TY - THES A1 - Beer, Katharina T1 - A Comparison of the circadian clock of highly social bees (\(Apis\) \(mellifera\)) and solitary bees (\(Osmia\) \(spec.\)): Circadian clock development, behavioral rhythms and neuroanatomical characterization of two central clock components (PER and PDF) T1 - Ein Vergleich der Inneren Uhr von sozialen Bienen (\(Apis\) \(mellifera\)) und solitären Bienen (\(Osmia\) \(spec.\)): Entwicklung der circadianen Uhr, Verhaltensrhythmen und neuroanatomische Beschreibung von zwei zentralen Uhr Komponenten (PER und PDF) N2 - Summary Bees, like many other organisms, evolved an endogenous circadian clock, which enables them to foresee daily environmental changes and exactly time foraging flights to periods of floral resource availability. The social lifestyle of a honey bee colony has been shown to influence circadian behavior in nurse bees, which do not exhibit rhythmic behavior when they are nursing. On the other hand, forager bees display strong circadian rhythms. Solitary bees, like the mason bee, do not nurse their offspring and do not live in hive communities, but face the same daily environmental changes as honey bees. Besides their lifestyle mason and honey bees differ in their development and life history, because mason bees overwinter after eclosion as adults in their cocoons until they emerge in spring. Honey bees do not undergo diapause and have a relatively short development of a few weeks until they emerge. In my thesis, I present a comparison of the circadian clock of social honey bees (Apis mellifera) and solitary mason bees (Osmia bicornis and Osmia cornuta) on the neuroanatomical level and behavioral output level. I firstly characterized in detail the localization of the circadian clock in the bee brain via the expression pattern of two clock components, namely the clock protein PERIOD (PER) and the neuropeptide Pigment Dispersing Factor (PDF), in the brain of honey bee and mason bee. PER is localized in lateral neuron clusters (which we called lateral neurons 1 and 2: LN1 and LN2) and dorsal neuron clusters (we called dorsal lateral neurons and dorsal neurons: DLN, DN), many glia cells and photoreceptor cells. This expression pattern is similar to the one in other insect species and indicates a common ground plan of clock cells among insects. In the LN2 neuron cluster with cell bodies located in the lateral brain, PER is co-expressed with PDF. These cells build a complex arborization network throughout the brain and provide the perfect structure to convey time information to brain centers, where complex behavior, e.g. sun-compass orientation and time memory, is controlled. The PDF arborizations centralize in a dense network (we named it anterio-lobular PDF hub: ALO) which is located in front of the lobula. In other insects, this fiber center is associated with the medulla (accessory medulla: AME). Few PDF cells build the ALO already in very early larval development and the cell number and complexity of the network grows throughout honey bee development. Thereby, dorsal regions are innervated first by PDF fibers and, in late larval development, the fibers grow laterally to the optic lobe and central brain. The overall expression pattern of PER and PDF are similar in adult social and solitary bees, but I found a few differences in the PDF network density in the posterior protocerebrum and the lamina, which may be associated with evolution of sociality in bees. Secondly, I monitored activity rhythms, for which I developed and established a device to monitor locomotor activity rhythms of individual honey bees with contact to a mini colony in the laboratory. This revealed new aspects of social synchronization and survival of young bees with indirect social contact to the mini colony (no trophalaxis was possible). For mason bees, I established a method to monitor emergence and locomotor activity rhythms and I could show that circadian emergence rhythms are entrainable by daily temperature cycles. Furthermore, I present the first locomotor activity rhythms of solitary bees, which show strong circadian rhythms in their behavior right after emergence. Honey bees needed several days to develop circadian locomotor rhythms in my experiments. I hypothesized that honey bees do not emerge with a fully matured circadian system in the hive, while solitary bees, without the protection of a colony, would need a fully matured circadian clock right away after emergence. Several indices in published work and preliminary studies support my hypothesis and future studies on PDF expression in different developmental stages in solitary bees may provide hard evidence. N2 - Zusammenfassung Bienen, sowie viele andere Organismen, evolvierten eine innere circadiane Uhr, die es ihnen ermöglicht, tägliche Umweltveränderungen voraus zu sehen und ihre Foragierflüge zu Tageszeiten durchzuführen, wenn sie möglichst viele Blüten besuchen können. Es zeigte sich, dass der soziale Lebensstil der Honigbiene Einfluss auf das rhythmische Verhalten der Ammenbienen hat, die während der Brutpflege keinen täglichen Rhythmus im Verhalten aufweisen. Sammlerbienen auf der anderen Seite zeigen ein stark rhythmisches Verhalten. Solitäre Bienen, wie die Mauerbiene, betreiben keine Brutpflege und leben nicht in einer Staatengemeinschaft, aber sind den gleichen Umweltveränderungen ausgesetzt. Nicht nur Lebensstil, sondern auch Entwicklung und Lebenszyklus unterscheiden sich zwischen Honig- und Mauerbienen. Mauerbienen überwintern als adulte Insekten in einem Kokon bis sie im Frühjahr schlüpfen. Honigbienen durchleben keine Diapause und schlüpfen nach wenigen Wochen der Entwicklung im Bienenstock. In meiner Dissertation vergleiche ich die circadiane Uhr von sozialen Honigbienen (Apis mellifera) und solitären Mauerbienen (Osmia bicornis und Osmia cornuta) auf Ebene der Neuroanatomie und das durch die innere Uhr verursachte rhythmische Verhalten. Erstens charakterisierte ich detailliert die Lage der circadianen Uhr im Gehirn von Honig- und Mauerbiene anhand des Expressionsmusters von zwei Uhrkomponenten. Diese sind das Uhrprotein PERIOD (PER) und das Neuropeptid Pigment Dispersing Factor (PDF). PER wird exprimiert in lateralen Neuronen-Gruppen (die wir laterale Neurone 1 und 2 nannten: LN1 und LN2) und dorsalen Neuronen-Gruppen (benannt dorsal laterale Neurone und dorsale Neurone: DLN und DN), sowie in vielen Gliazellen und Fotorezeptorzellen. Dieses Expressionsmuster liegt ähnlich in anderen Insektengruppen vor und deutet auf einen Grundbauplan der Inneren Uhr im Gehirn von Insekten hin. In der LN2 Neuronen-Gruppe, deren Zellkörper im lateralen Gehirn liegen, sind PER und PDF in den gleichen Zellen co-lokalisiert. Diese Zellen bilden ein komplexes Netzwerk aus Verzweigungen durch das gesamte Gehirn und liefern damit die perfekte Infrastruktur, um Zeitinformation an Gehirnregionen weiterzuleiten, die komplexe Verhaltensweisen, wie Sonnenkompass-Orientierung und Zeitgedächtnis, steuern. Alle PDF Neuriten laufen in einer anterior zur Lobula liegenden Region zusammen (sie wurde ALO, anterio-lobular PDF Knotenpunkt, genannt). Dieser Knotenpunkt ist in anderen Insekten mit der Medulla assoziiert und wird akzessorische Medulla (AME) genannt. Wenige PDF Zellen bilden bereits im frühen Larvalstadium diesen ALO und die Zellzahl sowie die Komplexität des Netzwerks wächst die gesamte Entwicklung der Honigbiene hindurch. Dabei werden zuerst die dorsalen Gehirnregionen von PDF Neuronen innerviert und in der späteren Larvalentwicklung wachsen die Neurite lateral in Richtung der optischen Loben und des Zentralgehirns. Das generelle Expressionsmuster von PER und PDF in adulten sozialen und solitären Bienen ähnelt sich stark, aber ich identifizierte kleine Unterschiede in der PDF Netzwerkdichte im posterioren Protocerebrum und in der Lamina. Diese könnten mit der Evolution von sozialen Bienen assoziiert sein. Zweitens entwickelte und etablierte ich eine Methode, Lokomotionsrhythmen von individuellen Bienen im Labor aufzunehmen, die in Kontakt mit einem Miniaturvolk standen. Diese Methode enthüllte neue Aspekte der sozialen Synchronisation unter Honigbienen und des Überlebens von jungen Bienen, die indirekten sozialen Kontakt zu dem Miniaturvolk hatten (Trophalaxis war nicht möglich). Für Mauerbienen etablierte ich eine Methode Schlupf- und lokomotorische Aktivitätsrhythmik aufzuzeichnen und konnte damit zeigen, dass tägliche Rhythmen im Schlupf durch Synchronisation der circadianen Uhr in Mauerbienen durch Tagestemperatur-Zyklen erzielt werden kann. Des Weiteren präsentiere ich die ersten lokomotorischen Aktivitätsrhythmen von solitären Bienen, die sofort nach ihrem Schlupf einen starken circadianen Rhythmus im Verhalten aufwiesen. Honigbienen brauchten in meinen Experimenten mehrere Tage, um circadiane Rhythmen in Lokomotion zu entwickeln. Ich erstellte die Hypothese, dass Honigbienen zum Zeitpunkt des Schlupfes im Bienenvolk ein noch nicht vollständig ausgereiftes circadianes System besitzen, während solitäre Bienen, die ohne den Schutz eines Volkes sind, direkt nach dem Schlupf eine vollständig ausgereifte Uhr brauchen. Mehrere Hinweise in Publikationen und Vorversuchen unterstützen meine Hypothese. Zukünftige Studien der Entwicklung des PDF Neuronen-Netzwerkes in solitären Bienen unterschiedlicher Entwicklungsstufen könnten dies nachweisen. KW - Chronobiologie KW - circadian rhythms KW - honeybee KW - Mauerbiene KW - Neuroanatomie Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159765 ER - TY - JOUR A1 - Beer, Katharina A1 - Joschinski, Jens A1 - Sastre, Alazne Arrazola A1 - Krauss, Jochen A1 - Helfrich-Förster, Charlotte T1 - A damping circadian clock drives weak oscillations in metabolism and locomotor activity of aphids (Acyrthosiphon pisum) JF - Scientific Reports N2 - Timing seasonal events, like reproduction or diapause, is crucial for the survival of many species. Global change causes phenologies worldwide to shift, which requires a mechanistic explanation of seasonal time measurement. Day length (photoperiod) is a reliable indicator of winter arrival, but it remains unclear how exactly species measure day length. A reference for time of day could be provided by a circadian clock, by an hourglass clock, or, as some newer models suggest, by a damped circadian clock. However, damping of clock outputs has so far been rarely observed. To study putative clock outputs of Acyrthosiphon pisum aphids, we raised individual nymphs on coloured artificial diet, and measured rhythms in metabolic activity in light-dark illumination cycles of 16:08 hours (LD) and constant conditions (DD). In addition, we kept individuals in a novel monitoring setup and measured locomotor activity. We found that A. pisum is day-active in LD, potentially with a bimodal distribution. In constant darkness rhythmicity of locomotor behaviour persisted in some individuals, but patterns were mostly complex with several predominant periods. Metabolic activity, on the other hand, damped quickly. A damped circadian clock, potentially driven by multiple oscillator populations, is the most likely explanation of our results. KW - circadian mechanisms KW - behavioural ecology KW - damped circadian clock KW - Acyrthosiphon pisum Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170020 VL - 7 IS - 14906 ER - TY - JOUR A1 - Beer, Katharina A1 - Steffan-Dewenter, Ingolf A1 - Härtel, Stephan A1 - Helfrich-Förster, Charlotte T1 - A new device for monitoring individual activity rhythms of honey bees reveals critical effects of the social environment on behavior JF - Journal of Comparative Physiology A N2 - Chronobiological studies of individual activity rhythms in social insects can be constrained by the artificial isolation of individuals from their social context. We present a new experimental set-up that simultaneously measures the temperature rhythm in a queen-less but brood raising mini colony and the walking activity rhythms of singly kept honey bees that have indirect social contact with it. Our approach enables monitoring of individual bees in the social context of a mini colony under controlled laboratory conditions. In a pilot experiment, we show that social contact with the mini colony improves the survival of monitored young individuals and affects locomotor activity patterns of young and old bees. When exposed to conflicting Zeitgebers consisting of a light-dark (LD) cycle that is phase-delayed with respect to the mini colony rhythm, rhythms of young and old bees are socially synchronized with the mini colony rhythm, whereas isolated bees synchronize to the LD cycle. We conclude that the social environment is a stronger Zeitgeber than the LD cycle and that our new experimental set-up is well suited for studying the mechanisms of social entrainment in honey bees. KW - Social entrainment KW - Foragers KW - Nurses KW - Locomotor activity KW - Temperature rhythms Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188030 VL - 202 IS - 8 ER - TY - JOUR A1 - Neubauer, Henning A1 - Wirth, Clemens A1 - Ruf, Katharina A1 - Hebestreit, Helge A1 - Beer, Meinrad T1 - Acute Muscle Trauma due to Overexercise in an Otherwise Healthy Patient with Cystic Fibrosis JF - Case Reports in Pediatrics N2 - Cystic fibrosis (CF) is one of the most common inherited diseases and is caused by mutations in the CFTR gene. Although the pulmonary and gastrointestinal manifestations of the disease remain in the focus of treatment, recent studies have shown expression of the CFTR gene product in skeletal muscle cells and observed altered intramuscular \(Ca^{2+}\) release dynamics in CFTR-deficient animal models. Physical exercise is beneficial for maintaining fitness and well-being in CF patients and constitutes one aspect of modern multimodal treatment, which has considerably increased life span and reduced morbidity. We report on a case of acute muscle trauma resulting from excessive dumbbell exercise in a young adult with cystic fibrosis and describe clinical, laboratory and imaging characteristics of acute exercise-induced muscle injury. KW - Cystic fibrosis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123967 VL - 2012 IS - 527989 ER - TY - JOUR A1 - Colizzi, Francesca Sara A1 - Beer, Katharina A1 - Cuti, Paolo A1 - Deppisch, Peter A1 - Martínez Torres, David A1 - Yoshii, Taishi A1 - Helfrich-Förster, Charlotte T1 - Antibodies Against the Clock Proteins Period and Cryptochrome Reveal the Neuronal Organization of the Circadian Clock in the Pea Aphid JF - Frontiers in Physiology N2 - Circadian clocks prepare the organism to cyclic environmental changes in light, temperature, or food availability. Here, we characterized the master clock in the brain of a strongly photoperiodic insect, the aphid Acyrthosiphon pisum, immunohistochemically with antibodies against A. pisum Period (PER), Drosophila melanogaster Cryptochrome (CRY1), and crab Pigment-Dispersing Hormone (PDH). The latter antibody detects all so far known PDHs and PDFs (Pigment-Dispersing Factors), which play a dominant role in the circadian system of many arthropods. We found that, under long days, PER and CRY are expressed in a rhythmic manner in three regions of the brain: the dorsal and lateral protocerebrum and the lamina. No staining was detected with anti-PDH, suggesting that aphids lack PDF. All the CRY1-positive cells co-expressed PER and showed daily PER/CRY1 oscillations of high amplitude, while the PER oscillations of the CRY1-negative PER neurons were of considerable lower amplitude. The CRY1 oscillations were highly synchronous in all neurons, suggesting that aphid CRY1, similarly to Drosophila CRY1, is light sensitive and its oscillations are synchronized by light-dark cycles. Nevertheless, in contrast to Drosophila CRY1, aphid CRY1 was not degraded by light, but steadily increased during the day and decreased during the night. PER was always located in the nuclei of the clock neurons, while CRY was predominantly cytoplasmic and revealed the projections of the PER/CRY1-positive neurons. We traced the PER/CRY1-positive neurons through the aphid protocerebrum discovering striking similarities with the circadian clock of D. melanogaster: The CRY1 fibers innervate the dorsal and lateral protocerebrum and putatively connect the different PER-positive neurons with each other. They also run toward the pars intercerebralis, which controls hormone release via the neurohemal organ, the corpora cardiaca. In contrast to Drosophila, the CRY1-positive fibers additionally travel directly toward the corpora cardiaca and the close-by endocrine gland, corpora allata. This suggests a direct link between the circadian clock and the photoperiodic control of hormone release that can be studied in the future. KW - aphids KW - circadian clock KW - cryptochrome KW - period KW - hemiptera KW - insects KW - photoperiodism Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-242909 SN - 1664-042X VL - 12 ER - TY - THES A1 - Beer, Katharina Beate T1 - Identification and characterization of TAT-5 interactors that regulate extracellular vesicle budding T1 - Identifizierung und Charakterisierung von TAT-5 Interaktoren, welche die Ausschüttung von Extrazellulären Vesikeln regulieren N2 - Cells from bacteria to man release extracellular vesicles (EV) such as microvesicles (MV) that carry signaling molecules like morphogens and miRNAs to control intercellular communication during health and disease. MV release also sculpts membranes, e.g. repairing damaged membranes to avoid cell death. HIV viruses also bud from the plasma membrane in a similar fashion. In order to determine the in vivo functions of MVs and regulate their release, we need to understand the mechanisms of MV release by plasma membrane budding (ectocytosis). The conserved phospholipid flippase TAT-5 maintains the asymmetric localization of phosphatidylethanolamine (PE) in the plasma membrane and was the only known inhibitor of ESCRT-mediated ectocytosis in C. elegans. Loss of TAT-5 lipid flipping activity increased the externalization of PE and accumulation of MVs. However, it was unclear how cells control TAT-5 activity to release the right amount of MVs at the right time, since no upstream regulators of TAT-5 were known. To identify conserved TAT-5 regulators we looked for new proteins that inhibit MV release. To do so, we first developed a degradation-based technique to specifically label MVs. We tagged a plasma membrane reporter with the endogenous ZF1 degradation tag (degron) and expressed it in C. elegans embryos. This reporter is protected from degradation inside MVs, but is degraded inside the cell. Thus, the fluorescence is selectively maintained inside MVs, creating the first MV-specific reporter. We identified four MV release inhibitors associated with retrograde recycling, including the class III PI3Kinase VPS-34, Beclin1 homolog BEC-1, DnaJ protein RME-8, and the uncharacterized Dopey homolog PAD-1. We found that VPS-34, BEC-1, RME-8, and redundant sorting nexins are required for the plasma membrane localization of TAT-5, which is important to maintain PE asymmetry and inhibit MV release. Although we confirmed that PAD-1 and the GEF-like protein MON-2 are required for endosomal recycling, they only traffic TAT-5 in the absence of sorting nexin-mediated recycling. Instead, PAD-1 is specifically required for the lipid flipping activity of TAT-5 that inhibits MV release. Thus, our work pinpoints TAT-5 and PE as key regulators of plasma membrane budding, further supporting the model that PE externalization drives ectocytosis. In addition, we uncovered redundant intracellular trafficking pathways, which affect organelle size and revealed new regulators of TAT-5 flippase activity. These newly identified ectocytosis inhibitors provide a toolkit to test the in vivo roles of MVs. In the long term, our work will help to identify the mechanisms that govern MV budding, furthering our understanding of the mechanisms that regulate disease-mediated EV release, membrane sculpting and viral budding. N2 - Zellen von Bakterien bis zum Menschen produzieren Extrazelluläre Vesikel (EV) wie zum Beispiel Mikrovesikel (MV). MV können Signal Moleküle wie Morphogene und miRNA transportieren, welche die normale oder krankheitsbedingte interzelluläre Kommunikation kontrollieren. Bei der Produktion von MVs werden Membranen verformt, wie auch für die Reparatur von beschädigten Membranen um den Zelltod zu verhindern. Außerdem knospen HIV-Virus Partikel von der Plasma Membrane durch eine ähnliche Art und Weise. Um zu verstehen welche in vivo Funktion MV haben, müssen wir die Mechanismen der MV Knospung von der Plasma Membran (Ektozytose) verstehen. Die konservierte Phospholipid Flippase TAT-5 hält die asymmetrische Verteilung von Phosphatidylethanolamine (PE) in der Plasma Membrane aufrecht und war der einzig bekannte Inhibitor der von ESCRT Proteinen durchgeführten Ektozytose in C. elegans. Wenn die Lipid-flippende Funktion von TAT-5 verloren geht, wird PE externalisiert und MV sammeln sich außerhalb der Zelle an. Allerdings ist es unklar mit welchen Mechanismen die Aktivität von TAT-5 reguliert wird um die richtige Menge an MV zur richtigen Zeit zu produzieren, da die vorgeschalteten Regulatoren unbekannt sind. Um konservierte TAT-5 Regulatoren zu identifizieren suchten wir nach neuen Proteinen, die die Produktion von MV inhibieren. Dazu entwickelten wir eine Degradations-Technik um MV spezifisch zu kennzeichnen. Wir markierten einen fluoreszierenden Plasma Membran Marker mit dem endogenen ZF1 Degradations-Kennzeichen (Degron) und exprimierten es im C. elegans Embryo. Der Marker wird vor der Degradation geschützt, wenn er in einem MV von der Zelle ausgesondert wurde. Dadurch bleibt die Fluoreszenz speziell in MV erhalten, während sie innerhalb der Zelle abgebaut wird. Dadurch wurde die Sichtbarkeit von ausgeschütteten MV erhöht. Wir fanden vier Proteine, welche mit Protein Recycling in Verbindung gebracht werden, die die Ausschüttung von MV verhindern: Class III PI3Kiase VPS-34, Beclin1 Homolog BEC-1, DnaJ Protein RME-8 und das nicht näher charakterisierte Dopey Homolog PAD-1. Wir benutzten dieses Set an Proteinen, um zu testen ob und wie diese TAT-5 regulieren können. Wir fanden, dass Class III PI3Kinase, RME-8 und redundante Sorting Nexins für die Plasma Membran Lokalisierung von TAT-5 verantwortlich sind, was wichtig ist um die PE Asymmetrie aufrecht zu erhalten und die MV Produktion zu verhindern. Wenn auch PAD-1 und das GEF-ähnliche MON-2 für endosomales Recycling verantwortlich sind, regulieren sie die Lokalisation von TAT-5 nur in Abwesenheit von Sorting Nexins-reguliertem Transport. Zudem scheint PAD-1 direkt für die Lipid Translokations-Aktivität von TAT-5 verantwortlich zu sein. Demnach konnten wir zeigen, dass TAT-5 und PE Schlüsselregulatoren für MV Produktion sind, was weiterhin die Ansicht unterstützt, dass PE Externalisierung für die Ektozytose verantwortlich ist. Außerdem fanden wir, dass redundante intrazelluläre Transportwege für die Größe von Organellen verantwortlich sind und deckten neue TAT-5 Aktivitäts-Regulatoren auf. Diese neu aufgedeckten Ektozytose Inhibitoren könnten Werkzeuge sein um die in vivo Funktionen von MV zu testen. Längerfristig kann unsere Forschung dazu beitragen die Mechanismen der MV Produktion zu identifizieren und die Regulation während der krankheitsbedingten EV Produktion, der Membrane Reparatur und der Virus Knospung besser zu verstehen. KW - C. elegans KW - Extracellular Vesicles KW - Microvesicle KW - Flippase KW - P4-ATPase KW - Caenorhabditis elegans KW - Vesikelbildung Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-206724 ER - TY - JOUR A1 - Philipp-Abbrederis, Kathrin A1 - Herrmann, Ken A1 - Knop, Stefan A1 - Schottelius, Margret A1 - Eiber, Matthias A1 - Lückerath, Katharina A1 - Pietschmann, Elke A1 - Habringer, Stefan A1 - Gerngroß, Carlos A1 - Franke, Katharina A1 - Rudelius, Martina A1 - Schirbel, Andreas A1 - Lapa, Constantin A1 - Schwamborn, Kristina A1 - Steidle, Sabine A1 - Hartmann, Elena A1 - Rosenwald, Andreas A1 - Kropf, Saskia A1 - Beer, Ambros J A1 - Peschel, Christian A1 - Einsele, Hermann A1 - Buck, Andreas K A1 - Schwaiger, Markus A1 - Götze, Katharina A1 - Wester, Hans-Jürgen A1 - Keller, Ulrich T1 - In vivo molecular imaging of chemokine receptor CXCR4 expression in patients with advanced multiple myeloma JF - EMBO Molecular Medicine N2 - CXCR4 is a G-protein-coupled receptor that mediates recruitment of blood cells toward its ligand SDF-1. In cancer, high CXCR4 expression is frequently associated with tumor dissemination andpoor prognosis. We evaluated the novel CXCR4 probe [\(^{68}\)Ga]Pentixafor for invivo mapping of CXCR4 expression density in mice xenografted with human CXCR4-positive MM cell lines and patients with advanced MM by means of positron emission tomography (PET). [\(^{68}\)Ga]Pentixafor PET provided images with excellent specificity and contrast. In 10 of 14 patients with advanced MM [\(^{68}\)Ga]Pentixafor PET/CT scans revealed MM manifestations, whereas only nine of 14 standard [\(^{18}\)F]fluorodeoxyglucose PET/CT scans were rated visually positive. Assessment of blood counts and standard CD34\(^{+}\) flow cytometry did not reveal significant blood count changes associated with tracer application. Based on these highly encouraging data on clinical PET imaging of CXCR4 expression in a cohort of MM patients, we conclude that [\(^{68}\)Ga]Pentixafor PET opens a broad field for clinical investigations on CXCR4 expression and for CXCR4-directed therapeutic approaches in MM and other diseases. KW - FDG PET/CT KW - cells KW - CXCR4/SDF-1 KW - CXCR4 KW - multiple myeloma KW - positron emission tomography KW - chemokine receptor KW - in vivo imaging KW - malignancies KW - involvement KW - microenvironment KW - survival KW - cancer KW - autologous transplantation KW - bone disease Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148738 VL - 7 IS - 4 ER - TY - JOUR A1 - Heise, Ruth A1 - Amann, Philipp M. A1 - Ensslen, Silke A1 - Marquardt, Yvonne A1 - Czaja, Katharina A1 - Joussen, Sylvia A1 - Beer, Daniel A1 - Abele, Rupert A1 - Plewnia, Gabriele A1 - Tampé, Robert A1 - Merk, Hans F. A1 - Hermanns, Heike M. A1 - Baron, Jens M. T1 - Interferon Alpha Signalling and Its Relevance for the Upregulatory Effect of Transporter Proteins Associated with Antigen Processing (TAP) in Patients with Malignant Melanoma JF - PLoS ONE N2 - Introduction Interferon alpha (IFNα) is routinely used in the clinical practice for adjuvant systemic melanoma therapy. Understanding the molecular mechanism of IFNα effects and prediction of response in the IFNα therapy regime allows initiation and continuation of IFNα treatment for responder and exclusion of non-responder to avoid therapy inefficacy and side-effects. The transporter protein associated with antigen processing-1 (TAP1) is part of the MHC class I peptide-loading complex, and important for antigen presentation in tumor and antigen presenting cells. In the context of personalized medicine, we address this potential biomarker TAP1 as a target of IFNα signalling. Results We could show that IFNα upregulates TAP1 expression in peripheral blood mononuclear cells (PBMCs) of patients with malignant melanoma receiving adjuvant high-dose immunotherapy. IFNα also induced expression of TAP1 in mouse blood and tumor tissue and suppressed the formation of melanoma metastasis in an in vivo B16 tumor model. Besides its expression, TAP binding affinity and transport activity is induced by IFNα in human monocytic THP1 cells. Furthermore, our data revealed that IFNα clearly activates phosphorylation of STAT1 and STAT3 in THP1 and A375 melanoma cells. Inhibition of Janus kinases abrogates the IFNα-induced TAP1 expression. These results suggest that the JAK/STAT pathway is a crucial mediator for TAP1 expression elicited by IFNα treatment. Conclusion We suppose that silencing of TAP1 expression provides tumor cells with a mechanism to escape cytotoxic T-lymphocyte recognition. The observed benefit of IFNα treatment could be mediated by the shown dual effect of TAP1 upregulation in antigen presenting cells on the one hand, and of TAP1 upregulation in ‘silent’ metastatic melanoma cells on the other hand. In conclusion, this work contributes to a better understanding of the mode of action of IFNα which is essential to identify markers to predict, assess and monitor therapeutic response of IFNα treatment in the future. KW - interferon alpha signalling KW - interferon alpha (IFNα) KW - transporter protein associated with antigen processing-1 (TAP1) KW - melanoma therapy Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167409 VL - 11 IS - 1 ER - TY - JOUR A1 - Fazeli, Gholamreza A1 - Beer, Katharina B. A1 - Geisenhof, Michaela A1 - Tröger, Sarah A1 - König, Julia A1 - Müller-Reichert, Thomas A1 - Wehman, Ann M. T1 - Loss of the Major Phosphatidylserine or Phosphatidylethanolamine Flippases Differentially Affect Phagocytosis JF - Frontiers in Cell and Developmental Biology N2 - The lipids phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEth) are normally asymmetrically localized to the cytosolic face of membrane bilayers, but can both be externalized during diverse biological processes, including cell division, cell fusion, and cell death. Externalized lipids in the plasma membrane are recognized by lipid-binding proteins to regulate the clearance of cell corpses and other cell debris. However, it is unclear whether PtdSer and PtdEth contribute in similar or distinct ways to these processes. We discovered that disruption of the lipid flippases that maintain PtdSer or PtdEth asymmetry in the plasma membrane have opposite effects on phagocytosis in Caenorhabditis elegans embryos. Constitutive PtdSer externalization caused by disruption of the major PtdSer flippase TAT-1 led to increased phagocytosis of cell debris, sometimes leading to two cells engulfing the same debris. In contrast, PtdEth externalization caused by depletion of the major PtdEth flippase TAT-5 or its activator PAD-1 disrupted phagocytosis. These data suggest that PtdSer and PtdEth externalization have opposite effects on phagocytosis. Furthermore, externalizing PtdEth is associated with increased extracellular vesicle release, and we present evidence that the extent of extracellular vesicle accumulation correlates with the extent of phagocytic defects. Thus, a general loss of lipid asymmetry can have opposing impacts through different lipid subtypes simultaneously exerting disparate effects. KW - phagocytosis KW - lipid asymmetry KW - flippase KW - phosphatidylserine KW - phosphatidylethanolamine KW - extracellular vesicle Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-208771 SN - 2296-634X VL - 8 ER - TY - JOUR A1 - Beer, Katharina A1 - Helfrich-Förster, Charlotte T1 - Model and Non-model Insects in Chronobiology JF - Frontiers in Behavioral Neuroscience N2 - The fruit fly Drosophila melanogaster is an established model organism in chronobiology, because genetic manipulation and breeding in the laboratory are easy. The circadian clock neuroanatomy in D. melanogaster is one of the best-known clock networks in insects and basic circadian behavior has been characterized in detail in this insect. Another model in chronobiology is the honey bee Apis mellifera, of which diurnal foraging behavior has been described already in the early twentieth century. A. mellifera hallmarks the research on the interplay between the clock and sociality and complex behaviors like sun compass navigation and time-place-learning. Nevertheless, there are aspects of clock structure and function, like for example the role of the clock in photoperiodism and diapause, which can be only insufficiently investigated in these two models. Unlike high-latitude flies such as Chymomyza costata or D. ezoana, cosmopolitan D. melanogaster flies do not display a photoperiodic diapause. Similarly, A. mellifera bees do not go into “real” diapause, but most solitary bee species exhibit an obligatory diapause. Furthermore, sociality evolved in different Hymenoptera independently, wherefore it might be misleading to study the social clock only in one social insect. Consequently, additional research on non-model insects is required to understand the circadian clock in Diptera and Hymenoptera. In this review, we introduce the two chronobiology model insects D. melanogaster and A. mellifera, compare them with other insects and show their advantages and limitations as general models for insect circadian clocks. KW - circadian clock KW - complex behavior KW - diapause KW - sociality KW - Drosophila melanogaster KW - Apis mellifera Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218721 SN - 1662-5153 VL - 14 ER - TY - JOUR A1 - Joschinski, Jens A1 - Beer, Katharina A1 - Helfrich-Förster, Charlotte A1 - Krauss, Jochen T1 - Pea Aphids (Hemiptera: Aphididae) Have Diurnal Rhythms When Raised Independently of a Host Plant JF - Journal of Insect Science N2 - Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids. For instance, it is unknown whether aphids possess diurnal rhythms at all. Possibly, the close interaction with host plants prevents independent measurements of rhythmicity. We reared the pea aphid Acyrthosiphon pisum (Harris) on an artificial diet, and recorded survival, moulting, and honeydew excretion. Despite their plant-dependent life style, aphids were independently rhythmic under light–dark conditions. This first demonstration of diurnal aphid rhythms shows that aphids do not simply track the host plant’s rhythmicity. KW - artificial diet KW - circadian clock KW - hourglass clock KW - Acyrthosiphon pisum KW - photoperiodism Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168783 VL - 16 IS - 1 ER - TY - JOUR A1 - Beer, Katharina A1 - Helfrich-Förster, Charlotte T1 - Post-embryonic Development of the Circadian Clock Seems to Correlate With Social Life Style in Bees JF - Frontiers in Cell and Developmental Biology N2 - Social life style can influence many aspects of an animal’s daily life, but it has not yet been clarified, whether development of the circadian clock in social and solitary living bees differs. In a comparative study, with the social honey bee, Apis mellifera, and the solitary mason bee, Osmia bicornis, we now found indications for a differentially timed clock development in social and solitary bees. Newly emerged solitary bees showed rhythmic locomotion right away and the number of neurons in the brain that produce the clock component pigment-dispersing factor (PDF) did not change during aging of the adult solitary bee. Honey bees on the other hand, showed no circadian locomotion directly after emergence and the neuronal clock network continued to grow after emergence. Social bees appear to emerge at an early developmental stage at which the circadian clock is still immature, but bees are already able to fulfill in-hive tasks. KW - social KW - honey bee KW - solitary bee KW - circadian clock KW - activity rhythm KW - neuronal network KW - development Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-216450 SN - 2296-634X VL - 8 ER - TY - JOUR A1 - Ruf, Katharina A1 - Beer, Meinrad A1 - Köstler, Herbert A1 - Weng, Andreas Max A1 - Neubauer, Henning A1 - Klein, Alexander A1 - Platek, Kathleen A1 - Roth, Kristina A1 - Beneke, Ralph A1 - Hebestreit, Helge T1 - Size-adjusted muscle power and muscle metabolism in patients with cystic fibrosis are equal to healthy controls – a case control study JF - BMC Pulmonary Medicine N2 - Background Skeletal muscle function dysfunction has been reported in patients with cystic fibrosis (CF). Studies so far showed inconclusive data whether reduced exercise capacity is related to intrinsic muscle dysfunction in CF. Methods Twenty patients with CF and 23 age-matched controls completed an incremental cardiopulmonary cycling test. Further, a Wingate anaerobic test to assess muscle power was performed. In addition, all participants completed an incremental knee-extension test with 31P magnetic resonance spectroscopy to assess muscle metabolism (inorganic phosphate (Pi) and phosphocreatinine (PCr) as well as intracellular pH). In the MRI, muscle cross-sectional area of the M. quadriceps (qCSA) was also measured. A subgroup of 15 participants (5 CF, 10 control) additionally completed a continuous high-intensity, high-frequency knee-extension exercise task during 31P magnetic resonance spectroscopy to assess muscle metabolism. Results Patients with CF showed a reduced exercise capacity in the incremental cardiopulmonary cycling test (VO2peak: CF 77.8 ± 16.2%predicted (36.5 ± 7.4 ml/qCSA/min), control 100.6 ± 18.8%predicted (49.1 ± 11.4 ml/qCSA/min); p < 0.001), and deficits in anaerobic capacity reflected by the Wingate test (peak power: CF 537 ± 180 W, control 727 ± 186 W; mean power: CF 378 ± 127 W, control 486 ± 126 W; power drop CF 12 ± 5 W, control 8 ± 4 W. all: p < 0.001). In the knee-extension task, patients with CF achieved a significantly lower workload (p < 0.05). However, in a linear model analysing maximal work load of the incremental knee-extension task and results of the Wingate test, respectively, only muscle size and height, but not disease status (CF or not) contributed to explaining variance. In line with this finding, no differences were found in muscle metabolism reflected by intracellular pH and the ratio of Pi/PCr at submaximal stages and peak exercise measured through MRI spectroscopy. Conclusions The lower absolute muscle power in patients with CF compared to controls is exclusively explained by the reduced muscle size in this study. No evidence was found for an intrinsic skeletal muscle dysfunction due to primary alterations of muscle metabolism. KW - Cystic fibrosis KW - Exercise capacity KW - MRI spectroscopy KW - Muscle power KW - Phosphorylation KW - Lung disease, KW - Muscle function Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200981 VL - 19 ER - TY - JOUR A1 - Beer, Katharina A1 - Schenk, Mariela A1 - Helfrich-Förster, Charlotte A1 - Holzschuh, Andrea T1 - The circadian clock uses different environmental time cues to synchronize emergence and locomotion of the solitary bee Osmia bicornis JF - Scientific Reports N2 - Life on earth adapted to the daily reoccurring changes in environment by evolving an endogenous circadian clock. Although the circadian clock has a crucial impact on survival and behavior of solitary bees, many aspects of solitary bee clock mechanisms remain unknown. Our study is the first to show that the circadian clock governs emergence in Osmia bicornis, a bee species which overwinters as adult inside its cocoon. Therefore, its eclosion from the pupal case is separated by an interjacent diapause from its emergence in spring. We show that this bee species synchronizes its emergence to the morning. The daily rhythms of emergence are triggered by temperature cycles but not by light cycles. In contrast to this, the bee’s daily rhythms in locomotion are synchronized by light cycles. Thus, we show that the circadian clock of O. bicornis is set by either temperature or light, depending on what activity is timed. Light is a valuable cue for setting the circadian clock when bees have left the nest. However, for pre-emerged bees, temperature is the most important cue, which may represent an evolutionary adaptation of the circadian system to the cavity-nesting life style of O. bicornis. KW - Behavioural ecology KW - Evolutionary developmental biology Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202721 VL - 9 ER - TY - JOUR A1 - Beer, Katharina A1 - Härtel, Stephan A1 - Helfrich-Förster, Charlotte T1 - The pigment-dispersing factor neuronal network systematically grows in developing honey bees JF - The Journal of Comparative Neurology N2 - The neuropeptide pigment-dispersing factor (PDF) plays a prominent role in the circadian clock of many insects including honey bees. In the honey bee brain, PDF is expressed in about 15 clock neurons per hemisphere that lie between the central brain and the optic lobes. As in other insects, the bee PDF neurons form wide arborizations in the brain, but certain differences are evident. For example, they arborize only sparsely in the accessory medulla (AME), which serves as important communication center of the circadian clock in cockroaches and flies. Furthermore, all bee PDF neurons cluster together, which makes it impossible to distinguish individual projections. Here, we investigated the developing bee PDF network and found that the first three PDF neurons arise in the third larval instar and form a dense network of varicose fibers at the base of the developing medulla that strongly resembles the AME of hemimetabolous insects. In addition, they send faint fibers toward the lateral superior protocerebrum. In last larval instar, PDF cells with larger somata appear and send fibers toward the distal medulla and the medial protocerebrum. In the dorsal part of the medulla serpentine layer, a small PDF knot evolves from which PDF fibers extend ventrally. This knot disappears during metamorphosis and the varicose arborizations in the putative AME become fainter. Instead, a new strongly stained PDF fiber hub appears in front of the lobula. Simultaneously, the number of PDF neurons increases and the PDF neuronal network in the brain gets continuously more complex. KW - apis mellifera KW - circadian clock KW - immunohistochemistry KW - larval and pupal development KW - neuroanatomy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257300 VL - 530 IS - 9 ER -