Measurements of intracellular pH and its relevance to cell differentiation in Dictyostelium discoideum

1985 ◽  
Vol 76 (1) ◽  
pp. 235-245 ◽  
Author(s):  
K. Inouye

A method was developed in this study to measure the intracellular pH (pHi) of Dictyostelium discoideum cells with a pH-sensitive fluorescence dye, carboxyfluorescein dibutyrate, and the pHi values of cells on the stalk and spore pathways were compared. The pHi of prestalk cells was lower than that of prespore cells by approximately 0.3 pH unit. In monolayer cultures of sporogenous mutants, which can differentiate into stalk cells and spores without cell contact, the pHi of the amoebae depended on the medium: media in which the majority of cells eventually become stalk cells reduced the pHi while conditions favouring spore formation increased the pHi. Addition of weak acids lowered the pHi. These results are in good accordance with the model presented by Gross and coworkers, which proposes that the choice between alternative pathways of cell differentiation is regulated via pHi and that low pHi favours stalk differentiation whereas high pHi favours spore formation.

Development ◽  
1981 ◽  
Vol 62 (1) ◽  
pp. 369-378
Author(s):  
Robert R. Kay ◽  
David J. Trevan

Amoebae of sporogenous mutants of Dictyostelium discoideum can differentiate into stalk cells and spores in the absence of normal morphogenesis when spread on agar containing cyclic-AMP. The efficiency of differentiation is improved when the amoebae are incubated as submerged monolayers in plastic petri dishes. Under these conditions spore formation is density dependent and hence requires some form of cellular interaction. To determine whether this interaction involves direct cell—cell contact we have made time-lapse films of cells differentiating at intermediate density. These films show that amoebae can develop into spores without making contact with any other cells. In addition, although some cells do divide during incubation, division is not necessary for spore formation. At higher densities small aggregates form which give rise to mixtures of stalk cells and spores. There is no detectable patterning of the two cell types within such aggregates.


Nature ◽  
1983 ◽  
Vol 303 (5914) ◽  
pp. 244-245 ◽  
Author(s):  
J. D. Gross ◽  
J. Bradbury ◽  
R. R. Kay ◽  
M. J. Peacey

Author(s):  
Daiane Carvalho Baía ◽  
Fábio L. Olivares ◽  
Daniel B. Zandonadi ◽  
Cleiton de Paula Soares ◽  
Riccardo Spaccini ◽  
...  

Abstract Background Plants primed by humic acids showed physiological and molecular response against different abiotic stresses without the presence of stressor agents (salinity, drought, heavy metal toxicity). It is plausible that humic acids themselves can act as chemical priming substances in plants. We hypothesized that humic acids can trigger the weak acids stress response in cell plants acidifying the cytosol and thus eliciting the transduction signalling response cascade. Methods The dose–response curves of maize seedlings roots with different concentrations of humic, acetic and salicylic acids determined the most active and inhibitory concentration. These data were further used to evaluate changes on intracellular pH using BCECF-AM probe (2,7-bis(2-carboxyethyl)-5(and 6)-carboxyfluorescein, acetoxymethyl ester) and differential transcription level of genes related to weak stress response in plants by qPCR real time. Results Humic acids like short chain organic acids decrease the intracellular pH showed by the increased fluorescence of BCECF probe. The drop in cytosolic pH promoted by humic acids was not transient. We observed a high level of protein kinases related to cell energy-sensing and transcription factors associated to transduction of stress signalling. Conclusion The humic acids can be considered as a chemical priming agent, since in the appropriate concentration they can induce the typical plant abiotic stress response of weak acids inducing plant acclimation and enhancing the abiotic stress tolerance.


BMC Genomics ◽  
2010 ◽  
Vol 11 (1) ◽  
pp. 264 ◽  
Author(s):  
Frank-Dietrich Müller ◽  
Anke Treuner-Lange ◽  
Johann Heider ◽  
Stuart M Huntley ◽  
Penelope I Higgs

1970 ◽  
Vol 119 (2) ◽  
pp. 171-174 ◽  
Author(s):  
D. J. Watts ◽  
J. M. Ashworth

1. A simple axenic medium suitable for the growth of the myxamoebae of a strain of the cellular slime mould Dictyostelium discoideum is described. 2. Procedures suitable for the growth of this strain in liquid and on solid media are described. 3. Conditions suitable for initiating the cell differentiation of myxamoebae grown axenically are described.


2019 ◽  
Vol 63 (8-9-10) ◽  
pp. 343-357
Author(s):  
Adam Kuspa ◽  
Gad Shaulsky

William Farnsworth Loomis studied the social amoeba Dictyostelium discoideum for more than fifty years as a professor of biology at the University of California, San Diego, USA. This biographical reflection describes Dr. Loomis’ major scientific contributions to the field within a career arc that spanned the early days of molecular biology up to the present day where the acquisition of high-dimensional datasets drive research. Dr. Loomis explored the genetic control of social amoeba development, delineated mechanisms of cell differentiation, and significantly advanced genetic and genomic technology for the field. The details of Dr. Loomis’ multifaceted career are drawn from his published work, from an autobiographical essay that he wrote near the end of his career and from extensive conversations between him and the two authors, many of which took place on the deck of his beachfront home in Del Mar, California.


FEBS Letters ◽  
1993 ◽  
Vol 322 (1) ◽  
pp. 73-75 ◽  
Author(s):  
Yuzuru Kubohara ◽  
Koji Okamoto ◽  
Yoshimasa Tanaka ◽  
Ken-ichi Asahi ◽  
Akira Sakurai ◽  
...  

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