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Full-Text Articles in Cell Biology

The Epidermis Still In Control?, Winfried Peters, A. Tomos Aug 1996

The Epidermis Still In Control?, Winfried Peters, A. Tomos

Winfried S. Peters

This paper has no abstract; these are the first two paragraphs. The search for a molecular mechanism of auxin action has rendered the “Auxin-Binding-Protein 1” (ABP-1) the top candidate for a functional auxin receptor (Venis and Napier, 1995), although its status remains disputed (Jones, 1994; Hertel, 1995; Napier, 1995; Venis, 1995). ABP-1 had long been thought to be localized exclusively in epidermal cells in coleoptiles (Löbler and Klämbt, 1985), and thus had fitted nicely the “epidermal-growth-control-hypothesis” (Kutschera, 1987, 1992). The recent report from the same lab of its uniform distribution throughout the coleoptile (Kayser and Klämbt, 1995) not only rises ...


The History Of Tissue Tension, Winfried S. Peters, A. Deri Tomos Jun 1996

The History Of Tissue Tension, Winfried S. Peters, A. Deri Tomos

Winfried S. Peters

In recent years the phenomenon of tissue tension and its functional connection to elongation growth has regained much interest. In the present study we reconstruct older models of mechanical inhomogenities in growing plant organs, in order to establish an accurate historical background for the current discussion. We focus on the iatromechanic model developed in Stephen Hales' Vegetable Staticks, Wilhelm Hofmeister's mechanical model of negative geotropism, Julius Sachs' explanation of the development of tissue tension, and the differential-auxin-response-hypothesis by Kenneth Thimann and Charles Schneider. Each of these models is considered in the context of its respective historic and theoretical environment ...


A Comparative Study Of The Binding Of Two Lectins In The Early Development Of The Freshwater Sponge, Ephydatia Mulleri, Jay Taylor Apr 1996

A Comparative Study Of The Binding Of Two Lectins In The Early Development Of The Freshwater Sponge, Ephydatia Mulleri, Jay Taylor

Life and Environmental Sciences Undergraduate Theses

Carbohydrates have been implicated in cell adhesion and in developmental processes. Lectin histochemistry using ConcanavalinA and Lotus lectin was used to localize lectin-accessible mannosyl and fucosyl residues in a maturing sponge developing from histoblasts generated during germination of a gemmule. With the exception of cystencytes found in the sponges stained with Lotus lectin, a similar staining pattern was seen with the two lectins, but there was a rather significant difference in the intensity of staining. This difference in staining intensity was thought to be a result of either more mannosyl residues available to the lectin or that the concentration of ...


A Novel, Mitogen-Activated Nuclear Kinase Is Related To A Drosophila Developmental Regulator, Gerald V. Denis, Michael R. Green Feb 1996

A Novel, Mitogen-Activated Nuclear Kinase Is Related To A Drosophila Developmental Regulator, Gerald V. Denis, Michael R. Green

Open Access Articles

Although the ultimate targets of many signal transduction pathways are nuclear transcription factors, the vast majority of known protein kinases are cytosolic. Here, we report on a novel human kinase that is present exclusively in the nucleus. Kinase activity is increased upon cellular proliferation and is markedly elevated in patients with acute and chronic lymphocytic leukemias. We have identified a human gene that encodes this nuclear kinase and find that it is closely related to Drosophila female sterile homeotic (fsh), a developmental regulator with no known biochemical activity. Collectively, these results suggest that this nuclear kinase is a component of ...


Reconstruction Of Ribosomal Subunits And Rdna Chromatin Imaged By Scanning Force Microscopy, Wolfgang Fritzsche, Linda Martin, Drena Dobbs, Daniel Jondle, Richard Miller, James Vesenka, Eric Henderson Jan 1996

Reconstruction Of Ribosomal Subunits And Rdna Chromatin Imaged By Scanning Force Microscopy, Wolfgang Fritzsche, Linda Martin, Drena Dobbs, Daniel Jondle, Richard Miller, James Vesenka, Eric Henderson

Zoology and Genetics Publications

Scanning force microscopy (SFM) reveals surface topography by scanning a sharp tip in close proximity to the sample. Due to tip–sample interaction, artificial broadening of the real surface structure with the tip geometry occurs. One approach for image reconstruction is the use of calibration standards, preferably in the size range of the samples. In the present study, an image reconstruction method based on colloidal gold as a geometric standard was used to reconstruct SFM images of biomolecules. Sample and calibration standard size were in the nanometer range, and the standards were coadsorbed with the specimen. Raw and reconstructed images ...


Ultrastructural Characterization Of Colloidal Metal Films For Bioanalytical Applications By Scanning Force Microscopy, Wolfgang Fritzsche, Konstantin Sokolov, George D. Chumanov, Therese M. Cotton, Eric Henderson Jan 1996

Ultrastructural Characterization Of Colloidal Metal Films For Bioanalytical Applications By Scanning Force Microscopy, Wolfgang Fritzsche, Konstantin Sokolov, George D. Chumanov, Therese M. Cotton, Eric Henderson

Zoology and Genetics Publications

Colloidal metal films (CMFs) are prepared by the attachment of silver, gold, or platinum (or other metal) particles to a glass slide modified by silanization with 3‐mercaptopropyl silane. The covalent attachment of the metal particles occurs through the metal–sulfur bond. In these samples the local electromagnetic field is enhanced near the surface of the CMF due to excitation of plasmon resonances. This phenomenon can be used for a variety of analytical applications. Because the optical properties are strongly dependent on the morphology of the film, its structural characterization becomes of great importance. To further characterize CMFs we have ...