ABSTRACT
The consumption of royal jelly (RJ) determines the differences between castes and behavioral development in the honeybee Apis mellifera. However, it is not known whether the proteins of RJ are related to these differences, or which proteins are responsible for the changes. To understand the functions of RJ proteins that are present in other tissues of the bee, in addition to hypopharyngeal gland, we used a polyclonal antibody anti-MRJP1 to investigate the presence of this protein in nervous system of honeybee. This study showed the presence of three polypeptides (p57, p70 and p128) in specific tissues of bee brain. Mushroom body, optic lobe and antennal lobe neuropils all contained proteins recognized by anti-MRJP1. Proteomic analysis showed that the three polypeptides are correlated with proteins of the MRJP family. p57 is correlated with MRJP1, p70 with MRJP3, while p128 may be an oligomeric form or a new polypeptide. Immunostaining of the brain and hypopharyngeal gland revealed differential expression of MRJPs in various brain regions and in different honeybee castes and subcastes. The identification and localization of these MRJPs contribute to the elucidation of the biological roles of this protein family.
Subject(s)
Bees/chemistry , Insect Proteins/analysis , Nerve Tissue Proteins/analysis , Amino Acid Sequence , Animals , Bees/genetics , Bees/metabolism , Brain Chemistry , Gene Expression , Insect Proteins/chemistry , Insect Proteins/genetics , Insect Proteins/metabolism , Molecular Sequence Data , Molecular Weight , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Peptides/chemistry , Peptides/genetics , Peptides/metabolism , Protein Transport , ProteomicsABSTRACT
The honey bee (Apis mellifera) is a social insect that shows complex and integrated behaviors. Its ability to read and respond to several sets of extrinsic and intrinsic signals is fundamental for the modulation of individual activities and social systems. For instance, A. mellifera behavior changes upon the ontogenetic differentiation from nurse to forager worker subcastes. In this work, brain proteomes of nurses and foragers were compared by two-dimensional gel electrophoresis within pH range of 4-7 in order to find proteins related to such an ontogenetic and behavioral development. Twenty differentially expressed proteins were detected by gel image computational analysis, and identified by peptide mass fingerprinting using MALDI-TOF mass spectrometry. Nurse brain showed increased expression of major royal jelly proteins (MRJP1, MRJP2 and MRJP7), which are related to determination of castes during the honey bee larvae differentiation. Immunocytochemistry and electron microscopy showed that MRJP1 was localized in the cytoplasm of brain cells, seemingly along filaments of the cytoskeleton, in the antennal lobe, optical lobe and mushroom body. Also, MRJP1 was deposited on the rhabdom, a structure of the retinular cells, composed of numerous tubules. Such evidence suggests that MRJP1 could be associated to proteins of filamentous structures. MRJP1 was also found in intercellular spaces between cells in mushrooms bodies, indicating that it is a secreted protein. Other proteins implicated in protein synthesis and putative functions in the olfactory system were also up-regulated in the nurse brain. Experienced foragers overexpressed proteins possibly involved in energy production, iron binding, metabolic signaling and neurotransmitter metabolism. Such differential expression of proteins may be related to ontogenetic and behavior changes in A. mellifera.
Subject(s)
Bees/physiology , Behavior, Animal/physiology , Brain/physiology , Animals , Bees/growth & development , Brain/growth & development , Brain/ultrastructure , Electrophoresis, Gel, Two-Dimensional , Microscopy, Electron, Transmission , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
A method for the selective capture and analysis of peptides containing neither histidine nor arginine is evaluated. It is based on the reversible modification of alpha- and epsilon-amino groups of peptides and the relatively easy separation of charged and noncharged peptides by cation exchange chromatography. The simplicity of the method and the results obtained in silico and with standard proteins, anticipate the utility of the SCAPE approach for proteome analyses.
