CA
Carsten P Ade
  • University of Würzburg
Research fields
  • Cancer biology
Monitoring Xylem Hydraulic Pressure in Woody Plants
Xylem sap circulates under either positive or negative hydraulic pressure in plants. Negative hydraulic pressure (i.e., tension) is the most common situation when transpiration is high, and several devices have been developed to quantify it accurately (e.g., Scholander pressure chamber, psychrometers). However, a proper measurement of positive xylem sap pressures may be critical when pressure is generated by the root system, allowing vessels to be refilled. Here, we describe two different methods to monitor positive xylem bulk pressure: the pressure gauge which can only be set onto a rootstock or a side branch and the point pressure sensor, which can allow measurements from a functioning plant without detopping or cutting.
Analysis of 3D Cellular Organization of Fixed Plant Tissues Using a User-guided Platform for Image Segmentation
Authors:  Ethel Mendocilla Sato and Célia Baroux, date: 06/20/2017, view: 10972, Q&A: 0
The advent of non-invasive, high-resolution microscopy imaging techniques and computational pipelines for high-throughput image processing has contributed to gain insights in plant organ morphogenesis at the cellular level. Confocal scanning laser microscopy (CSLM) allows the generation of three dimensional images constituted of serial optical sections reporting on stained subcellular structures. Fluorescent labels of cell walls or cell membranes, either chemically or through reporter proteins, are particularly useful for the analyses of tissue organization and cellular shapes in 3D. Image segmentation based on cell boundary signals is used as an input to generate 3D-segments representing cells. These digitalized, 3D objects provide quantitative data on cell shape, size, geometry, position or on (intercellular) intensity signals if additional reporters are used. Herein, we report a detailed, annotated workflow for image segmentation using microscopic data. We used it in the context of a study of tissue patterning during ovule primordium development in Arabidopsis thaliana. Whole carpels are stained for cell boundaries using a modified pseudo-Schiff propidium iodide (mPS-PI) protocol, 3D images are acquired at high resolution by CSLM, segmented and annotated for individual cell types using ImarisCell. This allows for quantitative analyses of cell shape and cell number that are relevant for tissue morphodynamic studies.
Determination of Rate of [3H-methyl]-choline Incorporation into Cellular Lipids and Non-lipid Metabolites
Authors:  Tim Andrew Davies Smith and Su Myat Phyu, date: 11/20/2016, view: 7047, Q&A: 0
The choline-containing phospholipid, phosphatidylcholine (PtdCho) is the most common mammalian phospholipid found in cell membrane (Ide et al., 2013). It is also a component of intracellular signalling pathways (Cui and Houweling, 2002). Herein is described a measure of the rate of accumulation of choline by lipid soluble PtdCho and lyso-Ptdcho which can further be discriminated by chromatographic analysis (Smith and Phyu, 2016). Determination of the accumulation of [3H-methyl]-choline into water-soluble components is also described. The procedure could be used to measure the effect of drugs and other factors on choline incorporation into phospholipids. After exposure of cells to test conditions (e.g., drugs) adherent cells in tissue culture flasks are incubated with radiolabelled [3H-methyl]-choline in medium for 15 min (pulse). The [3H-methyl]-choline is then rapidly removed and incubation continued in the presence of non-radioactive medium (chase). Cellular distribution of [3H-methyl] is then determined by cell fractionation and measurement of radioactivity in the lipid and non-lipid cellular components.
Immunogold Labeling Analysis of Cell Wall Polysaccharides with Special Reference to (1;3,1;4)-β-D-glucan in Rice Cell Walls
Various types of cell wall compositions have evolved to fulfill a wide range of biological roles during the diversification of land plants. (1;3,1;4)-β-D-glucan (MLG) is a defining feature of the cell walls in the order Poales (Yokoyama and Nishitani, 2004), which has multiple functions associated with metabolic, growth, and defense systems. MLG is also a characteristic component of the matrix polysaccharides that undergo turnover and metabolism, depending on the tissue and the stage of development (Kido et al., 2015). Determining the extracellular localization of MLG is essential for elucidating its functions. Electron microscopy immunogold labeling analysis is a useful technique, which provides an accurate representation of the extracellular distribution of MLG. This strategy is also applicable to various kinds of cell wall polysaccharides, which have key roles in regulating growth and differentiation in each plant species.
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