Evolution and Phylogeography of the North American genus Boechera (Brassicaceae)and the Evolution of Apomixis

Boechera is a North American genus of the Brassicaceae named after the Danish botanist Tyge Böcher who cytogenetically studied members of the genus in great detail. Until the end of the 20th century most species which belong today to Boechera were still included in the genus Arabis. Molecular studies in the late 1990s revealed that Arabis was polyphyletic and subsequently a majority of North American Arabis species was transferred into Boechera. Boechera inhabits a wide range of habitats and reproduces sexually as well as apomictic (asexual reproduction via seeds). The aims of the study presented inhere were (a) to reconstruct the phylogeographic history of the genus based on chloroplast DNA marker sequences and (b) to investigate the nrDNA ITS gene pool and reconstruct phylogenies based on nrDNA ITS and single copy gene introns. In the course of the experiments it appeared that eastern North American Boechera constitute different evolutionary lineages than the species centred in western North America. Hence the split of eastern and western North American Boechera species became a third subject (c). In our continental wide phylogeographic studies we detected a large amount of haplotype sharing indicating recurrent hybridisation on the one hand and non-differentiation of haplotypes since speciation on the other hand. We concluded that the chloroplast gene pool in Boechera pre-dates speciation in respect to the investigated markers. Unrelated from taxon identity we could show that the evolutionary lineages detected have a different phylogeographic history in terms of glacial refugia and recently recolonized areas. The study based on nrDNA ITS and introns of two single copy genes enabled us to obtain deeper insights into Boechera phylogeny and ITS type distribution across taxa. We could show that species specific lineages exist although the relationship among them is poorly resolved. Comparing gene tree topologies this indicates rapid speciation which probably happened in the second half of the quaternary. Hybrids could be identified by the comparison of the different marker systems together with chloroplast DNA types from an earlier study. The comparison of eastern and western North American Boechera based on DNA marker sequences showed that eastern North American Boechera represent two evolutionary lineages within the genus Boechera (cpDNA) or among the tribe Boechereae (nrDNA). We also included the Siberian taxa Borodinia and Boechera falcata in the analysis and could show that they were resolved within Boechera. The final task in the thesis was to unravel the origin of two apomict specific chromosomes (Het and Del). BAC-FISH analyses revealed that Het is a homologue of Boechera stricta linkage group 1 and Del appears only in 15 chromosome apomicts and is a fragment of Het. The thesis presented inhere offers deeper insights into the evolution of this complex genus and offers a good basis for ongoing and future research projects dealing with evolution and expression of apomixis as well as genome evolution in Boechera. CD mit großem Anhang erhältlich bei Verfasserin Email: [email protected]

The effect of thermal non-equilibrium on kinetic nucleation

Nucleation is considered to be the first step in dust and cloud formation in the atmospheres of asymptotic giant branch (AGB) stars, exoplanets, and brown dwarfs. In these environments dust and cloud particles grow to macroscopic sizes when gas phase species condense onto cloud condensation nuclei (CCNs). Understanding the formation processes of CCNs and dust in AGB stars is important because the species that formed in their outflows enrich the interstellar medium. Although widely used, the validity of chemical and thermal equilibrium conditions is debatable in some of these highly dynamical astrophysical environments. We aim to derive a kinetic nucleation model that includes the effects of thermal non-equilibrium by adopting different temperatures for nucleating species, and to quantify the impact of thermal non-equilibrium on kinetic nucleation. Forward and backward rate coefficients are derived as part of a collisional kinetic nucleation theory ansatz. The endothermic backward rates are derived from the law of mass action in thermal non-equilibrium. We consider elastic collisions as thermal equilibrium drivers. For homogeneous TiO2 nucleation and a gas temperature of 1250 K, we find that differences in the kinetic cluster temperatures as small as 20 K increase the formation of larger TiO2 clusters by over an order of magnitude. An increase in cluster temperature of around 20 K at gas temperatures of 1000 K can reduce the formation of a larger TiO2 cluster by over an order of magnitude. Our results confirm and quantify the prediction of previous thermal non-equilibrium studies. Small thermal non-equilibria can cause a significant change in the synthesis of larger clusters. Therefore, it is important to use kinetic nucleation models that include thermal non-equilibrium to describe the formation of clusters in environments where even small thermal non-equilibria can be present.Comment: 13 pages, 4 figure

Exploring Influences on Theory of Mind Impairment in Opioid Dependent Patients

Theory of mind (ToM) is an aspect of social cognition impaired in different addictive disorders, including opioid addiction. This study aimed at replicating ToM deficits in opioid dependent patients undergoing opioid maintenance treatment (OMT) and exploring the influence of substance use related variables, executive functions and childhood maltreatment on ToM in opioid dependent patients. 66 opioid dependent patients were tested using the Movie for Assessment of Social Cognition (MASC) and compared with the data of healthy controls. Furthermore, the opioid dependent patients underwent testing for executive functions and filled in the Childhood Trauma Questionnaire (CTQ). Performance on the MASC was significantly poorer in the opioid dependence group than in the control group, even when recent additional drug use and psychiatric comorbidities were controlled for. No correlations were found between ToM and substance use related factors. Aspects of ToM performance in opioid dependent patients correlated significantly with different EF domains. ToM correlated significantly with the CTQ scales for physical maltreatment. The results confirm impaired ToM in opioid dependent patients and highlight executive functions and childhood maltreatment as influential factors. The lack of associations between ToM and substance use related variables and the association with childhood maltreatment suggest that ToM impairments might be a risk factor predating substance abuse.Peer Reviewe

The role of hydrogen in a greenhouse gas-neutral energy supply system in Germany

Hydrogen is widely considered to play a pivotal role in successfully transforming the German energy system, but the German government\u27s current “National Hydrogen Strategy” does not specify how hydrogen utilization, production, storage or distribution will be implemented. Addressing key uncertainties for the German energy system\u27s path to greenhouse gas-neutrality, this paper examines hydrogen in different scenarios. This analysis aims to support the concretization of the German hydrogen strategy. Applying a European energy supply model with strong interactions between the conversion sector and the hydrogen system, the analysis focuses on the requirements for geological hydrogen storages and their utilization over the course of a year, the positioning of electrolyzers within Germany, and the contributions of hydrogen transport networks to balancing supply and demand. Regarding seasonal hydrogen storages, the results show that hydrogen storage facilities in the range of 42 TWhH2 to 104 TWhH2 are beneficial to shift high electricity generation volumes from onshore wind in spring and fall to winter periods with lower renewable supply and increased electricity and heat demands. In 2050, the scenario results show electrolyzer capacities between 41 GWel and 75 GWel in Germany. Electrolyzer sites were found to follow the low-cost renewable energy potential and are concentrated on the North Sea and Baltic Sea coasts with their high wind yields. With respect to a hydrogen transport infrastructure, there were two robust findings: One, a domestic German hydrogen transport network connecting electrolytic hydrogen production sites in northern Germany with hydrogen demand hubs in western and southern Germany is economically efficient. Two, connecting Germany to a European hydrogen transport network with interconnection capacities between 18 GWH2 and 58 GWH2 is cost-efficient to meet Germany\u27s substantial hydrogen demand

Adding complexity to complexity: Gene family evolution in polyploids

Comparative genomics of non-model organisms has resurrected whole genome duplication (WGD) from being viewed as a somewhat obscure process that happens in plants to a primary driver of eukaryotic diversification. The shadow of past ploidy increases has left a strong signature of duplicated genes organized into gene families, even in small genomes that have undergone effectively complete rediploidization. Nevertheless, despite continually advancing technologies and bioinformatics pipelines, resolving the fate of duplicate genes remains a substantial challenge. For example, many important recognition processes are driven not only by allelic expansion through retention of duplicates but also by diversification and copy number variation. This creates technical difficulties with assembly to reference genomes and accurate interpretation of homology. Thus, relatively little is known about the impacts of recent polyploidization and hybridization on the evolution of gene families under selective forces that maintain diversity, such as balancing selection. Here we use a complex of species and ploidy levels in the genus Arabidopsis (A. lyrata and A. arenosa) as a model to investigate the evolutionary dynamics of a large and complicated gene family known to be under strong balancing selection: the receptor-like kinases, which include the female component of genetically controlled self-incompatibility. Specifically, we question: (1) How does diversity of S-receptor kinase (SRK) alleles in tetraploids compare to that in their close diploid relatives? (2) Is there increased trans-specific polymorphism (i.e., sharing of alleles that transcend speciation, characteristic of balancing selection) in tetraploids compared to diploids due to the higher number of copies they carry? (3) Do these highly variable loci show evidence of introgression among extant species/ploidy levels within or outside known zones of hybridization? (4) Is there evidence for copy number variation among paralogs? We use this example to highlight specific issues to consider when interpreting gene family evolution, particularly in relation to polyploids but also more generally in diploids. We conclude with recommendations for strategies to address the challenges of resolving such complex loci in the future, using advances in deep sequencing approaches

Alcohol does not influence trust in others or oxytocin, but increases positive affect and risk‑taking: a randomized, controlled, within‑subject trial

Background: Alcohol consumption to facilitate social interaction is an important drinking motive. Here, we tested whether alcohol influences trust in others via modulation of oxytocin and/or androgens. We also aimed at confirming previously shown alcohol effects on positive affect and risk-taking, because of their role in facilitating social interaction. Methods: This randomized, controlled, within-subject, parallel group, alcohol-challenge experiment investigated the effects of alcohol (versus water, both mixed with orange juice) on perceived trustworthiness via salivary oxytocin (primary and secondary endpoint) as well as testosterone, dihydrotestosterone, positive affect, and risk-taking (additional endpoints). We compared 56 male participants in the alcohol condition (1.07 ± 0.18 per mille blood alcohol concentration) with 20 in the control condition. Results: The group (alcohol versus control condition) × time (before [versus during] versus after drinking) interactions were not significantly associated with perceived trustworthiness (η2 < 0.001) or oxytocin (η2 = 0.003). Bayes factors provided also substantial evidence for the absence of these effects (BF01 = 3.65; BF01 = 7.53). The group × time interactions were related to dihydrotestosterone (η2 = 0.018 with an increase in the control condition) as well as positive affect and risk-taking (η2 = 0.027 and 0.007 with increases in the alcohol condition), but not significantly to testosterone. Discussion: The results do not verify alcohol effects on perceived trustworthiness or oxytocin in male individuals. However, they indicate that alcohol (versus control) might inhibit an increase in dihydrotestosterone and confirm that alcohol amplifies positive affect and risk-taking. This provides novel mechanistic insight into social facilitation as an alcohol-drinking motive

On the origin and evolutionary consequences of gene body DNA methylation

In plants, CG DNA methylation is prevalent in the transcribed regions of many constitutively expressed genes (gene body methylation; gbM), but the origin and function of gbM remain unknown. Here we report the discovery that Eutrema salsugineum has lost gbM from its genome, to our knowledge the first instance for an angiosperm. Of all known DNA methyltransferases, only CHROMOMETHYLASE 3 (CMT3) is missing from E. salsugineum Identification of an additional angiosperm, Conringia planisiliqua, which independently lost CMT3 and gbM, supports that CMT3 is required for the establishment of gbM. Detailed analyses of gene expression, the histone variant H2A.Z, and various histone modifications in E. salsugineum and in Arabidopsis thaliana epigenetic recombinant inbred lines found no evidence in support of any role for gbM in regulating transcription or affecting the composition and modification of chromatin over evolutionary timescales

How Do I Look? Body Image Perceptions among University Students from England and Denmark

This study examined differences in body image perception between university students in two European countries, United Kingdom and Denmark. A total of 816 British and 548 Danish university students participated in a cross-sectional survey. A self-administered questionnaire assessed socio-demographic information, body image perception (as “too thin”, “just right” or “too fat”), and the association of related factors with body image perception (nutrition behaviour, social support, perceived stressors and quality of life). The proportions of students who perceived themselves as “too thin”, “just right”, or “too fat” were 8.6%, 37.7%, and 53.7% respectively. Multi-factorial logistic regression analysis showed that students who perceived themselves as “too fat” were more likely to be from the British university, to be females, to be older than 30 years, to report stress due to their financial situation and were less likely to have a high quality of life. The findings highlight the need for interventions with focus on healthy food choices whilst acknowledging financial stressors and quality of life

A Continental-Wide Perspective: The Genepool of Nuclear Encoded Ribosomal DNA and Single-Copy Gene Sequences in North American Boechera (Brassicaceae)

74 of the currently accepted 111 taxa of the North American genus Boechera (Brassicaceae) were subject to pyhlogenetic reconstruction and network analysis. The dataset comprised 911 accessions for which ITS sequences were analyzed. Phylogenetic analyses yielded largely unresolved trees. Together with the network analysis confirming this result this can be interpreted as an indication for multiple, independent, and rapid diversification events. Network analyses were superimposed with datasets describing i) geographical distribution, ii) taxonomy, iii) reproductive mode, and iv) distribution history based on phylogeographic evidence. Our results provide first direct evidence for enormous reticulate evolution in the entire genus and give further insights into the evolutionary history of this complex genus on a continental scale. In addition two novel single-copy gene markers, orthologues of the Arabidopsis thaliana genes At2g25920 and At3g18900, were analyzed for subsets of taxa and confirmed the findings obtained through the ITS data

The ReCoDe addiction research consortium:Losing and regaining control over drug intake-Findings and future perspectives

Substance use disorders (SUDs) are seen as a continuum ranging from goal-directed and hedonic drug use to loss of control over drug intake with aversive consequences for mental and physical health and social functioning. The main goals of our interdisciplinary German collaborative research centre on Losing and Regaining Control over Drug Intake (ReCoDe) are (i) to study triggers (drug cues, stressors, drug priming) and modifying factors (age, gender, physical activity, cognitive functions, childhood adversity, social factors, such as loneliness and social contact/interaction) that longitudinally modulate the trajectories of losing and regaining control over drug consumption under real-life conditions. (ii) To study underlying behavioural, cognitive and neurobiological mechanisms of disease trajectories and drug-related behaviours and (iii) to provide non-invasive mechanism-based interventions. These goals are achieved by: (A) using innovative mHealth (mobile health) tools to longitudinally monitor the effects of triggers and modifying factors on drug consumption patterns in real life in a cohort of 900 patients with alcohol use disorder. This approach will be complemented by animal models of addiction with 24/7 automated behavioural monitoring across an entire disease trajectory; i.e. from a naïve state to a drug-taking state to an addiction or resilience-like state. (B) The identification and, if applicable, computational modelling of key molecular, neurobiological and psychological mechanisms (e.g., reduced cognitive flexibility) mediating the effects of such triggers and modifying factors on disease trajectories. (C) Developing and testing non-invasive interventions (e.g., Just-In-Time-Adaptive-Interventions (JITAIs), various non-invasive brain stimulations (NIBS), individualized physical activity) that specifically target the underlying mechanisms for regaining control over drug intake. Here, we will report on the most important results of the first funding period and outline our future research strategy.</p