Experimentally induced aberrations in the pattern of differentiation in the cellular slime mould Dictyostelium discoideum

Development ◽  
1974 ◽  
Vol 31 (2) ◽  
pp. 435-451
Author(s):  
Paul Farnsworth
Keyword(s):  
Cell Mass ◽  
Cell Types ◽  
Fruiting Bodies ◽  
Normal Pattern ◽  
Cellular Slime Mould ◽  
Slime Moulds ◽  
Aqueous Environments ◽  
A Cell ◽  
Cellular Slime ◽  
Special Case

This paper describes a set of perturbatory experiments designed to elucidate aspects of the mechanism by which the normal pattern of differentiation is specified. Experiments are described which investigate the alterations in development seen in aqueous environments, with changes in humidity and with the introduction of permeable and impermeable barriers. The following results are reported: (i) The pattern of differentiation and the various morphologies of fruiting bodies formed when cell masses are placed in or on drops of buffer. (ii) The alteration of the ratio of cell types formed in aqueous environments in the presence of urethane, mercaptoethanol or EDTA. (iii) Humidity dependent changes in polarity and the increase of the number of developmental axes with humidity. (iv) The formation of two developmental axes in cell masses bisected by impermeable barriers and a special case of bisection which induces the whole cell mass to form spores. (v) The induction of all of any of a cell mass enclosed in a ‘cellulose’ tube to form a tissue ultrastructurally demonstrable to be the same as that of stalk. These results are discussed in relationship to the work of other authors and the problem of the specification of the patterns of differentiation in the slime moulds. The results are presented in support of a model proposed previously by the author in which the pattern of the two differentiated cell types is inherent in the morphogenetic changes of culmination, and essential requirements of such a model are correlated with these observations.

Integration in Aggregating Cellular Slime Moulds

1958 ◽  
Vol s3-99 (45) ◽  
pp. 103-121
Author(s):  
B. M. SHAFFER
Keyword(s):  
Cell Movement ◽  
Fixed Time ◽  
Cellular Slime Mould ◽  
Slime Moulds ◽  
Cell Velocity ◽  
A Cell ◽  
Considerable Length ◽  
Cellular Slime ◽  
Peripheral Cells ◽  
Cellular Slime Moulds

1. Cellular-slime-mould amoebae that adhere poorly to one another on contact and effectively do not secrete the chemotactic agent acrasin may become strongly adhesive and start to secrete it. This change, which is particularly important for their aggregation, has been called integration, and the reverse change, disintegration. 2. In Polysphondylium violaceum a cell may receive the integrative stimulus at some distance from the acrasin source that attracts it, but usually it does not change till it has moved close to it or actually reached it; so either an aggregation is simply a heap without any tributary cell-streams, or virtually continuous streams are slowly built out from the centre. 3. In Dictyostelium discoideum the spread of integration, in comparison with cell velocity, may be so rapid that the inflowing streams very soon reach their ultimate extent, though if the population density is not too high their cells only slowly establish contact with one another. 4. As the peripheral cells become integrated, they ‘relay’ the centre's influence. Whether the streams are uninterrupted or ‘stippled’, there need be no continuous and finely graded centrifugal decrement in acrasin secretion: orderly aggregation is ensured by the sequence in which secretion is induced, which results in the centrifugal propagation of one or more comparatively narrow zones in which the gradient is adequate for orientation. 5. A spontaneous or an experimentally produced decrease in the strength of the integrative stimulus, or adaptation to the stimulus, or both, may induce some integrated cells to revert to the unintegrated state. 6. The spread of disintegration, too, in comparison with cell velocity, tends to be more rapid in D. discoideum than in P. violaceum: in the former species all the cells in a considerable length of stream may begin to separate at almost the same time; in the latter they may detach themselves in succession. 7. As disintegration may affect any part of an aggregation, various patterns result therefrom. If it slowly spreads from the centre of a P. violaceum aggregation while the streams are still growing at their outer ends, a ‘fairy ring’ is formed, in which cell movement remains polar. 8. Populations of a D. mucoroides strain, if not too sparse, aggregate at a comparatively fixed time after consuming the available food; but those of D. discoideum at widely different densities and degrees of starvation produce synchronous outbursts of aggregation when transferred from darkness to light. 9. The development and distinctive properties of the initiators of aggregation centres are considered. These cells can release acrasin into the medium without there being any there already or without there being sufficient to induce the remaining cells to secrete. 10. Much evidence is against aggregation being basically a sexual phenomenon.

scholarly journals An Anucleolate Mutant of the Cellular Slime Mould Dictyostelium discoideum

Microbiology ◽  
2000 ◽  
Vol 81 (2) ◽  
pp. 491-499 ◽  
Author(s):  
S. ISHIDA ◽  
Y. MAEDA ◽  
I. TAKEUCHI
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Mass ◽  
Stalk Cell ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Growth Difference ◽  
A Cell ◽  
Cellular Slime ◽  
Tetrazolium Reduction ◽  
Spore Cell

Summary: An anucleolate mutant (AN) was isolated from the cellular slime mould, Dictyostelium discoideum. The AN developed normally until the beginning of culmination, when development stopped and no differentiation of the spore or stalk cell occurred. The AN had nucleoli at the vegetative stage, but lost them after formation of a cell mass, in contrast to the wild type (WT) which possessed them throughout development. AN cells disaggregated from a slug, reconstructed nucleoli and resumed vegetative growth. Difference in tetrazolium reduction between the prestalk cell and the pre-spore cell, as observed in the WT, was not detected in the AN, although vacuoles specific to the pre-spore cell were formed. When the WT and AN cells were mixed, they aggregated together, but no interaction in cell differentiation was observed. The roles of nucleoli in the development of this organism are discussed.

Proportionality in the pattern of differentiation of the cellular slime mould Dictyostelium discoideum and the time of its determination

Development ◽  
1975 ◽  
Vol 33 (4) ◽  
pp. 869-877
Author(s):  
Paul A. Farnsworth
Keyword(s):  
Cell Differentiation ◽  
Incubation Temperature ◽  
Quantitative Measure ◽  
Temperature Shift ◽  
Fruiting Bodies ◽  
Developmental Sequence ◽  
Cellular Slime Mould ◽  
Cellular Slime ◽  
And Migration

A quantitative measure of the proportionality of the pattern of cell differentiation is obtained by separating populations of fruiting bodies into stalks and spores and determining the ratio of their dry weights. The effect of incubation temperature on the proportion of a population which becomes stalk cells is determined. The time of determination of this proportion is then indicated by the time in the developmental sequence at which a temperature shift fails to alter it. The results show that the temperatures of growth, aggregation and migration have no effect on the pattern of differentiation and that temperature alterations during early culmination alter the pattern of differentiation. This result demonstrates that the pattern of differentiation is not determined during the migrating slug stage, and it is suggested that the axial inhomogeneities seen in the slug are not directly related to the terminal pattern of differentiation of the fruiting body as has been previously suggested.

Inhibition of intercellular adhesion in a cellular slime mould by univalent antibody against a cell-surface lectin

Nature ◽  
1976 ◽  
Vol 263 (5576) ◽  
pp. 425-427 ◽  
Author(s):  
STEVEN D. ROSEN ◽  
PATRICIA L. HAYWOOD ◽  
SAMUEL H. BARONDES
Keyword(s):  
Cell Surface ◽  
Intercellular Adhesion ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
A Cell ◽  
Cellular Slime

scholarly journals Clonal culturing of human embryonic stem cells on laminin-521/E-cadherin matrix in defined and xeno-free environment

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Sergey Rodin ◽  
Liselotte Antonsson ◽  
Colin Niaudet ◽  
Oscar E. Simonson ◽  
Elina Salmela ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Cell Types ◽  
A Cell ◽  
Hes Cells ◽  
Free Environment ◽  
Different Cell Types ◽  
E Cadherin

Abstract Lack of robust methods for establishment and expansion of pluripotent human embryonic stem (hES) cells still hampers development of cell therapy. Laminins (LN) are a family of highly cell-type specific basement membrane proteins important for cell adhesion, differentiation, migration and phenotype stability. Here we produce and isolate a human recombinant LN-521 isoform and develop a cell culture matrix containing LN-521 and E-cadherin, which both localize to stem cell niches in vivo. This matrix allows clonal derivation, clonal survival and long-term self-renewal of hES cells under completely chemically defined and xeno-free conditions without ROCK inhibitors. Neither LN-521 nor E-cadherin alone enable clonal survival of hES cells. The LN-521/E-cadherin matrix allows hES cell line derivation from blastocyst inner cell mass and single blastomere cells without a need to destroy the embryo. This method can facilitate the generation of hES cell lines for development of different cell types for regenerative medicine purposes.

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.

The effect of chymotrypsin on the development of Dictyostelium discoideum

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 189-201
Author(s):  
David C. Kilpatrick ◽  
Jerzy A. Schmidt ◽  
John L. Stirling ◽  
John Pacy ◽  
Gareth E. Jones
Keyword(s):  
Electron Microscopy ◽  
Dictyostelium Discoideum ◽  
Normal Development ◽  
Fruiting Bodies ◽  
Con A ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Spore Walls ◽  
Cellular Slime ◽  
Vacuolated Cells

Development of the cellular slime mould Dictyostelium discoideum strain NC4, in the presence of α-chymotrypsin (3 mg/ml) is reversibly arrested at the tight aggregate stage (10/12 h). Pronase has a similar effect, but trypsin only retards normal development by about five hours. Normally developing cells are susceptible to α-chymotrypsin if they are transferred into its presence at any time up to the tight aggregate stage (10–12 h). Transfer after this stage does not affect the appearance of fruiting body structures in the normal time (24 h). Electron microscopy showed the ultrastructure of α-chymotrypsin-blocked aggregates after starvation for 24 h to be consistent with a block at 10–12 h of normal development. Poorly developed prespore vacuoles, having thin incomplete walls and a paucity of electrondense material, are present in some cells. No angular vacuolated cells characteristic of stalk cells are visible. Fruiting bodies formed in the presence of a α-chymotrypsin, either as minority structures when the enzyme is added before 10–12 h of normal development, or as the majority structures on later enzyme addition, were found to be abnormal. Normal stalks were formed but the spores were immature. Prespore vacuoles were present, though disrupted, and the cells were not encapsulated by spore walls. The electronegativity of intact slime mould amoebae was significantly reduced, and material containing L-[6-3H]-fucose and [l-14C]leucine was removed from the cell surface on α-chymotrypsin treatment. Few plasma membrane proteins were affected, however, and staining of polyacrylamide gels for glycopeptides using Con A-peroxide binding also showed little change.

The presence and location of sporopollenin in fruiting bodies of the cellular slime moulds

1984 ◽  
Vol 66 (1) ◽  
pp. 297-308
Author(s):  
Y. Maeda
Keyword(s):  
Cell Membrane ◽  
Biological Significance ◽  
Spore Wall ◽  
Fruiting Bodies ◽  
Fruiting Body Formation ◽  
Body Formation ◽  
Slime Moulds ◽  
Inner Surface ◽  
Cellular Slime ◽  
Cellular Slime Moulds

The presence of an acetolysis-resistant polymer (sporopollenin) in the cellular slime moulds is demonstrated. This polymer is located on the stalk sheath of fruiting bodies as a bundle of fine fibrils (4-5 nm diameter). The location and structure of sporopollenin in spores are shown to vary considerably, depending upon the species. In Polysphondylium violaceum spores, sporopollenin is composed of fine spicules (4-5 nm in diameter, 25–50 nm long) that cover both the outermost layer of spore wall and the inner surface of the cell membrane. The sporopollenin of Dictyostelium discoideum spores is located preferentially close to the inner surface of the cell membrane, forming a mass of electron-opaque fine granules (4-5 nm in diameter). D. mucoroides spores, however, appear not to possess a tight network of sporopollenin, since they were less resistant to acetolysis than those of the other species. The biological significance of the results is discussed with special reference to fruiting body formation.

scholarly journals Biochemical and cytological heterogeneity of the differentiating cells of the cellular slime mould Dictyostelium discoideum

1969 ◽  
Vol 114 (4) ◽  
pp. 815-818 ◽  
Author(s):  
Z. I. Miller ◽  
J. Quance ◽  
J M Ashworth
Keyword(s):  
Dictyostelium Discoideum ◽  
Buoyant Density ◽  
Cell Types ◽  
Posterior Region ◽  
Anterior Region ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Cellular Slime

1. The slug stage of the cellular slime mould Dictyostelium discoideum has been shown to contain two types of cell, which differ in buoyant density. 2. These two cell types also differ in cytological appearance and histochemical behaviour and have very different enzymic activities. 3. Evidence is presented suggesting that the lighter of these two cell types corresponds to cells from the posterior region of the slug (pre-spore cells) and the heavier of the two to cells from the anterior region of the slug (pre-stalk cells).

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