Antimicrobial and Antibiofilm Activities of Helical Antimicrobial Peptide Sequences Incorporating Metal-Binding Motifs.

Antimicrobial peptides (AMPs) represent alternative strategies to combat the global health problem of antibiotic resistance. However, naturally occurring AMPs are generally not sufficiently active for use as antibiotics. Optimized synthetic versions incorporating additional design principles are needed. Here, we engineered amino-terminal Cu(II) and Ni(II) (ATCUN) binding motifs, which can enhance biological function, into the native sequence of two AMPs, CM15 and citropin1.1. The incorporation of metal-binding motifs modulated the antimicrobial activity of synthetic peptides against a panel of carbapenem-resistant enterococci (CRE) bacteria, including carbapenem-resistant Klebsiella pneumoniae (KpC+) and Escherichia coli (KpC+). Activity modulation depended on the type of ATCUN variant utilized. Membrane permeability assays revealed that the in silico selected lead template, CM15, and its ATCUN analogs increased bacterial cell death. Mass spectrometry, circular dichroism, and molecular dynamics simulations indicated that coordinating ATCUN derivatives with Cu(II) ions did not increase the helical tendencies of the AMPs. CM15 ATCUN variants, when combined with Meropenem, streptomycin, or chloramphenicol, showed synergistic effects against E. coli (KpC+ 1812446) biofilms. Motif addition also reduced the hemolytic activity of the wild-type AMP and improved the survival rate of mice in a systemic infection model. The dependence of these bioactivities on the particular amino acids of the ATCUN motif highlights the possible use of size, charge, and hydrophobicity to fine-tune AMP biological function. Our data indicate that incorporating metal-binding motifs into peptide sequences leads to synthetic variants with modified biological properties. These principles may be applied to augment the activities of other peptide sequences.

Trema orientalis Linn. Blume: A potential for prospecting for drugs for various uses.

Medicinal plants are used by traditional practitioners to treat several ailments. Ethnomedicinal studies on Trema orientalis Linn. Blume (Ulmaceae) have shown that it is used in the treatment of diabetes mellitus, respiratory diseases, oliguria, and malaria. This article is aimed at providing comprehensive information on the medicinal uses, biology, phytochemical constituents, and pharmacological data available on T. orientalis. This has been done to explore its therapeutic potential for future research opportunities. This review was compiled with information obtained from databases such as Medline, Elsevier, Springer, Science Direct, Pubmed, Google Scholar, and a library search for articles published in peer-reviewed journals. Compounds present in the plant include tannins, saponins, flavanoids, triterpenes, phytosterols, and several constituents of xanthones. Some pharmacological research done on the plant has focused on, hypoglycemic activity, analgesic, anti-inflammatory activities, anti-plasmodial activity, diuretic activity, laxativity effect, anti-convulsant activity, anti-helmintic activity, anti-sickling effect, anti-oxidant, and anti-bacterial activity. This compilation strongly supports the view that T. orientalis has beneficial therapeutic properties, and indicates its potential as an effective herbal remedy for several diseases. The promising results from several research works could be further substantiated by clinical trials.