Browsing by Subject "Tracheary cells"
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Item Development of methodology for freeze-substitution and immunolocalization in differentiating tracheary elements of Zinnia elegans(Texas Tech University, 1998-05) Muehring, Trina CelesteIn higher plants, redifferentiation occurs when one cell type transforms into another with an associated change in cell function. Xylem tissue is formed either in this manner, from parenchyma cells, or by de novo differentiation from procambium/cambium initials. Tracheary elements (TEs) are water-conducting cells in xylem tissue. Dead at maturity, these elements connect end to end to form a transport system In culture, parenchyma cells have been shown to redifferentiate into tracheary elements, forming secondary wall patterns by locahzed thickenings (Kohlenbach et al., 1981) (see Figs. 1.1 and 1.2). Zinnia elegans has become a model system by which to study TE differentiation because single cells can be induced to form TEs in culture. Present in only specialized cell types such as TEs, the secondary cell wall is laid down inside the primary ceU waU under cytoskeletal control. The control of secondary wall development is not well defined. Actin and microtubules are two cytoskeletal elements that theory and observations predict will be involved in this process. Research with antibodies in the Zinnia system can reveal whether or not any pattem is recognizeable before the secondary wall thickenings appear and the morphological stages can then be identified that represent the estabhshment of that pattem. "The possible role of cytoskeletal elements in regulating microfibril organization remains one of the central unresolved questions in plant cell biology... diflSculty arises in proving that the cytoskeleton is essential for the organized deposition of wall microfibrils" (Seagull 1989. p. 145). The focus of this research is to optimize uhra rapid freezing methods so that routine experiments performed on Zinnia TEs will resuh in state-of-the-art preservation of cytoplasm and immuno-gold labeUng by antibodies.Item The isolation and characterization of partial cDNAs associated with In Vitro tracheary element formation(Texas Tech University, 1995-08) Koonce, Linda TDifferential Display provides a sensitive method for quickly isolating and cloning cDNAs with corresponding mRNA transcripts that are differentially expressed between two different tissues or cell t5rpes. This technique provided a means by which three cDNAs with corresponding transcripts that are strongly expressed in suspension cultures of Zinnia mesophyll cells differentiating into tracheary elements were isolated. One transcript (63.30) has similarity to the non-histone protein 2 high mobility group-like protein in yeast, and to ribosomal proteins from yeast and the PRL2 protein from A. thaliana. The 63.30 transcript was found to be expressed in newly forming tracheary elements and phloem fibers and is expressed in response to auxin and/or cytokinin. A second transcript (54.6) was also determined to be expressed in newly forming tracheary elements and phloem fibers and is expressed in response to auxin and/or cytokinin. The deduced protein sequence of the 54.6 transcript shares some similarity to membrane spanning domains and the voltage sensor domain of the alpha subunit of the dihydropyridine- sensitive voltage-dependent calcium channel isolated from rat aorta. A third cDNA was isolated and expression of the transcript was found in in vitro differentiating tracheary elements, but no expression was detected in any whole plant tissue. It is possible that this transcript is a very rare species or is a result of the stress of culturing. No similarities to this transcript were detected by searches of the Blast/NCBI databases.Item The role of calcium ions in the differentiation of tracheary elements from isolated cells in suspension culture(Texas Tech University, 1990-05) Roberts, Alison Wille.Item Tracheary transition from root to stem in Phaseolus species(Texas Tech University, 1968-06) Sprott, Margaret ErikssonNot available