A characterization of the preaggregative period of Dictyostelium discoideum

• Published in: Developmental biology Vol. 110; no. 1; pp. 157 - 170
• Main Authors: Finney, Robert E., Langtimm, Carol J., Soll, David R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.07.1985; Elsevier
• Subjects: AGGREGATION; ANALISIS ESTADISTICO; ANALYSE STATISTIQUE; Binding Sites; Biological and medical sciences; Cell Aggregation; Cell Communication; Cell differentiation, maturation, development, hematopoiesis; Cell physiology; CHAMPIGNON; Culture Media; Cyclic AMP - metabolism; DEVELOPMENTAL STAGES; Dictyostelium - cytology; Dictyostelium discoideum; ETAPAS DE DESARROLLO; ETAPAS DE DESARROLLO DE LA PLANTA; Fundamental and applied biological sciences. Psychology; Fungal Proteins - biosynthesis; FUNGI; Molecular and cellular biology; PLANT DEVELOPMENTAL STAGES; PROTEIN SYNTHESIS; Receptors, Cyclic AMP - metabolism; SINTESIS DE PROTEINAS; STADE DE DEVELOPPEMENT; STADE DE DEVELOPPEMENT VEGETAL; STATISTICAL ANALYSIS; SYNTHESE PROTEIQUE; Time Factors; Dictyostelium discoideum; Protozoa; Regulation(control); Cell-cell interaction; Protein synthesis; Cyclic AMP; Development; Cell differentiation; Mycetozoa
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/0012-1606(85)90073-9

The preaggregative period of Dictyostelium discoideum has been characterized by measuring the reduction in time for the onset of aggregation under conditions which hinder close cell-cell associations, inhibit protein synthesis, and/or include continuous high concentrations or pulsed low concentrations of exogenous cAMP. The results demonstrate that: (1) the preaggregative period (normally 7 hr for cells from log phase cultures) can be dissected into two distinct components: an initial component which includes the first 4.5 hr, and a second component which includes the last 2.5 hr; (2) the first component will progress at normal rate in the continuous absence of close cell-cell associations (as single amoebae in suspension) or in the continuous absence of de novo protein synthesis; (3) the second component will not progress in the continuous absence of close cell-cell associations or de novo protein synthesis; (4) high concentrations of cAMP continuously present in suspension cultures do not affect progress through the first component, nor do they support progress through the second component; (5) however, if cells are allowed to form close cell-cell associations during progress through the first component, high concentrations of cAMP will support progress through the second component in the absence of close cell-cell associations; (6) these associations, which render cells sensitive to cAMP, will occur in the absence of de novo protein synthesis and before the acquisition of contact sites A; (7) these associations may be completely bypassed if suspended cells are continuously pulsed with low concentrations of cAMP; in this case, pulses of cAMP will support progress through the final component in continuous suspension cultures; and (8) the acquisition of contact sites A will not occur in the absence of progress through the second component; in contrast, the acquisition of cAMP binding sites on the cell's surface will occur. These results are considered in terms of the complexity and regulation of the preaggregative period of Dictyostelium.