Aggregation during sexual development in Dictyostelium discoideum

1979 ◽  
Vol 25 (12) ◽  
pp. 1416-1426 ◽  
Author(s):  
Danton H. O'Day
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Sexual Development ◽  
Cell Aggregation ◽  
Giant Cells ◽  
Aggregation Process ◽  
Sequence Of Events

A microcinematographic analysis of the behaviour and movements of cells and cell masses in mated cultures (NC4 × V12) of Dictyostelium discoideum indicates that a chemotactic process directs cell aggregation during macrocyst development. Zygote giant cells form before aggregation begins and act as the aggregation centres. Young multicellular macrocyst stages are sources of cyclic AMP, and amoebae from macrocyst cultures orient chemotactically to cyclic AMP. The data, coupled with other characteristics such as pulsatile streaming, suggest that the aggregation process leading to macrocyst development is the same as that occurring during fruit construction. Other aspects of sexual development are also discussed. Based upon these data, we propose a model for the sequence of events leading to macrocyst development in D. discoideum.

Phagocytic specificity during sexual development in Dictyostelium discoideum

1986 ◽  
Vol 32 (2) ◽  
pp. 79-82 ◽  
Author(s):  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Concanavalin A ◽  
Sexual Development ◽  
Wheat Germ ◽  
Giant Cells ◽  
Inhibitory Effect ◽  
Sexual Cycle ◽  
Type I ◽  
Further Development ◽  
Type Receptor

During the sexual cycle of Dictyostelium discoideum, zygote giant cells develop and serve as foci for further development by chemoattracting and cannibalizing hundreds of local amoebae. Previous work has shown that the phagocytic process bears similarities to and differences from asexual endocytosis. In the present study, sexual phagocytosis in D. discoideum was found to be species and developmental stage specific. It was inhibited selectively by glucose and concanavalin A. Although a partial, inhibitory effect of mannose on phagocytosis was not statistically significant, alpha-methylmannosamine, like alpha-methyl-glucose, significantly restored the phagocytic competence of giant cells treated with concanavalin A. Other sugars (N-acetyl glucosamine, N-acetylgalactosamine, and galactose) and lectins (wheat germ agglutinin, Ulex europus type I, and Ricinis communis agglutinin type I) had no significant effect on sexual phagocytosis. Together these data indicate that a glucose-type receptor is involved in selective uptake of D. discoideum amoebae by giant cells.

Action of a slowly hydrolysable cyclic AMP analogue on developing cells of Dictyostelium discoideum

1979 ◽  
Vol 35 (1) ◽  
pp. 321-338
Author(s):  
C. Rossier ◽  
G. Gerisch ◽  
D. Malchow
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Type Strain ◽  
Wild Type Strain ◽  
Agar Plate ◽  
Cell Aggregation ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Camp Analogue ◽  
Order Of Magnitude

Adenosine 3′,5′-cyclic phosphorothioate (cAMP-S) is a cyclic AMP (cAMP) analogue which is only slowly hydrolysed by phosphodiesterases of Dictyostelium discoideum. The affinity of cAMP-S to cAMP receptors at the cell surface is only one order of magnitude lower than that of cAMP. cAMP-S can replace cAMP as a stimulant with respect to all receptor-mediated responses tested, including chemotaxis and the induction of cAMP pulses. cAMP-S does not affect growth of D. discoideum but it blocks cell aggregation at a uniform concentration of 5 × 10(−7) M in agar plate cultures of strain NC-4 as well as its axenically growing derivative, Ax-2. Another wild-type strain of D. discoideum, v-12, is able to aggregate on agar plates supplemented with 1 mM cAMP-S. The development of Polysphondylium pallidum and P. violaceum is also highly cAMP-S resistant. In Ax-2 both differentiation from the growth phase to the aggregation-competent stage and chemotaxis are cAMP-S sensitive, whereas in v-12 only chemotaxis is inhibited. v-12 can still form streams of cohering cells and fruiting bodies when chemotaxis is inhibited by cAMP-S. Whereas cAMP induces differentiation into stalk cells at concentrations of 10(−3) or 10(−4) M, cAMP-S has the same effect in strain v-12 at the much lower concentration of 10(−6) M.

Zygote giant cell differentiation in Dictyostelium discoideum: biochemical markers of specific stages of sexual development

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1200-1208 ◽  
Author(s):  
Darren D. Browning ◽  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Alkaline Phosphatase ◽  
Cell Differentiation ◽  
Giant Cell ◽  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Sexual Development ◽  
Giant Cells ◽  
Second Phase ◽  
Developmental Phase ◽  
Calcium Dependent

Sexual development in Dictyostelium discoideum has many unique features making it an attractive eukaryotic model system for the study of biomembrane fusion and intercellular communication. The work presented here provides primary biochemical evidence for two distinct phases during early sexual development that appear to be defined by calcium-dependent gamete cell fusion. In addition, we introduce a novel procedure for the enrichment of zygote giant cells and use this method to define certain wheat-germ agglutinin binding glycoproteins which are specifically located in zygote giant cells and others which are markers for surrounding amoebae in the second phase of development. In addition, a G protein which is present in high amounts early in development is unique to giant cells in the second phase, suggesting a role in phagocytosis. Finally, alkaline phosphatase activity was found to mark the first phase of sexual development, suggesting a role in cell fusion. This contrasts with the patterns of α-mannosidase and β-glucosidase activity that increase late in the second developmental phase, where they likely function in endocyte digestion during the cytophagic period. The developmental significance of these findings is discussed.Key words: zygote giant cell differentiation, Ca2+, glycoproteins, GTP-binding proteins, alkaline phosphatase, glycosidase, cell fusion.

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.

Nuclear fusion in multinucleated giant cells during the sexual development of Dictyostelium discoideum

1986 ◽  
Vol 118 (1) ◽  
pp. 95-102 ◽  
Author(s):  
H. Okada ◽  
Y. Hirota ◽  
R. Moriyama ◽  
Y. Saga ◽  
K. Yanagisawa
Keyword(s):  
Dictyostelium Discoideum ◽  
Sexual Development ◽  
Nuclear Fusion ◽  
Giant Cells ◽  
Multinucleated Giant Cells

Cell density dependence of the aggregation characteristics of the cellular slime mould Dictyostelium discoideum

1975 ◽  
Vol 19 (1) ◽  
pp. 215-229
Author(s):  
Y. Hashimoto ◽  
M.H. Cohen ◽  
A. Robertson
Keyword(s):  
Density Dependence ◽  
Cell Density ◽  
Dictyostelium Discoideum ◽  
Cell Aggregation ◽  
Signal Propagation ◽  
Quantitative Model ◽  
Aggregation Process ◽  
Body Density ◽  
Cellular Slime ◽  
Formation Efficiency

We have measured fruiting body density and spore formation efficiency in Dictyostelium discoideum as functions of initial cell density. Experiments were performed on agar made up with distilled water and on buffered agar. Minor differences are seen; these are discussed. The functions show 4 regions of density dependence which can be accounted for by changes in aggregation characteristics with density and changes in the efficiency of spore differentiation. The results are discussed in terms of the relaying mechanism for signal propagation controlling cell aggregation. They extend earlier measurements by Bonner & Dodd and by Hohl & Raper, supply data for a quantitative model of the aggregation process, allow estimates of signal range, and show the importance of entrainment between neighbouring centres in defining aggregation territories.

Pronuclear migration, swelling, and fusion during sexual development in Dictyostelium discoideum

1987 ◽  
Vol 33 (12) ◽  
pp. 1046-1049 ◽  
Author(s):  
David R. McConachie ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Mating Type ◽  
Sexual Development ◽  
Significant Relationship ◽  
Giant Cells ◽  
Mixed Mating ◽  
Binucleate Cells ◽  
Ultrastructural Studies

In mixed mating type cultures (strains NC4 × V12) of Dictyostelium discoideum, gametes fuse to produce binucleate cells which differentiate into zygote giant cells. As pronuclei move together their volumes increase dramatically. Measurements of pronuclear volumes revealed that there is a direct, linear, and statistically significant relationship between pronuclear size and proximity. Juxtaposition of the swollen pronuclei is followed by their fusion. Ultrastructural studies indicate that pronuclear fusion involves intact pronuclear envelopes.

The regulation of membrane fusion during sexual development in Dictyostelium discoideum

1989 ◽  
Vol 67 (7) ◽  
pp. 321-326 ◽  
Author(s):  
Danton H. O'Day ◽  
Michael A. Lydan
Keyword(s):  
Cyclic Amp ◽  
Membrane Fusion ◽  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Sexual Development ◽  
Recent Literature ◽  
Developmental Regulation ◽  
Low Molecular Weight ◽  
Sexual Pheromone ◽  
Protein Cell

During the first 24 h of sexual development in Dictyostelium discoideum, three sequential events of membrane fusion occur: gamete fusion, pronuclear fusion, and phagocytosis. The early events of sexual development are regulated by a diverse group of endogenous molecules: (i) a volatile sexual pheromone, (ii) a protein cell fusion inducing factor (CFIF), (iii) a low molecular weight autoinhibitor, (iv) and cyclic AMP. CFIC enhances cell fusion while the autoinhibitor and cyclic AMP both inhibit the event. Both extracellular and intracellular calcium ions are essential for cell and pronuclear fusion. Pharmacological analyses show that the intracellular functions of the divalent cation in these processes are mediated by calmodulin. The autoinhibitor appears to function by inhibiting calmodulin activity. Glucose, mannose, and N-acetylglucosamine containing glycoproteins have been shown to function in both cell fusion and phagocytosis. The interplay between all of these diverse molecules is examined and a review of all of the recent literature is presented.Key words: biomembrane fusion, Dictyostelium, calmodulin, pheromones, cAMP, glycoproteins, developmental regulation, macrocyst, cell fusion, pronuclear fusion, calcium.

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