Gene-environment interplay of extreme anxiety-related behavior

The use of selectively bred mouse models of enhanced fear and/or anxiety-related behavior provides a unique opportunity to identify genetic targets that contribute to pathological anxiety. However, dealing with animal models needs accurate information about their phenotypes. Accordingly, high (HAB), normal (NAB) and low (LAB) anxiety-related behavior mice ? a validated model of anxiety disorders - were repeatedly tested in a variety of behavioral paradigms. Whereas most tests to assess anxiety traits are based on fear of novel and open spaces, we took advantage of the inborn fear and associated avoidance of the predator odor (trimethylthiazoline (TMT)) as a measure of anxiety-related behavior. We were able to show that avoidance of TMT reflects the high anxiety phenotype of HAB mice, indicated by the decreased time animals spent in the chamber with TMT compared to NAB and LAB mice. Importantly, this result is not confounded by any deficit of the olfactory system, since mice responded to both the pleasant odor of female urine and the repugnant odor of butyric acid. To take the influence of environmental stimuli on inborn anxiety further, we next studied the impact of environmental manipulations on the genetically driven phenotype of LAB mice. Therefore, animals were exposed to a series of chronic unpredictable mild stressors (CMS). CMS-treated mice displayed increased anxiety in the TMT-avoidance test, elevated plus-maze (EPM) and light-dark box (LDB). Moreover, these animals were characterized by increased depression-like behavior and a blunted neuroendocrine regulation. Furthermore, TMT-exposure promoted a higher activation of immediate early gene expression, e.g. c-fos, in the amygdala, especially in the basolateral nuclei (BLA). c-Fos expression pattern correlated with anxiety-related behavior after CMS. Importantly, our electrophysiological studies also indicated a higher activation of amygdala in LAB mice after CMS treatment. Since corticotropin releasing hormone (CRH) is one of the most important mediators of amygdala activity and is largely involved in the regulation of the anxiety-related behavior, we hypothesized that environmental influences are translated via an altered CRH system. Previous experiments had shown that enriched environment (EE) induced a down-regulation of Crhr1. Here, we report that CMS induced higher expression of Crhr1 in the BLA of LAB mice, in contrast to EE. Thus, these data indicate, that Crhr1 expression might be plastic in response to both, beneficial and detrimental, environmental factors. Thereafter, we studied the role of DNA methylation as a probable mechanism behind the different gene expression. Using pyrosequencing of the bisulfite-converted DNA, one specific CpG site (CpG1) of Crhr1 was found to be higher methylated after both treatments. In order to evaluate functional importance of this modification, we tested the impact of CpG1 methylation on promoter activity using the luciferase assay and observed that the presence of methylation reduced promoter activity. Moreover, elevated methylation decreased the binding efficiency of the transcription factor Yin Yang 1 (YY1) as indicated by electrophoretic mobility shift assay (EMSA). Furthermore, we analyzed whether a higher expression of YY1 in the BLA of LAB mice, observed after CMS, contributed to the elevation of Crhr1. Indeed, overexpression of YY1 in the neuronal cell culture enhanced both Crhr1 expression and Crhr1 promoter activity. Finally, we estimated the effects of combininig CpG1 site-specific methylation with YY1 overexpression on Crhr1 promoter activity and tested whether in vitro overexpression of YY1 induced methylation of CpG1. Altogether, our data suggest that even a rigid genetic predisposition to low anxiety-related behavior could be rescued by environmental modification and provide evidence that the epigenetic regulation of Crhr1 expression in the BLA is a possible underlying mechanism behind

Planar Two-Loop Five-Parton Amplitudes from Numerical Unitarity

We compute a complete set of independent leading-color two-loop five-parton amplitudes in QCD. These constitute a fundamental ingredient for the next-to-next-to-leading order QCD corrections to three-jet production at hadron colliders. We show how to consistently consider helicity amplitudes with external fermions in dimensional regularization, allowing the application of a numerical variant of the unitarity approach. Amplitudes are computed by exploiting a decomposition of the integrand into master and surface terms that is independent of the parton type. Master integral coefficients are numerically computed in either finite-field or floating-point arithmetic and combined with known analytic master integrals. We recompute two-loop leading-color four-parton amplitudes as a check of our implementation. Results are presented for all independent four- and five-parton processes including contributions with massless closed fermion loops.Comment: v3: corrected wrong signs for five-gluon $N_f^2$ amplitudes with vanishing tree

The reservoir network: A new network topology for district heating and cooling

Thermal district networks are effective solutions to substitute fossil fuels with renewable energy sources for heating and cooling. Moreover, thermal networking of buildings allows energy efficiency to be further increased. The waste heat from cooling can be reused for heating in thermal district systems. Because of bidirectional energy flows between prosumers, thermal networks require new hydraulic concepts. In this work, we present a novel network topology for simultaneous heating and cooling: the reservoir network. The reservoir network is robust in operation due to hydraulic decoupling of transfer stations, integrates heat sources and heat sinks at various temperature levels and is flexible in terms of network expansion. We used Modelica simulations to compare the new single-pipe reservoir network to a basecase double-pipe network, taking yearly demand profiles of different building types for heating and cooling. The electric energy consumed by the heat pumps and circulations pumps differs between the reservoir and base case networks by less than 1%. However, if the reservoir network is operated with constant instead of variable mass flow rate, the total electrical consumption can increase by 48% compared to the base case. As with any other network topology, the design and control of such networks is crucial to achieving energy efficient operation. Investment costs for piping and trenching depend on the district layout and dimensioning of the network. If a ring layout is applied in a district, the reservoir network with its single-pipe configuration is more economical than other topologies. For a linear layout, the piping costs are slightly higher for the reservoir network than for the base case because of larger pipe diameters

Environmental manipulations generate bidirectional shifts in both behavior and gene regulation in a crossbred mouse model of extremes in trait anxiety

Although gene-environment interactions are known to significantly influence psychopathology related disease states, only few animal models cover both the genetic background and environmental manipulations. Therefore, we have taken advantage of the bidirectionally inbred high (HAB) and low (LAB) anxiety-related behavior mouse lines to generate HAB x LAB F1 hybrids that intrinsically carry both lines' genetic characteristics, and subsequently raised them in three different environments standard, enriched (EE) and chronic mild stress (CMS). Assessing genetic correlates of trait anxiety, we focused on two genes already known to play a role in HAB vs. LAB mice, corticotropin releasing hormone receptor type 1 (Crhr1) and high mobility group nucleosomal binding domain 3 (Hmgn3). While EE F1 mice showed decreased anxiety related and increased explorative behaviors compared to controls, CMS sparked effects in the opposite direction. However, environmental treatments affected the expression of the two genes in distinct ways. Thus, while expression ratios of Hmgn3 between the HAB- and LAB-specific alleles remained equal, total expression resembled the one observed in HAB vs. LAB mice, i.e., decreased after EE and increased after CMS treatment. On the other hand, while total expression of Crhr1 remained unchanged between the groups, the relative expression of HAB- and LAB-specific alleles showed a clear effect following the environmental modifications. Thus, the environmentally driven bidirectional shift of trait anxiety in this F1 model strongly correlated with Hmgn3 expression, irrespective of allele-specific expression patterns that retained the proportions of basic differential HAB vs. LAB expression, making this gene a match for environment-induced modifications. An involvement of Crhr1 in the bidirectional behavioral shift could, however, rather be due to different effects of the HAB- and LAB specific alleles described here. Both candidate genes therefore deserve attention in the complex regulation of anxiety-related phenotypes including environment-mediated effects

Leading-Color Two-Loop QCD Corrections for Three-Jet Production at Hadron Colliders

We present the complete set of leading-color two-loop contributions required to obtain next-to-next-to-leading-order (NNLO) QCD corrections to three-jet production at hadron colliders. We obtain analytic expressions for a generating set of finite remainders, valid in the physical region for three-jet production. The analytic continuation of the known Euclidean-region results is determined from a small set of numerical evaluations of the amplitudes. We obtain analytic expressions that are suitable for phenomenological applications and we present a C++ library for their efficient and stable numerical evaluation.Comment: Analytic results in ancillary files; link for numerical code in references. v3: matches the published versio