36 research outputs found

    Enhancement of carbamazepine removal rate using Tetradesmus obliquus KNUA061 and NaOCl and utilization of the resulting biomass

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    Pharmaceutical and personal care products (PPCPs) are discharged into receiving water bodies mainly from sewage treatment plants. Due to the inefficient removal in conventional wastewater treatment facilities, PPCPs have become a major concern to aquatic ecosystems, water quality, and public health worldwide since they cause harmful effects on aquatic life and human even at low doses. Among the PPCPs, carbamazepine (CBZ) is one of the most commonly prescribed anticonvulsant drugs and consumed more than 1,000 tons per year. Due to its structural complexity, CBZ is known as recalcitrant compound highly stable during wastewater treatment. Consequently, it has become one of the most frequently detected pharmaceuticals in waste water, surface water, and even drinking water. In this study, Korean indigenous microalgae strains were tested as eco-friendly and cost-effective solutions for CBZ removal. Based on the preliminary biological CBZ degradation tests, Tetradesmus obliquus KNUA061 demonstrating the best CBZ removal rate was selected for further experiments. In order to increase strain KNUA061's CBZ removal efficiency, NaOCl, which is widely accepted in the water purification process, was used as an additional stimulus to induce stress conditions. At around 20 μg L−1 CBZ, addition of 1.0 mg NaOCl resulted in approximately 20% of removal rate increase without suppressing cells growth. Roughly 90% of CBZ remained its original form and the composition of the transformed secondary metabolites was less than 10% during the biodegradation process by the microalga. Based on the results of the antioxidant enzyme activities, degree of lipid oxidation, and amino acid contents, it was concluded that the redox-defence system in microalgal cells may have been activated by the NaOCl treatment. Biomass analysis results showed that higher heating value (HHV) of strain KNUA061 biomass was higher than those of lignocellulosic energy crops suggesting that it could be utilized as a possible renewable energy source. Even though its biodiesel properties were slightly below the international standards due to the high PUFA contents, the biodiesel produced from T. obliquus KNUA061 could be used as a blending resource for transportation fuels. It was also determined that the microalgal biomass has acceptable feasibility as a sustainable dietary supplement feedstock due to its high essential amino acid contents

    Caloric restriction of db/db mice reverts hepatic steatosis and body weight with divergent hepatic metabolism

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    Non-alcoholic fatty liver disease (NAFLD) is one of the most frequent causes of liver disease and its prevalence is a serious and growing clinical problem. Caloric restriction (CR) is commonly recommended for improvement of obesity-related diseases such as NAFLD. However, the effects of CR on hepatic metabolism remain unknown. We investigated the effects of CR on metabolic dysfunction in the liver of obese diabetic db/db mice. We found that CR of db/db mice reverted insulin resistance, hepatic steatosis, body weight and adiposity to those of db/m mice. H-NMR- and UPLC-QTOF-MS-based metabolite profiling data showed significant metabolic alterations related to lipogenesis, ketogenesis, and inflammation in db/db mice. Moreover, western blot analysis showed that lipogenesis pathway enzymes in the liver of db/db mice were reduced by CR. In addition, CR reversed ketogenesis pathway enzymes and the enhanced autophagy, mitochondrial biogenesis, collagen deposition and endoplasmic reticulum stress in db/db mice. In particular, hepatic inflammation-related proteins including lipocalin-2 in db/db mice were attenuated by CR. Hepatic metabolomic studies yielded multiple pathological mechanisms of NAFLD. Also, these findings showed that CR has a therapeutic effect by attenuating the deleterious effects of obesity and diabetes-induced multiple complications

    Catalytic Enantioselective Carbon Insertion into the β‑Vinyl C–H Bond of Cyclic Enones

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    Chiral oxazaborolidinium ion-catalyzed C<sub>sp<sup>2</sup></sub>–H functionalization of enones using diazoacetate has been developed. Various β-substituted cyclic enones were synthesized in high yield (up to 99%) with high to excellent enantioselectivity (up to 99% ee). The synthetic utility of this reaction was demonstrated by the formal synthesis of (+)-epijuvabione

    l‑Proline Derived Bifunctional Organocatalysts: Enantioselective Michael Addition of Dithiomalonates to <i>trans</i>-β-Nitroolefins

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    A series of novel l-proline derived tertiary amine bifunctional organocatalysts <b>9</b> are reported, which were applied to the asymmetric Michael addition of dithiomalonates <b>2</b> to <i>trans</i>-β-nitroolefins <b>1</b>. The reaction proceeded in high yields (up to 99%) with high enantioselectivities (up to 97% ee). The synthetic utility of this methodology was demonstrated in the short synthesis of (<i>R</i>)-phenibut in high yield

    Asymmetric Synthesis of α‑Alkylidene-β-hydroxy-γ-butyrolactones via Enantioselective Tandem Michael–Aldol Reaction

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    A simple and efficient method for the asymmetric synthesis of α-alkylidene-β-hydroxy-γ-butyrolactones and related natural products was developed on the basis of the catalytic asymmetric tandem Michael–aldol reaction and simple transformations. The synthetic utility of this method was illustrated by the facile synthesis of trisubstituted γ-butyrolactone natural products

    The <i>Purple leaf</i> (<i>Pl</i>) Alleles, <i>Pl<sup>w</sup></i> and <i>Pl<sup>i</sup></i>, Regulate Leaf Color Development Independently from the <i>Pb</i> Gene of <i>Purple pericarp</i> (<i>Prp</i>) in Rice

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    Color development in various rice organs results from the complementary expression of genes involved in anthocyanin biosynthesis. The Purple pericarp (Prp) trait and the Purple leaf (Pl) trait both display epistasis, relying on the complement of the Pb and Pp genes for pericarp coloration and the Pl and Pp genes for leaf coloration, respectively. However, there is still genetic uncertainty in identifying the genes responsible for the various color expressions and intensities of rice grain pericarp and leaves. In this study, we characterized the inheritance patterns of color development and the mode of anthocyanin pigments in rice by crossing two parental mutant lines. YUM051, exhibiting dark purple leaves (Plw) and purple pericarp (Prp), was crossed with YUM144, which displayed light purple leaves (Pli) and a white pericarp (prp). The F1 plants exhibited dark purple leaves with purple pericarps, indicating the dominant nature of the purple leaf (Pl) and purple pericarp (Prp) traits. The rice Prp traits display a complementary interaction, reflected in a 9:7 ratio of purple to white pericarp. However, the Prp trait followed Mendelian segregation with a 3:1 ratio of purple to white pericarp in this cross, indicating homozygous dominant Pp alleles in both parental plants. Meanwhile, the segregation of the purple leaf color in the F2 generation of this cross followed complementary inheritance, exhibiting a 9:7 segregation ratio between purple leaves and greenish leaves with purple leaf margins. Moreover, the co-segregation of Prp and Pl traits in the cross between YUM051 (Plw) and YUM144 (Pli) plants did not adhere to the Mendelian 9:3:3:1 independent assortment ratio, confirming that the Pl gene and Pb gene are linked on the same chromosome. Cyanidin-3-O-glucoside (C3G) was detected in the leaves of all progeny resulting from the Plw and Pli cross. However, C3G was exclusively identified in the seeds of offspring carrying the dominant Pb gene. Therefore, the Plw and Pli alleles are Pl genes responsible for purple leaf color, while the Pb gene is responsible for purple pericarp color in rice; these genes function independently of each other

    Catalytic Carbon Insertion into the β‑Vinyl C–H Bond of Cyclic Enones with Alkyl Diazoacetates

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    The first example of the boron Lewis acid catalyzed C<sub>sp2</sub>–H functionalization of cyclic enones was achieved using diazoacetates. The insertion of the carbon atom of diazoacetates utilizes BF<sub>3</sub>•Et<sub>2</sub>O or a newly designed oxazaborolidinium ion as a catalyst to afford β-functionalized cyclic enones from simple cyclic enones in a single step and high yields. The reaction mechanism was investigated with deuterium labeled 2-cyclohexen-1-one

    Total Synthsis of (+)-Ambuic Acid: α-Bromination with 1,2-Dibromotetrachloroethane

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    Total synthesis of (+)-ambuic acid has been accomplished from the readily available stereocontrolled Diels–Alder adduct of cyclopentadiene and iodo-1,4-benzoquinone monoketal through an efficient series of steps. A new method for the highly commendable synthesis of α-brominated Diels–Alder adduct is described

    Enantioselective Synthesis of <i>syn</i>-α-Aryl-β-hydroxy Weinreb Amides: Catalytic Asymmetric Roskamp Reaction of α‑Aryl Diazo Weinreb Amides

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    A convenient one-pot procedure to synthesize a variety of highly optically active <i>syn</i>-α-aryl-β-hydroxy Weinreb amides using an asymmetric Roskamp/reduction strategy is described. An oxazaborolidinium ion catalyzed asymmetric Roskamp reaction of α-aryl diazo Weinreb amides with aldehydes produced α-phenyl-β-keto Weinreb amides, which were in situ reduced with zinc borohydride to give <i>syn</i>-α-aryl-β-hydroxy Weinreb amides in good yields (up to 87%) with high enantioselectivities (up to 99% ee) and <i>syn</i> stereoselectivities (>20:1)
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