Genomic Analysis Reveals Contrasting PIFq Contribution to Diurnal Rhythmic Gene Expression in PIF-Induced and -Repressed Genes.

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Martin, Guiomar; Soy, Judit; Monte, Elena

2016-01-01

Members of the PIF quartet (PIFq; PIF1, PIF3, PIF4, and PIF5) collectively contribute to induce growth in Arabidopsis seedlings under short day (SD) conditions, specifically promoting elongation at dawn. Their action involves the direct regulation of growth-related and hormone-associated genes. However, a comprehensive definition of the PIFq-regulated transcriptome under SD is still lacking. We have recently shown that SD and free-running (LL) conditions correspond to "growth" and "no growth" conditions, respectively, correlating with greater abundance of PIF protein in SD. Here, we present a genomic analysis whereby we first define SD-regulated genes at dawn compared to LL in the wild type, followed by identification of those SD-regulated genes whose expression depends on the presence of PIFq. By using this sequential strategy, we have identified 349 PIF/SD-regulated genes, approximately 55% induced and 42% repressed by both SD and PIFq. Comparison with available databases indicates that PIF/SD-induced and PIF/SD-repressed sets are differently phased at dawn and mid-morning, respectively. In addition, we found that whereas rhythmicity of the PIF/SD-induced gene set is lost in LL, most PIF/SD-repressed genes keep their rhythmicity in LL, suggesting differential regulation of both gene sets by the circadian clock. Moreover, we also uncovered distinct overrepresented functions in the induced and repressed gene sets, in accord with previous studies in other examined PIF-regulated processes. Interestingly, promoter analyses showed that, whereas PIF/SD-induced genes are enriched in direct PIF targets, PIF/SD-repressed genes are mostly indirectly regulated by the PIFs and might be more enriched in ABA-regulated genes.

Mechanism for the selective conjugation of ubiquitin to phytochrome

Energy Technology Data Exchange (ETDEWEB)

Vierstra, R.D.

1990-01-01

The goal of this project is to understand at the molecular level how phytochrome functions and how intracellular proteins are degraded. Phytochrome is marked for degradation by covalent attachment of ubiquitin. Ubiquitin-phytochrome conjugates (UbP) were characterized with respect to formation kinetics, subcellular localization and site of ubiquitin attachment. UbP appears to be a general phenomenon during phytochrome degradation in a variety of species. UbP was isolated from oat seedlings and characterized. Residues 747-830 of phytochrome have been identified as a possible attachment site for ubiquitin. By placing the gene for etiolated phytochrome in tobacco we have created a transgenic system for over expressing phytochrome. The effects of this over expression are described, and it appears that tobacco degrades this foreign protein through formation of UbP. We have created a series of site-directed mutants of the oat phytochrome gene, and are in the process of characterizing them to determine sequence requirements for ubiquination. 8 refs., 1 fig. (MHB)

Phytochromes in photosynthetically competent plants

Energy Technology Data Exchange (ETDEWEB)

Pratt, L.H.

1990-07-01

Plants utilize light as a source of information in photomorphogenesis and of free energy in photosynthesis, two processes that are interrelated in that the former serves to increase the efficiency with which plants can perform the latter. Only one pigment involved in photomorphogenesis has been identified unequivocally, namely phytochrome. The thrust of this proposal is to investigate this pigment and its mode(s) of action in photosynthetically competent plants. Our long term objective is to characterize phytochrome and its functions in photosynthetically competent plants from molecular, biochemical and cellular perspectives. It is anticipated that others will continue to contribute indirectly to these efforts at the physiological level. The ultimate goal will be to develop this information from a comparative perspective in order to learn whether the different phytochromes have significantly different physicochemical properties, whether they fulfill independent functions and if so what these different functions are, and how each of the different phytochromes acts at primary molecular and cellular levels.

Preimplantation Factor (PIF Promotes HLA-G, -E, -F, -C Expression in JEG-3 Choriocarcinoma Cells and Endogenous Progesterone Activity

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Miya Soukaina Hakam

2017-10-01

Full Text Available Background/Aims: Pregnancy success requires mandatory maternal tolerance of the semi/ allogeneic embryo involving embryo-derived signals. Expression levels of PreImplantation Factor (PIF, a novel peptide secreted by viable embryos, correlate with embryo development, and its early detection in circulation correlates with a favourable pregnancy outcome. PIF enhances endometrial receptivity to promote embryo implantation. Via the p53 pathway, it increases trophoblast invasion, improving cell survival / immune privilege. PIF also reduces spontaneous and LPS-induced foetal death in immune naïve murine model. We examined PIF effect on gene expression of human leukocyte antigen (HLA-G, -E -F and –C and the influence of PIF on local progesterone activity in JEG-3 choriocarcinoma cells. Methods: PIF and progesterone (P4 effects on JEG-3 cells surface and intracellular HLA molecules was tested using monoclonal antibodies, flow cytometry, and Western blotting. PIF and IL17 effects on P4 and cytokines secretion was determined by ELISA. PIF and P4 effects on JEG-3 cells proteome was examined using 2D gel staining followed by spot analysis, mass spectrometry and bioinformatic analysis. Results: In cytotrophoblastic JEG-3 cells PIF increased intracellular expression of HLA-G, HLA-F, HLA-E and HLA-C and surface expression of HLA-G, HLA-E and HLA-C in dose and time dependent manner. In case of HLA-E, -F results were confirmed also by Western blot. Proteome analysis confirmed an increase in HLA-G, pro-tolerance FOXP3+ regulatory T cells (Tregs, coagulation factors and complement regulator. In contrast, PIF reduced PRDX2 and HSP70s to negate oxidative stress and protein misfolding. PIF enhanced local progesterone activity, increasing steroid secretion and the receptor protein. It also promoted the secretion of the Th1/Th2 cytokines (IL-10, IL-1β, IL-8, GM-CSF and TGF-β1, resulting in improved maternal signalling. Conclusion: PIF can generate a pro

Interactions of phytochromes A, B1 and B2 in light-induced competence for adventitious shoot formation in hypocotyl of tomato (Solanum lycopersicum L.).

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Lercari, B; Bertram, L

2004-02-01

The interactions of phytochrome A (phyA), phytochrome B1 (phyB1) and phytochrome B2 (phyB2) in light-dependent shoot regeneration from the hypocotyl of tomato was analysed using all eight possible homozygous allelic combinations of the null mutants. The donor plants were pre-grown either in the dark or under red or far-red light for 8 days after sowing; thereafter hypocotyl segments (apical, middle and basal portions) were transferred onto hormone-free medium for culture under different light qualities. Etiolated apical segments cultured in vitro under white light showed a very high frequency of regeneration for all of the genotypes tested besides phyB1phyB2, phyAphyB1 and phyAphyB1phyB2 mutants. Evidence is provided of a specific interference of phyB2 with phyA-mediated HIR to far-red and blue light in etiolated explants. Pre-treatment of donor plants by growth under red light enhanced the competence of phyB1phyB2, phyAphyB1 and phyAphyB1phyB2 mutants for shoot regeneration, whereas pre-irradiation with far-red light enhanced the frequency of regeneration only in the phyAphyB1 mutant. Multiple phytochromes are involved in red light- and far-red light-dependent acquisition of competence for shoot regeneration. The position of the segments along the hypocotyl influenced the role of the various phytochromes and the interactions between them. The culture of competent hypocotyl segments under red, far-red or blue light reduced the frequency of explants forming shoots compared to those cultured under white light, with different genotypes having different response patterns.

Conformational heterogeneity of the Pfr chromophore in plant and cyanobacterial phytochromes

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Francisco eVelazquez Escobar

2015-07-01

Full Text Available Phytochromes are biological photoreceptors that can be reversibly photoconverted between a dark and photoactivated state. The underlying reaction sequences are initiated by the photoisomerisation of the tetrapyrrole cofactor, which in plant and cyanobacterial phytochromes are a phytochromobilin (PB and a phycocyanobilin (PCB, respectively. The transition between the two states represents an on/off-switch of the output module activating or deactivating downstream physiological processes. In addition, the photoactivated state, i.e. Pfr in canonical phytochromes, can be thermally reverted to the dark state (Pr. The present study aimed to improve our understanding of the specific reactivity of various PB- and PCB-binding phytochromes in the Pfr state by analyzing the cofactor structure by vibrational spectroscopic techniques. Resonance Raman (RR spectroscopy revealed two Pfr conformers (Pfr-I and Pfr-II forming a temperature-dependent conformational equilibrium. The two sub-states - found in all phytochromes studied, albeit with different relative contributions - differ in structural details of the C-D and A-B methine bridges. In the Pfr-I sub-state the torsion between the rings C and D is larger by ca. 10o compared to Pfr-II. This structural difference is presumably related to different hydrogen bonding interactions of ring D as revealed by time-resolved IR spectroscopic studies of the cyanobacterial phytochrome Cph1. The transitions between the two sub-states are evidently too fast (i.e., nanosecond time scale to be resolved by NMR spectroscopy which could not detect a structural heterogeneity of the chromophore in Pfr. The implications of the present findings for the dark reversion of the Pfr state are discussed.

Phytochrome A, phytochrome B and HY4 are involved in hypocotyl growth responses to natural radiation in Arabidopsis: weak de-etiolation of the phyA mutant under dense canopies

International Nuclear Information System (INIS)

Yanovsky, M.J.; Casal, J.J.; Whitelam, G.C.

1995-01-01

The roles of phytochrome A (phyA), phytochrome B (phyB) and a putative blue-light (BL) photoreceptor (HY4) in the control of hypocotyl growth by natural radiation were investigated using phyA, phyB and hy4 mutants of Arabidopsis thaliana. Full sunlight inhibited hypocotyl growth to a larger extent in wild-type (WT) than in phyA, phyB and, particularly, hy4 seedlings. In WT seedlings, hypocotyl growth was promoted by selectively lowering BL irradiance, lowering red-light (R) plus far-red-light (FR) irradiance or lowering the R/FR ratio (which was achieved either by increasing FR or by reducing R). The effects of lowering BL were reduced in hy4 and exaggerated in phyA seedlings. The effects of lowering R+FR were reduced in phyA and exaggerated in hy4 seedlings. Neither phyB nor hy4 mutants responded to low R/FR ratios. Neighbouring plants reflecting FR without shading caused subtle reductions of the R/FR ratio. This signal promoted hypocotyl growth in WT but not in phyA, phyB or hy4 seedlings. Intermediate canopy shade produced similar effects in all genotypes. Under deep shade, de-etiolation was severely impaired in phyA seedlings, which died prematurely. Thus, the FR ‘high-irradiance reaction’ mediated by phyA could be important for seedling survival under dense canopies. (author)

Evolution and functional analysis of the Pif97 gene of the Pacific oyster Crassostrea gigas

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Xiaotong WANG, Xiaorui SONG, Tong WANG, Qihui ZHU, Guoying MIAO, Yuanxin CHEN, Xiaodong FANG, Huayong QUE, Li LI, Guofan ZHANG

2013-02-01

Full Text Available Mollusc shell matrix proteins (SMPs are important functional components embedded in the shell and play a role in shell formation. A SMP (Pif177 was identified previously from the nacreous layer of the Japanese pearl oyster Pinctada fucata, and its cleavage products (named pfPif97 and pfPif80 proteins were found to bind to the chitin framework and induce aragonite crystal formation and orient the c axis. In this study, a homologue of pfPif177 was cloned from the mantle of the Pacific oyster Crassostrea gigas, containing the homologue of pfPif97 only and not pfPif80. This finding hints at the large divergence in gene structure between the two species. This homologue (cgPif97 shares characteristics with pfPif97, and suggests that the biological functions of these two proteins may be similar. The expression pattern of cgPif97 in different tissues and development stages indicates that it may play an important role in shell formation of the adult oyster. The morphology of the inner shell surface was affected by injected siRNA of cgPif97 and the calcite laths of the shell became thinner and narrower when the siRNA dose increased, suggesting that the cgPif97 gene plays an important role in calcite shell formation in C. gigas. In conclusion, we found evidence that the Pif177 gene evolved very fast but still retains a similar function among species [Current Zoology 59 (1: 109–115, 2013].

O-GlcNAcylation of master growth repressor DELLA by SECRET AGENT modulates multiple signaling pathways in Arabidopsis.

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Zentella, Rodolfo; Hu, Jianhong; Hsieh, Wen-Ping; Matsumoto, Peter A; Dawdy, Andrew; Barnhill, Benjamin; Oldenhof, Harriëtte; Hartweck, Lynn M; Maitra, Sushmit; Thomas, Stephen G; Cockrell, Shelley; Boyce, Michael; Shabanowitz, Jeffrey; Hunt, Donald F; Olszewski, Neil E; Sun, Tai-Ping

2016-01-15

The DELLA family of transcription regulators functions as master growth repressors in plants by inhibiting phytohormone gibberellin (GA) signaling in response to developmental and environmental cues. DELLAs also play a central role in mediating cross-talk between GA and other signaling pathways via antagonistic direct interactions with key transcription factors. However, how these crucial protein-protein interactions can be dynamically regulated during plant development remains unclear. Here, we show that DELLAs are modified by the O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) SECRET AGENT (SEC) in Arabidopsis. O-GlcNAcylation of the DELLA protein REPRESSOR OF ga1-3 (RGA) inhibits RGA binding to four of its interactors-PHYTOCHROME-INTERACTING FACTOR3 (PIF3), PIF4, JASMONATE-ZIM DOMAIN1, and BRASSINAZOLE-RESISTANT1 (BZR1)-that are key regulators in light, jasmonate, and brassinosteroid signaling pathways, respectively. Consistent with this, the sec-null mutant displayed reduced responses to GA and brassinosteroid and showed decreased expression of several common target genes of DELLAs, BZR1, and PIFs. Our results reveal a direct role of OGT in repressing DELLA activity and indicate that O-GlcNAcylation of DELLAs provides a fine-tuning mechanism in coordinating multiple signaling activities during plant development. © 2016 Zentella et al.; Published by Cold Spring Harbor Laboratory Press.

Hormonal networks involved in apical hook development in darkness and their response to light

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Maria Agustina Mazzella

2014-02-01

Full Text Available In darkness, the dicot seedlings produces an apical hook as result of differential cell division and extension at opposite sides of the hypocotyl. This hook protects the apical meristem from mechanical damage during seedling emergence from the soil. In darkness, gibberellins act via the DELLA-PIF (PHYTOCHROME INTERACTING FACTORs pathway, and ethylene acts via the EIN3/EIL1 (ETHYLENE INSENSITIE 3/EIN3 like 1-HLS1 (HOOKLESS 1 pathway to control the asymmetric accumulation of auxin required for apical hook formation and maintenance. These core pathways form a network with multiple points of connection. Light perception by phytochromes and cryptochromes reduces the activity of PIFs and CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1 --both required for hook formation in darkness--, lowers the levels of gibberellins, and triggers hook opening as a component of the switch between heterotrophic and photoautotrophic development. Apical hook opening is thus a suitable model to study the convergence of endogenous and exogenous signals on the control of cell division and cell growth.

Automated dual-wavelength spectrophotometer optimized for phytochrome assay

International Nuclear Information System (INIS)

Pratt, L.H.; Wampler, J.E.; Rich, E.S. Jr.

1985-01-01

A microcomputer-controlled dual-wavelength spectrophotometer suitable for automated phytochrome assay is described. The optomechanical unit provides for sequential irradiation of the sample by the two measuring wavelengths with intervening dark intervals and for actinic irradiation to interconvert phytochrome between its two forms. Photomultiplier current is amplified, converted to a digital value and transferred into the computer using a custom-designed IEEE-488 bus interface. The microcomputer calculates mathematically both absorbance and absorbance difference values with dynamic correction for photomultiplier dark current. In addition, the computer controls the operating parameters of the spectrophotometer via a separate interface. These parameters include control of the durations of measuring and actinic irradiation intervals and their sequence. 14 references, 4 figures

Adaptive PIF control for permanent magnet synchronous motors based on GPC.

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Lu, Shaowu; Tang, Xiaoqi; Song, Bao

2012-12-24

To enhance the control performance of permanent magnet synchronous motors (PMSMs), a generalized predictive control (GPC)-based proportional integral feedforward (PIF) controller is proposed for the speed control system. In this new approach, firstly, based on the online identification of controlled model parameters, a simplified GPC law supplies the PIF controller with suitable control parameters according to the uncertainties in the operating conditions. Secondly, the speed reference curve for PMSMs is usually required to be continuous and continuously differentiable according to the general servo system design requirements, so the adaptation of the speed reference is discussed in details in this paper. Hence, the performance of the speed control system using a GPC-based PIF controller is improved for tracking some specified signals. The main motivation of this paper is the extension of GPC law to replace the traditional PI or PIF controllers in industrial applications. The efficacy and usefulness of the proposed controller are verified through experimental results.

Adaptive PIF Control for Permanent Magnet Synchronous Motors Based on GPC

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Shaowu Lu

2012-12-01

Full Text Available To enhance the control performance of permanent magnet synchronous motors (PMSMs, a generalized predictive control (GPC-based proportional integral feedforward (PIF controller is proposed for the speed control system. In this new approach, firstly, based on the online identification of controlled model parameters, a simplified GPC law supplies the PIF controller with suitable control parameters according to the uncertainties in the operating conditions. Secondly, the speed reference curve for PMSMs is usually required to be continuous and continuously differentiable according to the general servo system design requirements, so the adaptation of the speed reference is discussed in details in this paper. Hence, the performance of the speed control system using a GPC-based PIF controller is improved for tracking some specified signals. The main motivation of this paper is the extension of GPC law to replace the traditional PI or PIF controllers in industrial applications. The efficacy and usefulness of the proposed controller are verified through experimental results.

Characterization of peanut phytochromes and their possible regulating roles in early peanut pod development.

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Ye Zhang

Full Text Available Arachis hypogaea L. geocarpy is a unique feature different from other legume plants. Flowering and fertilization occur above ground, while the following processes of pod formation and development proceed in the soil. The zygote divides only few times to develop into pre-embryo and then further embryo developmental process stops when the gynoecium is exposed to light condition or normal day/night period. In this study, eight phytochrome genes were identified in two wild peanuts (four in Arachis duranensis and four in Arachis ipaensis. Using RACE and homologous cloning, the full CDS of AhphyA, AhphyA-like, AhphyB and AhphyE were acquired in cultivated peanut. Protein structure analysis showed that the conservative coding domains of phytochromes from a number of other plant species were found in these proteins. The C-terminal of AhphyA, AhphyA-like and AhphyB could interact with phytochrome-interacting factor 3 in vitro. The expression patterns of these genes in various tissues were analyzed by qRT-PCR, and significant differences were observed. Interestingly, the expression levels of AhphyA-like changed significantly during gynophore growth and early pod development. Furthermore, protein accumulation patterns of AhphyA and AhphyB in gynophore were different during early pod development stages in that AhphyA and AhphyB proteins were not detected in S1 and S2 gynophores, while significant accumulation of AhphyA and AhphyB were detected in S3 gynophore. These results provided evidence that phytochromes mediated light signal transduction may play key roles in peanut geocarpy development.

Molecular mechanisms and ecological function of far-red light signalling.

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Sheerin, David J; Hiltbrunner, Andreas

2017-11-01

Land plants possess the ability to sense and respond to far-red light (700-760 nm), which serves as an important environmental cue. Due to the nature of far-red light, it is not absorbed by chlorophyll and thus is enriched in canopy shade and will also penetrate deeper into soil than other visible wavelengths. Far-red light responses include regulation of seed germination, suppression of hypocotyl growth, induction of flowering and accumulation of anthocyanins, which depend on one member of the phytochrome photoreceptor family, phytochrome A (phyA). Here, we review the current understanding of the underlying molecular mechanisms of how plants sense far-red light through phyA and the physiological responses to this light quality. Light-activated phytochromes act on two primary pathways within the nucleus; suppression of the E3 ubiquitin ligase complex CUL4/DDB1 COP1/SPA and inactivation of the PHYTOCHROME INTERACTING FACTOR (PIF) family of bHLH transcription factors. These pathways integrate with other signal transduction pathways, including phytohormones, for tissue and developmental stage specific responses. Unlike other phytochromes that mediate red-light responses, phyA is transported from the cytoplasm to the nucleus in far-red light by the shuttle proteins FAR-RED ELONGATED HYPOCOTYL 1 (FHY1) and FHY1-LIKE (FHL). However, additional mechanisms must exist that shift the action of phyA to far-red light; current hypotheses are discussed. © 2017 John Wiley & Sons Ltd.

A plant EPF-type zinc-finger protein, CaPIF1, involved in defence against pathogens.

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Oh, Sang-Keun; Park, Jeong Mee; Joung, Young Hee; Lee, Sanghyeob; Chung, Eunsook; Kim, Soo-Yong; Yu, Seung Hun; Choi, Doil

2005-05-01

SUMMARY To understand better the defence responses of plants to pathogen attack, we challenged hot pepper plants with bacterial pathogens and identified transcription factor-encoding genes whose expression patterns were altered during the subsequent hypersensitive response. One of these genes, CaPIF1 (Capsicum annuum Pathogen-Induced Factor 1), was characterized further. This gene encodes a plant-specific EPF-type protein that contains two Cys(2)/His(2) zinc fingers. CaPIF1 expression was rapidly and specifically induced when pepper plants were challenged with bacterial pathogens to which they are resistant. In contrast, challenge with a pathogen to which the plants are susceptible only generated weak CaPIF1 expression. CaPIF1 expression was also strongly induced in pepper leaves by the exogenous application of ethephon, an ethylene-releasing compound, and salicylic acid, whereas methyl jasmonate had only moderate effects. CaPIF1 localized to the nuclei of onion epidermis when expressed as a CaPIF1-smGFP fusion protein. Transgenic tobacco plants over-expressing CaPIF1 driven by the CaMV 35S promoter showed increased resistance to challenge with a tobacco-specific pathogen or non-host bacterial pathogens. These plants also showed constitutive up-regulation of multiple defence-related genes. Moreover, virus-induced silencing of the CaPIF1 orthologue in Nicotiana benthamiana enhanced susceptibility to the same host or non-host bacterial pathogens. These observations provide evidence that an EPF-type Cys(2)/His(2) zinc-finger protein plays a crucial role in the activation of the pathogen defence response in plants.

Minimal domain of bacterial phytochrome required for chromophore binding and fluorescence

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Rumyantsev, Konstantin A.; Shcherbakova, Daria M.; Zakharova, Natalia I.; Emelyanov, Alexander V.; Turoverov, Konstantin K.; Verkhusha, Vladislav V.

2015-12-01

Fluorescent proteins (FP) are used to study various biological processes. Recently, a series of near-infrared (NIR) FPs based on bacterial phytochromes was developed. Finding ways to improve NIR FPs is becoming progressively important. By applying rational design and molecular evolution we have engineered R. palustris bacterial phytochrome into a single-domain NIR FP of 19.6 kDa, termed GAF-FP, which is 2-fold and 1.4-fold smaller than bacterial phytochrome-based NIR FPs and GFP-like proteins, respectively. Engineering of GAF-FP involved a substitution of 15% of its amino acids and a deletion of the knot structure. GAF-FP covalently binds two tetrapyrrole chromophores, biliverdin (BV) and phycocyanobilin (PCB). With the BV chromophore GAF-FP absorbs at 635 nm and fluoresces at 670 nm. With the PCB chromophore GAF-FP becomes blue-shifted and absorbs at 625 nm and fluoresces at 657 nm. The GAF-FP structure has a high tolerance to small peptide insertions. The small size of GAF-FP and its additional absorbance band in the violet range has allowed for designing a chimeric protein with Renilla luciferase. The chimera exhibits efficient non-radiative energy transfer from luciferase to GAF-FP, resulting in NIR bioluminescence. This study opens the way for engineering of small NIR FPs and NIR luciferases from bacterial phytochromes.

Novel Photodynamics in Phytochrome & Cyanobacteriochrome Photosensory Proteins

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Larsen, Delmar

2015-03-01

The photodynamics of recently characterized phytochrome and cyanobacteriochrome photoreceptors are discussed. Phytochromes are red/far-red photosensory proteins that utilize the photoisomerization of a linear tetrapyrrole (bilin) chromophore to detect the red to far-red light ratio. Cyanobacteriochromes (CBCRs) are distantly related cyanobacterial photosensors with homologous bilin-binding GAF domains, but exhibit greater spectral diversity. The excited-state mechanisms underlying the initial photoisomerization in the forward reactions of the cyanobacterial photoreceptor Cph1 from Synechocystis, the RcaE CBCR from Fremyella diplosiphon, and Npr6012g4 CBCR from Nostoc punctiforme were contrasted via multipulse pump-dump-probe transient spectroscopy. A rich excited-state dynamics are resolved involving a complex interplay of excited-state proton transfer, photoisomerization, multilayered inhomogeneity, and reactive intermediates, and Le Chatelier redistribution. NpR6012g4 exhibits a high quantum yield for its forward photoreaction (40%) that was ascribed to the activity of hidden, productive ground-state intermediates via a ``second chance initiation dynamics'' (SCID) mechanism. This work was supported by a grant from the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, United States Department of Energy (DOE DE-FG02-09ER16117).

Particle-bound phytochrome: differential pigment release by surfactants, ribonuclease and phospholipase C

International Nuclear Information System (INIS)

Gressel, J.; Quail, P.H.

1976-01-01

Surfactants and hydrolytic enzymes were used to probe the nature of the constituent(s) to which phytochrome binds in particulate fractions from red-irradiated Cucurbita, [ 14 C]-choline and [ 3 H]-uridine pre-labelled tissue was used to monitor the release of phospholipids and RNA by these agents. Ribonuclease (RNase) digestion of 20,000 x g pellets eliminates both the phytochrome and ribonucleprotein (RNP) which cosediment at 31S. Little [ 14 C]-choline occurs in the 31S fraction and the amount is not changed by RNase digestion. This is further evidence that phytochrome binds directly to the RNP in the 31S fraction rather than to any membranous material present. The distribution profile of the RNA in a second (='heavy') phytochrome fraction does not correlate with that of the pigment. This suggests that the phytochrome in this fraction is not bound to RNP. The RNA is of ribosomal origin but much less degraded than that of the 31S RNP and is resistant to RNase digestion. Phospholipase C releases 80% of the [ 14 C]-choline from the 'heavy' fraction without freeing phytochrome. This indicates that the pigment does not bind to the polar head groups of the membrane phospholipids present. Low concentrations of deoxycholate dissociate phytochrome from this fraction without releasing substantial quantities of integral membrane proteins or phospholipids. Some RNP is dislodged by the surfactant but the phytochrome and RNP are not released as a complex. The data suggest that the pigment in the 'heavy' fraction may be loosely bound to a protein constituent rather than to RNP or polar phospholipids. (auth.)

Phytochrome quantitation in crude extracts of Avena by enzyme-linked immunosorbent assay with monoclonal antibodies

Energy Technology Data Exchange (ETDEWEB)

Shimazaki, Y; Cordonnier, M M; Pratt, L H

1983-01-01

An enzyme-linked immunosorbent assay (ELISA), which uses both rabbit polyclonal and mouse monoclonal antibodies to phytochrome, has been adapted for quantitation of phytochrome in crude plant extracts. The assay has a detection limit of about 100 pg phytochrome and can be completed within 10 h. Quantitation of phytochrome in crude extracts of etiolated oat seedlings by ELISA gave values that agreed well with those obtained by spectrophotometric assay. When etiolated oat seedlings were irradiated continuously for 24 h, the amount of phytochrome detected by ELISA and by spectrophotometric assay decreased by more than 1000-fold and about 100-fold, respectively. This discrepancy indicates that phytochrome in light-treated plants may be antigenically distinct from that found in fully etiolated plants. When these light-grown oat seedlings were kept in darkness for 48 h, phytochrome content detected by ELISA increased by 50-fold in crude extracts of green oat shoots, but only about 12-fold in extracts of herbicide-treated oat shoots. Phytochrome reaccumulation in green oat shoots was initially more rapid in the more mature cells of the primary leaf tip than near the basal part of the shoot. The inhibitory effect of Norflurazon on phytochrome accumulation was much more evident near the leaf tip than the shoot base. A 5-min red irradiation of oat seedlings at the end of a 48-h dark period resulted in a subsequent, massive decrease in phytochrome content in crude extracts from both green and Norflurazon-bleached oat shoots. These observations eliminate the possibility that substantial accumulation of chromophore-free phytochrome was being detected and indicate that Norflurazon has a substantial effect on phytochrome accumulation during a prolonged dark period. 25 references, 9 figures, 3 tables.

Chlorophyll formation and phytochrome

NARCIS (Netherlands)

Raven, C.W.

1973-01-01

The rôle of phytochrome in the regeneration of protochlorophyll (Pchl) in darkness following short exposures to light, as well as in the accumulation of chlorophyll- a (Chl- a ) in continuous light in previously dark-grown seedlings of pea, bean,

Biphasic Fluence-Response Curves for Phytochrome-Mediated Kalanchoë Seed Germination 1

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Rethy, Roger; Dedonder, Andrée; De Petter, Edwin; Van Wiemeersch, Luc; Fredericq, Henri; De Greef, Jan; Steyaert, Herman; Stevens, Hilde

1987-01-01

The fluence-response curves for the effect of two red pulses separated by 24 hours on the germination of Kalanchoe blossfeldiana Poelln. cv Vesuv seeds, incubated on gibberellic acid (GA3) are biphasic for suboptimal concentrations. The response in the low fluence range corresponds with a classical red/far-red reversible phytochrome mediated reaction. GA3 induces an additional response in the very low fluence range, which is also phytochrome mediated. The sensitivity to phytochrome-far-red absorbing form (Pfr), however, is increased about 20,000-fold, so that even far-red fluences become saturating. Both in the very low and low fluence response range, the maximal responses induced by saturating fluences are modulated by the GA3 concentration. GA3 having no direct influence on the phytochrome phototransformations, alters the Pfr requirement and determines the responding seed population fraction in the very low and low fluence range. The effet of GA3 appears to be on the transduction chain of the phytochrome signal. PMID:16665187

Expression Patterns of OsPIL11, a Phytochrome-Interacting Factor in Rice, and Preliminary Analysis of Its Roles in Light Signal Transduction

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Li LI

2012-12-01

Full Text Available The expression patterns of OsPIL11, one of six putative phytochrome-interacting factors, were analyzed in different organs of transgenic tobacco (Nicotiana tabacum. The expression of OsPIL11 was organ-specific and was regulated by leaf development, abscisic acid (ABA, jasmonic acid (JA and salicylic acid (SA. To further explore the role of OsPIL11 in plant light signal transduction, a plant expression vector of OsPIL11 was constructed and introduced into tobacco. When grown under continuous red light, OsPIL11-overexpressed transgenic tobacco exhibited shorter hypocotyls and larger cotyledons and leaves compared to wild-type seedlings. When grown under continuous far-red light, however, transgenic and wild-type seedlings showed similar phenotypes. These results indicate that OsPIL11 is involved in red light induced de-etiolation, but not in far-red light induced de-etiolation in transgenic tobacco, which lays the foundation for dissecting the function of OsPIL11 in phytochrome-mediated light signal transduction in rice.

A computational approach to discovering the functions of bacterial phytochromes by analysis of homolog distributions

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Lamparter Tilman

2006-03-01

Full Text Available Abstract Background Phytochromes are photoreceptors, discovered in plants, that control a wide variety of developmental processes. They have also been found in bacteria and fungi, but for many species their biological role remains obscure. This work concentrates on the phytochrome system of Agrobacterium tumefaciens, a non-photosynthetic soil bacterium with two phytochromes. To identify proteins that might share common functions with phytochromes, a co-distribution analysis was performed on the basis of protein sequences from 138 bacteria. Results A database of protein sequences from 138 bacteria was generated. Each sequence was BLASTed against the entire database. The homolog distribution of each query protein was then compared with the homolog distribution of every other protein (target protein of the same species, and the target proteins were sorted according to their probability of co-distribution under random conditions. As query proteins, phytochromes from Agrobacterium tumefaciens, Pseudomonas aeruginosa, Deinococcus radiodurans and Synechocystis PCC 6803 were chosen along with several phytochrome-related proteins from A. tumefaciens. The Synechocystis photosynthesis protein D1 was selected as a control. In the D1 analyses, the ratio between photosynthesis-related proteins and those not related to photosynthesis among the top 150 in the co-distribution tables was > 3:1, showing that the method is appropriate for finding partner proteins with common functions. The co-distribution of phytochromes with other histidine kinases was remarkably high, although most co-distributed histidine kinases were not direct BLAST homologs of the query protein. This finding implies that phytochromes and other histidine kinases share common functions as parts of signalling networks. All phytochromes tested, with one exception, also revealed a remarkably high co-distribution with glutamate synthase and methionine synthase. This result implies a general role of

Raffinose family oligosaccharides act as galactose stores in seeds and are required for rapid germination of Arabidopsis in the dark

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Roman Gangl

2016-07-01

Full Text Available Raffinose synthase 5 (AtRS5, At5g40390 was characterized from Arabidopsis as a recombinant enzyme. It has a far higher affinity for the substrates galactinol and sucrose than any other raffinose synthase previously reported. In addition raffinose synthase 5 is also working as a galactosylhydrolase, degrading galactinol and raffinose under certain conditions. Together with raffinose synthase 4, which is predominantly a stachyose synthase, both enzymes contribute to the raffinose family oligosaccharide (RFO accumulation in seeds. A double knockout in raffinose synthase 4 and raffinose synthase 5 (ΔAtRS4,5 was generated, which is devoid of RFOs in seeds. Unstressed leaves of 4 week old ΔAtRS4,5 plants showed drastically 23.8-fold increased concentrations of galactinol. Unexpectedly, raffinose appeared again in drought stressed ΔAtRS4,5 plants, but not under other abiotic stress conditions. Drought stress leads to novel transcripts of raffinose synthase 6 suggesting that this isoform is a further stress inducible raffinose synthase in Arabidopsis. ΔAtRS4,5 seeds showed a 5 days delayed germination phenotype in darkness and an elevated expression of the transcription factor phytochrome interacting factor 1 (AtPIF1 target gene AtPIF6, being a repressor of germination. This prolonged dormancy is not seen during germination in the light. Exogenous galactose partially promotes germination of ΔAtRS4,5 seeds in the dark suggesting that RFOs act as a galactose store and repress AtPIF6 transcripts.

Phytochrome and greening in etioplasts

NARCIS (Netherlands)

Kraak, H.L.

1986-01-01

This thesis is concerned with the role played by phytochrome (P) in the development of etioplasts into chloroplasts.

Previously dark-grown maize seedlings are not as sensitive as pea seedlings to very low fluences of red light (R) with regard to induction of rapid chlorophyll (Chl)

A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

KAUST Repository

Meier, Stuart; Tzfadia, Oren; Vallabhaneni, Ratnakar; Gehring, Christoph A; Wurtzel, Eleanore T

2011-01-01

Background: The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana.Results: A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR) but was inhibited by abscisic acid (ABA). Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs) and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced and uncoupled from that of

A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

KAUST Repository

Meier, Stuart

2011-05-19

Background: The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana.Results: A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR) but was inhibited by abscisic acid (ABA). Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs) and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced and uncoupled from that of

A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

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Vallabhaneni Ratnakar

2011-05-01

Full Text Available Abstract Background The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana. Results A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR but was inhibited by abscisic acid (ABA. Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced

ASTRO-H CdTe detectors proton irradiation at PIF

International Nuclear Information System (INIS)

Limousin, O.; Renaud, D.; Horeau, B.; Dubos, S.; Laurent, P.; Lebrun, F.; Chipaux, R.; Boatella Polo, C.; Marcinkowski, R.; Kawaharada, M.; Watanabe, S.; Ohta, M.; Sato, G.; Takahashi, T.

2015-01-01

Asbstract: The French Atomic Energy Commission (CEA), with the support of the European Space Agency (ESA), is partner of the Soft Gamma-Ray Detector (SGD) and the Hard X-ray Imager (HXI) onboard the 6th Japanese X-ray scientific satellite ASTRO-H (JAXA) initiated by the Institute of Space and Astronautical Science (ISAS). Both scientific instruments, one hosting a series of Compton Gamma Cameras and the other being a focal plane of a grazing incidence mirror telescope in the hard X-ray domain, are equipped with Cadmium Telluride based detectors. ASTRO-H will be operated in a Low Earth Orbit with a 31° inclination at ~550 km altitude, thus passing daily through the South Atlantic Anomaly radiation belt, a specially harsh environment where the detectors are suffering the effect of the interaction with trapped high energy protons. As CdTe detector performance might be affected by the irradiation, we investigate the effect of the accumulated proton fluence on their spectral response. To do so, we have characterized and irradiated representative samples of SGD and HXI detector under different conditions. The detectors in question, from ACRORAD, are single-pixels having a size of 2 mm by 2 mm and 750 µm thick. The Schottky contact is either made of an Indium or Aluminum for SGD and HXI respectively. We ran the irradiation test campaign at the Proton Irradiation Facility (PIF) at PSI, and ESA approved equipment to evaluate the radiation hardness of flight hardware. We simulated the proton flux expected on the sensors over the entire mission, and secondary neutrons flux due to primary proton interactions into the surrounding BGO active shielding. We eventually characterized the detector response evolution, emphasizing each detector spectral response as well as its stability by studying the so-called Polarization effect. The latter is provoking a spectral response degradation against time as a charge accumulation process occurs in Schottky type CdTe sensors. In this paper

Ubiquitous Structural Signaling in Bacterial Phytochromes

NARCIS (Netherlands)

Björling, Alexander; Berntsson, Oskar; Takala, Heikki; Gallagher, Kevin D.; Patel, Hardik; Gustavsson, Emil; St. Peter, Rachael; Duong, Phu; Nugent, Angela; Zhang, Fan; Berntsen, Peter; Appio, Roberto; Rajkovic, Ivan; Lehtivuori, Heli; Panman, Matthijs R.; Hoernke, Maria; Niebling, Stephan; Harimoorthy, Rajiv; Lamparter, Tilman; Stojković, Emina A.; Ihalainen, Janne A.; Westenhoff, Sebastian

2015-01-01

The phytochrome family of light-switchable proteins has long been studied by biochemical, spectroscopic and crystallographic means, while a direct probe for global conformational signal propagation has been lacking. Using solution X-ray scattering, we find that the photosensory cores of several

UV-B Perceived by the UVR8 Photoreceptor Inhibits Plant Thermomorphogenesis.

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Hayes, Scott; Sharma, Ashutosh; Fraser, Donald P; Trevisan, Martine; Cragg-Barber, C Kester; Tavridou, Eleni; Fankhauser, Christian; Jenkins, Gareth I; Franklin, Keara A

2017-01-09

Small increases in ambient temperature can elicit striking effects on plant architecture, collectively termed thermomorphogenesis [1]. In Arabidopsis thaliana, these include marked stem elongation and leaf elevation, responses that have been predicted to enhance leaf cooling [2-5]. Thermomorphogenesis requires increased auxin biosynthesis, mediated by the bHLH transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) [6-8], and enhanced stability of the auxin co-receptor TIR1, involving HEAT SHOCK PROTEIN 90 (HSP90) [9]. High-temperature-mediated hypocotyl elongation additionally involves localized changes in auxin metabolism, mediated by the indole-3-acetic acid (IAA)-amido synthetase Gretchen Hagen 3 (GH3).17 [10]. Here we show that ultraviolet-B light (UV-B) perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8) [11] strongly attenuates thermomorphogenesis via multiple mechanisms inhibiting PIF4 activity. Suppression of thermomorphogenesis involves UVR8 and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1)-mediated repression of PIF4 transcript accumulation, reducing PIF4 abundance. UV-B also stabilizes the bHLH protein LONG HYPOCOTYL IN FAR RED (HFR1), which can bind to and inhibit PIF4 function. Collectively, our results demonstrate complex crosstalk between UV-B and high-temperature signaling. As plants grown in sunlight would most likely experience concomitant elevations in UV-B and ambient temperature, elucidating how these pathways are integrated is of key importance to the understanding of plant development in natural environments. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Biphasic fluence-response curves for phytochrome-mediated kalanchoë seed germination : sensitization by gibberellic Acid.

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Rethy, R; Dedonder, A; De Petter, E; Van Wiemeersch, L; Fredericq, H; De Greef, J; Steyaert, H; Stevens, H

1987-01-01

The fluence-response curves for the effect of two red pulses separated by 24 hours on the germination of Kalanchoe blossfeldiana Poelln. cv Vesuv seeds, incubated on gibberellic acid (GA(3)) are biphasic for suboptimal concentrations. The response in the low fluence range corresponds with a classical red/far-red reversible phytochrome mediated reaction. GA(3) induces an additional response in the very low fluence range, which is also phytochrome mediated. The sensitivity to phytochrome-far-red absorbing form (Pfr), however, is increased about 20,000-fold, so that even far-red fluences become saturating. Both in the very low and low fluence response range, the maximal responses induced by saturating fluences are modulated by the GA(3) concentration. GA(3) having no direct influence on the phytochrome phototransformations, alters the Pfr requirement and determines the responding seed population fraction in the very low and low fluence range. The effet of GA(3) appears to be on the transduction chain of the phytochrome signal.

TbPIF5 is a Trypanosoma brucei mitochondrial DNA helicase involved in processing of minicircle Okazaki fragments.

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Beiyu Liu

2009-09-01

Full Text Available Trypanosoma brucei's mitochondrial genome, kinetoplast DNA (kDNA, is a giant network of catenated DNA rings. The network consists of a few thousand 1 kb minicircles and several dozen 23 kb maxicircles. Here we report that TbPIF5, one of T. brucei's six mitochondrial proteins related to Saccharomyces cerevisiae mitochondrial DNA helicase ScPIF1, is involved in minicircle lagging strand synthesis. Like its yeast homolog, TbPIF5 is a 5' to 3' DNA helicase. Together with other enzymes thought to be involved in Okazaki fragment processing, TbPIF5 localizes in vivo to the antipodal sites flanking the kDNA. Minicircles in wild type cells replicate unidirectionally as theta-structures and are unusual in that Okazaki fragments are not joined until after the progeny minicircles have segregated. We now report that overexpression of TbPIF5 causes premature removal of RNA primers and joining of Okazaki fragments on theta structures. Further elongation of the lagging strand is blocked, but the leading strand is completed and the minicircle progeny, one with a truncated H strand (ranging from 0.1 to 1 kb, are segregated. The minicircles with a truncated H strand electrophorese on an agarose gel as a smear. This replication defect is associated with kinetoplast shrinkage and eventual slowing of cell growth. We propose that TbPIF5 unwinds RNA primers after lagging strand synthesis, thus facilitating processing of Okazaki fragments.

G-quadruplex and G-rich sequence stimulate Pif1p-catalyzed downstream duplex DNA unwinding through reducing waiting time at ss/dsDNA junction

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Zhang, Bo; Wu, Wen-Qiang; Liu, Na-Nv; Duan, Xiao-Lei; Li, Ming; Dou, Shuo-Xing; Hou, Xi-Miao; Xi, Xu-Guang

2016-01-01

Alternative DNA structures that deviate from B-form double-stranded DNA such as G-quadruplex (G4) DNA can be formed by G-rich sequences that are widely distributed throughout the human genome. We have previously shown that Pif1p not only unfolds G4, but also unwinds the downstream duplex DNA in a G4-stimulated manner. In the present study, we further characterized the G4-stimulated duplex DNA unwinding phenomenon by means of single-molecule fluorescence resonance energy transfer. It was found that Pif1p did not unwind the partial duplex DNA immediately after unfolding the upstream G4 structure, but rather, it would dwell at the ss/dsDNA junction with a ‘waiting time’. Further studies revealed that the waiting time was in fact related to a protein dimerization process that was sensitive to ssDNA sequence and would become rapid if the sequence is G-rich. Furthermore, we identified that the G-rich sequence, as the G4 structure, equally stimulates duplex DNA unwinding. The present work sheds new light on the molecular mechanism by which G4-unwinding helicase Pif1p resolves physiological G4/duplex DNA structures in cells. PMID:27471032

The Arabidopsis SWI/SNF protein BAF60 mediates seedling growth control by modulating DNA accessibility

KAUST Repository

Jé gu, Teddy; Veluchamy, Alaguraj; Ramirez Prado, Juan Sebastian; Rizzi-Paillet, Charley; Perez, Magalie; Lhomme, Anaï s; Latrasse, David; Coleno, Emeline; Vicaire, Serge; Legras, Sté phanie; Jost, Bernard; Rougé e, Martin; Barneche, Fredy; Bergounioux, Catherine; Crespi, Martin; Mahfouz, Magdy M.; Hirt, Heribert; Raynaud, Cé cile; Benhamed, Moussa

2017-01-01

Plant adaptive responses to changing environments involve complex molecular interplays between intrinsic and external signals. Whilst much is known on the signaling components mediating diurnal, light, and temperature controls on plant development, their influence on chromatin-based transcriptional controls remains poorly explored.In this study we show that a SWI/SNF chromatin remodeler subunit, BAF60, represses seedling growth by modulating DNA accessibility of hypocotyl cell size regulatory genes. BAF60 binds nucleosome-free regions of multiple G box-containing genes, opposing in cis the promoting effect of the photomorphogenic and thermomorphogenic regulator Phytochrome Interacting Factor 4 (PIF4) on hypocotyl elongation. Furthermore, BAF60 expression level is regulated in response to light and daily rhythms.These results unveil a short path between a chromatin remodeler and a signaling component to fine-tune plant morphogenesis in response to environmental conditions.

The Arabidopsis SWI/SNF protein BAF60 mediates seedling growth control by modulating DNA accessibility

KAUST Repository

Jégu, Teddy

2017-06-15

Plant adaptive responses to changing environments involve complex molecular interplays between intrinsic and external signals. Whilst much is known on the signaling components mediating diurnal, light, and temperature controls on plant development, their influence on chromatin-based transcriptional controls remains poorly explored.In this study we show that a SWI/SNF chromatin remodeler subunit, BAF60, represses seedling growth by modulating DNA accessibility of hypocotyl cell size regulatory genes. BAF60 binds nucleosome-free regions of multiple G box-containing genes, opposing in cis the promoting effect of the photomorphogenic and thermomorphogenic regulator Phytochrome Interacting Factor 4 (PIF4) on hypocotyl elongation. Furthermore, BAF60 expression level is regulated in response to light and daily rhythms.These results unveil a short path between a chromatin remodeler and a signaling component to fine-tune plant morphogenesis in response to environmental conditions.

Ambient temperature signalling in plants.

Science.gov (United States)

Wigge, Philip A

2013-10-01

Plants are exposed to daily and seasonal fluctuations in temperature. Within the 'ambient' temperature range (about 12-27°C for Arabidopsis) temperature differences have large effects on plant growth and development, disease resistance pathways and the circadian clock without activating temperature stress pathways. It is this developmental sensing and response to non-stressful temperatures that will be covered in this review. Recent advances have revealed key players in mediating temperature signals. The bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) has been shown to be a hub for multiple responses to warmer temperature in Arabidopsis, including flowering and hypocotyl elongation. Changes in chromatin state are involved in transmitting temperature signals to the transcriptome. Determining the precise mechanisms of temperature perception represents an exciting goal for the field. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cryptochrome and phytochrome cooperatively but independently reduce active gibberellin content in rice seedlings under light irradiation.

Science.gov (United States)

Hirose, Fumiaki; Inagaki, Noritoshi; Hanada, Atsushi; Yamaguchi, Shinjiro; Kamiya, Yuji; Miyao, Akio; Hirochika, Hirohiko; Takano, Makoto

2012-09-01

In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4-OsGA2ox7). For further examination of the regulation of these genes, we established a series of cryptochrome-deficient lines through reverse genetic screening from a Tos17 mutant population and construction of knockdown lines based on an RNA interference technique. By using these lines and phytochrome mutants, we elucidated that cryptochrome 1 (cry1), consisting of two species in rice plants (cry1a and cry1b), is indispensable for robust induction of the GA2ox genes. On the other hand, repression of the GA20ox genes is mediated by phytochromes. In addition, we found that the phytochromes also mediate the repression of a gibberellin 3-oxidase gene (OsGA3ox2) in the light. These results imply that, in rice seedlings, phytochromes mediate the repression of gibberellin biosynthesis capacity, while cry1 mediates the induction of gibberellin inactivation capacity. The cry1 action was demonstrated to be dominant in the reduction of active gibberellin content, but, in rice seedlings, the cumulative effects of these independent actions reduced active gibberellin content in the light. This pathway design in which different types of photoreceptors independently but cooperatively regulate active gibberellin content is unique from the viewpoint of dicot research. This redundancy should provide robustness to the response in rice plants.

Correlations between cultured pearl size parameters and PIF-177 biomarker expression in Pinctada margaritifera families reared in two contrasting environments

Science.gov (United States)

Blay, Carole; Parrad, Sophie; Cabral, Philippe; Aiho, Vaite; Ky, Chin-Long

2016-12-01

The black-lipped pearl oyster, Pinctada margaritifera, produces the largest and most valuable coloured pearls in the world. Cultured pearl size remains one of the most important quality traits. Despite the great geographical area covered by pearl farms in the atolls of French Polynesia, little is known about the influence of grow-out site effects on pearl size attained. To explore the genetic and environmental impact on the size of pearls as well as the genetic × environment interaction, a uniform experimental graft was designed on two contrasting macro-geographical lagoons. Five biparental families of donor oysters were grafted and then reared at both sites. After 18 months of culture, phenotypic parameters corresponding to pearl size, i.e. nacre weight and thickness, were recorded among the harvested pearls. The expression of Pif-177 gene, a biomarker encoding protein in the aragonite nacreous layer, was analysed in the corresponding pearl sac. The results show a family effect for nacre weight and thickness on both sites, with family F058 producing the heaviest and thickest nacre, and F805 the lightest and thinnest. By contrast, inter-site comparison revealed no significant site effects for these two parameters. In addition, grow-out location did not modify the relative gene expression of Pif-177 in the pearl sac between donor families in either culture site. Both nacre weight and thickness were positively correlated with the level gene expression of Pif-177. These results suggest that pearl size parameters were not affected by the environment in the present study and this is supported by the relative gene expression of Pif-177 observed. This knowledge constitutes an initial step in the study of pearl size trait inheritance, which will be helpful in the near future for the diffusion of genetically selected donor oyster lines produced by hatchery systems throughout production sites.

A homeodomain transcription factor gene, PfMSX, activates expression of Pif gene in the pearl oyster Pinctada fucata.

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Mi Zhao

Full Text Available We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs PfMSX binded to MSX consensus binding sites in the 5' flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster.

A Homeodomain Transcription Factor Gene, PfMSX, Activates Expression of Pif Gene in the Pearl Oyster Pinctada fucata

Science.gov (United States)

Zhao, Mi; He, Maoxian; Huang, Xiande; Wang, Qi

2014-01-01

We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs) PfMSX binded to MSX consensus binding sites in the 5′ flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster. PMID:25099698

A homeodomain transcription factor gene, PfMSX, activates expression of Pif gene in the pearl oyster Pinctada fucata.

Science.gov (United States)

Zhao, Mi; He, Maoxian; Huang, Xiande; Wang, Qi

2014-01-01

We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs) PfMSX binded to MSX consensus binding sites in the 5' flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster.

The Photoconversion of Phytochrome Includes an Unproductive Shunt Reaction Pathway.

Science.gov (United States)

Buhrke, David; Kuhlmann, Uwe; Michael, Norbert; Hildebrandt, Peter

2018-03-05

Phytochromes are modular bimodal photoswitches that control gene expression for morphogenetic processes in plants. These functions are triggered by photoinduced conversions between the inactive and active states of the photosensory module, denoted as Pr and Pfr, respectively. In the present time-resolved resonance Raman spectroscopic study of bacterial representatives of this photoreceptor family, we demonstrate that these phototransformations do not represent linear processes but include a branching reaction back to the initial state, prior to (de)activation of the output module. Thus, only a fraction of the photoreceptors undergoing the phototransformations can initiate the downstream signaling process, consistent with phytochrome's function as a sensor for more durable changes of light conditions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ca2+ transport in plant cells and mechanisms of transformation of phytochrome-induced photosignals

Science.gov (United States)

Volotovski, Igor D.

1995-01-01

The recent data on the influence of phytochrome on the efficiency of Ca2+ translocation across the membranes of oat protoplasts are given. Ca2+ uptake in the protoplasts was shown to be influenced by the red light (R) illumination. This effect was reverted by the following far-red light (FR) illumination. To elucidate the sensitivity to phytochrome-controlling action the screening between the mechanisms of Ca2+ transport across the plasma membranes of oat protoplasts, Na+/Ca2+ and Ca2+/H+ exchangers, Ca2+-pump and Ca2+-channel was done. It was established that phytochrome modulated the activity of Na+/Ca2+-exchanger and Ca2+-pump. The light-mediated oscillations of cytoplasmic Ca2+ concentration in the oat protoplasts were demonstrated using fluorescence probe quin2 loaded into the cells and laser monitoring of fluorescence signal. The evidences were obtained that the oscillations were not the result of the elevation of cytoplasmic Ca2+ concentration and had no connection with Ca2+ pool of mitochondria. The possibility of the relation between the Ca2+ oscillations and phosphoinositide metabolism in plant cell membranes is analyzed. The mechanisms of transformation of primary phytochrome signal into biological effects were discussed.

A genomewide screen for suppressors of Alu-mediated rearrangements reveals a role for PIF1.

Directory of Open Access Journals (Sweden)

Karen M Chisholm

Full Text Available Alu-mediated rearrangement of tumor suppressor genes occurs frequently during carcinogenesis. In breast cancer, this mechanism contributes to loss of the wild-type BRCA1 allele in inherited disease and to loss of heterozygosity in sporadic cancer. To identify genes required for suppression of Alu-mediated recombination we performed a genomewide screen of a collection of 4672 yeast gene deletion mutants using a direct repeat recombination assay. The primary screen and subsequent analysis identified 12 candidate genes including TSA, ELG1, and RRM3, which are known to play a significant role in maintaining genomic stability. Genetic analysis of the corresponding human homologs was performed in sporadic breast tumors and in inherited BRCA1-associated carcinomas. Sequencing of these genes in high risk breast cancer families revealed a potential role for the helicase PIF1 in cancer predisposition. PIF1 variant L319P was identified in three breast cancer families; importantly, this variant, which is predicted to be functionally damaging, was not identified in a large series of controls nor has it been reported in either dbSNP or the 1000 Genomes Project. In Schizosaccharomyces pombe, Pfh1 is required to maintain both mitochondrial and nuclear genomic integrity. Functional studies in yeast of human PIF1 L319P revealed that this variant cannot complement the essential functions of Pfh1 in either the nucleus or mitochondria. Our results provide a global view of nonessential genes involved in suppressing Alu-mediated recombination and implicate variation in PIF1 in breast cancer predisposition.

Modulation of phytochrome signaling networks for improved biomass accumulation using a bioenergy crop model

Energy Technology Data Exchange (ETDEWEB)

Mockler, Todd C. [Donald Danforth Plant Science Center, Saint Louis, MO (United States)

2016-11-07

Plant growth and development, including stem elongation, flowering time, and shade-avoidance habits, are affected by wavelength composition (i.e., light quality) of the light environment. the molecular mechanisms underlying light perception and signaling pathways in plants have been best characterized in Arabidopsis thaliana where dozens of genes have been implicated in converging, complementary, and antagonistic pathways communicating light quality cues perceived by the phytochrome (red/far-red) cryptochrome (blue) and phototropin (blue) photorecptors. Light perception and signaling have been studied in grasses, including rice and sorghum but in much less detail than in Arabidopsis. During the course of the Mocker lab's DOE-funded wrok generating a gene expression atlas in Brachypodium distachyon we observed that Brachypodium plants grown in continuous monochromatic red light or continuous white light enriched in far-red light accumulated significantly more biomass and exhibited significantly greater seed yield than plants grown in monochromatic blue light or white light. This phenomenon was also observed in two other grasses, switchgrass and rice. We will systematically manipulate the expression of genes predicted to function in Brachypodium phytochrome signaling and assess the phenotypic consequences in transgenic Brachypodium plants in terms of morphology, stature, biomass accumulation, and cell wall composition. We will also interrogate direct interactions between candidate phytochrome signaling transcription factors and target promoters using a high-throughput yeast one-hybrid system. Brachypodium distachyon has emerged as a model grass species and is closely related to candidate feedstock crops for bioethanol production. Identification of genes capable of modifying growth characteristics of Brachypodium, when misexpressed, in particular increasing biomass accumulation, by modulating photoreceptor signaling will provide valuable candidates for

Phytochrome-dependent coordinate control of distinct aspects of nuclear and plastid gene expression during anterograde signalling and photomorphogenesis

Directory of Open Access Journals (Sweden)

Sookyung eOh

2014-04-01

Full Text Available Light perception by photoreceptors impacts plastid transcription, development, and differentiation. This photoreceptor-dependent activity suggests a mechanism for photoregulation of gene expression in the nucleus and plastid that serves to coordinate expression of critical genes of these two organelles. This coordinate expression is required for proper stoichiometric accumulation of components needed for assembly of plastids, photosynthetic light-harvesting complexes and components such as phytochromes. Chloroplast-targeted sigma factors, which function together with the plastid-encoded RNA polymerase to regulate expression of plastid-encoded genes, and nuclear-encoded plastid development factors, such as GLK1 and GLK2, are targets of phytochrome regulation. Such phytochrome-dependent functions are hypothesized to allow light-dependent regulation, and feasibly tuning, of plastid components and function in response to changes in the external environment, which directly affects photosynthesis and the potential for light-induced damage. When the size and protein composition of the light-harvesting complexes are not tuned to the external environment, imbalances in electron transport can impact the cellular redox state and cause cellular damage. We show that phytochromes specifically regulate the expression of multiple factors that function to modulate plastid transcription and, thus, provide a paradigm for coordinate expression of the nuclear and plastid genomes in response to changes in external light conditions. As phytochromes respond to changes in the prevalent wavelengths of light and light intensity, we propose that specific phytochrome-dependent molecular mechanisms are used during light-dependent signaling between the nucleus and chloroplast during photomorphogenesis to coordinate chloroplast development with plant developmental stage and the external environment.

Red-light absorption and fluorescence of phytochrome chromophores: A comparative theoretical study

Energy Technology Data Exchange (ETDEWEB)

Falklöf, Olle; Durbeej, Bo, E-mail: bodur@ifm.liu.se

2013-11-08

Highlights: • Calculation of red-light absorption and emission of phytochrome chromophores. • Comparison of TD-DFT and ab initio methods. • Pure functionals show better accuracy than hybrid functionals. - Abstract: Currently, much experimental effort is being invested in the engineering of phytochromes, a large superfamily of photoreceptor proteins, into fluorescent proteins suitable for bioimaging in the near-infrared regime. In this work, we gain insight into the potential of computational methods to contribute to this development by investigating how well representative quantum chemical methods reproduce recently recorded red-light absorption and emission maxima of synthetic derivatives of the bilin chromophores of phytochromes. Focusing on the performance of time-dependent density functional theory but using also the ab initio CIS(D), CC2 and CASPT2 methods, we explore how various methodological considerations influence computed spectra and find, somewhat surprisingly, that density functionals lacking exact exchange reproduce the experimental measurements with smaller errors than functionals that include exact exchange. Thus, for the important class of chromophores that bilins constitute, the widely established trend that hybrid functionals give more accurate excitation energies than pure functionals does not apply.

Phytochrome B mRNA expression enhances biomass yield and ...

African Journals Online (AJOL)

A wide variety of physiological responses, including most light responses, also are modulated by photoreceptor gene such as PHYB. Phytochrome B (PHYB) expression patterns may be significant in the daily regulation of plant physiology and indicate an unexpectedly intimate relationship between the components of the ...

Nonlinear model-based robust control of a nuclear reactor using adaptive PIF gains and variable structure controller

International Nuclear Information System (INIS)

Park, Moon Ghu; Cho, Nam Zin

1993-01-01

A Nonlinear model-based Hybrid Controller (NHC) is developed which consists of the adaptive proportional-integral-feedforward (PIF) gains and variable structure controller. The controller has the robustness against modeling uncertainty and is applied to the trajectory tracking control of single-input, single-output nonlinear systems. The essence of the scheme is to divide the control into four different terms. Namely, the adaptive P-I-F gains and variable structure controller are used to accomplish the specific control actions by each terms. The robustness of the controller is guaranteed by the feedback of estimated uncertainty and the performance specification given by the adaptation of PIF gains using the second method of Lyapunov. The variable structure controller is incorporated to regulate the initial peak of the tracking error during the parameter adaptation is not settled yet. The newly developed NHC method is applied to the power tracking control of a nuclear reactor and the simulation results show great improvement in tracking performance compared with the conventional model-based control methods. (Author)

Anatomia foliar de microtomateiros fitocromo-mutantes e ultra-estrutura de cloroplastos Leaf anatomy of micro-tomato phytochrome-mutants and chloroplast ultra-structure

Directory of Open Access Journals (Sweden)

Hyrandir Cabral de Melo

2011-02-01

Full Text Available Plantas fitocromo-mutantes têm sido utilizadas com o intuito de caracterizar isoladamente, dentre os demais fotorreceptores, a ação dos fitocromos sobre eventos ligados à fotomorfogênese. Raros são os estudos que relatam a ação dos fitocromos sobre aspectos estruturais, embora sejam fundamentais à compreensão do desenvolvimento das plantas. Neste trabalho, objetivou-se analisar características ultraestruturais de cloroplastos e aspectos anatômicos foliares dos microtomateiros (Solanum lycopersicum L. cv. Micro-Tom fitocromo-mutantes aurea (subexpressa fitocromos, hp1 e atroviolacea (ambos supra-responsivos a eventos mediados por fitocromo em plantas em estágio de floração. Observou-se que os fitocromos são responsáveis pela expressão de muitas características anatômicas da epiderme foliar, assim como do mesofilo e da ultraestrutura dos cloroplastos.Phytochrome-mutant plants have been used for phytochrome action characterization among all photoreceptors, in events of photomorphogenesis. Studies relating the phytochrome action on structural aspects, which are fundamental to the comprehension of plant development, are rare. The objective of this work was to analyze chloroplast ultra structure and leaf anatomical characteristics of micro-tomatos (Solanum lycopersicum L. cv. Micro-Tom phytochrome-mutants aurea (sub express phytochrome, hp1 and atroviolacea (both super express phytochrome events-mediated in plants in the flowering stage. The results show that phytochromes are responsible for the expression of many characteristics of leaf epidermis, mesophyll and chloroplast ultra-structure.

Phytochrome-mediated responses of cells and protoplasts of green calli obtained from the leaves of a CAM plant.

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Mricha, A; Brulfert, J; Pierre, J N; Queiroz, O

1990-04-01

Green callus obtained from leaves of the CAM-inducible plant Kalanchoe blossfeldiana cv. Montezuma has previously been shown to perform C3-type photosynthesis under 16-h days and to shift to crassulacean acid metabolism (CAM) under 9-h days. The utilization of photoperiodic regimes (i.e. night interruptions by 30 min red light) established that CAM induction in the callus was under the control of phytochrome, as shown by measurements of CAM criteria: phosphoenolpyruvate carboxylase activity and malic acid pools. Short-term responsiveness of the callus cells to phytochrome modulations by monochromatic radiations was also established by the rapid changes observed in the diameter of the callus-derived protoplasts. These results provide further evidence that whole plant correlations are not necessary for phytochrome operativity.

Shining a light on the Arabidopsis circadian clock.

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Oakenfull, Rachael J; Davis, Seth J

2017-11-01

The circadian clock provides essential timing information to ensure optimal growth to prevailing external environmental conditions. A major time-setting mechanism (zeitgeber) in clock synchronization is light. Differing light wavelengths, intensities, and photoperiodic duration are processed for the clock-setting mechanism. Many studies on light-input pathways to the clock have focused on Arabidopsis thaliana. Photoreceptors are specific chromic proteins that detect light signals and transmit this information to the central circadian oscillator through a number of different signalling mechanisms. The most well-characterized clock-mediating photoreceptors are cryptochromes and phytochromes, detecting blue, red, and far-red wavelengths of light. Ultraviolet and shaded light are also processed signals to the oscillator. Notably, the clock reciprocally generates rhythms of photoreceptor action leading to so-called gating of light responses. Intermediate proteins, such as Phytochrome interacting factors (PIFs), constitutive photomorphogenic 1 (COP1) and EARLY FLOWERING 3 (ELF3), have been established in signalling pathways downstream of photoreceptor activation. However, the precise details for these signalling mechanisms are not fully established. This review highlights both historical and recent efforts made to understand overall light input to the oscillator, first looking at how each wavelength of light is detected, this is then related to known input mechanisms and their interactions. © 2017 John Wiley & Sons Ltd.

Complete genome sequence of cyanobacterium Nostoc sp. NIES-3756, a potentially useful strain for phytochrome-based bioengineering.

Science.gov (United States)

Hirose, Yuu; Fujisawa, Takatomo; Ohtsubo, Yoshiyuki; Katayama, Mitsunori; Misawa, Naomi; Wakazuki, Sachiko; Shimura, Yohei; Nakamura, Yasukazu; Kawachi, Masanobu; Yoshikawa, Hirofumi; Eki, Toshihiko; Kanesaki, Yu

2016-01-20

To explore the diverse photoreceptors of cyanobacteria, we isolated Nostoc sp. strain NIES-3756 from soil at Mimomi-Park, Chiba, Japan, and determined its complete genome sequence. The Genome consists of one chromosome and two plasmids (total 6,987,571 bp containing no gaps). The NIES-3756 strain carries 7 phytochrome and 12 cyanobacteriochrome genes, which will facilitate the studies of phytochrome-based bioengineering. Copyright © 2015. Published by Elsevier B.V.

PIF1 disruption or NBS1 hypomorphism does not affect chromosome healing or fusion resulting from double-strand breaks near telomeres in murine embryonic stem cells.

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Reynolds, Gloria E; Gao, Qing; Miller, Douglas; Snow, Bryan E; Harrington, Lea A; Murnane, John P

2011-11-10

Telomerase serves to maintain telomeric repeat sequences at the ends of chromosomes. However, telomerase can also add telomeric repeat sequences at DNA double-strand breaks (DSBs), a process called chromosome healing. Here, we employed a method of inducing DSBs near telomeres to query the role of two proteins, PIF1 and NBS1, in chromosome healing in mammalian cells. PIF1 was investigated because the PIF1 homolog in Saccharomyces cerevisiae inhibits chromosome healing, as shown by a 1000-fold increase in chromosome in PIF1-deficient cells. NBS1 was investigated because the functional homolog of NBS1 in S. cerevisiae, Xrs2, is part of the Mre11/Rad50/Xrs2 complex that is required for chromosome healing due to its role in the processing of DSBs and recruitment of telomerase. We found that disruption of mPif1 had no detectable effect on the frequency of chromosome healing at DSBs near telomeres in murine embryonic stem cells. Moreover, the Nbs1(ΔB) hypomorph, which is defective in the processing of DSBs, also had no detectable effect on the frequency of chromosome healing, DNA degradation, or gross chromosome rearrangements (GCRs) that result from telomeric DSBs. Although we cannot rule out small changes in chromosome healing using this system, it is clear from our results that knockout of PIF1 or the Nbs1(ΔB) hypomorph does not result in large differences in chromosome healing in murine cells. These results represent the first genetic assessment of the role of these proteins in chromosome healing in mammals, and suggest that murine cells have evolved mechanisms to ensure the functional redundancy of Pif1 or Nbs1 in the regulation of chromosome healing. Copyright © 2011 Elsevier B.V. All rights reserved.

High-irradiance responses induced by far-red light in grass seedlings of the wild type or overexpressing phytochrome A

International Nuclear Information System (INIS)

Casal, J.J.; Clough, R.C.; Vierstra, R.D.

1996-01-01

The occurrence of phytochrome-mediated high irradiance responses (HIR), previously characterised largely in dicotyledonous plants, was investigated in Triticum aestivum L., Zea mays L., Lolium multiflorum Lam. and in both wild-type Oryza sativa L. and in transgenic plants overexpressing oat phytochrome A under the control of a 35S promoter. Coleoptile growth was promoted (maize, ryegrass) or inhibited (wild-type rice) by continuous far-red light (FRc). However, at equal fluences, hourly pulses of far-red light (FRp) were equally effective, indicating that the growth responses to FRc were not true HIR. In contrast, in maize and rice, FRc increased anthocyanin content in the coleoptile in a fluence-rate dependent manner. This response was a true HIR as FRp had reduced effects. In maize, anthocyanin levels were significantly higher under FRc than under continuous red light. In rice, overexpression of phytochrome A increased the inhibition of coleoptile growth and the levels of anthocyanin under FRc but not under FRp or under continuous red light. The effect of FRc was fluence-rate dependent. In light-grown rice, overexpression of phytochrome A reduced leaf-sheath length, impaired the response to supplementary far-red light, but did not affect the response to canopy shade-light. In grasses, typical HIR, i.e. fluence-rate dependent responses showing reciprocity failure, can be induced by FRc. Under FRc, overexpressed phytochrome A operates through this action mode in transgenic rice. (author)

Overexpression of homologous phytochrome genes in tomato: exploring the limits in photoperception

NARCIS (Netherlands)

Husaineid, S.H.; Kok, R.A.; Schreuder, M.E.L.; Plas, van der L.H.W.; Krol, van der A.R.

2007-01-01

Transgenic tomato [Lycopersicon esculentum (=Solanum lycopersicum)] lines overexpressing tomato PHYA, PHYB1, or PHYB2, under control of the constitutive double-35S promoter from cauliflower mosaic virus (CaMV) have been generated to test the level of saturation in individual phytochrome-signalling

Unique phytochrome responses of the holoparasitic plant Orobanche minor.

Science.gov (United States)

Takagi, Kazuteru; Okazawa, Atsushi; Wada, Yu; Mongkolchaiyaphruek, Anchaya; Fukusaki, Eiichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

2009-06-01

Holoparasitic plants such as Orobanche spp. have lost their photosynthetic ability, so photoresponses to optimize photosynthesis are not necessary in these plants. Photoresponses are also involved in the regulation of plant development but the photoresponses of holoparasites have not been characterized in detail. In this study, the phytochrome (phy)-related photoresponse of Orobanche minor was investigated. Its photoreceptor, phytochrome A (OmphyA), was also characterized. Light effects on germination, shoot elongation, anthocyanin biosynthesis, and OmphyA expression and subcellular localization were analyzed. Red light (R):far-red light (FR) reversible inhibition of O. minor seed germination demonstrated that phy-mediated responses are retained in this holoparasite. Shoot elongation was inhibited by FR but not by R. This pattern is unique among known patterns of plant photoresponses. Additionally, molecular analysis showed that OmphyA is able to respond to the light signals. Interestingly, the unique pattern of photoresponses in O. minor seems to have been modified for adaptation to its parasitic life cycle. We hypothesize that this alteration has resulted from the loss or alteration of some phy-signaling components. Elucidation of altered components in phy signaling in this parasite will provide useful information not only about its physiological characteristics but also about general plant photoreception systems.

Use of phytochrome-dependent reaction in evaluating the effect of space flight factors on the plant organism

Science.gov (United States)

Shteyne, B. A.; Nevzgodina, L. V.; Miller, A. T.

1982-01-01

The effects of space flight factors on lettuce seeds aboard the Kosmos-936 and Kosmos-1129 satellites for 20 days were studied. The phytochrome dependent (PD) reaction of light sensitive seeds was a sensitive criterion for evaluating the biological effects of space flight factors. The PD reaction of air dry lettuce seeds was suppressed after space flight, especially if the seeds were exposed to open space during the flight. Space flight affects the physiological activity of both phytochrome forms, and both the phi sub 730 dependent reactions of lettuce seeds were suppressed.

Analysis of the function of the photoreceptors phytochrome B and phytochrome D in Nicotiana plumbaginifolia and Arabidopsis thaliana.

Science.gov (United States)

Fernández, Aurora Piñas; Gil, Patricia; Valkai, Ildiko; Nagy, Ferenc; Schäfer, Eberhard

2005-05-01

To investigate the mechanism of phytochrome action in vivo, NtPHYB, AtPHYB and phyD:green fluorescent protein (GFP) were overexpressed in Nicotiana plumbaginifolia and Arabidopsis thaliana. The expression of 35S:NtPHYB:GFP and 35S:AtPHYB:GFP complemented the tobacco hgl2 and Arabidopsis phyB-9 mutations, whereas the 35S:AtPHYD:GFP only rescued the hgl2 mutant. All three fusion proteins are transported into the nucleus in all genetic backgrounds. These data indicate that AtPHYD:GFP is biologically active and functions as the main red light receptor in transgenic tobacco, and establish an experimental system for the functional analysis of this elusive photoreceptor in vivo.

A systematic relationship between phytochrome-controlled development and species habitat, for plants grown in simulated natural radiation

International Nuclear Information System (INIS)

Morgan, D.C.; Smith, H.

1979-01-01

A survey of the responsiveness of plant species, typical of open and shade habitats, to simulated natural shade-light quality (i.e. white light plus supplementary far-red) has demonstrated a systematic relationship between habitat and certain developmental responses. Supplementary far-red light has a much greater effect on stem extension rate, petiole length, and leaf dry weight:stem dry weight ratio of the open habitat, shade-intolerant species. Far-red effects on leaf chlorophyll content show no such systematic grading. These results are discussed in relation to habitat adaptation. In most cases, the relationship between developmental response and the estimated phytochrome photoequilibrium, which is established by the radiation treatment, is linear. This is taken as an indication of phytochrome involvement in shade perception. (orig.) [de

Active and silent chromophore isoforms for phytochrome Pr photoisomerization: An alternative evolutionary strategy to optimize photoreaction quantum yields

Directory of Open Access Journals (Sweden)

Yang Yang

2014-01-01

Full Text Available Photoisomerization of a protein bound chromophore is the basis of light sensing of many photoreceptors. We tracked Z-to-E photoisomerization of Cph1 phytochrome chromophore PCB in the Pr form in real-time. Two different phycocyanobilin (PCB ground state geometries with different ring D orientations have been identified. The pre-twisted and hydrogen bonded PCBa geometry exhibits a time constant of 30 ps and a quantum yield of photoproduct formation of 29%, about six times slower and ten times higher than that for the non-hydrogen bonded PCBb geometry. This new mechanism of pre-twisting the chromophore by protein-cofactor interaction optimizes yields of slow photoreactions and provides a scaffold for photoreceptor engineering.

Structural communication between the chromophore-binding pocket and the N-terminal extension in plant phytochrome phyB.

Science.gov (United States)

Velázquez Escobar, Francisco; Buhrke, David; Fernandez Lopez, Maria; Shenkutie, Sintayehu Manaye; von Horsten, Silke; Essen, Lars-Oliver; Hughes, Jon; Hildebrandt, Peter

2017-05-01

The N-terminal extension (NTE) of plant phytochromes has been suggested to play a functional role in signaling photoinduced structural changes. Here, we use resonance Raman spectroscopy to study the effect of the NTE on the chromophore structure of B-type phytochromes from two evolutionarily distant plants. NTE deletion seems to have no effect on the chromophore in the inactive Pr state, but alters the torsion of the C-D ring methine bridge and the surrounding hydrogen bonding network in the physiologically active Pfr state. These changes are accompanied by a shift of the conformational equilibrium between two Pfr substates, which might affect the thermal isomerization rate of the C-D double bond and, thus, account for the effect of the NTE on the dark reversion kinetics. © 2017 Federation of European Biochemical Societies.

Phylogeny of the Celastraceae inferred from phytochrome B gene sequence and morphology.

Science.gov (United States)

Simmons, M P; Clevinger, C C; Savolainen, V; Archer, R H; Mathews, S; Doyle, J J

2001-02-01

Phylogenetic relationships within Celastraceae were inferred using a simultaneous analysis of 61 morphological characters and 1123 base pairs of phytochrome B exon 1 from the nuclear genome. No gaps were inferred, and the gene tree topology suggests that the primers were specific to a single locus that did not duplicate among the lineages sampled. This region of phytochrome B was most useful for examining relationships among closely related genera. Fifty-one species from 38 genera of Celastraceae were sampled. The Celastraceae sensu lato (including Hippocrateaceae) were resolved as a monophyletic group. Loesener's subfamilies and tribes of Celastraceae were not supported. The Hippocrateaceae were resolved as a monophyletic group nested within a paraphyletic Celastraceae sensu stricto. Goupia was resolved as more closely related to Euphorbiaceae, Corynocarpaceae, and Linaceae than to Celastraceae. Plagiopteron (Flacourtiaceae) was resolved as the sister group of Hippocrateoideae. Brexia (Brexiaceae) was resolved as closely related to Elaeodendron and Pleurostylia. Canotia was resolved as the sister group of Acanthothamnus within Celastraceae. Perrottetia and Mortonia were resolved as the sister group of the rest of the Celastraceae. Siphonodon was resolved as a derived member of Celastraceae. Maytenus was resolved as three disparate groups, suggesting that this large genus needs to be recircumscribed.

Phytochrome, plant growth and flowering

Science.gov (United States)

King, R. W.; Bagnall, D. J.

1994-01-01

Attempts to use artificially lit cabinets to grow plants identical to those growing in sunlight have provided compelling evidence of the importance of light quality for plant growth. Changing the balance of red (R) to far-red (FR) radiation, but with a fixed photosynthetic input can shift the phytochrome photoequilibrium in a plant and generate large differences in plant growth. With FR enrichment the plants elongate, and may produce more leaf area and dry matter. Similar morphogenic responses are also obtained when light quality is altered only briefly (15-30 min) at the end-of-the-day. Conversely, for plants grown in natural conditions the response of plant form to selective spectral filtering has again shown that red and far-red wavebands are important as found by Kasperbauer and coworkers. Also, where photosynthetic photon flux densities (PPFD) of sunlight have been held constant, the removal of far-red alone alters plant growth. With FR depletion plants grown in sunlight are small, more branched and darker green. Here we examine the implications for plant growth and flowering when the far-red composition of incident radiation in plant growth chambers is manipulated.

Phytochrome, plant growth and flowering

Energy Technology Data Exchange (ETDEWEB)

King, R.W.; Bagnall, D.J. [CSIRO, Canberra (Australia)

1994-12-31

Attempts to use artificially lit cabinets to grow plants identical to those growing in sunlight have provided compelling evidence of the importance of light quality for plant growth. Changing the balance of red (R) to far-red (FR) radiation, but with a fixed photosynthetic input can shift the phytochrome photoequilibrium in a plant and generate large differences in plant growth. With FR enrichment the plants elongate, and may produce more leaf area and dry matter. Similar morphogenic responses are also obtained when light quality is altered only briefly (15-30 min) at the end-of-the-day. Conversely, for plants grown in natural conditions the response of plant form to selective spectral filtering has again shown that red and far-red wavebands are important as found by Kasperbauer and coworkers. Also, where photosynthetic photon flux densities (PPFD) of sunlight have been held constant, the removal of far-red alone alters plant growth. As shown for chrysanthemum, with FR depletion plants grown in sunlight are small, more branched and darker green. We examine the implications for plant growth and flowering when the far-red composition of incident radiation in plant growth chambers is manipulated.

Differences and similarities in the photoregulation of gibberellin metabolism between rice and dicots.

Science.gov (United States)

Hirose, Fumiaki; Inagaki, Noritoshi; Takano, Makoto

2013-03-01

In rice seedlings, elongation of leaf sheaths is suppressed by light stimuli. The response is mediated by two classes of photoreceptors, phytochromes and cryptochromes. However, it remains unclear how these photoreceptors interact in the process. Our recent study using phytochrome mutants and novel cryptochrome RNAi lines revealed that cryptochromes and phytochromes function cooperatively, but independently to reduce active GA contents in seedlings in visible light. Blue light captured by cryptochrome 1 (cry1a and cry1b) induces robust expression of GA 2-oxidase genes (OsGA2ox4-7). In parallel, phytochrome B with auxiliary action of phytochrome A mediates repression of GA 20-oxidase genes (OsGA20ox2 and OsGA20ox4). The independent effects cumulatively reduce active GA contents, leading to a suppression of leaf sheath elongation. These regulatory mechanisms are distinct from phytochrome B function in dicots. We discuss reasons why the distinct system appeared in rice, and advantages of the rice system in early photomorphogenesis.

Light-grown plants of transgenic tobacco expressing an introduced oat phytochrome A gene under the control of a constitutive viral promoter exhibit persistent growth inhibition by far-red light

International Nuclear Information System (INIS)

McCormac, A.; Whitelam, G.; Smith, H.

1992-01-01

A comparison of the photoregulation of development has been made for etiolated and light-grown plants of wild-type (WT) tobacco (Nicotiana tabacun L.) and an isogenic transgenic line which expresses an introduced oat phytochrome gene (phyA) under the control of a constitutive viral promoter. Etiolated seedlings of both the WT and transgenic line showed irradiance-dependent inhibition of hypocotyl growth under continuous far-red (FR) light; transgenic seedlings showed a greater level of inhibition under a given fluence rate and this is considered to be the result of the heterologous phytochrome protein (PhyA) functioning in a compatible manner with the native etiolated phytochrome. Deetiolation of WT seedlings resulted in a loss of responsiveness to prolonged FR. Light-grown transgenic seedlings, however, continued to respond in an irradiance-dependent manner to prolonged FR and it is proposed that this is a specific function of the constitutive PhyA. Mature green plants of the WT and transgenic lines showed a qualitatively similar growth promotion to a brief end-of-day FR-treatment but this response was abolished in the transgenic plants under prolonged irradiation by this same FR source. Growth inhibition (McCormac et al. 1991, Planta 185, 162-170) and enhanced levels of nitrate-reductase activity under irradiance of low red:far-red ratio, as achieved by the FR-supplementation of white light, emphasised that the introduced PhyA was eliciting an aberrant mode of photoresponse compared with the normal phytochrome population of light-grown plants. Total levels of the oat-encoded phytochrome in the etiolated transgenic tobacco were shown to be influenced by the wavelength of continuous irradiation in a manner which was qualitatively similar to that seen for the native, etiolated tobacco phytochrome, and distinct from that seen in etiolated oat tissues. These results are discussed in terms of the proposal that the constitutive oat-PhyA pool in the transgenic plants

Nuclear Import of the Parsley bZIP Transcription Factor CPRF2 Is Regulated by Phytochrome Photoreceptors

Science.gov (United States)

Kircher, Stefan; Wellmer, Frank; Nick, Peter; Rügner, Alexander; Schäfer, Eberhard; Harter, Klaus

1999-01-01

In plants, light perception by photoreceptors leads to differential expression of an enormous number of genes. An important step for differential gene expression is the regulation of transcription factor activities. To understand these processes in light signal transduction we analyzed the three well-known members of the common plant regulatory factor (CPRF) family from parsley (Petroselinum crispum). Here, we demonstrate that these CPRFs, which belong to the basic- region leucine-zipper (bZIP) domain-containing transcription factors, are differentially distributed within parsley cells, indicating different regulatory functions within the regulatory networks of the plant cell. In particular, we show by cell fractionation and immunolocalization approaches that CPRF2 is transported from the cytosol into the nucleus upon irradiation due to action of phytochrome photoreceptors. Two NH2-terminal domains responsible for cytoplasmic localization of CPRF2 in the dark were characterized by deletion analysis using a set of CPRF2-green fluorescent protein (GFP) gene fusion constructs transiently expressed in parsley protoplasts. We suggest that light-induced nuclear import of CPRF2 is an essential step in phytochrome signal transduction. PMID:9922448

Divergence of the phytochrome gene family predates angiosperm evolution and suggests that Selaginella and Equisetum arose prior to Psilotum.

Science.gov (United States)

Kolukisaoglu, H U; Marx, S; Wiegmann, C; Hanelt, S; Schneider-Poetsch, H A

1995-09-01

Thirty-two partial phytochrome sequences from algae, mosses, ferns, gymnosperms, and angiosperms (11 of them newly released ones from our laboratory) were analyzed by distance and character-state approaches (PHYLIP, TREECON, PAUP). In addition, 12 full-length sequences were analyzed. Despite low bootstrap values at individual internal nodes, the inferred trees (neighbor-joining, Fitch, maximum parsimony) generally showed similar branching orders consistent with other molecular data. Lower plants formed two distinct groups. One basal group consisted of Selaginella, Equisetum, and mosses; the other consisted of a monophyletic cluster of frond-bearing pteridophytes. Psilotum was a member of the latter group and hence perhaps was not, as sometimes suggested, a close relative of the first vascular plants. The results further suggest that phytochrome gene duplication giving rise to a- and b- and later to c-types may have taken place within seedfern genomes. Distance matrices dated the separation of mono- and dicotyledons back to about 260 million years before the present (Myr B.P.) and the separation of Metasequoia and Picea to a fossil record-compatible value of 230 Myr B.P. The Ephedra sequence clustered with the c- or a-type and Metasequoia and Picea sequences clustered with the b-type lineage. The "paleoherb" Nymphaea branched off from the c-type lineage prior to the divergence of mono- and dicotyledons on the a- and b-type branches. Sequences of Piper (another "paleoherb") created problems in that they branched off from different phytochrome lineages at nodes contradicting distance from the inferred trees' origin.

Blue-light mediated accumulation of nuclear-encoded transcripts coding for proteins of the thylakoid membrane is absent in the phytochrome-deficient aurea mutant of tomato

International Nuclear Information System (INIS)

Oelmueller, R.; Kendrick, R.E.; Briggs, W.R.

1989-01-01

Polyclonal antibodies against pea phytochrome detect 2 protein bands (about 116 and 120 kDa) on blots of crude protein extracts and protein of microsomal preparations of dark-grown tomato seedlings. Both protein bands are undetectable in Western blots of the aurea mutant extracts. Neither protein band is detectable after isogenic wild-type seedlings are illuminated with 3 h of red light, either in the crude extract or in the membrane fraction of the irradiated seedlings; this result is consistent with the hypothesis that both bands are phytochrome. When dark-grown wild-type seedlings are illuminated with 3 h of red light or blue light against a red light background, the transcript levels for chlorophyll a/b-binding proteins of photosystem I and II, plastocyanin, and the subunit II of photosystem I increase. In all cases, the same fluence rate of blue light is much more effective than red light alone, a result that indicates the involvement of a blue/UV-A light photoreceptor in addition to the involvement of the far-red-absorbing form of phytochrome, Pfr. The aurea mutant responds neither to red light nor to blue light. Thus, no Pfr-independent induction of the four transcripts by a blue/UV-A light photoreceptor can be measured in the aurea mutant

Bright blue-shifted fluorescent proteins with Cys in the GAF domain engineered from bacterial phytochromes: fluorescence mechanisms and excited-state dynamics

NARCIS (Netherlands)

Hontani, Yusaku; Shcherbakova, Daria M.; Baloban, Mikhail; Zhu, Jingyi; Verkhusha, Vladislav V.; Kennis, John T. M.

2016-01-01

Near-infrared fluorescent proteins (NIR FPs) engineered from bacterial phytochromes (BphPs) are of great interest for in vivo imaging. They utilize biliverdin (BV) as a chromophore, which is a heme degradation product, and therefore they are straightforward to use in mammalian tissues. Here, we

The Crystal Structures of the N-terminal Photosensory Core Module of Agrobacterium Phytochrome Agp1 as Parallel and Anti-parallel Dimers*

Science.gov (United States)

Nagano, Soshichiro; Scheerer, Patrick; Zubow, Kristina; Michael, Norbert; Inomata, Katsuhiko; Lamparter, Tilman; Krauß, Norbert

2016-01-01

Agp1 is a canonical biliverdin-binding bacteriophytochrome from the soil bacterium Agrobacterium fabrum that acts as a light-regulated histidine kinase. Crystal structures of the photosensory core modules (PCMs) of homologous phytochromes have provided a consistent picture of the structural changes that these proteins undergo during photoconversion between the parent red light-absorbing state (Pr) and the far-red light-absorbing state (Pfr). These changes include secondary structure rearrangements in the so-called tongue of the phytochrome-specific (PHY) domain and structural rearrangements within the long α-helix that connects the cGMP-specific phosphodiesterase, adenylyl cyclase, and FhlA (GAF) and the PHY domains. We present the crystal structures of the PCM of Agp1 at 2.70 Å resolution and of a surface-engineered mutant of this PCM at 1.85 Å resolution in the dark-adapted Pr states. Whereas in the mutant structure the dimer subunits are in anti-parallel orientation, the wild-type structure contains parallel subunits. The relative orientations between the PAS-GAF bidomain and the PHY domain are different in the two structures, due to movement involving two hinge regions in the GAF-PHY connecting α-helix and the tongue, indicating pronounced structural flexibility that may give rise to a dynamic Pr state. The resolution of the mutant structure enabled us to detect a sterically strained conformation of the chromophore at ring A that we attribute to the tight interaction with Pro-461 of the conserved PRXSF motif in the tongue. Based on this observation and on data from mutants where residues in the tongue region were replaced by alanine, we discuss the crucial roles of those residues in Pr-to-Pfr photoconversion. PMID:27466363

The Crystal Structures of the N-terminal Photosensory Core Module of Agrobacterium Phytochrome Agp1 as Parallel and Anti-parallel Dimers.

Science.gov (United States)

Nagano, Soshichiro; Scheerer, Patrick; Zubow, Kristina; Michael, Norbert; Inomata, Katsuhiko; Lamparter, Tilman; Krauß, Norbert

2016-09-23

Agp1 is a canonical biliverdin-binding bacteriophytochrome from the soil bacterium Agrobacterium fabrum that acts as a light-regulated histidine kinase. Crystal structures of the photosensory core modules (PCMs) of homologous phytochromes have provided a consistent picture of the structural changes that these proteins undergo during photoconversion between the parent red light-absorbing state (Pr) and the far-red light-absorbing state (Pfr). These changes include secondary structure rearrangements in the so-called tongue of the phytochrome-specific (PHY) domain and structural rearrangements within the long α-helix that connects the cGMP-specific phosphodiesterase, adenylyl cyclase, and FhlA (GAF) and the PHY domains. We present the crystal structures of the PCM of Agp1 at 2.70 Å resolution and of a surface-engineered mutant of this PCM at 1.85 Å resolution in the dark-adapted Pr states. Whereas in the mutant structure the dimer subunits are in anti-parallel orientation, the wild-type structure contains parallel subunits. The relative orientations between the PAS-GAF bidomain and the PHY domain are different in the two structures, due to movement involving two hinge regions in the GAF-PHY connecting α-helix and the tongue, indicating pronounced structural flexibility that may give rise to a dynamic Pr state. The resolution of the mutant structure enabled us to detect a sterically strained conformation of the chromophore at ring A that we attribute to the tight interaction with Pro-461 of the conserved PRXSF motif in the tongue. Based on this observation and on data from mutants where residues in the tongue region were replaced by alanine, we discuss the crucial roles of those residues in Pr-to-Pfr photoconversion. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Phytochrome regulates GTP-binding protein activity in the envelope of pea nuclei

Science.gov (United States)

Clark, G. B.; Memon, A. R.; Thompson, G. A. Jr; Roux, S. J.

1993-01-01

Three GTP-binding proteins with apparent molecular masses of 27, 28 and 30 kDa have been detected in isolated nuclei of etiolated pea plumules. After LDS-PAGE and transfer to nitrocellulose these proteins bind [32P]GTP in the presence of excess ATP, suggesting that they are monomeric G proteins. When nuclei are disrupted, three proteins co-purify with the nuclear envelope fraction and are highly enriched in this fraction. The level of [32P]GTP-binding for all three protein bands is significantly increased when harvested pea plumules are irradiated by red light, and this effect is reversed by far-red light. The results indicate that GTP-binding activity associated with the nuclear envelope of plant cells is photoreversibly regulated by the pigment phytochrome.

Trading direct for indirect defense? Phytochrome B inactivation in tomato attenuates direct anti-herbivore defenses whilst enhancing volatile-mediated attraction of predators

NARCIS (Netherlands)

Cortés, Leandro E.; Weldegergis, Berhane T.; Boccalandro, Hernán E.; Dicke, Marcel; Ballaré, Carlos L.

2016-01-01

Under conditions of competition for light, which lead to the inactivation of the photoreceptor phytochrome B (phyB), the growth of shade-intolerant plants is promoted and the accumulation of direct anti-herbivore defenses is down-regulated. Little is known about the effects of phyB on emissions

Phytochrome B Mediates the Regulation of Chlorophyll Biosynthesis through Transcriptional Regulation of ChlH and GUN4 in Rice Seedlings

Science.gov (United States)

Kagawa, Takatoshi; Tanaka, Ayumi; Ueno, Osamu; Shimada, Hiroaki; Takano, Makoto

2015-01-01

Accurate regulation of chlorophyll synthesis is crucial for chloroplast formation during the greening process in angiosperms. In this study, we examined the role of phytochrome B (phyB) in the regulation of chlorophyll synthesis in rice seedlings (Oryza sativa L.) through the characterization of a pale-green phenotype observed in the phyB mutant grown under continuous red light (Rc) irradiation. Our results show that the Rc-induced chlorophyll accumulation can be divided into two components—a phyB-dependent and a phyB-independent component, and that the pale-green phenotype is caused by the absence of the phyB-dependent component. To elucidate the role of the missing component we established an Rc-induced greening experiment, the results of which revealed that several genes encoding proteins on the chlorophyll branch were repressed in the phyB mutant. Notable among them were ChlH and GUN4 genes, which encode subunit H and an activating factor of magnesium chelatase (Mg-chelatase), respectively, that were largely repressed in the mutant. Moreover, the kinetic profiles of chlorophyll precursors suggested that Mg-chelatase activity simultaneously decreased with the reduction in the transcript levels of ChlH and GUN4. These results suggest that phyB mediates the regulation of chlorophyll synthesis through transcriptional regulation of these two genes, whose products exert their action at the branching point of the chlorophyll biosynthesis pathway. Reduction of 5-aminolevulinic acid (5-ALA) synthesis could be detected in the mutant, but the kinetic profiles of chlorophyll precursors indicated that it was an event posterior to the reduction of the Mg-chelatase activity. It means that the repression of 5-ALA synthesis should not be a triggering event for the appearance of the pale-green phenotype. Instead, the repression of 5-ALA synthesis might be important for the subsequent stabilization of the pale-green phenotype for preventing excessive accumulation of hazardous

Ultraviolet light inhibition of phytochrome-induced flavonoid biosynthesis and DNA photolyase formation in mustard cotyledons (Sinapis alba L.)

International Nuclear Information System (INIS)

Buchholz, G.; Ehmann, B.; Wellmann, E.

1995-01-01

In cotyledons of etiolated mustard (Sinapis alba L.) seedlings, phytochrome-far-red-absorbing form-induced flavonoid biosynthesis was found to be inhibited by short-term ultraviolet (UV) irradiations. UV inhibition was shown for the synthesis of quercetin, anthocyanin, and also for the accumulation of the mRNA for chalcone synthase, the key enzyme of this pathway. The UV effect was more pronounced on flavonoid biosynthesis, a process that selectively occurs in the epidermal layers, than on the synthesis of mRNA for chlorophyll a/b-binding protein localized in the mesophyll tissue. These UV inhibitory effects were accompanied by cyclobutane pyrimidine dimer (CPD) formation showing a linear fluence-response relationship. CPD formation and UV inhibition of flavonoid biosynthesis was found to be partially reversible by blue/UV-A light via DNA photolyase (PRE), allowing photoreactivation of the DNA by splitting of CPDs, which are the cause of the UV effect. Like flavonoid formation PRE was also induced by the far-red-absorbing form of phytochrome and induction was inhibited by UV. A potential risk of inhibition, in response to solar UV-B irradiation, was shown for anthocyanin formation. This inhibition, however, occurred only if photoreactivation was experimentally reduced. The PRE activity present in the etiolated seedlings (further increasing about 5-fold during light acclimatization) appears to be sufficient to prevent the persistence of CPDs even under conditions of high solar irradiation

Photomorphogenesis in Sinningia speciosa, cv. Queen Victoria I. Characterization of Phytochrome Control.

Science.gov (United States)

Satter, R L; Wetherell, D F

1968-06-01

The morphological development of Sinningia speciosa plants that were exposed to supplementary far red light was very different from that of plants receiving dark nights. After several nights of such irradiation, stems and petioles were elongated, petioles were angulated, leaf blade expansion was inhibited, plants were chlorotic and the accumulation of shoot dry weight was retarded.Red reversibility of the morphological changes potentiated by far red light indicated control by the phytochrome system. A high P(FR) level during the last half of the night inhibited stem elongation and promoted leaf blade expansion, but both of these processes were hardly affected by the P(FR) level during the first half of the night. Thus sensitivity to P(FR) was cyclic.The interpretation of our experiments was complicated by quantitative morphological differences resulting from long, as compared to short, far red irradiations.

Characterization and Diversity of Novel PIF/Harbinger DNA Transposons in Brassica Genomes

International Nuclear Information System (INIS)

Nouroz, F.; Noreen, S.; Harrison, H.

2016-01-01

Among DNA transposons, PIF/Harbinger is most recently identified superfamily characterized by 3 bp target site duplications (TSDs), flanked by 14-45 bp terminal inverted repeats (TIRs) and displaying DDD or DDE domain displaying transposase. Their autonomous elements contain two open reading frames, ORF1 and ORF2 encoding superfamily specific transposase and DNA-binding domain. Harbinger DNA transposons are recently identified in few plants. In present study, computational and molecular approaches were used for the identification of 8 Harbinger transposons, of which only 2 were complete with putative trans posase, while rest 6 lack transposase and are considered as defective or non-autonomous elements. They ranged in size from 0.5-4 kb with 3 bp TSDs, 15-42 bp TIRs and internal AT richregions. The PCR amplification of Brassica Harbinger transposase revealed diversity and ancient nature of these elements. The amplification polymorphism of some non-autonomous Harbingers showed species specific distribution. Phylogenetic analyses of transposase clustered them into two clades (monocot and dicot) and five sub-clades. The Brassica, Arabidopsis and Malustransposase clustered into genera specific sub-clades; although a lot of homology in transposase was observed. The multiple sequence alignment of Brassica and related transposase showed homology in five conserved blocks. The DD/Sub 35/E triad and sequences showed similarity to already known Pong-like or Arabidopsis ATIS12 Harbinger transposase in contrast to other transposase having DD/Sub 47/E or DD/Sub 48/E motifs. The present study will be helpful in the characterization of Harbingers, their structural diversity in related genera and Harbinger based molecular markers for varietal/lines identifications. (author)

Chloroacetaldehyde-induced mutagenesis in Escherichia coli: The role of AlkB protein in repair of 3,N4-ethenocytosine and 3,N4-α-hydroxyethanocytosine

International Nuclear Information System (INIS)

Maciejewska, Agnieszka M.; Ruszel, Karol P.; Nieminuszczy, Jadwiga; Lewicka, Joanna; Sokolowska, Beata; Grzesiuk, Elzbieta; Kusmierek, Jaroslaw T.

2010-01-01

Etheno (ε) adducts are formed in reaction of DNA bases with various environmental carcinogens and endogenously created products of lipid peroxidation. Chloroacetaldehyde (CAA), a metabolite of carcinogen vinyl chloride, is routinely used to generate ε-adducts. We studied the role of AlkB, along with AlkA and Mug proteins, all engaged in repair of ε-adducts, in CAA-induced mutagenesis. The test system used involved pIF102 and pIF104 plasmids bearing the lactose operon of CC102 or CC104 origin (Cupples and Miller (1989) ) which allowed to monitor Lac + revertants, the latter arose by GC → AT or GC → TA substitutions, respectively, as a result of modification of guanine and cytosine. The plasmids were CAA-damaged in vitro and replicated in Escherichia coli of various genetic backgrounds. To modify the levels of AlkA and AlkB proteins, mutagenesis was studied in E. coli cells induced or not in adaptive response. Formation of εC proceeds via a relatively stable intermediate, 3,N 4 -α-hydroxyethanocytosine (HEC), which allowed to compare repair of both adducts. The results indicate that all three genes, alkA, alkB and mug, are engaged in alleviation of CAA-induced mutagenesis. The frequency of mutation was higher in AlkA-, AlkB- and Mug-deficient strains in comparison to alkA + , alkB + , and mug + controls. Considering the levels of CAA-induced Lac + revertants in strains harboring the pIF plasmids and induced or not in adaptive response, we conclude that AlkB protein is engaged in the repair of εC and HEC in vivo. Using the modified TTCTT 5-mers as substrates, we confirmed in vitro that AlkB protein repairs εC and HEC although far less efficiently than the reference adduct 3-methylcytosine. The pH optimum for repair of HEC and εC is significantly different from that for 3-methylcytosine. We propose that the protonated form of adduct interact in active site of AlkB protein.

Yeast Sub1 and human PC4 are G-quadruplex binding proteins that suppress genome instability at co-transcriptionally formed G4 DNA.

Science.gov (United States)

Lopez, Christopher R; Singh, Shivani; Hambarde, Shashank; Griffin, Wezley C; Gao, Jun; Chib, Shubeena; Yu, Yang; Ira, Grzegorz; Raney, Kevin D; Kim, Nayun

2017-06-02

G-quadruplex or G4 DNA is a non-B secondary DNA structure consisting of a stacked array of guanine-quartets that can disrupt critical cellular functions such as replication and transcription. When sequences that can adopt Non-B structures including G4 DNA are located within actively transcribed genes, the reshaping of DNA topology necessary for transcription process stimulates secondary structure-formation thereby amplifying the potential for genome instability. Using a reporter assay designed to study G4-induced recombination in the context of an actively transcribed locus in Saccharomyces cerevisiae, we tested whether co-transcriptional activator Sub1, recently identified as a G4-binding factor, contributes to genome maintenance at G4-forming sequences. Our data indicate that, upon Sub1-disruption, genome instability linked to co-transcriptionally formed G4 DNA in Top1-deficient cells is significantly augmented and that its highly conserved DNA binding domain or the human homolog PC4 is sufficient to suppress G4-associated genome instability. We also show that Sub1 interacts specifically with co-transcriptionally formed G4 DNA in vivo and that yeast cells become highly sensitivity to G4-stabilizing chemical ligands by the loss of Sub1. Finally, we demonstrate the physical and genetic interaction of Sub1 with the G4-resolving helicase Pif1, suggesting a possible mechanism by which Sub1 suppresses instability at G4 DNA. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

RNF4 interacts with multiSUMOylated ETV4.

Science.gov (United States)

Aguilar-Martinez, Elisa; Guo, Baoqiang; Sharrocks, Andrew D

2016-01-01

Protein SUMOylation represents an important regulatory event that changes the activities of numerous proteins. Recent evidence demonstrates that polySUMO chains can act as a trigger to direct the ubiquitin ligase RNF4 to substrates to cause their turnover through the ubiquitin pathway. RNF4 uses multiple SUMO interaction motifs (SIMs) to bind to these chains. However, in addition to polySUMO chains, a multimeric binding surface created by the simultaneous SUMOylation of multiple residues on a protein or complex could also provide a platform for the recruitment of multi-SIM proteins like RNF4. Here we demonstrate that multiSUMOylated ETV4 can bind to RNF4 and that a unique combination of SIMs is required for RNF4 to interact with this multiSUMOylated platform. Thus RNF4 can bind to proteins that are either polySUMOylated through a single site or multiSUMOylated on several sites and raises the possibility that such multiSIM-multiSUMO interactions might be more widespread.

[Drug interactions in chronic prescription].

Science.gov (United States)

Comet, D; Casajuana, J; Bordas, J M; Fuentes, M A; Arnáiz, J A; Núñez, B; Pou, R

1997-06-30

Application of computerized program for detection of potential drug interactions (PDI) in chronic prescriptions in four primary care centers. To evaluate the clinical significance of PDI identified according to clinical criterions. An observational crossover study. Clutat Vella health district (City of Barcelona). Using information of Consejo General de Colegios Oficiales de Farmaceuticos databases and the chronic prescriptions database of the primary care centers, computerized drug-interaction system have been developed for detection of PDI in patients. A panel of primary care physicians and clinical pharmacists developed criteria that were used to evaluate the clinical significance of PDI. 9840 Cards of Authorized Prescription (CAP) were analyzed, 36108 medicaments and 42877 drugs. A total of 2140 patients were involved for a total of 3406 PDI, 21.75% of patients with CAP. Clinical signification for the panel was found in 40.07% of these 3406 PIF; 3.78% were suggest to avoid the association drugs. The incidence of PDI with clinical signification are lower than other studies of the literature; it suggest a appropriate knowledge of drug prescription. The application of computerized program make much more easy the detection of adverse drug interactions in chronic prescription.

Phytochrome control of gene expression in radish seedlings. 111. Evidence for a rapid control of the ribulose 1. 5 biphosphate carboxylase small subunit gene expression by red light

Energy Technology Data Exchange (ETDEWEB)

Fourcroy, P

1986-01-01

The effect of red and far-red light on the level of the mRNA encoding the small subunit (SSU) of ribulose, 1.5 bisphosphate carboxylase (RuBisCO; EC 4.1.1.39) from radish cotyledons was investigated. Northern blot analysis of RNA with a cDNA probe showed that both long (12-36h) far-red irradiation and short (1-5 min) red irradiation brings about an increase in SSU mRNA concentraton which was prevented by a subsequent far-red light exposure. Far-red light was effective in reversing the red light effect provided that it was given soon after (<10 min) the red light pulse. The red light mediated increase in SSU mRNA level did not occur in presence of ..cap alpha..-amanitin. Our results suggest that phytochrome control of SSU gene expression is exerted at the transcriptional level. 34 refs.

Nicotiana plumbaginifolia hlg mutants have a mutation in a PHYB-type phytochrome gene: they have elongated hypocotyls in red light, but are not elongated as adult plants.

Science.gov (United States)

Hudson, M; Robson, P R; Kraepiel, Y; Caboche, M; Smith, H

1997-11-01

Two new allelic mutants of Nicotiana plumbaginifolia have been isolated which display a hypocotyl which is long (hlg) when seedlings are grown in continuous white light (W). This can be accounted for by the decreased response to red light (R) of the hypocotyl elongation rate in these mutants. Responses to other wavelengths are unaffected in the mutants. When grown in white light, mature hlg mutants are not elongated with respect to the wild-type; they also bolt and flower later. The shade-avoidance responses to red/far red ratio (R:FR) are intact in these mutants. Both mutants are deficient in phyB-like polypeptide that is immunodetectable in the wild-type; both have wild-type levels of a phyA-like polypeptide. These alleles are inherited in a partially dominant manner, and correspond to single-base missense mutations in a gene highly homologous to N. tabacum PHYB, which codes for a phytochrome B-type photoreceptor. One allele, hlg-1, has an introduced amino acid substitution; this may define a residue essential for phytochrome protein stability. The other allele, hlg-2, has a stop codon introduced C-terminal to the chromophore binding domain. As these phyB mutants are unaffected in shade-avoidance responses, but deficient in perception of R, it is concluded that the phyB absent in these mutants is responsible for R perception in the N. plumbaginifolia seedling, but is not a R:FR sensor in light-grown plants.

Specific interaction of CXCR4 with CD4 and CD8α: Functional analysis of the CD4/CXCR4 interaction in the context of HIV-1 envelope glycoprotein-mediated membrane fusion

International Nuclear Information System (INIS)

Basmaciogullari, Stephane; Pacheco, Beatriz; Bour, Stephan; Sodroski, Joseph

2006-01-01

We investigated possible interactions between HIV-1 receptor (CD4) and the main coreceptors CXCR4 and CCR5. We found that CD4 and CXCR4 coexpressed in 293T cells form a complex that can be immunoprecipitated with antibodies directed against the extracellular domain of either protein. Mutagenesis revealed that the CD4/CXCR4 interaction maps to two previously uncharacterized basic motifs in the cytoplasmic domain of CD4. HIV-1 envelope glycoprotein-mediated membrane fusion was found to be independent of the ability of CD4 and CXCR4 to interact, whether fusion was studied in a virus-cell or a cell-cell model. However, this interaction might explain the adaptation of HIV-1 to CXCR4 as an alternative to CCR5. We found that CXCR4 also interacts with the cytoplasmic domain of CD8α in a way that is similar to the CD4/CXCR4 interaction. The CD4/CXCR4 and CD8α/CXCR4 interactions may thus be involved in cellular signaling pathways shared by the CD4 and CD8α molecules

A single haplotype hyposensitive to light and requiring strong vernalization dominates Arabidopsis thaliana populations in Patagonia, Argentina.

Science.gov (United States)

Kasulin, Luciana; Rowan, Beth A; León, Rolando J C; Schuenemann, Verena J; Weigel, Detlef; Botto, Javier F

2017-07-01

The growing collection of sequenced or genotyped Arabidopsis thaliana accessions includes mostly individuals from the native Eurasian and N. African range and introduced North American populations. Here, we describe the genetic and phenotypic diversity, along with habitats and life history, of A. thaliana plants collected at the southernmost end of its worldwide distribution. Seed samples were harvested from plants growing in four sites within a ~3500-km 2 -area in Patagonia, Argentina, and represent the first germplasm to be collected in South America for this species. Whole-genome resequencing revealed that plants from the four sites and a Patagonia herbarium specimen collected in 1967 formed a single haplogroup (Pat), indicating that the phenotypic variation observed in the field reflected plastic responses to the environment. admixture and principal components analyses suggest that the ancestor of the Pat haplogroup either came from Italy or the Balkan/Caucasus regions of Eurasia. In the laboratory, plants from the Pat haplogroup were hyposensitive to continuous red (Rc) and shade light, with corresponding changes in the expression of phytochrome signalling genes. Pat had higher PIF3 and PIF5 and lower HY5 expression under Rc light; and lower expression of PIL1, ATHB2 and HFR1 under shade compared to Col-0. In addition, Pat plants had a strong vernalization requirement associated with high levels of FLC expression. We conclude that including Pat in studies of natural variation and in comparison with other introduced populations will provide additional information for association studies and allow for a more detailed assessment of the demographic events following colonization. © 2017 John Wiley & Sons Ltd.

Maintaining the U.S. Army Research, Development and Engineering Command Prototype Integration Facilities

Science.gov (United States)

2014-05-01

shelters, tents and fabric covers, mechanical aerial delivery parts and components, kitchens , and combat feeding items (see Figure 4). NSRDEC’s PIF is...generic terms and refrain from revealing confidential or classified information. Research hypotheses are as follows: H1: The PIF leadership predicts

Autonomic hyper-vigilance in post-infective fatigue syndrome.

Science.gov (United States)

Kadota, Yumiko; Cooper, Gavin; Burton, Alexander R; Lemon, Jim; Schall, Ulrich; Lloyd, Andrew; Vollmer-Conna, Ute

2010-09-01

This study examined whether post-infective fatigue syndrome (PIFS) is associated with a disturbance in bidirectional autonomic signalling resulting in heightened perception of symptoms and sensations from the body in conjunction with autonomic hyper-reactivity to perceived challenges. We studied 23 patients with PIFS and 25 healthy matched control subjects. A heartbeat discrimination task and a pressure pain threshold test were used to assess interoceptive sensitivity. Cardiac response was assessed over a 4-min Stroop task. PIFS was associated with higher accuracy in heartbeat discrimination and a lower pressure pain threshold. Increased interoceptive sensitivity correlated strongly with current symptoms and potentiated differences in the cardiac response to the Stroop task, which in PIFS was characterized by insensitivity to task difficulty and lack of habituation. Our results provide the first evidence of heightened interoceptive sensitivity in PIFS. Together with the distinct pattern in cardiac responsivity these findings present a picture of physiological hyper-vigilance and response inflexibility. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Isolation and characterization of a cDNA encoding phytochrome A in the non-photosynthetic parasitic plant, Orobanche minor Sm.

Science.gov (United States)

Trakulnaleamsai, Chitra; Okazawa, Atsushi; An, Chung-Il; Kajiyama, Shin'ichiro; Fukusaki, Ei'ichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

2005-01-01

In this study, the isolation and characterization of a phytochrome A (PHYA) homologous cDNA (OmPHYA) in the non-photosynthetic holoparasitic plant Orobanche minor are described. The present findings provide the first report of the presence of a PHYA homolog in the holoparasite. This study found that OmPHYA is of similar size to the other PHYAs of green plants and shows 72, 77, and 77% amino acid sequence identity with PHYA in Arabidopsis, potato, and tobacco respectively. The OmPHYA contains a conserved chromophore attachment cysteine at position 323. Although OmPHYA shows high sequence identity with other PHYAs in green plants, 13 amino acid substitutions located in both the N and C-terminal domains are observed (a total of 26 amino acids). OmPHYA is encoded by a single gene within the O. minor genome. The abundance of the OmPHYA transcript as well as nuclear translocation of OmphyA occurs in a light-dependent manner.

In response to partial plant shading, the lack of phytochrome A does not directly induce leaf senescence but alters the fine-tuning of chlorophyll biosynthesis

Science.gov (United States)

Brouwer, Bastiaan; Gardeström, Per; Keech, Olivier

2014-01-01

Phytochrome is thought to control the induction of leaf senescence directly, however, the signalling and molecular mechanisms remain unclear. In the present study, an ecophysiological approach was used to establish a functional connection between phytochrome signalling and the physiological processes underlying the induction of leaf senescence in response to shade. With shade it is important to distinguish between complete and partial shading, during which either the whole or only a part of the plant is shaded, respectively. It is first shown here that, while PHYB is required to maintain chlorophyll content in a completely shaded plant, only PHYA is involved in maintaining the leaf chlorophyll content in response to partial plant shading. Second, it is shown that leaf yellowing associated with strong partial shading in phyA-mutant plants actually correlates to a decreased biosynthesis of chlorophyll rather than to an increase of its degradation. Third, it is shown that the physiological impact of this decreased biosynthesis of chlorophyll in strongly shaded phyA-mutant leaves is accompanied by a decreased capacity to adjust the Light Compensation Point. However, the increased leaf yellowing in phyA-mutant plants is not accompanied by an increase of senescence-specific molecular markers, which argues against a direct role of PHYA in inducing leaf senescence in response to partial shade. In conclusion, it is proposed that PHYA, but not PHYB, is essential for fine-tuning the chlorophyll biosynthetic pathway in response to partial shading. In turn, this mechanism allows the shaded leaf to adjust its photosynthetic machinery to very low irradiances, thus maintaining a positive carbon balance and repressing the induction of leaf senescence, which can occur under prolonged periods of shade. PMID:24604733

Selection of the important performance influencing factors for the assessment of human error under accident management situations in nuclear power plants

International Nuclear Information System (INIS)

Kim, J. H.; Jung, W. J.

1999-01-01

This paper introduces the process and final results of selection of the important Performance Influencing Factors (PIFs) under emergency operation and accident management situations in nuclear power plants for use in the assessment of human errors. We collected two types of PIF taxonomies, one is the full set PIF list mainly developed for human error analysis, and the other is the PIFs for human reliability analysis (HRA) in probabilistic safety assessment (PSA). 5 PIF taxonomies among the full set PIF list and 10 PIF taxonomies among HRA methodologies (CREAM, SLIM, INTENT, were collected in this research. By reviewing and analyzing PIFs selected for HRA methodologies, the criterion could be established for the selection of appropriate PIFs under emergency operation and accident management situations. Based on this selection criteria, a new PIF taxonomy was proposed for the assessment of human error under emergency operation and accident management situations in nuclear power plants

Evaluation of spatial pressure distribution during ice-structure interaction using pressure indicating film

Directory of Open Access Journals (Sweden)

Kim Hyunwook

2014-09-01

Full Text Available Understanding of ‘spatial’ pressure distribution is required to determine design loads on local structures, such as plating and framing. However, obtaining a practical ‘spatial’ pressure distribution is a hard task due to the sensitivity of the data acquisition frequency and resolution. High-resolution Pessure-Idicating Flm (PIF was applied to obtain pressure distribution and pressure magnitude using stepped crushing method. Different types of PIF were stacked at each test to creating a pressure distribution plot at specific time steps. Two different concepts of plotting ‘spatial’ pressure-area curve was introduced and evaluated. Diverse unit pixel size was chosen to investigate the effect of the resolution in data analysis. Activated area was not significantly affected by unit pixel size; however, total force was highly sensitive

Pelvic Insufficiency Fracture After Pelvic Radiotherapy for Cervical Cancer: Analysis of Risk Factors

International Nuclear Information System (INIS)

Oh, Dongryul; Huh, Seung Jae; Nam, Heerim; Park, Won; Han, Youngyih; Lim, Do Hoon; Ahn, Yong Chan; Lee, Jeong Won; Kim, Byoung Gie; Bae, Duk Soo; Lee, Je Ho

2008-01-01

Purpose: To investigate the incidence, clinical characteristics, and risk factors of pelvic insufficiency fracture (PIF) after pelvic radiotherapy (RT) in cervical cancer. Methods and Materials: Medical records and imaging studies, including bone scintigraphy, CT, and MRI of 557 patients with cervical cancer who received whole-pelvic RT between January 1998 and August 2005 were reviewed. Results: Eighty-three patients were diagnosed as having PIF after pelvic RT. The 5-year cumulative incidence of PIF was 19.7%. The most commonly involved site was the sacroiliac joint. Pelvic pain developed in 48 patients (57.8%) at diagnosis. Eleven patients (13.3%) needed admission or narcotics because of severe pain, and others had good relief of symptoms with conservative management. In univariate analysis, age ≥55 years (p < 0.001), anteroposterior/posteroanterior parallel opposing technique (p = 0.001), curative treatment (p < 0.001), and radiation dose ≥50.4 Gy (p = 0.005) were the predisposing factors for development of PIF. Concurrent chemotherapy (p = 0.78) was not significant. Multivariate analysis showed that age ≥55 years (p < 0.001), body weight <55 kg (p = 0.02), curative treatment (p = 0.03), and radiation dose ≥50.4 Gy (p = 0.04) were significant predisposing factors for development of PIF. Conclusion: The development of PIF is not rare after pelvic RT. The use of multibeam arrangements to reduce the volume and dose of irradiated pelvic bone can be helpful to minimize the risk of fracture, especially in elderly women with low body weight

Development of a taxonomy of performance influencing factors for human reliability assessment of accident management tasks and its application

International Nuclear Information System (INIS)

Kim, Jae Whan; Jung, Won Dae; Kang, Dae Il; Ha, Jae Joo

1999-06-01

In this study, a new PIF taxonomy for HRA of the tasks during emergency operation and accident management situations. We collected the existing PIF taxonomies as many as possible. Then, we analyzed the trend in the selection of PIFs, the frequency of use between PIFs in HRA methods, and the level of definition of PIFs, in order to reflect these characteristics into the development of a new PIF taxonomy. Next, we analyzed the principal task context during accident management to draw the context specific PIFs. Afterwards, we established several criteria for the selection of the appropriate PIFs for HRA under emergency operation and accident management situations. Finally, the final PIF taxonomy containing the subitems for assessing each PIF was constructed based on the results of the previous steps and the selection criteria. The final result of this study is the new PIF taxonomy for HRA of the tasks during emergency operation and accident management situations. The selected 11 PIFs in the study are as follows: training and experience, availability and quality of information, status and trend of critical parameters, status of safety system/component, time pressure, working environment features, team cooperation and communication, plant policy and safety culture. (author). 35 refs., 23 tabs

Development of a taxonomy of performance influencing factors for human reliability assessment of accident management tasks and its application

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Whan; Jung, Won Dae; Kang, Dae Il; Ha, Jae Joo

1999-06-01

In this study, a new PIF taxonomy for HRA of the tasks during emergency operation and accident management situations. We collected the existing PIF taxonomies as many as possible. Then, we analyzed the trend in the selection of PIFs, the frequency of use between PIFs in HRA methods, and the level of definition of PIFs, in order to reflect these characteristics into the development of a new PIF taxonomy. Next, we analyzed the principal task context during accident management to draw the context specific PIFs. Afterwards, we established several criteria for the selection of the appropriate PIFs for HRA under emergency operation and accident management situations. Finally, the final PIF taxonomy containing the subitems for assessing each PIF was constructed based on the results of the previous steps and the selection criteria. The final result ofthis study is the new PIF taxonomy for HRA of the tasks during emergency operation and accident management situations. The selected 11 PIFs in the study are as follows: training and experience, availability and quality of information, status and trend of critical parameters, status of safety system/component, time pressure, working environment features, team cooperation and communication, plant policy and safety culture. (author). 35 refs., 23 tabs.

Phytochrome controls achene germination in Bidens pilosa L. (Asteraceae by very low fluence response

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Adriana Amaral-Baroli

2001-06-01

Full Text Available Achene without ornament of the tegument were light insensitive with germination under all tested light conditions. Achene with verrucose ornament of the tegument presented low germination under darkness and high germination under light conditions. By pre-incubation at 36° C for remotion of pre-existing Pfr and by comparison of results of counting of dark germinating achenes at the end of experiment and daily under dim green safe light (0.001mumol m-2 s-1 nm-1 we concluded that germination was controlled by phytochrome through very low fluence response.Aquênios sem ornamento do tegumento são insensíveis à luz com ocorrência de germinação sob todas as condições de luz testadas. Aquênios com ornamento verrucoso do tegumento apresentou baixa germinação sob escuro e alta germinação sob luz. A pré-incubação a 36° C para a remoção de Fve pré-existente e pela comparação dos resultados de contagem no final do experimento de aquênios que germinam no escuro e diárias sob luz verde de segurança (0.001mimol m-2s-1nm-1 concluimos que a germinação de Bidens pilosa é controlada pelo fitocromo através da resposta de fluência baixa.

Phylogeny of the Celastraceae inferred from 26S nuclear ribosomal DNA, phytochrome B, rbcL, atpB, and morphology.

Science.gov (United States)

Simmons, M P; Savolainen, V; Clevinger, C C; Archer, R H; Davis, J I

2001-06-01

Phylogenetic relationships within Celastraceae (spindle-tree family) were inferred from nucleotide sequence characters from the 5' end of 26S nuclear ribosomal DNA (including expansion segments D1-D3; 84 species sampled), phytochrome B (58 species), rbcL (31 species), atpB (23 species), and morphology (94 species). Among taxa of questionable affinity, Forsellesia is a member of Crossosomataceae, and Goupia is excluded from Celastraceae. However, Brexia, Canotia, Lepuropetalon, Parnassia, Siphonodon, and Stackhousiaceae are supported as members of Celastraceae. Gymnosporia and Tricerma are distinct from Maytenus, Cassine is supported as distinct from Elaeodendron, and Dicarpellum is distinct from Salacia. Catha, Maytenus, and Pristimera are not resolved as natural genera. Hippocrateaceae (including Plagiopteron and Lophopetalum) are a clade nested within a paraphyletic Celastraceae. These data also suggest that the Loesener's classification of Celastraceae sensu stricto and Hallé's classification of Hippocrateaceae are artificial. The diversification of the fruit and aril within Celastraceae appears to be complex, with multiple origins of most fruit and aril forms. Copyright 2001 Academic Press.

Pelvic insufficiency fractures in postmenopausal woman with advanced cervical cancer treated by radiotherapy

International Nuclear Information System (INIS)

Ogino, Ichiro; Okamoto, Naoyuki; Ono, Yoshimi; Kitamura, Tatsuo; Nakayama, Hiroki

2003-01-01

Purpose: To assess the predisposing factors and clinical characteristics of pelvic insufficiency fractures (PIF) in postmenopausal women with pelvic irradiation. Material and methods: A total 335 postmenopausal patients with cervical cancer of the intact uterus treated with radiation therapy between 1983 and 1998 were reviewed. Total external dose was delivered between 45 and 50.4 Gy with parallel opposed anteroposterior portals. Total brachytherapy dose at point A was delivered between 10 and 36 Gy. PIF were diagnosed by bone scintigraphy and confirmed by computed tomography. The cumulative incidence of symptomatic PIF was estimated by actuarial methods. Potential risk factors (age, weight, type II diabetes, delivery, menopause, total external dose, total brachytherapy dose) were assessed. Results: Fifty-seven (17.0%) of 335 patients were diagnosed as having PIF. Forty-seven patients were symptomatic and ten were asymptomatic. Parameters carrying a significant association with PIF were body weight 49 kg or below (P=0.044) in stepwise logistic regression analysis. The cumulative incidence of symptomatic PIF at 5 years was 17.9% calculated by the Kaplan-Meier method. A body weight of 49 kg or below and more than three deliveries were identified as having a significant effect on symptomatic PIF in univariate analysis (P=0.021, P=0.003, log-rank test) and Cox life table regression analysis (P=0.038, P=0.013). Five patients required narcotic agents and eight patients required hospital admission. Conclusions: We should consider reducing the dose contribution to the sacrum and sacroilac joints, without underdosing the tumor, especially in postmenopausal women with many deliveries or low body weight

Brassinosteroid biosynthesis is modulated via a transcription factor cascade of COG1, PIF4, and PIF5

Czech Academy of Sciences Publication Activity Database

Wei, Z.; Yuan, T.; Tarkowská, Danuše; Kim, J.; Nam, H. G.; Novák, Ondřej; He, K.; Gou, X.; Li, J.

2017-01-01

Roč. 174, č. 2 (2017), s. 1260-1273 ISSN 0032-0889 R&D Projects: GA MŠk LK21306; GA ČR GA14-34792S Institutional support: RVO:61389030 Keywords : GSK3-LIKE KINASE BIN2 * ARABIDOPSIS-THALIANA * CATHARANTHUS-ROSEUS Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 6.456, year: 2016

RNF4 interacts with multiSUMOylated ETV4 [version 2; referees: 2 approved

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Elisa Aguilar-Martinez

2017-02-01

Full Text Available Protein SUMOylation represents an important regulatory event that changes the activities of numerous proteins. Recent evidence demonstrates that polySUMO chains can act as a trigger to direct the ubiquitin ligase RNF4 to substrates to cause their turnover through the ubiquitin pathway. RNF4 uses multiple SUMO interaction motifs (SIMs to bind to these chains. However, in addition to polySUMO chains, a multimeric binding surface created by the simultaneous SUMOylation of multiple residues on a protein or complex could also provide a platform for the recruitment of multi-SIM proteins like RNF4. Here we demonstrate that multiSUMOylated ETV4 can bind to RNF4 and that a unique combination of SIMs is required for RNF4 to interact with this multiSUMOylated platform. Thus RNF4 can bind to proteins that are either polySUMOylated through a single site or multiSUMOylated on several sites and raises the possibility that such multiSIM-multiSUMO interactions might be more widespread.

Regulation of the subunit composition of plastidic glutamine synthetase of the wild-type and of the phytochrome-deficient aurea mutant of tomato by blue/UV-A- or by UV-B-light

International Nuclear Information System (INIS)

Migge, A.; Carrayol, E.; Hirel, B.; Lohmann, M.; Meya, G.; Becker, T.W.

1998-01-01

The photomorphogenetic aurea mutant of tomato severely deficient in spectrophotometrically active phytochromes was used to study the light-regulation of the single-copy nuclear gene encoding plastidic glutamine synthetase (GS-2; EC 6.1.3.2). The de-etiolation of dark-grown aurea mutant seedling cotyledons showed an obligatory dependency on blue light. A limited red light-responsiveness of etiolated aurea cotyledons is, however, retained as seen by the stimulation of both the GS-2 transcript and protein level in the cotyledons of aurea seedlings during growth in red light. The subunits of the octameric GS-2 enzyme were represented by polypeptides with similar electrophoretic mobilities (polypeptides a) in etiolated wild-type or aurea mutant cotyledons. GS-2 proteins with similar apparent molecular masses were also seen in the cotyledons of red light-grown aurea mutant seedlings. In contrast, GS-2 polypeptides with different apparent molecular masses (polypeptides a and b) were detected in the cotyledons of wild-type seedlings grown in red light. This difference indicates that the (post-translational) modification of tomato GS-2 subunit composition is mediated by the photoreceptor phytochrome. The illumination of etiolated wild-type or aurea cotyledons with UV-A- or UV-B-light light resulted in an increase in both the GS-2 transcript and protein level. Following illumination of etiolated wild-type seedlings with UV-A-light, the relative proportion of the GS-2 polypeptides a and b was similar than upon irradiation with blue light but different than after exposure to UV-B- or red light. This result suggests the involvement of a blue/ UV-A-light-specific photoreceptor in the regulation of tomato GS-2 subunit composition. (author)

A survey on knowledge and self-reported formula handling practices of parents and child care workers in Palermo, Italy

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Mammina Caterina

2009-12-01

Full Text Available Abstract Background Powdered infant formula (PIF is not a sterile product, but this information appears to be poorly diffused among child caregivers. Parents and child care workers may behave in an unsafe manner when handling PIF. Methods This study involved parents and child care workers in the 24 municipal child care centres of Palermo. Knowledge and self-reported practices about PIF handling were investigated by a structured questionnaire. A Likert scale was used to measure the strength of the respondent's feelings. Association of knowledge and self-reported practices with demographic variables was also evaluated. Results 42.4% of parents and 71.0% of child care workers filled in the questionnaire. Significant differences were found between parents and child care workers for age and education. 73.2% of parents and 84.4% of child care workers were confident in sterility of PIF. Generally, adherence to safe procedures when reconstituting and handling PIF was more frequently reported by child care workers who, according to the existing legislation, are regularly subjected to a periodic training on food safety principles and practices. Age and education significantly influenced the answers to the questionnaire of both parents and child care workers. Conclusion The results of the study reveal that parents and child care workers are generally unaware that powdered formulas may contain viable microorganisms. However, child care workers consistently chose safer options than parents when answering the questions about adherence to hygienic practices. At present it seems unfeasible to produce sterile PIF, but the risk of growth of hazardous organisms in formula at the time of administration should be minimized by promoting safer behaviours among caregivers to infants in both institutional settings and home.

Risk Factors for Pelvic Insufficiency Fractures in Locally Advanced Cervical Cancer Following Intensity Modulated Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Ramlov, Anne, E-mail: anraml@rm.dk [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Pedersen, Erik Morre; Røhl, Lisbeth [Department of Radiotherapy, Aarhus University Hospital, Aarhus (Denmark); Worm, Esben [Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark); Fokdal, Lars; Lindegaard, Jacob Chr. [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Tanderup, Kari [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark)

2017-04-01

Purpose: To investigate the incidence of and risk factors for pelvic insufficiency fracture (PIF) after definitive chemoradiation therapy for locally advanced cervical cancer (LACC). Methods and Materials: We analyzed 101 patients with LACC treated from 2008-2014. Patients received weekly cisplatin and underwent external beam radiation therapy with 45 Gy in 25 fractions (node-negative patients) or 50 Gy in 25 fractions with a simultaneous integrated boost of 60 Gy in 30 fractions (node-positive patients). Pulsed dose rate magnetic resonance imaging guided adaptive brachytherapy was given in addition. Follow-up magnetic resonance imaging was performed routinely at 3 and 12 months after the end of treatment or based on clinical indication. PIF was defined as a fracture line with or without sclerotic changes in the pelvic bones. D{sub 50%} and V{sub 55Gy} were calculated for the os sacrum and jointly for the os ileum and pubis. Patient- and treatment-related factors including dose were analyzed for correlation with PIF. Results: The median follow-up period was 25 months. The median age was 50 years. In 20 patients (20%), a median of 2 PIFs (range, 1-3 PIFs) were diagnosed; half were asymptomatic. The majority of the fractures were located in the sacrum (77%). Age was a significant risk factor (P<.001), and the incidence of PIF was 4% and 37% in patients aged ≤50 years and patients aged >50 years, respectively. Sacrum D{sub 50%} was a significant risk factor in patients aged >50 years (P=.04), whereas V{sub 55Gy} of the sacrum and V{sub 55Gy} of the pelvic bones were insignificant (P=.33 and P=.18, respectively). A dose-effect curve for sacrum D{sub 50%} in patients aged >50 years showed that reduction of sacrum D{sub 50%} from 40 Gy{sub EQD2} to 35 Gy{sub EQD2} reduces PIF risk from 45% to 22%. Conclusions: PIF is common after treatment of LACC and is mainly seen in patients aged >50 years. Our data indicate that PIFs are not related to lymph node

Packaging-induced failure of semiconductor lasers and optical telecommunications components

Energy Technology Data Exchange (ETDEWEB)

Sharps, J.A. [Corning Inc., NY (United States)

1996-12-31

Telecommunications equipment for field deployment generally have specified lifetimes of > 100,000 hr. To achieve this high reliability, it is common practice to package sensitive components in hermetic, inert gas environments. The intent is to protect components from particulate and organic contamination, oxidation, and moisture. However, for high power density 980 nm diode lasers used in optical amplifiers, the authors found that hermetic, inert gas packaging induced a failure mode not observed in similar, unpackaged lasers. They refer to this failure mode as packaging-induced failure, or PIF. PIF is caused by nanomole amounts of organic contamination which interact with high intensity 980 nm light to form solid deposits over the emitting regions of the lasers. These deposits absorb 980 nm light, causing heating of the laser, narrowing of the band gap, and eventual thermal runaway. The authors have found PIF is averted by packaging with free O{sub 2} and/or a getter material that sequesters organics.

Comparative Genomic Characterization of the Highly Persistent and Potentially Virulent Cronobacter sakazakii ST83, CC65 Strain H322 and Other ST83 Strains

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Hannah R. Chase

2017-06-01

Full Text Available Cronobacter (C. sakazakii is an opportunistic pathogen and has been associated with serious infections with high mortality rates predominantly in pre-term, low-birth weight and/or immune compromised neonates and infants. Infections have been epidemiologically linked to consumption of intrinsically and extrinsically contaminated lots of reconstituted powdered infant formula (PIF, thus contamination of such products is a challenging task for the PIF producing industry. We present the draft genome of C. sakazakii H322, a highly persistent sequence type (ST 83, clonal complex (CC 65, serotype O:7 strain obtained from a batch of non-released contaminated PIF product. The presence of this strain in the production environment was traced back more than 4 years. Whole genome sequencing (WGS of this strain together with four more ST83 strains (PIF production environment-associated confirmed a high degree of sequence homology among four of the five strains. Phylogenetic analysis using microarray (MA and WGS data showed that the ST83 strains were highly phylogenetically related and MA showed that between 5 and 38 genes differed from one another in these strains. All strains possessed the pESA3-like virulence plasmid and one strain possessed a pESA2-like plasmid. In addition, a pCS1-like plasmid was also found. In order to assess the potential in vivo pathogenicity of the ST83 strains, each strain was subjected to infection studies using the recently developed zebrafish embryo model. Our results showed a high (90–100% zebrafish mortality rate for all of these strains, suggesting a high risk for infections and illness in neonates potentially exposed to PIF contaminated with ST83 C. sakazakii strains. In summary, virulent ST83, CC65, serotype CsakO:7 strains, though rarely found intrinsically in PIF, can persist within a PIF manufacturing facility for years and potentially pose significant quality assurance challenges to the PIF manufacturing industry.

Pelvic insufficiency fracture after radiotherapy in patients with cervical cancer in the era of PET/CT

Energy Technology Data Exchange (ETDEWEB)

Park, Shin Hyung; Kim, Jae Chul; Lee, Jeong Eun; Park, In Kyu [Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

2011-12-15

To determine the incidence, risk factors, and clinical characteristics of pelvic insufficiency fracture (PIF) in patients with cervical cancer. Between July 2004 and August 2009, 235 patients with non-metastatic cervical cancer were treated with definitive chemoradiation or postoperative radiotherapy. Among 235 patients, 117 (49.8%) underwent the first positron emission tomography/computed tomography (PET/CT) within 1 year after radiotherapy. The median radiation dose was 55 Gy (range, 45 to 60 Gy). Medical charts and imaging studies, including PET/CT, magnetic resonance imaging (MRI), CT, bone scintigraphy were reviewed to evaluate the patients with PIF. Among 235 patients, 16 developed PIF. The 5-year detection rate of PIF was 9.5%. The 5-year detection rate of PIF in patients who underwent the first PET/CT within a year was 15.6%. The median time to development of PIF was 12.5 months (range, 5 to 30 months). The sites of fracture included 12 sacroiliac joints, 3 pubic rami, 3 iliac bones, and 1 femoral neck. Eleven of 16 patients having PIF complained of hip pain requiring medications. One patient required hospitalization for pain control. The significant risk factors of PIF were old age, body mass index less than 23, bone mineral density less than -3.5 SD, and the first PET/CT within a year after radiotherapy. Radiation dose and concurrent chemotherapy had no impact on PIF rate. PIFs were not rare after pelvic radiotherapy in cervical cancer patients in the era of PET/CT. Timely diagnosis and management of PIF can improve quality of life in patients with cervical cancer, in addition to reducing unnecessary medical expenses.

Pelvic insufficiency fracture after radiotherapy in patients with cervical cancer in the era of PET/CT

International Nuclear Information System (INIS)

Park, Shin Hyung; Kim, Jae Chul; Lee, Jeong Eun; Park, In Kyu

2011-01-01

To determine the incidence, risk factors, and clinical characteristics of pelvic insufficiency fracture (PIF) in patients with cervical cancer. Between July 2004 and August 2009, 235 patients with non-metastatic cervical cancer were treated with definitive chemoradiation or postoperative radiotherapy. Among 235 patients, 117 (49.8%) underwent the first positron emission tomography/computed tomography (PET/CT) within 1 year after radiotherapy. The median radiation dose was 55 Gy (range, 45 to 60 Gy). Medical charts and imaging studies, including PET/CT, magnetic resonance imaging (MRI), CT, bone scintigraphy were reviewed to evaluate the patients with PIF. Among 235 patients, 16 developed PIF. The 5-year detection rate of PIF was 9.5%. The 5-year detection rate of PIF in patients who underwent the first PET/CT within a year was 15.6%. The median time to development of PIF was 12.5 months (range, 5 to 30 months). The sites of fracture included 12 sacroiliac joints, 3 pubic rami, 3 iliac bones, and 1 femoral neck. Eleven of 16 patients having PIF complained of hip pain requiring medications. One patient required hospitalization for pain control. The significant risk factors of PIF were old age, body mass index less than 23, bone mineral density less than -3.5 SD, and the first PET/CT within a year after radiotherapy. Radiation dose and concurrent chemotherapy had no impact on PIF rate. PIFs were not rare after pelvic radiotherapy in cervical cancer patients in the era of PET/CT. Timely diagnosis and management of PIF can improve quality of life in patients with cervical cancer, in addition to reducing unnecessary medical expenses.

Interactions between CYP3A4 and Dietary Polyphenols

Directory of Open Access Journals (Sweden)

Loai Basheer

2015-01-01

Full Text Available The human cytochrome P450 enzymes (P450s catalyze oxidative reactions of a broad spectrum of substrates and play a critical role in the metabolism of xenobiotics, such as drugs and dietary compounds. CYP3A4 is known to be the main enzyme involved in the metabolism of drugs and most other xenobiotics. Dietary compounds, of which polyphenolics are the most studied, have been shown to interact with CYP3A4 and alter its expression and activity. Traditionally, the liver was considered the prime site of CYP3A-mediated first-pass metabolic extraction, but in vitro and in vivo studies now suggest that the small intestine can be of equal or even greater importance for the metabolism of polyphenolics and drugs. Recent studies have pointed to the role of gut microbiota in the metabolic fate of polyphenolics in human, suggesting their involvement in the complex interactions between dietary polyphenols and CYP3A4. Last but not least, all the above suggests that coadministration of drugs and foods that are rich in polyphenols is expected to stimulate undesirable clinical consequences. This review focuses on interactions between dietary polyphenols and CYP3A4 as they relate to structural considerations, food-drug interactions, and potential negative consequences of interactions between CYP3A4 and polyphenols.

Photo-biotechnology as a tool to improve agronomic traits in crops.

Science.gov (United States)

Gururani, Mayank Anand; Ganesan, Markkandan; Song, Pill-Soon

2015-01-01

Phytochromes are photosensory phosphoproteins with crucial roles in plant developmental responses to light. Functional studies of individual phytochromes have revealed their distinct roles in the plant's life cycle. Given the importance of phytochromes in key plant developmental processes, genetically manipulating phytochrome expression offers a promising approach to crop improvement. Photo-biotechnology refers to the transgenic expression of phytochrome transgenes or variants of such transgenes. Several studies have indicated that crop cultivars can be improved by modulating the expression of phytochrome genes. The improved traits include enhanced yield, improved grass quality, shade-tolerance, and stress resistance. In this review, we discuss the transgenic expression of phytochrome A and its hyperactive mutant (Ser599Ala-PhyA) in selected crops, such as Zoysia japonica (Japanese lawn grass), Agrostis stolonifera (creeping bentgrass), Oryza sativa (rice), Solanum tuberosum (potato), and Ipomea batatas (sweet potato). The transgenic expression of PhyA and its mutant in various plant species imparts biotechnologically useful traits. Here, we highlight recent advances in the field of photo-biotechnology and review the results of studies in which phytochromes or variants of phytochromes were transgenically expressed in various plant species. We conclude that photo-biotechnology offers an excellent platform for developing crops with improved properties. Copyright © 2014 Elsevier Inc. All rights reserved.

Mimicking protein-protein interactions through peptide-peptide interactions: HIV-1 gp120 and CXCR4

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Andrea eGross

2013-09-01

Full Text Available We have recently designed a soluble synthetic peptide that functionally mimics the HIV-1 coreceptor CXCR4, which is a chemokine receptor that belongs to the family of seven-transmembrane GPCRs. This CXCR4 mimetic peptide, termed CX4-M1, presents the three extracellular loops (ECLs of the receptor. In binding assays involving recombinant proteins, as well as in cellular infection assays, CX4-M1 was found to selectively recognize gp120 from HIV-1 strains that use CXCR4 for cell entry (X4 tropic HIV-1. Furthermore, anti-HIV-1 antibodies modulate this interaction in a molecular mechanism related to that of their impact on the gp120-CXCR4 interaction. We could now show that the selectivity of CX4-M1 pertains not only to gp120 from X4 tropic HIV-1, but also to synthetic peptides presenting the V3 loops of these gp120 proteins. The V3 loop is thought to be an essential part of the coreceptor binding site of gp120 that contacts the second ECL of the coreceptor. We were able to experimentally confirm this notion in binding assays using substitution analogs of CX4-M1 and the V3 loop peptides, respectively, as well as in cellular infection assays. These results indicate that interactions of the HIV-1 Env with coreceptors can be mimicked by synthetic peptides, which may be useful to explore these interactions at the molecular level in more detail.

Ionospheric cusp flows pulsed by solar wind Alfvén waves

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P. Prikryl

2002-02-01

Full Text Available Pulsed ionospheric flows (PIFs in the cusp foot-print have been observed by the SuperDARN radars with periods between a few minutes and several tens of minutes. PIFs are believed to be a consequence of the interplanetary magnetic field (IMF reconnection with the magnetospheric magnetic field on the dayside magnetopause, ionospheric signatures of flux transfer events (FTEs. The quasiperiodic PIFs are correlated with Alfvénic fluctuations observed in the upstream solar wind. It is concluded that on these occasions, the FTEs were driven by Alfvén waves coupling to the day-side magnetosphere. Case studies are presented in which the dawn-dusk component of the Alfvén wave electric field modulates the reconnection rate as evidenced by the radar observations of the ionospheric cusp flows. The arrival of the IMF southward turning at the magnetopause is determined from multipoint solar wind magnetic field and/or plasma measurements, assuming plane phase fronts in solar wind. The cross-correlation lag between the solar wind data and ground magnetograms that were obtained near the cusp footprint exceeded the estimated spacecraft-to-magnetopause propagation time by up to several minutes. The difference can account for and/or exceeds the Alfvén propagation time between the magnetopause and ionosphere. For the case of short period ( < 13 min PIFs, the onset times of the flow transients appear to be further delayed by at most a few more minutes after the IMF southward turning arrived at the magnetopause. For the case of long period (30 – 40 min PIFs, the observed additional delays were 10–20 min. We interpret the excess delay in terms of an intrinsic time scale for reconnection (Russell et al., 1997 which can be explained by the surface-wave induced magnetic reconnection mechanism (Uberoi et al., 1999. Here, surface waves with wavelengths larger than the thickness of the neutral layer induce a tearing-mode instability whose rise time explains the

Post Pelvic Radiotherapy Bony Changes

Energy Technology Data Exchange (ETDEWEB)

Huh, Seung Jae [Samsung Medical Center, Seoul (Korea, Republic of)

2009-03-15

There has been recent interest in radiation-induced bone injury in clinical conditions, especially for pelvic insufficiency fracture (PIF). A PIF is caused by the effect of normal or physiological stress on bone with demineralization and decreased elastic resistance. Pelvic radiotherapy (RT) can also contribute to the development of a PIF. A PIF has been regarded as a rare complication with the use of megavoltage equipment. However, recent studies have reported the incidence of PIFs as 8.2{approx}20% after pelvic RT in gynecological patients, an incidence that was higher than previously believed. The importance of understanding a PIF lies in the potential for misdiagnosis as a bony metastasis. If patients complain of pelvic pain after whole-pelvis radiation therapy, the presence of a PIF must be considered in the differential diagnosis. The use of multibeam arrangements and conformal RT to reduce the volume and dose of irradiated pelvic bone can be helpful to minimize the risk of fracture. In addition to a PIF, osteonecrosis and avascular necrosis of the femoral head can develop after radiation therapy. Osteoradionecrosis of the pelvic bone is a clinical diagnostic challenge that must be differentiated from an osseous metastasis. A post-radiation bone sarcoma can result as a long-term sequela of pelvic irradiation for uterine cervical cancer.

Interaction of Np(4) and Pu(4) with diisoamylphosphoric acid

International Nuclear Information System (INIS)

Sokhina, L.P.; Rovnyj, S.I.; Goncharuk, L.V.; Sladkova, M.V.; Tyumentseva, L.M.

1988-01-01

Interaction of neptunium (4) and plutonium (4) with diisoamylphosphoric acid (HD) in nitric acid solutions is investigated. It is ascertained that depending on mole ratio of HD and Np(Pu) in solution three types of compounds: Me (NO 3 ) 2 D 2 , Me(NO 3 ) 2 D 2 ·2HD and Me(NO 3 ) 2 D 2 ·4HD, are formed. The solubility of neptunium (plutonium) diisoamylphosphates in nitric acid, oxalate, carbonate and organic solutions, is determined. The possibility of the compound depositions in the extraction equipment should be taken into account in the process of spent fuel regeneration, when 30% HD solutions in n-paraffins are used as extractants

4C-ker: A Method to Reproducibly Identify Genome-Wide Interactions Captured by 4C-Seq Experiments.

Science.gov (United States)

Raviram, Ramya; Rocha, Pedro P; Müller, Christian L; Miraldi, Emily R; Badri, Sana; Fu, Yi; Swanzey, Emily; Proudhon, Charlotte; Snetkova, Valentina; Bonneau, Richard; Skok, Jane A

2016-03-01

4C-Seq has proven to be a powerful technique to identify genome-wide interactions with a single locus of interest (or "bait") that can be important for gene regulation. However, analysis of 4C-Seq data is complicated by the many biases inherent to the technique. An important consideration when dealing with 4C-Seq data is the differences in resolution of signal across the genome that result from differences in 3D distance separation from the bait. This leads to the highest signal in the region immediately surrounding the bait and increasingly lower signals in far-cis and trans. Another important aspect of 4C-Seq experiments is the resolution, which is greatly influenced by the choice of restriction enzyme and the frequency at which it can cut the genome. Thus, it is important that a 4C-Seq analysis method is flexible enough to analyze data generated using different enzymes and to identify interactions across the entire genome. Current methods for 4C-Seq analysis only identify interactions in regions near the bait or in regions located in far-cis and trans, but no method comprehensively analyzes 4C signals of different length scales. In addition, some methods also fail in experiments where chromatin fragments are generated using frequent cutter restriction enzymes. Here, we describe 4C-ker, a Hidden-Markov Model based pipeline that identifies regions throughout the genome that interact with the 4C bait locus. In addition, we incorporate methods for the identification of differential interactions in multiple 4C-seq datasets collected from different genotypes or experimental conditions. Adaptive window sizes are used to correct for differences in signal coverage in near-bait regions, far-cis and trans chromosomes. Using several datasets, we demonstrate that 4C-ker outperforms all existing 4C-Seq pipelines in its ability to reproducibly identify interaction domains at all genomic ranges with different resolution enzymes.

4C-ker: A Method to Reproducibly Identify Genome-Wide Interactions Captured by 4C-Seq Experiments.

Directory of Open Access Journals (Sweden)

Ramya Raviram

2016-03-01

Full Text Available 4C-Seq has proven to be a powerful technique to identify genome-wide interactions with a single locus of interest (or "bait" that can be important for gene regulation. However, analysis of 4C-Seq data is complicated by the many biases inherent to the technique. An important consideration when dealing with 4C-Seq data is the differences in resolution of signal across the genome that result from differences in 3D distance separation from the bait. This leads to the highest signal in the region immediately surrounding the bait and increasingly lower signals in far-cis and trans. Another important aspect of 4C-Seq experiments is the resolution, which is greatly influenced by the choice of restriction enzyme and the frequency at which it can cut the genome. Thus, it is important that a 4C-Seq analysis method is flexible enough to analyze data generated using different enzymes and to identify interactions across the entire genome. Current methods for 4C-Seq analysis only identify interactions in regions near the bait or in regions located in far-cis and trans, but no method comprehensively analyzes 4C signals of different length scales. In addition, some methods also fail in experiments where chromatin fragments are generated using frequent cutter restriction enzymes. Here, we describe 4C-ker, a Hidden-Markov Model based pipeline that identifies regions throughout the genome that interact with the 4C bait locus. In addition, we incorporate methods for the identification of differential interactions in multiple 4C-seq datasets collected from different genotypes or experimental conditions. Adaptive window sizes are used to correct for differences in signal coverage in near-bait regions, far-cis and trans chromosomes. Using several datasets, we demonstrate that 4C-ker outperforms all existing 4C-Seq pipelines in its ability to reproducibly identify interaction domains at all genomic ranges with different resolution enzymes.

Surveillance and molecular typing of Cronobacter spp. in commercial powdered infant formula and follow-up formula from 2011 to 2013 in Shandong Province, China.

Science.gov (United States)

Zhang, Huaning; Hou, Peibin; Lv, Hui; Chen, Yuzhen; Li, Xinpeng; Ren, Yanyan; Wang, Mei; Tan, Hailian; Bi, Zhenwang

2017-05-01

Infection with Cronobacter spp. leads to neonatal meningitis, necrotizing enterocolitis and bacteremia. Cronobacter spp. are reported to comprise an important pathogen contaminating powdered infant formula (PIF) and follow-up formula (FUF), although little is known about the contamination level of Cronobacter spp. in PIFs and FUFs in China. In total, 1032 samples were collected between 2011 and 2013. Forty-two samples were positive, including 1.6% in PIFs and 6.5% in FUFs. The strains were susceptible to most antibiotics except for cefoxitin. Pulsed-field gel electrophoresis after XbaI digestion produced a total of 36 banding patterns. The 38 strains were found in 27 sequence types (STs), of which nine types (ST454 to ST462) had not been reported in other countries. The clinically relevant strains obtained from the 38 isolates in the present study comprised three ST3, two ST4, two ST8 and one ST1. The contamination rate in the PIF and FUF has stayed at a relatively high level. The contamination rate of PIF was significantly lower than FUF. The isolates had high susceptibility to the antibiotics tested, except cefoxitin. There were polymorphisms between the Cronobacter spp. as indicated by pulsed-field gel electrophoresis and multilocus sequence typing. Therefore, contamination with Cronobacter spp. remains a current issue for commercial infant formulas in China. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Embedding methods for phi4-interaction

International Nuclear Information System (INIS)

Hanckowiak, J.

1985-01-01

The idea of embedding a given theory in a class of similar theories is applied to quantum field theory in the case of phi 4 -interaction to derive different equations for the generating functional. The number of possible embeddings has been restricted by demanding that for the defined projections of the generating functional a closed system of equations be obtained

Sorghum phytochrome B inhibits flowering in long days by activating expression of SbPRR37 and SbGHD7, repressors of SbEHD1, SbCN8 and SbCN12.

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Shanshan Yang

Full Text Available Light signaling by phytochrome B in long days inhibits flowering in sorghum by increasing expression of the long day floral repressors PSEUDORESPONSE REGULATOR PROTEIN (SbPRR37, Ma1 and GRAIN NUMBER, PLANT HEIGHT AND HEADING DATE 7 (SbGHD7, Ma6. SbPRR37 and SbGHD7 RNA abundance peaks in the morning and in the evening of long days through coordinate regulation by light and output from the circadian clock. 58 M, a phytochrome B deficient (phyB-1, ma3R genotype, flowered ∼60 days earlier than 100 M (PHYB, Ma3 in long days and ∼11 days earlier in short days. Populations derived from 58 M (Ma1, ma3R, Ma5, ma6 and R.07007 (Ma1, Ma3, ma5, Ma6 varied in flowering time due to QTL aligned to PHYB/phyB-1 (Ma3, Ma5, and GHD7/ghd7-1 (Ma6. PHYC was proposed as a candidate gene for Ma5 based on alignment and allelic variation. PHYB and Ma5 (PHYC were epistatic to Ma1 and Ma6 and progeny recessive for either gene flowered early in long days. Light signaling mediated by PhyB was required for high expression of the floral repressors SbPRR37 and SbGHD7 during the evening of long days. In 100 M (PHYB the floral activators SbEHD1, SbCN8 and SbCN12 were repressed in long days and de-repressed in short days. In 58 M (phyB-1 these genes were highly expressed in long and short days. Furthermore, SbCN15, the ortholog of rice Hd3a (FT, is expressed at low levels in 100 M but at high levels in 58 M (phyB-1 regardless of day length, indicating that PhyB regulation of SbCN15 expression may modify flowering time in a photoperiod-insensitive manner.

Cognitive modeling and dynamic probabilistic simulation of operating crew response to complex system accidents. Part 4: IDAC causal model of operator problem-solving response

Energy Technology Data Exchange (ETDEWEB)

Chang, Y.H.J. [Center for Risk and Reliability, University of Maryland, College Park, MD 20742 (United States) and Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)]. E-mail: yhc@umd.edu; Mosleh, A. [Center for Risk and Reliability, University of Maryland, College Park, MD 20742 (United States)

2007-08-15

This is the fourth in a series of five papers describing the Information, Decision, and Action in Crew context (IDAC) operator response model for human reliability analysis. An example application of this modeling technique is also discussed in this series. The model has been developed to probabilistically predicts the responses of a nuclear power plant control room operating crew in accident conditions. The operator response spectrum includes cognitive, emotional, and physical activities during the course of an accident. This paper assesses the effects of the performance-influencing factors (PIFs) affecting the operators' problem-solving responses including information pre-processing (I), diagnosis and decision making (D), and action execution (A). Literature support and justifications are provided for the assessment on the influences of PIFs.

Cognitive modeling and dynamic probabilistic simulation of operating crew response to complex system accidents. Part 4: IDAC causal model of operator problem-solving response

International Nuclear Information System (INIS)

Chang, Y.H.J.; Mosleh, A.

2007-01-01

This is the fourth in a series of five papers describing the Information, Decision, and Action in Crew context (IDAC) operator response model for human reliability analysis. An example application of this modeling technique is also discussed in this series. The model has been developed to probabilistically predicts the responses of a nuclear power plant control room operating crew in accident conditions. The operator response spectrum includes cognitive, emotional, and physical activities during the course of an accident. This paper assesses the effects of the performance-influencing factors (PIFs) affecting the operators' problem-solving responses including information pre-processing (I), diagnosis and decision making (D), and action execution (A). Literature support and justifications are provided for the assessment on the influences of PIFs

Matching the $D^{6}R^{4}$ interaction at two-loops

CERN Document Server

D'Hoker, Eric; Pioline, Boris; Russo, Rodolfo

2015-01-01

The coefficient of the $D^6 {\\cal R}^4$ interaction in the low energy expansion of the two-loop four-graviton amplitude in type II superstring theory is known to be proportional to the integral of the Zhang-Kawazumi (ZK) invariant over the moduli space of genus-two Riemann surfaces. We demonstrate that the ZK invariant is an eigenfunction with eigenvalue 5 of the Laplace-Beltrami operator in the interior of moduli space. Exploiting this result, we evaluate the integral of the ZK invariant explicitly, finding agreement with the value of the two-loop $D^6 {\\cal R}^4$ interaction predicted on the basis of S-duality and supersymmetry. A review of the current understanding of the $D^{2p} {\\cal R}^4$ interactions in type II superstring theory compactified on a torus $T^d$ with $p \\leq 3$ and $d \\leq 4$ is included.

Influence of O_2 exposure on the interaction between CH_4 and amorphous AlYB_1_4

International Nuclear Information System (INIS)

Hunold, Oliver; Wiesing, Martin; Arcos, Teresa de los; Music, Denis; Grundmeier, Guido; Schneider, Jochen M.

2017-01-01

Highlights: • Influence of O_2 exposure on the surface chemistry of a-AlYB_1_4 on the interaction with CH_4 and PE studied by ab initio and UHV-AFM. • Predicted stronger interaction is consistent with experimentally observed trends. • Upon O_2 exposure surface bonding becomes more semiconducting causing a charge redistribution within the adsorbed CH_4 molecule. • The data serve as proof of concept for exploring polymer − hard coating interactions in varying atmospheres. - Abstract: The influence of surface oxidation on the interaction between CH_4 and amorphous AlYB_1_4 (a-AlYB_1_4) has been studied theoretically by using density functional theory and experimentally by ultra-high vacuum atomic force microscopy (UHV-AFM). CH_4 mimics the –CH_3 termination and aliphatic subunits of a polymer chain. Low-energy ion scattering measurements of magnetron sputtered thin films suggest that the bonding at the surfaces of pristine a-AlYB_1_4 and O_2 exposed a-AlYB_1_4 (O_2//a-AlYB_1_4) is metal-boron and metal-oxygen dominated, respectively. Based on the ab initio calculations the adsorption energies of CH_4 on a-AlYB_1_4 and O_2//a-AlYB_1_4 decreases from −0.07 to −0.30 eV, respectively. This trend is consistent with experimental data obtained by colloidal probe UHV-AFM studies with a polyethylene sphere, where larger adhesion forces for the O_2 exposed surface as compared to the pristine a-AlYB_1_4 surface were measured. No charge transfer takes place between CH_4 and the pristine as well as the O_2 exposed a-AlYB_1_4. Oxygen chemisorption induces changes in surface bonding. States at the Fermi level are depleted upon oxidation, hence the surface bonding becomes more semiconducting causing a charge redistribution within the adsorbed CH_4 molecule. Hence, these data serve as proof of concept for exploring the effect of O_2 exposure on the interaction between aliphatic polymers and a-AlYB_1_4 using a correlative experimental and theoretical research approach.

An improved model for nucleation-limited ice formation in living cells during freezing.

Directory of Open Access Journals (Sweden)

Jingru Yi

Full Text Available Ice formation in living cells is a lethal event during freezing and its characterization is important to the development of optimal protocols for not only cryopreservation but also cryotherapy applications. Although the model for probability of ice formation (PIF in cells developed by Toner et al. has been widely used to predict nucleation-limited intracellular ice formation (IIF, our data of freezing Hela cells suggest that this model could give misleading prediction of PIF when the maximum PIF in cells during freezing is less than 1 (PIF ranges from 0 to 1. We introduce a new model to overcome this problem by incorporating a critical cell volume to modify the Toner's original model. We further reveal that this critical cell volume is dependent on the mechanisms of ice nucleation in cells during freezing, i.e., surface-catalyzed nucleation (SCN and volume-catalyzed nucleation (VCN. Taken together, the improved PIF model may be valuable for better understanding of the mechanisms of ice nucleation in cells during freezing and more accurate prediction of PIF for cryopreservation and cryotherapy applications.

Cronobacter species contamination of powdered infant formula and the implications for neonatal health

Directory of Open Access Journals (Sweden)

Gautam eKalyatanda

2015-07-01

Full Text Available Cronobacter is a class of Enterobacteriaceae that cause infections in neonates, especially those born prematurely. Over 90% of these infections have been linked epidemiologically to powdered infant formula (PIF. Contamination of PIF can occur at manufacture, reconstitution, or storage of reconstituted product. Intrinsic properties that enable Cronobacter to cause disease include resistance to heat, ultraviolet radiation, oxygen radicals, stomach acids, and pasteurization; an ability to utilize sialic acid (a nutrition additive to PIF that facilitates the organism’s growth and survival; and an exceptional affinity for biofilms in enteral feeding tubes. As part of ongoing endeavors to reduce the incidence of neonatal PIF-associated Cronobacter infections, the World Health Organization (WHO and the U.S. Food and Drug Administration (FDA have established guidelines for PIF production, preparation for infant feeding, and storage of reconstituted product.

Electronic structure and exchange interactions in GdB{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Baranovskiy, A., E-mail: andriy.baranovskiy@gmail.com; Grechnev, A.

2015-02-01

The electronic structure of the antiferromagnetic Shastry–Sutherland compound GdB{sub 4} has been analyzed with density functional theory and the all-electron full-potential linearized augmented-plane wave (FP-LAPW) code. Different magnetic configurations, including the realistic dimer one, have been considered. The exchange interactions were found to be J{sub 1}/k{sub B}=−12K and J{sub 2}/k{sub B}=−2–0.8K, where, J{sub 1} and J{sub 2} are the diagonal exchange interaction and the exchange interaction along the edges of a square, respectively. - Highlights: • Electronic structure of AFM Shastry–Sutherland compound GB{sub 4} is calculated. • The mechanism of exchange parameters evaluation within Heisenberg model is proposed. • Calculated exchange parameters are found to be in agreement with experimental data. • Higher-order exchange interactions are important for dimer structure stabilizing.

Light Controls Cytokinin Signaling via Transcriptional Regulation of Constitutively Active Sensor Histidine Kinase CKI1.

Science.gov (United States)

Dobisova, Tereza; Hrdinova, Vendula; Cuesta, Candela; Michlickova, Sarka; Urbankova, Ivana; Hejatkova, Romana; Zadnikova, Petra; Pernisova, Marketa; Benkova, Eva; Hejatko, Jan

2017-05-01

In plants, the multistep phosphorelay (MSP) pathway mediates a range of regulatory processes, including those activated by cytokinins. The cross talk between cytokinin response and light has been known for a long time. However, the molecular mechanism underlying the interaction between light and cytokinin signaling remains elusive. In the screen for upstream regulators we identified a LONG PALE HYPOCOTYL ( LPH ) gene whose activity is indispensable for spatiotemporally correct expression of CYTOKININ INDEPENDENT1 ( CKI1 ), encoding the constitutively active sensor His kinase that activates MSP signaling. lph is a new allele of HEME OXYGENASE1 ( HY1 ) that encodes the key protein in the biosynthesis of phytochromobilin, a cofactor of photoconvertible phytochromes. Our analysis confirmed the light-dependent regulation of the CKI1 expression pattern. We show that CKI1 expression is under the control of phytochrome A (phyA), functioning as a dual (both positive and negative) regulator of CKI1 expression, presumably via the phyA-regulated transcription factors (TF) PHYTOCHROME INTERACTING FACTOR3 and CIRCADIAN CLOCK ASSOCIATED1. Changes in CKI1 expression observed in lph / hy1 - 7 and phy mutants correlate with misregulation of MSP signaling, changed cytokinin sensitivity, and developmental aberrations that were previously shown to be associated with cytokinin and/or CKI1 action. Besides that, we demonstrate a novel role of phyA-dependent CKI1 expression in the hypocotyl elongation and hook development during skotomorphogenesis. Based on these results, we propose that the light-dependent regulation of CKI1 provides a plausible mechanistic link underlying the well-known interaction between light- and cytokinin-controlled plant development. © 2017 American Society of Plant Biologists. All Rights Reserved.

Human IgG4 binds to IgG4 and conformationally altered IgG1 via Fc-Fc interactions

NARCIS (Netherlands)

Rispens, Theo; Ooievaar-de Heer, Pleuni; Vermeulen, Ellen; Schuurman, Janine; van der Neut Kolfschoten, Marijn; Aalberse, Rob C.

2009-01-01

The Fc fragment of IgG4 can interact with the Fc fragment of another IgG molecule. This interaction is a confounding factor when measuring IgG4 rheumatoid factor levels. Recently, we demonstrated that half-molecules of IgG4 can exchange to form a bispecific Ab. We expected these two phenomena to be

DNA interaction studies of sesamol (3,4-methylenedioxyphenol) food additive.

Science.gov (United States)

Kashanian, Soheila; Tahmasian Ghobadi, Ameneh; Roshanfekr, Hamideh; Shariati, Zohreh

2013-02-01

The interaction of native calf thymus DNA (CT-DNA) with sesamol (3,4-methylenedioxyphenol) in Tris-HCl buffer at neutral pH 7.4 was monitored by absorption spectrophotometry, viscometry and spectrofluorometry. It is found that sesamol molecules could interact with DNA outside and/or groove binding modes, as are evidenced by: hyperchromism in UV absorption band, very slow decrease in specific viscosity of DNA, and small increase in the fluorescence of methylene blue (MB)-DNA solutions in the presence of increasing amounts of sesamol, which indicates that it is able to partially release the bound MB. Furthermore, the enthalpy and entropy of the reaction between sesamol and CT-DNA showed that the reaction is enthalpy-favored and entropy-disfavored (ΔH = -174.08 kJ mol(-1); ΔS = -532.92 J mol(-1) K(-1)). The binding constant was determined using absorption measurement and found to be 2.7 × 10(4) M(-1); its magnitude suggests that sesamol interacts to DNA with a high affinity.

In vitro study on the interaction of 4,4-dimethylcurcumin with calf thymus DNA

Energy Technology Data Exchange (ETDEWEB)

Liu, Bing-Mi, E-mail: liubingmi@163.com [Department of Pharmacy, Liaoning University, Shenyang 110036 (China); Bai, Chong-Liang [Centre for Molecular Science and Engineering, Northeastern University, Shenyang 110819 (China); Zhang, Jun; Liu, Yang; Dong, Bo-Yang; Zhang, Yi-Tong [Department of Pharmacy, Liaoning University, Shenyang 110036 (China); Liu, Bin, E-mail: liubinzehao@163.com [Department of Pharmacy, Liaoning University, Shenyang 110036 (China)

2015-10-15

The interaction of 4,4-dimethylcurcumin (DMCU), a synthesized analog of curcumin, with calf-thymus DNA (ct-DNA) was investigated using fluorescence, absorption, and circular dichroism (CD) spectroscopy, coupled with viscosity measurements and molecular docking techniques. DMCU was found to bind to ct-DNA with moderate binding affinity through groove binding as evidenced by a decrease in the absorption intensity in combination with no obvious change in the relative specific viscosity of ct-DNA and the CD spectrum. Thermodynamic analysis of the fluorescence data obtained at different temperatures suggested that the binding process was spontaneous and was primarily driven by hydrogen bonding and van der Waals forces. Furthermore, competitive binding experiments with ethidium bromide and 4′,6-diamidino-2-phenylindole as probes showed that DMCU could preferentially bind in the minor groove of double-stranded DNA. The results obtained from the molecular docking studies were consistent with these experimental results. This study explored the potential applicability of the spectroscopic properties of DMCU for studying its interactions with relevant biological or biomimicking targets. - Highlights: • 4,4-dimethylcurcumin (DMCU) has strong fluorescence characteristics. • DMCU could bind to DNA through groove binding. • Docking studies revealed that DMCU bound to the A–T region in the minor groove.

Simulation of AntiMatter–Matter Interactions in Geant4

Directory of Open Access Journals (Sweden)

Galoyan Aida

2018-01-01

Full Text Available Cross sections of antiproton and antinucleus interactions with nuclei are calculated using stochastic averaging method. A new implementation of the Quark-Gluon-String Model (QGSM is proposed for simulation of multi-particle production in antinucleus-nucleus collisions. A combination of the cross sections and the new implementation of QGSM allows experimental data on antiproton and antinucleus interactions with nuclei to be described. The combination is included in the well-known Geant4 simulation toolkit.

Two-dimensional electric field measurements in the ionospheric footprint of a flux transfer event

Directory of Open Access Journals (Sweden)

K. A. McWilliams

2000-12-01

Full Text Available Line-of-sight Doppler velocities from the SuperDARN CUTLASS HF radar pair have been combined to produce the first two-dimensional vector measurements of the convection pattern throughout the ionospheric footprint of a flux transfer event (a pulsed ionospheric flow, or PIF. Very stable and moderate interplanetary magnetic field conditions, along with a preceding prolonged period of northward interplanetary magnetic field, allow a detailed study of the spatial and the temporal evolution of the ionospheric response to magnetic reconnection. The flux tube footprint is tracked for half an hour across six hours of local time in the auroral zone, from magnetic local noon to dusk. The motion of the footprint of the newly reconnected flux tube is compared with the ionospheric convection velocity. Two primary intervals in the PIF's evolution have been determined. For the first half of its lifetime in the radar field of view the phase speed of the PIF is highly variable and the mean speed is nearly twice the ionospheric convection speed. For the final half of its lifetime the phase velocity becomes much less variable and slows down to the ionospheric convection velocity. The evolution of the flux tube in the magnetosphere has been studied using magnetic field, magnetopause and magnetosheath models. The data are consistent with an interval of azimuthally propagating magnetopause reconnection, in a manner consonant with a peeling of magnetic flux from the magnetopause, followed by an interval of anti-sunward convection of reconnected flux tubes.Key words: Magnetospheric physics (magnetosphere · ionosphere interactions; plasma convection; solar wind · magnetosphere interactions

Responses of He-Ne laser on agronomic traits and the crosstalk between UVR8 signaling and phytochrome B signaling pathway in Arabidopsis thaliana subjected to supplementary ultraviolet-B (UV-B) stress.

Science.gov (United States)

Gao, Limei; Li, Yongfeng; Shen, Zhihua; Han, Rong

2018-05-01

UV-B acclimation effects and UV-B damage repair induced by a 632.8-nm He-Ne laser were investigated in Arabidopsis thaliana plants in response to supplementary UV-B stress. There was an increasing trend in growth parameters in the combination-treated plants with He-Ne laser and UV-B light compared to those stressed with enhanced UV-B light alone during different developmental stages of plants. The photosynthetic efficiency (Pn) and survival rates of seedlings were significantly higher in the combination treatments than UV-B stress alone. The expression of UVR8, phytochrome B (PhyB), and their mediated signal responsive genes such as COP1, HY5, and CHS were also significantly upregulated in plants with the laser irradiation compared with other groups without the laser. Levels of flavonol accumulation in leaves and capsule yield of He-Ne laser-treated plants were increased. The phyB-9 mutants were more sensitive to enhanced UV-B stress and had no obvious improvements in plant phenotypic development and physiological damage caused by enhanced UV-B stress after He-Ne laser irradiation. Our results suggested that UVR8 and its mediated signaling pathway via interaction with COP1 can be induced by He-Ne laser, and these processes were dependent on cytoplasmic PhyB levels in plant cells, which might be one of the most important mechanisms of He-Ne laser on UV-B protection and UV-B damage repair. These current data have also elucidated that the biostimulatory effects of He-Ne laser on Arabidopsis thaliana plants would happen not only during the early growth stage but also during the entire late developmental stage.

Structural interactions between lipids, water and S1-S4 voltage-sensing domains.

Science.gov (United States)

Krepkiy, Dmitriy; Gawrisch, Klaus; Swartz, Kenton J

2012-11-02

Membrane proteins serve crucial signaling and transport functions, yet relatively little is known about their structures in membrane environments or how lipids interact with these proteins. For voltage-activated ion channels, X-ray structures suggest that the mobile voltage-sensing S4 helix would be exposed to the membrane, and functional studies reveal that lipid modification can profoundly alter channel activity. Here, we use solid-state NMR to investigate structural interactions of lipids and water with S1-S4 voltage-sensing domains and to explore whether lipids influence the structure of the protein. Our results demonstrate that S1-S4 domains exhibit extensive interactions with lipids and that these domains are heavily hydrated when embedded in a membrane. We also find evidence for preferential interactions of anionic lipids with S1-S4 domains and that these interactions have lifetimes on the timescale of ≤ 10(-3)s. Arg residues within S1-S4 domains are well hydrated and are positioned in close proximity to lipids, exhibiting local interactions with both lipid headgroups and acyl chains. Comparative studies with a positively charged lipid lacking a phosphodiester group reveal that this lipid modification has only modest effects on the structure and hydration of S1-S4 domains. Taken together, our results demonstrate that Arg residues in S1-S4 voltage-sensing domains reside in close proximity to the hydrophobic interior of the membrane yet are well hydrated, a requirement for carrying charge and driving protein motions in response to changes in membrane voltage. Published by Elsevier Ltd.

Interaction between doubly-excited 4p4nln'l' resonances in KrI

International Nuclear Information System (INIS)

Sukhorukov, V L; Petrov, I D; Demekhin, Ph V; Schmoranzer, H; Mickat, S; Kammer, S; Schartner, K-H; Klumpp, S; Werner, L; Ehresmann, A

2007-01-01

Photoionization cross sections for the 4p 4 ( 3 P)5s 4 P 5/2,3/2,1/2 satellites and 4s → εl, 4p → εl main lines of Kr II were measured using the photon-induced fluorescence spectroscopy in the exciting-photon energy range between 27.80 eV and 29.44 eV with extremely narrow bandwidth (1.7 meV at 28.55 eV) of the monochromatized synchrotron radiation. The observed resonances were assigned to the 4p 4 5s( 4 P 1/2 )np and 4p 4 5s( 2 P 3/2 )np Rydberg series on the basis of the calculations including core relaxation and interaction between many resonances and many continua. The calculation shows that the resonance structure in the photoionization channels exists due to the 4p 4 ( 1 D)5s 2 D 5/2 6p 3/2 and 4p 4 ( 1 D)5s 2 D 3/2 6p 3/2,1/2 promoter states which strongly perturb the above Rydberg series

[Interaction of FABP4 with plasma membrane proteins of endothelial cells].

Science.gov (United States)

Saavedra, Paula; Girona, Josefa; Aragonès, Gemma; Cabré, Anna; Guaita, Sandra; Heras, Mercedes; Masana, Lluís

2015-01-01

Fatty acid binding protein (FABP4) is an adipose tissue-secreted adipokine implicated in the regulation of the energetic metabolism and inflammation. High levels of circulating FABP4 have been described in people with obesity, atherogenic dyslipidemia, diabetes and metabolic syndrome. Recent studies have demonstrated that FABP4 could have a direct effect on peripheral tissues and, specifically, on vascular function. It is still unknown how the interaction between FABP4 and the endothelial cells is produced to prompt these effects on vascular function. The objective of this work is studying the interaction between FABP4 and the plasma membrane proteins of endothelial cells. HUVEC cells were incubated with and without FABP4 (100 ng/ml) for 5 minutes. Immunolocalization of FABP4 was studied by confocal microscopy. The results showed that FABP4 colocalizates with CD31, a membrane protein marker. A strategy which combines 6XHistidine-tag FABP4 (FABP4-His), incubations with or without FABP4-His (100 ng/ml), formaldehyde cross-linking, cellular membrane protein extraction and western blot, was designed to study the FABP4 interactions with membrane proteins of HUVECs. The results showed different western blot profiles depending of the incubation with or without FABP4-His. The immunoblot revelead three covalent protein complexes of about 108, 77 and 33 kDa containing FAPB4 and its putative receptor. The existence of a specific binding protein complex able to bind FABP4 to endothelial cells is supported by these results. The obtained results will permit us advance in the molecular knowledge of FABP4 effects as well as use this protein and its receptor as therapeutic target to prevent cardiovascular. Copyright © 2014 Sociedad Española de Arteriosclerosis. Published by Elsevier España. All rights reserved.

MVP interacts with YPEL4 and inhibits YPEL4-mediated activities of the ERK signal pathway.

Science.gov (United States)

Liang, Pei; Wan, Yongqi; Yan, Yan; Wang, Yuequn; Luo, Na; Deng, Yun; Fan, Xiongwei; Zhou, Junmei; Li, Yongqing; Wang, Zequn; Yuan, Wuzhou; Tang, Ming; Mo, Xiaoyang; Wu, Xiushan

2010-06-01

Human YPEL4 is a member of YPEL family. It contains a Yippee domain, which is a putative zinc-finger-like, metal-binding domain. The human YPEL4 gene maps to chromosome 11q12.1, is ubiquitously expressed in adult tissues, and encodes a nuclear protein of 127 amino acids, the function of which remains unknown. To gain insights into the cellular function of this protein, we searched for YPEL4-interacting proteins using a yeast two-hybrid screen. The major vault protein (MVP), a lung resistance associated protein, was identified as a binding partner of YPEL4. The interaction between YPEL4 and MVP in mammalian cells was further demonstrated by a series of biochemical assays including the mammalian two-hybrid assay, GST pull-down assay, co-immunoprecipitation assay, and immunocytochemistry. Using a reporter system, we found that MVP can inhibit YPEL4's ability to activate Elk-1 in the MAPK signaling pathway. This study provides new clues for understanding the molecular mechanism of YPEL4 in cell division and signal transduction pathways and should be helpful for understanding molecular functions of the YPEL family.

Helper component proteinase of the genus Potyvirus is an interaction partner of translation initiation factors eIF(iso)4E and eIF4E and contains a 4E binding motif.

Science.gov (United States)

Ala-Poikela, Marjo; Goytia, Elisa; Haikonen, Tuuli; Rajamäki, Minna-Liisa; Valkonen, Jari P T

2011-07-01

The multifunctional helper component proteinase (HCpro) of potyviruses (genus Potyvirus; Potyviridae) shows self-interaction and interacts with other potyviral and host plant proteins. Host proteins that are pivotal to potyvirus infection include the eukaryotic translation initiation factor eIF4E and the isoform eIF(iso)4E, which interact with viral genome-linked protein (VPg). Here we show that HCpro of Potato virus A (PVA) interacts with both eIF4E and eIF(iso)4E, with interactions with eIF(iso)4E being stronger, as judged by the data of a yeast two-hybrid system assay. A bimolecular fluorescence complementation assay on leaves of Nicotiana benthamiana showed that HCpro from three potyviruses (PVA, Potato virus Y, and Tobacco etch virus) interacted with the eIF(iso)4E and eIF4E of tobacco (Nicotiana tabacum); interactions with eIF(iso)4E and eIF4E of potato (Solanum tuberosum) were weaker. In PVA-infected cells, interactions between HCpro and tobacco eIF(iso)4E were confined to round structures that colocalized with 6K2-induced vesicles. Point mutations introduced to a 4E binding motif identified in the C-terminal region of HCpro debilitated interactions of HCpro with translation initiation factors and were detrimental to the virulence of PVA in plants. The 4E binding motif conserved in HCpro of potyviruses and HCpro-initiation factor interactions suggest new roles for HCpro and/or translation factors in the potyvirus infection cycle.

Interaction between resonances through autoionization continua near the 4s-threshold in KrII

International Nuclear Information System (INIS)

Demekhin, Ph V; Petrov, I D; Lagutin, B M; Sukhorukov, V L; Vollweiler, F; Klumpp, S; Ehresmann, A; Schartner, K-H; Schmoranzer, H

2005-01-01

The interaction between resonances through autoionization continua and the interaction between autoionization continua were investigated theoretically and experimentally for the photoionization process of the 4p- and 4s-shells and for the population of 4p 4 ( 3 P)5s 4 P J , 4p 4 ( 3 P)5s 2 P J and 4p 4 ( 3 P)4d 4 D J satellites of KrII. Cross sections for the satellite production and the angular distribution parameter of the fluorescence radiation were measured by photon-induced fluorescence spectroscopy after excitationx with linearly polarized monochromatized synchrotron radiation at exciting-photon energies between 28.45 eV and 29.95 eV with an exciting-photon energy resolution of 10 meV (FWHM). Measured cross sections are in good agreement with the computed ones. A refined assignment of resonances in the proximity of the 4s 1 4p 6 5p resonance was performed. It was concluded that there is a strong influence of the core rearrangement, of the interaction between resonances through the autoionization continua and of the interaction between autoionization continua, on the investigated processes on the basis of the observed good overall agreement between the computed and measured quantities

AcEST: BP917498 [AcEST

Lifescience Database Archive (English)

Full Text Available rome B OS=Nicotiana tabacum GN=PHYB ... 78 2e-21 sp|P33529|PHY_MOUSC Phytochrome OS=Mougeotia scalaris GN=PH...+EG+GLS+ +K++KLMN Sbjct: 1065 GEGLPPELVQDMFHSSRWVTKEGLGLSMCRKILKLMN 1101 >sp|P33529|PHY_MOUSC Phytochrome OS=Mougeotia scala...TVI Chromosome chr12 scaffold_47, whole genom... 73 9e-21 tr|Q3V8G6|Q3V8G6_MOUSC Phytochrome OS=Mougeotia scala

AcEST: DK952008 [AcEST

Lifescience Database Archive (English)

Full Text Available me 1 OS=Physcomitrella patens GN=P... 236 6e-62 sp|P33529|PHY_MOUSC Phytochrome OS=Mougeotia scalaris GN=PHY...>sp|P33529|PHY_MOUSC Phytochrome OS=Mougeotia scalaris GN=PHY PE=2 SV=2 Length = 1124 Score = 216 bits (551)...t) OS=Pinus sylvest... 229 9e-59 tr|Q3V8G6|Q3V8G6_MOUSC Phytochrome OS=Mougeotia scala

Fluid/structure interaction in BERDYNE (Level 4)

International Nuclear Information System (INIS)

Fox, M.J.H.

1988-02-01

A fluid-structure interaction capability has been developed for Level 4 of the finite element dynamics code BERDYNE, as part of the BERSAFE structural analysis system. This permits analysis of small amplitude free or forced vibration of systems comprising elastic structural components and inviscid volumes of possibly compressible fluid. Free fluid surfaces under the influence of gravity may be present. The formulation chosen uses the rigid walled fluid modes, calculated in a preliminary stage, as a basis for description of the coupled system, providing symmetric system matrices for which efficient solution procedures are available. The inclusion of the fluid modal variables within the system matrices is carried out through the use of the BERDYNE 'substructuring' feature, which allows the inclusion of very general 'super-elements' among the normal structural elements. The program also has a seismic analysis capability, used for the analysis of fluid-structure systems subjected to a specified support acceleration time history. In this case analysis is carried out in terms of relative structural motions, but absolute fluid pressures. Application of the BERDYNE fluid/structure interaction capability to some simple test cases produced results in good agreement with results obtained by analytic or independent numerical techniques. Full instructions on the use of the facility will be included in the BERDYNE Level 4 documentation. Interim documentation for the pre-release version is available from the author. (author)

Interactions between the Nse3 and Nse4 components of the SMC5-6 complex identify evolutionarily conserved interactions between MAGE and EID Families.

Directory of Open Access Journals (Sweden)

Jessica J R Hudson

2011-02-01

Full Text Available The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is composed of 6-8 polypeptides, of which Nse1, Nse3 and Nse4 form a tight sub-complex. MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen protein family and Nse4 is related to the EID (E1A-like inhibitor of differentiation family of transcriptional repressors.Using site-directed mutagenesis, protein-protein interaction analyses and molecular modelling, we have identified a conserved hydrophobic surface on the C-terminal domain of Nse3 that interacts with Nse4 and identified residues in its N-terminal domain that are essential for interaction with Nse1. We show that these interactions are conserved in the human orthologs. Furthermore, interaction of MAGEG1, the mammalian ortholog of Nse3, with NSE4b, one of the mammalian orthologs of Nse4, results in transcriptional co-activation of the nuclear receptor, steroidogenic factor 1 (SF1. In an examination of the evolutionary conservation of the Nse3-Nse4 interactions, we find that several MAGE proteins can interact with at least one of the NSE4/EID proteins.We have found that, despite the evolutionary diversification of the MAGE family, the characteristic hydrophobic surface shared by all MAGE proteins from yeast to humans mediates its binding to NSE4/EID proteins. Our work provides new insights into the interactions, evolution and functions of the enigmatic MAGE proteins.

Diversity in Action | Interactive Workshop | 4 July

CERN Multimedia

2013-01-01

Come and take part in an interactive workshop organised by the CERN Diversity Programme designed to creatively explore the meaning of diversity and share your experience of working with differences at CERN.   Thursday 4 July 2013 – 1.30 p.m. - 5.30 p.m. Pump Hall - Building 216-R-401 "Diversity in Action" is an interactive half-day workshop designed to creatively explore the meaning and importance of diversity at CERN, in support of the Organization’s value of “appreciating differences, fostering equality and promoting collaboration”. Using participative multi-media methods, this innovative workshop will provide participants with insights into diversity, help them to develop greater sensitivity to differences, explore ways to recognise and overcome biases and thereby strengthen our tradition of inclusiveness at CERN. Alan Richter, Ph. D., is the president of QED Consulting, a 25-year-old company based in New York. He has consulted to org...

Dipolar and Non-Dipolar Interactions in LiTbF4

DEFF Research Database (Denmark)

Holmes, L. M.; Als-Nielsen, Jens Aage; Guggenheim, H. J.

1975-01-01

The magnetic interactions in LiTbF4 have been studied in measurements of the quasielastic scattering of neutrons from the paramagnetic crystal. Scattering data have been collected at a temperature T=18.6 K, which is 6.5 times the Curie temperature of LiTbF4, and have been least-squares fitted...

Assessing offshore emergency evacuation behavior in a virtual environment using a Bayesian Network approach

International Nuclear Information System (INIS)

Musharraf, Mashrura; Smith, Jennifer; Khan, Faisal; Veitch, Brian; MacKinnon, Scott

2016-01-01

In the performance influencing factor (PIF) hierarchy, person-based influencing factors reside in the top level along with machine-based, team-based, organization-based and situation/stressor-based factors. Though person-based PIFs like morale, motivation, and attitude (MMA) play an important role in shaping performance, it is nearly impossible to assess such PIFs directly. However, it is possible to measure behavioral indicators (e.g. compliance, use of information) that can provide insight regarding the state of the unobservable person-based PIFs. One common approach to measuring these indicators is to carry out a self-reported questionnaire survey. Significant work has been done to make such questionnaires reliable, but the potential validity problem associated with any questionnaire is that the data are subjective and thus may bear a limited relationship to reality. This paper describes the use of a virtual environment to measure behavioral indicators, which in turn can be used as proxies to assess otherwise unobservable PIFs like MMA. A Bayesian Network (BN) model is first developed to define the relationship between person-based PIFs and measurable behavioral indicators. The paper then shows how these indicators can be measured using evidence collected from a virtual environment of an offshore petroleum installation. A study that focused on emergency evacuation scenarios was done with 36 participants. The participants were first assessed using a multiple choice test. They were then assessed based on their observed performance during simulated offshore emergency evacuation conditions. A comparison of the two assessments demonstrates the potential benefits and challenges of using virtual environments to assess behavioral indicators, and thus the person-based PIFs. - Highlights: • New approach to use virtual environment as measure of behavioral indicators. • New model to study morale, motivation, and attitude. • Bayesian Network model to define the

The subfamily-specific interaction between Kv2.1 and Kv6.4 subunits is determined by interactions between the N- and C-termini.

Directory of Open Access Journals (Sweden)

Elke Bocksteins

Full Text Available The "silent" voltage-gated potassium (KvS channel subunit Kv6.4 does not form electrically functional homotetramers at the plasma membrane but assembles with Kv2.1 subunits, generating functional Kv2.1/Kv6.4 heterotetramers. The N-terminal T1 domain determines the subfamily-specific assembly of Kv1-4 subunits by preventing interactions between subunits that belong to different subfamilies. For Kv6.4, yeast-two-hybrid experiments showed an interaction of the Kv6.4 N-terminus with the Kv2.1 N-terminus, but unexpectedly also with the Kv3.1 N-terminus. We confirmed this interaction by Fluorescence Resonance Energy Transfer (FRET and co-immunoprecipitation (co-IP using N-terminal Kv3.1 and Kv6.4 fragments. However, full-length Kv3.1 and Kv6.4 subunits do not form heterotetramers at the plasma membrane. Therefore, additional interactions between the Kv6.4 and Kv2.1 subunits should be important in the Kv2.1/Kv6.4 subfamily-specificity. Using FRET and co-IP approaches with N- and C-terminal fragments we observed that the Kv6.4 C-terminus physically interacts with the Kv2.1 N-terminus but not with the Kv3.1 N-terminus. The N-terminal amino acid sequence CDD which is conserved between Kv2 and KvS subunits appeared to be a key determinant since charge reversals with arginine substitutions abolished the interaction between the N-terminus of Kv2.1 and the C-terminus of both Kv2.1 and Kv6.4. In addition, the Kv6.4(CKv3.1 chimera in which the C-terminus of Kv6.4 was replaced by the corresponding domain of Kv3.1, disrupted the assembly with Kv2.1. These results indicate that the subfamily-specific Kv2.1/Kv6.4 heterotetramerization is determined by interactions between Kv2.1 and Kv6.4 that involve both the N- and C-termini in which the conserved N-terminal CDD sequence plays a key role.

To Determine the Frequency of Bacillus cereus in Powdered Milk Infant Formula Consuming in Neonatal Intensive Care Unit (NICU in Tehran Hospitals in 2013-14

Directory of Open Access Journals (Sweden)

Mohammad Mehdi Soltan Dallal

2017-01-01

Full Text Available Background: In recent years, changing the infant feeding methods and the growing trend of use powdered infant formula (PIF has raised concern about quality and health assessment among them. These products are contaminated with various pathogenic bacteria such as Bacillus cereus which the presence of this bacteria in PIF is important because of consumer age group and virulence of this bacteria in PIF. The aim of this study was to determine the frequency of Bacillus cereus in powdered milk infant formula consuming in neonatal intensive care unit (NICU in Tehran hospitals in 2013-14. Material and Methods: In this cross-sectional study, 125 samples of powdered infant formula milk which were used in Neonatal Intensive Care Unit (NICU were surveyed during 8 month in 2014. Isolation and identification of microorganisms (including Bacillus cereus were carried out according to FDA standard protocol (FDA method on B. cereus selective agar (MYP Agar.   Results: The results of present study showed that of 125 samples from of consumable powdered infant formula milk, 84 (67.2% samples were contaminated with B.cereus and also 18 (14.4% samples were contaminated by more than one B.cereus species. Conclusion: As regards pasteurization process is not effective on the spore of B.cereus., The spores of these bacteria can remain in PIF and can cause food poisoning in infants. For this purpose, more attention to quality control of production units and imported powder milk is recommended in Iranian infant foods.

Two-dimensional electric field measurements in the ionospheric footprint of a flux transfer event

Directory of Open Access Journals (Sweden)

K. A. McWilliams

Full Text Available Line-of-sight Doppler velocities from the SuperDARN CUTLASS HF radar pair have been combined to produce the first two-dimensional vector measurements of the convection pattern throughout the ionospheric footprint of a flux transfer event (a pulsed ionospheric flow, or PIF. Very stable and moderate interplanetary magnetic field conditions, along with a preceding prolonged period of northward interplanetary magnetic field, allow a detailed study of the spatial and the temporal evolution of the ionospheric response to magnetic reconnection. The flux tube footprint is tracked for half an hour across six hours of local time in the auroral zone, from magnetic local noon to dusk. The motion of the footprint of the newly reconnected flux tube is compared with the ionospheric convection velocity. Two primary intervals in the PIF's evolution have been determined. For the first half of its lifetime in the radar field of view the phase speed of the PIF is highly variable and the mean speed is nearly twice the ionospheric convection speed. For the final half of its lifetime the phase velocity becomes much less variable and slows down to the ionospheric convection velocity. The evolution of the flux tube in the magnetosphere has been studied using magnetic field, magnetopause and magnetosheath models. The data are consistent with an interval of azimuthally propagating magnetopause reconnection, in a manner consonant with a peeling of magnetic flux from the magnetopause, followed by an interval of anti-sunward convection of reconnected flux tubes.

Key words: Magnetospheric physics (magnetosphere · ionosphere interactions; plasma convection; solar wind · magnetosphere interactions

Robo4 maintains vessel integrity and inhibits angiogenesis by interacting with UNC5B.

Science.gov (United States)

Koch, Alexander W; Mathivet, Thomas; Larrivée, Bruno; Tong, Raymond K; Kowalski, Joe; Pibouin-Fragner, Laurence; Bouvrée, Karine; Stawicki, Scott; Nicholes, Katrina; Rathore, Nisha; Scales, Suzie J; Luis, Elizabeth; del Toro, Raquel; Freitas, Catarina; Bréant, Christiane; Michaud, Annie; Corvol, Pierre; Thomas, Jean-Léon; Wu, Yan; Peale, Franklin; Watts, Ryan J; Tessier-Lavigne, Marc; Bagri, Anil; Eichmann, Anne

2011-01-18

Robo4 is an endothelial cell-specific member of the Roundabout axon guidance receptor family. To identify Robo4 binding partners, we performed a protein-protein interaction screen with the Robo4 extracellular domain. We find that Robo4 specifically binds to UNC5B, a vascular Netrin receptor, revealing unexpected interactions between two endothelial guidance receptors. We show that Robo4 maintains vessel integrity by activating UNC5B, which inhibits signaling downstream of vascular endothelial growth factor (VEGF). Function-blocking monoclonal antibodies against Robo4 and UNC5B increase angiogenesis and disrupt vessel integrity. Soluble Robo4 protein inhibits VEGF-induced vessel permeability and rescues barrier defects in Robo4(-/-) mice, but not in mice treated with anti-UNC5B. Thus, Robo4-UNC5B signaling maintains vascular integrity by counteracting VEGF signaling in endothelial cells, identifying a novel function of guidance receptor interactions in the vasculature. Copyright © 2011 Elsevier Inc. All rights reserved.

Neutron field characterization and dosimetry at the TRIUMF proton therapy facility

International Nuclear Information System (INIS)

Mukherjee, B.

2002-01-01

Full text: In 1972 the 500 MeV H' Cyclotron of the TRIUMF (Tri University Meson Factory) located in Vancouver, Canada became operational. Beside Meson Physics, high-energy protons of various energy and beam current levels from the TRIUMF Cyclotron are used for scientific research and biomedical applications. Recently, a 500 MeV proton beam from the cyclotron was used as the booster beam for the radioactive ion beam facility, ISAC (Isotope Separator Accelerator) and a second beam as primary irradiation source for the Proton Irradiation Facility (PIF). The major commercial applications of the PIF are the provision of high-energy proton beams for radiation hardness testing of electronic components used in space applications (NASA) and proton therapy of ocular tumors (British Columbia Proton Therapy Facility). The PIF vault was constructed within the main accelerator hall of the TRIUMF using stacks of large concrete blocks. An intense field of fast neutrons is produced during the interaction of high-energy proton beam with target materials, such as, beam stops, collimators and beam energy degraders. The leakage of such neutrons due to insufficient radiological shielding or through the shielding discontinuities may constitute a major share of the personnel radiation exposure of the radiation workers. The neutron energy distribution and dose equivalent near a lead beam stopper bombarded with 116 MeV and 65 MeV collimated proton beams at the Ocular Tumor irradiation facility were evaluated using a Bonner-Sphere Spectrometer and a REM counter respectively. The results were utilized to investigate efficacy of the existing radiological shielding of the PIF. This paper highlights experimental methods to analyze the high-energy accelerator produced neutron beam and basic guideline for the radiological shielding designs of irradiation vault of Proton Therapy facilities

Three-body interactions and the elastic constants of hcp solid 4He

Science.gov (United States)

Barnes, Ashleigh L.; Hinde, Robert J.

2017-09-01

The effect of three-body interactions on the elastic properties of hexagonal close packed solid 4He is investigated using variational path integral (VPI) Monte Carlo simulations. The solid's nonzero elastic constants are calculated, at T = 0 K and for a range of molar volumes from 7.88 cm3/mol to 20.78 cm3/mol, from the bulk modulus and the three pure shear constants C0, C66, and C44. Three-body interactions are accounted for using our recently reported perturbative treatment based on the nonadditive three-body potential of Cencek et al. Previous studies have attempted to account for the effect of three-body interactions on the elastic properties of solid 4He; however, these calculations have treated zero point motions using either the Einstein or Debye approximations, which are insufficient in the molar volume range where solid 4He is characterized as a quantum solid. Our VPI calculations allow for a more accurate treatment of the zero point motions which include atomic correlation. From these calculations, we find that agreement with the experimental bulk modulus is significantly improved when three-body interactions are considered. In addition, three-body interactions result in non-negligible differences in the calculated pure shear constants and nonzero elastic constants, particularly at higher densities, where differences of up to 26.5% are observed when three-body interactions are included. We compare to the available experimental data and find that our results are generally in as good or better agreement with experiment as previous theoretical investigations.

Thermodynamics of lattice QCD with massless quarks and chiral 4-fermion interactions

International Nuclear Information System (INIS)

Kogut, J. B.

1998-01-01

N f = 2 lattice QCD with massless quarks and a weak 4-fermion interaction appears to have the expected second order transition, at least for N t ≥ 6. More work is needed to clarify the N t = 4 case. With more statistics the N t = 6 simulations should produce an accurate determination of the critical exponent β m . Moving to finite mass at β = β c should allow an accurate determination of σ. Hadronic screening masses need further analysis. Other order parameters remain to be analyzed. Unfortunately, there is no obvious way to include 4-fermion interactions with full SU(2) x SU(2) chiral flavor symmetry

Simulation of Different Truncated p16INK4a Forms and In Silico Study of Interaction with Cdk4

Directory of Open Access Journals (Sweden)

Najmeh Fahham

2009-01-01

Full Text Available Protein-protein interactions studies can greatly increase the amount of structural and functional information pertaining to biologically active molecules and processes. The information obtained from such studies can lead to design and application of new modification in order to obtain a desired bioactivity. Many application packages and servers performing docking, such as HEX, DOT, AUTODOCK, and ZDOCK are now available for predicting the lowest free energy state of a protein complex. In this study, we have focused on cyclin-dependent kinase 4 (Cdk4, a key molecule in the regulation of cell cycle progression at the G1-S phase restriction point and p16INK4a, a tumor suppressor which inhibits Cdk4 activity. Truncated structures were created to find the more critical regions of p16 for interaction. The tertiary structures were determined by ProSAL, GENO3D Web Server. We evaluated their interactions with Cdk4 using two docking systems, HEX 4.5 and DOT 1. Calculations were performed on a high-speed computer. Minimizations and visualizations were carried out by PdbViewer 3.7. Considering shape and shape/electrostatic total energy, structures containing ANK II, III and IV motifs that lack the N-terminal region of the full length p16 molecule showed the best fi t complexes among the p16 truncated forms. The free energies were compatible with that of p16 full length original form, the full length. It seems that the N-terminal of the molecule is not crucial for the interaction since the truncated structure containing only this region did not show a good total energy.

It’s good to do good and receive good: The impact of a ‘pay it forward’ style kindness intervention on giver and receiver well-being

OpenAIRE

Pressman, SD; Kraft, TL; Cross, MP

2015-01-01

© 2014 Taylor & Francis. Despite the popularity of the ‘pay it forward’ (PIF) concept in textbooks and popular culture, to date, no study has tested the effectiveness of a brief, one-time PIF activity on the well-being of those who do good and those who receive good. To test this, 83 undergraduates (‘givers’) performed random kind acts for 1.5 h. PIF resulted in a wide range of well-being benefits for givers (e.g. greater positive and lower negative affect), with females showing greater pos...

Interaction of ruthenium (4) and osmium (4) with 2-mercaptobenzimidazole, 2-mercaptobenzoxazole and 2-mercaptobenzothiazole in the presence of edta

International Nuclear Information System (INIS)

Busev, A.I.; Ignat'eva, T.I.; Lomakina, L.N.

1975-01-01

Interaction of ruthenium (4) and osmium (4) with 2-mercaptobenzimidazole (2MBI), 2-mercaptobenzoxazole (2MBO) and 2-mercaptobenzothiazole (2MBT) in the presence of EDTA was studied. The interaction of ruthenium (4) and osmium (4) with EDTA was constidered. Ruthenium complex is formed with constant output at 2-4.5 pH after 30 min.heating. In the lowacid solution (pH 2-4) osmium reacts with EDTA forming soluble compound. Characteristics of ruthenium (4) compound with 2MBI, 2MBO and 2MBT produced in the presence of EDTA are presented. Osmium (4) in the presence of EDTA and above mentioned organic reagents and when heating forms lowsoluble compounds. Possibility of joint determination of ruthenium and osmium with help of 2MBI in the presence of EDTA under conditions of minimum complexing osmium with EDTA was investigated

Interaction of ruthenium (4) and osmium (4) with 2-mercaptobenzimidazole, 2-mercaptobenzoxazole and 2-mercaptobenzothiazole in the presence of EDTA

Energy Technology Data Exchange (ETDEWEB)

Busev, A I; Ignat' eva, T I; Lomakina, L N [Moskovskij Gosudarstvennyj Univ. (USSR). Kafedra Analiticheskoj Khimii

1975-05-01

Interaction of ruthenium (4) and osmium (4) with 2-mercaptobenzimidazole (2MBI), 2-mercaptobenzoxazole (2MBO) and 2-mercaptobenzothiazole (2MBT) in the presence of EDTA was studied. The interaction of ruthenium (4) and osmium (4) with EDTA was considered. Ruthenium complex is formed with constant output at 2-4.5 pH after 30 min. heating. In the low acid solution (pH 2-4) osmium reacts with EDTA forming soluble compound. Characteristics of ruthenium (4) compound with 2MBI, 2MBO and 2MBT produced in the presence of EDTA are presented. Osmium (4) in the presence of EDTA and above mentioned organic reagents and when heating forms low soluble compounds. Possibility of joint determination of ruthenium and osmium with help of 2MBI in the presence of EDTA under conditions of minimum complexing osmium with EDTA was investigated.

Are Sb4n (n>1) clusters weakly interacting tetrahedra?

International Nuclear Information System (INIS)

Kumar, V.

1993-03-01

The electronic and atomic structure of Sb 4 and Sb 8 clusters is studied using the ab-initio molecular dynamics method in the local density approximation. While for Sb 4 we obtain a regular tetrahedron to be about 2.0 eV lower in energy than a bent rhombus, for Sb 8 two structures, (1) two weakly interaction tetrahedra and (2) a bent rhombus interacting with a stretched tetrahedron, obtained from the simulated annealing lie only within about 0.1 eV indicating the importance of the bent rhombus structure for larger clusters. As compared to two isolated tetrahedra, the binding energy of Sb 8 is about 0.5 eV. Our results are thus in excellent agreement with the experimental data which show predominantly the abundance of tetramers above room temperature. (author). 18 refs, 5 figs, 1 tab

Pokemon (FBI-1) interacts with Smad4 to repress TGF-β-induced transcriptional responses.

Science.gov (United States)

Yang, Yutao; Cui, Jiajun; Xue, Feng; Zhang, Chuanfu; Mei, Zhu; Wang, Yue; Bi, Mingjun; Shan, Dapeng; Meredith, Alex; Li, Hui; Xu, Zhi-Qing David

2015-03-01

Pokemon, an important proto-oncoprotein, is a transcriptional repressor that belongs to the POK (POZ and Krüppel) family. Smad4, a key component of TGF-β pathway, plays an essential role in TGF-β-induced transcriptional responses. In this study, we show that Pokemon can interact directly with Smad4 both in vitro and in vivo. Overexpression of Pokemon decreases TGF-β-induced transcriptional activities, whereas knockdown of Pokemon increases these activities. Interestingly, Pokemon does not affect activation of Smad2/3, formation of Smads complex, or DNA binding activity of Smad4. TGF-β1 treatment increases the interaction between Pokemon and Smad4, and also enhances the recruitment of Pokemon to Smad4-DNA complex. In addition, we also find that Pokemon recruits HDAC1 to Smad4 complex but decreases the interaction between Smad4 and p300/CBP. Taken together, all these data suggest that Pokemon is a new partner of Smad4 and plays a negative role in TGF-β pathway. Copyright © 2014. Published by Elsevier B.V.

Structural Basis for Species Selectivity in the HIV-1 gp120-CD4 Interaction: Restoring Affinity to gp120 in Murine CD4 Mimetic Peptides

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Kristin Kassler

2011-01-01

Full Text Available The first step of HIV-1 infection involves interaction between the viral glycoprotein gp120 and the human cellular receptor CD4. Inhibition of the gp120-CD4 interaction represents an attractive strategy to block HIV-1 infection. In an attempt to explore the known lack of affinity of murine CD4 to gp120, we have investigated peptides presenting the putative gp120-binding site of murine CD4 (mCD4. Molecular modeling indicates that mCD4 protein cannot bind gp120 due to steric clashes, while the larger conformational flexibility of mCD4 peptides allows an interaction. This finding is confirmed by experimental binding assays, which also evidenced specificity of the peptide-gp120 interaction. Molecular dynamics simulations indicate that the mCD4-peptide stably interacts with gp120 via an intermolecular β-sheet, while an important salt-bridge formed by a C-terminal lysine is lost. Fixation of the C-terminus by introducing a disulfide bridge between the N- and C-termini of the peptide significantly enhanced the affinity to gp120.

Functional interaction of TRPV4 channel protein with annexin A2 in DRG.

Science.gov (United States)

Ning, Liping; Wang, Chuanwei; Ding, Xinli; Zhang, Yang; Wang, Xuping; Yue, Shouwei

2012-09-01

Transient receptor potential vanilloid 4 (TRPV4) is a Ca(2+)-permeable, non-selective cation channel that is involved in the transmission of pain signals mediated by dorsal root ganglion (DRG). Annexin A2 belongs to a class of membrane-binding proteins that plays an important role in the regulation of ion channels. Nevertheless, little is known about the interaction between them in DRG. In this paper, we evaluated the functional interaction of TRPV4 with annexin A2 in DRG. We have used immunocytochemistry and co-immunoprecipitation assays to investigate the interaction between annexin A2 and TRPV4 in DRG. The role of annexin A2 in the regulation of TRPV4 activity in DRG was further verified by measurement of intracellular free calcium concentrations ([Ca(2+)](i)) and substance P (SP) release. First, annexin A2 was showed partial co-localization with TRPV4 in DRG neurons. Then, annexin A2 and TRPV4 were co-precipitated with each other in DRG lysates. Furthermore, the downregulation of annexin A2 using specific small interfering RNA significantly inhibited Ca(2+) influx and SP mediated by TRPV4. Our results provide evidence that annexin A2 is associated with TRPV4 and regulates TRPV4-mediated Ca(2+) influx and SP release in DRG neurons. The objective of this work is to determine the influence of annexin A2 on TRPV4 in DRG neurons, which may be the basis for treatment of pain relief.

The cachectic mediator proteolysis inducing factor activates NF-kappaB and STAT3 in human Kupffer cells and monocytes

NARCIS (Netherlands)

Watchorn, T.M.; Dowidar, N.; Dejong, C.H.; Waddell, I.D.; Garden, O.J.; Ross, J.A.

2005-01-01

A novel proteoglycan, proteolysis inducing factor (PIF), is capable of inducing muscle proteolysis during the process of cancer cachexia, and of inducing an acute phase response in human hepatocytes. We investigated whether PIF is able to activate pro-inflammatory pathways in human Kupffer cells,

Mass and energy-capital conservation equations to study the price evolution of non-renewable energy resources. Part II-Extension to resources sold to the market

International Nuclear Information System (INIS)

Gori, F.

2006-01-01

The time evolution of the price of resources sold to the market and of the price difference, between sold and extracted resources, is investigated in case of no accumulation of the resources; i.e. when the resources are extracted and sold to the market at the same mass flow rate. The price evolution of sold resources varies with time according to the relation between the price increase factor, PIF, of sold and extracted resources. The price evolutions of sold resources and price difference are investigated according to the relation between extraction rate and interest rate of extracted and sold resources. The price of sold resources and the price difference increase with time if the PIF of sold resources is greater than the PIF of extracted resources and the initial price is greater than the critical price of sold resources, which depends on the initial price of extracted resources and the interest rate of non-extracted and extracted resources. The price of sold resources and the price difference decrease with time if the PIF of sold resources is greater than the PIF of extracted resources and the initial price is smaller than the critical price of sold resources. The other cases are discussed extensively in the paper. (author)

Effective interactions in dilute mixtures of 3He in 4He

International Nuclear Information System (INIS)

Hsu, W.; Pines, D.

1985-01-01

Nonlocal pseudopotentials which describe the effective interaction between 3 He quasiparticles, and between these quasiparticles and the background 4 He liquid, are obtained as a function of concentration and pressure by generalizing the Aldrich--Pines pseudopotentials for pure 3 He and 4 He to dilute mixtures. The hierarchy of physical effects which determine these pseudopotentials is established. Interaction-induced short-range correlations are the dominant physical feature; next in order of importance is the greater zero point motion associated with the replacement of a 4 He atom by a 3 He atom, while spin-duced ''Pauli principle'' correlations play a significantly smaller, albeit still important role. We find a consistent trend in the change of the effective direct quasiparticle interactions with increasing concentration, and show how the Aldrich-Pines pseudopotentials for pure 3 He quasiparticles represent a natural extension of our results for dilute mixtures. Our calculated nonlocal pseudopotential for 3 He quasiparticles is qualitatively similar to that proposed by Bardeen, Baym, and Pines; it changes sign at somewhat lower momentum transfers than the BBP result, varies little with concentration, and provides a physical basis for understanding the BBP result. The effective interaction between quasiparticles of parallel spin, here determined for the first time, is essentially repulsive in the very dilute limit; as the concentration increases, it becomes increasingly attractive at low momentum transfers, and resembles closely that between antiparallel spin quasiparticles at 5% concentration. The concentration-dependent transport properties calculated from these pseudopotentials (which involve only one phenomenological parameter) are in good agreement with experiment at saturated vapor pressure (SVP), 10 atm, and 20 atm

Analysis of fluid-structure interaction and structural respones of Chernobyl-4 reactor

International Nuclear Information System (INIS)

Wang, C.Y.; Pizzica, P.A.; Gvildys, J.; Spencer, B.W.

1989-01-01

The accident at Chernobyl-4 occurred during the running of a test to determine the turbogenerator's ability to provide in-house emergency power after shutting off its steam supply. The accident was the result of a large, destructive power excursion. This paper presents an analysis of the energetic events associated with the fuel failures, fuel-coolant thermal interactions, and the fluid-structure interaction

A new casting defect healing technology

Energy Technology Data Exchange (ETDEWEB)

Hodge, E.S.; Reddoch, T.W. [ForMat Industries, Inc., Knoxville, TN (United States); Viswanathan, S. [Oak Ridge National Lab., TN (United States)

1997-01-01

A new technology is presented for healing of defects in 356 aluminium alloys that provides economic upgrading of these cast alloys. It uses pneumatic isostatic forging (PIF) to produce high quality Al alloys products with enhanced mechanical properties uniform throughout the part, allowing higher design allowables and increased usage of Al alloy castings. The fundamental mechanism underlying PIF is a single mode plastic deformation process that uses isostatic application of pressures for 10-30 seconds at temperature. The process can be integrated in-line with other production operations, i.e., using the latent heat from the previous casting step. Results of applying the PIF process indicate lower cost and significant improvement in mechanical properties that rival and often exceed corresponding properties of other technologies like hot isostatic pressing and related processes. This process offers many advantages that are described in this paper in addition to presenting case histories of property enhancement by PIF and the mechanism responsible for property enhancement.

Observation of femoral and tibial insertion of the posterior cruciate ligament by using conventional CT and transparent 3D-CT

International Nuclear Information System (INIS)

Inoue, Masayuki; Tsukuda, Koichiro; Yasojima, Nobutoshi; Oota, Masahiro; Kasahara, Yasuhiko

2011-01-01

Presented are image data acquisitioned by the volume rendering (VR)-3D-CT and authors' transparent (T)-3D-CT to depict the bone contour, of medial intercondylar ridge (MIR) and posterior intercodylar fossa (PIF) at femoral and tibial insertion, respectively, of the posterior cruciate ligament (PCL) as those data are helpful for planning the reconstruction surgery of PCL and for confirming the femoral PCL insertion by using the C-arm during operation. Helical scanning is conducted with GE MD-CT (64DAS) to reconstruct VR-3D-CT image with the workstation ZIO's ZIO900M Quadra and T-3D-CT image, by reducing the opacity by pixel exclusion of the intraosseous lumen. MIR is observed in all 70 normal knees tested in VR-3D-CT and the bifurcate ridge, in 15 knees among them. In T-3D-CT image, distance data of the origin of MIR from Blumensaat's line and the angle of MIR and bone axis are calculated and presented. In VR-3D-CT and T-3D-CT images of PIF from 20 knees, actual measures of PIF slope angle (degree), PIF area ratio to joint surface (JS) (%), distance from JS to centers of anterolateral (AL) and posterolateral (PM) slopes (mm), and from medial and lateral JS to PIF posterior border (mm), and distance ratios of PM and AL to medial and lateral tibia, respectively, (%) are calculated and presented. Findings are: MIR originates at 45% distal point of Blumensaat's line; the articular line crosses with PIF at its center in T-3D-CT sagittal plane; centers of tibial AL and PM exist at the middle of frontal plane, and at 1.00 and 5.5 mm, respectively, distal points of JS of sagittal plane. The PIF data are rather comparable to those obtained in cadavers reported in 3 literatures and the present procedure is concluded to be valid. (author)

Second-chance forward isomerization dynamics of the red/green cyanobacteriochrome NpR6012g4 from Nostoc punctiforme.

Science.gov (United States)

Kim, Peter W; Freer, Lucy H; Rockwell, Nathan C; Martin, Shelley S; Lagarias, J Clark; Larsen, Delmar S

2012-01-11

The primary ultrafast Z-to-E isomerization photodynamics of the phytochrome-related cyanobacteriochrome NpR6012g4 from Nostoc punctiforme was studied by transient absorption pump-dump-probe spectroscopy. A 2 ps dump pulse resonant with the stimulated emission band depleted 21% of the excited-state population, while the initial photoproduct Lumi-R was depleted by only 11%. We observed a red-shifted ground-state intermediate (GSI) that we assign to a metastable state that failed to isomerize fully. Multicomponent global analysis implicates the generation of additional Lumi-R from the GSI via crossing over the ground-state thermal barrier for full isomerization, explaining the discrepancy between excited-state and Lumi-R depletion by the dump pulse. This second-chance ground-state dynamics provides a plausible explanation for the unusually high quantum yield of 40% for the primary isomerization step in the forward reaction of NpR6012g4. © 2011 American Chemical Society

Gesture and Speech in Interaction - 4th edition (GESPIN 4)

OpenAIRE

Ferré , Gaëlle; Mark , Tutton

2015-01-01

International audience; The fourth edition of Gesture and Speech in Interaction (GESPIN) was held in Nantes, France. With more than 40 papers, these proceedings show just what a flourishing field of enquiry gesture studies continues to be. The keynote speeches of the conference addressed three different aspects of multimodal interaction:gesture and grammar, gesture acquisition, and gesture and social interaction. In a talk entitled Qualitiesof event construal in speech and gesture: Aspect and...

The neuregulin receptor ErbB-4 interacts with PDZ-containing proteins at neuronal synapses

Science.gov (United States)

Garcia, Rolando A. G.; Vasudevan, Kuzhalini; Buonanno, Andres

2000-01-01

Neuregulins regulate the expression of ligand- and voltage-gated channels in neurons and skeletal muscle by the activation of their cognate tyrosine kinase receptors, ErbB 1–4. The subcellular distribution and mechanisms that regulate the localization of ErbB receptors are unknown. We have found that ErbB receptors are present in brain subcellular fractions enriched for postsynaptic densities (PSD). The ErbB-4 receptor is unique among the ErbB proteins because its C-terminal tail (T-V-V) conforms to a sequence that binds to a protein motif known as the PDZ domain. Using the yeast two-hybrid system, we found that the C-terminal region of ErbB-4 interacts with the three related membrane-associated guanylate kinases (MAGUKs) PSD-95/SAP90, PSD-93/chapsyn-110, and SAP 102, which harbor three PDZ domains, as well as with β2-syntrophin, which has a single PDZ domain. As with N-methyl-d-aspartate (NMDA) receptors, ErbB4 interacts with the first two PDZ domains of PSD-95. Using coimmunoprecipitation assays, we confirmed the direct interactions between ErbB-4 and PSD-95 in transfected heterologous cells, as well as in vivo, where both proteins are coimmunoprecipitated from brain lysates. Moreover, evidence for colocalization of these proteins was also observed by immunofluorescence in cultured hippocampal neurons. ErbB-4 colocalizes with PSD-95 and NMDA receptors at a subset of excitatory synapses apposed to synaptophysin-positive presynaptic terminals. The capacity of ErbB receptors to interact with PDZ-domain proteins at cell junctions is conserved from invertebrates to mammals. As discussed, the interactions found between receptor tyrosine kinases and MAGUKs at neuronal synapses may have important implications for activity-dependent plasticity. PMID:10725395

Proton Testing of Advanced Stellar Compass Digital Processing Unit

DEFF Research Database (Denmark)

Thuesen, Gøsta; Denver, Troelz; Jørgensen, Finn E

1999-01-01

The Advanced Stellar Compass Digital Processing Unit was radiation tested with 300 MeV protons at Proton Irradiation Facility (PIF), Paul Scherrer Institute, Switzerland.......The Advanced Stellar Compass Digital Processing Unit was radiation tested with 300 MeV protons at Proton Irradiation Facility (PIF), Paul Scherrer Institute, Switzerland....

X-ray photoelectron investigation of UO2(ClO4)2 interaction with diabase

International Nuclear Information System (INIS)

Teterin, Yu.A.; Nefedov, V.I.; Ivanov, K.E.; Baev, A.S.; Gajpel', G.; Rajkh, T.; Niche, Kh.

1996-01-01

X-ray diffraction study was made on interaction of soluble uranyl perchlorate with diabase, composing rocks in regions of Chelyabinsk and Chernobyl accidents and in places of radioactive waste burials. Absence of ClO 4 - anion in analyzed products of UO 2 (ClO 4 ) 2 interaction with diabase testifies to the absence of physio- or chemosorbed UO 2 (ClO 4 ) 2 layer on its surface. Formation of uranyl compounds (uranyl hydroxides) on diabase surface was confirmed, and bond lengths for these compounds were determined. Reaction of substitution of uranium ions for calcium ions proceeds more actively in the surface layers of diabase grains. 4 refs.; 3 tabs

Development and construction of a specific chamber for phototoxicity test

Energy Technology Data Exchange (ETDEWEB)

Sufi, Bianca S.; Mathor, Monica B., E-mail: biancasufi@usp.br, E-mail: mathor@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Esteves-Pedro, Natalia M.; Kaneko, Telma Mary, E-mail: nataliamenves@yahoo.com.br, E-mail: tsakuda@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Fac. de Ciencias Farmaceuticas; Lopes, Patricia, E-mail: patricia.lopes@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil)

2013-07-01

Phototoxicity corresponds to the acute toxic response induced after skin exposure 'in vivo' and 'ex vivo' to certain chemicals and subsequent exposure to irradiation. Phototoxicity 'in vitro' assay is determined by viability of fibroblasts BALB/c 3T3 exposed to chemicals in the presence and absence of light. Substances identified as phototoxic are susceptible to 'in vivo' phototoxicity (OECD 432, 2004). A chamber was developed and constructed according to the guidelines OECD Toxicity Guide - 432 and ®ECVAM DB-ALM: INVITTOX N. 78. The chamber was built in stainless steel frame, with UVA lamps and dark area for negative control. The tests to qualify the chamber were performed with Sodium Lauryl Sulfate, recommended by the guides aforementioned, as negative control; and Bergamot oil (Givaudan-Roche), as positive control. Bergamot, Citrus bergamia, has, as major component, Bergapten responsible for its photosensitive activity. Both samples were diluted in Phosphate Buffered Saline with concentrations between 0.005 and 0.1 mg/mL, which were calculated by the dilution factor 1.47. These tests were performed over fibroblast BALB/c 3T3 culture and submitted to phototoxicity assay with MTS dye, under spectrophotometric reading, which allows determining the Photo Irritation Factor (PIF), what suggests that a substance with a PIF<2 predicts no phototoxicity; PIF>2 and <5 provides likely phototoxicity and PIF>5 provides phototoxicity. Sodium Lauryl Sulfate presented a PIF=1, being in accordance with the OECD. Bergamot oil has shown to be likely phototoxic with a PIF=2,475. These results provide that the chamber is qualified to be used to perform phototoxicity tests with assurance and security. (author)

Solution structure of a syndecan-4 cytoplasmic domain and its interaction with phosphatidylinositol 4,5-bisphosphate

DEFF Research Database (Denmark)

Lee, D; Oh, E S; Woods, A

1998-01-01

Syndecan-4, a transmembrane heparan sulfate proteoglycan, is a coreceptor with integrins in cell adhesion. It has been suggested to form a ternary signaling complex with protein kinase Calpha and phosphatidylinositol 4,5-bisphosphate (PIP2). Syndecans each have a unique, central, and variable (V......) region in their cytoplasmic domains, and that of syndecan-4 is critical to its interaction with protein kinase C and PIP2. Two oligopeptides corresponding to the variable region (4V) and whole domain (4L) of syndecan-4 cytoplasmic domain were synthesized for nuclear magnetic resonance (NMR) studies. Data...... and dynamical simulated annealing calculations. The 4V peptide in the presence of PIP2 formed a compact dimer with two twisted strands packed parallel to each other and the exposed surface of the dimer consisted of highly charged and polar residues. The overall three-dimensional structure in solution exhibits...

S100A4 interacts with p53 in the nucleus and promotes p53 degradation.

Science.gov (United States)

Orre, L M; Panizza, E; Kaminskyy, V O; Vernet, E; Gräslund, T; Zhivotovsky, B; Lehtiö, J

2013-12-05

S100A4 is a small calcium-binding protein that is commonly overexpressed in a range of different tumor types, and it is widely accepted that S100A4 has an important role in the process of cancer metastasis. In vitro binding assays has shown that S100A4 interacts with the tumor suppressor protein p53, indicating that S100A4 may have additional roles in tumor development. In the present study, we show that endogenous S100A4 and p53 interact in complex samples, and that the interaction increases after inhibition of MDM2-dependent p53 degradation using Nutlin-3A. Further, using proximity ligation assay, we show that the interaction takes place in the cell nucleus. S100A4 knockdown experiments in two p53 wild-type cell lines, A549 and HeLa, resulted in stabilization of p53 protein, indicating that S100A4 is promoting p53 degradation. Finally, we demonstrate that S100A4 knockdown leads to p53-dependent cell cycle arrest and increased cisplatin-induced apoptosis. Thus, our data add a new layer to the oncogenic properties of S100A4 through its inhibition of p53-dependent processes.

Effect of electrostatic interaction on thermochemical behavior of 12-crown-4 ether in various polar solvents

International Nuclear Information System (INIS)

Barannikov, Vladimir P.; Guseynov, Sabir S.; Vyugin, Anatoliy I.

2010-01-01

The enthalpies of solution of 12-crown-4 ether have been measured in chloroform, ethyl acetate, acetone, pyridine, acetonitrile and methanol at 298.15 K. The values of enthalpy of solvation and solute-solvent interaction were determined from the obtained results and similar literature data for 12-crown-4 in solvents of various polarities. It was shown that the certain correlation is observed between the enthalpy of solute-solvent interaction and the squared dipole moment of the solvent molecules for solutions in tetrachlormethane, ethyl acetate, pyridine, acetonitrile, DMF, DMSO and propylene carbonate. This means that the electrostatic interaction of 12-crown-4 with polar solvent molecules contributes significantly to the exothermic effect of solvation. The understated negative value was found for the enthalpy of interaction of 12-crown-4 with acetone that can be connected with domination of low polar conformer of the crown ether in acetone medium. The most negative values of enthalpy of solvation are observed for solutions in chloroform and water because of hydrogen bonding between O-atoms of crown ether and molecules of the indicated solvents. This effect is not observed for methanol. The negative coefficient of pairwise solute-solute interaction in methanol indicates that the effects of solvophobic solute-solute interaction and H-bonding of the ether molecule with chain associates of methanol are not evinced in the thermochemical behavior of 12-crown-4.

Mid-infrared picosecond pump-dump-probe and pump-repump-probe experiments to resolve a ground-state intermediate in cyanobacterial phytochrome Cph1.

Science.gov (United States)

van Wilderen, Luuk J G W; Clark, Ian P; Towrie, Michael; van Thor, Jasper J

2009-12-24

Multipulse picosecond mid-infrared spectroscopy has been used to study photochemical reactions of the cyanobacterial phytochrome photoreceptor Cph1. Different photophysical schemes have been discussed in the literature to describe the pathways after photoexcitation, particularly, to identify reaction phases that are linked to photoisomerisation and electronic decay in the 1566-1772 cm(-1) region that probes C=C and C=O stretching modes of the tetrapyrrole chromophore. Here, multipulse spectroscopy is employed, where, compared to conventional visible pump-mid-infrared probe spectroscopy, an additional visible pulse is incorporated that interacts with populations that are evolving on the excited- and ground-state potential energy surfaces. The time delays between the pump and the dump pulse are chosen such that the dump pulse interacts with different phases in the reaction process. The pump and dump pulses are at the same wavelength, 640 nm, and are resonant with the Pr ground state as well as with the excited state and intermediates. Because the dump pulse additionally pumps the remaining, partially recovered, and partially oriented ground-state population, theory is developed for estimating the fraction of excited-state molecules. The calculations take into account the model-dependent ground-state recovery fraction, the angular dependence of the population transfer resulting from the finite bleach that occurs with linearly polarized intense femtosecond optical excitation, and the partially oriented population for the dump field. Distinct differences between the results from the experiments that use a 1 or a 14 ps dump time favor a branching evolution from S1 to an excited state or reconfigured chromophore and to a newly identified ground-state intermediate (GSI). Optical dumping at 1 ps shows the instantaneous induced absorption of a delocalized C=C stretching mode at 1608 cm(-1), where the increased cross section is associated with the electronic ground

APOE-ε4 Allele Altered the Rest-Stimulus Interactions in Healthy Middle-Aged Adults.

Directory of Open Access Journals (Sweden)

Feng-Xian Yan

Full Text Available The apolipoprotein E-ε4 allele is a well-known genetic risk factor for late-onset Alzheimer's disease, which also impacts the cognitive functions and brain network connectivity in healthy middle-aged adults without dementia. Previous studies mainly focused on the effects of apolipoprotein E-ε4 allele on single index using task or resting-state fMRI. However, how these evoked and spontaneous BOLD indices interact with each other remains largely unknown. Therefore, we evaluated the 'rest-stimulus interaction' between working-memory activation and resting-state connectivity in middle-aged apolipoprotein E-ε4 carriers (n=9 and non-carriers (n=8. Four n-back task scans (n = 0, 1, 2, 3 and one resting-state scan were acquired at a 3T clinical MRI scanner. The working-memory beta maps of low-, moderate-, and high-memory loads and resting-state connectivity maps of default mode, executive control, and hippocampal networks were derived and compared between groups. Apolipoprotein E-ε4 carriers presented declined working-memory activation in the high-memory load across whole brain regions and reduced hippocampal connectivity compared with non-carriers. In addition, disrupted rest-stimulus interactions were found in the right anterior insula and bilateral parahippocampal regions for middle-aged adults with apolipoprotein E-ε4 allele. The rest-stimulus interaction improved the detectability of network integrity changes in apolipoprotein E-ε4 carriers, demonstrating the disrupted intrinsic connectivity within the executive-functional regions and the modulated memory-encoding capability within hippocampus-related regions.

Reference values of inspiratory spirometry for Finnish adults.

Science.gov (United States)

Kainu, Annette; Timonen, Kirsi L; Vanninen, Esko; Sovijärvi, Anssi R

2018-03-07

Inspiratory spirometry is used in evaluation of upper airway disorders e.g. fixed or variable obstruction. There are, however, very few published data on normal values for inspiratory spirometry. The main aim of this study was to produce reference values for inspiratory spirometry for healthy Finnish adults. Inspiratory spirometry was preplanned to a sample of the Finnish spirometry reference values sample. Data was successfully retrieved from 368 healthy nonsmoking adults (132 males) between 19 and 83 years of age. Reference equations were produced for forced inspiratory vital capacity (FIVC), forced inspiratory volume in one second (FIV1), FIV1/FIVC, peak inspiratory flow (PIF) and the ratios of FIV1/forced expiratory volume in one second and PIF/peak expiratory flow. The present values were compared to PIF values from previously used Finnish study of Viljanen et al. (1982) reference values and Norwegian values for FIV1, FIVC and FIV1/FIVC presented by Gulsvik et al. (2001). The predicted values from the Gulsvik et al. (2001), provided a good fit for FIVC, but smaller values for FIV1 with mean 108.3 and 109.1% of predicted values for males and females, respectively. PIF values were 87.4 and 91.2% of Viljanen et al. (1982) predicted values in males and females, respectively. Differences in measurement methods and selection of results may contribute to the observed differences. Inspiratory spirometry is technically more demanding and needs repeatability criteria to improve validity. New reference values are suggested to clinical use in Finland when assessing inspiratory spirometry. Utility of inspiratory to expiratory values indices in assessment of airway collapse need further study.

An Oct4-Centered Protein Interaction Network in Embryonic Stem Cells

NARCIS (Netherlands)

D.L.C. van den Berg (Debbie); T. Snoek (Tim); N.P. Mullin (Nick); A. Yates (Adam); K. Bezstarosti (Karel); J.A.A. Demmers (Jeroen); I. Chambers (Ian); R.A. Poot (Raymond)

2010-01-01

textabstractTranscription factors, such as Oct4, are critical for establishing and maintaining pluripotent cell identity. Whereas the genomic locations of several pluripotency transcription factors have been reported, the spectrum of their interaction partners is underexplored. Here, we use an

Interaction mechanisms of ionic liquids [Cnmim]Br (n=4, 6, 8, 10) with bovine serum albumin

International Nuclear Information System (INIS)

Yan Hua; Wu Junyong; Dai Guoliang; Zhong Aiguo; Chen Hao; Yang Jianguo; Han Deman

2012-01-01

It is important to study the interaction of ionic liquids (ILs) with protein for the applications of ILs in biochemical process, and help the researchers to choose and design the better ILs to serve as a solvent. In this work, the interaction between 1-alkyl-3-methylimidazolium bromide [C n mim]Br (n=4, 6, 8, 10) and bovine serum albumin (BSA) was systematically investigated for the first time by multi-spectroscopic approach (fluorescence, UV–vis and FT-IR spectroscopy) and density functional theory (DFT). [C n mim]Br (n=4, 6, 8, 10) can bind to BSA by H-bond interaction between their cationic headgroups and Asp/Glu amino acid residue at the surface of BSA, and hydrophobic interaction between their hydrocarbon chains and the hydrophobic amino acid residues in the interior of BSA. On the basis of thermodynamic parameters and the similar structure of [C n mim]Br (n=4, 6, 8, 10), it can be inferred that the hydrophobic interaction plays a major role in the interaction of [C 10 mim]Br with BSA, while the hydrogen bond and van der Waals force play a major role in the interaction of [C n mim]Br (n=4, 6, 8) with BSA. Synchronous fluorescence and FT-IR spectra indicate that [C 10 mim]Br could markedly change the secondary structure of BSA, while [C n mim]Br (n=4, 6, 8) could slightly change the secondary structure of BSA. The results allowed us to understand (i) the effect of the alkyl chain length of the cation on the mechanism of ILs–protein interaction and (ii) the effect of the alkyl chain length of the cation on the protein secondary structure. - Highlights: ► Interaction of [C n mim]Br with BSA was investigated by spectroscopy and DFT. ► Interaction mechanisms and BSA secondary structure were discussed. ► Effects of the alkyl chain length of cation were presented.

New insights into circulating FABP4: Interaction with cytokeratin 1 on endothelial cell membranes.

Science.gov (United States)

Saavedra, Paula; Girona, Josefa; Bosquet, Alba; Guaita, Sandra; Canela, Núria; Aragonès, Gemma; Heras, Mercedes; Masana, Lluís

2015-11-01

Fatty acid-binding protein 4 (FABP4) is an adipose tissue-secreted adipokine that is involved in the regulation of energetic metabolism and inflammation. Increased levels of circulating FABP4 have been detected in individuals with cardiovascular risk factors. Recent studies have demonstrated that FABP4 has a direct effect on peripheral tissues, specifically promoting vascular dysfunction; however, its mechanism of action is unknown. The objective of this work was to assess the specific interactions between exogenous FABP4 and the plasma membranes of endothelial cells. Immunofluorescence assays showed that exogenous FABP4 localized along the plasma membranes of human umbilical vein endothelial cells (HUVECs), interacting specifically with plasma membrane proteins. Anti-FABP4 immunoblotting revealed two covalent protein complexes containing FABP4 and its putative receptor; these complexes were approximately 108 kDa and 77 kDa in size. Proteomics and mass spectrometry experiments revealed that cytokeratin 1 (CK1) was the FABP4-binding protein. An anti-CK1 immunoblot confirmed the presence of CK1. FABP4-CK1 complexes were also detected in HAECs, HCASMCs, HepG2 cells and THP-1 cells. Pharmacological FABP4 inhibition by BMS309403 results in a slight decrease in the formation of these complexes, indicating that fatty acids may play a role in FABP4 functionality. In addition, we demonstrated that exogenous FABP4 crosses the plasma membrane to enter the cytoplasm and nucleus in HUVECs. These findings indicate that exogenous FABP4 interacts with plasma membrane proteins, specifically CK1. These data contribute to our current knowledge regarding the mechanism of action of circulating FABP4.

Professional identity formation: creating a longitudinal framework through TIME (Transformation in Medical Education).

Science.gov (United States)

Holden, Mark D; Buck, Era; Luk, John; Ambriz, Frank; Boisaubin, Eugene V; Clark, Mark A; Mihalic, Angela P; Sadler, John Z; Sapire, Kenneth J; Spike, Jeffrey P; Vince, Alan; Dalrymple, John L

2015-06-01

The University of Texas System established the Transformation in Medical Education (TIME) initiative to reconfigure and shorten medical education from college matriculation through medical school graduation. One of the key changes proposed as part of the TIME initiative was to begin emphasizing professional identity formation (PIF) at the premedical level. The TIME Steering Committee appointed an interdisciplinary task force to explore the fundamentals of PIF and to formulate strategies that would help students develop their professional identity as they transform into physicians. In this article, the authors describe the task force's process for defining PIF and developing a framework, which includes 10 key aspects, 6 domains, and 30 subdomains to characterize the complexity of physician identity. The task force mapped this framework onto three developmental phases of medical education typified by the undergraduate student, the clerkship-level medical student, and the graduating medical student. The task force provided strategies for the promotion and assessment of PIF for each subdomain at each of the three phases, in addition to references and resources. Assessments were suggested for student feedback, curriculum evaluation, and theoretical development. The authors emphasize the importance of longitudinal, formative assessment using a combination of existing assessment methods. Though not unique to the medical profession, PIF is critical to the practice of exemplary medicine and the well-being of patients and physicians.

Fluid Structure Interaction Analysis in Manufacturing Metal/Polymer Macro-Composites

International Nuclear Information System (INIS)

Baesso, R.; Lucchetta, G.

2007-01-01

Polymer Injection Forming (PIF) is a new manufacturing technology for sheet metal-polymer macro-composites, which results from the combination of injection moulding and sheet metal forming. This process consists on forming the sheet metal according to the boundary of the mould cavity by means of the injected polymer. After cooling, the polymer bonds permanently to the metal resulting in a sheet metal-polymer macro-composite product. Comparing this process to traditional ones (where the polymeric and metal parts are joined together after separate forming) the main advantages are both reduction of production costs and increase of part quality. This paper presents a multi-physics numerical simulation of the process performed in the Ansys/CFX environment

Model calculations of the interaction of two parallel antiaromatic 4n π-electron systems

Science.gov (United States)

Böhm, Michael C.; Bickert, Peter; Hafner, Klaus; Boekelheide, V.

1984-01-01

The nature of the interaction between decks of a pentalene dimer and an s-indacene dimer has been studied by semi-empirical MNDO/1 and MINDO/3 calculations for distances between decks of from 5 Å to 2 Å. In contradiction to qualitative predictions from a frontier orbital analysis, it is found that the 4n-4n π-electron interaction between decks for such dimers is destabilizing for distances exceeding about 2.5 Å. PMID:16593458

Incorporating Partners in Flight Priorities into State Agency Operational Plans: Development of a Management System for Wetland Passerines

Science.gov (United States)

Thomas P. Hodgman

2005-01-01

State agencies are often considered the prime avenues for implementation of Partners in Flight (PIF) bird conservation plans. Yet, such agencies already have in place a planning structure, which allows for dispersal of Federal Aid funds and guides management actions. Consequently, superimposing additional planning frameworks (e.g., PIF bird conservation plans) on state...

Antiproton interaction with 4He as a test of GUT cosmology

International Nuclear Information System (INIS)

Chechetkin, V.M.; Khlopov, M.Yu.; Zeldovich, Ya.B.

1982-01-01

A new possibility of checking some GUT models is suggested, basing on the analysis of their cosmological consequences and the experimental study of the anti p 4 He interaction. The study of annihilation of antiprotons with 4 He may provide limits on the possible amount of antimatter in the early Universe, limits on the probability of formation of primordial black holes and restrictions on the GUT parameters determining the properties of domains of antimatter

Interactions between Bmp-4 and Msx-1 act to restrict gene expression to odontogenic mesenchyme.

Science.gov (United States)

Tucker, A S; Al Khamis, A; Sharpe, P T

1998-08-01

Tooth development is regulated by a reciprocal series of epithelial-mesenchymal interactions. Bmp4 has been identified as a candidate signalling molecule in these interactions, initially as an epithelial signal and then later at the bud stage as a mesenchymal signal (Vainio et al. [1993] Cell 75:45-58). A target gene for Bmp4 signalling is the homeobox gene Msx-1, identified by the ability of recombinant Bmp4 protein to induce expression in mesenchyme. There is, however, no evidence that Bmp4 is the endogenous inducer of Msx-1 expression. Msx-1 and Bmp-4 show dynamic, interactive patterns of expression in oral epithelium and ectomesenchyme during the early stages of tooth development. In this study, we compare the temporal and spatial expression of these two genes to determine whether the changing expression patterns of these genes are consistent with interactions between the two molecules. We show that changes in Bmp-4 expression precede changes in Msx-1 expression. At embryonic day (E)10.5-E11.0, expression patterns are consistent with BMP4 from the epithelium, inducing or maintaining Msx-1 in underlying mesenchyme. At E11.5, Bmp-4 expression shifts from epithelium to mesenchyme and is rapidly followed by localised up-regulation of Msx-1 expression at the sites of Bmp-4 expression. Using cultured explants of developing mandibles, we confirm that exogenous BMP4 is capable of replacing the endogenous source in epithelium and inducing Msx-1 gene expression in mesenchyme. By using noggin, a BMP inhibitor, we show that endogenous Msx-1 expression can be inhibited at E10.5 and E11.5, providing the first evidence that endogenous Bmp-4 from the epithelium is responsible for regulating the early spatial expression of Msx-1. We also show that the mesenchymal shift in Bmp-4 is responsible for up-regulating Msx-1 specifically at the sites of future tooth formation. Thus, we establish that a reciprocal series of interactions act to restrict expression of both genes to future

Relations between Automatically Extracted Motion Features and the Quality of Mother-Infant Interactions at 4 and 13 Months.

Science.gov (United States)

Egmose, Ida; Varni, Giovanna; Cordes, Katharina; Smith-Nielsen, Johanne; Væver, Mette S; Køppe, Simo; Cohen, David; Chetouani, Mohamed

2017-01-01

Bodily movements are an essential component of social interactions. However, the role of movement in early mother-infant interaction has received little attention in the research literature. The aim of the present study was to investigate the relationship between automatically extracted motion features and interaction quality in mother-infant interactions at 4 and 13 months. The sample consisted of 19 mother-infant dyads at 4 months and 33 mother-infant dyads at 13 months. The coding system Coding Interactive Behavior (CIB) was used for rating the quality of the interactions. Kinetic energy of upper-body, arms and head motion was calculated and used as segmentation in order to extract coarse- and fine-grained motion features. Spearman correlations were conducted between the composites derived from the CIB and the coarse- and fine-grained motion features. At both 4 and 13 months, longer durations of maternal arm motion and infant upper-body motion were associated with more aversive interactions, i.e., more parent-led interactions and more infant negativity. Further, at 4 months, the amount of motion silence was related to more adaptive interactions, i.e., more sensitive and child-led interactions. Analyses of the fine-grained motion features showed that if the mother coordinates her head movements with her infant's head movements, the interaction is rated as more adaptive in terms of less infant negativity and less dyadic negative states. We found more and stronger correlations between the motion features and the interaction qualities at 4 compared to 13 months. These results highlight that motion features are related to the quality of mother-infant interactions. Factors such as infant age and interaction set-up are likely to modify the meaning and importance of different motion features.

Interaction of 2,4,6-trichlorophenol with high carbon iron filings: Reaction and sorption mechanisms

Energy Technology Data Exchange (ETDEWEB)

Sinha, Alok [Environmental Engineering and Management Programme, Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Bose, Purnendu [Environmental Engineering and Management Programme, Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)], E-mail: pbose@iitk.ac.in

2009-05-15

Reductive dehalogenation of 2,4,6-trichlorophenol (2,4,6-TCP) by two types of high carbon iron filings (HCIF), HCIF-1 and HCIF-2 was studied in batch reactors. While the iron, copper, manganese and carbon content of the two types of HCIF was similar, the specific surface area of HCIF-1 and HCIF-2 were 1.944 and 3.418 m{sup 2} g{sup -1}, respectively. During interaction with HCIF-1, 2,4,6-TCP adsorbed on HCIF-1 surface resulting in rapid reduction of aqueous phase 2,4,6-TCP concentration. However, reductive dehalogenation of 2,4,6-TCP was negligible. During interaction between 2,4,6-TCP and HCIF-2, both 2,4,6-TCP adsorption on HCIF-2, and 2,4,6,-TCP dechlorination was observed. 2,4,6-TCP partitioning between solid and aqueous phase could be described by a Freundlich isotherm, while 2,4,6-TCP dechlorination could be described by an appropriate rate expression. A mathematical model was developed for describing the overall interaction of 2,4,6-TCP with HCIF-2, incorporating simultaneous adsorption/desorption and dechlorination reactions of 2,4,6-TCP with the HCIF surface. 2,4-Dichlorophenol (2,4-DCP), 2-chlorophenol (2-CP) and minor amounts of 4-chlorophenol (4-CP) evolved as 2,4,6-TCP dechlorination by-products. The evolved 2,4-DCP partitioned strongly to the HCIF surface. 4-CP and 2-CP accumulated in the aqueous phase. No transformation of 2-CP or 4-CP to phenol was observed.

PDS Label Assistant for Interactive Design (PLAID): Simplifying PDS4 Label Template Building

Science.gov (United States)

Algermissen, S. S.; Padams, J. H.; Radulescu, C.

2017-06-01

The PDS Label Assistant for Interactive Design (PLAID) tool seeks to simplify and expedite the process of building a PDS4 label template with a simple step-by-step interface that does not require experience with XML or PDS4 Schemas and Schematrons.

REPORT OF THE AOU CONSERVATION COMMITTEE ON THE PARTNERS IN FLIGHT SPECIES PRIORITIZATION PLAN

Science.gov (United States)

STEVEN R. J. BEISSINGER; MICHAEL REED; JR. WUNDERLE; DEBORAH M. FINCH

2000-01-01

Partners in Flight (PIF) is a coalition of federal, state, and local government agencies; nongovernmental organizations (NGOs); philanthropic foundations; and industry that is working to conserve the birds of the Western Hemisphere. PIF was launched in 1990 in response to growing concerns about declines in the populations of many landbirds, and to spearhead the...

A long-range attractive interaction of rotons in superfluid 4He

International Nuclear Information System (INIS)

Nishiyama, Toshiyuki; Sai, Shunkichi

1974-01-01

With the use of the method of the collective description developed by one of the authors (N) for superfluid 4 He, it is shown that a long-range interaction of rotons transmitted by phonons is attractive and yields a resonance state of a roton pair with the binding energy of the order of magnitude 0.12 K which is relevant to the recent experimental results of the Raman scattering. The effect of the short-range mutual interaction of rotons is also discussed. Some comments on the relationship to the other theories of the collective description are made in appendices. (author)

Interaction of adsorption of reactive yellow 4 from aqueous solutions onto synthesized calcium phosphate

Directory of Open Access Journals (Sweden)

H. El Boujaady

2017-01-01

Full Text Available The interaction of reactive yellow 4 with Apatitic Tricalcium Phosphate (PTCa has been investigated in aqueous medium to understand the mechanism of adsorption and explore the potentiality of this phosphate toward controlling pollution resulting from textile dyes. Transmission electron microscopy (TEM analysis demonstrates that the adsorbent is composed of needle-like nanoparticles and the SAED pattern exhibits spotted sharp and continuous rings that evidence polycrystalline grains. X-ray diffraction results showed that, the crystallinity of the dye decreased after interaction with RY4 indicatating incorporation of the dye into the micropores and macropores of the adsorbent. The results of Fourier transform infrared (FTIR spectroscopy indicate that the adsorption is due to the electrostatic interaction between the –SO3- groups of dye and the surface of the Phosphate. The desorption efficiency was very high at about 99.4%. The presence of calcium ions favored the adsorption of the dye, while the phosphate ions inhibited it.

Cognitive modeling and dynamic probabilistic simulation of operating crew response to complex system accidents. Part 2: IDAC performance influencing factors model

International Nuclear Information System (INIS)

Chang, Y.H.J.; Mosleh, A.

2007-01-01

This is the second in a series of five papers describing the information, decision, and action in crew context (IDAC) model for human reliability analysis. An example application of this modeling technique is also discussed in this series. The model is developed to probabilistically predict the responses of the nuclear power plant control room operating crew in accident conditions. The operator response spectrum includes cognitive, psychological, and physical activities during the course of an accident. This paper identifies the IDAC set of performance influencing factors (PIFs), providing their definitions and causal organization in the form of a modular influence diagram. Fifty PIFs are identified to support the IDAC model to be implemented in a computer simulation environment. They are classified into eleven hierarchically structured groups. The PIFs within each group are independent to each other; however, dependencies may exist between PIFs within different groups. The supporting evidence for the selection and organization of the influence paths based on psychological literature, observations, and various human reliability analysis methodologies is also indicated

Complementary responses to mean and variance modulations in the perfect integrate-and-fire model.

Science.gov (United States)

Pressley, Joanna; Troyer, Todd W

2009-07-01

In the perfect integrate-and-fire model (PIF), the membrane voltage is proportional to the integral of the input current since the time of the previous spike. It has been shown that the firing rate within a noise free ensemble of PIF neurons responds instantaneously to dynamic changes in the input current, whereas in the presence of white noise, model neurons preferentially pass low frequency modulations of the mean current. Here, we prove that when the input variance is perturbed while holding the mean current constant, the PIF responds preferentially to high frequency modulations. Moreover, the linear filters for mean and variance modulations are complementary, adding exactly to one. Since changes in the rate of Poisson distributed inputs lead to proportional changes in the mean and variance, these results imply that an ensemble of PIF neurons transmits a perfect replica of the time-varying input rate for Poisson distributed input. A more general argument shows that this property holds for any signal leading to proportional changes in the mean and variance of the input current.

High-throughput exposure modeling to support prioritization of chemicals in personal care products

DEFF Research Database (Denmark)

Csiszar, Susan A.; Ernstoff, Alexi; Fantke, Peter

2016-01-01

-on and wash-off products which had median PiFs of 0.5 and 0.02 across the 518 chemicals, respectively. The PiF is a function of product characteristics and physico-chemical properties and is maximized when skin permeability is high and volatility is low such that there is no competition between skin and air...

Interactions between urinary 4-tert-octylphenol levels and metabolism enzyme gene variants on idiopathic male infertility.

Directory of Open Access Journals (Sweden)

Yufeng Qin

Full Text Available Octylphenol (OP and Trichlorophenol (TCP act as endocrine disruptors and have effects on male reproductive function. We studied the interactions between 4-tert-Octylphenol (4-t-OP, 4-n- Octylphenol (4-n-OP, 2,3,4-Trichlorophenol (2,3,4-TCP, 2,4,5-Trichlorophenol (2,4,5-TCP urinary exposure levels and polymorphisms in selected xenobiotic metabolism enzyme genes among 589 idiopathic male infertile patients and 396 controls in a Han-Chinese population. Ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS was used to measure alkylphenols and chlorophenols in urine. Polymorphisms were genotyped using the SNPstream platform and the Taqman method. Among four phenols that were detected, we found that only exposure to 4-t-OP increased the risk of male infertility (P(trend = 1.70×10(-7. The strongest interaction was between 4-t-OP and rs4918758 in CYP2C9 (P(inter = 6.05×10(-7. It presented a significant monotonic increase in risk estimates for male infertility with increasing 4-t-OP exposure levels among men with TC/CC genotype (low level compared with non-exposed, odds ratio (OR = 2.26, 95% confidence intervals (CI = 1.06, 4.83; high level compared with non-exposed, OR = 9.22, 95% CI = 2.78, 30.59, but no associations observed among men with TT genotype. We also found interactions between 4-t-OP and rs4986894 in CYP2C19, and between rs1048943 in CYP1A1, on male infertile risk (P(inter = 8.09×10(-7, P(inter = 3.73×10(-4, respectively.We observed notable interactions between 4-t-OP exposure and metabolism enzyme gene polymorphisms on idiopathic infertility in Han-Chinese men.

Modeling the intermolecular interactions: molecular structure of N-3-hydroxyphenyl-4-methoxybenzamide.

Science.gov (United States)

Karabulut, Sedat; Namli, Hilmi; Kurtaran, Raif; Yildirim, Leyla Tatar; Leszczynski, Jerzy

2014-03-01

The title compound, N-3-hydroxyphenyl-4-methoxybenzamide (3) was prepared by the acylation reaction of 3-aminophenol (1) and 4-metoxybenzoylchloride (2) in THF and characterized by ¹H NMR, ¹³C NMR and elemental analysis. Molecular structure of the crystal was determined by single crystal X-ray diffraction and DFT calculations. 3 crystallizes in monoclinic P2₁/c space group. The influence of intermolecular interactions (dimerization and crystal packing) on molecular geometry has been evaluated by calculations performed for three different models; monomer (3), dimer (4) and dimer with added unit cell contacts (5). Molecular structure of 3, 4 and 5 was optimized by applying B3LYP method with 6-31G+(d,p) basis set in gas phase and compared with X-ray crystallographic data including bond lengths, bond angles and selected dihedral angles. It has been concluded that although the crystal packing and dimerization have a minor effect on bond lengths and angles, however, these interactions are important for the dihedral angles and the rotational conformation of aromatic rings. Copyright © 2013 Elsevier Inc. All rights reserved.

Ligand field and intermolecular interactions tuning the magnetic properties of spin-crossover Fe(II) polymer with 4,4′-bipyridine

Energy Technology Data Exchange (ETDEWEB)

Luo, Yang-Hui; Liu, Qing-Ling; Yang, Li-Jing; Ling, Yang; Wang, Wei; Sun, Bai-Wang, E-mail: chmsunbw@seu.edu.cn

2015-02-15

A new spin crossover coordination polymer (SCO-CPs) of Fe(II)-4,4′-bipyridine (4,4′-bipy) family: (Fe(4,4′-bipy){sub 2}(H{sub 2}O){sub 2})·(4,4′-bipy)· 8(H{sub 2}O)·2(ClO{sub 4}) (3), which displays half spin transitions between 100 and 300 K, has been synthesized and structurally characterized. Compound 3 featured with two-dimensional (2-D) grids connected by hydrogen bonds and π…π packing between one-dimensional (1-D) chains, the 2-D grids expand to three-dimensional (3-D) architecture supported by a “S-shaped holder” involving lattice 4-4′-bipy, water molecules and perchlorate anion. We compared 3 with the other two analogous complexes: ((Fe(4,4′-bipy) (H{sub 2}O){sub 2} (NCS){sub 2})·4,4′-bipy, 1 and (Fe(4,4′-bipy){sub 2}(NCS){sub 2})·mSolv, 2) through Hirshfeld surfaces analysis, which revealed that the low ligand field strength (NCS{sup −}) and lone-pair…H contacts contribute to the stabilization of HS (high-spin) state of the Fe(II) ion, while the high ligand field strength (4,4′-bipy) and strong intermolecular contacts (hydrogen bonds and π…π packing interactions) make for the LS (low-spin) state. - Highlights: ●A new member of Fe(||)-4,4′-bipy family has been prepared. ●It displays half spin transitions tuned by ligand field and intermolecular interactions. ●We have made a detailed comparison of this new member with two other analogous complexes.

The role of phytochrome A and gibberellins in growth under long and short day conditions: Studies in hybrid aspen

Energy Technology Data Exchange (ETDEWEB)

Eriksson, M.E. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology

2000-07-01

This thesis addresses questions concerning the regulation of growth and, specifically, the cessation of growth in response to short days in deciduous tree species. The model tree used in the studies was hybrid aspen (Populus tremula L. x P. tremuloides Michx.). We have exploited the possibility of transforming this species to modulate the level of expression of target genes using over-expression and antisense techniques. The target genes in the studies were the photoreceptor phytochrome A (phyA) and gibberellin 20-oxidase (GA 20-oxidase), the latter being a highly regulated enzyme involved in the biosynthesis of gibberellins (GAs). The photoreceptor phyA has been implicated in photoperiodic regulation of growth, while GAs may regulate the physiological response further downstream. The endogenous expression of these genes has been investigated in parallel with studies of various plants with ectopic and reduced levels of expression. The main focus has been on the early stages of induction of growth cessation and its physiological and molecular mechanisms. Studies of hybrid aspen plants with an increased or reduced expression of phyA, show this receptor to mediate the photoperiodic regulation of growth. Plants with ectopic expression could not stop growing despite drastically shortened photoperiods, while the antisense plants showed the reverse phenotype, with a higher sensitivity resulting in earlier cessation of growth. The role of GAs in growth inhibition was also addressed using plants with a reduction in GA levels. These plants showed early cessation of growth and dormancy, and thus an increased sensitivity toward daylength. Conversely, plants with increased rates of GA biosynthesis showed increased growth and stopped growing much later. Furthermore, increases in GA biosynthesis, resulting in high levels of GAs have a major impact on growth. Plants with high GA levels have increased elongation and diameter growth, due to higher rates of cell production in the

Interaction of gravity and matter in the framework of N=4 supersymmetry

International Nuclear Information System (INIS)

Terent'ev, M.V.

1989-01-01

Procedure of constructing interaction of gravitation with only one non-Abelian matter multiplet is described. Compactification of 10-dimensional space R D (D=10) to R 4 space in the framework of N=1 supergravity theory was used. 14 refs

History and applications in controlled environments

Science.gov (United States)

Downs, R. J.

1994-01-01

The widespread application of electric (often called artificial) light in greenhouses, growing rooms, and plant growth chambers would presuppose that the role of phytochrome would be considered in the selection and use of such lighting systems. Unfortunately this is not usually the case. Part of the problem is that many students, and indeed an unfortunate number of senior scientists, seem to regard phytochrome as a laboratory phenomenon without much application in the real world. They simply have not grasped the concept that phytochrome is functioning through all stages of plant development, wherever plants are grown. It is certainly true, as Meijer (1971) stated, that one cannot compare experimental results obtained under very strict laboratory conditions with plant irradiation in glasshouses and in growth rooms. When Karl Norris developed the first practical portable spectroradiometer about 1962, some of the first measurements were to determine the red/far-red ratios under tree canopies. These measurements showed clearly the predominance of far-red in the understory and suggested that far-red was contributing to the elongation exhibited by many species growing in the shade, and possibly was a factor in the induction of light requirements in seeds. Subsequently we used Catalpa leaves as far-red filters to make light-insensitive lettuce seed light requiring. Much more detailed work has since been done on phytochrome effects in the natural environment, and it is encouraging to note that efforts are bring made to apply phytochrome research to horticulture.

Effect of three-body interactions on the zero-temperature equation of state of HCP solid 4He

Science.gov (United States)

Barnes, Ashleigh L.; Hinde, Robert J.

2017-03-01

Previous studies have pointed to the importance of three-body interactions in high density 4He solids. However the computational cost often makes it unfeasible to incorporate these interactions into the simulation of large systems. We report the implementation and evaluation of a computationally efficient perturbative treatment of three-body interactions in hexagonal close packed solid 4He utilizing the recently developed nonadditive three-body potential of Cencek et al. This study represents the first application of the Cencek three-body potential to condensed phase 4He systems. Ground state energies from quantum Monte Carlo simulations, with either fully incorporated or perturbatively treated three-body interactions, are calculated in systems with molar volumes ranging from 21.3 cm3/mol down to 2.5 cm3/mol. These energies are used to derive the zero-temperature equation of state for comparison against existing experimental and theoretical data. The equations of state derived from both perturbative and fully incorporated three-body interactions are found to be in very good agreement with one another, and reproduce the experimental pressure-volume data with significantly better accuracy than is obtained when only two-body interactions are considered. At molar volumes below approximately 4.0 cm3/mol, neither two-body nor three-body equations of state are able to accurately reproduce the experimental pressure-volume data, suggesting that below this molar volume four-body and higher many-body interactions are becoming important.

Conglutinin binds the HIV-1 envelope glycoprotein gp 160 and inhibits its interaction with cell membrane CD4

DEFF Research Database (Denmark)

Andersen, Ove; Sørensen, A M; Svehag, S E

1991-01-01

The highly glycosylated envelope glycoprotein (gp 160) of human immunodeficiency virus (HIV) interacts with the CD4 molecule present on the membrane of CD4+ cells and is involved in the pathobiology of HIV infection. Lectins bind glycoproteins through non-covalent interactions with specific hexose...... residues. The mammalian C-type lectin bovine conglutinin was examined for its ability to interact with recombinant gp160 (rgp160) produced in vaccinia virus-infected BHK21 cells. Specific binding of conglutinin to rgp160 was demonstrated by ELISA. The interaction of bovine conglutinin with rgp160...... of the binding of rgp160 to the CD4 receptor on CEM 13 cells, as demonstrated by FACS analyses. These results indicate that conglutinin may inhibit the infection with HIV-1 through its interaction with the viral envelope glycoprotein....

Mms1 is an assistant for regulating G-quadruplex DNA structures.

Science.gov (United States)

Schwindt, Eike; Paeschke, Katrin

2017-11-02

The preservation of genome stability is fundamental for every cell. Genomic integrity is constantly challenged. Among those challenges are also non-canonical nucleic acid structures. In recent years, scientists became aware of the impact of G-quadruplex (G4) structures on genome stability. It has been shown that folded G4-DNA structures cause changes in the cell, such as transcriptional up/down-regulation, replication stalling, or enhanced genome instability. Multiple helicases have been identified to regulate G4 structures and by this preserve genome stability. Interestingly, although these helicases are mostly ubiquitous expressed, they show specificity for G4 regulation in certain cellular processes (e.g., DNA replication). To this date, it is not clear how this process and target specificity of helicases are achieved. Recently, Mms1, an ubiquitin ligase complex protein, was identified as a novel G4-DNA-binding protein that supports genome stability by aiding Pif1 helicase binding to these regions. In this perspective review, we discuss the question if G4-DNA interacting proteins are fundamental for helicase function and specificity at G4-DNA structures.

CCHCR1 interacts with EDC4, suggesting its localization in P-bodies

Energy Technology Data Exchange (ETDEWEB)

Ling, Y.H.; Wong, C.C. [School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China); Li, K.W. [Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, 1081 HV Amsterdam (Netherlands); Chan, K.M. [School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China); Boukamp, P. [Division of Genetics of Skin Carcinogenesis, A110 German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Liu, W.K., E-mail: ken-liu@cuhk.edu.hk [School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China)

2014-09-10

Coiled‐coil alpha‐helical rod protein 1 (CCHCR1) is suggested as a candidate biomarker for psoriasis for more than a decade but its function remains poorly understood because of the inconsistent findings in the literature. CCHCR1 protein is suggested to be localized in the cytoplasm, nucleus, mitochondria, or centrosome and to regulate various cellular functions, including steroidogenesis, proliferation, differentiation, and cytoskeleton organization. In this study, we attempted to find a consensus between these findings by identifying the interaction partners of CCHCR1 using co-immunoprecipiation with a stable cell line expressing EGFP-tagged CCHCR1. Out of more than 100 co-immunoprecipitants identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), the enhancer of mRNA-decapping protein 4 (EDC4), which is a processing body (P-body) component, was particularly found to be the major interacting partner of CCHCR1. Confocal imaging confirmed the localization of CCHCR1 in P-bodies and its N-terminus is required for this subcellular localization, suggesting that CCHCR1 is a novel P-body component. As P-bodies are the site for mRNA metabolism, our findings provide a molecular basis for the function of CCHCR1, any disruption of which may affect the transcriptome of the cell, and causing abnormal cell functions. - Highlights: • We identified CCHCR1 as a novel P-body component. • We identified EDC4 as the major interacting partner of CCHCR1. • N-terminus of CCHCR1 protein is required for its P-bodies localization.

Coulomb and CH-π interactions in (6-4) photolyase-DNA complex dominate DNA binding and repair abilities.

Science.gov (United States)

Terai, Yuma; Sato, Ryuma; Yumiba, Takahiro; Harada, Ryuhei; Shimizu, Kohei; Toga, Tatsuya; Ishikawa-Fujiwara, Tomoko; Todo, Takeshi; Iwai, Shigenori; Shigeta, Yasuteru; Yamamoto, Junpei

2018-05-14

(6-4) Photolyases ((6-4)PLs) are flavoenzymes that repair the carcinogenic UV-induced DNA damage, pyrimidine(6-4)pyrimidone photoproducts ((6-4)PPs), in a light-dependent manner. Although the reaction mechanism of DNA photorepair by (6-4)PLs has been intensively investigated, the molecular mechanism of the lesion recognition remains obscure. We show that a well-conserved arginine residue in Xenopus laevis (6-4)PL (Xl64) participates in DNA binding, through Coulomb and CH-π interactions. Fragment molecular orbital calculations estimated attractive interaction energies of -80-100 kcal mol-1 for the Coulomb interaction and -6 kcal mol-1 for the CH-π interaction, and the loss of either of them significantly reduced the affinity for (6-4)PP-containing oligonucleotides, as well as the quantum yield of DNA photorepair. From experimental and theoretical observations, we formulated a DNA binding model of (6-4)PLs. Based on the binding model, we mutated this Arg in Xl64 to His, which is well conserved among the animal cryptochromes (CRYs), and found that the CRY-type mutant exhibited reduced affinity for the (6-4)PP-containing oligonucleotides, implying the possible molecular origin of the functional diversity of the photolyase/cryptochrome superfamily.

Identification of multi-loci hubs from 4C-seq demonstrates the functional importance of simultaneous interactions.

Science.gov (United States)

Jiang, Tingting; Raviram, Ramya; Snetkova, Valentina; Rocha, Pedro P; Proudhon, Charlotte; Badri, Sana; Bonneau, Richard; Skok, Jane A; Kluger, Yuval

2016-10-14

Use of low resolution single cell DNA FISH and population based high resolution chromosome conformation capture techniques have highlighted the importance of pairwise chromatin interactions in gene regulation. However, it is unlikely that associations involving regulatory elements act in isolation of other interacting partners that also influence their impact. Indeed, the influence of multi-loci interactions remains something of an enigma as beyond low-resolution DNA FISH we do not have the appropriate tools to analyze these. Here we present a method that uses standard 4C-seq data to identify multi-loci interactions from the same cell. We demonstrate the feasibility of our method using 4C-seq data sets that identify known pairwise and novel tri-loci interactions involving the Tcrb and Igk antigen receptor enhancers. We further show that the three Igk enhancers, MiEκ, 3'Eκ and Edκ, interact simultaneously in this super-enhancer cluster, which add to our previous findings showing that loss of one element decreases interactions between all three elements as well as reducing their transcriptional output. These findings underscore the functional importance of simultaneous interactions and provide new insight into the relationship between enhancer elements. Our method opens the door for studying multi-loci interactions and their impact on gene regulation in other biological settings. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Chemical interactions between as-received and pre-oxidized Zircaloy-4 and Inconel-718 at high temperatures

International Nuclear Information System (INIS)

Hofmann, P.; Markiewicz, M.

1994-06-01

Isothermal reaction experiments were performed in the temperature range of 1000 - 1300 C in order to determine the chemical interactions between Zircaloy-4 fuel rod cladding and Inconel-718 spacer grids of Pressurized Water Reactors (PWR) under severe accident conditions. It was not possible to apply even higher temperatures since fast and complete liquefaction of the components occurred as a result of eutectic interactions during heatup. The liquid reaction products formed enhance and accelerate the degradation of the material couples and the fuel elements, respectively. Only small amounts of Inconel are necessary to liquefy large amounts of Zircaloy. Thin oxide layers on the Zircaloy surface delay the beginning of the chemical interactions with Inconel but cannot prevent them. In this work the reaction kinetics have been determined for the system: as-received and pre-oxidized Zircaloy-4/Inconel 718. The interactions can be described by parabolic rate laws; the Arrhenius equations for the various interactions are given. (orig.) [de

Interchannel interaction in orientation and alignment of Kr 4p4mp states in the region of 3d9np resonances

International Nuclear Information System (INIS)

Lagutin, B M; Petrov, I D; Sukhorukov, V L; Werner, L; Klumpp, S; Ehresmann, A; Schartner, K-H; Schmoranzer, H

2009-01-01

The interaction between intermediate channels which influence the population of Kr 4p 4 mp ionic states in the region of the 3d 9 np resonances by the photon-induced Auger decay was investigated. The most important influence on the investigated process stems from 4p 5 ε'l and 3d 9 ε'l channels.

Interaction of maternal atopy, CTLA-4 gene polymorphism and gender on antenatal immunoglobulin E production.

Science.gov (United States)

Yang, K D; Ou, C-Y; Hsu, T-Y; Chang, J-C; Chuang, H; Liu, C-A; Liang, H-M; Kuo, H-C; Chen, R-F; Huang, E-Y

2007-05-01

Genetic heritability and maternal atopy have been correlated to antenatal IgE production, but very few studies have studied gene-maternal atopy interaction on antenatal IgE production. This study investigated the interaction of CTLA-4 polymorphism with prenatal factors on the elevation of cord blood IgE (CBIgE). Pregnant women were antenatally recruited for collection of prenatal environmental factors by a questionnaire. Umbilical cord blood samples were collected for CBIgE detection by fluorescence-linked enzyme assay and CTLA-4 polymorphism measurement by restriction fragment length polymorphism. A total of 1104 pregnant women initially participated in this cohort study, and 898 of them completed cord blood collection. 21.4% of the newborns had elevation of CBIgE (>or=0.5 kU/L). The CTLA-4+49A allele (P=0.021), maternal atopy (Ppaternal atopy, were significantly correlated with the CBIgE elevation in multivariate analysis. A dichotomous analysis of gene-maternal atopy interactions identified maternal atopy and CTLA-4+49A allele had an additive effect on the CBIgE elevation, especially prominent in male newborns; and in the absence of maternal atopy, CTLA-4+49GG genotype had a protective effect on CBIgE elevation in female newborns. Maternal but not paternal atopy has significant impacts on CBIgE elevation depending on gender and CTLA-4+49A/G polymorphism of newborns. Control of maternal atopy and modulation of CTLA-4 expression in the prenatal stage may be a target for the early prevention of perinatal allergy sensitization.

Dopamine D4 Receptor Polymorphism and Sex Interact to Predict Children's Affective Knowledge

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Sharon eBen-Israel

2015-06-01

Full Text Available Affective knowledge, the ability to understand others’ emotional states, is considered to be a fundamental part in efficient social interaction. Affective knowledge can be seen as related to cognitive empathy, and in the framework of Theory of Mind (ToM as affective ToM. Previous studies found that cognitive empathy and ToM are heritable, yet little is known regarding the specific genes involved in individual variability in affective knowledge. Investigating the genetic basis of affective knowledge is important for understanding brain mechanisms underlying socio-cognitive abilities. The 7-repeat (7R allele within the third exon of the Dopamine D4 receptor gene (DRD4-III has been a focus of interest, due to accumulated knowledge regarding its relevance to individual differences in prosocial behavior. A recent study suggests that an interaction between the DRD4-III polymorphism and sex is associated with cognitive empathy among adults. We aimed to examine the same association in two childhood age groups. Children (N = 280, age 3.5 years, N = 283, age 5 years participated as part of the Longitudinal Israel Study of Twins (LIST. Affective knowledge was assessed through children’s responses to an illustrated story describing different emotional situations, told in a laboratory setting. The findings suggest a significant interaction between sex and the DRD4-III polymorphism, replicated in both age groups. Boy carriers of the 7R allele had higher affective knowledge scores than girls, whereas in the absence of the 7R there was no significant sex effect on affective knowledge. The results support the importance of DRD4-III polymorphism and sex differences to social development. Possible explanations for differences from adult findings are discussed, as are pathways for future studies.

Study of the interactions of PAMAM-NH2 G4 dendrimer with selected natural amino acids in aqueous solutions

International Nuclear Information System (INIS)

Buczkowski, Adam; Palecz, Bartlomiej

2014-01-01

Highlights: • Calorimetric titration and dilution calorimetry show strong interactions between PAMAM-NH 2 G4 dendrimer and amino acids. • The more polar the amino acid side chain, the more exothermic the effects of the direct interactions with dendrimer. • Macromolecule of PAMAM-NH 2 G4 dendrimer can coordinate 20 to 40 molecules of amino acid. -- Abstract: The interactions of PAMAM-NH 2 G4 dendrimer with selected natural amino acids (Gly, Ala, Val, Leu, Ile, Phe, Ser, Thr, Met, Asn, Gln, Pro and Trp) in aqueous solutions were measured with the use of the techniques of calorimetric titration and dilution calorimetry. The results of calorimetric measurements show strong interactions between PAMAM-NH 2 G4 dendrimer and amino acids with polar substituents. A macromolecule of PAMAM-NH 2 G4 dendrimer can coordinate 20 to 40 molecules of amino acid

Moessbauer studies of superexchange interactions in NiFe sub 2 O sub 4

CERN Document Server

Kim, S J; Kim, C S; Lee, S W

2000-01-01

NiFe sub 2 O sub 4 has been studied using Moessbauer spectroscopy and X-ray diffraction. The crystal was found to have a inverse cubic spinel structure with the lattice constant a sub 0 =8.326+-0.003 A. Moessbauer spectra of NiFe sub 2 O sub 4 was obtained at various absorber temperatures from 13 K to the Neel temperature. The Moessbauer spectra consisted of two sets of six lines corresponding to Fe sup + sup 3 at the tetrahedral (A) and the octahedral (B) sites. The temperature dependence of the magnetic hyperfine fields at sup 5 sup 7 Fe nuclei at the tetrahedral (A) and the octahedral (B) sites was analyzed by the Neel theory of ferrimagnetism. The intersublattice A-O-B and intrasublattice A-O-A superexchange interactions were found to be antiferromagnetic with strengths of J sub A sub - sub B =-25.0 k sub B and J sub A sub - sub A =-4.0 K sub B , respectively, while the intrasublattice B-O-B superexchange interaction is ferromagnetic with a strength J sub B sub - sub B =4.2 k sub B.

Protein structure modelling and evaluation based on a 4-distance description of side-chain interactions

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Inbar Yuval

2010-07-01

Full Text Available Abstract Background Accurate evaluation and modelling of residue-residue interactions within and between proteins is a key aspect of computational structure prediction including homology modelling, protein-protein docking, refinement of low-resolution structures, and computational protein design. Results Here we introduce a method for accurate protein structure modelling and evaluation based on a novel 4-distance description of residue-residue interaction geometry. Statistical 4-distance preferences were extracted from high-resolution protein structures and were used as a basis for a knowledge-based potential, called Hunter. We demonstrate that 4-distance description of side chain interactions can be used reliably to discriminate the native structure from a set of decoys. Hunter ranked the native structure as the top one in 217 out of 220 high-resolution decoy sets, in 25 out of 28 "Decoys 'R' Us" decoy sets and in 24 out of 27 high-resolution CASP7/8 decoy sets. The same concept was applied to side chain modelling in protein structures. On a set of very high-resolution protein structures the average RMSD was 1.47 Å for all residues and 0.73 Å for buried residues, which is in the range of attainable accuracy for a model. Finally, we show that Hunter performs as good or better than other top methods in homology modelling based on results from the CASP7 experiment. The supporting web site http://bioinfo.weizmann.ac.il/hunter/ was developed to enable the use of Hunter and for visualization and interactive exploration of 4-distance distributions. Conclusions Our results suggest that Hunter can be used as a tool for evaluation and for accurate modelling of residue-residue interactions in protein structures. The same methodology is applicable to other areas involving high-resolution modelling of biomolecules.

Cocrystals of kaempferol, quercetin and myricetin with 4,4‧-bipyridine: Crystal structures, analyses of intermolecular interactions and antibacterial properties

Science.gov (United States)

Zhang, Yu-Nan; Yin, He-Mei; Zhang, Yu; Zhang, Da-Jun; Su, Xin; Kuang, Hai-Xue

2017-02-01

With an aim to explore the interactions of Osbnd H⋯N between hydroxyl moiety of the flavonoids and the pyridyl ring of N-containing aromatic amines, three flavonols with varying B-ring-hydroxyl groups (kaempferol, quercetin, and myricetin) were selected to combine with 4,4‧-bipyridine. As a result, three new cocrystals of flavonols were obtained with a solution evaporation approach. These three cocrystals were characterized by single crystal X-ray diffraction, XPRD, IR and NMR methods. The resulting cocrystals were kaempferol: 4,4‧-bipyridine (2:1) (KAE·BPY·2H2O), quercetin: 4,4‧-bipyridine (1:1.5) (QUE·BPY), and myricetin: 4,4‧-bipyridine (1:2) (MYR·BPY·H2O). Structural analyses show that an array of hydrogen bonds and π-π stacking interactions interconnect the molecules to form a two-dimensional (2D) supramolecular layer in KAE·BPY·2H2O, QUE·BPY, and MYR·BPY·H2O. In the three cocrystals, they present as three different synthons-ⅠR88(58), Ⅳ R44(42) and, Ⅶ R66(29) with 4,4‧-bipyridine, respectively-which may yield a strategy for constructing the supramolecule. Cocrystals of flavonols combined with N-containing aromatic amines, 7-OH, B-ring-hydroxyl number and/or the location of the flavonols to play a significant part in extending the dimensionality of the cocrystals. The resulting motif formation and crystal packing in these flavonols cocrystals has combined with N-containing aromatic amines. Additionally, the antibacterial properties of the three cocrystals against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) have been investigated.

Interactions of the human MCM-BP protein with MCM complex components and Dbf4.

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Tin Nguyen

Full Text Available MCM-BP was discovered as a protein that co-purified from human cells with MCM proteins 3 through 7; results which were recapitulated in frogs, yeast and plants. Evidence in all of these organisms supports an important role for MCM-BP in DNA replication, including contributions to MCM complex unloading. However the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood. Here we show that human MCM-BP is capable of interacting with individual MCM proteins 2 through 7 when co-expressed in insect cells and can greatly increase the recovery of some recombinant MCM proteins. Glycerol gradient sedimentation analysis indicated that MCM-BP interacts most strongly with MCM4 and MCM7. Similar gradient analyses of human cell lysates showed that only a small amount of MCM-BP overlapped with the migration of MCM complexes and that MCM complexes were disrupted by exogenous MCM-BP. In addition, large complexes containing MCM-BP and MCM proteins were detected at mid to late S phase, suggesting that the formation of specific MCM-BP complexes is cell cycle regulated. We also identified an interaction between MCM-BP and the Dbf4 regulatory component of the DDK kinase in both yeast 2-hybrid and insect cell co-expression assays, and this interaction was verified by co-immunoprecipitation of endogenous proteins from human cells. In vitro kinase assays showed that MCM-BP was not a substrate for DDK but could inhibit DDK phosphorylation of MCM4,6,7 within MCM4,6,7 or MCM2-7 complexes, with little effect on DDK phosphorylation of MCM2. Since DDK is known to activate DNA replication through phosphorylation of these MCM proteins, our results suggest that MCM-BP may affect DNA replication in part by regulating MCM phosphorylation by DDK.

Interactions of the human MCM-BP protein with MCM complex components and Dbf4.

Science.gov (United States)

Nguyen, Tin; Jagannathan, Madhav; Shire, Kathy; Frappier, Lori

2012-01-01

MCM-BP was discovered as a protein that co-purified from human cells with MCM proteins 3 through 7; results which were recapitulated in frogs, yeast and plants. Evidence in all of these organisms supports an important role for MCM-BP in DNA replication, including contributions to MCM complex unloading. However the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood. Here we show that human MCM-BP is capable of interacting with individual MCM proteins 2 through 7 when co-expressed in insect cells and can greatly increase the recovery of some recombinant MCM proteins. Glycerol gradient sedimentation analysis indicated that MCM-BP interacts most strongly with MCM4 and MCM7. Similar gradient analyses of human cell lysates showed that only a small amount of MCM-BP overlapped with the migration of MCM complexes and that MCM complexes were disrupted by exogenous MCM-BP. In addition, large complexes containing MCM-BP and MCM proteins were detected at mid to late S phase, suggesting that the formation of specific MCM-BP complexes is cell cycle regulated. We also identified an interaction between MCM-BP and the Dbf4 regulatory component of the DDK kinase in both yeast 2-hybrid and insect cell co-expression assays, and this interaction was verified by co-immunoprecipitation of endogenous proteins from human cells. In vitro kinase assays showed that MCM-BP was not a substrate for DDK but could inhibit DDK phosphorylation of MCM4,6,7 within MCM4,6,7 or MCM2-7 complexes, with little effect on DDK phosphorylation of MCM2. Since DDK is known to activate DNA replication through phosphorylation of these MCM proteins, our results suggest that MCM-BP may affect DNA replication in part by regulating MCM phosphorylation by DDK.

Wave-Vector Dependence of the Jahn-Teller Interactions in TmVO4

DEFF Research Database (Denmark)

Kjems, Jørgen; Hayes, W.; Smith, S. H.

1975-01-01

The resonant Jahn-Teller coupling of the B2g acoustic phonon and the Zeeman-split ground doublet in TmVO4 has been studied by inelastic neutron scattering. Tuning of the magnetic field provides a means for investigating the wave-vector dependence of the interactions. We find that the coupling...

Amlexanox Blocks the Interaction between S100A4 and Epidermal Growth Factor and Inhibits Cell Proliferation.

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Ching Chang Cho

Full Text Available The human S100A4 protein binds calcium, resulting in a change in its conformation to promote the interaction with its target protein. Human epidermal growth factor (EGF is the target protein of S100A4 and a critical ligand of the receptor EGFR. The EGF/EGFR system promotes cell survival, differentiation, and growth by activating several signaling pathways. Amlexanox is an anti-inflammatory and anti-allergic drug that is used to treat recurrent aphthous ulcers. In the present study, we determined that amlexanox interacts with S100A4 using heteronuclear single quantum correlation titration. We elucidated the interactions of S100A4 with EGF and amlexanox using fluorescence and nuclear magnetic resonance spectroscopy. We generated two binary models (for the S100A4-EGF and S100A4-amlexanox complexes and observed that amlexanox and EGF share a similar binding region in mS100A4. We also used a WST-1 assay to investigate the bioactivity of S100A4, EGF, and amlexanox, and found that amlexanox blocks the binding between S100A4 and EGF, and is therefore useful for the development of new anti-proliferation drugs.

Intersubunit distances in full-length, dimeric, bacterial phytochrome Agp1, as measured by pulsed electron-electron double resonance (PELDOR) between different spin label positions, remain unchanged upon photoconversion.

Science.gov (United States)

Kacprzak, Sylwia; Njimona, Ibrahim; Renz, Anja; Feng, Juan; Reijerse, Edward; Lubitz, Wolfgang; Krauss, Norbert; Scheerer, Patrick; Nagano, Soshichiro; Lamparter, Tilman; Weber, Stefan

2017-05-05

Bacterial phytochromes are dimeric light-regulated histidine kinases that convert red light into signaling events. Light absorption by the N-terminal photosensory core module (PCM) causes the proteins to switch between two spectrally distinct forms, Pr and Pfr, thus resulting in a conformational change that modulates the C-terminal histidine kinase region. To provide further insights into structural details of photoactivation, we investigated the full-length Agp1 bacteriophytochrome from the soil bacterium Agrobacterium fabrum using a combined spectroscopic and modeling approach. We generated seven mutants suitable for spin labeling to enable application of pulsed EPR techniques. The distances between attached spin labels were measured using pulsed electron-electron double resonance spectroscopy to probe the arrangement of the subunits within the dimer. We found very good agreement of experimental and calculated distances for the histidine-kinase region when both subunits are in a parallel orientation. However, experimental distance distributions surprisingly showed only limited agreement with either parallel- or antiparallel-arranged dimer structures when spin labels were placed into the PCM region. This observation indicates that the arrangements of the PCM subunits in the full-length protein dimer in solution differ significantly from that in the PCM crystals. The pulsed electron-electron double resonance data presented here revealed either no or only minor changes of distance distributions upon Pr-to-Pfr photoconversion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

An isoform of eukaryotic initiation factor 4E from Chrysanthemum morifolium interacts with Chrysanthemum virus B coat protein.

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Aiping Song

Full Text Available BACKGROUND: Eukaryotic translation initiation factor 4E (eIF4E plays an important role in plant virus infection as well as the regulation of gene translation. METHODOLOGY/PRINCIPAL FINDINGS: Here, we describe the isolation of a cDNA encoding CmeIF(iso4E (GenBank accession no. JQ904592, an isoform of eIF4E from chrysanthemum, using RACE PCR. We used the CmeIF(iso4E cDNA for expression profiling and to analyze the interaction between CmeIF(iso4E and the Chrysanthemum virus B coat protein (CVBCP. Multiple sequence alignment and phylogenetic tree analysis showed that the sequence similarity of CmeIF(iso4E with other reported plant eIF(iso4E sequences varied between 69.12% and 89.18%, indicating that CmeIF(iso4E belongs to the eIF(iso4E subfamily of the eIF4E family. CmeIF(iso4E was present in all chrysanthemum organs, but was particularly abundant in the roots and flowers. Confocal microscopy showed that a transiently transfected CmeIF(iso4E-GFP fusion protein distributed throughout the whole cell in onion epidermis cells. A yeast two hybrid assay showed CVBCP interacted with CmeIF(iso4E but not with CmeIF4E. BiFC assay further demonstrated the interaction between CmeIF(iso4E and CVBCP. Luminescence assay showed that CVBCP increased the RLU of Luc-CVB, suggesting CVBCP might participate in the translation of viral proteins. CONCLUSIONS/SIGNIFICANCE: These results inferred that CmeIF(iso4E as the cap-binding subunit eIF(iso4F may be involved in Chrysanthemum Virus B infection in chrysanthemum through its interaction with CVBCP in spatial.

Study of the biochemical effects of ionizing and nonionizing radiation on plant metabolism during development. Progress report, September 1, 1976--November 30, 1977

International Nuclear Information System (INIS)

Klein, W.H.

1977-01-01

Studies on spectral distribution and its control of plant growth and development included spectral quality measurements and biological responses. Spectral quality measurements consisted of spectral monitoring, the erythmal band, and testing of solar collectors. A physiological system for determining biological response was the photoperiodic response to the induction of flowering by long days in Hordeum vulgare; the design of the system was intended to test whether or not changes in the spectral distribution of natural daylight are capable of controlling photoperiodism. Biological responses were also determined by phytochrome measurements. Photostationary states of phytochrome were determined from white light grown tissue and the effect of changes in the red to far-red ratio on phytochrome was assessed. Experimental results are reported for studies on effects of pulsed light on plant productivity

Multiplicity distributions of projectile fragments in interactions of nuclei with emulsion at 4.1-4.5 A GeV/c

International Nuclear Information System (INIS)

Fakhraddin, S; Rahim, Magda A

2008-01-01

The results of our systematic studies of projectile fragments (PFs) multiplicity distributions in interactions of 4 He, 12 C, 16 O, 22 Ne and 28 Si with emulsion at 4.1-4.5 A GeV/c are presented in this paper. The mean values for the three different multiplicities of PFs at nearly the same energy are given. The dependence of these mean values on the projectile mass number A p , as well as the dependence of the PFs on target groups (H, CNO and AgBr), has been investigated

ZFHX4 interacts with the NuRD core member CHD4 and regulates the glioblastoma tumor-initiating cell state.

Science.gov (United States)

Chudnovsky, Yakov; Kim, Dohoon; Zheng, Siyuan; Whyte, Warren A; Bansal, Mukesh; Bray, Mark-Anthony; Gopal, Shuba; Theisen, Matthew A; Bilodeau, Steve; Thiru, Prathapan; Muffat, Julien; Yilmaz, Omer H; Mitalipova, Maya; Woolard, Kevin; Lee, Jeongwu; Nishimura, Riko; Sakata, Nobuo; Fine, Howard A; Carpenter, Anne E; Silver, Serena J; Verhaak, Roel G W; Califano, Andrea; Young, Richard A; Ligon, Keith L; Mellinghoff, Ingo K; Root, David E; Sabatini, David M; Hahn, William C; Chheda, Milan G

2014-01-30

Glioblastoma (GBM) harbors subpopulations of therapy-resistant tumor-initiating cells (TICs) that are self-renewing and multipotent. To understand the regulation of the TIC state, we performed an image-based screen for genes regulating GBM TIC maintenance and identified ZFHX4, a 397 kDa transcription factor. ZFHX4 is required to maintain TIC-associated and normal human neural precursor cell phenotypes in vitro, suggesting that ZFHX4 regulates differentiation, and its suppression increases glioma-free survival in intracranial xenografts. ZFHX4 interacts with CHD4, a core member of the nucleosome remodeling and deacetylase (NuRD) complex. ZFHX4 and CHD4 bind to overlapping sets of genomic loci and control similar gene expression programs. Using expression data derived from GBM patients, we found that ZFHX4 significantly affects CHD4-mediated gene expression perturbations, which defines ZFHX4 as a master regulator of CHD4. These observations define ZFHX4 as a regulatory factor that links the chromatin-remodeling NuRD complex and the GBM TIC state. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

ZFHX4 interacts with the NuRD core member CHD4 and regulates the glioblastoma tumor initiating cell state

Science.gov (United States)

Chudnovsky, Yakov; Kim, Dohoon; Zheng, Siyuan; Whyte, Warren A.; Bansal, Mukesh; Bray, Mark-Anthony; Gopal, Shuba; Theisen, Matthew A.; Bilodeau, Steve; Thiru, Prathapan; Muffat, Julien; Yilmaz, Omer H.; Mitalipova, Maya; Woolard, Kevin; Lee, Jeongwu; Nishimura, Riko; Sakata, Nobuo; Fine, Howard A.; Carpenter, Anne E.; Silver, Serena J.; Verhaak, Roel G. W.; Califano, Andrea; Young, Richard A.; Ligon, Keith L.; Mellinghoff, Ingo K.; Root, David E.; Sabatini, David M.; Hahn, William C.; Chheda, Milan G.

2014-01-01

Summary Glioblastomas (GBM) harbor subpopulations of therapy-resistant tumor initiating cells (TICs) that are self-renewing and multipotent. To understand the regulation of the TIC state, we performed an image-based screen for genes regulating GBM TIC maintenance and identified ZFHX4, a 397-kDa transcription factor. ZFHX4 is required to maintain TIC-associated and normal human neural precursor cell phenotypes in vitro, suggesting that ZFHX4 regulates differentiation, and its suppression increases glioma-free survival in intracranial xenografts. ZFHX4 interacts with CHD4, a core member of the NuRD (nucleosome remodeling and deacetylase) complex. ZFHX4 and CHD4 bind to overlapping sets of genomic loci and control similar gene expression programs. Using expression data derived from GBM patients, we found that ZFHX4 significantly affects CHD4-mediated gene expression perturbations, which defines ZFHX4 as a master regulator of CHD4. These observations define ZFHX4 as a regulatory factor that links the chromatin remodeling NuRD complex and the GBM TIC state. PMID:24440720

ZFHX4 Interacts with the NuRD Core Member CHD4 and Regulates the Glioblastoma Tumor-Initiating Cell State

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Yakov Chudnovsky

2014-01-01

Full Text Available Glioblastoma (GBM harbors subpopulations of therapy-resistant tumor-initiating cells (TICs that are self-renewing and multipotent. To understand the regulation of the TIC state, we performed an image-based screen for genes regulating GBM TIC maintenance and identified ZFHX4, a 397 kDa transcription factor. ZFHX4 is required to maintain TIC-associated and normal human neural precursor cell phenotypes in vitro, suggesting that ZFHX4 regulates differentiation, and its suppression increases glioma-free survival in intracranial xenografts. ZFHX4 interacts with CHD4, a core member of the nucleosome remodeling and deacetylase (NuRD complex. ZFHX4 and CHD4 bind to overlapping sets of genomic loci and control similar gene expression programs. Using expression data derived from GBM patients, we found that ZFHX4 significantly affects CHD4-mediated gene expression perturbations, which defines ZFHX4 as a master regulator of CHD4. These observations define ZFHX4 as a regulatory factor that links the chromatin-remodeling NuRD complex and the GBM TIC state.

Interactions in γ-Fe2O3 and Fe3O4 nanoparticle systems

International Nuclear Information System (INIS)

Laha, S.S.; Tackett, R.J.; Lawes, G.

2014-01-01

We have investigated interaction effects in two different systems of iron oxide nanoparticles. Samples of γ-Fe 2 O 3 and Fe 3 O 4 nanoparticles were synthesized using a matrix-mediated precipitation reaction and a chemical co-precipitation technique respectively. The structural properties of these nanoparticles were studied using x-ray diffraction and transmission electron microscopy. We also used temperature dependent ac magnetic susceptibility measurements to carefully investigate the interactions among these nanoparticles. Our analysis showed that the characteristic interaction energy does not depend simply on the average spacing between the nanoparticles but is likely to be strongly influenced by the fluctuations in the nanoparticle distribution

E4 properties in deformed nuclei and the sdg interacting boson model

NARCIS (Netherlands)

Wu, H.C.; Dieperink, A. E. L.; Scholten, O.; Harakeh, M. N.; de Leo, R.; Pignanelli, M.; Morrison, I.

1988-01-01

The hexadecapole transition strength distribution is measured for the deformed nucleus 150Nd using the (p,p') reaction at Ep=30 MeV. The experimental information on B(E4) values in this nucleus and in 156Gd is interpreted in the framework of the sdg interacting boson model. It is found that the main

Professional paradox: identity formation in qualified doctors pursuing further training.

Science.gov (United States)

Chan, Mercedes; Pratt, Dan; Poole, Gary; Sidhu, Ravi

2018-03-01

Many newly qualified specialists and subspecialists pursue additional training. Although their motivations are many, the pursuit of further training as an alternative to unemployment is an emerging trend. Paradoxically, doctors continue as trainees with a consultant's credentials, and without the guarantee of eventual employment. This study explores seven doctors' experiences, the effects of further training on their professional identity formation (PIF), and how these effects are reconciled on a personal and professional level. This phenomenological study involved interviews with seven qualified Canadian specialists (three were female) who pursued additional training in response to a lack of available positions in their respective specialties. Template analysis generated theoretical constructs of influences on their PIF, and characteristics of their lived experiences. Four themes shaped PIF: setting and context; language and communication; responsibilities and privileges; and participants' visions of their future selves. Professional identity formation (PIF) continued to develop in further training, but was inconsistently affirmed by participants' communities of practice. Four major themes characterised training experiences: prescription; managing multiple masters; limiting access to others and community ties; and constantly questioning the value of extra training. Qualified doctors traverse professional paradoxes as they seek further education with no guarantee of employment and provide consultant-level care as 'trainees'. An identity dissonance emerges that may continue until a clear identity is prescribed for them. Although disruptive to these doctors' PIF and personal and professional lives, the long-term effects of additional training are unknown. Its utility and influence on securing employment and future job satisfaction are areas for further research. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

Highly selective and stable carbon dioxide uptake in polyindole-derived microporous carbon materials.

Science.gov (United States)

Saleh, Muhammad; Tiwari, Jitendra N; Kemp, K Christain; Yousuf, Muhammad; Kim, Kwang S

2013-05-21

Adsorption with solid sorbents is considered to be one of the most promising methods for the capture of carbon dioxide (CO₂) from power plant flue gases. In this study, microporous carbon materials used for CO₂ capture were synthesized by the chemical activation of polyindole nanofibers (PIF) at temperatures from 500 to 800 °C using KOH, which resulted in nitrogen (N)-doped carbon materials. The N-doped carbon materials were found to be microporous with an optimal adsorption pore size for CO₂ of 0.6 nm and a maximum (Brunauer-Emmett-Teller) BET surface area of 1185 m(2) g(-1). The PIF activated at 600 °C (PIF6) has a surface area of 527 m(2) g(-1) and a maximum CO₂ storage capacity of 3.2 mmol g(-1) at 25 °C and 1 bar. This high CO₂ uptake is attributed to its highly microporous character and optimum N content. Additionally, PIF6 material displays a high CO₂ uptake at low pressure (1.81 mmol g(-1) at 0.2 bar and 25 °C), which is the best low pressure CO₂ uptake reported for carbon-based materials. The adsorption capacity of this material remained remarkably stable even after 10 cycles. The isosteric heat of adsorption was calculated to be in the range of 42.7-24.1 kJ mol(-1). Besides the excellent CO₂ uptake and stability, PIF6 also exhibits high selectivity values for CO₂ over N₂, CH₄, and H₂ of 58.9, 12.3, and 101.1 at 25 °C, respectively, and these values are significantly higher than reported values.

Isolation and determination antimicrobial susceptibility pattern of Enterobacter cloacae strains isolated from consumed powdered infant formula milk in NICU ward

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Jalal Mardaneh

2014-11-01

Full Text Available Background: Enterobacter cloacae is a rod-shaped, gram-negative bacillus, from the family of Enterobacteriaceae. It is an opportunistic pathogen and causes disease in plants and humans (premature and immunocompromised persons of all age groups. The goal of this study was to isolate and determine antimicrobial susceptibility pattern of Enterobacter cloacae strains isolated from consumed powdered infant formula (PIF milk in Neonatal Intensive Care Unit (NICU ward. Material and Methods: In this cross-sectional study, a total of 125 consumed powdered infant formula milk in NICU ward were surveyed. Isolation and Identification of microorganisms was carried out according to FDA method. Antimicrobial susceptibility test was performed using the standard disc diffusion method based on CLSI (2011 recommendations. Results: Enterobacter cloacae was isolated from 2 (1.6% of 125 PIF milk samples. The results showed that isolated strains are sensitive to most antibiotics. All isolates were resistant to amoxicillin. Conclusion: Since the infant formula (PIF samples are unsterile products and contamination could occure during different steps, it is imperative to prepare the infant formula milk foods according to the manufacturer’s instruction and in an aseptic condition. Contamination of PIF only could be reduced or prevented by monitoring the critical control points and taking appropriate action during the processing.

Ion-ion interaction and energy transfer of 4+ transuranium ions in cerium tetrafluoride

International Nuclear Information System (INIS)

Liu, G.K.; Beitz, J.V.

1990-01-01

Dynamics of excited 5f electron states of the transuranium ions Cm 4+ and Bk 4+ in CeF 4 are compared. Based on time- and wavelength-resolved laser-induced fluorescence, excitation energy transfer processes have been probed. Depending on concentration and electronic energy level structure of the studied 4+ transuranium ion, the dominant energy transfer mechanisms were identified as cross relaxation, exciton-exciton annihilation, and trapping. Energy transfer rates derived from the fitting of the observed fluorescence decays to theoretical models, based on electric multipolar ion-ion interactions, are contrasted with prior studies of 4f states of 3+ lanthanide and 3d states of transition metal ions. 16 refs., 1 tab

Comparative exposure to DEHP from food contact materials: application of the product intake fraction

DEFF Research Database (Denmark)

Ernstoff, Alexi; Jolliet, Olivier; Fantke, Peter

Quantitative Sustainability Assessment Food contact materials (FCM), e.g. bottles and food handling gloves, can contain potentially endocrine disrupting chemicals, such as di-2-ethylhexyl phthalate(DEHP, CAS: 117-81-7). To investigate the contribution of FCM to dietary DEHP exposure we apply...... thresholds. A hypothetical average PiF for the FCM sector was calculated via production volume and oral exposure doses estimated from NHANES data. In both cases the indication was gloves may contribute more to DEHP exposure when used with certain food items than bottled water. DEHP content in gloves greater...... than 5% would cause exceedance of US EPA threshold when used with certain food items,e.g. radishes based on PiF calculated here. The PiF used in thís context has applications for regulations related to FCM and exposure assessments on a per unit kilo basis....

Study on neutron interactions with protons and carbon nuclei at p=4.2 GeV/c

International Nuclear Information System (INIS)

Bekmirzaev, R.N.; Muminov, M.M.; Sultanov, M.U.; Grishina, O.V.; Dolejsi, J.; Tas, P.; Trka, Z.

1988-01-01

The production of neutrons with p=4.2 GeV/c in d(C 3 H 8 ) collisions and their interaction with proton and carbon nuclei are studied. The experimental material has been obtained using the 2m propane bubble chamber irradiated by deuterons with p=4.2 GeV/c per nucleon at the Dubna synchrophasotron, JINR. The data on multiplicity and momentum characteristics of secondary particles in np and nC interactions compared with the calculations on the LUND model are obtained

Vfa1 Binds to the N-terminal Microtubule-interacting and Trafficking (MIT) Domain of Vps4 and Stimulates Its ATPase Activity*

Science.gov (United States)

Vild, Cody J.; Xu, Zhaohui

2014-01-01

The endosomal sorting complexes required for transport (ESCRT) are responsible for multivesicular body biogenesis, membrane abscission during cytokinesis, and retroviral budding. They function as transiently assembled molecular complexes on the membrane, and their disassembly requires the action of the AAA-ATPase Vps4. Vps4 is regulated by a multitude of ESCRT and ESCRT-related proteins. Binding of these proteins to Vps4 is often mediated via the microtubule-interacting and trafficking (MIT) domain of Vps4. Recently, a new Vps4-binding protein Vfa1 was identified in a yeast genetic screen, where overexpression of Vfa1 caused defects in vacuolar morphology. However, the function of Vfa1 and its role in vacuolar biology were largely unknown. Here, we provide the first detailed biochemical and biophysical study of Vps4-Vfa1 interaction. The MIT domain of Vps4 binds to the C-terminal 17 residues of Vfa1. This interaction is of high affinity and greatly stimulates the ATPase activity of Vps4. The crystal structure of the Vps4-Vfa1 complex shows that Vfa1 adopts a canonical MIT-interacting motif 2 structure that has been observed previously in other Vps4-ESCRT interactions. These findings suggest that Vfa1 is a novel positive regulator of Vps4 function. PMID:24567329

Vfa1 binds to the N-terminal microtubule-interacting and trafficking (MIT) domain of Vps4 and stimulates its ATPase activity.

Science.gov (United States)

Vild, Cody J; Xu, Zhaohui

2014-04-11

The endosomal sorting complexes required for transport (ESCRT) are responsible for multivesicular body biogenesis, membrane abscission during cytokinesis, and retroviral budding. They function as transiently assembled molecular complexes on the membrane, and their disassembly requires the action of the AAA-ATPase Vps4. Vps4 is regulated by a multitude of ESCRT and ESCRT-related proteins. Binding of these proteins to Vps4 is often mediated via the microtubule-interacting and trafficking (MIT) domain of Vps4. Recently, a new Vps4-binding protein Vfa1 was identified in a yeast genetic screen, where overexpression of Vfa1 caused defects in vacuolar morphology. However, the function of Vfa1 and its role in vacuolar biology were largely unknown. Here, we provide the first detailed biochemical and biophysical study of Vps4-Vfa1 interaction. The MIT domain of Vps4 binds to the C-terminal 17 residues of Vfa1. This interaction is of high affinity and greatly stimulates the ATPase activity of Vps4. The crystal structure of the Vps4-Vfa1 complex shows that Vfa1 adopts a canonical MIT-interacting motif 2 structure that has been observed previously in other Vps4-ESCRT interactions. These findings suggest that Vfa1 is a novel positive regulator of Vps4 function.

Specificity of interactions among the DNA-packaging machine components of T4-related bacteriophages.

Science.gov (United States)

Gao, Song; Rao, Venigalla B

2011-02-04

Tailed bacteriophages use powerful molecular motors to package the viral genome into a preformed capsid. Packaging at a rate of up to ∼2000 bp/s and generating a power density twice that of an automobile engine, the phage T4 motor is the fastest and most powerful reported to date. Central to DNA packaging are dynamic interactions among the packaging components, capsid (gp23), portal (gp20), motor (gp17, large "terminase"), and regulator (gp16, small terminase), leading to precise orchestration of the packaging process, but the mechanisms are poorly understood. Here we analyzed the interactions between small and large terminases of T4-related phages. Our results show that the gp17 packaging ATPase is maximally stimulated by homologous, but not heterologous, gp16. Multiple interaction sites are identified in both gp16 and gp17. The specificity determinants in gp16 are clustered in the diverged N- and C-terminal domains (regions I-III). Swapping of diverged region(s), such as replacing C-terminal RB49 region III with that of T4, switched ATPase stimulation specificity. Two specificity regions, amino acids 37-52 and 290-315, are identified in or near the gp17-ATPase "transmission" subdomain II. gp16 binding at these sites might cause a conformational change positioning the ATPase-coupling residues into the catalytic pocket, triggering ATP hydrolysis. These results lead to a model in which multiple weak interactions between motor and regulator allow dynamic assembly and disassembly of various packaging complexes, depending on the functional state of the packaging machine. This might be a general mechanism for regulation of the phage packaging machine and other complex molecular machines.

Mutations at the CXCR4 interaction sites for AMD3100 influence anti-CXCR4 antibody binding and HIV-1 entry

DEFF Research Database (Denmark)

Hatse, Sigrid; Princen, Katrien; Vermeire, Kurt

2003-01-01

The interaction of the CXCR4 antagonist AMD3100 with its target is greatly influenced by specific aspartate residues in the receptor protein, including Asp(171) and Asp(262). We have now found that aspartate-to-asparagine substitutions at these positions differentially affect the binding of four...

Multiplicity distributions of projectile fragments in interactions of nuclei with emulsion at 4.1-4.5 A GeV/c

Energy Technology Data Exchange (ETDEWEB)

Fakhraddin, S; Rahim, Magda A [Physics Department, Faculty of Science, Sana' a University, Republic of Yemen (Yemen)], E-mail: sakinafa1@hotmail.com, E-mail: dr.magda2006@hotmail.com

2008-07-15

The results of our systematic studies of projectile fragments (PFs) multiplicity distributions in interactions of {sup 4}He, {sup 12}C, {sup 16}O, {sup 22}Ne and {sup 28}Si with emulsion at 4.1-4.5 A GeV/c are presented in this paper. The mean values for the three different multiplicities of PFs at nearly the same energy are given. The dependence of these mean values on the projectile mass number A{sub p}, as well as the dependence of the PFs on target groups (H, CNO and AgBr), has been investigated.

RECQ HELICASE RECQL4 PARTICIPATES IN NON-HOMOLOGOUS END JOINING AND INTERACTS WITH THE KU COMPLEX

DEFF Research Database (Denmark)

Shamanna, Raghavendra A; Singh, Dharmendra Kumar; Lu, Huiming

2014-01-01

-irradiation and resulted in accumulation of 53BP1 foci after irradiation, indicating defects in the processing of DSB. We find that RECQL4 interacts with the Ku70/Ku80 heterodimer, part of the DNA-dependent protein kinase (DNA-PK) complex, via its N-terminal domain. Further, RECQL4 stimulates higher order DNA binding...... of Ku70/Ku80 to a blunt end DNA substrate. Taken together, these results implicate that RECQL4 participates in the NHEJ pathway of DSB repair via a functional interaction with the Ku70/Ku80 complex. This is the first study to provide both in vitro and in vivo evidence for a role of a RecQ helicase...

NMR characterisation of the minimal interacting regions of centrosomal proteins 4.1R and NuMA1: effect of phosphorylation

Directory of Open Access Journals (Sweden)

Bruix Marta

2010-01-01

Full Text Available Abstract Background Some functions of 4.1R in non-erythroid cells are directly related with its distinct sub-cellular localisation during cell cycle phases. During mitosis, 4.1R is implicated in cell cycle progression and spindle pole formation, and co-localizes with NuMA1. However, during interphase 4.1R is located in the nucleus and only partially co-localizes with NuMA1. Results We have characterized by NMR the structural features of the C-terminal domain of 4.1R and those of the minimal region (the last 64 residues involved in the interaction with NuMA1. This subdomain behaves as an intrinsically unfolded protein containing a central region with helical tendency. The specific residues implicated in the interaction with NuMA1 have been mapped by NMR titrations and involve the N-terminal and central helical regions. The segment of NuMA1 that interacts with 4.1R is phosphorylated during mitosis. Interestingly, NMR data indicates that the phosphorylation of NuMA1 interacting peptide provokes a change in the interaction mechanism. In this case, the recognition occurs through the central helical region as well as through the C-terminal region of the subdomain meanwhile the N-terminal region do not interact. Conclusions These changes in the interaction derived from the phosphorylation state of NuMA1 suggest that phosphorylation can act as subtle mechanism of temporal and spatial regulation of the complex 4.1R-NuMA1 and therefore of the processes where both proteins play a role.

Electron and VLF travel time differences for wave-particle interactions at L=4: Pt. 2

International Nuclear Information System (INIS)

Rash, J.P.S.; Scourfield, M.W.J.; Dougherty, M.K.

1984-01-01

The cyclotron resonance or gyroresonance interaction has been widely invoked as a generation mechanism for discrete VLF emissions and plasmaspheric hiss. This interaction involves electrons and VLF waves travelling in opposite directions along a geomagnetic field line. We examine, for an interaction region in the equatorial plane at L=4, the energy of the resonant electrons as a function of VLF wave frequency and ambient equatorial electron density. Then for two different spatial configurations of the interaction and two standard plasma distribution models we examine the difference in travel times to a ground-based observer in the Southern hemisphere for the electrons and waves taking part in the interaction. This difference in travel times is shown as a function of VLF wave frequency and equatorial electron density. The results, and their significance for observations of auroral electrons and VLF at Sanae, Antarctica, are discussed and compared with similar results for the Cerenkov interaction discussed in an earlier paper

Anaplasma phagocytophilum MSP4 and HSP70 Proteins Are Involved in Interactions with Host Cells during Pathogen Infection

Directory of Open Access Journals (Sweden)

Marinela Contreras

2017-07-01

Full Text Available Anaplasma phagocytophilum transmembrane and surface proteins play a role during infection and multiplication in host neutrophils and tick vector cells. Recently, A. phagocytophilum Major surface protein 4 (MSP4 and Heat shock protein 70 (HSP70 were shown to be localized on the bacterial membrane, with a possible role during pathogen infection in ticks. In this study, we hypothesized that A. phagocytophilum MSP4 and HSP70 have similar functions in tick-pathogen and host-pathogen interactions. To address this hypothesis, herein we characterized the role of these bacterial proteins in interaction and infection of vertebrate host cells. The results showed that A. phagocytophilum MSP4 and HSP70 are involved in host-pathogen interactions, with a role for HSP70 during pathogen infection. The analysis of the potential protective capacity of MSP4 and MSP4-HSP70 antigens in immunized sheep showed that MSP4-HSP70 was only partially protective against pathogen infection. This limited protection may be associated with several factors, including the recognition of non-protective epitopes by IgG in immunized lambs. Nevertheless, these antigens may be combined with other candidate protective antigens for the development of vaccines for the control of human and animal granulocytic anaplasmosis. Focusing on the characterization of host protective immune mechanisms and protein-protein interactions at the host-pathogen interface may lead to the discovery and design of new effective protective antigens.

Azimuthal correlations in anti pp interactions at 22.4 GeV/c

International Nuclear Information System (INIS)

Reimer, P.

Data are presented on azimuthal two particle correlations and the effect is estimated of resonance production on these correlations in anti pp interactions at 22.4 GeV/c. Attention is paid to correlations between two charged pions produced in the process anti p+p→ two charged pions + anything. The dependence is described of the azimuthal asymmetry parameter on rapidity difference. (Z.J.)

Multi-domain CGFS-type glutaredoxin Grx4 regulates iron homeostasis via direct interaction with a repressor Fep1 in fission yeast

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyoung-Dong; Kim, Hyo-Jin; Lee, Kyung-Chang [Laboratory of Molecular Microbiology, School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742 (Korea, Republic of); Roe, Jung-Hye, E-mail: jhroe@snu.ac.kr [Laboratory of Molecular Microbiology, School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742 (Korea, Republic of)

2011-05-20

Research highlights: {yields} Monothiol glutaredoxin Grx4 allows Fep1-mediated de-repression of iron uptake genes at low iron. {yields} Grx4 directly interacts with Fep1 in vivo and in vitro. {yields} The Cys172 in the CGFS motif of Grx4 is necessary for cell proliferation and iron regulation. {yields} The Cys172 of Grx4 is required for normal interaction with Fep1. -- Abstract: The fission yeast Schizosaccharomyces pombe contains two CGFS-type monothiol glutaredoxins, Grx4 and Grx5, which are localized primarily in the nucleus and mitochondria, respectively. We observed involvement of Grx4 in regulating iron-responsive gene expression, which is modulated by a repressor Fep1. Lack of Grx4 caused defects not only in growth but also in the expression of both iron-uptake and iron-utilizing genes regardless of iron availability. In order to unravel how Grx4 is involved in Fep1-mediated regulation, interaction between them was investigated. Co-immunoprecipitation and bimolecular fluorescence complementation (BiFC) revealed that Grx4 physically interacts with Fep1 in vivo. BiFC revealed localized nuclear dots produced by interaction of Grx4 with Fep1. Mutation of cysteine-172 in the CGFS motif to serine (C172S) produced effects similarly observed under Grx4 depletion, such as the loss of iron-dependent gene regulation and the absence of nuclear dots in BiFC analysis. These results suggest that the ability of Grx4 to bind iron, most likely Fe-S cofactor, could be critical in interacting with and modulating the activity of Fep1.

Inhibition of Glycogen Synthase Kinase or the Apoptotic Protein p53 Lowers the Threshold of Helium Cardioprotection In Vivo: The Role of Mitochondrial Permeability Transition

Science.gov (United States)

Pagel, Paul S.; Krolikowski, John G.; Pratt, Phillip F.; Shim, Yon Hee; Amour, Julien; Warltier, David C.; Weihrauch, Dorothee

2008-01-01

BACKGROUND Prosurvival signaling kinases inhibit glycogen synthase kinase-3β (GSK-3β) activity and stimulate apoptotic protein p53 degradation. Helium produces cardioprotection by activating prosurvival kinases, but whether GSK and p53 inhibition mediate this process is unknown. We tested the hypothesis that inhibition of GSK or p53 lowers the threshold of helium cardioprotection via a mitochondrial permeability transition pore (mPTP)-dependent mechanism. METHODS Rabbits (n = 85) instrumented for hemodynamic measurement and subjected to a 30 min left anterior descending coronary artery (LAD) occlusion and 3 h reperfusion received 0.9% saline (control), or 1, 3, or 5 cycles of 70% helium-30% oxygen administered for 5 min interspersed with 5 min of an air-oxygen mixture (fraction of inspired oxygen concentration = 0.30) before LAD occlusion. Other rabbits received the GSK inhibitor SB 216763 (SB21; 0.2 or 0.6 mg/kg), the p53 inhibitor pifithrin-α (PIF; 1.5 or 3.0 mg/kg), or SB21 (0.2 mg/kg) or PIF (1.5 mg/kg) plus helium (1 cycle) before LAD occlusion in the presence or absence of the mPTP opener atractyloside (5 mg/kg). RESULTS Helium reduced (P < 0.05) myocardial infarct size (35 ± 6 [n = 7], 25 ± 4 [n = 7], and 20 ± 3% [n = 6] of area at risk, 1, 3, and 5 cycles, respectively) compared with control (44 ± 6% [n = 7]). SB21 (0.6 [n = 7] but not 0.2 mg/kg [n = 6]) and PIF (3.0 [n = 6] but not 1.5 mg/kg [n = 7]) also reduced necrosis. SB21 (0.2 mg/kg) or 1.5 mg/kg PIF (1.5 mg/kg) plus helium (1 cycle; n = 6 per group) decreased infarct size to an equivalent degree as three cycles of helium alone, and this cardioprotection was blocked by atractyloside (n = 7 per group). CONCLUSIONS Inhibition of GSK or p53 lowers the threshold of helium-induced preconditioning via a mPTP-dependent mechanism in vivo. PMID:18713881

Sapovirus translation requires an interaction between VPg and the cap binding protein eIF4E.

Science.gov (United States)

Hosmillo, Myra; Chaudhry, Yasmin; Kim, Deok-Song; Goodfellow, Ian; Cho, Kyoung-Oh

2014-11-01

Sapoviruses of the Caliciviridae family of small RNA viruses are emerging pathogens that cause gastroenteritis in humans and animals. Molecular studies on human sapovirus have been hampered due to the lack of a cell culture system. In contrast, porcine sapovirus (PSaV) can be grown in cell culture, making it a suitable model for understanding the infectious cycle of sapoviruses and the related enteric caliciviruses. Caliciviruses are known to use a novel mechanism of protein synthesis that relies on the interaction of cellular translation initiation factors with the virus genome-encoded viral protein genome (VPg) protein, which is covalently linked to the 5' end of the viral genome. Using PSaV as a representative member of the Sapovirus genus, we characterized the role of the viral VPg protein in sapovirus translation. As observed for other caliciviruses, the PSaV genome was found to be covalently linked to VPg, and this linkage was required for the translation and the infectivity of viral RNA. The PSaV VPg protein was associated with the 4F subunit of the eukaryotic translation initiation factor (eIF4F) complex in infected cells and bound directly to the eIF4E protein. As has been previously demonstrated for feline calicivirus, a member of the Vesivirus genus, PSaV translation required eIF4E and the interaction between eIF4E and eIF4G. Overall, our study provides new insights into the novel mechanism of sapovirus translation, suggesting that sapovirus VPg can hijack the cellular translation initiation mechanism by recruiting the eIF4F complex through a direct eIF4E interaction. Sapoviruses, which are members of the Caliciviridae family, are one of the causative agents of viral gastroenteritis in humans. However, human sapovirus remains noncultivable in cell culture, hampering the ability to characterize the virus infectious cycle. Here, we show that the VPg protein from porcine sapovirus, the only cultivatable sapovirus, is essential for viral translation and

Investigation of the Cry4B-prohibitin interaction in Aedes aegypti cells.

Science.gov (United States)

Kuadkitkan, Atichat; Smith, Duncan R; Berry, Colin

2012-10-01

Bacillus thuringiensis (Bt) produces insecticidal toxins active against insects. Cry4B, one of the major insecticidal toxins produced by Bt subsp. israelensis, is highly toxic to mosquitoes in the genus Aedes: the major vectors of dengue, yellow fever, and chikungunya. Previous work has shown that Cry4B binds to several mid-gut membrane proteins in Aedes aegypti larvae including prohibitin, a protein recently identified as a receptor that also mediates entry of dengue virus into Aedes cells. This study confirms the interaction between Cry4B and prohibitin by co-immunoprecipitation analysis and demonstrates colocalization of prohibitin and Cry4B by confocal microscopy. While activated Cry4B toxin showed high larvicidal activity, it was not cytotoxic to two Aedes cell lines, allowing determination of its effect on dengue virus infectivity in the absence of Cry4B-induced cell lysis. Pre-exposure of Aedes cells to Cry4B resulted in a significant reduction in the number of infected cells compared to untreated cells.

Induction of hepatic protein synthesis by a peptide in blood plasma of patients with sepsis and trauma.

Science.gov (United States)

Loda, M; Clowes, G H; Dinarello, C A; George, B C; Lane, B; Richardson, W

1984-08-01

Accelerated release of amino acids from muscle and their uptake for protein synthesis by liver and other visceral tissues are characteristic of trauma or sepsis. Experimentally, this response is induced by interleukin-1 (IL-1) generated by activated macrophages in vitro. However, IL-1 has not been demonstrated in human blood. A small 4000-dalton peptide recently isolated from plasma of patients with sepsis and trauma induces muscle proteolysis and is called "proteolysis-inducing factor" (PIF). To test whether this agent has the ability also to induce hepatic protein synthesis, a series of animal experiments and clinical observations were undertaken. The structural and secretory (acute-phase reactants) in vitro protein synthesis in livers of normal rats injected intraperitoneally with IL-1 or PIF was significantly greater than that of normal rats or those injected with Ringer's lactate (p less than 0.01). In patients with sepsis and trauma the central plasma clearance rate of amino acids, a measure of visceral (principally hepatic) amino acid uptake, was elevated and correlated with the rates of protein synthesis in incubated liver slices obtained by biopsy at operation from the same patients (p less than 0.05). Both in vivo measured central plasma clearance rate of amino acids and in vitro measured hepatic protein synthesis correlated with plasma levels of PIF in the same patients (p less than 0.01 and p less than 0.05, respectively). We conclude that since PIF, and not IL-1, is present in human plasma and both are produced by activated macrophages, PIF seems to be the stable circulating cleavage product of IL-1, which induces not only muscle proteolysis but also hepatic protein synthesis, principally in the form of acute-phase reactants during infection and other states in which inflammation is present.

Observation of Collective flow in interactions of 4.1(4.5) A GeV/c 22Ne(28Si) with Ag(Br)

International Nuclear Information System (INIS)

El-Naghy, A.; Fakhraddin, S.

2000-01-01

The study of the transverse momentum analysis and the angle of flow analysis lead to the observation of the side ward flow of the nuclear matter in the interactions of 4.1(4.5) 22 Ne( 28 Si) with Ag(Br). The distribution of the angle between the resultant vectors of the projectile and the target fragments showed a strong correlation between them in the azimuthal plane

INTERACTIONS OF THE INFRARED BUBBLE N4 WITH ITS SURROUNDINGS

Energy Technology Data Exchange (ETDEWEB)

Liu, Hong-Li; Li, Jin-Zeng; Yuan, Jing-Hua; Huang, Maohai; Huang, Ya-Fang; Zhang, Si-Ju [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Wu, Yuefang [Department of Astronomy, Peking University, 100871 Beijing (China); Liu, Tie [Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of); Dubner, G.; Paron, S.; Ortega, M. E. [1Instituto de Astronomía y Física del Espacio (IAFE, CONICET-UBA), CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Molinari, Sergio [Istituto di Astrofisica e Planetologia Spaziali—IAPS, Istituto Nazionale di Astrofisica—INAF, via Fosso del Cavaliere 100, I-00133 Roma (Italy); Zavagno, Annie; Samal, Manash R., E-mail: hlliu@nao.cas.cn [Aix Marseille Universit, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France)

2016-02-10

The physical mechanisms that induce the transformation of a certain mass of gas in new stars are far from being well understood. Infrared bubbles associated with H ii regions have been considered to be good samples for investigating triggered star formation. In this paper we report on the investigation of the dust properties of the infrared bubble N4 around the H ii region G11.898+0.747, analyzing its interaction with its surroundings and star formation histories therein, with the aim of determining the possibility of star formation triggered by the expansion of the bubble. Using Herschel PACS and SPIRE images with a wide wavelength coverage, we reveal the dust properties over the entire bubble. Meanwhile, we are able to identify six dust clumps surrounding the bubble, with a mean size of 0.50 pc, temperature of about 22 K, mean column density of 1.7 × 10{sup 22} cm{sup −2}, mean volume density of about 4.4 × 10{sup 4} cm{sup −3}, and a mean mass of 320 M{sub ⊙}. In addition, from PAH emission seen at 8 μm, free–free emission detected at 20 cm, and a probability density function in special regions, we could identify clear signatures of the influence of the H ii region on the surroundings. There are hints of star formation, though further investigation is required to demonstrate that N4 is the triggering source.

Mass and energy-capital conservation equations to study the price evolution of non-renewable energy resources

International Nuclear Information System (INIS)

Gori, F.

2006-01-01

Mass conservation equation of non-renewable resources is employed to study the resources remaining in the reservoir according to the extraction policy. The energy conservation equation is transformed into an energy-capital conservation equation. The Hotelling rule is shown to be a special case of the general energy-capital conservation equation when the mass flow rate of extracted resources is equal to unity. Mass and energy-capital conservation equations are then coupled and solved together. It is investigated the price evolution of extracted resources. The conclusion of the Hotelling rule for non-extracted resources, i.e. an exponential increase of the price of non-renewable resources at the rate of current interest, is then generalized. A new parameter, called 'Price Increase Factor', PIF, is introduced as the difference between the current interest rate of capital and the mass flow rate of extraction of non-renewable resources. The price of extracted resources can increase exponentially only if PIF is greater than zero or if the mass flow rate of extraction is lower than the current interest rate of capital. The price is constant if PIF is zero or if the mass flow rate of extraction is equal to the current interest rate. The price is decreasing with time if PIF is smaller than zero or if the mass flow rate of extraction is higher than the current interest rate. (author)

Pastern recognition of clusters formed in 4.1(4.5)A GeV/c 22Ne(28Si) interaction with emulsion using Lobachevsky velocity space

International Nuclear Information System (INIS)

EI-Naghy, A.; AbdeI-Aziz, S.S.; Salah, M.M.

2000-01-01

The experimental data of 4.1(4.5)A GeV/c 22 Ne( 28 Si) emulsion interactions, which has been measured in the laboratory of high energy physics ( LHEP ) at Cairo University , has been utilized in this analysis. In the present paper we propose the use of Bubelev's graphical method to visualize the candidates of cluster formation in nucleus - nucleus interactions. This method is based on the Chernikov geometry formulation of relativistic kinematics in patterns in the Lobachevsky velocity space in which the motion of particles are equivalent to the Lorentz group. The analysis has shown that events which are identified as formation of clusters in 22 Ne( 28 Si) emulsion interactions are well illustrated in the Lobachevsky velocity space using the principle of likeness (closeness). The study will be extended to include other reactions and other types of particles

Analysis of thermoluminescence kinetics of Mg2SiO4:Tb compounds employing an interactive model

International Nuclear Information System (INIS)

Marcazzo, J.; Prokic, M.; Santiago, M.; Molina, P.; Caselli, E.

2009-01-01

The kinetics involved in the thermoluminescence (TL) of Mg 2 SiO 4 :Tb compounds has been investigated by unfolding glow curves employing both the General Order model and a model that takes into account interactions among traps. The dependence of the glow curve shape on dose is only correctly described if interaction among traps is included in the analysis.

Effect of the final-state interaction on the initial core-hole lifetime: the case of the 4s-hole lifetime of Sn metal

International Nuclear Information System (INIS)

Ohno, Masahide

2003-01-01

The first theoretical study of the effect of the final-state interaction on the initial core-hole lifetime is presented. The 4s-hole lifetime width of Sn metal is calculated by an ab-initio atomic many-body theory (Green's function method). When the final-state interaction in the 4p4d two-hole state, created by the 4s -1 -4p -1 4d -1 εf super Coster-Kronig (CK) transition of the initial 4s hole, is explicitly taken into account, the ab-initio atomic many-body calculation of the 4s-hole X-ray photoelectron spectroscopy (XPS) spectrum of Sn atom can provide excellent agreement with experiment in both the 4s-hole energy and the 4s-hole lifetime width. Otherwise, the many-body calculation underestimates considerably the 4s-hole lifetime width. The 4p4d two-hole state interacts strongly with the 4d triple-hole state by the 4p -1 4d -1 -4d -3 εf super CK transition. The interaction affects greatly the initial 4s-hole lifetime width

Peritonitis infecciosa felina, gastroenteritis y colangiohepatitis parasitaria (platinosomiasis) con colangiocarcinoma hepático: estudio clínico y anatomopatológico de tres casos

OpenAIRE

Vale Echeto, Oswaldo E.; Madrigal, Karina; Admadé, María; Vale Oviedo, Oswaldo R.; Moreno, Alejandro; Simoes, David

2009-01-01

La Peritonitis Infecciosa Felina (PIF) es una enfermedad viral sistémica producida por un coronavirus (ARN) que ocurre con frecuencia en los felinos domésticos. Este proceso patológico ha sido referido en el felino doméstico y relacionado concurrentemente con otras enfermedades virales tales como la panleucopenia felina, leucemia felina y enteritis por coronavirus. En el presente trabajo se reportan los hallazgos clínicos y anatomopatológicos de tres casos de PIF, asociados a gastroenteritis ...

Measurement of 19F nucleus interaction at 4 GeV/c per nucleon

International Nuclear Information System (INIS)

Golovin, V.M.; Golutvin, I.A.; Dolya, S.N.

1986-01-01

The cross sections of 19 F nucleus interaction with the nuclei of different elements at 4 GeV/c x nucleon momentum in reactions are measured. In the finite state of these reactions the fragment with charge Z≤8 is formed. The experiment apparatus comprises a transmission detector where the nuclei trajectory at the target input has been measured with proportional chambers whereas the nuclear charge before and after the target has been measured by Cherenkov counters. Experimental data obtained with accuracy - 2% are presented for carbon, aluminium, copper, indium, tungsten, bismuth and uranium targets. The dependence of cross sections on atomic number of the target coincides except of cross section of interaction with heavy targets

Interaction cross sections and pions minus multiplicities on nucleus-nucleus collisions at 4.2 GeV/c per nucleon

International Nuclear Information System (INIS)

Angelov, N.; Ahababyan, N.; Anoshin, A.I.

1979-01-01

Data are presented on inelastic cross sections and multiplicities of pions minus produced on collisions of protons, deuterons, helium-4 and carbon-12 nuclei at 4.2 GeV/c per nucleon in the propane bubble chamber witn tantalum and carbon plates. Average multiplicities and dispersions of multiplicity distributions are compared with those in nucleon-nucleon interactions. Deviation of C-Ta interaction data from universal dependence of dispersion on multiplicity is observed. Pion multiplicities are found proportional to the number of nucleons from incident nucleus which interacted in the target. The results are not in contradiction with the assumption that nucleons from the incident nucleus interact independently in the target. For C-Ta interactions the average radius of the pion emission volume has been determined by the interference method to be r=(3.3+-0.6) fm

Identification of a functional interaction between Kv4.3 channels and c-Src tyrosine kinase.

Science.gov (United States)

Gomes, Pedro; Saito, Tomoaki; Del Corsso, Cris; Alioua, Abderrahmane; Eghbali, Mansoureh; Toro, Ligia; Stefani, Enrico

2008-10-01

Voltage-gated K(+) (Kv) channels are key determinants of cardiac and neuronal excitability. A substantial body of evidence has accumulated in support of a role for Src family tyrosine kinases in the regulation of Kv channels. In this study, we examined the possibility that c-Src tyrosine kinase participates in the modulation of the transient voltage-dependent K(+) channel Kv4.3. Supporting a mechanistic link between Kv4.3 and c-Src, confocal microscopy analysis of HEK293 cells stably transfected with Kv4.3 showed high degree of co-localization of the two proteins at the plasma membrane. Our results further demonstrate an association between Kv4.3 and c-Src by co-immunoprecipitation and GST pull-down assays, this interaction being mediated by the SH2 and SH3 domains of c-Src. Furthermore, we show that Kv4.3 is tyrosine phosphorylated under basal conditions. The functional relevance of the observed interaction between Kv4.3 and c-Src was established in patch-clamp experiments, where application of the Src inhibitor PP2 caused a decrease in Kv4.3 peak current amplitude, but not the inactive structural analogue PP3. Conversely, intracellular application of recombinant c-Src kinase or the protein tyrosine phosphatase inhibitor bpV(phen) increased Kv4.3 peak current amplitude. In conclusion, our findings provide evidence that c-Src-induced Kv4.3 channel activation involves their association in a macromolecular complex and suggest a role for c-Src-Kv4.3 pathway in regulating cardiac and neuronal excitability.

A computational study of magnetic exchange interactions of 3d and 4f electrons in Ti-Ce co-doped AlN

Energy Technology Data Exchange (ETDEWEB)

Majid, Abdul, E-mail: abdulmajid40@yahoo.com [Department of Physics, University of Gujrat, Gujrat (Pakistan); Department of Adaptive Machine Systems, Osaka University, Osaka (Japan); Azmat, Mian [Department of Physics, University of Gujrat, Gujrat (Pakistan); Rana, Usman Ali; Khan, Salah Ud-Din [Sustainable Energy Technologies Center, College of Engineering, King Saud University, PO-Box 800, Riyadh 11421 (Saudi Arabia); Alzahrani, Eman [Department of Chemistry, Faculty of Science, Taif University, 888 Taif (Saudi Arabia)

2016-08-15

To investigate the nature of 3d-4f exchange interactions in III-Nitride semiconductors, Ti-Ce co-doped AlN were studied using first principles calculations. The calculations were performed using supercell approach with varying dopant concentration and different inter-dopant separation. The configuration with dopant located as nearest neighbor distance and diluted concentration of 3.125% was found most stable. The results exhibited prominent evidence of 3d-4f-5d strong hybridization suggesting 3d-4f direct exchange interactions which may play valuable role to exploit the system as high Curie temperature ferromagnetic semiconductors for use in spintronics. Moreover, metal to metal charge transfer was also observed in the materials which may be exploited for their use in electrochemical applications. The 4f-5d and 3d-5d hybridizations were observed that predicts excellent luminescence phenomena in the materials. The presence of impurity related deep intermediate bands suggest applications of the materials in opto-electronic and spintronics devices. - Highlights: • Double exchange interaction in Ti:AlN. • Impurity induced narrowing of band gap. • Superexchange interaction in Ce:AlN. • 3d-4f exchange interaction between Ti-3d and Ce-4f states. • High Curie temperature n-type ferromagnetic semiconductors.

A computational study of magnetic exchange interactions of 3d and 4f electrons in Ti-Ce co-doped AlN

International Nuclear Information System (INIS)

Majid, Abdul; Azmat, Mian; Rana, Usman Ali; Khan, Salah Ud-Din; Alzahrani, Eman

2016-01-01

To investigate the nature of 3d-4f exchange interactions in III-Nitride semiconductors, Ti-Ce co-doped AlN were studied using first principles calculations. The calculations were performed using supercell approach with varying dopant concentration and different inter-dopant separation. The configuration with dopant located as nearest neighbor distance and diluted concentration of 3.125% was found most stable. The results exhibited prominent evidence of 3d-4f-5d strong hybridization suggesting 3d-4f direct exchange interactions which may play valuable role to exploit the system as high Curie temperature ferromagnetic semiconductors for use in spintronics. Moreover, metal to metal charge transfer was also observed in the materials which may be exploited for their use in electrochemical applications. The 4f-5d and 3d-5d hybridizations were observed that predicts excellent luminescence phenomena in the materials. The presence of impurity related deep intermediate bands suggest applications of the materials in opto-electronic and spintronics devices. - Highlights: • Double exchange interaction in Ti:AlN. • Impurity induced narrowing of band gap. • Superexchange interaction in Ce:AlN. • 3d-4f exchange interaction between Ti-3d and Ce-4f states. • High Curie temperature n-type ferromagnetic semiconductors.

CD4-binding site alterations in CCR5-using HIV-1 envelopes influencing gp120-CD4 interactions and fusogenicity

International Nuclear Information System (INIS)

Sterjovski, Jasminka; Churchill, Melissa J.; Roche, Michael; Ellett, Anne; Farrugia, William; Wesselingh, Steven L.; Cunningham, Anthony L.; Ramsland, Paul A.; Gorry, Paul R.

2011-01-01

CD4-binding site (CD4bs) alterations in gp120 contribute to different pathophysiological phenotypes of CCR5-using (R5) HIV-1 strains, but the potential structural basis is unknown. Here, we characterized functionally diverse R5 envelope (Env) clones (n = 16) to elucidate potential structural alterations within the gp120 CD4bs that influence Env function. Initially, we showed that the magnitude of gp120-CD4-binding correlates with increased fusogenicity and reduced CD4 dependence. Analysis of three-dimensional gp120 structural models revealed two CD4bs variants, D279 and N362, that were associated with reduced CD4 dependence. Further structural analysis showed that a wider aperture of the predicted CD4bs cavity, as constrained by the inner-most atoms at the gp120 V1V2 stem and the V5 loop, was associated with amino acid alterations within V5 and correlated with increased gp120-CD4 binding and increased fusogenicity. Our results provide evidence that the gp120 V5 loop may alter CD4bs conformation and contribute to increased gp120-CD4 interactions and Env fusogenicity.

High-Affinity Interaction of the K-Ras4B Hypervariable Region with the Ras Active Site

Science.gov (United States)

Chavan, Tanmay S.; Jang, Hyunbum; Khavrutskii, Lyuba; Abraham, Sherwin J.; Banerjee, Avik; Freed, Benjamin C.; Johannessen, Liv; Tarasov, Sergey G.; Gaponenko, Vadim; Nussinov, Ruth; Tarasova, Nadya I.

2015-01-01

Ras proteins are small GTPases that act as signal transducers between cell surface receptors and several intracellular signaling cascades. They contain highly homologous catalytic domains and flexible C-terminal hypervariable regions (HVRs) that differ across Ras isoforms. KRAS is among the most frequently mutated oncogenes in human tumors. Surprisingly, we found that the C-terminal HVR of K-Ras4B, thought to minimally impact the catalytic domain, directly interacts with the active site of the protein. The interaction is almost 100-fold tighter with the GDP-bound than the GTP-bound protein. HVR binding interferes with Ras-Raf interaction, modulates binding to phospholipids, and slightly slows down nucleotide exchange. The data indicate that contrary to previously suggested models of K-Ras4B signaling, HVR plays essential roles in regulation of signaling. High affinity binding of short peptide analogs of HVR to K-Ras active site suggests that targeting this surface with inhibitory synthetic molecules for the therapy of KRAS-dependent tumors is feasible. PMID:26682817

[Intraabdominal fat redistribution in long-term continuous positive airway pressure treatment in obstructive sleep apnea patients].

Science.gov (United States)

Català, Raquel; Ferré, Raimón; Sangenís, Sandra; Cabré, Anna; Hernández-Flix, Salvador; Masana, Lluís

2016-06-03

Obesity is the main risk factor for obstructive sleep apnoea (OSA). The aim was to evaluate the long-term effect of continuous positive airway pressure (CPAP) on intraabdominal fat distribution in OSA patients. Fifty OSA patients with and 35 without CPAP treatment criteria were followed-up for 2 years. Visceral and subcutaneous adipose tissue (VAT and SAT) and preaortic intraabdominal fat (PIF) were assessed by sonography. In the non CPAP treated group, SAT and VAT mean values didn't change, while a significantly PIF growth was observed (55.19 [23.44] vs. 63.45 [23.94] mm, P=.021). In the CPAP treated group, VAT and PIF mean were not changed, while SAT decreased significantly (11.29 [5.69] vs. 10.47 [5.71] mm, P=.012). Long-term CPAP treatment produces intraabdominal fat redistribution and is associated with an anthropometric profile of lower cardiovascular risk in OSA patients. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

The CCR4-NOT complex physically and functionally interacts with TRAMP and the nuclear exosome.

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Nowel Azzouz

Full Text Available BACKGROUND: Ccr4-Not is a highly conserved multi-protein complex consisting in yeast of 9 subunits, including Not5 and the major yeast deadenylase Ccr4. It has been connected functionally in the nucleus to transcription by RNA polymerase II and in the cytoplasm to mRNA degradation. However, there has been no evidence so far that this complex is important for RNA degradation in the nucleus. METHODOLOGY/PRINCIPAL FINDINGS: In this work we point to a new role for the Ccr4-Not complex in nuclear RNA metabolism. We determine the importance of the Ccr4-Not complex for the levels of non-coding nuclear RNAs, such as mis-processed and polyadenylated snoRNAs, whose turnover depends upon the nuclear exosome and TRAMP. Consistently, mutation of both the Ccr4-Not complex and the nuclear exosome results in synthetic slow growth phenotypes. We demonstrate physical interactions between the Ccr4-Not complex and the exosome. First, Not5 co-purifies with the exosome. Second, several exosome subunits co-purify with the Ccr4-Not complex. Third, the Ccr4-Not complex is important for the integrity of large exosome-containing complexes. Finally, we reveal a connection between the Ccr4-Not complex and TRAMP through the association of the Mtr4 helicase with the Ccr4-Not complex and the importance of specific subunits of Ccr4-Not for the association of Mtr4 with the nuclear exosome subunit Rrp6. CONCLUSIONS/SIGNIFICANCE: We propose a model in which the Ccr4-Not complex may provide a platform contributing to dynamic interactions between the nuclear exosome and its co-factor TRAMP. Our findings connect for the first time the different players involved in nuclear and cytoplasmic RNA degradation.

Interaction of silicene with β-Si3N4(0001)/Si(111) substrate; energetics and electronic properties

International Nuclear Information System (INIS)

Filippone, Francesco

2014-01-01

The free-standing, quasi-2D layer of Si is known as silicene, in analogy with graphene. Much effort is devoted in the study of silicene, since, similarly to graphene, it shows a very high electron mobility. The interaction of silicene with a hybrid substrate, β-Si 3 N 4 (0001)/Si(111), exposing the β-Si 3 N 4 (0001) surface, has been studied by means of Density Functional calculations, with van der Waals interactions included. Once deepened the most important structural and electronic features of the hybrid substrate, we demonstrated that an electron transfer occurs from the substrate to the silicene layer. In turn, such an electron transfer can be modulated by the doping of the substrate. The β-Si 3 N 4 /silicene interaction appears to be strong enough to ensure adequate adsorption stability. It is also shown that electronic states of substrate and adsorbate still remain decoupled, paving the way for the exploitation of the peculiar electron mobility properties of the silicene layer. A detailed analysis in both direct and reciprocal space is reported. (paper)

Interaction between NANOS2 and the CCR4-NOT Deadenylation Complex Is Essential for Male Germ Cell Development in Mouse

OpenAIRE

Suzuki, Atsushi; Saba, Rie; Miyoshi, Kei; Morita, Yoshinori; Saga, Yumiko

2012-01-01

Nanos is one of the evolutionarily conserved proteins implicated in germ cell development and we have previously shown that it interacts with the CCR4-NOT deadenylation complex leading to the suppression of specific RNAs. However, the molecular mechanism and physiological significance of this interaction have remained elusive. In our present study, we identify CNOT1, a component of the CCR4-NOT deadenylation complex, as a direct factor mediating the interaction with NANOS2. We find that the f...

S100A9 interaction with TLR4 promotes tumor growth.

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Eva Källberg

Full Text Available By breeding TRAMP mice with S100A9 knock-out (S100A9(-/- animals and scoring the appearance of palpable tumors we observed a delayed tumor growth in animals devoid of S100A9 expression. CD11b(+ S100A9 expressing cells were not observed in normal prostate tissue from control C57BL/6 mice but were readily detected in TRAMP prostate tumors. Also, S100A9 expression was observed in association with CD68(+ macrophages in biopsies from human prostate tumors. Delayed growth of TRAMP tumors was also observed in mice lacking the S100A9 ligand TLR4. In the EL-4 lymphoma model tumor growth inhibition was observed in S100A9(-/- and TLR4(-/-, but not in RAGE(-/- animals lacking an alternative S100A9 receptor. When expression of immune-regulating genes was analyzed using RT-PCR the only common change observed in mice lacking S100A9 and TLR4 was a down-regulation of TGFβ expression in splenic CD11b(+ cells. Lastly, treatment of mice with a small molecule (ABR-215050 that inhibits S100A9 binding to TLR4 inhibited EL4 tumor growth. Thus, S100A9 and TLR4 appear to be involved in promoting tumor growth in two different tumor models and pharmacological inhibition of S100A9-TLR4 interactions is a novel and promising target for anti-tumor therapies.

S100A9 Interaction with TLR4 Promotes Tumor Growth

Science.gov (United States)

Källberg, Eva; Vogl, Thomas; Liberg, David; Olsson, Anders; Björk, Per; Wikström, Pernilla; Bergh, Anders; Roth, Johannes; Ivars, Fredrik; Leanderson, Tomas

2012-01-01

By breeding TRAMP mice with S100A9 knock-out (S100A9−/−) animals and scoring the appearance of palpable tumors we observed a delayed tumor growth in animals devoid of S100A9 expression. CD11b+ S100A9 expressing cells were not observed in normal prostate tissue from control C57BL/6 mice but were readily detected in TRAMP prostate tumors. Also, S100A9 expression was observed in association with CD68+ macrophages in biopsies from human prostate tumors. Delayed growth of TRAMP tumors was also observed in mice lacking the S100A9 ligand TLR4. In the EL-4 lymphoma model tumor growth inhibition was observed in S100A9−/− and TLR4−/−, but not in RAGE−/− animals lacking an alternative S100A9 receptor. When expression of immune-regulating genes was analyzed using RT-PCR the only common change observed in mice lacking S100A9 and TLR4 was a down-regulation of TGFβ expression in splenic CD11b+ cells. Lastly, treatment of mice with a small molecule (ABR-215050) that inhibits S100A9 binding to TLR4 inhibited EL4 tumor growth. Thus, S100A9 and TLR4 appear to be involved in promoting tumor growth in two different tumor models and pharmacological inhibition of S100A9-TLR4 interactions is a novel and promising target for anti-tumor therapies. PMID:22470535

Targeting Hsp27/eIF4E interaction with phenazine compound: a promising alternative for castration-resistant prostate cancer treatment.

Science.gov (United States)

Hajer, Ziouziou; Claudia, Andrieu; Erik, Laurini; Sara, Karaki; Maurizio, Fermeglia; Ridha, Oueslati; David, Taieb; Michel, Camplo; Olivier, Siri; Sabrina, Pricl; Maria, Katsogiannou; Palma, Rocchi

2017-09-29

The actual strategy to improve current therapies in advanced prostate cancer involves targeting genes activated by androgen withdrawal, either to delay or prevent the emergence of the castration-refractory phenotype. However, these genes are often implicated in several physiological processes, and long-term inhibition of survival proteins might be accompanied with cytotoxic effects. To avoid this problem, an alternative therapeutic strategy relies on the identification and use of compounds that disrupt specific protein-protein interactions involved in androgen withdrawal. Specifically, the interaction of the chaperone protein Hsp27 with the initiation factor eIF4E leads to the protection of protein synthesis initiation process and enhances cell survival during cell stress induced by castration or chemotherapy. Thus, in this work we aimed at i) identifying the interaction site of the Hsp27/eIF4E complex and ii) interfere with the relevant protein/protein association mechanism involved in castration-resistant progression of prostate cancer. By a combination of experimental and modeling techniques, we proved that eIF4E interacts with the C-terminal part of Hsp27, preferentially when Hsp27 is phosphorylated. We also observed that the loss of this interaction increased cell chemo-and hormone-sensitivity. In order to find a potential inhibitor of Hsp27/eIF4E interaction, BRET assays in combination with molecular simulations identified the phenazine derivative 14 as the compound able to efficiently interfere with this protein/protein interaction, thereby inhibiting cell viability and increasing cell death in chemo- and castration-resistant prostate cancer models in vitro and in vivo .

Thermal solid-state Z/E isomerization of 2-alkylidene-4-oxothiazolidines: effects of non-covalent interactions

Directory of Open Access Journals (Sweden)

ZDRAVKO DŽAMBASKI

2011-03-01

Full Text Available Configurational isomerization of stereo-defined 5-substituted and unsubstituted 2-alkylidene-4-oxothiazolidines (1 in the solid state, giving the Z/E mixtures in various ratios, was investigated by 1H-NMR spectroscopy, X-ray powder crystallography and differential scanning calorimetry (DSC. The Z/E composition can be rationalized in terms of non-covalent interactions, involving intermolecular and intramolecular hydrogen bonding and directional non-bonded 1,5-type S×××O interactions. X-Ray powder crystallography, using selected crystalline (Z-4-oxothiazolidine substrates, revealed transformation to the amorphous state during the irreversible Z®E process. A correlation between previous results on the Z/E isomerization in solution and now in the solid state was established.

A PDZ-Like Motif in the Biliary Transporter ABCB4 Interacts with the Scaffold Protein EBP50 and Regulates ABCB4 Cell Surface Expression.

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Quitterie Venot

Full Text Available ABCB4/MDR3, a member of the ABC superfamily, is an ATP-dependent phosphatidylcholine translocator expressed at the canalicular membrane of hepatocytes. Defects in the ABCB4 gene are associated with rare biliary diseases. It is essential to understand the mechanisms of its canalicular membrane expression in particular for the development of new therapies. The stability of several ABC transporters is regulated through their binding to PDZ (PSD95/DglA/ZO-1 domain-containing proteins. ABCB4 protein ends by the sequence glutamine-asparagine-leucine (QNL, which shows some similarity to PDZ-binding motifs. The aim of our study was to assess the potential role of the QNL motif on the surface expression of ABCB4 and to determine if PDZ domain-containing proteins are involved. We found that truncation of the QNL motif decreased the stability of ABCB4 in HepG2-transfected cells. The deleted mutant ABCB4-ΔQNL also displayed accelerated endocytosis. EBP50, a PDZ protein highly expressed in the liver, strongly colocalized and coimmunoprecipitated with ABCB4, and this interaction required the QNL motif. Down-regulation of EBP50 by siRNA or by expression of an EBP50 dominant-negative mutant caused a significant decrease in the level of ABCB4 protein expression, and in the amount of ABCB4 localized at the canalicular membrane. Interaction of ABCB4 with EBP50 through its PDZ-like motif plays a critical role in the regulation of ABCB4 expression and stability at the canalicular plasma membrane.

Interaction of RECQ4 and MCM10 is important for efficient DNA replication origin firing in human cells

DEFF Research Database (Denmark)

Kliszczak, Maciej; Sedlackova, Hana; Pitchai, Ganesha P

2015-01-01

DNA replication is a highly coordinated process that is initiated at multiple replication origins in eukaryotes. These origins are bound by the origin recognition complex (ORC), which subsequently recruits the Mcm2-7 replicative helicase in a Cdt1/Cdc6-dependent manner. In budding yeast, two...... essential replication factors, Sld2 and Mcm10, are then important for the activation of replication origins. In humans, the putative Sld2 homolog, RECQ4, interacts with MCM10. Here, we have identified two mutants of human RECQ4 that are deficient in binding to MCM10. We show that these RECQ4 variants...... are able to complement the lethality of an avian cell RECQ4 deletion mutant, indicating that the essential function of RECQ4 in vertebrates is unlikely to require binding to MCM10. Nevertheless, we show that the RECQ4-MCM10 interaction is important for efficient replication origin firing....

Interaction of Munc18c and syntaxin4 facilitates invadopodium formation and extracellular matrix invasion of tumor cells.

Science.gov (United States)

Brasher, Megan I; Martynowicz, David M; Grafinger, Olivia R; Hucik, Andrea; Shanks-Skinner, Emma; Uniacke, James; Coppolino, Marc G

2017-09-29

Tumor cell invasion involves targeted localization of proteins required for interactions with the extracellular matrix and for proteolysis. The localization of many proteins during these cell-extracellular matrix interactions relies on membrane trafficking mediated in part by SNAREs. The SNARE protein syntaxin4 (Stx4) is involved in the formation of invasive structures called invadopodia; however, it is unclear how Stx4 function is regulated during tumor cell invasion. Munc18c is known to regulate Stx4 activity, and here we show that Munc18c is required for Stx4-mediated invadopodium formation and cell invasion. Biochemical and microscopic analyses revealed a physical association between Munc18c and Stx4, which was enhanced during invadopodium formation, and that a reduction in Munc18c expression decreases invadopodium formation. We also found that an N-terminal Stx4-derived peptide associates with Munc18c and inhibits endogenous interactions of Stx4 with synaptosome-associated protein 23 (SNAP23) and vesicle-associated membrane protein 2 (VAMP2). Furthermore, expression of the Stx4 N-terminal peptide decreased invadopodium formation and cell invasion in vitro Of note, cells expressing the Stx4 N-terminal peptide exhibited impaired trafficking of membrane type 1 matrix metalloproteinase (MT1-MMP) and EGF receptor (EGFR) to the cell surface during invadopodium formation. Our findings implicate Munc18c as a regulator of Stx4-mediated trafficking of MT1-MMP and EGFR, advancing our understanding of the role of SNARE function in the localization of proteins that drive tumor cell invasion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Interacting fields of arbitrary spin and N > 4 supersymmetric self-dual Yang-Mills equations

International Nuclear Information System (INIS)

Devchand, Ch.; Ogievetsky, V.

1996-06-01

We show that the self-dual Yang-Mills equations afford supersymmetrization to systems of equations invariant under global N-extended super-Poincare transformations for arbitrary values of N, without the limitation (N ≤ 4) applicable to standard non-self-dual Yang-Mills theories. These systems of equations provide novel classically consistent interactions for vector supermultiplets containing fields of spin up to N-2/2. The equations of motion of the component fields of spin greater than 1/2 are interacting variants of the first-order Dirac-Fierz equations for zero rest-mass fields of arbitrary spin. The interactions are governed by conserved currents which are constructed by an iterative procedure. In (arbitrarily extended) chiral superspace, the equations of motion for the (arbitrarily large) self-dual supermultiplet are shown to be completely equivalent to the set of algebraic supercurvature defining the self-dual superconnection. (author). 25 refs

Cell interaction with modified nanotubes formed on titanium alloy Ti-6Al-4V

Czech Academy of Sciences Publication Activity Database

Moravec, H.; Vandrovcová, Marta; Chotová, K.; Fojt, J.; Průchová, E.; Joska, L.; Bačáková, Lucie

2016-01-01

Roč. 65, Aug 1 (2016), s. 313-322 ISSN 0928-4931 R&D Projects: GA ČR(CZ) GA15-01558S Institutional support: RVO:67985823 Keywords : titanium * electrochemical oxidation * hydrothermal modification * thermal treatment * protein adsorption * cell interaction Subject RIV: EI - Biotechnology ; Bionics Impact factor: 4.164, year: 2016

Kinome profiling reveals an interaction between jasmonate, salicylate and light control of hyponastic petiole growth in Arabidopsis thaliana.

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Tita Ritsema

Full Text Available Plants defend themselves against infection by biotic attackers by producing distinct phytohormones. Especially jasmonic acid (JA and salicylic acid (SA are well known defense-inducing hormones. Here, the effects of MeJA and SA on the Arabidopsis thaliana kinome were monitored using PepChip arrays containing kinase substrate peptides to analyze posttranslational interactions in MeJA and SA signaling pathways and to test if kinome profiling can provide leads to predict posttranslational events in plant signaling. MeJA and SA mediate differential phosphorylation of substrates for many kinase families. Also some plant specific substrates were differentially phosphorylated, including peptides derived from Phytochrome A, and Photosystem II D protein. This indicates that MeJA and SA mediate cross-talk between defense signaling and light responses. We tested the predicted effects of MeJA and SA using light-mediated upward leaf movement (differential petiole growth also called hyponastic growth. We found that MeJA, infestation by the JA-inducing insect herbivore Pieris rapae, and SA suppressed low light-induced hyponastic growth. MeJA and SA acted in a synergistic fashion via two (partially divergent signaling routes. This work demonstrates that kinome profiling using PepChip arrays can be a valuable complementary ∼omics tool to give directions towards predicting behavior of organisms after a given stimulus and can be used to obtain leads for physiological relevant phenomena in planta.

4,4′-Bipyridinium bis(perchlorate–4-aminobenzoic acid–4,4′-bipyridine–water (1/4/2/2

Directory of Open Access Journals (Sweden)

Qun-Hui Meng

2009-01-01

Full Text Available In the structure of the title compound, C10H10N22+·2ClO4−·4C7H7NO2·2C10H8N2·2H2O, the 4,4′-bipyridinium cation has a crystallographically imposed centre of symmetry. The cation is linked by N—H...N hydrogen bonds to adjacent 4,4′-bipyridine molecules, which in turn interact via O—H...N hydrogen bonds with 4-aminobenzoic acid molecules, forming chains running parallel to [30overline{2}]. The chains are further connected into a three-dimensional network by N—H...O and O—H...O hydrogen-bonding interactions involving the perchlorate anion, the water molecules and the 4-aminobenzoic acid molecules. In addition, π–π stacking interactions with centroid–centroid distances ranging from 3.663 (6 to 3.695 (6 Å are present. The O atoms of the perchlorate anion are disordered over two sets of positions, with refined site occupancies of 0.724 (9 and 0.276 (9.

Mechanistic insights into the interaction between energetic oxygen ions and nanosized ZnFe2O4: XAS-XMCD investigations.

Science.gov (United States)

Singh, Jitendra Pal; Kaur, Baljeet; Sharma, Aditya; Kim, So Hee; Gautam, Sanjeev; Srivastava, Ramesh Chandra; Goyal, Navdeep; Lim, Weol Cheol; Lin, H-J; Chen, J M; Asokan, K; Kanjilal, D; Won, Sung Ok; Lee, Ik-Jae; Chae, Keun Hwa

2018-04-20

The interactions of energetic ions with multi-cation compounds and their consequences in terms of changes in the local electronic structure, which may facilitate intriguing hybridization between O 2p and metal d orbitals and magnetic ordering, are the subject of debate and require a deep understanding of energy transfer processes and magnetic exchange mechanisms. In this study, nanocrystals of ZnFe2O4 were exposed to O7+ ions with an energy of 100 MeV to understand, qualitatively and quantitatively, the metal-ligand field interactions, cation migration and magnetic exchange interactions by employing X-ray absorption fine structure measurements and X-ray magnetic circular dichroism to get deeper mechanistic insights. Nanosized zinc ferrite nanoparticles (NPs) with a size of ∼16 nm synthesized in the cubic spinel phase exhibited deterioration of the crystalline phase when 100 MeV O7+ ions passed through them. However, the size of these NPs remained almost the same. The behaviour of crystal deterioration is associated with the confinement of heat in this interaction. The energy confined inside the nanoparticles promotes cation redistribution as well as the modification of the local electronic structure. Prior to this interaction, almost 42% of Zn2+ ions occupied AO4 tetrahedra; however, this value increased to 63% after the interaction. An inverse effect was observed for metal ion occupancies in BO6 octahedra. The L-edge spectra of Fe and Zn reveal that the spin and valence states of the metal ions were not affected by this interaction. This effect is also supported by K-edge measurements for Fe and Zn. The t2g/eg intensity ratio in the O K-edge spectra decreased after this interaction, which is associated with detachment of Zn2+ ions from the lattice. The extent of hybridization, as estimated from the ratio of the post-edge to the pre-edge region of the O K-edge spectra, decreased after this interaction. The metal-oxygen and metal-metal bond lengths were modified

Systematics of bar Qq4 systems with a pure chromomagnetic interaction

International Nuclear Information System (INIS)

Leandri, J.; Silvestre-Brac, B.

1989-01-01

In the framework of a pure chromomagnetic Hamiltonian, we study all the states of bar Qq 4 systems allowed by the Pauli principle. The wave functions are analyzed by group-theoretical techniques in a first step where the antiquark has an infinite mass and the quarks belong to an SU(3) F multiplet. The breaking of these symmetries is performed exactly through two parameters η and δ. The emphasis is put on the corresponding energies relative to the physical thresholds in bar Qq+q 3 . We propose a number of new multiquarks which could be stable under strong interactions

Solid-solid interactions in Co3O4-MoO3/MgO system

International Nuclear Information System (INIS)

Radwan, Nagi R.E.; Ghozza, Ahmed M.; El-Shobaky, Gamil A.

2003-01-01

Cobalt/magnesium mixed oxide solids and cobalt-molybdenum/magnesium mixed oxide solids were prepared by thermal decomposition of basic magnesium carbonate pretreated with different proportions of cobalt nitrate and then with calculated amounts of ammonium molybdate. The proportions of cobalt expressed as Co 3 O 4 were 0.1, 0.2 and 0.3 mol while the concentrations of molybdenum expressed as mol% MoO 3 were 2.5 and 5.0. The prepared mixed solid specimens were calcined in air at 400-1000 deg. C. The solid-solid interactions in Co 3 O 4 -MoO 3 were investigated using DTA, TG and X-ray powder diffraction (XRD) techniques. The results obtained revealed that MgO dissolved cobalt oxide in its lattice forming CoO-MgO solid solution. The amount of cobalt dissolved increases by increasing the temperature in the range 800-1000 deg. C. This finding was confirmed by X-ray diffractograms in which all the diffraction lines of cobalt oxide disappeared at 1000 deg. C. MoO 3 present interacted readily with MgO and cobalt oxide by heat treatment at temperature starting from 400 deg. C producing MgMoO 4 and CoMoO 4 which remained stable by heating at 1000 deg. C. The impregnation of basic magnesium carbonate with cobalt nitrate much enhanced its thermal decomposition yielding MgO, which decomposed completely at 395.5 deg. C instead of 525 deg. C. The formation of magnesium cobaltite (MgCo 2 O 4 ) has been ruled out via XRD investigation at relatively high diffraction angles

Application of Lean Principles to Neurosurgical Procedures: The Case of Lumbar Spinal Fusion Surgery, a Literature Review and Pilot Series.

Science.gov (United States)

Liu, Jesse J; Raskin, Jeffrey S; Hardaway, Fran; Holste, Katherine; Brown, Sarah; Raslan, Ahmed M

2018-03-14

Delivery of higher value healthcare is an ultimate government and public goal. Improving efficiency by standardization of surgical steps can improve patient outcomes, reduce costs, and lead to higher value healthcare. Lean principles and methodology have improved timeliness in perioperative medicine; however, process mapping of surgery itself has not been performed. To apply Plan/Do/Study/Act (PDSA) cycles methodology to lumbar posterior instrumented fusion (PIF) using lean principles to create a standard work flow, identify waste, remove intraoperative variability, and examine feasibility among pilot cases. Process maps for 5 PIF procedures were created by a PDSA cycle from 1 faculty neurosurgeon at 1 institution. Plan, modularize PIF into basic components; Do, map and time components; Study, analyze results; and Act, identify waste. Waste inventories, spaghetti diagrams, and chartings of time spent per step were created. Procedural steps were broadly defined in order to compare steps despite the variability in PIF and were analyzed with box and whisker plots to evaluate variability. Temporal variabilities in duration of decompression vs closure and hardware vs closure were significantly different (P = .003). Variability in procedural step duration was smallest for closure and largest for exposure. Wastes including waiting and instrument defects accounted for 15% and 66% of all waste, respectively. This pilot series demonstrates that lean principles can standardize surgical workflows and identify waste. Though time and labor intensive, lean principles and PDSA methodology can be applied to operative steps, not just the perioperative period.

Chemical interactions between as-received and pre-oxidized Zircaloy-4 and stainless steel at high temperatures

International Nuclear Information System (INIS)

Hofmann, P.

1994-05-01

The chemical reaction behavior between Zircaloy-4 and 1.4919 (AISI 316) stainless steel, which are used in absorber assemblies of Pressurized Water Reactors (PWR) and Boiling Water Reactors (BWR), has been studied in the temperature range 1000 - 1400 C. Zircaloy was used in the as-received, pre-oxidized and oxygen-containing condition. The maximum temperature was limited by the fast and complete liquefaction of the reaction couple as a result of eutectic chemical interactions. Liquefaction of the components occurs below their melting point. The effect of oxygen dissolved in Zircaloy plays an important role in the interaction; oxide layers on the Zircaloy surface delay the chemical interactions with stainless steel but cannot prevent them. Oxygen dissolved in Zircaloy reduces the reaction rates and shift the liquefaction temperature to slightly higher levels. The interaction experiments at the examined temperatures with or without pre-oxidized Zircaloy can be described by parabolic rate laws. The Arrhenius equations for the various conditions of interactions are given. (orig.) [de

Apoptotic role of TGF-β mediated by Smad4 mitochondria translocation and cytochrome c oxidase subunit II interaction.

Science.gov (United States)

Pang, Lijuan; Qiu, Tao; Cao, Xu; Wan, Mei

2011-07-01

Smad4, originally isolated from the human chromosome 18q21, is a key factor in transducing the signals of the TGF-β superfamily of growth hormones and plays a pivotal role in mediating antimitogenic and proapoptotic effects of TGF-β, but the mechanisms by which Smad4 induces apoptosis are elusive. Here we report that Smad4 directly translocates to the mitochondria of apoptotic cells. Smad4 gene silencing by siRNA inhibits TGF-β-induced apoptosis in Hep3B cells and UV-induced apoptosis in PANC-1 cells. Cell fractionation assays demonstrated that a fraction of Smad4 translocates to mitochondria after long time TGF-β treatment or UV exposure, during which the cells were under apoptosis. Smad4 mitochondria translocation during apoptosis was also confirmed by fluorescence observation of Smad4 colocalization with MitoTracker Red. We searched for mitochondria proteins that have physical interactions with Smad4 using yeast two-hybrid screening approach. DNA sequence analysis identified 34 positive clones, five of which encoded subunits in mitochondria complex IV, i.e., one clone encoded cytochrome c oxidase COXII, three clones encoded COXIII and one clone encoded COXVb. Strong interaction between Smad4 with COXII, an important apoptosis regulator, was verified in yeast by β-gal activity assays and in mammalian cells by immunoprecipitation assays. Further, mitochondrial portion of cells was isolated and the interaction between COXII and Smad4 in mitochondria upon TGF-β treatment or UV exposure was confirmed. Importantly, targeting Smad4 to mitochondria using import leader fusions enhanced TGF-β-induced apoptosis. Collectively, the results suggest that Smad4 promote apoptosis of the cells through its mitochondrial translocation and association with mitochondria protein COXII. Copyright © 2011 Elsevier Inc. All rights reserved.

A calix[4]arene derivative and its selective interaction with drugs (clofibric acid, diclofenac and aspirin).

Science.gov (United States)

Danil de Namor, Angela F; Al Nuaim, Maan; Villanueva Salas, Jose A; Bryant, Sophie; Howlin, Brendan

2017-03-30

The synthesis and characterisation of a partially substituted calix[4]arene, namely, 5,11,17,23-tetra-tert-butyl,25,27-bis[aminoethoxy] 26,28-dihydroxycalix[4]arene are reported. Its interaction with commonly used pharmaceuticals (clofibric acid, diclofenac and aspirin) was investigated by spectroscopic ( 1 H NMR and UV), electrochemical (conductance measurements) and thermal (titration calorimetry) techniques. It is concluded on the basis of the experimental work and molecular simulation studies that the receptor interacts selectively with these drugs. Preliminary studies on the selective extraction of these pharmaceuticals from water by the calix receptor are reported and the potential for a carrier mediated sensor based on this ligand for 'on site' monitoring of pharmaceuticals is discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

High-temperature interaction in the ZrSiO4-TiO2 system

International Nuclear Information System (INIS)

Matveeva, F.A.; Melekhova, T.F.; Samsonova, T.I.

1976-01-01

The solid phase interaction in the ZrSiO 4 - TiO 2 system in the region of lower concentrations of TiO 2 (between 0-30%) when heating in the range 1400-1600 0 C is investigated. The different mechanism of the interaction of zircon and titanium dioxide with a content of titanium dioxide of 10% and higher is shown. In compounds with a TiO 2 content to 10%, a solid solution of titanium dioxide and zircon arises, with a limiting value of TiO 2 dissolving in zircon of 1% at 1400 0 C and 2% at 1500-1600 0 C. The partial decomposition of zircon giving crystobalite and the solid solution of separated zirconium dioxide with rutile occurs when the content of titanium dioxide is higher than 10%

3d-4f magnetic interaction with density functional theory plus u approach: local Coulomb correlation and exchange pathways.

Science.gov (United States)

Zhang, Yachao; Yang, Yang; Jiang, Hong

2013-12-12

The 3d-4f exchange interaction plays an important role in many lanthanide based molecular magnetic materials such as single-molecule magnets and magnetic refrigerants. In this work, we study the 3d-4f magnetic exchange interactions in a series of Cu(II)-Gd(III) (3d(9)-4f(7)) dinuclear complexes based on the numerical atomic basis-norm-conserving pseudopotential method and density functional theory plus the Hubbard U correction approach (DFT+U). We obtain improved description of the 4f electrons by including the semicore 5s5p states in the valence part of the Gd-pseudopotential. The Hubbard U correction is employed to treat the strongly correlated Cu-3d and Gd-4f electrons, which significantly improve the agreement of the predicted exchange constants, J, with experiment, indicating the importance of accurate description of the local Coulomb correlation. The high efficiency of the DFT+U approach enables us to perform calculations with molecular crystals, which in general improve the agreement between theory and experiment, achieving a mean absolute error smaller than 2 cm(-1). In addition, through analyzing the physical effects of U, we identify two magnetic exchange pathways. One is ferromagnetic and involves an interaction between the Cu-3d, O-2p (bridge ligand), and the majority-spin Gd-5d orbitals. The other one is antiferromagnetic and involves Cu-3d, O-2p, and the empty minority-spin Gd-4f orbitals, which is suppressed by the planar Cu-O-O-Gd structure. This study demonstrates the accuracy of the DFT+U method for evaluating the 3d-4f exchange interactions, provides a better understanding of the exchange mechanism in the Cu(II)-Gd(III) complexes, and paves the way for exploiting the magnetic properties of the 3d-4f compounds containing lanthanides other than Gd.

Utilidad de la sonografía transcraneal en el parkinsonismo farmacológico: ¿puede predecir la respuesta a la retirada del fármaco parkinsonizante?

OpenAIRE

Alonso Cánovas, Araceli

2015-01-01

Introducción y objetivos: La hiperecogenicidad de la sustancia negra (SN) detectada por sonografía transcraneal (STC) es un biomarcador fiable para el diagnóstico de Enfermedad de Parkinson (EP), fácil de obtener de forma económica y no invasiva por neurosonólogos expertos. El parkinsonismo inducido por fármacos (PIF) es la segunda causa más frecuente de parkinsonismo: su diagnóstico es complejo porque el 15% de los casos de posible PIF son una EP desenmascarada. El SPECT-DaTSCAN es capaz de ...

Plasma membrane calcium ATPase 4b inhibits nitric oxide generation through calcium-induced dynamic interaction with neuronal nitric oxide synthase.

Science.gov (United States)

Duan, Wenjuan; Zhou, Juefei; Li, Wei; Zhou, Teng; Chen, Qianqian; Yang, Fuyu; Wei, Taotao

2013-04-01

The activation and deactivation of Ca(2+)- and calmodulindependent neuronal nitric oxide synthase (nNOS) in the central nervous system must be tightly controlled to prevent excessive nitric oxide (NO) generation. Considering plasma membrane calcium ATPase (PMCA) is a key deactivator of nNOS, the present investigation aims to determine the key events involved in nNOS deactivation of by PMCA in living cells to maintain its cellular context. Using time-resolved Förster resonance energy transfer (FRET), we determined the occurrence of Ca(2+)-induced protein-protein interactions between plasma membrane calcium ATPase 4b (PMCA4b) and nNOS in living cells. PMCA activation significantly decreased the intracellular Ca(2+) concentrations ([Ca(2+)]i), which deactivates nNOS and slowdowns NO synthesis. Under the basal [Ca(2+)]i caused by PMCA activation, no protein-protein interactions were observed between PMCA4b and nNOS. Furthermore, both the PDZ domain of nNOS and the PDZ-binding motif of PMCA4b were essential for the protein-protein interaction. The involvement of lipid raft microdomains on the activity of PMCA4b and nNOS was also investigated. Unlike other PMCA isoforms, PMCA4 was relatively more concentrated in the raft fractions. Disruption of lipid rafts altered the intracellular localization of PMCA4b and affected the interaction between PMCA4b and nNOS, which suggest that the unique lipid raft distribution of PMCA4 may be responsible for its regulation of nNOS activity. In summary, lipid rafts may act as platforms for the PMCA4b regulation of nNOS activity and the transient tethering of nNOS to PMCA4b is responsible for rapid nNOS deactivation.

Interaction between NANOS2 and the CCR4-NOT deadenylation complex is essential for male germ cell development in mouse.

Directory of Open Access Journals (Sweden)

Atsushi Suzuki

Full Text Available Nanos is one of the evolutionarily conserved proteins implicated in germ cell development and we have previously shown that it interacts with the CCR4-NOT deadenylation complex leading to the suppression of specific RNAs. However, the molecular mechanism and physiological significance of this interaction have remained elusive. In our present study, we identify CNOT1, a component of the CCR4-NOT deadenylation complex, as a direct factor mediating the interaction with NANOS2. We find that the first 10 amino acids (AAs of NANOS2 are required for this binding. We further observe that a NANOS2 mutant lacking these first 10 AAs (NANOS2-ΔN10 fails to rescue defects in the Nanos2-null mouse. Our current data thus indicate that the interaction with the CCR4-NOT deadenylation complex is essential for NANOS2 function. In addition, we further demonstrate that NANOS2-ΔN10 can associate with specific mRNAs as well as wild-type NANOS2, suggesting the existence of other NANOS2-associated factor(s that determine the specificity of RNA-binding independently of the CCR4-NOT deadenylation complex.

Electronic Structure and Magnetic Interactions in the Radical Salt [BEDT-TTF]2[CuCl4].

Science.gov (United States)

Calzado, Carmen J; Rodríguez-García, Bárbara; Galán Mascarós, José Ramón; Hernández, Norge Cruz

2018-06-07

The magnetic behavior and electric properties of the hybrid radical salt [BEDT-TTF] 2 [CuCl 4 ] have been revisited through extended experimental analyses and DDCI and periodic DFT plane waves calculations. Single crystal X-ray diffraction data have been collected at different temperatures, discovering a phase transition occurring in the 250-300 K range. The calculations indicate the presence of intradimer, interdimer, and organic-inorganic π-d interactions in the crystal, a magnetic pattern much more complex than the Bleaney-Bowers model initially assigned to this material. Although this simple model was good enough to reproduce the magnetic susceptibility data, our calculations demonstrate that the actual magnetic structure is significantly more intricate, with alternating antiferromagnetic 1D chains of the organic BEDT-TTF + radical, connected through weak antiferromagnetic interactions with the CuCl 4 2- ions. Combination of experiment and theory allowed us to unambiguously determine and quantify the leading magnetic interactions in the system. The density-of-states curves confirm the semiconductor nature of the system and the dominant organic contribution of the valence and conduction band edges. This general and combined approach appears to be fundamental in order to properly understand the magnetic structure of these complex materials, where experimental data can actually be fitted from a variety of models and parameters.

Alteration of RNA splicing by small molecule inhibitors of the interaction between NHP2L1 and U4

Science.gov (United States)

Diouf, Barthelemy; Lin, Wenwei; Goktug, Asli; Grace, Christy R. R.; Waddell, Michael Brett; Bao, Ju; Shao, Youming; Heath, Richard J.; Zheng, Jie J.; Shelat, Anang A.; Relling, Mary V.; Chen, Taosheng; Evans, William E.

2018-01-01

Splicing is an important eukaryotic mechanism for expanding the transcriptome and proteome, influencing a number of biological processes. Understanding its regulation and identifying small molecules that modulate this process remains a challenge. We developed an assay based on time-resolved FRET (TR-FRET) to detect the interaction between the protein NHP2L1 and U4 RNA, which are two key components of the spliceosome. We used this assay to identify small molecules that interfere with this interaction in a high-throughput screening (HTS) campaign. Topotecan and other camptothecin derivatives were among the top hits. We confirmed that topotecan disrupts the interaction between NHP2L1 and U4 by binding to U4 and inhibits RNA splicing. Our data reveal new functions of known drugs which could facilitate the development of therapeutic strategies to modify splicing and alter gene function. PMID:28985478

Radiometric Normalization of Temporal Images Combining Automatic Detection of Pseudo-Invariant Features from the Distance and Similarity Spectral Measures, Density Scatterplot Analysis, and Robust Regression

Directory of Open Access Journals (Sweden)

Ana Paula Ferreira de Carvalho

2013-05-01

Full Text Available Radiometric precision is difficult to maintain in orbital images due to several factors (atmospheric conditions, Earth-sun distance, detector calibration, illumination, and viewing angles. These unwanted effects must be removed for radiometric consistency among temporal images, leaving only land-leaving radiances, for optimum change detection. A variety of relative radiometric correction techniques were developed for the correction or rectification of images, of the same area, through use of reference targets whose reflectance do not change significantly with time, i.e., pseudo-invariant features (PIFs. This paper proposes a new technique for radiometric normalization, which uses three sequential methods for an accurate PIFs selection: spectral measures of temporal data (spectral distance and similarity, density scatter plot analysis (ridge method, and robust regression. The spectral measures used are the spectral angle (Spectral Angle Mapper, SAM, spectral correlation (Spectral Correlation Mapper, SCM, and Euclidean distance. The spectral measures between the spectra at times t1 and t2 and are calculated for each pixel. After classification using threshold values, it is possible to define points with the same spectral behavior, including PIFs. The distance and similarity measures are complementary and can be calculated together. The ridge method uses a density plot generated from images acquired on different dates for the selection of PIFs. In a density plot, the invariant pixels, together, form a high-density ridge, while variant pixels (clouds and land cover changes are spread, having low density, facilitating its exclusion. Finally, the selected PIFs are subjected to a robust regression (M-estimate between pairs of temporal bands for the detection and elimination of outliers, and to obtain the optimal linear equation for a given set of target points. The robust regression is insensitive to outliers, i.e., observation that appears to deviate

Changes in regional cerebral blood flow in nondominant hemisphere during speech task in aphasics. A PET activation study

Energy Technology Data Exchange (ETDEWEB)

Ohyama, Masashi; Kitamura, Shin; Mishina, Masahiro; Terashi, Akiro [Nippon Medical School, Tokyo (Japan); Senda, Michio; Ishii, Kenji

1995-08-01

To investigate the patients with language disorder and to detect the activated areas in language processing, we measured the changes in the regional cerebral blood flow (CBF) during speech task (`counting` task) using O-15 water PET activation technique in six normal subjects (age 58.3 {+-}8.1, mean{+-}SD), ten fluent aphasics (age 60.3{+-}12.5) and six nonfluent aphasics (age 50.5{+-}8.3). In `counting` task, the subjects were instructed to count the number aloud from 1 to 10 and repeat the sequence over and over in the native language (Japanese) at the rate of one number per 2.5 sec. The data were analyzed with stereotactic intersubject averaging analysis for the normal subjects. Apart from it, the regions of interest (ROI) analysis (a circular ROI of 12 mm diameter) was performed in the language-related area for each subject. In the normal subjects, the language-related areas: posteroinferofrontal areas (PIF), posterosuperotemporal area (PST), and Rolandic areas (related to the mouth and lips) were significantly activated bilaterally in the `counting` task. PIF were activated with a dominance in the left side. In the resting state, rCBF in the left PIF and left PST was reduced in both fluent and nonfluent aphasics. In nonfluent aphasics, the magnitude of activation in the right PIF by `counting` task was significantly greater than normal subjects and patients with fluent aphasia (ANOVA). It suggests the importance of the right PIF in the simple language processing in the nonfluent aphasia. In the sixteen aphasic patients, the increase in rCBF in the right PST during the `counting` task was negatively correlated with the score of comprehension (WAB) in the Spearman ranked correlation (p<0.05). It suggests that, while the activity of the right PST is minimal for the `counting` in normal subjects, it plays an important and compensatory role in aphasic patients. (author).

Ventolin Diskus and Inspyril Turbuhaler: an in vitro comparison.

Science.gov (United States)

Broeders, M E A C; Molema, J; Burnell, P K P; Folgering, H T M

2005-01-01

Dose delivery (total emitted dose, or TED) from dry powder inhalers (DPIs), pulmonary deposition, and the biological effects depend on drug formulation and device and patient characteristics. The aim of this study was to measure, in vitro, the relationship between parameters of inhalation profiles recorded from patients, the TED and fine particle mass (FPM) of Diskus and Turbuhaler inhalers. Inhalation profiles (IPs) of 25 patients, a representative sample of a wide range of 1500 IPs generated by 10 stable asthmatics, 3 x 16 (mild/moderate/severe) COPD patients and 15 hospitalized patients with an exacerbation asthma or COPD, were selected for each device. These 25 IPs were input IPs for the Electronic Lung (a computerdriven inhalation simulator) to determine particle size distribution from Ventolin Diskus and Inspyril Turbuhaler. The TED and FPM of Diskus and FPM of Turbuhaler were affected by the peak inspiratory flow (PIF) and not by slope of the pressure-time curve, inhaled volume and inhalation time. This flow-dependency was more marked at lower flows (PIF TED and FPM of Diskus were significantly higher as compared to those of the Turbuhaler [mean (SD) TED(_diskus) (%label claim) 83.5 (13.9) vs. TED(_turbuhaler) (72.5 (11.1) (p = 0.004), FPM(_diskus) (%label claim) 36.8 (9.8) vs FPM(_turbuhaler) (28.7 (7.7) (p TED and FPM of Diskus and FPM of Turbuhaler were affected by PIF, the flow-dependency being greater at PIF values below 40 L/min. Lower PIFs occurred more often when using Turbuhaler than Diskus, since Turbuhaler have a higher resistivity, requires substantially higher pressure in order to generate the same flow as Diskus. TED, dose consistency and the FPM were higher for Diskus as compared to Turbuhaler. The flow dependency of TED and FPM was substantially influenced by inhalation profiles when not only profiles of the usual outpatient population were included but also the real outliers from exacerbated patients.

Changes in regional cerebral blood flow in nondominant hemisphere during speech task in aphasics. A PET activation study

International Nuclear Information System (INIS)

Ohyama, Masashi; Kitamura, Shin; Mishina, Masahiro; Terashi, Akiro; Senda, Michio; Ishii, Kenji.

1995-01-01

To investigate the patients with language disorder and to detect the activated areas in language processing, we measured the changes in the regional cerebral blood flow (CBF) during speech task ('counting' task) using O-15 water PET activation technique in six normal subjects (age 58.3 ±8.1, mean±SD), ten fluent aphasics (age 60.3±12.5) and six nonfluent aphasics (age 50.5±8.3). In 'counting' task, the subjects were instructed to count the number aloud from 1 to 10 and repeat the sequence over and over in the native language (Japanese) at the rate of one number per 2.5 sec. The data were analyzed with stereotactic intersubject averaging analysis for the normal subjects. Apart from it, the regions of interest (ROI) analysis (a circular ROI of 12 mm diameter) was performed in the language-related area for each subject. In the normal subjects, the language-related areas: posteroinferofrontal areas (PIF), posterosuperotemporal area (PST), and Rolandic areas (related to the mouth and lips) were significantly activated bilaterally in the 'counting' task. PIF were activated with a dominance in the left side. In the resting state, rCBF in the left PIF and left PST was reduced in both fluent and nonfluent aphasics. In nonfluent aphasics, the magnitude of activation in the right PIF by 'counting' task was significantly greater than normal subjects and patients with fluent aphasia (ANOVA). It suggests the importance of the right PIF in the simple language processing in the nonfluent aphasia. In the sixteen aphasic patients, the increase in rCBF in the right PST during the 'counting' task was negatively correlated with the score of comprehension (WAB) in the Spearman ranked correlation (p<0.05). It suggests that, while the activity of the right PST is minimal for the 'counting' in normal subjects, it plays an important and compensatory role in aphasic patients. (author)

Evolutionary recycling of light signaling components in fleshy fruits: new insights on the role of pigments to monitor ripening

Directory of Open Access Journals (Sweden)

Briardo eLlorente

2016-03-01

Full Text Available Besides an essential source of energy, light provides environmental information to plants. Photosensory pathways are thought to have occurred early in plant evolution, probably at the time of the Archaeplastida ancestor, or perhaps even earlier. Manipulation of individual components of light perception and signaling networks in tomato (Solanum lycopersicum affects the metabolism of ripening fruit at several levels. Most strikingly, recent experiments have shown that some of the molecular mechanisms originally devoted to sense and respond to environmental light cues have been re-adapted during evolution to provide plants with useful information on fruit ripening progression. In particular, the presence of chlorophylls in green fruit can strongly influence the spectral composition of the light filtered through the fruit pericarp. The concomitant changes in light quality can be perceived and transduced by phytochromes and phytochrome-interacting factors, respectively, to regulate gene expression and in turn modulate the production of carotenoids, a family of metabolites that are relevant for the final pigmentation of ripe fruits. We raise the hypothesis that the evolutionary recycling of light-signaling components to finely adjust pigmentation to the actual ripening stage of the fruit may have represented a selective advantage for primeval fleshy-fruited plants even before the extinction of dinosaurs.

Genome-wide binding site analysis of FAR-RED ELONGATED HYPOCOTYL3 reveals its novel function in Arabidopsis development.

Science.gov (United States)

Ouyang, Xinhao; Li, Jigang; Li, Gang; Li, Bosheng; Chen, Beibei; Shen, Huaishun; Huang, Xi; Mo, Xiaorong; Wan, Xiangyuan; Lin, Rongcheng; Li, Shigui; Wang, Haiyang; Deng, Xing Wang

2011-07-01

FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and its homolog FAR-RED IMPAIRED RESPONSE1 (FAR1), two transposase-derived transcription factors, are key components in phytochrome A signaling and the circadian clock. Here, we use chromatin immunoprecipitation-based sequencing (ChIP-seq) to identify 1559 and 1009 FHY3 direct target genes in darkness (D) and far-red (FR) light conditions, respectively, in the Arabidopsis thaliana genome. FHY3 preferentially binds to promoters through the FHY3/FAR1 binding motif (CACGCGC). Interestingly, FHY3 also binds to two motifs in the 178-bp Arabidopsis centromeric repeats. Comparison between the ChIP-seq and microarray data indicates that FHY3 quickly regulates the expression of 197 and 86 genes in D and FR, respectively. FHY3 also coregulates a number of common target genes with PHYTOCHROME INTERACTING FACTOR 3-LIKE5 and ELONGATED HYPOCOTYL5. Moreover, we uncover a role for FHY3 in controlling chloroplast development by directly activating the expression of ACCUMULATION AND REPLICATION OF CHLOROPLASTS5, whose product is a structural component of the latter stages of chloroplast division in Arabidopsis. Taken together, our data suggest that FHY3 regulates multiple facets of plant development, thus providing insights into its functions beyond light and circadian pathways.

A key centriole assembly interaction interface between human PLK4 and STIL appears to not be conserved in flies

Directory of Open Access Journals (Sweden)

Matthew A. Cottee

2017-03-01

Full Text Available A small number of proteins form a conserved pathway of centriole duplication. In humans and flies, the binding of PLK4/Sak to STIL/Ana2 initiates daughter centriole assembly. In humans, this interaction is mediated by an interaction between the Polo-Box-3 (PB3 domain of PLK4 and the coiled-coil domain of STIL (HsCCD. We showed previously that the Drosophila Ana2 coiled-coil domain (DmCCD is essential for centriole assembly, but it forms a tight parallel tetramer in vitro that likely precludes an interaction with PB3. Here, we show that the isolated HsCCD and HsPB3 domains form a mixture of homo-multimers in vitro, but these readily dissociate when mixed to form the previously described 1:1 HsCCD:HsPB3 complex. In contrast, although Drosophila PB3 (DmPB3 adopts a canonical polo-box fold, it does not detectably interact with DmCCD in vitro. Thus, surprisingly, a key centriole assembly interaction interface appears to differ between humans and flies.

'cold' events in 12C–AgBr interactions at 4.5 A GeV

Indian Academy of Sciences (India)

from the same data of 12C–AgBr interactions at 4.5 A GeV by Takagi moments method, which are different from those obtained in the present work. The quan- titative disagreement in the values of Dq's is due to the different approaches for determination of the generalized dimension (Dq). It is extremely interesting to observe ...

Binding of Substrates to the Central Pore of the Vps4 ATPase Is Autoinhibited by the Microtubule Interacting and Trafficking (MIT) Domain and Activated by MIT Interacting Motifs (MIMs).

Science.gov (United States)

Han, Han; Monroe, Nicole; Votteler, Jörg; Shakya, Binita; Sundquist, Wesley I; Hill, Christopher P

2015-05-22

The endosomal sorting complexes required for transport (ESCRT) pathway drives reverse topology membrane fission events within multiple cellular pathways, including cytokinesis, multivesicular body biogenesis, repair of the plasma membrane, nuclear membrane vesicle formation, and HIV budding. The AAA ATPase Vps4 is recruited to membrane necks shortly before fission, where it catalyzes disassembly of the ESCRT-III lattice. The N-terminal Vps4 microtubule-interacting and trafficking (MIT) domains initially bind the C-terminal MIT-interacting motifs (MIMs) of ESCRT-III subunits, but it is unclear how the enzyme then remodels these substrates in response to ATP hydrolysis. Here, we report quantitative binding studies that demonstrate that residues from helix 5 of the Vps2p subunit of ESCRT-III bind to the central pore of an asymmetric Vps4p hexamer in a manner that is dependent upon the presence of flexible nucleotide analogs that can mimic multiple states in the ATP hydrolysis cycle. We also find that substrate engagement is autoinhibited by the Vps4p MIT domain and that this inhibition is relieved by binding of either Type 1 or Type 2 MIM elements, which bind the Vps4p MIT domain through different interfaces. These observations support the model that Vps4 substrates are initially recruited by an MIM-MIT interaction that activates the Vps4 central pore to engage substrates and generate force, thereby triggering ESCRT-III disassembly. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Binding of Substrates to the Central Pore of the Vps4 ATPase Is Autoinhibited by the Microtubule Interacting and Trafficking (MIT) Domain and Activated by MIT Interacting Motifs (MIMs)*

Science.gov (United States)

Han, Han; Monroe, Nicole; Votteler, Jörg; Shakya, Binita; Sundquist, Wesley I.; Hill, Christopher P.

2015-01-01

The endosomal sorting complexes required for transport (ESCRT) pathway drives reverse topology membrane fission events within multiple cellular pathways, including cytokinesis, multivesicular body biogenesis, repair of the plasma membrane, nuclear membrane vesicle formation, and HIV budding. The AAA ATPase Vps4 is recruited to membrane necks shortly before fission, where it catalyzes disassembly of the ESCRT-III lattice. The N-terminal Vps4 microtubule-interacting and trafficking (MIT) domains initially bind the C-terminal MIT-interacting motifs (MIMs) of ESCRT-III subunits, but it is unclear how the enzyme then remodels these substrates in response to ATP hydrolysis. Here, we report quantitative binding studies that demonstrate that residues from helix 5 of the Vps2p subunit of ESCRT-III bind to the central pore of an asymmetric Vps4p hexamer in a manner that is dependent upon the presence of flexible nucleotide analogs that can mimic multiple states in the ATP hydrolysis cycle. We also find that substrate engagement is autoinhibited by the Vps4p MIT domain and that this inhibition is relieved by binding of either Type 1 or Type 2 MIM elements, which bind the Vps4p MIT domain through different interfaces. These observations support the model that Vps4 substrates are initially recruited by an MIM-MIT interaction that activates the Vps4 central pore to engage substrates and generate force, thereby triggering ESCRT-III disassembly. PMID:25833946

Interaction in vitro between the proteinase of Tomato ringspot virus (genus Nepovirus) and the eukaryotic translation initiation factor iso4E from Arabidopsis thaliana.

Science.gov (United States)

Léonard, Simon; Chisholm, Joan; Laliberté, Jean-François; Sanfaçon, Hélène

2002-08-01

Eukaryotic initiation factor eIF(iso)4E binds to the cap structure of mRNAs leading to assembly of the translation complex. This factor also interacts with the potyvirus VPg and this interaction has been correlated with virus infectivity. In this study, we show an interaction between eIF(iso)4E and the proteinase (Pro) of a nepovirus (Tomato ringspot virus; ToRSV) in vitro. The ToRSV VPg did not interact with eIF(iso)4E although its presence on the VPg-Pro precursor increased the binding affinity of Pro for the initiation factor. A major determinant of the interaction was mapped to the first 93 residues of Pro. Formation of the complex was inhibited by addition of m(7)GTP (a cap analogue), suggesting that Pro-containing molecules compete with cellular mRNAs for eIF(iso)4E binding. The possible implications of this interaction for translation and/or replication of the virus genome are discussed.

α-Taxilin interacts with sorting nexin 4 and participates in the recycling pathway of transferrin receptor.

Directory of Open Access Journals (Sweden)

Hiroshi Sakane

Full Text Available Membrane traffic plays a crucial role in delivering proteins and lipids to their intracellular destinations. We previously identified α-taxilin as a binding partner of the syntaxin family, which is involved in intracellular vesicle traffic. α-Taxilin is overexpressed in tumor tissues and interacts with polymerized tubulin, but the precise function of α-taxilin remains unclear. Receptor proteins on the plasma membrane are internalized, delivered to early endosomes and then either sorted to the lysosome for degradation or recycled back to the plasma membrane. In this study, we found that knockdown of α-taxilin induced the lysosomal degradation of transferrin receptor (TfnR, a well-known receptor which is generally recycled back to the plasma membrane after internalization, and impeded the recycling of transferrin. α-Taxilin was immunoprecipitated with sorting nexin 4 (SNX4, which is involved in the recycling of TfnR. Furthermore, knockdown of α-taxilin decreased the number and length of SNX4-positive tubular structures. We report for the first time that α-taxilin interacts with SNX4 and plays a role in the recycling pathway of TfnR.

Association of Maternal Interaction with Emotional Regulation in 4 and 9 Month Infants During the Still Face Paradigm

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Lowe, Jean R.; MacLean, Peggy C.; Duncan, Andrea F.; Aragón, Crystal; Schrader, Ronald M.; Caprihan, Arvind; Phillips, John P.

2013-01-01

This study used the Still Face Paradigm to investigate the relationship of maternal interaction on infants’ emotion regulation responses. Seventy infant-mother dyads were seen at 4 months and 25 of these same dyads were re-evaluated at 9 months. Maternal interactions were coded for attention seeking and contingent responding. Emotional regulation was described by infant stress reaction and overall positive affect. Results indicated that at both 4 and 9 months mothers who used more contingent responding interactions had infants who showed more positive affect. In contrast, mothers who used more attention seeking play had infants who showed less positive affect after the Still Face Paradigm. Patterns of stress reaction were reversed, as mothers who used more attention seeking play had infants with less negative affect. Implications for intervention and emotional regulation patterns over time are discussed. PMID:22217393

Observation of Collective flow in interactions of 4.1(4.5) A GeV/c {sup 22}Ne({sup 28}Si) with Ag(Br)

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El-Naghy, A; Fakhraddin, S [Physics department, Faculty of Science, Cairo University, Giza (Egypt)

2000-11-15

The study of the transverse momentum analysis and the angle of flow analysis lead to the observation of the side ward flow of the nuclear matter in the interactions of 4.1(4.5) {sup 22}Ne({sup 28}Si) with Ag(Br). The distribution of the angle between the resultant vectors of the projectile and the target fragments showed a strong correlation between them in the azimuthal plane.

Annexin A4 fucosylation enhances its interaction with the NF-kB p50 and promotes tumor progression of ovarian clear cell carcinoma.

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Wang, Huimin; Deng, Lu; Cai, Mingbo; Zhuang, Huiyu; Zhu, Liancheng; Hao, Yingying; Gao, Jian; Liu, Juanjuan; Li, Xiao; Lin, Bei

2017-12-08

To study the structural relationship between annexin A4 and the Lewis y antigen and compare their expression and significance in ovarian clear cell carcinoma, and to explore how annexin A4 fucose glycosylation effects the interaction between annexin A4 and NF-kB p50, and how it promotes tumour progression of ovarian clear cell carcinoma. Structural relationships between annexin A4 and Lewis y antigen were detected using immunoprecipitation. Annexin A4 and Lewis y antigen expression in various subtypes of ovarian cancer tissues was detected by immunohistochemistry, and the relation between their expression was examined. Any interactions between annexin A4 and NF-kB p50 in ovarian clear cell carcinoma were detected by co-immunoprecipitation. Then looked for changes in expression of Lewis y antigen, annexin A4, NF-kB p50 and a number of downstream related molecules before and after transfection annexin A4 or FUT1, and also analyzed changes in biological processes. Lewis y antigen is a part of annexin A4 structure. The expression rate of both annexin A4 and Lewis y antigen was significantly higher in ovarian clear cell carcinoma than in other subtypes of epithelial ovarian cancer, and are associated with the clinical stages, chemotherapy resistance and poor prognostic. The interaction between annexin A4 and NF-kB p50 promoted cell proliferation, adhesion, invasion, metastasis ability and autophagy, and inhibits apoptosis, Lewis y enhanced this interaction. Annexin A4 contains Lewis y structure, Lewis y antigen modification of annexin A4 enhances its interaction with NF-kB p50, which promotes ovarian clear cell carcinoma malignancy progression.

Respiratory Syncytial Virus Fusion Protein-Induced Toll-Like Receptor 4 (TLR4) Signaling Is Inhibited by the TLR4 Antagonists Rhodobacter sphaeroides Lipopolysaccharide and Eritoran (E5564) and Requires Direct Interaction with MD-2

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Rallabhandi, Prasad; Phillips, Rachel L.; Boukhvalova, Marina S.; Pletneva, Lioubov M.; Shirey, Kari Ann; Gioannini, Theresa L.; Weiss, Jerrold P.; Chow, Jesse C.; Hawkins, Lynn D.; Vogel, Stefanie N.; Blanco, Jorge C. G.

2012-01-01

ABSTRACT Respiratory syncytial virus (RSV) is a leading cause of infant mortality worldwide. Toll-like receptor 4 (TLR4), a signaling receptor for structurally diverse microbe-associated molecular patterns, is activated by the RSV fusion (F) protein and by bacterial lipopolysaccharide (LPS) in a CD14-dependent manner. TLR4 signaling by LPS also requires the presence of an additional protein, MD-2. Thus, it is possible that F protein-mediated TLR4 activation relies on MD-2 as well, although this hypothesis has not been formally tested. LPS-free RSV F protein was found to activate NF-κB in HEK293T transfectants that express wild-type (WT) TLR4 and CD14, but only when MD-2 was coexpressed. These findings were confirmed by measuring F-protein-induced interleukin 1β (IL-1β) mRNA in WT versus MD-2−/− macrophages, where MD-2−/− macrophages failed to show IL-1β expression upon F-protein treatment, in contrast to the WT. Both Rhodobacter sphaeroides LPS and synthetic E5564 (eritoran), LPS antagonists that inhibit TLR4 signaling by binding a hydrophobic pocket in MD-2, significantly reduced RSV F-protein-mediated TLR4 activity in HEK293T-TLR4–CD14–MD-2 transfectants in a dose-dependent manner, while TLR4-independent NF-κB activation by tumor necrosis factor alpha (TNF-α) was unaffected. In vitro coimmunoprecipitation studies confirmed a physical interaction between native RSV F protein and MD-2. Further, we demonstrated that the N-terminal domain of the F1 segment of RSV F protein interacts with MD-2. These data provide new insights into the importance of MD-2 in RSV F-protein-mediated TLR4 activation. Thus, targeting the interaction between MD-2 and RSV F protein may potentially lead to novel therapeutic approaches to help control RSV-induced inflammation and pathology. PMID:22872782

Influence of O{sub 2} exposure on the interaction between CH{sub 4} and amorphous AlYB{sub 14}

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Hunold, Oliver, E-mail: hunold@mch.rwth-aachen.de [Materials Chemistry, RWTH Aachen University, Kopernikusstr, 10, D-52074 Aachen (Germany); Wiesing, Martin; Arcos, Teresa de los [Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100, D-33098 Paderborn (Germany); Music, Denis [Materials Chemistry, RWTH Aachen University, Kopernikusstr, 10, D-52074 Aachen (Germany); Grundmeier, Guido [Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100, D-33098 Paderborn (Germany); Schneider, Jochen M. [Materials Chemistry, RWTH Aachen University, Kopernikusstr, 10, D-52074 Aachen (Germany)

2017-01-15

Highlights: • Influence of O{sub 2} exposure on the surface chemistry of a-AlYB{sub 14} on the interaction with CH{sub 4} and PE studied by ab initio and UHV-AFM. • Predicted stronger interaction is consistent with experimentally observed trends. • Upon O{sub 2} exposure surface bonding becomes more semiconducting causing a charge redistribution within the adsorbed CH{sub 4} molecule. • The data serve as proof of concept for exploring polymer − hard coating interactions in varying atmospheres. - Abstract: The influence of surface oxidation on the interaction between CH{sub 4} and amorphous AlYB{sub 14} (a-AlYB{sub 14}) has been studied theoretically by using density functional theory and experimentally by ultra-high vacuum atomic force microscopy (UHV-AFM). CH{sub 4} mimics the –CH{sub 3} termination and aliphatic subunits of a polymer chain. Low-energy ion scattering measurements of magnetron sputtered thin films suggest that the bonding at the surfaces of pristine a-AlYB{sub 14} and O{sub 2} exposed a-AlYB{sub 14} (O{sub 2}//a-AlYB{sub 14}) is metal-boron and metal-oxygen dominated, respectively. Based on the ab initio calculations the adsorption energies of CH{sub 4} on a-AlYB{sub 14} and O{sub 2}//a-AlYB{sub 14} decreases from −0.07 to −0.30 eV, respectively. This trend is consistent with experimental data obtained by colloidal probe UHV-AFM studies with a polyethylene sphere, where larger adhesion forces for the O{sub 2} exposed surface as compared to the pristine a-AlYB{sub 14} surface were measured. No charge transfer takes place between CH{sub 4} and the pristine as well as the O{sub 2} exposed a-AlYB{sub 14}. Oxygen chemisorption induces changes in surface bonding. States at the Fermi level are depleted upon oxidation, hence the surface bonding becomes more semiconducting causing a charge redistribution within the adsorbed CH{sub 4} molecule. Hence, these data serve as proof of concept for exploring the effect of O{sub 2} exposure on the

Functional Magnetic Stimulation of Inspiratory and Expiratory Muscles in Subjects With Tetraplegia.

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Zhang, Xiaoming; Plow, Ela; Ranganthan, Vinoth; Huang, Honglian; Schmitt, Melissa; Nemunaitis, Gregory; Kelly, Clay; Frost, Frederick; Lin, Vernon

2016-07-01

Respiratory complications are major causes of morbidity and mortality in persons with a spinal cord injury, partly because of respiratory muscle paralysis. Earlier investigation has demonstrated that functional magnetic stimulation (FMS) can be used as a noninvasive technology for activating expiratory muscles, thus producing useful expiratory functions (simulated cough) in subjects with spinal cord injury. To evaluate the effectiveness of FMS for conditioning inspiratory and expiratory muscles in persons with tetraplegia. A prospective before and after trial. FMS Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, OH. Six persons with tetraplegia. Each subject participated in a 6-week FMS protocol for conditioning the inspiratory and expiratory muscles. A magnetic stimulator was used with the center of a magnetic coil placed at the C7-T1 and T9-T10 spinous processes, respectively. Pulmonary function tests were performed before, during, and after the protocol. Respiratory variables included maximal inspiratory pressure (MIP), inspiratory reserve volume (IRV), peak inspiratory flow (PIF), maximal expiratory pressure (MEP), expiratory reserve volume (ERV), and peak expiratory flow (PEF). After 6 weeks of conditioning, the main outcome measurements (mean ± standard error) were as follows: MIP, 89.6 ± 7.3 cm H2O; IRV, 1.90 ± 0.34 L; PIF, 302.4 ± 36.3 L/min; MEP, 67.4 ± 11.1 cm H2O; ERV, 0.40 ± 0.06 L; and PEF, 372.4 ± 31.9 L/min. These values corresponded to 117%, 107%, 136%, 109%, 130%, and 124% of pre-FMS conditioning values, respectively. Significant improvements were observed in MIP (P = .022), PIF (P = .0001), and PEF (P = .0006), respectively. When FMS was discontinued for 4 weeks, these values showed decreases from their values at the end of the conditioning protocol, which suggests that continual FMS may be necessary to maintain improved respiratory functions. FMS conditioning of the inspiratory and expiratory muscles improved

Interaction between Y chromosome haplogroup O3* and 4-n-octylphenol exposure reduces the susceptibility to spermatogenic impairment in Han Chinese.

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Hu, Weiyue; Chen, Minjian; Ji, Juan; Qin, Yufeng; Zhang, Feng; Xu, Miaofei; Wu, Wei; Du, Guizhen; Wu, Di; Han, Xiumei; Jin, Li; Xia, Yankai; Lu, Chuncheng; Wang, Xinru

2017-10-01

Certain genetic background (mainly Y chromosome haplogroups, Y-hg) may modify the susceptibility of certain environmental exposure to some diseases. Compared with respective main effects of genetic background or environmental exposure, interactions between them reflect more realistic combined effects on the susceptibility to a disease. To identify the interactions on spermatogenic impairment, we performed Y chromosome haplotyping and measurement of 9 urinary phenols concentrations in 774 infertile males and 520 healthy controls in a Han Chinese population, and likelihood ratio tests were used to examine the interactions between Y-hgs and phenols. Originally, we observed that Y-hg C and Y-hg F * might modify the susceptibility to male infertility with urinary 4-n-octylphenol (4-n-OP) level (P inter = 0.005 and 0.019, respectively). Subsequently, based on our results, two panels were tested to identify the possible protective sub-branches of Y-hg F * to 4-n-OP exposure, and Y-hg O3 * was uncovered to interact with 4-n-OP (P inter = 0.019). In conclusion, while 4-n-OP shows an adverse effect on spermatogenesis, Y-hg O3 * makes individuals more adaptive to such an effect for maintaining basic reproductive capacity. Copyright © 2017 Elsevier Inc. All rights reserved.

Spectroscopic studies of 7, 8-dihydroxy-4-methylcoumarin and its interaction with bovine serum albumin

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Hussein, Belal H.M., E-mail: belalhussein102@yahoo.co [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

2011-05-15

The absorption and fluorescence spectra of 7, 8-dihydroxy-4-methylcoumarin (DHMC) in ethanol-water (1:9 v/v) solution at varying pH values were investigated . The interaction between DHMC and bovine serum albumin (BSA) was investigated by fluorescence, FT-IR, and circular dichroism (CD) spectroscopy. The Stern-Volmer quenching constant (K{sub SV}), the quenching rate constant of the bimolecular reaction (K{sub q}), the binding constant, and number of binding sites (n) of DHMC with BSA were evaluated. The results showed that DHMC quenches the fluorescence intensity of BSA through a static quenching process. Positive value of entropy change ({Delta}S) and negative value of enthalpy change ({Delta}H) of the BSA-DHMC interaction were obtained according to the van't Hoff equation. The interaction between DHMC and BSA was driven mainly by hydrophobic forces. The binding process was spontaneous and exothermic. The binding distance between the tryptophan residue in BSA and the DHMC was found to be about 2.6 nm based on the Foerster theory of non-radiation energy transfer. - Research highlights: {yields} 7,8-dihydroxy-4-methylcoumarin (DHMC) quenched the bovine serum albumin (BSA) fluorescence. {yields} The formation of the DHMC-BSA complex was spontaneous through a static quenching process. {yields} The polarity around the tryptophan residues decreased with the increase of DHMC concentration.

Interactions between 4-aminoquinoline and heme: Promising mechanism against Trypanosoma cruzi

Directory of Open Access Journals (Sweden)

Guilherme Curty Lechuga

2016-12-01

Full Text Available Chagas disease is a neglected tropical disease caused by the flagellated protozoan Trypanosoma cruzi. The current drugs used to treat this disease have limited efficacy and produce severe side effects. Quinolines, nitrogen heterocycle compounds that form complexes with heme, have a broad spectrum of antiprotozoal activity and are a promising class of new compounds for Chagas disease chemotherapy. In this study, we evaluated the activity of a series of 4-arylaminoquinoline-3-carbonitrile derivatives against all forms of Trypanosoma cruzi in vitro. Compound 1g showed promising activity against epimastigote forms when combined with hemin (IC50<1 μM, with better performance than benznidazole, the reference drug. This compound also inhibited the viability of trypomastigotes and intracellular amastigotes. The potency of 1g in combination with heme was enhanced against epimastigotes and trypomastigotes, suggesting a similar mechanism of action that occurs in Plasmodium spp. The addition of hemin to the culture medium increased trypanocidal activity of analog 1g without changing the cytotoxicity of the host cell, reaching an IC50 of 11.7 μM for trypomastigotes. The mechanism of action was demonstrated by the interaction of compound 1g with hemin in solution and prevention of heme peroxidation. Compound 1g and heme treatment induced alterations of the mitochondrion-kinetoplast complex in epimastigotes and trypomastigotes and also, accumulation of electron-dense deposits in amastigotes as visualized by transmission electron microscopy. The trypanocidal activity of 4-aminoquinolines and the elucidation of the mechanism involving interaction with heme is a neglected field of research, given the parasite's lack of heme biosynthetic pathway and the importance of this cofactor for parasite survival and growth. The results of this study can improve and guide rational drug development and combination treatment strategies.

Interactions between 4-aminoquinoline and heme: Promising mechanism against Trypanosoma cruzi.

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Lechuga, Guilherme Curty; Borges, Júlio Cesar; Calvet, Claudia Magalhães; de Araújo, Humberto Pinheiro; Zuma, Aline Araujo; do Nascimento, Samara Braga; Motta, Maria Cristina Machado; Bernardino, Alice Maria Rolim; Pereira, Mirian Claudia de Souza; Bourguignon, Saulo Cabral

2016-12-01

Chagas disease is a neglected tropical disease caused by the flagellated protozoan Trypanosoma cruzi. The current drugs used to treat this disease have limited efficacy and produce severe side effects. Quinolines, nitrogen heterocycle compounds that form complexes with heme, have a broad spectrum of antiprotozoal activity and are a promising class of new compounds for Chagas disease chemotherapy. In this study, we evaluated the activity of a series of 4-arylaminoquinoline-3-carbonitrile derivatives against all forms of Trypanosoma cruzi in vitro. Compound 1g showed promising activity against epimastigote forms when combined with hemin (IC50<1 μM), with better performance than benznidazole, the reference drug. This compound also inhibited the viability of trypomastigotes and intracellular amastigotes. The potency of 1g in combination with heme was enhanced against epimastigotes and trypomastigotes, suggesting a similar mechanism of action that occurs in Plasmodium spp. The addition of hemin to the culture medium increased trypanocidal activity of analog 1g without changing the cytotoxicity of the host cell, reaching an IC50 of 11.7 μM for trypomastigotes. The mechanism of action was demonstrated by the interaction of compound 1g with hemin in solution and prevention of heme peroxidation. Compound 1g and heme treatment induced alterations of the mitochondrion-kinetoplast complex in epimastigotes and trypomastigotes and also, accumulation of electron-dense deposits in amastigotes as visualized by transmission electron microscopy. The trypanocidal activity of 4-aminoquinolines and the elucidation of the mechanism involving interaction with heme is a neglected field of research, given the parasite's lack of heme biosynthetic pathway and the importance of this cofactor for parasite survival and growth. The results of this study can improve and guide rational drug development and combination treatment strategies. Copyright © 2016 The Authors. Published by Elsevier

Comparative Analyses of Tomato yellow leaf curl virus C4 Protein-Interacting Host Proteins in Healthy and Infected Tomato Tissues

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Namgyu Kim

2016-10-01

Full Text Available Tomato yellow leaf curl virus (TYLCV, a member of the genus Begomovirus, is one of the most important viruses of cultivated tomatoes worldwide, mainly causing yellowing and curling of leaves with stunting in plants. TYLCV causes severe problems in sub-tropical and tropical countries, as well as in Korea. However, the mechanism of TYLCV infection remains unclear, although the function of each viral component has been identified. TYLCV C4 codes for a small protein involved in various cellular functions, including symptom determination, gene silencing, viral movement, and induction of the plant defense response. In this study, through yeast-two hybrid screenings, we identified TYLCV C4-interacting host proteins from both healthy and symptom-exhibiting tomato tissues, to determine the role of TYLCV C4 proteins in the infection processes. Comparative analyses of 28 proteins from healthy tissues and 36 from infected tissues showing interactions with TYLCV C4 indicated that TYLCV C4 mainly interacts with host proteins involved in translation, ubiquitination, and plant defense, and most interacting proteins differed between the two tissues but belong to similar molecular functional categories. Four proteins—two ribosomal proteins, S-adenosyl-L-homocysteine hydrolase, and 14-3-3 family protein—were detected in both tissues. Furthermore, the identified proteins in symptom-exhibiting tissues showed greater involvement in plant defenses. Some are key regulators, such as receptor-like kinases and pathogenesis-related proteins, of plant defenses. Thus, TYLCV C4 may contribute to the suppression of host defense during TYLCV infection and be involved in ubiquitination for viral infection.

Glycine Betaine Recognition through Cation−π Interactions in Crystal Structures of Glycine Betaine Complexes with C-Ethyl-pyrogallol[4]arene and C-Ethyl-resorcin[4]arene as Receptors

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Ikuhide Fujisawa

2013-04-01

Full Text Available The glycine betaine (betaine, interacts with several types of proteins with diverse structures in vivo, and in the contact regions, the aromatic rings of protein residues are frequently found beside the trimethylammonium group of betaine, implying the importance of the cation−π interactions in recognition of this molecule. The crystal structures determined by X-ray crystallography of the complexes of betaine and C-ethyl-pyrogallol[4]arene (pyrogallol cyclic tetramer: PCT and betaine and C-ethyl-resorcin[4]arene (resorcinol cyclic tetramer: RCT mimic the conformations of betaine and protein complexes and show that the clathrate conformations are retained by the cation−π interactions. The difference of the conformation feature of betaine in the Protein Data Bank and in the Cambridge Structural Database was found by chance during the research and analyzed with the torsion angles.

Development and construction of a specific chamber for phototoxicity test

International Nuclear Information System (INIS)

Sufi, Bianca S.; Mathor, Monica B.; Esteves-Pedro, Natalia M.; Kaneko, Telma Mary

2013-01-01

Phototoxicity corresponds to the acute toxic response induced after skin exposure 'in vivo' and 'ex vivo' to certain chemicals and subsequent exposure to irradiation. Phototoxicity 'in vitro' assay is determined by viability of fibroblasts BALB/c 3T3 exposed to chemicals in the presence and absence of light. Substances identified as phototoxic are susceptible to 'in vivo' phototoxicity (OECD 432, 2004). A chamber was developed and constructed according to the guidelines OECD Toxicity Guide - 432 and ®ECVAM DB-ALM: INVITTOX N. 78. The chamber was built in stainless steel frame, with UVA lamps and dark area for negative control. The tests to qualify the chamber were performed with Sodium Lauryl Sulfate, recommended by the guides aforementioned, as negative control; and Bergamot oil (Givaudan-Roche), as positive control. Bergamot, Citrus bergamia, has, as major component, Bergapten responsible for its photosensitive activity. Both samples were diluted in Phosphate Buffered Saline with concentrations between 0.005 and 0.1 mg/mL, which were calculated by the dilution factor 1.47. These tests were performed over fibroblast BALB/c 3T3 culture and submitted to phototoxicity assay with MTS dye, under spectrophotometric reading, which allows determining the Photo Irritation Factor (PIF), what suggests that a substance with a PIF 2 and 5 provides phototoxicity. Sodium Lauryl Sulfate presented a PIF=1, being in accordance with the OECD. Bergamot oil has shown to be likely phototoxic with a PIF=2,475. These results provide that the chamber is qualified to be used to perform phototoxicity tests with assurance and security. (author)

Oxidative DNA damage causes mitochondrial genomic instability in Saccharomyces cerevisiae.

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Doudican, Nicole A; Song, Binwei; Shadel, Gerald S; Doetsch, Paul W

2005-06-01

Mitochondria contain their own genome, the integrity of which is required for normal cellular energy metabolism. Reactive oxygen species (ROS) produced by normal mitochondrial respiration can damage cellular macromolecules, including mitochondrial DNA (mtDNA), and have been implicated in degenerative diseases, cancer, and aging. We developed strategies to elevate mitochondrial oxidative stress by exposure to antimycin and H(2)O(2) or utilizing mutants lacking mitochondrial superoxide dismutase (sod2Delta). Experiments were conducted with strains compromised in mitochondrial base excision repair (ntg1Delta) and oxidative damage resistance (pif1Delta) in order to delineate the relationship between these pathways. We observed enhanced ROS production, resulting in a direct increase in oxidative mtDNA damage and mutagenesis. Repair-deficient mutants exposed to oxidative stress conditions exhibited profound genomic instability. Elimination of Ntg1p and Pif1p resulted in a synergistic corruption of respiratory competency upon exposure to antimycin and H(2)O(2). Mitochondrial genomic integrity was substantially compromised in ntg1Delta pif1Delta sod2Delta strains, since these cells exhibit a total loss of mtDNA. A stable respiration-defective strain, possessing a normal complement of mtDNA damage resistance pathways, exhibited a complete loss of mtDNA upon exposure to antimycin and H(2)O(2). This loss was preventable by Sod2p overexpression. These results provide direct evidence that oxidative mtDNA damage can be a major contributor to mitochondrial genomic instability and demonstrate cooperation of Ntg1p and Pif1p to resist the introduction of lesions into the mitochondrial genome.

DNMR theory for ND+4ion. Pt. 1. Tunneling effects and first order approximations in quadrupole interaction

International Nuclear Information System (INIS)

Blicharski, J.S.; Lalowicz, Z.T.; Sobol, W.

1978-01-01

This work presents results of the calculations of shape of deuteron nuclear magnetic resonance for ND + 4 ion. Tunneling effect and quadrupole interaction influence considerably the line shape. (S.B.)

Multi-pathway exposure modeling of chemicals in cosmetics with application to shampoo.

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Ernstoff, Alexi S; Fantke, Peter; Csiszar, Susan A; Henderson, Andrew D; Chung, Susie; Jolliet, Olivier

2016-01-01

We present a novel multi-pathway, mass balance based, fate and exposure model compatible with life cycle and high-throughput screening assessments of chemicals in cosmetic products. The exposures through product use as well as post-use emissions and environmental media were quantified based on the chemical mass originally applied via a product, multiplied by the product intake fractions (PiF, the fraction of a chemical in a product that is taken in by exposed persons) to yield intake rates. The average PiFs for the evaluated chemicals in shampoo ranged from 3×10(-4) up to 0.3 for rapidly absorbed ingredients. Average intake rates ranged between nano- and micrograms per kilogram bodyweight per day; the order of chemical prioritization was strongly affected by the ingredient concentration in shampoo. Dermal intake and inhalation (for 20% of the evaluated chemicals) during use dominated exposure, while the skin permeation coefficient dominated the estimated uncertainties. The fraction of chemical taken in by a shampoo user often exceeded, by orders of magnitude, the aggregated fraction taken in by the population through post-use environmental emissions. Chemicals with relatively high octanol-water partitioning and/or volatility, and low molecular weight tended to have higher use stage exposure. Chemicals with low intakes during use (<1%) and subsequent high post-use emissions, however, may yield comparable intake for a member of the general population. The presented PiF based framework offers a novel and critical advancement for life cycle assessments and high-throughput exposure screening of chemicals in cosmetic products demonstrating the importance of consistent consideration of near- and far-field multi-pathway exposures. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Origins of 12-Month Attachment: A Microanalysis of 4-Month Mother-Infant Interaction

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Beebe, Beatrice; Jaffe, Joseph; Markese, Sara; Buck, Karen; Chen, Henian; Cohen, Patricia; Bahrick, Lorraine; Andrews, Howard; Feldstein, Stanley

2013-01-01

A detailed microanalysis of 4-month mother-infant face-to-face communication revealed a fine-grained specification of essential communication processes that predicted 12-month insecure attachment outcomes, particularly resistant and disorganized classifications. An urban community sample of 84 dyads were videotaped at 4 months during a face-to-face interaction, and at 12 months during the Ainsworth Strange Situation. Four-month mother and infant communication modalities of attention, affect, touch, and spatial orientation were coded from split-screen videotape on a 1s time base; mother and infant facial-visual “engagement” variables were constructed. We used contingency measures (multi-level time-series modeling) to examine the dyadic temporal process over time, and specific rates of qualitative features of behavior to examine the content of behavior. Self-contingency (auto-correlation) measured the degree of stability/lability within an individual’s own rhythms of behavior; interactive contingency (lagged cross-correlation) measured adjustments of the individual’s behavior that were correlated with the partner’s previous behavior. We documented that both self- and interactive contingency, as well as specific qualitative features, of mother and infant behavior were mechanisms of attachment formation by 4 months, distinguishing 12-month insecure, resistant, and disorganized attachment classifications from secure; avoidant were too few to test. All communication modalities made unique contributions. The separate analysis of different communication modalities identified intermodal discrepancies or conflict, both intrapersonal and interpersonal, that characterized insecure dyads. Contrary to dominant theories in the literature on face-to-face interaction, measures of maternal contingent coordination with infant yielded the fewest associations with 12-month attachment, whereas mother and infant self-contingency, and infant contingent coordination with mother

Fast interactive exploration of 4D MRI flow data

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Hennemuth, A.; Friman, O.; Schumann, C.; Bock, J.; Drexl, J.; Huellebrand, M.; Markl, M.; Peitgen, H.-O.

2011-03-01

1- or 2-directional MRI blood flow mapping sequences are an integral part of standard MR protocols for diagnosis and therapy control in heart diseases. Recent progress in rapid MRI has made it possible to acquire volumetric, 3-directional cine images in reasonable scan time. In addition to flow and velocity measurements relative to arbitrarily oriented image planes, the analysis of 3-dimensional trajectories enables the visualization of flow patterns, local features of flow trajectories or possible paths into specific regions. The anatomical and functional information allows for advanced hemodynamic analysis in different application areas like stroke risk assessment, congenital and acquired heart disease, aneurysms or abdominal collaterals and cranial blood flow. The complexity of the 4D MRI flow datasets and the flow related image analysis tasks makes the development of fast comprehensive data exploration software for advanced flow analysis a challenging task. Most existing tools address only individual aspects of the analysis pipeline such as pre-processing, quantification or visualization, or are difficult to use for clinicians. The goal of the presented work is to provide a software solution that supports the whole image analysis pipeline and enables data exploration with fast intuitive interaction and visualization methods. The implemented methods facilitate the segmentation and inspection of different vascular systems. Arbitrary 2- or 3-dimensional regions for quantitative analysis and particle tracing can be defined interactively. Synchronized views of animated 3D path lines, 2D velocity or flow overlays and flow curves offer a detailed insight into local hemodynamics. The application of the analysis pipeline is shown for 6 cases from clinical practice, illustrating the usefulness for different clinical questions. Initial user tests show that the software is intuitive to learn and even inexperienced users achieve good results within reasonable processing

Determination of cross sections for 12C-nucleus interactions at 4.5 GeV/c per incident nucleon momentum

International Nuclear Information System (INIS)

Aksinenko, V.D.; Anikina, M.Kh.; Buttsev, V.S.

1980-01-01

Interactions of relativistic 12 C nuclei with C, Ne, Si, Cu, Zr pure nuclear targets haVe been studied in the SKM-200 streamer chamber. The cross sections have been determined for inelastic interactions and for the emission of at least one negative particle. An analysis of possible sources of systematic errors has been performed. A comparison is made with results of other experiments and data obtained eaplier by the SKM-200 Collaboration for 4 He-nucleus interactions

Tunneling of coupled methyl quantum rotors in 4-methylpyridine: Single rotor potential versus coupling interaction

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Khazaei, Somayeh; Sebastiani, Daniel

2017-11-01

We study the influence of rotational coupling between a pair of methyl rotators on the tunneling spectrum in condensed phase. Two interacting adjacent methyl groups are simulated within a coupled-pair model composed of static rotational potential created by the chemical environment and the interaction potential between two methyl groups. We solve the two-dimensional time-independent Schrödinger equation analytically by expanding the wave functions on the basis set of two independent free-rotor functions. We investigate three scenarios which differ with respect to the relative strength of single-rotor and coupling potential. For each scenario, we illustrate the dependence of the energy level scheme on the coupling strength. It is found that the main determinant of splitting energy levels tends to be a function of the ratio of strengths of coupling and single-rotor potential. The tunnel splitting caused by coupling is maximized for the coupled rotors in which their total hindering potential is relatively shallow. Such a weakly hindered methyl rotational potential is predicted for 4-methylpyridine at low temperature. The experimental observation of multiple tunneling peaks arising from a single type of methyl group in 4-methylpyridine in the inelastic neutron scattering spectrum is widely attributed to the rotor-rotor coupling. In this regard, using a set of first-principles calculations combined with the nudged elastic band method, we investigate the rotational potential energy surface (PES) of the coaxial pairs of rotors in 4-methylpyridine. A Numerov-type method is used to numerically solve the two-dimensional time-independent Schrödinger equation for the calculated 2D-density functional theory profile. Our computed energy levels reproduce the observed tunneling transitions well. Moreover, the calculated density distribution of the three methyl protons resembles the experimental nuclear densities obtained from the Fourier difference method. By mapping the

Analysis of the interacting partners eIF4F and 3'-CITE required for Melon necrotic spot virus cap-independent translation.

Science.gov (United States)

Miras, Manuel; Truniger, Verónica; Querol-Audi, Jordi; Aranda, Miguel A

2017-06-01

We have shown previously that the translation of Melon necrotic spot virus (MNSV, family Tombusviridae, genus Carmovirus) RNAs is controlled by a 3'-cap-independent translation enhancer (CITE), which is genetically and functionally dependent on the eukaryotic translation initiation factor (eIF) 4E. Here, we describe structural and functional analyses of the MNSV-Mα5 3'-CITE and its translation initiation factor partner. We first mapped the minimal 3'-CITE (Ma5TE) to a 45-nucleotide sequence, which consists of a stem-loop structure with two internal loops, similar to other I-shaped 3'-CITEs. UV crosslinking, followed by gel retardation assays, indicated that Ma5TE interacts in vitro with the complex formed by eIF4E + eIF4G 980-1159 (eIF4F p20 ), but not with each subunit alone or with eIF4E + eIF4G 1003-1092 , suggesting binding either through interaction with eIF4E following a conformational change induced by its binding to eIF4G 980-1159 , or through a double interaction with eIF4E and eIF4G 980-1159 . Critical residues for this interaction reside in an internal bulge of Ma5TE, so that their mutation abolished binding to eIF4E + eIF4G 1003-1092 and cap-independent translation. We also developed an in vivo system to test the effect of mutations in eIF4E in Ma5TE-driven cap-independent translation, showing that conserved amino acids in a positively charged RNA-binding motif around amino acid position 228, implicated in eIF4E-eIF4G binding or belonging to the cap-recognition pocket, are essential for cap-independent translation controlled by Ma5TE, and thus for the multiplication of MNSV. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Non-Covalent Interactions in the Crystal Structure of Methyl 4-Hydroxy-3-Nitrobenzoate

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Jim Simpson

2012-06-01

Full Text Available Methyl 4-hydroxy-3-nitrobenzoate, (I, C8H7NO5, crystallizes with two unique molecules, A and B, in the asymmetric unit of the triclinic unit cell. The space group was assigned as P-1, with lattice parameters a = 0.72831(15, b = 1.0522(2, c = 1.1410(2 nm, α = 83.38(3, β = 80.83(3, γ = 82.02(3°, Z = 4, V = 0.8510(3 nm3, Mr = 197.15, Dc = 1.539 g/m3, µ= 0.131 mm−1, F(000 = 408, R = 0.1002 and wR = 0.2519. In the crystal structure, 12 hydrogen bonding and two p-stacking interactions link the molecules into infinite stacked sheets parallel to (101.

Spectral-fluorescent study of the interaction of the polymethine dye probe Cyan 2 with chondroitin-4-sulfate

Science.gov (United States)

Tatikolov, Alexander S.; Akimkin, Timofey M.; Panova, Ina G.; Yarmoluk, Sergiy M.

2017-04-01

The noncovalent interaction of the polymethine dye probe 3,3‧,9-trimethylthiacarbocyanine iodide (Cyan 2) with chondroitin-4-sulfate (C4S) in buffer solutions with different pH and in water in the absence of buffers has been studied by spectral-fluorescent methods. It has been shown that in all media studied, at relatively high concentrations, the dye is bound to C4S mainly as a monomer, which is accompanied by a steep rise of fluorescence (the intermediate formation of dye aggregates on the biopolymer is also observed). From the dependence of the fluorescence quantum yield on the concentration of C4S, the parameters of binding of the dye monomer to C4S were obtained: the effective binding constant K, the number of the monomeric C4S units n per one dye monomer bound to C4S, and the fluorescence quantum yield of the bound dye monomer Φfb. The dependence of Φfb (and K) on pH of the medium is not monotonic: it has a minimum in the region of neutral pH and a growth in the regions of acid and basic pH. This can be explained by changing the charge of a C4S macromolecule as a function of pH and related conformational alterations in the biopolymer, which can affect the rigidity of a dye molecule and the energy of its interaction with the biopolymer.

Di-ureasil hybrids doped with LiBF{sub 4}: Spectroscopic study of the ionic interactions and hydrogen bonding

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Mariana [Departamento de Quimica/CQ-VR, Universidade de Tras-os-Montes e Alto Douro, 5001-801 Vila Real (Portugal); Barbosa, Paula C.; Manuela Silva, M.; Smith, Michael J. [Departamento de Quimica/Centro de Quimica, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Zea Bermudez, Veronica de, E-mail: vbermude@utad.pt [Departamento de Quimica/CQ-VR, Universidade de Tras-os-Montes e Alto Douro, 5001-801 Vila Real (Portugal)

2011-09-15

Highlights: {yields} FT-IR and FT-Raman spectroscopy were used to characterize cation interactions in two LiBF{sub 4}-doped di-ureasil networks incorporating POE chains with different length. {yields} Over the range of salt content analyzed the cations bond to amorphous POE chains and form ion contact pairs with BF{sub 4}{sup -}. {yields} A crystalline POE/LiBF{sub 4} complex of unknown stoichiometry emerges at high salt concentration. - Abstract: In the present work Fourier transform infrared and Raman spectroscopy were used to characterize the cation/polymer, cation/cross-link, cation/anion and hydrogen bonding interactions in hybrid electrolytes composed of lithium tetrafluoroborate (LiBF{sub 4}) and di-urea cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks (di-ureasils) designated as d-U(2000) and d-U(600) and incorporating polyether chains with ca. 40.5 and 8.5 oxyethylene repeat units, respectively. Samples with {infinity} > n {>=} 2.5 (where n, composition, is the molar ratio of CH{sub 2}CH{sub 2}O units per Li{sup +} ion) were analyzed. In both di-ureasil systems over the whole range of salt content examined the Li{sup +} ions bond to the ether oxygen atoms of amorphous POE chains and to BF{sub 4}{sup -} ions forming ion contact pairs. Spectroscopic evidences and SEM images confirm the presence of a crystalline POE/LiBF{sub 4} complex of unknown stoichiometry at n < 20 and 25, respectively. Ionic association is particularly important in the case of the d-U(600)-based materials, as a result of the presence of strong hydrogen-bonded aggregates that prevent the establishment of Li{sup +}/urea carbonyl oxygen atom interactions.

Bacteriophytochromes control conjugation in Agrobacterium fabrum.

Science.gov (United States)

Bai, Yingnan; Rottwinkel, Gregor; Feng, Juan; Liu, Yiyao; Lamparter, Tilman

2016-08-01

Bacterial conjugation, the transfer of single stranded plasmid DNA from donor to recipient cell, is mediated through the type IV secretion system. We performed conjugation assays using a transmissible artificial plasmid as reporter. With this assay, conjugation in Agrobacterium fabrum was modulated by the phytochromes Agp1 and Agp2, photoreceptors that are most sensitive in the red region of visible light. In conjugation studies with wild-type donor cells carrying a pBIN-GUSINT plasmid as reporter that lacked the Ti (tumor inducing) plasmid, no conjugation was observed. When either agp1(-) or agp2(-) knockout donor strains were used, plasmid DNA was delivered to the recipient, indicating that both phytochromes suppress conjugation in the wild type donor. In the recipient strains, the loss of Agp1 or Agp2 led to diminished conjugation. When wild type cells with Ti plasmid and pBIN-GUS reporter plasmid were used as donor, a high rate of conjugation was observed. The DNA transfer was down regulated by red or far-red light by a factor of 3.5. With agp1(-) or agp2(-) knockout donor cells, conjugation in the dark was about 10 times lower than with the wild type donor, and with the double knockout donor no conjugation was observed. These results imply that the phytochrome system has evolved to inhibit conjugation in the light. The decrease of conjugation under different temperature correlated with the decrease of phytochrome autophosphorylation. Copyright © 2015 Elsevier B.V. All rights reserved.

UV-A/blue-light responses in algae

Energy Technology Data Exchange (ETDEWEB)

Senger, H.; Hermsmeier, D. [Philipps-Universitaet Marburg (Germany)

1994-12-31

All life on earth depends on light. A variety of photoreceptors capture the light for a wide range of reactions. Photosynthetic organisms absorb the light necessary for energy transformation and charge separation facilitating photosynthesis. In addition to the bulk pigments there are a great diversity of photoreceptors present in minute concentrations that control development, metabolism and orientation of plants and microorganisms. Based on its spectral absorbance, the well-studied phytochrome system acts in the RL region as well as in the UV-A/BL region where the above mentioned reactions are mediated by a variety of photoreceptors whose natures are largely unknown. Phyllogenetically the UV-A/BL photoreceptors seem to be more ancient pigments that eventually were replaced by the phytochrome system. However, there are many reports that suggest a coaction between the UV-A/BL receptors and the phytochrome system. In several cases the UV-A/BL activation is the prerequisite for the phytochrome reaction. Historically it was the German botanist Julius Sachs who first discovered in 1864 that phototropism in plants was due to BL reactions. It took over 70 years until Bunning (1937) and Galston and Baker (1949) rediscovered the BL response. Since then, an ever-increasing attention has been paid to this effect. Two international conferences in 1979 and 1983 have been entirely dedicated to the BL phenomenon. In this contribution, the general aspect of UV-A/BL responses and especially the responsiveness of algae will be covered. There are numerous review articles covering the various aspects of UV-A/BL action and the photoreceptors involved.

Fermi Surface of Sr_{2}RuO_{4}: Spin-Orbit and Anisotropic Coulomb Interaction Effects.

Science.gov (United States)

Zhang, Guoren; Gorelov, Evgeny; Sarvestani, Esmaeel; Pavarini, Eva

2016-03-11

The topology of the Fermi surface of Sr_{2}RuO_{4} is well described by local-density approximation calculations with spin-orbit interaction, but the relative size of its different sheets is not. By accounting for many-body effects via dynamical mean-field theory, we show that the standard isotropic Coulomb interaction alone worsens or does not correct this discrepancy. In order to reproduce experiments, it is essential to account for the Coulomb anisotropy. The latter is small but has strong effects; it competes with the Coulomb-enhanced spin-orbit coupling and the isotropic Coulomb term in determining the Fermi surface shape. Its effects are likely sizable in other correlated multiorbital systems. In addition, we find that the low-energy self-energy matrix-responsible for the reshaping of the Fermi surface-sizably differs from the static Hartree-Fock limit. Finally, we find a strong spin-orbital entanglement; this supports the view that the conventional description of Cooper pairs via factorized spin and orbital part might not apply to Sr_{2}RuO_{4}.

Direct interaction of the Golgi V-ATPase a-subunit isoform with PI(4)P drives localization of Golgi V-ATPases in yeast.

Science.gov (United States)

Banerjee, Subhrajit; Kane, Patricia M

2017-09-15

Luminal pH and phosphoinositide content are fundamental features of organelle identity. Vacuolar H + -ATPases (V-ATPases) drive organelle acidification in all eukaryotes, and membrane-bound a-subunit isoforms of the V-ATPase are implicated in organelle-specific targeting and regulation. Earlier work demonstrated that the endolysosomal lipid PI(3,5)P 2 activates V-ATPases containing the vacuolar a-subunit isoform in Saccharomyces cerevisiae Here we demonstrate that PI(4)P, the predominant Golgi phosphatidylinositol (PI) species, directly interacts with the cytosolic amino terminal (NT) domain of the yeast Golgi V-ATPase a-isoform Stv1. Lysine-84 of Stv1NT is essential for interaction with PI(4)P in vitro and in vivo, and interaction with PI(4)P is required for efficient localization of Stv1-containing V-ATPases. The cytosolic NT domain of the human V-ATPase a2 isoform specifically interacts with PI(4)P in vitro, consistent with its Golgi localization and function. We propose that NT domains of V o a-subunit isoforms interact specifically with PI lipids in their organelles of residence. These interactions can transmit organelle-specific targeting or regulation information to V-ATPases. © 2017 Banerjee and Kane. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

ADAM2 interactions with mouse eggs and cell lines expressing α4/α9 (ITGA4/ITGA9 integrins: implications for integrin-based adhesion and fertilization.

Directory of Open Access Journals (Sweden)

Ulyana V Desiderio

2010-10-01

Full Text Available Integrins are heterodimeric cell adhesion molecules, with 18 α (ITGA and eight β (ITGB subunits forming 24 heterodimers classified into five families. Certain integrins, especially the α(4/α(9 (ITGA4/ITGA9 family, interact with members of the ADAM (a disintegrin and metalloprotease family. ADAM2 is among the better characterized and also of interest because of its role in sperm function. Having shown that ITGA9 on mouse eggs participates in mouse sperm-egg interactions, we sought to characterize ITGA4/ITGA9-ADAM2 interactions.An anti-β(1/ITGB1 function-blocking antibody that reduces sperm-egg binding significantly inhibited ADAM2 binding to mouse eggs. Analysis of integrin subunit expression indicates that mouse eggs could express at least ten different integrins, five in the RGD-binding family, two in the laminin-binding family, two in the collagen-binding family, and ITGA9-ITGB1. Adhesion assays to characterize ADAM2 interactions with ITGA4/ITGA9 family members produced the surprising result that RPMI 8866 cell adhesion to ADAM2 was inhibited by an anti-ITGA9 antibody, noteworthy because ITGA9 has only been reported to dimerize with ITGB1, and RPMI 8866 cells lack detectable ITGB1. Antibody and siRNA studies demonstrate that ITGB7 is the β subunit contributing to RPMI 8866 adhesion to ADAM2.These data indicate that a novel integrin α-β combination, ITGA9-ITGB7 (α(9β(7, in RPMI 8866 cells functions as a binding partner for ADAM2. ITGA9 had previously only been reported to dimerize with ITGB1. Although ITGA9-ITGB7 is unlikely to be a widely expressed integrin and appears to be the result of "compensatory dimerization" occurring in the context of little/no ITGB1 expression, the data indicate that ITGA9-ITGB7 functions as an ADAM binding partner in certain cellular contexts, with implications for mammalian fertilization and integrin function.

Use of 1–4 interaction scaling factors to control the conformational equilibrium between α-helix and β-strand

International Nuclear Information System (INIS)

Pang, Yuan-Ping

2015-01-01

Highlights: • 1–4 interaction scaling factors are used to adjust conformational energy. • This article reports the effects of these factors on protein conformations. • Reducing these factors changes a helix to a strand in molecular dynamics simulation. • Increasing these factors causes the reverse conformational change. • These factors control the conformational equilibrium between helix and strand. - Abstract: 1–4 interaction scaling factors are used in AMBER forcefields to reduce the exaggeration of short-range repulsion caused by the 6–12 Lennard-Jones potential and a nonpolarizable charge model and to obtain better agreements of small-molecule conformational energies with experimental data. However, the effects of these scaling factors on protein secondary structure conformations have not been investigated until now. This article reports the finding that the 1–4 interactions among the protein backbone atoms separated by three consecutive covalent bonds are more repulsive in the α-helix conformation than in two β-strand conformations. Therefore, the 1–4 interaction scaling factors of protein backbone torsions ϕ and ψ control the conformational equilibrium between α-helix and β-strand. Molecular dynamics simulations confirm that reducing the ϕ and ψ scaling factors readily converts the α-helix conformation of AcO-(AAQAA) 3 -NH 2 to a β-strand conformation, and the reverse occurs when these scaling factors are increased. These results suggest that the ϕ and ψ scaling factors can be used to generate the α-helix or β-strand conformation in situ and to control the propensities of a forcefield for adopting secondary structure elements

Simulations of GCR interactions within planetary bodies using GEANT4

Science.gov (United States)

Mesick, K.; Feldman, W. C.; Stonehill, L. C.; Coupland, D. D. S.

2017-12-01

On planetary bodies with little to no atmosphere, Galactic Cosmic Rays (GCRs) can hit the body and produce neutrons primarily through nuclear spallation within the top few meters of the surfaces. These neutrons undergo further nuclear interactions with elements near the planetary surface and some will escape the surface and can be detected by landed or orbiting neutron radiation detector instruments. The neutron leakage signal at fast neutron energies provides a measure of average atomic mass of the near-surface material and in the epithermal and thermal energy ranges is highly sensitive to the presence of hydrogen. Gamma-rays can also escape the surface, produced at characteristic energies depending on surface composition, and can be detected by gamma-ray instruments. The intra-nuclear cascade (INC) that occurs when high-energy GCRs interact with elements within a planetary surface to produce the leakage neutron and gamma-ray signals is highly complex, and therefore Monte Carlo based radiation transport simulations are commonly used for predicting and interpreting measurements from planetary neutron and gamma-ray spectroscopy instruments. In the past, the simulation code that has been widely used for this type of analysis is MCNPX [1], which was benchmarked against data from the Lunar Neutron Probe Experiment (LPNE) on Apollo 17 [2]. In this work, we consider the validity of the radiation transport code GEANT4 [3], another widely used but open-source code, by benchmarking simulated predictions of the LPNE experiment to the Apollo 17 data. We consider the impact of different physics model options on the results, and show which models best describe the INC based on agreement with the Apollo 17 data. The success of this validation then gives us confidence in using GEANT4 to simulate GCR-induced neutron leakage signals on Mars in relevance to a re-analysis of Mars Odyssey Neutron Spectrometer data. References [1] D.B. Pelowitz, Los Alamos National Laboratory, LA-CP-05

Regulatory CD4 T cells inhibit HIV-1 expression of other CD4 T cell subsets via interactions with cell surface regulatory proteins.

Science.gov (United States)

Zhang, Mingce; Robinson, Tanya O; Duverger, Alexandra; Kutsch, Olaf; Heath, Sonya L; Cron, Randy Q

2018-03-01

During chronic HIV-1 infection, regulatory CD4 T cells (Tregs) frequently represent the largest subpopulation of CD4 T cell subsets, implying relative resistant to HIV-1. When HIV-1 infection of CD4 T cells was explored in vitro and ex vivo from patient samples, Tregs possessed lower levels of HIV-1 DNA and RNA in comparison with conventional effector and memory CD4 T cells. Moreover, Tregs suppressed HIV-1 expression in other CD4 T cells in an in vitro co-culture system. This suppression was mediated in part via multiple inhibitory surface proteins expressed on Tregs. Antibody blockade of CTLA-4, PD-1, and GARP on Tregs resulted in increased HIV-1 DNA integration and mRNA expression in neighboring CD4 T cells. Moreover, antibody blockade of Tregs inhibitory proteins resulted in increased HIV-1 LTR transcription in co-cultured CD4 T cells. Thus, Tregs inhibit HIV-1 infection of other CD4 T cell subsets via interactions with inhibitory cell surface proteins. Copyright © 2018 Elsevier Inc. All rights reserved.

β4 systematics in rare-earth and actinide nuclei: sdg interacting boson model description

International Nuclear Information System (INIS)

Devi, Y.D.; Kota, V.K.B.

1992-01-01

The observed variation of hexadecupole deformation parameter β 4 with mass number A in rare-earth and actinide nuclei is studied in the sdg interacting boson model (IBM) using single j-shell Otsuka-Arima-Iachello mapped and IBM-2 to IBM-1 projected hexadecupole transition operator together with SU sdg (3) and SU sdg (5) coherent states. The SU sdg (3) limit is found to provide a good description of data

Mvox: Interactive 2-4D medical image and graphics visualization software

DEFF Research Database (Denmark)

Bro-Nielsen, Morten

1996-01-01

Mvox is a new tool for visualization, segmentation and manipulation of a wide range of 2-4D grey level and colour images, and 3D surface graphics, which has been developed at the Department of Mathematical Modelling, Technical University of Denmark. The principal idea behind the software has been...... to provide a flexible tool that is able to handle all the kinds of data that are typically used in a research environment for medical imaging and visualization. At the same time the software should be easy to use and have a consistent interface providing locally only the functions relevant to the context....... This has been achieved by using Unix standards such as X/Motif/OpenGL and conforming to modern standards of interactive windowed programs...

Inhibition of HCV replication by oxysterol-binding protein-related protein 4 (ORP4 through interaction with HCV NS5B and alteration of lipid droplet formation.

Directory of Open Access Journals (Sweden)

In-Woo Park

Full Text Available Hepatitis C virus (HCV RNA replication involves complex interactions among the 3'x RNA element within the HCV 3' untranslated region, viral and host proteins. However, many of the host proteins remain unknown. In this study, we devised an RNA affinity chromatography /2D/MASS proteomics strategy and identified nine putative 3' X-associated host proteins; among them is oxysterol-binding protein-related protein 4 (ORP4, a cytoplasmic receptor for oxysterols. We determined the relationship between ORP4 expression and HCV replication. A very low level of constitutive ORP4 expression was detected in hepatocytes. Ectopically expressed ORP4 was detected in the endoplasmic reticulum and inhibited luciferase reporter gene expression in HCV subgenomic replicon cells and HCV core expression in JFH-1-infected cells. Expression of ORP4S, an ORP4 variant that lacked the N-terminal pleckstrin-homology domain but contained the C-terminal oxysterol-binding domain also inhibited HCV replication, pointing to an important role of the oxysterol-binding domain in ORP4-mediated inhibition of HCV replication. ORP4 was found to associate with HCV NS5B and its expression led to inhibition of the NS5B activity. ORP4 expression had little effect on intracellular lipid synthesis and secretion, but it induced lipid droplet formation in the context of HCV replication. Taken together, these results demonstrate that ORP4 is a negative regulator of HCV replication, likely via interaction with HCV NS5B in the replication complex and regulation of intracellular lipid homeostasis. This work supports the important role of lipids and their metabolism in HCV replication and pathogenesis.

Toxicity assessment of 4-chlorophenol to aerobic granular sludge and its interaction with extracellular polymeric substances

Energy Technology Data Exchange (ETDEWEB)

Wei, Dong; Wang, Yifan; Wang, Xiaodong; Li, Mengting; Han, Fei; Ju, Luyu; Zhang, Ge; Shi, Li; Li, Kai; Wang, Bingfeng [School of Resources and Environmental Sciences, University of Jinan, Jinan 250022 (China); Du, Bin, E-mail: dubin61@gmail.com [School of Resources and Environmental Sciences, University of Jinan, Jinan 250022 (China); Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Wei, Qin [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

2015-05-30

Highlights: • Toxicity of 4-CP to aerobic granular sludge process was evaluated. • 3D-EEM characterized the interaction between EPS and 4-CP. • Tryptophan was the main substance result in fluorescence quenching. • The mechanism of fluorescence quenching belongs to static quenching. - Abstract: The main objective of this study was to evaluate the toxicity of 4-chlorophenol (4-CP) to aerobic granular sludge in the process of treating ammonia rich wastewater. In the short-term exposure of 4-CP of 5 and 10 mg/L, ammonia nitrogen removal efficiencies in the batch reactors decreased to 87.18 ± 2.81 and 41.16 ± 3.55%, which were remarkably lower than that of control experiment (99.83 ± 0.54%). Correspondingly, the respirometric activities of heterotrophic and autotrophic bacteria of aerobic granular sludge were significantly inhibited in the presence of 4-CP. Moreover, the main components of extracellular polymeric substances (EPS) including polysaccharides and proteins increased from 18.74 ± 0.29 and 22.57 ± 0.34 mg/g SS to 27.79 ± 0.51 and 24.69 ± 0.38 mg/g SS, respectively, indicating that the presence of 4-CP played an important role on the EPS production. Three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy further showed that the intensities of EPS samples were obviously quenched with the increased of 4-CP concentrations. To be more detailed, synchronous fluorescence spectra indicated that the interaction between EPS and 4-CP was mainly caused by tryptophan residues. The mechanism of fluorescence quenching belongs to static quenching with a formation constant (K{sub A}) of 0.07 × 10{sup 4} L/mol, implying the strong formation of EPS and 4-CP complex. The results could provide reliable and accurate information to determine the potential toxicity of 4-CP on the performance of aerobic granular sludge system.

Rab5 Enhances Classical Swine Fever Virus Proliferation and Interacts with Viral NS4B Protein to Facilitate Formation of NS4B Related Complex

Directory of Open Access Journals (Sweden)

Jihui Lin

2017-08-01

Full Text Available Classical swine fever virus (CSFV is a fatal pig pestivirus and causes serious financial losses to the pig industry. CSFV NS4B protein is one of the most important viral replicase proteins. Rab5, a member of the small Rab GTPase family, is involved in infection and replication of numerous viruses including hepatitis C virus and dengue virus. Until now, the effects of Rab5 on the proliferation of CSFV are poorly defined. In the present study, we showed that Rab5 could enhance CSFV proliferation by utilizing lentivirus-mediated constitutive overexpression and eukaryotic plasmid transient overexpression approaches. On the other hand, lentivirus-mediated short hairpin RNA knockdown of Rab5 dramatically inhibited virus production. Co-immunoprecipitation, glutathione S-transferase pulldown and laser confocal microscopy assays further confirmed the interaction between Rab5 and CSFV NS4B protein. In addition, intracellular distribution of NS4B-Red presented many granular fluorescent signals (GFS in CSFV infected PK-15 cells. Inhibition of basal Rab5 function with Rab5 dominant negative mutant Rab5S34N resulted in disruption of the GFS. These results indicate that Rab5 plays a critical role in facilitating the formation of the NS4B related complexes. Furthermore, it was observed that NS4B co-localized with viral NS3 and NS5A proteins in the cytoplasm, suggesting that NS3 and NS5A might be components of the NS4B related complex. Taken together, these results demonstrate that Rab5 positively modulates CSFV propagation and interacts with NS4B protein to facilitate the NS4B related complexes formation.

Components of the CCR4-NOT complex function as nuclear hormone receptor coactivators via association with the NRC-interacting Factor NIF-1.

Science.gov (United States)

Garapaty, Shivani; Mahajan, Muktar A; Samuels, Herbert H

2008-03-14

CCR4-NOT is an evolutionarily conserved, multicomponent complex known to be involved in transcription as well as mRNA degradation. Various subunits (e.g. CNOT1 and CNOT7/CAF1) have been reported to be involved in influencing nuclear hormone receptor activities. Here, we show that CCR4/CNOT6 and RCD1/CNOT9, members of the CCR4-NOT complex, potentiate nuclear receptor activity. RCD1 interacts in vivo and in vitro with NIF-1 (NRC-interacting factor), a previously characterized nuclear receptor cotransducer that activates nuclear receptors via its interaction with NRC. As with NIF-1, RCD1 and CCR4 do not directly associate with nuclear receptors; however, they enhance ligand-dependent transcriptional activation by nuclear hormone receptors. CCR4 mediates its effect through the ligand binding domain of nuclear receptors and small interference RNA-mediated silencing of endogenous CCR4 results in a marked decrease in nuclear receptor activation. Furthermore, knockdown of CCR4 results in an attenuated stimulation of RARalpha target genes (e.g. Sox9 and HoxA1) as shown by quantitative PCR assays. The silencing of endogenous NIF-1 also resulted in a comparable decrease in the RAR-mediated induction of both Sox9 and HoxA1. Furthermore, CCR4 associates in vivo with NIF-1. In addition, the CCR4-enhanced transcriptional activation by nuclear receptors is dependent on NIF-1. The small interference RNA-mediated knockdown of NIF-1 blocks the ligand-dependent potentiating effect of CCR4. Our results suggest that CCR4 plays a role in the regulation of certain endogenous RARalpha target genes and that RCD1 and CCR4 might mediate their function through their interaction with NIF-1.

Pump-dump-probe and pump-repump-probe ultrafast spectroscopy resolves cross section of an early ground state intermediate and stimulated emission in the photoreactions of the Pr ground state of the cyanobacterial phytochrome Cph1.

Science.gov (United States)

Fitzpatrick, Ann E; Lincoln, Craig N; van Wilderen, Luuk J G W; van Thor, Jasper J

2012-01-26

The primary photoreactions of the red absorbing ground state (Pr) of the cyanobacterial phytochrome Cph1 from Synechocystis PCC 6803 involve C15═C16 Z-E photoisomerization of its phycocyanobilin chromophore. The first observable product intermediate in pump-probe measurements of the photocycle, "Lumi-R", is formed with picosecond kinetics and involves excited state decay reactions that have 3 and 14 ps time constants. Here, we have studied the photochemical formation of the Lumi-R intermediate using multipulse picosecond visible spectroscopy. Pump-dump-probe (PDP) and pump-repump-probe (PRP) experiments were carried out by employing two femtosecond visible pulses with 1, 14, and 160 ps delays, together with a broadband dispersive visible probe. The time delays between the two excitation pulses have been selected to allow interaction with the dominant (3 and 14 ps) kinetic phases of Lumi-R formation. The frequency dependence of the PDP and PRP amplitudes was investigated at 620, 640, 660, and 680 nm, covering excited state absorption (λ(max) = 620 nm), ground state absorption (λ(max) = 660 nm), and stimulated emission (λ(max) = 680 nm) cross sections. Experimental double difference transient absorbance signals (ΔΔOD), from the PDP and PRP measurements, required corrections to remove contributions from ground state repumping. The sensitivity of the resulting ΔΔOD signals was systematically investigated for possible connectivity schemes and photochemical parameters. When applying a homogeneous (sequentially decaying) connectivity scheme in both the 3 and 14 ps kinetic phases, evidence for repumping of an intermediate that has an electronic ground state configuration (GSI) is taken from the dump-induced S1 formation with 620, 640, and 660 nm wavelengths and 1 and 14 ps repump delays. Evidence for repumping a GSI is also seen, for the same excitation wavelengths, when imposing a target connectivity scheme proposed in the literature for the 1 ps repump delay. In

Traf2 interacts with Smad4 and regulates BMP signaling pathway in MC3T3-E1 osteoblasts

International Nuclear Information System (INIS)

Shimada, Koichi; Ikeda, Kyoko; Ito, Koichi

2009-01-01

Bone morphogenetic proteins (BMPs) play important roles in osteoblast differentiation and maturation. In mammals, the BMP-induced receptor-regulated Smads form complexes with Smad4. These complexes translocate and accumulate in the nucleus, where they regulate the transcription of various target genes. However, the function of Smad4 remains unclear. We performed a yeast two-hybrid screen using Smad4 as bait and a cDNA library derived from bone marrow, to indentify the proteins interacting with Smad4. cDNA clones for Tumor necrosis factor (TNF) receptor-associated factor 2 (Traf2) were identified, and the interaction between the endogenous proteins was confirmed in the mouse osteoblast cell line MC3T3-E1. To investigate the function of Traf2, we silenced it with siRNA. The level of BMP-2 protein in the medium, the expression levels of the Bmp2 gene and BMP-induced transcription factor genes, including Runx2, Dlx5, Msx2, and Sp7, and the phosphorylated-Smad1 protein level were increased in cells transfected with Traf2 siRNA. The nuclear accumulation of Smad1 increased with TNF-α stimulation for 30 min at Traf2 silencing. These results suggest that the TNF-α-stimulated nuclear accumulation of Smad1 may be dependent on Traf2. Thus, the interaction between Traf2 and Smad4 may play a role in the cross-talk between TNF-α and BMP signaling pathways.

Cyclooxygenase-2 induction in macrophages is modulated by docosahexaenoic acid via interactions with free fatty acid receptor 4 (FFA4).

Science.gov (United States)

Li, Xinzhi; Yu, Ying; Funk, Colin D

2013-12-01

Cyclooxygenase-2 (COX-2)-derived prostaglandins are implicated in numerous inflammatory disorders. The purpose of these studies was to examine previously unexplored interactions between COX-2 induction and docosahexaenoic acid (DHA) via the free fatty acid receptor 4 (FFA4) signaling pathway in murine RAW 264.7 cells and peritoneal macrophages challenged with lipopolysaccharide (LPS). DHA dose (IC50=18 μM)- and time-dependently reduced COX-2 expression, without affecting COX-1. DHA (25 μM for 24 h) decreased LPS-induced prostaglandin E2 (PGE2) synthesis by 81%, primarily through reducing COX-2 (60%), as well as down-regulating microsomal prostaglandin E synthase-1 (46%), but independently of peroxisome proliferator-activated receptors. FFA4 knockdown abrogated DHA effects on COX-2 induction, PGE2 production, and interleukin 6 (IL-6) gene expression. In the presence of inhibitors of eicosanoid metabolism via COX-2, 12/15-lipoxygenase and CYP450s (rofecoxib (1 μM), PD146176 (2 μM), or MS-PPOH (20 μM)), DHA was still effective in attenuating COX-2 induction. Moreover, Toll-like receptor 4 signaling via Akt/JNK phosphorylation and p65 nuclear translocation was repressed by DHA-activated FFA4 coupling with β-arrestin 2, which was reversed by FFA4 knockdown. These data support DHA modulation of COX-2 expression and activity, in part, via FFA4, which provides a new mechanistic explanation for some of the anti-inflammatory effects of DHA.

Spin-wave dynamics and exchange interactions in multiferroic NdFe3(BO3)4 explored by inelastic neutron scattering

Science.gov (United States)

Golosovsky, I. V.; Ovsyanikov, A. K.; Aristov, D. N.; Matveeva, P. G.; Mukhin, A. A.; Boehm, M.; Regnault, L.-P.; Bezmaternykh, L. N.

2018-04-01

Magnetic excitations and exchange interactions in multiferroic NdFe3(BO3)4 were studied by inelastic neutron scattering in the phase with commensurate antiferromagnetic structure. The observed spectra were analyzed in the frame of the linear spin-wave theory. It was shown that only the model, which includes the exchange interactions within eight coordination spheres, describes satisfactorily all observed dispersion curves. The calculation showed that the spin-wave dynamics is governed by the strongest antiferromagnetic intra-chain interaction and three almost the same inter-chain interactions. Other interactions, including ferromagnetic exchange, appeared to be insignificant. The overall energy balance of the antiferromagnetic inter-chain exchange interactions, which couple the moments from the adjacent ferromagnetic layers as well as within a layer, stabilizes ferromagnetic arrangement in the latter. It demonstrates that the pathway geometry plays a crucial role in forming of the magnetic structure.

Chemical interaction of B4C, B, and C with Mo/Si layered structures

International Nuclear Information System (INIS)

Rooij-Lohmann, V. I. T. A. de; Veldhuizen, L. W.; Zoethout, E.; Yakshin, A. E.; Kruijs, R. W. E. van de; Thijsse, B. J.; Gorgoi, M.; Schaefers, F.; Bijkerk, F.

2010-01-01

To enhance the thermal stability, B 4 C diffusion barrier layers are often added to Mo/Si multilayer structures for extreme ultraviolet optics. Knowledge about the chemical interaction between B 4 C and Mo or Si, however is largely lacking. Therefore, the chemical processes during annealing up to 600 deg. C of a Mo/B 4 C/Si layered structure have been investigated in situ with hard x-ray photoelectron spectroscopy and ex situ with depth profiling x-ray photoelectron spectroscopy. Mo/B/Si and Mo/C/Si structures have also been analyzed as reference systems. The chemical processes in these systems have been identified, with two stages being distinguished. In the first stage, B and C diffuse and react predominantly with Mo. MoSi x forms in the second stage. If the diffusion barrier consists of C or B 4 C, a compound forms that is stable up to the maximum probed temperature and annealing time. We suggest that the diffusion barrier function of B 4 C interlayers as reported in literature can be caused by the stability of the formed compound, rather than by the stability of B 4 C itself.

Use of 1–4 interaction scaling factors to control the conformational equilibrium between α-helix and β-strand

Energy Technology Data Exchange (ETDEWEB)

Pang, Yuan-Ping, E-mail: pang@mayo.edu

2015-02-06

Highlights: • 1–4 interaction scaling factors are used to adjust conformational energy. • This article reports the effects of these factors on protein conformations. • Reducing these factors changes a helix to a strand in molecular dynamics simulation. • Increasing these factors causes the reverse conformational change. • These factors control the conformational equilibrium between helix and strand. - Abstract: 1–4 interaction scaling factors are used in AMBER forcefields to reduce the exaggeration of short-range repulsion caused by the 6–12 Lennard-Jones potential and a nonpolarizable charge model and to obtain better agreements of small-molecule conformational energies with experimental data. However, the effects of these scaling factors on protein secondary structure conformations have not been investigated until now. This article reports the finding that the 1–4 interactions among the protein backbone atoms separated by three consecutive covalent bonds are more repulsive in the α-helix conformation than in two β-strand conformations. Therefore, the 1–4 interaction scaling factors of protein backbone torsions ϕ and ψ control the conformational equilibrium between α-helix and β-strand. Molecular dynamics simulations confirm that reducing the ϕ and ψ scaling factors readily converts the α-helix conformation of AcO-(AAQAA){sub 3}-NH{sub 2} to a β-strand conformation, and the reverse occurs when these scaling factors are increased. These results suggest that the ϕ and ψ scaling factors can be used to generate the α-helix or β-strand conformation in situ and to control the propensities of a forcefield for adopting secondary structure elements.

Social Cognition and Interaction in Chronic Users of 3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy").

Science.gov (United States)

Wunderli, Michael D; Vonmoos, Matthias; Treichler, Lorena; Zeller, Carmen; Dziobek, Isabel; Kraemer, Thomas; Baumgartner, Markus R; Seifritz, Erich; Quednow, Boris B

2018-04-01

The empathogen 3,4-methylenedioxymethamphetamine (MDMA) is the prototypical prosocial club drug inducing emotional openness to others. It has recently been shown that acutely applied 3,4-MDMA in fact enhances emotional empathy and prosocial behavior, while it simultaneously decreases cognitive empathy. However, the long-term effects of 3,4-MDMA use on socio-cognitive functions and social interactions have not been investigated yet. Therefore, we examined emotional and cognitive empathy, social decision-making, and oxytocin plasma levels in chronic 3,4-MDMA users. We tested 38 regular but recently abstinent 3,4-MDMA users and 56 3,4-MDMA-naïve controls with the Movie for the Assessment of Social Cognition, the Multifaceted Empathy Test, and the Distribution Game and the Dictator Game. Drug use was objectively quantified by 6-month hair analyses. Furthermore, oxytocin plasma levels were determined in smaller subgroups (24 3,4-MDMA users, 9 controls). 3,4-MDMA users showed superior cognitive empathy compared with controls in the Multifaceted Empathy Test (Cohen's d=.39) and in the Movie for the Assessment of Social Cognition (d=.50), but they did not differ from controls in emotional empathy. Moreover, 3,4-MDMA users acted less self-serving in the Distribution Game. However, within 3,4-MDMA users, multiple regression analyses showed that higher 3,4-MDMA concentrations in hair were associated with lower cognitive empathy (βMDMA=-.34, t=-2.12, P<.05). Oxytocin plasma concentrations did not significantly differ between both groups. We conclude that people with high cognitive empathy abilities and pronounced social motivations might be more prone to 3,4-MDMA consumption. In contrast, long-term 3,4-MDMA use might nevertheless have a detrimental effect on cognitive empathy capacity.

Theoretical insights into the interaction between RunPt13-n (n=4, 7 and 9) clusters and [BMIM]+ based ionic liquids: Effect of anion.

Science.gov (United States)

Cheng, Ping; Yang, Yongpeng; Huang, Shiping

2017-06-01

Density functional theory has been performed to systematically study the interactions between Ru n Pt 13-n (n=4, 7 and 9) clusters and [BMIM] + based ionic liquids. Ionic liquids [BMIM][Br], [BMIM][BF 4 ], [BMIM][PF 6 ], [BMIM][CF 3 SO 3 ], and [BMIM][NTf 2 ] have different effects on the stability of Ru 7 Pt 6 . Ionic liquids with median size anions of PF 6 - and CF 3 SO 3 - can better improve the stability of Ru 7 Pt 6 than those with the small anions of Br - and BF 4 - and large anion of NTf 2 - . Based on negative relaxation energies, the stabilities of Ru 4 Pt 9 , Ru 7 Pt 6 , and Ru 9 Pt 4 are all enhanced after interacting with [BMIM][CF 3 SO 3 ]. The stability enhanced degree is in agreement with the interaction strength. For Ru 7 Pt 6 -n{[BMIM][CF 3 SO 3 ]} (n=1, 2, 3, 4), the interaction between ionic liquid and cluster plays the primary role in stabilizing the cluster in Ru 7 Pt 6 -[BMIM][CF 3 SO 3 ]. With the increase of the number of [BMIM][CF 3 SO 3 ], the role of the interaction in stabilizing the cluster is getting weaker, while the role of steric protection is getting more important. Copyright © 2017 Elsevier Inc. All rights reserved.

Coffee inhibition of CYP3A4 in vitro was not translated to a grapefruit-like pharmacokinetic interaction clinically.

Science.gov (United States)

Dresser, George K; Urquhart, Brad L; Proniuk, Julianne; Tieu, Alvin; Freeman, David J; Arnold, John Malcolm; Bailey, David G

2017-10-01

Grapefruit can augment oral medication bioavailability through irreversible (mechanism-based) inhibition of intestinal CYP3A4. Supplementary data from our recent coffee-drug interaction clinical study showed some subjects had higher area under the plasma drug concentration - time curve (AUC) and plasma peak drug concentration (Cmax) of the CYP3A4 probe felodipine compared to aqueous control. It was hypothesized that coffee might interact like grapefruit in responsive individuals. Beans from six geographical locations were consistently brewed into coffee that was separated chromatographically to a methanolic fraction for in vitro inhibition testing of CYP3A4 metabolism of felodipine at 1% coffee strength. The effect of simultaneous incubation and 10-min preincubation with coffee fractions determined whether coffee had direct and mechanism-based inhibitory activity. A subsequent five-way randomized balanced controlled crossover clinical study evaluated the clinical pharmacokinetic interaction with single-dose felodipine. Grapefruit juice, water, or three of the in vitro tested coffees were ingested at 300 mL alone 1 h before and then with felodipine. In vitro, all six coffees decreased felodipine metabolism for both simultaneous and preincubation exposure compared to corresponding control. Five coffees demonstrated mechanism-based inhibition. Grapefruit increased felodipine AUC 0-8 (25 vs. 13 ng.h/mL, P coffees caused no change in these parameters compared to water. Despite high in vitro potency of CYP3A4 inhibition, the coffees did not cause a clinical pharmacokinetic interaction possibly from insufficient amount of inhibitor(s) in coffee reaching intestinal CYP3A4 during the absorption phase of felodipine. The results of this study highlight the need for follow-up clinical testing when in vitro results indicate the possibility of an interaction. © 2017 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British

The phosphomimetic mutation of syndecan-4 binds and inhibits Tiam1 modulating Rac1 activity in PDZ interaction-dependent manner.

Directory of Open Access Journals (Sweden)

Aniko Keller-Pinter

Full Text Available The small GTPases of the Rho family comprising RhoA, Rac1 and Cdc42 function as molecular switches controlling several essential biochemical pathways in eukaryotic cells. Their activity is cycling between an active GTP-bound and an inactive GDP-bound conformation. The exchange of GDP to GTP is catalyzed by guanine nucleotide exchange factors (GEFs. Here we report a novel regulatory mechanism of Rac1 activity, which is controlled by a phosphomimetic (Ser179Glu mutant of syndecan-4 (SDC4. SDC4 is a ubiquitously expressed transmembrane, heparan sulfate proteoglycan. In this study we show that the Ser179Glu mutant binds strongly Tiam1, a Rac1-GEF reducing Rac1-GTP by 3-fold in MCF-7 breast adenocarcinoma cells. Mutational analysis unravels the PDZ interaction between SDC4 and Tiam1 is indispensable for the suppression of the Rac1 activity. Neither of the SDC4 interactions is effective alone to block the Rac1 activity, on the contrary, lack of either of interactions can increase the activity of Rac1, therefore the Rac1 activity is the resultant of the inhibitory and stimulatory effects. In addition, SDC4 can bind and tether RhoGDI1 (GDP-dissociation inhibitor 1 to the membrane. Expression of the phosphomimetic SDC4 results in the accumulation of the Rac1-RhoGDI1 complex. Co-immunoprecipitation assays (co-IP-s reveal that SDC4 can form complexes with RhoGDI1. Together, the regulation of the basal activity of Rac1 is fine tuned and SDC4 is implicated in multiple ways.

The phosphomimetic mutation of syndecan-4 binds and inhibits Tiam1 modulating Rac1 activity in PDZ interaction-dependent manner.

Science.gov (United States)

Keller-Pinter, Aniko; Ughy, Bettina; Domoki, Monika; Pettko-Szandtner, Aladar; Letoha, Tamas; Tovari, Jozsef; Timar, Jozsef; Szilak, Laszlo

2017-01-01

The small GTPases of the Rho family comprising RhoA, Rac1 and Cdc42 function as molecular switches controlling several essential biochemical pathways in eukaryotic cells. Their activity is cycling between an active GTP-bound and an inactive GDP-bound conformation. The exchange of GDP to GTP is catalyzed by guanine nucleotide exchange factors (GEFs). Here we report a novel regulatory mechanism of Rac1 activity, which is controlled by a phosphomimetic (Ser179Glu) mutant of syndecan-4 (SDC4). SDC4 is a ubiquitously expressed transmembrane, heparan sulfate proteoglycan. In this study we show that the Ser179Glu mutant binds strongly Tiam1, a Rac1-GEF reducing Rac1-GTP by 3-fold in MCF-7 breast adenocarcinoma cells. Mutational analysis unravels the PDZ interaction between SDC4 and Tiam1 is indispensable for the suppression of the Rac1 activity. Neither of the SDC4 interactions is effective alone to block the Rac1 activity, on the contrary, lack of either of interactions can increase the activity of Rac1, therefore the Rac1 activity is the resultant of the inhibitory and stimulatory effects. In addition, SDC4 can bind and tether RhoGDI1 (GDP-dissociation inhibitor 1) to the membrane. Expression of the phosphomimetic SDC4 results in the accumulation of the Rac1-RhoGDI1 complex. Co-immunoprecipitation assays (co-IP-s) reveal that SDC4 can form complexes with RhoGDI1. Together, the regulation of the basal activity of Rac1 is fine tuned and SDC4 is implicated in multiple ways.

MDM2-MDM4 molecular interaction investigated by atomic force spectroscopy and surface plasmon resonance.

Science.gov (United States)

Moscetti, Ilaria; Teveroni, Emanuela; Moretti, Fabiola; Bizzarri, Anna Rita; Cannistraro, Salvatore

Murine double minute 2 (MDM2) and 4 (MDM4) are known as the main negative regulators of p53, a tumor suppressor. They are able to form heterodimers that are much more effective in the downregulation of p53. Therefore, the MDM2-MDM4 complex could be a target for promising therapeutic restoration of p53 function. To this aim, a deeper understanding of the molecular mechanisms underlining the heterodimerization is needed. The kinetic and thermodynamic characterization of the MDM2-MDM4 complex was performed with two complementary approaches: atomic force spectroscopy and surface plasmon resonance. Both techniques revealed an equilibrium dissociation constant (KD ) in the micromolar range for the MDM2-MDM4 heterodimer, similar to related complexes involved in the p53 network. Furthermore, the MDM2-MDM4 complex is characterized by a relatively high free energy, through a single energy barrier, and by a lifetime in the order of tens of seconds. New insights into the MDM2-MDM4 interaction could be highly important for developing innovative anticancer drugs focused on p53 reactivation.

Growth Inhibition of Cronobacter sakazakii in Experimentally Contaminated Powdered Infant Formula by Kefir Supernatant.

Science.gov (United States)

Kim, Dong-Hyeon; Chon, Jung-Whan; Kang, Il-Byeong; Kim, Hyunsook; Kim, Hong-Seok; Song, Kwang-Young; Seo, Kun-Ho

2015-09-01

Kefir is a type of fermented milk containing lactic and acetic acid bacteria and yeast. In this study, we evaluated the antimicrobial activity of kefir supernatant against Cronobacter sakazakii in powdered infant formula (PIF). In a spot-on-lawn test, the growth of 20 C. sakazakii strains, including 10 clinical and 10 food isolates, was completely inhibited in the presence of kefir supernatant. Significant differences in the diameters of inhibition zones were observed upon treatment with kefir compared with the results for Lactobacillus kefiri and Candida kefyr culture supernatants or solutions of lactic and acetic acid and ethyl alcohol in the agar well diffusion test (P < 0.05). The addition of 100 μl of kefir supernatant to 1 ml of nutrient broth completely inhibited the growth of C. sakazakii, as evaluated by spectrophotometry. The antimicrobial activity of kefir supernatant in experimentally contaminated PIF was also tested; we found no viable C. sakazakii cells remaining in PIF rehydrated with 30% kefir supernatant solution for 1 h, demonstrating that the antimicrobial activity of kefir supernatant against C. sakazakii could be applied in real food samples.

Interactions of Notch1 and TLR4 signaling pathways in DRG neurons of in vivo and in vitro models of diabetic neuropathy.

Science.gov (United States)

Chen, Tianhua; Li, Hao; Yin, Yiting; Zhang, Yuanpin; Liu, Zhen; Liu, Huaxiang

2017-11-02

Understanding the interactions between Notch1 and toll-like receptor 4 (TLR4) signaling pathways in the development of diabetic peripheral neuropathy may lead to interpretation of the mechanisms and novel approaches for preventing diabetic neuropathic pain. In the present study, the interactions between Notch1 and TLR4 signaling pathways were investigated by using dorsal root ganglion (DRG) from diabetic neuropathic pain rats and cultured DRG neurons under high glucose challenge. The results showed that high glucose induced not only Notch1 mRNA, HES1 mRNA, and TLR4 mRNA expression, but also Notch1 intracellular domain (NICD1) and TLR4 protein expression in DRG neurons. The proportion of NICD1-immunoreactive (IR) and TLR4-IR neurons in DRG cultures was also increased after high glucose challenge. The above alterations could be partially reversed by inhibition of either Notch1 or TLR4 signaling pathway. Inhibition of either Notch1 or TLR4 signaling pathway could improve mechanical allodynia and thermal hyperalgesia thresholds. Inhibition of Notch1 or TLR4 signaling also decreased tumor necrosis factor-α (TNF-α) levels in DRG from diabetic neuropathic rats. These data imply that the interaction between Notch1 and TLR4 signaling pathways is one of the important mechanisms in the development or progression of diabetic neuropathy.

Pionic 4f→3d transition in 181Ta, natural Re, and 209Bi and the strong interaction level shift and the strong interaction level shift and width of the pionic 3d state

International Nuclear Information System (INIS)

Konijn, J.; Panman, J.K.; Koch, J.H.; Doesburg, W. van; Ewan, G.T.; Johansson, T.; Tibell, G.; Fransson, K.; Tauscher, L.

1979-01-01

Owing to a powerful Compton-suppression technique it was possible to observe for the first time the pionic 4f→3d X-ray transition in elements heavier than A=150. The strong interaction monopole shifts epsilon 0 and widths GAMMA 0 as well as the quadrupole splitting of the 3d levels have been measured in Ta, Re and Bi. Thus in addition to the strongly shifted and broadened 5g→4f transitions, a second, strongly affected line is available for these elements. For the pionic 4f levels, standard optical potentials fit the strong interaction shifts and broadenings quite well. The now observed, deeper-lying 3d states in Ta, Re and Bi have shifts and widths that differ by a factor of 2 or more from the standard optical potential predictions. From the observed relative X-ray intensities of the pionic cascade the strong interaction widths of the 5g and 4f levels are also extracted. (Auth.)

Physicochemical properties of mixed phosphorus halides

International Nuclear Information System (INIS)

Sladkov, I.B.; Tugarinova, N.S.

1996-01-01

Certain physicochemical properties (thermodynamic characteristics at boiling point, critical constants, density of liquid on the saturation line) of mixed phosphorus halides (PI 3 , PI 2 F, PIF 2 , PI 2 Cl, PICl 2 , PI 1 Br, PIBr 2 , PIClF, PIBrCl, etc.) are determined by means of approximate methods. Reliability of the results obtained is confirmed by comparison of calculated and experimental data for phosphorus compounds of the same type. 7 refs., 3 figs., 4 tabs

Structural Fine-Tuning of MIT-Interacting Motif 2 (MIM2) and Allosteric Regulation of ESCRT-III by Vps4 in Yeast.

Science.gov (United States)

Kojima, Rieko; Obita, Takayuki; Onoue, Kousuke; Mizuguchi, Mineyuki

2016-06-05

The endosomal sorting complex required for transport (ESCRT) facilitates roles in membrane remodeling, such as multivesicular body biogenesis, enveloped virus budding and cell division. In yeast, Vps4 plays a crucial role in intraluminal vesicle formation by disassembling ESCRT proteins. Vps4 is recruited by ESCRT-III proteins to the endosomal membrane through the interaction between the microtubule interacting and trafficking (MIT) domain of Vps4 and the C-terminal MIT-interacting motif (MIM) of ESCRT-III proteins. Here, we have determined the crystal structure of Vps4-MIT in a complex with Vps20, a member of ESCRT-III, and revealed that Vps20 adopts a unique MIM2 conformation. Based on structural comparisons with other known MIM2s, we have refined the consensus sequence of MIM2. We have shown that another ESCRT-III protein, Ist1, binds to Vps4-MIT via its C-terminal MIM1 with higher affinity than Vps2, but lacks MIM2 by surface plasmon resonance. Surprisingly, the Ist1 MIM1 competed with the MIM2 of Vfa1, a regulator of Vps4, for binding to Vps4-MIT, even though these MIMs bind in non-overlapping sites on the MIT. These findings provide insight into the allosteric recognition of MIMs of ESCRT-III by Vps4 and also the regulation of ESCRT machinery at the last step of membrane remodeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hyperoxia increases the uptake of 5-fluorouracil in mammary tumors independently of changes in interstitial fluid pressure and tumor stroma

Directory of Open Access Journals (Sweden)

Salvesen Gerd S

2009-12-01

Full Text Available Abstract Background Hypoxia is associated with increased resistance to chemo- and radiation-therapy. Hyperoxic treatment (hyperbaric oxygen has previously been shown to potentiate the effect of some forms of chemotherapy, and this has been ascribed to enhanced cytotoxicity or neovascularisation. The aim of this study was to elucidate whether hyperoxia also enhances any actual uptake of 5FU (5-fluorouracil into the tumor tissue and if this can be explained by changes in the interstitium and extracellular matrix. Methods One group of tumor bearing rats was exposed to repeated hyperbaric oxygen (HBO treatment (2 bar, pO2 = 2 bar, 4 exposures à 90 min, whereas one group was exposed to one single identical HBO treatment. Animals housed under normal atmosphere (1 bar, pO2 = 0.2 bar served as controls. Three doses of 5FU were tested for dose response. Uptake of [3H]-5FU in the tumor was assessed, with special reference to factors that might have contributed, such as interstitial fluid pressure (Pif, collagen content, oxygen stress (measured as malondialdehyd levels, lymphatics and transcapillary transport in the tumors. Results The uptake of the cytostatic agent increases immediately after a single HBO treatment (more than 50%, but not 24 hours after the last repeated HBO treatment. Thus, the uptake is most likely related to the transient increase in oxygenation in the tumor tissue. Factors like tumor Pif and collagen content, which decreased significantly in the tumor interstitium after repeated HBO treatment, was without effect on the drug uptake. Conclusion We showed that hyperoxia increases the uptake of [3H]-5FU in DMBA-induced mammary tumors per se, independently of changes in Pif, oxygen stress, collagen fibril density, or transendothelial transport alone. The mechanism by which such an uptake occur is still not elucidated, but it is clearly stimulated by elevated pO2.

A specific 2,4-disubstituted-adamantane interaction with plasma-grown aluminum oxide. Inelastic-electron-tunneling spectroscopy study

NARCIS (Netherlands)

Meijer, E.W.; Raas, M.C.; Velzen, van P.N.T.

1987-01-01

The interaction of several mono- and disubstituted adamantanes with plasma-grown aluminum oxide has been studied using inelastic-electron-tunneling (IET) spectroscopy. The IET spectra evidence the chemisorption of 2,4-adamantanedione onto the aluminum oxide surface as the carboxylate anion of

High field ESR study of the pi-d interaction effect in beta-(BDA-TTP)2MCl4 (M=Fe, Ga)

Science.gov (United States)

Tokumoto, Takahisa; Vantol, J.; Brunel, L.-C.; Choi, E. S.; Brooks, J. S.; Kaihatsu, T.; Akutsu, H.; Yamada, J.

2007-03-01

Novel magnetic organic conductors with pi-d interaction have commanded attention since the discovery of field induced superconductivity. One of them, beta-(BDA-TTP)2FeCl4, has alternating donor molecules and quasi 2D electrical properties. Previous studies of electrical and magnetic properties show an M-I transition at 120K and an AF transition at TN=8.5K, suggesting an exchange interaction between the conduction electrons and the Fe^3+ d-electrons. The properties of beta-(BDA-TTP)2GaCl4 are similar with exception of the absence of the AF transition, which is apparently due to the absence of pi-d exchange interaction. We report angular/temperature dependent 240GHz quasi optical ESR measurements on both compounds to probe the magnetic properties. The Ga compound signals follow the donor molecule structure, and show no magnetic order at any temperature. The Fe compound signals are quite different from the Ga compound, and exhibit AF behavior below TN. The difference of Fe and Ga compounds will be discussed in terms of the interaction between localized and itinerant magnetic moments.

Multiplicities and forward-backward correlations in anti pp interactions at 22.4 GeV/c

International Nuclear Information System (INIS)

Boos, E.G.; Samojlov, V.V.; Tashimov, M.A.

1977-01-01

Forward-backward multiplicity correlations in anti pp -interactions at 22.4 GeV/c and multiplicities in a simple icle multiplicity distribution is divided into even and odd components, the probability of producting an odd state is found to be higher than that of producing an even state, which may be interpreted to be due to diffraction forward-backward and to everall multiplicities is discussed

Ectopic protein interactions within BRD4–chromatin complexes drive oncogenic megadomain formation in NUT midline carcinoma

OpenAIRE

Alekseyenko, Artyom A.; Walsh, Erica M.; Zee, Barry M.; Pakozdi, Tibor; Hsi, Peter; Lemieux, Madeleine E.; Dal Cin, Paola; Ince, Tan A.; Kharchenko, Peter V.; Kuroda, Mitzi I.; French, Christopher A.

2017-01-01

Chromatin factors generally act within large, multisubunit complexes; thus, identifying both their normal and aberrant interactors in cancer should provide important information regarding potential targets for therapeutic intervention. Here, we apply this principle to analysis of BRD4–NUT, a fusion oncoprotein that drives an aggressive subtype of squamous cell cancer. We identify ZNF532 as a prominent BRD4–NUT–interacting protein in an established NUT midline carcinoma patient cell line, and ...

The effect of interaction between Melanocortin-4 receptor polymorphism and dietary factors on the risk of metabolic syndrome.

Science.gov (United States)

Koochakpoor, Gelareh; Daneshpour, Maryam S; Mirmiran, Parvin; Hosseini, Seyed Ahmad; Hosseini-Esfahani, Firoozeh; Sedaghatikhayat, Bahareh; Azizi, Fereidoun

2016-01-01

Controversial data is available on the effect of the Melanocortin-4 receptor (MC4R) gene variation on metabolic syndrome (MetS) and ineffectiveness of diet in managing MetS. Effects of the interaction between MC4R polymorphism and dietary factors on MetS were investigated in this study. Subjects of this nested case-control study were selected from among participants of Tehran Lipid and Glucose Study. Each case (n = 815) was pair matched randomly with a control by age (±5 years) and sex from among those who had not developed ≥1 MetS components at the time that the corresponding case developed MetS. Dietary patterns were determined using factor analysis on 25 foods groups using a valid and reliable, 168-item semi-quantitative food frequency questionnaire (FFQ). MC4R rs12970134 were genotyped by Tetra-Primer ARMS-polymerase chain reaction analysis. Adjusted conditional logistic regression was used to estimate the interactions of SNP with quartiles of dietary factors in relation to MetS. MetS was defined by the modified National Cholesterol Education Program/Adult Treatment panel III. Two dietary patterns were extracted. The healthy dietary pattern was loaded heavily on vegetables, legumes, low fat dairy, whole grains, liquid oils and fruits; the western dietary pattern consisted of a high intake of soft drinks, fast foods, sweets, solid oils, red meats, salty snacks, refined grains, high fat dairy, tea and coffee, eggs and poultry. Among A allele carriers, being in the highest quartiles of western dietary pattern score and saturated fatty acid intake had an increased risk of MetS, compared to those in the lowest quartile (P trend = 0.007). Saturated fatty acid intake could modulate the association of A allele carriers of MC4R with MetS (P interaction = 0.03). A significant interaction was observed between rs12970134 with total fat and iron intake on the risk of abdominal obesity (P interaction < 0.05). Our findings suggest an interaction between rs

Influence of the density dependence factor in effective nucleon-nucleon forces and interaction of 4He-particles with stable nuclei

International Nuclear Information System (INIS)

Kuterbekov, K.A.; Zholdybayev, T.K.; Muchamedzhan, A.; Penionzhkevich, Yu.E.; Kukhtina, I.N.

2004-01-01

Full text: The most popular method for join analysis of experimental angular distributions (AD) and total cross sections (TCS) at low and moderate energies is semimicroscopic folding model (SFM) [1]. Since 4 He-particle is a core of exotic nuclei 6,8 He, it is topical to continue systematic investigations at various effective nucleon-nucleon forces. In [2] we investigated for the first time energy and mass dependencies of the parameters SFM at low and moderate energies. At that, as effective forces between nucleons of the colliding nuclei were used total M3Y-interaction [3] and nucleon densities calculated by the method of density functional [4]. In the present work based on SFM there were investigated influences of the density dependence factor in effective nucleon-nucleon forces (4 force options considered) on calculation of ADs and TCSs at interaction of 4 He-particles with stable nuclei (A = 12 - 208) at α-particle energies 21 - 141.5 MeV. Corresponding experimental AD and TCS data used for model verification are of high quality with low error both for angular and energy diapason. Therefore, conclusions made in the performed investigation contain important quantitative information and are valuable for consequent comparative analysis of experimental data on interaction of light exotic nuclei with stable nuclei

Inclusive neutral particle production in anti pp interactions at 22.4 GeV/c

International Nuclear Information System (INIS)

Boos, E.G.; Samojlov, V.V.; Takibaev, Zh.S.

1978-01-01

The differential distributions over longitudinal and transvers Feynman variables for inclusive γ, Ksub(s)sup(0), Λ production in anti pp interactions at 22.4 GeV/c are presented. The rapidity distributions in the c.m.s. for γ and K 0 /K 0 particles are well described by the quark-antiquark fusion model. In the central region there is some evidence for scaling behaviour of the invariant differential cross sections F for the anti pp → γ+all in the range from 22.4 GeV/c to 100 GeV/c while for the K 0 / K 0 tilde production Frises in this energy interval. A non-zero Λ polarization of -0.414+-0.206 was measured

Interaction of radium with freshwater sediments and their mineral components Pt. 4

International Nuclear Information System (INIS)

Benes, P.; Strejc, P.

1986-01-01

A radiotracer method was used for investigating the adsorption and desorption of radium on stream sediments under conditions similar to those prevailing in waste and surface waters. The effects of pH, ionic strength and Casup(2+) or SOsub(4)sup(2+) ions were studied. The results were compared with analogous data characterizing radium interaction with model solids representing components of the sediments. It was found that the adsorption affinity of the sediments for radium cannot be easily derived from their composition or other properties. No simple correlation with specific surface area, organic matter, oxidic coatings or other components of the sediments was observed. However, an exceptional role of barite (barium sulfate) in the sediments was noted. (author)

Amyloid and APOE ε4 interact to influence short-term decline in preclinical Alzheimer disease.

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Mormino, Elizabeth C; Betensky, Rebecca A; Hedden, Trey; Schultz, Aaron P; Ward, Andrew; Huijbers, Willem; Rentz, Dorene M; Johnson, Keith A; Sperling, Reisa A

2014-05-20

To examine whether β-amyloid (Aβ) and APOE ε4 status independently contribute or interact to influence longitudinal cognitive decline in clinically normal older individuals (CN). Data from 490 CNs were aggregated across 3 observational cohort studies (Harvard Aging Brain Study, Alzheimer's Disease Neuroimaging Initiative, and Australian Imaging Biomarkers and Lifestyle Study of Ageing; median age = 75.0 years, 255 female), and the contributions of APOE ε4 and Aβ on longitudinal change over a median of 1.49 years were examined. Cognitive decline was assessed with the Mini-Mental State Examination (MMSE) and Logical Memory (immediate and delayed recall scores). High Aβ participants were more likely to be APOE ε4+ than low Aβ participants. CNs who were both high Aβ and APOE ε4+ showed greater decline in Logical Memory immediate recall (p Alzheimer disease risk factors on cognitive decline in aging. © 2014 American Academy of Neurology.

Interaction of the D-isomer of 4-methylene glutamate (4-MG) with an active site thiol group of γ-glutamylcysteine synthetase (γ-GCS)

International Nuclear Information System (INIS)

Simondsen, R.P.; Meister, A.

1986-01-01

γ-GCS has an SH-group at or close to the glutamate binding site. During efforts to find a covalently bound inhibitor, the authors examined interaction of the enzyme with 4-MG with the thought that a glutamate analog with an α,β-unsaturated moiety might bind to the glutamate site and react with the active site thiol. 4-MG is not a significant substrate, but inhibits in the usual assay. Preincubation of the enzyme with DL-4-MG inactivated markedly and to about the same extent as found after preincubation with half the concentration of D-4-MG (prepared by action of glutamate decarboxylase on DL-4-MG); L-4-MG did not inactivate. Inactivation by 4-MG was decreased in the presence of L-glutamate. Inactivation by 4-MG was prevented by prior treatment of the enzyme with cystamine, which forms a disulfide with the active site thiol. After inactivation of the enzyme with 4-[2- 14 C]MG followed by separation of the enzyme by gel filtration, 0.9 mole of label was found per mole of enzyme, amino acid analysis after acid hydrolysis of the labeled enzyme gave labeled products that include the expected adduct formed by reaction of cysteine with 4-MG

Modulation of the Brd4/P-TEFb interaction by the human T-lymphotropic virus type 1 tax protein.

Science.gov (United States)

Cho, Won-Kyung; Zhou, Meisheng; Jang, Moon Kyoo; Huang, Keven; Jeong, Soo-Jin; Ozato, Keiko; Brady, John N

2007-10-01

Positive transcription elongation factor (P-TEFb), which is composed of CDK9 and cyclin T1, plays an important role in cellular and viral gene expression. Our lab has recently demonstrated that P-TEFb is required for Tax transactivation of the viral long terminal repeat (LTR). P-TEFb is found in two major complexes: the inactive form, which is associated with inhibitory subunits 7SK snRNA and HEXIM1, and the active form, which is associated with, at least in part, Brd4. In this study, we analyzed the effect of Brd4 on human T-lymphotropic virus type 1 (HTLV-1) transcription. Overexpression of Brd4 repressed Tax transactivation of the HTLV-1 LTR in a dose-dependent manner. In vitro binding studies suggest that Tax and Brd4 compete for binding to P-TEFb through direct interaction with cyclin T1. Tax interacts with cyclin T1 amino acids 426 to 533, which overlaps the region responsible for Brd4 binding. In vivo, overexpression of Tax decreased the amount of 7SK snRNA associated with P-TEFb and stimulates serine 2 phosphorylation of the RNA polymerase II carboxyl-terminal domain, suggesting that Tax regulates the functionality of P-TEFb. Our results suggest the possibility that Tax may compete and functionally substitute for Brd4 in P-TEFb regulation.

HTLV-1 specific CD8+ T cell function augmented by blockade of 2B4/CD48 interaction in HTLV-1 infection.

Directory of Open Access Journals (Sweden)

Chibueze Chioma Ezinne

Full Text Available CD8+ T cell response is important in the response to viral infections; this response though is regulated by inhibitory receptors. Expression of inhibitory receptors has been positively correlated with CD8+ T cell exhaustion; the consequent effect of simultaneous blockade of these inhibitory receptors on CD8+ T cell response in viral infections have been studied, however, the role of individual blockade of receptor-ligand pair is unclear. 2B4/CD48 interaction is involved in CD8+T cell regulation, its signal transducer SAP (signaling lymphocyte activation molecule (SLAM-associated protein is required for stimulatory function of 2B4/CD244 on lymphocytes hence, we analyzed 2B4/CD244 (natural killer cell receptor and SAP (signaling lymphocyte activation molecule(SLAM-associated protein on total CD8+ and HTLV-1 specific CD8+T cells in HTLV-1 infection and the effect of blockade of interaction with ligand CD48 on HTLV-1 specific CD8+ T cell function. We observed a high expression of 2B4/CD244 on CD8+ T cells relative to uninfected and further upregulation on HTLV-1 specific CD8+ T cells. 2B4+ CD8+ T cells exhibited more of an effector and terminally differentiated memory phenotype. Blockade of 2B4/CD48 interaction resulted in improvement in function via perforin expression and degranulation as measured by CD107a surface mobilization on HTLV-1 specific CD8+ T cells. In the light of these findings, we thus propose an inhibitory role for 2B4/CD48 interaction on CD8+T cell function.

High temperature interaction between Zircaloy-4 and stainless steel type 304

International Nuclear Information System (INIS)

Nagase, Fumihisa; Otomo, Takashi; Uetsuka, Hiroshi

2001-03-01

The chemical interactions between Zircaloy-4 and stainless steel type 304 were investigated in the temperature range from 1273 to 1573 K to obtain the basic information on the melt progress in the fuel bundle during an LWR severe accident. Reaction layers were formed at the contact interface and grew as the temperature and the time increase. The Zircaloy was preferentially dissolved by the reaction. The SEM/EDX analyses showed that the main process of the reaction was diffusion of Fe, Cr and Ni into the Zircaloy which resulted in the formation of a Zr-rich eutectic through the tested temperature range. Reaction rates for decrease in the materials thickness were evaluated and the reaction generally obeyed a parabolic rate law. The reaction rate constant was determined at every examined temperature and Arrhenius type rate equations were estimated for the temperature range. (author)

Decoding P4-ATPase substrate interactions.

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Roland, Bartholomew P; Graham, Todd R

Cellular membranes display a diversity of functions that are conferred by the unique composition and organization of their proteins and lipids. One important aspect of lipid organization is the asymmetric distribution of phospholipids (PLs) across the plasma membrane. The unequal distribution of key PLs between the cytofacial and exofacial leaflets of the bilayer creates physical surface tension that can be used to bend the membrane; and like Ca 2+ , a chemical gradient that can be used to transduce biochemical signals. PL flippases in the type IV P-type ATPase (P4-ATPase) family are the principle transporters used to set and repair this PL gradient and the asymmetric organization of these membranes are encoded by the substrate specificity of these enzymes. Thus, understanding the mechanisms of P4-ATPase substrate specificity will help reveal their role in membrane organization and cell biology. Further, decoding the structural determinants of substrate specificity provides investigators the opportunity to mutationally tune this specificity to explore the role of particular PL substrates in P4-ATPase cellular functions. This work reviews the role of P4-ATPases in membrane biology, presents our current understanding of P4-ATPase substrate specificity, and discusses how these fundamental aspects of P4-ATPase enzymology may be used to enhance our knowledge of cellular membrane biology.

Art27 interacts with GATA4, FOG2 and NKX2.5 and is a novel co-repressor of cardiac genes.

Directory of Open Access Journals (Sweden)

Daniel R Carter

Full Text Available Transcription factors play a crucial role in regulation of cardiac biology. FOG-2 is indispensable in this setting, predominantly functioning through a physical interaction with GATA-4. This study aimed to identify novel co-regulators of FOG-2 to further elaborate on its inhibitory activity on GATA-4. The Art27 transcription factor was identified by a yeast-2-hybrid library screen to be a novel FOG-2 protein partner. Characterisation revealed that Art27 is co-expressed with FOG-2 and GATA-4 throughout cardiac myocyte differentiation and in multiple structures of the adult heart. Art27 physically interacts with GATA-4, FOG-2 and other cardiac transcription factors and by this means, down-regulates their activity on cardiac specific promoters α-myosin heavy chain, atrial natriuretic peptide and B-type natriuretic peptide. Regulation of endogenous cardiac genes by Art27 was shown using microarray analysis of P19CL6-Mlc2v-GFP cardiomyocytes. Together these results suggest that Art27 is a novel transcription factor that is involved in downregulation of cardiac specific genes by physically interacting and inhibiting the activity of crucial transcriptions factors involved in cardiac biology.

Thermodynamic properties of antiferromagnetic ordered states of π -d interacting systems of κ -(BETS) 2Fe X4(X =Br ,Cl )

Science.gov (United States)

Fukuoka, Shuhei; Yamashita, Satoshi; Nakazawa, Yasuhiro; Yamamoto, Takashi; Fujiwara, Hideki; Shirahata, Takashi; Takahashi, Kazuko

2016-06-01

The results are presented for systematic heat capacity measurements of π-d interacting systems of κ -(BETS) 2Fe Br4 and κ -(BETS) 2FeC l4 [BETS = bis(ethylenedithio)tetraselenafulvalene] performed under in-plane magnetic fields. We observed sharp thermal anomalies at 2.47 K for κ -(BETS) 2FeB r4 and at 0.47 K for κ -(BETS) 2FeC l4 at 0 T that are associated with antiferromagnetic transitions of the 3 d electrons in the anion layers. From analyses of the magnetic heat capacity data, we indicate that the two compounds show unconventional thermodynamic behaviors inherent in the π-d interacting layered system. In the case of κ -(BETS) 2FeB r4 , a small hump structure was observed in the magnetic heat capacity below the transition temperature when a magnetic field was applied parallel to the a axis. In the case of κ -(BETS) 2FeC l4 , a similar hump structure was observed at 0 T that remained in the data with magnetic fields applied parallel to the a axis. We demonstrate that the temperature dependencies of the magnetic heat capacities scale well by normalizing the temperatures with dominant one-dimensional direct interactions (Jdd/kB) of each compound. The field dependencies of the transition temperatures and the hump structures are elucidated in one simple magnetic field vs temperature (H -T ) phase diagram. These results indicate that the thermodynamic features of both κ-type BETS salts are essentially equivalent, and the observed hump structures are derived from the one-dimensional Jdd interaction characters, which are still influential for magnetic features even in the long-range magnetic ordered states.

Investigation of thermoluminescence and electron-vibrational interaction parameters in SrAl2O4:Eu2+, Dy3+ phosphors

International Nuclear Information System (INIS)

Pardhi, Shilpa A.; Nair, Govind B.; Sharma, Ravi; Dhoble, S.J.

2017-01-01

Combustion synthesis method was employed for the synthesis of green-emitting monoclinic SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphors. The phase-purity of the prepared phosphors were examined using X-ray diffraction (XRD). The prepared phosphors exhibited green light emission with the peak centred at 510 nm, under 350 nm UV excitation. The excitation and emission spectra were analysed and the parameters of electron-vibrational interaction (EVI), such as the Huang–Rhys factor, effective phonon energy and zero-phonon line position were estimated using the spectrum fitting method. Thermoluminescence (TL) behaviour of the as-prepared phosphors were analysed for UV and 137 Cs γ-ray source irradiation. TL glow curves for UV-irradiated SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphors were analysed. - Highlights: • Photoluminescence and thermoluminescence properties of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors were analysed. • Electron-vibrational interaction (EVI) parameters of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors were determined. • The phosphors are found to exhibit green light emission.

Genotype by Environment Interactions in Cognitive Ability: A Survey of 14 Studies from 4 Countries covering 4 Age Groups

Science.gov (United States)

Molenaar, Dylan; van der Sluis, Sophie; Boomsma, Dorret I.; Haworth, Claire M. A.; Hewitt, John K.; Martin, Nicholas G.; Plomin, Robert; Wright, Margie J.; Dolan, Conor V.

2014-01-01

A large part of the variation in cognitive ability is known to be due to genetic factors. Researchers have tried to identify modifiers that influence the heritability of cognitive ability, indicating a genotype by environment interaction (GxE). To date, such modifiers include measured variables like income and socioeconomic status. The present paper focuses on GxE in cognitive ability where the environmental variable is an unmeasured environmental factor that is uncorrelated in family members. We examined this type of GxE in the GHCA-database (Haworth et al., 2009), which comprises data of 14 different cognition studies from 4 different countries including participants of different ages. Results indicate that for younger participants (4–13 years), the strength of E decreases across the additive genetic factor A, but that this effect reverts for older participants (17–34 years). However, a clear and general conclusion about the presence of a genuine GxE is hampered by differences between the individual studies with respect to environmental and genetic influences on cognitive ability. PMID:23397253

Harpin Hpa1 Interacts with Aquaporin PIP1;4 to Promote the Substrate Transport and Photosynthesis in Arabidopsis.

Science.gov (United States)

Li, Liang; Wang, Hao; Gago, Jorge; Cui, Haiying; Qian, Zhengjiang; Kodama, Naomi; Ji, Hongtao; Tian, Shan; Shen, Dan; Chen, Yanjuan; Sun, Fengli; Xia, Zhonglan; Ye, Qing; Sun, Wei; Flexas, Jaume; Dong, Hansong

2015-11-26

Harpin proteins produced by plant-pathogenic Gram-negative bacteria are the venerable player in regulating bacterial virulence and inducing plant growth and defenses. A major gap in these effects is plant sensing linked to cellular responses, and plant sensor for harpin Hpa1 from rice bacterial blight pathogen points to plasma membrane intrinsic protein (PIP). Here we show that Arabidopsis AtPIP1;4 is a plasma membrane sensor of Hpa1 and plays a dual role in plasma membrane permeability of CO2 and H2O. In particular, AtPIP1;4 mediates CO2 transport with a substantial contribute to photosynthesis and further increases this function upon interacting with Hpa1 at the plasma membrane. As a result, leaf photosynthesis rates are increased and the plant growth is enhanced in contrast to the normal process without Hpa1-AtPIP1;4 interaction. Our findings demonstrate the first case that plant sensing of a bacterial harpin protein is connected with photosynthetic physiology to regulate plant growth.

Molecular Interactions in 1,4-Dioxane, Tetrahydrofuran, and Ethyl Acetate Solutions of 1,1'-Bis(4-isopropyloxyacetylphenoxy)cyclohexane on Reological, Density, and Acoustic Behavior

Science.gov (United States)

Dhaduk, B. B.; Patel, Ch. B.; Parsania, P. H.

2017-12-01

Various thermo-acoustical parameters of 1,4-dioxane, tetrahydofuran and ethylacetae solutions of 1,1'-bis(4-isopropyloxyacetylphenoxy)cyclohexane were determined at different temperatures using density, viscosity and ultrasonic speed and correlated with concentration. Linear increase of ultrasonic speed, specific acoustical impedance, Rao's molar sound function, Van der Waals constant and free volume with concentration C and decreased with temperature. Linear decrease of adiabatic compressibility, internal pressure, intermolecular free path length, classical absorption coefficient, and viscous relaxation time with concentration and increased with temperature indicated existence of strong molecular interactions in solutions and further supported by positive values of solvation number. Gibbs free energy of activation decreased with C in all three systems. It is decreased with T in 1,4-dioxane, while increased in tetrahydrofuran and ethyl acetate. Both enthalpy of activation and entropy of activation are increased gradually with C in 1,4-dioxane, while they are negative and remained practically independent of concentration in 1,4-dioxane and tetrahydofuran systems.

Gene-gene interactions of IRF5, STAT4, IKZF1 and ETS1 in systemic lupus erythematosus.

Science.gov (United States)

Dang, J; Shan, S; Li, J; Zhao, H; Xin, Q; Liu, Y; Bian, X; Liu, Q

2014-06-01

Interferon (IFN) activation signaling and T helper 17 (Th17)-cell/B-cell regulation play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Several studies have provided convincing evidence that polymorphisms in IRF5, STAT4, IKZF1 and ETS1 from these pathways may be involved in SLE by affecting gene expression or epistasis. We analyzed the genetic interaction in known SLE susceptibility loci from the four genes in northern Han Chinese. A total of 946 northern Han Chinese participated in this study (370 unrelated SLE patients and 576 healthy controls). Subjects underwent genotyping for the single-nucleotide polymorphisms (SNPs) rs2004640 in IRF5, rs7574865 in STAT4, rs4917014 in IKZF1 and rs1128334 in ETS1 by use of a TaqMan SNP genotyping assay and direct sequencing. Gene-gene interaction analysis involved direct counting, multifactor dimensionality reduction (MDR) and linear regression analysis. SLE patients and controls differed in allele frequencies of rs7574865, rs1128334 (P < 0.001) and rs4917014 (P < 0.01). Direct counting revealed that the frequency of risk homozygote combinations was higher for SLE patients than controls (P < 0.01). Furthermore, 2-, 3- and 4-way gene-gene epistasis in SLE was confirmed by parametric methods and MDR analysis. Gene expression analysis partially supported the findings. Our study confirmed the association of the IFN pathway or Th17/B-cells and the pathogenesis of SLE, and gene-gene interaction in this pathway may increase the risk of SLE. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Probing the interaction between the histone methyltransferase/deacetylase subunit RBBP4/7 and the transcription factor BCL11A in epigenetic complexes.

Science.gov (United States)

Moody, Rebecca Reed; Lo, Miao-Chia; Meagher, Jennifer L; Lin, Chang-Ching; Stevers, Nicholas O; Tinsley, Samantha L; Jung, Inkyung; Matvekas, Aleksas; Stuckey, Jeanne A; Sun, Duxin

2018-02-09

The transcription factor BCL11A has recently been reported to be a driving force in triple-negative breast cancer (TNBC), contributing to the maintenance of a chemoresistant breast cancer stem cell (BCSC) population. Although BCL11A was shown to suppress γ-globin and p21 and to induce MDM2 expression in the hematopoietic system, its downstream targets in TNBC are still unclear. For its role in transcriptional repression, BCL11A was found to interact with several corepressor complexes; however, the mechanisms underlying these interactions remain unknown. Here, we reveal that BCL11A interacts with histone methyltransferase (PRC2) and histone deacetylase (NuRD and SIN3A) complexes through their common subunit, RBBP4/7. In fluorescence polarization assays, we show that BCL11A competes with histone H3 for binding to the negatively charged top face of RBBP4. To define that interaction, we solved the crystal structure of RBBP4 in complex with an N-terminal peptide of BCL11A (residues 2-16, BCL11A(2-16)). The crystal structure identifies novel interactions between BCL11A and the side of the β-propeller of RBBP4 that are not seen with histone H3. We next show that BCL11A(2-16) pulls down RBBP4, RBBP7, and other components of PRC2, NuRD, and SIN3A from the cell lysate of the TNBC cell line SUM149. Furthermore, we demonstrate the therapeutic potential of targeting the RBBP4-BCL11A binding by showing that a BCL11A peptide can decrease aldehyde dehydrogenase-positive BCSCs and mammosphere formation capacity in SUM149. Together, our findings have uncovered a previously unidentified mechanism that BCL11A may use to recruit epigenetic complexes to regulate transcription and promote tumorigenesis. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Analysis of capsid portal protein and terminase functional domains: interaction sites required for DNA packaging in bacteriophage T4.

Science.gov (United States)

Lin, H; Rao, V B; Black, L W

1999-06-04

Bacteriophage DNA packaging results from an ATP-driven translocation of concatemeric DNA into the prohead by the phage terminase complexed with the portal vertex dodecamer of the prohead. Functional domains of the bacteriophage T4 terminase and portal gene 20 product (gp20) were determined by mutant analysis and sequence localization within the structural genes. Interaction regions of the portal vertex and large terminase subunit (gp17) were determined by genetic (terminase-portal intergenic suppressor mutations), biochemical (column retention of gp17 and inhibition of in vitro DNA packaging by gp20 peptides), and immunological (co-immunoprecipitation of polymerized gp20 peptide and gp17) studies. The specificity of the interaction was tested by means of a phage T4 HOC (highly antigenicoutercapsid protein) display system in which wild-type, cs20, and scrambled portal peptide sequences were displayed on the HOC protein of phage T4. Binding affinities of these recombinant phages as determined by the retention of these phages by a His-tag immobilized gp17 column, and by co-immunoprecipitation with purified terminase supported the specific nature of the portal protein and terminase interaction sites. In further support of specificity, a gp20 peptide corresponding to a portion of the identified site inhibited packaging whereas the scrambled sequence peptide did not block DNA packaging in vitro. The portal interaction site is localized to 28 residues in the central portion of the linear sequence of gp20 (524 residues). As judged by two pairs of intergenic portal-terminase suppressor mutations, two separate regions of the terminase large subunit gp17 (central and COOH-terminal) interact through hydrophobic contacts at the portal site. Although the terminase apparently interacts with this gp20 portal peptide, polyclonal antibody against the portal peptide appears unable to access it in the native structure, suggesting intimate association of gp20 and gp17 possibly

4th International Conference on Man–Machine Interactions

CERN Document Server

Brachman, Agnieszka; Kozielski, Stanisław; Czachórski, Tadeusz

2016-01-01

This book provides an overview of the current state of research on development and application of methods, algorithms, tools and systems associated with the studies on man-machine interaction. Modern machines and computer systems are designed not only to process information, but also to work in dynamic environment, supporting or even replacing human activities in areas such as business, industry, medicine or military. The interdisciplinary field of research on man-machine interactions focuses on broad range of aspects related to the ways in which human make or use computational artifacts, systems and infrastructure.   This monograph is the fourth edition in the series and presents new concepts concerning analysis, design and evaluation of man-machine systems. The selection of high-quality, original papers covers a wide scope of research topics focused on the main problems and challenges encountered within rapidly evolving new forms of human-machine relationships. The presented material is structured into fol...

Interaction between the PH and START domains of ceramide transfer protein competes with phosphatidylinositol 4-phosphate binding by the PH domain.

Science.gov (United States)

Prashek, Jennifer; Bouyain, Samuel; Fu, Mingui; Li, Yong; Berkes, Dusan; Yao, Xiaolan

2017-08-25

De novo synthesis of the sphingolipid sphingomyelin requires non-vesicular transport of ceramide from the endoplasmic reticulum to the Golgi by the multidomain protein ceramide transfer protein (CERT). CERT's N-terminal pleckstrin homology (PH) domain targets it to the Golgi by binding to phosphatidylinositol 4-phosphate (PtdIns(4)P) in the Golgi membrane, whereas its C-terminal StAR-related lipid transfer domain (START) carries out ceramide transfer. Hyperphosphorylation of a serine-rich motif immediately after the PH domain decreases both PtdIns(4)P binding and ceramide transfer by CERT. This down-regulation requires both the PH and START domains, suggesting a possible inhibitory interaction between the two domains. In this study we show that isolated PH and START domains interact with each other. The crystal structure of a PH-START complex revealed that the START domain binds to the PH domain at the same site for PtdIns(4)P-binding, suggesting that the START domain competes with PtdIns(4)P for association with the PH domain. We further report that mutations disrupting the PH-START interaction increase both PtdIns(4)P-binding affinity and ceramide transfer activity of a CERT-serine-rich phosphorylation mimic. We also found that these mutations increase the Golgi localization of CERT inside the cell, consistent with enhanced PtdIns(4)P binding of the mutant. Collectively, our structural, biochemical, and cellular investigations provide important structural insight into the regulation of CERT function and localization. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.