The BEL1-like homeodomain protein OsBLH4 regulates rice plant height, grain number, and heading date by repressing the expression of OsGA2ox1.

Gibberellins (GAs) play crucial roles in regulating plant architecture and grain yield of crops. In rice, the inactivation of endogenous bioactive GAs and their precursors by GA 2-oxidases (GA2oxs) regulates stem elongation and reproductive development. However, the regulatory mechanisms of GA2ox gene expression, especially in rice reproductive organs, are unknown. The BEL1-like homeodomain protein OsBLH4, a negative regulatory factor for the rice OsGA2ox1 gene, was identified in this study. Loss of OsBLH4 function results in decreased bioactive GA levels and pleiotropic phenotypes, including reduced plant height, decreased grain number per panicle, and delayed heading date, as also observed in OsGA2ox1-overexpressing plants. Consistent with the mutant phenotype, OsBLH4 was predominantly expressed in shoots and young spikelets; its encoded protein was exclusively localized in the nucleus. Molecular analysis demonstrated that OsBLH4 directly bound to the promoter region of OsGA2ox1 to repress its expression. Genetic assays revealed that OsBLH4 acts upstream of OsGA2ox1 to control rice plant height, grain number, and heading date. Taken together, these results indicate a crucial role for OsBLH4 in regulating rice plant architecture and yield potential via regulation of bioactive GA levels, and provide a potential strategy for genetic improvements of rice.

Sulfur doping-induced morphological and electronic structure modification of polyoxometalate FeWO4 for enhanced removal of organic pollutants from water.

Wolframite (FeWO4), a typical polyoxometalate, serves as an auspicious candidate for heterogeneous catalysts, courtesy of its high chemical stability and electronic properties. However, the electron-deficient surface-active Fe species in FeWO4 are insufficient to cleave H2O2 via Fe redox-mediated Fenton-like catalytic reaction. Herein, we doped Sulfur (S) atom into FeWO4 catalysts to refine the electronic structure of FeWO4 for H2O2 activation and sulfamethoxazole (SMX) degradation. Furthermore, spin-state reconstruction on S-doped FeWO4 was found to effectively refine the electronic structure of Fe in the d orbital, thereby enhancing H2O2 activation. S doping also accelerated electron transfer during the conversion of sulfur species, promoting the cycling of Fe(III) to Fe(II). Consequently, S-doped FeWO4 bolstered the Fenton-like reaction by nearly two orders of magnitude compared to FeWO4. Significantly, the developed S-doped FeWO4 exhibited a remarkable removal efficiency of approximately 100% for SMX within 40 min in real water samples. This underscores its extensive pH adaptability, robust catalytic stability, and leaching resistance. The matrix effects of water constituents on the performance of S-doped FeWO4 were also investigated, and the results showed that a certain amount of Cl-, SO42-, NO3-, HCO3- and PO43- exhibited negligible effects on the degradation of SMX. Theoretical calculations corroborate that the distinctive spin-state reconstruction of Fe center in S-doped FeWO4 is advantageous for H2O2 decomposition. This discovery offers novel mechanistic insight into the enhanced catalytic activity of S doping in Fenton-like reactions and paves the way for expanding the application of FeWO4 in wastewater treatment.

circCDK13-loaded small extracellular vesicles accelerate healing in preclinical diabetic wound models.

Chronic wounds are a major complication in patients with diabetes. Here, we identify a therapeutic circRNA and load it into small extracellular vesicles (sEVs) to treat diabetic wounds in preclinical models. We show that circCDK13 can stimulate the proliferation and migration of human dermal fibroblasts and human epidermal keratinocytes by interacting with insulin-like growth factor 2 mRNA binding protein 3 in an N6-Methyladenosine-dependent manner to enhance CD44 and c-MYC expression. We engineered sEVs that overexpress circCDK13 and show that local subcutaneous injection into male db/db diabetic mouse wounds and wounds of streptozotocin-induced type I male diabetic rats could accelerate wound healing and skin appendage regeneration. Our study demonstrates that the delivery of circCDK13 in sEVs may present an option for diabetic wound treatment.

Theoretical Insights into Enhancing Catalytic Performance of Al-Cu Alloy for CO2 Electroreduction toward Ethene Production.

The understanding of the reaction mechanism of CO2 electroreduction (CO2RR) is essential for the precise design of catalysts for specific products with high selectivity. In this work, combined with the computational hydrogen electrode model and kinetic energy barrier calculations, CO2RR pathways on Cu(100) and Al1Cu3(100) are intensively investigated. The free energy barrier of the rate-determining step of ethylene formation is reduced from 1.08 eV for *CCOH formation on Cu(100) to 0.51 eV for *CH2OCHOH formation on Al1Cu3(100) and enhances the catalytic activity. The reaction free energy of *CO-*CO coupling is remarkably reduced from 0.86 eV on Cu(100) to -0.43 eV on Al1Cu3(100) and the coupling barrier is reduced from 0.97 to 0.37 eV, suppressing the production of gas phase CO and enhancing the production of C2 products. Furthermore, the selectivity toward C-O breaking of *CH2CHOH on Cu(100) and *CH2CH2OH on Al1Cu3(100) ensures high selectivity toward ethene rather than ethanol.

A regulation strategy of self-assembly molecules for achieving efficient inverted perovskite solar cells.

Self-assembled monolayers (SAMs) have been successfully employed to enhance the efficiency of inverted perovskite solar cells (PSCs) and perovskite/silicon tandem solar cells due to their facile low-temperature processing and superior device performance. Nevertheless, depositing uniform and dense SAMs with high surface coverage on metal oxide substrates remains a critical challenge. In this work, we propose a holistic strategy to construct composite hole transport layers (HTLs) by co-adsorbing mixed SAMs (MeO-2PACz and 2PACz) onto the surface of the H2O2-modified NiOx layer. The results demonstrate that the conductivity of the NiOx bulk phase is enhanced due to the H2O2 modification, thereby facilitating carrier transport. Furthermore, the hydroxyl-rich NiOx surface promotes uniform and dense adsorption of mixed SAM molecules while enhancing their anchoring stability. In addition, the energy level alignment at the interface is improved due to the utilization of mixed SAMs in an optimized ratio. Furthermore, the perovskite film crystal growth is facilitated by the uniform and dense composite HTLs. As a result, the power conversion efficiency of PSCs based on composite HTLs is boosted from 22.26% to 23.16%, along with enhanced operational stability. This work highlights the importance of designing and constructing NiOx/SAM composite HTLs as an effective strategy for enhancing both the performance and stability of inverted PSCs.

Ultrasonography is an effective method for evaluating hepatosplenic fungal infections in pediatric onco-hematological patients.

PURPOSE: This prospective study assessed the value of ultrasonography (US) in the evaluation of hepatosplenic fungal infections (HSFI). METHODS: Thirty-two pediatric participants with confirmed onco-hematological diseases and HSFI were included. Lesions in the liver and/or spleen were detected by US, magnetic resonance imaging (MRI), or computed tomography (CT). RESULTS: Of the participants, 11 (34%) had confirmed HSFI, while 21 (66%) had highly suspected HSFI. The US, CT, MRI, and fungal blood cultures demonstrated positive results in 31, 19, 25, and 7 patients, respectively. US had a significantly higher detection rate than CT, MRI, and fungal blood cultures (p < 0.05). The "bull's eye" phenomenon was a distinctive US feature of HSFI. Follow-up examinations indicated that after a mean of 7.7 (1-15) months, liver and/or spleen lesions disappeared in five patients. The lesion was significantly smaller in 10 patients. Residual calcifications were detected in 15 patients. Two patients died. CONCLUSION: Conclusively, the US may substitute for tissue biopsy, other imaging modalities, or fungal blood culture for the confirmation of HSFI, and may guide better antifungal treatment, thus achieving better outcomes.

Determination of twelve neonicotinoid pesticides in chili using an improved QuEChERS method with UPLC-Q-TOF/MS.

In this study, a QuEChERS method based on citrate was developed and utilized for the analysis of twelve neonicotinoid pesticides in fresh red chilies, fresh green chilies, and dried chilies, coupled with ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS). In the sample preparation, acetonitrile containing 1% formic acid was used as the extraction solvent. Anhydrous sodium sulfate replaced the traditional anhydrous magnesium sulfate for water removal, effectively eliminating the issues of salt caking. Graphitized carbon black, octadecyl silica, and primary secondary amine were used as cleaning agents. The method showed good sensitivity, with the limits of quantification below 0.03 mg/kg for fresh chilies and below 0.15 mg/kg for dried chilies. Values of matrix effects ranged from -19.5% to 8.4%, and the recovery was 86.9% - 105.2%. The analytical method provided an effective tool for the high throughput detection of neonicotinoid pesticide residues in multiple chili matrices.

Zeaxanthin dipalmitate-enriched wolfberry extract improves vision in a mouse model of photoreceptor degeneration.

Zeaxanthin dipalmitate (ZD) is a chemical extracted from wolfberry that protects degenerated photoreceptors in mouse retina. However, the pure ZD is expensive and hard to produce. In this study, we developed a method to enrich ZD from wolfberry on a production line and examined whether it may also protect the degenerated mouse retina. The ZD-enriched wolfberry extract (ZDE) was extracted from wolfberry by organic solvent method, and the concentration of ZD was identified by HPLC. The adult C57BL/6 mice were treated with ZDE or solvent by daily gavage for 2 weeks, at the end of the first week the animals were intraperitoneally injected with N-methyl-N-nitrosourea to induce photoreceptor degeneration. Then optomotor, electroretinogram, and immunostaining were used to test the visual behavior, retinal light responses, and structure. The final ZDE product contained ~30mg/g ZD, which was over 9 times higher than that from the dry fruit of wolfberry. Feeding degenerated mice with ZDE significantly improved the survival of photoreceptors, enhanced the retinal light responses and the visual acuity. Therefore, our ZDE product successfully alleviated retinal morphological and functional degeneration in mouse retina, which may provide a basis for further animal studies for possible applying ZDE as a supplement to treat degenerated photoreceptor in the clinic.

Theoretical Investigations of Hydrolysis Mechanisms of N(SiMe3)3.

Tris(trimethylsilyl)amine (N(SiMe3)3) is one of the most important intermediate products in the indirect synthesis of ammonia (NH3) from nitrogen (N2), which could be hydrolyzed to NH3 under mild conditions. Herein, the hydrolysis mechanism of N(SiMe3)3 has been systematically investigated using density functional theory (DFT) with explicit combined implicit water models. Under neutral conditions, the active barrier of the hydrolysis of N(SiMe3)3 is 17.6 kcal mol-1 in water solvent. The attacking of proton to N center and OH group to Si from water is decoupled for the stabilization of OH group by solvent water molecules, which lower the hydrolysis energy barriers. Furthermore, under acid conditions, N(SiMe3)3 is easily coordinated with proton to form [NH(SiMe3)3]+, and the energy barrier of the hydrolysis reaction could be reduced to 11.5 kcal mol-1 of the first stage, making it being promoted according to the chemical equilibrium. Thus, the results provide an explanation for the possible mechanism of the quantitative conversion of N(SiMe3)3 to NH3 under mild conditions. The decoupled hydrolysis mechanism may play important role in other hydrolysis processes.

High-Throughput Computational Screening of Novel Two-Dimensional Covalent Organic Frameworks for Efficient Photocatalytic Overall Water Splitting.

The pursuit of efficient photocatalysts toward photocatalytic water splitting has attracted wide attention. However, the low efficiency of photocatalytic reactions due to the rapid electron-hole recombination and the time-consuming searching process hinder the development of high-performance photocatalysts. Here, we proposed a data-driven screening procedure for covalent organic frameworks (COFs) as overall solar water-splitting photocatalysts. Based on a COF database through assembling different Cores and Linkers, three COFs are predicted to be efficient photocatalysts for overall solar water splitting after high-throughput computational screening. We found that the photogenerated electrons and holes are well separated on single COF photocatalysts without material engineering, and both hydrogen and oxygen evolution reactions can occur spontaneously on the three screened COFs under visible light radiation. This kind of novel COF screened by a data-driven screening procedure offers new perspectives for advancing efficient photocatalysts.

Relationship between syncopal symptoms and head-up tilt test modes.

OBJECTIVE: Head-up tilt test (HUTT) is an important tool in the diagnosis of pediatric vasovagal syncope. This research will explore the relationship between syncopal symptoms and HUTT modes in pediatric vasovagal syncope. METHODS: A retrospective analysis was performed on the clinical data of 2513 children aged 3-18 years, who were diagnosed with vasovagal syncope, from Jan. 2001 to Dec. 2021 due to unexplained syncope or pre-syncope. The average age was 11.76 ± 2.83 years, including 1124 males and 1389 females. The patients were divided into the basic head-up tilt test (BHUT) group (596 patients) and the sublingual nitroglycerine head-up tilt test (SNHUT) group (1917 patients) according to the mode of positive HUTT at the time of confirmed pediatric vasovagal syncope. RESULTS: (1) Baseline characteristics: Age, height, weight, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and composition ratio of syncope at baseline status were higher in the BHUT group than in the SNHUT group (all P < 0.05). (2) Univariate analysis: Age, height, weight, HR, SBP, DBP, and syncope were potential risk factors for BHUT positive (all P < 0.05). (3) Multivariate analysis: syncope was an independent risk factor for BHUT positive, with a probability increase of 121% compared to pre-syncope (P<0.001). CONCLUSION: The probability of BHUT positivity was significantly higher than SNHUT in pediatric vasovagal syncope with previous syncopal episodes.

Effectiveness and safety of Buzzy device in needle-related procedures for children under twelve years of age: A systematic review and meta-analysis.

BACKGROUND: Pain transcends simple physiology, encompassing biological, emotional, psychological, and social facets. Children show pronounced immediate and enduring responses to pain-related procedures. The aim of this meta-analysis is to investigate the efficacy and safety of the Buzzy device for needle-related procedures in children aged twelve years or younger. METHODS: PubMed, Web of Science, and Embase were searched from inception to July 2023. Only randomized controlled trials utilizing the Buzzy device for needle-related procedures in children under twelve years old were included. Two reviewers independently conducted study selection, data extraction, and risk of bias assessment. Random-effects models were utilized, and analyses were performed using mean differences or standardized mean differences as well as risk ratios. RESULTS: A total of 19 studies were included, involving 2846 participants (Buzzy = 1095, Control = 1751). Compared to no intervention, the Buzzy device significantly reduced pain response [self-report SMD = -1.90 (-2.45, -1.36), parental SMD = -3.04 (-4.09, -1.99), observer SMD = -2.88 (-3.75, -2.02)] and anxiety scores [self-report SMD = -1.97 (-3.05, -0.88), parental SMD = -2.01 (-2.93, -1.08), observer SMD = -1.92 (-2.64, -1.19)]. Compared to virtual reality (VR), the Buzzy device reduced self-reported anxiety levels SMD = -0.47 (-0.77, -0.17), and compared to distraction cards, the Buzzy device reduced parental and observer-reported pain [parental SMD = -0.85 (-1.22, -0.48), observer SMD = -0.70 (-1.00, -0.40)] and anxiety [parental SMD = -0.96 (-1.46, -0.47), observer SMD = -0.91 (-1.40, -0.42)]. Subgroup analysis results showed that procedure type, patient age, measurement scales used, and distance of operation were not the reason of heterogeneity. The summarized first puncture attempt success rate did not differ from other interventions. There were no significant adverse events in the included studies. CONCLUSION: The Buzzy device reduces pain and anxiety in children during needle procedures, ensuring success and safety. Additionally, the effectiveness of the Buzzy device in reducing pain during venipuncture is superior when compared to its effectiveness during intramuscular injections.

Development of an Interpretable Deep Learning Model for Pathological Tumor Response Assessment After Neoadjuvant Therapy.

BACKGROUND: Neoadjuvant therapy followed by surgery has become the standard of care for locally advanced esophageal squamous cell carcinoma (ESCC) and accurate pathological response assessment is critical to assess the therapeutic efficacy. However, it can be laborious and inconsistency between different observers may occur. Hence, we aim to develop an interpretable deep-learning model for efficient pathological response assessment following neoadjuvant therapy in ESCC. METHODS: This retrospective study analyzed 337 ESCC resection specimens from 2020-2021 at the Pudong-Branch (Cohort 1) and 114 from 2021-2022 at the Puxi-Branch (External Cohort 2) of Fudan University Shanghai Cancer Center. Whole slide images (WSIs) from these two cohorts were generated using different scanning machines to test the ability of the model in handling color variations. Four pathologists independently assessed the pathological response. The senior pathologists annotated tumor beds and residual tumor percentages on WSIs to determine consensus labels. Furthermore, 1850 image patches were randomly extracted from Cohort 1 WSIs and binarily classified for tumor viability. A deep-learning model employing knowledge distillation was developed to automatically classify positive patches for each WSI and estimate the viable residual tumor percentages. Spatial heatmaps were output for model explanations and visualizations. RESULTS: The approach achieved high concordance with pathologist consensus, with an R^2 of 0.8437, a RAcc_0.1 of 0.7586, a RAcc_0.3 of 0.9885, which were comparable to two senior pathologists (R^2 of 0.9202/0.9619, RAcc_0.1 of 8506/0.9425, RAcc_0.3 of 1.000/1.000) and surpassing two junior pathologists (R^2 of 0.5592/0.5474, RAcc_0.1 of 0.5287/0.5287, RAcc_0.3 of 0.9080/0.9310). Visualizations enabled the localization of residual viable tumor to augment microscopic assessment. CONCLUSION: This work illustrates deep learning's potential for assisting pathological response assessment. Spatial heatmaps and patch examples provide intuitive explanations of model predictions, engendering clinical trust and adoption (Code and data will be available at https://github.com/WinnieLaugh/ESCC_Percentage once the paper has been conditionally accepted). Integrating interpretable computational pathology could help enhance the efficiency and consistency of tumor response assessment and empower precise oncology treatment decisions.

A Porphyrin-Based 3D Metal-Organic Framework Featuring [Cu8Cl6]10+ Cluster Secondary Building Units: Synthesis, Structure Elucidation, Anion Exchange, and Peroxidase-Like Activity.

Herein, we report a rare example of cationic three-dimensional (3D) metal-organic framework (MOF) of [Cu5Cl3(TMPP)]Cl5 ⋅ xSol (denoted as Cu-TMPP; H2TMPP=meso-tetrakis (6-methylpyridin-3-yl) porphyrin; xSol=encapsulated solvates) supported by [Cu8Cl6]10+ cluster secondary building units (SBUs) wherein the eight faces of the Cl--based octahedron are capped by eight Cu2+. Surface-area analysis indicated that Cu-TMPP features a mesoporous structure and its solvate-like Cl- counterions can be exchanged by BF4 -, PF6 -, and NO3 -. The polyvinylpyrrolidone (PVP) coated Cu-TMPP (denoted as Cu-TMPP-PVP) demonstrated good ROS generating ability, producing ⋅OH in the absence of light (peroxidase-like activity) and 1O2 on light irradiation (650 nm; 25 mW cm-2). This work highlights the potential of Cu-TMPP as a functional carrier of anionic guests such as drugs, for the combination therapy of cancer and other diseases.

Fatty Acid Binding Protein 1 is an Independent Prognostic Biomarker for Gallbladder Cancer with Direct Hepatic Invasion.

Background: Direct liver invasion (DI) is a predominant pathway of gallbladder cancer (GBC) metastasis, but the molecular alterations associated with DI remain addressed. This study identified specific genes correlated with DI, which may offer a potential biomarker for the diagnosis and prognosis of advanced GBC. Methods: RNA samples from 3 patients with DI of GBC were used for RNA-seq analysis. Differentially expressed genes and metabolic pathways between primary tumor (T) and DI tissue was used to analyze aberrant gene expressions. Immunohistochemistry (IHC) of fatty acid binding protein 1 (FABP1) in 62 patients with DI was engaged to evaluate its association with clinicopathological characteristics and prognosis. IHC of CD3+ and CD8+ T cells was analyzed for their correlation with FABP1 expression, clinicopathological features and prognosis. Univariate and multivariate Cox hazards regression analyses were performed to identify independent prognostic factors for disease-free survival (DFS) and overall survival (OS). Results: FABP1 mRNA levels were significantly upregulated in DI region compared to T tissue. IHC results showed identical results with elevated FABP1 (p < 0.0001). Expression of FABP1 in DI region was significantly associated with lymph node metastasis (P = 0.028), reduced DFS (P = 0.013) and OS (P = 0.022); in contrast, its expression in T region was not associated with clinicopathological characteristics and prognosis (P > 0.05). The density of CD8+ T cells in DI region with higher FABP1 expression was significantly lower than that with lower FABP1 expression (p = 0.0084). Multivariate analysis unveiled those hepatic metastatic nodules (HR = 3.35, 95%CI: 1.37-8.15, P = 0.008) and FABP1 expression in DI region (HR = 2.01, 95%CI: 1.05-3.88, P = 0.036) were high risk factors for OS, and FABP1(HR = 2.05, 95%CI: 1.04-4.06, P = 0.039) was also a high risk factor for DFS. Conclusions: Elevated expression of FABP1 in DI region serves as a potential prognostic biomarker for advanced GBC with DI.

Predicting the Efficacy of Novel Synthetic Compounds in the Treatment of Osteosarcoma via Anti-Receptor Activator of Nuclear Factor-κB Ligand (RANKL)/Receptor Activator of Nuclear Factor-κB (RANK) Targets.

BACKGROUND: Osteosarcoma (OS) currently demonstrates a rising incidence, ranking as the predominant primary malignant tumor in the adolescent demographic. Notwithstanding this trend, the pharmaceutical landscape lacks therapeutic agents that deliver satisfactory efficacy against OS. OBJECTIVE: This study aimed to authenticate the outcomes of prior research employing the HM and GEP algorithms, endeavoring to expedite the formulation of efficacious therapeutics for osteosarcoma. METHODS: A robust quantitative constitutive relationship model was engineered to prognosticate the IC50 values of innovative synthetic compounds, harnessing the power of gene expression programming. A total of 39 natural products underwent optimization via heuristic methodologies within the CODESSA software, resulting in the establishment of a linear model. Subsequent to this phase, a mere quintet of descriptors was curated for the generation of non-linear models through gene expression programming. RESULTS: The squared correlation coefficients and s2 values derived from the heuristics stood at 0.5516 and 0.0195, respectively. Gene expression programming yielded squared correlation coefficients and mean square errors for the training set at 0.78 and 0.0085, respectively. For the test set, these values were determined to be 0.71 and 0.0121, respectively. The s2 of the heuristics for the training set was discerned to be 0.0085. CONCLUSION: The analytic scrutiny of both algorithms underscores their commendable reliability in forecasting the efficacy of nascent compounds. A juxtaposition based on correlation coefficients elucidates that the GEP algorithm exhibits superior predictive prowess relative to the HM algorithm for novel synthetic compounds.

Deficiency of skeletal muscle Agrin contributes to the pathogenesis of age-related sarcopenia in mice.

Sarcopenia, a progressive and prevalent neuromuscular disorder, is characterized by age-related muscle wasting and weakening. Despite its widespread occurrence, the molecular underpinnings of this disease remain poorly understood. Herein, we report that levels of Agrin, an extracellular matrix (ECM) protein critical for neuromuscular formation, were decreased with age in the skeletal muscles of mice. The conditional loss of Agrin in myogenic progenitors and satellite cells (SCs) (Pax7 Cre:: Agrin flox/flox) causes premature muscle aging, manifesting a distinct sarcopenic phenotype in mice. Conversely, the elevation of a miniaturized form of Agrin in skeletal muscle through adenovirus-mediated gene transfer induces enhanced muscle capacity in aged mice. Mechanistic investigations suggest that Agrin-mediated improvement in muscle function occurs through the stimulation of Yap signaling and the concurrent upregulation of dystroglycan expression. Collectively, our findings underscore the pivotal role of Agrin in the aging process of skeletal muscles and propose Agrin as a potential therapeutic target for addressing sarcopenia.

Deciphering the role of Enterococcus faecium cytidine deaminase in gemcitabine resistance of gallbladder cancer.

Gemcitabine-based chemotherapy is a cornerstone of standard care for gallbladder cancer (GBC) treatment. Still, drug resistance remains a significant challenge, influenced by factors such as tumor-associated microbiota impacting drug concentrations within tumors. Enterococcus faecium, a member of tumor-associated microbiota, was notably enriched in the GBC patient cluster. In this study, we investigated the biochemical characteristics, catalytic activity, and kinetics of the cytidine deaminase of E. faecium (EfCDA). EfCDA showed the ability to convert gemcitabine to its metabolite 2',2'-difluorodeoxyuridine. Both EfCDA and E. faecium can induce gemcitabine resistance in GBC cells. Moreover, we determined the crystal structure of EfCDA, in its apo form and in complex with 2', 2'-difluorodeoxyuridine at high resolution. Mutation of key residues abolished the catalytic activity of EfCDA and reduced the gemcitabine resistance in GBC cells. Our findings provide structural insights into the molecular basis for recognizing gemcitabine metabolite by a bacteria CDA protein and may provide potential strategies to combat cancer drug resistance and improve the efficacy of gemcitabine-based chemotherapy in GBC treatment.

Nonspecific phospholipases C3 and C4 interact with PIN-FORMED2 to regulate growth and tropic responses in Arabidopsis.

The dynamic changes in membrane phospholipids affect membrane biophysical properties and cell signaling, thereby influencing numerous biological processes. Nonspecific phospholipase C (NPC) enzymes hydrolyze common phospholipids to release diacylglycerol (DAG), which is converted to phosphatidic acid (PA) and other lipids. In this study, 2 Arabidopsis (Arabidopsis thaliana) tandemly arrayed genes, NPC3 and NPC4, were identified as critical factors modulating auxin-controlled plant growth and tropic responses. Moreover, NPC3 and NPC4 were shown to interact with the auxin efflux transporter PIN-FORMED2 (PIN2). The loss of NPC3 and NPC4 enhanced the endocytosis and vacuolar degradation of PIN2, which disrupted auxin gradients and slowed gravitropic and halotropic responses. Furthermore, auxin-triggered activation of NPC3 and NPC4 is required for the asymmetric PA distribution that controls PIN2 trafficking dynamics and auxin-dependent tropic responses. Collectively, our study reveals an NPC-derived PA signaling pathway in Arabidopsis auxin fluxes that is essential for fine-tuning the balance between root growth and environmental responses.

Molecular basis of A. thaliana KEOPS complex in biosynthesizing tRNA t6A.

In archaea and eukaryotes, the evolutionarily conserved KEOPS is composed of four core subunits-Kae1, Bud32, Cgi121 and Pcc1, and a fifth Gon7/Pcc2 that is found in fungi and metazoa. KEOPS cooperates with Sua5/YRDC to catalyze the biosynthesis of tRNA N6-threonylcarbamoyladenosine (t6A), an essential modification needed for fitness of cellular organisms. Biochemical and structural characterizations of KEOPSs from archaea, yeast and humans have determined a t6A-catalytic role for Kae1 and auxiliary roles for other subunits. However, the precise molecular workings of KEOPSs still remain poorly understood. Here, we investigated the biochemical functions of A. thaliana KEOPS and determined a cryo-EM structure of A. thaliana KEOPS dimer. We show that A. thaliana KEOPS is composed of KAE1, BUD32, CGI121 and PCC1, which adopts a conserved overall arrangement. PCC1 dimerization leads to a KEOPS dimer that is needed for an active t6A-catalytic KEOPS-tRNA assembly. BUD32 participates in direct binding of tRNA to KEOPS and modulates the t6A-catalytic activity of KEOPS via its C-terminal tail and ATP to ADP hydrolysis. CGI121 promotes the binding of tRNA to KEOPS and potentiates the t6A-catalytic activity of KEOPS. These data and findings provide insights into mechanistic understanding of KEOPS machineries.