239 research outputs found
Development of a system to measure cardiac function in the drosophila melanogaster animal model
Previous studies have shown that several genes are evolutionarily conserved from lower organisms to man, where a number of genes have been directly linked to cardiac function and disease. The Drosophila melanogaster (Fruit Fly) has a genome similar to humans and therefore has proven to be an important animal model to study the role of genetics in cardiac function and disease development. Fruit flies are an important basic science model because of the ease with which genes can be manipulated and quickly expressed due to the short lifespan of the fly. Although standard techniques exist to affect the genome of the fly, measurement of fly cardiac function is not well established due to technical difficulties stemming from the fly size and fragility. This work describes a system developed to measure in vivo cardiac function of an adult Fruit Fly. This involved design of a novel anesthesia chamber to accurately anesthetize fruit flies, construction of a microscope-image analysis system to visualize the fruit fly heart beating in real time, implementation of an image analysis method to analyze fruit fly heart rate, and design and implementation of an electrical pacing system to stress the fruit fly heart. This system was tested with standard yellow white (yw) fruit flies. Data obtained confirmed previous studies showing that aging affects fruit fly heart rate (9 day: 285.2 ± 5.8 bpm, 30 day: 221.7 ± 8.1 bpm, 53 day: 195.1 ± 9 bpm) and ability to handle pacing stress. This study determined that a previously believed cardio-protective anesthesia (Triethylamine, FlyNap®) is in fact a cardiac depressant, where incremental increases in FlyNap® dose decreases fruit fly heart rate linearly, and also affects the fly heart\u27s response to pacing stress. In summary, a system was developed to measure cardiac function in fruit flies, which allows the future study of cardiac function in genetically manipulated fruit flies under normal and diseased conditions
Eine Typologie des Informationsverhaltens der Deutschen in der Corona-Pandemie unter Berücksichtigung von Themenverdrossenheit
Gesundheitskrisen wie die Corona-Pandemie verlangen einen steten Informationsfluss ausgehend von offiziellen Behörden über die Medien zu den Bürger*innen, um einerseits Panik zu vermeiden und andererseits relevante Informationen zu den aktuellsten Schutzmaßnahmen an die Bevölkerung zu distribuieren. Ausschlaggebend für den Erfolg dieser Kommunikationsmaßnahmen ist jedoch die individuelle Bereitschaft, die bereitgestellten Informationen auch zu rezipieren. Einem Repertoire-Ansatz folgend erforscht die Studie bestehende Muster im Informationsverhalten der Deutschen zu Beginn der Pandemie sowie deren Veränderungen zwischen März und April 2020. Sie untersucht weiterhin, welche Bedeutung soziodemografische Merkmale sowie individuelle, mit der intensiven Berichterstattung in Verbindung stehende Faktoren (Themenverdrossenheit, wahrgenommene Informiertheit) für die Informationssuche haben. Eine zweiwellige Online-Befragung im Panel-Design (N = 1065) diente der Beantwortung dieser Fragen. Im Zuge der Analysen konnten drei zentrale Nutzungstypen mit unterschiedlichen Informationsrepertoires identifiziert werden: Wenignutzende, Traditionalist*innen und Vielnutzende, wobei die Themenverdrossenheit den zentralen Faktor für die Erklärung von Informationsvermeidung darstellt. Dies wirft die Frage auf, wie intensiv die Berichterstattung über ein Thema sein sollte, um ein ausgewogenes Verhältnis zwischen Informationsbedürfnis und Informationssättigung zu erreichen.Health crises like the corona pandemic require a continuous flow of information by official authorities through mass media to the citizens to prevent panic and distribute relevant information on recent preventive measures to the population. Crucial for the success of these communicational measures, however, is the individual willingness of people to receive the provided information. Referring to the media repertoire approach, this study examines existing clusters of informational behavior at the beginning of the pandemic as well as changes thereof between March and April 2020. Furthermore, this study examines the relevance of sociodemographic characteristics and individual factors that cohere with intensive media coverage (topic fatigue, information sufficiency) for information seeking behavior. An online panel with two survey waves (N = 1065) was conducted to examine these questions. As part of the analyses, three types of users with various information repertoires were identified: Rare Users, Traditional Users, and Frequent Users - whereby topic fatigue is the main predictor of information avoidance. This raises the question of how intense the coverage on an issue should be to achieve a balance between the need for information and information saturation
Environment shapes sleep patterns in a wild nocturnal primate
Among primates, the suborder Haplorhini is considered to have evolved a consolidated monophasic sleep pattern, with diurnal species requiring a shorter sleep duration than nocturnal species. Only a few primate species have been systematically studied in their natural habitat where environmental variables, including temperature and light, have a major influence on sleep and activity patterns. Here we report the first sleep study on a nocturnal primate performed in the wild. We fitted seven wild Javan slow lorises (Nycticebus javanicus) in West Java, Indonesia with accelerometers that collected activity data, and installed climate loggers in each individual's home range to collect ambient temperature readings (over 321 days in total). All individuals showed a strictly nocturnal pattern of activity and displayed a striking synchronisation of onset and cessation of activity in relation to sunset and sunrise. The longest consolidated rest episodes were typically clustered near the beginning and towards the end of the light period, and this pattern was inversely related to daily fluctuations of the ambient temperature. The striking relationship between daily activity patterns, light levels and temperature suggests a major role of the environment in shaping the daily architecture of waking and sleep. We concluded that well-known phenotypic variability in daily sleep amount and architecture across species may represent an adaptation to changes in the environment. Our data suggest that the consolidated monophasic sleep patterns shaped by environmental pressures observed in slow lorises represent phylogenetic inertia in the evolution of sleep patterns in humans
The GCN2 kinase is required for activating autophagy in response to indispensable amino acid deficiencies
ORGANIZING COMMITTEEChairs: Didier Attaix - Lydie Combaret - Daniel TaillandierDaniel Béchet - Agnès Claustre - Cécile Coudy-Gandilhon - Christiane Deval - Gérard Donadille - Cécile PolgeSCIENTIFIC COMMITTEEDidier Attaix - Lydie Combaret - Alfred L. Goldberg - Ron Hay - Germana Meroni - Marco Sandri - Daniel Taillandier - Keiji Tanaka - Simon S. WingPoster Session 3 - AutophagyImbalances in dietary amino acid (AA) supply, including deficits in one or more indispensable amino acids (IAA), are stressful conditions for the organism that needs to modulate a number of physiological functions to adapt to this situation. In particular, since there is no system dedicated for storing AA in the body, the release of free AA occurs by proteolysis at the expense of functional proteins, notably in the liver by up-regulating autophagy. This process can be rapidly mobilized within the cell in response to a number of stresses, by post-translational regulations of autophagy-related proteins already present in the cytosol. The protein kinase GCN2 is activated upon IAA scarcity in order to promote cell adaptation to a nutritional stress condition. In response to IAA limitation, GCN2 couples the accumulation of uncharged transfer RNAs to the phosphorylation of eIF2a on serine 51. By this mean, GCN2 diminishes the overall protein synthesis rate, while simultaneously activating a gene expression program mediated by the translational upregulation of the transcription factor ATF4. Our recent work has shown that the GCN2/p-eIF2a/ATF4 signaling pathway plays an essential role in the induction of transcription of a number of autophagy-related genes involved in the maintenance of the autophagic process in response to an IAA deficiency (B’chir et al., 2013). In the present study we sought to determine whether GCN2 could play a role in regulating the early stages of autophagy. The most upstream complex for triggering the autophagic process (initiation complex) is notably composed of the ULK kinase and the ATG13 bridging protein, and is classically viewed to be controlled by mTORC1. Indeed, the activity of the autophagy initiation complex has been shown to be modulated according to AA availability by the activity of mTORC1, which phosphorylates different sites in ULK. Here, by using a GCN2 knock-out mouse model we investigated the role of GCN2 in the upregulation of autophagy in the first hour of an IAA deficiency. Our results show that 1) GCN2 is required for upregulating liver autophagy in response to an IAA-deficient diet, which is confirmed in cell culture model; 2) this early activation of the autophagic process does not require the transcription factor ATF4; 3) moreover, while this effect can occur without concomitant inhibition of mTORC1 activity, our results suggest that ULK/ATG13 couple is involved in the GCN2-dependent activation of autophagy. Our results demonstrate that in the particular model of an IAA deficiency GCN2 plays a preponderant role in triggering the adaptive autophagy upregulation, a mechanism which can operate without concomitant inhibition of mTORC1 activit
Human tumors instigate granulin-expressing hematopoietic cells that promote malignancy by activating stromal fibroblasts in mice
Systemic instigation is a process by which endocrine signals sent from certain tumors (instigators) stimulate BM cells (BMCs), which are mobilized into the circulation and subsequently foster the growth of otherwise indolent carcinoma cells (responders) residing at distant anatomical sites. The identity of the BMCs and their specific contribution or contributions to responder tumor growth have been elusive. Here, we have demonstrated that Scal(+)cKit(-) hematopoietic BMCs of mouse hosts bearing instigating tumors promote the growth of responding tumors that form with a myofibroblast-rich, desmoplastic stroma. Such stroma is almost always observed in malignant human adenocarcinomas and is an indicator of poor prognosis. We then identified granulin (GRN) as the most upregulated gene in instigating Scal(+)cKit(-) BMCs relative to counterpart control cells. The GRN(+) BMCs that were recruited to the responding tumors induced resident tissue fibroblasts to express genes that promoted malignant tumor progression; indeed, treatment with recombinant GRN alone was sufficient to promote desmoplastic responding tumor growth. Further, analysis of tumor tissues from a cohort of breast cancer patients revealed that high GRN expression correlated with the most aggressive triple-negative, basal-like tumor subtype and reduced patient survival. Our data suggest that GRN and the unique hematopoietic BMCs that produce it might serve as novel therapeutic targets
A concise revised Myeloma Comorbidity Index as a valid prognostic instrument in a large cohort of 801 multiple myeloma patients
With growing numbers of elderly multiple myeloma patients, reliable tools to assess their vulnerability are required. The objective of the analysis herein was to develop and validate an easy to use myeloma risk score (revised Myeloma Comorbidity Index) that allows for risk prediction of overall survival and progression-free survival differences in a large patient cohort. We conducted a comprehensive comorbidity, frailty and disability evaluation in 801 consecutive myeloma patients, including comorbidity risks obtained at diagnosis. The cohort was examined within a training and validation set. Multivariate analysis determined renal, lung and Karnofsky Performance Status impairment, frailty and age as significant risks for overall survival. These were combined in a weighted revised Myeloma Comorbidity Index, allowing for the identification of fit (revised Myeloma Comorbidity Index ≤3 [n=247, 30.8%]), intermediate-fit (revised Myeloma Comorbidity Index 4-6 [n=446, 55.7%]) and frail patients (revised Myeloma Comorbidity Index >6 [n=108, 13.5%]): these subgroups, confirmed
validation analysis, showed median overall survival rates of 10.1, 4.4 and 1.2 years, respectively. The revised Myeloma Comorbidity Index was compared to other commonly used comorbidity indices (Charlson Comorbidity Index, Hematopoietic Cell Transplantation-Specific Comorbidity Index, Kaplan-Feinstein Index): if each were divided in risk groups based on 25% and 75% quartiles, highest hazard ratios, best prediction and Brier scores were achieved with the revised Myeloma Comorbidity Index. The advantages of the revised Myeloma Comorbidity Index include its accurate assessment of patients' physical conditions and simple clinical applicability. We propose the revised Myeloma Comorbidity Index to be tested with the "reference" International Myeloma Working Group frailty score in multicenter analyses and future clinical trials. The study was registered at the German Clinical Trials Register (DRKS-00003868)
Environment shapes sleep patterns in a wild nocturnal primate
Among primates, the suborder Haplorhini is considered to have evolved a consolidated monophasic sleep pattern, with diurnal species requiring a shorter sleep duration than nocturnal species. Only a few primate species have been systematically studied in their natural habitat where environmental variables, including temperature and light, have a major influence on sleep and activity patterns. Here we report the first sleep study on a nocturnal primate performed in the wild. We fitted seven wild Javan slow lorises (Nycticebus javanicus) in West Java, Indonesia with accelerometers that collected activity data, and installed climate loggers in each individual’s home range to collect ambient temperature readings (over 321 days in total). All individuals showed a strictly nocturnal pattern of activity and displayed a striking synchronisation of onset and cessation of activity in relation to sunset and sunrise. The longest consolidated rest episodes were typically clustered near the beginning and towards the end of the light period, and this pattern was inversely related to daily fluctuations of the ambient temperature. The striking relationship between daily activity patterns, light levels and temperature suggests a major role of the environment in shaping the daily architecture of waking and sleep. We concluded that well-known phenotypic variability in daily sleep amount and architecture across species may represent an adaptation to changes in the environment. Our data suggest that the consolidated monophasic sleep patterns shaped by environmental pressures observed in slow lorises represent phylogenetic inertia in the evolution of sleep patterns in humans
A concise revised myeloma comorbidity index as a valid prognostic instrument in a large cohort of 801 multiple myeloma patients
With growing numbers of elderly multiple myeloma patients, reliable tools to assess their vulnerability are required. The objective of the analysis herein was to develop and validate an easy to use myeloma risk score (revised Myeloma Comorbidity Index) that allows for risk prediction of overall survival and progression-free survival differences in a large patient cohort. We conducted a comprehensive comorbidity, frailty and disability evaluation in 801 consecutive myeloma patients, including comorbidity risks obtained at diagnosis. The cohort was examined within a training and validation set. Multivariate analysis determined renal, lung and Karnofsky Performance Status impairment, frailty and age as significant risks for overall survival. These were combined in a weighted revised Myeloma Comorbidity Index, allowing for the identification of fit (revised Myeloma Comorbidity Index ≤3 [n=247, 30.8%]), intermediate-fit (revised Myeloma Comorbidity Index 4-6 [n=446, 55.7%]) and frail patients (revised Myeloma Comorbidity Index >6 [n=108, 13.5%]): these subgroups, confirmed via validation analysis, showed median overall survival rates of 10.1, 4.4 and 1.2 years, respectively. The revised Myeloma Comorbidity Index was compared to other commonly used comorbidity indices (Charlson Comorbidity Index, Hematopoietic Cell Transplantation-Specific Comorbidity Index, Kaplan-Feinstein Index): if each were divided in risk groups based on 25% and 75% quartiles, highest hazard ratios, best prediction and Brier scores were achieved with the revised Myeloma Comorbidity Index. The advantages of the revised Myeloma Comorbidity Index include its accurate assessment of patients' physical conditions and simple clinical applicability. We propose the revised Myeloma Comorbidity Index to be tested with the “reference” International Myeloma Working Group frailty score in multicenter analyses and future clinical trials
Drug-induced eRF1 degradation promotes readthrough and reveals a new branch of ribosome quality control.
Suppression of premature termination codons (PTCs) by translational readthrough is a promising strategy to treat a wide variety of severe genetic diseases caused by nonsense mutations. Here, we present two potent readthrough promoters-NVS1.1 and NVS2.1-that restore substantial levels of functional full-length CFTR and IDUA proteins in disease models for cystic fibrosis and Hurler syndrome, respectively. In contrast to other readthrough promoters that affect stop codon decoding, the NVS compounds stimulate PTC suppression by triggering rapid proteasomal degradation of the translation termination factor eRF1. Our results show that this occurs by trapping eRF1 in the terminating ribosome, causing ribosome stalls and subsequent ribosome collisions, and activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25
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