Thermodynamic properties of spontaneous magnetization in Chern-Simons QED_3

The spontaneous magnetization in Chern-Simons QED_3 is discussed in a finite temperature system. The thermodynamical potential is analyzed within the weak field approximation and in the fermion massless limit. We find that there is a linear term with respect to the magnetic field with a negative coefficient at any finite temperature. This implies that the spontaneous magnetic field does not vanish even at high temperature. In addition, we examine the photon spectrum in the system. We find that the bare Chern-Simons coefficient is cancelled by the radiative effects. The photons then become topologically massless according to the magnetization, though they are massive by finite temperature effects. Thus the magnetic field is a long-range force without the screening even at high temperature.Comment: 32 pages, Latex, 4 eps figure

Randomised phase II trial of mFOLFOX6 plus bevacizumab versus mFOLFOX6 plus cetuximab as first-line treatment for colorectal liver metastasis (ATOM trial)

BackgroundChemotherapy with biologics followed by liver surgery improves the resection rate and survival of patients with colorectal liver metastasis (CRLM). However, no prospective study has compared the outcomes of chemotherapy with bevacizumab (BEV) versus cetuximab (CET).MethodsThe ATOM study is the first randomised trial comparing BEV and CET for initially unresectable CRLM. Patients were randomly assigned in a 1:1 ratio to receive mFOLFOX6 plus either BEV or CET. The primary endpoint was progression-free survival (PFS).ResultsBetween May 2013 and April 2016, 122 patients were enrolled. Median PFS was 11.5 months (95% CI 9.2–13.3 months) in the BEV group and 14.8 months (95% CI 9.7–17.3 months) in the CET group (hazard ratio 0.803; P = 0.33). Patients with a smaller-number but larger-sized metastases did better in the CET group. In the BEV and CET groups, the response rates were 68.4% and 84.7% and the resection rates were 56.1% and 49.2%, respectively.ConclusionAlthough CET achieved a better response rate than BEV for patients with a small number of large liver metastases, both biologics had similar efficacy regarding liver resection and acceptable safety profiles. To achieve optimal PFS, biologics should be selected in accordance with patient conditions.Trial registrationThis trial is registered at ClinicalTrials.gov (number NCT01836653), and UMIN Clinical Trials Registry (UMIN-CTR number UMIN000010209)

Functional identification of alginate lyase from the brown alga Saccharina japonica

Despite the progress in massive gene analysis of brown algal species, no alginate-degrading enzyme from brown alga has been identified, impeding the understanding of alginate metabolism in brown alga. In the current study, we identified and characterized alginate lyase from Saccharina japonica using a protein-based approach. First, cDNA library was prepared from the S. japonica sporophyte. Expression screening was then performed; the encoding gene was identified and cloned; and the recombinant enzyme was purified and characterized. Alginate lyase production in algal tissues was evaluated by western blotting. The identified alginate lyase, SjAly (359 amino acids, with a predicted N-terminal secretion signal of 27 residues), is encoded by an open reading frame comprising seven exons. Recombinant SjAly exhibited endolytic alginate lyase activity, specifically toward stretches of consecutive β-d-mannuronic acid units. The optimum temperature, pH, and NaCl concentration were 30 °C, pH 8.0, and 100 mM, respectively. SjAly exhibited pronounced activity below 20 °C, the S. japonica growth temperature. SjAly was highly expressed in the blade but not the stipe and rhizoid. The data indicate that S. japonica possesses at least one active alginate lyase. This is the first report of a functional alginate lyase from brown alga, the major natural alginate producer

Enzymatic properties and the primary structure of a β-1,3-glucanase from the digestive fluid of the Pacific abalone Haliotis discus hannai

A β-1,3-glucanase (EC 3.2.1.6) with a molecular mass of 33 kDa was isolated from the digestive fluid of the Pacific abalone Haliotis discus hannai by ammonium sulfate fractionation followed by conventional column chromatography. This enzyme, named HdLam33 in the present study, degraded laminarin and laminarioligosaccharides to laminaribiose and glucose with the optimal temperature and pH at 50℃ and 6.0, respectively. HdLam33 possessed transglycosylation activity, a characteristic property of glucan hydrolases that split glycoside linkage with a retaining manner. By the transglycosylation reaction of HdLam33, the laminaribiose unit in the non-reducing terminus of laminaritriose (donor substrate) was transferred to a free laminaribiose (acceptor substrate) resulting laminaritetraose and glucose. The resulted laminaritetraose was subsequently hydrolyzed by HdLam33 into two moles of glucose and one mole of laminaribiose. The primary structure of HdLam33 was analyzed by the cDNA method. The deduced amino-acid sequence of 329 residues corresponding to the catalytic domain of HdLam33 showed 56-61% amino-acid identity with those of other molluscan β-1,3-glucanases which have been identified as glycoside hydrolase family 16 enzymes

Isolation and characterization of two types of β-1,3-glucanases from the common sea hare Aplysia kurodai

Two types of β-1,3-glucanases, AkLam36 and AkLam33 with the molecular masses of 36 kDa and 33 kDa, respectively, were isolated from the digestive fluid of the common sea hare Aplysia kurodai. AkLam36 was regarded as an endolytic enzyme (EC 3.2.1.6) degrading laminarin and laminarioligosaccharides to laminaritriose, laminaribiose, and glucose, while AkLam33 was regarded as an exolytic enzyme (EC 3.2.1.58) directly producing glucose from polymer laminarin. AkLam36 showed higher activity toward β-1,3-glucans with a few β-1,6-linked glucose branches such as Laminaria digitata laminarin (LLam) than highly branched β-1,3-glucans such as Eisenia bicyclis laminarin (ELam). AkLam33 showed moderate activity toward both ELam and LLam and high activity toward smaller substrates such as laminaritetraose and laminaritriose. Although both enzymes did not degrade laminaribiose as a sole substrate, they were capable of degrading it via transglycosylation reaction with laminaritriose. The N-terminal amino-acid sequences of AkLam36 and AkLam33 indicated that both enzymes belong to the glycosyl hydrolase family 16 like other molluscan β-1,3-glucanases

Ca2+-binding properties and regulatory roles of lobster troponin C sites II and IV

Invertebrate troponin C typically contains Ca2+-specific binding sites, sites II and IV, in the N- and C-terminal domains, respectively. To investigate the roles of these sites for Ca2+-dependent regulation of muscle contraction, we generated lobster troponin C mutants, and analyzed their Ca2+-binding properties and regulatory effects on actomyosin-tropomyosin Mg-ATPase activity. The results suggest that Ca2+ binding to site IV is responsible for regulation at relatively low Ca2+ concentrations, while site II has an essential role in full activation at higher Ca2+ concentrations. (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved

Identification of 2-keto-3-deoxy-D-Gluconate Kinase and 2-keto-3-deoxy-D-Phosphogluconate Aldolase in an Alginate-Assimilating Bacterium, Flavobacterium sp Strain UMI-01

Recently, we identified an alginate-assimilating gene cluster in the genome of Flavobacterium sp. strain UMI-01, a member of Bacteroidetes. Alginate lyase genes and a 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH) reductase gene in the cluster have already been characterized; however, 2-keto-3-deoxy-D-gluconate (KDG) kinase and 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase genes, i.e., flkin and flald, still remained uncharacterized. The amino acid sequences deduced from flkin and flald showed low identities with those of corresponding enzymes of Saccharophagus degradans 2-40T, a member of Proteobacteria (Kim et al., Process Biochem., 2016). This led us to consider that the DEH-assimilating enzymes of Bacteroidetes species are somewhat deviated from those of Proteobacteria species. Thus, in the present study, we first assessed the characteristics in the primary structures of KDG kinase and KDG aldolase of the strain UMI-01, and then investigated the enzymatic properties of recombinant enzymes, recFlKin and recFlAld, expressed by an Escherichia coli expression system. Multiple-sequence alignment among KDG kinases and KDG aldolases from several Proteobacteria and Bacteroidetes species indicated that the strain UMI-01 enzymes showed considerably low sequence identities (15%-25%) with the Proteobacteria enzymes, while they showed relatively high identities (47%-68%) with the Bacteroidetes enzymes. Phylogenetic analyses for these enzymes indicated the distant relationship between the Proteobacteria enzymes and the Bacteroidetes enzymes, i.e., they formed distinct clusters in the phylogenetic tree. recFlKin and recFlAld produced with the genes flkin and flald, respectively, were confirmed to show KDG kinase and KDPG aldolase activities. Namely, recFlKin produced 1.7 mM KDPG in a reaction mixture containing 2.5 mM KDG and 2.5 mM ATP in a 90-min reaction, while recFlAld produced 1.2 mM pyruvate in the reaction mixture containing 5 mM KDPG at the equilibrium state. An in vitro alginate-metabolizing system constructed from recFlKin, recFlAld, and previously reported alginate lyases and DEH reductase of the strain UMI-01 could convert alginate to pyruvate and glyceraldehyde-3-phosphate with an efficiency of 38%

Characterization of an α-glucosidase, HdAgl, from the digestive fluid of Haliotis discus hannai

Previously, we isolated two alpha-amylase isozymes, HdAmy58 and HdAmy82, from the digestive fluid of the Pacific abalone Haliotis discus hannai (Kumagai et al., 2013, Comp. Biochem. Physiol., B 164, 80-88). These enzymes degraded starch producing maltooligosaccharides but not glucose. However, the digestive fluid itself could produce glucose from starch, indicating that the digestive fluid contains alpha-glucosidase-like enzymes together with the alpha-amylases. Thus, in the present study, we isolated this alpha-glucosidase-like enzyme from the digestive fluid and characterized it to some extent. Isolation of this enzyme was carried out by ammonium sulfate fractionation followed by conventional column chromatographies and FPLC. The purified enzyme showed an apparent molecular mass of 97 kDa on SDS-PAGE, and optimal temperature and pH of 45 degrees C and 3.8-5.5, respectively. This enzyme could degrade various sizes of maltooligosaccharides into glucose and released glucose from starch producing no appreciable intermediate oligosaccharides. We concluded that this enzyme is an alpha-glucosidase (EC 3.2.1.20) exolitically acting on polymer substrate and named HdAgl. HdAgl efficiently degraded maltose but hardly degraded p-nitrophenyl alpha - D-glucopyranoside (alpha-pNPG) and isomaltose. This enzyme was regarded as a maltase-like alpha-glucosidase that preferably degrades maltose but scarcely aryl glucosides. When starch was used as a substrate, HdAgl converted approximately 40% (w/w) of the starch to glucose. If an abalone alpha-amlylase HdAmy58 was added to the reaction mixture, the glucose yield increased to 60% (w/w). These results suggested that both HdAgl and HdAmy58 play important roles for the production of glucose from dietary starch in the digestive fluid. The amino-acid sequence of 887 residues for HdAgl was deduced by the cDNA method. This sequence showed 41-46% amino-acid identities to those of mammalian and avian alpha-glucosidases belonging to glycoside-hydrolase-family31. (C) 2013 Elsevier Inc. All rights reserved

Characterization of a GHF45 cellulase, AkEG21, from the common sea hare Aplysia kurodai.

ThecommonseahareAplysiakurodaiisknowntobeagoodsourcefortheenzymesdegradingseaweedpolysaccharides.Recentlyfourcellulases,i.e.,95,66,45,and21kDaenzymes,wereisolatedfromA.kurodai(Tsujietal.,2013).Theformerthreecellulaseswereregardedasglycosyl-hydrolase-family9(GHF9)enzymes,whilethe21kDacellulasewassuggestedtobeaGHF45enzyme.The21kDacellulasewassignificantlyheatstable,andappearedtobeadvantageousinperformingheterogeneousexpressionandprotein-engineeringstudy.Inthepresentstudy,wedeterminedsomeenzymaticpropertiesofthe21kDacellulaseandcloneditscDNAtoprovidethebasisfortheproteinengineeringstudyofthiscellulase.Thepurified21kDaenzyme,termedAkEG21inthepresentstudy,hydrolyzedcarboxymethylcellulosewithanoptimalpHandtemperatureat4.5and40◦C,respectively.AkEG21wasconsiderablyheat-stable,i.e.,itwasnotinactivatedbytheincubationat55◦Cfor30min.AkEG21degradedphosphoric-acid-swollencelluloseproducingcellotrioseandcellobioseasmajorendproductsbuthardlydegradedoligosaccharidessmallerthantetrasaccharide.ThisindicatedthatAkEG21isanendolyticβ-1,4-glucanase(EC3.2.1.4).AcDNAof1013bpencodingAkEG21wasamplifiedbyPCRandtheamino-acidsequenceof197residueswasdeduced.ThesequencecomprisedtheinitiationMet,theputativesignalpeptideof16residuesforsecretionandthecatalyticdomainof180residues,whichlinedfromtheN-terminusinthisorder.Thesequenceofthecatalyticdomainshowed47–62%amino-acididentitiestothoseofGHF45cellulasesreportedinothermollusks.BoththecatalyticresiduesandtheN-glycosylationresiduesknowninotherGHF45cellulaseswereconservedinAkEG21.Phylogeneticanalysisfortheamino-acidsequencessuggestedthecloserelationbetweenAkEG21andfungalGHF45cellulases