Transcriptional and post-transcriptional regulation of chloroplast development by nuclear-localized XAP5 CIRCADIAN TIMEKEEPER.

Chlorophyll biosynthesis and breakdown, important cellular processes for photosynthesis, occur in the chloroplast. As a semi-autonomous organelle, chloroplast development is mainly regulated by nuclear-encoded chloroplast proteins and proteins encoded by itself. However, the knowledge of chloroplast development regulated by other organelles is limited. Here, we report that the nuclear-localized XAP5 CIRCADIAN TIMEKEEPER (XCT) is essential for chloroplast development in Arabidopsis. In this study, significantly decreased chlorophyll content phenotypes of cotyledons and subsequently emerging organs from shoot apical meristem were observed in xct-2. XCT is constitutively expressed in various tissues and localized in the nuclear with speckle patterns. RNA-seq analysis identified 207 differently spliced genes and 1511 differently expressed genes, in which chloroplast development-, chlorophyll metabolism- and photosynthesis-related genes were enriched. Further biochemical assays suggested that XCT was co-purified with the well-known splicing factors and transcription machinery, suggesting dual functions of XCT in gene transcription and splicing. Interestingly, we also found that the chlorophyll contents in xct-2 significantly decreased under high temperature and high light condition, indicating XCT integrates temperature and light signals to fine-tune the chlorophyll metabolism in Arabidopsis. Therefore, our results provide new insights into chloroplast development regulation by XCT, a nuclear-localized protein, at the transcriptional and post-transcriptional level.

Potential use of large language models for mitigating students' problematic social media use: ChatGPT as an example.

The problematic use of social media has numerous negative impacts on individuals' daily lives, interpersonal relationships, physical and mental health, and more. Currently, there are few methods and tools to alleviate problematic social media, and their potential is yet to be fully realized. Emerging large language models (LLMs) are becoming increasingly popular for providing information and assistance to people and are being applied in many aspects of life. In mitigating problematic social media use, LLMs such as ChatGPT can play a positive role by serving as conversational partners and outlets for users, providing personalized information and resources, monitoring and intervening in problematic social media use, and more. In this process, we should recognize both the enormous potential and endless possibilities of LLMs such as ChatGPT, leveraging their advantages to better address problematic social media use, while also acknowledging the limitations and potential pitfalls of ChatGPT technology, such as errors, limitations in issue resolution, privacy and security concerns, and potential overreliance. When we leverage the advantages of LLMs to address issues in social media usage, we must adopt a cautious and ethical approach, being vigilant of the potential adverse effects that LLMs may have in addressing problematic social media use to better harness technology to serve individuals and society.

Decoding the gene regulatory network of endosperm differentiation in maize.

The persistent cereal endosperm constitutes the majority of the grain volume. Dissecting the gene regulatory network underlying cereal endosperm development will facilitate yield and quality improvement of cereal crops. Here, we use single-cell transcriptomics to analyze the developing maize (Zea mays) endosperm during cell differentiation. After obtaining transcriptomic data from 17,022 single cells, we identify 12 cell clusters corresponding to five endosperm cell types and revealing complex transcriptional heterogeneity. We delineate the temporal gene-expression pattern from 6 to 7 days after pollination. We profile the genomic DNA-binding sites of 161 transcription factors differentially expressed between cell clusters and constructed a gene regulatory network by combining the single-cell transcriptomic data with the direct DNA-binding profiles, identifying 181 regulons containing genes encoding transcription factors along with their high-confidence targets, Furthermore, we map the regulons to endosperm cell clusters, identify cell-cluster-specific essential regulators, and experimentally validated three predicted key regulators. This study provides a framework for understanding cereal endosperm development and function at single-cell resolution.

Phytotoxic and Antimicrobial Terrein Derivatives and Butenolides Isolated from the Endophytic Fungus Aspergillus terreus HT5.

Two new terrein derivatives, aspergilethers A and B (1 and 2), two known analogues (3 and 4), and three known butenolides (5-7) were isolated from the endophyte Aspergillus terreus HT5. Their structures were determined by spectroscopic analysis and ECD and NMR calculations. Interestingly, 1 and 2 had unpresented medium aliphatic side chains in terrein derivatives, with different absolute configurations at C-7, which was very scarce. (+)-Terrein (3) exhibited potent postemergence phytotoxicity toward Amaranthaceae, Portulacaceae, and Fabaceae, with MIC values of 250-1000 µg/mL. Transcriptome analysis and qRT-PCR suggested that (+)-terrein induced the transcriptional expression of aging-related genes to accelerate organ senescence and stimulated plant detoxification response. The conjugated system between keto carbonyl and double bonds in the cyclopentenone ring and side chain, and the configurations of C-2 and C-3, played critical roles in the phytotoxicity of terrein derivatives. Meanwhile, 3 was first reported to display moderate antioomycetes activity toward Phytophthora nicotiana.

Enzyme-Silenced Nanosponges Prolong Intratumoral Lifetime to Facilitate Intercellular Relay Drug Delivery and Treatment Efficacy.

The clinical application of nanomedicines faces the dilemma of improved safety but restricted efficacy due to the poor intratumoral bioavailability of chemotherapeutics. We here design an enzyme-silenced nanosponge that shares a long-term lifespan to reversibly exhale/inhale doxorubicin (DOX) for continuous intercellular relay delivery and improved intratumoral retention. The nanosponge is composed of a cationic lipid overlaying a hyaluronic acid derivative polyampholyte core for enveloping of DOX and hyaluronidase-1-targeted siRNA (siHyal1), and a lipoprotein shell decorated with fusion peptide 4F-tLyP-1 that was fused with apolipoprotein A-I (apoA-I) mimetic peptide 4F and tLyP-1 for tumor homing and extravasation into the tumor interstitium. Triggered by the intra/intercellular pH variation, the nanosponge core could reversibly swell in endo/lysosome (pH 5.0) for DOX release. Owing to the deprotonation, the nanosponge core shrinks back in cytoplasm (pH 7.4) for DOX reloading and continues the behavior after being secreted to the extracellular matrix (pH 6.8) via Golgi apparatus, which dramatically improves intratumoral DOX retention and availability. Concurrently, the intratumoral lifespan of the nanosponge is prolonged by siHyal1-specific silencing, ensuring spatiotemporal consistency of carrier and drug when shuttling multilayer tumor cells. As a result, the nanosponge achieves efficient tumor inhibition in 99.1% of tumor spheroids and 80.1% of orthotopic tumor models. Collectively, this study provides an intelligent nanosponge design for active intercellular relay drug delivery, achieving improved intratumoral bioavailability of drugs and amplified chemotherapy on solid tumors.

Development and Evaluation of Polymeric Mixed Micelles Prepared using Hot-Melt Extrusion for Extended Delivery of Poorly Water-Soluble Drugs.

The poor aqueous solubility is a well-recognized restriction for the clinical application of many drug molecules. Micelles delivery system provides a promising strategy for the solubility enhancement of hydrophobic drugs. This study developed and evaluated different polymeric mixed micelles prepared using hot-melt extrusion coupled hydration method to improve the solubility and extend the release of the model drug ibuprofen (IBP). The physicochemical properties of the prepared formulations were characterized in terms of particle size, polydispersity index, zeta potential, surface morphology, crystallinity, encapsulation efficiency, drug content, in vitro drug release, dilution stability, and storage stability. Soluplus®/poloxamer 407, Soluplus®/poloxamer 188, and Soluplus®/TPGS mixed micelles had average particle sizes of 86.2 ± 2.8, 89.6 ± 4.2, and 102.5 ± 3.13 nm, respectively with adequate encapsulation efficiencies of 80% to 92%. Differential scanning calorimetry studies confirmed that the IBP molecules were dissolved in the polymers in an amorphous state. The in vitro release results revealed that the IBP-loaded mixed micelles presented extended-release behavior compared to the free drug. In addition, the developed polymeric mixed micelles remained stable upon dilution and one-month storage. These results demonstrated that the hot-melt extrusion coupling hydration method could be a promising, effective, and environment-friendly manufacturing technique for the scale-up production of polymeric mixed micelles to deliver insoluble drugs.

Immobilization of M3 Muscarinic Receptor to Rapidly Analyze Drug-Protein Interactions and Bioactive Components in a Natural Plant.

Despite its increasing application in pursing potential ligands, the capacity of receptor affinity chromatography is greatly challenged as most current research studies lack a comprehensive characterization of the ligand-receptor interaction, particularly when simultaneously determining their binding thermodynamics and kinetics. This work developed an immobilized M3 muscarinic receptor (M3R) affinity column by fixing M3R on amino polystyrene microspheres via the interaction of a 6-chlorohexanoic acid linker with haloalkane dehalogenase. The efficiency of the immobilized M3R was tested by characterizing the binding thermodynamics and kinetics of three known drugs to immobilized M3R using a frontal analysis and the peak profiling method, as well as by analyzing the bioactive compounds in Daturae Flos (DF) extract. The data showed that the immobilized M3R demonstrated good specificity, stability, and competence for analyzing drug-protein interactions. The association constants of (-)-scopolamine hydrochloride, atropine sulfate, and pilocarpine to M3R were determined to be (2.39 ± 0.03) × 104, (3.71 ± 0.03) × 104, and (2.73 ± 0.04) × 104 M-1, respectively, with dissociation rate constants of 27.47 ± 0.65, 14.28 ± 0.17, and 10.70 ± 0.35 min-1, respectively. Hyoscyamine and scopolamine were verified as the bioactive compounds that bind to M3R in the DF extract. Our results suggest that the immobilized M3R method was capable of determining drug-protein binding parameters and probing specific ligands in a natural plant, thus enhancing the effectiveness of receptor affinity chromatography in diverse stages of drug discovery.

Development of multifunctional drug delivery system via hot-melt extrusion paired with fused deposition modeling 3D printing techniques.

The model of core-shell structured tablets is gaining increased interest due to its advantages in controlled-release and combinational drug delivery. Through the encapsulation of the drug by the outer shell, this model exhibits huge potential for reduced administration frequency, improved taste-masking, and personalized medication strategy. Although different types of core-shell tablets have been recently developed, most of them focused on the embedding of the solid tablets. Therefore there is still a need to investigate an optimized model in which multiple dosage forms can be loaded. This work uses hot-melt extrusion and fused deposition modeling 3D printing (FDM 3DP) techniques to develop a multifunctional core-shell model for controlled drug delivery. Acetaminophen (APAP) was used as the model drug. Hydroxypropyl cellulose (HPC) and hydroxypropyl methylcellulose (HPMC) was used as the matrix materials. Polyethylene oxide (PEO) and Eudragit RS PO (E RSPO) were used to adjust the printability while the E RSPO was expected to act as an extended-release agent due to its hydrophobicity. Liquid, semi-solid and solid dosage forms could be successfully loaded into the produced shells. The formulations were characterized by scanning electron microscopy, three point-bend tests, differential scanning calorimetry, and dissolution studies. The dissolution results suggested the modified-release character of the designed model. Overall, the designed core-shell model could be successfully produced via hot-melt extrusion paired with FDM 3DP techniques and could be utilized for the delivery of distinct dosage forms which improve the on-demand formulation development for patient-centered medication.

Association of Use of Tourniquets During Total Knee Arthroplasty in the Elderly Patients With Post-operative Pain and Return to Function.

Objective: During total knee arthroplasty (TKA), tourniquet may negatively impact post-operative functional recovery. This study aimed at investigating the effects of tourniquet on pain and return to function. Methods: Pubmed, Embase, and Cochrane Library were comprehensively searched for randomized controlled trials (RCTs) published up to February 15th, 2020. Search terms included; total knee arthroplasty, tourniquet, and randomized controlled trial. RCTs evaluating the efficacies of tourniquet during and after operation were selected. Two reviewers independently extracted the data. Effect estimates with 95% CIs were pooled using the random-effects model. Dichotomous data were calculated as relative risks (RR) with 95% confidence intervals (CI). Mean differences (MD) with 95% CI were used to measure the impact of consecutive results. Primary outcomes were the range of motion (ROM) and visual analog scale (VAS) pain scores. Results: Thirty-three RCTs involving a total of 2,393 patients were included in this study. The mean age is 65.58 years old. Compared to no tourniquet group, the use of a tourniquet resulted in suppressed ROM on the 3rd post-operative day [MD, -4.67; (95% CI, -8.00 to -1.35)] and the 1st post-operative month [MD, -3.18; (95% CI, -5.92 to -0.44)]. Pain increased significantly when using tourniquets on the third day after surgery [MD, 0.39; (95% CI, -0.19 to 0.59)]. Moreover, tourniquets can reduce intra-operative blood loss [MD, -127.67; (95% CI, -186.83 to -68.50)], shorter operation time [MD, -3.73; (95% CI, -5.98 to -1.48)], lower transfusion rate [RR, 0.85; (95% CI, 0.73-1.00)], higher superficial wound infection rates RR, 2.43; [(5% CI, 1.04-5.67)] and higher all complication rates [RR, 1.98; (95% CI, 1.22-3.22)]. Conclusion: Moderate certainty evidence shows that the use of a tourniquet was associated with an increased risk of higher superficial wound infection rates and all complication rates. Therefore, the findings did not support the routine use of a tourniquet during TKA.

Multiple fluorescence quenching effects mediated fluorescent sensing of captopril Based on amino Acids-Derivative carbon nanodots.

Carbon nanodots (CNDs) were facilely synthesized through a pyrolysis procedure with histamine, an amino acid rich in element carbon and nitrogen, being the precursor. Taking advantage of the favorable fluorescence performance of CNDs, a multiple fluorescence quenching effects mediated fluorescent sensor was established for captopril (CAP) detection. MnO2 NPs were firstly combined with CNDs via electrostatic attraction and subsequently quenched the fluorescence. The quenching mechanisms were concluded to be the combined effects of fluorescence resonance energy transfer (FRET) and inner filtration effect (IFE). Subsequently CAP triggered a unique redox reaction and decomposed the quencher so that renewed the fluorescence. Hence, the sensitive and selective detection of CAP was achieved through the indication of fluorescence recovery efficiency. A proportional range of 0.4 âˆ¼ 60 µmol L-1 with the LOD of 0.31 µmol L-1 was obtained. The sensor was further applied to the real sample detection and the satisfactory results revealed the practical value of CNDs. The facile synthesis of CNDs and brand-new sensing mechanism made it a novel fluorescent method and could improve the analysis of CAP.

Protective effects and potential mechanism of salvianolic acid B on sodium laurate-induced thromboangiitis obliterans in rats.

BACKGROUND: The root of Salvia miltiorrhiza f. alba (RSMA) (Lamiaceae) is used for the treatment of patients with thromboangiitis obliterans (TAO) in traditional Chinese medicine. Previously, a mixture of phenolic acids extracted from RSMA has shown significant protective effects on TAO rats. PURPOSE: This study investigates the inhibitory effects of salvianolic acid B on TAO induced by sodium laurate injection in rats to explore the effective constituents of RSMA in TAO treatment. METHODS: TAO rats were developed using injected sodium laurate. After treatment with ligustrazine hydrochloride (15 mg/kg) and various doses of salvianolic acid B (10, 20, 40 mg/kg) by tail intravenous injection, levels of thromboxane B2 (TXB2), 6-keto-prostaglandin F1α (6-keto-PGF1α) and endothelin-1 (ET-1) in plasma were determined using enzyme-linked immunosorbent assay. The right femoral arteries were studied by hematoxylin and eosin staining and immunohistochemical analysis to determine pathological changes and overexpression of tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) in the femoral artery walls of TAO rats. RESULTS: Salvianolic acid B significantly decreased the expressions of TXB2 and ET-1 and increased the expression of 6-keto-PGF1α in plasma, and significantly inhibited the overexpression of TNF-α and iNOS in the femoral artery walls of TAO rats at medium and high doses. CONCLUSION: Salvianolic acid B has a protective effect on TAO rats. The mechanism may involve inhibition of thrombosis and TAO-associated inflammatory responses, which may explain the success of RSMA treatment of TAO in humans in traditional Chinese medical practice. Hence, it may be a potential drug for TAO treatment in conventional medicine.

A Sequence-Indexed Mutator Insertional Library for Maize Functional Genomics Study.

Sequence-indexed insertional libraries are important resources for functional gene study in model plants. However, the maize (Zea mays) UniformMu library covers only 36% of the annotated maize genes. Here, we generated a new sequence-indexed maize Mutator insertional library named ChinaMu through high-throughput sequencing of enriched Mu-tagged sequences. A total of 2,581 Mu F2 lines were analyzed, and 311,924 nonredundant Mu insertion sites were obtained. Based on experimental validation, ChinaMu contains about 97,000 germinal Mu insertions, about twice as many as UniformMu. About two-thirds (66,565) of the insertions are high-quality germinal insertions (positive rate > 90%), 89.6% of which are located in genic regions. Furthermore, 45.7% (20,244) of the 44,300 annotated maize genes are effectively tagged and about two-thirds (13,425) of these genes harbor multiple insertions. We tested the utility of ChinaMu using pentatricopeptide repeat (PPR) genes. For published PPR genes with defective kernel phenotypes, 17 out of 20 were tagged, 11 of which had the previously reported mutant phenotype. For 16 unstudied PPR genes with both Mu insertions and defective kernel phenotypes, 6 contained insertions that cosegregated with the mutant phenotype. Our sequence-indexed Mu insertional library provides an important resource for functional genomics study in maize.

VEGF silencing inhibits human osteosarcoma angiogenesis and promotes cell apoptosis via PI3K/AKT signaling pathway.

Vascular endothelial growth factor (VEGF) is one of the most potently angiogenic factors which promotes generation of tumor vasculature. VEGF is usually up-regulated in multiple cancers include osteosarcoma and gliomas. To further explore the potential molecular mechanism that inhibits tumor growth induced by interference of VEGF expression, we constructed an Lv-shVEGF vector and assessed the efficiency of VEGF silencing and its influence on U2OS cells. Our data demonstrated that Lv-shVEGF has high inhibition efficiency on VEGF expression, which inhibits proliferation and promotes apoptosis of U2OS cells in vitro. Our results also indicated that inhibition of VEGF expression suppresses osteosarcoma tumor growth in vivo, VEGF inhibition reduces osteosarcoma angiogenesis. We also found that the phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) activation was considerably reduced after osteosarcoma cells were treated with Lv-shVEGF. Taken together, our data demonstrated that VEGF silencing suppresses cells proliferation, promotes cells apoptosis and reduces osteosarcoma angiogenesis through inactivation of PI3K/AKT signaling pathway.

VEGF Silencing Inhibits Human Osteosarcoma Angiogenesis and Promotes Cell Apoptosis via PI3K/AKT Signaling Pathway.

Vascular endothelial growth factor (VEGF) is one of the most effective angiogenic factors that promote generation of tumor vasculature. VEGF is usually up-regulated in multiple cancers including osteosarcoma and glioma. To further explore the potential molecular mechanism that inhibits tumor growth induced by interference of VEGF expression, we constructed a Lv-shVEGF vector and assessed the efficiency of VEGF silencing and its influence in U2OS cells. The data demonstrate that Lv-shVEGF has high inhibition efficiency on VEGF expression, which inhibits proliferation and promotes apoptosis of U2OS cells in vitro. Our results also indicate that inhibition of VEGF expression suppresses osteosarcoma tumor growth in vivo and reduces osteosarcoma angiogenesis. We also found that the activations of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) were considerably reduced after osteosarcoma cells were treated with Lv-shVEGF. Taken together, our data demonstrate that VEGF silencing suppresses cell proliferation, promotes cell apoptosis, and reduces osteosarcoma angiogenesis through inactivation of PI3K/AKT signaling pathway.