Metabolic engineering of Pichia pastoris for overproduction of cis-trans nepetalactol.

Monoterpene indole alkaloids (MIAs) are a group of plant-derived natural products with high-value medicinal properties. However, their availability for clinical application is limited due to challenges in plant extraction. Microbial production has emerged as a promising strategy to meet the clinical demands for MIAs. The biosynthetic pathway of cis-trans nepetalactol, which serves as the universal iridoid scaffold for all MIAs, has been successfully identified and reconstituted. However, bottlenecks and challenges remain to construct a high-yielding platform strain for cis-trans nepetalactol production, which is vital for subsequent MIAs biosynthesis. In the present study, we focused on engineering of Pichia pastoris cell factories to enhance the production of geraniol, 8-hydroxygeraniol, and cis-trans nepetalactol. By targeting the biosynthetic pathway from acetyl-CoA to geraniol in both peroxisomes and cytoplasm, we achieved comparable geraniol titers in both compartments. Through protein engineering, we found that either G8H or CPR truncation increased the production of 8-hydroxygeraniol, with a 47.8-fold and 14.0-fold increase in the peroxisomal and cytosolic pathway strain, respectively. Furthermore, through a combination of dynamical control of ERG20, precursor and cofactor supply engineering, diploid engineering, and dual subcellular compartmentalization engineering, we achieved the highest ever reported production of cis-trans nepetalactol, with a titer of 4429.4 mg/L using fed-batch fermentation in a 5-L bioreactor. We anticipate our systematic metabolic engineering strategies to facilitate the development of P. pastoris cell factories for sustainable production of MIAs and other plant natural products.

Characterization and engineering of peroxisome targeting sequences for compartmentalization engineering in Pichia pastoris.

Peroxisomal compartmentalization has emerged as a highly promising strategy for reconstituting intricate metabolic pathways. In recent years, significant progress has been made in the peroxisomes through harnessing precursor pools, circumventing metabolic crosstalk, and minimizing the cytotoxicity of exogenous pathways. However, it is important to note that in methylotrophic yeasts (e.g. Pichia pastoris), the abundance and protein composition of peroxisomes are highly variable, particularly when peroxisome proliferation is induced by specific carbon sources. The intricate subcellular localization of native proteins, the variability of peroxisomal metabolic pathways, and the lack of systematic characterization of peroxisome targeting signals have limited the applications of peroxisomal compartmentalization in P. pastoris. Accordingly, this study established a high-throughput screening method based on ß-carotene biosynthetic pathway to evaluate the targeting efficiency of PTS1s (Peroxisome Targeting Signal Type 1) in P. pastoris. First, 25 putative endogenous PTS1s were characterized and 3 PTS1s with high targeting efficiency were identified. Then, directed evolution of PTS1s was performed by constructing two PTS1 mutant libraries, and a total of 51 PTS1s (29 classical and 22 noncanonical PTS1s) with presumably higher peroxisomal targeting efficiency were identified, part of which were further characterized via confocal microscope. Finally, the newly identified PTS1s were employed for peroxisomal compartmentalization of the geraniol biosynthetic pathway, resulting in more than 30% increase in the titer of monoterpene compared with when the pathway was localized to the cytosol. The present study expands the synthetic biology toolkit and lays a solid foundation for peroxisomal compartmentalization in P. pastoris.

Protective effect of feed additive ferulic acid on respiratory depression and oxidation imbalance of carp induced by pesticide difenoconazole via ROS/NF-κB/NLRP3 axis.

Difenoconazole (DFZ), classified as a "low-toxicity pesticide," has seen widespread application in recent years. Nevertheless, the non-target toxicity of the substance, particularly towards aquatic creatures, has generated considerable apprehension. The anti-inflammatory and antioxidant effects of Ferulic Acid (FA) have attracted considerable study in this particular setting. This study established a chronic exposure model to DFZ and investigated the protective effects of FA on chronic respiratory inhibition leading to gill damage in freshwater carp. Histological analyses via HE staining indicated that FA effectively alleviated gill tissue damage induced by chronic DFZ exposure. The qRT-PCR results showed that the addition of FA reduced the expression of IL-1ß, IL-6 and TNF-α while boosting the expression of IL-10 and TGF-ß1. Biochemical analyses and DHE staining revealed that FA reduced MDA levels and increased CAT and GSH activities, along with T-AOC, decreased ROS accumulation in response to chronic DFZ exposure. The results obtained from Western blotting analysis demonstrated that the addition of FA effectively suppressed the activation of the NF-κB signalling pathway and the NLRP3 inflammasome pathway in the gills subjected to prolonged exposure to DFZ. In summary, FA ameliorated gill tissue inflammation and blocked ROS accumulation in carp exposed to chronic DFZ, mitigating tissue inflammation and restoring redox homeostasis through the NF-κB-NLRP3 signaling pathway. Hence, the application of FA has been found to be efficacious for improving respiratory inhibition and mitigating gill tissue inflammation and oxidative stress resulting from DFZ pollution in aquatic habitats.

Silybin mitigated liver and brain damage after difenoconazole exposure: Crosstalk between oxidative stress, inflammation, ferroptosis and apoptosis.

Long-term residue of difenoconazole (DFZ) in the environment caused multiple organ damage to aquatic organisms. Due to the potential hepatoprotective and neuroprotective properties of silybin (SIL), we hypothesized that SIL could alleviate growth inhibition, liver, and brain damage in carp induced by DFZ exposure. The in vivo experiments were divided into the Control group, the SIL group, the DFZ group and the DFZ + SIL group. The exposure concentration of DFZ was 0.39 mg/L, and the therapeutic dose of SIL was 400 mg/kg. The whole experiment lasted for 30 days. SIL was also found to reduce hepatic injury and lipid metabolism based on H&E staining, oil red O staining, and measurement of serum and liver tissue levels of ALT, AST, LDH, TG, and TC. Similarly, SIL reduced brain damage after DFZ exposure, according to H&E staining and detection transcription level of the ZO-1, ZO-2, occludin, and Claudin7 in carp brain. In terms of mechanism, the results showed that SIL inhibited the excessive production of ROS in liver and brain tissues, increased the activity of antioxidant enzymes (T-AOC, SOD, CAT) and resist oxidative stress. Also, SIL promoted the production of anti-inflammatory factors (TGF-ß1 and IL-10) and inhibited the expression of pro-inflammatory factors (TNF-α and IL-6) to reduce the inflammatory response in liver and brain tissues caused by DFZ. ln terms of ferroptosis, by lowering iron levels, upregulating ferroptosis-related genes (GPX4, SIC7A11, GCLC), and downregulating the expression of NCOA4, STEAP3, COX2, and P53, SIL was able to inhibit ferroptosis of liver and brain tissues of carp. In addition, SIL restored the reduced mitochondrial membrane potential (MMP) level and inhibited apoptosis as measured by MMP level detection, TUNEL staining, and apoptosis gene transcript levels. In this study, we analyzed the interactions between genes and proteins associated with oxidative stress, inflammation, ferroptosis and apoptosis using the String database and ranked the nodes in the network using the Cytoscape plugin Cytohubba, and found that P53, Caspase3, TNF-α, IL-6 and Bcl-2 were the key hub genes. Our study not only revealed the multiple pharmacological activities of SIL, but also provided a reference for the prevention and reduction pesticide hazards to aquatic organisms.

Synergistic effects of ferulic acid esterase-producing lactic acid bacteria, cellulase and xylanase on the fermentation characteristics, fibre and nitrogen components and microbial community structure of Broussonetia papyrifera during ensiling.

BACKGROUND: The high fibre content of whole plants of Broussonetia papyrifera limits its efficient utilization. Ferulic acid esterase (FAE), in combination with xylanase, can effectively cleave the lignin-carbohydrate complex, promoting the function of cellulase. However, little is known about the impact of these additives on silage. To effectively utilize natural woody plant resources, FAE-producing Lactiplantibacillus plantarum RO395, xylanase (XY) and cellulase (CE) were used to investigate the dynamic fermentation characteristics, fibre and nitrogen components and microbial community structure during B. papyrifera ensiling. RESULTS: Broussonetia papyrifera was either not treated (CK) or treated with FAE-producing lactic acid bacteria (LP), CE, XY, LP + CE, LP + XY or LP + CE + XY for 3, 7, 15, 30 or 60 days, respectively. In comparison with those in the CK treatment, the L. plantarum and enzyme treatments (LP + CE, LP + XY and LP + XY + CE), especially the LP + XY + CE treatment, significantly increased the lactic acid concentration and decreased the pH and the contents of acid detergent insoluble protein and NH3 -N (P < 0.05). Enzyme addition improved the degradation efficiency of lignocellulose, and a synergistic effect was observed after enzyme treatment in combination with LP; in addition, the lowest acid detergent fibre, neutral detergent fibre, hemicellulose and cellulose contents were detected after the LP + CE + XY treatment (P < 0.05). Moreover, CE, XY and LP additions significantly improved the microbial community structure, increased the relative abundance of Lactiplantibacillus and Firmicutes, and effectively inhibited undesirable bacterial (Enterobacter) growth during ensiling. CONCLUSION: FAE-producing L. plantarum and the two tested enzymes exhibited synergistic effects on improving the quality of silage, which indicates that this combination can serve as an efficient method for improved B. papyrifera silage utilization. © 2023 Society of Chemical Industry.

Vitamin D3 alleviates lung fibrosis of type 2 diabetic rats via SIRT3 mediated suppression of pyroptosis.

PURPOSE: We aimed to evaluate whether pulmonary fibrosis occurs in type 2 diabetes rat models and whether VD3 can prevent it by inhibiting pyroptosis. METHODS: Sprague-Dawley rats were assigned to normal control (NC), diabetic model control (MC), low-dose VD3 (LVD), medium-dose VD3 (MVD), high-dose VD3 (HVD) and metformin positive control (PC) groups. Type 2 diabetes model was induced by a high-sugar, high-fat diet combined with STZ injection, and subsequently intervened with VD3 or metformin for 10 weeks. Blood glucose, body weight, food intake, water intake, urine volume, morphology, lung hydroxyproline level, immunohistochemistry, TUNEL staining, inflammatory cytokines secretion and related protein expression were analyzed. RESULTS: Diabetic rats exhibited significant impairments in fasting blood glucose, insulin resistance, body weight, food intake, water intake, and urine volume. While morphological parameters, diabetic rats exhibited severe lung fibrosis. Intriguingly, VD3 intervention reversed, at least in part, the diabetes-induced alterations. The expression of pyroptosis-related proteins was up-regulated in diabetic lungs whereas the changes were reversed by VD3. In the meanwhile, SIRT3 expression was down-regulated in diabetic lungs while VD3 up-regulated it. CONCLUSION: Fibrotic changes were observed in diabetic rat lung tissue and our study indicates that VD3 may effectively ameliorate diabetic pulmonary fibrosis via SIRT3-mediated suppression of pyroptosis.

Histone chaperone SSRP1 is required for apoptosis inhibition and mitochondrial function in HCC via transcriptional promotion of TRAP1.

Epigenetic regulation contributes to human health and disease, especially cancer, but the mechanisms of many epigenetic regulators remain obscure. Most research is focused on gene regulatory processes, such as mRNA translation and DNA damage repair, rather than the effects on biological functions like mitochondrial activity and oxidative phosphorylation. Here, we identified an essential role for the histone chaperone structure-specific recognition protein 1 (SSRP1) in mitochondrial oxidative respiration in hepatocellular carcinoma, and found that SSRP1 suppression led to mitochondrial damage and decreased oxidative respiration. Further, we focused on TNF receptor-associated protein 1 (TRAP1), the only member of the heat shock protein 90 (HSP90) family, which directly interacts with selected respiratory complexes and affects their stability and activity. We confirmed that SSRP1 downregulation caused a decrease in TRAP1 expression at both the mRNA and protein levels. A chromatin immunoprecipitation assay also showed that SSRP1 could deposit in the TRAP1 promoter region, indicating that SSRP1 maintains mitochondrial function and reactive oxygen species levels through TRAP1. Additionally, rescue experiments and animal experiments confirmed the mechanism of SSRP1 and TRAP1 interaction. In summary, we identified a new mechanism that connects mitochondrial respiration and apoptosis, via SSRP1.

Roles of the cytoskeleton in human diseases.

Recently, researches have revealed the key roles of the cytoskeleton in the occurrence and development of multiple diseases, suggesting that targeting the cytoskeleton is a viable approach for treating numerous refractory diseases. The cytoskeleton is a highly structured and complex network composed of actin filaments, microtubules, and intermediate filaments. In normal cells, these three cytoskeleton components are highly integrated and coordinated. However, the cytoskeleton undergoes drastic remodeling in cytoskeleton-related diseases, causing changes in cell polarity, affecting the cell cycle, leading to senescent diseases, and influencing cell migration to accelerate cancer metastasis. Additionally, mutations or abnormalities in cytoskeletal proteins and their related proteins are closely associated with several congenital diseases. Therefore, this review summarizes the roles of the cytoskeleton in cytoskeleton-related diseases as well as its potential roles in disease treatment to provide insights regarding the physiological functions and pathological roles of the cytoskeleton.

Binding of berberine derivates to G-quadruplex: insight from a computational study.

Human telomerase exhibits significant activity in cancer cells relative to normal cells, which contributes to the immortal proliferation of cancer cells. To counter this, the stabilization of G-quadruplexes formed in the guanine-rich sequence of the cancer cell chromosome has emerged as a promising avenue for anti-cancer therapy. Berberine (BER), an alkaloid that is derived from traditional Chinese medicines, has shown potential for stabilizing G-quadruplexes. To investigate the atomic interactions between G-quadruplexes and BER and its derivatives, molecular dynamics simulations were conducted. Modeling the interactions between G-quadruplexes and ligands accurately is challenging due to the strong negative charge of nucleic acids. Thus, various force fields and charge models for the G-quadruplex and ligands were tested to obtain precise simulation results. The binding energies were calculated by a combination of molecular mechanics/generalized Born surface area and interaction entropy methods, and the calculated results correlated well with experimental results. B-factor and hydrogen bond analyses demonstrated that the G-quadruplex was more stable in the presence of ligands than in the absence of ligands. Calculation of the binding free energy showed that the BER derivatives bind to a G-quadruplex with higher affinity than that of BER. The breakdown of the binding free energy to per-nucleotide energies suggested that the first G-tetrad played a primary role in binding. Additionally, energy and geometric properties analyses indicated that van der Waals interactions were the most favorable interactions between the derivatives and the G-quadruplexes. Overall, these findings provide crucial atomic-level insights into the binding of G-quadruplexes and their inhibitors.

Development of a Stable Oxygen Sensor Using a 761 nm DFB Laser and Multi-Pass Absorption Spectroscopy for Field Measurements.

An optical sensor system based on wavelength modulation spectroscopy (WMS) was developed for atmospheric oxygen (O2) detection. A distributed feedback (DFB) laser with butterfly packaging was used to target the O2 absorption line at 760.89 nm. A compact multi-pass gas cell was employed to increase the effective absorption length to 3.3 m. To ensure the stability and anti-interference capability of the sensor in field measurements, the optical module was fabricated with isolation of ambient light and vibration design. A 1f normalized 2f WMS (WMS-2f/1f) technique was adopted to reduce the effect of laser power drift. In addition, a LabVIEW-based dual-channel lock-in amplifier was developed for harmonic detection, which significantly reduced the sensor volume and cost. The detailed detection principle was described, and a theoretical model was established to verify the effectiveness of the technique. Experiments were carried out to obtain the device's sensing performances. An Allan deviation analysis yielded a minimum detection limit of 0.054% for 1 s integration time that can be further improved to 0.009% at ~60 s. Finally, the reliability and anti-interference capability of the sensor system were verified by the atmospheric O2 monitoring.

Anesthetic Management of Patients with Dilated Cardiomyopathy Undergoing Noncardiac Surgery.

Dilated cardiomyopathy (DCM), a primary myocardial disease, is characterized by dilation of the left or both ventricles and systolic dysfunction with or without congestive heart failure. DCM per se is a well-recognized risk factor for sudden cardiac death and poor surgical outcomes following noncardiac surgery. Surgical trauma/stress represents unique challenges for DCM patient management. Unfortunately, there is a big knowledge gap in managing DCM patients undergoing non-cardiac surgery. Therefore, the aim of our review is to provide basic facts and current advances in DCM, as well as a practical guideline to perioperative care providers, for the management of surgical patients with DCM, who are quite rare compared with the general surgical population. This review summarizes recent advances in the medical management of DCM as well as perioperative assessment and management strategies for DCM patients undergoing noncardiac surgery. Optimal surgical outcomes depend on multiple-disciplinary care to minimize perioperative cardiovascular disturbances.

A fast-slow method to treat solute dynamics in explicit solvent.

Aiming to reduce the computational cost in the current explicit solvent molecular dynamics (MD) simulation, this paper proposes a fast-slow method for the fast MD simulation of biomolecules in explicit solvent. This fast-slow method divides the entire system into two parts: a core layer (typically solute or biomolecule) and a peripheral layer (typically solvent molecules). The core layer is treated using standard MD method but the peripheral layer is treated by a slower dynamics method to reduce the computational cost. We compared four different simulation models in testing calculations for several small proteins. These include gas-phase, implicit solvent, fast-slow explicit solvent and standard explicit solvent MD simulations. Our study shows that gas-phase and implicit solvent models do not provide a realistic solvent environment and fail to correctly produce reliable dynamic structures of proteins. On the other hand, the fast-slow method can essentially reproduce the same solvent effect as the standard explicit solvent model while gaining an order of magnitude in efficiency. This fast-slow method thus provides an efficient approach for accelerating the MD simulation of biomolecules in explicit solvent.

Identification and engineering a C4-dicarboxylate transporter for improvement of malic acid production in Aspergillus niger.

Modification of C4-dicarboxylate transport processes is an important strategy for the development of efficient malic acid producing cell factory in Aspergillus niger. However, there is a lack of identification and functional research of malic acid transport proteins, which seriously hinders the construction of high-yield malic acid metabolic engineering strains. A C4-dicarboxylate transport protein (DCT) DCT1 is identified as major malic acid transport protein and exhibits significant elevation in malic acid production when overexpressed. DCT1 is found by homology searches and domain analyses with SpMAE1 from Schizosaccharomyces pombe as the template. Phylogenetic and domain analyses show that DCTs belong to voltage-dependent slow-anion channel transporter (SLAC1) family and are members of Tellurite-resistance/Dicarboxylate Transporter (TDT) Family. DCT1 disruption dramatically decreases malic acid titer by about 85.6% and 96.2% at 3 days and 5 days compared with the parent strain, respectively. Meanwhile, the citric acid titers increase by 36.4% and 13.7% at 3 days and 5 days upon DCT1 deficiency. These results suggest that DCT1 is the major malic acid transporter in A. niger. Overexpression of dct1 with its native promoter significantly improves malic acid production yielding up to 13.86 g/L and 30.79 g/L at 3 days and 5 days, respectively, which is 36.8% and 22.8% higher than those in the parent strain. However, the citric acid has no significant change during the 5-day fermentation. These results demonstrate the importance of C4-dicarboxylate transporters for the efficient production of malic acid. Furthermore, enhancement of malic acid transport process is a feasible approach of efficient malic acid production in this citric acid producing A. niger strain. KEY POINTS: • A dicarboxylate transporter DCT1 is identified as a major malic acid transporter. • DCT1 deficiency results in significant decrease of malic acid. • DCT1 overexpression leads to increased titers of malic acid. • Enhancement of malic acid transport is vital for malic acid production in A. niger.

Short DNA Hairpins Compromise Recombinant Adeno-Associated Virus Genome Homogeneity.

Short hairpin (sh)RNAs delivered by recombinant adeno-associated viruses (rAAVs) are valuable tools to study gene function in vivo and a promising gene therapy platform. Our data show that incorporation of shRNA transgenes into rAAV constructs reduces vector yield and produces a population of truncated and defective genomes. We demonstrate that sequences with hairpins or hairpin-like structures drive the generation of truncated AAV genomes through a polymerase redirection mechanism during viral genome replication. Our findings reveal the importance of genomic secondary structure when optimizing viral vector designs. We also discovered that shDNAs could be adapted to act as surrogate mutant inverted terminal repeats (mTRs), sequences that were previously thought to be required for functional self-complementary AAV vectors. The use of shDNAs as artificial mTRs opens the door to engineering a new generation of AAV vectors with improved potency, genetic stability, and safety for both preclinical studies and human gene therapy.

Efficient and Targeted Transduction of Nonhuman Primate Liver With Systemically Delivered Optimized AAV3B Vectors.

Recombinant adeno-associated virus serotype 3B (rAAV3B) can transduce cultured human liver cancer cells and primary human hepatocytes efficiently. Serine (S)- and threonine (T)-directed capsid modifications further augment its transduction efficiency. Systemically delivered capsid-optimized rAAV3B vectors can specifically target cancer cells in a human liver cancer xenograft model, suggesting their potential use for human liver-directed gene therapy. Here, we compared transduction efficiencies of AAV3B and AAV8 vectors in cultured primary human hepatocytes and cancer cells as well as in human and mouse hepatocytes in a human liver xenograft NSG-PiZ mouse model. We also examined the safety and transduction efficacy of wild-type (WT) and capsid-optimized rAAV3B in the livers of nonhuman primates (NHPs). Intravenously delivered S663V+T492V (ST)-modified self-complementary (sc) AAV3B-EGFP vectors led to liver-targeted robust enhanced green fluorescence protein (EGFP) expression in NHPs without apparent hepatotoxicity. Intravenous injections of both WT and ST-modified rAAV3B.ST-rhCG vectors also generated stable super-physiological levels of rhesus chorionic gonadotropin (rhCG) in NHPs. The vector genome predominantly targeted the liver. Clinical chemistry and histopathology examinations showed no apparent vector-related toxicity. Our studies should be important and informative for clinical development of optimized AAV3B vectors for human liver-directed gene therapy.

Long-term, efficient inhibition of microRNA function in mice using rAAV vectors.

Understanding the function of individual microRNA (miRNA) species in mice would require the production of hundreds of loss-of-function strains. To accelerate analysis of miRNA biology in mammals, we combined recombinant adeno-associated virus (rAAV) vectors with miRNA 'tough decoys' (TuDs) to inhibit specific miRNAs. Intravenous injection of rAAV9 expressing anti-miR-122 or anti-let-7 TuDs depleted the corresponding miRNA and increased its mRNA targets. rAAV producing anti-miR-122 TuD but not anti-let-7 TuD reduced serum cholesterol by >30% for 25 weeks in wild-type mice. High-throughput sequencing of liver miRNAs from the treated mice confirmed that the targeted miRNAs were depleted and revealed that TuDs induced miRNA tailing and trimming in vivo. rAAV-mediated miRNA inhibition thus provides a simple way to study miRNA function in adult mammals and a potential therapy for dyslipidemia and other diseases caused by miRNA deregulation.

GK921, a transglutaminase inhibitor, strengthens the antitumor effect of cisplatin on pancreatic cancer cells by inhibiting epithelial-to-mesenchymal transition.

Pancreatic adenocarcinoma (PAAD), a common digestive malignant tumor, presents high mortality rates and limited treatment methods. Currently, chemotherapy remains the main therapy method for patients with PAAD. As a classical chemotherapy drug, cisplatin (DDP) is limited by dose-related toxicity in patients with PAAD. In this study, we demonstrated that TGM2 may be a treatment and prognosis marker in pancreatic cancer patients. Co-treatment of low dose of DDP and GK921, a transglutaminase (TGM2) inhibitor, is capable of synergistically inhibiting the PAAD cell viability and proliferation in vitro and in vivo. Based on in vitro study, GK921 inhibited the epithelial-to-mesenchymal transition (EMT) induced by TGM2 as well as aggravated cell cycle arrest and apoptosis resulted from DDP, making pancreatic cancer cells more sensible to DDP. Our results showed that GK921 increased the protein levels regarding E-cadherin as well as decreased the protein level regarding Snail2, N-cadherin, which indicated that GK921 inhibited EMT in pancreatic cancer cells. Snail2 overexpression inhibited GK921/DDP-induced cell apoptosis, as well as mitigated the GK921/DDP-caused cell death and the EMT inhibition. In vivo studies also found GK921/DDP combination can further inhibit the growth of PAAD without significantly side effects. To sum up, we showed that GK921 increased PAAD cells sensitivity to DDP via inhibiting EMT. As revealed, DDP/GK921 co-treatment could promisingly serve for treating PAAD patients.

Structural characterization and anti-oxidant activity of polysaccharide HVP-1 from Volvariella volvacea.

In this study, a novel homogeneous polysaccharide (HVP-1) was purified from the Volvariella volvacea. Its structural characteristics and anti-oxidant activity in vitro were further evaluated. The results revealed that HVP-1 was composed of mannose, glucose, galactose and arabinose in a molar ratio (mol %) of 55.37: 15.74: 25.20: 3.69. Its main chain consisted of →4)-ß-D-Galp-(1→, →6)-α-D-Glcp-(1→, →3)-α-D-Glcp-(1→, →4)-ß-D-Manp-(1→ and →3,6)-ß-D-Manp-(1→. The branched structure α-L-Araf-(1→, →2)-ß-D-Glcp-(1→ and →6)-ß-D-Manp-(1→ were connected to →3,6)-ß-D-Manp-(1→ through the O-3 position. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that HVP-1 had porous sheet-like structure with a triple helix conformation. Anti-oxidant activity experiments showed that HVP-1 alleviated H2O2-induced oxidative damage by reducing the accumulation of reactive oxygen species, increasing the activity of related enzymes in cells, and activating the Nrf2/HO-1 signaling pathway. These results suggested that HVP-1 had the potential to be used as a natural anti-oxidant in functional foods and pharmaceuticals.

Novel Anion-Doped Cathode Material SrFe1-x Si x O3-δF y for Intermediate-Temperature Solid Oxide Fuel Cells.

SrFe1-x Si x O3-δF y cathode materials (x = 0.05, 0.1, 0.15; y = 0, 0.1, 0.5) were prepared via a solid-state method. X-ray diffraction results show that the synthesized F doping samples were perovskite structure. X-ray photoelectron spectroscopy findings show that F- anions were doped into SrFe1-x Si x O3-δ. Transmission electron microscopy and energy-dispersive spectroscopy were performed to analyze the microstructure and element distribution in the materials, respectively. Double-layer composite cathode symmetric cells were prepared through a screen printing method. Scanning electron microscopy images revealed that the double-layer composite cathode adhered well to the electrolyte. The doping with F- can increase the coefficient of thermal expansion of SrFe1-x Si x O3-δ. The electrochemical impedance spectroscopy results indicate that the oxygen transport capacity of the SrFe0.95Si0.05O3-δ material can be improved by doping with F-, but such a method can decrease the oxygen transport capacity of SrFe0.9Si0.1O3-δ. At 800 °C, the peak power density of the single cell supported by an anode and SrFe0.9Si0.1O3-δF0.1 as the cathode reached 388.91 mW/cm2. Thus, the incorporation of F- into SrFe1-x Si x O3-δ cathode materials can improve their electrochemical performance and enable their application as cathode materials for solid-oxide fuel cells.

Cortisol Sensitizes Cochlear Hair Cells to Gentamicin Ototoxicity Via Endogenous Apoptotic Pathway.

BACKGROUND: The widespread use of aminoglycosides is a prevalent cause of sensorineural hearing loss. Patients receiving aminoglycosides usually have elevated levels of circulating stress hormones due to disease or physiological stress; however, whether the stress hormone cortisol impacts aminoglycoside-mediated injury of cochlear hair cells has not been fully investigated. METHODS: House Ear Institute-Organ of Corti 1 (HEI-OC1) cells with or without cortisol pretreatment were exposed to gentamicin, we investigated the effect of cortisol pretreatment on gentamicin ototoxicity by assessing cell viability. Molecular pathogenesis was explored by detecting apoptosis and oxidative stress. Meanwhile, by inhibiting glucocorticoid receptors (GR) and mineralocorticoid receptors (MR), the potential roles of receptor types in cortisol-mediated sensitization were evaluated. RESULTS: Cortisol concentrations below 75 µmol/l did not affect cell viability. However, pretreatment with 50 µmol/l cortisol for 24 hours sensitized hair cells to gentamicin-induced apoptosis. Further mechanistic studies revealed that cortisol significantly increased hair cell apoptosis and oxidative stress, and altered apoptosis-related protein expressions induced by gentamicin. In addition, blockade of either GR or MR attenuated cortisol-induced hair cell sensitization to gentamicin toxicity. CONCLUSION: Cortisol pretreatment increased mammalian hair cell susceptibility to gentamicin toxicity. Sensitization was related to the activation of the intrinsic apoptotic pathway and excessive generation of reactive oxygen species. Cortisol may exacerbate aminoglycoside ototoxicity.