Mechanism of Action of Recombinant Acc-Royalisin from Royal Jelly of Asian Honeybee against Gram-Positive Bacteria

Abstract

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.

Reciprocal cooperation of phytochemicals and micronutrients against typical and atypical forms ofBorreliasp.

“…The cellular permeability measured by UV‐absorbing release materials interpret to be mostly DNA, RNA and metabolites (Shen et al . ), as demonstrated in Fig. , showed to be significantly augmented after treatment of spirochaetes (logarithmic phase) and persistent forms (stationary phase) of B. burgdorferi and B. garinii with the combination of baicalein and luteolin, at concentration shown in our study to be bactericidal, respectively.…”

A fluorescently labeled undecapeptide derived from a protein in royal jelly of the honeybee—royalisin—for specific detection of oxidized low‐density lipoprotein

“…Royal jelly is a secretion of honeybee hypopharynx and mandibular salivary glands. Royalisin, which is a potent antimicrobial protein composed of 51 amino acid residues in royal jelly, has extensive sequence homology with sapecin and phormicins, both of which are composed of 40 amino acids . Nevertheless, the role of the extra stretch of 11 amino acid residues at the C‐terminus of royalisin (positions 41‐51), termed royalisin P11 (Figure ), remains unknown.…”

Synergy and mechanism of action of α-mangostin and ceftazidime against ceftazidime-resistant Acinetobacter baumannii

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