Project description:Characterization of microbial communities in floor drain biofilms and drain waters in a Listeria monocytogenes-contaminated food processing environment
Project description:Source-to-sink carbon (C) allocation driven by the sink strength, i.e., the ability of a sink organ to import C, plays a central role in tissue growth and biomass productivity. However, molecular drivers of sink strength have not been thoroughly characterized in trees. Auxin, as a major plant phytohormone, regulates the mobilization of photoassimilates in source tissues and elevates the translocation of carbohydrates toward sink organs, including roots. In this study, we used an ‘auxin-stimulated carbon sink’ approach to understand the molecular processes involved in the long-distance source-sink C allocation in poplar. Poplar cuttings were foliar sprayed with polar auxin transport modulators, including auxin enhancers (AE) (i.e., IBA and IAA) and auxin inhibitor (AI) (i.e., NPA), followed by a comprehensive analysis of leaf, stem, and root tissues using biomass evaluation, phenotyping, C isotope labeling, metabolomics, and transcriptomics approaches. Auxin modulators altered root dry weight and branching pattern, and AE increased photosynthetically fixed C allocation from leaf to root tissues. The transcriptome analysis identified highly expressed genes in root tissue under AE condition including transcripts encoding polygalacturonase and β-amylase that could increase the sink size and activity. Metabolic analyses showed a shift in overall metabolism including an altered relative abundance levels of galactinol, and an opposite trend in citrate levels in root tissue under AE and AI conditions. In conclusion, we postulate a model suggesting that the source-sink C relationships in poplar could be fueled by mobile sugar alcohols, starch metabolism-derived sugars, and TCA-cycle intermediates as key molecular drivers of sink strength.
Project description:Soybean plants that do not produce a sink, such as depodded or male sterile plants, exhibit physiological and morphological changes during the reproductive stages, including increased levels of nitrogen and starch in the leaves and a delayed senescence. To identify transcriptional changes that occur in leaves of sink-limited plants, we used RNAseq to compare gene expression levels in trifoliate leaves from depodded and ms6 male sterile plants and control plants. In sink-limited tissues, we observed a deferral of the expression of senescence-associated genes and a continued high expression of genes associated with the maturity phase of leaf development. We identified GO-terms associated with growth and development and storage protein in sink limited tissues. We also identified that the bHLH. ARFs, and SBP transcription factors were expressed in sink limited tissues while the senescing control leaves expressed WRKY and NAC transcription factors. We identified genes that were not expressed during normal leaf development but highly expressed in sink-limited plants, including the D4 “non-yellowing” gene. These changes highlighted several metabolic pathways that were involved in distinct modes of resource parttioning in the “stay green” leaves.
Project description:The objective of the study was to characterize distinct endotypes of asthma related to damp and moldy buildings and to evaluate the potential molecular similarities with idiopathic environmental intolerance (IEI). The nasal biopsy transcriptome of 88 study subjects was profiled using samples obtained at baseline.
Project description:To examine the role of formation of a strong sink during leaf senescence, we compared the expression profile of the flag leaf of three different sterile mutant lines with fertile plants. The fertile and sterile lines showed basically similar expression profiles of flag leaves sampled at the same time. However, the fertile lines showed more rapid and enhanced change in transcriptome as compared to the sterile lines indicating that leaf senescence initiated independent of sink formation and is accelerated by sink formation.