title: [Biological characteristics of a human specifically targeted antimicrobial peptide C16LL-37 against Streptococcus mutans].
abstract: OBJECTIVE
  This study aimed to evaluate the biological characteristics of a human specifically targeted antimi- crobial peptide C16LL-37 against Streptococcus mutans (S. mutans).
  
  
  METHODS
  In this study, an antimicrobial peptide LL-37, a peptide derived from CSP(C16) (S. mutans competence stimulating peptide), and recombinant peptide C16LL-37 were synthesized by Fmoc-chemistry-based strategy. The selectivity and antibacterial activity of C16LL-37 were identified by the colony counting method on microbial culture plates. After treatment of C16LL-37 at 32 µmol · L⁻¹, the morphological changes in S. mutans were observed by using scanning electron microscopy (SEM). In addition, enzyme-linked immunosorbent assay was used to evaluate the hemolytic activity and antibacterial activity of C16LL-37 under different conditions.
  
  
  RESULTS
  1) The minimum inhibitory concentration of C16LL-37 was 16 µmol · L⁻¹, and the minimum bactericidal concentration was 64 μmol ·L⁻¹. 2) The survival rate of S. mutans was 3.46% after C16LL-37 treatment at 64 µmo-L⁻¹ for 30 min, whereas it was 0% at 64 µmol · L⁻¹ for 60 min. The survival rates of four other kinds of bacteria were more than 60% at any time (P < 0.05). 3) The morphological change in S. mutans was observed after C16LL-37 treatment at 32 µmol · L⁻¹ by using SEM. S. mutans presented an irregular shape, rough surface, and evident splitting. 4) The hemolysis rate of C16LL-37 (≤ 64 µmol · L⁻¹) was less than 0.33%. 5) This study showed no significant in- fluence on the antibacterial activity of C16LL-37 under different conditions, such as temperature, pH, salinity, and trypsin at low concentration (P > 0.05).
  
  
  CONCLUSIONS
  C16LL-37 exhibited obvious specificity for S. mutans, strong antibacterial activity, low toxicity, and high stability. Thus, C16LL-37 has good potential in caries research and clinical application.
authors.forename: Che
authors.initials: C
authors.lastname: Chunxiao
authors.forename: Jiang
authors.initials: J
authors.lastname: Keyu
authors.forename: Ma
authors.initials: M
authors.lastname: Yuanyuan
authors.forename: Zeng
authors.initials: Z
authors.lastname: Sa
authors.forename: Zhou
authors.initials: Z
authors.lastname: Jianye
authors.forename: Li
authors.initials: L
authors.lastname: Zhiqiang
authors.forename: He
authors.initials: H
authors.lastname: Xiangyi
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D001426:Bacterial Proteins; D003731:Dental Caries; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D010455:Peptides; D013295:Streptococcus mutans / Q000187:drug effects*
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D001426:Bacterial Proteins; D010455:Peptides; C423628:competence factor, Streptococcus