Reduction of exogenous ketones depends upon NADPH generated photosynthetically in cells of the cyanobacterium Synechococcus PCC 7942

Yamanaka, Rio; Nakamura, Kaoru; Murakami, Akio

doi:10.1186/2191-0855-1-24

Cited by 18 publications

(10 citation statements)

References 46 publications

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“…To further investigate the effect of K 2 C 2 O 4 on carbon assimilation, leaves were pretreated with iodoacetamide (IAM), an inhibitor of the Calvin cycle [29,30]. In the presence of IAM, no significant differences were observed in F v /F m between K 2 C 2 O 4 treated leaves and control leaves after high light treatment (Figure 9).…”

Section: Resultsmentioning

confidence: 99%

Mechanisms by which the infection of Sclerotinia sclerotiorum (Lib.) de Baryaffects the photosynthetic performance in tobacco leaves

et al. 2014

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BackgroundSclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen which causes disease in a wide range of plants. An observed decrease in photosynthetic performance is the primary reason for the reduction of crop yield induced by S. sclerotiorum. The H2C2O4 is the main pathogenic material secreted by S. sclerotiorum, but the effects of H2C2O4 acidity and the C2O42− ion on photosynthetic performance remain unknown.ResultsS. sclerotiorum infection significantly decreased photosynthetic O2 evolution and the maximum quantum yield of photosystem II (Fv/Fm) in tobacco leaves under high-light. H2C2O4 (the main pathogenic material secreted by S. sclerotiorum) with pH 4.0 also significantly decreased photosynthetic performance. However, treatment with H3PO4 and HCl at the same pH as H2C2O4 caused much less decrease in photosynthetic performance than H2C2O4 did. These results verify that the acidity of the H2C2O4 secreted by S. sclerotiorum was only partially responsible for the observed decreases in photosynthesis. Treatment with 40 mM K2C2O4 decreased Fv/Fm by about 70% of the levels observed under 40 mM H2C2O4, which further demonstrates that C2O42− was the primary factor that impaired photosynthetic performance during S. sclerotiorum infection. K2C2O4 treatment did not further decrease photosynthetic performance when D1 protein synthesis was fully inhibited, indicating that C2O42− inhibited PSII by repressing D1 protein synthesis. It was observed that K2C2O4 treatment inhibited the rate of RuBP regeneration and carboxylation efficiency. In the presence of a carbon assimilation inhibitor, K2C2O42 treatment did not further decrease photosynthetic performance, which infers that C2O42− inhibited PSII activity partly by repressing the carbon assimilation. In addition, it was showed that C2O42− treatment inhibited the PSII activity but not the PSI activity.ConclusionsThis study demonstrated that the damage to the photosynthetic apparatus induced by S. sclerotiorum is not only caused by the acidity of H2C2O4, but also by C2O42− which plays a much more important role in damaging the photosynthetic apparatus. C2O42− inhibits PSII activity, as well as the rate of RuBP regeneration and carboxylation efficiency, leading to the over production of reactive oxygen species (ROS). By inhibiting the synthesis of D1, ROS may further accelerate PSII photoinhibition.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0240-4) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Mechanisms by which the infection of Sclerotinia sclerotiorum (Lib.) de Baryaffects the photosynthetic performance in tobacco leaves

et al. 2014

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“…20 Moreover, literature data indicate that the enzymes involved in such reduction are NAD(P)Hdependent and light is regarded as a crucial regulator of enzyme selectivity in photobiocatalytic reactions. The reduced cofactor, NAD(P)H, generated during photosynthesis, acts as the electron donor, which can be used for the reduction of oxo-xenobiotics to the corresponding chiral alcohols.…”

Section: Resultsmentioning

confidence: 99%

Application of cyanobacteria for chiral phosphonate synthesis

Górak

Żymańczyk–Duda

2015

Green Chem.

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This is the first report on morphologically different strains of cyanobacteria: Arthrospira maxima, Nostoc cf-muscorum and Nodularia sphaerocarpa used for enantioselective bioreduction of selected, structurally different diethyl esters of oxophosphonic acids. The efficiency of the asymmetric hydrogen transfer was strongly dependent on the chemical structure of the substrates. Arthrospira maxima was active only toward diethyl (S)-2-oxopropylphosphonate (20% of yield, 99% of ee), whereas the application of Nostoc cf-muscorum as a biocatalyst allowed diethyl (S)-2-hydroxy-2-phenylethylphosphonate with a high enantiomeric excess (99%) and with 26% conversion degree to be obtained. Employing Nodularia sphaerocarpa led to the most spectacular result -diethyl (S)-2-hydroxy-2-phenylethylphosphonate with a degree of conversion of 99% and an optical purity of 92%. Enantioselective bioconversion of oxophosphonate with an aromatic side group located in the immediate vicinity of the carbonyl functionality was achieved for the first time. Additionally, flow cytometry showed excellent resistance of the cells of Nodularia sphaerocarpa against the examined xenobiotic -2-oxo-2-phenylethylphosphonate, these cells remain viable at the concentration of 10 mM of the bioconversion substrate compared to the 1 mM described previously for a fungal biocatalyst. The effect of cultivation medium, light source and light cycle (light : dark) on the effectiveness of the biotransformation process was examined.

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“…Unicellular strains like Synechocystis and Synechococcus elongatus PCC 7942 (from now on S. elongatus) were intensively studied as host for biotransformations in wild-type cells [19][20][21][22][23][24][25][26][27] and recombinant cells [17,[28][29][30][31][32][33][34][35][36][37]. The ease of handling, well elucidated genetic background, simple morphology, and possible genetic modification made both strains model strains over the years.…”

Section: Methodsmentioning

confidence: 99%

Recent Advances in Cyanobacterial Biotransformations

Malihan‐Yap

Grimm

Kourist

2022

Chemie Ingenieur Technik

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Light-driven biotransformations in recombinant cyanobacteria have been explored in recent years for the production of chiral compounds and platform chemicals. In particular, cyanobacteria harboring oxidoreductases proved to be sustainable hosts providing and recycling reducing equivalents and improving the atom economy of the reactions. However, the provision of light in photobioreactors is considered to be the major bottleneck for up-scaling. In this review, genetic tools for generating recombinant cyanobacterial strains and up to date cyanobacterial biotransformations including redesigning of the photosynthetic electron transport chain to increase specific activities are presented. Finally, several photobioreactor geometries to circumvent the light limitation are discussed and some future perspectives are presented.

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Reduction of exogenous ketones depends upon NADPH generated photosynthetically in cells of the cyanobacterium Synechococcus PCC 7942

Cited by 18 publications

References 46 publications

Mechanisms by which the infection of Sclerotinia sclerotiorum (Lib.) de Baryaffects the photosynthetic performance in tobacco leaves

Mechanisms by which the infection of Sclerotinia sclerotiorum (Lib.) de Baryaffects the photosynthetic performance in tobacco leaves

Application of cyanobacteria for chiral phosphonate synthesis

Recent Advances in Cyanobacterial Biotransformations

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