Structure and mode of action of a novel antibacterial peptide from the blood of Andrias davidianus

Abstract

Significance and Impact of the Study: The results of this study suggested the new perspectives about the mode of action of antimicrobial peptide (AMP) active against sensitive bacteria. The AMP was able to be in a random coiled state in aqueous solution but to change to a more rigid one in the presence of sensitive bacteria. Exposure to AMP might not lead to immediate death of treated bacteria, rather bacteria concentration decreased gradually flattening at a sublethal stage. These findings will help people to understand better how the AMPs activate against sensitive bacteria. AbstractAndrias davidianus is widely recognized in traditional medicine as a cure-all to treat a plethora of ailments. In a previous study, a novel antibacterial peptide named andricin B was isolated from A. davidianus blood. In this study, we investigated andricin B structure and its mode of action. Circular dichroism spectra suggested that andricin B adopts a random coil state in aqueous solution and a more rigid conformation in the presence of bacteria. Moreover propidium iodide/fluorescein diacetate double staining indicated that bacteria treated with andricin B were not immediately eliminated. Rather, there is a gradual bacterial death, followed by a sublethal stage. Scanning electronic microscope imaging indicates that andricin B might form pores on cell membranes, leading to the release of cytoplasmic contents. These results were consistent with flow cytometry analysis. Furthermore, Fourier transform infrared spectroscopy suggests that andricin B induces changes in the chemical properties in the areas surrounding these "pores" on the cell membranes.

Antioxidative Activity and Volatile Profiles of Maillard Reaction Products between Giant Salamander (Andrias davidianus) Peptides and Glucose during the Heating Process

“…As their price dropped sharply with increasing quantities and yields annually, further development and exploitation of huge amounts of farmed giant salamanders are greatly in demand. Currently, nutrition analysis of giant salamanders [3][4][5], bioactive peptides [6][7][8][9], collagen/gelatin [10][11][12], segmentation processing, storage, preservation [13][14][15], and other aspects are frequently reported. Along with the application and development trend of various food-derived bioactive peptides, functional peptides prepared from the meat of giant salamander by enzymatic hydrolysis have also been reported to have antioxidant, antibacterial, antidiabetes, and immuneenhancing efects [6][7][8][9].…”

“…Currently, nutrition analysis of giant salamanders [3][4][5], bioactive peptides [6][7][8][9], collagen/gelatin [10][11][12], segmentation processing, storage, preservation [13][14][15], and other aspects are frequently reported. Along with the application and development trend of various food-derived bioactive peptides, functional peptides prepared from the meat of giant salamander by enzymatic hydrolysis have also been reported to have antioxidant, antibacterial, antidiabetes, and immuneenhancing efects [6][7][8][9]. However, there are still some technical problems to be solved, such as a strong fshy smell, difculty in purifcation and enrichment of highly active components, and unclear activity mechanisms.…”

Identification of Antibacterial Activity of Hepcidin From Antarctic Notothenioid Fish

“…Since the 1950s, antibiotics have been widely used around the world to fend off pathogens. Unfortunately, multidrug-resistant microbes have evolved at an unprecedented rate and are insensitive to many current treatment ( Pei et al, 2019 ). In the 21st century, people have increasingly turned to study plants and animals in the hope of identifying and characterizing antimicrobial peptides with broad-spectrum antimicrobial activity and unique membrane-directed mechanism to replace traditional antibiotics ( Iman et al, 2019 ).…”

Influence of Frying Methods on Quality Characteristics and Volatile Flavor Compounds of Giant Salamander (Andrias davidianus) Meatballs

“…Giant salamander (Andrias davidianus), also known as "babyfish," is the largest amphibian in the world [1]. is species enjoys high edible and medicinal value, because its skin, skin secretion, muscle, blood, and bone contain many bio-active substances [2].…”