In vivo expression of the lacY gene in two segments leads to functional lac permease

International Nuclear Information System (INIS)

Bibi, E.; Kaback, H.R.

1990-01-01

The lacY gene of Escherichia coli was cut into two approximately equal-size fragments with Afl II and subcloned individually or together under separate lac operator/promoters in plasmid pT7-5. Under these conditions, lac permease is expressed in two portions: (i) the N-terminal portion (the N terminus, the first six putative transmembrane helices, and most of putative loop 7) and (ii) the C-terminal portion (the last six putative transmembrane helices and the C terminus). Cells harboring pT7-5 encoding both fragments transport lactose at about 30% the rate of cells expressing intact permease to a comparable steady-state level of accumulation. In contrast, cells expressing either half of the permease independently do not transport lactose. As judged by [ 35 S]methionine labeling and immunoblotting, intact permease in completely absent from the membrane of cells expressing lacY fragments either individually or together. Thus, transport activity must result from an association between independently synthesized pieces of lac permease. When the gene fragments are expressed individually, the N-terminal portion of the permease is observed inconsistently, and the C-terminal portion is not observed. When the gene fragments are expressed together, polypeptides identified as the N- and C-terminal moieties of the permease are found in the membrane. It is concluded that the N- or C-terminal halves of lac permease are proteolyzed when synthesized independently and that association between the two complementing polypeptides leads to a more stable, catalytically active complex

Identification and characterization of trimethylamine N-oxide (TMAO) demethylase and TMAO permease in Methylocella silvestris BL2

OpenAIRE

Zhu, Yijun; Jameson, Eleanor; Parslow, Rosemary A.; Lidbury, Ian; Fu, Tiantian; Dafforn, Tim; Schäfer, Hendrik; Chen, Yin

2014-01-01

Methylocella silvestris, an alphaproteobacterium isolated from a forest soil, can grow on trimethylamine N-oxide (TMAO) as a sole nitrogen source, however, the molecular and biochemical mechanisms underpinning its growth remain unknown. Marker-exchange mutagenesisenabled the identification of several genes involved in TMAO metabolism, including Msil_3606, a permease of the amino acids-polyamine (APC) superfamily, and Msil_3603, consisting of anN-terminal domain of unknown function (DUF1989) a...

Kinetic Analysis of Lactose Exchange in Proteoliposomes Reconstituted with Purified lac Permease

NARCIS (Netherlands)

Lolkema, Julius S.; Carrasco, Nancy; Kaback, H. Ronald

1991-01-01

Lactose exchange catalyzed by purified lac permease reconstituted into proteoliposomes was analyzed with unequal concentrations of lactose on either side of the membrane and at low pH so as to prevent equilibration of the two pools. Exchange with external concentrations below 1.0 mM is a

Genetic analysis of amino acid transport in the facultatively heterotrophic cyanobacterium Synechocystis sp. Strain 6803

International Nuclear Information System (INIS)

Labarre, J.; Thuriaux, P.; Chauvat, F.

1987-01-01

The existence of active transport systems (permeases) operating on amino acids in the photoautotrophic cyanobacterium Synechocystis sp. strain 6803 was demonstrated by following the initial rates of uptake with 14 C-labeled amino acids, measuring the intracellular pools of amino acids, and isolating mutants resistant to toxic amino acids. One class of mutants (Pfa1) corresponds to a regulatory defect in the biosynthesis of the aromatic amino acids, but two other classes (Can1 and Aza1) are defective in amino acid transport. The Can1 mutants are defective in the active transport of three basic amino acids (arginine, histidine, and lysine) and in one of two transport systems operating on glutamine. The Aza1 mutants are not affected in the transport of the basic amino acids but have lost the capacity to transport all other amino acids except glutamate. The latter amino acid is probably transported by a third permease which could be identical to the Can1-independent transport operating on glutamine. Thus, genetic evidence suggests that strain 6803 has only a small number of amino acid transport systems with fairly broad specificity and that, with the exception of glutamine, each amino acid is accumulated by only one major transport system. Compared with heterotrophic bacteria such as Escherichia coli, these permeases are rather inefficient in terms of affinity (apparent K/sub m/ ranging from 6 to 60 μM) and of V/sub max/

NCBI nr-aa BLAST: CBRC-TTRU-01-0084 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-TTRU-01-0084 ref|ZP_03665674.1| amino acid permease [Francisella tularensis su...bsp. tularensis MA00-2987] ref|ZP_04986598.1| amino acid permease [Francisella tularensis subsp. tularensis ...FSC033] ref|ZP_05247618.1| amino acid permease [Francisella tularensis subsp. tularensis MA00-2987] gb|EDN34...490.1| amino acid permease [Francisella tularensis subsp. tularensis FSC033] gb|E...ET19343.1| amino acid permease [Francisella tularensis subsp. tularensis MA00-2987] ZP_03665674.1 0.22 27% ...

Characterization of the Phthalate Permease OphD from Burkholderia cepacia ATCC 17616†

OpenAIRE

Chang, Hung-Kuang; Zylstra, Gerben J.

1999-01-01

The ophD gene, encoding a permease for phthalate transport, was cloned from Burkholderia cepacia ATCC 17616. Expression of the gene in Escherichia coli results in the ability to transport phthalate rapidly into the cell. Uptake inhibition experiments show that 4-hydroxyphthalate, 4-chlorophthalate, 4-methylphthalate, and cinchomeronate compete for the phthalate permease. An ophD knockout mutant of 17616 grows slightly more slowly on phthalate but is still able to take up phthalate at rates eq...

Conserved oligopeptide permeases modulate sporulation initiation in Clostridium difficile.

Science.gov (United States)

Edwards, Adrianne N; Nawrocki, Kathryn L; McBride, Shonna M

2014-10-01

The anaerobic gastrointestinal pathogen Clostridium difficile must form a metabolically dormant spore to survive in oxygenic environments and be transmitted from host to host. The regulatory factors by which C. difficile initiates and controls the early stages of sporulation in C. difficile are not highly conserved in other Clostridium or Bacillus species. Here, we investigated the role of two conserved oligopeptide permeases, Opp and App, in the regulation of sporulation in C. difficile. These permeases are known to positively affect sporulation in Bacillus species through the import of sporulation-specific quorum-sensing peptides. In contrast to other spore-forming bacteria, we discovered that inactivating these permeases in C. difficile resulted in the earlier expression of early sporulation genes and increased sporulation in vitro. Furthermore, disruption of opp and app resulted in greater virulence and increased the amounts of spores recovered from feces in the hamster model of C. difficile infection. Our data suggest that Opp and App indirectly inhibit sporulation, likely through the activities of the transcriptional regulator SinR and its inhibitor, SinI. Taken together, these results indicate that the Opp and App transporters serve a different function in controlling sporulation and virulence in C. difficile than in Bacillus subtilis and suggest that nutrient availability plays a significant role in pathogenesis and sporulation in vivo. This study suggests a link between the nutritional status of the environment and sporulation initiation in C. difficile. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

A putative role for amino acid permeases in sink-source communication of barley tissues uncovered by RNA-seq

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Kohl Stefan

2012-08-01

Full Text Available Abstract Background The majority of nitrogen accumulating in cereal grains originates from proteins remobilised from vegetative organs. However, interactions between grain filling and remobilisation are poorly understood. We used transcriptome large-scale pyrosequencing of flag leaves, glumes and developing grains to identify cysteine peptidase and N transporter genes playing a role in remobilisation and accumulation of nitrogen in barley. Results Combination of already known and newly derived sequence information reduced redundancy, increased contig length and identified new members of cysteine peptidase and N transporter gene families. The dataset for N transporter genes was aligned with N transporter amino acid sequences of rice and Arabidopsis derived from Aramemnon database. 57 AAT, 45 NRT1/PTR and 22 OPT unigenes identified by this approach cluster to defined subgroups in the respective phylogenetic trees, among them 25 AAT, 8 NRT1/PTR and 5 OPT full-length sequences. Besides, 59 unigenes encoding cysteine peptidases were identified and subdivided into different families of the papain cysteine peptidase clade. Expression profiling of full-length AAT genes highlighted amino acid permeases as the group showing highest transcriptional activity. HvAAP2 and HvAAP6 are highly expressed in vegetative organs whereas HvAAP3 is grain-specific. Sequence similarities cluster HvAAP2 and the putative transporter HvAAP6 together with Arabidopsis transporters, which are involved in long-distance transfer of amino acids. HvAAP3 is closely related to AtAAP1 and AtAAP8 playing a role in supplying N to developing seeds. An important role in amino acid re-translocation can be considered for HvLHT1 and HvLHT2 which are specifically expressed in glumes and flag leaves, respectively. PCA and K-means clustering of AAT transcript data revealed coordinate developmental stages in flag leaves, glumes and grains. Phloem-specific metabolic compounds are proposed that

Interdomain interactions in the mannitol permease of E-coli

NARCIS (Netherlands)

Meijberg, W; Schuurman-Wolters, GK; Robillard, GT; Ladbury, E.; Chowdhry, B.Z.

1998-01-01

The mannitol permease of E. coli, Enzyme IImannitol, catalyses the concomitant phosphorylation and transport of mannitol across the cytoplasmic membrane. The protein consists of three domains, one N-terminal transmembrane domain (C) and two cytoplasmic domains, A and B. During the catalytic cycle

The ArfGAP2/3 Glo3 and ergosterol collaborate in transport of a subset of cargoes

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Alejandro F. Estrada

2015-07-01

Full Text Available Proteins reach the plasma membrane through the secretory pathway in which the trans Golgi network (TGN acts as a sorting station. Transport from the TGN to the plasma membrane is maintained by a number of different pathways that act either directly or via the endosomal system. Here we show that a subset of cargoes depends on the ArfGAP2/3 Glo3 and ergosterol to maintain their proper localization at the plasma membrane. While interfering with neither ArfGAP2/3 activity nor ergosterol biosynthesis individually significantly altered plasma membrane localization of the tryptophan transporter Tat2, the general amino acid permease Gap1 and the v-SNARE Snc1, in a Δglo3 Δerg3 strain those proteins accumulated in internal endosomal structures. Export from the TGN to the plasma membrane and recycling from early endosomes appeared unaffected as the chitin synthase Chs3 that travels along these routes was localized normally. Our data indicate that a subset of proteins can reach the plasma membrane efficiently but after endocytosis becomes trapped in endosomal structures. Our study supports a role for ArfGAP2/3 in recycling from endosomes and in transport to the vacuole/lysosome.

Contribution of chloride channel permease to fluoride resistance in Streptococcus mutans.

Science.gov (United States)

Murata, Takatoshi; Hanada, Nobuhiro

2016-06-01

Genes encoding fluoride transporters have been identified in bacterial and archaeal species. The genome sequence of the cariogenic Streptococcus mutans bacteria suggests the presence of a putative fluoride transporter, which is referred to as a chloride channel permease. Two homologues of this gene (GenBank locus tags SMU_1290c and SMU_1289c) reside in tandem in the genome of S. mutans The aim of this study was to determine whether the chloride channel permeases contribute to fluoride resistance. We constructed SMU_1290c- and SMU_1289c-knockout S. mutans UA159 strains. We also constructed a double-knockout strain lacking both genes. SMU_1290c or SMU_1289c was transformed into a fluoride transporter- disrupted Escherichia coli strain. All bacterial strains were cultured under appropriate conditions with or without sodium fluoride, and fluoride resistance was evaluated. All three gene-knockout S. mutans strains showed lower resistance to sodium fluoride than did the wild-type strain. No significant changes in resistance to other sodium halides were recognized between the wild-type and double-knockout strains. Both SMU_1290c and SMU_1289c transformation rescued fluoride transporter-disrupted E. coli cell from fluoride toxicity. We conclude that the chloride channel permeases contribute to fluoride resistance in S. mutans. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

TOR induced resistance to toxic adenosine analogs in Leishmania brought about by the internalization and degradation of the adenosine permease

Science.gov (United States)

Detke, Siegfried

2007-01-01

TOR is an atypical multidrug resistance protein present in the human protozoan parasite, Leishmania. Resistance to the toxic adenosine analog tubercidin was brought about by redirecting the adenosine permease from the plasma membrane to the multivesicular tubule lysosome. The cells became resistant to tubercidin because they were unable to take up and accumulate this toxic purine. The domain which was recognized by TOR in this internalization pathway was identified by expressing portions of this transporter in Leishmania and assessing whether they were capable of hindering the multidrug resistance capability of TOR. This approach identified the adenosine permease region spanning Met289 to Trp305. This region was also the epitope recognized by the internalization mechanism. An internal deletion mutant lacking Met289-Trp305 was functionally active but could no longer be internalized in cells with high TOR levels. The internalization and altered trafficking of the adenosine permease by TOR was observed in yeast and human embryonic kidney cells co-expressing these two Leishmania proteins indicating that the internalization process was conserved in evolutionary diverse organisms. The inability of Saccharomyces with a temperature sensitive ubiquitin ligase to internalize adenosine permease suggested that ubiquitination was involved in this altered trafficking. PMID:17428463

NCBI nr-aa BLAST: CBRC-SARA-01-1753 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-SARA-01-1753 ref|YP_001476411.1| amino acid permease-associated region [Serratia proteam...aculans 568] gb|ABV39283.1| amino acid permease-associated region [Serratia proteamaculans 568] YP_001476411.1 0.83 35% ...

NCBI nr-aa BLAST: CBRC-AGAM-07-0010 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-AGAM-07-0010 ref|YP_001141362.1| amino acid permease [Aeromonas salmonicida subsp. salmon...icida A449] gb|ABO89614.1| amino acid permease [Aeromonas salmonicida subsp. salmonicida A449] YP_001141362.1 1e-132 96% ...

NCBI nr-aa BLAST: CBRC-DDIS-05-0159 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DDIS-05-0159 ref|YP_001124941.1| Amino acid permease [Geobacillus thermodenitr...ificans NG80-2] gb|ABO66196.1| Amino acid permease [Geobacillus thermodenitrificans NG80-2] YP_001124941.1 4e-49 39% ...

NCBI nr-aa BLAST: CBRC-CREM-01-1331 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CREM-01-1331 ref|YP_001479441.1| amino acid permease-associated region [Serratia proteam...aculans 568] gb|ABV42313.1| amino acid permease-associated region [Serratia proteamaculans 568] YP_001479441.1 5e-75 52% ...

NCBI nr-aa BLAST: CBRC-XTRO-01-0514 [SEVENS

Lifescience Database Archive (English)

Full Text Available modenitrificans NG80-2] gb|ABO66879.1| Branched-chain amino acid ABC transporter (permease) [Geobacillus thermodenitrificans NG80-2] YP_001125624.1 2e-97 62% ... ...CBRC-XTRO-01-0514 ref|YP_001125624.1| Branched-chain amino acid ABC transporter (permease) [Geobacillus ther

Cationic amino acid uptake constitutes a metabolic regulation mechanism and occurs in the flagellar pocket of Trypanosoma cruzi.

Directory of Open Access Journals (Sweden)

Mariana R Miranda

Full Text Available Trypanosomatids' amino acid permeases are key proteins in parasite metabolism since they participate in the adaptation of parasites to different environments. Here, we report that TcAAP3, a member of a Trypanosoma cruzi multigene family of permeases, is a bona fide arginine transporter. Most higher eukaryotic cells incorporate cationic amino acids through a single transporter. In contrast, T. cruzi can recognize and transport cationic amino acids by mono-specific permeases since a 100-fold molar excess of lysine could not affect the arginine transport in parasites that over-express the arginine permease (TcAAP3 epimastigotes. In order to test if the permease activity regulates downstream processes of the arginine metabolism, the expression of the single T. cruzi enzyme that uses arginine as substrate, arginine kinase, was evaluated in TcAAP3 epimastigotes. In this parasite model, intracellular arginine concentration increases 4-folds and ATP level remains constant until cultures reach the stationary phase of growth, with decreases of about 6-folds in respect to the controls. Interestingly, Western Blot analysis demonstrated that arginine kinase is significantly down-regulated during the stationary phase of growth in TcAAP3 epimastigotes. This decrease could represent a compensatory mechanism for the increase in ATP consumption as a consequence of the displacement of the reaction equilibrium of arginine kinase, when the intracellular arginine concentration augments and the glucose from the medium is exhausted. Using immunofluorescence techniques we also determined that TcAAP3 and the specific lysine transporter TcAAP7 co-localize in a specialized region of the plasma membrane named flagellar pocket, staining a single locus close to the flagellar pocket collar. Taken together these data suggest that arginine transport is closely related to arginine metabolism and cell energy balance. The clinical relevance of studying trypanosomatids' permeases

Functional analysis of human aromatic amino acid transporter MCT10/TAT1 using the yeast Saccharomyces cerevisiae.

Science.gov (United States)

Uemura, Satoshi; Mochizuki, Takahiro; Kurosaka, Goyu; Hashimoto, Takanori; Masukawa, Yuki; Abe, Fumiyoshi

2017-10-01

Tryptophan is an essential amino acid in humans and an important serotonin and melatonin precursor. Monocarboxylate transporter MCT10 is a member of the SLC16A family proteins that mediates low-affinity tryptophan transport across basolateral membranes of kidney, small intestine, and liver epithelial cells, although the precise transport mechanism remains unclear. Here we developed a simple functional assay to analyze tryptophan transport by human MCT10 using a deletion mutant for the high-affinity tryptophan permease Tat2 in Saccharomyces cerevisiae. tat2Δtrp1 cells are defective in growth in YPD medium because tyrosine present in the medium competes for the low-affinity tryptophan permease Tat1 with tryptophan. MCT10 appeared to allow growth of tat2Δtrp1 cells in YPD medium, and accumulate in cells deficient for Rsp5 ubiquitin ligase. These results suggest that MCT10 is functional in yeast, and is subject to ubiquitin-dependent quality control. Whereas growth of Tat2-expressing cells was significantly impaired by neutral pH, that of MCT10-expressing cells was nearly unaffected. This property is consistent with the transport mechanism of MCT10 via facilitated diffusion without a need for pH gradient across the plasma membrane. Single-nucleotide polymorphisms (SNPs) are known to occur in the human MCT10 coding region. Among eight SNP amino acid changes in MCT10, the N81K mutation completely abrogated tryptophan import without any abnormalities in the expression or localization. In the MCT10 modeled structure, N81 appeared to protrude into the putative trajectory of tryptophan. Plasma membrane localization of MCT10 and the variant proteins was also verified in human embryonic kidney 293T cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics.

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Morgan N Price

2018-01-01

Full Text Available For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. We studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fill 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.

Profile of preoperative fecal organic acids closely predicts the incidence of postoperative infectious complications after major hepatectomy with extrahepatic bile duct resection: Importance of fecal acetic acid plus butyric acid minus lactic acid gap.

Science.gov (United States)

Yokoyama, Yukihiro; Mizuno, Takashi; Sugawara, Gen; Asahara, Takashi; Nomoto, Koji; Igami, Tsuyoshi; Ebata, Tomoki; Nagino, Masato

2017-10-01

To investigate the association between preoperative fecal organic acid concentrations and the incidence of postoperative infectious complications in patients undergoing major hepatectomy with extrahepatic bile duct resection for biliary malignancies. The fecal samples of 44 patients were collected before undergoing hepatectomy with bile duct resection for biliary malignancies. The concentrations of fecal organic acids, including acetic acid, butyric acid, and lactic acid, and representative fecal bacteria were measured. The perioperative clinical characteristics and the concentrations of fecal organic acids were compared between patients with and without postoperative infectious complications. Among 44 patients, 13 (30%) developed postoperative infectious complications. Patient age and intraoperative bleeding were significantly greater in patients with postoperative infectious complications compared with those without postoperative infectious complications. The concentrations of fecal acetic acid and butyric acid were significantly less, whereas the concentration of fecal lactic acid tended to be greater in the patients with postoperative infectious complications. The calculated gap between the concentrations of fecal acetic acid plus butyric acid minus lactic acid gap was less in the patients with postoperative infectious complications (median 43.5 vs 76.1 μmol/g of feces, P = .011). Multivariate analysis revealed that an acetic acid plus butyric acid minus lactic acid gap acid profile (especially low acetic acid, low butyric acid, and high lactic acid) had a clinically important impact on the incidence of postoperative infectious complications in patients undergoing major hepatectomy with extrahepatic bile duct resection. Copyright © 2017. Published by Elsevier Inc.

Identification and characterization of trimethylamine N-oxide (TMAO) demethylase and TMAO permease in Methylocella silvestris BL2.

Science.gov (United States)

Zhu, Yijun; Jameson, Eleanor; Parslow, Rosemary A; Lidbury, Ian; Fu, Tiantian; Dafforn, Timothy R; Schäfer, Hendrik; Chen, Yin

2014-10-01

Methylocella silvestris, an alphaproteobacterium isolated from a forest soil, can grow on trimethylamine N-oxide (TMAO) as a sole nitrogen source; however, the molecular and biochemical mechanisms underpinning its growth remain unknown. Marker-exchange mutagenesis enabled the identification of several genes involved in TMAO metabolism, including Msil_3606, a permease of the amino acids-polyamine (APC) superfamily, and Msil_3603, consisting of an N-terminal domain of unknown function (DUF1989) and a C-terminal tetrahydrofolate-binding domain. Null mutants of Msil_3603 and Msil_3606 can no longer grow on TMAO. Purified Msil_3603 from recombinant Escherichia coli can convert TMAO to dimethylamine and formaldehyde (1 TMAO → 1 dimethylamine + 1 formaldehyde), confirming that it encodes a bona fide TMAO demethylase (Tdm). Tdm of M. silvestris and eukaryotic Tdms have no sequence homology and contrasting characteristics. Recombinant Tdm of M. silvestris appears to be hexameric, has a high affinity for TMAO (Km = 3.3 mM; Vmax = 21.7 nmol min(-1)  mg(-1) ) and only catalyses demethylation of TMAO and a structural homologue, dimethyldodecylamine N-oxide. Our study has contributed to the understanding of the genetic and biochemical mechanisms for TMAO degradation in M. silvestris. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

[Recombinant human gapM1 expressed in Pichia pastoris and its anti-diabetic effect].

Science.gov (United States)

Mei, Xiang; Du, Renqian; Li, Xi; Huang, Haiyan; Yu, Min; Tang, Qiqun

2009-08-01

Adiponectin is an adipokine predominantly synthesized and secreted by adipocytes in the white adipose tissue, and it can lower the blood glucose level and increase free fatty acid oxidation. In the current study, we developed the globular domain of adiponectin (gapM1) to treat type II diabetes. In both flask and fermentor, we cultivated Pichia pastoris expressing recombinant gapM1 and established the purification procedure by using gel filtration and anion exchange chromatography. To evaluate the biological activity of recombinant gapM1, we used rat type II diabetes model fed high-fat diet in combination with low-dose STZ (Streptozocin) induction. We purified 200 mg gapM1 with purity of 96% from 10 liters of supernatant. The recombinant gapM1 significantly lowered blood glucose (34.2%), serum triglyceride (79.6%) and total cholesterol (62.1%) in type II diabetes induced rat. Therefore, the recombinant human gapM1 is successfully expressed in Pichia pastoris and effectively treated type II diabetes in rat models.

Effects of spermine on the detection of induced forward mutation at the CAN1 locus in yeast: evidence for selection against canavanine-resistant mutants

Energy Technology Data Exchange (ETDEWEB)

McDougall, K.J.; Lemontt, J.F.

1979-01-01

The effect of exogenous spermine tetrahydrochloride (0.5 mg/ml) on hydrazine- and nitrous acid-induced forward mutation to canavanine resistance (CAN1 ..-->.. can1, normal to defective arginine permease) was examined in stationary-phase haploid Saccharomyces cerevisiae. Post-treatment cell division (specifically DNA replication) is required for hydrazine mutagenesis at this locus, whereas nitrous acid mutagenesis exhibits, in addition, a significant post-treatment-independent component.

An Expanding Role For Purine Uptake Permease (PUP -like Transporters In Plant Secondary Metabolism.

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John G. Jelesko

2012-05-01

Full Text Available For the past decade, our understanding of the plant purine uptake permease (PUP transporter family of was primarily oriented on purine nucleobase substrates and their tissue-specific expression patterns in Arabidopsis. However, a tobacco PUP-like homolog demonstrating nicotine uptake permease (NUP activity was recently shown to affect both nicotine metabolism and root cell growth. These new findings expand the physiological role for PUP-like transporters to include plant secondary metabolism. Molecular evolution analyses of PUP-like transporters indicate they are distinct group within an ancient super family of drug and metabolite transporters (DMTs. The PUP-like family originated during terrestrial plant evolution sometime between the bryophytes and the lycophytes. A phylogenetic analysis indicates that the PUP-like transporters were likely were derived from a pre-existing nucleotide sugar transporter family within the DMT super family. Within the lycophyte Selaginella, there are three paralogous groups of PUP-like transporters. One of the three PUP-like paralogous groups showed an extensive pattern of gene duplication and diversification within the angiosperm lineage, whereas the other two more ancestral PUP-like paralogous groups did not. Biochemical characterization of four closely-related PUP-like paralogs together with model-based phylogenetic analyses indicate both subfunctionalization and neofunctionalization during the molecular evolution of angiosperm PUP-like transporters. These findings suggest that members of the PUP-like family of DMT transporters are likely involved in diverse primary and secondary plant metabolic pathways.

Sugar transport across lactose permease probed by steered molecular dynamics

DEFF Research Database (Denmark)

Jensen, Morten Østergaard; Yin, Ying; Tajkhorshid, Emad

2007-01-01

Escherichia coli lactose permease (LacY) transports sugar across the inner membrane of the bacterium using the proton motive force to accumulate sugar in the cytosol. We have probed lactose conduction across LacY using steered molecular dynamics, permitting us to follow molecular and energetic...... details of lactose interaction with the lumen of LacY during its permeation. Lactose induces a widening of the narrowest parts of the channel during permeation, the widening being largest within the periplasmic half-channel. During permeation, the water-filled lumen of LacY only partially hydrates lactose......, forcing it to interact with channel lining residues. Lactose forms a multitude of direct sugar-channel hydrogen bonds, predominantly with residues of the flexible N-domain, which is known to contribute a major part of LacY's affinity for lactose. In the periplasmic half-channel lactose predominantly...

[Disorders of the acid-base balance and the anion gap].

Science.gov (United States)

Kimmel, Martin; Alscher, Mark Dominik

2016-10-01

The regulation of the acid-base balance and pH is critical for the organism. The most important buffer system is CO 2 / HCO 3 - . The kidney controls systemic bicarbonate and therefore the metabolic regulation and the lung is relevant for respiratory regulation by an effective CO 2 elimination. There are four acid-base disorders with two metabolic and two respiratory disorders (acidosis and alkalosis). The anion gap enables a further workup of metabolic acidosis. © Georg Thieme Verlag KG Stuttgart · New York.

Characterization of a second physiologically relevant lactose permease gene (lacpB) in Aspergillus nidulans.

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Fekete, Erzsébet; Orosz, Anita; Kulcsár, László; Kavalecz, Napsugár; Flipphi, Michel; Karaffa, Levente

2016-05-01

In Aspergillus nidulans, uptake rather than hydrolysis is the rate-limiting step of lactose catabolism. Deletion of the lactose permease A-encoding gene (lacpA) reduces the growth rate on lactose, while its overexpression enables faster growth than wild-type strains are capable of. We have identified a second physiologically relevant lactose transporter, LacpB. Glycerol-grown mycelia from mutants deleted for lacpB appear to take up only minute amounts of lactose during the first 60 h after a medium transfer, while mycelia of double lacpA/lacpB-deletant strains are unable to produce new biomass from lactose. Although transcription of both lacp genes was strongly induced by lactose, their inducer profiles differ markedly. lacpA but not lacpB expression was high in d-galactose cultures. However, lacpB responded strongly also to β-linked glucopyranose dimers cellobiose and sophorose, while these inducers of the cellulolytic system did not provoke any lacpA response. Nevertheless, lacpB transcript was induced to higher levels on cellobiose in strains that lack the lacpA gene than in a wild-type background. Indeed, cellobiose uptake was faster and biomass formation accelerated in lacpA deletants. In contrast, in lacpB knockout strains, growth rate and cellobiose uptake were considerably reduced relative to wild-type, indicating that the cellulose and lactose catabolic systems employ common elements. Nevertheless, our permease mutants still grew on cellobiose, which suggests that its uptake in A. nidulans prominently involves hitherto unknown transport systems.

Insight on specificity of uracil permeases of the NAT/NCS2 family from analysis of the transporter encoded in the pyrimidine utilization operon of Escherichia coli.

Science.gov (United States)

Botou, Maria; Lazou, Panayiota; Papakostas, Konstantinos; Lambrinidis, George; Evangelidis, Thomas; Mikros, Emmanuel; Frillingos, Stathis

2018-04-01

The uracil permease UraA of Escherichia coli is a structurally known prototype for the ubiquitous Nucleobase-Ascorbate Transporter (NAT) or Nucleobase-Cation Symporter-2 (NCS2) family and represents a well-defined subgroup of bacterial homologs that remain functionally unstudied. Here, we analyze four of these homologs, including RutG of E. coli which shares 35% identity with UraA and is encoded in the catabolic rut (pyrimidine utilization) operon. Using amplified expression in E. coli K-12, we show that RutG is a high-affinity permease for uracil, thymine and, at low efficiency, xanthine and recognizes also 5-fluorouracil and oxypurinol. In contrast, UraA and the homologs from Acinetobacter calcoaceticus and Aeromonas veronii are permeases specific for uracil and 5-fluorouracil. Molecular docking indicates that thymine is hindered from binding to UraA by a highly conserved Phe residue which is absent in RutG. Site-directed replacement of this Phe with Ala in the three uracil-specific homologs allows high-affinity recognition and/or transport of thymine, emulating the RutG profile. Furthermore, all RutG orthologs from enterobacteria retain an Ala at this position, implying that they can use both uracil and thymine and, possibly, xanthine as substrates and provide the bacterial cell with a range of catabolizable nucleobases. © 2018 John Wiley & Sons Ltd.

Functional Characterization of PaLAX1, a Putative Auxin Permease, in Heterologous Plant Systems1[W][OA

Science.gov (United States)

Hoyerová, Klára; Perry, Lucie; Hand, Paul; Laňková, Martina; Kocábek, Tomáš; May, Sean; Kottová, Jana; Pačes, Jan; Napier, Richard; Zažímalová, Eva

2008-01-01

We have isolated the cDNA of the gene PaLAX1 from a wild cherry tree (Prunus avium). The gene and its product are highly similar in sequences to both the cDNAs and the corresponding protein products of AUX/LAX-type genes, coding for putative auxin influx carriers. We have prepared and characterized transformed Nicotiana tabacum and Arabidopsis thaliana plants carrying the gene PaLAX1. We have proved that constitutive overexpression of PaLAX1 is accompanied by changes in the content and distribution of free indole-3-acetic acid, the major endogenous auxin. The increase in free indole-3-acetic acid content in transgenic plants resulted in various phenotype changes, typical for the auxin-overproducing plants. The uptake of synthetic auxin, 2,4-dichlorophenoxyacetic acid, was 3 times higher in transgenic lines compared to the wild-type lines and the treatment with the auxin uptake inhibitor 1-naphthoxyacetic acid reverted the changes caused by the expression of PaLAX1. Moreover, the agravitropic response could be restored by expression of PaLAX1 in the mutant aux1 plants, which are deficient in auxin influx carrier activity. Based on our data, we have concluded that the product of the gene PaLAX1 promotes the uptake of auxin into cells, and, as a putative auxin influx carrier, it affects the content and distribution of free endogenous auxin in transgenic plants. PMID:18184737

The composite N1 component to gaps in noise.

Science.gov (United States)

Pratt, Hillel; Bleich, Naomi; Mittelman, Nomi

2005-11-01

To indicate whether the double peaked N(1) to gaps in continuous white noise is a composite of onset and offset responses to transients or whether it reflects higher processing such as change or mismatch detection and to assess the role of attention in this process. Evoked potentials were recorded to two binaural stimulus types: (1) gaps of different durations randomly distributed in continuous white noise; and (2) click pairs at intervals identical to those between gap onsets and offsets in the continuous noise stimulus. Potentials to these stimuli were recorded while subjects read a text and while detecting gaps in noise or click pairs. Potentials were detected to all click pairs and to gaps of 5 ms or longer, corresponding to the subjects' psychoacoustic gap detection threshold. With long gap durations of 200-800 ms, distinct potentials to gap onset and gap offset were observed. The waveforms to all click pairs and to offsets of long gaps were similar and single-peaked, while potentials to gaps of 10 ms and longer, and potentials to onsets of long gaps were double-peaked, consisting of two N(1) negativities, 60 ms apart, irrespective of gap duration. The first (N(1a)), was more frontal in its distribution and similar to that of clicks. The second (N(1b)) peak's distribution was more central/temporal and its source locations and time course of activity were distinct. No effects of attention on any of the varieties and constituents of N(1) were observed. Comparing potentials to gap onsets, to click pairs and to gap offsets, suggests that potentials to gap onsets involve not only sound onset/offset responses (N(1), N(1a)) but also the subsequent pre-attentive perception of the cessation of an ongoing sound (N(1b)). We propose that N(1b) is distinct from change or mismatch detection and is associated with termination of an ongoing continuous stimulus. We propose to call it the N(egation)-process. A constituent of the N(1) complex is shown to be associated with the

Melibiose permease and alpha-galactosidase of Escherichia coli: Identification by selective labeling using a T7 RNA polymerase/promoter expression system

International Nuclear Information System (INIS)

Pourcher, T.; Bassilana, M.; Sarkar, H.K.; Kaback, H.R.; Leblanc, G.

1990-01-01

Identification and selective labeling of the melibiose permease and alpha-galactosidase in Escherichia coli, which are encoded by the melB and melA genes, respectively, have been accomplished by selectively labeling the two gene products with a T7 RNA polymerase expression system. Following generation of a novel EcoRI restriction site in the intergenic sequence between the two genes of the mel operon by oligonucleotide-directed, site-specific mutagenesis, melA and melB were separately inserted into plasmid pT7-6 of the T7 expression system. Expression of melB was markedly enhanced by placing a strong, synthetic ribosome binding site at an optimal distance upstream from the initiation codon of melB. Expression of cloned gene products was characterized functionally and by performing autoradiographic analysis on total cell, inner membrane, and cytoplasmic proteins from cells pulse labeled with (35S)methionine in the presence of rifampicin and resolved by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The results first confirm that alpha-galactosidase is a cytoplasmic protein with an Mr of 50K; in contrast, the membrane-bound melibiose permease is identified as a protein with an apparent Mr of 39K, a value significantly higher than that of 30K previously suggested

The serum anion gap in the evaluation of acid-base disorders: what are its limitations and can its effectiveness be improved?

Science.gov (United States)

Kraut, Jeffrey A; Nagami, Glenn T

2013-11-01

The serum anion gap has been utilized to identify errors in the measurement of electrolytes, to detect paraproteins, and, most relevant to the nephrologist, to evaluate patients with suspected acid-base disorders. In regard to the latter purpose, traditionally an increased anion gap is identified when it exceeds the upper limit of normal for a particular clinical laboratory measurement. However, because there is a wide range of normal values (often 8-10 mEq/L), an increase in anion concentration can be present in the absence of an increased anion gap. In addition, the type of retained anion can affect the magnitude of the increase in anion gap relative to change in serum [HCO3(-)] being greater with lactic acidosis compared with ketoacidosis. This review examines the methods of calculation of the serum anion gap in textbooks and published literature, the effect of perturbations other than changes in acid-base balance, and its effectiveness in identifying mild and more severe disturbances in acid-base balance. Limitations of the present methods of determining the normal anion gap and change in the anion gap are highlighted. The possibility of identifying the baseline value for individuals to optimize the use of the calculation in the detection of metabolic acidosis is suggested.

Long Chain Saturated and Unsaturated Carboxylic Acids: Filling a Large Gap of Knowledge in Their Enthalpies of Formation.

Science.gov (United States)

Rogers, Donald W; Zavitsas, Andreas A

2017-01-06

Despite their abundance in nature and their importance in biology, medicine, nutrition, and in industry, gas phase enthalpies of formation of many long chain saturated and unsaturated fatty acids and of dicarboxylic acids are either unavailable or have been estimated with large uncertainties. Available experimental values for stearic acid show a spread of 68 kJ mol -1 . This work fills the knowledge gap by obtaining reliable values by quantum theoretical calculations using G4 model chemistry. Compounds with up to 20 carbon atoms are treated. The theoretical results are in excellent agreement with well established experimental values when such values exist, and they provide a large number of previously unavailable values.

Effect of Detergents on Galactoside Binding by Melibiose Permeases.

Science.gov (United States)

Amin, Anowarul; Hariharan, Parameswaran; Chae, Pil Seok; Guan, Lan

2015-09-29

The effect of various detergents on the stability and function of the melibiose permeases of Escherichia coli (MelBEc) and Salmonella typhimurium (MelBSt) was studied. In n-dodecyl-β-d-maltoside (DDM) or n-undecyl-β-d-maltoside (UDM), WT MelBSt binds melibiose with an affinity similar to that in the membrane. However, with WT MelBEc or MelBSt mutants (Arg141 → Cys, Arg295 → Cys, or Arg363 → Cys), galactoside binding is not detected in these detergents, but binding to the phosphotransferase protein IIA(Glc) is maintained. In the amphiphiles lauryl maltose neopentyl glycol (MNG-3) or glyco-diosgenin (GDN), galactoside binding with all of the MelB proteins is observed, with slightly reduced affinities. MelBSt is more thermostable than MelBEc, and the thermostability of either MelB is largely increased in MNG-3 or GDN. Therefore, the functional defect with DDM or UDM likely results from the relative instability of the sensitive MelB proteins, and stability, as well as galactoside binding, is retained in MNG-3 or GDN. Furthermore, isothermal titration calorimetry of melibiose binding with MelBSt shows that the favorable entropic contribution to the binding free energy is decreased in MNG-3, indicating that the conformational dynamics of MelB is restricted in this detergent.

Coarse-grained Simulations of Sugar Transport and Conformational Changes of Lactose Permease

Science.gov (United States)

Liu, Jin; Jewel, S. M. Yead; Dutta, Prashanta

2016-11-01

Escherichia coli lactose permease (LacY) actively transports lactose and other galactosides across cell membranes through lactose/H+ symport process. Lactose/H+ symport is a highly complex process that involves sugar translocation, H+ transfer, as well as large-scale protein conformational changes. The complete picture of lactose/H+ symport is largely unclear due to the complexity and multiscale nature of the process. In this work, we develop the force field for sugar molecules compatible with PACE, a hybrid and coarse-grained force field that couples the united-atom protein models with the coarse-grained MARTINI water/lipid. After validation, we implement the new force field to investigate the transport of a β-D-galactopyranosyl-1-thio- β-D-galactopyranoside (TDG) molecule across a wild-type LacY during lactose/H+ symport process. Results show that the local interactions between TDG and LacY at the binding pocket are consistent with the X-ray experiment. Protonation of Glu325 stabilizes the TDG and inward-facing conformation of LacY. Protonation of Glu269 induces a dramatic protein structural reorganization and causes the expulsion of TDG from LacY to both sides of the membrane. The structural changes occur primarily in the N-terminal domain of LacY. This work is supported by NSF Grants: CBET-1250107 and CBET -1604211.

Identification and Characterization of Novel Plant Adenylate Cyclases – The Arabidopsis Thaliana Potassium Uptake Permeases

KAUST Repository

Al-Younis, Inas M.

2018-05-01

Adenylyl Cyclases (ACs) catalyze the formation of the key universal second messenger adenosine 3’, 5’-cyclic monophosphate (cAMP) from adenosine 5’- triphosphate. Cyclic AMP participates in several signal transduction pathways and is present in bacteria and higher and lower eukaryotes including higher plants. Previous studies in plants have shown a role for cAMP in signal transduction during e.g. the cell cycle, elongation of the pollen tube and stimulation of protein kinase activity. More recently cAMP has been shown to play a role in stress responses. Interestingly, cAMP has also been shown to regulate ion transport in plant cells. Here we used a similar strategy that led to the discovery of the first guanylyl cyclase in plants that was based on the alignment of conserved and functionally assigned amino acids in the catalytic centre of annotated nucleotide cyclases from lower and higher eukaryotes, to identify a novel candidate ACs in Arabidopsis (Arabidopsis thaliana K+ Uptake 5 and 7). ATKUP5 and 7 are homologous to K+ uptake permeases (KUPs) from bacteria and high-affinity K+ transporters (HAKs) from fungi. The AC activity was investigated by recombinantly expressing the ATKUP5 and 7 AC domain in vitro and by complementation of an E. coli AC mutant (cyaA). Furthermore, ATKUP5 was tested for its ability to functionally complement a yeast mutant deficient in Trk1 and Trk2 high affinity potassium uptake transporters. Site-mutagenesis in the AC domain was used to test the effect of both functions in each other. Furthermore, ATKUP5 was characterized electrophysiologically in HEK-293 cells to characterize the nature of this transporter. The localization of the ATKUP5 in Arabidopsis was examined using a Green Fluorescent Protein (GFP) fusion with the ATKUP5 to determine whether ATKUP5 is expressed at the plasma or tonoplast membrane. Arabiodpsis thaliana of the wild type, overexpressing ATKUP5 and atkup5 mutant lines were used to examine phenotypic differences.

FOXC1 modulates MYOC secretion through regulation of the exocytic proteins RAB3GAP1, RAB3GAP2 and SNAP25.

Directory of Open Access Journals (Sweden)

Alexandra Rasnitsyn

Full Text Available The neurodegenerative disease glaucoma is one of the leading causes of blindness in the world. Glaucoma is characterized by progressive visual field loss caused by retinal ganglion cell (RGC death. Both surgical glaucoma treatments and medications are available, however, they only halt glaucoma progression and are unable to reverse damage. Furthermore, many patients do not respond well to treatments. It is therefore important to better understand the mechanisms involved in glaucoma pathogenesis. Patients with Axenfeld-Rieger syndrome (ARS offer important insight into glaucoma progression. ARS patients are at 50% risk of developing early onset glaucoma and respond poorly to treatments, even when surgical treatments are combined with medications. Mutations in the transcription factor FOXC1 cause ARS. Alterations in FOXC1 levels cause ocular malformations and disrupt stress response in ocular tissues, thereby contributing to glaucoma progression. In this study, using biochemical and molecular techniques, we show that FOXC1 regulates the expression of RAB3GAP1, RAB3GAP2 and SNAP25, three genes with central roles in both exocytosis and endocytosis, responsible for extracellular trafficking. FOXC1 positively regulates RAB3GAP1 and RAB3GAP2, while either increase or decrease in FOXC1 levels beyond its normal range results in decreased SNAP25. In addition, we found that FOXC1 regulation of RAB3GAP1, RAB3GAP2 and SNAP25 affects secretion of Myocilin (MYOC, a protein associated with juvenile onset glaucoma and steroid-induced glaucoma. The present work reveals that FOXC1 is an important regulator of exocytosis and establishes a new link between FOXC1 and MYOC-associated glaucoma.

Connecting Source with Sink: The Role of Arabidopsis AAP8 in Phloem Loading of Amino Acids1[OPEN

Science.gov (United States)

Santiago, James P.; Tegeder, Mechthild

2016-01-01

Allocation of large amounts of nitrogen to developing organs occurs in the phloem and is essential for plant growth and seed development. In Arabidopsis (Arabidopsis thaliana) and many other plant species, amino acids represent the dominant nitrogen transport forms in the phloem, and they are mainly synthesized in photosynthetically active source leaves. Following their synthesis, a broad spectrum of the amino nitrogen is actively loaded into the phloem of leaf minor veins and transported within the phloem sap to sinks such as developing leaves, fruits, or seeds. Controlled regulation of the source-to-sink transport of amino acids has long been postulated; however, the molecular mechanism of amino acid phloem loading was still unknown. In this study, Arabidopsis AMINO ACID PERMEASE8 (AAP8) was shown to be expressed in the source leaf phloem and localized to the plasma membrane, suggesting its function in phloem loading. This was further supported by transport studies with aap8 mutants fed with radiolabeled amino acids and by leaf exudate analyses. In addition, biochemical and molecular analyses revealed alterations in leaf nitrogen pools and metabolism dependent on the developmental stage of the mutants. Decreased amino acid phloem loading and partitioning to sinks led to decreased silique and seed numbers, but seed protein levels were unchanged, demonstrating the importance of AAP8 function for sink development rather than seed quality. Overall, these results show that AAP8 plays an important role in source-to-sink partitioning of nitrogen and that its function affects source leaf physiology and seed yield. PMID:27016446

Test of freonless operation of resistive plate chambers with glass electrodes--1 mm gas gap vs 2 mm gas gap

CERN Document Server

Sakaue, H; Takahashi, T; Teramoto, Y

2002-01-01

Non-freon gas mixtures (Ar/iso-C sub 4 H sub 1 sub 0) were tested as the chamber gas for 1 and 2 mm gas gap Resistive Plate Chambers (RPCs) with float glass as the resistive electrodes, operated in the streamer mode. With the narrower (1 mm) gas gap, streamer charge is reduced (approx 1/3), which reduces the dead time (and dead area), associated with each streamer, improving the detection efficiency. The best performance was obtained for two cases: Ar/iso-C sub 4 H sub 1 sub 0 =50/50 and 60/40. For the 50/50 mixture, a detection efficiency of better than 98% was obtained for the 1 mm gap RPC, while the efficiency was 95% for the 2 mm gap RPC, each operated as a double-gap RPC. The measured time resolution (rms) was 1.45+-0.05 (2.52+-0.09) ns for the 1 (2) mm gap RPC for the 50/50 mixture.

The Cellular Distribution of RanGAP1 Is Regulated by CRM1-Mediated Nuclear Export in Mammalian Cells.

Directory of Open Access Journals (Sweden)

Keith Cha

Full Text Available The Ran GTPase activating protein RanGAP1 plays an essential role in nuclear transport by stimulating RanGTP hydrolysis in the cytoplasmic compartment. In mammalian cells, unmodified RanGAP1 is predominantly cytoplasmic, whereas modification by small ubiquitin-related modifier protein (SUMO targets RanGAP1 to the cytoplasmic filaments of nuclear pore complex (NPC. Although RanGAP1 contains nine putative nuclear export signals and a nuclear localization signal, little is known if RanGAP1 shuttles between the nuclear and cytoplasmic compartments and how its primary localization in the cytoplasm and at the NPC is regulated. Here we show that inhibition of CRM1-mediated nuclear export using RNAi-knockdown of CRM1 and inactivation of CRM1 by leptomycin B (LMB results in nuclear accumulation of RanGAP1. LMB treatment induced a more robust redistribution of RanGAP1 from the cytoplasm to the nucleoplasm compared to CRM1 RNAi and also uniquely triggered a decrease or loss of RanGAP1 localization at the NPC, suggesting that LMB treatment is more effective in inhibiting CRM1-mediated nuclear export of RanGAP1. Our time-course analysis of LMB treatment reveals that the NPC-associated RanGAP1 is much more slowly redistributed to the nucleoplasm than the cytoplasmic RanGAP1. Furthermore, LMB-induced nuclear accumulation of RanGAP1 is positively correlated with an increase in levels of SUMO-modified RanGAP1, suggesting that SUMOylation of RanGAP1 may mainly take place in the nucleoplasm. Lastly, we demonstrate that the nuclear localization signal at the C-terminus of RanGAP1 is required for its nuclear accumulation in cells treated with LMB. Taken together, our results elucidate that RanGAP1 is actively transported between the nuclear and cytoplasmic compartments, and that the cytoplasmic and NPC localization of RanGAP1 is dependent on CRM1-mediated nuclear export.

Crystal structure of lactose permease in complex with an affinity inactivator yields unique insight into sugar recognition

Energy Technology Data Exchange (ETDEWEB)

Chaptal, Vincent; Kwon, Seunghyug; Sawaya, Michael R.; Guan, Lan; Kaback, H. Ronald; Abramson, Jeff (UCLA); (TTU)

2011-08-29

Lactose permease of Escherichia coli (LacY) with a single-Cys residue in place of A122 (helix IV) transports galactopyranosides and is specifically inactivated by methanethiosulfonyl-galactopyranosides (MTS-gal), which behave as unique suicide substrates. In order to study the mechanism of inactivation more precisely, we solved the structure of single-Cys122 LacY in complex with covalently bound MTS-gal. This structure exhibits an inward-facing conformation similar to that observed previously with a slight narrowing of the cytoplasmic cavity. MTS-gal is bound covalently, forming a disulfide bond with C122 and positioned between R144 and W151. E269, a residue essential for binding, coordinates the C-4 hydroxyl of the galactopyranoside moiety. The location of the sugar is in accord with many biochemical studies.

Sequence Classification: 567688 [

Lifescience Database Archive (English)

Full Text Available Non-TMB TMH Non-TMB TMB TMB Non-TMB >gi|15967001|ref|NP_387354.1| PUTATIVE AMINO-ACID TRANSPORT... SYSTEM PERMEASE ABC TRANSPORTER PROTEIN || http://www.ncbi.nlm.nih.gov/protein/15967001 ...

Multilevel regulation of an alpha-arrestin by glucose depletion controls hexose transporter endocytosis

Czech Academy of Sciences Publication Activity Database

Hovsepian, J.; Defenouillere, Q.; Albanese, V.; Váchová, Libuše; Garcia, C.; Palková, Zdena; Léon, S.

2017-01-01

Roč. 216, č. 6 (2017), s. 1811-1831 ISSN 0021-9525 R&D Projects: GA MŠk(CZ) LQ1604; GA ČR(CZ) GA15-08225S Institutional support: RVO:61388971 Keywords : YEAST SACCHAROMYCES-CEREVISIAE * BIMOLECULAR FLUORESCENCE COMPLEMENTATION * GAP1 PERMEASE UBIQUITYLATION Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 7.955, year: 2016

Sequence Classification: 565916 [

Lifescience Database Archive (English)

Full Text Available Non-TMB TMH Non-TMB TMB TMB Non-TMB >gi|15965229|ref|NP_385582.1| PROBABLE GENERAL L-AMINO ACID TRANSPORT... PERMEASE ABC TRANSPORTER PROTEIN || http://www.ncbi.nlm.nih.gov/protein/15965229 ...

The cyst nematode SPRYSEC protein RBP-1 elicits Gpa2- and RanGAP2-dependent plant cell death.

Directory of Open Access Journals (Sweden)

Melanie Ann Sacco

2009-08-01

Full Text Available Plant NB-LRR proteins confer robust protection against microbes and metazoan parasites by recognizing pathogen-derived avirulence (Avr proteins that are delivered to the host cytoplasm. Microbial Avr proteins usually function as virulence factors in compatible interactions; however, little is known about the types of metazoan proteins recognized by NB-LRR proteins and their relationship with virulence. In this report, we demonstrate that the secreted protein RBP-1 from the potato cyst nematode Globodera pallida elicits defense responses, including cell death typical of a hypersensitive response (HR, through the NB-LRR protein Gpa2. Gp-Rbp-1 variants from G. pallida populations both virulent and avirulent to Gpa2 demonstrated a high degree of polymorphism, with positive selection detected at numerous sites. All Gp-RBP-1 protein variants from an avirulent population were recognized by Gpa2, whereas virulent populations possessed Gp-RBP-1 protein variants both recognized and non-recognized by Gpa2. Recognition of Gp-RBP-1 by Gpa2 correlated to a single amino acid polymorphism at position 187 in the Gp-RBP-1 SPRY domain. Gp-RBP-1 expressed from Potato virus X elicited Gpa2-mediated defenses that required Ran GTPase-activating protein 2 (RanGAP2, a protein known to interact with the Gpa2 N terminus. Tethering RanGAP2 and Gp-RBP-1 variants via fusion proteins resulted in an enhancement of Gpa2-mediated responses. However, activation of Gpa2 was still dependent on the recognition specificity conferred by amino acid 187 and the Gpa2 LRR domain. These results suggest a two-tiered process wherein RanGAP2 mediates an initial interaction with pathogen-delivered Gp-RBP-1 proteins but where the Gpa2 LRR determines which of these interactions will be productive.

Exploration of Structural Changes in Lactose Permease on Sugar Binding and Proton Transport through Atomistic Simulations

Science.gov (United States)

Liu, Jin; Jewel, Yead; Dutta, Prashanta

2017-11-01

Escherichia coli lactose permease (LacY) actively transports lactose and other galactosides across cell membranes through lactose/H+ symport process. Lactose/H+ symport is a highly complex process that involves large-scale protein conformational changes. The complete picture of lactose/H+ symport is largely unclear. In this work, we develop the force field for sugar molecules compatible with PACE, a hybrid and coarse-grained force field that couples the united-atom protein models with the coarse-grained MARTINI water/lipid. After validation, we implement the new force field to investigate the binding of a β-D-galactopyranosyl-1-thio- β-D-galactopyranoside (TDG) molecule to a wild-type LacY. Transitions from inward-facing to outward-facing conformations upon TDG binding and protonation of Glu269 have been achieved from microsecond simulations. Both the opening of the periplasmic side and closure of the cytoplasmic side of LacY are consistent with experiments. Our analysis suggest that the conformational changes of LacY are a cumulative consequence of inter-domain H-bonds breaking at the periplasmic side, inter-domain salt-bridge formation at the cytoplasmic side, as well as the TDG orientational changes during the transition. This work is supported by US National Science Foundation under Grant No. CBET-1604211.

In silico analysis of amino acid biosynthesis and proteolysis in Lactobacillus delbrueckii subsp. bulgaricus 2038 and the implications for bovine milk fermentation.

Science.gov (United States)

Zheng, Huajun; Liu, Enuo; Hao, Pei; Konno, Tomonobu; Oda, Munehiro; Ji, Zai-Si

2012-08-01

The amino acid biosynthesis pathway and proteolytic system of Lactobacillus delbrueckii subsp. bulgaricus 2038 (L. bulgaricus 2038), a mainstay of large-scale yogurt production, were modeled based on its genomic sequence. L. bulgaricus 2038 retains more potential for amino acid synthesis and a more powerful proteolytic system than other L. bulgaricus strains, but favors amino acid uptake over de novo synthesis. Free amino acids and peptides in bovine milk provide the main nitrogen sources; whey is more important than casein for L. bulgaricus during fermentation. Free amino acids are imported by amino acid permeases and by ABC-type transport systems whereas exogenous oligopeptides are imported by ABC-type proteins only. Histidine is neither synthesized nor imported singly, which might explain why L. bulgaricus cannot grow in synthetic media.

Molecular cloning and expression of the hyu genes from Microbacterium liquefaciens AJ 3912, responsible for the conversion of 5-substituted hydantoins to alpha-amino acids, in Escherichia coli.

Science.gov (United States)

Suzuki, Shun'ichi; Takenaka, Yasuhiro; Onishi, Norimasa; Yokozeki, Kenzo

2005-08-01

A DNA fragment from Microbacterium liquefaciens AJ 3912, containing the genes responsible for the conversion of 5-substituted-hydantoins to alpha-amino acids, was cloned in Escherichia coli and sequenced. Seven open reading frames (hyuP, hyuA, hyuH, hyuC, ORF1, ORF2, and ORF3) were identified on the 7.5 kb fragment. The deduced amino acid sequence encoded by the hyuA gene included the N-terminal amino acid sequence of the hydantoin racemase from M. liquefaciens AJ 3912. The hyuA, hyuH, and hyuC genes were heterologously expressed in E. coli; their presence corresponded with the detection of hydantoin racemase, hydantoinase, and N-carbamoyl alpha-amino acid amido hydrolase enzymatic activities respectively. The deduced amino acid sequences of hyuP were similar to those of the allantoin (5-ureido-hydantoin) permease from Saccharomyces cerevisiae, suggesting that hyuP protein might function as a hydantoin transporter.

Photoluminescence of heterostructures with GaP1−xNx and GaP1−x−yNxAsy layers grown on GaP and Si substrates by molecular-beam epitaxy

International Nuclear Information System (INIS)

Lazarenko, A. A.; Nikitina, E. V.; Sobolev, M. S.; Pirogov, E. V.; Denisov, D. V.; Egorov, A. Yu.

2015-01-01

The structural and optical properties of heterostructures containing GaP 1−x N x ternary and GaP 1−x−y N x As y quaternary alloy layers are discussed. The heterostructures are grown by molecular-beam epitaxy on GaP and Si substrates. The structures are studied by the high-resolution X-ray diffraction technique and photoluminescence measurements in a wide temperature range from 10 to 300 K. In the low-temperature photoluminescence spectra of the alloys with a low nitrogen fraction (x < 0.007), two clearly resolved narrow lines attributed to the localized states of nitrogen pairs and the phonon replicas of these lines are observed

NCBI nr-aa BLAST: CBRC-CBRI-04-0044 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CBRI-04-0044 ref|NP_595047.1| malate permease [Schizosaccharomyces pombe 972h-...] ref|NP_595048.1| malate permease [Schizosaccharomyces pombe 972h-] ref|NP_595049.1| malate permease [Schizosaccharomyce...s pombe 972h-] ref|NP_595050.1| malate permease [Schizosaccharomyces pombe 972h-] emb|CAC36913....1| membrane transporter (predicted) [Schizosaccharomyces pombe] emb|CAC36914.1| m...embrane transporter (predicted) [Schizosaccharomyces pombe] emb|CAC36915.1| membrane transporter (predicted) [Schizosaccharomyce

The Arabidopsis thalianaK+-uptake permease 7 (AtKUP7) contains a functional cytosolic adenylate cyclase catalytic centre

KAUST Repository

Al-Younis, Inas

2015-11-27

Adenylate Cyclases (ACs) catalyze the formation of the second messenger cyclic adenosine 3′, 5′-monophosphate (cAMP) from adenosine 5’-triphosphate (ATP). Although cAMP is increasingly recognized as an important signaling molecule in higher plants, ACs have remained somewhat elusive. Here we used a search motif derived from experimentally tested guanylyl cyclases (GCs), substituted the residues essential for substrate specificity and identified the Arabidopsis thaliana K+-uptake permease 7 (AtKUP7) as one of several candidate ACs. Firstly, we show that a recombinant N-terminal, cytosolic domain of AtKUP71-100 is able to complement the AC-deficient mutant cyaA in Escherichia coli and thus restoring the fermentation of lactose, and secondly, we demonstrate with both enzyme immunoassays and mass spectrometry that a recombinant AtKUP71-100 generates cAMP in vitro.

The inverse F-BAR domain protein srGAP2 acts through srGAP3 to modulate neuronal differentiation and neurite outgrowth of mouse neuroblastoma cells.

Directory of Open Access Journals (Sweden)

Yue Ma

Full Text Available The inverse F-BAR (IF-BAR domain proteins srGAP1, srGAP2 and srGAP3 are implicated in neuronal development and may be linked to mental retardation, schizophrenia and seizure. A partially overlapping expression pattern and highly similar protein structures indicate a functional redundancy of srGAPs in neuronal development. Our previous study suggests that srGAP3 negatively regulates neuronal differentiation in a Rac1-dependent manner in mouse Neuro2a cells. Here we show that exogenously expressed srGAP1 and srGAP2 are sufficient to inhibit valporic acid (VPA-induced neurite initiation and growth in the mouse Neuro2a cells. While ectopic- or over-expression of RhoGAP-defective mutants, srGAP1(R542A and srGAP2(R527A exert a visible inhibitory effect on neuronal differentiation. Unexpectedly, knockdown of endogenous srGAP2 fails to facilitate the neuronal differentiation induced by VPA, but promotes neurite outgrowth of differentiated cells. All three IF-BAR domains from srGAP1-3 can induce filopodia formation in Neuro2a, but the isolated IF-BAR domain from srGAP2, not from srGAP1 and srGAP3, can promote VPA-induced neurite initiation and neuronal differentiation. We identify biochemical and functional interactions of the three srGAPs family members. We propose that srGAP3-Rac1 signaling may be required for the effect of srGAP1 and srGAP2 on attenuating neuronal differentiation. Furthermore, inhibition of Slit-Robo interaction can phenocopy a loss-of-function of srGAP3, indicating that srGAP3 may be dedicated to the Slit-Robo pathway. Our results demonstrate the interplay between srGAP1, srGAP2 and srGAP3 regulates neuronal differentiation and neurite outgrowth. These findings may provide us new insights into the possible roles of srGAPs in neuronal development and a potential mechanism for neurodevelopmental diseases.

Medicago truncatula Zinc-Iron Permease6 provides zinc to rhizobia-infected nodule cells.

Science.gov (United States)

Abreu, Isidro; Saéz, Ángela; Castro-Rodríguez, Rosario; Escudero, Viviana; Rodríguez-Haas, Benjamín; Senovilla, Marta; Larue, Camille; Grolimund, Daniel; Tejada-Jiménez, Manuel; Imperial, Juan; González-Guerrero, Manuel

2017-11-01

Zinc is a micronutrient required for symbiotic nitrogen fixation. It has been proposed that in model legume Medicago truncatula, zinc is delivered by the root vasculature into the nodule and released in the infection/differentiation zone. There, transporters must introduce this element into rhizobia-infected cells to metallate the apoproteins that use zinc as a cofactor. MtZIP6 (Medtr4g083570) is an M. truncatula Zinc-Iron Permease (ZIP) that is expressed only in roots and nodules, with the highest expression levels in the infection/differentiation zone. Immunolocalization studies indicate that it is located in the plasma membrane of nodule rhizobia-infected cells. Down-regulating MtZIP6 expression levels with RNAi does not result in any strong phenotype when plants are fed mineral nitrogen. However, these plants displayed severe growth defects when they depended on nitrogen fixed by their nodules, losing of 80% of their nitrogenase activity. The reduction of this activity was likely an indirect effect of zinc being retained in the infection/differentiation zone and not reaching the cytosol of rhizobia-infected cells. These data are consistent with a model in which MtZIP6 would be responsible for zinc uptake by rhizobia-infected nodule cells in the infection/differentiation zone. © 2017 John Wiley & Sons Ltd.

Physiological desensitization of carbohydrate permeases and adenylate cyclase to regulation by the phosphoenolpyruvate:sugar phosphotransferase system in Escherichia coli and Salmonella typhimurium. Involvement of adenosine cyclic 3',5'-phosphate and inducer.

Science.gov (United States)

Saier, M H; Keeler, D K; Feucht, B U

1982-03-10

Adenylate cyclase and a number of carbohydrate transport systems are subject to regulation by the phosphoenolpyruvate:sugar phosphotransferase system. These sensitive carbohydrate transport systems are desensitized to regulation by the phosphotransferase system, and adenylate cyclase is deactivated when cells are grown in medium containing cyclic AMP. These effects are specific for cyclic AMP and are potentiated by the genetic loss of cyclic AMP phosphodiesterase. Inclusion in the growth medium of an inducer of a sensitive transport system also promotes desensitization of that particular transport system. Inducer-promoted desensitization is specific for the particular target transport system, while cyclic AMP-promoted desensitization is general and affects several systems. Desensitization of the permeases to regulation, and inactivation of adenylate cyclase, are slow processes which are blocked by chloramphenicol and are therefore presumably dependent on protein synthesis. Several sugar substrates of the phosphotransferase system are capable of regulating the sensitive carbohydrate transport systems. The evidence suggests that desensitization to this regulation does not result from a direct effect on the functioning of Enzyme I, a small heat-stable protein of the phosphotransferase system, HPr, or an Enzyme II of the phosphotransferase system, but specifically uncouples the permease systems from regulation.

Superconducting gap symmetry in the superconductor BaFe1.9Ni0.1As2

Science.gov (United States)

Kuzmicheva, T. E.; Kuzmichev, S. A.; Sadakov, A. V.; Gavrilkin, S. Yu.; Tsvetkov, A. Yu.; Lu, X.; Luo, H.; Vasiliev, A. N.; Pudalov, V. M.; Chen, Xiao-Jia; Abdel-Hafiez, Mahmoud

2018-06-01

We report on the Andreev spectroscopy and specific heat of high-quality single crystals of BaFe1.9Ni0.1As2 . The intrinsic multiple Andreev reflection spectroscopy reveals two anisotropic superconducting gaps ΔL≈3.2 -4.5 meV , ΔS≈1.2 -1.6 meV (the ranges correspond to the minimum and maximum value of the coupling energy in the kxky plane). The 25 %-30 % anisotropy shows the absence of nodes in the superconducting gaps. Using a two-band model with s -wave-like gaps ΔL≈3.2 meV and ΔS≈1.6 meV , the temperature dependence of the electronic specific heat can be well described. A linear magnetic field dependence of the low-temperature specific heat offers further support of s -wave type of the order parameter. We find that a d -wave or single-gap BCS theory under the weak-coupling approach cannot describe our experiments.

NCBI nr-aa BLAST: CBRC-CBRI-05-0377 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CBRI-05-0377 gb|AAT81598.2| phosphate permease [Litomosoides sigmodontis] gb|A...BA63170.1| phosphate permease variant 2 [Litomosoides sigmodontis] gb|ABA63171.1| phosphate permease variant 3 [Litomosoides sigmodontis] AAT81598.2 4e-28 31% ...

The AAP gene family for amino acid permeases contributes to development of the cyst nematode Heterodera schachtii in roots of Arabidopsis.

Science.gov (United States)

Elashry, Abdelnaser; Okumoto, Sakiko; Siddique, Shahid; Koch, Wolfgang; Kreil, David P; Bohlmann, Holger

2013-09-01

The beet cyst nematode Heterodera schachtii is able to infect Arabidopsis plants and induce feeding sites in the root. These syncytia are the only source of nutrients for the nematodes throughout their life and are a nutrient sink for the host plant. We have studied here the role of amino acid transporters for nematode development. Arabidopsis contains a large number of different amino acid transporters in several gene families but those of the AAP family were found to be especially expressed in syncytia. Arabidopsis contains 8 AAP genes and they were all strongly expressed in syncytia with the exception of AAP5 and AAP7, which were slightly downregulated. We used promoter::GUS lines and in situ RT-PCR to confirm the expression of several AAP genes and LHT1, a lysine- and histidine-specific amino acid transporter, in syncytia. The strong expression of AAP genes in syncytia indicated that these transporters are important for the transport of amino acids into syncytia and we used T-DNA mutants for several AAP genes to test for their influence on nematode development. We found that mutants of AAP1, AAP2, and AAP8 significantly reduced the number of female nematodes developing on these plants. Our study showed that amino acid transport into syncytia is important for the development of the nematodes. Copyright © 2013 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

A constitutive pan-hexose permease for the Plasmodium life cycle and transgenic models for screening of antimalarial sugar analogs.

Science.gov (United States)

Blume, Martin; Hliscs, Marion; Rodriguez-Contreras, Dayana; Sanchez, Marco; Landfear, Scott; Lucius, Richard; Matuschewski, Kai; Gupta, Nishith

2011-04-01

Glucose is considered essential for erythrocytic stages of the malaria parasite, Plasmodium falciparum. Importance of sugar and its permease for hepatic and sexual stages of Plasmodium, however, remains elusive. Moreover, increasing global resistance to current antimalarials necessitates the search for novel drugs. Here, we reveal that hexose transporter 1 (HT1) of Plasmodium berghei can transport glucose (K(m)~87 μM), mannose (K(i)~93 μM), fructose (K(i)~0.54 mM), and galactose (K(i)~5 mM) in Leishmania mexicana mutant and Xenopus laevis; and, therefore, is functionally equivalent to HT1 of P. falciparum (Glc, K(m)~175 μM; Man, K(i)~276 μM; Fru, K(i)~1.25 mM; Gal, K(i)~5.86 mM). Notably, a glucose analog, C3361, attenuated hepatic (IC(50)~15 μM) and ookinete development of P. berghei. The PbHT1 could be ablated during intraerythrocytic stages only by concurrent complementation with PbHT1-HA or PfHT1. Together; these results signify that PbHT1 and glucose are required for the entire life cycle of P. berghei. Accordingly, PbHT1 is expressed in the plasma membrane during all parasite stages. To permit a high-throughput screening of PfHT1 inhibitors and their subsequent in vivo assessment, we have generated Saccharomyces cerevisiae mutant expressing codon-optimized PfHT1, and a PfHT1-dependent Δpbht1 parasite strain. This work provides a platform to facilitate the development of drugs against malaria, and it suggests a disease-control aspect by reducing parasite transmission.

The Serum Anion Gap in the Evaluation of Acid-Base Disorders: What Are Its Limitations and Can Its Effectiveness Be Improved?

OpenAIRE

Kraut, Jeffrey A.; Nagami, Glenn T.

2013-01-01

The serum anion gap has been utilized to identify errors in the measurement of electrolytes, to detect paraproteins, and, most relevant to the nephrologist, to evaluate patients with suspected acid-base disorders. In regard to the latter purpose, traditionally an increased anion gap is identified when it exceeds the upper limit of normal for a particular clinical laboratory measurement. However, because there is a wide range of normal values (often 8–10 mEq/L), an increase in anion concentrat...

The F-BAR domains from srGAP1, srGAP2 and srGAP3 regulate membrane deformation differently

Science.gov (United States)

Coutinho-Budd, Jaeda; Ghukasyan, Vladimir; Zylka, Mark J.; Polleux, Franck

2012-01-01

Summary Coordination of membrane deformation and cytoskeletal dynamics lies at the heart of many biological processes critical for cell polarity, motility and morphogenesis. We have recently shown that Slit-Robo GTPase-activating protein 2 (srGAP2) regulates neuronal morphogenesis through the ability of its F-BAR domain to regulate membrane deformation and induce filopodia formation. Here, we demonstrate that the F-BAR domains of two closely related family members, srGAP1 and srGAP3 [designated F-BAR(1) and F-BAR(3), respectively] display significantly different membrane deformation properties in non-neuronal COS7 cells and in cortical neurons. F-BAR(3) induces filopodia in both cell types, though less potently than F-BAR(2), whereas F-BAR(1) prevents filopodia formation in cortical neurons and reduces plasma membrane dynamics. These three F-BAR domains can heterodimerize, and they act synergistically towards filopodia induction in COS7 cells. As measured by fluorescence recovery after photobleaching, F-BAR(2) displays faster molecular dynamics than F-BAR(3) and F-BAR(1) at the plasma membrane, which correlates well with its increased potency to induce filopodia. We also show that the molecular dynamic properties of F-BAR(2) at the membrane are partially dependent on F-Actin. Interestingly, acute phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] depletion in cells does not interfere with plasma membrane localization of F-BAR(2), which is compatible with our result showing that F-BAR(2) binds to a broad range of negatively-charged phospholipids present at the plasma membrane, including phosphatidylserine (PtdSer). Overall, our results provide novel insights into the functional diversity of the membrane deformation properties of this subclass of F-BAR-domains required for cell morphogenesis. PMID:22467852

Mel-18 interacts with RanGAP1 and inhibits its sumoylation.

Science.gov (United States)

Zhang, Jie; Sarge, Kevin D

2008-10-17

Our previous results showed that the polycomb protein mel-18 binds to a protein called HSF2 and inhibits HSF2 sumoylation, thereby functioning as an anti-SUMO E3 factor. This study also suggested that mel-18 regulates the sumoylation of other cellular proteins, but the identities of these other proteins were unknown. Here we show that mel-18 interacts with the RanGAP1 protein and inhibits its sumoylation, and that these activities do not require the RING domain of mel-18. The results also show that RanGAP1 sumoylation is decreased during mitosis, and that this is associated with increased interaction between RanGAP1 and mel-18 during this stage of the cell cycle. Intriguingly, this regulatory relationship is the opposite of that found for mel-18 and HSF2, in which the interaction between these two proteins decreases during mitosis, resulting in elevated HSF2 sumoylation. The results of this study strengthen the conclusion that mel-18 functions as an anti-SUMO E3 factor, and extend its targets to include regulation of the sumoylation of the important cellular protein RanGAP1.

Ginsenoside Rg1 alleviates corticosterone-induced dysfunction of gap junctions in astrocytes.

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Xia, Cong-Yuan; Chu, Shi-Feng; Zhang, Shuai; Gao, Yan; Ren, Qian; Lou, Yu-Xia; Luo, Piao; Tian, Man-Tong; Wang, Zhi-Qi; Du, Guo-Hua; Tomioka, Yoshihisa; Yamakuni, Tohru; Zhang, Yi; Wang, Zhen-Zhen; Chen, Nai-Hong

2017-08-17

Ginsenoside Rg1 (Rg1), one of the major bioactive ingredients of Panax ginseng C. A. Mey, has neuroprotective effects in animal models of depression, but the mechanism underlying these effects is still largely unknown AIM OF THE STUDY: Gap junction intercellular communication (GJIC) dysfunction is a potentially novel pathogenic mechanism for depression. Thus, we investigated that whether antidepressant-like effects of Rg1 were related to GJIC. Primary rat prefrontal cortical and hippocampal astrocytes cultures were treated with 50μM CORT for 24h to induce gap junction damage. Rg1 (0.1, 1, or 10μM) or fluoxetine (1μM) was added 1h prior to CORT treatment. A scrape loading and dye transfer assay was performed to identify the functional capacity of gap junctions. Western blot was used to detect the expression and phosphorylation of connexin43 (Cx43), the major component of gap junctions. Treatment of primary astrocytes with CORT for 24h inhibited GJIC, decreased total Cx43 expression, and increased the phosphorylation of Cx43 at serine368 in a dose-dependent manner. Pre-treatment with 1μM and 10μM Rg1 significantly improved GJIC in CORT-treated astrocytes from the prefrontal cortex and hippocampus, respectively, and this was accompanied by upregulation of Cx43 expression and downregulation of Cx43 phosphorylation. These findings provide the first evidence indicating that Rg1 can alleviate CORT-induced gap junction dysfunction, which may have clinical significance in the treatment of depression. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Investigation of nutrient sensing in the yeast Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Eckert-Boulet, Nadine

2006-01-01

medfører transkriptionel induktion. For at kunne bekræfte eller identificere nye gener som reguleres via SPS-systemet, blev der udført global transkriptionel profilering af vildtype stammer samt af stammer deleterede for enten SSY1 eller STP1 og STP2, både med og uden aminosyren L-citrullin i mediet. L......-citrulline kan ikke optages af disse stammer, da de mangler GAP1 (General Amino acid Permease). Det blev bekræftet, at AAP generne TAT1, BAP2, BAP3 og PTR2 er under kontrol af aminosyre induktionsvejen, mens AGP2 blev identificeret som et nyt gen under kontrol af denne mekanisme. Den globale...... transkriptionsanalyse viste at 46 gener induceres af L-citrullin, afhængigt af Ssy1p og Stp1p/Stp2p. Sekvenssammenligning af promoterregionerne muliggjorde en mere præcis definition af den tidligere beskrevet Upstream Activating Sequence (UASaa). Udover effekten på AAP gener, viste ssy1 og stp1 stp2 mutanter mange...

Exploration of conformational changes in lactose permease upon sugar binding and proton transfer through coarse-grained simulations.

Science.gov (United States)

Jewel, Yead; Dutta, Prashanta; Liu, Jin

2017-10-01

Escherichia coli lactose permease (LacY) actively transports lactose and other galactosides across cell membranes through lactose/H + symport process. Lactose/H + symport is a highly complex process that involves sugar translocation, H + transfer, and large-scale protein conformational changes. The complete picture of lactose/H + symport is largely unclear due to the complexity and multiscale nature of the process. In this work, we develop the force field for sugar molecules compatible with PACE, a hybrid and coarse-grained force field that couples the united-atom protein models with the coarse-grained MARTINI water/lipid. After validation, we implement the new force field to investigate the binding of a β-d-galactopyranosyl-1-thio- β-d-galactopyranoside (TDG) molecule to a wild-type LacY. Results show that the local interactions between TDG and LacY at the binding pocket are consistent with the X-ray experiment. Transitions from inward-facing to outward-facing conformations upon TDG binding and protonation of Glu269 have been achieved from ∼5.5 µs simulations. Both the opening of the periplasmic side and closure of the cytoplasmic side of LacY are consistent with double electron-electron resonance and thiol cross-linking experiments. Our analysis suggests that the conformational changes of LacY are a cumulative consequence of interdomain H-bonds breaking at the periplasmic side, interdomain salt-bridge formation at the cytoplasmic side, and the TDG orientational changes during the transition. © 2017 Wiley Periodicals, Inc.

Involvement of the ornithine decarboxylase gene in acid stress response in probiotic Lactobacillus delbrueckii UFV H2b20.

Science.gov (United States)

Ferreira, A B; Oliveira, M N V de; Freitas, F S; Paiva, A D; Alfenas-Zerbini, P; Silva, D F da; Queiroz, M V de; Borges, A C; Moraes, C A de

2015-01-01

Amino acid decarboxylation is important for the maintenance of intracellular pH under acid stress. This study aims to carry out phylogenetic and expression analysis by real-time PCR of two genes that encode proteins involved in ornithine decarboxylation in Lactobacillus delbrueckii UFV H2b20 exposed to acid stress. Sequencing and phylogeny analysis of genes encoding ornithine decarboxylase and amino acid permease in L. delbrueckii UFV H2b20 showed their high sequence identity (99%) and grouping with those of L. delbrueckii subsp. bulgaricus ATCC 11842. Exposure of L. delbrueckii UFV H2b20 cells in MRS pH 3.5 for 30 and 60 min caused a significant increase in expression of the gene encoding ornithine decarboxylase (up to 8.1 times higher when compared to the control treatment). Increased expression of the ornithine decarboxylase gene demonstrates its involvement in acid stress response in L. delbrueckii UFV H2b20, evidencing that the protein encoded by that gene could be involved in intracellular pH regulation. The results obtained show ornithine decarboxylation as a possible mechanism of adaptation to an acidic environmental condition, a desirable and necessary characteristic for probiotic cultures and certainly important to the survival and persistence of the L. delbrueckii UFV H2b20 in the human gastrointestinal tract.

A comparison of prognostic significance of strong ion gap (SIG) with other acid-base markers in the critically ill: a cohort study.

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Ho, Kwok M; Lan, Norris S H; Williams, Teresa A; Harahsheh, Yusra; Chapman, Andrew R; Dobb, Geoffrey J; Magder, Sheldon

2016-01-01

This cohort study compared the prognostic significance of strong ion gap (SIG) with other acid-base markers in the critically ill. The relationships between SIG, lactate, anion gap (AG), anion gap albumin-corrected (AG-corrected), base excess or strong ion difference-effective (SIDe), all obtained within the first hour of intensive care unit (ICU) admission, and the hospital mortality of 6878 patients were analysed. The prognostic significance of each acid-base marker, both alone and in combination with the Admission Mortality Prediction Model (MPM0 III) predicted mortality, were assessed by the area under the receiver operating characteristic curve (AUROC). Of the 6878 patients included in the study, 924 patients (13.4 %) died after ICU admission. Except for plasma chloride concentrations, all acid-base markers were significantly different between the survivors and non-survivors. SIG (with lactate: AUROC 0.631, confidence interval [CI] 0.611-0.652; without lactate: AUROC 0.521, 95 % CI 0.500-0.542) only had a modest ability to predict hospital mortality, and this was no better than using lactate concentration alone (AUROC 0.701, 95 % 0.682-0.721). Adding AG-corrected or SIG to a combination of lactate and MPM0 III predicted risks also did not substantially improve the latter's ability to differentiate between survivors and non-survivors. Arterial lactate concentrations explained about 11 % of the variability in the observed mortality, and it was more important than SIG (0.6 %) and SIDe (0.9 %) in predicting hospital mortality after adjusting for MPM0 III predicted risks. Lactate remained as the strongest predictor for mortality in a sensitivity multivariate analysis, allowing for non-linearity of all acid-base markers. The prognostic significance of SIG was modest and inferior to arterial lactate concentration for the critically ill. Lactate concentration should always be considered regardless whether physiological, base excess or physical-chemical approach

Anomalous band-gap bowing of AlN1−xPx alloy

International Nuclear Information System (INIS)

Winiarski, M.J.; Polak, M.; Scharoch, P.

2013-01-01

Highlights: •Structural and electronic properties of AlN 1−x P x from first principles. •The supercell and the virtual crystall approximation methods applied and compared. •Anomalously high band-gap bowing found. •Similarities of band-gap behavior to that in BN 1−x P x noticed. •Performance of MBJLDA with the pseudopotential approach discussed. -- Abstract: Electronic structure of zinc blende AlN 1−x P x alloy has been calculated from first principles. Structural optimization has been performed within the framework of LDA and the band-gaps calculated with the modified Becke–Jonson (MBJLDA) method. Two approaches have been examined: the virtual crystal approximation (VCA) and the supercell-based calculations (SC). The composition dependence of the lattice parameter obtained from the SC obeys Vegard’s law whereas the volume optimization in the VCA leads to an anomalous bowing of the lattice constant. A strong correlation between the band-gaps and the structural parameter in the VCA method has been observed. On the other hand, in the SC method the supercell size and atoms arrangement (clustered vs. uniform) appear to have a great influence on the computed band-gaps. In particular, an anomalously big band-gap bowing has been found in the case of a clustered configuration with relaxed geometry. Based on the performed tests and obtained results some general features of MBJLDA are discussed and its performance for similar systems predicted

The role of glyceraldehyde 3-phosphate dehydrogenase (GapA-1 in Neisseria meningitidis adherence to human cells

Directory of Open Access Journals (Sweden)

Wooldridge Karl G

2010-11-01

Full Text Available Abstract Background Glyceraldehyde 3-phosphate dehydrogenases (GAPDHs are cytoplasmic glycolytic enzymes, which although lacking identifiable secretion signals, have also been found localized to the surface of several bacteria (and some eukaryotic organisms; where in some cases they have been shown to contribute to the colonization and invasion of host tissues. Neisseria meningitidis is an obligate human nasopharyngeal commensal which can cause life-threatening infections including septicaemia and meningitis. N. meningitidis has two genes, gapA-1 and gapA-2, encoding GAPDH enzymes. GapA-1 has previously been shown to be up-regulated on bacterial contact with host epithelial cells and is accessible to antibodies on the surface of capsule-permeabilized meningococcal cells. The aims of this study were: 1 to determine whether GapA-1 was expressed across different strains of N. meningitidis; 2 to determine whether GapA-1 surface accessibility to antibodies was dependant on the presence of capsule; 3 to determine whether GapA-1 can influence the interaction of meningococci and host cells, particularly in the key stages of adhesion and invasion. Results In this study, expression of GapA-1 was shown to be well conserved across diverse isolates of Neisseria species. Flow cytometry confirmed that GapA-1 could be detected on the cell surface, but only in a siaD-knockout (capsule-deficient background, suggesting that GapA-1 is inaccessible to antibody in in vitro-grown encapsulated meningococci. The role of GapA-1 in meningococcal pathogenesis was addressed by mutational analysis and functional complementation. Loss of GapA-1 did not affect the growth of the bacterium in vitro. However, a GapA-1 deficient mutant showed a significant reduction in adhesion to human epithelial and endothelial cells compared to the wild-type and complemented mutant. A similar reduction in adhesion levels was also apparent between a siaD-deficient meningococcal strain and an

NCBI nr-aa BLAST: CBRC-LAFR-01-2596 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-LAFR-01-2596 ref|YP_676997.1| possible permease [Cytophaga hutchinsonii ATCC 3...3406] gb|ABG57657.1| possible permease [Cytophaga hutchinsonii ATCC 33406] YP_676997.1 0.14 30% ...

Improvement of pea biomass and seed productivity by simultaneous increase of phloem and embryo loading with amino acids.

Science.gov (United States)

Zhang, Lizhi; Garneau, Matthew G; Majumdar, Rajtilak; Grant, Jan; Tegeder, Mechthild

2015-01-01

The development of sink organs such as fruits and seeds strongly depends on the amount of nitrogen that is moved within the phloem from photosynthetic-active source leaves to the reproductive sinks. In many plant species nitrogen is transported as amino acids. In pea (Pisum sativum L.), source to sink partitioning of amino acids requires at least two active transport events mediated by plasma membrane-localized proteins, and these are: (i) amino acid phloem loading; and (ii) import of amino acids into the seed cotyledons via epidermal transfer cells. As each of these transport steps might potentially be limiting to efficient nitrogen delivery to the pea embryo, we manipulated both simultaneously. Additional copies of the pea amino acid permease PsAAP1 were introduced into the pea genome and expression of the transporter was targeted to the sieve element-companion cell complexes of the leaf phloem and to the epidermis of the seed cotyledons. The transgenic pea plants showed increased phloem loading and embryo loading of amino acids resulting in improved long distance transport of nitrogen, sink development and seed protein accumulation. Analyses of root and leaf tissues further revealed that genetic manipulation positively affected root nitrogen uptake, as well as primary source and sink metabolism. Overall, the results suggest that amino acid phloem loading exerts regulatory control over pea biomass production and seed yield, and that import of amino acids into the cotyledons limits seed protein levels. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

NCBI nr-aa BLAST: CBRC-CREM-01-1290 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CREM-01-1290 ref|YP_001478049.1| uracil-xanthine permease [Serratia proteamacu...lans 568] gb|ABV40921.1| uracil-xanthine permease [Serratia proteamaculans 568] YP_001478049.1 3e-95 65% ...

NCBI nr-aa BLAST: CBRC-TBEL-01-2529 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-TBEL-01-2529 ref|YP_001162719.1| 4-hydroxyphenylacetate permease [Yersinia pestis Pest...oides F] gb|ABP39746.1| 4-hydroxyphenylacetate permease [Yersinia pestis Pestoides F] YP_001162719.1 0.21 30% ...

NCBI nr-aa BLAST: CBRC-OPRI-01-0183 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-OPRI-01-0183 ref|YP_002962013.1| ABC family transporter permease protein [Methylobacterium extorque...ns AM1] gb|ACS38736.1| ABC family transporter permease protein [Methylobacterium extorquens AM1] YP_002962013.1 3.3 27% ...

NCBI nr-aa BLAST: CBRC-LAFR-01-0233 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-LAFR-01-0233 ref|ZP_01459279.1| ABC transporter, permease protein [Stigmatella... aurantiaca DW4/3-1] gb|EAU69855.1| ABC transporter, permease protein [Stigmatella aurantiaca DW4/3-1] ZP_01459279.1 0.98 29% ...

NCBI nr-aa BLAST: CBRC-LAFR-01-1419 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-LAFR-01-1419 ref|ZP_01459279.1| ABC transporter, permease protein [Stigmatella... aurantiaca DW4/3-1] gb|EAU69855.1| ABC transporter, permease protein [Stigmatella aurantiaca DW4/3-1] ZP_01459279.1 0.061 29% ...

NCBI nr-aa BLAST: CBRC-LAFR-01-1856 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-LAFR-01-1856 ref|ZP_01459279.1| ABC transporter, permease protein [Stigmatella... aurantiaca DW4/3-1] gb|EAU69855.1| ABC transporter, permease protein [Stigmatella aurantiaca DW4/3-1] ZP_01459279.1 0.33 29% ...

NCBI nr-aa BLAST: CBRC-TTRU-01-0583 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-TTRU-01-0583 ref|ZP_04742692.1| ABC transporter, permease protein [Roseburia i...ntestinalis L1-82] gb|EEV02164.1| ABC transporter, permease protein [Roseburia intestinalis L1-82] ZP_04742692.1 0.17 28% ...

GAP1, a novel selection and counter-selection marker for multiple gene disruptions in Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Regenberg, Birgitte; Hansen, J.

2000-01-01

the GAP1 gene. This is caused by recombination between two Salmonella typuimurium hisG direct repeats embracing GAP1, and will result in a sub-population of gap1 cells. Such cells are selected on a medium containing D-histidine, and may subsequently be used for a second gene disruption. Hence, multiple...... flanked by short (60 bp) stretches of the gene in question. Through homologous recombination, the cassette will integrate into the target gene, which is thus replaced by GAP1, and mutants are selected for on minimal L-citrulline medium. When propagated under non-selective conditions, some cells will lose...... gene disruptions can be made fast, cheaply and easily in a gap1 strain, with two positive selection steps for each disruption. Copyright (C) 2000 John Wiley & Sons, Ltd....

Molecular characterization of a novel RhoGAP, RRC-1 of the nematode Caenorhabditis elegans

International Nuclear Information System (INIS)

Delawary, Mina; Nakazawa, Takanobu; Tezuka, Tohru; Sawa, Mariko; Iino, Yuichi; Takenawa, Tadaomi; Yamamoto, Tadashi

2007-01-01

The GTPase-activating proteins for Rho family GTPases (RhoGAP) transduce diverse intracellular signals by negatively regulating Rho family GTPase-mediated pathways. In this study, we have cloned and characterized a novel RhoGAP for Rac1 and Cdc42, termed RRC-1, from Caenorhabditis elegans. RRC-1 was highly homologous to mammalian p250GAP and promoted GTP hydrolysis of Rac1 and Cdc42 in cells. The rrc-1 mRNA was expressed in all life stages. Using an RRC-1::GFP fusion protein, we found that RRC-1 was localized to the coelomocytes, excretory cell, GLR cells, and uterine-seam cell in adult worms. These data contribute toward understanding the roles of Rho family GTPases in C. elegans

NCBI nr-aa BLAST: CBRC-SARA-01-0488 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-SARA-01-0488 ref|YP_064024.1| sulfate permease (SulP) [Desulfotalea psychrophi...la LSv54] emb|CAG35017.1| probable sulfate permease (SulP) [Desulfotalea psychrophila LSv54] YP_064024.1 6.1 37% ...

NCBI nr-aa BLAST: CBRC-XTRO-01-0450 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-XTRO-01-0450 ref|YP_001099288.1| putative sulfate permease (SulP family) [Herminiimonas arsenico...xydans] emb|CAL61161.1| putative sulfate permease (SulP family) [Herminiimonas arsenicoxydans] YP_001099288.1 1e-103 51% ...

Mapping of the minimal inorganic phosphate transporting unit of human PiT2 suggests a structure universal to PiT-related proteins from all kingdoms of life

DEFF Research Database (Denmark)

Bøttger, Pernille; Pedersen, Lene

2011-01-01

-keeping functions. Alignment of protein sequences representing PiT family members from all kingdoms reveals the presence of conserved amino acids and that bacterial phosphate permeases and putative phosphate permeases from archaea lack substantial parts of the protein sequence when compared to the mammalian Pi...... PiT2 histidine, H502, and the human PiT1 glutamate, E70, - both conserved in eukaryotic PiT family members - are critical for Pi transport function. Noticeably, human PiT2 H502 is located in the C-terminal PiT family signature sequence, and human PiT1 E70 is located in ProDom domains characteristic....... Conclusions The results suggest that the overall structure of the Pi-transporting unit of the PiT family proteins has remained unchanged during evolution. Moreover, in combination, our studies of the gene structure of the human PiT1 and PiT2 genes (SLC20A1 and SLC20A2, respectively) and alignment of protein...

NCBI nr-aa BLAST: CBRC-PABE-24-0030 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-PABE-24-0030 ref|YP_927793.1| uracil-xanthine permease [Shewanella amazonensis... SB2B] gb|ABM00124.1| uracil-xanthine permease [Shewanella amazonensis SB2B] YP_927793.1 3.4 27% ...

Theophylline–gentisic acid (1/1

Directory of Open Access Journals (Sweden)

Srinivasulu Aitipamula

2009-09-01

Full Text Available In the title 1:1 cocrystal, C7H8N4O2·C7H6O4, the anti-asthmatic drug theophylline (systematic name: 1,3-dimethyl-7H-purine-2,6-dione and a non-steroidal anti-inflammatory drug, gentisic acid (systematic name: 2,5-dihydroxybenzoic acid crystallize together, forming two-dimensional hydrogen-bonded sheets involving N—H...O and O—H...N hydrogen bonds. The overall crystal packing features π–π stacking interactions [centroid–centroid distance = 3.348 (1 Å]. The cocrystal described herein belongs to the class of pharmaceutical cocrystals involving two active pharmaceutical ingredients which has been relatively unexplored to date.

Ethane-1,1,2-trisphosphonic acid hemihydrate.

Science.gov (United States)

Delain-Bioton, Lise; Lohier, Jean François; Villemin, Didier; Sopková-de Oliveira Santos, Jana; Hix, Gary; Jaffrès, Paul Alain

2008-02-01

Ethane-1,1,2-trisphosphonic acid crystallizes as a hemihydrate, C(2)H(9)O(9)P(3).0.5H(2)O, in which the water O atom lies on an inversion centre in the space group P2(1)/c. The acid component, which contains a short but noncentred O-H...O hydrogen bond, adopts a gauche conformation. The acid components are linked by an extensive series of O-H...O hydrogen bonds to form layers, which are linked into pairs by the water molecules.

NCBI nr-aa BLAST: CBRC-MMUR-01-1348 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-MMUR-01-1348 ref|YP_003196911.1| transport system permease protein [Desulfohalobium retba...ense DSM 5692] gb|ACV67333.1| transport system permease protein [Desulfohalobium retbaense DSM 5692] YP_003196911.1 0.002 30% ...

NCBI nr-aa BLAST: CBRC-CINT-01-0058 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CINT-01-0058 ref|ZP_01183563.1| transport system permease protein [Bacillus weihenstep...hanensis KBAB4] gb|EAR76999.1| transport system permease protein [Bacillus weihenstephanensis KBAB4] ZP_01183563.1 2.4 23% ...

Postirradiation examination data report for gap conductance test series. Test GC 2-1

International Nuclear Information System (INIS)

Murdock, B.A.

1978-02-01

The results of the postirradiation examination of four boiling water reactor type, zircaloy-clad, UO 2 -fueled rods tested in the Power Burst Facility are discussed. These rods were employed in Gap Conductance Test GC 2-1 which was performed to obtain experimental data from which test fuel rod gap conductance values could be determined by both the steady state ∫kdT and the power oscillation methods. The postirradiation examination results provided in the document will aid in interpreting the experimental data obtained during Test GC 2-1 and in evaluating the effect of fuel behavior on the fuel rod thermal response and interpreted gap conductances. Fuel rod fill gas composition and pressure are discussed. Measurements of fuel pellet-cladding gap and fuel crack areas are presented. The fuel structure is analyzed. Test rod instrumentation and power profiles are examined to better evaluate the test conditions

NCBI nr-aa BLAST: CBRC-DNOV-01-2378 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DNOV-01-2378 ref|NP_325931.1| MULTIPLE SUGAR ABC TRANSPORTER PERMEASE PROTEIN ...[Mycoplasma pulmonis UAB CTIP] emb|CAC13273.1| MULTIPLE SUGAR ABC TRANSPORTER PERMEASE PROTEIN [Mycoplasma pulmonis] NP_325931.1 0.090 22% ...

NCBI nr-aa BLAST: CBRC-XTRO-01-0279 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-XTRO-01-0279 ref|ZP_01441822.1| polyamine ABC transporter (permease) [Roseovar...ius sp. HTCC2601] gb|EAU47986.1| polyamine ABC transporter (permease) [Roseovarius sp. HTCC2601] ZP_01441822.1 8e-39 36% ...

NCBI nr-aa BLAST: CBRC-TTRU-01-0889 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-TTRU-01-0889 ref|ZP_04743451.1| iron compound ABC transporter, permease protein [Roseburi...a intestinalis L1-82] gb|EEV01396.1| iron compound ABC transporter, permease protein [Roseburia intestinalis L1-82] ZP_04743451.1 0.10 26% ...

NCBI nr-aa BLAST: CBRC-OPRI-01-0183 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-OPRI-01-0183 ref|YP_003067109.1| ABC family transporter permease protein [Methylobacterium extorque...ns DM4] emb|CAX23124.1| ABC family transporter permease protein [Methylobacterium extorquens DM4] YP_003067109.1 3.3 27% ...

NCBI nr-aa BLAST: CBRC-DSIM-08-0043 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DSIM-08-0043 ref|NP_540905.1| PHOSPHATE TRANSPORT SYSTEM PERMEASE PROTEIN PSTC... [Brucella melitensis 16M] gb|AAL53169.1| PHOSPHATE TRANSPORT SYSTEM PERMEASE PROTEIN PSTC [Brucella melitensis 16M] NP_540905.1 7.9 35% ...

NCBI nr-aa BLAST: CBRC-ACAR-01-0595 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-ACAR-01-0595 ref|YP_246431.1| Zinc/manganese ABC transporter permease protein ...[Rickettsia felis URRWXCal2] gb|AAY61266.1| Zinc/manganese ABC transporter permease protein [Rickettsia felis URRWXCal2] YP_246431.1 2.0 21% ...

[Inhibition of gap junctional intercellular communication protects astrocytes from hypoxia/reoxygenation injury].

Science.gov (United States)

Tong, Xu-Hui; Gu, Yu-Chen; Jiao, Hao; Yu, Li; Dong, Shu-Ying

2015-01-01

To investigate the effects of inhibiting gap junctional intercellular communication on hypoxia/reoxygenation injury in astrocytes. Primary cultured cerebral cortical astrocytes of neonate rats were divided into normal control group, hypoxia reoxygenation injury group and 18-α-glycyrrhetinic acid and oleamide (gap junctional intercellular channel inhibitors) group. The gap junction intercellular communication was determined by Parachute assay. The viability of astrocyes was detected by MTT assay. The apoptosis of astrocytes were detected with annexin V/PI and Hoechst 33258 staining. Compared with the normal control group, the gap junctional function of astrocytes was increased significantly in ischemia/reperfusion group (Pastrocytes decreased significantly (Pastrocytes in18-α-glycyrrhetinic acid and oleamide group decreased significantly (Pastrocytes increased significantly (Pastrocytes.

NCBI nr-aa BLAST: CBRC-MDOM-02-0387 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-MDOM-02-0387 ref|YP_002730825.1| oligopeptide transport system permease protein AppB [Persephone...lla marina EX-H1] gb|ACO04361.1| oligopeptide transport system permease protein AppB [Persephonella marina EX-H1] YP_002730825.1 0.47 27% ...

NCBI nr-aa BLAST: CBRC-TTRU-01-0103 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-TTRU-01-0103 ref|YP_763917.1| HAAAP family serine permease [Francisella tulare...nsis subsp. holarctica OSU18] gb|ABI83280.1| HAAAP family serine permease [Francisella tularensis subsp. holarctica OSU18] YP_763917.1 0.077 25% ...

NCBI nr-aa BLAST: CBRC-CINT-01-0088 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CINT-01-0088 ref|ZP_00997731.1| ABC transporter, ATP binding/permease protein [Oceanicola bats...ensis HTCC2597] gb|EAQ04798.1| ABC transporter, ATP binding/permease protein [Oceanicola batsensis HTCC2597] ZP_00997731.1 0.040 24% ...

Nature of the fundamental band gap in GaNxP1-x alloys

International Nuclear Information System (INIS)

Shan, W.; Walukiewicz, W.; Yu, K. M.; Wu, J.; Ager, J. W. III; Haller, E. E.; Xin, H. P.; Tu, C. W.

2000-01-01

The optical properties of GaN x P 1-x alloys (0.007≤x≤0.031) grown by gas-source molecular-beam epitaxy have been studied. An absorption edge appears in GaN x P 1-x at energy below the indirect Γ V -X C transition in GaP, and the absorption edge shifts to lower energy with increasing N concentration. Strong photomodulation signals associated with the absorption edges in GaN x P 1-x indicate that a direct fundamental optical transition is taking place, revealing that the fundamental band gap has changed from indirect to direct. This N-induced transformation from indirect to direct band gap is explained in terms of an interaction between the highly localized nitrogen states and the extended states at the Γ conduction-band minimum. (c) 2000 American Institute of Physics

Radiation defects in GaP and solid solution of GaAssub(1-x)Psub(x)

International Nuclear Information System (INIS)

Brailovsky, E.Y.; Grigoryan, N.E.; Marchouk, N.D.; Pambuhchyan, N.H.; Tartachnik, V.P.

1979-01-01

The introduction and annealing behaviour of radiation defects in GaP and GaAssub(1-x)Psub(x) at 1 to 50 MeV electron irradiation was investigated by the Hall effect, thermal stimulated current (TSC) and optical absorption. The recovery of electrical properties of irradiated GaAssub(1-x)Psub(x) was dependent on x. From TSC measurement it has been shown that the predominant radiation defects in GaP are electron traps Esub(c) - (1.2 +- 0.1)eV and hole traps Esub(v) + (1.5 +- 0.15)eV which are the cause of n and p decreasing in GaP crystals. The formation of density state 'tails' during irradiation was investigated. (author)

Modification in band gap of zirconium complexes

Energy Technology Data Exchange (ETDEWEB)

Sharma, Mayank, E-mail: mayank30134@gmail.com; Singh, J.; Chouhan, S. [Department of Physics, ISLE, IPS Academy, Indore (M.P.) (India); Mishra, A. [School of Physics, Devi Ahilya Vishwavidyalaya, Indore (M.P.) (India); Shrivastava, B. D. [Govt. P. G. College, Biora (M.P.) (India)

2016-05-06

The optical properties of zirconium complexes with amino acid based Schiff bases are reported here. The zirconium complexes show interesting stereo chemical features, which are applicable in organometallic and organic synthesis as well as in catalysis. The band gaps of both Schiff bases and zirconium complexes were obtained by UV-Visible spectroscopy. It was found that the band gap of zirconium complexes has been modified after adding zirconium compound to the Schiff bases.

A Gap in Time: Extending our Knowledge of Temporal Processing Deficits in the HIV-1 Transgenic Rat.

Science.gov (United States)

McLaurin, Kristen A; Moran, Landhing M; Li, Hailong; Booze, Rosemarie M; Mactutus, Charles F

2017-03-01

Approximately 50 % of HIV-1 seropositive individuals develop HIV-1 associated neurocognitive disorders (HAND), which commonly include alterations in executive functions, such as inhibition, set shifting, and complex problem solving. Executive function deficits in HIV-1 are fairly well characterized, however, relatively few studies have explored the elemental dimensions of neurocognitive impairment in HIV-1. Deficits in temporal processing, caused by HIV-1, may underlie the symptoms of impairment in higher level cognitive processes. Translational measures of temporal processing, including cross-modal prepulse inhibition (PPI), gap-prepulse inhibition (gap-PPI), and gap threshold detection, were studied in mature (ovariectomized) female HIV-1 transgenic (Tg) rats, which express 7 of the 9 HIV-1 genes constitutively throughout development. Cross-modal PPI revealed a relative insensitivity to the manipulation of interstimulus interval (ISI) in HIV-1 Tg animals in comparison to control animals, extending previously reported temporal processing deficits in HIV-1 Tg rats to a more advanced age, suggesting the permanence of temporal processing deficits. In gap-PPI, HIV-1 Tg animals exhibited a relative insensitivity to the manipulation of ISI in comparison to control animals. In gap-threshold detection, HIV-1 Tg animals displayed a profound differential sensitivity to the manipulation of gap duration. Presence of the HIV-1 transgene was diagnosed with 91.1 % accuracy using gap threshold detection measures. Understanding the generality and permanence of temporal processing deficits in the HIV-1 Tg rat is vital to modeling neurocognitive deficits observed in HAND and provides a key target for the development of a diagnostic screening tool.

NCBI nr-aa BLAST: CBRC-BTAU-01-0582 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-BTAU-01-0582 ref|ZP_01115488.1| Permease of the major facilitator superfamily protein [Rein...ekea sp. MED297] gb|EAR08550.1| Permease of the major facilitator superfamily protein [Reinekea sp. MED297] ZP_01115488.1 0.003 29% ...

NCBI nr-aa BLAST: CBRC-LAFR-01-1577 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-LAFR-01-1577 ref|ZP_01754031.1| oligopeptide ABC transporter permease protein [Rose...obacter sp. SK209-2-6] gb|EBA17512.1| oligopeptide ABC transporter permease protein [Roseobacter sp. SK209-2-6] ZP_01754031.1 0.50 31% ...

Gap bowing in Inx Ga1-x N and Inx Al1-x N under pressure

DEFF Research Database (Denmark)

Gorczyca, I.; Suski, T.; Christensen, Niels Egede

2009-01-01

The electronic band structures of InxGa1-xN and InxAl1-xN alloys are calculated by ab-initio methods in a supercell geometry, and the effects of varying the composition and applying external pressure examined. Indium segregation is also simulated, and it is shown that it strongly influences the b...... the band gap and its pressure derivative. Both the band gaps and their pressure coefficients are considerably lower when In atoms are clustered, than when they are uniformly distributed.......The electronic band structures of InxGa1-xN and InxAl1-xN alloys are calculated by ab-initio methods in a supercell geometry, and the effects of varying the composition and applying external pressure examined. Indium segregation is also simulated, and it is shown that it strongly influences...

A GAP that Divides [version 1; referees: 3 approved

Directory of Open Access Journals (Sweden)

Angika Basant

2017-10-01

Full Text Available Cytokinesis in metazoan cells is mediated by an actomyosin-based contractile ring that assembles in response to activation of the small GTPase RhoA. The guanine nucleotide exchange factor that activates RhoA during cytokinesis, ECT-2, is highly regulated. In most metazoan cells, with the notable exception of the early Caenorhabditis elegans embryo, RhoA activation and furrow ingression require the centralspindlin complex. This exception is due to the existence of a parallel pathway for RhoA activation in C. elegans. Centralspindlin contains CYK-4 which contains a predicted Rho family GTPase-activating protein (GAP domain. The function of this domain has been the subject of considerable debate. Some publications suggest that the GAP domain promotes RhoA activation (for example, Zhang and Glotzer, 2015; Loria, Longhini and Glotzer, 2012, whereas others suggest that it functions to inactivate the GTPase Rac1 (for example, Zhuravlev et al., 2017. Here, we review the mechanisms underlying RhoA activation during cytokinesis, primarily focusing on data in C. elegans. We highlight the importance of considering the parallel pathway for RhoA activation and detailed analyses of cyk-4 mutant phenotypes when evaluating the role of the GAP domain of CYK-4.

Gap Resolution

Energy Technology Data Exchange (ETDEWEB)

2017-04-25

Gap Resolution is a software package that was developed to improve Newbler genome assemblies by automating the closure of sequence gaps caused by repetitive regions in the DNA. This is done by performing the follow steps:1) Identify and distribute the data for each gap in sub-projects. 2) Assemble the data associated with each sub-project using a secondary assembler, such as Newbler or PGA. 3) Determine if any gaps are closed after reassembly, and either design fakes (consensus of closed gap) for those that closed or lab experiments for those that require additional data. The software requires as input a genome assembly produce by the Newbler assembler provided by Roche and 454 data containing paired-end reads.

Scaling behavior of spin gap of the bond alternating anisotropic spin-1/2 Heisenberg chain

Energy Technology Data Exchange (ETDEWEB)

Paul, Susobhan, E-mail: suso.phy.paul@gmail.com [Department of Physics, Scottish Church College, 1 & 3 Urquhart Square, Kolkata-700006 (India); Ghosh, Asim Kumar, E-mail: asimkumar96@yahoo.com [Department of Physics, Jadavpur University, 188 Raja S C Mallik Road, Kolkata-700032 (India)

2016-05-06

Scaling behavior of spin gap of a bond alternating spin-1/2 anisotropic Heisenberg chain has been studied both in ferromagnetic (FM) and antiferromagnetic (AFM) cases. Spin gap has been estimated by using exact diagonalization technique. All those quantities have been obtained for a region of anisotropic parameter Δ defined by 0≤Δ≤1. Spin gap is found to develop as soon as the non-uniformity in the alternating bond strength is introduced in the AFM regime which furthermore sustains in the FM regime as well. Scaling behavior of the spin gap has been studied by introducing scaling exponent. The variation of scaling exponents with Δ is fitted with a regular function.

NCBI nr-aa BLAST: CBRC-DYAK-08-0032 [SEVENS

Lifescience Database Archive (English)

Full Text Available obable SP0913 [Streptococcus gordonii str. Challis substr. CH1] YP_001450777.1 0.013 25% ... ...CBRC-DYAK-08-0032 ref|YP_001450777.1| ABC transporter, permease protein, probable SP0913 [Streptococcus gord...onii str. Challis substr. CH1] gb|ABV09319.1| ABC transporter, permease protein, pr

NCBI nr-aa BLAST: CBRC-DYAK-08-0031 [SEVENS

Lifescience Database Archive (English)

Full Text Available obable SP0913 [Streptococcus gordonii str. Challis substr. CH1] YP_001450777.1 0.35 26% ... ...CBRC-DYAK-08-0031 ref|YP_001450777.1| ABC transporter, permease protein, probable SP0913 [Streptococcus gord...onii str. Challis substr. CH1] gb|ABV09319.1| ABC transporter, permease protein, pr

NCBI nr-aa BLAST: CBRC-DYAK-08-0041 [SEVENS

Lifescience Database Archive (English)

Full Text Available obable SP0913 [Streptococcus gordonii str. Challis substr. CH1] YP_001450777.1 0.003 24% ... ...CBRC-DYAK-08-0041 ref|YP_001450777.1| ABC transporter, permease protein, probable SP0913 [Streptococcus gord...onii str. Challis substr. CH1] gb|ABV09319.1| ABC transporter, permease protein, pr

RCP-driven α5β1 recycling suppresses Rac and promotes RhoA activity via the RacGAP1-IQGAP1 complex.

Science.gov (United States)

Jacquemet, Guillaume; Green, David M; Bridgewater, Rebecca E; von Kriegsheim, Alexander; Humphries, Martin J; Norman, Jim C; Caswell, Patrick T

2013-09-16

Inhibition of αvβ3 or expression of mutant p53 promotes invasion into fibronectin (FN)-containing extracellular matrix (ECM) by enhancing Rab-coupling protein (RCP)-dependent recycling of α5β1 integrin. RCP and α5β1 cooperatively recruit receptor tyrosine kinases, including EGFR1, to regulate their trafficking and downstream signaling via protein kinase B (PKB)/Akt, which, in turn, promotes invasive migration. In this paper, we identify a novel PKB/Akt substrate, RacGAP1, which is phosphorylated as a consequence of RCP-dependent α5β1 trafficking. Phosphorylation of RacGAP1 promotes its recruitment to IQGAP1 at the tips of invasive pseudopods, and RacGAP1 then locally suppresses the activity of the cytoskeletal regulator Rac and promotes the activity of RhoA in this subcellular region. This Rac to RhoA switch promotes the extension of pseudopodial processes and invasive migration into FN-containing matrices, in a RhoA-dependent manner. Thus, the localized endocytic trafficking of α5β1 within the tips of invasive pseudopods elicits signals that promote the reorganization of the actin cytoskeleton, protrusion, and invasion into FN-rich ECM.

Efficient photocatalytic degradation of perfluorooctanoic acid by a wide band gap p-block metal oxyhydroxide InOOH

Science.gov (United States)

Xu, Jingjing; Wu, Miaomiao; Yang, Jingwen; Wang, Zhengmei; Chen, Mindong; Teng, Fei

2017-09-01

In this work, we prepared a new wide band gap semiconductor, p-block metal oxyhydroxide InOOH, which exhibits efficient activity for perfluorooctanoic acid (PFOA) degradation under mild conditions and UV light irradiation. The apparent rate constant for PFOA degradation by InOOH is 27.6 times higher than that for P25 titania. Results show that ionized PFOA (C7F15COO-) can be adsorbed much more efficiently on the surface of InOOH than P25. Then, the adsorbed C7F15COO- can be decomposed directly by photo-generated holes to form C7F15COOrad radicals. This process is the key step for the photocalytic degradation of PFOA. Major degradation intermediates, fluoride ions and perfluorinated carboxylic acids (PFCAs) with shorter chain lengths were detected during PFOA degradation. A possible pathway for photocatalytic degradation of PFOA is proposed based on the experimental results. Therefore, this studies indicates a potential new material and method for the efficient treatment of PFCA pollutants under mild conditions.

NCBI nr-aa BLAST: CBRC-DNOV-01-1963 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DNOV-01-1963 ref|NP_622305.1| ABC-type nitrate/sulfonate/taurine/bicarbonate t...ransport systems, permease components [Thermoanaerobacter tengcongensis MB4] gb|AAM23909.1| ABC-type nitrate/sulfonate/taurine/bicarb...onate transport systems, permease components [Thermoanaerobacter tengcongensis MB4] NP_622305.1 0.013 26% ...

Band gaps of wurtzite Sc{sub x}Ga{sub 1−x}N alloys

Energy Technology Data Exchange (ETDEWEB)

Tsui, H. C. L.; Moram, M. A. [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Goff, L. E. [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Rhode, S. K. [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Pereira, S. [CICECO and Dept. Physics, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Beere, H. E.; Farrer, I.; Nicoll, C. A.; Ritchie, D. A. [Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2015-03-30

Optical transmittance measurements on epitaxial, phase-pure, wurtzite-structure Sc{sub x}Ga{sub 1−x}N films with 0 ≤ x ≤ 0.26 showed that their direct optical band gaps increased from 3.33 eV to 3.89 eV with increasing x, in agreement with theory. These films contained I{sub 1}- and I{sub 2}-type stacking faults. However, the direct optical band gaps decreased from 3.37 eV to 3.26 eV for Sc{sub x}Ga{sub 1−x}N films, which additionally contained nanoscale lamellar inclusions of the zinc-blende phase, as revealed by aberration-corrected scanning transmission electron microscopy. Therefore, we conclude that the apparent reduction in Sc{sub x}Ga{sub 1−x}N band gaps with increasing x is an artefact resulting from the presence of nanoscale zinc-blende inclusions.

RCP-driven α5β1 recycling suppresses Rac and promotes RhoA activity via the RacGAP1–IQGAP1 complex

Science.gov (United States)

Jacquemet, Guillaume; Green, David M.; Bridgewater, Rebecca E.; von Kriegsheim, Alexander; Humphries, Martin J.; Norman, Jim C.

2013-01-01

Inhibition of αvβ3 or expression of mutant p53 promotes invasion into fibronectin (FN)-containing extracellular matrix (ECM) by enhancing Rab-coupling protein (RCP)–dependent recycling of α5β1 integrin. RCP and α5β1 cooperatively recruit receptor tyrosine kinases, including EGFR1, to regulate their trafficking and downstream signaling via protein kinase B (PKB)/Akt, which, in turn, promotes invasive migration. In this paper, we identify a novel PKB/Akt substrate, RacGAP1, which is phosphorylated as a consequence of RCP-dependent α5β1 trafficking. Phosphorylation of RacGAP1 promotes its recruitment to IQGAP1 at the tips of invasive pseudopods, and RacGAP1 then locally suppresses the activity of the cytoskeletal regulator Rac and promotes the activity of RhoA in this subcellular region. This Rac to RhoA switch promotes the extension of pseudopodial processes and invasive migration into FN-containing matrices, in a RhoA-dependent manner. Thus, the localized endocytic trafficking of α5β1 within the tips of invasive pseudopods elicits signals that promote the reorganization of the actin cytoskeleton, protrusion, and invasion into FN-rich ECM. PMID:24019536

Involvement of AmpG in mediating a dynamic relationship between serine beta-lactamase induction and biofilm-forming ability of Escherichia coli.

Science.gov (United States)

Mallik, Dhriti; Pal, Shilpa; Ghosh, Anindya S

2018-04-01

AmpG permease is implicated both in beta-lactamase induction and peptidoglycan recycling in enterobacterial isolates. Here, physiological studies using molecular genetics show that deletion of AmpG permease dramatically increases beta-lactam susceptibility even in the presence of AmpC, TEM-1 and OXA beta-lactamases. Also, there is an appreciable decrease in the biofilm-forming ability of strains lacking this protein. Expression of this permease in excess probably compromises the integrity of the bacterial cells, leading to cell lysis. Based on these results, we propose that AmpG permease may be used as a potential antibiotic target and its suppression could efficiently inhibit both beta-lactamase induction and biofilm formation.

Novel acid mono azo dye compound: Synthesis, characterization, vibrational, optical and theoretical investigations of 2-[(E)-(8-hydroxyquinolin-5-yl)-diazenyl]-4,5-dimethoxybenzoic acid

Science.gov (United States)

Saçmacı, Mustafa; Çavuş, Hatice Kanbur; Arı, Hatice; Şahingöz, Recep; Özpozan, Talat

2012-11-01

Novel acid mono azo dye, 2-[(E)-(8-hydroxyquinolin-5yl)-diazenyl]-4,5-dimethoxybenzoic acid (HQD), was synthesized by coupling diazonium salt solution of 2-amino-4,5-dimethoxybenzoic acid (DMA) with 8-hydroxyquinoline (HQ). This dye was characterized by UV-vis, IR & Raman, 1H and 13C NMR spectroscopic techniques and elemental analysis. The normal coordinate analysis of HQD was also performed to assign each band in vibrational spectra. DFT (B3LYP and B3PW91) calculations were employed to optimize the geometry, to interpret NMR spectra, to calculate and to determine the stable tautomeric structure of the compound. Natural Bond Orbital (NBO) analysis was performed to investigate intramolecular interactions. The vibrational spectral data obtained from solid phase IR & Raman spectra were assigned based on the results of the theoretical calculations. UV-vis spectroscopic technique was employed to obtain the optical band gap of HQD. The analysis of the optical absorption data revealed the existence of direct and indirect transitions in the optical band gaps. The optical band gaps of HQD have been found 1.95 and 1.90 eV for direct and indirect transitions, respectively.

Observation of rapidity gaps in bar pp collisions at 1.8 TeV

International Nuclear Information System (INIS)

Abe, F.; Albrow, M.; Amidei, D.; Anway-Wiese, C.; Apollinari, G.; Atac, M.; Auchincloss, P.; Azzi, P.; Bacchetta, N.; Baden, A.R.; Badgett, W.; Bailey, M.W.; Bamberger, A.; de Barbaro, P.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Bartalini, P.; Bauer, G.; Baumann, T.; Bedeschi, F.; Behrends, S.; Belforte, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Benlloch, J.; Bensinger, J.; Beretvas, A.; Berge, J.P.; Bertolucci, S.; Biery, K.; Bhadra, S.; Binkley, M.; Bisello, D.; Blair, R.; Blocker, C.; Bodek, A.; Bolognesi, V.; Booth, A.W.; Boswell, C.; Brandenburg, G.; Brown, D.; Buckley-Geer, E.; Budd, H.S.; Busetto, G.; Byon-Wagner, A.; Byrum, K.L.; Campagnari, C.; Campbell, M.; Caner, A.; Carey, R.; Carithers, W.; Carlsmith, D.; Carroll, J.T.; Cashmore, R.; Castro, A.; Cen, Y.; Cervelli, F.; Chadwick, K.; Chapman, J.; Chiarelli, G.; Chinowsky, W.; Cihangir, S.; Clark, A.G.; Cobal, M.; Connor, D.; Contreras, M.; Cooper, J.; Cordelli, M.; Crane, D.; Cunningham, J.D.; Day, C.; DeJongh, F.; Dell'Agnello, S.; Dell'Orso, M.; Demortier, L.; Denby, B.; Derwent, P.F.; Devlin, T.; Dickson, M.; Donati, S.; Drucker, R.B.; Dunn, A.; Einsweiler, K.; Elias, J.E.; Ely, R.; Eno, S.; Errede, S.; Etchegoyen, A.; Farhat, B.; Feldman, G.J.; Flaugher, B.; Foster, G.W.; Franklin, M.; Frautschi, M.; Freeman, J.; Frisch, H.; Fuess, T.; Fukui, Y.; Gagliardi, G.; Garfinkel, A.F.; Gauthier, A.; Geer, S.; Gerdes, D.W.; Giannetti, P.; Giokaris, N.; Gladney, L.; Gold, M.; Gonzalez, J.; Goshaw, A.; Goulianos, K.; Grassmann, H.; Grieco, G.M.; Grindley, R.; Grosso-Pilcher, C.; Haber, C.; Hahn, S.R.; Handler, R.; Hara, K.; Harral, B.; Harris, R.M.; Hauger, S.A.; Hauser, J.; Hawk, C.; Hessing, T.; Hollebeek, R.; Holloway, L.; Hoelscher, A.; Hong, S.; Houk, G.; Hu, P.; Hubbard, B.; Huffman, B.T.; Hughes, R.; Hurst, P.; Huth, J.; Hylen, J.; Incagli, M.; Ino, T.; Iso, H.; Jensen, H.; Jessop, C.P.; Johnson, R.P.; Joshi, U.; Kadel, R.W.; Kamon, T.; Kanda, S.; Kardelis, D.A.; Karliner, I.

1995-01-01

In pp bar pp collisions at √s=1.8TeV we find jet events with a rapidity gap topology. The number of hadrons in the rapidity interval Δη D between leading-jet cones was sampled by charged tracks with P T >400MeV/c. We find excess trackless events beyond that expected in a smooth multiplicity distribution. In a control region outside Δη D we see no excess. For Δη D >0.8, the fraction of excess trackless events, consistent with estimates based on exchange of color-singlet digluons, is R(gap)=σ jet (gap)/σ jet = 0.0085±0.0012(stat) -0.0012 +0.0024 (syst)

GABA metabolism pathway genes, UGA1 and GAD1, regulate replicative lifespan in Saccharomycescerevisiae

Energy Technology Data Exchange (ETDEWEB)

Kamei, Yuka; Tamura, Takayuki [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Yoshida, Ryo [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Ohta, Shinji [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Fukusaki, Eiichiro [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mukai, Yukio, E-mail: y_mukai@nagahama-i-bio.ac.jp [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan)

2011-04-01

Highlights: {yields}We demonstrate that two genes in the yeast GABA metabolism pathway affect aging. {yields} Deletion of the UGA1 or GAD1 genes extends replicative lifespan. {yields} Addition of GABA to wild-type cultures has no effect on lifespan. {yields} Intracellular GABA levels do not differ in longevity mutants and wild-type cells. {yields} Levels of tricarboxylic acid cycle intermediates positively correlate with lifespan. -- Abstract: Many of the genes involved in aging have been identified in organisms ranging from yeast to human. Our previous study showed that deletion of the UGA3 gene-which encodes a zinc-finger transcription factor necessary for {gamma}-aminobutyric acid (GABA)-dependent induction of the UGA1 (GABA aminotransferase), UGA2 (succinate semialdehyde dehydrogenase), and UGA4 (GABA permease) genes-extends replicative lifespan in the budding yeast Saccharomycescerevisiae. Here, we found that deletion of UGA1 lengthened the lifespan, as did deletion of UGA3; in contrast, strains with UGA2 or UGA4 deletions exhibited no lifespan extension. The {Delta}uga1 strain cannot deaminate GABA to succinate semialdehyde. Deletion of GAD1, which encodes the glutamate decarboxylase that converts glutamate into GABA, also increased lifespan. Therefore, two genes in the GABA metabolism pathway, UGA1 and GAD1, were identified as aging genes. Unexpectedly, intracellular GABA levels in mutant cells (except for {Delta}uga2 cells) did not differ from those in wild-type cells. Addition of GABA to culture media, which induces transcription of the UGA structural genes, had no effect on replicative lifespan of wild-type cells. Multivariate analysis of {sup 1}H nuclear magnetic resonance spectra for the whole-cell metabolite levels demonstrated a separation between long-lived and normal-lived strains. Gas chromatography-mass spectrometry analysis of identified metabolites showed that levels of tricarboxylic acid cycle intermediates positively correlated with lifespan

GABA metabolism pathway genes, UGA1 and GAD1, regulate replicative lifespan in Saccharomycescerevisiae

International Nuclear Information System (INIS)

Kamei, Yuka; Tamura, Takayuki; Yoshida, Ryo; Ohta, Shinji; Fukusaki, Eiichiro; Mukai, Yukio

2011-01-01

Highlights: →We demonstrate that two genes in the yeast GABA metabolism pathway affect aging. → Deletion of the UGA1 or GAD1 genes extends replicative lifespan. → Addition of GABA to wild-type cultures has no effect on lifespan. → Intracellular GABA levels do not differ in longevity mutants and wild-type cells. → Levels of tricarboxylic acid cycle intermediates positively correlate with lifespan. -- Abstract: Many of the genes involved in aging have been identified in organisms ranging from yeast to human. Our previous study showed that deletion of the UGA3 gene-which encodes a zinc-finger transcription factor necessary for γ-aminobutyric acid (GABA)-dependent induction of the UGA1 (GABA aminotransferase), UGA2 (succinate semialdehyde dehydrogenase), and UGA4 (GABA permease) genes-extends replicative lifespan in the budding yeast Saccharomycescerevisiae. Here, we found that deletion of UGA1 lengthened the lifespan, as did deletion of UGA3; in contrast, strains with UGA2 or UGA4 deletions exhibited no lifespan extension. The Δuga1 strain cannot deaminate GABA to succinate semialdehyde. Deletion of GAD1, which encodes the glutamate decarboxylase that converts glutamate into GABA, also increased lifespan. Therefore, two genes in the GABA metabolism pathway, UGA1 and GAD1, were identified as aging genes. Unexpectedly, intracellular GABA levels in mutant cells (except for Δuga2 cells) did not differ from those in wild-type cells. Addition of GABA to culture media, which induces transcription of the UGA structural genes, had no effect on replicative lifespan of wild-type cells. Multivariate analysis of 1 H nuclear magnetic resonance spectra for the whole-cell metabolite levels demonstrated a separation between long-lived and normal-lived strains. Gas chromatography-mass spectrometry analysis of identified metabolites showed that levels of tricarboxylic acid cycle intermediates positively correlated with lifespan extension. These results strongly suggest

Evolution and variability of Solanum RanGAP2, a cofactor in the incompatible interaction between the resistance protein GPA2 and the Globodera pallida effector Gp-RBP-1.

Science.gov (United States)

Carpentier, Jean; Grenier, Eric; Esquibet, Magalie; Hamel, Louis-Philippe; Moffett, Peter; Manzanares-Dauleux, Maria J; Kerlan, Marie-Claire

2013-04-19

The Ran GTPase Activating Protein 2 (RanGAP2) was first described as a regulator of mitosis and nucleocytoplasmic trafficking. It was then found to interact with the Coiled-Coil domain of the Rx and GPA2 resistance proteins, which confer resistance to Potato Virus X (PVX) and potato cyst nematode Globodera pallida, respectively. RanGAP2 is thought to mediate recognition of the avirulence protein GP-RBP-1 by GPA2. However, the Gpa2-induced hypersensitive response appears to be relatively weak and Gpa2 is limited in terms of spectrum of efficiency as it is effective against only two nematode populations. While functional and evolutionary analyses of Gp-Rbp-1 and Gpa2 identified key residues in both the resistance and avirulence proteins that are involved in recognition determination, whether variation in RanGAP2 also plays a role in pathogen recognition has not been investigated. We amplified a total of 147 RanGAP2 sequences from 55 accessions belonging to 18 different di-and tetraploid Solanum species from the section Petota. Among the newly identified sequences, 133 haplotypes were obtained and 19.1% of the nucleotide sites were found to be polymorphic. The observed intra-specific nucleotide diversity ranges from 0.1 to 1.3%. Analysis of the selection pressures acting on RanGAP2 suggests that this gene evolved mainly under purifying selection. Nonetheless, we identified polymorphic positions in the protein sequence at the intra-specific level, which could modulate the activity of RanGAP2. Two polymorphic sites and a three amino-acid deletion in RanGAP2 were found to affect the timing and intensity of the Gpa2-induced hypersensitive response to avirulent GP-RBP-1 variants even though they did not confer any gain of recognition of virulent GP-RBP-1 variants. Our results highlight how a resistance gene co-factor can manage in terms of evolution both an established role as a cell housekeeping gene and an implication in plant parasite interactions. StRanGAP2 gene

Polyfluorinated alkyl phosphate ester surfactants - current knowledge and knowledge gaps

DEFF Research Database (Denmark)

Taxvig, Camilla; Rosenmai, Anna Kjerstine; Vinggaard, Anne Marie

2014-01-01

as in human blood, urine and milk. Due to their long half-life in human beings, there is an increased risk that exposure to these compounds can cause adverse effects. However, except for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), there is a large data gap regarding toxicological...

CdS_xTe_1_-_x ternary semiconductors band gaps calculation using ground state and GW approximations

International Nuclear Information System (INIS)

Kheloufi, Nawal; Bouzid, Abderrazak

2016-01-01

We present band gap calculations of zinc-blende ternary CdS_xTe_1_-_x semiconductors within the standard DFT and quasiparticle calculations employing pseudopotential method. The DFT, the local density approximation (LDA) and the Generalized Gradient Approximation (GGA) based calculations have given very poor results compared to experimental data. The quasiparticle calculations have been investigated via the one-shot GW approximation. The present paper discuses and confirms the effect of inclusion of the semicore states in the cadmium (Cd) pseudopotential. The obtained GW quasiparticle band gap using Cd"+"2"0 pseudopotential has been improved compared to the obtained results from the available pseudopotential without the treatment of semicore states. Our DFT and quasiparticle band gap results are discussed and compared to the available theoretical calculations and experimental data. - Graphical abstract: Band gaps improvement concerning the binary and ternary alloys using the GW approximation and Cd"2"0"+ pseudopotential with others levels of approximations (the LDA and GGA approximation employing the Cd"1"2"+ and the LDA within Cd"2"0"+ pseudopotential). - Highlights: • The direct Γ- Γ and indirect Γ- X and Γ- L bands gaps show a nonlinear behavior when S content is enhanced. • The quasiparticle band gap result for the investigated semiconductors is improved using the GW approximation. • All CdS_xTe_1_-_x compounds in all compositions range from 0 to 1 are direct band gap semiconductors.

Two S-wave gap symmetry for single crystals of the superconductor BaFe1.8Co0.2As2

International Nuclear Information System (INIS)

Choi, Ki-Young; Kim, Soo Hyun; Choi, Changho; Jung, Myung-Hwa; Wang, X.F.; Chen, X.H.; Noh, Jae Dong; Lee, Sung-IK

2010-01-01

To clarify the gap structure of the iron-pnictide superconductors, we synthesized optimally doped single crystals of BaFe 1.8 Co 0.2 As 2 , which had a critical temperature, T c , of 23.6 K. The initial M-H curve was used to find the lower critical field, H c1 . The full range of the temperature dependence of H c1 was explained by using a two S-wave gap symmetry. We estimate the two gap as Δ 1 (0) = 1.64 ± 0.2 meV for the small gap and Δ 2 (0) = 6.20 ± 0.2 meV for the large gap.

Connexin 43 Expression on Peripheral Blood Eosinophils: Role of Gap Junctions in Transendothelial Migration

Directory of Open Access Journals (Sweden)

Harissios Vliagoftis

2014-01-01

Full Text Available Eosinophils circulate in the blood and are recruited in tissues during allergic inflammation. Gap junctions mediate direct communication between adjacent cells and may represent a new way of communication between immune cells distinct from communication through cytokines and chemokines. We characterized the expression of connexin (Cx43 by eosinophils isolated from atopic individuals using RT-PCR, Western blotting, and confocal microscopy and studied the biological functions of gap junctions on eosinophils. The formation of functional gap junctions was evaluated measuring dye transfer using flow cytometry. The role of gap junctions on eosinophil transendothelial migration was studied using the inhibitor 18-a-glycyrrhetinic acid. Peripheral blood eosinophils express Cx43 mRNA and protein. Cx43 is localized not only in the cytoplasm but also on the plasma membrane. The membrane impermeable dye BCECF transferred from eosinophils to epithelial or endothelial cells following coculture in a dose and time dependent fashion. The gap junction inhibitors 18-a-glycyrrhetinic acid and octanol did not have a significant effect on dye transfer but reduced dye exit from eosinophils. The gap junction inhibitor 18-a-glycyrrhetinic acid inhibited eosinophil transendothelial migration in a dose dependent manner. Thus, eosinophils from atopic individuals express Cx43 constitutively and Cx43 may play an important role in eosinophil transendothelial migration and function in sites of inflammation.

The Wage Gap: Briefing Paper #1.

Science.gov (United States)

National Committee on Pay Equity, Washington, DC.

Women have made slow, steady progress in the labor market since 1979, but the wage gap has not narrowed significantly. This briefing paper updates a September 1987 paper based on "Male-Female Differences in Work Experience, Occupations, and Earnings: 1984" (Current Population Reports, Household Economic Studies, Series P-70, No. 10, issued in…

Gaps in nonsymmetric numerical semigroups

International Nuclear Information System (INIS)

Fel, Leonid G.; Aicardi, Francesca

2006-12-01

There exist two different types of gaps in the nonsymmetric numerical semigroups S(d 1 , . . . , d m ) finitely generated by a minimal set of positive integers {d 1 , . . . , d m }. We give the generating functions for the corresponding sets of gaps. Detailed description of both gap types is given for the 1st nontrivial case m = 3. (author)

A RAB3GAP1 SINE Insertion in Alaskan Huskies with Polyneuropathy, Ocular Abnormalities, and Neuronal Vacuolation (POANV Resembling Human Warburg Micro Syndrome 1 (WARBM1

Directory of Open Access Journals (Sweden)

Michaela Wiedmer

2016-02-01

Full Text Available We observed a hereditary phenotype in Alaskan Huskies that was characterized by polyneuropathy with ocular abnormalities and neuronal vacuolation (POANV. The affected dogs developed a progressive severe ataxia, which led to euthanasia between 8 and 16 months of age. The pedigrees were consistent with a monogenic autosomal recessive inheritance. We localized the causative genetic defect to a 4 Mb interval on chromosome 19 by a combined linkage and homozygosity mapping approach. Whole genome sequencing of one affected dog, an obligate carrier, and an unrelated control revealed a 218-bp SINE insertion into exon 7 of the RAB3GAP1 gene. The SINE insertion was perfectly associated with the disease phenotype in a cohort of 43 Alaskan Huskies, and it was absent from 541 control dogs of diverse other breeds. The SINE insertion induced aberrant splicing and led to a transcript with a greatly altered exon 7. RAB3GAP1 loss-of-function variants in humans cause Warburg Micro Syndrome 1 (WARBM1, which is characterized by additional developmental defects compared to canine POANV, whereas Rab3gap1-deficient mice have a much milder phenotype than either humans or dogs. Thus, the RAB3GAP1 mutant Alaskan Huskies provide an interesting intermediate phenotype that may help to better understand the function of RAB3GAP1 in development. Furthermore, the identification of the presumed causative genetic variant will enable genetic testing to avoid the nonintentional breeding of affected dogs.

Gap junctions and memory: an investigation using a single trial discrimination avoidance task for the neonate chick.

Science.gov (United States)

Verwey, L J; Edwards, T M

2010-02-01

Gap junctions are important to how the brain functions but are relatively under-investigated with respect to their contribution towards behaviour. In the present study a single trial discrimination avoidance task was used to investigate the effect of the gap junction inhibitor 18-alpha-glycyrrhetinic acid (alphaGA) on retention. Past studies within our research group have implied a potential role for gap junctions during the short-term memory (STM) stage which decays by 15 min post-training. A retention function study comparing 10 microM alphaGA and vehicle given immediately post-training demonstrated a significant main effect for drug with retention loss at all times of test (10-180 min post-training). Given that the most common gap junction in the brain is that forming the astrocytic network it is reasonable to conclude that alphaGA was acting upon these. To confirm this finding and interpretation two additional investigations were undertaken using endothelin-1 (ET-1) and ET-1+tolbutamide. Importantly, a retention function study using 10nM ET-1 replicated the retention loss observed for alphaGA. In order to confirm that ET-1 was acting on astrocytic gap junctions the amnestic action of ET-1 was effectively challenged with increasing concentrations of tolbutamide. The present findings suggest that astrocytic gap junctions are important for memory processing. Copyright 2009 Elsevier Inc. All rights reserved.

Caveolar fatty acids and acylation of caveolin-1.

Directory of Open Access Journals (Sweden)

Qian Cai

Full Text Available Caveolae are cholesterol and sphingolipids rich subcellular domains on plasma membrane. Caveolae contain a variety of signaling proteins which provide platforms for signaling transduction. In addition to enriched with cholesterol and sphingolipids, caveolae also contain a variety of fatty acids. It has been well-established that acylation of protein plays a pivotal role in subcellular location including targeting to caveolae. However, the fatty acid compositions of caveolae and the type of acylation of caveolar proteins remain largely unknown. In this study, we investigated the fatty acids in caveolae and caveolin-1 bound fatty acids.Caveolae were isolated from Chinese hamster ovary (CHO cells. The caveolar fatty acids were extracted with Folch reagent, methyl esterificated with BF3, and analyzed by gas chromatograph-mass spectrometer (GC/MS. The caveolin-1 bound fatty acids were immunoprecipitated by anti-caveolin-1 IgG and analyzed with GC/MS.In contrast to the whole CHO cell lysate which contained a variety of fatty acids, caveolae mainly contained three types of fatty acids, 0.48 µg palmitic acid, 0.61 µg stearic acid and 0.83 µg oleic acid/caveolae preparation/5 × 10(7 cells. Unexpectedly, GC/MS analysis indicated that caveolin-1 was not acylated by myristic acid; instead, it was acylated by palmitic acid and stearic acid.Caveolae contained a special set of fatty acids, highly enriched with saturated fatty acids, and caveolin-1 was acylated by palmitic acid and stearic acid. The unique fatty acid compositions of caveolae and acylation of caveolin-1 may be important for caveolae formation and for maintaining the function of caveolae.

Microstructural and Photoelectrochemical Properties of Gap-TiO2 Nano tubes

International Nuclear Information System (INIS)

Asma Husin Milad; Wan Ramli Daud; Asma Husin Milad; Wan Ramli Daud

2011-01-01

GaP/ TiO 2 / Ti arrays have been prepared via anodization of Ti foil and electrodeposition of GaP. TiO 2 nano tubes (TNT) were grown from a Ti foil by direct anodic oxidation using 0.5M phosphoric acid and 0.14 M NaF as electrolyte at 20 V for 45 min. Various concentrations aqueous solution of Ga(NO 3 ) 3 were used to deposit GaP nanoparticles onto the TNT in the electrodeposition step. Morphology and microstructure of GaP/ TNT were investigated by FESEM and XRD techniques. In addition the photocurrent of the GaP/ TNT were also investigated. It was found that the amount of GaP deposited on TNT considerably improved the efficiency of TNT as photo anode for photoelectrochemical applications. (author)

The RabGAP TBC1D1 plays a central role in exercise-regulated glucose metabolism in skeletal muscle

DEFF Research Database (Denmark)

Stöckli, Jacqueline; Meoli, Christopher C; Hoffman, Nolan J

2015-01-01

Insulin and exercise stimulate glucose uptake into skeletal muscle via different pathways. Both stimuli converge on the translocation of the glucose transporter GLUT4 from intracellular vesicles to the cell surface. Two Rab guanosine triphosphatases-activating proteins (GAPs) have been implicated...... weight, insulin action, and exercise. TBC1D1(-/-) mice showed normal glucose and insulin tolerance, with no difference in body weight compared with wild-type littermates. GLUT4 protein levels were reduced by ∼40% in white TBC1D1(-/-) muscle, and TBC1D1(-/-) mice showed impaired exercise endurance...... together with impaired exercise-mediated 2-deoxyglucose uptake into white but not red muscles. These findings indicate that the RabGAP TBC1D1 plays a key role in regulating GLUT4 protein levels and in exercise-mediated glucose uptake in nonoxidative muscle fibers....

Magical mystery tour: Salicylic acid signalling

Czech Academy of Sciences Publication Activity Database

Janda, Martin; Ruelland, E.

2015-01-01

Roč. 114, Special Issue (2015), s. 117-128 ISSN 0098-8472 R&D Projects: GA ČR(CZ) GAP501/11/1654 Institutional support: RVO:61389030 Keywords : Salicylic acid (SA) * NPR1 * SA overaccumulating mutants Subject RIV: ED - Physiology Impact factor: 3.712, year: 2015

Mechanics of Fluid-Filled Interstitial Gaps. II. Gap Characteristics in Xenopus Embryonic Ectoderm.

Science.gov (United States)

Barua, Debanjan; Parent, Serge E; Winklbauer, Rudolf

2017-08-22

The ectoderm of the Xenopus embryo is permeated by a network of channels that appear in histological sections as interstitial gaps. We characterized this interstitial space by measuring gap sizes, angles formed between adjacent cells, and curvatures of cell surfaces at gaps. From these parameters, and from surface-tension values measured previously, we estimated the values of critical mechanical variables that determine gap sizes and shapes in the ectoderm, using a general model of interstitial gap mechanics. We concluded that gaps of 1-4 μm side length can be formed by the insertion of extracellular matrix fluid at three-cell junctions such that cell adhesion is locally disrupted and a tension difference between cell-cell contacts and the free cell surface at gaps of 0.003 mJ/m 2 is generated. Furthermore, a cell hydrostatic pressure of 16.8 ± 1.7 Pa and an interstitial pressure of 3.9 ± 3.6 Pa, relative to the central blastocoel cavity of the embryo, was found to be consistent with the observed gap size and shape distribution. Reduction of cell adhesion by the knockdown of C-cadherin increased gap volume while leaving intracellular and interstitial pressures essentially unchanged. In both normal and adhesion-reduced ectoderm, cortical tension of the free cell surfaces at gaps does not return to the high values characteristic of the free surface of the whole tissue. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Superconducting energy gap of BaPb/sub 1-//sub x/Bi/sub x/O3

International Nuclear Information System (INIS)

Schlesinger, Z.; Collins, R.T.; Scott, B.A.; Calise, J.A.

1988-01-01

We report the first infrared measurement of the superconducting energy gap of BaPb/sub 1-//sub x/Bi/sub x/O 3 . In our polycrystalline samples with T/sub c/≅9.5 K (x≅0.2) we obtain 2Δ≅3.2kT/sub c/, roughly in agreement with the weak-coupling Bardeen-Cooper-Schrieffer prediction, 2Δ = 3.5kT/sub c/, and with tunneling measurements of the gap. We do not observe any structure above the gap energy associated with strong coupling

Incorporation of Oxygen into Abscisic Acid and Phaseic Acid from Molecular Oxygen 1

Science.gov (United States)

Creelman, Robert A.; Zeevaart, Jan A. D.

1984-01-01

Abscisic acid accumulates in detached, wilted leaves of Xanthium strumarium. When these leaves are subsequently rehydrated, phaseic acid, a catabolite of abscisic acid, accumulates. Analysis by gas chromatography-mass spectrometry of phaseic acid isolated from stressed and subsequently rehydrated leaves placed in an atmosphere containing 20% 18O2 and 80% N2 indicates that one atom of 18O is incorporated in the 6′-hydroxymethyl group of phaseic acid. This suggests that the enzyme that converts abscisic acid to phaseic acid is an oxygenase. Analysis by gas chromatography-mass spectrometry of abscisic acid isolated from stressed leaves kept in an atmosphere containing 18O2 indicates that one atom of 18O is present in the carboxyl group of abscisic acid. Thus, when abscisic acid accumulates in water-stressed leaves, only one of the four oxygens present in the abscisic acid molecule is derived from molecular oxygen. This suggests that either (a) the oxygen present in the 1′-, 4′-, and one of the two oxygens at the 1-position of abscisic acid arise from water, or (b) there exists a stored precursor with oxygen atoms already present in the 1′- and 4′-positions of abscisic acid which is converted to abscisic acid under conditions of water stress. PMID:16663564

Structural Dynamics of Tropical Moist Forest Gaps

Science.gov (United States)

Hunter, Maria O.; Keller, Michael; Morton, Douglas; Cook, Bruce; Lefsky, Michael; Ducey, Mark; Saleska, Scott; de Oliveira, Raimundo Cosme; Schietti, Juliana

2015-01-01

Gap phase dynamics are the dominant mode of forest turnover in tropical forests. However, gap processes are infrequently studied at the landscape scale. Airborne lidar data offer detailed information on three-dimensional forest structure, providing a means to characterize fine-scale (1 m) processes in tropical forests over large areas. Lidar-based estimates of forest structure (top down) differ from traditional field measurements (bottom up), and necessitate clear-cut definitions unencumbered by the wisdom of a field observer. We offer a new definition of a forest gap that is driven by forest dynamics and consistent with precise ranging measurements from airborne lidar data and tall, multi-layered tropical forest structure. We used 1000 ha of multi-temporal lidar data (2008, 2012) at two sites, the Tapajos National Forest and Ducke Reserve, to study gap dynamics in the Brazilian Amazon. Here, we identified dynamic gaps as contiguous areas of significant growth, that correspond to areas > 10 m2, with height gap at Tapajos National Forest (4.8 %) as compared to Ducke Reserve (2.0 %). On average, gaps were smaller at Ducke Reserve and closed slightly more rapidly, with estimated height gains of 1.2 m y-1 versus 1.1 m y-1 at Tapajos. At the Tapajos site, height growth in gap centers was greater than the average height gain in gaps (1.3 m y-1 versus 1.1 m y-1). Rates of height growth between lidar acquisitions reflect the interplay between gap edge mortality, horizontal ingrowth and gap size at the two sites. We estimated that approximately 10 % of gap area closed via horizontal ingrowth at Ducke Reserve as opposed to 6 % at Tapajos National Forest. Height loss (interpreted as repeat damage and/or mortality) and horizontal ingrowth accounted for similar proportions of gap area at Ducke Reserve (13 % and 10 %, respectively). At Tapajos, height loss had a much stronger signal (23 % versus 6 %) within gaps. Both sites demonstrate limited gap contagiousness defined by an

Development of Multidimensional Gap Conductance model using Virtual Link Gap Element

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyo Chan; Yang, Yong Sik; Kim, Dae Ho; Bang, Je Geon; Kim, Sun Ki; Koo, Yang Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

The gap conductance that determines temperature gradient between pellet and cladding can be quite sensitive to gap thickness. For instance, once the gap size increases up to several micrometers in certain region, difference of pellet surface temperatures increases up to 100 Kelvin. Therefore, iterative thermo-mechanical coupled analysis is required to solve temperature distribution throughout pellet and cladding. Recently, multidimensional fuel performance codes have been being developed in the advanced countries to evaluate thermal behavior of fuel for off normal conditions and DBA(design based accident) conditions using the Finite Element Method (FEM). FRAPCON-FRAPTRAN code system, which is well known as the verified and reliable code, incorporates 1D thermal module and multidimensional mechanical module. In this code, multidimensional gap conductance model is not applied. ALCYONE developed by CEA introduces equivalent heat convection coefficient that represents multidimensional gap conductance as a function of gap thickness. BISON, which is multidimensional fuel performance code developed by INL, owns multidimensional gap conductance model using projected thermal contact. In general, thermal contact algorithm is nonlinear calculation which is expensive approach numerically. The gap conductance model for multi-dimension is difficult issue in terms of convergence and nonlinearity because gap conductance is function of gap thickness which depends on mechanical analysis at each iteration step. In this paper, virtual link gap (VLG) element has been proposed to resolve convergence issue and nonlinear characteristic of multidimensional gap conductance. In terms of calculation accuracy and convergence efficiency, the proposed VLG model was evaluated. LWR fuel performance codes should incorporate thermo-mechanical loop to solve gap conductance problem, iteratively. However, gap conductance in multidimensional model is difficult issue owing to its nonlinearity and

Configurations, band structures and photocurrent responses of 4-(4-oxopyridin-1(4H)-yl)phthalic acid and its metal-organic frameworks

Energy Technology Data Exchange (ETDEWEB)

Yan, Xingxiu; Qiu, Xiandeng; Yan, Zhishuo; Li, Hongjiang [Department of Applied Chemistry, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Gong, Yun, E-mail: gongyun7211@cqu.edu.cn [Department of Applied Chemistry, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Lin, Jianhua, E-mail: jhlin@pku.edu.cn [Department of Applied Chemistry, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

2016-05-15

4-(4-oxopyridin-1(4 H)-yl)phthalic acid (H{sub 2}L) and three H{sub 2}L-based metal-organic frameworks (MOFs) formulated as ZnL(DPE)(H{sub 2}O)·H{sub 2}O (DPE=(E)-1, 2-di(pyridine −4-yl)ethene) (1), CdL(H{sub 2}O){sub 2} (2) and CdL (3) were synthesized and structurally characterized by single-crystal X-ray diffraction. The free H{sub 2}L ligand shows an enol-form and the L{sup 2−} ligand in the three MOFs exists as the keto-form. Density functional theory (DFT) calculations indicate H{sub 2}L and the three MOFs possess different band structures. Due to the existence of the N-donor, DPE in MOF 1, the conduction band (CB) minimum and band gap of MOF 1 are much lower than those of H{sub 2}L. And MOF 1 yielded much larger photocurrent density than H{sub 2}L upon visible light illumination. Electrochemical impedance spectroscopy (EIS) shows the interfacial charge transfer impedance in the presence of MOF 1 is lower than that in the presence of H{sub 2}L. The hydrous MOF 2 and the anhydrous MOF 3 are both constructed by Cd(II) and L{sup 2−}, and they can be reversibly transformed to each other. However, MOFs 2 and 3 possess different CB minimums and VB maximums, and their band gaps are much larger than that of MOF 1. - Graphical abstract: The free ligand, 4-(4-oxopyridin-1(4H)-yl)phthalic acid (H{sub 2}L) shows different configuration from its three MOFs, and they possess different band structures. MOF 1 yielded much larger visible-light-driven photocurrent density than H{sub 2}L. The hydrous MOF 2 and the anhydrous MOF 3 can be transformed to each other, and they have larger band gaps than MOF 1.

Endocytosis of a maltose permease is induced when amylolytic enzyme production is repressed in Aspergillus oryzae.

Science.gov (United States)

Hiramoto, Tetsuya; Tanaka, Mizuki; Ichikawa, Takanori; Matsuura, Yuka; Hasegawa-Shiro, Sachiko; Shintani, Takahiro; Gomi, Katsuya

2015-09-01

In the filamentous fungus Aspergillus oryzae, amylolytic enzyme production is induced by the presence of maltose. Previously, we identified a putative maltose permease (MalP) gene in the maltose-utilizing cluster of A. oryzae. malP disruption causes a significant decrease in α-amylase activity and maltose consumption, indicating that MalP is a maltose transporter required for amylolytic enzyme production in A. oryzae. Although the expression of amylase genes and malP is repressed by the presence of glucose, the effect of glucose on the abundance of functional MalP is unknown. In this study, we examined the effect of glucose and other carbon sources on the subcellular localization of green fluorescence protein (GFP)-tagged MalP. After glucose addition, GFP-MalP at the plasma membrane was internalized and delivered to the vacuole. This glucose-induced internalization of GFP-MalP was inhibited by treatment with latrunculin B, an inhibitor of actin polymerization. Furthermore, GFP-MalP internalization was inhibited by repressing the HECT ubiquitin ligase HulA (ortholog of yeast Rsp5). These results suggest that MalP is transported to the vacuole by endocytosis in the presence of glucose. Besides glucose, mannose and 2-deoxyglucose also induced the endocytosis of GFP-MalP and amylolytic enzyme production was inhibited by the addition of these sugars. However, neither the subcellular localization of GFP-MalP nor amylolytic enzyme production was influenced by the addition of xylose or 3-O-methylglucose. These results imply that MalP endocytosis is induced when amylolytic enzyme production is repressed. Copyright © 2015 Elsevier Inc. All rights reserved.

E1 Gap of Wurtzite InAs Single Nanowires Measured by Means of Resonant Raman Spectroscopy

International Nuclear Information System (INIS)

Moeller, M.; Lima, M. M. Jr. de; Cantarero, A.; Dacal, L. C. O.; Iikawa, F.; Chiaramonte, T.; Cotta, M. A.

2011-01-01

Indium arsenide nanowires were synthesized with an intermixing of wurtzite and zincblende structure by chemical beam epitaxy with the vapor-liquid-solid mechanism. Resonant Raman spectroscopy of the transverse optical phonon mode at 215 cm -1 reveals an E 1 gap of 2.47 eV which is assigned to the electronic band gap at the A point in the indium arsenide wurtzite phase.

E1 Gap of Wurtzite InAs Single Nanowires Measured by Means of Resonant Raman Spectroscopy

Science.gov (United States)

Möller, M.; Dacal, L. C. O.; de Lima, M. M.; Iikawa, F.; Chiaramonte, T.; Cotta, M. A.; Cantarero, A.

2011-12-01

Indium arsenide nanowires were synthesized with an intermixing of wurtzite and zincblende structure by chemical beam epitaxy with the vapor-liquid-solid mechanism. Resonant Raman spectroscopy of the transverse optical phonon mode at 215 cm-1 reveals an E1 gap of 2.47 eV which is assigned to the electronic band gap at the A point in the indium arsenide wurtzite phase.

Production of mouse monoclonal antibody against Streptococcus dysgalactiae GapC protein and mapping its conserved B-cell epitope.

Science.gov (United States)

Zhang, Limeng; Zhang, Hua; Fan, Ziyao; Zhou, Xue; Yu, Liquan; Sun, Hunan; Wu, Zhijun; Yu, Yongzhong; Song, Baifen; Ma, Jinzhu; Tong, Chunyu; Zhu, Zhanbo; Cui, Yudong

2015-02-01

Streptococcus dysgalactiae (S. dysgalactiae) GapC protein is a protective antigen that induces partial immunity against S. dysgalactiae infection in animals. To identify the conserved B-cell epitope of S. dysgalactiae GapC, a mouse monoclonal antibody 1E11 (mAb1E11) against GapC was generated and used to screen a phage-displayed 12-mer random peptide library (Ph.D.-12). Eleven positive clones recognized by mAb1E11 were identified, most of which matched the consensus motif TGFFAKK. Sequence of the motif exactly matched amino acids 97-103 of the S. dysgalactiae GapC. In addition, the epitope (97)TGFFAKK(103) showed high homology among different streptococcus species. Site-directed mutagenic analysis further confirmed that residues G98, F99, F100 and K103 formed the core of (97)TGFFAKK(103), and this core motif was the minimal determinant of the B-cell epitope recognized by the mAb1E11. Collectively, the identification of conserved B-cell epitope within S. dysgalactiae GapC highlights the possibility of developing the epitope-based vaccine. Copyright © 2014 Elsevier Ltd. All rights reserved.

Structural analyses of Legionella LepB reveal a new GAP fold that catalytically mimics eukaryotic RasGAP.

Science.gov (United States)

Yu, Qin; Hu, Liyan; Yao, Qing; Zhu, Yongqun; Dong, Na; Wang, Da-Cheng; Shao, Feng

2013-06-01

Rab GTPases are emerging targets of diverse bacterial pathogens. Here, we perform biochemical and structural analyses of LepB, a Rab GTPase-activating protein (GAP) effector from Legionella pneumophila. We map LepB GAP domain to residues 313-618 and show that the GAP domain is Rab1 specific with a catalytic activity higher than the canonical eukaryotic TBC GAP and the newly identified VirA/EspG family of bacterial RabGAP effectors. Exhaustive mutation analyses identify Arg444 as the arginine finger, but no catalytically essential glutamine residues. Crystal structures of LepB313-618 alone and the GAP domain of Legionella drancourtii LepB in complex with Rab1-GDP-AlF3 support the catalytic role of Arg444, and also further reveal a 3D architecture and a GTPase-binding mode distinct from all known GAPs. Glu449, structurally equivalent to TBC RabGAP glutamine finger in apo-LepB, undergoes a drastic movement upon Rab1 binding, which induces Rab1 Gln70 side-chain flipping towards GDP-AlF3 through a strong ionic interaction. This conformationally rearranged Gln70 acts as the catalytic cis-glutamine, therefore uncovering an unexpected RasGAP-like catalytic mechanism for LepB. Our studies highlight an extraordinary structural and catalytic diversity of RabGAPs, particularly those from bacterial pathogens.

INPP Unit 1 1998 Graphite - Pressure Tube Gap Measurements

International Nuclear Information System (INIS)

Bickel, J.H.

1999-01-01

Different analyses provide differing results depending upon criteria, assumptions and methodology used. Although the results are not directly comparable, they do not differ greatly in the low, medium and high estimate ranges. From 3 to 6 years it is likely more than one gap has closed and some may have been closed for several years. Beyond 6 years it is highly likely that many gaps are closed and have been for a long time

Band gap calculations of the semiconductor BNxP1−x using modified Becke–Johnson approximation

International Nuclear Information System (INIS)

Benkraouda, M.; Amrane, N.

2013-01-01

Highlights: ► The Modified Becke–Johnson scheme gives a very accurate band gap. ► We have shown the invalidity of Vegard’s linear rule for BN x P 1−x . ► The band gap changes with alloy concentration are important in band gap engineering. - Abstract: In this work, the electronic properties of BN, BP and BN x P 1−x compounds have been investigated by means of first-principles density-functional total-energy calculation using the all-electron full potential linear augmented plane-wave method (FP-LAPW). The (FP-LAPW) method was used within the density functional theory (DFT) along with the Engel–Vosko and Becke–Johnson exchange correlation potential. The energy bands along high symmetry directions, the density of states and bowing distributions are calculated. The results have been discussed in terms of previously existing experimental and theoretical data, and comparisons with similar compounds have been made. Analysis of band structure suggests direct and pseudo-direct band gaps for both compounds.

Folic acid and pantothenic acid protection against valproic acid-induced neural tube defects in CD-1 mice

Energy Technology Data Exchange (ETDEWEB)

Dawson, Jennifer E [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Raymond, Angela M [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Winn, Louise M [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada)

2006-03-01

In utero exposure to valproic acid (VPA) during pregnancy is associated with an increased risk of neural tube defects (NTDs). Although the mechanism by which VPA mediates these effects is unknown, VPA-initiated changes in embryonic protein levels have been implicated. The objectives of this study were to investigate the effect of in utero VPA exposure on embryonic protein levels of p53, NF-{kappa}B, Pim-1, c-Myb, Bax, and Bcl-2 in the CD-1 mouse. We also evaluated the protective effects of folic acid and pantothenic acid on VPA-induced NTDs and VPA-induced embryonic protein changes in this model. Pregnant CD-1 mice were administered a teratogenic dose of VPA prior to neural tube closure and embryonic protein levels were analyzed. In our study, VPA (400 mg/kg)-induced NTDs (24%) and VPA-exposed embryos with an NTD showed a 2-fold increase in p53, and 4-fold decreases in NF-{kappa}B, Pim-1, and c-Myb protein levels compared to their phenotypically normal littermates (P < 0.05). Additionally, VPA increased the ratio of embryonic Bax/Bcl-2 protein levels (P < 0.05). Pretreatment of pregnant dams with either folic acid or pantothenic acid prior to VPA significantly protected against VPA-induced NTDs (P < 0.05). Folic acid also reduced VPA-induced alterations in p53, NF-{kappa}B, Pim-1, c-Myb, and Bax/Bcl-2 protein levels, while pantothenic acid prevented VPA-induced alterations in NF-{kappa}B, Pim-1, and c-Myb. We hypothesize that folic acid and pantothenic acid protect CD-1 embryos from VPA-induced NTDs by independent, but not mutually exclusive mechanisms, both of which may be mediated by the prevention of VPA-induced alterations in proteins involved in neurulation.

Liver protective effect of ursodeoxycholic acid includes regulation of ADAM17 activity

Czech Academy of Sciences Publication Activity Database

Buryová, Halka; Chalupský, Karel; Žbodáková, Olga; Kanchev, Ivan; Jiroušková, Markéta; Gregor, Martin; Sedláček, Radislav

2013-01-01

Roč. 13, 30.10.2013 (2013), s. 155-155 ISSN 1471-230X R&D Projects: GA ČR GAP305/10/2143; GA ČR GAP303/10/2044; GA AV ČR IAA500520812; GA MŠk ED1.1.00/02.0109 Institutional support: RVO:68378050 Keywords : ursodeoxycholic acid * ADAM17 * shedding * cholestasis * liver Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.113, year: 2013

Alkali production associated with malolactic fermentation by oral streptococci and protection against acid, oxidative, or starvation damage.

Science.gov (United States)

Sheng, Jiangyun; Baldeck, Jeremiah D; Nguyen, Phuong T M; Quivey, Robert G; Marquis, Robert E

2010-07-01

Alkali production by oral streptococci is considered important for dental plaque ecology and caries moderation. Recently, malolactic fermentation (MLF) was identified as a major system for alkali production by oral streptococci, including Streptococcus mutans. Our major objectives in the work described in this paper were to further define the physiology and genetics of MLF of oral streptococci and its roles in protection against metabolic stress damage. L-Malic acid was rapidly fermented to L-lactic acid and CO(2) by induced cells of wild-type S. mutans, but not by deletion mutants for mleS (malolactic enzyme) or mleP (malate permease). Mutants for mleR (the contiguous regulator gene) had intermediate capacities for MLF. Loss of capacity to catalyze MLF resulted in loss of capacity for protection against lethal acidification. MLF was also found to be protective against oxidative and starvation damage. The capacity of S. mutans to produce alkali from malate was greater than its capacity to produce acid from glycolysis at low pH values of 4 or 5. MLF acted additively with the arginine deiminase system for alkali production by Streptococcus sanguinis, but not with urease of Streptococcus salivarius. Malolactic fermentation is clearly a major process for alkali generation by oral streptococci and for protection against environmental stresses.

Alkali production associated with malolactic fermentation by oral streptococci and protection against acid, oxidative, or starvation damage

Science.gov (United States)

Sheng, Jiangyun; Baldeck, Jeremiah D.; Nguyen, Phuong T.M.; Quivey, Robert G.; Marquis, Robert E.

2011-01-01

Alkali production by oral streptococci is considered important for dental plaque ecology and caries moderation. Recently, malolactic fermentation (MLF) was identified as a major system for alkali production by oral streptococci, including Streptococcus mutans. Our major objectives in the work described in this paper were to further define the physiology and genetics of MLF of oral streptococci and its roles in protection against metabolic stress damage. l-Malic acid was rapidly fermented to l-lactic acid and CO2 by induced cells of wild-type S. mutans, but not by deletion mutants for mleS (malolactic enzyme) or mleP (malate permease). Mutants for mleR (the contiguous regulator gene) had intermediate capacities for MLF. Loss of capacity to catalyze MLF resulted in loss of capacity for protection against lethal acidification. MLF was also found to be protective against oxidative and starvation damage. The capacity of S. mutans to produce alkali from malate was greater than its capacity to produce acid from glycolysis at low pH values of 4 or 5. MLF acted additively with the arginine deiminase system for alkali production by Streptococcus sanguinis, but not with urease of Streptococcus salivarius. Malolactic fermentation is clearly a major process for alkali generation by oral streptococci and for protection against environmental stresses. PMID:20651853

Primary and secondary kinetic isotope effects in the acid-catalyzed dehydration of 1,1'-diadamantylmethylcarbinol in aqueous acetic acid

International Nuclear Information System (INIS)

Lomas, J.S.

1981-01-01

The sulfuric acid catalyzed dehydration of 1,1'-diadamantyl-methylcarbinol in anhydrous acetic acid proceeds exclusively to 1,1'-bis(1-adamantyl)ethylene. The secondary deuterium isotope effect of 1.32 found for this reaction shows that carbonium ion formation from the protonated alcohol is rate determining. In the presence of water, however, capture of the carbonium ion competes with deprotonation, introducing a primary isotope effect. Consequently, the overall KIE rises, reaching 3.18 for 80% aqueous acetic acid. Analysis of the KIE for 80 to 100% aqueous acetic acid is consistent with a simple classical mechanism involving reversible formation of the intermediate carbonium ion. The primary isotope effect upon deprotonation is at the most 2.98, indicative of an asymmetric transition state close to the carbonium ion

Identification of a conserved B-cell epitope on the GapC protein of Streptococcus dysgalactiae.

Science.gov (United States)

Zhang, Limeng; Zhou, Xue; Fan, Ziyao; Tang, Wei; Chen, Liang; Dai, Jian; Wei, Yuhua; Zhang, Jianxin; Yang, Xuan; Yang, Xijing; Liu, Daolong; Yu, Liquan; Zhang, Hua; Wu, Zhijun; Yu, Yongzhong; Sun, Hunan; Cui, Yudong

2015-01-01

Streptococcus dysgalactiae (S. dysgalactia) GapC is a highly conserved surface dehydrogenase among the streptococcus spp., which is responsible for inducing protective antibody immune responses in animals. However, the B-cell epitope of S. dysgalactia GapC have not been well characterized. In this study, a monoclonal antibody 1F2 (mAb1F2) against S. dysgalactiae GapC was generated by the hybridoma technique and used to screen a phage-displayed 12-mer random peptide library (Ph.D.-12) for mapping the linear B-cell epitope. The mAb1F2 recognized phages displaying peptides with the consensus motif TRINDLT. Amino acid sequence of the motif exactly matched (30)TRINDLT(36) of the S. dysgalactia GapC. Subsequently, site-directed mutagenic analysis further demonstrated that residues R31, I32, N33, D34 and L35 formed the core of (30)TRINDLT(36), and this core motif was the minimal determinant of the B-cell epitope recognized by the mAb1F2. The epitope (30)TRINDLT(36) showed high homology among different streptococcus species. Overall, our findings characterized a conserved B-cell epitope, which will be useful for the further study of epitope-based vaccines. Copyright © 2015 Elsevier Ltd. All rights reserved.

GAP WIDTH STUDY IN LASER BUTT-WELDING

DEFF Research Database (Denmark)

Gong, Hui; Olsen, Flemming Ove

power : 2 and 2.6 kW and the focal point position : 0 and -1.2 mm. Quality of all the butt welds are destructively tested according to ISO 13919-1.Influences of the variable process parameters to the maximum allowable gap width are observed as (1) the maximum gap width is inversely related......In this paper the maximum allowable gap width in laser butt-welding is intensively studied. The gap width study (GWS) is performed on the material of SST of W1.4401 (AISI 316) under various welding conditions, which are the gap width : 0.00-0.50 mm, the welding speed : 0.5-2.0 m/min, the laser...... to the welding speed, (2) the larger laser power leads to the bigger maximum allowable gap width and (3) the focal point position has very little influence on the maximum gap width....

Improved α-Amylase Production by Dephosphorylation Mutation of CreD, an Arrestin-Like Protein Required for Glucose-Induced Endocytosis of Maltose Permease and Carbon Catabolite Derepression in Aspergillus oryzae.

Science.gov (United States)

Tanaka, Mizuki; Hiramoto, Tetsuya; Tada, Hinako; Shintani, Takahiro; Gomi, Katsuya

2017-07-01

Aspergillus oryzae produces copious amount of amylolytic enzymes, and MalP, a major maltose permease, is required for the expression of amylase-encoding genes. The expression of these genes is strongly repressed by carbon catabolite repression (CCR) in the presence of glucose. MalP is transported from the plasma membrane to the vacuole by endocytosis, which requires the homolog of E6-AP carboxyl terminus ubiquitin ligase HulA, an ortholog of yeast Rsp5. In yeast, arrestin-like proteins mediate endocytosis as adaptors of Rsp5 and transporters. In the present study, we examined the involvement of CreD, an arrestin-like protein, in glucose-induced MalP endocytosis and CCR of amylase-encoding genes. Deletion of creD inhibited the glucose-induced endocytosis of MalP, and CreD showed physical interaction with HulA. Phosphorylation of CreD was detected by Western blotting, and two serine residues were determined as the putative phosphorylation sites. However, the phosphorylation state of the serine residues did not regulate MalP endocytosis and its interaction with HulA. Although α-amylase production was significantly repressed by creD deletion, both phosphorylation and dephosphorylation mimics of CreD had a negligible effect on α-amylase activity. Interestingly, dephosphorylation of CreD was required for CCR relief of amylase genes that was triggered by disruption of the deubiquitinating enzyme-encoding gene creB The α-amylase activity of the creB mutant was 1.6-fold higher than that of the wild type, and the dephosphorylation mimic of CreD further improved the α-amylase activity by 2.6-fold. These results indicate that a combination of the dephosphorylation mutation of CreD and creB disruption increased the production of amylolytic enzymes in A. oryzae IMPORTANCE In eukaryotes, glucose induces carbon catabolite repression (CCR) and proteolytic degradation of plasma membrane transporters via endocytosis. Glucose-induced endocytosis of transporters is mediated by

Study of natural convection characteristics in a narrow annular gap in (Part 1)

International Nuclear Information System (INIS)

Narahara, Nobuyuki; Uotani, Masaki; Kinoshita, Izumi

1986-01-01

To clarify the characteristics of natural convection in a narrow annular gap at the roof-slab penetrations in pool-type LMFBR, preliminary and visualization experiments were carried out. The results are summarized as follows. (1) In the preliminary experiment having the upper and bottom closed annular space nondimensional circumferential temperature difference increases with gap width decreasing, and decreses with Rayleigh number increasing at the range of rayleigh number 10 10 to 10 11 . (2) In the visualization experiment, which consists the upper and bottom closed annular space type apparatus and the upper-closed bottom-open type apparatus, flow pattern and its effect at temperature distribution are clarified. (author)

Relevance of Peptide Uptake Systems to the Physiology and Virulence of Streptococcus agalactiae

OpenAIRE

Samen, Ulrike; Gottschalk, Birgit; Eikmanns, Bernhard J.; Reinscheid, Dieter J.

2004-01-01

Streptococcus agalactiae is a major cause of invasive infections in human newborns. To satisfy its growth requirements, S. agalactiae takes up 9 of the 20 proteinogenic amino acids from the environment. Defined S. agalactiae mutants in one or several of four putative peptide permease systems were constructed and tested for peptide uptake, growth in various media, and expression of virulence traits. Oligopeptide uptake by S. agalactiae was shown to be mediated by the ABC transporter OppA1-F, w...

Rewiring the reductive tricarboxylic acid pathway and L-malate transport pathway of Aspergillus oryzae for overproduction of L-malate.

Science.gov (United States)

Liu, Jingjing; Xie, Zhipeng; Shin, Hyun-Dong; Li, Jianghua; Du, Guocheng; Chen, Jian; Liu, Long

2017-07-10

Aspergillus oryzae finds wide application in the food, feed, and wine industries, and is an excellent cell factory platform for production of organic acids. In this work, we achieved the overproduction of L-malate by rewiring the reductive tricarboxylic acid (rTCA) pathway and L-malate transport pathway of A. oryzae NRRL 3488. First, overexpression of native pyruvate carboxylase and malate dehydrogenase in the rTCA pathway improved the L-malate titer from 26.1gL -1 to 42.3gL -1 in shake flask culture. Then, the oxaloacetate anaplerotic reaction was constructed by heterologous expression of phosphoenolpyruvate carboxykinase and phosphoenolpyruvate carboxylase from Escherichia coli, increasing the L-malate titer to 58.5gL -1 . Next, the export of L-malate from the cytoplasm to the external medium was strengthened by overexpression of a C4-dicarboxylate transporter gene from A. oryzae and an L-malate permease gene from Schizosaccharomyces pombe, improving the L-malate titer from 58.5gL -1 to 89.5gL -1 . Lastly, guided by transcription analysis of the expression profile of key genes related to L-malate synthesis, the 6-phosphofructokinase encoded by the pfk gene was identified as a potential limiting step for L-malate synthesis. Overexpression of pfk with the strong sodM promoter increased the L-malate titer to 93.2gL -1 . The final engineered A. oryzae strain produced 165gL -1 L-malate with a productivity of 1.38gL -1 h -1 in 3-L fed-batch culture. Overall, we constructed an efficient L-malate producer by rewiring the rTCA pathway and L-malate transport pathway of A. oryzae NRRL 3488, and the engineering strategy adopted here may be useful for the construction of A. oryzae cell factories to produce other organic acids. Copyright © 2017 Elsevier B.V. All rights reserved.

Purine restriction induces pronounced translational upregulation of the NT1 adenosine/pyrimidine nucleoside transporter in Leishmania major.

Science.gov (United States)

Ortiz, Diana; Valdés, Raquel; Sanchez, Marco A; Hayenga, Johanna; Elya, Carolyn; Detke, Siegfried; Landfear, Scott M

2010-10-01

Leishmania and other parasitic protozoa are unable to synthesize purines de novo and are reliant upon purine nucleoside and nucleobase transporters to import preformed purines from their hosts. To study the roles of the four purine permeases NT1-NT4 in Leishmania major, null mutants in each transporter gene were prepared and the effect of each gene deletion on purine uptake was monitored. Deletion of the NT3 purine nucleobase transporter gene or both NT3 and the NT2 nucleoside transporter gene resulted in pronounced upregulation of adenosine and uridine uptake mediated by the NT1 permease and also induced up to a 200-fold enhancement in the level of the NT1 protein but not mRNA. A similar level of upregulation of NT1 was achieved in wild-type promastigotes that were transferred to medium deficient in purines. Pulse labelling and treatment of cells with the translation inhibitor cycloheximide revealed that control of NT1 expression occurs primarily at the level of translation and not protein turnover. These observations imply the existence of a translational control mechanism that enhances the ability of Leishmania parasites to import essential purines when they are present at limiting concentrations. © 2010 Blackwell Publishing Ltd.

Interactive Effects of Jasmonic Acid, Salicylic Acid, and Gibberellin on Induction of Trichomes in Arabidopsis1

Science.gov (United States)

Traw, M. Brian; Bergelson, Joy

2003-01-01

Leaf trichomes protect plants from attack by insect herbivores and are often induced following damage. Hormonal regulation of this plant induction response has not been previously studied. In a series of experiments, we addressed the effects of artificial damage, jasmonic acid, salicylic acid, and gibberellin on induction of trichomes in Arabidopsis. Artificial damage and jasmonic acid caused significant increases in trichome production of leaves. The jar1-1 mutant exhibited normal trichome induction following treatment with jasmonic acid, suggesting that adenylation of jasmonic acid is not necessary. Salicylic acid had a negative effect on trichome production and consistently reduced the effect of jasmonic acid, suggesting negative cross-talk between the jasmonate and salicylate-dependent defense pathways. Interestingly, the effect of salicylic acid persisted in the nim1-1 mutant, suggesting that the Npr1/Nim1 gene is not downstream of salicylic acid in the negative regulation of trichome production. Last, we found that gibberellin and jasmonic acid had a synergistic effect on the induction of trichomes, suggesting important interactions between these two compounds. PMID:14551332

Amino acid derived 1,4-dialkyl substituted imidazolones

DEFF Research Database (Denmark)

Diness, Frederik; Meldal, Morten Peter

2010-01-01

A general method for synthesis of 1,4-substituted imidazolones from amino acids on solid support or in solution has been developed. Amino acid derived 3-Boc-(1,3)-oxazinane (Box) protected amino aldehyde building blocks were coupled through urea bonds to the amino terminal of dipeptides or amino...... acids. Upon acidic release, the aldehyde instantaneously formed the cyclic N-carbamyliminium ion, which rearranged to the corresponding imidazolone. Under strongly acidic conditions the imidazolones acted as nuclophiles in the Pictet-Spengler reaction....

Synthesis of copper quantum dots by chemical reduction method and tailoring of its band gap

Directory of Open Access Journals (Sweden)

P. G. Prabhash

2016-05-01

Full Text Available Metallic copper nano particles are synthesized with citric acid and CTAB (cetyltrimethylammonium bromide as surfactant and chlorides as precursors. The particle size and surface morphology are analyzed by High Resolution Transmission Electron Microscopy. The average size of the nano particle is found to be 3 - 10 nm. The optical absorption characteristics are done by UV-Visible spectrophotometer. From the Tauc plots, the energy band gaps are calculated and because of their smaller size the particles have much higher band gap than the bulk material. The energy band gap is changed from 3.67 eV to 4.27 eV in citric acid coated copper quantum dots and 4.17 eV to 4.52 eV in CTAB coated copper quantum dots.

The prototype GAPS (pGAPS) experiment

International Nuclear Information System (INIS)

Mognet, S.A.I.; Aramaki, T.; Bando, N.; Boggs, S.E.; Doetinchem, P. von; Fuke, H.; Gahbauer, F.H.; Hailey, C.J.; Koglin, J.E.; Madden, N.; Mori, K.; Okazaki, S.; Ong, R.A.; Perez, K.M.; Tajiri, G.; Yoshida, T.; Zweerink, J.

2014-01-01

The General Antiparticle Spectrometer (GAPS) experiment is a novel approach for the detection of cosmic ray antiparticles. A prototype GAPS (pGAPS) experiment was successfully flown on a high-altitude balloon in June of 2012. The goals of the pGAPS experiment were: to test the operation of lithium drifted silicon (Si(Li)) detectors at balloon altitudes, to validate the thermal model and cooling concept needed for engineering of a full-size GAPS instrument, and to characterize cosmic ray and X-ray backgrounds. The instrument was launched from the Japan Aerospace Exploration Agency's (JAXA) Taiki Aerospace Research Field in Hokkaido, Japan. The flight lasted a total of 6 h, with over 3 h at float altitude (∼33km). Over one million cosmic ray triggers were recorded and all flight goals were met or exceeded

Studies on radiolysis of amino acids, 1

International Nuclear Information System (INIS)

Oku, Tadatake

1977-01-01

In order to elucidate the radiolysis of amino acid, peptide, protein and enzyme, the radiolytic mechanisms of neutral amino acids (glycine, L-alanine, L-valine, L-leucine, L-isoleucine, L-serine, and L-threonine) and acidic amino acids (L-aspartic acid, L-glutamic acid and DL-amino-n-adipic acid) were studied in the presence of air or in the atmosphere nitrogen. An aqueous solution of 1 mM. of each amino acid was sealed in a glass ampoule under air or nitrogen. Irradiation of amino acid solutions was carried out with γ-rays of 60 Co at doses of 4.4-2,640x10 3 rads. The amino acids and the radiolytic products formed were determined by ion-exchange chromatography. From the results of determining amino acids and the radiolytic products formed and their G-values, the radiolytic mechanisms of the amino acids were discussed. (auth.)

Modification on ursodeoxycholic acid (UDCA) scaffold. discovery of bile acid derivatives as selective agonists of cell-surface G-protein coupled bile acid receptor 1 (GP-BAR1).

Science.gov (United States)

Sepe, Valentina; Renga, Barbara; Festa, Carmen; D'Amore, Claudio; Masullo, Dario; Cipriani, Sabrina; Di Leva, Francesco Saverio; Monti, Maria Chiara; Novellino, Ettore; Limongelli, Vittorio; Zampella, Angela; Fiorucci, Stefano

2014-09-25

Bile acids are signaling molecules interacting with the nuclear receptor FXR and the G-protein coupled receptor 1 (GP-BAR1/TGR5). GP-BAR1 is a promising pharmacological target for the treatment of steatohepatitis, type 2 diabetes, and obesity. Endogenous bile acids and currently available semisynthetic bile acids are poorly selective toward GP-BAR1 and FXR. Thus, in the present study we have investigated around the structure of UDCA, a clinically used bile acid devoid of FXR agonist activity, to develop a large family of side chain modified 3α,7β-dihydroxyl cholanoids that selectively activate GP-BAR1. In vivo and in vitro pharmacological evaluation demonstrated that administration of compound 16 selectively increases the expression of pro-glucagon 1, a GP-BAR1 target, in the small intestine, while it had no effect on FXR target genes in the liver. Further, compound 16 results in a significant reshaping of bile acid pool in a rodent model of cholestasis. These data demonstrate that UDCA is a useful scaffold to generate novel and selective steroidal ligands for GP-BAR1.

Gap junctions and inhibitory synapses modulate inspiratory motoneuron synchronization.

Science.gov (United States)

Bou-Flores, C; Berger, A J

2001-04-01

Interneuronal electrical coupling via gap junctions and chemical synaptic inhibitory transmission are known to have roles in the generation and synchronization of activity in neuronal networks. Uncertainty exists regarding the roles of these two modes of interneuronal communication in the central respiratory rhythm-generating system. To assess their roles, we performed studies on both the neonatal mouse medullary slice and en bloc brain stem-spinal cord preparations where rhythmic inspiratory motor activity can readily be recorded from both hypoglossal and phrenic nerve roots. The rhythmic inspiratory activity observed had two temporal characteristics: the basic respiratory frequency occurring on a long time scale and the synchronous neuronal discharge within the inspiratory burst occurring on a short time scale. In both preparations, we observed that bath application of gap-junction blockers, including 18 alpha-glycyrrhetinic acid, 18 beta-glycyrrhetinic acid, and carbenoxolone, all caused a reduction in respiratory frequency. In contrast, peak integrated phrenic and hypoglossal inspiratory activity was not significantly changed by gap-junction blockade. On a short-time-scale, gap-junction blockade increased the degree of synchronization within an inspiratory burst observed in both nerves. In contrast, opposite results were observed with blockade of GABA(A) and glycine receptors. We found that respiratory frequency increased with receptor blockade, and simultaneous blockade of both receptors consistently resulted in a reduction in short-time-scale synchronized activity observed in phrenic and hypoglossal inspiratory bursts. These results support the concept that the central respiratory system has two components: a rhythm generator responsible for the production of respiratory cycle timing and an inspiratory pattern generator that is involved in short-time-scale synchronization. In the neonatal rodent, properties of both components can be regulated by interneuronal

Dicty_cDB: Contig-U16457-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U16457-1 no gap 1065 3 996438 997502 PLUS 6 5 U16457 0 0 1 0 1 0 2 0 0 0 0 0 1 1 Show Contig...-U16457-1 Contig ID Contig-U16457-1 Contig update 2004. 6.11 Contig sequence >Contig-U16457-1 (Contig...-U16457-1Q) /CSM_Contig/Contig-U16457-1Q.Seq.d ACAATTGGTGTTGCTGCTCTATTCGGTCTTCCAGCTATGGCACGTTCCGC A...TTTAACAAGATTGGAAGAC CAAAAAGAAAAAAAA Gap no gap Contig length 1065 Chromosome numb... Translated Amino Acid sequence TIGVAALFGLPAMARSAAMSLVFLIPFMWIVFSVHYPINSVVADICMSYNNNTGSIEQQL ANYTNPIVSEIFGTC

CdS{sub x}Te{sub 1-x} ternary semiconductors band gaps calculation using ground state and GW approximations

Energy Technology Data Exchange (ETDEWEB)

Kheloufi, Nawal; Bouzid, Abderrazak, E-mail: a_bouzid34@hotmail.com

2016-06-25

We present band gap calculations of zinc-blende ternary CdS{sub x}Te{sub 1-x} semiconductors within the standard DFT and quasiparticle calculations employing pseudopotential method. The DFT, the local density approximation (LDA) and the Generalized Gradient Approximation (GGA) based calculations have given very poor results compared to experimental data. The quasiparticle calculations have been investigated via the one-shot GW approximation. The present paper discuses and confirms the effect of inclusion of the semicore states in the cadmium (Cd) pseudopotential. The obtained GW quasiparticle band gap using Cd{sup +20} pseudopotential has been improved compared to the obtained results from the available pseudopotential without the treatment of semicore states. Our DFT and quasiparticle band gap results are discussed and compared to the available theoretical calculations and experimental data. - Graphical abstract: Band gaps improvement concerning the binary and ternary alloys using the GW approximation and Cd{sup 20+} pseudopotential with others levels of approximations (the LDA and GGA approximation employing the Cd{sup 12+} and the LDA within Cd{sup 20+} pseudopotential). - Highlights: • The direct Γ- Γ and indirect Γ- X and Γ- L bands gaps show a nonlinear behavior when S content is enhanced. • The quasiparticle band gap result for the investigated semiconductors is improved using the GW approximation. • All CdS{sub x}Te{sub 1-x} compounds in all compositions range from 0 to 1 are direct band gap semiconductors.

Cellular Interaction of Integrin α3β1 with Laminin 5 Promotes Gap Junctional Communication

Science.gov (United States)

Lampe, Paul D.; Nguyen, Beth P.; Gil, Susana; Usui, Marcia; Olerud, John; Takada, Yoshikazu; Carter, William G.

1998-01-01

Wounding of skin activates epidermal cell migration over exposed dermal collagen and fibronectin and over laminin 5 secreted into the provisional basement membrane. Gap junctional intercellular communication (GJIC) has been proposed to integrate the individual motile cells into a synchronized colony. We found that outgrowths of human keratinocytes in wounds or epibole cultures display parallel changes in the expression of laminin 5, integrin α3β1, E-cadherin, and the gap junctional protein connexin 43. Adhesion of keratinocytes on laminin 5, collagen, and fibronectin was found to differentially regulate GJIC. When keratinocytes were adhered on laminin 5, both structural (assembly of connexin 43 in gap junctions) and functional (dye transfer) assays showed a two- to threefold increase compared with collagen and five- to eightfold over fibronectin. Based on studies with immobilized integrin antibody and integrin-transfected Chinese hamster ovary cells, the interaction of integrin α3β1 with laminin 5 was sufficient to promote GJIC. Mapping of intermediate steps in the pathway linking α3β1–laminin 5 interactions to GJIC indicated that protein trafficking and Rho signaling were both required. We suggest that adhesion of epithelial cells to laminin 5 in the basement membrane via α3β1 promotes GJIC that integrates individual cells into synchronized epiboles. PMID:9852164

Dicty_cDB: Contig-U13326-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U13326-1 no gap 240 6 1728259 1728019 MINUS 1 1 U13326 0 0 0 0 0 1 0 0 0 0 0 0 0 0 Show Contig...-U13326-1 Contig ID Contig-U13326-1 Contig update 2002.12.18 Contig sequence >Contig-U13326-1 (Contig...-U13326-1Q) /CSM_Contig/Contig-U13326-1Q.Seq.d AATGACTCAACAAATCTTGGAGAGTATGCAAAATACTTTCCAATCTATGG...CCTCGTTAAAGGTGCTGGTGC TGAATTAAGTTCTCGTGCTCATGAGTGTTTCATTAGTGCCTTGGATATTG CCTCTGATTATACCTACGAGAAAATTACCATTGGCTTGGA Gap no gap Contig...FQSMDGPTIKRLATTIQYGSKDVDEQQIHSTLVKGAGAELSSRAHECF ISALDIASDYTYEKITIGL Translated Amino Acid sequence (All Fra

Density functional theory design D-D-A type small molecule with 1.03 eV narrow band gap: effect of electron donor unit for organic photovoltaic solar cell

Science.gov (United States)

Sıdır, İsa

2017-10-01

Six new low-band-gap copolymers of donor-donor-acceptor (D-D-A) architecture have been designed using density functional theory and time-dependent density functional theory methods in order to use them in organic photovoltaic cell (OPVC). Phenanthro[3,4-d:9,10-d‧]bis([1,2,3]thiadiazole)-10,12-dicarbonitrile moiety has been used as an acceptor for all compounds. We insert benzo[1,2-b:4,5-b‧]dithiophene and N,N-diphenylbenzo[1,2-b:4,5-b‧]dithiophen-2-amine units as donor to complete designing of copolymers. In order to tuning the optical and electronic properties, we have modified the donor unit by substituted with amine, methoxyamine, N-methylenethiophen-2-amine, methoxy, alkoxy moieties. The band gap (Eg), HOMO and LUMO values and plots, open circuit voltage (VOC) as well as optical properties have been analysed for designed copolymers. The optimised copolymers exhibit low-band-gap lying in the range of 1.03-2.24 eV. DPTD-6 copolymer presents the optimal properties to be used as an active layer due to its low Eg (1.03 eV) and a moderate VOC (0.56 eV). Thus, OPVC based on this copolymer in bulk-heterojunction composites with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as an acceptor has been modelled. Eg and VOC values of composite material DPTD-6:PCBM are found as 1.32 and 0.65 eV, respectively. A model band diagram has been established for OPVC, simulating the energy transfer between active layers.

Transport Deficiency Is the Molecular Basis of Candida albicans Resistance to Antifungal Oligopeptides

Directory of Open Access Journals (Sweden)

Marta Schielmann

2017-11-01

Full Text Available Oligopeptides incorporating N3-(4-methoxyfumaroyl-L-2,3-diaminopropanoic acid (FMDP, an inhibitor of glucosamine-6-phosphate synthase, exhibited growth inhibitory activity against Candida albicans, with minimal inhibitory concentration values in the 0.05–50 μg mL-1 range. Uptake by the peptide permeases was found to be the main factor limiting an anticandidal activity of these compounds. Di- and tripeptide containing FMDP (F2 and F3 were transported by Ptr2p/Ptr22p peptide transporters (PTR and FMDP-containing hexa-, hepta-, and undecapeptide (F6, F7, and F11 were taken up by the oligopeptide transporters (OPT oligopeptide permeases, preferably by Opt2p/Opt3p. A phenotypic, apparent resistance of C. albicans to FMDP-oligopeptides transported by OPT permeases was triggered by the environmental factors, whereas resistance to those taken up by the PTR system had a genetic basis. Anticandidal activity of longer FMDP-oligopeptides was strongly diminished in minimal media containing easily assimilated ammonium sulfate or L-glutamine as the nitrogen source, both known to downregulate expression of the OPT genes. All FMDP-oligopeptides tested were more active at lower pH and this effect was slightly more remarkable for peptides F6, F7, and F11, compared to F2 and F3. Formation of isolated colonies was observed inside the growth inhibitory zones induced by F2 and F3 but not inside those induced by F6, F7, and F11. The vast majority (98% of those colonies did not originate from truly resistant cells. The true resistance of 2% of isolates was due to the impaired transport of di- and to a lower extent, tripeptides. The resistant cells did not exhibit a lower expression of PTR2, PTR22, or OPT1–3 genes, but mutations in the PTR2 gene resulting in T422H, A320S, D119V, and A320S substitutions in the amino acid sequence of Ptr2p were found.

The prototype GAPS (pGAPS) experiment

Energy Technology Data Exchange (ETDEWEB)

Mognet, S.A.I., E-mail: mognet@astro.ucla.edu [University of California, Los Angeles, CA 90095 (United States); Aramaki, T. [Columbia University, New York, NY 10027 (United States); Bando, N. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Boggs, S.E.; Doetinchem, P. von [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Fuke, H. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Gahbauer, F.H.; Hailey, C.J.; Koglin, J.E.; Madden, N. [Columbia University, New York, NY 10027 (United States); Mori, K.; Okazaki, S. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Ong, R.A. [University of California, Los Angeles, CA 90095 (United States); Perez, K.M.; Tajiri, G. [Columbia University, New York, NY 10027 (United States); Yoshida, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Zweerink, J. [University of California, Los Angeles, CA 90095 (United States)

2014-01-21

The General Antiparticle Spectrometer (GAPS) experiment is a novel approach for the detection of cosmic ray antiparticles. A prototype GAPS (pGAPS) experiment was successfully flown on a high-altitude balloon in June of 2012. The goals of the pGAPS experiment were: to test the operation of lithium drifted silicon (Si(Li)) detectors at balloon altitudes, to validate the thermal model and cooling concept needed for engineering of a full-size GAPS instrument, and to characterize cosmic ray and X-ray backgrounds. The instrument was launched from the Japan Aerospace Exploration Agency's (JAXA) Taiki Aerospace Research Field in Hokkaido, Japan. The flight lasted a total of 6 h, with over 3 h at float altitude (∼33km). Over one million cosmic ray triggers were recorded and all flight goals were met or exceeded.

Fatty Acids are Key in 4-Hydroxy-2-Nonenal-Mediated Activation of Uncoupling Proteins 1 and 2

Czech Academy of Sciences Publication Activity Database

Malingriaux, E. A.; Rupprecht, A.; Gille, L.; Jovanovic, O.; Ježek, Petr; Jabůrek, Martin; Pohl, E. E.

2013-01-01

Roč. 8, č. 10 (2013), e77786 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GAP302/10/0346 Institutional support: RVO:67985823 Keywords : mitochondrial uncoupling proteins * 4-hydroxy-2-nonenal * fatty acids Subject RIV: EA - Cell Biology Impact factor: 3.534, year: 2013

The Arabidopsis pi4kIIIβ1β2 double mutant is salicylic acid-overaccumulating: A new example of salicylic acid influence on plant stature

Czech Academy of Sciences Publication Activity Database

Janda, Martin; Šašek, Vladimír; Ruelland, E.

2014-01-01

Roč. 9, č. 12 (2014) ISSN 1559-2324 R&D Projects: GA ČR(CZ) GAP501/11/1654 Institutional support: RVO:61389030 Keywords : phosphatidylinositol-4-kinase * plant growth * salicylic acid Subject RIV: ED - Physiology http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=MEDLINE&DestLinkType=FullRecord&UT=25482755

Low band gap frequencies and multiplexing properties in 1D and 2D mass spring structures

International Nuclear Information System (INIS)

Aly, Arafa H; Mehaney, Ahmed

2016-01-01

This study reports on the propagation of elastic waves in 1D and 2D mass spring structures. An analytical and computation model is presented for the 1D and 2D mass spring systems with different examples. An enhancement in the band gap values was obtained by modeling the structures to obtain low frequency band gaps at small dimensions. Additionally, the evolution of the band gap as a function of mass value is discussed. Special attention is devoted to the local resonance property in frequency ranges within the gaps in the band structure for the corresponding infinite periodic lattice in the 1D and 2D mass spring system. A linear defect formed of a row of specific masses produces an elastic waveguide that transmits at the narrow pass band frequency. The frequency of the waveguides can be selected by adjusting the mass and stiffness coefficients of the materials constituting the waveguide. Moreover, we pay more attention to analyze the wave multiplexer and DE-multiplexer in the 2D mass spring system. We show that two of these tunable waveguides with alternating materials can be employed to filter and separate specific frequencies from a broad band input signal. The presented simulation data is validated through comparison with the published research, and can be extended in the development of resonators and MEMS verification. (paper)

Determination of strong ion gap in healthy dogs.

Science.gov (United States)

Fettig, Pamela K; Bailey, Dennis B; Gannon, Kristi M

2012-08-01

To determine and compare reference intervals of the strong ion gap (SIG) in a group of healthy dogs determined with 2 different equations. Prospective observational study. Tertiary referral and teaching hospital. Fifty-four healthy dogs. None. Serum biochemistry and blood gas analyses were performed for each dog. From these values, SIG was calculated using 2 different equations: SIG(1) = SID(a) {[Na (+)] + [K(+)] - [Cl(-)]+ [2 × Ca(2+)] + [2 × Mg(2+)] - [L-lactate]}- SID(e) {TCO(2) + A(-)} and SIG(2) = [albumin] × 4.9-anion gap. Reference intervals were established for each SIG equation using the mean ± 1.96 × standard deviation (SD). For SIG(1), the median was 7.13 mEq/L (range, 1.05-11.30 mEq/L) and the derived reference interval was 1.85-10.61 mEq/L. Median SIG(2) was -0.22 mEq/L (range, -5.34-6.61 mEq/L) and the mean SIG(2) was -0.09 mEq/L (95% confidence interval for the mean, -0.82-0.65 mEq/L). The derived reference interval was -5.36-5.18 mEq/L. The results of the SIG calculations were significantly different (P SIG yielded significantly different results and cannot be used interchangeably. The authors believe SIG(2) to be a more accurate reflection of acid-base status in healthy dogs, and recommend that this calculation be used for future studies. © Veterinary Emergency and Critical Care Society 2012.

Gap junctional communication modulates gene transcription by altering the recruitment of Sp1 and Sp3 to connexin-response elements in osteoblast promoters

Science.gov (United States)

Stains, Joseph P.; Lecanda, Fernando; Screen, Joanne; Towler, Dwight A.; Civitelli, Roberto

2003-01-01

Loss-of-function mutations of gap junction proteins, connexins, represent a mechanism of disease in a variety of tissues. We have shown that recessive (gene deletion) or dominant (connexin45 overexpression) disruption of connexin43 function results in osteoblast dysfunction and abnormal expression of osteoblast genes, including down-regulation of osteocalcin transcription. To elucidate the molecular mechanisms of gap junction-sensitive transcriptional regulation, we systematically analyzed the rat osteocalcin promoter for sensitivity to gap junctional intercellular communication. We identified an Sp1/Sp3 containing complex that assembles on a minimal element in the -70 to -57 region of the osteocalcin promoter in a gap junction-dependent manner. This CT-rich connexin-response element is necessary and sufficient to confer gap junction sensitivity to the osteocalcin proximal promoter. Repression of osteocalcin transcription occurs as a result of displacement of the stimulatory Sp1 by the inhibitory Sp3 on the promoter when gap junctional communication is perturbed. Modulation of Sp1/Sp3 recruitment also occurs on the collagen Ialpha1 promoter and translates into gap junction-sensitive transcriptional control of collagen Ialpha1 gene expression. Thus, regulation of Sp1/Sp3 recruitment to the promoter may represent a potential general mechanism for transcriptional control of target genes by signals passing through gap junctions.

Dicty_cDB: Contig-U16467-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U16467-1 no gap 1261 2 7818565 7817305 MINUS 17 18 U16467 0 0 5 0 1 2 1 0 6 0 0 1 1 0 Show Contig...-U16467-1 Contig ID Contig-U16467-1 Contig update 2004. 6.11 Contig sequence >Contig-U16467-1 (Contig...-U16467-1Q) /CSM_Contig/Contig-U16467-1Q.Seq.d CAACAATTAACATTACTTAAATATAATATTATTATATTTTTTTTTTT...TTCAAATAAATAATTGTTTAGAAATTTCTAGAAAAAAAA AAAAAAAAAAA Gap no gap Contig length 1261 Chromosome number (1..6, M...LK833Z ,1005,1249 Translated Amino Acid sequence qqltllkyniiiffffyllplhlyhy**LKKKTLTIIKYFFQKMNKIALLFTIFFALFAI SFACDEFNPNTSTIG

Dicty_cDB: Contig-U09581-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U09581-1 gap included 1235 1 2575525 2576764 PLUS 1 2 U09581 0 0 1 0 0 0 0 0 0 0 0 0 0 0 Show Contig...-U09581-1 Contig ID Contig-U09581-1 Contig update 2002. 9.13 Contig sequence >Contig-U09581-1 (Contig-U09581-1Q) /CSM_Contig/Contig-U09581...ATCAAAATAAATTTTTGTAACATTAATAATAAATAAN Gap gap included Contig length 1235 Chromosome number (1..6, M) 1 Chro... VFD420Z ,579,1237 Translated Amino Acid sequence KKPGVVTIKGSSFCSQPTITIGDDSCSQPILSVGNDYDSLTCNFQSNAGLSNSTLLVS...ames) Frame A: KKPGVVTIKGSSFCSQPTITIGDDSCSQPILSVGNDYDSLTCNFQSNAGLSNSTLLVSII CDTIQ

Dicty_cDB: Contig-U04729-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U04729-1 no gap 251 5 1037629 1037880 PLUS 1 1 U04729 0 0 0 0 0 0 1 0 0 0 0 0 0 0 Show Contig...-U04729-1 Contig ID Contig-U04729-1 Contig update 2001. 8.29 Contig sequence >Contig-U04729-1 (Contig...-U04729-1Q) /CSM_Contig/Contig-U04729-1Q.Seq.d TGGATTTATAACAGAGGTTATTGTAGGTGGTAAAACTTTTAGAGGAATCG ...CATTATCTAATGGG T Gap no gap Contig length 251 Chromosome number (1..6, M) 5 Chromosome length 5062330 Start ...ITEVIVGGKTFRGIVFEDLKSSNQTNNHSQNFSPNQSGTNLNNSNSNIPSSKKIKDKN ISPSSFLPTIGSTTSTSNPLSNG Translated Amino Acid seq

Fabrication of bioactive conduits containing the fibroblast growth factor 1 and neural stem cells for peripheral nerve regeneration across a 15 mm critical gap

International Nuclear Information System (INIS)

Ni, Hsiao-Chiang; Tseng, Ting-Chen; Hsu, Shan-hui; Chen, Jeng-Rung; Chiu, Ing-Ming

2013-01-01

Nerve conduits are often used in combination with bioactive molecules and stem cells to enhance peripheral nerve regeneration. In this study, the acidic fibroblast growth factor 1 (FGF1) was immobilized onto the microporous/micropatterned poly (D, L-lactic acid) (PLA) nerve conduits after open air plasma treatment. PLA substrates grafted with chitosan in the presence of a small amount of gold nanoparticles (nano Au) showed a protective effect on the activity of the immobilized FGF1 in vitro. Different conduits were tested for their ability to bridge a 15 mm critical gap defect in a rat sciatic nerve injury model. Axon regeneration and functional recovery were evaluated by histology, walking track analysis and electrophysiology. Among different conduits, PLA conduits grafted with chitosan–nano Au and the FGF1 after plasma activation had the greatest regeneration capacity and functional recovery in the experimental animals. When the above conduit was seeded with aligned neural stem cells, the efficacy was further enhanced and it approached that of the autograft group. This work suggested that microporous/micropatterned nerve conduits containing bioactive growth factors may be successfully fabricated by micropatterning techniques, open plasma activation, and immobilization, which, combined with aligned stem cells, may synergistically contribute to the regeneration of the severely damaged peripheral nerve. (paper)

Bacteriophage GC1, a Novel Tectivirus Infecting Gluconobacter Cerinus, an Acetic Acid Bacterium Associated with Wine-Making

Directory of Open Access Journals (Sweden)

Cécile Philippe

2018-01-01

Full Text Available The Gluconobacter phage GC1 is a novel member of the Tectiviridae family isolated from a juice sample collected during dry white wine making. The bacteriophage infects Gluconobacter cerinus, an acetic acid bacterium which represents a spoilage microorganism during wine making, mainly because it is able to produce ethyl alcohol and transform it into acetic acid. Transmission electron microscopy revealed tail-less icosahedral particles with a diameter of ~78 nm. The linear double-stranded DNA genome of GC1 (16,523 base pairs contains terminal inverted repeats and carries 36 open reading frames, only a handful of which could be functionally annotated. These encode for the key proteins involved in DNA replication (protein-primed family B DNA polymerase as well as in virion structure and assembly (major capsid protein, genome packaging ATPase (adenosine triphosphatase and several minor capsid proteins. GC1 is the first tectivirus infecting an alphaproteobacterial host and is thus far the only temperate tectivirus of gram-negative bacteria. Based on distinctive sequence and life-style features, we propose that GC1 represents a new genus within the Tectiviridae, which we tentatively named “Gammatectivirus”. Furthermore, GC1 helps to bridge the gap in the sequence space between alphatectiviruses and betatectiviruses.

Identification and functional characterization of the Lactococcus lactis CodY-regulated branched-chain amino acid permease BcaP (CtrA)

NARCIS (Netherlands)

den Hengst, CD; Groeneveld, M; Kuipers, OP; Kok, J; Hengst, Chris D. den

Transcriptome analyses have previously revealed that a gene encoding the putative amino acid transporter CtrA (YhdG) is one of the major targets of the pleiotropic regulator CodY in Lactococcus lactis and Bacillus subtilis. The role of ctrA in L. lactis was further investigated with respect to both

Dicty_cDB: Contig-U11706-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available one) Shewanella baltica OS195, complet... 37 1.1 AJ875406_1( AJ875406 |pid:none) Candida intermedia mRNA for...none) Leishmania major strain Friedlin... 35 4.3 AD2736( AD2736 ) MFS permease [imported] - Agrobacterium tumefacie..... 36 3.0 8 ( ER451042 ) 1092963849549 Global-Ocean-Sampling_GS-35-01-01-1... 34 3.2 3 ( AC115626 ) Homo sapie...J956921 ) 1093018976377 Global-Ocean-Sampling_GS-30-02-01-1... 38 0.13 2 ( EJ412209 ) 1093012157126 Global-Ocean-Sampli...6 0.33 2 ( EK421366 ) 1095515508395 Global-Ocean-Sampling_GS-31-01-01-1... 42 0.48 2 ( AM430719 ) Vitis vini

Chemoselective synthesis of sialic acid 1,7-lactones.

Science.gov (United States)

Allevi, Pietro; Rota, Paola; Scaringi, Raffaella; Colombo, Raffaele; Anastasia, Mario

2010-08-20

The chemoselective synthesis of the 1,7-lactones of N-acetylneuraminic acid, N-glycolylneuraminic acid, and 3-deoxy-d-glycero-d-galacto-nononic acid is accomplished in two steps: a simple treatment of the corresponding free sialic acid with benzyloxycarbonyl chloride and a successive hydrogenolysis of the formed 2-benzyloxycarbonyl 1,7-lactone. The instability of the 1,7-lactones to protic solvents has been also evidenced together with the rationalization of the mechanism of their formation under acylation conditions. The results permit to dispose of authentic 1,7-sialolactones to be used as reference standards and of a procedure useful for the preparation of their isotopologues to be used as inner standards in improved analytical procedures for the gas liquid chromatography-mass spectrometry (GLC-MS) analysis of 1,7-sialolactones in biological media.

Band gap and mobility of epitaxial perovskite BaSn1 -xHfxO3 thin films

Science.gov (United States)

Shin, Juyeon; Lim, Jinyoung; Ha, Taewoo; Kim, Young Mo; Park, Chulkwon; Yu, Jaejun; Kim, Jae Hoon; Char, Kookrin

2018-02-01

A wide band-gap perovskite oxide BaSn O3 is attracting much attention due to its high electron mobility and oxygen stability. On the other hand, BaHf O3 was recently reported to be an effective high-k gate oxide. Here, we investigate the band gap and mobility of solid solutions of BaS n1 -xH fxO3 (x =0 -1 ) (BSHO) as a basis to build advanced perovskite oxide heterostructures. All the films were epitaxially grown on MgO substrates using pulsed laser deposition. Density functional theory calculations confirmed that Hf substitution does not create midgap states while increasing the band gap. From x-ray diffraction and optical transmittance measurements, the lattice constants and the band-gap values are significantly modified by Hf substitution. We also measured the transport properties of n -type La-doped BSHO films [(Ba ,La ) (Sn ,Hf ) O3 ] , investigating the feasibility of modulation doping in the BaSn O3/BSHO heterostructures. The Hall measurement data revealed that, as the Hf content increases, the activation rate of the La dopant decreases and the scattering rate of the electrons sharply increases. These properties of BSHO films may be useful for applications in various heterostructures based on the BaSn O3 system.

On the Feasibility of Gap Detection of Power Transformer Partial Discharge UHF Signals: Gap Propagation Characteristics of Electromagnetic Waves

OpenAIRE

Xiaoxing Zhang; Guozhi Zhang; Yalong Li; Jian Zhang; Rui Huang

2017-01-01

This study analyzed the transformer electromagnetic gap propagation characteristics. The influence of gap size is also analyzed, and the results experimentally verified. The obtained results indicated that the gap propagation characteristics of electromagnetic wave signals radiated by the partial discharge (PD) source in different directions are substantially different. The intensity of the electromagnetic wave in the gap reaches a maximum at a gap height of 1 cm; and inside the gap, the inte...

Comparative in vitro metabolism of 1-14C-oleic acid and 1-14C-erucic acid in liver, heart and skeletal muscles of rats

International Nuclear Information System (INIS)

Bhatia, I.S.; Sharma, A.K.; Ahuja, S.P.

1978-01-01

In vitro oxidation of 14 C-oleic and 1- 14 C-erucic acid and their incorporation into lipids by liver, heart and skeletal muscles from female albino rats were studied. These tissues were obtained from rats maintained for 120 days on low fat diet or diets containing 15% mustard oil or 15% groundnut oil. In all these tissues from rats on different types of diets, the oxidation of 1- 14 C-erucic acid was lower than that 1- 14 C-oleic acid. There was little accumulation of lipids in heart after 120 days of feeding mustard oil. Oxidation of 1- 14 C-erucic acid was enhanced in liver, heart and skeletal muscles of rats conditioned to the mustard oil diet supplying erucic acid. Oxidation of erucic acid was maximum in liver and least in heart, whereas there were no differences in the oxidation of 1- 14 C-oleic acid in these tissues. Incorporation of 1- 14 C-oleic acid into triglycerides and phospholipids was not affected by the type of diet or tissues Incorporation of 1- 14 C-erucic acid was mainly into triglycerides of heart and skeletal muscles of rats not accustomed to mustard oil diet whereas these tissues from rats accustomed to mustard oil diets incorporated 1- 14 C-erucic acid both into the triglycerides and phospholipids. (author)

12038_2016_9626_Supplementary 1..3

Indian Academy of Sciences (India)

negatively regulates stress-induced cell death. SUBARAN SINGH, ANUPRIYA SINGH and ASHIS KUMAR NANDI ... of OsSAG12-1 and OssAg12-2 amino acid sequences. Matrix: EBLOSUM62,. Gap_penalty: 10.0, Extend penalty: 0.5, Identity: 161/316 (50.9%, Similarity: 205/316 (64.9%), Gaps: 26/316 (8.2%, Score: 822.5.

Rapidity gaps between jets in p bar p collisions at √s =1.8 TeV

International Nuclear Information System (INIS)

Abachi, S.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adam, I.; Adams, D.L.; Adams, M.; Ahn, S.; Aihara, H.; Alvarez, G.; Alves, G.A.; Amos, N.; Anderson, E.W.; Antipov, Y.; Aronson, S.H.; Astur, R.; Avery, R.E.; Baden, A.; Balamurali, V.; Balderston, J.; Baldin, B.; Bantly, J.; Bartlett, J.F.; Bazizi, K.; Behnke, T.; Bendich, J.; Beri, S.B.; Bezzubov, V.; Bhat, P.C.; Bhatnagar, V.; Biswas, N.; Blazey, G.; Blessing, S.; Boehnlein, A.; Borcherding, F.; Borders, J.; Bozko, N.; Brandt, A.; Brock, R.; Bross, A.; Buchholz, D.; Burtovoi, V.; Butler, J.M.; Callot, O.H.; Castilla-Valdez, H.; Chakraborty, D.; Chekulaev, S.; Chen, J.; Chen, L.; Chen, W.; Chevalier, L.; Chopra, S.; Choudhary, B.C.; Christenson, J.H.; Chung, M.; Claes, D.; Clark, A.R.; Cobau, W.G.; Cochran, J.; Cooper, W.E.; Cretsinger, C.; Cullen-Vidal, D.; Cummings, M.; Cussonneau, J.P.; Cutts, D.; Dahl, O.I.; De, K.; Demarteau, M.; Demina, R.; Denisenko, K.; Denisenko, N.; Denisov, D.; Denisov, S.; Dharmaratna, W.; Diehl, H.T.; Diesburg, M.; Dixon, R.; Draper, P.; Ducros, Y.; Durston-Johnson, S.; Eartly, D.; Edmunds, D.; Efimov, A.; Ellison, J.; Elvira, V.D.; Engelmann, R.; Eppley, G.; Eroshin, O.; Evdokimov, V.; Fahey, S.; Fanourakis, G.; Fatyga, M.; Fatyga, M.K.; Featherly, J.; Feher, S.; Fein, D.; Ferbel, T.; Finocchiaro, G.; Fisk, H.E.; Flattum, E.; Forden, G.E.; Fortner, M.; Franzini, P.; Fredriksen, S.; Fuess, S.; Gao, C.S.; Geld, T.L.; Genser, K.; Gerber, C.E.; Gibbard, B.; Glebov, V.; Glicenstein, J.F.; Gobbi, B.; Goforth, M.; Goldschmidt, M.; Gomez, B.; Good, M.L.; Gordon, H.; Graf, N.; Grannis, P.D.; Green, D.R.; Green, J.; Greenlee, H.; Grossman, N.; Grudberg, P.; Gruenendahl, S.; Guida, J.A.; Guida, J.M.; Guryn, W.; Hadley, N.J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hall, R.E.; Hansen, S.; Hauptman, J.M.; Hedin, D.; Heinson, A.P.; Heintz, U.; Herrera-Corral, G.; Heuring, T.; Hirosky, R.; Hoeneisen, B.; Hoftun, J.S.; Hu, T.; Hubbard, J.R.; Huehn, T.; Igarashi, S.; Ito, A.S.

1994-01-01

First experimental results are presented from a search for events with a rapidity gap between jets. The D0 detector was used to examine events produced by the Fermilab Tevatron p bar p collider at √s =1.8 TeV. The fraction of events with an observed rapidity gap between the two highest transverse energy (E T ) jets is measured as a function of the pseudorapidity separation between the jet edges (Δη c ). An upper limit at the 95% confidence level of 1.1x10 -2 is obtained on the fraction of events with non particles between the jets, for events with Δη c >3 and jet E T greater than 30 GeV

GapBlaster-A Graphical Gap Filler for Prokaryote Genomes.

Directory of Open Access Journals (Sweden)

Pablo H C G de Sá

Full Text Available The advent of NGS (Next Generation Sequencing technologies has resulted in an exponential increase in the number of complete genomes available in biological databases. This advance has allowed the development of several computational tools enabling analyses of large amounts of data in each of the various steps, from processing and quality filtering to gap filling and manual curation. The tools developed for gap closure are very useful as they result in more complete genomes, which will influence downstream analyses of genomic plasticity and comparative genomics. However, the gap filling step remains a challenge for genome assembly, often requiring manual intervention. Here, we present GapBlaster, a graphical application to evaluate and close gaps. GapBlaster was developed via Java programming language. The software uses contigs obtained in the assembly of the genome to perform an alignment against a draft of the genome/scaffold, using BLAST or Mummer to close gaps. Then, all identified alignments of contigs that extend through the gaps in the draft sequence are presented to the user for further evaluation via the GapBlaster graphical interface. GapBlaster presents significant results compared to other similar software and has the advantage of offering a graphical interface for manual curation of the gaps. GapBlaster program, the user guide and the test datasets are freely available at https://sourceforge.net/projects/gapblaster2015/. It requires Sun JDK 8 and Blast or Mummer.

Investigation de l'anisotropie du gap supraconducteur dans les composes Ba(Fe(1-x)Co(x))2As2, Ba(1-x)K(x)Fe2As2, LiFeAs et Fe1-deltaTe(1-x)Se(x)

Science.gov (United States)

Reid, Jean-Philippe

ommaire La structure du gap supraconducteur et sa modulation sont intimement liees au potentiel d'interaction responsable de l'appariement des electrons d'un supraconducteur. Ainsi, l'etude de la structure du gap-SC et de sa modulation permettent de faire la lumiere sur la nature du mecanisme d'appariement des electrons. A cet egard, les resultats experimentaux des supraconducteurs a base de fer ne cadrent pas dans un seul ensemble, ce qui est en opposition au gap-SC universel des cuprates. Dans ce qui suit, nous presenterons une etude systematique du gap-SC pour plusieurs pnictides. En effet, en utilisant la conductivite thermique, une sonde directionnelle du gap-SC, nous avons ete en mesure de reveler la structure du gap-SC pour les composes suivants : Ba1-xKxFe 2As2, Ba(Fe1-xCo x)2As2, LiFeAs et Fe1-deltaTe 1-xSex. L'etude de ces quatre composes, de trois differentes familles structurales, a pu etablir un tableau partiel mais tres exhaustif de la structure du gap-SC de pnictides. En effet, tel qu'illustre dans cette these, ces quatre composes ne possedent aucun noeud dans leur structure du gap-SC a dopage optimal. Toutefois, a une concentration differente de celle optimale pour les composes K-Ba122 et Co-Ba122, des noeuds apparaissent sur la surface de Fermi, aux extremites 'du dome supraconducteur. Ceci suggere fortement que, pour ces composes, la presence de noeuds sur la surface de Fermi est nuisible a la phase supraconductrice. Mots-cles: Supraconducteurs a base de fer, Pnictides, Structure du gap supraconducteur, Conductivite thermique

Gallic Acid Inhibited Matrix Invasion and AP-1/ETS-1-Mediated MMP-1 Transcription in Human Nasopharyngeal Carcinoma Cells.

Science.gov (United States)

Pang, Jong-Hwei S; Yen, Jia-Hau; Wu, Hsiao-Ting; Huang, Sheng-Teng

2017-06-24

Gallic acid is a trihydroxybenzoic acid found in natural herbal plants. Gallic acid has been reported to inhibit the migration and invasive capability of various cancers. Little is known about the underlying mechanisms of invasion responsible for cancer metastasis via gallic acid. The present study was intended to investigate the anti-invasive effect of gallic acid on human nasopharyngeal carcinoma cells (NPC-BM1) and its related mechanism. Gallic acid inhibited the invasion of NPC-BM1 cells dose- and time-dependently without significant cytotoxic effect. Affymetrix oligonucleotide microarray analysis revealed matrix metalloproteinase-1 (MMP-1) as the most down-regulated gene in NPC-BM1 cells by gallic acid. The cytosolic and secreted MMP-1 levels were both found to be inhibited by gallic acid as demonstrated by western blot analysis and ELISA respectively. The mRNA expression and transcription of MMP-1 gene was also down-regulated as determined by RT/real-time PCR and promoter activity assay. The expression of two major transcription binding factors in the MMP-1 promoter, AP-1 and ETS-1, were demonstrated to be reduced by gallic acid in NPC-BM1 cells. The effect of gallic acid was associated with the inhibition of p38 MAPK signaling pathway. In addition, gallic acid enhanced the gene expression of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) which further suppressed the MMP-1 activity. These findings may be useful to develop a novel chemotherapeutic agent to inhibit the metastasis of nasopharyngeal cancer.

Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells.

Science.gov (United States)

Lajczak, Natalia K; Saint-Criq, Vinciane; O'Dwyer, Aoife M; Perino, Alessia; Adorini, Luciano; Schoonjans, Kristina; Keely, Stephen J

2017-09-01

Bile acids and epithelial-derived human β-defensins (HβDs) are known to be important factors in the regulation of colonic mucosal barrier function and inflammation. We hypothesized that bile acids regulate colonic HβD expression and aimed to test this by investigating the effects of deoxycholic acid (DCA) and ursodeoxycholic acid on the expression and release of HβD1 and HβD2 from colonic epithelial cells and mucosal tissues. DCA (10-150 µM) stimulated the release of both HβD1 and HβD2 from epithelial cell monolayers and human colonic mucosal tissue in vitro In contrast, ursodeoxycholic acid (50-200 µM) inhibited both basal and DCA-induced defensin release. Effects of DCA were mimicked by the Takeda GPCR 5 agonist, INT-777 (50 μM), but not by the farnesoid X receptor agonist, GW4064 (10 μM). INT-777 also stimulated colonic HβD1 and HβD2 release from wild-type, but not Takeda GPCR 5 -/- , mice. DCA stimulated phosphorylation of the p65 subunit of NF-κB, an effect that was attenuated by ursodeoxycholic acid, whereas an NF-κB inhibitor, BMS-345541 (25 μM), inhibited DCA-induced HβD2, but not HβD1, release. We conclude that bile acids can differentially regulate colonic epithelial HβD expression and secretion and discuss the implications of our findings for intestinal health and disease.-Lajczak, N. K., Saint-Criq, V., O'Dwyer, A. M., Perino, A., Adorini, L., Schoonjans, K., Keely, S. J. Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells. © FASEB.

Comparison of GAP-3 and GAP-4 experiments with conduction freezing calculations

International Nuclear Information System (INIS)

Sienicki, J.J.; Spencer, B.W.

1983-01-01

Experiments GAP-3 and GAP-4 were performed at ANL to investigate the ability of molten fuel to penetrate downward through the narrow channels separating adjacent subassemblies during an LMFBR hypothetical core disruptive accident. Molten fuel-metal mixtures (81% UO 2 , 19% Mo) at an initial temperature of 3470 0 K generated by a thermite reaction were injected downward into 1 m long rectangular test sections (gap thickness = 0.43 cm, channel width = 20.3 cm) initially at 1170 0 K simulating the nominal Clinch River Breeder Reactor intersubassembly gap. In the GAP-3 test, a prolonged reaction time of approx. 15 s resulted in segregation of the metallic Mo and oxidic UO 2 constituents within the reaction vessel prior to injection. Consequently, Mo entered the test section first and froze, forming a complete plug at a penetration distance of 0.18 m. In GAP-4, the reaction time was reduced to approx. 3 s and the constituents remained well mixed upon injection with the result that the leading edge penetration distance increased to 0.35 m. Posttest examination of the cut-open test sections has revealed the existence of stable insulating crusts upon the underlying steel walls with melting and ablation of the walls only very localized

Possibility of 1-nm level localization of a single molecule with gap-mode surface-enhanced Raman scattering

International Nuclear Information System (INIS)

Choi, Han Kyu; Kim, Zee Hwan

2015-01-01

The electromagnetic (EM) enhancement mechanism of surface-enhanced Raman scattering (SERS) has been well established through 30 years of extensive investigation: molecules adsorbed on resonantly driven silver or gold nanoparticles (NPs) experience strongly enhanced field and thus show enhanced Raman scattering. Even stronger SERS enhancement is possible with a gap structure in which two or more NPs form assemblies with gap sizes of 1 nm or less. We have theoretically shown that the measurement of SERS angular distribution can reveal the position of a single molecule near the gap with 1-nm accuracy, even though the spatial extent of the enhanced field is ~10 nm. Real implementation of such experiment requires extremely well-defined (preferably a single crystal) dimeric junctions. Nevertheless, the experiment will provide spatial as well as frequency domain information on single-molecule dynamics at metallic surfaces

Huge operation by energy gap of novel narrow band gap Tl1-x In1-x B x Se2 (B = Si, Ge): DFT, x-ray emission and photoconductivity studies

Science.gov (United States)

Piasecki, M.; Myronchuk, G. L.; Zamurueva, O. V.; Khyzhun, O. Y.; Parasyuk, O. V.; Fedorchuk, A. O.; Albassam, A.; El-Naggar, A. M.; Kityk, I. V.

2016-02-01

It is shown that narrow band gap semiconductors Tl1-x In1-x GexSe2 are able effectively to vary the values of the energy gap. DFT simulations of the principal bands during the cationic substitutions is done. Changes of carrier transport features is explored. Relation with the changes of the near the surface states is explored . Comparison on a common energy scale of the x-ray emission Se Kβ 2 bands, representing energy distribution of the Se 4p states, indicates that these states contribute preliminary to the top of the valence band. The temperature dependence of electrical conductivity and spectral dependence photoconductivity for the Tl1-x In1-x Ge x Se2 and Tl1-x In1-x Si x Se2 single crystals were explored and compared with previously reported Tl1-x In1-x Sn x Se2. Based on our investigations, a model of centre re-charging is proposed. Contrary to other investigated crystals in Tl1-x In1-x Ge x Se2 single crystals for x = 0.1 we observe extraordinarily enormous photoresponse, which exceed more than nine times the dark current. X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated surfaces of Tl1-x In1-x GexSe2 (x = 0.1 and 0.2) single crystals have been studied. These results indicate that the relatively low hygroscopicity of the studied single crystals is typical for the Tl1-x In1-x Ge x Se2 crystals, a property that is very important for handling these quaternary selenides as infrared materials operating at ambient conditions.

Investigation of the adsorption of amino acids on Pd(1 1 1): A density functional theory study

International Nuclear Information System (INIS)

James, Joanna N.; Han, Jeong Woo; Sholl, David S.

2014-01-01

Graphical abstract: - Highlights: • Density functional theory calculations have been performed to study the adsorption of glycine, alanine, norvaline, valine, proline, cysteine, and serine on Pd(1 1 1). • The common structural framework for the adsorption of most amino acids onto Pd(1 1 1) is in a tridentate fashion via a nitrogen atom and two oxygen atoms. • The shifts in vibrational frequencies associated with NHH and COO support the adsorption patterns of amino acids we examined. • The adsorption strength of amino acids depends on how much the molecules deform during the adsorption process. - Abstract: Density functional theory calculations have been used to study the adsorption of glycine, alanine, norvaline, valine, proline, cysteine, and serine on Pd(1 1 1). Most amino acids except cysteine adsorb onto the surface in a tridentate fashion through a nitrogen atom and both oxygen atoms. For cysteine, an additional bond is formed with the surface due to the strong affinity of the sulfur atom, resulting in a significantly larger adsorption energy. The adsorption patterns of amino acids we examined are supported by the shifts in vibrational frequencies associated with NHH and COO. The adsorption strength of amino acids depends on how much the molecules deform during the adsorption process. Understanding the adsorption of amino acids on Pd(1 1 1) provides fundamental information for future consideration of the interactions between their derivatives or more complicated biomolecules and metal surfaces

Dicty_cDB: Contig-U03323-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U03323-1 no gap 533 2 4820223 4820756 PLUS 2 1 U03323 0 0 0 0 0 0 0 0 0 0 0 0 1 1 Show Contig...-U03323-1 Contig ID Contig-U03323-1 Contig update 2001. 8.29 Contig sequence >Contig-U03323-1 (Contig...-U03323-1Q) /CSM_Contig/Contig-U03323-1Q.Seq.d ACATGTGACATTACTATTGGTAAATGTCAATGTTTAAAAAATACATGGTC ...TCAATAATGGTGGTGGTGGTGGTTTAGGT GAAACCCCCAATAGTAATAGTAATAGTGGTGAACTAGTTATCCCACCAAA ATCAAATACTACATTAAATGAAGAAACAGGTGG Gap no gap Contig... Link to clone list U03323 List of clone(s) est1= FC-IC0176F ,1,534 Translated Amino Acid sequence TCDITIGKC

Dicty_cDB: Contig-U09822-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U09822-1 gap included 1255 3 5930658 5929418 MINUS 5 6 U09822 3 0 2 0 0 0 0 0 0 0 0 0 0 0 Show Contig...-U09822-1 Contig ID Contig-U09822-1 Contig update 2002. 9.13 Contig sequence >Contig-U09822-1 (Contig-U09822-1Q) /CSM_Contig/Contig-U0982...AAAAGAAAAAAAAAAAAAAAAGATTTAATTAAATAAAAAAAAA AAAAAAAAAAAAAAA Gap gap included Contig length 1255 Chromosome n...,975 est6= VSA519Z ,780,1257 Translated Amino Acid sequence QPFYLVQSMFEPIQDSSFTSIGEIISYDTIG...rfn*ikkkkkk k Frame C: QPFYLVQSMFEPIQDSSFTSIGEIISYDTIGFDGKINTAVMSSLSPSTMYFYCVGDKS

Single-stranded nucleic acids promote SAMHD1 complex formation.

Science.gov (United States)

Tüngler, Victoria; Staroske, Wolfgang; Kind, Barbara; Dobrick, Manuela; Kretschmer, Stefanie; Schmidt, Franziska; Krug, Claudia; Lorenz, Mike; Chara, Osvaldo; Schwille, Petra; Lee-Kirsch, Min Ae

2013-06-01

SAM domain and HD domain-containing protein 1 (SAMHD1) is a dGTP-dependent triphosphohydrolase that degrades deoxyribonucleoside triphosphates (dNTPs) thereby limiting the intracellular dNTP pool. Mutations in SAMHD1 cause Aicardi-Goutières syndrome (AGS), an inflammatory encephalopathy that mimics congenital viral infection and that phenotypically overlaps with the autoimmune disease systemic lupus erythematosus. Both disorders are characterized by activation of the antiviral cytokine interferon-α initiated by immune recognition of self nucleic acids. Here we provide first direct evidence that SAMHD1 associates with endogenous nucleic acids in situ. Using fluorescence cross-correlation spectroscopy, we demonstrate that SAMHD1 specifically interacts with ssRNA and ssDNA and establish that nucleic acid-binding and formation of SAMHD1 complexes are mutually dependent. Interaction with nucleic acids and complex formation do not require the SAM domain, but are dependent on the HD domain and the C-terminal region of SAMHD1. We finally demonstrate that mutations associated with AGS exhibit both impaired nucleic acid-binding and complex formation implicating that interaction with nucleic acids is an integral aspect of SAMHD1 function.

The Gamma Gap and All-Cause Mortality.

Directory of Open Access Journals (Sweden)

Stephen P Juraschek

Full Text Available The difference between total serum protein and albumin, i.e. the gamma gap, is a frequently used clinical screening measure for both latent infection and malignancy. However, there are no studies defining a positive gamma gap. Further, whether it is an independent risk factor of mortality is unknown.This study examined the association between gamma gap, all-cause mortality, and specific causes of death (cardiovascular, cancer, pulmonary, or other in 12,260 participants of the National Health and Nutrition Examination Survey (NHANES from 1999-2004. Participants had a comprehensive metabolic panel measured, which was linked with vital status data from the National Death Index. Cause of death was based on ICD10 codes from death certificates. Analyses were performed with Cox proportional hazards models adjusted for mortality risk factors. The mean (SE age was 46 (0.3 years and the mean gamma gap was 3.0 (0.01 g/dl. The population was 52% women and 10% black. During a median follow-up period of 4.8 years (IQR: 3.3 to 6.2 years, there were 723 deaths. The unadjusted 5-year cumulative incidences across quartiles of the gamma gap (1.7-2.7, 2.8-3.0, 3.1-3.2, and 3.3-7.9 g/dl were 5.7%, 4.2%, 5.5%, and 7.8%. After adjustment for risk factors, participants with a gamma gap of ≥3.1 g/dl had a 30% higher risk of death compared to participants with a gamma gap <3.1 g/dl (HR: 1.30; 95%CI: 1.08, 1.55; P = 0.006. Gamma gap (per 1.0 g/dl was most strongly associated with death from pulmonary causes (HR 2.22; 95%CI: 1.19, 4.17; P = 0.01.The gamma gap is an independent risk factor for all-cause mortality at values as low as 3.1 g/dl (in contrast to the traditional definition of 4.0 g/dl, and is strongly associated with death from pulmonary causes. Future studies should examine the biologic pathways underlying these associations.

Amino acid transporter genes are essential for FLO11-dependent and FLO11-independent biofilm formation and invasive growth in Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Rasmus Torbensen

Full Text Available Amino acids can induce yeast cell adhesion but how amino acids are sensed and signal the modulation of the FLO adhesion genes is not clear. We discovered that the budding yeast Saccharomyces cerevisiae CEN.PK evolved invasive growth ability under prolonged nitrogen limitation. Such invasive mutants were used to identify amino acid transporters as regulators of FLO11 and invasive growth. One invasive mutant had elevated levels of FLO11 mRNA and a Q320STOP mutation in the SFL1 gene that encodes a protein kinase A pathway regulated repressor of FLO11. Glutamine-transporter genes DIP5 and GNP1 were essential for FLO11 expression, invasive growth and biofilm formation in this mutant. Invasive growth relied on known regulators of FLO11 and the Ssy1-Ptr3-Ssy5 complex that controls DIP5 and GNP1, suggesting that Dip5 and Gnp1 operates downstream of the Ssy1-Ptr3-Ssy5 complex for regulation of FLO11 expression in a protein kinase A dependent manner. The role of Dip5 and Gnp1 appears to be conserved in the S. cerevisiae strain ∑1278b since the dip5 gnp1 ∑1278b mutant showed no invasive phenotype. Secondly, the amino acid transporter gene GAP1 was found to influence invasive growth through FLO11 as well as other FLO genes. Cells carrying a dominant loss-of-function PTR3(647::CWNKNPLSSIN allele had increased transcription of the adhesion genes FLO1, 5, 9, 10, 11 and the amino acid transporter gene GAP1. Deletion of GAP1 caused loss of FLO11 expression and invasive growth. However, deletions of FLO11 and genes encoding components of the mitogen-activated protein kinase pathway or the protein kinase A pathway were not sufficient to abolish invasive growth, suggesting involvement of other FLO genes and alternative pathways. Increased intracellular amino acid pools in the PTR3(647::CWNKNPLSSIN-containing strain opens the possibility that Gap1 regulates the FLO genes through alteration of the amino acid pool sizes.

Gas-phase studies of copper catalyzed aerobic cross coupling of thiol esters and arylboronic acids

Czech Academy of Sciences Publication Activity Database

Tsybizová, A.; Schröder, Detlef; Roithová, J.; Henke, A.; Šrogl, Jiří

2014-01-01

Roč. 27, č. 3 (2014), s. 198-203 ISSN 0894-3230 R&D Projects: GA ČR GAP207/12/0846 Grant - others:GA ČR(CZ) GAP207/11/0338 Institutional support: RVO:61388963 Keywords : boronic acids * catalysis * copper * cross coupling * electrospray ionization * mass spectrometry * kinetic studies Subject RIV: CC - Organic Chemistry Impact factor: 1.380, year: 2014

Composition-tuned band gap energy and refractive index in GaS{sub x}Se{sub 1−x} layered mixed crystals

Energy Technology Data Exchange (ETDEWEB)

Isik, Mehmet, E-mail: mehmet.isik@atilim.edu.tr [Department of Electrical and Electronics Engineering, Atilim University, 06836, Ankara (Turkey); Gasanly, Nizami [Department of Physics, Middle East Technical University, 06800, Ankara (Turkey); Virtual International Scientific Research Centre, Baku State University, 1148, Baku (Azerbaijan)

2017-04-01

Transmission and reflection measurements on GaS{sub x}Se{sub 1−x} mixed crystals (0 ≤ x ≤ 1) were carried out in the 400–1000 nm spectral range. Band gap energies of the studied crystals were obtained using the derivative spectra of transmittance and reflectance. The compositional dependence of band gap energy revealed that as sulfur (selenium) composition is increased (decreased) in the mixed crystals, band gap energy increases quadratically from 1.99 eV (GaSe) to 2.55 eV (GaS). Spectral dependencies of refractive indices of the mixed crystals were plotted using the reflectance spectra. It was observed that refractive index decreases nearly in a linear behavior with increasing band gap energy for GaS{sub x}Se{sub 1−x} mixed crystals. Moreover, the composition ratio of the mixed crystals was obtained from the energy dispersive spectroscopy measurements. The atomic compositions of the studied crystals are well-matched with composition x increasing from 0 to 1 by intervals of 0.25. - Highlights: • Transmission and reflection experiments were performed on GaS{sub x}Se{sub 1−x} mixed crystals. • Derivative spectra of transmittance and reflectance were used for analyses. • Compositional dependence of band gap energy and refractive index were reported.

Bile Acids Trigger GLP-1 Release Predominantly by Accessing Basolaterally Located G Protein-Coupled Bile Acid Receptors

DEFF Research Database (Denmark)

Brighton, Cheryl A.; Rievaj, Juraj; Kuhre, Rune E.

2015-01-01

Bile acids are well-recognized stimuli of glucagon-like peptide-1 (GLP-1) secretion. This action has been attributed to activation of the G protein-coupled bile acid receptor GPBAR1 (TGR5), although other potential bile acid sensors include the nuclear farnesoid receptor and the apical sodium......-coupled bile acid transporter ASBT. The aim of this study was to identify pathways important for GLP-1 release and to determine whether bile acids target their receptors on GLP-1-secreting L-cells from the apical or basolateral compartment. Using transgenic mice expressing fluorescent sensors specifically in L...... to either TLCA or TDCA. We conclude that the action of bile acids on GLP-1 secretion is predominantly mediated by GPBAR1 located on the basolateral L-cell membrane, suggesting that stimulation of gut hormone secretion may include postabsorptive mechanisms....

Clinical outcome of increased flexion gap after total knee arthroplasty. Can controlled gap imbalance improve knee flexion?

Science.gov (United States)

Ismailidis, P; Kuster, M S; Jost, B; Giesinger, K; Behrend, H

2017-06-01

Increased range of motion (ROM) while maintaining joint stability is the goal of modern total knee arthroplasty (TKA). A biomechanical study has shown that small increases in flexion gap result in decreased tibiofemoral force beyond 90° flexion. The purpose of this paper was to investigate clinical implications of controlled increased flexion gap. Four hundred and four TKAs were allocated into one of two groups and analysed retrospectively. In the first group (n = 352), flexion gap exceeded extension gap by 2.5 mm, while in the second group (n = 52) flexion gap was equal to the extension gap. The procedures were performed from 2008 to 2012. The patients were reviewed 12 months postoperatively. Objective clinical results were assessed for ROM, mediolateral and sagittal stability. Patient-reported outcome measures were the WOMAC score and the Forgotten Joint Score (FJS-12). After categorizing postoperative flexion into three groups (poor < 90°, satisfactory 91°-119°, good ≥ 120°) significantly more patients in group 1 achieved satisfactory or good ROM (p = 0.006). Group 1 also showed a significantly higher mean FJS-12 (group 1: 73, group 2: 61, p = 0.02). The mean WOMAC score was 11 in the first and 14 in the second group (n.s.). Increase in flexion gap did not influence knee stability. The clinical relevance of this study is that a controlled flexion gap increase of 2.5 mm may have a positive effect on postoperative flexion and patient satisfaction after TKA. Neither knee stability in the coronal and sagittal planes nor complications were influenced by a controlled increase in flexion gap. III.

Pharmacokinetic analysis of trichloroethylene metabolism in male B6C3F1 mice: Formation and disposition of trichloroacetic acid, dichloroacetic acid, S-(1,2-dichlorovinyl)glutathione and S-(1,2-dichlorovinyl)-L-cysteine

Science.gov (United States)

Kim, Sungkyoon; Kim, David; Pollack, Gary M.; Collins, Leonard B.; Rusyn, Ivan

2009-01-01

Trichloroethylene (TCE) is a well-known carcinogen in rodents and concerns exist regarding its potential carcinogenicity in humans. Oxidative metabolites of TCE, such as dichloroacetic acid (DCA) and trichloroacetic acid (TCA), are thought to be hepatotoxic and carcinogenic in mice. The reactive products of glutathione conjugation, such as S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and S-(1,2-dichlorovinyl) glutathione (DCVG), are associated with renal toxicity in rats. Recently, we developed a new analytical method for simultaneous assessment of these TCE metabolites in small-volume biological samples. Since important gaps remain in our understanding of the pharmacokinetics of TCE and its metabolites, we studied a time-course of DCA, TCA, DCVG and DCVG formation and elimination after a single oral dose of 2100 mg/kg TCE in male B6C3F1 mice. Based on systemic concentration-time data, we constructed multi-compartment models to explore the kinetic properties of the formation and disposition of TCE metabolites, as well as the source of DCA formation. We conclude that TCE-oxide is the most likely source of DCA. According to the best-fit model, bioavailability of oral TCE was ~74%, and the half-life and clearance of each metabolite in the mouse were as follows: DCA: 0.6 hr, 0.081 ml/hr; TCA: 12 hr, 3.80 ml/hr; DCVG: 1.4 hr, 16.8 ml/hr; DCVC: 1.2 hr, 176 ml/hr. In B6C3F1 mice, oxidative metabolites are formed in much greater quantities (~3600 fold difference) than glutathione-conjugative metabolites. In addition, DCA is produced to a very limited extent relative to TCA, while most of DCVG is converted into DCVC. These pharmacokinetic studies provide insight into the kinetic properties of four key biomarkers of TCE toxicity in the mouse, representing novel information that can be used in risk assessment. PMID:19409406

Pharmacokinetic analysis of trichloroethylene metabolism in male B6C3F1 mice: Formation and disposition of trichloroacetic acid, dichloroacetic acid, S-(1,2-dichlorovinyl)glutathione and S-(1,2-dichlorovinyl)-L-cysteine

International Nuclear Information System (INIS)

Kim, Sungkyoon; Kim, David; Pollack, Gary M.; Collins, Leonard B.; Rusyn, Ivan

2009-01-01

Trichloroethylene (TCE) is a well-known carcinogen in rodents and concerns exist regarding its potential carcinogenicity in humans. Oxidative metabolites of TCE, such as dichloroacetic acid (DCA) and trichloroacetic acid (TCA), are thought to be hepatotoxic and carcinogenic in mice. The reactive products of glutathione conjugation, such as S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and S-(1,2-dichlorovinyl) glutathione (DCVG), are associated with renal toxicity in rats. Recently, we developed a new analytical method for simultaneous assessment of these TCE metabolites in small-volume biological samples. Since important gaps remain in our understanding of the pharmacokinetics of TCE and its metabolites, we studied a time-course of DCA, TCA, DCVG and DCVG formation and elimination after a single oral dose of 2100 mg/kg TCE in male B6C3F1 mice. Based on systemic concentration-time data, we constructed multi-compartment models to explore the kinetic properties of the formation and disposition of TCE metabolites, as well as the source of DCA formation. We conclude that TCE-oxide is the most likely source of DCA. According to the best-fit model, bioavailability of oral TCE was ∼ 74%, and the half-life and clearance of each metabolite in the mouse were as follows: DCA: 0.6 h, 0.081 ml/h; TCA: 12 h, 3.80 ml/h; DCVG: 1.4 h, 16.8 ml/h; DCVC: 1.2 h, 176 ml/h. In B6C3F1 mice, oxidative metabolites are formed in much greater quantities (∼ 3600 fold difference) than glutathione-conjugative metabolites. In addition, DCA is produced to a very limited extent relative to TCA, while most of DCVG is converted into DCVC. These pharmacokinetic studies provide insight into the kinetic properties of four key biomarkers of TCE toxicity in the mouse, representing novel information that can be used in risk assessment.

The Gamma Gap and All-Cause Mortality

Science.gov (United States)

Juraschek, Stephen P.; Moliterno, Alison R.; Checkley, William; Miller, Edgar R.

2015-01-01

Background The difference between total serum protein and albumin, i.e. the gamma gap, is a frequently used clinical screening measure for both latent infection and malignancy. However, there are no studies defining a positive gamma gap. Further, whether it is an independent risk factor of mortality is unknown. Methods and Findings This study examined the association between gamma gap, all-cause mortality, and specific causes of death (cardiovascular, cancer, pulmonary, or other) in 12,260 participants of the National Health and Nutrition Examination Survey (NHANES) from 1999–2004. Participants had a comprehensive metabolic panel measured, which was linked with vital status data from the National Death Index. Cause of death was based on ICD10 codes from death certificates. Analyses were performed with Cox proportional hazards models adjusted for mortality risk factors. The mean (SE) age was 46 (0.3) years and the mean gamma gap was 3.0 (0.01) g/dl. The population was 52% women and 10% black. During a median follow-up period of 4.8 years (IQR: 3.3 to 6.2 years), there were 723 deaths. The unadjusted 5-year cumulative incidences across quartiles of the gamma gap (1.7–2.7, 2.8–3.0, 3.1–3.2, and 3.3–7.9 g/dl) were 5.7%, 4.2%, 5.5%, and 7.8%. After adjustment for risk factors, participants with a gamma gap of ≥3.1 g/dl had a 30% higher risk of death compared to participants with a gamma gap gap (per 1.0 g/dl) was most strongly associated with death from pulmonary causes (HR 2.22; 95%CI: 1.19, 4.17; P = 0.01). Conclusions The gamma gap is an independent risk factor for all-cause mortality at values as low as 3.1 g/dl (in contrast to the traditional definition of 4.0 g/dl), and is strongly associated with death from pulmonary causes. Future studies should examine the biologic pathways underlying these associations. PMID:26629820

Using Information Gap Activity to Increase Students' speaking Skill at the Twelve Grade of MAN 1 Pamekasan

Directory of Open Access Journals (Sweden)

Ansharul Fuqaha

2015-05-01

Full Text Available Based on the researchers’ observation on the preliminary study on the teachingof speaking, the problem was found that the students’ speaking skill in the teaching and learning was very low. It was because the class was heterogeneousand the teacher used monotonous teaching activity. To cope of this problem, theresearcher employed the Information gap activity. This study tries to prove how the Information-gap activity can increase students’ speaking skill at the thirdgrade of MAN 1 Pamekasan. The study was design to increase the students’speaking skill by using Information gap activity at MAN 1 Pamekasan. Thestudy was collaborative classroom action research in which the researcher andthe collaborator worked together, the researcher acted as the teacher while thecollaborator observed the students during the implementation of the strategy. This study was conducted in one cycle consisting of six meetings using thefollowing procedures; planning, implementing, observing and reflecting. The data of the study were collected through the observation checklists, field notes,and questionnaires. The subject of the study were 41 students of third grade on science 3 program MAN 1 Pamekasan. 

Sphingosine-1-Phosphate reduces ischemia/reperfusion injury by phosphorylating the gap junction protein Connexin43

DEFF Research Database (Denmark)

Morel, Sandrine; Christoffersen, Christina; Axelsen, Lene N

2016-01-01

recruitment seems only indirectly affected. Importantly, short-term S1P treatment at the onset of reperfusion was sufficient to reduce ischemia/reperfusion injury in isolated perfused hearts. Mechanistic in vitro and ex vivo studies revealed that 5 min of S1P treatment induced phosphorylation of the gap...

Preparation of 131I-asialo-α1-acid glycoprotein

International Nuclear Information System (INIS)

Rijk, P.P. van

1975-01-01

α 1 -Acid glycoprotein (orosomucoid) was prepared from a byproduct of the ethanol plasma fractionation by means of ion-exchange procedures. Immunoelectrophoresis suggested a high degree of purity; the purified protein contained 13.5% sialic acid and 17.8% hexose. The α 1 -acid glycoprotein was modified by removal of sialic acid with neurominidase (E.C. 3.2.1.18) followed by iodination with 131 I. The purpose of the preparation, its potential use as a pharmacon for liver-function studies in nuclear medicine, is the subject of further study

Photochemical stability and photovoltaic performance of low-band gap polymers based on dithiophene with different bridging atoms

DEFF Research Database (Denmark)

Helgesen, Martin; Sørensen, Thomas J.; Manceau, Matthieu

2011-01-01

New low-band gap polymers based on dithienylbenzothiadiazole (DBT) and dithiophene with different bridging atoms have been synthesized and explored in a comparative study on the photochemical stability and photovoltaic performance. Two differently modified DBT units were exploited, namely 5,6- bis......(tetradecyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (DBT1) and 4,7-bis(4-dodecylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (DBT2). In thin films the polymers had optical band gaps in the range of 1.51-1.70 eV where the DBT2 based polymers are red shifted 61-81 nm compared to the DBT1 based polymers...... indicating greater interchain packing when the side chains are situated on the thienyl groups compared to on the benzothiadiazole unit. The best photovoltaic devices based on blends of polymer and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) were prepared with polymers based on the DBT1 unit giving...

Strategies for Closing the ITRS Funding Gap

Science.gov (United States)

2008-08-01

The semiconductor industry needs to find creative ways to close the $1.1 – 1.5B research gap , first noted in 2003, between the funding being...2008 2. REPORT TYPE 3. DATES COVERED 00-00-2008 to 00-00-2008 4. TITLE AND SUBTITLE Strategies for Closing the ITRS Funding Gap 5a. CONTRACT...Rev. 8-98) Prescribed by ANSI Std Z39-18 STRATEGIES FOR CLOSING THE ITRS FUNDING GAP # Yaw S. Obeng, Stephen Knight, and Joaquin V. Martinez de

Interaction of humic acids and humic-acid-like polymers with herpes simplex virus type 1

Science.gov (United States)

Klöcking, Renate; Helbig, Björn

The study was performed in order to compare the antiviral activity against herpes simplex virus type 1 (HSV-1) of synthetic humic-acid-like polymers to that of their low-molecular-weight basic compounds and naturally occurring humic acids (HA) in vitro. HA from peat water showed a moderate antiviral activity at a minimum effective concentration (MEC) of 20 µg/ml. HA-like polymers, i.e. the oxidation products of caffeic acid (KOP), hydrocaffeic acid (HYKOP), chlorogenic acid (CHOP), 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), nordihydroguaretic acid (NOROP), gentisinic acid (GENOP), pyrogallol (PYROP) and gallic acid (GALOP), generally inhibit virus multiplication, although with different potency and selectivity. Of the substances tested, GENOP, KOP, 3,4-DHPOP and HYKOP with MEC values in the range of 2 to 10 µg/ml, proved to be the most potent HSV-1 inhibitors. Despite its lower antiviral potency (MEC 40 µg/ml), CHOP has a remarkable selectivity due to the high concentration of this polymer that is tolerated by the host cells (>640 µg/ml). As a rule, the antiviral activity of the synthetic compounds was restricted to the polymers and was not preformed in the low-molecular-weight basic compounds. This finding speaks in favour of the formation of antivirally active structures during the oxidative polymerization of phenolic compounds and, indirectly, of corresponding structural parts in different HA-type substances.

Functional Gap Analysis of the Maritime Operations Centers

Science.gov (United States)

2009-12-01

Messaging Services TBMCS , DJC2 MI.1.3.5 Manage Suspense Control Capability Gap MI.1.3.6 Provide Component IM Cell Services Capability Gap MI.1.4 Provide...Admin Support MSRT MI.1.3.3 Manage Electronic File Plan Capability Gap MI.1.3.4 Manage Messaging Services TBMCS , DJC2 MI.1.3.5 Manage Suspense...1.5.9 Execute C4 Policies & Procedures for the Joint Operations Area GCCS-J, DCGS-N, TBMCS , CENTRIX-M EHQ.1.11 Sub Component Interagency

Effect of chenodeoxycholic acid and the bile acid sequestrant colesevelam on glucagon-like peptide-1 secretion

DEFF Research Database (Denmark)

Hansen, Morten; Scheltema, Matthijs J; Sonne, David P

2016-01-01

AIMS: In patients with type 2 diabetes, rectal administration of bile acids increases glucagon-like peptide-1 (GLP-1) secretion and reduces plasma glucose. In addition, oral bile acid sequestrants (BASs) reduce blood glucose by an unknown mechanism. In this study we evaluated the effects...... of the primary human bile acid, chenodeoxycholic acid (CDCA), and the BAS, colesevelam, instilled into the stomach, on plasma levels of GLP-1, glucose-dependent insulinotropic polypeptide, glucose, insulin, C-peptide, glucagon, cholecystokinin and gastrin as well as gastric emptying, gallbladder volume, appetite......, and delayed gastric emptying. We speculate that bile acid-induced activation of TGR5 on L cells increases GLP-1 secretion, which in turn may result in amplification of glucose-stimulated insulin secretion. Furthermore our data suggest that colesevelam does not have an acute effect on GLP-1 secretion in humans....

Podospermic acid, 1,3,5-tri-O-(7,8-dihydrocaffeoyl) quinic acid from Podospermum laciniatum (Asteraceae)

DEFF Research Database (Denmark)

Zidorn, Christian; Petersen, Bent O.; Udovicic ́, Vedrana

2005-01-01

A phytochemical investigation of Podospermum laciniatum (L.) DC. (Asteraceae) yielded the new quinic acid derivative podospermic acid (1,3,5-tridihydrocaffeoylquinic acid), which was named after the genus it was isolated from. The structure was established by HR mass spectrometry and extensive 1D...

Net alkalinity and net acidity 1: Theoretical considerations

International Nuclear Information System (INIS)

Kirby, Carl S.; Cravotta, Charles A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO 2 , and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined 'CO 2 -acidity' is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO 2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass-action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mgL -1 as CaCO 3 (based on pH and analytical concentrations of dissolved Fe II , Fe III , Mn, and Al in mgL -1 ):acidity calculated =50{1000(10 -pH )+[2(Fe II )+3(Fe III )]/56+2(Mn) /55+3(Al)/27}underestimates contributions from HSO 4 - and H + , but overestimates the acidity due to Fe 3+ and Al 3+ . However, these errors tend to approximately cancel each other. It is demonstrated that 'net alkalinity' is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the

Acid-base strengths in 1,2-dichloroethane

NARCIS (Netherlands)

Bos, M.; Dahmen, E.A.M.F.

1973-01-01

The pKa value of hydriodic acid in 1,2-dichloroethane was determined from conductivity measurements. A glass electrode was calibrated for dichloroethane in the potentiometric titration of hydriodic acid with tetramethylguanidine. From potentiometric titrations, the pKa values in dichloroethane of

Protein kinase C-dependent regulation of connexin43 gap junctions and hemichannels

DEFF Research Database (Denmark)

Alstrøm, Jette Skov; Stroemlund, Line Waring; Nielsen, Morten Schak

2015-01-01

Connexin43 (Cx43) generates intercellular gap junction channels involved in, among others, cardiac and brain function. Gap junctions are formed by the docking of two hemichannels from neighbouring cells. Undocked Cx43 hemichannels can upon different stimuli open towards the extracellular matrix...... and allow transport of molecules such as fluorescent dyes and ATP. A range of phosphorylated amino acids have been detected in the C-terminus of Cx43 and their physiological role has been intensively studied both in the gap junctional form of Cx43 and in its hemichannel configuration. We present the current...... knowledge of protein kinase C (PKC)-dependent regulation of Cx43 and discuss the divergent results....

Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants 1

Science.gov (United States)

Yang, Joan C.; Loewus, Frank A.

1975-01-01

l-Ascorbic acid-1-14C and its oxidation product, dehydro-l-ascorbic acid, produced labeled oxalic acid in oxalate-accumulating plants such as spinach seedlings (Spinacia oleracea) and the detached leaves of woodsorrel (Oxalis stricta and O. oregana), shamrock (Oxalis adenopylla), and begonia (Begonia evansiana). In O. oregana, conversion occurred equally well in the presence or absence of light. This relationship between l-ascorbic acid metabolism and oxalic acid formation must be given careful consideration in attempts to explain oxalic accumulation in plants. PMID:16659288

Lewis Acid-Base Chemistry of 7-Azaisoindigo-Based Organic Semiconductors.

Science.gov (United States)

Randell, Nicholas M; Fransishyn, Kyle M; Kelly, Timothy L

2017-07-26

Low-band-gap organic semiconductors are important in a variety of organic electronics applications, such as organic photovoltaic devices, photodetectors, and field effect transistors. Building on our previous work, which introduced 7-azaisoindigo as an electron-deficient building block for the synthesis of donor-acceptor organic semiconductors, we demonstrate how Lewis acids can be used to further tune the energies of the frontier molecular orbitals. Coordination of a Lewis acid to the pyridinic nitrogen of 7-azaisoindigo greatly diminishes the electron density in the azaisoindigo π-system, resulting in a substantial reduction in the lowest unoccupied molecular orbital (LUMO) energy. This results in a smaller highest occupied molecular orbital-LUMO gap and shifts the lowest-energy electronic transition well into the near-infrared region. Both H + and BF 3 are shown to coordinate to azaisoindigo and affect the energy of the S 0 → S 1 transition. A combination of time-dependent density functional theory and UV/vis and 1 H NMR spectroscopic titrations reveal that when two azaisoindigo groups are present and high concentrations of acid are used, both pyridinic nitrogens bind Lewis acids. Importantly, we demonstrate that this acid-base chemistry can be carried out at the solid-vapor interface by exposing thin films of aza-substituted organic semiconductors to vapor-phase BF 3 ·Et 2 O. This suggests the possibility of using the BF 3 -bound 7-azaisoindigo-based semiconductors as n-type materials in various organic electronic applications.

Agdc1p - a Gallic Acid Decarboxylase Involved in the Degradation of Tannic Acid in the Yeast Blastobotrys (Arxula) adeninivorans.

Science.gov (United States)

Meier, Anna K; Worch, Sebastian; Böer, Erik; Hartmann, Anja; Mascher, Martin; Marzec, Marek; Scholz, Uwe; Riechen, Jan; Baronian, Kim; Schauer, Frieder; Bode, Rüdiger; Kunze, Gotthard

2017-01-01

Tannins and hydroxylated aromatic acids, such as gallic acid (3,4,5-trihydroxybenzoic acid), are plant secondary metabolites which protect plants against herbivores and plant-associated microorganisms. Some microbes, such as the yeast Arxula adeninivorans are resistant to these antimicrobial substances and are able to use tannins and gallic acid as carbon sources. In this study, the Arxula gallic acid decarboxylase (Agdc1p) which degrades gallic acid to pyrogallol was characterized and its function in tannin catabolism analyzed. The enzyme has a higher affinity for gallic acid (K m -0.7 ± 0.2 mM, k cat -42.0 ± 8.2 s -1 ) than to protocatechuic acid (3,4-dihydroxybenzoic acid) (K m -3.2 ± 0.2 mM, k cat -44.0 ± 3.2 s -1 ). Other hydroxylated aromatic acids, such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid are not gallic acid decarboxylase substrates. A. adeninivorans G1212/YRC102-AYNI1-AGDC1, which expresses the AGDC1 gene under the control of the strong nitrate inducible AYNI1 promoter achieved a maximum gallic acid decarboxylase activity of 1064.4 U/l and 97.5 U/g of dry cell weight in yeast grown in minimal medium with nitrate as nitrogen source and glucose as carbon source. In the same medium, gallic acid decarboxylase activity was not detected for the control strain G1212/YRC102 with AGDC1 expression under the control of the endogenous promoter. Gene expression analysis showed that AGDC1 is induced by gallic acid and protocatechuic acid. In contrast to G1212/YRC102-AYNI1-AGDC1 and G1212/YRC102, A. adeninivorans G1234 [Δ agdc1 ] is not able to grow on medium with gallic acid as carbon source but can grow in presence of protocatechuic acid. This confirms that Agdc1p plays an essential role in the tannic acid catabolism and could be useful in the production of catechol and cis,cis -muconic acid. However, the protocatechuic acid catabolism via Agdc1p to catechol seems to be

Exploring the Potential of Fungal Arylacetonitrilases in Mandelic Acid Synthesis

Czech Academy of Sciences Publication Activity Database

Veselá, Alicja Barbara; Křenková, Alena; Martínková, Ludmila

2015-01-01

Roč. 57, č. 5 (2015), s. 466-474 ISSN 1073-6085 R&D Projects: GA ČR(CZ) GAP504/11/0394 Institutional support: RVO:61388971 Keywords : Fungal arylacetonitrilases * (R)-Mandelic acid manufacture * (R,S)-Mandelonitrile hydrolysis Subject RIV: CE - Biochemistry Impact factor: 1.752, year: 2015

Spatial distribution and size of small canopy gaps created by Japanese black bears: estimating gap size using dropped branch measurements.

Science.gov (United States)

Takahashi, Kazuaki; Takahashi, Kaori

2013-06-10

Japanese black bears, a large-bodied omnivore, frequently create small gaps in the tree crown during fruit foraging. However, there are no previous reports of black bear-created canopy gaps. To characterize physical canopy disturbance by black bears, we examined a number of parameters, including the species of trees in which canopy gaps were created, gap size, the horizontal and vertical distribution of gaps, and the size of branches broken to create gaps. The size of black bear-created canopy gaps was estimated using data from branches that had been broken and dropped on the ground. The disturbance regime was characterized by a highly biased distribution of small canopy gaps on ridges, a large total overall gap area, a wide range in gap height relative to canopy height, and diversity in gap size. Surprisingly, the annual rate of bear-created canopy gap formation reached 141.3 m2 ha-1 yr-1 on ridges, which were hot spots in terms of black bear activity. This rate was approximately 6.6 times that of tree-fall gap formation on ridges at this study site. Furthermore, this rate was approximately two to three times that of common tree-fall gap formation in Japanese forests, as reported in other studies. Our findings suggest that the ecological interaction between black bears and fruit-bearing trees may create a unique light regime, distinct from that created by tree falls, which increases the availability of light resources to plants below the canopy.

Operation of low-noise single-gap RPC modules exposed to ionisation rates up to 1 kHz/cm$^2$

CERN Document Server

Cwiok, M; Dominik, Wojciech; Górski, M; Królikowski, J; 10.1016/j.nima.2004.06.123

2004-01-01

Two single gap medium-size RPC modules, made of bakelite plates of very good mechanical quality of the surface and having initial volume resistivity of 1 multiplied by 10**1**0 omegacm, were tested in the Gamma Irradiation Facility at CERN at ionisation rates up to 1 kHz/cm **3. The internal surfaces facing the gas volume of one RPC module were cladded with a thin layer of linseed oil varnish for comparison of oiled and non-oiled RPC operation. The results refer to the gas mixture of C//2H//2F //4/isobutane (97:3) with SF//6 addition below 1%. The single gap modules exhibited full detection efficiency plateau for the high voltage range of about 1 kV at full intensity of gamma rays. Good timing characteristics allowed to reach 95% efficiency at fully opened irradiation source with time window of 20 ns. The intrinsic noise rate for a non-oiled and an oiled RPC gap was, respectively, below 5 and 1 Hz/cm**2 at full efficiency over 1 k V voltage range.

Dicty_cDB: Contig-U15069-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U15069-1 no gap 1241 1 2719927 2720886 PLUS 37 43 U15069 16 2 0 0 0 5 8 0 0 1 1 0 4 0 Show Contig...-U15069-1 Contig ID Contig-U15069-1 Contig update 2004. 6.11 Contig sequence >Contig-U15069-1 (Contig...-U15069-1Q) /CSM_Contig/Contig-U15069-1Q.Seq.d TTTCAAACCAAAACATAAAATAATTAAAAATGACAACTGTTAAACCA...AAAAATAAAATAAATAAAAATAGTTTTAAA Gap no gap Contig length 1241 Chromosome number (1..6, M) 1 Chromosome length...07Z ,263,623 est42= VSJ431Z ,390,646 est43= CHB363Z ,460,1187 Translated Amino Acid sequence snqnik*lkmttvkptspenprvffditig

From the Kohn-Sham band gap to the fundamental gap in solids. An integer electron approach.

Science.gov (United States)

Baerends, E J

2017-06-21

It is often stated that the Kohn-Sham occupied-unoccupied gap in both molecules and solids is "wrong". We argue that this is not a correct statement. The KS theory does not allow to interpret the exact KS HOMO-LUMO gap as the fundamental gap (difference (I - A) of electron affinity (A) and ionization energy (I), twice the chemical hardness), from which it indeed differs, strongly in molecules and moderately in solids. The exact Kohn-Sham HOMO-LUMO gap in molecules is much below the fundamental gap and very close to the much smaller optical gap (first excitation energy), and LDA/GGA yield very similar gaps. In solids the situation is different: the excitation energy to delocalized excited states and the fundamental gap (I - A) are very similar, not so disparate as in molecules. Again the Kohn-Sham and LDA/GGA band gaps do not represent (I - A) but are significantly smaller. However, the special properties of an extended system like a solid make it very easy to calculate the fundamental gap from the ground state (neutral system) band structure calculations entirely within a density functional framework. The correction Δ from the KS gap to the fundamental gap originates from the response part v resp of the exchange-correlation potential and can be calculated very simply using an approximation to v resp . This affords a calculation of the fundamental gap at the same level of accuracy as other properties of crystals at little extra cost beyond the ground state bandstructure calculation. The method is based on integer electron systems, fractional electron systems (an ensemble of N- and (N + 1)-electron systems) and the derivative discontinuity are not invoked.

Net alkalinity and net acidity 1: Theoretical considerations

Science.gov (United States)

Kirby, C.S.; Cravotta, C.A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined "CO 2-acidity" is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass- action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mg L -1 as CaCO3 (based on pH and analytical concentrations of dissolved FeII, FeIII, Mn, and Al in mg L -1):aciditycalculated=50{1000(10-pH)+[2(FeII)+3(FeIII)]/56+2(Mn)/ 55+3(Al)/27}underestimates contributions from HSO4- and H+, but overestimates the acidity due to Fe3+ and Al3+. However, these errors tend to approximately cancel each other. It is demonstrated that "net alkalinity" is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation, (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the value obtained in a

40 CFR 721.3821 - L-Glutamic acid, N-(1-oxododecyl)-.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false L-Glutamic acid, N-(1-oxododecyl... Substances § 721.3821 L-Glutamic acid, N-(1-oxododecyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as L-Glutamic acid, N-(1-oxododecyl)- (PMN P...

Reconstitution of the NF1 GAP-related domain in NF1-deficient human Schwann cells

International Nuclear Information System (INIS)

Thomas, Stacey L.; Deadwyler, Gail D.; Tang, Jun; Stubbs, Evan B.; Muir, David; Hiatt, Kelly K.; Clapp, D. Wade; De Vries, George H.

2006-01-01

Schwann cells derived from peripheral nerve sheath tumors from individuals with Neurofibromatosis Type 1 (NF1) are deficient for the protein neurofibromin, which contains a GAP-related domain (NF1-GRD). Neurofibromin-deficient Schwann cells have increased Ras activation, increased proliferation in response to certain growth stimuli, increased angiogenic potential, and altered cell morphology. This study examined whether expression of functional NF1-GRD can reverse the transformed phenotype of neurofibromin-deficient Schwann cells from both benign and malignant peripheral nerve sheath tumors. We reconstituted the NF1-GRD using retroviral transduction and examined the effects on cell morphology, growth potential, and angiogenic potential. NF1-GRD reconstitution resulted in morphologic changes, a 16-33% reduction in Ras activation, and a 53% decrease in proliferation in neurofibromin-deficient Schwann cells. However, NF1-GRD reconstitution was not sufficient to decrease the in vitro angiogenic potential of the cells. This study demonstrates that reconstitution of the NF1-GRD can at least partially reverse the transformation of human NF1 tumor-derived Schwann cells

5'Azido-N-1-napthylphthalamic acid, a photolabile analog of N-1-naphthylphthalamic acid

International Nuclear Information System (INIS)

Voet, J.G.; Howley, K.S.; Shumsky, J.S.

1987-01-01

A photolabile analog of N-1-naphthylphthalamic acid (NPA), 5'-azido-N-1-naphthylphthalamic acid (Az-NPA), has been synthesized and characterized. This potential photoaffinity label for the plasma membrane NPA binding protein competes with [ 3 H]NPA for binding sites on Curcurbita pepo L. (zucchini) hypocotyl cell membranes with K/sub 0.5/ = 2.8 x 10 -7 molar. The K/sub 0.5/ for NPA under these conditions is 2 x 10 -8 molar, indicating that the affinity of Az-NPA for the membranes is only 14-fold lower than NPA. While the binding of Az-NPA to NPA binding sites is reversible in the dark, exposure of the Az-NPA treated membranes to light results in a 30% loss in [ 3 H]NPA binding ability. Pretreatment of the membranes with NPA protects the membranes against photodestruction of [ 3 H]NPA binding sites by Az-NPA supporting the conclusion that Az-NPA destroys these sites by specific covalent attachment

START-GAP3/DLC3 is a GAP for RhoA and Cdc42 and is localized in focal adhesions regulating cell morphology

International Nuclear Information System (INIS)

Kawai, Katsuhisa; Kiyota, Minoru; Seike, Junichi; Deki, Yuko; Yagisawa, Hitoshi

2007-01-01

In the human genome there are three genes encoding RhoGAPs that contain the START (steroidogenic acute regulatory protein (StAR)-related lipid transfer)-domain. START-GAP3/DLC3 is a tumor suppressor gene similar to two other human START-GAPs known as DLC1 or DLC2. Although expression of START-GAP3/DLC3 inhibits the proliferation of cancer cells, its molecular function is not well understood. In this study we carried out biochemical characterization of START-GAP3/DLC3, and explored the effects of its expression on cell morphology and intracellular localization. We found that START-GAP3/DLC3 serves as a stimulator of PLCδ1 and as a GAP for both RhoA and Cdc42 in vitro. Moreover, we found that the GAP activity is responsible for morphological changes. The intracellular localization of endogenous START-GAP3/DLC3 was explored by immunocytochemistry and was revealed in focal adhesions. These results indicate that START-GAP3/DLC3 has characteristics similar to other START-GAPs and the START-GAP family seems to share common characteristics

No significant effect of the SLCO1B1 polymorphism on the pharmacokinetics of ursodeoxycholic acid.

Science.gov (United States)

Xiang, Xiaoqiang; Vakkilainen, Juha; Backman, Janne T; Neuvonen, Pertti J; Niemi, Mikko

2011-11-01

To investigate possible effects of the SLCO1B1 polymorphism on the pharmacokinetics of ursodeoxycholic acid (UDCA) and its metabolites in healthy volunteers. In a crossover study with two phases, 15 healthy volunteers with the SLCO1B1*1A/*1A genotype, seven with the *1B/*1B genotype, and five with the *15/*15 or *5/*15 genotype ingested placebo or a single 150-mg dose of UDCA. Plasma concentrations of bile acids and their biosynthesis marker were determined up to 24 h post-ingestion by liquid chromatography-tandem mass spectrometry. The SLCO1B1 genotype had no significant effect on the pharmacokinetics of UDCA. The geometric mean ratios (95% confidence interval) of UDCA area under the plasma concentration-time curve from 0 to 12 h (AUC(0-12)) in subjects with the SLCO1B1*1B/*1B genotype and in subjects with the SLCO1B1*15/*15 or *5/*15 genotype to the AUC(0-12) in subjects with the SLCO1B1*1A/*1A genotype were 1.07 (0.85, 1.35; P = 0.459) and 0.93 (0.75, 1.15; P = 0.563), respectively. In addition, following either placebo or UDCA administration, the SLCO1B1 polymorphism showed no association with the AUC(0-24) of the glycine and taurine conjugates of UDCA, with endogenous bile acids, or with the incremental AUC(0-24) of a bile acid synthesis marker. Compared with placebo, UDCA ingestion increased the AUC(0-24) of cholic acid, glycochenodeoxycholic acid, glycocholic acid, and glycodeoxycholic acid by 1.5-, 1.1-, 1.2-, and 1.2- fold (P acids.

Oleic acid and linoleic acid from Tenebrio molitor larvae inhibit BACE1 activity in vitro: molecular docking studies.

Science.gov (United States)

Youn, Kumju; Yun, Eun-Young; Lee, Jinhyuk; Kim, Ji-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

2014-02-01

In our ongoing research to find therapeutic compounds for Alzheimer's disease (AD) from natural resources, the inhibitory activity of the BACE1 enzyme by Tenebrio molitor larvae and its major compounds were evaluated. The T. molitor larvae extract and its fractions exhibited strong BACE1 suppression. The major components of hexane fraction possessing both high yield and strong BACE1 inhibition were determined by thin layer chromatography, gas chromatography, and nuclear magnetic resonance analysis. A remarkable composition of unsaturated long chain fatty acids, including oleic acid and linoleic acid, were identified. Oleic acid, in particular, noncompetitively attenuated BACE1 activity with a half-maximal inhibitory concentration (IC₅₀) value of 61.31 μM and Ki value of 34.3 μM. Furthermore, the fatty acids were stably interacted with BACE1 at different allosteric sites of the enzyme bound with the OH of CYS319 and the NH₃ of TYR320 for oleic acid and with the C=O group of GLN304 for linoleic acid. Here, we first revealed novel pharmacophore features of oleic acids and linoleic acid to BACE1 by in silico docking studies. The present findings would clearly suggest potential guidelines for designing novel BACE1 selective inhibitors.

Expedient Gap Definition Using 3D LADAR

Science.gov (United States)

2006-09-01

Research and Development Center (ERDC), ASI has developed an algorithm to reduce the 3D point cloud acquired with the LADAR system into sets of 2D...ATO IV.GC.2004.02. The GAP Program is conducted by the U.S. Army Engineer Research and Development Center (ERDC) in conjunction with the U.S. Army...Introduction 1 1 Introduction Background The Battlespace Gap Definition and Defeat ( GAP ) Program is conducted by the U.S. Army Engineer Research and

Biosynthesis of l-Ascorbic Acid and Conversion of Carbons 1 and 2 of l-Ascorbic Acid to Oxalic Acid Occurs within Individual Calcium Oxalate Crystal Idioblasts1

Science.gov (United States)

Kostman, Todd A.; Tarlyn, Nathan M.; Loewus, Frank A.; Franceschi, Vincent R.

2001-01-01

l-Ascorbic acid (AsA) and its metabolic precursors give rise to oxalic acid (OxA) found in calcium oxalate crystals in specialized crystal idioblast cells in plants; however, it is not known if AsA and OxA are synthesized within the crystal idioblast cell or transported in from surrounding mesophyll cells. Isolated developing crystal idioblasts from Pistia stratiotes were used to study the pathway of OxA biosynthesis and to determine if idioblasts contain the entire path and are essentially independent in OxA synthesis. Idioblasts were supplied with various 14C-labeled compounds and examined by micro-autoradiography for incorporation of 14C into calcium oxalate crystals. [14C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-14C]AsA also gave heavy labeling of crystals, whereas [6-14C]AsA gave no labeling. Labeled precursors of AsA (l-[1-14C]galactose; d-[1-14C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, d-[1-14C]erythorbic acid. Intensity of labeling of isolated idioblasts followed the pattern OxA > AsA (erythorbic acid) > l-galactose > d-mannose. Our results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, the OxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via d-mannose and l-galactose is operational in individual P. stratiotes crystal idioblasts. These results are discussed with respect to fine control of calcium oxalate precipitation and the concept of crystal idioblasts as independent physiological compartments. PMID:11161021

Cocrystals of the antimalarial drug 11-azaartemisinin with three alkenoic acids of 1:1 or 2:1 stoichiometry.

Science.gov (United States)

Nisar, Madiha; Wong, Lawrence W Y; Sung, Herman H Y; Haynes, Richard K; Williams, Ian D

2018-06-01

The stoichiometry, X-ray structures and stability of four pharmaceutical cocrystals previously identified from liquid-assisted grinding (LAG) of 11-azaartemisinin (11-Aza; systematic name: 1,5,9-trimethyl-14,15,16-trioxa-11-azatetracyclo[10.3.1.0 4,13 .0 8,13 ]hexadecan-10-one) with trans-cinnamic (Cin), maleic (Mal) and fumaric (Fum) acids are herein reported. trans-Cinnamic acid, a mono acid, forms 1:1 cocrystal 11-Aza:Cin (1, C 15 H 23 NO 4 ·C 9 H 8 O 2 ). Maleic acid forms both 1:1 cocrystal 11-Aza:Mal (2, C 15 H 23 NO 4 ·C 4 H 4 O 4 ), in which one COOH group is involved in self-catenation, and 2:1 cocrystal 11-Aza 2 :Mal (3, 2C 15 H 23 NO 4 ·C 4 H 4 O 4 ). Its isomer, fumaric acid, only affords 2:1 cocrystal 11-Aza 2 :Fum (4). All cocrystal formation appears driven by acid-lactam R 2 2 (8) heterosynthons with short O-H...O=C hydrogen bonds [O...O = 2.56 (2) Å], augmented by weaker C=O...H-N contacts. Despite a better packing efficiency, cocrystal 3 is metastable with respect to 2, probably due to a higher conformational energy for the maleic acid molecule in its structure. In each case, the microcrystalline powders from LAG were useful in providing seeding for the single-crystal growth.

Zero permeability and zero permittivity band gaps in 1D metamaterial photonic crystals

Energy Technology Data Exchange (ETDEWEB)

Depine, Ricardo A. [Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, C1428EHA Buenos Aires (Argentina); Martinez-Ricci, Maria L. [Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, C1428EHA Buenos Aires (Argentina); Monsoriu, Juan A. [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, 46022 Valencia (Spain)]. E-mail: jmonsori@fis.upv.es; Silvestre, Enrique [Departamento de Optica, Universidad de Valencia, 46100 Burjassot (Spain); Andres, Pedro [Departamento de Optica, Universidad de Valencia, 46100 Burjassot (Spain)

2007-04-30

We consider layered heterostructures combining ordinary positive index materials and dispersive metamaterials. We show that these structures can exhibit a new type of photonic gap around frequencies where either the magnetic permeability {mu} or the electric permittivity {epsilon} of the metamaterial is zero. Although the interface of a semi-infinite medium with zero refractive index (a condition attained either when {mu}=0 or when {epsilon}=0) is known to give full reflectivity for all incident polarizations, here we show that a gap corresponding to {mu}=0 occurs only for TE polarized waves, whereas a gap corresponding to {epsilon}=0 occurs only for TM polarized waves. These band gaps are scale-length invariant and very robust against disorder, although they may disappear for the particular case of propagation along the stratification direction.

Zero permeability and zero permittivity band gaps in 1D metamaterial photonic crystals

International Nuclear Information System (INIS)

Depine, Ricardo A.; Martinez-Ricci, Maria L.; Monsoriu, Juan A.; Silvestre, Enrique; Andres, Pedro

2007-01-01

We consider layered heterostructures combining ordinary positive index materials and dispersive metamaterials. We show that these structures can exhibit a new type of photonic gap around frequencies where either the magnetic permeability μ or the electric permittivity ε of the metamaterial is zero. Although the interface of a semi-infinite medium with zero refractive index (a condition attained either when μ=0 or when ε=0) is known to give full reflectivity for all incident polarizations, here we show that a gap corresponding to μ=0 occurs only for TE polarized waves, whereas a gap corresponding to ε=0 occurs only for TM polarized waves. These band gaps are scale-length invariant and very robust against disorder, although they may disappear for the particular case of propagation along the stratification direction

Dicty_cDB: Contig-U12316-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U12316-1 gap included 1238 4 1925901 1927143 PLUS 5 6 U12316 0 4 1 0 0 0 0 0 0 0 0 0 0 0 Show Contig...-U12316-1 Contig ID Contig-U12316-1 Contig update 2002.12.18 Contig sequence >Contig-U12316-1 (Contig-U12316-1Q) /CSM_Contig/Contig-U12316...GAGTTGAAGATTTAGTTTTATCAGNANGAANAAATAAGAT Gap gap included Contig length 1238 Chromosome number (1..6, M) 4 C...,915,1174 Translated Amino Acid sequence lvqhhyh*liscvivllksmv*isqvhivvhlfmfvn*qyileih*iptlknlskiftig...lip*r*rtrkttn*kiknny*itketkiqs*t*rvmmmi*vedlvls xxxnk Frame B: lvqhhyh*liscvivllksmv*isqvhivvhlfmfvn*qyileih*iptlknlskiftig

SynGAP regulates protein synthesis and homeostatic synaptic plasticity in developing cortical networks.

Directory of Open Access Journals (Sweden)

Chih-Chieh Wang

Full Text Available Disrupting the balance between excitatory and inhibitory neurotransmission in the developing brain has been causally linked with intellectual disability (ID and autism spectrum disorders (ASD. Excitatory synapse strength is regulated in the central nervous system by controlling the number of postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs. De novo genetic mutations of the synaptic GTPase-activating protein (SynGAP are associated with ID and ASD. SynGAP is enriched at excitatory synapses and genetic suppression of SynGAP increases excitatory synaptic strength. However, exactly how SynGAP acts to maintain synaptic AMPAR content is unclear. We show here that SynGAP limits excitatory synaptic strength, in part, by suppressing protein synthesis in cortical neurons. The data presented here from in vitro, rat and mouse cortical networks, demonstrate that regulation of translation by SynGAP involves ERK, mTOR, and the small GTP-binding protein Rheb. Furthermore, these data show that GluN2B-containing NMDARs and the cognitive kinase CaMKII act upstream of SynGAP and that this signaling cascade is required for proper translation-dependent homeostatic synaptic plasticity of excitatory synapses in developing cortical networks.

Formulation and properties of ADN/GAP propellants

Energy Technology Data Exchange (ETDEWEB)

Menke, Klaus; Heintz, Thomas; Schweikert, Wenka; Keicher, Thomas; Krause, Horst [Fraunhofer-Institut fuer Chemische Technologie ICT, Pfinztal (Germany)

2009-06-15

In this contribution two ways are described, how it is possible to achieve perfectly cured and processible propellants with prilled ADN, low amounts of HMX 5{mu}m mps and a binder system based on GAP diole and GAP triole oligomers with and without TMETN as a nitrate ester plasticizer. It was shown how it will be possible to suppress the strongly gas forming reaction between ADN and reactive isocyanates by a mixture of stabilizers. In this way it was possible to create minimum smoke ADN/HMX/GAP/TMETN propellants cured with the triisocyanate N100. In the second part an unconventional binder system based on the 1.3 dipolar cycloaddition reaction of azido groups with acetylene compounds forming 1,2,3-triazole heterocyclic rings has been applied for ADN/GAP and AP/GAP propellants. Together with small parts of HMX formulations with ADN/HMX/GAP and the corresponding AP/HMX/GAP exhibit high thermodynamic performance, are easily processible, and cure successfully at 60 C. Their basic properties consisting of burning behavior and mechanical properties, at ambient temperature, chemical stability, and sensitivity have been investigated and are compared to each other. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Parameters of radiation defects in GaP and GaAssub(1-x)Psub(x) with thermostimulated current measurements

International Nuclear Information System (INIS)

Brajlovskij, E.Yu.; Marchuk, N.D.

1980-01-01

Introduction of point defects in gallium phosphide crystals and GaAssub(1-x)Psub(x) solid solutions under the action of 1 MeV electrons is studied by TSC method on Schottky barriers. The TSC spectra processing using the computer is given. In GaP crystals the dominant electron and hole traps are D-centers (Esub(c)-1.24 eV) and M-centers (Esub(v)+1.43 eV). The received level spectrum explains the compensation of conductivity of n- and p-lGaP under irradiation. It is shown that main defects observed in electron irradiated GaP are most likely phosphorus vacancies (D-center)and gallium vacancies (M-center)

Forbidden energy band gap in diluted a-Ge1−xSix:N films

International Nuclear Information System (INIS)

Guarneros, C.; Rebollo-Plata, B.; Lozada-Morales, R.; Espinosa-Rosales, J.E.; Portillo-Moreno, J.; Zelaya-Angel, O.

2012-01-01

By means of electron gun evaporation Ge 1−x Si x :N thin films, in the entire range 0 ≤ x ≤ 1, were prepared on Si (100) and glass substrates. The initial vacuum reached was 6.6 × 10 −4 Pa, then a pressure of 2.7 × 10 −2 Pa of high purity N 2 was introduced into the chamber. The deposition time was 4 min. Crucible-substrate distance was 18 cm. X-ray diffraction patterns indicate that all the films were amorphous (a-Ge 1−x Si x :N). The nitrogen concentration was of the order of 1 at% for all the films. From optical absorption spectra data and by using the Tauc method the energy band gap (E g ) was calculated. The Raman spectra only reveal the presence of Si-Si, Ge-Ge, and Si-Ge bonds. Nevertheless, infrared spectra demonstrate the existence of Si-N and Ge-N bonds. The forbidden energy band gap (E g ) as a function of x in the entire range 0 ≤ x ≤ 1 shows two well defined regions: 0 ≤ x ≤ 0.67 and 0.67 ≤ x ≤ 1, due to two different behaviors of the band gap, where for x > 0.67 exists an abruptly change of E g (x). In this case E g (x) versus x is different to the variation of E g in a-Ge 1−x Si x and a-Ge 1−x Si x :H. This fact can be related to the formation of Ge 3 N 4 and GeSi 2 N 4 when x ≤ 0.67, and to the formation of Si 3 N 4 and GeSi 2 N 4 for 0.67 ≤ x. - Highlights: ► Nitrogen doped amorphous Ge 1-x Si x thin films are grown by electron gun technique. ► Nitrogen atoms on E g of the a-Ge 1-x Si x films in the 0 £ x £ 1 range are analyzed. ► Variation in 0 £ x £ 1 range shows a warped change of E g in 1.0 – 3.6 eV range. ► The change in E g (x) behavior when x ∼ 0.67 was associated with Ge 2 SiN 4 presence.

Modeling charged defects inside density functional theory band gaps

International Nuclear Information System (INIS)

Schultz, Peter A.; Edwards, Arthur H.

2014-01-01

Density functional theory (DFT) has emerged as an important tool to probe microscopic behavior in materials. The fundamental band gap defines the energy scale for charge transition energy levels of point defects in ionic and covalent materials. The eigenvalue gap between occupied and unoccupied states in conventional DFT, the Kohn–Sham gap, is often half or less of the experimental band gap, seemingly precluding quantitative studies of charged defects. Applying explicit and rigorous control of charge boundary conditions in supercells, we find that calculations of defect energy levels derived from total energy differences give accurate predictions of charge transition energy levels in Si and GaAs, unhampered by a band gap problem. The GaAs system provides a good theoretical laboratory for investigating band gap effects in defect level calculations: depending on the functional and pseudopotential, the Kohn–Sham gap can be as large as 1.1 eV or as small as 0.1 eV. We find that the effective defect band gap, the computed range in defect levels, is mostly insensitive to the Kohn–Sham gap, demonstrating it is often possible to use conventional DFT for quantitative studies of defect chemistry governing interesting materials behavior in semiconductors and oxides despite a band gap problem

Site-directed Mutagenesis Shows the Significance of Interactions with Phospholipids and the G-protein OsYchF1 for the Physiological Functions of the Rice GTPase-activating Protein 1 (OsGAP1).

Science.gov (United States)

Yung, Yuk-Lin; Cheung, Ming-Yan; Miao, Rui; Fong, Yu-Hang; Li, Kwan-Pok; Yu, Mei-Hui; Chye, Mee-Len; Wong, Kam-Bo; Lam, Hon-Ming

2015-09-25

The C2 domain is one of the most diverse phospholipid-binding domains mediating cellular signaling. One group of C2-domain proteins are plant-specific and are characterized by their small sizes and simple structures. We have previously reported that a member of this group, OsGAP1, is able to alleviate salt stress and stimulate defense responses, and bind to both phospholipids and an unconventional G-protein, OsYchF1. Here we solved the crystal structure of OsGAP1 to a resolution of 1.63 Å. Using site-directed mutagenesis, we successfully differentiated between the clusters of surface residues that are required for binding to phospholipids versus OsYchF1, which, in turn, is critical for its role in stimulating defense responses. On the other hand, the ability to alleviate salt stress by OsGAP1 is dependent only on its ability to bind OsYchF1 and is independent of its phospholipid-binding activity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Enhanced anti-HIV-1 activity of G-quadruplexes comprising locked nucleic acids and intercalating nucleic acids

DEFF Research Database (Denmark)

Pedersen, Erik Bjerregaard; Nielsen, Jakob Toudahl; Nielsen, Claus

2011-01-01

Two G-quadruplex forming sequences, 50-TGGGAG and the 17-mer sequence T30177, which exhibit anti-HIV-1 activity on cell lines, were modified using either locked nucleic acids (LNA) or via insertions of (R)-1-O-(pyren-1-ylmethyl)glycerol (intercalating nucleic acid, INA) or (R)-1-O-[4-(1......-pyrenylethynyl)phenylmethyl]glycerol (twisted intercalating nucleic acid, TINA). Incorporation of LNA or INA/TINA monomers provide as much as 8-fold improvement of anti-HIV-1 activity. We demonstrate for the first time a detailed analysis of the effect the incorporation of INA/TINA monomers in quadruplex forming...

Electron Elevator: Excitations across the Band Gap via a Dynamical Gap State.

Science.gov (United States)

Lim, A; Foulkes, W M C; Horsfield, A P; Mason, D R; Schleife, A; Draeger, E W; Correa, A A

2016-01-29

We use time-dependent density functional theory to study self-irradiated Si. We calculate the electronic stopping power of Si in Si by evaluating the energy transferred to the electrons per unit path length by an ion of kinetic energy from 1 eV to 100 keV moving through the host. Electronic stopping is found to be significant below the threshold velocity normally identified with transitions across the band gap. A structured crossover at low velocity exists in place of a hard threshold. An analysis of the time dependence of the transition rates using coupled linear rate equations enables one of the excitation mechanisms to be clearly identified: a defect state induced in the gap by the moving ion acts like an elevator and carries electrons across the band gap.

Experimental study on in-vessel debris coolability during severe accident - Experimental and analytical model study on gap cooling in gap

Energy Technology Data Exchange (ETDEWEB)

Chang, Soon Heung; Baek, Won Pil; Yang, Soo Hyung; Kim, Soo Hyoung; Lee, Yong Ho; Chung, Yong Hun [Korea Advanced Institute of Science and Technology, Taejon (Korea)

1999-04-01

To understand the flooding and mechanism in gap geometry, research was conducted. Final objectives of research are as follows: 1) Literature survey of the flooding and heat transfer mechanism in gap geometry 2) Performing CHF experiments using bottom closed rectangular channels test section 3) Development of flooding correlation using flooding data 4) Derive instability wave length in narrow gap. The major results of research are as follows: 1) Gap size and span of channel are important parameter for flooding. 2) Kutateladze number used for analysing flooding data, is appropriate to the analysis of the flooding using non-circular narrow gap channel. 3) Flooding correlation was developed using collected flooding data and it predicts flooding data lower than 10%. 4) CHF correlation derived from developed flooding collreation overpredict CHF. 5) Instability wave length is increased as gap size is decreased. 26 refs., 46 figs., 2 tabs. (Author)

Crystal structures of three co-crystals of 1,2-bis-(pyridin-4-yl)ethane with 4-alk-oxy-benzoic acids: 4-eth-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), 4-n-propoxybenzoic acid-1,2-bis(pyridin-4-yl)ethane (2/1) and 4-n-but-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1).

Science.gov (United States)

Tabuchi, Yohei; Gotoh, Kazuma; Ishida, Hiroyuki

2015-11-01

The crystal structures of three hydrogen-bonded co-crystals of 4-alk-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), namely, 2C9H10O3·C12H12N2, (I), 2C10H12O3·C12H12N2, (II), and 2C11H14O3·C12H12N2, (III), have been determined at 93, 290 and 93 K, respectively. In (I), the asymmetric unit consists of one 4-eth-oxy-benzoic acid mol-ecule and one half-mol-ecule of 1,2-bis-(pyridin-4-yl)ethane, which lies on an inversion centre. In (II) and (III), the asymmetric units each comprise two crystallographically independent 4-alk-oxy-benzoic acid mol-ecules and one 1,2-bis-(pyridin-4-yl)ethane mol-ecule. In each crystal, the two components are linked by O-H⋯N hydrogen bonds, forming a linear hydrogen-bonded 2:1unit of the acid and the base. Similar to the structure of 2:1 unit of (I), the units of (II) and (III) adopt nearly pseudo-inversion symmetry. The 2:1 units of (I), (II) and (III) are linked via C-H⋯O hydrogen bonds, forming tape structures.

Crystal structure of [1,1':3',1''-ter-phenyl]-2',3,3''-tri-carb-oxy-lic acid.

Science.gov (United States)

Decato, Daniel A; Berryman, Orion B

2015-09-01

The asymmetric unit of the title compound, C21H14O6, com-prises two symmetrically independent mol-ecules that form a locally centrosymmetric hydrogen-bonded dimer, with the planes of the corresponding carb-oxy-lic acid groups rotated by 15.8 (1) and 17.5 (1)° relative to those of the adjacent benzene rings. The crystal as a whole, however, exhibits a noncentrosymmetric packing, described by the polar space group Pca21. The dimers form layers along the ab plane, being inter-connected by hydrogen bonds involving the remaining carb-oxy-lic acid groups. The plane of the central carb-oxy-lic acid group forms dihedral angles of 62.5 (1) and 63.0 (1)° with those of the adjacent benzene rings and functions as a hydrogen-bond donor and acceptor. As a donor, it inter-connects adjacent layers, while as an acceptor it stabilizes the packing within the layers. The 'distal' carb-oxy-lic acid groups are nearly coplanar with the planes of the adjacent benzene rings, forming dihedral angles of 1.8 (1) and 7.1 (1)°. These groups also form intra- and inter-layer hydrogen bonds, but with 'reversed' functionality, as compared with the central carb-oxy-lic acid groups.

Agdc1p – a Gallic Acid Decarboxylase Involved in the Degradation of Tannic Acid in the Yeast Blastobotrys (Arxula adeninivorans

Directory of Open Access Journals (Sweden)

Anna K. Meier

2017-09-01

Full Text Available Tannins and hydroxylated aromatic acids, such as gallic acid (3,4,5-trihydroxybenzoic acid, are plant secondary metabolites which protect plants against herbivores and plant-associated microorganisms. Some microbes, such as the yeast Arxula adeninivorans are resistant to these antimicrobial substances and are able to use tannins and gallic acid as carbon sources. In this study, the Arxula gallic acid decarboxylase (Agdc1p which degrades gallic acid to pyrogallol was characterized and its function in tannin catabolism analyzed. The enzyme has a higher affinity for gallic acid (Km −0.7 ± 0.2 mM, kcat −42.0 ± 8.2 s−1 than to protocatechuic acid (3,4-dihydroxybenzoic acid (Km −3.2 ± 0.2 mM, kcat −44.0 ± 3.2 s−1. Other hydroxylated aromatic acids, such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid are not gallic acid decarboxylase substrates. A. adeninivorans G1212/YRC102-AYNI1-AGDC1, which expresses the AGDC1 gene under the control of the strong nitrate inducible AYNI1 promoter achieved a maximum gallic acid decarboxylase activity of 1064.4 U/l and 97.5 U/g of dry cell weight in yeast grown in minimal medium with nitrate as nitrogen source and glucose as carbon source. In the same medium, gallic acid decarboxylase activity was not detected for the control strain G1212/YRC102 with AGDC1 expression under the control of the endogenous promoter. Gene expression analysis showed that AGDC1 is induced by gallic acid and protocatechuic acid. In contrast to G1212/YRC102-AYNI1-AGDC1 and G1212/YRC102, A. adeninivorans G1234 [Δagdc1] is not able to grow on medium with gallic acid as carbon source but can grow in presence of protocatechuic acid. This confirms that Agdc1p plays an essential role in the tannic acid catabolism and could be useful in the production of catechol and cis,cis-muconic acid. However, the protocatechuic acid catabolism via Agdc1p to

Agdc1p – a Gallic Acid Decarboxylase Involved in the Degradation of Tannic Acid in the Yeast Blastobotrys (Arxula) adeninivorans

Science.gov (United States)

Meier, Anna K.; Worch, Sebastian; Böer, Erik; Hartmann, Anja; Mascher, Martin; Marzec, Marek; Scholz, Uwe; Riechen, Jan; Baronian, Kim; Schauer, Frieder; Bode, Rüdiger; Kunze, Gotthard

2017-01-01

Tannins and hydroxylated aromatic acids, such as gallic acid (3,4,5-trihydroxybenzoic acid), are plant secondary metabolites which protect plants against herbivores and plant-associated microorganisms. Some microbes, such as the yeast Arxula adeninivorans are resistant to these antimicrobial substances and are able to use tannins and gallic acid as carbon sources. In this study, the Arxula gallic acid decarboxylase (Agdc1p) which degrades gallic acid to pyrogallol was characterized and its function in tannin catabolism analyzed. The enzyme has a higher affinity for gallic acid (Km −0.7 ± 0.2 mM, kcat −42.0 ± 8.2 s−1) than to protocatechuic acid (3,4-dihydroxybenzoic acid) (Km −3.2 ± 0.2 mM, kcat −44.0 ± 3.2 s−1). Other hydroxylated aromatic acids, such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid are not gallic acid decarboxylase substrates. A. adeninivorans G1212/YRC102-AYNI1-AGDC1, which expresses the AGDC1 gene under the control of the strong nitrate inducible AYNI1 promoter achieved a maximum gallic acid decarboxylase activity of 1064.4 U/l and 97.5 U/g of dry cell weight in yeast grown in minimal medium with nitrate as nitrogen source and glucose as carbon source. In the same medium, gallic acid decarboxylase activity was not detected for the control strain G1212/YRC102 with AGDC1 expression under the control of the endogenous promoter. Gene expression analysis showed that AGDC1 is induced by gallic acid and protocatechuic acid. In contrast to G1212/YRC102-AYNI1-AGDC1 and G1212/YRC102, A. adeninivorans G1234 [Δagdc1] is not able to grow on medium with gallic acid as carbon source but can grow in presence of protocatechuic acid. This confirms that Agdc1p plays an essential role in the tannic acid catabolism and could be useful in the production of catechol and cis,cis-muconic acid. However, the protocatechuic acid catabolism via Agdc1p to catechol seems to be

Regulation of Auxin Homeostasis and Gradients in Arabidopsis Roots through the Formation of the Indole-3-Acetic Acid Catabolite 2-Oxindole-3-Acetic Acid

Czech Academy of Sciences Publication Activity Database

Pěnčík, A.; Simonovik, B.; Petersson, S.V.; Hényková, Eva; Simon, Sibu; Greenham, K.; Zhang, Y.; Kowalczyk, M.; Estelle, M.; Zažímalová, Eva; Novák, Ondřej; Sandberg, G.; Ljung, K.

2013-01-01

Roč. 25, č. 10 (2013), s. 3858-3870 ISSN 1040-4651 R&D Projects: GA ČR(CZ) GAP305/11/0797 Institutional research plan: CEZ:AV0Z50380511 Keywords : BOX PROTEIN TIR1 * PLANT DEVELOPMENT * OXINDOLE-3-ACETIC ACID Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.575, year: 2013

Thermochemistry of 1,3-diethylbarbituric and 1,3-diethyl-2-thiobarbituric acids: Experimental and computational study

International Nuclear Information System (INIS)

Notario, Rafael; Roux, María Victoria; Ros, Francisco; Emel’yanenko, Vladimir N.; Zaitsau, Dzmitry H.; Verevkin, Sergey P.

2014-01-01

Highlights: • Enthalpies of formation in condensed phase have been obtained. • Enthalpy of vaporization of 1,3-diethylbarbituric acid has been determined. • Enthalpy of sublimation of 1,3-diethyl-2-thiobarbituric acid has been determined. • Gas-phase enthalpies of formation have been obtained. • Gas-phase enthalpies of formation have been calculated at G3 and G4 levels. - Abstract: This paper reports an experimental and computational thermochemical study on two barbituric acid derivatives, viz. 1,3-diethylbarbituric acid and 1,3-diethyl-2-thiobarbituric acid. Values of standard molar enthalpies of formation in the gas phase at T = 298.15 K have been derived from experiment. Energies of combustion were measured by the static bomb combustion calorimetry in the case of 1,3-diethylbarbituric acid, and the rotating-bomb combustion calorimetry in the case of 1,3-diethyl-2-thiobarbituric acid. From the combustion energies, standard molar enthalpies of formation in the crystalline state at T = 298.15 K were calculated. The enthalpy of vaporization of 1,3-diethylbarbituric acid and enthalpy of sublimation of 1,3-diethyl-2-thiobarbituric acid were determined using the transpiration method. Combining calorimetric and transpiration results, values of −(611.9 ± 2.0) kJ · mol −1 and −(343.8 ± 2.2) kJ · mol −1 for the gas-phase enthalpies of formation at T = 298.15 K of 1,3-diethylbarbituric and 1,3-diethyl-2-thiobarbituric acids, respectively, were derived. Theoretical calculations at the G3 and G4 levels were performed, and a study of the molecular structure of the compounds has been carried out. Calculated enthalpies of formation were in very good agreement with the experimental values

On the Feasibility of Gap Detection of Power Transformer Partial Discharge UHF Signals: Gap Propagation Characteristics of Electromagnetic Waves

Directory of Open Access Journals (Sweden)

Xiaoxing Zhang

2017-10-01

Full Text Available This study analyzed the transformer electromagnetic gap propagation characteristics. The influence of gap size is also analyzed, and the results experimentally verified. The obtained results indicated that the gap propagation characteristics of electromagnetic wave signals radiated by the partial discharge (PD source in different directions are substantially different. The intensity of the electromagnetic wave in the gap reaches a maximum at a gap height of 1 cm; and inside the gap, the intensity of the electromagnetic wave depicted an increasing trend at the tail area of the gap. Finally, from the obtained results, some suggestions on where to install sensors in practical systems for ultra high frequency (UHF PD signal detection in the transformer gap are provided. The obtained results confirmed the feasibility of using this approach. These results can be seen as a benchmark and a challenge for further research in this field.

How empty are disk gaps opened by giant planets?

Energy Technology Data Exchange (ETDEWEB)

Fung, Jeffrey [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Shi, Ji-Ming; Chiang, Eugene, E-mail: fung@astro.utoronto.ca [Department of Astronomy, UC Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411 (United States)

2014-02-20

Gap clearing by giant planets has been proposed to explain the optically thin cavities observed in many protoplanetary disks. How much material remains in the gap determines not only how detectable young planets are in their birth environments, but also how strong co-rotation torques are, which impacts how planets can survive fast orbital migration. We determine numerically how the average surface density inside the gap, Σ{sub gap}, depends on planet-to-star mass ratio q, Shakura-Sunyaev viscosity parameter α, and disk height-to-radius aspect ratio h/r. Our results are derived from our new graphics processing unit accelerated Lagrangian hydrodynamical code PEnGUIn and are verified by independent simulations with ZEUS90. For Jupiter-like planets, we find Σ{sub gap}∝q {sup –2.2}α{sup 1.4}(h/r){sup 6.6}, and for near brown dwarf masses, Σ{sub gap}∝q {sup –1}α{sup 1.3}(h/r){sup 6.1}. Surface density contrasts inside and outside gaps can be as large as 10{sup 4}, even when the planet does not accrete. We derive a simple analytic scaling, Σ{sub gap}∝q {sup –2}α{sup 1}(h/r){sup 5}, that compares reasonably well to empirical results, especially at low Neptune-like masses, and use discrepancies to highlight areas for progress.

A Putative ABC Transporter Permease Is Necessary for Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa under Aerobic and Anaerobic Planktonic and Biofilm Conditions.

Science.gov (United States)

McDaniel, Cameron; Su, Shengchang; Panmanee, Warunya; Lau, Gee W; Browne, Tristan; Cox, Kevin; Paul, Andrew T; Ko, Seung-Hyun B; Mortensen, Joel E; Lam, Joseph S; Muruve, Daniel A; Hassett, Daniel J

2016-01-01

Pseudomonas aeruginosa (PA) is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite ([Formula: see text], pH 6.5) at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to [Formula: see text]. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to [Formula: see text], but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with [Formula: see text] plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM [Formula: see text], and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to [Formula: see text] in biofilms. [Formula: see text] sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM) that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, [Formula: see text] as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.

Thermo-Structural Response Caused by Structure Gap and Gap Design for Solid Rocket Motor Nozzles

Directory of Open Access Journals (Sweden)

Lin Sun

2016-06-01

Full Text Available The thermo-structural response of solid rocket motor nozzles is widely investigated in the design of modern rockets, and many factors related to the material properties have been considered. However, little work has been done to evaluate the effects of structure gaps on the generation of flame leaks. In this paper, a numerical simulation was performed by the finite element method to study the thermo-structural response of a typical nozzle with consideration of the structure gap. Initial boundary conditions for thermo-structural simulation were defined by a quasi-1D model, and then coupled simulations of different gap size matching modes were conducted. It was found that frictional interface treatment could efficiently reduce the stress level. Based on the defined flame leak criteria, gap size optimization was carried out, and the best gap matching mode was determined for designing the nozzle. Testing experiment indicated that the simulation results from the proposed method agreed well with the experimental results. It is believed that the simulation method is effective for investigating thermo-structural responses, as well as designing proper gaps for solid rocket motor nozzles.

Low-Symmetry Gap Functions of Organic Superconductors

Science.gov (United States)

Mori, Takehiko

2018-04-01

Superconducting gap functions of various low-symmetry organic superconductors are investigated starting from the tight-binding energy band and the random phase approximation by numerically solving Eliashberg's equation. The obtained singlet gap function is approximately represented by an asymmetrical dx2 - y2 form, where two cosine functions are mixed in an appropriate ratio. This is usually called d + s wave, where the ratio of the two cosine functions varies from 1:1 in the two-dimensional limit to 1:0 in the one-dimensional limit. A single cosine function does not make a superconducting gap in an ideal one-dimensional conductor, but works as a relevant gap function in quasi-one-dimensional conductors with slight interchain transfer integrals. Even when the Fermi surface is composed of small pockets, the gap function is obtained supposing a globally connected elliptical Fermi surface. In such a case, we have to connect the second energy band in the second Brillouin zone. The periodicity of the resulting gap function is larger than the first Brillouin zone. This is because the susceptibility has peaks at 2kF, where the periodicity has to be twice the size of the global Fermi surface. In general, periodicity of gap function corresponds to one electron or two molecules in the real space. In the κ-phase, two axes are nonequivalent, but the exact dx2 - y2 symmetry is maintained because the diagonal transfer integral introduced to a square lattice is oriented to the node direction of the dx2 - y2 wave. By contrast, the θ-phase gap function shows considerable anisotropy because a quarter-filled square lattice has a different dxy symmetry.

Acid-base disorders in calves with chronic diarrhea.

Science.gov (United States)

Bednarski, M; Kupczyński, R; Sobiech, P

2015-01-01

The aim of this study was to analyze disorders of acid-base balance in calves with chronic diarrhea caused by mixed, viral, bacterial and Cryptosporydium parvum infection. We compared results ob- tained with the classic model (Henderson-Hasselbalch) and strong ion approach (the Steward model). The study included 36 calves aged between 14 and 21 days. The calves were allocated to three groups: I - (control) non-diarrheic calves, group II - animals with compensated acid-base imbalance and group III calves with compensated acid-base disorders and hypoalbuminemia. Plasma concentrations of Na+, K+, Cl-, C12+, Mg2+, P, albumin and lactate were measured. In the classic model, acid-base balance was determined on the basis of blood pH, pCO2, HCO3-, BE and anion gap. In the strong ion model, strong ion difference (SID), effective strong anion difference, total plasma concentration of nonvolatile buffers (A(Tot)) and strong ion gap (SIG) were measured. The control calves and the animals from groups II and III did not differ significantly in terms of their blood pH. The plasma concentration of HCO3-, BE and partial pressure of CO2 in animals from the two groups with chronic diarrhea were significantly higher than those found in the controls. The highest BE (6.03 mmol/l) was documented in calves from group II. The animals from this group presented compensation resulted from activation of metabolic mechanisms. The calves with hypoal- buminemia (group III) showed lower plasma concentrations of albumin (15.37 g/L), Cl (74.94 mmol/L), Mg2+ (0.53 mmol/L), P (1.41 mmol/L) and higher value of anion gap (39.03 mmol/L). This group III presented significantly higher SID3 (71.89 mmol/L), SID7 (72.92 mmol/L) and SIG (43.53 mmol/L) values than animals from the remaining groups (P acid-base disturbance in these cases suggests that classic model have some limitations. This model can not be recommended for use whenever serum albumin or phosphate concentrations are markedly abnormal.

Green synthesis of low-toxicity graphene-fulvic acid with an open band gap enhances demethylation of methylmercury.

Science.gov (United States)

Hu, Xiangang; Mu, Li; Lu, Kaicheng; Kang, Jia; Zhou, Qixing

2014-06-25

The demethylation of methylmercury has received substantial attention. Here, a novel chemical method for the demethylation of methylmercury is proposed. The low-toxicity graphene-fulvic acid (FA, a ubiquitous material in the environment) was synthesized without the use of a chemical reagent. The hybridized graphene-FA presented an indirect open band gap of 2.25-2.87 eV as well as adequate aqueous dispersion. More importantly, the hybridized graphene-FA exhibited 6- and 10-fold higher photocatalytic efficiencies for the demethylation of methylmercury than FA and free FA with graphene, respectively. This result implies that immobilized, rather than free, FA accelerated the catalysis. Furthermore, inorganic mercuric ion, elemental mercury, and mercuric oxide were identified as the primary demethylation products. For free FA with graphene, graphene quenches the excited-state FA, inhibiting the demethylation by electron transfer. In contrast, the graphene of the self-assembled graphene-FA serves as an electron reservoir, causing electron-hole pair separation. Graphene-FA showed a negligible toxicity toward microalgae compared to graphene. The above results reveal that the green synthesis of graphene and organic molecules is a convenient strategy for obtaining effective cocatalysts.

The synthesis of phosphonic acids derived from homocysteine via transesterification reactions

Czech Academy of Sciences Publication Activity Database

Pícha, Jan; Buděšínský, Miloš; Fiedler, Pavel; Jiráček, Jiří

-, č. 4 (2012), s. 80-99 ISSN 1551-7004 R&D Projects: GA ČR(CZ) GAP207/10/1277; GA ČR GA203/09/1919 Institutional research plan: CEZ:AV0Z40550506 Keywords : phosphonohomocysteine * aminophosphonic acids Subject RIV: CC - Organic Chemistry Impact factor: 1.057, year: 2012

SUMO modification through rapamycin-mediated heterodimerization reveals a dual role for Ubc9 in targeting RanGAP1 to nuclear pore complexes

International Nuclear Information System (INIS)

Zhu Shanshan; Zhang Hong; Matunis, Michael J.

2006-01-01

SUMOs (small ubiquitin-related modifiers) are eukaryotic proteins that are covalently conjugated to other proteins and thereby regulate a wide range of important cellular processes. The molecular mechanisms by which SUMO modification influences the functions of most target proteins and cellular processes, however, remain poorly defined. A major obstacle to investigating the effects of SUMO modification is the availability of a system for selectively inducing the modification or demodification of an individual protein. To address this problem, we have developed a procedure using the rapamycin heterodimerizer system. This procedure involves co-expression of rapamycin-binding domain fusion proteins of SUMO and candidate SUMO substrates in living cells. Treating cells with rapamycin induces a tight association between SUMO and a single SUMO substrate, thereby allowing specific downstream effects to be analyzed. Using RanGAP1 as a model SUMO substrate, the heterodimerizer system was used to investigate the molecular mechanism by which SUMO modification targets RanGAP1 from the cytoplasm to nuclear pore complexes (NPCs). Our results revealed a dual role for Ubc9 in targeting RanGAP1 to NPCs: In addition to conjugating SUMO-1 to RanGAP1, Ubc9 is also required to form a stable ternary complex with SUMO-1 modified RanGAP1 and Nup358. As illustrated by our studies, the rapamycin heterodimerizer system represents a novel tool for studying the molecular effects of SUMO modification

Self-Assembled Nanoparticles of Glycyrrhetic Acid-Modified Pullulan as a Novel Carrier of Curcumin

Directory of Open Access Journals (Sweden)

Roufen Yuan

2014-08-01

Full Text Available Glycyrrhetic acid (GA-modified pullulan nanoparticles (GAP NPs were synthesized as a novel carrier of curcumin (CUR with a degree of substitution (DS of GA moieties within the range of 1.2–6.2 groups per hundred glucose units. In the present study, we investigated the physicochemical characteristics, release behavior, in vitro cytotoxicity and cellular uptake of the particles. Self-assembled GAP NPs with spherical shapes could readily improve the water solubility and stability of CUR. The CUR release was sustained and pH-dependent. The cellular uptake of CUR-GAP NPs was confirmed by green fluorescence in the cells. An MTT study showed CUR-GAP NPs with higher cytotoxicity in HepG2 cells than free CUR, but GAP NPs had no significant cytotoxicity. GAP is thus an excellent carrier for the solubilization, stabilization, and controlled delivery of CUR.

The exact mass-gap of the supersymmetric CP$^{N-1}$ sigma model

CERN Document Server

Evans, J M; Evans, Jonathan M; Hollowood, Timothy J

1995-01-01

A formula for the mass-gap of the supersymmetric \\CP^{n-1} sigma model (n > 1) in two dimensions is derived: m/\\Lambda_{\\overline{\\rm MS}}=\\sin(\\pi\\Delta)/(\\pi\\Delta) where \\Delta=1/n and m is the mass of the fundamental particle multiplet. This result is obtained by comparing two expressions for the free-energy density in the presence of a coupling to a conserved charge; one expression is computed from the exact S-matrix of K\\"oberle and Kurak via the thermodynamic Bethe ansatz and the other is computed using conventional perturbation theory. These calculations provide a stringent test of the S-matrix, showing that it correctly reproduces the universal part of the beta-function and resolving the problem of CDD ambiguities.

Decomposition and detoxification of aflatoxin B1 by lactic acid.

Science.gov (United States)

Aiko, Visenuo; Edamana, Prasad; Mehta, Alka

2016-04-01

A degradation study of aflatoxin B1 (AFB1) was carried out using a combination of physical and chemical methods. AFB1 was heated at 80 °C in the presence of acetic, citric and lactic acids for various time periods. The cytotoxicity of the degraded AFB1 and its products were determined by MTT assay. The results showed that among the three organic acids lactic acid was most efficient in degrading AFB1. Although complete degradation was not observed, up to 85% degradation of AFB1 was obtained when heated for 120 min. Degradation of AFB1 was confirmed by the reduced toxicity on HeLa cells using MTT assay. Treatment with lactic acid resulted in the conversion of AFB1 into two degradation products. These products were observed at lower retention factors of 0.63 and 0.38, which were identified as AFB2 and AFB2a, respectively. The cytotoxicity of AFB2a exhibited much reduced toxicity on HeLa cells compared to that of AFB1. The results have shown the efficiency of lactic acid in degrading AFB1. This study suggest that lactic acid may be considered for use in the food and feed industry since it is present naturally in food and is considered safe. © 2015 Society of Chemical Industry.

Strong Quantum Confinement Effects and Chiral Excitons in Bio-Inspired ZnO–Amino Acid Cocrystals

KAUST Repository

Muhammed, Madathumpady Abubaker Habeeb

2018-02-20

Elucidating the underlying principles behind band gap engineering is paramount for the successful implementation of semiconductors in photonic and optoelectronic devices. Recently it has been shown that the band gap of a wide and direct band gap semiconductor, such as ZnO, can be modified upon cocrystallization with amino acids, with the role of the biomolecules remaining unclear. Here, by probing and modeling the light-emitting properties of ZnO-amino acid cocrystals, we identify the amino acids\\' role on this band gap modulation and demonstrate their effective chirality transfer to the interband excitations in ZnO. Our 3D quantum model suggests that the strong band edge emission blue-shift in the cocrystals can be explained by a quasi-periodic distribution of amino acid potential barriers within the ZnO crystal lattice. Overall, our findings indicate that biomolecule cocrystallization can be used as a truly bio-inspired means to induce chiral quantum confinement effects in quasi-bulk semiconductors.

2-Aminobenzoic acid–4-(pyridin-4-yldisulfanyl)pyridine (1/1)

OpenAIRE

Hadi D. Arman; Trupta Kaulgud; Edward R. T. Tiekink

2011-01-01

The title 1:1 co-crystal, C7H7NO2·C10H8N2S2, features a highly twisted 4-(pyridin-4-yldisulfanyl)pyridine molecule [dihedral angle between the pyridine rings = 89.06 (10)°]. A small twist is evident in the 2-aminobenzoic acid molecule, with the C—C—C—O torsion angle being −7.7 (3)°. An N—H...O hydrogen bond occurs in the 2-aminobenzoic acid molecule. In the crystal, molecules are linked by O&#...

Dynamin-dependent amino acid endocytosis activates mechanistic target of rapamycin complex 1 (mTORC1).

Science.gov (United States)

Shibutani, Shusaku; Okazaki, Hana; Iwata, Hiroyuki

2017-11-03

The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of protein synthesis and potential target for modifying cellular metabolism in various conditions, including cancer and aging. mTORC1 activity is tightly regulated by the availability of extracellular amino acids, and previous studies have revealed that amino acids in the extracellular fluid are transported to the lysosomal lumen. There, amino acids induce recruitment of cytoplasmic mTORC1 to the lysosome by the Rag GTPases, followed by mTORC1 activation by the small GTPase Ras homolog enriched in brain (Rheb). However, how the extracellular amino acids reach the lysosomal lumen and activate mTORC1 remains unclear. Here, we show that amino acid uptake by dynamin-dependent endocytosis plays a critical role in mTORC1 activation. We found that mTORC1 is inactivated when endocytosis is inhibited by overexpression of a dominant-negative form of dynamin 2 or by pharmacological inhibition of dynamin or clathrin. Consistently, the recruitment of mTORC1 to the lysosome was suppressed by the dynamin inhibition. The activity and lysosomal recruitment of mTORC1 were rescued by increasing intracellular amino acids via cycloheximide exposure or by Rag overexpression, indicating that amino acid deprivation is the main cause of mTORC1 inactivation via the dynamin inhibition. We further show that endocytosis inhibition does not induce autophagy even though mTORC1 inactivation is known to strongly induce autophagy. These findings open new perspectives for the use of endocytosis inhibitors as potential agents that can effectively inhibit nutrient utilization and shut down the upstream signals that activate mTORC1. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Quantum spill-out in few-nanometer metal gaps: Effect on gap plasmons and reflectance from ultrasharp groove arrays

DEFF Research Database (Denmark)

Skjølstrup, Enok Johannes Haahr; Søndergaard, Thomas; Pedersen, Thomas Garm

2018-01-01

Plasmons in ultranarrow metal gaps are highly sensitive to the electron density profile at the metal surfaces. Using a quantum mechanical approach and assuming local response, we study the effects of electron spill-out on gap plasmons and reflectance from ultrasharp metal grooves.We demonstrate...... the reflectance from arrays of ultrasharp metal grooves. These findings are explained in terms of enhanced gap plasmon absorption taking place inside the gap 1–2 °A from the walls and delocalization near the groove bottom. Reflectance calculations taking spill-out into account are shown to be in much better...

[Research progress of larger flexion gap than extension gap in total knee arthroplasty].

Science.gov (United States)

Zhang, Weisong; Hao, Dingjun

2017-05-01

To summarize the progress of larger flexion gap than extension gap in total knee arthro-plasty (TKA). The domestic and foreign related literature about larger flexion gap than extension gap in TKA, and its impact factors, biomechanical and kinematic features, and clinical results were summarized. During TKA, to adjust the relations of flexion gap and extension gap is one of the key factors of successful operation. The biomechanical, kinematic, and clinical researches show that properly larger flexion gap than extension gap can improve both the postoperative knee range of motion and the satisfaction of patients, but does not affect the stability of the knee joint. However, there are also contrary findings. So adjustment of flexion gap and extension gap during TKA is still in dispute. Larger flexion gap than extension gap in TKA is a new joint space theory, and long-term clinical efficacy, operation skills, and related complications still need further study.

Precursor directed biosynthesis of odd-numbered fatty acids by different yeasts

Czech Academy of Sciences Publication Activity Database

Řezanka, Tomáš; Kolouchová, I.; Sigler, Karel

2015-01-01

Roč. 60, č. 5 (2015), s. 457-464 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GAP503/11/0215; GA ČR GA14-00227S Institutional support: RVO:61388971 Keywords : PSEUDOZYMA-FLOCCULOSA * HEPTADECENOIC ACID * METHYL-ESTERS Subject RIV: EE - Microbiology, Virology Impact factor: 1.335, year: 2015

Gap Junctions

Science.gov (United States)

Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

2013-01-01

Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

Bridging the Gap Between Theory and Practice

Directory of Open Access Journals (Sweden)

Roy H.M. Sembel

2015-05-01

Full Text Available Some concerns in the field of Business Management regarding the gap between theory and practice have been raised by practitioners and academicians. This keynote speech describes some lessons learned from the academic literature regarding this gap (whether the gap really exists, and if it exists, whether it needs to be bridged or closed, and how to bridge or close this gap, and shares the author's personal and professional experiences of living as both an academician and a practitioner. The main findings of this article are: (1 Yes the gap exists, however, it has to be viewed in a wider perspective to really understand the situation; (2 The gap in a specific area is bad and should become our concern, but in other areas it should not; (3 There are some ways to bridge or close the negative gap; (4 There exists hybrid career opportunities to become professionals that work both as an academician and a practitioner; (5 This new breed of hybrid professionals has a huge potential to bridge the bad theory-practice gap.

Amino Acids Regulate mTORC1 by an Obligate Two-step Mechanism*

Science.gov (United States)

Dyachok, Julia; Earnest, Svetlana; Iturraran, Erica N.; Cobb, Melanie H.

2016-01-01

The mechanistic target of rapamycin complex 1 (mTORC1) coordinates cell growth with its nutritional, hormonal, energy, and stress status. Amino acids are critical regulators of mTORC1 that permit other inputs to mTORC1 activity. However, the roles of individual amino acids and their interactions in mTORC1 activation are not well understood. Here we demonstrate that activation of mTORC1 by amino acids includes two discrete and separable steps: priming and activation. Sensitizing mTORC1 activation by priming amino acids is a prerequisite for subsequent stimulation of mTORC1 by activating amino acids. Priming is achieved by a group of amino acids that includes l-asparagine, l-glutamine, l-threonine, l-arginine, l-glycine, l-proline, l-serine, l-alanine, and l-glutamic acid. The group of activating amino acids is dominated by l-leucine but also includes l-methionine, l-isoleucine, and l-valine. l-Cysteine predominantly inhibits priming but not the activating step. Priming and activating steps differ in their requirements for amino acid concentration and duration of treatment. Priming and activating amino acids use mechanisms that are distinct both from each other and from growth factor signaling. Neither step requires intact tuberous sclerosis complex of proteins to activate mTORC1. Concerted action of priming and activating amino acids is required to localize mTORC1 to lysosomes and achieve its activation. PMID:27587390

Hemimorphite Flotation with 1-hydroxydodecylidene-1,1-diphosphonic acid and Its Mechanism

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Wen Tan

2018-01-01

Full Text Available 1-hydroxydodecylidene-1,1-diphosphonic acid (HDDPA was prepared and first applied in flotation of hemimorphite. HDDPA exhibited superior flotation performances for recovery of hemimorphite in comparison with lauric acid, and it also possessed good selectivity against quartz flotation under pH 7.0–11.0. Contact angle results revealed that HDDPA preferred to attach on hemimorphite rather than quartz and promoted the hydrophobicity of hemimorphite surfaces. In the presence of HDDPA anions, the zeta potential of hemimorphite particles shifted to more negative value even if hemimorphite was negatively charged, inferring a strong chemisorption of hemimorphite to HDDPA. The Fourier transform infrared (FTIR recommended that HDDPA might anchor on hemimorphite surfaces through bonding the oxygen atoms of its P(=O–O groups with surface Zn(II atoms. X-ray photoelectron spectroscopy (XPS gave additional evidence that the Zn(II-HDDPA surface complexes were formed on hemimorphite.

Analysis of serum anion gap and osmolal gap in diagnosis and prognosis of acute methanol poisoning: clinical study in 86 patients

Czech Academy of Sciences Publication Activity Database

Zakharov, S.; Navrátil, Tomáš; Pelclová, D.

2015-01-01

Roč. 146, č. 5 (2015), s. 787-794 ISSN 0026-9247 R&D Projects: GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388955 Keywords : serum anion gap * osmolal gap * acute methanol poisoning Subject RIV: CG - Electrochemistry Impact factor: 1.131, year: 2015

Cadmium Alters the Concentration of Fatty Acids in THP-1 Macrophages.

Science.gov (United States)

Olszowski, Tomasz; Gutowska, Izabela; Baranowska-Bosiacka, Irena; Łukomska, Agnieszka; Drozd, Arleta; Chlubek, Dariusz

2018-03-01

Fatty acid composition of human immune cells influences their function. The aim of this study was to evaluate the effects of known toxicant and immunomodulator, cadmium, at low concentrations on levels of selected fatty acids (FAs) in THP-1 macrophages. The differentiation of THP-1 monocytes into macrophages was achieved by administration of phorbol myristate acetate. Macrophages were incubated with various cadmium chloride (CdCl 2 ) solutions for 48 h at final concentrations of 5 nM, 20 nM, 200 nM, and 2 μM CdCl 2 . Fatty acids were extracted from samples according to the Folch method. The fatty acid levels were determined using gas chromatography. The following fatty acids were analyzed: long-chain saturated fatty acids (SFAs) palmitic acid and stearic acid, very long-chain saturated fatty acid (VLSFA) arachidic acid, monounsaturated fatty acids (MUFAs) palmitoleic acid, oleic acid and vaccenic acid, and n-6 polyunsaturated fatty acids (PUFAs) linoleic acid and arachidonic acid. Treatment of macrophages with very low concentrations of cadmium (5-200 nM) resulted in significant reduction in the levels of arachidic, palmitoleic, oleic, vaccenic, and linoleic acids and significant increase in arachidonic acid levels (following exposure to 5 nM Cd), without significant reduction of palmitic and stearic acid levels. Treatment of macrophages with the highest tested cadmium concentration (2 μM) produced significant reduction in the levels of all examined FAs: SFAs, VLSFA, MUFAs, and PUFAs. In conclusion, cadmium at tested concentrations caused significant alterations in THP-1 macrophage fatty acid levels, disrupting their composition, which might dysregulate fatty acid/lipid metabolism thus affecting macrophage behavior and inflammatory state.

Changes in drug utilization during a gap in insurance coverage: an examination of the medicare Part D coverage gap.

Directory of Open Access Journals (Sweden)

Jennifer M Polinski

2011-08-01

Full Text Available Nations are struggling to expand access to essential medications while curbing rising health and drug spending. While the US government's Medicare Part D drug insurance benefit expanded elderly citizens' access to drugs, it also includes a controversial period called the "coverage gap" during which beneficiaries are fully responsible for drug costs. We examined the impact of entering the coverage gap on drug discontinuation, switching to another drug for the same indication, and drug adherence. While increased discontinuation of and adherence to essential medications is a regrettable response, increased switching to less expensive but therapeutically interchangeable medications is a positive response to minimize costs.We followed 663,850 Medicare beneficiaries enrolled in Part D or retiree drug plans with prescription and health claims in 2006 and/or 2007 to determine who reached the gap spending threshold, n = 217,131 (33%. In multivariate Cox proportional hazards models, we compared drug discontinuation and switching rates in selected drug classes after reaching the threshold between all 1,993 who had no financial assistance during the coverage gap (exposed versus 9,965 multivariate propensity score-matched comparators with financial assistance (unexposed. Multivariate logistic regressions compared drug adherence (≤ 80% versus >80% of days covered. Beneficiaries reached the gap spending threshold on average 222 d ±79. At the drug level, exposed beneficiaries were twice as likely to discontinue (hazard ratio [HR]  = 2.00, 95% confidence interval [CI] 1.64-2.43 but less likely to switch a drug (HR  = 0.60, 0.46-0.78 after reaching the threshold. Gap-exposed beneficiaries were slightly more likely to have reduced adherence (OR  = 1.07, 0.98-1.18.A lack of financial assistance after reaching the gap spending threshold was associated with a doubling in discontinuing essential medications but not switching drugs in 2006 and 2007

Pannexin-1 channels show distinct morphology and no gap junction characteristics in mammalian cells.

Science.gov (United States)

Beckmann, Anja; Grissmer, Alexander; Krause, Elmar; Tschernig, Thomas; Meier, Carola

2016-03-01

Pannexins (Panx) are proteins with a similar membrane topology to connexins, the integral membrane protein of gap junctions. Panx1 channels are generally of major importance in a large number of system and cellular processes and their function has been thoroughly characterized. In contrast, little is known about channel structure and subcellular distribution. We therefore determine the subcellular localization of Panx1 channels in cultured cells and aim at the identification of channel morphology in vitro. Using freeze-fracture replica immunolabeling on EYFP-Panx1-overexpressing HEK 293 cells, large particles were identified in plasma membranes, which were immunogold-labeled using either GFP or Panx1 antibodies. There was no labeling or particles in the nuclear membranes of these cells, pointing to plasma membrane localization of Panx1-EYFP channels. The assembly of particles was irregular, this being in contrast to the regular pattern of gap junctions. The fact that no counterparts were identified on apposing cells, which would have been indicative of intercellular signaling, supported the idea of Panx1 channels within one membrane. Control cells (transfected with EYFP only, non-transfected) were devoid of both particles and immunogold labeling. Altogether, this study provides the first demonstration of Panx1 channel morphology and assembly in intact cells. The identification of Panx1 channels as large particles within the plasma membrane provides the knowledge required to enable recognition of Panx1 channels in tissues in future studies. Thus, these results open up new avenues for the detailed analysis of the subcellular localization of Panx1 and of its nearest neighbors such as purinergic receptors in vivo.

Copper(II) complex with 6-methylpyridine-2-carboxyclic acid: Experimental and computational study on the XRD, FT-IR and UV-Vis spectra, refractive index, band gap and NLO parameters.

Science.gov (United States)

Altürk, Sümeyye; Avcı, Davut; Başoğlu, Adil; Tamer, Ömer; Atalay, Yusuf; Dege, Necmi

2018-02-05

Crystal structure of the synthesized copper(II) complex with 6-methylpyridine-2-carboxylic acid, [Cu(6-Mepic) 2 ·H 2 O]·H 2 O, was determined by XRD, FT-IR and UV-Vis spectroscopic techniques. Furthermore, the geometry optimization, harmonic vibration frequencies for the Cu(II) complex were carried out by using Density Functional Theory calculations with HSEh1PBE/6-311G(d,p)/LanL2DZ level. Electronic absorption wavelengths were obtained by using TD-DFT/HSEh1PBE/6-311G(d,p)/LanL2DZ level with CPCM model and major contributions were determined via Swizard/Chemissian program. Additionally, the refractive index, linear optical (LO) and non-nonlinear optical (NLO) parameters of the Cu(II) complex were calculated at HSEh1PBE/6-311G(d,p) level. The experimental and computed small energy gap shows the charge transfer in the Cu(II) complex. Finally, the hyperconjugative interactions and intramolecular charge transfer (ICT) were studied by performing of natural bond orbital (NBO) analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Mythic gaps

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William Hansen

2014-11-01

Full Text Available Different kinds of omissions sometimes occur, or are perceived to occur, in traditional narratives and in tradition-inspired literature. A familiar instance is when a narrator realizes that he or she does not fully remember the story that he or she has begun to tell, and so leaves out part of it, which for listeners may possibly result in an unintelligible narrative. But many instances of narrative gap are not so obvious. From straightforward, objective gaps one can distinguish less-obvious subjective gaps: in many cases narrators do not leave out anything crucial or truly relevant from their exposition, and yet readers perceive gaps and take steps to fill them. The present paper considers four examples of subjective gaps drawn from ancient Greek literature (the Pandora myth, ancient Roman literature (the Pygmalion legend, ancient Hebrew literature (the Joseph legend, and early Christian literature (the Jesus legend. I consider the quite varied ways in which interpreters expand the inherited texts of these stories, such as by devising names, manufacturing motives, creating backstories, and in general filling in biographical ellipses. Finally, I suggest an explanation for the phenomenon of subjective gaps, arguing that, despite their variety, they have a single cause.

Perceptions and experiences of a gender gap at a Canadian research institute and potential strategies to mitigate this gap: a sequential mixed-methods study.

Science.gov (United States)

Mascarenhas, Alekhya; Moore, Julia E; Tricco, Andrea C; Hamid, Jemila; Daly, Caitlin; Bain, Julie; Jassemi, Sabrina; Kiran, Tara; Baxter, Nancy; Straus, Sharon E

2017-01-01

The gender gap in academia is long-standing. Failure to ensure that our academic faculty reflect our student pool and national population deprives Canada of talent. We explored the gender distribution and perceptions of the gender gap at a Canadian university-affiliated, hospital-based research institute. We completed a sequential mixed-methods study. In phase 1, we used the research institute's registry of scientists (1999-2014) and estimated overall prevalence of a gender gap and the gap with respect to job description (e.g., associate v. full-time) and research discipline. In phase 2, we conducted qualitative interviews to provide context for phase 1 data. Both purposive and snowball sampling were used for recruitment. The institute included 30.1% ( n = 62) women and 69.9% ( n = 144) men, indicating a 39.8% gender gap. Most full-time scientists (60.3%, n = 70) were clinicians; there were 54.2% more male than female clinician scientists. Ninety-five percent of basic scientists were men, indicating a 90.5% gap. Seven key themes emerged from 21 interviews, including perceived impact of the gender gap, factors perceived to influence the gap, recruitment trends, presence of institutional support, mentorship and suggestions to mitigate the gap. Several factors were postulated to contribute to the gender gap, including unconscious bias in hiring. A substantial gender gap exists within this research institute. Participants identified strategies to address this gap, such as establishing transparent search processes, providing opportunities for informal networking and mentorship of female scientists and establishing institutional support for work-life balance.

Band Gap Optimization Design of Photonic Crystals Material

Science.gov (United States)

Yu, Y.; Yu, B.; Gao, X.

2017-12-01

The photonic crystal has a fundamental characteristic - photonic band gap, which can prevent light to spread in the crystals. This paper studies the width variation of band gaps of two-dimension square lattice photonic crystals by changing the geometrical shape of the unit cells’ inner medium column. Using the finite element method, we conduct numerical experiments on MATLAB 2012a and COMSOL 3.5. By shortening the radius in vertical axis and rotating the medium column, we design a new unit cell, with a 0.3*3.85e-7 vertical radius and a 15 degree deviation to the horizontal axis. The new cell has a gap 1.51 percent wider than the circle medium structure in TE gap and creates a 0.0124 wide TM gap. Besides, the experiment shows the first TM gap is partially overlapped by the second TE gap in gap pictures. This is helpful to format the absolute photonic band gaps and provides favorable theoretical basis for designing photonic communication material.

THE PAL 5 STAR STREAM GAPS

International Nuclear Information System (INIS)

Carlberg, R. G.; Hetherington, Nathan; Grillmair, C. J.

2012-01-01

Pal 5 is a low-mass, low-velocity-dispersion, globular cluster with spectacular tidal tails. We use the Sloan Digital Sky Survey Data Release 8 data to extend the density measurements of the trailing star stream to 23 deg distance from the cluster, at which point the stream runs off the edge of the available sky coverage. The size and the number of gaps in the stream are measured using a filter which approximates the structure of the gaps found in stream simulations. We find 5 gaps that are at least 99% confidence detections with about a dozen gaps at 90% confidence. The statistical significance of a gap is estimated using bootstrap resampling of the control regions on either side of the stream. The density minimum closest to the cluster is likely the result of the epicyclic orbits of the tidal outflow and has been discounted. To create the number of 99% confidence gaps per unit length at the mean age of the stream requires a halo population of nearly a thousand dark matter sub-halos with peak circular velocities above 1 km s –1 within 30 kpc of the galactic center. These numbers are a factor of about three below cold stream simulation at this sub-halo mass or velocity but, given the uncertainties in both measurement and more realistic warm stream modeling, are in substantial agreement with the LCDM prediction.

Experimental study on the boiling phenomena within a narrow gap

International Nuclear Information System (INIS)

Aoki, S.; Inoue, A.; Aritomi, M.; Sakamoto, Y.

1982-01-01

Experiments were carried out with annular narrow gaps having the gap widths 0.2,0.3,0.4,0.5,1.0 and 1.5 mm for the following two cases: (a) for the ''open bottom'' case, the heat transfer coefficient was improved as the gap width decreases, but it was not affected by gap lengths in the range 40 <= L <= 100 mm. (b) for the ''closed bottom'' case, the heat transfer coefficient was not affected by gap width or length. The transition heat flux could be correlated by the equivalent gap length defined in terms of the cross-sectional area of the open end. (author)

Ultra-small (r1 year) copper oxide quantum dots with wide band gap

Science.gov (United States)

Talluri, Bhusankar; Prasad, Edamana; Thomas, Tiju

2018-01-01

Practical use of quantum dots (QDs) will rely on processes that enable (i) monodispersity, (ii) scalability, (iii) green approaches to manufacturing them. We demonstrate, a green, rapid, soft chemical, and industrial viable approach for obtaining quasi-spherical, ultra-small (size ∼2.4 ± 0.5 nm), stable (>1 yr), and monodispersed copper oxide QDs (r gap (Eg∼5.3 eV), this substantial band gap increase is currently inexplicable using Brus' equation, and is likely due to surface chemistry of these strongly confined QDs. Capping with triethanolamine (TEA) results in reduction in the average particle diameter from 9 ± 4 nm to 2.4 ± 0.5 nm and an increase of zeta potential (ξ) from +12 ± 2 mV to +31 ± 2 mV. XPS and electron diffraction studies indicate that capped copper oxide QDs which have TEA chemisorbed on its surface are expected to partly stabilize Cu (I) resulting in mixed phase in these QDs. This result is likely to inform efforts that involve achieving monodisperse microstructures and nano-structures, of oxides with a tendency for multivalency.

The Expanded Large Scale Gap Test

Science.gov (United States)

1987-03-01

NSWC TR 86-32 DTIC THE EXPANDED LARGE SCALE GAP TEST BY T. P. LIDDIARD D. PRICE RESEARCH AND TECHNOLOGY DEPARTMENT ’ ~MARCH 1987 Ap~proved for public...arises, to reduce the spread in the LSGT 50% gap value.) The worst charges, such as those with the highest or lowest densities, the largest re-pressed...Arlington, VA 22217 PE 62314N INS3A 1 RJ14E31 7R4TBK 11 TITLE (Include Security CIlmsilficatiorn The Expanded Large Scale Gap Test . 12. PEIRSONAL AUTHOR() T

A model for gap conductance in nuclear fuel rods

International Nuclear Information System (INIS)

Loyalka, S.K.

1982-01-01

Computation of nuclear reactor fuel behavior under normal and off-normal conditions is influenced by gap conductance models. These models should provide accurate results for heat transfer for arbitrary gap widths and gas mixtures and should be based on considerations of the kinetic theory of gases. There has been considerable progress in the study of heat transfer in a simple gas for arbitrary Knudsen numbers (Kn = l/similar to d, where l is a meanfree-path and similar d is the gap width) in recent years. Using these recent results, a simple expression for heat transfer in a gas mixture (enclosed between parallel plates) for an arbitrary Knudsen number has been constructed, and a new model for gap conductance has been proposed. The latter reproduces the free molecular (small gap, Kn >> 1) and the jump limits (large gaps, Kn << 1) correctly, and it provides fairly accurate results for arbitrary gap widths. The new model is suitable for use in large fuel behavior computer programs

Optical properties of (AlxGa1-x)(0.52)In0.48P at the crossover from a direct-gap to an indirect-gap semiconductor

DEFF Research Database (Denmark)

Dörr, U.; Schwarz, W.; Wörner, A.

1998-01-01

The optical properties and the dynamics of excitons and the electron-hole plasma have been studied in disordered (AlxGa1 – x)0.52In0.48P near to the direct-to-indirect band gap crossover. In particular we have investigated three epitaxial layers grown by solid-source molecular beam epitaxy...... recombination processes depends strongly on temperature, excitation intensity, and excitation pulse duration, the processes can be identified by changing these parameters. As a result, we can determine the relative alignment of the conduction band minima and the distribution of the electrons among them. At high...... with varying Al content x. Two of them have compositions in the immediate vicinity of the crossover point, the other is assigned to the indirect-gap regime. Both direct and indirect recombination processes contribute to the photon emission from the material. Since the relative importance of the different...

Further Studies on Oxalic Acid Biosynthesis in Oxalate-accumulating Plants 1

Science.gov (United States)

Nuss, Richard F.; Loewus, Frank A.

1978-01-01

l-Ascorbic acid functions as a precursor of oxalic acid in several oxalate-accumulating plants. The present study extends this observation to include Rumex crispus L. (curly dock), Amaranthus retroflexus L. (red root pigweed), Chenopodium album L. (lamb's-quarters), Beta vulgaris L. (sugar beet), Halogeton glomeratus M. Bieb. (halogeton), and Rheum rhabarbarum L. (rhubarb). Several species with low oxalate content are also examined. When l-[1-14C]ascorbic acid is supplied to young seedlings of R. crispus or H. glomeratus, a major portion of the 14C is released over a 24-hour period as 14CO2 and only a small portion is recovered as [14C]oxalate, unlike cuttings from 2- or 4-month-old plants which retain a large part of the 14C as [14C]oxalic acid and release very little 14CO2. Support for an intermediate role of oxalate in the release of 14CO2 from l-[1-14C]ascorbic acid is seen in the rapid release of 14CO2 by R. crispus and H. glomeratus seedlings labeled with [14C]oxalic acid. The common origin of oxalic acid carbon in the C1 and C2 fragment from l-ascorbic acid is demonstrated by comparison of 14C content of oxalic acid in several oxalate-accumulators after cuttings or seedlings are supplied equal amounts of l-[1-14C]- or l-[UL-14C]ascorbic acid. Theoretically, l-[1-14C]ascorbic acid will produce labeled oxalic acid containing three times as much 14C as l-[UL-14C]ascorbic acid when equal amounts of label are provided. Experimentally, a ratio of 2.7 ± 0.5 is obtained in duplicate experiments with six different species. PMID:16660342

The influence of gap to the mass flux

International Nuclear Information System (INIS)

Kim, S. K.; Kang, C. H.; Hwang, Y. S.

2000-01-01

It was known that the release of gap is very important for I-129, Cs, which have high solubility. According to the disposal concept of spent fuel, there is a little gap between fuel rods and a canister. There is a concept that this gap may be filled with sand or beads, but it is impossible to perfectly fill for this gap, so the gap is one of important parameter in release mechanism. In this paper, the influence of gap was carried out. Gap volume have a little influence in the early stage(within a year), but there is not to significantly affect after 1 year. We have to consider the influence of filling material in canister such as cast iron, which have not considered on this paper

(Dimethylphosphorylmethanaminium hydrogen oxalate–oxalic acid (2/1

Directory of Open Access Journals (Sweden)

Sebastian Bialek

2014-03-01

Full Text Available The reaction of (dimethylphosphorylmethanamine (dpma with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4−·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-molecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16° whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°. In the crystal, the components are connected by strong O—H...O and much weaker N—H...O hydrogen bonds, leading to the formation of layers extending parallel to (001. The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio.

Hard diffraction and rapidity gaps

International Nuclear Information System (INIS)

Brandt, A.

1995-09-01

The field of hard diffraction, which studies events with a rapidity gap and a hard scattering, has expanded dramatically recently. A review of new results from CDF, D OE, H1 and ZEUS will be given. These results include diffractive jet production, deep-inelastic scattering in large rapidity gap events, rapidity gaps between high transverse energy jets, and a search for diffractive W-boson production. The combination of these results gives new insight into the exchanged object, believed to be the pomeron. The results axe consistent with factorization and with a hard pomeron that contains both quarks and gluons. There is also evidence for the exchange of a strongly interacting color singlet in high momentum transfer (36 2 ) events

Synthesis of new low band gap dyes with BF{sub 2}-azopyrrole complex and their use for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Mikroyannidis, John A. [Chemical Technology Laboratory, Department of Chemistry, University of Patras, GR-26500 Patras (Greece); Roy, M.S. [Defence Laboratory, Jodhpur (Raj.) (India); Sharma, G.D. [Physics Department, Molecular Electronic and Optoelectronic Device Laboratory, JNV University, Jodhpur (Raj.) 342005 (India); Jaipur Engineering College, Kukas, Jaipur (Raj.) (India)

2010-08-15

The diazonium salt derived from 4-aminobenzoic acid, 4-aminophenol or 2-aminophenol reacted with half equivalent of pyrrole to afford symmetrical 2,5-bisazopyrroles. They reacted subsequently with boron trifluoride in the presence of triethylamine to afford the corresponding BF{sub 2}-azopyrrole complexes D1, D2 and D3 respectively. They were soluble and stable in nonprotic solvents such as chloroform, dichloromethane and tetrahydrofuran but unstable in protic solvents such as ethanol. Their absorption spectra were broad with optical band gap of 1.49-1.70 eV. Among these dyes D2 displayed the broader absorption spectrum with low band gap E{sub g}{sup opt} of 1.49 eV. We have utilized these complexes as photosensitizers for quasi solid state dye-sensitized solar cells (DSSCs) and achieved power conversion efficiency in the range of 4.0-6.0%. We have also found that the co-adsorption of citric acid hindered the formation of dye aggregates and might improve the electron injection efficiency leading to an enhancement in short circuit photocurrent. This work suggests that metal-free dyes based on BF{sub 2}-azopyrrole complex are promising candidates for improvement of the DSSC performance. (author)

Amino acid properties conserved in molecular evolution.

Directory of Open Access Journals (Sweden)

Witold R Rudnicki

Full Text Available That amino acid properties are responsible for the way protein molecules evolve is natural and is also reasonably well supported both by the structure of the genetic code and, to a large extent, by the experimental measures of the amino acid similarity. Nevertheless, there remains a significant gap between observed similarity matrices and their reconstructions from amino acid properties. Therefore, we introduce a simple theoretical model of amino acid similarity matrices, which allows splitting the matrix into two parts - one that depends only on mutabilities of amino acids and another that depends on pairwise similarities between them. Then the new synthetic amino acid properties are derived from the pairwise similarities and used to reconstruct similarity matrices covering a wide range of information entropies. Our model allows us to explain up to 94% of the variability in the BLOSUM family of the amino acids similarity matrices in terms of amino acid properties. The new properties derived from amino acid similarity matrices correlate highly with properties known to be important for molecular evolution such as hydrophobicity, size, shape and charge of amino acids. This result closes the gap in our understanding of the influence of amino acids on evolution at the molecular level. The methods were applied to the single family of similarity matrices used often in general sequence homology searches, but it is general and can be used also for more specific matrices. The new synthetic properties can be used in analyzes of protein sequences in various biological applications.

The Knowledge Gap Versus the Belief Gap and Abstinence-Only Sex Education.

Science.gov (United States)

Hindman, Douglas Blanks; Yan, Changmin

2015-08-01

The knowledge gap hypothesis predicts widening disparities in knowledge of heavily publicized public affairs issues among socioeconomic status groups. The belief gap hypothesis extends the knowledge gap hypothesis to account for knowledge and beliefs about politically contested issues based on empirically verifiable information. This analysis of 3 national surveys shows belief gaps developed between liberals and conservatives regarding abstinence-only sex education; socioeconomic status-based knowledge gaps did not widen. The findings partially support both belief gap and knowledge gap hypotheses. In addition, the unique contributions of exposure to Fox News, CNN, and MSNBC in this process were investigated. Only exposure to Fox News was linked to beliefs about abstinence-only sex education directly and indirectly through the cultivation of conservative ideology.

Gap Width Study and Fixture Design in Laser Butt-Welding

DEFF Research Database (Denmark)

Gong, Hui; Olsen, Flemming Ove

.5-2.0 m/min, the laser power : 2 and 2.6 kW and the focal point position : 0 and -1.2 mm. Quality of all the butt welds are destructively tested according to ISO 13919-1.Influences of the variable process parameters to the maximum allowable gap width are observed as (1) the maximum gap width is inversely......This paper discusses some practical consideration for design of a mechanical fixture, which enables to accurately measure the width of a gap between two stainless steel workpieces and to steadfastly clamp the workpieces for butt-welding with a high power CO2 laser.With such a fixture, a series...... of butt-welding experiment is successfully carried out in order to find the maximum allowable gap width in laser butt-welding. The gap width study (GWS) is performed on the material of SST of W1.4401 (AISI 316) under various welding conditions, which are the gap width : 0.00-0.50 mm, the welding speed : 0...

Metabolic Acidosis or Respiratory Alkalosis? Evaluation of a Low Plasma Bicarbonate Using the Urine Anion Gap.

Science.gov (United States)

Batlle, Daniel; Chin-Theodorou, Jamie; Tucker, Bryan M

2017-09-01

Hypobicarbonatemia, or a reduced bicarbonate concentration in plasma, is a finding seen in 3 acid-base disorders: metabolic acidosis, chronic respiratory alkalosis and mixed metabolic acidosis and chronic respiratory alkalosis. Hypobicarbonatemia due to chronic respiratory alkalosis is often misdiagnosed as a metabolic acidosis and mistreated with the administration of alkali therapy. Proper diagnosis of the cause of hypobicarbonatemia requires integration of the laboratory values, arterial blood gas, and clinical history. The information derived from the urinary response to the prevailing acid-base disorder is useful to arrive at the correct diagnosis. We discuss the use of urine anion gap, as a surrogate marker of urine ammonium excretion, in the evaluation of a patient with low plasma bicarbonate concentration to differentiate between metabolic acidosis and chronic respiratory alkalosis. The interpretation and limitations of urine acid-base indexes at bedside (urine pH, urine bicarbonate, and urine anion gap) to evaluate urine acidification are discussed. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Phylogenetic and bioinformatic analysis of gap junction-related proteins, innexins, pannexins and connexins.

Science.gov (United States)

Fushiki, Daisuke; Hamada, Yasuo; Yoshimura, Ryoichi; Endo, Yasuhisa

2010-04-01

All multi-cellular animals, including hydra, insects and vertebrates, develop gap junctions, which communicate directly with neighboring cells. Gap junctions consist of protein families called connexins in vertebrates and innexins in invertebrates. Connexins and innexins have no homology in their amino acid sequence, but both are thought to have some similar characteristics, such as a tetra-membrane-spanning structure, formation of a channel by hexamer, and transmission of small molecules (e.g. ions) to neighboring cells. Pannexins were recently identified as a homolog of innexins in vertebrate genomes. Although pannexins are thought to share the function of intercellular communication with connexins and innexins, there is little information about the relationship among these three protein families of gap junctions. We phylgenetically and bioinformatically examined these protein families and other tetra-membrane-spanning proteins using a database and three analytical softwares. The clades formed by pannexin families do not belong to the species classification but do to paralogs of each member of pannexins. Amino acid sequences of pannexins are closely related to those of innexins but less to those of connexins. These data suggest that innexins and pannexins have a common origin, but the relationship between innexins/pannexins and connexins is as slight as that of other tetra-membrane-spanning members.

Regression analysis for bivariate gap time with missing first gap time data.

Science.gov (United States)

Huang, Chia-Hui; Chen, Yi-Hau

2017-01-01

We consider ordered bivariate gap time while data on the first gap time are unobservable. This study is motivated by the HIV infection and AIDS study, where the initial HIV contracting time is unavailable, but the diagnosis times for HIV and AIDS are available. We are interested in studying the risk factors for the gap time between initial HIV contraction and HIV diagnosis, and gap time between HIV and AIDS diagnoses. Besides, the association between the two gap times is also of interest. Accordingly, in the data analysis we are faced with two-fold complexity, namely data on the first gap time is completely missing, and the second gap time is subject to induced informative censoring due to dependence between the two gap times. We propose a modeling framework for regression analysis of bivariate gap time under the complexity of the data. The estimating equations for the covariate effects on, as well as the association between, the two gap times are derived through maximum likelihood and suitable counting processes. Large sample properties of the resulting estimators are developed by martingale theory. Simulations are performed to examine the performance of the proposed analysis procedure. An application of data from the HIV and AIDS study mentioned above is reported for illustration.

Characterization of BASP1-mediated neurite outgrowth

DEFF Research Database (Denmark)

Korshunova, Irina; Caroni, Pico; Kolkova, Kateryna

2008-01-01

The brain acid-soluble protein BASP1 (CAP-23, NAP-22) belongs to the family of growth-associated proteins, which also includes GAP-43, a protein recently shown to regulate neural cell adhesion molecule (NCAM)-mediated neurite outgrowth. Here, the effects of BASP1 overexpression were investigated...

Acidic tumor microenvironment abrogates the efficacy of mTORC1 inhibitors.

Science.gov (United States)

Faes, Seraina; Duval, Adrian P; Planche, Anne; Uldry, Emilie; Santoro, Tania; Pythoud, Catherine; Stehle, Jean-Christophe; Horlbeck, Janine; Letovanec, Igor; Riggi, Nicolo; Demartines, Nicolas; Dormond, Olivier

2016-12-05

Blocking the mechanistic target of rapamycin complex-1 (mTORC1) with chemical inhibitors such as rapamycin has shown limited clinical efficacy in cancer. The tumor microenvironment is characterized by an acidic pH which interferes with cancer therapies. The consequences of acidity on the anti-cancer efficacy of mTORC1 inhibitors have not been characterized and are thus the focus of our study. Cancer cell lines were treated with rapamycin in acidic or physiological conditions and cell proliferation was investigated. The effect of acidity on mTORC1 activity was determined by Western blot. The anticancer efficacy of rapamycin in combination with sodium bicarbonate to increase the intratumoral pH was tested in two different mouse models and compared to rapamycin treatment alone. Histological analysis was performed on tumor samples to evaluate proliferation, apoptosis and necrosis. Exposing cancer cells to acidic pH in vitro significantly reduced the anti-proliferative effect of rapamycin. At the molecular level, acidity significantly decreased mTORC1 activity, suggesting that cancer cell proliferation is independent of mTORC1 in acidic conditions. In contrast, the activation of mitogen-activated protein kinase (MAPK) or AKT were not affected by acidity, and blocking MAPK or AKT with a chemical inhibitor maintained an anti-proliferative effect at low pH. In tumor mouse models, the use of sodium bicarbonate increased mTORC1 activity in cancer cells and potentiated the anti-cancer efficacy of rapamycin. Combining sodium bicarbonate with rapamycin resulted in increased tumor necrosis, increased cancer cell apoptosis and decreased cancer cell proliferation as compared to single treatment. Taken together, these results emphasize the inefficacy of mTORC1 inhibitors in acidic conditions. They further highlight the potential of combining sodium bicarbonate with mTORC1 inhibitors to improve their anti-tumoral efficacy.

Whole-Genome Sequence Analysis of Bombella intestini LMG 28161T, a Novel Acetic Acid Bacterium Isolated from the Crop of a Red-Tailed Bumble Bee, Bombus lapidarius.

Directory of Open Access Journals (Sweden)

Leilei Li

Full Text Available The whole-genome sequence of Bombella intestini LMG 28161T, an endosymbiotic acetic acid bacterium (AAB occurring in bumble bees, was determined to investigate the molecular mechanisms underlying its metabolic capabilities. The draft genome sequence of B. intestini LMG 28161T was 2.02 Mb. Metabolic carbohydrate pathways were in agreement with the metabolite analyses of fermentation experiments and revealed its oxidative capacity towards sucrose, D-glucose, D-fructose and D-mannitol, but not ethanol and glycerol. The results of the fermentation experiments also demonstrated that the lack of effective aeration in small-scale carbohydrate consumption experiments may be responsible for the lack of reproducibility of such results in taxonomic studies of AAB. Finally, compared to the genome sequences of its nearest phylogenetic neighbor and of three other insect associated AAB strains, the B. intestini LMG 28161T genome lost 69 orthologs and included 89 unique genes. Although many of the latter were hypothetical they also included several type IV secretion system proteins, amino acid transporter/permeases and membrane proteins which might play a role in the interaction with the bumble bee host.

VOLTAMMETRY OF AQUEOUS CHLOROAURIC ACID WITH HANGING MERCURY DROP ELECTRODE

Czech Academy of Sciences Publication Activity Database

Korshunov, A.; Josypčuk, Bohdan; Heyrovský, Michael

2011-01-01

Roč. 76, č. 7 (2011), s. 929-936 ISSN 0010-0765 R&D Projects: GA ČR GAP206/11/1638; GA AV ČR IAA400400806; GA MŠk(CZ) LC06063 Institutional research plan: CEZ:AV0Z40400503 Keywords : aqueous chloauric acid * voltammetry * hanging mercury drop electrode Subject RIV: CG - Electrochemistry Impact factor: 1.283, year: 2011

Ursolic acid inhibits adipogenesis in 3T3-L1 adipocytes through LKB1/AMPK pathway.

Directory of Open Access Journals (Sweden)

Yonghan He

Full Text Available BACKGROUND: Ursolic acid (UA is a triterpenoid compound with multiple biological functions. This compound has recently been reported to possess an anti-obesity effect; however, the mechanisms are less understood. OBJECTIVE: As adipogenesis plays a critical role in obesity, the present study was conducted to investigate the effect of UA on adipogenesis and mechanisms of action in 3T3-L1 preadipocytes. METHODS AND RESULTS: The 3T3-L1 preadipocytes were induced to differentiate in the presence or absence of UA for 6 days. The cells were determined for proliferation, differentiation, fat accumulation as well as the protein expressions of molecular targets that regulate or are involved in fatty acid synthesis and oxidation. The results demonstrated that ursolic acid at concentrations ranging from 2.5 µM to 10 µM dose-dependently attenuated adipogenesis, accompanied by reduced protein expression of CCAAT element binding protein β (C/EBPβ, peroxisome proliferator-activated receptor γ (PPARγ, CCAAT element binding protein α (C/EBPα and sterol regulatory element binding protein 1c (SREBP-1c, respectively. Ursolic acid increased the phosphorylation of acetyl-CoA carboxylase (ACC and protein expression of carnitine palmitoyltransferase 1 (CPT1, but decreased protein expression of fatty acid synthase (FAS and fatty acid-binding protein 4 (FABP4. Ursolic acid increased the phosphorylation of AMP-activated protein kinase (AMPK and protein expression of (silent mating type information regulation 2, homolog 1 (Sirt1. Further studies demonstrated that the anti-adipogenic effect of UA was reversed by the AMPK siRNA, but not by the Sirt1 inhibitor nicotinamide. Liver kinase B1 (LKB1, the upstream kinase of AMPK, was upregulated by UA. When LKB1 was silenced with siRNA or the inhibitor radicicol, the effect of UA on AMPK activation was diminished. CONCLUSIONS: Ursolic acid inhibited 3T3-L1 preadipocyte differentiation and adipogenesis through the LKB1/AMPK

Bridging the Gap (BRIEFING CHARTS)

Science.gov (United States)

2007-03-05

1 Defense Advanced Research Projects Agency “Bridging the Gap ” Dr. Robert F. Leheny Deputy Director Report Documentation Page Form ApprovedOMB No...comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to...4. TITLE AND SUBTITLE Bridging the Gap 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

Gap formation in Danish beech (Fagus sylvatica) forests of low management intensity

DEFF Research Database (Denmark)

Ritter, Eva; Vesterdal, Lars

2006-01-01

-based managed forest, soil solution was collected for 5 years and soil moisture measured in the fourth year after gap formation. Average NO3-N concentrations were significantly higher in the gaps (9.9 and 8.1 mg NO3-N l(-1), respectively) than under closed canopy (0.2 mg l(-1)). In the semi-natural forest......, measurements were carried out up to 29 months after gap formation. Average NO3-N concentrations in the gap were 19.3 mg NO3-N l(-1). Gap formation alone did not account for this high level, as concentrations were high also under closed canopy (average 12.4 mg NO3-N l(-1)). However, the gap had significantly...... higher N concentrations when trees were in full leaf, and NO3-N drainage losses were significantly increased in the gap. No losses occurred under closed canopy in growing seasons. Soil moisture was close to field capacity in all three gaps, but decreased under closed canopy in growing seasons...

Chicoric acid: chemistry, distribution, and production

Science.gov (United States)

Lee, Jungmin; Scagel, Carolyn

2013-12-01

Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 63 genera and species have been found to contain chicoric acid, and while the compound is used as a processing quality indicator, it may also have useful health benefits. This review of chicoric acid summarizes research findings and highlights gaps in research knowledge for investigators, industry stakeholders, and consumers alike. Additionally, chicoric acid identification and quantification methods, biosynthesis, processing improvements to increase chicoric acid retention, and potential areas for future research are discussed.

Closing the Gender Gap: Act Now

Science.gov (United States)

OECD Publishing (NJ3), 2012

2012-01-01

Gender gaps are pervasive in all walks of economic life and imply large losses in terms of foregone productivity and living standards to the individuals concerned and the economy. This new OECD report focuses on how best to close these gender gaps under four broad headings: (1) Gender equality, social norms and public policies; and gender equality…

Magnetic microparticles post-synthetically coated by hyaluronic acid as an enhanced carrier for microfluidic bioanalysis

Czech Academy of Sciences Publication Activity Database

Holubová, L.; Knotek, P.; Palarčik, J.; Čadková, M.; Bělina, P.; Vlček, Milan; Korecká, L.; Bílková, Z.

2014-01-01

Roč. 44, 1 November (2014), s. 345-351 ISSN 0928-4931 R&D Projects: GA ČR GAP206/12/0381 Institutional support: RVO:61389013 Keywords : coating * hyaluronic acid * hyaluronan Subject RIV: CA - Inorganic Chemistry Impact factor: 3.088, year: 2014

Evidence for Consistency of the Glycation Gap in Diabetes

OpenAIRE

Nayak, Ananth U.; Holland, Martin R.; Macdonald, David R.; Nevill, Alan; Singh, Baldev M.

2011-01-01

OBJECTIVE Discordance between HbA1c and fructosamine estimations in the assessment of glycemia is often encountered. A number of mechanisms might explain such discordance, but whether it is consistent is uncertain. This study aims to coanalyze paired glycosylated hemoglobin (HbA1c)-fructosamine estimations by using fructosamine to determine a predicted HbA1c, to calculate a glycation gap (G-gap) and to determine whether the G-gap is consistent over time. RESEARCH DESIGN AND METHODS We include...

Role of NPR1 dependent and NPR1 independent genes in response to Salicylic acid

Directory of Open Access Journals (Sweden)

Neha Agarwal

2017-10-01

Full Text Available NPR1 (Nonexpressor of pathogenesis-related gene is a transcription coactivator and central regulator of systemic acquired resistance (SAR pathway. It controls wide range of pathogenesis related genes involved in various defense responses, acts by sensing SAR signal molecule, Salicylic acid (SA. Mutation in NPR1 results in increased susceptibility to pathogen infection and less expression of pathogenesis related genes. The present study aimed to identify the role of NPR1 in gene expression after the Salicylic acid induction. For this RNA-seq was performed in Arabidopsis thaliana Col-0 and npr1-1 in response to Salicylic acid. RNA-seq analysis revealed a total of 3811 differentially expressed gene in which 2109 genes are up-regulated and 1702 genes are down-regulated. We have divided these genes in 6 categories SA induced (SI, SA repressed (SR, NPR1 dependent SI (ND-SI, NPR1 dependent SR (ND-SR, NPR1 independent SI (NI-SI, NPR1 independent SR (NI-SR. Further, Gene ontology and MapMan pathway analysis of differentially expressed genes suggested variety of biological processes and metabolic pathways that are enriched during SAR defense pathway. These results contribute to shed light on importance of both NPR1-dependent (ND and NPR1-independent (NI gene acting downstream to Salicylic acid induction in SAR pathway. The present study aimed to identify the role of NPR1 in gene expression after the Salicylic acid induction.

Probing the Electronic Structure and Band Gap Evolution of Titanium Oxide Clusters (TiO2)n- (n=1-10) Using Photoelectron Spectroscopy

International Nuclear Information System (INIS)

Zhai, Hua-jin; Wang, Lai S.

2007-01-01

TiO2 is a wide-band gap semiconductor and it is an important material for photocatalysis. Here we report an experimental investigation of the electronic structure of (TiO2)n clusters and how their band gap evolves as a function of size using anion photoelectron spectroscopy (PES). PES spectra of (TiO2)n- clusters for n = 1-10 have been obtained at 193 (6.424 eV) and 157 nm (7.866 eV). The high photon energy at 157 nm allows the band gap of the TiO2 clusters to be clearly revealed up to n = 10. The band gap is observed to be strongly size-dependent for n 1 appears to be localized in a tricoordinated Ti atom, creating a single Ti3+ site and making these clusters ideal molecular models for mechanistic understanding of TiO2 surface defects and photocatalytic properties

What is the Mass of a Gap-opening Planet?

Energy Technology Data Exchange (ETDEWEB)

Dong, Ruobing [Steward Observatory, University of Arizona, Tucson, AZ (United States); Fung, Jeffrey, E-mail: rdong@email.arizona.edu [Department of Astronomy, University of California, Berkeley, CA (United States)

2017-02-01

High-contrast imaging instruments such as GPI and SPHERE are discovering gap structures in protoplanetary disks at an ever faster pace. Some of these gaps may be opened by planets forming in the disks. In order to constrain planet formation models using disk observations, it is crucial to find a robust way to quantitatively back out the properties of the gap-opening planets, in particular their masses, from the observed gap properties, such as their depths and widths. Combining 2D and 3D hydrodynamics simulations with 3D radiative transfer simulations, we investigate the morphology of planet-opened gaps in near-infrared scattered-light images. Quantitatively, we obtain correlations that directly link intrinsic gap depths and widths in the gas surface density to observed depths and widths in images of disks at modest inclinations under finite angular resolution. Subsequently, the properties of the surface density gaps enable us to derive the disk scale height at the location of the gap h , and to constrain the quantity M {sub p}{sup 2}/ α , where M {sub p} is the mass of the gap-opening planet and α characterizes the viscosity in the gap. As examples, we examine the gaps recently imaged by VLT/SPHERE, Gemini/GPI, and Subaru/HiCIAO in HD 97048, TW Hya, HD 169142, LkCa 15, and RX J1615.3-3255. Scale heights of the disks and possible masses of the gap-opening planets are derived assuming each gap is opened by a single planet. Assuming α = 10{sup −3}, the derived planet masses in all cases are roughly between 0.1 and 1 M {sub J}.

Soil moisture in sessile oak forest gaps

Science.gov (United States)

Zagyvainé Kiss, Katalin Anita; Vastag, Viktor; Gribovszki, Zoltán; Kalicz, Péter

2015-04-01

By social demands are being promoted the aspects of the natural forest management. In forestry the concept of continuous forest has been an accepted principle also in Hungary since the last decades. The first step from even-aged stand to continuous forest can be the forest regeneration based on gap cutting, so small openings are formed in a forest due to forestry interventions. This new stand structure modifies the hydrological conditions for the regrowth. Without canopy and due to the decreasing amounts of forest litter the interception is less significant so higher amount of precipitation reaching the soil. This research focuses on soil moisture patterns caused by gaps. The spatio-temporal variability of soil water content is measured in gaps and in surrounding sessile oak (Quercus petraea) forest stand. Soil moisture was determined with manual soil moisture meter which use Time-Domain Reflectometry (TDR) technology. The three different sizes gaps (G1: 10m, G2: 20m, G3: 30m) was opened next to Sopron on the Dalos Hill in Hungary. First, it was determined that there is difference in soil moisture between forest stand and gaps. Second, it was defined that how the gap size influences the soil moisture content. To explore the short term variability of soil moisture, two 24-hour (in growing season) and a 48-hour (in dormant season) field campaign were also performed in case of the medium-sized G2 gap along two/four transects. Subdaily changes of soil moisture were performed. The measured soil moisture pattern was compared with the radiation pattern. It was found that the non-illuminated areas were wetter and in the dormant season the subdaily changes cease. According to our measurements, in the gap there is more available water than under the forest stand due to the less evaporation and interception loss. Acknowledgements: The research was supported by TÁMOP-4.2.2.A-11/1/KONV-2012-0004 and AGRARKLIMA.2 VKSZ_12-1-2013-0034.

Selective Enrichment of Omega-3 Fatty Acids in Oils by Phospholipase A1.

Directory of Open Access Journals (Sweden)

Tushar Ranjan Moharana

Full Text Available Omega fatty acids are recognized as key nutrients for healthier ageing. Lipases are used to release ω-3 fatty acids from oils for preparing enriched ω-3 fatty acid supplements. However, use of lipases in enrichment of ω-3 fatty acids is limited due to their insufficient specificity for ω-3 fatty acids. In this study use of phospholipase A1 (PLA1, which possesses both sn-1 specific activity on phospholipids and lipase activity, was explored for hydrolysis of ω-3 fatty acids from anchovy oil. Substrate specificity of PLA1 from Thermomyces lenuginosus was initially tested with synthetic p-nitrophenyl esters along with a lipase from Bacillus subtilis (BSL, as a lipase control. Gas chromatographic characterization of the hydrolysate obtained upon treatment of anchovy oil with these enzymes indicated a selective retention of ω-3 fatty acids in the triglyceride fraction by PLA1 and not by BSL. 13C NMR spectroscopy based position analysis of fatty acids in enzyme treated and untreated samples indicated that PLA1 preferably retained ω-3 fatty acids in oil, while saturated fatty acids were hydrolysed irrespective of their position. Hydrolysis of structured triglyceride,1,3-dioleoyl-2-palmitoylglycerol, suggested that both the enzymes hydrolyse the fatty acids at both the positions. The observed discrimination against ω-3 fatty acids by PLA1 appears to be due to its fatty acid selectivity rather than positional specificity. These studies suggest that PLA1 could be used as a potential enzyme for selective concentrationof ω-3 fatty acids.

Selective Enrichment of Omega-3 Fatty Acids in Oils by Phospholipase A1.

Science.gov (United States)

Ranjan Moharana, Tushar; Byreddy, Avinesh R; Puri, Munish; Barrow, Colin; Rao, Nalam Madhusudhana

2016-01-01

Omega fatty acids are recognized as key nutrients for healthier ageing. Lipases are used to release ω-3 fatty acids from oils for preparing enriched ω-3 fatty acid supplements. However, use of lipases in enrichment of ω-3 fatty acids is limited due to their insufficient specificity for ω-3 fatty acids. In this study use of phospholipase A1 (PLA1), which possesses both sn-1 specific activity on phospholipids and lipase activity, was explored for hydrolysis of ω-3 fatty acids from anchovy oil. Substrate specificity of PLA1 from Thermomyces lenuginosus was initially tested with synthetic p-nitrophenyl esters along with a lipase from Bacillus subtilis (BSL), as a lipase control. Gas chromatographic characterization of the hydrolysate obtained upon treatment of anchovy oil with these enzymes indicated a selective retention of ω-3 fatty acids in the triglyceride fraction by PLA1 and not by BSL. 13C NMR spectroscopy based position analysis of fatty acids in enzyme treated and untreated samples indicated that PLA1 preferably retained ω-3 fatty acids in oil, while saturated fatty acids were hydrolysed irrespective of their position. Hydrolysis of structured triglyceride,1,3-dioleoyl-2-palmitoylglycerol, suggested that both the enzymes hydrolyse the fatty acids at both the positions. The observed discrimination against ω-3 fatty acids by PLA1 appears to be due to its fatty acid selectivity rather than positional specificity. These studies suggest that PLA1 could be used as a potential enzyme for selective concentrationof ω-3 fatty acids.

2-[(1-Benzamido-2-methoxy-2-oxoethylamino]benzoic Acid

Directory of Open Access Journals (Sweden)

Alami Anouar

2013-01-01

Full Text Available The carboxylic α,α-diaminoester 2-[(1-benzamido-2-methoxy-2-oxoethyl amino]benzoic acid is obtained by N-alkylation of methyl α-azido glycinate N-benzoylated with 2-aminobenzoic acid.

40 CFR 721.4575 - L-aspartic acid, N,N′- [(1E) - 1,2 - ethenediylbis[(3-sulfo-4, 1-phenylene)imino [6-(phenylamino...

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false L-aspartic acid, N,Nâ²- [(1E) - 1,2... Substances § 721.4575 L-aspartic acid, N,N′- [(1E) - 1,2 - ethenediylbis[(3-sulfo-4, 1-phenylene)imino [6... uses subject to reporting. (1) The chemical substance identified as l-aspartic acid, N,N′- [(1E) - 1,2...

Housing Instability and Children's Health Insurance Gaps.

Science.gov (United States)

Carroll, Anne; Corman, Hope; Curtis, Marah A; Noonan, Kelly; Reichman, Nancy E

To assess the extent to which housing instability is associated with gaps in health insurance coverage of preschool-age children. Secondary analysis of data from the Early Childhood Longitudinal Study-Birth Cohort, a nationally representative study of children born in the United States in 2001, was conducted to investigate associations between unstable housing-homelessness, multiple moves, or living with others and not paying rent-and children's subsequent health insurance gaps. Logistic regression was used to adjust for potentially confounding factors. Ten percent of children were unstably housed at age 2, and 11% had a gap in health insurance between ages 2 and 4. Unstably housed children were more likely to have gaps in insurance compared to stably housed children (16% vs 10%). Controlling for potentially confounding factors, the odds of a child insurance gap were significantly higher in unstably housed families than in stably housed families (adjusted odds ratio 1.27; 95% confidence interval 1.01-1.61). The association was similar in alternative model specifications. In a US nationally representative birth cohort, children who were unstably housed at age 2 were at higher risk, compared to their stably housed counterparts, of experiencing health insurance gaps between ages 2 and 4 years. The findings from this study suggest that policy efforts to delink health insurance renewal processes from mailing addresses, and potentially routine screenings for housing instability as well as referrals to appropriate resources by pediatricians, would help unstably housed children maintain health insurance. Copyright © 2017 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Band gap bowing in quaternary nitride semiconducting alloys

DEFF Research Database (Denmark)

Gorczyka, Isabela; Suski, T.; Christensen, Niels Egede

2011-01-01

Structural properties of InxGayAl1−x−yN alloys are derived from total-energy minimization within the local-density approximation (LDA). The electronic properties are studied by band structure calculations including a semiempirical correction for the “LDA gap error.” The effects of varying...... the composition and atomic arrangements are examined using a supercell geometry. An analytical expression for the band gap is derived for the entire range of compositions. The range of (x, y) values for which InxGayAl1−x−yN is lattice matched to GaN, and the ensuing energy gaps, are given. This range of available...... gaps becomes smaller when In atoms form clusters. Comparison to experimental data is made....

GAP Analysis Program (GAP)

Data.gov (United States)

Kansas Data Access and Support Center — The Kansas GAP Analysis Land Cover database depicts 43 land cover classes for the state of Kansas. The database was generated using a two-stage hybrid classification...

1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds

Czech Academy of Sciences Publication Activity Database

Hermann, K.; Meinhard, J.; Dobrev, Petre; Linkies, A.; Pešek, Bedřich; Heß, B.; Macháčková, Ivana; Fischer, U.; Leubner-Metzger, G.

2007-01-01

Roč. 58, č. 11 (2007), s. 3047-3060 ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid (ABA) * ABA 8'-hydroxylase (CYP707A) * 1-aminocyclopropane-1-carboxylic acid ( ACC ) Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

Anti-inflammatory effects of polyunsaturated fatty acids in THP-1 cells

International Nuclear Information System (INIS)

Zhao Guixiang; Etherton, Terry D.; Martin, Keith R.; Vanden Heuvel, John P.; Gillies, Peter J.; West, Sheila G.; Kris-Etherton, Penny M.

2005-01-01

The effects of linoleic acid (LA), α-linolenic acid (ALA), and docosahexaenoic acid (DHA) were compared to that of palmitic acid (PA), on inflammatory responses in human monocytic THP-1 cells. When cells were pre-incubated with fatty acids for 2-h and then stimulated with lipopolysaccharide for 24-h in the presence of fatty acids, secretion of interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNFα) was significantly decreased after treatment with LA, ALA, and DHA versus PA (P 12,14 -prostaglandin J2 (15d-PGJ2) and were dose-dependent. In addition, LA, ALA, and DHA decreased IL-6, IL-1β, and TNFα gene expression (P < 0.05 for all) and nuclear factor (NF)-κB DNA-binding activity, whereas peroxisome proliferator-activated receptor-γ (PPARγ) DNA-binding activity was increased. The results indicate that the anti-inflammatory effects of polyunsaturated fatty acids may be, in part, due to the inhibition of NF-κB activation via activation of PPARγ

Gap Junctions Contribute to Ictal/Interictal Genesis in Human Hypothalamic Hamartomas

Directory of Open Access Journals (Sweden)

Jie Wu

2016-06-01

Full Text Available Human hypothalamic hamartoma (HH is a rare subcortical lesion associated with treatment-resistant epilepsy. Cellular mechanisms responsible for epileptogenesis are unknown. We hypothesized that neuronal gap junctions contribute to epileptogenesis through synchronous activity within the neuron networks in HH tissue. We studied surgically resected HH tissue with Western-blot analysis, immunohistochemistry, electron microscopy, biocytin microinjection of recorded HH neurons, and microelectrode patch clamp recordings with and without pharmacological blockade of gap junctions. Normal human hypothalamus tissue was used as a control. Western blots showed increased expression of both connexin-36 (Cx36 and connexin-43 (Cx43 in HH tissue compared with normal human mammillary body tissue. Immunohistochemistry demonstrated that Cx36 and Cx43 are expressed in HH tissue, but Cx36 was mainly expressed within neuron clusters while Cx43 was mainly expressed outside of neuron clusters. Gap-junction profiles were observed between small HH neurons with electron microscopy. Biocytin injection into single recorded small HH neurons showed labeling of adjacent neurons, which was not observed in the presence of a neuronal gap-junction blocker, mefloquine. Microelectrode field recordings from freshly resected HH slices demonstrated spontaneous ictal/interictal-like discharges in most slices. Bath-application of gap-junction blockers significantly reduced ictal/interictal-like discharges in a concentration-dependent manner, while not affecting the action-potential firing of small gamma-aminobutyric acid (GABA neurons observed with whole-cell patch-clamp recordings from the same patient's HH tissue. These results suggest that neuronal gap junctions between small GABAergic HH neurons participate in the genesis of epileptic-like discharges. Blockade of gap junctions may be a new therapeutic strategy for controlling seizure activity in HH patients.

The urban perspectives of acid rain

International Nuclear Information System (INIS)

Tonn, B.E.

1993-01-01

This report documents discussions held during a workshop an Urban Perspective of Acid Rain. The workshop was sponsored by the Office of the Director, National Acid Precipitation Assessment Program (NAPAP). NAPAP anticipates giving increased emphasis to the benefits in urban areas of emissions reductions. The goal of this informal, exploratory workshop was to serve as a first step towards identifying pollutant monitoring, and research and assessment needs to help answer, from an urban perspective, the two key questions posed to NAPAP by Congress: (1) what are the costs, benefits, and effectiveness of the acid rain control program, and (2) what reductions in deposition, rates are needed in order to prevent adverse effects? The workshop addressed research activities needed to respond to these questions. The discussions focused. sequentially, on data needs, data and model availability, and data and modeling gaps. The discussions concentrated on four areas of effects: human health, materials, urban forests, and visibility

Reactivity of cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids with diazodiphenylmethane in aprotic solvents

Directory of Open Access Journals (Sweden)

VERA V. KRSTIC

2000-12-01

Full Text Available Rate constants for the reaction of diazodiphenylmethane with cyclohex-1-enylcarboxylic acid and 2-methylcyclohex-1-enylcarboxylic acid were determined in nine aprotic solvents, as well as in seven protic solvents, at 30°C using the appropriate UV-spectroscopic method. In protic solvents the unsubsituted acid displayed higher reaction rates than the methyl-substituted one. The results in aprotic solvents showed quite the opposite, and the reaction rates were considerably lower. In order to explain the obtained results through solvent effects, reaction rate constants (k of the examined acids were correlated using the total solvatochromic equation of the form: log k=logk0+sp*+aa+bb, where p* is the measure of the solvent polarity, a represents the scale of the solvent hydrogen bond donor acidities (HBD and b represents the scale of the solvent hydrogen bond acceptor basicities (HBA. The correlation of the kinetic data were carried out by means of multiple linear regression analysis and the opposite effects of aprotic solvents, as well as the difference in the influence of protic and aprotic solvents on the reaction of the two examined acids with DDM were discussed. The results presented in this paper for cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids were compared with the kinetic data for benzoic acid obtained in the same chemical reaction, under the same experimental conditions.

Cloning, sequencing and variability analysis of the gap gene from Mycoplasma hominis

DEFF Research Database (Denmark)

Mygind, Tina; Jacobsen, Iben Søgaard; Melkova, Renata

2000-01-01

The gap gene encodes the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The gene was cloned and sequenced from the Mycoplasma hominis type strain PG21(T). The intraspecies variability was investigated by inspection of restriction fragment length polymorphism (RFLP) patterns...... after polymerase chain reaction (PCR) amplification of the gap gene from 15 strains and furthermore by sequencing of part of the gene in eight strains. The M. hominis gap gene was found to vary more than the Escherichia coli counterpart, but the variation at nucleotide level gave rise to only a few...... amino acid substitutions. To verify that the gene was expressed in M. hominis, a polyclonal antibody was produced and tested against whole cell protein from 15 strains. The enzyme was expressed in all strains investigated as a 36-kDa protein. All strains except type strain PG21(T) showed reaction...

MV controlled spark gap

International Nuclear Information System (INIS)

Evdokimovich, V.M.; Evlampiev, S.B.; Korshunov, G.S.; Nikolaev, V.A.; Sviridov, Yu.F.; Khmyrov, V.V.

1980-01-01

A megavolt gas-filled trigatron gap with a sectional gas-discharge chamber having a more than three-fold range of operating voltages is described. The discharge chamber consists of ten sections, each 70 mm thick, made of organic glass. The sections are separated one from another by aluminium gradient rings to which ohmic voltage divider is connected. Insulational sections and gradient rings are braced between themselves by means of metal flanges through gaskets made of oil-resistant rubber with the help of fiberglass-laminate pins. The gap has two electrodes 110 mm in diameter. The trigatron ignition assembly uses a dielectric bushing projecting over the main electrode plane. Use has been made of a gas mixture containing 10% of SF 6 and 90% of air making possible to ensure stable gap operation without readjusting in the voltage range from 0.4 to 1.35 MV. The operation time lag in this range is equal to 10 μs at a spread of [ru

The Arabidopsis thaliana REDUCED EPIDERMAL FLUORESCENCE1 gene encodes an aldehyde dehydrogenase involved in ferulic acid and sinapic acid biosynthesis.

Science.gov (United States)

Nair, Ramesh B; Bastress, Kristen L; Ruegger, Max O; Denault, Jeff W; Chapple, Clint

2004-02-01

Recent research has significantly advanced our understanding of the phenylpropanoid pathway but has left in doubt the pathway by which sinapic acid is synthesized in plants. The reduced epidermal fluorescence1 (ref1) mutant of Arabidopsis thaliana accumulates only 10 to 30% of the sinapate esters found in wild-type plants. Positional cloning of the REF1 gene revealed that it encodes an aldehyde dehydrogenase, a member of a large class of NADP(+)-dependent enzymes that catalyze the oxidation of aldehydes to their corresponding carboxylic acids. Consistent with this finding, extracts of ref1 leaves exhibit low sinapaldehyde dehydrogenase activity. These data indicate that REF1 encodes a sinapaldehyde dehydrogenase required for sinapic acid and sinapate ester biosynthesis. When expressed in Escherichia coli, REF1 was found to exhibit both sinapaldehyde and coniferaldehyde dehydrogenase activity, and further phenotypic analysis of ref1 mutant plants showed that they contain less cell wall-esterified ferulic acid. These findings suggest that both ferulic acid and sinapic acid are derived, at least in part, through oxidation of coniferaldehyde and sinapaldehyde. This route is directly opposite to the traditional representation of phenylpropanoid metabolism in which hydroxycinnamic acids are instead precursors of their corresponding aldehydes.

Effects of coverage gap reform on adherence to diabetes medications.

Science.gov (United States)

Zeng, Feng; Patel, Bimal V; Brunetti, Louis

2013-04-01

To investigate the impact of Part D coverage gap reform on diabetes medication adherence. Retrospective data analysis based on pharmacy claims data from a national pharmacy benefit manager. We used a difference-in-difference-indifference method to evaluate the impact of coverage gap reform on adherence to diabetes medications. Two cohorts (2010 and 2011) were constructed to represent the last year before Affordable Care Act (ACA) reform and the first year after reform, respectively. Each patient had 2 observations: 1 before and 1 after entering the coverage gap. Patients in each cohort were divided into groups based on type of gap coverage: no coverage, partial coverage (generics only), and full coverage. Following ACA reform, patients with no gap coverage and patients with partial gap coverage experienced substantial drops in copayments in the coverage gap in 2011. Their adherence to diabetes medications in the gap, measured by percentage of days covered, improved correspondingly (2.99 percentage points, 95% confidence interval [CI] 0.49-5.48, P = .019 for patients with no coverage; 6.46 percentage points, 95% CI 3.34-9.58, P gap in 2011. However, their adherence did not increase (-0.13 percentage point, P = .8011). In the first year of ACA coverage gap reform, copayments in the gap decreased substantially for all patients. Patients with no coverage and patients with partial coverage in the gap had better adherence in the gap in 2011.

Bridging the Gap

DEFF Research Database (Denmark)

Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska

Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

Interaction of the Bragg gap with polaritonic gap in opal photonic crystals

Science.gov (United States)

Nayer, Eradat; Sivachenko, Andrey Yu; Li, Sergey; Raikh, Mikhail E.; Valy Vardeny, Z.

2001-03-01

Photonic crystals (PC) are a class of artificial structures with a periodic dielectric function. PCs can be a laboratory for testing fundamental processes involving interactions of radiation with matter in novel conditions. We have studied the optical properties of opal PCs that are infiltrated with highly polarizable media such as j-aggregates of cyanine dyes. Opals are self- assembled structures of silica (SiO_2) spheres. We report our studies on clarifying the relationship between a polaritonic gap and a photonic stop band (Bragg gap) when they resonantly coexist in the same structure. Infiltration of opal with polarizable molecules combines the polaritonic and Bragg diffractive effects. Both effects exist independently when the Bragg (at ω=ω_B) and polaritonic (at ω=ω_T) resonances are well separated in frequency. A completely different situation occurs when ωT =ω_B. Such a condition was achieved in opals that were infiltrated with J-aggregates of cyanine dyes that have large Rabi frequency. Our measurements show some dramatic changes in the shape of the reflectivity plateaus, which are due to the interplay between the photonic band gap and the polaritonic gap. The experimental results on reflectivity and its dependence on the light propagation angle and concentration of the cyanie dyes are in agreement with the theoretical calculations. (The work was supported in part by Army Research office DAAD19-00-1-0406.)

Guidelines for Adolescent Preventive Services: the GAPS in practice.

Science.gov (United States)

Gadomski, Anne; Bennett, Shannon; Young, Margaret; Wissow, Lawrence S

2003-05-01

Pre- and post-Guidelines for Adolescent Preventive Services (GAPS) comparison of outcomes gathered via chart audit. A rural hospital-based general pediatric clinic. Adolescents who underwent annual examinations between April 1, 1998, and March 31, 2001. A random sample of 441 medical records was reviewed. Training in the GAPS model and use of the questionnaire began in April 1998. Detection of, discussion of, and referrals for GAPS-related risk behavior. The medical records of 162 younger adolescents (aged 11-15 years) and 279 older adolescents (aged 16-19 years) were audited. Detection of risk behaviors increased from 19% at baseline to 95% with the initial GAPS and 87% with the periodic GAPS. The most prevalent risk factor was having a rifle or gun in the home (younger adolescents, 47% and older adolescents, 39%). The mean number of risk behaviors and health concerns documented was higher in the initial GAPS (4.8 and 1.3, respectively) than in the periodic GAPS (3.8 and 0.7) (P =.01 and.006). The GAPS questionnaires detected lower levels of risk behavior compared with a local Youth Risk Behavior Survey. Controlling for sex, age, and clinician, discussion of psychosocial topics increased during the study period; however, there was considerable variation among clinicians regarding the topics addressed. The GAPS-related referral rate did not change significantly. The GAPS model increases clinicians' detection and discussion of risk behaviors.

Pressure and gap length dependence of gap breakdown voltage and discharge current of discharge-pumped KrF excimer laser. Hoden reiki KrF laser no zetsuen hakai den prime atsu to reiki denryu no atsuryoku, gap cho izon sei

Energy Technology Data Exchange (ETDEWEB)

Yukimura, K.; Kawakami, H. (Doshisha Univ., Tokyo (Japan)); Hitomi, K. (Kyoto Polytechnic College, Kyoto (Japan))

1991-04-20

On the gap destruction characteristics of UV-preionized discharge-pumped KrF excimer laser (charge transfer type) and the electric characteristics of the excited discharge, studies were made by changing the pressure (1.5-3 atm) and the discharge gap length (14-21 mm) of the discharge medium. (1) Gap breakdown voltage and the maximum current of the excited discharge give a similarity by a product of pressure and the gap length at the charge volatge. (2) Insulation breakdown of the gap occurs at the wave front of the applied voltage and the breakdown time gets delayed by the decreasing voltage applied. By setting the ionization index at constant value 20, the gap breakdown voltage is estimated at the error within 10%. (3) The relation between the maximum current, pressure and the gap length product changes the characteristics by the charge voltage of the primary condenser. With the result combined with the standardization of voltage/current of the excited discharge, the electric characteristics at the specific pressure and gap length can be readily known. 10 refs., 10 figs.

Technique for estimating relocated gap width for gap conductance calculations

International Nuclear Information System (INIS)

Klink, P.H.

1978-01-01

Thermally induced fuel fragmentation and relocation has been demonstrated to influence the thermal behavior of a fuel rod in two ways. The effective fuel pellet conductivity is decreased and pellet-to-cladding heat transfer is improved. This paper presents a correlation between as-built and relocated gap width which, used with the Ross and Stoute Gap Conductance Correlation and an appropriate fuel thermal expansion model, closely predicts the measured gap conductances

High pressure gas-filled cermet spark gaps

International Nuclear Information System (INIS)

Avilov, Eh.A.; Yur'ev, A.L.

2000-01-01

The results of modernization of the R-48 and R-49 spark gaps making it possible to improve their electrical characteristics are presented. The design is described and characteristics of gas-filled cermet spark gaps are presented. By the voltage rise time of 5-6 μs in the Marx generator scheme they provide for the pulse break-through voltage of 120 and 150 kV. By the voltage rise time of 0.5-1 μs the break-through voltage of these spark gaps may be increased up to 130 and 220 kV. The proper commutation time is equal to ≤ 0.5 ns. Practical recommendations relative to designing cermet spark gaps are given [ru

Anatase nanoparticles surface modified with fused ring salicylate-type ligands (1-hydroxy-2-naphthoic acids): A combined DFT and experimental study

Energy Technology Data Exchange (ETDEWEB)

Savić, Tatjana D.; Čomor, Mirjana I.; Abazović, Nadica D.; Šaponjić, Zoran V.; Marinović-Cincović, Milena T. [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Veljković, Dušan Ž.; Zarić, Snežana D. [Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11058 Belgrade (Serbia); Janković, Ivana A., E-mail: ivanaj@vinca.rs [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia)

2015-05-05

Highlights: • Formation of the charge-transfer complexes results in a red shift of the TiO{sub 2} absorption. • Extended aromatic ring systems reduce the effective bang gap. • For the CT complexes formed stability constants in the order 10{sup 3} M{sup −1} were determined. • Binding was found to be through bidentate binuclear-bridging complexes. • Ligands interact with different active sites on the TiO{sub 2} surface that express energetic heterogeneity. - Abstract: Sensitization of TiO{sub 2} crystals and nanoparticles with appropriately chosen organic molecules can lead to a significant shift of their absorption threshold from the UV to the visible, thus improving the absorption of the solar spectrum as well as the efficiency of photocatalytic and photovoltaic devices. Herein, the surface modification of nanocrystalline TiO{sub 2} particles (45 Å) with salicylate-type ligands consisting of an extended aromatic ring system, specifically 1-hydroxy-2-naphthoic acid and 1,4-dihydroxy-2-naphthoic acid, was found to alter the optical properties of nanoparticles in a similar way to salicylic acid. From both absorption measurements and steady-state quenching measurements of modifier fluorescence upon binding to TiO{sub 2} in methanol/water = 90/10 solutions, stability constants in the order of 10{sup 3} M{sup −1} have been determined at pH 2. Fluorescence lifetime measurements, in the presence and absence of colloidal TiO{sub 2} nanoparticles, indicated that the fluorescence quenching process is primarily static quenching, thus proving the formation of a nonfluorescent charge-transfer (CT) complex. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TPD analysis (TG/DTA/MS). Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared

Chicoric acid: chemistry, distribution, and production

Directory of Open Access Journals (Sweden)

Jungmin eLee

2013-12-01

Full Text Available Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 63 genera and species have been found to contain chicoric acid, and while the compound is used as a processing quality indicator, it may also have useful health benefits. This review of chicoric acid summarizes research findings and highlights gaps in research knowledge for investigators, industry stakeholders, and consumers alike. Additionally, chicoric acid identification and quantification methods, biosynthesis, processing improvements to increase chicoric acid retention, and potential areas for future research are discussed.

1,5-Anhydro-D-fructose: regioselective acylation with fatty acids

DEFF Research Database (Denmark)

Lundt, Inge; Andersen, Søren Møller; Marcussen, Jan

1999-01-01

Regioselective acylation of 1,5-anhydro-D-fructose was performed with dodecanoic acid to give 1,5-anhydro-6-O-dodecanoyl-D-fructose, chemically in 50% yield and enzymatically in quantitative yield. Quantitative conversions were also obtained using hexadecanoic and octadecanoic acids as acyl donors...

Purine Restriction Induces Pronounced Translational Upregulation of the NT1 Adenosine/Pyrimidine Nucleoside Transporter in Leishmania major

OpenAIRE

Ortiz, Diana; Valdés, Raquel; Sanchez, Marco A.; Hayenga, Johanna; Elya, Carolyn; Detke, Siegfried; Landfear, Scott M.

2010-01-01

Leishmania and other parasitic protozoa are unable to synthesize purines de novo and are reliant upon purine nucleoside and nucleobase transporters to import preformed purines from their hosts. To study the roles of the four purine permeases NT1-NT4 in Leishmania major, null mutants in each transporter gene were prepared and the effect of each gene deletion on purine uptake was monitored. Deletion of the NT3 purine nucleobase transporter gene or both NT3 and the NT2 nucleoside transporter gen...

Bioproduction of L-Aspartic Acid and Cinnamic Acid by L-Aspartate Ammonia Lyase from Pseudomonas aeruginosa PAO1.

Science.gov (United States)

Patel, Arti T; Akhani, Rekha C; Patel, Manisha J; Dedania, Samir R; Patel, Darshan H

2017-06-01

Aspartase (L-aspartate ammonia lyase, EC 4.3.1.1) catalyses the reversible amination and deamination of L-aspartic acid to fumaric acid which can be used to produce important biochemical. In this study, we have explored the characteristics of aspartase from Pseudomonas aeruginosa PAO1 (PA-AspA). To overproduce PA-AspA, the 1425-bp gene was introduced in Escherichia coli BL21 and purified. A 51.0-kDa protein was observed as a homogenous purified protein on SDS-PAGE. The enzyme was optimally active at pH 8.0 and 35 °C. PA-AspA has retained 56% activity after 7 days of incubation at 35 °C, which displays the hyperthermostablility characteristics of the enzyme. PA-AspA is activated in the presence of metal ions and Mg2+ is found to be most effective. Among the substrates tested for specificity of PA-AspA, L-phenylalanine (38.35 ± 2.68) showed the highest specific activity followed by L-aspartic acid (31.21 ± 3.31) and fumarate (5.42 ± 2.94). K m values for L-phenylalanine, L-aspartic acid and fumarate were 1.71 mM, 0.346 μM and 2 M, respectively. The catalytic efficiency (k cat /K m ) for L-aspartic acid (14.18 s -1  mM -1 ) was higher than that for L-phenylalanine (4.65 s -1  mM -1 ). For bioconversion, from an initial concentration of 1000 mM of fumarate and 30 mM of L-phenylalanine, PA-AspA was found to convert 395.31 μM L-aspartic acid and 3.47 mM cinnamic acid, respectively.

Key mediators of intracellular amino acids signaling to mTORC1 activation.

Science.gov (United States)

Duan, Yehui; Li, Fengna; Tan, Kunrong; Liu, Hongnan; Li, Yinghui; Liu, Yingying; Kong, Xiangfeng; Tang, Yulong; Wu, Guoyao; Yin, Yulong

2015-05-01

Mammalian target of rapamycin complex 1 (mTORC1) is activated by amino acids to promote cell growth via protein synthesis. Specifically, Ras-related guanosine triphosphatases (Rag GTPases) are activated by amino acids, and then translocate mTORC1 to the surface of late endosomes and lysosomes. Ras homolog enriched in brain (Rheb) resides on this surface and directly activates mTORC1. Apart from the presence of intracellular amino acids, Rag GTPases and Rheb, other mediators involved in intracellular amino acid signaling to mTORC1 activation include human vacuolar sorting protein-34 (hVps34) and mitogen-activating protein kinase kinase kinase kinase-3 (MAP4K3). Those molecular links between mTORC1 and its mediators form a complicate signaling network that controls cellular growth, proliferation, and metabolism. Moreover, it is speculated that amino acid signaling to mTORC1 may start from the lysosomal lumen. In this review, we discussed the function of these mediators in mTORC1 pathway and how these mediators are regulated by amino acids in details.