@article{KayaZeebDelacWolfetal.2022,
  author    = {Kaya-Zeeb, Sinan and Delac, Saskia and Wolf, Lena and Marante, Ana Luiza and Scherf-Clavel, Oliver and Thamm, Markus},
  title     = {Robustness of the honeybee neuro-muscular octopaminergic system in the face of cold stress},
  series = {Frontiers in Physiology},
  volume    = {13},
  journal   = {Frontiers in Physiology},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2022.1002740},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-288753},
  year      = {2022},
  abstract  = {In recent decades, our planet has undergone dramatic environmental changes resulting in the loss of numerous species. This contrasts with species that can adapt quickly to rapidly changing ambient conditions, which require physiological plasticity and must occur rapidly. The Western honeybee (Apis mellifera) apparently meets this challenge with remarkable success, as this species is adapted to numerous climates, resulting in an almost worldwide distribution. Here, coordinated individual thermoregulatory activities ensure survival at the colony level and thus the transmission of genetic material. Recently, we showed that shivering thermogenesis, which is critical for honeybee thermoregulation, depends on octopamine signaling. In this study, we tested the hypothesis that the thoracic neuro-muscular octopaminergic system strives for a steady-state equilibrium under cold stress to maintain endogenous thermogenesis. We can show that this applies for both, octopamine provision by flight muscle innervating neurons and octopamine receptor expression in the flight muscles. Additionally, we discovered alternative splicing for AmOARβ2. At least the expression of one isoform is needed to survive cold stress conditions. We assume that the thoracic neuro-muscular octopaminergic system is finely tuned in order to contribute decisively to survival in a changing environment.},
  language  = {en}
}
@article{KayaZeebEngelmayerStrassburgeretal.2022,
  author    = {Kaya-Zeeb, Sinan and Engelmayer, Lorenz and Straßburger, Mara and Bayer, Jasmin and B{\"a}hre, Heike and Seifert, Roland and Scherf-Clavel, Oliver and Thamm, Markus},
  title     = {Octopamine drives honeybee thermogenesis},
  series = {eLife},
  volume    = {11},
  journal   = {eLife},
  doi       = {10.7554/eLife.74334},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301327},
  year      = {2022},
  abstract  = {In times of environmental change species have two options to survive: they either relocate to a new habitat or they adapt to the altered environment. Adaptation requires physiological plasticity and provides a selection benefit. In this regard, the Western honeybee (Apis mellifera) protrudes with its thermoregulatory capabilities, which enables a nearly worldwide distribution. Especially in the cold, shivering thermogenesis enables foraging as well as proper brood development and thus survival. In this study, we present octopamine signaling as a neurochemical prerequisite for honeybee thermogenesis: we were able to induce hypothermia by depleting octopamine in the flight muscles. Additionally, we could restore the ability to increase body temperature by administering octopamine. Thus, we conclude that octopamine signaling in the flight muscles is necessary for thermogenesis. Moreover, we show that these effects are mediated by β octopamine receptors. The significance of our results is highlighted by the fact the respective receptor genes underlie enormous selective pressure due to adaptation to cold climates. Finally, octopamine signaling in the service of thermogenesis might be a key strategy to survive in a changing environment.},
  language  = {en}
}
@article{SchilcherThammStrubeBlossetal.2021,
  author    = {Schilcher, Felix and Thamm, Markus and Strube-Bloss, Martin and Scheiner, Ricarda},
  title     = {Opposing actions of octopamine and tyramine on honeybee vision},
  series = {Biomolecules},
  volume    = {11},
  journal   = {Biomolecules},
  number    = {9},
  issn      = {2218-273X},
  doi       = {10.3390/biom11091374},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246214},
  year      = {2021},
  abstract  = {The biogenic amines octopamine and tyramine are important neurotransmitters in insects and other protostomes. They play a pivotal role in the sensory responses, learning and memory and social organisation of honeybees. Generally, octopamine and tyramine are believed to fulfil similar roles as their deuterostome counterparts epinephrine and norepinephrine. In some cases opposing functions of both amines have been observed. In this study, we examined the functions of tyramine and octopamine in honeybee responses to light. As a first step, electroretinography was used to analyse the effect of both amines on sensory sensitivity at the photoreceptor level. Here, the maximum receptor response was increased by octopamine and decreased by tyramine. As a second step, phototaxis experiments were performed to quantify the behavioural responses to light following treatment with either amine. Octopamine increased the walking speed towards different light sources while tyramine decreased it. This was independent of locomotor activity. Our results indicate that tyramine and octopamine act as functional opposites in processing responses to light.},
  language  = {en}
}
@article{ScheinerEntlerBarronetal.2017,
  author    = {Scheiner, Ricarda and Entler, Brian V. and Barron, Andrew B. and Scholl, Christina and Thamm, Markus},
  title     = {The Effects of Fat Body Tyramine Level on Gustatory Responsiveness of Honeybees (Apis mellifera) Differ between Behavioral Castes},
  series = {Frontiers in Systems Neuroscience},
  volume    = {11},
  journal   = {Frontiers in Systems Neuroscience},
  number    = {55},
  doi       = {10.3389/fnsys.2017.00055},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157874},
  year      = {2017},
  abstract  = {Division of labor is a hallmark of social insects. In the honeybee (Apis mellifera) each sterile female worker performs a series of social tasks. The most drastic changes in behavior occur when a nurse bee, who takes care of the brood and the queen in the hive, transitions to foraging behavior. Foragers provision the colony with pollen, nectar or water. Nurse bees and foragers differ in numerous behaviors, including responsiveness to gustatory stimuli. Differences in gustatory responsiveness, in turn, might be involved in regulating division of labor through differential sensory response thresholds. Biogenic amines are important modulators of behavior. Tyramine and octopamine have been shown to increase gustatory responsiveness in honeybees when injected into the thorax, thereby possibly triggering social organization. So far, most of the experiments investigating the role of amines on gustatory responsiveness have focused on the brain. The potential role of the fat body in regulating sensory responsiveness and division of labor has large been neglected. We here investigated the role of the fat body in modulating gustatory responsiveness through tyramine signaling in different social roles of honeybees. We quantified levels of tyramine, tyramine receptor gene expression and the effect of elevating fat body tyramine titers on gustatory responsiveness in both nurse bees and foragers. Our data suggest that elevating the tyramine titer in the fat body pharmacologically increases gustatory responsiveness in foragers, but not in nurse bees. This differential effect of tyramine on gustatory responsiveness correlates with a higher natural gustatory responsiveness of foragers, with a higher tyramine receptor (Amtar1) mRNA expression in fat bodies of foragers and with lower baseline tyramine titers in fat bodies of foragers compared to those of nurse bees. We suggest that differential tyramine signaling in the fat body has an important role in the plasticity of division of labor through changing gustatory responsiveness.},
  language  = {en}
}
@phdthesis{Hoyer2007,
  author    = {Hoyer, Susanne Christine},
  title     = {Neuronal Correlates of Aggression in Drosophila melanogaster},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-25871},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2007},
  abstract  = {Aggression ist ein facettenreiches Ph{\"a}nomen, das sowohl in Vertebraten als auch in Invertebraten auftritt. Trotz der weiten Verbreitung dieses Verhaltens sind die neuronalen Netzwerke, die der Aggression zugrunde liegen, noch kaum bekannt. Zahlreiche Studien weisen den biogenen Aminen eine prominente Rolle in der Modulation von Aggression zu. Das Ziel dieser Doktorarbeit war mit Hilfe des Modellorganismus Drosophila melanogaster zu der Aufschl{\"u}sselung der neuronalen Korrelate von Aggression beizutragen, insbesondere im Hinblick auf das biogene Amin Oktopamin. In Drosophila sind aggressive Interaktionen aus einer Vielzahl von offensiven und defensiven Verhaltensweisen zusammengesetzt, von denen einige bez{\"u}glich der H{\"a}ufigkeit ihres Auftretens geschlechtsspezifisch sind. Um die Auswertung dieser vielseitigen Verhaltensweisen zu vereinfachen, wurde die Analyse auf einen einzigen Indikator f{\"u}r Aggression beschr{\"a}nkt: den „lunge". Diese bemerkenswerte Verhaltensweise tritt nur im Kontext der Aggression auf und ist charakteristisch f{\"u}r M{\"a}nnchen. In Kooperation mit Andreas Eckart habe ich ein Computerprogramm entwickelt, das eine automatische Ausz{\"a}hlung der lunges in einem vom Forscher gew{\"a}hlten Zeitraum durchf{\"u}hrt. Zus{\"a}tzlich erh{\"a}lt man u.a. Informationen {\"u}ber die Laufstrecke der einzelnen Tiere wie auch {\"u}ber ihre Gr{\"o}ße. Dank eines weiteren von uns entwickelten Programms ist es m{\"o}glich, K{\"a}mpfe zweier Drosophila M{\"a}nnchen unabh{\"a}ngig von deren Genotyp wahlweise automatisch oder halb-automatisch auszuwerten. Mit Hilfe dieser Programme wurde gezeigt, dass (1) die gemeinsame Laufaktivit{\"a}t der beiden M{\"a}nnchen mit der Anzahl aller aufgetretenen lunges korreliert und, dass (2) ein Gr{\"o}ßenunterschied von 8\% ausreichend ist, um zu beeinflussen, welches Tier mehr lunges durchf{\"u}hrt. Ebenfalls konnte festgestellt werden, dass (3) eine Nullmutation im ‚white' Gen, welches einen ABC-Transporter kodiert, aggressives Verhalten fast vollst{\"a}ndig unterdr{\"u}ckt, was teilweise auf eine visuelle Beeintr{\"a}chtigung zur{\"u}ckzuf{\"u}hren ist. Außerdem f{\"u}hrt (4) das Absenken des White-Levels in verschiedenen Bereichen des Zentralgehirns zu reduzierter Aggression; ein Effekt, der auch durch die chemische Entfernung der Pilzk{\"o}rper, einer Struktur des zentralen Gehirns, hervorgerufen werden kann. Dies weist darauf hin, dass die Integrit{\"a}t verschiedener neuronaler Netzwerke/Gehirnbereiche erforderlich ist, um wildtypische Aggression zu erm{\"o}glichen. Zus{\"a}tzlich konnte (5) anhand von Mutationen in zwei Genen der Oktopaminsynthese, die beide die Oktopamin-Konzentration zwar erniedrigen, die Tyramin-Konzentration jedoch heben bzw. senken, demonstriert werden, dass Oktopaminmangel Aggression fast vollst{\"a}ndig zum Erliegen bringt. Wird ein lunge durchgef{\"u}hrt, so ist dessen Ausf{\"u}hrung fast wildtypisch. Rettungsversuche, in denen Oktopamin- und/oder Tyramin-Konzentrationen wiederhergestellt werden, legen nahe, dass ein sehr spezifisches Muster von Oktopamin r{\"a}umlich und zeitlich gew{\"a}hrleistet sein muss, um ein so komplexes und faszinierendes Verhalten wie die Aggression in Drosophila hervorzurufen.},
  subject      = {Biogene Amine},
  language  = {en}
}