Based on the cathelicidin family antimicrobial peptide Hc-CATH derived from sea snake, the Hc-16 and Hc-15 of 16 and 15 amino acid residues, were designed. By using CCK8, minimal inhibitory concentration, ELISA and bio-layer interferometry assays, their cytotoxicity, antibacterial activity, anti-inflammatory activity, and LPS neutralization activity was examined. Compared with Hc-15, Hc-16 had lower cytotoxicity and better broad-spectrum antibacterial activity against pathogens including clinically resistant bacteria, with the minimum inhibitory concentration of only 4.69 μg/mL. Hc-16 inhibited the expression of inflammatory cytokines of TNF-α and IL-6 induced by LPS, so as to significantly reduce the inflammatory response induced by infection. In addition, structure-activity relationship studies have shown that the phenylalanine at the C- and N-terminals of Hc-16 played a crucial role in its antibacterial and anti-inflammatory activity. Altogether, the designed Hc-16 has an excellent prospect to be developed into a novel antibiotic.
Animals ; Anti-Bacterial Agents/pharmacology* ; Anti-Infective Agents ; Hydrophiidae ; Microbial Sensitivity Tests ; Pore Forming Cytotoxic Proteins

The identification of species primordium has been one of the hot issues in the identification of traditional Chinese medicine. Sea snake is one of the most valuable Chinese medicinal materials in China. In order to understand the origin and varieties of sea snake in the market, we studied the molecular identification of 46 sea snakes by cytochrome B(Cytb). After comparison and manual correction, the sequence length was 582 bp, and the content of A+T(58.9%) was higher than that of G+C(41.1%). There exist 197 variable sites and 179 parsimony-informative sites of the sequence. There are 44 kinds of sequence alignment with consistency equal to 100%, and 2 kinds equal to 96%. A total of 408 Cytb effective sequences were downloaded from GenBank database, with a total of 68 species. Phylogenetic tree of a total of 454 sea snake sequences with the samples in this study were constructed by neighbor-joining trees and Bayesian inference method, respectively, which can identify 42 samples of medicinal materials, while 4 samples can not be identified because of their low node support. The results showed that the species of the sea snake medicine were at least from 2 genera and 5 species, namely, Aipysurus eydouxii, Hydrophis curtus, H. caerulescen, H. curtus, H. ornatus and H. spiralis. This study suggested that the original species of commercial sea snake are very complex and can provide insight into the identification of sea snakes.
Animals ; Bayes Theorem ; China ; Cytochromes b/genetics* ; Hydrophiidae ; Medicine, Chinese Traditional ; Phylogeny