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Time evolution of the local density of states of strongly correlated fermions coupled to a nanoprobe
No full textDeutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Philipps-Universität Marburg http://dx.doi.org/10.13039/10000896
Tree Diversity Increases Carbon Stocks and Fluxes Above—But Not Belowground in a Tropical Forest Experiment
No full textABSTRACT International commitments advocate large‐scale forest restoration as a nature‐based solution to climate change mitigation through carbon (C) sequestration. Mounting evidence suggests that mixed compared to monospecific planted forests may sequester more C, exhibit lower susceptibility to climate extremes and offer a broader range of ecosystem services. However, experimental studies comprehensively examining the control of tree diversity on multiple C stocks and fluxes above‐ and belowground are lacking. To address this gap, we leverage data from the Sardinilla experiment in Panama, the oldest tropical tree diversity experiment, which features a gradient of one‐, two‐, three‐ and five‐species mixtures of native tree species. Over 16 years, we measured multiple above‐ and belowground C stocks and fluxes, ranging from tree aboveground C, over leaf litter C production, to soil organic carbon (SOC). We show that tree diversity significantly increased aboveground C stocks and fluxes, with a 57% higher gain in aboveground tree C in five‐species mixtures compared to monocultures (35.7 ± 1.8 vs. 22.8 ± 3.4 Mg C ha −1 ) 16 years after planting. In contrast, we observed a net reduction in SOC (on average −11.2 ± 1.1 Mg C ha −1 across diversity levels) and no significant difference in SOC 3 stocks (the predominantly tree‐derived, i.e., C 3 plant‐derived SOC fraction) between five‐species mixtures and monocultures (13.0 ± 0.9 vs. 15.1 ± 1.3 Mg C ha −1 ). Positive tree diversity effects persisted despite repeated climate extremes and strengthened over time for aboveground tree growth. Structural equation models showed that higher tree growth in mixtures enhanced leaf litter and coarse woody debris C fluxes to the soil, resulting in a tightly linked C cycle aboveground. However, we did not observe significant links between above‐ and belowground C stocks and fluxes. Our study elucidates the mechanisms through which higher tree diversity bolsters the climate mitigation potential of tropical forest restoration. Restoration schemes should prioritize mixed over monospecific planted forests.RESUMEN Los compromisos internacionales abogan por la restauración forestal a gran escala como solución basada en la naturaleza para mitigar el cambio climático mediante el secuestro de carbono (C). Cada vez hay más pruebas de que los bosques mixtos, en comparación con los monoespecíficos, pueden secuestrar más C, ser menos susceptibles a los extremos climáticos y ofrecer una gama más amplia de servicios ecosistémicos. Sin embargo, faltan estudios experimentales que examinen exhaustivamente cómo la diversidad de árboles controla los diferentes reservas y flujos de C por encima y por debajo del suelo. Para abordar esta carencia, analizamos los datos del experimento Sardinilla en Panamá, el experimento de diversidad arbórea tropical más antiguo, que tiene un gradiente de mezclas de una, dos, tres y cinco especies de árboles autóctonos. A lo largo de 16 años, hemos medido diferentes reservas y flujos de C por encima y por debajo del suelo, incluyendo entre otros biomasa viva aérea de los árboles, hojarasca, y materia orgánica del suelo (SOC). Nuestro estudio demuestra que la diversidad arbórea incrementó significativamente las reservas y flujos de C encima del suelo, con una ganancia de C en biomasa viva aérea de los árboles un 57% mayor en masas mixtas de cinco especies en comparación con monocultivos (35,7 ± 1,8 vs. 22,8 ± 3,4 Mg C ha −1 ) después de 16 años desde la plantación. Por el contrario, observamos una reducción neta del SOC (en promedio −11,2 ± 1,1 Mg C ha −1 a través de niveles de diversidad) y ninguna diferencia significativa en las existencias de SOC 3 (la fracción de SOC predominantemente derivada de los árboles, es decir, derivada de plantas C 3 ) entre las masas mixtas de cinco especies y los monocultivos (13,0 ± 0,9 vs. 15,1 ± 1,3 Mg C ha −1 ). Los efectos positivos de la diversidad arbórea persistieron a pesar de repetidos extremos climáticos y se reforzaron con el tiempo para el crecimiento arbóreo por encima del suelo. Modelos de ecuaciones estructurales mostraron que un mayor crecimiento arbóreo en las masas mixtas mejoraba los flujos de C de la hojarasca y de la madera muerta hacia el suelo, dando lugar a un ciclo de C por encima del suelo estrechamente vinculado. Sin embargo, no se observaron vínculos significativos entre las reservas y flujos de C por encima y por debajo del suelo. Nuestro estudio mejora la comprensión de los mecanismos a través de los cuales una mayor diversidad arbórea refuerza el potencial de mitigación climática de la restauración de los bosques tropicales. Los proyectos de restauración deberían dar prioridad a los bosques mixtos frente a los monoespecíficos.ABSTRACT International commitments advocate large‐scale forest restoration as a nature‐based solution to climate change mitigation through carbon (C) sequestration. Mounting evidence suggests that mixed compared to monospecific planted forests may sequester more C, exhibit lower susceptibility to climate extremes and offer a broader range of ecosystem services. However, experimental studies comprehensively examining the control of tree diversity on multiple C stocks and fluxes above‐ and belowground are lacking. To address this gap, we leverage data from the Sardinilla experiment in Panama, the oldest tropical tree diversity experiment, which features a gradient of one‐, two‐, three‐ and five‐species mixtures of native tree species. Over 16 years, we measured multiple above‐ and belowground C stocks and fluxes, ranging from tree aboveground C, over leaf litter C production, to soil organic carbon (SOC). We show that tree diversity significantly increased aboveground C stocks and fluxes, with a 57% higher gain in aboveground tree C in five‐species mixtures compared to monocultures (35.7 ± 1.8 vs. 22.8 ± 3.4 Mg C ha −1 ) 16 years after planting. In contrast, we observed a net reduction in SOC (on average −11.2 ± 1.1 Mg C ha −1 across diversity levels) and no significant difference in SOC 3 stocks (the predominantly tree‐derived, i.e., C 3 plant‐derived SOC fraction) between five‐species mixtures and monocultures (13.0 ± 0.9 vs. 15.1 ± 1.3 Mg C ha −1 ). Positive tree diversity effects persisted despite repeated climate extremes and strengthened over time for aboveground tree growth. Structural equation models showed that higher tree growth in mixtures enhanced leaf litter and coarse woody debris C fluxes to the soil, resulting in a tightly linked C cycle aboveground. However, we did not observe significant links between above‐ and belowground C stocks and fluxes. Our study elucidates the mechanisms through which higher tree diversity bolsters the climate mitigation potential of tropical forest restoration. Restoration schemes should prioritize mixed over monospecific planted forests.RESUMEN Los compromisos internacionales abogan por la restauración forestal a gran escala como solución basada en la naturaleza para mitigar el cambio climático mediante el secuestro de carbono (C). Cada vez hay más pruebas de que los bosques mixtos, en comparación con los monoespecíficos, pueden secuestrar más C, ser menos susceptibles a los extremos climáticos y ofrecer una gama más amplia de servicios ecosistémicos. Sin embargo, faltan estudios experimentales que examinen exhaustivamente cómo la diversidad de árboles controla los diferentes reservas y flujos de C por encima y por debajo del suelo. Para abordar esta carencia, analizamos los datos del experimento Sardinilla en Panamá, el experimento de diversidad arbórea tropical más antiguo, que tiene un gradiente de mezclas de una, dos, tres y cinco especies de árboles autóctonos. A lo largo de 16 años, hemos medido diferentes reservas y flujos de C por encima y por debajo del suelo, incluyendo entre otros biomasa viva aérea de los árboles, hojarasca, y materia orgánica del suelo (SOC). Nuestro estudio demuestra que la diversidad arbórea incrementó significativamente las reservas y flujos de C encima del suelo, con una ganancia de C en biomasa viva aérea de los árboles un 57% mayor en masas mixtas de cinco especies en comparación con monocultivos (35,7 ± 1,8 vs. 22,8 ± 3,4 Mg C ha −1 ) después de 16 años desde la plantación. Por el contrario, observamos una reducción neta del SOC (en promedio −11,2 ± 1,1 Mg C ha −1 a través de niveles de diversidad) y ninguna diferencia significativa en las existencias de SOC 3 (la fracción de SOC predominantemente derivada de los árboles, es decir, derivada de plantas C 3 ) entre las masas mixtas de cinco especies y los monocultivos (13,0 ± 0,9 vs. 15,1 ± 1,3 Mg C ha −1 ). Los efectos positivos de la diversidad arbórea persistieron a pesar de repetidos extremos climáticos y se reforzaron con el tiempo para el crecimiento arbóreo por encima del suelo. Modelos de ecuaciones estructurales mostraron que un mayor crecimiento arbóreo en las masas mixtas mejoraba los flujos de C de la hojarasca y de la madera muerta hacia el suelo, dando lugar a un ciclo de C por encima del suelo estrechamente vinculado. Sin embargo, no se observaron vínculos significativos entre las reservas y flujos de C por encima y por debajo del suelo. Nuestro estudio mejora la comprensión de los mecanismos a través de los cuales una mayor diversidad arbórea refuerza el potencial de mitigación climática de la restauración de los bosques tropicales. Los proyectos de restauración deberían dar prioridad a los bosques mixtos frente a los monoespecíficos.Natural Sciences and Engineering Research Council of Canada https://doi.org/10.13039/501100000038Smithsonian Tropical Research Institute https://doi.org/10.13039/100009201Deutsche Forschungsgemeinschaft https://doi.org/10.13039/50110000165
Exosomal mir-126-3p derived from endothelial cells induces ion channel dysfunction by targeting RGS3 signaling in cardiomyocytes: a novel mechanism in Takotsubo cardiomyopathy
No full textAbstract Background Takotsubo cardiomyopathy (TTC) is marked by an acute, transient, and reversible left ventricular systolic dysfunction triggered by stress, with endothelial dysfunction being one of its pathophysiological mechanisms. However, the precise molecular mechanism underlying the interaction between endothelial cells and cardiomyocytes during TTC remains unclear. This study reveals that exosomal miRNAs derived from endothelial cells exposed to catecholamine contribute to ion channel dysfunction in the setting of TTC. Methods Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were treated with epinephrine (Epi) or exosomes (Exo) from Epi-treated human cardiac microvascular endothelial cells (HCMECs) or Exo derived from HCMECs transfected with miR-126-3p. The immunofluorescence staining, flow cytometry, qPCR, single-cell contraction, intracellular calcium transients, patch-clamp, dual luciferase reporter assay and western blot were performed for the study. Results Modeling TTC with high doses of epinephrine (Epi) treatment in hiPSC-CMs shows suppression of depolarization velocity (Vmax), prolongation of action potential duration (APD), and induction of arrhythmic events. Exo derived from HCMECs treated with Epi (Epi-exo) mimicked or enhanced the effects of Epi. Epi exposure led to elevated levels of miR-126-3p in both HCMECs and their exosomes. Exo enriched with miR-126-3p demonstrated similar effects as Epi-exo, establishing the crucial role of miR-126-3p in the mechanism of Epi-exo. Dual luciferase reporter assay coupled with gene mutation techniques identified that miR-126-3p was found to target the regulator of G-protein signaling 3 (RGS3) gene. Western blot and qPCR analyses confirmed that miR-126-3p-mimic reduced RGS3 expression in both HCMECs and hiPSC-CMs, indicating miR-126-3p inhibits RGS3 signaling. Additionally, miR-126-3p levels were significantly higher in the serum of TTC patients compared to healthy controls and patients who had recovered from TTC. Conclusions Our study is the first to reveal that exosomal miR-126-3p, originating from endothelial cells, contributes to ion channel dysfunction by regulating RGS3 signaling in cardiomyocytes. These findings provide new perspectives on the pathogenesis of TTC and suggest potential therapeutic targets for treatment. Graphical Abstrac
The formation of chaperone-rich GET bodies depends on the tetratricopeptide repeat region of Sgt2 and is reversed by NADH
No full textThe guided-entry of tail-anchored proteins (GET) pathway is a post-translational targeting route to the endoplasmic reticulum. Upon glucose withdrawal, the soluble GET proteins re-localize to dynamic cytosolic foci, here termed GET bodies. Our data reveal that the pre-targeting complex components, Sgt2 and the Get4-Get5 heterodimer, and the Get3 ATPase play important roles in the assembly of these structures. More specifically, the TPR region of Sgt2 is required as a GET body scaffold. Systematic compositional analyses of GET bodies reveal their chaperone-rich nature and the presence of numerous proteins involved in metabolic processes. Temporal analyses of GET body assembly demonstrate the sequential recruitment of different chaperones, and we discover the requirement of Sis1 and Sti1 for maintaining the dynamic properties of these structures. In vivo, NADH derived from the oxidation of ethanol to acetaldehyde can induce GET body disassembly in a reaction depending on the alcohol dehydrogenase Adh2 and in vitro, addition of NADH resolves GET bodies. This suggests a mechanistic basis for their formation and disassembly in response to the metabolic shift caused by glucose withdrawal and re-addition
The Potential Mechanism and the Role of Antioxidants in Mitigating Oxidative Stress in Alzheimer’s Disease
No full textAlzheimer’s disease (AD) is the most prevalent cause of dementia and a significant contributor to health issues and mortality among older individuals. This condition involves a progressive deterioration in cognitive function and the onset of dementia. Recent advancements suggest that the development of AD is more intricate than its underlying brain abnormalities alone. In addition, Alzheimer’s disease, metabolic syndrome, and oxidative stress are all intricately linked to one another. Increased concentrations of circulating lipids and disturbances in glucose homeostasis contribute to the intensification of lipid oxidation, leading to a gradual depletion of the body’s antioxidant defenses. This heightened oxidative metabolism adversely impacts cell integrity, resulting in neuronal damage. Pathways commonly acknowledged as contributors to AD pathogenesis include alterations in synaptic plasticity, disorganization of neurons, and cell death. Abnormal metabolism of some membrane proteins is thought to cause the creation of amyloid (Aβ) oligomers, which are extremely hazardous to neurotransmission pathways, especially those involving acetylcholine. The interaction between Aβ oligomers and these neurotransmitter systems is thought to induce cellular dysfunction, an imbalance in neurotransmitter signaling, and, ultimately, the manifestation of neurological symptoms. Antioxidants have a significant impact on human health since they may improve the aging process by combating free radicals. Neurodegenerative diseases are currently incurable; however, they may be effectively managed. An appealing alternative is the utilization of natural antioxidants, such as polyphenols, through diet or dietary supplements, which offer numerous advantages. Within this framework, we have extensively examined the importance of oxidative stress in the advancement of Alzheimer’s disease, as well as the potential influence of antioxidants in mitigating its effects
T1-relaxation times along the corticospinal tract as a diagnostic marker in patients with amyotrophic lateral sclerosis
No full textBackground and purpose In the differential diagnostic workup of amyotrophic lateral sclerosis (ALS), magnetic resonance imaging (MRI) is primarily used to rule out significant differential diagnoses. So far, whole-brain T1-mapping has not been assessed as a diagnostic tool in this patient population. Methods We investigated the diagnostic potential of a novel T1-mapping method based on real-time MRI with 0.5 mm in-plane resolution and 4s acquisition time per slice. The study included patients aged 18 to 90 years who met the revised El Escorial criteria for at least possible ALS. T1-relaxation times were measured along the corticospinal tract in predefined regions of interest. Results Twenty-nine ALS-patients and 43 control group patients (CG) were included in the study. Median ALS Functional Rating Scale revised (ALSFRS-R) was 37 (IQR, 35–44) points and the mean duration from symptom onset to MRI was 21 ± 17 (SD) months. ALS patients showed significantly higher T1-relaxation times in all ROIs compared to CG with mean differences in the hand knob of 50 ms ( p < 0.001), corona radiata 24 ms ( p = 0.034), internal capsule 27 ms ( p = 0.002) and midbrain peduncles 48 ms ( p < 0.001). There was a consistent negative correlation between the ALSFRS-R and T1-relaxation times in all ROIs. Conclusions T1-relaxation times along the corticospinal tract are significantly elevated in ALS patients compared to CG and associated with lower ALSFRS-R. These results imply the analysis of T1-relaxation times as a promising diagnostic tool that can distinguish ALS patients from the control group. Ongoing longitudinal studies may provide deeper insights into disease progression and the effects of therapeutic interventions.Open-Access-Publikationsfonds 202
How eccentricity modulates attention capture by direct face/gaze and sudden onset motion
No full textAbstract We investigated how processing benefits for direct face/gaze and sudden onset motion depend on stimulus presentation location, specifically eccentricity from fixation. Participants responded to targets that were presented on one of four stimuli that displayed a direct or averted face and gaze either statically or suddenly. Between participants, stimuli were presented at different eccentricities relative to central fixation, spanning 3.3°, 4.3°, 5.5° or 6.5° of the visual field. Replicating previous studies, we found processing advantages for direct (vs. averted) face/gaze and motion onset (vs. static stimuli). Critically, while the motion-onset advantage increased with increasing distance to the center, the face/gaze direction advantage was not significantly modulated by target eccentricity. Results from a control experiment with eye tracking indicate that face/gaze direction could be accurately discriminated even at the largest eccentricity. These findings demonstrate a distinction between the processing of basic facial and gaze signals and exogenous motion cues, which may be based on functional differences between central and peripheral retinal regions. Moreover, the results highlight the importance of taking specific stimulus properties into account when studying perception and attention in the periphery.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Julius-Maximilians-Universität Würzburg http://dx.doi.org/10.13039/50110000876
Bridging the 3D geometrical organisation of white matter pathways across anatomical length scales and species
No full textWe used diffusion MRI and x-ray synchrotron imaging on monkey and mice brains to examine the organisation of fibre pathways in white matter across anatomical scales. We compared the structure in the corpus callosum and crossing fibre regions and investigated the differences in cuprizone-induced demyelination in mouse brains versus healthy controls. Our findings revealed common principles of fibre organisation that apply despite the varying patterns observed across species; small axonal fasciculi and major bundles formed laminar structures with varying angles, according to the characteristics of major pathways. Fasciculi exhibited non-straight paths around obstacles like blood vessels, comparable across the samples of varying fibre complexity and demyelination. Quantifications of fibre orientation distributions were consistent across anatomical length scales and modalities, whereas tissue anisotropy had a more complex relationship, both dependent on the field-of-view. Our study emphasises the need to balance field-of-view and voxel size when characterising white matter features across length scales.Captital Region of Denmark Research FoundationEuropean Research CouncilLundbeck FoundationIndependent Research Fund DenmarkScleroseforeningen http://dx.doi.org/10.13039/100008361Lundbeck Foundatio
Extending the fossil record of late Oligocene non-biting midges (Chironomidae, Diptera) of New Zealand
No full textBackground The modern chironomid fauna of New Zealand is diverse, highly endemic and reflects a complex biogeographical history. This fauna has been important for developing phylogenetic and biogeographic concepts including Brundin’s writings on transantarctic relationships but until now the fossil record to support these reconstructions has been very limited. Here we describe the first fossil species of Chironomidae, subfamily Orthocladiinae, from New Zealand, based on inclusions in amber from the late Oligocene Pomahaka Formation of the South Island. Methods We examined newly excavated fossil tree resin (amber) from the late Oligocene Pomahaka Formation in southern New Zealand for inclusions. Amber pieces containing chironomids were prepared and morphologically investigated using light-microscopy and µCT-scanning. Specimens were taxonomically evaluated using identification keys for modern adult chironomid midges. Habitus and key morphological features of each specimen were documented photographically and/or by line drawings. Results Thirteen Chironomidae specimens from Pomahaka amber were identified as members of the subfamily Orthocladiinae Kieffer. Bryophaenocladius zealandiae sp. nov. Baranov is the first Southern Hemisphere fossil of the genus. Bryophaenocladius Thienemann, 1934 is absent from the extant fauna of the main islands of New Zealand; however, it may be present on the subantarctic Auckland Islands. Two incompletely preserved specimens are described as Morphotype 1 cf. Bryophaenocladius zealandiae . Based on a male adult, Pterosis extinctus sp. nov. Baranov is described as the first fossil record of the extant genus Pterosis Sublette and Wirth, today represented by a single endemic species on the New Zealand subantarctic Auckland Islands and Campbell Island. Two female adult specimens are described as Morphotype 2 cf. Metriocnemini. The new fossils of the genera Bryophaenocladius and Pterosis belong to chironomid taxa requiring terrestrial or semi-aquatic habitats for larval development, supporting the notion of a humid forest swamp paleoenvironment for the Pomahaka amber source forest
Feed the green for a sustainable and protein-efficient dairy production
No full texthttp://dx.doi.org/10.13039/501100010415 Federal Agency for Nature Conservatio