Peptides with antimicrobial activity of the brevinin‐1 family isolated from skin secretions of the southern leopard frog, Rana sphenocephala

Abstract

Three peptides with growth-inhibitory activity towards the gram-negative bacterium Eschericia coli were isolated from electrically stimulated secretions from the skin of the southern leopard frog, Rana sphenocephala. Structural characterization demonstrated that the peptides [brevinin-1Sa, minimum inhibitory concentration (MIC) = 55 microM; brevinin-1Sb, MIC = 17 microM; brevinin-1Sc, MIC = 14 microM] represent new members of the brevinin-1 family of antimicrobial peptides, previously isolated from several other species of frogs of the genus Rana. Their high concentration in skin secretions and extreme variability in amino acid sequence suggest that the brevinin family of peptides may be of value as molecular markers for the identification and taxonomic classification of Ranid frogs.

Peptides with antimicrobial activity from four different families isolated from the skins of the North American frogs Rana luteiventris, Rana berlandieri and Rana pipiens

“…Once a larger data set of primary structures has been compiled, the amino‐acid sequences may form a basis for cladistic analysis to investigate phylogenetic interrelationships between species. Skin secretions, containing very high concentrations of antimicrobial peptides, can easily be collected from Ranid frogs by noninvasive procedures (mild electrical stimulation or subcutaneous injection of epinephrine [10,16,17]) so that identification of the species does not necessitate sacrifice of the animal. Molecular techniques have been used previously to facilitate identification and to study phylogenetic relationships among Ranid frogs.…”

“…Frogs from the genus Rana constitute an extremely diverse and widely distributed group, with an estimated 250 species world‐wide and at least 36 species having been identified in North America [12]. Analysis of skin secretions and/or skin extracts of different species of Ranid frogs has led to the characterization of gaegurins [13] and rugosins [14] from Rana rugosa , brevinins from Rana brevipoda porsa [15], Rana esculenta [16] and Rana sphenocephala [17], esculentins [18] from R. esculenta , ranalexin [19] and ranatuerins [20] from Rana catesbeiana , and temporins [21] and ranatuerin 1T [22] from Rana temporaria . Peptides of the brevinin family have also been isolated from an extract of gastric tissue from R. esculenta [23].…”

Antibacterial peptides isolated from insects

“…One of these peptides is the 21-mer thanatin from the spined stink bug, Podisus maculiventris [66]. Thanatin is important in the sense that it contains a disulfide bridge and displays sequence similarity to the brevinins, antimicrobial peptides isolated from frog skin [67]. The sequence of the second peptide, moricin, from B. mori [68], apparently does not resemble that of any other antibacterial peptide.…”

The short proline-rich antibacterial peptide family

“…Vol. 59,2002 Review Article 1139 skin secretions [20], moricin, from Bombyx mori, apparently does not resemble any other antibacterial peptide [21]. In general, all antimicrobial peptides interact with the bacterial cell membrane.…”