Antimicrobial peptides

About: Antimicrobial peptides is a research topic. Over the lifetime, 10645 publications have been published within this topic receiving 507688 citations. The topic is also known as: host defense peptide & antimicrobial protein.

Identification of a novel cathelicidin gene in the rainbow trout, Oncorhynchus mykiss

Abstract: We report the cloning of a novel antimicrobial peptide gene, termed rtCATH_1, found in the rainbow trout, Oncorhynchus mykiss. The predicted 216-residue rtCATH_1 prepropeptide consists of three domains: a 22-residue signal peptide, a 128-residue cathelin-like region containing two identifiable cathelicidin family signatures, and a predicted 66-residue C-terminal cationic antimicrobial peptide. This predicted mature peptide was unique in possessing features of different known (mammalian) cathelicidin subgroups, such as the cysteine-bridged family and the specific amino-acid-rich family. The rtCATH_1 gene comprises four exons, as seen in all known mammalian cathelicidin genes, and several transcription factor binding sites known to be of relevance to host defenses were identified in the 5′ flanking region. By Northern blot analysis, the expression of rtCATH_1 was detected in gill, head kidney, and spleen of bacterially challenged fish. Primary cultures of head kidney leukocytes from rainbow trout stimulated with lipopolysaccharide or poly(I · C) also expressed rtCATH_1. A 36-residue peptide corresponding to the core part of the fish cathelicidin was chemically synthesized and shown to exhibit potent antimicrobial activity and a low hemolytic effect. Thus, rtCATH_1 represents a novel antimicrobial peptide gene belonging to the cathelicidin family and may play an important role in the innate immunity of rainbow trout.

Mini-review: the role of peptidoglycan recognition in innate immunity.

Abstract: The importance of peptidoglycan detection in the host innate immune response has long been underestimated. However, the recent identification of proteins involved in the sensing of peptidoglycan in both mammals and Drosophila has revealed that the detection of this microbial motif is key to the defense response. In Drosophila, the peptidoglycan-recognition proteins (PGRP) are the initial sensors of infecting bacteria that then trigger a cascade ultimately leading to the expression of antimicrobial peptides. In mammals, PGRP also exist and although they bind peptidoglycan, the role of these proteins in innate immune responses remains to be clearly defined. In contrast, the Nod proteins (Nod1 and Nod2), which are also involved in peptidoglycan sensing, appear to play a key role in innate immunity against bacteria by triggering host defense responses through the activation of the transcription factor, NF-κB. Interstingly, mutations in Nod2 are related to increased susceptibility to Crohn's disease, thereby implicating defective bacterial sensing in the development at this chronic disease. In this review, we will focus on the recent findings concerning mammalian and Drosophila proteins involved in peptidoglycan recognition and the putative role of these proteins in the innate immune defense response. See an article in this issue http://dx.doi.org/10.1002/eji.200425229