Project description:In this study, we identified the O-glycosylation sites in recombinant Clostridium botulinum flagellin (CbFla) and Geobacillus kaustophilus flagellins, GkFlaA1 and GkFlaA2, expressed from the E. coli strains, EV136 and EV240 (K1:K12 strains engineered by Prof. Eric Vimr’s group to accumulate CMP-sialic acid in the cytosol), EV36 (wildtype K1:K12 strain), and BL21(DE3) (laboratory strain used for protein expression using T7 RNA polymerase). The recombinant flagellins were expressed with or without co-expression of motility associated factor (Maf) (flagellin nonulosonic acid glycosyltransferase) in these strains, purified and subjected to MS/MS analysis at Taplin Biological Mass Spectrometry facility.
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:We have performed ChIP-Seq experiment for the global regulators, CRP and Fis in early and mid exponential growth phases respectively in Escherichia coli K12 MG1655. The dataset contains the genome wide binding patterns of Fis and CRP in the wildtype and the mutant strains
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. Escherichia coli O157:H7 strains were grown in the lettuce rhizosphere for three days. Transcriptional profiling of E. coli was compared between cells grown with and without rhizosphere . Three biological replicates of each treatment were prepared, and six microarray slides were used.
Project description:An assortment of genetically engineered Escherichia coli strains of the rewired gene regulation were used to study whether the cells could adapt to the environmental changes without the evolved gene regulatory machinaries. These E. coli strains had a synthetic gene circuit comprising a rewried gene that natively located within the His opeon. The cells growing under histidine supplied or depleted conditions were subjected to the macrioarray analysis. Multilevel analyses were performed to evaluate the global reorganization of gene expression in response to histidine depletion. A common pattern in transcriptome was observed in the adpative cells, indicating a survival strategy of "stochastic adaptation with regular transcriptome reorganization". The genetically engineered strains of rewired genes and the control strain of the native gene regulation were grown in the presence and absence of histidine, and the cells within the exponetially growing phase were collected for the microarray analysis. Temproal changes in response to histidine depletion were also investigated. Every 3 biological replications for each condition were performed. Total 90 array assays were reported here.
Project description:We generated four strains of Escherichia coli K12 MG1655 with distinct proton motive force generation potential and performed the adaptive laboratory evolution of these strains to study how the system adapts to the loss of alternate electron transfer pathways of the Electron Transport System. RNA-Seq was performed to examine the underlying transcriptional rewiring.
Project description:The E. coli Genechip antisense genome array was used to study the differential gene expression profile of E. coli K12 ydgG mutant compared to its isogenic wild type in a mature biofilm. Keywords: E. coli K12 antisense chip
Project description:The gene expression of glasswool biofilm cells in E. coli yjgI mutant vs. E. coli wild type strain in LB. Strains: E. coli K12 BW25113 wild type, yjgI mutant Medium: LB Biofilm grown on glass wool Time: 15 h Cell type: biofilm
Project description:In this study, we identified the O-glycosylation sites in deletion constructs of recombinant Clostridium botulinum flagellin (CbFla) expressed from the E. coli strain, EV136 (K1:K12 strains engineered by Prof. Eric Vimr’s group to accumulate CMP-sialic acid in the cytosol). The recombinant flagellins were expressed with or without co-expression of motility associated factor (Maf) (flagellin nonulosonic acid glycosyltransferase) in these strains, purified and subjected to MS/MS analysis at Taplin Biological Mass Spectrometry facility. We also studied the O-glycosylation of recombinant Clostridium botulinum flagellin (CbFla) co-expressed with Geobacillus kaustophilus Maf. We also studied the O-glycosylation of flagellin chimeras made by grafting mini-flagellin sequences on to an unrelated protein with an F-type lectin domain from Streptosporangium roseum SrNaFLD.
Project description:An assortment of genetically engineered Escherichia coli strains of the rewired gene regulation were used to study whether the cells could adapt to the environmental changes without the evolved gene regulatory machinaries. These E. coli strains had a synthetic gene circuit comprising a rewried gene that natively located within the His opeon. The cells growing under histidine supplied or depleted conditions were subjected to the macrioarray analysis. Multilevel analyses were performed to evaluate the global reorganization of gene expression in response to histidine depletion. A common pattern in transcriptome was observed in the adpative cells, indicating a survival strategy of "stochastic adaptation with regular transcriptome reorganization".