Abstract
We describe a mutant (strain 704) of the obligate photoautotroph Anacystis nidulans which behaves like the wild type under continuous illumination but which in the dark rapidly loses viability, respires little, and incorporates label into ribonucleic acid and protein at rates considerably less than observed with the darkened wild type. Extracts of this mutant strain show no detectable 6-phosphogluconate dehydrogenase (EC 1.1.1.44) activity. Spontaneous revertants of mutant 704 were selected as survivors of prolonged incubation in darkness. Of 10 such strains examined, none had regained 6-phosphogluconate dehydrogenase activity, and all had lost detectable glucose-6-phosphate dehydrogenase (EC 1.1.1.49) activity. Although dark survival of these revertants paralleled that of the wild type, rates of dark endogenous respiration and incorporation of labeled precursors into ribonucleic acid were still very low, comparable to those observed with strain 704. These results are consistent with the following hypotheses concerning dark endogenous metabolism in unicellular blue-green bacteria. (i) Although the oxidative pentose phosphate cycle (hexose monophosphate shunt) may play a major role in endogenous metabolism in A. nidulans, as proposed by others, it is not the only pathway capable of providing energy for maintenance of viability in darkness. (ii) Much of the endogenous metabolic activity (respiration and macromolecular synthesis) observed in darkened cultures of wild-type A. nidulans is not required for survival alone, and must therefore serve other functions.
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- DAWES E. A., RIBBONS D. W. The endogenous metabolism of microorganisms. Annu Rev Microbiol. 1962;16:241–264. doi: 10.1146/annurev.mi.16.100162.001325. [DOI] [PubMed] [Google Scholar]
- Dawes E. A., Senior P. J. The role and regulation of energy reserve polymers in micro-organisms. Adv Microb Physiol. 1973;10:135–266. doi: 10.1016/s0065-2911(08)60088-0. [DOI] [PubMed] [Google Scholar]
- Dobson P. R., Doolittle W. F., Sogin M. L. Precursor of 5S ribosomal ribonucleic acid in the blue-green alga Anacystis nidulans. J Bacteriol. 1974 Feb;117(2):660–666. doi: 10.1128/jb.117.2.660-666.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Doolittle W. F. Postmaturational cleavage of 23s ribosomal ribonucleic acid and its metabolic control in the blue-green alga Anacystis nidulans. J Bacteriol. 1973 Mar;113(3):1256–1263. doi: 10.1128/jb.113.3.1256-1263.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Govons S., Vinopal R., Ingraham J., Preiss J. Isolation of mutants of Escherichia coli B altered in their ability to synthesize glycogen. J Bacteriol. 1969 Feb;97(2):970–972. doi: 10.1128/jb.97.2.970-972.1969. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Pelroy R. A., Rippka R., Stanier R. Y. Metabolism of glucose by unicellular blue-green algae. Arch Mikrobiol. 1972;87(4):303–322. doi: 10.1007/BF00409131. [DOI] [PubMed] [Google Scholar]
- Shepherd D., Rosenthal S., Lundblad G. T., Segel I. H. Neurospora crassa glycogen phosphorylase: characterization and kinetics via a new radiochemical assay for phosphorolysis. Arch Biochem Biophys. 1969 Dec;135(1):334–340. doi: 10.1016/0003-9861(69)90547-5. [DOI] [PubMed] [Google Scholar]
- Stanier R. Y., Kunisawa R., Mandel M., Cohen-Bazire G. Purification and properties of unicellular blue-green algae (order Chroococcales). Bacteriol Rev. 1971 Jun;35(2):171–205. doi: 10.1128/br.35.2.171-205.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]