Dataset Information

Adapted tolerance to Benzalkonium chloride in E. coli K12

ABSTRACT: Benzalkonium chloride (BC) is a commonly used disinfectant and preservative. This study describes changes in expression level on the transcriptomic and proteomic level for Escherichia coli K12 gradually adapted to a tolerance level towards BC of 7-8 times the initial MIC. Results from DNA arrays and two-dimensional (2-DE) gel electrophoresis for global gene and protein expression studies were confirmed by real time quantitative PCR. Peptide mass fingerprinting by MALDI-TOF MS was used to identify differentially expressed proteins. Changes in expression level in adapted cells were shown for porins, drug transporters, glycolytic enzymes, ribosomal subunits and several genes and proteins involved in protection against oxidative stress and antibiotics. Adapted strains showed increased tolerance to several antibiotics. In conclusion, E. coli K12 adapted to higher tolerance to BC, acquired several general resistance mechanisms including responses normally related to the multiple antibiotic resistance (Mar) regulon and protection against oxidative stress. The results revealed that BC treatment might result in superoxide stress in E. coli. Keywords: Study of resistance mechanism

ORGANISM(S): Escherichia coli

PROVIDER: GSE6712 | GEO | 2007/05/23

SECONDARY ACCESSION(S): PRJNA99035

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:E. coli growing in continuous culture under continuous UVA irradiation exhibits growth inhibition with a subsequent adaptation to the stress. Transcriptome analysis was performed during transient growth inhibition and in the UVA light-adapted growth state. The results indicate that UVA light induces stringent response and an additional response that includes the upregulation of the synthesis of valine, isoleucine, leucine, phenylalanine, histidine and glutamate. The induction of several SOS response-genes strongly points to DNA damage as a result of UVA exposure. The involvement of oxidative stress was observed with the induction of ahpCF. Taken together it supports the hypothesis of the production of reactive oxygen species by UVA light. In the UVA-adapted cell population strong repression of the acid tolerance response was found. We identified the enzyme chorismate mutase as a possible chromophore for UVA light-inactivation and found strong repression of the pyrBI operon and the gene mgtA encoding for an ATP dependent Mg2+ transporter. Furthermore, our results indicate that the role of RpoS may not be as important in the adaptation of E. coli to UVA light as it was implicated by previous results with starved cells, but that RpoS might be of crucial importance for the resistance under transient light exposure. Slide microarrays were purchased from MWG-Biotech AG (Ebersberg, Germany). The MWG E. coli Array contains 4,288 gene specific oligonucleotide probes representing the complete E. coli K12 genome. Microarray slides were scanned using the Affymetrix 428TM Array Scanner (High Wycombe, UK). Spot intensities and corresponding background signals were quantified with the Affymetrix JaguarTM software version 2.0. Further data analysis was performed with the program GeneSpring from Silicon Genetics (Redwood City, CA, USA). Induction factors (IF) were calculated from the Cy3 and Cy5 signal intensities of the spot. Spots with signal intensity below a value of 50 were excluded from the analysis and the minimal induction factor was set to 0.01. The normalization was performed with the 50th percentile distribution of remaining spots after background correction. The mean value of the IF of a specific gene was calculated from three replicates. Biological experiments were carried out three times, which provided three biological repeats. Dye swapping was performed for one replicate and did not alter the result.

Project description:Leafy green vegetables, such as lettuce, have been increasingly implicated in outbreaks of foodborne illnesses due to contamination by Escherichia coli O157:H7. While E. coli can survive in soils, colonize plants, and survive on produce, very little is known about the interaction of E. coli with the roots of growing lettuce plants. In these studies, a combination of microarray analyses and surface enhanced Raman spectroscopy (SERS) were used to gain a comprehensive understanding of bacterial genes involved in the colonization and growth of E. coli O157:H7 on lettuce roots and compared to E. coli K12 using a hydroponic system (HS) which we have reported in the previous studies. Using microarray, after three days of interaction with lettuce roots, 94 and 109 genes of E. coli O157:H7 were significantly up-regulated and down-regulated at least 1.5 fold, respectively. Only 8 genes were also found in the E. coli K12 up-regulated genes. No genes were found in the down-regulated genes clusters between those two strains. For E. coli O157:H7, forty out of the 94 up-regulated genes (43%) were involved in protein synthesis and were highly repressed compared to 40 out of 193 (23%) E. coli K12 up-regulated genes associated with protein synthesis. The wildtype of E.coli O157:H7 colonized two log CFU per root less compared to E. coli K12. Genes involved in biofilm modulation (bhsA and ybiM) were significantly up-regulated in E. coli O157:H7 and curli production (crl and csgA) were found important for E. coli K12 to attach to lettuce roots in the previous studies. BhsA mutant of E. coli O157:H7 was impaired in the colonization of lettuce roots. The SERS spectra of E. coli K12 and O157 controls (cells without interacting with roots) were very similar. The spectra of E. coli K12 and O157 exposed to the hydroponic system (HS) showed some differences in the nucleic acid, protein, and lipid regions compared with controls. The spectra of E. coli K12 HS cells exhibited significant differences compared to spectra from E. coli O157 HS cells in the RNA and protein regions. The overall band intensity of amide regions declined for E. coli O157 HS cells, while it increased for E. coli K12 HS cells. The intensity of the RNA bands of E. coli K12 HS cells were also found much higher than those of E. coli O157 HS cells. These findings were in agreement to our Microarray data. Our microarray and SERS data showed that E. coli K12 and O157:H7 behavior dramatically differently in colonizing on lettuce roots. Compared to K12, E. coli O157:H7 colonized less efficiently on lettuce roots.

Dataset Information

Adapted tolerance to Benzalkonium chloride in E. coli K12

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure