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Elevated expression of acetylcholinesterase (AChE) is a common characteristic of apoptotic cells in both invertebrate and vertebrate species. While increased levels of acetylcholinesterase sensitize cells to apoptogenic stimuli, its absence or pharmacological inactivation interferes with apoptotic cell death. acetylcholinesterase may exert its pro-apoptotic function directly as an integral component of the apoptotic molecular machinery or indirectly by limiting the availability of receptor ligands and structural binding partners that promote cell survival under non-apoptogenic conditions. acetylcholinesterase promotes formation of the apoptosome and degrades DNA after nuclear accumulation. Its esterase activity limits the availability of acetylcholine as ligand for cell membrane-located nicotinic and muscarinic ACh-receptors and mitochondrial nicotinic ACh-receptors that normally support vital physiological states. Studies on insects suggest, that cytokine-activated cell-protective pathways may suppress acetylcholinesterase overexpression under apoptogenic conditions to prevent apoptotic cell death. We provide an overview of studies on various organisms and cell types that summarizes the contribution of acetylcholinesterase to the progress of apoptosis via multiple mechanisms.

Cytokine receptor like factor 3 (CRLF3) is a conserved cytokine receptor present in all major eumetazoan taxa. Though vertebrate CRLF3 has recently been implied in the regulation of hematopoiesis, its ligand remained unidentified. CRLF3 shares structural similarity with receptors for other hematopoietic growth factors including erythropoietin, thrombopoietin and granulocyte colony-stimulating factor. Besides hematopoietic organs, these established hematopoietic cytokines and their receptors are also widely expressed in other tissues including the nervous system, where they regulate proliferation, differentiation, cell survival and other homeostatic processes. Previous studies identified insect CRLF3 as a neuroprotective receptor that can be activated by human recombinant erythropoietin, a widely accepted protective cytokine in vertebrate nervous systems. Epo’s erythropoietic functions mediated by classical Epo receptor are understood in great detail whereas Epo-mediated cytoprotective mechanisms are more complex due to involvement of additional Epo receptors and a splice variant (EV-3) with selectivity for certain unidentified receptors. In the present study, we show that human CRLF3 mediates neuroprotection upon activation with the natural Epo splice variant EV-3. We generated CRLF3 knock out iPSC lines and differentiated them towards the neuronal lineage. While apoptotic death of rotenone-challenged wild type iPSC-derived neurons was prevented by EV-3, EV-3-mediated neuroprotection was absent in CRLF3 knock out neurons. Rotenone-induced apoptosis and EV-3-mediated neuroprotection were associated with differential expression of pro- and anti-apoptotic genes. Our data characterize human CRLF3 as a receptor involved in Epo-mediated neuroprotection and identify CRLF3 as the first known receptor for EV-3.

1AbstractBehaviour involving two or more individuals within the same species is known as social behaviour. Sexual dimorphisms and environmental cues as well as age, experience and social hierarchy shape social behaviour. The study of this complex behaviour, however, has one essential boundary condition: the distance between individuals. Because social signals (e.g. acoustic, visual or olfactory) have limited reach the inter-individual distance is crucial for the correct transmission of such signals. In this study we present a newly developed assay to study group behaviour and inter-individual distance in Drosophila melanogaster. This assay consists of a circular observation space flanked by two automatic release devices that allow flies to enter individually. By releasing the flies one at a time, the observer can study different features of (intra-)group behaviour with different group compositions. Importantly, the observer can control (manually or through automatisation) the increase of group size over time.Over the last decades insects became more relevant as convenient model organisms to study the neurophysiological and genetic basis of (human) neuro-developmental disorders. Drosophila models are used to study the genetic and neuronal underpinnings of a wide range of neurological disorders. In some cases the studies revealed alterations in social behaviour consistent with descriptions of behavioural symptoms in human disorders.Social behaviours in Drosophila are well-studied and include courtship, mating, aggression and group interactions. This setup will facilitate the analysis of these aspects of group interactions in Drosophila, allowing for a deeper understanding of the neuronal circuits and genetic factors involved in those behaviours.2Contribution to the fieldSocial behaviour pertains to the most sophisticated behavioural feats, as it involves multiple, interacting individuals. These complex interactions often conceal the underlying neuronal and ethological mechanisms. One of the most basal ethological mechanisms is the inter-individual distance, which resembles a perimeter in which each individual needs to formulate a response to the approach of others.We introduce a device that allows to test the inter-individual distance under consistent circumstances, by automating the entry time and direction of conspecifics into the arena. We can further observe the composition, dynamics and forming of larger animal groups as well as their separating. We can also observe how the individual distances alter during the process. Also other behaviours can be easily observed, e.g. aggression, courtship, homosexual courtship, etc. We successfully employed this approach in [1] and could discriminate the role of different neuroligins in social behaviour. We provide a detailed description including building plans and material lists for this social observation device. The system can be run in an automatic mode to ensure the consistency of experiments or in a manual mode to test animals under more flexible social situations. We provide multiple back lighting systems to test animals in the dark (infra-red LEDs) or in illuminated environments (vis. range LEDs). The system is fully automated and can be linked with a number of animal trackers (e.g. T-Rex, deeplabcut, LACE, etc.) via simple videography. We hope that our experimental setup augments the variety of behaviours testable in ethological setups (T-maze, water-mazes, operant conditing setups, etc) with social interaction and group formation.

High-fidelity flight maneuver simulations are crucial for the development of realistic digital aircraft models. However, such simulations are still hampered by difficulties in modeling the relative body motion between control and lifting surfaces when using realistic configurations. The presence of spanwise gaps between lifting and control surfaces impedes the application of concepts such as mesh deformation, and hampers the usage of mesh deformation combined with the overset method since the mesh generation process is particularly cumbersome. To reduce the user effort to create overset meshes, we have developed a methodology to automatically create overlapping regions for matching block interfaces. Hence, the usage of the overset method combined with mesh deformation for modeling moving control surfaces is facilitated, and a significant advance towards the computation of high-fidelity flight maneuvers is achieved.

Tumor–endothelial cell interactions represent an essential mechanism in spinal metastasis. Ephrin-B2–EphB4 communication induces tumor cell repulsion from the endothelium in metastatic melanoma, reducing spinal bone metastasis formation. To shed further light on the Ephrin-B2–EphB4 signaling mechanism, we researched the effects of pharmacological EphB4 receptor stimulation and inhibition in a ligand-dependent/independent context. We chose a preventative and a post-diagnostic therapeutic window. EphB4 stimulation during tumor cell seeding led to an increase in spinal metastatic loci and number of disseminated melanoma cells, as well as earlier locomotion deficits in the presence of endothelial Ephrin-B2. In the absence of endothelial Ephrin-B2, reduction of metastatic loci with a later manifestation of locomotion deficits occurred. Thus, EphB4 receptor stimulation affects metastatic dissemination depending on the presence/absence of endothelial Ephrin-B2. After the manifestation of solid metastasis, EphB4 kinase inhibition resulted in significantly earlier manifestation of locomotion deficits in the presence of the ligand. No post-diagnostic treatment effect was found in the absence of endothelial Ephrin-B2. For solid metastasis treatment, EphB4 kinase inhibition induced prometastatic effects in the presence of endothelial Ephrin-B2. In the absence of endothelial Ephrin-B2, both therapies showed no effect on the growth of solid metastasis.

A tremendous number of gust-load cases need to be computed during the aircraft design and certification process. From an aerodynamic point of view, gust-load predictions in industry rely on linear ...

The development, testing and production of new aircraft are associated with considerable temporal and financial risks due to the product and manufacturing complexity. In order to accelerate the introduction of innovative technologies for more economical, more environmentally friendly and safer air vehicles and to better control the technological risks involved, DLR’s guiding concept The Virtual Product aims at virtualizing the design, development and manufacturing processes, including the definition of an appropriate validation strategy. The availability of high fidelity simulation tools with the capability to model multidisciplinary phenomena is a decisive part in that context. High demands are put on the numerical methods and solvers as the tools must provide reliable results in a robust manner for the entire flight envelope where nonlinearities are prominent in most of the disciplines. A key technology is the ability to enable Virtual Flight Testing based on high-fidelity simulation tools. The progress made at the German Aerospace Center (DLR) in the recent past regarding the development of methods and tools to perform virtual flight tests is presented in two papers. The first paper (Virtual Aircraft Technology Integration Platform: Ingredients for Multidisciplinary Simulation System and Virtual Flight Testing) gives an overview of the development of components required for virtual flight testing. The present paper outlines the methods, the framework, and the simulation models for particular applications, the virtual system identification flights of a medium size jet transport. Aerodynamics, structural dynamics, flight mechanics and propulsion are considered for the massively-parallel, time-domain simulations.

The development, testing and production of new aircraft are associated with considerable temporal and financial risks due to the product and manufacturing complexity. In order to accelerate the introduction of innovative technologies for more economical, more environmentally friendly and safer air vehicles and to better control the technological risks involved, DLR's guiding concept 'The Virtual Product' aims at virtualizing the design, development and manufacturing processes, including the definition of an appropriate validation strategy. The availability of high-fidelity simulation tools with the capability to model multidisciplinary phenomena is a decisive part in that context. High demands are put on the numerical methods and solvers as the tools must provide reliable results in a robust manner for the entire flight envelope where nonlinearities are prominent in most of the disciplines. A key technology is the ability to enable 'virtual flight testing' based on high-fidelity simulation tools. The progress made at the German Aerospace Center (DLR) in the recent past regarding the development of methods and tools for performing virtual flight tests is presented. The content is split in two papers. The second paper ('Virtual Aircraft Technology Integration Platform: From Virtual Flight Testing towards Simulation-based Certification') presents (for the sake of system identification purposes) virtual flight tests of a medium size short-haul transport aircraft using many of the simulation ingredients described in the present paper. Aerodynamics, structural dynamics, flight mechanics and propulsion are considered in the massively-parallel, time-domain simulation of longitudinal and multi-axis maneuvers. Validations against experimental data of real flight tests for the same aircraft are presented; the accuracy of the virtual flight test approach and the multidisciplinary framework are discussed. The present paper gives an overview of the development status of the building blocks required for virtual flight testing, and it described the simulation framework FlowSimulator used for the integration. Verification and validation aspects concerning the monodisciplinary components and the overall framework are addressed. Further ingredients required for virtual flight testing, including the modeling of atmospheric effects and dynamic deflection of control surfaces, mesh deformation, spatial CFD/CSM coupling, trimming and the development of the next generation CFD solver CODA are described. Selected applications are discussed, demonstrating the capabilities that are available.

Acoustic communication in insects serves mate attraction, courtship, aggregation, competition, territoriality, and predation and may inform a conspecific receiver about the physiological status of the sender. Acoustic signals are associated with particular behaviors and should only be performed in the correct context. This context is internally represented by neuroendocrinal signals. Hormones released from endocrine organs and neurosecretory regions establish or reconfigure neural circuits and determine general physiological states, which represent permissive requirements for the execution of a particular behavior that may include sound production. Neuromodulators alter the sensitivity of sensory and decision making premotor circuits to regulate the likelihood, specific pattern and intensity of sound production or other behaviors on a minute timescale. Neurotransmitters serve as immediate triggers for the initiation of sound production in response to actual sensory input and mediate the fine-tuned synaptic transmission in pattern-generating circuits. Different aspects of the neuroendocrinal regulation of acoustic sensory-to-motor processing have been studied in relatively few insect species, most intensively in grasshoppers, crickets, bushcrickets, honey bees, and fruit flies.

Apoptosis plays a major role in development, tissue renewal and the progression of degenerative diseases. Studies on various types of mammalian cells reported a pro-apoptotic function of acetylcholinesterase (AChE), particularly in the formation of the apoptosome and the degradation of nuclear DNA. While three AChE splice variants are present in mammals, invertebrates typically express two ache genes that code for a synaptically located protein and a protein with non-synaptic functions respectively. In order to investigate a potential contribution of AChE to apoptosis in insects, we selected the migratory locust Locusta migratoria. We established primary neuronal cultures of locust brains and characterized apoptosis progression in vitro. Dying neurons displayed typical characteristics of apoptosis, including caspase-activation, nuclear condensation and DNA fragmentation visualized by TUNEL staining. Addition of the AChE inhibitors neostigmine and territrem B reduced apoptotic cell death under normal culture conditions. Moreover, both inhibitors completely suppressed hypoxia-induced neuronal cell death. Exposure of live animals to severe hypoxia moderately increased the expression of ace-1 in locust brains in vivo. Our results indicate a previously unreported role of AChE in insect apoptosis that parallels the pro-apoptotic role in mammalian cells. This similarity adds to the list of apoptotic mechanisms shared by mammals and insects, supporting the hypothesized existence of an ancient, complex apoptosis regulatory network present in common ancestors of vertebrates and insects. Electronic supplementary material The online version of this article (10.1007/s10495-020-01630-4) contains supplementary material, which is available to authorized users.

We investigated brain regions – mostly neuropils – that process auditory information relevant for the initiation of response songs of female grasshoppers Chorthippus biguttulus during bidirectional intraspecific acoustic communication. Male-female acoustic duets in the species Ch. biguttulus require the perception of sounds, their recognition as a species- and gender-specific signal and the initiation of commands that activate thoracic pattern generating circuits to drive the sound-producing stridulatory movements of the hind legs. To study sensory-to-motor processing during acoustic communication we used multielectrodes that allowed simultaneous recordings of acoustically stimulated electrical activity from several ascending auditory interneurons or local brain neurons and subsequent electrical stimulation of the recording site. Auditory activity was detected in the lateral protocerebrum (where most of the described ascending auditory interneurons terminate), in the superior medial protocerebrum and in the central complex, that has previously been implicated in the control of sound production. Neural responses to behaviorally attractive sound stimuli showed no or only poor correlation with behavioral responses. Current injections into the lateral protocerebrum, the central complex and the deuto-/tritocerebrum (close to the cerebro-cervical fascicles), but not into the superior medial protocerebrum, elicited species-typical stridulation with high success rate. Latencies and numbers of phrases produced by electrical stimulation were different between these brain regions. Our results indicate three brain regions (likely neuropils) where auditory activity can be detected with two of these regions being potentially involved in song initiation.

Recent studies have demonstrated that Drosophila melanogaster (briefly Drosophila) can successfully perform higher cognitive processes including second order olfactory conditioning. Understanding the neural mechanism of this behavior can help neuroscientists to unravel the principles of information processing in complex neural systems (e.g. the human brain) and to create efficient and robust robotic systems. In this work, we have developed a biologically-inspired spiking neural network which is able to execute both first and second order conditioning. Experimental studies demonstrated that volume signaling (e.g. by the gaseous transmitter nitric oxide) contributes to memory formation in vertebrates and invertebrates including insects. Based on the existing knowledge of odor encoding in Drosophila, the role of retrograde signaling in memory function, and the integration of synaptic and non-synaptic neural signaling, a neural system is implemented as Simulated fly. Simulated fly navigates in a two-dimensional environment in which it receives odors and electric shocks as sensory stimuli. The model suggests some experimental research on retrograde signaling to investigate neural mechanisms of conditioning in insects and other animals. Moreover, it illustrates a simple strategy to implement higher cognitive capabilities in machines including robots.

Aggression is a universal social behavior important for the acquisition of food, mates, territory, and social status. Aggression in Drosophila is context-dependent and can thus be expected to involve inputs from multiple sensory modalities. Here, we use mechanical disruption and genetic approaches in Drosophila melanogaster to identify hearing as an important sensory modality in the context of intermale aggressive behavior. We demonstrate that neuronal silencing and targeted knockdown of hearing genes in the fly’s auditory organ elicit abnormal aggression. Further, we show that exposure to courtship or aggression song has opposite effects on aggression. Our data define the importance of hearing in the control of Drosophila intermale aggression and open perspectives to decipher how hearing and other sensory modalities are integrated at the neural circuit level.

Transcutaneous measurement of the glomerular filtration rate ( t GFR) is now frequently used in animal studies. t GFR allows consecutive measurements on the same animal, including multiple measurements on a daily basis, because no blood sampling is required. Here we derive and validate a novel kinetic model for the description of transcutaneously measured FITC-Sinistrin excretion kinetics. In contrast to standard 1- to 3-compartment models, our model covers the complete kinetic, including injection and distribution of the tracer in the plasma compartment. Because the model describes the complete progression of the measurement, it allows further refinement by correcting for baseline shifts observed occasionally during measurement. Possible reasons for shifts in the background signal include photo bleaching of the skin, autofluorescence, changes of physiological state of the animals during the measurements, or effects arising from the attachment of the measurement device. Using the new 3-compartment kinetic model with modulated baseline ( t GFR 3cp.b.m ), t GFR measurements in rats can reach comparable precision as those from GFR measurements assessed using a gold standard technique based on constant infusion of a tracer. Moreover, the variability of simultaneous (parallel) measurements, as well as repeated t GFR measurements in the same animals, showed higher precision when t GFR 3cp.b.m was compared with the 1-compartment t GFR 1cp model.

It is common practice in aircraft industry to perform maneuver and gust loads computations on the basis of potential theory aerodynamics methods that neglect important physical effects. In order to master the future challenges of aviation, however, there is a need for higher-precision loads computations. For this and other purposes, the RANS-CFD-based multidisciplinary simulation environment FlowSimulator is being developed. The status of selected features of the environment related to higher-precision maneuver simulations is presented; example applications are discussed.

In addition to its regulatory function in the formation of red blood cells (erythropoiesis) in vertebrates, Erythropoietin (Epo) contributes to beneficial functions in a variety of non-hematopoietic tissues including the nervous system. Epo protects cells from apoptosis, reduces inflammatory responses and supports re-establishment of compromised functions by stimulating proliferation, migration and differentiation to compensate for lost or injured cells. Similar neuroprotective and regenerative functions of Epo have been described in the nervous systems of both vertebrates and invertebrates, indicating that tissue-protective Epo-like signaling has evolved prior to its erythropoietic function in the vertebrate lineage. Epo mediates its erythropoietic function through a homodimeric Epo receptor (EpoR) that is also widely expressed in the nervous system. However, identification of neuroprotective but non-erythropoietic Epo splice variants and Epo derivatives indicated the existence of other types of Epo receptors. In this review, we summarize evidence for potential Epo receptors that might mediate Epo’s tissue-protective function in non-hematopoietic tissue, with focus on the nervous system. In particular, besides EpoR, we discuss three other potential neuroprotective Epo receptors: (1) a heteroreceptor consisting of EpoR and common beta receptor (βcR), (2) the Ephrin (Eph) B4 receptor and (3) the human orphan cytokine receptor-like factor 3 (CRLF3).

A tremendous number of gust load cases needs to be computed during the aircraft design and certification process. From an aerodynamic point of view, gust loads predictions in industry rely on linear potential flow methods which are inappropriate at transonic flight conditions. Prediction accuracy can be enhanced by accounting for aerodynamic loads computed with computational fluid dynamics, eventually resulting in lighter, more efficient designs. However, full order, unsteady time-marching simulations are still prohibitively expensive in an industrial environment. Therefore, different reduced order modelling techniques have been propose to decrease computational cost in many query scenarios while retaining the underlying physics and a high level of accuracy. This paper focuses on an unsteady nonlinear reduced order model based on least squares residual minimization and a comparison to the linearized frequency domain method. While the latter is in line with current industrial practice of sampling aerodynamic forces in the frequency domain, it neglects dynamic nonlinearities which are included in the former approach. Results are presented for an airfoil at transonic flow conditions exhibiting shock induced Separation during the airfoil-gust interaction and for the NASA common research model at cruise flight conditions. Essential quantities for the gust loads analysis, such as global coefficients and sectional forces, are evaluated and compared to highlight strengths and weaknesses of both model reduction techniques. Moreover, distributed surface loads, which can be used for a direct sizing of the structural model, are analyzed. Computational cost, split in an offline and an online part, is quantified to demonstrate efficiency gains compared to full-order solutions.

Neuroligins represent a family of phylogenetically conserved adhesion molecules that regulate synaptic physiology. Their malfunction is associated with autism spectrum disorders. Courtship and aggression of Drosophila melanogaster can serve as a model system to study the function of neuroligins in the proper execution of social behaviours, communication and cognitive tasks, the functions that are compromised in autistic patients.

Traumatic brain injury causes progressive brain atrophy and cognitive decline. Surprisingly, an early treatment with erythropoietin (EPO) prevents these consequences of secondary neurodegeneration, but the mechanisms have remained obscure. Here we show by advanced imaging and innovative analytical tools that recombinant human EPO, a clinically established and neuroprotective growth factor, dampens microglial activity, as visualized also in vivo by a strongly attenuated injury-induced cellular motility.

The cytokine erythropoietin (Epo) mediates protective and regenerative functions in mammalian nervous systems via activation of poorly characterized receptors that differ from the "classical" homodimeric Epo receptor expressed on erythroid progenitor cells. Epo genes have been identified in vertebrate species ranging from human to fish, suggesting that Epo signaling evolved earlier than the vertebrate lineage. Studies on insects (Locusta migratoria, Chorthippus biguttulus, Tribolium castaneum) revealed Epo-mediated neuroprotection and neuroregeneration. Recombinant human Epo (rhEpo) prevents apoptosis by binding to a janus kinase-associated receptor, stimulation of STAT transcription factors, and generation of factors that prevent the activation of proapoptotic caspases. Insect neurons were also protected by a neuroprotective but nonerythropoietic Epo splice variant, suggesting similarity with mammalian neuroprotective but not with homodimeric "classical" Epo receptors. Additionally, rhEpo promotes the regeneration of neurites in primary cultured insect brain neurons and after nerve crush in an in vivo preparation. In contrast to neuroprotective and regenerative effects shared with mammalian species, no evidence for a role of Epo signaling in the regulation of neuro- or gliogenesis was found in insects. Similar structural and functional characteristics of the Epo binding receptors, partly shared transduction pathways that prevent apoptosis and the functional implication in neuroprotective and neuroregenerative processes in both mammalian and insect species, suggest that Epo-like signaling was already established in their last common ancestor. Originally functioning as a tissue-protective response to unfavorable physiological situations, cell injury, and pathogen invasion, Epo was later adapted as a humoral regulator of erythropoiesis in the vertebrate lineage.

Aggression is a universal social behavior important for the acquisition of food, mates, territory, and social status. Aggression in

The coupling devices for RF immunity testing in close proximity defined in the new basic standard IEC 61000-4-39 are TEM horn antennas. The required parameters for TEM horn antennas are investigated based on simulations and measurements. In addition the practical relevance of the test method has been investigated with respect to the field properties as well as for an example of a practical mobile transmit antenna.

The cytokine erythropoietin (Epo) mediates protective and regenerative functions in mammalian nervous systems via activation of poorly characterized receptors that differ from the "classical" homodimeric Epo receptor expressed on erythroid progenitor cells. Epo genes have been identified in vertebrate species ranging from human to fish, suggesting that Epo signaling evolved earlier than the vertebrate lineage. Studies on insects (Locusta migratoria, Chorthippus biguttulus, Tribolium castaneum) revealed Epo-mediated neuroprotection and neuroregeneration. Recombinant human Epo (rhEpo) prevents apoptosis by binding to a janus kinase-associated receptor, stimulation of STAT transcription factors, and generation of factors that prevent the activation of proapoptotic caspases. Insect neurons were also protected by a neuroprotective but nonerythropoietic Epo splice variant, suggesting similarity with mammalian neuroprotective but not with homodimeric "classical" Epo receptors. Additionally, rhEpo promotes the regeneration of neurites in primary cultured insect brain neurons and after nerve crush in an in vivo preparation. In contrast to neuroprotective and regenerative effects shared with mammalian species, no evidence for a role of Epo signaling in the regulation of neuro- or gliogenesis was found in insects. Similar structural and functional characteristics of the Epo binding receptors, partly shared transduction pathways that prevent apoptosis and the functional implication in neuroprotective and neuroregenerative processes in both mammalian and insect species, suggest that Epo-like signaling was already established in their last common ancestor. Originally functioning as a tissue-protective response to unfavorable physiological situations, cell injury, and pathogen invasion, Epo was later adapted as a humoral regulator of erythropoiesis in the vertebrate lineage.

The cytokine erythropoietin (Epo) mediates various cell homeostatic responses to environmental challenges and pathological insults. While stimulation of vertebrate erythrocyte production is mediated by homodimeric “classical” Epo receptors, alternative receptors are involved in neuroprotection. However, their identity remains enigmatic due to complex cytokine ligand and receptor interactions and conflicting experimental results. Besides the classical Epo receptor, the family of type I cytokine receptors also includes the poorly characterized orphan cytokine receptor-like factor 3 (CRLF3) present in vertebrates including human and various insect species. By making use of the more simple genetic makeup of insect model systems, we studied whether CRLF3 is a neuroprotective Epo receptor in animals. We identified a single ortholog of CRLF3 in the beetle Tribolium castaneum, and established protocols for primary neuronal cell cultures from Tribolium brains and efficient in vitro RNA interference. Recombinant human Epo as well as the non-erythropoietic Epo splice variant EV-3 increased the survival of serum-deprived brain neurons, confirming the previously described neuroprotective effect of Epo in insects. Moreover, Epo completely prevented hypoxia-induced apoptotic cell death of primary neuronal cultures. Knockdown of CRLF3 expression by RNA interference with two different double stranded RNA (dsRNA) fragments abolished the neuroprotective effect of Epo, indicating that CRLF3 is a crucial component of the insect Epo-responsive receptor. This suggests that a common urbilaterian ancestor of the orphan human and insect cytokine receptor CRLF3 served as a neuroprotective receptor for an Epo-like cytokine. Our work also suggests that vertebrate CRLF3, like its insect ortholog, might represent a tissue protection-mediating receptor.

Autism spectrum disorders (ASDs) are characterized by deficits in social interactions, language development and repetitive behaviours. Multiple genes involved in the formation, specification and maintenance of synapses have been identified as risk factors for ASDs development. Among these are the neuroligin genes which code for postsynaptic cell adhesion molecules that induce the formation of presynapses, promote their maturation and modulate synaptic functions in both vertebrates and invertebrates. Neuroligin-deficient mice display abnormal social and vocal behaviours that resemble ASDs symptoms. Here we show for the fly Drosophila melanogaster that deletion of the dnl2 gene, coding for one of four Neuroligin isoforms, impairs social interactions, alters acoustic communication signals, and affects the transition between different behaviours. dnl2 -Deficient flies maintain larger distances to conspecifics and males perform less female-directed courtship and male-directed aggressive behaviours while the patterns of these behaviours and general locomotor activity were not different from wild type controls. Since tests for olfactory, visual and auditory perception revealed no sensory impairments of dnl2 -deficient mutants, reduced social interactions seem to result from altered excitability in central nervous neuropils that initiate social behaviours. Our results demonstrate that Neuroligins are phylogenetically conserved not only regarding their structure and direct function at the synapse but also concerning a shared implication in the regulation of social behaviours that dates back to common ancestors of humans and flies. In addition to previously described mouse models, Drosophila can thus be used to study the contribution of Neuroligins to synaptic function, social interactions and their implication in ASDs.

Erythropoietin (Epo) plays a dual role as an erythropoiesis-stimulating hormone and a locally produced cytoprotectant in various vertebrate tissues. Splice variants and engineered derivatives of Epo that mediate neuroprotection but do not stimulate erythropoiesis suggest that alternative receptors, different from the 'classical' homodimeric receptor involved in haematopoiesis, mediate neuroprotective Epo functions. Previous studies on grasshoppers demonstrated neuroprotective and neuroregenerative effects of Epo that involved similar transduction pathways as in mammals. To advance the characterization of yet unidentified neuroprotective Epo receptors, we studied the neuroprotective potency of the human non-erythropoietic Epo splice variant EV-3 in primary cultured locust brain neurons. We demonstrate that EV-3, like Epo, protects locust neurons from hypoxia-induced apoptotic death through activation of the Janus kinase/signal transducer and activator of transcription transduction pathway. Using the fluorescent dye FM1-43 to quantify endocytotic activity we show that both Epo and EV-3 increase the number of fluorescently labelled endocytotic vesicles. This reveals that binding of Epo to its neuroprotective receptor induces endocytosis, as it has been described for the mammalian homodimeric Epo-receptor expressed by erythroid progenitors. Reduction in Epo-stimulated endocytotic activity following pre-exposure to EV-3 indicated that both Epo and its splice variant bind to the same receptor on locust neurons. The shared neuroprotective potency of Epo and EV-3 in insect and mammalian neurons, in the absence of erythropoietic effects of EV-3 in mammals, suggests a greater similarity of the unidentified nervous Epo receptors (or receptor complexes) across phyla than between mammalian haematopoietic and neuroprotective receptors. Insects may serve as suitable models to evaluate the specific protective mechanisms mediated by Epo and its variants in non-erythropoietic mammalian tissues.

Numerical stall simulations are challenging in terms of physical models involved, overall computation effort, and the needed efforts for validation. The present paper describes coordinated, fundamental research into new simulation methodologies and their validation for wing and nacelle stall that also include the effects of atmospheric gusts. The research is carried out by the DFG funded Research Unit FOR 1066, which is composed of German Universities and the German Aerospace Center, DLR. The Research Unit investigates advanced models of turbulence, advanced physics-based gust models, and new numerical approaches for gust simulation. These modeling and computational activities are supplemented by new validation experiments, that aim at providing stall data on wings and engine nacelles with well defined, generic distortions of the onset flow.

A concept is presented for the numerical simulation of trimmed aircraft flight in steady-state conditions under the influence of working engines. An important ingredient in this process is the numerical engine boundary treatment. The engine boundary fluxes were computed following the flux-difference scheme of Roe in combination with an engine-specific definition of the fluid state. An elementary prototype configuration was considered first to verify the steady-state trim procedure in 2D. The desired flight equilibrium was found in a few Newton iterations controlling the engine, the pitch angle and the angle of the horizontal tail plane. Subsequently, a 3D configuration of a generic transport aircraft was considered in cruise conditions. As a first step towards the computation of a steady-state flight equilibrium, the CFD simulation has been performed for an initial configuration with working engines.

Currently, more and more laboratories are acquiring the capability of simultaneously detecting the extracellular activity of neurons in anaesthetized and awake animals by multielectrode recordings. In insects, multielectrode recordings are challenging due to the small size of the nervous system. Nevertheless, multielectrode recordings have been successfully established in brains of cockroaches, honeybees, fruit flies and grasshoppers to study sensory processing related to mechanosensation, olfaction, vision and audition. The number of neurons which can be recorded using such multielectrodes did not exceed 5 and likely depends on factors like recorded compartment of the neuron, impedance of the multielectrode, number of wires included in the multielectrode and threshold for spike detection. Signal-to-noise ratio (SNR) of the recordings obviously depends on the material and method used for the production of multielectrodes. To mark the location of the recording, different methods like current-driven copper deposition, labelling with fluorescent dye and electrocoagulation of nervous tissue are used. As expected, multielectrode recordings are more difficult in freely moving compared to restrained insects due to movement artifacts and requirement for fixed placement of the multielectrode at a particular recording site in the central nervous system (CNS). Specific characteristics of different preparations and sensory systems that include, disentangling spike collisions connected to auditory stimulation, increase in SNR after extended recording periods in olfactory systems and photoelectrical effects from compound eyes associated with visual stimulation, may require special attention and particular adaptations. unKnown

Animal species of various phyla possess neuroendocrine glands whose hormonal products regulate developmental and physiological mechanisms and directly impact behavior. Two examples, the corpora allata of insects and the vertebrate adenohypophysis have previously been regarded as analogous tissues that evolved independently from diffuse epidermal nerve nets of early metazoans. More recent developmental and functional studies accumulated evidence suggesting that the bilaterian nervous systems including its modern parts (e.g. pallium or cortex and mushroom bodies) and its neuroendocrine appendages (that are considered to be more ancient structures) possess a single evolutionary origin. The corpora allata of insects and the vertebrate adenohypophysis share a number of characteristics in respect of morphology, control of hormone release by RFamides, metabolites produced by closely related cytochrome P450 enzymes and gene expression during embryonic development. This review incorporates latest findings into an extensive description of similarities between insect corpora allata and vertebrate adenohypophysis that should encourage further studies about the onto- and phylogenetic origin of these neuroendocrine glands.

This paper presents a surrogate-enhanced methodology for high-fidelity simulation of aircraft in trimmed state. Surrogates of the aerodynamic loads are used to increase robustness and reduce the number of costly high-fidelity simulations necessary during trim simulations. This is accomplished in two steps: (1) by finding a suitable estimate for the solution by global and fast local searches performed on surrogates, and (2) by applying a hybrid local search to check the potential solution and to further increase its quality if necessary. For the local searches in both steps, a Newton method is employed, whereas a genetic algorithm is used only in the first step. For the Newton method, the entries of the Jacobian are provided by means of finite difference approximations and the complex-step derivative method (CSD) based on the surrogates, and it is shown how to make CSD applicable to surrogates based on radial basis functions (RBFs). In the hybrid search, the derivatives are calculated by means of surrogates, while high-fidelity simulations are used for the main calculations of the Newton method. Updating the surrogates with the results of the latter is found to significantly accelerate the convergence of the hybrid local search. The methodology is applied to challenging trim test cases, in which several of the control surfaces of a generic fighter aircraft are deflected during trim simulation. Control surface deflection is performed via RBF-based mesh deformation, and RBFs are also used for surrogate modeling, thereby fostering code modularity and re-use.

The effect of ecdysteroid signaling on Drosophila female precopulatory behavior was investigated using two types of mutants with either globally reduced ecdysteroid availability or reduced expression of ecdysone receptors in fruitless neurons, known to control sexual behavior. While being courted by males, mutant females performed significantly less full ovipositor extrusion behavior to reject male copulation attempts. Ecdysteroid depleted females (ecdysoneless(1)) performed male-like courtship behaviors, including unilateral wing extension and song production with patterns very similar to male courtship song. These results support the hypothesis that ecdysteroids modulate female sexual behavior, perhaps acting as a regulator of sexual motivation, and as a component affecting the performance of sex specific behavior patterns.