The small angle x-ray scattering of globular proteins in solution during heat denaturation

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Banuelos, Jose; Urquidi, Jacob

2008-10-01

The ability of proteins to change their conformation in response to changes in their environment has consequences in biological processes like metabolism, chemical regulation in cells, and is believed to play a role in the onset of several neurodegenerative diseases. Factors such as a change in temperature, pressure, and the introduction of ions into the aqueous environment of a protein can give rise to the folding/unfolding of a protein. As a protein unfolds, the ratio of nonpolar to polar groups exposed to water changes, affecting a protein's thermodynamic properties. Using small angle x-ray scattering (SAXS), we are currently studying the intermediate protein conformations that arise during the folding/unfolding process as a function of temperature for five globular proteins. Trends in the observed intermediate structures of these globular proteins, along with correlations with data on protein thermodynamics may help elucidate shared characteristics between all proteins in the folding/unfolding process. Experimental design considerations will be discussed and preliminary results for some of these systems will be presented.

Proportionate Dwarfism in Mice Lacking Heterochromatin Protein 1 Binding Protein 3 (HP1BP3) Is Associated With Alterations in the Endocrine IGF-1 Pathway

OpenAIRE

Garfinkel, Benjamin P.; Arad, Shiri; Le, Phuong T.; Bustin, Michael; Rosen, Clifford J.; Gabet, Yankel; Orly, Joseph

2015-01-01

Heterochromatin protein 1 binding protein 3 (HP1BP3) is a recently described histone H1-related protein with roles in chromatin structure and transcriptional regulation. To explore the potential physiological role of HP1BP3, we have previously described an Hp1bp3?/? mouse model with reduced postnatal viability and growth. We now find that these mice are proportionate dwarfs, with reduction in body weight, body length, and organ weight. In addition to their small size, microcomputed tomography...

Transiently disordered tails accelerate folding of globular proteins.

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Mallik, Saurav; Ray, Tanaya; Kundu, Sudip

2017-07-01

Numerous biological proteins exhibit intrinsic disorder at their termini, which are associated with multifarious functional roles. Here, we show the surprising result that an increased percentage of terminal short transiently disordered regions with enhanced flexibility (TstDREF) is associated with accelerated folding rates of globular proteins. Evolutionary conservation of predicted disorder at TstDREFs and drastic alteration of folding rates upon point-mutations suggest critical regulatory role(s) of TstDREFs in shaping the folding kinetics. TstDREFs are associated with long-range intramolecular interactions and the percentage of native secondary structural elements physically contacted by TstDREFs exhibit another surprising positive correlation with folding kinetics. These results allow us to infer probable molecular mechanisms behind the TstDREF-mediated regulation of folding kinetics that challenge protein biochemists to assess by direct experimental testing. © 2017 Federation of European Biochemical Societies.

A replica exchange Monte Carlo algorithm for protein folding in the HP model

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Shmygelska Alena

2007-09-01

Full Text Available Abstract Background The ab initio protein folding problem consists of predicting protein tertiary structure from a given amino acid sequence by minimizing an energy function; it is one of the most important and challenging problems in biochemistry, molecular biology and biophysics. The ab initio protein folding problem is computationally challenging and has been shown to be NP MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaat0uy0HwzTfgDPnwy1egaryqtHrhAL1wy0L2yHvdaiqaacqWFneVtcqqGqbauaaa@3961@-hard even when conformations are restricted to a lattice. In this work, we implement and evaluate the replica exchange Monte Carlo (REMC method, which has already been applied very successfully to more complex protein models and other optimization problems with complex energy landscapes, in combination with the highly effective pull move neighbourhood in two widely studied Hydrophobic Polar (HP lattice models. Results We demonstrate that REMC is highly effective for solving instances of the square (2D and cubic (3D HP protein folding problem. When using the pull move neighbourhood, REMC outperforms current state-of-the-art algorithms for most benchmark instances. Additionally, we show that this new algorithm provides a larger ensemble of ground-state structures than the existing state-of-the-art methods. Furthermore, it scales well with sequence length, and it finds significantly better conformations on long biological sequences and sequences with a provably unique ground-state structure, which is believed to be a characteristic of real proteins. We also present evidence that our REMC algorithm can fold sequences which exhibit significant interaction between termini in the hydrophobic core relatively easily. Conclusion We demonstrate that REMC utilizing the pull move

Heterochromatin protein 1 (HP1a positively regulates euchromatic gene expression through RNA transcript association and interaction with hnRNPs in Drosophila.

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Lucia Piacentini

2009-10-01

Full Text Available Heterochromatin Protein 1 (HP1a is a well-known conserved protein involved in heterochromatin formation and gene silencing in different species including humans. A general model has been proposed for heterochromatin formation and epigenetic gene silencing in different species that implies an essential role for HP1a. According to the model, histone methyltransferase enzymes (HMTases methylate the histone H3 at lysine 9 (H3K9me, creating selective binding sites for itself and the chromodomain of HP1a. This complex is thought to form a higher order chromatin state that represses gene activity. It has also been found that HP1a plays a role in telomere capping. Surprisingly, recent studies have shown that HP1a is present at many euchromatic sites along polytene chromosomes of Drosophila melanogaster, including the developmental and heat-shock-induced puffs, and that this protein can be removed from these sites by in vivo RNase treatment, thus suggesting an association of HP1a with the transcripts of many active genes. To test this suggestion, we performed an extensive screening by RIP-chip assay (RNA-immunoprecipitation on microarrays, and we found that HP1a is associated with transcripts of more than one hundred euchromatic genes. An expression analysis in HP1a mutants shows that HP1a is required for positive regulation of these genes. Cytogenetic and molecular assays show that HP1a also interacts with the well known proteins DDP1, HRB87F, and PEP, which belong to different classes of heterogeneous nuclear ribonucleoproteins (hnRNPs involved in RNA processing. Surprisingly, we found that all these hnRNP proteins also bind heterochromatin and are dominant suppressors of position effect variegation. Together, our data show novel and unexpected functions for HP1a and hnRNPs proteins. All these proteins are in fact involved both in RNA transcript processing and in heterochromatin formation. This suggests that, in general, similar epigenetic mechanisms

A new crystal lattice structure of Helicobacter pylori neutrophil-activating protein (HP-NAP)

International Nuclear Information System (INIS)

Tsuruta, Osamu; Yokoyama, Hideshi; Fujii, Satoshi

2012-01-01

A new crystal lattice structure of H. pylori neutrophil-activating protein has been determined. Iron loading causes a series of conformational changes at the ferroxidase centre. A new crystal lattice structure of Helicobacter pylori neutrophil-activating protein (HP-NAP) has been determined in two forms: the native state (Apo) at 2.20 Å resolution and an iron-loaded form (Fe-load) at 2.50 Å resolution. The highly solvated packing of the dodecameric shell is suitable for crystallographic study of the metal ion-uptake pathway. Like other bacterioferritins, HP-NAP forms a spherical dodecamer with 23 symmetry including two kinds of channels. Iron loading causes a series of conformational changes of amino-acid residues (Trp26, Asp52 and Glu56) at the ferroxidase centre

A KINETIC MODEL FOR MONO-LAYER GLOBULAR PROTEIN ADSORPTION ON SOLID/LIQUID INTERFACES

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Kamal I. M. Al-Malah

2012-12-01

Full Text Available A kinetic model was derived for globular protein adsorption. The model takes into account the three possible scenarios of a protein molecule in solution, being exposed to an interface: adsorption step from the solution to the interface; the possible desorption back into the solution; and the surface-induced unfolding or spreading of the protein unto the substrate surface. A globular protein molecule is visualized as a sphere with radius D. In addition to the general case of protein adsorption, which portrays either the surface coverage (Theta or surface concentration (� as a function of the adsorption time, special cases, like equilibrium condition, lowsurface coverage, irreversible, and Langmuirian were also presented and treated in light of the derived model. The general model was simplified for each of the subset cases. The irreversibility versus reversibility of protein adsorption was discussed. The substrate surface energetics or effects are accounted for via the proposition of the percent relative change in D/V ratio for the adsorbing protein, called (D/VPRC parameter. (D/VPRC is calculated with respect to the monolayer surface concentration of protein, where the latter is given by D/Vratio. This can be used as a landmark to protein adsorption isotherms or even kinetics. This is visualized as an indicator for solid substrate effects on the adsorbing proteins. (D/VPRC can be zero (fresh monolayer, negative (aged monolayer, or positive (multi-layer. The reference surface concentration is reported for some selected proteins.

Proportionate Dwarfism in Mice Lacking Heterochromatin Protein 1 Binding Protein 3 (HP1BP3) Is Associated With Alterations in the Endocrine IGF-1 Pathway.

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Garfinkel, Benjamin P; Arad, Shiri; Le, Phuong T; Bustin, Michael; Rosen, Clifford J; Gabet, Yankel; Orly, Joseph

2015-12-01

Heterochromatin protein 1 binding protein 3 (HP1BP3) is a recently described histone H1-related protein with roles in chromatin structure and transcriptional regulation. To explore the potential physiological role of HP1BP3, we have previously described an Hp1bp3(-/-) mouse model with reduced postnatal viability and growth. We now find that these mice are proportionate dwarfs, with reduction in body weight, body length, and organ weight. In addition to their small size, microcomputed tomography analysis showed that Hp1bp3(-/-) mice present a dramatic impairment of their bone development and structure. By 3 weeks of age, mice of both sexes have severely impaired cortical and trabecular bone, and these defects persist into adulthood and beyond. Primary cultures of both osteoblasts and osteoclasts from Hp1bp3(-/-) bone marrow and splenocytes, respectively, showed normal differentiation and function, strongly suggesting that the impaired bone accrual is due to noncell autonomous systemic cues in vivo. One major endocrine pathway regulating both body growth and bone acquisition is the IGF regulatory system, composed of IGF-1, the IGF receptors, and the IGF-binding proteins (IGFBPs). At 3 weeks of age, Hp1bp3(-/-) mice exhibited a 60% reduction in circulating IGF-1 and a 4-fold increase in the levels of IGFBP-1 and IGFBP-2. These alterations were reflected in similar changes in the hepatic transcripts of the Igf1, Igfbp1, and Igfbp2 genes. Collectively, these results suggest that HP1BP3 plays a key role in normal growth and bone development by regulating transcription of endocrine IGF-1 components.

Functional and evolutionary analyses of Helicobacter pylori HP0231 (DsbK protein with strong oxidative and chaperone activity characterized by a highly diverged dimerization domain

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Katarzyna Marta Bocian-Ostrzycka

2015-10-01

Full Text Available Helicobacter pylori does not encode the classical DsbA/DsbB oxidoreductases that are crucial for oxidative folding of extracytoplasmic proteins. Instead, this microorganism encodes an untypical two proteins playing a role in disulfide bond formation – periplasmic HP0231, which structure resembles that of EcDsbC/DsbG, and its redox partner, a membrane protein HpDsbI (HP0595 with a -propeller structure. The aim of presented work was to assess relations between HP0231 structure and function.We showed that HP0231 is most closely related evolutionarily to the catalytic domain of DsbG, even though it possesses a catalytic motif typical for canonical DsbA proteins. Similarly, the highly diverged N-terminal dimerization domain is homologous to the dimerization domain of DsbG. To better understand the functioning of this atypical oxidoreductase, we examined its activity using in vivo and in vitro experiments. We found that HP0231 exhibits oxidizing and chaperone activities but no isomerizing activity, even though H. pylori does not contain a classical DsbC. We also show that HP0231 is not involved in the introduction of disulfide bonds into HcpC (Helicobacter cysteine-rich protein C, a protein involved in the modulation of the H. pylori interaction with its host. Additionally, we also constructed a truncated version of HP0231 lacking the dimerization domain, denoted HP0231m, and showed that it acts in E. coli cells in a DsbB-dependent manner. In contrast, HP0231m and classical monomeric EcDsbA (Escherichia coli DsbA protein were both unable to complement the lack of HP0231 in H. pylori cells, though they exist in oxidized forms. HP0231m is inactive in the insulin reduction assay and possesses high chaperone activity, in contrast to EcDsbA. In conclusion, HP0231 combines oxidative functions characteristic of DsbA proteins and chaperone activity characteristic of DsbC/DsbG, and it lacks isomerization activity.

Dynamics of proteins at low temperatures: fibrous vs. globular

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Foucat, L.; Renou, J.-P.; Tengroth, C.; Janssen, S.; Middendorf, H. D.

We have measured quasielastic neutron scattering from H2O-hydrated collagen and haemoglobin at Tτ>10 ps. Relative to haemoglobin, the 200-K dynamic transition is shifted upward by 20-25 K in collagen, and the T-dependence of m.-sq. displacements derived from Sqe(Q;T) suggests that in triple-helical systems there are three rather than two regimes: one up to around 120K (probably purely harmonic), an intermediate quasiharmonic region with a linear dependence up to 240K, followed by a steeper nonlinear rise similar to that in globular proteins.

Co-evolutionary constraints of globular proteins correlate with their folding rates.

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Mallik, Saurav; Kundu, Sudip

2015-08-04

Folding rates (lnkf) of globular proteins correlate with their biophysical properties, but relationship between lnkf and patterns of sequence evolution remains elusive. We introduce 'relative co-evolution order' (rCEO) as length-normalized average primary chain separation of co-evolving pairs (CEPs), which negatively correlates with lnkf. In addition to pairs in native 3D contact, indirectly connected and structurally remote CEPs probably also play critical roles in protein folding. Correlation between rCEO and lnkf is stronger in multi-state proteins than two-state proteins, contrasting the case of contact order (co), where stronger correlation is found in two-state proteins. Finally, rCEO, co and lnkf are fitted into a 3D linear correlation. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Effect of a low-frequency magnetic field on the structure of globular blood proteins

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Zalesskaya, G. A.; Ulashchik, V. S.; Mit'kovskaya, N. P.; Laskina, O. V.; Kuchinskii, A. V.

2007-09-01

We used IR Fourier absorption spectra of blood to study changes in the structure of globular blood proteins with extracorporeal autohemomagnetotherapy, used to treat ischemic heart disease. We compare the spectra of blood before and after magnetotherapy in the regions: amide I (1655 cm-1), amide II (1545 cm-1), amide III (1230-1350 cm-1), amide IV and amide V (400-700 cm-1). We have shown that pronounced changes in the spectra in the indicated regions on direct exposure of blood in vivo to a low-frequency pulsed magnetic field are connected with conformational changes in the secondary structure of globular blood proteins, which are apparent in the increase in the contribution of the α-helix conformation. We discuss the magnetotherapy-initiated appearance of new IR absorption bands at 1018 and 1038 cm-1 and an increase in the intensity of a number of other bands located in the 1000-1200 cm-1 region, which suggests a change in the concentration of some blood components.

Comparative analysis of the folding dynamics and kinetics of an engineered knotted protein and its variants derived from HP0242 of Helicobacter pylori

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Wang, Liang-Wei; Liu, Yu-Nan; Lyu, Ping-Chiang; Jackson, Sophie E.; Hsu, Shang-Te Danny

2015-09-01

Understanding the mechanism by which a polypeptide chain thread itself spontaneously to attain a knotted conformation has been a major challenge in the field of protein folding. HP0242 is a homodimeric protein from Helicobacter pylori with intertwined helices to form a unique pseudo-knotted folding topology. A tandem HP0242 repeat has been constructed to become the first engineered trefoil-knotted protein. Its small size renders it a model system for computational analyses to examine its folding and knotting pathways. Here we report a multi-parametric study on the folding stability and kinetics of a library of HP0242 variants, including the trefoil-knotted tandem HP0242 repeat, using far-UV circular dichroism and fluorescence spectroscopy. Equilibrium chemical denaturation of HP0242 variants shows the presence of highly populated dimeric and structurally heterogeneous folding intermediates. Such equilibrium folding intermediates retain significant amount of helical structures except those at the N- and C-terminal regions in the native structure. Stopped-flow fluorescence measurements of HP0242 variants show that spontaneous refolding into knotted structures can be achieved within seconds, which is several orders of magnitude faster than previously observed for other knotted proteins. Nevertheless, the complex chevron plots indicate that HP0242 variants are prone to misfold into kinetic traps, leading to severely rolled-over refolding arms. The experimental observations are in general agreement with the previously reported molecular dynamics simulations. Based on our results, kinetic folding pathways are proposed to qualitatively describe the complex folding processes of HP0242 variants.

Omnipresence of the polyproline II helix in fibrous and globular proteins.

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Esipova, Natalia G; Tumanyan, Vladimir G

2017-02-01

Left-handed helical conformation of a polypeptide chain (PPII) is the third type of the protein backbone structure. This conformation universally exists in fibrous, globular proteins, and biologically active peptides. It has unique physical and chemical properties determining a wide range of biological functions, from the protein folding to the tissue differentiation. New examples of the structure have been appearing in spite of difficulties in their detection and investigation. The annotation and prediction of the PPII was also a challenging task. Recently, many PPII motifs with new and/or unexpected functions are being accumulated in databases. In this review we describe the major structural and dynamic forms of PPII, the diversity of its functions, and the role in different biological processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Computational and theoretical studies of globular proteins

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Pagan, Daniel L.

Protein crystallization is often achieved in experiment through a trial and error approach. To date, there exists a dearth of theoretical understanding of the initial conditions necessary to promote crystallization. While a better understanding of crystallization will help to create good crystals suitable for structure analysis, it will also allow us to prevent the onset of certain diseases. The core of this thesis is to model and, ultimately, understand the phase behavior of protein particles in solution. Toward this goal, we calculate the fluid-fluid coexistence curve in the vicinity of the metastable critical point of the modified Lennard-Jones potential, where it has been shown that nucleation is increased by many orders of magnitude. We use finite-size scaling techniques and grand canonical Monte Carlo simulation methods. This has allowed us to pinpoint the critical point and subcritical region with high accuracy in spite of the critical fluctuations that hinder sampling using other Monte Carlo techniques. We also attempt to model the phase behavior of the gamma-crystallins, mutations of which have been linked to genetic cataracts. The complete phase behavior of the square well potential at the ranges of attraction lambda = 1.15 and lambda = 1.25 is calculated and compared with that of the gammaII-crystallin. The role of solvent is also important in the crystallization process and affects the phase behavior of proteins in solution. We study a model that accounts for the contribution of the solvent free-energy to the free-energy of globular proteins. This model allows us to model phase behavior that includes solvent.

The direct piezoelectric effect in the globular protein lysozyme

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Stapleton, A.; Noor, M. R.; Sweeney, J.; Casey, V.; Kholkin, A. L.; Silien, C.; Gandhi, A. A.; Soulimane, T.; Tofail, S. A. M.

2017-10-01

Here, we present experimental evidence of the direct piezoelectric effect in the globular protein, lysozyme. Piezoelectric materials are employed in many actuating and sensing applications because they can convert mechanical energy into electrical energy and vice versa. Although originally studied in inorganic materials, several biological materials including amino acids and bone, also exhibit piezoelectricity. The exact mechanisms supporting biological piezoelectricity are not known, nor is it known whether biological piezoelectricity conforms strictly to the criteria of classical piezoelectricity. The observation of piezoelectricity in protein crystals presented here links biological piezoelectricity with the classical theory of piezoelectricity. We quantify the direct piezoelectric effect in monoclinic and tetragonal aggregate films of lysozyme using conventional techniques based on the Berlincourt Method. The largest piezoelectric effect measured in a crystalline aggregate film of lysozyme was approximately 6.5 pC N-1. These findings raise fundamental questions as to the possible physiological significance of piezoelectricity in lysozyme and the potential for technical applications.

SANS study of understanding mechanism of cold gelation of globular proteins

International Nuclear Information System (INIS)

Chinchalikar, A. J.; Kumar, Sugam; Aswal, V. K.; Wagh, A. G.; Kohlbrecher, J.

2014-01-01

Small-angle neutron scattering (SANS) has been used to probe the evolution of interaction and the resultant structures in the cold gelation of globular proteins. The cold gelation involves two steps consisting of irreversible protein deformation by heating followed by some means (e.g. increasing ionic strength) to bring them together at room temperature. We have examined the role of different salts in cold gelation of preheated aqueous Bovine Serum Albumin (BSA) protein solutions. The interactions have been modeled by two Yukawa potential combining short-range attraction and long-range repulsion. We show that in step 1 (preheated temperature effect) the deformation of protein increases the magnitude of attractive interaction but not sufficient to induce gel. The attractive interaction is further enhanced in step 2 (salt effect) to result in gel formation. The salt effect is found to be strongly depending on the valency of the counterions. The gel structure has been characterized by the mass fractals

HP1γ function is required for male germ cell survival and spermatogenesis

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Brown Jeremy P

2010-04-01

Full Text Available Abstract Background HP1 proteins are conserved components of eukaryotic constitutive heterochromatin. In mammals, there are three genes that encode HP1-like proteins, termed HP1α, HP1β and HP1γ, which have a high degree of homology This paper describes for the first time, to our knowledge, the physiological function of HP1γ using a gene-targeted mouse. Results While targeting the Cbx3 gene (encoding the HP1γ protein with a conditional targeting vector, we generated a hypomorphic allele (Cbx3hypo, which resulted in much reduced (barely detectable levels of HP1γ protein. Homozygotes for the hypomorphic allele (Cbx3hypo/hypo are rare, with only 1% of Cbx3hypo/hypo animals reaching adulthood. Adult males exhibit a severe hypogonadism that is associated with a loss of germ cells, with some seminiferous tubules retaining only the supporting Sertoli cells (Sertoli cell-only phenotype. The percentage of seminiferous tubules that are positive for L1 ORF1 protein (ORF1p in Cbx3hypo/hypo testes is greater than that for wild-type testes, indicating that L1 retrotransposon silencing is reversed, leading to ectopic expression of ORF1p in Cbx3hypo/hypo germ cells. Conclusions The Cbx3 gene product (the HP1γ protein has a non-redundant function during spermatogenesis that cannot be compensated for by the other two HP1 isotypes. The Cbx3hypo/hypo spermatogenesis defect is similar to that found in Miwi2 and Dnmt3L mutants. The Cbx3 gene-targeted mice generated in this study provide an appropriate model for the study of HP1γ in transposon silencing and parental imprinting.

Proteolytic activities of kiwifruit actinidin (Actinidia deliciosa cv. Hayward) on different fibrous and globular proteins: a comparative study of actinidin with papain.

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Chalabi, Maryam; Khademi, Fatemeh; Yarani, Reza; Mostafaie, Ali

2014-04-01

Actinidin, a member of the papain-like family of cysteine proteases, is abundant in kiwifruit. To date, a few studies have been provided to investigate the proteolytic activity and substrate specificity of actinidin on native proteins. Herein, the proteolytic activity of actinidin was compared to papain on several different fibrous and globular proteins under neutral, acidic and basic conditions. The digested samples were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and densitometry to assess the proteolytic effect. Furthermore, the levels of free amino nitrogen (FAN) of the treated samples were determined using the ninhydrin colorimetric method. The findings showed that actinidin has no or limited proteolytic effect on globular proteins such as immunoglobulins including sheep IgG, rabbit IgG, chicken IgY and fish IgM, bovine serum albumin (BSA), lipid transfer protein (LTP), and whey proteins (α-lactalbumin and β-lactoglobulin) compared to papain. In contrast to globular proteins, actinidin could hydrolyze collagen and fibrinogen perfectly at neutral and mild basic pHs. Moreover, this enzyme could digest pure α-casein and major subunits of micellar casein especially in acidic pHs. Taken together, the data indicated that actinidin has narrow substrate specificity with the highest enzymatic activity for the collagen and fibrinogen substrates. The results describe the actinidin as a mild plant protease useful for many special applications such as cell isolation from different tissues and some food industries as a mixture formula with other relevant proteases.

Conformational and functional analysis of the C-terminal globular head of the reovirus cell attachment protein.

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Duncan, R; Horne, D; Strong, J E; Leone, G; Pon, R T; Yeung, M C; Lee, P W

1991-06-01

We have been investigating structure-function relationships in the reovirus cell attachment protein sigma 1 using various deletion mutants and protease analysis. In the present study, a series of deletion mutants were constructed which lacked 90, 44, 30, 12, or 4 amino acids from the C-terminus of the 455-amino acid-long reovirus type 3 (T3) sigma 1 protein. The full-length and truncated sigma 1 proteins were expressed in an in vitro transcription/translation system and assayed for L cell binding activity. It was found that the removal of as few as four amino acids from the C-terminus drastically affected the cell binding function of the sigma 1 protein. The C-terminal-truncated proteins were further characterized using trypsin, chymotrypsin, and monoclonal and polyclonal antibodies. Our results indicated that the C-terminal portions of the mutant proteins were misfolded, leading to a loss in cell binding function. The N-terminal fibrous tail of the proteins was unaffected by the deletions as was sigma 1 oligomerization, further illustrating the discrete structural and functional roles of the N- and C-terminal domains of sigma 1. In an attempt to identify smaller, functional peptides, full-length sigma 1 expressed in vitro was digested with trypsin and subsequently with chymotrypsin under various conditions. The results clearly demonstrated the highly stable nature of the C-terminal globular head of sigma 1, even when separated from the N-terminal fibrous tail. We concluded that: (1) the C-terminal globular head of sigma 1 exists as a compact, protease-resistant oligomeric structure; (2) an intact C-terminus is required for proper head folding and generation of the conformationally dependent cell binding domain.

THE PRODUCTION RATE OF SN Ia EVENTS IN GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Washabaugh, Pearce C.; Bregman, Joel N.

2013-01-01

In globular clusters, dynamical evolution produces luminous X-ray emitting binaries at a rate about 200 times greater than in the field. If globular clusters also produce SN Ia at a high rate, it would account for many of the SN Ia production in early-type galaxies and provide insight into their formation. Here we use archival Hubble Space Telescope (HST) images of nearby galaxies that have hosted an SN Ia to examine the rate at which globular clusters produce these events. The location of the SN Ia is registered on an HST image obtained before the event or after the supernova (SN) faded. Of the 36 nearby galaxies examined, 21 had sufficiently good data to search for globular cluster hosts. None of the 21 SNe have a definite globular cluster counterpart, although there are some ambiguous cases. This places an upper limit to the enhancement rate of SN Ia production in globular clusters of about 42 at the 95% confidence level, which is an order of magnitude lower than the enhancement rate for luminous X-ray binaries. Even if all of the ambiguous cases are considered as having a globular cluster counterpart, the upper bound for the enhancement rate is 82 at the 95% confidence level, still a factor of several below that needed to account for half of the SN Ia events. Barring unforeseen selection effects, we conclude that globular clusters are not responsible for producing a significant fraction of the SN Ia events in early-type galaxies.

Concurrent proinflammatory and apoptotic activity of a Helicobacter pylori protein (HP986 points to its role in chronic persistence.

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Ayesha Alvi

Full Text Available Helicobacter pylori induces cytokine mediated changes in gastroduodenal pathophysiology, wherein, the activated macrophages at the sub-mucosal space play a central role in mounting innate immune response against the antigens. The bacterium gains niche through persistent inflammation and local immune-suppression causing peptic ulcer disease or chronic gastritis; the latter being a significant risk factor for the development of gastric adenocarcinoma. What favors persistence of H. pylori in the gastric niches is not clearly understood. We report detailed characterization of a functionally unknown gene (HP986, which was detected in patient isolates associated with peptic ulcer and gastric carcinoma. Expression and purification of recombinant HP986 (rHP986 revealed a novel, ∼29 kDa protein in biologically active form which associates with significant levels of humoral immune responses in diseased individuals (p<0.001. Also, it induced significant levels of TNF-α and Interleukin-8 in cultured human macrophages concurrent to the translocation of nuclear transcription factor-κB (NF-κB. Further, the rHP986 induced apoptosis of cultured macrophages through a Fas mediated pathway. Dissection of the underlying signaling mechanism revealed that rHP986 induces both TNFR1 and Fas expression to lead to apoptosis. We further demonstrated interaction of HP986 with TNFR1 through computational and experimental approaches. Independent proinflammatory and apoptotic responses triggered by rHP986 as shown in this study point to its role, possibly as a survival strategy to gain niche through inflammation and to counter the activated macrophages to avoid clearance.

Mua (HP0868) Is a Nickel-Binding Protein That Modulates Urease Activity in Helicobacter pylori

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Benoit, Stéphane L.; Maier, Robert J.

2011-01-01

A novel mechanism aimed at controlling urease expression in Helicobacter pylori in the presence of ample nickel is described. Higher urease activities were observed in an hp0868 mutant (than in the wild type) in cells supplemented with nickel, suggesting that the HP0868 protein (herein named Mua for modulator of urease activity) represses urease activity when nickel concentrations are ample. The increase in urease activity in the Δmua mutant was linked to an increase in urease transcription and synthesis, as shown by quantitative real-time PCR, SDS-PAGE, and immunoblotting against UreAB. Increased urease synthesis was also detected in a Δmua ΔnikR double mutant strain. The Δmua mutant was more sensitive to nickel toxicity but more resistant to acid challenge than was the wild-type strain. Pure Mua protein binds 2 moles of Ni2+ per mole of dimer. Electrophoretic mobility shift assays did not reveal any binding of Mua to the ureA promoter or other selected promoters (nikR, arsRS, 5′ ureB-sRNAp). Previous yeast two-hybrid studies indicated that Mua and RpoD may interact; however, only a weak interaction was detected via cross-linking with pure components and this could not be verified by another approach. There was no significant difference in the intracellular nickel level between wild-type and mua mutant cells. Taken together, our results suggest the HP0868 gene product represses urease transcription when nickel levels are high through an as-yet-uncharacterized mechanism, thus counterbalancing the well-described NikR-mediated activation. PMID:21505055

Helicobacter pylori protein HP0986 (TieA) interacts with mouse TNFR1 and triggers proinflammatory and proapoptotic signaling pathways in cultured macrophage cells (RAW 264.7).

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Ansari, Suhail A; Devi, Savita; Tenguria, Shivendra; Kumar, Ashutosh; Ahmed, Niyaz

2014-08-01

HP0986 protein of Helicobacter pylori has been shown to trigger induction of proinflammatory cytokines (IL-8 and TNF-α) through the activation of NF-κB and also to induce Fas mediated apoptosis of human macrophage cells (THP-1). In this study, we unravel mechanistic details of the biological effects of this protein in a murine macrophage environment. Up regulation of MCP-1 and TNF-α in HP0986-induced RAW 264.7 cells occurred subsequent to the activation and translocation of NF-κB to the cell nucleus. Further, HP0986 induced apoptosis of RAW 264.7 cells through Fas activation and this was in agreement with previous observations made with THP-1 cells. Our studies indicated activation of TNFR1 through interaction with HP0986 and this elicited the aforementioned responses independent of TLR2, TLR4 or TNFR2. We found that mouse TNFR1 activation by HP0986 facilitates formation of a complex comprising of TNFR1, TRADD and TRAF2, and this occurs upstream of NF-κB activation. Furthermore, FADD also forms a second complex, at a later stage, together with TNFR1 and TRADD, resulting in caspase-8 activation and thereby the apoptosis of RAW 264.7 cells. In summary, our observations reveal finer details of the functional activity of HP0986 protein in relation to its behavior in a murine macrophage cell environment. These findings reconfirm the proinflammatory and apoptotic role of HP0986 signifying it to be an important trigger of innate responses. These observations form much needed baseline data entailing future in vivo studies of the functions of HP0986 in a murine model. Copyright © 2014 Elsevier Ltd. All rights reserved.

Small-angle X-ray scattering studies of thermally-induced globular protein gels

International Nuclear Information System (INIS)

Clark, A.H.; Tuffnell, C.D.

1980-01-01

Small-angle X-ray scattering has been applied to gels formed by heating globular proteins, in aqueous solution, above their unfolding temperatures. A number of BSA gels, previously characterised by electron microscopy, have been studied, and by setting up theoretical models for the scattering process, the X-ray data have been shown to be consistent with the microscope conclusions regarding network structure. It is concluded that the networks form by a linearly-directed aggregation of unfolded, disc-like, protein molecules, three-dimensional geometry being achieved by occasional branching, and/or cross-linking. Long-range inhomogeneities in network structure, easily observed by electron microscopy, and correlated with variations in pH or ionic strength, have an effect on X-ray scattering, and hence the X-ray method is sensitive not only to different network strand thicknesses, but to different degrees of uniformity as well. (author)

Self-assembly dynamics for the transition of a globular aggregate to a fibril network of lysozyme proteins via a coarse-grained Monte Carlo simulation

Directory of Open Access Journals (Sweden)

R. B. Pandey

2015-09-01

Full Text Available The self-organizing dynamics of lysozymes (an amyloid protein with 148 residues with different numbers of protein chains, Nc = 1,5,10, and 15 (concentration 0.004 – 0.063 is studied by a coarse-grained Monte Carlo simulation with knowledge-based residue-residue interactions. The dynamics of an isolated lysozyme (Nc = 1 is ultra-slow (quasi-static at low temperatures and becomes diffusive asymptotically on raising the temperature. In contrast, the presence of interacting proteins leads to concentration induced protein diffusion at low temperatures and concentration-tempering sub-diffusion at high temperatures. Variation of the radius of gyration of the protein with temperature shows a systematic transition from a globular structure (at low T to a random coil (high T conformation when the proteins are isolated. The crossover from globular to random coil becomes sharper upon increasing the protein concentration (i.e. with Nc = 5,10, with larger Rg at higher temperatures and concentration; Rg becomes smaller on adding more protein chains (e.g. Nc = 15 a non-monotonic response to protein concentration. Analysis of the structure factor (S(q provides an estimate of the effective dimension (D ≥ 3, globular conformation at low temperature, and D ∼ 1.7, random coil, at high temperatures of the isolated protein. With many interacting proteins, the morphology of the self-assembly varies with scale, i.e. at the low temperature (T = 0.015, D ∼ 2.9 on the scale comparable to the radius of gyration of the protein, and D ∼ 2.3 at the large scale over the entire sample. The global network of fibrils appears at high temperature (T = 0.021 with D ∼ 1.7 (i.e. a random coil morphology at large scale involving tenuous distribution of micro-globules (at small scales.

Globular clusters - Fads and fallacies

International Nuclear Information System (INIS)

White, R.E.

1991-01-01

The types of globular clusters observed in the Milky Way Galaxy are described together with their known characteristics, with special attention given to correcting the erroneous statements made earlier about globular clusters. Among these are the following statements: the Galaxy is surrounded by many hundreds of globular clusters; all globular clusters are located toward the Galactic center, all globular clusters are metal poor and move about the Galaxy in highly elliptical paths; all globular clusters contain RR Lyrae-type variable stars, and the RR Lyrae stars found outside of globulars have come from cluster dissolution or ejection; all of the stars in a given cluster were born at the same time and have the same chemical composition; X-ray globulars are powered by central black holes; and the luminosity functions for globular clusters are well defined and well determined. Consideration is given to the fact that globular clusters in the Magellanic Clouds differ from those in the Milky Way by their age distribution and that the globulars of the SMC differ from those of the LMC

AFM-based identification of the dynamic properties of globular proteins: simulation study

International Nuclear Information System (INIS)

Kim, Deok Ho; Park, Jung Yul; Kim, Moon K.; Hong, Keum Shik

2008-01-01

Nowadays a mathematical model-based computational approach is getting more attention as an effective tool for understanding the mechanical behaviors of biological systems. To find the mechanical properties of the proteins required to build such a model, this paper investigates a real-time identification method based on an AFM nanomanipulation system. First, an AFM-based bio-characterization system is introduced. Second, a second-order time-varying linear model representing the interaction between an AFM cantilever and globular proteins in a solvent is presented. Finally, we address a real-time estimation method in which the results of AFM experiments are designed to be inputs of the state estimator proposed here. Our attention is restricted to a theoretical feasibility analysis of the proposed methodology. We simply set the mechanical properties of the particular protein such as mass, stiffness, and damping coefficient in the system model prior to running the simulation. Simulation results show very good agreement with the preset properties. We anticipate that the realization of the AFM-based bio-characterization system will also provide an experimental validation of the proposed identification procedure in the future. This methodology can be used to determine a model of protein motion for the purpose of computer simulation and for a real-time modification of protein deformation

Pulmonary haptoglobin (pHp) is part of the surfactant system in the human lung.

Science.gov (United States)

Abdullah, Mahdi; Goldmann, Torsten

2012-11-20

Since the existence of pHp was demonstrated, it has been shown that this molecule and its receptor CD163 are regulated by different stimuli. Furthermore, a comparably fast secretion of pHp was described as well as the immuno-stimulatory effects. The intention of this study was to elucidate the role of pHp in the human lungs further. Here we show, by means of confocal microscopy and immune-electron-microscopy, a clear co-localization of pHp with surfactant protein-B in lamellar bodies of alveolar epithelial cells type II. These results are underlined by immunohistochemical stainings in differently fixed human lung tissues, which show pHp in vesicular and released form. The images of the released form resemble the intended position of surfactant in the human alveolus. pHp is secreted by Alveolar epithelial cells type II as previously shown. Moreover, pHp is co-localized with Surfactant protein-B. We conclude that the presented data shows that pHp is a native part of the surfactant system in the human lung. http://www.diagnosticpathology.diagnomx.eu/vs/2563584738239912.

The nature of folded states of globular proteins.

Science.gov (United States)

Honeycutt, J D; Thirumalai, D

1992-06-01

We suggest, using dynamical simulations of a simple heteropolymer modelling the alpha-carbon sequence in a protein, that generically the folded states of globular proteins correspond to statistically well-defined metastable states. This hypothesis, called the metastability hypothesis, states that there are several free energy minima separated by barriers of various heights such that the folded conformations of a polypeptide chain in each of the minima have similar structural characteristics but have different energies from one another. The calculated structural characteristics, such as bond angle and dihedral angle distribution functions, are assumed to arise from only those configurations belonging to a given minimum. The validity of this hypothesis is illustrated by simulations of a continuum model of a heteropolymer whose low temperature state is a well-defined beta-barrel structure. The simulations were done using a molecular dynamics algorithm (referred to as the "noisy" molecular dynamics method) containing both friction and noise terms. It is shown that for this model there are several distinct metastable minima in which the structural features are similar. Several new methods of analyzing fluctuations in structures belonging to two distinct minima are introduced. The most notable one is a dynamic measure of compactness that can in principle provide the time required for maximal compactness to be achieved. The analysis shows that for a given metastable state in which the protein has a well-defined folded structure the transition to a state of higher compactness occurs very slowly, lending credence to the notion that the system encounters a late barrier in the process of folding to the most compact structure. The examination of the fluctuations in the structures near the unfolding----folding transition temperature indicates that the transition state for the unfolding to folding process occurs closer to the folded state.

The HP0256 gene product is involved in motility and cell envelope architecture of Helicobacter pylori

LENUS (Irish Health Repository)

Douillard, Francois P

2010-04-08

Abstract Background Helicobacter pylori is the causative agent for gastritis, and peptic and duodenal ulcers. The bacterium displays 5-6 polar sheathed flagella that are essential for colonisation and persistence in the gastric mucosa. The biochemistry and genetics of flagellar biogenesis in H. pylori has not been fully elucidated. Bioinformatics analysis suggested that the gene HP0256, annotated as hypothetical, was a FliJ homologue. In Salmonella, FliJ is a chaperone escort protein for FlgN and FliT, two proteins that themselves display chaperone activity for components of the hook, the rod and the filament. Results Ablation of the HP0256 gene in H. pylori significantly reduced motility. However, flagellin and hook protein synthesis was not affected in the HP0256 mutant. Transmission electron transmission microscopy revealed that the HP0256 mutant cells displayed a normal flagellum configuration, suggesting that HP0256 was not essential for assembly and polar localisation of the flagella in the cell. Interestingly, whole genome microarrays of an HP0256 mutant revealed transcriptional changes in a number of genes associated with the flagellar regulon and the cell envelope, such as outer membrane proteins and adhesins. Consistent with the array data, lack of the HP0256 gene significantly reduced adhesion and the inflammatory response in host cells. Conclusions We conclude that HP0256 is not a functional counterpart of FliJ in H. pylori. However, it is required for full motility and it is involved, possibly indirectly, in expression of outer membrane proteins and adhesins involved in pathogenesis and adhesion.

A single cysteine post-translational oxidation suffices to compromise globular proteins kinetic stability and promote amyloid formation

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Patrizia Marinelli

2018-04-01

Full Text Available Oxidatively modified forms of proteins accumulate during aging. Oxidized protein conformers might act as intermediates in the formation of amyloids in age-related disorders. However, it is not known whether this amyloidogenic conversion requires an extensive protein oxidative damage or it can be promoted just by a discrete, localized post-translational modification of certain residues. Here, we demonstrate that the irreversible oxidation of a single free Cys suffices to severely perturb the folding energy landscape of a stable globular protein, compromise its kinetic stability, and lead to the formation of amyloids under physiological conditions. Experiments and simulations converge to indicate that this specific oxidation-promoted protein aggregation requires only local unfolding. Indeed, a large scale analysis indicates that many cellular proteins are at risk of undergoing this kind of deleterious transition; explaining how oxidative stress can impact cell proteostasis and subsequently lead to the onset of pathological states. Keywords: Protein oxidation, Protein misfolding, Protein aggregation, Oxidative stress, Post-translational modification

Analysis of the human HP1 interactome reveals novel binding partners

DEFF Research Database (Denmark)

Rosnoblet, Claire; Vandamme, Julien; Völkel, Pamela

2011-01-01

Heterochromatin protein 1 (HP1) has first been described in Drosophila as an essential component of constitutive heterochromatin required for stable epigenetic gene silencing. Less is known about the three mammalian HP1 isotypes CBX1, CBX3 and CBX5. Here, we applied a tandem affinity purification...

Toward the description of electrostatic interactions between globular proteins: potential of mean force in the primitive model.

Science.gov (United States)

Dahirel, Vincent; Jardat, Marie; Dufrêche, Jean-François; Turq, Pierre

2007-09-07

Monte Carlo simulations are used to calculate the exact potential of mean force between charged globular proteins in aqueous solution. The aim of the present paper is to study the influence of the ions of the added salt on the effective interaction between these nanoparticles. The charges of the model proteins, either identical or opposite, are either central or distributed on a discrete pattern. Contrarily to Poisson-Boltzmann predictions, attractive, and repulsive direct forces between proteins are not screened similarly. Moreover, it has been shown that the relative orientations of the charge patterns strongly influence salt-mediated interactions. More precisely, for short distances between the proteins, ions enhance the difference of the effective forces between (i) like-charged and oppositely charged proteins, (ii) attractive and repulsive relative orientations of the proteins, which may affect the selectivity of protein/protein recognition. Finally, such results observed with the simplest models are applied to a more elaborate one to demonstrate their generality.

Globular clusters, old and young

International Nuclear Information System (INIS)

Samus', N.N.

1984-01-01

The problem of similarity of and difference in the globular and scattered star clusters is considered. Star clusters in astronomy are related either to globular or to scattered ones according to the structure of Hertzsprung-Russell diagram constructed for star clusters, but not according to the appearance. The qlobular clusters in the Galaxy are composed of giants and subgiants, which testifies to the old age of the globular clusters. The Globular clusters in the Magellanic clouds are classified into ''red'' ones - similar to the globular clusters of the Galaxy, and ''blue'' ones - similar to them in appearance but differing extremely by the star composition and so by the age. The old star clusters are suggested to be called globular ones, while another name (''populous'', for example) is suggested to be used for other clusters similar to globular ones only in appearance

Larger red-shift in optical emissions obtained from the thin films of globular proteins (BSA, lysozyme) – polyelectrolyte (PAA) complexes

Energy Technology Data Exchange (ETDEWEB)

Talukdar, Hrishikesh [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Kundu, Sarathi, E-mail: sarathi.kundu@gmail.com [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Basu, Saibal [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2016-09-30

Graphical abstract: Thin films of protein-polyelectrolyte complexes show larger red-shift in optical emission. - Highlights: • Globular proteins (lysozyme and BSA) and polyelectrolyte (sodium polyacrylic acid) are used to form protein-polyelectrolyte complexes (PPC). • Larger red-shift in optical emission is obtained from the thin films of PPC. • Red-shift is not obtained from the solution of PPC and pure protein thin films. • Larger red-shift from PPC films is due to the energy dissipation as non-radiative form through interactions with nearby atoms. • Red-shift in optical emission is independent on the thickness of the PPC film. - Abstract: Globular proteins (lysozyme and BSA) and polyelectrolyte (sodium polyacrylic acid) are used to form protein-polyelectrolyte complexes (PPC). Out-of-plane structures of ≈30–60 nm thick PPC films and their surface morphologies have been studied by using X-ray reflectivity and atomic force microscopy, whereas optical behaviors of PPC and protein conformations have been studied by using UV–vis, photoluminescence and FTIR spectroscopy respectively. Our study reveals that thin films of PPC show a larger red-shift of 23 and 16 nm in the optical emissions in comparison to that of pure protein whereas bulk PPC show a small blue-shift of ≈3 nm. A small amount of peak-shift is found to occur due to the heat treatment or concentration variation of the polyelectrolyte/protein in bulk solution but cannot produce such film thickness independent larger red-shift. Position of the emission peak remains nearly unchanged with the film thickness. Mechanism for such larger red-shift has been proposed.

Globular Clusters - Guides to Galaxies

CERN Document Server

Richtler, Tom; Joint ESO-FONDAP Workshop on Globular Clusters

2009-01-01

The principal question of whether and how globular clusters can contribute to a better understanding of galaxy formation and evolution is perhaps the main driving force behind the overall endeavour of studying globular cluster systems. Naturally, this splits up into many individual problems. The objective of the Joint ESO-FONDAP Workshop on Globular Clusters - Guides to Galaxies was to bring together researchers, both observational and theoretical, to present and discuss the most recent results. Topics covered in these proceedings are: internal dynamics of globular clusters and interaction with host galaxies (tidal tails, evolution of cluster masses), accretion of globular clusters, detailed descriptions of nearby cluster systems, ultracompact dwarfs, formations of massive clusters in mergers and elsewhere, the ACS Virgo survey, galaxy formation and globular clusters, dynamics and kinematics of globular cluster systems and dark matter-related problems. With its wide coverage of the topic, this book constitute...

Salt-bridge networks within globular and disordered proteins: characterizing trends for designable interactions.

Science.gov (United States)

Basu, Sankar; Mukharjee, Debasish

2017-07-01

There has been considerable debate about the contribution of salt bridges to the stabilization of protein folds, in spite of their participation in crucial protein functions. Salt bridges appear to contribute to the activity-stability trade-off within proteins by bringing high-entropy charged amino acids into close contacts during the course of their functions. The current study analyzes the modes of association of salt bridges (in terms of networks) within globular proteins and at protein-protein interfaces. While the most common and trivial type of salt bridge is the isolated salt bridge, bifurcated salt bridge appears to be a distinct salt-bridge motif having a special topology and geometry. Bifurcated salt bridges are found ubiquitously in proteins and interprotein complexes. Interesting and attractive examples presenting different modes of interaction are highlighted. Bifurcated salt bridges appear to function as molecular clips that are used to stitch together large surface contours at interacting protein interfaces. The present work also emphasizes the key role of salt-bridge-mediated interactions in the partial folding of proteins containing long stretches of disordered regions. Salt-bridge-mediated interactions seem to be pivotal to the promotion of "disorder-to-order" transitions in small disordered protein fragments and their stabilization upon binding. The results obtained in this work should help to guide efforts to elucidate the modus operandi of these partially disordered proteins, and to conceptualize how these proteins manage to maintain the required amount of disorder even in their bound forms. This work could also potentially facilitate explorations of geometrically specific designable salt bridges through the characterization of composite salt-bridge networks. Graphical abstract ᅟ.

Description of atomic burials in compact globular proteins by Fermi-Dirac probability distributions.

Science.gov (United States)

Gomes, Antonio L C; de Rezende, Júlia R; Pereira de Araújo, Antônio F; Shakhnovich, Eugene I

2007-02-01

We perform a statistical analysis of atomic distributions as a function of the distance R from the molecular geometrical center in a nonredundant set of compact globular proteins. The number of atoms increases quadratically for small R, indicating a constant average density inside the core, reaches a maximum at a size-dependent distance R(max), and falls rapidly for larger R. The empirical curves turn out to be consistent with the volume increase of spherical concentric solid shells and a Fermi-Dirac distribution in which the distance R plays the role of an effective atomic energy epsilon(R) = R. The effective chemical potential mu governing the distribution increases with the number of residues, reflecting the size of the protein globule, while the temperature parameter beta decreases. Interestingly, betamu is not as strongly dependent on protein size and appears to be tuned to maintain approximately half of the atoms in the high density interior and the other half in the exterior region of rapidly decreasing density. A normalized size-independent distribution was obtained for the atomic probability as a function of the reduced distance, r = R/R(g), where R(g) is the radius of gyration. The global normalized Fermi distribution, F(r), can be reasonably decomposed in Fermi-like subdistributions for different atomic types tau, F(tau)(r), with Sigma(tau)F(tau)(r) = F(r), which depend on two additional parameters mu(tau) and h(tau). The chemical potential mu(tau) affects a scaling prefactor and depends on the overall frequency of the corresponding atomic type, while the maximum position of the subdistribution is determined by h(tau), which appears in a type-dependent atomic effective energy, epsilon(tau)(r) = h(tau)r, and is strongly correlated to available hydrophobicity scales. Better adjustments are obtained when the effective energy is not assumed to be necessarily linear, or epsilon(tau)*(r) = h(tau)*r(alpha,), in which case a correlation with hydrophobicity

BtcA, A class IA type III chaperone, interacts with the BteA N-terminal domain through a globular/non-globular mechanism.

Directory of Open Access Journals (Sweden)

Chen Guttman

Full Text Available Bordetella pertussis, the etiological agent of "whooping cough" disease, utilizes the type III secretion system (T3SS to deliver a 69 kDa cytotoxic effector protein, BteA, directly into the host cells. As with other T3SS effectors, prior to its secretion BteA binds BtcA, a 13.9 kDa protein predicted to act as a T3SS class IA chaperone. While this interaction had been characterized for such effector-chaperone pairs in other pathogens, it has yet to be fully investigated in Bordetella. Here we provide the first biochemical proof that BtcA is indeed a class IA chaperone, responsible for the binding of BteA's N-terminal domain. We bring forth extensive evidence that BtcA binds its substrate effector through a dual-interface binding mechanism comprising of non-globular and bi-globular interactions at a moderate micromolar level binding affinity. We demonstrate that the non-globular interactions involve the first 31 N-terminal residues of BteA287 and their removal leads to destabilization of the effector-chaperone complex and lower binding affinities to BtcA. These findings represent an important first step towards a molecular understanding of BteA secretion and cell entry.

MeCP2 interacts with HP1 and modulates its heterochromatin association during myogenic differentiation

Science.gov (United States)

Agarwal, Noopur; Hardt, Tanja; Brero, Alessandro; Nowak, Danny; Rothbauer, Ulrich; Becker, Annette; Leonhardt, Heinrich; Cardoso, M. Cristina

2007-01-01

There is increasing evidence of crosstalk between epigenetic modifications such as histone and DNA methylation, recognized by HP1 and methyl CpG-binding proteins, respectively. We have previously shown that the level of methyl CpG-binding proteins increased dramatically during myogenesis leading to large-scale heterochromatin reorganization. In this work, we show that the level of HP1 isoforms did not change significantly throughout myogenic differentiation but their localization did. In particular, HP1γ relocalization to heterochromatin correlated with MeCP2 presence. Using co-immunoprecipitation assays, we found that these heterochromatic factors interact in vivo via the chromo shadow domain of HP1 and the first 55 amino acids of MeCP2. We propose that this dynamic interaction of HP1 and MeCP2 increases their concentration at heterochromatin linking two major gene silencing pathways to stabilize transcriptional repression during differentiation. PMID:17698499

Optics of globular photonic crystals

International Nuclear Information System (INIS)

Gorelik, V S

2007-01-01

The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ∼200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported. (review)

dAdd1 and dXNP prevent genome instability by maintaining HP1a localization at Drosophila telomeres.

Science.gov (United States)

Chavez, Joselyn; Murillo-Maldonado, Juan Manuel; Bahena, Vanessa; Cruz, Ana Karina; Castañeda-Sortibrán, América; Rodriguez-Arnaiz, Rosario; Zurita, Mario; Valadez-Graham, Viviana

2017-12-01

Telomeres are important contributors to genome stability, as they prevent linear chromosome end degradation and contribute to the avoidance of telomeric fusions. An important component of the telomeres is the heterochromatin protein 1a (HP1a). Mutations in Su(var)205, the gene encoding HP1a in Drosophila, result in telomeric fusions, retrotransposon regulation loss and larger telomeres, leading to chromosome instability. Previously, it was found that several proteins physically interact with HP1a, including dXNP and dAdd1 (orthologues to the mammalian ATRX gene). In this study, we found that mutations in the genes encoding the dXNP and dAdd1 proteins affect chromosome stability, causing chromosomal aberrations, including telomeric defects, similar to those observed in Su(var)205 mutants. In somatic cells, we observed that dXNP and dAdd1 participate in the silencing of the telomeric HTT array of retrotransposons, preventing anomalous retrotransposon transcription and integration. Furthermore, the lack of dAdd1 results in the loss of HP1a from the telomeric regions without affecting other chromosomal HP1a binding sites; mutations in dxnp also affected HP1a localization but not at all telomeres, suggesting a specialized role for dAdd1 and dXNP proteins in locating HP1a at the tips of the chromosomes. These results place dAdd1 as an essential regulator of HP1a localization and function in the telomere heterochromatic domain.

Operation of the HP2250 with the HP9000 series 200 using PASCAL 3.0

Science.gov (United States)

Perry, John; Stroud, C. W.

1986-01-01

A computer program has been written to provide an interface between the HP Series 200 desktop computers, operating under HP Standard Pascal 3.0, and the HP2250 Data Acquisition and Control System. Pascal 3.0 for the HP9000 desktop computer gives a number of procedures for handling bus communication at various levels. It is necessary, however, to reach the lowest possible level in Pascal to handle the bus protocols required by the HP2250. This makes programming extremely complex since these protocols are not documented. The program described solves those problems and allows the user to immediately program, simply and efficiently, any measurement and control language (MCL/50) application with a few procedure calls. The complete set of procedures is available on a 5 1/4 inch diskette from Cosmic. Included in this group of procedures is an Exerciser which allows the user to exercise his HP2250 interactively. The exerciser operates in a fashion similar to the Series 200 operating system programs, but is adapted to the requirements of the HP2250. The programs on the diskette and the user's manual assume the user is acquainted with both the MCL/50 programming language and HP Standard Pascal 3.0 for the HP series 200 desktop computers.

REVIEW: Optics of globular photonic crystals

Science.gov (United States)

Gorelik, V. S.

2007-05-01

The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ~200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported.

Relativistic Binaries in Globular Clusters

Directory of Open Access Journals (Sweden)

Matthew J. Benacquista

2013-03-01

Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

Comparison of the effects of weight loss from a high-protein versus standard-protein energy-restricted diet on strength and aerobic capacity in overweight and obese men.

Science.gov (United States)

Wycherley, Thomas P; Buckley, Jonathan D; Noakes, Manny; Clifton, Peter M; Brinkworth, Grant D

2013-02-01

To compare the effects of two low-fat, hypoenergetic diets differing in carbohydrate-to-protein ratio, on strength and aerobic capacity measures in overweight and obese men. In a parallel design, 56 men (age, 45.5 ± 8.7 years; BMI, 33.6 ± 3.9 kg/m(2)) were randomly assigned to a low-fat, energy-restricted diet (7,000 kJ/day) with either high protein (HP: protein/carbohydrate/fat % energy, 35:40:25) or standard protein (SP, 17:58:25). Body weight, body composition, muscle strength and aerobic capacity were assessed at baseline and after 12 weeks. Forty-two participants completed the study (HP, n = 21; SP, n = 21). Both groups experienced similar reductions in body weight (HP, -10.7 ± 5.3 kg [-9.8%]; SP, -8.7 ± 3.5 kg [-8.4%]) and fat-free mass (HP, -2.8 ± 3.6 kg; SP, -3.2 ± 2.7 kg; P 0.14 time × group interaction). There was a trend for a greater reduction in fat mass in the HP diet group, (-7.7 ± 4.3 kg [-21.2%] vs. -5.4 ± 3.3 kg [-15.1%]; P diet effect (P ≤ 0.23 time × group interaction). In overweight and obese men, both a HP and SP diet reduced body weight and improved body composition with similar effects on strength and aerobic capacity.

Photometric studies of globular clusters in the Andromeda Nebula. Luminosity function for old globular clusters

International Nuclear Information System (INIS)

Sharov, A.S.; Lyutyj, V.M.

1989-01-01

The luminosity function for old globular clusters in M 31 is presented. The objects were selected according to their structural and photometric properties. At the usually accepted normal (Gaussian) distribution, the luminosity function is characterized by the following parameters: the mean magnitude, corrected for the extinction inside M 31, V-bar 0 =16 m ,38±0 m .08, and the absolute magnitude M-bar v =-8 m .29 assuming )m-M) v =23 m .67, standard deviation σ M v =1 m .16±0 m .08 and total object number N=300±17. Old globular clusters in M 31 are in the average about one magnitude more luminous then those in our Galaxy (M v ≅ -7 m .3). Intrinsic luminosity dispersions of globular clusters are nearly the same in both galaxies. Available data on globular clusters in the Local Group galaxies against the universality of globular luminosity function with identical parameters M v and σ M v

Haptoglobin genotyping of Vietnamese: global distribution of HP del, complete deletion allele of the HP gene.

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Soejima, Mikiko; Agusa, Tetsuro; Iwata, Hisato; Fujihara, Junko; Kunito, Takashi; Takeshita, Haruo; Lan, Vi Thi Mai; Minh, Tu Binh; Takahashi, Shin; Trang, Pham Thi Kim; Viet, Pham Hung; Tanabe, Shinsuke; Koda, Yoshiro

2015-01-01

The haptoglobin (HP) gene deletion allele (HP(del)) is responsible for anhaptoglobinemia and a genetic risk factor for anaphylaxis reaction after transfusion due to production of the anti-HP antibody. The distribution of this allele has been explored by several groups including ours. Here, we studied the frequency of HP(del) in addition to the distribution of common HP genotypes in 293 Vietnamese. The HP(del) was encountered with the frequency of 0.020. The present result suggested that this deletion allele is restricted to East and Southeast Asians. Thus, this allele seems to be a potential ancestry informative marker for these populations. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

HP 9816

CERN Multimedia

1982-01-01

The 9816 was introduced in late 1982. This was the low-cost model in the 200 Series range. It only had two expansion slots and featured a monitor integrated with the system unit and modular keyboard and mass storage (usually a 9121 dual 3.5 inch floppy drive). The monitor was nine inches diagonally with a 400 by 300 dot resolution. The HP 9816 was also designated as the HP 9000 216. It did not include any disk drives but it had a built-in 9 inch monochrome monitor, built-in HP-IB and RS-232 ports and 2 expansion slots. The standard keyboard for the 9816 is a itty-bitty number. The 9816 A came with 128K bytes of memory. The 9816 S included all of the above plus disk based BASIC and a card containing an additional 256K of memory bringing the total memory to 512K but only leaving only one expansion slot open.

Identifying the adaptive mechanism in globular proteins: Fluctuations in densely packed regions manipulate flexible parts

Science.gov (United States)

Yilmaz, Lutfu Safak; Atilgan, Ali Rana

2000-09-01

A low-resolution structural model based on the packing geometry of α-carbons is utilized to establish a connection between the flexible and rigid parts of a folded protein. The former commonly recognizes a complementing molecule for making a complex, while the latter manipulates the necessary conformational change for binding. We attempt analytically to distinguish this control architecture that intrinsically exists in globular proteins. First with two-dimensional simple models, then for a native protein, bovine pancreatic trypsin inhibitor, we explicitly demonstrate that inserting fluctuations in tertiary contacts supported by the stable core, one can regulate the displacement of residues on loop regions. The positional fluctuations of the flexible regions are annihilated by the rest of the protein in conformity with the Le Chatelier-Braun principle. The results indicate that the distortion of the principal nonbonded contacts between highly packed residues is accompanied by that of the slavery fluctuations that are widely distributed over the native structure. These positional arrangements do not appear in a reciprocal relation between a perturbation and the associated response; the effect of a movement of residue i on residue j is not equal to that of the same movement of residue j on residue i.

Globular clusters and galaxy halos

International Nuclear Information System (INIS)

Van Den Bergh, S.

1984-01-01

Using semipartial correlation coefficients and bootstrap techniques, a study is made of the important features of globular clusters with respect to the total number of galaxy clusters and dependence of specific galaxy cluster on parent galaxy type, cluster radii, luminosity functions and cluster ellipticity. It is shown that the ellipticity of LMC clusters correlates significantly with cluster luminosity functions, but not with cluster age. The cluter luminosity value above which globulars are noticeably flattened may differ by a factor of about 100 from galaxy to galaxy. Both in the Galaxy and in M31 globulars with small core radii have a Gaussian distribution over luminosity, whereas clusters with large core radii do not. In the cluster systems surrounding the Galaxy, M31 and NGC 5128 the mean radii of globular clusters was found to increase with the distance from the nucleus. Central galaxies in rich clusters have much higher values for specific globular cluster frequency than do other cluster ellipticals, suggesting that such central galaxies must already have been different from normal ellipticals at the time they were formed

Prediction of extracellular proteases of the human pathogen Helicobacter pylori reveals proteolytic activity of the Hp1018/19 protein HtrA.

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Martin Löwer

Full Text Available Exported proteases of Helicobacter pylori (H. pylori are potentially involved in pathogen-associated disorders leading to gastric inflammation and neoplasia. By comprehensive sequence screening of the H. pylori proteome for predicted secreted proteases, we retrieved several candidate genes. We detected caseinolytic activities of several such proteases, which are released independently from the H. pylori type IV secretion system encoded by the cag pathogenicity island (cagPAI. Among these, we found the predicted serine protease HtrA (Hp1019, which was previously identified in the bacterial secretome of H. pylori. Importantly, we further found that the H. pylori genes hp1018 and hp1019 represent a single gene likely coding for an exported protein. Here, we directly verified proteolytic activity of HtrA in vitro and identified the HtrA protease in zymograms by mass spectrometry. Overexpressed and purified HtrA exhibited pronounced proteolytic activity, which is inactivated after mutation of Ser205 to alanine in the predicted active center of HtrA. These data demonstrate that H. pylori secretes HtrA as an active protease, which might represent a novel candidate target for therapeutic intervention strategies.

High-resolution mapping reveals links of HP1 with active and inactive chromatin components.

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Elzo de Wit

2007-03-01

Full Text Available Heterochromatin protein 1 (HP1 is commonly seen as a key factor of repressive heterochromatin, even though a few genes are known to require HP1-chromatin for their expression. To obtain insight into the targeting of HP1 and its interplay with other chromatin components, we have mapped HP1-binding sites on Chromosomes 2 and 4 in Drosophila Kc cells using high-density oligonucleotide arrays and the DNA adenine methyltransferase identification (DamID technique. The resulting high-resolution maps show that HP1 forms large domains in pericentric regions, but is targeted to single genes on chromosome arms. Intriguingly, HP1 shows a striking preference for exon-dense genes on chromosome arms. Furthermore, HP1 binds along entire transcription units, except for 5' regions. Comparison with expression data shows that most of these genes are actively transcribed. HP1 target genes are also marked by the histone variant H3.3 and dimethylated histone 3 lysine 4 (H3K4me2, which are both typical of active chromatin. Interestingly, H3.3 deposition, which is usually observed along entire transcription units, is limited to the 5' ends of HP1-bound genes. Thus, H3.3 and HP1 are mutually exclusive marks on active chromatin. Additionally, we observed that HP1-chromatin and Polycomb-chromatin are nonoverlapping, but often closely juxtaposed, suggesting an interplay between both types of chromatin. These results demonstrate that HP1-chromatin is transcriptionally active and has extensive links with several other chromatin components.

Virus-cell fusion inhibitory activity of novel analogue peptides based on the HP (2-20) derived from N-terminus of Helicobacter pylori Ribosomal Protein L1.

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Woo, Eun-Rhan; Lee, Dong Gun; Chang, Young-Su; Park, Yoonkyung; Hahm, Kyung-Soo

2002-12-01

HP (2-20) (AKKVFKRLEKLFSKIQNDK) is the antibacterial sequence derived from N-terminus of Helicobacter pylori Ribosomal Protein L1 (RPL1). It has a broad-spectrum microbicidal activity in vitro that is thought to be related to the membrane-disruptive properties of the peptide. Based on the putative membrane-targeted mode of action, we postulated that HP (2-20) might be possessed virus-cell fusion inhibitory activity. To develop the novel virus-cell fusion inhibitory peptides, several analogues with amino acid substitution were designed to increase or decrease only net hydrophobic region. In particular, substitution of Gln and Asp for hydrophobic amino acid, Trp at position 17 and 19 of HP (2-20) (Anal 3) caused a dramatic increase in virus-cell fusion inhibitory activity without hemolytic effect.

Front-face fluorescence spectroscopy study of globular proteins in emulsions: displacement of BSA by a nonionic surfactant.

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Rampon, V; Genot, C; Riaublanc, A; Anton, M; Axelos, M A V; McClements, D J

2003-04-23

The displacement of a globular protein (bovine serum albumin, BSA) from the surface of oil droplets in concentrated oil-in-water emulsions by a nonionic surfactant (polyoxyethylene sorbitan monolauarate, Tween 20) was studied using front-face fluorescence spectroscopy (FFFS). This method relies on measurement of the change in intensity (I(MAX)) and wavelength (lambda(MAX)) of the maximum in the tryptophan emission spectrum. A series of oil-in-water emulsions (21 wt % n-hexadecane, 0.22 wt % BSA, pH 7.0) containing different molar ratios of Tween 20 to BSA (R = 0-131) were prepared. As the surfactant concentration was increased, the protein was progressively displaced from the droplet surfaces. At R > or = 66, the protein was completely displaced from the droplet surfaces. There was an increase in both I(MAX) and lambda(MAX) with increasing Tween 20 concentration up to R = 66, which correlated with the increase in the ratio of nonadsorbed to adsorbed protein. In contrast, there was a decrease in I(MAX) and lambda(MAX) with Tween 20 concentration in protein solutions and for R > or = 66 in the emulsions, which was attributed to binding of the surfactant to the protein. This study shows that FFFS is a powerful technique for nondestructively providing information about the interfacial composition of droplets in concentrated protein-stabilized emulsions in situ. Nevertheless, in general the suitability of the technique may also depend on protein type and the nature of the physicochemical matrix surrounding the proteins.

Pregalactic formation of globular clusters in cold dark matter

International Nuclear Information System (INIS)

Faber, S.M.; Blumenthal, G.R.; Rosenblatt, E.I.

1988-01-01

The pregalactic hypothesis for the formation of globular clusters is reconsidered in the light of Zinn's (1985) discovery of a two-component globular population in the Milky Way. For a cold dark matter spectrum, high-sigma fluctuations of 10 to the 5th - 10 to the 6th solar masses are assumed to be the progenitors of the spheroidal population of globular clusters. The mass fraction of globular clusters in galaxies then requires that perturbations above roughly 2.8 sigma survive as globulars, and their observed radii require baryonic collapse factors of order 10. Such an absolute density threshold for globular cluster formation achieves adequate fits to observed cluster radii and densities, the mass fraction of globulars versus Hubble type, the radial density profile of globulars within galaxies, and the globular luminosity function. However, a fixed density threshold criterion for cluster survival lacks convincing physical justification and does not by itself explain the homogeneous metallicities within clusters or the large metallicity variations from cluster to cluster and from galaxy to galaxy. 33 references

75 FR 62424 - EDS, an HP Company (Re-Branded as HP-Enterprise Services) Including On-Site Workers From: Abel...

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2010-10-08

...-Branded as HP--Enterprise Services) Including On-Site Workers From: Abel Personnel Inc., Advantage Tech... February 4, 2010, applicable to workers of EDS, an HP Company (Re- branded as HP--Enterprise Services...-branded as HP-- Enterprise Services). These employees provided various activities related to the supply of...

Globular Clusters for Faint Galaxies

Science.gov (United States)

Kohler, Susanna

2017-07-01

The origin of ultra-diffuse galaxies (UDGs) has posed a long-standing mystery for astronomers. New observations of several of these faint giants with the Hubble Space Telescope are now lending support to one theory.Faint-Galaxy MysteryHubble images of Dragonfly 44 (top) and DFX1 (bottom). The right panels show the data with greater contrast and extended objects masked. [van Dokkum et al. 2017]UDGs large, extremely faint spheroidal objects were first discovered in the Virgo galaxy cluster roughly three decades ago. Modern telescope capabilities have resulted in many more discoveries of similar faint galaxies in recent years, suggesting that they are a much more common phenomenon than we originally thought.Despite the many observations, UDGs still pose a number of unanswered questions. Chief among them: what are UDGs? Why are these objects the size of normal galaxies, yet so dim? There are two primary models that explain UDGs:UDGs were originally small galaxies, hence their low luminosity. Tidal interactions then puffed them up to the large size we observe today.UDGs are effectively failed galaxies. They formed the same way as normal galaxies of their large size, but something truncated their star formation early, preventing them from gaining the brightness that we would expect for galaxies of their size.Now a team of scientists led by Pieter van Dokkum (Yale University) has made some intriguing observations with Hubble that lend weight to one of these models.Globulars observed in 16 Coma-cluster UDGs by Hubble. The top right panel shows the galaxy identifications. The top left panel shows the derived number of globular clusters in each galaxy. [van Dokkum et al. 2017]Globulars GaloreVan Dokkum and collaborators imaged two UDGs with Hubble: Dragonfly 44 and DFX1, both located in the Coma galaxy cluster. These faint galaxies are both smooth and elongated, with no obvious irregular features, spiral arms, star-forming regions, or other indications of tidal interactions

Chromosomal rearrangements and protein globularity changes in Mycobacterium tuberculosis isolates from cerebrospinal fluid

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Seow Hoon Saw

2016-09-01

Full Text Available Background Meningitis is a major cause of mortality in tuberculosis (TB. It is not clear what factors promote central nervous system invasion and pathology but it has been reported that certain strains of Mycobacterium tuberculosis (Mtb might have genetic traits associated with neurotropism. Methods In this study, we generated whole genome sequences of eight clinical strains of Mtb that were isolated from the cerebrospinal fluid (CSF of patients presenting with tuberculous meningitis (TBM in Malaysia, and compared them to the genomes of H37Rv and other respiratory Mtb genomes either downloaded from public databases or extracted from local sputum isolates. We aimed to find genomic features that might be distinctly different between CSF-derived and respiratory Mtb. Results Genome-wide comparisons revealed rearrangements (translocations, inversions, insertions and deletions and non-synonymous SNPs in our CSF-derived strains that were not observed in the respiratory Mtb genomes used for comparison. These rearranged segments were rich in genes for PE (proline-glutamate/PPE (proline-proline-glutamate, transcriptional and membrane proteins. Similarly, most of the ns SNPs common in CSF strains were noted in genes encoding PE/PPE proteins. Protein globularity differences were observed among mycobacteria from CSF and respiratory sources and in proteins previously reported to be associated with TB meningitis. Transcription factors and other transcription regulators featured prominently in these proteins. Homologs of proteins associated with Streptococcus pneumoniae meningitis and Neisseria meningitidis virulence were identified in neuropathogenic as well as respiratory mycobacterial spp. examined in this study. Discussion The occurrence of in silico genetic differences in CSF-derived but not respiratory Mtb suggests their possible involvement in the pathogenesis of TBM. However, overall findings in this comparative analysis support the postulation that TB

Growth promotion in pigs by oxytetracycline coincides with down regulation of serum inflammatory parameters and of hibernation-associated protein HP-27.

Science.gov (United States)

Soler, Laura; Miller, Ingrid; Hummel, Karin; Razzazi-Fazeli, Ebrahim; Jessen, Flemming; Escribano, Damian; Niewold, Theo

2016-05-01

The growth promoting effect of supplementing animal feed with antibiotics like tetracycline has traditionally been attributed to their antibiotic character. However, more evidence has been accumulated on their direct anti-inflammatory effect during the last two decades. Here we used a pig model to explore the systemic molecular effect of feed supplementation with sub therapeutic levels of oxytetracycline (OTC) by analysis of serum proteome changes. Results showed that OTC promoted growth, coinciding with a significant down regulation of different serum proteins related to inflammation, oxidation and lipid metabolism, confirming the anti-inflammatory mechanism of OTC. Interestingly, apart from the classic acute phase reactants also down regulation was seen of a hibernation associated plasma protein (HP-27), which is to our knowledge the first description in pigs. Although the exact function in non-hibernators is unclear, down regulation of HP-27 could be consistent with increased appetite, which is possibly linked to the anti-inflammatory action of OTC. Given that pigs are good models for human medicine due to their genetic and physiologic resemblance, the present results might also be used for rational intervention in human diseases in which inflammation plays an important role such as obesity, type 2 diabetes and cardiovascular diseases. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gamma-ray Emission from Globular Clusters

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Pak-Hin T. Tam

2016-03-01

Full Text Available Over the last few years, the data obtained using the Large Area Telescope (LAT aboard the Fermi Gamma-ray Space Telescope has provided new insights on high-energy processes in globular clusters, particularly those involving compact objects such as MilliSecond Pulsars (MSPs. Gamma-ray emission in the 100 MeV to 10 GeV range has been detected from more than a dozen globular clusters in our galaxy, including 47 Tucanae and Terzan 5. Based on a sample of known gammaray globular clusters, the empirical relations between gamma-ray luminosity and properties of globular clusters such as their stellar encounter rate, metallicity, and possible optical and infrared photon energy densities, have been derived. The measured gamma-ray spectra are generally described by a power law with a cut-off at a few gigaelectronvolts. Together with the detection of pulsed γ-rays from two MSPs in two different globular clusters, such spectral signature lends support to the hypothesis that γ-rays from globular clusters represent collective curvature emission from magnetospheres of MSPs in the clusters. Alternative models, involving Inverse-Compton (IC emission of relativistic electrons that are accelerated close to MSPs or pulsar wind nebula shocks, have also been suggested. Observations at >100 GeV by using Fermi/LAT and atmospheric Cherenkov telescopes such as H.E.S.S.-II, MAGIC-II, VERITAS, and CTA will help to settle some questions unanswered by current data.

The recombinant globular head domain of the measles virus hemagglutinin protein as a subunit vaccine against measles.

Science.gov (United States)

Lobanova, Liubov M; Eng, Nelson F; Satkunarajah, Malathy; Mutwiri, George K; Rini, James M; Zakhartchouk, Alexander N

2012-04-26

Despite the availability of live attenuated measles virus (MV) vaccines, a large number of measles-associated deaths occur among infants in developing countries. The development of a measles subunit vaccine may circumvent the limitations associated with the current live attenuated vaccines and eventually contribute to global measles eradication. Therefore, the goal of this study was to test the feasibility of producing the recombinant globular head domain of the MV hemagglutinin (H) protein by stably transfected human cells and to examine the ability of this recombinant protein to elicit MV-specific immune responses. The recombinant protein was purified from the culture supernatant of stably transfected HEK293T cells secreting a tagged version of the protein. Two subcutaneous immunizations with the purified recombinant protein alone resulted in the production of MV-specific serum IgG and neutralizing antibodies in mice. Formulation of the protein with adjuvants (polyphosphazene or alum) further enhanced the humoral immune response and in addition resulted in the induction of cell-mediated immunity as measured by the production of MV H-specific interferon gamma (IFN-γ) and interleukin 5 (IL-5) by in vitro re-stimulated splenocytes. Furthermore, the inclusion of polyphosphazene into the vaccine formulation induced a mixed Th1/Th2-type immune response. In addition, the purified recombinant protein retained its immunogenicity even after storage at 37°C for 2 weeks. Copyright © 2012 Elsevier Ltd. All rights reserved.

Predicting the activity coefficients of free-solvent for concentrated globular protein solutions using independently determined physical parameters.

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Devin W McBride

Full Text Available The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent model, which has previously been shown to provide excellent prediction of the osmotic pressure of concentrated and crowded globular proteins in aqueous solutions up to near-saturation concentrations. Thus, this model uses only the independently determined, physically realizable quantities: mole fraction, solvent accessible surface area, and ion binding, in its prediction. Predictions are presented for the activity coefficients of free-solvent for near-saturated protein solutions containing either bovine serum albumin or hemoglobin. As a verification step, the predictability of the model for the activity coefficient of sucrose solutions was evaluated. The predicted activity coefficients of free-solvent are compared to the calculated activity coefficients of free-solvent based on osmotic pressure data. It is observed that the predicted activity coefficients are increasingly dependent on the solute-solvent parameters as the protein concentration increases to near-saturation concentrations.

Helicobacter pylori HP1034 (ylxH) is required for motility

NARCIS (Netherlands)

van Amsterdam, Karin; van der Ende, Arie

2004-01-01

Background. Helicobacter pylori motility is essential for the colonization and persistence in the human gastric mucosa. So far, more than 50 genes have been described to play a role in flagellar biosynthesis. H. pylori YlxH (HP1034) is annotated as an ATP-binding protein. However, H. pylori YlxH

In Silico Characterization and Structural Modeling of Dermacentor andersoni p36 Immunosuppressive Protein

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Martin Omulindi Oyugi

2018-01-01

Full Text Available Ticks cause approximately $17–19 billion economic losses to the livestock industry globally. Development of recombinant antitick vaccine is greatly hindered by insufficient knowledge and understanding of proteins expressed by ticks. Ticks secrete immunosuppressant proteins that modulate the host’s immune system during blood feeding; these molecules could be a target for antivector vaccine development. Recombinant p36, a 36 kDa immunosuppressor from the saliva of female Dermacentor andersoni, suppresses T-lymphocytes proliferation in vitro. To identify potential unique structural and dynamic properties responsible for the immunosuppressive function of p36 proteins, this study utilized bioinformatic tool to characterize and model structure of D. andersoni p36 protein. Evaluation of p36 protein family as suitable vaccine antigens predicted a p36 homolog in Rhipicephalus appendiculatus, the tick vector of East Coast fever, with an antigenicity score of 0.7701 that compares well with that of Bm86 (0.7681, the protein antigen that constitute commercial tick vaccine Tickgard™. Ab initio modeling of the D. andersoni p36 protein yielded a 3D structure that predicted conserved antigenic region, which has potential of binding immunomodulating ligands including glycerol and lactose, found located within exposed loop, suggesting a likely role in immunosuppressive function of tick p36 proteins. Laboratory confirmation of these preliminary results is necessary in future studies.

THE SURFACE-MEDIATED UNFOLDING KINETICS OF GLOBULAR PROTEINS IS DEPENDENT ON MOLECULAR WEIGHT AND TEMPERATURE

Energy Technology Data Exchange (ETDEWEB)

Patananan, A.N.; Goheen, S.C.

2008-01-01

The adsorption and unfolding pathways of proteins on rigid surfaces are essential in numerous complex processes associated with biomedical engineering, nanotechnology, and chromatography. It is now well accepted that the kinetics of unfolding are characterized by chemical and physical interactions dependent on protein deformability and structure, as well as environmental pH, temperature, and surface chemistry. Although this fundamental process has broad implications in medicine and industry, little is known about the mechanism because of the atomic lengths and rapid time scales involved. Therefore, the unfolding kinetics of myoglobin, β-glucosidase, and ovalbumin were investigated by adsorbing the globular proteins to non-porous cationic polymer beads. The protein fractions were adsorbed at different residence times (0, 9, 10, 20, and 30 min) at near-physiological conditions using a gradient elution system similar to that in high-performance liquid chromatography. The elution profi les and retention times were obtained by ultraviolet/visible spectrophotometry. A decrease in recovery was observed with time for almost all proteins and was attributed to irreversible protein unfolding on the non-porous surfaces. These data, and those of previous studies, fi t a positively increasing linear trend between percent unfolding after a fi xed (9 min) residence time (71.8%, 31.1%, and 32.1% of myoglobin, β-glucosidase, and ovalbumin, respectively) and molecular weight. Of all the proteins examined so far, only myoglobin deviated from this trend with higher than predicted unfolding rates. Myoglobin also exhibited an increase in retention time over a wide temperature range (0°C and 55°C, 4.39 min and 5.74 min, respectively) whereas ovalbumin and β-glucosidase did not. Further studies using a larger set of proteins are required to better understand the physiological and physiochemical implications of protein unfolding kinetics. This study confi rms that surface

CVs and millisecond pulsar progenitors in globular clusters

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Grindlay, J. E.; Cool, A. M.; Bailyn, C. D.

1991-01-01

The recent discovery of a large population of millisecond pulsars in globular clusters, together with earlier studies of both low luminosity X-ray sources and LMXBs in globulars, suggest there should be significant numbers of CVs in globulars. Although they have been searched for without success in selected cluster X-ray source fields, systematic surveys are lacking and would constrain binary production and both stellar and dynamical evolution in globular clusters. We describe the beginnings of such a search, using narrow band H-alpha imaging, and the sensitivities it might achieve.

HP-SEE User Forum 2012

CERN Document Server

Karaivanova, Aneta; Oulas, Anastasis; Liabotis, Ioannis; Stojiljkovic, Danica; Prnjat, Ognjen

2014-01-01

This book is a collection of carefully reviewed papers presented during the HP-SEE User Forum, the meeting of the High-Performance Computing Infrastructure for South East Europe’s (HP-SEE) Research Communities, held in October 17-19, 2012, in Belgrade, Serbia. HP-SEE aims at supporting and integrating regional HPC infrastructures; implementing solutions for HPC in the region; and making HPC resources available to research communities in SEE, region, which are working in a number of scientific fields with specific needs for massively parallel execution on powerful computing resources. HP-SEE brings together research communities and HPC operators from 14 different countries and enables them to share HPC facilities, software, tools, data and research results, thus fostering collaboration and strengthening the regional and national human network; the project specifically supports research groups in the areas of computational physics, computational chemistry and the life sciences. The contributions presented i...

In silico studies of the properties of water hydrating a small protein

International Nuclear Information System (INIS)

Sinha, Sudipta Kumar; Chakraborty, Kausik; Bandyopadhyay, Sanjoy; Jana, Madhurima

2014-01-01

Atomistic molecular dynamics simulation of an aqueous solution of the small protein HP-36 has been carried out with explicit solvent at room temperature. Efforts have been made to explore the influence of the protein on the relative packing and ordering of water molecules around its secondary structures, namely, three α-helices. The calculations reveal that the inhomogeneous water ordering and density distributions around the helices are correlated with their relative hydrophobicity. Importantly, we have identified the existence of a narrow relatively dehydrated region containing randomly organized “quasi-free” water molecules beyond the first layer of “bound” waters at the protein surface. These water molecules with relatively weaker binding energies form the transition state separating the “bound” and “free” water molecules at the interface. Further, increased contribution of solid-like caging motions of water molecules around the protein is found to be responsible for reduced fluidity of the hydration layer. Interestingly, we notice that the hydration layer of helix-3 is more fluidic with relatively higher entropy as compared to the hydration layers of the other two helical segments. Such characteristics of helix-3 hydration layer correlate well with the activity of HP-36, as helix-3 contains the active site of the protein

In silico studies of the properties of water hydrating a small protein

Energy Technology Data Exchange (ETDEWEB)

Sinha, Sudipta Kumar; Chakraborty, Kausik; Bandyopadhyay, Sanjoy, E-mail: sanjoy@chem.iitkgp.ernet.in [Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur - 721302 (India); Jana, Madhurima [Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela - 769008 (India)

2014-12-14

Atomistic molecular dynamics simulation of an aqueous solution of the small protein HP-36 has been carried out with explicit solvent at room temperature. Efforts have been made to explore the influence of the protein on the relative packing and ordering of water molecules around its secondary structures, namely, three α-helices. The calculations reveal that the inhomogeneous water ordering and density distributions around the helices are correlated with their relative hydrophobicity. Importantly, we have identified the existence of a narrow relatively dehydrated region containing randomly organized “quasi-free” water molecules beyond the first layer of “bound” waters at the protein surface. These water molecules with relatively weaker binding energies form the transition state separating the “bound” and “free” water molecules at the interface. Further, increased contribution of solid-like caging motions of water molecules around the protein is found to be responsible for reduced fluidity of the hydration layer. Interestingly, we notice that the hydration layer of helix-3 is more fluidic with relatively higher entropy as compared to the hydration layers of the other two helical segments. Such characteristics of helix-3 hydration layer correlate well with the activity of HP-36, as helix-3 contains the active site of the protein.

KDM2A integrates DNA and histone modification signals through a CXXC/PHD module and direct interaction with HP1

Science.gov (United States)

Borgel, Julie; Tyl, Marek; Schiller, Karin; Pusztai, Zsofia; Dooley, Christopher M.; Deng, Wen; Wooding, Carol; White, Richard J.; Warnecke, Tobias; Leonhardt, Heinrich; Busch-Nentwich, Elisabeth M.

2017-01-01

Abstract Functional genomic elements are marked by characteristic DNA and histone modification signatures. How combinatorial chromatin modification states are recognized by epigenetic reader proteins and how this is linked to their biological function is largely unknown. Here we provide a detailed molecular analysis of chromatin recognition by the lysine demethylase KDM2A. Using biochemical approaches we identify a nucleosome interaction module within KDM2A consisting of a CXXC type zinc finger, a PHD domain and a newly identified Heterochromatin Protein 1 (HP1) interaction motif that mediates direct binding between KDM2A and HP1. This nucleosome interaction module enables KDM2A to decode nucleosomal H3K9me3 modification in addition to CpG methylation signals. The multivalent engagement with DNA and HP1 results in a nucleosome binding circuit in which KDM2A can be recruited to H3K9me3-modified chromatin through HP1, and HP1 can be recruited to unmodified chromatin by KDM2A. A KDM2A mutant deficient in HP1-binding is inactive in an in vivo overexpression assay in zebrafish embryos demonstrating that the HP1 interaction is essential for KDM2A function. Our results reveal a complex regulation of chromatin binding for both KDM2A and HP1 that is modulated by DNA- and H3K9-methylation, and suggest a direct role for KDM2A in chromatin silencing. PMID:28180290

Evaluation of HP0605 and HP0971 genes of efflux pumps in Helicobacter pylori resistance to Metronidazole

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Mohammad hasan Shirazi

2009-12-01

Full Text Available Background: The presence of antibiotic resistance has been reported in H.pylori and it is a major cause of treatment failure. Five families of multidrug efflux pumps are defined in bacteria and resistance-nodulation-division (RND pumps are found mainly in gram negative bacteria. TolC is one of RND pump components and play a critical role in drug resistance. It hasn’t been established that RND family has a role in drug resistance in H.pylori. In this study, we assessed the role of two efflux genes in resistant to metronidazole in H.pylori by evaluation of overexpression TolC genes by RT-PCR method. Methods: In five metronidazole resistant strains of H.pylori, total RNA was extracted. RNA treated with DNase and RNA reverse transcribed to cDNA. Aliquots of the cDNA solution were assayed by RT- PCR for HP0605 and HP0971 genes. The levels of mRNA expression were evaluated by densitometry analysis. Results: All five strains displayed overexpression for HP0605 basis of increased concentration of metronidazole. Three strains showed transcripts for HP0971. One of these had transcripts for HP0971 only in Metronidazole concentration equaled to 16 µg/ml but two strains overexpressed adapt to increase concentration of metronidazole. Conclusion: According to current study, HP0605 and HP0971 genes overexpressed due to increase metronidazole. So, increasing of Metronidazole affects in H.pylori΄s efflux system in transcription level.

Effect of protein solution components in the adsorption of Herbaspirillum seropedicae GlnB protein on mica.

Science.gov (United States)

Ferreira, Cecília F G; Benelli, Elaine M; Klein, Jorge J; Schreiner, Wido; Camargo, Paulo C

2009-10-15

The adsorption of proteins and its buffer solution on mica surfaces was investigated by atomic force microscopy (AFM). Different salt concentration of the Herbaspirillum seropedicae GlnB protein (GlnB-Hs) solution deposited on mica was investigated. This protein is a globular, soluble homotrimer (36kDa), member of PII-like proteins family involved in signal transducing in prokaryote. Supramolecular structures were formed when this protein was deposited onto bare mica surface. The topographic AFM images of the GlnB-Hs films showed that at high salt concentration the supramolecular structures are spherical-like, instead of the typical doughnut-like shape for low salt concentration. AFM images of NaCl and Tris from the buffer solution showed structures with the same pattern as those observed for high salt protein solution, misleading the image interpretation. XPS experiments showed that GlnB protein film covers the mica surface without chemical reaction.

Globular Clusters Shine in a Galaxy Lacking Dark Matter

Science.gov (United States)

Kohler, Susanna

2018-04-01

You may have seen recent news about NGC 1052DF2, a galaxy that was discovered to have little or no dark matter. Now, a new study explores what NGC 1052DF2 does have: an enigmatic population of unusually large and luminous globular clusters.Keck/LRIS spectra (left and right) and HST images (center) of the 11 clusters associated with NGC 1052DF2. The color images each span 1 1. [van Dokkum et al. 2018]An Unusual DwarfThe ultra-diffuse galaxy NGC 1052DF2, originally identified with the Dragonfly Telescope Array, has puzzled astronomers since the discovery that its dynamical mass determined by the motions of globular-cluster-like objects spotted within it is essentially the same as its stellar mass. This equivalence implies that the galaxy is strangely lacking dark matter; the upper limit set on its dark matter halo is 400 times smaller than what we would expect for such a dwarf galaxy.Led by Pieter van Dokkum (Yale University), the team that made this discovery has now followed up with detailed Hubble Space Telescope imaging and Keck spectroscopy. Their goal? To explore the objects that allowed them to make the dynamical-mass measurement: the oddly bright globular clusters of NGC 1052DF2.Sizes (circularized half-light radii) vs. absolute magnitudes for globular clusters in NGC1052DF2 (black) and the Milky Way (red). [Adapted from van Dokkum et al. 2018]Whats Up with the Globular Clusters?Van Dokkum and collaborators spectroscopically confirmed 11 compact objects associated with the faint galaxy. These objects are globular-cluster-like in their appearance, but the peak of their luminosity distribution is offset by a factor of four from globular clusters of other galaxies; these globular clusters are significantly brighter than is typical.Using the Hubble imaging, the authors determined that NGC 1052DF2s globular clusters are more than twice the size of the Milky Ways globular clusters in the same luminosity range. As is typical for globular clusters, they are an old

Biological assessment of neonicotinoids imidacloprid and its major metabolites for potentially human health using globular proteins as a model.

Science.gov (United States)

Ding, Fei; Peng, Wei

2015-06-01

The assessment of biological activities of imidacloprid and its two major metabolites, namely 6-chloronicotinic acid and 2-imidazolidone for nontarget organism, by employing essentially functional biomacromolecules, albumin and hemoglobin as a potentially model with the use of circular dichroism (CD), fluorescence, extrinsic 8-anilino-1-naphthalenesulfonic acid (ANS) fluorescence as well as molecular modeling is the theme of this work. By dint of CD spectra and synchronous fluorescence, it was clear that the orderly weak interactions between amino acid residues within globular proteins were disturbed by imidacloprid, and this event led to marginally alterations or self-regulations of protein conformation so as to lodge imidacloprid more tightly. Both steady state and time-resolved fluorescence suggested that the fluorescence of Trp residues in proteins was quenched after the presence of imidacloprid, corresponding to noncovalent protein-imidacloprid complexes formation and, the reaction belongs to moderate association (K=1.888/1.614×10(4)M(-1) for albumin/hemoglobin-imidacloprid, respectively), hydrogen bonds and π stacking performed a vital role in stabilizing the complexes, as derived from thermodynamic analysis and molecular modeling. With the aid of hydrophobic ANS experiments, subdomain IIA and α1β2 interface of albumin and hemoglobin, respectively, were found to be preserved high-affinity for imidacloprid. These results ties in with the subsequently molecular modeling laying imidacloprid in the Sudlow's site I and close to Trp-213 residue on albumin, while settling down B/Trp-37 residue nearby in hemoglobin, and these conclusions further confirmed by site-directed mutagenesis and molecular dynamics simulation. But, at the same time, several crucial noncovalent bonds came from other amino acid residues, e.g. Arg-194 and Arg-198 (albumin) and B/Arg-40, B/Asp-99 and B/Asn-102 (hemoglobin) cannot be ignored completely. Based on the comparative studies of

Chemical analysis of eight giant stars of the globular cluster NGC 6366

Science.gov (United States)

Puls, Arthur A.; Alves-Brito, Alan; Campos, Fabíola; Dias, Bruno; Barbuy, Beatriz

2018-05-01

The metal-rich Galactic globular cluster NGC 6366 is the fifth closest to the Sun. Despite its interest, it has received scarce attention, and little is known about its internal structure. Its kinematics suggests a link to the halo, but its metallicity indicates otherwise. We present a detailed chemical analysis of eight giant stars of NGC 6366, using high-resolution and high-quality spectra (R > 40 000, S/N > 60) obtained at the VLT (8.2 m) and CFHT (3.6 m) telescopes. We attempted to characterize its chemistry and to search for evidence of multiple stellar populations. The atmospheric parameters were derived using the method of excitation and ionization equilibrium of Fe I and Fe II lines and from those atmospheric parameters we calculated the abundances for other elements and found that none of the elements measured presents star-to-star variation greater than the uncertainties. We compared the derived abundances with those of other globular clusters and field stars available in the literature. We determined a mean [Fe/H] = -0.60 ± 0.03 for NGC 6366 and found some similarity of this object with M 71, another inner halo globular cluster. The Na-O anticorrelation extension is short and no star-to-star variation in Al is found. The presence of second generation stars is not evident in NGC 6366.

Mutation of charged residues to neutral ones accelerates urea denaturation of HP-35.

Science.gov (United States)

Wei, Haiyan; Yang, Lijiang; Gao, Yi Qin

2010-09-16

Following the studies of urea denaturation of β-hairpins using molecular dynamics, in this paper, molecular dynamics simulations of two peptides, a 35 residue three helix bundle villin headpiece protein HP-35 and its doubly norleucine-substituent mutant (Lys24Nle/Lys29Nle) HP-35 NleNle, were undertaken in urea solutions to understand the molecular mechanism of urea denaturation of α-helices. The mutant HP-35 NleNle was found to denature more easily than the wild type. During the expansion of the small hydrophobic core, water penetration occurs first, followed by that of urea molecules. It was also found that the initial hydration of the peptide backbone is achieved through water hydrogen bonding with the backbone CO groups during the denaturation of both polypeptides. The mutation of the two charged lysine residues to apolar norleucine enhances the accumulation of urea near the hydrophobic core and facilitates the denaturation process. Urea also interacts directly with the peptide backbone as well as side chains, thereby stabilizing nonnative conformations. The mechanism revealed here is consistent with the previous study on secondary structure of β-hairpin polypeptide, GB1, PEPTIDE 1, and TRPZIP4, suggesting that there is a general mechanism in the denaturation of protein backbone hydrogen bonds by urea.

HP investeerib tulevikku / Fredy-Edwin Esse

Index Scriptorium Estoniae

Esse, Fredy-Edwin

2010-01-01

Maailma suurima tehnoloogiafirma Hewlett-Packard (HP) tootearenduskulud kasvasid IV kvartalis 16%, 814 mln dollarini. Autor märgib, et HP aktsia on praegu väga hea saak, kuid mingit imehüpet aktsia hinnas ei tuleks kindlasti oodata

Reconstructing galaxy histories from globular clusters.

Science.gov (United States)

West, Michael J; Côté, Patrick; Marzke, Ronald O; Jordán, Andrés

2004-01-01

Nearly a century after the true nature of galaxies as distant 'island universes' was established, their origin and evolution remain great unsolved problems of modern astrophysics. One of the most promising ways to investigate galaxy formation is to study the ubiquitous globular star clusters that surround most galaxies. Globular clusters are compact groups of up to a few million stars. They generally formed early in the history of the Universe, but have survived the interactions and mergers that alter substantially their parent galaxies. Recent advances in our understanding of the globular cluster systems of the Milky Way and other galaxies point to a complex picture of galaxy genesis driven by cannibalism, collisions, bursts of star formation and other tumultuous events.

Nova-driven winds in globular clusters

International Nuclear Information System (INIS)

Scott, E.H.; Durisen, R.H.

1978-01-01

Recent sensitive searches for Hα emission from ionized intracluster gas in globular clusters have set upper limits that conflict with theoretical predictions. We suggest that nova outbursts heat the gas, producing winds that resolve this discrepancy. The incidence of novae in globular clusters, the conversion of kinetic energy of the nova shell to thermal energy of the intracluster gas, and the characteristics of the resultant winds are discussed. Calculated emission from the nova-driven models does not conflict with any observations to date. Some suggestions are made concerning the most promising approaches for future detection of intracluster gas on the basis of these models. The possible relationship of nova-driven winds of globular cluster X-ray sources is also considered

Identification and characterization of a nuclear localization signal of TRIM28 that overlaps with the HP1 box

International Nuclear Information System (INIS)

Moriyama, Tetsuji; Sangel, Percival; Yamaguchi, Hiroki; Obuse, Chikashi; Miyamoto, Yoichi; Oka, Masahiro; Yoneda, Yoshihiro

2015-01-01

Tripartite motif-containing 28 (TRIM28) is a transcription regulator, which forms a repressor complex containing heterochromatin protein 1 (HP1). Here, we report identification of a nuclear localization signal (NLS) within the 462-494 amino acid region of TRIM28 that overlaps with its HP1 binding site, HP1 box. GST-pulldown experiments revealed the interaction of the arginine-rich TRIM28 NLS with various importin α subtypes (α1, α2 and α4). In vitro transport assay demonstrated that nuclear localization of GFP-TRIM28 NLS is mediated by importin αs, in conjunction with importin β1 and Ran. Further, we demonstrated that HP1 and importin αs compete for binding to TRIM28. Together, our findings suggest that importin α has an essential role in the nuclear delivery and preferential HP1 interaction of TRIM28. - Highlights: • TRIM28 contains an NLS within the 462-494 amino acid region. • The nuclear import of TRIM28 is mediated by importin α/importin β1. • TRIM28 NLS overlaps with HP1 Box. • HP1 and importin α compete for binding to TRIM28

Identification and characterization of a nuclear localization signal of TRIM28 that overlaps with the HP1 box

Energy Technology Data Exchange (ETDEWEB)

Moriyama, Tetsuji; Sangel, Percival [Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085 (Japan); Yamaguchi, Hiroki [School of Medicine, Osaka University, Osaka 565-0871 (Japan); Obuse, Chikashi [Graduate School of Life Science, Hokkaido University, Sapporo 001-0021 (Japan); Miyamoto, Yoichi [Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085 (Japan); Oka, Masahiro, E-mail: moka@nibiohn.go.jp [Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085 (Japan); Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Yoneda, Yoshihiro, E-mail: y-yoneda@nibiohn.go.jp [National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085 (Japan); Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan)

2015-07-03

Tripartite motif-containing 28 (TRIM28) is a transcription regulator, which forms a repressor complex containing heterochromatin protein 1 (HP1). Here, we report identification of a nuclear localization signal (NLS) within the 462-494 amino acid region of TRIM28 that overlaps with its HP1 binding site, HP1 box. GST-pulldown experiments revealed the interaction of the arginine-rich TRIM28 NLS with various importin α subtypes (α1, α2 and α4). In vitro transport assay demonstrated that nuclear localization of GFP-TRIM28 NLS is mediated by importin αs, in conjunction with importin β1 and Ran. Further, we demonstrated that HP1 and importin αs compete for binding to TRIM28. Together, our findings suggest that importin α has an essential role in the nuclear delivery and preferential HP1 interaction of TRIM28. - Highlights: • TRIM28 contains an NLS within the 462-494 amino acid region. • The nuclear import of TRIM28 is mediated by importin α/importin β1. • TRIM28 NLS overlaps with HP1 Box. • HP1 and importin α compete for binding to TRIM28.

Shaping Globular Clusters with Black Holes

Science.gov (United States)

Kohler, Susanna

2018-03-01

How many black holes lurk within the dense environments of globular clusters, and how do these powerful objects shape the properties of the cluster around them? One such cluster, NGC 3201, is now helping us to answer these questions.Hunting Stellar-Mass Black HolesSince the detection of merging black-hole binaries by the Laser Interferometer Gravitational-Wave Observatory (LIGO), the dense environments of globular clusters have received increasing attention as potential birthplaces of these compact binary systems.The central region of the globular star cluster NGC 3201, as viewed by Hubble. The black hole is in orbit with the star marked by the blue circle. [NASA/ESA]In addition, more and more stellar-mass black-hole candidates have been observed within globular clusters, lurking in binary pairs with luminous, non-compact companions. The most recent of these detections, found in the globular cluster NGC 3201, stands alone as the first stellar-mass black hole candidate discovered via radial velocity observations: the black holes main-sequence companion gave away its presence via a telltale wobble.Now a team of scientists led by Kyle Kremer (CIERA and Northwestern University) is using models of this system to better understand the impact that black holes might have on their host clusters.A Model ClusterThe relationship between black holes and their host clusters is complicated. Though the cluster environment can determine the dynamical evolution of the black holes, the retention rate of black holes in a globular cluster (i.e., how many remain in the cluster when they are born as supernovae, rather than being kicked out during the explosion) influences how the host cluster evolves.Kremer and collaborators track this complex relationship by modeling the evolution of a cluster similar to NGC 3201 with a Monte Carlo code. The code incorporates physics relevant to the evolution of black holes and black-hole binaries in globular clusters, such as two-body relaxation

Tracing dust in old stellar populations : the mid-infrared spectrum of globular cluster AGB stars

International Nuclear Information System (INIS)

Richter, H.

2010-01-01

Asymptotic Giant Branch (AGB) stars are considered to be the main stellar dust producers in the universe. Their dusty circumstellar shells leave fingerprints in the mid-infrared (MIR) spectra of AGB stars and in unresolved old stellar populations. Bressan et al. (2007) showed that co-added MIR-spectra of AGB stars of known luminosity, metallicity and age (like those found in the Galactic globular cluster NGC104) can be used to model the dust excess in early-type galaxies. This work aims to improve our understanding of the MIR-spectra of old stellar populations with respect to their metallicities by studying a large sample of AGB stars in Galactic globular clusters. A sample of AGB stars (taken from Lebzelter et al. 2006 and Sloan et al. 2010) is used to produce co-added MIR-spectra of globular cluster combinations for three metallicity groups. Each group consists of several globular clusters with similar age and metallicity. Combining the clusters leads to a higher number of AGB stars with available Spitzer spectra in each group. The low metallicity group (Z=0.0038) consists of five globular clusters with 18 AGB star spectra, the intermediate (Z=0.0058) and high (Z=0.01) metallicity groups both include three clusters with eight and seven available MIR-spectra, respectively. Stars within the 90% mass radius of each globular cluster are used to generate 2MASS Color- Magnitude diagrams (CMDs) of each cluster combination. Binning the stars in the CMDs with respect to their MK-values results in Luminosity Functions (LFs) for the cluster combinations. The LFs based on 2MASS data are compared to LFs obtained using theoretical isochrones from the Padova group (Bertelli et al. 2008, Marigo et al. 2008). Using the 2MASS LFs integrated MIR-spectra of the three globular cluster combinations are derived by weighting the existing spectra with the total number of AGB stars within each MK-bin of the LFs along the upper giant branch. This relies on the assumption that stars that

Dinamical properties of globular clusters: Primordial or evolutional?

Science.gov (United States)

Surdin, V. G.

1995-04-01

Some observable relations between globular cluster parameters appear as a result of dynamical evolution of the cluster system. These relations are inapplicable to the studies of the globular cluster origin

GLOBULAR CLUSTERS AS CRADLES OF LIFE AND ADVANCED CIVILIZATIONS

Energy Technology Data Exchange (ETDEWEB)

Stefano, R. Di [Harvard-Smithsonian Center for Astrophysics (United States); Ray, A., E-mail: rdistefano@cfa.harvard.edu, E-mail: akr@tifr.res.in [Tata Institute of Fundamental Research (India)

2016-08-10

Globular clusters are ancient stellar populations in compact dense ellipsoids. There is no star formation and there are no core-collapse supernovae, but several lines of evidence suggest that globular clusters are rich in planets. If so, and if advanced civilizations can develop there, then the distances between these civilizations and other stars would be far smaller than typical distances between stars in the Galactic disk, facilitating interstellar communication and travel. The potent combination of long-term stability and high stellar densities provides a globular cluster opportunity. Yet the very proximity that promotes interstellar travel also brings danger, as stellar interactions can destroy planetary systems. We find, however, that large portions of many globular clusters are “sweet spots,” where habitable-zone planetary orbits are stable for long times. Globular clusters in our own and other galaxies are, therefore, among the best targets for searches for extraterrestrial intelligence (SETI). We use the Drake equation to compare the likelihood of advanced civilizations in globular clusters to that in the Galactic disk. We also consider free-floating planets, since wide-orbit planets can be ejected to travel through the cluster. Civilizations spawned in globular clusters may be able to establish self-sustaining outposts, reducing the probability that a single catastrophic event will destroy the civilization. Although individual civilizations may follow different evolutionary paths, or even be destroyed, the cluster may continue to host advanced civilizations once a small number have jumped across interstellar space. Civilizations residing in globular clusters could therefore, in a sense, be immortal.

GLOBULAR CLUSTERS AS CRADLES OF LIFE AND ADVANCED CIVILIZATIONS

International Nuclear Information System (INIS)

Stefano, R. Di; Ray, A.

2016-01-01

Globular clusters are ancient stellar populations in compact dense ellipsoids. There is no star formation and there are no core-collapse supernovae, but several lines of evidence suggest that globular clusters are rich in planets. If so, and if advanced civilizations can develop there, then the distances between these civilizations and other stars would be far smaller than typical distances between stars in the Galactic disk, facilitating interstellar communication and travel. The potent combination of long-term stability and high stellar densities provides a globular cluster opportunity. Yet the very proximity that promotes interstellar travel also brings danger, as stellar interactions can destroy planetary systems. We find, however, that large portions of many globular clusters are “sweet spots,” where habitable-zone planetary orbits are stable for long times. Globular clusters in our own and other galaxies are, therefore, among the best targets for searches for extraterrestrial intelligence (SETI). We use the Drake equation to compare the likelihood of advanced civilizations in globular clusters to that in the Galactic disk. We also consider free-floating planets, since wide-orbit planets can be ejected to travel through the cluster. Civilizations spawned in globular clusters may be able to establish self-sustaining outposts, reducing the probability that a single catastrophic event will destroy the civilization. Although individual civilizations may follow different evolutionary paths, or even be destroyed, the cluster may continue to host advanced civilizations once a small number have jumped across interstellar space. Civilizations residing in globular clusters could therefore, in a sense, be immortal.

Search for optical millisecond pulsars in globular clusters

International Nuclear Information System (INIS)

Middleditch, J.H.; Imamura, J.N.; Steiman-Cameron, T.Y.

1988-01-01

A search for millisecond optical pulsars in several bright, compact globular clusters was conducted. The sample included M28, and the X-ray clusters 47 Tuc, NGC 6441, NGC 6624, M22, and M15. The globular cluster M28 contains the recently discovered 327 Hz radio pulsar. Upper limits of 4 sigma to pulsed emission of (1-20) solar luminosities were found for the globular clusters tested, and 0.3 solar luminosity for the M28 pulsar for frequencies up to 500 Hz. 8 references

New VVV Survey Globular Cluster Candidates in the Milky Way Bulge

Energy Technology Data Exchange (ETDEWEB)

Minniti, Dante; Gómez, Matías [Departamento de Física, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. Fernandez Concha 700, Las Condes, Santiago (Chile); Geisler, Douglas; Fernández-Trincado, Jose G. [Departamento de Astronomía, Casilla 160-C, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Alonso-García, Javier; Beamín, Juan Carlos; Borissova, Jura; Catelan, Marcio; Ramos, Rodrigo Contreras; Kurtev, Radostin; Pullen, Joyce [Instituto Milenio de Astrofísica, Santiago (Chile); Palma, Tali; Clariá, Juan J. [Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, Córdoba (Argentina); Cohen, Roger E. [Space Telescope Science Institute, 2700 San Martin Drive, Baltimore (United States); Dias, Bruno [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Hempel, Maren [Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Av. Vicuña Mackenna 4860, Santiago (Chile); Ivanov, Valentin D. [European Southern Observatory, Karl-Schwarszchild-Str. 2, D-85748 Garching bei Muenchen (Germany); Lucas, Phillip W. [Dept. of Astronomy, University of Hertfordshire, Hertfordshire (United Kingdom); Moni-Bidin, Christian; Alegría, Sebastian Ramírez [Instituto de Astronomía, Universidad Católica del Norte, Antofagasta (Chile); and others

2017-11-10

It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major problems for finding globular clusters located toward the bulge. We use the deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey to search for globular clusters projected toward the Galactic bulge, and hereby report the discovery of 22 new candidate globular clusters. These objects, detected as high density regions in our maps of bulge red giants, are confirmed as globular cluster candidates by their color–magnitude diagrams. We provide their coordinates as well as their near-IR color–magnitude diagrams, from which some basic parameters are derived, such as reddenings and heliocentric distances. The color–magnitude diagrams reveal well defined red giant branches in all cases, often including a prominent red clump. The new globular cluster candidates exhibit a variety of extinctions (0.06 < A {sub Ks} < 2.77) and distances (5.3 < D < 9.5 kpc). We also classify the globular cluster candidates into 10 metal-poor and 12 metal-rich clusters, based on the comparison of their color–magnitude diagrams with those of known globular clusters also observed by the VVV Survey. Finally, we argue that the census for Galactic globular clusters still remains incomplete, and that many more candidate globular clusters (particularly the low luminosity ones) await to be found and studied in detail in the central regions of the Milky Way.

Silent decision: HP1 protein escorts heterochromatic RNAs to their destiny

Science.gov (United States)

Ren, Jie; Martienssen, Robert A

2012-01-01

EMBO J advance online publication 06072012; doi:10.1016/j.molcel.2012.05.009 Heterochromatin is classically perceived to be refractory to transcription because of its compact structure. However, Keller et al (2012) now demonstrated that heterochromatic transcripts can accumulate even when heterochromatin is normally packaged. By tracking down the fate of these heterochromatic RNAs, they revealed a new post-transcriptional mechanism of silencing in heterochromatin that involves the dynamic turnover of HP1Swi6 between its free, chromatin-bound and RNA-bound forms. The latter form escorts heterochromatic RNA to degradation. PMID:22705945

Photometric studies of globular clusters in the Andromeda nebula

International Nuclear Information System (INIS)

Sharov, A.S.; Lyutyj, V.M.

1983-01-01

The comparison of the frequency distribution of Bergh Q and Racine R metallicity parameters for globular clusters in the Galaxy and M31 is given. Mean values of the parameters are: in the Galaxy anti Q=-0.31 and anti R=0.40, in M31 anti Q=-0.32 and anti R=0.42. Hence the mean metallicity of globular clusters in two galaxies is identical. The differences in the observed frequency distribution of the parameters, in particular in the limits of general metallicity, are related to the random errors of photometrical measurements of globular clusters, considerably greater in the case of M31. Thereby the preference should be given to Hanes conclusion that globular clusters form a uniform population at least in two close systems. It should not be excepted that in other galaxies mean colour characteristics and hence metallicity of clusters may be of other type. Thus globular clusters related to the M31-NGC 205 satellite have somewhat minor B-V colour factors

TOWARDS THE CONCEPT OF GLOBULAR PEARLITE

OpenAIRE

A. G. Anisovich; M. K. Stepankova; A. A. Andrushevich

2016-01-01

Explanatory imprecisions of concept of globular pearlite and ferrite-carbide-mixture are considered. The need of concept binding of globular pearlite to specific grain with 0.8% carbon content is explained with the assistance of exemplary data obtained at the present metallographic equipment. The question of educational material presentation concerning the process of teaching of discipline «Materials and construction materials technology» is discussed in relation to the educational process of...

Helicobacter pylori antigen HP0986 (TieA) interacts with cultured gastric epithelial cells and induces IL8 secretion via NF-κB mediated pathway.

Science.gov (United States)

Devi, Savita; Ansari, Suhail A; Vadivelu, Jamuna; Mégraud, Francis; Tenguria, Shivendra; Ahmed, Niyaz

2014-02-01

The envisaged roles and partly understood functional properties of Helicobacter pylori protein HP0986 are significant in the context of proinflammatory and or proapoptotic activities, the two important facilitators of pathogen survival and persistence. In addition, sequence analysis of this gene predicts a restriction endonuclease function which remained unknown thus far. To evaluate the role of HP0986 in gastric inflammation, we studied its expression profile using a large number of clinical isolates but a limited number of biopsies and patient sera. Also, we studied antigenic role of HP0986 in altering cytokine responses of human gastric epithelial (AGS) cells including its interaction with and localization within the AGS cells. For in vitro expression study of HP0986, 110 H. pylori clinical isolates were cultured from patients with functional dyspepsia. For expression analysis by qRT PCR of HP0986, 10 gastric biopsy specimens were studied. HP0986 was also used to detect antibodies in patient sera. AGS cells were incubated with recombinant HP0986 to determine cytokine response and NF-κB activation. Transient transfection with HP0986 cloned in pEGFPN1 was used to study its subcellular localization or homing in AGS cells. Out of 110 cultured H. pylori strains, 34 (31%) were positive for HP0986 and this observation was correlated with in vitro expression profiles. HP0986 mRNA was detected in 7 of the 10 biopsy specimens. Further, HP0986 induced IL-8 secretion in gastric epithelial cells in a dose and time-dependent manner via NF-κB pathway. Serum antibodies against HP0986 were positively associated with H. pylori positive patients. Transient transfection of AGS cells revealed both cytoplasmic and nuclear localization of HP0986. HP0986 was moderately prevalent in clinical isolates and its expression profile in cultures and gastric biopsies points to its being naturally expressed. Collective observations including the induction of IL-8 via TNFR1 and NF

HP advances Grid Strategy for the adaptive enterprise

CERN Multimedia

2003-01-01

"HP today announced plans to further enable its enterprise infrastructure technologies for grid computing. By leveraging open grid standards, HP plans to help customers simplify the use and management of distributed IT resources. The initiative will integrate industry grid standards, including the Globus Toolkit and Open Grid Services Architecture (OGSA), across HP's enterprise product lines" (1 page).

Celiac disease and Hp infection association in Iran Enfermedades celiacas e infección por Hp en Irán

Directory of Open Access Journals (Sweden)

M. Rostami-Nejad

2009-12-01

Full Text Available Background: we assessed the prevalence, the related symptoms, and the endoscopic and histologic gastric features of celiac disease (CD in patients with Helicobacter pylori (Hp. Methods: 450 dyspeptic patients were studied. Biopsies of gastric antrum and duodenum, CD serology, and total IgA were obtained. Histological findings were scored with the Marsh-Rostami criteria. Results: 411 (91.3% patients were Hp positive. Duodenal histology was normal in 385 (85.6% patients, 124 (27.5% had duodenitis and 28 (6.2% showed duodenal abnormalities (Marsh I-IIIc. Twenty three/28 (82.1% patients with malabsorption pattern were also Hp positive. Serological analysis: 12 of 31 (38.7% positive patients had abnormal histology (Marsh I,-IIIc. Nine out 450 patients were IgA deficient; none of them was serologically positive for CD. Conclusion: although a high prevalence of Hp infection was found in this study, the relationship between Hp infection and CD was similar to that reported in other geographic areas.

The Aurora A-HP1γ pathway regulates gene expression and mitosis in cells from the sperm lineage.

Science.gov (United States)

Leonard, Phoebe H; Grzenda, Adrienne; Mathison, Angela; Morbeck, Dean E; Fredrickson, Jolene R; de Assuncao, Thiago M; Christensen, Trace; Salisbury, Jeffrey; Calvo, Ezequiel; Iovanna, Juan; Coddington, Charles C; Urrutia, Raul; Lomberk, Gwen

2015-05-29

HP1γ, a well-known regulator of gene expression, has been recently identified to be a target of Aurora A, a mitotic kinase which is important for both gametogenesis and embryogenesis. The purpose of this study was to define whether the Aurora A-HP1γ pathway supports cell division of gametes and/or early embryos, using western blot, immunofluorescence, immunohistochemistry, electron microscopy, shRNA-based knockdown, site-directed mutagenesis, and Affymetrix-based genome-wide expression profiles. We find that the form of HP1γ phosphorylated by Aurora A, P-Ser83 HP1γ, is a passenger protein, which localizes to the spermatozoa centriole and axoneme. In addition, disruption in this pathway causes centrosomal abnormalities and aberrations in cell division. Expression profiling of male germ cell lines demonstrates that HP1γ phosphorylation is critical for the regulation of mitosis-associated gene expression networks. In female gametes, we observe that P-Ser83-HP1γ is not present in meiotic centrosomes of M2 oocytes, but after syngamy, it becomes detectable during cleavage divisions, coinciding with early embryonic genome activation. These results support the idea that phosphorylation of HP1γ by Aurora A plays a role in the regulation of gene expression and mitotic cell division in cells from the sperm lineage and in early embryos. Combined, this data is relevant to better understanding the function of HP1γ in reproductive biology.

Protein scissors: Photocleavage of proteins at specific locations

Indian Academy of Sciences (India)

Unknown

Binding of ligands to globular proteins at hydrophobic cavities while making specific ... ched to a PTI model A1010 monochromator. UV cut-off filter ..... >1:1 stoichiometry (protein to ligand), the binding equilibrium favors the thermo- dynamically ...

BVRI main-sequence photometry of the globular cluster M4

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.

1984-01-01

We present BV and RI photographic photometry of 1421 and 189 stars, respectively, in the intermediate metallicity globular cluster M4 (NGC 6121). This investigation includes the first results of RI main-sequence photometry of a globular cluster. The use of longer wavelengths and longer color baselines provides the potential of improved isochrone fittings and underscores the urgent need for calculations of RI synthetic isochrones to be compared with observations. The Pickering-Racine wedge was used with the ESO 3.6 m telescope, the Las Campanas 2.5 m du Pont telescope, and the CTIO 1 m Yale telescope to extend the photoelectric limit from Vroughly-equal16.1 to Vroughly-equal19.1. We have determined the position of the main-sequence turnoff to lie at V = 16.6 +- 0.2 (m.e.) and B-V = 0.80 +- 0.03 (m.e.). A comparison of our BV observations with the CCD data of Richer and Fahlman shows excellent agreement: the two fifucial main sequences agree at all points to within 0.025 mag and, on average, to 0.013 mag. For the cluster we derive a distance modulus (m-M)/sub V/ = 12.52 +- 0.2 and reddening E(B-V) = 0.44 +- 0.03, results which confirm that at a distance of 2 kpc, M4 is the closest globular clusters to the Sun. Using the isochrones of VandenBerg, we deduce an age 13 +- 2 Gyr. As noted in several other investigations, there is a striking deficiency of stars in certain parts of the color-magnitude diagram; in M4 we find a pronounced gap over approx.0.6 mag at the base of the subgiant branch

Access to gram scale amounts of functional globular adiponectin from E. coli inclusion bodies by alkaline-shock solubilization.

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Heiker, John T; Klöting, Nora; Blüher, Matthias; Beck-Sickinger, Annette G

2010-07-16

The adipose tissue derived protein adiponectin exerts anti-diabetic, anti-inflammatory and anti-atherosclerotic effects. Adiponectin serum concentrations are in the microgram per milliliter range in healthy humans and inversely correlate with obesity and metabolic disorders. Accordingly, raising circulating adiponectin levels by direct administration may be an intriguing strategy in the treatment of obesity-related metabolic disorders. However production of large amounts of recombinant adiponectin protein is a primary obstacle so far. Here, we report a novel method for large amount production of globular adiponectin from E. coli inclusion bodies utilizing an alkaline-shock solubilization method without chaotropic agents followed by precipitation of the readily renaturing protein. Precipitation of the mildly solubilized protein capitalizes on advantages of inclusion body formation. This approach of inclusion body protein recovery provides access to gram scale amounts of globular adiponectin with standard laboratory equipment avoiding vast dilution or dialysis steps to neutralize the pH and renature the protein, thus saving chemicals and time. The precipitated protein is readily renaturing in buffer, is of adequate purity without a chromatography step and shows biological activity in cultured MCF7 cells and significantly lowered blood glucose levels in mice with streptozotocin induced type 1 diabetes. Copyright 2010 Elsevier Inc. All rights reserved.

TOWARDS THE CONCEPT OF GLOBULAR PEARLITE

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A. G. Anisovich

2016-01-01

Full Text Available Explanatory imprecisions of concept of globular pearlite and ferrite-carbide-mixture are considered. The need of concept binding of globular pearlite to specific grain with 0.8% carbon content is explained with the assistance of exemplary data obtained at the present metallographic equipment. The question of educational material presentation concerning the process of teaching of discipline «Materials and construction materials technology» is discussed in relation to the educational process of technical universities, in particular, the Belarusian State Agrarian Technical University.

Carbohydrate-restricted diets high in either monounsaturated fat or protein are equally effective at promoting fat loss and improving blood lipids.

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Luscombe-Marsh, Natalie D; Noakes, Manny; Wittert, Gary A; Keogh, Jennifer B; Foster, Paul; Clifton, Peter M

2005-04-01

When substituted for carbohydrate in an energy-reduced diet, dietary protein enhances fat loss in women. It is unknown whether the effect is due to increased protein or reduced carbohydrate. We compared the effects of 2 isocaloric diets that differed in protein and fat content on weight loss, lipids, appetite regulation, and energy expenditure after test meals. This was a parallel, randomized study in which subjects received either a low-fat, high-protein (LF-HP) diet (29 +/- 1% fat, 34 +/- 0.8% protein) or a high-fat, standard-protein (HF-SP) diet (45 +/- 0.6% fat, 18 +/- 0.3% protein) during 12 wk of energy restriction (6 +/- 0.1 MJ/d) and 4 wk of energy balance (7.4 +/- 0.3 MJ/d). Fifty-seven overweight and obese [mean body mass index (in kg/m(2)): 33.8 +/- 0.9] volunteers with insulin concentrations >12 mU/L completed the study. Weight loss (LF-HP group, 9.7 +/- 1.1 kg; HF-SP group, 10.2 +/- 1.4 kg; P = 0.78) and fat loss were not significantly different between diet groups even though the subjects desired less to eat after the LF-HP meal (P = 0.02). The decrease in resting energy expenditure was not significantly different between diet groups (LF-HP, -342 +/- 185 kJ/d; HF-SP, -349 +/- 220 kJ/d). The decrease in the thermic effect of feeding with weight loss was smaller in the LF-HP group than in the HF-SP group (-0.3 +/- 1.0% compared with -3.6 +/- 0.7%; P = 0.014). Glucose and insulin responses to test meals improved after weight loss (P loss and the improvements in insulin resistance and cardiovascular disease risk factors did not differ significantly between the 2 diets, and neither diet had any detrimental effects on bone turnover or renal function.

Species-Specific Monoclonal Antibodies to Escherichia coli-Expressed p36 Cytosolic Protein of Mycoplasma hyopneumoniae

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Caron, J.; Sawyer, N.; Moumen, B. Ben Abdel; Bouh, K. Cheikh Saad; Dea, S.

2000-01-01

The p36 protein of Mycoplasma hyopneumoniae is a cytosolic protein carrying species-specific antigenic determinants. Based on the genomic sequence of the reference strain ATCC 25934, primers were designed for PCR amplification of the p36-encoding gene (948 bp). These primers were shown to be specific to M. hyopneumoniae since no DNA amplicons could be obtained with other mycoplasma species and pathogenic bacteria that commonly colonize the porcine respiratory tract. The amplified p36 gene was subcloned into the pGEX-4T-1 vector to be expressed in Escherichia coli as a fusion protein with glutathione S-transferase (GST). The GST-p36 recombinant fusion protein was purified by affinity chromatography and cut by thrombin, and the enriched p36 protein was used to immunize female BALB/c mice for the production of anti-p36 monoclonal antibodies (MAbs). The polypeptide specificity of the nine MAbs obtained was confirmed by Western immunoblotting with cell lysates prepared from the homologous strain. Cross-reactivity studies of the anti-p36 MAbs towards two other M. hyopneumoniae reference strains (ATCC 25095 and J strains) and Quebec field strains that had been isolated in culture suggested that these anti-p36 MAbs were directed against a highly conserved epitope, or closely located epitopes, of the p36 protein. No reactivity was demonstrated against other mycoplasma species tested. Clinical signs and lesions suggestive of enzootic pneumonia were reproduced in specific-pathogen-free pigs infected experimentally with a virulent Quebec field strain (IAF-DM9827) of M. hyopneumoniae. The bacteria could be recovered from lung homogenates of pigs that were killed after the 3-week observation period by both PCR and cultivation procedures. Furthermore, the anti-p36 MAbs permitted effective detection by indirect immunofluorescence of M. hyopneumoniae in frozen lung sections from experimentally infected pigs. However, attempts to use the recombinant p36 protein as an antigen in an

RNA-binding proteins ZFP36L1 and ZFP36L2 promote cell quiescence.

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Galloway, Alison; Saveliev, Alexander; Łukasiak, Sebastian; Hodson, Daniel J; Bolland, Daniel; Balmanno, Kathryn; Ahlfors, Helena; Monzón-Casanova, Elisa; Mannurita, Sara Ciullini; Bell, Lewis S; Andrews, Simon; Díaz-Muñoz, Manuel D; Cook, Simon J; Corcoran, Anne; Turner, Martin

2016-04-22

Progression through the stages of lymphocyte development requires coordination of the cell cycle. Such coordination ensures genomic integrity while cells somatically rearrange their antigen receptor genes [in a process called variable-diversity-joining (VDJ) recombination] and, upon successful rearrangement, expands the pools of progenitor lymphocytes. Here we show that in developing B lymphocytes, the RNA-binding proteins (RBPs) ZFP36L1 and ZFP36L2 are critical for maintaining quiescence before precursor B cell receptor (pre-BCR) expression and for reestablishing quiescence after pre-BCR-induced expansion. These RBPs suppress an evolutionarily conserved posttranscriptional regulon consisting of messenger RNAs whose protein products cooperatively promote transition into the S phase of the cell cycle. This mechanism promotes VDJ recombination and effective selection of cells expressing immunoglobulin-μ at the pre-BCR checkpoint. Copyright © 2016, American Association for the Advancement of Science.

Implications of protein polymorphism on protein phase behaviour

NARCIS (Netherlands)

Stegen, J.; Schoot, van der P.P.A.M.

2015-01-01

The phase behaviour of small globular proteins is often modeled by approximating them as spherical particles with fixed internal structure. However, changes in the local environment of a protein can lead to changes in its conformation rendering this approximation invalid. We present a simple

Negative-tone imaging with EUV exposure for 14nm hp and beyond

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Tsubaki, Hideaki; Nihashi, Wataru; Tsuchihashi, Toru; Fujimori, Toru; Momota, Makoto; Goto, Takahiro

2015-03-01

Manipulation of dissolution properties by changing organic solvent developer and rinse material provides a novel technology to obtain fine pattern beyond the limitation of imaging system based on alkaline developer. QCM study showed no swelling character in negative-tone imaging (NTI) process even for current developer of n-butyl acetate (nBA). Actually, NTI process has shown advantages on resolution and line-width roughness (LWR) in loose pitch around 30 ~ 45 nm hp as a consequence of its non-swelling character. On the other hand, bridge and collapse limited its resolution below 20 nm hp, indicating that non-negligible amount of swelling still exists for tight pitch resolution. We investigated effects of solubility parameter of organic solvents on resolution below 20 nm hp. A bridge was reduced with a decrease in the solubility parameter dp from nBA. On the other hand, much lower dp caused film remaining due to its extremely slow Rmax. Based on these results, we newly developed FN-DP301 containing organic solvent with smaller dp than nBA. Although rinse solvent gave negligible effects on bridge, there is a clear improvement on pattern collapse only in case of using new rinse solvent of FN-RP311. Lithographic performances of NTI process using nBA and FN-DP301 together with the other organic solvents were described in this paper under exposures with an E-beam and a EUV light. It is emphasized that 14 nm hp resolution was obtained only using FN-DP301 as a developer and FN-RP311 as a rinse under E-beam exposure. NTI showed 43% faster photospeed in comparison with PTI at 16 nm hp, indicating that NTI is applicable to obtain high throughput with maintaining resolution. In addition, sub-20 nm trench was obtained using NTI without bridge under EUV exposure, all of which are attributed to the low swelling character of NTI process. Similarly, NTI was able to print 20 nm dots using NXE:3100 with only a little peeling. Conversely CH patterning was significantly worse with NTI

The immunomodulatory protein RH36 is relating to blood-feeding success and oviposition in hard ticks.

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Wang, Fangfang; Lu, Xiaojuan; Guo, Fengxun; Gong, Haiyan; Zhang, Houshuang; Zhou, Yongzhi; Cao, Jie; Zhou, Jinlin

2017-06-15

An immunomodulatory protein designated RH36 was identified in the tick Rhipicephalus haemaphysaloides. The cDNA sequence of RH36 has 844bp and encodes a deduced protein with a predicted molecular weight of 24kDa. Bioinformatics analysis indicated that RH36 presented a degree of similarity of 34.36% with the immunomodulatory protein p36 from the tick Dermacentor andersoni. The recombinant RH36 (rRH36) expressed in Sf9 insect cells suppressed the T-lymphocyte mitogen-driven in vitro proliferation of splenocytes and the expression of several cytokines such as IL-2, IL-12, and TNF-α. Furthermore, the proliferation of splenocytes isolated from rRH36-inoculated mice was significantly lower than that in control mice, suggesting that rRH36 could directly suppress immune responses in vivo. In addition, microarray analysis of splenocytes indicated that the expression of several immunomodulatory genes was downregulated by rRH36. The silencing of the RH36 gene by RNAi led to a 37.5% decrease in the tick attachment rate 24h after placement into the rabbit ears, whereas vaccination with RH36 caused a 53.06% decrease in the tick engorgement rate. Unexpectedly, RNAi induced a significant decrease in the oviposition rate, ovary weight at day 12 after engorgement, and egg-hatching rate. The effects of RH36 on blood feeding and oviposition were further confirmed by vaccination tests using the recombinant protein. These results indicate that RH36 is a novel member of immunosuppressant proteins and affects tick blood feeding and oviposition. Copyright © 2017 Elsevier B.V. All rights reserved.

Pulsar-irradiated stars in dense globular clusters

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Tavani, Marco

1992-01-01

We discuss the properties of stars irradiated by millisecond pulsars in 'hard' binaries of dense globular clusters. Irradiation by a relativistic pulsar wind as in the case of the eclipsing millisecond pulsar PSR 1957+20 alter both the magnitude and color of the companion star. Some of the blue stragglers (BSs) recently discovered in dense globular clusters can be irradiated stars in binaries containing powerful millisecond pulsars. The discovery of pulsar-driven orbital modulations of BS brightness and color with periods of a few hours together with evidence for radio and/or gamma-ray emission from BS binaries would valuably contribute to the understanding of the evolution of collapsed stars in globular clusters. Pulsar-driven optical modulation of cluster stars might be the only observable effect of a new class of binary pulsars, i.e., hidden millisecond pulsars enshrouded in the evaporated material lifted off from the irradiated companion star.

Possible systematic decreases in the age of globular clusters

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Shi, X. [Univ. of Chicago, Chicago, IL (United States); Schramm, D. N. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Univ. of Chicago, Chicago, IL (United States); Dearborn, D. S.P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Truran, J. W. [Univ. of Chicago, Chicago, IL (United States)

1994-03-01

The ages of globular clusters inferred from observations depends sensitively on assumptions like the initial helium abundance and the mass loss rate. A high helium abundance (e.g., Y\\approx0.28) or a mass loss rate of \\sim10^{-11}M_\\odot yr^{-1} near the main sequence turn-off region lowers the current age estimate from 14 Gyr to about 10--12 Gyr, significantly relaxing the constraints on the Hubble constant, allowing values as high as 60km/sec/Mpc for a universe with the critical density and 90km/sec/Mpc for a baryon-only universe. Possible mechanisms for the helium enhancement in globular clusters are discussed, as are arguments for an instability strip induced mass loss near the turn-off. Ages lower than 10 Gyr are not possible even with the operation of both of these mechanisms unless the initial helium abundance in globular clusters is >0.30, which would conflict with indirect measurements of helium abundances in globular clusters.

Meals based on vegetable protein sources (beans and peas are more satiating than meals based on animal protein sources (veal and pork – a randomized cross-over meal test study

Directory of Open Access Journals (Sweden)

Marlene D. Kristensen

2016-10-01

Full Text Available Background: Recent nutrition recommendations advocate a reduction in protein from animal sources (pork, beef because of environmental concerns. Instead, protein from vegetable sources (beans, peas should be increased. However, little is known about the effect of these vegetable protein sources on appetite regulation. Objective: To examine whether meals based on vegetable protein sources (beans/peas are comparable to meals based on animal protein sources (veal/pork regarding meal-induced appetite sensations. Design: In total, 43 healthy, normal-weight, young men completed this randomized, double-blind, placebo-controlled, three-way, cross-over meal test. The meals (all 3.5 MJ, 28 energy-% (E% fat were either high protein based on veal and pork meat, HP-Meat (19 E% protein, 53 E% carbohydrate, 6 g fiber/100 g; high protein based on legumes (beans and peas, HP-Legume (19 E% protein, 53 E% carbohydrate, 25 g fiber/100 g; or low-protein based on legumes, LP-Legume (9 E% protein, 62 E% carbohydrate, 10 g fiber/100 g. Subjective appetite sensations were recorded at baseline and every half hour using visual analog scales until the ad libitum meal 3 h after the test meal. Repeated measurements analyses and summary analyses were performed using ANCOVA (SAS. Results: HP-Legume induced lower composite appetite score, hunger, prospective food consumption, and higher fullness compared to HP-Meat and LP-Legume (p<0.05. Furthermore, satiety was higher after HP-Legume than HP-Meat (p<0.05. When adjusting for palatability, HP-Legume still resulted in lower composite appetite scores, hunger, prospective consumption, and higher fullness compared to HP-Meat (p<0.05. Furthermore, HP-Legume induced higher fullness than LP-Legume (p<0.05. A 12% and 13% lower energy intake, respectively, was seen after HP-Legume compared to HP-Meat or LP-Legume (p<0.01. Conclusion: Vegetable-based meals (beans/peas influenced appetite sensations favorably compared to animal-based meals

High-protein diets and renal status in rats

OpenAIRE

Aparicio, V. A.; Nebot, E.; García-del Moral, R.; Machado-Vílchez, M.; Porres, J. M.; Sánchez, C.; Aranda, P.

2013-01-01

Introduction: High-protein (HP) diets might affect renal status. We aimed to examine the effects of a HP diet on plasma, urinary and morphological renal parameters in rats. Material and methods: Twenty Wistar rats were randomly distributed in 2 experimental groups with HP or normal-protein (NP) diets over 12 weeks. Results and discussion: Final body weight was a 10% lower in the HP group (p < 0.05) whereas we have not observed differences on food intake, carcass weight and muscle ashes conten...

Chemical denaturation of globular proteins at the air/water interface: an x-ray and neutron reflectometry study

International Nuclear Information System (INIS)

Perriman, A.W.; Henderson, M.J.; White, J.W.

2003-01-01

Full text: X-ray and neutron reflectometry has been used to probe the equilibrium surface structure of hen egg white lysozyme (lysozyme) and bovine β -lactoglobulin (β -lactoglobulin) under denaturing conditions at the air-water interface. This was achieved by performing experiments on 10 mg mL -1 protein solutions containing increasing concentrations of the chemical denaturant guanidinium hydrochloride (G.HCl). For solutions containing no G.HCl, the surface structure of the proteins was represented by a two-layer model with total thicknesses of 48 Angstroms and 38 Angstroms for lysozyme and β -lactoglobulin, respectively. The total volume of a single protein molecule and the associated water molecules was evaluated to be approximately 45 (0.3) nm 3 for lysozyme, and 60 (0.3) nm 3 for β-lactoglobulin. The thickness dimensions and the total volumes compared favourably with the crystal dimensions of 45 x 30 x 30 Angstroms (40.5 nm 3 ),1 and 36 x 36 x 36 Angstroms (47 nm 3 ) 2 for lysozyme and β -lactoglobulin, respectively. This comparison suggests that when no denaturant was present, the structures of lysozyme and β -lactoglobulin were near to their native conformations at the air-water interface. The response to the presence of the chemical denaturant was different for each protein. The surface layer of β-lactoglobulin expanded at very low concentrations (0.2 mol dm -3 ) of G.HCl. In contrast, the lysozyme layer contracted. At higher concentrations, unfolding of both the proteins led to the formation of a third diffuse layer. In general, lysozyme appeared to be less responsive to the chemical denaturant, which is most likely a result of the higher disulfide content of lysozyme. A protocol allowing quantitative thermodynamic analysis of the contribution from the air-water interface to the chemical denaturation of a protein was developed

Comparative evaluation of electrostatic repulsion-hydrophilic interaction chromatography (ERLIC) and high-pH reversed phase (Hp-RP) chromatography in profiling of rat kidney proteome.

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Hao, Piliang; Ren, Yan; Dutta, Bamaprasad; Sze, Siu Kwan

2013-04-26

ERLIC and high-pH RP (Hp-RP) have been reported to be promising alternatives to strong cation exchange (SCX) in proteome fractionation. Here we compared the performance of ERLIC, concatenated ERLIC and concatenated Hp-RP in proteome profiling. The protein identification is comparable in these three strategies, but significantly more unique peptides are identified by the two concatenation methods, resulting in a significant increase of the average protein sequence coverage. The pooling of fractions from spaced intervals results in more uniform distribution of peptides in each fraction compared with the chromatogram-based pooling of adjacent fractions. ERLIC fractionates peptides according to their pI and GRAVY values. These properties remains but becomes less remarkable in concatenated ERLIC. In contrast, the average pI and GRAVY values of the peptides are comparable in each fraction in concatenated Hp-RP. ERLIC performs the best in identifying peptides with pI>9 among the three strategies, while concatenated Hp-RP is good at identifying peptides with pI<4. These advantages are useful when either basic or acidic peptides/proteins are analytical targets. The power of ERLIC in identification of basic peptides seems to be due to their efficient separation from acidic peptides. This study facilitates the choice of proper fractionation strategies based on specific objectives. For in-depth proteomic analysis of a cell, tissue and plasma, multidimensional liquid chromatography (MDLC) is still necessary to reduce sample complexity for improving analytical dynamic range and proteome coverage. This work conducts a direct comparison of three promising first-dimensional proteome fractionation methods. They are comparable in identifying proteins, but concatenated ERLIC and concatenated Hp-RP identify significantly more unique peptides than ERLIC. ERLIC is good at analyzing basic peptides, while concatenated Hp-RP performs the best in analyzing acidic peptides with pI<4. This

Effect of the horizontal branch on the colours of globular clusters

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Sil' chenko, O K [Moskovskij Gosudarstvennyj Univ. (USSR). Gosudarstvennyj Astronomicheskij Inst. ' ' GAISh' '

1963-05-01

The influence of the horizontal branch (HB) on the integral UBV colours of globular clusters is studied by means of statistical analysis of the colour-magnitude diagram catalogue for globular clusters of our Galaxy. The colour correction for HB is shown to be always negative. It turns out to be small for m. tal-rich globular clusters ((Fe/H)>-1.1) and independent on the HB shape for metal-poor ones.

Effect of the horizontal branch on the colours of globular clusters

International Nuclear Information System (INIS)

Sil'chenko, O.K.

1963-01-01

The influence of the horizontal branch (HB) on the integral UBV colours of globular clusters is studied by means of statistical analysis of the colour-magnitude diagram catalogue for globular clusters of our Galaxy. The colour correction for HB is shown to be always negative. It turns out to be small for m. tal-rich globular clusters ([Fe/H]>-1.1) and independent on the HB shape for metal-poor ones

The WAGGS project - I. The WiFeS Atlas of Galactic Globular cluster Spectra

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Usher, Christopher; Pastorello, Nicola; Bellstedt, Sabine; Alabi, Adebusola; Cerulo, Pierluigi; Chevalier, Leonie; Fraser-McKelvie, Amelia; Penny, Samantha; Foster, Caroline; McDermid, Richard M.; Schiavon, Ricardo P.; Villaume, Alexa

2017-07-01

We present the WiFeS Atlas of Galactic Globular cluster Spectra, a library of integrated spectra of Milky Way and Local Group globular clusters. We used the WiFeS integral field spectrograph on the Australian National University 2.3 m telescope to observe the central regions of 64 Milky Way globular clusters and 22 globular clusters hosted by the Milky Way's low-mass satellite galaxies. The spectra have wider wavelength coverage (3300-9050 Å) and higher spectral resolution (R = 6800) than existing spectral libraries of Milky Way globular clusters. By including Large and Small Magellanic Cloud star clusters, we extend the coverage of parameter space of existing libraries towards young and intermediate ages. While testing stellar population synthesis models and analysis techniques is the main aim of this library, the observations may also further our understanding of the stellar populations of Local Group globular clusters and make possible the direct comparison of extragalactic globular cluster integrated light observations with well-understood globular clusters in the Milky Way. The integrated spectra are publicly available via the project website.

Dynamic prestress in a globular protein.

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Scott A Edwards

Full Text Available A protein at equilibrium is commonly thought of as a fully relaxed structure, with the intra-molecular interactions showing fluctuations around their energy minimum. In contrast, here we find direct evidence for a protein as a molecular tensegrity structure, comprising a balance of tensed and compressed interactions, a concept that has been put forward for macroscopic structures. We quantified the distribution of inter-residue prestress in ubiquitin and immunoglobulin from all-atom molecular dynamics simulations. The network of highly fluctuating yet significant inter-residue forces in proteins is a consequence of the intrinsic frustration of a protein when sampling its rugged energy landscape. In beta sheets, this balance of forces is found to compress the intra-strand hydrogen bonds. We estimate that the observed magnitude of this pre-compression is enough to induce significant changes in the hydrogen bond lifetimes; thus, prestress, which can be as high as a few 100 pN, can be considered a key factor in determining the unfolding kinetics and pathway of proteins under force. Strong pre-tension in certain salt bridges on the other hand is connected to the thermodynamic stability of ubiquitin. Effective force profiles between some side-chains reveal the signature of multiple, distinct conformational states, and such static disorder could be one factor explaining the growing body of experiments revealing non-exponential unfolding kinetics of proteins. The design of prestress distributions in engineering proteins promises to be a new tool for tailoring the mechanical properties of made-to-order nanomaterials.

Millisecond radio pulsars in globular clusters

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Verbunt, Frank; Lewin, Walter H. G.; Van Paradijs, Jan

1989-01-01

It is shown that the number of millisecond radio pulsars, in globular clusters, should be larger than 100, applying the standard scenario that all the pulsars descend from low-mass X-ray binaries. Moreover, most of the pulsars are located in a small number of clusters. The prediction that Teran 5 and Liller 1 contain at least about a dozen millisecond radio pulsars each is made. The observations of millisecond radio pulsars in globular clusters to date, in particular the discovery of two millisecond radio pulsars in 47 Tuc, are in agreement with the standard scenario, in which the neutron star is spun up during the mass transfer phase.

Increasing protein intake modulates lipid metabolism in healthy young men and women consuming a high-fat hypercaloric diet.

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Rietman, Annemarie; Schwarz, Jessica; Blokker, Britt A; Siebelink, Els; Kok, Frans J; Afman, Lydia A; Tomé, Daniel; Mensink, Marco

2014-08-01

The objective of this study was to evaluate the effect of increasing protein intake, at the expense of carbohydrates, on intrahepatic lipids (IHLs), circulating triglycerides (TGs), and body composition in healthy humans consuming a high-fat, hypercaloric diet. A crossover randomized trial with a parallel control group was performed. After a 2-wk run-in period, participants were assigned to either the control diet [n = 10; 27.8 energy percent (en%) fat, 16.9 en% protein, 55.3 en% carbohydrates] for 4 wk or a high-fat, hypercaloric diet (n = 17; >2 MJ/d) crossover trial with 2 periods of 2 wk, with either high-protein (HP) (37.7 en% fat, 25.7 en% protein, 36.6 en% carbohydrates) or normal-protein (NP) (39.4 en% fat, 15.4 en% protein, 45.2 en% carbohydrates) content. Measurements were performed after 2 wk of run-in (baseline), 2 wk of intervention (period 1), and 4 wk of intervention (period 2). A trend toward lower IHL and plasma TG concentrations during the HP condition compared with the NP condition was observed (IHL: 0.35 ± 0.04% vs. 0.51 ± 0.08%, P = 0.08; TG: 0.65 ± 0.03 vs. 0.77 ± 0.05 mmol/L, P = 0.07, for HP and NP, respectively). Fat mass was significantly lower (10.6 ± 1.72 vs. 10.9 ± 1.73 kg; P = 0.02) with the HP diet than with the NP diet, whereas fat-free mass was higher (55.7 ± 2.79 vs. 55.2 ± 2.80 kg; P = 0.003). This study indicated that an HP, high-fat, hypercaloric diet affects lipid metabolism. It tends to lower the IHL and circulating TG concentrations and significantly lowers fat mass and increases fat-free mass compared with an NP, high-fat, hypercaloric diet. This trail was registered at www.clinicaltrials.gov as NCT01354626. © 2014 American Society for Nutrition.

Globular cluster metallicity scale: evidence from stellar models

International Nuclear Information System (INIS)

Demarque, P.; King, C.R.; Diaz, A.

1982-01-01

Theoretical giant branches have been constructed to determine their relative positions for metallicities in the range -2.3 0 )/sub 0,g/ based on these models is presented which yields good agreement over the observed range of metallicities for galactic globular clusters and old disk clusters. The metallicity of 47 Tuc and M71 given by this calibration is about -0.8 dex. Subject headings: clusters, globular: stars: abundances: stars: interiors

Comparison of high protein and high fiber weight-loss diets in women with risk factors for the metabolic syndrome: a randomized trial

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Williams Sheila M

2011-04-01

Full Text Available Abstract Background Studies have suggested that moderately high protein diets may be more appropriate than conventional low-fat high carbohydrate diets for individuals at risk of developing the metabolic syndrome and type 2 diabetes. However in most such studies sources of dietary carbohydrate may not have been appropriate and protein intakes may have been excessively high. Thus, in a proof-of-concept study we compared two relatively low-fat weight loss diets - one high in protein and the other high in fiber-rich, minimally processed cereals and legumes - to determine whether a relatively high protein diet has the potential to confer greater benefits. Methods Eighty-three overweight or obese women, 18-65 years, were randomized to either a moderately high protein (30% protein, 40% carbohydrate diet (HP or to a high fiber, relatively high carbohydrate (50% carbohydrate, > 35 g total dietary fiber, 20% protein diet (HFib for 8 weeks. Energy intakes were reduced by 2000 - 4000 kJ per day in order to achieve weight loss of between 0.5 and 1 kg per week. Results Participants on both diets lost weight (HP: -4.5 kg [95% confidence interval (CI:-3.7, -5.4 kg] and HFib: -3.3 kg [95% CI: -4.2, -2.4 kg], and reduced total body fat (HP: -4.0 kg [5% CI:-4.6, -3.4 kg] and HFib: -2.5 kg [95% CI: -3.5, -1.6 kg], and waist circumference (HP: -5.4 cm [95% CI: -6.3, -4.5 cm] and HFib: -4.7 cm [95% CI: -5.8, -3.6 cm], as well as total and LDL cholesterol, triglycerides, fasting plasma glucose and blood pressure. However participants on HP lost more body weight (-1.3 kg [95% CI: -2.5, -0.1 kg; p = 0.039] and total body fat (-1.3 kg [95% CI: -2.4, -0.1; p = 0.029]. Diastolic blood pressure decreased more on HP (-3.7 mm Hg [95% CI: -6.2, -1.1; p = 0.005]. Conclusions A realistic high protein weight-reducing diet was associated with greater fat loss and lower blood pressure when compared with a high carbohydrate, high fiber diet in high risk overweight and obese women.

Supra-galactic colour patterns in globular cluster systems

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Forte, Juan C.

2017-07-01

An analysis of globular cluster systems associated with galaxies included in the Virgo and Fornax Hubble Space Telescope-Advanced Camera Surveys reveals distinct (g - z) colour modulation patterns. These features appear on composite samples of globular clusters and, most evidently, in galaxies with absolute magnitudes Mg in the range from -20.2 to -19.2. These colour modulations are also detectable on some samples of globular clusters in the central galaxies NGC 1399 and NGC 4486 (and confirmed on data sets obtained with different instruments and photometric systems), as well as in other bright galaxies in these clusters. After discarding field contamination, photometric errors and statistical effects, we conclude that these supra-galactic colour patterns are real and reflect some previously unknown characteristic. These features suggest that the globular cluster formation process was not entirely stochastic but included a fraction of clusters that formed in a rather synchronized fashion over large spatial scales, and in a tentative time lapse of about 1.5 Gy at redshifts z between 2 and 4. We speculate that the putative mechanism leading to that synchronism may be associated with large scale feedback effects connected with violent star-forming events and/or with supermassive black holes.

Clinical value of 13C-UBT diagnosing infection of the Hp

International Nuclear Information System (INIS)

Xu Changde; Chen Shaoliang; Liu Wenguan

2004-01-01

100 dyspeptic patients are performed an endoscopy with biopsy for histology, rapid urease test, 13 C-urea breath test( 13 C-UBT) and ASSURE TM Hp rapid Test(HpRT). Patients are considered to be infected if both histology and biopsies yield positive results, and not infected when both tests are negative. The pathology and persons responsible for endoscopy, urease test and 13 C-UBT are unaware of the results from the other diagnostic methods. The 13 C-UBT has the following results: sensitivity 96% ,specificity 95%; rapid urease test has the following results: sensitivity 79%, specificity 76%; HpRT has the following results: sensitivity 86%, specificity 88%. 13 C-UBT provides excellent sensitivity and specificity for the diagnosis of Hp. Pylori infected Hp, it can be the first choice for detecting the infection of the Hp. (authors)

Images in the rocket ultraviolet - UV fluxes of M31 globular clusters

International Nuclear Information System (INIS)

Bohlin, R.C.; Cornett, R.H.; Hill, J.K.; Hill, R.S.; Stecher, T.P.

1988-01-01

Images obtained by a rocket-borne UV imaging telescope are used here to determine near-UV fluxes for 17 sources in M31 that are optical globular-cluster candidates and for the bright open cluster vdB0 in M31. Far-UV fluxes or flux limits are determined for the same clusters. The m(NUV)-V colors for M31 clusters are similar to those of Galactic clusters, except for the high-metallicity M31 cluster Bo 171. Four of the detected clusters have optical, m(NUV) - V, and m(FUV) - V colors indicating ages of about 100 million years. These four clusters are probably similar to the so-called 'blue globular' clusters of the LMC. The existence of young LMC-type blue globulars and the possible existence of middle-aged metal-rich globulars may indicate that M31 has continued to form globular clusters throughout its life. 39 references

Individual globular domains and domain unfolding visualized in overstretched titin molecules with atomic force microscopy.

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Zsolt Mártonfalvi

Full Text Available Titin is a giant elastomeric protein responsible for the generation of passive muscle force. Mechanical force unfolds titin's globular domains, but the exact structure of the overstretched titin molecule is not known. Here we analyzed, by using high-resolution atomic force microscopy, the structure of titin molecules overstretched with receding meniscus. The axial contour of the molecules was interrupted by topographical gaps with a mean width of 27.7 nm that corresponds well to the length of an unfolded globular (immunoglobulin and fibronectin domain. The wide gap-width distribution suggests, however, that additional mechanisms such as partial domain unfolding and the unfolding of neighboring domain multimers may also be present. In the folded regions we resolved globules with an average spacing of 5.9 nm, which is consistent with a titin chain composed globular domains with extended interdomain linker regions. Topographical analysis allowed us to allocate the most distal unfolded titin region to the kinase domain, suggesting that this domain systematically unfolds when the molecule is exposed to overstretching forces. The observations support the prediction that upon the action of stretching forces the N-terminal ß-sheet of the titin kinase unfolds, thus exposing the enzyme's ATP-binding site and hence contributing to the molecule's mechanosensory function.

Exploring the Internal Dynamics of Globular Clusters

Science.gov (United States)

Watkins, Laura L.; van der Marel, Roeland; Bellini, Andrea; Luetzgendorf, Nora; HSTPROMO Collaboration

2018-01-01

Exploring the Internal Dynamics of Globular ClustersThe formation histories and structural properties of globular clusters are imprinted on their internal dynamics. Energy equipartition results in velocity differences for stars of different mass, and leads to mass segregation, which results in different spatial distributions for stars of different mass. Intermediate-mass black holes significantly increase the velocity dispersions at the centres of clusters. By combining accurate measurements of their internal kinematics with state-of-the-art dynamical models, we can characterise both the velocity dispersion and mass profiles of clusters, tease apart the different effects, and understand how clusters may have formed and evolved.Using proper motions from the Hubble Space Telescope Proper Motion (HSTPROMO) Collaboration for a set of 22 Milky Way globular clusters, and our discrete dynamical modelling techniques designed to work with large, high-quality datasets, we are studying a variety of internal cluster properties. We will present the results of theoretical work on simulated clusters that demonstrates the efficacy of our approach, and preliminary results from application to real clusters.

Cocoa and Whey Protein Differentially Affect Markers of Lipid and Glucose Metabolism and Satiety.

Science.gov (United States)

Campbell, Caroline L; Foegeding, E Allen; Harris, G Keith

2016-03-01

Food formulation with bioactive ingredients is a potential strategy to promote satiety and weight management. Whey proteins are high in leucine and are shown to decrease hunger ratings and increase satiety hormone levels; cocoa polyphenolics moderate glucose levels and slow digestion. This study examined the effects of cocoa and whey proteins on lipid and glucose metabolism and satiety in vitro and in a clinical trial. In vitro, 3T3-L1 preadipocytes were treated with 0.5-100 μg/mL cocoa polyphenolic extract (CPE) and/or 1-15 mM leucine (Leu) and assayed for lipid accumulation and leptin production. In vivo, a 6-week clinical trial consisted of nine panelists (age: 22.6 ± 1.7; BMI: 22.3 ± 2.1) consuming chocolate-protein beverages once per week, including placebo, whey protein isolate (WPI), low polyphenolic cocoa (LP), high polyphenolic cocoa (HP), LP-WPI, and HP-WPI. Measurements included blood glucose and adiponectin levels, and hunger ratings at baseline and 0.5-4.0 h following beverage consumption. At levels of 50 and 100 μg/mL, CPE significantly inhibited preadipocyte lipid accumulation by 35% and 50%, respectively, and by 22% and 36% when combined with 15 mM Leu. Leu treatment increased adipocyte leptin production by 26-37%. In the clinical trial, all beverages significantly moderated blood glucose levels 30 min postconsumption. WPI beverages elicited lowest peak glucose levels and HP levels were significantly lower than LP. The WPI and HP beverage treatments significantly increased adiponectin levels, but elicited no significant changes in hunger ratings. These trends suggest that combinations of WPI and cocoa polyphenols may improve markers of metabolic syndrome and satiety.

DARK MATTER HALOS IN GALAXIES AND GLOBULAR CLUSTER POPULATIONS

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Hudson, Michael J.; Harris, Gretchen L. [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Harris, William E., E-mail: mjhudson@uwaterloo.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)

2014-05-20

We combine a new, comprehensive database for globular cluster populations in all types of galaxies with a new calibration of galaxy halo masses based entirely on weak lensing. Correlating these two sets of data, we find that the mass ratio η ≡ M {sub GCS}/M {sub h} (total mass in globular clusters, divided by halo mass) is essentially constant at (η) ∼ 4 × 10{sup –5}, strongly confirming earlier suggestions in the literature. Globular clusters are the only known stellar population that formed in essentially direct proportion to host galaxy halo mass. The intrinsic scatter in η appears to be at most 0.2 dex; we argue that some of this scatter is due to differing degrees of tidal stripping of the globular cluster systems between central and satellite galaxies. We suggest that this correlation can be understood if most globular clusters form at very early stages in galaxy evolution, largely avoiding the feedback processes that inhibited the bulk of field-star formation in their host galaxies. The actual mean value of η also suggests that about one-fourth of the initial gas mass present in protogalaxies collected into giant molecular clouds large enough to form massive, dense star clusters. Finally, our calibration of (η) indicates that the halo masses of the Milky Way and M31 are (1.2 ± 0.5) × 10{sup 12} M {sub ☉} and (3.9 ± 1.8) × 10{sup 12} M {sub ☉}, respectively.

RETENTION OF STELLAR-MASS BLACK HOLES IN GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Morscher, Meagan; Umbreit, Stefan; Farr, Will M.; Rasio, Frederic A.

2013-01-01

Globular clusters should be born with significant numbers of stellar-mass black holes (BHs). It has been thought for two decades that very few of these BHs could be retained through the cluster lifetime. With masses ∼10 M ☉ , BHs are ∼20 times more massive than an average cluster star. They segregate into the cluster core, where they may eventually decouple from the remainder of the cluster. The small-N core then evaporates on a short timescale. This is the so-called Spitzer instability. Here we present the results of a full dynamical simulation of a globular cluster containing many stellar-mass BHs with a realistic mass spectrum. Our Monte Carlo simulation code includes detailed treatments of all relevant stellar evolution and dynamical processes. Our main finding is that old globular clusters could still contain many BHs at present. In our simulation, we find no evidence for the Spitzer instability. Instead, most of the BHs remain well mixed with the rest of the cluster, with only the innermost few tens of BHs segregating significantly. Over the 12 Gyr evolution, fewer than half of the BHs are dynamically ejected through strong binary interactions in the cluster core. The presence of BHs leads to long-term heating of the cluster, ultimately producing a core radius on the high end of the distribution for Milky Way globular clusters (and those of other galaxies). A crude extrapolation from our model suggests that the BH-BH merger rate from globular clusters could be comparable to the rate in the field.

The anabolic response to a meal containing different amounts of protein is not limited by the maximal stimulation of protein synthesis in healthy young adults.

Science.gov (United States)

Kim, Il-Young; Schutzler, Scott; Schrader, Amy; Spencer, Horace J; Azhar, Gohar; Ferrando, Arny A; Wolfe, Robert R

2016-01-01

We have determined whole body protein kinetics, i.e., protein synthesis (PS), breakdown (PB), and net balance (NB) in human subjects in the fasted state and following ingestion of ~40 g [moderate protein (MP)], which has been reported to maximize the protein synthetic response or ~70 g [higher protein (HP)] protein, more representative of the amount of protein in the dinner of an average American diet. Twenty-three healthy young adults who had performed prior resistance exercise (X-MP or X-HP) or time-matched resting (R-MP or R-HP) were studied during a primed continuous infusion of l-[(2)H5]phenylalanine and l-[(2)H2]tyrosine. Subjects were randomly assigned into an exercise (X, n = 12) or resting (R, n = 11) group, and each group was studied at the two levels of dietary protein intake in random order. PS, PB, and NB were expressed as increases above the basal, fasting values (mg·kg lean body mass(-1)·min(-1)). Exercise did not significantly affect protein kinetics and blood chemistry. Feeding resulted in positive NB at both levels of protein intake: NB was greater in response to the meal containing HP vs. MP (P < 0.00001). The greater NB with HP was achieved primarily through a greater reduction in PB and to a lesser extent stimulation of protein synthesis (for all, P < 0.0001). HP resulted in greater plasma essential amino acid responses (P < 0.01) vs. MP, with no differences in insulin and glucose responses. In conclusion, whole body net protein balance improves with greater protein intake above that previously suggested to maximally stimulating muscle protein synthesis because of a simultaneous reduction in protein breakdown. Copyright © 2016 the American Physiological Society.

Infrared dust emission from globular clusters

International Nuclear Information System (INIS)

Angeletti, L.; Capuzzo-Dolcetta, R.; Giannone, P.; Blanco, A.; Bussoletti, E.

1982-01-01

The implications of the presence of a central cloud in the cores of globular clusters were investigated recently. A possible mechanism of confinement of dust in the central region of our cluster models was also explored. The grain temperature and infrared emission have now been computed for rather realistic grain compositions. The grain components were assumed to be graphite and/or silicates. The central clouds turned out to be roughly isothermal. The wavelengths of maximum emission came out to be larger than 20 μm in all studied cases. An application of the theoretical results to five globular clusters showed that the predictable infrared emission for 47 Tuc, M4 and M22 should be detectable by means of present instrumentation aboard flying platforms. (author)

Infrared dust emission from globular clusters

Energy Technology Data Exchange (ETDEWEB)

Angeletti, L; Capuzzo-Dolcetta, R; Giannone, P. (Rome Univ. (Italy). Osservatorio Astronomico); Blanco, A; Bussoletti, E [Lecce Univ. (Italy). Ist. di Fisica

1982-05-01

The implications of the presence of a central cloud in the cores of globular clusters were investigated recently. A possible mechanism of confinement of dust in the central region of our cluster models was also explored. The grain temperature and infrared emission have now been computed for rather realistic grain compositions. The grain components were assumed to be graphite and/or silicates. The central clouds turned out to be roughly isothermal. The wavelengths of maximum emission came out to be larger than 20 ..mu..m in all studied cases. An application of the theoretical results to five globular clusters showed that the predictable infrared emission for 47 Tuc, M4 and M22 should be detectable by means of present instrumentation aboard flying platforms.

Polymer collapse, protein folding, and the percolation threshold.

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Meirovitch, Hagai

2002-01-15

We study the transition of polymers in the dilute regime from a swollen shape at high temperatures to their low-temperature structures. The polymers are modeled by a single self-avoiding walk (SAW) on a lattice for which l of the monomers (the H monomers) are self-attracting, i.e., if two nonbonded H monomers become nearest neighbors on the lattice they gain energy of interaction (epsilon = -/epsilon/); the second type of monomers, denoted P, are neutral. This HP model was suggested by Lau and Dill (Macromolecules 1989, 22, 3986-3997) to study protein folding, where H and P are the hydrophobic and polar amino acid residues, respectively. The model is simulated on the square and simple cubic (SC) lattices using the scanning method. We show that the ground state and the sharpness of the transition depend on the lattice, the fraction g of the H monomers, as well as on their arrangement along the chain. In particular, if the H monomers are distributed at random and g is larger than the site percolation threshold of the lattice, a collapsed transition is very likely to occur. This conclusion, drawn for the lattice models, is also applicable to proteins where an effective lattice with coordination number between that of the SC lattice and the body centered cubic lattice is defined. Thus, the average fraction of hydrophobic amino acid residues in globular proteins is found to be close to the percolation threshold of the effective lattice.

Integrated photometry of globular star clusters in the Vilnius system

International Nuclear Information System (INIS)

Zdanavichyus, K.V.

1983-01-01

Integrated colour indices in the Vilnius photometric system and newly determined colour excesses Esub(B-V) for 39 globular clusters are presented. It is shown that the coincidence of integrated spectral types are not a sufficient criterion for the identity of intrinsic colour indices of globular clusters. Relation of integrated colour indices with the slope of the giant branch S and with the horizontal branch morphological type D is investigated. Integrated colour indices of clusters with a blue horizontal branch show no correlation with either D or S. The increase of colour indices of the clusters of types D >= 4 correlates with the distribution of stars along the horizontal branch. Integrated photometry of globular star clusters in the Vilnius multicoloured photometric system permits to determine their colour excesses from some Q diagrams and normal colour index. Integral normal colour indexes and Q parameters for I globular star clusters of the Mironov group display small changes as compared to clusters of group 2. Colour indexes among star clusters having only red horizontal branches (D=7) change most considerably

HP Ge planar detectors

International Nuclear Information System (INIS)

Gornov, M.G.; Gurov, Yu.B.; Soldatov, A.M.; Osipenko, B.P.; Yurkowski, J.; Podkopaev, O.I.

1989-01-01

Parameters of planar detectors manufactured of HP Ge are presented. The possibilities to use multilayer spectrometers on the base of such semiconductor detectors for nuclear physics experiments are discussed. It is shown that the obtained detectors including high square ones have spectrometrical characteristics close to limiting possible values. 9 refs.; 3 figs.; 1 tab

Near infrared photometry of globular clusters

International Nuclear Information System (INIS)

Evans, T.L.; Menzies, J.W.

1977-01-01

Photographic photometry on the V, Isub(K) system has been obtained for giant stars in the metal-rich globular clusters NGC 5927, 6171, 6352, 6356, 6388, 6522, 6528, 6712 and 6723. Colour-magnitude diagrams are presented. These data, with earlier observations of NGC 104 (47 Tuc), yield new parameters to describe the giant branch. These are the colour of the red variables, represented by their mean colour (V - Isub(K)) 0 or by the colour (V - Isub(K))sub(BO) of the bluest red variable on the giant branch of a cluster, and ΔV' which is the magnitude difference between the horizontal branch and the highest point on the giant branch. The latter is independent of reddening, since the giant branch of the most metal-rich clusters passes through a maximum in the V, V - Isub(K) plane. These parameters are correlated with the metal content, deduced from integrated photometry: the red variables are redder and the giant branch fainter the higher the metal content. Comparison with theoretical evolutionary tracks suggests that the range in metal content of these clusters is at most a factor of 10, the most metal-rich clusters possibly approaching the solar value. The cluster giant branches and those of open clusters, groups and field stars of the old disk population are compared. The assumption that all the globular clusters have an absolute magnitude on the horizontal branch of Msub(v) = + 0.9, as found recently for 47 Tuc, gives good agreement between the magnitudes of giant stars in the most metal rich of the globular clusters and those of field stars deduced from statistical parallaxes and moving group parallaxes. The values of the parameters ΔV' and (V - Isub(k))sub(BO) also approach those in the moving groups. The globular clusters have a longer horizontal branch, however, and the subgiants are bluer even when the values of ) 7Fe/H{ appear to be the same. (author). )

Increased Protein Consumption during the Day from an Energy-Restricted Diet Augments Satiety but Does Not Reduce Daily Fat or Carbohydrate Intake on a Free-Living Test Day in Overweight Women.

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Gwin, Jess A; Maki, Kevin C; Leidy, Heather J

2017-12-01

Background: Higher-protein (HP) energy-restriction diets improve weight management to a greater extent than normal-protein (NP) versions. Potential mechanisms of action with regard to assessment of eating behaviors across the day have not been widely examined during energy restriction. Objectives: The objectives of this study were to test whether the consumption of an HP energy-restriction diet reduces carbohydrate and fat intakes through improvements in daily appetite, satiety, and food cravings compared with NP versions and to test whether protein type within the NP diets alters protein-related satiety. Methods: Seventeen overweight women [mean ± SEM age: 36 ± 1 y; body mass index (kg/m 2 ): 28.4 ± 0.1] completed a randomized, controlled-feeding crossover study. Participants were provided with the following ∼1250-kcal/d energy-restricted (-750-kcal/d deficit) diets, each for 6 d: HP [124 g protein/d; 60% from beef and 40% from plant sources (HP-BEEF)] or NP (48 g protein/d) that was protein-type matched (NP-BEEF) or unmatched [100% from plant-based sources (NP-PLANT)]. On day 6 of each diet period, participants completed a 12-h testing day containing repetitive appetite, satiety, and food-craving questionnaires. On day 7, the participants were asked to consume their protein requirement within each respective diet but were provided with a surplus of carbohydrate- and fat-rich foods to consume, ad libitum, at each eating occasion across the day. All outcomes reported were primary study outcomes. Results: The HP-BEEF diet reduced daily hunger by 16%, desire to eat by 15%, prospective food consumption by 14%, and fast-food cravings by 15% but increased daily fullness by 25% compared with the NP-BEEF and NP-PLANT diets (all P protein throughout the day did not reduce the energy consumed ad libitum from the fat- and carbohydrate-rich foods (HP-BEEF: 2000 ± 180 kcal/d; NP-BEEF: 2120 ± 190 kcal/d; NP-PLANT: 2070 ± 180 kcal/d). None of the outcomes differed

The Effect of Replacing Fish Meal in the Diet with Enzyme-Treated Soybean Meal (HP310) on Growth and Body Composition of Rainbow Trout Fry.

Science.gov (United States)

Haghbayan, Samira; Shamsaie Mehrgan, Mehdi

2015-11-26

The potential of enzyme-treated soybean meal powder (HP310) as fish meal alternative in diets for rainbow trout weighing 1.17 ± 0.3 g was evaluated for 60 days. Fish meal was replaced with HP310 at 25%, 50%, 75% and 100% of experimental diets. A control group was also considered. The results showed that diets containing 75% and 100% HP310 had significantly higher feed conversion ratio and lower feed intake, weight gain and specific growth rate compared to fish feed diets containing higher levels of fish protein ingredients (p replacement levels of diet (p > 0.05). However increasing in level of HP310 in the diet caused a significant increase of the white blood cells (p replaced by HP310 showed the highest values of ash and moisture content among the diets and showed significantly different levels when compared with the control and other feeding treatments (p < 0.05).

On the evolution of globular clusters and the origin of galactic halo stars

International Nuclear Information System (INIS)

Surdin, V.G.

1978-01-01

Evolution of globular clusters of galactic halo is considered. It is shown that evolution of massive globular clusters with a greater degree of probability takes place under the effect of dynamic friction, which brings about the cluster fall on the center of galactic and their destruction by tidal forces. Evolution of small massive cluster takes place under the effect of dissipation. All the other reasons, causing the destruction of globular clusters (gravitational tidal forces, mutual cluster collision, outflow of gas from red gigant atmospheres, the change of the radius of the cluster orbit at the expense of the change of the galaxy mass inside the cluster orbit) play a secondary role. The whole mass of the stars lost by globular clusters does not exceed 10 7 M sun. It is concluded that the origin of the star population of galactic halo field can not be explained by destruction of already formed only astral globular clusters

Analytical Solution for Stellar Density in Globular Clusters MA Sharaf

Indian Academy of Sciences (India)

Introduction. A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. They are generally composed of hundreds of thousands of low-metal, old stars. The types of stars found in a globular cluster are similar to those in the bulge of a spiral galaxy but confined to a volume of only a few cubic ...

Effects of High vs. Low Protein Intake on Body Composition and Maximal Strength in Aspiring Female Physique Athletes Engaging in an 8-Week Resistance Training Program.

Science.gov (United States)

Campbell, Bill I; Aguilar, Danielle; Conlin, Laurin; Vargas, Andres; Schoenfeld, Brad Jon; Corson, Amey; Gai, Chris; Best, Shiva; Galvan, Elfego; Couvillion, Kaylee

2018-02-06

Aspiring female physique athletes are often encouraged to ingest relatively high levels of dietary protein in conjunction with their resistance-training programs. However, there is little to no research investigating higher vs. lower protein intakes in this population. This study examined the influence of a high vs. low protein diet in conjunction with an 8-week resistance training program in this population. Seventeen females (21.2±2.1 years; 165.1±5.1 cm; 61±6.1 kg) were randomly assigned to a high protein diet (HP: 2.5g/kg/day; n=8) or a low protein diet (LP: 0.9g/kg/day, n=9) and were assessed for body composition and maximal strength prior to and after the 8-week protein intake and exercise intervention. Fat-free mass (FFM) increased significantly more in the HP group as compared to the LP group (p=0.009), going from 47.1 ± 4.5kg to 49.2 ± 5.4kg (+2.1kg) and from 48.1 ± 2.7kg to 48.7 ± 2 (+0.6kg) in the HP and LP groups, respectively. Fat mass significantly decreased over time in the HP group (14.1 ± 3.6kg to 13.0 ± 3.3kg; p<0.01) but no change was observed in the LP group (13.2 ± 3.7kg to 12.5 ± 3.0kg). While maximal strength significantly increased in both groups, there were no differences in strength improvements between the two groups. In aspiring female physique athletes, a higher protein diet is superior to a lower protein diet in terms of increasing FFM in conjunction with a resistance training program.

DETAILED CHEMICAL ABUNDANCES OF FOUR STARS IN THE UNUSUAL GLOBULAR CLUSTER PALOMAR 1

International Nuclear Information System (INIS)

Sakari, Charli M.; Venn, Kim A.; Irwin, Mike; Aoki, Wako; Arimoto, Nobuo; Dotter, Aaron

2011-01-01

Detailed chemical abundances for 21 elements are presented for four red giants in the anomalous outer halo globular cluster Palomar 1 (R GC = 17.2 kpc, Z = 3.6 kpc) using high-resolution (R = 36, 000) spectra from the High Dispersion Spectrograph on the Subaru Telescope. Pal 1 has long been considered unusual because of its low surface brightness, sparse red giant branch, young age, and its possible association with two extragalactic streams of stars. This paper shows that its chemistry further confirms its unusual nature. The mean metallicity of the four stars, [Fe/H] = -0.60 ± 0.01, is high for a globular cluster so far from the Galactic center, but is low for a typical open cluster. The [α/Fe] ratios, though in agreement with the Galactic stars within the 1σ errors, agree best with the lower values in dwarf galaxies. No signs of the Na/O anticorrelation are detected in Pal 1, though Na appears to be marginally high in all four stars. Pal 1's neutron-capture elements are also unusual: its high [Ba/Y] ratio agrees best with dwarf galaxies, implying an excess of second-peak over first-peak s-process elements, while its [Eu/α] and [Ba/Eu] ratios show that Pal 1's contributions from the r-process must have differed in some way from normal Galactic stars. Therefore, Pal 1 is unusual chemically, as well in its other properties. Pal 1 shares some of its unusual abundance characteristics with the young clusters associated with the Sagittarius dwarf galaxy remnant and the intermediate-age LMC clusters, and could be chemically associated with the Canis Majoris overdensity; however, it does not seem to be similar to the Monoceros/Galactic Anticenter Stellar Stream.

Predicting protein folding rate change upon point mutation using residue-level coevolutionary information.

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Mallik, Saurav; Das, Smita; Kundu, Sudip

2016-01-01

Change in folding kinetics of globular proteins upon point mutation is crucial to a wide spectrum of biological research, such as protein misfolding, toxicity, and aggregations. Here we seek to address whether residue-level coevolutionary information of globular proteins can be informative to folding rate changes upon point mutations. Generating residue-level coevolutionary networks of globular proteins, we analyze three parameters: relative coevolution order (rCEO), network density (ND), and characteristic path length (CPL). A point mutation is considered to be equivalent to a node deletion of this network and respective percentage changes in rCEO, ND, CPL are found linearly correlated (0.84, 0.73, and -0.61, respectively) with experimental folding rate changes. The three parameters predict the folding rate change upon a point mutation with 0.031, 0.045, and 0.059 standard errors, respectively. © 2015 Wiley Periodicals, Inc.

A New Globular Cluster in the Area of VVVX

Science.gov (United States)

Bica, E.; Minniti, D.; Bonatto, C.; Hempel, M.

2018-06-01

We communicate the discovery of a new globular cluster in the Galaxy that was first detected on WISE/2MASS images and is now confirmed with VVVX photometry. It is a Palomar-like cluster projected at ℓ = 359.15°, b = 5.73°, and may be related to the bulge. We derive an absolute magnitude of MV ≈ -3.3, thus being an underluminous globular cluster. Our analyses provide a reddening of E(B - V) = 1.08 ± 0.18 and a distance to the Sun d⊙ = 6.3 ± 1 kpc, which implies a current position in the bulge volume. The estimated metallicity is [Fe/H] = -1.5 ± 0.25. It adds to the recently discovered faint globular cluster (Minniti 22) and candidates found with VVV, building up expectations of ≈50 globular clusters yet to be discovered in the bulge. We also communicate the discovery of an old open cluster in the same VVVX tile as the globular cluster. The VVVX photometry provided E(B - V) = 0.62 ± 0.1, d⊙ = 7.6 ± 1 kpc, and an age of 1.5 ± 0.3 Gyr. With a height from the plane of ≈0.8 kpc, it adds to nine Gyr-class clusters recently discovered within 0.8 ⩽ Z ⩽ 2.2 kpc, as recently probed in the single VVV tile b201. We suggest that these findings may be disclosing the thick disk at the bulge, which so far has no open cluster counterpart, and hardly any individual star. Thus, the VVV and VVVX surveys are opening new windows for follow-up studies, to employ present and future generations of large aperture telescopes.

Systematic main sequence photometry of globular cluster stars for age determination

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.

1984-01-01

The individual photometric study of the coeval stars in globular clusters presents one of the best observational tests of the stellar evolution theory. Our own globular cluster system provides fundamental clues to the dynamical and chemical evolutionary history of the galaxy, and the study of their ages give a lower limit to the age of the galaxy as well as to that of the universe. The authors have undertaken a systematic research program, and discuss the ages deduced by fitting main sequence photometry to theoretical isochrones of six galactic globular clusters: M4, M22, M30, NGC 288, NGC 3201 and NGC 6397. (Auth.)

EVIDENCE FOR AN ACCRETION ORIGIN FOR THE OUTER HALO GLOBULAR CLUSTER SYSTEM OF M31

International Nuclear Information System (INIS)

Mackey, A. D.; Huxor, A. P.; Ferguson, A. M. N.; Irwin, M. J.; Chapman, S. C.; Tanvir, N. R.; McConnachie, A. W.; Ibata, R. A.; Lewis, G. F.

2010-01-01

We use a sample of newly discovered globular clusters from the Pan-Andromeda Archaeological Survey (PAndAS) in combination with previously cataloged objects to map the spatial distribution of globular clusters in the M31 halo. At projected radii beyond ∼30 kpc, where large coherent stellar streams are readily distinguished in the field, there is a striking correlation between these features and the positions of the globular clusters. Adopting a simple Monte Carlo approach, we test the significance of this association by computing the probability that it could be due to the chance alignment of globular clusters smoothly distributed in the M31 halo. We find that the likelihood of this possibility is low, below 1%, and conclude that the observed spatial coincidence between globular clusters and multiple tidal debris streams in the outer halo of M31 reflects a genuine physical association. Our results imply that the majority of the remote globular cluster system of M31 has been assembled as a consequence of the accretion of cluster-bearing satellite galaxies. This constitutes the most direct evidence to date that the outer halo globular cluster populations in some galaxies are largely accreted.

The central globular domain of the nucleocapsid protein of human immunodeficiency virus type 1 is critical for virion structure and infectivity.

Science.gov (United States)

Ottmann, M; Gabus, C; Darlix, J L

1995-03-01

The nucleocapsid protein NCp7 of human immunodeficiency virus type 1 (HIV-1) is a 72-amino-acid peptide containing two CCHC-type zinc fingers linked by a short basic sequence, 29RAPRKKG35, which is conserved in HIV-1 and simian immunodeficiency virus. The complete three-dimensional structure of NCp7 has been determined by 1H-nuclear magnetic resonance spectroscopy (N. Morellet, H. de Rocquigny, Y. Mely, N. Jullian, H. Demene, M. Ottmann, D. Gerard, J. L. Darlix, M. C. Fournié-Zaluski, and B. P. Roques, J. Mol. Biol. 235:287-301, 1994) and revealed a central globular domain where the two zinc fingers are brought in close proximity by the RAPRKKG linker. To examine the role of this globular structure and more precisely of the RAPRKKG linker in virion structure and infectivity, we generated HIV-1 DNA mutants in the RAPRKK sequence of NCp7 and analyzed the mutant virions produced by transfected cells. Mutations that probably alter the structure of NCp7 structure led to the formation of very poorly infectious virus (A30P) or noninfectious virus (P31L and R32G). In addition, the P31L mutant did not contain detectable amounts of reverse transcriptase and had an immature core morphology, as determined by electron microscopy. On the other hand, mutations changing the basic nature of NCp7 had poor effect. R29S had a wild-type phenotype, and the replacement of 32RKK34 by SSS (S3 mutant) resulted in a decrease by no more than 100-fold of the virus titer. These results clearly show that the RAPRKKG linker contains residues that are critical for virion structure and infectivity.

Globular and disordered-the non-identical twins in protein-protein interactions

DEFF Research Database (Denmark)

Teilum, Kaare; Olsen, Johan Gotthardt; Kragelund, Birthe Brandt

2015-01-01

as a strong determinant for their function. This has fostered the notion that IDP's bind with low affinity but high specificity. Here we have analyzed available detailed thermodynamic data for protein-protein interactions to put to the test if the thermodynamic profiles of IDP interactions differ from those...... of other protein-protein interactions. We find that ordered proteins and the disordered ones act as non-identical twins operating by similar principles but where the disordered proteins complexes are on average less stable by 2.5 kcal mol(-1)....

Sequencing and Characterization of Novel PII Signaling Protein Gene in Microalga Haematococcus pluvialis

Directory of Open Access Journals (Sweden)

Ruijuan Ma

2017-10-01

Full Text Available The PII signaling protein is a key protein for controlling nitrogen assimilatory reactions in most organisms, but little information is reported on PII proteins of green microalga Haematococcus pluvialis. Since H. pluvialis cells can produce a large amount of astaxanthin upon nitrogen starvation, its PII protein may represent an important factor on elevated production of Haematococcus astaxanthin. This study identified and isolated the coding gene (HpGLB1 from this microalga. The full-length of HpGLB1 was 1222 bp, including 621 bp coding sequence (CDS, 103 bp 5′ untranslated region (5′ UTR, and 498 bp 3′ untranslated region (3′ UTR. The CDS could encode a protein with 206 amino acids (HpPII. Its calculated molecular weight (Mw was 22.4 kDa and the theoretical isoelectric point was 9.53. When H. pluvialis cells were exposed to nitrogen starvation, the HpGLB1 expression was increased 2.46 times in 48 h, concomitant with the raise of astaxanthin content. This study also used phylogenetic analysis to prove that HpPII was homogeneous to the PII proteins of other green microalgae. The results formed a fundamental basis for the future study on HpPII, for its potential physiological function in Haematococcus astaxanthin biosysthesis.

Seeing deconvolution of globular clusters in M31

International Nuclear Information System (INIS)

Bendinelli, O.; Zavatti, F.; Parmeggiani, G.; Djorgovski, S.

1990-01-01

The morphology of six M31 globular clusters is examined using seeing-deconvolved CCD images. The deconvolution techniques developed by Bendinelli (1989) are reviewed and applied to the M31 globular clusters to demonstrate the methodology. It is found that the effective resolution limit of the method is about 0.1-0.3 arcsec for CCD images obtained in FWHM = 1 arcsec seeing, and sampling of 0.3 arcsec/pixel. Also, the robustness of the method is discussed. The implications of the technique for future studies using data from the Hubble Space Telescope are considered. 68 refs

Vibrational energy flow in the villin headpiece subdomain: Master equation simulations

Energy Technology Data Exchange (ETDEWEB)

Leitner, David M., E-mail: dml@unr.edu, E-mail: stock@physik.uni-freiburg.de [Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, Nevada 89557 (United States); Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg (Germany); Buchenberg, Sebastian; Brettel, Paul [Biomolecular Dynamics, Institute of Physics, University of Freiburg, Freiburg (Germany); Stock, Gerhard, E-mail: dml@unr.edu, E-mail: stock@physik.uni-freiburg.de [Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg (Germany); Biomolecular Dynamics, Institute of Physics, University of Freiburg, Freiburg (Germany)

2015-02-21

We examine vibrational energy flow in dehydrated and hydrated villin headpiece subdomain HP36 by master equation simulations. Transition rates used in the simulations are obtained from communication maps calculated for HP36. In addition to energy flow along the main chain, we identify pathways for energy transport in HP36 via hydrogen bonding between residues quite far in sequence space. The results of the master equation simulations compare well with all-atom non-equilibrium simulations to about 1 ps following initial excitation of the protein, and quite well at long times, though for some residues we observe deviations between the master equation and all-atom simulations at intermediate times from about 1–10 ps. Those deviations are less noticeable for hydrated than dehydrated HP36 due to energy flow into the water.

Vibrational energy flow in the villin headpiece subdomain: Master equation simulations

International Nuclear Information System (INIS)

Leitner, David M.; Buchenberg, Sebastian; Brettel, Paul; Stock, Gerhard

2015-01-01

We examine vibrational energy flow in dehydrated and hydrated villin headpiece subdomain HP36 by master equation simulations. Transition rates used in the simulations are obtained from communication maps calculated for HP36. In addition to energy flow along the main chain, we identify pathways for energy transport in HP36 via hydrogen bonding between residues quite far in sequence space. The results of the master equation simulations compare well with all-atom non-equilibrium simulations to about 1 ps following initial excitation of the protein, and quite well at long times, though for some residues we observe deviations between the master equation and all-atom simulations at intermediate times from about 1–10 ps. Those deviations are less noticeable for hydrated than dehydrated HP36 due to energy flow into the water

Insulin sparing action of adenovirus 36 and its E4orf1 protein.

Science.gov (United States)

Dhurandhar, Nikhil V

2013-01-01

Additional drugs are required to effectively manage diabetes and its complications. Recent studies have revealed protective effects of Ad36, a human adenovirus, and its E4orf1 protein on glucose disposal, which may be creatively harnessed to develop novel anti-diabetic agents. Experimental Ad36 infection improves hyperglycemia in animal models and natural Ad36 infection in humans is associated with better glycemic control. Available data indicate distinctive advantages for a drug that may mimic the action of Ad36/E4orf1. The key features of such a potential drug include the ability to increase glucose uptake by adipose tissue and skeletal muscle, to reduce hepatic glucose output independent of proximal insulin signaling, and to up-regulate adiponectin and its hepatic action. The effect of Ad36/E4orf1 on hepatocyte metabolism suggests a role for treating hepatic steatosis. Despite these potential advantages, considerable research is required before such a drug is developed. The in vivo efficacy and safety of E4orf1 in improving hyperglycemia remain unknown, and an appropriate drug delivery system is required. Nonetheless, Ad36 E4orf1 offers a research opportunity to develop a new anti-diabetic agent with multiple potential advantages and conceptually advances the use of a rather unconventional source, microbial proteins, for anti-diabetic drug development. Copyright © 2013 Elsevier Inc. All rights reserved.

Statistical mechanics of protein solutions

NARCIS (Netherlands)

Prinsen, P.

2007-01-01

We study theoretically thermodynamic properties of spherical globular proteins in aqueous solution with added monovalent salt. We show how one can determine an effective interaction potential between the proteins from experimental data as a function of salt concentration and we apply this to the

Frequency of helicobacter pylori (hp) infection in children with recurrent abdominal pain (rap)

International Nuclear Information System (INIS)

Mahmud, S.; Ali, S.

2015-01-01

To study the frequency of Helicobacter Pylori (HP) infection among children with recurrent abdominal pain (RAP) Study Design: Cross-sectional comparative study. Place and Duration of Study: Military Hospital (MH), Rawalpindi from December 2011 to February 2012. Patients and Methods: One hundred children of either gender aged 2 to 12 years presenting with RAP were tested for HP at Paediatric OPD MH, Rawalpindi who consented to participate in the study. Those children who tested positive for Helicobacter Pylori Stool Antigen Test (HPSAT) were labeled as those having Hp infection. The stool assay was performed using the HpSAT kit and the socio-demographic and clinical profiles of children were associated. Results: Out of 100 children included in the study HpSAT was positive in 38% children. Frequency of Hp infection was significantly associated with source of drinking water (p = 0.014), socioeconomic status (p = 0.001) and positive family history of yspepsia (p= 0.023). While age and gender have no significant association with HP infection. Conclusion: Hp infection is very common in children presenting with RAP in our Paediatric OPD. Children with family history of dyspepsia, from low socioeconomic class and those drinking filtered water are at greater risk for HP infection. It is recommended that children from other populations in our country should also be tested in their medical health facilities in order to have a wider analysis of this problem in our setup. (author)

Observations of CO and OI in stars in globular clusters

International Nuclear Information System (INIS)

Wallerstein, G.; Pilachowski, C.

1978-01-01

Since studies at classification dispersion and early analyses of high dispersion spectra have yielded little quantitative data on the abundances of C, N, and O in globular clusters the authors have been endeavoring to establish their abundances in stars in several clusters. The problem has been approached in two ways, by observing the 2.3 micron CO bands and the 6300 A [OI] line in individual stars in globular clusters. (Auth.)

Effect of a High Protein Weight Loss Diet on Weight, High-Sensitivity C-Reactive Protein, and Cardiovascular Risk among Overweight and Obese Women: A Parallel Clinical Trial

Directory of Open Access Journals (Sweden)

Leila Azadbakht

2013-01-01

Full Text Available Studies regarding the effects of high protein (HP diets on cardiovascular (CVD risk factors have reported contradictory results. We aimed to determine the effects of an HP diet on CVD risk factors and high-sensitivity C-reactive protein (hs-CRP among overweight and obese women. In this randomized controlled trial, we recruited 60 overweight and obese women, aged 20–65, into an HP or energy-restricted control diet for three months (protein, carbohydrate, and fat: 25%, 45%, and 30% versus 15%, 55%, and 30%, resp.. Total protein was divided between animal and plant sources in a 1 : 1 ratio, and animal sources were distributed equally between meats and dairy products. Fasting blood samples, hs-CRP, lipid profile, systolic and diastolic blood pressure, and anthropometric measurements were assessed using standard guidelines. Percent change was significantly different between the two diet groups for weight (standard protein (SP: −3.90 ± 0.26 versus HP: −6.10 ± 0.34%; , resp. and waist circumference (SP: −3.03 ± 0.21 versus HP: −5.06 ± 0.28%; , resp.. Percent change of fasting blood glucose (FBG substantially decreased in the control group compared to the HP group (−9.13 ± 0.67 versus −4.93 ± 1.4%; P = 0.01, resp.. Total cholesterol, systolic blood pressure (SBP, and diastolic blood pressure (DBP decreased both in the HP and in the control diet groups (P = 0.06, P = 0.07, and P = 0.09, resp.; however, the results were marginally significant. Serum levels of hs-CRP were reduced both in the control (−0.08 ± 0.11%, P = 0.06 and in the high protein groups (−0.04 ± 0.09%, P = 0.06. The energy-restricted HP diet resulted in more beneficial effects on weight loss and reduction of waist circumference. CVD risk factors may improve with HP diets among overweight and obese women. When using isoenergetic weight loss diets, total cholesterol, hs-CRP, and SBP were marginally significantly reduced, independent of dietary protein content

The gamma-ray pulsar population of globular clusters: implications for the GeV excess

Energy Technology Data Exchange (ETDEWEB)

Hooper, Dan [Fermi National Accelerator Laboratory, Center for Particle Astrophysics, Batavia, IL 60510 (United States); Linden, Tim, E-mail: dhooper@fnal.gov, E-mail: linden.70@osu.edu [Ohio State University, Center for Cosmology and AstroParticle Physcis (CCAPP), Columbus, OH 43210 (United States)

2016-08-01

It has been suggested that the GeV excess, observed from the region surrounding the Galactic Center, might originate from a population of millisecond pulsars that formed in globular clusters. With this in mind, we employ the publicly available Fermi data to study the gamma-ray emission from 157 globular clusters, identifying a statistically significant signal from 25 of these sources (ten of which are not found in existing gamma-ray catalogs). We combine these observations with the predicted pulsar formation rate based on the stellar encounter rate of each globular cluster to constrain the gamma-ray luminosity function of millisecond pulsars in the Milky Way's globular cluster system. We find that this pulsar population exhibits a luminosity function that is quite similar to those millisecond pulsars observed in the field of the Milky Way (i.e. the thick disk). After pulsars are expelled from a globular cluster, however, they continue to lose rotational kinetic energy and become less luminous, causing their luminosity function to depart from the steady-state distribution. Using this luminosity function and a model for the globular cluster disruption rate, we show that millisecond pulsars born in globular clusters can account for only a few percent or less of the observed GeV excess. Among other challenges, scenarios in which the entire GeV excess is generated from such pulsars are in conflict with the observed mass of the Milky Way's Central Stellar Cluster.

A Science Portal and Archive for Extragalactic Globular Cluster Systems Data

Science.gov (United States)

Young, Michael; Rhode, Katherine L.; Gopu, Arvind

2015-01-01

For several years we have been carrying out a wide-field imaging survey of the globular cluster populations of a sample of giant spiral, S0, and elliptical galaxies with distances of ~10-30 Mpc. We use mosaic CCD cameras on the WIYN 3.5-m and Kitt Peak 4-m telescopes to acquire deep BVR imaging of each galaxy and then analyze the data to derive global properties of the globular cluster system. In addition to measuring the total numbers, specific frequencies, spatial distributions, and color distributions for the globular cluster populations, we have produced deep, high-quality images and lists of tens to thousands of globular cluster candidates for the ~40 galaxies included in the survey.With the survey nearing completion, we have been exploring how to efficiently disseminate not only the overall results, but also all of the relevant data products, to the astronomical community. Here we present our solution: a scientific portal and archive for extragalactic globular cluster systems data. With a modern and intuitive web interface built on the same framework as the WIYN One Degree Imager Portal, Pipeline, and Archive (ODI-PPA), our system will provide public access to the survey results and the final stacked mosaic images of the target galaxies. In addition, the astrometric and photometric data for thousands of identified globular cluster candidates, as well as for all point sources detected in each field, will be indexed and searchable. Where available, spectroscopic follow-up data will be paired with the candidates. Advanced imaging tools will enable users to overlay the cluster candidates and other sources on the mosaic images within the web interface, while metadata charting tools will allow users to rapidly and seamlessly plot the survey results for each galaxy and the data for hundreds of thousands of individual sources. Finally, we will appeal to other researchers with similar data products and work toward making our portal a central repository for data

Why fibrous proteins are romantic.

Science.gov (United States)

Cohen, C

1998-01-01

Here I give a personal account of the great history of fibrous protein structure. I describe how Astbury first recognized the essential simplicity of fibrous proteins and their paradigmatic role in protein structure. The poor diffraction patterns yielded by these proteins were then deciphered by Pauling, Crick, Ramachandran and others (in part by model building) to reveal alpha-helical coiled coils, beta-sheets, and the collagen triple helical coiled coil-all characterized by different local sequence periodicities. Longer-range sequence periodicities (or "magic numbers") present in diverse fibrous proteins, such as collagen, tropomyosin, paramyosin, myosin, and were then shown to account for the characteristic axial repeats observed in filaments of these proteins. More recently, analysis of fibrous protein structure has been extended in many cases to atomic resolution, and some systems, such as "leucine zippers," are providing a deeper understanding of protein design than similar studies of globular proteins. In the last sections, I provide some dramatic examples of fibrous protein dynamics. One example is the so-called "spring-loaded" mechanism for viral fusion by the hemagglutinin protein of influenza. Another is the possible conformational changes in prion proteins, implicated in "mad cow disease," which may be related to similar transitions in a variety of globular and fibrous proteins. Copyright 1998 Academic Press.

Two stellar-mass black holes in the globular cluster M22.

Science.gov (United States)

Strader, Jay; Chomiuk, Laura; Maccarone, Thomas J; Miller-Jones, James C A; Seth, Anil C

2012-10-04

Hundreds of stellar-mass black holes probably form in a typical globular star cluster, with all but one predicted to be ejected through dynamical interactions. Some observational support for this idea is provided by the lack of X-ray-emitting binary stars comprising one black hole and one other star ('black-hole/X-ray binaries') in Milky Way globular clusters, even though many neutron-star/X-ray binaries are known. Although a few black holes have been seen in globular clusters around other galaxies, the masses of these cannot be determined, and some may be intermediate-mass black holes that form through exotic mechanisms. Here we report the presence of two flat-spectrum radio sources in the Milky Way globular cluster M22, and we argue that these objects are black holes of stellar mass (each ∼10-20 times more massive than the Sun) that are accreting matter. We find a high ratio of radio-to-X-ray flux for these black holes, consistent with the larger predicted masses of black holes in globular clusters compared to those outside. The identification of two black holes in one cluster shows that ejection of black holes is not as efficient as predicted by most models, and we argue that M22 may contain a total population of ∼5-100 black holes. The large core radius of M22 could arise from heating produced by the black holes.

Spectroscopic confirmation of the first symbiotic star in a globular cluster

Science.gov (United States)

Zurek, David

2013-10-01

We have recently discovered an 18-minute period in the ultraviolet of a star in the globular cluster NGC 1851. In the redder optical bands, this star is red and bright, while it shows a clear UV excess relative to other stars at similar positions in the HR diagram. The system is most likely a symbiotic binary, composed of a cool evolved star and a white dwarf, with an 18 minute spin period, accreting the cool star's wind. The binary would be the first such object ever found in a globular cluster, and only the third in the Galaxy where the white dwarf spin period is measured. The only viable alternatives are that the two components are a chance superposition - something with a nontrivial chance of happening in a globular cluster core. In such a case, the 18 minute period would most likely be the spin period of a magnetic white dwarf in an intermediate polar cataclysmic variable {this would be the first confirmed magnetic CV in a globular cluster}, or the orbital period of a double-degenerate AM CVn binary. Each of these three possibilities show unique {and very different} emission line spectra in the blue wavelength range. Two orbits of HST with STIS/G430L will produce a spectrum of sufficient signal-to-noise to distinguish between these 3 scenarios. The result will be an important constraint on N-body models of globular clusters.

The Blue Hook Populations of Massive Globular Clusters

Science.gov (United States)

Brown, Thomas

2006-07-01

Blue hook stars are a class of hot { 35,000 K} subluminous horizontal branch stars that have been recently discovered using HST ultraviolet images of the globular clusters omega Cen and NGC 2808. These stars occupy a region of the HR diagram that is unexplained by canonical stellar evolution theory. Using new theoretical evolutionary and atmospheric models, we have shown that the blue hook stars are very likely the progeny of stars that undergo extensive internal mixing during a late helium core flash on the white dwarf cooling curve. This "flash mixing" produces an enormous enhancement of the surface helium and carbon abundances, which suppresses the flux in the far ultraviolet. Although flash mixing is more likely to occur in stars that are born with high helium abundances, a high helium abundance, by itself, does not explain the presence of a blue hook population - flash mixing of the envelope is required. We propose ACS ultraviolet {SBC/F150LP and HRC/F250W} observations of the five additional globular clusters for which the presence of blue hook stars is suspected from longer wavelength observations. Like omega Cen and NGC 2808, these five targets are also among the most massive globular clusters, because less massive clusters show no evidence for blue hook stars. Because our targets span 1.5 dex in metallicity, we will be able to test our prediction that flash-mixing should be less drastic in metal-rich blue hook stars. In addition, our observations will test the hypothesis that blue hook stars only form in globular clusters massive enough to retain the helium-enriched ejecta from the first stellar generation. If this hypothesis is correct, then our observations will yield important constraints on the chemical evolution and early formation history in globular clusters, as well as the role of helium self-enrichment in producing blue horizontal branch morphologies and multiple main sequence turnoffs. Finally, our observations will provide new insight into the

Enrichment of HP1a on Drosophila chromosome 4 genes creates an alternate chromatin structure critical for regulation in this heterochromatic domain.

Directory of Open Access Journals (Sweden)

Nicole C Riddle

2012-09-01

Full Text Available Chromatin environments differ greatly within a eukaryotic genome, depending on expression state, chromosomal location, and nuclear position. In genomic regions characterized by high repeat content and high gene density, chromatin structure must silence transposable elements but permit expression of embedded genes. We have investigated one such region, chromosome 4 of Drosophila melanogaster. Using chromatin-immunoprecipitation followed by microarray (ChIP-chip analysis, we examined enrichment patterns of 20 histone modifications and 25 chromosomal proteins in S2 and BG3 cells, as well as the changes in several marks resulting from mutations in key proteins. Active genes on chromosome 4 are distinct from those in euchromatin or pericentric heterochromatin: while there is a depletion of silencing marks at the transcription start sites (TSSs, HP1a and H3K9me3, but not H3K9me2, are enriched strongly over gene bodies. Intriguingly, genes on chromosome 4 are less frequently associated with paused polymerase. However, when the chromatin is altered by depleting HP1a or POF, the RNA pol II enrichment patterns of many chromosome 4 genes shift, showing a significant decrease over gene bodies but not at TSSs, accompanied by lower expression of those genes. Chromosome 4 genes have a low incidence of TRL/GAGA factor binding sites and a low T(m downstream of the TSS, characteristics that could contribute to a low incidence of RNA polymerase pausing. Our data also indicate that EGG and POF jointly regulate H3K9 methylation and promote HP1a binding over gene bodies, while HP1a targeting and H3K9 methylation are maintained at the repeats by an independent mechanism. The HP1a-enriched, POF-associated chromatin structure over the gene bodies may represent one type of adaptation for genes embedded in repetitive DNA.

Evolution of redback radio pulsars in globular clusters

Science.gov (United States)

Benvenuto, O. G.; De Vito, M. A.; Horvath, J. E.

2017-02-01

Context. We study the evolution of close binary systems composed of a normal, intermediate mass star and a neutron star considering a chemical composition typical of that present in globular clusters (Z = 0.001). Aims: We look for similarities and differences with respect to solar composition donor stars, which we have extensively studied in the past. As a definite example, we perform an application on one of the redbacks located in a globular cluster. Methods: We performed a detailed grid of models in order to find systems that represent the so-called redback binary radio pulsar systems with donor star masses between 0.6 and 2.0 solar masses and orbital periods in the range 0.2-0.9 d. Results: We find that the evolution of these binary systems is rather similar to those corresponding to solar composition objects, allowing us to account for the occurrence of redbacks in globular clusters, as the main physical ingredient is the irradiation feedback. Redback systems are in the quasi-RLOF state, that is, almost filling their corresponding Roche lobe. During the irradiation cycle the system alternates between semi-detached and detached states. While detached the system appears as a binary millisecond pulsar, called a redback. Circumstellar material, as seen in redbacks, is left behind after the previous semi-detached phase. Conclusions: The evolution of binary radio pulsar systems considering irradiation successfully accounts for, and provides a way for, the occurrence of redback pulsars in low-metallicity environments such as globular clusters. This is the case despite possible effects of the low metal content of the donor star that could drive systems away from redback configuration.

Spectral/ hp element methods: Recent developments, applications, and perspectives

Science.gov (United States)

Xu, Hui; Cantwell, Chris D.; Monteserin, Carlos; Eskilsson, Claes; Engsig-Karup, Allan P.; Sherwin, Spencer J.

2018-02-01

The spectral/ hp element method combines the geometric flexibility of the classical h-type finite element technique with the desirable numerical properties of spectral methods, employing high-degree piecewise polynomial basis functions on coarse finite element-type meshes. The spatial approximation is based upon orthogonal polynomials, such as Legendre or Chebychev polynomials, modified to accommodate a C 0 - continuous expansion. Computationally and theoretically, by increasing the polynomial order p, high-precision solutions and fast convergence can be obtained and, in particular, under certain regularity assumptions an exponential reduction in approximation error between numerical and exact solutions can be achieved. This method has now been applied in many simulation studies of both fundamental and practical engineering flows. This paper briefly describes the formulation of the spectral/ hp element method and provides an overview of its application to computational fluid dynamics. In particular, it focuses on the use of the spectral/ hp element method in transitional flows and ocean engineering. Finally, some of the major challenges to be overcome in order to use the spectral/ hp element method in more complex science and engineering applications are discussed.

Immunization with influenza virus hemagglutinin globular region containing the receptor-binding pocket.

Science.gov (United States)

Jeon, Sung Ho; Arnon, Ruth

2002-01-01

The globular region of hemagglutinin (residues 91-261) membrane glycoprotein of influenza virus that encompasses the binding zone to the oligosaccharide receptor of target cells has been cloned by reverse transcriptase-polymerase chain reaction (RT-PCR). This protein segment (denoted HA91-261 peptide) induced significant immune response in mice. The serum antibodies and lung homogenates from the immunized mice cross-reacted with native virus particles. The cellular immunity was manifested by proliferative splenocyte responses and cytokine release indicating T helper type 1 activity. The plasmid DNA containing this segment (denoted pHA91-261) provoked, in addition, a significant cytotoxic T lymphocyte (CTL) response, whereas the HA91-261 protein fragment led to no such response. Both the DNA and the protein fragment of HA91-261 induced significant protection against viral challenge, although the immune response they induce might be along different pathways. Interestingly, the combined DNA priming-protein boosting immunization regimen did not induce protection against viral challenges even though it led to significant humoral immune responses similar to that induced by the peptide vaccine.

Self-consistent field theory of protein adsorption in a non-Gaussian polyelectrolyte brush

NARCIS (Netherlands)

Biesheuvel, P.M.; Leermakers, F.A.M.; Stuart, M.A.C.

2006-01-01

To describe adsorption of globular protein molecules in a polyelectrolyte brush we use the strong-stretching approximation of the Edwards self-consistent field equation, combined with corrections for a non-Gaussian brush. To describe chemical potentials in this mixture of (globular) species of

Optimal design of PV and HP system

DEFF Research Database (Denmark)

Nepper-Rasmussen, Bjarke Christian; Rasmussen, Theis Bo

2015-01-01

Methods of utilizing residential produced photovoltaic (PV) power by converting to thermal energy through heat pumps (HP) are present in literature, where thermal energy is dispersed as either heat or hot water at the instant moment of PV production. In this paper an alternative solution is descr...... that the thermal storage with a BT is a better investment than a PV system without HP or no investment. Furthermore, it showed that the optimization model developed in this project is capable of finding the optimal combination of component sizes based on our data.......Methods of utilizing residential produced photovoltaic (PV) power by converting to thermal energy through heat pumps (HP) are present in literature, where thermal energy is dispersed as either heat or hot water at the instant moment of PV production. In this paper an alternative solution...... is described, where the thermal energy is stored in a buffer tank (BT) capable of dispersing heat to either the heating system of a house or a hot water tank, for later use. The thermal storage solution including a BT can increase the self-consumption of residentially produced PV power and thereby shift...

The Most Massive Star Clusters: Supermassive Globular Clusters or Dwarf Galaxy Nuclei?

Science.gov (United States)

Harris, William

2004-07-01

Evidence is mounting that the most massive globular clusters, such as Omega Centauri and M31-G1, may be related to the recently discovered "Ultra-Compact Dwarfs" and the dense nuclei of dE, N galaxies. However, no systematic imaging investigation of these supermassive globular clusters - at the level of Omega Cen and beyond - has been done, and we do not know what fraction of them might bear the signatures {such as large effective radii or tidal tails} of having originated as dE nuclei. We propose to use the ACS/WFC to obtain deep images of 18 such clusters in NGC 5128 and M31, the two nearest rich globular cluster systems. These globulars are the richest star clusters that can be found in nature, the biggest of them reaching 10^7 Solar masses, and they are likely to represent the results of star formation under the densest and most extreme conditions known. Using the profiles of the clusters including their faint outer envelopes, we will carry out state-of-the-art dynamical modelling of their structures, and look for any clear evidence which would indicate that they are associated with stripped satellites. This study will build on our previous work with STIS and WFPC2 imaging designed to study the 'Fundamental Plane' of globular clusters. When our new work is combined with Archival WFPC2, STIS, and ACS material, we will also be able to construct the definitive mapping of the Fundamental Plane of globular clusters at its uppermost mass range, and confirm whether or not the UCD and dE, N objects occupy a different structural parameter space.

Effect of the “protein diet” and bone tissue.

Science.gov (United States)

Nascimento da Silva, Zoraide; Azevedo de Jesuz, Vanessa; De Salvo Castro, Eduardo; Soares da Costa, Carlos Alberto; Teles Boaventura, Gilson; Blondet de Azeredo, Vilma

2014-01-01

The aim of this study is to evaluate the effect of the hyperproteic diet consumption on bone tissue. The study was conducted during sixty days. Twenty eight Wistar albinus rats, adults, originated from Laboratory of Experimental Nutrition were divided in four groups: (n = 7); Control 1 (C1), Control 2 (C2), Hyperproteic 1 (HP1) e Hyperproteic 2 (HP2). The C2 and HP2 groups were submitted to 30% of food restriction. The hyperproteic diet was based on the Atkins diet and prepared to simulate the protein diet. At the end of the study the animals were anesthetized to performer bone densitometry analyses by DEXA and blood and tissue collection. Serum and bone minerals analyses were conducted by colorimetric methods in automated equipment. The total bone mineral density (BMD) of the pelvis and the spine of the food restriction groups (HP2 e C2) were lower (p hyperproteic groups (HP1 e HP2). It was observed similar effect on the osteocalcin level, that presented lower (p hyperproteic groups. The insulin level was lower only in HP2 and serum calcium of the HP1 and HP2 groups was lower than C1. The protein diet promotes significant bone change on femur and in the hormones levels related to bone synthesis and maintenance of this tissue.

Peak {sup 14}CO{sub 2} excretion, symptoms and eradication of H.Pylori (HP) in patients with duodenal ulcer (DU)

Energy Technology Data Exchange (ETDEWEB)

Batholomeusz, F.D.L.; Bellon, M. [Royal Adelaide Hospital, Adelaide, SA (Australia). Department of Nuclear Medicine

1997-12-01

Full text: Many factors including drug efficacy, compliance and antibiotic resistance may influence HP eradication rates. The {sup 14}C urea breath test is a sensitive method of confirming HP colonisation and eradication. The aim was to study the relationships between the peak {sup 14}CO{sub 2} counts on the breath test prior to treatment, smoking and HP eradication, and to assess if persistent or recurrent symptoms implied failure of eradication. 117 patients with DU and HP colonisation proved on biopsy or rapid urease test who underwent {sup 14}C urea breath tests at least one month after eradication treatment was ceased were studied (69 male, 48 female, mean age 41, range 26-87 y). Questionnaire assessment of treatment regimen, smoking history and dyspeptic symptoms was made at the time of the breath test. A sub-group of 43 patients who had pre- and post-treatment breath tests was studied to assess if high peak {sup 14}CO{sub 2} counts on the pre-treatment breath test related to treatment success. The mean peak initial {sup 14}CO{sub 2} excretion in those who were treated successfully was 4187 (+ 472) counts/min and for failures 4817 (+739) counts/min (p 0.24). Dyspeptic symptoms were present in 36% of patients treated successfully and 37% where treatment failed. The eradication rate for the 56 smokers was 75 per cent, and the 61 non-smokers 83%. (p>0.2) High {sup 14}CO{sub 2} excretion on the initial {sup 14}C urea breath test and smoking are not associated with a significantly lower rate of HP eradication and the presence of dyspepsia is not a good indicator of persistent infection

HP-Lattice QSAR for dynein proteins: experimental proteomics (2D-electrophoresis, mass spectrometry) and theoretic study of a Leishmania infantum sequence.

Science.gov (United States)

Dea-Ayuela, María Auxiliadora; Pérez-Castillo, Yunierkis; Meneses-Marcel, Alfredo; Ubeira, Florencio M; Bolas-Fernández, Francisco; Chou, Kuo-Chen; González-Díaz, Humberto

2008-08-15

The toxicity and inefficacy of actual organic drugs against Leishmaniosis justify research projects to find new molecular targets in Leishmania species including Leishmania infantum (L. infantum) and Leishmaniamajor (L. major), both important pathogens. In this sense, quantitative structure-activity relationship (QSAR) methods, which are very useful in Bioorganic and Medicinal Chemistry to discover small-sized drugs, may help to identify not only new drugs but also new drug targets, if we apply them to proteins. Dyneins are important proteins of these parasites governing fundamental processes such as cilia and flagella motion, nuclear migration, organization of the mitotic splinde, and chromosome separation during mitosis. However, despite the interest for them as potential drug targets, so far there has been no report whatsoever on dyneins with QSAR techniques. To the best of our knowledge, we report here the first QSAR for dynein proteins. We used as input the Spectral Moments of a Markov matrix associated to the HP-Lattice Network of the protein sequence. The data contain 411 protein sequences of different species selected by ClustalX to develop a QSAR that correctly discriminates on average between 92.75% and 92.51% of dyneins and other proteins in four different train and cross-validation datasets. We also report a combined experimental and theoretic study of a new dynein sequence in order to illustrate the utility of the model to search for potential drug targets with a practical example. First, we carried out a 2D-electrophoresis analysis of L. infantum biological samples. Next, we excised from 2D-E gels one spot of interest belonging to an unknown protein or protein fragment in the region Mdata base with the highest similarity score to the MS of the protein isolated from L. infantum. We used the QSAR model to predict the new sequence as dynein with probability of 99.99% without relying upon alignment. In order to confirm the previous function annotation we

Informative gene selection using Adaptive Analytic Hierarchy Process (A2HP

Directory of Open Access Journals (Sweden)

Abhishek Bhola

2017-12-01

Full Text Available Gene expression dataset derived from microarray experiments are marked by large number of genes, which contains the gene expression values at different sample conditions/time-points. Selection of informative genes from these large datasets is an issue of major concern for various researchers and biologists. In this study, we propose a gene selection and dimensionality reduction method called Adaptive Analytic Hierarchy Process (A2HP. Traditional analytic hierarchy process is a multiple-criteria based decision analysis method whose result depends upon the expert knowledge or decision makers. It is mainly used to solve the decision problems in different fields. On the other hand, A2HP is a fused method that combines the outcomes of five individual gene selection ranking methods t-test, chi-square variance test, z-test, wilcoxon test and signal-to-noise ratio (SNR. At first, the preprocessing of gene expression dataset is done and then the reduced number of genes obtained, will be fed as input for A2HP. A2HP utilizes both quantitative and qualitative factors to select the informative genes. Results demonstrate that A2HP selects efficient number of genes as compared to the individual gene selection methods. The percentage of deduction in number of genes and time complexity are taken as the performance measure for the proposed method. And it is shown that A2HP outperforms individual gene selection methods.

Ubiquitin ligase RNF123 mediates degradation of heterochromatin protein 1α and β in lamin A/C knock-down cells.

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Pankaj Chaturvedi

Full Text Available The nuclear lamina is a key determinant of nuclear architecture, integrity and functionality in metazoan nuclei. Mutations in the human lamin A gene lead to highly debilitating genetic diseases termed as laminopathies. Expression of lamin A mutations or reduction in levels of endogenous A-type lamins leads to nuclear defects such as abnormal nuclear morphology and disorganization of heterochromatin. This is accompanied by increased proteasomal degradation of certain nuclear proteins such as emerin, nesprin-1α, retinoblastoma protein and heterochromatin protein 1 (HP1. However, the pathways of proteasomal degradation have not been well characterized.To investigate the mechanisms underlying the degradation of HP1 proteins upon lamin misexpression, we analyzed the effects of shRNA-mediated knock-down of lamins A and C in HeLa cells. Cells with reduced levels of expression of lamins A and C exhibited proteasomal degradation of HP1α and HP1β but not HP1γ. Since specific ubiquitin ligases are upregulated in lamin A/C knock-down cells, further studies were carried out with one of these ligases, RNF123, which has a putative HP1-binding motif. Ectopic expression of GFP-tagged RNF123 directly resulted in degradation of HP1α and HP1β. Mutational analysis showed that the canonical HP1-binding pentapeptide motif PXVXL in the N-terminus of RNF123 was required for binding to HP1 proteins and targeting them for degradation. The role of endogenous RNF123 in the degradation of HP1 isoforms was confirmed by RNF123 RNAi experiments. Furthermore, FRAP analysis suggested that HP1β was displaced from chromatin in laminopathic cells.Our data support a role for RNF123 ubiquitin ligase in the degradation of HP1α and HP1β upon lamin A/C knock-down. Hence lamin misexpression can cause degradation of mislocalized proteins involved in key nuclear processes by induction of specific components of the ubiquitin-proteasome system.

Globular and disordered – the non-identical twins in protein-protein interactions

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Kaare eTeilum

2015-07-01

Full Text Available In biology proteins from different structural classes interact across and within classes in ways that are optimized to achieve balanced functional outputs. The interactions between intrinsically disordered proteins (IDPs and other proteins rely on changes in flexibility and this is seen as a strong determinant for their function. This has fostered the notion that IDP’s bind with low affinity but high specificity. Here we have analyzed available detailed thermodynamic data for protein-protein interactions to put to the test if the thermodynamic profiles of IDP interactions differ from those of other protein-protein interactions. We find that ordered proteins and the disordered ones act as non identical twins operating by similar principles but where the disordered proteins complexes are on average less stable by 2.5 kcal mol-1.

Globular adiponectin induces a pro-inflammatory response in human astrocytic cells

International Nuclear Information System (INIS)

Wan, Zhongxiao; Mah, Dorrian; Simtchouk, Svetlana; Klegeris, Andis; Little, Jonathan P.

2014-01-01

Highlights: • Adiponectin receptors are expressed in human astrocytes. • Globular adiponectin induces secretion of IL-6 and MCP-1 from cultured astrocytes. • Adiponectin may play a pro-inflammatory role in astrocytes. - Abstract: Neuroinflammation, mediated in part by activated brain astrocytes, plays a critical role in the development of neurodegenerative disorders, including Alzheimer’s disease (AD). Adiponectin is the most abundant adipokine secreted from adipose tissue and has been reported to exert both anti- and pro-inflammatory effects in peripheral tissues; however, the effects of adiponectin on astrocytes remain unknown. Shifts in peripheral concentrations of adipokines, including adiponectin, could contribute to the observed link between midlife adiposity and increased AD risk. The aim of the present study was to characterize the effects of globular adiponectin (gAd) on pro-inflammatory cytokine mRNA expression and secretion in human U373 MG astrocytic cells and to explore the potential involvement of nuclear factor (NF)-κB, p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and phosphatidylinositide 3-kinases (PI3 K) signaling pathways in these processes. We demonstrated expression of adiponectin receptor 1 (adipoR1) and adipoR2 in U373 MG cells and primary human astrocytes. gAd induced secretion of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1, and gene expression of IL-6, MCP-1, IL-1β and IL-8 in U373 MG cells. Using specific inhibitors, we found that NF-κB, p38MAPK and ERK1/2 pathways are involved in gAd-induced induction of cytokines with ERK1/2 contributing the most. These findings provide evidence that gAd may induce a pro-inflammatory phenotype in human astrocytes

Globular adiponectin induces a pro-inflammatory response in human astrocytic cells

Energy Technology Data Exchange (ETDEWEB)

Wan, Zhongxiao; Mah, Dorrian; Simtchouk, Svetlana [School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC (Canada); Klegeris, Andis [Department of Biology, University of British Columbia Okanagan, Kelowna, BC (Canada); Little, Jonathan P., E-mail: jonathan.little@ubc.ca [School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC (Canada)

2014-03-28

Highlights: • Adiponectin receptors are expressed in human astrocytes. • Globular adiponectin induces secretion of IL-6 and MCP-1 from cultured astrocytes. • Adiponectin may play a pro-inflammatory role in astrocytes. - Abstract: Neuroinflammation, mediated in part by activated brain astrocytes, plays a critical role in the development of neurodegenerative disorders, including Alzheimer’s disease (AD). Adiponectin is the most abundant adipokine secreted from adipose tissue and has been reported to exert both anti- and pro-inflammatory effects in peripheral tissues; however, the effects of adiponectin on astrocytes remain unknown. Shifts in peripheral concentrations of adipokines, including adiponectin, could contribute to the observed link between midlife adiposity and increased AD risk. The aim of the present study was to characterize the effects of globular adiponectin (gAd) on pro-inflammatory cytokine mRNA expression and secretion in human U373 MG astrocytic cells and to explore the potential involvement of nuclear factor (NF)-κB, p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and phosphatidylinositide 3-kinases (PI3 K) signaling pathways in these processes. We demonstrated expression of adiponectin receptor 1 (adipoR1) and adipoR2 in U373 MG cells and primary human astrocytes. gAd induced secretion of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1, and gene expression of IL-6, MCP-1, IL-1β and IL-8 in U373 MG cells. Using specific inhibitors, we found that NF-κB, p38MAPK and ERK1/2 pathways are involved in gAd-induced induction of cytokines with ERK1/2 contributing the most. These findings provide evidence that gAd may induce a pro-inflammatory phenotype in human astrocytes.

An observational study of disk-population globular clusters

International Nuclear Information System (INIS)

Armandroff, T.E.

1988-01-01

Integrated-light spectroscopy was obtained for twenty-seven globular clusters at the Ca II infrared triplet. Line strengths and radial velocities were measured from the spectra. For the well-studied clusters in the sample, the strength of the CA II lines is very well correlated with previous metallicity estimates obtained using a variety of techniques. The greatly reduced effect of interstellar extinction at these wavelengths compared to the blue region of the spectrum has permitted observations of some of the most heavily reddened clusters in the Galaxy. For several such clusters, the Ca II triplet metallicities are in poor agreement with metallicity estimates from infrared photometry by Malkan. Color-magnitude diagrams were constructed for six previously unstudied metal-rich globular clusters and for the well-studied cluster 47 Tuc. The V magnitudes of the horizontal branch stars in the six clusters are in poor agreement with previous estimates based on secondary methods. The horizontal branch morphologies and reddenings of the program clusters were also determined. Using the improved set of metallicities, radial velocities, and distance moduli, the spatial distribution, kinematics, and metallicity distribution of the Galactic globulars were analyzed. The revised data supports Zinn's conclusion that the metal-rich clusters form a highly flattened, rapidly rotating disk system, while the metal-poor clusters make up the familiar, spherically distributed, slowly rotating halo population. The scale height, metallicity distribution, and kinematics of the metal-rich globulars are in good agreement with those of the stellar thick disk. Luminosity functions were constructed, and no significant difference is found between disk and halo samples. Metallicity gradients seem to be present in the disk cluster system. The implications of these results for the formation and evol

AcEST: BP917936 [AcEST

Lifescience Database Archive (English)

Full Text Available terized protein (Fragmen... 36 1.0 tr|B0W1A0|B0W1A0_CULQU Shuttle craft OS=Culex quinquefasciatus G... 35 1.... Query: 38 HP 33 HP Sbjct: 161 HP 162 >tr|B0W1A0|B0W1A0_CULQU Shuttle craft OS=Cu

HP1330 Contributes to Streptococcus suis Virulence by Inducing Toll-Like Receptor 2- and ERK1/2-Dependent Pro-inflammatory Responses and Influencing In Vivo S. suis Loads

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Qiang Zhang

2017-07-01

Full Text Available Streptococcus suis 2 (SS2 has evolved into a highly invasive pathogen responsible for two large-scale outbreaks of streptococcal toxic shock-like syndrome (STSLS in China. Excessive inflammation stimulated by SS2 is considered a hallmark of STSLS, even it also plays important roles in other clinical symptoms of SS2-related disease, including meningitis, septicemia, and sudden death. However, the mechanism of SS2-caused excessive inflammation remains poorly understood. Here, a novel pro-inflammatory protein was identified (HP1330, which could induce robust expression of pro-inflammatory cytokines (TNF-α, MCP-1, and IL-1β in RAW264.7 macrophages. To evaluate the role of HP1330 in SS2 virulence, an hp1330-deletion mutant (Δhp1330 was constructed. In vitro, hp1330 disruption led to a decreased pro-inflammatory ability of SS2 in RAW 264.7 macrophages. In vivo, Δhp1330 showed reduced lethality, pro-inflammatory activity, and bacterial loads in mice. To further elucidate the mechanism of HP1330-induced pro-inflammatory cytokine production, antibody blocking and gene-deletion experiments with macrophages were performed. The results revealed that the pro-inflammatory activity of HP1330 depended on the recognition of toll-like receptor 2 (TLR2. Furthermore, a specific inhibitor of the extracellular signal-regulated kinase 1/2 (ERK1/2 pathways could significantly decrease HP1330-induced pro-inflammatory cytokine production, and western blot analysis showed that HP1330 could induce activation of the ERK1/2 pathway. Taken together, our findings demonstrate that HP1330 contributes to SS2 virulence by inducing TLR2- and ERK1/2-dependent pro-inflammatory cytokine production and influencing in vivo bacterial loads, implying that HP1330 may be associated with STSLS caused by SS2.

Recruitment of the cohesin loading factor NIPBL to DNA double-strand breaks depends on MDC1, RNF168 and HP1γ in human cells

International Nuclear Information System (INIS)

Oka, Yasuyoshi; Suzuki, Keiji; Yamauchi, Motohiro; Mitsutake, Norisato; Yamashita, Shunichi

2011-01-01

Highlights: → NIPBL is recruited to DSBs. → Localization of NIPBL to DSBs is regulated by MDC1 and RNF168. → HP1γ is required for NIPBL accumulation at DSBs. -- Abstract: The cohesin loading factor NIPBL is required for cohesin to associate with chromosomes and plays a role in DNA double-strand break (DSB) repair. Although the NIPBL homolog Scc2 is recruited to an enzymatically generated DSB and promotes cohesin-dependent DSB repair in yeast, the mechanism of the recruitment remains poorly understood. Here we show that the human NIPBL is recruited to the sites of DNA damage generated by micro-irradiation as well as to the sites of DSBs induced by homing endonuclease, I-PpoI. The recruitment of NIPBL was impaired by RNAi-mediated knockdown of MDC1 or RNF168, both of which also accumulate at DSBs. We also show that the recruitment of NIPBL to the sites of DNA damage is mediated by its C-terminal region containing HEAT repeats and Heterochromatin protein 1 (HP1) interacting motif. Furthermore, NIPBL accumulation at damaged sites was also compromised by HP1γ depletion. Taken together, our study reveals that human NIPBL is a novel protein recruited to DSB sites, and the recruitment is controlled by MDC1, RNF168 and HP1γ.

Notes on HP1 a software package for simulating variably-saturated water flow, heat transport, solute transport, and biogeochemistry in porous media. HP1 Version 2.2

Energy Technology Data Exchange (ETDEWEB)

Jacques, D.; Simunek, J.

2010-01-15

HP1 is a comprehensive modeling tool in terms of processes and reactions for simulating reactive transport and biogeochemical processes in variably-saturated porous media. HP1 results from coupling the water and solute transport model HYDRUS-1D (Simunek et al., 2009a) and PHREEQC-2 (Parkhurst and Appelo, 1999). This note provides an overview of how to set up and execute a HP1 project using version 2.2.002 of HP1 and version 4.13 of the graphical user interface (GUI) of HYDRUS-1D. A large part of this note are step-by-step instructions for selected examples involving mineral dissolution and precipitation, cation exchange, surface complexation and kinetic degradation networks. The implementation of variably-saturated flow conditions, changing boundary conditions, a layered soil profile or immobile water is also illustrated.

Notes on HP1 a software package for simulating variably-saturated water flow, heat transport, solute transport, and biogeochemistry in porous media. HP1 Version 2.2

International Nuclear Information System (INIS)

Jacques, D.; Simunek, J.

2010-01-01

HP1 is a comprehensive modeling tool in terms of processes and reactions for simulating reactive transport and biogeochemical processes in variably-saturated porous media. HP1 results from coupling the water and solute transport model HYDRUS-1D (Simunek et al., 2009a) and PHREEQC-2 (Parkhurst and Appelo, 1999). This note provides an overview of how to set up and execute a HP1 project using version 2.2.002 of HP1 and version 4.13 of the graphical user interface (GUI) of HYDRUS-1D. A large part of this note are step-by-step instructions for selected examples involving mineral dissolution and precipitation, cation exchange, surface complexation and kinetic degradation networks. The implementation of variably-saturated flow conditions, changing boundary conditions, a layered soil profile or immobile water is also illustrated.

Rates of collapse and evaporation of globular clusters

Science.gov (United States)

Hut, Piet; Djorgovski, S.

1992-01-01

Observational estimates of the dynamical relaxation times of Galactic globular clusters are used here to estimate the present rate at which core collapse and evaporation are occurring in them. A core collapse rate of 2 +/- 1 per Gyr is found, which for a Galactic age of about 12 Gyr agrees well with the fact that 27 clusters have surface brightness profiles with the morphology expected for the postcollapse phase. A destruction and evaporation rate of 5 +/- 3 per Gyr is found, suggesting that a significant fraction of the Galaxy's original complement of globular clusters have perished through the combined effects of mechanisms such as relaxation-driven evaporation and shocking due to interaction with the Galactic disk and bulge.

Systematic discovery of new recognition peptides mediating protein interaction networks

DEFF Research Database (Denmark)

Neduva, Victor; Linding, Rune; Su-Angrand, Isabelle

2005-01-01

Many aspects of cell signalling, trafficking, and targeting are governed by interactions between globular protein domains and short peptide segments. These domains often bind multiple peptides that share a common sequence pattern, or "linear motif" (e.g., SH3 binding to PxxP). Many domains...... by interactions between globular protein domains and short peptide segments. These domains often bind multiple peptides that share a common sequence pattern, or "linear motif" (e.g., SH3 binding to PxxP). Many domains are known, though comparatively few linear motifs have been discovered. Their short length...

Effects of heat on meat proteins - Implications on structure and quality of meat products.

Science.gov (United States)

Tornberg, E

2005-07-01

Globular and fibrous proteins are compared with regard to structural behaviour on heating, where the former expands and the latter contracts. The meat protein composition and structure is briefly described. The behaviour of the different meat proteins on heating is discussed. Most of the sarcoplasmic proteins aggregate between 40 and 60 °C, but for some of them the coagulation can extend up to 90°C. For myofibrillar proteins in solution unfolding starts at 30-32°C, followed by protein-protein association at 36-40°C and subsequent gelation at 45-50°C (conc.>0.5% by weight). At temperatures between 53 and 63°C the collagen denaturation occurs, followed by collagen fibre shrinkage. If the collagen fibres are not stabilised by heat-resistant intermolecular bonds, it dissolves and forms gelatine on further heating. The structural changes on cooking in whole meat and comminuted meat products, and the alterations in water-holding and texture of the meat product that it leads to, are then discussed.

The transport kinetics and selectivity of HpUreI, the urea channel from Helicobacter pylori†

Science.gov (United States)

Gray, Lawrence R; Gu, Sean X; Quick, Matthias; Khademi, Shahram

2017-01-01

Helicobacter pylori’s unique ability to colonize and survive in the acidic environment of the stomach is critically dependent on uptake of urea through the urea channel, HpUreI. Hence, HpUreI may represent a promising target for the development of specific drugs against this human pathogen. To obtain insight into the structure/function relationship of this channel, we have developed conditions for the high-yield expression and purification of stable recombinant HpUreI that allowed its detailed kinetic characterization in solubilized form and reconstituted into liposomes. Detergent-solubilized HpUreI forms homo-trimer, as determined by chemical cross-linking. Urea dissociation kinetics of purified HpUreI were determined by means of the scintillation proximity assay (SPA), whereas urea efflux was measured in HpUreI-containing proteoliposomes using stopped-flow spectrometry to determine the kinetics and selectivity of the urea channel. The kinetic analyses revealed that urea conduction in HpUreI is pH sensitive and saturable with a half-saturation concentration (or K0.5) of ~163 mM. Binding of urea by HpUreI was increased at lower pH; however, the apparent affinity of urea binding (~150 mM) was not significantly pH dependent. The solute selectivity analysis indicated that HpUreI is highly selective for urea and hydroxyurea. Removing either amino group of urea molecules diminishes their permeability through HpUreI. Similar to urea conduction, water diffusion through HpUreI is pH-dependent with low water permeability at neutral pH. PMID:21877689

Effect of radiation pressure in the cores of globular clusters

Energy Technology Data Exchange (ETDEWEB)

Angeletti, L; Capuzzo-Dolcetta, R; Giannone

1981-10-01

The possible effects of a presence of a dust cloud in the cores of globular clusters was investigated. Two cluster models were considered together with various models of clouds. The problem of radiation transfer was solved under some simplifying assumptions. Owing to a differential absorption of the star light in the cloud, radiation pressure turned out be inward-directed in some cloud models. This fact may lead to a confinement of some dust in the central regions of globular clusters.

Globular clusters as a source of X-ray emission from the neighbourhood of M87

International Nuclear Information System (INIS)

Fabian, A.C.; Pringle, J.E.; Rees, M.J.

1976-01-01

It is stated that the X-ray emission from globular clusters may be attributable to accretion on to compact objects, the accreting material being supplied from binary companions, or gas trapped in the potential well of the cluster. Counts of objects in the vicinity of the M87 have revealed that it has an extensive halo of globular clusters, the number of which may exceed 10,000 within a radius of 23 arc min. Most of these clusters may be explicable as a population effect, and the similarity of their optical properties to those of cluster in our own Galaxy suggests that they may also contain X-ray sources. The brighter globular clusters in M87 may, however, be substantially more X-ray luminous, and there may be proportionally more gas available in globular clusters in M87 compared with our Galaxy. The average X-ray luminosity of individual globular clusters may be of the order of 10 38 erg/sec., which raises the possibility that the integrated globular cluster emission may account for a substantial fraction of the X-ray emission observed from the region of M87. In support of this it is noted that the extended X-ray emission from the Virgo cluster is centered on M87, which lies approximately 45 arc min from the cluster centroid, and it is expected that the general X-ray emission from the globular cluster will appear to be smoothly and symmetrically distributed about M87 at moderate spatial resolution. A similar situation may apply to the elliptical galaxy NGC 3311 in Abell 1060 which, as a cluster, has been suggested as the identification for the X-ray source 3 U 1044-40, and it seems possible that that galaxy is surrounded by a similar globular cluster population to that of M87. (U.K.)

Chemical Abundances of Giants in Globular Clusters

Science.gov (United States)

Gratton, Raffaele G.; Bragaglia, Angela; Carretta, Eugenio; D'Orazi, Valentina; Lucatello, Sara

A large fraction of stars form in clusters. According to a widespread paradigma, stellar clusters are prototypes of single stellar populations. According to this concept, they formed on a very short time scale, and all their stars share the same chemical composition. Recently it has been understood that massive stellar clusters (the globular clusters) rather host various stellar populations, characterized by different chemical composition: these stellar populations have also slightly different ages, stars of the second generations being formed from the ejecta of part of those of an earlier one. Furthermore, it is becoming clear that the efficiency of the process is quite low: many more stars formed within this process than currently present in the clusters. This implies that a significant, perhaps even dominant fraction of the ancient population of galaxies formed within the episodes that lead to formation the globular clusters.

The evoluation of the galactic globular clusters; I Metal abundance calibrations

International Nuclear Information System (INIS)

Lee, S.W.; Park, N.K.

1984-01-01

Five different calibrations of metal abundances of globular clusters are examined and these are compared with metallicity ranking parameters such as (Sp)sub(c), , Q39 and IR-indices. Except for the calibration *(Fe/H*)sub(H) by the high dispersion echelle analysis, the other calibration scales are correlated with the morphological parameters of red giant branch. In the *(Fe/H*)sub(Hsup(-))scale, the clusters later than approx.F8 have nearly a constant metal abundance, *(Fe/H*)sub(H)approx.-1.05, regardless of morphological characteristics of horizontal branch and red giant branch. By the two fundamental calibration scales of *(Fe/H*)sub(L) (derived by the low dispersion analysis), and *(Fe/H*)sub(delta S) (derived by the spectral analysis of RR Lyrae stars), the globular clusters are divided into the halo clusters with *(Fe/H*)<-1.0 and the disk clusters confined within the galactocentric distance rsub(G)=10 kpc and galactic plane distance absolute z=3 kpc. In this case the abundance gradient is given by d*(Fe/H*)/drsub(G)approx.-0.05kpcsup(-1) and d*(Fe/H*)/d absolute z approx. -0.08 kpcsup(-1) within rsub(G)=20 kpc and absolute z=10 kpc, respectively. According to these characteristics of the spatial distribution of globular clusters, the chemical evolution of the galactic globular clusters can be accounted for by the two-zone (disk-halo) slow collapse model when the *(Fe/H*)sub(Lsup(-)) or *(Fe/H*)sub(DELTA Ssup(-))scale is applied. In the case of *(Fe/H*)sub(Hsup(-))scale, the one-zone fast collapse model is preferred for the evolution of globular clusters. (Author)

A catalogue of masses, structural parameters and velocity dispersion profiles of 112 Milky Way globular clusters

Science.gov (United States)

Baumgardt, H.; Hilker, M.

2018-05-01

We have determined masses, stellar mass functions and structural parameters of 112 Milky Way globular clusters by fitting a large set of N-body simulations to their velocity dispersion and surface density profiles. The velocity dispersion profiles were calculated based on a combination of more than 15,000 high-precision radial velocities which we derived from archival ESO/VLT and Keck spectra together with ˜20, 000 published radial velocities from the literature. Our fits also include the stellar mass functions of the globular clusters, which are available for 47 clusters in our sample, allowing us to self-consistently take the effects of mass segregation and ongoing cluster dissolution into account. We confirm the strong correlation between the global mass functions of globular clusters and their relaxation times recently found by Sollima & Baumgardt (2017). We also find a correlation of the escape velocity from the centre of a globular cluster and the fraction of first generation stars (FG) in the cluster recently derived for 57 globular clusters by Milone et al. (2017), but no correlation between the FG star fraction and the global mass function of a globular cluster. This could indicate that the ability of a globular cluster to keep the wind ejecta from the polluting star(s) is the crucial parameter determining the presence and fraction of second generation stars and not its later dynamical mass loss.

Binary Black Hole Mergers from Globular Clusters: Implications for Advanced LIGO.

Science.gov (United States)

Rodriguez, Carl L; Morscher, Meagan; Pattabiraman, Bharath; Chatterjee, Sourav; Haster, Carl-Johan; Rasio, Frederic A

2015-07-31

The predicted rate of binary black hole mergers from galactic fields can vary over several orders of magnitude and is extremely sensitive to the assumptions of stellar evolution. But in dense stellar environments such as globular clusters, binary black holes form by well-understood gravitational interactions. In this Letter, we study the formation of black hole binaries in an extensive collection of realistic globular cluster models. By comparing these models to observed Milky Way and extragalactic globular clusters, we find that the mergers of dynamically formed binaries could be detected at a rate of ∼100 per year, potentially dominating the binary black hole merger rate. We also find that a majority of cluster-formed binaries are more massive than their field-formed counterparts, suggesting that Advanced LIGO could identify certain binaries as originating from dense stellar environments.

HP fotovõistluse finalistid veebis / Henrik Roonemaa

Index Scriptorium Estoniae

Roonemaa, Henrik

2002-01-01

Hewlett-Packardi koduleheküljel on üleval rahvusvahelise digitaalfotograafia konkursi HP Invision Digital Photography Awards 2002 finalistide tööd, nende hulgas Katrin Arraku foto "Minu kala Vallo"

A simple model for electrical charge in globular macromolecules and linear polyelectrolytes in solution

Science.gov (United States)

Krishnan, M.

2017-05-01

We present a model for calculating the net and effective electrical charge of globular macromolecules and linear polyelectrolytes such as proteins and DNA, given the concentration of monovalent salt and pH in solution. The calculation is based on a numerical solution of the non-linear Poisson-Boltzmann equation using a finite element discretized continuum approach. The model simultaneously addresses the phenomena of charge regulation and renormalization, both of which underpin the electrostatics of biomolecules in solution. We show that while charge regulation addresses the true electrical charge of a molecule arising from the acid-base equilibria of its ionizable groups, charge renormalization finds relevance in the context of a molecule's interaction with another charged entity. Writing this electrostatic interaction free energy in terms of a local electrical potential, we obtain an "interaction charge" for the molecule which we demonstrate agrees closely with the "effective charge" discussed in charge renormalization and counterion-condensation theories. The predictions of this model agree well with direct high-precision measurements of effective electrical charge of polyelectrolytes such as nucleic acids and disordered proteins in solution, without tunable parameters. Including the effective interior dielectric constant for compactly folded molecules as a tunable parameter, the model captures measurements of effective charge as well as published trends of pKa shifts in globular proteins. Our results suggest a straightforward general framework to model electrostatics in biomolecules in solution. In offering a platform that directly links theory and experiment, these calculations could foster a systematic understanding of the interrelationship between molecular 3D structure and conformation, electrical charge and electrostatic interactions in solution. The model could find particular relevance in situations where molecular crystal structures are not available or

Tinker-HP: a massively parallel molecular dynamics package for multiscale simulations of large complex systems with advanced point dipole polarizable force fields.

Science.gov (United States)

Lagardère, Louis; Jolly, Luc-Henri; Lipparini, Filippo; Aviat, Félix; Stamm, Benjamin; Jing, Zhifeng F; Harger, Matthew; Torabifard, Hedieh; Cisneros, G Andrés; Schnieders, Michael J; Gresh, Nohad; Maday, Yvon; Ren, Pengyu Y; Ponder, Jay W; Piquemal, Jean-Philip

2018-01-28

We present Tinker-HP, a massively MPI parallel package dedicated to classical molecular dynamics (MD) and to multiscale simulations, using advanced polarizable force fields (PFF) encompassing distributed multipoles electrostatics. Tinker-HP is an evolution of the popular Tinker package code that conserves its simplicity of use and its reference double precision implementation for CPUs. Grounded on interdisciplinary efforts with applied mathematics, Tinker-HP allows for long polarizable MD simulations on large systems up to millions of atoms. We detail in the paper the newly developed extension of massively parallel 3D spatial decomposition to point dipole polarizable models as well as their coupling to efficient Krylov iterative and non-iterative polarization solvers. The design of the code allows the use of various computer systems ranging from laboratory workstations to modern petascale supercomputers with thousands of cores. Tinker-HP proposes therefore the first high-performance scalable CPU computing environment for the development of next generation point dipole PFFs and for production simulations. Strategies linking Tinker-HP to Quantum Mechanics (QM) in the framework of multiscale polarizable self-consistent QM/MD simulations are also provided. The possibilities, performances and scalability of the software are demonstrated via benchmarks calculations using the polarizable AMOEBA force field on systems ranging from large water boxes of increasing size and ionic liquids to (very) large biosystems encompassing several proteins as well as the complete satellite tobacco mosaic virus and ribosome structures. For small systems, Tinker-HP appears to be competitive with the Tinker-OpenMM GPU implementation of Tinker. As the system size grows, Tinker-HP remains operational thanks to its access to distributed memory and takes advantage of its new algorithmic enabling for stable long timescale polarizable simulations. Overall, a several thousand-fold acceleration over

Amyloid fibril formation in vitro from halophilic metal binding protein: Its high solubility and reversibility minimized formation of amorphous protein aggregations

Science.gov (United States)

Tokunaga, Yuhei; Matsumoto, Mitsuharu; Tokunaga, Masao; Arakawa, Tsutomu; Sugimoto, Yasushi

2013-01-01

Halophilic proteins are characterized by high net negative charges and relatively small fraction of hydrophobic amino acids, rendering them aggregation resistant. These properties are also shared by histidine-rich metal binding protein (HP) from moderate halophile, Chromohalobacter salexigens, used in this study. Here, we examined how halophilic proteins form amyloid fibrils in vitro. His-tagged HP, incubated at pH 2.0 and 58°C, readily formed amyloid fibrils, as observed by thioflavin fluorescence, CD spectra, and transmission or atomic force microscopies. Under these low-pH harsh conditions, however, His-HP was promptly hydrolyzed to smaller peptides most likely responsible for rapid formation of amyloid fibril. Three major acid-hydrolyzed peptides were isolated from fibrils and turned out to readily form fibrils. The synthetic peptides predicted to form fibrils in these peptide sequences by Waltz software also formed fibrils. Amyloid fibril was also readily formed from full-length His-HP when incubated with 10–20% 2,2,2-trifluoroethanol at pH 7.8 and 25°C without peptide bond cleavage. PMID:24038709

On tidal radius determination for a globular cluster

International Nuclear Information System (INIS)

Ninkovic, S.

1985-01-01

A tidal radius determination for a globular cluster based on its density minimum, which is caused by the galactic tidal forces and derivable from a model of the Galaxy, is proposed. Results obtained on the basis of the Schmidt model for two clusters are in a satisfactory agreement with those obtained earlier by means of other methods. A mass determination for the clusters through the tidal radius, when the latter one is identified with the cluster perigalactic distance, yields unusually large mass values. Probably, the tidal radius should be identified with the instantaneous galactocentric distance. Use of models more recent than the Schmidt one indicates that a globular cluster may contain a significant portion of an invisible interstellar matter. (author)

Dynamic variation of histone H3 trimethyl Lys4 (H3K4me3) and heterochromatin protein 1 (HP1) with employment length in nickel smelting workers.

Science.gov (United States)

Zhao, Yanhong; Cheng, Ning; Dai, Min; Pu, Hongquan; Zheng, Tongzhang; Li, Haiyan; He, Jie; Bai, Yana

2017-07-01

To investigate the dynamic variation in H3K4me3 and HP1 with employment length in nickel smelting workers. Blood samples were collected from 140 nickel smelting workers and 140 age-matched office workers to test for H3K4me3, and HP1 levels. H3K4me3 was statistically significantly different (p exposure to nickel can induce oxidative damage, and increase H3K4me3 expression and inhibit HP1 expression.

Globular Cluster Candidates for Hosting a Central Black Hole

Science.gov (United States)

Noyola, Eva

2009-07-01

We are continuing our study of the dynamical properties of globular clusters and we propose to obtain surface brightness profiles for high concentration clusters. Our results to date show that the distribution of central surface brightness slopes do not conform to standard models. This has important implications for how they form and evolve, and suggest the possible presence of central intermediate-mass black holes. From our previous archival proposals {AR-9542 and AR-10315}, we find that many high concentration globular clusters do not have flat cores or steep central cusps, instead they show weak cusps. Numerical simulations suggest that clusters with weak cusps may harbor intermediate-mass black holes and we have one confirmation of this connection with omega Centauri. This cluster shows a shallow cusp in its surface brightness profile, while kinematical measurements suggest the presence of a black hole in its center. Our goal is to extend these studies to a sample containing 85% of the Galactic globular clusters with concentrations higher than 1.7 and look for objects departing from isothermal behavior. The ACS globular cluster survey {GO-10775} provides enough objects to have an excellent coverage of a wide range of galactic clusters, but it contains only a couple of the ones with high concentration. The proposed sample consists of clusters whose light profile can only be adequately measured from space-based imaging. This would take us close to completeness for the high concentration cases and therefore provide a more complete list of candidates for containing a central black hole. The dataset will also be combined with our existing kinematic measurements and enhanced with future kinematic studies to perform detailed dynamical modeling.

HUBBLE PINPOINTS WHITE DWARFS IN GLOBULAR CLUSTER

Science.gov (United States)

2002-01-01

Peering deep inside a cluster of several hundred thousand stars, NASA's Hubble Space Telescope uncovered the oldest burned-out stars in our Milky Way Galaxy. Located in the globular cluster M4, these small, dying stars - called white dwarfs - are giving astronomers a fresh reading on one of the biggest questions in astronomy: How old is the universe? The ancient white dwarfs in M4 are about 12 to 13 billion years old. After accounting for the time it took the cluster to form after the big bang, astronomers found that the age of the white dwarfs agrees with previous estimates for the universe's age. In the top panel, a ground-based observatory snapped a panoramic view of the entire cluster, which contains several hundred thousand stars within a volume of 10 to 30 light-years across. The Kitt Peak National Observatory's 0.9-meter telescope took this picture in March 1995. The box at left indicates the region observed by the Hubble telescope. The Hubble telescope studied a small region of the cluster. A section of that region is seen in the picture at bottom left. A sampling of an even smaller region is shown at bottom right. This region is only about one light-year across. In this smaller region, Hubble pinpointed a number of faint white dwarfs. The blue circles pinpoint the dwarfs. It took nearly eight days of exposure time over a 67-day period to find these extremely faint stars. Globular clusters are among the oldest clusters of stars in the universe. The faintest and coolest white dwarfs within globular clusters can yield a globular cluster's age. Earlier Hubble observations showed that the first stars formed less than 1 billion years after the universe's birth in the big bang. So, finding the oldest stars puts astronomers within arm's reach of the universe's age. M4 is 7,000 light-years away in the constellation Scorpius. Hubble's Wide Field and Planetary Camera 2 made the observations from January through April 2001. These optical observations were combined to

Identification of Hard X-ray Sources in Galactic Globular Clusters: Simbol-X Simulations

Science.gov (United States)

Servillat, M.

2009-05-01

Globular clusters harbour an excess of X-ray sources compared to the number of X-ray sources in the Galactic plane. It has been proposed that many of these X-ray sources are cataclysmic variables that have an intermediate magnetic field, i.e. intermediate polars, which remains to be confirmed and understood. We present here several methods to identify intermediate polars in globular clusters from multiwavelength analysis. First, we report on XMM-Newton, Chandra and HST observations of the very dense Galactic globular cluster NGC 2808. By comparing UV and X-ray properties of the cataclysmic variable candidates, the fraction of intermediate polars in this cluster can be estimated. We also present the optical spectra of two cataclysmic variables in the globular cluster M 22. The HeII (4868 Å) emission line in these spectra could be related to the presence of a magnetic field in these objects. Simulations of Simbol-X observations indicate that the angular resolution is sufficient to study X-ray sources in the core of close, less dense globular clusters, such as M 22. The sensitivity of Simbol-X in an extended energy band up to 80 keV will allow us to discriminate between hard X-ray sources (such as magnetic cataclysmic variables) and soft X-ray sources (such as chromospherically active binaries).

Depletion-induced instability in protein-DNA mixtures: Influence of protein charge and size

NARCIS (Netherlands)

Vries, de R.J.

2006-01-01

While there is abundant experimental and theoretical work on polymer-induced DNA condensation, it is still unclear whether globular proteins can condense linear DNA or not. We develop a simple analytical approximation for the depletion attraction between rodlike segments of semiflexible

Integrated-light spectroscopy of globular clusters at the infrared Ca II lines

Science.gov (United States)

Armandroff, Taft E.; Zinn, Robert

1988-01-01

Integrated-light spectroscopy has been obtained for 27 globular clusters at the Ca II IR triplet. Line strengths and radial velocities have been measured from the spectra. For the well-studied clusters in the sample, the strength of the Ca II lines is very well correlated with previous metallicity estimates. Thus, the triplet is useful as a metallicity indicator in globular cluster integrated-light spectra. The greatly reduced effect of interstellar extinction at these wavelengths (compared to the blue region of the spectrum) has permitted observations of some of the most heavily reddened clusters in the Galaxy. For several such clusters, the Ca II triplet metallicities are in poor agreement with metallicity estimates from IR photometry by Malkan (1981). The strength of an interstellar band at 8621A has been used to estimate the amount of extinction towards these clusters. Using the new metallicity and radial-velocity data, the metallicity distribution, kinematics, and spatial distribution of the disk globular cluster system have been analyzed. Results very similar to those of Zinn (1985) have been found. The relation of the disk globulars to the stellar thick disk is discussed.

Disrupted globular clusters and the gamma-ray excess in the Galactic Centre

Science.gov (United States)

Fragione, Giacomo; Antonini, Fabio; Gnedin, Oleg Y.

2018-04-01

The Fermi Large Area Telescope has provided the most detailed view towards the Galactic Centre (GC) in high-energy gamma-rays. Besides the interstellar emission and point source contributions, the data suggest a residual diffuse gamma-ray excess. The similarity of its spatial distribution with the expected profile of dark matter has led to claims that this may be evidence for dark matter particle annihilation. Here, we investigate an alternative explanation that the signal originates from millisecond pulsars (MSPs) formed in dense globular clusters and deposited at the GC as a consequence of cluster inspiral and tidal disruption. We use a semi-analytical model to calculate the formation, migration, and disruption of globular clusters in the Galaxy. Our model reproduces the mass of the nuclear star cluster and the present-day radial and mass distribution of globular clusters. For the first time, we calculate the evolution of MSPs from disrupted globular clusters throughout the age of the Galaxy and consistently include the effect of the MSP spin-down due to magnetic-dipole braking. The final gamma-ray amplitude and spatial distribution are in good agreement with the Fermi observations and provide a natural astrophysical explanation for the GC excess.

The CompHP Core Competencies Framework for Health Promotion in Europe

Science.gov (United States)

Barry, Margaret M.; Battel-Kirk, Barbara; Dempsey, Colette

2012-01-01

Background: The CompHP Project on Developing Competencies and Professional Standards for Health Promotion in Europe was developed in response to the need for new and changing health promotion competencies to address health challenges. This article presents the process of developing the CompHP Core Competencies Framework for Health Promotion across…

Application of far-infrared spectroscopy to the structural identification of protein materials.

Science.gov (United States)

Han, Yanchen; Ling, Shengjie; Qi, Zeming; Shao, Zhengzhong; Chen, Xin

2018-05-03

Although far-infrared (IR) spectroscopy has been shown to be a powerful tool to determine peptide structure and to detect structural transitions in peptides, it has been overlooked in the characterization of proteins. Herein, we used far-IR spectroscopy to monitor the structure of four abundant non-bioactive proteins, namely, soybean protein isolate (SPI), pea protein isolate (PPI) and two types of silk fibroins (SFs), domestic Bombyx mori and wild Antheraea pernyi. The two globular proteins SPI and PPI result in broad and weak far-IR bands (between 50 and 700 cm-1), in agreement with those of some other bioactive globular proteins previously studied (lysozyme, myoglobin, hemoglobin, etc.) that generally only have random amino acid sequences. Interestingly, the two SFs, which are characterized by a structure composed of highly repetitive motifs, show several sharp far-IR characteristic absorption peaks. Moreover, some of these characteristic peaks (such as the peaks at 260 and 428 cm-1 in B. mori, and the peaks at 245 and 448 cm-1 in A. pernyi) are sensitive to conformational changes; hence, they can be directly used to monitor conformational transitions in SFs. Furthermore, since SF absorption bands clearly differ from those of globular proteins and different SFs even show distinct adsorption bands, far-IR spectroscopy can be applied to distinguish and determine the specific SF component within protein blends.

Helicobacter pylori stool antigen test (HpSA) for the diagnosis of gastric infection

International Nuclear Information System (INIS)

Faruqui, A.N.; Majid, U.; Ahmed, L.; Khalil, M.; Hussan, M.U.

2007-01-01

To determine the accuracy of Helicobacter pylori Stool Antigen test (HpSA), compared with endoscopic histopathology for the diagnosis of gastric Helicobecter pylori infection. A total of 50 patients underwent endoscopy for gastric antral mucosal tissue biopsy for histopathology of H.pylori and advised for HpSA. Patient's information including age, gender, past history, presenting signs and symptoms, results of HpSA and histopathology were recorded. Sensitivity analysis was performed to calculate sensitivity, specificity, and predictive values of HpSA. Among 50 patients, 48% males and 52% females (M: F 1: 1.08), a total of 27 (54%) were true positive while 20 (40%) were true negative. Two patients were false negative and only one was false positive. Sensitivity of HpSA was, therefore, 93.1%, specificity 95% and positive and negative predictive values were 96.42% and 90.9% respectively. Helicobacter pylori stool antigen was an accurate and reliable test for the diagnosis of gastric H. pylori infection. (author)

The ellipticities of a sample of globular clusters in M31

International Nuclear Information System (INIS)

Lupton, R.H.

1989-01-01

Images for a sample of 18 globular clusters in M31 have been obtained. The mean ellipticity on the sky in the range 7-14 pc (2-4 arcsec) is 0.08 + or - 0.02 and 0.12 + or - 0.01 in the range 14-21 pc (4-6 arcsec), with corresponding true ellipticities of 0.12 and 0.18. The difference between the inner and outer parts is significant at a 99 percent level. The flattening of the inner parts is statistically indistinguishable from that of the Galactic globular clusters, while the outer parts are flatter than the Galactic clusters at a 99.8 percent confidence level. There is a significant anticorrelation of ellipticity with line strength; such a correlation may in retrospect also be seen in the Galactic globular cluster system. For the M31 data, this anticorrelation is stronger in the inner parts of the galaxy. 30 refs

The Frequency of Binary Stars in the Globular Cluster M71

Science.gov (United States)

Barden, S. C.; Armandroff, T. E.; Pryor, C. P.

1994-12-01

The frequency of binary stars is a fundamental property of a stellar population. A comparison of the frequency of binaries in globular clusters with those in the field halo and disk populations tests the similarity of star formation in those environments. Binary stars in globular clusters also act as an energy source which ``heats" the cluster through super-elastic encounters with other stars and binaries. Such encounters can not only profoundly affect the dynamical evolution of the cluster, they can disrupt the widely separated binaries and catalyze the formation of exotic objects such as blue stragglers, x-ray binaries, and milli-second pulsars. We have used the KPNO 4-m and the multi-fiber instruments Nessie and Hydra to measure radial velocities at 4 epochs over two years for a sample of 126 stars in the globular cluster M71. Velocity errors are under 1 km s(-1) for the brighter stars and under 2 km s(-1) for the majority of our data set. These velocities will be valuable for studying the kinematics of M71, but here we focus on searching for binaries. The faintest stars are at V=17, or just above the main sequence turnoff. Our sample is thus deeper than any published globular cluster binary search utilizing spectroscopic techniques. By observing smaller stars, we double the number of decades of binary periods sampled compared to previous studies and come within a factor of 4 of the shortest possible periods for turnoff stars. This wider period window has produced the largest known sample of binaries in a globular cluster. Four stars show velocity ranges larger than 20 km s(-1) , nine have ranges larger than 10 km s(-1) , and others are clearly variable. We will compare the radial distribution of these stars to that predicted by theory and derive the main-sequence binary fraction.

Recombinant Protein Truncation Strategy for Inducing Bactericidal Antibodies to the Macrophage Infectivity Potentiator Protein of Neisseria meningitidis and Circumventing Potential Cross-Reactivity with Human FK506-Binding Proteins

Science.gov (United States)

Bielecka, Magdalena K.; Devos, Nathalie; Gilbert, Mélanie; Hung, Miao-Chiu; Weynants, Vincent; Heckels, John E.

2014-01-01

A recombinant macrophage infectivity potentiator (rMIP) protein of Neisseria meningitidis induces significant serum bactericidal antibody production in mice and is a candidate meningococcal vaccine antigen. However, bioinformatics analysis of MIP showed some amino acid sequence similarity to human FK506-binding proteins (FKBPs) in residues 166 to 252 located in the globular domain of the protein. To circumvent the potential concern over generating antibodies that could recognize human proteins, we immunized mice with recombinant truncated type I rMIP proteins that lacked the globular domain and the signal leader peptide (LP) signal sequence (amino acids 1 to 22) and contained the His purification tag at either the N or C terminus (C-term). The immunogenicity of truncated rMIP proteins was compared to that of full (i.e., full-length) rMIP proteins (containing the globular domain) with either an N- or C-terminal His tag and with or without the LP sequence. By comparing the functional murine antibody responses to these various constructs, we determined that C-term His truncated rMIP (−LP) delivered in liposomes induced high levels of antibodies that bound to the surface of wild-type but not Δmip mutant meningococci and showed bactericidal activity against homologous type I MIP (median titers of 128 to 256) and heterologous type II and III (median titers of 256 to 512) strains, thereby providing at least 82% serogroup B strain coverage. In contrast, in constructs lacking the LP, placement of the His tag at the N terminus appeared to abrogate bactericidal activity. The strategy used in this study would obviate any potential concerns regarding the use of MIP antigens for inclusion in bacterial vaccines. PMID:25452551

Recombinant protein truncation strategy for inducing bactericidal antibodies to the macrophage infectivity potentiator protein of Neisseria meningitidis and circumventing potential cross-reactivity with human FK506-binding proteins.

Science.gov (United States)

Bielecka, Magdalena K; Devos, Nathalie; Gilbert, Mélanie; Hung, Miao-Chiu; Weynants, Vincent; Heckels, John E; Christodoulides, Myron

2015-02-01

A recombinant macrophage infectivity potentiator (rMIP) protein of Neisseria meningitidis induces significant serum bactericidal antibody production in mice and is a candidate meningococcal vaccine antigen. However, bioinformatics analysis of MIP showed some amino acid sequence similarity to human FK506-binding proteins (FKBPs) in residues 166 to 252 located in the globular domain of the protein. To circumvent the potential concern over generating antibodies that could recognize human proteins, we immunized mice with recombinant truncated type I rMIP proteins that lacked the globular domain and the signal leader peptide (LP) signal sequence (amino acids 1 to 22) and contained the His purification tag at either the N or C terminus (C-term). The immunogenicity of truncated rMIP proteins was compared to that of full (i.e., full-length) rMIP proteins (containing the globular domain) with either an N- or C-terminal His tag and with or without the LP sequence. By comparing the functional murine antibody responses to these various constructs, we determined that C-term His truncated rMIP (-LP) delivered in liposomes induced high levels of antibodies that bound to the surface of wild-type but not Δmip mutant meningococci and showed bactericidal activity against homologous type I MIP (median titers of 128 to 256) and heterologous type II and III (median titers of 256 to 512) strains, thereby providing at least 82% serogroup B strain coverage. In contrast, in constructs lacking the LP, placement of the His tag at the N terminus appeared to abrogate bactericidal activity. The strategy used in this study would obviate any potential concerns regarding the use of MIP antigens for inclusion in bacterial vaccines. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Dynamics of proteins and of their hydration layer studied by neutron scattering and additional biophysical methods

International Nuclear Information System (INIS)

Gallat, Francois-Xavier

2011-01-01

This thesis work focused on the dynamics of proteins, surrounded by their hydration layer, a water shell around the protein vital for its biological function. Each of these components is accompanied by a specific dynamics which union reforms the complex energy landscape of the system. The joint implementation of selective deuteration, incoherent neutron scattering and tera-hertz spectroscopy allowed to explore the dynamics of proteins and that of the hydration shell. The influence of the folding state of protein on its dynamics has been studied by elastic neutron scattering. Globular proteins were less dynamic than its intrinsically disordered analogues. Themselves appear to be stiffer than non-physiological unfolded proteins. The oligomerization state and the consequences on the dynamics were investigated. Aggregates of a globular protein proved to be more flexible than the soluble form. In contrast, aggregates of a disordered protein showed lower average dynamics compared to the soluble form. These observations demonstrate the wide range of dynamics among the proteome. Incoherent neutron scattering experiences on the hydration layer of globular and disordered proteins have yielded information on the nature of water motion around these proteins. The measurements revealed the presence of translational motions concomitant with the onset of the transition dynamics of hydration layers, at 220 K. Measurements have also shown a stronger coupling between a disordered protein and its hydration water, compared to a globular protein and its hydration shell. The nature of the hydration layer and its influence on its dynamics has been explored with the use of polymers that mimic the water behavior and that act as a source of flexibility for the protein. Eventually, the dynamics of methyl groups involved in the dynamical changes observed at 150 and 220 K, was investigated. (author) [fr

Interdependence of the rad50 hook and globular domain functions.

Science.gov (United States)

Hohl, Marcel; Kochańczyk, Tomasz; Tous, Cristina; Aguilera, Andrés; Krężel, Artur; Petrini, John H J

2015-02-05

Rad50 contains a conserved Zn(2+) coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn(2+)-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions. Copyright © 2015 Elsevier Inc. All rights reserved.

The Age of Globular Clusters in Light of Hipparcos: Resolving the Age Problem?

Science.gov (United States)

Chaboyer, Brian; Demarque, P.; Kernan, Peter J.; Krauss, Lawrence M.

1998-02-01

We review five independent techniques that are used to set the distance scale to globular clusters, including subdwarf main-sequence fitting utilizing the recent Hipparcos parallax catalog. These data together all indicate that globular clusters are farther away than previously believed, implying a reduction in age estimates. We now adopt a best-fit value Mv (RR Lyrae stars) = 0.39 +/- 0.08 (statistical) at [Fe/H] = -1.9 with an additional uniform systematic uncertainty of +0.13-0.18. This new distance scale estimate is combined with a detailed numerical Monte Carlo study (previously reported by Chaboyer et al.) designed to assess the uncertainty associated with the theoretical age-turnoff luminosity relationship in order to estimate both the absolute age and uncertainty in age of the oldest globular clusters. Our best estimate for the mean age of the oldest globular clusters is now 11.5 +/- 1.3 Gyr, with a one-sided 95% confidence level lower limit of 9.5 Gyr. This represents a systematic shift of over 2 σ compared to our earlier estimate, owing completely to the new distance scale--a shift which we emphasize results not only from the Hipparcos data. This now provides a lower limit on the age of the universe that is consistent with either an open universe or with a flat matter-dominated universe (the latter requiring H0 explicitly quantifies how remaining uncertainties in the distance scale and stellar evolution models translate into uncertainties in the derived globular cluster ages. Simple formulae are provided that can be used to update our age estimate as improved determinations for various quantities become available. Formulae are also provided that can be used to derive the age and its uncertainty for a globular cluster, given the absolute magnitude of the turnoff or the point on the subgiant branch 0.05 mag redder than the turnoff.

Measuring age differences among globular clusters having similar metallicities - A new method and first results

International Nuclear Information System (INIS)

Vandenberg, D.A.; Bolte, M.; Stetson, P.B.

1990-01-01

A color-difference technique for estimating the relative ages of globular clusters with similar chemical compositions on the basis of their CM diagrams is described and demonstrated. The theoretical basis and implementation of the procedure are explained, and results for groups of globular clusters with m/H = about -2, -1.6, and -1.3, and for two special cases (Palomar 12 and NGC 5139) are presented in extensive tables and graphs and discussed in detail. It is found that the more metal-deficient globular clusters are nearly coeval (differences less than 0.5 Gyr), whereas the most metal-rich globular clusters exhibit significant age differences (about 2 Gyr). This result is shown to contradict Galactic evolution models postulating halo collapse in less than a few times 100 Myr. 77 refs

Recombinant Protein Truncation Strategy for Inducing Bactericidal Antibodies to the Macrophage Infectivity Potentiator Protein of Neisseria meningitidis and Circumventing Potential Cross-Reactivity with Human FK506-Binding Proteins

OpenAIRE

Bielecka, Magdalena K.; Devos, Nathalie; Gilbert, Mélanie; Hung, Miao-Chiu; Weynants, Vincent; Heckels, John E.; Christodoulides, Myron

2014-01-01

A recombinant macrophage infectivity potentiator (rMIP) protein of Neisseria meningitidis induces significant serum bactericidal antibody production in mice and is a candidate meningococcal vaccine antigen. However, bioinformatics analysis of MIP showed some amino acid sequence similarity to human FK506-binding proteins (FKBPs) in residues 166 to 252 located in the globular domain of the protein. To circumvent the potential concern over generating antibodies that could recognize human protein...

A spectroscopic and photometric study of MSP companions in Galactic Globular Clusters

OpenAIRE

Cocozza, Gabriele

2008-01-01

This Thesis is devoted to the study of the optical companions of Millisecond Pulsars in Galactic Globular Clusters (GCs) as a part of a large project started at the Department of Astronomy of the Bologna University, in collaboration with other institutions (Astronomical Observatory of Cagliari and Bologna, University of Virginia), specifically dedicated to the study of the environmental effects on passive stellar evolution in galactic GCs. Globular Clusters are very efficien...

Is age really the second parameter in globular clusters?

International Nuclear Information System (INIS)

Vandenberg, D.A.; Durrell, P.R.

1990-01-01

From the close similarity of the magnitude difference between the tip of the red giant branch and the turnoff in the Fe/H = about -1.3 globular cluster NGC 288, NGC 362, and M5, it is inferred that the ages of these three systems (and Palomar 5, whose horizonal branch is used to define its distance relative to the others) are not detectably different. An identical conclusion, by similar means, is reached for the Fe/H = about -2.1 globular clusters M15, M30, M68, and M92. Several recent claims that age is responsible for the wide variation in horizontal-branch morphology among clusters of the same metal abundance are not supported. 73 refs

Ruprecht 106 - A young metal-poor Galactic globular cluster

International Nuclear Information System (INIS)

Buonanno, R.; Buscema, G.; Fusi Pecci, F.; Richer, H.B.; Fahlman, G.G.

1990-01-01

The first CCD photometric survey in the Galactic globular cluster Ruprecht 106 has been performed. The results show that Ruprecht 106 is a metal-poor cluster with (Fe/H) about -2 located at about 25 kpc from the Galactic center. A sizable, high centrally concentrated population of blue stragglers was detected. Significant differences in the positions of the turnoffs in the color-magnitude diagram are found compared to those in metal-poor clusters. The cluster appears younger than other typical metal-poor Galactic globulars by about 4-5 Gyr; if true, this object would represent the first direct proof of the existence of a significant age spread among old, very metal-poor clusters. 51 refs

Color maps of X-ray globular clusters

International Nuclear Information System (INIS)

Bailyn, C.D.; Grindlay, J.E.; Cohn, H.; Lugger, P.M.

1988-01-01

The results of a search for optical counterparts to X-ray sources in six globular clusters, 47 Tuc, NGC 1851, NGC 6441, NGC 6624, NGC 6712, and M15, are reported. Maps of the U-B color of the central regions of the clusters were prepared. A candidate for the optical counterpart of the source in NGC 6712 was found, along with a blue region near the X-ray source in 47 Tuc. Upper limits on the colors and magnitudes of possible optical counterparts are reported for the other three clusters. The use of color maps to determine color gradients in globular clusters is explored. It is found that, while such gradients do exist and vary from cluster to cluster, they can be explained by crowding effects. Crude limits are placed on the excess populations of blue objects such as CVs, which have been postulated to be concentrated in the centers of dense clusters. 32 references

Human diploid fibroblasts have receptors for the globular domain of C1Q

International Nuclear Information System (INIS)

Bordin, S.; Page, R.C.

1986-01-01

The authors showed that mass cultures of fibroblasts grown from gingival explants in DB medium with 10% human serum are enriched in a phenotype that binds C1q with an affinity much higher than the rest of the population. Because of potential biologic importance of C1q receptors, the authors studied whether the interaction between C1q and this phenotype was mediated by the globular or collagenous domains of the molecule. Globular fragments were prepared by digesting C1q with collagenase, and collagenous fragments obtained after pepsin treatment. C1q binding on cells in suspension was determined by reaction with 125 I-C1q as reported. Competition experiments were performed under conditions in which intact 125 I-C1q binding saturated all available receptors. The results showed that collagenous fragments inhibited 20% of the 125 I-C1q binding to high affinity receptors, whereas inhibition by globular fragments was 70%. Unlabeled intact C1q and collagen type 1 were used as controls, and inhibited 92% and 17% of C1q binding, respectively. These studies show that C1q interacts with the fibroblast phenotype expressing high affinity receptors through its globular domain. The authors suggest that at sites of trauma, native C1 may bind to the surface of these cells via the globular domain of C1q, and that this unique phenotype may play an important role in tissue repair

General requirements to implement the personal dose equivalent Hp(10) in Brazil

International Nuclear Information System (INIS)

Lopes, Amanda Gomes; Silva, Francisco Cesar Augusto da

2017-01-01

To update the dosimetry quantity with the international community, Brazil is changing the Individual Dose Hx to the Personal Dose Equivalent Hp(10). A bibliographical survey on the technical and administrative requirements of nine countries that use Hp(10) was carried out to obtain the most relevant ones. All of them follow IEC and ISO guidelines for technical requirements, while administrative requirements change from country to country. Based on countries experiences, this paper presents a list of important general requirements to implement Hp(10) and to prepare the Brazilian requirements according to the international scientific community. (author)

General requirements to implement the personal dose equivalent Hp(10) in Brazil

Energy Technology Data Exchange (ETDEWEB)

Lopes, Amanda Gomes; Silva, Francisco Cesar Augusto da, E-mail: amandagl@bolsista.ird.gov.br [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

To update the dosimetry quantity with the international community, Brazil is changing the Individual Dose Hx to the Personal Dose Equivalent Hp(10). A bibliographical survey on the technical and administrative requirements of nine countries that use Hp(10) was carried out to obtain the most relevant ones. All of them follow IEC and ISO guidelines for technical requirements, while administrative requirements change from country to country. Based on countries experiences, this paper presents a list of important general requirements to implement Hp(10) and to prepare the Brazilian requirements according to the international scientific community. (author)

Keck Spectroscopy of Globular Clusters in the Elliptical Galaxy NGC 3610

OpenAIRE

Strader, Jay; Brodie, Jean P.; Schweizer, Francois; Larsen, Soeren S.; Seitzer, Patrick

2002-01-01

We present moderate-resolution Keck spectra of nine candidate globular clusters in the possible merger-remnant elliptical galaxy NGC 3610. Eight of the objects appear to be bona fide globular clusters of NGC 3610. We find that two of the clusters belong to an old metal-poor population, five to an old metal-rich population, and only one to an intermediate-age metal-rich population. The estimated age of the intermediate-age cluster is 1-5 Gyr, which is in agreement with earlier estimates of the...

Speckle imaging of globular clusters

International Nuclear Information System (INIS)

Sams, B.J. III

1990-01-01

Speckle imaging is a powerful tool for high resolution astronomy. Its application to the core regions of globular clusters produces high resolution stellar maps of the bright stars, but is unable to image the faint stars which are most reliable dynamical indicators. The limits on resolving these faint, extended objects are physical, not algorithmic, and cannot be overcome using speckle. High resolution maps may be useful for resolving multicomponent stellar systems in the cluster centers. 30 refs

Urinary 1-hydroxypyrene (1-HP) in environmental and occupational studies--a review

DEFF Research Database (Denmark)

Hansen, Ase M; Mathiesen, Line; Pedersen, Marie

2008-01-01

, volume (and time) or concentrations of creatinine are often used to standardize for diuresis. To be able to compare the included studies we recalculated the given concentrations to mumol 1-HP/mol creatinine. In conclusion, the highest concentrations of urinary 1-HP are found among workers...

NOA36 Protein Contains a Highly Conserved Nucleolar Localization Signal Capable of Directing Functional Proteins to the Nucleolus, in Mammalian Cells

Science.gov (United States)

de Melo, Ivan S.; Jimenez-Nuñez, Maria D.; Iglesias, Concepción; Campos-Caro, Antonio; Moreno-Sanchez, David; Ruiz, Felix A.; Bolívar, Jorge

2013-01-01

NOA36/ZNF330 is an evolutionarily well-preserved protein present in the nucleolus and mitochondria of mammalian cells. We have previously reported that the pro-apoptotic activity of this protein is mediated by a characteristic cysteine-rich domain. We now demonstrate that the nucleolar localization of NOA36 is due to a highly-conserved nucleolar localization signal (NoLS) present in residues 1–33. This NoLS is a sequence containing three clusters of two or three basic amino acids. We fused the amino terminal of NOA36 to eGFP in order to characterize this putative NoLS. We show that a cluster of three lysine residues at positions 3 to 5 within this sequence is critical for the nucleolar localization. We also demonstrate that the sequence as found in human is capable of directing eGFP to the nucleolus in several mammal, fish and insect cells. Moreover, this NoLS is capable of specifically directing the cytosolic yeast enzyme polyphosphatase to the target of the nucleolus of HeLa cells, wherein its enzymatic activity was detected. This NoLS could therefore serve as a very useful tool as a nucleolar marker and for directing particular proteins to the nucleolus in distant animal species. PMID:23516598

hp-HGS strategy for inverse 3D DC resistivity logging measurement simulations

KAUST Repository

Gajda-Zaǵorska, Ewa; Paszý nski, Maciej; Schaefer, Robert; Pardo, David; Calo, Victor M.

2012-01-01

In this paper we present a twin adaptive strategy hp-HGS for solving inverse problems related to 3D DC borehole resistivity measurement simulations. The term “simulation of measurements” is widely used by the geophysical community. A quantity of interest, voltage, is measured at a receiver electrode located in the logging instrument. We use the self-adaptive goal-oriented hp-Finite Element Method (hp-FEM) computer simulations of the process of measurements in deviated wells (when the angle between the borehole and formation layers are < 90 deg). We also employ the hierarchical genetic search (HGS) algorithm to solve the inverse problem. Each individual in the population represents a single configuration of the formation layers. The evaluation of the individual is performed by solving the direct problem by means of the hp-FEM algorithm and by comparison with measured logging curve. We conclude the paper with some discussion on the parallelization of the algorithm.

hp-HGS strategy for inverse 3D DC resistivity logging measurement simulations

KAUST Repository

Gajda-Zaǵorska, Ewa

2012-06-02

In this paper we present a twin adaptive strategy hp-HGS for solving inverse problems related to 3D DC borehole resistivity measurement simulations. The term “simulation of measurements” is widely used by the geophysical community. A quantity of interest, voltage, is measured at a receiver electrode located in the logging instrument. We use the self-adaptive goal-oriented hp-Finite Element Method (hp-FEM) computer simulations of the process of measurements in deviated wells (when the angle between the borehole and formation layers are < 90 deg). We also employ the hierarchical genetic search (HGS) algorithm to solve the inverse problem. Each individual in the population represents a single configuration of the formation layers. The evaluation of the individual is performed by solving the direct problem by means of the hp-FEM algorithm and by comparison with measured logging curve. We conclude the paper with some discussion on the parallelization of the algorithm.

Globular cluster seeding by primordial black hole population

Energy Technology Data Exchange (ETDEWEB)

Dolgov, A. [ITEP, Bol. Cheremushkinsaya ul., 25, 117218 Moscow (Russian Federation); Postnov, K., E-mail: dolgov@fe.infn.it, E-mail: kpostnov@gmail.com [Sternberg Astronomical Institute, Moscow M.V. Lomonosov State University, Universitetskij pr., 13, Moscow 119234 (Russian Federation)

2017-04-01

Primordial black holes (PBHs) that form in the early Universe in the modified Affleck-Dine (AD) mechanism of baryogenesis should have intrinsic log-normal mass distribution of PBHs. We show that the parameters of this distribution adjusted to provide the required spatial density of massive seeds (≥ 10{sup 4} M {sub ⊙}) for early galaxy formation and not violating the dark matter density constraints, predict the existence of the population of intermediate-mass PBHs with a number density of 0∼ 100 Mpc{sup −3}. We argue that the population of intermediate-mass AD PBHs can also seed the formation of globular clusters in galaxies. In this scenario, each globular cluster should host an intermediate-mass black hole with a mass of a few thousand solar masses, and should not obligatorily be immersed in a massive dark matter halo.

Changes in the protein profile of Habanero pepper ( Capsicum ...

African Journals Online (AJOL)

Protein profile was studied during the development of Capsicum chinense somatic embryos. The total protein content and profile of polypeptides (by sodium dodecyl sulfate polyacrylamide gel electrophoresis) of somatic embryos at different developmental stages (globular, heart-shaped, torpedo and cotyledonary stages) ...

A tensegrity model for hydrogen bond networks in proteins.

Science.gov (United States)

Bywater, Robert P

2017-05-01

Hydrogen-bonding networks in proteins considered as structural tensile elements are in balance separately from any other stabilising interactions that may be in operation. The hydrogen bond arrangement in the network is reminiscent of tensegrity structures in architecture and sculpture. Tensegrity has been discussed before in cells and tissues and in proteins. In contrast to previous work only hydrogen bonds are studied here. The other interactions within proteins are either much stronger - covalent bonds connecting the atoms in the molecular skeleton or weaker forces like the so-called hydrophobic interactions. It has been demonstrated that the latter operate independently from hydrogen bonds. Each category of interaction must, if the protein is to have a stable structure, balance out. The hypothesis here is that the entire hydrogen bond network is in balance without any compensating contributions from other types of interaction. For sidechain-sidechain, sidechain-backbone and backbone-backbone hydrogen bonds in proteins, tensegrity balance ("closure") is required over the entire length of the polypeptide chain that defines individually folding units in globular proteins ("domains") as well as within the repeating elements in fibrous proteins that consist of extended chain structures. There is no closure to be found in extended structures that do not have repeating elements. This suggests an explanation as to why globular domains, as well as the repeat units in fibrous proteins, have to have a defined number of residues. Apart from networks of sidechain-sidechain hydrogen bonds there are certain key points at which this closure is achieved in the sidechain-backbone hydrogen bonds and these are associated with demarcation points at the start or end of stretches of secondary structure. Together, these three categories of hydrogen bond achieve the closure that is necessary for the stability of globular protein domains as well as repeating elements in fibrous proteins.

The effect of polycarboxylate shell of magnetite nanoparticles on protein corona formation in blood plasma

Energy Technology Data Exchange (ETDEWEB)

Szekeres, Márta, E-mail: szekeres@chem.u-szeged.hu [Department of Physical Chemistry and Materials Sciences, University of Szeged, Hungary, 1 Aradi vt, 6720 Szeged (Hungary); Tóth, Ildikó Y. [Department of Physical Chemistry and Materials Sciences, University of Szeged, Hungary, 1 Aradi vt, 6720 Szeged (Hungary); Turcu, R. [National Institute R& D for Isotopic and Molecular Technology, Cluj-Napoca 400293 (Romania); Tombácz, Etelka [Department of Physical Chemistry and Materials Sciences, University of Szeged, Hungary, 1 Aradi vt, 6720 Szeged (Hungary)

2017-04-01

The development of protein corona around nanoparticles upon administration to the human body is responsible in a large part for their biodistribution, cell-internalization and toxicity or biocompatibility. We studied the influence of the chemical composition of polyelectrolyte shells (citric acid (CA) and poly(acrylic-co-maleic acid) (PAM)) of core-shell magnetite nanoparticles (MNPs) on the evolution of protein corona in human plasma (HP). The aggregation state and zeta potential of the particles were measured in the range of HP concentration between 1 and 80 (v/v)% 3 min and 20 h after dispersing the particles in HP diluted with Tris buffered saline. Naked MNPs aggregated in HP solution, but the carboxylated MNPs became stabilized colloidally at higher plasma concentrations. Significant differences were observed at low plasma concentration. CA@MNPs aggregated instantly while the hydrodynamic diameter of PAM@MNP increased only slightly at 1–3 v/v % HP concentrations. The observed differences in protein corona formation can be explained by the differences in the steric effects of the polycarboxylate shells. It is interesting that relatively small but systematic changes in zeta potential alter the aggregation state significantly. - Highlights: • Human plasma protein corona cannot stabilize naked and citrate-coated magnetite nanoparticles. • Polycarboxylic acid (PAM) coated MNPs are well stabilized with HP protein corona. • Stability pattern of naked, CA and PAM-coated MNPs is not predicted by zeta potential.

Effect of hypoproteinemia (HP) upon FT4 and FT3 by kinetic radioligandassay (RLA)

International Nuclear Information System (INIS)

Bottger, I.G.; Schneck, H.J.

1985-01-01

HP, especially hypoalbuminemia (HA), has been associated with false low FT4 by RLA, predominantly of the analogue tracer type. Based upon previous more favourable findings in severe nonthyroidal illness (NTI), this study was designed to study this problem in more detail. Two groups of patients with severe NTI (polytrauma) were selected on the basis of their total serum protein (TSP) concentration and studied during intensive-care. Group I: N = 25, TSP 5.9 g/dl (6.0 - 7.7), A/G: 1.5, sera: N = 76. I and II: low-dose heparin (i.v. 5000 U/24 h), non-detectable in the periphery. The RLA kits used were: FT4/T4 and FT3/T3 (kinetic two-tube), and TBG, Corning Medical, rT3, Serono, TSH, Henning-Berlin, TSP/electrophoresis standard technique. The findings indicate: 1. Typical findings for follow-up of severe NTI; 2. No detection of a significant effect of HP/HA upon these RLAs for FT4 and FT3; and 3. The inter-group differences are most likely due to more severe NT1 in I (R/sub x/, A/G, rT3)

Synthesis gas generation by high pressure partial oxidation (HP POX {sup registered}); Synthesegaserzeugung durch Hochdruck-Partialoxidation (HP POX {sup registered})

Energy Technology Data Exchange (ETDEWEB)

Meyer, B.; Seifert, P.; Zeissler, R. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Energieverfahrenstechnik und Chemieingenieurwesen; Walter, St. [Lurgi AG, Frankfurt/Main (Germany)

2005-05-01

The high pressure synthesis gas process HP POX (High Pressure Partial Oxidation) is a thermal conversion process, which converts e.g. natural gas or heavy residue oil with oxygen to fuel or synthesis gas. Innovative burner technologies allow autothermal catalytic or non-catalytic reforming of gaseous feedstock and gasification of liquid feed streams. Hydrogen and carbon monoxide rich synthesis gases with low methane content (particularly suitable as feed gas for methanol synthesis) can be generated. The technology represents a new generation of entrained flow gasification characterized by the new developed equipment and a design pressure of 100 bar. According to the feeds, the HP POX gasification process is the link between the downstream synthesis chemistry (use of gaseous and liquid feeds) and the power plant process (liquid or solid fuels as suspension or slurry). The HP POX development is carried out together with the Lurgi AG at the Institute for Energy Process Engineering and Chemical Engineering (IEC). The 5 MW HP POX test plant built in Freiberg by Lurgi is core of the joint research project, which is supported by the German Federal Ministry of Economics and Labour (BMWA), the Saxon Ministry of Science and the Fine Arts (SMWK), and the mg technologies ag (parent company of Lurgi). The conducted sets of experiments indicate that the unit can be operated in a safe, smooth and stable manner. During this periods of operation, which included nine test campaigns for autothermal reforming (ATR), the maximum pressure for ATR amounted to 70 bar which exceeds the current benchmark in industry for 30 bar. Main objective of R and D work is the development of modelling tools for extreme gasification conditions and different gasification principles of up to 100 bar. These tools are supposed to improve the understanding of the entire gasification process. Their development requires a systematic investigation of the reaction mechanisms and the interactions with the process

Globular adiponectin controls insulin-mediated vasoreactivity in muscle through AMPKα2

DEFF Research Database (Denmark)

de Boer, Michiel P; Meijer, Rick I; Richter, Erik

2016-01-01

Decreased tissue perfusion increases the risk of developing insulin resistance and cardiovascular disease in obesity, and decreased levels of globular adiponectin (gAdn) have been proposed to contribute to this risk. We hypothesized that gAdn controls insulin's vasoactive effects through AMP......-activated protein kinase (AMPK), specifically its α2 subunit, and studied the mechanisms involved. In healthy volunteers, we found that decreased plasma gAdn levels in obese subjects associate with insulin resistance and reduced capillary perfusion during hyperinsulinemia. In cultured human microvascular...... endothelial cells (HMEC), gAdn increased AMPK activity. In isolated muscle resistance arteries gAdn uncovered insulin-induced vasodilation by selectively inhibiting insulin-induced activation of ERK1/2, and the AMPK inhibitor compound C as well as genetic deletion of AMPKα2 blunted insulin...

New bound on neutrino dipole moments from globular-cluster stars

Science.gov (United States)

Raffelt, Georg G.

1990-01-01

Neutrino dipole moments mu(nu) would increase the core mass of red giants at the helium flash by delta(Mc) = 0.015 solar mass x mu(nu)/10 to the -12th muB (where muB is the Bohr magneton) because of enhanced neutrino losses. Existing measurements of the bolometric magnitudes of the brightest red giants in 26 globular clusters, number counts of horizontal-branch stars and red giants in 15 globular clusters, and statistical parallax determinations of field RR Lyr luminosities yield delta(Mc) = 0.009 + or - 0.012 solar mass, so that conservatively mu(nu) is less than 3 x 10 to the -12th muB.

A potential role for Helicobacter pylori heat shock protein 60 in gastric tumorigenesis

Energy Technology Data Exchange (ETDEWEB)

Lin, Chen-Si [Department of Biological Science and Technology, National Chiao-Tung University, Hsin-Chu, Taiwan (China); School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan (China); He, Pei-Juin [Department of Biological Science and Technology, National Chiao-Tung University, Hsin-Chu, Taiwan (China); Tsai, Nu-Man [School of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung, Taiwan (China); Li, Chi-Han; Yang, Shang-Chih; Hsu, Wei-Tung [Department of Biological Science and Technology, National Chiao-Tung University, Hsin-Chu, Taiwan (China); Wu, Ming-Shiang [Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Wu, Chang-Jer [Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan (China); Cheng, Tain-Lu [Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Liao, Kuang-Wen, E-mail: kitchhen@yahoo.com.tw [Department of Biological Science and Technology, National Chiao-Tung University, Hsin-Chu, Taiwan (China)

2010-02-05

Helicobacter pylori has been found to promote the malignant process leading to gastric cancer. Heat shock protein 60 of H. pylori (HpHSP60) was previously been identified as a potent immunogene. This study investigates the role of HpHSP60 in gastric cancer carcinogenesis. The effect of HpHSP60 on cell proliferation, anti-death activity, angiogenesis and cell migration were explored. The results showed that HpHSP60 enhanced migration by gastric cancer cells and promoted tube formation by umbilical vein endothelial cells (HUVECs); however, HpHSP60 did not increase cell proliferation nor was this protein able to rescue gastric cancer cells from death. Moreover, the results also indicated HpHSP60 had different effects on AGS gastric cancer cells or THP-1 monocytic cells in terms of their expression of pro-inflammatory cytokines, which are known to be important to cancer development. We propose that HpHSP60 may trigger the initiation of carcinogenesis by inducing pro-inflammatory cytokine release and by promoting angiogenesis and metastasis. Thus, this extracellular pathogen-derived HSP60 is potentially a vigorous virulence factor that can act as a carcinogen during gastric tumorigenesis.

Acute Phase Proteins and Variables of Protein Metabolism in Dairy Cows during the Pre- and Postpartal Period

Directory of Open Access Journals (Sweden)

Cs. Tóthová

2008-01-01

Full Text Available The objective of the present study was to compare the concentrations of acute phase proteins and selected variables of protein metabolism in dairy cows of the Slovak Spotted breed from 4 weeks before parturition to 10 weeks after parturition. Acute phase proteins - haptoglobin (Hp and serum amyloid A (SAA - and variables of protein metabolism - total proteins, albumin, urea, creatinine, total immunoglobulins - were evaluated in blood serum. Significant differences were found in average values of the Hp and SAA concentrations in several groups during the monitored period (P P P P P P P P P < 0.001. The above mentioned results indicate that in the time around parturition there are significant changes in concentrations of acute phase proteins, as well as in the whole protein metabolism of dairy cows. These facts suggest that the postparturient period is a critical biological phase, throughout which there is the highest incidence of metabolic disorders.

Intrauterine growth retarded progeny of pregnant sows fed high protein:low carbohydrate diet is related to metabolic energy deficit.

Directory of Open Access Journals (Sweden)

Cornelia C Metges

Full Text Available High and low protein diets fed to pregnant adolescent sows led to intrauterine growth retardation (IUGR. To explore underlying mechanisms, sow plasma metabolite and hormone concentrations were analyzed during different pregnancy stages and correlated with litter weight (LW at birth, sow body weight and back fat thickness. Sows were fed diets with low (6.5%, LP, adequate (12.1%, AP, and high (30%, HP protein levels, made isoenergetic by adjusted carbohydrate content. At -5, 24, 66, and 108 days post coitum (dpc fasted blood was collected. At 92 dpc, diurnal metabolic profiles were determined. Fasted serum urea and plasma glucagon were higher due to the HP diet. High density lipoprotein cholesterol (HDLC, %HDLC and cortisol were reduced in HP compared with AP sows. Lowest concentrations were observed for serum urea and protein, plasma insulin-like growth factor-I, low density lipoprotein cholesterol, and progesterone in LP compared with AP and HP sows. Fasted plasma glucose, insulin and leptin concentrations were unchanged. Diurnal metabolic profiles showed lower glucose in HP sows whereas non-esterified fatty acids (NEFA concentrations were higher in HP compared with AP and LP sows. In HP and LP sows, urea concentrations were 300% and 60% of AP sows, respectively. Plasma total cholesterol was higher in LP than in AP and HP sows. In AP sows, LW correlated positively with insulin and insulin/glucose and negatively with glucagon/insulin at 66 dpc, whereas in HP sows LW associated positively with NEFA. In conclusion, IUGR in sows fed high protein:low carbohydrate diet was probably due to glucose and energy deficit whereas in sows with low protein:high carbohydrate diet it was possibly a response to a deficit of indispensable amino acids which impaired lipoprotein metabolism and favored maternal lipid disposal.

MOCK OBSERVATIONS OF BLUE STRAGGLERS IN GLOBULAR CLUSTER MODELS

International Nuclear Information System (INIS)

Sills, Alison; Glebbeek, Evert; Chatterjee, Sourav; Rasio, Frederic A.

2013-01-01

We created artificial color-magnitude diagrams of Monte Carlo dynamical models of globular clusters and then used observational methods to determine the number of blue stragglers in those clusters. We compared these blue stragglers to various cluster properties, mimicking work that has been done for blue stragglers in Milky Way globular clusters to determine the dominant formation mechanism(s) of this unusual stellar population. We find that a mass-based prescription for selecting blue stragglers will select approximately twice as many blue stragglers than a selection criterion that was developed for observations of real clusters. However, the two numbers of blue stragglers are well-correlated, so either selection criterion can be used to characterize the blue straggler population of a cluster. We confirm previous results that the simplified prescription for the evolution of a collision or merger product in the BSE code overestimates their lifetimes. We show that our model blue stragglers follow similar trends with cluster properties (core mass, binary fraction, total mass, collision rate) as the true Milky Way blue stragglers as long as we restrict ourselves to model clusters with an initial binary fraction higher than 5%. We also show that, in contrast to earlier work, the number of blue stragglers in the cluster core does have a weak dependence on the collisional parameter Γ in both our models and in Milky Way globular clusters

Discovery of a ~205 Hz X-ray pulsar in the globular cluster NGC 6440

NARCIS (Netherlands)

Altamirano, D.; Strohmayer, T.E.; Heinke, C.O.; Markwardt, C.B.; Swank, J.H.; Pereira, D.; Smith, E.; Wijnands, R.; Linares, M.; Patruno, A.; Casella, P.; van der Klis, M.

2009-01-01

Discovery of a 205 Hz X-ray pulsar in the globular cluster NGC 6440 The globular cluster NGC 6440 was observed by the PCA instrument aboard RXTE on August 30, 2009 at 01:42 (UTC). The observation lasted for approximately 3000 seconds and the source was detected with an intensity of ~7 mCrab (2-10

VARIABLE STARS IN LARGE MAGELLANIC CLOUD GLOBULAR CLUSTERS. II. NGC 1786

International Nuclear Information System (INIS)

Kuehn, Charles A.; Smith, Horace A.; De Lee, Nathan; Catelan, Márcio; Pritzl, Barton J.; Borissova, Jura

2012-01-01

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series B–V photometric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is seen in most globular clusters.

A 5.75-millisecond pulsar in the globular cluster 47 Tucanae

International Nuclear Information System (INIS)

Manchester, R.N.; Lyne, A.G.; Johnston, S.; D'Amico, N.; Lim, J.; Kniffen, D.A.

1990-01-01

Millisecond pulsars are generally believed to be old pulsars that have been spun up ('recycled') as a result of accretion of matter from a companion in a low-mass X-ray binary system. As there is a high incidence of such systems in globular clusters, these are good places to search for millisecond pulsars; so far, ten globular-cluster pulsars have been detected unambiguously. Using the Parkes radiotelescope in Australia, we have found a pulsar with a period of 5.75 ms and a dispersion measure of 25 cm -3 pc in the direction of 47 Tucanae. Despite its probable origin as a member of a binary system, timing measurements show that the pulsar is now single. The observed dispersion measure is consistent with the pulsar lying outside the galactic electron layer and within 47 Tucanae; but it is very different from the value of 67 cm -3 pc for the pulsars that were reported recently as being in this globular cluster, and we suggest that the latter pulsars probably do not in fact lie within 47 Tucanae. (author)

THE SIZE DIFFERENCE BETWEEN RED AND BLUE GLOBULAR CLUSTERS IS NOT DUE TO PROJECTION EFFECTS

International Nuclear Information System (INIS)

Webb, Jeremy J.; Harris, William E.; Sills, Alison

2012-01-01

Metal-rich (red) globular clusters in massive galaxies are, on average, smaller than metal-poor (blue) globular clusters. One of the possible explanations for this phenomenon is that the two populations of clusters have different spatial distributions. We test this idea by comparing clusters observed in unusually deep, high signal-to-noise images of M87 with a simulated globular cluster population in which the red and blue clusters have different spatial distributions, matching the observations. We compare the overall distribution of cluster effective radii as well as the relationship between effective radius and galactocentric distance for both the observed and simulated red and blue sub-populations. We find that the different spatial distributions does not produce a significant size difference between the red and blue sub-populations as a whole or at a given galactocentric distance. These results suggest that the size difference between red and blue globular clusters is likely due to differences during formation or later evolution.

The Size Difference between Red and Blue Globular Clusters is not due to Projection Effects

Science.gov (United States)

Webb, Jeremy J.; Harris, William E.; Sills, Alison

2012-11-01

Metal-rich (red) globular clusters in massive galaxies are, on average, smaller than metal-poor (blue) globular clusters. One of the possible explanations for this phenomenon is that the two populations of clusters have different spatial distributions. We test this idea by comparing clusters observed in unusually deep, high signal-to-noise images of M87 with a simulated globular cluster population in which the red and blue clusters have different spatial distributions, matching the observations. We compare the overall distribution of cluster effective radii as well as the relationship between effective radius and galactocentric distance for both the observed and simulated red and blue sub-populations. We find that the different spatial distributions does not produce a significant size difference between the red and blue sub-populations as a whole or at a given galactocentric distance. These results suggest that the size difference between red and blue globular clusters is likely due to differences during formation or later evolution.

Acute phase proteins as diagnostic markers in horses with colic

DEFF Research Database (Denmark)

Pihl, Tina; Scheepers, Elrien; Sanz, Macarena

2016-01-01

Objective – To investigate the diagnostic potential of the concentrations of acute-phase proteins serum amyloid A (SAA), haptoglobin (Hp), and fibrinogen in blood and peritoneal fluid (PF) for differentiating horses within flammatory colic (entero-colitis and peritonitis) from those with surgical...... of the model to correctly differentiate inflammatory from surgical colic was 86% determined as area under the receiver operating characteristic curve. Adding blood parameters (WBC, PCV, total plasma protein, lactate, SAA, Hp, and fibrinogen concentrations) to the logistic model based on clinical parameters...... revealed that only WBC and SAA and fibrinogen concentrations improved the model. With SAA included in the model no additional blood parameters improved the model, and the final model had an area under the curve of 90%. Addition of PF parameters (hemolysis, total protein concentration, WBC, SAA, or Hp...

Effect of a high-protein breakfast on the postprandial ghrelin response

DEFF Research Database (Denmark)

Blom, Wendy A M; Lluch, Anne; Stafleu, Annette

2006-01-01

BACKGROUND: The most satiating macronutrient appears to be dietary protein. Few studies have investigated the effects of dietary protein on ghrelin secretion in humans. OBJECTIVE: This study was designed to investigate whether a high-protein (HP) breakfast is more satiating than a high-carbohydra......BACKGROUND: The most satiating macronutrient appears to be dietary protein. Few studies have investigated the effects of dietary protein on ghrelin secretion in humans. OBJECTIVE: This study was designed to investigate whether a high-protein (HP) breakfast is more satiating than a high......-carbohydrate breakfast (HC) through suppression of postprandial ghrelin concentrations or through other physiologic processes. DESIGN: Fifteen healthy men were studied in a single-blind, crossover design. Blood samples and subjective measures of satiety were assessed frequently for 3 h after the consumption of 2...... absorption test. RESULTS: The HP breakfast decreased postprandial ghrelin secretion more than did the HC breakfast (P Ghrelin concentrations were correlated with glucose-dependent insulinotropic polypeptide (r = -0.65; 95% CI: -0.85, -0.29) and glucagon concentrations (r = -0.47; 95% CI: -0.75, -0...

Clerget 100 hp heavy-oil engine

Science.gov (United States)

Leglise, Pierre

1931-01-01

A complete technical description of the Clerget heavy-oil engine is presented along with the general characteristics. The general characteristics are: 9 cylinders, bore 120 mm, stroke 130 mm, four-stroke cycle engine, rated power limited to 100 hp at 1800 rpm; weight 228 kg; propeller with direct drive and air cooling. Moving parts, engine block, and lubrication are all presented.

NGC 6273: Towards Defining A New Class of Galactic Globular Clusters?

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Johnson, Christian I.; Rich, Robert Michael; Pilachowski, Catherine A.; Caldwell, Nelson; Mateo, Mario L.; Ira Bailey, John; Crane, Jeffrey D.

2016-01-01

A growing number of observations have found that several Galactic globular clusters exhibit abundance dispersions beyond the well-known light element (anti-)correlations. These clusters tend to be very massive, have >0.1 dex intrinsic metallicity dispersions, have complex sub-giant branch morphologies, and have correlated [Fe/H] and s-process element enhancements. Interestingly, nearly all of these clusters discovered so far have [Fe/H]~-1.7. In this context, we have examined the chemical composition of 18 red giant branch (RGB) stars in the massive, metal-poor Galactic bulge globular cluster NGC 6273 using high signal-to-noise, high resolution (R~27,000) spectra obtained with the Michigan/Magellan Fiber System (M2FS) and MSpec spectrograph mounted on the Magellan-Clay 6.5m telescope at Las Campanas Observatory. We find that the cluster exhibits a metallicity range from [Fe/H]=-1.80 to -1.30 and is composed of two dominant populations separated in [Fe/H] and [La/Fe] abundance. The increase in [La/Eu] as a function of [La/H] suggests that the increase in [La/Fe] with [Fe/H] is due to almost pure s-process enrichment. The most metal-rich star in our sample is not strongly La-enhanced, but is α-poor and may belong to a third "anomalous" stellar population. The two dominant populations exhibit the same [Na/Fe]-[Al/Fe] correlation found in other "normal" globular clusters. Therefore, NGC 6273 joins ω Centauri, M 22, M 2, and NGC 5286 as a possible new class of Galactic globular clusters.

Immunomodulatory effects of high-protein diet with resveratrol supplementation on radiation-induced acute-phase inflammation in rats.

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Kim, Kyoung-Ok; Park, HyunJin; Chun, Mison; Kim, Hyun-Sook

2014-09-01

We hypothesized that a high-protein diet and/or resveratrol supplementation will improve acute inflammatory responses in rats after receiving experimental abdominal radiation treatment (ART). Based on our previous study, the period of 10 days after ART was used as an acute inflammation model. Rats were exposed to a radiation dose of 17.5 Gy and were supplied with a control (C), 30% high-protein diet (HP), resveratrol supplementation (RES), or HP with RES diet ([HP+RES]). At day 10 after ART, we measured profiles of lipids, proteins, and immune cells in blood. The levels of clusters of differentiating 4(+) (CD4(+)) cells and regulatory T cells, serum proinflammatory cytokines, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine were also measured. ART caused significant disturbances of lipid profiles by increasing triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C), and decreasing high-density lipoprotein cholesterol. The proinflammatroy cytokine levels were also increased by ART. All the experimental diets (HP, RES, and [HP+RES]) significantly decreased levels of TG, monocytes, proinflammatory cytokines, and 8-OHdG, whereas the platelet counts were increased. In addition, the HP and [HP+RES] diets decreased the concentrations of plasma LDL-C and total cholesterol. Also, the HP and RES diets decreased regulatory T cells compared with those of the control diet in ART group. Further, the HP diet led to a significant recovery of white blood cell counts, as well as increased percentages of lymphocyte and decreased percentages of neutrophils. In summary, RES appeared to be significantly effective in minimizing radiation-induced damage to lipid metabolism and immune responses. Our study also demonstrated the importance of dietary protein intake in recovering from acute inflammation by radiation.

[Interconnection between architecture of protein globule and disposition of conformational conservative oligopeptides in proteins from one protein family].

Science.gov (United States)

Batianovskiĭ, A V; Filatov, I V; Namiot, V A; Esipova, N G; Volotovskiĭ, I D

2012-01-01

It was shown that selective interactions between helical segments of macromolecules can realize in globular proteins in the segments characterized by the same periodicities of charge distribution i.e. between conformationally conservative oligopeptides. It was found that in the macromolecules of alpha-helical proteins conformationally conservative oligopeptides are disposed at a distance being characteristic of direct interactions. For representatives of many structural families of alpha-type proteins specific disposition of conformationally conservative segments is observed. This disposition is inherent to a particular structural family. Disposition of conformationally conservative segments is not related to homology of the amino acid sequence but reflects peculiarities of native 3D-architectures of protein globules.

Trypanosoma brucei gambiense group 1 is distinguished by a unique amino acid substitution in the HpHb receptor implicated in human serum resistance.

Directory of Open Access Journals (Sweden)

Rebecca E Symula

Full Text Available Trypanosoma brucei rhodesiense (Tbr and T. b. gambiense (Tbg, causative agents of Human African Trypanosomiasis (sleeping sickness in Africa, have evolved alternative mechanisms of resisting the activity of trypanosome lytic factors (TLFs, components of innate immunity in human serum that protect against infection by other African trypanosomes. In Tbr, lytic activity is suppressed by the Tbr-specific serum-resistance associated (SRA protein. The mechanism in Tbg is less well understood but has been hypothesized to involve altered activity and expression of haptoglobin haemoglobin receptor (HpHbR. HpHbR has been shown to facilitate internalization of TLF-1 in T.b. brucei (Tbb, a member of the T. brucei species complex that is susceptible to human serum. By evaluating the genetic variability of HpHbR in a comprehensive geographical and taxonomic context, we show that a single substitution that replaces leucine with serine at position 210 is conserved in the most widespread form of Tbg (Tbg group 1 and not found in related taxa, which are either human serum susceptible (Tbb or known to resist lysis via an alternative mechanism (Tbr and Tbg group 2. We hypothesize that this single substitution contributes to reduced uptake of TLF and thus may play a key role in conferring serum resistance to Tbg group 1. In contrast, similarity in HpHbR sequence among isolates of Tbg group 2 and Tbb/Tbr provides further evidence that human serum resistance in Tbg group 2 is likely independent of HpHbR function.

Meals based on vegetable protein sources (beans and peas) are more satiating than meals based on animal protein sources (veal and pork) – a randomized cross-over meal test study

Science.gov (United States)

Kristensen, Marlene D.; Bendsen, Nathalie T.; Christensen, Sheena M.; Astrup, Arne; Raben, Anne

2016-01-01

Background Recent nutrition recommendations advocate a reduction in protein from animal sources (pork, beef) because of environmental concerns. Instead, protein from vegetable sources (beans, peas) should be increased. However, little is known about the effect of these vegetable protein sources on appetite regulation. Objective To examine whether meals based on vegetable protein sources (beans/peas) are comparable to meals based on animal protein sources (veal/pork) regarding meal-induced appetite sensations. Design In total, 43 healthy, normal-weight, young men completed this randomized, double-blind, placebo-controlled, three-way, cross-over meal test. The meals (all 3.5 MJ, 28 energy-% (E%) fat) were either high protein based on veal and pork meat, HP-Meat (19 E% protein, 53 E% carbohydrate, 6 g fiber/100 g); high protein based on legumes (beans and peas), HP-Legume (19 E% protein, 53 E% carbohydrate, 25 g fiber/100 g); or low-protein based on legumes, LP-Legume (9 E% protein, 62 E% carbohydrate, 10 g fiber/100 g). Subjective appetite sensations were recorded at baseline and every half hour using visual analog scales until the ad libitum meal 3 h after the test meal. Repeated measurements analyses and summary analyses were performed using ANCOVA (SAS). Results HP-Legume induced lower composite appetite score, hunger, prospective food consumption, and higher fullness compared to HP-Meat and LP-Legume (ppeas) influenced appetite sensations favorably compared to animal-based meals (pork/veal) with similar energy and protein content, but lower fiber content. Interestingly, a vegetable-based meal with low protein content was as satiating and palatable as an animal-based meal with high protein content. PMID:27765144

Protein conformational transitions at the liquid-gas interface as studied by dilational surface rheology.

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Noskov, Boris A

2014-04-01

Experimental results on the dynamic dilational surface elasticity of protein solutions are analyzed and compared. Short reviews of the protein behavior at the liquid-gas interface and the dilational surface rheology precede the main sections of this work. The kinetic dependencies of the surface elasticity differ strongly for the solutions of globular and non-globular proteins. In the latter case these dependencies are similar to those for solutions of non-ionic amphiphilic polymers and have local maxima corresponding to the formation of the distal region of the surface layer (type I). In the former case the dynamic surface elasticity is much higher (>60 mN/m) and the kinetic dependencies are monotonical and similar to the data for aqueous dispersions of solid nanoparticles (type II). The addition of strong denaturants to solutions of bovine serum albumin and β-lactoglobulin results in an abrupt transition from the type II to type I dependencies if the denaturant concentration exceeds a certain critical value. These results give a strong argument in favor of the preservation of the protein globular structure in the course of adsorption without any denaturants. The addition of cationic surfactants also can lead to the non-monotonical kinetic dependencies of the dynamic surface elasticity indicating destruction of the protein tertiary and secondary structures. The addition of anionic surfactants gives similar results only for the protein solutions of high ionic strength. The influence of cationic surfactants on the local maxima of the kinetic dependencies of the dynamic surface elasticity for solutions of a non-globular protein (β-casein) differs from the influence of anionic surfactants due to the heterogeneity of the charge distribution along the protein chain. In this case one can use small admixtures of ionic surfactants as probes of the adsorption mechanism. The effect of polyelectrolytes on the kinetic dependencies of the dynamic surface elasticity of protein

Edades relativas de cúmulos globulares

Science.gov (United States)

Miller Bertolami, M.; Forte, J. C.

El trabajo de Rossemberg et al (1999), estudia las edades relativas de cúmulos globulares galácticos mediante el análisis de ciertos parámetros morfológicos de los diagramas color-magnitud de dichos cúmulos. Este trabajo se centra en tres puntos: analizar la consistencia de los resultados obtenidos por Rossemberg et al (1999) al emplear observaciones en el sistema fotométrico de Washington, más precisamente, las magnitudes C y T1 en lugar de las magnitudes V e I utilizadas por dichos autores. De la existencia de colores integrados, metalicidad y edad (relativa) para 21 de los cúmulos utilizados en dicho trabajo, se analiza la consistencia de estos resultados con las dependencias de color integrado como función de la edad y la metalicidad que se desprenden de los modelos teóricos de luz integrada por Worthey (1994), Schulz (2002) y Lee et al (2002). Por último se lleva a cabo una breve comparación de la morfología de los diagramas color-magnitud de los cúmulos globulares y de las isocronas utilizadas, a fin de intentar identificar algunas de las posibles causas de las diferencias observadas en los incisos anteriores.

Theoretical stellar luminosity functions and globular cluster ages and compositions

International Nuclear Information System (INIS)

Ratcliff, S.J.

1985-01-01

The ages and chemical compositions of the stars in globular clusters are of great interest, particularly because age estimates from the well-known exercise of fitting observed color-magnitude diagrams to theoretical predictions tend to yield ages in excess of the Hubble time (an estimate to the age of the Universe) in standard cosmological models, for currently proposed high values of Hubble's constant (VandenBerg 1983). Relatively little use has been made of stellar luminosity functions of the globular clusters, for which reliable observations are now becoming available, to constrain the ages or compositions. The comparison of observed luminosity functions to theoretical ones allows one to take advantage of information not usually used, and has the advantage of being relatively insensitive to our lack of knowledge of the detailed structure of stellar envelopes and atmospheres. A computer program was developed to apply standard stellar evolutionary theory, using the most recently available input physics (opacities, nuclear reaction rates), to the calculation of the evolution of low-mass Population II stars. An algorithm for computing luminosity functions from the evolutionary tracks was applied to sets of tracks covering a broad range of chemical compositions and ages, such as may be expected for globular clusters

The Grasso 5HP as a heat pump compressor for a dairy industry; De Grasso 5HP als warmtepompcompressor voor melkfabriek

Energy Technology Data Exchange (ETDEWEB)

Vermeer, H.; Gerritsen, J.; Unsworth, R. [Gea Grenco, Den Bosch (Netherlands)

2011-12-15

GEA Refrigeration has supplied a new cooling system with an additional stage heat pump to the milk factory Robert Wiseman for the pasteurisation of milk. The required condensation temperature of the additional stage heat pump is around 80C. The Grasso 5HP reciprocating compressor has a favorable energy consumption and can be used for this application. The limitation of this compressor, however, sets requirements to the design of the installation. [Dutch] Gea Refrigeration heeft een nieuwe koelinstallatie met extratrapwarmtepomp geleverd aan zuivelbedrijf Robert Wiseman ten behoeve van pasteuriseren van melk. De hiervoor benodigde condensatietemperatuur van de extratrapwarmtepomp bedraagt ongeveer 80C. De Grasso 5HP hogedrukzuigercompressor heeft een gunstig energiegebruik en kan voor deze toepassing ingezet worden. De begrenzing van het toepassingsgebied van deze compressor stelt echter eisen aan het ontwerp van de installatie.

Quantification of Protein Biomarker Using SERS Nano-Stress Sensing with Peak Intensity Ratiometry

Science.gov (United States)

Goh, Douglas; Kong, Kien Voon; Jayakumar, Perumal; Gong, Tianxun; Dinish, U. S.; Olivo, Malini

We report a surface enhanced Raman spectroscopy (SERS) ratiometry method based on peak intensity coupled in a nano-stress sensing platform to detect and quantify biological molecules. Herein, we employed an antibody-conjugated p-aminothiophenol (ATP) functionalized on a bimetallic-film-over-nanosphere (BMFON) substrate as a sensitive SERS platform to detect human haptoglobin (Hp) protein, which is an acute phase protein and a biomarker for various cancers. Correlation between change in the ATP spectral characteristics and concentration of Hp protein was established by examining the peak intensity ratio at 1572cm-1 and 1592cm-1 that reflects the degree of stress experienced by the aromatic ring of ATP during Hp protein-antibody interaction. Development of this platform shows the potential in developing a low-cost and sensitive SERS sensor for the pre-screening of various biomarkers.

The Observational and Theoretical Tidal Radii of Globular Clusters in M87

Science.gov (United States)

Webb, Jeremy J.; Sills, Alison; Harris, William E.

2012-02-01

Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the globular cluster population of the Virgo giant M87. Unusually deep, high signal-to-noise images of M87 are used to measure the effective and limiting radii of approximately 2000 globular clusters. To compare with these observations, we simulate a globular cluster population that has the same characteristics as the observed M87 cluster population. Placing these simulated clusters in the well-studied tidal field of M87, the orbit of each cluster is solved and the theoretical tidal radius of each cluster is determined. We compare the predicted relationship between cluster size and projected galactocentric distance to observations. We find that for an isotropic distribution of cluster velocities, theoretical tidal radii are approximately equal to observed limiting radii for R gc < 10 kpc. However, the isotropic simulation predicts a steep increase in cluster size at larger radii, which is not observed in large galaxies beyond the Milky Way. To minimize the discrepancy between theory and observations, we explore the effects of orbital anisotropy on cluster sizes, and suggest a possible orbital anisotropy profile for M87 which yields a better match between theory and observations. Finally, we suggest future studies which will establish a stronger link between theoretical tidal radii and observed radii.

THE OBSERVATIONAL AND THEORETICAL TIDAL RADII OF GLOBULAR CLUSTERS IN M87

International Nuclear Information System (INIS)

Webb, Jeremy J.; Sills, Alison; Harris, William E.

2012-01-01

Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the globular cluster population of the Virgo giant M87. Unusually deep, high signal-to-noise images of M87 are used to measure the effective and limiting radii of approximately 2000 globular clusters. To compare with these observations, we simulate a globular cluster population that has the same characteristics as the observed M87 cluster population. Placing these simulated clusters in the well-studied tidal field of M87, the orbit of each cluster is solved and the theoretical tidal radius of each cluster is determined. We compare the predicted relationship between cluster size and projected galactocentric distance to observations. We find that for an isotropic distribution of cluster velocities, theoretical tidal radii are approximately equal to observed limiting radii for R gc < 10 kpc. However, the isotropic simulation predicts a steep increase in cluster size at larger radii, which is not observed in large galaxies beyond the Milky Way. To minimize the discrepancy between theory and observations, we explore the effects of orbital anisotropy on cluster sizes, and suggest a possible orbital anisotropy profile for M87 which yields a better match between theory and observations. Finally, we suggest future studies which will establish a stronger link between theoretical tidal radii and observed radii.

A controlled trial of protein enrichment of meal replacements for weight reduction with retention of lean body mass

Directory of Open Access Journals (Sweden)

Bowerman Susan

2008-08-01

Full Text Available Abstract Background While high protein diets have been shown to improve satiety and retention of lean body mass (LBM, this study was designed to determine effects of a protein-enriched meal replacement (MR on weight loss and LBM retention by comparison to an isocaloric carbohydrate-enriched MR within customized diet plans utilizing MR to achieve high protein or standard protein intakes. Methods Single blind, placebo-controlled, randomized outpatient weight loss trial in 100 obese men and women comparing two isocaloric meal plans utilizing a standard MR to which was added supplementary protein or carbohydrate powder. MR was used twice daily (one meal, one snack. One additional meal was included in the meal plan designed to achieve individualized protein intakes of either 1 2.2 g protein/kg of LBM per day [high protein diet (HP] or 2 1.1 g protein/kg LBM/day standard protein diet (SP. LBM was determined using bioelectrical impedance analysis (BIA. Body weight, body composition, and lipid profiles were measured at baseline and 12 weeks. Results Eighty-five subjects completed the study. Both HP and SP MR were well tolerated, with no adverse effects. There were no differences in weight loss at 12 weeks (-4.19 ± 0.5 kg for HP group and -3.72 ± 0.7 kg for SP group, p > 0.1. Subjects in the HP group lost significantly more fat weight than the SP group (HP = -1.65 ± 0.63 kg; SP = -0.64 ± 0.79 kg, P = 0.05 as estimated by BIA. There were no significant differences in lipids nor fasting blood glucose between groups, but within the HP group a significant decrease in cholesterol and LDL cholesterol was noted at 12 weeks. This was not seen in the SP group. Conclusion Higher protein MR within a higher protein diet resulted in similar overall weight loss as the standard protein MR plan over 12 weeks. However, there was significantly more fat loss in the HP group but no significant difference in lean body mass. In this trial, subject compliance with both the

Goal-Oriented Self-Adaptive hp Finite Element Simulation of 3D DC Borehole Resistivity Simulations

KAUST Repository

Calo, Victor M.

2011-05-14

In this paper we present a goal-oriented self-adaptive hp Finite Element Method (hp-FEM) with shared data structures and a parallel multi-frontal direct solver. The algorithm automatically generates (without any user interaction) a sequence of meshes delivering exponential convergence of a prescribed quantity of interest with respect to the number of degrees of freedom. The sequence of meshes is generated from a given initial mesh, by performing h (breaking elements into smaller elements), p (adjusting polynomial orders of approximation) or hp (both) refinements on the finite elements. The new parallel implementation utilizes a computational mesh shared between multiple processors. All computational algorithms, including automatic hp goal-oriented adaptivity and the solver work fully in parallel. We describe the parallel self-adaptive hp-FEM algorithm with shared computational domain, as well as its efficiency measurements. We apply the methodology described to the three-dimensional simulation of the borehole resistivity measurement of direct current through casing in the presence of invasion.

Short-term X-ray variability of the globular cluster source 4U 1820 - 30 (NGC 6624)

Science.gov (United States)

Stella, L.; Kahn, S. M.; Grindlay, J. E.

1984-01-01

Analytical techniques for improved identification of the temporal and spectral variability properties of globular cluster and galactic bulge X-ray sources are described in terms of their application to a large set of observations of the source 4U 1820 - 30 in the globular cluster NGC 6624. The autocorrelation function, cross-correlations, time skewness function, erratic periodicities, and pulse trains are examined. The results are discussed in terms of current models with particular emphasis on recent accretion disk models. It is concluded that the analyzed observations provide the first evidence for shot-noise variability in a globular cluster X-ray source.

Tidal stripping stellar substructures around four metal-poor globular clusters in the galactic bulge

International Nuclear Information System (INIS)

Chun, Sang-Hyun; Kang, Minhee; Jung, DooSeok; Sohn, Young-Jong

2015-01-01

We investigate the spatial density configuration of stars around four metal-poor globular clusters (NGC 6266, NGC 6626, NGC 6642, and NGC 6723) in the Galactic bulge region using wide-field deep J, H, and K imaging data obtained with the Wide Field Camera near-infrared array on the United Kingdom Infrared Telescope. A statistical weighted filtering algorithm for the stars on the color–magnitude diagram is applied in order to sort cluster member candidates from the field star contamination. In two-dimensional isodensity contour maps of the clusters, we find that all four of the globular clusters exhibit strong evidence of tidally stripped stellar features beyond the tidal radius in the form of tidal tails or small density lobes/chunks. The orientations of the extended stellar substructures are likely to be associated with the effect of dynamic interaction with the Galaxy and the cluster's space motion. The observed radial density profiles of the four globular clusters also describe the extended substructures; they depart from theoretical King and Wilson models and have an overdensity feature with a break in the slope of the profile at the outer region of clusters. The observed results could imply that four globular clusters in the Galactic bulge region have experienced strong environmental effects such as tidal forces or bulge/disk shocks of the Galaxy during the dynamical evolution of globular clusters. These observational results provide further details which add to our understanding of the evolution of clusters in the Galactic bulge region as well as the formation of the Galaxy.

Effect of short-term vs. long-term elevation of dietary protein intake on responsiveness of rat thick ascending limbs to peptide hormones.

Science.gov (United States)

Goldstein, David L; Plaga, Kimberly

2002-10-01

We compared the renal responses of rats on three diet regimens. Rats received either 8% protein food (low-protein, LP) for 10 weeks following weaning, 8% protein for 9 weeks followed by 1 week on 30% protein (short-term high-protein, SHP), or 30% protein for 10 weeks (high-protein, HP). Kidneys from HP rats were enlarged by approximately 50%, or 20% when corrected for body mass. Most of this hypertrophy resulted from enlargement of the inner stripe of the outer medulla, site of the thick ascending limbs (TAL), and TAL from HP rats were larger in diameter. SHP rats had TAL diameters similar to HP rats, but changes in renal mass or height of renal zones did not reach statistical significance. The activity of adenylyl cyclase (AC) in TAL, measured from the accumulation of cAMP in isolated tubules, increased with dose of both arginine vasopressin (AVP) and glucagon in all rats. However, HP rats had significantly higher hormone-induced AC activity than LP or SHP rats, which were not different from each other. Our results suggest that tubule hypertrophy may precede up-regulation of hormone-sensitive AC activity during the progression of renal response to elevated dietary protein.

Helicobacter pylori Outer Membrane Protein 18 (Hp1125 Is Involved in Persistent Colonization by Evading Interferon-γ Signaling

Directory of Open Access Journals (Sweden)

Yuqun Shan

2015-01-01

Full Text Available Outer membrane proteins (OMPs can induce an immune response. Omp18 (HP1125 of H. pylori is a powerful antigen that can induce significant interferon-γ (IFN-γ levels. Previous studies have suggested that IFN-γ plays an important role in H. pylori clearance. However, H. pylori has multiple mechanisms to avoid host immune surveillance for persistent colonization. We generated an omp18 mutant (H. pylori 26695 and H. pylori SS1 strain to examine whether Omp18 interacts with IFN-γ and is involved in H. pylori colonization. qRT-PCR revealed that IFN-γ induced Omp18 expression. qRT-PCR and western blot analysis revealed reduced expressions of virulence factors CagA and NapA in H. pylori 26695 with IFN-γ treatment, but they were induced in the Δomp18 strain. In C57BL/6 mice infected with H. pylori SS1 and the Δomp18 strain, the Δomp18 strain conferred defective colonization and activated a stronger inflammatory response. Signal transducer phosphorylation and transcription 1 (STAT1 activator was downregulated by the wild-type strain but not the Δomp18 strain in IFN-γ-treated macrophages. Furthermore, Δomp18 strain survival rates were poor in macrophages compared to the wild-type strain. We concluded that H. pylori Omp18 has an important function influencing IFN-γ-mediated immune response to participate in persistent colonization.

New approach to calculate the true-coincidence effect of HpGe detector

Energy Technology Data Exchange (ETDEWEB)

Alnour, I. A., E-mail: aaibrahim3@live.utm.my, E-mail: ibrahim.elnour@yahoo.com [Department of Physics, Faculty of Pure and Applied Science, International University of Africa, 12223 Khartoum (Sudan); Wagiran, H. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai,Johor (Malaysia); Ibrahim, N. [Faculty of Defence Science and Technology, National Defence University of Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia); Hamzah, S.; Elias, M. S. [Malaysia Nuclear Agency (MNA), Bangi, 43000 Kajang, Selangor D.E. (Malaysia); Siong, W. B. [Chemistry Department, Faculty of Resource Science & Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak (Malaysia)

2016-01-22

The corrections for true-coincidence effects in HpGe detector are important, especially at low source-to-detector distances. This work established an approach to calculate the true-coincidence effects experimentally for HpGe detectors of type Canberra GC3018 and Ortec GEM25-76-XLB-C, which are in operation at neutron activation analysis lab in Malaysian Nuclear Agency (NM). The correction for true-coincidence effects was performed close to detector at distances 2 and 5 cm using {sup 57}Co, {sup 60}Co, {sup 133}Ba and {sup 137}Cs as standard point sources. The correction factors were ranged between 0.93-1.10 at 2 cm and 0.97-1.00 at 5 cm for Canberra HpGe detector; whereas for Ortec HpGe detector ranged between 0.92-1.13 and 0.95-100 at 2 and 5 cm respectively. The change in efficiency calibration curve of the detector at 2 and 5 cm after correction was found to be less than 1%. Moreover, the polynomial parameters functions were simulated through a computer program, MATLAB in order to find an accurate fit to the experimental data points.

Identification of a 48 kDa tubulin or tubulin-like C6/36 mosquito cells protein that binds dengue virus 2 using mass spectrometry

International Nuclear Information System (INIS)

Chee, H.-Y.; AbuBakar, Sazaly

2004-01-01

Binding of dengue virus 2 (DENV-2) to C6/36 mosquito cells protein was investigated. A 48 kDa DENV-2-binding C6/36 cells protein (D2BP) was detected in a virus overlay protein-binding assay. The binding occurred only to the C6/36 cells cytosolic protein fraction and it was inhibited by free D2BP. D2BP was shown to bind to DENV-2 E in the far-Western-binding studies and using mass spectrometry (MS) and MS/MS, peptide masses of the D2BP that matched to β-tubulin and α-tubulin chains were identified. These findings suggest that DENV-2 through DENV-2 E binds directly to a 48 kDa tubulin or tubulin-like protein of C6/36 mosquito cells

Testing modified gravity with globular clusters: the case of NGC 2419

Science.gov (United States)

Llinares, Claudio

2018-05-01

The dynamics of globular clusters has been studied in great detail in the context of general relativity as well as with modifications of gravity that strongly depart from the standard paradigm such as Modified Newtonian Dynamics. However, at present there are no studies that aim to test the impact that less extreme modifications of gravity (e.g. models constructed as alternatives to dark energy) have on the behaviour of globular clusters. This Letter presents fits to the velocity dispersion profile of the cluster NGC 2419 under the symmetron-modified gravity model. The data show an increase in the velocity dispersion towards the centre of the cluster which could be difficult to explain within general relativity. By finding the best-fitting solution associated with the symmetron model, we show that this tension does not exist in modified gravity. However, the best-fitting parameters give a model that is inconsistent with the dynamics of the Solar system. Exploration of different screening mechanisms should give us the chance to understand if it is possible to maintain the appealing properties of the symmetron model when it comes to globular clusters and at the same time recover the Solar system dynamics properly.

Syntheses of nucleic acid and protein in somatic embryos of Fritillaria ussuriensis maxim in different development stages

International Nuclear Information System (INIS)

Wang Shuyu; Tang Wei; Wang Hui

1993-09-01

After developing a procedure for somatic embryogenesis in Fritillaria ussuriensis, dynamics on the syntheses of DNA, RNA, and protein during globular, heart-shaped, torpedo-shaped, cotyledonary, and mature somatic embryo stages was demonstrated by both autoradiography and scintillation counting. The rates of syntheses of DNA, RNA, and protein gradually increase between the globular and cotyledonary somatic embryos stages. DNA, RNA, and protein synthesis rates are in peak at the cotyledonary later stage, precotyledonary stage, and cotyledonary stage, respectively. It appears that more DNA, RNA, and protein are synthesized in the cotyledonary somatic embryo stage than in other stages. All these results indicate that an increased syntheses of DNA, RNA, and protein is associated with the differentiation of embryogenic cells and organogenesis in somatic embryos

In vitro study of proteins surface activity by tritium probe

International Nuclear Information System (INIS)

Chernysheva, M.G.; Badun, G.A.

2010-01-01

A new technique for in vitro studies of biomacromolecules interactions, their adsorption at aqueous/organic liquid interfaces and distribution in the bulk of liquid/liquid systems was developed. The method includes (1) tritium labeling of biomolecules by tritium thermal activation method and (2) scintillation phase step with organic phase, which can be concerned as a model of cellular membrane. Two globular proteins lysozyme and human serum albumin tested. We have determined the conditions of tritium labeling when labeled by-products can be easy separated by means of dialysis and size-exclusion chromatography. Scintillation phase experiments were conducted for three types of organic liquids. Thus, the influences of the nature of organic phase on proteins adsorption and its distribution in the bulk of aqueous/organic liquid system were determined. It was found that proteins possess high surface activity at aqueous/organic liquid interface. Furthermore, values of hydrophobicity of globular proteins were found by the experiment. (author)

DAMT - DISTRIBUTED APPLICATION MONITOR TOOL (HP9000 VERSION)

Science.gov (United States)

Keith, B.

1994-01-01

processes. The independent processes communicate with each other via UNIX sockets through a Virtual Path router, or Switcher. The Switcher maintains a routing table showing the host of each component process of the tool, eliminating the need for each process to do so. The Central Monitor Complex provides the single application program interface (API) to the user and coordinates the activities of DAMT. The Central Monitor Complex is itself divided into independent objects that perform its functions. The component objects are the Central Monitor, the Process Locator, the Circuit Locator, and the Traffic Reporter. Each of these objects is an independent, asynchronously executing process. User requests to the tool are interpreted by the Central Monitor. The Process Locator identifies whether a named process is running on a monitored host and which host that is. The circuit between any two processes in the distributed application is identified using the Circuit Locator. The Traffic Reporter handles communication with the LAN Analyzer and accumulates traffic updates until it must send a traffic report to the user. The Remote Monitor process is replicated on each monitored host. It serves the Central Monitor Complex processes with application process information. The Remote Monitor process provides access to operating systems information about currently executing processes. It allows the Process Locator to find processes and the Circuit Locator to identify circuits between processes. It also provides lifetime information about currently monitored processes. The LAN Analyzer consists of two processes. Low-level monitoring is handled by the Sniffer. The Sniffer analyzes the raw data on a single, physical LAN. It responds to commands from the Analyzer process, which maintains the interface to the Traffic Reporter and keeps track of which circuits to monitor. DAMT is written in C-language for HP-9000 series computers running HP-UX and Sun 3 and 4 series computers running SunOS. DAMT

Enzymatic protein hydrolysates from high pressure-pretreated isolated pea proteins have better antioxidant properties than similar hydrolysates produced from heat pretreatment.

Science.gov (United States)

Girgih, Abraham T; Chao, Dongfang; Lin, Lin; He, Rong; Jung, Stephanie; Aluko, Rotimi E

2015-12-01

Isolated pea protein (IPP) dispersions (1%, w/v) were pretreated with high pressure (HP) of 200, 400, or 600 MPa for 5 min at 24 °C or high temperature (HT) for 30 min at 100 °C prior to hydrolysis with 1% (w/w) Alcalase. HP pretreatment of IPP at 400 and 600 MPa levels led to significantly (P40%) oxygen radical absorption capacity (ORAC) of hydrolysates. 2,2-Diphenyl-1-picrylhydrazyl, superoxide radical and hydroxyl radical scavenging activities of pea protein hydrolysates were also significantly (PProtein hydrolysates from HT IPP showed no ORAC, superoxide or hydroxyl scavenging activity but had significantly (Pprotein hydrolysates had weaker antioxidant properties than glutathione but overall, the HP pretreatment was superior to HT pretreatment in facilitating enzymatic release of antioxidant peptides from IPP. Copyright © 2015 Elsevier Ltd. All rights reserved.

The RNA-binding protein, ZFP36L2, influences ovulation and oocyte maturation.

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Christopher B Ball

Full Text Available ZFP36L2 protein destabilizes AU-rich element-containing transcripts and has been implicated in female fertility. In the C57BL/6NTac mouse, a mutation in Zfp36l2 that results in the decreased expression of a form of ZFP36L2 in which the 29 N-terminal amino acid residues have been deleted, ΔN-ZFP36L2, leads to fertilized eggs that arrest at the two-cell stage. Interestingly, homozygous ΔN-Zfp36l2 females in the C57BL/6NTac strain release 40% fewer eggs than the WT littermates (Ramos et al., 2004, suggesting an additional defect in ovulation and/or oocyte maturation. Curiously, the same ΔN-Zfp36l2 mutation into the SV129 strain resulted in anovulation, prompting us to investigate a potential problem in ovulation and oocyte maturation. Remarkably, only 20% of ΔN-Zfp36l2 oocytes in the 129S6/SvEvTac strain matured ex vivo, suggesting a defect on the oocyte meiotic maturation process. Treatment of ΔN-Zfp36l2 oocytes with a PKA inhibitor partially rescued the meiotic arrested oocytes. Furthermore, cAMP levels were increased in ΔN-Zfp36l2 oocytes, linking the cAMP/PKA pathway and ΔN-Zfp36l2 with meiotic arrest. Since ovulation and oocyte maturation are both triggered by LHR signaling, the downstream pathway was investigated. Adenylyl cyclase activity was increased in ΔN-Zfp36l2 ovaries only upon LH stimulation. Moreover, we discovered that ZFP36L2 interacts with the 3'UTR of LHR mRNA and that decreased expression levels of Zfp36l2 correlates with higher levels of LHR mRNA in synchronized ovaries. Furthermore, overexpression of ZFP36L2 decreases the endogenous expression of LHR mRNA in a cell line. Therefore, we propose that lack of the physiological down regulation of LHR mRNA levels by ZFP36L2 in the ovaries is associated with anovulation and oocyte meiotic arrest.

Investigation of Trimethyllysine Binding by the HP1 Chromodomain via Unnatural Amino Acid Mutagenesis.

Science.gov (United States)

Baril, Stefanie A; Koenig, Amber L; Krone, Mackenzie W; Albanese, Katherine I; He, Cyndi Qixin; Lee, Ga Young; Houk, Kendall N; Waters, Marcey L; Brustad, Eric M

2017-12-06

Trimethyllysine (Kme3) reader proteins are targets for inhibition due to their role in mediating gene expression. Although all such reader proteins bind Kme3 in an aromatic cage, the driving force for binding may differ; some readers exhibit evidence for cation-π interactions whereas others do not. We report a general unnatural amino acid mutagenesis approach to quantify the contribution of individual tyrosines to cation binding using the HP1 chromodomain as a model system. We demonstrate that two tyrosines (Y24 and Y48) bind to a Kme3-histone tail peptide via cation-π interactions, but linear free energy trends suggest they do not contribute equally to binding. X-ray structures and computational analysis suggest that the distance and degree of contact between Tyr residues and Kme3 plays an important role in tuning cation-π-mediated Kme3 recognition. Although cation-π interactions have been studied in a number of proteins, this work is the first to utilize direct binding assays, X-ray crystallography, and modeling, to pinpoint factors that influence the magnitude of the individual cation-π interactions.

Gravitational microlensing by low-mass objects in the globular cluster M22.

Science.gov (United States)

Sahu, K C; Casertano, S; Livio, M; Gilliland, R L; Panagia, N; Albrow, M D; Potter, M

2001-06-28

Gravitational microlensing offers a means of determining directly the masses of objects ranging from planets to stars, provided that the distances and motions of the lenses and sources can be determined. A globular cluster observed against the dense stellar field of the Galactic bulge presents ideal conditions for such observations because the probability of lensing is high and the distances and kinematics of the lenses and sources are well constrained. The abundance of low-mass objects in a globular cluster is of particular interest, because it may be representative of the very early stages of star formation in the Universe, and therefore indicative of the amount of dark baryonic matter in such clusters. Here we report a microlensing event associated with the globular cluster M22. We determine the mass of the lens to be 0.13(+0.03)(-0.02) solar masses. We have also detected six events that are unresolved in time. If these are also microlensing events, they imply that a non-negligible fraction of the cluster mass resides in the form of free-floating planetary-mass objects.

The Luminosity Functions of Old and Intermediate-Age Globular Clusters in NGC 3610

OpenAIRE

Whitmore, B. C.; Schweizer, F.; Kundu, A.; Miller, B. W.

2002-01-01

The WFPC2 Camera on board HST has been used to obtain high-resolution images of NGC 3610, a dynamically young elliptical galaxy. These observations supersede shorter, undithered HST observations where an intermediate-age population of globular clusters was first discovered. The new observations show the bimodal color distribution of globular clusters more clearly, with peaks at (V-I)o = 0.95 and 1.17. The luminosity function (LF) of the blue, metal-poor population of clusters in NGC 3610 turn...

A tensegrity model for hydrogen bond networks in proteins

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Robert P. Bywater

2017-05-01

Full Text Available Hydrogen-bonding networks in proteins considered as structural tensile elements are in balance separately from any other stabilising interactions that may be in operation. The hydrogen bond arrangement in the network is reminiscent of tensegrity structures in architecture and sculpture. Tensegrity has been discussed before in cells and tissues and in proteins. In contrast to previous work only hydrogen bonds are studied here. The other interactions within proteins are either much stronger − covalent bonds connecting the atoms in the molecular skeleton or weaker forces like the so-called hydrophobic interactions. It has been demonstrated that the latter operate independently from hydrogen bonds. Each category of interaction must, if the protein is to have a stable structure, balance out. The hypothesis here is that the entire hydrogen bond network is in balance without any compensating contributions from other types of interaction. For sidechain-sidechain, sidechain-backbone and backbone-backbone hydrogen bonds in proteins, tensegrity balance (“closure” is required over the entire length of the polypeptide chain that defines individually folding units in globular proteins (“domains” as well as within the repeating elements in fibrous proteins that consist of extended chain structures. There is no closure to be found in extended structures that do not have repeating elements. This suggests an explanation as to why globular domains, as well as the repeat units in fibrous proteins, have to have a defined number of residues. Apart from networks of sidechain-sidechain hydrogen bonds there are certain key points at which this closure is achieved in the sidechain-backbone hydrogen bonds and these are associated with demarcation points at the start or end of stretches of secondary structure. Together, these three categories of hydrogen bond achieve the closure that is necessary for the stability of globular protein domains as well as repeating

A stochastic finite element model for the dynamics of globular macromolecules

Science.gov (United States)

Oliver, Robin C.; Read, Daniel J.; Harlen, Oliver G.; Harris, Sarah A.

2013-04-01

We describe a novel coarse-grained simulation method for modelling the dynamics of globular macromolecules, such as proteins. The macromolecule is treated as a continuum that is subject to thermal fluctuations. The model includes a non-linear treatment of elasticity and viscosity with thermal noise that is solved using finite element analysis. We have validated the method by demonstrating that the model provides average kinetic and potential energies that are in agreement with the classical equipartition theorem and that the nodal velocities have the correct Gaussian distribution. In addition, we have performed Fourier analysis on the simulation trajectories obtained for a series of linear beams to confirm that the correct average energies are present in the first two Fourier bending modes and that the probability distribution of the amplitudes of the first two Fourier modes match the theoretical results. We demonstrate spatial convergence of the model by showing that the anisotropy of the inertia tensor for a cubic mesh converges as a function of the mesh resolution. We have then used the new modelling method to simulate the thermal fluctuations of a representative protein over 500 ns timescales. Using reasonable parameters for the material properties, we have demonstrated that the overall deformation of the biomolecule is consistent with the results obtained for proteins in general from atomistic molecular dynamics simulations.

Trazando la materia oscura con cúmulos globulares

Science.gov (United States)

Forte, J. C.

Se describe la estrategia adoptada para mapear la distribución de materia oscura y bariónica en galaxias elípticas cuyos cúmulos globulares están siendo observados con los telescopios VLT y Gemini. Se ejemplifican los resultados con los datos obtenidos en el cúmulo de Fornax.

Dating the Tidal Disruption of Globular Clusters with GAIA Data on Their Stellar Streams

Science.gov (United States)

Bose, Sownak; Ginsburg, Idan; Loeb, Abraham

2018-05-01

The Gaia mission promises to deliver precision astrometry at an unprecedented level, heralding a new era for discerning the kinematic and spatial coordinates of stars in our Galaxy. Here, we present a new technique for estimating the age of tidally disrupted globular cluster streams using the proper motions and parallaxes of tracer stars. We evolve the collisional dynamics of globular clusters within the evolving potential of a Milky Way-like halo extracted from a cosmological ΛCDM simulation and analyze the resultant streams as they would be observed by Gaia. The simulations sample a variety of globular cluster orbits, and account for stellar evolution and the gravitational influence of the disk of the Milky Way. We show that a characteristic timescale, obtained from the dispersion of the proper motions and parallaxes of stars within the stream, is a good indicator for the time elapsed since the stream has been freely expanding away due to the tidal disruption of the globular cluster. This timescale, in turn, places a lower limit on the age of the cluster. The age can be deduced from astrometry using a modest number of stars, with the error on this estimate depending on the proximity of the stream and the number of tracer stars used.

Goal-Oriented Self-Adaptive hp Finite Element Simulation of 3D DC Borehole Resistivity Simulations

KAUST Repository

Calo, Victor M.; Pardo, David; Paszyński, Maciej R.

2011-01-01

(adjusting polynomial orders of approximation) or hp (both) refinements on the finite elements. The new parallel implementation utilizes a computational mesh shared between multiple processors. All computational algorithms, including automatic hp goal

On the importance of polar interactions for complexes containing intrinsically disordered proteins.

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Eric T C Wong

Full Text Available There is a growing recognition for the importance of proteins with large intrinsically disordered (ID segments in cell signaling and regulation. ID segments in these proteins often harbor regions that mediate molecular recognition. Coupled folding and binding of the recognition regions has been proposed to confer high specificity to interactions involving ID segments. However, researchers recently questioned the origin of the interaction specificity of ID proteins because of the overrepresentation of hydrophobic residues in their interaction interfaces. Here, we focused on the role of polar and charged residues in interactions mediated by ID segments. Making use of the extended nature of most ID segments when in complex with globular proteins, we first identified large numbers of complexes between globular proteins and ID segments by using radius-of-gyration-based selection criteria. Consistent with previous studies, we found the interfaces of these complexes to be enriched in hydrophobic residues, and that these residues contribute significantly to the stability of the interaction interface. However, our analyses also show that polar interactions play a larger role in these complexes than in structured protein complexes. Computational alanine scanning and salt-bridge analysis indicate that interfaces in ID complexes are highly complementary with respect to electrostatics, more so than interfaces of globular proteins. Follow-up calculations of the electrostatic contributions to the free energy of binding uncovered significantly stronger Coulombic interactions in complexes harbouring ID segments than in structured protein complexes. However, they are counter-balanced by even higher polar-desolvation penalties. We propose that polar interactions are a key contributing factor to the observed high specificity of ID segment-mediated interactions.

A Chaotic Oscillator Based on HP Memristor Model

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Guangyi Wang

2015-01-01

Full Text Available This paper proposes a simple autonomous memristor-based oscillator for generating periodic signals. Applying an external sinusoidal excitation to the autonomous system, a nonautonomous oscillator is obtained, which contains HP memristor model and four linear circuit elements. This memristor-based oscillator can generate periodic, chaotic, and hyperchaotic signals under the periodic excitation and an appropriate set of circuit parameters. It also shows that the system exhibits alternately a hidden attractor with no equilibrium and a self-excited attractor with a line equilibrium as time goes on. Furthermore, some specialties including burst chaos, irregular periodic bifurcations, and nonintermittence chaos of the circuit are found by theoretical analysis and numerical simulations. Finally, a discrete model for the HP memristor is given and the main statistical properties of this memristor-based oscillator are verified via DSP chip experiments and NIST (National Institute of Standards and Technology tests.

A sensitization effect of hematoporphyrin oligomer (HpO) and caffeine for X-ray radiation of skin cancer

International Nuclear Information System (INIS)

Ishiguro, Kazumori; Ueda, Keiichi; Miyoshi, Norio; Nakanishi, Kazuo; Fukuda, Masaru

1990-01-01

Human malignant melanoma cells (G-361) were irradiated with X-ray for different irradiation times. The amount of DNA damage was much increased by the treatment of the cells with hematoporphyrin oligomer (HpO) before X-ray irradiation. Furthermore, it was found that the caffeine inhibited effectively the repair of the damaged DNA. Furthermore, HpO was administered before X-ray irradiation of transplantable skin tumor in C3H mice and/or caffeine was to be given the mouse after X-ray irradiation. The growth of the irradiated tumor combined with HpO and/or caffeine was more inhibited, and the necrotic area was more expanded than that of the tumor irradiated with X-ray only. Labeling Index utilizing bromodeoxyuridine (BrdU) in the viable area of the treated tumor decreased when HpO and/or caffeine were administered. The amount of DNA damage more increased in the irradiated tumor cells given HpO than the only irradiated cells. And, the repair of the damaged DNA was more delayed in the irradiated tumor cells combined with HpO and caffeine than those with other treatments. In conclusion, it was considered that HpO might be a radioactive sensitizer and caffeine enhanced the inhibition of the repair of DNA damaged. We hope that the treatment of X-ray radiation combined with HpO and caffeine is useful for clinical treatment of human malignant tumor. (author) 54 refs

A sensitization effect of hematoporphyrin oligomer (HpO) and caffeine for X-ray radiation of skin cancer

Energy Technology Data Exchange (ETDEWEB)

Ishiguro, Kazumori; Ueda, Keiichi; Miyoshi, Norio; Nakanishi, Kazuo; Fukuda, Masaru (Fukui Medical School, Matsuoka (Japan))

1990-05-01

Human malignant melanoma cells (G-361) were irradiated with X-ray for different irradiation times. The amount of DNA damage was much increased by the treatment of the cells with hematoporphyrin oligomer (HpO) before X-ray irradiation. Furthermore, it was found that the caffeine inhibited effectively the repair of the damaged DNA. Furthermore, HpO was administered before X-ray irradiation of transplantable skin tumor in C3H mice and/or caffeine was to be given the mouse after X-ray irradiation. The growth of the irradiated tumor combined with HpO and/or caffeine was more inhibited, and the necrotic area was more expanded than that of the tumor irradiated with X-ray only. Labeling Index utilizing bromodeoxyuridine (BrdU) in the viable area of the treated tumor decreased when HpO and/or caffeine were administered. The amount of DNA damage more increased in the irradiated tumor cells given HpO than the only irradiated cells. And, the repair of the damaged DNA was more delayed in the irradiated tumor cells combined with HpO and caffeine than those with other treatments. In conclusion, it was considered that HpO might be a radioactive sensitizer and caffeine enhanced the inhibition of the repair of DNA damaged. We hope that the treatment of X-ray radiation combined with HpO and caffeine is useful for clinical treatment of human malignant tumor. (author) 54 refs.

The Drosophila melanogaster CHD1 chromatin remodeling factor modulates global chromosome structure and counteracts HP1a and H3K9me2.

Science.gov (United States)

Bugga, Lakshmi; McDaniel, Ivy E; Engie, Liana; Armstrong, Jennifer A

2013-01-01

CHD1 is a conserved chromatin remodeling factor that localizes to active genes and functions in nucleosome assembly and positioning as well as histone turnover. Mouse CHD1 is required for the maintenance of stem cell pluripotency while human CHD1 may function as a tumor suppressor. To investigate the action of CHD1 on higher order chromatin structure in differentiated cells, we examined the consequences of loss of CHD1 and over-expression of CHD1 on polytene chromosomes from salivary glands of third instar Drosophila melanogaster larvae. We observed that chromosome structure is sensitive to the amount of this remodeler. Loss of CHD1 resulted in alterations of chromosome structure and an increase in the heterochromatin protein HP1a, while over-expression of CHD1 disrupted higher order chromatin structure and caused a decrease in levels of HP1a. Over-expression of an ATPase inactive form of CHD1 did not result in severe chromosomal defects, suggesting that the ATPase activity is required for this in vivo phenotype. Interestingly, changes in CHD1 protein levels did not correlate with changes in the levels of the euchromatin mark H3K4me3 or elongating RNA Polymerase II. Thus, while CHD1 is localized to transcriptionally active regions of the genome, it can function to alter the levels of HP1a, perhaps through changes in methylation of H3K9.

The Drosophila melanogaster CHD1 chromatin remodeling factor modulates global chromosome structure and counteracts HP1a and H3K9me2.

Directory of Open Access Journals (Sweden)

Lakshmi Bugga

Full Text Available CHD1 is a conserved chromatin remodeling factor that localizes to active genes and functions in nucleosome assembly and positioning as well as histone turnover. Mouse CHD1 is required for the maintenance of stem cell pluripotency while human CHD1 may function as a tumor suppressor. To investigate the action of CHD1 on higher order chromatin structure in differentiated cells, we examined the consequences of loss of CHD1 and over-expression of CHD1 on polytene chromosomes from salivary glands of third instar Drosophila melanogaster larvae. We observed that chromosome structure is sensitive to the amount of this remodeler. Loss of CHD1 resulted in alterations of chromosome structure and an increase in the heterochromatin protein HP1a, while over-expression of CHD1 disrupted higher order chromatin structure and caused a decrease in levels of HP1a. Over-expression of an ATPase inactive form of CHD1 did not result in severe chromosomal defects, suggesting that the ATPase activity is required for this in vivo phenotype. Interestingly, changes in CHD1 protein levels did not correlate with changes in the levels of the euchromatin mark H3K4me3 or elongating RNA Polymerase II. Thus, while CHD1 is localized to transcriptionally active regions of the genome, it can function to alter the levels of HP1a, perhaps through changes in methylation of H3K9.

Comparison of four urease-dependent tests of detecting HP infection

International Nuclear Information System (INIS)

Han Yuan; Huang Gang; Zhu Cuiying; Ling Liqun

2001-01-01

Objective: The aim of this study is to compare the four urease-dependent tests of detecting Hp infection. The authors used following method: 1) rapid urease test (RUT), 2) 14 C urea breath test ( 14 C-UBT), 3) 13 C urea breath test which is measured by with infrared spectrometry ( 13 C-UBT1), 4) 13 C urea breath test with mass spectrometry ( 13 C-UBT). Methods: 54 patients underwent RUT, 14 C-UBT, 13 C-UBT1, 13 C-UBT2 respectively. Results: Sensitivity and specificity, accurate rate, positive predictive value (PPV), negative predictive value (NPV), respectively, were as follows: RUT (82.1%, 80%, 81.5%, 91.4%, 63.2%), 14 C-UBT (97.4%, 100%, 98.1%, 100%, 93.8%), 13 C-UBT1 (100%, 93.3%, 98.1%, 97.5%, 100%), 13 C-UBT2 (100%, 86.7%, 96.3%, 95.1%, 100%), PPV of four tests are not significantly different (P>0.05). Conclusion: Four urease-dependent tests are high sensitive and accurate methods for detecting Hp infection. UBT is an ideal tool for diagnosis, screen and follow-up of Hp infection

TIME-SERIES PHOTOMETRY OF GLOBULAR CLUSTERS: M62 (NGC 6266), THE MOST RR LYRAE-RICH GLOBULAR CLUSTER IN THE GALAXY?

International Nuclear Information System (INIS)

Contreras, R.; Catelan, M.; Smith, H. A.; Kuehn, C. A.; Pritzl, B. J.; Borissova, J.

2010-01-01

We present new time-series CCD photometry, in the B and V bands, for the moderately metal-rich ([Fe/H] ≅ -1.3) Galactic globular cluster M62 (NGC 6266). The present data set is the largest obtained so far for this cluster and consists of 168 images per filter, obtained with the Warsaw 1.3 m telescope at the Las Campanas Observatory and the 1.3 m telescope of the Cerro Tololo Inter-American Observatory, in two separate runs over the time span of 3 months. The procedure adopted to detect the variable stars was the optimal image subtraction method (ISIS v2.2), as implemented by Alard. The photometry was performed using both ISIS and Stetson's DAOPHOT/ALLFRAME package. We have identified 245 variable stars in the cluster fields that have been analyzed so far, of which 179 are new discoveries. Of these variables, 133 are fundamental mode RR Lyrae stars (RRab), 76 are first overtone (RRc) pulsators, 4 are type II Cepheids, 25 are long-period variables (LPVs), 1 is an eclipsing binary, and 6 are not yet well classified. Such a large number of RR Lyrae stars places M62 among the top two most RR Lyrae-rich (in the sense of total number of RR Lyrae stars present) globular clusters known in the Galaxy, second only to M3 (NGC 5272) with a total of 230 known RR Lyrae stars. Since this study covers most but not all of the cluster area, it is not unlikely that M62 is in fact the most RR Lyrae-rich globular cluster in the Galaxy. In like vein, thanks to the time coverage of our data sets, we were also able to detect the largest sample of LPVs known so far in a Galactic globular cluster. We analyze a variety of Oosterhoff type indicators for the cluster, including mean periods, period distribution, Bailey diagrams, and Fourier decomposition parameters (as well as the physical parameters derived therefrom). All of these indicators clearly show that M62 is an Oosterhoff type I system. This is in good agreement with the moderately high metallicity of the cluster, in spite of its

The nature of the globular- to fibrous-actin transition.

Science.gov (United States)

Oda, Toshiro; Iwasa, Mitsusada; Aihara, Tomoki; Maéda, Yuichiro; Narita, Akihiro

2009-01-22

Actin plays crucial parts in cell motility through a dynamic process driven by polymerization and depolymerization, that is, the globular (G) to fibrous (F) actin transition. Although our knowledge about the actin-based cellular functions and the molecules that regulate the G- to F-actin transition is growing, the structural aspects of the transition remain enigmatic. We created a model of F-actin using X-ray fibre diffraction intensities obtained from well oriented sols of rabbit skeletal muscle F-actin to 3.3 A in the radial direction and 5.6 A along the equator. Here we show that the G- to F-actin conformational transition is a simple relative rotation of the two major domains by about 20 degrees. As a result of the domain rotation, the actin molecule in the filament is flat. The flat form is essential for the formation of stable, helical F-actin. Our F-actin structure model provides the basis for understanding actin polymerization as well as its molecular interactions with actin-binding proteins.

Close stellar encounters in globular clusters

International Nuclear Information System (INIS)

Bailyn, C.D.

1989-01-01

Stellar encounters are expected to produce a variety of interesting objects in the cores of globular clusters, either through the formation of binaries by tidal capture, or direct collisions. Here, I describe several attempts to observe the products of stellar encounters. In particular, the use of color maps has demonstrated the existence of a color gradient in the core of M15, which seems to be caused by a population of faint blue objects concentrated towards the cluster center. (author)

Color Gradients Within Globular Clusters: Restricted Numerical Simulation

Directory of Open Access Journals (Sweden)

Young-Jong Sohn

1997-06-01

Full Text Available The results of a restricted numerical simulation for the color gradients within globular clusters have been presented. The standard luminosity function of M3 and Salpeter's initial mass functions were used to generate model clusters as a fundamental population. Color gradients with the sample clusters for both King and power law cusp models of surface brightness distributions are discussed in the case of using the standard luminosity function. The dependence of color gradients on several parameters for the simulations with Salpeter's initial mass functions, such as slope of initial mass functions, cluster ages, metallicities, concentration parameters of King model, and slopes of power law, are also discussed. No significant radial color gradients are shown to the sample clusters which are regenerated by a random number generation technique with various parameters in both of King and power law cusp models of surface brightness distributions. Dynamical mass segregation and stellar evolution of horizontal branch stars and blue stragglers should be included for the general case of model simulations to show the observed radial color gradients within globular clusters.

The structure of the Myo4p globular tail and its function in ASH1 mRNA localization.

Science.gov (United States)

Heuck, Alexander; Fetka, Ingrid; Brewer, Daniel N; Hüls, Daniela; Munson, Mary; Jansen, Ralf-Peter; Niessing, Dierk

2010-05-03

Type V myosin (MyoV)-dependent transport of cargo is an essential process in eukaryotes. Studies on yeast and vertebrate MyoV showed that their globular tails mediate binding to the cargo complexes. In Saccharomyces cerevisiae, the MyoV motor Myo4p interacts with She3p to localize asymmetric synthesis of HO 1 (ASH1) mRNA into the bud of dividing cells. A recent study showed that localization of GFP-MS2-tethered ASH1 particles does not require the Myo4p globular tail, challenging the supposed role of this domain. We assessed ASH1 mRNA and Myo4p distribution more directly and found that their localization is impaired in cells expressing globular tail-lacking Myo4p. In vitro studies further show that the globular tail together with a more N-terminal linker region is required for efficient She3p binding. We also determined the x-ray structure of the Myo4p globular tail and identify a conserved surface patch important for She3p binding. The structure shows pronounced similarities to membrane-tethering complexes and indicates that Myo4p may not undergo auto-inhibition of its motor domain.

High-protein diet differently modifies intestinal goblet cell characteristics and mucosal cytokine expression in ileum and colon.

Science.gov (United States)

Lan, Annaïg; Andriamihaja, Mireille; Blouin, Jean-Marc; Liu, Xinxin; Descatoire, Véronique; Desclée de Maredsous, Caroline; Davila, Anne-Marie; Walker, Francine; Tomé, Daniel; Blachier, François

2015-01-01

We have previously shown that high-protein (HP) diet ingestion causes marked changes in the luminal environment of the colonic epithelium. This study aimed to evaluate the impact of such modifications on small intestinal and colonic mucosa, two segments with different transit time and physiological functions. Rats were fed with either normal protein (NP; 14% protein) or HP (53% protein) isocaloric diet for 2 weeks, and parameters related to intestinal mucous-secreting cells and to several innate/adaptive immune characteristics (myeloperoxidase activity, cytokine and epithelial TLR expression, proportion of immune cells in gut-associated lymphoid tissues) were measured in the ileum and colon. In ileum from HP animals, we observed hyperplasia of mucus-producing cells concomitant with an increased expression of Muc2 at both gene and protein levels, reduction of mucosal myeloperoxidase activity, down-regulation of Tlr4 gene expression in enterocytes and down-regulation of mucosal Th cytokines associated with CD4+ lymphocyte reduction in mesenteric lymph nodes. These changes coincided with an increased amount of acetate in the ileal luminal content. In colon, HP diet ingestion resulted in a lower number of goblet cells at the epithelial surface but increased goblet cell number in colonic crypts together with an increased Muc3 and a slight reduction of Il-6 gene expression. Our data suggest that HP diet modifies the goblet cell distribution in colon and, in ileum, increases goblet cell activity and decreases parameters related to basal gut inflammatory status. The impact of HP diet on intestinal mucosa in terms of beneficial or deleterious effects is discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

The fragmentation of proto-globular clusters. I. Thermal instabilities

International Nuclear Information System (INIS)

Murray, S.D.; Lin, D.N.C.

1989-01-01

The metal abundances among the stars within a typical globular cluster are remarkably homogeneous. This indicates that star formation in these systems was a globally coordinated event which occurred over a time span less than or comparable to the collapse time scale of the cluster. This issue is addressed by assuming that the fragmentation of a proto-globular cluster cloud proceeded in two steps. In the first step, thermal instability led to the rapid growth of initial fluctuations. This led to a large contrast in the dynamical time scales between the perturbations and the parent cloud, and the perturbations then underwent gravitational instabilities on short time scales. This process is modeled using one-dimensional hydrodynamic simulations of clouds both with and without external heat sources and self-gravity. The models include the effects of a non-equilibrium H2 abundance. The results indicate that fragmentation can occur on time scales significantly less than the dynamical time scale of the parent cloud. 21 refs

Globular hepatic amyloid is highly sensitive and specific for LECT2 amyloidosis.

Science.gov (United States)

Chandan, Vishal S; Shah, Sejal S; Lam-Himlin, Dora M; Petris, Giovanni De; Mereuta, Oana M; Dogan, Ahmet; Torbenson, Michael S; Wu, Tsung-Teh

2015-04-01

Globular hepatic amyloid (GHA) is rare, and its clinical significance remains unclear. Recently, leukocyte chemotactic factor-associated amyloidosis (ALECT2) has been reported to involve the liver, showing a globular pattern. We reviewed 70 consecutive cases of hepatic amyloidosis to determine the prevalence and morphology of hepatic amyloid subtypes, especially ALECT2 and its association with GHA. Each case was reviewed for amyloid subtype (immunohistochemistry and/or mass spectrometry), its pattern (linear or globular), and distribution (vascular, perisinusoidal, or stromal). In addition, 24 cases of confirmed hepatic ALECT2 on mass spectrometry from our consultation files were also reviewed. LECT2 immunostaining was performed in 49 cases. Of the 70 cases, immunoglobulin light chain (AL) type was most common with 41 cases (59%), followed by transthyretin (ATTR) 15 cases (22%), 3 cases each of fibrinogen A (AFib) (4%), serum amyloid A (AA) (4%), and ALECT2 (4%), 2 cases of apolipoproteins (AApoA1) (3%), and 3 cases (4%) were unclassified. Three of our 70 cases (4%), with ALECT2, and all 24 cases (100%) of mass spectrometry-confirmed hepatic ALECT2 showed only GHA deposits in the hepatic sinusoids and portal tracts. Three (4%) other cases of AL type showed a focal globular pattern admixed with prominent linear amyloid. None of the other amyloid subtypes showed GHA. LECT2 immunostain was positive in all 27 cases (100%) of ALECT2 and negative in the other 22 non-ALECT2 cases (100%) (14 AL, 5 ATTR, 1 AA, 1 AFib, 1 AApoA1). Pure GHA is uncommon (4%) but is highly specific for ALECT2, and LECT2 immunostain is helpful in confirming this amyloid type.

A parallel direct solver for the self-adaptive hp Finite Element Method

KAUST Repository

Paszyński, Maciej R.

2010-03-01

In this paper we present a new parallel multi-frontal direct solver, dedicated for the hp Finite Element Method (hp-FEM). The self-adaptive hp-FEM generates in a fully automatic mode, a sequence of hp-meshes delivering exponential convergence of the error with respect to the number of degrees of freedom (d.o.f.) as well as the CPU time, by performing a sequence of hp refinements starting from an arbitrary initial mesh. The solver constructs an initial elimination tree for an arbitrary initial mesh, and expands the elimination tree each time the mesh is refined. This allows us to keep track of the order of elimination for the solver. The solver also minimizes the memory usage, by de-allocating partial LU factorizations computed during the elimination stage of the solver, and recomputes them for the backward substitution stage, by utilizing only about 10% of the computational time necessary for the original computations. The solver has been tested on 3D Direct Current (DC) borehole resistivity measurement simulations problems. We measure the execution time and memory usage of the solver over a large regular mesh with 1.5 million degrees of freedom as well as on the highly non-regular mesh, generated by the self-adaptive h p-FEM, with finite elements of various sizes and polynomial orders of approximation varying from p = 1 to p = 9. From the presented experiments it follows that the parallel solver scales well up to the maximum number of utilized processors. The limit for the solver scalability is the maximum sequential part of the algorithm: the computations of the partial LU factorizations over the longest path, coming from the root of the elimination tree down to the deepest leaf. © 2009 Elsevier Inc. All rights reserved.

78 FR 48468 - Hewlett Packard Company, Hewlett Packard Enterprise Business Unit, EG HP Storage, Enterprise...

Science.gov (United States)

2013-08-08

..., Hewlett Packard Enterprise Business Unit, EG HP Storage, Enterprise Storage, Servers and Networking Storage, APP Management, Research and Development Group, Andover, Massachusetts; Notice of Investigation... Enterprise Business Unit, EG HP Storage, Enterprise Storage, Servers and Networking Storage Division, APP...

Globular Cluster Variable Stars—Atlas and Coordinate Improvement using AAVSOnet Telescopes (Abstract)

Science.gov (United States)

Welch, D.; Henden, A.; Bell, T.; Suen, C.; Fare, I.; Sills, A.

2015-12-01

(Abstract only) The variable stars of globular clusters have played and continue to play a significant role in our understanding of certain classes of variable stars. Since all stars associated with a cluster have the same age, metallicity, distance and usually very similar (if not identical reddenings), such variables can produce uniquely powerful constraints on where certain types of pulsation behaviors are excited. Advanced amateur astronomers are increasingly well-positioned to provide long-term CCD monitoring of globular cluster variable star but are hampered by a long history of poor or inaccessible finder charts and coordinates. Many of variable-rich clusters have published photographic finder charts taken in relatively poor seeing with blue-sensitive photographic plates. While useful signal-to-noise ratios are relatively straightforward to achieve for RR Lyrae, Type 2 Cepheids, and red giant variables, correct identification remains a difficult issue—particularly when images are taken at V or longer wavelengths. We describe the project and report its progress using the OC61, TMO61, and SRO telescopes of AAVSOnet after the first year of image acquisition and demonstrate several of the data products being developed for globular cluster variables.

Parâmetros astrofísicos de estrelas gigantes do aglomerado globular 47 Tucanae

Science.gov (United States)

Alves-Brito, A.; Barbuy, B.

2003-08-01

Os aglomerados globulares são considerados laboratórios astrofísicos para a verificação da teoria de evolução estelar, bem como a trajetória químio-dinâmica das galáxias hospedeiras. Em particular, 47 Tucanae (NGC 104) configura-se como um dos mais extensivamente estudados aglomerados globulares da Galáxia devido a relativa proximidade ao Sol (R¤ = 4.5 kpc) e alta latitute galáctica (b = -44°,89). Neste trabalho, apresentamos a velocidade radial heliocêntrica e os parâmetros atmosféricos (Teff, logg, [Fe/H]) de 5 estrelas gigantes do aglomerado globular 47 Tucanae. Os espectros foram obtidos pelo espectrógrafo UVES (Ultaviolet Visual Echelle Spectrograph) de alta resolução (R = 60000) e alta razão sinal-ruído (S/N > 200), acoplado ao telescópio de 8,2m Kueyen do VLT (Very Large Telescope). Nós encontramos = -22,43 +/- 3,97 km/s, [Fe/H] ~ -0.7, 1,2 estrelas cobrem um intervalo de magnitude 12,2 < V < 14,2. Os parâmetros atmosféricos são fundamentais para a construção de espectros sintéticos de outros aglomerados globulares ricos em metais. Trabalho financiado pela FAPESP e pelo CNPq.

Intestinal epithelial cell surface glycosylation in mice. I. Effect of high-protein diet.

Science.gov (United States)

Gupta, R; Jaswal, V M; Meenu Mahmood, A

1992-01-01

The effects of variation in dietary protein content have been investigated on brush border glycosylation and enzyme activities in mice small intestine. The comparison of different parameters was made between the mice fed 30% (high protein, HP) and 18% protein (pair-fed, PF, and ad libitum-fed) for 21 days. The activities of brush border sucrase, lactase, p-nitrophenyl (PNP)-beta-D-glucosidase and PNP-beta-D-galactosidase were reduced in the HP diet-fed mice compared to PF and ad libitum-fed controls. Alkaline phosphatase and leucine amino-peptidase activities were significantly enhanced while gamma-glutamyl transpeptidase activity was unaltered under these conditions. Total hexoses and sialic acid content in the brush borders were reduced significantly in the test group compared to the controls while hexosamine and fucose contents remained essentially similar in different groups. The results on the binding of wheat germ agglutinin and Ulex europaeus agglutininI to microvillus membranes corroborated the chemical analysis data on sialic acid and fucose contents of the membranes. Peanut agglutinin binding was enhanced in mice from the HP group. Incorporation of (14C)-mannose into membranes was significantly less in HP diet-fed mice. These results indicate that the feeding of HP diet to mice brings about marked alterations in small intestinal epithelial cell surface glycosylation and enzyme functions.

Spatially adaptive hp refinement approach for PN neutron transport equation using spectral element method

International Nuclear Information System (INIS)

Nahavandi, N.; Minuchehr, A.; Zolfaghari, A.; Abbasi, M.

2015-01-01

Highlights: • Powerful hp-SEM refinement approach for P N neutron transport equation has been presented. • The method provides great geometrical flexibility and lower computational cost. • There is a capability of using arbitrary high order and non uniform meshes. • Both posteriori and priori local error estimation approaches have been employed. • High accurate results are compared against other common adaptive and uniform grids. - Abstract: In this work we presented the adaptive hp-SEM approach which is obtained from the incorporation of Spectral Element Method (SEM) and adaptive hp refinement. The SEM nodal discretization and hp adaptive grid-refinement for even-parity Boltzmann neutron transport equation creates powerful grid refinement approach with high accuracy solutions. In this regard a computer code has been developed to solve multi-group neutron transport equation in one-dimensional geometry using even-parity transport theory. The spatial dependence of flux has been developed via SEM method with Lobatto orthogonal polynomial. Two commonly error estimation approaches, the posteriori and the priori has been implemented. The incorporation of SEM nodal discretization method and adaptive hp grid refinement leads to high accurate solutions. Coarser meshes efficiency and significant reduction of computer program runtime in comparison with other common refining methods and uniform meshing approaches is tested along several well-known transport benchmarks

Maintenance of the marginal-zone B cell compartment specifically requires the RNA-binding protein ZFP36L1.

Science.gov (United States)

Newman, Rebecca; Ahlfors, Helena; Saveliev, Alexander; Galloway, Alison; Hodson, Daniel J; Williams, Robert; Besra, Gurdyal S; Cook, Charlotte N; Cunningham, Adam F; Bell, Sarah E; Turner, Martin

2017-06-01

RNA-binding proteins of the ZFP36 family are best known for inhibiting the expression of cytokines through binding to AU-rich elements in the 3' untranslated region and promoting mRNA decay. Here we identified an indispensable role for ZFP36L1 as the regulator of a post-transcriptional hub that determined the identity of marginal-zone B cells by promoting their proper localization and survival. ZFP36L1 controlled a gene-expression program related to signaling, cell adhesion and locomotion; it achieved this in part by limiting expression of the transcription factors KLF2 and IRF8, which are known to enforce the follicular B cell phenotype. These mechanisms emphasize the importance of integrating transcriptional and post-transcriptional processes by RNA-binding proteins for maintaining cellular identity among closely related cell types.

High-Protein Intake during Weight Loss Therapy Eliminates the Weight-Loss-Induced Improvement in Insulin Action in Obese Postmenopausal Women

Directory of Open Access Journals (Sweden)

Gordon I. Smith

2016-10-01

Full Text Available High-protein (HP intake during weight loss (WL therapy is often recommended because it reduces the loss of lean tissue mass. However, HP intake could have adverse effects on metabolic function, because protein ingestion reduces postprandial insulin sensitivity. In this study, we compared the effects of ∼10% WL with a hypocaloric diet containing 0.8 g protein/kg/day and a hypocaloric diet containing 1.2 g protein/kg/day on muscle insulin action in postmenopausal women with obesity. We found that HP intake reduced the WL-induced decline in lean tissue mass by ∼45%. However, HP intake also prevented the WL-induced improvements in muscle insulin signaling and insulin-stimulated glucose uptake, as well as the WL-induced adaptations in oxidative stress and cell structural biology pathways. Our data demonstrate that the protein content of a WL diet can have profound effects on metabolic function and underscore the importance of considering dietary macronutrient composition during WL therapy for people with obesity.

Contribution of High-Pressure-Induced Protein Modifications to the Microenvironment and Functional Properties of Rabbit Meat Sausages.

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Xue, Siwen; Yu, Xiaobo; Yang, Huijuan; Xu, Xinglian; Ma, Hanjun; Zhou, Guanghong

2017-06-01

Rabbit meat batters were subjected to high pressure (HP, 100 to 300 MPa for 3, 9, or 15 min) to elucidate their effects on proteins structures, the microenvironment, and the resulting functionalities of the subsequently heated products. To determine these effects, we investigated structural and microenvironmental changes using Raman spectroscopy and also expressible moisture content, textural characteristics, and dynamic rheological properties of batters during heating (20 to 80 °C). Untreated samples served as controls. Analysis of specific Raman spectral regions demonstrated that applications of HP to rabbit meat batters tended to induce the transformation of the all-gauche S-S conformation to gauche-gauche-trans in the batter system. HP treatment higher than 100 MPa for 9 min promoted secondary structural rearrangements, and molecular polarity enhancement in the proteins prior to cooking. Also, increases of O-H stretching intensities of rabbit meat sausages were obtained by HP treatment, denoting the strengthening of water-holding capacity. These HP-induced alterations resulted in improved texture and, perhaps, improved juiciness of rabbit meat sausages (P functionalities of gel-type products through modification of meat proteins. © 2017 Institute of Food Technologists®.

Conformational energy calculations on polypeptides and proteins: use of a statistical mechanical procedure for evaluating structure and properties.

Science.gov (United States)

Scheraga, H A; Paine, G H

1986-01-01

We are using a variety of theoretical and computational techniques to study protein structure, protein folding, and higher-order structures. Our earlier work involved treatments of liquid water and aqueous solutions of nonpolar and polar solutes, computations of the stabilities of the fundamental structures of proteins and their packing arrangements, conformations of small cyclic and open-chain peptides, structures of fibrous proteins (collagen), structures of homologous globular proteins, introduction of special procedures as constraints during energy minimization of globular proteins, and structures of enzyme-substrate complexes. Recently, we presented a new methodology for predicting polypeptide structure (described here); the method is based on the calculation of the probable and average conformation of a polypeptide chain by the application of equilibrium statistical mechanics in conjunction with an adaptive, importance sampling Monte Carlo algorithm. As a test, it was applied to Met-enkephalin.

My 65 years in protein chemistry.

Science.gov (United States)

Scheraga, Harold A

2015-05-01

This is a tour of a physical chemist through 65 years of protein chemistry from the time when emphasis was placed on the determination of the size and shape of the protein molecule as a colloidal particle, with an early breakthrough by James Sumner, followed by Linus Pauling and Fred Sanger, that a protein was a real molecule, albeit a macromolecule. It deals with the recognition of the nature and importance of hydrogen bonds and hydrophobic interactions in determining the structure, properties, and biological function of proteins until the present acquisition of an understanding of the structure, thermodynamics, and folding pathways from a linear array of amino acids to a biological entity. Along the way, with a combination of experiment and theoretical interpretation, a mechanism was elucidated for the thrombin-induced conversion of fibrinogen to a fibrin blood clot and for the oxidative-folding pathways of ribonuclease A. Before the atomic structure of a protein molecule was determined by x-ray diffraction or nuclear magnetic resonance spectroscopy, experimental studies of the fundamental interactions underlying protein structure led to several distance constraints which motivated the theoretical approach to determine protein structure, and culminated in the Empirical Conformational Energy Program for Peptides (ECEPP), an all-atom force field, with which the structures of fibrous collagen-like proteins and the 46-residue globular staphylococcal protein A were determined. To undertake the study of larger globular proteins, a physics-based coarse-grained UNited-RESidue (UNRES) force field was developed, and applied to the protein-folding problem in terms of structure, thermodynamics, dynamics, and folding pathways. Initially, single-chain and, ultimately, multiple-chain proteins were examined, and the methodology was extended to protein-protein interactions and to nucleic acids and to protein-nucleic acid interactions. The ultimate results led to an understanding

Evidence from stellar abundances for a large age difference between two globular clusters

International Nuclear Information System (INIS)

Dickens, R.J.; Croke, B.F.W.; Cannon, R.D.; Bell, R.A.

1991-01-01

The globular clusters NGC288 and NGC362 are central to recent claims of large age differences (∼3 Gyr) between globular clusters associated with our Galaxy. According to standard models for the formation of the Galaxy, the system of globular clusters formed during the dynamical collapse of the protogalactic cloud, a process which should have lasted no more than 1 Gyr. But the claimed age differences are derived from stellar evolution models using assumed CNO abundances, and uncertainty in the actual CNO abundances of about a factor of three could account for an apparent 2-Gyr age difference. We have accurately measured abundances in red giants in NGC288 and NGC362, and find that the Fe abundance and the sum of the C, N and O abundances are essentially the same in every star studied. By eliminating compositional differences and thus confirming the reality of the age difference, these results imply a cluster formation period that is hard to reconcile with the standard collapse model. (author)

The SLUGGS survey: globular cluster stellar population trends from weak absorption lines in stacked spectra

Science.gov (United States)

Usher, Christopher; Forbes, Duncan A.; Brodie, Jean P.; Romanowsky, Aaron J.; Strader, Jay; Conroy, Charlie; Foster, Caroline; Pastorello, Nicola; Pota, Vincenzo; Arnold, Jacob A.

2015-01-01

As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ˜90 Å-1. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the Hα and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet-colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour-metallicity relation between galaxies. Two possible explanations for the colour-metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stacking spectra by magnitude, we see that the colours become redder and metal line indices stronger with brighter magnitudes. These trends are consistent with the previously reported `blue tilts' being mass-metallicity relations.

Contribution to the study of proteins and peptides structure by hydrogen isotopic exchange

International Nuclear Information System (INIS)

Nabedryk-Viala, Eliane.

1978-01-01

Development of hydrogen exchange measurement methods to study the structure and the molecular interaction of globular protein molecules in aqueous solution (ribonuclease A, cytochrome c, coupling factors of chloroplasts), in peptide hormones in trifluoroethanol solution (angiotensin II, corticotropin) and in proteins of membranes (rhodopsin) [fr

Structure and Dynamics of the Globular Cluster Palomar 13

Science.gov (United States)

Bradford, J. D.; Geha, M.; Muñoz, R. R.; Santana, F. A.; Simon, J. D.; Côté, P.; Stetson, P. B.; Kirby, E.; Djorgovski, S. G.

2011-12-01

We present Keck/DEIMOS spectroscopy and Canada-France-Hawaii Telescope/MegaCam photometry for the Milky Way globular cluster Palomar 13. We triple the number of spectroscopically confirmed members, including many repeat velocity measurements. Palomar 13 is the only known globular cluster with possible evidence for dark matter, based on a Keck/High Resolution Echelle Spectrometer 21 star velocity dispersion of σ = 2.2 ± 0.4 km s-1. We reproduce this measurement, but demonstrate that it is inflated by unresolved binary stars. For our sample of 61 stars, the velocity dispersion is σ = 0.7+0.6 -0.5 km s-1. Combining our DEIMOS data with literature values, our final velocity dispersion is σ = 0.4+0.4 -0.3 km s-1. We determine a spectroscopic metallicity of [Fe/H] = -1.6 ± 0.1 dex, placing a 1σ upper limit of σ[Fe/H] ~ 0.2 dex on any internal metallicity spread. We determine Palomar 13's total luminosity to be MV = -2.8 ± 0.4, making it among the least luminous known globular clusters. The photometric isophotes are regular out to the half-light radius and mildly irregular outside this radius. The outer surface brightness profile slope is shallower than typical globular clusters (Σvpropr η, η = -2.8 ± 0.3). Thus at large radius, tidal debris is likely affecting the appearance of Palomar 13. Combining our luminosity with the intrinsic velocity dispersion, we find a dynamical mass of M 1/2 = 1.3+2: 7 -1.3 × 103 M ⊙ and a mass-to-light ratio of M/LV = 2.4+5.0 -2.4 M ⊙/L ⊙. Within our measurement errors, the mass-to-light ratio agrees with the theoretical predictions for a single stellar population. We conclude that, while there is some evidence for tidal stripping at large radius, the dynamical mass of Palomar 13 is consistent with its stellar mass and neither significant dark matter, nor extreme tidal heating, is required to explain the cluster dynamics. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a

Milk protein intake, the metabolic-endocrine response, and growth in infancy: data from a randomized clinical trial.

Science.gov (United States)

Socha, Piotr; Grote, Veit; Gruszfeld, Dariusz; Janas, Roman; Demmelmair, Hans; Closa-Monasterolo, Ricardo; Subías, Joaquín Escribano; Scaglioni, Silvia; Verduci, Elvira; Dain, Elena; Langhendries, Jean-Paul; Perrin, Emmanuel; Koletzko, Berthold

2011-12-01

Protein intake in early infancy has been suggested to be an important risk factor for later obesity, but information on potential mechanisms is very limited. This study examined the influence of protein intake in infancy on serum amino acids, insulin, and the insulin-like growth factor I (IGF-I) axis and its possible relation to growth in the first 2 y of life. In a multicenter European study, 1138 healthy, formula-fed infants were randomly assigned to receive cow-milk-based infant and follow-on formulas with lower protein (LP; 1.77 and 2.2 g protein/100 kcal) or higher protein (HP; 2.9 and 4.4 g protein/100 kcal) contents for the first year. Biochemical variables were measured at age 6 mo in 339 infants receiving LP formula and 333 infants receiving HP formula and in 237 breastfed infants. Essential amino acids, especially branched-chain amino acids, IGF-I, and urinary C-peptide:creatinine ratio, were significantly (P < 0.001) higher in the HP group than in the LP group, whereas IGF-binding protein (IGF-BP) 2 was lower and IGF-BP3 did not differ significantly. The median IGF-I total serum concentration was 48.4 ng/mL (25th, 75th percentile: 27.2, 81.8 ng/mL) in the HP group and 34.7 ng/mL (17.7, 57.5 ng/mL) in the LP group; the urine C-peptide:creatinine ratios were 140.6 ng/mg (80.0, 203.8 ng/mg) and 107.3 ng/mg (65.2, 194.7 ng/mg), respectively. Most essential amino acids, IGF-I, C-peptide, and urea increased significantly in both the LP and HP groups compared with the breastfed group. Total IGF-I was significantly associated with growth until 6 mo but not thereafter. HP intake stimulates the IGF-I axis and insulin release in infancy. IGF-I enhances growth during the first 6 mo of life. This trial was registered at clinicaltrials.gov as NCT00338689.

Increased protein intake reduces lean body mass loss during weight loss in athletes.

Science.gov (United States)

Mettler, Samuel; Mitchell, Nigel; Tipton, Kevin D

2010-02-01

To examine the influence of dietary protein on lean body mass loss and performance during short-term hypoenergetic weight loss in athletes. In a parallel design, 20 young healthy resistance-trained athletes were examined for energy expenditure for 1 wk and fed a mixed diet (15% protein, 100% energy) in the second week followed by a hypoenergetic diet (60% of the habitual energy intake), containing either 15% (approximately 1.0 g x kg(-1)) protein (control group, n = 10; CP) or 35% (approximately 2.3 g x kg(-1)) protein (high-protein group, n = 10; HP) for 2 wk. Subjects continued their habitual training throughout the study. Total, lean body, and fat mass, performance (squat jump, maximal isometric leg extension, one-repetition maximum (1RM) bench press, muscle endurance bench press, and 30-s Wingate test) and fasting blood samples (glucose, nonesterified fatty acids (NEFA), glycerol, urea, cortisol, free testosterone, free Insulin-like growth factor-1 (IGF-1), and growth hormone), and psychologic measures were examined at the end of each of the 4 wk. Total (-3.0 +/- 0.4 and -1.5 +/- 0.3 kg for the CP and HP, respectively, P = 0.036) and lean body mass loss (-1.6 +/- 0.3 and -0.3 +/- 0.3 kg, P = 0.006) were significantly larger in the CP compared with those in the HP. Fat loss, performance, and most blood parameters were not influenced by the diet. Urea was higher in HP, and NEFA and urea showed a group x time interaction. Fatigue ratings and "worse than normal" scores on the Daily Analysis of Life Demands for Athletes were higher in HP. These results indicate that approximately 2.3 g x kg(-1) or approximately 35% protein was significantly superior to approximately 1.0 g x kg(-1) or approximately 15% energy protein for maintenance of lean body mass in young healthy athletes during short-term hypoenergetic weight loss.

The SUMO project I. A survey of multiple populations in globular clusters

Science.gov (United States)

Monelli, M.; Milone, A. P.; Stetson, P. B.; Marino, A. F.; Cassisi, S.; del Pino Molina, A.; Salaris, M.; Aparicio, A.; Asplund, M.; Grundahl, F.; Piotto, G.; Weiss, A.; Carrera, R.; Cebrián, M.; Murabito, S.; Pietrinferni, A.; Sbordone, L.

2013-05-01

We present a general overview and the first results of the SUMO project (a SUrvey of Multiple pOpulations in Globular Clusters). The objective of this survey is the study of multiple stellar populations in the largest sample of globular clusters homogeneously analysed to date. To this aim we obtained high signal-to-noise (S/N > 50) photometry for main sequence stars with mass down to ˜0.5 M⊙ in a large sample of clusters using both archival and proprietary U, B, V and I data from ground-based telescopes. In this paper, we focus on the occurrence of multiple stellar populations in 23 clusters. We define a new photometric index, cU, B, I = (U - B) - (B - I), which turns out to be very effective for identifying multiple sequences along the red giant branch (RGB). We found that in the V-cU, B, I diagram all clusters presented in this paper show broadened or multimodal RGBs, with the presence of two or more components. We found a direct connection with the chemical properties of different sequences, which display different abundances of light elements (O, Na, C, N and Al). The cU, B, I index is also a powerful tool for identifying distinct sequences of stars along the horizontal branch and, for the first time in the case of NGC 104 (47 Tuc), along the asymptotic giant branch. Our results demonstrate that (i) the presence of more than two stellar populations is a common feature amongst globular clusters, as already highlighted in previous work; (ii) multiple sequences with different chemical contents can be easily identified by using standard Johnson photometry obtained with ground-based facilities; (iii) in the study of globular cluster multiple stellar populations the cU, B, I index is an alternative to spectroscopy, and has the advantage of larger statistics.

Structural features that predict real-value fluctuations of globular proteins.

Science.gov (United States)

Jamroz, Michal; Kolinski, Andrzej; Kihara, Daisuke

2012-05-01

It is crucial to consider dynamics for understanding the biological function of proteins. We used a large number of molecular dynamics (MD) trajectories of nonhomologous proteins as references and examined static structural features of proteins that are most relevant to fluctuations. We examined correlation of individual structural features with fluctuations and further investigated effective combinations of features for predicting the real value of residue fluctuations using the support vector regression (SVR). It was found that some structural features have higher correlation than crystallographic B-factors with fluctuations observed in MD trajectories. Moreover, SVR that uses combinations of static structural features showed accurate prediction of fluctuations with an average Pearson's correlation coefficient of 0.669 and a root mean square error of 1.04 Å. This correlation coefficient is higher than the one observed in predictions by the Gaussian network model (GNM). An advantage of the developed method over the GNMs is that the former predicts the real value of fluctuation. The results help improve our understanding of relationships between protein structure and fluctuation. Furthermore, the developed method provides a convienient practial way to predict fluctuations of proteins using easily computed static structural features of proteins. Copyright © 2012 Wiley Periodicals, Inc.

Genome-wide analysis reveals the extent of EAV-HP integration in domestic chicken.

Science.gov (United States)

Wragg, David; Mason, Andrew S; Yu, Le; Kuo, Richard; Lawal, Raman A; Desta, Takele Taye; Mwacharo, Joram M; Cho, Chang-Yeon; Kemp, Steve; Burt, David W; Hanotte, Olivier

2015-10-14

EAV-HP is an ancient retrovirus pre-dating Gallus speciation, which continues to circulate in modern chicken populations, and led to the emergence of avian leukosis virus subgroup J causing significant economic losses to the poultry industry. We mapped EAV-HP integration sites in Ethiopian village chickens, a Silkie, Taiwan Country chicken, red junglefowl Gallus gallus and several inbred experimental lines using whole-genome sequence data. An average of 75.22 ± 9.52 integration sites per bird were identified, which collectively group into 279 intervals of which 5 % are common to 90 % of the genomes analysed and are suggestive of pre-domestication integration events. More than a third of intervals are specific to individual genomes, supporting active circulation of EAV-HP in modern chickens. Interval density is correlated with chromosome length (P < 2.31(-6)), and 27 % of intervals are located within 5 kb of a transcript. Functional annotation clustering of genes reveals enrichment for immune-related functions (P < 0.05). Our results illustrate a non-random distribution of EAV-HP in the genome, emphasising the importance it may have played in the adaptation of the species, and provide a platform from which to extend investigations on the co-evolutionary significance of endogenous retroviral genera with their hosts.

Globular adiponectin ameliorates metabolic insulin resistance via AMPK-mediated restoration of microvascular insulin responses

Science.gov (United States)

Zhao, Lina; Fu, Zhuo; Wu, Jing; Aylor, Kevin W; Barrett, Eugene J; Cao, Wenhong; Liu, Zhenqi

2015-01-01

Abstract Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance, and microvasculature plays a critical role in the regulation of insulin action in muscle. Here we tested whether adiponectin replenishment could improve metabolic insulin sensitivity in male rats fed a high-fat diet (HFD) via the modulation of microvascular insulin responses. Male Sprague–Dawley rats were fed either a HFD or low-fat diet (LFD) for 4 weeks. Small resistance artery myograph changes in tension, muscle microvascular recruitment and metabolic response to insulin were determined. Compared with rats fed a LFD, HFD feeding abolished the vasodilatory actions of globular adiponectin (gAd) and insulin on pre-constricted distal saphenous arteries. Pretreatment with gAd improved insulin responses in arterioles isolated from HFD rats, which was blocked by AMP-activated protein kinase (AMPK) inhibition. Similarly, HFD abolished microvascular responses to either gAd or insulin and decreased insulin-stimulated glucose disposal by ∼60%. However, supplementing gAd fully rescued insulin’s microvascular action and significantly improved the metabolic responses to insulin in HFD male rats and these actions were abolished by inhibition of either AMPK or nitric oxide production. We conclude that HFD induces vascular adiponectin and insulin resistance but gAd administration can restore vascular insulin responses and improve insulin’s metabolic action via an AMPK- and nitric oxide-dependent mechanism in male rats. Key points Adiponectin is an adipokine with anti-inflammatory and anti-diabetic properties. Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance in obesity and diabetes. Insulin resistance is present in muscle microvasculature and this may contribute to decreased insulin delivery to, and action in, muscle. In this study we examined whether adiponectin ameliorates metabolic insulin resistance by affecting muscle

Positive Selection Drives the Evolution of rhino, a Member of the Heterochromatin Protein 1 Family in Drosophila.

Directory of Open Access Journals (Sweden)

2005-07-01

Full Text Available Heterochromatin comprises a significant component of many eukaryotic genomes. In comparison to euchromatin, heterochromatin is gene poor, transposon rich, and late replicating. It serves many important biological roles, from gene silencing to accurate chromosome segregation, yet little is known about the evolutionary constraints that shape heterochromatin. A complementary approach to the traditional one of directly studying heterochromatic DNA sequence is to study the evolution of proteins that bind and define heterochromatin. One of the best markers for heterochromatin is the heterochromatin protein 1 (HP1, which is an essential, nonhistone chromosomal protein. Here we investigate the molecular evolution of five HP1 paralogs present in Drosophila melanogaster. Three of these paralogs have ubiquitous expression patterns in adult Drosophila tissues, whereas HP1D/rhino and HP1E are expressed predominantly in ovaries and testes respectively. The HP1 paralogs also have distinct localization preferences in Drosophila cells. Thus, Rhino localizes to the heterochromatic compartment in Drosophila tissue culture cells, but in a pattern distinct from HP1A and lysine-9 dimethylated H3. Using molecular evolution and population genetic analyses, we find that rhino has been subject to positive selection in all three domains of the protein: the N-terminal chromo domain, the C-terminal chromo-shadow domain, and the hinge region that connects these two modules. Maximum likelihood analysis of rhino sequences from 20 species of Drosophila reveals that a small number of residues of the chromo and shadow domains have been subject to repeated positive selection. The rapid and positive selection of rhino is highly unusual for a gene encoding a chromosomal protein and suggests that rhino is involved in a genetic conflict that affects the germline, belying the notion that heterochromatin is simply a passive recipient of "junk DNA" in eukaryotic genomes.

Positive selection drives the evolution of rhino, a member of the heterochromatin protein 1 family in Drosophila.

Directory of Open Access Journals (Sweden)

Danielle Vermaak

2005-07-01

Full Text Available Heterochromatin comprises a significant component of many eukaryotic genomes. In comparison to euchromatin, heterochromatin is gene poor, transposon rich, and late replicating. It serves many important biological roles, from gene silencing to accurate chromosome segregation, yet little is known about the evolutionary constraints that shape heterochromatin. A complementary approach to the traditional one of directly studying heterochromatic DNA sequence is to study the evolution of proteins that bind and define heterochromatin. One of the best markers for heterochromatin is the heterochromatin protein 1 (HP1, which is an essential, nonhistone chromosomal protein. Here we investigate the molecular evolution of five HP1 paralogs present in Drosophila melanogaster. Three of these paralogs have ubiquitous expression patterns in adult Drosophila tissues, whereas HP1D/rhino and HP1E are expressed predominantly in ovaries and testes respectively. The HP1 paralogs also have distinct localization preferences in Drosophila cells. Thus, Rhino localizes to the heterochromatic compartment in Drosophila tissue culture cells, but in a pattern distinct from HP1A and lysine-9 dimethylated H3. Using molecular evolution and population genetic analyses, we find that rhino has been subject to positive selection in all three domains of the protein: the N-terminal chromo domain, the C-terminal chromo-shadow domain, and the hinge region that connects these two modules. Maximum likelihood analysis of rhino sequences from 20 species of Drosophila reveals that a small number of residues of the chromo and shadow domains have been subject to repeated positive selection. The rapid and positive selection of rhino is highly unusual for a gene encoding a chromosomal protein and suggests that rhino is involved in a genetic conflict that affects the germline, belying the notion that heterochromatin is simply a passive recipient of "junk DNA" in eukaryotic genomes.

Prolonged Adaptation to a Low or High Protein Diet Does Not Modulate Basal Muscle Protein Synthesis Rates - A Substudy.

Science.gov (United States)

Hursel, Rick; Martens, Eveline A P; Gonnissen, Hanne K J; Hamer, Henrike M; Senden, Joan M G; van Loon, Luc J C; Westerterp-Plantenga, Margriet S

2015-01-01

Based on controlled 36 h experiments a higher dietary protein intake causes a positive protein balance and a negative fat balance. A positive net protein balance may support fat free mass accrual. However, few data are available on the impact of more prolonged changes in habitual protein intake on whole-body protein metabolism and basal muscle protein synthesis rates. To assess changes in whole-body protein turnover and basal muscle protein synthesis rates following 12 weeks of adaptation to a low versus high dietary protein intake. A randomized parallel study was performed in 40 subjects who followed either a high protein (2.4 g protein/kg/d) or low protein (0.4 g protein/kg/d) energy-balanced diet (30/35/35% or 5/60/35% energy from protein/carbohydrate/fat) for a period of 12 weeks. A subgroup of 7 men and 8 women (body mass index: 22.8±2.3 kg/m2, age: 24.3±4.9 y) were selected to evaluate the impact of prolonged adaptation to either a high or low protein intake on whole body protein metabolism and basal muscle protein synthesis rates. After the diet, subjects received continuous infusions with L-[ring-2H5]phenylalanine and L-[ring-2H2]tyrosine in an overnight fasted state, with blood samples and muscle biopsies being collected to assess post-absorptive whole-body protein turnover and muscle protein synthesis rates in vivo in humans. After 12 weeks of intervention, whole-body protein balance in the fasted state was more negative in the high protein treatment when compared with the low protein treatment (-4.1±0.5 vs -2.7±0.6 μmol phenylalanine/kg/h;Pprotein breakdown (43.0±4.4 vs 37.8±3.8 μmol phenylalanine/kg/h;Psynthesis (38.9±4.2 vs 35.1±3.6 μmol phenylalanine/kg/h;Pprotein group. Basal muscle protein synthesis rates were maintained on a low vs high protein diet (0.042±0.01 vs 0.045±0.01%/h;P = 0.620). In the overnight fasted state, adaptation to a low-protein intake (0.4 g/kg/d) does not result in a more negative whole-body protein balance and

Weighted curve-fitting program for the HP 67/97 calculator

International Nuclear Information System (INIS)

Stockli, M.P.

1983-01-01

The HP 67/97 calculator provides in its standard equipment a curve-fit program for linear, logarithmic, exponential and power functions that is quite useful and popular. However, in more sophisticated applications, proper weights for data are often essential. For this purpose a program package was created which is very similar to the standard curve-fit program but which includes the weights of the data for proper statistical analysis. This allows accurate calculation of the uncertainties of the fitted curve parameters as well as the uncertainties of interpolations or extrapolations, or optionally the uncertainties can be normalized with chi-square. The program is very versatile and allows one to perform quite difficult data analysis in a convenient way with the pocket calculator HP 67/97

Acute phase proteins in bovine milk in an experimental model of Staphylococcus aureus subclinical mastitis

DEFF Research Database (Denmark)

Eckersall, P D; Young, F J; Nolan, A M

2006-01-01

and serum amyloid A increase in serum during mastitis. The concentrations of these proteins were determined in an experimental model using a field strain of Staphylococcus aureus to induce subclinical mastitis in dairy cows. The expression of mRNA coding for these proteins was assessed and the presence of M......The objectives were to establish the origin of 2 acute phase proteins in milk during subclinical bovine mastitis and to characterize the relationship between those proteins in milk and blood. Haptoglobin (Hp) and mammary-associated serum amyloid A (M-SAA3) appear in milk during mastitis, whereas Hp...

HpBase: A genome database of a sea urchin, Hemicentrotus pulcherrimus.

Science.gov (United States)

Kinjo, Sonoko; Kiyomoto, Masato; Yamamoto, Takashi; Ikeo, Kazuho; Yaguchi, Shunsuke

2018-04-01

To understand the mystery of life, it is important to accumulate genomic information for various organisms because the whole genome encodes the commands for all the genes. Since the genome of Strongylocentrotus purpratus was sequenced in 2006 as the first sequenced genome in echinoderms, the genomic resources of other North American sea urchins have gradually been accumulated, but no sea urchin genomes are available in other areas, where many scientists have used the local species and reported important results. In this manuscript, we report a draft genome of the sea urchin Hemincentrotus pulcherrimus because this species has a long history as the target of developmental and cell biology in East Asia. The genome of H. pulcherrimus was assembled into 16,251 scaffold sequences with an N50 length of 143 kbp, and approximately 25,000 genes were identified in the genome. The size of the genome and the sequencing coverage were estimated to be approximately 800 Mbp and 100×, respectively. To provide these data and information of annotation, we constructed a database, HpBase (http://cell-innovation.nig.ac.jp/Hpul/). In HpBase, gene searches, genome browsing, and blast searches are available. In addition, HpBase includes the "recipes" for experiments from each lab using H. pulcherrimus. These recipes will continue to be updated according to the circumstances of individual scientists and can be powerful tools for experimental biologists and for the community. HpBase is a suitable dataset for evolutionary, developmental, and cell biologists to compare H. pulcherrimus genomic information with that of other species and to isolate gene information. © 2018 Japanese Society of Developmental Biologists.

175Hp contrarotating homopolar motor design report

Science.gov (United States)

Cannell, Michael J.; Drake, John L.; McConnell, Richard A.; Martino, William R.

1994-06-01

A normally conducting contrarotating homopolar motor has been designed and constructed. The reaction torque, in the outer rotor, from the inner rotor is utilized to produce true contrarotation. The machine utilizes liquid cooled conductors, high performance liquid metal current collectors, and ferrous conductors in the active region. The basic machine output is 175 hp at + or - 1,200 rpm with an input of 4 volts and 35,000 amps.

A NEW DISTANT MILKY WAY GLOBULAR CLUSTER IN THE PAN-STARRS1 3π SURVEY

International Nuclear Information System (INIS)

Laevens, Benjamin P. M.; Martin, Nicolas F.; Sesar, Branimir; Rix, Hans-Walter; Schlafly, Edward F.; Bernard, Edouard J.; Ferguson, Annette M. N.; Slater, Colin T.; Bell, Eric F.; Burgett, William S.; Chambers, Kenneth C.; Denneau, Larry; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Magnier, Eugene A.; Morgan, Jeffrey S.; Sweeney, William E.; Draper, Peter W.; Metcalfe, Nigel; Price, Paul A.

2014-01-01

We present a new satellite in the outer halo of the Galaxy, the first Milky Way satellite found in the stacked photometric catalog of the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1) Survey. From follow-up photometry obtained with WFI on the MPG/ESO 2.2 m telescope, we argue that the object, located at a heliocentric distance of 145 ± 17 kpc, is the most distant Milky Way globular cluster yet known. With a total magnitude of M V = –4.3 ± 0.2 and a half-light radius of 20 ± 2 pc, it shares the properties of extended globular clusters found in the outer halo of our Galaxy and the Andromeda galaxy. The discovery of this distant cluster shows that the full spatial extent of the Milky Way globular cluster system has not yet been fully explored

NO EVIDENCE FOR INTERMEDIATE-MASS BLACK HOLES IN GLOBULAR CLUSTERS: STRONG CONSTRAINTS FROM THE JVLA

International Nuclear Information System (INIS)

Strader, Jay; Chomiuk, Laura; Maccarone, Thomas J.; Miller-Jones, James C. A.; Seth, Anil C.; Heinke, Craig O.; Sivakoff, Gregory R.

2012-01-01

With a goal of searching for accreting intermediate-mass black holes (IMBHs), we report the results of ultra-deep Jansky Very Large Array radio continuum observations of the cores of three Galactic globular clusters: M15, M19, and M22. We reach rms noise levels of 1.5-2.1 μJy beam –1 at an average frequency of 6 GHz. No sources are observed at the center of any of the clusters. For a conservative set of assumptions about the properties of the accretion, we set 3σ upper limits on IMBHs from 360 to 980 M ☉ . These limits are among the most stringent obtained for any globular cluster. They add to a growing body of work that suggests either (1) IMBHs ∼> 1000 M ☉ are rare in globular clusters or (2) when present, IMBHs accrete in an extraordinarily inefficient manner.

No Evidence for Intermediate-mass Black Holes in Globular Clusters: Strong Constraints from the JVLA

Science.gov (United States)

Strader, Jay; Chomiuk, Laura; Maccarone, Thomas J.; Miller-Jones, James C. A.; Seth, Anil C.; Heinke, Craig O.; Sivakoff, Gregory R.

2012-05-01

With a goal of searching for accreting intermediate-mass black holes (IMBHs), we report the results of ultra-deep Jansky Very Large Array radio continuum observations of the cores of three Galactic globular clusters: M15, M19, and M22. We reach rms noise levels of 1.5-2.1 μJy beam-1 at an average frequency of 6 GHz. No sources are observed at the center of any of the clusters. For a conservative set of assumptions about the properties of the accretion, we set 3σ upper limits on IMBHs from 360 to 980 M ⊙. These limits are among the most stringent obtained for any globular cluster. They add to a growing body of work that suggests either (1) IMBHs >~ 1000 M ⊙ are rare in globular clusters or (2) when present, IMBHs accrete in an extraordinarily inefficient manner.

pH dependence of the kinetics of interfacial tension changes during protein adsorption from sessile droplets on FEP-Teflon

NARCIS (Netherlands)

VanderVegt, W; Norde, W; VanderMei, HC; Busscher, HJ

Interfacial tension changes during protein adsorption at both the solid-liquid and the liquid-vapor interface were measured simultaneously by ADSA-P from sessile droplets of protein solutions on fluoroethylenepropylene-Teflon. Four globular proteins of similar size, viz. lysozyme, ribonuclease,

HP-67 calculator programs for thermodynamic data and phase diagram calculations

International Nuclear Information System (INIS)

Brewer, L.

1978-01-01

This report is a supplement to a tabulation of the thermodynamic and phase data for the 100 binary systems of Mo with the elements from H to Lr. The calculations of thermodynamic data and phase equilibria were carried out from 5000 0 K to low temperatures. This report presents the methods of calculation used. The thermodynamics involved is rather straightforward and the reader is referred to any advanced thermodynamic text. The calculations were largely carried out using an HP-65 programmable calculator. In this report, those programs are reformulated for use with the HP-67 calculator; great reduction in the number of programs required to carry out the calculation results

TGF-β mimic proteins form an extended gene family in the murine parasite Heligmosomoides polygyrus.

Science.gov (United States)

Smyth, Danielle J; Harcus, Yvonne; White, Madeleine P J; Gregory, William F; Nahler, Janina; Stephens, Ian; Toke-Bjolgerud, Edward; Hewitson, James P; Ivens, Alasdair; McSorley, Henry J; Maizels, Rick M

2018-04-01

We recently reported the discovery of a new parasite-derived protein that functionally mimics the immunosuppressive cytokine transforming growth factor (TGF)-β. The Heligmosomoides polygyrus TGF-β Mimic (Hp-TGM) shares no homology to any TGF-β family member, however it binds the mammalian TGF-β receptor and induces expression of Foxp3, the canonical transcription factor of both mouse and human regulatory T cells. Hp-TGM consists of five atypical Complement Control Protein (CCP, Pfam 00084) domains, each lacking certain conserved residues and 12-15 amino acids longer than the 60-70 amino acids consensus domain, but with a recognizable 3-cysteine, tryptophan, cysteine motif. We now report on the identification of a family of nine related Hp-TGM homologues represented in the secreted proteome and transcriptome of H. polygyrus. Recombinant proteins from five of the nine new TGM members were tested for TGF-β activity, but only two were functionally active in an MFB-F11 reporter assay, and by the induction of T cell Foxp3 expression. Sequence comparisons reveal that proteins with functional activity are similar or identical to Hp-TGM across the first three CCP domains, but more variable in domains 4 and 5. Inactive proteins diverged in all domains, or lacked some domains entirely. Testing truncated versions of Hp-TGM confirmed that domains 1-3 are essential for full activity in vitro, while domains 4 and 5 are not required. Further studies will elucidate whether these latter domains fulfill other functions in promoting host immune regulation during infection and if the more divergent family members play other roles in immunomodulation. Copyright © 2018. Published by Elsevier Ltd.

Analysis of long-range correlation in sequences data of proteins

OpenAIRE

ADRIANA ISVORAN; LAURA UNIPAN; DANA CRACIUN; VASILE MORARIU

2007-01-01

The results presented here suggest the existence of correlations in the sequence data of proteins. 32 proteins, both globular and fibrous, both monomeric and polymeric, were analyzed. The primary structures of these proteins were treated as time series. Three spatial series of data for each sequence of a protein were generated from numerical correspondences between each amino acid and a physical property associated with it, i.e., its electric charge, its polar character and its dipole moment....

An AO-assisted Variability Study of Four Globular Clusters

Science.gov (United States)

Salinas, R.; Contreras Ramos, R.; Strader, J.; Hakala, P.; Catelan, M.; Peacock, M. B.; Simunovic, M.

2016-09-01

The image-subtraction technique applied to study variable stars in globular clusters represented a leap in the number of new detections, with the drawback that many of these new light curves could not be transformed to magnitudes due to severe crowding. In this paper, we present observations of four Galactic globular clusters, M 2 (NGC 7089), M 10 (NGC 6254), M 80 (NGC 6093), and NGC 1261, taken with the ground-layer adaptive optics module at the SOAR Telescope, SAM. We show that the higher image quality provided by SAM allows for the calibration of the light curves of the great majority of the variables near the cores of these clusters as well as the detection of new variables, even in clusters where image-subtraction searches were already conducted. We report the discovery of 15 new variables in M 2 (12 RR Lyrae stars and 3 SX Phe stars), 12 new variables in M 10 (11 SX Phe and 1 long-period variable), and 1 new W UMa-type variable in NGC 1261. No new detections are found in M 80, but previous uncertain detections are confirmed and the corresponding light curves are calibrated into magnitudes. Additionally, based on the number of detected variables and new Hubble Space Telescope/UVIS photometry, we revisit a previous suggestion that M 80 may be the globular cluster with the richest population of blue stragglers in our Galaxy. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Effects of the dietary amount and source of protein, resistance training and anabolic-androgenic steroids on body weight and lipid profile of rats.

Science.gov (United States)

Aparicio, V A; Sánchez, C; Ortega, F B; Nebot, E; Kapravelou, G; Porres, J M; Aranda, P

2013-01-01

Dietary protein amount and source, hypertrophy resistance training (RT) and anabolicandrogenic steroids (AAS) may affect body weight and plasma and hepatic lipid profile. 157 adult male Wistar rats were randomly distributed in 16 experimental groups resulting in: normal-protein (NP) or high-protein (HP) diets, whey or soy-protein diets, with or without RT and with or without AAS, for 3 months. Final body weight was lower in the RT and AAS groups compared to sedentary and non- AAS groups, respectively (all, pweight of rats that performed RT or ingested a HP diet (all, p<0.05). HDL-cholesterol was higher when RT was combined with HP diets (p=0.010) or non-AAS and when HP diets were combined with non-AAS (both,p<0.001). Groups that combined RT with non-AAS administration obtained the lowest hepatic TAG (p<0.05). Among all the interventions tested, AAS was the factor that most negatively affected plasma and hepatic lipid profile, whereas HP diets and RT could benefit lipid profile, especially when combined. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

The effect of microfiltration on color, flavor, and functionality of 80% whey protein concentrate.

Science.gov (United States)

Qiu, Y; Smith, T J; Foegeding, E A; Drake, M A

2015-09-01

The residual annatto colorant in fluid Cheddar cheese whey is bleached to provide a neutral-colored final product. Currently, hydrogen peroxide (HP) and benzoyl peroxide are used for bleaching liquid whey. However, previous studies have shown that chemical bleaching causes off-flavor formation, mainly due to lipid oxidation and protein degradation. The objective of this study was to evaluate the efficacy of microfiltration (MF) on norbixin removal and to compare flavor and functionality of 80% whey protein concentrate (WPC80) from MF whey to WPC80 from whey bleached with HP or lactoperoxidase (LP). Cheddar cheese whey was manufactured from colored, pasteurized milk. The fluid whey was pasteurized and fat separated. Liquid whey was subjected to 4 different treatments: control (no bleaching; 50°C, 1 h), HP (250 mg of HP/kg; 50°C, 1 h), and LP (20 mg of HP/kg; 50°C, 1 h), or MF (microfiltration; 50°C, 1 h). The treated whey was then ultrafiltered, diafiltered, and spray-dried to 80% concentrate. The entire experiment was replicated 3 times. Proximate analyses, color, functionality, descriptive sensory and instrumental volatile analysis were conducted on WPC80. The MF and HP- and LP-bleached WPC80 displayed a 39.5, 40.9, and 92.8% norbixin decrease, respectively. The HP and LP WPC80 had higher cardboard flavors and distinct cabbage flavor compared with the unbleached and MF WPC80. Volatile compound results were consistent with sensory results. The HP and LP WPC80 were higher in lipid oxidation compounds (especially heptanal, hexanal, pentanal, 1-hexen-3-one, 2-pentylfuran, and octanal) compared with unbleached and MF WPC80. All WPC80 had >85% solubility across the pH range of 3 to 7. The microstructure of MF gels determined by confocal laser scanning showed an increased protein particle size in the gel network. MF WPC80 also had larger storage modulus values, indicating higher gel firmness. Based on bleaching efficacy comparable to chemical bleaching with HP

Course 12: Proteins: Structural, Thermodynamic and Kinetic Aspects

Science.gov (United States)

Finkelstein, A. V.

1 Introduction 2 Overview of protein architectures and discussion of physical background of their natural selection 2.1 Protein structures 2.2 Physical selection of protein structures 3 Thermodynamic aspects of protein folding 3.1 Reversible denaturation of protein structures 3.2 What do denatured proteins look like? 3.3 Why denaturation of a globular protein is the first-order phase transition 3.4 "Gap" in energy spectrum: The main characteristic that distinguishes protein chains from random polymers 4 Kinetic aspects of protein folding 4.1 Protein folding in vivo 4.2 Protein folding in vitro (in the test-tube) 4.3 Theory of protein folding rates and solution of the Levinthal paradox

A Visual Language for Protein Design

KAUST Repository

Cox, Robert Sidney

2017-02-08

As protein engineering becomes more sophisticated, practitioners increasingly need to share diagrams for communicating protein designs. To this end, we present a draft visual language, Protein Language, that describes the high-level architecture of an engineered protein with easy-to draw glyphs, intended to be compatible with other biological diagram languages such as SBOL Visual and SBGN. Protein Language consists of glyphs for representing important features (e.g., globular domains, recognition and localization sequences, sites of covalent modification, cleavage and catalysis), rules for composing these glyphs to represent complex architectures, and rules constraining the scaling and styling of diagrams. To support Protein Language we have implemented an extensible web-based software diagram tool, Protein Designer, that uses Protein Language in a

A Visual Language for Protein Design

KAUST Repository

Cox, Robert Sidney; McLaughlin, James Alastair; Grunberg, Raik; Beal, Jacob; Wipat, Anil; Sauro, Herbert M.

2017-01-01

As protein engineering becomes more sophisticated, practitioners increasingly need to share diagrams for communicating protein designs. To this end, we present a draft visual language, Protein Language, that describes the high-level architecture of an engineered protein with easy-to draw glyphs, intended to be compatible with other biological diagram languages such as SBOL Visual and SBGN. Protein Language consists of glyphs for representing important features (e.g., globular domains, recognition and localization sequences, sites of covalent modification, cleavage and catalysis), rules for composing these glyphs to represent complex architectures, and rules constraining the scaling and styling of diagrams. To support Protein Language we have implemented an extensible web-based software diagram tool, Protein Designer, that uses Protein Language in a

BVRI CCD photometry of the globular cluster NGC 2808

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.; Alvarado, F.; Wenderoth, E.

1990-01-01

As a part of a continuing program, CCD color-magnitude diagrams are presented for the bright globular cluster NGC 2808 in the four colors comprising BVRI. From a comparison of four different CMDs with theoretical isochrones, an age of 16 + or - 2 Gyr is obtained, assuming a value for Fe/H near -1.3. 28 refs

Light-fuelled transport of large dendrimers and proteins.

Science.gov (United States)

Koskela, Jenni E; Liljeström, Ville; Lim, Jongdoo; Simanek, Eric E; Ras, Robin H A; Priimagi, Arri; Kostiainen, Mauri A

2014-05-14

This work presents a facile water-based supramolecular approach for light-induced surface patterning. The method is based upon azobenzene-functionalized high-molecular weight triazine dendrimers up to generation 9, demonstrating that even very large globular supramolecular complexes can be made to move in response to light. We also demonstrate light-fuelled macroscopic movements in native biomolecules, showing that complexes of apoferritin protein and azobenzene can effectively form light-induced surface patterns. Fundamentally, the results establish that thin films comprising both flexible and rigid globular particles of large diameter can be moved with light, whereas the presented material concepts offer new possibilities for the yet marginally explored biological applications of azobenzene surface patterning.

From Globular Clusters to Tidal Dwarfs: Structure Formation in Tidal Tails

Science.gov (United States)

Knierman, K.; Hunsberger, S.; Gallagher, S.; Charlton, J.; Whitmore, B.; Hibbard, J.; Kundu, A.; Zaritsky, D.

1999-12-01

Galaxy interactions trigger star formation in tidal debris. How does this star formation depend on the local and global physical conditions? Using WFPC2/HST images, we investigate the range of structure within tidal tails of four classic ``Toomre Sequence'' mergers: NGC 4038/9 (``Antennae''), NGC 7252 (``Atoms for Peace''), NGC 3921, and NGC 3256. These tails contain a variety of stellar associations with sizes from globular clusters up to dwarf Irregulars. We explore whether there is a continuum between the two extremes. Our eight fields sample seven tidal tails at a variety of stages in the evolutionary sequence. Some of these tails are rich in HI while others are HI poor. Large tidal dwarfs are embedded in three of the tails. Using V and I WFPC2 images, we measure luminosities and colors of substructures within the tidal tails. The properties of globular cluster candidates in the tails will be contrasted with those of the hundreds of young clusters in the central regions of these mergers. We address whether globular clusters form and survive in the tidal tails and whether tidal dwarfs are composed of only young stars. By comparing the properties of structures in the tails of the four mergers with different ages, we examine systematic evolution of structure along the evolutionary sequence and as a function of HI content. We acknowledge support from NASA through STScI, and from NSF for an REU supplement for Karen Knierman.

Nonconforming h-p spectral element methods for elliptic problems

Indian Academy of Sciences (India)

In [6,7,13,14] h-p spectral element methods for solving elliptic boundary value problems on polygonal ... Let M denote the number of corner layers and W denote the number of degrees of .... β is given by Theorem 2.2 of [3] which can be stated.

A study on directional resistivity logging-while-drilling based on self-adaptive hp-FEM

Science.gov (United States)

Liu, Dejun; Li, Hui; Zhang, Yingying; Zhu, Gengxue; Ai, Qinghui

2014-12-01

Numerical simulation of resistivity logging-while-drilling (LWD) tool response provides guidance for designing novel logging instruments and interpreting real-time logging data. In this paper, based on self-adaptive hp-finite element method (hp-FEM) algorithm, we analyze LWD tool response against model parameters and briefly illustrate geosteering capabilities of directional resistivity LWD. Numerical simulation results indicate that the change of source spacing is of obvious influence on the investigation depth and detecting precision of resistivity LWD tool; the change of frequency can improve the resolution of low-resistivity formation and high-resistivity formation. The simulation results also indicate that the self-adaptive hp-FEM algorithm has good convergence speed and calculation accuracy to guide the geologic steering drilling and it is suitable to simulate the response of resistivity LWD tools.

Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide.

Science.gov (United States)

Smith, Tucker J; Foegeding, E Allen; Drake, MaryAnne

2015-10-01

Whey protein is a highly functional food ingredient used in a wide variety of applications. A large portion of fluid whey produced in the United States is derived from Cheddar cheese manufacture and contains annatto (norbixin), and therefore must be bleached. The objective of this study was to compare sensory and functionality differences between whey protein isolate (WPI) bleached by benzoyl peroxide (BP) or hydrogen peroxide (HP). HP and BP bleached WPI and unbleached controls were manufactured in triplicate. Descriptive sensory analysis and gas chromatography-mass spectrometry were conducted to determine flavor differences between treatments. Functionality differences were evaluated by measurement of foam stability, protein solubility, SDS-PAGE, and effect of NaCl concentration on gelation relative to an unbleached control. HP bleached WPI had higher concentrations of lipid oxidation and sulfur containing volatile compounds than both BP and unbleached WPI (P protein loss at pH 4.6 of WPI decreased by bleaching with either hydrogen peroxide or benzoyl peroxide (P whey with either BP or HP resulted in protein degradation, which likely contributed to functionality differences. These results demonstrate that bleaching has flavor effects as well as effects on many of the functionality characteristics of whey proteins. Whey protein isolate (WPI) is often used for its functional properties, but the effect of oxidative bleaching chemicals on the functional properties of WPI is not known. This study identifies the effects of hydrogen peroxide and benzoyl peroxide on functional and flavor characteristics of WPI bleached by hydrogen and benzoyl peroxide and provides insights for the product applications which may benefit from bleaching. © 2015 Institute of Food Technologists®

Structural insights into the globular tails of the human type v myosins Myo5a, Myo5b, And Myo5c.

Directory of Open Access Journals (Sweden)

Hana Velvarska

Full Text Available Vertebrate type V myosins (MyoV Myo5a, Myo5b, and Myo5c mediate transport of several different cargoes. All MyoV paralogs bind to cargo complexes mainly by their C-terminal globular domains. In absence of cargo, the globular domain of Myo5a inhibits its motor domain. Here, we report low-resolution SAXS models for the globular domains from human Myo5a, Myo5b, and Myo5c, which suggest very similar overall shapes of all three paralogs. We determined the crystal structures of globular domains from Myo5a and Myo5b, and provide a homology model for human Myo5c. When we docked the Myo5a crystal structure into a previously published electron microscopy density of the autoinhibited full-length Myo5a, only one domain orientation resulted in a good fit. This structural arrangement suggests the participation of additional region of the globular domain in autoinhibition. Quantification of the interaction of the Myo5a globular domain with its motor complex revealed a tight binding with dissociation half-life in the order of minutes, suggesting a rather slow transition between the active and inactive states.

Physicochemical properties of calcium silicate-based formulations MTA Repair HP and MTA Vitalcem.

Science.gov (United States)

Guimarães, Bruno Martini; Prati, Carlo; Duarte, Marco Antonio Hungaro; Bramante, Clovis Monteiro; Gandolfi, Maria Giovanna

2018-04-05

This study aimed to analyze the following physicochemical properties: radiopacity, final setting time, calcium release, pH change, solubility, water sorption, porosity, surface morphology, and apatite-forming ability of two calcium silicate-based materials. We tested MTA Repair HP and MTA Vitalcem in comparison with conventional MTA, analyzing radiopacity and final setting time. Water absorption, interconnected pores and apparent porosity were measured after 24-h immersion in deionized water at 37°C. Calcium and pH were tested up to 28 d in deionized water. We analyzed data using two-way ANOVA with Student-Newman-Keuls tests (pcalcium release at 28 d (pcalcium phosphate on their surface after 28 d in HBSS. MTA Repair HP and MTA Vitalcem had extended alkalinizing activity and calcium release that favored calcium phosphate nucleation. The presence of the plasticizer in MTA HP might increase its solubility and porosity. The radiopacifier calcium tungstate can be used to replace bismuth oxide.

Carbon nanotubes-assisted polyacrylamide gel electrophoresis for enhanced separation of human serum proteins and application in liverish diagnosis.

Science.gov (United States)

Jiang, Fubin; Wang, Yanan; Hu, Xinfang; Shao, Na; Na, Na; Delanghe, Joris R; Ouyang, Jin

2010-11-01

The application of pore-gradient polyacrylamide gel electrophoresis (PG-PAGE) incorporated with carbon nanotube modified by Triton X-100 and carboxylation so as to improve the separation of human serum proteins is reported. The novel PG-PAGE was made by adding water-soluble single-walled carbon nanotubes (CNTs) when preparing the polyacrylamide gel. Significant improvements in separation of complement C3 protein and haptoglobin (Hp) in human serum were achieved. It was estimated that the interactions between the hydrophilic groups on the proteins and the surface of the CNTs result in different adsorption kinetics of complement C3 and Hp subtype on the nanoparticles incorporated in the gel, thus enhancing the separation of the two proteins in serum. This new CNT matrix-assisted PG-PAGE method for enhanced separation of complement C3 and Hp in human serum was successfully applied to distinguish the samples from liverish patients and healthy people.

Protein Tunnels: The Case of Urease Accessory Proteins.

Science.gov (United States)

Musiani, Francesco; Gioia, Dario; Masetti, Matteo; Falchi, Federico; Cavalli, Andrea; Recanatini, Maurizio; Ciurli, Stefano

2017-05-09

Transition metals are both essential micronutrients and limited in environmental availability. The Ni(II)-dependent urease protein, the most efficient enzyme known to date, is a paradigm for studying the strategies that cells use to handle an essential, yet toxic, metal ion. Urease is a virulence factor of several human pathogens, in addition to decreasing the efficiency of soil organic nitrogen fertilization. Ni(II) insertion in the urease active site is performed through the action of three essential accessory proteins: UreD, UreF, and UreG. The crystal structure of the UreD-UreF-UreG complex from the human pathogen Helicobacter pylori (HpUreDFG) revealed the presence of tunnels that cross the entire length of both UreF and UreD, potentially able to deliver Ni(II) ions from UreG to apo-urease. Atomistic molecular dynamics simulations performed on the HpUreDFG complex in explicit solvent and at physiological ionic conditions demonstrate the stability of these protein tunnels in solution and provide insights on the trafficking of water molecules inside the tunnels. The presence of different alternative routes across the identified tunnels for Ni(II) ions, water molecules, and carbonate ions, all involved in urease activation, is highlighted here, and their potential role in the urease activation mechanism is discussed.

Susceptibility of the tomato mutant high pigment-2dg (hp-2dg) to Orobanche spp. infection.

Science.gov (United States)

López-Ráez, Juan Antonio; Charnikhova, Tatsiana; Mulder, Patrick; Kohlen, Wouter; Bino, Raoul; Levin, Ilan; Bouwmeester, Harro

2008-08-13

The consumption of natural products with potential health benefits has been continuously growing, and enhanced pigmentation is of major economic importance in fruits and vegetables. The tomato hp-2 ( dg ) is an important mutant line that has been introgressed into commercial tomato cultivars marketed as lycopene rich tomatoes (LRT) because of their enhanced fruit pigmentation, attributed to higher levels of carotenoids, including lycopene. Strigolactones are signaling compounds that mediate host finding in root parasitic plants and are biosynthetically derived from carotenoids. Considering the high carotenoid content of the hp-2 ( dg ) mutant, we studied its susceptibility to the root parasite Orobanche. In a field experiment, the average number of Orobanche aegyptiaca plants growing on hp-2 ( dg ) was surprisingly significantly reduced compared with its isogenic wild-type counterpart. In vitro assays and LC-MS/MS analysis showed that this reduction was associated with a lower production of strigolactones, which apparently renders the high-carotenoid hp-2 ( dg ) mutant less susceptible to Orobanche.

High-Protein Intake during Weight Loss Therapy Eliminates the Weight-Loss-Induced Improvement in Insulin Action in Obese Postmenopausal Women

OpenAIRE

Gordon I. Smith; Jun Yoshino; Shannon C. Kelly; Dominic N. Reeds; Adewole Okunade; Bruce W. Patterson; Samuel Klein; Bettina Mittendorfer

2016-01-01

High-protein (HP) intake during weight loss (WL) therapy is often recommended because it reduces the loss of lean tissue mass. However, HP intake could have adverse effects on metabolic function, because protein ingestion reduces postprandial insulin sensitivity. In this study, we compared the effects of ∼10% WL with a hypocaloric diet containing 0.8 g protein/kg/day and a hypocaloric diet containing 1.2 g protein/kg/day on muscle insulin action in postmenopausal women with obesity. We found ...

The effects of increased dietary protein yogurt snack in the afternoon on appetite control and eating initiation in healthy women.

Science.gov (United States)

Ortinau, Laura C; Culp, Julie M; Hoertel, Heather A; Douglas, Steve M; Leidy, Heather J

2013-06-06

A large portion of daily intake comes from snacking. One of the increasingly common, healthier snacks includes Greek-style yogurt, which is typically higher in protein than regular yogurt. This study evaluated whether a 160 kcal higher-protein (HP) Greek-style yogurt snack improves appetite control, satiety, and delays subsequent eating compared to an isocaloric normal protein (NP) regular yogurt in healthy women. This study also identified the factors that predict the onset of eating. Thirty-two healthy women (age: 27 ± 2y; BMI: 23.0 ± 0.4 kg/m2) completed the acute, randomized crossover-design study. On separate days, participants came to our facility to consume a standardized lunch followed by the consumption of the NP (5.0 g protein) or HP (14.0 g protein) yogurt at 3 h post-lunch. Perceived hunger and fullness were assessed throughout the afternoon until dinner was voluntarily requested; ad libitum dinner was then provided. Snacking led to reductions in hunger and increases in fullness. No differences in post-snack perceived hunger or fullness were observed between the NP and HP yogurt snacks. Dinner was voluntarily requested at approximately 2:40 ± 0:05 h post-snack with no differences between the HP vs. NP yogurts. Ad libitum dinner intake was not different between the snacks (NP: 686 ± 33 kcal vs. HP: 709 ± 34 kcal; p = 0.324). In identifying key factors that predict eating initiation, perceived hunger, fullness, and habitual dinner time accounted for 30% of the variability of time to dinner request (r = 0.55; p < 0.001). The additional 9 g of protein contained in the high protein Greek yogurt was insufficient to elicit protein-related improvements in markers of energy intake regulation.

AlignMe—a membrane protein sequence alignment web server

Science.gov (United States)

Stamm, Marcus; Staritzbichler, René; Khafizov, Kamil; Forrest, Lucy R.

2014-01-01

We present a web server for pair-wise alignment of membrane protein sequences, using the program AlignMe. The server makes available two operational modes of AlignMe: (i) sequence to sequence alignment, taking two sequences in fasta format as input, combining information about each sequence from multiple sources and producing a pair-wise alignment (PW mode); and (ii) alignment of two multiple sequence alignments to create family-averaged hydropathy profile alignments (HP mode). For the PW sequence alignment mode, four different optimized parameter sets are provided, each suited to pairs of sequences with a specific similarity level. These settings utilize different types of inputs: (position-specific) substitution matrices, secondary structure predictions and transmembrane propensities from transmembrane predictions or hydrophobicity scales. In the second (HP) mode, each input multiple sequence alignment is converted into a hydrophobicity profile averaged over the provided set of sequence homologs; the two profiles are then aligned. The HP mode enables qualitative comparison of transmembrane topologies (and therefore potentially of 3D folds) of two membrane proteins, which can be useful if the proteins have low sequence similarity. In summary, the AlignMe web server provides user-friendly access to a set of tools for analysis and comparison of membrane protein sequences. Access is available at http://www.bioinfo.mpg.de/AlignMe PMID:24753425

Dynamic factors affecting gaseous ligand binding in an artificial oxygen transport protein.

Science.gov (United States)

Zhang, Lei; Andersen, Eskil M E; Khajo, Abdelahad; Magliozzo, Richard S; Koder, Ronald L

2013-01-22

We report the functional analysis of an artificial hexacoordinate oxygen transport protein, HP7, which operates via a mechanism similar to that of human neuroglobin and cytoglobin: the destabilization of one of two heme-ligating histidine residues. In the case of HP7, this is the result of the coupling of histidine side chain ligation with the burial of three charged glutamate residues on the same helix. Here we compare gaseous ligand binding, including rates, affinities, and oxyferrous state lifetimes, of both heme binding sites in HP7. We find that despite the identical sequence of helices in both binding sites, there are differences in oxygen affinity and oxyferrous state lifetime that may be the result of differences in the freedom of motion imposed by the candelabra fold on the two sites of the protein. We further examine the effect of mutational removal of the buried glutamates on function. Heme iron in the ferrous state of this mutant is rapidly oxidized when exposed to oxygen. Compared to that of HP7, the distal histidine affinity is increased by a 22-fold decrease in the histidine ligand off rate. Electron paramagnetic resonance comparison of these ferric hemoproteins demonstrates that the mutation increases the level of disorder at the heme binding site. Nuclear magnetic resonance-detected deuterium exchange demonstrates that the mutation greatly increases the degree of penetration of water into the protein core. The inability of the mutant protein to bind oxygen may be due to an increased level of water penetration, the large decrease in binding rate caused by the increase in distal histidine affinity, or a combination of the two factors. Together, these data underline the importance of the control of protein dynamics in the design of functional artificial proteins.

Effects of Acids, Bases, and Heteroatoms on Proximal Radial Distribution Functions for Proteins.

Science.gov (United States)

Nguyen, Bao Linh; Pettitt, B Montgomery

2015-04-14

The proximal distribution of water around proteins is a convenient method of quantifying solvation. We consider the effect of charged and sulfur-containing amino acid side-chain atoms on the proximal radial distribution function (pRDF) of water molecules around proteins using side-chain analogs. The pRDF represents the relative probability of finding any solvent molecule at a distance from the closest or surface perpendicular protein atom. We consider the near-neighbor distribution. Previously, pRDFs were shown to be universal descriptors of the water molecules around C, N, and O atom types across hundreds of globular proteins. Using averaged pRDFs, a solvent density around any globular protein can be reconstructed with controllable relative error. Solvent reconstruction using the additional information from charged amino acid side-chain atom types from both small models and protein averages reveals the effects of surface charge distribution on solvent density and improves the reconstruction errors relative to simulation. Solvent density reconstructions from the small-molecule models are as effective and less computationally demanding than reconstructions from full macromolecular models in reproducing preferred hydration sites and solvent density fluctuations.

Effect of tissue scaffold topography on protein structure monitored by fluorescence spectroscopy.

Science.gov (United States)

Portugal, Carla A M; Truckenmüller, Roman; Stamatialis, Dimitrios; Crespo, João G

2014-11-10

The impact of surface topography on the structure of proteins upon adhesion was assessed through non-invasive fluorescence monitoring. This study aimed at obtaining a better understanding about the role of protein structural status on cell-scaffold interactions. The changes induced upon adsorption of two model proteins with different geometries, trypsin (globular conformation) and fibrinogen (rod-shaped conformation) on poly-l-lactic acid (PLLA) scaffolds with different surface topographies, flat, fibrous and surfaces with aligned nanogrooves, were assessed by fluorescence spectroscopy monitoring, using tryptophan as structural probe. Hence, the maximum emission blue shift and the increase of fluorescence anisotropy observed after adsorption of globular and rod-like shaped proteins on surfaces with parallel nanogrooves were ascribed to more intense protein-surface interactions. Furthermore, the decrease of fluorescence anisotropy observed upon adsorption of proteins to scaffolds with fibrous morphology was more significant for rod-shaped proteins. This effect was associated to the ability of these proteins to adjust to curved surfaces. The additional unfolding of proteins induced upon adsorption on scaffolds with a fibrous morphology may be the reason for better cell attachment there, promoting an easier access of cell receptors to initially hidden protein regions (e.g. RGDS sequence), which are known to have a determinant role in cell attaching processes. Copyright © 2014 Elsevier B.V. All rights reserved.

Isolation of eukaryotic ribosomal proteins. Purification and characterization of 60 S ribosomal subunit proteins L3, L6, L7', L8, L10, L15, L17, L18, L19, L23', L25, L27', L28, L29, L31, L32, L34, L35, L36, L36', and L37'.

Science.gov (United States)

Tsurugi, K; Collatz, E; Todokoro, K; Wool, I G

1977-06-10

The proteins of the large subunit of rat liver ribosomes were separated into seven groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5. Twenty-one proteins (L3, L6, L7', L8, L10, L15, L17, L18, L19, L23', L25, L27', L28, L29, L31, L32, L34, L35, L36, L36', and L37') were isolated from three groups (C60, E60, and F60) by ion exchange chromatography on carboxymethycellulose and by filtration through Sephadex. The amount of protein obtained varied from 0.3 to 25 mg. Nine of the proteins (L6, L8, L18, L27', L28, L29, L34, L36, and L36') had no detectable contamination: the impurities in the others were no greater than 9%. The molecular weight of the proteins was estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate; the amino acid composition was determined.

THE IMPACT OF CONTAMINATED RR LYRAE/GLOBULAR CLUSTER PHOTOMETRY ON THE DISTANCE SCALE

Energy Technology Data Exchange (ETDEWEB)

Majaess, D.; Turner, D.; Lane, D. [Department of Astronomy and Physics, Saint Mary' s University, Halifax, NS B3H 3C3 (Canada); Gieren, W., E-mail: dmajaess@ap.smu.ca [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, CL Concepcion (Chile)

2012-06-10

RR Lyrae variables and the stellar constituents of globular clusters are employed to establish the cosmic distance scale and age of the universe. However, photometry for RR Lyrae variables in the globular clusters M3, M15, M54, M92, NGC 2419, and NGC 6441 exhibit a dependence on the clustercentric distance. For example, variables and stars positioned near the crowded high-surface brightness cores of the clusters may suffer from photometric contamination, which invariably affects a suite of inferred parameters (e.g., distance, color excess, absolute magnitude, etc.). The impetus for this study is to mitigate the propagation of systematic uncertainties by increasing awareness of the pernicious impact of contaminated and radial-dependent photometry.

Changes in UCP expression in tissues of Zucker rats fed diets with different protein content.

Science.gov (United States)

Masanés, R M; Yubero, P; Rafecas, I; Remesar, X

2002-09-01

The effect of dietary protein content on the uncoupling proteins (UCP) 1, 2 and 3 expression in a number of tissues of Zucker lean and obese rats was studied. Thirty-day-old male Zucker lean (Fa/?) and obese (fa/fa) rats were fed on hyperproteic (HP, 30% protein), standard (RD, 17% protein) or hypoproteic (LP, 9% protein) diets ad libitum for 30 days. Although dietary protein intake affected the weights of individual muscles in lean and obese animals, these weights were similar. In contrast, huge differences were observed in brown adipose tissue (BAT) and liver weights. Lean rats fed on the LP diet generally increased UCP expression, whereas the HP group had lower values. Obese animals, HP and LP groups showed higher UCP expression in muscles, with slight differences in BAT and lower values for UCP3 in subcutaneous adipose tissue. The mean values of UCP expression in BAT of obese rats were lower than in their lean counterpart, whereas the expression in skeletal muscle was increased. Thus, expression of UCPs can be modified by dietary protein content, in lean and obese rats. A possible thermogenic function of UCP3 in muscle and WAT in obese rats must be taken into account.

M31 GLOBULAR CLUSTER STRUCTURES AND THE PRESENCE OF X-RAY BINARIES

International Nuclear Information System (INIS)

Agar, J. R. R.; Barmby, P.

2013-01-01

The Andromeda galaxy, M31, has several times the number of globular clusters found in the Milky Way. It contains a correspondingly larger number of low-mass X-ray binaries (LMXBs) associated with globular clusters, and as such can be used to investigate the cluster properties that lead to X-ray binary formation. The best tracer of the spatial structure of M31 globulars is the high-resolution imaging available from the Hubble Space Telescope (HST), and we have used HST data to derive structural parameters for 29 LMXB-hosting M31 globular clusters. These measurements are combined with structural parameters from the literature for a total of 41 (of 50 known) LMXB clusters and a comparison sample of 65 non-LMXB clusters. Structural parameters measured in blue bandpasses are found to be slightly different (smaller core radii and higher concentrations) than those measured in red bandpasses; this difference is enhanced in LMXB clusters and could be related to stellar population differences. Clusters with LMXBs show higher collision rates for their mass compared to clusters without LMXBs, and collision rates estimated at the core radius show larger offsets than rates estimated at the half-light radius. These results are consistent with the dynamical formation scenario for LMXBs. A logistic regression analysis finds that, as expected, the probability of a cluster hosting an LMXB increases with increasing collision rate and proximity to the galaxy center. The same analysis finds that probability of a cluster hosting an LMXB decreases with increasing cluster mass at a fixed collision rate, although we caution that this could be due to sample selection effects. Metallicity is found to be a less important predictor of LMXB probability than collision rate, mass, or distance, even though LMXB clusters have a higher metallicity on average. This may be due to the interaction of location and metallicity: a sample of M31 LMXBs with a greater range in galactocentric distance would

Ethnicity/culture modulates the relationships of the haptoglobin (Hp) 1-1 phenotype with cognitive function in older individuals with type 2 diabetes.

Science.gov (United States)

Guerrero-Berroa, Elizabeth; Ravona-Springer, Ramit; Heymann, Anthony; Schmeidler, James; Hoffman, Hadas; Preiss, Rachel; Koifmann, Keren; Greenbaum, Lior; Levy, Andrew; Silverman, Jeremy M; Leroith, Derek; Sano, Mary; Schnaider-Beeri, Michal

2016-05-01

The haptoglobin (Hp) genotype has been associated with cognitive function in type 2 diabetes. Because ethnicity/culture has been associated with both cognitive function and Hp genotype frequencies, we examined whether it modulates the association of Hp with cognitive function. This cross-sectional study evaluated 787 cognitively normal older individuals (>65 years of age) with type 2 diabetes participating in the Israel Diabetes and Cognitive Decline study. Interactions in two-way analyses of covariance compared Group (Non-Ashkenazi versus Ashkenazi Jews) on the associations of Hp phenotype (Hp 1-1 versus non- Hp 1-1) with five cognitive outcome measures. The primary control variables were age, gender, and education. Compared with Ashkenazi Jews, non-Ashkenazi Jews with the Hp 1-1 phenotype had significantly poorer cognitive function than non-Hp 1-1 in the domains of Attention/Working Memory (p = 0.035) and Executive Function (p = 0.023), but not in Language/Semantic Categorization (p = 0.432), Episodic Memory (p = 0.268), or Overall Cognition (p = 0.082). After controlling for additional covariates (type 2 diabetes-related characteristics, cardiovascular risk factors, Mini-mental State Examination, and extent of depressive symptoms), Attention/Working Memory (p = 0.038) and Executive Function (p = 0.013) remained significant. Older individuals from specific ethnic/cultural backgrounds with the Hp 1-1 phenotype may benefit more from treatment targeted at decreasing or halting the detrimental effects of Hp 1-1 on the brain. Future studies should examine differential associations of Hp 1-1 and cognitive impairment, especially for groups with high prevalence of both, such as African-Americans and Hispanics. Copyright © 2015 John Wiley & Sons, Ltd.

LITHIUM-RICH GIANTS IN GLOBULAR CLUSTERS

Energy Technology Data Exchange (ETDEWEB)

Kirby, Evan N.; Cohen, Judith G. [California Institute of Technology, 1200 E. California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Guhathakurta, Puragra [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Zhang, Andrew J. [The Harker School, 500 Saratoga Avenue, San Jose, CA 95129 (United States); Hong, Jerry [Palo Alto High School, 50 Embarcadero Road, Palo Alto, CA, 94301 (United States); Guo, Michelle [Stanford University, 450 Serra Mall, Stanford, CA 94305 (United States); Guo, Rachel [Irvington High School, 41800 Blacow Road, Fremont, CA 94538 (United States); Cunha, Katia [Observatório Nacional, São Cristóvão Rio de Janeiro (Brazil)

2016-03-10

Although red giants deplete lithium on their surfaces, some giants are Li-rich. Intermediate-mass asymptotic giant branch (AGB) stars can generate Li through the Cameron–Fowler conveyor, but the existence of Li-rich, low-mass red giant branch (RGB) stars is puzzling. Globular clusters are the best sites to examine this phenomenon because it is straightforward to determine membership in the cluster and to identify the evolutionary state of each star. In 72 hours of Keck/DEIMOS exposures in 25 clusters, we found four Li-rich RGB and two Li-rich AGB stars. There were 1696 RGB and 125 AGB stars with measurements or upper limits consistent with normal abundances of Li. Hence, the frequency of Li-richness in globular clusters is (0.2 ± 0.1)% for the RGB, (1.6 ± 1.1)% for the AGB, and (0.3 ± 0.1)% for all giants. Because the Li-rich RGB stars are on the lower RGB, Li self-generation mechanisms proposed to occur at the luminosity function bump or He core flash cannot explain these four lower RGB stars. We propose the following origin for Li enrichment: (1) All luminous giants experience a brief phase of Li enrichment at the He core flash. (2) All post-RGB stars with binary companions on the lower RGB will engage in mass transfer. This scenario predicts that 0.1% of lower RGB stars will appear Li-rich due to mass transfer from a recently Li-enhanced companion. This frequency is at the lower end of our confidence interval.

The deposition of globular polypyrrole and polypyrrole nanotubes on cotton textile

Czech Academy of Sciences Publication Activity Database

Bober, Patrycja; Stejskal, Jaroslav; Šeděnková, Ivana; Trchová, Miroslava; Martinková, L.; Marek, J.

2015-01-01

Roč. 356, 30 November (2015), s. 737-741 ISSN 0169-4332 R&D Projects: GA TA ČR(CZ) TE01020022 Institutional support: RVO:61389013 Keywords : conducting textile * cotton * globular polypyrrole Subject RIV: CG - Electrochemistry Impact factor: 3.150, year: 2015

[Relationships between the enrichment of ETBF, Fn, Hp in intestinal and colorectal cancer].

Science.gov (United States)

Zhang, J; Lu, X L; Zhao, G; Shi, H T; Geng, Y; Zhong, W T; Dong, L

2018-02-23

Objective: To explore relationships between the enrichment of ETBF, Fn, Hp in feces, tissues and colorectal cancer. Methods: Feces, lesion tissue and adjacent tissue from 24 patients with colorectal cancer and 31 patients with adenomas were collected, and we collected Feces and tissue of 20 healthy control persons. Then the copy numbers of enterotoxigenic B. fragilis (ETBF), Fusobacterium nucleatum (Fn) and Helicobacter pylori (Hp) were determined by quantitative real-time PCR. Immunohistochemical method was used to examine the expression intensity of EGFR and p53, and the relationships between different expression intensity of EGFR, p53 and the numbers of three bacterias. Results: In the feces, copy numbers of ETBF and Fn were as follous: colorectal cancer group>adenomas group>healthy control group ( P healthy control group ( P healthy control group ( P adenomas group>healthy control group ( P healthy control group ( P healthy control group ( P bacteria in the lesion tissue and the adjacent tissue had no significant difference. This happened both in colorectal cancer group and adenomas group. The different expression intensity of EGFR, p53 and the number of three bacteria showed no obviously statistical correlation( P >0.05). Conclusion: Adenomatous polyp and colorectal cancer patients show high enrichment of ETBF, Fn and Hp in both feces and tissues. ETBF, Fn and Hp probably contribute to the development of adenomatous polyp and colorectal cancer. Trial registration Chinese Clinical Trial Registry, ChiCTR-BOC-17012509.

Structural, Mechanical, Anisotropic, and Thermal Properties of AlAs in oC12 and hP6 Phases under Pressure

Directory of Open Access Journals (Sweden)

Wei Zhang

2018-05-01

Full Text Available The structural, mechanical, anisotropic, and thermal properties of oC12-AlAs and hP6-AlAs under pressure have been investigated by employing first-principles calculations based on density functional theory. The elastic constants, bulk modulus, shear modulus, Young’s modulus, B/G ratio, and Poisson’s ratio for oC12-AlAs and hP6-AlAs have been systematically investigated. The results show that oC12-AlAs and hP6-AlAs are mechanically stable within the considered pressure. Through the study of lattice constants (a, b, and c with pressure, we find that the incompressibility of oC12-AlAs and hP6-AlAs is the largest along the c-axis. At 0 GPa, the bulk modulus B of oC12-AlAs, hP6-AlAs, and diamond-AlAs are 76 GPa, 75 GPa, and 74 Gpa, respectively, indicating that oC12-AlAs and hP6-AlAs have a better capability of resistance to volume than diamond-AlAs. The pressure of transition from brittleness to ductility for oC12-AlAs and hP6-AlAs are 1.21 GPa and 2.11 GPa, respectively. The anisotropy of Young’s modulus shows that oC12-AlAs and hP6-AlAs have greater isotropy than diamond-AlAs. To obtain the thermodynamic properties of oC12-AlAs and hP6-AlAs, the sound velocities, Debye temperature, and minimum thermal conductivity at considered pressure were investigated systematically. At ambient pressure, oC12-AlAs (463 K and hP6-AlAs (471 K have a higher Debye temperature than diamond-AlAs (433 K. At T = 300 K, hP6-AlAs (0.822 W/cm·K−1 has the best thermal conductivity of the three phases, and oC12-AlAs (0.809 W/cm·K−1 is much close to diamond-AlAs (0.813 W/cm·K−1.

Determination of effective dose in anisotropic gamma radiation fields: application of dosimeters calibrated in terms of Hp(10)

International Nuclear Information System (INIS)

Chumak, V. V.; Bakhanova, E. V.

2003-01-01

In this presentation authors deals with determination of effective dose in anisotropic gamma radiation fields. It was conclude that: - Straightforward application of Hp(10) as surrogate for E may not work under certain conditions; - Partial data on behavior of E and Hp(10) for different dosimeters allow to estimate E/Hp(10) conversion coefficients for any particular composite source; - In practical situations, anisotropy of workplace fields may be measured by six- collimator device assessing contribution to a dose from six orthogonal directions; - Reasonably conservative conversion coefficients may be assessed for given energy spectrum and degree of anisotropy of workplace fields; - For strongly anisotropic fields multiple dosimetry approach gives the best estimate of E comparing to plain Hp(10) readouts or integral conversion coefficients

An object-oriented decomposition of the adaptive-hp finite element method

Energy Technology Data Exchange (ETDEWEB)

Wiley, J.C.

1994-12-13

Adaptive-hp methods are those which use a refinement control strategy driven by a local error estimate to locally modify the element size, h, and polynomial order, p. The result is an unstructured mesh in which each node may be associated with a different polynomial order and which generally require complex data structures to implement. Object-oriented design strategies and languages which support them, e.g., C++, help control the complexity of these methods. Here an overview of the major classes and class structure of an adaptive-hp finite element code is described. The essential finite element structure is described in terms of four areas of computation each with its own dynamic characteristics. Implications of converting the code for a distributed-memory parallel environment are also discussed.

Deep CCD photometry in globular clusters III. M15

International Nuclear Information System (INIS)

Fahlman, G.G.; Richer, H.B.; Vandenberg, D.A.

1985-01-01

CCD photometry in U, B, and V is presented for a 5' x 3' field in the globular cluster M15. The location of the main sequence in the color-magnitude diagram is found here to be significantly bluer than previous studies have indicated. The luminosity function of the cluster is studied down to V = 22.8 (Mroughly-equal7.5) and shown to be consistent with a power-law mass function, n(M) = QM/sup -alpha/ with α = 2.5 +- 1.0, to the limit of our data. The field star population brighter than V = 21.5, is examined in some detail. There appears to be about 50% more stars belonging to the disk in the field as compared with the Bahcall-Soneira standard galaxy model. The reddening to the cluster is found to be E(B-V) = 0.11 +- 0.04 from nine bright field stars. A new value for the ultraviolet excess of the cluster main-sequence stars is obtained, delta(0.6) = 0.25 +- 0.02, and confirms the well-known fact that M15 is among the metal poorest of the globular clusters

An Archival Search For Young Globular Clusters in Galaxies

Science.gov (United States)

Whitmore, Brad

1995-07-01

One of the most intriguing results from HST has been the discovery of ultraluminous star clusters in interacting and merging galaxies. These clusters have the luminosities, colors, and sizes that would be expected of young globular clusters produced by the interaction. We propose to use the data in the HST Archive to determine how prevalent this phenomena is, and to determine whether similar clusters are produced in other environments. Three samples will be extracted and studied in a systematic and consistent manner: 1} interacting and merging galaxies, 2} starburst galaxies, 3} a control sample of ``normal'' galaxies. A preliminary search of the archives shows that there are at least 20 galaxies in each of these samples, and the number will grow by about 50 observations become available. The data will be used to determine the luminosity function, color histogram , spatial distribution, and structural properties of the clusters using the same techniques employed in our study of NGC 7252 {``Atoms -for-Peace'' galaxy} and NGC 4038/4039 {``The Antennae''}. Our ultimate goals are: 1} to understand how globular clusters form, and 2} to use the clusters as evolutionary tracers to unravel the histories of interacting galaxies.

Long-term weight maintenance and cardiovascular risk factors are not different following weight loss on carbohydrate-restricted diets high in either monounsaturated fat or protein in obese hyperinsulinaemic men and women.

Science.gov (United States)

Keogh, Jennifer B; Luscombe-Marsh, Natalie D; Noakes, Manny; Wittert, Gary A; Clifton, Peter M

2007-02-01

The aim of this study was to determine after 52 weeks whether advice to follow a lower carbohydrate diet, either high in monounsaturated fat or low fat, high in protein had differential effects in a free-living community setting. Following weight loss on either a high monounsaturated fat, standard protein (HMF; 50 % fat, 20 % protein (67 g/d), 30 % carbohydrate) or a high protein, moderate fat (HP) (40 % protein (136 g/d), 30 % fat, 30 % carbohydrate) energy-restricted diet (6000 kJ/d) subjects were asked to maintain the same dietary pattern without intensive dietary counselling for the following 36 weeks. Overall weight loss was 6.2 (SD 7.3) kg (P loss at the end of the study were sex, age and reported percentage energy from protein (R2 0.22, P loss and improvement in cardiovascular risk factors with no adverse effects of a high monounsaturated fat diet.

Deep radio synthesis images of globular clusters

International Nuclear Information System (INIS)

Kulkarni, S.R.; Goss, W.M.; Wolszczan, A.; Middleditch, J.

1990-01-01

Results are reported from a program of high-resolution and high-sensitivity imaging of globular clusters at 20 cm. The findings indicate that there is not a large number of pulsars in compact binaries which have escaped detection in single-dish pulse searches. Such binaries have been postulated to result from tidal captures of single main-sequence stars. It is suggested that most tidal captures involving neutron stars ultimately result in the formation of a spun-up single pulsar and the complete disruption of the main-sequence star. 27 refs

On a Weak Discrete Maximum Principle for hp-FEM

Czech Academy of Sciences Publication Activity Database

Šolín, Pavel; Vejchodský, Tomáš

-, č. 209 (2007), s. 54-65 ISSN 0377-0427 R&D Projects: GA ČR(CZ) GA102/05/0629 Institutional research plan: CEZ:AV0Z20570509; CEZ:AV0Z10190503 Keywords : discrete maximum principle * hp-FEM Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.943, year: 2007

Variable Stars in Large Magellanic Cloud Globular Clusters. II. NGC 1786

Science.gov (United States)

Kuehn, Charles A.; Smith, Horace A.; Catelan, Márcio; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2012-12-01

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series B-V photometric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is seen in most globular clusters. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

ZFP36L1 and ZFP36L2 inhibit cell proliferation in a cyclin D-dependent and p53-independent manner

OpenAIRE

Suk, Fat-Moon; Chang, Chi-Ching; Lin, Ren-Jye; Lin, Shyr-Yi; Liu, Shih-Chen; Jau, Chia-Feng; Liang, Yu-Chih

2018-01-01

ZFP36 family members include ZFP36, ZFP36L1, and ZFP36L2, which belong to CCCH-type zinc finger proteins with two tandem zinc finger (TZF) regions. Whether ZFP36L1 and ZFP36L2 have antiproliferative activities similar to that of ZFP36 is unclear. In this study, when ZFP36L1 or ZFP36L2 was overexpressed in T-REx-293 cells, cell proliferation was dramatically inhibited and the cell cycle was arrested at the G1 phase. The levels of cell-cycle-related proteins, including cyclin B, cyclin D, cycli...

Enteral β-hydroxy-β-methylbutyrate supplementation increases protein synthesis in skeletal muscle of neonatal pigs

Science.gov (United States)

Kao, Michelle; Columbus, Daniel A.; Suryawan, Agus; Steinhoff-Wagner, Julia; Hernandez-Garcia, Adriana; Nguyen, Hanh V.; Fiorotto, Marta L.

2016-01-01

Many low-birth weight infants are at risk for poor growth due to an inability to achieve adequate protein intake. Administration of the amino acid leucine stimulates protein synthesis in skeletal muscle of neonates. To determine the effects of enteral supplementation of the leucine metabolite β-hydroxy-β-methylbutyrate (HMB) on protein synthesis and the regulation of translation initiation and degradation pathways, overnight-fasted neonatal pigs were studied immediately (F) or fed one of five diets for 24 h: low-protein (LP), high-protein (HP), or LP diet supplemented with 4 (HMB4), 40 (HMB40), or 80 (HMB80) μmol HMB·kg body wt−1·day−1. Cell replication was assessed from nuclear incorporation of BrdU in the longissimus dorsi (LD) muscle and jejunum crypt cells. Protein synthesis rates in LD, gastrocnemius, rhomboideus, and diaphragm muscles, lung, and brain were greater in HMB80 and HP and in brain were greater in HMB40 compared with LP and F groups. Formation of the eIF4E·eIF4G complex and S6K1 and 4E-BP1 phosphorylation in LD, gastrocnemius, and rhomboideus muscles were greater in HMB80 and HP than in LP and F groups. Phosphorylation of eIF2α and eEF2 and expression of SNAT2, LAT1, MuRF1, atrogin-1, and LC3-II were unchanged. Numbers of BrdU-positive myonuclei in the LD were greater in HMB80 and HP than in the LP and F groups; there were no differences in jejunum. The results suggest that enteral supplementation with HMB increases skeletal muscle protein anabolism in neonates by stimulation of protein synthesis and satellite cell proliferation. PMID:27143558

The "Globularization Hypothesis" of the Language-ready Brain as a Developmental Frame for Prosodic Bootstrapping Theories of Language Acquisition.

Science.gov (United States)

Irurtzun, Aritz

2015-01-01

In recent research (Boeckx and Benítez-Burraco, 2014a,b) have advanced the hypothesis that our species-specific language-ready brain should be understood as the outcome of developmental changes that occurred in our species after the split from Neanderthals-Denisovans, which resulted in a more globular braincase configuration in comparison to our closest relatives, who had elongated endocasts. According to these authors, the development of a globular brain is an essential ingredient for the language faculty and in particular, it is the centrality occupied by the thalamus in a globular brain that allows its modulatory or regulatory role, essential for syntactico-semantic computations. Their hypothesis is that the syntactico-semantic capacities arise in humans as a consequence of a process of globularization, which significantly takes place postnatally (cf. Neubauer et al., 2010). In this paper, I show that Boeckx and Benítez-Burraco's hypothesis makes an interesting developmental prediction regarding the path of language acquisition: it teases apart the onset of phonological acquisition and the onset of syntactic acquisition (the latter starting significantly later, after globularization). I argue that this hypothesis provides a developmental rationale for the prosodic bootstrapping hypothesis of language acquisition (cf. i.a. Gleitman and Wanner, 1982; Mehler et al., 1988, et seq.; Gervain and Werker, 2013), which claim that prosodic cues are employed for syntactic parsing. The literature converges in the observation that a large amount of such prosodic cues (in particular, rhythmic cues) are already acquired before the completion of the globularization phase, which paves the way for the premises of the prosodic bootstrapping hypothesis, allowing babies to have a rich knowledge of the prosody of their target language before they can start parsing the primary linguistic data syntactically.

The globularization hypothesis of the language-ready brain as a developmental frame for prosodic bootstrapping theories of language acquisition

Directory of Open Access Journals (Sweden)

Aritz eIrurtzun

2015-12-01

Full Text Available In recent research Boeckx & Benítez-Burraco (2014a,b have advanced the hypothesis that our species-specific language-ready brain should be understood as the outcome of developmental changes that occurred in our species after the split from Neanderthals-Denisovans, which resulted in a more globular braincase configuration in comparison to our closest relatives, who had elongated endocasts. According to these authors, the development of a globular brain is an essential ingredient for the language faculty and in particular, it is the centrality occupied by the thalamus in a globular brain that allows its modulatory or regulatory role, essential for syntactico-semantic computations. Their hypothesis is that the syntactico-semantic capacities arise in humans as a consequence of a process of globularization, which significantly takes place postnatally (cf. Neubauer et al. (2010. In this paper, I show that Boeckx & Benítez-Burraco’s hypothesis makes an interesting developmental prediction regarding the path of language acquisition: it teases apart the onset of phonological acquisition and the onset of syntactic acquisition (the latter starting significantly later, after globularization. I argue that this hypothesis provides a developmental rationale for the prosodic bootstrapping hypothesis of language acquisition (cf. i.a. Gleitman & Wanner (1982; Mehler et al. (1988, et seq.; Gervain & Werker (2013, which claim that prosodic cues are employed for syntactic parsing. The literature converges in the observation that a large amount of such prosodic cues (in particular, rhythmic cues are already acquired before the completion of the globularization phase, which paves the way for the premises of prosodic bootstrapping hypothesis, allowing babies to have a rich knowledge of the prosody of their target language before they can start parsing the primary linguistic data syntactically.

DhHP-6 extends lifespan of Caenorhabditis elegans by enhancing nuclear translocation and transcriptional activity of DAF-16.

Science.gov (United States)

Huang, Lei; Li, Pengfei; Wang, Guan; Guan, Shuwen; Sun, Xiaoli; Wang, Liping

2013-04-01

Earlier studies have demonstrated that Deuterohaemin-AlaHisThrValGluLys (DhHP-6), a novel porphyrin-peptide, increases lifespan and enhances stress resistance of Caenorhabditis elegans. To explore the possible mechanisms, in this study we investigated the roles of SIR-2.1 and DAF-16 in DhHP-6's function using wild-type and various other mutant strains of C. elegans. DhHP-6's effect was dependent upon DAF-16, and it did not extend the lifespan of the loss-of-function daf-16 mutant strain (daf-16(mu86) I). DhHP-6 enhanced DAF-16 translocation from cytoplasm to nuclei; and it increased DAF-16's transcriptional activity, likely by activating the SIR-2.1/DAF-16 complex. DhHP-6's effect was also dependent upon SIR-2.1, and it did not increase the lifespan of the worms with SIR-2.1 deacetylase activity inhibited by niacin amide (SIR-2.1 inhibitor) and SIR-2.1 RNA interference (RNAi). Niacin amide and RNAi increased DAF-16's nuclear localization; but they decreased DAF-16's transcriptional activity, likely by preventing the formation of the SIR-2.1/DAF-16 complex. These results suggest that DhHP-6 extends the lifespan of C. elegans via SIR 2.1 and DAF-16, and they provide new insights into the molecular mechanisms of aging.

Changes in the protein profile of Habanero pepper (Capsicum ...

African Journals Online (AJOL)

2012-06-12

Jun 12, 2012 ... (Capsicum chinense J.) somatic embryos during ... molecular weights to those reported for storage proteins in other .... were isolated by cutting with a razor blade. ... electrophoresis (SDS-PAGE; 5% stacking gel [pH 6.8], 15% running ... Developmental stages correspond to C) globular, D) heart-shaped, ...

Helicobacter pylori-derived Heat shock protein 60 enhances angiogenesis via a CXCR2-mediated signaling pathway

Energy Technology Data Exchange (ETDEWEB)

Lin, Chen-Si [Department of Biological Science and Technology, National Chiao-Tung University, Hsin-Chu, Taiwan (China); School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan (China); He, Pei-Juin; Hsu, Wei-Tung [Department of Biological Science and Technology, National Chiao-Tung University, Hsin-Chu, Taiwan (China); Wu, Ming-Shiang [Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Wu, Chang-Jer [Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan (China); Shen, Hsiao-Wei [Institute of Molecular Medicine and Bioengineering, National Chiao-Tung University, Hsin-Chu, Taiwan (China); Hwang, Chia-Hsiang [Yung-Shin Pharmaceutical Industry Co., Ltd., Tachia, Taichung, Taiwan (China); Lai, Yiu-Kay [Department of Life Science, Institute of Biotechnology, National Tsing Hua University, Hsin-Chu, Taiwan (China); Tsai, Nu-Man [School of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung, Taiwan (China); Liao, Kuang-Wen, E-mail: kitchhen@yahoo.com.tw [Institute of Molecular Medicine and Bioengineering, National Chiao-Tung University, Hsin-Chu, Taiwan (China)

2010-06-25

Helicobacter pylori is a potent carcinogen associated with gastric cancer malignancy. Recently, H. pylori Heat shock protein 60 (HpHSP60) has been reported to promote cancer development by inducing chronic inflammation and promoting tumor cell migration. This study demonstrates a role for HpHSP60 in angiogenesis, a necessary precursor to tumor growth. We showed that HpHSP60 enhanced cell migration and tube formation, but not cell proliferation, in human umbilical vein endothelial cells (HUVECs). HpHSP60 also indirectly promoted HUVEC proliferation when HUVECs were co-cultured with supernatants collected from HpHSP60-treated AGS or THP-1 cells. The angiogenic array showed that HpHSP60 dramatically induced THP-1 cells and HUVECs to produce the chemotactic factors IL-8 and GRO. Inhibition of CXCR2, the receptor for IL-8 and GRO, or downstream PLC{beta}2/Ca2+-mediated signaling, significantly abolished HpHSP60-induced tube formation. In contrast, suppression of MAP K or PI3 K signaling did not affect HpHSP60-mediated tubulogenesis. These data suggest that HpHSP60 enhances angiogenesis via CXCR2/PLC{beta}2/Ca2+ signal transduction in endothelial cells.

Helicobacter pylori-derived Heat shock protein 60 enhances angiogenesis via a CXCR2-mediated signaling pathway

International Nuclear Information System (INIS)

Lin, Chen-Si; He, Pei-Juin; Hsu, Wei-Tung; Wu, Ming-Shiang; Wu, Chang-Jer; Shen, Hsiao-Wei; Hwang, Chia-Hsiang; Lai, Yiu-Kay; Tsai, Nu-Man; Liao, Kuang-Wen

2010-01-01

Helicobacter pylori is a potent carcinogen associated with gastric cancer malignancy. Recently, H. pylori Heat shock protein 60 (HpHSP60) has been reported to promote cancer development by inducing chronic inflammation and promoting tumor cell migration. This study demonstrates a role for HpHSP60 in angiogenesis, a necessary precursor to tumor growth. We showed that HpHSP60 enhanced cell migration and tube formation, but not cell proliferation, in human umbilical vein endothelial cells (HUVECs). HpHSP60 also indirectly promoted HUVEC proliferation when HUVECs were co-cultured with supernatants collected from HpHSP60-treated AGS or THP-1 cells. The angiogenic array showed that HpHSP60 dramatically induced THP-1 cells and HUVECs to produce the chemotactic factors IL-8 and GRO. Inhibition of CXCR2, the receptor for IL-8 and GRO, or downstream PLCβ2/Ca2+-mediated signaling, significantly abolished HpHSP60-induced tube formation. In contrast, suppression of MAP K or PI3 K signaling did not affect HpHSP60-mediated tubulogenesis. These data suggest that HpHSP60 enhances angiogenesis via CXCR2/PLCβ2/Ca2+ signal transduction in endothelial cells.

Effect of low-carbohydrate diets high in either fat or protein on thyroid function, plasma insulin, glucose, and triglycerides in healthy young adults.

Science.gov (United States)

Ullrich, I H; Peters, P J; Albrink, M J

1985-01-01

A low-carbohydrate diet, frequently used for treatment of reactive hypoglycemia, hypertriglyceridemia, and obesity may affect thyroid function. We studied the effects of replacing the deleted carbohydrate with either fat or protein in seven healthy young adults. Subjects were randomly assigned to receive seven days of each of two isocaloric liquid-formula, low-carbohydrate diets consecutively. One diet was high in polyunsaturated fat (HF), with 10%, 55%, and 35% of total calories derived from protein, fat, and carbohydrate, respectively. The other was high in protein (HP) with 35%, 30%, and 35% of total calories derived from protein, fat, and carbohydrate. Fasting blood samples were obtained at baseline and on day 8 of each diet. A meal tolerance test representative of each diet was given on day 7. The triiodothyronine (T3) declined more (P less than .05) following the HF diet than the HP diet (baseline 198 micrograms/dl, HP 138, HF 113). Thyroxine (T4) and reverse T3 (rT3) did not change significantly. Thyroid-stimulating hormone (TSH) declined equally after both diets. The insulin level was significantly higher 30 minutes after the HP meal (148 microU/ml) than after the HF meal (90 microU/ml). The two-hour glucose level for the HP meal was less, 85 mg/dl, than after the HF meal (103 mg/dl). Serum triglycerides decreased more after the HF diet (HF 52 mg/dl, HP 67 mg/dl). Apparent benefits of replacing carbohydrate with polyunsaturated fat rather than protein are less insulin response and less postpeak decrease in blood glucose and lower triglycerides. The significance of the lower T3 level is unknown.

Most Massive Globular Cluster in Our Galaxy

Science.gov (United States)

1994-05-01

Far down in the southern sky, in the constellation of Centaurus, a diffuse spot of light can be perceived with the unaided eye. It may be unimpressive, but when seen through a telescope, it turns out to be a beautiful, dense cluster of innumerable stars [1]. Omega Centauri, as this object is called, is the brightest of its type in the sky. We refer to it as a "globular cluster", due to its symmetric form. It belongs to our Milky Way galaxy and astrophysical investigations have shown that it is located at a distance of about 16,500 light-years (1 light-year = 9,460,000,000,000 km). Nobody knows for sure how many individual stars it contains, but recent estimates run into the millions. Most of these stars are more than 10,000 million years old and it is generally agreed that Omega Centauri has a similar age. Measurements of its motion indicate that Omega Centauri plows through the Milky Way in an elongated orbit. It is not easy to understand how it has managed to keep its stars together during such an extended period. MEASURING STELLAR VELOCITIES IN OMEGA CENTAURI A group of astronomers [2] have recently carried through a major investigation of Omega Centauri. After many nights of observations at the ESO La Silla observatory, they now conclude that not only is this globular cluster the brightest, it is indeed by far the most massive known in the Milky Way. The very time-consuming observations were made during numerous observing sessions over a period of no less than 13 years (1981-1993), with the photoelectric spectrometer CORAVEL mounted on the 1.5-m Danish telescope at La Silla. The CORAVEL instrument (COrelation RAdial VELocities) was built in a joint effort between the Geneva (Switzerland) and Marseilles (France) observatories. It functions according to the cross-correlation technique, by means of which the spectrum of the observed star is compared with a "standard stellar spectrum" [3]. HOW HEAVY IS OMEGA CENTAURI? In the present study, a total of 1701

E+ subgroup PPR protein defective kernel 36 is required for multiple mitochondrial transcripts editing and seed development in maize and Arabidopsis.

Science.gov (United States)

Wang, Gang; Zhong, Mingyu; Shuai, Bilian; Song, Jiandong; Zhang, Jie; Han, Liang; Ling, Huiling; Tang, Yuanping; Wang, Guifeng; Song, Rentao

2017-06-01

Mitochondria are semi-autonomous organelles that are the powerhouse of the cells. Plant mitochondrial RNA editing guided by pentatricopeptide repeat (PPR) proteins is essential for energy production. We identify a maize defective kernel mutant dek36, which produces small and collapsed kernels, leading to embryos and/or seedlings lethality. Seed filling in dek36 is drastically impaired, in line with the defects observed in the organization of endosperm transfer tissue. Positional cloning reveals that DEK36, encoding a mitochondria-targeted E+ subgroup PPR protein, is required for mitochondrial RNA editing at atp4-59, nad7-383 and ccmF N -302, thus resulting in decreased activities of mitochondrial complex I, complex III and complex IV in dek36. Loss-of-function of its Arabidopsis ortholog At DEK36 causes arrested embryo and endosperm development, leading to embryo lethality. At_dek36 also has RNA editing defects in atp4, nad7, ccmF N 1 and ccmF N 2 , but at the nonconserved sites. Importantly, efficiency of all editing sites in ccmF N 1 , ccmF N 2 and rps12 is severely decreased in At_dek36, probably caused by the impairment of their RNA stabilization. These results suggest that the DEK36 orthologue pair are essential for embryo and endosperm development in both maize and Arabidopsis, but through divergent function in regulating RNA metabolism of their mitochondrial targets. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Study of biochemical parameters of CD36 protein and effect of RNA interference on its function

Czech Academy of Sciences Publication Activity Database

Zídková, J.; Kontrová, K.; Sajdok, J.; Káš, J.; Mikulík, Karel; Pěknicová, Jana; Zídek, Václav

2006-01-01

Roč. 7, č. 3 (2006), s. 203-203 ISSN 1567-5688 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50110509; CEZ:AV0Z50520514 Keywords : cd36 protein * spontaneously hypertensive rat * metabolic disorders Subject RIV: EE - Microbiology, Virology Impact factor: 5.875, year: 2006

Water Dynamics in Protein Hydration Shells: The Molecular Origins of the Dynamical Perturbation

Science.gov (United States)

2014-01-01

Protein hydration shell dynamics play an important role in biochemical processes including protein folding, enzyme function, and molecular recognition. We present here a comparison of the reorientation dynamics of individual water molecules within the hydration shell of a series of globular proteins: acetylcholinesterase, subtilisin Carlsberg, lysozyme, and ubiquitin. Molecular dynamics simulations and analytical models are used to access site-resolved information on hydration shell dynamics and to elucidate the molecular origins of the dynamical perturbation of hydration shell water relative to bulk water. We show that all four proteins have very similar hydration shell dynamics, despite their wide range of sizes and functions, and differing secondary structures. We demonstrate that this arises from the similar local surface topology and surface chemical composition of the four proteins, and that such local factors alone are sufficient to rationalize the hydration shell dynamics. We propose that these conclusions can be generalized to a wide range of globular proteins. We also show that protein conformational fluctuations induce a dynamical heterogeneity within the hydration layer. We finally address the effect of confinement on hydration shell dynamics via a site-resolved analysis and connect our results to experiments via the calculation of two-dimensional infrared spectra. PMID:24479585

Biophysics of protein evolution and evolutionary protein biophysics

Science.gov (United States)

Sikosek, Tobias; Chan, Hue Sun

2014-01-01

The study of molecular evolution at the level of protein-coding genes often entails comparing large datasets of sequences to infer their evolutionary relationships. Despite the importance of a protein's structure and conformational dynamics to its function and thus its fitness, common phylogenetic methods embody minimal biophysical knowledge of proteins. To underscore the biophysical constraints on natural selection, we survey effects of protein mutations, highlighting the physical basis for marginal stability of natural globular proteins and how requirement for kinetic stability and avoidance of misfolding and misinteractions might have affected protein evolution. The biophysical underpinnings of these effects have been addressed by models with an explicit coarse-grained spatial representation of the polypeptide chain. Sequence–structure mappings based on such models are powerful conceptual tools that rationalize mutational robustness, evolvability, epistasis, promiscuous function performed by ‘hidden’ conformational states, resolution of adaptive conflicts and conformational switches in the evolution from one protein fold to another. Recently, protein biophysics has been applied to derive more accurate evolutionary accounts of sequence data. Methods have also been developed to exploit sequence-based evolutionary information to predict biophysical behaviours of proteins. The success of these approaches demonstrates a deep synergy between the fields of protein biophysics and protein evolution. PMID:25165599

hp-FEM electromechanical transduction model of ionic polymer metal composites

Czech Academy of Sciences Publication Activity Database

Pugal, D.; Šolín, Pavel; Kim, K.; Aabloo, A.

2014-01-01

Roč. 260, April (2014), s. 135-148 ISSN 0377-0427 R&D Projects: GA ČR(CZ) GAP102/11/0498 Institutional support: RVO:61388998 Keywords : hp-FEM * Nernst-Planck * Poisson Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.266, year: 2014

A Particle Swarm Optimization-Based Approach with Local Search for Predicting Protein Folding.

Science.gov (United States)

Yang, Cheng-Hong; Lin, Yu-Shiun; Chuang, Li-Yeh; Chang, Hsueh-Wei

2017-10-01

The hydrophobic-polar (HP) model is commonly used for predicting protein folding structures and hydrophobic interactions. This study developed a particle swarm optimization (PSO)-based algorithm combined with local search algorithms; specifically, the high exploration PSO (HEPSO) algorithm (which can execute global search processes) was combined with three local search algorithms (hill-climbing algorithm, greedy algorithm, and Tabu table), yielding the proposed HE-L-PSO algorithm. By using 20 known protein structures, we evaluated the performance of the HE-L-PSO algorithm in predicting protein folding in the HP model. The proposed HE-L-PSO algorithm exhibited favorable performance in predicting both short and long amino acid sequences with high reproducibility and stability, compared with seven reported algorithms. The HE-L-PSO algorithm yielded optimal solutions for all predicted protein folding structures. All HE-L-PSO-predicted protein folding structures possessed a hydrophobic core that is similar to normal protein folding.

Effect of antiparkinson drug HP-200 (Mucuna pruriens) on the central monoaminergic neurotransmitters.

Science.gov (United States)

Manyam, Bala V; Dhanasekaran, Muralikrishnan; Hare, Theodore A

2004-02-01

HP-200, which contains Mucuna pruriens endocarp, has been shown to be effective in the treatment of Parkinson's disease. Mucuna pruriens endocarp has also been shown to be more effective compared to synthetic levodopa in an animal model of Parkinson's disease. The present study was designed to elucidate the long-term effect of Mucuna pruriens endocarp in HP-200 on monoaminergic neurotransmitters and its metabolite in various regions of the rat brain. HP-200 at a dose of 2.5, 5.0 or 10.0 g/kg/day was mixed with rat chow and fed daily ad lib to Sprague-Dawley rats (n = 6 for each group) for 52 weeks. Controls (n = 6) received no drug. Random assignment was made for doses and control. The rats were sacrificed at the end of 52 weeks and the neurotransmitters were analyzed in the cortex, hippocampus, substantia nigra and striatum. Oral administration of Mucuna pruriens endocarp in the form of HP-200 had a significant effect on dopamine content in the cortex with no significant effect on levodopa, norepinephrine or dopamine, serotonin, and their metabolites- HVA, DOPAC and 5-HIAA in the nigrostriatal tract. The failure of Mucuna pruriens endocarp to significantly affect dopamine metabolism in the striatonigral tract along with its ability to improve Parkinsonian symptoms in the 6-hydorxydopamine animal model and humans may suggest that its antiparkinson effect may be due to components other than levodopa or that it has an levodopa enhancing effect. Copyright 2004 John Wiley & Sons, Ltd. Copyright 2004 John Wiley & Sons, Ltd.

In silico local structure approach: a case study on outer membrane proteins.

Science.gov (United States)

Martin, Juliette; de Brevern, Alexandre G; Camproux, Anne-Claude

2008-04-01

The detection of Outer Membrane Proteins (OMP) in whole genomes is an actual question, their sequence characteristics have thus been intensively studied. This class of protein displays a common beta-barrel architecture, formed by adjacent antiparallel strands. However, due to the lack of available structures, few structural studies have been made on this class of proteins. Here we propose a novel OMP local structure investigation, based on a structural alphabet approach, i.e., the decomposition of 3D structures using a library of four-residue protein fragments. The optimal decomposition of structures using hidden Markov model results in a specific structural alphabet of 20 fragments, six of them dedicated to the decomposition of beta-strands. This optimal alphabet, called SA20-OMP, is analyzed in details, in terms of local structures and transitions between fragments. It highlights a particular and strong organization of beta-strands as series of regular canonical structural fragments. The comparison with alphabets learned on globular structures indicates that the internal organization of OMP structures is more constrained than in globular structures. The analysis of OMP structures using SA20-OMP reveals some recurrent structural patterns. The preferred location of fragments in the distinct regions of the membrane is investigated. The study of pairwise specificity of fragments reveals that some contacts between structural fragments in beta-sheets are clearly favored whereas others are avoided. This contact specificity is stronger in OMP than in globular structures. Moreover, SA20-OMP also captured sequential information. This can be integrated in a scoring function for structural model ranking with very promising results. (c) 2007 Wiley-Liss, Inc.

Characterization of dry globular proteins and protein fibrils by synchrotron radiation vacuum UV circular dichroism

DEFF Research Database (Denmark)

Nesgaard, Lise W.; Hoffmann, Søren Vrønning; Andersen, Christian Beyschau

2008-01-01

Circular dichroism using synchrotron radiation (SRCD) can extend the spectral range down to approximately 130 nm for dry proteins, potentially providing new structural information. Using a selection of dried model proteins, including alpha-helical, beta-sheet, and mixed-structure proteins, we...... with previously published theoretical calculations related to pi-orbital transitions. We also show that drying does not lead to large changes in the secondary structure and does not induce orientational artifacts. In combination with principal component analysis, our SRCD data allow us to distinguish between two...... different types of protein fibrils, highlighting that bona fide fibrils formed by lysozyme are structurally more similar to the nonclassical fibrillar aggregates formed by the SerADan peptide than with the amyloid formed by alpha-synuclein. Thus, despite the lack of direct structural conclusions...

A period-luminosity relation for Mira variables in globular clusters and its impact on the distance scale

International Nuclear Information System (INIS)

Menzies, J.W.; Whitelock, P.A.

1985-01-01

JHKL photometry is presented for 31 red variables in 15 galactic globular clusters. The photometry of the Mira variables is used to find absolute bolometric magnitudes and an Msub(bol)-log P relation which differs from the one found for LMC Miras. This can be understood only if there is some systematic error in the globular cluster and/or LMC distance scales or if there is some fundamental difference between the cluster Miras and those in the LMC. (author)

Seasonal oscillation of liver-derived hibernation protein complex in the central nervous system of non-hibernating mammals

Science.gov (United States)

Seldin, Marcus M.; Byerly, Mardi S.; Petersen, Pia S.; Swanson, Roy; Balkema-Buschmann, Anne; Groschup, Martin H.; Wong, G. William

2014-01-01

Mammalian hibernation elicits profound changes in whole-body physiology. The liver-derived hibernation protein (HP) complex, consisting of HP-20, HP-25 and HP-27, was shown to oscillate circannually, and this oscillation in the central nervous system (CNS) was suggested to play a role in hibernation. The HP complex has been found in hibernating chipmunks but not in related non-hibernating tree squirrels, leading to the suggestion that hibernation-specific genes may underlie the origin of hibernation. Here, we show that non-hibernating mammals express and regulate the conserved homologous HP complex in a seasonal manner, independent of hibernation. Comparative analyses of cow and chipmunk HPs revealed extensive biochemical and structural conservations. These include liver-specific expression, assembly of distinct heteromeric complexes that circulate in the blood and cerebrospinal fluid, and the striking seasonal oscillation of the HP levels in the blood and CNS. Central administration of recombinant HPs affected food intake in mice, without altering body temperature, physical activity levels or energy expenditure. Our results demonstrate that HP complex is not unique to the hibernators and suggest that the HP-regulated liver–brain circuit may couple seasonal changes in the environment to alterations in physiology. PMID:25079892

Effect of tooth bleaching agents on protein content and mechanical properties of dental enamel.

Science.gov (United States)

Elfallah, Hunida M; Bertassoni, Luiz E; Charadram, Nattida; Rathsam, Catherine; Swain, Michael V

2015-07-01

This study investigated the effect of two bleaching agents, 16% carbamide peroxide (CP) and 35% hydrogen peroxide (HP), on the mechanical properties and protein content of human enamel from freshly extracted teeth. The protein components of control and treated enamel were extracted and examined on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Marked reduction of the protein matrix and random fragmentation of the enamel proteins after bleaching treatments was found. The mechanical properties were analyzed with Vickers indentations to characterize fracture toughness, and nanoindentation to establish enamel hardness, elastic modulus and creep deformation. Results indicate that the hardness and elastic modulus of enamel were significantly reduced after treatment with CP and HP. After bleaching, the creep deformation at maximum load increased and the recovery upon unloading reduced. Crack lengths of CP and HP treated enamel were increased, while fracture toughness decreased. Additionally, the microstructures of fractured and indented samples were examined with field emission gun scanning electron microscopy (FEG-SEM) showing distinct differences in the fracture surface morphology between pre- and post-bleached enamel. In conclusion, tooth bleaching agents can produce detrimental effects on the mechanical properties of enamel, possibly as a consequence of damaging or denaturing of its protein components. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Electrorheological properties of suspensions of hollow globular titanium oxide/polypyrrole particles

Czech Academy of Sciences Publication Activity Database

Sedlačík, M.; Mrlík, M.; Pavlínek, V.; Sáha, P.; Quadrat, Otakar

2012-01-01

Roč. 290, č. 1 (2012), s. 41-48 ISSN 0303-402X R&D Projects: GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : electrorheology * titanium oxide * hollow globular clusters Subject RIV: JI - Composite Materials Impact factor: 2.161, year: 2012

Altering protein surface charge with chemical modification modulates protein–gold nanoparticle aggregation

International Nuclear Information System (INIS)

Jamison, Jennifer A.; Bryant, Erika L.; Kadali, Shyam B.; Wong, Michael S.; Colvin, Vicki L.; Matthews, Kathleen S.; Calabretta, Michelle K.

2011-01-01

Gold nanoparticles (AuNP) can interact with a wide range of molecules including proteins. Whereas significant attention has focused on modifying the nanoparticle surface to regulate protein–AuNP assembly or influence the formation of the protein “corona,” modification of the protein surface as a mechanism to modulate protein–AuNP interaction has been less explored. Here, we examine this possibility utilizing three small globular proteins—lysozyme with high isoelectric point (pI) and established interactions with AuNP; α-lactalbumin with similar tertiary fold to lysozyme but low pI; and myoglobin with a different globular fold and an intermediate pI. We first chemically modified these proteins to alter their charged surface functionalities, and thereby shift protein pI, and then applied multiple methods to assess protein–AuNP assembly. At pH values lower than the anticipated pI of the modified protein, AuNP exposure elicits changes in the optical absorbance of the protein–NP solutions and other properties due to aggregate formation. Above the expected pI, however, protein–AuNP interaction is minimal, and both components remain isolated, presumably because both species are negatively charged. These data demonstrate that protein modification provides a powerful tool for modulating whether nanoparticle–protein interactions result in material aggregation. The results also underscore that naturally occurring protein modifications found in vivo may be critical in defining nanoparticle–protein corona compositions.

Space-time adaptive hp-FEM for problems with traveling sharp fronts

Czech Academy of Sciences Publication Activity Database

Šolín, Pavel; Korous, L.

2013-01-01

Roč. 95, č. 1 (2013), S709-S722 ISSN 0010-485X Institutional support: RVO:61388998 Keywords : adaptive hp-FEM * transient problems * sharp fronts Subject RIV: BA - General Mathematics Impact factor: 1.055, year: 2013

hp Spectral element methods for three dimensional elliptic problems

Indian Academy of Sciences (India)

This is the first of a series of papers devoted to the study of h-p spec- .... element functions defined on mesh elements in the new system of variables with a uni- ... the spectral element functions on these elements and give construction of the stability .... By Hm( ), we denote the usual Sobolev space of integer order m ≥ 0 ...

Acute phase proteins in dogs naturally infected with the Giant Kidney Worm (Dioctophyme renale)

DEFF Research Database (Denmark)

Schmidt, Elizabeth M. S.; Kjelgaard-Hansen, Mads; Thomas, Funmilola

2016-01-01

of nephrectomy on circulating concentrations of select acute phase proteins (APP) such as serum amyloid A (SAA), C-reactive protein (CRP), and haptoglobin(HP). Methods: Nephrectomy was performed in infected dogs and the worms were collected for identification. Blood samples were taken 24 hours before surgery...... the 12 dogs evaluated in this study. Dogs showed significantly increased HP concentrations(P SAA concentrations before surgery, and cortisol concentrations were significantly higher at admission when compared to recovery. No significant correlations were found between the number...

Intraperitoneal administration of the globular adiponectin gene ameliorates diabetic nephropathy in Wistar rats.

Science.gov (United States)

Yuan, Fang; Liu, Ying-Hong; Liu, Fu-You; Peng, You-Ming; Tian, Jun-Wei

2014-06-01

The present study investigated the potential effects of the long-term expression of exogenous adiponectin (ADPN) on normal and diabetic kidneys. Type 2 diabetes mellitus models were induced by high-lipid and high-sucrose feeding plus intraperitoneal injection of streptozotocin. The recombinant plasmid pIRES2-EGFP-gAd, which is able to co-express globular ADPN (gAd) and enhanced green fluorescent protein (EGFP), was intraperitoneally injected into rat models mediated by Lipofectamine. In total, 32 Wistar rats were randomly assigned into four groups: the normal control group, the diabetes group, the diabetes group treated with pIRES2-EGFP-gAd and the diabetes group treated with pIRES2-EGFP. After 12 weeks, serum biochemistry and urine albumin levels were measured. The kidneys were collected to assess the generation of reactive oxygen species (ROS) and the renal pathological changes were observed by light microcopy. The protein expression of endothelial nitric oxide synthase (eNOS), transforming growth factor-β1 (TGF-β1) and phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) were determined by an immunohistochemical staining method and western blot analysis. Intraperitoneal injection of the human gAd gene via Lipofectamine resulted in abundant ADPN protein in the kidney. In the diabetic rats, the delivery of the exogenous gAd gene ameliorated the progression of diabetic nephropathy (DN). ADPN attenuated urine albumin excretion in the diabetic rats. ADPN also mitigated glomerular mesangial expansion, reduced the generation of ROS and prevented interstitial fibrosis. In addition, the expression of gAd inhibited the renal expression of TGF-β1, promoted the protein expression of eNOS and activated the opening of the AMPK signaling pathway in the renal tissues of the diabetic rats. Despite the effects of ADPN on DN being controversial, these observations indicate that the supplementation of ADPN is beneficial in ameliorating DN in rats.

High-protein diet modifies colonic microbiota and luminal environment but not colonocyte metabolism in the rat model: the increased luminal bulk connection

OpenAIRE

LIU, Xinxin; BLOUIN, Jean-Marc; Santacruz, Arlette; Lan, Annaig; Andriamihaja, Mireille; Wilkanowicz, Sabina; Benetti, Pierre-Henri; Tomé, Daniel; Sanz, Yolanda; Blachier, Francois; Davila-Gay, Anne-Marie

2014-01-01

High-protein diets are used for body weight reduction, but consequences on the large intestine ecosystem are poorly known. Here, rats were fed for 15 days with either a normoproteic diet (NP, 14% protein) or a hyperproteic-hypoglucidic isocaloric diet (HP, 53% protein). Cecum and colon were recovered for analysis. Short- and branched-chain fatty acids, as well as lactate, succinate, formate, and ethanol contents, were markedly increased in the colonic luminal contents of HP rats (P < 0.05 or ...

The effects of increased dietary protein yogurt snack in the afternoon on appetite control and eating initiation in healthy women

Science.gov (United States)

2013-01-01

Background A large portion of daily intake comes from snacking. One of the increasingly common, healthier snacks includes Greek-style yogurt, which is typically higher in protein than regular yogurt. This study evaluated whether a 160 kcal higher-protein (HP) Greek-style yogurt snack improves appetite control, satiety, and delays subsequent eating compared to an isocaloric normal protein (NP) regular yogurt in healthy women. This study also identified the factors that predict the onset of eating. Findings Thirty-two healthy women (age: 27 ± 2y; BMI: 23.0 ± 0.4 kg/m2) completed the acute, randomized crossover-design study. On separate days, participants came to our facility to consume a standardized lunch followed by the consumption of the NP (5.0 g protein) or HP (14.0 g protein) yogurt at 3 h post-lunch. Perceived hunger and fullness were assessed throughout the afternoon until dinner was voluntarily requested; ad libitum dinner was then provided. Snacking led to reductions in hunger and increases in fullness. No differences in post-snack perceived hunger or fullness were observed between the NP and HP yogurt snacks. Dinner was voluntarily requested at approximately 2:40 ± 0:05 h post-snack with no differences between the HP vs. NP yogurts. Ad libitum dinner intake was not different between the snacks (NP: 686 ± 33 kcal vs. HP: 709 ± 34 kcal; p = 0.324). In identifying key factors that predict eating initiation, perceived hunger, fullness, and habitual dinner time accounted for 30% of the variability of time to dinner request (r = 0.55; p < 0.001). Conclusions The additional 9 g of protein contained in the high protein Greek yogurt was insufficient to elicit protein-related improvements in markers of energy intake regulation. PMID:23742659

Cold-set globular protein gels: Interactions, structure and rheology as a function of protein concentration.

NARCIS (Netherlands)

Alting, A.C.; Hamer, R.J.; Kruif, de C.G.

2003-01-01

We identified the contribution of covalent and noncovalent interactions to the scaling behavior of the structural and rheological properties in a cold gelling protein system. The system we studied consisted of two types of whey protein aggregates, equal in size but different in the amount of

Recent developments in the theory of protein folding: searching for the global energy minimum.

Science.gov (United States)

Scheraga, H A

1996-04-16

Statistical mechanical theories and computer simulation are being used to gain an understanding of the fundamental features of protein folding. A major obstacle in the computation of protein structures is the multiple-minima problem arising from the existence of many local minima in the multidimensional energy landscape of the protein. This problem has been surmounted for small open-chain and cyclic peptides, and for regular-repeating sequences of models of fibrous proteins. Progress is being made in resolving this problem for globular proteins.

Sustained-release of FGF-2 from a hybrid hydrogel of heparin-poloxamer and decellular matrix promotes the neuroprotective effects of proteins after spinal injury

Directory of Open Access Journals (Sweden)

Xu HL

2018-02-01

Full Text Available  He-Lin Xu,1,* Fu-Rong Tian,1,* Jian Xiao,1,* Pian-Pian Chen,1 Jie Xu,1 Zi-Liang Fan,1 Jing-Jing Yang,1 Cui-Tao Lu,1 Ying-Zheng Zhao1,2 1Department of Pharmaceutics, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 2Hainan Medical College, Haikou, China *These authors contributed equally to this work Introduction: The short lifetime of protein-based therapies has largely limited their therapeutic efficacy in injured nervous post-spinal cord injury (post-SCI. Methods: In this study, an affinity-based hydrogel delivery system provided sustained-release of proteins, thereby extending the efficacy of such therapies. The affinity-based hydrogel was constructed using a novel polymer, heparin-poloxamer (HP, as a temperature-sensitive bulk matrix and decellular spinal cord extracellular matrix (dscECM as an affinity depot of drug. By tuning the concentration of HP in formulation, the cold ternary fibroblast growth factor-2 (FGF2-dscECM-HP solution could rapidly gelatinize into a hydrogel at body temperature. Due to the strong affinity for FGF2, hybrid FGF2-dscECM-HP hydrogel enabled sustained-release of encapsulated FGF2 over an extended period in vitro. Results: Compared to free FGF2, it was observed that both neuron functions and tissue morphology after SCI were clearly recovered in rats treated with FGF2-dscECM-HP hydrogel. Moreover, the expression of neurofilament protein and the density of axons were increased after treatment with hybrid FGF2-dscECM-HP. In addition, the neuroprotective effects of FGF2-dscECM-HP were related to inhibition of chronic endoplasmic reticulum stress-induced apoptosis.Conclusion: The results revealed that a hybrid hydrogel system may be a potential carrier to deliver macromolecular proteins to the injured site and enhance the therapeutic effects of proteins.Keywords: spinal cord injury, decellularized extracellular matrix, thermosensitive hydrogel, adsorption, basic fibroblast growth factor

The porcine acute phase response to infection with Actinobacillus pleuropneumoniae. Haptoglobin, C-reactive protein, major acute phase protein and serum amyloid a protein are sensitive indicators of infection

DEFF Research Database (Denmark)