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Insight into the inhibitory activity and mechanism of bovine cathelicidin BMAP 27 against Salmonella Typhimurium.

Authors :
Xia, Rui
Xiao, Huazhi
Xu, Min
Hou, Luying
Han, Ye
Zhou, Zhijiang
Source :
Microbial Pathogenesis. Feb2024, Vol. 187, pN.PAG-N.PAG. 1p.
Publication Year :
2024

Abstract

This study synthesized an antimicrobial peptide based on the bovine cathelicidin BMAP 27 sequence. It was found to have a broad spectrum of antibacterial activity, with exceptionally high activity against Salmonella. However, the antibacterial mechanism of BMAP 27 against Salmonella remains unclear. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of BMAP 27 against Salmonella enterica serovar Typhimurium were determined to be 2 μM and 4 μM, respectively. After treatment with 2 MIC of BMAP 27, the absorbance of DNA in centrifugal supernatant increased from 0.244 to 1.464, and that of protein rose from 0.174 to 0.774, respectively. BMAP 27 has compromised the cell membrane as observed through field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM), and confirmed by the propidium iodide (PI) test. The alkaline phosphatase (AKP) enzyme activity in the supernatant of the 2 MIC treatment group was 2.15 times higher than the control group, indicating extracellular membrane damage. BMAP 27 treatment increased intracellular ROS levels as tested by dichlorofluorescein diacetate (DCFH) staining. DNA interaction analysis revealed that BMAP 27 has a binding affinity towards DNA, causing its characteristic bands to disappear and peak intensity at 260 nm to reduce. Molecular docking identified its potential binding mode with DNA. The crystal violet biofilm staining results demonstrated that BMAP 27 inhibited S. Typhimurium biofilm formation by 43.1 % and cleared mature biofilms by 53.62 %. Confocal Laser scanning electron microscopy (CLSM) observed that BMAP 27 could kill bacteria within the biofilm and dislodge bacteria from the surface of glasses. Swimming tests identified that the motor capacity of S. Typhimurium was diminished by BMAP 27. By counting the total bacteria, BMAP 27 was revealed to exert bacteriostatic effects in chilled pork and orange juice, which might provide a basis for its application in the inhibition of Salmonella. [Display omitted] • BMAP 27 exhibited a broad bacteriostatic spectrum and strong bacteriostatic action against S. Typhimurium. • BMAP 27 disrupted both integrity and permeability of cell membrane and cell wall of S. Typhimurium. • BMAP 27 induced intracellular ROS generation and accumulation. • BMAP 27 impaired the swimming capacity of S. Typhimurium, inhibited biofilm formation and removed mature biofilms. • BMAP 27 exhibited a non-covalent binding affinity towards S. Typhimurium genomic DNA. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
08824010
Volume :
187
Database :
Academic Search Index
Journal :
Microbial Pathogenesis
Publication Type :
Academic Journal
Accession number :
175137523
Full Text :
https://doi.org/10.1016/j.micpath.2024.106540