Biology subjects

Roesch, M.

Publications and source records attributed to Roesch, M..

5 recordsLinked to original sources

bioRxiv2024

Sequencing of historical plastid genomes reveal exceptional genetic diversity in early domesticated rye plants

In medieval central Europe, rye was one of the most important agricultural crops. Its properties of frost resistance, general resilience and resistance to many pathogens made it invaluable for medieval farmers. Rye has a distinct domestication history compared to other cereal crops and was not domesticated directly from its wild ancestors, like barley and wheat. Rye is considered to be a "secondary domesticate", i.e. a crop with domestication traits that initially evolved as an arable weed but eventually was intentionally sown and propagated as a crop. To study the history of rye domestication, genetic sequences of present-day plant populations as well as material from historical samples can provide insights into the temporal and spatial signatures of domestication. In this study we combined archaeobotanical methods and ancient DNA sequencing of well-preserved, historical rye material to study patterns of genetic diversity across four centuries. We first applied archaeobotanical methods to characterize rye material acquired from construction material ranging from the 14th to 18th century from different locations in Germany. Next, we extracted DNA to sequence complete chloroplast genomes of six individual samples. We compared the 115,000 bp chloroplast genomes of historical rye samples to chloroplast genomes of other cereal crops and identified 217 single nucleotide variants exclusive to historical samples. By comparing the aDNA chloroplast samples with modern rye chloroplasts, we show that the genetic variation in ancient rye populations was exceptionally high compared to samples from contemporary rye cultivars. This confirms that late domestication and selective breeding have reduced genetic variation in this important crop species only in the last few centuries. HighlightsO_LIHistorical plant material covering four centuries was obtained from half-timbered houses from five locations in Germany C_LIO_LIIntegrative archaeobotanical analyses and ancient DNA sequencing provided insights into genetic diversity of rye plants from historical farmland fields. C_LIO_LISequence analyses of complete assembled chloroplast genomes reveal expectational diversity in rye populations. C_LIO_LILate domestication of rye preserved genetic diversity over centuries. The more recent intensification of rye breeding has however conferred a considerable loss of genetic diversity in this important crop. C_LI

evolutionary biology↗

bioRxiv2023

TREM2 limits necrotic core formation during atherogenesis by controlling macrophage survival and efferocytosis

Atherosclerosis is a chronic disease of the vascular wall driven by lipid accumulation and inflammation in the intimal layer of arteries [1], [2], and its main complications, myocardial infarction and stroke, are the leading cause of mortality worldwide [3]. Recent studies have identified Triggering receptor expressed on myeloid cells 2 (TREM2), a lipid-sensing receptor regulating several key myeloid cell functions [4], as a highly expressed marker of macrophage foam cells in experimental and human atherosclerosis [5]. However, the function of TREM2 in the development of atherosclerosis is unknown. Here, we show that hematopoietic or global TREM2 deficiency increases necrotic core formation in early experimental atherosclerosis. We further demonstrate that TREM2 is essential for the efferocytosis capacities of macrophages, and to the survival of lipid-laden macrophages, altogether indicating a crucial role of TREM2 in maintaining the balance between foam cell death and their clearance in atherosclerotic lesions, thereby controlling plaque necrosis.

immunology↗

bioRxiv2023

A bird's-eye view: Evaluating drone imagery for the detection and monitoring of endangered and invasive day gecko species

Herpetofauna monitoring can be strongly limited by terrain accessibility, impeding our understanding of species ecology and thus challenging their conservation. This is particularly true for species living in the canopy, on cliffs or in dense vegetation. Remote sensing imagery may fill this gap by offering a cost-effective monitoring approach allowing to improve species detection in inaccessible areas. We investigated the applicability of drone-based monitoring for a Critically Endangered insular gecko (Phelsuma inexpectata) and two invasive alien species representing a risk for the former (P. grandis and P. laticauda). We determined the approach distance before inducing behavioural response caused by the drones presence. All three study species showed no reaction to the drones presence until very close distances (mean distance for P. inexpectata: 33.8 cm; P. grandis: 21.9 cm; P. laticauda: 26.4 cm). We then performed horizontal and vertical approaches, taking photos every meter starting at 10 m away from the canopy edge to determine an optimal distance for detection while ensuring species-level identification. We examined a total of 328 photos. We found a bimodality in the number of detected geckos, with different individuals recorded between short and intermediate distances. Therefore, we recommend taking photos at two distances of 2-2.5 m and 5 m away from the canopy, ideally facing away from the sun and in low wind conditions. We encourage the application of our methodology for Phelsuma spp., but also for other species of similar size and ecology to improve detection in inaccessible areas.

ecology↗

bioRxiv2021

Here be dragons: important spatial uncertainty driven by climate data in forecasted distribution of an endangered insular reptile

The effect of future climate change is poorly documented in the tropics, especially in mountainous areas. Yet, species living in these environments are predicted to be strongly affected. Newly available high-resolution environmental data and statistical methods enable the development of forecasting models. Nevertheless, the uncertainty related to climate models can be strong, which can lead to ineffective conservation actions. Predicted studies aimed at providing conservation guidelines often account for a range of future climate predictions (climate scenarios and global circulation models). However, very few studies considered potential differences related to baseline climate data and/or did not account for spatial information (overlap) in uncertainty assessments. We modelled the environmental suitability for Phelsuma borbonica, an endangered reptile native to Reunion Island. Using two metrics of species range change (difference in overall suitability and spatial overlap), we quantified the uncertainty related to the modelling technique (n = 10), sample bias correction, climate change scenario, global circulation models (GCM) and baseline climate (CHELSA versus Worldclim). Uncertainty was mainly driven by GCMs when considering overall suitability, while for spatial overlap the uncertainty related to baseline climate became more important than that of GCMs. The uncertainty driven by sample bias correction and variable selection was much higher when assessed based on spatial overlap. The modelling technique was a strong driver of uncertainty in both cases. We eventually provide a consensus ensemble prediction map of the environmental suitability of P. borbonica to identify the areas predicted to be the most suitable in the future with the highest certainty. Predictive studies aimed at identifying priority areas for conservation in the face of climate change need to account for a wide panel of modelling techniques, GCMs and baseline climate data. We recommend the use of multiple approaches, including spatial overlap, when assessing uncertainty in species distribution models.

ecology↗

bioRxiv2019

Time-resolved single-cell transcriptomics uncovers dynamics of cardiac neutrophil diversity in murine myocardial infarction

ObjectiveAfter myocardial infarction, neutrophils rapidly and massively infiltrate the heart, where they can promote both tissue healing and damage. Here, we investigated the dynamics of cardiac neutrophil heterogeneity after infarction.\n\nMethods and resultsWe employed single-cell transcriptomics (scRNA-seq) to investigate temporal neutrophil heterogeneity in the heart after murine myocardial infarction. At day 1, 3, and 5 after infarction, neutrophils could be delineated into six distinct clusters with specific time-dependent patterning and proportions. While the majority of neutrophils at day 1 were characterized by high expression of chemokines (e.g. Cxcl3, Ccl6), and putative activity of transcriptional regulators involved in hypoxic response (Hif1a) and emergency granulopoiesis (Cebpb), two major subsets of Siglecfhi (enriched for e.g. Icam1 and Tnf) and Siglecflow (Slpi, Ifitm1) neutrophils were found at 3 and 5 days. Flow cytometry analysis confirmed the presence of LY6G+SIGLECFhi and LY6G+SIGLECFlow neutrophils in the heart from 3 days after infarction onwards. LY6G+SIGLECFhi neutrophils were absent from the bone marrow, blood and spleen, suggesting local acquisition of surface SIGLECF. Acquisition of the SIGLECFhi state was paralleled by features of neutrophil ageing and activation (ICAM1hiCXCR4hiCD49dhiCD62Llow). scRNA-seq of atherosclerotic aortas revealed two neutrophil subsets with gene expression patterns reminiscent of the major Siglecfhi and Siglecflow cardiac neutrophil subpopulations, revealing that these populations may be present across distinct contexts of cardiovascular inflammation.\n\nConclusionAltogether, our data provide a time-resolved census of neutrophil diversity and gene expression dynamics in the mouse ischemic heart at the single-cell level, and suggests that temporal neutrophil heterogeneity is in part driven by local transition to a SIGLECFhi state.

immunology↗