Organic Osmoregulatory Solutes in Cyanobacteria

Mackay, Mark A.; Norton, Raymond S.; Borowitzka, L. J.

doi:10.1099/00221287-130-9-2177

Cited by 146 publications

(169 citation statements)

References 38 publications

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“…Polyols were reported from eukaryotic algae and fungi (Avron, 1986;Wegmann, 1986;Jovall et al, 1990;Van Eck et al, 1989). Glycine betaine and sugars including sugar derivatives were predominantly found in phototrophic eubacteria (Galinski & Truper, 1982;Mackay et al, 1984). The accumulation of glycine betaine originally reported from aerobic heterotrophic eubacteria (Imhoff & RodriguezValera, 1984) was subsequently shown to result from growth media supplements (yeast extract) containing glycine betaine and/or suitable precursors (Wohlfarth et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

“…Compatible solute studies performed on marine and halophilic cyanobacteria (Mackay et al, 1984;Reed et d., 1986) have led to the proposal that the type of osmolyte employed reflects the salinity range suitable for the organism. Thus, the occurrence of betaine seemed to be typical for organisms of high salt tolerance.…”

Section: Separation and Quantijication Of Organic Osmolytes By Hplcmentioning

confidence: 99%

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The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Severin

Wohlfarth

Galinski

1992

Journal of General Microbiology

177

144

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The aim of this investigation was to perform an extensive screening using HPLC and I3C-NMR spectroscopy to disclose the spectrum of osmolytes produced by aerobic heterotrophic and anoxygenic phototrophic eubacteria. The most predominant solutes detected within a wide range of marine and halophilic micro-organisms were two recently discovered tetrahydropyrimidines ectoine and hydroxyectoine, which were synthesized in response to osmotic stress.

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Section: Introductionmentioning

confidence: 99%

Section: Separation and Quantijication Of Organic Osmolytes By Hplcmentioning

confidence: 99%

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Severin

Wohlfarth

Galinski

1992

Journal of General Microbiology

177

144

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“…PCC 6803 (Hagemann et al, 1987; Erdmann et al, 1992; for reviews see Joset et al, 1996; Hagemann and Erdmann, 1997, and references therein); and glycinebetaine is synthesized in salttolerant strains such as Synechococcus sp. PCC 7418 (Aphanothece halophytica; Mackay et al, 1984; Reed et al., 1986; for reviews, see Joset et al, 1996; Hagemann and Erdmann, 1997, and references therein). Direct evidence for the ability of these compatible solutes to…”

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confidence: 99%

Unsaturated Fatty Acids in Membrane Lipids Protect the Photosynthetic Machinery against Salt-Induced Damage inSynechococcus

et al. 2001

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In this study, the tolerance to salt stress of the photosynthetic machinery was examined in relation to the effects of the genetic enhancement of the unsaturation of fatty acids in membrane lipids in wild-type and desA ϩ cells of Synechococcus sp. PCC 7942. Wild-type cells synthesized saturated and mono-unsaturated fatty acids, whereas desA ϩ cells, which had been transformed with the desA gene for the ⌬12 acyl-lipid desaturase of Synechocystis sp. PCC 6803, also synthesized diunsaturated fatty acids. Incubation of wild-type and desA ϩ cells with 0.5 m NaCl resulted in the rapid loss of the activities of photosystem I, photosystem II, and the Na ϩ /H ϩ antiport system both in light and in darkness. However, desA ϩ cells were more tolerant to salt stress and osmotic stress than the wild-type cells. The extent of the recovery of the various photosynthetic activities from the effects of 0.5 m NaCl was much greater in desA ϩ cells than in wild-type cells. The photosystem II activity of thylakoid membranes from desA ϩ cells was more resistant to 0.5 m NaCl than that of membranes from wild-type cells. These results demonstrated that the genetically engineered increase in unsaturation of fatty acids in membrane lipids significantly enhanced the tolerance of the photosynthetic machinery to salt stress. The enhanced tolerance was due both to the increased resistance of the photosynthetic machinery to the salt-induced damage and to the increased ability of desA ϩ cells to repair the photosynthetic and Na ϩ /H ϩ antiport systems.Salt stress is one of the main environmental factors that limit the growth and productivity of plants and micro-organisms. We have been investigating the mechanisms of the hyperosmotic stress-induced and the salt stress-induced inactivation of the photosynthetic machinery, focussing on the oxygen-evolving machinery of the photosystem II complex, which is the system that is most susceptible to such environmental stress in Synechococcus sp. PCC 7942 (hereafter Synechococcus; Allakhverdiev et al., 2000aAllakhverdiev et al., , 2000b. Hyperosmotic stress due to 1.0 m sorbitol induces the efflux of water through water channels and reduces the volume of cells by more than 50%. This loss of water from the cytosol might be expected to increase the intracellular concentration of salts, and it leads to the rapid but reversible inactivation of the oxygenevolving machinery (Allakhverdiev et al., 2000b).Salt stress due to 0.5 m NaCl has both osmotic and ionic effects (Allakhverdiev et al., 2000a). The osmotic effect due to 0.5 m NaCl is not as strong as the effect of 1.0 m sorbitol and inactivates reversibly the oxygen-evolving machinery. The ionic effect of 0.5 m NaCl is caused by the influx of Na ϩ ions through K ϩ (Na ϩ ) channels and the resultant increase in the intracellular concentration of Na ϩ ions and counterpart anions that are mostly Cl Ϫ ions (Allakhverdiev et al., 2000a). These changes result in the irreversible inactivation of the oxygen-evolving machinery. As a consequence salt stress appears t...

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“…Inclusion of a 0.9-kb segment upstream of the BstEIIEcoRI fragment present in pKR47 resulted in a 7.5-fold higher level of choline oxidase activity (pKR32). Since the parental vector for both pKR47 and pKR32 is pKK223-3, which does not provide a translation initiation codon (6), the enhanced expression may be due to posttranscriptional events such as formation of RNA structures that could favor efficient translation when the 0.9-kb leader is present (16 (1,14,15,27,39,45). Alternatively, the steady-state concentration of betaine derived by oxidation of choline or from direct uptake of betaine may not be large enough to provide protection from the osmotic stress, due to further utilization of betaine.…”

Section: Discussionmentioning

confidence: 99%

“…The osmoprotective role of the quaternary ammonium compound glycine betaine (N,N,N-trimethylglycine; betaine) is evident in a number of diverse microbial systems, including enteric bacteria (1), soil bacteria (45), halophilic bacteria (15), cyanobacteria (27), and methanogenic archaebacteria (39). Accumulation of betaine as an adaptive strategy has also been demonstrated in plants (51,53).…”

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confidence: 99%

Choline oxidase, a catabolic enzyme in Arthrobacter pascens, facilitates adaptation to osmotic stress in Escherichia coli

1991

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Choline oxidase (EC 1.1.3.17) is a bifunctional enzyme that is capable of catalyzing glycine betaine biosynthesis from choline via betaine aldehyde. A gene (cox) encoding this enzyme in the gram-positive soil bacterium Arthrobacter pascens was isolated and characterized. This gene is contained within a 1.9-kb fragment that encodes a polypeptide of approximately 66 kDa. Transfer of this gene to an Escherichia coli mutant that is defective in betaine biosynthesis resulted in an osmotolerant phenotype. This phenotype was associated with the ability of the host to synthesize and assemble an enzymatically active choline oxidase that could catalyze biosynthesis of glycine betaine from an exogenous supply of choline. Although glycine betaine functions as an osmolyte in several different organisms, it was not found to have this role in A. pascens. Instead, both choline and glycine betaine were utilized as carbon sources. In A. pascens synthesis and activity of choline oxidase were modulated by carbon sources and were susceptible to catabolite repression. Thus, cox, a gene concerned with carbon utilization in A. pascens, was found to play a role in adaptation to an environmental stress in a heterologous organism. In addition to providing a possible means of manipulating osmotolerance in other organisms, the cox gene offers a model system for the study of choline oxidation, an important metabolic process in both procaryotes and eucaryotes.

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Organic Osmoregulatory Solutes in Cyanobacteria

Cited by 146 publications

References 38 publications

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Unsaturated Fatty Acids in Membrane Lipids Protect the Photosynthetic Machinery against Salt-Induced Damage inSynechococcus

Choline oxidase, a catabolic enzyme in Arthrobacter pascens, facilitates adaptation to osmotic stress in Escherichia coli

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