Cell movement within aggregates of the slime mould Dictyostelium discoideum revealed by surface markers

Development ◽  
1965 ◽  
Vol 13 (1) ◽  
pp. 97-117
Author(s):  
B. M. Shaffer
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Movement ◽  
Surface Markers ◽  
Slime Mould ◽  
Culture Plate ◽  
Multicellular Organisms

Earlier workers examined the behaviour of foreign particles placed as markers on aggregates of D. discoideum that were migrating over the surface of the culture plate (Bonner, 1959; Francis, 1959, 1962). Comparable observations, made on aggregates in other conditions and at other stages, have now provided further information about the movement of individual cells within the aggregates. Before reporting them, the course of development must be described in some detail. During aggregation on an ordinary culture plate, D. discoideum amoebae crawl towards centres, in which they pack themselves together, forming rounded aggregates of no fixed shape. Papillae develop on the side of the aggregates away from the agar, and by extension, roughly perpendicular to the substratum, transform them into cylindrical multicellular organisms with tapered tips (Text-fig. 1, A—E). Such an organism, which contains from a dozen to a few hundred thousand cells, has been named a grex (Shaffer, 1962) because ‘aggregation’ is derived from the Latin aggregare, to form a grex.

Electrical properties of the slime mould grex

Development ◽  
1970 ◽  
Vol 23 (2) ◽  
pp. 311-322
Author(s):  
D. R. Garrod ◽  
J. F. Palmer ◽  
L. Wolpert
Keyword(s):  
Electrical Properties ◽  
Dictyostelium Discoideum ◽  
Fruiting Body ◽  
Fruiting Bodies ◽  
Electrophysiological Investigation ◽  
Slime Mould ◽  
Cellular Pattern ◽  
Electric Potentials

An electrophysiological investigation of the migrating grex of the slime mould, Dictyostelium discoideum, has been carried out with two aims in view. It was hoped to obtain information which would be relevant to, first, the formation and regulation of cellular pattern in the grex, and secondly, the problem of grex movement. During migration the grex develops a simple, linear cellular pattern. The cells at the front become the so-called ‘prestalk’ cells which will form the stalk of the fruiting body while those at the back become ‘prespore’ cells and form spores at culmination (Raper, 1940; Bonner, 1944; Bonner & Slifkin, 1949). Moreover, this cellular pattern is capable of polarized regulation. Raper (1940) has shown that portions isolated from the front or back of the grex are capable of forming normally proportioned fruiting bodies. A number of workers have suggested that bio-electric potentials may be involved in regulation of linear cellular pattern.

Characterisation of an epithelium-like layer of cells in the multicellular Dictyostelium discoideum slug

1993 ◽  
Vol 105 (1) ◽  
pp. 243-253
Author(s):  
M. Fuchs ◽  
M.K. Jones ◽  
K.L. Williams
Keyword(s):  
Dictyostelium Discoideum ◽  
Intercellular Space ◽  
Room Temperature ◽  
Cell Layer ◽  
Freeze Substitution ◽  
Specific Cell ◽  
Peripheral Layer ◽  
Apical Membranes ◽  
Multicellular Organisms ◽  
Peripheral Cells

Ultrarapid freezing (RF) followed by freeze-substitution (FS) provide superior preservation of the Dictyostelium discoideum multicellular slug tissue over conventional methods of chemical fixation at room temperature. The peripheral cells of slugs prepared by RF and FS form a tight layer of flattened cells. This cell layer resembles epithelia of other multicellular organisms in that it has close junctional contact between cells associated with the extracellular matrix (ECM, slime sheath). This is the first report that clearly demonstrates the existence of such peripheral cellular specialisation in this otherwise well-studied model system. Junctional contacts between adjacent cells mean that there is no intercellular space evident between apical membranes of apposing cells, and basally the intermembraneous space between peripheral cells is less than 10 nm. By contrast, the intercellular space between internal cells is approximately 10–25 nm. The shape of the peripheral cells varies with their location around the slug. In the posterior prespore zone, the peripheral cells are squamous and exhibit polarity along their antero-posterior axis. In the anterior prestalk zone, peripheral cells are less flattened, project irregular filipodia between internal cells, and are polarised along their apical-basal axis. Colloidal gold immunocytochemistry with the markers MUD1, MUD50 and MUD62 demonstrated that the peripheral layer is formed of prestalk cells in the anterior region and ventrum, and mostly prespore cells along the dorsum. Thus, the peripheral layer, while having specific cell classes in different regions, is not differentiation-specific. Rather, it appears that the structure of these epithelium-like cells is influenced by interaction with molecules of the ECM (sheath).

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 Independent control of locomotion and orientation during Dictyostelium discoideum chemotaxis

1992 ◽  
Vol 102 (4) ◽  
pp. 763-768
Author(s):  
B. Van Duijn ◽  
P.J. Van Haastert
Keyword(s):  
Dictyostelium Discoideum ◽  
High Voltage ◽  
Cell Movement ◽  
Cell Length ◽  
Independent Control ◽  
Motile Cells ◽  
Two Component ◽  
Extracellular Camp

Chemotaxis is cell movement in the direction of a chemical and is composed of two component: movement and directionality. The directionality of eukaryotic chemotaxis is probably derived from orientation: the detection of the spacial gradient of chemoattractant over the cell length. Chemotaxis was investigated in eukaryotic Dictyostelium discoideum cells that were permeabilized by high-voltage discharges. These permeable cells respond chemotactically to extracellular cAMP. However, locomotion is impaired if the Ca2+ concentration is clamped at submicromolar concentrations; interestingly, these non-motile cells still form pseudopodia and elongate in the direction of the cAMP gradient. These results imply that locomotion and orientation during Dictyostelium chemotaxis are independently regulated.

scholarly journals Role of epigenetics in unicellular to multicellular transition in Dictyostelium

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Simon Yuan Wang ◽  
Elizabeth Ann Pollina ◽  
I-Hao Wang ◽  
Lindsay Kristina Pino ◽  
Henry L. Bushnell ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
Orthologous Gene ◽  
Chromatin Accessibility ◽  
Critical Event ◽  
H3k4 Methylation ◽  
Social Amoeba ◽  
The Social ◽  
Conserved Genes ◽  
Multicellular Organisms

Abstract Background The evolution of multicellularity is a critical event that remains incompletely understood. We use the social amoeba, Dictyostelium discoideum, one of the rare organisms that readily transits back and forth between both unicellular and multicellular stages, to examine the role of epigenetics in regulating multicellularity. Results While transitioning to multicellular states, patterns of H3K4 methylation and H3K27 acetylation significantly change. By combining transcriptomics, epigenomics, chromatin accessibility, and orthologous gene analyses with other unicellular and multicellular organisms, we identify 52 conserved genes, which are specifically accessible and expressed during multicellular states. We validated that four of these genes, including the H3K27 deacetylase hdaD, are necessary and that an SMC-like gene, smcl1, is sufficient for multicellularity in Dictyostelium. Conclusions These results highlight the importance of epigenetics in reorganizing chromatin architecture to facilitate multicellularity in Dictyostelium discoideum and raise exciting possibilities about the role of epigenetics in the evolution of multicellularity more broadly.

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