title: Identification of three novel ostricacins: an update on the phylogenetic perspective of beta-defensins.
abstract: Three new beta-defensins, ostricacins-2, 3 and 4 (Osp-2, 3 and 4), have been successfully purified and characterised from ostrich heterophils in addition to ostricacin-1 (Osp-1). These peptides are composed of 36-42 amino acids with a molecular weight range of 4.70-4.98 kDa. In vitro, Osp-1, 3 and 4 were active against Escherichia coli O157:H7 and Staphylococcus aureus 1056 MRSA, whilst Osp-2 was active against bacterial strains plus the yeast Candida albicans 3153A. Minimal inhibitory concentrations of the three ostricacins ranged from 0.96 microg/mL to 12.03 microg/mL. Comparison with the known beta-defensins from mammalian and other avian species revealed that the four ostricacins shared eight conserved residues (six cysteines and two glycines), identified as the 'beta-defensin core motif'. Comparisons of the sequence also indicated that beta-defensins could have originated from a common beta-defensin-like ancestor that occurred before avian and mammalian lines diverged.
authors.affiliation: Biotechnology Group, Institute of Technology and Engineering, Massey University, Private Bag 11-222, Palmerston North 5301, New Zealand.
authors.forename: Haryadi
authors.initials: H
authors.lastname: Sugiarto
authors.forename: Pak-Lam
authors.initials: PL
authors.lastname: Yu
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D020310:Struthioniformes; D023083:beta-Defensins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000494:pharmacology*
chemical_list: D023083:beta-Defensins