178 research outputs found

    Tyrosinase inhibitory and antioxidant activity by bromophenols from the alga Odonthalia corymbifera

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    In the course of our search for tyrosinase inhibitors and antioxidants, six known bromophenol dimers were purified from methanol extract of the red alga Odonthalia corymbifera. The compounds were identified by comparison with published spectroscopic data. These bromophenols were categorized into symmetric and asymmetric dimers. Among them, the tetrabrominated dimers displayed more potent tyrosinase inhibition than the tribrominated ones. Especially, the asymmetric tetrabrominated compound showed strong inhibition. These results suggest that number of bromine substitution and orientation of bromine and phenolic hydroxy groups are important factors of tyrosinase inhibitory potency. The bromophenols were also investigated for antioxidant activities by using DPPH and ABTS radical scavenging, CUPRAC and FRAP metal reducing and copper chelation assays. All dimers showed comparable antioxidant activities to the positive controls examined. Symmetric dimers displayed relatively higher antioxidant activities than asymmetric ones

    HEAT RECOVERY FROM MELTED BLAST FURNACE SLAG USING FLUIDIZED BED

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    A novel fluidized bed system is proposed to recover heat from melted blast furnace slag. The melted slag is fed into a fluidized bed of crushed solid slag particles. The heat of slag solidification is transported to immersed heat transfer surface through fluidizing particles. The solid slag clumps, which consist of solidified slag and bed material, are removed from the bottom. A part of the slag clumps are crushed and recycled into the bed as bed material. In the present article, conceptual design of arrangement of heat transfer surface was carried out. Fundamental study of heat recovery from melted wax (simulated melted slag) was conducted using a fluidized bed cold model. Heat balance of the fluidized bed cold model was established

    Substrate size-dependent conformational changes of bacterial pectin-binding protein crucial for chemotaxis and assimilation

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    Gram-negative Sphingomonas sp. strain A1 exhibits positive chemotaxis toward acidic polysaccharide pectin. SPH1118 has been identified as a pectin-binding protein involved in both pectin chemotaxis and assimilation. Here we show tertiary structures of SPH1118 with six different conformations as determined by X-ray crystallography. SPH1118 consisted of two domains with a large cleft between the domains and substrates bound to positively charged and aromatic residues in the cleft through hydrogen bond and stacking interactions. Substrate-free SPH1118 adopted three different conformations in the open form. On the other hand, the two domains were closed in substrate-bound form and the domain closure ratio was changed in response to the substrate size, suggesting that the conformational change upon binding to the substrate triggered the expression of pectin chemotaxis and assimilation. This study first clarified that the solute-binding protein with dual functions recognized the substrate through flexible conformational changes in response to the substrate size

    Bacterial inducible expression of plant cell wall-binding protein YesO through conflict between Glycine max and saprophytic Bacillus subtilis

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    大豆と納豆菌のせめぎ合いの仕組みを解明 --生きた大豆は納豆菌を嫌い、納豆菌は死んだ大豆が好き--. 京都大学プレスリリース. 2020-11-02.Saprophytic bacteria and plants compete for limited nutrient sources. Bacillus subtilis grows well on steamed soybeans Glycine max to produce the fermented food, natto. Here we focus on bacterial responses in conflict between B. subtilis and G. max. B. subtilis cells maintained high growth rates specifically on non-germinating, dead soybean seeds. On the other hand, viable soybean seeds with germinating capability attenuated the initial growth of B. subtilis. Thus, B. subtilis cells may trigger saprophytic growth in response to the physiological status of G. max. Scanning electron microscope observation indicated that B. subtilis cells on steamed soybeans undergo morphological changes to form apertures, demonstrating cell remodeling during saprophytic growth. Further, transcriptomic analysis of B. subtilis revealed upregulation of the gene cluster, yesOPQR, in colonies growing on steamed soybeans. Recombinant YesO protein, a putative, solute-binding protein for the ATP-binding cassette transporter system, exhibited an affinity for pectin-derived oligosaccharide from plant cell wall. The crystal structure of YesO, in complex with the pectin oligosaccharide, was determined at 1.58 Å resolution. This study expands our knowledge of defensive and offensive strategies in interspecies competition, which may be promising targets for crop protection and fermented food production

    Can intraoperative kinematic analysis predict postoperative kinematics following total knee arthroplasty? A preliminary study

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    The preliminary study analyzed the relationship between intraoperative navigation-based kinematics and postoperative 2-dimensional/3-dimensional (2D/3D) image registration-based kinematics in total knee arthroplasty (TKA). Six knees in 5 patients were analyzed. All TKA procedures were performed using an image-free knee navigation system. Tibial internal rotation was assessed by intraoperative knee kinematics. At 1 year after surgery, tibial internal rotation was evaluated using a 2D/3D image registration technique under loaded and unloaded conditions. The correlation between intraoperative and postoperative data for the tibial internal rotation angle at 10° increments of knee flexion was then assessed. Difference in the knee flexion angle between the intraoperative and postoperative evaluations was adjusted to account for the sagittal cutting angle of the distal femur and proximal tibia. A correlation was found between the intraoperative and postoperative data for loaded knee flexion with this adjustment (Pearson’s r = 0.725, p = 0.012). However, intraoperative kinematics was not significantly correlated with postoperative kinematics in the absence of loading. Larger adequately powered prospective studies are now needed to confirm our preliminary finding that postoperative loaded kinematics can be predicted by intraoperative evaluation

    The Jurassic of the Northern Calcareous Alps and its Global Boundary Stratotype Section and Point (GSSP)

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    This paper summarises the recent progress and current status of research undertaken on the Jurassic strata of the Northern Calcareous Alps. The Jurassic GSSP (Global Boundary Stratotype Section and Point) at the Kuhjoch section of the Northern Calcareous Alps is also explained in detail. The base of the Jurassic strata is defined at this location by the occurrence of the oldest known Jurassic ammonite, Psiloceras spelae tirolicum Hillebrandt & Krystyn. The Upper Triassic to Lower Jurassic successions of the Northern Calcareous Alps were developed along the passive continental margin of the Neotethys Ocean. In Middle Jurassic time, a change in the plate tectonic setting influenced the sedimentary facies, which suggest northwest-verging nappe stacking in association with the partial closure of the Neotethys Ocean. Deep-water radiolarite basins developed in the area in front of the advancing nappes and were the sites of mass flow deposits that produced olistoliths of various sizes. These olistoliths were included in the radiolarite matrices. Therefore, the use of radiolarian fossils as a dating method plays an important role in understanding the formations of the Northern Calcareous Alps.ジュラ系の国際境界模式層序・位置がオーストリア国チロル州のクーヨッホ層序断面に置かれることが2010年に正式に決まった.それはジュラ紀最古のアンモナイトPsiloceras spelae tirolicumが初産出する層準で,ケンドゥルバッハ層の基底から5.8m上位に位置する.筆者らは2012年に行われた国際堆積学会の巡検でクーヨッホ層序断面を訪れたので,その概要を紹介する. ジュラ系の国際模式境界が置かれた北部石灰アルプスでは,近年の研究でオリストリスの基質をなす珪質堆積岩からジュラ紀の放散虫化石が数多く報告され,年代決定に有効なことが示された.本稿では特に研究が進んでいるザルツカンマーグート地方の代表的なジュラ紀層を紹介し,北部石灰アルプスの地質構造発達史を概観する

    Malabaricone C as natural Sphingomyelin Synthase Inhibitor against diet-induced obesity and its lipid metabolism in mice

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    The interaction between natural occurring inhibitors and targeted membrane proteins could be an alternative medicinal strategy for the treatment of metabolic syndrome, notably, obesity. In this study, we identified malabaricones A–C and E (1–4) isolated from the fruits of Myristica cinnamomea King as natural inhibitors for sphingomyelin synthase (SMS), a membrane protein responsible for sphingolipid biosynthesis. Having the most promising inhibition, oral administration of compound 3 exhibited multiple efficacies in reducing weight gain, improving glucose tolerance, and reducing hepatic steatosis in high fat diet-induced obesity mice models. Liver lipid analysis revealed a crucial link between the SMS activities of compound 3 and its lipid metabolism in vitro and in vivo. The nontoxic nature of compound 3 makes it a suitable candidate in search of drugs which can be employed in the treatment and prevention of obesity

    The Posterior Condylar Cartilage Affects Rotational Alignment of the Femoral Component in Varus Knee Osteoarthritis

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    Rotational alignment of the femoral component in total knee arthroplasty (TKA) is important for patellar tracking and ligament balance. Preoperative planning based on radiography might have a potential risk for over-rotation because these X-ray based measurements can not detect asymmetric cartilage wear on posterior condyle. The purpose of this study is to evaluate the effect of the posterior condylar cartilage of varus osteoarthritic knee on rotational alignment of the femoral component in TKA. We established two different condylar twist angles (CTA) from intraoperative multiplanar reconstruction (MPR) images and intraoperative information of navigation system. The CTA measured by a navigation system that includes the cartilage (4.8±2.0°) was smaller than those measured by MPR images, which does not include the cartilage (6.6±2.1°) (p<0.05). The difference between these two angles that corresponds to the remaining posterior condylar cartilage was 1.7±1.2°. This result demonstrated that the posterior condylar cartilage might lead to over-rotational of the femoral component in varus osteoarthritic knee. Therefore, when determining rotational alignment of the femoral component, surgeons should consider the effect of the remaining posterior condylar cartilage to avoid the over-rotation of the femoral component, especially in severe varus knees

    Genetic variants of SLC17A1 are associated with cholesterol homeostasis and hyperhomocysteinaemia in Japanese men

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    Hyperuricaemia is an undisputed and highly predictive biomarker for cardiovascular risk. SLC17A1, expressed in the liver and kidneys, harbours potent candidate single nucleotide polymorphisms that decrease uric acid levels. Therefore, we examined SLC17A1 polymorphisms (rs1165196, rs1179086 and rs3757131), which might suppress cardiovascular risk factors and that are involved in liver functioning, via a large-scale pooled analysis of the Japanese general population in a cross-sectional study. Using data from the Japan Multi-Institutional Collaborative Cohort Study, we identified 1842 participants of both sexes, 35–69-years-old, having the requisite data and analysed their SLC17A1 genotypes. In men, logistic regression analyses revealed that minor alleles in SLC17A1 polymorphisms (rs1165196 and rs3757131) were associated with a low-/high-density lipoprotein cholesterol ratio >2.0 (rs1165196: odds ratio [OR], 0.703; 95% confidence interval [CI], 0.536–0.922; rs3757131: OR, 0.658; 95% CI, 0.500–0.866) and with homocysteine levels of >10.0 nmol/mL (rs1165196: OR, 0.544; 95% CI, 0.374–0.792; rs3757131: OR, 0.509; 95% CI, 0.347–0.746). Therefore, these polymorphisms had dominant negative effects on cholesterol homeostasis and hyperhomocysteinaemia, in men, independent of alcohol consumption, physical activity, or daily energy and nutrition intake. Thus, genetic variants of SLC17A1 are potential biomarkers for altered cholesterol homeostasis and hyperhomocysteinaemia in Japanese men
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