Sexual pheromone accumulation and response in agar plate and liquid cultures of Dictyostelium discoideum

1982 ◽  
Vol 28 (11) ◽  
pp. 1273-1276 ◽  
Author(s):  
Paul S. Morris ◽  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Liquid Culture ◽  
Agar Plate ◽  
Maximal Activity ◽  
Sexual Pheromone ◽  
Isolation And Characterization ◽  
Sexual Pheromones ◽  
Slime Moulds ◽  
Cellular Slime ◽  
Pheromonal Activity

Sexual development in the mated cultures of Dictyostelium discoideum is initiated by one or more pheromones. In agar plate cultures of NC4, the presence of the pheromone becomes detectable by 22 h and reaches its maximal activity by 24 h. Cells of V12 from plate cultures also reach their maximal responsiveness at 24 h. In liquid culture, the NC4 pheromonal activity is detectable by 10 h and increases to a maximum at 15 h before declining so that by 30 h no activity is detectable. The V12 cells develop the competence to respond to the pheromone by 10 h and increase to a peak responsiveness by 15 h after which they lose the ability to respond. These data support earlier experiments demonstrating that sexual pheromones exist in the cellular slime moulds. The results of the liquid culture experiments in which the pheromonal induction of macrocyst formation reaches levels equivalent to 30% of mated cultures (NC4 × V12) also suggest that this pheromone bioassay system is sensitive enough to permit the isolation and characterization of the sexual pheromones of D. discoideum.

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.

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.

Evidence for the existence of elements of a para-sexual cycle in the cellular slime mould, Dictyostelium discoideum

1969 ◽  
Vol 173 (1033) ◽  
pp. 531-540 ◽  
Keyword(s):  
Dictyostelium Discoideum ◽  
Genetic Recombination ◽  
Sexual Cycle ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Isolation And Characterization ◽  
Cellular Slime

The isolation and characterization of heterozygous diploids of the cellular slime mould Dictyostelium discoideum is described. The diploids are extremely unstable, and haploidization occurs through transient aneuploidy. These genetic and cytological observations suggest that D . discoideum has a para-sexual cycle and previous reports by others of genetic recombination in this organism can be explained on this assumption.

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.

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