A mutant GH3 family ß-glucosidase from Oenococcus oeni exhibits superior adaptation to wine stresses and potential for improving wine aroma and phenolic profiles.

In this study, we conducted a comprehensive investigation into a GH3 family ß-glucosidase (BGL) from the wild-type strain of Oenococcus oeni and its mutated counterpart from the acid-tolerant mutant strain. Our analysis revealed the mutant BGL's remarkable capacity to adapt to wine-related stress conditions, including heightened tolerance to low pH, elevated ethanol concentrations, and metal ions. Additionally, the mutant BGL exhibited superior hydrolytic activity towards various substrates. Through de novo modeling, we identified specific amino acid mutations responsible for its resilience to low pH and high ethanol environments. In simulated wine conditions, the mutant BGL outperformed both wild-type and commercial BGLs, efficiently releasing terpene and phenolic aglycones from glycosides in wine grapes. These findings not only expand our understanding of O. oeni BGLs but also highlight their potential in enhancing wine production. The mutant BGL's enhanced adaptation to wine stress conditions opens promising avenue for improving wine quality and flavor.

KIAA1199 drives immune suppression to promote colorectal cancer liver metastasis by modulating neutrophil infiltration.

BACKGROUND AND AIMS: Metastasis is the primary cause of cancer mortality, and colorectal cancer (CRC) frequently metastasizes to the liver. Our previous studies demonstrated the critical role of KIAA1199 in tumor invasion and metastasis in CRC. In the present study, we described an immune regulatory effect of KIAA1199 that creates a permissive environment for metastasis. APPROACH AND RESULTS: Flow cytometry was used to examine the effects of KIAA1199 on the infiltration of tumor immune cells. Neutrophils and T cells were isolated, stimulated, and/or cultured for in vitro function assays. In the patients with CRC, high expression levels of KIAA1199 were associated with an increased neutrophil infiltration into the liver. This result was further validated in mouse metastasis models. The increased influx of neutrophils contributed to the KIAA1199-driven CRC liver metastasis. Mechanistically, KIAA1199 activated the TGFß signaling pathway by interacting with the TGFBR1/2 to stimulate CXCL1 and CXCL3 production, thereby driving the aggregation of immunosuppressive neutrophils. Genetic blockade or pharmacologic inhibition of KIAA1199 restored tumor immune infiltration, impeded tumor progression, and potentiated response to immune checkpoint blockade (ICB). CONCLUSIONS: These findings indicated that KIAA1199 could facilitate the liver infiltration of immunosuppressive neutrophils via the TGFß-chemokine (C-X-C motif) ligand (CXCL)3/1-CXCR2 axis, which might be clinically targeted for the treatment of hepatic metastasis.

Mechanism and Association between Microbial Nitrogen Transformation in Rhizosphere and Accumulation of Ciprofloxacin in Choysum (Brassica parachinensis).

Rhizosphere microbiota are an important factor impacting plant uptake of pollutants. However, little is known about how microbial nitrogen (N) transformation in the rhizosphere affects the uptake and accumulation of antibiotics in plants. Here, we determined recruitment of N transformation functional bacteria upon ciprofloxacin (CIP) exposure, by comparing differences in assembly processes of both rhizospheric bacterial communities and N transformation between two choysum (Brassica parachinensis) varieties differing in CIP accumulation. The low accumulation variety (LAV) of CIP recruited more host bacteria (e.g., Nitrospiria and Nitrolancea) carrying nitrification genes (mainly nxrA) but fewer host bacteria carrying denitrification genes, especially narG, relative to the high accumulation variety (HAV) of CIP. The nxrA and narG abundance in the LAV rhizosphere were, respectively, 1.6-7.8 fold higher and 1.4-3.4 fold lower than those in the HAV rhizosphere. Considering that nitrate can decrease CIP uptake into choysum through competing for the proton motive force and energy, such specific bacteria recruitment in LAV favored the production and utilization of nitrate in its rhizosphere, thus limiting its CIP accumulation with 1.6-2.4 fold lower than the HAV. The findings give insight into the mechanism underlying low pollutant accumulation, filling the knowledge gap regarding the profound effects of rhizosphere microflora and N transformation processes on antibiotic accumulation in crops.

Full components conversion of lignocellulose via a closed-circuit biorefinery process on a pilot scale.

This study developed a closed-circuit biorefinery process for full conversion of lignocellulose into ethanol, biogas and organic fertilizer with zero waste on a pilot scale. In the process, subcritical water pretreatment could effectively break the structure of wheat straw (WS), and ethanol was obtained from pretreated wheat straw (PWS) using two batches of simultaneous saccharification and fermentation (SSF). The pretreatment and ethanol fermentation wastes were reused for biogas and organic fertilizer production by anaerobic digestion (AD), whereas the pretreatment and ethanol conversion efficiency were reduced when supernatant after AD was recovered for next batch pretreatment. The yields of ethanol (0.08-0.09 g/g), biogas (0.05-0.10 L/g) and organic fertilizer (0.55-0.79 g/g) were demonstrated through mass balance. Furthermore, the hidden problems were exposed on pilot-scale conversion process, and several strategies were provided for optimizing the biorefinery process in the future.

Intermetallic Nanocatalyst for Highly Active Heterogeneous Hydroformylation.

Hydroformylation is an imperative chemical process traditionally catalyzed by homogeneous catalysts. Designing a heterogeneous catalyst with high activity and selectivity in hydroformylation is challenging but essential to allow the convenient separation and recycling of precious catalysts. Here, we report the development of an outstanding catalyst for efficient heterogeneous hydroformylation, RhZn intermetallic nanoparticles. In the hydroformylation of styrene, it shows three times higher turnover frequency (3090 h-1) compared to the benchmark homogeneous Wilkinson's catalyst (966 h-1), as well as a high chemoselectivity toward aldehyde products. RhZn is active for a variety of olefin substrates and can be recycled without a significant loss of activity. Density functional theory calculations show that the RhZn surfaces reduce the binding strength of reaction intermediates and have lower hydroformylation activation energy barriers compared to pure Rh(111), leading to more favorable reaction energetics on RhZn. The calculations also predict potential catalyst design strategies to achieve high regioselectivity.

A study of the possible role of Fab-glycosylated IgG in tumor immunity.

Previously we reported that administration of IgG could inhibit tumor progression in mouse models. At the same time, we also found that some IgGs have glycosylation modifications on their Fab fragments, which may have different biological functions than non-glycosylated IgG. In this study, we employed mouse tumor models to explore the roles of two different forms of IgG, i.e. Fab-glycosylated and Fab-non-glycosylated IgG, in tumor progression. The two types of IgGs were separated with ConA absorption which could react with glycan on the Fab arm but could not access glycan on the Fc fragment. In addition, we performed cytokine array, ELISA, western blotting, immunocytochemistry and other techniques to investigate the possible mechanisms of the actions of Fab-glycosylated IgG in the models. We found that Fab-glycosylated IgG, unlike Fab-non-glycosylated IgG, did not inhibit tumor growth and metastasis in the model. On the contrary, Fab-glycosylated IgG may bind to antigen-bound IgG molecules and macrophages through the glycosidic chain on the Fab fragment to affect antigen-antibody binding and macrophage polarization, which are likely to help tumor cells to evade the immune surveillance. A new mechanism of immune evasion with Fab-glycosylated IgG playing a significant role was proposed.

Carbapenem-resistant K. pneumoniae exhibiting clinically undetected amikacin and meropenem heteroresistance leads to treatment failure in a murine model of infection.

Heteroresistance is a poorly understood mechanism of resistance which refers to a phenomenon where there are different subpopulations of seemingly isogenic bacteria which exhibit a range of susceptibilities to a particular antibiotic. In the current study, we identified a multidrug-resistant, carbapenemase-positive K. pneumoniae strain SWMUF35 which was classified as susceptible to amikacin and resistant to meropenem by clinical diagnostics yet harbored different subpopulations of phenotypically resistant cells, and has the ability to form biofilm. Population analysis profile (PAP) indicated that SWMUF35 showed heteroresistance towards amikacin and meropenem which was considered as co-heteroresistant K. pneumoniae strain. In vitro experiments such as dual PAP, dual Times-killing assays and checkerboard assay showed that antibiotic combination therapy (amikacin combined with meropenem) can effectively combat SWMUF35. Importantly, using an in vivo mouse model of peritonitis, we found that amikacin or meropenem monotherapy was unable to rescue mice infected with SWMUF35. Antibiotic combination therapy could be a rational strategy to use clinically approved antibiotics when monotherapy would fail. Furthermore, our data warn that antibiotic susceptibility testing results may be unreliable due to undetected heteroresistance which can lead to treatment failure and the detection of this phenotype is a prerequisite for a proper choice of antibiotic to support a successful treatment outcome.

Structure evolution of single-site Pt in a metal-organic framework.

Heterogeneous single-metal-site catalyst or single-atom catalyst research has grown rapidly due to the accessibility of modern characterization techniques that can provide invaluable information at the atomic-scale. Herein, we study the structural evolution of isolated single Pt sites incorporated in a metal-organic framework containing bipyridine functional groups using in situ diffuse reflectance infrared Fourier transform spectroscopy with CO as the probe molecule. The structure and electronic properties of the isolated Pt sites are further corroborated by x-ray photoelectron spectroscopy and aberration-corrected scanning transmission electron microscopy. We find the prerequisite of high temperature He treatment for Pt activation and CO insertion and inquire into the structural transformation of Pt site process by dynamic nuclear polarization-enhanced solid-state nuclear magnetic resonance spectroscopy.

Thermal Unequilibrium of PdSn Intermetallic Nanocatalysts: From In Situ Tailored Synthesis to Unexpected Hydrogenation Selectivity.

Effective control on chemoselectivity in the catalytic hydrogenation of C=O over C=C bonds is uncommon with Pd-based catalysts because of the favored adsorption of C=C bonds on Pd surface. Here we report a unique orthorhombic PdSn intermetallic phase with unprecedented chemoselectivity toward C=O hydrogenation. We observed the formation and metastability of this PdSn phase in situ. During a natural cooling process, the PdSn nanoparticles readily revert to the favored Pd3 Sn2 phase. Instead, using a thermal quenching method, we prepared a pure-phase PdSn nanocatalyst. PdSn shows an >96 % selectivity toward hydrogenating C=O bonds of various α,ß-unsaturated aldehydes, highest in reported Pd-based catalysts. Further study suggests that efficient quenching prevents the reversion from PdSn- to Pd3 Sn2 -structured surface, the key to the desired catalytic performance. Density functional theory calculations and analysis of reaction kinetics provide an explanation for the observed high selectivity.

Effect of rpoE on the Non-coding RNA Expression Profiles of Salmonella enterica serovar Typhi under the Stress of Ampicillin.

Gene transcription in bacteria is mainly triggered by sigma factors (σ factors), such as rpoE. Bacterial ncRNAs are key players in reprogramming protein transcription when the environment changes. In our experiment, under the stress of ampicillin, the ncRNA transcriptomes of Salmonella enterica serovar Typhi wild-type strain (WT) and rpoE-deficient strain (ΔrpoE) were sequenced and analyzed, and four ncRNAs were selected to be verified by qRT-PCR. Of the ncRNA transcripts tested, 57 ncRNAs were found to have significantly different expressions (fold changes > 2) in ΔrpoE compared to WT, with 31 being upregulated and 26 being downregulated. The expression levels of the four ncRNAs verified preliminarily by subsequent qRT-PCR showed consistency with the sequencing data. Our study revealed the differences in ncRNA expression profiles between Salmonella enterica serovar Typhi WT and ΔrpoE under ampicillin stress. The four ncRNAs identified by qRT-PCR and their associated signaling pathways may be related to the envelope stress and antibiotic susceptibility of Salmonella enterica serovar Typhi.

Study on the absorption of corosolic acid in the gastrointestinal tract and its metabolites in rats.

Corosolic acid (CRA) has been widely used as a food supplement. However, its pharmacokinetic behavior still needs to be explored. In this study, the absorption of CRA in stomach and intestine were investigated by in situ gastric absorption and in situ single-pass perfusion, respectively. Furthermore, the metabolites of CRA in rat plasma, bile, and urine were identified by UPLC-QTOF-MS. The enzymes responsible for its metabolism were explored by rat liver microsome (RLMs). The effects of plasma containing metabolites on cancer cell growth and glucose consumption were evaluated by HT29 and HepG2 cells receptively. The results showed that CRA absorption rate is approximately 20% to 40% in stomach. It has similar absorption rate constant (Ka) in duodenum/jejunum/ileum/colon. However, its effective permeability (Peff) in ileum at 9 µg/mL is significantly higher than the Peff in colon. Moreover, five possible metabolites were identified in plasma and bile, suggesting CRA could be metabolized through methyl carboxylation, hydroxylation, methyl aldehyde substitution, glucuronidation, and acetylation in vivo. Meanwhile, CYP1A2 and CYP3A4 were found to participate in its metabolism. The plasma containing metabolites of CRA significantly inhibited the growth of HT29 colon cancer cells and stimulated glucose consumption of HepG2 cells. Taken together, these results demonstrated that CRA has good absorption in both stomach and small intestine, but it could be metabolized partly due to CYP1A2 and CYP3A4 in vivo. Its metabolites might be responsible for the excellent anti-cancer and anti-diabetes activities of CRA. This study will provide evidence for further CRA development.

Paris Saponin II inhibits colorectal carcinogenesis by regulating mitochondrial fission and NF-κB pathway.

Colorectal cancer (CRC) is one of the leading causes of cancer-related morbidity and mortality worldwide. Accumulating evidence suggests that mitochondrial dynamics are closely implicated in carcinogenesis including CRC. Paris Saponin II (PSII), a major steroidal saponin extracted from Rhizoma Paris polyphylla, has emerged as a potential anticancer agent. However, the effects of PSII on CRC and its underlying mechanisms remain unknown. In the present study, we found PSII induced apoptosis and inhibited colony formation in HT 29 and HCT 116 cells, and cell cycle arrest in G1 phase. PSII inhibited the phosphorylation of ERK1/2 and mitochondrial translocation of dynamin-related protein 1 (Drp1) by dephosphorylating Drp1 at Ser616, leading to the suppression of mitochondrial fission. PSII also suppressed NF-κB activation as a result of the inhibition of IKKß and p65 translocation. Drp1 knockdown remarkably downregulated the nuclear expression of p65 and its target genes cyclin D1 and c-Myc in HCT 116 cell, confirming the link between mitochondrial fission and NF-κB pathway. Silencing of Drp 1 enhanced the inhibitory effects of PSII on p65 phosphorylation and the expressions of cyclin D1 and c-Myc, revealing that the inhibitory effects of PSII on cyclin D1 and c-Myc were relevant in the suppression of Drp1 and NF-κB activation. An in vivo study demonstrated PSII remarkably decreased the xenograft tumor size and suppressed the phosphorylation of ERK1/2 and Drp1 at Ser616. Taken together, our results suggested that PSII could inhibit colorectal carcinogenesis, at least in part, by regulating mitochondrial fission and NF-κB pathway.

Tracing the Therapeutic Process of Targeted Aptamer/Drug Conjugate on Cancer Cells by Surface-Enhanced Raman Scattering Spectroscopy.

Targeted delivery of chemotherapeutic agents to pathology areas can improve drug efficiency and reduce serious side effects on normal regions. However, their treatment mechanism on cells or cell nuclei is still mysterious due to the lack of in situ characterization methods. In this paper, the specific diagnosis and treatment processes of a targeted antitumor agent (doxorubicin, Dox) functionalized aptamer complex (TLS11a-GC-Dox) toward HepG2 cells, a human hepatocellular carcinoma cell line, were tracked in real time by the surface-enhanced Raman scattering (SERS) spectroscopic technique and dark-field imaging with the assistance of gold nanorod-based nuclear targeted probes, which possess remarkable SERS enhancement ability, specific targeting, and excellent biological compatibility. This is the first time to explore the acting mechanism of an aptamer-based targeted drug on cell nucleus based on the spectral information on components inside the cell nucleus. The results demonstrate that this aptamer/drug conjugate has targeting and sustained-release actions and its therapeutic effect is achieved by the gradual damage of relevant proteins and DNA in nuclei. Better understanding of the mechanism of aptamer-drug conjugates acting on cancer cells is conductive to increasing cancer therapy efficiency and is also helpful for the design of highly effective drug delivery methods.

Metal-Organic-Framework-Derived Carbons: Applications as Solid-Base Catalyst and Support for Pd Nanoparticles in Tandem Catalysis.

The facile pyrolysis of a bipyridyl metal-organic framework, MOF-253, produces N-doped porous carbons (Cz-MOF-253), which exhibit excellent catalytic activity in the Knoevenagel condensation reaction and outperform other nitrogen-containing MOF-derived carbons. More importantly, by virtue of their high Lewis basicity and porous nature, Cz-MOF-253-supported Pd nanoparticles (Pd/Cz-MOF-253-800) show excellent performance in a one-pot sequential Knoevenagel condensation-hydrogenation reaction.

Cooperative Multifunctional Catalysts for Nitrone Synthesis: Platinum Nanoclusters in Amine-Functionalized Metal-Organic Frameworks.

Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine-functionalized Zr metal-organic framework (MOF), UiO-66-NH2 (Pt@UiO-66-NH2 ) as a multifunctional catalyst in the one-pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO-66-NH2 , Pt@UiO-66-NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO-66, and Pd@UiO-66-NH2 . Pt@UiO-66-NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO-66-NH2 ). To our knowledge, this work demonstrates the first examples of one-pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.

Glucose oxidase probe as a surface-enhanced Raman scattering sensor for glucose.

Glucose oxidase (GOx) possessing a Raman-active chromophore (flavin adenine dinucleotide) is used as a signal reporter for constructing a highly specific "turn off" surface-enhanced Raman scattering (SERS) sensor for glucose. This sensing chip is made by the electrostatic assembly of GOx over silver nanoparticle (Ag NP)-functionalized SERS substrate through a positively charged polyelectrolyte linker under the pH of 6.86. To trace glucose in blood serum, owing to the reduced pH value caused by the production of gluconic acid in the GOx-catalyzed oxidation reaction, the bonding force between GOx and polyelectrolyte weakens, making GOx drop off from the sensing chip. As a result, the SERS intensity of GOx on the chip decreases along with the concentration of glucose. This glucose SERS sensor exhibits excellent selectivity based on the specific GOx/glucose catalysis reaction and high sensitivity to 1.0 µM. The linear sensing range is 2.0-14.0 mM, which also meets the requirement on the working range of the human blood glucose detection. Using GOx as a probe shows superiority over other organic probes because GOx almost has no toxicity to the biological system. This sensing mechanism can be applied for intracellular in vivo SERS monitoring of glucose in the future. Graphical abstract Glucose oxidase is used as a Raman signal reporter for constructing a highly specific glucose surface-enhanced Raman scattering (SERS) sensor.

AmyM, a Novel Maltohexaose-Forming α-Amylase from Corallococcus sp. strain EGB.

A novel α-amylase, AmyM, was purified from the culture supernatant of Corallococcus sp. strain EGB. AmyM is a maltohexaose-forming exoamylase with an apparent molecular mass of 43 kDa. Based on the results of matrix-assisted laser desorption ionization-time of flight mass spectrometry and peptide mass fingerprinting of AmyM and by comparison to the genome sequence of Corallococcus coralloides DSM 2259, the AmyM gene was identified and cloned into Escherichia coli. amyM encodes a secretory amylase with a predicted signal peptide of 23 amino acid residues, which showed no significant identity with known and functionally verified amylases. amyM was expressed in E. coli BL21(DE3) cells with a hexahistidine tag. The signal peptide efficiently induced the secretion of mature AmyM in E. coli. Recombinant AmyM (rAmyM) was purified by Ni-nitrilotriacetic acid (NTA) affinity chromatography, with a specific activity of up to 14,000 U/mg. rAmyM was optimally active at 50°C in Tris-HCl buffer (50 mM; pH 7.0) and stable at temperatures of <50°C. rAmyM was stable over a wide range of pH values (from pH 5.0 to 10.0) and highly tolerant to high concentrations of salts, detergents, and various organic solvents. Its activity toward starch was independent of calcium ions. The Km and Vmax of recombinant AmyM for soluble starch were 6.61 mg ml(-1) and 44,301.5 µmol min(-1) mg(-1), respectively. End product analysis showed that maltohexaose accounted for 59.4% of the maltooligosaccharides produced. These characteristics indicate that AmyM has great potential in industrial applications.

Neural basis responsible for effect of grit on procrastination: The interaction between the self-regulation and motivation neural pathways.

Procrastination has a detrimental impact on academic performance, health, and subjective well-being. Previous studies indicated that grit was negatively related to procrastination. However, the underlying neural basis of this relationship remains unclear. To address this issue, we utilized voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) analysis to identify the neural substrates of how is grit linked to procrastination. Behavioral results showed that procrastination was negatively associated with grit. VBM analysis revealed that gray matter volume (GMV) in the left precuneus was positively associated with the consistency of interest (CI), a subcomponent of grit, while the right medial orbital frontal cortex (mOFC) was positively correlated with the perseverance of effort (PE), another subcomponent of grit. Moreover, the RSFC analysis indicated that both precuneus-medial superior frontal gyrus (mSFG) and precuneus-insula connectivity were positively related to CI, while the functional coupling of right mOFC with left anterior cingulate cortex (ACC) was positively related to PE. Importantly, the structural equation modeling (SEM) results were well suited for the influence of grit on procrastination via both self-regulation (mOFC-ACC) and motivation pathways (precuneus-mSFG, precuneus-insula). Together, these findings imply that self-regulation and motivation could be two neural circuits underlying the impact of grit on procrastination.

Foodomics uncovers functional and volatile metabolite dynamics in red raspberry chewable tablet optimized processing.

Raspberries are known to contain valuable metabolites and possess a robust antioxidant capacity. However, the impact of different tablet processing stages on the nutritional content and flavor profile of raspberries remains unclear. The dynamic profile of functional and volatile metabolites was investigated through foodomics combined with UPLC-MS/MS-based widely targeted metabolomics and HS-SPME-GC-MS, and antioxidant capacities were assessed during tablet processing. 1336 functional metabolites and 645 volatile metabolites were identified. Results indicated tablets retained 34% âˆ¼ 61% of the total volatile contents. In addition, the conversion intensity of functional metabolites was consistent with the order of "Tableting > Freeze-drying > Crushing". Compared to raspberry, tablets showed higher antioxidant activity, which was positively correlated with vitamin contents. This study elucidated that tablet formation demonstrated advantages in antioxidation and aroma retention, which may provide insights for enhancing quality during the tableting process.

Myofibrillar protein hydrolysis under hydroxyl radical oxidative stress: Structural changes and their impacts on binding to selected aldehydes.

In this study, a hydroxyl radical oxidation system was established to simulate the oxidation process in fermented meat products. This system was employed to examine the structural changes in myofibrillar proteins (MPs) resulting from tryptic hydrolysis after a hydroxyl radical oxidative regime. The effect of these changes on the ability of MPs to bind selected aldehydes (3-methyl butanal, pentanal, hexanal, and heptanal) was also investigated. Moderate oxidation (H2O2 ≤ 1.0 mM) unfolded the structure of MPs, facilitating trypsin-mediated hydrolysis and increasing their binding capacity for the four selected aldehydes. However, excessive oxidation (H2O2 ≥ 2.5 mM) led to cross-linking and aggregation of MPs, inhibiting trypsin-mediated hydrolysis. The oxidised MPs had the best binding capacity for heptanal. The interaction of the oxidised trypsin-hydrolysed MPs with heptanal was driven by hydrophobic interactions. The binding of heptanal affected the structure of the oxidised trypsin-hydrolysed MPs and reduced their α-helix content.