Osmotic adjustment and organic solute accumulation in unicellular cyanobacteria from freshwater and marine habitats

Reed, Robert H.; Stewart, W. D. P.

doi:10.1007/bf00393037

Cited by 152 publications

(118 citation statements)

References 30 publications

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“…1b and 2b;Reed and Stewart, 1985), the trehalose accumulation capacity may be relevant to the tolerance of the extremely desiccating environment of terrestrial cyanobacteria. As N. punctiforme cells contained approximately 5.7 mg Chl g 1 DW, the amount of trehalose normalized to chlorophyll levels is 2.4 μg μg 1 Chl.…”

Section: Discussionmentioning

confidence: 99%

Water-stress induced trehalose accumulation and control of trehalase in the cyanobacterium Nostoc punctiforme IAM M-15

Yoshida

Sakamoto

2009

J. Gen. Appl. Microbiol.

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Section: Discussionmentioning

confidence: 99%

Water-stress induced trehalose accumulation and control of trehalase in the cyanobacterium Nostoc punctiforme IAM M-15

Yoshida

Sakamoto

2009

J. Gen. Appl. Microbiol.

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“…PCC 6803 and Synechocystis sp. PCC 6714 (15)(16)(17)(18)(19). The other indication of the involvement of the KtrB system in long term osmoadapatation (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Under these conditions a variety of these species synthesize high concentrations of glucosylglycerol and sucrose, which are accumulated as compatible solutes in their cytoplasm (15). During the early phase of this adaptation Synechocystis sp.…”

mentioning

confidence: 99%

Na+-dependent K+ Uptake Ktr System from the Cyanobacterium Synechocystis sp. PCC 6803 and Its Role in the Early Phases of Cell Adaptation to Hyperosmotic Shock

Matsuda

Kobayashi

Katoh

et al. 2004

Journal of Biological Chemistry

107

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Transmembrane ion transport processes play a key role in the adaptation of cells to hyperosmotic conditions. Previous work has shown that the disruption of a ktrB/ntpJ-like putative Na ؉ /K ؉ transporter gene in the cyanobacterium Synechocystis sp. PCC 6803 confers increased Na ؉ sensitivity, and inhibits HCO 3 ؊ uptake. Here, we report on the mechanistic basis of this effect. Heterologous expression experiments in Escherichia coli show that three Synechocystis genes are required for K ؉ transport activity. They encode an NAD ؉ -binding peripheral membrane protein (ktrA; sll0493), an integral membrane protein, belonging to a superfamily of K ؉ transporters (ktrB; formerly ntpJ; slr1509), and a novel type of ktr gene product, not previously found in Ktr systems (ktrE; slr1508). In E. coli, Synechocystis KtrABEmediated K ؉ uptake occurred with a moderately high affinity (K m of about 60 M), and depended on both Na ؉ and a high membrane potential, but not on ATP. KtrABE neither mediated Na ؉ uptake nor Na ؉ efflux. In Synechocystis sp. PCC 6803, KtrB-mediated K ؉ uptake required Na ؉ and was inhibited by protonophore. A ⌬ktrB strain was sensitive to long term hyperosmotic stress elicited by either NaCl or sorbitol. Hyperosmotic shock led initially to loss of net K ؉ from the cells. The ⌬ktrB cells shocked with sorbitol failed to reaccumulate K ؉ up to its original level. These data indicate that in strain PCC 6803 K ؉ uptake via KtrABE plays a crucial role in the early phase of cell turgor regulation after hyperosmotic shock.

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“…The rapid changes in volume of microalgae are under the control of 2 factors: (1) variation of internal ion concentration (Riisgbrd et al 1980); (2) variation of low molecular weight metabolites of photosynthetic origin (Ahmad & Hellebust 1985, Dor 1985, Reed & Stewart 1985. For the crysophyceae Ochromonas malhamensis ca 70 to 80 % of osmotic activity is due to an increase in a small carbohydrate (isoflondoside), whereas 20 to 30 % is due to an increase in free amino acids or in K+ (Aaronson 1980).…”

Section: Cell Volumementioning

confidence: 99%

Adaptation of biochemical composition and cell size to irradiance in two microalgae: possible ecological implications

Claustre¹,

Gostan²

1987

Mar. Ecol. Prog. Ser.

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Two marine microalgae (Haptophyceae), Hymenornonas elongata and Isochrysis galbana, were grown in turbidostats in order to investigate the influence of light intensity on cell volume and biochemical composition. At irradiance levels that saturated growth (400pE m-2 S-'), the algae contained a high level of carbon compounds, especially soluble sugars. At the irradiance that limited growth (25 pE m-2 S-') sugar pools were lower for the 2 algae and H. elongata decreased its volume by 25 %. In the transitional phase that followed a shift from 400 pE m-2 S-' to 25 pE m-2 S-' rates at which biochemical ratios reached stability differed for the 2 algae. Re-establishing high light intensity after a period under low light intensity influenced algal volume in H. elongata; t h s event followed a particular lunetic pattern that we attempt to explain on theoretical grounds. Results are discussed with regard to durations of irradiance perturbations that can occur in the sea.

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Osmotic adjustment and organic solute accumulation in unicellular cyanobacteria from freshwater and marine habitats

Cited by 152 publications

References 30 publications

Water-stress induced trehalose accumulation and control of trehalase in the cyanobacterium Nostoc punctiforme IAM M-15

Water-stress induced trehalose accumulation and control of trehalase in the cyanobacterium Nostoc punctiforme IAM M-15

Na+-dependent K+ Uptake Ktr System from the Cyanobacterium Synechocystis sp. PCC 6803 and Its Role in the Early Phases of Cell Adaptation to Hyperosmotic Shock

Adaptation of biochemical composition and cell size to irradiance in two microalgae: possible ecological implications

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