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Showing papers by "Academia Sinica published in 2002"


Journal ArticleDOI
TL;DR: The use of magnetic resonance diffusion tensor imaging to quantify the effect of dysmyelination on water directional diffusivities in brains of shiverer mice in vivo suggests that changes in lambda(perpendicular) and lambda(parallel) may potentially be used to differentiate myelin loss versus axonal injury.

2,470 citations


Journal ArticleDOI
TL;DR: The results identify previously unsuspected features of mRNA decay at a global level and also indicate that generalizations about decay derived from the study of individual gene transcripts may have limited applicability.
Abstract: Much of the information available about factors that affect mRNA decay in Escherichia coli, and by inference in other bacteria, has been gleaned from study of less than 25 of the ≈4,300 predicted E. coli messages. To investigate these factors more broadly, we examined the half-lives and steady-state abundance of known and predicted E. coli mRNAs at single-gene resolution by using two-color fluorescent DNA microarrays. An rRNA-based strategy for normalization of microarray data was developed to permit quantitation of mRNA decay after transcriptional arrest by rifampicin. We found that globally, mRNA half-lives were similar in nutrient-rich media and defined media in which the generation time was approximately tripled. A wide range of stabilities was observed for individual mRNAs of E. coli, although ≈80% of all mRNAs had half-lives between 3 and 8 min. Genes having biologically related metabolic functions were commonly observed to have similar stabilities. Whereas the half-lives of a limited number of mRNAs correlated positively with their abundance, we found that overall, increased mRNA stability is not predictive of increased abundance. Neither the density of putative sites of cleavage by RNase E, which is believed to initiate mRNA decay in E. coli, nor the free energy of folding of 5′ or 3′ untranslated region sequences was predictive of mRNA half-life. Our results identify previously unsuspected features of mRNA decay at a global level and also indicate that generalizations about decay derived from the study of individual gene transcripts may have limited applicability.

881 citations


Journal ArticleDOI
TL;DR: In this article, a class of one-step models for stochastic frontier models with one-sided inefficiency was proposed, where the scale of the model depends on some variables (firm characteristics) and can be estimated in a single step by maximum likelihood.
Abstract: Consider a stochastic frontier model with one-sided inefficiency u, and suppose that the scale of u depends on some variables (firm characteristics) z. A “one-step” model specifies both the stochastic frontier and the way in which u depends on z, and can be estimated in a single step, for example by maximum likelihood. This is in contrast to a “two-step” procedure, where the first step is to estimate a standard stochastic frontier model, and the second step is to estimate the relationship between (estimated) u and z. In this paper we propose a class of one-step models based on the “scaling property” that u equals a function of z times a one-sided error u * whose distribution does not depend on z. We explain theoretically why two-step procedures are biased, and we present Monte Carlo evidence showing that the bias can be very severe. This evidence argues strongly for one-step models whenever one is interested in the effects of firm characteristics on efficiency levels.

824 citations


Journal ArticleDOI
TL;DR: The molecular cloning of GLUCOSE INSENSITIVE1 (GIN1) and ABSCISIC ACID DEFICIENT2 (ABA2) which encodes a unique Arabidopsis short-chain dehydrogenase/reductase (SDR1) that functions as a molecular link between nutrient signaling and plant hormone biosynthesis.
Abstract: Glc has hormone-like functions and controls many vital processes through mostly unknown mechanisms in plants. We report here on the molecular cloning of GLUCOSE INSENSITIVE1 (GIN1) and ABSCISIC ACID DEFICIENT2 (ABA2) which encodes a unique Arabidopsis short-chain dehydrogenase/reductase (SDR1) that functions as a molecular link between nutrient signaling and plant hormone biosynthesis. SDR1 is related to SDR superfamily members involved in retinoid and steroid hormone biosynthesis in mammals and sex determination in maize. Glc antagonizes ethylene signaling by activating ABA2/GIN1 and other abscisic acid (ABA) biosynthesis and signaling genes, which requires Glc and ABA synergistically. Analyses of aba2/gin1 null mutants define dual functions of endogenous ABA in inhibiting the postgermination developmental switch modulated by distinct Glc and osmotic signals and in promoting organ and body size and fertility in the absence of severe stress. SDR1 is sufficient for the multistep conversion of plastid- and carotenoid-derived xanthoxin to abscisic aldehyde in the cytosol. The surprisingly restricted spatial and temporal expression of SDR1 suggests the dynamic mobilization of ABA precursors and/or ABA.

810 citations


Journal ArticleDOI
TL;DR: The results suggest that current environmental levels of TBT and other metals are associated with a significant potential threat to human health for fishermen resident in coastal areas of Taiwan.

445 citations


Journal ArticleDOI
TL;DR: Higher requirement for carbohydrates by AM fungi induces higher soluble sugar accumulation in host root tissues, which is independent of improvement in plant P status and enhances resistance to salt-induced osmotic stress in the mycorrhizal plant.
Abstract: The effect of colonization with the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe on the growth and physiology of NaCl-stressed maize plants (Zea mays L. cv. Yedan 13) was examined in the greenhouse. Maize plants were grown in sand with 0 or 100 mM NaCl and at two phosphorus (P) (0.05 and 0.1 mM) levels for 34 days, following 34 days of non-saline pre-treatment. Mycorrhizal plants maintained higher root and shoot dry weights. Concentrations of chlorophyll, P and soluble sugars were higher than in non-mycorrhizal plants under given NaCl and P levels. Sodium concentration in roots or shoots was similar in mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants had higher electrolyte concentrations in roots and lower electrolyte leakage from roots than non-mycorrhizal plants under given NaCl and P levels. Although plants in the low P plus AM fungus treatment and those with high P minus AM fungus had similar P concentrations, the mycorrhizal plants still had higher dry weights, soluble sugars and electrolyte concentrations in roots. Similar relationships were observed regardless of the presence or absence of salt stress. Higher soluble sugars and electrolyte concentrations in mycorrhizal plants suggested a higher osmoregulating capacity of these plants. Alleviation of salt stress of a host plant by AM colonization appears not to be a specific effect. Furthermore, higher requirement for carbohydrates by AM fungi induces higher soluble sugar accumulation in host root tissues, which is independent of improvement in plant P status and enhances resistance to salt-induced osmotic stress in the mycorrhizal plant.

434 citations


Journal ArticleDOI
TL;DR: Results from the current study suggest that heterologous CBF1expression in transgenic tomato plants may induce several oxidative-stress responsive genes to protect from chilling stress.
Abstract: In an attempt to improve stress tolerance of tomato (Lycopersicon esculentum) plants, an expression vector containing an Arabidopsis C-repeat/dehydration responsive element binding factor 1 (CBF1) cDNA driven by a cauliflower mosaic virus 35S promoter was transferred into tomato plants. Transgenic expression of CBF1 was proved by northern- and western-blot analyses. The degree of chilling tolerance of transgenic T1 and T2 plants was found to be significantly greater than that of wild-type tomato plants as measured by survival rate, chlorophyll fluorescence value, and radical elongation. The transgenic tomato plants exhibited patterns of growth retardation; however, they resumed normal growth after GA3 (gibberellic acid) treatment. More importantly, GA3-treated transgenic plants still exhibited a greater degree of chilling tolerance compared with wild-type plants. Subtractive hybridization was performed to isolate the responsive genes of heterologous Arabidopsis CBF1 in transgenic tomato plants. CATALASE1 (CAT1) was obtained and showed activation in transgenic tomato plants. The CAT1 gene and catalase activity were also highly induced in the transgenic tomato plants. The level of H2O2 in the transgenic plants was lower than that in the wild-type plants under either normal or cold conditions. The transgenic plants also exhibited considerable tolerance against oxidative damage induced by methyl viologen. Results from the current study suggest that heterologous CBF1 expression in transgenic tomato plants may induce several oxidative-stress responsive genes to protect from chilling stress.

433 citations


Journal ArticleDOI
M. Aguilar, J. Alcaraz, Behcet Alpat1, G. Ambrosi2  +223 moreInstitutions (24)
TL;DR: The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 (June 1998) in a 51.7° orbit at altitudes between 320 and 390 km as discussed by the authors.

423 citations


Journal ArticleDOI
TL;DR: Results indicated that the heterologous Arabidopsis CBF1 can confer water deficit resistance in transgenic tomato plants.
Abstract: A DNA cassette containing an Arabidopsis C repeat/dehydration-responsive element binding factor 1 (CBF1) cDNA and a nos terminator, driven by a cauliflower mosaic virus 35S promoter, was transformed into the tomato (Lycopersicon esculentum) genome. These transgenic tomato plants were more resistant to water deficit stress than the wild-type plants. The transgenic plants exhibited growth retardation by showing dwarf phenotype, and the fruit and seed numbers and fresh weight of the transgenic tomato plants were apparently less than those of the wild-type plants. Exogenous gibberellic acid treatment reversed the growth retardation and enhanced growth of transgenic tomato plants, but did not affect the level of water deficit resistance. The stomata of the transgenic CBF1 tomato plants closed more rapidly than the wild type after water deficit treatment with or without gibberellic acid pretreatment. The transgenic tomato plants contained higher levels of Pro than those of the wild-type plants under normal or water deficit conditions. Subtractive hybridization was used to isolate the responsive genes to heterologous CBF1 in transgenic tomato plants and the CAT1 (CATALASE1) was characterized. Catalase activity increased, and hydrogen peroxide concentration decreased in transgenic tomato plants compared with the wild-type plants with or without water deficit stress. These results indicated that the heterologous Arabidopsis CBF1 can confer water deficit resistance in transgenic tomato plants.

419 citations


Journal ArticleDOI
TL;DR: The structures of Ras farnesyltransferase and Rab geranylgeranyltransferase are used to elucidate the reaction mechanism of this group of enzymes, and the mechanism that controls product chain length and the reaction kinetics of IPP condensation in the cis-type and trans-type enzymes are focused on.
Abstract: In this review, we summarize recent progress in studying three main classes of prenyltransferases: (a) isoprenyl pyrophosphate synthases (IPPSs), which catalyze chain elongation of allylic pyrophosphate substrates via consecutive condensation reactions with isopentenyl pyrophosphate (IPP) to generate linear polymers with defined chain lengths; (b) protein prenyltransferases, which catalyze the transfer of an isoprenyl pyrophosphate (e.g. farnesyl pyrophosphate) to a protein or a peptide; (c) prenyltransferases, which catalyze the cyclization of isoprenyl pyrophosphates. The prenyltransferase products are widely distributed in nature and serve a variety of important biological functions. The catalytic mechanism deduced from the 3D structure and other biochemical studies of these prenyltransferases as well as how the protein functions are related to their reaction mechanism and structure are discussed. In the IPPS reaction, we focus on the mechanism that controls product chain length and the reaction kinetics of IPP condensation in the cis-type and trans-type enzymes. For protein prenyltransferases, the structures of Ras farnesyltransferase and Rab geranylgeranyltransferase are used to elucidate the reaction mechanism of this group of enzymes. For the enzymes involved in cyclic terpene biosynthesis, the structures and mechanisms of squalene cyclase, 5-epi-aristolochene synthase, pentalenene synthase, and trichodiene synthase are summarized.

400 citations


Journal ArticleDOI
TL;DR: The physical chemistry of solution silicate species and surfactants in the synthesis of mesoporous silicas is reviewed and controls in surfactant packing and liquid crystalline phase transformation can lead to various tailored synthesis strategies.
Abstract: Micelle-templated mesoporous silica materials are rapidly becoming important in many fields of chemistry for hosting reactants or catalysts in confined space. Fine control of the pore size, wall structure, surface functionalization, defects, and morphology is needed for fine-tuning the pores as nanoreactors. We review the physical chemistry of solution silicate species and surfactants in the synthesis of mesoporous silicas. Controls in surfactant packing and liquid crystalline phase transformation can lead to various tailored synthesis strategies. Postsynthesis treatments further make more stable mesoporous materials.

Proceedings ArticleDOI
23 Jul 2002
TL;DR: By adopting InfoDiscoverer as the preprocessor of information retrieval and extraction applications, the retrieval and extracting precision will be increased, and the indexing size and extracting complexity will also be reduced.
Abstract: In this paper, we propose a new approach to discover informative contents from a set of tabular documents (or Web pages) of a Web site. Our system, InfoDiscoverer, first partitions a page into several content blocks according to HTML tag in a Web page. Based on the occurrence of the features (terms) in the set of pages, it calculates entropy value of each feature. According to the entropy value of each feature in a content block, the entropy value of the block is defined. By analyzing the information measure, we propose a method to dynamically select the entropy-threshold that partitions blocks into either informative or redundant. Informative content blocks are distinguished parts of the page, whereas redundant content blocks are common parts. Based on the answer set generated from 13 manually tagged news Web sites with a total of 26,518 Web pages, experiments show that both recall and precision rates are greater than 0.956. That is, using the approach, informative blocks (news articles) of these sites can be automatically separated from semantically redundant contents such as advertisements, banners, navigation panels, news categories, etc. By adopting InfoDiscoverer as the preprocessor of information retrieval and extraction applications, the retrieval and extracting precision will be increased, and the indexing size and extracting complexity will also be reduced.

Journal ArticleDOI
03 May 2002-Science
TL;DR: Archaefructaceae is proposed as a new basal angiosperm family of herbaceous aquatic plants and is a sister clade to all angiosperms when their characters are included in a combined three-gene molecular and morphological analysis.
Abstract: Archaefructaceae is proposed as a new basal angiosperm family of herbaceous aquatic plants. This family consists of the fossils Archaefructus liaoningensis and A. sinensis sp. nov. Complete plants from roots to fertile shoots are known. Their age is a minimum of 124.6 million years from the Yixian Formation, Liaoning, China. They are a sister clade to all angiosperms when their characters are included in a combined three-gene molecular and morphological analysis. Their reproductive axes lack petals and sepals and bear stamens in pairs below conduplicate carpels.

Journal ArticleDOI
TL;DR: More than 100 macrofossil species have been described from Miaohe shales, but in an examination of published and new materials, they recognize only about twenty distinct taxa, including Aggregatosphaera miaoheensis new gen. and sp. minor as mentioned in this paper.
Abstract: Carbonaceous compression fossils in shales of the uppermost Doushantuo Formation (ca. 555–590 Ma) at Miaohe in the Yangtze Gorges area provide a rare Burgess-Shale-type taphonomic window on terminal Proterozoic biology. More than 100 macrofossil species have been described from Miaohe shales, but in an examination of published and new materials, we recognize only about twenty distinct taxa, including Aggregatosphaera miaoheensis new gen. and sp. Most of these fossils can be interpreted unambiguously as colonial prokaryotes or multicellular algae. Phylogenetically derived coenocytic green algae appear to be present, as do regularly bifurcating thalli comparable to red and brown algae. At least five species have been interpreted as metazoans by previous workers. Of these, Protoconites minor and Calyptrina striata most closely resemble animal remains; either or both could be the organic sheaths of cnidarian scyphopolyps, although an algal origin cannot be ruled out for P. minor. Despite exceptional ...

Journal ArticleDOI
TL;DR: Results imply that the length polymorphism in the HO-1 gene promoter modulate the transcription of the gene in vascular cells, suggesting type 2 diabetics carrying longer (GT)n repeats might have higher oxidative stress and increased susceptibility to the development of CAD.
Abstract: Heme oxygenase is a rate-limiting enzyme in heme degradation, leading to the generation of free iron, biliverdin, and carbon monoxide. Induction of heme oxygenase-1 is implicated in the antioxidant defense mechanism and can modulate vascular function. To test the association of microsatellite polymorphism in the promoter region of human HO-1 gene with the risk of coronary artery disease (CAD) in type 2 diabetic patients, we examined the allele frequencies of (GT) (n) repeats in HO-1 gene in 474 patients with CAD and in 322 controls. A transient-transfection assay with HO-1 promoter/luciferase fusion constructs carrying various lengths of (GT) (n) repeats was performed to explore the regulatory effect of (GT) (n) repeats on HO-1 gene expression in cultured rat aortic smooth muscle cells. Serum thiobarbituric acid-reactive substances (TBARs), a measure of lipid peroxidation, was significantly higher in subjects carrying the L/L genotype (> or =32 repeats). Among type 2 diabetic subjects, the frequencies of the L alleles and proportion of genotypes with L alleles were significantly higher in those with CAD than in those without CAD. The adjusted odds ratio for CAD in type 2 diabetic patients with L alleles was 4.7 (95% confidence interval, 1.9-12.0, P=0.001). Transfection experiments in aortic smooth muscle cells revealed that HO-1 promoter/luciferase fusion constructs containing longer (GT) (n) repeats exhibited lower transcriptional activity. These results imply that the length polymorphism in the HO-1 gene promoter modulate the transcription of the gene in vascular cells. Type 2 diabetics carrying longer (GT) (n) repeats might have higher oxidative stress and increased susceptibility to the development of CAD.

Journal ArticleDOI
TL;DR: It is demonstrated that as evidenced by certain chaperone inductions, Jev infection triggers the UPR in fibroblast BHK-21 cells and in neuronal N18 and NT-2 cells, in which JEV results in apoptotic cell death, suggesting that virus-induced ER stress may participate, via p38-dependent and CHOP-mediated pathways, in the apoptotic process triggered by JEV infection.
Abstract: The malfunctioning of the endoplasmic reticulum (ER) of cells in hosts ranging from yeast to mammals can trigger an unfolded protein response (UPR). Such malfunctioning can result from a variety of ER stresses, including the inhibition of protein glycosylation and calcium imbalance. To cope with ER stresses, cells may rely on the UPR to send a signal(s) from the ER to the nucleus to stimulate appropriate cellular responses, including induction of chaperone expression. During Japanese encephalitis virus (JEV) infection, the lumen of the ER rapidly accumulates substantial amounts of viral proteins for virus progeny production. In the present study, we demonstrate that as evidenced by certain chaperone inductions, JEV infection triggers the UPR in fibroblast BHK-21 cells and in neuronal N18 and NT-2 cells, in which JEV results in apoptotic cell death. By contrast, no UPR was observed in apoptosis-resistant K562 cells infected by JEV. JEV infection also activates expression of CHOP/GADD153, a distinctive transcription factor often induced by the UPR, and appears to trigger activation of p38 mitogen-activated protein kinase, a posttranslational activator of CHOP. Ectopic enforcement of CHOP expression enhanced JEV-induced apoptosis, whereas treatment with a p38-specific inhibitor, SB203580, partially blocked JEV-induced apoptosis. Interestingly, bcl-2 overexpression and treatment with a pancaspase inhibitor, z-VAD-fmk, inhibited CHOP induction and diminished JEV-induced apoptosis, suggesting that Bcl-2 and caspases could be the upstream regulators of CHOP. Our results thus suggest that virus-induced ER stress may participate, via p38-dependent and CHOP-mediated pathways, in the apoptotic process triggered by JEV infection.

Journal ArticleDOI
TL;DR: A culture device is used to sieve out a homogeneous population of cells (termed size‐sieved [SS] cells) from bone marrow aspirates that had the capacity for self‐renewal and the multilineage potential to form bone, fat, and cartilage, and satisfy the characteristics of MSCs.
Abstract: Bone marrow mesenchymal stem cells (MSCs) have the capacity for renewal and the potential to differentiate into multiple lineages of mesenchymal tissues. In the laboratory, MSCs have the tendency to adhere to culture dish plastic and are characterized by fibroblastic morphology, but possess no specific markers to select them. To isolate and purify MSCs from bone marrow, we use a culture device-a plastic culture dish comprising a plate with 3-microm pores-to sieve out a homogeneous population of cells (termed size-sieved [SS] cells) from bone marrow aspirates. SS cells that adhered to the upper porous plate surface were a relatively homogeneous population as indicated by morphology and other criteria, such as surface markers. They had the capacity for self-renewal and the multilineage potential to form bone, fat, and cartilage, and satisfy the characteristics of MSCs. In addition, if all the cells from each passage had been plated and cultured in our defined conditions, over 10(14) SS cells would have been obtained from each 10-ml aspirate in 15 additional weeks of culture. This technically simple method leads to an efficient isolation and purification of cells with the characteristics of MSCs.

Journal ArticleDOI
TL;DR: It is shown that jef (sox9a) is essential for both morphogenesis of condensations and overt cartilage differentiation and in morpholino-injected animals, the percent of splicing inhibition decreased from 80% at 28 hours post fertilization to 45% by 4 days.
Abstract: The molecular genetic mechanisms of cartilage construction are incompletely understood. Zebrafish embryos homozygous for jellyfish (jef) mutations show craniofacial defects and lack cartilage elements of the neurocranium, pharyngeal arches, and pectoral girdle similar to humans with campomelic dysplasia. We show that two alleles of jef contain mutations in sox9a, one of two zebrafish orthologs of the human transcription factor SOX9. A mutation induced by ethyl nitrosourea changed a conserved nucleotide at a splice junction and severely reduced splicing of sox9a transcript. A retrovirus insertion into sox9a disrupted its DNA-binding domain. Inhibiting splicing of the sox9a transcript in wild-type embryos with splice site-directed morpholino antisense oligonucleotides produced a phenotype like jef mutant larvae, and caused sox9a transcript to accumulate in the nucleus; this accumulation can serve as an assay for the efficacy of a morpholino independent of phenotype. RNase-protection assays showed that in morpholino-injected animals, the percent of splicing inhibition decreased from 80% at 28 hours post fertilization to 45% by 4 days. Homozygous mutant embryos had greatly reduced quantities of col2a1 message, the major collagen of cartilage. Analysis of dlx2 expression showed that neural crest specification and migration was normal in jef (sox9a) embryos. Confocal images of living embryos stained with BODIPY-ceramide revealed at single-cell resolution the formation of precartilage condensations in mutant embryos. Besides the lack of overt cartilage differentiation, pharyngeal arch condensations in jef (sox9a) mutants lacked three specific morphogenetic behaviors: the stacking of chondrocytes into orderly arrays, the individuation of pharyngeal cartilage organs and the proper shaping of individual cartilages. Despite the severe reduction of cartilages, analysis of titin expression showed normal muscle patterning in jef (sox9a) mutants. Likewise, calcein labeling revealed that early bone formation was largely unaffected in jef (sox9a) mutants. These studies show that jef (sox9a) is essential for both morphogenesis of condensations and overt cartilage differentiation.

Journal ArticleDOI
Sanyi Tang1, Lansun Chen1
TL;DR: Using the discrete dynamical system determined by the stroboscopic map, an exact periodic solution of systems which are with Ricker functions or Beverton-Holt functions are obtained, and the threshold conditions for their stability are obtained.
Abstract: In most models of population dynamics, increases in population due to birth are assumed to be time-independent, but many species reproduce only during a single period of the year. We propose a single-species model with stage structure for the dynamics in a wild animal population for which births occur in a single pulse once per time period. Using the discrete dynamical system determined by the stroboscopic map, we obtain an exact periodic solution of systems which are with Ricker functions or Beverton-Holt functions, and obtain the threshold conditions for their stability. Above this threshold, there is a characteristic sequence of bifurcations, leading to chaotic dynamics, which implies that the dynamical behaviors of the single species model with birth pulses are very complex, including small-amplitude annual oscillations, large-amplitude multi-annual cycles, and chaos. This suggests that birth pulse, in effect, provides a natural period or cyclicity that allows for a period-doubling route to chaos.

Journal ArticleDOI
TL;DR: This work demonstrates that carbohydrate attached nanoparticles can be used as an efficient affinity label and a multi-ligand carrier in a biological system.
Abstract: The synthesis, characterization and biological application of mannose encapsulated gold nanoparticles (m-AuNP) are reported. m-AuNP is well dispersed and very stable without aggregation in the media of broad ion strength and pH ranges. The selective binding of m-AuNP to the mannose adhesin FimH of bacterial type 1 pili is demonstrated using transmission electron microscopy. The competition assay with free mannose suggests that m-AuNP binds FimH better than free mannose does. This work demonstrates that carbohydrate attached nanoparticles can be used as an efficient affinity label and a multi-ligand carrier in a biological system.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the influence of terrigenous sediments from the Yangtze River on the spatial variations of heavy metals and organic carbon on the East China Sea continental shelf.

Journal ArticleDOI
TL;DR: The KLOE calorimeter as mentioned in this paper is a fine lead-scintillating fiber sampling calorometer with an energy resolution of 5.4% and a time resolution of 56 ps/E (GeV).
Abstract: The KLOE calorimeter is a fine lead-scintillating fiber sampling calorimeter. We describe in the following the calibration procedures and the calorimeter performances obtained after 3 years of data taking. We get an energy resolution for electromagnetic showers of 5.4%/ E (GeV) and a time resolution of 56 ps/ E (GeV) . We also present a measurement of efficiency for low-energy photons.

Journal ArticleDOI
TL;DR: GCMa was able to regulatesyncytin gene expression via two GCMa-binding sites upstream of the 5′-long terminal repeat of thesyncytin-harboring HERV-W family member in BeWo and JEG3 cells but not in HeLa cells, which may help to explain the mechanism underlying the cell fusion event specific for syncytiotrophoblast formation.

Journal ArticleDOI
TL;DR: The present study demonstrates that differential DNA binding affinity, promoter transactivation ability, dimerization, and interactions with other protein factors determine the biological function of OsMYBSs.
Abstract: The expression of α-amylase genes in cereals is induced by both gibberellin (GA) and sugar starvation. All α-amylase genes isolated from cereals contain a TATCCA element or its variants at positions ∼90 to 150 bp upstream of the transcription start sites. The TATCCA element was shown previously to be an important component of the GA response complex and the sugar response complex of α-amylase gene promoters. In the present study, three cDNA clones encoding novel MYB proteins with single DNA binding domains were isolated from a rice suspension cell cDNA library and designated OsMYBS1, OsMYBS2, and OsMYBS3. Gel mobility shift experiments with OsMYBSs showed that they bind specifically to the TATCCA element in vitro. Yeast one-hybrid experiments demonstrated that OsMYBS1 and OsMYBS2 bind to the TATCCA element and transactivate a promoter containing the TATCCA element in vivo. Transient expression assays with barley half-seeds showed that OsMYBS1 and OsMYBS2 transactivate a promoter containing the TATCCA element when sugar is provided, whereas OsMYBS3 represses transcription of the same promoter under sugar starvation. Transient expression assays also showed that these three OsMYBSs cooperate with a GA-regulated transcription factor, HvMYBGa, in the transactivation of a low-pI barley α-amylase gene promoter in the absence of GA. Two-hybrid experiments with barley half-seeds showed that OsMYBS1 is able to form a homodimer. The present study demonstrates that differential DNA binding affinity, promoter transactivation ability, dimerization, and interactions with other protein factors determine the biological function of OsMYBSs. This study also suggests that common transcription factors are involved in the sugar and hormonal regulation of α-amylase gene expression in cereals.

Journal ArticleDOI
TL;DR: Further studies on the activities of this glycoprotein fraction indicate that a fucose containing polysaccharide fraction is responsible for stimulating the expression of cytokines, especially IL-1, IL-2 and INF-gamma.

Journal ArticleDOI
K. Adcox1, S. S. Adler2, N. N. Ajitanand3, Y. Akiba  +319 moreInstitutions (36)
TL;DR: In this article, the PHENIX experiment at RHIC was used to measure the transverse momentum spectra at mid-rapidity in collision centrality, and the average transverse momenta increase with the number of participating nucleons in a similar way for all particle species.
Abstract: Identified ${\ensuremath{\pi}}^{+/\ensuremath{-}}$, ${K}^{+/\ensuremath{-}}$, $p$, and $\overline{p}$ transverse momentum spectra at midrapidity in $\sqrt{{s}_{\mathrm{NN}}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}130\phantom{\rule{0ex}{0ex}}\mathrm{GeV}\phantom{\rule{0ex}{0ex}}\mathrm{Au}+\mathrm{Au}$ collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleons in a similar way for all particle species. Within errors, all midrapidity particle yields per participant are found to be increasing with the number of participating nucleons. There is an indication that ${K}^{+/\ensuremath{-}}$, $p$, and $\overline{p}$ yields per participant increase faster than the ${\ensuremath{\pi}}^{+/\ensuremath{-}}$ yields. In central collisions at high transverse momenta $({p}_{T}\ensuremath{\gtrsim}2\mathrm{GeV}/c)$, $\overline{p}$ and $p$ yields are comparable to the ${\ensuremath{\pi}}^{+/\ensuremath{-}}$ yields.

Journal ArticleDOI
TL;DR: In this paper, the influence of melt on the creep behavior of olivine-basalt aggregates under hydrous conditions has been investigated by performing a series of high-temperature triaxial compression experiments.

Journal ArticleDOI
TL;DR: Results show that N-nonyl-deoxynojirimycin has an antiviral effect on flavivirus infection, likely through interference with virus replication at the posttranslational modification level, occurring mainly in the ER.
Abstract: Endoplasmic reticulum (ER) alpha-glucosidase inhibitors, which block the trimming step of N-linked glycosylation, have been shown to eliminate the production of several ER-budding viruses. Here we investigated the effects of one such inhibitor, N-nonyl-deoxynojirimycin (NN-DNJ), a 9-carbon alkyl iminosugar derivative, on infection by Japanese encephalitis virus (JEV) and dengue virus serotype 2 (DEN-2). In the presence of NN-DNJ, JEV and DEN-2 infections were suppressed in a dose-dependent manner. This inhibitory effect appeared to influence DEN-2 infection more than JEV infection, since lower concentrations of NN-DNJ substantially blocked DEN-2 replication. Secretion of the flaviviral glycoproteins E and NS1 was greatly reduced, and levels of DEN-2 viral RNA replication measured by fluorogenic reverse transcription-PCR were also decreased, by NN-DNJ. Notably, the viral glycoproteins, prM, E, and NS1 were found to associate transiently with the ER chaperone calnexin, and this interaction was affected by NN-DNJ, suggesting a potential role of calnexin in the folding of flaviviral glycoproteins. Additionally, in a mouse model of lethal challenge by JEV infection, oral delivery of NN-DNJ reduced the mortality rate. These findings show that NN-DNJ has an antiviral effect on flavivirus infection, likely through interference with virus replication at the posttranslational modification level, occurring mainly in the ER.

Journal ArticleDOI
TL;DR: A kinetic analysis of ERK2 dephosphorylation by protein phosphatases using a continuous spectrophotometric enzyme-coupled assay provides biochemical evidence that proteinosphatases display exquisite specificity in their substrate recognition and implicate HePTP, MKP3, and PP2A as ERK1 phosphatase as well as Ser/Thr protein phosph atases.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the impacts of tropospheric aerosols on the evolution of the atmospheric boundary layer (ABL) for dry subsiding regions by conducting simulations with a high-resolution ABL model.
Abstract: [1] This study investigates the impacts of tropospheric aerosols on the evolution of the atmospheric boundary layer (ABL) for dry subsiding regions by conducting simulations with a high-resolution ABL model. The scattering and absorption of aerosols diminish the surface radiation, inhibiting the sensible heat flux and evaporation and inducing feedbacks such as the enhanced stratification and change in relative humidity in the surface layer. The reduced sensible heat due to aerosol backscattering lowers the air temperature and suppresses the growth of the ABL. The resultant reduction of entrainment heating contributes to an additional cooling. The decreased entrainment drying competes with the reduced surface evaporation, so that the net effect can be either an increase or a decrease of the ABL moisture, depending on the soil moisture. Aerosol absorption decreases the turbulent heating but simultaneously increases the solar heating, increasing the air temperature and decreasing the strength of capping inversion. The resultant rise of the top of the ABL compensates the lowering due to the reduced buoyancy flux. With strong aerosol absorption, the increased entrainment heating enhances the ABL warming. Both the increased entrainment drying and the reduced evaporation decrease the ABL moisture. The increased warmth and dryness of the ABL imply that absorbing aerosols within the ABL decrease the probability of formation of boundary layer clouds, causing additional warming through cloud-feedbacks. The results are sensitive to the vertical distribution of absorbing aerosols. Absorbing aerosol above the ABL increases the strength of capping inversion and reduces the top of the ABL, hence decreasing the entrainment drying and moistening the ABL.