Project description: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
Project description:Transcriptional profiling of E. coli cells comparing control harboring the empty vector pRadGro (Ec-pR) with E. coli expressing the Deinococcus radiodurans response regulator DR1558 (Ec-1558) Expression of DR1558 conferred to multi-stress tolerance to E. coli. Cells grown to exponential phase (OD600 = 0.8) were harvested. Biological replicates, 3. Escherchia coli K12 oligonucleotide 3X15 K microarray (MYcroarray Inc. USA)
Project description:In the present study we have determined the global gene expression and biomolecular composition in an Escherichia coli model strain exposed to ten adverse conditions (sodium chloride, ethanol, glycerol, two acids (hydrochloric acid and acetic acid), sodium hydroxide, heat (46°C) and cold (15°C) as well as ethidium bromide and the disinfectant benzalkonium chloride). The large variation in responses and few common genes illustrates the adaptation potential of E. coli and its ability to survive and colonize a wide range of environments. Keywords: gene expression study, stress response
Project description:The goal of this Tn-Seq study was to determine important determinants of Acinetobacter baumannii tolerance of sub-MIC concentrations of benzalkonium chloride. This Tn-seq data was then utilized to aide in the determination of the sub-MIC mechanism of action for benzalkonium chloride.
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.
Project description:Proteomics analysis in Escherichia coli K12 (E. coli K12) at DMP concentrations of 0 mg·kg-1 (CK) and 80 mg·kg-1 (DMP) revealed the toxicity of DMP
Project description:DNA microarrays were conducted on E. coli K12 cells stressed with 10 μM in N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN). Overall, 260 genes varied in expression, 114 up-regulated and 146 down-regulated by Zn deprivation Keywords: TPEN stress