The challenge of monitoring in planta dynamic changes of NADP(H) and NAD(H) redox states at the subcellular level is considered a major obstacle in plant bioenergetics studies. Here, we introduced two circularly permuted yellow fluorescent protein sensors, iNAP and SoNar, into Arabidopsis thaliana to monitor the dynamic changes in NADPH and the NADH/NAD ratio. In the light, photosynthesis and photorespiration are linked to the redox states of NAD(P)H and NAD(P) pools in several subcellular compartments connected by the malate-OAA shuttles. We show that the photosynthetic increases in stromal NADPH and NADH/NAD ratio, but not ATP, disappear when glycine decarboxylation is inhibited. These observations highlight the complex interplay between chloroplasts and mitochondria during photosynthesis and support the suggestions that, under normal conditions, photorespiration supplies a large amount of NADH to mitochondria, exceeding its NADH-dissipating capacity, and the surplus NADH is exported from the mitochondria to the cytosol through the malate-OAA shuttle.
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http://dx.doi.org/10.1038/s41467-020-17056-0 | DOI Listing |
Arch Microbiol
November 2024
Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
The NADH/NAD balance plays a critical role in regulating cellular and metabolic pathways. In Saccharomyces cerevisiae, glycerol-3-phosphate dehydrogenase (ScGPD) enzymes are essential for NADH homeostasis, glycerol biosynthesis, and osmotic stress adaptation. This study investigates the replacement of ScGPD isoforms with the water-forming NADH oxidase from Lactococcus lactis (LlnoxE) and its effects on 10% glucose fermentation dynamics in minimal medium under microaerobic conditions.
View Article and Find Full Text PDFBiotechnol Bioeng
October 2024
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology (ECUST), Shanghai, People's Republic of China.
While traveling through different zones in large-scale bioreactors, microbes are most likely subjected to fluctuating dissolved oxygen (DO) conditions at the timescales of global circulation time. In this study, to mimic industrial-scale spatial DO gradients, we present a scale-down setup based on dynamic feast/famine regime (150 s) that leads to repetitive cycles with rapid changes in DO availability in glucose-limited chemostat cultures of Penicillium chrysogenum. Such DO feast/famine regime induced a stable and repetitive pattern with a reproducible metabolic response in time, and the dynamic response of intracellular metabolites featured specific differences in terms of both coverage and magnitude in comparison to other dynamic conditions, for example, substrate feast/famine cycles.
View Article and Find Full Text PDFPlant Physiol Biochem
November 2024
School of Biological Sciences, University of Hong Kong, Hong Kong China; HKU Shenzhen Institute of Research and Innovation, Shenzhen, China; State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong China. Electronic address:
Pollen tubes consume a tremendous amount of energy and are the fastest-growing cells known in plants. Mitochondria are key organelles that supply energy and play important roles in modulating cellular redox homeostasis. Here, we found that endogenous NAD(P)H in Arabidopsis pollen tubes was spatially highly correlated with the distribution of mitochondria, both peaking in the subapex region.
View Article and Find Full Text PDFPhytomedicine
October 2024
Research Center for Health and Nutrition, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China. Electronic address:
Background: Drug resistance to doxorubicin (DOX) significantly limits its therapeutic efficacy in breast cancer (BC) patients. Saikosaponin D (SSD), a triterpene saponin derived from the traditional herb Radix Bupleuri, has shown promise as a chemotherapeutic sensitizer in preclinical studies due to its notable antitumor activity. However, the role and mechanism of SSD in DOX-resistant BC cells remain largely unexplored.
View Article and Find Full Text PDFBiotechnol Lett
December 2024
School of Life Sciences, Henan Institute of Science and Technology, 90 Hualan Road, Xinxiang, 453003, Henan, China.
When hypoxanthine was utilized as the activator for the salvage pathway in cAMP synthesis, xanthine oxidase would generate in quantity leading to low hypoxanthine conversion ratios and cell viability. To enhance cAMP salvage synthesis, fermentations with citrate/luteolin and hypoxanthine coupling added were conducted in a 7 L bioreactor and then multiple physiological indicators of fermentation with luteolin addition were assayed. Due to hypoxanthine feeding, cAMP productivity reached 0.
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