Project description:Seed of 4 lines of S. tuberosum var andigena were sown and, after transplanting, grown in 3 gal nursery containers in a greenhouse with natural daylight. The seeds were sown in July and the drought stress experiment began in September. Drought stress was administered by withholding water and monitored by measuring the rate of photosynthesis (PS; LiCor 6400). We found that loss of photosynthetic capability (ie a PS rate of 0-2 mM CO2/m2/sec) correlated with a severe drought stress. Control plants were watered normally and maintained a PS rate of 18-20 mM CO2/m2/sec. After drought stress, the treated plants were re-watered and PS measurements taken again. After the first cycles of stress, control and treated plants were harvested and roots, tubers and shoots were stored at –80°C for RNA extractions. The drought experiment was then repeated for the remaining plants such that they were exposed to a second cycle of stress. For each line of S. andigena, there were 2 control and 2 treated plants per cycle of stress. RNA was extracted following the acid phenol protocol of TIGR. Keywords: Direct comparison, loop design
Project description:Understanding ecological linkages between above- and below-ground biota is critical for deepening our knowledge on the maintenance and stability of ecosystem processes. Nevertheless, direct comparisons of plant-microbe diversity at the community level remain scarce due to the knowledge gap between microbial ecology and plant ecology. We compared the ?- and ?- diversities of plant and soil bacterial communities in two temperate forests that represented early and late successional stages. We documented different patterns of aboveground-belowground diversity relationships in these forests. We observed no linkage between plant and bacterial ?-diversity in the early successional forest, and even a negative correlation in the late successional forest, indicating that high bacterial ?-diversity is not always linked to high plant ?-diversity. Beta-diversity coupling was only found at the late successional stage, while in the early successional forest, the bacterial ?-diversity was closely correlated with soil property distances. Additionally, we showed that the dominant competitive tree species in the late successional forest may play key roles in driving forest succession by shaping the soil bacterial community in the early successional stage. This study sheds new light on the potential aboveground-belowground linkage in natural ecosystems, which may help us understand the mechanisms that drive ecosystem succession.
Project description:Biological heterogeneity in diffuse large B cell lymphoma (DLBCL) is partly driven by cell-of-origin subtypes and associated genomic lesions, but also by diverse cell types and cell states in the tumor microenvironment (TME). However, dissecting these cell states and their clinical relevance at scale remains challenging. Here, we implemented EcoTyper, a machine learning framework integrating transcriptome deconvolution and single-cell RNA sequencing, to characterize clinically relevant DLBCL cell states and ecosystems. Using this approach, we identified five cell states of malignant B cells that vary in prognostic associations and differentiation status. We also identified striking variation in cell states for 12 other lineages comprising the TME and forming cell-state interactions in stereotyped ecosystems. While cell-of-origin subtypes have distinct TME composition, DLBCL ecosystems capture clinical heterogeneity within existing subtypes and extend beyond cell-of-origin and genotypic classes. These results resolve the DLBCL microenvironment at unprecedented resolution and identify opportunities for therapeutic targeting (https://ecotyper-stanford-edu.stanford.idm.oclc.org/lymphoma).
Project description:Biological heterogeneity in diffuse large B cell lymphoma (DLBCL) is partly driven by cell-of-origin subtypes and associated genomic lesions, but also by diverse cell types and cell states in the tumor microenvironment (TME). However, dissecting these cell states and their clinical relevance at scale remains challenging. Here, we implemented EcoTyper, a machine learning framework integrating transcriptome deconvolution and single-cell RNA sequencing, to characterize clinically relevant DLBCL cell states and ecosystems. Using this approach, we identified five cell states of malignant B cells that vary in prognostic associations and differentiation status. We also identified striking variation in cell states for 12 other lineages comprising the TME and forming cell-state interactions in stereotyped ecosystems. While cell-of-origin subtypes have distinct TME composition, DLBCL ecosystems capture clinical heterogeneity within existing subtypes and extend beyond cell-of-origin and genotypic classes. These results resolve the DLBCL microenvironment at unprecedented resolution and identify opportunities for therapeutic targeting (https://ecotyper-stanford-edu.stanford.idm.oclc.org/lymphoma).
Project description:Plants are primary producers of food and oxygen on Earth and will likewise be indispensable to the establishment of large-scale sustainable ecosystems and human survival in space. To contribute to the understanding of how plants respond to spaceflight stresses, we examined the relevance of the unfolded protein response (UPR), a conserved signaling cascade that responds to a number of unfavorable environmental stresses, in the model plant species Arabidopsis thaliana. To do so, we compared the transcriptional responses of wild type and UPR-defective seedlings to spaceflight during the SpaceX-CRS12 mission to the International Space Station. We established that orbital culture substantially altered the expression of hundreds of stress related genes compared to ground control conditions. Although many of these genes were differentially regulated in the UPR mutants in the ground control conditions compared to wild type, their expression was largely equalized in all genotypes by flight. Our results have yielded new information on how plants respond to growth in orbit and support the hypothesis that spaceflight induces the activation of signaling pathways that compensate for the loss of UPR regulators in the control of downstream transcriptional regulatory networks.
Project description:Fe-IMAC columns for robust and reproducible phosphopeptide ernichment, comparison to TiO2 batch and Ti-IMAC tip enrichment, large scale phosphoproteomics coupling Fe-IMAC column pre-enrichment to subsequent hSAX separation
Project description:Young Fagus sylvatica trees (approximately 7 to 8 years) were collected from a natural regeneration beech forest. The trees were excavated with intact soil cores, roots and top organic layer. The trees were then kept outdoors at the Department of Forest Botany, Georg-August-Universität Göttingen. Plants were protected from rain, and light conditions were matched to those of the natural stand using a shading net; otherwise, plants were exposed to natural climatic conditions. The soil moisture was regularly measured; plants were watered with deionized water as needed to keep soil moisture close to the original conditions. Trees was randomly relocated on a weekly basis throughout the experiment to avoid biasses caused by location or light effects. After 21 weeks, a treatment was applied to understand the physiological mechanisms of inorganic nitrogen uptake and assimilation under conditions of an inorganic nitrogen saturated forest simulation: Plants were fertilized with either a 20 mM solution of KNO3, a 20 mM solution of NH4Cl, or demineralized water (control) for 2 days. On the third day, the trees were harvested. Root tips were immediately shock-frozen in liquid nitrogen and used for RNA extraction.