title: Methylglyoxal-induced modifications of significant honeybee proteinous components in manuka honey: Possible therapeutic implications.
abstract: Methylglyoxal (MGO) is a major antibacterial component of manuka honey. Another antibacterial component found in Revamil honey, peptide defensin1, was not identified in manuka honey. The primary aim of the study was to evaluate the content of defensin1 in honeys of different botanical origins and to investigate a presumed effect of reactive MGO on defensin1 and a dominant protein of honey MRJP1 in manuka honey. Immunoblotting of honey samples showed that defensin1 was a regular but quantitatively variable component of honeys. One of the reasons of varying contents of defensin1 in different honeys seems to be constitutive but varying defensin1 expression in individual honeybees in bee populations that we documented on samples of nurse and forager bees by RT-PCR. Comparative analyses of honeys revealed a size modification of defensin1, MRJP1 and probably also α-glucosidase in manuka honey. We further showed that (i) the treatment of purified defensin1 in solution containing high amount of MGO caused a time-dependent loss of its antibacterial activity and (ii) increasing MGO concentrations in a non-manuka honey were connected with a gradual increase in the molecular weight of MRJP1. Obtained results demonstrate that MGO abrogates the antibacterial activity of defensin1 and modifies MRJP1 in manuka honey. We assume that MGO could also have negative effects on the structure and function of other proteins/peptides in manuka honey, including glucose oxidase, generating hydrogen peroxide.
authors.affiliation: Institute of Zoology, Slovak Academy of Sciences, Dubravska cesta 9, 845 06 Bratislava, Slovakia. juraj.majtan@savba.sk
authors.forename: Juraj
authors.initials: J
authors.lastname: Majtan
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Klaudiny
authors.forename: Jana
authors.initials: J
authors.lastname: Bohova
authors.forename: Lenka
authors.initials: L
authors.lastname: Kohutova
authors.forename: Maria
authors.initials: M
authors.lastname: Dzurova
authors.forename: Maria
authors.initials: M
authors.lastname: Sediva
authors.forename: Maria
authors.initials: M
authors.lastname: Bartosova
authors.forename: Viktor
authors.initials: V
authors.lastname: Majtan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D056705:Apitherapy; D001516:Bees; D023082:Defensins / Q000378:metabolism* / Q000494:pharmacology; D005949:Glucose Oxidase / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D006722:Honey / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000378:metabolism; D019476:Insect Proteins / Q000378:metabolism*; D008970:Molecular Weight; D010944:Plants; D011765:Pyruvaldehyde / Q000378:metabolism* / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D023082:Defensins; D006023:Glycoproteins; D019476:Insect Proteins; C559157:MRJP1 protein, Apis mellifera; D011765:Pyruvaldehyde; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; D000520:alpha-Glucosidases