TOR promotes guard cell starch degradation by regulating the activity of ß-AMYLASE1 in Arabidopsis.

Starch is the main energy storage carbohydrate in plants and serves as an essential carbon storage molecule for plant metabolism and growth under changing environmental conditions. The TARGET of RAPAMYCIN (TOR) kinase is an evolutionarily conserved master regulator that integrates energy, nutrient, hormone, and stress signaling to regulate growth in all eukaryotes. Here, we demonstrate that TOR promotes guard cell starch degradation and induces stomatal opening in Arabidopsis thaliana. Starvation caused by plants growing under short photoperiod or low light photon irradiance, as well as inactivation of TOR, impaired guard cell starch degradation and stomatal opening. Sugar and TOR induce the accumulation of ß-AMYLASE1 (BAM1), which is responsible for starch degradation in guard cells. The plant steroid hormone brassinosteroid and transcription factor BRASSINAZOLE-RESISTANT1 play crucial roles in sugar-promoted expression of BAM1. Furthermore, sugar supply induced BAM1 accumulation, but TOR inactivation led to BAM1 degradation, and the effects of TOR inactivation on BAM1 degradation were abolished by the inhibition of autophagy and proteasome pathways or by phospho-mimicking mutation of BAM1 at serine-31. Such regulation of BAM1 activity by sugar-TOR signaling allows carbon availability to regulate guard cell starch metabolism and stomatal movement, ensuring optimal photosynthesis efficiency of plants.

Dual Channel H2O2 Photosynthesis in Pure Water over S-Scheme Heterojunction Cs3PMo12/CC Boosted by Proton and Electron Reservoirs.

Dual channel photo-driven H2O2 production in pure water on small-scale on-site setups is a promising strategy to provide low-concentrated H2O2 whenever needed. This process suffers, however, strongly from the fast recombination of photo-generated charge carriers and the sluggish oxidation process. Here, insoluble Keggin-type cesium phosphomolybdate Cs3PMo12O40 (abbreviated to Cs3PMo12) is introduced to carbonized cellulose (CC) to construct S-scheme heterojunction Cs3PMo12/CC. Dual channel H2O2 photosynthesis from both H2O oxidation and O2 reduction in pure water has been thus achieved with the production rate of 20.1 mmol L-1 gcat. -1 h-1, apparent quantum yield (AQY) of 2.1% and solar-to-chemical conversion (SCC) efficiency of 0.050%. H2O2 accumulative concentration reaches 4.9 mmol L-1. This high photocatalytic activity is guaranteed by unique features of Cs3PMo12/CC, namely, S-scheme heterojunction, electron reservoir, and proton reservoir. The former two enhance the separation of photo-generated charge carriers, while the latter speeds up the torpid oxidation process. In situ experiments reveal that H2O2 is formed via successive single-electron transfer in both channels. In real practice, exposing the reaction system under natural sunlight outdoors successfully results in 0.24 mmol L-1 H2O2. This work provides a key practical strategy for designing photocatalysts in modulating redox half-reactions in photosynthesis.

Brassinosteroid and Hydrogen Peroxide Interdependently Induce Stomatal Opening by Promoting Guard Cell Starch Degradation.

Starch is the major storage carbohydrate in plants and functions in buffering carbon and energy availability for plant fitness with challenging environmental conditions. The timing and extent of starch degradation appear to be determined by diverse hormonal and environmental signals; however, our understanding of the regulation of starch metabolism is fragmentary. Here, we demonstrate that the phytohormone brassinosteroid (BR) and redox signal hydrogen peroxide (H2O2) induce the breakdown of starch in guard cells, which promotes stomatal opening. The BR-insensitive mutant bri1-116 accumulated high levels of starch in guard cells, impairing stomatal opening in response to light. The gain-of-function mutant bzr1-1D suppressed the starch excess phenotype of bri1-116, thereby promoting stomatal opening. BRASSINAZOLE-RESISTANT1 (BZR1) interacts with the basic leucine zipper transcription factor G-BOX BINDING FACTOR2 (GBF2) to promote the expression of ß-AMYLASE1 (BAM1), which is responsible for starch degradation in guard cells. H2O2 induces BZR1 oxidation, enhancing the interaction between BZR1 and GBF2 to increase BAM1 transcription. Mutations in BAM1 lead to starch accumulation and reduce the effects of BR and H2O2 on stomatal opening. Overall, this study uncovers the critical roles of BR and H2O2 in regulating guard cell starch metabolism and stomatal opening.

An Interpretable Early Dynamic Sequential Predictor for Sepsis-Induced Coagulopathy Progression in the Real-World Using Machine Learning.

Sepsis-associated coagulation dysfunction greatly increases the mortality of sepsis. Irregular clinical time-series data remains a major challenge for AI medical applications. To early detect and manage sepsis-induced coagulopathy (SIC) and sepsis-associated disseminated intravascular coagulation (DIC), we developed an interpretable real-time sequential warning model toward real-world irregular data. Eight machine learning models including novel algorithms were devised to detect SIC and sepsis-associated DIC 8n (1 ≤ n ≤ 6) hours prior to its onset. Models were developed on Xi'an Jiaotong University Medical College (XJTUMC) and verified on Beth Israel Deaconess Medical Center (BIDMC). A total of 12,154 SIC and 7,878 International Society on Thrombosis and Haemostasis (ISTH) overt-DIC labels were annotated according to the SIC and ISTH overt-DIC scoring systems in train set. The area under the receiver operating characteristic curve (AUROC) were used as model evaluation metrics. The eXtreme Gradient Boosting (XGBoost) model can predict SIC and sepsis-associated DIC events up to 48 h earlier with an AUROC of 0.929 and 0.910, respectively, and even reached 0.973 and 0.955 at 8 h earlier, achieving the highest performance to date. The novel ODE-RNN model achieved continuous prediction at arbitrary time points, and with an AUROC of 0.962 and 0.936 for SIC and DIC predicted 8 h earlier, respectively. In conclusion, our model can predict the sepsis-associated SIC and DIC onset up to 48 h in advance, which helps maximize the time window for early management by physicians.

Biodegradation of kraft lignin by newly isolated Klebsiella pneumoniae, Pseudomonas putida, and Ochrobactrum tritici strains.

Bacterial systems have drawn an increasing amount of attention on lignin valorization due to their rapid growth and powerful environmental adaptability. In this study, Klebsiella pneumoniae NX-1, Pseudomonas putida NX-1, and Ochrobactrum tritici NX-1 with ligninolytic potential were isolated from leaf mold samples. Their ligninolytic capabilities were determined by measuring (1) the cell growth on kraft lignin as the sole carbon source, (2) the decolorization of kraft lignin and lignin-mimicking dyes, (3) the micro-morphology changes and transformations of chemical groups in kraft lignin, and (4) the ligninolytic enzyme activities of these three isolates. To the best of our knowledge, this is the first report that Ochrobactrum tritici species can depolymerize and metabolize lignin. Moreover, laccase, lignin peroxidase, and Mn-peroxidase showed high activities in P. putida NX-1. Due to their excellent ligninolytic capabilities, these three bacteria are important supplements to ligninolytic bacteria library and could be valuable in lignin valorization.