Project description:We used isobaric tags for relative and absolute quantitation (iTRAQ) to perform a quantitative proteomic analysis of immature spikes harvested from tetraploid near-isogenic lines of wheat with normal spikelete (NSs), FRSs, and RSs and investigated the molecular mechanisms of lateral meristem differentiation and development. This work provides valuable insight into the underlying functions of the lateral meristem and how it can produce differences in the branching of tetraploid wheat spikes.
Project description:affy_brachy_2011_11 - affy_brachy_2011_11 - Fusarium graminearum is the causal agent of Fusarium head blight (FHB) of small-grain cereals, including wheat. Besides direct grain losses, this disease is of major concern because of the production by the pathogen of mycotoxins which are hazardous to animals, thus making the grain unfit for food or feed. Major mycotoxins produced by the fungus are trichothecens, including deoxynivalenol (DON). In our laboratory, we use Brachypodium distachyon as a model plant for cereals because of its amenability (short life cycle, numerous genomic and genetic resources, ...). We have recently shown that F. graminearum does induce head blight symptoms on this species and that DON is produced on infected spikes. We have also evidenced that a F. graminearum strain unable to produce DON exhibits reduced virulence on B. distachyon spikes, as previously shown on wheat. The aim of this project is to analyse and compare the plant response to DON producing and non-producing strains of F. graminearum. This analysis will allow to decipher the mechanisms of detoxification set up by the plant and also more specific responses due to the impact of the mycotoxin on plant metabolism and physiology. -Three conditions on B. distachyon spikes: 1-Mock inoculation (Tween 20 0,01%) 2-Inoculation by a F. graminearum wild-type strain 3-Inoculation by a F. graminearum mutant strain, unable to produce DON Spikes were point inoculated with 3ul of either Tween 20 0.01%, wild-type strain or mutant strain (300 spores) and incubated for 96 hours. Six inoculated spikes were collected and pooled for each condition and biological replicate. Three independent biological replicates were conducted.
Project description:To get an overview of transcriptome characteristics of Wangshuibai during infection by Fg, a high-throughput RNA sequencing based on next generation sequencing (NGS) technology (Illumina) were performed. Each spike of 4 central spikelets was injected with 10 μl of conidial inoculant (105 macro conidia per milliliter) and covered with a plastic bag to maintain humidity until sampling. Both non-inoculated spikes and inoculated spikes at 12, 24, 48, 72 and 96 hours after inoculation (hai) were sampled. Inoculations and sampling were conducted at 7 a.m. except for the sample at 12 hai at 7 p.m. A total of 12 samples (one treatment, two genotypes and six time points) were prepared for RNA extraction. The samples for transcriptome analysis were the mixture of equal amount of RNA from non-inoculated spikes and spikes at 12, 24 and 48 hai of Wangshuibai. Transcriptome library with fragments between 200 to 700 bp was prepared following the Illuminaâs kits provided by manufacturer and sequenced on Illumina HiSeq⢠2000 using paired-end technology in a single run.
Project description:The number of circulating endothelial progenitor cells (EPCs) predicts future development of atherosclerotic cardiovascular disease (ASCVD) and is reduced in patients with type 2 diabetes (T2DM) or impaired glucose tolerance (IGT). Recent studies revealed the contribution of tight control of glycolysis and mitochondrial oxidative phosphorylation (OXPHOS), as well as fatty acid oxidation in the regulation of stem cell behavior. In this study, we show that how dysregulated glucose and triglyceride metabolism in T2DM/IGT affects the homeostasis of EPCs, i.e. bone marrow stem/progenitor cells (BMSCs). In our clinical study, consistent with previous reports, the patients with IGT or T2DM showed reduced level of circulating EPCs, as compared normal glucose tolerance. On the other hand, fasting or postprandial hypertriglyceridemia (hTG) itself did not affect the level of circulating EPCs. However, further analysis using single and multiple regression analyses strongly suggested that, in the presence of postprandial hTG, postprandial hyperglycemia exerts devastating effect on EPC homeostasis. We therefore carried out the proof of concept study in mice. Our experimental study revealed that repetitive glucose+lipid (G+L) spikes, but not repetitive glucose (G) spikes or lipid (L) spikes, rapidly upregulated p53 in BMSCs and induced premature aging phenotype of bone marrow cells, i.e. the impairment of BMSC quiescence and function, and myeloid-biased differentiation. Subsequent analysis implicated that p53-mediated augmentation of mitochondrial OXPHOS plays pivotal role for the impairment of BMSC quiescence and function. On the other hand, it is still not clear how repetitive G+L injection induced myeloid-biased differentiation. Because cell-fate decisions are executed by transcription factors in response to extracellular signals, and the best-known function of p53 is as a transcription factor, we asked to what extent repetitive glucose spikes and repetitive glucose+TG spikes affect transcriptional regulation in LSK cells.
Project description:The spike glycoprotein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mediates binding to the ACE2 receptor and subsequent membrane fusion. It exists in a range of conformations, including a closed state unable to bind the ACE2 receptor, and an open state that does so but displays more exposed antigenic surface. Spikes of variants of concern (VOCs) acquired amino acid changes linked to different opening probabilities, increased SARS-CoV-2 virulence and immune evasion. Here, using hydrogen-deuterium exchange mass spectrometry (HDX-MS), we analyzed the spike of the original Wuhan isolate, G614 mutant, spike of alpha, beta, delta and omicron VOCs and the isolated ancestral receptor binding domain (RBD) - in apo state and in complex with the ACE2 receptor. We identified changes in spike dynamics that we associated with the transition from closed to open conformation, to ACE2 binding, and to specific mutations in VOCs. We show that the RBD-associated subdomain plays a role in spike opening, whereas the NTD acts as a hotspot of conformational divergence of VOC spikes driving immune evasion. Alpha, beta and delta spikes assume predominantly open conformations and a strong ACE2 binding increases the dynamics of their core helices, priming spikes for fusion. Conversely, substitutions in omicron spike lead to predominantly binding-incompetent closed conformations, presumably enabling it to escape antibodies. At the same time, its core helices show characteristics of being pre-primed for fusion even in the absence of ACE2. These data inform on SARS-CoV-2 evolution and omicron variant emergence.
Project description:The spike glycoprotein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mediates binding to the ACE2 receptor and subsequent membrane fusion. It exists in a range of conformations, including a closed state unable to bind the ACE2 receptor, and an open state that does so but displays more exposed antigenic surface. Spikes of variants of concern (VOCs) acquired amino acid changes linked to different opening probabilities, increased SARS-CoV-2 virulence and immune evasion. Here, using hydrogen-deuterium exchange mass spectrometry (HDX-MS), we analyzed the spike of the original Wuhan isolate, G614 mutant, spike of alpha, beta, delta and omicron VOCs and the isolated ancestral receptor binding domain (RBD) - in apo state and in complex with the ACE2 receptor. We identified changes in spike dynamics that we associated with the transition from closed to open conformation, to ACE2 binding, and to specific mutations in VOCs. We show that the RBD-associated subdomain plays a role in spike opening, whereas the NTD acts as a hotspot of conformational divergence of VOC spikes driving immune evasion. Alpha, beta and delta spikes assume predominantly open conformations and a strong ACE2 binding increases the dynamics of their core helices, priming spikes for fusion. Conversely, substitutions in omicron spike lead to predominantly binding-incompetent closed conformations, presumably enabling it to escape antibodies. At the same time, its core helices show characteristics of being pre-primed for fusion even in the absence of ACE2. These data inform on SARS-CoV-2 evolution and omicron variant emergence.