Regulation by external pH and stationary growth phase of the acetolactate synthase from <i>Synechocystis</i> PCC6803

Maestri, Odile; Joset, F.

doi:10.1046/j.1365-2958.2000.02048.x

Cited by 28 publications

(23 citation statements)

References 48 publications

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“…5a). Amiloride is a Na + channel-blocker that has been associated with the blockage of Na + channels utilized in the maintenance of pH and Na + homeostasis in eukaryotes (Schaefer et al, 2001) and prokaryotes (Rowbury et al, 1994), including the cyanobacterium Synechocystis PCC 7120 (Maestri & Joset, 2000). Furthermore, here we documented that the accumulation of STX itself is dependent upon alkaline pH (Fig.…”

supporting

confidence: 65%

Interactions between intracellular Na+ levels and saxitoxin production in Cylindrospermopsis raciborskii T3

et al. 2004

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Saxitoxin (STX) is the most potent representative among the paralytic shellfish poisoning (PSP) toxins, which are highly selective Na + channel-blocking alkaloids. This study investigated, in cultures of the cyanobacterium Cylindrospermopsis raciborskii T3, the effects of pH, salt, amiloride and lidocaine hydrochloride on total cellular levels of Na + and K + ions and STX accumulation. Both Na + levels and intracellular STX concentrations increased exponentially in response to rising alkalinity. NaCl inhibited cyanobacterial growth at a concentration of 10 mM. In comparison with osmotically stressed controls, however, NaCl promoted STX accumulation in a dose-dependent manner. A correlation was seen in the time-course of both total cellular Na + levels and intracellular STX for NaCl, amiloride and lidocaine exposure. The increase in cellular Na + induced by NaCl at 10 mM was coupled with a proportional accumulation of STX. The two Na + channel-blocking agents amiloride and lidocaine had opposing effects on both cellular Na + levels and STX accumulation. Amiloride at 1 mM reduced ion and toxin concentrations, while lidocaine at 1 mM increased the total cellular Na + and STX levels. The effects of the channel-blockers were antagonistic and dependent on an alkaline pH. The results presented suggest that, in C. raciborskii T3, STX is responsive to cellular Na + levels. This may indicate that either STX metabolism or the toxin itself could be linked to the maintenance of cyanobacterial homeostasis. The results also enhance the understanding of STX production and the ecology of PSP toxin-producing cyanobacteria.

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confidence: 65%

Interactions between intracellular Na+ levels and saxitoxin production in Cylindrospermopsis raciborskii T3

et al. 2004

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“…Previously, Sll1981 of Synechocystis sp. PCC 6803 was putatively assigned as a bifunctional enzyme with conserved domains for both acetolactate synthase (ALS) activities 48 and L-myo-inositol 1-phosphate synthase (MIPS). 49 Nevertheless, our enzymatic analysis showed that Sll1981 and Slr0370 functioned as OGDC and SSADH, respectively.…”

Section: Promoter Screening For Higher Ethylene Productivitymentioning

confidence: 99%

Enhancing photosynthetic production of ethylene in genetically engineered Synechocystis sp. PCC 6803

Zhu

Xie

et al. 2015

Green Chem.

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Ethylene is widely used in the petrochemical industry and has traditionally been produced via the steam cracking of petroleum-based feedstock. The exploration of sustainable and carbon-neutral methods of producing ethylene from the renewable feedstock seems promising. The direct photosynthetic production of ethylene after the recycling of carbon dioxide shows great potential. In this study, continuous and stable ethylene production was achieved in Synechocystis sp. PCC 6803 by introducing a codonoptimized ethylene-forming enzyme (EFE) from Pseudomonas syringae pv. sesami and using 2-oxoglutarate (2-OG) as the substrate. Based on diverse promoter screening, PcpcB was proved to be a highly efficient promoter for ethylene production in cyanobacteria. The genes encoding 2-OG decarboxylase (OGDC) and succinic semialdehyde dehydrogenase (SSADH) in the tricarboxylic acid (TCA) cycle in Synechocystis sp. PCC 6803 were identified, and the TCA cycle was genetically modified by blocking these two enzymes with the simultaneous overexpression of EFE. Meanwhile, a gene encoding 2-OG permease (KgtP) from E. coli was introduced into the phaAB loci to increase the 2-OG supply. A peak volumetric production rate of 9.7 mL L −1 h −1 for ethylene was eventually achieved in the Synechocystis recombinant (XX110), with the genetic modification of the TCA cycle and heterologous expression of 2-oxoglutarate permease by the modified semi-continuous cultivation.

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“…In addition, Synechocystis sp. strain PCC 6803 accumulates acetolactate under alkaline conditions, and it has been suggested that this is a mechanism for pH homeostasis (28).…”

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confidence: 99%

Global Transcriptional Response of the Alkali-Tolerant CyanobacteriumSynechocystissp. Strain PCC 6803 to a pH 10 Environment

Summerfield

Sherman

2008

Appl Environ Microbiol

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Many cyanobacterial strains are able to grow at a pH range from neutral to pH 10 or 11. Such alkaline conditions favor cyanobacterial growth (e.g., bloom formation), and cyanobacteria must have developed strategies to adjust to changes in CO 2 concentration and ion availability. Synechocystis sp. strain PCC 6803 exhibits similar photoautotrophic growth characteristics at pH 10 and pH 7.5, and we examined global gene expression following transfer from pH 7.5 to pH 10 to determine cellular adaptations at an elevated pH. The strategies used to develop homeostasis at alkaline pH had elements similar to those of many bacteria, as well as components unique to phototrophic microbes. Some of the response mechanisms previously identified in other bacteria included upregulation of Na ؉ /H ؉ antiporters, deaminases, and ATP synthase. In addition, upregulated genes encoded transporters with the potential to contribute to osmotic, pH, and ion homeostasis (e.g., a water channel protein, a large-conductance mechanosensitive channel, a putative anion efflux transporter, a hexose/proton symporter, and ABC transporters of unidentified substrates). Transcriptional changes specific to photosynthetic microbes involved NADH dehydrogenases and CO 2 fixation. The pH transition altered the CO 2 /HCO 3 ؊ ratio within the cell, and the upregulation of three inducible bicarbonate transporters (BCT1, SbtA, and NDH-1S) likely reflected a response to this perturbed ratio. Consistent with this was increased transcript abundance of genes encoding carboxysome structural proteins and carbonic anhydrase. Interestingly, the transition to pH 10 resulted in increased abundance of transcripts of photosystem II genes encoding extrinsic and low-molecular-weight polypeptides, although there was little change in photosystem I gene transcripts.

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Regulation by external pH and stationary growth phase of the acetolactate synthase from Synechocystis PCC6803

Cited by 28 publications

References 48 publications

Interactions between intracellular Na+ levels and saxitoxin production in Cylindrospermopsis raciborskii T3

Interactions between intracellular Na+ levels and saxitoxin production in Cylindrospermopsis raciborskii T3

Enhancing photosynthetic production of ethylene in genetically engineered Synechocystis sp. PCC 6803

Global Transcriptional Response of the Alkali-Tolerant CyanobacteriumSynechocystissp. Strain PCC 6803 to a pH 10 Environment

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