Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella

To explore the antibacterial effect and mechanism of antimicrobial peptide LL-1 against Salmonella, the minimum inhibitory concentration (MIC) was determined by the doubling dilution method, and the antibacterial effect was evaluated by the growth inhibition curve. Then, the bacterial morphology was...

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Main Author: WANG Yuhang, ZHOU Lingling, ZHOU Yaoling, SA Junmeng, ZHANG Yuanchen, MA Zengjun, LIAN Kaiqi
Format: Article
Language:English
Published: China Food Publishing Company 2025-02-01
Series:Shipin Kexue
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Online Access:https://www.spkx.net.cn/fileup/1002-6630/PDF/2025-46-4-012.pdf
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author WANG Yuhang, ZHOU Lingling, ZHOU Yaoling, SA Junmeng, ZHANG Yuanchen, MA Zengjun, LIAN Kaiqi
author_facet WANG Yuhang, ZHOU Lingling, ZHOU Yaoling, SA Junmeng, ZHANG Yuanchen, MA Zengjun, LIAN Kaiqi
author_sort WANG Yuhang, ZHOU Lingling, ZHOU Yaoling, SA Junmeng, ZHANG Yuanchen, MA Zengjun, LIAN Kaiqi
collection DOAJ
description To explore the antibacterial effect and mechanism of antimicrobial peptide LL-1 against Salmonella, the minimum inhibitory concentration (MIC) was determined by the doubling dilution method, and the antibacterial effect was evaluated by the growth inhibition curve. Then, the bacterial morphology was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of LL-1 on the cell wall and cell membrane of Salmonella was evaluated by detecting the leakage of intracellular nucleic acids, proteins and alkaline phosphatase (ALP) as well as by conducting propidium iodide (PI) staining experiments. The binding of LL-1 to Salmonella DNA was detected by nucleic acid gel electrophoresis. Finally, the effect of LL-1 on the energy metabolism of Salmonella was evaluated by measuring the activities of intracellular succinate dehydrogenase (SDH), NADP-malate dehydrogenase (NADP-MDH) and ATP levels. The results showed that the MIC was 6.25 μg/mL, and LL-1 had a good antibacterial effect in dose- and time-dependent manners. Salmonella treated with LL-1 showed morphological changes such as cell shrinkage, cell membrane dissolution, and plasmolysis. LL-1 resulted in the leakage of intracellular nucleic acids, proteins and ALP and an increase in the fluorescence intensity of PI-stained bacterial cells. Additionally, LL-1 could bind to bacterial DNA. Increasing LL-1 concentration resulted in a decrease in the intracellular ATP content, SDH and NADP-MDH activities. In conclusion, LL-1 could exert its antibacterial activity against Salmonella by increasing the permeability of the cell membrane and cell wall, thereby causing the leakage of intracellular contents, binding to DNA, and affecting bacterial energy metabolism. This study lays the foundation for further research on the antibacterial mechanism and application of LL-1.
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spelling doaj-art-e4b8cfb49e82407e817001ecc101812a2025-08-20T03:11:54ZengChina Food Publishing CompanyShipin Kexue1002-66302025-02-0146411011610.7506/spkx1002-6630-20240602-002Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against SalmonellaWANG Yuhang, ZHOU Lingling, ZHOU Yaoling, SA Junmeng, ZHANG Yuanchen, MA Zengjun, LIAN Kaiqi0(1. School of Biology and Food Engineering, Anyang Institute of Technology, Anyang 455000, China; 2. College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China; 3. Henan Joint International Research Laboratory of Veterinary Biologics Research and Application, Anyang 455000, China; 4. Taihang Mountain Forest Pests Observation and Research Station of Henan Province, Linzhou 456550, China)To explore the antibacterial effect and mechanism of antimicrobial peptide LL-1 against Salmonella, the minimum inhibitory concentration (MIC) was determined by the doubling dilution method, and the antibacterial effect was evaluated by the growth inhibition curve. Then, the bacterial morphology was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of LL-1 on the cell wall and cell membrane of Salmonella was evaluated by detecting the leakage of intracellular nucleic acids, proteins and alkaline phosphatase (ALP) as well as by conducting propidium iodide (PI) staining experiments. The binding of LL-1 to Salmonella DNA was detected by nucleic acid gel electrophoresis. Finally, the effect of LL-1 on the energy metabolism of Salmonella was evaluated by measuring the activities of intracellular succinate dehydrogenase (SDH), NADP-malate dehydrogenase (NADP-MDH) and ATP levels. The results showed that the MIC was 6.25 μg/mL, and LL-1 had a good antibacterial effect in dose- and time-dependent manners. Salmonella treated with LL-1 showed morphological changes such as cell shrinkage, cell membrane dissolution, and plasmolysis. LL-1 resulted in the leakage of intracellular nucleic acids, proteins and ALP and an increase in the fluorescence intensity of PI-stained bacterial cells. Additionally, LL-1 could bind to bacterial DNA. Increasing LL-1 concentration resulted in a decrease in the intracellular ATP content, SDH and NADP-MDH activities. In conclusion, LL-1 could exert its antibacterial activity against Salmonella by increasing the permeability of the cell membrane and cell wall, thereby causing the leakage of intracellular contents, binding to DNA, and affecting bacterial energy metabolism. This study lays the foundation for further research on the antibacterial mechanism and application of LL-1.https://www.spkx.net.cn/fileup/1002-6630/PDF/2025-46-4-012.pdfsalmonella; antimicrobial peptides; antimicrobial mechanism; foodborne pathogens; cell membrane; energy metabolism
spellingShingle WANG Yuhang, ZHOU Lingling, ZHOU Yaoling, SA Junmeng, ZHANG Yuanchen, MA Zengjun, LIAN Kaiqi
Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella
Shipin Kexue
salmonella; antimicrobial peptides; antimicrobial mechanism; foodborne pathogens; cell membrane; energy metabolism
title Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella
title_full Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella
title_fullStr Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella
title_full_unstemmed Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella
title_short Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella
title_sort antimicrobial mechanism of antimicrobial peptide ll 1 against salmonella
topic salmonella; antimicrobial peptides; antimicrobial mechanism; foodborne pathogens; cell membrane; energy metabolism
url https://www.spkx.net.cn/fileup/1002-6630/PDF/2025-46-4-012.pdf
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