Publications by authors named "Katharina Schmid"

71 Publications

Dynamic contact effects: Individuals' positive and negative contact history influences intergroup contact effects in a behavioral game.

J Pers Soc Psychol 2021 Sep 16. Epub 2021 Sep 16.

Faculty of Psychology.

Positive contact between members of different groups reduces prejudice and increases cooperation, findings known as intergroup contact effects. Yet in real-world settings not only positive, but also negative intergroup contact occurs, which have opposing effects. To date little is known about whether and how an individual's valenced history of intergroup contact influences contact effects and how this dynamic change happens during specific instances of intergroup contact. A pilot study examined the psychological impact of a novel paradigm to assess intergroup contact using a behavioral game. We then conducted two studies, which allowed us to observe a sequence of up to 23 in- and outgroup interactions and their behavioral outcomes in a continuous prisoner's dilemma behavioral game ( = 116, 2,668 interactions; = 89, 1,513 interactions). As expected, participants showed a clear ingroup bias in expectations and cooperation. Furthermore, the quality of contact history moderated contact effects. Specifically, intergroup contact following a positive history of intergroup contact had a stronger effect on intergroup expectations than contact following a negative history thereof. Findings are discussed in view of the importance of considering the valenced history of intergroup contact, as well as new research questions on intergroup contact that can be addressed with this novel contact paradigm. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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http://dx.doi.org/10.1037/pspi0000374DOI Listing
September 2021

Adolescent development of interethnic attitudes following a social intervention to increase intergroup contact: The moderating role of affective forecasting.

Dev Psychol 2021 Jun;57(6):1000-1017

University of Oxford.

This longitudinal, quasi-experimental field study investigated affective forecasting as a moderator of positive intergroup contact effects among adolescents. We also examined a novel mediating mechanism that underlies this effect, namely accuracy of perceived outgroup willingness for intergroup contact. Three annual waves of survey data were used from 1,169 adolescents (Mage = 13.88 at Wave 1; 50% girls; 66% White British, 44% Asian British) whose schools were merged, in a unique intervention that resulted in one school where ethnic groups were evenly mixed (i.e., balanced school) and two White British majority schools (i.e., majority skewed schools). Results showed that positive intergroup contact and attitudes improved more in the balanced school than in the majority skewed schools. In all schools, change in adolescents' positive intergroup contact predicted change in positive intergroup attitudes indirectly via (a) increased accuracy of perceived outgroup willingness for contact and (b) reduced intergroup anxiety. Indirect effects via accuracy of perceived contact willingness were stronger for adolescents who made more negative affective forecasts than for other adolescents. These moderated mediation effects were stronger in the balanced school than in the majority skewed schools. Thus, more balanced ethnic mixing in schools seemed to directly enhance positive intergroup relations and attitudes for all adolescents, but to particularly benefit adolescents who made more negative affective forecasts about positive contact before the school merger. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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http://dx.doi.org/10.1037/dev0001194DOI Listing
June 2021

Structural basis for PRC2 decoding of active histone methylation marks H3K36me2/3.

Elife 2020 11 19;9. Epub 2020 Nov 19.

Max Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Martinsried, Germany.

Repression of genes by Polycomb requires that PRC2 modifies their chromatin by trimethylating lysine 27 on histone H3 (H3K27me3). At transcriptionally active genes, di- and tri-methylated H3K36 inhibit PRC2. Here, the cryo-EM structure of PRC2 on dinucleosomes reveals how binding of its catalytic subunit EZH2 to nucleosomal DNA orients the H3 N-terminus via an extended network of interactions to place H3K27 into the active site. Unmodified H3K36 occupies a critical position in the EZH2-DNA interface. Mutation of H3K36 to arginine or alanine inhibits H3K27 methylation by PRC2 on nucleosomes . Accordingly, H3K36A and H3K36R mutants show reduced levels of H3K27me3 and defective Polycomb repression of HOX genes. The relay of interactions between EZH2, the nucleosomal DNA and the H3 N-terminus therefore creates the geometry that permits allosteric inhibition of PRC2 by methylated H3K36 in transcriptionally active chromatin.
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http://dx.doi.org/10.7554/eLife.61964DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7725500PMC
November 2020

Strategic experimentation with asymmetric players.

Econ Theory 2020 22;69(4):1147-1175. Epub 2019 Apr 22.

Gymnasium Bad Aibling Westendstraße 6A, 83043 Bad Aibling, Germany.

We examine a two-player game with two-armed exponential bandits à la (Keller et al. in Econometrica 73:39-68, 2005), where players operate different technologies for exploring the risky option. We characterise the set of Markov perfect equilibria and show that there always exists an equilibrium in which the player with the inferior technology uses a cut-off strategy. All Markov perfect equilibria imply the same of experimentation but differ with respect to the expected speed of the resolution of uncertainty. If and only if the degree of asymmetry between the players is high enough, there exists a Markov perfect equilibrium in which both players use cut-off strategies. Whenever this equilibrium exists, it welfare dominates all other equilibria. This contrasts with the case of symmetric players, where there never exists a Markov perfect equilibrium in cut-off strategies.
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http://dx.doi.org/10.1007/s00199-019-01193-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357687PMC
April 2019

When good for business is not good enough: Effects of pro-diversity beliefs and instrumentality of diversity on intergroup attitudes.

PLoS One 2020 1;15(6):e0234179. Epub 2020 Jun 1.

Faculty of Psychology, FernUniversität in Hagen, Hagen, Germany.

Instrumentality-based pro-diversity beliefs (i.e., beliefs that diverse groups outperform homogenous groups in terms of group functioning) have been shown to improve intergroup attitudes. However, such valuing of diversity due to its expected instrumentality holds the risk that outgroups may be devalued in situations when diversity ends up being detrimental to group functioning. Across four experiments, we studied the interplay between instrumentality-based pro-diversity beliefs, actual instrumentality of ethnic diversity, and outgroup attitudes. Our results do not reveal a robust interaction effect between instrumentality-based pro-diversity beliefs and actual instrumentality of diverse groups. Some evidence, however, supports the assumption that instrumentality-based pro-diversity beliefs yielded a weaker positive or even a negative effect on ethnic outgroup attitudes when ethnic diversity was perceived as non-instrumental (i.e., when diversity was perceived as having a negative impact on group functioning). Theoretical contributions, practical implications, and directions for future research are discussed.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0234179PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7263624PMC
August 2020

Investigation of microbial cell deformability by filter cake compressibility using ultrafiltration membranes.

Colloids Surf B Biointerfaces 2020 Jan 7;185:110626. Epub 2019 Nov 7.

Sartorius Stedim Biotech GmbH, August-Spindler-Straße 11, 37079 Goettingen, Germany.

This study presents the investigation of deformability of various microbial cells in terms of filter cake compressibility during cake filtration using ultrafiltration membranes in dead-end mode. The examined microbial cells include mycoplasma, Gram-positive and Gram-negative bacteria, and Pseudomonas aeruginosa phage PP7. Polystyrene particles were used as an incompressible reference. The compressibility results were correlated to the deformability of a microbial cell, induced by its cell envelope. To determine the deformability of the different microbial cells under different process conditions, their cake resistance was measured under varying pressures from 10 to 250 kPa and temperatures from 2 to 35 °C. In addition, the influence of different culture media on the cell properties of Acholeplasma laidlawii and its behavior under different pressure and temperature was determined. The results of the pressure and temperature experiments revealed that Gram-positive S. epidermidis was found to be relatively stiff due to the thickness of the peptidoglycan layer, under different pressure and temperature conditions. No significant increase of the specific cake resistance of S. epidermidis could be determined. B. diminuta however showed a high deformation tendency when the pressure was increased indicating relatively soft cells. Mycoplasma A. laidlawii cells cultivated in three different media showed a different, but significant, effect of pressure and temperature.
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http://dx.doi.org/10.1016/j.colsurfb.2019.110626DOI Listing
January 2020

Influence of Preoperative Magnetic Resonance Imaging on Surgical Decision Making for Patients with Acute Traumatic Cervical Spinal Cord Injury: A Survey Among Experienced Spine Surgeons.

World Neurosurg 2019 Nov 9;131:e586-e592. Epub 2019 Aug 9.

Department of Neurosurgery, BG Trauma Center Murnau, Murnau, Germany.

Objective: Early decompression after acute spinal cord injury (SCI) is recommended. Acute care is crucial, but optimal management is unclear. The aim of this study was to investigate the role of preoperative magnetic resonance imaging (MRI) in addition to computed tomography (CT) in surgical decision making for acute cervical SCI.

Methods: All patients with cervical SCI between 2008 and 2016 who had preoperative CT and MRI (n = 63) at the Trauma Center Murnau, Germany, were included. We administered a survey to 10 experienced spine surgeons (5 neurosurgeons, 5 trauma surgeons) regarding the surgical management. First, the surgeons were shown clinical information and CT scans. Two months later, the survey was repeated with additional MRI. Corresponding percentages of change and agreement were obtained for each rater and survey item. Finally, results from both parts of the survey were compared with the definitive treatment option (i.e., real-world decision).

Results: MRI modified surgical timing in a median of 41% of patients (interquartile range 38%-56%). In almost every fifth patient (17%), no surgery would have been indicated with CT alone. The advocated surgical approach was changed in almost half of patients (median 48%, interquartile range 33%-49%). Surgically addressed levels were changed in a median of 57% of patients (interquartile range 56%-60%). MRI led to higher agreement with the real-world decision concerning addressed levels (median 35% vs. 73%), timing (median 51% vs. 57%), and approach (median 44% vs. 65%).

Conclusions: Preoperative MRI influenced surgical decision making substantially in our cohort and has become a new standard for patients with cervical SCI in our institution if medically possible.
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http://dx.doi.org/10.1016/j.wneu.2019.08.009DOI Listing
November 2019

Indirect contact predicts direct contact: Longitudinal evidence and the mediating role of intergroup anxiety.

J Pers Soc Psychol 2019 Feb 1;116(2):277-295. Epub 2018 Nov 1.

Department of Experimental Psychology, University of Oxford.

Although the effects of direct and indirect forms of contact on intergroup relations are well documented, little is known about their longitudinal co-development. Based on the social-psychological literature, we hypothesize that indirect contact predicts future direct contact by reducing intergroup anxiety. Across five longitudinal studies (Study 1: German adults, N = 560; Study 2: German, Dutch, and Swedish school students, N = 6,600; Study 3: Northern Irish children, N = 1,593; Study 4: Northern Irish adults, N = 404; Study 5: German adults, N = 735), we systematically examined this effect, and further tested the mediating role of intergroup anxiety in Studies 3 to 5. Cross-lagged models provided consistent evidence for the positive effect of indirect contact on future direct contact, whereas a reduction in intergroup anxiety mediates this effect in most models. Results highlight the importance of indirect contact, which has the potential to increase direct contact, and thus promote social cohesion in diverse contexts, over time. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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http://dx.doi.org/10.1037/pspi0000146DOI Listing
February 2019

Ethnic Diversity, Inter-group Attitudes and Countervailing Pathways of Positive and Negative Inter-group Contact: An Analysis Across Workplaces and Neighbourhoods.

Soc Indic Res 2018;136(2):719-749. Epub 2017 Jan 28.

3University of Oxford, South Parks Road, Oxford, OX1 3UD UK.

This study advances the current literature investigating the relationship between contextual out-group exposure, inter-group attitudes and the role of inter-group contact. Firstly, it introduces the concept of contact-valence into this relationship; that is, whether contact is experienced positively or negatively. Secondly, it presents a comparative analysis of how processes of out-group exposure and frequency of (valenced) contact affect prejudice across both neighbourhoods and workplaces. Applying path analysis modelling to a nationally-representative sample of white British individuals in England, we demonstrate, across both contexts, that increasing out-group exposure is associated with higher rates of both positively- and negatively-valenced contact. This results in exposure exhibiting both positive negative indirect associations with prejudice via more frequent inter-group mixing. These countervailing contact-pathways help explain how out-group exposure is associated with inter-group attitudes. In neighbourhoods, increasing numbers of individuals experiencing positive-contact suppress an otherwise negative effect of neighbourhood diversity (driven partly by increasing numbers of individuals reporting negative contact). Across workplaces the effect differs such that increasing numbers of individuals experiencing negative-contact suppress an otherwise positive effect of workplace diversity (driven largely by increasing numbers of individuals experiencing positive contact).
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http://dx.doi.org/10.1007/s11205-017-1570-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5842268PMC
January 2017

The "Wallpaper Effect" Revisited: Divergent Findings on the Effects of Intergroup Contact on Attitudes in Diverse Versus Nondiverse Contexts.

Pers Soc Psychol Bull 2017 Sep 14;43(9):1268-1283. Epub 2017 Jun 14.

2 University of Oxford, UK.

This article reexamines the so-called "wallpaper effect" of intergroup contact, which contends that for minority group members living in areas more densely populated by majority group members, intergroup contact fails to reduce prejudice. We tested this claim in five studies, using data from five countries, two types of contexts, a range of measures, and involving different minority versus majority groups. Using multilevel cross-level interaction models, we considered whether effects of contact on outgroup attitudes were moderated by relative outgroup size. Results failed to replicate the previously reported findings, revealing, by and large, nonsignificant cross-level moderation effects; instead, we witnessed consistent positive contact effects on attitudes. Findings are discussed against the backdrop of recent research on the consequences of diversity, as well as context-based considerations regarding minority versus majority constellations. We also discuss some exceptions to our findings that emerged for some respondent groups and contexts across the five studies.
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http://dx.doi.org/10.1177/0146167217711929DOI Listing
September 2017

Intergroup Contact and Social Change: Implications of Negative and Positive Contact for Collective Action in Advantaged and Disadvantaged Groups.

Pers Soc Psychol Bull 2017 01;43(1):121-136

1 University of Oxford, UK.

Previous research has shown that (a) positive intergroup contact with an advantaged group can discourage collective action among disadvantaged-group members and (b) positive intergroup contact can encourage advantaged-group members to take action on behalf of disadvantaged outgroups. Two studies investigated the effects of negative as well as positive intergroup contact. Study 1 ( n = 482) found that negative but not positive contact with heterosexual people was associated with sexual-minority students' engagement in collective action (via group identification and perceived discrimination). Among heterosexual students, positive and negative contacts were associated with, respectively, more and less LGB (lesbian, gay, bisexual) activism. Study 2 ( N = 1,469) found that only negative contact (via perceived discrimination) predicted LGBT (lesbian, gay, bisexual, and transgender) students' collective action intentions longitudinally while only positive contact predicted heterosexual/cisgender students' LGBT activism. Implications for the relationship between intergroup contact, collective action, and social change are discussed.
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http://dx.doi.org/10.1177/0146167216676478DOI Listing
January 2017

HSP90 is necessary for the ACK1-dependent phosphorylation of STAT1 and STAT3.

Cell Signal 2017 11 21;39:9-17. Epub 2017 Jul 21.

Department of Toxicology, University Medical Center, Obere Zahlbacher Str. 67, 55131 Mainz, Germany. Electronic address:

Signal transducers and activators of transcription (STATs) are latent, cytoplasmic transcription factors. Janus kinases (JAKs) and activated CDC42-associated kinase-1 (ACK1/TNK2) catalyse the phosphorylation of STAT1 and the expression of its target genes. Here we demonstrate that catalytically active ACK1 promotes the phosphorylation and nuclear accumulation of STAT1 in transformed kidney cells. These processes are associated with STAT1-dependent gene expression and an interaction between endogenous STAT1 and ACK1. Moreover, the E3 ubiquitin ligase seven-in-absentia homolog-2 (SIAH2), which targets ACK1 through valine-909 for proteasomal degradation, attenuates the ACK1-STAT1 signalling node. We further show that ACK1 promotes the phosphorylation and nuclear accumulation of STAT3 in cultured cells and that the levels of ACK1 correlate positively with the levels of tyrosine phosphorylated STAT3 in primary lung adenocarcinoma (ADC) cells. Global analysis of ACK1 interaction partners validated the interaction of ACK1 with heat shock protein 90 (HSP90α/β). Inhibition of this chaperone with the novel drug Onalespib (AT13387) demonstrates that HSP90 is an upstream regulator of the ACK1-dependent phosphorylation of STAT1 and STAT3. In addition to these molecular insights, our data offer a pharmacological strategy to control the ACK1-STAT signalling axis.
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http://dx.doi.org/10.1016/j.cellsig.2017.07.014DOI Listing
November 2017

LC-MS Analysis of Methylated RNA.

Methods Mol Biol 2017 ;1562:3-18

Institute of Pharmacy and Biochemistry, Johannes Gutenberg-University of Mainz, Staudingerweg 5, 55099, Mainz, Germany.

The detection and quantification of methylated RNA can be beneficial to understand certain cellular regulation processes such as transcriptional modulation of gene expression, immune response, or epigenetic alterations. Therefore, it is necessary to have methods available, which are extremely sensitive and accurate, for instance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we describe the preparation of RNA samples by enzymatic hydrolysis and the subsequent analysis of ribonucleosides by LC-MS/MS via NLS (Neutral loss scan) and DMRM (Dynamic multiple reaction monitoring). Also, we provide variations of these methods including chromatographic techniques and different kinds of quantification.
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http://dx.doi.org/10.1007/978-1-4939-6807-7_1DOI Listing
February 2018

Alkyne-Functionalized Coumarin Compound for Analytic and Preparative 4-Thiouridine Labeling.

Bioconjug Chem 2017 04 15;28(4):1123-1134. Epub 2017 Mar 15.

Institute of Pharmacy and Biochemistry, Johannes-Gutenberg University Mainz , Staudingerweg 5, D-55128 Mainz, Germany.

Bioconjugation of RNA is a dynamic field recently reinvigorated by a surge in research on post-transcriptional modification. This work focuses on the bioconjugation of 4-thiouridine, a nucleoside that occurs as a post-transcriptional modification in bacterial RNA and is used as a metabolic label and for cross-linking purposes in eukaryotic RNA. A newly designed coumarin compound named 4-bromomethyl-7-propargyloxycoumarin (PBC) is introduced, which exhibits remarkable selectivity for 4-thiouridine. Bearing a terminal alkyne group, it is conductive to secondary bioconjugation via "click chemistry", thereby offering a wide range of preparative and analytical options. We applied PBC to quantitatively monitor the metabolic incorporation of sU as a label into RNA and for site-specific introduction of a fluorophore into bacterial tRNA at position 8, allowing the determination of its binding constant to an RNA-modification enzyme.
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http://dx.doi.org/10.1021/acs.bioconjchem.7b00035DOI Listing
April 2017

mA modulates neuronal functions and sex determination in Drosophila.

Nature 2016 12 30;540(7632):242-247. Epub 2016 Nov 30.

Institute of Molecular Biology (IMB), 55128 Mainz, Germany.

N-methyladenosine RNA (mA) is a prevalent messenger RNA modification in vertebrates. Although its functions in the regulation of post-transcriptional gene expression are beginning to be unveiled, the precise roles of mA during development of complex organisms remain unclear. Here we carry out a comprehensive molecular and physiological characterization of the individual components of the methyltransferase complex, as well as of the YTH domain-containing nuclear reader protein in Drosophila melanogaster. We identify the member of the split ends protein family, Spenito, as a novel bona fide subunit of the methyltransferase complex. We further demonstrate important roles of this complex in neuronal functions and sex determination, and implicate the nuclear YT521-B protein as a main mA effector in these processes. Altogether, our work substantially extends our knowledge of mA biology, demonstrating the crucial functions of this modification in fundamental processes within the context of the whole animal.
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http://dx.doi.org/10.1038/nature20568DOI Listing
December 2016

Interaction of the Nitrogen Regulatory Protein GlnB (P) with Biotin Carboxyl Carrier Protein (BCCP) Controls Acetyl-CoA Levels in the Cyanobacterium sp. PCC 6803.

Front Microbiol 2016 26;7:1700. Epub 2016 Oct 26.

Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen Tübingen, Germany.

The family of P signal transduction proteins (members GlnB, GlnK, NifI) plays key roles in various cellular processes related to nitrogen metabolism at different functional levels. Recent studies implied that P proteins may also be involved in the regulation of fatty acid metabolism, since GlnB proteins from Proteobacteria and from were shown to interact with biotin carboxyl carrier protein (BCCP) of acetyl-CoA carboxylase (ACC). In case of ACCase, this interaction reduces the k of acetyl-CoA carboxylation, which should have a marked impact on the acetyl-CoA metabolism. In this study we show that the P protein of a unicellular cyanobacterium inhibits the biosynthetic activity of ACC and also interacts with cyanobacterial BCCP in an ATP and 2-oxoglutarate dependent manner. In a P mutant strain of strain PCC 6803, the lacking control leads to reduced acetyl-CoA levels, slightly increased levels of fatty acids and formation of lipid bodies as well as an altered fatty acid composition.
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http://dx.doi.org/10.3389/fmicb.2016.01700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5080355PMC
October 2016

Comprehensive DNA methylation analysis of the Aedes aegypti genome.

Sci Rep 2016 11 2;6:36444. Epub 2016 Nov 2.

Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120 Heidelberg, Germany.

Aedes aegypti mosquitoes are important vectors of viral diseases. Mosquito host factors play key roles in virus control and it has been suggested that dengue virus replication is regulated by Dnmt2-mediated DNA methylation. However, recent studies have shown that Dnmt2 is a tRNA methyltransferase and that Dnmt2-dependent methylomes lack defined DNA methylation patterns, thus necessitating a systematic re-evaluation of the mosquito genome methylation status. We have now searched the Ae. aegypti genome for candidate DNA modification enzymes. This failed to reveal any known (cytosine-5) DNA methyltransferases, but identified homologues for the Dnmt2 tRNA methyltransferase, the Mettl4 (adenine-6) DNA methyltransferase, and the Tet DNA demethylase. All genes were expressed at variable levels throughout mosquito development. Mass spectrometry demonstrated that DNA methylation levels were several orders of magnitude below the levels that are usually detected in organisms with DNA methylation-dependent epigenetic regulation. Furthermore, whole-genome bisulfite sequencing failed to reveal any evidence of defined DNA methylation patterns. These results suggest that the Ae. aegypti genome is unmethylated. Interestingly, additional RNA bisulfite sequencing provided first evidence for Dnmt2-mediated tRNA methylation in mosquitoes. These findings have important implications for understanding the mechanism of Dnmt2-dependent virus regulation.
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http://dx.doi.org/10.1038/srep36444DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5090363PMC
November 2016

Developmental Dynamics of Intergroup Contact and Intergroup Attitudes: Long-Term Effects in Adolescence and Early Adulthood.

Child Dev 2016 09;87(5):1466-78

Örebro University.

Intergroup contact represents a powerful way to improve intergroup attitudes and to overcome prejudice and discrimination. However, long-term effects of intergroup contact that consider social network dynamics have rarely been studied at a young age. Study 1 validated an optimized social network approach to investigate intergroup contact (N = 6,457; Mage  = 14.91 years). Study 2 explored the developmental trajectories of intergroup contact by applying this validated network approach in a cross-sequential design (four-cohort-four-wave; N = 3,815; 13-26 years). Accelerated growth curve models showed that contact predicts the development of attitudes in adolescence, whereas acquired attitudes buffer against decreasing contact in adulthood. Findings highlight the potential of social network analysis and the developmental importance of early intergroup contact experiences.
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http://dx.doi.org/10.1111/cdev.12598DOI Listing
September 2016

Analysis of RNA modifications by liquid chromatography-tandem mass spectrometry.

Methods 2016 09 25;107:48-56. Epub 2016 Mar 25.

Institute of Pharmacy and Biochemistry, Johannes Gutenberg-University of Mainz, Staudingerweg 5, 55099 Mainz, Germany. Electronic address:

The analysis of RNA modifications is of high importance in order to address a wide range of biological questions. Therefore, a highly sensitive and accurate method such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) has to be available. By using different LC-MS/MS procedures, it is not only possible to quantify very low amounts of RNA modifications, but also to detect probably unknown modified nucleosides. For these cases the dynamic multiple reaction monitoring and the neutral loss scan are the most common techniques. Here, we provide the whole workflow for analyzing RNA samples regarding their modification content. This includes an equipment list, the preparation of required solutions/enzymes and the creation of an internal standard or nucleoside stocks for internal or external calibration. Furthermore, we describe the preparation of RNA samples for the subsequent LC-MS/MS analysis and the corresponding analysis process.
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http://dx.doi.org/10.1016/j.ymeth.2016.03.019DOI Listing
September 2016

Intergroup Contact Effects via Ingroup Distancing among Majority and Minority Groups: Moderation by Social Dominance Orientation.

PLoS One 2016 11;11(1):e0146895. Epub 2016 Jan 11.

Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.

Five studies tested whether intergroup contact reduces negative outgroup attitudes through a process of ingroup distancing. Based on the deprovincialization hypothesis and Social Dominance Theory, we hypothesized that the indirect effect of cross-group friendship on outgroup attitudes via reduced ingroup identification is moderated by individuals' Social Dominance Orientation (SDO), and occurs only for members of high status majority groups. We tested these predictions in three different intergroup contexts, involving conflictual relations between social groups in Germany (Study 1; N = 150; longitudinal Study 2: N = 753), Northern Ireland (Study 3: N = 160; Study 4: N = 1,948), and England (Study 5; N = 594). Cross-group friendship was associated with reduced ingroup identification and the link between reduced ingroup identification and improved outgroup attitudes was moderated by SDO (the indirect effect of cross-group friendship on outgroup attitudes via reduced ingroup only occurred for individuals scoring high, but not low, in SDO). Although there was a consistent moderating effect of SDO in high-status majority groups (Studies 1-5), but not low-status minority groups (Studies 3, 4, and 5), the interaction by SDO was not reliably stronger in high- than low-status groups. Findings are discussed in terms of better understanding deprovincialization effects of contact.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0146895PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4709236PMC
July 2016

The marbled crayfish as a paradigm for saltational speciation by autopolyploidy and parthenogenesis in animals.

Biol Open 2015 Oct 30;4(11):1583-94. Epub 2015 Oct 30.

Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany

The parthenogenetic all-female marbled crayfish is a novel research model and potent invader of freshwater ecosystems. It is a triploid descendant of the sexually reproducing slough crayfish, Procambarus fallax, but its taxonomic status has remained unsettled. By cross-breeding experiments and parentage analysis we show here that marbled crayfish and P. fallax are reproductively separated. Both crayfish copulate readily, suggesting that the reproductive barrier is set at the cytogenetic rather than the behavioural level. Analysis of complete mitochondrial genomes of marbled crayfish from laboratory lineages and wild populations demonstrates genetic identity and indicates a single origin. Flow cytometric comparison of DNA contents of haemocytes and analysis of nuclear microsatellite loci confirm triploidy and suggest autopolyploidisation as its cause. Global DNA methylation is significantly reduced in marbled crayfish implying the involvement of molecular epigenetic mechanisms in its origination. Morphologically, both crayfish are very similar but growth and fecundity are considerably larger in marbled crayfish, making it a different animal with superior fitness. These data and the high probability of a divergent future evolution of the marbled crayfish and P. fallax clusters suggest that marbled crayfish should be considered as an independent asexual species. Our findings also establish the P. fallax-marbled crayfish pair as a novel paradigm for rare chromosomal speciation by autopolyploidy and parthenogenesis in animals and for saltational evolution in general.
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http://dx.doi.org/10.1242/bio.014241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4728364PMC
October 2015

The reverse transcription signature of N-1-methyladenosine in RNA-Seq is sequence dependent.

Nucleic Acids Res 2015 Nov 13;43(20):9950-64. Epub 2015 Sep 13.

Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, Staudingerweg 5, 55128 Mainz, Germany

The combination of Reverse Transcription (RT) and high-throughput sequencing has emerged as a powerful combination to detect modified nucleotides in RNA via analysis of either abortive RT-products or of the incorporation of mismatched dNTPs into cDNA. Here we simultaneously analyze both parameters in detail with respect to the occurrence of N-1-methyladenosine (m(1)A) in the template RNA. This naturally occurring modification is associated with structural effects, but it is also known as a mediator of antibiotic resistance in ribosomal RNA. In structural probing experiments with dimethylsulfate, m(1)A is routinely detected by RT-arrest. A specifically developed RNA-Seq protocol was tailored to the simultaneous analysis of RT-arrest and misincorporation patterns. By application to a variety of native and synthetic RNA preparations, we found a characteristic signature of m(1)A, which, in addition to an arrest rate, features misincorporation as a significant component. Detailed analysis suggests that the signature depends on RNA structure and on the nature of the nucleotide 3' of m(1)A in the template RNA, meaning it is sequence dependent. The RT-signature of m(1)A was used for inspection and confirmation of suspected modification sites and resulted in the identification of hitherto unknown m(1)A residues in trypanosomal tRNA.
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http://dx.doi.org/10.1093/nar/gkv895DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4787781PMC
November 2015

Variable presence of 5-methylcytosine in commercial RNA and DNA.

RNA Biol 2015 14;12(10):1152-8. Epub 2015 Aug 14.

a Institute of Pharmacy and Biochemistry; Johannes Gutenberg-University of Mainz ; Mainz , Germany.

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http://dx.doi.org/10.1080/15476286.2015.1076612DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829282PMC
May 2016

Impact of RANK signalling on survival and chemotherapy response in osteosarcoma.

Pathology 2014 Aug;46(5):411-5

1Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria 2Department of Anatomy II, University Hospital Hamburg-Eppendorf, Hamburg, Germany 3Department of Orthopaedics, Medical University of Vienna, Vienna, Austria.

The receptor activator of NF-κB (RANK) signalling pathway represents a promising target for the therapy of bone-related tumours. In the present study we evaluated the impact of the expression of RANK and its ligand (RANKL) on survival and response to chemotherapy in osteosarcoma patients.Expression of RANK and RANKL was examined in 91 human osteosarcomas by immunohistochemistry using formalin fixed, paraffin embedded (FFPE) tumour samples. Results of the stainings were correlated with clinicopathological parameters and patient survival.Sixty-three osteosarcomas (69.2%) expressed RANK, whereas only eight cases (8.8%) showed expression of RANKL. Expression of RANK was significantly associated with shorter disease-free survival by Kaplan-Meier analysis (p=0.031). We further observed worse response to chemotherapy in RANK expressing tumours, which was statistically not significant (p=0.099). RANKL expression was significantly more frequent in osteosarcoma of the lower extremity than in any other location. Analysis of RANKL expression did not reveal any statistically significant correlation with disease-free or osteosarcoma-specific survival.In our study, we identified RANK expression as a negative prognostic factor regarding disease-free survival in osteosarcoma. Moreover, RANK might modulate response of human osteosarcoma to chemotherapy. Therefore, RANK signalling cascade is likely to provide a novel alternative to targeted therapy of osteosarcoma and deserves further investigation.
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http://dx.doi.org/10.1097/PAT.0000000000000116DOI Listing
August 2014

SIAH2 antagonizes TYK2-STAT3 signaling in lung carcinoma cells.

Oncotarget 2014 May;5(10):3184-96

Center for Molecular Biomedicine, University of Jena, Department of Biochemistry, Jena, Germany.

The Janus tyrosine kinases JAK1-3 and tyrosine kinase-2 (TYK2) are frequently hyperactivated in tumors. In lung cancers JAK1 and JAK2 induce oncogenic signaling through STAT3. A putative role of TYK2 in these tumors has not been reported. Here, we show a previously not recognized TYK2-STAT3 signaling node in lung cancer cells. We reveal that the E3 ubiquitin ligase seven-in-absentia-2 (SIAH2) accelerates the proteasomal degradation of TYK2. This mechanism consequently suppresses the activation of STAT3. In agreement with these data the analysis of primary non-small-cell lung cancer (NSCLC) samples from three patient cohorts revealed that compared to lung adenocarcinoma (ADC), lung squamous cell carcinoma (SCC) show significantly higher levels of SIAH2 and reduced STAT3 phosphorylation levels. Thus, SIAH2 is a novel molecular marker for SCC. We further demonstrate that an activation of the oncologically relevant transcription factor p53 in lung cancer cells induces SIAH2, depletes TYK2, and abrogates the tyrosine phosphorylation of STAT1 and STAT3. This mechanism appears to be different from the inhibition of phosphorylated JAKs through the suppressor of cytokine signaling (SOCS) proteins. Our study may help to identify molecular mechanisms affecting lung carcinogenesis and potential therapeutic targets.
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http://dx.doi.org/10.18632/oncotarget.1899DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4102802PMC
May 2014

The safety and clinical usefulness of dobutamine stress echocardiography among octogenarians.

Heart 2014 Jul 23;100(13):1001-7. Epub 2014 Apr 23.

Department of Cardiology, St George's Healthcare NHS Trust, London, UK.

Background: Increasing numbers of octogenarians are being referred for investigation of chest pain. While dobutamine stress echocardiography (DSE) has been shown to be useful in younger patients, its role among octogenarians remains unclear. This investigation aimed to investigate the safety and prognostic benefits of DSE on cardiac events and total mortality in octogenarians.

Methods: 550 consecutive patients aged ≥80 years underwent DSE for suspected cardiac chest pain. All subjects were followed-up prospectively until March 2011, and the study end-points were a major cardiac event and total mortality.

Results: One hundred and eighty-three (33%) patients had a positive DSE result, 271 (49%) had a normal study, and 164 (30%) had fixed-wall motion abnormalities. During a mean follow-up of 2.14±1.13 years, there were 217 (39%) cardiac events and 63 (11%) deaths, of which 46 (73%) were cardiac. The absolute risk of cardiac events increased with burden of ischaemia on DSE, from 13%/year (none), to 26%/year (1-3 ischaemic (LV) segments), and 38%/year (>3 ischaemic LV segments), p<0.001. Any ischaemia was associated with an additional 13 cardiac events per 100 person-years. In multivariate analysis, compared with non-ischaemic patients, the relative hazard of cardiac events for 1-3 and >3 ischaemic LV segments were 1.34 (95% CI 1.13 to 1.29) and 1.86 (95% CI 1.16 to 2.98), respectively. Addition of echocardiographic parameters to basic models improved the C statistic from 0.77 to 0.89 (p<0.001).

Conclusions: Among octogenarians referred with suspected cardiac chest pain, DSE is safe and, importantly, identifies a subset at high risk of cardiac events.
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http://dx.doi.org/10.1136/heartjnl-2013-305229DOI Listing
July 2014

Selectins mediate small cell lung cancer systemic metastasis.

PLoS One 2014 3;9(4):e92327. Epub 2014 Apr 3.

Department of Anatomy and Experimental Morphology, University Medical Center Hamburg- Eppendorf, Hamburg, Germany; Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg- Eppendorf, Hamburg, Germany.

Metastasis formation is the major reason for the extremely poor prognosis in small cell lung cancer (SCLC) patients. The molecular interaction partners regulating metastasis formation in SCLC are largely unidentified, however, from other tumor entities it is known that tumor cells use the adhesion molecules of the leukocyte adhesion cascade to attach to the endothelium at the site of the future metastasis. Using the human OH-1 SCLC line as a model, we found that these cells expressed E- and P-selectin binding sites, which could be in part attributed to the selectin binding carbohydrate motif sialyl Lewis A. In addition, protein backbones known to carry these glycotopes in other cell lines including PSGL-1, CD44 and CEA could be detected in in vitro and in vivo grown OH1 SCLC cells. By intravital microscopy of murine mesenterial vasculature we could capture SCLC cells while rolling along vessel walls demonstrating that SCLC cells mimic leukocyte rolling behavior in terms of selectin and selectin ligand interaction in vivo indicating that this mechanism might indeed be important for SCLC cells to seed distant metastases. Accordingly, formation of spontaneous distant metastases was reduced by 50% when OH-1 cells were xenografted into E-/P-selectin-deficient mice compared with wild type mice (p = 0.0181). However, as metastasis formation was not completely abrogated in selectin deficient mice, we concluded that this adhesion cascade is redundant and that other molecules of this cascade mediate metastasis formation as well. Using several of these adhesion molecules as interaction partners presumably make SCLC cells so highly metastatic.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0092327PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3974710PMC
January 2015

Why are all the white (Asian) kids sitting together in the cafeteria? Resegregation and the role of intergroup attributions and norms.

Br J Soc Psychol 2015 Mar 6;54(1):100-24. Epub 2014 Mar 6.

Yale-NUS College, Singapore.

Over three studies, we identified the phenomenon of ethnic 'resegregation' and assessed the extent to which it was predicted by attributions and norms, among other variables. Study 1, an observational study, showed extensive resegregation between White and Asian students in the cafeteria of a highly mixed school. In Study 2, we found evidence of attributional correspondence for White students, who attributed both their own and the outgroup's contact avoidance more to a lack of interest than fear of rejection, whereas Asian students attributed the outgroup's contact avoidance more to lack of interest, but preferred neither explanation of their own avoidance. In Study 3, we observed a pattern of attributional correspondence among both White and Asian students who attributed both their own and the outgroup's inaction in a hypothetical intergroup cafeteria scenario more to a lack of interest than fear of rejection. Study 3 also demonstrated longitudinally, for both groups, that own lack of interest in the outgroup reduced likelihood of cafeteria contact, whereas having outgroup friends and perceiving positive ingroup norms promoted it. In addition, positive outgroup norms promoted likelihood of cafeteria contact only for Asian students. We discuss how an understanding of the factors driving resegregation is critical to effectively realizing the potential of desegregated settings.
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http://dx.doi.org/10.1111/bjso.12064DOI Listing
March 2015

Contextual effect of positive intergroup contact on outgroup prejudice.

Proc Natl Acad Sci U S A 2014 Mar 3;111(11):3996-4000. Epub 2014 Mar 3.

Department of Psychology, Philipps-University Marburg, 35037 Marburg, Germany.

We assessed evidence for a contextual effect of positive intergroup contact, whereby the effect of intergroup contact between social contexts (the between-level effect) on outgroup prejudice is greater than the effect of individual-level contact within contexts (the within-level effect). Across seven large-scale surveys (five cross-sectional and two longitudinal), using multilevel analyses, we found a reliable contextual effect. This effect was found in multiple countries, operationalizing context at multiple levels (regions, districts, and neighborhoods), and with and without controlling for a range of demographic and context variables. In four studies (three cross-sectional and one longitudinal) we showed that the association between context-level contact and prejudice was largely mediated by more tolerant norms. In social contexts where positive contact with outgroups was more commonplace, norms supported such positive interactions between members of different groups. Thus, positive contact reduces prejudice on a macrolevel, whereby people are influenced by the behavior of others in their social context, not merely on a microscale, via individuals' direct experience of positive contact with outgroup members. These findings reinforce the view that contact has a significant role to play in prejudice reduction, and has great policy potential as a means to improve intergroup relations, because it can simultaneously impact large numbers of people.
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http://dx.doi.org/10.1073/pnas.1320901111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3964129PMC
March 2014

Neighborhood ethnic diversity and trust: the role of intergroup contact and perceived threat.

Psychol Sci 2014 Mar 16;25(3):665-74. Epub 2014 Jan 16.

1Department of Experimental Psychology, University of Oxford, and.

This research reported here speaks to a contentious debate concerning the potential negative consequences of diversity for trust. We tested the relationship between neighborhood diversity and out-group, in-group, and neighborhood trust, taking into consideration previously untested indirect effects via intergroup contact and perceived intergroup threat. A large-scale national survey in England sampled White British majority (N = 868) and ethnic minority (N = 798) respondents from neighborhoods of varying degrees of diversity. Multilevel path analyses showed some negative direct effects of diversity for the majority group but also confirmed predictions that diversity was associated indirectly with increased trust via positive contact and lower threat. These indirect effects had positive implications for total effects of diversity, cancelling out most negative direct effects. Our findings have relevance for a growing body of research seeking to disentangle effects of diversity on trust that has so far largely ignored the key role of intergroup contact.
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http://dx.doi.org/10.1177/0956797613508956DOI Listing
March 2014
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