Membrane-active mechanism of LFchimera against Burkholderia pseudomallei and Burkholderia thailandensis

Abstract

LFchimera, a construct combining two antimicrobial domains of bovine lactoferrin, lactoferrampin265-284 and lactoferricin17-30, possesses strong bactericidal activity. As yet, no experimental evidence was presented to evaluate the mechanisms of LFchimera against Burkholderia isolates. In this study we analyzed the killing activity of LFchimera on the category B pathogen Burkholderia pseudomallei in comparison to the lesser virulent Burkholderia thailandensis often used as a model for the highly virulent B. pseudomallei. Killing kinetics showed that B. thailandensis E264 was more susceptible for LFchimera than B. pseudomallei 1026b. Interestingly the bactericidal activity of LFchimera appeared highly pH dependent; B. thailandensis killing was completely abolished at and below pH 6.4. FITC-labeled LFchimera caused a rapid accumulation within 15 min in the cytoplasm of both bacterial species. Moreover, freeze-fracture electron microscopy demonstrated extreme effects on the membrane morphology of both bacterial species within 1 h of incubation, accompanied by altered membrane permeability monitored as leakage of nucleotides. These data indicate that the mechanism of action of LFchimera is similar for both species and encompasses disruption of the plasma membrane and subsequently leakage of intracellular nucleotides leading to cell dead.

Bovine Lactoferrin and Lactoferrin-Derived Peptides Inhibit the Growth of Vibrio cholerae and Other Vibrio species

“…Nonetheless, LFcin17-30 and LFampin265-284 may be antibacterial, due they were able to damage membranes and cause disruption on V. cholerae cells (Figures 2–4 ). The more effective antibacterial ability of LFchimera compared to the effect reached with native bLF, LFcin17-30, and LFampin265-284 peptides has been reported for other bacteria, as well as parasites or fungi (Bolscher et al, 2009 ; Kanthawong et al, 2014 ; Leon-Sicairos et al, 2014 ). These differences on the effect could be due to the LFchimera structure (Haney et al, 2012a , b ).…”

“…The bactericidal activity of LFchimera has been definitively stronger than that of the peptides (LFcin17-30 and LFampin265-284), as has been demonstrated in many experiments; due to lower concentrations, shorter incubation time, and salt concentrations present in the environment (needed for the growth of halophile bacteria) permit the bactericidal activity of LF chimera, compared with the peptides that conform this molecule which is not effective at these conditions (Bolscher et al, 2009 ; Haney et al, 2009 ; Leon-Sicairos et al, 2014 ). Otherwise, the microbicidal effect of LFchimera against Candida spp, Vibrio parahaemolyticus, Staphylococcus aureus , enterotoxigenic and enterohaemorragic Escherichia coli , or in the parasites Entamoeba histolytica, Burkholderia thailandensis , and Leishmania pifanoi has been established in vitro (Bolscher et al, 2009 ; Lopez-Soto et al, 2009 , 2010 ; Flores-Villasenor et al, 2010 , 2012 ; Kanthawong et al, 2014 ; Leon-Sicairos et al, 2014 ; Puknun et al, 2016 ).…”

Synergistic effects of LFchimera and antibiotic against planktonic and biofilm form of Aggregatibacter actinomycetemcomitans

“…In contrast, all the peptides showed killing activity even at low concentrations. The mechanism of action of most AMPs against microbes involved disrupting the membrane or forming pores in the membrane resulting in leakage of essential ions and vital constituents such as intracellular nucleotides leading to cell dead [36, 37]. IDR-1018 was originally synthesized for immunomodulatory activity.…”

Iron transport mechanism of lactoferrin and its application in food processing

“…(Arab et al, 2017) Anti-bacterial Burkholderia A construct combining two antimicrobial structural domains of bLF lactoferrampin265-284 and lactoferricin17-30 resulted in disruption of the bacterial plasma membrane and subsequent leakage of intracellular nucleotides leading to cell death. (Kanthawong et al, 2014) Vibrio Cholerae bLF interacts directly with the negatively charged components of the microbial membrane, inducing changes in their permeability by dispersing them.…”