scholarly journals Adenosine 3′:5′-cyclic monophosphate concentrations and phosphodiesterase activities during axenic growth and differentiation of cells of the cellular slime mould Dictyostelium discoideum

1973 ◽  
Vol 134 (1) ◽  
pp. 311-319 ◽  
Author(s):  
A. M. Malkinson ◽  
J. M. Ashworth
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Exponential Phase ◽  
Axenic Medium ◽  
Fruiting Body Formation ◽  
Solid Media ◽  
Cellular Slime ◽  
Second Peak ◽  
Axenic Growth ◽  
Approximate Doubling

During growth of myxamoebae of Dictyostelium discoideum (strain Ax-2) in axenic medium, the myxamoebae secrete cyclic AMP. As the cells leave the exponential phase of growth and enter the stationary phase, there is an approximate doubling of the intracellular cyclic AMP content, but the amount of extracellular cyclic AMP remains proportional, at all times, to the number of myxamoebae present. During development of axenically grown myxamoebae, there is first a rise in the intracellular concentration of cyclic AMP, followed by a rise in the amount of extracellular cyclic AMP, which reaches a peak at the time of aggregation and then declines. There is a second peak in the amount of extracellular cyclic AMP found at the time of fruiting-body formation, but this second peak is not associated with a rise in the intracellular cyclic AMP concentration. Controls thus exist over the synthesis and secretion of cyclic AMP. Evidence is presented for the belief that the activity of the adenylate cyclase enzyme controls the amount of cyclic AMP synthesized rather than the activity or amount of cyclic AMP phosphodiesterase present. Similar changes occur in extracellular cyclic AMP and phosphodiesterase concentrations during incubation of myxamoebae in buffered suspensions to those occuring during the first few hours of development of such cells on solid media, but the timing of these changes is different.

scholarly journals Growth of myxamoebae of the cellular slime mould Dictyostelium discoideum in axenic culture

1970 ◽  
Vol 119 (2) ◽  
pp. 171-174 ◽  
Author(s):  
D. J. Watts ◽  
J. M. Ashworth
Keyword(s):  
Cell Differentiation ◽  
Dictyostelium Discoideum ◽  
Axenic Culture ◽  
Axenic Medium ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Solid Media ◽  
Cellular Slime

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.

scholarly journals Adenosine 3′:5′-cyclic monophosphate-binding protein from the cellular slime mould Dictyostelium discoideum (Short Communication)

1973 ◽  
Vol 133 (3) ◽  
pp. 601-603 ◽  
Author(s):  
Al M. Malkinson ◽  
Janet Kwasniak ◽  
John M. Ashworth
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Short Communication ◽  
Specific Activity ◽  
Binding Protein ◽  
Protein S ◽  
Fold Increase ◽  
Axenic Medium ◽  
Cellular Slime Mould ◽  
Cellular Slime

During the differentiation of myxamoebae of Dictyostelium discoideum strain Ax-2 grown in axenic medium there is a seven- to ten-fold increase in the specific activity of cyclic AMP-binding protein(s). Evidence is presented for the belief that cyclic AMP phosphodiesterase and cyclic AMP-binding protein are distinct molecular species.

Cell sorting out during the differentiation of mixtures of metabolically distinct populations of Dictyostelium discoideum

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 647-661
Author(s):  
C. K. Leach ◽  
J. M. Ashworth ◽  
D. R. Garrod
Keyword(s):  
Life Cycle ◽  
Dictyostelium Discoideum ◽  
Cell Sorting ◽  
Relative Number ◽  
Exponential Phase ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Axenic Medium ◽  
Spore Population ◽  
The Relationship

The behaviour, during the multicellular phase of the life-cycle, of amoebae of Dictyostelium discoideum grown in different media is described. Amoebal populations were marked by growth-temperature-sensitive genetic lesions which do not interfere with developmental phenomena. The fate of cell populations was determined by measuring the relative number of mutant and wild-type cells at various stages in the life-cycle. Cells sort out during development in such a way that they may be ordered in a sequence in which those given early in the following list preferentially appear in the spore population when mixed with those given later in the list: cells grown in axenic medium + 86 mm glucose and harvested when in the exponential phase of growth; cells grown in axenic medium and harvested when in the exponential phase of growth; cells grown on bacteria and harvested when in the exponential phase of growth; cells grown in axenic medium + 86 mM glucose and harvested when in the stationary phase of growth. Chemotactic aggregation and grex migration are not essential for sorting-out to occur but, in the normal life-cycle, the cells of a grex formed from amoebae grown in different media have sorted out anteroposteriorly. The relationship between this sorting out behaviour and the mechanism of pattern formation in fruiting-body morphogenesis is discussed. Differences in density of the amoebae cannot account for the sorting out predispositions we observe.

Inositol 1,4,5-trisphosphate and calcium stimulate actin polymerization in Dictyostelium discoideum

1986 ◽  
Vol 82 (1) ◽  
pp. 41-51
Author(s):  
G.N. Europe-Finner ◽  
P.C. Newell
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Actin Polymerization ◽  
Cell Surface Receptor ◽  
Receptor Stimulation ◽  
Normal Cells ◽  
Cellular Slime Mould ◽  
Inositol 1,4,5 Trisphosphate ◽  
Surface Receptor ◽  
Cellular Slime

The effect of chemoattractants such as cyclic AMP and folate on amoebae of the cellular slime mould Dictyostelium discoideum is to cause a series of rapid intracellular responses. One of the most rapid of these responses is the polymerization of actin associated with the cytoskeleton, an event correlated with pseudopodium formation, which occurs within 3–5 s of chemotactic receptor stimulation. We report that this response can be mimicked by addition of 5 microM-inositol 1,4,5-triphosphate (IP3) or by addition of 100 microM-Ca2+ to saponin-permeabilized amoebae. The data suggest that cytoskeletal actin polymerization occurs in normal cells as a result of IP3 formation in response to cell surface receptor stimulation and the consequent release of Ca2+ from internal stores.

Cyclic AMP oscillations in suspensions of Dictyostelium discoideum

1989 ◽  
Vol 323 (1215) ◽  
pp. 185-224 ◽  
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Time Delays ◽  
Cell Aggregation ◽  
Mixed Cell ◽  
Basic Model ◽  
Signal Relay ◽  
Cellular Slime ◽  
Qualitative Argument ◽  
Adaptation Processes

A model developed previously for signal relay and adaptation in the cellular slime mould Dictyostelium discoideum is shown to account for the observed oscillations of calcium and cyclic AMP in cellular suspensions. A qualitative argument is given which explains how the oscillations arise, and numerical computations show how characteristics such as the period and amplitude of the periodic solutions depend on parameters in the model. Several extensions of the basic model are investigated, including the effect of cell aggregation and the effect of time delays in the activation and adaptation processes. The dynamics of mixed cell populations in which only a small fraction of the cells are capable of autonomous oscillation are also studied.

Periodic stimuli are more successful than randomly spaced ones for inducing development in Dictyostelium discoideum

1988 ◽  
Vol 8 (6) ◽  
pp. 571-577 ◽  
Author(s):  
Vidyanand Nanjundiah
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Vegetative State ◽  
Terminal Differentiation ◽  
Cellular Slime Mold ◽  
Slime Mold Dictyostelium Discoideum ◽  
Cellular Slime ◽  
Per Se ◽  
Stimulation Of

Aggregation in the cellular slime mold Dictyostelium discoideum is due to chemotaxis. The chemoattractant, cyclic AMP, is synthesised and released periodically by the cells. Externally applied periodic pulses of cyclic AMP can also induce differentiation in this organism. The present work examines the role of periodicity per se in cyclic AMP-mediated stimulation of cell differentiation. For this purpose we use Agip53, a Dictyostelium mutant which does not develop beyond the vegetative state but can be made to aggregate and differentiate by reiterated applications of cyclic AMP. Importantly, Agip53 cells do not make or release any cyclic AMP themselves even in response to an increase in extracellular cyclic AMP. A comparison of the relative efficiencies of periodic and aperiodic stimulation shows that whereas the two patterns of stimulation are equally effective in inducing the formation of EDTA-stable cell contacts, periodic stimuli are significantly superior for inducing terminal differentiation. This suggests that there must be molecular pathways which can only function when stimulation occurs at regular intervals.

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