scholarly journals Folic acid and pterin deaminases in Dictyostelium discoideum: kinetic properties and regulation by folic acid, pterin, and adenosine 3',5'-phosphate.

1981 ◽  
Vol 148 (1) ◽  
pp. 183-192 ◽  
Author(s):  
B Wurster ◽  
F Bek ◽  
U Butz
Keyword(s):  
Folic Acid ◽  
Dictyostelium Discoideum ◽  
Kinetic Properties

scholarly journals Cyclic AMP and folic acid mediated cyclic GMP accumulation in Dictyostelium discoideum

FEBS Letters ◽  
1977 ◽  
Vol 79 (2) ◽  
pp. 331-336 ◽  
Author(s):  
José M. Mato ◽  
Peter J.M. Van Haastert ◽  
Frans A. Krens ◽  
Els H. Rhunsburger ◽  
Fred C.P.M. Dobbe ◽  
...  
Keyword(s):  
Folic Acid ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Cyclic Gmp

scholarly journals Sensory adaptation of Dictyostelium discoideum cells to chemotactic signals.

1983 ◽  
Vol 96 (6) ◽  
pp. 1559-1565 ◽  
Author(s):  
P J Van Haastert
Keyword(s):  
Folic Acid ◽  
Dictyostelium Discoideum ◽  
Background Level ◽  
Cell Aggregation ◽  
Constant Concentration ◽  
Camp Concentration ◽  
High Background ◽  
The Mean ◽  
Mean Concentration ◽  
Concentration Cells

Postvegetative Dictyostelium discoideum cells react chemotactically to gradients of cAMP, folic acid, and pterin. In the presence of a constant concentration of 10(-5) M cAMP cells move at random. They still are able to respond to superimposed gradients of cAMP, although the response is less efficient than without the high background level of cAMP. Cells which are accommodated to 10(-5) M cAMP do not react to a gradient of cAMP if the mean cAMP concentration is decreasing with time. This indicates the involvement of adaptation in the detection of chemotactic gradients: cells adapt to the mean concentration of chemoattractant and respond to positive deviations from the mean concentration. Cells adapted to high cAMP concentrations react normally to gradients of folic acid or pterin. Adaptation to one of these compounds does not affect the response to the other attractants. This suggests that cAMP, folic acid, and pterin are detected by different receptors, and that adaptation is localized at a step in the transduction process before the signals from these receptors coincide into one pathway. I discuss the implications of adaptation for chemotaxis and cell aggregation.

scholarly journals Evidence for a messenger function of cyclic GMP during phosphodiesterase induction in Dictyostelium discoideum

1982 ◽  
Vol 152 (1) ◽  
pp. 232-238
Author(s):  
P J van Haastert ◽  
F J Pasveer ◽  
R C van der Meer ◽  
P R van der Heijden ◽  
H van Walsum ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Folic Acid ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Cyclic Gmp ◽  
Close Correlation ◽  
Phosphodiesterase Activity ◽  
Transient Elevation ◽  
Lines Of Evidence ◽  
Stimulation Of

Chemotactic stimulation of vegetative or aggregative Dictyostelium discoideum cells induced a transient elevation of cyclic GMP levels. The addition of chemoattractants to postvegetative cells by pulsing induced phosphodiesterase activity. The following lines of evidence suggest a messenger function for cyclic GMP in the induction of phosphodiesterase: (i) Folic acid and cyclic AMP increased cyclic GMP levels and induced phosphodiesterase activity. (ii) Cyclic AMP induced both cyclic GMP accumulation and phosphodiesterase activity by binding to a rate receptor. (iii) The effects of chemical modification of cyclic AMP or folic acid on cyclic GMP accumulation and phosphodiesterase induction were closely correlated. (iv) A close correlation existed between the increase of cyclic GMP levels and the amount of phosphodiesterase induced, independent of the type of chemoattractant by which this cyclic GMP accumulation was produced. (v) Computer simulation of cyclic GMP binding to intracellular cyclic GMP-binding proteins indicates that half-maximal occupation by cyclic GMP required the same chemoattractant concentration as did half-maximal phosphodiesterase induction.

Oscillations and cell development in Dictyostelium discoideum stimulated by folic acid pulses

1977 ◽  
Vol 27 (1) ◽  
pp. 105-114
Author(s):  
B. Wurster ◽  
K. Schubiger
Keyword(s):  
Folic Acid ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Cell Development ◽  
Biochemical Oscillations ◽  
High Concentrations ◽  
Periodic Changes

Folic acid is known to be a chemoattractant of pre-aggregation cells of Dictyostelium discoideum. When supplied in pulses, folic acid induces biochemical oscillations and stimulates the development of pre-aggregation to aggregation-competent amoebae. The continuous supply of folic acid has no stimulatory effect. Folic-acid-induced oscillations are accompanied by periodic changes in the cyclic AMP concentration. Pulses of folic acid applied with rhythms between 7 and 11 min efficiently induce oscillations. In contrast, a rhythm of 2 min neither induces oscillations nor suppresses them. Cells start to oscillate with a rhythm of about 8 min. This inherent rhythm is independent of the inducing rhythm. Oscillating cells are less sensitive to folic acid than pre-oscillating ones. They respond only to high concentrations of folic acid which also interact with the oscillating system.

Folic acid, ascorbic acid and sodium selenite restore the motility of Dictyostelium discoideum inhibited by triethyllead

Toxicology ◽  
2002 ◽  
Vol 180 (3) ◽  
pp. 275-292 ◽  
Author(s):  
Jolanta Sroka ◽  
Zbigniew Madeja ◽  
Marta Michalik ◽  
Stanisław Przestalski ◽  
Włodzimierz Korohoda
Keyword(s):  
Ascorbic Acid ◽  
Folic Acid ◽  
Dictyostelium Discoideum ◽  
Sodium Selenite
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