Showing papers on "Antimicrobial peptides published in 1985"

Primary structures of three human neutrophil defensins.

Abstract: The primary structures of three human neutrophil antimicrobial peptides (HNP) were determined. The peptides, HNP-1, HNP-2, and HNP-3, which we have termed defensins, were rich in cystine, arginine, and aromatic residues, but were devoid of free sulfhydryl groups and carbohydrate moieties. They were 29-30 residues in length and identical in sequence in all but their amino terminal residues. The defensins were homologous in sequence to peptides of similar size and biological activity previously purified from rabbit polymorphonuclear leukocytes, but unrelated to other neutrophil proteins of known sequence. 11 amino acid residues of the human defensins, including all six cysteinyl residues, were invariantly conserved in the six rabbit members of this multigene peptide family. That similarly structured antimicrobial peptides are present in both rabbit and human leukocytes supports their purported role as cidal agents in phagocyte-mediated host defense.

Activity of rabbit leukocyte peptides against Candida albicans.

Abstract: Six related cysteine-rich, low-molecular-weight peptides were purified from rabbit peritoneal granulocytes and tested in vitro for fungicidal activity against Candida albicans. Two peptides (NP-1 and NP-2) were highly effective, one (NP-3a) was moderately active, and three (NP-3b greater than NP-4 much greater than NP-5) had substantially less potency. There was a general, but imperfect, correlation between the candidacidal potency of each peptide and its net cationic charge. Candidacidal activity by NP-1 was concentration and time dependent and occurred rapidly under optimal low-ionic-strength conditions. It was inhibited by increasing either the ionic strength or Ca2+ concentration of the incubation mixtures, but was relatively unaffected by Mg2+. Candidacidal activity was independent of H+ concentrations between pH 5 and 8, but decreased below pH 5. Candidacidal activity was temperature sensitive and was virtually abolished when NP-1 was incubated with C. albicans at 0 degrees C. Cysteine-rich antimicrobial peptides such as NP-1 and NP-2 may equip leukocytes to deal with infections caused by C. albicans and other fungi that are susceptible to their microbicidal effects.