The amount of acrB, marA, and soxS mRNA was determined in 36 fluoroquinolone-resistant E. coli from humans and animals, 27 of which displayed a multiple-resistance phenotype. acrB mRNA was elevated in 11 of 36 strains. A mutation at codon 45 (Arg-->Cys) in acrR was found in 6 of these 11 strains. Ten of the 36 isolates appeared to overexpress soxS, and five appeared to overexpress marA. A numbe...

The MarR (multiple antibiotic resistance regulator) family of prokaryotic transcriptional regulators includes proteins critical for control of virulence factor production, bacterial response to antibiotic and oxidative stresses and catabolism of environmental aromatic compounds. Recognition of the adaptive cellular responses mediated by MarR homologs, and the clinical isolation of antibiotic-re...

Bacteria and archaea encode members of the large multiple antibiotic resistance regulator (MarR) family of transcriptional regulators. Generally, MarR homologs regulate activity of genes involved in antibiotic resistance, stress responses, virulence or catabolism of aromatic compounds. They constitute a diverse group of transcriptional regulators that includes both repressors and activators, an...

Biologists rely on keyword-based search engines to retrieve superficially relevant papers, from which they must filter out the irrelevant information manually. Question answering (QA) systems can offer more efficient and user-friendly ways of retrieving such information. Two contributions are provided in this paper. First, a factoid QA system is developed to employ a named entity recognition mo...

Earlier13,18,19, the biologically plausible active vision ,model for Multiresolutional Attentional Representation and Recognition (MARR) has been developed. The model is based on the scanpath theory of Noton and Stark17and provides invariant recognition of gray-level images. In the present paper, the algorithm of automatic image viewing trajectory formation in the MARR model, the results of psy...

To many, the poster child for David Marr's famous three levels of scientific inquiry is reinforcement learning-a computational theory of reward optimization, which readily prescribes algorithmic solutions that evidence striking resemblance to signals found in the brain, suggesting a straightforward neural implementation. Here we review questions that remain open at each level of analysis, concl...

Figure 1. Representative MarR homologs and their mode of gene regulation. (A) Structure of MTH313 (3BPX), a MarR homolog of unknown function from Methanobacterium thermoautotrophicum, in complex with the ligand salicylate (shown in magenta). One monomer is shown in gray, the other is colored from amino to carboxyl terminus (blue to red). Note the asymmetrical ligand binding; only ligand binding...

All living organisms have molecular systems that enable them to resist a variety of toxic substances and environmental stresses. Proteins belonging to the Multiple antibiotic resistance Regulators (MarR) family reportedly regulate the expression of proteins conferring resistance to multiple antibiotics, organic solvents, household disinfectants, oxidative stress agents and pathogenic factors (A...

Resistance to multiple antibiotics and certain oxidative stress compounds was conferred by three independently selected mutations (marR1, soxQ1, and cfxB1) that mapped to 34 min on the Escherichia coli chromosome. Mutations at this locus can activate the marRAB operon, in which marR encodes a putative repressor of mar transcription and marA encodes a putative transcriptional activator of defens...