Norris E Allen

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Most bacteria synthesize muramyl-pentapeptide peptidoglycan precursors ending with a D-alanyl residue (e.g., UDP-N-acetylmuramyl-L-Ala-gamma-D-Glu-L-Lys-D-Ala-D-Ala). However, it was recently demonstrated that other types of precursors, notably D-lactate-ending molecules, could be synthesized by several lactic acid bacteria. This particular feature leads to(More)
A novel low-molecular weight inhibitor of an aminoglycoside-inactivating enzyme, initially isolated from fermentation broths of Streptomyces neyagawaensis, was determined to be 7-hydroxytropolone. Its structure was confirmed by synthesis. In vitro synergy was demonstrated between 7-hydroxytropolone and certain aminoglycosides against bacteria which were(More)
A plasmid conferring resistance to the aminocyclitol antibiotic hygromycin B was isolated from Escherichia coli. The gene conferring resistance to this drug was cloned in pBR322, and the gene was localized to a fragment of ca. 1,510 base pairs. Resistance to hygromycin B is determined by an aminocyclitol phosphotransferase that modifies hygromycin B and(More)
Bacitracin and other antibiotics that inhibit late stages in peptidoglycan biosynthesis induce vancomycin resistance in a high-level, inducibly vancomycin-resistant strain of Enterococcus faecium. Exposure to bacitracin led to synthesis of the lactate-containing UDP-MurNAc-pentadepsipeptide precursor required for vancomycin resistance. These findings(More)
LY146032, a cyclic lipopeptide antibiotic, is an inhibitor of cell wall peptidoglycan biosynthesis in gram-positive bacteria. Although LY146032 at relatively high concentrations inhibited the in vitro polymerization of UDP-linked sugar precursors, inhibition of cell wall formation in intact Staphylococcus aureus and Bacillus megaterium cells did not lead to(More)
Staphylococcus aureus small-colony variants (SCVs) have been implicated in chronic and persistent infections. Bovine mastitis induced by S. aureus is an example of an infection difficult to eradicate by conventional antimicrobial therapies. In this study, the ability to colonize mouse mammary glands and persist under antibiotic treatment was assessed for S.(More)
Novel bacterial resistance genes were cloned and expressed as dominant selection markers in mammalian cells. Escherichia coli genes coding for resistance to the aminocyclitol antibiotics hygromycin B (Hm) and G418 were cloned into the eukaryotic expression plasmid pSV5GPT [Mulligan and Berg, Proc. Natl. Acad. Sci. USA 78 (1981) 2072-2076]. Mouse cells(More)
In the presence of bacitracin, vancomycin-resistant Enterococcus faecium (vanA phenotype) accumulate UDP-N-acetylmuramyl(UDP-Mur-NAc)-tetrapeptide and a UDP-MurNAc-depsipentapeptide containing lactate substituted for the carboxy-terminal-D-alanine residue. In an in vitro peptidoglycan polymerization assay, the modified precursors function and confer(More)
Capillary electrophoretic methods were used to examine dimerization and estimate dimerization constants (Kdim) for the glycopeptide antibiotics vancomycin, ristocetin A, and LY264826 (A82846B). The Kdim for LY264826 was 60- and 200-fold higher than the Kdim for ristocetin A and vancomycin, respectively. Dimerization of vancomycin measured in the presence of(More)