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.

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 Enzyme synthesis in the cellular slime mould Dictyostelium discoideum during the differentiation of myxamoebae grown axenically

1972 ◽  
Vol 126 (3) ◽  
pp. 609-615 ◽  
Author(s):  
J. Quance ◽  
J. M. Ashworth
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Cell Differentiation ◽  
Dictyostelium Discoideum ◽  
Specific Activity ◽  
Enzyme Synthesis ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Cellular Slime ◽  
Developmental Programme

1. Myxamoebae of the cellular slime mould Dictyostelium discoideum Ax-2 were grown on different media, and were harvested either in the stationary or exponential phases of the growth cycle to yield samples of myxamoebae differing in enzymic composition. 2. Morphogenesis and cell differentiation phenomena in D. discoideum appear to be similar in myxamoebae grown and harvested under different conditions. 3. The specific activity of the enzymes β-N-acetylglucosaminidase, acid phosphatase, α-mannosidase, β-glucosidase and alkaline phosphatase have been determined during cell differentiation of myxamoebae grown and harvested under different conditions. 4. The pattern of synthesis of these enzymes, all of which have been claimed to be part of the ‘developmental programme’, either remains unaffected despite the origin of the myxamoebae (alkaline phosphatase) or is qualitatively similar but quantitatively affected (acid phosphatase, β-glucosidase) or is both qualitatively and quantitatively affected by changes in the myxamoebae (α-mannosidase, β-N-acetylglucosaminidase). 5. The implications of these results for the concept of a ‘developmental programme‘ are discussed.

Colchicine induces multiple axis formation and stalk cell differentiation in Dictyostelium discoideum

Development ◽  
1978 ◽  
Vol 47 (1) ◽  
pp. 195-206
Author(s):  
Danton H. O'Day ◽  
Antony J. Durston
Keyword(s):  
Cell Differentiation ◽  
Dictyostelium Discoideum ◽  
Immunofluorescent Staining ◽  
Stalk Cell ◽  
Axis Formation ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Long Time ◽  
Cellular Slime

Colchicine is shown to have several effects on the development of the pseudoplasmodia of the cellular slime mould Dictyostelium discoideum At concentrations of 0·01 M and above culmination was prevented, while differentiation of cells into stalk cells occurred at the rear of cell masses. Essentially all cells transformed into stalk cells when slugs were left on colchicine agar for a long time. At concentrations of 0·01 M normal slug architecture was maintained while above 0·025 M pseudoplasmodia reorganized into multiple mounds. Each of these mounds developed an apparently normal discrete tip which was devoid of prespore cells as shown by immunofluorescent staining. The same effects were observed in growing cultures and in regulating slugs treated with colchicine. The data are consistent with the ideas that microtubules are involved in the maintenance of slug architecture and in the differentiation of stalk cells. The modes by which these intracellular structures may operate in these functions are discussed.

scholarly journals 6-Phosphogluconate dehydrogenase and the assay of uridine diphosphate glucose pyrophosphorylase in the cellular slime mould Dictyostelium discoideum

1972 ◽  
Vol 126 (3) ◽  
pp. 593-600 ◽  
Author(s):  
T. D. Edmundson ◽  
J. M. Ashworth
Keyword(s):  
Cell Differentiation ◽  
Dehydrogenase Activity ◽  
Dictyostelium Discoideum ◽  
Specific Activity ◽  
Uridine Diphosphate ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Phosphogluconate Dehydrogenase ◽  
Cellular Slime ◽  
Diphosphate Glucose

1. 6-Phosphogluconate dehydrogenase activity is present in all morphogenetic stages during cell differentiation in the cellular slime mould. 2. The different ratios of 6-phosphogluconate dehydrogenase/UDP-glucose pyrophosphorylase observed during this process can render spectrophotometric assays of UDP-glucose pyrophosphorylase inaccurate. 3. The disputed occurrence of increases in specific activity of UDP-glucose pyrophosphorylase during cell differentiation in the cellular slime mould is discussed in the light of these observations.

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.

scholarly journals Glycogen synthetase and the control of glycogen synthesis in the cellular slime mould Dictyostelium discoideum during cell differentiation

1972 ◽  
Vol 126 (3) ◽  
pp. 627-633 ◽  
Author(s):  
B. D. Hames ◽  
G. Weeks ◽  
J. M. Ashworth
Keyword(s):  
Cell Differentiation ◽  
Glycogen Content ◽  
Control Mechanism ◽  
Glycogen Synthesis ◽  
Fruiting Bodies ◽  
Glycogen Synthetase ◽  
Stage 4 ◽  
Wide Range ◽  
Cellular Slime ◽  
Synthesis And Degradation

1. The variation in cellular glycogen content of differentiating cells derived from myxamoebae that initially contained a wide range of glycogen contents (0.047–5.56mg of glycogen/108myxamoebae) has been studied. 2. Myxamoebae that initially contained 0.047–3.62mg of glycogen/108myxamoebae all gave rise to fruiting bodies that contained similar amounts of glycogen (0.06–0.11mg of glycogen/108cells) but myxamoebae that initially contained 5.56mg of glycogen formed fruiting bodies containing 0.5mg of glycogen/108cells. 3. Despite the high net rate of glycogen disappearance (during cell differentiation) from cells that contained more than 2mg of glycogen/108cells initially, there were still significant variations in the rate of glycogen synthesis. The rate of glycogen synthesis reached a peak at the aggregation stage. 4. Evidence is presented showing that the rate of this synthesis of glycogen is controlled by factors other than the intracellular concentration of glycogen synthetase. 5. Our results are discussed in the context of the theory that the rates of glycogen synthesis and degradation act as a control mechanism for cell differentiation. 6. Criteria are discussed for deciding whether a biochemical event is causally or secondarily related to morphogenesis.

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.

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