Summary
Changes in intracellular pH (pHi) have been examined during zoosporogenesis inPhytophthora cinnamomi in order to elucidate the molecular mechanisms that bring about initiation of the orderly cleavage of the sporangium. By microinjecting a dextranconjugated pH-sensitive fluorescent indicator, 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF dextran), and using fluorescence ratio image analysis, the pHi of a sporangium was monitored throughout the process of zoosporogenesis. The pHi of mature sporangia was found to remain constant at pH 6.84 ± 0.05 (mean ± SE, n=6) at room temperature (24 °C), but increased to 7.04 ± 0.04 (p < 0.001) during a 20 min cold treatment at 19 °C. As the process of zoosporogenesis proceeded, the increased level of pHi was maintained for 30–40 min after initiation of the cold shock. Zoosporogenesis was blocked when the pHi of the sporangium was held constant by microinjecting with 10 mM HEPES buffer (pH 7.0) before cytoplasmic cleavage was induced by a cold shock. In contrast, no inhibitory effect was observed when sporangia were microinjected with HEPES buffer after the cold shock. These results indicate that initiation of cytoplasmic cleavage requires a rise in pHi.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Austin C, Wray S (1994) A quantitative study of the relation between intracellular pH and force in rat mesenteric vascular smooth muscle. Pflügers Arch 427: 270–276
Baltz JM (1993) Intracellular pH regulation in the early embryo. Bio-Essays 15: 523–530
Blatt MR, Armstrong F (1993) K+ channels of stomatal guard cells: abscisic-acid-evoked control of the outward rectifier mediated by cytoplasmic pH. Planta 191: 330–341
Briskin DP, Hanson JB (1992) How does the plant plasma membrane H+-ATPase pump protons? J Exp Bot 43: 269–289
Busa WB (1986) Mechanisms and consequences of pH-mediated cell regulation. Annu Rev Physiol 48: 389–402
—, Nuccitelli R (1984) Metabolic regulation via intracellular pH. Am J Physiol 246: R409-R438
Davies JM, Brownlee C, Jennings DH (1990) Measurement of intracellular pH in fungal hyphae using BCECF and digital imaging microscopy. Evidence for a primary proton pump in the plasmalemma of a marine fungus. J Cell Sci 96: 731–736
Gould MC, Stephano JL (1993) Nuclear and cytoplasmic pH increase at fertilization inUrechis caupo. Dev Biol 159: 608–617
Hardham AR, Suzaki E (1986) Encystment of the fungus,Phytophthora cinnamomi, is induced by specific lectin and monoclonal antibody binding to the cell surface. Protoplasma 133: 165–173
—, Gubler F, Duniec J, Elliot J (1991) A review of methods for the production and use of monoclonal antibodies to study zoosporic plant pathogens. J Microsc 162: 305–318
Harold FM, Kropf DL, Caldwell JH (1985) Why do fungi drive electric currents through themselves? Exp Mycol 9: 183–186
Harold RL, Harold FM (1992) Configuration of actin microfilaments during sporangium development inAchlya bisexualis: comparison of two staining protocols. Protoplasma 171: 110–116
Haworth RS, Fliegel L (1993) Intracellular pH inSchizosaccharo-mycespombe — comparison withSaccharomyces cerevisiae. Mol Cell Biochem 124: 131–140
Heath IB, Harold RL (1992) Actin has multiple roles in the formation and architecture of zoospores of the oomycetes,Saprolegnia ferax andAchlya bisexualis. J Cell Sci 102: 611–627
Hepler PK, Cleary AL, Gunning BES, Wadsworth P, Wasteneys GO, Zhang DH (1993) Cytoskeletal dynamics in living plant cells. Cell Biol Int 17: 127–142
Ho AK, Chik CL (1994) Acute elevation of intracellular pH translocates protein kinase C activities in rat pinealocytes. Biochem Biophys Res Commun 200: 569–576
Hyde GJ, Hardham AR (1993) Microtubules regulate the generation of polarity in zoospores ofPhytophthora cinnamomi. Eur J Cell Biol 62: 75–85
—, Lancelle S, Hepler PK, Hardham AR (1991) Freeze substitution reveals a new model for sporangial cleavage inPhytophthora, a result with implications for cytokinesis in other eukaryotes. J Cell Sci 100: 735–746
Iser JR, Griffith JM, Balson A, Grant BR (1989) Accelerated ion fluxes during differentiation in zoospores ofPhytophthora palmivora. Cell Diff Dev 26: 29–38
Isfort RJ, Cody DB, Asquith TN, Ridder GM, Stuard SB, Leboeuf RA (1993) Induction of protein phosphorylation, protein synthesis, immediate-early-gene expression and cellular proliferation by intracellular pH modulation. Implications for the role of hydrogen ions in signal transduction. Eur J Biochem 213: 349–357
Jackson SL (1995) Microinjection of fungal cells: a powerful experimental technique. Can J Bot 73: S435–443
James-Kracke MR (1992) Quick and accurate method to convert BCECF fluorescence to pHi: calibration in three different types of cell preparations. J Cell Physiol 151: 596–603
Johansson F, Sommarin M, Larsson C (1993) Fusicoccin activates the plasma membrane H+-ATPase by a mechanism involving the C-terminal inhibitory domain. Plant Cell 5: 321–327
Lestan D, Lestan M, Perdih A (1994) Physiological aspects of biosynthesis of lignin peroxidases byPhanerochaete chiysosporium. Appl Environ Microbiol 60: 606–612
Opritov VA, Pyatygin SS, Krauz VO (1993) Role of electrical activity in cooling-induced development of adaptation syndrome in higher plant cells. Russ J Plant Physiol 40: 619–626
— — —, Khudyakov VA, Abramova NN (1994) Activation of the electrogenic plasmalemma H+-pump in the adaptation of higher plants to moderate low-temperature stress. Russ J Plant Physiol 41: 428–432
Roos A, Boron WF (1981) Intracellular pH. Physiol Rev 61: 296–434
Rink TJ, Tsien RY, Pozzan T (1982) Cytoplasmic pH and free Mg2+ in lymphocytes. J Cell Biol 95: 189–196
Sanders D, Slayman CL (1982) Control of intracellular pH. Predominant role of oxidative metabolism, not proton transport, in the eukaryotic microorganismNeurospora. J Gen Physiol 80: 377–402
— —, Pall ML (1983) Stoichiometry of H+/amino acid cotransport inNeurospora crassa revealed by current-voltage analysis. Biochim Biophys Acta 735: 67–76
Silver RA, Whitaker M, Bolsover SR (1992) Intracellular ion imaging using fluorescent dyes: artefacts and limits to resolution. Pflügers Arch 420: 595–602
Snowdowne KW, Way B, Thomas G, Chen HY, Cashman JR (1992) pHi controls cytoplasmic calcium in rat parotid cells. Biochim Biophys Acta 1108: 145–152
Whitaker MJ, Steinhardt RA (1985) Ionic signalling in the sea urchin egg at fertilization. In: Metz CB, Monroy A (eds) Biology of fertilization, vol 3. Academic Press, New York, pp 168–221
Yoshida S (1994) Low temperature induced cytoplasmic acidosis in cultured mung bean (Vigna radiata Wilczek) cells. Plant Physiol 104: 1131–1138
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Suzaki, E., Suzaki, T., Jackson, S.L. et al. Changes in intracellular pH during zoosporogenesis inPhytophthora cinnamomi . Protoplasma 191, 79–83 (1996). https://doi.org/10.1007/BF01280827
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01280827