in-vitro-ovule-cultivation-for-live-cell-imaging-zygote-polarization

<em>In Vitro</em> Ovule Cultivation for Live-cell Imaging of Zygote Polarization and Embryo Patterning in <em>Arabidopsis thaliana</em>

In most flowering plants, the zygote and embryo are hidden deep in the mother tissue, and thus it has long been a mystery of how they develop dynamically; ...

Nagoya University

Microstructures of 3C-SiC grown by chemical vapor deposition (CVD) technique on undulant silicon substrate and a further developed technique called switch-back epitaxy (SBE) were studied using transmission electron microscopy (TEM). In case of the CVD sample, the density of the stacking faults was found to be significantly decreasing along growth direction. Sites of collision of stacking faults were observed using high-resolution transmission electron microscopy. Some of the stacking faults were observed to have disappeared after colliding into each other. The stacking faults were identified to be on the same type of plane and had the same type of displacement vector not only in CVD and SBE but also in the epitaxial layer on the SBE SiC samples.

Microstructure characterization of defects in cubic silicon carbide using transmission electron microscopy.

Cell proliferation is crucial to the growth of multicellular organisms, and thus the proper control of cell division is important to prevent developmental arrest or overgrowth. Nevertheless, tools for controlling cell proliferation are still poor in plant. To develop novel tools, we focused on a specific compound family, triarylmethanes, whose members show various antiproliferative activities in animals. By combining organic chemistry to create novel and diverse compounds containing the triarylmethyl moiety and biological screens based on live-cell imaging of a fluorescently labeled tobacco Bright Yellow-2 (BY-2) culture cell line (Nicotiana tabacum), we isolated (3-furyl)diphenylmethane as a strong but partially reversible inhibitor of plant cell division. We also found that this agent had efficient antiproliferative activity in developing organs of Arabidopsis thaliana without causing secondary defects in cell morphology, and induced rapid cell division arrest independent of the cell cycle stage. Given that (3-furyl)diphenylmethane did not affect the growth of a human cell line (HeLa) and a budding yeast (Saccharomyces cerevisiae), it should act specifically on plants. Taking our results together, we propose that the combination of desired chemical synthesis and detailed biological analysis is an effective tool to create novel drugs, and that (3-furyl)diphenylmethane is a specific antiproliferative agent for plants.

Combination of Synthetic Chemistry and Live-Cell Imaging Identified a Rapid Cell Division Inhibitor in Tobacco and Arabidopsis thaliana.

The asymmetric cell division of the zygote is the initial and crucial developmental step in most multicellular organisms. In flowering plants, whether zygote polarity is inherited from the preexisting organization in the egg cell or reestablished after fertilization has remained elusive. How dynamically the intracellular organization is generated during zygote polarization is also unknown. Here, we used a live-cell imaging system with Arabidopsis zygotes to visualize the dynamics of the major elements of the cytoskeleton, microtubules (MTs), and actin filaments (F-actins), during the entire process of zygote polarization. By combining image analysis and pharmacological experiments using specific inhibitors of the cytoskeleton, we found features related to zygote polarization. The preexisting alignment of MTs and F-actin in the egg cell is lost on fertilization. Then, MTs organize into a transverse ring defining the zygote subapical region and driving cell outgrowth in the apical direction. F-actin forms an apical cap and longitudinal arrays and is required to position the nucleus to the apical region of the zygote, setting the plane of the first asymmetrical division. Our findings show that, in flowering plants, the preexisting cytoskeletal patterns in the egg cell are lost on fertilization and that the zygote reorients the cytoskeletons to perform directional cell elongation and polar nuclear migration.

Article	Year
Microstructure characterization of defects in cubic silicon carbide using transmission electron microscopy. Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada\| PubMed ID: 23920188	2013
Combination of Synthetic Chemistry and Live-Cell Imaging Identified a Rapid Cell Division Inhibitor in Tobacco and Arabidopsis thaliana. Plant & cell physiology\| PubMed ID: 27519314	2016
Cytoskeleton dynamics control the first asymmetric cell division in Arabidopsis zygote. Proceedings of the National Academy of Sciences of the United States of America\| PubMed ID: 27911812	2016

Yusuke Kimata

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