Structure--activity relationships in human interleukin-1{alpha}: identification of key residues for expression of biological activities

To identify the sites important for the different biologicalactivities of human interleukin-l (hIL-1), 56 single-amino acid-substitutedmutants of hIL-l were produced in Escherichia coli using site-directedmutagenesis, and were examined for their biological activitiessuch as mouse lymphocyte activating factor activity (LAF activity),cytostatic activity against human melanoma cells A-375 (A375activity) and prostaglandin E2 (PGE2) inducing activity in humanosteosarcoma cells MG-63 (PEI activity). Two amino acid residues,Asp26 and Asp151, were found to be important for these activities.The replacement of Asp26 by Val caused a decrease in LAF andA375 activities by one or two orders of magnitude and a slightdecrease in A375 activity. The Tyr or Phe substitution for Asp151caused decreases in LAF and A375 activities by one or two ordersof magnitude and complete loss of PEI activity. The change fromAsp151 to Lys or Arg resulted in marked decrease in LAF activityand complete loss of A375 and PEI activities. Since Asp26 andAsp151 are close to each other in the three-dimensional structure,the region involving these amino acids seems to be importantfor the biological activities of hIL-1.     

Involvement of reactive oxygen species generated from melanin synthesis pathway in phytotoxicty of <Emphasis Type="SmallCaps">L</Emphasis>-Dopa

l-DOPA is an active allelochemical that inhibits plant growth. To determine whether the phytotoxicity is due to the reactive oxygen species generated during its oxidation to melanin, oxidative damage, melanin accumulation, and the effect of antioxidants on its phytotoxicity were examined in l-DOPA-tolerant (barnyard grass) and -susceptible (lettuce) plants, and in suspension-cultured carrot cells. l-DOPA suppressed root elongation in lettuce compared to barnyard grass. Levels of melanin and thiobarbituric acid reactive substances (TBARS) increased remarkably in l-DOPA-treated lettuce roots, but not in barnyard grass. l-DOPA also suppressed carrot cell growth to 60% of the control at 1 mM. Melanin content in 1 mM l-DOPA-treated carrot cells increased continuously; however, ascorbic acid and -tocopherol suppressed accumulation. When melanin formation was inhibited by ascorbic acid and -tocopherol, growth of l-DOPA-treated cells was restored. TBARS levels were higher in 1 mM l-DOPA-treated carrot cells than in untreated control cells 2 d after treatment, but not at 4 or 6 d. Ascorbic acid and -tocopherol suppressed the production of lipid peroxide during the initial 2 d. These results suggest that the phytotoxicity of l-DOPA is due to oxidative stress caused by reactive oxygen species from the melanin synthesis pathway.     

Dispersion Behavior of Barium Titanate Nanoparticles Prepared by Using Various Polycarboxylic Dispersants

The effects of the polycarboxylic dispersant structures on the crystallinity and sedimentation behavior of prepared BaTiO₃ nanoparticles were analyzed using four types of dispersants—ethylenediaminetetraacetic acid dipotassium salt (EDTA), trans -aconitic acid (TAA), ammonium acrylate–methyl acrylate co-polymer (PAA50), and sodium polyacrylate (PAA100). In the case of EDTA and TAA, the adsorbed ratio of the dispersants on BaTiO₃ nanoparticles was relatively low, and only slight improvement of sedimentation behavior was observed. On the other hand, in the case of PAA50 and PAA100, the adsorbed ratio was high, and the sedimentation behavior was gratefully improved. Next, in order to analyze the relationships among the additive amount of polycarboxylic dispersants, crystallinity, and sedimentation behavior, various amounts of PAA100 or PAA50 were treated in the synthesis solution. The sedimentation behavior of BaTiO₃ nanoparticles improved with increasing amounts of PAA100 and PAA50 while their crystal phase became amorphous. Adding PAA50 at a molar ratio of COO⁻/Ba²⁺=0.266 resulted in BaTiO₃ nanoparticles with the best dispersion stability in an aqueous media.     

Total structures of colistin minor components

Structural characterization of the colistin (CL) components were carried out using Frit-fast atom bombardment liquid chromatography/mass spectrometry (Frit-FAB LC/MS), tandem mass spectrometry (MS/MS) and the amino acid analysis proposed by MARFEY, and the total structures of 4 minor components including the absolute configuration of the constituent amino acids were proposed. The structures of the minor components were the same as those of the main component colistin A or B except that L-leucine is replaced by L-valine or L-isoleucine.     

N-terminal domain of eotaxin-3 is important for activation of CC chemokine receptor 3

Eotaxin-3 belongs to the CC chemokine family, and specificallyrecognizes CC chemokine receptor (CCR) 3 that is expressed oneosinophils, basophils and helper T type 2 cells. The three-dimensionalstructure of eotaxin-3 determined by nuclear magnetic resonancehas revealed that the N-terminal nine residues preceding thefirst cysteine comprise an unstructured domain, which is alsoobserved in other chemokine molecules. In order to determinethe function of the N-terminal domain of eotaxin-3, we constructedvarious N-terminal-deletion mutants, and then examined theirbinding and chemotactic activities toward eosinophils in vitro.Competitive binding studies showed that the binding affinityof truncated mutant toward CCR3 was almost the same as thatof wild-type eotaxin-3 even though the N-terminal truncationinvolved the first through to the ninth residues. In contrast,the chemotactic activity gradually decreased with extensionof the N-terminal deletion, and when the deletion extended tothe eighth residue, the activity was not detected at all. Thus,the N-terminal nine residues are not critical for binding butthe N-terminal eight residues are essential for activation ofCCR3. The truncated eotaxin-3 proteins lacking the N-terminaleight or nine residues inhibited the chemotactic activity ofchemokines that recognize CCR3. The truncated mutants can possiblybe used for anti-allergic and anti-HIV-1 therapy.     

High prevalence of e antigen among healthy blood donors carrying hepatitis B surface antigen in Japan

Hepatitis B surface antigen (HBsAg) was detected by an immune adherence haemagglutination method in the serum samples of 292 voluntary, apparently healthy blood donors at four regional blood centres in Japan. Their serum samples were concentrated 3-fold and tested for e antigen (e Ag) and antibody to e (anti-e) by immunodiffusion. The e Ag was found in 41 samples (14.0%) and anti-e in 57 (18.6%). When 100 randomly selected serum samples containing HBsAg were tested as they were (unconcentrated), and at 3- and 5-fold concentrations, e Ag was detected in 3, 16 and 27, respectively, and anti-e in 10, 21 and 26. Subtypes of HBsAg were similar in carriers with e Ag and with anti-e. There is a high prevalence of e Ag in healthy individuals in Japan. There are also high rates of vertical transmission of hepatitis B virus from mothers to children, as well as a high incidence in the past of post-transfusion hepatitis. This is further evidence that e antigen is a marker for the infectivity of hepatitis B virus in carriers.     

Vitamin B6 suppresses serine protease inhibitor 3 expression in the colon of rats and in TNF-α-stimulated HT-29 cells

Scope: Previous reports in the areas of animal studies and, recently epidemiology, have linked anti‐tumorigenic and anti‐inflammatory effects to dietary vitamin B6. This study investigated the molecular mechanism of these effects of vitamin B6. Methods and results: DNA microarray analysis was used to obtain information on changes in colon gene expression from vitamin B6 (pyridoxine) repletion in vitamin B6‐deficient rats. Pyridoxine supplementation down‐regulated the inflammatory molecule, serine protease inhibitor clade A member 3 (SPI‐3) mRNA expression in the colon. This study also showed that tumor necrosis factor α (TNF‐α) induced SPI‐3 mRNA expression in HT‐29 human colon cancer cells, and vitamin B6 (pyridoxal hydrochloride) pretreatment of HT‐29 cells inhibited TNF ‐induced mRNA expression of SPI‐3. Vitamin B6 inhibited TNF‐α‐induced NF‐κB activation via suppression of IκBα degradation in HT‐29 cells. HT‐29 cells stably expressing epitope‐tagged ubiquitin were generated and vitamin B6 pretreatment was shown to inhibit ubiquitination of the IkB protein in response to TNF‐α‐i. Conclusion: Vitamin B6 suppressed SPI‐3 expression in the colon of rats and in TNF‐α‐stimulated HT‐29 cells. Further, this study showed a possible role of vitamin B6 in the regulation of protein ubiquitination.     

Removal of lead compounds from polyvinylchloride in electric wires and cables using cation-exchange resin

Recycling treatment of cable insulation resin generated from electric wires and cables was investigated. Conventional insulation PVC contains a lead component, tribase, as a thermal stabilizer and lead removal is necessary to recycle this PVC as insulation resin. This paper describes a solid surface adsorption method using ion exchange resin to remove the fine lead containing particles from PVC dissolved solution. Low lead concentration in the recovered PVC, complying with the requirements of RoHS, was achieved.     

透射式CT与自射线式CT检测核废物桶蒙特卡罗模拟

用蒙特止罗方法对透射式CT（TCT）和自射线式CT（ECT）检测核废物进行模拟实验,用TCT的模拟结果对ECT的模拟结果进行材料吸收系数校正,可以较为准确地确定核废物桶中放射性活度的绝对分布,并可确定放射性核素的种类。     

Phylogenetic diversity of microbial communities associated with the crude-oil, large-insoluble-particle and formation-water components of the reservoir fluid from a non-flooded high-temperature petroleum reservoir

The diversity of microbial communities associated with non-water-flooded high-temperature reservoir of the Niibori oilfield was characterized. Analysis of saturated hydrocarbons revealed that n-alkanes in crude oil from the reservoir were selectively depleted, suggesting that crude oil might be mildly biodegraded in the reservoir. To examine if any specific microorganism(s) preferentially attached to the crude oil or the other components (large insoluble particles and formation water) of the reservoir fluid, 16S rRNA gene clone libraries were constructed from each component of the reservoir fluid. The clones in the archaeal libraries (414 clones in total) represented 16 phylotypes, many of which were closely related to methanogens. The bacterial libraries (700 clones in total) were composed of 49 phylotypes belonging to one of 16 phylum-level groupings, with Firmicutes containing the greatest diversity of the phylotypes. In the crude-oil- and large-insoluble-particle-associated communities, a Methanosaeta-related phylotype dominated the archaeal sequences, whereas hydrogenotrophic methanogens occupied a major portion of sequences in the library of the formation-water-associated community. The crude-oil associated bacterial community showed the largest diversity, containing 35 phylotypes, 16 of which were not detected in the other bacterial communities. Thus, although the populations associated with the reservoir-fluid components largely shared common phylogenetic context, a specific fraction of microbial species preferentially attached to the crude oil and insoluble particles.