@article{AmatobiOzbekUnalSchaebleretal.2023, author = {Amatobi, Kelechi M. and Ozbek-Unal, Ayten Gizem and Sch{\"a}bler, Stefan and Deppisch, Peter and Helfrich-F{\"o}rster, Charlotte and Mueller, Martin J. and Wegener, Christian and Fekete, Agnes}, title = {The circadian clock is required for rhythmic lipid transport in Drosophila in interaction with diet and photic condition}, series = {Journal of Lipid Research}, volume = {64}, journal = {Journal of Lipid Research}, number = {10}, doi = {10.1016/j.jlr.2023.100417}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-349961}, pages = {100417}, year = {2023}, abstract = {Modern lifestyle is often at odds with endogenously driven rhythmicity, which can lead to circadian disruption and metabolic syndrome. One signature for circadian disruption is a reduced or altered metabolite cycling in the circulating tissue reflecting the current metabolic status. Drosophila is a well-established model in chronobiology, but day-time dependent variations of transport metabolites in the fly circulation are poorly characterized. Here, we sampled fly hemolymph throughout the day and analyzed diacylglycerols (DGs), phosphoethanolamines (PEs) and phosphocholines (PCs) using LC-MS. In wild-type flies kept on sugar-only medium under a light-dark cycle, all transport lipid species showed a synchronized bimodal oscillation pattern with maxima at the beginning and end of the light phase which were impaired in period01 clock mutants. In wild-type flies under constant dark conditions, the oscillation became monophasic with a maximum in the middle of the subjective day. In strong support of clock-driven oscillations, levels of the targeted lipids peaked once in the middle of the light phase under time-restricted feeding independent of the time of food intake. When wild-type flies were reared on full standard medium, the rhythmic alterations of hemolymph lipid levels were greatly attenuated. Our data suggest that the circadian clock aligns daily oscillations of DGs, PEs, and PCs in the hemolymph to the anabolic siesta phase, with a strong influence of light on phase and modality.}, language = {en} } @article{FujiwaraHermannLuiblKatsuraetal.2018, author = {Fujiwara, Yuri and Hermann-Luibl, Christiane and Katsura, Maki and Sekiguchi, Manabu and Ida, Takanori and Helfrich-F{\"o}rster, Charlotte and Yoshii, Taishi}, title = {The CCHamide1 Neuropeptide Expressed in the Anterior Dorsal Neuron 1 Conveys a Circadian Signal to the Ventral Lateral Neurons in Drosophila melanogaster}, series = {Frontiers in Physiology}, volume = {09}, journal = {Frontiers in Physiology}, issn = {1664-042X}, doi = {10.3389/fphys.2018.01276}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-195940}, year = {2018}, abstract = {The fruit fly Drosophila melanogaster possesses approximately 150 brain clock neurons that control circadian behavioral rhythms. Even though individual clock neurons have self-sustaining oscillators, they interact and synchronize with each other through a network. However, little is known regarding the factors responsible for these network interactions. In this study, we investigated the role of CCHamide1 (CCHa1), a neuropeptide expressed in the anterior dorsal neuron 1 (DN1a), in intercellular communication of the clock neurons. We observed that CCHa1 connects the DN1a clock neurons to the ventral lateral clock neurons (LNv) via the CCHa1 receptor, which is a homolog of the gastrin-releasing peptide receptor playing a role in circadian intercellular communications in mammals. CCHa1 knockout or knockdown flies have a generally low activity level with a special reduction of morning activity. In addition, they exhibit advanced morning activity under light-dark cycles and delayed activity under constant dark conditions, which correlates with an advance/delay of PAR domain Protein 1 (PDP1) oscillations in the small-LNv (s-LNv) neurons that control morning activity. The terminals of the s-LNv neurons show rather high levels of Pigment-dispersing factor (PDF) in the evening, when PDF is low in control flies, suggesting that the knockdown of CCHa1 leads to increased PDF release; PDF signals the other clock neurons and evidently increases the amplitude of their PDP1 cycling. A previous study showed that high-amplitude PDP1 cycling increases the siesta of the flies, and indeed, CCHa1 knockout or knockdown flies exhibit a longer siesta than control flies. The DN1a neurons are known to be receptive to PDF signaling from the s-LNv neurons; thus, our results suggest that the DN1a and s-LNv clock neurons are reciprocally coupled via the neuropeptides CCHa1 and PDF, and this interaction fine-tunes the timing of activity and sleep.}, language = {en} } @article{GrubisicHaimBhusaletal.2019, author = {Grubisic, Maja and Haim, Abraham and Bhusal, Pramod and Dominoni, Davide M. and Gabriel, Katharina M. A. and Jechow, Andreas and Kupprat, Franziska and Lerner, Amit and Marchant, Paul and Riley, William and Stebelova, Katarina and van Grunsven, Roy H. A. and Zeman, Michal and Zubidat, Abed E. and H{\"o}lker, Franz}, title = {Light Pollution, Circadian Photoreception, and Melatonin in Vertebrates}, series = {Sustainability}, volume = {11}, journal = {Sustainability}, number = {22}, issn = {2071-1050}, doi = {10.3390/su11226400}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193095}, year = {2019}, abstract = {Artificial light at night (ALAN) is increasing exponentially worldwide, accelerated by the transition to new efficient lighting technologies. However, ALAN and resulting light pollution can cause unintended physiological consequences. In vertebrates, production of melatonin—the "hormone of darkness" and a key player in circadian regulation—can be suppressed by ALAN. In this paper, we provide an overview of research on melatonin and ALAN in vertebrates. We discuss how ALAN disrupts natural photic environments, its effect on melatonin and circadian rhythms, and different photoreceptor systems across vertebrate taxa. We then present the results of a systematic review in which we identified studies on melatonin under typical light-polluted conditions in fishes, amphibians, reptiles, birds, and mammals, including humans. Melatonin is suppressed by extremely low light intensities in many vertebrates, ranging from 0.01-0.03 lx for fishes and rodents to 6 lx for sensitive humans. Even lower, wavelength-dependent intensities are implied by some studies and require rigorous testing in ecological contexts. In many studies, melatonin suppression occurs at the minimum light levels tested, and, in better-studied groups, melatonin suppression is reported to occur at lower light levels. We identify major research gaps and conclude that, for most groups, crucial information is lacking. No studies were identified for amphibians and reptiles and long-term impacts of low-level ALAN exposure are unknown. Given the high sensitivity of vertebrate melatonin production to ALAN and the paucity of available information, it is crucial to research impacts of ALAN further in order to inform effective mitigation strategies for human health and the wellbeing and fitness of vertebrates in natural ecosystems.}, language = {en} } @article{ChtourouEngelFakhfakhetal.2018, author = {Chtourou, Hamdi and Engel, Florian Azad and Fakhfakh, Hassen and Fakhfakh, Hazem and Hammouda, Omar and Ammar, Achraf and Trabelsi, Khaled and Souissi, Nizar and Sperlich, Billy}, title = {Diurnal Variation of Short-Term Repetitive Maximal Performance and Psychological Variables in Elite Judo Athletes}, series = {Frontiers in Physiology}, volume = {9}, journal = {Frontiers in Physiology}, issn = {1664-042X}, doi = {10.3389/fphys.2018.01499}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189269}, pages = {1409}, year = {2018}, abstract = {Objectives: The aim of this study was to examine the effect of time of day on short-term repetitive maximal performance and psychological variables in elite judo athletes. Methods: Fourteen Tunisian elite male judokas (age: 21 ± 1 years, height:172 ± 7 cm, body-mass: 70.0 ± 8.1 kg) performed a repeated shuttle sprint and jump ability (RSSJA) test (6 m × 2 m × 12.5 m every 25-s incorporating one countermovement jump (CMJ) between sprints) in the morning (7:00 a.m.) and afternoon (5:00 p.m.). Psychological variables (Profile of mood states (POMS-f) and Hooper questionnaires) were assessed before and ratings of perceived exertion (RPE) immediately after the RSSJA. Results: Sprint times (p > 0.05) of the six repetition, fatigue index of sprints (p > 0.05) as well as mean (p > 0.05) jump height and fatigue index (p > 0.05) of CMJ did not differ between morning and afternoon. No differences were observed between the two times-of-day for anxiety, anger, confusion, depression, fatigue, interpersonal relationship, sleep, and muscle soreness (p > 0.05). Jump height in CMJ 3 and 4 (p < 0.05) and RPE (p < 0.05) and vigor (p < 0.01) scores were higher in the afternoon compared to the morning. Stress was higher in the morning compared to the afternoon (p < 0.01). Conclusion: In contrast to previous research, repeated sprint running performance and mood states of the tested elite athletes showed no-strong dependency of time-of-day of testing. A possible explanation can be the habituation of the judo athletes to work out early in the morning.}, language = {en} } @article{BornZinnerSperlich2017, author = {Born, Dennis-Peter and Zinner, Christoph and Sperlich, Billy}, title = {The mucosal immune function is not compromised during a period of high-intensity interval training. Is it time to reconsider an old assumption?}, series = {Frontiers in Physiology}, volume = {8}, journal = {Frontiers in Physiology}, number = {485}, doi = {10.3389/fphys.2017.00485}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158025}, year = {2017}, abstract = {Purpose: The aim of the study was to evaluate the mucosal immune function and circadian variation of salivary cortisol, Immunoglobin-A (sIgA) secretion rate and mood during a period of high-intensity interval training (HIIT) compared to long-slow distance training (LSD). Methods: Recreational male runners (n = 28) completed nine sessions of either HIIT or LSD within 3 weeks. The HIIT involved 4 × 4 min of running at 90-95\% of maximum heart rate interspersed with 3 min of active recovery while the LSD comprised of continuous running at 70-75\% of maximum heart rate for 60-80 min. The psycho-immunological stress-response was investigated with a full daily profile of salivary cortisol and immunoglobin-A (sIgA) secretion rate along with the mood state on a baseline day, the first and last day of training and at follow-up 4 days after the last day of training. Before and after the training period, each athlete's running performance and peak oxygen uptake (V·O\(_{2peak}\)) was determined with an incremental exercise test. Results: The HIIT resulted in a longer time-to-exhaustion (P = 0.02) and increased V·O\(_{2peak}\) compared to LSD (P = 0.01). The circadian variation of sIgA secretion rate showed highest values in the morning immediately after waking up followed by a decrease throughout the day in both groups (P < 0.05). With HIIT, the wake-up response of sIgA secretion rate was higher on the last day of training (P < 0.01) as well as the area under the curve (AUC\(_{G}\)) higher on the first and last day of training and follow-up compared to the LSD (P = 0.01). Also the AUC\(_{G}\) for the sIgA secretion rate correlated with the increase in V·O\(_{2peak}\) and running performance. The AUC\(_{G}\) for cortisol remained unaffected on the first and last day of training but increased on the follow-up day with both, HIIT and LSD (P < 0.01). Conclusion: The increased sIgA secretion rate with the HIIT indicates no compromised mucosal immune function compared to LSD and shows the functional adaptation of the mucosal immune system in response to the increased stress and training load of nine sessions of HIIT.}, language = {en} }