Antibacterial and Antibiofilm Activity of Temporin-GHc and Temporin-GHd Against Cariogenic Bacteria, Streptococcus mutans

Abstract

Temporin-GHc (GHc) and temporin-GHd (GHd) produced by the frog Hylarana guentheri had shown broad-spectrum antibacterial activities against bacteria and fungi. In this study, we investigated whether they exert antibacterial and antibiofilm activities against cariogenic bacteria, Streptococcus mutans. GHc and GHd adopt the random coil conformation in aqueous solution and convert to α-helix in membrane mimetic environments by using circular dichroism spectroscope. They are positively charged by histidine, with the polar and nonpolar amino acids on opposing faces along the helix. The amphipathicity enabled the peptides to target at bacterial membrane, leading to an increase in membrane permeation and disruption of S. mutans, which allowed the peptides to bind with genomic DNA. GHc and GHd completely impeded the initial attachment of biofilm formation and disrupted preformed S. mutans biofilms. The expression of exopolysaccharide (EPS) biosynthesis genes which synthesize glucosyltransferases in S. mutans was downregulated by exposing to GHc or GHd, contributing to the decrease of soluble and insoluble EPS. GHc and GHd exhibited selectivity toward S. mutans in the presence of human erythrocytes, and no cytotoxicity toward human oral epithelial cells was observed at a concentration of 200 μM. These results laid the foundation for the development of GHc and GHd as potential anti-caries agents.

Propolis nanoparticle enhances the potency of antimicrobial photodynamic therapy against Streptococcus mutans in a synergistic manner

“…Further investigation through affecting the gene expression of biofilm regulatory genes, including gtf genes and ftf were identified. A potent inhibitor of gtf genes is reported to be capable of reducing the amount of Gtfs in S. mutans biofilms, thereby inhibiting EPSs production and biofilm formation 34 . Munro et al 7 reported that inactivation of gtfB, -C or ftf drastically reduced virulence properties of S. mutans.…”

Aggregation and Its Influence on the Bioactivities of a Novel Antimicrobial Peptide, Temporin-PF, and Its Analogues

“…Moreover, forming oligomers in some microenvironments, such as lipopolysaccharides (LPS) of Gram-negative bacteria, could escalate the difficulty for temporin to traverse the outer membrane, which weakens the antimicrobial activity on Gram-negative bacteria [ 30 , 33 ]. Therefore, structural modifications and engineering have been continuously implemented for temporins to improve the therapeutic index and efficacy [ 20 , 26 , 30 , 34 ].…”

A Textile Pile Debridement Material Consisting of Polyester Fibers for in Vitro Removal of Biofilm

“…Meanwhile, a slimy barrier and adhesion are clearly observed among bacterial colonies under a high magnification view in Figure 14 b. The extracellular polysaccharide-wrapped bacterial colonies exhibit the typical features of biofilms [ 32 ], certifying a successful construction of an in vitro biofilm model.…”

“…Meanwhile, a slimy barrier and adhesion are clearly observed among bacterial colonies under a high magnification view in Figure 14b. The extracellular polysaccharide-wrapped bacterial colonies exhibit the typical features of biofilms [32], certifying a It can be seen from Figure 13 that the OD value of samples before the biofilm removal test was higher than 0.24, implying a biofilm with vigorous viability. All five curves after the removal tests have a significantly lower value than that of the control, suggesting an evident reduction in biofilm.…”