Mechanism of Action of Recombinant Acc-Royalisin from Royal
Jelly of Asian Honeybee against Gram-Positive Bacteria
PLoS ONE, 7(10): e47194
The antibacterial activity of royalisin, an antimicrobial
peptide from the royal jelly produced by honeybees, has been addressed
extensively. However, its mechanism of action remains unclear.
In this study, a recombinant royalisin, RAcc-royalisin from
the royal jelly of Asian honeybee Apis cerana cerana, was expressed by fusing
with glutathione S-transferase (GST) in Escherichia coli BL21, isolated and
purified. The agar dilution assays with inhibition zone showed that
RAcc-royalisin, similar to nisin, inhibits the growth of Gram-positive
bacteria.
The antibacterial activity of RAcc-royalisin was associated
with its concentration, and was weakened by heat treatment ranging from 55°C to
85°C for 15 min. Both RAcc-royalisin and nisin exhibited the minimum inhibitory
concentrations (MIC) of 62.5 µg/ml, 125 µg/ml, and 250 µg/ml against
Gram-positive bacterial strains, Bacillus subtilis and Micrococcus flavus and
Staphyloccocus aureus in the microplate assay, respectively. However,
RAcc-royalisin did not show antimicrobial activity against tested Gram-negative
bacterial and fungal strains. The antibacterial activity of RAcc-royalisin
agrees well with the decrease in bacterial cell hydrophobicity, the leakage of
260-nm absorbing materials, and the observation by transmission electron
microscopy, all indicating that RAcc-royalisin induced the disruption and
dysfunction of cell walls and membranes.
This is the first report detailing the antibacterial
mechanism of royalisin against Gram-positive bacteria, and provides insight
into the application of recombinant royalisin in food and pharmaceutical
industries as an antimicrobial agent.
No comments:
Post a Comment