Pattern formation in Dictyostelium discoideum

Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 215-228
Author(s):  
D. Forman ◽  
D. R. Garrod
Keyword(s):  
Life Cycle ◽  
Pattern Formation ◽  
Dictyostelium Discoideum ◽  
Cell Population ◽  
Growth Conditions ◽  
Total Cell ◽  
Immunofluorescent Staining ◽  
Fruiting Bodies ◽  
Fluorescent Intensity ◽  
Total Cell Population

Immunofluorescent staining of the prespore cells of the cellular slime mould Dictyostelium discoideum was carried out using a heterologous spore antibody. The highly specific staining of the prespore vesicles (PSVs) within the prespore cells enabled quantitative determinations to be made of the rate and extent of development of these cells throughout the life cycle. The results showed that PSVs first appeared in a large proportion of the cells shortly after the cells had chemotactically aggregated into multicellular masses. During the later phases of the life cycle, the proportion of cells containing PSV increased, as did the fluorescent intensity of their PSVs, until the early culmination stage of development when 85–90 % of the total cell population contained PSVs. Lowering the temperature of development delayed the onset of vesicle formation and decreased the proportion of prespore cells in the total cell population. Changing the growth conditions of the cells prior to multicellular development also had a significant effect on the proportions of prespore cells, as did the use of a mutant known to give rise to fruiting bodies with a reduced number of spores. The comparability between these estimates of prespore cell proportions at culmination and previously reported spore:stalk ratios within fruiting bodies confirms the view that PSVs are reliable indicators of prespore cells. The finding that temperature and growth conditions and the use of mutants all of which are known to affect spore:stalk ratios, also all affected prespore proportions in the expected direction, adds further weight to this argument. The fact that prespore cells are beginning to differentiate early in the multicellular phase of the life cycle and the related finding that such differentiation always precedes formation of the grex tip are results of considerable importance to the development of a model for pattern formation in D. discoideum.

scholarly journals Selection of chemotaxis mutants of Dictyostelium discoideum.

1987 ◽  
Vol 104 (1) ◽  
pp. 151-161 ◽  
Author(s):  
J E Segall ◽  
P R Fisher ◽  
G Gerisch
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Population ◽  
Selection Procedure ◽  
Total Cell ◽  
Wild Type ◽  
Total Cell Population ◽  
Mutant Cells ◽  
Efficient Selection ◽  
Filter Layer ◽  
Selection Of

A method has been developed for the efficient selection of chemotaxis mutants of Dictyostelium discoideum. Mutants defective in the chemotactic response to folate could be enriched up to 30-fold in one round of selection using a chamber in which a compartment that contained the chemoattractant was separated by a sandwich of four nitrocellulose filters from a compartment that contained buffer. Mutagenized cells were placed in the center of the filter layer and exposed to the attractant gradient built up between the compartments for a period of 3-4 h. While wild-type cells moved through the filters in a wave towards the compartment that contained attractant, mutant cells remained in the filter to which they were applied. After several repetitions of the selection procedure, mutants defective in chemotaxis made up 10% of the total cell population retained in that filter. Mutants exhibiting three types of alterations were collected: motility mutants with either reduced speed of movement, or altered rates of turning; a single mutant defective in production of the attractant-degrading enzyme, folate deaminase; and mutants with normal motility but reduced chemotactic responsiveness. One mutant showed drastically reduced sensitivity in folate-induced cGMP production. Morphogenetic alterations of mutants defective in folate chemotaxis are described.

scholarly journals Total Cell Counts of the Bone Marrow of Normal Albino Rats from 1 to 50 Weeks of Age

Blood ◽  
1959 ◽  
Vol 14 (4) ◽  
pp. 409-414 ◽  
Author(s):  
WILLIAM T. BURKE ◽  
CHARLES HARRIS
Keyword(s):  
Bone Marrow ◽  
Cell Population ◽  
Normal Values ◽  
Age Groups ◽  
Considerable Change ◽  
Total Cell ◽  
Albino Rats ◽  
Cell Counts ◽  
Total Cell Population ◽  
Femoral Bone Marrow

Abstract A method is described by which the total nucleated cell count of femoral bone marrow of the rat can be estimated and cell population expressed in terms of differential counts. Normal values of total nucleated cell counts and the cellular distributions are given for seven age groups. These data indicate considerable change in bone marrow total cell population in rats one to 10 weeks of age.

scholarly journals Mitochondrial processing peptidase activity is controlled by the processing of α-MPP during development in Dictyostelium discoideum

Microbiology ◽  
2010 ◽  
Vol 156 (4) ◽  
pp. 978-989 ◽  
Author(s):  
Koki Nagayama ◽  
Tetsuo Ohmachi
Keyword(s):  
Life Cycle ◽  
Dictyostelium Discoideum ◽  
Early Development ◽  
Normal Development ◽  
Peptidase Activity ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Formation Stage ◽  
Mitochondrial Processing Peptidase ◽  
Processing Peptidase

We investigated the expression of the α subunit of the Dictyostelium mitochondrial processing peptidase (Ddα-MPP) during development. Ddα-MPP mRNA is expressed at the highest levels in vegetatively growing cells and during early development, and is markedly downregulated after 10 h of development. The Ddα-MPP protein is expressed as two forms, designated α-MPPH and α-MPPL, throughout the Dictyostelium life cycle. The larger form, α-MPPH, is cleaved to produce the functional α-MPPL form. We were not able to isolate mutants in which the α-mpp gene had been disrupted. Instead, an antisense transformant, αA2, expressing α-MPP at a lower level than the wild-type AX-3 was isolated to examine the function of the α-MPP protein. Development of the αA2 strain was normal until the slug formation stage, but the slug stage was prolonged to ∼24 h. In this prolonged slug stage, only α-MPPH was present, and α-MPPL protein and MPP activity were not detected. After 28 h, α-MPPL and MPP activity reappeared, and normal fruiting bodies were formed after a delay of approximately 8 h compared with normal development. These results indicate that MPP activity is controlled by the processing of α-MPPH to α-MPPL during development in Dictyostelium.

Erythropoiesis in peripheral blood of tuatara (Sphenodon punctatus) and turtle (Malaclemys terrapin)

1970 ◽  
Vol 48 (2) ◽  
pp. 209-212 ◽  
Author(s):  
Vibeke E. Engelbert ◽  
Ann Dorothy Young
Keyword(s):  
Cell Population ◽  
Peripheral Blood ◽  
Total Cell ◽  
Red Cells ◽  
Malaclemys Terrapin ◽  
Domestic Birds ◽  
Total Cell Population ◽  
Sphenodon Punctatus ◽  
Clone Cells

Erythropoiesis in peripheral blood of domestic birds was shown earlier to arise directly from the nucleus of mature erythrocytes as nuclear protuberations that later broke free. Three to seven percent of new red cells originated in this way from clone cells.Investigations of peripheral blood in reptiles has further demonstrated formation of nucleated red cells as clones from nuclear buds of mature erythrocytes. Clone cells plus new immature red cells constitute, in Sphenodon punctatus, 8–18% and, in turtle, Malaclemys terrapin, 18–25% of the total cell population. Some lymphocytes and granulocytes appear also to arise from nuclear buds. Thrombocytes were present in some animals, absent in others, but were not counted in the present work.

SPHEROPLAST INDUCTION AND LYSIS OF BCG STRAINS BY GLYCINE AND LYSOZYME

1966 ◽  
Vol 12 (2) ◽  
pp. 255-261 ◽  
Author(s):  
H. Sato ◽  
B. B. Diena ◽  
L. Greenberg
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cell Population ◽  
Lithium Chloride ◽  
Synthetic Medium ◽  
Total Cell ◽  
Cell Populations ◽  
Standard Curve ◽  
Total Cell Population

Spheroplast induction and lysis of 6 BCG strains of Mycobacterium tuberculosis by glycine and lysozyme was studied in various media. Spheroplast production was noted in only three strains involving 20% of cell populations. Lysis, as distinct from spheroplast induction, occurred in Dubos medium containing 1.5% glycine and 0.01% lysozyme after 24–48 hours of incubation. Estimation from a standard curve indicated 40 to 70% lysis of the total cell population after 7–10 days of incubation.Similarly, lysis of BCG cells occurred when the inducers, glycine, lysozyme, and lithium chloride, were added to nitrogen-starved cultures grown in Aldridge synthetic medium for 7 to 8 days.

scholarly journals TOTAL CELL NUMBER IN FETAL BRAIN

2011 ◽  
Vol 19 (1) ◽  
pp. 35 ◽  
Author(s):  
Grethe Badsberg Samuelsen ◽  
Nenad Bogdanović ◽  
Henning Laursen ◽  
Niels Graem ◽  
Jørgen Falck Larsen ◽  
...  
Keyword(s):  
Birth Weight ◽  
Cell Population ◽  
Fetal Brain ◽  
Fold Increase ◽  
Cell Number ◽  
Total Cell ◽  
Cortical Plate ◽  
Total Cell Number ◽  
Normal Birth ◽  
Total Cell Population

In this study the material comprises brains from three aborted fetuses and two fullterm infants who died at birth.The gestational ages ranged from the 22nd week to term. All cases were without malformations, known chromosomal abnormality, hydrops, and systemic infections, and all had normal birth weights with fetal growth indices (observed birth weight/expected mean birth weight) between 0.9 - 1.05. The preliminary results show a five fold increase in the total cell population in the marginal zone/cortical plate, MZ/CP (future neocortex), from week 22 until term. In the transient subplate zone, SP, the total cell number was more than doubled from week 22 to week 30-35, and then decreased towards term. In the intermediate zone, IZ (future white matter), the total cell population was doubled from week 22 until term. The total cell number in the entricular/subventricular zone, VZ/SZ (germinal matrix), was reduced by a factor of five from week 22 until term. A histological differentiation between neurons and glial cells was not possible. The optical fractionator was used to estimate the total cell population in four characteristic developmental zones in the human fetal brain. Fetal brain tissue undergoes considerable and rather unpredictable shrinkage during fixation. However, using the fractionator principle it is possible to eliminate this problem, provided that the structure of interest (one brain hemisphere) is fully intact.

EFFECT OF THE CESSATION OF THIOURACIL ADMINISTRATION ON THE CELL POPULATION OF THE THYROID OF RATS

1957 ◽  
Vol 16 (1) ◽  
pp. 1-8 ◽  
Author(s):  
JOYCE E. SANTLER
Keyword(s):  
Thyroid Gland ◽  
Blood Vessel ◽  
Cell Population ◽  
Stromal Cells ◽  
Stromal Cell ◽  
Normal Values ◽  
Total Cell ◽  
Albino Rats ◽  
Follicular Cells ◽  
Total Cell Population

SUMMARY The thyroid gland of adult male albino rats enlarged during a period of 30 days of thiouracil treatment. During 75 days after cessation of this treatment there was a regression of the enlarged gland, but not to normal values of weight, volume or total cell population. The regression did not, however, involve any appreciable drop in the numbers of follicular cells. Decrease in the volume of follicular tissue was therefore due to shrinkage of individual follicular cells. The stromal cell population decreased, especially during the first 7 days after the withdrawal of thiouracil, and at the end of the experiment the proportion of stromal cells to follicular cells had returned to normal. The first 7 days was also the time of greatest regression in weight, volume and blood vessel space in the thyroid, these values showing only slight further reduction in the groups killed 30 and 75 days after the withdrawal of goitrogen.

Cellular proliferation in complicated versus uncomplicated atherosclerotic lesions: Total cell population, foam cells and newly formed microvessels

2009 ◽  
Vol 41 (6) ◽  
pp. 408-413 ◽  
Author(s):  
P. Manolakou ◽  
R. Angelopoulou ◽  
C. Bakoyiannis ◽  
E. Psathas ◽  
E. Bastounis ◽  
...  
Keyword(s):  
Cell Population ◽  
Cellular Proliferation ◽  
Foam Cells ◽  
Total Cell ◽  
Atherosclerotic Lesions ◽  
Total Cell Population

scholarly journals Rates of accumulation of glycosidase activities during growth and differentiation of Dictyostelium discoideum

1975 ◽  
Vol 148 (2) ◽  
pp. 161-167 ◽  
Author(s):  
D Every ◽  
J M Ashworth
Keyword(s):  
Life Cycle ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Growth Medium ◽  
Specific Activity ◽  
Growth Conditions ◽  
Cellular Protein ◽  
Total Cellular Protein ◽  
Early Differentiation ◽  
Rate Of Accumulation

1. The rates of accumulation (enzyme units/h per 10(8) cells) of a number of glycosidase activities were studied in Dictyostelium discoideum cells during the growth and differentiation phases of this organism's life cycle. 2. The rates of accumulation of the enzymes β-N-acetylglucosaminidase, α-glucosidase and β-galactosidase remain unchanged during the growth and early differentiation phases. 3. The considerable changes in specific activity of the enzymes which occur in the early differentiation phase are due to the massive loss of total cellular protein which occurs at this time. 4. Significant alterations can occur in the rates of accumulation of α-mannosidase during both the growth and differentiation phases, and since, on the onset of differentiation, β-glucosidase activity is excreted and degraded, the rate of accumulation of this enzyme differs in the growth and differentiation phases. 5. The characteristic rates of accumulation of all these glycosidases change markedly with changes in the growth conditions of the myxamoebae, and thus these rates of synthesis must be regulated independently; however, addition of cyclic AMP to the growth medium has no effect on them.

scholarly journals Mathematical models incorporating a multi-stage cell cycle replicate normally-hidden inherent synchronization in cell proliferation

2019 ◽  
Vol 16 (157) ◽  
pp. 20190382 ◽  
Author(s):  
Sean T. Vittadello ◽  
Scott W. McCue ◽  
Gency Gunasingh ◽  
Nikolas K. Haass ◽  
Matthew J. Simpson
Keyword(s):  
Experimental Data ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Population ◽  
Total Cell ◽  
Fluorescent Cell ◽  
Multi Stage ◽  
Total Cell Population ◽  
Cycle Dependent ◽  
Proliferation Assays

We present a suite of experimental data showing that cell proliferation assays, prepared using standard methods thought to produce asynchronous cell populations, persistently exhibit inherent synchronization. Our experiments use fluorescent cell cycle indicators to reveal the normally hidden cell synchronization, by highlighting oscillatory subpopulations within the total cell population. These oscillatory subpopulations would never be observed without these cell cycle indicators. On the other hand, our experimental data show that the total cell population appears to grow exponentially, as in an asynchronous population. We reconcile these seemingly inconsistent observations by employing a multi-stage mathematical model of cell proliferation that can replicate the oscillatory subpopulations. Our study has important implications for understanding and improving experimental reproducibility. In particular, inherent synchronization may affect the experimental reproducibility of studies aiming to investigate cell cycle-dependent mechanisms, including changes in migration and drug response.

Sign in / Sign up

Export Citation Format

Share Document