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Arginase 1, an enzyme induced by Th2 cytokines, is a hallmark of alternatively activated macrophages and is responsible for the hydrolysis of L-arginine into ornithine, the building block for the production of polyamines. Upregulation of arginase 1 has been observed in a variety of diseases, but the mechanisms by which arginase contributes to pathology are(More)
OBJECTIVES YhiV (MdtF) is an resistance nodulation division (RND) type efflux pump in Escherichia coli with significant homology to AcrB but usually expressed at a low level in clinical isolates. When overexpressed the pump confers decreased susceptibility to a variety of substances including erythromycin and ethidium bromide (EtBr). We characterized two(More)
Demonstration of efflux of ethidium bromide (EtBr) has been made for over 30 bacterial species, usually by showing enhanced efflux in multidrug-resistant strains that was then abolished by inactivating efflux pumps. Here we present a relatively simple automated method that employs EtBr as an efflux pump substrate for the demonstration of intrinsic efflux(More)
The Escherichia coli multidrug efflux pump protein AcrB has recently been cocrystallized with various substrates, suggesting that there is a phenylalanine-rich binding site around F178 and F615. We found that F610A was the point mutation that had the most significant impact on substrate MICs, while other targeted mutations, including conversion of(More)
Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs) in innate defense against Nocardia, the(More)
The Escherichia coli AcrB efflux pump is a resistance-nodulation-division (RND) pump that recognizes many unrelated compounds (9, 10). AcrB forms a complex with AcrA and TolC and is the single most important contributor to multidrug resistance in E. coli. Crystallographic models suggest that AcrB forms an asymmetric trimer in which each protomer corresponds(More)
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