TY - JOUR
T1 - Antimicrobial peptide zp37 inhibits Escherichia coli O157:H7 in alfalfa sprouts by inflicting damage in cell membrane and binding to DNA
AU - Yi, Lanhua
AU - Zeng, Ping
AU - Liu, Jun
AU - Wong, Kwok Yin
AU - Chan, Edward Wai Chi
AU - Lin, Yanbing
AU - Chan, Kin Fai
AU - Chen, Sheng
N1 - Funding Information:
Lanhua Yi: Acquired the financial support for the project leading to this publication, collected the data, Writing – review & editing. Ping Zeng: collected the data, Writing – review & editing. Jun Liu: collected the data. Kwok-Yin Wong: Formal analysis. Edward Wai-Chi Chan: Writing – review & editing. Yanbing Lin: Formal analysis. Kin-Fai Chan: Acquired the financial support for the project leading to this publication, Formal analysis. Sheng Chen: Acquired the financial support for the project leading to this publication, Formal analysis, Writing – review & editing.
Publisher Copyright:
© 2021
PY - 2021/7
Y1 - 2021/7
N2 - Due to frequent outbreaks of sprouts-associated foodborne illness, sprouts have been considered as a “high risk” food. In this study, the antimicrobial peptide zp37 (GIKAKIIIKIKK-NH2), which possesses a helical structure, was found to exhibit a minimum inhibitory concentration (MIC) value of 16 μM on E. coli O157:H7, effectively killing such strain in vitro and reducing its population size by 94.7% in sprouts upon storage for seven days. The effect of zp37 on cell membrane was investigated, with results showing that zp37 caused membrane depolarization and weak membrane permeabilization, which in turn resulted in cellular deformation observable by scanning electron microscope (SEM). Peptide zp37 was labeled by FITC to track the cellular location of zp37. Fluorescence microscopy studies showed that a larger amount of FITC-zp37 entered the bacterial cells when exposed to a higher concentration of the labeled peptide. Confocal microscopy showed that FITC-zp37 was detectable in cell membrane and cytoplasm. Upon entering the cytoplasm, zp37 was found to bind to the DNA of E. coli O157:H7, causing DNA aggregation and precipitation. Moreover, in vitro (HEK293 cell) and in vivo (Galleria mellonella) assays demonstrated that zp37 exhibited low toxicity.
AB - Due to frequent outbreaks of sprouts-associated foodborne illness, sprouts have been considered as a “high risk” food. In this study, the antimicrobial peptide zp37 (GIKAKIIIKIKK-NH2), which possesses a helical structure, was found to exhibit a minimum inhibitory concentration (MIC) value of 16 μM on E. coli O157:H7, effectively killing such strain in vitro and reducing its population size by 94.7% in sprouts upon storage for seven days. The effect of zp37 on cell membrane was investigated, with results showing that zp37 caused membrane depolarization and weak membrane permeabilization, which in turn resulted in cellular deformation observable by scanning electron microscope (SEM). Peptide zp37 was labeled by FITC to track the cellular location of zp37. Fluorescence microscopy studies showed that a larger amount of FITC-zp37 entered the bacterial cells when exposed to a higher concentration of the labeled peptide. Confocal microscopy showed that FITC-zp37 was detectable in cell membrane and cytoplasm. Upon entering the cytoplasm, zp37 was found to bind to the DNA of E. coli O157:H7, causing DNA aggregation and precipitation. Moreover, in vitro (HEK293 cell) and in vivo (Galleria mellonella) assays demonstrated that zp37 exhibited low toxicity.
KW - Antimicrobial peptide
KW - DNA binding
KW - E. coli O157:H7
KW - Membrane damage
KW - Sprouts
UR - http://www.scopus.com/inward/record.url?scp=85103696322&partnerID=8YFLogxK
U2 - 10.1016/j.lwt.2021.111392
DO - 10.1016/j.lwt.2021.111392
M3 - Journal article
AN - SCOPUS:85103696322
VL - 146
JO - LWT - Food Science and Technology
JF - LWT - Food Science and Technology
SN - 0023-6438
M1 - 111392
ER -