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Biosynthesis of the oxygenated diterpene nezukol in the medicinal plant Isodon rubescens is catalyzed by a pair of diterpene synthases
No full textPlants produce an immense diversity of natural products (i.e. secondary or specialized metabolites) that offer a rich source of known and potentially new pharmaceuticals and other desirable bioproducts. The Traditional Chinese Medicinal plant Isodon rubescens (Lamiaceae) contains an array of bioactive labdane-related diterpenoid natural products. Of these, the ent-kauranoid oridonin is the most prominent specialized metabolite that has been extensively studied for its potent antimicrobial and anticancer efficacy. Mining of a previously established transcriptome of I. rubescens leaf tissue identified seven diterpene synthase (diTPSs) candidates. Here we report the functional characterization of four I. rubescens diTPSs. IrTPS5 and IrTPS3 were identified as an ent-copalyl diphosphate (CPP) synthase and a (+)-CPP synthase, respectively. Distinct transcript abundance of IrTPS5 and the predicted ent-CPP synthase IrTPS1 suggested a role of IrTPS5 in specialized ent-kaurene metabolism possibly en route to oridonin. Nicotiana benthamiana co-expression assays demonstrated that IrTPS4 functions sequentially with IrTPS3 to form miltiradiene. In addition, IrTPS2 converted the IrTPS3 product (+)-CPP into the hydroxylated tricyclic diterpene nezukol not previously identified in I. rubescens. Metabolite profiling verified the presence of nezukol in I. rubescens leaf tissue. The proposed IrTPS2-catalyzed reaction mechanism proceeds via the common ionization of the diphosphate group of (+)-CPP, followed by formation of an intermediary pimar-15-en-8-yl+ carbocation and neutralization of the carbocation by water capture at C-8 to yield nezukol, as confirmed by nuclear magnetic resonance (NMR) analysis. Oxygenation activity is rare for the family of class I diTPSs and offers new catalysts for developing metabolic engineering platforms to produce a broader spectrum of bioactive diterpenoid natural products
Correction: Corrigendum: The CUL3-SPOP-DAXX axis is a novel regulator of VEGFR2 expression in vascular endothelial cells
No full textScientific Reports 7: Article number: 42845; published online: 20 February 2017; updated: 22 December 2017. The original version of this Article contained an error in the spelling of the author Yuuki Imai, which was incorrectly given as Yu-ki Imai. This error has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Information.</jats:p
Evaluation of acceptor selectivity of Lactococcus lactis ssp. lactis trehalose 6-phosphate phosphorylase in the reverse phosphorolysis and synthesis of a new sugar phosphate
No full textTrehalose 6-phosphate phosphorylase (TrePP), a member of glycoside hydrolase family 65, catalyzes the reversible phosphorolysis of trehalose 6-phosphate (Tre6P) with inversion of the anomeric configuration to produce beta-D-glucose 1-phosphate (beta-Glc1P) and D-glucose 6-phosphate (Glc6P). TrePP in Lactococcus lactis ssp. lactis (LlTrePP) is, alongside the phosphotransferase system, involved in the metabolism of trehalose. In this study, recombinant LlTrePP was produced and characterized. It showed its highest reverse phosphorolytic activity at pH 4.8 and 40 degrees C, and was stable in the pH range 5.0-8.0 and at up to 30 degrees C. Kinetic analyses indicated that reverse phosphorolysis of Tre6P proceeded through a sequential bi bi mechanism involving the formation of a ternary complex of the enzyme, beta-Glc1P, and Glc6P. Suitable acceptor substrates were Glc6P, and, at a low level, D-mannose 6-phosphate (Man6P). From beta-Glc1P and Man6P, a novel sugar phosphate, alpha-D-Glcp-(1 1)-alpha-D-Manp6P, was synthesized with 51% yield
Minedition
No full textThis is a lovely book I happened to find when I was trying to spend down the little money left on my Eurocheck debit card in the late days of my stay in Mannheim. The book is unusual in opening not from right to left but from down to up; that is, one needs to hold it sideways and lift the cover. The cover picture shows the half-painted jackdaw as he returns after opening his craw and being recognized by the doves whose food he was eating. Why does his fellow jackdaw have various colored feathers protruding from his black body and even one such feather in his beak? The pearl that the rooster finds in CJ is part of a ring. The little goat dancing for the wolf uses a hula-hoop! The expanding frog in OF is about to reach the ceiling of a modernistic garden-house! He is elevated off the floor like a helium-filled balloon. The one illustration for FS includes both the plate for the stork and the vase for the fox. In fact, the wall behind the stork features several plates and the floor behind the fox shows three large vases with steam bubbles emerging from them. The resting hare in TH has a hammock slung across the trail. The dropped meat bubbles through the text, dividing its lines in DS. The grapes break down through the ceiling of the fox's room in FG as clouds blow through the windows. The city mouse is fishing in the soup at the city meal in TMCM! A highway--or a racetrack?--winds among cheese wedges and salt and pepper shakers in this fable's tailpiece. The rack of the stag in the pool reaches out like a tree and even includes a birdhouse! What lovely imaginative work! The book is, as regularly with Neugebauer, beautifully produced.This is a hardbound book (hard cover)Language note: GermanNacherzählt von Renate Raeck
伝統的建造物群保存地区におけるイベント型観光の可能性 －橿原市今井町の事例－
No full textMany important preservation districts of groups of historic buildings have developed as tourist destinations in Japan. But Imai-cho in the City of Kashihara - one of the most famous historical districts in Japan - is situated as residential zone in Kasihara city planning and previous studies said that residents in Imai-cho did not want to develop their district as a normal tourist destination. Therefore, this article aims to examine the possibility of developing an event tourism in the Imai-cho. Events opened on each Saturday and Sunday in November in 2009. Many events, such as concerts, lectures, bar and so forth opened from Saturday afternoon to Sunday afternoon. In these events, some tourists stayed at historical buildings. The author examines the assessments of these events by the questionnaire to tourists and residents in the Imai-cho. There are many tourist attractions such as public open spaces, museums and important cultural properties in the Imai-cho. But souvenir shops and eating and drinking places are not plenty for tourists and there is no main shopping street in the Imai-cho. Most of tourists lived within Kinki region. They usually went to other destinations after they stayed in the Imai-cho during only few hours. They hoped the Imai-cho will develop as historical tourist destination. But some tourists and residents hoped the Imai-cho not to develop as a normal tourist destination. They hoped to develop the event tourism in the Imai-cho in order to preserve life of residents.departmental bulletin pape
Efficient one-pot enzymatic synthesis of trehalose 6-phosphate using GH65 α-glucoside phosphorylases
No full textTrehalose 6-phosphate (Tre6P) is an important intermediate for trehalose biosynthesis. Recent researches have revealed that Tre6P is an endogenous signaling molecule that regulates plant development and stress responses. The necessity of Tre6P in physiological studies is expected to be increasing. To achieve the cost-effective production of Tre6P, a novel approach is required. In this study, we utilized trehalose 6-phosphate phosphorylase (TrePP) from Lactococcus lactis to produce Tre6P. In the reverse phosphorolysis by the TrePP, 91.9 mM Tre6P was produced from 100 mM β-glucose 1-phosphate (β-Glc1P) and 100 mM glucose 6-phosphate (Glc6P). The one-pot reaction of TrePP and maltose phosphorylase (MP) enabled production of 65 mM Tre6P from 100 mM maltose, 100 mM Glc6P, and 20 mM inorganic phosphate. Addition of β-phosphoglucomutase to this reaction produced Glc6P from β-Glc1P and thus reduced requirement of Glc6P as a starting material. Within the range of 20-469 mM inorganic phosphate tested, the 54 mM concentration yielded the highest amount of Tre6P (33 mM). Addition of yeast increased the yield because of its glucose consumption. Finally, from 100 mmol maltose and 60 mmol inorganic phosphate, we successfully achieved production of 37.5 mmol Tre6P in a one-pot reaction (100 mL), and 9.4 g Tre6P dipotassium salt was obtained
Function of Plant DExD/H-Box RNA Helicases Associated with Ribosomal RNA Biogenesis
No full textRibosome biogenesis is a highly complex process that requires several cofactors, including DExD/H-box RNA helicases (RHs). RHs are a family of ATPases that rearrange the secondary structures of RNA and thus remodel ribonucleoprotein complexes. DExD/H-box RHs are found in most organisms and play critical roles in a variety of RNA-involved cellular events. In human and yeast cells, many DExD/H box RHs participate in multiple steps of ribosome biogenesis and regulate cellular proliferation and stress responses. In plants, several DExD/H-box RHs have been demonstrated to be associated with plant development and abiotic stress tolerance through their functions in modulating pre-rRNA processing. In this review, we summarize the pleiotropic roles of DExD/H-box RHs in rRNA biogenesis and other biological functions. We also describe the overall function of the DExD/H-box RH family in ribosome biogenesis based on data from human and yeast
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