Antimicrobial peptides and the interplay between microbes and host : towards preventing porcine infections with Streptococcus suis

Comparative genomics of Rothia species reveals diversity in novel biosynthetic gene clusters and ecological adaptation to different eukaryotic hosts and host niches

“…Valinomycin, identified only in Rothia nasisuis species, is an NRP ionophore, forming ion channels in membranes that allow free movement K + ions thereby, altering membrane potential that may lead to disruption of the normal K + ion membrane gradient [24, 54]. All isolates of R. nasisuis containing the valinomycin-producing NRPs showed inhibitory activity in vitro against Gram-positive target bacteria including different species of Streptococcus sp.…”

“…Recently, we showed that Rothia nasisuis colonizing the palatine tonsil epithelium of piglets produces the antimicrobial, antiviral and antiparasitic ionophore valinomycin in vivo , via a large multimodule non-ribosomal peptide synthetase (NRPS) enzyme complex encoded by genes tandemly arranged in a biosynthetic gene cluster (BGC) [ 24 ]. Biosynthetic gene clusters (BGCs) produce diverse metabolites including natural antimicrobial products that fall into three major metabolite groups: ribosomally synthesized and post-translationally modified peptides (RiPPs), non-ribosomal peptides (NRPs) and polyketides (PKs) [ 25 ].…”

Green Antimicrobials as Therapeutic Agents for Diabetic Foot Ulcers

“…There is a large diversity of known AMPs: more than 5000 antimicrobial peptides have been characterized and synthesized, and this number is expected to increase in the coming years [ 21 ]. Based on their structure, AMPs can be classified into four different groups: α-helical, extended, β-sheet, and cyclic [ 9 , 20 , 22 ]. Their secondary structures provide each peptide with a functional specificity [ 20 ].…”

“…Upon injury, the innate immune system recognizes pathogen-associated molecular patterns (PAMPs), including lipopolysaccharides (LPS) [ 2 ]. This, in turn, leads to the production of AMPs by skin resident cells, such as keratinocytes, and by infiltrating leukocytes, circulating neutrophils, and tissue macrophages [ 22 , 23 ]. As a result of the overexpression of these small molecules, the body is able to respond to injury and infection quickly and effectively [ 2 , 9 , 22 ].…”

“…These peptides can act as chemoattractants, recruiting and activating immune cells. This leads to the increasing expression of proinflammatory cytokines, thereby suppressing potentially harmful inflammation [ 2 , 9 , 20 , 22 ]. AMPs are also able to promote wound healing by the induction of cell migration, proliferation and differentiation, re-epithelization, support of angiogenesis, and enhancement of extracellular matrix synthesis [ 2 , 13 ].…”