The synthesis of antimicrobial peptides in the skin ofRana esculentais stimulated by microorganisms

Abstract

Secretions of amphibian skin glands contain numerous antimicrobial peptides that play a crucial\ud role in the defense against microorganisms. The location of these glands on the surface of the\ud animal makes them a useful model for in vivo studies of the relationships between the innate\ud immune system and the natural flora. Here, we present the results of a study showing that in\ud Rana esculenta the total antimicrobial activity of skin secretion is modulated by the presence of\ud the natural flora. Frogs kept in a sterile environment do not produce antimicrobial peptides. This\ud finding represents the first in vivo demonstration of the induction of defense peptides in a\ud vertebrate. We also present data on the morphological changes in skin glands of animals kept in\ud sterile conditions or treated with glucocorticoids. Cells from glands regenerated under normal\ud conditions, but not those from “sterile” frogs, contain κB-binding activity in the cytoplasm

Comparative Analysis of the Bactericidal Activities of Amphibian Peptide Analogues against Multidrug-Resistant Nosocomial Bacterial Strains

“…The skin of amphibians, especially that of the frogs of the genus Rana, is a particularly rich source of AMPs, with each species producing its own specific set of peptides (7) which are stored in granules of holocrine-type dermal glands and which are released into skin secretions as a reaction to stress, injury, or contact with microorganisms (22,26).…”

Antimicrobial Peptide Defenses in the Salamander, Ambystoma Tigrinum, Against Emerging Amphibian Pathogens

“…Bacteria resident on the skin may be involved in stimulation of antimicrobial peptide production by salamanders, as observed with frogs (Miele et al, 1998;Boman, 2000;Mangoni et al, 2001), or may themselves produce antimicrobial substances (Jack et al, 1996). Similar bacterial species (Proteus mirabilis, Staphylococcus spp., Providentia (Proteus) rettgeri, Klebsiella spp.)…”

An integrated analysis of the effects of Esculentin 1–21 on Saccharomyces cerevisiae

“…To date, there is compelling evidence that a common step in the microbial killing mechanism is the electrostatic interaction of AMPs with the negatively charged cell membrane followed by its permeation/disruption [8] or with the actin cables of the cytoskeleton [9]. The amphibian skin secretions constitutes one of the richest sources of AMPs that are synthesized and stored within granules of holocrine-type serous glands and released upon stimulation [10,11]. Among the skin secretions of Rana esculenta, the esculentin-1 family of peptides, (containing 46-amino acids with a C-terminal hepta-membered ring stabilized by a disulphide bridge), is the most potent, being active against both Gram-positive and Gramnegative bacteria, yeasts and filamentous fungi, with negligible effects on eukaryotic cell membranes [12].…”