Dataset Information

Comparative metabolomics and transcriptomics revealed multiple pathways associated with polymyxin killing in Pseudomonas aeruginosa

ABSTRACT: Polymyxins are the last-line antibiotics against multidrug-resistant Pseudomonas aeruginosa however, resistance to polymyxins has been increasingly reported. Therefore, understanding the mechanisms of polymyxin activity and resistance is crucial for preserving their clinical usefulness. This study employed comparative metabolomics and transcriptomics to investigate the responses of polymyxin-susceptible PAK (polymyxin B MIC 1 mg/l) and its polymyxin-resistant pmrB mutant PAKpmrB6 (MIC 16 mg/l) to polymyxin B (4, 8, and 128 mg/l) at 1, 4, and 24h. Our results revealed that polymyxin B at 4 mg/l induced different metabolic and transcriptomic responses between polymyxin-susceptible and -resistant P. aeruginosa. In PAK, polymyxin B significantly activated PmrAB and the mediated arn operon, leading to increased 4-amino-4-deoxy-L-arabinose (L-Ara4N) synthesis and the addition to lipid A. On the contrary, polymyxin B did not increase lipid A modification in PAKpmrB6. Moreover, the syntheses of lipopolysaccharide and peptidoglycan were significantly decreased in PAK, but increased in PAKpmrB6 due to polymyxin B treatment. In addition, 4 mg/l polymyxin B significantly perturbed phospholipid and fatty acid levels and induced oxidative stress in PAK, but not in PAKpmrB6. Notably, the increased trehalose-6-phosphate levels indicate that polymyxin B potentially caused osmotic imbalance in both strains. Furthermore, 8 and 128 mg/l polymyxin B significantly elevated lipoamino acid levels and decreased phospholipid levels, but without dramatic changes in lipid A modification in both wildtype and mutant strains. Overall, this systems study is the first to elucidate the complex and dynamic interactions of multiple cellular pathways associated with polymyxin mode of action against P. aeruginosa.

INSTRUMENT(S): Liquid Chromatography MS - Alternating (LC-MS (Alternating))

SUBMITTER: Mei-Ling Han

PROVIDER: MTBLS751 | MetaboLights | 2018-11-14

REPOSITORIES: MetaboLights

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	MTBLS751	Other
	FILES	Other
	a_MTBLS751_study1_metabolite_profiling_mass_spectrometry.txt	Txt
	a_MTBLS751_study2_metabolite_profiling_mass_spectrometry.txt	Txt
	i_Investigation.txt	Txt

Items per page:

1 - 5 of 10

Similar Datasets

Project description:Polymyxin B (PB) is introduced into the clinic as the last-line therapy against carbapenem-resistant Klebsiella pneumoniae (CRKP). Unfortunately, increased resistance to PB in Klebsiella pneumoniae (K. pneumoniae) has threatened global health. Resistance of K. pneumoniae to PB was induced by passaging in serial concentrations of PB and determined by microbroth dilution method. Growth characteristics of induced strains including growth curve, reversibility of resistance, and biofilm formation (crystal violet staining method) were measured. This study employed TMT-labeled quantitative proteomics and LC-MS/MS metabolomics analysis to investigate the key biological processes associated with PB resistance in K. pneumoniae. A total of 315 differentially expressed proteins (DEPs) were identified, of which 133 were upregulated and 182 were downregulated in the PB-resistant K. pneumoniae. KEGG enrichment analysis revealed that the DEPs were mainly involved in ATP-binding cassette (ABC) transporters and cationic antimicrobial peptide (CAMP) resistance. Proteins related to central carbon metabolism were inhibited in the PB-resistant K. pneumoniae, but proteins mediating LPS modification were activated. Transcriptional levels of CAMP resistance-related proteins were significantly different between PB-susceptible and -resistant K. pneumoniae. PB treatment led to an increase in reactive oxygen species (ROS) levels of K. pneumoniae. Metabolomics data demonstrated that 23 metabolites were significantly upregulated in PB-resistant K. pneumoniae and 5 were downregulated. The differential metabolites were mainly lipids, including glycerophospholipids, sphingolipids, and fatty acids. Exposure to PB resulted in increased level of phospholipid transport gene mlaF in K. pneumoniae. Our study suggested that membrane remodeling and inhibited central carbon metabolism are conducive to the development of PB resistance in K. pneumoniae.

Project description:Fusarium verticillioides is a detrimental fungus that can contaminate maize grains with mycotoxins that are harmful to human and animal health. Breeding and growing resistant genotypes is one alternative to reduce contamination and subsequent production of mycotoxins by this fungus. However, little is known about the resistant mechanism relevant to breeding in this pathosystem. Therefore, our aim was to identify genes and metabolites that may be related to Fusarium ear rot resistance using resistant and susceptible maize inbreds. Kernels of the resistant inbred showed significantly reduced disease severity, and reduced levels of total fumonisin and ergosterol content compared with the susceptible one. Gene expression data were obtained from microarray hybridizations using F. verticillioides inoculated and non inoculated maize kernels. Differentially expressed sequences were identified and classified into 36 functional categories. Most of the differentially expressed genes were assigned to the categories “protein, RNA, DNA, stress, transport, signaling and cell metabolism”. These genes encode for PR proteins, detoxification and primary metabolism enzymes. Fungal inoculation did not produce considerable changes in gene expression and metabolites in the resistant L4637 inbred, probably due to a preformed or constitutive resistance mechanism. Defense-related genes were induced or repressed in kernels of the susceptible inbred L4674, responding specifically to the pathogen infection. The qRT-PCR in infected silks showed that glucanase, lipid transfer, xylanase inhibitor, PR1 and 26S proteosome transcripts had higher expression ratios in the susceptible line compared to the resistant one in response to fungal infection. Through this study, a global view of differential genes expressed and metabolites concentration during resistance and susceptibility to F. verticillioides inoculation has been obtained, giving additional information about the mechanisms and pathways conferring resistance to this important disease in maize. Global view of differential genes expressed during resistance and susceptibility to F. verticillioides inoculation. Two maize inbred lines : one resistant (L4637) and one susceptible (L4674) to F. verticillioides infection. Two-condition experiment, Inoculated (I) vs. non-inoculated (NI) lines. Biological replicates: 3 . One replicate per array.

Dataset Information

Comparative metabolomics and transcriptomics revealed multiple pathways associated with polymyxin killing in Pseudomonas aeruginosa

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets