Myostatin inhibitory region of fish (Paralichthys olivaceus) myostatin-1 propeptide.

PubMed

Lee, Sang Beum; Kim, Jeong Hwan; Jin, Deuk-Hee; Jin, Hyung-Joo; Kim, Yong Soo

2016-01-01

Myostatin (MSTN) is a potent negative regulator of skeletal muscle growth, and its activity is suppressed by MSTN propeptide (MSTNpro), the N-terminal part of MSTN precursor cleaved during post-translational MSTN processing. The current study examined which region of flatfish (Paralichthys olivaceus) MSTN-1 propeptide (MSTN1pro) is critical for MSTN inhibition. Six different truncated forms of MSTN1pro containing N-terminal maltose binding protein (MBP) as a fusion partner were expressed in Escherichia coli, and partially purified by an affinity chromatography for MSTN-inhibitory activity examination. Peptides covering different regions of flatfish MSTN1pro were also synthesized for MSTN-inhibitory activity examination. A MBP-fused MSTN1pro region consisting of residues 45-100 had the same MSTN-inhibitory potency as the full sequence flatfish MSTN1pro (residues 23-265), indicating that the region of flatfish MSTN1pro consisting of residues 45-100 is sufficient to maintain the full MSTN-inhibitory capacity. A MBP-fused MSTN1pro region consisting of residues 45-80 (Pro45-80) also showed MSTN-inhibitory activity with a lower potency, and the Pro45-80 demonstrated its MSTN binding capacity in a pull-down assay, indicating that the MSTN-inhibitory capacity of Pro45-80 is due to its binding to MSTN. Flatfish MSTN1pro synthetic peptides covering residues 45-65, 45-70, and 45-80 demonstrated MSTN-inhibitory activities, but not the synthetic peptide covering residues 45-54, indicating that residues 45-65 of flatfish MSTN1pro are essential for MSTN inhibition. In conclusion, current study show that like the mammalian MSTNpro, the MSTN-inhibitory region of flatfish MSTN1pro resides near its N-terminus, and imply that smaller sizes of MSTNpro can be effectively used in various applications designed for MSTN inhibition. Copyright © 2016 Elsevier Inc. All rights reserved.

Hydrogen passivation of n+p and p+n heteroepitaxial InP solar cell structures

NASA Technical Reports Server (NTRS)

Chatterjee, B.; Ringel, S. A.; Hoffman, R., Jr.

1995-01-01

High-efficiency, heteroepitaxial (HE) InP solar cells, grown on GaAs, Si or Ge substrates, are desirable for their mechanically strong, light-weight and radiation-hard properties. However, dislocations, caused by lattice mismatch, currently limit the performance of the HE cells. This occurs through shunting paths across the active photovoltaic junction and by the formation of deep levels. In previous work we have demonstrated that plasma hydrogenation is an effective and stable means to passivate the electrical activity of dislocations in specially designed HE InP test structures. In this work, we present the first report of successful hydrogen passivation in actual InP cell structures grown on GaAs substrates by metalorganic chemical vapor deposition (MOCVD). We have found that a 2 hour exposure to a 13.56 MHz hydrogen plasma at 275 C reduces the deep level concentration in HE n+n InP cell structures from as-grown values of approximately 10(exp 15)/cm(exp -3), down to 1-2 x 10(exp 13)/cm(exp -3). The deep levels in the p-type base region of the cell structure match those of our earlier p-type test structures, which were attributed to dislocations or related point defect complexes. All dopants were successfully reactivated by a 400 C, 5 minute anneal with no detectable activation of deep levels. I-V analysis indicated a subsequent approximately 10 fold decrease in reverse leakage current at -1 volt reverse bias, and no change in the forward biased series resistance of the cell structure which indicates complete reactivation of the n+ emitter. Furthermore, electrochemical C-V profiling indicates greatly enhanced passivation depth, and hence hydrogen diffusion, for heteroepitaxial structures when compared with identically processed homoepitaxial n+p InP structures. An analysis of hydrogen diffusion in dislocated InP will be discussed, along with comparisons of passivation effectiveness for n+p versus p+n heteroepitaxial cell configurations. Preliminary hydrogen

Down-regulation of tissue N:P ratios in terrestrial plants by elevated CO2.

PubMed

Deng, Qi; Hui, Dafeng; Luo, Yiqi; Elser, James; Wang, Ying-ping; Loladze, Irakli; Zhang, Quanfa; Dennis, Sam

2015-12-01

Increasing atmospheric CO2 concentrations generally alter element stoichiometry in plants. However, a comprehensive evaluation of the elevated CO2 impact on plant nitrogen: phosphorus (N:P) ratios and the underlying mechanism has not been conducted. We synthesized the results from 112 previously published studies using meta-analysis to evaluate the effects of elevated CO2 on the N:P ratio of terrestrial plants and to explore the underlying mechanism based on plant growth and soil P dynamics. Our results show that terrestrial plants grown under elevated CO2 had lower N:P ratios in both above- and belowground biomass across different ecosystem types. The response ratio for plant N:P was negatively correlated with the response ratio for plant growth in croplands and grasslands, and showed a stronger relationship for P than for N. In addition, the CO2-induced down-regulation of plant N:P was accompanied by 19.3% and 4.2% increases in soil phosphatase activity and labile P, respectively, and a 10.1% decrease in total soil P. Our results show that down-regulation of plant N:P under elevated CO2 corresponds with accelerated soil P cycling. These findings should be useful for better understanding of terrestrial plant stoichiometry in response to elevated CO2 and of the underlying mechanisms affecting nutrient dynamics under climate change.

Increased cardiogenesis in P19-GFP teratocarcinoma cells expressing the propeptide IGF-1Ea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poudel, Bhawana; Bilbao, Daniel; Sarathchandra, Padmini

2011-12-16

Highlights: Black-Right-Pointing-Pointer In this study, we explored the function of IGF-1Ea propeptide in inducing cardiogenesis of stem cells. Black-Right-Pointing-Pointer IGF-1Ea promoted cardiac mesodermal induction in uncommitted cells. Black-Right-Pointing-Pointer Under differentiation condition, IGF-1Ea increased expression of cardiac differentiation markers. Black-Right-Pointing-Pointer Furthermore, it promoted formation of finely organized sarcomeric structure. Black-Right-Pointing-Pointer IGF-1Ea propeptide may be a good candidate to improve production of cardiomyocytes from pluripotent cells. -- Abstract: The mechanism implicated in differentiation of endogenous cardiac stem cells into cardiomyocytes to regenerate the heart tissue upon an insult remains elusive, limiting the therapeutical goals to exogenous cell injection and/or gene therapy. Wemore » have shown previously that cardiac specific overexpression of the insulin-like growth factor 1 propeptide IGF-1Ea induces beneficial myocardial repair after infarct. Although the mechanism is still under investigation, the possibility that this propeptide may be involved in promoting stem cell differentiation into the cardiac lineage has yet to be explored. To investigate whether IGF-1Ea promote cardiogenesis, we initially modified P19 embryonal carcinoma cells to express IGF-1Ea. Taking advantage of their cardiomyogenic nature, we analyzed whether overexpression of this propeptide affected cardiac differentiation program. The data herein presented showed for the first time that constitutively overexpressed IGF-1Ea increased cardiogenic differentiation program in both undifferentiated and DMSO-differentiated cells. In details, IGF-1Ea overexpression promoted localization of alpha-actinin in finely organized sarcomeric structure compared to control cells and upregulated the cardiac mesodermal marker NKX-2.5 and the ventricular structural protein MLC2v. Furthermore, activated IGF-1 signaling promoted cardiac

n-p Short-Range Correlations from (p,2p+n) Measurements

NASA Astrophysics Data System (ADS)

Tang, A.; Watson, J. W.; Aclander, J.; Alster, J.; Asryan, G.; Averichev, Y.; Barton, D.; Baturin, V.; Bukhtoyarova, N.; Carroll, A.; Gushue, S.; Heppelmann, S.; Leksanov, A.; Makdisi, Y.; Malki, A.; Minina, E.; Navon, I.; Nicholson, H.; Ogawa, A.; Panebratsev, Yu.; Piasetzky, E.; Schetkovsky, A.; Shimanskiy, S.; Zhalov, D.

2003-01-01

We studied the 12C(p,2p+n) reaction at beam momenta of 5.9, 8.0, and 9.0 GeV/c. For quasielastic (p,2p) events pf, the momentum of the knocked-out proton before the reaction, was compared (event by event) with pn, the coincident neutron momentum. For |pn|>kF=0.220 GeV/c (the Fermi momentum) a strong back-to-back directional correlation between pf and pn was observed, indicative of short-range n-p correlations. From pn and pf we constructed the distributions of c.m. and relative motion in the longitudinal direction for correlated pairs. We also determined that 49±13% of events with |pf|>kF had directionally correlated neutrons with |pn|>kF.

Diffusion lengths in irradiated N/P InP-on-Si solar cells

NASA Technical Reports Server (NTRS)

Wojtczuk, Steven; Colerico, Claudia; Summers, Geoffrey P.; Walters, Robert J.; Burke, Edward A.

1996-01-01

Indium phosphide (InP) solar cells were made on silicon (Si) wafers (InP/Si) by to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. Spire has made N/P InP/Si cells of sizes up to 2 cm by 4 cm with beginning-of-life (BOL) AM0 efficiencies over 13% (one-sun, 28C). These InP/Si cells have higher absolute efficiency and power density after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells after a fluence of about 2e15 1 MeV electrons/sq. cm. In this work, we investigate the minority carrier (electron) base diffusion lengths in the N/P InP/Si cells. A quantum efficiency model was constructed for a 12% BOL AM0 N/P InP/Si cell which agreed well with the absolutely measured quantum efficiency and the sun-simulator measured AM0 photocurrent (30.1 mA/sq. cm). This model was then used to generate a table of AM0 photocurrents for a range of base diffusion lengths. AM0 photocurrents were then measured for irradiations up to 7.7e16 1 MeV electrons/sq. cm (the 12% BOL cell was 8% after the final irradiation). By comparing the measured photocurrents with the predicted photocurrents, base diffusion lengths were assigned at each fluence level. A damage coefficient K of 4e-8 and a starting (unirradiated) base electron diffusion length of 0.8 microns fits the data well. The quantum efficiency was measured again at the end of the experiment to verify that the photocurrent predicted by the model (25.5 mA/sq. cm) agreed with the simulator-measured photocurrent after irradiation (25.7 mA/sq. cm).

Neurotrophin Propeptides: Biological Functions and Molecular Mechanisms.

PubMed

Rafieva, Lola M; Gasanov, Eugene V

2016-01-01

Neurotrophins constitute a family of growth factors that play a key role in the regulation of the development and function of the central and peripheral nervous systems. A common feature of all the neurotrophins is their synthesis in cells as long precursors (pre-pro-neurotrophins) that contain an N-terminal signal peptide, a following propeptide and the mature neurotrophin. Although the signal peptide functions have been well studied, the role of neurotrophin propeptides is not so clear. Here, we briefly summarize the biochemistry of neurotrophin propeptides, including their role as folding-assistants for the mature factor and their role in processing and in secretion of neurotrophins. In the main part of the review we summarize our current state of knowledge of the biological activity of neurotrophin propeptides, their possible mechanisms of action, and their potential influence on the activity of the mature neurotrophins.

Search For Anomalous n-p Scattering At 60 eV-140 keV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreh, R.; Block, R. C.; Danon, Y.

2009-01-28

A search for an anomalous n-p scattering from a polyethylene sample (CH{sub 2}) at 8 final energies between 64 eV and 2.5 keV was carried out. The scattering intensities were compared to that from a graphite (C) sample. The results were found to confirm our previous n-p results on H{sub 2}O at a final energy of 24.3 keV where no n-p scattering anomaly was observed. The present results refute all proposed models attempting to explain the occurrence of any n-p scattering anomaly at keV neutron energies.

Nitrogen (N) Deposition Impacts Seedling Growth of Pinus massoniana via N:P Ratio Effects and the Modulation of Adaptive Responses to Low P (Phosphorus)

PubMed Central

Zhang, Yi; Zhou, Zhichun; Yang, Qing

2013-01-01

Background In forest ecosystems with phosphorus (P) deficiency, the impact of atmospheric nitrogen (N) deposition on nutritional traits related to P uptake and P use potentially determines plant growth and vegetation productivity. Methodology/Principal Findings Two N deposition simulations were combined with three soil P conditions (homogeneous P deficiency with evenly low P; heterogeneous P deficiency with low subsoil P and high topsoil P; high P) using four full-sib families of Masson pine (Pinus massoniana). Under homogeneous P deficiency, N had a low effect on growth due to higher N:P ratios, whereas N-sensitive genotypes had lower N:P ratios and greater N sensitivity. The N effect increased under higher P conditions due to increased P concentration and balanced N:P ratios. An N:P threshold of 12.0–15.0 was detected, and growth was increased by N with an N:P ratio ≤ 12.0 and increased by P with an N:P ratio ≥ 15.0. Under homogeneous P deficiency, increased P use efficiency by N deposition improved growth. Under heterogeneous P deficiency, a greater P deficiency under N deposition due to increased N:P ratios induced greater adaptive responses to low P (root acid phosphatase secretion and topsoil root proliferation) and improved P acquisition and growth. Conclusions/Significance N deposition diversely affected seedling growth across different P conditions and genotypes via N:P ratio effects and the modulation of adaptive responses to low P. The positive impact of N on growth was genotype-specific and increased by soil P addition due to balanced N:P ratios. These results indicate the significance of breeding N-sensitive tree genotypes and improving forest soil P status to compensate for increasing N deposition. PMID:24205376

Human dermatosparaxis: a form of Ehlers-Danlos syndrome that results from failure to remove the amino-terminal propeptide of type I procollagen.

PubMed

Smith, L T; Wertelecki, W; Milstone, L M; Petty, E M; Seashore, M R; Braverman, I M; Jenkins, T G; Byers, P H

1992-08-01

Dermatosparaxis is a recessively inherited connective-tissue disorder that results from lack of the activity of type I procollagen N-proteinase, the enzyme that removes the amino-terminal propeptides from type I procollagen. Initially identified in cattle more than 20 years ago, the disorder was subsequently characterized in sheep, cats, and dogs. Affected animals have fragile skin, lax joints, and often die prematurely because of sepsis following avulsion of portions of skin. We recently identified two children with soft, lax, and fragile skin, which, when examined by transmission electron microscopy, contained the twisted, ribbon-like collagen fibrils characteristic of dermatosparaxis. Skin extracts from one child contained collagen precursors with amino-terminal extensions. Cultured fibroblasts from both children failed to cleave the amino-terminal propeptides from the pro alpha 1(I) and pro alpha 2(I) chains in type I procollagen molecules. Extracts of normal cells cleaved to collagen, the type I procollagen synthesized by cells from both children, demonstrating that the enzyme, not the substrate, was defective. These findings distinguish dermatosparaxis from Ehlers-Danlos syndrome type VII, which results from substrate mutations that prevent proteolytic processing of type I procollagen molecules.

Mechanism of Fine-tuning pH Sensors in Proprotein Convertases: IDENTIFICATION OF A pH-SENSING HISTIDINE PAIR IN THE PROPEPTIDE OF PROPROTEIN CONVERTASE 1/3.

PubMed

Williamson, Danielle M; Elferich, Johannes; Shinde, Ujwal

2015-09-18

The propeptides of proprotein convertases (PCs) regulate activation of cognate protease domains by sensing pH of their organellar compartments as they transit the secretory pathway. Earlier experimental work identified a conserved histidine-encoded pH sensor within the propeptide of the canonical PC, furin. To date, whether protonation of this conserved histidine is solely responsible for PC activation has remained unclear because of the observation that various PC paralogues are activated at different organellar pH values. To ascertain additional determinants of PC activation, we analyzed PC1/3, a paralogue of furin that is activated at a pH of ∼5.4. Using biophysical, biochemical, and cell-based methods, we mimicked the protonation status of various histidines within the propeptide of PC1/3 and examined how such alterations can modulate pH-dependent protease activation. Our results indicate that whereas the conserved histidine plays a crucial role in pH sensing and activation of this protease an additional histidine acts as a "gatekeeper" that fine-tunes the sensitivity of the PC1/3 propeptide to facilitate the release inhibition at higher proton concentrations when compared with furin. Coupled with earlier analyses that highlighted the enrichment of the amino acid histidine within propeptides of secreted eukaryotic proteases, our work elucidates how secreted proteases have evolved to exploit the pH of the secretory pathway by altering the spatial juxtaposition of titratable groups to regulate their activity in a spatiotemporal fashion. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

The development of decision limits for the GH-2000 detection methodology using additional insulin-like growth factor-I and amino-terminal pro-peptide of type III collagen assays.

PubMed

Holt, Richard I G; Böhning, Walailuck; Guha, Nishan; Bartlett, Christiaan; Cowan, David A; Giraud, Sylvain; Bassett, E Eryl; Sönksen, Peter H; Böhning, Dankmar

2015-09-01

The GH-2000 and GH-2004 projects have developed a method for detecting GH misuse based on measuring insulin-like growth factor-I (IGF-I) and the amino-terminal pro-peptide of type III collagen (P-III-NP). The objectives were to analyze more samples from elite athletes to improve the reliability of the decision limit estimates, to evaluate whether the existing decision limits needed revision, and to validate further non-radioisotopic assays for these markers. The study included 998 male and 931 female elite athletes. Blood samples were collected according to World Anti-Doping Agency (WADA) guidelines at various sporting events including the 2011 International Association of Athletics Federations (IAAF) World Athletics Championships in Daegu, South Korea. IGF-I was measured by the Immunotech A15729 IGF-I IRMA, the Immunodiagnostic Systems iSYS IGF-I assay and a recently developed mass spectrometry (LC-MS/MS) method. P-III-NP was measured by the Cisbio RIA-gnost P-III-P, Orion UniQ™ PIIINP RIA and Siemens ADVIA Centaur P-III-NP assays. The GH-2000 score decision limits were developed using existing statistical techniques. Decision limits were determined using a specificity of 99.99% and an allowance for uncertainty because of the finite sample size. The revised Immunotech IGF-I - Orion P-III-NP assay combination decision limit did not change significantly following the addition of the new samples. The new decision limits are applied to currently available non-radioisotopic assays to measure IGF-I and P-III-NP in elite athletes, which should allow wider flexibility to implement the GH-2000 marker test for GH misuse while providing some resilience against manufacturer withdrawal or change of assays. Copyright © 2015 John Wiley & Sons, Ltd.

Human dermatosparaxis: a form of Ehlers-Danlos syndrome that results from failure to remove the amino-terminal propeptide of type I procollagen.

PubMed Central

Smith, L T; Wertelecki, W; Milstone, L M; Petty, E M; Seashore, M R; Braverman, I M; Jenkins, T G; Byers, P H

1992-01-01

Dermatosparaxis is a recessively inherited connective-tissue disorder that results from lack of the activity of type I procollagen N-proteinase, the enzyme that removes the amino-terminal propeptides from type I procollagen. Initially identified in cattle more than 20 years ago, the disorder was subsequently characterized in sheep, cats, and dogs. Affected animals have fragile skin, lax joints, and often die prematurely because of sepsis following avulsion of portions of skin. We recently identified two children with soft, lax, and fragile skin, which, when examined by transmission electron microscopy, contained the twisted, ribbon-like collagen fibrils characteristic of dermatosparaxis. Skin extracts from one child contained collagen precursors with amino-terminal extensions. Cultured fibroblasts from both children failed to cleave the amino-terminal propeptides from the pro alpha 1(I) and pro alpha 2(I) chains in type I procollagen molecules. Extracts of normal cells cleaved to collagen, the type I procollagen synthesized by cells from both children, demonstrating that the enzyme, not the substrate, was defective. These findings distinguish dermatosparaxis from Ehlers-Danlos syndrome type VII, which results from substrate mutations that prevent proteolytic processing of type I procollagen molecules. Images Figure 5 Figure 2 Figure 3 Figure 1 Figure 4 Figure 6 PMID:1642226

Electrochemical characterization of p(+)n and n(+)p diffused InP structures

NASA Technical Reports Server (NTRS)

Wilt, David M.; Faur, Maria; Faur, Mircea; Goradia, M.; Vargas-Aburto, Carlos

1993-01-01

The relatively well documented and widely used electrolytes for characterization and processing of Si and GaAs-related materials and structures by electrochemical methods are of little or no use with InP because the electrolytes presently used either dissolve the surface preferentially at the defect areas or form residual oxides and introduce a large density of surface states. Using an electrolyte which was newly developed for anodic dissolution of InP, and was named the 'FAP' electrolyte, accurate characterization of InP related structures including nature and density of surface states, defect density, and net majority carrier concentration, all as functions of depth was performed. A step-by-step optimization of n(+)p and p(+)n InP structures made by thermal diffusion was done using the electrochemical techniques, and resulted in high performance homojunction InP structures.

Radiation resistance and comparative performance of ITO/InP and n/p InP homojunction solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Coutts, T. J.

1988-01-01

The radiation resistance of ITO/InP cells processed by dc magnetron sputtering is compared to that of standard n/p InP and GaAs homojunction cells. After 20 MeV proton irradiations, it is found that the radiation resistance of the present ITO/InP cell is comparable to that of the n/p homojunction InP cell and that both InP cell types have radiation resistances significantly greater than GaAs. The relatively lower radiation resistance, observed at higher fluence, for the InP cell with the deepest junction depth, is attributed to losses in the cells emitter region. Diode parameters obtained from I sub sc - V sub oc plots, data from surface Raman spectrosocpy, and determinations of surface conductivity type are used to investigate the configuration of the ITO/InP cells. It is concluded that these latter cells are n/p homojunctions, the n-region consisting of a disordered layer at the oxide semiconductor.

Radiation resistance and comparative performance of ITO/InP and n/p InP homojunction solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Coutts, T. J.

1988-01-01

The radiation resistance of ITO/InP cells processed by DC magnetron sputtering is compared to that of standard n/p InP and GaAs homojunction cells. After 20 MeV proton irradiations, it is found that the radiation resistance of the present ITO/InP cell is comparable to that of the n/p homojunction InP cell and that both InP cell types have radiation resistance significantly greater than GaAs. The relatively lower radiation resistance, observed at higher fluence, for the InP cell with the deepest junction depth, is attributed to losses in the cells emitter region. Diode parameters obtained from I sub sc - V sub oc plots, data from surface Raman spectroscopy, and determinations of surface conductivity types are used to investigate the configuration of the ITO/InP cells. It is concluded that thesee latter cells are n/p homojunctions, the n-region consisting of a disordered layer at the oxide semiconductor.

A dual channel three-terminal np-LDMOS with both majorities for conduction

NASA Astrophysics Data System (ADS)

Kong, Moufu; Yi, Bo; Zhang, Bingke

2018-02-01

A novel dual channel three-terminal np-LDMOS power device with both electrons and holes for conduction is proposed in this paper. Based on a new approach of inducing a large-signal which is processed by a simple circuit for controlling the gate of p-LDMOS inside the device, the new np-LDMOS only requires one external gate controlling voltage signal that can be performed as an n-LDMOS device. The SOA of the new device is improved in comparison with the n-LDMOS device, since the counteracting of electric flux density produced by the both type of carriers' currents. Furthermore, the specific on-resistance of the np-LDMOS device is reduced by about 19% when comparing with that of the conventional one. The control method and performances of the proposed power device are investigated and authenticated by numerical simulations.

Shifting Foliar N:P Ratios with Experimental Soil Warming in Tussock Tundra

NASA Astrophysics Data System (ADS)

Jasinski, B.; Mack, M. C.; Schuur, E.; Mauritz, M.; Walker, X. J.

2017-12-01

Warming temperatures in the Arctic and boreal ecosystems are currently driving widespread permafrost thaw. Thermokarst is one form of thaw, in which a deepening active soil layer and associated hydrologic changes can lead to increased nutrient availability and shifts in plant community composition. Individual plant species often differ in their ability to access nutrients and adapt to new environmental conditions. While nitrogen (N) is often the nutrient most limiting to Arctic plant communities, the extent to which plant available phosphorus (P) from previously frozen mineral soil may increase as the active layer deepens is still uncertain. To understand the changing relationship between species' uptake of N and P in a thermokarst environment, we assessed foliar N:P ratios from 2015 in two species, a tussock sedge (Eriophorum vaginatum) and a dwarf shrub (Rubus chamaemorus), at a moist acidic tussock tundra experimental passive soil warming site. The passive soil warming treatment increased active layer depth in warmed plots by 35.4 cm (+/- 1.1 cm), an 80% increase over the control plots. E.vaginatum demonstrated a 16.9% decrease (p=0.012, 95% CI [-27.99%, -5.94%]) in foliar N:P ratios in warmed plots, driven mostly by an increase in foliar phosphorus. Foliar N:P ratios of R.chamaemorus showed no significant change. However, foliar samples of R.chamaemorus were significantly enriched in the isotope 15N in soil warming plots (9.9% increase (p=0.002, 95% CI [4.45%, 15.39%])), while the sedge E.vaginatum was slightly depleted. These results suggest that (1) in environments with thawing mineral soil plant available phosphorus may increase more quickly than nitrogen, and (2) that species' uptake strategies and responses to increasing N and P will vary, which has implications for future ecological shifts in thawing ecosystems.

Annealing of irradiated n+p InP buried homojunctions

NASA Technical Reports Server (NTRS)

Walters, Robert J.; Summers, Geoffrey P.; Timmons, M. L.; Venkatasubramanian, R.; Hancock, J. A.; Hills, J. S.

1994-01-01

At the last SPRAT conference, the Naval Research Laboratory (NRL) presented results from two experiments. One studied n+p diffused junction (DJ) InP solar cells, and the other studied n+p shallow homojunction (SHJ) InP mesa diodes grown by metalorganic chemical vapor deposition (MOCVD). The former work showed that a DJ solar cell in which the maximum power P(sub max) had been degraded by nearly 80 percent under irradiation recovered completely under short circuit illumination at 450K. The recovery was accompanied by the removal of all but one of the radiation-induced defect levels. The latter work, on the other hand, showed that the radiation-induced defects in the SHJ diodes did not anneal until the temperature reached 650K. These results suggest that an irradiated DJ solar cell, under illumination, will anneal at a temperature 200K lower than an irradiated SHJ cell. This is an unexpected result considering the similarity of the devices. The goal of the present research is to explain this different behavior. This paper investigates two points which arose from the previous studies. The first point is that the DJ cells were annealed under illumination while the SHJ diodes were annealed without bias. The second point investigated here is that the emitters of the DJ and SHJ devices were significantly different.

Impact of dislocation densities on n+/p and p+/n junction GaAs diodes and solar cells on SiGe virtual substrates

NASA Astrophysics Data System (ADS)

Andre, C. L.; Wilt, D. M.; Pitera, A. J.; Lee, M. L.; Fitzgerald, E. A.; Ringel, S. A.

2005-07-01

Recent experimental measurements have shown that in GaAs with elevated threading dislocation densities (TDDs) the electron lifetime is much lower than the hole lifetime [C. L. Andre, J. J. Boeckl, D. M. Wilt, A. J. Pitera, M. L. Lee, E. A. Fitzgerald, B. M. Keyes, and S. A. Ringel, Appl. Phys. Lett. 84, 3884 (2004)]. This lower electron lifetime suggests an increase in depletion region recombination and thus in the reverse saturation current (J0 for an n+/p diode compared with a p+/n diode at a given TDD. To confirm this, GaAs diodes of both polarities were grown on compositionally graded Ge /Si1-xGex/Si (SiGe) substrates with a TDD of 1×106cm-2. It is shown that the ratio of measured J0 values is consistent with the inverse ratio of the expected lifetimes. Using a TDD-dependent lifetime in solar cell current-voltage models we found that the Voc, for a given short-circuit current, also exhibits a poorer TDD tolerance for GaAs n+/p solar cells compared with GaAs p+/n solar cells. Experimentally, the open-circuit voltage (Voc) for the n+/p GaAs solar cell grown on a SiGe substrate with a TDD of ˜1×106cm-2 was ˜880mV which was significantly lower than the ˜980mV measured for a p+/n GaAs solar cell grown on SiGe at the same TDD and was consistent with the solar cell modeling results reported in this paper. We conclude that p+/n polarity GaAs junctions demonstrate superior dislocation tolerance than n+/p configured GaAs junctions, which is important for optimization of lattice-mismatched III-V devices.

Expression of recombinant myostatin propeptide pPIC9K-Msp plasmid in Pichia pastoris.

PubMed

Du, W; Xia, J; Zhang, Y; Liu, M J; Li, H B; Yan, X M; Zhang, J S; Li, N; Zhou, Z Y; Xie, W Z

2015-12-28

Myostatin propeptide can inhibit the biological activity of myostatin protein and promote muscle growth. To express myostatin propeptide in vitro with a higher biological activity, we performed codon optimization on the sheep myostatin propeptide gene sequence, and mutated aspartic acid-76 to alanine based on the codon usage bias of Pichia pastoris and the enhanced biological activity of myostatin propeptide mutant. Modified myostatin propeptide gene was cloned into the pPIC9K plasmid to form the recombinant plasmid pPIC9K-Msp. Recombinant plasmid pPIC9K-Msp was transformed into Pichia pastoris GS115 by electrotransformation. Transformed cells were screened, and methanol was used to induce expression. SDS-PAGE and western blotting were used to verify the successful expression of myostatin propeptide with biological activity in Pichia pastoris, providing the basis for characterization of this protein.

A comparative study of p(+)n and n(+)p InP solar cells made by a closed ampoule diffusion

NASA Technical Reports Server (NTRS)

Faur, M.; Faur, M.; Flood, D. J.; Weinberg, I.; Brinker, D. J.; Goradia, C.; Fatemi, N.; Goradia, M.; Thesling, W.

1991-01-01

The purpose was to demonstrate the possibility of fabricating thermally diffused p(+)n InP solar cells having high open-circuit voltage without sacrificing the short circuit current. The p(+)n junctions were formed by closed-ampoule diffusion of Cd through a 3 to 5 nm thick anodic or chemical phosphorus-rich oxide cap layer grown on n-InP:S Czochralski LEC grown substrates. For solar cells made by thermal diffusion the p(+)n configuration is expected to have a higher efficiency than the n(+)p configuration. It is predicted that the AM0, BOL efficiencies approaching 19 percent should be readily achieved providing that good ohmic front contacts could be realized on the p(+) emitters of thickness lower than 1 micron.

[Soil N/P ratio distribution characteristics of alpine grassland ecosystem in Qinghai-Tibet Plateau].

PubMed

Wang, Jian-Lin; Zhong, Zhi-Ming; Wang, Zhong-Hong; Chen, Bao-Xiong; Zhang, Xian-Zhou; Shen, Zhen-Xi; Hu, Xing-Xiang; Dacizhuoga

2013-12-01

The distribution characteristics of soil N/P ratio in alpine grassland ecosystem of Qinghai-Tibet Plateau were surveyed by field investigation and laboratory analysis. Horizontally, soil N/ P ratio was generally higher in west and lower in east in a manner of staggered patch distribution, with higher N/P ratios mainly centralized in the hinterland of northern part of Tibet Plateau and in the lake basin area of the northern foot of Himalayas. Significant differences in soil N/P ratio were observed among grassland types and natural transects. Vertically, the distribution of N/P ratio along the soil profile from aboveground to underground among different grass types could be categorized into five patterns, including low-high-low-high, low-high-low, low-high, high-low-high-low, and high-low-high. The N/P ratio showed a significant positive correlation with soil bulk density at 0-20 cm depth, soil water content at 20-30 cm depth, contents of soil available K and total nitrogen, respectively. However, it showed significant negative correlation with soil bulk density at 20-30 cm depth, contents of soil available P and total P, respectively.

Design of high-activity single-atom catalysts via n-p codoping

NASA Astrophysics Data System (ADS)

Wang, Xiaonan; Zhou, Haiyan; Zhang, Xiaoyang; Jia, Jianfeng; Wu, Haishun

2018-03-01

The large-scale synthesis of stable single-atom catalysts (SACs) in experiments remains a significant challenge due to high surface free energy of metal atom. Here, we propose a concise n-p codoping approach, and find it can not only disperse the relatively inexpensive metal, copper (Cu), onto boron (B)-doped graphene, but also result in high-activity SACs. We use CO oxidation on B/Cu codoped graphene as a prototype example, and demonstrate that: (1) a stable SAC can be formed by stronger electrostatic attraction between the metal atom (n-type Cu) and support (p-type B-doped graphene). (2) the energy barrier of the prototype CO oxidation on B/Cu codoped graphene is 0.536 eV by the Eley-Rideal mechanism. Further analysis shows that the spin selection rule can provide well theoretical insight into high activity of our suggested SAC. The concept of n-p codoping may lead to new strategy in large-scale synthesis of stable single-atom catalysts.

Shifts in leaf N:P stoichiometry during rehabilitation in highly alkaline bauxite processing residue sand

PubMed Central

Goloran, Johnvie B.; Chen, Chengrong; Phillips, Ian R.; Elser, James J.

2015-01-01

Large quantities of sodic and alkaline bauxite residue are produced globally as a by-product from alumina refineries. Ecological stoichiometry of key elements [nitrogen (N) and phosphorus (P)] plays a critical role in establishing vegetation cover in bauxite residue sand (BRS). Here we examined how changes in soil chemical properties over time in rehabilitated sodic and alkaline BRS affected leaf N to P stoichiometry of native species used for rehabilitation. Both Ca and soil pH influenced the shifts in leaf N:P ratios of the study species as supported by consistently significant positive relationships (P < 0.001) between these soil indices and leaf N:P ratios. Shifts from N to P limitation were evident for N-fixing species, while N limitation was consistently experienced by non-N-fixing plant species. In older rehabilitated BRS embankments, soil and plant indices (Ca, Na, pH, EC, ESP and leaf N:P ratios) tended to align with those of the natural ecosystem, suggesting improved rehabilitation performance. These findings highlight that leaf N:P stoichiometry can effectively provide a meaningful assessment on understanding nutrient limitation and productivity of native species used for vegetating highly sodic and alkaline BRS, and is a crucial indicator for assessing ecological rehabilitation performance. PMID:26443331

Shifts in leaf N:P stoichiometry during rehabilitation in highly alkaline bauxite processing residue sand.

PubMed

Goloran, Johnvie B; Chen, Chengrong; Phillips, Ian R; Elser, James J

2015-10-07

Large quantities of sodic and alkaline bauxite residue are produced globally as a by-product from alumina refineries. Ecological stoichiometry of key elements [nitrogen (N) and phosphorus (P)] plays a critical role in establishing vegetation cover in bauxite residue sand (BRS). Here we examined how changes in soil chemical properties over time in rehabilitated sodic and alkaline BRS affected leaf N to P stoichiometry of native species used for rehabilitation. Both Ca and soil pH influenced the shifts in leaf N:P ratios of the study species as supported by consistently significant positive relationships (P < 0.001) between these soil indices and leaf N:P ratios. Shifts from N to P limitation were evident for N-fixing species, while N limitation was consistently experienced by non-N-fixing plant species. In older rehabilitated BRS embankments, soil and plant indices (Ca, Na, pH, EC, ESP and leaf N:P ratios) tended to align with those of the natural ecosystem, suggesting improved rehabilitation performance. These findings highlight that leaf N:P stoichiometry can effectively provide a meaningful assessment on understanding nutrient limitation and productivity of native species used for vegetating highly sodic and alkaline BRS, and is a crucial indicator for assessing ecological rehabilitation performance.

N:P ratios, light limitation, and cyanobacterial dominance in a subtropical lake impacted by non-point source nutrient pollution.

PubMed

Havens, Karl E; James, R Thomas; East, Therese L; Smith, Val H

2003-01-01

A long-term (28-year) data set was used to investigate historical changes in concentrations of phosphorus (P), nitrogen (N), N:P ratios, and Secchi disk transparency in a shallow subtropical lake (Lake Okeechobee, Florida, USA). The aim was to evaluate changes in the risk of N2-fixing cyanobacterial blooms, which have infrequently occurred in the lake's pelagic zone. Predictions regarding bloom risk were based on previously published N:P ratio models. Temporal trends in the biomass of cyanobacteria were evaluated using phytoplankton data collected in 1974, 1989-1992, and 1997-2000. Concentrations of pelagic total P increased from near 50 microg l-1 in the mid-1970s to over 100 microg l-1 in the late 1990s. Coincidentally, the total N:P (mass) ratio decreased from 30:1 to below 15:1, and soluble N:P ratio decreased from 15:1 to near 6:1, in the lake water. Published empirical models predict that current conditions favor cyanobacteria. The observations confirm this prediction: cyanobacteria presently account for 50-80% of total phytoplankton biovolume. The historical decrease in TN:TP ratio in the lake can be attributed to a decreased TN:TP ratio in the inflow water and to a decline in the lake's assimilation of P, relative to N. Coincident with these declines in total and soluble N:P ratios, Secchi disk transparency declined from 0.6 m to near 0.3 m, possibly due to increased mineral turbidity in the lake water. Empirical models predict that under the turbid, low irradiance conditions that prevail in this lake, non-heterocystous cyanobacteria should dominate the phytoplankton. Our observations confirmed this prediction: non-N2-fixing taxa (primarily Oscillatoria and Lyngbya spp.) typically dominated the cyanobacteria community during the last decade. The only exception was a year with very low water levels, when heterocystous N2-fixing Anabaena became dominant. In the near-shore regions of this shallow lake, low N:P ratios potentially favor blooms of N2-fixing

The mechanism by which a propeptide-encoded pH sensor regulates spatiotemporal activation of furin.

PubMed

Williamson, Danielle M; Elferich, Johannes; Ramakrishnan, Parvathy; Thomas, Gary; Shinde, Ujwal

2013-06-28

The proprotein convertase furin requires the pH gradient of the secretory pathway to regulate its multistep, compartment-specific autocatalytic activation. Although His-69 within the furin prodomain serves as the pH sensor that detects transport of the propeptide-enzyme complex to the trans-Golgi network, where it promotes cleavage and release of the inhibitory propeptide, a mechanistic understanding of how His-69 protonation mediates furin activation remains unclear. Here we employ biophysical, biochemical, and computational approaches to elucidate the mechanism underlying the pH-dependent activation of furin. Structural analyses and binding experiments comparing the wild-type furin propeptide with a nonprotonatable His-69 → Leu mutant that blocks furin activation in vivo revealed protonation of His-69 reduces both the thermodynamic stability of the propeptide as well as its affinity for furin at pH 6.0. Structural modeling combined with mathematical modeling and molecular dynamic simulations suggested that His-69 does not directly contribute to the propeptide-enzyme interface but, rather, triggers movement of a loop region in the propeptide that modulates access to the cleavage site and, thus, allows for the tight pH regulation of furin activation. Our work establishes a mechanism by which His-69 functions as a pH sensor that regulates compartment-specific furin activation and provides insights into how other convertases and proteases may regulate their precise spatiotemporal activation.

The Mechanism by Which a Propeptide-encoded pH Sensor Regulates Spatiotemporal Activation of Furin*

PubMed Central

Williamson, Danielle M.; Elferich, Johannes; Ramakrishnan, Parvathy; Thomas, Gary; Shinde, Ujwal

2013-01-01

The proprotein convertase furin requires the pH gradient of the secretory pathway to regulate its multistep, compartment-specific autocatalytic activation. Although His-69 within the furin prodomain serves as the pH sensor that detects transport of the propeptide-enzyme complex to the trans-Golgi network, where it promotes cleavage and release of the inhibitory propeptide, a mechanistic understanding of how His-69 protonation mediates furin activation remains unclear. Here we employ biophysical, biochemical, and computational approaches to elucidate the mechanism underlying the pH-dependent activation of furin. Structural analyses and binding experiments comparing the wild-type furin propeptide with a nonprotonatable His-69 → Leu mutant that blocks furin activation in vivo revealed protonation of His-69 reduces both the thermodynamic stability of the propeptide as well as its affinity for furin at pH 6.0. Structural modeling combined with mathematical modeling and molecular dynamic simulations suggested that His-69 does not directly contribute to the propeptide-enzyme interface but, rather, triggers movement of a loop region in the propeptide that modulates access to the cleavage site and, thus, allows for the tight pH regulation of furin activation. Our work establishes a mechanism by which His-69 functions as a pH sensor that regulates compartment-specific furin activation and provides insights into how other convertases and proteases may regulate their precise spatiotemporal activation. PMID:23653353

Effect of NH4-N/P and Ca/P molar ratios on the reactive crystallization of calcium phosphates for phosphorus recovery from wastewater

NASA Astrophysics Data System (ADS)

Vasenko, Liubov; Qu, Haiyan

2017-02-01

In this work, the effects of operational parameters, initial phosphorus concentration and molar ratios of Ca/P and NH4-N/P (further in the text N/P), on the nature and purity of precipitated phosphorus products have been investigated in an artificial system that mimics the supernatant in wastewater treatment plants. Metastable zone width was determined for two target phosphorus products: DCPD (dicalcium phosphate dihydrate) and HAp (hydroxyapatite) in the range of pH 4.5 - 7. HAp crystallizes at final pH higher than 6.3 while DCPD crystallizes at the final pH in between 4.7 and 5.7. At the final pH 5.7 - 6.3 and at pH lower than 4.7 the mixtures of DCPD and HAp were obtained. It was observed that N/P ratio affects not only the metastable zone width but also the kinetics of crystal growth for both DCPD and HAp: the higher the N/P ratio, the lower is the growth rate for both P-products. Investigation of the effect of Ca/P and N/P ratios on the nucleation and crystal growth of DCPD in batch crystallization experiment was performed. It showed that at high supersaturation level, crystals with larger median size can be obtained at higher N/P ratio despite the negative effects of N/P ratio on the growth rate of the crystals.

Low energy scattering cross section ratios of 14N(p ,p ) 14N

NASA Astrophysics Data System (ADS)

deBoer, R. J.; Bardayan, D. W.; Görres, J.; LeBlanc, P. J.; Manukyan, K. V.; Moran, M. T.; Smith, K.; Tan, W.; Uberseder, E.; Wiescher, M.; Bertone, P. F.; Champagne, A. E.; Islam, M. S.

2015-04-01

Background: The slowest reaction in the first CNO cycle is 14N(p ,γ ) 15O , therefore its rate determines the overall energy production efficiency of the entire cycle. The cross section presents several strong resonance contributions, especially for the ground-state transition. Some of the properties of the corresponding levels in the 15O compound nucleus remain uncertain, which affects the uncertainty in extrapolating the capture cross section to the low energy range of astrophysical interest. Purpose: The 14N(p ,γ ) 15O cross section can be described by using the phenomenological R matrix. Over the energy range of interest, only the proton and γ -ray channels are open. Since resonance capture makes significant contributions to the 14N(p ,γ ) 15O cross section, resonant proton scattering data can be used to provide additional constraints on the R -matrix fit of the capture data. Methods: A 4 MV KN Van de Graaff accelerator was used to bombard protons onto a windowless gas target containing enriched 14N gas over the proton energy range from Ep=1.0 to 3.0 MeV. Scattered protons were detected at θlab=90 , 120∘, 135∘, 150∘, and 160∘ using ruggedized silicon detectors. In addition, a 10 MV FN Tandem Van de Graaff accelerator was used to accelerate protons onto a solid Adenine (C5H5N5 ) target, of natural isotopic abundance, evaporated onto a thin self-supporting carbon backing, over the energy range from Ep=1.8 to 4.0 MeV. Scattered protons were detected at 28 angles between θlab=30 .4∘ and 167 .7∘ by using silicon photodiode detectors. Results: Relative cross sections were extracted from both measurements. While the relative cross sections do not provide as much constraint as absolute measurements, they greatly reduce the dependence of the data on otherwise significant systematic uncertainties, which are more difficult to quantify. The data are fit simultaneously using an R -matrix analysis and level energies and proton widths are extracted. Even

Conformational Stability of the NH2-Terminal Propeptide of the Precursor of Pulmonary Surfactant Protein SP-B

PubMed Central

Bañares-Hidalgo, Ángeles; Estrada, Pilar

2016-01-01

Assembly of pulmonary surfactant lipid-protein complexes depends on conformational changes coupled with proteolytic maturation of proSP-B, the precursor of pulmonary surfactant protein B (SP-B), along the surfactant biogenesis pathway in pneumocytes. Conformational destabilization of the N-terminal propeptide of proSP-B (SP-BN) triggers exposure of the mature SP-B domain for insertion into surfactant lipids. We have studied the conformational stability during GdmCl- or urea-promoted unfolding of SP-BN with trp fluorescence and circular dichroism spectroscopies. Binding of the intermediate states to bis-ANS suggests their molten globule-like character. ΔG0H2O was ~ 12.7 kJ·mol-1 either with urea or GdmCl. None of the thermal transitions of SP-BN detected by CD correspond to protein unfolding. Differential scanning calorimetry of SP-BN evidenced two endothermic peaks involved in oligomer dissociation as confirmed with 2 M urea. Ionic strength was relevant since at 150 mM NaCl, the process originating the endotherm at the highest temperature was irreversible (Tm2 = 108.5°C) with an activation energy of 703.8 kJ·mol-1. At 500 mM NaCl the process became reversible (Tm2 = 114.4°C) and data were fitted to the Non-two States model with two subpeaks. No free thiols in the propeptide could be titrated by DTNB with or without 5.7 M GdmCl, indicating disulfide bonds establishment. PMID:27380171

Diffusion lengths in irradiated N/P InP-on-Si solar cells

NASA Technical Reports Server (NTRS)

Wojtczuk, Steven; Colerico, Claudia; Summers, Geoffrey P.; Walters, Robert J.; Burke, Edward A.

1995-01-01

Indium phosphide (InP) solar cells are being made on silicon (Si) wafers (InP/Si) to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers compared to InP or germanium (Ge) wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. InP/Si cells have higher absolute efficiency after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells. In this work, base electron diffusion lengths in the N/P cell are extracted from measured AM0 short-circuit photocurrent at various irradiation levels out to an equivalent 1 MeV fluence of 1017 1 MeV electrons/sq cm for a 1 sq cm 12% BOL InP/Si cell. These values are then checked for consistency by comparing measured Voc data with a theoretical Voc model that includes a dark current term that depends on the extracted diffusion lengths.

N/P GaAs concentrator solar cells with an improved grid and bushbar contact design

NASA Technical Reports Server (NTRS)

Desalvo, G. C.; Mueller, E. H.; Barnett, A. M.

1985-01-01

The major requirements for a solar cell used in space applications are high efficiency at AMO irradiance and resistance to high energy radiation. Gallium arsenide, with a band gap of 1.43 eV, is one of the most efficient sunlight to electricity converters (25%) when the the simple diode model is used to calculate efficiencies at AMO irradiance, GaAs solar cells are more radiation resistant than silicon solar cells and the N/P GaAs device has been reported to be more radiation resistant than similar P/N solar cells. This higher resistance is probably due to the fact that only 37% of the current is generated in the top N layer of the N/P cell compared to 69% in the top layer of a P/N solar cell. This top layer of the cell is most affected by radiation. It has also been theoretically calculated that the optimized N/P device will prove to have a higher efficiency than a similar P/N device. The use of a GaP window layer on a GaAs solar cell will avoid many of the inherent problems normally associated with a GaAlAs window while still proving good passivation of the GaAs surface. An optimized circular grid design for solar cell concentrators has been shown which incorporates a multi-layer metallization scheme. This multi-layer design allows for a greater current carrying capacity for a unit area of shading, which results in a better output efficiency.

Conformational changes of the N-terminal part of Mason-Pfizer monkey virus p12 protein during multimerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knejzlik, Zdenek; Ulbrich, Pavel; Strohalm, Martin

2009-10-10

The Mason-Pfizer monkey virus is a prototype Betaretrovirus with the defining characteristic that it assembles spherical immature particles from Gag-related polyprotein precursors within the cytoplasm of the infected cell. It was shown previously that the N-terminal part of the Gag p12 domain (wt-Np12) is required for efficient assembly. However, the precise role for p12 in mediating Gag-Gag interaction is still poorly understood. In this study we employed detailed circular dichroism spectroscopy, electron microscopy and ultracentrifugation analyses of recombinant wt-Np12 prepared by in vitro transcription and translation. The wt-Np12 domain fragment forms fibrillar structures in a concentration-dependent manner. Assembly into fibersmore » is linked to a conformational transition from unfolded or another non-periodical state to alpha-helix during multimerization.« less

A novel subtilase inhibitor in plants shows structural and functional similarities to protease propeptides.

PubMed

Hohl, Mathias; Stintzi, Annick; Schaller, Andreas

2017-04-14

The propeptides of subtilisin-like serine proteinases (subtilases, SBTs) serve dual functions as intramolecular chaperones that are required for enzyme folding and as inhibitors of the mature proteases. SBT propeptides are homologous to the I9 family of protease inhibitors that have only been described in fungi. Here we report the identification and characterization of subtilisin propeptide-like inhibitor 1 (SPI-1) from Arabidopsis thaliana Sequence similarity and the shared β-α-β-β-α-β core structure identified SPI-1 as a member of the I9 inhibitor family and as the first independent I9 inhibitor in higher eukaryotes. SPI-1 was characterized as a high-affinity, tight-binding inhibitor of Arabidopsis subtilase SBT4.13 with K d and K i values in the picomolar range. SPI-1 acted as a stable inhibitor of SBT4.13 over the physiologically relevant range of pH, and its inhibitory profile included many other SBTs from plants but not bovine chymotrypsin or bacterial subtilisin A. Upon binding to SBT4.13, the C-terminal extension of SPI-1 was proteolytically cleaved. The last four amino acids at the newly formed C terminus of SPI-1 matched both the cleavage specificity of SBT4.13 and the consensus sequence of Arabidopsis SBTs at the junction of the propeptide with the catalytic domain. The data suggest that the C terminus of SPI-1 acts as a competitive inhibitor of target proteases as it remains bound to the active site in a product-like manner. SPI-1 thus resembles SBT propeptides with respect to its mode of protease inhibition. However, in contrast to SBT propeptides, SPI-1 could not substitute as a folding assistant for SBT4.13. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Statistical Model Analysis of (n,p) Cross Sections and Average Energy For Fission Neutron Spectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Odsuren, M.; Khuukhenkhuu, G.

2011-06-28

Investigation of charged particle emission reaction cross sections for fast neutrons is important to both nuclear reactor technology and the understanding of nuclear reaction mechanisms. In particular, the study of (n,p) cross sections is necessary to estimate radiation damage due to hydrogen production, nuclear heating and transmutations in the structural materials of fission and fusion reactors. On the other hand, it is often necessary in practice to evaluate the neutron cross sections of the nuclides for which no experimental data are available.Because of this, we carried out the systematical analysis of known experimental (n,p) and (n,a) cross sections for fastmore » neutrons and observed a systematical regularity in the wide energy interval of 6-20 MeV and for broad mass range of target nuclei. To explain this effect using the compound, pre-equilibrium and direct reaction mechanisms some formulae were deduced. In this paper, in the framework of the statistical model known experimental (n,p) cross sections averaged over the thermal fission neutron spectrum of U-235 are analyzed. It was shown that the experimental data are satisfactorily described by the statistical model. Also, in the case of (n,p) cross sections the effective average neutron energy for fission spectrum of U-235 was found to be around 3 MeV.« less

Characterization of an extensin-modifying metalloprotease: N-terminal processing and substrate cleavage pattern of Pectobacterium carotovorum Prt1.

PubMed

Feng, Tao; Nyffenegger, Christian; Højrup, Peter; Vidal-Melgosa, Silvia; Yan, Kok-Phen; Fangel, Jonatan Ulrik; Meyer, Anne S; Kirpekar, Finn; Willats, William G; Mikkelsen, Jørn D

2014-12-01

Compared to other plant cell wall-degrading enzymes, proteases are less well understood. In this study, the extracellular metalloprotease Prt1 from Pectobacterium carotovorum (formerly Erwinia carotovora) was expressed in Escherichia coli and characterized with respect to N-terminal processing, thermal stability, substrate targets, and cleavage patterns. Prt1 is an autoprocessing protease with an N-terminal signal pre-peptide and a pro-peptide which has to be removed in order to activate the protease. The sequential cleavage of the N-terminus was confirmed by mass spectrometry (MS) fingerprinting and N-terminus analysis. The optimal reaction conditions for the activity of Prt1 on azocasein were at pH 6.0, 50 °C. At these reaction conditions, K M was 1.81 mg/mL and k cat was 1.82 × 10(7) U M(-1). The enzyme was relatively stable at 50 °C with a half-life of 20 min. Ethylenediaminetetraacetic acid (EDTA) treatment abolished activity; Zn(2+) addition caused regain of the activity, but Zn(2+)addition decreased the thermal stability of the Prt1 enzyme presumably as a result of increased proteolytic autolysis. In addition to casein, the enzyme catalyzed degradation of collagen, potato lectin, and plant extensin. Analysis of the cleavage pattern of different substrates after treatment with Prt1 indicated that the protease had a substrate cleavage preference for proline in substrate residue position P1 followed by a hydrophobic residue in residue position P1' at the cleavage point. The activity of Prt1 against plant cell wall structural proteins suggests that this enzyme might become an important new addition to the toolbox of cell-wall-degrading enzymes for biomass processing.

Two-terminal monolithic InP-based tandem solar cells with tunneling intercell ohmic connections

NASA Technical Reports Server (NTRS)

Shen, C. C.; Chang, P. T.; Emery, K. A.

1991-01-01

A monolithic two-terminal InP/InGaAsP tandem solar cell was successfully fabricated. This tandem solar cell consists of a p/n InP homojunction top subcell and a 0.95 eV p/n InGaAsP homojunction bottom subcell. A patterned 0.95 eV n(+)/p(+) InGaAsP tunnel diode was employed as an intercell ohmic connection. The solar cell structure was prepared by two-step liquid phase epitaxial growth. Under one sun, AM1.5 global illumination, the best tandem cell delivered a conversion efficiency of 14.8 pct.

A method for (n,alpha) and (n,p) cross section measurements using a lead slowing-down spectrometer

NASA Astrophysics Data System (ADS)

Thompson, Jason Tyler

The need for nuclear data comes from several sources including astrophysics, stockpile stewardship, and reactor design. Photodisintegration, neutron capture, and charged particle out reactions on stable or short-lived radioisotopes play crucial roles during stellar evolution and forming solar isotopic abundances whereas these reactions can affect the safety of our national weapons stockpile or criticality and safety calculations for reactors. Although models can be used to predict some of these values, these predictions are only as good as the experimental data that constrains them. For neutron-induced emission of α particles and protons ((n,α) and (n,p) reactions) at energies below 1 MeV, the experimental data is at best scarce and models must rely on extrapolations from unlike situations, (i.e. different reactions, isotopes, and energies) providing ample room for uncertainty. In this work a new method of measuring energy dependent (n,α) and (n,p) cross sections was developed for the energy range of 0.1 eV - ˜100 keV using a lead slowing-down spectrometer (LSDS). The LSDS provides a ˜10 4 neutron flux increase over the more conventionally used time-of-flight (ToF) methods at equivalent beam conditions, allowing for the measurement of small cross sections (µb’s to mb’s) while using small sample masses (µg’s to mg’s). Several detector concepts were designed and tested, including specially constructed Canberra passivated, implanted, planar silicon (PIPS) detectors; and gas-electron-multiplier (GEM) foils. All designs are compensated to minimize γ-flash problems. The GEM detector was found to function satisfactory for (n,α) measurements, but the PIPS detectors were found to be better suited for (n,p) reaction measurements. A digital data acquisition (DAQ) system was programmed such that background can be measured simultaneously with the reaction cross section. Measurements of the 147Sm(n,α)144Nd and 149 Sm(n,α)146Nd reaction cross sections were

Application experiments to trace N-P interactions in forest ecosystems

NASA Astrophysics Data System (ADS)

Krüger, Jaane; Niederberger, Jörg; Schulz, Stefanie; Lang, Friederike

2017-04-01

Phosphorus is a limited resource and there is increasing debate regarding the principles of tight P recycling. Forest ecosystems show commonly high P use efficiencies but the processes behind this phenomenon are still unresolved. In frame of the priority program "SPP 1685 Ecosystem nutrition - Forest strategies for limited phosphorus resources" around 70 researchers from different disciplines collaborate to unravel these processes. The overall hypothesis to be tested is that the P nutrition strategy of forest ecosystems at sites rich in mineral P is characterized by high P uptake efficiency (acquiring systems). In contrast, the P strategy of forest ecosystems facing low soil P stocks is characterized by highly efficient mechanisms of P recycling. To test this hypothesis, we analyzed five beech forest ecosystems on silicate rock with different parent materials representing a gradient of total P stocks (160 - 900 g P m-2, down to 1m soil depth). In fact, we found evidence confirming our hypothesis, but controls and drivers of P strategies are still unknown as other environmental variables differ. One of those might be the N content, as organisms strive to reach a specific internal N:P ratio. Thus, an additional application of N might also alter P nutrition. To test this, we established a factorial P x N application experiment at three of the study sites. With our presentation we will introduce this experiment and give a review on published P x N experiments discussing different advantages and disadvantages of different basic conditions (e.g. amount and application form, doses, sampling and statistical design, monitoring periods, budget calculation, isotopic tracing). Finally, we want to initiate a common discussion on the standardization of P x N field experiments to enable interdisciplinary and across-compartment comparisons (e.g. different land use, different climate zones, terrestrial and aquatic ecosystems).

Interaction study of rice stripe virus proteins reveals a region of the nucleocapsid protein (NP) required for NP self-interaction and nuclear localization.

PubMed

Lian, Sen; Cho, Won Kyong; Jo, Yeonhwa; Kim, Sang-Min; Kim, Kook-Hyung

2014-04-01

Rice stripe virus (RSV), which belongs to the genus Tenuivirus, is an emergent virus problem. The RSV genome is composed of four single-strand RNAs (RNA1-RNA4) and encodes seven proteins. We investigated interactions between six of the RSV proteins by yeast-two hybrid (Y2H) assay in vitro and by bimolecular fluorescence complementation (BiFC) in planta. Y2H identified self-interaction of the nucleocapsid protein (NP) and NS3, while BiFC revealed self-interaction of NP, NS3, and NCP. To identify regions(s) and/or crucial amino acid (aa) residues required for NP self-interaction, we generated various truncated and aa substitution mutants. Y2H assay showed that the N-terminal region of NP (aa 1-56) is necessary for NP self-interaction. Further analysis with substitution mutants demonstrated that additional aa residues located at 42-47 affected their interaction with full-length NP. These results indicate that the N-terminal region (aa 1-36 and 42-47) is required for NP self-interaction. BiFC and co-localization studies showed that the region required for NP self-interaction is also required for NP localization at the nucleus. Overall, our results indicate that the N-terminal region (aa 1-47) of the NP is important for NP self-interaction and that six aa residues (42-47) are essential for both NP self-interaction and nuclear localization. Copyright © 2014 Elsevier B.V. All rights reserved.

Results of a real-time irradiation of lithium P/N and conventional N/P silicon solar cells.

NASA Technical Reports Server (NTRS)

Reynard, D. L.; Peterson, D. G.

1972-01-01

Eight types of lithium-diffused P/N and three types of conventional 10 ohm-cm N/P silicon solar cells were irradiated at four different temperatures with a strontium-90 radioisotope at a rate typical of that expected in earth orbit. The six-month irradiation confirmed earlier accelerator results, showed that certain cell types outperform others at the various temperatures, and, in general, verified the recent improvements and potential usefulness of lithium solar cells. The experimental approach and statistical methods and analyses employed yielded increased confidence in the validity of the results. Injection level effects were observed to be significant.

[At the origin of the development of russian angiology (dedicated to the 150 birthday of academician N.P. Kravkov)].

PubMed

Uzbekova, D G

2015-01-01

The article describes scientific activity of outstanding pharmacologist, Academician N.P. Kravkov (1865-1924) on studying dynamics of the vascular system in experiment: Using the method of isolated animal organs of animals, N.P. Kravkov discovered self-maintained periodic contractions of vessels independent of the central nervous system and not associated with cardiac contractions. On isolated animal organs (heart, kidneys, spleen, womb, pancreas and others) specialists of the laboratory of N.P. Kravkov studied vascular reactions and sensitivity of vascular zones to administration of pharmacological agents in normal conditions and on various experimental ''pathological" models. For studying physiology and pharmacology of coronary vessels irrespective of cardiac contractions masking change in their lumen N.P. Kravkov suggested his original method of cardiac arrest by means of administration of strophanthin followed by passing through vessels of the unfunctioning heart solutions of various pharmacological substances. N.P. Kravkov and !{is followers studied alterations in vascular tonicity on isolated organs of cadavers of people who had died of various diseases: tuberculosis, typhoid fever and epidemic typhus, scarlet fever, measles, diphtheria, pneumonia et cet. The scientist believed that studying the functional state of vessels on post-mortem material would make it possible to more precisely and accurately solve the problem of intravital alterations thereof N.P. Kravkov's works on physiology and pathology of'the vascular system served as the basis for the developing clinical discipline, i.e. angiology.

Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

PubMed

Liu, Junzhuo; Vyverman, Wim

2015-03-01

The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dimerization of nitrophorin 4 at low pH and comparison to the K1A mutant of nitrophorin 1.

PubMed

Berry, Robert E; Yang, Fei; Shokhireva, Tatiana K; Amoia, Angela M; Garrett, Sarah A; Goren, Allena M; Korte, Stephanie R; Zhang, Hongjun; Weichsel, Andrzej; Montfort, William R; Walker, F Ann

2015-01-20

Nitrophorin 4, one of the four NO-carrying heme proteins from the salivary glands of Rhodnius prolixus, forms a homodimer at pH 5.0 with a Kd of ∼8 μM. This dimer begins to dissociate at pH 5.5 and is completely dissociated to monomer at pH 7.3, even at 3.7 mM. The dimer is significantly stabilized by binding NO to the heme and at pH 7.3 would require dilution to well below 0.2 mM to completely dissociate the NP4-NO homodimer. The primary techniques used for investigating the homodimer and the monomer-dimer equilibrium were size-exclusion fast protein liquid chromatography at pH 5.0 and (1)H{(15)N} heteronuclear single-quantum coherence spectroscopy as a function of pH and concentration. Preparation of site-directed mutants of NP4 (A1K, D30A, D30N, V36A/D129A/L130A, K38A, R39A, K125A, K125E, D132A, L133V, and K38Q/R39Q/K125Q) showed that the N-terminus, D30, D129, D132, at least one heme propionate, and, by association, likely also E32 and D35 are involved in the dimerization. The "closed loop" form of the A-B and G-H flexible loops of monomeric NP4, which predominates in crystal structures of the monomeric protein reported at pH 5.6 but not at pH 7.5 and which involves all of the residues listed above except D132, is required for dimer formation. Wild-type NP1 does not form a homodimer, but NP1(K1A) and native N-terminal NP1 form dimers in the presence of NO. The homodimer of NP1, however, is considerably less stable than that of NP4 in the absence of NO. This suggests that additional aspartate or glutamate residues present in the C-terminal region of NP4, but not NP1, are also involved in stabilizing the dimer.

Dimerization of Nitrophorin 4 at Low pH and Comparison to the K1A Mutant of Nitrophorin 1

PubMed Central

2015-01-01

Nitrophorin 4, one of the four NO-carrying heme proteins from the salivary glands of Rhodnius prolixus, forms a homodimer at pH 5.0 with a Kd of ∼8 μM. This dimer begins to dissociate at pH 5.5 and is completely dissociated to monomer at pH 7.3, even at 3.7 mM. The dimer is significantly stabilized by binding NO to the heme and at pH 7.3 would require dilution to well below 0.2 mM to completely dissociate the NP4-NO homodimer. The primary techniques used for investigating the homodimer and the monomer–dimer equilibrium were size-exclusion fast protein liquid chromatography at pH 5.0 and 1H{15N} heteronuclear single-quantum coherence spectroscopy as a function of pH and concentration. Preparation of site-directed mutants of NP4 (A1K, D30A, D30N, V36A/D129A/L130A, K38A, R39A, K125A, K125E, D132A, L133V, and K38Q/R39Q/K125Q) showed that the N-terminus, D30, D129, D132, at least one heme propionate, and, by association, likely also E32 and D35 are involved in the dimerization. The “closed loop” form of the A–B and G–H flexible loops of monomeric NP4, which predominates in crystal structures of the monomeric protein reported at pH 5.6 but not at pH 7.5 and which involves all of the residues listed above except D132, is required for dimer formation. Wild-type NP1 does not form a homodimer, but NP1(K1A) and native N-terminal NP1 form dimers in the presence of NO. The homodimer of NP1, however, is considerably less stable than that of NP4 in the absence of NO. This suggests that additional aspartate or glutamate residues present in the C-terminal region of NP4, but not NP1, are also involved in stabilizing the dimer. PMID:25489673

Dimerization of Nitrophorin 4 at Low pH and Comparison to the K1A Mutant of Nitrophorin 1

DOE PAGES

Berry, Robert E.; Yang, Fei; Shokhireva, Tatiana K.; ...

2014-12-09

Nitrophorin 4, one of the four NO-carrying heme proteins from the salivary glands of Rhodnius prolixus, forms a homodimer at pH 5.0 with a K d of ~8 μM. This dimer begins to dissociate at pH 5.5 and is completely dissociated to monomer at pH 7.3, even at 3.7 mM. The dimer is significantly stabilized by binding NO to the heme and at pH 7.3 would require dilution to well below 0.2 mM to completely dissociate the NP4-NO homodimer. The primary techniques used for investigating the homodimer and the monomer–dimer equilibrium were size-exclusion fast protein liquid chromatography at pH 5.0more » and 1H{ 15N} heteronuclear single-quantum coherence spectroscopy as a function of pH and concentration. Preparation of site-directed mutants of NP4 (A1K, D30A, D30N, V36A/D129A/L130A, K38A, R39A, K125A, K125E, D132A, L133V, and K38Q/R39Q/K125Q) showed that the N-terminus, D30, D129, D132, at least one heme propionate, and, by association, likely also E32 and D35 are involved in the dimerization. The “closed loop” form of the A–B and G–H flexible loops of monomeric NP4, which predominates in crystal structures of the monomeric protein reported at pH 5.6 but not at pH 7.5 and which involves all of the residues listed above except D132, is required for dimer formation. Wild-type NP1 does not form a homodimer, but NP1(K1A) and native N-terminal NP1 form dimers in the presence of NO. Lastly, the homodimer of NP1, however, is considerably less stable than that of NP4 in the absence of NO. This suggests that additional aspartate or glutamate residues present in the C-terminal region of NP4, but not NP1, are also involved in stabilizing the dimer.« less

Acousto-defect interaction in irradiated and non-irradiated silicon n+-p structures

NASA Astrophysics Data System (ADS)

Olikh, O. Ya.; Gorb, A. M.; Chupryna, R. G.; Pristay-Fenenkov, O. V.

2018-04-01

The influence of ultrasound on current-voltage characteristics of non-irradiated silicon n+-p structures as well as silicon structures exposed to reactor neutrons or 60Co gamma radiation has been investigated experimentally. It has been found that the ultrasound loading of the n+-p structure leads to the reversible change of shunt resistance, carrier lifetime, and ideality factor. Specifically, considerable acoustically induced alteration of the ideality factor and the space charge region lifetime was observed in the irradiated samples. The experimental results were described by using the models of coupled defect level recombination, Shockley-Read-Hall recombination, and dislocation-induced impedance. The experimentally observed phenomena are associated with the increase in the distance between coupled defects as well as the extension of the carrier capture coefficient of complex point defects and dislocations. It has been shown that divacancies and vacancy-interstitial oxygen pairs are effectively modified by ultrasound in contrast to interstitial carbon-interstitial oxygen complexes.

Pub1p C-Terminal RRM Domain Interacts with Tif4631p through a Conserved Region Neighbouring the Pab1p Binding Site

PubMed Central

Rico-Lastres, Palma; Pérez-Cañadillas, José Manuel

2011-01-01

Pub1p, a highly abundant poly(A)+ mRNA binding protein in Saccharomyces cerevisiae, influences the stability and translational control of many cellular transcripts, particularly under some types of environmental stresses. We have studied the structure, RNA and protein recognition modes of different Pub1p constructs by NMR spectroscopy. The structure of the C-terminal RRM domain (RRM3) shows a non-canonical N-terminal helix that packs against the canonical RRM fold in an original fashion. This structural trait is conserved in Pub1p metazoan homologues, the TIA-1 family, defining a new class of RRM-type domains that we propose to name TRRM (TIA-1 C-terminal domain-like RRM). Pub1p TRRM and the N-terminal RRM1-RRM2 tandem bind RNA with high selectivity for U-rich sequences, with TRRM showing additional preference for UA-rich ones. RNA-mediated chemical shift changes map to β-sheet and protein loops in the three RRMs. Additionally, NMR titration and biochemical in vitro cross-linking experiments determined that Pub1p TRRM interacts specifically with the N-terminal region (1–402) of yeast eIF4G1 (Tif4631p), very likely through the conserved Box1, a short sequence motif neighbouring the Pab1p binding site in Tif4631p. The interaction involves conserved residues of Pub1p TRRM, which define a protein interface that mirrors the Pab1p-Tif4631p binding mode. Neither protein nor RNA recognition involves the novel N-terminal helix, whose functional role remains unclear. By integrating these new results with the current knowledge about Pub1p, we proposed different mechanisms of Pub1p recruitment to the mRNPs and Pub1p-mediated mRNA stabilization in which the Pub1p/Tif4631p interaction would play an important role. PMID:21931728

Activity of the C-terminal-dependent vacuolar sorting signal of horseradish peroxidase C1a is enhanced by its secondary structure.

PubMed

Matsui, Takeshi; Tabayashi, Ayako; Iwano, Megumi; Shinmyo, Atsuhiko; Kato, Ko; Nakayama, Hideki

2011-02-01

Plant class III peroxidase (PRX) catalyzes the oxidation and oxidative polymerization of a variety of phenolic compounds while reducing hydrogen peroxide. PRX proteins are classified into apoplast type and vacuole type based on the absence or the presence of C-terminal propeptides, which probably function as vacuolar sorting signals (VSSs). In this study, in order to improve our understanding of vacuole-type PRX, we analyzed regulatory mechanisms of vacuolar sorting of a model vacuole-type PRX, the C1a isozyme of horseradish (Armoracia rusticana) (HRP C1a). Using cultured transgenic tobacco cells and protoplasts derived from horseradish leaves, we characterized HRP C1a's VSS, which is a 15 amino acid C-terminal propeptide (C15). We found that the C-terminal hexapeptide of C15 (C6), which is well conserved among vacuole-type PRX proteins, forms the core of the C-terminal-dependent VSS. We also found that the function of C6 is enhanced by the remaining N-terminal part of C15 which probably folds into an amphiphilic α-helix.

Radiation damage in lithium-counterdoped N/P silicon solar cells

NASA Technical Reports Server (NTRS)

Hermann, A. M.; Swartz, C. K.; Brandhorst, H. W., Jr.; Weinberg, I.

1980-01-01

The radiation resistance and low-temperature annealing properties of lithium-counterdoped n(+)-p silicon solar cells are investigated. Cells fabricated from float zone and Czochralski grown silicon were irradiated with 1 MeV electrons and their performance compared to that of 0.35 ohm-cm control cells. The float zone cells demonstrated superior radiation resistance compared to the control cells, while no improvement was noted for the Czochralski grown cells. Annealing kinetics were found to lie between first and second order for relatively short times, and the most likely annealing mechanism was found to be the diffusion of lithium to defects with the subsequent neutralization of defects by combination with lithium. Cells with zero lithium gradients exhibited the best radiation resistance.

Antibody and T cell responses induced in chickens immunized with avian influenza virus N1 and NP DNA vaccine with chicken IL-15 and IL-18.

PubMed

Lim, Kian-Lam; Jazayeri, Seyed Davoud; Yeap, Swee Keong; Mohamed Alitheen, Noorjahan Banu; Bejo, Mohd Hair; Ideris, Aini; Omar, Abdul Rahman

2013-12-01

We had examined the immunogenicity of a series of plasmid DNAs which include neuraminidase (NA) and nucleoprotein (NP) genes from avian influenza virus (AIV). The interleukin-15 (IL-15) and interleukin-18 (IL-18) as genetic adjuvants were used for immunization in combination with the N1 and NP AIV genes. In the first trial, 8 groups of chickens were established with 10 specific-pathogen-free (SPF) chickens per group while, in the second trial 7 SPF chickens per group were used. The overall N1 enzyme-linked immunosorbent assay (ELISA) titer in chickens immunized with the pDis/N1+pDis/IL-15 was higher compared to the chickens immunized with the pDis/N1 and this suggesting that chicken IL-15 could play a role in enhancing the humoral immune response. Besides that, the chickens that were immunized at 14-day-old (Trial 2) showed a higher N1 antibody titer compared to the chickens that were immunized at 1-day-old (Trial 1). Despite the delayed in NP antibody responses, the chickens co-administrated with IL-15 were able to induce earlier and higher antibody response compared to the pDis/NP and pDis/NP+pDis/IL-18 inoculated groups. The pDis/N1+pDis/IL-15 inoculated chickens also induced higher CD8+ T cells increase than the pDis/N1 group in both trials (P<0.05). The flow cytometry results from both trials demonstrated that the pDis/N1+pDis/IL-18 groups were able to induce CD4+ T cells higher than the pDis/N1 group (P<0.05). Meanwhile, pDis/N1+pDis/IL-18 group was able to induce CD8+ T cells higher than the pDis/N1 group (P<0.05) in Trial 2 only. In the present study, pDis/NP was not significant (P>0.05) in inducing CD4+ and CD8+ T cells when co-administered with the pDis/IL-18 in both trials in comparison to the pDis/NP. Our data suggest that the pDis/N1+pDis/IL-15 combination has the potential to be used as a DNA vaccine against AIV in chickens. Copyright © 2013 Elsevier Ltd. All rights reserved.

Structural Basis for Specificity of Propeptide-Enzyme Interaction in Barley C1A Cysteine Peptidases

PubMed Central

Cambra, Inés; Hernández, David; Diaz, Isabel; Martinez, Manuel

2012-01-01

C1A cysteine peptidases are synthesized as inactive proenzymes. Activation takes place by proteolysis cleaving off the inhibitory propeptide. The inhibitory capacity of propeptides from barley cathepsin L and B-like peptidases towards commercial and barley cathepsins has been characterized. Differences in selectivity have been found for propeptides from L-cathepsins against their cognate and non cognate enzymes. Besides, the propeptide from barley cathepsin B was not able to inhibit bovine cathepsin B. Modelling of their three-dimensional structures suggests that most propeptide inhibitory properties can be explained from the interaction between the propeptide and the mature cathepsin structures. Their potential use as biotechnological tools is discussed. PMID:22615948

NXT1, a Novel Influenza A NP Binding Protein, Promotes the Nuclear Export of NP via a CRM1-Dependent Pathway.

PubMed

Chutiwitoonchai, Nopporn; Aida, Yoko

2016-07-28

Influenza remains a serious worldwide public health problem. After infection, viral genomic RNA is replicated in the nucleus and packed into viral ribonucleoprotein, which will then be exported to the cytoplasm via a cellular chromosome region maintenance 1 (CRM1)-dependent pathway for further assembly and budding. However, the nuclear export mechanism of influenza virus remains controversial. Here, we identify cellular nuclear transport factor 2 (NTF2)-like export protein 1 (NXT1) as a novel binding partner of nucleoprotein (NP) that stimulates NP-mediated nuclear export via the CRM1-dependent pathway. NXT1-knockdown cells exhibit decreased viral replication kinetics and nuclear accumulated viral RNA and NP. By contrast, NXT1 overexpression promotes nuclear export of NP in a CRM1-dependent manner. Pull-down assays suggest the formation of an NXT1, NP, and CRM1 complex, and demonstrate that NXT1 binds to the C-terminal region of NP. These findings reveal a distinct mechanism for nuclear export of the influenza virus and identify the NXT1/NP interaction as a potential target for antiviral drug development.

Molecular cloning and anti-invasive activity of cathepsin L propeptide-like protein from Calotropis procera R. Br. against cancer cells.

PubMed

Kwon, Chang Woo; Yang, Hee; Yeo, SuBin; Park, Kyung-Min; Jeong, Ae Jin; Lee, Ki Won; Ye, Sang-Kyu; Chang, Pahn-Shick

2018-12-01

Cathepsin L of cancer cells has been shown to play an important role in degradation of extracellular matrix for metastasis. In order to reduce cell invasion, cathepsin L propeptide-like proteins which are classified as the I29 family in the MEROPS peptidase database were characterized from Calotropis procera R. Br., rich in cysteine protease. Of 19 candidates, the cloned and expressed recombinant SnuCalCp03-propeptide (rSnuCalCp03-propeptide) showed a low nanomolar K i value of 2.3 ± 0.2 nM against cathepsin L. A significant inhibition of tumor cell invasion was observed with H1975, HT29, MDA-BM-231, PANC1, and PC3 with a 76, 67, 67, 63, and 79% reduction, respectively, in invasion observed in the presence of 400 nM of the rSnuCalCp03-propeptide. In addition, thermal and pH study showed rSnuCalCp03-propeptide consisting of secondary structures was stable at a broad range of temperatures (30-70 °C) and pH (2-10, except for 5 which is close to the isoelectric point of 5.2).

Strong electroluminescence from direct band and defects in Ge n+/p shallow junctions at room temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Guangyang; Li, Cheng, E-mail: lich@xmu.edu.cn; Chen, Chaowen

2016-05-09

Strong room temperature electroluminescence with two emission peaks at around 0.786 eV and 0.747 eV from Ge n+/p shallow junctions was reported. The peak at around 0.786 eV comes from direct band luminescence (DBL) in n + Ge regions, while the peak fixing at 0.747 eV is resulted from defects induced by ion implantation. Heavy n-type doping in Ge renders realization of strong defect-related luminescence (DRL) feasible. The peak intensity ratio of DRL/DBL decreases with increase of injection current since more electrons are filled in Γ valley. Above all, the Ge n+/p shallow junction is fully compatible with the source and drain in Gemore » metal-oxide-semiconductor field effect transistors.« less

Amino-terminal residues of ΔNp63, mutated in ectodermal dysplasia, are required for its transcriptional activity.

PubMed

Lena, Anna Maria; Duca, Sara; Novelli, Flavia; Melino, Sonia; Annicchiarico-Petruzzelli, Margherita; Melino, Gerry; Candi, Eleonora

2015-11-13

p63, a member of the p53 family, is a crucial transcription factor for epithelial development and skin homeostasis. Heterozygous mutations in TP63 gene have been associated with human ectodermal dysplasia disorders. Most of these TP63 mutations are missense mutations causing amino acidic substitutions at p63 DNA binding or SAM domains that reduce or abolish the transcriptional activity of mutants p63. A significant number of mutants, however, resides in part of the p63 protein that apparently do not affect DNA binding and/or transcriptional activity, such as the N-terminal domain. Here, we characterize five p63 mutations at the 5' end of TP63 gene aiming to understand the pathogenesis of the diseases and to uncover the role of ΔNp63α N-terminus residues in determining its transactivation potential. Copyright © 2015 Elsevier Inc. All rights reserved.

The effects of lithium counterdoping on radiation damage and annealing in n(+)p silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Brandhorst, H. W., Jr.; Mehta, S.; Swartz, C. K.

1984-01-01

Boron-doped silicon n(+)p solar cells were counterdoped with lithium by ion implantation and the resultant n(+)p cells irradiated by 1 MeV electrons. Performance parameters were determined as a function of fluence and a deep level transient spectroscopy (DLTS) study was conducted. The lithium counterdoped cells exhibited significantly increased radiation resistance when compared to boron doped control cells. Isochronal annealing studies of cell performance indicate that significant annealing occurs at 100 C. Isochronal annealing of the deep level defects showed a correlation between a single defect at E sub v + 0.43 eV and the annealing behavior of short circuit current in the counterdoped cells. The annealing behavior was controlled by dissociation and recombination of this defect. The DLTS studies showed that counterdoping with lithium eliminated three deep level defects and resulted in three new defects. The increased radiation resistance of the counterdoped cells is due to the interaction of lithium with oxygen, single vacancies and divacancies. The lithium-oxygen interaction is the most effective in contributing to the increased radiation resistance.

Influences of seasons, N/P ratios and chemical compounds on phosphorus removal performance in algal pond combined with constructed wetlands.

PubMed

Zhimiao, Zhao; Xinshan, Song; Yanping, Xiao; Yufeng, Zhao; Zhijie, Gong; Fanda, Lin; Yi, Ding; Wei, Wang; Tianling, Qin

2016-12-15

Nitrogen (N) and phosphorous (P) are main contaminants and P removal was restrained by several factors: season, N/P, and chemical compounds (CCs) in water ecosystems. In this paper, two algal ponds combined with constructed wetlands were built to increase the removal performance. Different hydraulic retention time (HRT), different N/P and chemical compounds were chosen to investigate the influences of the above factors on the contaminant removal performance. The optimum phosphorus removal rate was 69.74% under the nitrogen removal of 92.85% in influent containing PO 4 3- after 3-day HRT in algal pond combined with constructed wetlands. The investigation results indicated that these factors improved the nutrient removal efficiencies. Seasonal influence on the removal performance can be avoided by choosing the optimal HRT length of 3days. The higher N/P at 60 can improve the phosphorus removal and the lower N/P at 15 showed the stronger synergistic effect between phosphorus and nitrogen removals. Compared with PO 3 - and P 2 O 7 4- in influent, PO 4 3- affected phosphorus removal more significantly. The better linear fitting between organic phosphorus removal and nitrogen removal in influent contained P 2 O 7 4- was found. Algae can absorb nutrients for growth, and oxygen release, microbial activity intensification and microbial carbon replenishment induced by algae will improve the performance. The study suggested that the control of HRTs, N/Ps, CCs, and algae might be an effective way to improve wastewater treatment performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Forward- and reverse-bias tunneling effects in n/+/p silicon solar cells

NASA Technical Reports Server (NTRS)

Garlick, G. F. J.; Kachare, A. H.

1980-01-01

Excess currents due to field-assisted tunneling in both forward and reverse bias directions have been observed in n(+)-p silicon solar cells. These currents arise from the effect of conducting paths produced in the depletion layer by n(+) diffusion and cell processing. Forward-bias data indicate a small potential barrier with height of 0.04 eV at the n(+) end of conducting paths. Under reverse bias, excess tunneling currents involve a potential barrier at the p end of the conducting paths, the longer paths being associated with smaller barrier heights and dominating at the lower temperatures. Low-reverse-bias data give energy levels of 0.11 eV for lower temperatures (253-293 K) and 0.35 eV for higher temperatures (293-380 K). A model is suggested to explain the results.

ANABOLIC BONE WINDOW WITH WEEKLY TERIPARATIDE THERAPY IN POSTMENOPAUSAL OSTEOPOROSIS: A PILOT STUDY.

PubMed

Gopalaswamy, Vinaya; Dhibar, Deba Prasad; Gupta, Vipin; Arya, Ashutosh Kumar; Khandelwal, Niranjan; Bhansali, Anil; Garg, Sudhir Kumar; Agarwal, Neelam; Rao, Sudhaker D; Bhadada, Sanjay Kumar

2017-06-01

Osteoporosis is a major public health problem that reduces bone strength and increases fracture risk. Teriparatide is an established and the only currently available anabolic therapy for the treatment of postmenopausal osteoporosis (PMO) with a recommended daily dose of 20 μg given subcutaneously. However, there are limited data regarding the long-term effect of once-weekly teriparatide therapy on bone mineral density (BMD), bone turnover markers (BTMs), and anabolic bone window. In this prospective observational study, 26 patients with PMO were treated with weekly teriparatide therapy (60 μg) for 2 years. BMD was measured at baseline, 12 months, and 24 months. The bone formation marker type 1 collagen C-terminal propeptide (P1NP) and the bone resorption marker C-terminal telopeptide of type 1 collagen (CTx) were measured at baseline; 6 weeks; and 6, 12, 18, and 24 months. BMDs at the lumbar spine increased by 3.1% and 10.8% after 1 and 2 years of weekly teriparatide therapy, respectively. The T-score increased significantly at the lumbar spine compared to baseline after 2 years of therapy (P = .015). Serum P1NP levels increased significantly at 6 months (P = .024), peaked at 1 year, and remained above the baseline even after 2 years. Serum CTx levels decreased significantly at 6 months (P = .025) and remained below baseline after 2 years of teriparatide therapy. Weekly teriparatide therapy (60 μg) appears to be as effective as daily teriparatide for the treatment of PMO by extending the anabolic bone window. AE = adverse event; BMD = bone mineral density; BTM = bone turnover marker; CTx = C-terminal telopeptide of type 1 collagen; DXA = dual-energy X-ray absorptiometry; iPTH = intact parathyroid hormone; P1NP = type 1 collagen C-terminal propeptide; PMO = postmenopausal osteoporosis.

ΔNp63 promotes pediatric neuroblastoma and osteosarcoma by regulating tumor angiogenesis

PubMed Central

Bid, Hemant K.; Roberts, Ryan D.; Cam, Maren; Audino, Anthony; Kurmasheva, Raushan T.; Lin, Jiayuh; Houghton, Peter J.; Cam, Hakan

2013-01-01

The tumor suppressor gene p53 and its family members p63/p73 are critical determinants of tumorigenesis. ΔNp63 is a splice variant of p63, which lacks the N-terminal transactivation domain. It is thought to antagonize p53-, p63- and p73- dependent translation, thus blocking their tumor suppressor activity. In our studies of the pediatric solid tumors neuroblastoma and osteosarcoma, we find overexpression of ΔNp63; however, there is no correlation of ΔNp63 expression with p53 mutation status. Our data suggest that ΔNp63 itself endows cells with a gain of function that leads to malignant transformation, a function independent of any p53 antagonism. Here, we demonstrate that ΔNp63 overexpression, independent of p53, increases secretion of interleukin-6 (IL-6) and interleukin-8 (IL-8), leading to elevated phosphorylation of STAT-3 (Tyr-705). We show that elevated phosphorylation of STAT-3 leads to stabilization of HIF-1α protein, resulting in VEGF secretion. We also show human clinical data, which suggests a mechanistic role for ΔNp63 in osteosarcoma metastasis. In summary, our studies reveal the mechanism by which ΔNp63, as a master transcription factor, modulates tumor angiogenesis. PMID:24154873

The Metalloprotease of Listeria monocytogenes Is Regulated by pH▿

PubMed Central

Forster, Brian M.; Bitar, Alan Pavinski; Slepkov, Emily R.; Kota, Karthik J.; Sondermann, Holger; Marquis, Hélène

2011-01-01

Listeria monocytogenes is an intracytosolic bacterial pathogen. Among the factors contributing to escape from vacuoles are a phosphatidylcholine phospholipase C (PC-PLC) and a metalloprotease (Mpl). Both enzymes are translocated across the bacterial membrane as inactive proproteins, whose propeptides serve in part to maintain them in association with the bacterium. We have shown that PC-PLC maturation is regulated by Mpl and pH and that Mpl maturation occurs by autocatalysis. In this study, we tested the hypothesis that Mpl activity is pH regulated. To synchronize the effect of pH on bacteria, the cytosolic pH of infected cells was manipulated immediately after radiolabeling de novo-synthesized bacterial proteins. Immunoprecipitation of secreted Mpl from host cell lysates revealed the presence of the propeptide and catalytic domain in samples treated at pH 6.5 but not at pH 7.3. The zymogen was present in small amounts under all conditions. Since proteases often remain associated with their respective propeptide following autocatalysis, we aimed at determining whether pH regulates autocatalysis or secretion of the processed enzyme. For this purpose, we used an Mpl construct that contains a Flag tag at the N terminus of its catalytic domain and antibodies that can distinguish N-terminal and non-N-terminal Flag. By fluorescence microscopy, we observed the Mpl zymogen associated with the bacterium at physiological pH but not following acidification. Mature Mpl was not detected in association with the bacterium at either pH. Using purified proteins, we determined that processing of the PC-PLC propeptide by mature Mpl is also pH sensitive. These results indicate that pH regulates the activity of Mpl on itself and on PC-PLC. PMID:21803995

Temperature coefficients and radiation induced DLTS spectra of MOCVD grown n(+)p InP solar cells

NASA Technical Reports Server (NTRS)

Walters, Robert J.; Statler, Richard L.; Summers, Geoffrey P.

1991-01-01

The effects of temperature and radiation on n(+)p InP solar cells and mesa diodes grown by metallorganic chemical vapor deposition (MOCVD) were studied. It was shown that MOCVD is capable of consistently producing good quality InP solar cells with Eff greater than 19 percent which display excellent radiation resistance due to minority carrier injection and thermal annealing. It was also shown that universal predictions of InP device performance based on measurements of a small group of test samples can be expected to be quite accurate, and that the degradation of an InP device due to any incident particle spectrum should be predictable from a measurement following a single low energy proton irradiation.

An N-terminal fragment of substance P, substance P(1-7), down-regulates neurokinin-1 binding in the mouse spinal cord.

PubMed

Yukhananov RYu; Larson, A A

1994-08-29

Injected intrathecally, substance P (SP) down-regulates neurokinin-1 (NK-1) binding in the spinal cord and desensitizes rats to the behavioral effect of SP. N-terminal fragments of SP, such as SP(1-7), induce antinociception and play a role in desensitization to SP in mice. The goal of this study was to assess the abilities of N- and C-terminal fragments of SP to down-regulate NK-1 binding. Binding of [3H]SP to mouse spinal cord membranes was inhibited by SP, CP-96,345, and to a lesser extent by SP(5-11), but not SP(1-7), consistent with these binding sites being NK-1 receptors. Injection of SP(5-11) intrathecally did not affect the affinity (Kd) or concentration (Bmax) of [3H]SP binding. However, injection of 1 nmol of SP(1-7) decreased the Bmax of [3H]SP binding in the spinal cord at 6 h after its injection just as this dose of SP decreased the Bmax at 24 h. These data suggest that the N-terminus of SP is responsible for down-regulation of NK-1 binding. As SP(5-11) did not down-regulate NK-1 binding, activation of NK-1 sites does not appear necessary or sufficient for down-regulation of SP binding. In contrast, SP(1-7), in spite of its inability to interact with NK-1 sites, did down-regulate SP binding, suggesting an indirect mechanism dissociated from NK-1 receptors.

Changes in N:P stoichiometry influence taxonomic composition and nutritional quality of phytoplankton in the Peruvian upwelling

NASA Astrophysics Data System (ADS)

Hauss, Helena; Franz, Jasmin M. S.; Sommer, Ulrich

2012-10-01

Inorganic dissolved macronutrient (nitrogen, N, and phosphorus, P) supply to surface waters in the eastern tropical South Pacific is influenced by expanding oxygen minimum zones, since N loss occurs due to microbial processes under anoxic conditions while P is increasingly released from the shelf sediments. To investigate the impact of decreasing N:P supply ratios in the Peruvian Upwelling, we conducted nutrient manipulation experiments using a shipboard mesocosm setup with a natural phytoplankton community. In a first experiment, either N or P or no nutrients were added with mesozooplankton present or absent. In a second experiment, initial nutrient concentrations were adjusted to four N:P ratios ranging from 2.5 to 16 using two "high N" and two "high P" levels in combination (i.e., + N, + P, + N and P, no addition). Over six and seven days, respectively, microalgal biomass development as well as nutrient uptake was monitored. Phytoplankton biomass strongly responded to N addition, in both mesozooplankton-grazed and not grazed treatments. The developing diatom bloom in the "high N" exceeded that in the "low N" treatments by a factor of two. No modulation of the total biomass by P-addition was observed, however, species-specific responses were more variable. Notably, some organisms were able to benefit from low N:P fertilization ratios, especially Heterosigma sp. and Phaeocystis globosa which are notorious for forming blooms that are toxic or inadequate for mesozooplankton nutrition. After the decline of the diatom bloom, the relative contribution of unsaturated fatty acid to the lipid content of seston was positively correlated to diatom biomass in the peak bloom, indicating that positive effects of diatom blooms on food quality of the protist community to higher trophic levels remain even after the phytoplankton biomass was incorporated by grazers. Our results indicate an overall N-limitation of the system, especially in the case of dominating diatoms, which were

An alanine residue in human parainfluenza virus type 3 phosphoprotein is critical for restricting excessive N0-P interaction and maintaining N solubility.

PubMed

Zhang, Shengwei; Cheng, Qi; Luo, Chenxi; Yin, Lei; Qin, Yali; Chen, Mingzhou

2018-05-01

The phosphoprotein (P) of human parainfluenza virus type 3 (HPIV3) plays a pivotal role in viral RNA synthesis, which interacts with the nucleoprotein (N) to form a soluble N 0 -P complex (N 0 , free of RNAs) to prevent the nonspecific RNA binding and illegitimate aggregation of N. Functional regions within P have been studied intensively. However, the precise site (s) within P directly involved in N 0 -P interaction still remains unclear. In this study, using a series of deleted and truncated mutants of P of HPIV3, we demonstrate that amino-terminal 40 amino acids (aa) of P restrict and regulate N 0 -P interaction. Furthermore, using in vivo HPIV3 minigenome replicon assay, we identify a critical P mutant (P A28P ) located in amino-terminal 40 aa, which fails to support RNA synthesis of HPIV3 minigenome replicon. Although P A28P maintains an enhanced N-P interaction, it is unable to form N 0 -P complex and keep N soluble, thus, resulting in aggregation and functional abolishment of N-P complex. Moreover, we found that recombinant HPIV3 with mutation of A28P in P failed to be rescued. Taken together, we identified a residue within the extreme amino-terminus of P, which plays a critical role in restricting the excessively N-P interaction and keeping a functional N 0 -P complex formation. Copyright © 2018 Elsevier Inc. All rights reserved.

The N-terminal domain of substance P is required for complete homologous desensitization but not phosphorylation of the rat neurokinin-1 receptor.

PubMed

Vigna, S R

2001-02-01

The agonist activity of substance P (SP) is a function of the C-terminal domain of the peptide. A C-terminal SP fragment (SP(6-11)) and analog (septide) and neurokinin A (NKA; a related tachykinin with a divergent N-terminal amino acid sequence) were found to be full neurokinin-1 receptor (NK-1R) agonists, but were not able to desensitize the receptor maximally as much as SP. Substance P caused 95.6 +/- 0.9% maximal desensitization of the NK-1R whereas SP(6-11), septide, and NKA(only)caused 74 +/- 3.5, 50.6 +/- 8, and 71.5 +/- 4.4% maximal desensitization, respectively (mean +/- SEM; P < 0.001 vs SP). When a series of SP C-terminal fragment peptides were tested for their NK-1R desensitizing activity, it was found that SP(5-11)and SP(6-11)caused significantly less maximal NK-1R desensitization than SP. SP N-terminal fragment peptides had no effect on the ability of SP(6-11)to compete with(3)H-SP binding, generate an IP(3)response, or cause NK-1R desensitization when tested with or without SP(6-11). SP, SP(6-11), septide, and NKA all maximally stimulated 8-9-fold increases in NK-1R phosphorylation. When attached to the C-terminal domain of SP responsible for NK-1R binding and agonism, the N-terminus of SP is responsible for 25-50% of homologous desensitization and this may occur via a mechanism other than NK-1R phosphorylation. Copyright 2001 Harcourt Publishers Ltd.

pH-Triggered Molecular Alignment for Reproducible SERS Detection via an AuNP/Nanocellulose Platform

PubMed Central

Wei, Haoran; Vikesland, Peter J.

2015-01-01

The low affinity of neutral and hydrophobic molecules towards noble metal surfaces hinders their detection by surface-enhanced Raman spectroscopy (SERS). Herein, we present a method to enhance gold nanoparticle (AuNP) surface affinity by lowering the suspension pH below the analyte pKa. We developed an AuNP/bacterial cellulose (BC) nanocomposite platform and applied it to two common pollutants, carbamazepine (CBZ) and atrazine (ATZ) with pKa values of 2.3 and 1.7, respectively. Simple mixing of the analytes with AuNP/BC at pH < pKa resulted in consistent electrostatic alignment of the CBZ and ATZ molecules across the nanocomposite and highly reproducible SERS spectra. Limits of detection of 3 nM and 11 nM for CBZ and ATZ, respectively, were attained. Tests with additional analytes (melamine, 2,4-dichloroaniline, 4-chloroaniline, 3-bromoaniline, and 3-nitroaniline) further illustrate that the AuNP/BC platform provides reproducible analyte detection and quantification while avoiding the uncontrolled aggregation and flocculation of AuNPs that often hinder low pH detection. PMID:26658696

pH-Triggered Molecular Alignment for Reproducible SERS Detection via an AuNP/Nanocellulose Platform

NASA Astrophysics Data System (ADS)

Wei, Haoran; Vikesland, Peter J.

2015-12-01

The low affinity of neutral and hydrophobic molecules towards noble metal surfaces hinders their detection by surface-enhanced Raman spectroscopy (SERS). Herein, we present a method to enhance gold nanoparticle (AuNP) surface affinity by lowering the suspension pH below the analyte pKa. We developed an AuNP/bacterial cellulose (BC) nanocomposite platform and applied it to two common pollutants, carbamazepine (CBZ) and atrazine (ATZ) with pKa values of 2.3 and 1.7, respectively. Simple mixing of the analytes with AuNP/BC at pH < pKa resulted in consistent electrostatic alignment of the CBZ and ATZ molecules across the nanocomposite and highly reproducible SERS spectra. Limits of detection of 3 nM and 11 nM for CBZ and ATZ, respectively, were attained. Tests with additional analytes (melamine, 2,4-dichloroaniline, 4-chloroaniline, 3-bromoaniline, and 3-nitroaniline) further illustrate that the AuNP/BC platform provides reproducible analyte detection and quantification while avoiding the uncontrolled aggregation and flocculation of AuNPs that often hinder low pH detection.

Radiation damage in lithium-counterdoped n/p silicon solar cells

NASA Technical Reports Server (NTRS)

Hermann, A. M.; Swartz, C. K.; Brandhorst, H. W., Jr.; Weinberg, I.

1980-01-01

Lithium counterdoped n+/p silicon solar cells were irradiated with 1 MV electrons and their post irradiation performance and low temperature annealing properties were compared to that of the 0.35 ohm cm control cells. Cells fabricated from float zone and Czochralski grown silicon were investigated. It was found that the float zone cells exhibited superior radiation resistance compared to the control cells, while no improvement was noted for the Czochralski grown cells. Room temperature and 60 C annealing studies were conducted. The annealing was found to be a combination of first and second order kinetics for short times. It was suggested that the principal annealing mechanism was migration of lithium to a radiation induced defect with subsequent neutralization of the defect by combination with lithium. The effects of base lithium gradient were investigated. It was found that cells with negative base lithium gradients exhibited poor radiation resistance and performance compared to those with positive or no lithium gradients; the latter being preferred for overall performance and radiation resistance.

Extrapolation of astrophysical S factors for the reaction {sup 14}N((p, {gamma}) {sup 15}O to near-zero energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artemov, S. V.; Igamov, S. B., E-mail: igamov@inp.uz; Tursunmakhatov, Q. I.

2012-03-15

The astrophysical S factors for the radiative-capture reaction {sup 14}N(p, {gamma}){sup 15}O in the region of ultralow energies were calculated on the basis of the R-matrix approach. The values of the radiative and protonic widths were fitted to new experimental data. The contribution of direct radiative capture to bound states of the {sup 15}O nucleus was determined with the aid of asymptotic normalization coefficients, whose values were refined in the present study on the basis of the results obtained from an analysis of the reaction {sup 14}N({sup 3}He, d){sup 15}O at three different energies of incident helium ions. A valuemore » of S(0) = 1.79 {+-} 0.31 keV b was obtained for the total astrophysical S factor, and the reaction rate was determined for the process {sup 14}N(p, {gamma}){sup 15}O.« less

Disruption of chromosomal locus 1p36 differentially modulates TAp73 and ΔNp73 expression in follicular lymphoma

PubMed Central

Hassan, Hesham M.; Varney, Michelle L.; Jain, Smrati; Weisenburger, Dennis D.; Singh, Rakesh K.; Dave, Bhavana J.

2015-01-01

The TP73 gene is located at the chromosome 1p36 locus that is commonly disrupted or deleted in follicular lymphoma (FL) with poor prognosis. Therefore, we analyzed the expression of the pro-apoptotic TAp73 and anti-apoptotic ΔNp73 isoforms in FL cases with normal or abnormal 1p36. We observed a significant increase in ΔNp73 expression and ΔNp73:TAp73 ratio, lower expression of cleaved caspase-3 and a higher frequency of Ki-67 and PCNA positive cells in FL cases with abnormal 1p36. A negative correlation between the ΔNp73:TAp73 ratio and cleaved caspase-3 expression, and a positive correlation between ΔNp73 expression and Ki-67 or PCNA were observed. The expression of TAp73 and its pro-apoptotic transcriptional targets Bim, Puma, and Noxa were significantly lower in FL compared to reactive follicular hyperplasia. Together, our data demonstrates that 1p36 disruption is associated with increased ΔNp73 expression, decreased apoptosis and increased proliferation in FL. PMID:24660851

Observations of rapid changes in N:P ratio associated with non-Redfield nutrient utilization in mesoscale eddies in the upper ocean

NASA Astrophysics Data System (ADS)

Dai, M.; Xu, Y.; Kao, S. J.; Huang, B.; Sun, J.; Sun, Z.

2016-02-01

The concept of Redfield Ratio,or the ocean's nutrient stoichiometry has been fundamental to understanding the ocean biogeochemistry, reflecting the balance of elements between the organisms and the chemical environment and thereby modulating to a large extent the metabolic status of an ecosystem as well as the ecosystem structure. Nutrient stoichiometry of the deep ocean as a consequence of the organic matter regeneration therein is very much homogeneous worldwide while at the upper ocean, changes in nutrient stoichiometryas being frequently observed are to be better understood in terms of their mechanism. Here we report direct observations of fast on a weekly time scale and large fluctuations of nitrate+nitrite (N+N) to soluble reactive phosphorus (SRP) ratios in the ambient seawater in responding to development of meso-scale eddies in an oligotrophic sea, the South China Sea. At the spin up and/or matured stages of eddies, the N:P ratio fluctuated up to 44 in the upper 100 m water column. Along the decay of theeddy, N:P ratio declined back to 3- 20; similar to a "no eddy" condition of 4-22. Along with the fluctuations of N:P ratio was the diatom dominance with the eddy development, while the community structure of the region in typical or non-eddy conditions was predominated by the pico-/nano-plankton as revealed by both the taxa identification and biogenic silicate measurements. This fast growing diatom group apparently had lower nutrient utilization of nitrogenrelative to silicate and/or phosphorus, augmenting the ambient seawater N:P and N:Si. Such preferential P utilization therefore by the fast growing diatomsresulted in significant variations during the different stages of the eddy development.

Functional verification of a porcine myostatin propeptide mutant.

PubMed

Ma, Dezun; Jiang, Shengwang; Gao, Pengfei; Qian, Lili; Wang, Qingqing; Cai, Chunbo; Xiao, Gaojun; Yang, Jinzeng; Cui, Wentao

2015-10-01

Myostatin is a member of TGF-β superfamily that acts as a key negative regulator in development and growth of embryonic and postnatal muscles. In this study, the inhibitory activities of recombinant porcine myostatin propeptide and its mutated form (at the cleavage site of metalloproteinases of BMP-1/TLD family) against murine myostatin was evaluated in vivo by intraperitoneal injection into mice. Results showed that both wild type and mutated form of porcine propeptide significantly inhibited myostatin activity in vivo. The average body weight of mice receiving wild type propeptide or its mutated form increased by 12.5 % and 24.14%, respectively, compared to mice injected with PBS, implying that the in vivo efficacy of porcine propeptide mutant is greater than its wild type propeptide. Transgenic mice expressing porcine myostatin propeptide mutant were generated to further verify the results obtained from mice injected with recombinant porcine propeptide mutant. Compared with wild type (non-transgenic) mice, relative weight of gastrocnemius, rectusfemoris, and tibialis anterior increased by 22.14 %, 34.13 %, 25.37%, respectively, in transgenic male mice, and by 19.90 %, 42.47 %, 45.61%, respectively, in transgenic female mice. Our data also demonstrated that the mechanism by which muscle growth enhancement is achieved by these propeptides is due to an increase in fiber sizes, not by an increase in number of fiber cells.

Effect of rosiglitazone, metformin, and glyburide on bone biomarkers in patients with type 2 diabetes.

PubMed

Zinman, Bernard; Haffner, Steven M; Herman, William H; Holman, Rury R; Lachin, John M; Kravitz, Barbara G; Paul, Gitanjali; Jones, Nigel P; Aftring, R Paul; Viberti, Giancarlo; Kahn, Steven E

2010-01-01

An increase in bone fractures has been observed in women taking thiazolidinediones. The objective of the study was to examine whether changes in circulating bone biomarkers provide insight into the underlying mechanisms responsible for the increase in bone fractures in female participants randomized to rosiglitazone in A Diabetes Outcome Progression Trial (ADOPT). Paired stored baseline and 12-month serum samples were available from 1605 participants (689 women, 916 men) in ADOPT, a long-term clinical trial comparing the effects of rosiglitazone, glyburide, and metformin on glycemic control in patients with type 2 diabetes. This subset was well matched to the total ADOPT study population. In women a marker of osteoclast activity, C-terminal telopeptide (for type 1 collagen), increased by 6.1% with rosiglitazone compared with reductions of 1.3% (P = 0.03 vs. rosiglitazone) and 3.3% (P = 0.002 vs. rosiglitazone) with metformin and glyburide, respectively. In men, C-terminal telopeptide was unchanged on rosiglitazone (-1.0%) and fell on metformin (-12.7%; P < 0.001) and glyburide (-4.3%, P = NS). Markers of osteoblast activity, procollagen type 1 N-propeptide (P1NP) and bone alkaline phosphatase, were reduced for women and men in almost all treatment groups, with the greatest changes in the metformin group (P1NP in females, -14.4%; P1NP in males, -19.3%), intermediate for rosiglitazone (P1NP in females, -4.4%; P1NP in males, -14.4%), and smallest for glyburide (P1NP in males, +0.2%; bone alkaline phosphatase in females, -11.6%). Commonly measured bone biomarkers suggest that changes in bone resorption may be partly responsible for the increased risk of fracture in women taking thiazolidinediones.

Effect of N:P ratio of influent on biomass, nutrient allocation, and recovery of Typha latifolia and Canna 'Bengal Tiger' in a laboratory-scale constructed wetland

USDA-ARS?s Scientific Manuscript database

Constructed wetlands (CWs) are an effective low-technology approach for treating agricultural, industrial, and municipal wastewater. Recovery of phosphorous by constructed wetland plants may be affected by wastewater nitrogen to phosphorous (N:P) ratios. Varying N:P ratios were supplied to Canna '...

Determination of the pKa of the N-terminal amino group of ubiquitin by NMR

PubMed Central

Oregioni, Alain; Stieglitz, Benjamin; Kelly, Geoffrey; Rittinger, Katrin; Frenkiel, Tom

2017-01-01

Ubiquitination regulates nearly every aspect of cellular life. It is catalysed by a cascade of three enzymes and results in the attachment of the C-terminal carboxylate of ubiquitin to a lysine side chain in the protein substrate. Chain extension occurs via addition of subsequent ubiquitin molecules to either one of the seven lysine residues of ubiquitin, or via its N-terminal α-amino group to build linear ubiquitin chains. The pKa of lysine side chains is around 10.5 and hence E3 ligases require a mechanism to deprotonate the amino group at physiological pH to produce an effective nucleophile. In contrast, the pKa of N-terminal α-amino groups of proteins can vary significantly, with reported values between 6.8 and 9.1, raising the possibility that linear chain synthesis may not require a general base. In this study we use NMR spectroscopy to determine the pKa for the N-terminal α-amino group of methionine1 of ubiquitin for the first time. We show that it is 9.14, one of the highest pKa values ever reported for this amino group, providing a rational for the observed need for a general base in the E3 ligase HOIP, which synthesizes linear ubiquitin chains. PMID:28252051

Cold-Adapted Influenza and Recombinant Adenovirus Vaccines Induce Cross-Protective Immunity against pH1N1 Challenge in Mice

PubMed Central

Soboleski, Mark R.; Gabbard, Jon D.; Price, Graeme E.; Misplon, Julia A.; Lo, Chia-Yun; Perez, Daniel R.; Ye, Jianqiang; Tompkins, S. Mark; Epstein, Suzanne L.

2011-01-01

Background The rapid spread of the 2009 H1N1 pandemic influenza virus (pH1N1) highlighted problems associated with relying on strain-matched vaccines. A lengthy process of strain identification, manufacture, and testing is required for current strain-matched vaccines and delays vaccine availability. Vaccines inducing immunity to conserved viral proteins could be manufactured and tested in advance and provide cross-protection against novel influenza viruses until strain-matched vaccines became available. Here we test two prototype vaccines for cross-protection against the recent pandemic virus. Methodology/Principal Findings BALB/c and C57BL/6 mice were intranasally immunized with a single dose of cold-adapted (ca) influenza viruses from 1977 or recombinant adenoviruses (rAd) expressing 1934 nucleoprotein (NP) and consensus matrix 2 (M2) (NP+M2-rAd). Antibodies against the M2 ectodomain (M2e) were seen in NP+M2-rAd immunized BALB/c but not C57BL/6 mice, and cross-reacted with pH1N1 M2e. The ca-immunized mice did not develop antibodies against M2e. Despite sequence differences between vaccine and challenge virus NP and M2e epitopes, extensive cross-reactivity of lung T cells with pH1N1 peptides was detected following immunization. Both ca and NP+M2-rAd immunization protected BALB/c and C57BL/6 mice against challenge with a mouse-adapted pH1N1 virus. Conclusion/Significance Cross-protective vaccines such as NP+M2-rAd and ca virus are effective against pH1N1 challenge within 3 weeks of immunization. Protection was not dependent on recognition of the highly variable external viral proteins and could be achieved with a single vaccine dose. The rAd vaccine was superior to the ca vaccine by certain measures, justifying continued investigation of this experimental vaccine even though ca vaccine is already available. This study highlights the potential for cross-protective vaccines as a public health option early in an influenza pandemic. PMID:21789196

Betavoltaic p--n+-structure simulation

NASA Astrophysics Data System (ADS)

Urchuk, S. U.; Murashev, V. N.; Legotin, S. A.; Krasnov, A. A.; Rabinovich, O. I.; Kuzmina, K. A.; Omel'chenko, Y. K.; Osipov, U. V.; Didenko, S. I.

2016-08-01

In order to increase the betavoltaic batteries efficiency output characteristics of the p--n+ (n--p+) - structures were simulated. Replacing the p+-n-structures on the p-n+ and n-p+ -structures enables the space-charge expansion to the crystal surface and thus to reduce the recombination loss in the heavy doped p+-layer and improve conversion of betavoltaic elements efficiency.

Biomarkers of Inflammation, Thrombogenesis, and Collagen Turnover in Patients With Atrial Fibrillation.

PubMed

Jabati, Sallu; Fareed, Jawed; Liles, Jeffrey; Otto, Abigail; Hoppensteadt, Debra; Bontekoe, Jack; Phan, Trung; Walborn, Amanda; Syed, Mushabbar

2018-07-01

The purpose of this study was to determine whether there are any differences in the levels of inflammatory, thrombotic, and collagen turnover biomarkers between individuals with atrial fibrillation (AF) and healthy volunteers. Circulating plasma levels of plasminogen activator inhibitor 1 (PAI-1), CD40-ligand (CD40-L), nucleosomes (which are indicators of cell death), C-reactive protein (CRP), procollagen III N-terminal propeptide (PIIINP), procollagen III C-terminal propeptide (PIIICP), procollagen I N-terminal propeptide, tissue plasminogen activator, and von Willebrand factor were analyzed as potential biomarkers of AF. Baseline plasma was collected from patients with AF prior to ablation surgery at Loyola University Medical Center. Individuals with AF had statistically significantly increased levels of PAI-1, CD40-L, and nucleosomes, when compared to the normal population ( P < .0001). Additionally, there was a statistically significant increase in the CRP ( P = .01), PIIINP ( P = .04), and PIIICP ( P = .0008) when compared to normal individuals. From this study, it is concluded that the prothrombotic, inflammatory, and collagen turnover biomarkers PAI-1, CD40-L, nucleosomes, CRP, PIIICP, and PIIINP are elevated in AF.

Cell performance and defect behavior in proton-irradiated lithium-counterdoped n(+)p silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Stupica, J. W.; Swartz, C. K.; Goradia, C.

1986-01-01

Lithium-counterdoped n(+)p silicon solar cells were irradiated by 10-MeV protons, and their performance was determined as a function of fluence. It was found that the cell with the highest lithium concentration exhibited the higher radiation resistance. Deep-level transient spectroscopy studies of deep-level defects were used to identify two lithium-related defects. Defect energy levels obtained after the present 10-MeV irradiations were found to be markedly different than those observed after previous 1-MeV electron irradiations. However, the present DLTS data are consistent with previous suggestion by Weinberg et al. (1984) of a lithium-oxygen interaction which tends to inhibit formation of an interstitial boron-oxygen defect.

NMR studies of the dynamics of high-spin nitrophorins: comparative studies of NP4 and NP2 at close to physiological pH.

PubMed

Berry, Robert E; Muthu, Dhanasekaran; Yang, Fei; Walker, F Ann

2015-01-20

The β-barrel nitrophorin (NP) heme proteins are found in the saliva of the blood-sucking insect Rhodnius prolixus, which synthesizes and stores nitric oxide (NO) in the salivary glands. NO is bound to iron of the NPs and is released by dilution and an increase in pH when the insect spits its saliva into the tissues of a victim, to aid in obtaining a blood meal. In the adult insect, there are four nitrophorins, NP1-NP4, which have sequence similarities in two pairs, NP1 and NP4 (90% identical) and NP2 and NP3 (80% identical). The available crystal structures of NP4 have been used to propose that pH-dependent changes in the conformation of two loops between adjacent β-strands at the front opening of the protein, the A-B and G-H loops, determine the rate of NO release. At pH 7.3, NP4 releases NO 17 times faster than NP2 does. In this work, the aqua complexes of NP4 and NP2 have been investigated by nuclear magnetic resonance (NMR) relaxation measurements to probe the pico- to nanosecond and micro- to millisecond time scale motions at two pH values, 6.5 and 7.3. It is found that NP4-OH2 is fairly rigid and only residues in the loop regions show dynamics at pH 6.5; at pH 7.3, much more dynamics of the loops and most of the β-strands are observed while the α-helices remain fairly rigid. In comparison, NP2-OH2 shows much less dynamics, albeit somewhat more than that of the previously reported NP2-NO complex [Muthu, D., Berry, R. E., Zhang, H., and Walker, F. A. (2013) Biochemistry 52, 7910-7925]. The reasons for this major difference between NP4 and NP2 are discussed.

NMR Studies of the Dynamics of High-Spin Nitrophorins: Comparative Studies of NP4 and NP2 at Close to Physiological pH

PubMed Central

2015-01-01

The β-barrel nitrophorin (NP) heme proteins are found in the saliva of the blood-sucking insect Rhodnius prolixus, which synthesizes and stores nitric oxide (NO) in the salivary glands. NO is bound to iron of the NPs and is released by dilution and an increase in pH when the insect spits its saliva into the tissues of a victim, to aid in obtaining a blood meal. In the adult insect, there are four nitrophorins, NP1–NP4, which have sequence similarities in two pairs, NP1 and NP4 (90% identical) and NP2 and NP3 (80% identical). The available crystal structures of NP4 have been used to propose that pH-dependent changes in the conformation of two loops between adjacent β-strands at the front opening of the protein, the A–B and G–H loops, determine the rate of NO release. At pH 7.3, NP4 releases NO 17 times faster than NP2 does. In this work, the aqua complexes of NP4 and NP2 have been investigated by nuclear magnetic resonance (NMR) relaxation measurements to probe the pico- to nanosecond and micro- to millisecond time scale motions at two pH values, 6.5 and 7.3. It is found that NP4-OH2 is fairly rigid and only residues in the loop regions show dynamics at pH 6.5; at pH 7.3, much more dynamics of the loops and most of the β-strands are observed while the α-helices remain fairly rigid. In comparison, NP2-OH2 shows much less dynamics, albeit somewhat more than that of the previously reported NP2-NO complex [Muthu, D., Berry, R. E., Zhang, H., and Walker, F. A. (2013) Biochemistry 52, 7910–7925]. The reasons for this major difference between NP4 and NP2 are discussed. PMID:25486224

N- and C-terminal substance P fragments: differential effects on striatal [3H]substance P binding and NK1 receptor internalization.

PubMed

Michael-Titus, A T; Blackburn, D; Connolly, Y; Priestley, J V; Whelpton, R

1999-07-13

N- and C-terminal substance P (SP) fragments increase striatal dopamine outflow at nanomolar concentrations. This contrasts with their low affinity for NK1 receptors. To explore this discrepancy, we investigated the interaction of SP and SP fragments with NK1 sites in fresh striatal slices, the same model used in the functional studies on dopamine outflow. [3H]SP bound specifically to one site (Kd = 6.6 +/- 0.9 nM; Bmax = 12.6 +/- 0.7 fmol/mg protein). [3H]SP binding was displaced by SP (IC50 = 11.8 nM), but not by SP(1-7) or SP(5-11), up to 10 microM. In contrast, 10 nM SP(1-7) or SP(5-11) induced significant internalization of the NK1 receptor, similar to that induced by SP. We suggest that SP fragments have high affinity for an NK1 receptor conformer which is different from that labelled by [3H]SP.

Radiation damage and defect behavior in proton irradiated lithium-counterdoped n+p silicon solar cells

NASA Technical Reports Server (NTRS)

Stupica, John; Goradia, Chandra; Swartz, Clifford K.; Weinberg, Irving

1987-01-01

Two lithium-counterdoped n+p silicon solar cells with different lithium concentrations were irradiated by 10-MeV protons. Cell performance was measured as a function of fluence, and it was found that the cell with the highest concentration of lithium had the highest radiation resistance. Deep level transient spectroscopy which showed two deep level defects that were lithium related. Relating the defect energy levels obtained from this study with those from earlier work using 1-MeV electron irradiation shows no correlation of the defect energy levels. There is one marked similarity: the absence of the boron-interstitial-oxygen-interstitial defect. This consistency strengthens the belief that lithium interacts with oxygen to prevent the formation of the boron interstitial-oxygen interstitial defect. The results indicate that, in general, addition of lithium in small amounts to the p-base of a boron doped silicon solar cell such that the base remains p-type, tends to increase the radiation resistance of the cell.

Photodynamic N-TiO2 Nanoparticle Treatment Induces Controlled ROS-mediated Autophagy and Terminal Differentiation of Leukemia Cells

PubMed Central

Moosavi, Mohammad Amin; Sharifi, Maryam; Ghafary, Soroush Moasses; Mohammadalipour, Zahra; Khataee, Alireza; Rahmati, Marveh; Hajjaran, Sadaf; Łos, Marek J.; Klonisch, Thomas; Ghavami, Saeid

2016-01-01

In this study, we used nitrogen-doped titanium dioxide (N-TiO2) NPs in conjugation with visible light, and show that both reactive oxygen species (ROS) and autophagy are induced by this novel NP-based photodynamic therapy (PDT) system. While well-dispersed N-TiO2 NPs (≤100 μg/ml) were inert, their photo-activation with visible light led to ROS-mediated autophagy in leukemia K562 cells and normal peripheral lymphocytes, and this increased in parallel with increasing NP concentrations and light doses. At a constant light energy (12 J/cm2), increasing N-TiO2 NP concentrations increased ROS levels to trigger autophagy-dependent megakaryocytic terminal differentiation in K562 cells. By contrast, an ROS challenge induced by high N-TiO2 NP concentrations led to autophagy-associated apoptotic cell death. Using chemical autophagy inhibitors (3-methyladenine and Bafilomycin A1), we confirmed that autophagy is required for both terminal differentiation and apoptosis induced by photo-activated N-TiO2. Pre-incubation of leukemic cells with ROS scavengers muted the effect of N-TiO2 NP-based PDT on cell fate, highlighting the upstream role of ROS in our system. In summary, PDT using N-TiO2 NPs provides an effective method of priming autophagy by ROS induction. The capability of photo-activated N-TiO2 NPs in obtaining desirable cellular outcomes represents a novel therapeutic strategy of cancer cells. PMID:27698385

Two assays for measuring fibrosis: reverse transcriptase-polymerase chain reaction of collagen alpha(1) (III) mRNA is an early predictor of subsequent collagen deposition while a novel serum N-terminal procollagen (III) propeptide assay reflects manifest fibrosis in carbon tetrachloride-treated rats.

PubMed

Kauschke, S G; Knorr, A; Heke, M; Kohlmeyer, J; Schauer, M; Theiss, G; Waehler, R; Burchardt, E R

1999-11-15

Using a novel quantitative reverse transcriptase-polymerase chain reaction assay, we have determined the amount of specific mRNA for procollagen alpha(1) (III) (PIIIP) in the carbon tetrachloride (CCl(4)) model of liver fibrosis in rats. After a single week of CCl(4) application, the amount of PIIIP mRNA was increased approximately 10 times over the untreated control group and continued to increase to approximately 30 times after 7 weeks of intoxication. In this model substantial fibrosis was demonstrated by computer-aided morphometry after 5 to 7 weeks of treatment. Using recombinant murine N-terminal procollagen alpha(1) (III) propeptide (PIIINP), a novel sensitive immunoassay for the measurement of circulating PIIINP in rodent sera was established. An increase in PIIINP serum levels was observed after 5 to 7 weeks of CCl(4) intoxication. Our results suggest PIIIP gene expression is an early marker of tissue fibrosis. Early PIIIP gene expression is correlated with the extent of the subsequent fibrosis. PIIIP mRNA levels increase much earlier than conventional histological examination or PIIINP levels. PIIINP measurements with our new serum assay, on the other hand, are a good noninvasive marker of manifest fibrosis but are a poor marker of fibrogenesis. Copyright 1999 Academic Press.

The α-Secretase-derived N-terminal Product of Cellular Prion, N1, Displays Neuroprotective Function in Vitro and in Vivo*

PubMed Central

Guillot-Sestier, Marie-Victoire; Sunyach, Claire; Druon, Charlotte; Scarzello, Sabine; Checler, Frédéric

2009-01-01

Cellular prion protein (PrPc) undergoes a disintegrin-mediated physiological cleavage, generating a soluble amino-terminal fragment (N1), the function of which remained unknown. Recombinant N1 inhibits staurosporine-induced caspase-3 activation by modulating p53 transcription and activity, whereas the PrPc-derived pathological fragment (N2) remains biologically inert. Furthermore, N1 protects retinal ganglion cells from hypoxia-induced apoptosis, reduces the number of terminal deoxynucleotidyltransferase-mediated biotinylated UTP nick end labeling-positive and p53-immunoreactive neurons in a pressure-induced ischemia model of the rat retina and triggers a partial recovery of b-waves but not a-waves of rat electroretinograms. Our work is the first demonstration that the α-secretase-derived PrPc fragment N1, but not N2, displays in vivo and in vitro neuroprotective function by modulating p53 pathway. It further demonstrates that distinct N-terminal cleavage products of PrPc harbor different biological activities underlying the various phenotypes linking PrPc to cell survival. PMID:19850936

Ionization of nS, nP, and nD lithium, potassium, and cesium Rydberg atoms by blackbody radiation

NASA Astrophysics Data System (ADS)

Beterov, I. I.; Ryabtsev, I. I.; Tretyakov, D. B.; Bezuglov, N. N.; Ékers, A.

2008-07-01

The results of theoretical calculations of the blackbody ionization rates of lithium, potassium, and cesium atoms residing in Rydberg states are presented. The calculations are performed for nS, nP, and nD states in a wide range of principal quantum numbers, n = 8-65, for blackbody radiation temperatures T = 77, 300, and 600 K. The calculations are performed using the known quasi-classical formulas for the photoionization cross sections and for the radial matrix elements of transitions in the discrete spectrum. The effect of the blackbody-radiation-induced population redistribution between Rydberg states on the blackbody ionization rates measured under laboratory conditions is quantitatively analyzed. Simple analytical formulas that approximate the numerical results and that can be used to estimate the blackbody ionization rates of Rydberg atoms are presented. For the S series of lithium, the rate of population of high-lying Rydberg levels by blackbody radiation is found to anomalously behave as a function of n. This anomaly is similar to the occurrence of the Cooper minimum in the discrete spectrum.

The C-terminal propeptide of a plant defensin confers cytoprotective and subcellular targeting functions

PubMed Central

2014-01-01

Background Plant defensins are small (45–54 amino acids), basic, cysteine-rich proteins that have a major role in innate immunity in plants. Many defensins are potent antifungal molecules and are being evaluated for their potential to create crop plants with sustainable disease resistance. Defensins are produced as precursor molecules which are directed into the secretory pathway and are divided into two classes based on the absence (class I) or presence (class II) of an acidic C-terminal propeptide (CTPP) of about 33 amino acids. The function of this CTPP had not been defined. Results By transgenically expressing the class II plant defensin NaD1 with and without its cognate CTPP we have demonstrated that NaD1 is phytotoxic to cotton plants when expressed without its CTPP. Transgenic cotton plants expressing constructs encoding the NaD1 precursor with the CTPP had the same morphology as non-transgenic plants but expression of NaD1 without the CTPP led to plants that were stunted, had crinkled leaves and were less viable. Immunofluorescence microscopy and transient expression of a green fluorescent protein (GFP)-CTPP chimera were used to confirm that the CTPP is sufficient for vacuolar targeting. Finally circular dichroism and NMR spectroscopy were used to show that the CTPP adopts a helical confirmation. Conclusions In this report we have described the role of the CTPP on NaD1, a class II defensin from Nicotiana alata flowers. The CTPP of NaD1 is sufficient for vacuolar targeting and plays an important role in detoxification of the defensin as it moves through the plant secretory pathway. This work may have important implications for the use of defensins for disease protection in transgenic crops. PMID:24495600

HABP1/p32/gC1qR induces aberrant growth and morphology in Schizosaccharomyces pombe through its N-terminal {alpha} helix

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mallick, Jaideep; Datta, Kasturi

2005-10-01

Hyaluronan binding protein (HABP1), located on human chromosome 17p13.3, was identified and characterized as being involved in cellular signaling from our laboratory. Here, we demonstrate that HABP1 expression in Schizosaccharomyces pombe induces growth inhibition, morphological abnormalities like elongation, multinucleation and aberrant cell septum formation in several strains of S. pombe, implicating its role in cell cycle progression and cytokinesis. This argument is further strengthened by an observed delay in the maximal expression of cell cycle regulatory proteins like CDC 2 and CDC 25 coupled to the direct interaction of HABP1 with CDC 25. In order to pinpoint the interacting domainmore » of HABP1, its N- and C-terminal truncated variants ({delta}N.HABP1 and {delta}C.HABP1, respectively) were utilized which revealed that while expression of the former did not alter the phenotype, the latter generated morphological changes similar to those imparted upon HABP1 expression. It was also noted that along with HABP1, {delta}C.HABP1 too directly interacts with CDC 25 while {delta}N.HABP1 does not. Taken together, these data suggest that HABP1 induces morphological changes and modulates the cell cycle by interacting with proteins like CDC 25 through its N-terminal {alpha}-helix.« less

Quasiclassical calculations of blackbody-radiation-induced depopulation rates and effective lifetimes of Rydberg nS, nP, and nD alkali-metal atoms with n{<=}80

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beterov, I. I.; Ryabtsev, I. I.; Tretyakov, D. B.

2009-05-15

Rates of depopulation by blackbody radiation (BBR) and effective lifetimes of alkali-metal nS, nP, and nD Rydberg states have been calculated in a wide range of principal quantum numbers n{<=}80 at the ambient temperatures of 77, 300, and 600 K. Quasiclassical formulas were used to calculate the radial matrix elements of the dipole transitions from Rydberg states. Good agreement of our numerical results with the available theoretical and experimental data has been found. We have also obtained simple analytical formulas for estimates of effective lifetimes and BBR-induced depopulation rates, which well agree with the numerical data.

The N-terminal domain of the mammalian nucleoporin p62 interacts with other nucleoporins of the FXFG family during interphase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stochaj, Ursula; Banski, Piotr; Kodiha, Mohamed

2006-08-01

Nuclear pore complexes (NPCs) provide the only sites for macromolecular transport between nucleus and cytoplasm. The nucleoporin p62, a component of higher eukaryotic NPCs, is located at the central gated channel and involved in nuclear trafficking of various cargos. p62 is organized into an N-terminal segment that contains FXFG repeats and binds the soluble transport factor NTF2, whereas the C-terminal portion associates with other nucleoporins and importin-{beta}1. We have now identified new components that interact specifically with the p62 N-terminal domain. Using the p62 N-terminal segment as bait, we affinity-purified nucleoporins Nup358, Nup214 and Nup153 from crude cell extracts. Inmore » ligand binding assays, the N-terminal p62 segment associated with Nup358 and p62, suggesting their direct binding to the p62 N-terminal portion. Furthermore, p62 was isolated in complex with Nup358, Nup214 and Nup153 from growing HeLa cells, indicating that the interactions Nup358/p62, Nup214/p62 and p62/Nup153 also occur in vivo. The formation of Nup358/p62 and p62/Nup153 complexes was restricted to interphase cells, whereas Nup214/p62 binding was detected in interphase as well as during mitosis. Our results support a model of complex interactions between FXFG containing nucleoporins, and we propose that some of these interactions may contribute to the movement of cargo across the NPC.« less

Bone Turnover with Venlafaxine Treatment in Older Adults with Depression.

PubMed

Rawson, Kerri S; Dixon, David; Civitelli, Roberto; Peterson, Tim R; Mulsant, Benoit H; Reynolds, Charles F; Lenze, Eric J

2017-09-01

Epidemiologic data suggest older adults receiving serotonergic antidepressants may have accelerated bone loss. We examined bone turnover marker changes and patient-level variables associated with these changes in older adults receiving protocolized antidepressant treatment. Open-label, protocolized treatment study. Medical centers in Pittsburgh, St Louis, and Toronto. Older adults with major depression (N = 168). Serum levels of the bone resorption marker C-terminal cross-linking telopeptide of type 1 collagen (CTX) and the bone formation marker procollagen type 1 N propeptide (P1NP) were assayed before and after 12 weeks of treatment with venlafaxine. Whether CTX and P1NP changes were associated with depression remission and duration of depression and genetic polymorphisms in the serotonin transporter (5HTTLPR) and 1B receptor (HTR1B) were also examined. CTX increased and P1NP decreased during venlafaxine treatment, a profile consistent with accelerated bone loss. Two individual-level clinical variables were correlated with bone turnover; participants whose depression did not go into remission had higher CTX levels, and those with chronic depression had lower P1NP levels. HTR1B genotype predicted P1NP change, whereas 5HTTLPR genotype was unrelated to either biomarker. Bone turnover markers change with antidepressant treatment in a pattern that suggests accelerated bone loss, although the clinical significance of these changes is unclear. These data are preliminary and argue for a larger, controlled study to confirm whether antidepressants are harmful to bone metabolism and whether certain individuals might be at increased risk. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

In-Operando Spatial Imaging of Edge Termination Electric Fields in GaN Vertical p-n Junction Diodes

DOE PAGES

Leonard, Francois; Dickerson, J. R.; King, M. P.; ...

2016-05-03

Control of electric fields with edge terminations is critical to maximize the performance of high-power electronic devices. We proposed a variety of edge termination designs which makes the optimization of such designs challenging due to many parameters that impact their effectiveness. And while modeling has recently allowed new insight into the detailed workings of edge terminations, the experimental verification of the design effectiveness is usually done through indirect means, such as the impact on breakdown voltages. In this letter, we use scanning photocurrent microscopy to spatially map the electric fields in vertical GaN p-n junction diodes in operando. We alsomore » reveal the complex behavior of seemingly simple edge termination designs, and show how the device breakdown voltage correlates with the electric field behavior. Modeling suggests that an incomplete compensation of the p-type layer in the edge termination creates a bilayer structure that leads to these effects, with variations that significantly impact the breakdown voltage.« less

Associations Between Serum Bone Biomarkers in Early Breast Cancer and Development of Bone Metastasis: Results From the AZURE (BIG01/04) Trial.

PubMed

Brown, Janet; Rathbone, Emma; Hinsley, Samantha; Gregory, Walter; Gossiel, Fatma; Marshall, Helen; Burkinshaw, Roger; Shulver, Helen; Thandar, Hasina; Bertelli, Gianfilippo; Maccon, Keane; Bowman, Angela; Hanby, Andrew; Bell, Richard; Cameron, David; Coleman, Robert

2018-02-07

Adjuvant therapies can prevent/delay bone metastasis development in breast cancer. We investigated whether serum bone turnover markers in early disease have clinical utility in identifying patients with a high risk of developing bone metastasis. Markers of bone formation (N-terminal propeptide of type-1 collagen [P1NP]) and bone resorption (C-telopeptide of type-1 collagen [CTX], pyridinoline cross-linked carboxy-terminal telopeptide of type-1 collagen [1-CTP]) were measured in baseline (pretreatment blood samples from 872 patients from a large randomized trial of adjuvant zoledronic acid (AZURE-ISRCTN79831382) in early breast cancer. Cox proportional hazards regression and cumulative incidence functions (adjusted for factors having a statistically significant effect on outcome) were used to investigate prognostic and predictive associations between recurrence events, bone marker levels, and clinical variables. All statistical tests were two-sided. When considered as continuous variables (log transformed), P1NP, CTX, and 1-CTP were each prognostic for future bone recurrence at any time (P = .006, P = .009, P = .008, respectively). Harrell's c-indices were a P1NP of 0.57 (95% confidence interval [CI] = 0.51 to 0.63), CTX of 0.57 (95% CI = 0.51 to 0.62), and 1-CTP of 0.57 (95% CI = 0.52 to 0.63). In categorical analyses based on the normal range, high baseline P1NP (>70 ng/mL) and CTX (>0.299 ng/mL), but not 1-CTP (>4.2 ng/mL), were also prognostic for future bone recurrence (P = .03, P = .03, P = .10, respectively). None of the markers were prognostic for overall distant recurrence; that is, they were bone metastasis specific, and none of the markers were predictive of treatment benefit from zoledronic acid. Serum P1NP, CTX, and 1-CTP are clinically useful, easily measured markers that show good prognostic ability (though low-to-moderate discrimination) for bone-specific recurrence and are worthy of further study. © The Author(s) 2018. Published by Oxford

Measurement of the n-p elastic scattering angular distribution at E{sub n}=14.9 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boukharouba, N.; Bateman, F. B.; Carlson, A. D.

2010-07-15

The relative differential cross section for the elastic scattering of neutrons by protons was measured at an incident neutron energy E{sub n}=14.9 MeV and for center-of-mass scattering angles ranging from about 60 deg. to 180 deg. Angular distribution values were obtained from the normalization of the integrated data to the n-p total elastic scattering cross section. Comparisons of the normalized data to the predictions of the Arndt et al. phase-shift analysis, those of the Nijmegen group, and with the ENDF/B-VII.0 evaluation are sensitive to the value of the total elastic scattering cross section used to normalize the data. The resultsmore » of a fit to a first-order Legendre polynomial expansion are in good agreement in the backward scattering hemisphere with the predictions of the Arndt et al. phase-shift analysis, those of the Nijmegen group, and to a lesser extent, with the ENDF/B-VII.0 evaluation. A fit to a second-order expansion is in better agreement with the ENDF/B-VII.0 evaluation than with the other predictions, in particular when the total elastic scattering cross section given by Arndt et al. and the Nijmegen group is used to normalize the data. A Legendre polynomial fit to the existing n-p scattering data in the 14 MeV energy region, excluding the present measurement, showed that a best fit is obtained for a second-order expansion. Furthermore, the Kolmogorov-Smirnov test confirms the general agreement in the backward scattering hemisphere and shows that significant differences between the database and the predictions occur in the angular range between 60 deg. and 120 deg. and below 20 deg. Although there is good overall agreement in the backward scattering hemisphere, more precision small-angle scattering data and a better definition of the total elastic cross section are needed for an accurate determination of the shape and magnitude of the angular distribution.« less

von Willebrand factor (VWF) propeptide binding to VWF D'D3 domain attenuates platelet activation and adhesion.

PubMed

Madabhushi, Sri R; Shang, Chengwei; Dayananda, Kannayakanahalli M; Rittenhouse-Olson, Kate; Murphy, Mary; Ryan, Thomas E; Montgomery, Robert R; Neelamegham, Sriram

2012-05-17

Noncovalent association between the von Willebrand factor (VWF) propeptide (VWFpp) and mature VWF aids N-terminal multimerization and protein compartmentalization in storage granules. This association is currently thought to dissipate after secretion into blood. In the present study, we examined this proposition by quantifying the affinity and kinetics of VWFpp binding to mature VWF using surface plasmon resonance and by developing novel anti-VWF D'D3 mAbs. Our results show that the only binding site for VWFpp in mature VWF is in its D'D3 domain. At pH 6.2 and 10mM Ca(2+), conditions mimicking intracellular compartments, VWFpp-VWF binding occurs with high affinity (K(D) = 0.2nM, k(off) = 8 × 10(-5) s(-1)). Significant, albeit weaker, binding (K(D) = 25nM, k(off) = 4 × 10(-3) s(-1)) occurs under physiologic conditions of pH 7.4 and 2.5mM Ca(2+). This interaction was also observed in human plasma (K(D) = 50nM). The addition of recombinant VWFpp in both flow-chamber-based platelet adhesion assays and viscometer-based shear-induced platelet aggregation and activation studies reduced platelet adhesion and activation partially. Anti-D'D3 mAb DD3.1, which blocks VWFpp binding to VWF-D'D3, also abrogated platelet adhesion, as shown by shear-induced platelet aggregation and activation studies. Our data demonstrate that VWFpp binding to mature VWF occurs in the circulation, which can regulate the hemostatic potential of VWF by reducing VWF binding to platelet GpIbα.

Dichloro-Cycloazatriphosphane: The Missing Link between N2 P2 and P4 Ring Systems in the Systematic Development of NP Chemistry.

PubMed

Bresien, Jonas; Hinz, Alexander; Schulz, Axel; Suhrbier, Tim; Thomas, Max; Villinger, Alexander

2017-10-20

A dichloro-cycloazatriphosphane that incorporates a cyclic NP 3 backbone could be synthesized using knowledge gained from the chemistry of N 2 P 2 and P 4 ring systems. It fills the gap between the congeneric compounds [ClP(μ-NR)] 2 and [ClP(μ-PR)] 2 (R=sterically demanding substituent), and thus contributes to the systematic development of nitrogen-phosphorus chemistry in general. The title compound was studied with respect to its formation via a labile aminodiphosphene, which readily underwent different rearrangement reactions depending on the solvent. All compounds were fully characterized by experimental and computational methods. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Amino-terminal arginylation targets endoplasmic reticulum chaperone BiP for autophagy through p62 binding.

PubMed

Cha-Molstad, Hyunjoo; Sung, Ki Sa; Hwang, Joonsung; Kim, Kyoung A; Yu, Ji Eun; Yoo, Young Dong; Jang, Jun Min; Han, Dong Hoon; Molstad, Michael; Kim, Jung Gi; Lee, Yoon Jee; Zakrzewska, Adriana; Kim, Su-Hyeon; Kim, Sung Tae; Kim, Sun Yong; Lee, Hee Gu; Soung, Nak Kyun; Ahn, Jong Seog; Ciechanover, Aaron; Kim, Bo Yeon; Kwon, Yong Tae

2015-07-01

We show that ATE1-encoded Arg-transfer RNA transferase (R-transferase) of the N-end rule pathway mediates N-terminal arginylation of multiple endoplasmic reticulum (ER)-residing chaperones, leading to their cytosolic relocalization and turnover. N-terminal arginylation of BiP (also known as GRP78), protein disulphide isomerase and calreticulin is co-induced with autophagy during innate immune responses to cytosolic foreign DNA or proteasomal inhibition, associated with increased ubiquitylation. Arginylated BiP (R-BiP) is induced by and associated with cytosolic misfolded proteins destined for p62 (also known as sequestosome 1, SQSTM1) bodies. R-BiP binds the autophagic adaptor p62 through the interaction of its N-terminal arginine with the p62 ZZ domain. This allosterically induces self-oligomerization and aggregation of p62 and increases p62 interaction with LC3, leading to p62 targeting to autophagosomes and selective lysosomal co-degradation of R-BiP and p62 together with associated cargoes. In this autophagic mechanism, Nt-arginine functions as a delivery determinant, a degron and an activating ligand. Bioinformatics analysis predicts that many ER residents use arginylation to regulate non-ER processes.

Photoelectrochemical response of GaN, InGaN, and GaNP nanowire ensembles

NASA Astrophysics Data System (ADS)

Philipps, Jan M.; Hölzel, Sara; Hille, Pascal; Schörmann, Jörg; Chatterjee, Sangam; Buyanova, Irina A.; Eickhoff, Martin; Hofmann, Detlev M.

2018-05-01

The photoelectrochemical responses of GaN, GaNP, and InGaN nanowire ensembles are investigated by the electrical bias dependent photoluminescence, photocurrent, and spin trapping experiments. The results are explained in the frame of the surface band bending model. The model is sufficient for InGaN nanowires, but for GaN nanowires the electrochemical etching processes in the anodic regime have to be considered additionally. These processes lead to oxygen rich surface (GaxOy) conditions as evident from energy dispersive X-ray fluorescence. For the GaNP nanowires, a bias dependence of the carrier transfer to the electrolyte is not reflected in the photoluminescence response, which is tentatively ascribed to a different origin of radiative recombination in this material as compared to (In)GaN. The corresponding consequences for the applications of the materials for water splitting or pH-sensing will be discussed.

Structural basis for substrate recognition by the human N-terminal methyltransferase 1

DOE PAGES

Dong, Cheng; Mao, Yunfei; Tempel, Wolfram; ...

2015-11-05

α-N-terminal methylation represents a highly conserved and prevalent post-translational modification, yet its biological function has remained largely speculative. The recent discovery of α-N-terminal methyltransferase 1 (NTMT1) and its physiological substrates propels the elucidation of a general role of α-N-terminal methylation in mediating DNA-binding ability of the modified proteins. The phenotypes, observed from both NTMT1 knockdown in breast cancer cell lines and knockout mouse models, suggest the potential involvement of α-N-terminal methylation in DNA damage response and cancer development. In this study, we report the first crystal structures of human NTMT1 in complex with cofactor S-adenosyl-L-homocysteine (SAH) and six substrate peptides,more » respectively, and reveal that NTMT1 contains two characteristic structural elements (a β hairpin and an N-terminal extension) that contribute to its substrate specificity. Our complex structures, coupled with mutagenesis, binding, and enzymatic studies, also present the key elements involved in locking the consensus substrate motif XPK (X indicates any residue type other than D/E) into the catalytic pocket for α-N-terminal methylation and explain why NTMT1 prefers an XPK sequence motif. We propose a catalytic mechanism for α-N-terminal methylation. Overall, this study gives us the first glimpse of the molecular mechanism of α-N-terminal methylation and potentially contributes to the advent of therapeutic agents for human diseases associated with deregulated α-N-terminal methylation.« less

N-P Co-Limitation of Primary Production and Response of Arthropods to N and P in Early Primary Succession on Mount St. Helens Volcano

PubMed Central

Bishop, John G.; O'Hara, Niamh B.; Titus, Jonathan H.; Apple, Jennifer L.; Gill, Richard A.; Wynn, Louise

2010-01-01

Background The effect of low nutrient availability on plant-consumer interactions during early succession is poorly understood. The low productivity and complexity of primary successional communities are expected to limit diversity and abundance of arthropods, but few studies have examined arthropod responses to enhanced nutrient supply in this context. We investigated the effects of nitrogen (N) and phosphorus (P) addition on plant productivity and arthropod abundance on 24-yr-old soils at Mount St. Helens volcano. Methodology/Principal Findings We measured the relative abundance of eight arthropod orders and five families in plots that received N, P, or no nutrients for 3–5 years. We also measured plant % cover, leaf %N, and plant diversity. Vegetation responded rapidly to N addition but showed a lagged response to P that, combined with evidence of increased N fixation, suggested P-limitation to N availability. After 3 yrs of fertilization, orthopterans (primarily Anabrus simplex (Tettigoniidae) and Melanoplus spp (Acrididae)) showed a striking attraction to P addition plots, while no other taxa responded to fertilization. After 5 yrs of fertilization, orthopteran density in the same plots increased 80%–130% with P addition and 40% with N. Using structural equation modeling, we show that in year 3 orthopteran abundance was associated with a P-mediated increase in plant cover (or correlated increases in resource quality), whereas in year 5 orthopteran density was not related to cover, diversity or plant %N, but rather to unmeasured effects of P, such as its influence on other aspects of resource quality. Conclusions/Significance The marked surprising response to P by orthopterans, combined with a previous observation of P-limitation in lepidopteran herbivores at these sites, suggests that P-mediated effects of food quantity or quality are critical to insect herbivores in this N-P co-limited primary successional system. Our results also support a previous

Root Responses to Altered Ecosystem N/P Stoichiometry in a Mediterranean Tree-Grass Ecosystem

NASA Astrophysics Data System (ADS)

Nair, Richard; Moreno, Gerado; Morris, Kendalynn; Schrumpf, Marion; Migliavacca, Mirco

2017-04-01

Biological components of the soil system (plant roots, fungi, microbes) may respond to biogeochemical drivers (e.g. nutrient status, water availability, C availability) in dissimilar ways due to differing scales, activities and access to resources. Understanding individual components and their phenology in the soil system is therefore critical to interpret overall fluxes. In seasonally dry systems, plants balance belowground investment with other growth and maintenance in life strategies where water limitations (in dry periods), nutrient limitations (in wet periods) and temperature/light limitations (in winter) interact, varying the need to invest in gaining these three resources throughout the year. Additionally, root growth may also be desynchronized with overall nutrient demand due to the ability to take up nutrients outside of seasonal periods of demand for storage and subsequent reallocation. We examined root responses to an ecosystem level stoichiometry (+N / +N+P) manipulation experiment at a highly instrumented site in a strongly seasonal semi-arid tree-grass ('dehesa') system (Majadas del Tietar, Spain). We are interested in whether root growth and phenology is affected by differing demand for nutrients/water both between sites and at tree and grass-dominated subsites. Many non-invasive, ecosystem-scale methods to measure changes in biogeochemical cycling focus only on integrated whole-system fluxes or above-ground change and it is difficult to extract a root signal. However, local soil respiration fluxes and root growth introduces a variety of method-dependent artefacts and drawbacks necessitating multiple approaches and careful interpretation. Therefore, in coordination with indirect measurements (subcanopy fluxes via eddy covariance, soil respiration chambers) we are using direct soil coring, ingrowth cores and repeatable measurements from custom-built minirhizotron systems to attempt to assess site-level variation in root biomass and phenology. In this

Large bandgap reduced graphene oxide (rGO) based n-p + heterojunction photodetector with improved NIR performance

NASA Astrophysics Data System (ADS)

Singh, Manjri; Kumar, Gaurav; Prakash, Nisha; Khanna, Suraj P.; Pal, Prabir; Singh, Surinder P.

2018-04-01

Integration of two-dimensional reduced graphene oxide (rGO) with conventional Si semiconductor offers novel strategies for realizing broadband photodiode with enhanced device performance. In this quest, we have synthesized large bandgap rGO and fabricated metal-free broadband (300–1100 nm) back-to-back connected np-pn hybrid photodetector utilizing drop casted n-rGO/p +-Si heterojunctions with high performance in NIR region (830 nm). With controlled illumination, the device exhibited a peak responsivity of 16.7 A W‑1 and peak detectivity of 2.56 × 1012 Jones under 830 nm illumination (11 μW cm‑2) at 1 V applied bias with fast response (∼460 μs) and recovery time (∼446 μs). The fabricated device demonstrated excellent repeatability, durability and photoswitching behavior with high external quantum efficiency (∼2.5 × 103%), along with ultrasensitive behavior at low light conditions.

The C-terminal region of Ge-1 presents conserved structural features required for P-body localization.

PubMed

Jinek, Martin; Eulalio, Ana; Lingel, Andreas; Helms, Sigrun; Conti, Elena; Izaurralde, Elisa

2008-10-01

The removal of the 5' cap structure by the DCP1-DCP2 decapping complex irreversibly commits eukaryotic mRNAs to degradation. In human cells, the interaction between DCP1 and DCP2 is bridged by the Ge-1 protein. Ge-1 contains an N-terminal WD40-repeat domain connected by a low-complexity region to a conserved C-terminal domain. It was reported that the C-terminal domain interacts with DCP2 and mediates Ge-1 oligomerization and P-body localization. To understand the molecular basis for these functions, we determined the three-dimensional crystal structure of the most conserved region of the Drosophila melanogaster Ge-1 C-terminal domain. The region adopts an all alpha-helical fold related to ARM- and HEAT-repeat proteins. Using structure-based mutants we identified an invariant surface residue affecting P-body localization. The conservation of critical surface and structural residues suggests that the C-terminal region adopts a similar fold with conserved functions in all members of the Ge-1 protein family.

BDNF Binds Its Pro-Peptide with High Affinity and the Common Val66Met Polymorphism Attenuates the Interaction

PubMed Central

Uegaki, Koichi; Kumanogoh, Haruko; Mizui, Toshiyuki; Hirokawa, Takatsugu; Ishikawa, Yasuyuki; Kojima, Masami

2017-01-01

Most growth factors are initially synthesized as precursors then cleaved into bioactive mature domains and pro-domains, but the biological roles of pro-domains are poorly understood. In the present study, we investigated the pro-domain (or pro-peptide) of brain-derived neurotrophic factor (BDNF), which promotes neuronal survival, differentiation and synaptic plasticity. The BDNF pro-peptide is a post-processing product of the precursor BDNF. Using surface plasmon resonance and biochemical experiments, we first demonstrated that the BDNF pro-peptide binds to mature BDNF with high affinity, but not other neurotrophins. This interaction was more enhanced at acidic pH than at neutral pH, suggesting that the binding is significant in intracellular compartments such as trafficking vesicles rather than the extracellular space. The common Val66Met BDNF polymorphism results in a valine instead of a methionine in the pro-domain, which affects human brain functions and the activity-dependent secretion of BDNF. We investigated the influence of this variation on the interaction between BDNF and the pro-peptide. Interestingly, the Val66Met polymorphism stabilized the heterodimeric complex of BDNF and its pro-peptide. Furthermore, compared with the Val-containing pro-peptide, the complex with the Met-type pro-peptide was more stable at both acidic and neutral pH, suggesting that the Val66Met BDNF polymorphism forms a more stable complex. A computational modeling provided an interpretation to the role of the Val66Met mutation in the interaction of BDNF and its pro-peptide. Lastly, we performed electrophysiological experiments, which indicated that the BDNF pro-peptide, when pre-incubated with BDNF, attenuated the ability of BDNF to inhibit hippocampal long-term depression (LTD), suggesting a possibility that the BDNF pro-peptide may interact directly with BDNF and thereby inhibit its availability. It was previously reported that the BDNF pro-domain exerts a chaperone-like function

Myostatin propeptide gene delivery by gene gun ameliorates muscle atrophy in a rat model of botulinum toxin-induced nerve denervation.

PubMed

Tsai, Sen-Wei; Tung, Yu-Tang; Chen, Hsiao-Ling; Yang, Shang-Hsun; Liu, Chia-Yi; Lu, Michelle; Pai, Hui-Jing; Lin, Chi-Chen; Chen, Chuan-Mu

2016-02-01

Muscle atrophy is a common symptom after nerve denervation. Myostatin propeptide, a precursor of myostatin, has been documented to improve muscle growth. However, the mechanism underlying the muscle atrophy attenuation effects of myostatin propeptide in muscles and the changes in gene expression are not well established. We investigated the possible underlying mechanisms associated with myostatin propeptide gene delivery by gene gun in a rat denervation muscle atrophy model, and evaluated gene expression patterns. In a rat botulinum toxin-induced nerve denervation muscle atrophy model, we evaluated the effects of wild-type (MSPP) and mutant-type (MSPPD75A) of myostatin propeptide gene delivery, and observed changes in gene activation associated with the neuromuscular junction, muscle and nerve. Muscle mass and muscle fiber size was moderately increased in myostatin propeptide treated muscles (p<0.05). And enhancement of the gene expression of the muscle regulatory factors, neurite outgrowth factors (IGF-1, GAP43) and acetylcholine receptors was observed. Our results demonstrate that myostatin propeptide gene delivery, especially the mutant-type of MSPPD75A, attenuates muscle atrophy through myogenic regulatory factors and acetylcholine receptor regulation. Our data concluded that myostatin propeptide gene therapy may be a promising treatment for nerve denervation induced muscle atrophy. Copyright © 2016 Elsevier Inc. All rights reserved.

NP1EC Degradation Pathways Under Oxic and Microxic Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montgomery-Brown, John; Li, Yongmei; Ding, Wang-Hsien

2008-03-22

The degradation pathway of nonylphenol ethoxyacetic acid (NP1EC) and the conditions favoring CAP1EC formation were studied in aerobic microcosms constructed with soil from the Mesa soil aquifer treatment (SAT) facility (Arizona, USA) and pristine sediments from Coyote Creek (California, USA). In the Mesa microcosms, para-NP1EC was transformed to para-NP, before being rapidly transformed to nonyl alcohols via ipso-hydroxylation. While the formation of NP from APEMs has been observed by several researchers under anaerobic conditions, this is the first time the transient formation of NP from APEMs has been observed under aerobic conditions. Unlike the Mesa microcosms, large quantities of CAP1ECsmore » were observed in the Coyote Creek microcosms. Initially, CA8P1ECs were the dominant metabolites, but as biodegradation continued, CA6P1ECs became the dominant metabolites. Compared to the CA8P1ECs, the number of CA6P1ECs peaks observed was small (<6) even though their concentrations were high. This suggests that several CA8P1ECs are degraded to only a few CA6P1EC isomers (i.e., the degradation pathway converges) or that some CA6P1EC metabolites are significantly more recalcitrant than others. The different biodegradation pathways observed in the Mesa and Coyote Creek microcosms result from the limited availability of dissolved oxygen in the Coyote Creek microcosms. In both sets of microcosms, the ortho isomers were transformed more slowly than the para isomers and in the Coyote Creek microcosms several ortho-CAP1ECs were observed. In addition, several unknown metabolites were observed in the Coyote Creek microcosms that were not seen in the abiotic or Mesa microcosms; these metabolites appear to be CAP1EC metabolites, have a -CH2-C6H4- fragment, and contain one carboxylic acid. Nitro-nonylphenol was observed in the Mesa microcosms, however, further experimentation illustrated that it was the product of an abiotic reaction between nitrite and nonylphenol under acidic

Altered expression of BDNF, BDNF pro-peptide and their precursor proBDNF in brain and liver tissues from psychiatric disorders: rethinking the brain-liver axis.

PubMed

Yang, B; Ren, Q; Zhang, J-C; Chen, Q-X; Hashimoto, K

2017-05-16

Brain-derived neurotrophic factor (BDNF) has a role in the pathophysiology of psychiatric disorders. The precursor proBDNF is converted to mature BDNF and BDNF pro-peptide, the N-terminal fragment of proBDNF; however, the precise function of these proteins in psychiatric disorders is unknown. We sought to determine whether expression of these proteins is altered in the brain and peripheral tissues from patients with psychiatric disorders. We measured protein expression of proBDNF, mature BDNF and BDNF pro-peptide in the parietal cortex, cerebellum, liver and spleen from control, major depressive disorder (MDD), schizophrenia (SZ) and bipolar disorder (BD) groups. The levels of mature BDNF in the parietal cortex from MDD, SZ and BD groups were significantly lower than the control group, whereas the levels of BDNF pro-peptide in this area were significantly higher than controls. In contrast, the levels of proBDNF and BDNF pro-peptide in the cerebellum of MDD, SZ and BD groups were significantly lower than controls. Moreover, the levels of mature BDNF from the livers of MDD, SZ and BD groups were significantly higher than the control group. The levels of mature BDNF in the spleen did not differ among the four groups. Interestingly, there was a negative correlation between mature BDNF in the parietal cortex and mature BDNF in the liver in all the subjects. These findings suggest that abnormalities in the production of mature BDNF and BDNF pro-peptide in the brain and liver might have a role in the pathophysiology of psychiatric disorders, indicating a brain-liver axis in psychiatric disorders.

THE EFFECT OF THE {sup 14}N(p, {gamma}){sup 15}O REACTION ON THE BLUE LOOPS IN INTERMEDIATE-MASS STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halabi, Ghina M.; El Eid, Mounib F.; Champagne, Arthur

2012-12-10

We present stellar evolutionary sequences of stars in the mass range 5-12 M{sub Sun }, having solar-like initial composition. The stellar models are obtained using updated input physics, including recent rates of thermonuclear reactions. We investigate the effects of a modification of the {sup 14}N(p, {gamma}){sup 15}O reaction rate, as suggested by recent evaluations, on the formation and extension of the blue loops encountered during the evolution of the stars in the above mass range. We find that a reduced {sup 14}N(p, {gamma}){sup 15}O rate, as described in the text, has a striking impact on the physical conditions of burningmore » and mixing during shell hydrogen burning when the blue loops are formed. In particular, we find that the efficiency of shell hydrogen burning is crucial for the formation of an extended blue loop. We show that a significantly reduced {sup 14}N(p, {gamma}){sup 15}O rate affects severely the extension of the blue loops and the time spent by the star in the blue part of the Hertzsprung-Russell diagram in the mass range 5-7 M{sub Sun} if the treatment of convection is based on the Schwarzschild criterion only. In this case, envelope overshooting helps to restore well-extended blue loops as supported by the observations of the Cepheid stars. If core overshooting is included during the core hydrogen and core helium burning phases, the loop formation and its properties depend on how this overshooting is treated for a given stellar mass range, as well as on its efficiency.« less

The N-terminal Region of the Ubiquitin Regulatory X (UBX) Domain-containing Protein 1 (UBXD1) Modulates Interdomain Communication within the Valosin-containing Protein p97*

PubMed Central

Trusch, Franziska; Matena, Anja; Vuk, Maja; Koerver, Lisa; Knævelsrud, Helene; Freemont, Paul S.; Meyer, Hemmo; Bayer, Peter

2015-01-01

Valosin-containing protein/p97 is an ATP-driven protein segregase that cooperates with distinct protein cofactors to control various aspects of cellular homeostasis. Mutations at the interface between the regulatory N-domain and the first of two ATPase domains (D1 and D2) deregulate the ATPase activity and cause a multisystem degenerative disorder, inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia/amyotrophic lateral sclerosis. Intriguingly, the mutations affect only a subset of p97-mediated pathways correlating with unbalanced cofactor interactions and most prominently compromised binding of the ubiquitin regulatory X domain-containing protein 1 (UBXD1) cofactor during endolysosomal sorting of caveolin-1. However, how the mutations impinge on the p97-cofactor interplay is unclear so far. In cell-based endosomal localization studies, we identified a critical role of the N-terminal region of UBXD1 (UBXD1-N). Biophysical studies using NMR and CD spectroscopy revealed that UBXD1-N can be classified as intrinsically disordered. NMR titration experiments confirmed a valosin-containing protein/p97 interaction motif and identified a second binding site at helices 1 and 2 of UBXD1-N as binding interfaces for p97. In reverse titration experiments, we identified two distant epitopes on the p97 N-domain that include disease-associated residues and an additional interaction between UBXD1-N and the D1D2 barrel of p97 that was confirmed by fluorescence anisotropy. Functionally, binding of UBXD1-N to p97 led to a reduction of ATPase activity and partial protection from proteolysis. These findings indicate that UBXD1-N intercalates into the p97-ND1 interface, thereby modulating interdomain communication of p97 domains and its activity with relevance for disease pathogenesis. We propose that the polyvalent binding mode characterized for UBXD1-N is a more general principle that defines a subset of p97 cofactors. PMID:26475856

Annealing and anomalous high-energy electron irradiation effects in low-cost silicon N+P solar cells

NASA Technical Reports Server (NTRS)

Garlick, G. F. J.; Kachare, A. H.

1981-01-01

Silicon solar cells of N(+)P type were subjected to 1 MeV electron irradiation (up to 10 to the 16th electrons/sq cm) and then annealed at 450 C for 20 min or annealed with no electron irradiation. Electron irradiation resulted in a degradation of longer wavelength cell response, but produced a marked enhancement of response at shorter wavelengths with a peak change of 40% at 0.44 microns. Subsequent thermal anneal at 450 C reduced the long-wavelength degradation, but enhancement at shorter wavelengths persisted. Excitation at the shorter wavelengths was in the N(+)-diffused layer and in the junction region of the cell. Anneal of unirradiated cells produced shorter-wavelength enhancement with a similar peaking at 0.44 microns, but with a relative change of only 20%. More enhancement was produced in the longer wavelength region (up to 0.8 microns). These effects in the different cell regions are explained by a decrease in the interstitial oxygen-impurity complexes (deep recombination levels) and the formation of substantial oxygen-silicon vacancy centers (donors).

Nicotiana plumbaginifolia plants silenced for the ATP-binding cassette transporter gene NpPDR1 show increased susceptibility to a group of fungal and oomycete pathogens.

PubMed

Bultreys, Alain; Trombik, Tomasz; Drozak, Anna; Boutry, Marc

2009-09-01

SUMMARY The behaviour of Nicotiana plumbaginifolia plants silenced for the ATP-binding cassette transporter gene NpPDR1 was investigated in response to fungal and oomycete infections. The importance of NpPDR1 in plant defence was demonstrated for two organs in which NpPDR1 is constitutively expressed: the roots and the petal epidermis. The roots of the plantlets of two lines silenced for NpPDR1 expression were clearly more sensitive than those of controls to the fungal pathogens Botrytis cinerea, Fusarium oxysporum sp., F. oxysporum f. sp. nicotianae, F. oxysporum f. sp. melonis and Rhizoctonia solani, as well as to the oomycete pathogen Phytophthora nicotianae race 0. The Ph gene-linked resistance of N. plumbaginifolia to P. nicotianae race 0 was totally ineffective in NpPDR1-silenced lines. In addition, the petals of the NpPDR1-silenced lines were spotted 15%-20% more rapidly by B. cinerea than were the controls. The rapid induction (after 2-4 days) of NpPDR1 expression in N. plumbaginifolia and N. tabacum mature leaves in response to pathogen presence was demonstrated for the first time with fungi and one oomycete: R. solani, F. oxysporum and P. nicotianae. With B. cinerea, such rapid expression was not observed in healthy mature leaves. NpPDR1 expression was not observed during latent infections of B. cinerea in N. plumbaginifolia and N. tabacum, but was induced when conditions facilitated B. cinerea development in leaves, such as leaf ageing or an initial root infection. This work demonstrates the increased sensitivity of NpPDR1-silenced N. plumbaginifolia plants to all of the fungal and oomycete pathogens investigated.

Recovery of Electron/Proton Radiation-Induced Defects in n+p AlInGaP Solar Cell by Minority-Carrier Injection Annealing

NASA Technical Reports Server (NTRS)

Lee, H. S.; Yamaguchi, M.; Elkins-Daukes, N. J.; Khan, A.; Takamoto, T.; Imaizumi, M.; Ohshima, T.; Itoh, H.

2007-01-01

A high efficient In0.48Ga0.52P/In0.01Ga0.99As/Ge triple junction solar cell has been developed for application in space and terrestrial concentrator PV system [1-3]. Recently, a high conversion efficiency of 31.5% (AM1.5G) has been obtained in InGaP/(In)GaAs/Ge triple junction solar cell, and as a new top cell material of triple junction cells, (Al)InGaP [1] has been proposed to improve the open-circuit voltage (Voc) because it shows a higher Voc of 1.5V while maintaining the same short-circuit current (ISC) as a conventional InGaP top cell under AM1.5G conditions as seen in figure 1 (a). Moreover, the spectral response of 1.96eV AlInGaP cell with a thickness of 2.5..m shows a higher response in the long wavelength region, compared with that of 1.87eV InGaP cell with 0.6..m thickness, as shown in figure 1 (b). Its development will realize next generation multijunction (MJ) solar cells such as a lattice mismatched AlInGaP/InGaAs/Ge 3-junction and lattice matched AlInGaP/GaAs/InGaAsN/Ge 4-junction solar cells. Figure 2 shows the super high-efficiency MJ solar cell structures and wide band spectral response by MJ solar cells under AM1.5G conditions. For realizing high efficient MJ space solar cells, the higher radiation-resistance under the electron or proton irradiation is required. The irradiation studies for a conventional top cell InGaP have been widely done [4-6], but little irradiation work has been performed on AlInGaP solar cells. Recently, we made the first reports of 1 MeV electron or 30 keV proton irradiation effects on AlInGaP solar cells, and evaluated the defects generated by the irradiation [7,8]. The present study describes the recovery of 1 MeV electron / 30 keV proton irradiation-induced defects in n+p- AlInGaP solar cells by minority-carrier injection enhanced annealing or isochronal annealing. The origins of irradiation-induced defects observed by deep level transient spectroscopy (DLTS) measurements are discussed.

P ≠NP Millenium-Problem(MP) TRIVIAL Physics Proof Via NATURAL TRUMPS Artificial-``Intelligence'' Via: Euclid Geometry, Plato Forms, Aristotle Square-of-Opposition, Menger Dimension-Theory Connections!!! NO Computational-Complexity(CC)/ANYthing!!!: Geometry!!!

NASA Astrophysics Data System (ADS)

Clay, London; Menger, Karl; Rota, Gian-Carlo; Euclid, Alexandria; Siegel, Edward

P ≠NP MP proof is by computer-''science''/SEANCE(!!!)(CS) computational-''intelligence'' lingo jargonial-obfuscation(JO) NATURAL-Intelligence(NI) DISambiguation! CS P =(?) =NP MEANS (Deterministic)(PC) = (?) =(Non-D)(PC) i.e. D(P) =(?) = N(P). For inclusion(equality) vs. exclusion (inequality) irrelevant (P) simply cancels!!! (Equally any/all other CCs IF both sides identical). Crucial question left: (D) =(?) =(ND), i.e. D =(?) = N. Algorithmics[Sipser[Intro. Thy.Comp.(`97)-p.49Fig.1.15!!!

NMR assignments of the N-terminal domain of Nephila clavipes spidroin 1

PubMed Central

Parnham, Stuart; Gaines, William A.; Duggan, Brendan M.; Marcotte, William R.

2011-01-01

The building blocks of spider dragline silk are two fibrous proteins secreted from the major ampullate gland named spidroins 1 and 2 (MaSp1, MaSp2). These proteins consist of a large central domain composed of approximately 100 tandem copies of a 35–40 amino acid repeat sequence. Non-repetitive N and C-terminal domains, of which the C-terminal domain has been implicated to transition from soluble and insoluble states during spinning, flank the repetitive core. The N-terminal domain until recently has been largely unknown due to difficulties in cloning and expression. Here, we report nearly complete assignment for all 1H, 13C, and 15N resonances in the 14 kDa N-terminal domain of major ampullate spidroin 1 (MaSp1-N) of the golden orb-web spider Nephila clavipes. PMID:21152998

Increased expression of NF-AT3 and NF-AT4 in the atria correlates with procollagen I carboxyl terminal peptide and TGF-β1 levels in serum of patients with atrial fibrillation.

PubMed

Zhao, Fei; Zhang, ShiJiang; Chen, YiJiang; Gu, WeiDong; Ni, BuQing; Shao, YongFeng; Wu, YanHu; Qin, JianWei

2014-11-25

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. Unfortunately, the precise mechanisms and sensitive serum biomarkers of atrial remodeling in AF remain unclear. The aim of this study was to determine whether the expression of the transcription factors NF-AT3 and NF-AT4 correlate with atrial structural remodeling of atrial fibrillation and serum markers for collagen I and III synthesis. Right and left atrial specimens were obtained from 90 patients undergoing valve replacement surgery. The patients were divided into sinus rhythm (n = 30), paroxysmal atrial fibrillation (n = 30), and persistent atrial fibrillation (n = 30) groups. NF-AT3, NF-AT4, and collagen I and III mRNA and protein expression in atria were measured. We also tested the levels of the carboxyl-terminal peptide from pro-collagen I, the N-terminal type I procollagen propeptides, the N-terminal type III procollagen propeptides, and TGF-β1 in serum using an enzyme immunosorbent assay. NF-AT3 and NF-AT4 mRNA and protein expression were increased in the AF groups, especially in the left atrium. NF-AT3 and NF-AT4 expression in the right atrium was increased in the persistent atrial fibrillation group compared the sinus rhythm group with similar valvular disease. In patients with AF, the expression levels of nuclear NF-AT3 and NF-AT4 correlated with those of collagens I and III in the atria and with PICP and TGF-β1 in blood. These data support the hypothesis that nuclear NF-AT3 and NF-AT4 participates in atrial structural remodeling, and that PICP and TGF-β1 levels may be sensitive serum biomarkers to estimate atrial structural remodeling with atrial fibrillation.

Measurement of the np total cross section difference Δ σ L(np) at 1.39, 1.69, 1.89 and 1.99 GeV

NASA Astrophysics Data System (ADS)

Sharov, V. I.; Anischenko, N. G.; Antonenko, V. G.; Averichev, S. A.; Azhgirey, L. S.; Bartenev, V. D.; Bazhanov, N. A.; Belyaev, A. A.; Blinov, N. A.; Borisov, N. S.; Borzakov, S. B.; Borzunov, Yu T.; Bushuev, Yu P.; Chernenko, L. P.; Chernykh, E. V.; Chumakov, V. F.; Dolgii, S. A.; Fedorov, A. N.; Fimushkin, V. V.; Finger, M.; Finger, M.; Golovanov, L. B.; Gurevich, G. M.; Janata, A.; Kirillov, A. D.; Kolomiets, V. G.; Komogorov, E. V.; Kovalenko, A. D.; Kovalev, A. I.; Krasnov, V. A.; Krstonoshich, P.; Kuzmin, E. S.; Ladygin, V. P.; Lazarev, A. B.; Lehar, F.; de Lesquen, A.; Liburg, M. Yu; Livanov, A. N.; Lukhanin, A. A.; Maniakov, P. K.; Matafonov, V. N.; Matyushevsky, E. A.; Moroz, V. D.; Morozov, A. A.; Neganov, A. B.; Nikolaevsky, G. P.; Nomofilov, A. A.; Panteleev, Tz; Pilipenko, Yu K.; Pisarev, I. L.; Plis, Yu A.; Polunin, Yu P.; Prokofiev, A. N.; Prytkov, V. Yu; Rukoyatkin, P. A.; Schedrov, V. A.; Schevelev, O. N.; Shilov, S. N.; Shindin, R. A.; Slunečka, M.; Slunečková, V.; Starikov, A. Yu; Stoletov, G. D.; Strunov, L. N.; Svetov, A. L.; Usov, Yu A.; Vasiliev, T.; Volkov, V. I.; Vorobiev, E. I.; Yudin, I. P.; Zaitsev, I. V.; Zhdanov, A. A.; Zhmyrov, V. N.

2004-09-01

New accurate results of the neutron-proton spin-dependent total cross section difference Δσ_L(np) at the neutron beam kinetic energies 1.39, 1.69, 1.89 and 1.99 GeV are presented. Measurements were carried out in 2001 at the Synchrophasotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research. A quasi-monochromatic neutron beam was produced by break-up of extracted polarized deuterons. The deuteron (and hence neutron) polarization direction was flipped every accelerator burst. The vertical neutron polarization direction was rotated onto the neutron beam direction and longitudinally (L) polarized neutrons were transmitted through a large proton L-polarized target. The target polarization vector was inverted after 1-2 days of measurements. The data were recorded for four different combinations of the beam and target parallel and antiparallel polarization directions at each energy. A fast decrease of Δσ_L(np) with increasing energy above 1.1 GeV was confirmed. The structure in the Δσ_L(np) energy dependence around 1.8 GeV, first observed from our previous data, seems to be well pronounced. The new results are also compared with model predictions and with phase shift analysis fits. The Δσ_L quantities for isosinglet state I = 0, deduced from the measured Δσ_L(np) values and the known Δσ_L(pp) data, are also given. The results were completed by the measurements of unpolarized total cross sections σ_{0tot}(np) at 1.3, 1.4 and 1.5 GeV and σ_{0tot}(nC) at 1.4 and 1.5 GeV. These data were obtained using the same apparatus and high intensity unpolarized deuteron beams were extracted either from the Synchrophasotron, or from the Nuclotron.

Relationship between bone turnover and left ventricular function in primary hyperparathyroidism: The EPATH trial.

PubMed

Verheyen, Nicolas; Fahrleitner-Pammer, Astrid; Belyavskiy, Evgeny; Gruebler, Martin R; Dimai, Hans Peter; Amrein, Karin; Ablasser, Klemens; Martensen, Johann; Catena, Cristiana; Pieske-Kraigher, Elisabeth; Colantonio, Caterina; Voelkl, Jakob; Lang, Florian; Alesutan, Ioana; Meinitzer, Andreas; März, Winfried; Brussee, Helmut; Pieske, Burkert; Pilz, Stefan; Tomaschitz, Andreas

2017-01-01

Observational studies suggested a link between bone disease and left ventricular (LV) dysfunction that may be pronounced in hyperparathyroid conditions. We therefore aimed to test the hypothesis that circulating markers of bone turnover correlate with LV function in a cohort of patients with primary hyperparathyroidism (pHPT). Cross-sectional data of 155 subjects with pHPT were analyzed who participated in the "Eplerenone in Primary Hyperparathyroidism" (EPATH) Trial. Multivariate linear regression analyses with LV ejection fraction (LVEF, systolic function) or peak early transmitral filling velocity (e', diastolic function) as dependent variables and N-terminal propeptide of procollagen type 1 (P1NP), osteocalcin (OC), bone-specific alkaline phosphatase (BALP), or beta-crosslaps (CTX) as the respective independent variable were performed. Analyses were additionally adjusted for plasma parathyroid hormone, plasma calcium, age, sex, HbA1c, body mass index, mean 24-hours systolic blood pressure, smoking status, estimated glomerular filtration rate, antihypertensive treatment, osteoporosis treatment, 25-hydroxy vitamin D and N-terminal pro-brain B-type natriuretic peptide. Independent relationships were observed between P1NP and LVEF (adjusted β-coefficient = 0.201, P = 0.035) and e' (β = 0.188, P = 0.042), respectively. OC (β = 0.192, P = 0.039) and BALP (β = 0.198, P = 0.030) were each independently related with e'. CTX showed no correlations with LVEF or e'. In conclusion, high bone formation markers were independently and paradoxically related with better LV diastolic and, partly, better systolic function, in the setting of pHPT. Potentially cardio-protective properties of stimulated bone formation in the context of hyperparathyroidism should be explored in future studies.

The N-terminal cysteine pair of yeast sulfhydryl oxidase Erv1p is essential for in vivo activity and interacts with the primary redox centre.

PubMed

Hofhaus, Götz; Lee, Jeung-Eun; Tews, Ivo; Rosenberg, Beate; Lisowsky, Thomas

2003-04-01

Yeast Erv1p is a ubiquitous FAD-dependent sulfhydryl oxidase, located in the intermembrane space of mitochondria. The dimeric enzyme is essential for survival of the cell. Besides the redox-active CXXC motif close to the FAD, Erv1p harbours two additional cysteine pairs. Site-directed mutagenesis has identified all three cysteine pairs as essential for normal function. The C-terminal cysteine pair is of structural importance as it contributes to the correct arrangement of the FAD-binding fold. Variations in dimer formation and unique colour changes of mutant proteins argue in favour of an interaction between the N-terminal cysteine pair with the redox centre of the partner monomer.

The Aquaporin Splice Variant NbXIP1;1α Is Permeable to Boric Acid and Is Phosphorylated in the N-terminal Domain

PubMed Central

Ampah-Korsah, Henry; Anderberg, Hanna I.; Engfors, Angelica; Kirscht, Andreas; Norden, Kristina; Kjellstrom, Sven; Kjellbom, Per; Johanson, Urban

2016-01-01

Aquaporins (AQPs) are membrane channel proteins that transport water and uncharged solutes across different membranes in organisms in all kingdoms of life. In plants, the AQPs can be divided into seven different subfamilies and five of these are present in higher plants. The most recently characterized of these subfamilies is the XIP subfamily, which is found in most dicots but not in monocots. In this article, we present data on two different splice variants (α and β) of NbXIP1;1 from Nicotiana benthamiana. We describe the heterologous expression of NbXIP1;1α and β in the yeast Pichia pastoris, the subcellular localization of the protein in this system and the purification of the NbXIP1;1α protein. Furthermore, we investigated the functionality and the substrate specificity of the protein by stopped-flow spectrometry in P. pastoris spheroplasts and with the protein reconstituted in proteoliposomes. The phosphorylation status of the protein and localization of the phosphorylated amino acids were verified by mass spectrometry. Our results show that NbXIP1;1α is located in the plasma membrane when expressed in P. pastoris, that it is not permeable to water but to boric acid and that the protein is phosphorylated at several amino acids in the N-terminal cytoplasmic domain of the protein. A growth assay showed that the yeast cells expressing the N-terminally His-tagged NbXIP1;1α were more sensitive to boric acid as compared to the cells expressing the C-terminally His-tagged isoform. This might suggest that the N-terminal His-tag functionally mimics the phosphorylation of the N-terminal domain and that the N-terminal domain is involved in gating of the channel. PMID:27379142

High temperature annealing of minority carrier traps in irradiated MOCVD n(+)p InP solar cell junctions

NASA Technical Reports Server (NTRS)

Messenger, S. R.; Walters, R. J.; Summers, G. P.

1993-01-01

Deep level transient spectroscopy was used to monitor thermal annealing of trapping centers in electron irradiated n(+)p InP junctions grown by metalorganic chemical vapor deposition, at temperatures ranging from 500 up to 650K. Special emphasis is given to the behavior of the minority carrier (electron) traps EA (0.24 eV), EC (0.12 eV), and ED (0.31 eV) which have received considerably less attention than the majority carrier (hole) traps H3, H4, and H5, although this work does extend the annealing behavior of the hole traps to higher temperatures than previously reported. It is found that H5 begins to anneal above 500K and is completely removed by 630K. The electron traps begin to anneal above 540K and are reduced to about half intensity by 630K. Although they each have slightly different annealing temperatures, EA, EC, and ED are all removed by 650K. A new hole trap called H3'(0.33 eV) grows as the other traps anneal and is the only trap remaining at 650K. This annealing behavior is much different than that reported for diffused junctions.

Serum level of interleukin-6 (IL-6) and N-terminal propeptide of procollagen type I (PINP) in patients with liver diseases.

PubMed

Gudowska-Sawczuk, Monika; Wrona, Alicja; Gruszewska, Ewa; Cylwik, Bogdan; Panasiuk, Anatol; Flisiak, Robert; Chrostek, Lech

The aim of this study was to evaluate the concentration of interleukin-6 and N-terminal propeptide of procollagen type I and their relationship in liver diseases of different etiologies. Serum samples were obtained from 30 healthy volunteers and patients suffering from alcoholic cirrhosis (AC) - 31, non-alcoholic cirrhosis (NAC) - 28 and toxic hepatitis (HT) - 23 patients. Cirrhotic patients were classified according to Child-Pugh score. IL-6 and PINP concentrations were determined according to the electrochemiluminescence immunoassay. The mean serum IL-6 concentration was significantly higher in AC (mean ± SD:21.52 ± 15.01 pg/mL), NAC (20.07 ± 32.12 pg/mL) and HT (15.14 ± 17.18 pg/mL) when compared to the control group (C) (1.67 ± 0.42 pg/mL) (Mann-Whitney U test: p < .001 for all comparisons). The mean serum PINP concentration was significantly higher only in patients with AC (104.32 ± 54.50 ng/mL) in comparison with the control group (54.70 ± 19.83 ng/mL; p < .001). The mean values of IL-6 and PINP significantly differed between liver diseases (ANOVA rank Kruskal-Wallis test: p = .020 and p < .001, respectively). Accordingly, the serum levels of IL-6 and PINP were significantly higher in patients with AC than that in NAC (p < .001 and p = .022, respectively). IL-6 and PINP concentrations appeared to vary depending on the severity of liver damage (p < .001 for both). The concentrations of IL-6 and PINP were significantly higher in class C (31.88 ± 21.51 pg/mL; 132.73 ± 65.63 ng/mL, respectively) than that in class A (6.12 ± 9.00 pg/mL; 57.32 ± 28.85 ng/mL, respectively) (p < .001 for both). There were also significant differences in IL-6 concentrations between Child-Pugh class B (27.88 ± 24.45 pg/mL) and class A (6.12 ± 9.00 pg/mL; p < .001). We conclude that serum concentrations of IL-6 and PINP change in liver diseases, and those changes

Cross section measurement of 14N(p ,γ )15O in the CNO cycle

NASA Astrophysics Data System (ADS)

Li, Q.; Görres, J.; deBoer, R. J.; Imbriani, G.; Best, A.; Kontos, A.; LeBlanc, P. J.; Uberseder, E.; Wiescher, M.

2016-05-01

Background: The CNO cycle is the main energy source in stars more massive than our sun; it defines the energy production and the cycle time that lead to the lifetime of massive stars, and it is an important tool for the determination of the age of globular clusters. In our sun about 1.6% of the total solar neutrino flux comes from the CNO cycle. The largest uncertainty in the prediction of this CNO flux from the standard solar model comes from the uncertainty in the 14N(p ,γ )15O reaction rate; thus, the determination of the cross section at astrophysical temperatures is of great interest. Purpose: The total cross section of the 14N(p ,γ )15O reaction has large contributions from the transitions to the Ex=6.79 MeV excited state and the ground state of 15O. The Ex=6.79 MeV transition is dominated by radiative direct capture, while the ground state is a complex mixture of direct and resonance capture components and the interferences between them. Recent studies have concentrated on cross-section measurements at very low energies, but broad resonances at higher energy may also play a role. A single measurement has been made that covers a broad higher-energy range but it has large uncertainties stemming from uncorrected summing effects. Furthermore, the extrapolations of the cross section vary significantly depending on the data sets considered. Thus, new direct measurements have been made to improve the previous high-energy studies and to better constrain the extrapolation. Methods: Measurements were performed at the low-energy accelerator facilities of the nuclear science laboratory at the University of Notre Dame. The cross section was measured over the proton energy range from Ep=0.7 to 3.6 MeV for both the ground state and the Ex=6.79 MeV transitions at θlab=0∘ , 45∘, 90∘, 135∘, and 150∘. Both TiN and implanted-14N targets were utilized. γ rays were detected by using an array of high-purity germanium detectors. Results: The excitation function as

Adenosine-derived doped carbon dots: From an insight into effect of N/P co-doping on emission to highly sensitive picric acid sensing.

PubMed

Li, Na; Liu, Shi Gang; Fan, Yu Zhu; Ju, Yan Jun; Xiao, Na; Luo, Hong Qun; Li, Nian Bing

2018-07-12

The various synthetic routes of carbon dots (C-dots) feature a considerable step toward their potential use in chemical sensors and biotechnology. Herein, by coupling phosphorus and nitrogen element introduction, the adenosine-derived N/P co-doped C-dots with fluorescence enhancement were achieved. By separately employing adenosine, adenosine monophosphate, adenosine diphosphate, and adenosine-5'-triphosphate as precursors, the effect of N/P co-doping on the fluorescence emission is discussed in detail. The formed C-dots with adenosine monophosphate exhibited strong blue fluorescence with a high quantum yield of 33.81%. Then the C-dots were employed as a fluorescent probe and utilized to develop a fast, sensitive, and selective picric acid sensor. The fluorescence of C-dots can be quenched by picric acid immediately, giving rise to a picric acid determination down to 30 nM. The possible mechanism of fluorescence quenching was discussed, which was proved to be inner filter effect and static quenching. Moreover, this method has the potential to detect picric acid in environmental water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Atypical Chemokine Receptor 1 polymorphism cannot be used as an indicator of liver fibrosis progression in Hepatitis C virus positive patients

PubMed Central

Shao, Lin-Nan; Zhang, Shu-Ting; Zhou, Shi-Hang; Yu, Wei-Jian; Liu, Ming

2017-01-01

Background & Objective: Atypical chemokine receptor 1(ACKR1) represents an atypical chemokine receptor that can bind promiscuously to various chemokines. Chemokines play a crucial role to recruit leukocyte subsets migration through the endothelium and into liver against the virus during the progression of hepatitis C virus (HCV) infection. Most HCV positive patients can lead to liver fibrosis. Hyaluronic acid (HA), laminin (LN), collagen IV(C-IV) and amino-terminal pro-peptide of Type-III pro-collagen (PIII NP) are indices of the extent of liver fibrosis. The aim of this study was to investigate the association between ACKR1 polymorphism and liver fibrosis with these four serum liver markers in HCV positive patients. Methods: From April 2015 to December 2015, a total of 210 patients (109 males and 101 females) with chronic HCV infection at Dalian Infectious Hospital were recruited to participate in this study. ACKR1 genotyping was using TaqMan probes method. HA, LN, C-IV and PIII NP were detected by using diagnostic kits. Results: We compared serum levels of HA, LN, C-IV and PIII NP between FY*A/FY*A and FY*A/FY*B patients and the differences were not significant (P=0.905, P=0.298, P=0.880 and P=0.470, respectively). Conclusions: This study has attempted to elucidate the role of ACKR1 polymorphism in liver fibrosis progression of HCV infection, our results demonstrated that ACKR1 polymorphism is not directly associated with the fibrogenesis in HCV positive patients. PMID:29142552

Amino-terminal propeptide of C-type natriuretic peptide and linear growth in children: effects of puberty, testosterone, and growth hormone.

PubMed

Olney, Robert C; Prickett, Timothy C R; Yandle, Timothy G; Espiner, Eric A; Han, Joan C; Mauras, Nelly

2007-11-01

C-type natriuretic peptide (CNP), a paracrine factor of the growth plate, plays a key role in stimulating bone growth. The amino-terminal propeptide of CNP (NTproCNP) is produced in equimolar amounts with CNP and is measurable in plasma, providing a potential biomarker for growth plate activity and, hence, linear growth. We explored the effects of puberty, testosterone, and GH treatment on NTproCNP levels in normal and short-statured children. This was a retrospective analysis of samples obtained during previous studies. The study was conducted at a pediatric clinical research center. Children with short stature due to GH deficiency, idiopathic short stature (ISS), or constitutional delay of growth and maturation (CDGM) were studied (n = 37). A cohort of normal-statured adolescent boys was also studied (n = 23). Children with GH deficiency and ISS were studied before and during testosterone and/or GH treatment. Boys with CDGM and healthy controls were studied once. The main outcomes were NTproCNP levels before and during growth-promoting therapy and during pubertal growth. Children with short stature due to GH deficiency, ISS, or CDGM had comparable baseline levels of NTproCNP, and levels increased markedly in response to GH or testosterone treatment. In boys with CDGM, levels were comparable with height-matched controls but were less than those from age-matched controls. In healthy boys, NTproCNP appears to peak with the pubertal growth spurt. NTproCNP levels increase during growth-promoting therapy and are increased during puberty in boys. This novel biomarker of growth may have clinical utility in the evaluation of children with short stature and for monitoring growth-promoting therapy.

A Mediterranean Diet Enriched with Olive Oil Is Associated with Higher Serum Total Osteocalcin Levels in Elderly Men at High Cardiovascular Risk

PubMed Central

Moreno-Navarrete, José Maria; Ricart, Wifredo; Ros, Emilio; Estruch, Ramon; Salas-Salvadó, Jordi

2012-01-01

Background: The intake of olive oil has been related to the prevention of osteoporosis in experimental and in in vitro models. Very few prospective studies have evaluated the effects of olive oil intake on circulating osteocalcin (OC) in humans. Objective: The objective of the study was to examine the longitudinal effects of a low-fat control diet (n = 34), a Mediterranean diet enriched with nuts (MedDiet+nuts, n = 51), or a Mediterranean diet enriched with virgin olive oil (MedDiet+VOO, n = 42) on circulating forms of OC and bone formation markers in elderly men at high cardiovascular risk. Design: Longitudinal associations between baseline and follow-up (2 yr) measurements of total OC, undercarboxylated osteocalcin, C-telopeptide of type I collagen, and procollagen I N-terminal propeptide (P1NP) concentrations were examined in 127 elderly men randomized to three healthy dietary interventions. Results: Baseline characteristics (age, body mass index, waist circumference, lipid profile, fasting insulin levels, and bone formation and resorption markers) were similar in all intervention groups. The total osteocalcin concentration increased robustly in the MedDiet+VOO group (P = 0.007) in parallel to increased P1NP levels (P = 0.01) and homeostasis model assessment-β-cell function (P = 0.01) but not in subjects on the MedDiet+nuts (P = 0.32) or after the control diet (P = 0.74). Interestingly, the consumption of olives was associated positively with both baseline total osteocalcin (r = 0.23, P = 0.02) and the 2-yr osteocalcin concentrations (r = 0.21, P = 0.04) in the total cohort. Conclusions: Consumption of a Mediterranean diet enriched with virgin olive oil for 2 years is associated with increased serum osteocalcin and P1NP concentrations, suggesting protective effects on bone. PMID:22855341

Four residues of propeptide are essential for precursor folding of nattokinase.

PubMed

Jia, Yan; Cao, Xinhua; Deng, Yu; Bao, Wei; Tang, Changyan; Ding, Hanjing; Zheng, Zhongliang; Zou, Guolin

2014-11-01

Subtilisin propeptide functions as an intramolecular chaperone that guides precursor folding. Nattokinase, a member of subtilisin family, is synthesized as a precursor consisting of a signal peptide, a propeptide, and a subtilisin domain, and the mechanism of its folding remains to be understood. In this study, the essential residues of nattokinase propeptide which contribute to precursor folding were determined. Deletion analysis showed that the conserved regions in propeptide were important for precursor folding. Single-site and multi-site mutagenesis studies confirmed the role of Tyr10, Gly13, Gly34, and Gly35. During stage (i) and (ii) of precursor folding, Tyr10 and Gly13 would form the part of interface with subtilisin domain. While Gly34 and Gly35 connected with an α-helix that would stabilize the structure of propeptide. The quadruple Ala mutation, Y10A/G13A/G34A/G35A, resulted in a loss of the chaperone function for the propeptide. This work showed the essential residues of propeptide for precursor folding via secondary structure and kinetic parameter analyses. © The Author 2014. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

Enhanced conversion efficiency in wide-bandgap GaNP solar cells

DOE PAGES

Sukrittanon, Supanee; Liu, Ren; Ro, Yun Goo; ...

2015-10-12

In this study, we demonstrate –2.05 eV dilute nitride GaNP solar cells on GaP substrates for potential use as the top junction in dual-junction integrated cells on Si. By adding a small amount of N into indirect-bandgap GaP, GaNP has several extremely important attributes: a direct-bandgap that is also tunable, and easily attained lattice-match with Si. Our best GaNP solar cell ([N] –1.8%, E g –2.05 eV) achieves an efficiency of 7.9%, even in the absence of a window layer. This GaNP solar cell's efficiency is 3× higher than the most efficient GaP solar cell to date and higher thanmore » other solar cells with similar direct bandgap (InGaP, GaAsP). Through a systematic study of the structural, electrical, and optical properties of the device, efficient broadband optical absorption and enhanced solar cell performance are demonstrated.« less

Interruption or deferral of antiretroviral therapy reduces markers of bone turnover compared with continuous therapy: the SMART Body Composition Substudy

PubMed Central

Hoy, Jennifer; Grund, Birgit; Roediger, Mollie; Ensrud, Kristine E.; Brar, Indira; Colebunders, Robert; De Castro, Nathalie; Johnson, Margaret; Sharma, Anjali; Carr, Andrew

2013-01-01

Bone mineral density (BMD) declines significantly in HIV patients on antiretroviral therapy (ART). We compared the effects of intermittent versus continuous ART on markers of bone turnover in the Body Composition substudy of the Strategies for Management of AntiRetroviral Therapy (SMART) trial and determined whether early changes in markers predicted subsequent change in BMD. For 202 participants (median age 44 years, 17% female, 74% on ART) randomised to continuous or intermittent ART, plasma markers of inflammation and bone turnover were evaluated at baseline, months 4 and 12; BMD at the spine (dual X-ray absorptiometry [DXA] and computed tomography) and hip (DXA) was evaluated annually. Compared to the continuous ART group, mean bone-specific alkaline phosphatase (bALP), osteocalcin, procollagen type 1 N-terminal propeptide (P1NP), N-terminal cross-linking telopeptide of type 1 collagen (NTX), and C-terminal cross-linking telopeptide of type 1 collagen (βCTX) decreased significantly in the intermittent ART group, whereas RANKL and the RANKL:osteoprotegerin (OPG) ratio increased (all p≤0.002 at month 4 and month 12). Increases in bALP, osteocalcin, P1NP, NTX, and βCTX at month 4 predicted decrease in hip BMD at month 12, while increases in RANKL and the RANKL:OPG ratio at month 4 predicted increase in hip and spine BMD at month 12. This study has shown that compared with continuous ART, interruption of ART results in a reduction in markers of bone turnover and increase in BMD at hip and spine, and that early changes in markers of bone turnover predict BMD changes at 12 months. PMID:23299909

Effect of MSTN propeptide protein on the growth and development of Altay lamb muscle.

PubMed

Du, W; Zhang, Y; Yang, J Z; Li, H B; Xia, J; Li, N; Zhang, J S; Yan, X M; Zhou, Z Y

2016-06-24

Prokaryotic expression technology was used to express maltose-binding protein binding myostatin (MSTN) propeptide fusion protein. Six disease-free Altay lambs were used in this study. The right leg gastrocnemii were injected with MSTN recombinant propeptide protein. The left leg gastrocnemii (the control group) were injected with the same dose of phosphate based saline. The lambs were fed during four months under the same conditions and then slaughtered. Gastrocnemius samples were hematoxylin-eosin stained and the size of the muscle fibers was measured. A real-time polymerase chain reaction (RT-PCR) showed that single gastrocnemius cells in the experimental group had an average area of 1163.01 µm(2), while it was 845.09 µm(2) in the control group (P < 0.05). This indicates that the MSTN propeptide biological agents had an inhibitory effect on MSTN. In order to reveal its mechanism, RT-PCR was conducted to detect the expression of the differentiation-associated genes MyoD, Myf5, Myogenin, p21, and Smad3. The results showed that, in the MSTN propeptide biological agent injected group, expression levels of MSTN, Smad3, and p21 were lower than the control group, while Myf5, MyoD, and Myogenin were higher compared to the control group. This indicates that, when expression of the MSTN gene was inhibited, muscle cell differentiation and growth can be promoted by Smad3 up-regulated expression of Myf5, MyoD, and Myogenin.

Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sukrittanon, Supanee; Liu, Ren; Pan, Janet L.

2016-08-07

We report the demonstration of dilute nitride heterostructure core/shell microwire solar cells utilizing the combination of top-down reactive-ion etching to create the cores (GaP) and molecular beam epitaxy to create the shells (GaNP). Systematic studies of cell performance over a series of microwire lengths, array periods, and microwire sidewall morphologies examined by transmission electron microscopy were conducted to shed light on performance-limiting factors and to optimize the cell efficiency. We show by microscopy and correlated external quantum efficiency characterization that the open circuit voltage is degraded primarily due to the presence of defects at the GaP/GaNP interface and in themore » GaNP shells, and is not limited by surface recombination. Compared to thin film solar cells in the same growth run, the microwire solar cells exhibit greater short circuit current but poorer open circuit voltage due to greater light absorption and number of defects in the microwire structure, respectively. The comprehensive understanding presented in this work suggests that performance benefits of dilute nitride microwire solar cells can be achieved by further tuning of the epitaxial quality of the underlying materials.« less

Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current

NASA Astrophysics Data System (ADS)

Sukrittanon, Supanee; Liu, Ren; Breeden, Michael C.; Pan, Janet L.; Jungjohann, K. L.; Tu, Charles W.; Dayeh, Shadi A.

2016-08-01

We report the demonstration of dilute nitride heterostructure core/shell microwire solar cells utilizing the combination of top-down reactive-ion etching to create the cores (GaP) and molecular beam epitaxy to create the shells (GaNP). Systematic studies of cell performance over a series of microwire lengths, array periods, and microwire sidewall morphologies examined by transmission electron microscopy were conducted to shed light on performance-limiting factors and to optimize the cell efficiency. We show by microscopy and correlated external quantum efficiency characterization that the open circuit voltage is degraded primarily due to the presence of defects at the GaP/GaNP interface and in the GaNP shells, and is not limited by surface recombination. Compared to thin film solar cells in the same growth run, the microwire solar cells exhibit greater short circuit current but poorer open circuit voltage due to greater light absorption and number of defects in the microwire structure, respectively. The comprehensive understanding presented in this work suggests that performance benefits of dilute nitride microwire solar cells can be achieved by further tuning of the epitaxial quality of the underlying materials.

Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current

DOE PAGES

Sukrittanon, Supanee; Liu, Ren; Breeden, Michael C.; ...

2016-08-07

Here, we report the demonstration of dilute nitride heterostructure core/shell microwire solar cells utilizing the combination of top-down reactive-ion etching to create the cores (GaP) and molecular beam epitaxy to create the shells (GaNP). Systematic studies of cell performance over a series of microwire lengths, array periods, and microwire sidewall morphologies examined by transmission electron microscopy were conducted to shed light on performance-limiting factors and to optimize the cell efficiency. We also show by microscopy and correlated external quantum efficiency characterization that the open circuit voltage is degraded primarily due to the presence of defects at the GaP/GaNP interface andmore » in the GaNP shells, and is not limited by surface recombination. Compared to thin film solar cells in the same growth run, the microwire solar cells exhibit greater short circuit current but poorer open circuit voltage due to greater light absorption and number of defects in the microwire structure, respectively. Finally, we present performance benefits of dilute nitride microwire solar cells and show that it can be achieved by further tuning of the epitaxial quality of the underlying materials.« less

Purification, crystallization and preliminary X-ray diffraction of the N-terminal calmodulin-like domain of the human mitochondrial ATP-Mg/P{sub i} carrier SCaMC1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qin, E-mail: yang@crystal.harvard.edu; Brüschweiler, Sven; Chou, James J., E-mail: yang@crystal.harvard.edu

2013-12-24

The N-terminal calmodulin-like domain of the human mitochondrial ATP-Mg/P{sub i} carrier SCaMC1 was crystallized in the presence of Ca{sup 2+}. X-ray diffraction data were collected to 2.9 Å resolution from crystals which belonged to space group P6{sub 2}22.

Propeptide big-endothelin, N-terminal-pro brain natriuretic peptide and mortality. The Ludwigshafen risk and cardiovascular health (LURIC) study.

PubMed

Gergei, Ingrid; Krämer, Bernhard K; Scharnagl, Hubert; Stojakovic, Tatjana; März, Winfried; Mondorf, Ulrich

The endothelin system (Big-ET-1) is a key regulator in cardiovascular (CV) disease and congestive heart failure (CHF). We have examined the incremental value of Big-ET-1 in predicting total and CV mortality next to the well-established CV risk marker N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP). Big-ET-1 and NT-proBNP were determined in 2829 participants referred for coronary angiography (follow-up 9.9 years). Big-ET-1 is an independent predictor of total, CV mortality and death due to CHF. The conjunct use of Big-ET-1 and NT-proBNP improves the risk stratification of patients with intermediate to high risk of CV death and CHF. Big-ET-1improves risk stratification in patients referred for coronary angiography.

Characterization of an Invertase with pH Tolerance and Truncation of Its N-Terminal to Shift Optimum Activity toward Neutral pH

PubMed Central

Wang, Zilong; Lu, Jian; Wei, Yutuo; Huang, Ribo

2013-01-01

Most invertases identified to date have optimal activity at acidic pH, and are intolerant to neutral or alkaline environments. Here, an acid invertase named uninv2 is described. Uninv2 contained 586 amino acids, with a 100 amino acids N-terminal domain, a catalytic domain and a C-terminal domain. With sucrose as the substrate, uninv2 activity was optimal at pH 4.5 and at 45°C. Removal of N-terminal domain of uninv2 has shifted the optimum pH to 6.0 while retaining its optimum temperaure at 45°C. Both uninv2 and the truncated enzyme retained highly stable at neutral pH at 37°C, and they were stable at their optimum pH at 4°C for as long as 30 days. These characteristics make them far superior to invertase from Saccharomyces cerevisiae, which is mostly used as industrial enzyme. PMID:23638032

Characterization of an invertase with pH tolerance and truncation of its N-terminal to shift optimum activity toward neutral pH.

PubMed

Du, Liqin; Pang, Hao; Wang, Zilong; Lu, Jian; Wei, Yutuo; Huang, Ribo

2013-01-01

Most invertases identified to date have optimal activity at acidic pH, and are intolerant to neutral or alkaline environments. Here, an acid invertase named uninv2 is described. Uninv2 contained 586 amino acids, with a 100 amino acids N-terminal domain, a catalytic domain and a C-terminal domain. With sucrose as the substrate, uninv2 activity was optimal at pH 4.5 and at 45°C. Removal of N-terminal domain of uninv2 has shifted the optimum pH to 6.0 while retaining its optimum temperaure at 45°C. Both uninv2 and the truncated enzyme retained highly stable at neutral pH at 37°C, and they were stable at their optimum pH at 4°C for as long as 30 days. These characteristics make them far superior to invertase from Saccharomyces cerevisiae, which is mostly used as industrial enzyme.

Understanding and Interpreting Japanese NP1 "wa" NP2 "da" Sentences: Mechanism and Contextual Factors

ERIC Educational Resources Information Center

Yoshida, Megumi

2013-01-01

This dissertation investigates the contextual factors that affect the understanding and interpretation of one Japanese topicalized construction, NP[subscript 1] wa NP[subscript 2] da sentences, by native speakers of Japanese. The construction allows two possibilities in the relation between the NP[subscript 1] and the NP[subscript 2]. When the two…

A cathepsin F-like peptidase involved in barley grain protein mobilization, HvPap-1, is modulated by its own propeptide and by cystatins

PubMed Central

Diaz, Isabel

2012-01-01

Among the C1A cysteine proteases, the plant cathepsin F-like group has been poorly studied. This paper describes the molecular and functional characterization of the HvPap-1 cathepsin F-like protein from barley. This peptidase is N-glycosylated and has to be processed to become active by its own propeptide being an important modulator of the peptidase activity. The expression pattern of its mRNA and protein suggest that it is involved in different proteolytic processes in the barley plant. HvPap-1 peptidase has been purified in Escherichia coli and the recombinant protein is able to degrade different substrates, including barley grain proteins (hordeins, albumins, and globulins) stored in the barley endosperm. It has been localized in protein bodies and vesicles of the embryo and it is induced in aleurones by gibberellin treatment. These three features support the implication of HvPap-1 in storage protein mobilization during grain germination. In addition, a complex regulation exerted by the barley cystatins, which are cysteine protease inhibitors, and by its own propeptide, is also described PMID:22791822

The N-Terminal Domain of the Flo1 Flocculation Protein from Saccharomyces cerevisiae Binds Specifically to Mannose Carbohydrates ▿

PubMed Central

Goossens, Katty V. Y.; Stassen, Catherine; Stals, Ingeborg; Donohue, Dagmara S.; Devreese, Bart; De Greve, Henri; Willaert, Ronnie G.

2011-01-01

Saccharomyces cerevisiae cells possess a remarkable capacity to adhere to other yeast cells, which is called flocculation. Flocculation is defined as the phenomenon wherein yeast cells adhere in clumps and sediment rapidly from the medium in which they are suspended. These cell-cell interactions are mediated by a class of specific cell wall proteins, called flocculins, that stick out of the cell walls of flocculent cells. The N-terminal part of the three-domain protein is responsible for carbohydrate binding. We studied the N-terminal domain of the Flo1 protein (N-Flo1p), which is the most important flocculin responsible for flocculation of yeast cells. It was shown that this domain is both O and N glycosylated and is structurally composed mainly of β-sheets. The binding of N-Flo1p to d-mannose, α-methyl-d-mannoside, various dimannoses, and mannan confirmed that the N-terminal domain of Flo1p is indeed responsible for the sugar-binding activity of the protein. Moreover, fluorescence spectroscopy data suggest that N-Flo1p contains two mannose carbohydrate binding sites with different affinities. The carbohydrate dissociation constants show that the affinity of N-Flo1p for mono- and dimannoses is in the millimolar range for the binding site with low affinity and in the micromolar range for the binding site with high affinity. The high-affinity binding site has a higher affinity for low-molecular-weight (low-MW) mannose carbohydrates and no affinity for mannan. However, mannan as well as low-MW mannose carbohydrates can bind to the low-affinity binding site. These results extend the cellular flocculation model on the molecular level. PMID:21076009

Sialogogic activity in the rat of peptides analogous to [Tyr8]-substance P in which substitutions have been made in the N-terminal amino acids.

PubMed

Higa, K; Gao, C; Motokawa, W; Abe, K

2001-04-01

In order to elucidate the regulatory roles for salivation of amino acids in positions 1-4 of the N-terminal region of [Tyr8]-substance P (SP), the structure-sialogogic activity correlations of various synthetic octa- to undecapeptides replaced in positions 1-4 of [Tyr8]-SP with each of 19 common amino acids, one by one, and with the same sequence of the C-terminal hepatapeptide as that of [Tyr8]-SP, were studied in the submandibular glands of rats after intraperitoneal injection. Each of 19 octa-, nona-, deca- and undecapeptides with replaced amino acids and a penta- to decapeptide with the progressive elimination of the N-terminal portion were newly synthesized by the multipin peptide method. All octa- to undecapeptides replaced with each of 19 common amino acids in positions 1-4 had sialogogic activities. In 19 octa- and decapeptides in which P4 and P2 had been replaced, four and three replacements, respectively, had significantly increased secretory activities. In contrast, in 19 nonapeptides in which K3 had been replaced, none had significantly increased secretory activities. Furthermore, in 19 undecapeptides in which R1 had been replaced, most replacements had significantly increased or equipotent activities for fluid secretion. It is concluded that amino acids in the N-terminal region of various tachykinins may not need to be strictly conserved and that amino acid residues in the N-terminal portion, R1 in particular and P2, may strongly inhibit secretory activity.

Pump-probe photoelectron velocity-map imaging of autoionizing singly excited 4s{sup 1}4p{sup 6}np{sup 1}(n=7,8) and doubly excited 4s{sup 2}4p{sup 4}5s{sup 1}6p{sup 1} resonances in atomic krypton

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doughty, Benjamin; Haber, Louis H.; Leone, Stephen R.

2011-10-15

Pump-probe photoelectron velocity-map imaging, using 27-eV high-harmonic excitation and 786-nm ionization, is used to resolve overlapping autoionizing resonances in atomic krypton, obtaining two-photon photoelectron angular distributions (PADs) for singly and doubly excited states. Two features in the photoelectron spectrum are assigned to singly excited 4s{sup 1}4p{sup 6}np{sup 1} (n = 7,8) configurations and four features provide information about double excitation configurations. The anisotropy parameters for the singly excited 7p configuration are measured to be {beta}{sub 2} = 1.61 {+-} 0.06 and {beta}{sub 4} = 1.54 {+-} 0.16 while the 8p configuration gives {beta}{sub 2} = 1.23 {+-} 0.19 and {beta}{submore » 4} = 0.60 {+-} 0.15. These anisotropies most likely represent the sum of overlapping PADs from states of singlet and triplet spin multiplicities. Of the four bands corresponding to ionization of doubly excited states, two are assigned to 4s{sup 2}4p{sup 4}5s{sup 1}6p{sup 1} configurations that are probed to different J-split ion states. The two remaining doubly excited states are attributed to a previously observed, but unassigned, resonance in the vacuum-ultraviolet photoabsorption spectrum. The PADs from each of the double excitation states are also influenced by overlap from neighboring states that are not completely spectrally resolved. The anisotropies of the observed double excitation states are reported, anticipating future theoretical and experimental work to separate the overlapping PADs into the state resolved PADs. The results can be used to test theories of excited state ionization.« less

Intraspecific N and P stoichiometry of Phragmites australis: geographic patterns and variation among climatic regions.

PubMed

Hu, Yu-Kun; Zhang, Ya-Lin; Liu, Guo-Fang; Pan, Xu; Yang, Xuejun; Li, Wen-Bing; Dai, Wen-Hong; Tang, Shuang-Li; Xiao, Tao; Chen, Ling-Yun; Xiong, Wei; Song, Yao-Bin; Dong, Ming

2017-02-24

Geographic patterns in leaf stoichiometry reflect plant adaptations to environments. Leaf stoichiometry variations along environmental gradients have been extensively studied among terrestrial plants, but little has been known about intraspecific leaf stoichiometry, especially for wetland plants. Here we analyzed the dataset of leaf N and P of a cosmopolitan wetland species, Phragmites australis, and environmental (geographic, climate and soil) variables from literature and field investigation in natural wetlands distributed in three climatic regions (subtropical, temperate and highland) across China. We found no clear geographic patterns in leaf nutrients of P. australis across China, except for leaf N:P ratio increasing with altitude. Leaf N and N:P decreased with mean annual temperature (MAT), and leaf N and P were closely related to soil pH, C:N ratio and available P. Redundancy analysis showed that climate and soil variables explained 62.1% of total variation in leaf N, P and N:P. Furthermore, leaf N in temperate region and leaf P in subtropical region increased with soil available P, while leaf N:P in subtropical region decreased with soil pH. These patterns in P. australis different from terrestrial plants might imply that changes in climate and soil properties can exert divergent effects on wetland and terrestrial ecosystems.

Vitamin D and its relationship with markers of bone metabolism in healthy Asian women.

PubMed

Tan, Karen M L; Saw, Sharon; Sethi, Sunil K

2013-07-01

In this study, we aimed to determine the normal ranges of 25-hydroxy-vitamin D(3) (25-OHD(3)), parathyroid hormone (PTH), and the markers of bone turnover, procollagen type 1 N propeptide (P1NP) and C-terminal cross-linked telopeptide of type 1 collagen (CTX), in normal healthy women in Singapore, and to explore the relationship between vitamin D, PTH, and these markers of bone turnover in the women. One hundred and ninety-seven healthy women, aged 25 to 60, were selected from a hospital staff health screening program; 68% were Chinese, 18% Malay, and 14% Indian. P1NP, CTX, and 25-OHD(3) were measured using the Roche Cobas® electrochemiluminescence immunoassay. Serum PTH was measured using the Siemens ADVIA Centaur® immunoassay. Sixty-five percent had 25-OHD(3) concentrations <50 nmol/l. Vitamin D insufficiency (25-OHD(3) < 50 nmol/l) was more prevalent in Malays (89%) and Indians (82%) compared to Chinese (56%). There was no correlation between vitamin D and age. PTH positively correlated with age, and Malays and Indians had higher PTH concentrations than Chinese. There was an inverse correlation between PTH and 25-OHD(3), but no threshold of 25-OHD(3) concentrations at which PTH plateaued. The bone turnover markers P1NP and CTX inversely correlated with age but were not different between ethnic groups. CTX and P1NP exhibited good correlation, however, there was no significant correlation between 25-OHD(3) or PTH concentrations and the bone turnover markers P1NP and CTX. Healthy women in Singapore have a high prevalence of vitamin D insufficiency. Vitamin D insufficiency was more prevalent in Malays and Indians compared to Chinese. © 2013 Wiley Periodicals, Inc.

Mechanistic insights into PEPT1-mediated transport of a novel antiepileptic, NP-647.

PubMed

Khomane, Kailas S; Nandekar, Prajwal P; Wahlang, Banrida; Bagul, Pravin; Shaikh, Naeem; Pawar, Yogesh B; Meena, Chhuttan Lal; Sangamwar, Abhay T; Jain, Rahul; Tikoo, K; Bansal, Arvind K

2012-09-04

The present study, in general, is aimed to uncover the properties of the transport mechanism or mechanisms responsible for the uptake of NP-647 into Caco-2 cells and, in particular, to understand whether it is a substrate for the intestinal oligopeptide transporter, PEPT1 (SLC15A1). NP-647 showed a carrier-mediated, saturable transport with Michaelis-Menten parameters K(m) = 1.2 mM and V(max) = 2.2 μM/min. The effect of pH, sodium ion (Na(+)), glycylsarcosine and amoxicillin (substrates of PEPT1), and sodium azide (Na(+)/K(+)-ATPase inhibitor) on the flux rate of NP-647 was determined. Molecular docking and molecular dynamics simulation studies were carried out to investigate molecular interactions of NP-647 with transporter using homology model of human PEPT1. The permeability coefficient (P(appCaco-2)) of NP-647 (32.5 × 10(-6) cm/s) was found to be four times higher than that of TRH. Results indicate that NP-647 is transported into Caco-2 cells by means of a carrier-mediated, proton-dependent mechanism that is inhibited by Gly-Sar and amoxicillin. In turn, NP-647 also inhibits the uptake of Gly-Sar into Caco-2 cells and, together, this evidence suggests that PEPT1 is involved in the process. Docking and molecular dynamics simulation studies indicate high affinity of NP-647 toward PEPT1 binding site as compared to TRH. High permeability of NP-647 over TRH is attributed to its increased hydrophobicity which increases its affinity toward PEPT1 by interacting with the hydrophobic pocket of the transporter through hydrophobic forces.

The Novel Preparation of P-N Junction Mesa Diodes by Silicon-Wafer Direct Bonding (SDB)

NASA Astrophysics Data System (ADS)

Yeh, Ching-Fa; Hwangleu, Shyang

1992-05-01

The key processes of silicon-wafer direct bonding (SDB), including hydrophilic surface formation and optimal two-step heat treatment, have been developed However, H2SO4/H2O2 solution being a strong oxidized acid solution, native oxide is found to have grown on the wafer surface as soon as a wafer is treated in this solution. In the case of a wafer further treated in diluted HF solution after hydrophilic surface formation, it is shown that the wafer surface can not only be cleaned of its native oxide but also remains hydrophilic, and can provide excellent voidless bonding. The N+/P and N/P combination junction mesa diodes fabricated on the wafers prepared by these novel SDB technologies are examined. The ideality factor n of the N/P mesa diode is 2.4˜2.8 for the voltage range 0.2˜0.3 V; hence, the lowering of the ideality factor n is evidently achieved. As for the N+/P mesa diode, the ideality factor n shows a value of 1.10˜1.30 for the voltage range 0.2˜0.6 V; the low value of n is attributed to an autodoping phenomenon which has caused the junction interface to form in the P-silicon bulk. However, the fact that the sustaining voltage of the N/P mesa diode showed a value greater than 520 V reveals the effectiveness of our novel SDB processes.

Nuclear MxA proteins form a complex with influenza virus NP and inhibit the transcription of the engineered influenza virus genome

PubMed Central

Turan, Kadir; Mibayashi, Masaki; Sugiyama, Kenji; Saito, Shoko; Numajiri, Akiko; Nagata, Kyosuke

2004-01-01

Mx proteins belong to the dynamin superfamily of high molecular weight GTPases and interfere with multiplication of a wide variety of viruses. Earlier studies show that nuclear mouse Mx1 and human MxA designed to be localized in the nucleus inhibit the transcription step of the influenza virus genome. Here we set a transient influenza virus transcription system using luciferase as a reporter gene and cells expressing the three RNA polymerase subunits, PB1, PB2 and PA, and NP. We used this reporter assay system and nuclear-localized MxA proteins to get clues for elucidating the anti-influenza virus activity of MxA. Nuclear-localized VP16-MxA and MxA-TAg NLS strongly interfered with the influenza virus transcription. Over-expression of PB2 led to a slight resumption of the transcription inhibition by nuclear MxA, whereas over-expression of PB1 and PA did not affect the MxA activity. Of interest is that the inhibitory activity of the nuclear MxA was markedly neutralized by over-expression of NP. An NP devoid of its C-terminal region, but containing the N-terminal RNA binding domain, also neutralized the VP16-MxA activity in a dose-dependent manner, whereas an NP lacking the N-terminal region did not affect the VP16-MxA activity. Further, not only VP16-MxA but also the wild-type MxA was found to interact with NP in influenza virus-infected cells. This indicates that the nuclear MxA suppresses the influenza virus transcription by interacting with not only PB2 but also NP. PMID:14752052

Crystallized N-terminal domain of influenza virus matrix protein M1 and method of determining and using same

NASA Technical Reports Server (NTRS)

Luo, Ming (Inventor); Sha, Bingdong (Inventor)

2000-01-01

The matrix protein, M1, of influenza virus strain A/PR/8/34 has been purified from virions and crystallized. The crystals consist of a stable fragment (18 Kd) of the M1 protein. X-ray diffraction studies indicated that the crystals have a space group of P3.sub.t 21 or P3.sub.2 21. Vm calculations showed that there are two monomers in an asymmetric unit. A crystallized N-terminal domain of M1, wherein the N-terminal domain of M1 is crystallized such that the three dimensional structure of the crystallized N-terminal domain of M1 can be determined to a resolution of about 2.1 .ANG. or better, and wherein the three dimensional structure of the uncrystallized N-terminal domain of M1 cannot be determined to a resolution of about 2.1 .ANG. or better. A method of purifying M1 and a method of crystallizing M1. A method of using the three-dimensional crystal structure of M1 to screen for antiviral, influenza virus treating or preventing compounds. A method of using the three-dimensional crystal structure of M1 to screen for improved binding to or inhibition of influenza virus M1. The use of the three-dimensional crystal structure of the M1 protein of influenza virus in the manufacture of an inhibitor of influenza virus M1. The use of the three-dimensional crystal structure of the M1 protein of influenza virus in the screening of candidates for inhibition of influenza virus M1.

[Emodin alleviates pulmonary fibrosis through inactivation of TGF-β1/ADAMTS-1 signaling pathway in rats].

PubMed

Liu, Lijing; Qian, Hong; Xiao, Hua; He, Jianbin; Xie, Maofeng; Wang, Zaiyan; Long, Xingyun

2016-10-01

Objective To explore the role of transforming growth factor-β1 (TGF-β1)/a disintegrin-like and metalloproteinase with thrombospondin type 1 motif (ADAMTS-1) signaling pathway in emodin's anti-pulmonary fibrosis. Methods Sixty SD rats were randomly divided into 6 groups: normal control group, sham-operated group, model group, low-dose emodin intervention group (20 mg/kg), high-dose emodin intervention group (80 mg/kg) and prednisone group (5 mg/kg). Each group included 10 animals. Rats in the latter 4 groups were intratracheally injected with bleomycin A5 to induce pulmonary fibrosis, whereas bleomycin A5 was replaced by normal saline in sham-operated group. From the second day, rats in the low- and high-dose emodin intervention groups were intragastrically treated with 2 mL of 20 and 80 mg/kg emodin, respectively. Rats in the prednisone group were intragastrically administrated with 2 mL of 5 mg/kg prednisone acetate. However, rats in the normal control and sham-operated and model groups were treated with 2 mL of normal saline. All rats were sacrificed on day 28 after modeling. Subsequently, blood and pulmonary tissue specimen were taken. The pathological changes of pulmonary tissues were observed using routine HE and Masson staining. The expressions of TGF-β1, ADAMTS-1, collagen type 1 (Col1) and Col3 in pulmonary tissues were measured by quantitative real-time PCR and Western blotting. Serum levels of procollagen type 1 carboxy terminal propeptide (P1CP) and procollagen type 3 aminoterminal propeptide (P3NP) were detected by ELISA. Results Compare with the model group, the alveolitis and pulmonary fibrosis extent in each drug-treated group were significantly alleviated. In comparison with normal control group or sham-operated group, the mRNA and protein levels of TGF-β1, Col1 and Col3 in pulmonary tissues and the serum levels of P1CP and P3NP increased, but the mRNA and protein levels of ADAMTS-1 decreased in model group. After treatment with low- and high

Light intensity and N/P nutrient affect the accumulation of lipid and unsaturated fatty acids by Chlorella sp.

PubMed

Guo, Xiaoyi; Su, Gaomin; Li, Zheng; Chang, Jingyu; Zeng, Xianhai; Sun, Yong; Lu, Yinghua; Lin, Lu

2015-09-01

In this study, different light intensities (80, 160, 240 and 320 μmol/m(2) s) and various mediums including control medium (CM), N/P rich medium (NPM), N rich medium (NM), and P rich medium (PM) were applied for cultivation of Chlorella sp. It was revealed that cultivation of Chlorella sp. in CM under the light intensity of 320 μmol/m(2) s led to a lipid content up to 30% enhancement, which was higher than the results of other cases. A rather high unsaturated fatty acid (UFA) content of 7.5% and unsaturated fatty acid/total fatty acid (UFA/TFA) ratio of 0.73 were obtained under 320 μmol/m(2) s in CM, indicating that the CM-320 system was applicable for the generation of UFA. Moreover, Chlorella sp. cultivated in PM under 320 μmol/m(2) s provided higher TFA content (7.3%), which was appropriate for biofuel production. Copyright © 2015 Elsevier Ltd. All rights reserved.

An improved procedure, involving mass spectrometry, for N-terminal amino acid sequence determination of proteins which are N alpha-blocked.

PubMed Central

Rose, K; Kocher, H P; Blumberg, B M; Kolakofsky, D

1984-01-01

A modification to a previously described procedure [Gray & del Valle (1970) Biochemistry 9, 2134-2137; Rose, Simona & Offord (1983) Biochem. J. 215, 261-272] for mass-spectral identification of the N-terminal regions of proteins is shown to be useful in cases where the N-terminus is blocked. Three proteins were studied: vesicular-stomatitis-virus N protein, Sendai-virus NP protein, and a rabbit immunoglobulin lambda-light chain. These proteins, found to be blocked at the N-terminus with either the acetyl group or a pyroglutamic acid residue, had all failed to yield to attempted Edman degradation, in one case even after attempted enzymic removal of the pyroglutamic acid residue. The N-terminal regions of all three proteins were sequenced by using the new procedure. PMID:6421284

A model for the trap-assisted tunneling mechanism in diffused n-p and implanted n(+)-p HgCdTe photodiodes

NASA Technical Reports Server (NTRS)

Rosenfeld, David; Bahir, Gad

1992-01-01

This paper presents a theoretical model for the trap-assisted tunneling process in diffused n-on-p and implanted n(+)-on-p HgCdTe photodiodes. The model describes the connection between the leakage current associated with the traps and the trap characteristics: concentration, energy level, and capture cross sections. It is observed that the above two types of diodes differ the voltage dependence of the trap-assisted tunneling current and dynamic resistance. The model takes this difference into account and offers an explanation of the phenomenon. The good fit between measured and calculated dc characteristics of the photodiodes supports the validity of the model.

A model for the trap-assisted tunneling mechanism in diffused n-p and implanted n(+)-p HgCdTe photodiodes

NASA Technical Reports Server (NTRS)

Rosenfeld, David; Bahir, Gad

1992-01-01

A theoretical model for the trap-assisted tunneling process in diffused n-on-p and implanted n(+)-on-p HgCdTe photodiodes is presented. The model describes the traps and the trap characteristics: concentration, energy level, and capture cross sections. We have observed that the above two types of diodes differ in the voltage dependence of the trap-assisted tunneling current and dynamic resistance. Our model takes this difference into account and offers an explanation of the phenomenon. The good fit between measured and calculated DC characteristics of the photodiodes (for medium and high reverse bias and for temperatures from 65 to 140 K) supports the validity of the model.

The prognostic value of pre-operative and post-operative B-type natriuretic peptides in patients undergoing noncardiac surgery: B-type natriuretic peptide and N-terminal fragment of pro-B-type natriuretic peptide: a systematic review and individual patient data meta-analysis.

PubMed

Rodseth, Reitze N; Biccard, Bruce M; Le Manach, Yannick; Sessler, Daniel I; Lurati Buse, Giovana A; Thabane, Lehana; Schutt, Robert C; Bolliger, Daniel; Cagini, Lucio; Cardinale, Daniela; Chong, Carol P W; Chu, Rong; Cnotliwy, Miłosław; Di Somma, Salvatore; Fahrner, René; Lim, Wen Kwang; Mahla, Elisabeth; Manikandan, Ramaswamy; Puma, Francesco; Pyun, Wook B; Radović, Milan; Rajagopalan, Sriram; Suttie, Stuart; Vanniyasingam, Thuvaraha; van Gaal, William J; Waliszek, Marek; Devereaux, P J

2014-01-21

The objective of this study was to determine whether measuring post-operative B-type natriuretic peptides (NPs) (i.e., B-type natriuretic peptide [BNP] and N-terminal fragment of proBNP [NT-proBNP]) enhances risk stratification in adult patients undergoing noncardiac surgery, in whom a pre-operative NP has been measured. Pre-operative NP concentrations are powerful independent predictors of perioperative cardiovascular complications, but recent studies have reported that elevated post-operative NP concentrations are independently associated with these complications. It is not clear whether there is value in measuring post-operative NP when a pre-operative measurement has been done. We conducted a systematic review and individual patient data meta-analysis to determine whether the addition of post-operative NP levels enhanced the prediction of the composite of death and nonfatal myocardial infarction at 30 and ≥180 days after surgery. Eighteen eligible studies provided individual patient data (n = 2,179). Adding post-operative NP to a risk prediction model containing pre-operative NP improved model fit and risk classification at both 30 days (corrected quasi-likelihood under the independence model criterion: 1,280 to 1,204; net reclassification index: 20%; p < 0.001) and ≥180 days (corrected quasi-likelihood under the independence model criterion: 1,320 to 1,300; net reclassification index: 11%; p = 0.003). Elevated post-operative NP was the strongest independent predictor of the primary outcome at 30 days (odds ratio: 3.7; 95% confidence interval: 2.2 to 6.2; p < 0.001) and ≥180 days (odds ratio: 2.2; 95% confidence interval: 1.9 to 2.7; p < 0.001) after surgery. Additional post-operative NP measurement enhanced risk stratification for the composite outcomes of death or nonfatal myocardial infarction at 30 days and ≥180 days after noncardiac surgery compared with a pre-operative NP measurement alone. Copyright © 2014 American College of Cardiology

Band structure engineering of TiO2 nanowires by n-p codoping for enhanced visible-light photoelectrochemical water-splitting.

PubMed

Zhang, Daoyu; Yang, Minnan

2013-11-14

The advantages of one-dimensional nanostructures, such as excellent charge separation and charge transport, low charge carrier recombination losses and so on, render them the photocatalysts of choice for many applications that exploit solar energy. In this work, based on very recently synthesized ultrathin anatase TiO2 nanowires, we explore the possibility of these wires as photocatalysts for photoelectrochemical water-splitting via the mono-doping (C, N, V, and Cr) and n-p codoping (C&V, C&Cr, N&V, and N&Cr) schemes. Our first-principles calculations predict that the C&Cr and C&V codoped ANWs may be strong candidates for photoelectrochemical water-splitting, because they have a substantially reduced band gap of 2.49 eV, appropriate band edge positions, no carrier recombination centers, and enhanced optical absorption in the visible light region.

NpPDR1, a Pleiotropic Drug Resistance-Type ATP-Binding Cassette Transporter from Nicotiana plumbaginifolia, Plays a Major Role in Plant Pathogen Defense1

PubMed Central

Stukkens, Yvan; Bultreys, Alain; Grec, Sébastien; Trombik, Tomasz; Vanham, Delphine; Boutry, Marc

2005-01-01

Nicotiana plumbaginifolia NpPDR1, a plasma membrane pleiotropic drug resistance-type ATP-binding cassette transporter formerly named NpABC1, has been suggested to transport the diterpene sclareol, an antifungal compound. However, direct evidence for a role of pleiotropic drug resistance transporters in the plant defense is still lacking. In situ immunolocalization and histochemical analysis using the gusA reporter gene showed that NpPDR1 was constitutively expressed in the whole root, in the leaf glandular trichomes, and in the flower petals. However, NpPDR1 expression was induced in the whole leaf following infection with the fungus Botrytis cinerea, and the bacteria Pseudomonas syringae pv tabaci, Pseudomonas fluorescens, and Pseudomonas marginalis pv marginalis, which do not induce a hypersensitive response in N. plumbaginifolia, whereas a weaker response was observed using P. syringae pv syringae, which does induce a hypersensitive response. Induced NpPDR1 expression was more associated with the jasmonic acid than the salicylic acid signaling pathway. These data suggest that NpPDR1 is involved in both constitutive and jasmonic acid-dependent induced defense. Transgenic plants in which NpPDR1 expression was prevented by RNA interference showed increased sensitivity to sclareol and reduced resistance to B. cinerea. These data show that NpPDR1 is involved in pathogen resistance and thus demonstrate a new role for the ATP-binding cassette transporter family. PMID:16126865

POTASSIUM CITRATE DECREASES BONE RESORPTION IN POSTMENOPAUSAL WOMEN WITH OSTEOPENIA: A RANDOMIZED, DOUBLE-BLIND CLINICAL TRIAL.

PubMed

Gregory, Naina Sinha; Kumar, Rekha; Stein, Emily M; Alexander, Ellen; Christos, Paul; Bockman, Richard S; Rodman, John S

2015-12-01

Diets rich in animal protein, such as the typical American diet, are thought to create a high acid load. An association between acid load and bone loss has led to the idea that providing positive alkaline salt therapy could have beneficial effects on bone metabolism. The objective of this study was to investigate the effects of potassium citrate (K-citrate), 40 mEq daily, over 1 year on bone resorption and formation. A randomized, double-blind, placebo-controlled trial of 83 women with postmenopausal osteopenia. Levels of bone turnover markers, specifically urinary N-telopeptide of collagen type 1 (u-NTX), amino-terminal propeptide of type 1 procollagen (P1NP), bone-specific alkaline phosphatase (BSAP), and osteocalcin (OC) were compared. Changes in bone mineral density (BMD) were also examined. K-citrate decreased both u-NTX (P = .005) and serum P1NP (P<.001) starting at month 1 and continuing through month 12. No significant change was seen in BSAP or OC. No significant change was seen in lumbar or hip BMD between the 2 groups. In women with postmenopausal osteopenia, treatment with K-citrate for 1 year resulted in a significant decrease in markers of turnover. The effect on markers of bone formation was not consistent. K-citrate may serve as a potential treatment for bone loss that is well tolerated and without any significant known long-term consequences.

Measurements of n-p correlations in the reaction of relativistic neon with uranium

NASA Technical Reports Server (NTRS)

Frankel, K.; Schimmerling, W.; Rasmussen, J. O.; Crowe, K. M.; Bistirlich, J.; Bowman, H.; Hashimoto, O.; Murphy, D. L.; Ridout, J.; Sullivan, J. P.;

Estradiol In Females May Negate Skeletal Muscle Myostatin Mrna Expression And Serum Myostatin Propeptide Levels After Eccentric Muscle Contractions

PubMed Central

Willoughby, Darryn S.; Wilborn, Colin D.

2006-01-01

Eccentric contractions produce a significant degree of inflammation and muscle injury that may increase the expression of myostatin. Due to its anti- oxidant and anti-flammatory effects, circulating 17-β estradiol (E2) may attenuate myostatin expression. Eight males and eight females performed 7 sets of 10 reps of eccentric contractions of the knee extensors at 150% 1-RM. Each female performed the eccentric exercise bout on a day that fell within her mid-luteal phase (d 21-23 of her 28-d cycle). Blood and muscle samples were obtained before and 6 and 24 h after exercise, while additional blood samples were obtained at 48 and 72 h after exercise. Serum E2 and myostatin LAP/propeptide (LAP/pro) levels were determined with ELISA, and myostatin mRNA expression determined using RT-PCR. Data were analyzed with two-way ANOVA and bivariate correlations (p < 0.05). Females had greater levels of serum E2 throughout the 72- h sampling period (p < 0.05). While males had greater body mass and fat-free mass, neither was correlated to the pre-exercise levels of myostatin mRNA and LAP/pro for either gender (p > 0.05). Compared to pre-exercise, males had significant increases (p < 0.05) in LAP/propetide and mRNA of 78% and 28%, respectively, at 24 h post-exercise, whereas females underwent respective decreases of 10% and 21%. E2 and LAP/propeptide were correlated at 6 h (r = -0.804, p = 0.016) and 24 h post- exercise (r = -0.841, p = 0.009) in males, whereas in females E2 levels were correlated to myostatin mRNA at 6 h (r =0.739, p = 0.036) and 24 h (r = 0.813, p = 0.014) post-exercise and LAP/propeptide at 6 h (r = 0.713, p = 0.047) and 24 h (r = 0.735, p = 0.038). In females, myostatin mRNA expression and serum LAP/propeptide levels do not appear to be significantly up-regulated following eccentric exercise, and may be due to higher levels of circulating E2. Key Points The pre-exercise levels of myostatin mRNA and propeptide were not significantly different between genders, and

C-terminal cleavage of DeltaNp63alpha is associated with TSA-induced apoptosis in immortalized corneal epithelial cells.

PubMed

Robertson, Danielle M; Ho, Su-Inn; Cavanagh, H Dwight

2010-08-01

In the central human corneal epithelium, loss of DeltaNp63 occurs in all surface epithelial cells preparing to undergo desquamation, suggesting a potential role for DeltaNp63 isoforms in mediating surface cell apoptotic shedding. In this study, the authors investigated a role for DeltaNp63 isoforms in caspase-mediated apoptosis in a telomerase-immortalized corneal epithelial cell line. For in vitro studies, hTCEpi cells were cultured in KGM-2 serum-free culture media containing 0.15 mM calcium. To assess dynamic protein interactions among individual DeltaNp63 isoforms, DeltaNp63-EGFP expression plasmids were transiently expressed in hTCEpi cells and evaluated by FRAP. Trichostatin-A (TSA; 3.31 muM) was used to induce cell death as measured by caspase activity. Cleavage and loss of endogenous DeltaNp63alpha, DeltaNp63-EGFP expression plasmids, and p53 were assessed after treatment with TSA and siRNA. Transient expression of DeltaNp63-EGFP alpha and beta isoforms resulted in the formation of a smaller isoform similar in size to DeltaNp63gamma-EGFP. FRAP demonstrated that DeltaNp63alpha-EGFP has greater immobile fraction than beta or gamma. TSA induced caspase-mediated apoptotic pathways; caspase induction was accompanied by a decrease in endogenous DeltaNp63alpha and p53. TSA upregulated DeltaNp63-EGFP plasmid expression; this was accompanied by a selective increase in cleavage of DeltaNp63alpha-EGFP. siRNA knockdown of DeltaNp63alpha correlated with a reduction in p53 independently of TSA. DeltaNp63alpha is the dominant active isoform in corneal epithelial cell nuclei. Loss of DeltaNp63alpha occurs during apoptotic signaling by cleavage at the C terminus. The corresponding loss of p53 suggests that a significant relationship appears to exist between these two regulatory proteins.

Opioid and neurokinin activities of substance P fragments and their analogs.

PubMed

Lei, S Z; Lipkowski, A W; Wilcox, G L

1991-02-07

Newly developed substance P (SP) analogs with altered N-terminal sequences which equalize the lipophilicity of the N-terminal and C-terminal elements and of their fusion product were examined using i.t. injection in mice. I.t. injection of either the full length analog or the C-terminal hexapeptide (CP) produced biting and scratching behavior similar to that elicited by SP. SPF was approximately 5-fold and CP 14-fold less potent than native SP. The N-terminal peptide (NP) was inactive by itself but inhibited CP-elicited behavior. Naloxone antagonized this action of NP and shifted the SPF dose-response curve 4-fold to the left. However, naloxone had no effect on the action of CP or on the action of any of the native neurokinins. The results are consistent with the hypothesis that N- and C-terminal analogs of SP can have opioid and SP-like actions, respectively, in the CNS of rodents. Furthermore, analogs of SP which include at least the terminal tetrapeptide retain neurokinin activity.

Effect of carbohydrate feeding on the bone metabolic response to running

PubMed Central

Varley, Ian; Jones, Thomas W.; James, Ruth M.; Tang, Jonathan C. Y.; Fraser, William D.; Greeves, Julie P.

2015-01-01

Bone resorption is increased after running, with no change in bone formation. Feeding during exercise might attenuate this increase, preventing associated problems for bone. This study investigated the immediate and short-term bone metabolic responses to carbohydrate (CHO) feeding during treadmill running. Ten men completed two 7-day trials, once being fed CHO (8% glucose immediately before, every 20 min during, and immediately after exercise at a rate of 0.7 g CHO·kg body mass−1·h−1) and once being fed placebo (PBO). On day 4 of each trial, participants completed a 120-min treadmill run at 70% of maximal oxygen consumption (V̇o2 max). Blood was taken at baseline (BASE), immediately after exercise (EE), after 60 (R1) and 120 (R2) min of recovery, and on three follow-up days (FU1-FU3). Markers of bone resorption [COOH-terminal telopeptide region of collagen type 1 (β-CTX)] and formation [NH2-terminal propeptides of procollagen type 1 (P1NP)] were measured, along with osteocalcin (OC), parathyroid hormone (PTH), albumin-adjusted calcium (ACa), phosphate, glucagon-like peptide-2 (GLP-2), interleukin-6 (IL-6), insulin, cortisol, leptin, and osteoprotogerin (OPG). Area under the curve was calculated in terms of the immediate (BASE, EE, R1, and R2) and short-term (BASE, FU1, FU2, and FU3) responses to exercise. β-CTX, P1NP, and IL-6 responses to exercise were significantly lower in the immediate postexercise period with CHO feeding compared with PBO (β-CTX: P = 0.028; P1NP: P = 0.021; IL-6: P = 0.036), although there was no difference in the short-term response (β-CTX: P = 0.856; P1NP: P = 0.721; IL-6: P = 0.327). No other variable was significantly affected by CHO feeding during exercise. We conclude that CHO feeding during exercise attenuated the β-CTX and P1NP responses in the hours but not days following exercise, indicating an acute effect of CHO feeding on bone turnover. PMID:26251510

Membrane interaction of the N-terminal domain of chemokine receptor CXCR1.

PubMed

Haldar, Sourav; Raghuraman, H; Namani, Trishool; Rajarathnam, Krishna; Chattopadhyay, Amitabha

2010-06-01

The N-terminal domain of chemokine receptors constitutes one of the two critical ligand binding sites, and plays important roles by mediating binding affinity, receptor selectivity, and regulating function. In this work, we monitored the organization and dynamics of a 34-mer peptide of the CXC chemokine receptor 1 (CXCR1) N-terminal domain and its interaction with membranes by utilizing a combination of fluorescence-based approaches and surface pressure measurements. Our results show that the CXCR1 N-domain 34-mer peptide binds vesicles of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and upon binding, the tryptophan residues of the peptide experience motional restriction and exhibit red edge excitation shift (REES) of 19nm. These results are further supported by increase in fluorescence anisotropy and mean fluorescence lifetime upon membrane binding. These results constitute one of the first reports demonstrating membrane interaction of the N-terminal domain of CXCR1 and gain relevance in the context of the emerging role of cellular membranes in chemokine signaling.

Resonant Auger decay studies in Kr 3d{sub 3/2,5/2}{sup {minus}1}np states using angle-resolved electron imaging spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farhat, A.; Wills, A.A.; Berrah, N.

1999-01-01

An extensive and detailed mapping of the resonant Auger decay of all the photoexcited 3d{sub 3/2,5/2}{sup {minus}1}np states in Kr has been performed using angle-resolved two-dimensional photoelectron spectroscopy at the Advanced Light Source at Lawrence Berkeley National Laboratory. This has allowed us to obtain angular distributions and spectator and shake probabilities for the Kr 3d{sup {minus}1}np{r_arrow}4s{sup {minus}1}4p{sup {minus}1}({sup 1}P)mp+e{sup {minus}} (n=5{endash}9, m=5{endash}11) resonance Auger decays. The results show that the spectator-core coupling is strong at lower {ital n} (n=5,6) but lessens for higher {ital n}, with a shake-up of m=n+1 preferred. The observed trend is in good agreement with themore » previous experimental and theoretical spectator and shake probabilities for these transitions and also with the analogous decay to the 4s{sup 2}4p{sup 4}mp states [H. Aksela {ital et al.}, Phys. Rev. Lett. {bold 25}, 4970 (1997)]. However, to our knowledge, no prior angular distribution measurements for the Kr 3d{sup {minus}1}np{r_arrow}4s{sup {minus}1}4p{sup {minus}1}({sup 1}P)mp+e{sup {minus}} (n=5{endash}9, m=5{endash}11) resonant Auger decay has been reported. These are found to also show similar behavior to the decay to the 4s{sup 2}4p{sup 4}mp states. {copyright} {ital 1999} {ital The American Physical Society}« less

GBNV encoded movement protein (NSm) remodels ER network via C-terminal coiled coil domain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Pratibha; Savithri, H.S., E-mail: bchss@biochem.iisc.ernet.in

Plant viruses exploit the host machinery for targeting the viral genome–movement protein complex to plasmodesmata (PD). The mechanism by which the non-structural protein m (NSm) of Groundnut bud necrosis virus (GBNV) is targeted to PD was investigated using Agrobacterium mediated transient expression of NSm and its fusion proteins in Nicotiana benthamiana. GFP:NSm formed punctuate structures that colocalized with mCherry:plasmodesmata localized protein 1a (PDLP 1a) confirming that GBNV NSm localizes to PD. Unlike in other movement proteins, the C-terminal coiled coil domain of GBNV NSm was shown to be involved in the localization of NSm to PD, as deletion of thismore » domain resulted in the cytoplasmic localization of NSm. Treatment with Brefeldin A demonstrated the role of ER in targeting GFP NSm to PD. Furthermore, mCherry:NSm co-localized with ER–GFP (endoplasmic reticulum targeting peptide (HDEL peptide fused with GFP). Co-expression of NSm with ER–GFP showed that the ER-network was transformed into vesicles indicating that NSm interacts with ER and remodels it. Mutations in the conserved hydrophobic region of NSm (residues 130–138) did not abolish the formation of vesicles. Additionally, the conserved prolines at positions 140 and 142 were found to be essential for targeting the vesicles to the cell membrane. Further, systematic deletion of amino acid residues from N- and C-terminus demonstrated that N-terminal 203 amino acids are dispensable for the vesicle formation. On the other hand, the C-terminal coiled coil domain when expressed alone could also form vesicles. These results suggest that GBNV NSm remodels the ER network by forming vesicles via its interaction through the C-terminal coiled coil domain. Interestingly, NSm interacts with NP in vitro and coexpression of these two proteins in planta resulted in the relocalization of NP to PD and this relocalization was abolished when the N-terminal unfolded region of NSm was deleted. Thus, the NSm

High selectivity of colorimetric detection of p-nitrophenol based on Ag nanoclusters

NASA Astrophysics Data System (ADS)

Qu, Fei; Chen, Ping; Zhu, Shuyun; You, Jinmao

2017-01-01

Ag nanoclusters (Ag NCs) templated by hyperbranched polyethyleneimine (PEI) with different terminal groups and molecular weights had been developed as a special optical sensor for detecting p-nitrophenol (p-NP). When adding p-NP into Ag NCs, an obvious color change from pale yellow to deep yellow could be observed by naked eyes, accompanying with an apparent red-shift of absorption peak, and the reason was attributed to the formation of oxygen anion of p-NP based on the transfer of H+ from p-NP to amine groups of PEI. The molecular weights of template would greatly affect the sensitivity of p-NP. Ag NCs capped by PEI terminated ethylenediamine (EDA) possessed better sensitivity than other Ag NCs, showing good linear range from 5 to 140 μM with the limit of detection as low as 1.28 μM. Most importantly, this present system displayed high selectivity toward p-NP even in the presence of other nitrophenols and nitrotoluenes. This reliable method had been successfully applied for the detection of p-NP in real water and soil samples.

Acute changes in biochemical markers of bone resorption and formation after Thai traditional massage.

PubMed

Saetung, Sunee; Chailurkit, La-or; Ongphiphadhanakul, Boonsong

2010-07-01

Mechanical loadings by active exercise or passive low amplitude vibration have been demonstrated to enhance bone mass or delay bone loss. Traditional Thai massage can be anabolic to bone due to the application of physical loading on the body in a rhythmic fashion. To explore the skeletal effect of Thai traditional massage by examining the changes in biochemical markers of bone turnover immediately after the massage. Subjects consisted of 30 healthy females aged 20-40 years. Each subject received Thai traditional massage for 2 hours by a single masseuse. Bone mineral density (BMD) at baseline was measured by dual-energy X-ray absorptiometry (DEXA). C-terminal telopeptide of type 1 collagen (CTx-I) and total procollagen type 1 amino-terminal propeptide (P1NP) were determined by electrochemiluminescence immunoassay. There was a 4.8% increase in serum P1NP concentrations after massage (median 43.4 ng/ml vs. 41.3 ng/ml, p < 0.05). Serum CTx-I also decreased after massage (median 2-hour vs. baseline 0.29 ng/ml vs. 0.31 ng/ml, p < 0.05). There was a nearly significant negative correlation between the percentage change in serum P1NP and BMD at the total femur (r = -0.37, p = 0.056) whereas the statistically significant correlation disappeared between percentage change in bone turnover and the other sites of BMD. Thai traditional massage induces acute changes in bone formation and resorption markers. Study on the more prolonged effects of Thai traditional massage is warranted to explore its implication in the enhancement of bone health.

Mcl1 regulates the terminal mitosis of neural precursor cells in the mammalian brain through p27Kip1.

PubMed

Hasan, S M Mahmudul; Sheen, Ashley D; Power, Angela M; Langevin, Lisa Marie; Xiong, Jieying; Furlong, Michael; Day, Kristine; Schuurmans, Carol; Opferman, Joseph T; Vanderluit, Jacqueline L

2013-08-01

Cortical development requires the precise timing of neural precursor cell (NPC) terminal mitosis. Although cell cycle proteins regulate terminal mitosis, the factors that influence the cell cycle machinery are incompletely understood. Here we show in mice that myeloid cell leukemia 1 (Mcl1), an anti-apoptotic Bcl-2 protein required for the survival of NPCs, also regulates their terminal differentiation through the cell cycle regulator p27(Kip1). A BrdU-Ki67 cell profiling assay revealed that in utero electroporation of Mcl1 into NPCs in the embryonic neocortex increased NPC cell cycle exit (the leaving fraction). This was further supported by a decrease in proliferating NPCs (Pax6(+) radial glial cells and Tbr2(+) neural progenitors) and an increase in differentiating cells (Dcx(+) neuroblasts and Tbr1(+) neurons). Similarly, BrdU birth dating demonstrated that Mcl1 promotes premature NPC terminal mitosis giving rise to neurons of the deeper cortical layers, confirming their earlier birthdate. Changes in Mcl1 expression within NPCs caused concomitant changes in the levels of p27(Kip1) protein, a key regulator of NPC differentiation. Furthermore, in the absence of p27(Kip1), Mcl1 failed to induce NPC cell cycle exit, demonstrating that p27(Kip1) is required for Mcl1-mediated NPC terminal mitosis. In summary, we have identified a novel physiological role for anti-apoptotic Mcl1 in regulating NPC terminal differentiation.

First-Principle Study of the Optical Properties of Dilute-P GaN1-xPx Alloys.

PubMed

Borovac, Damir; Tan, Chee-Keong; Tansu, Nelson

2018-04-16

An investigation on the optical properties of dilute-P GaN 1-x P x alloys by First-Principle Density Functional Theory (DFT) methods is presented, for phosphorus (P) content varying from 0% up to 12.5%. Findings on the imaginary and real part of the dielectric function are analyzed and the results are compared with previously reported theoretical works on GaN. The complex refractive index, normal-incidence reflectivity and birefringence are presented and a difference in the refractive index in the visible regime between GaN and GaNP alloys of ~0.3 can be engineered by adding minute amounts of phosphorus, indicating strong potential for refractive index tunability. The optical properties of the GaN 1-x P x alloys indicate their strong potential for implementation in various III-nitride-based photonic waveguide applications and Distributed Bragg Reflectors (DBR).

p-n Junction Diodes Fabricated on Si-Si/Ge Heteroepitaxial Films

NASA Technical Reports Server (NTRS)

Das, K.; Mazumder, M. D. A.; Hall, H.; Alterovitz, Samuel A. (Technical Monitor)

2000-01-01

A set of photolithographic masks was designed for the fabrication of diodes in the Si-Si/Ge material system. Fabrication was performed on samples obtained from two different wafers: (1) a complete HBT structure with an n (Si emitter), p (Si/Ge base), and an n/n+ (Si collector/sub-collector) deposited epitaxially (MBE) on a high resistivity p-Si substrate, (2) an HBT structure where epitaxial growth was terminated after the p-type base (Si/Ge) layer deposition. Two different process runs were attempted for the fabrication of Si-Si/Ge (n-p) and Si/Ge-Si (p-n) junction diodes formed between the emitter-base and base-collector layers, respectively, of the Si-Si/Ge-Si HBT structure. One of the processes employed a plasma etching step to expose the p-layer in the structure (1) and to expose the e-layer in structure (2). The Contact metallization used for these diodes was a Cu-based metallization scheme that was developed during the first year of the grant. The plasma-etched base-collector diodes on structure (2) exhibited well-behaved diode-like characteristics. However, the plasma-etched emitter-base diodes demonstrated back-to-back diode characteristics. These back-to back characteristics were probably due to complete etching of the base-layer, yielding a p-n-p diode. The deep implantation process yielded rectifying diodes with asymmetric forward and reverse characteristics. The ideality factor of these diodes were between 1.6 -2.1, indicating that the quality of the MBE grown epitaxial films was not sufficiently high, and also incomplete annealing of the implantation damage. Further study will be conducted on CVD grown films, which are expected to have higher epitaxial quality.

The C-terminal region of lymphocytic choriomeningitis virus nucleoprotein contains distinct and segregable functional domains involved in NP-Z interaction and counteraction of the type I interferon response.

PubMed

Ortiz-Riaño, Emilio; Cheng, Benson Yee Hin; de la Torre, Juan Carlos; Martínez-Sobrido, Luis

2011-12-01

Several arenaviruses cause hemorrhagic fever (HF) disease in humans that is associated with high morbidity and significant mortality. Arenavirus nucleoprotein (NP), the most abundant viral protein in infected cells and virions, encapsidates the viral genome RNA, and this NP-RNA complex, together with the viral L polymerase, forms the viral ribonucleoprotein (vRNP) that directs viral RNA replication and gene transcription. Formation of infectious arenavirus progeny requires packaging of vRNPs into budding particles, a process in which arenavirus matrix-like protein (Z) plays a central role. In the present study, we have characterized the NP-Z interaction for the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV). The LCMV NP domain that interacted with Z overlapped with a previously documented C-terminal domain that counteracts the host type I interferon (IFN) response. However, we found that single amino acid mutations that affect the anti-IFN function of LCMV NP did not disrupt the NP-Z interaction, suggesting that within the C-terminal region of NP different amino acid residues critically contribute to these two distinct and segregable NP functions. A similar NP-Z interaction was confirmed for the HF arenavirus Lassa virus (LASV). Notably, LCMV NP interacted similarly with both LCMV Z and LASV Z, while LASV NP interacted only with LASV Z. Our results also suggest the presence of a conserved protein domain within NP but with specific amino acid residues playing key roles in determining the specificity of NP-Z interaction that may influence the viability of reassortant arenaviruses. In addition, this NP-Z interaction represents a potential target for the development of antiviral drugs to combat human-pathogenic arenaviruses.

Bone Turnover Status: Classification Model and Clinical Implications

PubMed Central

Fisher, Alexander; Fisher, Leon; Srikusalanukul, Wichat; Smith, Paul N

2018-01-01

Aim: To develop a practical model for classification bone turnover status and evaluate its clinical usefulness. Methods: Our classification of bone turnover status is based on internationally recommended biomarkers of both bone formation (N-terminal propeptide of type1 procollagen, P1NP) and bone resorption (beta C-terminal cross-linked telopeptide of type I collagen, bCTX), using the cutoffs proposed as therapeutic targets. The relationships between turnover subtypes and clinical characteristic were assessed in1223 hospitalised orthogeriatric patients (846 women, 377 men; mean age 78.1±9.50 years): 451(36.9%) subjects with hip fracture (HF), 396(32.4%) with other non-vertebral (non-HF) fractures (HF) and 376 (30.7%) patients without fractures. Resalts: Six subtypes of bone turnover status were identified: 1 - normal turnover (P1NP>32 μg/L, bCTX≤0.250 μg/L and P1NP/bCTX>100.0[(median value]); 2- low bone formation (P1NP ≤32 μg/L), normal bone resorption (bCTX≤0.250 μg/L) and P1NP/bCTX>100.0 (subtype2A) or P1NP/bCTX<100.0 (subtype 2B); 3- low bone formation, high bone resorption (bCTX>0.250 μg/L) and P1NP/bCTX<100.0; 4- high bone turnover (both markers elevated ) and P1NP/bCTX>100.0 (subtype 4A) or P1NP/bCTX<100.0 (subtype 4B). Compared to subtypes 1 and 2A, subtype 2B was strongly associated with nonvertebral fractures (odds ratio [OR] 2.0), especially HF (OR 3.2), age>75 years and hyperparathyroidism. Hypoalbuminaemia and not using osteoporotic therapy were two independent indicators common for subtypes 3, 4A and 4B; these three subtypes were associated with in-hospital mortality. Subtype 3 was associated with fractures (OR 1.7, for HF OR 2.4), age>75 years, chronic heart failure (CHF), anaemia, and history of malignancy, and predicted post-operative myocardial injury, high inflammatory response and length of hospital stay (LOS) above10 days. Subtype 4A was associated with chronic kidney disease (CKD), anaemia, history of malignancy and walking aids

Osteocalcin carboxylation is not associated with body weight or percent fat changes during weight loss in post-menopausal women.

PubMed

Centi, Amanda J; Booth, Sarah L; Gundberg, Caren M; Saltzman, Edward; Nicklas, Barbara; Shea, M Kyla

2015-12-01

Osteocalcin (OC) is a vitamin K-dependent bone protein used as a marker of bone formation. Mouse models have demonstrated a role for the uncarboxylated form of OC (ucOC) in energy metabolism, including energy expenditure and adiposity, but human data are equivocal. The purpose of this study was to determine the associations between changes in measures of OC and changes in body weight and percent body fat in obese, but otherwise healthy post-menopausal women undergoing a 20-week weight loss program. All participants received supplemental vitamins K and D and calcium. Body weight and body fat percentage (%BF) were assessed before and after the intervention. Serum OC [(total (tOC), ucOC, percent uncarboxylated (%ucOC)], and procollagen type 1N-terminal propeptide (P1NP; a measure of bone formation) were measured. Women lost an average of 10.9 ± 3.9 kg and 4 %BF. Serum concentrations of tOC, ucOC, %ucOC, and P1NP did not significantly change over the twenty-week intervention, nor were these measures associated with changes in weight (all p > 0.27) or %BF (all p > 0.54). Our data do not support an association between any serum measure of OC and weight or %BF loss in post-menopausal women supplemented with nutrients implicated in bone health.

Role of N-terminal 28-amino-acid region of Rhizopus oryzae lipase in directing proteins to secretory pathway of Aspergillus oryzae.

PubMed

Hama, Shinji; Tamalampudi, Sriappareddy; Shindo, Naoki; Numata, Takao; Yamaji, Hideki; Fukuda, Hideki; Kondo, Akihiko

2008-07-01

To develop a new approach for improving heterologous protein production in Aspergillus oryzae, we focused on the functional role of the N-terminal region of Rhizopus oryzae lipase (ROL). Several N-terminal deletion variants of ROL were expressed in A. oryzae. Interestingly, a segment of 28 amino acids from the C-terminal region of the propeptide (N28) was found to be critical for secretion of ROL into the culture medium. To further investigate the role of N28, the ROL secretory process was visualized in vivo using ROL-green fluorescent protein (GFP) fusion proteins. In cells producing ROL with N28, fluorescence observations showed that the fusion proteins are transported through endoplasmic reticulum (ER), Golgi, and cell wall, which is one of the typical secretory processes in a eukaryotic cell. Because the expression of the mature ROL-GFP fusion protein induced fluorescence accumulation without its translocation into the ER, N28 is considered to play a crucial role in protein transport. When N28 was inserted between the secretion signal and GFP, fluorescence observations showed that GFP, which is originally a cytoplasmic protein, was efficiently translocated into the ER of A. oryzae, resulting in an enhanced secretion of mature GFP after proteolytic cleavage of N28. These findings suggest that N28 facilitates protein translocation into ER and can be a promising candidate for improving heterologous protein production in A. oryzae.

Select human cancer mutants of NRMT1 alter its catalytic activity and decrease N-terminal trimethylation.

PubMed

Shields, Kaitlyn M; Tooley, John G; Petkowski, Janusz J; Wilkey, Daniel W; Garbett, Nichola C; Merchant, Michael L; Cheng, Alan; Schaner Tooley, Christine E

2017-08-01

A subset of B-cell lymphoma patients have dominant mutations in the histone H3 lysine 27 (H3K27) methyltransferase EZH2, which change it from a monomethylase to a trimethylase. These mutations occur in aromatic resides surrounding the active site and increase growth and alter transcription. We study the N-terminal trimethylase NRMT1 and the N-terminal monomethylase NRMT2. They are 50% identical, but differ in key aromatic residues in their active site. Given how these residues affect EZH2 activity, we tested whether they are responsible for the distinct catalytic activities of NRMT1/2. Additionally, NRMT1 acts as a tumor suppressor in breast cancer cells. Its loss promotes oncogenic phenotypes but sensitizes cells to DNA damage. Mutations of NRMT1 naturally occur in human cancers, and we tested a select group for altered activity. While directed mutation of the aromatic residues had minimal catalytic effect, NRMT1 mutants N209I (endometrial cancer) and P211S (lung cancer) displayed decreased trimethylase and increased monomethylase/dimethylase activity. Both mutations are located in the peptide-binding channel and indicate a second structural region impacting enzyme specificity. The NRMT1 mutants demonstrated a slower rate of trimethylation and a requirement for higher substrate concentration. Expression of the mutants in wild type NRMT backgrounds showed no change in N-terminal methylation levels or growth rates, demonstrating they are not acting as dominant negatives. Expression of the mutants in cells lacking endogenous NRMT1 resulted in minimal accumulation of N-terminal trimethylation, indicating homozygosity could help drive oncogenesis or serve as a marker for sensitivity to DNA damaging chemotherapeutics or γ-irradiation. © 2017 The Protein Society.

High bone turnover elevates the risk of denosumab-induced hypocalcemia in women with postmenopausal osteoporosis

PubMed Central

Ishikawa, Koji; Nagai, Takashi; Sakamoto, Keizo; Ohara, Kenji; Eguro, Takeshi; Ito, Hiroshi; Toyoshima, Yoichi; Kokaze, Akatsuki; Toyone, Tomoaki; Inagaki, Katsunori

2016-01-01

Hypocalcemia is the most common major adverse event in patients with osteoporosis receiving the bone resorption inhibitor denosumab; however, limited information is available regarding risk factors of hypocalcemia. Therefore, this study aimed to identify the risk factors of hypocalcemia induced by denosumab treatment for osteoporosis. We retrospectively reviewed the records of patients who had received initial denosumab supplemented with activated vitamin D for osteoporosis. Serum levels of the following bone turnover markers (BTMs) were measured at baseline: bone-specific alkaline phosphatase (BAP), total N-terminal propeptide of type 1 procollagen (P1NP), tartrate-resistant acid phosphatase 5b (TRACP-5b), and urinary cross-linked N-telopeptide of type 1 collagen (NTX). Of the 85 denosumab-treated patients with osteoporosis studied, 22 (25.9%) developed hypocalcemia. Baseline serum total P1NP, TRACP-5b, and urinary NTX were significantly higher in patients with hypocalcemia than in those with normocalcemia following denosumab administration (all P<0.01). Multivariate logistic regression analysis revealed that patients with total P1NP >76.5 μg/L, TRACP-5b >474 mU/dL, or urinary NTX >49.5 nmol bone collagen equivalent/mmol creatinine had a higher risk of hypocalcemia (P<0.01). Our study suggests that denosumab may have a greater impact on serum calcium levels in patients with postmenopausal osteoporosis with higher baseline bone turnover than in patients with postmenopausal osteoporosis with normal baseline bone turnover, because maintenance of normal serum calcium in this subgroup is more dependent on bone resorption. Close monitoring of serum calcium levels is strongly recommended for denosumab-treated patients with high bone turnover, despite supplementation with activated vitamin D and oral calcium. PMID:27980413

A Dbf4p BRCA1 C-Terminal-Like Domain Required for the Response to Replication Fork Arrest in Budding Yeast

PubMed Central

Gabrielse, Carrie; Miller, Charles T.; McConnell, Kristopher H.; DeWard, Aaron; Fox, Catherine A.; Weinreich, Michael

2006-01-01

Dbf4p is an essential regulatory subunit of the Cdc7p kinase required for the initiation of DNA replication. Cdc7p and Dbf4p orthologs have also been shown to function in the response to DNA damage. A previous Dbf4p multiple sequence alignment identified a conserved ∼40-residue N-terminal region with similarity to the BRCA1 C-terminal (BRCT) motif called “motif N.” BRCT motifs encode ∼100-amino-acid domains involved in the DNA damage response. We have identified an expanded and conserved ∼100-residue N-terminal region of Dbf4p that includes motif N but is capable of encoding a single BRCT-like domain. Dbf4p orthologs diverge from the BRCT motif at the C terminus but may encode a similar secondary structure in this region. We have therefore called this the BRCT and DBF4 similarity (BRDF) motif. The principal role of this Dbf4p motif was in the response to replication fork (RF) arrest; however, it was not required for cell cycle progression, activation of Cdc7p kinase activity, or interaction with the origin recognition complex (ORC) postulated to recruit Cdc7p–Dbf4p to origins. Rad53p likely directly phosphorylated Dbf4p in response to RF arrest and Dbf4p was required for Rad53p abundance. Rad53p and Dbf4p therefore cooperated to coordinate a robust cellular response to RF arrest. PMID:16547092

Distinct effect of zoledronate and clodronate on circulating levels of DKK1 and sclerostin in women with postmenopausal osteoporosis.

PubMed

Gatti, Davide; Viapiana, Ombretta; Idolazzi, Luca; Fracassi, Elena; Ionescu, Claudio; Dartizio, Carmela; Troplini, Sonila; Kunnathully, Vidya; Adami, Silvano; Rossini, Maurizio

2014-10-01

The coupling of bone formation to bone resorption during treatment of postmenopausal osteoporosis with antiresorbers might be related to changes in Wnt/b-catenin signaling. We compared the effects of two bisphosphonate treatments on two Wnt-inhibitors Sclerostin (SOST) and Dickkopf-related protein 1 (DKK1). The study population included 74 women with postmenopausal osteoporosis participating simultaneously in two multicenter, placebo controlled trials. The patients were randomized to: intramuscular clodronate 100mg/week (CLO) (N=36), and yearly intravenous therapy with 5mg zoledronate (ZOL) (N=18) and placebo (N=20). Bone turnover markers (intact N-propeptide of type I collagen [P1NP], C-terminal telopeptide of type I collagen [CTX]) remained unchanged in the placebo group while they significantly decreased during treatment with the two bisphosphonates, versus both placebo and baseline. In CLO treated patients serum DKK1 remained stable over the entire period of observation while serum SOST levels increased significantly after 12months of treatment both versus placebo group (p<0,005), baseline (p<0,001) and ZOL treated group. In the ZOL group, DKK1 levels increased significantly within one month and for the following 6months and it fell back to baseline values at 12months. The second ZOL infusion was again associated with an increase in DKK1 a month later, although to a lesser extent. In conclusion, in this study we have found that the treatment of postmenopausal osteoporosis with intermittent yearly ZOL is associated with transient and declining increases in DKK1 while continuous treatment with CLO, results in a late increase in serum SOST. These preliminary results and further ad hoc studies might contribute to shed light on our understanding of the bone coupling effects taking place during treatment of osteoporosis with different anti-resorbers or with different treatment regimens. Copyright © 2014 Elsevier Inc. All rights reserved.

The N-Terminal Domain of Human DNA Helicase Rtel1 Contains a Redox Active Iron-Sulfur Cluster

PubMed Central

Landry, Aaron P.

2014-01-01

Human telomere length regulator Rtel1 is a superfamily II DNA helicase and is essential for maintaining proper length of telomeres in chromosomes. Here we report that the N-terminal domain of human Rtel1 (RtelN) expressed in Escherichia coli cells produces a protein that contains a redox active iron-sulfur cluster with the redox midpoint potential of −248 ± 10 mV (pH 8.0). The iron-sulfur cluster in RtelN is sensitive to hydrogen peroxide and nitric oxide, indicating that reactive oxygen/nitrogen species may modulate the DNA helicase activity of Rtel1 via modification of its iron-sulfur cluster. Purified RtelN retains a weak binding affinity for the single-stranded (ss) and double-stranded (ds) DNA in vitro. However, modification of the iron-sulfur cluster by hydrogen peroxide or nitric oxide does not significantly affect the DNA binding activity of RtelN, suggesting that the iron-sulfur cluster is not directly involved in the DNA interaction in the N-terminal domain of Rtel1. PMID:25147792

The N-terminal domain of human DNA helicase Rtel1 contains a redox active iron-sulfur cluster.

PubMed

Landry, Aaron P; Ding, Huangen

2014-01-01

Human telomere length regulator Rtel1 is a superfamily II DNA helicase and is essential for maintaining proper length of telomeres in chromosomes. Here we report that the N-terminal domain of human Rtel1 (RtelN) expressed in Escherichia coli cells produces a protein that contains a redox active iron-sulfur cluster with the redox midpoint potential of -248 ± 10 mV (pH 8.0). The iron-sulfur cluster in RtelN is sensitive to hydrogen peroxide and nitric oxide, indicating that reactive oxygen/nitrogen species may modulate the DNA helicase activity of Rtel1 via modification of its iron-sulfur cluster. Purified RtelN retains a weak binding affinity for the single-stranded (ss) and double-stranded (ds) DNA in vitro. However, modification of the iron-sulfur cluster by hydrogen peroxide or nitric oxide does not significantly affect the DNA binding activity of RtelN, suggesting that the iron-sulfur cluster is not directly involved in the DNA interaction in the N-terminal domain of Rtel1.

Optimization of TiNP/Ti Content for Si3N4/42CrMo Joints Brazed With Ag-Cu-Ti+TiNP Composite Filler

NASA Astrophysics Data System (ADS)

Wang, Tianpeng; Zhang, Jie; Liu, Chunfeng

The Si3N4 ceramic was brazed to 42CrMo steel by using TiN particles modified braze, and the proportion of TiNp reinforcement and active element Ti was optimized to improve the joint strength. The brazed joints were examined by means of SEM. and EDS investigations. Microstructural examination showed that TiN+Ti5Si3 reaction layer was adjacent to Si3N4, whereas TiC was formed in 42CrMo/filler reaction layer. The Ag-Cu-Ti brazing alloy showed intimate bonding with TiNp and Cu-Ti intermetallics precipitated in the joint. The strength tests demonstrated that the mechanical properties of joints increased and then decreased by increasing the TiNp content when a low Ti content (6wt.%) was supplied. When the Ti content (>6wt.%) was offered sufficiently, the joint strength decreased firstly and then stayed stable with increasing the TiNp content. The maximum four-point bending strength (221 MPa) was obtained when the contents of TiNp and Ti were 10vol.% and 6wt.%, respectively.

N-terminal pro-brain natriuretic peptide in acute Kawasaki disease correlates with coronary artery involvement.

PubMed

Adjagba, Philippe M; Desjardins, Laurent; Fournier, Anne; Spigelblatt, Linda; Montigny, Martine; Dahdah, Nagib

2015-10-01

We have lately documented the importance of N-terminal pro-brain natriuretic peptide in aiding the diagnosis of Kawasaki disease. We sought to investigate the potential value of N-terminal pro-brain natriuretic peptide pertaining to the prediction of coronary artery dilatation (Z-score>2.5) and/or of resistance to intravenous immunoglobulin therapy. We hypothesised that increased serum N-terminal pro-brain natriuretic peptide level correlates with increased coronary artery dilatation and/or resistance to intravenous immunoglobulin. We carried out a prospective study involving newly diagnosed patients treated with 2 g/kg intravenous immunoglobulin within 5-10 days of onset of fever. Echocardiography was performed in all patients at onset, then weekly for 3 weeks, then at month 2, and month 3. Coronary arteries were measured at each visit, and coronary artery Z-score was calculated. All the patients had N-terminal pro-brain natriuretic peptide serum level measured at onset, and the Z-score calculated. There were 109 patients enrolled at 6.58±2.82 days of fever, age 3.79±2.92 years. High N-terminal pro-brain natriuretic peptide level was associated with coronary artery dilatation at onset in 22.2 versus 5.6% for normal N-terminal pro-brain natriuretic peptide levels (odds ratio 4.8 [95% confidence interval 1.05-22.4]; p=0.031). This was predictive of cumulative coronary artery dilatation for the first 3 months (p=0.04-0.02), but not during convalescence at 2-3 months (odds ratio 1.28 [95% confidence interval 0.23-7.3]; p=non-significant). Elevated N-terminal pro-brain natriuretic peptide levels did not predict intravenous immunoglobulin resistance, 15.3 versus 13.5% (p=1). Elevated N-terminal pro-brain natriuretic peptide level correlates with acute coronary artery dilatation in treated Kawasaki disease, but not with intravenous immunoglobulin resistance.

Processing of the precursor of protamine P2 in mouse. Peptide mapping and N-terminal sequence analysis of intermediates.

PubMed Central

Carré-Eusèbe, D; Lederer, F; Lê, K H; Elsevier, S M

1991-01-01

Protamine P2, the major basic chromosomal protein of mouse spermatozoa, is synthesized as a precursor almost twice as long as the mature protein, its extra length arising from an N-terminal extension of 44 amino acid residues. This precursor is integrated into chromatin of spermatids, and the extension is processed during chromatin condensation in the haploid cells. We have studied processing in the mouse and have identified two intermediates generated by proteolytic cleavage of the precursor. H.p.l.c. separated protamine P2 from four other spermatid proteins, including the precursor and three proteins known to possess physiological characteristics expected of processing intermediates. Peptide mapping indicated that all of these proteins were structurally similar. Two major proteins were further purified by PAGE, transferred to poly(vinylidene difluoride) membranes and submitted to automated N-terminal sequence analysis. Both sequences were found within the deduced sequence of the precursor extension. The N-terminus of the larger intermediate, PP2C, was Gly-12, whereas the N-terminus of the smaller, PP2D, was His-21. Both processing sites involved a peptide bond in which the carbonyl function was contributed by an acidic amino acid. Images Fig. 1. Fig. 3. Fig. 4. PMID:1854346

Decorin alleviated chronic hydrocephalus via inhibiting TGF-β1/Smad/CTGF pathway after subarachnoid hemorrhage in rats.

PubMed

Yan, Hui; Chen, Yujie; Li, Lingyong; Jiang, Jiaode; Wu, Guangyong; Zuo, Yuchun; Zhang, John H; Feng, Hua; Yan, Xiaoxin; Liu, Fei

2016-01-01

Chronic hydrocephalus is one of the severe complications after subarachnoid hemorrhage (SAH). However, there is no efficient treatment for the prevention of chronic hydrocephalus, partially due to poor understanding of underlying pathogenesis, subarachnoid fibrosis. Transforming growth factor-β1(TGF-β1) is a potent fibrogenic factor implicated in wide range of fibrotic diseases. To investigate whether decorin, a natural antagonist for TGF-β1, protects against subarachnoid fibrosis and chronic hydrocephalus after SAH, two-hemorrhage-injection SAH model was conducted in 6-week-old rats. Recombinant human decorin(rhDecorin) (30ug/2ul) was administered before blood injection and on the 10th day after SAH. TGF-β1, p-Smad2/3, connective tissue growth factor (CTGF), collagen I and pro-collagen I c-terminal propeptide were assessed via western blotting, enzyme-linked immunosorbent assay, radioimmunoassay and immunofluorescence. And neurobehavioral tests and Morris water maze were employed to evaluate long-term neurological functions after SAH. We found that SAH induced heightened activation of TGF-β1/Smad/CTGF axis, presenting as a two peak response of TGF-β1 in cerebrospinal fluid, elevation of TGF-β1, p-Smad2/3, CTGF, collagen I in brain parenchyma and pro-collagen I c-terminal propeptide in cerebrospinal fluid, and increased lateral ventricle index. rhDecorin treatment effectively inhibited up-regulation of TGF-β1, p-Smad2/3, CTGF, collagen I and pro-collagen I c-terminal propeptide after SAH. Moreover, rhDecorin treatment significantly reduced lateral ventricular index and incidence of chronic hydrocephalus after SAH. Importantly, rhDecorin improved neurocognitive deficits after SAH. In conclusion, rhDecorin suppresses extracellular matrix accumulation and following subarachnoid fibrosis via inhibiting TGF-β1/Smad/CTGF pathway, preventing development of hydrocephalus and attenuating long-term neurocognitive defects after SAH. Copyright © 2015 Elsevier B

Recombinant myostatin (GDF-8) propeptide enhances the repair and regeneration of both muscle and bone in a model of deep penetrant musculoskeletal injury.

PubMed

Hamrick, Mark W; Arounleut, Phonepasong; Kellum, Ethan; Cain, Matthew; Immel, David; Liang, Li-Fang

2010-09-01

Myostatin (GDF-8) is known as a potent inhibitor of muscle growth and development, and myostatin is also expressed early in the fracture healing process. The purpose of this study was to test the hypothesis that a new myostatin inhibitor, a recombinant myostatin propeptide, can enhance the repair and regeneration of both muscle and bone in cases of deep penetrant injury. We used a fibula osteotomy model with associated damage to lateral compartment muscles (fibularis longus and brevis) in mice to test the hypothesis that blocking active myostatin with systemic injections of a recombinant myostatin propeptide would improve muscle and bone repair. Mice were assigned to two treatment groups after undergoing a fibula osteotomy: those receiving either vehicle (saline) or recombinant myostatin propeptide (20 mg/kg). Mice received one injection on the day of surgery, another injection 5 days after surgery, and a third injection 10 days after surgery. Mice were killed 15 days after the osteotomy procedure. Bone repair was assessed using microcomputed tomography (micro-CT) and histologic evaluation of the fracture callus. Muscle healing was assessed using Masson trichrome staining of the injury site, and image analysis was used to quantify the degree of fibrosis and muscle regeneration. Three propeptide injections over a period of 15 days increased body mass by 7% and increased muscle mass by almost 20% (p < 0.001). Micro-CT analysis of the osteotomy site shows that by 15 days postosteotomy, bony callus tissue was observed bridging the osteotomy gap in 80% of the propeptide-treated mice but only 40% of the control (vehicle)-treated mice (p < 0.01). Micro-CT quantification shows that bone volume of the fracture callus was increased by ∼ 30% (p < 0.05) with propeptide treatment, and the increase in bone volume was accompanied by a significant increase in cartilage area (p = 0.01). Propeptide treatment significantly decreased the fraction of fibrous tissue in the wound site

p62/SQSTM1/Sequestosome-1 is an N-recognin of the N-end rule pathway which modulates autophagosome biogenesis.

PubMed

Cha-Molstad, Hyunjoo; Yu, Ji Eun; Feng, Zhiwei; Lee, Su Hyun; Kim, Jung Gi; Yang, Peng; Han, Bitnara; Sung, Ki Woon; Yoo, Young Dong; Hwang, Joonsung; McGuire, Terry; Shim, Sang Mi; Song, Hyun Dong; Ganipisetti, Srinivasrao; Wang, Nuozhou; Jang, Jun Min; Lee, Min Jae; Kim, Seung Jun; Lee, Kyung Ho; Hong, Jin Tae; Ciechanover, Aaron; Mook-Jung, Inhee; Kim, Kwang Pyo; Xie, Xiang-Qun; Kwon, Yong Tae; Kim, Bo Yeon

2017-07-24

Macroautophagy mediates the selective degradation of proteins and non-proteinaceous cellular constituents. Here, we show that the N-end rule pathway modulates macroautophagy. In this mechanism, the autophagic adapter p62/SQSTM1/Sequestosome-1 is an N-recognin that binds type-1 and type-2 N-terminal degrons (N-degrons), including arginine (Nt-Arg). Both types of N-degrons bind its ZZ domain. By employing three-dimensional modeling, we developed synthetic ligands to p62 ZZ domain. The binding of Nt-Arg and synthetic ligands to ZZ domain facilitates disulfide bond-linked aggregation of p62 and p62 interaction with LC3, leading to the delivery of p62 and its cargoes to the autophagosome. Upon binding to its ligand, p62 acts as a modulator of macroautophagy, inducing autophagosome biogenesis. Through these dual functions, cells can activate p62 and induce selective autophagy upon the accumulation of autophagic cargoes. We also propose that p62 mediates the crosstalk between the ubiquitin-proteasome system and autophagy through its binding Nt-Arg and other N-degrons.Soluble misfolded proteins that fail to be degraded by the ubiquitin proteasome system (UPS) are redirected to autophagy via specific adaptors, such as p62. Here the authors show that p62 recognises N-degrons in these proteins, acting as a N-recognin from the proteolytic N-end rule pathway, and targets these cargos to autophagosomal degradation.

Intrathecal substance P augments morphine-induced antinociception: possible relevance in the production of substance P N-terminal fragments.

PubMed

Komatsu, Takaaki; Sasaki, Mika; Sanai, Kengo; Kuwahata, Hikari; Sakurada, Chikai; Tsuzuki, Minoru; Iwata, Yohko; Sakurada, Shinobu; Sakurada, Tsukasa

2009-09-01

The present study sought to examine the mechanism of substance P to modulate the antinociceptive action of intrathecal (i.t.) morphine in paw-licking/biting response evoked by subcutaneous injection of capsaicin into the plantar surface of the hindpaw in mice. The i.t. injection of morphine inhibited capsaicin-induced licking/biting response in a dose-dependent manner. Substance P (25 and 50 pmol) injected i.t. alone did not alter capsaicin-induced nociception, whereas substance P at a higher dose of 100 pmol significantly reduced the capsaicin response. Western blots showed the constitutive expression of endopeptidase-24.11 in the dorsal and ventral parts of lumbar spinal cord of mice. The N-terminal fragment of substance P (1-7), which is known as a major product of substance P by endopeptidase-24.11, was more effective than substance P on capsaicin-induced nociception. Combination treatment with substance P (50 pmol) and morphine at a subthreshold dose enhanced the antinociceptive effect of morphine. The enhanced effect of the combination of substance P with morphine was reduced significantly by co-administration of phosphoramidon, an inhibitor of endopeptidase-24.11. Administration of D-isomer of substance P (1-7), [D-Pro(2), D-Phe(7)]substance P (1-7), an inhibitor of [(3)H] substance P (1-7) binding, or antisera against substance P (1-7) reversed the enhanced antinociceptive effect by co-administration of substance P and morphine. Taken together these data suggest that morphine-induced antinociception may be enhanced through substance P (1-7) formed by the enzymatic degradation of i.t. injected substance P in the spinal cord.

The association between bone turnover markers and kyphosis in community-dwelling older adults.

PubMed

McDaniels-Davidson, Corinne R; Kritz-Silverstein, Donna; Huang, Mei-Hua; Laughlin, Gail A; Johnson, Sarah; Haapalahti, Jouko; Schneider, Diane L; Barrett-Connor, Elizabeth; Kado, Deborah M

2016-12-01

Hyperkyphosis, accentuated curvature of the thoracic spine, is often attributed to osteoporosis, yet its underlying pathophysiology is not well understood. Bone turnover markers (BTM) reflect the dynamic process of bone formation and resorption. This study examined the association between serum BTM levels and kyphosis in community-dwelling older adults. Between 2003 and 2006, 760 men and women in the Rancho Bernardo Study age 60 and older had blood drawn and kyphosis measured. Fasting serum was assayed for N-telopeptide (NTX) and procollagen type 1 n-terminal propeptide (P1NP), markers of bone resorption and formation, respectively. Participants requiring two or more 1.7 cm blocks under their head to achieve a neutral supine position were classified as having accentuated kyphosis. Analyses were stratified by sex and use of estrogen therapy (ET). Odds of accentuated kyphosis were calculated for each standard deviation increase in log-transformed BTM. Mean age was 75 years. Overall, 51% of 341 non-ET using women, 41% of 111 ET-using women, and 75% of 308 men had accentuated kyphosis. In adjusted models, higher P1NP and NTX were associated with decreased odds of accentuated kyphosis in non-ET using women (P1NP: OR = 0.78 [95% CI, 0.58-0.92]; NTX: OR = 0.68 [95% CI, 0.54-0.86]), but not in men or ET-using women ( p  > 0.05). The selective association of higher bone turnover with reduced odds of accentuated kyphosis in non-ET using women suggests that elevated BTM were associated with a lower likelihood of hyperkyphosis only in the low estrogen/high BTM environment characteristic of postmenopausal women who are not using ET.

Strain differences in the neural, behavioral, and molecular correlates of sweet and salty taste in naive, ethanol- and sucrose-exposed P and NP rats

PubMed Central

Coleman, Jamison; Williams, Ashley; Phan, Tam-Hao T.; Mummalaneni, Shobha; Melone, Pamela; Ren, ZuoJun; Zhou, Huiping; Mahavadi, Sunila; Murthy, Karnam S.; Katsumata, Tadayoshi; DeSimone, John A.

2011-01-01

Strain differences between naive, sucrose- and ethanol-exposed alcohol-preferring (P) and alcohol-nonpreferring (NP) rats were investigated in their consumption of ethanol, sucrose, and NaCl; chorda tympani (CT) nerve responses to sweet and salty stimuli; and gene expression in the anterior tongue of T1R3 and TRPV1/TRPV1t. Preference for 5% ethanol and 10% sucrose, CT responses to sweet stimuli, and T1R3 expression were greater in naive P rats than NP rats. The enhancement of the CT response to 0.5 M sucrose in the presence of varying ethanol concentrations (0.5–40%) in naive P rats was higher and shifted to lower ethanol concentrations than NP rats. Chronic ingestion of 5% sucrose or 5% ethanol decreased T1R3 mRNA in NP and P rats. Naive P rats also demonstrated bigger CT responses to NaCl+benzamil and greater TRPV1/TRPV1t expression. TRPV1t agonists produced biphasic effects on NaCl+benzamil CT responses, enhancing the response at low concentrations and inhibiting it at high concentrations. The concentration of a TRPV1/TRPV1t agonist (Maillard reacted peptides conjugated with galacturonic acid) that produced a maximum enhancement in the NaCl+benzamil CT response induced a decrease in NaCl intake and preference in P rats. In naive P rats and NP rats exposed to 5% ethanol in a no-choice paradigm, the biphasic TRPV1t agonist vs. NaCl+benzamil CT response profiles were higher and shifted to lower agonist concentrations than in naive NP rats. TRPV1/TRPV1t mRNA expression increased in NP rats but not in P rats exposed to 5% ethanol in a no-choice paradigm. We conclude that P and NP rats differ in T1R3 and TRPV1/TRPV1t expression and neural and behavioral responses to sweet and salty stimuli and to chronic sucrose and ethanol exposure. PMID:21849614

Strain differences in the neural, behavioral, and molecular correlates of sweet and salty taste in naive, ethanol- and sucrose-exposed P and NP rats.

PubMed

Coleman, Jamison; Williams, Ashley; Phan, Tam-Hao T; Mummalaneni, Shobha; Melone, Pamela; Ren, Zuojun; Zhou, Huiping; Mahavadi, Sunila; Murthy, Karnam S; Katsumata, Tadayoshi; DeSimone, John A; Lyall, Vijay

2011-11-01

Strain differences between naive, sucrose- and ethanol-exposed alcohol-preferring (P) and alcohol-nonpreferring (NP) rats were investigated in their consumption of ethanol, sucrose, and NaCl; chorda tympani (CT) nerve responses to sweet and salty stimuli; and gene expression in the anterior tongue of T1R3 and TRPV1/TRPV1t. Preference for 5% ethanol and 10% sucrose, CT responses to sweet stimuli, and T1R3 expression were greater in naive P rats than NP rats. The enhancement of the CT response to 0.5 M sucrose in the presence of varying ethanol concentrations (0.5-40%) in naive P rats was higher and shifted to lower ethanol concentrations than NP rats. Chronic ingestion of 5% sucrose or 5% ethanol decreased T1R3 mRNA in NP and P rats. Naive P rats also demonstrated bigger CT responses to NaCl+benzamil and greater TRPV1/TRPV1t expression. TRPV1t agonists produced biphasic effects on NaCl+benzamil CT responses, enhancing the response at low concentrations and inhibiting it at high concentrations. The concentration of a TRPV1/TRPV1t agonist (Maillard reacted peptides conjugated with galacturonic acid) that produced a maximum enhancement in the NaCl+benzamil CT response induced a decrease in NaCl intake and preference in P rats. In naive P rats and NP rats exposed to 5% ethanol in a no-choice paradigm, the biphasic TRPV1t agonist vs. NaCl+benzamil CT response profiles were higher and shifted to lower agonist concentrations than in naive NP rats. TRPV1/TRPV1t mRNA expression increased in NP rats but not in P rats exposed to 5% ethanol in a no-choice paradigm. We conclude that P and NP rats differ in T1R3 and TRPV1/TRPV1t expression and neural and behavioral responses to sweet and salty stimuli and to chronic sucrose and ethanol exposure.

[C, N, P, K Stoichiometric Characteristic of Leaves, Root and Soil in Different Abandoned Years in Loess Plateau].

PubMed

Zhang, Hai-dong; Ru, Hai-li; Jiao, Feng; Xue, Chao-yu; Guo, Mei-li

2016-03-15

The research of plant ecological stoichiometry characteristics, nutrients distribution and their changes is of great significance to explain the response and adaptation of plants to environmental change. Leaves, root and soil from eight different abandoned years in Yanhe River basin were selected to study the content, characteristic ratio and distribution of carbon ( C) , nitrogen (N) , phosphorus (P), potassium (K). The results showed that the C, N, P, K contents of plant leaves were 444.21, 22.34, 1.49, 14.66 mg · g⁻¹ respectively, the C/N, C/P, C/K, N/P ratios of plant leaves were 21.86, 424.72, 39.82, 20.27 respectively; the C, N, P, K contents of root were 285.16, 5.79, 0.27, 6.07 mg · g⁻¹ respectively, the C/N, C/P, C/K, N/P ratios of root were .60. 56, 1019.33, 46.55, 21.36 respectively; the C, N, P, K contents of soil were 2.28, 0.18, 0.28, 4.33 mg · g⁻¹ respectively, the C/N, C/P, C/K, N/P ratios of soil were 16.43, 8.40, 0.54, 0.66 respectively. During the abandoned year of 1-35, C content of leaves increased, N content increased and then declined, P content declined overall, K content declined and then increased. The C/N, C/P, C/K, N/P ratios of plant leaves showed a rising trend overall. The changing pattern of root was different from that of leaves. Along with the increasing rehabilitation age, C and N contents of soil increased, P content changed as arc-sin function, K content changed as parabola, C/N decreased, C/P, C/K, N/P increased. With the increase of Abandoned Years, the ratio of C, P, K contents in leaves and root decreased, the ratio of C, N, P contents in leaves and soil decreased, the ratio of C, N contents in root and soil decreased. Corresponding relationship and its intension between different abandoned years and plant nutrient limit status and its allocation pattern were different.

The determination of transport parameters of minority carriers in n-p junctions by means of an electron microscope - Critique of recent developments

NASA Technical Reports Server (NTRS)

Von Roos, O.

1980-01-01

It has recently been shown that amplitude modulated electron beams provide a novel means for the determination of minority carrier lifetimes, diffusion lengths, etc., in n-p junctions. In this paper it is shown that: (1) a recently published analysis based on a cylindrically symmetric configuration is incorrect, (2) the correct approach leads to a system of dual integral equations for which the formal solution is given, (3) in general, the short circuit current can only be determined by means of extensive computer calculations except in the case of large front surface recombination velocities, and (4) the difficulties encountered with cylindrically symmetric configurations (circular ohmic contacts and the like) are completely avoided with a choice of a planar geometry since simple closed form expressions for the short circuit current are readily available in this case.

The antibiotic cyclomarin blocks arginine-phosphate-induced millisecond dynamics in the N-terminal domain of ClpC1 from Mycobacterium tuberculosis.

PubMed

Weinhäupl, Katharina; Brennich, Martha; Kazmaier, Uli; Lelievre, Joel; Ballell, Lluis; Goldberg, Alfred; Schanda, Paul; Fraga, Hugo

2018-06-01

Mycobacterium tuberculosis can remain dormant in the host, an ability that explains the failure of many current tuberculosis treatments. Recently, the natural products cyclomarin, ecumicin, and lassomycin have been shown to efficiently kill Mycobacterium tuberculosis persisters. Their target is the N-terminal domain of the hexameric AAA+ ATPase ClpC1, which recognizes, unfolds, and translocates protein substrates, such as proteins containing phosphorylated arginine residues, to the ClpP1P2 protease for degradation. Surprisingly, these antibiotics do not inhibit ClpC1 ATPase activity, and how they cause cell death is still unclear. Here, using NMR and small-angle X-ray scattering, we demonstrate that arginine-phosphate binding to the ClpC1 N-terminal domain induces millisecond dynamics. We show that these dynamics are caused by conformational changes and do not result from unfolding or oligomerization of this domain. Cyclomarin binding to this domain specifically blocked these N-terminal dynamics. On the basis of these results, we propose a mechanism of action involving cyclomarin-induced restriction of ClpC1 dynamics, which modulates the chaperone enzymatic activity leading eventually to cell death. © 2018 Weinhäupl et al.

Human IGF-I propeptide A promotes articular chondrocyte biosynthesis and employs glycosylation-dependent heparin binding.

PubMed

Shi, Shuiliang; Kelly, Brian J; Wang, Congrong; Klingler, Ken; Chan, Albert; Eckert, George J; Trippel, Stephen B

2018-03-01

Insulin-like growth factor I (IGF-I) is a key regulator of chondrogenesis, but its therapeutic application to articular cartilage damage is limited by rapid elimination from the repair site. The human IGF-I gene gives rise to three IGF-I propeptides (proIGF-IA, proIGF-IB and proIGF-IC) that are cleaved to create mature IGF-I. In this study, we elucidate the processing of IGF-I precursors by articular chondrocytes, and test the hypotheses that proIGF-I isoforms bind to heparin and regulate articular chondrocyte biosynthesis. Human IGF-I propeptides and mutants were overexpressed in bovine articular chondrocytes. IGF-I products were characterized by ELISA, western blot and FPLC using a heparin column. The biosynthetic activity of IGF-I products on articular chondrocytes was assayed for DNA and glycosaminoglycan that the cells produced. Secreted IGF-I propeptides stimulated articular chondrocyte biosynthetic activity to the same degree as mature IGF-I. Of the three IGF-I propeptides, only one, proIGF-IA, strongly bound to heparin. Interestingly, heparin binding of proIGF-IA depended on N-glycosylation at Asn92 in the EA peptide. To our knowledge, this is the first demonstration that N-glycosylation determines the binding of a heparin-binding protein to heparin. The biosynthetic and heparin binding abilities of proIGF-IA, coupled with its generation of IGF-I, suggest that proIGF-IA may have therapeutic value for articular cartilage repair. These data identify human pro-insulin-like growth factor IA as a bifunctional protein. Its combined ability to bind heparin and augment chondrocyte biosynthesis makes it a promising therapeutic agent for cartilage damage due to trauma and osteoarthritis. Copyright © 2017 Elsevier B.V. All rights reserved.

Covariant spectator theory of np scattering: Deuteron quadrupole moment

DOE PAGES

Gross, Franz

2015-01-26

The deuteron quadrupole moment is calculated using two CST model wave functions obtained from the 2007 high precision fits to np scattering data. Included in the calculation are a new class of isoscalar np interaction currents automatically generated by the nuclear force model used in these fits. The prediction for model WJC-1, with larger relativistic P-state components, is 2.5% smaller that the experiential result, in common with the inability of models prior to 2014 to predict this important quantity. However, model WJC-2, with very small P-state components, gives agreement to better than 1%, similar to the results obtained recently frommore » XEFT predictions to order N 3LO.« less

Women with previous stress fractures show reduced bone material strength

PubMed Central

Duarte Sosa, Daysi; Fink Eriksen, Erik

2016-01-01

Background and purpose — Bone fragility is determined by bone mass, bone architecture, and the material properties of bone. Microindentation has been introduced as a measurement method that reflects bone material properties. The pathogenesis of underlying stress fractures, in particular the role of impaired bone material properties, is still poorly understood. Based on the hypothesis that impaired bone material strength might play a role in the development of stress fractures, we used microindentation in patients with stress fractures and in controls. Patients and methods — We measured bone material strength index (BMSi) by microindentation in 30 women with previous stress fractures and in 30 normal controls. Bone mineral density by DXA and levels of the bone markers C-terminal cross-linking telopeptide of type-1 collagen (CTX) and N-terminal propeptide of type-1 procollagen (P1NP) were also determined. Results — Mean BMSi in stress fracture patients was significantly lower than in the controls (SD 72 (8.7) vs. 77 (7.2); p = 0.02). The fracture subjects also had a significantly lower mean bone mineral density (BMD) than the controls (0.9 (0.02) vs. 1.0 (0.06); p = 0.03). Bone turnover—as reflected in serum levels of the bone marker CTX—was similar in both groups, while P1NP levels were significantly higher in the women with stress fractures (55 μg/L vs. 42 μg/L; p = 0.03). There was no correlation between BMSi and BMD or bone turnover. Interpretation — BMSi was inferior in patients with previous stress fracture, but was unrelated to BMD and bone turnover. The lower values of BMSi in patients with previous stress fracture combined with a lower BMD may contribute to the increased propensity to develop stress fractures in these patients. PMID:27321443

Investigation of the system ThO 2-NpO 2-P 2O 5. Solid solutions of thorium-neptunium (IV) phosphate-diphosphate

NASA Astrophysics Data System (ADS)

Dacheux, N.; Thomas, A. C.; Brandel, V.; Genet, M.

1998-11-01

Considering that phosphate matrices could be potential candidates for the immobilization of actinides or for the final disposal of the excess plutonium from dismantled nuclear weapons, the chemistry of thorium phosphates has been re-examined. In the ThO 2-P 2O 5 system, the thorium phosphate-diphosphate Th 4(PO 4) 4P 2O 7 (TPD) can be synthesized by wet and dry chemical processes. The substitution of thorium by other tetravalent actinides like uranium or plutonium can be obtained for 0 < x < 3.0 and 0 < x < 1.63, respectively. In this work, we report the chemical conditions of synthesis of thorium-neptunium (IV) phosphate-diphosphate solid solutions Th 4- xNp x(PO 4) 4P 2O 7 (TNPD) with 0 < x < 1.6 from a mixture of thorium and neptunium (IV) nitrates and concentrated phosphoric acid. From the variation of the cell parameters and volume, the maximum substitution of Th 4+ by Np 4+ in the TPD structure is evaluated to 2.08 (which corresponds to about 52 mol% of thorium replaced by neptunium (IV)). The field of existence of solid solutions Th 4- xU- xNp- xPuU xUNp xNpPu xPu(PO 4)4P 2O 7 has been calculated. These solid solutions should be synthesized for 5 xU+7 xNp+9 xPu⩽15. In the NpO 2-P 2O 5 system, the unit cell parameters of Np 2O(PO 4) 2 were refined by analogy with U 2O(PO 4) 2 which crystallographic data have been published recently. For Np 2O(PO 4) 2 the unit cell is orthorhombic with the following cell parameters: a=7.033(2) Å, b=9.024(3) Å, c=12.587(6) Å and V=799(1) Å 3. The unit cell parameter obtained for α-NpP 2O 7 ( a=8.586(1) Å) is in good agreement with those already reported in literature.

NpPDR1, a pleiotropic drug resistance-type ATP-binding cassette transporter from Nicotiana plumbaginifolia, plays a major role in plant pathogen defense.

PubMed

Stukkens, Yvan; Bultreys, Alain; Grec, Sébastien; Trombik, Tomasz; Vanham, Delphine; Boutry, Marc

2005-09-01

Nicotiana plumbaginifolia NpPDR1, a plasma membrane pleiotropic drug resistance-type ATP-binding cassette transporter formerly named NpABC1, has been suggested to transport the diterpene sclareol, an antifungal compound. However, direct evidence for a role of pleiotropic drug resistance transporters in the plant defense is still lacking. In situ immunolocalization and histochemical analysis using the gusA reporter gene showed that NpPDR1 was constitutively expressed in the whole root, in the leaf glandular trichomes, and in the flower petals. However, NpPDR1 expression was induced in the whole leaf following infection with the fungus Botrytis cinerea, and the bacteria Pseudomonas syringae pv tabaci, Pseudomonas fluorescens, and Pseudomonas marginalis pv marginalis, which do not induce a hypersensitive response in N. plumbaginifolia, whereas a weaker response was observed using P. syringae pv syringae, which does induce a hypersensitive response. Induced NpPDR1 expression was more associated with the jasmonic acid than the salicylic acid signaling pathway. These data suggest that NpPDR1 is involved in both constitutive and jasmonic acid-dependent induced defense. Transgenic plants in which NpPDR1 expression was prevented by RNA interference showed increased sensitivity to sclareol and reduced resistance to B. cinerea. These data show that NpPDR1 is involved in pathogen resistance and thus demonstrate a new role for the ATP-binding cassette transporter family.

Experimental and theoretical studies of the npσ1Σu+ and npπ1 Πu+ (n ⩾ 4,N‧ = 1 -6) states of D2: Energies, natural widths, absorption line intensities, and dynamics

NASA Astrophysics Data System (ADS)

Glass-Maujean, M.; Jungen, Ch.; Vasserot, A. M.; Schmoranzer, H.; Knie, A.; Kübler, S.; Ehresmann, A.; Ubachs, W.

2017-08-01

Over a thousand spectral lines in the photoexcitation spectrum of molecular deuterium (D2) to np1 Σu+ and 1Πu+ Rydberg levels (n ⩾ 4) were measured for rotational levels N‧ = 1 -6 in the 117 000-137 000 cm-1 spectral range by two different types of experiments at two synchrotron radiation sources: a vacuum ultraviolet (VUV) Fourier-transform (FT) spectrometer at SOLEIL, Paris and a 10 m-normal-incidence monochromator (NIM) at BESSY II, Berlin. The experimental energies, the absorption cross sections, Einstein A-coefficients, and line widths are compared with ab initio multi-channel quantum defect (MQDT) calculations for these levels. More than 350 R(0) or P(2) lines were assigned, some 280 R(1) or P(3) lines, some 270 R(2) or P(4) lines, over 100 R(3) or P(5) lines, over 90 R(4) lines, and 24 R(5) lines to extract information on the N‧ = 1 -6 excited levels. Transition energies were determined up to excitation energies of 137 000 cm-1 above the ground state, thereby extending earlier work by various authors and considerably improving the spectral accuracy (< 0.1 cm-1), leading to several reassignments. The absorption and the dissociation, ionization and fluorescence excitation cross sections from the NIM experiment are measured on absolute scale and are used to calibrate intensities in the VUV-FT spectra. The overall agreement between experiment and first principles calculations, without adjustable parameters, is excellent in view of the multi-state interferences treated within the MQDT-framework: For the low N‧ values the averaged deviations between those observed in the FT-SOLEIL spectra and those calculated with MQDT are ∼ 0.1 cm-1 with a spread of ∼ 0.5 cm-1. The line intensities in terms of Einstein coefficients are well represented in the MQDT-framework, as are the level widths representing the lifetimes associated with the sum of the three decay channels. These line intensities follow, in general, the 1 /n3 scaling behavior as characteristic in

Serum N-propeptide of collagen IIA (PIIANP) as a marker of radiographic osteoarthritis burden.

PubMed

Daghestani, Hikmat N; Jordan, Joanne M; Renner, Jordan B; Doherty, Michael; Wilson, A Gerry; Kraus, Virginia B

2017-01-01

Cartilage homeostasis relies on a balance of catabolism and anabolism of cartilage matrix. Our goal was to evaluate the burden of radiographic osteoarthritis and serum levels of type IIA procollagen amino terminal propeptide (sPIIANP), a biomarker representing type II collagen synthesis, in osteoarthritis. OA burden was quantified on the basis of radiographic features as total joint faces with an osteophyte, joint space narrowing, or in the spine, disc space narrowing. sPIIANP was measured in 1,235 participants from the Genetics of Generalized Osteoarthritis study using a competitive enzyme-linked immunosorbent assay. Separate multivariable linear regression models, adjusted for age, sex, and body mass index and additionally for ipsilateral osteophytes or joint/disc space narrowing, were used to assess the independent association of sPIIANP with osteophytes and with joint/disc space narrowing burden in knees, hips, hands and spine, individually and together. After full adjustment, sPIIANP was significantly associated with a lesser burden of hip joint space narrowing and knee osteophytes. sPIIANP was associated with a lesser burden of hand joint space narrowing but a greater burden of hand osteophytes; these results were only evident upon adjustment for osteoarthritic features in all other joints. There were no associations of sPIIANP and features of spine osteoarthritis. Higher cartilage collagen synthesis, as reflected in systemic PIIANP concentrations, was associated with lesser burden of osteoarthritic features in lower extremity joints (knees and hips), even accounting for osteoarthritis burden in hands and spine, age, sex and body mass index. These results suggest that pro-anabolic agents may be appropriate for early treatment to prevent severe lower extremity large joint osteoarthritis.

Unusual ordering in c-NpPd3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gofryk, Krzysztof

2010-01-01

NpPd{sub 3} exhibits two crystal structures. At room temperature, the equilibrium structure is the dhcp TiNi{sub 3}-type, but rapid cooling from melt produces the cubic AuCu{sub 3}-type structure. In both cases, the Np-Np distance is 4.1 {angstrom}, so that the Np ions are expected to be localized. Both phases of NpPd{sub 3} were first studied at the ANL in the early 1970s. Nellis et al measured the magnetic susceptibility and the electrical resistivity of cubic NpPd{sub 3}, and found evidence of magnetic ordering setting in below T{sub N} = 54 K. The magnetic order in this phase was confirmed bymore » Moessbauer and neutron studies. The neutron data revealed several magnetic Bragg peaks with an ordering wave-vector of (1/2,1/2, 1/2). In contrast, no evidence for any long-range magnetic ordering was found for dhcp NpPd{sub 3}, despite the presence of an anomaly at 30 K in the bulk magnetic data. Our recent measurements of the magnetic (magnetization, susceptibility), thermal (heat capacity) and transport (electrical resistivity, magnetoresistivity, thermopower and Hall effect) properties of cubic NpPd{sub 3} indicated highly unusual nature of the magnetic ordering. At T{sub N}, the specific heat exhibits an extremely large peak [as large as 1000 J/(mol K)] and the magnetic susceptibility shows a clear jump. The transport properties of c-NpPd{sub 3} indicate a dramatic Fermi-surface reconstruction at T{sub N}, which shows up as pronounced anomalies at this temperature in the electrical resistivity, the magnetoresistivity, the Seebeck coefficient and the Hall coefficient.« less

The N-terminus and Phe52 residue of LC3 recruit p62/SQSTM1 into autophagosomes.

PubMed

Shvets, Elena; Fass, Ephraim; Scherz-Shouval, Ruthie; Elazar, Zvulun

2008-08-15

LC3 belongs to a novel ubiquitin-like protein family that is involved in different intracellular trafficking processes, including autophagy. All members of this family share a unique three-dimensional structure composed of a C-terminal ubiquitin core and two N-terminal alpha-helices. Here, we focus on the specific contribution of these regions to autophagy induced by amino acid deprivation. We show that the ubiquitin core by itself is sufficient for LC3 processing through the conjugation machinery and for its consequent targeting to the autophagosomal membrane. The N-terminal region was found to be important for interaction between LC3 and p62/SQSTM1 (hereafter termed p62). This interaction is dependent on the first 10 amino acids of LC3 and on specific residues located within the ubiquitin core. Knockdown of LC3 isoforms and overexpression of LC3 mutants that fail to interact with p62 blocked the incorporation of p62 into autophagosomes. The accumulation of p62 was accompanied by elevated levels of polyubiquitylated detergent-insoluble structures. p62, however, is not required for LC3 lipidation, autophagosome formation and targeting to lysosomes. Our results support the proposal that LC3 is responsible for recruiting p62 into autophagosomes, a process mediated by phenylalanine 52, located within the ubiquitin core, and the N-terminal region of the protein.

Naringin protects against bone loss in steroid-treated inflammatory bowel disease in a rat model.

PubMed

Li, Chengli; Zhang, Jun; Lv, Fang; Ge, Xingtao; Li, Gang

2018-07-15

We observed the effects of naringin on bone loss in glucocorticoid-treated inflammatory bowel disease (IBD) in a rat model. The IBD model was established in Sprague-Dawley rats by administering 5.0% dextran sodium sulfate. Dexamethasone (DEX) and naringin were given at the second week. Blood, colon and bone samples were collected for biomarker assay, histological analysis or microCT analysis. Superoxide dismutase, catalase and malonaldehyde were measured in bone. A significant decrease of procollagen type 1 N-terminal propeptide (P1NP) level was observed in DEX-treated IBD groups compared with the control (p < 0.05). P1NP levels were dose-dependently increased in the presence of naringin intervention. Bone loss and decreased bone biomechanical properties were observed in DEX-treated IBD rats compared with control rats (p < 0.01). Naringin intervention protected against bone loss and decreased bone biomechanical properties. Bone formation related gene mRNA expressions were significantly decreased in DEX-treated IBD rats compared with control rats. Naringin administration reversed the down-regulation of the expressions of those genes. Naringin treatment reduced the oxidative stress in bone from DEX-treated IBD rats. Our data indicated that naringin may have great potential for the treatment of bone loss in glucocorticoid-treated IBD patients via blocking oxidative stress and promoting bone formation. Copyright © 2018 Elsevier Inc. All rights reserved.

Carbon, Nitrogen and Phosphorus Accumulation and Partitioning, and C:N:P Stoichiometry in Late-Season Rice under Different Water and Nitrogen Managements

PubMed Central

Ye, Yushi; Liang, Xinqiang; Chen, Yingxu; Li, Liang; Ji, Yuanjing; Zhu, Chunyan

2014-01-01

Water and nitrogen availability plays an important role in the biogeochemical cycles of essential elements, such as carbon (C), nitrogen (N) and phosphorus (P), in agricultural ecosystems. In this study, we investigated the seasonal changes of C, N and P concentrations, accumulation, partitioning, and C:N:P stoichiometric ratios in different plant tissues (root, stem-leaf, and panicle) of late-season rice under two irrigation regimes (continuous flooding, CF; alternate wetting and drying, AWD) and four N managements (control, N0; conventional urea at 240 kg N ha−1, UREA; controlled-release bulk blending fertilizer at 240 kg N ha−1, BBF; polymer-coated urea at 240 kg N ha−1, PCU). We found that water and N treatments had remarkable effects on the measured parameters in different plant tissues after transplanting, but the water and N interactions had insignificant effects. Tissue C:N, N:P and C:P ratios ranged from 14.6 to 52.1, 3.1 to 7.8, and 76.9 to 254.3 over the rice growing seasons, respectively. The root and stem-leaf C:N:P and panicle C:N ratios showed overall uptrends with a peak at harvest whereas the panicle N:P and C:P ratios decreased from filling to harvest. The AWD treatment did not affect the concentrations and accumulation of tissue C and N, but greatly decreased those of P, resulting in enhanced N:P and C:P ratios. N fertilization significantly increased tissue N concentration, slightly enhanced tissue P concentration, but did not affect tissue C concentration, leading to a significant increase in tissue N:P ratio but a decrease in C:N and C:P ratios. Our results suggested that the growth of rice in the Taihu Lake region was co-limited by N and P. These findings broadened our understanding of the responses of plant C:N:P stoichiometry to simultaneous water and N managements in subtropical high-yielding rice systems. PMID:24992006

Thalassemic osteopathy: a new marker of bone deposition.

PubMed

Baldini, M; Forti, S; Orsatti, A; Marcon, A; Ulivieri, F M; Airaghi, L; Zanaboni, L; Cappellini, M D

2014-01-01

Osteopathy represents a prominent cause of morbidity in patients with beta-thalassemia major (TM) and manifests as osteopenia/osteoporosis. Biochemical turnover markers (BTMs) are considered a useful, non-invasive tool for the clinical follow-up of osteoporotic patients; they can provide a dynamic view of the remodeling process and give information on the metabolic activity of bone tissue as well as on the pathogenesis of bone loss. The amino-terminal pro-peptide of type I procollagen (P1NP) is a recently introduced marker that is considered the most sensitive index of bone formation. Although demonstrated in several categories of patients with bone disease, there is little information on the clinical usefulness of this bone formation index in thalassemic patients. We evaluated the P1NP levels of 53 adult patients with b-thalassemia major (21 males and 32 females, mean age 34.5 ± 5.7, range 22-46 years) and associated osteopathy. We investigated the correlation between P1NP and bone condition as examined by dual X-ray photon absorptiometry and with BTMs expressing bone resorption and bone mineralization (carboxyterminal collagen cross-linked (CTX) terminal regions of type I collagen and osteocalcin, respectively). P1NP serum levels were correlated with CTX levels (r=0.545, p<0.001); the results were unchanged when males and females, as well as osteoporotic and osteopenic subgroups, were considered separately. No correlation was demonstrated neither between OC and CTX (r=0.17, p=ns), nor between P1NP and OC levels (r=0.11, p=ns). No correlation was demonstrated among the P1NP/CTX ratio and age, OC or densitometric values and no difference was found in the same ratio between osteopenic (0.19 ± 0.16) and osteoporotic (0.15 ± 0.14) patients. Similar results were obtained for the OC/CTX ratio, as it was not correlated with age, P1NP or densitometric values. This is the first report of circulating P1NP in patients with TM-associated osteoporosis. P1NP and CTX assays

Skn-1a/Oct-11 and {Delta}Np63{alpha} exert antagonizing effects on human keratin expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lena, Anna Maria; Cipollone, Rita; Amelio, Ivano

2010-10-29

Research highlights: {yields} Skn-1a markedly downregulates {Delta}Np63-driven K14 expression. {yields} {Delta}Np63 inhibits Skn-1a-mediated K10 expression. {yields} {Delta}Np63, mutated in SAM domain, is less effecting in K10 downregulation. {yields} Immunolocalization in human skin of the two transcription factors is partially overlapping. {yields} The antagonistic effects of Skn-1a and p63 is through competition for overlapping responsive elements or through an indirect interaction. -- Abstract: The formation of a stratified epidermis requires a carefully controlled balance between keratinocyte proliferation and differentiation. Here, we report the reciprocal effect on keratin expression of {Delta}Np63, pivotal in normal epidermal morphogenesis and maintenance, and Skn-1a/Oct-11, a POUmore » transcription factor that triggers and regulates the differentiation of keratinocytes. The expression of Skn-1a markedly downregulated {Delta}Np63-driven K14 expression in luciferase reporter assays. The extent of downregulation was comparable to the inhibition of Skn-1a-mediated K10 expression upon expression of {Delta}Np63. {Delta}Np63, mutated in the protein-protein interaction domain (SAM domain; mutated in human ectodermal dysplasia syndrome), was significantly less effecting in downregulating K10, raising the possibility of a direct interaction among Skn-1a and {Delta}Np63. Immunolocalization in human skin biopsies revealed that the expression of the two transcription factors is partially overlapping. Co-immunoprecipitation experiments did not, however, demonstrate a direct interaction between {Delta}Np63 and Skn-1a, suggesting that the antagonistic effects of Skn-1a and p63 on keratin promoter transactivation is probably through competition for overlapping binding sites on target gene promoter or through an indirect interaction.« less

Synthesis of potent agonists of substance P by replacement of Met11 with Glu(OBzl) and N-terminal glutamine with Glp of the C-terminal hexapeptide and heptapeptide of substance P.

PubMed

Stavropoulos, G; Karagiannis, K; Anagnostides, S; Ministrouski, I; Selinger, Z; Chorev, M

1995-06-01

The analogues [Glp6,Glu(OBzl)11]SP(6-11) and [Glp5,Glu(OBzl)11]SP(5-11) of the C-terminal hexapeptide and heptapeptide of Substance P have been synthesized by conventional solution methods. In each analogue the N-terminal glutamine has been replaced by pyroglutamic acid, while the COOCH2C6H5 ester group has replaced the SCH3 group of the Met11 side chain. The in vitro activity of both analogues has been determined on three biological preparations: guinea pig ileum (GPI), rat vas deferens (RVD) and rat portal vein (RPV). The results showed that both analogues are highly potent and selective agonists on GPI through the NK-1 receptor. They are more potent than SP itself, with 1.54 and 1.25 respective values of relative potency on GPI. Their selectivity has been studied by utilizing atropine-treated guinea pig ileum (GPI+At). The analogues showed low activity on RVD and RPV tissues, which represent NK-2 and NK-3 monoreceptor assay, respectively.

The amino terminal end determines the stability and assembling capacity of eukaryotic ribosomal stalk proteins P1 and P2.

PubMed

Camargo, Hendricka; Nusspaumer, Gretel; Abia, David; Briceño, Verónica; Remacha, Miguel; Ballesta, Juan P G

2011-05-01

The eukaryotic ribosomal proteins P1 and P2 bind to protein P0 through their N-terminal domain to form the essential ribosomal stalk. A mutational analysis points to amino acids at positions 2 and 3 as determinants for the drastic difference of Saccharomyces cerevisiae P1 and P2 half-life, and suggest different degradation mechanisms for each protein type. Moreover, the capacity to form P1/P2 heterodimers is drastically affected by mutations in the P2β four initial amino acids, while these mutations have no effect on P1β. Binding of P2β and, to a lesser extent, P1β to the ribosome is also seriously affected showing the high relevance of the amino acids in the first turn of the NTD α-helix 1 for the stalk assembly. The negative effect of some mutations on ribosome binding can be reversed by the presence of the second P1/P2 couple in the ribosome, indicating a stabilizing structural influence between the two heterodimers. Unexpectedly, some mutations totally abolish heterodimer formation but allow significant ribosome binding and, therefore, a previous P1 and P2 association seems not to be an absolute requirement for stalk assembly. Homology modeling of the protein complexes suggests that the mutated residues can affect the overall protein conformation. © The Author(s) 2011. Published by Oxford University Press.

War Termination

DTIC Science & Technology

2010-06-21

Hills seemed especially urgent. An economic depression hit the country in 1873 followed by the discovery of gold in the Black Hills the next year...University of Oklahoma Press, 1994). 84 Endnotes 1. John S. Gray, “ Centennial Campaign: The Sioux War of 1876,” (n.p.: The Old Army Press, 1976) p. 211

Perinatal collagen turnover markers in intrauterine growth restriction.

PubMed

Gourgiotis, Demetrios; Briana, Despina D; Georgiadis, Anestis; Boutsikou, Maria; Baka, Stavroula; Marmarinos, Antonios; Hassiakos, Demetrios; Malamitsi-Puchner, Ariadne

2012-09-01

To investigate bone and connective tissue collagen turnover in intrauterine growth restricted (IUGR) pregnancies, by determining circulating markers of type I collagen synthesis (carboxy-terminal propeptide of type I procollagen [PICP], representing bone formation) and degradation (cross-linked telopeptide of type I collagen [ICTP], representing bone resorption) as well as type III collagen synthesis (N-terminal propeptide of type-III procollagen [PIIINP], reflecting growth and tissue maturity). Plasma PICP, ICTP and PIIINP concentrations were measured in 40 mothers and their 20 asymmetric IUGR and 20 appropriate for gestational age (AGA) full-term fetuses and neonates on postnatal day 1-(N1) and 4-(N4). Fetal PICP, fetal and N4 ICTP, as well as fetal, N1 and N4 PIIINP concentrations were higher in the IUGR group (p ≤ 0.038, in all cases). In both groups, maternal PICP, ICTP and PIIINP concentrations were lower than fetal, N1 and N4 ones (p<0.001, in each case). Type I collagen turnover is enhanced in IUGR than AGA fetuses/neonates. Similarly, fetal/neonatal PIIINP concentrations are elevated in IUGR, probably due to stress, responsible for induction of tissue maturation, and/or to impaired excretory renal function, leading to reduced protein clearance. Fetal/neonatal PICP, ICTP and PIIINP concentrations are higher than maternal concentrations, possibly reflecting increased skeletal growth and collagen turnover in the former.

Self-Association of Lymphocytic Choriomeningitis Virus Nucleoprotein Is Mediated by Its N-Terminal Region and Is Not Required for Its Anti-Interferon Function

PubMed Central

Ortiz-Riaño, Emilio; Cheng, Benson Yee Hin

2012-01-01

Arenaviruses have a bisegmented, negative-strand RNA genome. Both the large (L) and small (S) genome segments use an ambisense coding strategy to direct the synthesis of two viral proteins. The L segment encodes the virus polymerase (L protein) and the matrix Z protein, whereas the S segment encodes the nucleoprotein (NP) and the glycoprotein precursor (GPC). NPs are the most abundant viral protein in infected cells and virions and encapsidate genomic RNA species to form an NP-RNA complex that, together with the virus L polymerase, forms the virus ribonucleoprotein (RNP) core capable of directing both replication and transcription of the viral genome. RNP formation predicts a self-association property of NPs. Here we document self-association (homotypic interaction) of the NP of the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV), as well as those of the hemorrhagic fever (HF) arenaviruses Lassa virus (LASV) and Machupo virus (MACV). We also show heterotypic interaction between NPs from both closely (LCMV and LASV) and distantly (LCMV and MACV) genetically related arenaviruses. LCMV NP self-association was dependent on the presence of single-stranded RNA and mediated by an N-terminal region of the NP that did not overlap with the previously described C-terminal NP domain involved in either counteracting the host type I interferon response or interacting with LCMV Z. PMID:22258244

Synthesis and Property of Ag(NP)/catechin/Gelatin Nanofiber

NASA Astrophysics Data System (ADS)

Nasir, Muhamad; Apriani, Dita

2017-12-01

Nanomaterial play important role future industry such as for the medical, food, pharmaceutical and cosmetic industry. Ag (NP) and catechin exhibit antibacterial property. Ag(NP) with diameter around 15 nm was synthesis by microwaved method. We have successfully produce Ag(NP)/catechin/gelatin nanofiber composite by electrospinning process. Ag(NP)/catechin/gelatin nanofiber was synthesized by using gelatin from tuna fish, polyethylene oxide (PEO), acetic acid as solvent and silver nanoparticle(NP)/catechin as bioactive component, respectively. Morphology and structure of bioactive catechin-gelatin nanofiber were characterized by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR), respectively. SEM analysis showed that morphology of nanofiber composite was smooth and had average diameter 398.97 nm. FTIR analysis results were used to confirm structure of catechin-gelatin nanofiber. It was confirmed by FTIR that specific vibration band peak amide A (N-H) at 3286,209 cm-1, amide B (N-H) 3069,396 cm-1, amide I (C=O) at 1643,813 cm-1, amide II (N-H and CN) at 1538,949 cm-1, amide III (C-N) at 1276,789 cm-1, C-O-C from polyethylene oxide at 1146,418 cm-1, respectively. When examined to S. Aureus bacteria, Ag/catechin/gelatin nanofiber show inhabitation performance around 40.44%. Ag(NP)/catechin/gelatin nanofiber has potential application antibacterial medical application.

AAV2 production with optimized N/P ratio and PEI-mediated transfection results in low toxicity and high titer for in vitro and in vivo applications.

PubMed

Huang, Xinping; Hartley, Antja-Voy; Yin, Yishi; Herskowitz, Jeremy H; Lah, James J; Ressler, Kerry J

2013-11-01

The adeno-associated virus (AAV) is one of the most useful viral vectors for gene delivery for both in vivo and in vitro applications. A variety of methods have been established to produce and characterize recombinant AAV (rAAV) vectors; however most methods are quite cumbersome and obtaining consistently high titer can be problematic. This protocol describes a triple-plasmid co-transfection approach with 25 kDa linear polyethylenimine (PEI) in 293 T cells for the production of AAV serotype 2. Seventy-two hours post-transfection, supernatant and cells were harvested and purified by a discontinuous iodixanol density gradient ultracentrifugation, then dialyzed and concentrated with an Amicon 15 100,000 MWCO concentration unit. To optimize the protocol for AAV2 production using PEI, various N/P ratios and DNA amounts were compared. We found that an N/P ratio of 40 coupled with 1.05 μg DNA per ml of media (21 μg DNA/15 cm dish) was found to produce the highest yields for viral replication and assembly measured multiple ways. The infectious units, as determined by serial dilution, were between 1×10(8) and 2×10(9) IU/ml. The genomic titer of the viral stock was determined by qPCR and ranged from 2×10(12) to 6×10(13) VG/ml. These viral vectors showed high expression both in vivo within the brain and in vitro in cell culture. The use of linear 25 kDa polyethylenamine PEI as a transfection reagent is a simple, more cost-effective, and stable means of high-throughput production of high-titer AAV serotype 2. The use of PEI also eliminates the need to change cell medium post-transfection, lowering cost and workload, while producing high-titer, efficacious AAV2 vectors for routine gene transfer. Copyright © 2013 Elsevier B.V. All rights reserved.

A Redundant Role of Human Thyroid Peroxidase Propeptide for Cellular, Enzymatic, and Immunological Activity

PubMed Central

Góra, Monika; Buckle, Ashley M.; Porebski, Benjamin T.; Kemp, E. Helen; Sutton, Brian J.; Czarnocka, Barbara; Banga, J. Paul

2014-01-01

Background: Thyroid peroxidase (TPO) is a dimeric membrane-bound enzyme of thyroid follicular cells, responsible for thyroid hormone biosynthesis. TPO is also a common target antigen in autoimmune thyroid disease (AITD). With two active sites, TPO is an unusual enzyme, and thus there is much interest in understanding its structure and role in AITD. Homology modeling has shown TPO to be composed of different structural modules, as well as a propeptide sequence. During the course of studies to obtain homogeneous preparations of recombinant TPO for structural studies, we investigated the role of the large propeptide sequence in TPO. Methods: An engineered recombinant human TPO preparation expressed in Chinese hamster ovary (CHO) cells lacking the propeptide (TPOΔpro; amino acid residues 21–108) was characterized and its properties compared to wild-type TPO. Plasma membrane localization was determined by cell surface protein biotinylation, and biochemical studies were performed to evaluate enzymatic activity and the effect of deglycosylation. Immunological investigations using autoantibodies from AITD patients and other epitope-specific antibodies that recognize conformational determinants on TPO were evaluated for binding to TPOΔpro by flow cytometry, immunocytochemistry, and capture enzyme-linked immunosorbent assay. Molecular modeling and dynamics simulation of TPOΔpro comprising a dimer of myeloperoxidase-like domains was performed in order to investigate the impact of propeptide removal and the role of glycosylation. Results: The TPOΔpro was expressed on the cell surface at comparable levels to wild-type TPO. The TPOΔpro was enzymatically active and recognized by patients' autoantibodies and a panel of epitope-specific antibodies, confirming structural integrity of the two major conformational determinants recognized by autoantibodies. Faithful intracellular trafficking and N-glycosylation of TPOΔpro was also maintained. Molecular modeling and dynamics

A redundant role of human thyroid peroxidase propeptide for cellular, enzymatic, and immunological activity.

PubMed

Godlewska, Marlena; Góra, Monika; Buckle, Ashley M; Porebski, Benjamin T; Kemp, E Helen; Sutton, Brian J; Czarnocka, Barbara; Banga, J Paul

2014-02-01

Thyroid peroxidase (TPO) is a dimeric membrane-bound enzyme of thyroid follicular cells, responsible for thyroid hormone biosynthesis. TPO is also a common target antigen in autoimmune thyroid disease (AITD). With two active sites, TPO is an unusual enzyme, and thus there is much interest in understanding its structure and role in AITD. Homology modeling has shown TPO to be composed of different structural modules, as well as a propeptide sequence. During the course of studies to obtain homogeneous preparations of recombinant TPO for structural studies, we investigated the role of the large propeptide sequence in TPO. An engineered recombinant human TPO preparation expressed in Chinese hamster ovary (CHO) cells lacking the propeptide (TPOΔpro; amino acid residues 21-108) was characterized and its properties compared to wild-type TPO. Plasma membrane localization was determined by cell surface protein biotinylation, and biochemical studies were performed to evaluate enzymatic activity and the effect of deglycosylation. Immunological investigations using autoantibodies from AITD patients and other epitope-specific antibodies that recognize conformational determinants on TPO were evaluated for binding to TPOΔpro by flow cytometry, immunocytochemistry, and capture enzyme-linked immunosorbent assay. Molecular modeling and dynamics simulation of TPOΔpro comprising a dimer of myeloperoxidase-like domains was performed in order to investigate the impact of propeptide removal and the role of glycosylation. The TPOΔpro was expressed on the cell surface at comparable levels to wild-type TPO. The TPOΔpro was enzymatically active and recognized by patients' autoantibodies and a panel of epitope-specific antibodies, confirming structural integrity of the two major conformational determinants recognized by autoantibodies. Faithful intracellular trafficking and N-glycosylation of TPOΔpro was also maintained. Molecular modeling and dynamics simulations were consistent with

Effects of the propeptide of group X secreted phospholipase A(2) on substrate specificity and interfacial activity on phospholipid monolayers.

PubMed

Point, Vanessa; Bénarouche, Anaïs; Jemel, Ikram; Parsiegla, Goetz; Lambeau, Gérard; Carrière, Frédéric; Cavalier, Jean-François

2013-01-01

Group X secreted phospholipase A(2) (GX sPLA(2)) plays important physiological roles in the gastrointestinal tract, in immune and sperm cells and is involved in several types of inflammatory diseases. It is secreted either as a mature enzyme or as a mixture of proenzyme (with a basic 11 amino acid propeptide) and mature enzyme. The role of the propeptide in the repression of sPLA(2) activity has been studied extensively using liposomes and micelles as model interfaces. These substrates are however not always suitable for detecting some fine tuning of lipolytic enzymes. In the present study, the monolayer technique is used to compare PLA(2) activity of recombinant mouse GX sPLA(2) (mGX) and its pro-form (PromGX) on monomolecular films of dilauroyl-phosphatidyl-ethanolamine (DLPE), -choline (DLPC) and -glycerol (DLPG). The PLA(2) activity and substrate specificity of mGX (PE ≈ PG > PC) were found to be surface pressure-dependent. mGX displayed a high activity on DLPE and DLPG but not on DLPC monolayers up to surface pressures corresponding to the lateral pressure of biological membranes (30-35 mN/m). Overall, the propeptide impaired the enzyme activity, particularly on DLPE whatever the surface pressure. However some conditions could be found where the propeptide had little effects on the repression of PLA(2) activity. In particular, both PromGX and mGX had similar activities on DLPG at a surface pressure of 30 mN/m. These findings show that PromGX can be potentially active depending on the presentation of the substrate (i.e., lipid packing) and one cannot exclude such an activity in a physiological context. A structural model of PromGX was built to investigate how the propeptide controls the activity of GX sPLA(2). This model shows that the propeptide is located within the interfacial binding site (i-face) and could disrupt both the interfacial binding of the enzyme and the access to the active site by steric hindrance. Copyright © 2012 Elsevier Masson SAS

Contributions of the N- and C-terminal helical segments to the lipid-free structure and lipid interaction of apolipoprotein A-I.

PubMed

Tanaka, Masafumi; Dhanasekaran, Padmaja; Nguyen, David; Ohta, Shinya; Lund-Katz, Sissel; Phillips, Michael C; Saito, Hiroyuki

2006-08-29

The tertiary structure of lipid-free apolipoprotein (apo) A-I in the monomeric state comprises two domains: a N-terminal alpha-helix bundle and a less organized C-terminal domain. This study examined how the N- and C-terminal segments of apoA-I (residues 1-43 and 223-243), which contain the most hydrophobic regions in the molecule and are located in opposite structural domains, contribute to the lipid-free conformation and lipid interaction. Measurements of circular dichroism in conjunction with tryptophan and 8-anilino-1-naphthalenesulfonic acid fluorescence data demonstrated that single (L230P) or triple (L230P/L233P/Y236P) proline insertions into the C-terminal alpha helix disrupted the organization of the C-terminal domain without affecting the stability of the N-terminal helix bundle. In contrast, proline insertion into the N terminus (Y18P) disrupted the bundle structure in the N-terminal domain, indicating that the alpha-helical segment in this region is part of the helix bundle. Calorimetric and gel-filtration measurements showed that disruption of the C-terminal alpha helix significantly reduced the enthalpy and free energy of binding of apoA-I to lipids, whereas disruption of the N-terminal alpha helix had only a small effect on lipid binding. Significantly, the presence of the Y18P mutation offset the negative effects of disruption/removal of the C-terminal helical domain on lipid binding, suggesting that the alpha helix around Y18 concealed a potential lipid-binding region in the N-terminal domain, which was exposed by the disruption of the helix-bundle structure. When these results are taken together, they indicate that the alpha-helical segment in the N terminus of apoA-I modulates the lipid-free structure and lipid interaction in concert with the C-terminal domain.

A novel calmodulin-regulated Ca2+-ATPase (ACA2) from Arabidopsis with an N-terminal autoinhibitory domain

NASA Technical Reports Server (NTRS)

Harper, J. F.; Hong, B.; Hwang, I.; Guo, H. Q.; Stoddard, R.; Huang, J. F.; Palmgren, M. G.; Sze, H.; Evans, M. L. (Principal Investigator)

1998-01-01

To study transporters involved in regulating intracellular Ca2+, we isolated a full-length cDNA encoding a Ca2+-ATPase from a model plant, Arabidopsis, and named it ACA2 (Arabidopsis Ca2+-ATPase, isoform 2). ACA2p is most similar to a "plasma membrane-type" Ca2+-ATPase, but is smaller (110 kDa), contains a unique N-terminal domain, and is missing a long C-terminal calmodulin-binding regulatory domain. In addition, ACA2p is localized to an endomembrane system and not the plasma membrane, as shown by aqueous-two phase fractionation of microsomal membranes. ACA2p was expressed in yeast as both a full-length protein (ACA2-1p) and an N-terminal truncation mutant (ACA2-2p; Delta residues 2-80). Only the truncation mutant restored the growth on Ca2+-depleted medium of a yeast mutant defective in both endogenous Ca2+ pumps, PMR1 and PMC1. Although basal Ca2+-ATPase activity of the full-length protein was low, it was stimulated 5-fold by calmodulin (50% activation around 30 nM). In contrast, the truncated pump was fully active and insensitive to calmodulin. A calmodulin-binding sequence was identified within the first 36 residues of the N-terminal domain, as shown by calmodulin gel overlays on fusion proteins. Thus, ACA2 encodes a novel calmodulin-regulated Ca2+-ATPase distinguished by a unique N-terminal regulatory domain and a non-plasma membrane localization.

The Ebola Virus VP30-NP Interaction Is a Regulator of Viral RNA Synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirchdoerfer, Robert N.; Moyer, Crystal L.; Abelson, Dafna M.

Filoviruses are capable of causing deadly hemorrhagic fevers. All nonsegmented negative-sense RNA-virus nucleocapsids are composed of a nucleoprotein (NP), a phosphoprotein (VP35) and a polymerase (L). However, the VP30 RNA-synthesis co-factor is unique to the filoviruses. The assembly, structure, and function of the filovirus RNA replication complex remain unclear. Here, we have characterized the interactions of Ebola, Sudan and Marburg virus VP30 with NP using in vitro biochemistry, structural biology and cell-based mini-replicon assays. We have found that the VP30 C-terminal domain interacts with a short peptide in the C-terminal region of NP. Further, we have solved crystal structures ofmore » the VP30-NP complex for both Ebola and Marburg viruses. These structures reveal that a conserved, proline-rich NP peptide binds a shallow hydrophobic cleft on the VP30 C-terminal domain. Structure-guided Ebola virus VP30 mutants have altered affinities for the NP peptide. Correlation of these VP30-NP affinities with the activity for each of these mutants in a cell-based mini-replicon assay suggests that the VP30-NP interaction plays both essential and inhibitory roles in Ebola virus RNA synthesis.« less

Short-term effects of teriparatide versus placebo on bone biomarkers, structure, and fracture healing in women with lower-extremity stress fractures: A pilot study.

PubMed

Almirol, Ellen A; Chi, Lisa Y; Khurana, Bharti; Hurwitz, Shelley; Bluman, Eric M; Chiodo, Christopher; Matzkin, Elizabeth; Baima, Jennifer; LeBoff, Meryl S

2016-09-01

In this pilot, placebo-controlled study, we evaluated whether brief administration of teriparatide (TPTD) in premenopausal women with lower-extremity stress fractures would increase markers of bone formation in advance of bone resorption, improve bone structure, and hasten fracture healing according to magnetic resonance imaging (MRI). Premenopausal women with acute lower-extremity stress fractures were randomized to injection of TPTD 20-µg subcutaneous (s.c.) (n = 6) or placebo s.c. (n = 7) for 8 weeks. Biomarkers for bone formation N-terminal propeptide of type I procollagen (P1NP) and osteocalcin (OC) and resorption collagen type-1 cross-linked C-telopeptide (CTX) and collagen type 1 cross-linked N-telopeptide (NTX) were measured at baseline, 4 and 8 weeks. The area between the percent change of P1NP and CTX over study duration is defined as the anabolic window. To assess structural changes, peripheral quantitative computed topography (pQCT) was measured at baseline, 8 and 12 weeks at the unaffected tibia and distal radius. The MRI of the affected bone assessed stress fracture healing at baseline and 8 weeks. After 8 weeks of treatment, bone biomarkers P1NP and OC increased more in the TPTD- versus placebo-treated group (both p ≤ 0.01), resulting in a marked anabolic window (p ≤ 0.05). Results from pQCT demonstrated that TPTD-treated women showed a larger cortical area and thickness compared to placebo at the weight bearing tibial site, while placebo-treated women had a greater total tibia and cortical density. No changes at the radial sites were observed between groups. According to MRI, 83.3% of the TPTD- and 57.1% of the placebo-treated group had improved or healed stress fractures (p = 0.18). In this randomized, pilot study, brief administration of TPTD showed anabolic effects that TPTD may help hasten fracture healing in premenopausal women with lower-extremity stress fractures. Larger prospective studies are warranted to determine

Calcium and Bone Turnover Markers in Acromegaly: A Prospective, Controlled Study.

PubMed

Constantin, Tina; Tangpricha, Vin; Shah, Reshma; Oyesiku, Nelson M; Ioachimescu, Octavian C; Ritchie, James; Ioachimescu, Adriana G

2017-07-01

Acromegaly has been associated with calcium-phosphate and bone turnover alterations. Controlled studies of these interactions are sparse. To evaluate calcium and bone metabolism in active and treated acromegaly. We conducted a controlled, prospective study at a tertiary referral center. We studied 22 patients with acromegaly referred for surgical or medical therapy (ACM) and 22 with nonfunctioning pituitary adenomas referred for surgery (control). Calcium (serum and urine), phosphorus, parathyroid hormone (PTH), 25-hydroxy- and 1,25-dihydroxy-vitamin D, bone turnover markers [serum C-terminal telopeptide of type 1 collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP)], and cytokines [receptor activator of nuclear factor κB ligand (RANK-L) and osteoprotegerin (OPG)] at baseline and 3 to 6 months after treatment. At baseline, the ACM group had lower PTH levels than controls (36.3 ± 13.9 pg/mL vs 56.0 ± 19.9 pg/mL) and higher phosphorus (4.34 ± 0.71 mg/dL vs 3.55 ± 0.50 mg/dL) (P < 0.01). Groups had similar levels of serum and urine calcium and 25-hydroxy- and 1,25-dihydroxy-vitamin D. The ACM group had higher bone turnover markers than control; P1NP and CTX were strongly correlated (r2 = 0.82, P < 0.05). CTX was dependent on age and disease group but not on sex or gonadal status. After treatment of acromegaly, serum calcium (9.52 ± 0.43 mg/dL to 9.26 ± 0.28 mg/dL), phosphorus (4.34 ± 0.71 mg/dL to 3.90 ± 0.80 mg/dL), and CTX (0.91 ± 0.75 ng/mL to 0.63 ± 0.68 ng/mL) decreased, while PTH increased (36.3 ± 13.9 pg/mL to 48.9 ± 16.7 pg/mL) (P < 0.01). 25-hydroxy-vitamin D, P1NP, and RANK-L/OPG ratio did not change significantly. Acromegaly patients exhibited PTH-independent calcium-phosphate alterations and enhanced coupled bone formation and resorption. Within 6 months of treatment, bone resorption decreased, whereas RANK-L/OPG changes were inconsistent. Copyright © 2017 Endocrine Society

Using p-type PbS Quantum Dots to Quench Photocurrent of Fullerene-Au NP@MoS2 Composite Structure for Ultrasensitive Photoelectrochemical Detection of ATP.

PubMed

Li, Meng-Jie; Zheng, Ying-Ning; Liang, Wen-Bin; Yuan, Ruo; Chai, Ya-Qin

2017-12-06

Ultrasensitive and rapid quantification of the universal energy currency adenosine triphosphate (ATP) is an extremely critical mission in clinical applications. In this work, a "signal-off" photoelectrochemical (PEC) biosensor was designed for ultrasensitive ATP detection based on a fullerene (C 60 )-decorated Au nanoparticle@MoS 2 (C 60 -Au NP@MoS 2 ) composite material as a signal indicator and a p-type PbS quantum dot (QD) as an efficient signal quencher. Modification of wide band gap C 60 with narrow band gap MoS 2 to form an ideal PEC signal indicator was proposed, which could significantly improve photocurrent conversion efficiency, leading to a desirable PEC signal. In the presence of p-type PbS QDs, the PEC signal of n-type C 60 -Au NP@MoS 2 was effectively quenched because p-type PbS QDs could compete with C 60 -Au NP@MoS 2 to consume light energy and electron donor. Besides, the conversion of a limited amount of target ATP into an amplified output PbS QD-labeled short DNA sequence (output S 1 ) was achieved via target-mediated aptazyme cycling amplification strategy, facilitating ultrasensitive ATP detection. The proposed signal-off PEC strategy exhibited a wide linear range from 1.00 × 10 -2 pM to 100 nM with a low detection limit of 3.30 fM. Importantly, this proposed strategy provides a promising platform to detect ATP at ultralow levels and has potential applications, including diagnosis of ATP-related diseases, monitoring of diseases progression and evaluation of prognosis.

N-terminal RASSF family

PubMed Central

Underhill-Day, Nicholas; Hill, Victoria

2011-01-01

Epigenetic inactivation of tumor suppressor genes is a hallmark of cancer development. RASSF1A (Ras Association Domain Family 1 isoform A) tumor suppressor gene is one of the most frequently epigenetically inactivated genes in a wide range of adult and children's cancers and could be a useful molecular marker for cancer diagnosis and prognosis. RASSF1A has been shown to play a role in several biological pathways, including cell cycle control, apoptosis and microtubule dynamics. RASSF2, RASSF4, RASSF5 and RASSF6 are also epigenetically inactivated in cancer but have not been analyzed in as wide a range of malignancies as RASSF1A. Recently four new members of the RASSF family were identified these are termed N-Terminal RASSF genes (RASSF7–RASSF10). Molecular and biological analysis of these newer members has just begun. This review highlights what we currently know in respects to structural, functional and molecular properties of the N-Terminal RASSFs. PMID:21116130

Differential effects of C- and N-terminal substance P metabolites on the release of amino acid neurotransmitters from the spinal cord: potential role in nociception.

PubMed

Skilling, S R; Smullin, D H; Larson, A A

1990-04-01

Extensive evidence implicates Substance P [SP(1-11)] as a primary afferent neurotransmitter or modulator of nociceptive information, and there is increasing evidence that the excitatory amino acids aspartate (Asp) and glutamate (Glu) may also act as nociceptive neurotransmitters. We have previously demonstrated that nociceptive stimulation (metatarsal injection of formalin) caused a tetrodotoxin (TTX)-sensitive release of Asp and a TTX-insensitive release of Glu from the dorsal spinal cord. We have also shown release of Asp and Glu following the direct infusion of SP(1-11), suggesting that formalin-induced Asp or Glu changes could be secondary to an initial release of SP(1-11). In contrast to nociception, pretreatment with TTX, reported here, had no effect on the SP(1-11)-induced release of Asp, suggesting a presynaptic mechanism. Behavioral experiments, in both our laboratory, and others, now suggest that the N-terminal products of SP metabolism play a distinct role in the modulation of SP(1-11) nociception, possibly through an interaction with an opiate receptor. To test the hypothesis that N- and C-terminal fragments of SP produce opposite effects on biochemical events potentially involved in nociception, we compared the effects of infusion of the N-terminal metabolite SP(1-7) and the C-terminal metabolite SP(5-11) on changes in the ECF concentration of amino acids in the spinal cord as a measure of their apparent release, using microdialysis. Intradiaylsate infusion of SP(5-11) increased the release of Asp, Glu, asparagine (Asn), glycine (Gly), and taurine (Tau). The changes in Asp, Glu, and Tau were similar in direction and magnitude to changes produced by SP(1-11) or formalin injection, further supporting the hypothesis that the C-terminal is responsible for the nociceptive effects of SP(1-11). In contrast, infusion of SP(1-7) significantly decreased the release of Asn, Tau, Glu, and Gly. This inhibition of amino acid release is consistent with the hypothesis

Photonuclear reactions in astrophysical p-process: Theoretical calculations and experiment simulation based on ELI-NP

NASA Astrophysics Data System (ADS)

Xu, Yi; Luo, Wen; Balabanski, Dimiter; Goriely, Stephane; Matei, Catalin; Tesileanu, Ovidiu

2017-09-01

The astrophysical p-process is an important way of nucleosynthesis to produce the stable and proton-rich nuclei beyond Fe which can not be reached by the s- and r-processes. In the present study, the astrophysical reaction rates of (γ,n), (γ,p), and (γ,α) reactions are computed within the modern reaction code TALYS for about 3000 stable and proton-rich nuclei with 12 < Z < 110. The nuclear structure ingredients involved in the calculation are determined from experimental data whenever available and, if not, from global microscopic nuclear models. In particular, both of the Wood-Saxon potential and the double folding potential with density dependent M3Y (DDM3Y) effective interaction are used for the calculations. It is found that the photonuclear reaction rates are very sensitive to the nuclear potential, and the better determination of nuclear potential would be important to reduce the uncertainties of reaction rates. Meanwhile, the Extreme Light Infrastructure-Nuclear Physics (ELI-NP) facility is being developed, which will provide the great opportunity to experimentally study the photonuclear reactions in p-process. Simulations of the experimental setup for the measurements of the photonuclear reactions 96Ru(γ,p) and 96Ru(γ,α) are performed. It is shown that the experiments of photonuclear reactions in p-process based on ELI-NP are quite promising.

Saccharomyces cerevisiae RNA Polymerase I Terminates Transcription at the Reb1 Terminator In Vivo

PubMed Central

Reeder, Ronald H.; Guevara, Palmira; Roan, Judith G.

1999-01-01

We have mapped transcription termination sites for RNA polymerase I in the yeast Saccharomyces cerevisiae. S1 nuclease mapping shows that the primary terminator is the Reb1p terminator located at +93 downstream of the 3′ end of 25S rRNA. Reverse transcription coupled with quantitative PCR shows that approximately 90% of all transcripts terminate at this site. Transcripts which read through the +93 site quantitatively terminate at a fail-safe terminator located further downstream at +250. Inactivation of Rnt1p (an RNase III involved in processing the 3′ end of 25S rRNA) greatly stabilizes transcripts extending to both sites and increases readthrough at the +93 site. In vivo assay of mutants of the Reb1p terminator shows that this site operates in vivo by the same mechanism as has previously been delineated through in vitro studies. PMID:10523625

In vitro characterization of the RS motif in N-terminal head domain of goldfish germinal vesicle lamin B3 necessary for phosphorylation of the p34cdc2 target serine by SRPK1☆

PubMed Central

Yamaguchi, Akihiko; Iwatani, Miho; Ogawa, Mariko; Kitano, Hajime; Matsuyama, Michiya

2013-01-01

The nuclear envelopes surrounding the oocyte germinal vesicles of lower vertebrates (fish and frog) are supported by the lamina, which consists of the protein lamin B3 encoded by a gene found also in birds but lost in the lineage leading to mammals. Like other members of the lamin family, goldfish lamin B3 (gfLB3) contains two putative consensus phosphoacceptor p34cdc2 sites (Ser-28 and Ser-398) for the M-phase kinase to regulate lamin polymerization on the N- and C-terminal regions flanking a central rod domain. Partial phosphorylation of gfLB3 occurs on Ser-28 in the N-terminal head domain in immature oocytes prior to germinal vesicle breakdown, which suggests continual rearrangement of lamins by a novel lamin kinase in fish oocytes. We applied the expression-screening method to isolate lamin kinases by using phosphorylation site Ser-28-specific monoclonal antibody and a vector encoding substrate peptides from a goldfish ovarian cDNA library. As a result, SRPK1 was screened as a prominent lamin kinase candidate. The gfLB3 has a short stretch of the RS repeats (9-SRASTVRSSRRS-20) upstream of the Ser-28, within the N-terminal head. This stretch of repeats is conserved among fish lamin B3 but is not found in other lamins. In vitro phosphorylation studies and GST-pull down assay revealed that SRPK1 bound to the region of sequential RS repeats (9–20) with affinity and recruited serine into the active site by a grab-and-pull manner. These results indicate SRPK1 may phosphorylate the p34cdc2 site in the N-terminal head of GV-lamin B3 at the RS motifs, which have the general property of aggregation. PMID:23772390

Accumulation of N and P in the Legume Lespedeza davurica in Controlled Mixtures with the Grass Bothriochloa ischaemum under Varying Water and Fertilization Conditions.

PubMed

Xu, Bingcheng; Xu, Weizhou; Wang, Zhi; Chen, Zhifei; Palta, Jairo A; Chen, Yinglong

2018-01-01

Water and fertilizers affect the nitrogen (N) and phosphorus (P) acquisition and allocation among organs in dominant species in natural vegetation on the semiarid Loess Plateau. This study aimed to clarify the N and P accumulation and N:P ratio at organ and plant level of a local legume species mixed with a grass species under varying water and fertilizer supplies, and thus to fully understand the requirements and balance of nutrient elements in response to growth conditions change of native species. The N and P concentration in the organ (leaf, stem, and root) and plant level of Lespedeza davurica (C 3 legume), were examined when intercropped with Bothriochloa ischaemum (C 4 grass). The two species were grown outdoors in pots under 80, 60, and 40% of soil water field capacity (FC), -NP, +N, +P, and +NP supply and the grass:legume mixture ratios of 2:10, 4:8, 6:6, 8:4, 10:2, and 12:0. The three set of treatments were under a randomized complete block design. Intercropping with B. ischaemum did not affect N concentrations in leaf, stem and root of L. davurica , but reduced P concentration in each organ under P fertilization. Only leaf N concentration in L. davurica showed decreasing trend as soil water content decreased under all fertilization and mixture proportion treatments. Stems had the lowest, while roots had the highest N and P concentration. As the mixture proportion of L. davurica decreased under P fertilization, P concentration in leaf and root also decreased. The N concentration in L. davurica at the whole plant level was 11.1-17.2%. P fertilization improved P concentration, while decreased N:P ratio in L. davurica . The N:P ratios were less than 14.0 under +P and +NP treatments. Our results implied that exogenous N and P fertilizer application may change the N:P stoichiometry and influence the balance between nutrients and organs of native dominant species in natural grassland, and P element should be paid more attention when considering rehabilitating

Land use change influences soil C, N, and P stoichiometry under ‘Grain-to-Green Program’ in China

PubMed Central

Fazhu, Zhao; Jiao, Sun; Chengjie, Ren; Di, Kang; Jian, Deng; Xinhui, Han; Gaihe, Yang; Yongzhong, Feng; Guangxin, Ren

2015-01-01

Changes in land use might affect the combined C, N and P stoichiometry in soil. The Grain-to-Green Program (GTGP), which converts low-yield croplands or abandoned lands into forest, shrub, and/or grassland, was the largest land reforestation project in China. This study collected the reported C, N and P contents of soil in GTGP zones to achieve the factors driving the changes in the C:N, C:P, and N:P values. The results showed that the annual average precipitation exerted significant effects on the C:P value, and on the N:P value became significant 20 years after the change in land use. The annual average temperature was the main factor affecting the C:N value during the first 10 years, while the annual average precipitation strongly affected this value afterwards. In addition, “Redfield-like” interactions between C, N, and P in the soil may exist. A linear regression revealed significant positive correlations between the C:N, C:P, and N:P values and the restoration age, temperature, and precipitation after a change in land use. Therefore large-scale changes in land use under the ‘GTGP’ program might significantly affect the C:N, C:P and N:P ratios in soil. PMID:25988714

Association between basal metabolic function and bone metabolism in postmenopausal women with type 2 diabetes.

PubMed

Ogata, Makiko; Ide, Risa; Takizawa, Miho; Tanaka, Mizuho; Tetsuo, Tamaki; Sato, Asako; Iwasaki, Naoko; Uchigata, Yasuko

2015-01-01

Diabetes is a risk factor for osteoporosis, and glycemic control is critical during osteoporosis treatment in patients with type 2 diabetes (T2D). However, diabetic therapies have potentially adverse effects on bone metabolism. Additionally, biomarkers for bone metabolism are directly affected by drug therapies for osteoporosis. This study examined resting energy expenditure (REE) and respiratory quotient (RQ) as indices of bone metabolism in postmenopausal Japanese women with T2D. Forty-six postmenopausal Japanese women with T2D were examined. Procollagen type 1 N-terminal propeptide (P1NP, a fasting serum bone formation marker) and carboxy-terminal collagen cross-links-1 (CTX-1, a resorption marker) were evaluated, along with intact parathyroid hormone, 25-hydroxyvitamin D (25[OH]D), urine microalbumin, motor nerve conduction velocity, sensory nerve conduction velocity, R-R interval, body composition, REE, RQ, and bone mineral density at the nondominant distal radius. The mean T-score was low with high variance (-1.7 ± 1.6), and 18 patients (39%) met the criteria for osteoporosis. REE was positively correlated with body mass index (β = 0.517; r(2) = 0.250), serum calcium (β = 0.624; r(2) = 0.200), glycated hemoglobin A1C for the previous 6 mo (β = 0.395; r(2) = 0.137), and the serum P1NP/CTX-1 ratio (β = 0.380; r(2) = 0.144). RQ was positively correlated with serum 25(OH)D (β = 0.387; r(2) = 0.131). The basal metabolic rate and diabetic pathophysiology are interrelated with bone turnover. Copyright © 2015 Elsevier Inc. All rights reserved.

N-terminal acetylation modulates Bax targeting to mitochondria.

PubMed

Alves, Sara; Neiri, Leire; Chaves, Susana Rodrigues; Vieira, Selma; Trindade, Dário; Manon, Stephen; Dominguez, Veronica; Pintado, Belen; Jonckheere, Veronique; Van Damme, Petra; Silva, Rui Duarte; Aldabe, Rafael; Côrte-Real, Manuela

2018-02-01

The pro-apoptotic Bax protein is the main effector of mitochondrial permeabilization during apoptosis. Bax is controlled at several levels, including post-translational modifications such as phosphorylation and S-palmitoylation. However, little is known about the contribution of other protein modifications to Bax activity. Here, we used heterologous expression of human Bax in yeast to study the involvement of N-terminal acetylation by yNaa20p (yNatB) on Bax function. We found that human Bax is N-terminal (Nt-)acetylated by yNaa20p and that Nt-acetylation of Bax is essential to maintain Bax in an inactive conformation in the cytosol of yeast and Mouse Embryonic Fibroblast (MEF) cells. Bax accumulates in the mitochondria of yeast naa20Δ and Naa25 -/- MEF cells, but does not promote cytochrome c release, suggesting that an additional step is required for full activation of Bax. Altogether, our results show that Bax N-terminal acetylation by NatB is involved in its mitochondrial targeting. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of the 6 p 2(3 P 0) n p Rydberg series of bismuth by multiphoton excitation

NASA Astrophysics Data System (ADS)

Bühler, B.; Cremer, C.; Gerber, G.

1985-03-01

Rydberg states of the odd-parity series 6 p 2(3 p 0) n p of BiI are excited by a three-photon process. A two-photon dissociation of Bi2 into excited atomic states followed by a one-photon absorption leads to highly excited atomic Rydberg states up to n = 32. States of the even-parity Rydberg series 6 p 2(3 p 0) nsJ=1/2, ndJ=3/2 and ndJ=5/2 are also observed. In order to avoid the background caused by ionization of the bismuth molecules we performed a two-color excitation with pulsed dye lasers. With this experiment the 6 p 2(3 p 0) npJ=3/2 Rydberg series could be resolved up to n=75. The increasing quantum defect of this series is due to a perturbing state close to the first ionization limit. By a MQDT analysis we obtain the energy of the perturbing state and a value of 58,761.68±0.1 cm-1 for the first ionization limit of atomic bismuth.

Comparative modeling of InP solar cell structures

NASA Technical Reports Server (NTRS)

Jain, R. K.; Weinberg, I.; Flood, D. J.

1991-01-01

The comparative modeling of p(+)n and n(+)p indium phosphide solar cell structures is studied using a numerical program PC-1D. The optimal design study has predicted that the p(+)n structure offers improved cell efficiencies as compared to n(+)p structure, due to higher open-circuit voltage. The various cell material and process parameters to achieve the maximum cell efficiencies are reported. The effect of some of the cell parameters on InP cell I-V characteristics was studied. The available radiation resistance data on n(+)p and p(+)p InP solar cells are also critically discussed.

Muscle-specific transgenic expression of porcine myostatin propeptide enhances muscle growth in mice.

PubMed

Wang, Kaiyun; Li, Zicong; Li, Yang; Zeng, Jinyong; He, Chang; Yang, Jinzeng; Liu, Dewu; Wu, Zhenfang

2013-10-01

Myostatin is a well-known negative regulator of skeletal muscle growth. Inhibition of myostatin activity results in increased muscle mass. Myostatin propeptide, as a myostatin antagonist, could be applied to promote meat production in livestock such as pigs. In this study, we generated a transgenic mouse model expressing porcine myostatin propeptide under the control of muscle-specific regulatory elements. The mean body weight of transgenic mice from a line expressing the highest level of porcine myostatin propeptide was increased by 5.4 % (P = 0.023) and 3.2 % (P = 0.031) in males and females, respectively, at 8 weeks of age. Weight of carcass, fore limb and hind limb was respectively increased by 6.0 % (P = 0.038), 9.0 % (P = 0.014), 8.7 % (P = 0.036) in transgenic male mice, compared to wild-type male controls at the age of 9 weeks. Similarly, carcass, fore limb and hind limb of transgenic female mice was 11.4 % (P = 0.002), 14.5 % (P = 0.006) and 14.5 % (P = 0.03) respectively heavier than that of wild-type female mice. The mean cross-section area of muscle fiber was increased by 17 % (P = 0.002) in transgenic mice, in comparison with wild-type controls. These results demonstrated that porcine myostatin propeptide is effective in enhancement of muscle growth. The present study provided useful information for future study on generation of transgenic pigs overexpressing porcine myostatin propeptide for improvement of muscle mass.

Preparation of p-type GaN-doped SnO2 thin films by e-beam evaporation and their applications in p-n junction

NASA Astrophysics Data System (ADS)

Lv, Shuliang; Zhou, Yawei; Xu, Wenwu; Mao, Wenfeng; Wang, Lingtao; Liu, Yong; He, Chunqing

2018-01-01

Various transparent GaN-doped SnO2 thin films were deposited on glass substrates by e-beam evaporation using GaN:SnO2 targets of different GaN weight ratios. It is interesting to find that carrier polarity of the thin films was converted from n-type to p-type with increasing GaN ratio higher than 15 wt.%. The n-p transition in GaN-doped SnO2 thin films was explained for the formation of GaSn and NO with increasing GaN doping level in the films, which was identified by Hall measurement and XPS analysis. A transparent thin film p-n junction was successfully fabricated by depositing p-type GaN:SnO2 thin film on SnO2 thin film, and a low leakage current (6.2 × 10-5 A at -4 V) and a low turn-on voltage of 1.69 V were obtained for the p-n junction.

Multiple-interactions among EMILIN1 and EMILIN2 N- and C-terminal domains.

PubMed

Bot, Simonetta; Andreuzzi, Eva; Capuano, Alessandra; Schiavinato, Alvise; Colombatti, Alfonso; Doliana, Roberto

2015-01-01

EMILIN1 and EMILIN2 belong to a family of extracellular matrix glycoproteins characterized by the N-terminal cysteine-rich EMI domain, a long segment with high probabilty for coiled-coil structure formation and a C-terminal gC1q domain. To study EMILIN1 and EMILIN2 interaction and assembly we have applied qualitative and quantitative two hybrid systems using constructs corresponding to the gC1q and EMI domains. The identified interactions were further confirmed in yeast extracts of co-transfected cells followed by co-immunoprecipitation. The data indicated that gC1q domains are able to self-interact as well as to interact one each other and with the EMI domains, but no self interactions were detected between the EMI domains. Furthermore EMILINs interactions were studied in 293-EBNA cells co-transfected with full lenght EMILIN1 and EMILIN2 constructs. Specific antibodies were able to co-immunoprecipitate EMILINs, indicating that also full-lenght proteins can give rise to non-covalent homo- and hetero-multimers even if reduced and alkylated before mixing. Immunofluorescence analysis on mouse cell cultures and tissues sections with specific antibodies showed co-distribution of EMILIN1 and EMILIN2. Thus, we can hypothesize that EMILINs multimers are formed by head-to-tail interaction between C-terminal and N-terminal domains of EMILIN1 and/or EMILIN2 but also by tail-to-tail interaction between gC1q domains. These multiple interactions may regulate homo-typic and/or hetero-typic linear and eventually lateral branching assemblies of EMILIN1 and EMILIN2 in tissues. Copyright © 2014. Published by Elsevier B.V.

C-terminal substance P fragments elicit histamine release from a murine mast cell line.

PubMed

Krumins, S A; Broomfield, C A

1993-01-01

Incubation of mouse mast cells with C-terminal substance P fragments in the micromolar range caused a release of histamine. Maximum release was observed with the tetrapeptide SP(8-11), followed by the tripeptide SP(9-11). SP(6-11) and SP(5-11) were nearly equipotent, while SP(4-11) caused only a slight histamine release. The substance P parent molecule and the N-terminal substance P fragments SP(1-4), SP(1-6) and SP(1-7) evoked no release of histamine. In confirmation of our previous findings, incubation with neurokinin A caused a release comparable to that of SP(8-11). Whereas neurokinin A-induced release was partially preventable by pretreating the cells with the NK2 receptor-selective antagonist cyclo(Gln-Trp-Phe-(R)Gly[ANC-2]Leu-Met), SP(8-11)-induced release was completely abolished by such treatment. The results provide the first evidence for the involvement of NK2 tachykinin receptors in the release of histamine by C-terminal substance P fragments.

Anti-senescence and Anti-inflammatory Effects of the C-terminal Moiety of PTHrP Peptides in OA Osteoblasts.

PubMed

Platas, Julia; Guillén, Maria Isabel; Gomar, Francisco; Castejón, Miguel Angel; Esbrit, Pedro; Alcaraz, Maria José

2017-05-01

Osteoarthritis (OA) is characterized by degenerative changes in the whole joint leading to physical disability in the elderly population. This condition is associated with altered bone metabolism in subchondral areas suggesting that therapeutic strategies aimed at modifying bone cell metabolism may be of interest. We have investigated the effects of several parathyroid hormone-related protein (PTHrP)-derived peptides (1-37): (N-terminal), (107-111) and (107-139) (C-terminal) on senescence features induced by inflammatory stress in human OA osteoblasts. Incubation of these primary cells with interleukin(IL)-1β led to an increased expression of senescence markers senescence-associated-β-galactosidase activity, γH2AX foci, p16, p21, p53, and caveolin-1. PTHrP (107-111) and PTHrP (107-139) significantly reduced all these parameters. Both peptides decreased the production of IL-6 and prostaglandin E2 which was the consequence of cyclo-oxygenase-2 downregulation. PTHrP (107-139) also reduced tumor necrosis factor-α release. These anti-inflammatory effects would be related to the reduction of nuclear factor-κB activation by both peptides and activator protein-1 by PTHrP (107-139). The three PTHrP peptides favored osteoblastic function although the C-terminal domain of PTHrP was more efficient than its N-terminal domain. Our data support an anti-senescence and anti-inflammatory role for the C-terminal moiety of PTHrP with potential applications in chronic inflammatory conditions such as OA. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Rice No Pollen 1 (NP1) is required for anther cuticle formation and pollen exine patterning.

PubMed

Liu, Ze; Lin, Sen; Shi, Jianxin; Yu, Jing; Zhu, Lu; Yang, Xiujuan; Zhang, Dabing; Liang, Wanqi

2017-07-01

Angiosperm male reproductive organs (anthers and pollen grains) have complex and interesting morphological features, but mechanisms that underlie their patterning are poorly understood. Here we report the isolation and characterization of a male sterile mutant of No Pollen 1 (NP1) in rice (Oryza sativa). The np1-4 mutant exhibited smaller anthers with a smooth cuticle surface, abnormal Ubisch bodies, and aborted pollen grains covered with irregular exine. Wild-type exine has two continuous layers; but np1-4 exine showed a discontinuous structure with large granules of varying size. Chemical analysis revealed reduction in most of the cutin monomers in np1-4 anthers, and less cuticular wax. Map-based cloning suggested that NP1 encodes a putative glucose-methanol-choline oxidoreductase; and expression analyses found NP1 preferentially expressed in the tapetal layer from stage 8 to stage 10 of anther development. Additionally, the expression of several genes involved in biosynthesis and in the transport of lipid monomers of sporopollenin and cutin was decreased in np1-4 mutant anthers. Taken together, these observations suggest that NP1 is required for anther cuticle formation, and for patterning of Ubisch bodies and the exine. We propose that products of NP1 are likely important metabolites in the development of Ubisch bodies and pollen exine, necessary for polymerization, assembly, or both. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

[Differences in oligomerization of nucleocapsid protein of epidemic human influenza A(H1N1), A(H1N2) and B viruses].

PubMed

Prokudina, E N; Semenova, N P; Chumakov, V M; Burtseva, E I; Slepushkin, A N

2003-01-01

A comparative analysis of involving the nucleocapsid protein (NP) into shaping-up of SDS-resistant oligomers was carried out presently in circulating epidemic strains of human influenza, viruses A and B. The study results of viral isolates obtained from clinical samples and recent standard strains revealed that the involvement of NP in the SDS-resistant oligomers, which are different in various subtypes of influenza A viruses. According to this sign, the human viruses A(9H3N2) are close to the avian ones, in which, as proved by us previously, virtually the entire NP transforms itself into the oligomers resistant to SDS. About 10-20% of NP are involved in shaping-up the virus influenza A(H1N1) of SDS-resistant oligomers. No SDS-resistant NP-oligomers were detected in influenza of type B. It is suggested that the prevalence of human viruses A(H3N2) in NP-oligomers are the peculiarities of NP structure and of the presence of the PB1 protein from avian influenza virus.

Osteoporosis and osteopenia are not associated with T-cell activation in older cART-treated HIV-infected patients.

PubMed

Krikke, M; Klomberg, R C W; van der Veer, E; Tesselaar, K; Verhaar, H J J; Hoepelman, A I M; Arends, J E

2017-05-01

A higher risk of developing osteopenia/ osteoporosis has been seen in HIV-infected patients. We compared HIV-infected patients, all treated with combination antiretroviral therapy (cART), with a low bone mineral density (BMD) (T-score < -1) to those with a normal BMD (T-score > -1), examining the relation with T-cell activation and bone turnover markers (c-terminal telopeptide (CTX) and procollagen type 1 amino-terminal propeptide (P1NP)). In this single visit pilot study, bone turnover markers, T-cell activation (CD38 + HLA - DR +) and senescence (CD57+) of T cells were measured in patients who had previously undergone dual energy X-ray absorptiometry scanning. All study participants (n = 16) were male, on cART, with a median age of 61 years (IQR 56-66). Nine patients had osteopenia/osteoporosis. When comparing the patients with osteopenia/osteoporosis with those with a normal BMD, no differences in activation and senescence were found. A relation was seen between higher bone formation (P1NP) and patients who were on cART for longer. The median length of cART use was 5.5 years (IQR 4.5-7.8), with all patients on nucleoside reverse transcriptase inhibitors, 88% on tenofovir, 63% on non-nucleoside reverse transcriptase inhibitors (NNRTIs) and 38% on protease inhibitors. Osteopenia/osteoporosis was seen in 100% of the patients on protease inhibitors versus 30% of those on NNRTIs. This study did not find an association between activated T cells and BMD, thus did not explain the higher prevalence of osteopenia/osteoporosis in HIV-infected patients. Interestingly, this small pilot showed that cART might influence BMD, with a possible negative effect for protease inhibitors and a possible protective effect for NNRTIs. These results warrant further investigation.

Beyond good and evil: A putative continuum-sorting hypothesis for the functional role of proBDNF/BDNF-propeptide/mBDNF in antidepressant treatment.

PubMed

Diniz, Cassiano R A F; Casarotto, Plinio C; Resstel, Leonardo; Joca, Sâmia R L

2018-04-04

Depression and posttraumatic stress disorder are assumed to be maladaptive responses to stress and antidepressants are thought to counteract such responses by increasing BDNF (brain-derived neurotrophic factor) levels. BDNF acts through TrkB (tropomyosin-related receptor kinase B) and plays a central role in neuroplasticity. In contrast, both precursor proBDNF and BDNF propeptide (another metabolic product from proBDNF cleavage) have a high affinity to p75 receptor (p75R) and usually convey apoptosis and neuronal shrinkage. Although BDNF and proBDNF/propeptide apparently act in opposite ways, neuronal turnover and remodeling might be a final common way that both act to promote more effective neuronal networking, avoiding neuronal redundancy and the misleading effects of environmental contingencies. This review aims to provide a brief overview about the BDNF functional role in antidepressant action and about p75R and TrkB signaling to introduce the "continuum-sorting hypothesis." The resulting hypothesis suggests that both BDNF/proBDNF and BDNF/propeptide act as protagonists to fine-tune antidepressant-dependent neuroplasticity in crucial brain structures to modulate behavioral responses to stress. Copyright © 2018 Elsevier Ltd. All rights reserved.

Noncanonical Photodynamics of the Orange/Green Cyanobacteriochrome Power Sensor NpF2164g7 from the PtxD Phototaxis Regulator of Nostoc punctiforme.

PubMed

Kirpich, Julia S; Chang, Che-Wei; Madsen, Dorte; Gottlieb, Sean M; Martin, Shelley S; Rockwell, Nathan C; Lagarias, J Clark; Larsen, Delmar S

2018-05-08

Forward and reverse primary (<10 ns) and secondary (>10 ns) photodynamics of cyanobacteriochrome (CBCR) NpF2164g7 were characterized by global analysis of ultrafast broadband transient absorption measurements. NpF2164g7 is the most C-terminal bilin-binding GAF domain in the Nostoc punctiforme phototaxis sensor PtxD (locus Npun_F2164). Although a member of the canonical red/green CBCR subfamily phylogenetically, NpF2164g7 exhibits an orange-absorbing 15Z P o dark-adapted state instead of the typical red-absorbing 15Z P r dark-adapted state characteristic of this subfamily. The green-absorbing 15E P g photoproduct of NpF2164g7 is unstable, allowing this CBCR domain to function as a power sensor. Photoexcitation of the 15Z P o state triggers inhomogeneous excited-state dynamics with three spectrally and temporally distinguishable pathways to generate the light-adapted 15E P g state in high yield (estimated at 25-30%). Although observed in other CBCR domains, the inhomogeneity in NpF2164g7 extends far into secondary relaxation dynamics (10 ns -1 ms) through to formation of 15E P g . In the reverse direction, the primary dynamics after photoexcitation of 15E P g are qualitatively similar to those of other red/green CBCRs, but secondary dynamics involve a "pre-equilibrium" step before regenerating 15Z P o . The anomalous photodynamics of NpF2164g7 may reflect an evolutionary adaptation of CBCR sensors that function as broadband light intensity sensors.

Solution structure of the His12 --> Cys mutant of the N-terminal zinc binding domain of HIV-1 integrase complexed to cadmium.

PubMed Central

Cai, M.; Huang, Y.; Caffrey, M.; Zheng, R.; Craigie, R.; Clore, G. M.; Gronenborn, A. M.

1998-01-01

The solution structure of His12 --> Cys mutant of the N-terminal zinc binding domain (residues 1-55; IN(1-55)) of HIV-1 integrase complexed to cadmium has been solved by multidimensional heteronuclear NMR spectroscopy. The overall structure is very similar to that of the wild-type N-terminal domain complexed to zinc. In contrast to the wild-type domain, however, which exists in two interconverting conformational states arising from different modes of coordination of the two histidine side chains to the metal, the cadmium complex of the His12 --> Cys mutant exists in only a single form at low pH. The conformation of the polypeptide chain encompassing residues 10-18 is intermediate between the two forms of the wild-type complex. PMID:9865962

Sequence analysis of the lactococcal plasmid pNP40: a mobile replicon for coping with environmental hazards.

PubMed

O'Driscoll, Jonathan; Glynn, Frances; Fitzgerald, Gerald F; van Sinderen, Douwe

2006-09-01

The conjugative lactococcal plasmid pNP40, identified in Lactococcus lactis subsp. diacetylactis DRC3, possesses a potent complement of bacteriophage resistance systems, which has stimulated its application as a fitness-improving, food-grade genetic element for industrial starter cultures. The complete sequence of this plasmid allowed the mapping of previously known functions including replication, conjugation, bacteriocin resistance, heavy metal tolerance, and bacteriophage resistance. In addition, functions for cold shock adaptation and DNA damage repair were identified, further confirming pNP40's contribution to environmental stress protection. A plasmid cointegration event appears to have been part of the evolution of pNP40, resulting in a "stockpiling" of bacteriophage resistance systems.

Serum sclerostin levels associated with lumbar spine bone mineral density and bone turnover markers in patients with postmenopausal osteoporosis.

PubMed

Xu, Xiao-juan; Shen, Lin; Yang, Yan-ping; Lu, Fu-rong; Zhu, Rui; Shuai, Bo; Li, Cheng-gang; Wu, Man-xiang

2013-07-01

Sclerostin, expressed exclusively by osteocytes, is a negative regulator of bone formation. To gain insights into the action of sclerostin in postmenopausal osteoporosis, we evaluated serum sclerostin levels in postmenopausal women and investigated its possible associations with bone turnover markers in patients with postmenopausal osteoporosis. We detected serum sclerostin, and measured lumbar spine bone mineral density in 650 Chinese postmenopausal women. We also assessed serum levels of β-isomerized C-terminal crosslinking of type I collagen, intact N-terminal propeptide of type I collagen, N-mid fragment of osteocalcin, 25-hydroxyvitamin D, and estradiol. Serum sclerostin levels were lower in postmenopausal osteoporotic women compared with non-osteoporotic postmenopausal women ((38.79 ± 7.43) vs. (52.86 ± 6.69) pmol/L, P < 0.001). Serum sclerostin was positively correlated with lumbar spine bone mineral density (r = 0.391, P < 0.001) and weakly negatively correlated with β-isomerized C-terminal crosslinking of type I collagen, intact N-terminal propeptide of type I collagen, N-mid fragment of osteocalcin (r = -0.225, P < 0.001; r = -0.091, P = 0.046; r = -0.108, P = 0.018; respectively) in postmenopausal osteoporosis. There was no significant association of serum sclerostin with age, body mass index, 25-hydroxyvitamin D, and estradiol (r = -0.004, P = 0.926; r = 0.067, P = 0.143; r = 0.063, P = 0.165; r = -0.045, P = 0.324; respectively). Sclerostin may be involved in the pathogenesis of postmenopausal osteoporosis and may play a role in bone turnover.

Gamow-Teller Strength Distributions in {sup 48}Sc by the {sup 48}Ca(p,n) and {sup 48}Ti(n,p) Reactions and Two-Neutrino Double-beta Decay Nuclear Matrix Elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yako, K.; Sasano, M.; Miki, K.

2009-07-03

The double-differential cross sections for the {sup 48}Ca(p,n) and {sup 48}Ti(n,p) reactions were measured at 300 MeV. A multipole decomposition technique was applied to the spectra to extract the Gamow-Teller (GT) components. The integrated GT strengths up to an excitation energy of 30 MeV in {sup 48}Sc are 15.3+-2.2 and 2.8+-0.3 in the (p,n) and (n,p) spectra, respectively. In the (n,p) spectra additional GT strengths were found above 8 MeV where shell models within the fp shell-model space predict almost no GT strengths, suggesting that the present shell-model description of the nuclear matrix element of the two-neutrino double-beta decay ismore » incomplete.« less

1-Nitropyrene (1-NP) induces apoptosis and apparently a non-apoptotic programmed cell death (paraptosis) in Hepa1c1c7 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asare, Nana; Landvik, Nina E.; Lagadic-Gossmann, Dominique

2008-07-15

Mechanistic studies of nitro-PAHs (polycyclic aromatic hydrocarbons) of interest might help elucidate which chemical characteristics are most important in eliciting toxic effects. 1-Nitropyrene (1-NP) is the predominant nitrated PAH emitted in diesel exhaust. 1-NP-exposed Hepa1c1c7 cells exhibited marked changes in cellular morphology, decreased proliferation and different forms of cell death. A dramatic increase in cytoplasmic vacuolization was observed already after 6 h of exposure and the cells started to round up at 12 h. The rate of cell proliferation was markedly reduced at 24 h and apoptotic as well as propidium iodide (PI)-positive cells appeared. Electron microscopic examination revealed thatmore » the vacuolization was partly due to mitochondria swelling. The caspase inhibitor Z-VAD-FMK inhibited only the apoptotic cell death and Nec-1 (an inhibitor of necroptosis) exhibited no inhibitory effects on either cell death or vacuolization. In contrast, cycloheximide markedly reduced both the number of apoptotic and PI-positive cells as well as the cytoplasmic vacuolization, suggesting that 1-NP induced paraptotic cell death. All the MAPKs; ERK1/2, p38 and JNK, appear to be involved in the death process since marked activation was observed upon 1-NP exposure, and their inhibitors partly reduced the induced cell death. The ERK1/2 inhibitor PD 98057 completely blocked the induced vacuolization, whereas the other MAPKs inhibitors only had minor effects on this process. These findings suggest that 1-NP may cause apoptosis and paraptosis. In contrast, the corresponding amine (1-aminopyrene) elicited only minor apoptotic and necrotic cell death, and cells with characteristics typical of paraptosis were absent.« less

The TDP-43 N-terminal domain structure at high resolution.

PubMed

Mompeán, Miguel; Romano, Valentina; Pantoja-Uceda, David; Stuani, Cristiana; Baralle, Francisco E; Buratti, Emanuele; Laurents, Douglas V

2016-04-01

Transactive response DNA-binding protein 43 kDa (TDP-43) is an RNA transporting and processing protein whose aberrant aggregates are implicated in neurodegenerative diseases. The C-terminal domain of this protein plays a key role in mediating this process. However, the N-terminal domain (residues 1-77) is needed to effectively recruit TDP-43 monomers into this aggregate. In the present study, we report, for the first time, the essentially complete (1) H, (15) N and (13) C NMR assignments and the structure of the N-terminal domain determined on the basis of 26 hydrogen-bond, 60 torsion angle and 1058 unambiguous NOE structural restraints. The structure consists of an α-helix and six β-strands. Two β-strands form a β-hairpin not seen in the ubiquitin fold. All Pro residues are in the trans conformer and the two Cys are reduced and distantly separated on the surface of the protein. The domain has a well defined hydrophobic core composed of F35, Y43, W68, Y73 and 17 aliphatic side chains. The fold is topologically similar to the reported structure of axin 1. The protein is stable and no denatured species are observed at pH 4 and 25 °C. At 4 kcal·mol(-1) , the conformational stability of the domain, as measured by hydrogen/deuterium exchange, is comparable to ubiquitin (6 kcal·mol(-1) ). The β-strands, α-helix, and three of four turns are generally rigid, although the loop formed by residues 47-53 is mobile, as determined by model-free analysis of the (15) N{(1) H}NOE, as well as the translational and transversal relaxation rates. Structural data have been deposited in the Protein Data Bank under accession code: 2n4p. The NMR assignments have been deposited in the BMRB database under access code: 25675. © 2016 Federation of European Biochemical Societies.

SVM-Based Prediction of Propeptide Cleavage Sites in Spider Toxins Identifies Toxin Innovation in an Australian Tarantula

PubMed Central

Wong, Emily S. W.; Hardy, Margaret C.; Wood, David; Bailey, Timothy; King, Glenn F.

2013-01-01

Spider neurotoxins are commonly used as pharmacological tools and are a popular source of novel compounds with therapeutic and agrochemical potential. Since venom peptides are inherently toxic, the host spider must employ strategies to avoid adverse effects prior to venom use. It is partly for this reason that most spider toxins encode a protective proregion that upon enzymatic cleavage is excised from the mature peptide. In order to identify the mature toxin sequence directly from toxin transcripts, without resorting to protein sequencing, the propeptide cleavage site in the toxin precursor must be predicted bioinformatically. We evaluated different machine learning strategies (support vector machines, hidden Markov model and decision tree) and developed an algorithm (SpiderP) for prediction of propeptide cleavage sites in spider toxins. Our strategy uses a support vector machine (SVM) framework that combines both local and global sequence information. Our method is superior or comparable to current tools for prediction of propeptide sequences in spider toxins. Evaluation of the SVM method on an independent test set of known toxin sequences yielded 96% sensitivity and 100% specificity. Furthermore, we sequenced five novel peptides (not used to train the final predictor) from the venom of the Australian tarantula Selenotypus plumipes to test the accuracy of the predictor and found 80% sensitivity and 99.6% 8-mer specificity. Finally, we used the predictor together with homology information to predict and characterize seven groups of novel toxins from the deeply sequenced venom gland transcriptome of S. plumipes, which revealed structural complexity and innovations in the evolution of the toxins. The precursor prediction tool (SpiderP) is freely available on ArachnoServer (http://www.arachnoserver.org/spiderP.html), a web portal to a comprehensive relational database of spider toxins. All training data, test data, and scripts used are available from the SpiderP

Modulation of follistatin and myostatin propeptide by anabolic steroids and gender.

PubMed

Mosler, S; Geisler, S; Hengevoss, J; Schiffer, T; Piechotta, M; Adler, M; Diel, P

2013-07-01

The purpose of this pilot study was to investigate the impact of training, anabolic steroids and endogenous hormones on myostatin-interacting proteins in order to identify manipulations of myostatin signalling. To identify whether analysis of the myostatin interacting proteins follistatin and myostatin propeptide is suitable to detect the abuse of anabolic steroids, their serum concentrations were monitored in untrained males, bodybuilders using anabolic steroids and natural bodybuilders. In addition, we analysed follistatin and myostatin propeptide serum proteins in females during menstrual cycle. Our results showed increased follistatin concentrations in response to anabolic steroids. Furthermore, variations of sex steroid levels during the menstrual cycle had no impact on the expression of follistatin and myostatin propetide. In addition, we identified gender differences in the basal expression of the investigated proteins. In general, follistatin and myostatin propeptide concentrations were relatively stable within the same individual both in males and females. In conclusion, the current findings provide an insight into gender differences in myostatin-interacting proteins and their regulation in response to anabolic steroids and endogenous hormones. Therefore our data provide new aspects for the development of doping prevention strategies. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of Teriparatide Retreatment in Osteoporotic Men and Women

PubMed Central

Finkelstein, Joel S.; Wyland, Jason J.; Leder, Benjamin Z.; Burnett-Bowie, Sherri-Ann M.; Lee, Hang; Jüppner, Harald; Neer, Robert M.

2009-01-01

Context: The stimulatory effect of teriparatide on bone mineral density (BMD) and bone turnover is initially exuberant, but then diminishes. Objective: Our objective was to determine whether retreating with teriparatide after a drug-free period can restore the initial exuberant response to teriparatide. Design and Setting: This was a planned extension of a randomized controlled trial conducted in a single university hospital. Patients and Intervention: Subjects previously participated in a 30-month randomized trial comparing the effects of alendronate (group 1), teriparatide (group 2), or both (group 3) on BMD and bone turnover in men and women with low BMD (phase 1). Subjects who completed phase 1 on their assigned therapy entered phase 2 (months 30–42), during which teriparatide was stopped in groups 2 and 3. Teriparatide was administered to all subjects during months 42 to 54 (phase 3). Main Outcome Measures: We compared changes in BMD and markers of bone turnover (serum osteocalcin, N-terminal propeptide of type 1 collagen, and N-telopeptide) between phase 1 and 3 in subjects receiving teriparatide alone. Results: Posterior-anterior and lateral spine BMD increased 12.5 ± 1.5 and 16.9 ± 1.7%, respectively, during the first 12 months of teriparatide administration and 5.2 ± 0.8 and 6.2 ± 1.8%, respectively, during teriparatide retreatment (P < 0.001 and P = 0.001). Increases in osteocalcin (P < 0.001), N-terminal propeptide of type 1 collagen (P < 0.001), and N-telopeptide (P < 0.001) were greater during the first period of teriparatide administration. Conclusion: The response to teriparatide is attenuated when readministered after a 12-month hiatus. PMID:19401368

Interplay between ΔNp63 and miR-138-5p regulates growth, metastasis and stemness of oral squamous cell carcinoma

PubMed Central

Zhuang, Zehang; Xie, Nan; Hu, Jing; Yu, Pei; Wang, Cheng; Hu, Xingxue; Han, Xiaozhe; Hou, Jinsong; Huang, Hongzhang; Liu, Xiqiang

2017-01-01

TP63 acts as a master regulator in epithelia development and in the progression of various cancers, but its role in oral cancer pathogenesis remains unknown. This study aimed to explore the role of TP63 in the progression of oral squamous cell carcinoma (OSCC). This study shows that ΔNp63, the predominant isoform of TP63, is significantly upregulated in OSCC tissues and cell lines compared with their normal counterparts, and its expression is closely correlated with pathological differentiation, lymph node metastasis and clinical stage in patients with OSCC. The overexpression of ΔNp63 promotes growth, metastasis and stem-like properties in OSCC cells, and ΔNp63 depletion significantly represses OSCC cellular phenotypes in vitro and in vivo. The ΔNp63 isoform transcriptionally suppresses miR-138-5p expression; restoration of miR-138-5p expression partially abolishes the effect of upregulating ΔNp63. This study also demonstrates that miR-138-5p directly targets ΔNp63, resulting in crosstalk with ΔNp63. The correlation between ΔNp63 and miR-138-5p was further validated in OSCC tissues and was found to be significantly associated with the prognosis of patients with OSCC. Therefore, our data reveal that the interplay between ΔNp63 and miR-138-5p promotes OSCC progression by regulating cell growth, metastasis and stemness. PMID:28423539

Switching from tenofovir to abacavir in HIV-1-infected patients with low bone mineral density: changes in bone turnover markers and circulating sclerostin levels.

PubMed

Negredo, Eugènia; Diez-Pérez, Adolfo; Bonjoch, Anna; Domingo, Pere; Pérez-Álvarez, Núria; Gutierrez, Mar; Mateo, Gracia; Puig, Jordi; Echeverría, Patricia; Escrig, Roser; Clotet, Bonaventura

2015-07-01

Tenofovir is involved in accelerated bone mineral density (BMD) loss. We recently published a hip BMD improvement at week 48 [+2.1% (95% CI: -0.6, 4.7) (P = 0.043)] in HIV-infected patients with osteopenia/osteoporosis randomized to switch from tenofovir to abacavir (n = 26), although without reaching statistical significance compared with those who maintained tenofovir (n = 28). Here, we present changes at week 48 in bone markers [C-terminal telopeptide of collagen type 1 (CTX), osteocalcin and procollagen type 1 N propeptide (P1NP)] as well as in circulating levels of three proteins involved in bone regulation [osteoprotegerin, receptor activator for NF-κB ligand (RANKL) and sclerostin, a selective regulator of bone formation through the Wnt pathway] in 44 of these patients. χ(2) or Fisher and Student t-tests were performed according to the distribution of the variables. Bone markers decreased only in the abacavir group [mean (SD) CTX changed from 0.543 (0.495) to 0.301 (0.306) ng/mL; mean (SD) osteocalcin changed from 23.72 (22.20) to 13.95 (12.40) ng/mL; and mean (SD) P1NP changed from 54.68 (54.52) to 28.65 (27.48) ng/mL (P < 0.001 in all cases)], reaching statistical significance between the groups at week 48. Osteoprotegerin did not vary, but sclerostin significantly increased in the abacavir group [from 29.53 (27.91) to 35.56 (34.59) pmol/L, P = 0.002]. No significant differences in osteoprotegerin and sclerostin were detected between the groups at week 48. RANKL values were below the limit of detection in all samples. The switch from tenofovir to abacavir seems to induce a positive effect on bone tissue, since bone turnover markers decreased. In addition, circulating sclerostin levels increased, a change associated with improved bone properties. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Development of a functional cell-based assay that probes the specific interaction between influenza A virus NP and its packaging signal sequence RNA.

PubMed

Woo, Jiwon; Yu, Kyung Lee; Lee, Sun Hee; You, Ji Chang

2015-02-06

Although cis-acting packaging signal RNA sequences for the influenza virus NP encoding vRNA have been identified recently though genetic studies, little is known about the interaction between NP and the vRNA packaging signals either in vivo or in vitro. Here, we provide evidence that NP is able to interact specifically with the vRNA packaging sequence RNA within living cells and that the specific RNA binding activity of NP in vivo requires both the N-terminal and central region of the protein. This assay established would be a valuable tool for further detailed studies of the NP-packaging signal RNA interaction in living cells. Copyright © 2014 Elsevier Inc. All rights reserved.

Np9, a cellular protein of retroviral ancestry restricted to human, chimpanzee and gorilla, binds and regulates ubiquitin ligase MDM2

PubMed Central

Heyne, Kristina; Kölsch, Kathrin; Bruand, Marine; Kremmer, Elisabeth; Grässer, Friedrich A; Mayer, Jens; Roemer, Klaus

2015-01-01

Humans and primates are long-lived animals with long reproductive phases. One factor that appears to contribute to longevity and fertility in humans, as well as to cancer-free survival, is the transcription factor and tumor suppressor p53, controlled by its main negative regulator MDM2. However, p53 and MDM2 homologs are found throughout the metazoan kingdom from Trichoplacidae to Hominidae. Therefore the question arises, if p53/MDM2 contributes to the shaping of primate features, then through which mechanisms. Previous findings have indicated that the appearances of novel p53-regulated genes and wild-type p53 variants during primate evolution are important in this context. Here, we report on another mechanism of potential relevance. Human endogenous retrovirus K subgroup HML-2 (HERV-K(HML-2)) type 1 proviral sequences were formed in the genomes of the predecessors of contemporary Hominoidea and can be identified in the genomes of Nomascus leucogenys (gibbon) up to Homo sapiens. We previously reported on an alternative splicing event in HERV-K(HML-2) type 1 proviruses that can give rise to nuclear protein of 9 kDa (Np9). We document here the evolution of Np9-coding capacity in human, chimpanzee and gorilla, and show that the C-terminal half of Np9 binds directly to MDM2, through a domain of MDM2 that is known to be contacted by various cellular proteins in response to stress. Np9 can inhibit the MDM2 ubiquitin ligase activity toward p53 in the cell nucleus, and can support the transactivation of genes by p53. Our findings point to the possibility that endogenous retrovirus protein Np9 contributes to the regulation of the p53-MDM2 pathway specifically in humans, chimpanzees and gorillas. PMID:26103464

Influence of the N-terminal peptide on the cocrystallization of a thermophilic endo-β-1,4-glucanase with polysaccharide substrates.

PubMed

Zheng, Baisong; Yang, Wen; Wang, Yuguo; Lou, Zhiyong; Feng, Yan

2011-10-01

It is well known that protein cocrystallization is affected by several parameters such as the ratio of the protein to the ligand, the reservoir solution, the pH and the temperature. Previously, spatial blocking by the N-terminus was observed in the active site in the crystal structure of the native protein of a thermostable endoglucanase from the thermophilic bacterium Fervidobacterium nodosum Rt17-B1 (FnCel5A). It was speculated that the N-terminal α-helix might form interactions with the substrate-binding residues and it was believed that this spatial block is special to some extent. In order to confirm the effect on cocrystallization, two N-terminally truncated variants of FnCel5A were constructed, purified and cocrystallized at 291 K. A crystal of FnCel5AND_12-343 in complex with cellobiose was obtained using PEG 8000 as a precipitant. A 2.2 Å resolution data set was collected. This crystal form (space group P4(1)2(1)2, unit-cell parameters a = b = 47.3, c = 271.4 Å) differed from that of the native protein. One molecule is assumed to be present per asymmetric unit, which gives a Matthews coefficient of 2.05 Å(3) Da(-1). © 2011 International Union of Crystallography. All rights reserved.

Regulation of the p73 protein stability and degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oberst, Andrew; Rossi, Mario; Salomoni, Paolo

2005-06-10

p73, a homologue to the tumor suppressor gene p53, is involved in tumorigenesis, though its specific role remains unclear. The gene has two distinct promoters which allow the formation of two protein isoforms with opposite effects: full-length transactivating (TA) p73 shows pro-apoptotic effects, while the shorter {delta}Np73, which lacks the N-terminal transactivating domain, has an evident anti-apoptotic function. Unlike p53, the p73 gene is rarely mutated in human cancers. However, alterations in the relative levels of TA and {delta}Np73 have been shown to correlate with prognosis in several human cancers, suggesting that the fine regulation of these two isoforms ismore » of pivotal importance in controlling proliferation and cell death. Much effort is currently focused on the elucidation of the mechanisms that differentially control TA and {delta}Np73 activity and protein stability, a process complicated by the finding that both proteins are regulated by a similar suite of complex post-translational modifications that include ubiquitination, sequential phosphorylation, prolyl-isomerization, recruitment into the PML-nuclear body (PML-NB), and acetylation. Here we shall consider the main regulatory partners of p73, with particular attention to the recently discovered Itch- and Nedd8-mediated degradation pathways, along with the emerging roles of PML, p38 MAP kinase, Pin1, and p300 in p73 transcriptional activation, and possible mechanisms for the differential regulation of the TAp73 and {delta}Np73 isoforms.« less

No association between the vitamin D pathway gene polymorphisms and bone biomarkers response to calcium and low dose calcitriol supplementation in postmenopausal Chinese women: a one-year prospective study.

PubMed

Gu, Jiemei; Wang, Chun; Zhang, Hao; Yue, Hua; Hu, Weiwei; He, Jinwei; Fu, Wenzhen; Zhang, Zhenlin

2018-05-18

The aim of the study was to explore the association between the vitamin D pathway gene variations and the bone biomarkers response to calcium and low dose calcitriol supplementation in postmenopausal Chinese women. A total of 110 healthy postmenopausal Chinese women (61.51 ± 6.93 years) were enrolled. The participants were supplemented with calcium (600 mg/d) and calcitriol (0.25 μg/d), for 1 year. Four biomarkers, serum levels of beta C-terminal cross-linked telopeptides of type I collagen (β-CTX), amino-terminal propeptide of type I collagen (P1NP), parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] were measured at baseline and 12-month follow-up. Multivariate regression models were established to explore the statistical association between the change rate of the four biomarkers and 15 key genes within the vitamin D metabolic pathway. This exclusion process left 98 participants for analysis. Serum levels of P1NP, β-CTX and PTH were significantly decreased at the 12-month follow-up (all p < 0.05). Serum 25(OH)D level had no significant change (p > 0.05). No association was found between the vitamin D pathway gene polymorphisms and bone biomarkers response to calcium and low dose calcitriol supplementation. Genetic background of postmenopausal Chinese women might not influence supplemental response of the biomarkers to calcium and low dose calcitriol.

Arc1p is required for cytoplasmic confinement of synthetases and tRNA.

PubMed

Golinelli-Cohen, Marie-Pierre; Mirande, Marc

2007-06-01

In yeast, Arc1p interacts with ScMetRS and ScGluRS and operates as a tRNA-Interacting Factor (tIF) in trans of these two synthetases. Its N-terminal domain (N-Arc1p) binds the two synthetases and its C-terminal domain is an EMAPII-like domain organized around an OB-fold-based tIF. ARC1 is not an essential gene but its deletion (arc1- cells) is accompanied by a growth retardation phenotype. Here, we show that expression of N-Arc1p or of C-Arc1p alone palliates the growth defect of arc1- cells, and that bacterial Trbp111 or human p43, two proteins containing EMAPII-like domains, also improve the growth of an arc1- strain. The synthetic lethality of an arc1-los1- strain can be complemented with either ARC1 or LOS1. Expression of N-Arc1p or C-Arc1p alone does not complement an arc1-los1- phenotype, but coexpression of the two domains does. Our data demonstrate that Trbp111 or p43 may replace C-Arc1p to complement an arc1-los1- strain. The two functional domains of Arc1p (N-Arc1p and C-Arc1p) are required to get rid of the synthetic lethal phenotype but do not need to be physically linked. To get some clues to the discrete functions of N-Arc1p and C-Arc1p, we targeted ScMetRS or tIF domains to the nuclear compartment and analyzed their cellular localization by using GFP fusions, and their ability to sustain growth. Our results are consistent with a model according to which Arc1p is a bifunctional protein involved in the subcellular localization of ScMetRS and ScGluRS via its N-terminal domain and of tRNA via its C-terminal domain.

Purification and biochemical characterization of NpABCG5/NpPDR5, a plant pleiotropic drug resistance transporter expressed in Nicotiana tabacum BY-2 suspension cells.

PubMed

Toussaint, Frédéric; Pierman, Baptiste; Bertin, Aurélie; Lévy, Daniel; Boutry, Marc

2017-05-04

Pleiotropic drug resistance (PDR) transporters belong to the ABCG subfamily of ATP-binding cassette (ABC) transporters and are involved in the transport of various molecules across plasma membranes. During evolution, PDR genes appeared independently in fungi and in plants from a duplication of a half-size ABC gene. The enzymatic properties of purified PDR transporters from yeast have been characterized. This is not the case for any plant PDR transporter, or, incidentally, for any purified plant ABC transporter. Yet, plant PDR transporters play important roles in plant physiology such as hormone signaling or resistance to pathogens or herbivores. Here, we describe the expression, purification, enzymatic characterization and 2D analysis by electron microscopy of NpABCG5/NpPDR5 from Nicotiana plumbaginifolia , which has been shown to be involved in the plant defense against herbivores. We constitutively expressed NpABCG5/NpPDR5, provided with a His-tag in a homologous system: suspension cells from Nicotiana tabacum (Bright Yellow 2 line). NpABCG5/NpPDR5 was targeted to the plasma membrane and was solubilized by dodecyl maltoside and purified by Ni-affinity chromatography. The ATP-hydrolyzing specific activity (27 nmol min -1  mg -1 ) was stimulated seven-fold in the presence of 0.1% asolectin. Electron microscopy analysis indicated that NpABCG5/NpPDR5 is monomeric and with dimensions shorter than those of known ABC transporters. Enzymatic data (optimal pH and sensitivity to inhibitors) confirmed that plant and fungal PDR transporters have different properties. These data also show that N. tabacum suspension cells are a convenient host for the purification and biochemical characterization of ABC transporters. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Interactions and Nuclear Import of the N and P Proteins of Sonchus Yellow Net Virus, a Plant Nucleorhabdovirus

PubMed Central

Goodin, Michael M.; Austin, Jennifer; Tobias, Renée; Fujita, Miki; Morales, Christina; Jackson, Andrew O.

2001-01-01

We have characterized the interaction and nuclear localization of the nucleocapsid (N) protein and phosphoprotein (P) of sonchus yellow net nucleorhabdovirus. Expression studies with plant and yeast cells revealed that both N and P are capable of independent nuclear import. Site-specific mutagenesis and deletion analyses demonstrated that N contains a carboxy-terminal bipartite nuclear localization signal (NLS) located between amino acids 465 and 481 and that P contains a karyophillic region between amino acids 40 and 124. The N NLS was fully capable of functioning outside of the context of the N protein and was able to direct the nuclear import of a synthetic protein fusion consisting of green fluorescent protein fused to glutathione S-transferase (GST). Expression and mapping studies suggested that the karyophillic domain in P is located within the N-binding domain. Coexpression of N and P drastically affected their localization patterns relative to those of individually expressed proteins and resulted in a shift of both proteins to a subnuclear region. Yeast two-hybrid and GST pulldown experiments verified the N-P and P-P interactions, and deletion analyses have identified the N and P interacting domains. N NLS mutants were not transported to the nucleus by import-competent P, presumably because N binding masks the P NLS. Taken together, our results support a model for independent entry of N and P into the nucleus followed by associations that mediate subnuclear localization. PMID:11533202

Identification of NpO2+x in the binary Np-O system

NASA Astrophysics Data System (ADS)

Tayal, Akhil; Conradson, Steven D.; Baldinozzi, Gianguido; Namdeo, Sonu; Roberts, Kevin E.; Allen, Patrick G.; Shuh, David K.

2017-07-01

In contrast to UO2 and PuO2, there is no consensus on the existence of mixed valence NpO2+x, resulting in a gap between NpO2 and Np2O5 (the highest binary oxide of Np) in the Np-O phase diagram. We now show NpO2+x via Np LIII Extended X-ray Absorption Fine Structure (EXAFS) spectra of three samples of NpO2 that, analogous to U and Pu, exhibit multisite Np-O distributions with varying numbers of oxygen atoms at 1.87-1.91 Å. This is supported by the diffraction pattern of the sample with the largest amount of this oxo-type species that can be refined with both the simple fluorite structure and a trigonal one related to α-U4O9. The implied Np(V)-bridging oxo moieties as well as possible indications of OHbar found by detailed EXAFS analysis suggest that NpO2+x more closely resembles PuO2+x than UO2+x. An additional common characteristic suggested by the EXAFS and X-Ray Diffraction (XRD) is the phase separation into NpO2 and what would be previously unreported Np4O9(-δ), indicative of O clustering.

N-terminal domain of the dual-targeted pea glutathione reductase signal peptide controls organellar targeting efficiency.

PubMed

Rudhe, Charlotta; Clifton, Rachel; Whelan, James; Glaser, Elzbieta

2002-12-06

Import of nuclear-encoded proteins into mitochondria and chloroplasts is generally organelle specific and its specificity depends on the N-terminal signal peptide. Yet, a group of proteins known as dual-targeted proteins have a targeting peptide capable of leading the mature protein to both organelles. We have investigated the domain structure of the dual-targeted pea glutathione reductase (GR) signal peptide by using N-terminal truncations. A mutant of the GR precursor (pGR) starting with the second methionine residue of the targeting peptide, pGRdelta2-4, directed import into both organelles, negating the possibility that dual import was controlled by the nature of the N terminus. The deletion of the 30 N-terminal residues (pGRdelta2-30) inhibited import efficiency into chloroplasts substantially and almost completely into mitochondria, whereas the removal of only 16 N-terminal amino acid residues (pGRdelta2-16) resulted in the strongly stimulated mitochondrial import without significantly affecting chloroplast import. Furthermore, N-terminal truncations of the signal peptide (pGRdelta2-16 and pGRdelta2-30) greatly stimulated the mitochondrial processing activity measured with the isolated processing peptidase. These results suggest a domain structure for the dual-targeting peptide of pGR and the existence of domains controlling organellar import efficiency therein.

Identification of C-terminal phosphorylation sites of N-formyl peptide receptor-1 (FPR1) in human blood neutrophils.

PubMed

Maaty, Walid S; Lord, Connie I; Gripentrog, Jeannie M; Riesselman, Marcia; Keren-Aviram, Gal; Liu, Ting; Dratz, Edward A; Bothner, Brian; Jesaitis, Algirdas J

2013-09-20

Accumulation, activation, and control of neutrophils at inflammation sites is partly driven by N-formyl peptide chemoattractant receptors (FPRs). Occupancy of these G-protein-coupled receptors by formyl peptides has been shown to induce regulatory phosphorylation of cytoplasmic serine/threonine amino acid residues in heterologously expressed recombinant receptors, but the biochemistry of these modifications in primary human neutrophils remains relatively unstudied. FPR1 and FPR2 were partially immunopurified using antibodies that recognize both receptors (NFPRa) or unphosphorylated FPR1 (NFPRb) in dodecylmaltoside extracts of unstimulated and N-formyl-Met-Leu-Phe (fMLF) + cytochalasin B-stimulated neutrophils or their membrane fractions. After deglycosylation and separation by SDS-PAGE, excised Coomassie Blue-staining bands (∼34,000 Mr) were tryptically digested, and FPR1, phospho-FPR1, and FPR2 content was confirmed by peptide mass spectrometry. C-terminal FPR1 peptides (Leu(312)-Arg(322) and Arg(323)-Lys(350)) and extracellular FPR1 peptide (Ile(191)-Arg(201)) as well as three similarly placed FPR2 peptides were identified in unstimulated and fMLF + cytochalasin B-stimulated samples. LC/MS/MS identified seven isoforms of Ala(323)-Lys(350) only in the fMLF + cytochalasin B-stimulated sample. These were individually phosphorylated at Thr(325), Ser(328), Thr(329), Thr(331), Ser(332), Thr(334), and Thr(339). No phospho-FPR2 peptides were detected. Cytochalasin B treatment of neutrophils decreased the sensitivity of fMLF-dependent NFPRb recognition 2-fold, from EC50 = 33 ± 8 to 74 ± 21 nM. Our results suggest that 1) partial immunopurification, deglycosylation, and SDS-PAGE separation of FPRs is sufficient to identify C-terminal FPR1 Ser/Thr phosphorylations by LC/MS/MS; 2) kinases/phosphatases activated in fMLF/cytochalasin B-stimulated neutrophils produce multiple C-terminal tail FPR1 Ser/Thr phosphorylations but have little effect on corresponding FPR2 sites

Bean peptides have higher in silico binding affinities than ezetimibe for the N-terminal domain of cholesterol receptor Niemann-Pick C1 Like-1.

PubMed

Real Hernandez, Luis M; Gonzalez de Mejia, Elvira

2017-04-01

Niemann-Pick C1 like-1 (NPC1L1) mediates cholesterol absorption at the apical membrane of enterocytes through a yet unknown mechanism. Bean, pea, and lentil proteins are naturally hydrolyzed during digestion to produce peptides. The potential for pulse peptides to have high binding affinities for NPC1L1 has not been determined. In this study , in silico binding affinities and interactions were determined between the N-terminal domain of NPC1L1 and 14 pulse peptides (5≥ amino acids) derived through pepsin-pancreatin digestion. Peptides were docked in triplicate to the N-terminal domain using docking program AutoDock Vina, and results were compared to those of ezetimibe, a prescribed NPC1L1 inhibitor. Three black bean peptides (-7.2 to -7.0kcal/mol) and the cowpea bean dipeptide Lys-Asp (-7.0kcal/mol) had higher binding affinities than ezetimibe (-6.6kcal/mol) for the N-terminal domain of NPC1L1. Lentil and pea peptides studied did not have high binding affinities. The common bean peptide Tyr-Ala-Ala-Ala-Thr (-7.2kcal/mol), which can be produced from black or navy bean proteins, had the highest binding affinity. Ezetimibe and peptides with high binding affinities for the N-terminal domain are expected to interact at different locations of the N-terminal domain. All high affinity black bean peptides are expected to have van der Waals interactions with SER130, PHE136, and LEU236 and a conventional hydrogen bond with GLU238 of NPC1L1. Due to their high affinity for the N-terminal domain of NPC1L1, black and cowpea bean peptides produced in the digestive track have the potential to disrupt interactions between NPC1L1 and membrane proteins that lead to cholesterol absorption. Copyright © 2017 Elsevier Inc. All rights reserved.

Influence of the N-terminal peptide on the cocrystallization of a thermophilic endo-β-1,4-glucanase with polysaccharide substrates

PubMed Central

Zheng, Baisong; Yang, Wen; Wang, Yuguo; Lou, Zhiyong; Feng, Yan

2011-01-01

It is well known that protein cocrystallization is affected by several parameters such as the ratio of the protein to the ligand, the reservoir solution, the pH and the temperature. Previously, spatial blocking by the N-terminus was observed in the active site in the crystal structure of the native protein of a thermostable endoglucanase from the thermophilic bacterium Fervidobacterium nodosum Rt17-B1 (FnCel5A). It was speculated that the N-terminal α-helix might form interactions with the substrate-binding residues and it was believed that this spatial block is special to some extent. In order to confirm the effect on cocrystallization, two N-terminally truncated variants of FnCel5A were constructed, purified and cocrystallized at 291 K. A crystal of FnCel5AND_12–343 in complex with cellobiose was obtained using PEG 8000 as a precipitant. A 2.2 Å resolution data set was collected. This crystal form (space group P41212, unit-cell parameters a = b = 47.3, c = 271.4 Å) differed from that of the native protein. One molecule is assumed to be present per asymmetric unit, which gives a Matthews coefficient of 2.05 Å3 Da−1. PMID:22102031

E-Peptides Control Bioavailability of IGF-1

PubMed Central

Piszczek, Agnieszka; Perlas, Emarald; Winn, Nadine; Nastasi, Tommaso; Rosenthal, Nadia

2012-01-01

Insulin-like growth factor 1 (IGF-1) is a potent cytoprotective growth factor that has attracted considerable attention as a promising therapeutic agent. Transgenic over-expression of IGF-1 propeptides facilitates protection and repair in a broad range of tissues, although transgenic mice over-expressing IGF-1 propeptides display little or no increase in IGF-1 serum levels, even with high levels of transgene expression. IGF-1 propeptides are encoded by multiple alternatively spliced transcripts including C-terminal extension (E) peptides, which are highly positively charged. In the present study, we use decellularized mouse tissue to show that the E-peptides facilitate in vitro binding of murine IGF-1 to the extracellular matrix (ECM) with varying affinities. This property is independent of IGF-1, since proteins consisting of the E-peptides fused to relaxin, a related member of the insulin superfamily, bound equally avidly to decellularized ECM. Thus, the E-peptides control IGF-1 bioavailability by preventing systemic circulation, offering a potentially powerful way to tether IGF-1 and other therapeutic proteins to the site of synthesis and/or administration. PMID:23251442

Retention of Chs2p in the ER requires N-terminal CDK1-phosphorylation sites.

PubMed

Teh, Ee Mei; Chai, Chuan Chung; Yeong, Foong May

2009-09-15

In budding yeast, the secretory pathway is constitutively transporting cargoes such as invertase and alpha-factor throughout the cell division cycle. However, chitin synthase 2 (Chs2p), another cargo of the secretory pathway, is retained at the endoplasmic reticulum (ER) during mitosis when the mitotic kinase activity is high. Chs2p is exported from the ER to the mother-daughter neck only upon mitotic kinase destruction, indicating that the mitotic kinase activity is critical for the ER retention of Chs2p. However, a key question is whether the mitotic kinase acts directly upon Chs2p to prevent its ER export. We report here that mutation of Ser residues to Glu at 4 perfect CDK1-phosphorylation sites at the N-terminus of Chs2p leads to its retention in the ER when the mitotic kinase activity is absent. Conversely, Ser-to-Ala mutations result in the loss of Chs2p ER retention even when mitotic kinase activity is high. The mere overexpression of the non-destructible form of the mitotic cyclin in G(1) cells can confine the wild-type Chs2p but not the Ser-to-Ala mutant in the ER. Furthermore, overexpression of the Ser-to-Ala mutant kills cells. Time-lapsed imaging revealed that Chs2p is exported from the ER rapidly and synchronously to the Golgi upon metaphase release. Our data indicate that direct phosphorylation of Chs2p by the mitotic CDK1 helps restrain it in the ER during mitosis to prevent its rapid export in an untimely manner until after sister chromatid occurs and mitotic exit executed.

The diagnostic value of plasma N-terminal connective tissue growth factor levels in children with heart failure.

PubMed

Li, Gang; Song, Xueqing; Xia, Jiyi; Li, Jing; Jia, Peng; Chen, Pengyuan; Zhao, Jian; Liu, Bin

2017-01-01

The aim of this study was to assess the diagnostic value of plasma N-terminal connective tissue growth factor in children with heart failure. Methods and results Plasma N-terminal connective tissue growth factor was determined in 61 children, including 41 children with heart failure, 20 children without heart failure, and 30 healthy volunteers. The correlations between plasma N-terminal connective tissue growth factor levels and clinical parameters were investigated. Moreover, the diagnostic value of N-terminal connective tissue growth factor levels was evaluated. Compared with healthy volunteers and children without heart failure, plasma N-terminal connective tissue growth factor levels were significantly elevated in those with heart failure (p0.05), but it obviously improved the ability of diagnosing heart failure in children, as demonstrated by the integrated discrimination improvement (6.2%, p=0.013) and net re-classification improvement (13.2%, p=0.017) indices. Plasma N-terminal connective tissue growth factor is a promising diagnostic biomarker for heart failure in children.

N-terminal galanin-(1-16) fragment is an agonist at the hippocampal galanin receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisone, G.; Berthold, M.; Bedecs, K.

1989-12-01

The galanin N-terminal fragment (galanin-(1-16)) has been prepared by solid-phase synthesis and by enzymic cleavage of galanin by endoproteinase Asp-N. This peptide fragment displaced {sup 125}I-labeled galanin in receptor autoradiography experiments on rat forebrain and spinal cord and in equilibrium binding experiments from high-affinity binding sites in the ventral hippocampus with an IC50 of approximately 3 nM. In tissue slices of the same brain area, galanin-(1-16), similarly to galanin, inhibited the muscarinic agonist-stimulated breakdown of inositol phospholipids. Upon intracerebroventricular administration, galanin-(1-16) (10 micrograms/15 microliters) also inhibited the scopolamine (0.3 mg/kg, s.c.)-evoked release of acetylcholine, as studied in vivo by microdialysis.more » Substitution of (L-Trp2) for (D-Trp2) resulted in a 500-fold loss in affinity as compared with galanin-(1-16). It is concluded that, in the ventral hippocampus, the N-terminal galanin fragment (galanin-(1-16)) is recognized by the galanin receptors controlling acetylcholine release and muscarinic agonist-stimulated inositol phospholipid breakdown as a high-affinity agonist and that amino acid residue (Trp2) plays an important role in the receptor-ligand interactions.« less

Photoconductivity of few-layered p-WSe2 phototransistors via multi-terminal measurements

NASA Astrophysics Data System (ADS)

Pradhan, Nihar R.; Garcia, Carlos; Holleman, Joshua; Rhodes, Daniel; Parker, Chason; Talapatra, Saikat; Terrones, Mauricio; Balicas, Luis; McGill, Stephen A.

2016-12-01

Recently, two-dimensional materials and in particular transition metal dichalcogenides (TMDs) have been extensively studied because of their strong light-matter interaction and the remarkable optoelectronic response of their field-effect transistors (FETs). Here, we report a photoconductivity study from FETs built from few-layers of p-WSe2 measured in a multi-terminal configuration under illumination by a 532 nm laser source. The photogenerated current was measured as a function of the incident optical power, of the drain-to-source bias and of the gate voltage. We observe a considerably larger photoconductivity when the phototransistors were measured via a four-terminal configuration when compared to a two-terminal one. For an incident laser power of 248 nW, we extract 18 A W-1 and ˜4000% for the two-terminal responsivity (R) and the concomitant external quantum efficiency (EQE) respectively, when a bias voltage V ds = 1 V and a gate voltage V bg = 10 V are applied to the sample. R and EQE are observed to increase by 370% to ˜85 A W-1 and ˜20 000% respectively, when using a four-terminal configuration. Thus, we conclude that previous reports have severely underestimated the optoelectronic response of transition metal dichalcogenides, which in fact reveals a remarkable potential for photosensing applications.

Study of np{sup 2}P{sub 1/2,3/2} Rydberg series of AlI by the method of laser stepwise excitation and ionization by electric field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasimov, A.K.; Tursunov, A.T.; Tukhlibaev, O.

Frequencies of the 4s{sup 2}S{sub 1/2}-np{sup 2}P{sub 1/2, 3/2} transitions are measured and the energies of high-lying P states, as well as the ionization energy of aluminum atoms, are determined by the method of two-step laser excitation and ionization of excited atoms of AlI by an electric field. 4 refs., 3 figs., 1 tab.

Formation of pyroglutamic acid from N-terminal glutamic acid in immunoglobulin gamma antibodies.

PubMed

Chelius, Dirk; Jing, Kay; Lueras, Alexis; Rehder, Douglas S; Dillon, Thomas M; Vizel, Alona; Rajan, Rahul S; Li, Tiansheng; Treuheit, Michael J; Bondarenko, Pavel V

2006-04-01

The status of the N-terminus of proteins is important for amino acid sequencing by Edman degradation, protein identification by shotgun and top-down techniques, and to uncover biological functions, which may be associated with modifications. In this study, we investigated the pyroglutamic acid formation from N-terminal glutamic acid residues in recombinant monoclonal antibodies. Almost half the antibodies reported in the literature contain a glutamic acid residue at the N-terminus of the light or the heavy chain. Our reversed-phase high-performance liquid chromatography-mass spectrometry method could separate the pyroglutamic acid-containing light chains from the native light chains of reduced and alkylated recombinant monoclonal antibodies. Tryptic peptide mapping and tandem mass spectrometry of the reduced and alkylated proteins was used for the identification of the pyroglutamic acid. We identified the formation of pyroglutamic acid from N-terminal glutamic acid in the heavy chains and light chains of several antibodies, indicating that this nonenzymatic reaction does occur very commonly and can be detected after a few weeks of incubation at 37 and 45 degrees C. The rate of this reaction was measured in several aqueous buffers with different pH values, showing minimal formation of pyroglutamic acid at pH 6.2 and increased formation of pyroglutamic acid at pH 4 and pH 8. The half-life of the N-terminal glutamic acid was approximately 9 months in a pH 4.1 buffer at 45 degrees C. To our knowledge, we showed for the first time that glutamic acid residues located at the N-terminus of proteins undergo pyroglutamic acid formation in vitro.

Protective Efficacy of the Conserved NP, PB1, and M1 Proteins as Immunogens in DNA- and Vaccinia Virus-Based Universal Influenza A Virus Vaccines in Mice

PubMed Central

Wang, Wenling; Li, Renqing; Deng, Yao; Lu, Ning; Chen, Hong; Meng, Xin; Wang, Wen; Wang, Xiuping; Yan, Kexia; Qi, Xiangrong; Zhang, Xiangmin; Xin, Wei; Lu, Zhenhua; Li, Xueren; Bian, Tao; Gao, Yingying; Tan, Wenjie

2015-01-01

The conventional hemagglutinin (HA)- and neuraminidase (NA)-based influenza vaccines need to be updated most years and are ineffective if the glycoprotein HA of the vaccine strains is a mismatch with that of the epidemic strain. Universal vaccines targeting conserved viral components might provide cross-protection and thus complement and improve conventional vaccines. In this study, we generated DNA plasmids and recombinant vaccinia viruses expressing the conserved proteins nucleoprotein (NP), polymerase basic 1 (PB1), and matrix 1 (M1) from influenza virus strain A/Beijing/30/95 (H3N2). BALB/c mice were immunized intramuscularly with a single vaccine based on NP, PB1, or M1 alone or a combination vaccine based on all three antigens and were then challenged with lethal doses of the heterologous influenza virus strain A/PR/8/34 (H1N1). Vaccines based on NP, PB1, and M1 provided complete or partial protection against challenge with 1.7 50% lethal dose (LD50) of PR8 in mice. Of the three antigens, NP-based vaccines induced protection against 5 LD50 and 10 LD50 and thus exhibited the greatest protective effect. Universal influenza vaccines based on the combination of NP, PB1, and M1 induced a strong immune response and thus might be an alternative approach to addressing future influenza virus pandemics. PMID:25834017

Substitutions of PrP N-terminal histidine residues modulate scrapie disease pathogenesis and incubation time in transgenic mice

PubMed Central

Eigenbrod, Sabina; Frick, Petra; Bertsch, Uwe; Mitteregger-Kretzschmar, Gerda; Mielke, Janina; Maringer, Marko; Piening, Niklas; Hepp, Alexander; Daude, Nathalie; Windl, Otto; Levin, Johannes; Giese, Armin; Sakthivelu, Vignesh; Tatzelt, Jörg

2017-01-01

Prion diseases have been linked to impaired copper homeostasis and copper induced-oxidative damage to the brain. Divalent metal ions, such as Cu2+ and Zn2+, bind to cellular prion protein (PrPC) at octapeptide repeat (OR) and non-OR sites within the N-terminal half of the protein but information on the impact of such binding on conversion to the misfolded isoform often derives from studies using either OR and non-OR peptides or bacterially-expressed recombinant PrP. Here we created new transgenic mouse lines expressing PrP with disrupted copper binding sites within all four histidine-containing OR's (sites 1–4, H60G, H68G, H76G, H84G, "TetraH>G" allele) or at site 5 (composed of residues His-95 and His-110; "H95G" allele) and monitored the formation of misfolded PrP in vivo. Novel transgenic mice expressing PrP(TetraH>G) at levels comparable to wild-type (wt) controls were susceptible to mouse-adapted scrapie strain RML but showed significantly prolonged incubation times. In contrast, amino acid replacement at residue 95 accelerated disease progression in corresponding PrP(H95G) mice. Neuropathological lesions in terminally ill transgenic mice were similar to scrapie-infected wt controls, but less severe. The pattern of PrPSc deposition, however, was not synaptic as seen in wt animals, but instead dense globular plaque-like accumulations of PrPSc in TgPrP(TetraH>G) mice and diffuse PrPSc deposition in (TgPrP(H95G) mice), were observed throughout all brain sections. We conclude that OR and site 5 histidine substitutions have divergent phenotypic impacts and that cis interactions between the OR region and the site 5 region modulate pathogenic outcomes by affecting the PrP globular domain. PMID:29220360

Identification of swine H1N2/pandemic H1N1 reassortant influenza virus in pigs, United States.

PubMed

Ali, Ahmed; Khatri, Mahesh; Wang, Leyi; Saif, Yehia M; Lee, Chang-Won

2012-07-06

In October and November 2010, novel H1N2 reassortant influenza viruses were identified from pigs showing mild respiratory signs that included cough and depression. Sequence and phylogenetic analysis showed that the novel H1N2 reassortants possesses HA and NA genes derived from recent H1N2 swine isolates similar to those isolated from Midwest. Compared to the majority of reported reassortants, both viruses preserved human-like host restrictive and putative antigenic sites in their HA and NA genes. The four internal genes, PB2, PB1, PA, and NS were similar to the contemporary swine triple reassortant viruses' internal genes (TRIG). Interestingly, NP and M genes of the novel reassortants were derived from the 2009 pandemic H1N1. The NP and M proteins of the two isolates demonstrated one (E16G) and four (G34A, D53E, I109T, and V313I) amino acid changes in the M2 and NP proteins, respectively. Similar amino acid changes were also noticed upon incorporation of the 2009 pandemic H1N1 NP in other reassortant viruses reported in the U.S. Thus the role of those amino acids in relation to host adaptation need to be further investigated. The reassortments of pandemic H1N1 with swine influenza viruses and the potential of interspecies transmission of these reassortants from swine to other species including human indicate the importance of systematic surveillance of swine population to determine the origin, the prevalence of similar reassortants in the U.S. and their impact on both swine production and public health. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of Liposome, Heat-Killed Mycobacterium w, and Alum Adjuvants in the Protection Offered by Different Combinations of Recombinant HA, NP proteins, and M2e Against Homologous H5N1 Virus.

PubMed

Ingle, Nilesh B; Virkar, Rashmi G; Agnihotri, Kalpana; Sharma, Kapil S; Lole, Kavita S; Arankalle, Vidya A

2016-10-01

Continued evolution of highly pathogenic H5N1 viruses causing high mortality in humans obviates need for broadly cross-reactive vaccines. For this, hemagglutinin (HA) inducing specific protective antibodies, highly conserved nucleoprotein (NP), and ectodomain of matrix (M2e) protein, either singly or in combination, were evaluated in BALB/c mice. Recombinant HA and NP (baculovirus system) and M2e (synthetic peptide) and 3 adjuvants, that is, liposomes, Mw (heat killed Mycobacterium w), and alum were utilized for the homologous virus challenge. Additional immunogens included liposome-encapsulated HA/NP proteins and corresponding DNAs. Mice groups received two doses of respective formulations given at 3-week intervals and challenged intranasally with 100LD50 of H5N1 virus strain. Dynamics of weight loss, lung viral load, titres of IgG-anti-HA, NP, and M2e antibodies (ELISA), and IgG-subtype analysis was done. Two doses of all the formulations led to 100% seroconversion against the immunogens evaluated (100% seroconversion after the first dose in majority). Antibody titres against the components were dependent on the adjuvant and combination. HA-driven Th2 response with all the adjuvants, balanced Th1/Th2 response to NP protein, and Th2-bias with alum were noted. Low anti-M2e antibody titres did not allow subtype analysis. On challenge, complete protection was observed with Mw-HA, alum-HA+NP, Lipo-HA+NP+M2e, alum-HA+NP+M2e, and HA-DP formulations with 12-fold, 8-fold, 720-fold, 17-fold, and no reduction, respectively, in lung viral load. In conclusion, the results identify several adjuvant-immunogen combinations conferring 100% protection in mice that need further evaluation in higher animals.