Journal Article Intracellular Distribution of Free Amino Acids between the Vacuolar and Extravacuolar Compartments in Internodal Cells of Chara australis Get access Katsuhiro Sakano, Katsuhiro Sakano Department of Botany, Faculty of Science, University of TokyoHongo, Tokyo 113, Japan Search for other works by this author on: Oxford Academic Google Scholar Masashi Tazawa Masashi Tazawa Department of Botany, Faculty of Science, University of TokyoHongo, Tokyo 113, Japan Search for other works by this author on: Oxford Academic Google Scholar Plant and Cell Physiology, Volume 25, Issue 8, December 1984, Pages 1477–1486, https://doi.org/10.1093/oxfordjournals.pcp.a076860 Published: 01 December 1984 Article history Received: 07 June 1984 Accepted: 11 September 1984 Published: 01 December 1984
N-Acetylchitooligosaccharides, fragments of a main backbone polymer of fungal ceil wall, elicit defense responses including phytoalexin production in suspension-cultured rice cells. The purified oligosaccharide triggers rapid, transient membrane depolarization. Ion fluxes induced by the oligosaccharides were analyzed by using ion-selective electrodes. Treatment of the cells with the oligosaccharides induced transient efflux of K+ and influx of H+ immediately after the elicitation. To monitor the pH values of the cytoplasm and the vacuoles noninvasively under a physiological condition, in vivo 31P-nuclear magnetic resonance spectroscopy was applied to the cells to which oxygenated growth medium was perfused continuously. The cytoplasmic pH showed significant transient decrease, correspondingly. Only the N-acetylchitooligosaccharides with a degree of polymerization higher than 5 were active, whereas deacetylated chitosan oligomers caused no effect. Less than 1 nM of N-acetylchitoheptaose was sufficient to induce rapid flux of ions. Such strict structural requirements for the induction of ion fluxes were similar to those of specific binding to the putative plasma membrane receptor as well as a series of signaling events specifically induced by the oligosaccharides, suggesting the involvement of transient changes in cytoplasmic ion concentration in oligosaccharide signaling for defense responses.
Abstract The influence of protein‐synthesis inhibitors on the subcellular distribution of free amino acids was studied in internodal cells of Chara corallina . Use of an intracellular perfusion technique allowed separate measurements of amino acids in the vacuole, in the flowing sol endoplasm and in the gel layer. The sol endoplasm predominantly represents the cytosol, while the gel layer is occupied, for the most part, by chloroplasts. When cells were treated with 0.5 mM chloramphenicol (CRP) in the dark, both the total concentration of amino acids and the subcellular distribution were almost the same as in cells without treatment. In the light, however, the subcellular distribution changed dramatically, although the total concentration of amino acids was unchanged. The vacuolar concentration of amino acids was 3 times greater in CRP‐treated cells than in the control. The concentrations of amino acids in the sol endoplasm and in the gel layer were only half of those in the control. Amino acid permeability of the chloroplast envelope, measured using the perfused internodal cells, slightly increased after the CRP treatment in the light. Time‐dependent changes in concentrations of amino acids in the CRP‐treated cells were also measured in the light. The total concentration of amino acids in the cytoplasm gradually decreased, while that in the vacuole increased commensurately. The concentration and/or subcellular distribution of alanine, glutamine, glutamate and glycine changed dramatically. The concentration of alanine increased considerably both in the vacuole and in the cytoplasm. The cytoplasmic concentration of glutamine increased transiently within 1 −2 h after treatment with CRP. The cytoplasmic concentrations of glutamate and glycine decreased. Although the concentrations of some amino acids changed so markedly both in the vacuole and cytoplasm, only small differences in the activities of glutamic‐pyruvic transaminase, glutamic‐oxaloacetic transaminase and glutamine synthetase were detected between the control and the CRP‐treated cells.
Cytoplasmic acidification during inorganic phosphate (Pi) absorption by Catharanthus roseus cells were studied by means of a fluorescent pH indicator, 2′,7′-bis-(2-carboxyethyl)-5 carboxyfluorescein (acetomethylester) (BCECF), and 31P-nuclear magnetic resonance spectroscopy. Cytoplasmic acidification measured by decrease in the fluorescence intensity started immediately after Pi application. Within a minute or so, a stable state was attained and no further acidification occurred, whereas Pi absorption was still proceeding. As soon as Pi in the medium was exhausted, cytoplasmic pH started to recover. Coincidentally, the medium pH started to recover toward the original acidic pH. The Pi-induced changes in the cytoplasmic pH were confirmed by 31P-nuclear magnetic resonance study. Maximum acidification of the cytoplasm induced by 1.7 millimolar Pi was 0.2 pH units. Vacuolar pH was also affected by Pi. In some experiments, but not all, pH decreased reversibly by 0.2 to 0.3 pH units during Pi absorption. Results suggest that the cytoplasmic pH is regulated by proton pumps in the plasma membrane and in the tonoplast. In addition, other mechanisms that could consume extra protons in the cytoplasm are suggested.
Journal Article Induction of Cytoplasmic Streaming and Movement of Chloroplast Induced by L-Histidine and its Derivatives in Leaves of Egeria densa Get access Masashi Tazawa, Masashi Tazawa 1Department of Biology, Faculty of Science, University of TokyoHongo, Tokyo, 113 Japan Search for other works by this author on: Oxford Academic Google Scholar Sachiko Kurosawa, Sachiko Kurosawa 1Department of Biology, Faculty of Science, University of TokyoHongo, Tokyo, 113 Japan Search for other works by this author on: Oxford Academic Google Scholar Shin-ichi Amino, Shin-ichi Amino 1Department of Biology, Faculty of Science, University of TokyoHongo, Tokyo, 113 Japan Search for other works by this author on: Oxford Academic Google Scholar Yoshito Tominaga, Yoshito Tominaga 2St. Agnes′ Junior CollegeNampeidai, Takatsuki, 569 Japan Search for other works by this author on: Oxford Academic Google Scholar Katsuhiro Sakano, Katsuhiro Sakano 3Department of Applied Physiology, National Institute of Agrobiological ResourcesTsukuba, 305 Japan Search for other works by this author on: Oxford Academic Google Scholar Tomotaka Matsumoto Tomotaka Matsumoto 1Department of Biology, Faculty of Science, University of TokyoHongo, Tokyo, 113 Japan Search for other works by this author on: Oxford Academic Google Scholar Plant and Cell Physiology, Volume 32, Issue 2, March 1991, Pages 253–260, https://doi.org/10.1093/oxfordjournals.pcp.a078071 Published: 01 March 1991 Article history Received: 16 July 1990 Accepted: 20 December 1990 Published: 01 March 1991
