ISSN:
0192-253X
Keywords:
morphogenesis
;
cAMP
;
ammonia
;
Dictyostelium discoideum
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Two compounds, ammonia (NH3) and 3′5′ cyclic AMP (cAMP) act as specific morphogens in regulating the development of Dictyostelium discoideum [1-11]. A previous study [12] demonstrated that NH3 at concentrations that affect the course of morphogenesis completely inhibits the extracellular release of cAMP by aggregation competent cells incubated in shaken suspension. The present study extends this finding in two respects: 1Exposure of aggregation competent cells to NH3 (supplied as ammonium carbonate) is followed within a few minutes by the complete disappearance of intracellular cAMP. Subsequent removal of NH3 is followed by a rapid, complete restoration of the level. Neither the disappearance nor the reappearance is affected by the presence of cycloheximide, an inhibitor of protein synthesis.2In a mutant strain of D discoideum, greatly increased sensitivity to NH3 as a regulator of morphogenesis is coupled with a correspondingly increased sensitivity to NH3 as an inhibitor of cAMP accumulation.These results are consistent with a recently proposed [13, 14] model of morphogenetic regulation that is based on the supposition that NH3, by inhibiting cAMP production, restricts cAMP accumulation to specified constrained areas within the developing multicellular aggregate and thereby dictates the course of morphogenesis and cytodifferentiation.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/dvg.1020010104
