Escherichia coli
Genetics and Molecular BiologyInverted Regulation of Multidrug Efflux Pumps, Acid Resistance, and Porins in Benzoate-Evolved Escherichia coli K-12Benzoic acid is a common food preservative, and salicylic acid (2-hydroxybenzoic acid) is the active form of aspirin. At high concentrations, benzoic acid conducts a proton across the membrane, depleting the proton motive force. In the absence of antibiotics, benzoate exposure selects against proton-driven multidrug efflux pumps and upregulates porins that admit fermentable substrates but that also allow the entry of antibiotics. Thus,...
BiotechnologyChemical and Metabolic Controls on Dihydroxyacetone Metabolism Lead to Suboptimal Growth of Escherichia coliDHA is an attractive triose molecule with a wide range of applications, notably in cosmetics and the food and pharmaceutical industries. DHA is found in many species, from microorganisms to humans, and can be used by Escherichia coli as a growth substrate. However, knowledge about the mechanisms and regulation of this process is currently lacking, motivating our...
BiotechnologyPosttranslational Targeting of a Recombinant Protein Promotes Its Efficient Secretion into the Escherichia coli PeriplasmThe bacterium Escherichia coli is widely used to produce recombinant proteins. To fold properly, many recombinant proteins have to be targeted to the E. coli periplasm, but so far the impact of the targeting pathway of a recombinant protein to the periplasm has not been extensively investigated....
Genetics and Molecular BiologyMethionine Limitation Impairs Pathogen Expansion and Biofilm Formation CapacityNew antibiotics that attack novel targets are needed to circumvent widespread resistance to conventional drugs. Bacterial anabolic pathways, such as the enzymes for biosynthesis of the essential amino acid methionine, have been proposed as potential targets. However, the eligibility of enzymes in these pathways as drug targets is unclear because metabolites might be acquired from the environment to overcome inhibition. We investigated...
Food MicrobiologyLongitudinal Study of Shiga Toxin-Producing Escherichia coli and Campylobacter jejuni on Finnish Dairy Farms and in Raw MilkThe increased popularity of raw milk consumption has created demand for relaxing legislation, despite the risk of contamination by pathogenic bacteria, notably STEC and C. jejuni. However, the epidemiology of these milk-borne pathogens on the herd level is still poorly understood, and data are lacking on the frequency of milk contamination on farms with cattle...
Public and Environmental Health MicrobiologyHost Range-Associated Clustering Based on Multilocus Variable-Number Tandem-Repeat Analysis, Phylotypes, and Virulence Genes of Atypical Enteropathogenic Escherichia coli StrainsAtypical enteropathogenic Escherichia coli (aEPEC) is a diarrheagenic type of E. coli, as it possesses the intimin gene (eae) for attachment and effacement on epithelium. Since aEPEC is ubiquitous even in developed countries, we previously used molecular epidemiological methods to...
BiotechnologyBioprospecting of Native Efflux Pumps To Enhance Furfural Tolerance in Ethanologenic Escherichia coliLignocellulosic biomass, especially agricultural residues, represents an important potential feedstock for microbial production of renewable fuels and chemicals. During the deconstruction of hemicellulose by thermochemical processes, side products that inhibit cell growth and production, such as furan aldehydes, are generated, limiting cost-effective lignocellulose conversion. Here, we developed a new approach to increase cellular...
MethodsRapid and Simple Universal Escherichia coli Genotyping Method Based on Multiple-Locus Variable-Number Tandem-Repeat Analysis Using Single-Tube Multiplex PCR and Standard Gel ElectrophoresisFast typing methods that can easily and accurately distinguish clonal groups and unrelated isolates are of particular interest for microbiologists confronted with outbreaks or performing epidemiological studies. Highly discriminatory universal methods, like PFGE, optical mapping, or WGS, are expensive and/or time-consuming. MLST is useful for phylogeny but is less discriminatory and requires sequencing facilities. PCR methods, which are...
Public and Environmental Health Microbiology | SpotlightSurvival of Escherichia coli in Manure-Amended Soils Is Affected by Spatiotemporal, Agricultural, and Weather Factors in the Mid-Atlantic United StatesCurrent language in the Food Safety Modernization Act Produce Safety Rule states no objection to a 90- or 120-day interval between application of untreated BSAAO and harvest of crops to minimize transfer of pathogens to produce intended for human consumption with the intent to limit potential cases of foodborne illness. This regional multiple season, multiple location field trial determined survival durations of...
Evolutionary and Genomic Microbiology | SpotlightResistance Gene Carriage Predicts Growth of Natural and Clinical Escherichia coli Isolates in the Absence of AntibioticsManaging the spread of antibiotic resistance in bacterial pathogens is a major challenge for global public health. Central to this challenge is understanding whether resistance is linked to impaired bacterial growth in the absence of antibiotics, because this determines whether resistance declines when bacteria are no longer exposed to antibiotics. We studied 92 isolates of the key bacterial pathogen...