Evidence for chemotaxis during sexual development in Dictyostelium discoideum

1979 ◽  
Vol 25 (4) ◽  
pp. 542-544 ◽  
Author(s):  
Danton H. O'Day ◽  
Antony J. Durston
Keyword(s):  
Dictyostelium Discoideum ◽  
Sexual Development ◽  
Current Knowledge ◽  
Slime Moulds ◽  
Directional Movement ◽  
Oriented Movement ◽  
Cellular Slime ◽  
Cellular Slime Moulds

Amoebae in mated cultures of Dictyostelium discoideum show oriented movement towards young aggregates, suggesting that chemotaxis is involved in macrocyst development. Amoebae also show directional movement towards midendocyte stages, indicating that as the macrocyst develops it continues to be a source of chemoattractant. These data are discussed in terms of our current knowledge about mating in the cellular slime moulds.

The origin of prespore vacuoles in Dictyostelium discoideum cells as analysed by electron-microscopic immunocytochemistry and radioautography

1985 ◽  
Vol 77 (1) ◽  
pp. 93-108 ◽  
Author(s):  
K. Takemoto ◽  
A. Yamamoto ◽  
I. Takeuchi
Keyword(s):  
Golgi Apparatus ◽  
Dictyostelium Discoideum ◽  
Similar Pattern ◽  
Electron Microscopic ◽  
Electron Microscopic Immunocytochemistry ◽  
Slime Moulds ◽  
Cellular Slime ◽  
Specific Antigens ◽  
Electron Microscopic Radioautography ◽  
Cellular Slime Moulds

Prespore vacuoles (PSVs) are specifically formed in prespore cells of the cellular slime moulds and contain spore-specific antigens. We have examined the processes of PSV formation in Dictyostelium discoideum, using both the methods of immunoelectron microscopy with antispore serum and electron-microscopic radioautography with [3H]fucose, which is specifically incorporated into prespore cells. When prespore cells begin to differentiate at the late aggregation stages the Golgi apparatus, consisting of stacked cisternae and numerous vesicles, becomes conspicuous. Vesicles and flat sacs containing fibrous and membranous materials, respectively, are derived from Golgi cisternae. Spore antigens are found in these structures as well as in immature and mature PSVs. Fucose is incorporated into the same structures. When prespore differentiation is completed, the Golgi cisternae almost disappear and both antigens and fucose are localized in mature PSVs. The Golgi apparatus is scarcely observable in prestalk cells. Moreover, a similar pattern of changes in the Golgi apparatus and related structures occurs during the re-differentiation of prespore cells within prestalk isolates. It is concluded from these findings that PSVs are derived from the Golgi apparatus, the development of which is closely related to the differentiation of prespore cells.

Mutual cohesion and cell sorting-out among four species of cellular slime moulds

1978 ◽  
Vol 32 (1) ◽  
pp. 377-387
Author(s):  
A. Nicol ◽  
D.R. Garrod
Keyword(s):  
Dictyostelium Discoideum ◽  
Binary Mixtures ◽  
Cell Sorting ◽  
The Other ◽  
Cell Aggregates ◽  
Slime Moulds ◽  
Biochemical Studies ◽  
Cellular Slime ◽  
I Cells ◽  
Cellular Slime Moulds

Interspecific cell cohesion among 4 species of cellular slime moulds, Dictyostelium discoideum, D. mucoroides, D. purpureum and Polysphondylium violaceum has been studied. Binary mixtures of aggregation-stage cells of the 4 species were shaken in suspension, one species of each pair being labelled with [3H]thymidine. Cell aggregates were sampled at intervals over 24 h and their composition examined by autoradiography. The following results were obtained: (i) Cells of each species were capable of cohesion with those of the other 3 species. (ii) In general cells of both species in any mixture were present in aggregates after 1 h, but were not localized according to species. (iii) Within 8-h aggregates cells of different species were regionally localized, i.e. sorting-out appeared to have taken place. (iv) 24-h aggregates were more varied: in mixtures of Dictyostelium species, the different species were localized within the aggregates; in mixtures of Dictyostelium species with Polsphondylium, there was a tendency for cells of the different species to become segregated into completely separate aggregates. The significance of these results in relation to both previous descriptive work and recent biochemical studies on the mechanism of slime mould cell cohesion is discussed.

Differentiation for aggregation in the cellular slime moulds: the emergence of autonomously signalling cells in Dictyostelium discoideum

1976 ◽  
Vol 21 (2) ◽  
pp. 243-259 ◽  
Author(s):  
R.K. Raman ◽  
Y. Hashimoto ◽  
M.H. Cohen ◽  
A. Robertson
Keyword(s):  
Population Size ◽  
Dictyostelium Discoideum ◽  
Exponential Growth ◽  
Small Populations ◽  
Slime Moulds ◽  
Cellular Slime ◽  
Cellular Slime Moulds

The results of experiments on small populations of Dictyostelium discoideum, directed towards the measurement of the development in time of the competence of the cells to signal autonomously, are reported. This competence is quantified by X3, the intrinsic probability that a given cell may turn autonomous. The data show an early exponential growth in time of X3, followed by saturation. The saturation value depends on the population size suggesting that the differentiation is a co-operative phenomenon. The differentiation of autonomous cells starts roughly 7 h after the removal of food and saturates within 21 h.

Acrasin, the Chemotactic Agent in Cellular Slime Moulds

1956 ◽  
Vol 33 (4) ◽  
pp. 645-657
Author(s):  
B. M. SHAFFER
Keyword(s):  
Room Temperature ◽  
Dialysis Membrane ◽  
Relay System ◽  
Highly Active ◽  
Slime Moulds ◽  
Cellular Slime ◽  
Set Up ◽  
Cellular Slime Moulds ◽  
Extracellular Slime ◽  
Do So

1. A study has been made of acrasin, the agent inducing chemotaxis in the amoebae of cellular slime moulds. 2. A method has been developed for subjecting sensitive amoebae to a fluctuating gradient set up by an artificial source that can be renewed at intervals of as little as a few seconds with fresh test solution. 3. Amoebae orient to a gradient maintained with the cell-free liquid freshly obtained from the immediate surroundings of a natural source. 4. Acrasin solution as secreted loses its activity very rapidly at room temperature. 5. A highly active stable solid is obtained by drying methanolic culture extracts; it resists boiling and exposure to acids and alkalis. Its solubility decreases rapidly in passing up the alcohol series. 6. The original instability has been shown to be due to the presence of another extracellular slime-mould product, possibly an enzyme; it, unlike acrasin, cannot pass rapidly across a dialysis membrane, is heat labile, and can be precipitated by ammonium sulphate. 7. The advantages of the organism's itself inactivating acrasin are considered. 8. Some of the advantages of a source's releasing acrasin in pulses are discussed; but it is not essential for orientation for it to do so. 9. Sensitive amoebae not only are oriented by an acrasin solution but are caused to secrete acrasin: this is the basis of a chemotactic relay system.

Vertebrates as vectors of cellular slime moulds in temperate forests

1992 ◽  
Vol 96 (8) ◽  
pp. 670-672 ◽  
Author(s):  
Steven L. Stephenson ◽  
John C. Landolt
Keyword(s):  
Temperate Forests ◽  
Slime Moulds ◽  
Cellular Slime ◽  
Cellular Slime Moulds

Implications of enzyme kinetics

2003 ◽  
Vol 31 (3) ◽  
pp. 719-722 ◽  
Author(s):  
A.G. McDonald
Keyword(s):  
Calcium Concentration ◽  
Calcium Oscillations ◽  
Rate Laws ◽  
Sustained Oscillations ◽  
Slime Moulds ◽  
Cellular Slime ◽  
The Many ◽  
Oxidase Reaction ◽  
Signalling Systems ◽  
Cellular Slime Moulds

Of the many examples of oscillatory kinetic behaviour known, several are briefly reviewed, including those of glycolysis, the peroxidase–oxidase reaction and oscillations in cellular calcium concentration. It is shown that simple mathematical models employing allosteric rate laws are sufficient to explain the instability of the steady state and the appearance of sustained oscillations. The cAMP-signalling systems of cellular slime moulds and the dynamics of intracellular calcium oscillations illustrate the importance of such oscillophores to inter- and intra-cellular communication and differentiation.

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