Development and validation of a prognostic score to identify the optimal candidate for preemptive TIPS in patients with cirrhosis and acute variceal bleeding.

BACKGROUND AND AIM: Baveno VII workshop recommends the use of preemptive TIPS (p-TIPS) in patients with cirrhosis and acute variceal bleeding (AVB) at high- risk of treatment failure. However, the criteria defining "high-risk" have low clinical accessibility or include subjective variables. We aimed to develop and externally validate a model for better identification of p-TIPS candidates. APPROACH AND RESULTS: The derivation cohort included 1554 patients with cirrhosis and AVB who were treated with endoscopy plus drug (n = 1264) or p-TIPS (n = 290) from 12 hospitals in China between 2010 and 2017. We first used competing risk regression to develop a score for predicting 6-week and 1-year mortality in patients treated with endoscopy plus drugs, which included age, albumin, bilirubin, international normalized ratio, white blood cell, creatinine, and sodium. The score was internally validated with the bootstrap method, which showed good discrimination (6 wk/1 y concordance-index: 0.766/0.740) and calibration, and outperformed other currently available models. In the second stage, the developed score was combined with treatment and their interaction term to predicate the treatment effect of p-TIPS (mortality risk difference between treatment groups) in the whole derivation cohort. The estimated treatment effect of p-TIPS varied substantially among patients. The prediction model had good discriminative ability (6 wk/1 y c -for-benefit: 0.696/0.665) and was well calibrated. These results were confirmed in the validation dataset of 445 patients with cirrhosis with AVB from 6 hospitals in China between 2017 and 2019 (6-wk/1-y c-for-benefit: 0.675/0.672). CONCLUSIONS: We developed and validated a clinical prediction model that can help to identify individuals who will benefit from p-TIPS, which may guide clinical decision-making.

Design, synthesis, and biological antitumor evaluation of tetrahydroisoquinoline derivatives.

Cancer, as a public health issue, is the leading cause of death worldwide. Tetrahydroisoquinoline derivatives have effective biological activities and can be used as potential therapeutic agents for antitumor drugs. In this work, we designed and synthesized a series of novel tetrahydroisoquinoline compounds and evaluated their antitumor activity in vitro on several representative human cancer cell lines. The results showed that the vast majority of compounds showed good inhibitory activities against the cancer cell lines of HCT116, MDA-MB-231, HepG2, and A375.

Self-assembled ordered AuNRs-modified electrodes for simultaneous determination of dopamine and topotecan with improved data reproducibility.

Gold nanomaterials have been widely explored in electrochemical sensors due to their high catalytic property and good stability in multi-medium. In this paper, the reproducibility of the signal among batches of gold nanorods (AuNRs)-modified electrodes was investigated to improve the data stabilization and repeatability. Ordered and random self-assembled AuNRs-modified electrodes were used as electrochemical sensors for the simultaneous determination of dopamine (DA) and topotecan (TPC), with the aim of obtaining an improved signal stability in batches of electrodes and realizing the simultaneous determination of both substances. The morphology and structure of the assemblies were analyzed and characterized by UV-Vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). Electrochemical studies showed that the ordered AuNRs/ITO electrodes have excellent signal reproducibility among several individuals due to the homogeneous mass transfer in the ordered arrangement of the AuNRs. Under the optimized conditions, the simultaneous detection results of DA and TPC showed good linearity in the ranges 1.75-45 µM and 1.5-40 µM, and the detection limits of DA and TPC were 0.06 µM and 0.17 µM, respectively. The results showed that the prepared ordered AuNR/ITO electrode had high sensitivity, long-term stability, and reproducibility for the simultaneous determination of DA and TPC, and it was expected to be applicable for real sample testing.

N-Heterocyclic carbene-catalyzed enantioselective annulation of 2-amino-1H-indoles and bromoenals for the synthesis of chiral 2-aryl-2,3-dihydropyrimido[1,2-a]indol-4 (1H)-ones.

An efficient N-heterocyclic carbene (NHC)-catalyzed enantioselective [3 + 3] annulation of 2-bromoenals with 2-amino-1H-indoles has been developed. A series of functionalized 2-aryl-2,3-dihydropyrimido[1,2-a]indol-4(1H)-ones were synthesized using NHCs as the catalyst in good yields with high to excellent enantioselectivities.

Sarcopenia Defined by Psoas Muscle Thickness Predicts Mortality After Transjugular Intrahepatic Portosystemic Shunt.

PURPOSE: To assess and compare the value of psoas muscle thickness at the level of the third lumbar (L3) vertebra (TPML) or umbilicus (TPMU) and skeletal muscle index (SMI) for diagnosing sarcopenia and predicting mortality in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: Two hundred forty-nine patients undergoing TIPS were included in this retrospective study. The cut-offs of L3-SMI for sarcopenia were 42.0 cm2/m2 in men and 38.0 cm2/m2 in women. The cut-offs for TPML/height and TPMU/height to predict mortality was established using a receiver-operating characteristic analysis. The Kaplan-Meier and Cox regression were used for survival analyses. RESULTS: Compared with TPMU/height, TPML/height was more consistent with L3-SM for the diagnosis of sarcopenia (Kappa coefficient: 0.63 vs. 0.36 in men; 0.61 vs. 0.45 in women). The Cox analysis showed that both TPML/height and TPMU/height were independent risk factors for mortality. The optimal cut-off values of TPML/height and TPMU/height for mortality in men and women were 11.2 mm/m, 9.4 mm/m, 18.4 mm/m, 15.1 mm/m, respectively. There were 119 (47.8%), 87 (34.9%), and 82 (32.9%) patients diagnosed with sarcopenia in the TPMU/height, TPML/height, and L3-SMI models, respectively. Kaplan-Meier analysis showed that the overall survival was significantly lower in the sarcopenia group in all three models. CONCLUSION: TPMU/height and TPML/height have a similar survival prognostic value as L3-SMI. TPML/height has better consistency with L3-SMI in diagnosing sarcopenia and is a more stable alternative to L3-SMI for diagnosing sarcopenia in patients undergoing TIPS.

A Novel Evaluation Method for SLAM-Based 3D Reconstruction of Lumen Panoramas.

Laparoscopy is employed in conventional minimally invasive surgery to inspect internal cavities by viewing two-dimensional images on a monitor. This method has a limited field of view and provides insufficient information for surgeons, increasing surgical complexity. Utilizing simultaneous localization and mapping (SLAM) technology to reconstruct laparoscopic scenes can offer more comprehensive and intuitive visual feedback. Moreover, the precision of the reconstructed models is a crucial factor for further applications of surgical assistance systems. However, challenges such as data scarcity and scale uncertainty hinder effective assessment of the accuracy of endoscopic monocular SLAM reconstructions. Therefore, this paper proposes a technique that incorporates existing knowledge from calibration objects to supplement metric information and resolve scale ambiguity issues, and it quantifies the endoscopic reconstruction accuracy based on local alignment metrics. The experimental results demonstrate that the reconstructed models restore realistic scales and enable error analysis for laparoscopic SLAM reconstruction systems. This suggests that for the evaluation of monocular SLAM three-dimensional (3D) reconstruction accuracy in minimally invasive surgery scenarios, our proposed scheme for recovering scale factors is viable, and our evaluation outcomes can serve as criteria for measuring reconstruction precision.

Risk Stratification Based on Chronic Liver Failure Consortium Acute Decompensation Score in Patients With Child-Pugh B Cirrhosis and Acute Variceal Bleeding.

BACKGROUND AND AIMS: Optimal candidates for early transjugular intrahepatic portosystemic shunt (TIPS) in patients with Child-Pugh B cirrhosis and acute variceal bleeding (AVB) remain unclear. This study aimed to test the hypothesis that risk stratification using the Chronic Liver Failure Consortium Acute Decompensation score (CLIF-C ADs) may be useful to identify a subgroup at high risk of mortality or further bleeding that may benefit from early TIPS in patients with Child-Pugh B cirrhosis and AVB. APPROACH AND RESULTS: We analyzed the pooled individual data from two previous studies of 608 patients with Child-Pugh B cirrhosis and AVB who received standard treatment between 2010 and 2017 in China. The concordance index values of CLIF-C ADs for 6-week and 1-year mortality (0.715 and 0.708) were significantly better than those of active bleeding at endoscopy (0.633 [P < 0.001] and 0.556 [P < 0.001]) and other prognostic models. With X-tile software identifying an optimal cutoff value, patients were categorized as low risk (CLIF-C ADs <48), intermediate risk (CLIF-C ADs 48-56), and high risk (CLIF-C ADs >56), with a 5.6%, 16.8%, and 25.4% risk of 6-week death, respectively. Nevertheless, the performance of CLIF-C ADs for predicting a composite endpoint of 6-week death or further bleeding was not satisfactory (area under the receiver operating characteristics curve [AUC], 0.588). A nomogram incorporating components of CLIF-C ADs and albumin, platelet, active bleeding, and ascites significantly improved the prediction accuracy (AUC, 0.725). CONCLUSIONS: In patients with Child-Pugh B cirrhosis and AVB, risk stratification using CLIF-C ADs identifies a subgroup with high risk of death that may derive survival benefit from early TIPS. With improved prediction accuracy for 6-week death or further bleeding, the data-driven nomogram may help to stratify patients in randomized trials. Future external validation of these findings in patients with different etiologies is required.

Effect of polyaspartic acid on soil water storage, soil microbial diversity, cotton yield and fiber quality.

Water-saving is one of the most important problems in agricultural development, especially in arid and semi-arid areas. The effects of polyaspartic acid (PASP) on soil water storage, soil microbial community, soil physiochemical properties, cotton yield and fiber quality were studied to find water-saving material utilized in cotton field. The experiment was divided into two parts, the first part concerned the direct application of three different amounts of PASP under field conditions. In the second part, PASP was mixed with soil in different proportions and the mixtures were put into bottles, which were then buried in the cotton field. The application of PASP improved the water-holding capacity and thus increased water content available to the cotton root system in the cotton field for a long time, and significantly (p < 0.05) increased the content of soil organic matter, available P and ammonium-N. Relative abundances of Methylophaga, Sphingomonas, Cupriavidus, Pseudeurotium, Fusarium and Nectria were significantly affected by applying PASP. Compared to the control group, 15, 75 and 150 kg ha-1 of PASP increased seed cotton yield by 3.94, 8.31 and 7.71%, respectively. The application of PASP also increased the reflectance degree, Micronaire and short fiber index of cotton. These results suggested that 75 kg ha-1 of PASP can be appropriate to alleviate drought stress in arid and semi-arid areas.

Emergent Transjugular Intrahepatic Portosystemic Shunt Creation for Acute Gastric Variceal Bleeding in Patients with Hepatocellular Carcinoma.

A total of 42 cirrhotic patients (mean age, 51.7 years ± 10.8; 38 men) with hepatocellular carcinoma who underwent emergent transjugular intrahepatic portosystemic shunt (TIPS) creation for controlling acute gastric variceal bleeding (GVB) were included in this multicenter retrospective study. Of these, 37 (88.1%) patients underwent emergent TIPS creation as the first-line treatment to control acute GVB. Five (11.9%) patients underwent emergent TIPS creation as a rescue/salvage treatment to control acute GVB after emergent endoscopic therapy and pharmacotherapy. Emergent TIPS creation was technically successful in 40 (95.2%) patients. Two (4.8%) patients had severe and moderate procedural adverse events. The median follow-up duration was 16.9 months (range, 0.1-100.8 months). Failure to control acute bleeding and failure to prevent rebleeding occurred in 8 (19.0%) patients during follow-up. Eighteen (42.9%) patients died during follow-up. Three (7.1%) patients had shunt dysfunction during follow-up. Overt hepatic encephalopathy occurred in 6 (14.3%) patients during follow-up.

Integrated Physiological, Transcriptomic, and Metabolomic Analyses of the Response of Peach to Nitrogen Levels during Different Growth Stages.

This study performed physiological, transcriptome, and metabolite analyses of peach fruit under different nitrogen (N) conditions at different growth stages. Nitrogen management directly affected the yield, fruit quality, and metabolites of peach in different growth stages. Different fertilizing time influenced yield and leaf N concentration. RNA-Seq was used to analyze the influence of N levels at the fruit pit hardening (PH) and fruit expansion (FE) stages. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed differentially expressed genes (DEGs) related to carbon and nitrogen metabolite processes. Metabolome analysis shows that applying different nitrogen fertilizers at different growth stages of peach mainly affected metabolites related to carbon and amino acids. This research provides insight into the metabolic processes underlying different N responses during different growth stages and provides a foundation to improve the efficiency of N use in peach.

[Analysis of IQSEC2 gene variant in a child with X-linked mental retardation].

OBJECTIVE: To analyze the clinical phenotype and genetic variants of a child with X-linked mental retardation caused by IQSEC2 gene mutation, and provide reference for the diagnosis of the disease. METHODS: The child was subjected to next generation sequencing (NGS), and the diagnosis was made by taking consideration of her clinical characteristics. RESULTS: The child has presented with global developmental delay, particularly in fine motor skill and language development, in addition with intellectual disability. Genetic testing revealed that she has harbored a heterozygous c.1861dup variant of the IQSEC2 gene, which was not detected in either parent. CONCLUSION: The de novo c.186ldup variant of the IQSEC2 gene probably underlay the X-linked mental retardation in this child. Above finding has, expanded the spectrum of IQSEC2 gene mutations and provide a basis for the diagnosis of similar cases.

Dysregulation of Wnt/ß-catenin signaling by protein kinases in hepatocellular carcinoma and its therapeutic application.

Wnt/ß-catenin signaling is indispensable for many biological processes, including embryonic development, cell cycle, inflammation, and carcinogenesis. Aberrant activation of the Wnt/ß-catenin signaling can promote tumorigenicity and enhance metastatic potential in hepatocellular carcinoma (HCC). Targeting this pathway is a new opportunity for precise medicine for HCC. However, inhibiting Wnt/ß-catenin signaling alone is unlikely to significantly improve HCC patient outcome due to the lack of specific inhibitors and the complexity of this pathway. Combination with other therapies will be an important next step in improving the efficacy of Wnt/ß-catenin signaling inhibitors. Protein kinases play a key and evolutionarily conserved role in the Wnt/ß-catenin signaling and have become one of the most important drug targets in cancer. Targeting Wnt/ß-catenin signaling and its regulatory kinase together will be a promising HCC management strategy. In this review, we summarize the kinases that modulate the Wnt/ß-catenin signaling in HCC and briefly discuss their molecular mechanisms. Furthermore, we list some small molecules that target the kinases and may inhibit Wnt/ß-catenin signaling, to offer new perspectives for preclinical and clinical HCC studies.

A 1.7-Mb chromosomal inversion downstream of a PpOFP1 gene is responsible for flat fruit shape in peach.

Flat peaches have become popular worldwide due to their novelty and convenience. The peach flat fruit trait is genetically controlled by a single gene at the S locus, but its genetic basis remains unclear. Here, we report a 1.7-Mb chromosomal inversion downstream of a candidate gene encoding OVATE Family Protein, designated PpOFP1, as the causal mutation for the peach flat fruit trait. Genotyping of 727 peach cultivars revealed an occurrence of this large inversion in flat peaches, but absent in round peaches. Ectopic overexpression of PpOFP1 resulted in oval-shaped leaves and shortened siliques in Arabidopsis, suggesting its role in repressing cell elongation. Transcriptional activation of PpOFP1 by the chromosomal inversion may repress vertical elongation in flat-shaped fruits at early stages of development, resulting in the flat fruit shape. Moreover, PpOFP1 can interact with fruit elongation activator PpTRM17, suggesting a regulatory network controlling fruit shape in peach. Additionally, screening of peach wild relatives revealed an exclusive presence of the chromosomal inversion in P. ferganensis, supporting that this species is the ancestor of the domesticated peach. This study provides new insights into mechanisms underlying fruit shape evolution and molecular tools for genetic improvement of fruit shape trait in peach breeding programmes.

Design of a high-resolution holographic waveguide eye-tracking system operating in near-infrared with conventional optical elements.

The eye-tracking system plays an essential role in the augmented reality (AR) eyewear. Waveguide volume holographic optical elements (HOE) that can be made with high efficiency, thin form, and lightweight are well-suited for this application. Traditional holographic lenses formed with spherical wavefronts at visible wavelengths and used for near-infrared (NIR) eye-tracking systems suffer from significant image aberrations, image tilt, and ghost images. This work describes a complete holographic lens design methodology that systematically addresses these issues and details the specifications of conventional optical elements that provide the optimized wavefronts for the hologram construction beams. The resulting waveguide HOE NIR eye-tracking system has an image resolution of ∼10 lp/mm when the designed holographic lens is deposited on a waveguide with a refractive index of 1.8 and thickness of 0.5 mm.

Depicting the composition of gut microbiota in children with tic disorders: an exploratory study.

BACKGROUND: Symptom improvement in children with tic disorder (TD) following fecal microbiota transplantation led us to investigate the gut microbiota in TD. This exploratory study aims to depict the gut microbial profile in patients with TD and explore the impact of dopamine receptor antagonist (DRA) drugs on the composition and metabolic function of the gut microbiota. METHODS: The gut microbiota were profiled in fecal samples of 49 children with TD and 50 matched healthy controls (HC) using shotgun metagenomic sequencing. A random forest (RF) model was constructed using the gut bacterial species to distinguish TD from HC. Associations between clinical metadata and microbial abundance or function were analyzed using MaAsLin2 and Spearman correlation. RESULTS: The gut microbiota in children with TD was featured by higher abundances of Bacteroides plebeius and Ruminococcus lactaris (a potential pro-inflammatory taxon) and lower abundances of Prevotella stercorea and Streptococcus lutetiensis compared to HC. The constructed RF model accurately distinguished TD from HC based on the gut microbiota profile, resulting in an AUC of 0.884. Significant correlations were observed between tic symptom severity and the abundances of multiple bacterial species and gut microbiota metabolic functions. Multivariate analysis identified an upregulation of 4-aminobutanoate (GABA) degradation in the gut microbiota associated with TD status. The gut microbiota of DRA-treated TD children showed a distinct gut microbiota compared to the treatment-naïve group, represented by an increase in some potential enteric pathogens such as Escherichia coli, a decline in several species including Akkermansia muciniphila, and alterations in various metabolic functions. CONCLUSIONS: Bacterial species promoting inflammatory responses and those modulating neurotransmitters such as GABA may be involved in the pathogenesis of TD. The use of DRA drugs is likely to induce overgrowth of some enteric pathogens and alter the gut microbiota metabolism.

Transjugular Intrahepatic Portosystemic Shunt Creation for the Prevention of Gastric Variceal Rebleeding in Patients with Hepatocellular Carcinoma: A Multicenter Retrospective Study.

PURPOSE: To evaluate the effectiveness and safety of transjugular intrahepatic portosystemic shunt (TIPS) creation for the prevention of gastric variceal rebleeding in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: This multicenter retrospective study included 126 cirrhotic patients (mean age, 54.1 ± 10.2 years; 110 men) with HCC who underwent TIPS creation for the prevention of gastric variceal rebleeding. Of these, 110 (87.3%) patients had gastroesophageal varices and 16 (12.7%) patients had isolated gastric varices. Thirty-five (27.8%) patients had portal vein tumor thrombus. RESULTS: TIPS creation was technically successful in 124 (98.4%) patients. Rebleeding occurred in 26 (20.6%) patients during the follow-up period. The 6-week and 1-year actuarial probabilities of patients remaining free of rebleeding were 98.3% ± 1.2% and 81.2% ± 3.9%, respectively. Forty-nine (38.8%) patients died during the follow-up period. The 6-week and 1-year actuarial probabilities of survival were 98.4 ± 1.1% and 65.6 ± 4.4%, respectively. Two (1.6%) patients had major procedure-related complications, including acute liver failure (n = 1) and intra-abdominal bleeding (n = 1). Thirty-three (26.2%) patients had at least 1 episode of overt hepatic encephalopathy during the follow-up period. Shunt dysfunction occurred in 15 (11.9%) patients after a median follow-up time of 11.4 months (range, 1.4-41.3 months). Lung metastasis occurred in 3 (2.4%) patients, 3.9-32.9 months after TIPS creation. CONCLUSIONS: TIPS creation may be effective and safe for the prevention of gastric variceal rebleeding in patients with HCC.

Identifying optimal candidates for early TIPS among patients with cirrhosis and acute variceal bleeding: a multicentre observational study.

OBJECTIVES: Early placement of transjugular intrahepatic portosystemic shunt (TIPS) has been shown to improve survival in high-risk patients (Child-Pugh B plus active bleeding at endoscopy or Child-Pugh C 10-13) with cirrhosis and acute variceal bleeding (AVB). However, early TIPS criteria may overestimate the mortality risk in a significant proportion of patients, and the survival benefit conferred by early TIPS in such patients has been questioned. Alternative criteria have been proposed to refine the criteria used to identify candidates for early TIPS. Nevertheless, the true survival benefit provided (or not) by early TIPS compared with standard treatment in the different risk categories has not been investigated in specifically designed comparative studies. DESIGN: We collected data on 1425 consecutive patients with cirrhosis and AVB who were admitted to 12 university hospitals in China between December 2010 and June 2016. Of these, 206 patients received early TIPS, and 1219 patients received standard treatment. The Fine and Gray competing risk regression model was used to compare the outcomes between the two groups that were stratified based on the currently available risk stratification systems after adjusting for liver disease severity and other potential confounders. RESULTS: Overall, early TIPS was associated with an 80% relative risk reduction (RRR) in mortality at 6 weeks (adjusted HR=0.20; 95% CI: 0.10 to 044; p<0.001) and 51% RRR at 1 year (adjusted HR=0.49, 95% CI: 0.32 to 0.73; p<0.001) compared with standard treatment. In stratification analyses, the RRRs in mortality did not significantly differ among the risk categories. However, the absolute risk reductions (ARRs) of mortality were more pronounced in high-risk patients. The ARRs at 6 weeks were -2.1%, -10.2% and -32.4% in Model for End-stage Liver Disease (MELD) ≤11, 12-18 and ≥19 patients and were -1.5%, -9.1% and -23.2% in Child-Pugh A, B and C patients, respectively (interaction tests, p<0.001 for both criteria). The ARRs for mortality at 1 year were -1.7%, -5.4% and -32.7% in MELD ≤11, 12-18 and ≥19 patients, respectively, and -3.6%, -5.2% and -20.3% in Child-Pugh A, B and C patients, respectively (interaction tests, p<0.001 for both criteria). After adjusting for liver disease severity and other potential confounders, a survival benefit was observed in MELD ≥19 or Child-Pugh C patients but not in MELD ≤11 or Child-Pugh A patients. In MELD 12-18 patients, a survival benefit was observed within 6 weeks but not at 1 year. In Child-Pugh B patients, a survival benefit was observed in those with active bleeding but not those without active bleeding. However, the evaluation of active bleeding was associated with a high interobserver variability. Furthermore, early TIPS was associated with a significantly reduced incidence of failure to control bleeding or rebleeding and new or worsening ascites, without increasing the risk of overt hepatic encephalopathy. CONCLUSIONS: Early TIPS was associated with improved survival in patients with MELD ≥19 or Child-Pugh C cirrhosis but not in patients with MELD ≤11 or Child-Pugh A cirrhosis. For MELD 12-18 or Child-Pugh B patients, future studies addressing optimal selection criteria for early TIPS remain highly warranted.

Activator-type R2R3-MYB genes induce a repressor-type R2R3-MYB gene to balance anthocyanin and proanthocyanidin accumulation.

Anthocyanin and proanthocyanidin (PA) accumulation is regulated by both myeloblastosis (MYB) activators and repressors, but little information is available on hierarchical interactions between the positive and negative regulators. Here, we report on a R2R3-MYB repressor in peach, designated PpMYB18, which acts as a negative regulator of anthocyanin and PA accumulation. PpMYB18 can be activated by both anthocyanin- and PA-related MYB activators, and is expressed both at fruit ripening and juvenile stages when anthocyanins or PAs, respectively, are being synthesized. The PpMYB18 protein competes with MYB activators for binding to basic Helix Loop Helixes (bHLHs), which develops a fine-tuning regulatory loop to balance PA and anthocyanin accumulation. In addition, the bHLH binding motif in the R3 domain and the C1 and C2 repression motifs in the C-terminus of PpMYB18 both confer repressive activity of PpMYB18. Our study also demonstrates a modifying negative feedback loop, which prevents cells from excess accumulation of anthocyanin and PAs, and serves as a model for balancing secondary metabolite accumulation at the transcriptional level.

Enantioselective Mannich Reactions of 3-Fluorooxindoles with Cyclic N-Sulfamidate Aldimines.

Both the 3-fluorooxindole and cyclic sulfamidate frameworks are important in medicinal chemistry owing to their associated biological activities. We report an approach accessing 3-fully substituted 3-fluorooxindoles, containing a benzo-fused sulfamidate subunit through highly enantioselective Mannich-type reactions between 3-fluorooxindoles and cyclic benzo-fused N-sulfamidate aldimines. These reactions are promoted by a commercially available cinchona alkaloid catalyst, accommodate a broad substrate scope, and deliver the desired products in a yield of up to 99% with an enantiomeric excess of up to 94%. A plausible reaction pathway is also presented.

Two amino acid changes in the R3 repeat cause functional divergence of two clustered MYB10 genes in peach.

R2R3-MYB genes play a pivotal role in regulating anthocyanin accumulation. Here, we report two tandemly duplicated R2R3-MYB genes in peach, PpMYB10.1 and PpMYB10.2, with the latter showing lower ability to induce anthocyanin accumulation than the former. Site-directed mutation assay revealed two amino acid changes in the R3 repeat, Arg/Lys66 and Gly/Arg93, responsible for functional divergence between these two PpMYB10 genes. Anthocyanin-promoting activity of PpMYB10.2 was significantly increased by a single amino acid replacement of Arg93 with Gly93. However, either the Gly93 → Arg93 or Arg66 → Lys66 substitutions alone showed little impact on anthocyanin-promoting activity of PpMYB10.1, but simultaneous substitutions caused a significant decrease. Reciprocal substitution of Arg/Gly93 could significantly alter binding affinity to PpbHLH3, while the Arg66 → Lys66 substitution is predicted to affect the folding of the MYB DNA-binding domain, instead of PpbHLH3-binding affinity. Overall, the change of anthocyanin-promoting activity was accompanied with that of bHLH-binding affinity, suggesting that DNA-binding affinity of R2R3-MYBs depends on their bHLH partners. Our study is helpful for understanding of functional evolution of R2R3-MYBs and their interaction with DNA targets.