Summary
The anastomosing ER system of epidermal cells of onion bulb scales is composed of three modifications: lamellar and tubular elements, located in the cell periphery, and long tubular stands located deeper in the cytoplasm. Cytoplasmic acidification of epidermal cells by loading with weak organic acids like acetic or propionic acid causes the decay of the lamellar elements and the disappearance of long tubular strands. Organelle movement is also inhibited. The effects depend on the pH of the incubation medium and on the administered acid concentration, and are characterized by a distinct lag phase of about 7 min. The induced ER changes are transient with adaptation starting after about 50min. Buffer components alone have little influence on the cellular ER organization within a pH-range of 4.0–8.0. However, the pH of the medium strongly affects the time course of the effects as well as recovery after omitting the administered acid. Both modulation and recovery occur more rapidly at neutral or slightly alkaline pH. Actin filaments, which play a major role in ER organization and organelle movement, are not affected by cytosolic acidification.
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References
Behnke H-D (1973) Strukturänderung des endoplasmatischen Reticulums und Auftreten von Proteinfilamenten während der Siebröhrendifferenzierung beiSmilax excelsa. Protoplasma 77: 279–289
Busa WB, Nuccitelli R (1984) Metabolic regulation via intracellular pH. Am J Physiol 246: 409–438
Fast H (1989) Untersuchungen zur ER Anordnung in Epidermiszellen der Zwiebelschuppe: Einfluß von schwachen organischen Säuren. Diplom Thesis, Fakultät für Biologie, University of Heidelberg
Felle H (1988 a) Short-term pH-regulation in plants. Physiol Plant 74: 583–591
— (1988 b) Cytoplasmic free calcium inRiccia fluitans L. andZea mays L.: interaction of Ca2+ and pH. Planta 176: 248–255
Frachisse JM, Johannes E, Felle H (1988) The use of weak acids as physiological tools: a study of the effects of fatty acids on intracellular pH and electrical plasmalemma properties ofRiccia fluitans rhizoid cells. Biochim Biophys Acta 938: 199–210
Grinstein S, Goetz JD (1985) Control of free cytoplasmic calcium by intracellular pH in rat lymphocytes. Biochim Biophys Acta 819: 267–270
Guern J, Mathieu Y, Pean M, Pasquier C, Beloeil J-L, Lallemand J-Y (1986) Cytoplasmic pH regulation inAcer pseudoplatanus cells. I. A31PNMR description of acid-load effects. Plant Physiol 82: 840–845
Hager A, Moser I (1985) Acetic acid esters and permeable weak acids induce active proton extrusion and extension growth of coleoptile segments by lowering the cytoplasmic pH. Planta 163: 391–400
Higashi-Fujime S (1988) Actin-induced elongation of fibers composed of cytoplasmic membrane fromNitella. Protoplasma [Suppl] 2: 27–36
Knebel W, Quader H, Wjinaendts-van-Resandt R, Engelhardt H (1989) Applications of confocal laser scanning microscopy in plant biology. Ber Bunsenges Physik Chem 93: 380–386
Kohama K, Shimmen T (1985) Inhibitory Ca2+-control of movement of beads coated withPhysarium myosin along actin cables inChara internodal cells. Protoplasma 129: 88–91
Kohno T, Shimmen T (1988) Accelerated sliding of pollen tube organelles along Characeae actin bundles inhibited by Ca2+. J Cell Biol 106: 1539–1543
Lichtscheidl I, Weiss DG (1988) Visualization of submicroscopic structures in the cytoplasm ofAllium cepa inner epidermal cells by video-enhanced contrast light microscopy. Eur J Cell Biol 46: 376–382
Madshus IH (1988) Regulation of intracellular pH in eukaryotic cells. Biochem J 255: 1–8
Nachmias VT, Yoshida K, Glennon MC (1987) Lowering pH in blood platelets dissociates myosin phosphorylation from shape change and myosin association with the cytoskeleton. J Cell Biol 105: 1761–1769
Quader H (1990) Formation and disintegration of cisternae of the endoplasmic reticulum visualized in live cells by conventional fluorescence and confocal laser scanning microscopy: role of calcium and the cytoskeleton. Protoplasma 155: 166–175
—, Schnepf E (1986) Endoplasmic reticulum and cytoplasmic streaming: fluorescence microscopical observations in adaxial epidermis cells of onion bulb scales. Protoplasma 131: 250–253
—, Hofmann A, Schnepf E (1987) Shape and movement of the endoplasmic reticulum in onion bulb epidermis cells: possible involvement of actin. Eur J Cell Biol 44: 17–26
— — — (1989) Reorganization of the endoplasmic reticulum in epidermal cells of onion bulb scales after cold stress: involvement of cytoskeletal elements. Planta 177: 273–280
Shimmen T, Tazawa M (1985) Mechanism of inhibition of cytoplasmic streaming by myrmicacin (β-hydroxydecanoic acid) inChara andSpirogyra. Protoplasma 127: 93–100
Sonobe S, Shibaoka H (1988) Cortical fine actin filaments in higher plant cells visualized by rhodamine phalloidin after pre-treatment with m-maleimidobenzoyl N-hydroxy succinimide ester. Protoplasma 148: 80–86
Tewinkel M, Kruse I, Quader H, Volkmann D, Sievers A (1989) Visualization of actin filament pattern in plant cells: a comparison of differently modified phallotoxins. Protoplasma 149: 178–182
Toyoshima YY, Toyoshima C, Spudich JA (1989) Bidirectional movement af actin filaments along tracks of myosin heads. Nature 341: 155–156
Traas JA, Doonan JA, Rawlins DJ, Shaw PJ, Watts J, Lloyd CW (1987) An actin network present in the cytoplasm throughout the cell cycle of carrot cells and associates with the dividing nucleus J Cell Biol 105: 387–395
Williamson RE (1986) Organelle movement along actin filaments and microtubules. Plant Physiol 82: 631–634
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Dedicated to the memory of Professor Oswald Kiermayer
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Quader, H., Fast, H. Influence of cytosolic pH changes on the organisation of the endoplasmic reticulum in epidermal cells of onion bulb scales: Acidification by loading with weak organic acids. Protoplasma 157, 216–224 (1990). https://doi.org/10.1007/BF01322654
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DOI: https://doi.org/10.1007/BF01322654