Metabolomics analysis of bee brains (Apis mellifera) in processes of memory acquisition

Abstract

Equipped with a mini-brain, smaller than one cubic millimeter and containing merely 950.000 neurons, the honeybee (Apis mellifera) could be indeed considered as having rather limited cognitive abilities. However, bees are characterized by a rich and plastic display of behavioral repertoire, contradicting the notion that insect behavior tends to be relatively inflexible and stereotypical. The honeybee has emerged as a robust and influential model for study of learning and memory formation, highlighting its utility for better understanding the basis of cognition. In this context, different metabolites (transmitters) were characterized by play distinct roles in learning and memory formation in insects. Considering that little is known about the metabolites associated with learning and development of cognitive skills in A. mellifera, the present study aims metabolomics analysis of bee brain subjected to behavioral test of Proboscis Extension Reflex (PER). For this purpose, the metabolomics analysis will be standardized using a LC-ESI-micrOToF-QIII MS and MSn system. Initially, a data bank of low molecular mass compounds characteristic of bee brain (neurotransmitters, free amino acids, polyamines, nucleotides, nucleosides, organic acids, etc.) will be created using the following parameters: chromatographic retention time, molecular mass and m/z values of the fragment-ions obtained under CID conditions, aiming to perform a quali- and quantitative analysis of metabolites present in the brains of individuals subjected to REP protocols and in the control group. The MALDI Spectral imaging strategy also will be applied to the identification of metabolites by mass spectrometry, with the aim to study and map the metabolites identified in honeybee brain section, as well as to get a better understanding of the distribution of these molecules in different brain structures, and try to establish a correlation with the tested behavior. The use of different methodological strategies implemented is expected to contribute to the understanding of neuroscience at the level of metabolites and their roles in molecular interactions and formation of long-term memory in bees. This strategy has a great potential to permit the discovery of novel compounds involved with memory acquisition in honeybees, which in turn may become future models for the rational development of novel drugs of neurological uses in diseases related to the cognition processes. (AU)