MHY446 induces apoptosis via reactive oxygen species-mediated endoplasmic reticulum stress in HCT116 human colorectal cancer cells.

This study investigated the potential of a newly synthesized histone deacetylase (HDAC) inhibitor, MHY446, in inducing cell death in HCT116 colorectal cancer cells and compared its activity with that of suberoylanilide hydroxamic acid (SAHA), a well-known HDAC inhibitor. The results showed that MHY446 increased the acetylation of histones H3 and H4 and decreased the expression and activity of HDAC proteins in HCT116 cells. Additionally, MHY446 was confirmed to bind more strongly to HDAC1 than HDAC2 and inhibit its activity. In vivo experiments using nude mice revealed that MHY446 was as effective as SAHA in inhibiting HCT116 cell-grafted tumor growth. This study also evaluated the biological effects of MHY446 on cell survival and death pathways. The reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) confirmed that ROS play a role in MHY446-induced cell death by reducing poly(ADP-ribose) polymerase cleavage. MHY446 also induced cell death via endoplasmic reticulum (ER) stress by increasing the expression of ER stress-related proteins. NAC treatment decreased the expression of ER stress-related proteins, indicating that ROS mediate ER stress as an upstream signaling pathway and induce cell death. While MHY446 did not exhibit superior HDAC inhibition efficacy compared to SAHA, it is anticipated to provide innovative insights into the future development of therapeutic agents for human CRC by offering novel chemical structure-activity relationship-related information.

Approaches for 3D Integration Using Plasma-Enhanced Atomic-Layer-Deposited Atomically-Ordered InGaZnO Transistors with Ultra-High Mobility.

As the scale-down and power-saving of silicon-based channel materials approach the limit, oxide semiconductors are being actively researched for applications in 3D back-end-of-line integration. For these applications, it is necessary to develop stable oxide semiconductors with electrical properties similar to those of Si. Herein, a single-crystal-like indium-gallium-zinc-oxide (IGZO) layer (referred to as a pseudo-single-crystal) is synthesized using plasma-enhanced atomic layer deposition and fabricated stable IGZO transistors with an ultra-high mobility of over 100 cm2  Vs-1 . To acquire high-quality atomic layer deposition-processed IGZO layers, the plasma power of the reactant is controlled as an effective processing parameter by evaluating and understanding the effect of the chemical reaction of the precursors on the behavior of the residual hydrogen, carbon, and oxygen in the as-deposited films. Based on these insights, this study found that there is a critical relationship between the optimal plasma reaction energy, superior electrical performance, and device stability.

Selectively Nitrogen Doped ALD-IGZO TFTs with Extremely High Mobility and Reliability.

Achieving high mobility and reliability in atomic layer deposition (ALD)-based IGZO thin-film transistors (TFTs) with an amorphous phase is vital for practical applications in relevant fields. Here, we suggest a method to effectively increase stability while maintaining high mobility by employing the selective application of nitrous oxide plasma reactant during plasma-enhanced ALD (PEALD) at 200 °C process temperature. The nitrogen-doping mechanism is highly dependent on the intrinsic carbon impurities or nature of each cation, as demonstrated by a combination of theoretical and experimental research. The Ga2O3 subgap states are especially dependent on plasma reactants. Based on these insights, we can obtain high-performance indium-rich PEALD-IGZO TFTs (threshold voltage: -0.47 V; field-effect mobility: 106.5 cm2/(V s); subthreshold swing: 113.5 mV/decade; hysteresis: 0.05 V). In addition, the device shows minimal threshold voltage shifts of +0.45 and -0.10 V under harsh positive/negative bias temperature stress environments (field stress: ±2 MV/cm; temperature stress: 95 °C) after 10000 s.

Enhanced performance and stability in InGaZnO NIR phototransistors with alumina-infilled quantum dot solid.

The optimized ALD infilling process for depositing Al2O3 in the vertical direction of PbS QDs enhances the photoresponsivity, relaxation rate and the air stability of PbS QDs hybrid IGZO NIR phototransistors. Infilled Al2O3, which is gradually deposited from the top of PbS QDs to the PbS/IGZO interface (1) passivates the trap sites up to the interface of PbS/IGZO without disturbing charge transfer and (2) prevents QDs deterioration caused by outside air. Therefore, an Al2O3 infilled PbS QD/IGZO hybrid phototransistor (AI-PTs) exhibited enhanced photoresponsivity from 96.4 A/W to 1.65 × 102 A/W and a relaxation time decrease from 0.52 to 0.03 s under NIR light (880 nm) compared to hybrid phototransistors without Al2O3 (RF-PTs). In addition, AI-PTs also showed improved shelf stability over 4 months compared to RF-PTs. Finally, all devices we manufactured have the potential to be manufactured in an array, and this ALD technique is a means of fabricating robust QDs/metal oxide hybrids for optoelectronic devices.

Microvirga terrestris sp. nov., and Microvirga arvi sp. nov., isolated from soil in South Korea.

Two novel Gram-stain-negative, aerobic, rod shaped bacterial strains BT290T and BT689T were isolated from soil collected in South Korea. Colony morphologies of both strains were circular and convex while the colors of BT290T and BT689T were light-pink and white, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that BT290T and BT689T belong to a distinct lineage within the genus Microvirga (family Methylobacteriaceae, order Rhizobiales, class Alphaproteobacteria, phylum Proteobacteria, kingdom Bacteria). The 16S rR NA gene sequence similarity between two strains was 97.9%. Both strains had the similar quinone system, with ubiquinone 10 (Q-10) as the major respiratory quinone. The major polar lipids of strains BT290T and BT689T were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), phosphatidylcholine (PC), and phosphatidylglycerol (PG). The major cellular fatty acids of strain BT290T were C18:1 ω7c (58.2%) and C16:0 (17.7%), while those of strain BT689T were C18:1 ω7c (61.8%) and C16:0 (10.8%). On the bases of polyphasic analysis (phylogenetic, chemotaxonomic, and biochemical), strains BT290T and BT689T can be suggested as novel bacterial species within the genus Microvirga and the proposed names are Microvirga terrestris and Microvirga arvi, respectively. The type strain of Microvirga terrestris is BT290T (= KCTC 72367T = NBRC 114844T) and the type strain of Microvirga arvi is BT689T (= KACC 22016T = NBRC 114858T), respectively.

Hymenobacter telluris sp. nov., isolated from soil in South Korea.

Two novel bacterial strains, designated as BT186T and BT505, were isolated from a soil sample collected in South Korea and characterized. Both strains were Gram-stain-negative, rod-shaped, aerobic, circular, convex, and had red-colored colonies. The level of 16S rRNA gene sequence similarity between the strains BT186T and BT505 was 100%, indicating that they represent an identical species. 16S rRNA sequence analysis indicated that strains BT186T and BT505 belong to a distinct lineage within the genus Hymenobacter (family Hymenobacteraceae, order Cytophagales, class Cytophagia, phylum Bacteroidetes, Kingdom Bacteria). Both strains were closely related to Hymenobacter norwichensis DSM 15439T (98.3% 16S rRNA gene similarity), Hymenobacter aquaticus JCM 31653T (96.8%), and Hymenobacter perfusus LMG26000T (96.5%). Strain BT186T was found to have the MK-7 as the major respiratory quinone. The major polar lipid of strain BT186T was identified to be phosphatidylethanolamine (PE). The major cellular fatty acid profiles of strain BT186T were C16:1 ω5c (24.3%), iso-C15:0 (20.3%) and summed feature 3 (C16:1 ω6c/C16:1 ω7c) (19.9%). Characterization based on polyphasic analysis indicated that strains BT186T and BT505 represent novel species of the genus Hymenobacter and the name Hymenobacter telluris sp. nov. is proposed. The type strain of Hymenobacter telluris is BT186T (= KCTC 72338T = NBRC 114968T).

Preparation and Electrochemical Analysis of Ni-Based Metal Organic Frameworks Containing Binary Ligands for Capacitor Electrodes.

As one of the energy storage systems, supercapacitors have quite long charge-discharge cycle life. Among many kinds of electrode materials, metal organic frameworks (MOFs) have unique properties such as high specific surface areas and large pore volume as supercapacitor electrode materials. Nickel-MOFs consist of binary ligand such as 1,3,5-Trimesic acid (H3BTC) and terephthalic acid (TPA) were used as working electrode materials in three electrode cell for capacitor system. When synthesizing MOFs, it is possible to prepare uniform crystals using hydrothermal synthesis. The morphology of composites was analyzed by field emission scanning electron microscopy (FE-SEM). Electrochemical properties were measured by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) in 6M KOH electrolyte.

Novel SIRT Inhibitor, MHY2256, Induces Cell Cycle Arrest, Apoptosis, and Autophagic Cell Death in HCT116 Human Colorectal Cancer Cells.

We examined the anticancer effects of a novel sirtuin inhibitor, MHY2256, on HCT116 human colorectal cancer cells to investigate its underlying molecular mechanisms. MHY2256 significantly suppressed the activity of sirtuin 1 and expression levels of sirtuin 1/2 and stimulated acetylation of forkhead box O1, which is a target protein of sirtuin 1. Treatment with MHY2256 inhibited the growth of the HCT116 (TP53 wild-type), HT-29 (TP53 mutant), and DLD-1 (TP53 mutant) human colorectal cancer cell lines. In addition, MHY2256 induced G0/G1 phase arrest of the cell cycle progression, which was accompanied by the reduction of cyclin D1 and cyclin E and the decrease of cyclin-dependent kinase 2, cyclin-dependent kinase 4, cyclin-dependent kinase 6, phosphorylated retinoblastoma protein, and E2F transcription factor 1. Apoptosis induction was shown by DNA fragmentation and increase in late apoptosis, which were detected using flow cytometric analysis. MHY2256 downregulated expression levels of procaspase-8, -9, and -3 and led to subsequent poly(ADP-ribose) polymerase cleavage. MHY2256-induced apoptosis was involved in the activation of caspase-8, -9, and -3 and was prevented by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, the autophagic effects of MHY2256 were observed as cytoplasmic vacuolation, green fluorescent protein-light-chain 3 punctate dots, accumulation of acidic vesicular organelles, and upregulated expression level of light-chain 3-II. Taken together, these results suggest that MHY2256 could be a potential novel sirtuin inhibitor for the chemoprevention or treatment of colorectal cancer or both.

ER stress contributes to autophagy induction by adiponectin in macrophages: Implication in cell survival and suppression of inflammatory response.

Adiponectin, the most abundant adipokine, exhibits various physiological functions. In addition to its critical role in lipid metabolism, recent studies have demonstrated its potent anti-inflammatory and cytoprotective properties. Accumulating evidence suggests that autophagy plays a critical role in various biological responses by adiponectin. However, the underlying mechanisms remain elusive. Herein, we investigated the role of ER stress in adiponectin-induced autophagy and its functional roles in biological responses by adiponectin in macrophages. In this study, globular adiponectin (gAcrp) significantly increased the expression of various ER stress markers in both RAW 264.7 and primary peritoneal macrophages. In addition, inhibition of ER stress by treatment with tauroursodeoxycholic acid (TUDCA) or gene silencing of CHOP prominently suppressed gAcrp-induced autophagy. Treatment with gAcrp also induced significant increase in sestrin2 expression. Interestingly, knockdown of sestrin2 prevented autophagy induction and inhibition of ER stress abrogated sestrin2 induction by gAcrp, collectively implying that ER stress critically contributes to gAcrp-induced autophagy activation via sestrin2 induction. Moreover, pretreatment with TUDCA restored suppression of TNF-α and IL-1ß expression and attenuated the enhanced viability of macrophages induced by gAcrp. Taken together, these findings indicate the potential role of ER stress in autophagy activation, modulation of inflammatory responses, and cell survival by gAcrp in macrophages.

The Association between 10-Year Atherosclerotic Cardiovascular Diseases Risk Score Calculated Using 2013 American College of Cardiology/American Heart Association Guidelines and Serum 25-Hydroxyvitamin D Level among Aged 40-79 Years in Korea: The Sixth Korea National Health and Nutrition Examination Surveys.

BACKGROUND: We examined the relationship between 10-year predicted atherosclerosis cardiovascular disease (ASCVD) risk score and 25-hydroxyvitamin D in Koreans aged 40-79 years. METHODS: A population-based, cross-sectional design was used from data based on the Korea National Health and Nutrition Examination Survey 2014. RESULTS: A total of 1,134 healthy Koreans aged 40-79 years were included. A positive relationship between serum 25-hydroxyvitamin D level and ASCVD score was shown in women (ß=0.015) after adjusting for central obesity, physical activity, and supplement intake. The chances of being in the moderate to high risk (risk group, ASCVD score ≥5%) with vitamin D sufficiency (serum 25-hydroxyvitamin D ≥20 ng/mL) was 1.267-fold (95% confidence interval, 1.039-1.595) greater than the chance of being included in the group with vitamin D deficiency (serum 25-hydroxyvitamin D <20 ng/mL) after adjustments in women. CONCLUSION: Our research indicated a significantly positive association between 25-hydroxyvitamin D and ASCVD score. Further detailed studies to evaluate this correlation are needed.

YJI-7 Suppresses ROS Production and Expression of Inflammatory Mediators via Modulation of p38MAPK and JNK Signaling in RAW 264.7 Macrophages.

Chalcone, (2E)-1,3-Diphenylprop-2-en-1-one, and its synthetic derivatives are known to possess anti-oxidative and anti-inflammatory properties. In the present study, we prepared a novel synthetic chalcone compound, (E)-1-(4-hydroxyphenyl)-3-(2-(trifluoromethoxy)phenyl)prop-2-en-1-one name (YJI-7), and investigated its inhibitory effects on endotoxin-stimulated production of reactive oxygen species (ROS) and expression of inflammatory mediators in macrophages. We demonstrated that treatment of RAW 264.7 macrophages with YJI-7 significantly suppressed lipopolysaccharide (LPS)-stimulated ROS production. We also found that YJI-7 substantially decreased NADPH oxidase activity stimulated by LPS, indicating that YJI-7 regulates ROS production via modulation of NADPH oxidase in macrophages. Furthermore, YJI-7 strongly inhibited the expression of a number of inflammatory mediators in a gene-selective manner, suggesting that YJI-7 possesses potent anti-inflammatory properties, as well as anti-oxidative activity. In continuing experiments to investigate the mechanisms that could underlie such biological effects, we revealed that YJI-7 suppressed phosphorylation of p38MAPK and JNK stimulated by LPS, whereas no significant effect on ERK was observed. Furthermore, LPS-stimulated production of ROS, activation of NADPH oxidase and expression of inflammatory mediators were markedly suppressed by treatment with selective inhibitor of p38MAPK (SB203580) and JNK (SP600125). Taken together, these results demonstrated that YJI-7, a novel synthetic chalcone derivative, suppressed LPS-stimulated ROS production via modulation of NADPH oxidase and diminished expression of inflammatory mediators, at least in part, via down-regulation of p38MAPK and JNK signaling in macrophages.

MHY451 induces cell cycle arrest and apoptosis by ROS generation in HCT116 human colorectal cancer cells.

Colorectal cancer (CRC) is the third most frequently diagnosed cancer and cause of cancer-related deaths. Despite advancements in conventional therapeutic approaches to CRC, most patients with CRC die of their disease. There is a need to develop novel therapeutic agents for this malignancy. Therefore, the present study aimed to examine the anticancer effects and elucidate the underlying mechanism of MHY451 in HCT116 human colorectal cancer cells. Treatment with MHY451 inhibited cell growth in a time- and concentration-dependent manner. MHY451 increased the accumulation of cell cycle progression at the G2/M phase. This agent decreased the protein level of cyclin B1 and its activating partners, Cdc25c and Cdc2, whereas it increased the cell cycle inhibitor p21WAF/CIP. The induction of apoptosis was observed by decreased viability, cleavage of poly(ADP-ribose) polymerase (PARP), alteration in the ratio of Bax/Bcl-2 protein expression and reduction of procaspase-8 and -9. Pretreatment with Z-VAD-FMK, a pan-caspase inhibitor, inhibited MHY451-induced apoptosis, indicating that apoptotic cell death by MHY451 was mediated through caspases. Moreover, the apoptotic effect of MHY451 was reactive oxygen species (ROS)-dependent, evidenced by the inhibition of MHY451-induced PARP cleavage and ROS generation by N-acetylcysteine-induced ROS scavenging. Taken together, these results demonstrate that MHY451 exerts anticancer effects by regulating the cell cycle, inducing apoptosis through caspase activation and generating ROS. These results suggest that MHY451 has considerable potential for chemoprevention or treatment of CRC or both.

Inhibition of LPS-stimulated ROS production by fluorinated and hydroxylated chalcones in RAW 264.7 macrophages with structure-activity relationship study.

Based on the importance of the previous fluorinated and/or hydroxylated chalcones studies, thirty-six compounds were designed as phenyl or hydroxyphenyl bearing fluoro, trifluoromethyl or trifluoromethoxy phenyl propenones and synthesized by applying modified Claisen-Schmidt condensation reaction as a single step. Inhibitory effects of the synthesized compounds on ROS production stimulated by LPS in RAW 264.7 macrophage were evaluated. Structure-activity relationship (SAR) study revealed that the compounds possessing para-hydroxyphenyl group combined with meta-fluoro or meta-trifluoromethyl phenyl group, and meta/para-hydroxyphenyl group combined with ortho-trifluoromethoxyphenyl group have an essential role in inhibiting the LPS-stimulated ROS production in RAW 264.7 macrophages. The most significant inhibitory effect on LPS-stimulated ROS production in RAW 264.7 macrophages was observed in compound 30 that possessed para-hydroxyphenyl group along with ortho-trifluoromethoxyphenyl group.

Serum 25-Hydroxyvitamin D3 and BAFF Levels Are Associated with Disease Activity in Primary Sjogren's Syndrome.

The study investigated the association between disease activity and serum 25-hydroxyvitamin D3 (25(OH)-D3), B cell activation of the tumor necrosis factor family (BAFF), or ß2 microglobulin in patients with primary Sjogren's syndrome (SS). Sixty-nine primary SS patients and 22 sicca control patients were included in the study. Disease activity was measured with EULAR Sjogren's syndrome disease activity index (ESSDAI). Serum levels of 25(OH)-D3 and ß2 microglobulin were measured by radioimmunoassay and BAFF was measured by an enzyme-linked immunosorbent assay. Serum levels of 25(OH)-D3 were significantly lower in SS patients compared to the sicca controls (p = 0.036). Serum levels of BAFF tended to be higher (p = 0.225) and those of ß2 microglobulin were significantly higher in patients with SS than in sicca controls (p = 0.023). In univariate regression analyses, ESSDAI was significantly associated with serum levels of 25(OH)-D3, BAFF, and ß2 microglobulin. After stepwise backward multivariate linear regression analyses including age and acute phase reactants, ESSDAI was associated with 25(OH)-D3 (ß = -0.042, p = 0.015) and BAFF (ß = 0.001, p = 0.015) in SS patients. In SS patients, ESSDAI is negatively associated with serum levels of 25(OH)-D3 and positively associated with BAFF.

Prevalence and clinical impact of fibromyalgia in patients with primary Sjögren's syndrome.

OBJECTIVES: Clinical features of primary Sjögren's syndrome (pSS) overlap with those of fibromyalgia (FM). This cross-sectional study was conducted to investigate the prevalence of FM in pSS patients and to compare the clinical features of pSS patients with FM to those without FM. METHODS: One hundred pSS patients were consecutively assessed to identify the presence of FM according to the American College of Rheumatology (ACR) 2010 criteria. Clinical and laboratory data were collected from all patients. Additional assessments included EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) and EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI). The severity of depression was measured by Hamilton depression rating scale 17-items (HAM-D scale). RESULTS: The prevalence of FM was 31.0% (31/100) in pSS. Widespread pain index and symptom severity scale were significantly correlated with ESSPRI (r=0.6542 and r=0.7173, both p<0.0001) and HAM-D scale (r=0.6734 and r=0.6471, both p<0.0001) in pSS. In multivariate analysis, ESSPRI and HAM-D scale were independently associated with increase of tender point count and symptom severity scale. ESSPRI was significantly higher in pSS patients with FM compared to those without FM (p<0.0001). The prevalence of FM in pSS patients with moderate-to-severe depression was significantly higher than those with mild depression or without depression (odds ratio= 10.62, p=0.0009). Serum 25-hydroxy vitamin D3 levels in pSS patients with FM were significantly (p=0.0072) decreased compared to those without FM. CONCLUSIONS: Our study showed that FM was prevalent in pSS. FM was associated with higher ESSPRI and more severe depression.

Unveiling of novel regio-selective fatty acid double bond hydratases from Lactobacillus acidophilus involved in the selective oxyfunctionalization of mono- and di-hydroxy fatty acids.

The aim of this study is the first time demonstration of cis-12 regio-selective linoleate double-bond hydratase. Hydroxylation of fatty acids, abundant feedstock in nature, is an emerging alternative route for many petroleum replaceable products thorough hydroxy fatty acids, carboxylic acids, and lactones. However, chemical route for selective hydroxylation is still quite challenging owing to low selectivity and many environmental concerns. Hydroxylation of fatty acids by hydroxy fatty acid forming enzymes is an important route for selective biocatalytic oxyfunctionalization of fatty acids. Therefore, novel fatty acid hydroxylation enzymes should be discovered. The two hydratase genes of Lactobacillus acidophilus were identified by genomic analysis, and the expressed two recombinant hydratases were identified as cis-9 and cis-12 double-bond selective linoleate hydratases by in vitro functional validation, including the identification of products and the determination of regio-selectivity, substrate specificity, and kinetic parameters. The two different linoleate hydratases were the involved enzymes in the 10,13-dihydroxyoctadecanoic acid biosynthesis. Linoleate 13-hydratase (LHT-13) selectively converted 10 mM linoleic acid to 13S-hydroxy-9(Z)-octadecenoic acid with high titer (8.1 mM) and yield (81%). Our study will expand knowledge for microbial fatty acid-hydroxylation enzymes and facilitate the designed production of the regio-selective hydroxy fatty acids for useful chemicals from polyunsaturated fatty acid feedstocks.

Determination of EC95 of remifentanil for smooth emergence from propofol anesthesia in patients undergoing transsphenoidal surgery.

BACKGROUND: In patients undergoing pituitary surgery using a transsphenoidal approach, anesthesia emergence should be smooth with minimal coughing. Recent studies demonstrated that a target-controlled infusion of remifentanil effectively suppresses coughing induced by the endotracheal tube. We investigated the EC95 of remifentanil for smooth emergence without coughing from propofol anesthesia in patients undergoing transsphenoidal hypophysectomy. MATERIALS AND METHODS: A total of 41 patients undergoing transsphenoidal hypophysectomy, aged 20 to 65 years, with an ASA physical status of I or II, were enrolled. For all participants, anesthesia was induced and maintained with a target-controlled infusion of remifentanil and propofol using predicted effect-site concentration (Ce). A biased coin design up-and-down sequential allocation and isotonic regression method were used to determine the remifentanil EC95 to prevent emergence coughing. In addition, we observed recovery profiles after anesthesia. RESULTS: According to the study design, 19 patients received remifentanil 2.6 ng/mL Ce and 22 patients received a lower Ce, ranging from 1.0 to 2.2 ng/mL. The EC95 of remifentanil to prevent coughing was estimated as 2.51 ng/mL (95% confidence interval, 2.28-2.57 ng/mL). Despite the exclusion of 1 case because of delayed emergence, 17 of 18 patients receiving 2.6 ng/mL of remifentanil had bradypnea (<10 breaths/min) until 3 minutes after extubation. However, end-tidal carbon dioxide was maintained below 55 mm Hg during anesthetic emergence and respiratory rate recovered within 20 minutes of admission to the postanesthetic care unit. CONCLUSIONS: The EC95 of remifentanil for smooth emergence from anesthesia was 2.51 ng/mL after transsphenoidal hypophysectomy.

Highly selective hydrolysis for the outer glucose at the C-20 position in ginsenosides by ß-glucosidase from Thermus thermophilus and its application to the production of ginsenoside F2 from gypenoside XVII.

ß-Glucosidase from Thermus thermophilus has specific hydrolytic activity for the outer glucose at the C-20 position in protopanaxadiol-type ginsenosides without hydrolysis of the inner glucose. The hydrolytic activity of the enzyme for gypenoside XVII was optimal at pH 6.5 and 90 °C, with a half-life of 1 h with 3 g enzyme l(-1) and 4 g gypenoside XVII l(-1). Under the optimized conditions, the enzyme converted the substrate gypenoside XVII to ginsenoside F2 with a molar yield of 100 % and a productivity of 4 g l(-1) h(-1). The conversion yield and productivity of ginsenoside F2 are the highest reported thus far among enzymatic transformations.

Production of ginsenosides Rg1 and Rh1 by hydrolyzing the outer glycoside at the C-6 position in protopanaxatriol-type ginsenosides using ß-glucosidase from Pyrococcus furiosus.

The specific activity of a recombinant ß-glucosidase from Pyrococcus furiosus for protopanaxatriol (PPT)-type ginsenosides followed the order Rf > R1 > Re > R2 > Rg2, which were converted to Rh1, Rg1, Rg1, Rh1, and Rh1, respectively. No activity was observed with Rg1 and Rh1. Thus, P. furiosus ß-glucosidase hydrolyzed the outer glycoside at the C-6 position in PPT-type ginsenosides whereas the enzyme did not hydrolyze the inner glucoside at the C-6 position and the glucoside at the C-20 position. The activity for Rf was optimal at 95 °C, pH 5.5, 5 mM ginsenoside, and 32 U enzyme l−1. Under these conditions, P. furiosus ß-glucosidase completely converted from R1 to Rg1 after 10 h, with a productivity of 0.4 g l−1 h−1 and completely converted Rf to Rh1 after 1.2 h, with a productivity of 2.74 g l−1 h−1.

Pharmacological activation of Sirt1 ameliorates polyglutamine-induced toxicity through the regulation of autophagy.

Intracellular accumulation of polyglutamine (polyQ)-expanded Huntingtin (Htt) protein is a hallmark of Huntington's disease (HD). This study evaluated whether activation of Sirt1 by the anti-cancer agent, ß-lapachone (ß-lap), induces autophagy in human neuroblastoma SH-SY5Y cells, thereby reducing intracellular levels of polyQ aggregates and their concomitant cytotoxicity. Treatment of cells with ß-lap markedly diminished the cytotoxicity induced by forced expression of Htt exon 1 containing a pathogenic polyQ stretch fused to green fluorescent protein (HttEx1(97Q)-GFP). ß-lap increased autophagy in SH-SY5Y cells, as evidenced by the increased formation of LC3-II and autolysosomes. Furthermore, ß-lap reduced HttEx1(97Q)-GFP aggregation, which was significantly prevented by co-incubation with 3-methyladenine, an inhibitor of autophagy. ß-lap increased Sirt1 activity, as shown by the increased deacetylation of the Sirt1 substrates, PARP-1 and Atg5, and the nuclear translocation of FOXO1. Both the induction of autophagy and attenuation of HttEx1(97Q)-GFP aggregation by ß-lap were significantly prevented by co-incubation with sirtinol, a general sirtuin inhibitor or by co-transfection with shRNA against Sirt1. The pro-autophagic actions of ß-lap were further investigated in a transgenic Caenorhabditis elegans (C. elegans) line that expressed Q67 fused to cyanine fluorescent protein (Q67). Notably, ß-lap reduced the number of Q67 puncta and restored Q67-induced defects in motility, which were largely prevented by pre-treatment with RNAi against sir-2.1, the C. elegans orthologue of Sirt1. Collectively, these data suggest that ß-lap induces autophagy through activation of Sirt1, which in turn leads to a reduction in polyQ aggregation and cellular toxicity. Thus, ß-lap provides a novel therapeutic opportunity for the treatment of HD.