The role of 10-hydroxy-Δ<sup>2</sup>-decenoic acid in the formation of fibrils of the major royal jelly protein 1/apisimin/24-methylenecholesterol complex isolated from honey bee (Apis mellifera) royal jelly

Abstract

Queen larvae of the honey bee (Apis mellifera) are fed with royal jelly, a glandular secretion produced by the hypopharyngeal and mandibular glands of worker honey bees. The necessary consistency of royal jelly is dependent on a protein-sterol complex (MRJP14/apisimin4/24MC8). At low pH, this complex forms fibrillar structures, which increase the viscosity of royal jelly. While the proteins in this complex are produced in the hypopharyngeal gland, the low pH is achieved by the secretion of the mandibular gland, which contains fatty acids. It is shown for the first time that fibril formation of MRJP14/apisimin4/24MC8 is not only induced by low pH via a buffer system, but also by the addition of the major fatty acid 10-hydroxy-Δ2-decenoic acid (10-HDA) of the mandibular gland secretion. This result further substantiates that fibril formation of the MRJP14/apisimin4/24MC8 complex only occurs after mixing the hypopharyngeal and mandibular gland secretions.