Publications by authors named "Barbara M Spathelf"

The structures of two major tyrocidines, antibiotic peptides from Bacillus aneurinolyticus, in an aqueous environment were studied using nuclear magnetic resonance spectroscopy, restrained molecular dynamics (MD), circular dichroism, and mass spectrometry. TrcA and TrcC formed β-structures in an aqueous environment. Hydrophobic and hydrophilic residues were not totally separated into nonpolar and polar faces of the peptides, indicating that tyrocidines have low amphipathicity.

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A group of non-ribosomally produced antimicrobial peptides, the tyrocidines from the tyrothricin complex, have potential as antimicrobial agents in both medicine and industry. Previous work by our group illustrated that the more polar tyrocidines rich in Trp residues in their structure were more active toward Gram-positive bacteria, while the more non-polar tyrocidines rich in Phe residues had greater activity toward Plasmodium falciparum, one of the major causative pathogens of malaria in humans. Our group also found that the tyrocidines have pronounced antifungal activity, dictated by the primary sequence of the tyrocidine.

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Six major tyrocidines, purified from the antibiotic tyrothricin complex produced by Bacillus aneurinolyticus, showed significant lytic and growth inhibitory activity towards the gram+ bacteria, Micrococcus luteus and Listeria monocytogenes, but not against the gram- bacterium, Escherichia coli. The isolated natural tyrocidines were in particular more active against the leucocin A (antimicrobial peptide) resistant strain, L. monocytogenes B73-MR1, than the sensitive L.

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