Tubulin code eraser CCP5 binds branch glutamates by substrate deformation.

Microtubule function is modulated by the tubulin code, diverse posttranslational modifications that are altered dynamically by writer and eraser enzymes1. Glutamylation-the addition of branched (isopeptide-linked) glutamate chains-is the most evolutionarily widespread tubulin modification2. It is introduced by tubulin tyrosine ligase-like enzymes and erased by carboxypeptidases of the cytosolic carboxypeptidase (CCP) family1. Glutamylation homeostasis, achieved through the balance of writers and erasers, is critical for normal cell function3-9, and mutations in CCPs lead to human disease10-13. Here we report cryo-electron microscopy structures of the glutamylation eraser CCP5 in complex with the microtubule, and X-ray structures in complex with transition-state analogues. Combined with NMR analysis, these analyses show that CCP5 deforms the tubulin main chain into a unique turn that enables lock-and-key recognition of the branch glutamate in a cationic pocket that is unique to CCP family proteins. CCP5 binding of the sequences flanking the branch point primarily through peptide backbone atoms enables processing of diverse tubulin isotypes and non-tubulin substrates. Unexpectedly, CCP5 exhibits inefficient processing of an abundant ß-tubulin isotype in the brain. This work provides an atomistic view into glutamate branch recognition and resolution, and sheds light on homeostasis of the tubulin glutamylation syntax.

Precise coordination of high-loading Fe single atoms with sulfur boosts selective generation of nonradicals.

Nonradicals are effective in selectively degrading electron-rich organic contaminants, which unfortunately suffer from unsatisfactory yield and uncontrollable composition due to the competitive generation of radicals. Herein, we precisely construct a local microenvironment of the carbon nitride-supported high-loading (~9 wt.%) Fe single-atom catalyst (Fe SAC) with sulfur via a facile supermolecular self-assembly strategy. Short-distance S coordination boosts the peroxymonosulfate (PMS) activation and selectively generates high-valent iron-oxo species (FeIV=O) along with singlet oxygen (1O2), significantly increasing the 1O2 yield, PMS utilization, and p-chlorophenol reactivity by 6.0, 3.0, and 8.4 times, respectively. The composition of nonradicals is controllable by simply changing the S content. In contrast, long-distance S coordination generates both radicals and nonradicals, and could not promote reactivity. Experimental and theoretical analyses suggest that the short-distance S upshifts the d-band center of the Fe atom, i.e., being close to the Fermi level, which changes the binding mode between the Fe atom and O site of PMS to selectively generate 1O2 and FeIV=O with a high yield. The short-distance S-coordinated Fe SAC exhibits excellent application potential in various water matrices. These findings can guide the rational design of robust SACs toward a selective and controllable generation of nonradicals with high yield and PMS utilization.

Promote electroreduction of CO2 via catalyst valence state manipulation by surface-capping ligand.

Electrochemical CO2 reduction provides a potential means for synthesizing value-added chemicals over the near equilibrium potential regime, i.e., formate production on Pd-based catalysts. However, the activity of Pd catalysts has been largely plagued by the potential-depended deactivation pathways (e.g., [Formula: see text]-PdH to [Formula: see text]-PdH phase transition, CO poisoning), limiting the formate production to a narrow potential window of 0 V to -0.25 V vs. reversible hydrogen electrode (RHE). Herein, we discovered that the Pd surface capped with polyvinylpyrrolidone (PVP) ligand exhibits effective resistance to the potential-depended deactivations and can catalyze formate production at a much extended potential window (beyond -0.7 V vs. RHE) with significantly improved activity (~14-times enhancement at -0.4 V vs. RHE) compared to that of the pristine Pd surface. Combined results from physical and electrochemical characterizations, kinetic analysis, and first-principle simulations suggest that the PVP capping ligand can effectively stabilize the high-valence-state Pd species (Pdδ+) resulted from the catalyst synthesis and pretreatments, and these Pdδ+ species are responsible for the inhibited phase transition from [Formula: see text]-PdH to [Formula: see text]-PdH, and the suppression of CO and H2 formation. The present study confers a desired catalyst design principle, introducing positive charges into Pd-based electrocatalyst to enable efficient and stable CO2 to formate conversion.

A Poly(amino acid)-Based Nanomedicine Strategy: Telomere-Telomerase Axis Targeting and Magnetic Resonance Imaging in Hepatocellular Carcinoma Treatment.

Targeting telomere maintenance has emerged as a promising strategy for hepatocellular carcinoma (HCC) treatment. However, given the duality of the telomere-telomerase axis in telomere maintenance, a comprehensive strategy is urgently needed. Herein, we develop a poly(amino acid) (D-PAAs)-based strategy for spatiotemporal codelivery of telomerase inhibitor, BIBR1523, and AKT inhibitor, isobavachalcone. By leveraging D-PAAs' modifiability, we synthesize polymer-inhibitor conjugates (PB and PI) and a folic acid-decorated tumor-targeting vector (PF). These building blocks undergo micellization to fabricate a codelivery nanomedicine (P-BI@P-FA) by exploiting D-PAAs' noncovalent assembly. P-BI@P-FA improves the pharmacokinetics, tumor selectivity, and bioavailability of small molecule inhibitors and initiates a dual telomere-specific inhibition by combining telomerase deactivation with telomere disruption. Furthermore, a hybrid tumor-targeting magnetic nanosystem is designed using D-PAAs and manganese dioxide to showcase magnetic resonance imaging capacities. Our D-PAAs-based strategy addresses the pressing need for telomere-specific HCC treatment while allowing for diagnostic application, presenting a promising avenue for nanomedicine design.

Association between Homologous Recombination Repair Defect Status and Long-Term Prognosis of Early HER2-Low Breast Cancer: A Retrospective Cohort Study.

BACKGROUND: As a newly identified subtype of HER2-negative tumors associated with a less favorable prognosis, it remains crucial to evaluate potential prognostic and predictive factors, particularly non-invasive biomarkers, for individuals with human epidermal growth factor 2 (HER2) low early-stage breast cancer (EBC). Multiple investigations have highlighted that HER2-negative patients with EBC exhibiting high homologous recombination deficiency (HRD) scores display lower rates of pathological complete response (PCR) to neoadjuvant chemotherapy (NAC). Nevertheless, no study to date has explored the correlation between HRD and the long-term prognosis in HER2-low patients with EBC. PATIENTS AND METHODS: This retrospective observational study focuses on primary EBC sourced from The Cancer Genome Atlas dataset (TCGA). It reveals the gene mutation landscape in EBC with low HER2 expression and elucidates the tumor immune landscape across different HRD states. Utilizing bioinformatics analysis and Cox proportional models, along with the Kaplan-Meier method, the study assesses the correlation between HRD status and disease-specific survival (DSS), disease-free interval (DFI), and progression-free interval (PFI). Subgroup analyses were conducted to identify potential variations in the association between HRD and prognosis. RESULTS: In the patients with HER2-low breast cancer, patients with homologous recombination related genes (HRRGs) defects had an HRD score about twice that of those without related genes mutations, and were at higher risk of acquiring ARID1A, ATM, and BRCA2 mutations. We also found that most immune cell abundances were significantly higher in EBC tumors with high HRD than in EBC tumors with low HRD or HRD-medium, particularly plasma B-cell abundance, CD8 T-cell abundance, and M1 macrophages. In addition, these tumors with HRD-high also appear to have significantly higher tumor immune scores and lower interstitial scores. Then, we analyzed the relationship between different HRD status and prognosis. There was statistical significance (P = .036 and P = .046, respectively) in DSS and PFI between the HRD-low and HRD-high groups, and patients with HRD-high EBC showed relatively poor survival outcomes. A medium HRD score (hazard ratio, HR = 2.15, 95% CI: 1.04-4.41, P = .038) was a significant risk factor for PFI. Hormone receptor positivity is an important factor in obtaining medium-high HRD score and poor prognosis. CONCLUSION: Higher HRD scores were associated with poorer PFI outcomes, particularly in people with HR+/HER2-low. Varied HRD states exhibited distinctions in HRRGs and the tumor immune landscape. These insights have the potential to assist clinicians in promptly identifying high-risk groups and tailoring personalized treatments for patients with HER2-low EBC, aiming to enhance long-term outcomes.

Association of FTH1-Expressing Circulating Tumor Cells With Efficacy of Neoadjuvant Chemotherapy for Patients With Breast Cancer: A Prospective Cohort Study.

BACKGROUND: The association between different phenotypes and genotypes of circulating tumor cells (CTCs) and efficacy of neoadjuvant chemotherapy (NAC) remains uncertain. This study was conducted to evaluate the relationship of FTH1 gene-associated CTCs (F-CTC) with/without epithelial-mesenchymal transition (EMT) markers, or their dynamic changes with the efficacy of NAC in patients with non-metastatic breast cancer. PATIENTS AND METHODS: This study enrolled 120 patients with non-metastatic breast cancer who planned to undergo NAC. The FTH1 gene and EMT markers in CTCs were detected before NAC (T0), after 2 cycles of chemotherapy (T1), and before surgery (T2). The associations of these different types of CTCs with rates of pathological complete response (pCR) and breast-conserving surgery (BCS) were evaluated using the binary logistic regression analysis. RESULTS: F-CTC in peripheral blood ≥1 at T0 was an independent factor for pCR rate in patients with HER2-positive (odds ratio [OR]=0.08, 95% confidence interval [CI], 0.01-0.98, P = .048). The reduction in the number of F-CTC at T2 was an independent factor for BCS rate (OR = 4.54, 95% CI, 1.14-18.08, P = .03). CONCLUSIONS: The number of F-CTC prior to NAC was related to poor response to NAC. Monitoring of F-CTC may help clinicians formulate personalized NAC regimens and implement BCS for patients with non-metastatic breast cancer.

Stable-Isotope N-Me Aziridination Enables Accurate Quantitative C═C Isomeric Lipidomics.

Accurate lipid quantification is essential to revealing their roles in physiological and pathological processes. However, difficulties in the structural resolution of lipid isomers hinder their further accurate quantification. To address this challenge, we developed a novel stable-isotope N-Me aziridination strategy that enables simultaneous qualification and quantification of unsaturated lipid isomers. The one-step introduction of the 1-methylaziridine structure not only serves as an activating group for the C═C bond to facilitate positional identification but also as an isotopic inserter to achieve accurate relative quantification. The high performance of this reaction for the identification of unsaturated lipids was verified by large-scale resolution of the C═C positions of 468 lipids in serum. More importantly, by using this bifunctional duplex labeling method, various unsaturated lipids such as fatty acids, phospholipids, glycerides, and cholesterol ester were accurately and individually quantified at the C═C bond isomeric level during the mouse brain ischemia. This study provides a new approach to quantitative structural lipidomics.

Cytological analysis of flower development, insights into suitable growth area and genomic background: implications for Glehnia littoralis conservation and sustainable utilization.

BACKGROUND: Glehnia littoralis F. Schmidt ex Miq., an endangered plant species with significant medicinal, edible, and ecological value, is now a central concern for conservation and sustainable utilization. Investigating the physiological and ecological mechanisms leading to its endangerment and elucidating its genetic background constitutes the foundation for conducting in-depth research on G. littoralis. RESULTS: Our observations have revealed a significant degree of floral sterility in wild populations of G. littoralis. The inflorescences of G. littoralis are classified into three types: completely fertile, completely sterile, and partially fertile compound umbels. Moreover, the flowers of G. littoralis can be categorized into fertile and sterile types. Sterile flowers exhibited abnormalities in the stigma, ovary, and ovules. This study is the first to discover that the presence or absence of a giant cell at the funiculus during the initiation of ovule primordium determines whether the flower can develop normally, providing cytological evidence for female sterility in G. littoralis. Conversely, both fertile and sterile flowers produced normally developed pollen. Field observations have suggested that robust plants bear more fertile umbels, while weaker ones have fewer or even no fertile umbels, indicating a close relationship between flower fertility and plant nutritional status. Our model correctly predicted that the eastern coastal regions of China, as well as prospective areas in Neimenggu and Sichuan, are suitable environments for its cultivation. Additionally, Using flow cytometry and genome survey, we estimated the genome size of G. littoralis to be 3.06 Gb and the heterozygosity to be 4.58%. CONCLUSION: The observations and findings presented in this study were expected to provide valuable insights for further conserving its genetic resources and sustainable utilization of G. littoralis.

Genome-wide identification and expression analysis of the PP2C gene family in Apocynum venetum and Apocynum hendersonii.

BACKGROUND: Protein phosphatase class 2 C (PP2C) is the largest protein phosphatase family in plants. Members of the PP2C gene family are involved in a variety of physiological pathways in plants, including the abscisic acid signalling pathway, the regulation of plant growth and development, etc., and are capable of responding to a wide range of biotic and abiotic stresses, and play an important role in plant growth, development, and response to stress. Apocynum is a perennial persistent herb, divided into Apocynum venetum and Apocynum hendersonii. It mainly grows in saline soil, deserts and other harsh environments, and is widely used in saline soil improvement, ecological restoration, textiles and medicine. A. hendersonii was found to be more tolerant to adverse conditions. The main purpose of this study was to investigate the PP2C gene family and its expression pattern under salt stress and to identify important candidate genes related to salt tolerance. RESULTS: In this study, 68 AvPP2C genes and 68 AhPP2C genes were identified from the genomes of A. venetum and A. hendersonii, respectively. They were classified into 13 subgroups based on their phylogenetic relationships and were further analyzed for their subcellular locations, gene structures, conserved structural domains, and cis-acting elements. The results of qRT-PCR analyses of seven AvPP2C genes and seven AhPP2C genes proved that they differed significantly in gene expression under salt stress. It has been observed that the PP2C genes in A. venetum and A. hendersonii exhibit different expression patterns. Specifically, AvPP2C2, 6, 24, 27, 41 and AhPP2C2, 6, 24, 27, 42 have shown significant differences in expression under salt stress. This indicates that these genes may play a crucial role in the salt tolerance mechanism of A. venetum and A. hendersonii. CONCLUSIONS: In this study, we conducted a genome-wide analysis of the AvPP2C and AhPP2C gene families in Apocynum, which provided a reference for further understanding the functional characteristics of these genes.

Excessive Tryptophan and Phenylalanine Induced Pancreatic Injury and Glycometabolism Disorder in Grower-finisher Pigs.

BACKGROUND: The increase in circulating insulin levels is associated with the onset of type 2 diabetes (T2D), and the levels of branched-chain amino acids and aromatic amino acids (AAAs) are altered in T2D, but whether AAAs play a role in insulin secretion and signaling remains unclear. OBJECTIVES: This study aimed to investigate the effects of different AAAs on pancreatic function and on the use of insulin in finishing pigs. METHODS: A total of 18 healthy finishing pigs (Large White) with average body weight of 100 ± 1.15 kg were randomly allocated to 3 dietary treatments: Con, a normal diet supplemented with 0.68% alanine; Phe, a normal diet supplemented with 1.26% phenylalanine; and Trp, a normal diet supplemented with 0.78% tryptophan. The 3 diets were isonitrogenous. There were 6 replicates in each group. RESULTS: Herein, we investigated the effects of tryptophan and phenylalanine on pancreatic function and the use of insulin in finishing pigs and found that the addition of tryptophan and phenylalanine aggravated pancreatic fat deposition, increased the relative content of saturated fatty acids, especially palmitate (C16:0) and stearate (C18:0), and the resulting lipid toxicity disrupted pancreatic secretory function. We also found that tryptophan and phenylalanine inhibited the growth and secretion of ß-cells, downregulated the gene expression of the PI3K/Akt pathway in the pancreas and liver, and reduced glucose utilization in the liver. CONCLUSIONS: Using fattening pigs as a model, multiorgan combined analysis of the insulin-secreting organ pancreas and the main insulin-acting organ liver, excessive intake of tryptophan and phenylalanine will aggravate pancreatic damage leading to glucose metabolism disorders, providing new evidence for the occurrence and development of T2D.

Aromatic Amino Acids Promote Lipid Metabolism Disorders by Increasing Hepatic Bile Acid Synthesis.

BACKGROUND: Obesity is a progressive metabolic disease that begins with lipid metabolism disorders. Aromatic amino acids (AAAs), including tryptophan, phenylalanine, and tyrosine, have diverse biological activities as nutrients. However, the underlying mechanisms by which AAAs affect lipid metabolism are unclear. OBJECTIVES: This study was designed to investigate the possible roles and underlying molecular mechanisms of AAA in the pathogenesis of lipid metabolism disorders. METHODS: We added an AAA mixture to the high-fat diet (HFD) of mice. Glucose tolerance test was recorded. Protein expression of hepatic bile acid (BA) synthase and mRNA expression of BA metabolism-related genes were determined. Hepatic BA profiles and gut microbial were also determined in mice. RESULTS: The results showed that AAA significantly increased body weight and white adipose tissue, aggravated liver injury, impaired glucose tolerance and intestinal integrity, and significantly increased hepatic BA synthesis by inhibiting intestinal farnesoid X receptor (FXR). Moreover, AAA increased the content of total BA in the liver and altered the hepatic BA profile, with elevated levels of lithocholic acid, glycochenodeoxycholic acid, and glycoursodeoxycholic acid. AAA markedly increased the levels of proteins involved in BA synthesis (cholesterol 7α-hydroxylase and oxysterol 7α-hydroxylase) and inhibited the intestinal FXR. Gut microbial composition also changed, reducing the abundance of some beneficial bacteria, such as Parvibacter and Lactobacillus. CONCLUSIONS: Under HFD conditions, AAAs stimulate BA synthesis in both the classical and alternative pathways, leading to aggravation of liver injury and fat deposition. Excessive intake of AAA disrupts BA metabolism and contributes to the development of lipid metabolism disorders, suggesting that AAA may be a causative agent of lipid metabolism disorders.

The addition of pembrolizumab to neoadjuvant chemoradiotherapy did not increase the risk of developing postoperative anastomotic leakage for ESCC: an analysis from a prospective cohort.

BACKGROUND: To compare the difference of postoperative anastomotic leakage (AL) rate between neoadjuvant chemoradiotherapy (NCRT) with pembrolizumab and NCRT group, and investigate the risk factors of developing AL for locally advanced esophageal squamous cell cancer (ESCC). MATERIALS AND METHODS: The GF was contoured on the pretreatment planning computed tomography and dosimetric parameters were retrospectively calculated. Univariate and multivariate logistic regression analysis was performed to determine the independent risk predictors for the entire cohort. A nomogram risk prediction model for postoperative AL was established. RESULTS: A total of 160 ESCC patients were included for analysis. Of them, 112 were treated with NCRT with pembrolizumab and 44 patients with NCRT. Seventeen (10.6%) patients experienced postoperative AL with a rate of 10.7% (12/112) in NCRT with pembrolizumab and 11.4% (5/44) in NCRT group. For the entire cohort, mean, D50, Dmax, V5, V10 and V20 GF dose were statistically higher in those with AL (all p < 0.05). Multivariate logistic regression analysis indicated that tumor length (p = 0.012), volume of GF (p = 0.003) and mean dose of GF (p = 0.007) were independently predictors for postoperative AL. Using receiver operating characteristics analysis, the mean dose limit on the GF was defined as 14 Gy. CONCLUSION: Based on our prospective database, no significant difference of developing AL were observed between NCRT with pembrolizumab and NCRT group. We established an individualized nomograms based on mean GF dose combined with clinical indicators to predict AL in the early postoperative period.

A nomogram based on peripheral lymphocyte for predicting 8-year survival in patients with prostate cancer: a single-center study using LASSO-cox regression.

PURPOSE: The purpose of this study was to develop a functional clinical nomogram for predicting 8-year overall survival (OS) of patients with prostate cancer (PCa) primary based on peripheral lymphocyte. PATIENTS AND METHODS: Using data from a single-institutional registry of 94 patients with PCa in China, this study identified and integrated significant prognostic factors for survival to build a nomogram. The discriminative ability was measured by concordance index (C-index) and ROC curves (Receiver Operating Characteristic Curves). And the predictive accuracy was measured by the calibration curves. Decision curve analyses (DCA) was used to measure the clinical usefulness. RESULTS: A total of 94 patients were included for analysis. Five independent prognostic factors were identified by LASSO-Cox regression and incorporated into the nomogram: age, the T stage, the absolute counts of peripheral CD3(+)CD4(+) T lymphocytes, CD3(-)CD16(+)CD56(+) NK cells and CD4(+)/CD8(+) ratio. The area under the curve (AUC) values of the predictive model for 5-, 8-, and 10-year overall survival were 0.81, 0.76, and 0.73, respectively. The calibration curves for probability of 5-,8- and 10-year OS showed optimal agreement between nomogram prediction and actual observation. The stratification into different risk groups allowed significant distinction. DCA indicated the good clinical application value of the model. CONCLUSION: We developed a novel nomogram that enables personalized prediction of OS for patients diagnosed with PCa. This finding revealed a relative in age and survival rate in PCa, and a more favorable prognosis in patients exhibiting higher levels of CD4 + T, CD4+/CD8 + ratio and CD3(-)CD16(+)CD56(+) NK cells specifically. This clinically applicable prognostic model exhibits promising predictive capabilities, offering valuable support to clinicians in informed decision-making process.

Prognostic significance of platelet­to­albumin ratio in patients with nasopharyngeal carcinoma receiving concurrent chemoradiotherapy: a retrospective study of 858 cases.

BACKGROUND: Despite evidence supporting the high correlation of the novel platelet-to-albumin ratio (PAR) with survival in diverse malignancies, its prognostic relevance in nasopharyngeal carcinoma (NPC) remains underexplored. This study aimed to examine the link between PAR and overall survival (OS) in NPC and to establish a predictive model based on this biomarker. METHODS: We retrospectively assembled a cohort consisting of 858 NPC patients who underwent concurrent chemoradiotherapy (CCRT). Utilizing the maximally selected log-rank method, we ascertained the optimal cut-off point for the PAR. Subsequently, univariate and multivariate Cox proportional hazards models were employed to discern factors significantly associated with OS and to construct a predictive nomogram. Further, we subjected the nomogram's predictive accuracy to rigorous independent validation. RESULTS: The discriminative optimal PAR threshold was determined to be 4.47, effectively stratifying NPC patients into two prognostically distinct subgroups (hazard ratio [HR] = 0.53; 95% confidence interval [CI]: 0.28-0.98, P = 0.042). A predictive nomogram was formulated using the results from multivariate analysis, which revealed age greater than 45 years, T stage, N stage, and PAR score as independent predictors of OS. The nomogram demonstrated a commendable predictive capability for OS, with a C-index of 0.69 (95% CI: 0.64-0.75), surpassing the performance of the conventional staging system, which had a C-index of 0.56 (95% CI: 0.65-0.74). CONCLUSIONS: In the context of NPC patients undergoing CCRT, the novel nutritional-inflammatory biomarker PAR emerges as a promising, cost-efficient, easily accessible, non-invasive, and potentially valuable predictor of prognosis. The predictive efficacy of the nomogram incorporating the PAR score exceeded that of the conventional staging approach, thereby indicating its potential as an enhanced prognostic tool in this clinical setting.

ICP-MS based detection method combined with Au NP and Ag NP labeling for bacteremia diagnosis.

Bacteremia, as a serious infectious disease, has an increasing incidence and a high mortality rate. Early diagnosis and early treatment are crucial for improving the cure rate. In this work, we proposed an inductively coupled plasma mass spectrometry (ICP-MS)-based detection method combined with gold nanoparticle (Au NP) and silver nanoparticle (Ag NP) labeling for the simultaneous detection of Salmonella and Escherichia coli (E. coli O157:H7) in human blood samples. Salmonella and E. coli O157:H7 were captured by magnetic beads coupled with anti-8G3 and anti-7C2, and then specifically labeled by Au NP-anti-5H12 and Ag NP-anti-8B1 respectively, which were used as signal probes for ICP-MS detection. Under the optimal experimental conditions, the limits of detection of 164 CFU mL-1 for Salmonella, 220 CFU mL-1for E. coli O157:H7 and the linear ranges of 400-80,000 CFU mL-1Salmonella, 400-60,000 CFU mL-1 E. coli O157:H7 were obtained. The proposed method can realize the simultaneous detection of two types of pathogenic bacteria in human whole blood in 3.5 h, showing great potential for the rapid diagnosis of bacteremia in clinic.

Electroosmotic Sensing of Uncharged Peptides and Differentiating Their Phosphorylated States Using Nanopores.

The correct characterization and identification of different kinds of proteins is crucial for the survival and development of living organisms, and proteomics research promotes the analysis and understanding of future genome functions. Nanopore technique has been proved to accurately identify individual nucleotides. However, accurate and rapid protein sequencing is difficult due to the variability of protein structures that contains more than 20 amino acids, and it remains very challenging especially for uncharged peptides as they can not be electrophoretically driven through the nanopore. Graphene nanopores have the advantages of high accuracy, sensitivity and low cost in identifying protein phosphorylation modifications. Here, by using all-atom molecular dynamics simulations, charged graphene nanopores are employed to electroosmotically capture and sense uncharged peptides. By further mimicking AFM manipulation of single molecules, it is also found that the uncharged peptides and their phosphorylated states could also be differentiated by both the ionic current and pulling force signals during their pulling processes through the nanopore with a slow and constant velocity. The results shows ability of using nanopores to detect and discriminate single amino acid and its phosphorylation, which is essential for the future low-cost and high-throughput sequencing of protein residues and their post-translational modifications.

Protein Deceleration and Sequencing Using Si3N4-CNT Hybrid Nanopores.

Protein sequencing is crucial for understanding the complex mechanisms driving biological functions and is of utmost importance in molecular diagnostics and medication development. Nanopores have become an effective tool for single molecule sensing, however, the weak charge and non-uniform charge distribution of protein make capturing and sensing very challenging, which poses a significant obstacle to the development of nanopore-based protein sequencing. In this study, to facilitate capturing of the unfolded protein, highly charged peptide was employed in our simulations, we found that the velocity of unfolded peptide translocating through a hybrid nanopore composed of silicon nitride membrane and carbon nanotube is much slower compared to bare silicon nitride nanopore, it is due to the significant interaction between amino acids and the surface of carbon nanotube. Moreover, by introducing variations in the charge states at the boundaries of carbon nanotube nanopores, the competition and combination of the electrophoretic and electroosmotic flows through the nanopores could be controlled, we then successfully regulated the translocation velocity of unfolded proteins through the hybrid nanopores. The proposed hybrid nanopore effectively retards the translocation velocity of protein through it, facilitates the acquisition of ample information for accurate amino acid identification.

Hydroxypropyl Cellulose-Based Orally Dissolving Film Loaded with Insoluble Dexamethasone for Treatment of Oral Ulcers.

Oral ulcers present as recurrent and spontaneous lesions, often causing intolerable burning pain that significantly disrupts patients' daily lives and compromises their quality of life. In addressing this clinical challenge, oral dissolving films (ODFs) have emerged as promising pharmaceutical formulations for oral ulcer management due to their rapid onset of action, ease of administration, and portability. In this study, ODFs containing the insoluble drug dexamethasone (Dex) were formulated for the treatment of oral ulcers in rabbits using a solvent casting method with ethanol as the solvent. To optimize the composition of the ODFs, a Box-Behnken Design (BBD) experiment was employed to investigate the effects of varying concentrations of hydroxypropyl cellulose (HPC), low-substituted hydroxypropyl cellulose (L-HPC), and plasticizer (glycerol) on key parameters, such as disintegration time, tensile strength, and peel-off efficiency of the films. Subsequently, the film properties of the Dex-loaded ODFs (ODF@Dex) were thoroughly assessed, revealing favorable attributes, including homogeneity, mechanical strength, and solubility. Notably, the use of ethanol as the solvent in the ODF preparation facilitated the homogeneous distribution of insoluble drugs within the film matrix, thereby enhancing their solubility and dissolution rate. Leveraging the potent pharmacological activity of Dex, ODF@Dex was further evaluated for its efficacy in promoting ulcer healing and mitigating the expression of inflammatory factors both in vitro and in vivo. The findings demonstrated that the ODF@Dex exerted significant antiulcer effects by modulating the PI3K/Akt signaling pathway, thus contributing to ulcer resolution. In conclusion, our study underscores the potential of HPC-based ODFs formulated with ethanol as a solvent as a promising platform for delivering insoluble drugs, offering a viable strategy for the clinical management of oral ulcers.

Correction: ARGONAUTE10 promotes the degradation of miR165/6 through the SDN1 and SDN2 exonucleases in Arabidopsis.

[This corrects the article DOI: 10.1371/journal.pbio.2001272.].

Trivalent Organostibines: Sb,N Ligands in Double N-Arylation of Primary Amines toward Functionalized Carbazoles.

A Sb,N ligand (L-Sb) for Pd-catalyzed double N-arylation of primary amines was developed. This trivalent ligand L-Sb, containing a 5,6,7,12-tetrahydrodibenzo[c,f][1,5]azastibocine skeleton and stable under air and moisture, could be synthesized facilely on a gram scale from chlorostibine (1) and cyclopentylmagnesium bromide. L-Sb showed excellent catalytic performance in Pd2(dba)3-catalyzed double N-arylation of 2,2'-dibromo-1,1'-biphenyl (2) with primary amines (3), affording functionalized carbazoles in good yields. This Pd2(dba)3/L-Sb-catalyzed double N-arylation, the first example of the application of trivalent organostibines as a ligand in N-arylation, featured the following advantages: small catalyst loading, wide functional group tolerance, good yields, and ease of gram-scale synthesis.