The cell cycle and sorting behaviour in Dictyostelium discoideum

1984 ◽  
Vol 66 (1) ◽  
pp. 195-204 ◽  
Author(s):  
S.A. McDonald ◽  
A.J. Durston
Keyword(s):  
Cell Cycle ◽  
Dictyostelium Discoideum ◽  
Cell Sorting ◽  
S Phase ◽  
Cellular Slime Mould ◽  
Cell Counts ◽  
Published Evidence ◽  
Cellular Slime ◽  
High Degree

Synchronized cells of the cellular slime mould Dictyostelium discoideum were prepared by mitotic wash-off. Cell counts and DNA synthesis measurements indicated a high degree of synchrony. Cells from each phase of the cell cycle were fluorescently labelled and mixed with unlabelled asynchronous cells. Cells that were in S-phase and very early G2 at the onset of starvation demonstrated a strong tendency to sort to the tip of the subsequent slugs. With reference to these results and published evidence, we discuss the possible role of cell-cycle-related adhesion differences in cell sorting.

The role of phosphodiesterase in aggregation of Dictyostelium discoideum

1978 ◽  
Vol 31 (1) ◽  
pp. 233-243
Author(s):  
M. Darmon ◽  
J. Barra ◽  
P. Brachet
Keyword(s):  
Dictyostelium Discoideum ◽  
Direct Contact ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Extracellular Medium ◽  
Camp Phosphodiesterase ◽  
Cellular Slime Mould ◽  
Cellular Slime ◽  
Mutant Cells

The role of cAMP phosphodiesterase in the cAMP-mediated aggregation of the cellular slime mould Dictyostelium discoideum was investigated with a morphogenetic mutant defective in phosphodiesterase production. Mutant cells become capable of aggregating normally when incubated in the presence of exogenous phosphodiesterase isolated from Idictyostelium or rat brain. Direct contact between enzyme and the cell membrane is not required for this phenotypic suppression. The aggregateless character of this strain presumably results from an over-accumulation of cAMP in the extracellular medium since aggregation can be induced in the absence of added phosphodiesterase under conditions facilitating diffusion of the nucleotide. This suggests that phosphodiesterase is not involved in the generation or recognition of cAMP signals, but that the enzyme is essential in the control of the cAMP signal-to-noise ratio.

Motive force of the migrating pseudoplasmodium of the cellular slime mould Dictyostelium discoideum

1980 ◽  
Vol 41 (1) ◽  
pp. 53-64
Author(s):  
K. Inouye ◽  
I. Takeuchi
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Sorting ◽  
Unit Volume ◽  
Cell Types ◽  
Motive Force ◽  
Cell Type ◽  
Weighted Mean ◽  
Cellular Slime Mould ◽  
Cellular Slime ◽  
Double Chamber

Motive forces of migrating pseudoplasmodia (slugs) of Dictyostelium discoideum were determined by application of a double-chamber method. The motive force of a whole slug was proportional to its volume, the value per unit volume being 5.85 × 10(−6) dyne/cm3 (58.5 N cm-3). The motive force was independent of temperature (13.5–26 degrees C) and decreased during prolonged migration. Motive force per unit volume of an anterior isolate of a slug was much larger than that of a posterior isolate, their weighted mean being approximately equal to that of a whole slug. These results agree well with the predictions previously made using a model based on analyses of migrating velocities of slugs. The motive force per unit volume of either isolate was soon regulated to reach the normal value of an intact slug after several hours of isolation, concurrently with conversion of cell types between prestalk and prespore cells. The possibility that motive force of each cell is determined by its cell type is discussed in relation to cell sorting.

scholarly journals Posttranslational Phosphorylation and Ubiquitination of the Saccharomyces cerevisiae Poly(A) Polymerase at the S/G2 Stage of the Cell Cycle

2000 ◽  
Vol 20 (8) ◽  
pp. 2794-2802 ◽  
Author(s):  
Neptune Mizrahi ◽  
Claire Moore
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Sorting ◽  
S Phase ◽  
Phase Arrest ◽  
Phosphatase Treatment ◽  
M Phase ◽  
64 Kda Protein ◽  
Mitotic Phosphorylation ◽  
Cycle Regulation

ABSTRACT The poly(A) polymerase of the budding yeast Saccharomyces cerevisiae (Pap1) is a 64-kDa protein essential for the maturation of mRNA. We have found that a modified Pap1 of 90 kDa transiently appears in cells after release from α-factor-induced G1 arrest or from a hydroxyurea-induced S-phase arrest. While a small amount of modification occurs in hydroxyurea-arrested cells, fluorescence-activated cell sorting analysis and microscopic examination of bud formation indicate that the majority of modified enzyme is found at late S/G2 and disappears by the time cells have reached M phase. The reduction of the 90-kDa product upon phosphatase treatment indicates that the altered mobility is due to phosphorylation. A preparation containing primarily the phosphorylated Pap1 has no poly(A) addition activity, but this activity is restored by phosphatase treatment. A portion of Pap1 is also polyubiquitinated concurrent with phosphorylation. However, the bulk of the 64-kDa Pap1 is a stable protein with a half-life of 14 h. The timing, nature, and extent of Pap1 modification in comparison to the mitotic phosphorylation of mammalian poly(A) polymerase suggest an intriguing difference in the cell cycle regulation of this enzyme in yeast and mammalian systems.

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 Glycoproteins that exhibit extensive size polymorphisms in Dictyostelium discoideum.

Genetics ◽  
1989 ◽  
Vol 122 (1) ◽  
pp. 59-64 ◽  
Author(s):  
E Smith ◽  
A A Gooley ◽  
G C Hudson ◽  
K L Williams
Keyword(s):  
Linkage Group ◽  
Dictyostelium Discoideum ◽  
Allelic Variation ◽  
Surface Glycoprotein ◽  
Developmentally Regulated ◽  
Electrophoretic Variants ◽  
Cellular Slime Mould ◽  
Repeat Units ◽  
Group I ◽  
Cellular Slime

Abstract Electrophoretic variants which arise from amino acid substitutions, leading to charge differences between proteins are ubiquitous and have been used extensively for genetic analysis. Less well documented are polymorphisms in the size of proteins. Here we report that a group of glycoproteins, which share a common carbohydrate epitope, vary in size in different isolates of the cellular slime mould, Dictyostelium discoideum. One of these proteins, PsA, a developmentally regulated prespore-specific surface glycoprotein, has previously been shown to exist in three size forms due to allelic variation at the pspA locus on linkage group I. In this report, a second glycoprotein, PsB, which is also prespore specific but found inside prespore cells, is studied. PsB maps to linkage group II and exhibits at least four different sizes in the isolates examined. We propose that the size polymorphisms are the product of allelic variation at the pspB locus, due to differences in the number of repeat units.

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