Design of Host Defence Peptides for Antimicrobial and Immunity Enhancing Activities

Abstract

Host defense peptides are a vital component of the innate immune systems of humans, other mammals, amphibians, and arthropods. The related cationic antimicrobial peptides are also produced by many species of bacteria and function as part of the antimicrobial arsenal to help the producing organism reduce competition for resources from sensitive species. The antimicrobial activities of many of these peptides have been extensively characterized and the structural requirements for these activities are also becoming increasingly clear. In addition to their known antimicrobial role, many host defense peptides are also involved in a plethora of immune functions in the host. In this review, we examine the role of structure in determining antimicrobial activity of certain prototypical cationic peptides and ways that bacteria have evolved to usurp these activities. We also review recent literature on what structural components are related to these immunomodulatory effects. It must be stressed however that these studies, and the area of peptide research, are still in their infancy.

Sporicidal Activity of Synthetic Antifungal Undecapeptides and Control of Penicillium Rot of Apples

“…A similar behavior has been described for other antifungal peptides such as tetralipopeptides (28), the hexapeptide PAF26 (36), and several cecropinderived peptides (11,14). However, a correlation between cell permeation and antimicrobial activity is not always observed, because some antimicrobial peptides do not disrupt bacterial membranes or have additional modes of action, including intracellular targets (16,31,46,48).…”

Structure-Activity Relationship Study of Novel Peptoids That Mimic the Structure of Antimicrobial Peptides

“…Length variants of the amino acid lysine (e.g., ornithine) have been used in the synthesis of novel peptidomimetics with improved antibacterial and hemolytic activities (28,29). In order to see whether the length of the charged residue in peptoid 1 affects activity, a shorter monomer, Nae, was substituted for Nlys in peptoid 1.…”

Insect proteins as a potential source of antimicrobial peptides in livestock production. A review

“…Generally, smaller AMPs are considered to be less toxic to eukaryotes, but potential toxicity is always a matter of concern and has to be evaluated. Further, smaller peptides are considered to be more stabile (McPhee et al, 2005). In order to even minimalize the toxicity, the introduction of unusual amino acids or modification of the terminal regions, e.g., through acetylation, can be considered.…”

“…In order to even minimalize the toxicity, the introduction of unusual amino acids or modification of the terminal regions, e.g., through acetylation, can be considered. Further, the use of efficient medicine delivery systems like liposome encapsulation can be effective for the improvement of stability and reduction of potential toxicity (McPhee et al, 2005).…”