Metabolism of major cell components during slime mold morphogenesis.

Brandeis University, Department of Biology, Waltham, Mass.U.S.A.
Biochimica et Biophysica Acta (Impact Factor: 4.66). 11/1961; 53:285-93. DOI: 10.1016/0006-3002(61)90441-3
Source: PubMed

ABSTRACT Morphogenetically synchronized Dictyostelium discoideum amoeba were sampled at intervals during development to determine the fates of major cell constituents. Dry weight, total protein and fractions thereof, RNA, free and bound hexoses were followed. None of these except the last appeared to reflect the specific morphogenetic events. Two polysaccharide fractions were encountered which did reflect these events and their syntheses were repressed or disturbed in morphogenetically deficient mutants.

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    ABSTRACT: Cell-free extracts of Dictyostelium discoideum contained the enzymes necessary for both oxidative and non-oxidative pentose phosphate metabolism. The specific activities of these enzymes changed little during differentiation. The properties of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were studied with respect to K, values for substrates and cofactor NADPf. The two dehydrogenases were relatively unstable in extracts prepared from early stages of development. The K, value of phospho- glucose isomerase for glucose 6-phosphate was approximately 30-fold higher than that of glucose-6-phosphate dehydrogenase. Measurements of pentose phosphate pathway inter- mediates were made throughout development. All measured intermediates except fructose 1,6-bisphosphate appeared to accumulate between aggregation and culmination. Fructose 1,6-bisphosphate concentrations remained constant until culmination, then dropped 3-fold during sorocarp construction. Calculation of mass-action ratios for the pentose phosphate reactions suggested that glucose-6-phosphate dehydrogenase was the only reaction greatly displaced from equilibrium. These results are discussed in relation to factors controlling pentose phosphate metabolism during development in D. discoideum.
    Journal of general microbiology 08/1979; 113(2):357-368. DOI:10.1099/00221287-113-2-357
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    Journal of general microbiology 09/1990; 136(9). DOI:10.1099/00221287-136-9-1739
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    Transactions of the British Mycological Society 08/1972; 59(1). DOI:10.1016/S0007-1536(72)80041-X