Proteomic Profiling of Muscular Adaptations to Short-Term Concentric Versus Eccentric Exercise Training in Humans.

The molecular mechanisms underlying muscular adaptations to concentric (CON) and eccentric (ECC) exercise training have been extensively explored. However, most previous studies have focused on specifically selected proteins, thus, unable to provide a comprehensive protein profile and potentially missing the crucial mechanisms underlying muscular adaptation to exercise training. We herein aimed to investigate proteomic profiles of human skeletal muscle in response to short-term resistance training. Twenty young males were randomly and evenly assigned to two groups to complete a 4-week either ECC or CON training program. Measurements of body composition and physiological function of the quadriceps femoris were conducted both before and after the training. Muscle biopsies from the vastus lateralis of randomly selected participants (five in ECC and four in CON) of both before and after the training were analyzed using the liquid-chromatography tandem mass spectrometry in combination with bioinformatics analysis. Neither group presented a significant difference in body composition or leg muscle mass; however, muscle peak torque, total work, and maximal voluntary contraction were significantly increased after the training in both groups. Proteomics analysis revealed 122 differentially abundant proteins (DAPs; p value < 0.05 & fold change >1.5 or <0.67) in ECC, of which the increased DAPs were mainly related to skeletal muscle contraction and cytoskeleton and enriched specifically in the pentose phosphate pathway, extracellular matrix-receptor interaction, and PI3K-Akt signaling pathway, whereas the decreased DAPs were associated with the mitochondrial respiratory chain. One hundred one DAPs were identified in CON, of which the increased DAPs were primarily involved in translation/protein synthesis and the mitochondria respiratory, whereas the decreased DAPs were related to metabolic processes, cytoskeleton, and de-ubiquitination. In conclusion, the 4-week CON and ECC training resulted in distinctly different proteomic profiles, especially in proteins related to muscular structure and metabolism.

Dynamic genomic changes in methotrexate-resistant human cancer cell lines beyond DHFR amplification suggest potential new targets for preventing drug resistance.

BACKGROUND: Although DHFR gene amplification has long been known as a major mechanism for methotrexate (MTX) resistance in cancer, the early changes and detailed development of the resistance are not yet fully understood. METHODS: We performed genomic, transcriptional and proteomic analyses of human colon cancer cells with sequentially increasing levels of MTX-resistance. RESULTS: The genomic amplification evolved in three phases (pre-amplification, homogenously staining region (HSR) and extrachromosomal DNA (ecDNA)). We confirm that genomic amplification and increased expression of DHFR, with formation of HSRs and especially ecDNAs, is the major driver of resistance. However, DHFR did not play a detectable role in the early phase. In the late phase (ecDNA), increase in FAM151B protein level may also have an important role by decreasing sensitivity to MTX. In addition, although MSH3 and ZFYVE16 may be subject to different posttranscriptional regulations and therefore protein expressions are decreased in ecDNA stages compared to HSR stages, they still play important roles in MTX resistance. CONCLUSION: The study provides a detailed evolutionary trajectory of MTX-resistance and identifies new targets, especially ecDNAs, which could help to prevent drug resistance. It also presents a proof-of-principal approach which could be applied to other cancer drug resistance studies.

Chimeric virus-like particles of human norovirus constructed by structure-guided epitope grafting elicit cross-reactive immunity against both GI.1 and GII.4 genotypes.

IMPORTANCE: Human norovirus (HuNoV) is highly infectious and can result in severe illnesses in the elderly and children. So far, there is no effective antiviral drug to treat HuNoV infection, and thus, the development of HuNoV vaccines is urgent. However, NoV evolves rapidly, and currently, at least 10 genogroups with numerous genotypes have been found. The genetic diversity of NoV and the lack of cross-protection between different genotypes pose challenges to the development of broadly protective vaccines. In this study, guided by structural alignment between GI.1 and GII.4 HuNoV VP1 proteins, several chimeric-type virus-like particles (VLPs) were designed through surface-exposed loop grafting. Mouse immunization studies show that two of the designed chimeric VLPs induced cross-immunity against both GI.1 and GII.4 HuNoVs. To our knowledge, this is the first designed chimeric VLPs that can induce cross-immune activities across different genogroups of HuNoV, which provides valuable strategies for the development of cross-reactive HuNoV vaccines.

Reduction characteristic of chlorobenzene by a newly isolated Paenarthrobacter ureafaciens LY from a pharmaceutical wastewater treatment plant.

A highly efficient chlorobenzene-degrading strain was isolated from the sludge of a sewage treatment plant associated with a pharmaceutical company. The strain exhibited a similarity of over 99.9% with multiple strains of Paenarthrobacter ureafaciens. Therefore, the strain was suggested to be P. ureafaciens LY. This novel strain exhibited a broad spectrum of pollutant degradation capabilities, effectively degrading chlorobenzene and other organic pollutants, such as 1, 2, 4-trichlorobenzene, phenol, and xylene. Moreover, P. ureafaciens LY co-metabolized mixtures of chlorobenzene with 1, 2, 4-trichlorobenzene or phenol. Evaluation of its degradation efficiency showed that it achieved an impressive degradation rate of 94.78% for chlorobenzene within 8 h. The Haldane-Andrews model was used to describe the growth of P. ureafaciens LY under specific pollutants and its concentrations, revealing a maximum specific growth rate (µmax ) of 0.33 h-1 . The isolation and characterization of P. ureafaciens LY, along with its ability to degrade chlorobenzene, provides valuable insights for the development of efficient and eco-friendly approaches to mitigate chlorobenzene contamination. Additionally, investigation of the degradation performance of the strain in the presence of other pollutants offers important information for understanding the complexities of co-metabolism in mixed-pollutant environments.

Moderate-Intensity Treadmill Exercise Regulates GSK3α/ß Activity in the Cortex and Hippocampus of APP/PS1 Transgenic Mice.

BACKGROUND: Physical exercise has been shown to be beneficial for individuals with Alzheimer's disease (AD), although the underlying mechanisms are not fully understood. METHODS: Six-month-old Amyloid precursor protein/Presenilin 1 (APP/PS1) transgenic (Tg) mice and wild-type (Wt) mice were randomly assigned to either a sedentary group (Tg-Sed, Wt-Sed) or an exercise group (Tg-Ex, Wt-Ex) undertaking a 12-week, moderate-intensity treadmill running program. Consequently, all mice were tested for memory function and amyloid ß (Aß) levels and phosphorylation of tau and protein kinase B (Akt)/glycogen synthase kinase-3 (GSK3) were examined in tissues of both the cortex and hippocampus. RESULTS: Tg-Sed mice had severely impaired memory, higher levels of Aß, and increased phosphorylation of tau, GSK3α tyrosine279, and GSK3ß tyrosine216, but less phosphorylation of GSK3α serine21, GSK3ß serine9, and Akt serine473 in both tissues than Wt-Sed mice in respective tissues. Tg-Ex mice showed significant improvement in memory function along with lower levels of Aß and less phosphorylation of tau (both tissues), GSK3α tyrosine279 (both tissues), and GSK3ß tyrosine216 (hippocampus only), but increased phosphorylation of GSK3α serine21 (both tissues), GSK3ß serine9 (hippocampus only), and Akt serine473 (both tissues) compared with Tg-Sed mice in respective tissues. CONCLUSIONS: Moderate-intensity aerobic exercise is highly effective in improving memory function in 9-month-old APP/PS1 mice, most likely through differential modulation of GSK3α/ß phosphorylation in the cortex and hippocampus.

The MocR family transcriptional regulator DnfR has multiple binding sites and regulates Dirammox gene transcription in Alcaligenes faecalis JQ135.

Microbial ammonia oxidation is vital to the nitrogen cycle. A biological process, called Dirammox (direct ammonia oxidation, NH3 →NH2 OH→N2 ), has been recently identified in Alcaligenes ammonioxydans and Alcaligenes faecalis. However, its transcriptional regulatory mechanism has not yet been fully elucidated. The present study characterized a new MocR-like transcription factor DnfR that is involved in the Dirammox process in A. faecalis strain JQ135. The entire dnf cluster was composed of 10 genes and transcribed as five transcriptional units, that is, dnfIH, dnfR, dnfG, dnfABCDE and dnfF. DnfR activates the transcription of dnfIH, dnfG and dnfABCDE genes, and represses its own transcription. The intact 1506-bp dnfR gene was required for activation of Dirammox. Electrophoretic mobility shift assays and DNase I footprinting analyses showed that DnfR has one binding site in the dnfH-dnfR intergenic region and two binding sites in the dnfG-dnfA intergenic region. Three binding sites of DnfR shared a 6-bp repeated conserved sequence 5'-GGTCTG-N17 -GGTCTG-3' which was essential for the transcription of downstream target genes. Cysteine and glutamate act as possible effectors of DnfR to activate the transcription of transcriptional units of dnfG and dnfABCDE, respectively. This study provided new insights in the transcriptional regulation mechanism of Dirammox by DnfR in A. faecalis JQ135.

Evolution of the interactions between GII.4 noroviruses and histo-blood group antigens: Insights from experimental and computational studies.

Norovirus (NoV) is the major pathogen causing the outbreaks of the viral gastroenteritis across the world. Among the various genotypes of NoV, GII.4 is the most predominant over the past decades. GII.4 NoVs interact with the histo-blood group antigens (HBGAs) to invade the host cell, and it is believed that the receptor HBGAs may play important roles in selecting the predominate variants by the nature during the evolution of GII.4 NoVs. However, the evolution-induced changes in the HBGA-binding affinity for the GII.4 NoV variants and the mechanism behind the evolution of the NoV-HBGA interactions remain elusive. In the present work, the virus-like particles (VLPs) of the representative GII.4 NoV stains epidemic in the past decades were expressed by using the Hansenula polymorpha yeast expression platform constructed by our laboratory, and then the enzyme linked immunosorbent assay (ELISA)-based HBGA-binding assays as well as the molecular dynamics (MD) simulations combined with the molecular mechanics/generalized born surface area (MMGBSA) calculations were performed to investigate the interactions between various GII.4 strains and different types of HBGAs. The HBGA-binding assays show that for all the studied types of HBGAs, the evolution of GII.4 NoVs results in the increased NoV-HBGA binding affinities, where the early epidemic strains have the lower binding activity and the newly epidemic strains exhibit relative stronger binding intensity. Based on the MD simulation and MMGBSA calculation results, a physical mechanism that accounts for the increased HBGA-binding affinity was proposed. The evolution-involved residue mutations cause the conformational rearrangements of loop-2 (residues 390-396), which result in the narrowing of the receptor-binding pocket and thus tighten the binding of the receptor HBGAs. Our experimental and computational studies are helpful for better understanding the mechanism behind the evolution-induced increasing of HBGA-binding affinity, which may provide useful information for the drug and vaccine designs against GII.4 NoVs.

JMJD6 protects against isoproterenol-induced cardiac hypertrophy via inhibition of NF-κB activation by demethylating R149 of the p65 subunit.

Histone modification plays an important role in pathological cardiac hypertrophy and heart failure. In this study we investigated the role of a histone arginine demethylase, Jumonji C domain-containing protein 6 (JMJD6) in pathological cardiac hypertrophy. Cardiac hypertrophy was induced in rats by subcutaneous injection of isoproterenol (ISO, 1.2 mg·kg-1·d-1) for a week. At the end of the experiment, the rats underwent echocardiography, followed by euthanasia and heart collection. We found that JMJD6 levels were compensatorily increased in ISO-induced hypertrophic cardiac tissues, but reduced in patients with heart failure with reduced ejection fraction (HFrEF). Furthermore, we demonstrated that JMJD6 overexpression significantly attenuated ISO-induced hypertrophy in neonatal rat cardiomyocytes (NRCMs) evidenced by the decreased cardiomyocyte surface area and hypertrophic genes expression. Cardiac-specific JMJD6 overexpression in rats protected the hearts against ISO-induced cardiac hypertrophy and fibrosis, and rescued cardiac function. Conversely, depletion of JMJD6 by single-guide RNA (sgRNA) exacerbated ISO-induced hypertrophic responses in NRCMs. We revealed that JMJD6 interacted with NF-κB p65 in cytoplasm and reduced nuclear levels of p65 under hypertrophic stimulation in vivo and in vitro. Mechanistically, JMJD6 bound to p65 and demethylated p65 at the R149 residue to inhibit the nuclear translocation of p65, thus inactivating NF-κB signaling and protecting against pathological cardiac hypertrophy. In addition, we found that JMJD6 demethylated histone H3R8, which might be a new histone substrate of JMJD6. These results suggest that JMJD6 may be a potential target for therapeutic interventions in cardiac hypertrophy and heart failure.

Oxidation of organoarsenicals and antimonite by a novel flavin monooxygenase widely present in soil bacteria.

Arsenic can be biomethylated to form a variety of organic arsenicals differing in toxicity and environmental mobility. Trivalent methylarsenite (MAs(III)) produced in the methylation process is more toxic than inorganic arsenite (As(III)). MAs(III) also serves as a primitive antibiotic and, consequently, some environmental microorganisms have evolved mechanisms to detoxify MAs(III). However, the mechanisms of MAs(III) detoxification are not well understood. In this study, we identified an arsenic resistance (ars) operon consisting of three genes, arsRVK, that contribute to MAs(III) resistance in Ensifer adhaerens ST2. ArsV is annotated as an NADPH-dependent flavin monooxygenase with unknown function. Expression of arsV in the arsenic hypersensitive Escherichia coli strain AW3110Δars conferred resistance to MAs(III) and the ability to oxidize MAs(III) to MAs(V). In the presence of NADPH and either FAD or FMN, purified ArsV protein was able to oxidize both MAs(III) to MAs(V) and Sb(III) to Sb(V). Genes with arsV-like sequences are widely present in soils and environmental bacteria. Metagenomic analysis of five paddy soils showed the abundance of arsV-like sequences of 0.12-0.25 ppm. These results demonstrate that ArsV is a novel enzyme for the detoxification of MAs(III) and Sb(III) and the genes encoding ArsV are widely present in soil bacteria.

Genetic Foundations of Direct Ammonia Oxidation (Dirammox) to N2 and MocR-Like Transcriptional Regulator DnfR in Alcaligenes faecalis Strain JQ135.

Ammonia oxidation is an important process in both the natural nitrogen cycle and nitrogen removal from engineered ecosystems. Recently, a new ammonia oxidation pathway termed Dirammox (direct ammonia oxidation, NH3→NH2OH→N2) has been identified in Alcaligenes ammonioxydans. However, whether Dirammox is present in other microbes, as well as its genetic regulation, remains unknown. In this study, it was found that the metabolically versatile bacterium Alcaligenes faecalis strain JQ135 could efficiently convert ammonia into N2 via NH2OH under aerobic conditions. Genetic deletion and complementation results suggest that dnfABC is responsible for the ammonia oxidation to N2 in this strain. Strain JQ135 also employs aerobic denitrification, mainly producing N2O and trace amounts of N2, with nitrite as the sole nitrogen source. Deletion of the nirK and nosZ genes, which are essential for denitrification, did not impair the capability of JQ135 to oxidize ammonia to N2 (i.e., Dirammox is independent of denitrification). Furthermore, it was also demonstrated that pod (which encodes pyruvic oxime dioxygenase) was not involved in Dirammox and that AFA_16745 (which was previously annotated as ammonia monooxygenase and is widespread in heterotrophic bacteria) was not an ammonia monooxygenase. The MocR-family transcriptional regulator DnfR was characterized as an activator of the dnfABC operon with the binding motif 5'-TGGTCTGT-3' in the promoter region. A bioinformatic survey showed that homologs of dnf genes are widely distributed in heterotrophic bacteria. In conclusion, this work demonstrates that, besides A. ammonioxydans, Dirammox occurs in other bacteria and is regulated by the MocR-family transcriptional regulator DnfR. IMPORTANCE Microbial ammonia oxidation is a key and rate-limiting step of the nitrogen cycle. Three previously known ammonia oxidation pathways (i.e., nitrification, anaerobic ammonia oxidation [Anammox], and complete ammonia oxidation [Comammox]) are mediated by autotrophic microbes. However, the genetic foundations of ammonia oxidation by heterotrophic microorganisms have not been investigated in depth. Recently, a previously unknown pathway, termed direct ammonia oxidation to N2 (Dirammox), has been identified in the heterotrophic bacterium Alcaligenes ammonioxydans HO-1. This paper shows that, in the metabolically versatile bacterium Alcaligenes faecalis JQ135, the Dirammox pathway is mediated by dnf genes, which are independent of the denitrification pathway. A bioinformatic survey suggests that homologs of dnf genes are widely distributed in bacteria. These findings enhance the understanding of the molecular mechanisms of heterotrophic ammonia oxidation to N2.

Microcella aerolata sp. nov., isolated from electronic waste-associated bioaerosols.

A Gram-positive, non-motile, non-spore-forming and short rod-shaped actinomycete strain, designated GA224T, was isolated from electronic waste-associated bioaerosols. The optimal growth conditions for this isolate, a facultatively anaerobic bacterium, were 37 °C and pH 8.0. The cell-wall peptidoglycan type was B2γ, with 2,4-diaminobutyric acid (DAB) as the diamino acids, while the major menaquinone was MK-12. The polar lipid profile was composed of diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids, unidentified glycolipids and an unidentified lipid. The major cellular fatty acids were anteiso-C15:0 and iso-C16:0. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GA224T fell within the genus Microcella. The draft genome of strain GA224T comprised 2,495,189 bp with a G + C content of 72.2 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain GA224T and the type strain of the type species of Microcella species were lower than 95% and 70%, respectively. Based on the phenotypic, chemotaxonomic and genomic data, strain GA224T represents a novel species, for which the name Microcella aerolata sp. nov. is proposed, with GA224T as the type strain (= GDMCC 1.2165 T = JCM 34462 T).

Computational Study Revealing the Mechanistic Origin of Distinct Performances of P(O)-H/OH Compounds in Palladium-Catalyzed Hydrophosphorylation of Terminal Alkynes: Switchable Mechanisms and Potential Side Reactions.

Pd-catalyzed hydrophosphorylation of alkynes with P(O)-H compounds provided atom-economical and oxidant-free access to alkenylphosphoryl compounds. Nevertheless, the applicable P(O)-H substrates were limited to those without a hydroxyl group except H2P(O)OH. It is also puzzling that Ph2P(O)OH could co-catalyze the reaction to improve Markovnikov selectivity. Herein, a computational study was conducted to elucidate the mechanistic origin of the phenomena described above. It was found that switchable mechanisms influenced by the acidity of substrates and co-catalysts operate in hydrophosphorylation. In addition, potential side reactions caused by the protonation of PdII-alkenyl intermediates with P(O)-OH species were revealed. The regeneration of an active Pd(0) catalyst from the resulting Pd(II) complexes is remarkably slower than the hydrophosphonylation, while the downstream reactions, if possible, would lead to phosphorus 2-pyrone. Further analysis indicated that the side reactions could be suppressed by utilizing bulky substrates or ligands or by decreasing the concentration of P(O)-OH species. The presented switchable mechanisms and side reactions shed light on the co-transformations of P(O)-H and P-OH compounds in the Pd-catalyzed hydrophosphorylation of alkynes, clarify the origin of the distinct performances of P(O)-H/OH compounds, and provide theoretical clues for expanding the applicable substrate scope of hydrophosphorylation and synthesizing cyclic alkenylphosphoryl compounds.

EFEMP2 increases the invasion ability of cervical cancer cells by promoting EMT via the Raf/MEK/ERK signaling pathway.

EFEMP2 has been reported as a candidate oncogene. To investigate the role of EFEMP2 in cervical cancer cell proliferation and invasion, the mRNA and protein expressions of EFEMP2 in 5 different cervical cancer cell lines were detected. And then the effects of up- or down-regulation of EFEMP2 expression on the biological behavior of cervical cancer cells were further investigated by transfection experiments and cell function assays in vitro and in vivo. The results revealed that EFEMP2 was highly expressed in highly invasive Ca Ski cells and lowly expressed in less invasive HT-3 cells. When EFEMP2 was knocked down, the proliferation and invasion ability of cervical cancer cells were also reduced, accompanied by the decreased expression of MMP-1, MMP-13, MMP-3, and MMP-10, meanwhile, the EMT process was blocked and the Raf/MEK/ERK signaling pathway was inhibited. On the contrary, the upregulation of EFEMP2 could promote the proliferation and invasion of cervical cancer cells by inducing EMT and activating the Raf/MEK/ERK pathway. In conclusion, EFEMP2 could increase the invasion ability of cervical cancer cells by upregulating the expression of MMP-1, MMP-13, MMP-3, and MMP-10 and inducing the EMT process through the Raf/MEK/ERK pathway. EFEMP2 played a promoting role in the development of cervical cancer and provided a potential therapeutic target for inhibiting the invasion and metastasis of cancer cells and improving the prognosis of cervical cancer patients.

Ligand-Controlled Regiodivergent Cyanoboration of Internal Allenes by Copper Catalysis.

The first copper-catalyzed regiodivergent cyanoboration of internal allenes with B2 pin2 (bis(pinacolato)diboron) and NCTS (N-cyano-N-phenyl-p-toluenesulfonamide) derivatives is reported. The ß,γ- and α,ß-cyanoborylated products were synthesized with high regio- and stereo-selectivity. Computational studies revealed that nucleophilic addition of allylcopper or related intermediates on cyanation reagent is the regio- and stereo-determining step, while transmetalation with B2 pin2 is the rate-determining step. The nucleophilic addition step proceeds via inner-sphere mechanism in the CuI /P(o-tol)3 and CuI /Xantphos (P(o-tol)3 =tris(o-methylphenyl)phosphine, Xantphos=4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) catalytic systems and via outer-sphere mechanism in the CuII /Xantphos catalytic system, respectively.

Transient Stabilization Effect of CO2 in the Electrochemical Hydrogenation of Azo Compounds and the Reductive Coupling of α-Ketoesters.

The carbon dioxide (CO2 ) capture and utilization has attracted a great attention in organic synthesis. Herein, an unpresented transient stabilization effect (TSE) of CO2 is disclosed and well applied to the electrochemical hydrogenation of azo compounds to hydrazine derivatives. Mechanistic experiments and computational studies imply that CO2 can capture azo radical anion intermediates to protect the hydrogenation from potential degradation reactions, and is finally released through decarboxylation. The promotion effect of CO2 was further demonstrated to work in the preliminary study of electrochemical reductive coupling of α-ketoesters to vicinal diol derivatives. For the electrochemical reductive reactions mentioned above, CO2 is indispensable. The presented results shed light on a different usage of CO2 and could inspire novel experimental design by using CO2 as a transient protecting group.

The functional motions and related key residues behind the uncoating of coxsackievirus A16.

The coxsackievirus A16 (CVA16) is a highly contagious virus that causes the hand, foot, and mouth disease, which seriously threatens the health of children. At present, there are still no available antiviral drugs or effective treatments against the infection of CVA16, and thus it is of great significance to develop anti-CVA16 vaccines. However, the intrinsic uncoating property of the capsid may destroy the neutralizing epitopes and influence its immunogenicity, which hinders the vaccine developments. In the present work, the functional-quantity-based elastic network model analysis method developed by our group was extended to combine with group theory to investigate the uncoating motions of the CVA16 capsid, and then the functionally key residues controlling the uncoating motions were identified by our functional-quantity-based perturbation method. Several motion modes encoded in the topological structure of the capsid were revealed to be responsible for the uncoating of CVA16 particle. These modes predominantly contribute to the fluctuation of the gyration radius of the capsid. Then, by using the perturbation method, four clusters of key sites involved in the uncoating motions were identified, whose perturbations induce significant changes in the fluctuation of the gyration radius. These key residues are mainly located at the 2-fold channels, the quasi 3-fold channels, the bottom of the canyons, and the inter-subunit interfaces around the 3-fold axes. Our studies are helpful for better understanding the uncoating mechanism of the CVA16 capsid and provide potential target sites to prevent the uncoating motions, which is valuable for the vaccine design against CVA16.

Double-Regiodetermining-Stages Mechanistic Model Explaining the Regioselectivity of Pd-Catalyzed Hydroaminocarbonylation of Alkenes with Carbon Monoxide and Ammonium Chloride.

Pd-catalyzed hydroaminocarbonylation (HAC) of alkenes with CO and NH4Cl enables atom-economic and regiodivergent synthesis of primary amides, but the origin of regioselectivity was incorrectly interpreted in previous computational studies. A density functional theory study was performed herein to investigate the mechanism. Different from the previous proposals, both alkene insertion and aminolysis were found to be potential regioselectivity-determining stages. In the alkene insertion stage, 2,1-insertion is generally faster than 1,2-insertion irrespective of neutral or cationic pathways for both P(tBu)3 and xantphos. Such selectivity results from the unconventional proton-like hydrogen of the Pd-H bond in alkene insertion transition states. For less bulky alkenes, aminolysis with P(tBu)3 shows low selectivity, while linear selectivity dominates in this stage with xantphos due to a stronger repulsion between xantphos and branched acyl ligands. It was further revealed that the less-mentioned CO concentration and solvents also influence the regioselectivity by adjusting the relative feasibilities of CO-involved steps and NH3 release from ammonium chloride, respectively. The presented double-regiodetermining-stages mechanistic model associated with the effects of ligands, CO concentration, and solvents well reproduced the experimental selectivity to prove its validity and illuminated new perspectives for the regioselectivity control of HAC reactions.

Impact of periampullary diverticulum on biliary cannulation and ERCP outcomes: a single-center experience.

BACKGROUND: Periampullary diverticulum (PAD) is frequently come upon during endoscopic retrograde cholangiopancreatography (ERCP), especially in elderly patients. However, less is known about the role of PAD in biliary cannulation difficulty. AIM: This study aims to investigate the association of PAD and difficult cannulation and evaluate the impact of different types of PAD on the cannulation success rate and adverse events. METHODS: Prospectively collected data on a total of 636 patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) were divided into two groups based on the presence or absence of PAD. Besides, the patients were classified based on the PAD types into three groups. The primary outcomes were cannulation success rate, cannulation time, and ERCP-related adverse events. Further, the difficult cannulation and presence of PAD were analyzed using logistic regression models. RESULTS: Significant higher rates of biliary stones, cholangitis, and biliary pancreatitis were observed in the PAD group. Successful selective cannulation was achieved in 97.6% in the PAD group and 95.3% in the control group. The cannulation time was significantly longer in the presence of PAD. There was no significant difference in the rate of overall adverse events and post-ERCP pancreatic PEP. Multivariate analysis showed that type 1 PAD, biliary stones, and cholangitis were factors related to difficult cannulation. CONCLUSION: The presence of PAD did not affect the duration or success of the ERCP procedure. However, it was associated with longer cannulation time and an increase in the cannulation difficulty, especially with PAD type 1. Clinical Trial Study Registration This study is approved by Nanjing Medical University and registered at ClinicalTrial.gov PRS with ID/NCT03771547/.

Isolation and Identification of Pseudomonas sp. Strain DY-1 from Agricultural Soil and Its Degradation Effect on Prometryne.

Prometryne is a widely used herbicide in China to control annual grasses and broadleaf weeds. However, the stability of prometryne makes it difficult to be degraded, which poses a threat to human health. This study presents a bacterial strain isolated from soil samples with a prometryne application history, designated strain DY-1. Strain DY-1, identified as Pseudomonas sp., is capable of utilizing prometryne as a sole carbon source for growth and degrading 100% of prometryne within 48 h from an initial concentration of 50 mg L-1. To further optimize the degradation of prometryne, the prometryne concentration, temperature, pH, and salt concentration were examined. The optimal conditions for degradation of prometryne by strain DY-1 were an initial prometryne concentration of 50 mg L-1, 30 °C, pH 7-8, and NaCl concentration of 200 mg L-1. The same strain also degraded other s-triazine herbicides, including simetryne, ametryne, desmetryne, and metribuzin, under the same conditions. The biodegradation pathway of prometryne was established by isolating sulfoxide prometryne as the first metabolite and by the identification of sulfone prometryne and 2-hydroxy prometryne by liquid chromatography-mass spectrometry (LC-MS/MS). The results illustrated that strain DY-1 achieved the removal of prometryne by gradually oxidizing and hydrolyzing the methylthio groups. A bioremediation trial with contaminated soil and pot experiments showed that after treating the prometryne-contaminated soil with strain DY-1, the content of prometryne was significantly reduced (P < 0.05). This study provides an efficient bacterial strain and approach that could be potentially useful for detoxification and bioremediation of prometryne analogs.

Inverted Internal Limiting Membrane Flap Technique versus Internal Limiting Membrane Peeling for Large Macular Holes: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Vitrectomy with internal limiting membrane (ILM) peeling is an effective surgical procedure for the treatment of macular holes (MHs). However, there is a possibility of poor postoperative anatomical closure with conventional ILM peeling for MHs larger than 400 µm. Therefore, a novel inverted ILM flap technique was developed for such cases. OBJECTIVES: This meta-analysis study was performed to evaluate and compare the anatomical and visual outcomes of the inverted ILM flap technique and ILM peeling in large MHs. METHODS: The Cochrane Library, PubMed, and Embase databases were searched to identify randomized controlled trials (RCTs). The trial eligibility and risk of bias were assessed according to Cochrane review methods. The primary outcome measures included MH closure rate and postoperative visual acuity (VA). Subgroup analysis of postoperative VA based on follow-up time was also conducted. Pooled odds ratios (ORs), weighted mean difference (WMD), and 95% confidence intervals (CIs) were calculated. Statistical analysis was performed using RevMan 5.3 software. RESULTS: Five RCTs with a total of 155 eyes in the inverted ILM flap group and 161 eyes in the ILM peeling group were included in this meta-analysis. Statistical meta-analysis revealed that the overall MH closure rate in the inverted ILM flap group was significantly higher than that in the ILM peeling group (OR = 3.10; 95% CI: 1.25-7.66; p = 0.01). The postoperative VA was significantly better in the inverted ILM flap group than the ILM peeling group (WMD = -0.14; 95% CI: -0.21 to -0.07; p = 0.0002). The subgroup meta-analysis indicated that the postoperative VA was significantly better in the inverted ILM flap group than the ILM peeling group (WMD = -0.17; 95% CI: -0.26 to -0.08; p = 0.0004) at the 3-month follow-up. However, no significant difference was observed between the 2 groups at the 6-month follow-up (WMD = -0.09; 95% CI: -0.20 to 0.02; p = 0.10). CONCLUSIONS: Vitrectomy with the inverted ILM flap technique showed a higher anatomical closure rate as well as visual gain - although only in the short term as no difference in visual recovery was found at the 6-month follow-up - than did ILM peeling in large MHs. The inverted ILM flap technique should be considered as a preferred and routine procedure for the treatment of patients with MHs larger than 400 µm.