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    Performance of water indices for large-scale water resources monitoring using Sentinel-2 data in Ethiopia
    (2024) Tesfaye, Mathias; Breuer, Lutz
    Evaluating the performance of water indices and water-related ecosystems is crucial for Ethiopia. This is due to limited information on the availability and distribution of water resources at the country scale, despite its critical role in sustainable water management, biodiversity conservation, and ecosystem resilience. The objective of this study is to evaluate the performance of seven water indices and select the best-performing indices for detecting surface water at country scale. Sentinel-2 data from December 1, 2021, to November 30, 2022, were used for the evaluation and processed using the Google Earth Engine. The indices were evaluated using qualitative visual inspection and quantitative accuracy indicators of overall accuracy, producer’s accuracy, and user’s accuracy. Results showed that the water index (WI) and automatic water extraction index with shadow (AWEIsh) were the most accurate ones to extract surface water. For the latter, WI and AWEIsh obtained an overall accuracy of 96% and 95%, respectively. Both indices had approximately the same spatial coverage of surface water with 82,650 km2 (WI) and 86,530 km2 (AWEIsh) for the whole of Ethiopia. The results provide a valuable insight into the extent of surface water bodies, which is essential for water resource planners and decision-makers. Such data can also play a role in monitoring the country’s reservoirs, which are important for the country’s energy and economic development. These results suggest that by applying the best-performing indices, better monitoring and management of water resources would be possible to achieve the Sustainable Development Goal 6 at the regional level.
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    Genome of Argania spinosa L.: insights into oil production and the tocopherol biosynthesis pathway
    (2024) Rupp, Oliver; Roessner, Clemens; Lederer-Ponzer, Naemi; Wollenweber, Tassilo Erik; Becker, Annette; Lamaoui, Mouna
    Argan (Argania spinosa L.) is a highly valued tree for its multiple uses as food and feed and for being linked to a broad range of benefits of pharmaceutical and cosmetic relevance. This multipurpose resource is becoming increasingly overused, which may disrupt the whole ecosystem’s sustainability. Due to the high socio-economic status of this tree, research interventions are needed to reverse the forest regressive trend, restore the disturbed ecosystem, and conserve genetic diversity. However, research on argan is restricted by the lack of accessible information on the genetic and genomic bases of the species, specifically a functional annotated genome. Herein, we report the reference transcriptome aided annotation of the argan tree genome using de novo gene prediction programs aided by homology information from different plants. The results of the genome annotation using AUGUSTUS were subsequently improved by performing RNA sequencing. A total of 62,590 gene loci could be identified with 82,286 isoforms and a BUSCO completeness of 91.7%. To gain insight into the agronomically important compounds in argan oil, a comparative genome analysis and ortholog identification was performed, followed by phylogenetic tree construction of the main biosynthesis genes. Among those are fatty acids and tocopherols, the latter being the main factor behind the increasing demands for argan oil. Our analysis is the initial step to provide breeders, geneticists, and the industries with adequate genomic information, facilitate improvement of economically important traits and to selectively adapt the tree to the increasing impact of climate change.
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    Beyond Language Barriers: Allowing Multiple Languages in Postsecondary Chemistry Classes Through Multilingual Machine Learning
    (2024) Martin, Paul P.; Graulich, Nicole
    Students who learn the language of instruction as an additional language represent a heterogeneous group with varying linguistic and cultural backgrounds, contributing to classroom diversity. Because of the manifold challenges these students encounter while learning the language of instruction, additional barriers arise for them when engaging in chemistry classes. Adapting teaching practices to the language skills of these students, for instance, in formative assessments, is essential to promote equity and inclusivity in chemistry learning. For this reason, novel educational practices are needed to meet each student’s unique set of language capabilities, irrespective of course size. In this study, we propose and validate several approaches to allow undergraduate chemistry students who are not yet fluent in the language of instruction to complete a formative assessment in their preferred language. A technically easy-to-implement option for instructors is to use translation tools to translate students’ reasoning in any language into the instructor’s language. Besides, instructors could also establish multilingual machine learning models capable of automatically analyzing students’ reasoning regardless of the applied language. Herein, we evaluated both opportunities by comparing the reliability of three translation tools and determining the degree to which multilingual machine learning models can simultaneously assess written arguments in different languages. The findings illustrate opportunities to apply machine learning for analyzing students’ reasoning in multiple languages, demonstrating the potential of such techniques in ensuring equal access for learners of the language of instruction.
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    Variations in Access to Social Support: the Effects of Residential Mobility and Spatial Proximity to Kin and Family
    (2024) Hagge, Kyra; Schacht, Diana
    Increasing residential mobility is said to challenge existing social support systems as mobility raises geographic distances between family members. Since family social support is essential for health and well-being, this study investigates whether residential mobility affects familial social support following changes in proximity to family and kin. By applying a stepwise linear regression on data from the German Socio-Economic Panel study, this paper is looking at variations between different residential mobility trajectories regarding social support provision and spatial proximity to family members in Germany over a 10-year period. Our findings show that people who are moving within Germany are receiving significantly more social support from their family and kin, while internationally mobile respondents receive less compared to non-mobile people. Mediation analyses show that proximity to family and kin are accounting for the negative effect of international mobility on social support but cannot explain the positive effect of internal migration.
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    Analysis of organochlorines and polycyclic aromatic hydrocarbons designed for pollutant biomonitoring in three seabird matrices
    (2024) Michel, Lucie; Oró-Nolla, Bernat; Dell’Omo, Giacomo; Quillfeldt, Petra; Lacorte, Sílvia
    Pollutant biomonitoring demands analytical methods to cover a wide range of target compounds, work with minimal sample amounts, and apply least invasive and reproducible sampling procedures. We developed a method to analyse 68 bioaccumulative organic pollutants in three seabird matrices: plasma, liver, and stomach oil, representing different exposure phases. Extraction efficiency was assessed based on recoveries of spiked surrogate samples, then the method was applied to environmental samples collected from Scopoli’s shearwater (Calonectris diomedea). Extraction was performed in an ultrasonic bath, purification with Florisil cartridges (5 g, 20 mL), and analysis by GC–Orbitrap–MS. Quality controls at 5 ng yielded satisfactory recoveries (80–120%) although signal intensification was found for some compounds. The method permitted the detection of 28 targeted pollutants in the environmental samples. The mean sum of organic pollutants was 4.25 ± 4.83 ng/g in plasma, 1634 ± 2990 ng/g in liver, and 233 ± 111 ng/g in stomach oil (all wet weight). Pollutant profiles varied among the matrices, although 4,4′-DDE was the dominant compound overall. This method is useful for pollutant biomonitoring in seabirds and discusses the interest of analysing different matrices.
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    Reconsidering the Relationship Between Anti-immigration Attitudes and Preferences for the AfD Using Implicit Attitudes Measures
    (2024) Kleinert, Manuel
    The study of demand-side factors for the success of radical right-wing populist parties has highlighted anti-immigration attitudes (AIA) as a particularly important predictor. However, these findings have relied heavily on direct self-report measures. This preregistered study theorises that direct measures may have underestimated, through social desirability bias, or overestimated, through cognitive dissonance avoidance, the relationship between AIA and support for the German radical right-wing party Alternative for Germany (AfD). A direct questionnaire and two Single-Category Implicit Association Tests were administered to a stratified sample of the German population (N = 369) to measure both explicit and implicit preferences for the AfD and AIA. Results reveal that the firm relationship between AIA and AfD voting intentions is strongest in an all-explicit setting, reduced in mixed analyses, and eliminated in the all-implicit model. This provides evidence that the need for respondents to report consistent ideologies may be a more serious threat to valid results in political attitudes research than is generally assumed. Social desirability seems to be less of an issue when assessing the strength of the correlation between right-wing attitudes and AfD preferences. Thorough robustness checks confirmed the reliability of these findings.
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    On the relationship between various anticoagulants and robot-assisted radical prostatectomy: a single-surgeon serial analysis
    (2024) Farzat, Mahmoud; Wagenlehner, Florian M.
    Prostate cancer patients often have other health conditions and take anticoagulants. It was believed that surgery under anticoagulants could worsen surgical results. This study aims to explore the safety of robot-assisted prostatectomy in anticoagulated patients, without any exclusion criteria. The study included 500 patients who underwent RARP by a single surgeon between April 2019 and August 2022. Patients were divided into two groups: Group 1, consisting of 376 men (75.2%), did not receive any anticoagulation, while Group 2, with 124 patients (24.8%), received different forms of anticoagulation. Then, the anticoagulation group was divided into 4 subgroups according to their definite anticoagulation: the aspirin 15.6%, new oral anticoagulants (NOAC) 5.4%, Vitamin K antagonist (VKA) 2%, and dual-antiplatelet therapy (DAPT) 1.8% subgroup. Postoperative complications and readmission rates were compared between the two study groups and subgroups. Patients in the combined group 2 were older and they also carried more comorbidities compared to men in group 1 (p = 0.03, p = 0.001).The study groups had similar oncological results, with 40.4% of patients having locally advanced cancers. Catheter days were longer in the anticoagulation group (4.5 vs 4 days, p = 0.001). No significant differences were observed between study groups for overall, minor, and major complications (p = 0.160, 0.100, and 0.915, respectively). In addition, readmissions were low (5.6%) and similar between the study groups (p = 0.635). Under cautious management, RARP under diverse anticoagulation regimes is safe and has comparable results to men with no medications. Further prospective studies must be conducted to confirm our findings.
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    Consumer responses to human-AI collaboration at organizational frontlines: strategies to escape algorithm aversion in content creation
    (2024) Haupt, Martin; Freidank, Jan; Haas, Alexander
    Although Artificial Intelligence can offer significant business benefits, many consumers have negative perceptions of AI, leading to negative reactions when companies act ethically and disclose its use. Based on the pervasive example of content creation (e.g., via tools like ChatGPT), this research examines the potential for human-AI collaboration to preserve consumers' message credibility judgments and attitudes towards the company. The study compares two distinct forms of human-AI collaboration, namely AI-supported human authorship and human-controlled AI authorship, with traditional human authorship or full automation. Building on the compensatory control theory and the algorithm aversion concept, the study evaluates whether disclosing a high human input share (without explicit control) or human control over AI (with lower human input share) can mitigate negative consumer reactions. Moreover, this paper investigates the moderating role of consumers’ perceived morality of companies’ AI use. Results from two experiments in different contexts reveal that human-AI collaboration can alleviate negative consumer responses, but only when the collaboration indicates human control over AI. Furthermore, the effects of content authorship depend on consumers' moral acceptance of a company's AI use. AI authorship forms without human control lead to more negative consumer responses in case of low perceived morality (and no effects in case of high morality), whereas messages from AI with human control were not perceived differently to human authorship, irrespective of the morality level. These findings provide guidance for managers on how to effectively integrate human-AI collaboration into consumer-facing applications and advises to take consumers' ethical concerns into account.
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    Insights of Inflammatory Heart Involvement in Cardiac Sarcoidosis – A Systemic Review
    (2024) Treiber, Julia; Hamm, Christian W.; Sossalla, Samuel T.; Rolf, Andreas
    Purpose of the Review: The purpose of this paper is to review the current knowledge regarding imaging inflammation in cardiac sarcoidosis (CS). Recent Findings: Noninvasive imaging methods like cardiac magnetic resonance (CMR) and 18-fluorodeoxyglucose (18FDG) positron-emission tomography-computed tomography (PET-CT) scans have emerged as the most important modalities in diagnosing and monitor therapy efficacy in CS. The differentiation between an active and a chronic, silent clinical state is crucial for decision making. T1- and T2-mapping by CMR provide a unique opportunity to discriminate normal and diseased myocardium by detecting myocardial edema and fibrosis. While T1-mapping is sensitive to fibrosis and edema, T2 is primarily influenced by tissue water content. Increased 18-fluorodeoxyglucose (18FDG) uptake in positron-emission tomography-computed tomography (PET-CT) scan is a hallmark feature of CS and defines active inflammation. Therefore, the hybrid application of both CMR and 18FDG-PET-CT scans has evolved as the standard procedure to detect CS and monitor the therapeutic response. Summary: Imaging inflammation in CS is basically performed by CMR T2-mapping and 18FDG uptake in PET-CT scan. Both are reliable methods in identifying active CS and follow up therapy and can be used synergistically. Additionally CMR provides further prognostic insights by late gadolinium enhancement that increases the risk for malignant arrhythmia and for relapse after therapy weaning.
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    Clinical effectiveness of pit and fissure sealants in primary and permanent teeth of children and adolescents: an umbrella review
    (2024) Amend, S.; Boutsiouki, C.; Winter, J.; Kloukos, D.; Frankenberger, R.; Krämer, N.
    Purpose: This umbrella review aimed to critically appraise the evidence published in systematic reviews (SRs) on the clinical effectiveness of sealants compared with each other/the non-use in primary/permanent teeth of children and adolescents with at least 12-month follow-up. Methods: A systematic literature search on 4 electronic databases was conducted up to January 18th, 2023. Following handsearching, two review authors independently screened retrieved articles, extracted data, and assessed the risk of bias (RoB) using the risk of bias in systematic reviews (ROBIS) tool. Based on a citation matrix, the overlap was interpreted by the corrected covered area (CCA). Results: Of 239 retrieved records, 7 SRs met the eligibility criteria with a moderate overlap among them (CCA = 7.4%). For primary molars, in 1120 1.5- to 8-year-old children, data on the clinical effectiveness of sealants were inconclusive. For permanent molars, 3 SRs found a significant caries risk reduction for sealants versus non-use (≤ 36-month follow-up). There was insufficient evidence to proof superiority of sealants over fluoride varnish for caries prevention (3 SRs), and to rank sealant materials according to the best clinical effectiveness in permanent molars. One study was rated at low and 6 at high RoB, which did not allow for a valid quantitative synthesis. Conclusion: Considering the limitations of this umbrella review, sealants are more effective for caries prevention in children’s permanent molars compared to no treatment. Future well-implemented RCTs are needed to draw reliable conclusions on the clinical effectiveness of sealants in primary and permanent teeth of children and adolescents.
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    Cognitive profile of kidney transplant patients and impact of deceased vs. living donor transplantation
    (2024) Doerr, Johanna Marie; Juenemann, Martin; Becker, Anna; Nahrgang, Christian; Rainer, Lucy; Liese, Juliane; Hecker, Andreas; Wolter, Martin; Weimer, Rolf; Karakizlis, Hristos
    Background: It is important to learn more about the prevalence, severity and characteristics (i.e., which cognitive abilities are especially affected) of cognitive impairment in kidney transplant patients. Furthermore, the impact of living vs. deceased donor renal transplantation on cognitive outcome in this patient group needs further studies. Methods: Fifty-nine patients (43 men, age 55 ± 13 years) who received a deceased donor or living donor kidney transplant, completed a comprehensive neuropsychological test assessment. Neuropsychological tests explored the cognitive domains of verbal and visual memory, attention, and executive functions. Results: Fifteen percent of the patients had mild, 25% moderate, and 15% severe cognitive impairment. The level of domain-specific cognitive deficit differed between verbal memory, attention, and executive functions (χ2(2) = 7.11, p = 0.029). On average, patients showed the highest deficit in executive functions, and the lowest deficit in verbal memory. Patients who received a kidney graft from a deceased donor were more likely to have a cognitive impairment than those who received a kidney graft from a living donor (OR = 3.03, 95% CI [0.99,9.32], Wald χ2(1) = 3.74, p = 0.053). This effect was independent of time on dialysis as well as of creatinine levels, or creatinine clearance. Conclusions: Our results show that in kidney transplant patients with cognitive impairment, the cognitive domain of executive functions is the most affected one. This might be detrimental for quality of life. The fact that patients who received living donor kidneys seem to do better in terms of cognition than patients with deceased donor kidneys deserves more attention in future research.
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    Can biocontrol be the game-changer in integrated pest management? A review of definitions, methods and strategies
    (2024) Galli, Matteo; Feldmann, Falko; Vogler, Ute Katharina; Kogel, Karl-Heinz
    Global agriculture is heavily dependent on sustainable plant protection. Worldwide, the concept of integrated pest management (IPM) is being followed. IPM utilizes a range of strategies, with chemical synthetic pesticides being employed only as a last resort. However, in agricultural practice, farmers continue to rely primarily on this option. To further reduce this dependence, new strategies are being sought to strengthen the use of biological control within the IPM approach including the identification of novel non-synthetic natural compounds. Here, we discuss and report on the state of the art in biological control research in areas such as biocontrol agents and application of ecological principles. These practices can help to establish sustainable plant protection systems, with the greatest impact achieved when they are used in appropriate combinations. We highlight the conditions that currently prevent or hinder the increased use of biocontrol measures. On the background of agroecological experiences, we discuss why additional advancements in plant protection practices are imperative to more effectively break the life cycles of pests, diseases and weeds. We emphasize the significance of a judicious application of chemical control technologies, adapted to local conditions. Additionally, we highlight the key role and expertise of operators in implementing these practices and their knowledge thereof.
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    The nematode signaling molecule ascr#18 induces prepenetration defenses in wheat against a leaf rust fungus
    (2024) Kamboj, Akshita; Thielmann, Jennifer; Delfan, Saba; Kloppe, Tim; Schulz, Philipp; Manohar, Murli; Schroeder, Frank C.; Klessig, Daniel F.; Kogel, Karl-Heinz
    Leaf rust, caused by the pathogenic biotrophic rust fungus Puccinia triticina (Pt), is one of the most destructive wheat diseases worldwide; its negative impact on crop yields is exacerbated by increasing temperatures due to climate change. Ascarosides are nematode pheromones that induce resistance to microbial pathogens and pests in a wide range of crops, making them valuable components in biocontrol scenarios. We investigated the effect on infection of various wheat (Triticum aestivum) genotypes with the virulent Pt race 77W × R by ascr#18, the major ascaroside secreted into the rhizosphere by plant-parasitic nematodes. Spraying the leaves with ascr#18 24 h before inoculation with fungal uredospores slowed disease development and resulted in a reduction of the number of rust pustules on treated compared to untreated leaves. Dose–response analysis over the nano- and micromolar range revealed a broad optimum concentration down to 0.01nM ascr#18. Microscopic analysis showed very early arrest of the fungus at the appressorial stage, with associated enhanced local accumulation of H2O2 and abortive stoma penetration. Similarly, ascr#18 also induced strong resistance to Pt race PKTTS, confirming its race-unspecific biocontrol activity. The results of this study are consistent with and extend previous research that has shown that ascr#18 activates plant immunity and thus protects plants from pathogens even at very low doses.
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    T cells in testicular germ cell tumors: new evidence of fundamental contributions by rare subsets
    (2024) Islam, Rashidul; Heyer, Jannis; Figura, Miriam; Wang, Xiaoyan; Nie, Xichen; Nathaniel, Benedict; Indumathy, Sivanjah; Hartmann, Katja; Pleuger, Christiane; Fijak, Monika; Kliesch, Sabine; Dittmar, Florian; Pilatz, Adrian; Wagenlehner, Florian; Hedger, Mark; Loveland, Bruce; Hotaling, James H.; Guo, Jingtao; Loveland, Kate L.; Schuppe, Hans-Christian; Fietz, Daniela
    Background: Immune cell infiltration is heterogeneous but common in testicular germ cell tumors (TGCT) and pre-invasive germ cell neoplasia in situ (GCNIS). Tumor-infiltrating T cells including regulatory T (Treg) and follicular helper T (Tfh) cells are found in other cancer entities, but their contributions to TGCT are unknown. Methods: Human testis specimens from independent patient cohorts were analyzed using immunohistochemistry, flow cytometry and single-cell RNA sequencing (scRNA-seq) with special emphasis on delineating T cell subtypes. Results: Profound changes in immune cell composition within TGCT, shifting from macrophages in normal testes to T cells plus B and dendritic cells in TGCT, were documented. In most samples (96%), the CD4+ T cell frequency exceeded that of CD8+ cells, with decreasing numbers from central to peripheral tumor areas, and to tumor-free, contralateral testes. T cells including Treg and Tfh were most abundant in seminoma compared to mixed tumors and embryonal carcinoma. Conclusion: Despite considerable heterogeneity between patients, T cell subtypes form a key part of the TGCT microenvironment. The novel finding of rare Treg and Tfh cells in human testis suggests their involvement in TGCT pathobiology, with implications for understanding tumor progression, to assess patients’ prognosis, and as putative targets for personalized immunotherapy.
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    Chemo-mechanical failure mechanisms of the silicon anode in solid-state batteries
    (2024) Huo, Hanyu; Jiang, Ming; Bai, Yang; Ahmed, Shamail; Volz, Kerstin; Hartmann, Hannah; Henss, Anja; Singh, Chandra Veer; Raabe, Dierk; Janek, Jürgen
    Silicon is a promising anode material due to its high theoretical specific capacity, low lithiation potential and low lithium dendrite risk. Yet, the electrochemical performance of silicon anodes in solid-state batteries is still poor (for example, low actual specific capacity and fast capacity decay), hindering practical applications. Here the chemo-mechanical failure mechanisms of composite Si/Li6PS5Cl and solid-electrolyte-free silicon anodes are revealed by combining structural and chemical characterizations with theoretical simulations. The growth of the solid electrolyte interphase at the Si|Li6PS5Cl interface causes severe resistance increase in composite anodes, explaining their fast capacity decay. Solid-electrolyte-free silicon anodes show sufficient ionic and electronic conductivities, enabling a high specific capacity. However, microscale void formation during delithiation causes larger mechanical stress at the two-dimensional interfaces of these anodes than in composite anodes. Understanding these chemo-mechanical failure mechanisms of different anode architectures and the role of interphase formation helps to provide guidelines for the design of improved electrode materials.
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    An ecotoxicological view on malaria vector control with ivermectin-treated cattle
    (2024) Heinrich, Andre Patrick; Pooda, Sié Hermann; Porciani, Angélique; Zéla, Lamidi; Schinzel, Alexandra; Moiroux, Nicolas; Roberge, Christophe; Martina, Marie-Sophie; Courjaud, Anne-Laure; Dabiré, Roch K.; Römbke, Jörg; Düring, Rolf-Alexander; Mouline, Karine
    Malaria remains an enduring challenge in sub-Saharan Africa, affecting public health and development. Control measures can include the use of insecticides that target adult Anopheles mosquitoes transmitting the malaria-causing Plasmodium parasite. Such mosquitoes can also bite livestock, allowing vector populations to be maintained at levels that enable parasite transmission. Thus, one way to control the spread of malaria includes the use of endectocide-treated livestock which renders the blood of cattle toxic to such mosquito populations. Here we present an ecotoxicological perspective on malaria vector control, using cattle treated with the endectocide ivermectin to target zoophagic and opportunistic Anopheles coluzzii mosquitoes. Our study employs an innovative, long-acting injectable ivermectin formulation with over 6 months of sustained mosquitocidal activity. Robust vector population modelling underscores its promising field effectiveness. Environmental implications (soil sorption and dissipation) of excreted ivermectin and potential ecotoxicological risks to non-target dung organisms in West Africa are discussed, in addition to actionable, locally inspired risk mitigation measures to protect sub-Saharan soils and agroecosystems from chemical pollution. We highlight how ecotoxicology and environmental chemistry improve livestock-based vector control with ivermectin for effective and more sustainable malaria management.
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    A common gene signature of the right ventricle in failing rat and human hearts
    (2024) Jurida, Liane; Werner, Sebastian; Knapp, Fabienne; Niemann, Bernd; Li, Ling; Grün, Dimitri; Wirth, Stefanie; Weber, Axel; Beuerlein, Knut; Liebetrau, Christoph; Wiedenroth, Christoph B.; Guth, Stefan; Kojonazarov, Baktybek; Jafari, Leili; Weissmann, Norbert; Günther, Stefan; Braun, Thomas; Bartkuhn, Marek; Schermuly, Ralph T.; Dorfmüller, Peter; Yin, Xiaoke; Mayr, Manuel; Schmitz, M. Lienhard; Czech, Laureen; Schlüter, Klaus-Dieter; Schulz, Rainer; Rohrbach, Susanne; Kracht, Michael
    The molecular mechanisms of progressive right heart failure are incompletely understood. In this study, we systematically examined transcriptomic changes occurring over months in isolated cardiomyocytes or whole heart tissues from failing right and left ventricles in rat models of pulmonary artery banding (PAB) or aortic banding (AOB). Detailed bioinformatics analyses resulted in the identification of gene signature, protein and transcription factor networks specific to ventricles and compensated or decompensated disease states. Proteomic and RNA-FISH analyses confirmed PAB-mediated regulation of key genes and revealed spatially heterogeneous mRNA expression in the heart. Intersection of rat PAB-specific gene sets with transcriptome datasets from human patients with chronic thromboembolic pulmonary hypertension (CTEPH) led to the identification of more than 50 genes whose expression levels correlated with the severity of right heart disease, including multiple matrix-regulating and secreted factors. These data define a conserved, differentially regulated genetic network associated with right heart failure in rats and humans.
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    Expression, purification and crystallization of the photosensory module of phytochrome B (phyB) from Sorghum bicolor
    (2024) Shenkutie, Sintayehu Manaye; Nagano, Soshichiro; Hughes, Jon
    Sorghum, a short-day tropical plant, has been adapted for temperate grain production, in particular through the selection of variants at the MATURITY loci (Ma1–Ma6) that reduce photoperiod sensitivity. Ma3 encodes phytochrome B (phyB), a red/far-red photochromic biliprotein photoreceptor. The multi-domain gene product, comprising 1178 amino acids, autocatalytically binds the phytochromobilin chromophore to form the photoactive holophytochrome (Sb.phyB). This study describes the development of an efficient heterologous overproduction system which allows the production of large quantities of various holoprotein constructs, along with purification and crystallization procedures. Crystals of the Pr (red-light-absorbing) forms of NPGP, PGP and PG (residues 1–655, 114–655 and 114–458, respectively), each C-terminally tagged with His6, were successfully produced. While NPGP crystals did not diffract, those of PGP and PG diffracted to 6 and 2.1 Å resolution, respectively. Moving the tag to the N-terminus and replacing phytochromobilin with phycocyanobilin as the ligand produced PG crystals that diffracted to 1.8 Å resolution. These results demonstrate that the diffraction quality of challenging protein crystals can be improved by removing flexible regions, shifting fusion tags and altering small-molecule ligands.