Orthologs of magainin, PGLa, procaerulein-derived, and proxenopsin-derived peptides from skin secretions of the octoploid frog Xenopus amieti (Pipidae).

The Volcano clawed frog Xenopus amieti Kobel, du Pasquier, Fischberg, and Gloor, 1980, with a chromosome number of 2n=72, is believed to have undergone two rounds of genome duplication since evolving from a diploid ancestor. Nine peptides with differential antimicrobial activity against Escherichia coli and Staphylococcus aureus were isolated from norepinephrine-stimulated skin secretions of X. amieti that showed structural similarity to peptides previously isolated from the tetraploid frog X.

Antimicrobial peptides from the skin secretions of the South-East Asian frog Hylarana erythraea (Ranidae).

Peptidomic analysis of norepinephrine-stimulated skin secretions of the South-East Asian frog Hylarana erythraea (formerly Rana erythraea partim) has led to the identification of multiple peptides with antimicrobial activity. Structural characterization of the peptides demonstrated that they belong to the brevinin-1 (3), brevinin-2 (2), esculentin-2 (4), and temporin (1) families. The values in parentheses indicate the number of paralogs.

Strategies for transformation of naturally-occurring amphibian antimicrobial peptides into therapeutically valuable anti-infective agents.

The emergence of strains of pathogenic microorganisms with resistance to commonly used antibiotics has necessitated a search for novel types of antimicrobial agents. Many frog species produce amphipathic alpha-helical peptides with broad spectrum antimicrobial activity in the skin but their therapeutic potential is limited by varying degrees of cytolytic activity towards eukaryotic cells. Methods for development of such peptides into anti-infective drugs are illustrated by the example of temporin-1DRa (HFLGTLVNLAK KIL.

Antimicrobial peptides from diverse families isolated from the skin of the Asian frog, Rana grahami.

Seven peptides with antimicrobial activity were isolated in pure form from an extract of the skin of the Yunnanfu Kunming frog Rana grahami Boulenger, 1917. The peptides were identified as belonging to the nigrocin-2 (three peptides), brevinin-1 (one peptide), brevinin-2 (three peptides), and esculentin-1 (one peptide) families. Nigrocin-2GRb (GLFGKILGVGKKVLCGLSGMC) containing three lysine residues, represented the peptide with highest potency against microorganisms (MIC = 3 microM against Escherichia coli, 12.

Antimicrobial peptides from the skin of the Tsushima brown frog Rana tsushimensis.

The Tsushima brown frog Rana tsushimensis Stejneger, 1907 exists in reproductive isolation on the island of Tsushima, Japan. Six peptides with antimicrobial activity were isolated in pure form from an extract of the skin of this species and their amino acid sequences identified them as members of the brevinin-1 (one peptide), brevinin-2 (one peptide) and temporin (four peptides) families. The C-terminally alpha-amidated brevinin-1 peptide (FLGSIVGALASALPSLISKIRN.

Pentadactylin: an antimicrobial peptide from the skin secretions of the South American bullfrog Leptodactylus pentadactylus.

Norepinephrine-stimulated skin secretions were obtained from male specimens of the South American bullfrog, Leptodactylus pentadactylus and shown to contain two peptides that inhibited the growth of microorganisms. The primary structure of a previously undescribed peptide, termed pentadactylin, was established as Gly-Leu-Leu-Asp-Thr-Leu-Lys-Gly-Ala-Ala-Lys-Asn-Val-Val-Gly-Ser-Leu-Ala-Ser-Lys-Val-Met-Glu-Lys-Leu.NH2.