scholarly journals Metabolism of the cellular slime mould Dictyostelium discoideum grown in axenic culture

1970 ◽  
Vol 119 (2) ◽  
pp. 175-182 ◽  
Author(s):  
J. M. Ashworth ◽  
D. J. Watts
Keyword(s):  
Dictyostelium Discoideum ◽  
Wild Type Strain ◽  
Specific Activity ◽  
Axenic Culture ◽  
Acid Oxidation ◽  
Wild Type ◽  
Free Sugars ◽  
Slime Mould ◽  
Cellular Slime ◽  
Carbohydrate Contents

1. The DNA, RNA, protein and carbohydrate contents of myxamoebae of Dictyostelium discoideum strain Ax-2 were measured after growth on bacteria or in various axenic media. 2. Myxamoebae grown in the different axenic media have similar DNA, RNA and protein contents, but there are marked differences in the contents of glycogen and free sugars. The DNA and protein contents of myxamoebae grown on bacteria are different from those in myxamoebae grown axenically. 3. Approximately half the DNA found in myxamoebae grown on bacteria is of bacterial rather than of slime-mould origin. 4. The specific activities of some enzymes (including UDP-glucose pyrophosphorylase) are higher in myxamoebae grown axenically than in myxamoebae grown on bacteria. Nevertheless the characteristic increase in the specific activity of UDP-glucose pyrophosphorylase occurring during differentiation of cells of the wild-type strain NC-4 is also found in cells grown axenically. 5. The rate of amino acid oxidation during axenic growth of the myxamoebae is decreased when the cells are supplied with glucose.

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.

The age-dependent loss of cells from the rear of a Dictyostelium discoideum slug is not tip controlled

Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 61-67
Author(s):  
Elizabeth Smith ◽  
Keith L. Williams
Keyword(s):  
Dictyostelium Discoideum ◽  
Type Strain ◽  
Wild Type Strain ◽  
Organizer Region ◽  
Cell Loss ◽  
Wild Type ◽  
Reciprocal Transplants ◽  
Age Dependent ◽  
Dependent Cell ◽  
Cellular Slime

Young slugs of the cellular slime mould Dictyostelium discoideum drop small numbers of individual amoebae (∼ 10/mm) in the slime trail. With increased time of migration, slugs develop trailing tails and leave clumps of cells in their slime trails. Using reciprocal transplants between tips of young and old slugs and between a wild-type strain and an ‘aged'’ mutant it was shown that this age-dependent cell loss is due to changes in the bulk of cells comprising the slug, rather than to changes in the effectiveness of the tip (organizer region). Another property of the slug, the decision to continue migrating or form a fruiting body which is controlled by the tip, was less affected by age. This raises the possibility that cell autonomous properties of the slug are more subject to ageing than is the tip.

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.

scholarly journals Enzyme synthesis in myxamoebae of the cellular slime mould Dictyostelium discoideum during growth in axenic culture

1972 ◽  
Vol 126 (3) ◽  
pp. 601-608 ◽  
Author(s):  
J. M. Ashworth ◽  
J. Quance
Keyword(s):  
Dictyostelium Discoideum ◽  
Axenic Culture ◽  
Growth Cycle ◽  
Enzyme Synthesis ◽  
Intracellular Location ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Intracellular Fraction ◽  
Cellular Slime ◽  
Specific Activities

1. The specific activities of β-N-acetylglucosaminidase, acid phosphatase, α-mannosidase, β-glucosidase, UDP-glucose pyrophosphorylase and alkaline phosphatase have been determined in myxamoebae of the cellular slime mould Dictyostelium discoideum Ax-2 grown on different media and in different phases of the growth cycle. 2. Variations in enzymic composition occur with changes in growth medium and phase of the growth cycle. 3. The intracellular location of the enzymes studied has been determined. 4. Two enzymes, β-N-acetylglucosaminidase and α-mannosidase, are not only synthesized preferentially as the myxamoebae enter the stationary phase of growth but they are also excreted. The excretion process appears to be specific, because other enzymes that occur in the same intracellular fraction are not excreted.

scholarly journals Construction and Characterization of aMycobacterium tuberculosis Mutant Lacking the Alternate Sigma Factor Gene, sigF

2000 ◽  
Vol 68 (10) ◽  
pp. 5575-5580 ◽  
Author(s):  
Ping Chen ◽  
Rafael E. Ruiz ◽  
Qing Li ◽  
Richard F. Silver ◽  
William R. Bishai
Keyword(s):  
Stationary Phase ◽  
Sigma Factor ◽  
Type Strain ◽  
Wild Type Strain ◽  
Axenic Culture ◽  
Wild Type ◽  
Intracellular Growth ◽  
Factor Gene ◽  
Time To Death

ABSTRACT The alternate RNA polymerase sigma factor gene, sigF, which is expressed in stationary phase and under stress conditions in vitro, has been deleted in the virulent CDC1551 strain ofMycobacterium tuberculosis. The growth rate of the ΔsigF mutant was identical to that of the isogenic wild-type strain in exponential phase, although in stationary phase the mutant achieved a higher density than the wild type. The mutant showed increased susceptibility to rifampin and rifapentine. Additionally, the ΔsigF mutant displayed diminished uptake of chenodeoxycholate, and this effect was reversed by complementation with a wild-type sigF gene. No differences in short-term intracellular growth between mutant and wild-type organisms within human monocytes were observed. Similarly, the organisms did not differ in their susceptibilities to lymphocyte-mediated inhibition of intracellular growth. However, mice infected with the ΔsigF mutant showed a median time to death of 246 days compared with 161 days for wild-type strain-infected animals (P < 0.001). These data indicate that M. tuberculosis sigF is a nonessential alternate sigma factor both in axenic culture and for survival in macrophages in vitro. While the ΔsigF mutant produces a lethal infection of mice, it is less virulent than its wild-type counterpart by time-to-death analysis.

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.

Sign in / Sign up

Export Citation Format

Share Document