1. A proposed nomenclature for antimicrobial peptides from frogs of the genus Leptodactylus
J Michael Conlon Peptides. 2008 Sep;29(9):1631-2. doi: 10.1016/j.peptides.2008.04.016. Epub 2008 May 4.
It is proposed that the current nomenclature by which individual antimicrobial peptides from the skins of frogs belonging to the genus Leptodactylus are named from the species of frog from which they were isolated should be replaced by one that emphasizes the fact that these peptides are evolutionarily related. As the ocellatins from Leptodactylus ocellatus were the first such peptides to be characterized, it is suggested that all orthologous peptides should be described as "ocellatins". Consistent with accepted terminology for other families of antimicrobial peptides, the upper case initial letter of the species is used to indicate their origin and isoforms are designated by numbers. When two species begin with the same initial letter, a second distinguishing letter shall be employed. Thus, the terms ocellatin-1, -2, -3, and -4 are retained for the parent peptides. Fallaxin is replaced by ocellatin-F1, pentadactylin by ocellatin-P1, laticeptin by ocellatin-L1, syphaxin by ocellatin-S1, and the paralogs from L. validus are termed ocellatin-V1, -V2, and -V3.
2. Antimicrobial peptide from the skin secretion of the frog Leptodactylus syphax
Flávio S Dourado, José Roberto S A Leite, Luciano P Silva, Jorge A T Melo, Carlos Bloch Jr, Elisabeth F Schwartz Toxicon. 2007 Sep 15;50(4):572-80. doi: 10.1016/j.toxicon.2007.04.027. Epub 2007 Jun 7.
Antimicrobial peptides are considered part of the innate immune system of the majority of living organisms. Most of these molecules are small, cationic and show amphiphilic nature. The skin secretions of Leptodactylus syphax were extracted by mild electrical stimulation and its semipreparative reverse-phase chromatography was resolved in more than 40 fractions. Among these fractions, an antimicrobial peptide was isolated and its amino acid sequence determined by de novo sequencing. Six other truncated forms were characterized in skin secretion. The longest one (25 amino acid residues), named syphaxin (SPX), is amidated at the C-terminal, and shares strong sequence similarity with antimicrobial peptides found in the skin secretion of leptodactylid frogs. Two of the truncated peptides (SPX(1-22) and SPX(1-16)) were tested against Escherichia coli and Staphylococcus aureus, showing low minimal inhibitory concentration (MIC) and no significant toxicity towards blood cells, including both leukocytes and erythrocytes, based on their direct incubation in whole blood at the highest MIC concentration (64 microg/mL).
