilm architecture is the presence of microcolonies. However, little is known about the underlying mechanisms governing microcolony formation. In the human pathogen Pseudomonas aeruginosa, microcolony formation is dependent on the two-component regulator MifR, with mifR mutant biofilms exhibiting an overall thin structure lacking microcolonies, and overexpression of mifR resulting in hyper-microcolony formation. Here, we made use of the distinct MifR-dependent phenotypes to elucidate mechanisms associated with microcolony formation. Using global transcriptomic and proteomic approaches, we demonstrate that cells located within microcolonies experience stressful, oxygen limited, and energy starving conditions, as indicated by the activation of stress response mechanisms and anaerobic and fermentative processes, in particular pyruvate fermentation. Inactivation of genes involved in pyruvate utilization including uspK, acnA and ldhA abrogated microcolony formation in a manner similar to mifR inactivation. Moreover, depletion of pyruvate from the growth medium impaired biofilm and microcolony formation, while addition of pyruvate significantly increased microcolony formation. Addition of pyruvate partly restored microcolony formation in M-bM-^HM-^FmifR biofilms. Moreover, addition of pyruvate to or expression of mifR in lactate dehydrogenase (ldhA) mutant biofilms did not restore microcolony formation. Consistent with the finding of denitrification genes not demonstrating distinct expression patterns in biofilms forming or lacking microcolonies, addition of nitrate did not alter microcolony formation. Our findings indicate the fermentative utilization of pyruvate to be a microcolony-specific adaptation to the oxygen limitation and energy starvation of the P. aeruginosa biofilm environment. For biofilm growth experiments, three independent replicates of P. aeruginosa strains PAO1 and M-NM-^TmifR were grown as biofilms in a flow-through system using a once-through continuous flow tube reactor system for biofilm sample collection and in flow cells (BioSurface Technologies) for the analysis of biofilm architecture as previously described (Sauer et al., 2002, Sauer et al., 2004, Petrova & Sauer, 2009). Cells were treated with RNAprotect (Qiagen) and total RNA was extracted using an RNeasy mini purification kit (Qiagen) per the manufacturerM-bM-^@M-^Ys instructions. RNA quality and the presence of residual DNA were checked on an Agilent Bioanalyzer 2100 electrophoretic system pre- and post-DNase treatment. Ten micrograms of total RNA was used for cDNA synthesis, fragmentation, and labeling according to the Affymetrix GeneChip P. aeruginosa genome array expression analysis protocol. Sauer, K., A. K. Camper, G. D. Ehrlich, J. W. Costerton & D. G. Davies, (2002) Pseudomonas aeruginosa displays multiple phenotypes during development as a biofilm. J. Bacteriol. 184: 1140-1154. Sauer, K., M. C. Cullen, A. H. Rickard, L. A. H. Zeef, D. G. Davies & P. Gilbert, (2004) Characterization of nutrient-induced dispersion in Pseudomonas aeruginosa PAO1 biofilm. J. Bacteriol. 186: 7312-7326. Petrova, O. E. & K. Sauer, (2009) A novel signaling network essential for regulating Pseudomonas aeruginosa biofilm development. PLoS Pathogens 5: e1000668.
2012-04-30 | E-GEOD-35286 | biostudies-arrayexpress
Project description:Cell-selective BONCAT analysis of proteins synthesized by a P. aeruginosa biofilm subpopulation throughout treatment with ciprofloxacin.
2017-10-24 | PXD007261 | Pride
Project description:In the present in vitro study, interactions between P. aeruginosa (sessile biofilms as well as planktonic cells) and PMNs were analyzed by means of DNA microarray based transcriptomics. We found that the P. aeruginosa wild type biofilms, in contrast to planktonic cultures and quorum sensing (QS) deficient strains, respond to PMN exposure in a rather aggressive manner. The response does not involve protective mechanisms such as those involved in oxidative stress. Rather it is dominated by QS controlled virulence determinants such as those encoded by pqs, phz, rhlAB, all of which are designed to cripple Eukaryotic cells including PMNs and macrophages. Our comparative analysis supports the view that QS plays a major role in mechanisms by which P. aeruginosa evades host defense systems. Keywords: Stress response The biofilms were allowed to grow and develop in the biofilm flow chambers for 3 days before challenge with PMNs. Fresh PMNs from human volunteers were isolated and resuspended in RPMI-1640 medium (BIOCHROM AG) as previously described by Bjarnsholt et al. 2005 (Bjarnsholt et al., 2005). Prior to PMN injection the flow was halted. Ten million PMNs were resuspended in 6 ml of RPMI media and injected into the flow chamber. The concentration of PMNs was found by microscopy to be approximately 1 PMN per 1000 bacterial cells. PMNs and biofilm were incubated for 2 hours. The flow chambers were rolled every 15 minutes to ensure that the entire biofilm was exposed to the PMNs. After incubation the fluid inside the chamber was discarded and the attached biofilm cells were loosened by rolling. The cells were then mechanically removed and collected in 6 ml of RNAlater®
2009-08-04 | E-GEOD-6769 | biostudies-arrayexpress
Project description:Cell-selective BONCAT analysis of proteins synthesized by two P. aeruginosa biofilm subpopulations.
2017-10-24 | PXD007622 | Pride
Project description:Pseudomonas aeruginosa biofilms were dispersed spontaneously, with 18 mM glutamate, 500 uM SNP, by stopping the flow for 1 hour and restarting it or via vapor nanobubbles.
2020-08-28 | E-MTAB-8354 | biostudies-arrayexpress
Project description:Background: Biofilm formation by Salmonella species enhances the capacity of these pathogenic bacteria to survive stresses that are commonly encountered within food processing and during host infection. The persistence of Salmonella within the food chain has become a major health concern, as biofilms can serve as a reservoir to contaminate food products. While the molecular mechanisms required for the survival of bacteria on surfaces are not fully understood, transcriptional studies of other bacteria have demonstrated that biofilm growth triggers the expression of specific sets of genes, compared with planktonic cells. Until now, most transcriptomic studies of Salmonella have focused on the effect of infection-relevant stressors on virulence and on comparing mutant and wild-type (WT). However little is known about the physiological responses taking place inside a Salmonella biofilm. Results: We have determined the transcriptomic and proteomic profiles of biofilms of Salmonella enterica serovar Typhimurium. We discovered that 124 of detectable proteins were differentially expressed in the biofilm compared with planktonic cells, and that 10% (433 genes) of S. Typhimurium genes showed a biofilm-specific pattern of transcription (i.e. a 2-fold or more change in the biofilm compared with planktonic cells). The genes that were significantly up-regulated implicated specific cellular processes in biofilm development including amino acid metabolism, cell motility, global regulation and tolerance to stress. We found that the most highly down-regulated genes in the biofilm were located on Salmonella Pathogenicity Island 2 (SPI2), but that a functional SPI2 secretion system regulator (ssrA) was required for WT biofilm formation. We identified STM0341 as a gene of unknown function that was needed for WT biofilm growth. Genes involved in tryptophan (trp) biosynthesis and transport were up-regulated in the biofilm. Deletion of trpE led to a decrease in bacterial attachment and we show that this biofilm defect is restored by exogenous tryptophan or indole. Conclusion: Biofilm growth of S. Typhimurium causes distinct changes in gene and protein expression. Our results show that aromatic amino acids make an important contribution to biofilm formation, and reveal that SPI2 genes, required for virulence in host cells, show opposing patterns of expression to biofilm-specific genes in S. Typhimurium. Overnight cultures of SL1344 grown in CFA broth were standardized to achieve an initial concentration of 10^6 CFU ml-1 and injected into a stirring influent flask containing 5 L of pre-warmed (25C) sterile CFA medium. The inoculated influent was then pumped through silicon tubing (5 mm internal diameter, Samco Silicon Products Ltd.) at 60 ml h-1 using a peristaltic pump (Minipulse 3, Gilson). The bacteria were allowed to flow through the closed system and either attach to a vertical piece of silicon tubing (1 meter length, 16 mm internal diameter, Samco Silicon Products Ltd.) or flow out into a waste reservoir. The tubing was positioned vertically to collect biofilm cells adherent to the tubing and minimise collecting bacteria that had simply sedimented. Possible backflow of media or bacteria into the influent from the silicon tubing was eliminated using media breaks. Samples taken to determine the pH of the medium or bacterial cell counts were removed via a media port located near the effluent and influent vessel, respectively. Planktonic cells were removed after 72 h of growth from the influent vessel to avoid any contamination with biofilm cells. The entire system was kept at a constant temperature of 25C and biofilm cells were isolated after 72 h of growth. All planktonic and biofilm samples were isolated from the same experimental system and used for both RNA and protein isolation. For this study, four biological replicates were performed at four different dates (Jun25, Jul5, Jul16, Oct11; as indicated in the sample title). For the dual-colour microarray hybridisations, we used Salmonella genomic DNA as the comparator which also acted as the control for spot quality. Individual labelled cDNA samples (RNA) were hybridised up to 4 times (technical replicates).
2010-05-18 | E-GEOD-17246 | biostudies-arrayexpress
Project description:Long term-catheterization leads inevitably to a catheter-associated bacteriuria caused by multispecies bacterial biofilms growing on and in the catheters. The overall goal of the presented study was (I) to unravel bacterial community structure and function of such an uropathogenic biofilm and (II) to elucidate the interplay between bacterial virulence and the human immune system within the urine. To this end, a metaproteomics approach combined with in vitro proteomics analyses was employed to investigate both, the pro- and eukaryotic protein inventory. Our proteome analyses demonstrated that the biofilm of the investigated catheter is dominated by three bacterial species, i.e. Pseudomonas aeruginosa, Morganella morganii and Bacteroides sp., and identified iron limitation as one of the major challenges in the bladder environment. In vitro proteome analysis of P. aeruginosa and M. morganii isolated from the biofilm revealed that those opportunistic pathogens are able to overcome iron restriction via the production of siderophores and high expression of corresponding receptors. Notably, a comparison of in vivo and in vitro protein profiles of P. aeruginosa and M. morganii also indicated that the bacteria employ different strategies to adapt to the urinary tract. Whilst P. aeruginosa seems to express secreted and surface-exposed proteases to escape the human innate immune system and metabolizes amino acids, M. morganii is able to take up sugars and to degrade urea. Most interestingly, a comparison of urine protein profiles of three long-term catheterized patients and three healthy control persons demonstrated the elevated level of proteins associated to neutrophils, macrophages and complement system in the patient urine, which might point to a specific activation of the innate immune system in response to biofilm-associated urinary tract infections. We thus hypothesize that the often asymptomatic nature of CAUTI´s might be based on a fine-tuned balance between the expression of bacterial virulence factors and the human immune system. Long term-catheterization leads inevitably to a catheter-associated bacteriuria caused by multispecies bacterial biofilms growing on and in the catheters. The overall goal of the presented study was (I) to unravel bacterial community structure and function of such an uropathogenic biofilm and (II) to elucidate the interplay between bacterial virulence and the human immune system within the urine. To this end, a metaproteomics approach combined with in vitro proteomics analyses was employed to investigate both, the pro- and eukaryotic protein inventory. Our proteome analyses demonstrated that the biofilm of the investigated catheter is dominated by three bacterial species, i.e. Pseudomonas aeruginosa, Morganella morganii and Bacteroides sp., and identified iron limitation as one of the major challenges in the bladder environment. In vitro proteome analysis of P. aeruginosa and M. morganii isolated from the biofilm revealed that those opportunistic pathogens are able to overcome iron restriction via the production of siderophores and high expression of corresponding receptors. Notably, a comparison of in vivo and in vitro protein profiles of P. aeruginosa and M. morganii also indicated that the bacteria employ different strategies to adapt to the urinary tract. Whilst P. aeruginosa seems to express secreted and surface-exposed proteases to escape the human innate immune system and metabolizes amino acids, M. morganii is able to take up sugars and to degrade urea. Most interestingly, a comparison of urine protein profiles of three long-term catheterized patients and three healthy control persons demonstrated the elevated level of proteins associated to neutrophils, macrophages and complement system in the patient urine, which might point to a specific activation of the innate immune system in response to biofilm-associated urinary tract infections. We thus hypothesize that the often asymptomatic nature of CAUTI´s might be based on a fine-tuned balance between the expression of bacterial virulence factors and the human immune system.
2015-02-17 | PXD000164 | Pride
Project description:P. aeruginosa was cultured in a MultiScreen-Mesh plate, which has a filter at the bottom of the wells. The plate was immersed in either in medium alone (control) or in medium inoculated with a mixture of five bacterial strains commonly found in cystic fibrosis sputum (\"microbiome\"). The filter prevented physical contact between P. aeruginosa and the other bacteria, yet soluble products could migrate through the filter into the P. aeruginosa biofilm. P. aeruginosa was then allowed to form biofilms in the wells for 72h, then the biofilm was harvested and a fraction of the harvested cells were used for re-inoculations. This was repeated for 18 cycles for a total of 54 days.
2019-09-13 | E-MTAB-7331 | biostudies-arrayexpress
Project description:Bacteria growing in biofilms are physiologically heterogeneous, due in part to their adaptation to local environmental conditions. Here, we characterized the local transcriptional responses of Pseudomonas aeruginosa growing in biofilms by using microarray analysis of isolated biofilm subpopulations. The results demonstrated that cells at the top of the biofilms had high mRNA abundances for genes involved in general metabolic functions, while mRNAs for these housekeeping genes were low in cells at the bottom of the biofilms. Selective GFP labeling showed that cells at the top of the biofilm were actively dividing. However, the dividing cells had high mRNAs levels for genes regulated by the hypoxia induced regulator, Anr. Slow-growing cells deep in the biofilms had little expression of Anr-regulated genes and may have experienced long-termanoxia. Transcripts for ribosomal proteins were primarily associated with the metabolically active cell fraction, while ribosomal RNAs were abundant throughout the biofilms, indicating that ribosomes are stably maintained even in slowly growing cells. Consistent with these results was the identification of mRNAs for ribosome hibernation factors (rmf and PA4463) at the bottom of the biofilms. A P. aeruginosa M-bM-^HM-^Frmf strain had increased uptake of the membrane integrity stain, propidium iodide. Using selective GFP labeling and cell sorting, we showed that the dividing cells were more susceptible to tobramycin and ciprofloxacin than the dormant subpopulation. The results demonstrate that in thick P. aeruginosa biofilms, cells are physiologically distinct spatially, with cells deep in the biofilm in a viable but antibiotic-tolerant slow-growth state. 52-hour Pseudomonas aeruginosa TSA colony biofilms were cryoembedded, thin sectioned, and laser dissected (LCM) to obtain samples from the top and bottom 50 M-BM-5m of the biofilms. 9 sections per biofilm were pooled. RNA was extracted with the RNeasy Micro kit, Turbo DNase treated, poly(A) tailed, and amplified using the Quantitect WTA kit. After clean up, the resulting product was fragmented and end labeled before hybridization.
2012-05-02 | E-GEOD-34762 | biostudies-arrayexpress