GABA Accumulation in Response to Different Nitrogenous Compounds in Unicellular Cyanobacterium Synechocystis sp. PCC 6803

Kanwal, Simab; Khetkorn, Wanthanee; Incharoensakdi, Aran

doi:10.1007/s00284-014-0687-4

Cited by 19 publications

(9 citation statements)

References 24 publications

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“…Carbon source and nitrogen source are two essential components for the growth and metabolism of microorganisms. They were proven to induce the expression of some enzymes [29,30] and supposed, in this case, to affect the biotransformation ability of C. sinensis . Hence, we chose some carbon sources and nitrogen sources to investigate their influences on the biotransformation of ginsenoside Rb1.…”

Section: Resultsmentioning

confidence: 99%

Highly Selective Bioconversion of Ginsenoside Rb1 to Compound K by the Mycelium of Cordyceps sinensis under Optimized Conditions

Wang

Yan

et al. 2015

Molecules

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Compound K (CK), a highly active and bioavailable derivative obtained from protopanaxadiol ginsenosides, displays a wide variety of pharmacological properties, especially antitumor activity. However, the inadequacy of natural sources limits its application in the pharmaceutical industry. In this study, we firstly discovered that Cordyceps sinensis was a potent biocatalyst for the biotransformation of ginsenoside Rb1 into CK. After a series of investigations on the biotransformation parameters, an optimal composition of the biotransformation culture was found to be lactose, soybean powder and MgSO4 without controlling the pH. Also, an optimum temperature of 30 °C for the biotransformation process was suggested in a range of 25 °C-50 °C. Then, a biotransformation pathway of Rb1 → Rd → F2 → CK was established using high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). Our results demonstrated that the molar bioconversion rate of Rb1 to CK was more than 82% and the purity of CK produced by C. sinensis under the optimized conditions was more than 91%. In conclusion, the combination of C. sinensis and the optimized conditions is applicable for the industrial preparation of CK for medicinal purposes.

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Section: Resultsmentioning

confidence: 99%

Highly Selective Bioconversion of Ginsenoside Rb1 to Compound K by the Mycelium of Cordyceps sinensis under Optimized Conditions

Wang

Yan

et al. 2015

Molecules

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“…Glutamate was not yet described as compatible solute in cyanobacteria (Klähn and Hagemann 2011) and might act as small storage compound because of the decreased glutamate level at night in all strains. A higher glutamate decarboxylase activity and GABA accumulation was observed for Synechocystis with the addition of glutamate to the medium (Kanwal et al. 2015).…”

Section: Discussionmentioning

confidence: 99%

Day and Night: Metabolic Profiles and Evolutionary Relationships of Six Axenic Non-Marine Cyanobacteria

Will

Henke

Boedeker

et al. 2018

Genome Biology and Evolution

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Cyanobacteria are dominant primary producers of various ecosystems and they colonize marine as well as freshwater and terrestrial habitats. On the basis of their oxygenic photosynthesis they are known to synthesize a high number of secondary metabolites, which makes them promising for biotechnological applications. State-of-the-art sequencing and analytical techniques and the availability of several axenic strains offer new opportunities for the understanding of the hidden metabolic potential of cyanobacteria beyond those of single model organisms. Here, we report comprehensive genomic and metabolic analyses of five non-marine cyanobacteria, that is, Nostoc sp. DSM 107007, Anabaena variabilis DSM 107003, Calothrix desertica DSM 106972, Chroococcidiopsis cubana DSM 107010, Chlorogloeopsis sp. PCC 6912, and the reference strain Synechocystis sp. PCC 6803. Five strains that are prevalently belonging to the order Nostocales represent the phylogenetic depth of clade B1, a morphologically highly diverse sister lineage of clade B2 that includes strain PCC 6803. Genome sequencing, light and scanning electron microscopy revealed the characteristics and axenicity of the analyzed strains. Phylogenetic comparisons showed the limits of the 16S rRNA gene for the classification of cyanobacteria, but documented the applicability of a multilocus sequence alignment analysis based on 43 conserved protein markers. The analysis of metabolites of the core carbon metabolism showed parts of highly conserved metabolic pathways as well as lineage specific pathways such as the glyoxylate shunt, which was acquired by cyanobacteria at least twice via horizontal gene transfer. Major metabolic changes were observed when we compared alterations between day and night samples. Furthermore, our results showed metabolic potential of cyanobacteria beyond Synechocystis sp. PCC 6803 as model organism and may encourage the cyanobacterial community to broaden their research to related organisms with higher metabolic activity in the desired pathways.

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“…PCC 6803 was obtained from the Pasteur culture collection. The Δ gdc mutant was constructed previously 14 by deleting the gdc gene ( sll1641 ) in the WT Synechocystis . Approximately 5% (v/v) of a 14-d-old cell culture was inoculated into BG-11 medium 15 without citrate but supplemented with 20 mM HEPES-NaOH (pH 7.5).…”

Section: Methodsmentioning

confidence: 99%

“…We found that gdc inactivation reduced the metabolites levels in the TCA cycle, but increased the accumulation levels of PHB and pyruvate. Since, gdc inactivation has also been shown to significantly increase the glutamate (Glu) level in Synechocystis 14 , we next asked whether the increased PHB level mediated by gdc inactivation was a consequence from the increased Glu level or from the affected TCA cycle. To address this, a section of the metabolic network that links Glu metabolism, the TCA cycle and PHB synthesis was examined by analyzing relevant metabolites and enzymatic activities.…”

Section: Introductionmentioning

confidence: 99%

Disruption of cyanobacterial γ-aminobutyric acid shunt pathway reduces metabolites levels in tricarboxylic acid cycle, but enhances pyruvate and poly(3-hydroxybutyrate) accumulation

Monshupanee

Chairattanawat

Incharoensakdi

2019

Sci Rep

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The photoautotrophic cyanobacterium Synechocystis sp. PCC 6803 assimilates carbon dioxide as the sole carbon source, and a major portion of the assimilated carbon is metabolically consumed by the tricarboxylic acid (TCA) cycle. Effects of partial interference of TCA cycle metabolic activity on other carbon metabolism have yet to be examined. Here, the γ-aminobutyric acid (GABA) shunt, one of the metabolic pathways for completing TCA cycle in Synechocystis , was disrupted via inactivating the glutamate decarboxylase gene ( gdc ). Under normal photoautotrophic condition, cell growth and the level of the TCA cycle metabolites succinate, malate and citrate were decreased by 25%, 35%, 19% and 28%, respectively, in Δ gdc mutant relative to those in the wild type (WT). The cellular levels of glycogen and total lipids of the Δ gdc mutant were comparable to those of the WT, but the intracellular levels of pyruvate and bioplastic poly(3-hydroxybutyrate) (PHB) were 1.23- and 2.50-fold higher, respectively, in Δ gdc mutant. Thus, disruption of the GABA shunt pathway reduced the TCA cycle metabolites levels, but positively enhanced the bioaccumulation of pyruvate and PHB. The PHB production rate in Δ gdc mutant was 2.0-fold higher than in the WT under normal photoautotrophy.

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GABA Accumulation in Response to Different Nitrogenous Compounds in Unicellular Cyanobacterium Synechocystis sp. PCC 6803

Cited by 19 publications

References 24 publications

Highly Selective Bioconversion of Ginsenoside Rb1 to Compound K by the Mycelium of Cordyceps sinensis under Optimized Conditions

Highly Selective Bioconversion of Ginsenoside Rb1 to Compound K by the Mycelium of Cordyceps sinensis under Optimized Conditions

Day and Night: Metabolic Profiles and Evolutionary Relationships of Six Axenic Non-Marine Cyanobacteria

Disruption of cyanobacterial γ-aminobutyric acid shunt pathway reduces metabolites levels in tricarboxylic acid cycle, but enhances pyruvate and poly(3-hydroxybutyrate) accumulation

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