@article {96165, title = {Search Behavior of Individual Foragers Involves Neurotransmitter Systems Characteristic for Social Scouting}, journal = {Front. Insect Sci}, year = {2021}, month = {06/2021}, abstract = {

In honey bees search behavior occurs as social and solitary behavior. In the context of foraging, searching for food sources is performed by behavioral specialized foragers, the scouts. When the scouts have found a new food source, they recruit other foragers (recruits). These recruits never search for a new food source on their own. However, when the food source is experimentally removed, they start searching for that food source. Our study provides a detailed description of this solitary search behavior and the variation of this behavior among individual foragers. Furthermore, mass spectrometric measurement showed that the initiation and performance of this solitary search behavior is associated with changes in glutamate, GABA, histamine, aspartate, and the catecholaminergic system in the optic lobes and central brain area. These findings strikingly correspond with the results of an earlier study that showed that scouts and recruits differ in the expression of glutamate and GABA receptors. Together, the results of both studies provide first clear support for the hypothesis that behavioral specialization in honey bees is based on adjusting modulatory systems involved in solitary behavior to increase the probability or frequency of that behavior.

}, doi = {10.3389/finsc.2021.664978}, author = {Chatterjee, Arumoy and Bais, Deepika and Brockmann, Axel and Ramesh, Divya} } @article {86474, title = {Downregulation of the tyrosine degradation pathway extends lifespan.}, journal = {Elife}, volume = {9}, year = {2020}, month = {2020 Dec 15}, abstract = {

Aging is characterized by extensive metabolic reprogramming. To identify metabolic pathways associated with aging, we analyzed age-dependent changes in the metabolomes of long-lived . Among the metabolites that changed, levels of tyrosine were increased with age in long-lived flies. We demonstrate that the levels of enzymes in the tyrosine degradation pathway increase with age in wild-type flies. Whole-body and neuronal-specific downregulation of enzymes in the tyrosine degradation pathway significantly extends lifespan, causes alterations of metabolites associated with increased lifespan, and upregulates the levels of tyrosine-derived neuromediators. Moreover, feeding wild-type flies with tyrosine increased their lifespan. Mechanistically, we show that suppression of ETC complex I drives the upregulation of enzymes in the tyrosine degradation pathway, an effect that can be rescued by tigecycline, an FDA-approved drug that specifically suppresses mitochondrial translation. In addition, tyrosine supplementation partially rescued lifespan of flies with ETC complex I suppression. Altogether, our study highlights the tyrosine degradation pathway as a regulator of longevity.

}, issn = {2050-084X}, doi = {10.7554/eLife.58053}, author = {Parkhitko, Andrey A and Ramesh, Divya and Wang, Lin and Leshchiner, Dmitry and Filine, Elizabeth and Binari, Richard and Olsen, Abby L and Asara, John M and Cracan, Valentin and Rabinowitz, Joshua D and Brockmann, Axel and Perrimon, Norbert} } @article {45302, title = {Mass Spectrometric Quantification of Arousal Associated Neurochemical Changes in Single Honey Bee Brains and Brain Regions.}, journal = {ACS Chem Neurosci}, volume = {10}, year = {2019}, month = {2018 Oct 26}, pages = {950-1959}, abstract = {

Honey bee foragers show a strong diurnal rhythm of foraging activity, and such behavioral changes are likely under the control of specific neuromodulators. To identify and quantify neuromodulators involved in regulating rest and arousal in honey bees, we established a mass spectrometric method for quantifying 14 different neurochemicals and precursor molecules. We measured forager type and brain region specific differences in amine levels from individual honey bee brains and brain regions. The observed differences in amine levels between resting and aroused foragers resemble findings in other species indicating a conserved molecular mechanism by glutamate and GABA in regulating arousal. Subesophageal ganglion specific changes in the histaminergic system and global increases in aspartate during arousal suggest a possible role of histamine and aspartate in feeding and arousal, respectively. More aminergic systems were significantly affected due to arousal in nectar foragers than in pollen foragers, implying that forager phenotypes differ not only in their food preference but also in their neuromodulatory signaling systems (brain states). Finally, we found that neurotransmitter precursors were better at distinguishing brain states in the central brain, while their end products correlated with arousal associated changes in sensory regions like the optic and antennal lobes.

}, issn = {1948-7193}, doi = {10.1021/acschemneuro.8b00254}, author = {Ramesh, Divya and Brockmann, Axel} } @article {26284, title = {Octopamine Drives Endurance Exercise Adaptations in Drosophila.}, journal = {Cell Rep}, volume = {21}, year = {2017}, month = {2017 Nov 14}, pages = {1809-1823}, abstract = {

Endurance exercise is an effective therapeutic intervention with substantial pro-healthspan effects. Male Drosophila respond to a ramped daily program of exercise by inducing conserved physiological responses similar to those seen in mice and humans. Female flies respond to an exercise stimulus but do\ not experience the adaptive training response seen in males. Here, we use female flies as a model\ to demonstrate that differences in exercise response are mediated by differences in neuronal activity. The activity of octopaminergic neurons is specifically required to induce the conserved cellular and physiological changes seen following endurance training. Furthermore, either intermittent, scheduled activation of octopaminergic neurons or octopamine feeding is able to fully substitute for exercise, conferring a suite of pro-healthspan benefits to sedentary Drosophila. These experiments indicate that octopamine is a critical mediator of adaptation to endurance exercise in Drosophila.

}, issn = {2211-1247}, doi = {10.1016/j.celrep.2017.10.065}, author = {Sujkowski, Alyson and Ramesh, Divya and Brockmann, Axel and Wessells, Robert} } @article {1619, title = {Agatoxin-like peptides in the neuroendocrine system of the honey bee and other insects.}, journal = {J Proteomics}, volume = {132}, year = {2016}, month = {2016 Jan 30}, pages = {77-84}, abstract = {

UNLABELLED: We investigated the peptide inventory of the corpora cardiaca (CC) of the honey bee, Apis mellifera, by direct tissue profiling using MALDI-TOF MS combined with proteomic approaches focusing on cysteine-containing peptides. An agatoxin-like peptide (ALP) was identified as a component of the glandular part of the CC and was associated with the presence of the adipokinetic hormone in mass spectra. Although abundant in the CC, ALP does not belong to the toxins observed in the venom gland of A. mellifera. Homologs of ALP are highly conserved in major groups of arthropods and in line with this we detected ALP in the CC of non-venomous insects such as cockroaches and silverfish. In the American cockroach, Periplaneta americana, ALP was also identified in the CNS and stomatogastric nervous system. This is the first report that establishes the presence of ALPs in the neuroendocrine tissues of insects and further studies are necessary to reveal common functions of these peptides, e.g. as antimicrobial agents, ion channel modulators or classical neuropeptides.

BIOLOGICAL SIGNIFICANCE: Among the messenger molecules of the nervous system, neuropeptides represent the structurally most diverse class and basically participate in the regulation of all physiological processes. The set of neuropeptides, their functions and spatial distribution are particularly well-studied in insects. Until now, however, several potential neuropeptide receptors remained orphan, which indicates the existence of so far unknown ligands. In our study, we used proteomic methods such as cysteine modification, enzymatic digestion and peptide derivatization, combined with direct tissue profiling by MALDI-TOF mass spectrometry, for the discovery of novel putative messenger molecules in the neuroendocrine system. The described presence of agatoxin-like peptides in the nervous system of the honey bee and other insects was overseen so far and is thus a remarkable addition to the very well studied neuropeptidome of insects. It is not yet clear, if these toxin-like peptides act as antimicrobial agents, ion channel modulators or classical neuropeptides.

}, issn = {1876-7737}, doi = {10.1016/j.jprot.2015.11.021}, author = {Sturm, Sebastian and Ramesh, Divya and Brockmann, Axel and Neupert, Susanne and Predel, Reinhard} }