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1

The interaction of calcium and strontium with phosphatidyl serine in the anaphylactic secretion of histamine  

PubMed Central

1. Spontaneous histamine release from isolated mast cells was found to be independent of calcium in the concentration range up to 1 m-mole/l. Phosphatidyl serine did not change the effect of calcium on spontaneous release. 2. Spontaneous histamine release was found to vary with the strontium ion concentration. Graded increase in the release occurred as the concentration of strontium was raised from 1 to 10 m-mole/l. Phosphatidyl serine potentiated this action of strontium; the potentiation showed a graded increase as the phosphatidyl serine concentration was raised from 1 to 100 ?g/ml. 3. The activation of anaphylactic histamine release by calcium was potentiated by phosphatidyl serine; the degree of potentiation showed a graded increase as the calcium concentration was raised from 0·1 to 1·0 m-mole/l. 4. The activation of anaphylactic histamine release by strontium showed little, if any, potentiation by phosphatidyl serine. 5. The response of the mast cells, in terms of anaphylactic histamine release, to calcium, in the presence of optimal concentrations of phosphatidyl serine, was found to be similar to that observed in the presence of strontium alone. 6. These observations are discussed in terms of the concepts of affinity and efficacy of the ions at their receptor sites. PMID:4122664

Foreman, J. C.; Mongar, J. L.

1973-01-01

2

Separation of the Stern and diffuse layer in coarse-grained models: The cases of phosphatidyl serine, phosphatidic acid, and PIP2 monolayers  

NASA Astrophysics Data System (ADS)

We present here a method to separate the Stern and diffuse layer in general systems into two regions that can be analyzed separately. The Stern layer can be described in terms of Bjerrum pairing and the diffuse layer in terms of Poisson-Boltzmann theory (monovalent) or strong coupling theory plus a slowly decaying tail (divalent). We consider three anionic phospholipids: phosphatidyl serine, phosphatidic acid, and phosphatidylinositol(4,5)bisphosphate (PIP2), which we describe within a minimal coarse-grained model as a function of ionic concentration. The case of mixed lipid systems is also considered, which shows a high level of binding cooperativity as a function of PIP2 localization. Implications for existing experimental systems of lipid heterogeneities are also discussed.

Vangaveti, S.; Travesset, A.

2014-12-01

3

Use of molecular beacons to verify that the serine hydroxymethyltransferase pseudogene SHMT-ps1 is unique to the order Primates  

PubMed Central

Background: The serine hydroxymethyltransferase processed pseudogene SHMT-ps1 has been suggested to be unique to the order Primates because of the failure to amplify this sequence by PCR from genomic DNAs of any non-primate mammal species. Here, 'molecular beacon' probes specific to SHMT-ps1 were used in an attempt to verify this suggestion. Results: In a search for SHMT-ps1-specific sequences using molecular beacons across a range of mammalian species, SHMT-ps1 was only found in primates. The molecular beacon assays also showed that SHMT-ps1 is present in both Old World and New World species but not among prosimians. Conclusions: These results suggest that SHMT-ps1 originated close to the origin of the Anthropoidea, some 40 to 50 million years ago. PMID:11182889

Devor, Eric J

2001-01-01

4

PS MUSIC LAB PS PRACTICE  

E-print Network

) PS FACULTY (GP) PS LARGE RECORDING PS SMALL RECORDING SOUND LOCK PS CONTROL ROOM LACTATION ROOM SUPPORT PS INSTRUMENT STORAGE PS PRACTICE PS PRACTICE SOUND LOCK SOUND LOCK PS FACULTY (GP) PS FACULTY (UP COSTUME SHOP SOUND / LIGHT LOCK MEZZANINE ACCESS SOUND / LIGHT LOCK BLACK BOX THEATRE THAR SCENE SHOP

Bermúdez, José Luis

5

Isolation and Characterization of Phosphatidyl Choline from Spinach Leaves.  

ERIC Educational Resources Information Center

This inexpensive but informative experiment for undergraduate biochemistry students involves isolating phosphatidyl choline from spinach leaves. Emphasis is on introducing students to techniques of lipid extraction, separation of lipids, identification using thin layer chromatography, and identification of fatty acids. Three periods of three hours…

Devor, Kenneth A.

1979-01-01

6

Facile Synthesis of Phosphatidyl Saccharides for Preparation of Anionic Nanoliposomes with Enhanced Stability  

PubMed Central

Physical stability during storage and against processing such as dehyration/rehydration are the cornerstone in designing delivery vehicles. In this work, mono-, di- and tri-saccharides were enzymatically conjugated to phosphatidyl group through a facile approach namely phospholipase D (PLD) mediated transphosphatidylation in a biphasic reaction system. The purified products were structurally identified and the connectivities of carbohydrate to phosphatidyl moiety precisely mapped by 1H, 31P, 13C NMR pulse sequences and LC-ESI-FTMS. The synthetic phosphatidyl saccharides were employed as the sole biomimetic component for preparation of nanoliposomes. It was found that the critical micelle concentration (CMC) of phosphatidyl saccharides increases as more bulky sugar moiety (mono- to tri-) is introduced. Phosphatidyl di-saccharide had the largest membrane curvature. In comparison to the zwitterionic phosphatidylcholine liposome, all phosphatidyl saccharides liposomes are anionic and demonstrated significantly enhanced stability during storage. According to the confocal laser scan microscopy (CLSM) and atom force microscopy (AFM) analyses, the nanoliposomes formed by the synthetic phosphatidyl saccharides also show excellent stability against dehydration/rehydration process in which most of the liposomal structures remained intact. The abundance hydroxyl groups in the saccharide moieties might provide sufficient H-bondings for stabilization. This work demonstrated the synthesized phosphatidyl saccharides are capable of functioning as enzymatically liable materials which can form stable nanoliposomes without addition of stabilizing excipients. PMID:24069243

Song, Shuang; Cheong, Ling-Zhi; Falkeborg, Mia; Liu, Lei; Dong, Mingdong; Jensen, Henrik Max; Bertelsen, Kresten; Thorsen, Michael; Tan, Tianwei; Xu, Xuebing; Guo, Zheng

2013-01-01

7

Molecular Structure of Serine  

NSDL National Science Digital Library

Serine is required for the metabolism of fat, tissue growth, and a healthy immune system. It assists in the production of immunoglobulins and antibodies. Some of its derivatives such as ethanolamine are important components of the phospholipids found in biological membranes. Serine is found in meat and dairy products, wheat gluten, peanuts, and soy products. It is not clear how toxic this substance can be, although it is known that high levels of serine may cause immune suppression and psychological symptoms such as cerebral allergies.

2002-08-21

8

Serine utilization by Klebsiella aerogenes.  

PubMed Central

Klebsiella aerogenes was found to contain a specific L-serine dehydrase that was induced by threonine, glycine or leucine, but not by its substrate. Cellular concentrations were sensitive to carbon rather than nitrogen sources in the growth medium. A nonspecific isoleucine-sensitive L-threonine dehydrase supplemented the specific L-serine dehydrase activity. K. aerogenes also contains a leucine-inducible L-threonine dehydrogenase which probably initiated a threonine-utilization pathway in which the serine-specific dehydrate participated. Strains that were altered in their ability to metabolize serine differed in either L-serine dehydrase or L-threonine dehydrase activity. Thus, K. aerogenes growing on L-serine as a sole nitrogen source relies upon two enzymes that metabolize the amino acid as subsidiary functions. PMID:6783624

Vining, L C; Magasanik, B

1981-01-01

9

The phosphatidyl-myo-inositol mannosyltransferase PimA is essential for Mycobacterium tuberculosis growth in vitro and in vivo.  

PubMed

The cell envelope of Mycobacterium tuberculosis contains glycans and lipids of peculiar structure that play prominent roles in the biology and pathogenesis of tuberculosis. Consequently, the chemical structure and biosynthesis of the cell wall have been intensively investigated in order to identify novel drug targets. Here, we validate that the function of phosphatidyl-myo-inositol mannosyltransferase PimA is vital for M. tuberculosis in vitro and in vivo. PimA initiates the biosynthesis of phosphatidyl-myo-inositol mannosides by transferring a mannosyl residue from GDP-Man to phosphatidyl-myo-inositol on the cytoplasmic side of the plasma membrane. To prove the essential nature of pimA in M. tuberculosis, we constructed a pimA conditional mutant by using the TetR-Pip off system and showed that downregulation of PimA expression causes bactericidality in batch cultures. Consistent with the biochemical reaction catalyzed by PimA, this phenotype was associated with markedly reduced levels of phosphatidyl-myo-inositol dimannosides, essential structural components of the mycobacterial cell envelope. In addition, the requirement of PimA for viability was clearly demonstrated during macrophage infection and in two different mouse models of infection, where a dramatic decrease in viable counts was observed upon silencing of the gene. Notably, depletion of PimA resulted in complete clearance of the mouse lungs during both the acute and chronic phases of infection. Altogether, the experimental data highlight the importance of the phosphatidyl-myo-inositol mannoside biosynthetic pathway for M. tuberculosis and confirm that PimA is a novel target for future drug discovery programs. PMID:25049093

Boldrin, Francesca; Ventura, Marcello; Degiacomi, Giulia; Ravishankar, Sudha; Sala, Claudia; Svetlikova, Zuzana; Ambady, Anisha; Dhar, Neeraj; Kordulakova, Jana; Zhang, Ming; Serafini, Agnese; Vishwas, V G; Kolly, Gaëlle S; Kumar, Naveen; Palù, Giorgio; Guerin, Marcelo E; Mikusova, Katarina; Cole, Stewart T; Manganelli, Riccardo

2014-10-01

10

Fatty acids of bovine milk glycolipids and phospholipids and their specific distribution in the diacylglycerophospholipids  

Microsoft Academic Search

Milk lipids were fractionated by silicic acid column chromatography and preparative thinlayer chromatography (TLC). Ceramide\\u000a monohexoside (CMH), ceramide dihexoside (CDH), phosphatidyl ethanolamine (PE), phosphatidyl choline (PC), phosphatidyl serine\\u000a (PS), and sphingomyelin (Sph) were isolated, and the purity of each was checked by infrared spectroscopy and TLC. The diacylphospholipids\\u000a were hydrolyzed with phospholipase A and the products separated by TLC. Fatty

W. R. Morrison; E. L. Jack; L. M. Smith

1965-01-01

11

Mimosine targets serine hydroxymethyltransferase.  

PubMed

The plant amino acid, mimosine, is an extremely effective inhibitor of DNA replication in mammalian cells (Mosca, P. J., Dijkwel, P. A., and Hamlin, J. L. (1992) Mol. Cell. Biol. 12, 4375-4383). Mimosine appears to prevent the formation of replication forks at early-firing origins when delivered to mammalian cells approaching the G1/S boundary, and blocks DNA replication when added to S phase cells after a lag of approximately 2.5 h. We have shown previously that [3H]mimosine can be specifically photocross-linked both in vivo and in vitro to a 50-kDa polypeptide (p50) in Chinese hamster ovary (CHO) cells. In the present study, six tryptic peptides (58 residues total) from p50 were sequenced by tandem mass spectrometry and their sequences were found to be at least 77.5% identical and 96.5% similar to sequences in rabbit mitochondrial serine hydroxymethyltransferase (mSHMT). This assignment was verified by precipitating the [3H]mimosine-p50 complex with a polyclonal antibody to rabbit cSHMT. The 50-kDa cross-linked product was almost undetectable in a mimosine-resistant CHO cell line and in a CHO gly- cell line that lacks mitochondrial, but not cytosolic, SHMT activity. The gly- cell line is still sensitive to mimosine, suggesting that the drug may inhibit both the mitochondrial and the cytosolic forms. SHMT is involved in the penultimate step of thymidylate biosynthesis in mammalian cells and, as such, is a potential target for chemotherapy in the treatment of cancer. PMID:8576220

Lin, H B; Falchetto, R; Mosca, P J; Shabanowitz, J; Hunt, D F; Hamlin, J L

1996-02-01

12

21 CFR 582.5701 - Serine.  

Code of Federal Regulations, 2010 CFR

...GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5701 Serine. (a) Product. Serine (L- and DL-forms). (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good...

2010-04-01

13

p73 regulates serine biosynthesis in cancer.  

PubMed

Activation of serine biosynthesis supports growth and proliferation of cancer cells. Human cancers often exhibit overexpression of phosphoglycerate dehydrogenase (PHGDH), the metabolic enzyme that catalyses the reaction that diverts serine biosynthesis from the glycolytic pathway. By refueling serine biosynthetic pathways, cancer cells sustain their metabolic requirements, promoting macromolecule synthesis, anaplerotic flux and ATP. Serine biosynthesis intersects glutaminolysis and together with this pathway provides substrates for production of antioxidant GSH. In human lung adenocarcinomas we identified a correlation between serine biosynthetic pathway and p73 expression. Metabolic profiling of human cancer cell line revealed that TAp73 activates serine biosynthesis, resulting in increased intracellular levels of serine and glycine, associated to accumulation of glutamate, tricarboxylic acid (TCA) anaplerotic intermediates and GSH. However, at molecular level p73 does not directly regulate serine metabolic enzymes, but transcriptionally controls a key enzyme of glutaminolysis, glutaminase-2 (GLS-2). p73, through GLS-2, favors conversion of glutamine in glutamate, which in turn drives the serine biosynthetic pathway. Serine and glutamate can be then employed for GSH synthesis, thus the p73-dependent metabolic switch enables potential response against oxidative stress. In knockdown experiment, indeed, TAp73 depletion completely abrogates cancer cell proliferation capacity in serine/glycine-deprivation, supporting the role of p73 to help cancer cells under metabolic stress. These findings implicate p73 in regulation of cancer metabolism and suggest that TAp73 influences glutamine and serine metabolism, affecting GSH synthesis and determining cancer pathogenesis. PMID:24186203

Amelio, I; Markert, E K; Rufini, A; Antonov, A V; Sayan, B S; Tucci, P; Agostini, M; Mineo, T C; Levine, A J; Melino, G

2014-10-16

14

[Serine proteinase with lytic properties].  

PubMed

A thermophilic Bacillus licheniformis strain can synthesize extracellular serine proteinase, which is similar to subtilisin of the Carlsberg type in its amino acid composition, the specificity of its action, the character of its inhibition by certain compounds and immunochemical properties, but differs from the latter in its greater thermostability and in the ability to cause lysis of Gram-negative bacteria and yeast living cells. PMID:3141748

Pavlova, I N; Zholner, L G; Zakharova, I Ia; Tin'ianova, N Z; Chestukhina, G G

1988-01-01

15

The Structure of Mammalian Serine Racemase  

PubMed Central

Serine racemase is responsible for the synthesis of d-serine, an endogenous co-agonist for N-methyl-d-aspartate receptor-type glutamate receptors (NMDARs). This pyridoxal 5?-phosphate-dependent enzyme is involved both in the reversible conversion of l- to d-serine and serine catabolism by ?,?-elimination of water, thereby regulating d-serine levels. Because d-serine affects NMDAR signaling throughout the brain, serine racemase is a promising target for the treatment of disorders related to NMDAR dysfunction. To provide a molecular basis for rational drug design the x-ray crystal structures of human and rat serine racemase were determined at 1.5- and 2.1-Å resolution, respectively, and in the presence and absence of the orthosteric inhibitor malonate. The structures revealed a fold typical of ?-family pyridoxal 5?-phosphate enzymes, with both a large domain and a flexible small domain associated into a symmetric dimer, and indicated a ligand-induced rearrangement of the small domain that organizes the active site for specific turnover of the substrate. PMID:20106978

Smith, Myron A.; Mack, Volker; Ebneth, Andreas; Moraes, Isabel; Felicetti, Brunella; Wood, Michael; Schonfeld, Dorian; Mather, Owen; Cesura, Andrea; Barker, John

2010-01-01

16

Type II Transmembrane Serine Proteases*  

PubMed Central

Analysis of genome and expressed sequence tag data bases at the turn of the millennium unveiled a new protease family named the type II transmembrane serine proteases (TTSPs) in a Journal of Biological Chemistry minireview (Hooper, J. D., Clements, J. A., Quigley, J. P., and Antalis, T. M. (2001) J. Biol. Chem. 276, 857–860). Since then, the number of known TTSPs has more than doubled, and more importantly, our understanding of the physiological functions of individual TTSPs and their contribution to human disease has greatly increased. Progress has also been made in identifying molecular substrates and endogenous inhibitors. This minireview summarizes the current knowledge of the rapidly advancing TTSP field. PMID:19487698

Bugge, Thomas H.; Antalis, Toni M.; Wu, Qingyu

2009-01-01

17

Abnormal serine phosphorylation of insulin receptor substrate 1 is associated with tau pathology in Alzheimer's disease and tauopathies.  

PubMed

Neuronal insulin signaling abnormalities have been associated with Alzheimer's disease (AD). However, the specificity of this association and its underlying mechanisms have been unclear. This study investigated the expression of abnormal serine phosphorylation of insulin receptor substrate 1 (IRS1) in 157 human brain autopsy cases that included AD, tauopathies, ?-synucleinopathies, TDP-43 proteinopathies, and normal aging. IRS1-pS(616), IRS1-pS(312) and downstream target Akt-pS(473) measures were most elevated in AD but were also significantly increased in the tauopathies: Pick's disease, corticobasal degeneration and progressive supranuclear palsy. Double immunofluorescence labeling showed frequent co-expression of IRS1-pS(616) with pathologic tau in neurons and dystrophic neurites. To further investigate an association between tau and abnormal serine phosphorylation of IRS1, we examined the presence of abnormal IRS1-pS(616) expression in pathological tau-expressing transgenic mice and demonstrated that abnormal IRS1-pS(616) frequently co-localizes in tangle-bearing neurons. Conversely, we observed increased levels of hyperphosphorylated tau in the high-fat diet-fed mouse, a model of insulin resistance. These results provide confirmation and specificity that abnormal phosphorylation of IRS1 is a pathological feature of AD and other tauopathies, and provide support for an association between insulin resistance and abnormal tau as well as amyloid-?. PMID:25107476

Yarchoan, Mark; Toledo, Jon B; Lee, Edward B; Arvanitakis, Zoe; Kazi, Hala; Han, Li-Ying; Louneva, Natalia; Lee, Virginia M-Y; Kim, Sangwon F; Trojanowski, John Q; Arnold, Steven E

2014-11-01

18

Abnormal serine phosphorylation of insulin receptor substrate 1 is associated with tau pathology in Alzheimer's disease and tauopathies  

PubMed Central

Neuronal insulin signaling abnormalities have been associated with Alzheimer's disease (AD). However, the specificity of this association and its underlying mechanisms have been unclear. This study investigated the expression of abnormal serine phosphorylation of insulin receptor substrate 1 (IRS1) in 157 human brain autopsy cases that included AD, tauopathies, ?-synucleinopathies, TDP-43 proteinopathies, and normal aging. IRS1-pS616, IRS1-pS312 and downstream target Akt-pS473 measures were most elevated in AD but were also significantly increased in the tauopathies: Pick's disease, corticobasal degeneration and progressive supranuclear palsy. Double immunofluorescence labeling showed frequent co-expression of IRS1-pS616 with pathologic tau in neurons and dystrophic neurites. To further investigate an association between tau and abnormal serine phosphorylation of IRS1, we examined the presence of abnormal IRS1-pS616 expression in pathological tau-expressing transgenic mice and demonstrated that abnormal IRS1-pS616 frequently co-localizes in tangle-bearing neurons. Conversely, we observed increased levels of hyperphosphorylated tau in the high-fat diet-fed mouse, a model of insulin resistance. These results provide confirmation and specificity that abnormal phosphorylation of IRS1 is a pathological feature of AD and other tauopathies, and provide support for an association between insulin resistance and abnormal tau as well as amyloid-?. PMID:25107476

Yarchoan, Mark; Toledo, Jon B.; Lee, Edward B.; Arvanitakis, Zoe; Kazi, Hala; Han, Li-Ying; Louneva, Natalia; Lee, Virginia M.-Y.; Kim, Sangwon F.; Trojanowski, John Q.; Arnold, Steven E.

2015-01-01

19

Glycine and L-serine crystalline perhydrates.  

PubMed

We report the first crystalline amino acid perhydrates, show induced chirality of hydrogen peroxide in L-serine perhydrate, and demonstrate that the glycine perhydrate contains 40.47 wt% hydrogen peroxide. PMID:19585028

Churakov, Andrei V; Prikhodchenko, Petr V; Howard, Judith A K; Lev, Ovadia

2009-07-28

20

Restricted immunoglobulin variable region gene usage by normal Ly-1 (CD5+) B cells that recognize phosphatidyl choline  

PubMed Central

5-15% of lymphocytes in the peritoneums of normal adult B10.H-2aH- 4bp/Wts (2a4b) mice are CD5+ (Ly-1) B cells that recognize phosphatidyl choline (PtC), a phospholipid component of all mammalian cells. We produced a set of IgM-secreting hybridomas from the peritoneal cells of normal, adult 2a4b mice. We found that this set of hybridomas shows a similarly high frequency of antibodies specific for PtC (21 of 86) that also react with bromelain-treated mouse erythrocytes. Restriction fragment analysis of Ig gene rearrangements and analysis of expressed Ig idiotypes reveal that these cells use a restricted set of variable region genes to generate the PtC-specific antibodies. The Ig genes used by the PtC-specific hybridomas appear to be the same as those found in the PtC-specific Ly-1 B cell lymphomas, CH27 and CH34. PMID:2499651

1989-01-01

21

Interactions of the Auxilin-1 PTEN-like Domain with Model Membranes Result in Nanoclustering of Phosphatidyl Inositol Phosphates  

PubMed Central

Auxilin-1 is a neuron-specific membrane-binding protein involved in a late stage of clathrin-mediated endocytosis. It recruits Hsc70, thus initiating uncoating of the clathrin-coated vesicles. Interactions of auxilin-1 with the vesicle membrane are crucial for this function and are mediated via an N-terminal PTEN-like domain. We have used multiscale molecular dynamics simulations to probe the interactions of the auxilin-1 PTEN-like domain with lipid bilayers containing differing phospholipid composition, including bilayers containing phosphatidyl inositol phosphates. Our results suggest a novel, to our knowledge, model for the auxilin/membrane encounter and subsequent interactions. Negatively charged lipids (especially PIP2) enhance binding of auxilin to lipid bilayers and facilitate its correct orientation relative to the membrane. Mutations in three basic residues (R301E/R307E/K311E) of the C2 subdomain of the PTEN-like domain perturbed its interaction with the bilayer, changing its orientation. The interaction of membrane-bound auxilin-1 PTEN-like domain with negatively charged lipid headgroups results in nanoclustering of PIP2 molecules in the adjacent bilayer leaflet. PMID:23823232

Kalli, Antreas C.; Morgan, Gareth; Sansom, Mark S.P.

2013-01-01

22

Serine deprivation enhances antineoplastic activity of biguanides.  

PubMed

Metformin, a biguanide widely used in the treatment of type II diabetes, clearly exhibits antineoplastic activity in experimental models and has been reported to reduce cancer incidence in diabetics. There are ongoing clinical trials to evaluate its antitumor properties, which may relate to its fundamental activity as an inhibitor of oxidative phosphorylation. Here, we show that serine withdrawal increases the antineoplastic effects of phenformin (a potent biguanide structurally related to metformin). Serine synthesis was not inhibited by biguanides. Instead, metabolic studies indicated a requirement for serine to allow cells to compensate for biguanide-induced decrease in oxidative phosphorylation by upregulating glycolysis. Furthermore, serine deprivation modified the impact of metformin on the relative abundance of metabolites within the citric acid cycle. In mice, a serine-deficient diet reduced serine levels in tumors and significantly enhanced the tumor growth-inhibitory actions of biguanide treatment. Our results define a dietary manipulation that can enhance the efficacy of biguanides as antineoplastic agents that target cancer cell energy metabolism. Cancer Res; 74(24); 7521-33. ©2014 AACR. PMID:25377470

Gravel, Simon-Pierre; Hulea, Laura; Toban, Nader; Birman, Elena; Blouin, Marie-José; Zakikhani, Mahvash; Zhao, Yunhua; Topisirovic, Ivan; St-Pierre, Julie; Pollak, Michael

2014-12-15

23

D-serine increases adult hippocampal neurogenesis  

PubMed Central

Adult hippocampal neurogenesis results in the continuous formation of new neurons and is a process of brain plasticity involved in learning and memory. The neurogenic niche regulates the stem cell proliferation and the differentiation and survival of new neurons and a major contributor to the neurogenic niche are astrocytes. Among the molecules secreted by astrocytes, D-serine is an important gliotransmitter and is a co-agonist of the glutamate, N-methyl-D-aspartate (NMDA) receptor. D-serine has been shown to enhance the proliferation of neural stem cells in vitro, but its effect on adult neurogenesis in vivo is unknown. Here, we tested the effect of exogenous administration of D-serine on adult neurogenesis in the mouse dentate gyrus. We found that 1 week of treatment with D-serine increased cell proliferation in vivo and in vitro and increased the density of neural stem cells and transit amplifying progenitors. Furthermore, D-serine increased the survival of newborn neurons. Together, these results indicate that D-serine treatment resulted in the improvement of several steps of adult neurogenesis in vivo. PMID:24009551

Sultan, Sebastien; Gebara, Elias G.; Moullec, Kristell; Toni, Nicolas

2013-01-01

24

STAT3 phosphorylation at tyrosine 705 and serine 727 differentially regulates mouse ESC fates.  

PubMed

STAT3 can be transcriptionally activated by phosphorylation of its tyrosine 705 or serine 727 residue. In mouse embryonic stem cells (mESCs), leukemia inhibitory factor (LIF) signaling maintains pluripotency by inducing JAK-mediated phosphorylation of STAT3 Y705 (pY705). However, the function of phosphorylated S727 (pS727) in mESCs remains unclear. In this study, we examined the roles of STAT3 pY705 and pS727 in regulating mESC identities, using a small molecule-based system to post-translationally modulate the quantity of transgenic STAT3 in STAT3(-/-) mESCs. We demonstrated that pY705 is absolutely required for STAT3-mediated mESC self-renewal, while pS727 is dispensable, serving only to promote proliferation and optimal pluripotency. S727 phosphorylation is regulated directly by fibroblast growth factor/Erk signaling and crucial in the transition of mESCs from pluripotency to neuronal commitment. Loss of S727 phosphorylation resulted in significantly reduced neuronal differentiation potential, which could be recovered by a S727 phosphorylation mimic. Moreover, loss of pS727 sufficed LIF to reprogram epiblast stem cells to naïve pluripotency, suggesting a dynamic equilibrium of STAT3 pY705 and pS727 in the control of mESC fate. PMID:24302476

Huang, Guanyi; Yan, Hexin; Ye, Shoudong; Tong, Chang; Ying, Qi-Long

2014-05-01

25

Formation of a phospholipid-linked pyrrolecarbaldehyde from model reactions of D-glucose and 3-deoxyglucosone with phosphatidyl ethanolamine.  

PubMed

Phospholipid-linked 'advanced glycation end products' (AGEs) are supposed to play an important role for lipid oxidation in vivo. The identification of the pyrrolecarbaldehyde 1-[2-formyl-5-(hydroxymethyl)-1 H-pyrrol-1-yl]-4,10-dioxo-7-(tetradecanoyloxy)-3,5,9-trioxa- 4lambda5-phosphatricosan-4-olate (7) from model reactions of D-glucose or 3-deoxyglucosone (4, 3-DG) with phosphatidyl ethanolamine (PE) is described. A preparation method is given for 1-(2-hydrox¿ethyl)-5-(hydroxymethyl)-1H-pyrrole-2-carbaldehyde (8). Independent syntheses as well as unequivocal structural characterization are reported for the substitution products of 8 1-(2-hydroxyethyl)-5-(methoxymethyl)-1H-pyrrole-2-carbaldehyde (9a) and 5-(ethoxymethyl)-1-(2-hydroxyethyl)-1H-pyrrole-2-carbaldehyde (9b). For all these compounds, chromatographic and spectroscopic data were established by GLC-MS and HPLC with diode array detection (DAD). PE and D-glucose or 3-DG 4 were either incubated at pH 7.4, 100 degrees C for 3 h or at pH 7.4, 37 degrees C for 5 weeks in neat buffer or ethanol buffer mixtures. The phospholipid fraction was purified on a C18 solid-phase extraction column and cleaved with ethanolic potassium hydroxide. The carbaldehyde 8, released in this process, was identified bs GLC-MS and quantified by HPLC-DAD. Formation of 7 is favored in the ethanol buffer reactions relative to those in buffer solution only although the amounts determined from the 37 degrees C incubations generally are very low. It seems likely, therefore, that phospholipid-linked pyrrolecarbaldehydes, such as 7, are biomarkers rather than effectors of membrane damage in vivo. PMID:10968270

Lederer, M O; Baumann, M

2000-01-01

26

Viral Serine/Threonine Protein Kinases ?  

PubMed Central

Phosphorylation represents one the most abundant and important posttranslational modifications of proteins, including viral proteins. Virus-encoded serine/threonine protein kinases appear to be a feature that is unique to large DNA viruses. Although the importance of these kinases for virus replication in cell culture is variable, they invariably play important roles in virus virulence. The current review provides an overview of the different viral serine/threonine protein kinases of several large DNA viruses and discusses their function, importance, and potential as antiviral drug targets. PMID:21084474

Jacob, Thary; Van den Broeke, Céline; Favoreel, Herman W.

2011-01-01

27

Cross-talk between diverse serine integrases  

PubMed Central

Phage-encoded serine-integrases are large serine-recombinases that mediate integrative and excisive site-specific recombination of temperate phage genomes. They are well suited for use in heterologous systems and for synthetic genetic circuits as the attP and attB attachment sites are small (<50 bp), there are no host factor or DNA supercoiling requirements, and they are strongly directional, doing only excisive recombination in the presence of a recombination directionality factor. Combining different recombinases that function independently and without cross-talk to construct complex synthetic circuits is desirable, and several different serine-integrases are available. However, we show here that these functions are not reliably predictable, and we describe a pair of serine-integrases encoded by mycobacteriophages Bxz2 and Peaches with unusual and unpredictable specificities. The Integrases share only 59% amino acid sequence identity and the attP sites have fewer than 50% shared bases, but they use the same attB site and there is non-reciprocal cross-talk between the two systems. The DNA binding specificities do not result from differences in specific DNA contacts, but from the constraints imposed by the configuration of the component half-sites within each of the attachment site DNAs. PMID:24161951

Singh, Shweta; Rockenbach, Kate; Dedrick, Rebekah M.; VanDemark, Andrew

2013-01-01

28

Sorafenib/Regorafenib and Phosphatidyl Inositol 3 Kinase/Thymoma Viral Proto-Oncogene Inhibition Interact to Kill Tumor Cells  

PubMed Central

The present studies were undertaken to determine whether the multikinase inhibitors sorafenib/regorafenib cooperated with clinically relevant , phosphatidyl inositol 3 kinase (PI3K)-thymoma viral proto-oncogene (AKT) inhibitors to kill tumor cells. In liver, colorectal, lung, breast, kidney, and brain cancer cells, at clinically achievable doses, sorafenib/regorafenib and the PI3K inhibitor acetic acid (1S,4E,10R,11R,13S,14R)-[4-diallylaminomethylene-6-hydroxy-1-methoxymethyl-10,13-dimethyl-3,7,17-trioxo-1,3,4,7,10,11,12,13,14,15,16,17-dodecahydro-2-oxa-cyclopenta[a]phenanthren-11-yl ester (PX-866) cooperated in a greater than additive fashion to kill tumor cells. Cells lacking phosphatase and tensin homolog were as sensitive to the drug combination as cells expressing the protein. Similar data were obtained using the AKT inhibitors perifosine and 8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-1,2,4-triazolo[3,4-f] [1,6]naphthyridin-3(2H)-one hydrochloride (MK2206). PX-866 treatment abolished AKT/glycogen synthase kinase 3 (GSK3) phosphorylation, and cell killing correlated with reduced activity of AKT and mammalian target of rapamycin (mTOR). Expression of activated AKT and to a lesser extent activated mTOR reduced drug combination lethality. Expression of B-cell lymphoma–extra large or dominant negative caspase 9, but not cellular FLICE (FADD-like IL-1b–converting enzyme)-inhibitory protein short, protected cells from the drug combination. Treatment of cells with PX-866 increased protein levels of p62, lysosome-associated membrane protein 2 (LAMP2), and microtubule-associated protein light chain (LC) 3 and LC3II that correlated with a large increase in LC3–green fluorescent protein (GFP) vesicle numbers. Exposure of PX-866 treated cells to sorafenib reduced p62 and LAMP2 levels, decreased the ratio of LC3 to LC3II, and reduced LC3-GFP vesicle levels. Knockdown of Beclin1 or autophagy-related 5 suppressed drug toxicity by ?40%. In vivo, sorafenib and PX-866 or regorafenib and MK2206 cooperated to suppress the growth of established HuH7 and HCT116 tumors, respectively. Collectively our data demonstrate that the combination of sorafenib family kinase inhibitors with inhibitors of the PI3K/AKT pathway kills tumor cells in vitro and in vivo. PMID:23877009

Sajithlal, Gangadharan B.; Hamed, Hossein A.; Cruickshanks, Nichola; Booth, Laurence; Tavallai, Seyedmehrad; Syed, Jahangir; Grant, Steven; Poklepovic, Andrew

2013-01-01

29

In Vivo d-Serine Hetero-Exchange through Alanine-Serine-Cysteine (ASC) Transporters Detected by Microelectrode Biosensors  

PubMed Central

d-Serine, a co-agonist of N-methyl d-aspartate (NMDA) receptors, has been implicated in neurological and psychiatric disorders such as cerebral ischemia, lateral amyotrophic sclerosis, or schizophrenia. d-Serine signaling represents an important pharmacological target for treating these diseases; however, the biochemical mechanisms controlling extracellular d-serine levels in vivo are still unclear. d-Serine heteroexchange through small neutral amino acid transporters has been shown in cell cultures and brain slices and could provide a biochemical mechanism for the control of d-serine extracellular concentration in vivo. Alternatively, exocytotic d-serine release has also been proposed. In this study, the dynamics of d-serine release and clearance were explored in vivo on a second-by-second time scale using microelectrode biosensors. The rate of d-serine clearance in the rat frontal cortex after a microionophoretic injection revealed a transporter-mediated uptake mechanism. d-Serine uptake was blocked by small neutral l-amino acids, implicating alanine-serine-cysteine (ASC) transporters, in particular high affinity Asc-1 and low affinity ASCT2 transporters. Interestingly, changes in alanine, serine, or threonine levels resulted in d-serine release through ASC transporters. Asc-1, but not ASCT2, appeared to release d-serine in response to changes in amino acid concentrations. Finally, neuronal silencing by tetrodotoxin increased d-serine extracellular concentration by an ASC-transporter-dependent mechanism. Together, these results indicate that d-serine heteroexchange through ASC transporters is present in vivo and may constitute a key component in the regulation of d-serine extracellular concentration. PMID:23581544

2013-01-01

30

Apoptotic hepatocellular carcinoma HepG2 cells accelerate blood coagulation  

Microsoft Academic Search

Backgrounds and Aim: Intrasinusoidal microthrombosis is considered to be a cause of massive hepatocyte death in fulminant hepatic failure. Generally, apoptotic cells express phosphatidyl serine (PS) outside the plasma membrane, which is also expressed on the surface of activated platelets and accelerates fibrin–thrombus formation. Therefore, the acceleration of blood coagulation on the surface of apoptotic hepatocytes may occur because hepatocytes

Yasuhiro Miyamoto; Yasuhiro Takikawa; Shi De Lin; Shinichiro Sato; Kazuyuki Suzuki

2004-01-01

31

A bumblebee (Bombus ignitus) venom serine protease inhibitor that acts as a microbial serine protease inhibitor.  

PubMed

Serine protease inhibitors from bumblebee venom have been shown to block plasmin activity. In this study, we identified the protein BiVSPI from the venom of Bombus ignitus to be a serine protease inhibitor and an antimicrobial factor. BiVSPI is a 55-amino acid mature peptide with ten conserved cysteine residues and a P1 methionine residue. BiVSPI is expressed in the venom gland and also found in the venom as an 8-kDa peptide. Recombinant BiVSPI that was expressed in baculovirus-infected insect cells exhibited inhibitory activity against chymotrypsin but not trypsin. BiVSPI also inhibited microbial serine proteases, such as subtilisin A (Ki=6.57nM) and proteinase K (Ki=7.11nM). In addition, BiVSPI was shown to bind directly to Bacillus subtilis, Bacillus thuringiensis, and Beauveria bassiana but not to Escherichia coli. Consistent with these results, BiVSPI exhibited antimicrobial activity against Gram-positive bacteria and fungi. These findings provide evidence for a novel serine protease inhibitor in bumblebee venom that has antimicrobial functions. PMID:24158004

Wan, Hu; Kim, Bo Yeon; Lee, Kwang Sik; Yoon, Hyung Joo; Lee, Kyung Yong; Jin, Byung Rae

2014-01-01

32

ps  

E-print Network

Sep 17, 2014 ... negative coefficients, and every ? ? (0, ?/2), the number of roots in the. sector {z ? C? : |Arg ... (3) and u(z) = u(z) by potentials of the form log |P|/ deg P, where P is a .... simple direct computation shows that J?/?2 ? J, where.

2014-12-10

33

ps  

E-print Network

are the smallest and the largest roots of the equation P(x) ? ?n = 0. The. asymptotics .... and for applications to differential equations to [4, 5]. Let Q be an ...... [14] Y. Sibuya, Global theory of a second order linear ordinary differential. equation ...

34

ps  

E-print Network

Sep 7, 2014 ... equipped with a Riemannian metric of constant curvature 1, except ... equal to the integral curvature of the smooth part of the surface. It follows from ..... because the left-hand side of (5.1) is a polynomial of degree exactly p + q,.

2015-01-14

35

ps  

E-print Network

?n = ?n2 with irrational ?, the indicator is constant and f has com-. pletely regular growth ... and arguments of the form exp(2?i?n2), where ? is a quadratic irrationality. Such functions ..... We have the following integral representation: f(?z

36

ps  

E-print Network

plex plane C or the unit disc U. We say that the conformal type of X is elliptic,. parabolic or .... We have B(C,?) = B, where ? is the Weierstrass function of a hexagonal. lattice. .... However a geometric characterization of K-singularities is known.

37

ps  

E-print Network

Oct 15, 2011 ... Now we describe the necessary modifications of this proof for the case .... The inverse construction defines E up to a real affine transformation, and ..... [31] V. A. Malyshev, Abel's equation, (Russian) Algebra i Analiz 13 (2001),.

2011-10-15

38

Metabolic Engineering of Corynebacterium glutamicum for l-Serine Production  

PubMed Central

Although l-serine proceeds in just three steps from the glycolytic intermediate 3-phosphoglycerate, and as much as 8% of the carbon assimilated from glucose is directed via l-serine formation, previous attempts to obtain a strain producing l-serine from glucose have not been successful. We functionally identified the genes serC and serB from Corynebacterium glutamicum, coding for phosphoserine aminotransferase and phosphoserine phosphatase, respectively. The overexpression of these genes, together with the third biosynthetic serA gene, serA?197, encoding an l-serine-insensitive 3-phosphoglycerate dehydrogenase, yielded only traces of l-serine, as did the overexpression of these genes in a strain with the l-serine dehydratase gene sdaA deleted. However, reduced expression of the serine hydroxymethyltransferase gene glyA, in combination with the overexpression of serA?197, serC, and serB, resulted in a transient accumulation of up to 16 mM l-serine in the culture medium. When sdaA was also deleted, the resulting strain, C. glutamicum ?sdaA::pK18mobglyA?(pEC-T18mob2serA?197CB), accumulated up to 86 mM l-serine with a maximal specific productivity of 1.2 mmol h?1?g (dry weight)?1. This illustrates a high rate of l-serine formation and also utilization in the C. glutamicum wild type. Therefore, metabolic engineering of l-serine production from glucose can be achieved only by addressing the apparent key position of this amino acid in the central metabolism. PMID:16269752

Peters-Wendisch, Petra; Stolz, Michael; Etterich, Helga; Kennerknecht, Nicole; Sahm, Hermann; Eggeling, Lothar

2005-01-01

39

ORAL SUPPLEMENTATION AND COGNITIVE FUNCTION IN THE ELDERLY: REVIEW ARTICLE \\  

Microsoft Academic Search

OBJECTIVE: We review the experimental evaluations of several widely marketed nonprescription com- pounds claimed to be memory enhancers and treatments for age-related memory decline. We generally limit our review to double-blind placebo-controlled studies. The compounds examined are phosphatidyl- serine (PS), phosphatidylcholine (PC), citicoline, piracetam, vinpocetine, acetyl-L-carnitine (ALC), and antioxidants (particularly vitamin E). RESULTS: In animals, PS has been shown to

Mark A. McDaniel; Steven F. Maier; Gilles O. Einstein

40

The expanding diversity of serine hydrolases Istvan Botos1  

E-print Network

. They are classified into six classes on the basis of their catalytic mechanism: serine, threonine, cysteine, aspartate or cysteine share the fold with serine proteases; they will not be further dis- cussed here). Typical SPs have was revealed by its crystal structure [2]. Human tissue kallikreins (hK) belong to a closely related 15-member

41

Fibrin(ogen)olytic activity of bumblebee venom serine protease  

Microsoft Academic Search

Bee venom is a rich source of pharmacologically active components; it has been used as an immunotherapy to treat bee venom hypersensitivity, and venom therapy has been applied as an alternative medicine. Here, we present evidence that the serine protease found in bumblebee venom exhibits fibrin(ogen)olytic activity. Compared to honeybee venom, bumblebee venom contains a higher content of serine protease,

Yuling Qiu; Young Moo Choo; Hyung Joo Yoon; Jingming Jia; Zheng Cui; Dong Wang; Doh Hoon Kim; Hung Dae Sohn; Byung Rae Jin

2011-01-01

42

D-Serine Regulation of NMDA Receptor Activity  

NSDL National Science Digital Library

The N-Methyl-D-aspartate–type glutamate receptor (NMDAR) plays a key role in several important processes involving the nervous system, including brain development, synaptic plasticity, and learning. Unlike other neurotransmitter receptors, which are activated by individual neurotransmitters, activation of NMDARs requires the binding of a coagonist (D-serine or glycine) in addition to glutamate. Although previously considered an "unnatural" amino acid, D-serine is a key regulator of NMDAR activity and may be the main physiological ligand at the coagonist site. D-Serine is synthesized in the mammalian brain and is enriched in astrocytes, a class of glial cells that ensheath synapses in the brain. Astrocytes physiologically affect NMDAR neurotransmission by releasing D-serine, suggesting that D-serine acts as a gliotransmitter. However, recent findings indicate that D-serine signaling does not depend solely on glia, because D-serine and its biosynthetic enzyme are also present in substantial amounts in neurons. Here, we discuss these new findings, which begin to shed light on the relative roles of glia and neurons in D-serine signaling.

Herman Wolosker (Technion-Israel Institute of Technology;Department of Biochemistry REV)

2006-10-10

43

l-Serine Uptake by Human Placental Microvillous Membrane Vesicles  

Microsoft Academic Search

The human fetus requires more glycine than any other amino acid but placental glycine transfer to the fetus is insufficient to meet fetal demand. l-Serine could represent a major metabolic source of glycine for the human fetus but little is known about the kinetics and physiology of l-serine uptake by the human placenta. We have characterised the amino acid transport

R. M. Lewis; J. Glazier; S. L. Greenwood; E. J. Bennett; K. M. Godfrey; A. A. Jackson; C. P. Sibley; I. T. Cameron; M. A. Hanson

2007-01-01

44

Production of L-serine by Sarcina albida.  

PubMed Central

Conditions for the production of microbial L-serine hydroxymethyltransferase and for the conversion of glycine to L-serine were studied. A number of microorganisms were screened for their abilities to form and accululate L-serine from glycine, and Sarcina albida was selected as the best organism. Enzyme activity in this organism as high as 0.12 U/ml could be produced in shaken cultures at 30 degrees C in a medium containing glucose, ammonium sulfate, glycine, yeast extract, and inorganic salts. L-Serine was produced most efficiently by shaking cells at 30 degrees C in a reaction mixture containing 20% glycine, 5 X 10(-3) M formaldehyde, and 3 X 10(-4) M pyridoxal phosphate in yields of 22 mg of broth in 5 days. L-Serine was easily isolated in 84% yields by ion-exchange resin. PMID:39497

Ema, M; Kakimoto, T; Chibata, I

1979-01-01

45

Complement factor D, a novel serine protease.  

PubMed Central

Factor D is unique among serine proteases in that it requires neither enzymatic cleavage for expression of proteolytic activity nor inactivation by a serpin for its control. Regulation of factor D activity is instead attained by a novel mechanism that depends on reversible conformational changes for expression and control of catalytic activity. These conformational changes are believed to be induced by the single natural substrate, C3bB, and to result in realignment of the catalytic triad, the specificity pocket, and the nonspecific substrate binding site, all of which have atypical conformations. Mutational studies have defined structural determinants responsible for these unique structural features of factor D and for the resultant low reactivity with synthetic esters. PMID:8845746

Volanakis, J. E.; Narayana, S. V.

1996-01-01

46

Ps-atom scattering at low energies  

E-print Network

A pseudopotential for positronium-atom interaction, based on electron-atom and positron-atom phase shifts, is constructed, and the phase shifts for Ps-Kr and Ps-Ar scattering are calculated. This approach allows us to extend the Ps-atom cross sections, obtained previously in the impulse approximation [Phys. Rev. Lett. 112, 243201 (2014)], to energies below the Ps ionization threshold. Although experimental data are not available in this low-energy region, our results describe well the tendency of the measured cross sections to drop with decreasing velocity at $venergy region, in contrast to the inter...

Fabrikant, I I

2015-01-01

47

Fibrin(ogen)olytic activity of bumblebee venom serine protease  

SciTech Connect

Bee venom is a rich source of pharmacologically active components; it has been used as an immunotherapy to treat bee venom hypersensitivity, and venom therapy has been applied as an alternative medicine. Here, we present evidence that the serine protease found in bumblebee venom exhibits fibrin(ogen)olytic activity. Compared to honeybee venom, bumblebee venom contains a higher content of serine protease, which is one of its major components. Venom serine proteases from bumblebees did not cross-react with antibodies against the honeybee venom serine protease. We provide functional evidence indicating that bumblebee (Bombus terrestris) venom serine protease (Bt-VSP) acts as a fibrin(ogen)olytic enzyme. Bt-VSP activates prothrombin and directly degrades fibrinogen into fibrin degradation products. However, Bt-VSP is not a plasminogen activator, and its fibrinolytic activity is less than that of plasmin. Taken together, our results define roles for Bt-VSP as a prothrombin activator, a thrombin-like protease, and a plasmin-like protease. These findings offer significant insight into the allergic reaction sequence that is initiated by bee venom serine protease and its potential usefulness as a clinical agent in the field of hemostasis and thrombosis. - Graphical abstract: Display Omitted Highlights: > Bumblebee venom serine protease (Bt-VSP) is a fibrin(ogen)olytic enzyme. > Bt-VSP activates prothrombin. > Bt-VSP directly degrades fibrinogen into fibrin degradation products. > Bt-VSP is a hemostatically active protein that is a potent clinical agent.

Qiu Yuling [College of Natural Resources and Life Science, Dong-A University, Busan 604-714 (Korea, Republic of); Joint Laboratory between Dong-A University and Shenyang Pharmaceutical University, Shenyang Pharmaceutical University, Shenyang (China); Choo, Young Moo [College of Natural Resources and Life Science, Dong-A University, Busan 604-714 (Korea, Republic of); Yoon, Hyung Joo [Department of Agricultural Biology, National Academy of Agricultural Science, Suwon (Korea, Republic of); Jia Jingming; Cui Zheng; Wang Dong [Joint Laboratory between Dong-A University and Shenyang Pharmaceutical University, Shenyang Pharmaceutical University, Shenyang (China); Kim, Doh Hoon [College of Natural Resources and Life Science, Dong-A University, Busan 604-714 (Korea, Republic of); Joint Laboratory between Dong-A University and Shenyang Pharmaceutical University, Shenyang Pharmaceutical University, Shenyang (China); Sohn, Hung Dae [College of Natural Resources and Life Science, Dong-A University, Busan 604-714 (Korea, Republic of); Jin, Byung Rae, E-mail: brjin@dau.ac.kr [College of Natural Resources and Life Science, Dong-A University, Busan 604-714 (Korea, Republic of); Joint Laboratory between Dong-A University and Shenyang Pharmaceutical University, Shenyang Pharmaceutical University, Shenyang (China)

2011-09-01

48

Positron and positronium chemistry by quantum Monte Carlo. III. Ground state of [OH,Ps], [CH,Ps], and [NH2,Ps] complexes  

Microsoft Academic Search

The stability of the [OH,Ps], [CH,Ps] and [NH2,Ps] complexes, where Ps = (e+,e-), have been studied using Monte Carlo techniques and explicitly correlated trial wave functions. For these systems we have computed the ground state energy values using both variational Monte Carlo and fixed node diffusion Monte Carlo methods. Diffusion Monte Carlo results allow us to predict [OH,Ps] and [CH,Ps

Dario Bressanini; Massimo Mella; Gabriele Morosi

1998-01-01

49

Approach to knowledge of the interaction between the constituents of contact lenses and ocular tears: mixed monolayers of poly(methyl methacrylate) and dipalmitoyl phosphatidyl choline.  

PubMed

Mixed monolayers of poly(methyl methacrylate) (PMMA), the main component of hard contact lenses, and dipalmitoyl phosphatidyl choline (DPPC), a characteristic phospholipidic constituent of ocular tear films, were selected as an in vitro model in order to observe the behavior of contact lenses on the eye. Using Langmuir monolayer and Brewster angle microscopy (BAM) techniques, the interaction between both components was analyzed from the data of surface pressure-area isotherms, compressional modulus-surface pressure, and relative film thickness versus time elapsed from the beginning of compression, together with BAM images. Regardless of the surface pressure at which the molecular/monomer areas (A(m)) were recorded, the A(m) mole fractions of PMMA (X(PMMA)) plots show that the experimental results match the theoretical values calculated from additivity rule A(m) = X(PMMA)A(PMMA) + X(DPPC)A(DPPC). The application of the Crisp phase rule to the phase diagram of the PMMA-DPPC system can explain the existence of a mixed monolayer made up of miscible components with ideal behavior at surface pressures below 25 mN/m. However, at very high surface pressures, when collapse is reached (at 60 mN/m), the single collapsed components are segregated into two independent phases. These results allows us to argue that PMMA hard contact lenses in the eye do not alter the structural characteristics of the phospholipid (DPPC) in tears. PMID:21370907

Miñones Conde, M; Conde, O; Trillo, J M; Miñones, J

2011-04-01

50

Structure-Based Design of an Organoruthenium Phosphatidyl-inositol-3-Kinase Inhibitor Reveals a Switch Governing Lipid Kinase Potency and Selectivity  

SciTech Connect

Mutations that constitutively activate the phosphatidyl-inositol-3-kinase (PI3K) signaling pathway, including alterations in PI3K, PTEN, and AKT, are found in a variety of human cancers, implicating the PI3K lipid kinase as an attractive target for the development of therapeutic agents to treat cancer and other related diseases. In this study, we report on the combination of a novel organometallic kinase inhibitor scaffold with structure-based design to develop a PI3K inhibitor, called E5E2, with an IC50 potency in the mid-low-nanomolar range and selectivity against a panel of protein kinases. We also show that E5E2 inhibits phospho-AKT in human melanoma cells and leads to growth inhibition. Consistent with a role for the PI3K pathway in tumor cell invasion, E5E2 treatment also inhibits the migration of melanoma cells in a 3D spheroid assay. The structure of the PI3K?/E5E2 complex reveals the molecular features that give rise to this potency and selectivity toward lipid kinases with implications for the design of a subsequent generation of PI3K-isoform-specific organometallic inhibitors.

Xie,P.; Williams, D.; Atilla-Gokcumen, G.; Milk, L.; Xiao, M.; Smalley, K.; Herlyn, M.; Meggers, E.; Marmorstein, R.

2008-01-01

51

The PS 40 MHz bunching cavity  

Microsoft Academic Search

A 40 MHz cavity has been designed and built at CERN as part of the preparation of the PS as injector for LHC. The cavity will provide the necessary bunch spacing of 25 ns prior to injection into SPS and subsequently LHC. The mechanical design of the copper coated steel cavity was dominated by space constraints in the PS tunnel

R. Garoby; D G Grier; E. Jensen; A. Mitra; R. L. Poirier

1997-01-01

52

THE PS 40 MHZ BUNCHING CAVITY  

Microsoft Academic Search

A 40 MHz cavity has been designed and built at CERN as part of the preparation of the PS as injector for LHC. The cavity will provide the necessary bunch spacing of 25 ns prior to injection into SPS and subsequently LHC. The mechanical design of the copper coated steel cavity was dominated by space constraints in the PS tunnel

R. Garoby; D. Grier; E. Jensen; A. Mitra; R. L. Poirier

1998-01-01

53

Console Hacking 2010 PS3 Epic Fail  

E-print Network

Console Hacking 2010 PS3 Epic Fail bushing, marcan, segher, sven 27th Chaos Communication Congress Hack Homebrew Channel Drivechips Bannerbomb Bannerbomb for 4.2 latest update broken Indiana Pwns t Wii Xbox 360 PS3 2006 2011 2010 2009 2008 2007 Mittwoch, 29. Dezember 2010 #12;Twiizer Attack Twilight Hack

Touretzky, David S.

54

Mycobacterium tuberculosis Serine/Threonine Protein Kinases.  

PubMed

The Mycobacterium tuberculosis genome encodes 11 serine/threonine protein kinases (STPKs). A similar number of two-component systems are also present, indicating that these two signal transduction mechanisms are both important in the adaptation of this bacterial pathogen to its environment. The M. tuberculosis phosphoproteome includes hundreds of Ser- and Thr-phosphorylated proteins that participate in all aspects of M. tuberculosis biology, supporting a critical role for the STPKs in regulating M. tuberculosis physiology. Nine of the STPKs are receptor type kinases, with an extracytoplasmic sensor domain and an intracellular kinase domain, indicating that these kinases transduce external signals. Two other STPKs are cytoplasmic and have regulatory domains that sense changes within the cell. Structural analysis of some of the STPKs has led to advances in our understanding of the mechanisms by which these STPKs are activated and regulated. Functional analysis has provided insights into the effects of phosphorylation on the activity of several proteins, but for most phosphoproteins the role of phosphorylation in regulating function is unknown. Major future challenges include characterizing the functional effects of phosphorylation for this large number of phosphoproteins, identifying the cognate STPKs for these phosphoproteins, and determining the signals that the STPKs sense. Ultimately, combining these STPK-regulated processes into larger, integrated regulatory networks will provide deeper insight into M. tuberculosis adaptive mechanisms that contribute to tuberculosis pathogenesis. Finally, the STPKs offer attractive targets for inhibitor development that may lead to new therapies for drug-susceptible and drug-resistant tuberculosis. PMID:25429354

Prisic, Sladjana; Husson, Robert N

2014-10-01

55

Serine kinases of insulin receptor substrate proteins.  

PubMed

Signaling of insulin and insulin-like growth factor-I (IGF-1) at target tissues is essential for growth, development and for normal homeostasis of glucose, fat, and protein metabolism. Control over this process is therefore tightly regulated. It can be achieved by a negative-feedback control mechanism, whereby downstream components inhibit upstream elements along the insulin and IGF-1 signaling pathway or by signals from other pathways that inhibit insulin/IGF-1 signaling thus leading to insulin/IGF-1 resistance. Phosphorylation of insulin receptor substrates (IRS) proteins on serine residues has emerged as a key step in these control processes both under physiological and pathological conditions. The list of IRS kinases is growing rapidly, concomitant with the list of potential Ser/Thr phosphorylation sites in IRS proteins. Here we review a range of conditions that activate IRS kinases to phosphorylate IRS proteins on selected domains. The specificity of this reaction is discussed and its characteristic as an "array" phosphorylation is suggested. Finally, its implications on insulin/IGF-1 signaling, insulin/IGF-1 resistance and diabetes, an emerging epidemic of the twenty-first century are outlined. PMID:19251043

Boura-Halfon, Sigalit; Zick, Yehiel

2009-01-01

56

The subcellular distribution of rat liver serine-pyruvate aminotransferase.  

PubMed Central

1. The subcellular distribution of L-serine-pyruvate aminotransferase activity in rat liver was investigated. About 80% was recovered from cell-free homogenates in a 'total-particles' fraction and the remainder in the cytosol. 2. Subfractionation of the particles by differential sedimentation and on sucrose density gradients showed a distribution for serine-pyruvate aminotransferase activity closely matching that observed for mitochondrial marker enzymes. 3. A study of the solubilization of enzymes from combined subcellular particles by digitonin at various concentrations also indicated a common subcellular location for serine-pyruvate aminotransferase and established mitochondrial enzymes. 4. The increase in liver serine-pyruvate amino-transferase activity induced by glucagon injection was accounted for as an increased mitochondrial activity. PMID:7092827

Rowsell, K V; Al-Naama, L M; Benett, P

1982-01-01

57

ACTIVATION OF A CRYPTIC D-SERINE DEAMINASE (DSD) GENE FROM PSEUDOMONAS CEPACIA 17616  

EPA Science Inventory

D-serine inhibits growth of P. cepacia 17616; however, resistant mutants able to express an ordinarily cryptic D-serine deaminase (dsd) gene were isolated readily. The resistant strains formed high levels of a D-serine deaminase active on D-threonine as well as D-serine. IS eleme...

58

Characterization of aL-serine dehydratase activity from Streptococcus faecalis  

E-print Network

Characterization of aL-serine dehydratase activity from Streptococcus faecalis Le Lait, 191111 Streptococcus faecalis sp. produces pyruvate and ammonia from L-serine via a specifie L-serine dehydratase. The enzymatic activity is stimulated by Fe2 + ions. Key words: Streptococcus faecalis - L-serine dehydratase

Paris-Sud XI, Université de

59

Sequence and phylogenetic analysis of viper venom serine proteases  

PubMed Central

Snakebites are a major neglected tropical disease responsible for as many as 95000 deaths every year worldwide. Viper venom serine proteases disrupt haemostasis of prey and victims by affecting various stages of the blood coagulation system. A better understanding of their sequence, structure, function and phylogenetic relationships will improve the knowledge on the pathological conditions and aid in the development of novel therapeutics for treating snakebites. A large dataset for all available viper venom serine proteases was developed and analysed to study various features of these enzymes. Despite the large number of venom serine protease sequences available, only a small proportion of these have been functionally characterised. Although, they share some of the common features such as a C-terminal extension, GWG motif and disulphide linkages, they vary widely between each other in features such as isoelectric points, potential N-glycosylation sites and functional characteristics. Some of the serine proteases contain substitutions for one or more of the critical residues in catalytic triad or primary specificity pockets. Phylogenetic analysis clustered all the sequences in three major groups. The sequences with substitutions in catalytic triad or specificity pocket clustered together in separate groups. Our study provides the most complete information on viper venom serine proteases to date and improves the current knowledge on the sequence, structure, function and phylogenetic relationships of these enzymes. This collective analysis of venom serine proteases will help in understanding the complexity of envenomation and potential therapeutic avenues. PMID:23055627

Vaiyapuri, Sakthivel; Thiyagarajan, Nethaji; Hutchinson, E Gail; Gibbins, Jonathan M

2012-01-01

60

The PS1 Gigapixel Camera  

NASA Astrophysics Data System (ADS)

The world's largest and most advanced digital camera has been installed on the Pan-STARRS-1 (PS1) telescope on Haleakala, Maui. Built at the University of Hawaii at Manoa's Institute for Astronomy (IfA) in Honolulu, the gigapixel camera will capture images that will be used to scan the skies for killer asteroids, and to create the most comprehensive catalog of stars and galaxies ever produced. The CCD sensors at the heart of the camera were developed in collaboration with Lincoln Laboratory of the Massachusetts Institute of Technology. The image area, which is about 40 cm across, contains 60 identical silicon chips, each of which contains 64 independent imaging circuits. Each of these imaging circuits contains approximately 600 x 600 pixels, for a total of about 1.4 gigapixels in the focal plane. The CCDs themselves employ the innovative technology called "orthogonal transfer." Splitting the image area into about 4,000 separate regions in this way has three advantages: data can be recorded more quickly, saturation of the image by a very bright star is confined to a small region, and any defects in the chips only affect only a small part of the image area. The CCD camera is controlled by an ultrafast 480-channel control system developed at the IfA. The individual CCD cells are grouped in 8 x 8 arrays on a single silicon chip called an orthogonal transfer array (OTA), which measures about 5 cm square. There are a total of 60 OTAs in the focal plane of each telescope.

Tonry, John L.; Isani, S.; Onaka, P.

2007-12-01

61

Cross genome comparisons of serine proteases in Arabidopsis and rice  

PubMed Central

Background Serine proteases are one of the largest groups of proteolytic enzymes found across all kingdoms of life and are associated with several essential physiological pathways. The availability of Arabidopsis thaliana and rice (Oryza sativa) genome sequences has permitted the identification and comparison of the repertoire of serine protease-like proteins in the two plant species. Results Despite the differences in genome sizes between Arabidopsis and rice, we identified a very similar number of serine protease-like proteins in the two plant species (206 and 222, respectively). Nearly 40% of the above sequences were identified as potential orthologues. Atypical members could be identified in the plant genomes for Deg, Clp, Lon, rhomboid proteases and species-specific members were observed for the highly populated subtilisin and serine carboxypeptidase families suggesting multiple lateral gene transfers. DegP proteases, prolyl oligopeptidases, Clp proteases and rhomboids share a significantly higher percentage orthology between the two genomes indicating substantial evolutionary divergence was set prior to speciation. Single domain architectures and paralogues for several putative subtilisins, serine carboxypeptidases and rhomboids suggest they may have been recruited for additional roles in secondary metabolism with spatial and temporal regulation. The analysis reveals some domain architectures unique to either or both of the plant species and some inactive proteases, like in rhomboids and Clp proteases, which could be involved in chaperone function. Conclusion The systematic analysis of the serine protease-like proteins in the two plant species has provided some insight into the possible functional associations of previously uncharacterised serine protease-like proteins. Further investigation of these aspects may prove beneficial in our understanding of similar processes in commercially significant crop plant species. PMID:16895613

Tripathi, Lokesh P; Sowdhamini, R

2006-01-01

62

Determination of the PS I content of PS II core preparations using selective emission: a new emission of PS II at 780nm.  

PubMed

Routinely prepared PS II core samples are often contaminated by a significant (~1-5%) fraction of PS I, as well as related proteins. This contamination is of little importance in many experiments, but masks the optical behaviour of the deep red state in PS II, which absorbs in the same spectral range (700-730nm) as PS I (Hughes et al. 2006). When contamination levels are less than ~1%, it becomes difficult to quantify the PS I related components by gel-based, chromatographic, circular dichroism or EPR techniques. We have developed a fluorescence-based technique, taking advantage of the distinctively different low-temperature emission characteristics of PS II and PS I when excited near 700nm. The approach has the advantage of providing the relative concentration of the two photosystems in a single spectral measurement. A sensitivity limit of 0.01% PS I (or better) can be achieved. The procedure is applied to PS II core preparations from spinach and Thermosynechococcus vulcanus. Measurements made of T. vulcanus PS II preparations prepared by re-dissolving crystallised material indicate a low but measurable PS I related content. The analysis provides strong evidence for a previously unreported fluorescence of PS II cores peaking near 780nm. The excitation dependence of this emission as well as its appearance in both low PS I cyanobacterial and plant based PS II core preparations suggests its association with the deep red state of PS II. PMID:24055633

Morton, Jennifer; Hall, Jeremy; Smith, Paul; Akita, Fusamichi; Koua, Faisal Hammad Mekky; Shen, Jian-Ren; Krausz, Elmars

2014-01-01

63

Drosophila PS1 integrin is a laminin receptor and differs in ligand specificity from PS2.  

PubMed Central

We have expressed Drosophila position-specific (PS) integrins on the surfaces of Schneider S2 cells and tested for adhesion and spreading on various matrix molecules. We report that PS1 integrin is a laminin receptor and that PS1 and PS2 integrins promote cell spreading on two different Drosophila extracellular matrix molecules, laminin and tiggrin, respectively. The differing ligand specificities of these two integrins, combined with data on the in vivo expression patterns of the integrins and their ligands, lead to a model for the structure of integrin-dependent attachments in the pupal wings and embryonic muscles of Drosophila. Images PMID:7972082

Gotwals, P J; Fessler, L I; Wehrli, M; Hynes, R O

1994-01-01

64

A proposed mechanism for IS607-family serine transposases  

PubMed Central

Background The transposases encoded by the IS607 family of mobile elements are unusual serine recombinases with an inverted domain order and minimal specificity for target DNA. Results Structural genomics groups have determined three crystal structures of the catalytic domains of IS607 family transposases. The dimers formed by these catalytic domains are very different from those seen for other serine recombinases and include interactions that usually only occur upon formation of a synaptic tetramer. Conclusions Based on these structures, we propose a model for how IS607-family transposases could form a synaptic tetramer. The model suggests that, unlike other serine recombinases, these enzymes carry out sequence-specific DNA binding and catalysis in trans: the DNA binding and catalytic domains of each subunit are proposed to interact with different DNA duplexes. The model also suggests an explanation for the minimal target DNA specificity. PMID:24195768

2013-01-01

65

Accelerated evolution of crotalinae snake venom gland serine proteases.  

PubMed

Eight cDNAs encoding serine proteases isolated from Trimeresurus flavoviridis (habu snake) and T. gramineus (green habu snake) venom gland cDNA libraries showed that nonsynonymous nucleotide substitutions have accumulated in the mature protein-coding regions to cause amino acid changes. Southern blot analysis of T. flavoviridis genomic DNAs using two proper probes indicated that venom gland serine protease genes form a multigene family in the genome. These observations suggest that venom gland serine proteases have diversified their amino acid sequences in an accelerating manner. Since a similar feature has been previously discovered in crotalinae snake venom gland phospholipase A2 (PLA2) isozyme genes, accelerated evolution appears to be universal in plural isozyme families of crotalinae snake venom gland. PMID:8941719

Deshimaru, M; Ogawa, T; Nakashima, K; Nobuhisa, I; Chijiwa, T; Shimohigashi, Y; Fukumaki, Y; Niwa, M; Yamashina, I; Hattori, S; Ohno, M

1996-11-11

66

Phosphoramidates as novel activity-based probes for serine proteases.  

PubMed

Activity-based probes (ABPs) are small molecules that exclusively form covalent bonds with catalytically active enzymes. In the last decade, they have especially been used in functional proteomics studies of proteases. Here, we present phosphoramidate peptides as a novel type of ABP for serine proteases. These molecules can be made in a straightforward manner by standard Fmoc-based solid-phase peptide synthesis, allowing rapid diversification. The resulting ABPs covalently bind different serine proteases, depending on the amino acid recognition element adjacent to the reactive group. A reporter tag enables downstream gel-based analysis or LC-MS/MS-mediated identification of the targeted proteases. Overall, we believe that these readily accessible probes will provide new avenues for the functional study of serine proteases in complex proteomes. PMID:24817682

Haedke, Ute R; Frommel, Sandra C; Hansen, Fabian; Hahne, Hannes; Kuster, Bernhard; Bogyo, Matthew; Verhelst, Steven H L

2014-05-26

67

Enhanced expression of serine proteases during floral senescence in Gladiolus.  

PubMed

Programmed cell death during senescence in plants is associated with proteolysis that helps in remobilization of nitrogen to other growing tissues. In this paper, we provide one of the few reports for the expression of specific serine proteases during senescence associated proteolysis in Gladiolus grandiflorus flowers. Senescence in tepals, stamens and carpels results in an increase in total protease activity and a decrease in total protein content. Of the total protease activity, serine proteases account for about 67-70% while cysteine proteases account for only 23-25%. In-gel assays using gelatin as a substrate and specific protease inhibitors reveal the enhanced activity of two trypsin-type serine proteases of sizes 75 kDa and 125 kDa during the course of senescence. The activity of the 125 kDa protease increases not only during tepal senescence but also during stamen and carpel senescence indicating that it is responsive to general senescence signals. PMID:17412375

Azeez, Abdul; Sane, Aniruddha P; Bhatnagar, D; Nath, Pravendra

2007-05-01

68

CRTS observations of recent PS1 transients  

NASA Astrophysics Data System (ADS)

Valenti et al. (2010, ATel#2773) recently reported the discovery of an AGN outburst (PS1-1000382) detected in PS1 taken data on June 12.23 UT with magnitude g=17.9. The redshift of the AGN is given by Valenti et al. (2010) as z=0.435 and host galaxy SDSS J160414.08+091354.0. We have extracted the five year archival CSS/CRTS lightcurve at the location of PS1-1000382 and SDSS DR7 data.

Drake, A. J.; Mahabal, A. A.; Djorgovski, S. G.; Graham, M. J.; Williams, R.; Prieto, J.; Catelan, M.; Christensen, E.; Beshore, E. C.; Larson, S. M.

2010-08-01

69

Expression and characterization of Coprothermobacter proteolyticus alkaline serine protease  

Technology Transfer Automated Retrieval System (TEKTRAN)

TECHNICAL ABSTRACT A putative protease gene (aprE) from the thermophilic bacterium Coprothermobacter proteolyticus was cloned and expressed in Bacillus subtilis. The enzyme was determined to be a serine protease based on inhibition by PMSF. Biochemical characterization demonstrated the enzyme had...

70

Dynamics simulation of the interaction between serine and water  

NASA Astrophysics Data System (ADS)

Using the first principles density functional theory (DFT), we simulated the neutron scattering spectra of the hydration dynamics of serine. Experimental data analyses have shown that dissociative H2O molecules were more likely to form hydrogen bonds (H-bonds) with an -OH group in monohydrated serine and easily shift to a -NH_3 ^ + group at a higher hydration level [P. Zhang, Y. Zhang, S. H. Han, Q. W. Yan, R. C. Ford, and J. C. Li, J. Phys. Chem. A 110, 5000 (2006), 10.1021/jp0569741]. We set the 1:1 ratio hydrated compounds at the two positions and found that the H2O could be optimized to form H-bonds with -OH and -NH3+ separately. When the simulated phonon signals of the -OH…H2O and -NH3+…H2O combinations were summed on a 3:1 scale, the calculating spectra were in good agreement with the experimental results, especially for the peak at 423 cm-1 of the -OH…H2O combination and the peak at 367 cm-1 of the -NH3+…H2O combination, which mutually complemented the real spectrum. We confirm that H2O may break the intermolecular H-bonds of the interlaced binding -OH to form a new structure, and that with the skeleton deformation of serine, H2O forms stronger H-bonds more often with the -NH3+ side indicating the flexible dynamic mechanism of the serine hydration process.

Liu, Yang; Zhang, Peng; Lu, Ying-Bo; Han, Sheng-Hao; Yu, Hui

2013-05-01

71

A serine sensor for multicellularity in a bacterium  

PubMed Central

We report the discovery of a simple environmental sensing mechanism for biofilm formation in the bacterium Bacillus subtilis that operates without the involvement of a dedicated RNA or protein. Certain serine codons, the four TCN codons, in the gene for the biofilm repressor SinR caused a lowering of SinR levels under biofilm-inducing conditions. Synonymous substitutions of these TCN codons with AGC or AGT impaired biofilm formation and gene expression. Conversely, switching AGC or AGT to TCN codons upregulated biofilm formation. Genome-wide ribosome profiling showed that ribosome density was higher at UCN codons than at AGC or AGU during biofilm formation. Serine starvation recapitulated the effect of biofilm-inducing conditions on ribosome occupancy and SinR production. As serine is one of the first amino acids to be exhausted at the end of exponential phase growth, reduced translation speed at serine codons may be exploited by other microbes in adapting to stationary phase. DOI: http://dx.doi.org/10.7554/eLife.01501.001 PMID:24347549

Subramaniam, Arvind R; DeLoughery, Aaron; Bradshaw, Niels; Chen, Yun; O’Shea, Erin; Losick, Richard; Chai, Yunrong

2013-01-01

72

Localization of Serine Racemase and Its Role in the Skin  

PubMed Central

D-Serine is an endogenous coagonist of the N-methyl-D-aspartate (NMDA)–type glutamate receptor in the central nervous system and its synthesis is catalyzed by serine racemase (SR). Recently, the NMDA receptor has been found to be expressed in keratinocytes (KCs) of the skin and involved in the regulation of KC growth and differentiation. However, the localization and role of SR in the skin remain unknown. Here, using SR-knockout (SR-KO) mice as the control, we demonstrated the localization of the SR protein in the granular and cornified layer of the epidermis of wild-type (WT) mice and its appearance in confluent WT KCs. We also demonstrated the existence of a mechanism for conversion of L-serine to D-serine in epidermal KCs. Furthermore, we found increased expression levels of genes involved in the differentiation of epidermal KCs in adult SR-KO mice, and alterations in the barrier function and ultrastructure of the epidermis in postnatal day 5 SR-KO mice. Our findings suggest that SR in the skin epidermis is involved in the differentiation of epidermal KCs and the formation of the skin barrier. PMID:24441099

Inoue, Ran; Yoshihisa, Yoko; Tojo, Yosuke; Okamura, Chieko; Yoshida, Yuzo; Kishimoto, Jiro; Luan, Xinghua; Watanabe, Masahiko; Mizuguchi, Mineyuki; Nabeshima, Yuko; Hamase, Kenji; Matsunaga, Kenji; Shimizu, Tadamichi; Mori, Hisashi

2014-01-01

73

Purification and Characterization of Serine Racemase from a Hyperthermophilic Archaeon, Pyrobaculum islandicum  

Microsoft Academic Search

Pyrobaculum islandicum is an anaerobic hyperthermophilic archaeon that is most active at 100°C. A pyridoxal 5-phosphate-dependent serine racemase called Srr was purified from the organism. The corresponding srr gene was cloned, and recombinant Srr was purified from Escherichia coli. It showed the highest racemase activity toward L-serine, followed by L-threonine, D-serine, and D-threonine. Like rodent and plant serine racemases, Srr

Masato Ohnishi; Makoto Saito; Sadao Wakabayashi; Morio Ishizuka; Katsushi Nishimura; Yoko Nagata; Sabu Kasai

2008-01-01

74

Two-dimensional thin-layer chromatography of rat liver phosphatides  

Microsoft Academic Search

SUMMARY A system of two-dimensional thin-layer chromatography was developed that separated rat liver phosphatides into several phosphate-positive spots in about 2 hr developing time. Characteristic hydrolysis products derived from phosphatidyl serine, phosphatidyl ethanolamine, phosphatidyl inositol, phosphatidyl choline, sphingomyelin, and lysophos- phatidyl choline were identified. The hydrolytic products of \\

W. D. SKIDMORE; C. ENTENMAN

75

Identification and structural analysis of four serine proteases in a monotreme, the platypus, Ornithorhynchus anatinus  

Microsoft Academic Search

To study the emergence of the major subfamilies of serine proteases during vertebrate evolution, we present here the primary structure of four serine proteases expressed in the spleen of a monotreme, the platypus, Ornithorhynchus anatinus. Partial cDNA clones for four serine proteases were isolated by a PCR-based strategy. This strategy is based on the high level of sequence identity between

Maryam Poorafshar; Maria Aveskogh; Barry Munday; Lars Hellman

2000-01-01

76

Inhibition of lung serine proteases in mice: a potentially new approach to control influenza infection  

Microsoft Academic Search

BACKGROUND: Host serine proteases are essential for the influenza virus life cycle because the viral haemagglutinin is synthesized as a precursor which requires proteolytic maturation. Therefore, we studied the activity and expression of serine proteases in lungs from mice infected with influenza and evaluated the effect of serine protease inhibitors on virus replication both in cell culture and in infected

Mahmoud M Bahgat; Paulina B?azejewska; Klaus Schughart

2011-01-01

77

P.S. to PS (Phosphatidylserine) Pertinent Proteins in Apoptotic Cell Clearance  

NSDL National Science Digital Library

The psr protein has been proposed as the critical receptor that detects phosphatidylserine (PS) on the surface of apoptotic cells. However, for some time there has been evidence that this protein is not at the cell surface but in the nucleus. Now, the phenotype of a knockout of the Drosophila psr protein (dPSR) has discredited the identification altogether, lending impetus both to uncovering the real function of the protein and to identifying the real PS receptor. Interpretations of studies of two other genes supposedly involved in PS transport may be built on similarly shaky foundations.

Robert A. Schlegel (Pennsylvania State University;Department of Biochemistry and Molecular Biology REV); Patrick Williamson (Amherst College;Department of Biology REV)

2007-10-16

78

usersmeeting.ps.bnl.gov Plenary Session  

E-print Network

Plenary Speakers Howard Schneider and Elizabeth Bass, Center for Communicating Science, Stony Brook to Synchrotron Radiation Wednesday, May 22 Charge Transfer on the Nanoscale Center for Communicating ScienceSHARING OUR SCIENCE TELLING OUR STORY... usersmeeting.ps.bnl.gov Plenary Session Tuesday, May 21

Homes, Christopher C.

79

The 4 Ps as a Guiding Perspective  

ERIC Educational Resources Information Center

A 4 Ps perspective addresses immediate needs: to help institutions gain traction in their retention strategies by framing and reframing the challenges and the possible responses, by challenging some of the traditional mental models about retention that can distract or dilute those strategies, and by offering focus and coherence to institutional…

Kalsbeek, David H.

2013-01-01

80

Beyond metric gravity: Progress on PS-200  

SciTech Connect

The reconciliation of quantum mechanics and gravity on varying distance scales requires changes to General Relativity that may be testable implications. We briefly review the status of tests with matter of the inverse square law and the principle of equivalence, then report on progress on the drift-tube measurement section of PS- 200, the experiment to measure the gravitational acceleration of antiprotons.

Goldman, T.; Brown, R.E.; Camp, J.B.; Darling, T.; Dyer, P.; Holzscheiter, M.H.; Hughes, R.J.; Jarmie, N.; King, N.S.P.; Lizon, D.C.; Nieto, M.M.; Schauer, M.M.M.; Schecker, J.A. (Los Alamos National Lab., NM (United States)); Cornford, S.; Hosea, K.; Kenefick, R.A. (Texas A and M Univ., College Station, TX (United States)); Hoibraaten, S.; Midzor, M.M.; Parry, S.P.; Ristenen, R.A. (Colorado Univ., Boulder, CO (U

1993-01-01

81

Beyond metric gravity: Progress on PS-200  

SciTech Connect

The reconciliation of quantum mechanics and gravity on varying distance scales requires changes to General Relativity that may be testable implications. We briefly review the status of tests with matter of the inverse square law and the principle of equivalence, then report on progress on the drift-tube measurement section of PS- 200, the experiment to measure the gravitational acceleration of antiprotons.

Goldman, T.; Brown, R.E.; Camp, J.B.; Darling, T.; Dyer, P.; Holzscheiter, M.H.; Hughes, R.J.; Jarmie, N.; King, N.S.P.; Lizon, D.C.; Nieto, M.M.; Schauer, M.M.M.; Schecker, J.A. [Los Alamos National Lab., NM (United States); Cornford, S.; Hosea, K.; Kenefick, R.A. [Texas A and M Univ., College Station, TX (United States); Hoibraaten, S.; Midzor, M.M.; Parry, S.P.; Ristenen, R.A. [Colorado Univ., Boulder, CO (United States); Witteborn, F.C. [National Aeronautics and Space Administration, Moffett Field, CA (United States). Ames Research Center; Rochet, J. [European Organization for Nuclear Research, Geneva (Switzerland)

1993-03-01

82

p27Kip1 serine 10 phosphorylation determines its metabolism and interaction with cyclin-dependent kinases.  

PubMed

p27Kip1 is a critical modulator of cell proliferation by controlling assembly, localization and activity of cyclin-dependent kinase (CDK). p27Kip1 also plays important roles in malignant transformation, modulating cell movement and interaction with the extracellular matrix. A critical p27Kip1 feature is the lack of a stable tertiary structure that enhances its "adaptability" to different interactors and explains the heterogeneity of its function. The absence of a well-defined folding underlines the importance of p27Kip1 post-translational modifications that might highly impact the protein functions. Here, we characterize the metabolism and CDK interaction of phosphoserine10-p27Kip1 (pS10- p27Kip1), the major phosphoisoform of p27Kip1. By an experimental strategy based on specific immunoprecipitation and bidimensional electrophoresis, we established that pS10-p27Kip1 is mainly bound to cyclin E/CDK2 rather than to cyclin A/CDK2. pS10- p27Kip1 is more stable than non-modified p27Kip1, since it is not (or scarcely) phosphorylated on T187, the post-translational modification required for p27Kip1 removal in the nucleus. pS10-p27Kip1 does not bind CDK1. The lack of this interaction might represent a mechanism for facilitating CDK1 activation and allowing mitosis completion. In conclusion, we suggest that nuclear p27Kip1 follows 2 almost independent pathways operating at different rates. One pathway involves threonine-187 and tyrosine phosphorylations and drives the protein toward its Skp2-dependent removal. The other involves serine-10 phosphorylation and results in the elongation of p27Kip1 half-life and specific CDK interactions. Thus, pS10-p27Kip1, due to its stability, might be thought as a major responsible for the p27Kip1-dependent arrest of cells in G1/G0 phase. PMID:25483085

Bencivenga, Debora; Tramontano, Annunziata; Borgia, Alessia; Negri, Aide; Caldarelli, Ilaria; Oliva, Adriana; Perrotta, Silverio; Della Ragione, Fulvio; Borriello, Adriana

2014-01-01

83

AVO approximation for PS-wave and its application in PP/PS joint inversion  

NASA Astrophysics Data System (ADS)

Multi-component exploration has many advantages over ordinary P-wave exploration. PP/PS joint AVO analysis and inversion are useful and powerful methods to discriminate between reservoir and non-productive lithology. In this paper, we derive a new PS-wave reflection coefficient approximation equation which is more accurate at larger incidence angles. The equation is simplified for small incidence angles, which makes AVO analysis clearer and easier for angles less than 30 degrees. Based on this approximation, a PP/PS joint inversion is introduced. A real data example shows that oil sands, brine sands and shales can be differentiated based on the P- to S-wave velocity ratio from the PP/PS joint inversion. Fluid factors and Poisson's ratio also indicate an anomaly in the target zone at the oil well location.

Wang, Pu; Hu, Tian-Yue

2011-09-01

84

Plasma Motion during the Formation Phase of the PS3 and PS3.5 Spheromaks  

Microsoft Academic Search

Spectroscopic Doppler shift measurements of a CIII impurity ion in the ultraviolet are reported from the University of Maryland spheromak experiments PS-3 and PS-3.5. A new time and space resolved Doppler shift diagnostic with absolute wavelength calibration to +\\/- 0.02 A is described. The spheromak is a member of the compact toroid class of magnetic confinement devices. Spheromak formation is

Thomas Arnold Peyser

1987-01-01

85

The Nef protein of human immunodeficiency virus type 1 enhances serine phosphorylation of the viral matrix.  

PubMed Central

The human immunodeficiency virus type 1 matrix (MA) protein is phosphorylated during virion maturation on its C-terminal tyrosine and on several serine residues. Whereas MA tyrosine phosphorylation facilitates viral nuclear import, the significance of MA serine phosphorylation remains unclear. Here, we report that MA serine but not tyrosine phosphorylation is strongly enhanced by Nef. Mutations that abrogated the membrane association of Nef and its ability to bind a cellular serine/threonine kinase greatly diminished the extent of virion MA serine phosphorylation. Correspondingly, a protein kinase coimmunoprecipitated with Nef could phosphorylate MA on serine in vitro, producing a phosphopeptide pattern reminiscent of that of virion MA. Recombinant p21-activated kinase hPAK65, a recently proposed relative of the Nef-associated kinase, achieved a comparable result. Taken together, these data suggest that MA is a target of the Nef-associated serine kinase. PMID:9151826

Swingler, S; Gallay, P; Camaur, D; Song, J; Abo, A; Trono, D

1997-01-01

86

Chlorophyllase as a serine hydrolase: identification of a putative catalytic triad.  

PubMed

Chlorophyllases (Chlases), cloned so far, contain a lipase motif with the active serine residue of the catalytic triad of triglyceride lipases. Inhibitors specific for the catalytic serine residue in serine hydrolases, which include lipases effectively inhibited the activity of the recombinant Chenopodium album Chlase (CaCLH). From this evidence we assumed that the catalytic mechanism of hydrolysis by Chlase might be similar to those of serine hydrolases that have a catalytic triad composed of serine, histidine and aspartic acid in their active site. Thus, we introduced mutations into the putative catalytic residue (Ser162) and conserved amino acid residues (histidine, aspartic acid and cysteine) to generate recombinant CaCLH mutants. The three amino acid residues (Ser162, Asp191 and His262) essential for Chlase activity were identified. These results indicate that Chlase is a serine hydrolase and, by analogy with a plausible catalytic mechanism of serine hydrolases, we proposed a mechanism for hydrolysis catalyzed by Chlase. PMID:12552153

Tsuchiya, Tohru; Suzuki, Takuo; Yamada, Takafumi; Shimada, Hiroshi; Masuda, Tatsuru; Ohta, Hiroyuki; Takamiya, Ken-ichiro

2003-01-01

87

Membrane-anchored serine proteases in health and disease  

PubMed Central

Serine proteases of the trypsin-like family have long been recognized to be critical effectors of biological processes as diverse as digestion, blood coagulation, fibrinolysis, and immunity. In recent years, a subgroup of these enzymes has been identified that are anchored directly to plasma membranes, either by a carboxy-terminal transmembrane domain (Type I), an amino-terminal transmembrane domain with a cytoplasmic extension (Type II or TTSP), or through a glycosyl-phosphatidylinositol (GPI) linkage. Recent biochemical, cellular, and in vivo analyses have now established that membrane-anchored serine proteases are key pericellular contributors to processes vital for development and the maintenance of homeostasis. This chapter will review our current knowledge of the biological and physiological functions of these proteases, their molecular substrates, and their contributions to disease. PMID:21238933

Bugge, Thomas; Wu, Qingyu

2013-01-01

88

ZnO/PS/p-Si heterojunction properties  

NASA Astrophysics Data System (ADS)

In this paper porous silicon (PS) has been prepared by electrochemical etching technique and then ZnO thin film deposition on PS by spray pyrolysis method, the study of AFM show improve the structural stability of the PS substrate with crystalline growth of ZnO thin film. PL spectra explained a blue-shifting in PS layer come from oxidation the surface of PS after coating with ZnO film, Raman measurement show quantum confinement in PS layers with decreasing in variation mode of ZnO film, and the J-V characteristic show increasing in resistivity of Al/ZnO/PS/c-Si/Al due to increasing in depletion layer junction compere with PS layer.

Muhsin Nayef, Uday; Waleed Muayad, Mohammed; Amer Khalaf, Haider

2014-05-01

89

Serine\\/Threonine Protein Phosphatase Inhibitors with Antitumor Activity  

Microsoft Academic Search

Recent studies with fostriecin and derivatives of cantharidin suggest that the development of specific, or highly selective,\\u000a inhibitors of serine\\/threonine protein phosphatases, notably PP2A, PP4, and PP5, may prove useful for the medical management\\u000a of human cancer. This chapter will review the discovery and development of natural compounds that were originally shown to\\u000a have marked antitumor activity and subsequently found

R. E. Honkanen

90

Serine racemase: a key player in apoptosis and necrosis  

PubMed Central

A fine balance between cell survival and cell death is required to sculpt the nervous system during development. However, an excess of cell death can occur following trauma, exposure to neurotoxins or alcohol, and some developmental and neurodegenerative diseases, such as Alzheimer's disease (AD). N-Methyl-D-aspartate receptors (NMDARs) support synaptic plasticity and survival of many neuronal populations whereas inappropriate activation may promote various forms of cell death, apoptosis, and necrosis representing the two extremes of a continuum of cell death processes both “in vitro” and “in vivo.” Hence, by identifying the switches controlling pro-survival vs. apoptosis and apoptosis vs. pro-excitotoxic outcome of NMDAR stimulation, NMDAR modulators could be developed that selectively block the cell death enhancing pro-survival signaling or synaptic plasticity mediated by NMDAR. Among these modulators, a role is emerging for the enzyme serine racemase (SR) that synthesizes D-serine, a key co-agonist with glutamate at NMDAR. This review summarizes the experimental evidence from “in vitro” neuronal cultures—with special emphasis on cerebellar granule neurons (CGNs)—and “in vivo” models of neurodegeneration, where the dual role of the SR/D-serine pathway as a master regulator of apoptosis and the apoptosis-necrosis shift will be discussed. PMID:24795622

Canu, Nadia; Ciotti, Maria Teresa; Pollegioni, Loredano

2014-01-01

91

Structural Basis for Catalytic Activation of a Serine Recombinase  

SciTech Connect

Sin resolvase is a site-specific serine recombinase that is normally controlled by a complex regulatory mechanism. A single mutation, Q115R, allows the enzyme to bypass the entire regulatory apparatus, such that no accessory proteins or DNA sites are required. Here, we present a 1.86 {angstrom} crystal structure of the Sin Q115R catalytic domain, in a tetrameric arrangement stabilized by an interaction between Arg115 residues on neighboring subunits. The subunits have undergone significant conformational changes from the inactive dimeric state previously reported. The structure provides a new high-resolution view of a serine recombinase active site that is apparently fully assembled, suggesting roles for the conserved active site residues. The structure also suggests how the dimer-tetramer transition is coupled to assembly of the active site. The tetramer is captured in a different rotational substate than that seen in previous hyperactive serine recombinase structures, and unbroken crossover site DNA can be readily modeled into its active sites.

Keenholtz, Ross A.; Rowland, Sally-J.; Boocock, Martin R.; Stark, W. Marshall; Rice, Phoebe A. (Glasgow); (UC)

2014-10-02

92

College of Arts and Sciences PS Political Science  

E-print Network

College of Arts and Sciences PS Political Science KEY: # = new course * = course changed = course TO POLITICAL ANALYSIS. (3) Introduction to the basic knowledge of research methodology in political science. Prereq: UN2 status; PS majors only. PS 391 SPECIAL TOPICS IN POLITICAL SCIENCE (Subtitle required). (3

MacAdam, Keith

93

The HARP detector at the CERN PS  

Microsoft Academic Search

HARP is a high-statistics, large solid angle experiment to measure hadron production using proton and pion beams with momenta between 1.5 and 15GeV\\/c impinging on many different solid and liquid targets from low to high Z. The experiment, located in the T9 beam of the CERN PS, took data in 2001 and 2002. For the measurement of momenta of produced

M. G. Catanesi; M. T. Muciaccia; E. Radicioni; S. Simone; R. Edgecock; M. Ellis; S. Robbins; F. J. P. Soler; C. Gößling; M. Mass; S. Bunyatov; A. Chukanov; O. Klimov; I. Krasin; A. Krasnoperov; D. Kustov; B. Popov; V. Serdiouk; V. Tereshchenko; V. Carassiti; E. Di Capua; F. Evangelisti; G. Vidal-Sitjes; A. Artamonov; P. Arce; R. Brocard; G. Decreuse; B. Friend; S. Giani; S. Gilardoni; P. Gorbunov; A. Grant; A. Grossheim; P. Gruber; V. Ivanchenko; J.-C. Legrand; A. Kayis-Topaksu; J. Panman; I. Papadopoulos; J. Pasternak; E. Tcherniaev; I. Tsukerman; R. van der Vlugt; R. Veenhof; C. Wiebusch; P. Zucchelli; A. Blondel; S. Borghi; M. Campanelli; A. Cervera-Villanueva; M. C. Morone; G. Prior; R. Schroeter; I. Kato; U. Gastaldi; G. B. Mills; J. S. Graulich; G. Grégoire; M. Bonesini; F. Chignoli; F. Ferri; F. Paleari; M. Kirsanov; V. Postoev; A. Bagulya; V. Grichine; N. Polukhina; V. Palladino; L. Coney; D. Schmitz; G. Barr; A. De Santo; C. Pattison; K. Zuber; G. Barichello; F. Bobisut; D. Gibin; A. Guglielmi; M. Laveder; A. Menegolli; M. Mezzetto; A. Pepato; J. Dumarchez; S. Troquereau; F. Vannucci; U. Dore; A. Iaciofano; M. Lobello; F. Marinilli; D. Orestano; D. Panayotov; M. Pasquali; F. Pastore; A. Tonazzo; L. Tortora; C. Booth; C. Buttar; P. Hodgson; L. Howlett; R. Nicholson; M. Bogomilov; K. Burin; M. Chizhov; D. Kolev; P. Petev; I. Rusinov; R. Tsenov; S. Piperov; P. Temnikov; M. Apollonio; P. Chimenti; G. Giannini; G. Santin; J. Burguet-Castell; J. J. Gómez-Cadenas; P. Novella; M. Sorel; A. Tornero

2007-01-01

94

Intrinsic Viscosity Characterization of PS and PMMA  

NSDL National Science Digital Library

In this experiment, you will use intrinsic viscosity measurements to determine the molecular weight of polystyrene, PS, or poly(methyl methacrylate), PMMA. After in-class presentation, completion of hands-on laboratory experiment and review of the information provided, you should be able to: ⢠Identify several laboratory methods for molecular weight analysis of polymers. ⢠Confidently discuss the differences between the methods of analysis for polymer molecular weight. ⢠Discuss how polymer solution behavior affects molecular weight measurements.

Derosa, Rebecca L.

2008-09-26

95

Rubidium penta­aqua­(l-serine)cobalt(II) hexa­hydrogenhexa­molybdocobaltate(III) l-serine monosolvate deca­hydrate  

PubMed Central

The Co2+ ion in the title compound, Rb[Co(C3H7NO3)(H2O)5][H6CoMo6O24]·C3H7NO3·10H2O, is coordinated by five water mol­ecules and one O-monodentate l-serine ligand in a slightly distorted octahedral geometry. The Rb+ ion is irregularly coordinated by nine O atoms. In the crystal, the [H6CoIIIMo6O24]3? polyanions are stacked along the b-axis direction, mediated by bridging Rb—O bonds. N—H?O and O—H?O hydrogen bonds are observed involving the l-serine mol­ecules. PMID:24454041

Iijima, Jun; Naruke, Haruo; Takiyama, Hiroshi

2013-01-01

96

The PS 40 MHz bunching cavity  

E-print Network

A 40 MHz cavity has been designed and built at CERN as part of the preparation of the PS as injector for LHC. The cavity will provide the necessary bunch spacing of 25 ns prior to injection into SPS and subsequently LHC. The mechanical design of the copper coated steel cavity was dominated by space constraints in the PS tunnel and by vacuum requirements. The salient design features described are i) tight, multipactor-free, capacitive coupling from the power amplifier, ii) fast RF feedback, iii) inductively coupled tuners, iv) an efficient, pneumatically operated gap short-circuit. The operation cycle consists of an adiabatic capture up to 100 kV gap voltage, a non-adiabatic jump to 300 kV, and subsequent bunch rotation. The multipactor voltage level at the gap lies below the operating voltage range and is easily passed through. A fast RF feedback system with a total group delay of 220 ns copes with heavy beam loading (1011 protons/bunch) and prevents unwanted interaction with other beams in the PS. The cavity...

Garoby, R; Jensen, E; Mitra, A; Poirier, R L

1998-01-01

97

The PS 40 MHz Bunching Cavity  

NASA Astrophysics Data System (ADS)

A 40 MHz cavity has been designed and built at CERN as part of the preparation of the PS as injector for LHC. The cavity will provide the necessary bunch spacing of 25 ns prior to injection into SPS and subsequently LHC. The mechanical design of the copper coated steel cavity was dominated by space constraints in the PS tunnel and by vacuum requirements. Salient design features are described, like i) tight, multipactor-free, capacitive coupling from the power amplifier, ii) fast RF feedback, iii) inductively coupled tuners, iv) an efficient, pneumatically operated gap short-circuit. The operation cycle consists of an adiabatic capture up to 100 kV gap voltage, a non-adiabatic jump to 300 kV, and subsequent bunch rotation. The multipactor voltage level at the gap lies below the operation voltage range and is easily passed through. A fast RF feedback system with a total group delay of 220 ns copes with heavy beam loading (10^11 protons/bunch), and prevents unwanted interaction with other beams in the PS. The cavity has recently been installed; the nominal gap voltage of 300 kV has been attained, and bunch lengths below 8 ns have been achieved in first tests at nominal intensity. Experimental results are reported.

Jensen, E.; Garoby, R.; Grier, E.; Mitra, A.; Poirier, R. L.

1997-05-01

98

Phosphorylation of Raf1 Serine 338Serine 339 Is an Essential Regulatory Event for Ras-Dependent Activation and Biological Signaling  

Microsoft Academic Search

Activation of the Raf serine\\/threonine protein kinases is tightly regulated by multiple phosphorylation events. Phosphorylation of either tyrosine 340 or 341 in the catalytic domain of Raf-1 has been previously shown to induce the ability of the protein kinase to phosphorylate MEK. By using a combination of mitogenic and enzymatic assays, we found that phosphorylation of the adjacent residue, serine

BRUCE DIAZ; DARLENE BARNARD; ADELE FILSON; SUSAN MACDONALD; ALASTAIR KING; MARK MARSHALL

1997-01-01

99

L-Serine Catabolism via an Oxygen-Labile L-Serine Dehydratase Is Essential for Colonization of the Avian Gut by Campylobacter jejuni  

Microsoft Academic Search

Campylobacter jejuni is a microaerophilic, asaccharolytic bacterium. The identity of the carbon and energy sources used by C. jejuni in vivo is unknown, but the genome sequence of strain NCTC11168 indicates the presence of genes for catabolism of a limited range of amino acids, including serine. Specific omission of L-serine from a defined medium containing a mixture of amino acids

Jyoti Velayudhan; Michael A. Jones; Paul A. Barrow; David J. Kelly

2004-01-01

100

Protein kinase C spatially and temporally regulates gap junctional communication during human wound repair via phosphorylation of connexin43 on serine368  

PubMed Central

Phosphorylation of connexin43 (Cx43) on serine368 (S368) has been shown to decrease gap junctional communication via a reduction in unitary channel conductance. Examination of phosphoserine368 (pS368) in normal human skin tissue using a phosphorylation site–specific antibody showed relatively even distribution throughout the epidermal layers. However, 24 h after wounding, but not at 6 or 72 h, pS368 levels were dramatically increased in basal keratinocytes and essentially lost from suprabasal layers adjacent to the wound (i.e., within 200 ?m of it). Scratch wounding of primary human keratinocytes caused a protein kinase C (PKC)-dependent increase in pS368 in cells adjacent to the scratch, with a time course similar to that found in the wounds. Keratinocytes at the edge of the scratch also transferred dye much less efficiently at 24 h, in a manner dependent on PKC. However, keratinocyte migration to fill the scratch required early (within <6 h) gap junctional communication. Our evidence indicates that PKC-dependent phosphorylation of Cx43 at S368 creates dynamic communication compartments that can temporally and spatially regulate wound healing. PMID:15534005

Richards, Theresa S.; Dunn, Clarence A.; Carter, William G.; Usui, Marcia L.; Olerud, John E.; Lampe, Paul D.

2004-01-01

101

Evaluation of oxidative stress in D-serine induced nephrotoxicity.  

PubMed

It has been suggested that oxidative stress is involved in d-serine-induced nephrotoxicity. The purpose of this study was to assess if oxidative stress is involved in this experimental model using several approaches including (a) the determination of several markers of oxidative stress and the activity of some antioxidant enzymes in kidney and (b) the use of compounds with antioxidant or prooxidant effects. Rats were sacrificed at several periods of time (from 3 to 24h) after a single i.p. injection of d-serine (400mg/kg). Control rats were injected with l-serine (400mg/kg) and sacrificed 24h after. The following markers were used to assess the temporal aspects of renal damage: (a) urea nitrogen (BUN) and creatinine in blood serum, (b) kidney injury molecule (KIM-1) mRNA levels, and (c) tubular necrotic damage. In addition, creatinine clearance, proteinuria, and urinary excretion of N-acetyl-beta-d-glucosaminidase (NAG) were measured 24h after d-serine injection. Protein carbonyl content, malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE), fluorescent products of lipid peroxidation, reactive oxygen species (ROS), glutathione (GSH) content, and heme oxygenase-1 (HO-1) expression were measured as markers of oxidative stress in the kidney. Additional experiments were performed using the following compounds with antioxidant or pro-oxidant effects before d-serine injection: (a) alpha-phenyl-tert-butyl-nitrone (PBN), a spin trapping agent; (b) 5,10,15,20-tetrakis (4-sulfonatophenyl) porphyrinato iron(III) (FeTPPS), a soluble complex able to metabolize peroxynitrite; (c) aminotriazole (ATZ), a catalase (CAT) inhibitor; (d) stannous chloride (SnCl(2)), an HO-1 inductor; (e) tin mesoporphyrin (SnMP), an HO inhibitor. In the time-course study, serum creatinine and BUN increased significantly on 15-24 and 20-24h, respectively, and KIM-1 mRNA levels increased significantly on 6-24h. Histological analyses revealed tubular necrosis at 12h. The activity of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase remained unchanged at all times studied. Protein carbonyl content, MDA, 4-HNE, and ROS remained unchanged at all time-points studied. GSH content decreased transiently on 9 and 12h. Interestingly, fluorescent products of lipid peroxidation decreased significantly on 3-24h. HO-1 expression was undetectable by Western blot and the immunohistochemistry studies revealed that the intensity of HO-1 staining was weak. The administration of PBN, FeTPPS, ATZ, SnCl(2), and SnMP did not prevent or enhance renal damage induced by d-serine. Our data taken as a whole suggest that oxidative stress is not involved in the early phase of the nephrotoxicity induced by d-serine. PMID:17110013

Orozco-Ibarra, Marisol; Medina-Campos, Omar Noel; Sánchez-González, Dolores Javier; Martínez-Martínez, Claudia María; Floriano-Sánchez, Esaú; Santamaría, Abel; Ramirez, Victoria; Bobadilla, Norma A; Pedraza-Chaverri, José

2007-01-01

102

Plasma motion during the formation phase of the PS-3 and PS-3. 5 spheromaks  

SciTech Connect

Spectroscopic Doppler-shift measurements of C III impurity ion in the ultraviolet are reported from the University of Maryland spheromak experiments PS-3 ad PS-3.5. A new time- and space-resolved Doppler-shift diagnostic with absolute wavelength calibration to +/- 0.02 A is described. Large-velocity fields (on the order of the Alfven speed) observed in both the PS-3 and PS-3.5 experiments during the formation phase, but not during the equilibrium, suggest that flow fields may play an important role in the reconnection and relaxation process. The standard theory of Taylor relaxation may need to be modified in order to include the effects of bulk plasma motion. Doppler-shift measurements of the C III 2296.87-A impurity-emission line in the PS-3.5 spheromak were made side-on above and below the machine axis. During the formation phase, blue shifts are observed below and red shifts observed above the axis suggesting a toroidal rotation in the direction of the confined-plasma diamagnetic drift. The plasma emissivity near the C III wavelength was obtained from Abel inversion of the line-integrated intensities. Computer modeling of velocity fields, emissivity profiles, and line shapes is used to interpret the experimental data.

Peyser, T.A.

1987-01-01

103

PAN/PS elctrospun fibers for oil spill cleanup  

NASA Astrophysics Data System (ADS)

A high-capacity oil sorbent was fabricated by electrospinning using PS/PAN blend. Morphology, contact angle and oil adsorption of PAN/PS fiber and PP nonwoven fabric were studied. It was found that the PAN/PS fiber had a smaller diameter than PP, and the maximum sorption capacities of the PAN/PS sorbent for pump oil, peanut oil, diesel, and gasoline were 194.85, 131.7, 66.75, and 43.38 g/g, which were far higher than those of PP. The sorbent PS/PAN fiber showed a contact angle of water144.32° and diesel oil 0°. The sorption kinetics of PAN/PS and PP sorbent were also investigated. Compared with the commercial PP fabric, the PAN/PS fiber seems to have the ability to be used in oil-spill cleanup application.

Ying, Qiao; Lili, Zhao; Haixiang, Sun; Peng, Li

2014-08-01

104

Characterization of a chemostable serine alkaline protease from Periplaneta americana  

PubMed Central

Background Proteases are important enzymes involved in numerous essential physiological processes and hold a strong potential for industrial applications. The proteolytic activity of insects’ gut is endowed by many isoforms with diverse properties and specificities. Thus, insect proteases can act as a tool in industrial processes. Results In the present study, purification and properties of a serine alkaline protease from Periplaneta americana and its potential application as an additive in various bio-formulations are reported. The enzyme was purified near to homogeneity by using acetone precipitation and Sephadex G-100 gel filtration chromatography. Enzyme activity was increased up to 4.2 fold after gel filtration chromatography. The purified enzyme appeared as single protein-band with a molecular mass of?~?27.8 kDa in SDS-PAGE. The optimum pH and temperature for the proteolytic activity for purified protein were found around pH 8.0 and 60°C respectively. Complete inhibition of the purified enzyme by phenylmethylsulfonyl fluoride confirmed that the protease was of serine-type. The purified enzyme revealed high stability and compatibility towards detergents, oxidizing, reducing, and bleaching agents. In addition, enzyme also showed stability towards organic solvents and commercial detergents. Conclusion Several important properties of a serine protease from P. Americana were revealed. Moreover, insects can serve as excellent and alternative source of industrially important proteases with unique properties, which can be utilized as additives in detergents, stain removers and other bio-formulations. Properties of the P. americana protease accounted in the present investigation can be exploited further in various industrial processes. As an industrial prospective, identification of enzymes with varying essential properties from different insect species might be good approach and bioresource. PMID:24229392

2013-01-01

105

Structural, mechanistic and regulatory studies of serine palmitoyltransferase.  

PubMed

SLs (sphingolipids) are composed of fatty acids and a polar head group derived from L-serine. SLs are essential components of all eukaryotic and many prokaryotic membranes but S1P (sphingosine 1-phosphate) is also a potent signalling molecule. Recent efforts have sought to inventory the large and chemically complex family of SLs (LIPID MAPS Consortium). Detailed understanding of SL metabolism may lead to therapeutic agents specifically directed at SL targets. We have studied the enzymes involved in SL biosynthesis; later stages are species-specific, but all core SLs are synthesized from the condensation of L-serine and a fatty acid thioester such as palmitoyl-CoA that is catalysed by SPT (serine palmitoyltransferase). SPT is a PLP (pyridoxal 5'-phosphate)-dependent enzyme that forms 3-KDS (3-ketodihydrosphingosine) through a decarboxylative Claisen-like condensation reaction. Eukaryotic SPTs are membrane-bound multi-subunit enzymes, whereas bacterial enzymes are cytoplasmic homodimers. We use bacterial SPTs (e.g. from Sphingomonas) to probe their structure and mechanism. Mutations in human SPT cause a neuropathy [HSAN1 (hereditary sensory and autonomic neuropathy type 1)], a rare SL metabolic disease. How these mutations perturb SPT activity is subtle and bacterial SPT mimics of HSAN1 mutants affect the enzyme activity and structure of the SPT dimer. We have also explored SPT inhibition using various inhibitors (e.g. cycloserine). A number of new subunits and regulatory proteins that have a direct impact on the activity of eukaryotic SPTs have recently been discovered. Knowledge gained from bacterial SPTs sheds some light on the more complex mammalian systems. In the present paper, we review historical aspects of the area and highlight recent key developments. PMID:22616865

Lowther, Jonathan; Naismith, James H; Dunn, Teresa M; Campopiano, Dominic J

2012-06-01

106

Insulin resistance and muscle insulin receptor substrate-1 serine hyperphosphorylation.  

PubMed

Insulin resistance in metabolic syndrome subjects is profound in spite of muscle insulin receptor and insulin-responsive glucose transporter (GLUT4) expression being nearly normal. Insulin receptor tyrosine kinase phosphorylation of insulin receptor substrate-1 (IRS-1) at Tyr896 is a necessary step in insulin stimulation of translocation of GLUT4 to the cell surface. Serine phosphorylation of IRS-1 by some kinases diminishes insulin action in mice. We evaluated the phosphorylation status of muscle IRS-1 in 33 subjects with the metabolic syndrome and seventeen lean controls. Each underwent euglycemic insulin clamps and a thigh muscle biopsy before and after 8 weeks of either strength or endurance training. Muscle IRS-1 phosphorylation at six sites was quantified by immunoblots. Metabolic syndrome muscle IRS-1 had excess phosphorylation at Ser337 and Ser636 but not at Ser307, Ser789, or Ser1101. Ser337 is a target for phosphorylation by glycogen synthase kinase 3 (GSK3) and Ser636 is phosphorylated by c-Jun N-terminal kinase 1 (JNK1). Exercise training without weight loss did not change the IRS-1 serine phosphorylation. These data suggest that baseline hyperphosphorylation of at least two key serines within muscle IRS-1 diminishes the transmission of the insulin signal and thereby decreases the insulin-stimulated translocation of GLUT4. Excess fasting phosphorylation of muscle IRS-1 at Ser636 may be a major cause of the insulin resistance seen in obesity and might prevent improvement in insulin responsiveness when exercise training is not accompanied by weight loss. PMID:25472611

Stuart, Charles A; Howell, Mary E A; Cartwright, Brian M; McCurry, Melanie P; Lee, Michelle L; Ramsey, Michael W; Stone, Michael H

2014-12-01

107

New L-Serine Derivative Ligands as Cocatalysts for Diels-Alder Reaction  

PubMed Central

New L-serine derivative ligands were prepared and tested as cocatalyst in the Diels-Alder reactions between cyclopentadiene (CPD) and methyl acrylate, in the presence of several Lewis acids. The catalytic potential of the in situ formed complexes was evaluated based on the reaction yield. Bidentate serine ligands showed good ability to coordinate medium strength Lewis acids, thus boosting their catalytic activity. The synthesis of the L-serine ligands proved to be highly efficient and straightforward. PMID:24383009

Sousa, Carlos A. D.; Rodríguez-Borges, José E.; Freire, Cristina

2013-01-01

108

Increased liver l-serine–pyruvate aminotransferase activity under gluconeogenic conditions (Short Communication)  

PubMed Central

Rat liver l-serine–pyruvate aminotransferase activity exceeds markedly the normal adult value (a) in the neonatal period, (b) after glucagon injection and (c) after alloxan injection, observations that reinforce the suggestion from comparative findings that the aminotransferase has a role in gluconeogenesis. Some findings, however, argue in favour of l-serine dehydratase as the enzyme of gluconeogenesis from l-serine. PMID:4723229

Rowsell, Edward V.; Al-Tai, Ali H.; Carnie, John A.; Rowsell, Kathleen V.

1973-01-01

109

FRAP-Dependent Serine Phosphorylation of IRS-1 Inhibits IRS-1 Tyrosine Phosphorylation  

Microsoft Academic Search

We have previously shown that interferon-? (IFN?)-dependent tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) is impaired by serine phosphorylation of IRS-1 due to the reduced ability of serine phosphorylated IRS-1 to serve as a substrate for Janus kinase 1 (JAK1). Here we report that FKBP12–rapamycin-associated protein (FRAP) is a physiologic IRS-1 kinase that blocks IFN? signaling by serine phosphorylating IRS-1.

Matthew E. Hartman; Montserrat Villela-Bach; Jie Chen; Gregory G. Freund

2001-01-01

110

Pharmacokinetics of Oral d-Serine in d-Amino Acid Oxidase Knockout Mice  

PubMed Central

d-Amino acid oxidase (DAAO) catalyzes the oxidative deamination of d-amino acids including d-serine, a full agonist at the glycine modulatory site of the N-methyl-d-aspartate (NMDA) receptor. To evaluate the significance of DAAO-mediated metabolism in the pharmacokinetics of oral d-serine, plasma d-serine levels were measured in both wild-type mice and transgenic mice lacking DAAO. Although d-serine levels were rapidly diminished in wild-type mice (t½ = 1.2 h), sustained drug levels over the course of 4 h (t½ > 10 h) were observed in mice lacking DAAO. Coadministration of d-serine with 6-chlorobenzo[d]isoxazol-3-ol (CBIO), a small-molecule DAAO inhibitor, in wild-type mice resulted in the enhancement of plasma d-serine levels, although CBIO seems to have only temporary effects on the plasma d-serine levels due to glucuronidation of the key hydroxyl group. These findings highlight the predominant role of DAAO in the clearance of d-serine from the systemic circulation. Thus, a potent DAAO inhibitor with a longer half-life should be capable of maintaining high plasma d-serine levels over a sustained period of time and might have therapeutic implications for the treatment of schizophrenia. PMID:22837388

Rais, Rana; Thomas, Ajit G.; Wozniak, Krystyna; Wu, Ying; Jaaro-Peled, Hanna; Sawa, Akira; Strick, Christine A.; Engle, Sandra J.; Brandon, Nicholas J.; Rojas, Camilo; Slusher, Barbara S.

2012-01-01

111

Phylogenetic analysis of serine proteases from Russell's viper (Daboia russelli siamensis) and Agkistrodon piscivorus leucostoma venom  

PubMed Central

Serine proteases are widely found in snake venoms. They have variety of functions including contributions to hemostasis. In this study, five serine proteases were cloned and characterized from two different cDNA libraries: factor V activator (RVV-V), alpha fibrinogenase (RVAF) and beta fibrinogenase (RVBF) from Russell's viper (Daboia russelli siamensis), and plasminogen activator (APL-PA) and protein C activator (APL-C) from Agkistrodon piscivorus leucostoma. The snake venom serine proteases were clustered in phylogenetic tree according to their functions. KA/KS values suggested that accelerated evolution has occurred in the mature protein coding regions in cDNAs of snake venom serine proteases. PMID:21640745

Sukkapan, Pattadon; Jia, Ying; Nuchprayoon, Issarang; Pérez, John C.

2012-01-01

112

Internal gastargets in AmPS  

NASA Astrophysics Data System (ADS)

Internal gas targets in AmPS A.P. Kaan, O. Postma, J.F.J. van den Brand, E. van Leeuwen, M. Doets, M. Kra= an National Institute for Nuclear Physics and High Energy Physics; Kruislaan 409; 1098 SJ Amsterdam; Holland In the Amsterdam Puls Stretcher/storage ring AmPS(1 GeV electrons), we designed a set-up in order to accommodate a gas target with a density of 1016 mol/cm2. The storage cell needed for this purpose is a aluminium tube with a length of 40 cm, a diameter of 15 mm and a wall thickness of 25 =B5m. Three sets of conductance limiters on both sides of the target, combined with dry turbopumps are designed to be used as differential pumping stations. These limiters cause discontinuities in the beam path and must therefor be retractable and radio frequency compatible in both positions. Low =B5 materials must be used because of the depolarisation effects of changing magnetic fields. The calculations show that the flow resistance's are sufficient to reduce the load of the getter pumps to a level with which the lifetime of the pump elements remain acceptable. The design of the mechanics and the vacuum system will be explained. Recent results from the measurements after installation in combination with the influence on the lifetime on the beam will be presented

Kaan, A. P.; Postma, O.; van den Brand, J. F. J.; van Leeuwen, E.; Doets, M.; Kraan, M.

1997-05-01

113

A novel Candida glabrata cell wall associated serine protease.  

PubMed

We set out to identify the Candida glabrata cell wall attached proteases which may play a role as virulence factors in candidosis, particularly in the immunocompromized host. We studied a clinical C. glabrata strain T-1639, which was isolated from a patient from the Helsinki University Central Hospital. With non-reducing 2-D electrophoresis using parallel fluorogenic gels and mass spectrometry we identified a novel appr. 25 kDa (192 aa in length) cell wall located protease with an estimated pI of 7.6. The LC-MS/MS peptides matched with the ORF of predicted C. glabrata CBS138 cell wall protein Cwp1.2p/pI 7.7/212 aa (http://cbi.labri.fr/Génolevures/[NCBI access 49525604, UniProt access Q6FTZ7]), which is an ortholog to Saccharomyces cerevisiae cell wall protein Cwp1p (UniProt access P28319). The novel serine protease was released by ?-1,3-glucanase treatment from the cell wall. In contrast to previous predictions this protease has an enzymatic function instead of being merely a structural cell wall protein. The protease showed gelatinolytic activity and was inhibited by PMSF, a known serine protease inhibitor. Further characterization of the protease may give insight to its role in infections caused by C. glabrata and possibly aid in the development of new kinds of antifungal drugs. PMID:25617734

Pärnänen, Pirjo; Meurman, Jukka H; Nikula-Ijäs, Pirjo

2015-02-20

114

Antibacterial activity of silver nanoparticles synthesized from serine.  

PubMed

Silver nanoparticles (Ag NPs) were synthesized by a simple microwave irradiation method using polyvinyl pyrrolidone (PVP) as a capping agent and serine as a reducing agent. UV-Visible spectra were used to confirm the formation of Ag NPs by observing the surface plasmon resonance (SPR) band at 443nm. The emission spectrum of Ag NPs showed an emission band at 484nm. In the presence of microwave radiation, serine acts as a reducing agent, which was confirmed by Fourier transformed infrared (FT-IR) spectrum. High-resolution transmission electron microscopy (HR-TEM) and high-resolution scanning electron microscopy (HR-SEM) were used to investigate the morphology of the synthesized sample. These images showed the sphere-like morphology. The elemental composition of the sample was determined by the energy dispersive X-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NPs. The electrochemical behavior of the synthesized Ag NPs was analyzed by the cyclic voltammetry (CV). Antibacterial experiments showed that the prepared Ag NPs showed relatively similar antibacterial activities, when compared with AgNO3 against Gram-positive and Gram-negative bacteria. PMID:25686955

Jayaprakash, N; Judith Vijaya, J; John Kennedy, L; Priadharsini, K; Palani, P

2015-04-01

115

Biochemical characterization of Acacia schweinfurthii serine proteinase inhibitor.  

PubMed

One of the many control mechanisms of serine proteinases is their specific inhibition by protein proteinase inhibitors. An extract of Acacia schweinfurthii was screened for potential serine proteinase inhibition. It was successfully purified to homogeneity by precipitating with 80% (v/v) acetone and sequential chromatographic steps, including ion-exchange, affinity purification and reversed-phase high performance liquid chromatography. Reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis conditions revealed an inhibitor (ASTI) consisting of two polypeptide chains A and B of approximate molecular weights of 16 and 10?kDa, respectively, and under non-reducing conditions, 26?kDa was observed. The inhibitor was shown to inhibit bovine trypsin (Ki of 3.45?nM) at an approximate molar ratio of inhibitor:trypsin (1:1). The A- and B-chains revealed complete sequences of 140 and 40 amino acid residues, respectively. Sequence similarity (70%) was reported between ASTI A-chain and ACTI A-chain (Acacia confusa) using ClustalW. The B-chain produced a 76% sequence similarity between ASTI and Leucaena leucocephala trypsin inhibitor. PMID:24090421

Odei-Addo, Frank; Frost, Carminita; Smith, Nanette; Ogawa, Tomohisa; Muramoto, Koji; Oliva, Maria Luiza Vilela; Gráf, László; Naude, Ryno

2014-10-01

116

Expression of the MAST family of serine/threonine kinases.  

PubMed

The Microtubule-Associated Serine/Threonine Kinase family (MAST1-4, and MAST-like) is characterised by the presence of a serine/threonine kinase domain and a postsynaptic density protein-95/discs large/zona occludens-1 domain (PDZ). This latter domain gives the MAST family the capacity to scaffold its own kinase activity. In the present study we have profiled the mRNA for each member of the MAST family transcripts across various tissues, with particular focus on rodent brain. Reverse-transcriptase polymerase chain reaction (RT-PCR) has shown equivalent patterns of expression for MAST1 and 2 in multiple tissues. Both MAST3 and 4 show more distinct expression in several tissues, and MAST-like appears to be predominantly expressed in heart and testis. In situ hybridisation reveals overlapping expression of MAST1 and 2 in specific brain regions. In contrast, MAST3 shows selective expression in the striatum and cerebral cortex. MAST4 also exhibits distinct expression in oligodendrocytes of white matter containing brain regions. In keeping with previous results, this family member also shows increased expression in the hippocampus following seizure-like activity. Our analysis of MAST family expression provides support for the role of these kinases in a broad range of neural functions. PMID:18206861

Garland, Patrick; Quraishe, Shmma; French, Pim; O'Connor, Vincent

2008-02-21

117

Cellular serine/threonine phosphatase activity during human cytomegalovirus infection.  

PubMed

While the importance of cellular and viral kinases in HCMV replication has been demonstrated, relatively little is known about the activity of cellular phosphatases. We conducted a series of experiments designed to investigate the effect of HCMV infection on cellular serine/threonine phosphatase activity. We found that the abundance of two major cellular serine/threonine phosphatases, PP1 and PP2A, increases during HCMV infection. This was associated with an increase in threonine phosphatase activity in HCMV-infected cells. HCMV infection conferred resistance to the effects of the phosphatase inhibitors calyculin A (CA) and okadaic acid with regards to global protein hyperphosphorylation and the shutoff of protein synthesis. The protective effect of HCMV infection could be overcome at a high concentration of CA, suggesting that cellular phosphatase activity is required for critical cellular processes during HCMV infection. Specifically, phosphatase activity was required to limit the accumulation of phospho-eIF2alpha, but not phospho-PKR, during HCMV infection. PMID:18757073

Hakki, Morgan; Geballe, Adam P

2008-10-25

118

S-Wave Shape Resonances in the Ps- System  

NASA Astrophysics Data System (ADS)

We have investigated the S-wave shape resonance states of the positronium negative ion (Ps-) system. The resonance poles are traced from H- system to Ps- by systematically varying the mass of the positively charged particle from infinitely heavy to one unit of the electron mass. The shape resonances that associated with and lying above the Ps( N = 2, 3, 4 and 5) thresholds are located by employing the complex-coordinate rotation method with highly correlated Hylleraas-type wave functions. It has been shown that the Ps-( N = 3) shape resonance lies at an energy which is higher than the Ps( N = 4) thresholds and even the Ps-( N = 4) shape resonance. An explanation was given to shed light on such phenomena.

Jiao, L. G.; Ho, Y. K.

2013-11-01

119

An essential role for de novo biosynthesis of L-serine in CNS development.  

PubMed

L-serine plays a versatile role in intermediary metabolism in eukaryotic cells. The physiological significance of its de novo biosynthesis, however, remains largely unexplored. We demonstrated previously that neurons lose the ability to synthesize L-serine after their final differentiation and thus depend on astrocytes to supply this amino acid. This is due to a lack of neuronal expression of 3-phosphoglycerate dehydrogenase (Phgdh), which initiates de novo L-serine synthesis via the phosphorylated pathway from the glycolytic intermediate 3-phosphoglycerate. In rodent brain, Phgdh is expressed exclusively by the neuroepithelium/radial glia/astrocyte lineage. In humans, serine deficiency disorders can result from a deficiency of Phgdh or other enzymes involved in serine biosynthesis in the phosphorylated pathway. Patients with such disorders have lower serine levels in plasma and cerebrospinal fluid; they exhibit severe neurological symptoms including congenital microcephaly, feeding disabilities, and psychomotor retardation. L-serine supplementation can attenuate developmental defects in these patients. To define the physiological importance of de novo L-serine production, we generated Phgdh knockout mice using targeted gene disruption technique. Phgdh deletion drastically reduced serine and glycine levels in the body. Phgdh knockout mice exhibited overall growth retardation with severe brain malformation, culminating in embryonic lethality. These observations highlight the vital role of de novo L-serine synthesis in the formation and function of the mammalian central nervous system. Furthermore, the embryonic lethal phenotype of Phgdh knockouts indicates that L-serine must be synthesized endogenously in mouse (and probably humans) during embryonic development. PMID:18296366

Furuya, Shigeki

2008-01-01

120

Two systems in vitro that show insulin-stimulated serine kinase activity towards the insulin receptor.  

PubMed Central

Two systems in vitro are described that show insulin-stimulated phosphorylation of the insulin receptor on serine residues. In the first system, insulin receptor was purified partially from Fao rat hepatoma cells by direct solubilization of the cells in Triton X-100 and chromatography on wheat-germ-agglutinin-agarose. Phosphorylation of these preparations with [gamma-32P]ATP in the presence or absence of insulin resulted in 32P incorporation exclusively into phosphotyrosine residues. Serine kinase activity towards the insulin receptor was reconstituted by adding extracts of Fao cells. Prior exposure of the cells to insulin stimulated serine kinase activity towards the insulin receptor in extracts 7.2-fold. A receptor serine kinase activity enhanced by treatment of cells with cyclic AMP analogues was also retained in the reconstituted system. In the second system, insulin receptor and insulin-sensitive serine kinase activity towards the insulin receptor were co-purified from human placenta. The protocol involved preparation of membranes, before solubilization and chromatography on wheat-germ-agglutinin-agarose, by using gentle procedures designed not to disrupt a potentially labile association between the insulin receptor and the serine kinase. Serine kinase activity in these preparations towards the insulin receptor was stimulated up to 10-fold by insulin, and the stoicheiometry of serine phosphorylation was estimated to be approx 0.8 mol/mol of insulin receptor for phosphorylations performed in the presence of insulin. Thus a preparation of insulin receptor is described for the first time that is phosphorylated to high stoicheiometry on serine in an insulin-dependent manner. Conditions that facilitate recovery and assay of serine kinase activity are defined and discussed. These systems provide a basis for characterizing the nature of the insulin-sensitive serine kinase that phosphorylates the insulin receptor, and defining its role in insulin action and control of receptor function. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:2965579

Smith, D M; King, M J; Sale, G J

1988-01-01

121

Energy and expectation values of the PsH system  

SciTech Connect

Close to converged energies and expectation values for PsH are computed using a ground state wave function consisting of 1800 explicitly correlated gaussians. The best estimate of the Ps{sup {infinity}}H energy was -0.789 196 740 hartree which is the lowest variational energy to date. The 2{gamma} annihilation rate for Ps{sup {infinity}}H was 2.471 78x10{sup 9} s{sup -1}.

Mitroy, J. [Faculty of Technology, Charles Darwin University, Darwin NT 0909 (Australia)

2006-05-15

122

PS: A nonprocedural language with data types and modules  

NASA Technical Reports Server (NTRS)

The Problem Specification (PS) nonprocedural language is a very high level language for algorithm specification. PS is suitable for nonprogrammers, who can specify a problem using mathematically-oriented equations; for expert programmers, who can prototype different versions of a software system for evaluation; and for those who wish to use specifications for portions (if not all) of a program. PS has data types and modules similar to Modula-2. The compiler generates C code. PS is first shown by example, and then efficiency issues in scheduling and code generation are discussed.

Gokhale, M. B.

1986-01-01

123

Distinct iPS Cells Show Different Cardiac Differentiation Efficiency  

PubMed Central

Patient-specific induced pluripotent stem (iPS) cells can be generated by introducing transcription factors that are highly expressed in embryonic stem (ES) cells into somatic cells. This opens up new possibilities for cell transplantation-based regenerative medicine by overcoming the ethical issues and immunological problems associated with ES cells. Despite the development of various methods for the generation of iPS cells that have resulted in increased efficiency, safety, and general versatility, it remains unknown which types of iPS cells are suitable for clinical use. Therefore, the aims of the present study were to assess (1) the differentiation potential, time course, and efficiency of different types of iPS cell lines to differentiate into cardiomyocytes in vitro and (2) the properties of the iPS cell-derived cardiomyocytes. We found that high-quality iPS cells exhibited better cardiomyocyte differentiation in terms of the time course and efficiency of differentiation than low-quality iPS cells, which hardly ever differentiated into cardiomyocytes. Because of the different properties of the various iPS cell lines such as cardiac differentiation efficiency and potential safety hazards, newly established iPS cell lines must be characterized prior to their use in cardiac regenerative medicine. PMID:24367382

Yuasa, Shinsuke; Egashira, Toru; Seki, Tomohisa; Hashimoto, Hisayuki; Shimoji, Kenichiro; Kageyama, Toshimi; Tanaka, Tomofumi; Hattori, Fumiyuki; Murata, Mitsushige; Kimura, Kensuke; Fukuda, Keiichi

2013-01-01

124

Distinct iPS Cells Show Different Cardiac Differentiation Efficiency.  

PubMed

Patient-specific induced pluripotent stem (iPS) cells can be generated by introducing transcription factors that are highly expressed in embryonic stem (ES) cells into somatic cells. This opens up new possibilities for cell transplantation-based regenerative medicine by overcoming the ethical issues and immunological problems associated with ES cells. Despite the development of various methods for the generation of iPS cells that have resulted in increased efficiency, safety, and general versatility, it remains unknown which types of iPS cells are suitable for clinical use. Therefore, the aims of the present study were to assess (1) the differentiation potential, time course, and efficiency of different types of iPS cell lines to differentiate into cardiomyocytes in vitro and (2) the properties of the iPS cell-derived cardiomyocytes. We found that high-quality iPS cells exhibited better cardiomyocyte differentiation in terms of the time course and efficiency of differentiation than low-quality iPS cells, which hardly ever differentiated into cardiomyocytes. Because of the different properties of the various iPS cell lines such as cardiac differentiation efficiency and potential safety hazards, newly established iPS cell lines must be characterized prior to their use in cardiac regenerative medicine. PMID:24367382

Ohno, Yohei; Yuasa, Shinsuke; Egashira, Toru; Seki, Tomohisa; Hashimoto, Hisayuki; Tohyama, Shugo; Saito, Yuki; Kunitomi, Akira; Shimoji, Kenichiro; Onizuka, Takeshi; Kageyama, Toshimi; Yae, Kojiro; Tanaka, Tomofumi; Kaneda, Ruri; Hattori, Fumiyuki; Murata, Mitsushige; Kimura, Kensuke; Fukuda, Keiichi

2013-01-01

125

d-Serine content and d-[ 3H]serine binding in the brain regions of the senescence-accelerated mouse  

Microsoft Academic Search

An established senescence-accelerated model mouse strain, SAMP8, shows the deterioration of learning and memory compared with a normal control strain, SAMR1. d-Serine binds to strychnine-insensitive glycine binding sites of the N-methyl-d-aspartate (NMDA) receptor complex, and enhances glutamate binding to the receptor complex. To investigate the relationship of endogenous brain d-serine and the brain dysfunction caused by aging, the level of

Yoko Nagata; Takashi Uehara; Yoshihisa Kitamura; Yasuyuki Nomura; Kihachiro Horiike

1998-01-01

126

Plasma Motion during the Formation Phase of the PS-3 and PS-3.5 Spheromaks  

NASA Astrophysics Data System (ADS)

Spectroscopic Doppler shift measurements of a CIII impurity ion in the ultraviolet are reported from the University of Maryland spheromak experiments PS-3 and PS-3.5. A new time and space resolved Doppler shift diagnostic with absolute wavelength calibration to +/- 0.02 A is described. The spheromak is a member of the compact toroid class of magnetic confinement devices. Spheromak formation is thought to proceed through a magnetic reconnection or relaxation process characterized by evolution to a minimum energy equilibrium subject to the constraint that the magnetic helicity is invariant. Large velocity fields (on the order of the Alfven speed) observed in both the PS-3 and PS-3.5 experiments during the formation phase, but not during the equilibrium, suggest that flow fields may play an important role in the reconnection and relaxation process. The standard theory of Taylor relaxation may need to be modified in order to include the effects of bulk plasma motion. Doppler shift measurements of the CIII 2296.87 A impurity emission line in the PS-3.5 spheromak were made side-on above and below the machine axis. During the formation phase, blue shifts are observed below and red shifts observed above the axis suggesting a toroidal rotation in the direction of the confined plasma diamagnetic drift. The plasma emissivity near the CIII wavelength was obtained from Abel inversion of the line-integrated intensities. Computer modelling of velocity fields, emissivity profiles and line shapes is used to interpret the experimental data. Variation of the flow fields as a function of the static fill pressure indicated the possible significance of the density profile to bulk motion of the plasma. A quadarature interferometer was used to obtain the time history of the line-integrated density through two chords of the plasma. Double-floating probe measurements gave the radial component of the electric field. The University of Maryland PS experiments utilize a combined theta and z discharge to produce the spheromak magnetic field configuration. The theory of rotation in theta pinch devices is briefly reviewed and a comparison is made with the results of the present experiment. The theoretical implications of including velocity terms in the energy minimization problem are also discussed. The decay rate of an ideal MHD invariant, the cross helicity, is considered in view of viscous and resistive effects in the experiments.

Peyser, Thomas Arnold

127

PS2004 Light-harvesting Systems Workshop  

SciTech Connect

This special issue of the international scientific research journal Photosynthesis Research consists of 25 original peer-reviewed contributions from participants in the PS 2004 Lisht-Harvesting Systems Workshop. This workshop was held from 26-29, 2004 at Hotel Le Chantecler, Sainte-Adele, Quebec, Canada. The workshop was a satellite meeting of the XIII International Congress on Photosynthesis held August 29-September 3, 2004 in Montreal, Canada. The workshope dealt with all types of photosynthetic antenna systems and types of organisms, including anoxygenic photosynthetic bacteria, cyanobacteria, algae and higher plants, as well as in vitro studies of isolated pigments. This collection of papers is a good representation of the highly interdisciplinary nature of modern research on photosynthetic antenna complexes, utilizing techniques of advanced spectroscopy, biochemistry, molecular biology, synthetic chemistry and structural determination to understand these diverse and elegant molecular complexes.

Robert E. Blankenship

2005-11-01

128

Drosophila Omi, a mitochondrial-localized IAP antagonist and proapoptotic serine protease  

E-print Network

Drosophila Omi, a mitochondrial-localized IAP antagonist and proapoptotic serine protease Madhavi. Herein, we demon- strate that Drosophila Omi (dOmi), a fly homologue of the serine protease Omi/HtrA2 to the baculovirus IAP repeat 2 (BIR2) domain in Drosophila IAP1 (DIAP1) and displaces the initiator caspase DRONC

Yin, Y. Whitney

129

Novel protein serine\\/threonine phosphatases: Variety is the spice of life  

Microsoft Academic Search

The dephosphorylation of proteins on serine and threonine residues is a major mechanism of cellular regulation. Many novel protein serine\\/threonine phosphatases in the PPP family have recently been discovered and the insights that have been gained into their different functions are summarised in this review.

Patricia T. W. Cohen

1997-01-01

130

The modular serine proteases of the complement cascade.  

PubMed

Modular serine proteases are central to the complement cascade of the mammalian humoral immune system. These proteases form protein complexes through multi-domain interactions to achieve their proteolytic activity. We review the structural insights into complement initiation by auto-activation of the hetero-tetrameric proteases of the large danger-recognition protein complexes, amplification and labelling of particles by the formation and activity of C3 convertases, and regulation by convertase dissociation and degradation to prevent 'bystander' damage to healthy host cells and tissues. The data reveal that complex formation and large domain-domain rearrangements underlie the proteolytic reactions of the complement cascade, which enables the host to recognize and clear invading microbes and host debris from its blood and fluids surrounding tissues. PMID:22560446

Forneris, Federico; Wu, Jin; Gros, Piet

2012-06-01

131

Serine phosphorylation on position 1033 of vinculin impacts cellular mechanics.  

PubMed

This study evaluates the influence of S1033 vinculin phosphorylation on the mechanical properties of cells. We demonstrate that MEFvcl KO cells transfected with the non-phosphorylatable eGFP-vinculin mutant S1033A are of lower stiffness compared to MEFvcl Rescue and phospho-mimicking mutant S1033D cells, which were of similar stiffness. Analogous, 2D traction microscopy indicates that MEFvcl Rescue and MEF mutant S1033D cells generate similar strain energy, but mutant S1033A cells display ?50% less strain energy. Fluorescence recovery after photobleaching demonstrates that the recovery time for mutant S1033A was significantly lower compared to MEFvcl Rescue and mutant S1033D and that the mobile fraction was smaller for MEFvcl Rescue and mutant S1033D than for mutant S1033A cells. This indicates that serine phosphorylation is required for the activation of vinculin and force transmission in focal adhesions. PMID:24996180

Auernheimer, Vera; Goldmann, Wolfgang H

2014-07-25

132

A Self-compartmentalizing Hexamer Serine Protease from Pyrococcus Horikoshii  

PubMed Central

Oligopeptidases impose a size limitation on their substrates, the mechanism of which has long been under debate. Here we present the structure of a hexameric serine protease, an oligopeptidase from Pyrococcus horikoshii (PhAAP), revealing a complex, self-compartmentalized inner space, where substrates may access the monomer active sites passing through a double-gated “check-in” system, first passing through a pore on the hexamer surface and then turning to enter through an even smaller opening at the monomers' domain interface. This substrate screening strategy is unique within the family. We found that among oligopeptidases, a residue of the catalytic apparatus is positioned near an amylogenic ?-edge, which needs to be protected to prevent aggregation, and we found that different oligopeptidases use different strategies to achieve such an end. We propose that self-assembly within the family results in characteristically different substrate selection mechanisms coupled to different multimerization states. PMID:23632025

Menyhárd, Dóra K.; Kiss-Szemán, Anna; Tichy-Rács, Éva; Hornung, Balázs; Rádi, Krisztina; Szeltner, Zoltán; Domokos, Klarissza; Szamosi, Ilona; Náray-Szabó, Gábor; Polgár, László; Harmat, Veronika

2013-01-01

133

A water wire in L-prolyl-L-serine monohydrate.  

PubMed

Despite the extra functional group in the serine side chain, the crystal packing arrangement of the title compound {systematic name: (S)-3-hydroxy-2-[(S)-pyrrolidine-2-carboxamido]propanoic acid monohydrate}, C8H14N2O4·H2O, is essentially the same as observed for a series of L-Pro-L-Nop peptide hydrates, where Nop is a strictly nonpolar residue. This is rendered possible by a monoclinic P2(1) packing arrangement with Z' = 2 that deviates from orthorhombic P2(1)2(1)2(1) symmetry only for the seryl hydroxy groups, which form infinite O-H···O-H hydrogen-bonded chains along the 5.3?Å a axis. At the same time, cocrystallized water molecules form parallel water wires. PMID:23629913

Görbitz, Carl Henrik; Yadav, Vitthal N

2013-05-01

134

L-Serine overproduction with minimization of by-product synthesis by engineered Corynebacterium glutamicum.  

PubMed

The direct fermentative production of L-serine by Corynebacterium glutamicum from sugars is attractive. However, superfluous by-product accumulation and low L-serine productivity limit its industrial production on large scale. This study aimed to investigate metabolic and bioprocess engineering strategies towards eliminating by-products as well as increasing L-serine productivity. Deletion of alaT and avtA encoding the transaminases and introduction of an attenuated mutant of acetohydroxyacid synthase (AHAS) increased both L-serine production level (26.23 g/L) and its productivity (0.27 g/L/h). Compared to the parent strain, the by-products L-alanine and L-valine accumulation in the resulting strain were reduced by 87 % (from 9.80 to 1.23 g/L) and 60 % (from 6.54 to 2.63 g/L), respectively. The modification decreased the metabolic flow towards the branched-chain amino acids (BCAAs) and induced to shift it towards L-serine production. Meanwhile, it was found that corn steep liquor (CSL) could stimulate cell growth and increase sucrose consumption rate as well as L-serine productivity. With addition of 2 g/L CSL, the resulting strain showed a significant improvement in the sucrose consumption rate (72 %) and the L-serine productivity (67 %). In fed-batch fermentation, 42.62 g/L of L-serine accumulation was achieved with a productivity of 0.44 g/L/h and yield of 0.21 g/g sucrose, which was the highest production of L-serine from sugars to date. The results demonstrated that combined metabolic and bioprocess engineering strategies could minimize by-product accumulation and improve L-serine productivity. PMID:25434811

Zhu, Qinjian; Zhang, Xiaomei; Luo, Yuchang; Guo, Wen; Xu, Guoqiang; Shi, Jinsong; Xu, Zhenghong

2014-12-01

135

Inhibition of pan-class I phosphatidyl-inositol-3-kinase by NVP-BKM120 effectively blocks proliferation and induces cell death in diffuse large B-cell lymphoma.  

PubMed

Diffuse large B-cell lymphoma (DLBCL) is the most frequent aggressive lymphoma, with a great demand for novel treatments for relapsing and refractory disease. Constitutive activation of the phosphatidyl-inositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway is often detected in this lymphoma. Inhibition of this signaling cascade with the pan-class I PI3K inhibitor NVP-BKM120 decreased cell proliferation and increased apoptotic cell death. DLBCL proliferation was further decreased if NVP-BKM120-induced autophagy was blocked. Treatment with NVP-BKM120 was associated with an increase of the pro-apoptotic BH3-only proteins Puma and Bim and down-regulation of the anti-apoptotic Bcl-xL and Mcl-1. Translation of Bcl-xL and Mcl-1 is facilitated by cap-dependent mRNA translation, a process that was partially inhibited by NVP-BKM120. Overall, we demonstrated here the potential of NVP-BKM120 for the treatment of DLBCL. PMID:23721513

Zang, Chuanbing; Eucker, Jan; Liu, Hongyu; Coordes, Annekatrin; Lenarz, Minoo; Possinger, Kurt; Scholz, Christian Wilfried

2014-02-01

136

1 / 5 iPS CiRA 2014 11 20  

E-print Network

CiRA 1 / 5 iPS CiRA 2014 11 20 iPS (CiRA) --(iCeMS) JST iPS 1 TALEN CRISPR 1) DMD iPS iPS CiRA CiRA iPS TALEN CRISPR iPS 30 DNA 1 3 Exon 45 skippingReading frame #12;CiRA 2 / 5 iPS CiRA loss-of-function( ) 79 2) 3) () TALEN CRISPR iPS CRISPR HIV

Takada, Shoji

137

New insights into the evolution of subtilisin-like serine protease genes in Pezizomycotina  

PubMed Central

Background Subtilisin-like serine proteases play an important role in pathogenic fungi during the penetration and colonization of their hosts. In this study, we perform an evolutionary analysis of the subtilisin-like serine protease genes of subphylum Pezizomycotina to find if there are similar pathogenic mechanisms among the pathogenic fungi with different life styles, which utilize subtilisin-like serine proteases as virulence factors. Within Pezizomycotina, nematode-trapping fungi are unique because they capture soil nematodes using specialized trapping devices. Increasing evidence suggests subtilisin-like serine proteases from nematode-trapping fungi are involved in the penetration and digestion of nematode cuticles. Here we also conduct positive selection analysis on the subtilisin-like serine protease genes from nematode-trapping fungi. Results Phylogenetic analysis of 189 subtilisin-like serine protease genes from Pezizomycotina suggests five strongly-supported monophyletic clades. The subtilisin-like serine protease genes previously identified or presumed as endocellular proteases were clustered into one clade and diverged the earliest in the phylogeny. In addition, the cuticle-degrading protease genes from entomopathogenic and nematode-parasitic fungi were clustered together, indicating that they might have overlapping pathogenic mechanisms against insects and nematodes. Our experimental bioassays supported this conclusion. Interestingly, although they both function as cuticle-degrading proteases, the subtilisin-like serine protease genes from nematode-trapping fungi and nematode-parasitic fungi were not grouped together in the phylogenetic tree. Our evolutionary analysis revealed evidence for positive selection on the subtilisin-like serine protease genes of the nematode-trapping fungi. Conclusions Our study provides new insights into the evolution of subtilisin-like serine protease genes in Pezizomycotina. Pezizomycotina subtilisins most likely evolved from endocellular to extracellular proteases. The entomopathogenic and nematode-parasitic fungi likely share similar properties in parasitism. In addition, our data provided better understanding about the duplications and subsequent functional divergence of subtilisin-like serine protease genes in Pezizomycotina. The evidence of positive selection detected in the subtilisin-like serine protease genes of nematode-trapping fungi in the present study suggests that the subtilisin-like serine proteases may have played important roles during the evolution of pathogenicity of nematode-trapping fungi against nematodes. PMID:20211028

2010-01-01

138

Effects of Serine Protease Inhibitors on Growth and Development and Digestive Serine Proteinases of the Sunn Pest, Eurygaster integriceps  

PubMed Central

In the current study the effects of serine proteinase inhibitors (TLCK, TPCK, SBTI, and a combination of SBTI and TPCK) with concentrations of 1% and 4% of dietary protein in artificial diets were tested against growth of the Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), development, and its gut serine proteinase targets. Analysis of variance indicated that protease inhibitors affected nymphal development time, adult weight, and survival. Mean development time of third instar nymphs in control, SBTI (1%), TLCK (1%), and TPCK was 7.18, 9.74, 9.97, and 8.52 days, respectively. The highest mortality (100 % mortality) was observed when a combination of TPCK and SBTI, both at 4% of dietary protein, was used followed by TPCK (4%) that produced 95% mortality. There were significant differences in proteinase activity between treatments and controls when BApNA and SAAPFpNA were used as substrates for trypsin and chymotrypsin, respectively. Reduction of trypsin activity in insects fed with low doses of SBTI (1%), TLCK (1%), and both doses of TPCK (1% and 4%) was 40, 26, 23, and 17%, respectively. Inhibition of chymotrypsin activity was seen in the insects fed on SBTI (1%), TLCK (1%), and TPCK (4%) where inhibition was 14, 9, and 36%, respectively. Maximum inhibition of chymotrypsin activity was observed in the insects fed on diets containing high doses of TPCK (4%). In gel assays, the greatest effects were observed when E. integriceps were fed on high doses of SBTI and TPCK. Therefore, TPCK followed by SBTI proved to be the most effective proteinase inhibitors of E. integriceps. PMID:21867440

Saadati, Fatemeh; Bandani, Ali R.

2011-01-01

139

Telomere reprogramming and maintenance in porcine iPS cells.  

PubMed

Telomere reprogramming and silencing of exogenous genes have been demonstrated in mouse and human induced pluripotent stem cells (iPS cells). Pigs have the potential to provide xenotransplant for humans, and to model and test human diseases. We investigated the telomere length and maintenance in porcine iPS cells generated and cultured under various conditions. Telomere lengths vary among different porcine iPS cell lines, some with telomere elongation and maintenance, and others telomere shortening. Porcine iPS cells with sufficient telomere length maintenance show the ability to differentiate in vivo by teratoma formation test. IPS cells with short or dysfunctional telomeres exhibit reduced ability to form teratomas. Moreover, insufficient telomerase and incomplete telomere reprogramming and/or maintenance link to sustained activation of exogenous genes in porcine iPS cells. In contrast, porcine iPS cells with reduced expression of exogenous genes or partial exogene silencing exhibit insufficient activation of endogenous pluripotent genes and telomerase genes, accompanied by telomere shortening with increasing passages. Moreover, telomere doublets, telomere sister chromatid exchanges and t-circles that presumably are involved in telomere lengthening by recombination also are found in porcine iPS cells. These data suggest that both telomerase-dependent and telomerase-independent mechanisms are involved in telomere reprogramming during induction and passages of porcine iPS cells, but these are insufficient, resulting in increased telomere damage and shortening, and chromosomal instability. Active exogenes might compensate for insufficient activation of endogenous genes and incomplete telomere reprogramming and maintenance of porcine iPS cells. Further understanding of telomere reprogramming and maintenance may help improve the quality of porcine iPS cells. PMID:24098638

Ji, Guangzhen; Ruan, Weimin; Liu, Kai; Wang, Fang; Sakellariou, Despoina; Chen, Jijun; Yang, Yang; Okuka, Maja; Han, Jianyong; Liu, Zhonghua; Lai, Liangxue; Gagos, Sarantis; Xiao, Lei; Deng, Hongkui; Li, Ning; Liu, Lin

2013-01-01

140

Proteome-wide reactivity profiling identifies diverse carbamate chemotypes tuned for serine hydrolase inhibition.  

PubMed

Serine hydrolases are one of the largest and most diverse enzyme classes in Nature. Inhibitors of serine hydrolases are used to treat many diseases, including obesity, diabetes, cognitive dementia, and bacterial and viral infections. Nonetheless, the majority of the 200+ serine hydrolases in mammals still lack selective inhibitors for their functional characterization. We and others have shown that activated carbamates, through covalent reaction with the conserved serine nucleophile of serine hydrolases, can serve as useful inhibitors for members of this enzyme family. The extent to which carbamates, however, cross-react with other protein classes remains mostly unexplored. Here, we address this problem by investigating the proteome-wide reactivity of a diverse set of activated carbamates in vitro and in vivo, using a combination of competitive and click chemistry (CC)-activity-based protein profiling (ABPP). We identify multiple classes of carbamates, including O-aryl, O-hexafluoroisopropyl (HFIP), and O-N-hydroxysuccinimidyl (NHS) carbamates that react selectively with serine hydrolases across entire mouse tissue proteomes in vivo. We exploit the proteome-wide specificity of HFIP carbamates to create in situ imaging probes for the endocannabinoid hydrolases monoacylglycerol lipase (MAGL) and ?-? hydrolase-6 (ABHD6). These findings, taken together, designate the carbamate as a privileged reactive group for serine hydrolases that can accommodate diverse structural modifications to produce inhibitors that display exceptional potency and selectivity across the mammalian proteome. PMID:23701408

Chang, Jae Won; Cognetta, Armand B; Niphakis, Micah J; Cravatt, Benjamin F

2013-07-19

141

Overdose of D-serine Induces Movement Disorder and Neuromuscular Changes of Zebrafish Larvae.  

PubMed

D-serine is a well-known activator of N-methyl-D-aspartate receptors; however, little is known about the teratogenic effects of D-serine overdose during early embryonic development. Here, we used zebrafish as a model to test toxicity and teratogenicity, since they have transparent eggs, making the organogenesis of zebrafish embryos easier to be observed. After D-serine injection (100-1000 ppm), the most evident defective phenotypes were bent trunk phenotypes, including malformed somite boundary, twisted body axis and shorter body length. As the injection dosages increased, the rates of embryos with bent trunk phenotypes decreased (0% for 0 ppm, n=573; 59.9~84.3% for 100-1000 ppm of D-serine, n=383-451). In addition, D-serine-injected embryos exhibited significantly reduced the frequencies of spontaneous in-chorion contraction (21.7 for 0 ppm vs. 18.3-0.9 for 100-1000 ppm D-serine, n=30) in comparison with mock-treated controls (0 ppm). Subtle changes are easily observed by staining with specific monoclonal antibodies F59, Znp1, Zn5 and ?-bungarotoxin to detect morphological changes in muscle fibers, primary motor axons, secondary motor axon projections and neuromuscular junctions, respectively. Our data show that overdose of D-serine leads to misalignment of muscle fibers and motor neuron defects, especially secondary motor neuron axonal growth defects. PMID:24791063

Chen, Xing-Guang; Wang, Yun-Hsin; Wen, Chi-Chung; Chen, Yau-Hung

2014-04-01

142

A wavelength tunable 2-ps pulse VECSEL  

NASA Astrophysics Data System (ADS)

We report a mode-locked Vertical-External-Cavity Surface-Emitting Laser (VECSEL) that exhibits 13.7 nm of tuning around a centre wavelength of 1042 nm. The wavelength tuning is achieved by incorporating an uncoated, 25 ?m thick, fused silica etalon into the cavity of the laser at Brewster's angle. The etalon is then tilted with respect to the cavity axis. The etalon has a calculated free spectral range of 14 nm at normal incidence. The repetition rate of the laser is measured to be 1.88 GHz. The pulse duration, averaged over the tuning range, is 1.9 ps corresponding to a mean time bandwidth product of 0.46. For a sech2 pulse this is 1.46 times larger than the transform limit. The average power of the laser does not fall below 2.6 mW and, over the tuning range, averages 3.5 mW. With appropriate amplification, such a laser would be highly suited to the generation of heralded single photons in photonic crystal fibre.

Morris, Oliver J.; Wilcox, Keith G.; Head, C. Robin; Turnbull, Andrew P.; Mosley, Peter J.; Quarterman, Adrian H.; Kbashi, Hani J.; Farrer, Ian; Beere, Harvey E.; Ritchie, David A.; Tropper, Anne C.

2012-03-01

143

Gluconeogenesis from glycine and serine in fasted normal and diabetic rats.  

PubMed Central

1. Non-anaesthetized normal and diabetic rats were fasted for 1 day, and [U-14C]glycine, or [U-14C]serine, or [U-14C]- plus [3-3H]-glucose was injected intra-arterially. The rates of synthesis de novo/irreversible disposal for glycine, serine and glucose, as well as the contribution of carbon atoms by the amino acids to plasma glucose, were calculated from the integrals of the specific-radioactivity-versus-time curves in plasma. 2. The concentrations of both glycine and serine in blood plasma were lower in diabetic than in fasted normal animals. 3. The rates of synthesis de novo/irreversible disposal of both amino acids tended to be lower in diabetic animals, but the decrease was statistically significant only for serine (14.3 compared with 10.5 mumol/min per kg). 4. Of the carbon atoms of plasma glucose, 2.9% arose from glycine in both fasted normal and diabetic rats, whereas 4.46% of glucose carbon originated from serine in fasted normal and 6.77% in diabetic rats. 5. As judged by their specific radioactivities, plasma serine and glycine exchange carbon atoms rapidly and extensively. 6. It was concluded that the turnover of glycine remains essentially unchanged, whereas that of serine is decreased in diabetic as compared with fasted normal rats. The plasma concentration of both amino acids was lower in diabetic rats. Both glycine and serine are glucogenic. In diabetic rats the contribution of carbon atoms from glycine to glucose increases in direct proportion to the increased glucose turnover, whereas the contribution by serine becomes also proportionally higher. PMID:3138983

Hetenyi, G; Anderson, P J; Raman, M; Ferrarotto, C

1988-01-01

144

Metal-ion-assisted hydrolysis of dipeptides involving a serine residue in a neutral aqueous solution.  

PubMed

Dipeptides having a serine residue at the C-terminus, X-Ser, where X is an appropriate amino acid residue, were efficiently hydrolyzed in the presence of ZnCl2 at pH 7.0. The rapid hydrolysis of X-Ser is due to an autocatalysis of the hydroxy group in the serine residue, and is found to be accelerated by a metal ion, in particular by ZnCl2. Roles of the metal ion in the hydrolysis of peptides involving a serine residue, in relation to the recently reported protein cleavages, are discussed. PMID:12929447

Yashiro, Morio; Sonobe, Yoko; Yamamura, Ai; Takarada, Tohru; Komiyama, Makoto; Fujii, Yuki

2003-02-21

145

Quantum-chemical approach to serine formation in the interstellar medium: A possible reaction pathway  

NASA Astrophysics Data System (ADS)

Radical-radical and radical-neutral interaction schemes are very important for the formation of comparatively complex molecules in low-temperature chemistry. The formation of amino acids, such as serine, in the interstellar medium is quite difficult. We explored the possibility of serine formation in the interstellar medium through detected interstellar molecules such as CH, CO, and OH by radical-radical and radical-neutral interactions in the gaseous phase using rigorous quantum-chemical calculations. The reaction energies, the low potential barrier and the structures of all the geometries involved in the reaction path show that serine formation is possible in interstellar space via the reaction paths.

Shivani; Singh, Amresh; Gupta, Vineet; Misra, Alka; Tandon, Poonam

2014-03-01

146

Improvement in Regional CBF by L-Serine Contributes to Its Neuroprotective Effect in Rats after Focal Cerebral Ischemia  

PubMed Central

To investigate the mechanisms underlying the neuroprotective effect of L-serine, permanent focal cerebral ischemia was induced by occlusion of the middle cerebral artery while monitoring cerebral blood flow (CBF). Rats were divided into control and L-serine-treated groups after middle cerebral artery occlusion. The neurological deficit score and brain infarct volume were assessed. Nissl staining was used to quantify the cortical injury. L-serine and D-serine levels in the ischemic cortex were analyzed with high performance liquid chromatography. We found that L-serine treatment: 1) reduced the neurological deficit score, infarct volume and cortical neuron loss in a dose-dependent manner; 2) improved CBF in the cortex, and this effect was inhibited in the presence of apamin plus charybdotoxin while the alleviation of both neurological deficit score and infarct volume was blocked; and 3) increased the amount of L-serine and D-serine in the cortex, and inhibition of the conversion of L-serine into D-serine by aminooxyacetic acid did not affect the reduction of neurological deficit score and infarct volume by L-serine. In conclusion, improvement in regional CBF by L-serine may contribute to its neuroprotective effect on the ischemic brain, potentially through vasodilation which is mediated by the small- and intermediate-conductance Ca2+-activated K+ channels on the cerebral blood vessel endothelium. PMID:23825613

Jiang, Zheng-Lin; Wang, Guo-Hua; Sun, Li; Jiang, Rui; Zhao, Guang-Wei; Han, Le-Yang

2013-01-01

147

Regulation of adrenal aldosterone production by serine protease prostasin.  

PubMed

A serine protease prostasin has been demonstrated to have a pivotal role in the activation of the epithelial sodium channel. Systemic administration of adenovirus carrying human prostasin gene in rats resulted in an increase in plasma prostasin and aldosterone levels. However, the mechanism by which the elevation of prostasin levels in the systemic circulation stimulated the plasma aldosterone levels remains unknown. Therefore, we examined if prostasin increases the aldosterone synthesis in a human adrenocortical cell line (H295R cells). Luciferase assay using CYP11B2 promoter revealed that prostasin significantly increased the transcriptional activity of CYP11B2. Prostasin significantly increased both CYP11B2 mRNA expression and aldosterone production in a dose-dependent manner. Surprisingly, treatment with camostat mesilate, a potent prostasin inhibitor, had no effect on the aldosterone synthesis by prostasin and also a protease-dead mutant of prostasin significantly stimulated the aldosterone production. A T-type/L-type calcium channel blocker and a protein kinase C (PKC) inhibitor significantly reduced the aldosterone synthesis by prostasin. Our findings suggest a stimulatory effect of prostasin on the aldosterone synthesis by adrenal gland through the nonproteolytic action and indicate a new role of prostasin in the systemic circulation. PMID:20204133

Ko, Takehiro; Kakizoe, Yutaka; Wakida, Naoki; Hayata, Manabu; Uchimura, Kohei; Shiraishi, Naoki; Miyoshi, Taku; Adachi, Masataka; Aritomi, Shizuka; Konda, Tomoyuki; Tomita, Kimio; Kitamura, Kenichiro

2010-01-01

148

Regulation of Adrenal Aldosterone Production by Serine Protease Prostasin  

PubMed Central

A serine protease prostasin has been demonstrated to have a pivotal role in the activation of the epithelial sodium channel. Systemic administration of adenovirus carrying human prostasin gene in rats resulted in an increase in plasma prostasin and aldosterone levels. However, the mechanism by which the elevation of prostasin levels in the systemic circulation stimulated the plasma aldosterone levels remains unknown. Therefore, we examined if prostasin increases the aldosterone synthesis in a human adrenocortical cell line (H295R cells). Luciferase assay using CYP11B2 promoter revealed that prostasin significantly increased the transcriptional activity of CYP11B2. Prostasin significantly increased both CYP11B2 mRNA expression and aldosterone production in a dose-dependent manner. Surprisingly, treatment with camostat mesilate, a potent prostasin inhibitor, had no effect on the aldosterone synthesis by prostasin and also a protease-dead mutant of prostasin significantly stimulated the aldosterone production. A T-type/L-type calcium channel blocker and a protein kinase C (PKC) inhibitor significantly reduced the aldosterone synthesis by prostasin. Our findings suggest a stimulatory effect of prostasin on the aldosterone synthesis by adrenal gland through the nonproteolytic action and indicate a new role of prostasin in the systemic circulation. PMID:20204133

Ko, Takehiro; Kakizoe, Yutaka; Wakida, Naoki; Hayata, Manabu; Uchimura, Kohei; Shiraishi, Naoki; Miyoshi, Taku; Adachi, Masataka; Aritomi, Shizuka; Konda, Tomoyuki; Tomita, Kimio; Kitamura, Kenichiro

2010-01-01

149

Interaction of pyridoxal 5-phosphate with apo-serine hydroxymethyltransferase.  

PubMed

The interaction of pyridoxal 5-phosphate with beef liver serine hydroxymethyltransferase (5,10-methylenetetrahydrofolate:glycine hydroxymethyltransferase, EC 2.1.2.1) has been investigated using sedimentation velocity, kinetic and equilibrium techniques. No evidence for an aggregating system could be found in sedimentation velocity experiments in the presence or absence of pyridoxal 5-phosphate. Reassociation of pyridoxal 5-phosphate with apoenzyme and reacquisition of enzymic activity follow identical kinetics. An initial fast step is followed by a second order process with a rate constant of 66 M-1. s-1. A dissociation constant of 27.5 micrometer was obtained from equilibrium studies. No interaction of binding sites was exposed by altering pH or in the presence of glycine or folate. Maxima observed in pH profiles with both binding and reactivation are interpreted as the composite fo two overlapping processes, one of which is ionization of the pyridinium nitrogen of pyridoxal 5-phosphate and the other a functional group on the apoenzyme. Evidence is presented to indicate the necessity for the formation of an enzyme . pyridoxal 5-phosphate Schiff's base complex during catalytic turnover. PMID:31178

Jones, C W; Priest, D G

1978-10-12

150

Phosphorylation at serine 331 is required for Aurora B activation.  

PubMed

Aurora B kinase activity is required for successful cell division. In this paper, we show that Aurora B is phosphorylated at serine 331 (Ser331) during mitosis and that phosphorylated Aurora B localizes to kinetochores in prometaphase cells. Chk1 kinase is essential for Ser331 phosphorylation during unperturbed prometaphase or during spindle disruption by taxol but not nocodazole. Phosphorylation at Ser331 is required for optimal phosphorylation of INCENP at TSS residues, for Survivin association with the chromosomal passenger complex, and for complete Aurora B activation, but it is dispensable for Aurora B localization to centromeres, for autophosphorylation at threonine 232, and for association with INCENP. Overexpression of Aurora B(S331A), in which Ser331 is mutated to alanine, results in spontaneous chromosome missegregation, cell multinucleation, unstable binding of BubR1 to kinetochores, and impaired mitotic delay in the presence of taxol. We propose that Chk1 phosphorylates Aurora B at Ser331 to fully induce Aurora B kinase activity. These results indicate that phosphorylation at Ser331 is an essential mechanism for Aurora B activation. PMID:22024163

Petsalaki, Eleni; Akoumianaki, Tonia; Black, Elizabeth J; Gillespie, David A F; Zachos, George

2011-10-31

151

Phosphorylation at serine 331 is required for Aurora B activation  

PubMed Central

Aurora B kinase activity is required for successful cell division. In this paper, we show that Aurora B is phosphorylated at serine 331 (Ser331) during mitosis and that phosphorylated Aurora B localizes to kinetochores in prometaphase cells. Chk1 kinase is essential for Ser331 phosphorylation during unperturbed prometaphase or during spindle disruption by taxol but not nocodazole. Phosphorylation at Ser331 is required for optimal phosphorylation of INCENP at TSS residues, for Survivin association with the chromosomal passenger complex, and for complete Aurora B activation, but it is dispensable for Aurora B localization to centromeres, for autophosphorylation at threonine 232, and for association with INCENP. Overexpression of Aurora BS331A, in which Ser331 is mutated to alanine, results in spontaneous chromosome missegregation, cell multinucleation, unstable binding of BubR1 to kinetochores, and impaired mitotic delay in the presence of taxol. We propose that Chk1 phosphorylates Aurora B at Ser331 to fully induce Aurora B kinase activity. These results indicate that phosphorylation at Ser331 is an essential mechanism for Aurora B activation. PMID:22024163

Petsalaki, Eleni; Akoumianaki, Tonia; Black, Elizabeth J.; Gillespie, David A.F.

2011-01-01

152

Preliminary Tuft Testing of Metallic Bristles Versus PS212, PS300, and HVOF300  

NASA Technical Reports Server (NTRS)

Turbine engine brush seals are designed with sacrificial brushes and hard shaft coatings to minimize shaft wear and reduce the cost of engine overhauls. Replacing a worm seal is more cost and time effective than refinishing an engine shaft. However, this tribological design causes excessive brush wear and reduces long term seal efficiency. An alternative approach is to coat the shaft with a solid lubricant and allow the bristles to wear into the shaft coating similar to traditional abradable labyrinth seals. This approach can result in reduced seal leakage by forcing the leakage to flow through the seal bristle pack or through a more tortuous shaft wear track. Key to this approach is limiting the shaft wear to an acceptable level were surface refinishing would not be required during every engine overhaul. Included in this paper are brush seal tuft test results for four metallic bristles (nickel-chrome or cobalt-chrome based superalloys) tested against three solid lubricant coatings (NASA's PS212, PS300, and HVOF300). These test results are also compared to previous baseline tests conducted with plasma sprayed chrome carbide. Compared to the baseline results, no tribological benefit was achieved with the metallic bristle/solid lubricant tribopairs tested. To improve the performance of the solid lubricant coatings, issues regarding lubricant phase sizes (homogeneity), and composition need to be addressed.

Fellenstein, James A.; DellaCorte, Christopher

1998-01-01

153

News and Commentary PS externalization: from corpse clearance to drug  

E-print Network

). The ability of PS to act as a signal for in vivo recognition and clearance of effete cells was demonstrated 20-binding bridging molecule, milk fat globule epidermal growth factor 8 (MFG-E8) (also known as lactadherin) results

Xue, Ding

154

Assessment of slope stability using PS-InSAR technique  

NASA Astrophysics Data System (ADS)

In this research work, PS-InSAR approach is envisaged to monitor slope stability of landslides prone areas in Nainital and Tehri region of Uttarakhand, India. For the proposed work, Stanford Method for Persistent Scatterers (StaMPS) based PS-InSAR is used for processing ENVISAT ASAR C-Band data stacks of study area which resulted in a time series 1D-Line of Sight (LOS) map of surface displacement. StaMPS efficiently extracted the PS pixels on the unstable slopes in both areas and the time series 1D-LOS displacement map of PS pixels indicates that those areas in Nainital and Tehri region have measurement pixels with maximum displacement away from the satellite of the order of 22 mm/year and 17.6 mm/year respectively

Dwivedi, R.; Varshney, P.; Tiwari, A.; Singh, A. K.; Dikshit, O.

2014-11-01

155

KNb(1.75)V(0.25)PS(10).  

PubMed

The title compound, potassium diniobium vanadium phospho-rus deca-sulfide, KNb(1.75)V(0.25)PS(10), was obtained by reaction of the elements with a eutectic mixture of KCl/LiCl. It is isostructural with the quaternary KNb(2)PS(10), but the Nb sites are occupied by statistically disordered Nb (87.5%) and V (12.5%) atoms. The structure is composed of anionic (?) (1)[M(2)PS(10)](-) chains (M = Nb/V) separated from each other by K(+) ions. The chain is composed of [MS(8)] distorted bicapped trigonal prisms and [PS(4)] tetra-hedra. There are no inter-chain bonding inter-actions. The crystal used for the X-ray analysis was a racemic twin. PMID:21522232

Yu, Jaemin; Yun, Hoseop

2011-01-01

156

Serine-rich protein is a novel positive regulator for silicon accumulation in mangrove.  

PubMed

Silicon (Si) plays an important role in reducing plant susceptibility against a variety of different biotic and abiotic stresses; and also has an important regulatory role in soil to avoid heavy metal toxicity and providing suitable growing conditions for plants. A full-length cDNAs of 696bp of serine-rich protein was cloned from mangrove plant (Rhizophora apiculata) by amplification of cDNA ends from an expressed sequence tag homologous to groundnut (Arachis hypogaea), submitted to NCBI (KF211374). This serine-rich protein gene encodes a deduced protein of 223 amino acids. The transcript titre of the serine-rich protein was found to be strongly enriched in roots compared with the leaves of two month old mangrove plants and expression level of this serine-rich protein was found to be strongly induced when the mangrove seedlings were exposed to SiO2. Expression of the serine-rich protein transgenic was detected in transgenic Arabidopsis thaliana, where the amount of serine increased from 1.02 to 37.8mg/g. The same trend was also seen in Si content in the roots (14.3%) and leaves (7.4%) of the transgenic A. thaliana compared to the wild-type plants under Si treatment. The biological results demonstrated that the accumulation of the serine amino acid in the vegetative tissues of the transgenic plants enhanced their ability to absorb and accumulate more Si in the roots and leaves and suggests that the serine-rich protein gene has potential for use in genetic engineering of different stress tolerance characteristics. PMID:25479011

Sahebi, Mahbod; Hanafi, Mohamed M; Siti Nor Akmar, A; Rafii, Mohd Y; Azizi, Parisa; Idris, A S

2015-02-10

157

D-serine added to antipsychotics for the treatment of schizophrenia  

Microsoft Academic Search

Background: Hypofunction of N-methyl-D-aspartate (NMDA) subtype glutamate receptor has been implicated in the pathophysiology of schizophrenia. D-serine is a full agonist of the glycine site of NMDA receptor, an endogenous cotransmitter enriched in corticolimbic regions and distributed in parallel with NMDA receptor. Supplementation of D-serine may improve the symptoms of schizophrenia.Methods: Thirty-one Taiwanese schizophrenic patients enrolled in a 6-week double-blind,

Guochuan Tsai; Pinchen Yang; Li-Chen Chung; Nicholas Lange; Joseph T. Coyle

1998-01-01

158

Molecular Characterization of Membrane-Associated Soluble Serine Palmitoyltransferases from Sphingobacterium multivorum and Bdellovibrio stolpii  

Microsoft Academic Search

Serine palmitoyltransferase (SPT) is a key enzyme in sphingolipid biosynthesis and catalyzes the decar- boxylative condensation of L-serine and palmitoyl coenzyme A (CoA) to form 3-ketodihydrosphingosine (KDS). Eukaryotic SPTs comprise tightly membrane-associated heterodimers belonging to the pyridoxal 5-phosphate (PLP)-dependent -oxamine synthase family. Sphingomonas paucimobilis, a sphingolipid-containing bacterium, contains an abundant water-soluble homodimeric SPT of the same family (H. Ikushiro et

Hiroko Ikushiro; Mohammad Mainul Islam; Hiromasa Tojo; Hideyuki Hayashi

2007-01-01

159

Regulation of BAD phosphorylation at serine 112 by the Ras-mitogen-activated protein kinase pathway  

Microsoft Academic Search

The function of the pro-apoptotic molecule BAD is regulated by phosphorylation of two sites, serine-112 (Ser-112) and serine-136 (Ser-136). Phosphorylation at either site results in loss of the ability of BAD to heterodimerize with the survival proteins BCL-XL or BCL-2. Phosphorylated BAD binds to 14-3-3 and is sequestered in the cytoplasm. It has been shown that phosphorylation of BAD at

Xianjun Fang; Shuangxing Yu; Astrid Eder; Muling Mao; Robert C Bast; Douglas Boyd; Gordon B Mills

1999-01-01

160

The PS1 Science Mission - Status and Results  

NASA Astrophysics Data System (ADS)

PS1, the Pan-STARRS1 Telescope is in its last year of the PS1 Science Mission. Operations of the PS1 System include the Observatory, Telescope, 1.4 Gigapixel Camera, Image Processing Pipeline , PSPS relational database and reduced science product software servers. The PS1 Surveys include: (1) A 3pi Steradian Survey, (2) A Medium Deep survey of 10 PS1 footprints spaced around the sky; (3) A solar system survey optimized for Near Earth Objects, (4) a Stellar Transit Survey; and (5) a Deep Survey of M31. The PS1 3pi Survey has now covered the sky north of dec=-30 with 8 to 12 visits in five bands: g,r,i,z and y or over ~45 epochs per point on sky. The performance of the PS1 system, sky coverage, cadence, and data quality of the surveys will be presented as well as progress in reprocessing of the data taken to date and plans for serving the data to the public. A summary of science highlights will be included. The PS1 Science Consortium consists of The Institute for Astronomy at the University of Hawai'i in Manoa, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, the University of Durham, the University of Edinburgh, the Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Los Cumbres Observatory Global Telescope Network Incorporated, and the National Central University of Taiwan, NASA, and NSF.

Chambers, Kenneth C.

2013-06-01

161

A novel serine protease with caspase- and legumain-like activities from edible basidiomycete Flammulina velutipes.  

PubMed

A serine protease with caspase- and legumain-like activities from basidiocarps of the edible basidiomycete Flammulina velutipes was characterized. The protease was purified to near homogeneity by three steps of chromatography using acetyl-Tyr-Val-Ala-Asp-4-methylcoumaryl-7-amide (Ac-YVAD-MCA) as a substrate. The enzyme was termed FvSerP (F. velutipes serine protease). This enzyme activity was completely inhibited by the caspase-specific inhibitor, Ac-YVAD-CHO, as well as moderately inhibited by serine protease inhibitors. Based on the N-terminal sequence, the cDNA of FvSerP was identified. The deduced protease sequence was a peptide composed of 325 amino acids with a molecular mass of 34.5 kDa. The amino acid sequence of FvSerP showed similarity to neither caspases nor to the plant subtilisin-like serine protease with caspase-like activity called saspase. FvSerP shared identity to the functionally unknown genes from class of Agaricomycetes, with similarity to the peptidase S41 domain of a serine protease. It was thus concluded that this enzyme is likely a novel serine protease with caspase- and legumain-like activities belonging to the peptidase S41 family and distributed in the class Agaricomycetes. This enzyme possibly functions in autolysis, a type of programmed cell death that occurs in the later stages of development of basidiocarps with reference to their enzymatic functions. PMID:23537874

Iketani, Aya; Nakamura, Mayumi; Suzuki, Yuya; Awai, Koichiro; Shioi, Yuzo

2013-03-01

162

Thermodynamic characteristics of protolytic equilibria of L-serine in aqueous solutions  

NASA Astrophysics Data System (ADS)

The heat effects of the reaction of aqueous solution of L-serine with aqueous solutions of HNO3 and KOH were determined by calorimetry at temperatures of 288.15, 298.15, and 308.15 K, and ionic strength values of 0.2, 0.5, and 1.0 (background electrolyte, KNO3). Standard thermodynamic characteristics (?r H o, ?r G o, ?r S o, ? C {/p o}) of the acid-base reactions in aqueous solutions of L-serine were calculated. The effect of the concentration of background electrolyte and temperature on the heats of dissociation of amino acid was considered. The combustion energy of L-serine by bomb calorimetry in the medium of oxygen was determined. The standard combustion and formation enthalpies of crystalline L-serine were calculated. The heats of dissolution of crystalline L-serine in water and solutions of potassium hydroxide at 298.15 K were measured by direct calorimetry. The standard enthalpies of formation of L-serine and products of its dissociation in aqueous solution were calculated.

Kochergina, L. A.; Volkov, A. V.; Khokhlova, E. A.; Krutova, O. N.

2011-05-01

163

Joint PP and PS AVO inversion based on Zoeppritz equations  

NASA Astrophysics Data System (ADS)

Considering Zoeppritz equations, reflections of PP and PS are only the function of ratios of density and velocity. So the inversion results will be the same if the ratios are the same but values of density, velocities of P-wave and S-wave are different without strict constraint. This paper makes efforts to explore nonlinear simultaneous PP and PS inversion with expectation to reduce the ambiguity of AVO analysis by utilizing the redundancy of multi-component AVO measurements. Accurate estimation of ratio parameters depends on independence of input data. There are only two independent AVO attributes for PP reflectivity (i.e. intercept and gradient) and two for PS reflectivity (i.e. pseudo-intercept and pseudo-gradient or extreme amplitude), respectively. For individual PP and PS inversion, the values of least-squares objective function do not converge around a large neighborhood of chosen true model parameters. Fortunately for joint PP and PS inversion the values of the least-squares objective function show closed contours with single minima. Finally the power function fitting is used to provide a higher precision AVO attributes than traditional polynomial fitting. By using the four independent fitting attributes (two independent attributes for PP and PS respectively), the inversion of four ratio parameters (velocities and densities) would be estimated with less errors than that in traditional method.

Wei, Xiucheng; Chen, Tiansheng

2011-08-01

164

Structural Mechanisms of Inactivation in Scabies Mite Serine Protease Paralogues  

SciTech Connect

The scabies mite (Sarcoptes scabiei) is a parasite responsible for major morbidity in disadvantaged communities and immuno-compromised patients worldwide. In addition to the physical discomfort caused by the disease, scabies infestations facilitate infection by Streptococcal species via skin lesions, resulting in a high prevalence of rheumatic fever/heart disease in affected communities. The scabies mite produces 33 proteins that are closely related to those in the dust mite group 3 allergen and belong to the S1-like protease family (chymotrypsin-like). However, all but one of these molecules contain mutations in the conserved active-site catalytic triad that are predicted to render them catalytically inactive. These molecules are thus termed scabies mite inactivated protease paralogues (SMIPPs). The precise function of SMIPPs is unclear; however, it has been suggested that these proteins might function by binding and protecting target substrates from cleavage by host immune proteases, thus preventing the host from mounting an effective immune challenge. In order to begin to understand the structural basis for SMIPP function, we solved the crystal structures of SMIPP-S-I1 and SMIPP-S-D1 at 1.85 {angstrom} and 2.0 {angstrom} resolution, respectively. Both structures adopt the characteristic serine protease fold, albeit with large structural variations over much of the molecule. In both structures, mutations in the catalytic triad together with occlusion of the S1 subsite by a conserved Tyr200 residue is predicted to block substrate ingress. Accordingly, we show that both proteases lack catalytic function. Attempts to restore function (via site-directed mutagenesis of catalytic residues as well as Tyr200) were unsuccessful. Taken together, these data suggest that SMIPPs have lost the ability to bind substrates in a classical 'canonical' fashion, and instead have evolved alternative functions in the lifecycle of the scabies mite.

Fischer, Katja; Langendorf, Christopher G.; Irving, James A.; Reynolds, Simone; Willis, Charlene; Beckham, Simone; Law, Ruby H.P.; Yang, Sundy; Bashtannyk-Puhalovich, Tanya A.; McGowan, Sheena; Whisstock, James C.; Pike, Robert N.; Kemp, David J.; Buckle, Ashley M.; (Monash); (Queensland Inst. of Med. Rsrch.)

2009-08-07

165

Regulatory Functions of Serine-46-Phosphorylated HPr in Lactococcus lactis  

PubMed Central

In most low-G+C gram-positive bacteria, the phosphoryl carrier protein HPr of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) becomes phosphorylated at Ser-46. This ATP-dependent reaction is catalyzed by the bifunctional HPr kinase/P-Ser-HPr phosphatase. We found that serine-phosphorylated HPr (P-Ser-HPr) of Lactococcus lactis participates not only in carbon catabolite repression of an operon encoding a ?-glucoside-specific EII and a 6-P-?-glucosidase but also in inducer exclusion of the non-PTS carbohydrates maltose and ribose. In a wild-type strain, transport of these non-PTS carbohydrates is strongly inhibited by the presence of glucose, whereas in a ptsH1 mutant, in which Ser-46 of HPr is replaced with an alanine, glucose had lost its inhibitory effect. In vitro experiments carried out with L. lactis vesicles had suggested that P-Ser-HPr is also implicated in inducer expulsion of nonmetabolizable homologues of PTS sugars, such as methyl ?-d-thiogalactoside (TMG) and 2-deoxy-d-glucose (2-DG). In vivo experiments with the ptsH1 mutant established that P-Ser-HPr is not necessary for inducer expulsion. Glucose-activated 2-DG expulsion occurred at similar rates in wild-type and ptsH1 mutant strains, whereas TMG expulsion was slowed in the ptsH1 mutant. It therefore seems that P-Ser-HPr is not essential for inducer expulsion but that in certain cases it can play an indirect role in this regulatory process. PMID:11344147

Monedero, Vicente; Kuipers, Oscar P.; Jamet, Emmanuel; Deutscher, Josef

2001-01-01

166

Profiling the microRNA Expression in Human iPS and iPS-derived Retinal Pigment Epithelium  

PubMed Central

The purpose of this study is to characterize the microRNA (miRNA) expression profiles of induced pluripotent stem (iPS) cells and retinal pigment epithelium (RPE) derived from induced pluripotent stem cells (iPS-RPE). MiRNAs have been demonstrated to play critical roles in both maintaining pluripotency and facilitating differentiation. Gene expression networks accountable for maintenance and induction of pluripotency are linked and share components with those networks implicated in oncogenesis. Therefore, we hypothesize that miRNA expression profiling will distinguish iPS cells from their iPS-RPE progeny. To identify and analyze differentially expressed miRNAs, RPE was derived from iPS using a spontaneous differentiation method. MiRNA microarray analysis identified 155 probes that were statistically differentially expressed between iPS and iPS-RPE cells. Up-regulated miRNAs including miR-181c and miR-129–5p may play a role in promoting differentiation, while down-regulated miRNAs such as miR-367, miR-18b, and miR-20b are implicated in cell proliferation. Subsequent miRNA–target and network analysis revealed that these miRNAs are involved in cellular development, cell cycle progression, cell death, and survival. A systematic interrogation of temporal and spatial expression of iPS-RPE miRNAs and their associated target mRNAs will provide new insights into the molecular mechanisms of carcinogenesis, eye differentiation and development. PMID:25392691

Wang, Heuy-Ching; Greene, Whitney A; Kaini, Ramesh R; Shen-Gunther, Jane; Chen, Hung-I H; Cai, Hong; Wang, Yufeng

2014-01-01

167

Quantum chemical study of simple positronic systems using explicitly correlated Gaussian functions - PsH and PsLi+  

NASA Astrophysics Data System (ADS)

The electronic structure of positronium hydride has been studied using explicitly correlated Gaussian functions. The resulting energy constitutes new upper bound to the exact nonrelativistic energy of PsH within the Born-Oppenheimer approximation. The two photon annihilation rate was computed using the optimized wave function. Preliminary results for the positron bonded with the lithium atom indicate the stability of this system against the dissociation into Li+ cation and Ps atom.

Strasburger, K.; Chojnacki, H.

1998-02-01

168

Impact of mutations at different serine residues on the tyrosine kinase activity of the insulin receptor.  

PubMed

Insulin binding to its receptor activates a cascade of signaling events which are initiated by tyrosine autophosphorylation of the receptor and activation of the tyrosine kinase activity towards the insulin receptor substrates. In addition to phosphorylation at tyrosine residues a serine phosphorylation of the insulin receptor is observed. Neither the functional significance of serine phosphorylation of the receptor nor the location of relevant regulatory sites has been determined exactly so far. We studied potential functions of serine residues in human insulin receptor (HIR) with respect to its ability to undergo insulin stimulated autophosphorylation. Using site directed mutagenesis of HIR we exchanged serine to alanine at 13 different positions in the HIR beta-subunit. Sites were chosen according to the criteria of known serine phosphorylation sites (1023/25, 1293/94, 1308/09), conserved positions in hIR, hIGF-1 receptor, hIRR, and dIR (962, 994, 1037, 1055, 1074/78, 1168, 1177/78/82, 1202, 1263, 1267). All HIR mutants were expressed in HEK 293 cells and basal and insulin stimulated autophosphorylation were determined. We found that the exchange of serine to alanine at position 994 and at position 1023/25 increased insulin stimulated receptor autophosphorylation significantly (147% +/- 12% and 129% +/- 6% of control, p < 0.01, n = 7), while all other exchanges did not significantly alter insulin stimulated HIR autophosphorylation. The data suggest that the serine residues at position 994 as well as 1023/25 might be part of inhibitory domains of the insulin receptor. PMID:9345301

Strack, V; Stoyanov, B; Bossenmaier, B; Mosthaf, L; Kellerer, M; Häring, H U

1997-10-01

169

Antimicrobial activity of a honeybee (Apis cerana) venom Kazal-type serine protease inhibitor.  

PubMed

Insect-derived Kazal-type serine protease inhibitors exhibit thrombin, elastase, plasmin, proteinase K, or subtilisin A inhibition activity, but so far, no functional roles for bee-derived Kazal-type serine protease inhibitors have been identified. In this study, a bee (Apis cerana) venom Kazal-type serine protease inhibitor (AcKTSPI) that acts as a microbial serine protease inhibitor was identified. AcKTSPI contained a single Kazal domain that displayed six conserved cysteine residues and a P1 threonine residue. AcKTSPI was expressed in the venom gland and was present as a 10-kDa peptide in bee venom. Recombinant AcKTSPI Kazal domain (AcKTSPI-Kd) expressed in baculovirus-infected insect cells demonstrated inhibitory activity against subtilisin A (Ki 67.03 nM) and proteinase K (Ki 91.53 nM), but not against ?-chymotrypsin or trypsin, which implies a role for AcKTSPI as a microbial serine protease inhibitor. However, AcKTSPI-Kd exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or elastase. Additionally, AcKTSPI-Kd bound directly to Bacillus subtilis, Bacillus thuringiensis, Beauveria bassiana, and Fusarium graminearum but not to Escherichia coli. Consistent with these findings, AcKTSPI-Kd showed antibacterial activity against Gram-positive bacteria and antifungal activity against both plant-pathogenic and entomopathogenic fungi. These findings constitute molecular evidence that AcKTSPI acts as an inhibitor of microbial serine proteases. This paper provides a novel view of the antimicrobial functions of a bee venom Kazal-type serine protease inhibitor. PMID:24076031

Kim, Bo Yeon; Lee, Kwang Sik; Zou, Feng Ming; Wan, Hu; Choi, Yong Soo; Yoon, Hyung Joo; Kwon, Hyung Wook; Je, Yeon Ho; Jin, Byung Rae

2013-12-15

170

Cs0.49NbPS6  

PubMed Central

The quaternary thio­phosphate, Cs0.49NbPS6, caesium hexa­thio­niobiophosphate(V), has been synthesized by the reactive halide flux method. The title compound is isotypic with Rb0.46TaPS6 and is made up of a bicapped trigonal–biprismatic [Nb2S12] unit and a tetra­hedral [PS4] group. The [Nb2S12] units linked by the [PS4] tetra­hedra form infinite chains, yielding a three-dimensional network with rather large van der Waals gaps along the c axis in which the disordered Cs+ ions reside. The electrons released by the Cs atoms are transferred to the pairwise niobium metal site and there are substantial inter­metallic Nb—Nb bonding inter­actions. This leads to a significant decrease of the inter­metallic distance in the title compound compared to that in TaPS6. The classical charge balance of the title compound may be represented as [Cs+]0.49[Nb4.51+][P5+][S2?]4[S2 2?]. PMID:21522512

Lee, Eunsil; Lee, Yonghee; Yun, Hoseop

2011-01-01

171

Mobility Measurements of Freely-Standing Cyclic PS Films  

NASA Astrophysics Data System (ADS)

Reductions in the glass transition temperature Tg have been observed for thin, freely-standing films of linear polystyrene (PS) (Forrest et al.), PRE 61, R53 (2000); Dalnoki-Veress et al., PRE, in press., which indicates increased segmental mobility. Despite topological differences between cyclic and linear PS, their bulk rheological properties are similar, apart from a factor of approximately two difference in zero shear viscosity, plateau modulus, and steady state recoverable compliance (McKenna et al.), Macromolecules 20, 489 (1987); 22, 1834 (1989).. We investigate the mobility of freely-standing films of cyclic and linear PS chains with molecular weight Mw ~ 200k and thicknesses 20 nm < h < 150 nm. Using ellipsometry, we have measured the temperature dependence of h and the index of refraction n of the films. In all cyclic PS films, we observe irreversible changes in h for temperatures T > 90^circC. For the thinnest cyclic PS films, irreversible changes in n are also observed for T > 90^circC. We relate the results of these measurements to the determination of T_g, chain diffusion and anisotropy within the films. Chain diffusion was further studied using optical microscopy to measure hole growth in the films as a function of h and T.

Murray, Chris A.; Dutcher, John R.; McKenna, Gregory B.

2001-03-01

172

Characterization of crosslinked polystyrene(PS) beads in SBR matrix  

SciTech Connect

Monodisperse sized crosslinked polystyrene(PS) beads were prepared by a reaction of semibatch emulsion polymerization with styrene monomer, divinylbenzene(DVB) crosslinking agent and potassium persulfate(K{sub 2}S{sub 2}O{sub 9}) initiator in the absence of emulsifier. The glass transition temperature(T{sub g}) and the mean diameter of the beads were increased from 100{degrees}C to 135{degrees}C and from 402 nm to 532 nm, respectively, for an incorporation of 2 to 10 mol% DVB. Crosslinking density was also linearly increased with DVB content. SEM microphotographs of SBR composite filled with various contents of PS beads revealed that PS beads are relatively well dispersed without changing the spherical shape of the beads in all range of compositions. In stress-strain analysis, elongation at break and tensile strength of SBR composite were increased with the bead content. Applicability of the PS beads as a filler in SBR matrix is tested by plotting Mooney-Rivlin or Guth-Smallwood equations. However, mechanical properties of the composite with the beads were not so excellent as those of the composite with carbon black. Crosslinked PS beads are still tentative as a white color reinforcing filler on SBR matrix.

Cha, Yoon-Jong; Choe, Soonja [Inha Univ. (Korea, Republic of)

1995-12-01

173

Assessment of dentin remineralization with PS-OCT  

NASA Astrophysics Data System (ADS)

Previous studies have demonstrated that polarization sensitive optical coherence tomography (PS-OCT) can be used to image natural root caries lesions, measure non-destructively the severity of dentin demineralization and determine the efficacy of intervention with anti-caries agents including fluoride and lasers. The objective of this study was to determine if PS-OCT could be used to nondestructively measure the formation of a layer of remineralized dentin on the surface of dentin lesions after exposure to a remineralization solution. In this study images of artificial dentin lesions on extracted human teeth were acquired using PS-OCT after exposure to an artificial demineralizing solution at pH 4.9 for six days and after subsequent exposure to a remineralizing solution at pH 7.0 for 20 days. Polarized light microscopy and microradiography were used to examine histological thin sections from the samples for comparison. PS-OCT successfully measured the formation of a layer of increased mineral content near the lesion surface. PLM and TMR corroborated those results. This study demonstrates the potential use of PS-OCT for the nondestructive measurement of the remineralization of dentin surfaces.

Manesh, Saman K.; Darling, Cynthia L.; Fried, Daniel

2009-02-01

174

Enhanced function annotations for Drosophila serine proteases: A case study for systematic annotation of multi-member gene families  

Microsoft Academic Search

Systematicallyannotatingfunctionofenzymesthatbelongtolargeproteinfamiliesencodedinasingleeukaryoticgenomeisaverychallengingtask. We carried out such an exercise to annotate function for serine-protease family of the trypsin fold in Drosophila melanogaster, with an emphasis on annotating serine-protease homologues (SPHs) that may have lost their catalytic function. Our approach involves data mining and data integration to providefunction annotations for 190Drosophilagene products containing serine-protease-like domains,ofwhich 35areSPHs. Thiswas accomplished by analysis of structure-function relationships,

Parantu K. Shah; Lokesh P. Tripathi; Lars Juhl Jensen; Murad Gahnim; Christopher Mason; Eileen E. Furlong; Veronica Rodrigues; Kevin P. White; Peer Bork; R. Sowdhamini

2007-01-01

175

Breast Cancer-Associated pS2 Protein: Synthesis and Secretion by Normal Stomach Mucosa  

Microsoft Academic Search

The human pS2 gene is specifically expressed under estrogen transcriptional control in a subclass of estrogen receptor-containing human breast cancer cells. The pS2 gene encodes an 84-amino acid protein that is secreted after signal peptide cleavage. The distribution of pS2 protein in normal human tissues was studied with antibodies to pS2; pS2 was specifically expressed and secreted by mucosa cells

M. C. Rio; J. P. Bellocq; J. Y. Daniel; C. Tomasetto; R. Lathe; M. P. Chenard; A. Batzenschlager; P. Chambon

1988-01-01

176

Bioinformatics analysis of the serine and glycine pathway in cancer cells  

PubMed Central

Serine and glycine are amino acids that provide the essential precursors for the synthesis of proteins, nucleic acids and lipids. Employing 3 subsequent enzymes, phosphoglycerate dehydrogenase (PHGDH), phosphoserine phosphatase (PSPH), phosphoserine aminotransferase 1 (PSAT1), 3-phosphoglycerate from glycolysis can be converted in serine, which in turn can by converted in glycine by serine methyl transferase (SHMT). Besides proving precursors for macromolecules, serine/glycine biosynthesis is also required for the maintenance of cellular redox state. Therefore, this metabolic pathway has a pivotal role in proliferating cells, including cancer cells. In the last few years an emerging literature provides genetic and functional evidences that hyperactivation of serine/glycine biosynthetic pathway drives tumorigenesis. Here, we extend these observations performing a bioinformatics analysis using public cancer datasets. Our analysis highlighted the relevance of PHGDH and SHMT2 expression as prognostic factor for breast cancer, revealing a substantial ability of these enzymes to predict patient survival outcome. However analyzing patient datasets of lung cancer our analysis reveled that some other enzymes of the pathways, rather than PHGDH, might be associated to prognosis. Although these observations require further investigations they might suggest a selective requirement of some enzymes in specific cancer types, recommending more cautions in the development of novel translational opportunities and biomarker identification of human cancers. PMID:25436979

Morello, Maria; Minieri, Marilena; Melino, Gerry; Amelio, Ivano

2014-01-01

177

Cell-type specific mechanisms of D-serine uptake and release in the brain  

PubMed Central

Accumulating evidence during the last decade established that D-serine is a key signaling molecule utilized by neurons and astroglia in the mammalian central nervous system. D-serine is increasingly appreciated as the main physiological endogenous coagonist for synaptic NMDA receptors at central excitatory synapses; it is mandatory for long-term changes in synaptic strength, memory, learning, and social interactions. Alterations in the extracellular levels of D-serine leading to disrupted cell-cell signaling are a trademark of many chronic or acute neurological (i.e., Alzheimer disease, epilepsy, stroke) and psychiatric (i.e., schizophrenia) disorders, and are associated with addictive behavior (i.e., cocaine addiction). Indeed, fine tuning of the extracellular levels of D-serine, achieved by various molecular machineries and signaling pathways, is necessary for maintenance of accurate NMDA receptor functions. Here, we review the experimental data supporting the notion that astroglia and neurons use different pathways to regulate levels of extracellular D-serine. PMID:24910611

Martineau, Magalie; Parpura, Vladimir; Mothet, Jean-Pierre

2014-01-01

178

Neuropathogenesis of HIV-1-associated neurocognitive disorders: a possible involvement of D-serine  

PubMed Central

A unique feature of N-methyl-D-aspartate receptors (NMDARs) that distinguishes them from other ionic receptors is that their activation requires more than one agonist to bind simultaneously to distinct binding sites on the receptor. D-serine, a co-agonist binding to the glycine site of NMDARs, has been implicated in several NMDAR-dependent physiological processes, and altered D-serine levels under certain pathophysiological conditions contribute to neural dysfunction via NMDARs in the central nervous system. Entry of HIV-1 in the brain causes neuronal injury leading to cognitive, behavioral and motor impairments known as HIV-associated neurocognitive disorders (HAND). As HIV-1 does not infect neurons, neuronal injury is believed to be primarily mediated by an indirect mechanism,that is, HIV-1-infected and/or immune-activated macrophages and microglial cells release soluble molecules leading to neuronal injury or death. Among the soluble factors is D-serine. In this article we try to address recent progresses on the role D-serine might play in the pathogenesis of neurodegenerative disorders with a particular emphasis of the involvement of D-serine in HIV-1-associated neurotoxicity. PMID:24044033

Xia, Jianxun; Xiong, Huangui

2013-01-01

179

The Cutting Edge: Membrane Anchored Serine Protease Activities in the Pericellular Microenvironment  

PubMed Central

Synopsis The serine proteases of the trypsin-like (S1) family play critical roles in many key biological processes including digestion, blood coagulation, and immunity. Recent studies have identified members of this family which contain amino- or carboxy-terminal domains that serve to tether the serine protease catalytic domain directly at the plasma membrane. These membrane anchored serine proteases are proving to be key components of the cell machinery for activation of precursor molecules in the pericellular microenvironment, playing vital functions in the maintenance of homeostasis. Substrates activated by membrane anchored serine proteases include peptide hormones, growth and differentiation factors, receptors, enzymes, adhesion molecules and viral coat proteins. In addition, new insights into our understanding of the physiological functions of these proteases and their involvement in human pathology have come from animal models and patient studies. This review discusses emerging evidence for the diversity of this fascinating group of membrane serine proteases as potent modifiers of the pericellular microenvironment through proteolytic processing of diverse substrates. We also discuss the functional consequences of the activities of these proteases on mammalian physiology and disease. PMID:20507279

Antalis, Toni M.; Buzza, Marguerite S.; Hodge, Kathryn M.; Hooper, John D.; Netzel-Arnett, Sarah

2013-01-01

180

Application of Infrared Multiphoton Dissociation Spectroscopy for the Study of Chiral Recognition in Protonated Serine Clusters  

NASA Astrophysics Data System (ADS)

Serine is an amino acid which has long been known to form "magic-number" ionic clusters, serine octamer [Ser_8 + H]^+. It has been shown that serine octamers exhibit strong preference for homochirality, but its structure is still unclear. We have used infrared multiphoton dissociation (IRMPD) spectroscopic technique coupled with a Fourier transform ion cyclotron (FRICR) mass spectrometer to investigate the structures of protonated serin octamer and dimer as well as the chiral recognition in these clusters. With the use of ICR cell, the ions can be stored for a sufficient time so that measurements of IRMPD spectra become possible with a CW OPO laser in the 3000-4000 cm-1 region. As an aid to interpret the observed spectra, molecular structures and vibrational frequencies of the octamer and dimer have been predicted by using the B3LYP/6-311++G** calculations. Differences in chiral selectivity between the serine octamer and dimer will be discussed. S. C. Nanita and R. G. Cooks Angew. Chem. Int. Ed. 45(554), 2006.

Sunahori, Fumie X.; Yang, Guochun; Kitova, Elena N.; Klassen, John S.; Xu, Yunjie

2010-06-01

181

The N-methyl D-aspartate receptor glycine site and D-serine metabolism: an evolutionary perspective.  

PubMed Central

The N-methyl D-aspartate (NMDA) type of glutamate receptor requires two distinct agonists to operate. Glycine is assumed to be the endogenous ligand for the NMDA receptor glycine site, but this notion has been challenged by the discovery of high levels of endogenous d-serine in the mammalian forebrain. I have outlined an evolutionary framework for the appearance of a glycine site in animals and the metabolic events leading to high levels of D-serine in brain. Sequence alignments of the glycine-binding regions, along with the scant experimental data available, suggest that the properties of invertebrate NMDA receptor glycine sites are probably different from those in vertebrates. The synthesis of D-serine in brain is due to a pyridoxal-5'-phosphate (B(6))-requiring serine racemase in glia. Although it remains unknown when serine racemase first evolved, data concerning the evolution of B(6) enzymes, along with the known occurrences of serine racemases in animals, point to D-serine synthesis arising around the divergence time of arthropods. D-Serine catabolism occurs via the ancient peroxisomal enzyme d-amino acid oxidase (DAO), whose ontogenetic expression in the hindbrain of mammals is delayed until the postnatal period and absent from the forebrain. The phylogeny of D-serine metabolism has relevance to our understanding of brain ontogeny, schizophrenia and neurotransmitter dynamics. PMID:15306409

Schell, Michael J

2004-01-01

182

Application of Infrared Multiphoton Dissociation Spectroscopy for the Study of Chiral Recognition in the Protonated Serine Clusters: Part II  

NASA Astrophysics Data System (ADS)

Serine is an amino acid which has long been known to form the magic-number serine octamer [Ser_8 + H]^+. It has been shown that the serine octamer exhibits strong preference for homochirality. Although a few possible structures for the homochiral serine octamer have been proposed, no definite conclusion has so far been drawn. Last year at this conference, we reported on the study of the protonated serine octamer and dimer as well as the chiral recognition in these clusters using infrared multiphoton dissociation (IRMPD) spectroscopic technique coupled with a Fourier transform ion cyclotron (FTICR) mass spectrometer. Here we present our latest results on the search for the infrared signatures of chiral recognition in the serine octamer and the dimer using a mixture of the deuterated 2,3,3-d_3-L-serine and normal D-serine solution. Using the isotopic labeled species, we could isolate the heterochiral species and obtain their IRMPD spectra which can be directly compared with those of the homochiral species. As an aid to interpret the observed spectra, molecular structures and vibrational frequencies of both homochiral and heterochiral octamer and dimer have been predicted by ab initio calculations. New insights into the hitherto undetermined structure of the serine octamer will be discussed. S. C. Nanita and R. G. Cooks Angew. Chem. Int. Ed. 45, (554), 2006.

Sunahori, Fumie X.; Kitova, Elena N.; Klassen, John S.; Xu, Yunjie; Yang, Guochun

2011-06-01

183

A modified EOM method for PS-wave migration  

NASA Astrophysics Data System (ADS)

A modified EOM method is developed for PS-wave migration based on the equivalent offset migration (EOM) for P-waves. This gives better imaging quality than the previous EOM methods by reducing errors from the discretisation of equivalent offsets and suppressing noise from the co-location of source-receiver. An equivalent PS-wave velocity is also introduced. Processing real 2-dimensional 3-component seismic data shows that the method can produce a better migrated image than the conventional common conversion point (CCP) method.

Wang, Yun; Wang, Wei; Yin, Junjie

2012-05-01

184

SEA and strategy formation theories: From three Ps to five Ps  

SciTech Connect

A transition to environmentally sustainable societies should involve a significant and comprehensive - strategic - change. Much of the promise of SEA is associated precisely with its perceived capacity to facilitate such a strategic transformation by influencing selected 'strategic decisions'. This paper examines the potential effectiveness and limitations of such an approach in light of contemporary organizational strategy theories. Most of these theories separate 'strategies' from 'decisions' and also transcend the notion of strategies as formal plans, policies and programs (PPPs). Instead, they consider strategies as 'five Ps', adding 'Position', 'Perspective', 'Pattern' and 'Ploy' to the 'Plan'. Lessons from organizational strategy formation give rise to the following challenges for SEA theory and practice: 1.How to assess and influence informal as well as formal aspects of strategic initiatives? 2.How to extend SEA 'beyond decisions' to address 'emergent strategies' where strategic action is not necessarily preceded by a decision? 3.How to ensure that knowledge provided as a result of SEA is strategically relevant and communicated to key players in strategy formation? 4.How to deal with an uncontrollable and unpredictable environment in which strategic initiatives unfold? 5.How to recognize those situations when SEA can have most strategic influence? This paper takes a step towards examining these challenges by exploring the intellectual history of SEA in light of the main strategy formation theories and by identifying directions in which the SEA discourse may be further enhanced to meet these five challenges.

Cherp, Aleh [Central European University, Hungary and International Institute for Industrial Environmental Economics, Lund University (Sweden)], E-mail: aleh.cherp@iiiee.lu.se; Watt, Alan [Central European University (Hungary)], E-mail: watta@ceu.hu; Vinichenko, Vadim [Ecoline Environmental Assessment Center (Russian Federation)], E-mail: vadim@vinichenko.org

2007-10-15

185

Serine biosynthesis by photorespiratory and non-photorespiratory pathways: an interesting interplay with unknown regulatory networks.  

PubMed

Photorespiration is a primary metabolic pathway, which, given its energy costs, has often been viewed as a wasteful process. Despite having reached the consensus that one important function of photorespiration is the removal of toxic metabolite intermediates, other possible functions have emerged, and others could well emerge in the future. As a primary metabolic pathway, photorespiration interacts with other routes; however the nature of these interactions is not well known. One of these interacting pathways could be the biosynthesis of serine, since this amino acid is synthesised through photorespiratory and non-photorespiratory routes. At present, the exact contribution of each route to serine supply in different tissues and organs, their biological significance and how pathways are integrated and/or regulated remain unknown. Here, we review the non-photorespiratory serine biosynthetic pathways, their interactions with the photorespiratory pathway, their putative role in plants and their biotechnological interest. PMID:23199004

Ros, R; Cascales-Miñana, B; Segura, J; Anoman, A D; Toujani, W; Flores-Tornero, M; Rosa-Tellez, S; Muñoz-Bertomeu, J

2013-07-01

186

Conservation of sequence and function in fertilization of the cortical granule serine protease in echinoderms.  

PubMed

Conservation of the cortical granule serine protease during fertilization in echinoderms was tested both functionally in sea stars, and computationally throughout the echinoderm phylum. We find that the inhibitor of serine protease (soybean trypsin inhibitor) effectively blocks proper transition of the sea star fertilization envelope into a protective sperm repellent, whereas inhibitors of the other main types of proteases had no effect. Scanning the transcriptomes of 15 different echinoderm ovaries revealed sequences of high conservation to the originally identified sea urchin cortical serine protease, CGSP1. These conserved sequences contained the catalytic triad necessary for enzymatic activity, and the tandemly repeated LDLr-like repeats. We conclude that the protease involved in the slow block to polyspermy is an essential and conserved element of fertilization in echinoderms, and may provide an important reagent for identification and testing of the cell surface proteins in eggs necessary for sperm binding. PMID:24878526

Oulhen, Nathalie; Xu, Dongdong; Wessel, Gary M

2014-08-01

187

Modelling of tumour--host coexistence In vitro in the presence of serine protease inhibitors.  

PubMed

The activities of cell surface serine proteases are markedly enhanced in malignant tumours. Proteolytic degradation of the extracellular matrix and basal membrane of normal cells is an important event for tumour cell growth and invasion. Two well-known broad-spectrum inhibitors of serine protease, Foy-305 and Ono-3403, were evaluated for their ability to affect the growth rate and survival of MCF7 breast cancer cells co-cultured with MRC5 lung fibroblasts as feeder cells in the absence of serum. Flow cytometry and differential staining demonstrated that in the mixed culture, the rate of tumor growth was dependent upon the presence of the feeder MRC5 lung fibroblasts and could be obviated by the additional presence of the inhibitors of serine proteases. PMID:19779105

Engi, Helga; Gyémánt, Nóra; Ohkoshi, Motohiro; Amaral, Leonard; Molnár, Joseph

2009-01-01

188

Microfluidic analysis of serine levels using seryl-tRNA synthetase coupled with spectrophotometric detection.  

PubMed

The measurement of amino acid content is useful for the diagnosis of several types of diseases, including cancer and diabetes. In this study, a microfluidic method for the analysis of serine using enzymatic reactions coupled with spectrophotometric detection was developed. The assay system has some advantages in the analytical field, such as the ability to detect small amounts of analyte and reaction solution and a rapid and efficient reaction. For the specific detection of serine, seryl-tRNA synthetase was coupled with the generation of hydrogen peroxide, which was then detected by the Trinder reagent spectrophotometric method. Seryl- and other aminoacyl-tRNA synthetases are involved in the biosynthesis of peptides and proteins in the human body and should allow precise recognition of the corresponding amino acids. This approach provided selective quantitation of up to 250 ?M serine in 100 mM Tris-HCl buffer (pH 8.0) in a semiautomatic system. PMID:25190303

Kugimiya, Akimitsu; Matsuzaki, Emi

2014-12-01

189

Macluralisin--a serine proteinase from fruits of Maclura pomifera (Raf.) Schneid.  

PubMed

A serine proteinase was isolated from fruits of Maclura pomifera (Raf.) Schneid. by affinity chromatography on bacitracin-containing sorbents and gel-filtration. The enzyme, named macluralisin, is a glycoprotein with a molecular mass of 65 kDa; its protein moiety corresponds to a molecular mass of 50 kDa. The substrate specificity of macluralisin towards synthetic peptides and insulin B-chain is similar to that of cucumisin, a subtilisin-like proteinase from melon fruit. The enzyme is completely inhibited by diisopropylfluorophosphate. Its amino-acid composition resembles that of a serine proteinase isolated from the Cucurbitaceae. The N-terminal sequence has 33% of its residues identical to those of the sequence of fungal subtilisin-like proteinase K. Hence, Maclura pomifera serine proteinase belongs to the subtilisin family, which seems to be broadly distributed in the plant kingdom. PMID:7767235

Rudenskaya, G N; Bogdanova, E A; Revina, L P; Golovkin, B N; Stepanov, V M

1995-01-01

190

On the roles of the alanine and serine in the ?-sheet structure of fibroin.  

PubMed

In its silk II form, fibroin is almost exclusively formed from layers of ?-sheets, rich in glycine, alanine and serine. Reported here are computational results on fibroin models at semi-empirical, DFT levels of theory and molecular dynamics (MD) for (Gly)10, (Gly-Ala)5 and (Gly-Ser)5 decapeptides. While alanine and serine introduce steric repulsions, the alanine side-chain adds to the rigidity of the sheet, allowing it to maintain a properly pleated structure even in a single ?-sheet, and thus avoiding two alternative conformations which would interfere with the formation of the multi-layer pleated-sheet structure. The role of the serine is proposed to involve modulation of the hydrophobicity in order to construct the supramolecular assembly as opposed to random precipitation due to hydrophobicity. PMID:25484116

Carrascoza Mayen, Juan Francisco; Lupan, Alexandru; Cosar, Ciprian; Kun, Attila-Zsolt; Silaghi-Dumitrescu, Radu

2014-11-15

191

Dynamic regulation of d-serine release in the vertebrate retina.  

PubMed

The purpose of this study was to investigate the functional properties of NMDA receptor coagonist release and to specifically evaluate whether light-evoked release mechanisms contribute to the availability of the coagonist D-serine. Two different methods were involved in our approach, including i) whole-cell recordings from identified retinal ganglion cells in the tiger salamander were used to study light adaptation with positive and negative contrast stimuli over a range of ± 1 log unit against a steady background illumination and ii) we studied the mechanisms for intensity encoding to a range of light intensities covering 6 log10 units. This latter study employed extracellular recordings of the proximal negative field potential (PNFP), pharmacologically manipulated to generate a pure NMDA mediated response. For the adaptation study we examined the light-evoked responses under control conditions, followed by light stimuli presented in the presence of D-serine, followed by light stimulation in the presence of dichlorokynurenic acid to block the coagonist site of NMDA receptors. For the brightness encoding studies we examined the action of D-serine on each intensity used in the study and then applied the enzyme D-serine deaminase (DsdA) to remove significant levels of D-serine. These studies provided new insights into the mechanisms that regulate coagonist availability in the vertebrate retina. Our results strongly support the idea that light-evoked coagonist release, a major component of which is D-serine, is needed to provide the full range of coagonist availability for optimal activation of NMDA receptors. This article is protected by copyright. All rights reserved. PMID:25480802

Gustafson, Eric G; Stevens, Eric S; Miller, Robert F

2014-12-01

192

Long term potentiation depends on release of D-serine from astrocytes  

PubMed Central

Long-term potentiation (LTP) of synaptic transmission provides an experimental model for studying mechanisms of memory1. The classical form of LTP relies on N-methyl-D-aspartate receptors (NMDARs), and it has emerged that astroglia can regulate their activation through Ca2+-dependent release of the NMDAR co-agonist D-serine2-4. Release of D-serine from glia enables LTP in cultures5 and explains a correlation between glial coverage of synapses and LTP in the supraoptic nucleus4. However, Ca2+ elevations in astroglia can also release other signalling molecules, most prominently glutamate6-8, Adenosine-5?-triphosphate9, and Tumor-Necrosis-Factor-?10,11 whereas neurons themselves can synthesise and supply D-serine12,13. Furthermore, loading an astrocyte with exogenous Ca2+ buffers does not suppress LTP in hippocampal area CA114-16, and the physiological relevance of experiments in cultures or strong exogenous stimuli applied to astrocytes has been questioned17,18. The involvement of glia in LTP induction thus remains controversial. Here we show that clamping internal Ca2+ in individual CA1 astrocytes blocks LTP induction at nearby excitatory synapses by reducing the occupancy of the NMDAR co-agonist sites. This LTP blockade can be reversed by exogenous D-serine or glycine whereas depletion of D-serine or disruption of exocytosis in an individual astrocyte blocks local LTP. We thus demonstrate that Ca2+-dependent release of D-serine from an astrocyte controls NMDAR-dependent plasticity in many thousands of excitatory synapses occurring nearby. PMID:20075918

Henneberger, Christian; Papouin, Thomas; Oliet, Stéphane H. R.; Rusakov, Dmitri A.

2009-01-01

193

Remodeling natural products: chemistry and serine hydrolase activity of a rocaglate-derived ?-lactone.  

PubMed

Flavaglines are a class of natural products with potent insecticidal and anticancer activities. ?-Lactones are a privileged structural motif found in both therapeutic agents and chemical probes. Herein, we report the synthesis, unexpected light-driven di-epimerization, and activity-based protein profiling of a novel rocaglate-derived ?-lactone. In addition to in vitro inhibition of the serine hydrolases ABHD10 and ACOT1/2, the most potent ?-lactone enantiomer was also found to inhibit these enzymes, as well as the serine peptidases CTSA and SCPEP1, in PC3 cells. PMID:24447064

Lajkiewicz, Neil J; Cognetta, Armand B; Niphakis, Micah J; Cravatt, Benjamin F; Porco, John A

2014-02-12

194

Remodeling Natural Products: Chemistry and Serine Hydrolase Activity of a Rocaglate-Derived ?-Lactone  

PubMed Central

Flavaglines are a class of natural products with potent insecticidal and anticancer activities. ?-Lactones are a privileged structural motif found in both therapeutic agents and chemical probes. Herein, we report the synthesis, unexpected light-driven di-epimerization, and activity-based protein profiling of a novel rocaglate-derived ?-lactone. In addition to in vitro inhibition of the serine hydrolases ABHD10 and ACOT1/2, the most potent ?-lactone enantiomer was also found to inhibit these enzymes, as well as the serine peptidases CTSA and SCPEP1, in PC3 cells. PMID:24447064

2015-01-01

195

A para-nitrophenol phosphonate probe labels distinct serine hydrolases of Arabidopsis.  

PubMed

Activity-based protein profiling represents a powerful methodology to probe the activity state of enzymes under various physiological conditions. Here we present the development of a para-nitrophenol phosphonate activity-based probe with structural similarities to the potent agrochemical paraoxon. We demonstrate that this probes labels distinct serine hydrolases with the carboxylesterase CXE12 as the predominant target in Arabidopsis thaliana. The designed probe features a distinct labeling pattern and therefore represents a promising chemical tool to investigate physiological roles of selected serine hydrolases such as CXE12 in plant biology. PMID:21763150

Nickel, Sabrina; Kaschani, Farnusch; Colby, Tom; van der Hoorn, Renier A L; Kaiser, Markus

2012-01-15

196

Novel serine phosphorylation of pp60c-src in intact cells after tumor promoter treatment.  

PubMed Central

Treatment of normal cells with the tumor promoters 12-O-tetradecanoylphorbol-13-acetate and mezerein results in increased phosphorylation of pp60c-src. Two-dimensional tryptic phosphopeptide analysis of partial V8 protease fragments indicated that this phosphorylation takes place on a serine residue which lies within the amino-terminal 18 kilodaltons of pp60c-src and represents the major phosphorylation site following tumor promoter treatment. Untreated cells exhibited a low but detectable level of phosphorylation at this serine residue. The significance of these results with respect to the phosphoregulation of pp60c-src as well as tumor promotion is discussed. Images PMID:2431272

Gentry, L E; Chaffin, K E; Shoyab, M; Purchio, A F

1986-01-01

197

Contribution of Gelatinase, Serine Protease, and fsr to the Pathogenesis of Enterococcus faecalis Endophthalmitis  

PubMed Central

Gelatinase and serine protease were found to contribute in concert to pathogenesis in a rabbit model of endophthalmitis. However, a mutant defective in the fsr regulator was observed to be more attenuated than a mutant rendered defective in the expression of gelatinase and serine protease as the result of a polar transposon insertion into the former. This increased attenuation suggests that there are possible additional pleiotropic effects of the defect in fsr on expression of traits contributing to the pathogenesis of enterococcal infection. PMID:15155673

Engelbert, Michael; Mylonakis, Eleftherios; Ausubel, Frederick M.; Calderwood, Stephen B.; Gilmore, Michael S.

2004-01-01

198

Region-specific metabolic alterations in the brain of the APP/PS1 transgenic mice of Alzheimer's disease.  

PubMed

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide, but its etiology is still not completely understood. The identification of underlying pathological mechanisms is becoming increasingly important for the discovery of biomarkers and therapies, for which metabolomics presents a great potential. In this work, we studied metabolic alterations in different brain regions of the APP/PS1 mice by using a high-throughput metabolomic approach based on the combination of gas chromatography-mass spectrometry and ultra-high performance liquid chromatography-mass spectrometry. Multivariate statistics showed that metabolomic perturbations are widespread, affecting mainly the hippocampus and the cortex, but are also present in regions not primarily associated with AD such as the striatum, cerebellum and olfactory bulbs. Multiple metabolic pathways could be linked to the development of AD-type disorders in this mouse model, including abnormal purine metabolism, bioenergetic failures, dyshomeostasis of amino acids and disturbances in membrane lipids, among others. Interestingly, region-specific alterations were observed for some of the potential markers identified, associated with abnormal fatty acid composition of phospholipids and sphingomyelins, or differential regulation of neurotransmitter amino acids (e.g. glutamate, glycine, serine, N-acetyl-aspartate), not previously described to our knowledge. Therefore, these findings could provide a new insight into brain pathology in Alzheimer's disease. PMID:25281826

González-Domínguez, Raúl; García-Barrera, Tamara; Vitorica, Javier; Gómez-Ariza, José Luis

2014-12-01

199

Data-Acquisition Board For IBM PS/2 Computer  

NASA Technical Reports Server (NTRS)

Circuit board containing microprocessors designed to control acquisition of data by IBM PS/2 computer. Plugged into one of 16-bit slots on mother board of computer. Controls transfer of data from as many as 48 discrete channels to Micro Channel Interface. With expansion of software, board recognizes and filters specified kinds of signal patterns, possibly to detect errors.

Hoang, Phuong-Dung T.

1990-01-01

200

Solvent annealing of Micropatterned PS-b-PEO copolymer films  

NASA Astrophysics Data System (ADS)

Solvent annealing of block copolymer thin films have been known as an effective way to control both orientation of microdomains with respect to the surface and their registration into a well ordered periodic lattice structure. We have recently demonstrated hierarchically ordered microdomains in a thin poly(styrene-b-ethylene oxide)(PS-b-PEO) film combined with microcontact printing. The solvent annealing gave rise to well ordered spherical PEO microdomains in large area by the confined dewetting of thin PS-b-PEO films which had been micropatterned on chemically modified surface during solvent annealing. In this presentation, we intentionally prepare a micropatterned dewet film of PS-b-PEO by spincoating a block copolymer solution on a topographic PDMS pre-pattern. Convex lens shaped spherical caps of PS-b-PEO individually located on each PDMS mesa were successfully transferred to a Si substrate by a conventional transfer printing technique. We investigate the effect of solvent on not only film wettability but also formation of hierarchical nanostructures.

Kim, Tae Hee; Acharya, Himadri; Joeng, Hee June; Park, Cheolmin

2009-03-01

201

Boiling treatment of ABS and PS plastics for flotation separation.  

PubMed

A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile-butadiene-styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling. PMID:24602834

Wang, Chong-qing; Wang, Hui; Wu, Bao-xin; Liu, Qun

2014-07-01

202

Petroleum Technology (AS) Curriculum Guide Student Name: PS#  

E-print Network

Petroleum Technology (AS) ­ Curriculum Guide Student Name: PS# GENERAL EDUCATION REQUIREMENTS ENG Introduction to Petroleum Industry PET 0102 Environment and Safety PET 0103 Introduction to Petroleum Geology PET 0201 Petroleum & Natural Gas Chemistry PET 0203 Oil & Gas Gathering & Transportation PET 0204 Well

Jiang, Huiqiang

203

Framing Retention for Institutional Improvement: A 4 Ps Framework  

ERIC Educational Resources Information Center

A 4 Ps framework for student retention strategy is a construct for reframing the retention discussion in a way that enables institutional improvement by challenging some conventional wisdom and prevailing perspectives that have characterized retention strategy for years. It opens new possibilities for action and improvement by suggesting that…

Kalsbeek, David H.

2013-01-01

204

BioMaPS: A Roadmap for Success  

ERIC Educational Resources Information Center

The manuscript outlines the impact that our National Science Foundation Interdisciplinary Training for Undergraduates in Biological and Mathematical Sciences program, BioMaPS, has had on the students and faculty at Murray State University. This interdisciplinary program teams mathematics and biology undergraduate students with mathematics and…

McCarthy, Maeve L.; Fister, K. Renee

2010-01-01

205

Competitive Activity-Based Protein Profiling Identifies Aza-?-Lactams as a Versatile Chemotype for Serine Hydrolase Inhibition  

PubMed Central

Serine hydrolases are one of the largest and most diverse enzyme classes in Nature. Most serine hydrolases lack selective inhibitors, which are needed for assigning functions to these enzymes. We recently discovered a set of aza-?-lactams (ABLs) that act as potent and selective inhibitors of the mammalian serine hydrolase protein-phosphatase methylesterase-1 (PME-1). The ABLs inactivate PME-1 by covalent acylation of the enzyme’s serine nucleophile, suggesting that they could offer a general scaffold for serine hydrolase inhibitor discovery. Here, we have tested this hypothesis by screening ABLs more broadly against cell and tissue proteomes by competitive activity-based protein profiling (ABPP), leading to the discovery of lead inhibitors for several serine hydrolases, including the uncharacterized enzyme alpha, beta-hydrolase-10 (ABHD10). ABPP-guided medicinal chemistry yielded a compound ABL303 that potently (IC50 value ~ 30 nM) and selectively inactivated ABHD10 in vitro and in living cells. A comparison of optimized inhibitors for PME-1 and ABHD10 indicates that modest structural changes that alter steric bulk can tailor the ABL to selectively react with distinct, sequence-unrelated serine hydrolases. Our findings, taken together, designate the ABL as a versatile reactive group for creating first-in-class serine hydrolase inhibitors. PMID:22400490

Zuhl, Andrea M.; Mohr, Justin T.; Bachovchin, Daniel A.; Niessen, Sherry; Hsu, Ku-Lung; Berlin, Jacob M.; Dochnahl, Maximilian; López-Alberca, María P.; Fu, Gregory C.; Cravatt, Benjamin F.

2012-01-01

206

Evaluation of the Proteolytic Activity of Factor D Accumulated as an Active Serine Protease in Patients with Chronic Renal Failure  

Microsoft Academic Search

Complement factor D, a complement system serine protease, circulating in vivo as its active form, accumulates in patients with chronic renal failure. The pathophysiological role of this active protease in these patients was examined by studies on activities of excess factor D on 10 synthetic peptide substrates for some usual serine proteases. The most sensitive of these substrates to factor

Reiko Inagi; Toshio Miyata; Osamu Oda; Kenji Maedd; Kozo Inoue

1994-01-01

207

Expression and location of phospho-Artemis (Serine516) in hair follicles during induced growth of mouse hair.  

PubMed

Artemis has been implicated in having a role in NHEJ, and it is also a multifunctional protein. Previous studies have found Omenn syndrome-like phenotype due to Artemis mutations and associated with alopecia. As Artemis phosphorylation in its c-terminus including Serine516 is prerequisite for the Artemis endonuclease reaction, we postulate that Artemis (Serine516) may be expressed in hair follicle and relate to hair cycling. In this study, hair growth in C57BL/6 mice was induced by plucking the telogen hair on the back. Expression of Artemis (Serine516) in hair follicles during the hair growth cycle was evaluated by immunofluorescence using cryosections and a specific polyclonal anti-Artemis (Serine516) immunoglobulin G (IgG) antibody. It was detected in germ cells, cap, and club hair adjoining the epidermis in telogen. In anagen II, intense staining for Artemis (Serine516) was found in the whole interfollicular epidermis, and in strand keratinocytes. In anagen IV, intense staining for Artemis (Serine516) was detected in basal cells and upper of outer root sheath (ORS) and inner root sheath (IRS). But only upper ORS and lower medulla were stained positive in anagen VI. Upper ORS and lower cortex were positively stained with Artemis (Serine516) in catagen. Based on the phenomenon that the expression of Artemis (Serine516) in mid-anagen and mature anagen was stronger than that in telogen and catagen, we suggest it may take roles in induced growth of mouse hair. PMID:22476261

Wu, Xian-Jie; Zhu, Jian-Wei; Liu, Hai; Lu, Zhong-Fa; Zheng, Min

2012-05-01

208

A serine elastase inhibitor reduces inflammation and fibrosis and preserves cardiac function after experimentally-induced murine myocarditis  

Microsoft Academic Search

In viral myocarditis, inflammation and destruction of cardiac myocytes leads to fibrosis, causing progressive impairment in cardiac function. Here we show the etiologic importance of serine elastase activity in the pathophysiology of acute viral myocarditis and the therapeutic efficacy of an elastase inhibitor. In DBA\\/2 mice inoculated with the encephalomyocarditis virus, a more than 150% increase in myocardial serine elastase

Jong K. Lee; Syed H. E. Zaidi; Peter Liu; Fayez Dawood; Alexander Y. L. Cheah; Wen-Hu Wen; Yuriko Saiki; Marlene Rabinovitch

1998-01-01

209

Roles of Serine Accumulation and Catabolism in the Colonization of the Murine Urinary Tract by Escherichia coli CFT073?  

PubMed Central

A d-serine deaminase (DsdA) mutant of uropathogenic Escherichia coli strain CFT073 has a hypercolonization phenotype in a murine model of urinary tract infection (UTI) due to increased virulence gene expression by an unknown mechanism (B. J. Haugen et al., Infect. Immun. 75:278-289, 2007). DsdC is a d-serine-dependent activator of dsdXA transcription. DsdC may regulate the virulence genes responsible for hypercolonization. The loss of DsdA leads to increased intracellular accumulation of d-serine. In this study we show that deletion of the genes encoding l-serine deaminases SdaA and SdaB resulted in a mutant that accumulates higher intracellular levels of l-serine than CFT073. CFT073 sdaA sdaB has a mild competitive colonization defect whereas a CFT073 dsdA sdaA sdaB triple mutant shows a greater loss in competitive colonization ability. Thus, the inability to generate serine-specific catabolic products does not result in hypercolonization and the ability to catabolize serine represents a positive physiological trait during murine UTI. CFT073 dsdC and CFT073 dsdC dsdA mutants continue to outcompete the wild type in the UTI model. These results confirm that loss of DsdA activity results in the hypercolonization phenotype and that DsdC does not play a direct role in the elevated-colonization phenotype. Interestingly, a CFT073 dsdA mutant with deletions of d-serine transporter genes dsdX and cycA shows wild-type colonization levels of the bladder but is attenuated for kidney colonization. Thus, d-serine acts as a signal for hypercolonization and virulence gene expression by CFT073 dsdA, whereas overall catabolism of serine represents a positive Escherichia coli fitness trait during UTI. PMID:17785472

Anfora, Andrew T.; Haugen, Brian J.; Roesch, Paula; Redford, Peter; Welch, Rodney A.

2007-01-01

210

Effects of Second Messengers on Serine\\/Threonine Protein Phosphatases in Insulin-Secreting Cells  

Microsoft Academic Search

Reversible protein phosphorylation is an important and versatile mechanism by which cells transduce external signals into biological responses. Cellular levels of protein phosphorylation are determined by the balanced actions of both protein kinases and protein phosphatases (PPases). Compared with protein kinases, however, serine\\/threonine PPases have received less attention. In the present study, the effects of certain insulin secretagogues and intracellular

Åke Sjöholm; Per-Olof Berggren; Richard E. Honkanen

2001-01-01

211

Reciprocal coupling of coagulation and innate immunity via neutrophil serine proteases  

Microsoft Academic Search

Blood neutrophils provide the first line of defense against pathogens but have also been implicated in thrombotic processes. This dual function of neutrophils could reflect an evolutionarily conserved association between blood coagulation and antimicrobial defense, although the molecular determinants and in vivo significance of this association remain unclear. Here we show that major microbicidal effectors of neutrophils, the serine proteases

Steffen Massberg; Lenka Grahl; Marie-Luise von Bruehl; Davit Manukyan; Susanne Pfeiler; Christian Goosmann; Volker Brinkmann; Michael Lorenz; Kiril Bidzhekov; Avinash B Khandagale; Ildiko Konrad; Elisabeth Kennerknecht; Katja Reges; Stefan Holdenrieder; Siegmund Braun; Christoph Reinhardt; Michael Spannagl; Klaus T Preissner; Bernd Engelmann

2010-01-01

212

FLR-4, a Novel Serine\\/Threonine Protein Kinase, Regulates Defecation Rhythm in Caenorhabditis elegans  

Microsoft Academic Search

The defecation behavior of the nematode Caenorhabditis elegans is controlled by a 45-s ultradian rhythm. An essential component of the clock that regulates the rhythm is the inositol trisphosphate receptor in the intestine, but other components remain to be discovered. Here, we show that the flr-4 gene, whose mutants exhibit very short defecation cycle periods, encodes a novel serine\\/threonine protein

Masaya Take-uchi; Yuri Kobayashi; Koutarou D. Kimura; Takeshi Ishihara; Isao Katsura

2005-01-01

213

Nucleotide sequence and expression of a cDNA encoding rabbit liver cytosolic serine hydroxymethyltransferase.  

PubMed Central

A rabbit liver cDNA library in phage lambda gt10 was screened using a portion of the coding sequences for rabbit cytosolic serine hydroxymethyltransferase (amino acids 244-420) that had been amplified by PCR, with total rabbit liver RNA as a template. A clone of 2.3 kb (pUS1203) was isolated and the nucleotide sequence showed that it contained an open reading frame of 1452 bp, which coded for serine hydroxymethyltransferase and was flanked by 155 bp at the 5' end and 653 bp at the 3' end. The full-length cDNA was cloned into an expression vector and transfected into COS-1 cells. Serine hydroxymethyltransferase activity was increased by 33% in the transfected cells and a new protein band of the appropriate size was seen by SDS/PAGE analysis of proteins extracted from transfected cells. The protein sequence for rabbit cytosolic serine hydroxymethyltransferase derived from the cDNA nucleotide sequence was compared with three other derived or known prokaryotic and eukaryotic sequences. An overall sequence similarity of 34% was noted between all four sequences, whereas the similarity between the rabbit cytosolic and mitochondrial isoforms was 62%. Images Fig. 1. Fig. 2. Fig. 4. PMID:1381582

Byrne, P C; Sanders, P G; Snell, K

1992-01-01

214

Cloning, expression and activity analysis of a novel fibrinolytic serine protease from Arenicola cristata  

NASA Astrophysics Data System (ADS)

The full-length cDNA of a protease gene from a marine annelid Arenicola cristata was amplified through rapid amplification of cDNA ends technique and sequenced. The size of the cDNA was 936 bp in length, including an open reading frame encoding a polypeptide of 270 amino acid residues. The deduced amino acid sequnce consisted of pro- and mature sequences. The protease belonged to the serine protease family because it contained the highly conserved sequence GDSGGP. This protease was novel as it showed a low amino acid sequence similarity (< 40%) to other serine proteases. The gene encoding the active form of A. cristata serine protease was cloned and expressed in E. coli. Purified recombinant protease in a supernatant could dissolve an artificial fibrin plate with plasminogen-rich fibrin, whereas the plasminogen-free fibrin showed no clear zone caused by hydrolysis. This result suggested that the recombinant protease showed an indirect fibrinolytic activity of dissolving fibrin, and was probably a plasminogen activator. A rat model with venous thrombosis was established to demonstrate that the recombinant protease could also hydrolyze blood clot in vivo. Therefore, this recombinant protease may be used as a thrombolytic agent for thrombosis treatment. To our knowledge, this study is the first of reporting the fibrinolytic serine protease gene in A. cristata.

Zhao, Chunling; Ju, Jiyu

2014-10-01

215

The Prostate 62:1^13 (2005) Substrates ofthe Prostate-Specific Serine Protease  

E-print Network

The Prostate 62:1^13 (2005) Substrates ofthe Prostate-Specific Serine Protease Prostase/KLK4. Prostase/KLK4 is a member of the human kallikrein (KLK) gene family that is expressed in prostate with potential roles mediating normal prostate physiology or neoplastic growth including KLK3/ PSA, parathyroid

Craik, Charles S.

216

Proteasomal serine hydrolases are up-regulated by and required for influenza virus infection.  

PubMed

Interactions between viruses and their host cells are important determinants of virus replication and of immune responses to the virus. However, these interactions and resulting consequences of these interactions remain poorly defined. Numerous recent quantitative proteomic approaches have measured host proteins affected by virus infection. Here, we used activity-based protein profiling (ABPP) to measure functional alterations in host serine hydrolases after influenza A virus infection of Madin-Darby canine kidney and human A549 lung cells. We identified 62 serine proteases. We then combined the ABPP approach with stable isotope labeling to directly measure how serine hydrolase activities were affected by virus infection. Differentially regulated SHs mapped into a few key cellular pathway systems, most notably the proteasomal system. The specific serine protease inhibitors Aprotinin and Pefablock and specific proteasomal inhibitors Bortezomib and MG132 significantly inhibited influenza virus growth. Some inhibitors also down-regulated activities of several proteasomal proteins, including PSMA1, PSMA2, and PMSB3. Genetic knockdown of PMSA2 also attenuated influenza virus replication. These findings further our understanding of enzymatic cellular processes affected by influenza virus and may be beneficial in the search for additional antiviral therapeutic targets. PMID:24669782

Shahiduzzaman, Md; Ezatti, Peyman; Xin, Gang; Coombs, Kevin M

2014-05-01

217

Mast cells limit extracellular levels of IL-13 via a serglycin proteoglycan-serine protease axis.  

PubMed

Mast cell (MC) granules contain large amounts of proteases of the chymase, tryptase and carboxypeptidase A (MC-CPA) type that are stored in complex with serglycin,a proteoglycan with heparin side chains. Hence, serglycinprotease complexes are released upon MC degranulation and may influence local inflammation. Here we explored the possibility that a serglycin-protease axis may regulate levels of IL-13, a cytokine involved in allergic asthma. Indeed, we found that wild-type MCs efficiently degraded exogenous or endogenously produced IL-13 upon degranulation,whereas serglycin ?/? MCs completely lacked this ability.Moreover, MC-mediated IL-13 degradation was blocked both by a serine protease inhibitor and by a heparin antagonist,which suggests that IL-13 degradation is catalyzed by serglycin-dependent serine proteases and that optimal IL-13 degradation is dependent on both the serglycin and the protease component of the serglycin-protease complex.Moreover, IL-13 degradation was abrogated in MC-CPA ?/?MC cultures, but was normal in cultures of MCs with an inactivating mutation of MC-CPA, which suggests that the IL-13-degrading serine proteases rely on MC-CPA protein.Together, our data implicate a serglycin-serine protease axis in the regulation of extracellular levels of IL-13. Reduction of IL-13 levels through this mechanism possibly can provide a protective function in the context of allergic inflammation. PMID:23667909

Waern, Ida; Karlsson, Iulia; Thorpe, Michael; Schlenner, Susan M; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Åbrink, Magnus; Hellman, Lars; Pejler, Gunnar; Wernersson, Sara

2012-12-01

218

POLYMORPHISMS IN CYTOPLASMIC SERINE HYDROXYMETHYLTRANSFERASE AND METHYLENETETRAHYDROFOLATE REDUCTASE AFFECT THE RISK OF CARDIOVASCULAR DISEASE IN MEN  

Technology Transfer Automated Retrieval System (TEKTRAN)

Genetic variation in folate-regulating enzymes contributes to the risk of cardiovascular disease (CVD). The cytoplasmic serine hydroxymethyltransferase (cSHMT) enzyme is proposed to regulate a key metabolic intersection in folate metabolism. We hypothesized that a variant in cSHMT (cSHMT 1420CT) aff...

219

Related Arabidopsis serine carboxypeptidase-like sinapoylglucose acyltransferases display distinct but overlapping substrate specificities  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Arabidopsis genome encodes fifty-one proteins annotated as serine carboxypeptidase-like (SCPL) enzymes. Nineteen of these SCPL proteins are highly similar to one another, and represent a clade that appears to be unique to plants. Two of these proteins have been characterized to date: sinapoylgl...

220

Nuclear localization and in vivo dynamics of a plant-specic serine/arginine-rich protein  

E-print Network

Nuclear localization and in vivo dynamics of a plant-speci®c serine/arginine-rich protein Gul Shad Aliy , Maxim Golovkiny and Anireddy S. N. Reddy� Department of Biology and Program in Cell August 2003; accepted 16 September 2003. � For correspondence (fax 1 970 491 0649; e-mail reddy

Reddy, A.S.N

221

Inhibition of Amyloid ?-Protein Production in Neural Cells by the Serine Protease Inhibitor AEBSF  

Microsoft Academic Search

Cerebral deposition of amyloid ? protein (A?) is an early and critical feature of Alzheimer's disease. A? production requires the proteolytic release of A? from the ?-amyloid precursor protein (?APP). Thus, inhibition of A? release is a prime therapeutic goal. Here, we show that the broad spectrum, irreversible serine protease inhibitor, AEBSF, inhibits the constitutive production of A? in five

M Citron; T. S Diehl; A Capell; C Haass; D. B Teplow; D. J Selkoe

1996-01-01

222

Microarray analysis reveals strategies of Tribolium castaneum larvae to compensate for cysteine and serine protease inhibitors  

Technology Transfer Automated Retrieval System (TEKTRAN)

Microarrays containing Tribolium castaneum whole-genome sequences were developed to study the transcriptome response of T. castaneum larvae to dietary protease inhibitors. In larvae fed diets containing 0.1% of the cysteine protease inhibitor E-64 alone or in combination with 5.0% of the serine pro...

223

Chirality recognition of the protonated serine dimer and octamer by infrared multiphoton dissociation spectroscopy.  

PubMed

Infrared multiphoton dissociation (IRMPD) spectroscopy has been used to record IR signatures of chirality recognition in the protonated serine dimer and octamer in the 3200-3800 cm(-1) region. This is the first IRMPD study to investigate the heterochiral biomolecular system by utilizing the isotope-labelled species. Noticeable differences in the homo- versus heterochiral IRMPD spectra have been obtained experimentally for both the dimer and octamer. Different dissociation patterns have been noted not only between the homo- and heterochiral octamers, but also between the two -OH stretching vibrational bands of the same chirality species. Systematic theoretical searches have been carried out to identify the most stable conformers of both the homo- and heterochiral protonated serine dimer and octamer. The final geometry optimization and harmonic vibrational calculations have been performed at the MP2/6-311++G(d,p) level for the homo- and heterochiral protonated serine dimer and at the B3LYP/6-31G(d) level for the homo- and heterochiral protonated serine octamer. For the homo- and heterochiral dimer, good agreement between the experimental and theoretical spectra has been achieved and the major conformers have been identified. For the homo- and heterochiral octamer, the main IR features observed have been satisfactorily reproduced theoretically and the dominant conformers identified. More than one main conformer has been identified for the homochiral octamer. This conclusion has been further supported by the analysis of the wavelength specific dissociation products. PMID:23247298

Sunahori, Fumie X; Yang, Guochun; Kitova, Elena N; Klassen, John S; Xu, Yunjie

2013-02-14

224

Expectation values of the e{sup +}PsH system  

SciTech Connect

Close to converged energies and expectation values for e{sup +}PsH are computed using a ground-state wave function consisting of 1500 explicitly correlated Gaussians. The best estimate of the e{sup +}PsH{sup {infinity}} energy was -0.810 254 hartrees, which has a binding energy of 0.021 057 hartrees against dissociation into e{sup +}+PsH. The 2{gamma} annihilation rate was 2.7508x10{sup 9} s{sup -1}. Binding energies and annihilation rates are also given for the different finite-mass variants of e{sup +}PsH. Comparisons between expectation values for e{sup +}PsH and PsH provide compelling evidence that the e{sup +}PsH ground state can be regarded as consisting of a weakly bound positron orbiting the PsH ground state.

Zhang, J.-Y.; Mitroy, J. [Faculty of Technology, Charles Darwin University, Darwin, Northern Territory 0909 (Australia); ARC Center for Anti-Matter Studies, Faculty of Technology, Charles Darwin University, Darwin, Northern Territory 0909 (Australia)

2007-07-15

225

Conformations of serine in aqueous solutions as revealed by vibrational circular dichroism.  

PubMed

Vibrational circular dichroism (VCD) spectroscopy is utilized to reveal the detailed conformational distributions of the dominant serine species in aqueous solutions under three representative pH conditions of 1.0, 5.7, and 13.0, together with vibrational absorption (VA) spectroscopy, density functional theory (DFT), and molecular dynamics simulation. The experimental VA and VCD spectra of serine in H(2)O and D(2)O in the fingerprint region under three pH values are obtained. DFT calculations at the B3LYP/6-311++G(d,p) level are carried out for the protonated, zwitterionic, and deprotonated serine species. The lowest-energy conformers of all three species are identified and their corresponding VA and VCD spectra simulated. A comparison between the gas-phase simulations and the experimental VA and VCD spectra suggests that one or two of the most stable conformers of each species contribute predominantly to the observed data, although some discrepancies are noted. To account for the solvent effects, both the polarizable continuum model and the explicit solvation model are considered. Hydrogen-bonded protonated, zwitterionic, and deprotonated serine-(water)(6) clusters are constructed based on radial distribution function analyses and molecular dynamics snapshots. Geometry optimization and VA and VCD simulations are performed for these clusters at the B3LYP/6-311++G(d,p) level. Inclusion of the explicit water molecules is found to improve the agreement between theory and experiment noticeably in all three cases, thus enabling conclusive conformational distribution analyses of serine in aqueous solutions directly. PMID:22334359

Zhu, Peiyang; Yang, Guochun; Poopari, Mohammad Reza; Bie, Zhi; Xu, Yunjie

2012-04-10

226

Functional and structural characterization of Vibrio cholerae extracellular serine protease B, VesB.  

PubMed

The chymotrypsin subfamily A of serine proteases consists primarily of eukaryotic proteases, including only a few proteases of bacterial origin. VesB, a newly identified serine protease that is secreted by the type II secretion system in Vibrio cholerae, belongs to this subfamily. VesB is likely produced as a zymogen because sequence alignment with trypsinogen identified a putative cleavage site for activation and a catalytic triad, His-Asp-Ser. Using synthetic peptides, VesB efficiently cleaved a trypsin substrate, but not chymotrypsin and elastase substrates. The reversible serine protease inhibitor, benzamidine, inhibited VesB and served as an immobilized ligand for VesB affinity purification, further indicating its relationship with trypsin-like enzymes. Consistent with this family of serine proteases, N-terminal sequencing implied that the propeptide is removed in the secreted form of VesB. Separate mutagenesis of the activation site and catalytic serine rendered VesB inactive, confirming the importance of these features for activity, but not for secretion. Similar to trypsin but, in contrast to thrombin and other coagulation factors, Na(+) did not stimulate the activity of VesB, despite containing the Tyr(250) signature. The crystal structure of catalytically inactive pro-VesB revealed that the protease domain is structurally similar to trypsinogen. The C-terminal domain of VesB was found to adopt an immunoglobulin (Ig)-fold that is structurally homologous to Ig-folds of other extracellular Vibrio proteins. Possible roles of the Ig-fold domain in stability, substrate specificity, cell surface association, and type II secretion of VesB, the first bacterial multidomain trypsin-like protease with known structure, are discussed. PMID:24459146

Gadwal, Shilpa; Korotkov, Konstantin V; Delarosa, Jaclyn R; Hol, Wim G J; Sandkvist, Maria

2014-03-21

227

Communicating Knowing through Communities of Practice: Exploring Internal Communicative Processes and Differences among CoPs  

ERIC Educational Resources Information Center

Knowing is an enacted, communicated process that is difficult to observe, let alone manage, in organizations. Communities of practice (CoPs) offer a productive solution for improving knowledge and knowledge management, but the communicative processes that enact CoPs have not been explored, leaving CoPs as an organizational black box. This research…

Iverson, Joel O.; McPhee, Robert D.

2008-01-01

228

7 CFR 1753.7 - Plans and specifications (P&S).  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Plans and specifications (P&S). 1753.7 Section 1753.7 Agriculture ...PROCEDURES General § 1753.7 Plans and specifications (P&S). (a) The P&S consist of an RUS contract form, the...

2010-01-01

229

7 CFR 1753.47 - Plans and specifications (P&S).  

...2014-01-01 false Plans and specifications (P&S). 1753.47 Section 1753.47 Agriculture... § 1753.47 Plans and specifications (P&S). (a) General. (1) Prior to the preparation of P&S for the construction project:...

2014-01-01

230

7 CFR 1753.47 - Plans and specifications (P&S).  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Plans and specifications (P&S). 1753.47 Section 1753.47 Agriculture... § 1753.47 Plans and specifications (P&S). (a) General. (1) Prior to the preparation of P&S for the construction project:...

2010-01-01

231

7 CFR 1753.26 - Plans and specifications (P&S).  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Plans and specifications (P&S). 1753.26 Section 1753.26... § 1753.26 Plans and specifications (P&S). (a) For headquarters and commercial...only, the borrower shall prepare preliminary P&S showing the floor plan and...

2011-01-01

232

7 CFR 1753.7 - Plans and specifications (P&S).  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Plans and specifications (P&S). 1753.7 Section 1753.7 Agriculture ...PROCEDURES General § 1753.7 Plans and specifications (P&S). (a) The P&S consist of an RUS contract form, the...

2013-01-01

233

7 CFR 1753.7 - Plans and specifications (P&S).  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 false Plans and specifications (P&S). 1753.7 Section 1753.7 Agriculture ...PROCEDURES General § 1753.7 Plans and specifications (P&S). (a) The P&S consist of an RUS contract form, the...

2011-01-01

234

7 CFR 1753.7 - Plans and specifications (P&S).  

... 2014-01-01 false Plans and specifications (P&S). 1753.7 Section 1753.7 Agriculture ...PROCEDURES General § 1753.7 Plans and specifications (P&S). (a) The P&S consist of an RUS contract form, the...

2014-01-01

235

7 CFR 1753.26 - Plans and specifications (P&S).  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Plans and specifications (P&S). 1753.26 Section 1753.26... § 1753.26 Plans and specifications (P&S). (a) For headquarters and commercial...only, the borrower shall prepare preliminary P&S showing the floor plan and...

2013-01-01

236

7 CFR 1753.26 - Plans and specifications (P&S).  

...2014-01-01 false Plans and specifications (P&S). 1753.26 Section 1753.26... § 1753.26 Plans and specifications (P&S). (a) For headquarters and commercial...only, the borrower shall prepare preliminary P&S showing the floor plan and...

2014-01-01

237

7 CFR 1753.47 - Plans and specifications (P&S).  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Plans and specifications (P&S). 1753.47 Section 1753.47 Agriculture... § 1753.47 Plans and specifications (P&S). (a) General. (1) Prior to the preparation of P&S for the construction project:...

2011-01-01

238

7 CFR 1753.47 - Plans and specifications (P&S).  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Plans and specifications (P&S). 1753.47 Section 1753.47 Agriculture... § 1753.47 Plans and specifications (P&S). (a) General. (1) Prior to the preparation of P&S for the construction project:...

2013-01-01

239

7 CFR 1753.7 - Plans and specifications (P&S).  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Plans and specifications (P&S). 1753.7 Section 1753.7 Agriculture ...PROCEDURES General § 1753.7 Plans and specifications (P&S). (a) The P&S consist of an RUS contract form, the...

2012-01-01

240

7 CFR 1753.26 - Plans and specifications (P&S).  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Plans and specifications (P&S). 1753.26 Section 1753.26... § 1753.26 Plans and specifications (P&S). (a) For headquarters and commercial...only, the borrower shall prepare preliminary P&S showing the floor plan and...

2012-01-01

241

7 CFR 1753.47 - Plans and specifications (P&S).  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Plans and specifications (P&S). 1753.47 Section 1753.47 Agriculture... § 1753.47 Plans and specifications (P&S). (a) General. (1) Prior to the preparation of P&S for the construction project:...

2012-01-01

242

DP-PS: A safety program for DP operations  

SciTech Connect

As Petrobras develops its deepwater projects, more and more DP units are used on different applications like drilling, completion, intervention and pipeline handling. The increasing complexity of the operations has been considered in a program entitled DP-PS (Safety Program For Dynamic Positioning Operations) in order to minimize the risks of failures which could lead to serious accidents on subsea and surface installations as well as to the DP vessels. This paper briefly presents the DP-PS, consisting of a group of related projects considering different aspects of DP operations, like: Vessels Incidents Databank, Emergency Disconnection procedures, Risk Comparison, DGPS (Differential Global Positioning System) application, Well Control Equipment and Standard procedures, Testing Programs and Guidelines for DP Operations. The high number of DP contractors operating in Brazil and the atmosphere of cooperation in which the program has been developed was a key factor for its success. As a result, the number of DP incidents has remarkably decreased.

Cordeiro, A.; Paschoalin, R.; Fartes, E. [Petrobras, Rio de Janeiro (Brazil)

1996-12-31

243

Experimental performance of SPD/PS detector prototypes  

E-print Network

We describe current status of the development of Scintillator Pad Detector and PreShower detector prototypes for the LHCb experiment at CEftIV. SPD/PS consists of two identical layers of scintillator pads with a lead converter in between. The pads are read-out by single WLS fibres coiled in a groove in the scintillator body. Experimental results obtained with several prototypes during 1999-2000 years are described.

Filippov, S; Guschin, E; Laptev, S V; Postoev, V E

2000-01-01

244

Study of Derivative of DPQ with PS Polymer Matrix  

NASA Astrophysics Data System (ADS)

A blue light-emitting material, Trichloro substituted diphenyl quinoline (Trichloro-DPQ) has been synthesized by Friedlander condensation at 140 °C. The structural and photoluminescence properties of Trichloro-DPQ were studied. The PL spectra of thin films of the Trichloro-DPQ embedded in PS matrix were investigated at different weight % concentrations like 10, 5, 1 and 0.1 wt %. The luminescent properties of these materials become thus of interest for both fundamental and applied research.

Raut, S. B.; Dhoble, S. J.; Atram, R. G.

2011-10-01

245

Screening of serine protease inhibitors with antimicrobial activity using iron oxide nanoparticles functionalized with dextran conjugated trypsin and in silico analyses of bacterial serine protease inhibition.  

PubMed

Plants produce a variety of proteins and peptides which are involved in their defense against pathogens. Serine protease inhibitors are a well-established class of inhibitors correlated with plant defense. Increased levels of protease inhibitors delay cell damage and expand the cell's life-span. Recently, the rapid emergence of antibiotic-resistant microbial pathogens has prompted immense interest in purifying novel antimicrobial proteins or peptides from plant sources. Usually, the purification of protease inhibitors is accomplished by salt-extraction, ultrafiltration and affinity chromatography. Here, we developed a novel approach based on iron oxide nanoparticles conjugated to dextran functionalized with trypsin beads that accelerate the quick screening and purification of antimicrobial peptides with serine protease inhibitor activity. The method described here also works for screening other inhibitors using particular protein kinases, and it is therefore a novel tool for use as the leading method in the development of novel antimicrobial agents with protease inhibitory activity. Finally, and no less important, molecular modelling and dynamics studies of a homologous inhibitor studied here with Escherichia coli trypsin and chymotrypsin are provided in order to shed some light on inhibitor-enzyme interactions. PMID:24294628

Mandal, Santi M; Porto, William F; De, Debasis; Phule, Ajit; Korpole, Suresh; Ghosh, Ananta K; Roy, Sanat K; Franco, Octavio L

2014-01-21

246

Characterization of the usage of the serine metabolic network in human cancer  

PubMed Central

The serine, glycine, one carbon (SGOC) metabolic network is implicated in cancer pathogenesis but its general functions are unknown. We carried out a computational reconstruction of the SGOC network and then characterized its expression across thousands of cancer tissues. Pathways including methylation and redox metabolism exhibited heterogeneous expression indicating a strong context dependency of their usage in tumors. From an analysis of coexpression, simultaneous up- or down-regulation of nucleotide synthesis, NADPH and glutathione synthesis was found to be a common occurrence in all cancers. Finally, we developed a method to trace the metabolic fate of serine using stable isotopes, high-resolution mass spectrometry and a mathematical model. Although the expression of single genes didn’t appear indicative of flux, the collective expression of several genes in a given pathway allowed for successful flux prediction. Together these findings identify expansive and heterogeneous functions for the SGOC metabolic network in human cancer. PMID:25456139

Mehrmohamadi, Mahya; Liu, Xiaojing; Shestov, Alexander A; Locasale, Jason W

2015-01-01

247

Function and regulation of serine/threonine phosphatases in the healthy and diseased heart.  

PubMed

Protein phosphorylation is a major control mechanism of a wide range of physiological processes and plays an important role in cardiac pathophysiology. Serine/threonine protein phosphatases control the dephosphorylation of a variety of cardiac proteins, thereby fine-tuning cardiac electrophysiology and function. Specificity of protein phosphatases type-1 and type-2A is achieved by multiprotein complexes that target the catalytic subunits to specific subcellular domains. Here, we describe the composition, regulation and target substrates of serine/threonine phosphatases in the heart. In addition, we provide an overview of pharmacological tools and genetic models to study the role of cardiac phosphatases. Finally, we review the role of protein phosphatases in the diseased heart, particularly in ventricular arrhythmias and atrial fibrillation and discuss their role as potential therapeutic targets. PMID:24051368

Heijman, Jordi; Dewenter, Matthias; El-Armouche, Ali; Dobrev, Dobromir

2013-11-01

248

Dynamics of DNA strand exchange by Bxb1 integrase, a model serine site-specific recombinase  

NASA Astrophysics Data System (ADS)

Site-specific recombination breaks and rejoins DNA at specific sequences within synaptic complexes assembled by specialized recombinase enzymes. Structural data suggest that serine recombinases exchange duplex DNAs via a ``clutch plate'' mechanism allowing the fully cleaved duplex DNA ends to be exchanged by a rigid body rotation. We have directly observed this rotational motion for a simple serine recombinase, the Bxb1 phage integrase, using a single-DNA supercoiling-release assay which allows us to follow cleavage, rotation, religation and product release in real time. The molecular friction associated with the bearing is much larger than that found for type I topoisomerases in a similar assay. Experiments with recombination-incompetent and recombination-competent substrates lead to expected outcomes. We confirm our results in two-DNA braiding-relaxation experiments where synapse rotation can be directly observed in reactions on two long molecules.

Bai, Hua; Ghosh, Pallavi; Sun, Mingxuan; Grindley, Nigel; Hatfull, Graham; Marko, John F.

2010-03-01

249

Antimetastatic activity of a synthetic serine protease inhibitor, FOY-305 (Foypan).  

PubMed

Metastasis is one of the major causes of mortality in cancer. It is well known that the activities of cell surface serine proteases are especially enhanced in malignant tumors. Proteolytic degradation of the extracellular matrix and basal membrane is a crucial event for tumor cell invasion and metastasis formation. FOY-305 (Foypan), a remedy for tumor pancreatitis, is a broad spectrum synthetic serine protease inhibitor which inhibits enzymatic activities including trypsin, thrombin, kallikrein and plasmin. Using Lewis lung carcinoma cell, we found that FOY-305 inhibited both spontaneous and experimental pulmonary metastasis. Furthermore, the combined treatment of FOY-305 and a traditional anti-cancer drug, 5-FU or bleomycin, resulted in marked enhancement of anti-pulmonary metastatic activity. PMID:15796165

Ohkoshi, Motohiro; Sasaki, Yutaro

2005-01-01

250

Preliminary characterization of a Kazal-type serine protease inhibitor from Caiman crocodilus yacare plasma.  

PubMed

Blood serine protease inhibitors are becoming better understood and increasingly applied in blood clotting, cancer and other diseases. Reptiles are suitable models for blood coagulation and related processes, moreover, caiman is a good comparative model of a non-poisonous reptile. Recently, we reported the purification of a kininogen, the presence of proteases involved in blood clotting, and a serine protease inhibitor in Caiman crocodilus yacare plasma. In this paper, we described the partial sequence of an inhibitor (CcTI). The inhibitor is an 80-kDa protein, and it inactivates trypsin and chymotrypsin the hydrolysis of specific chromogenic substrates and in the degradation of gelatin. The inhibitor is member of Kazal-type inhibitor family and consists of several domains, its putative reactive site is Arg-His. PMID:10615009

Araujo, M S; Nunes, V A; Gozzo, A J; Sampaio, M U; Auerswald, E; Ura, N; Shimamoto, K; Sampaio, C A

1999-12-01

251

KSR-Based Medium Improves the Generation of High-Quality Mouse iPS Cells  

PubMed Central

Induced pluripotent stem (iPS) cells from somatic cells have great potential for regenerative medicine. The efficiency in generation of iPS cells has been significantly improved in recent years. However, the generation of high-quality iPS cells remains of high interest. Consistently, we demonstrate that knockout serum replacement (KSR)-based medium accelerates iPS cell induction and improves the quality of iPS cells, as confirmed by generation of chimeras and all iPS cell-derived offspring with germline transmission competency. Both alkaline phosphatase (AP) activity assay and expression of Nanog have been used to evaluate the efficiency of iPS cell induction and formation of ES/iPS cell colonies; however, appropriate expression of Nanog frequently indicates the quality of ES/iPS cells. Interestingly, whereas foetal bovine serum (FBS)-based media increase iPS cell colony formation, as revealed by AP activity, KSR-based media increase the frequency of iPS cell colony formation with Nanog expression. Furthermore, inhibition of MAPK/ERK by a specific inhibitor, PD0325901, in KSR- but not in FBS-based media significantly increases Nanog-GFP+ iPS cells. In contrast, addition of bFGF in KSR-based media decreases proportion of Nanog-GFP+ iPS cells. Remarkably, PD can rescue Nanog-GFP+ deficiency caused by bFGF. These data suggest that MAPK/ERK pathway influences high quality mouse iPS cells and that KSR- and PD-based media could enrich homogeneous authentic pluripotent stem cells. PMID:25171101

Liu, Kai; Wang, Fang; Ye, Xiaoying; Wang, Lingling; Yang, Jiao; Zhang, Jingzhuo; Liu, Lin

2014-01-01

252

Physicochemical and biological characteristics of DEAE-derivatized PS7 biopolymer of Beijerinckia indica.  

PubMed

Physicochemical and biological characteristics of the exopolysaccharide, PS7, produced from Beijerinckia indica were investigated. The PS7 weight fractions of Glc and GlcUA were 0.45 and 0.25, respectively, and the molar ratio of Glc:Rha:GalUA was approximately 5:1:1.3. The PS7 was chemically derivatized with diethylaminoethyl chloride-HCl (DEAE-HCl), and the resulting modified PS7 contained both positive and negative charges. The elemental and IR analyses were conducted to confirm the successful incorporation of DEAE groups into PS7. Large increase in nitrogen fraction was observed from the derivatized PS7 by elemental analysis. The characteristic CH(3) and CH(2) peaks originated from DEAE group were detected in (1)H NMR spectrum of the derivatized PS7 as well. Solubility of native PS7 was improved almost twice from 40 to 75% after DEAE-derivatization, while water holding capacity (WHC) drastically decreased from 10,026 to 245%. Oil binding capacity (OBC) of PS7 also significantly dropped from 1528 to 331% after the derivatization. The [eta] values of native and derivatized PS7 were 27.6 and 0.31 dL/g at 25 degrees C, respectively, which means that the DEAE-derivatization significantly decreased the [eta] of PS7. The bile acid binding capacity of PS7 was indirectly determined by measuring the holding capability of cholic acid inside the dialysis membrane. When PS7 was DEAE-derivatized, there was substantial decrease in the cholic acid retardation index (CRI). Up to 8-9h of dialysis, the derivatized PS7 hold 8.6% less of cholic acid compared to native one. PMID:17316786

Lee, Kyung Hee; Yoo, Sang-Ho; Baek, Seung Hee; Lee, Hyeon Gyu

2007-07-01

253

Mixed alkyl aryl phosphonate esters as quenched fluorescent activity-based probes for serine proteases.  

PubMed

Activity-based probes (ABPs) are powerful tools for the analysis of active enzyme species in whole proteomes, cells or animals. Quenched fluorescent ABPs (qABPs) can be applied for real time imaging, allowing the visualization of dynamic enzyme activation by fluorescent microscopy. Unfortunately, qABPs are only available for a few enzymes. We here describe the design and synthesis of qABPs for serine proteases based on a phosphonate ester scaffold. PMID:25553959

Serim, Sevnur; Baer, Philipp; Verhelst, Steven H L

2015-02-10

254

Distinct and Site-Specific Phosphorylation of the Retinoblastoma Protein at Serine 612 in Differentiated Cells  

PubMed Central

The retinoblastoma susceptibility protein (pRB) is a phosphoprotein that regulates cell cycle progression at the G1/S transition. In quiescent and early G1 cells, pRB predominantly exists in the active hypophosphorylated form. The cyclin/cyclin-dependent protein kinase complexes phosphorylate pRB at the late G1 phase to inactivate pRB. This event leads to the dissociation and activation of E2F family transcriptional factors. At least 12 serine/threonine residues in pRB are phosphorylated in vivo. Although there have been many reports describing bulk phosphorylation of pRB, detail research describing the function of each phosphorylation site remains unknown. Besides its G1/S inhibitory function, pRB is involved in differentiation, prevention of cell death and control of tissue fate. To uncover the function of phosphorylation of pRB in various cellular conditions, we have been investigating phosphorylation of each serine/threonine residue in pRB with site-specific phospho-serine/threonine antibodies. Here we demonstrate that pRB is specifically phosphorylated at Ser612 in differentiated cells in a known kinase-independent manner. We also found that pRB phosphorylated at Ser612 still associates with E2F-1 and tightly binds to nuclear structures including chromatin. Moreover, expression of the Ser612Ala mutant pRB failed to induce differentiation. The findings suggest that phosphorylation of Ser612 provides a distinct function that differs from the function of phosphorylation of other serine/threonine residues in pRB. PMID:24466208

Hattori, Takayuki; Uchida, Chiharu; Takahashi, Hirotaka; Yamamoto, Naoki; Naito, Mikihiko; Taya, Yoichi

2014-01-01

255

Structures of Plasmodium vivax serine hydroxymethyltransferase: implications for ligand-binding specificity and functional control  

PubMed Central

Plasmodium parasites, the causative agent of malaria, rely heavily on de novo folate biosynthesis, and the enzymes in this pathway have therefore been explored extensively for antimalarial development. Serine hydroxymethyltransferase (SHMT) from Plasmodium spp., an enzyme involved in folate recycling and dTMP synthesis, has been shown to catalyze the conversion of l- and d-serine to glycine (Gly) in a THF-dependent reaction, the mechanism of which is not yet fully understood. Here, the crystal structures of P. vivax SHMT (PvSHMT) in a binary complex with l-serine and in a ternary complex with d-serine (d-Ser) and (6R)-5-formyl­tetra­hydro­folate (5FTHF) provide clues to the mechanism underlying the control of enzyme activity. 5FTHF in the ternary-complex structure was found in the 6R form, thus differing from the previously reported structures of SHMT–Gly–(6S)-5FTHF from other organisms. This suggested that the presence of d-Ser in the active site can alter the folate-binding specificity. Investigation of binding in the presence of d-Ser and the (6R)- or (6S)-5FTHF enantiomers indicated that both forms of 5FTHF can bind to the enzyme but that only (6S)-5FTHF gives rise to a quinonoid intermediate. Likewise, a large surface area with a highly positively charged electrostatic potential surrounding the PvSHMT folate pocket suggested a preference for a polyglutamated folate substrate similar to the mammalian SHMTs. Furthermore, as in P. falciparum SHMT, a redox switch created from a cysteine pair (Cys125–Cys364) was observed. Overall, these results assert the importance of features such as stereoselectivity and redox status for control of the activity and specificity of PvSHMT. PMID:25478836

Chitnumsub, Penchit; Jaruwat, Aritsara; Riangrungroj, Pinpunya; Ittarat, Wanwipa; Noytanom, Krittikar; Oonanant, Worrapoj; Vanichthanankul, Jarunee; Chuankhayan, Phimonphan; Maenpuen, Somchart; Chen, Chun-Jung; Chaiyen, Pimchai; Yuthavong, Yongyuth; Leartsakulpanich, Ubolsree

2014-01-01

256

Chemically modified tetracycline-3 (CMT3): A novel inhibitor of the serine proteinase, elastase  

Microsoft Academic Search

Two classes of enzymes play an important role in connective tissue breakdown during various inflammatory diseases: serine proteinases and matrix metalloproteinases (MMPs). Tetracyclines (TCs) exhibit important anti-inflammatory and MMP-inhibitory properties that are unrelated to their antibacterial activities. Of the various TCs and their chemically modified NON-antibiotic analogs (CMTs) tested in vitro and in vivo, CMT-3 (6-demethyl-6-deoxy 4 de-dimethylamino tetracycline) has

Ying Gu; Hsi-Ming Lee; Sanford R. Simon; Lorne M. Golub

2011-01-01

257

Acanthamoeba polyphaga Mimivirus Prevents Amoebal Encystment-Mediating Serine Proteinase Expression and Circumvents Cell Encystment.  

PubMed

Acanthamoeba is a genus of free-living amoebas distributed worldwide. Few studies have explored the interactions between these protozoa and their infecting giant virus, Acanthamoeba polyphaga mimivirus (APMV). Here we show that, once the amoebal encystment is triggered, trophozoites become significantly resistant to APMV. Otherwise, upon infection, APMV is able to interfere with the expression of a serine proteinase related to amoebal encystment and the encystment can no longer be triggered. PMID:25520511

Boratto, Paulo; Albarnaz, Jonas Dutra; Almeida, Gabriel Magno de Freitas; Botelho, Lucas; Fontes, Alide Caroline Lima; Costa, Adriana Oliveira; Santos, Daniel de Assis; Bonjardim, Cláudio Antônio; La Scola, Bernard; Kroon, Erna Geessien; Abrahão, Jônatas Santos

2015-03-01

258

In vivo decomposition of phosphoserine and serine in noncollagenous protein from human dentin  

Microsoft Academic Search

Summary  HCl-soluble proteins in human dentin ranging in age from 3 to 45 years exhibit amino acid compositional changes consistent\\u000a with ?-elimination and hydrolysis of phosphoserine as well as dehydration and aldol cleavage of serine. This is the first\\u000a evidence of nonenzymatic mechanisms forin vivo degradation of hydroxy and substituted hydroxy amino acids in dentin. Decomposition of phosphoseryl residues reduces the

Patricia M. Masters

1985-01-01

259

Alternaria-derived serine protease activity drives IL-33–mediated asthma exacerbations  

PubMed Central

Background The fungal allergen Alternaria alternata is implicated in severe asthma and rapid onset life-threatening exacerbations of disease. However, the mechanisms that underlie this severe pathogenicity remain unclear. Objective We sought to investigate the mechanism whereby Alternaria was capable of initiating severe, rapid onset allergic inflammation. Methods IL-33 levels were quantified in wild-type and ST2?/? mice that lacked the IL-33 receptor given inhaled house dust mite, cat dander, or Alternaria, and the effect of inhibiting allergen-specific protease activities on IL-33 levels was assessed. An exacerbation model of allergic airway disease was established whereby mice were sensitized with house dust mite before subsequently being challenged with Alternaria (with or without serine protease activity), and inflammation, remodeling, and lung function assessed 24 hours later. Results Alternaria, but not other common aeroallergens, possessed intrinsic serine protease activity that elicited the rapid release of IL-33 into the airways of mice through a mechanism that was dependent upon the activation of protease activated receptor-2 and adenosine triphosphate signaling. The unique capacity of Alternaria to drive this early IL-33 release resulted in a greater pulmonary inflammation by 24 hours after challenge relative to the common aeroallergen house dust mite. Furthermore, this Alternaria serine protease–IL-33 axis triggered a rapid, augmented inflammation, mucus release, and loss of lung function in our exacerbation model. Conclusion Alternaria-specific serine protease activity causes rapid IL-33 release, which underlies the development of a robust TH2 inflammation and exacerbation of allergic airway disease. PMID:24636086

Snelgrove, Robert J.; Gregory, Lisa G.; Peiró, Teresa; Akthar, Samia; Campbell, Gaynor A.; Walker, Simone A.; Lloyd, Clare M.

2014-01-01

260

The protein kinase Pak3 positively regulates Raf1 activity through phosphorylation of serine 338  

Microsoft Academic Search

The pathway involving the signalling protein p21Ras propagates a range of extracellular signals from receptors on the cell membrane to the cytoplasm and nucleus. The Ras proteins regulate many effectors, including members of the Raf family of protein kinases. Ras-dependent activation of Raf-1 at the plasma membrane involves phosphorylation events, protein-protein interactions and structural changes. Phosphorylation of serine residues 338

Alastair J. King; Huaiyu Sun; Bruce Diaz; Darlene Barnard; Wenyan Miao; Shubha Bagrodia; Mark S. Marshall

1998-01-01

261

Purification and characterization of a neutral serine protease from non-sulfur purple photosynthetic bacterium  

Microsoft Academic Search

A neutral serine protease was purified as a homogeneous protein from the culture broth of photosynthetic bacterium T-20 by sequential chromatographies on columns of DEAE-cellulose, Toyopearl HW 55F, hydroxyapatite, and CM-cellulose. The molecular weight was estimated to be approximately 44,000 by SDS-PAGE, while the value of approximately 80,000 was obtained when the Hedrick-Smith method was used; this suggested that the

Moon-Sik Hyun; Shin-ichi Okuda; Kazuo Izaki

1989-01-01

262

Purification and Characterization of Myofibril-bound Serine Proteinase from Carp Cyprinus carpio Ordinary Muscle  

Microsoft Academic Search

1. A novel myofibril-bound serine proteinase (MBP) has been purified from ordinary muscle of the carp Cyprinus carpio. 2. It was solubilized from the myofibril fraction with acid treatment (under the conditions of 0.6 M KCl, pH 4.0), then purified by column chromatographic steps on Ultrogel AcA 54, and Arginine-Sepharose 4B. 3. The purified enzyme revealed a single protein band

Kiyoshi Osatomi; Hiroshi Sasai; Minjie Cao; Kenji Hara; Tadashi Ishihara

1997-01-01

263

Engineering of the Lactococcus lactis serine proteinase by construction of hybrid enzymes  

Microsoft Academic Search

Plasmids containing wild-type and hybrid proteinase genes were constructed from DNA fragments of the prtP genes of Lactococcus lactis strains Wg2 and SK11. These plasmids were introduced into the plasmid-free strain L. lactis MG1363. The serine proteinases produced by these L. lactis strains were isolated, and their cleavage specificity and rate towards ?s1-and ?-casein was investigated. The catalytic properties of

Pieter Vos; Ingrid J. Boerrigter; Girbe Buist; Alfred J. Haandrikman; Monique Nijhuis; Marjon B. de Reuver; Roland J. Siezen; Gerard Venema; Willem M. de Vos; Jan Kok

1991-01-01

264

Expression and Characterization of the Mycobacterium tuberculosis Serine\\/Threonine Protein Kinase PknB  

Microsoft Academic Search

PknB is a member of the newly discovered eukaryotic-like protein serine\\/threonine kinase (PSTK) family of proteins. The pknB gene was cloned and expressed in Escherichia coli. The active recombinant protein was purified and shown to be reactive with antiphosphoserine antibodies, as well as with antibodies to the phosphorylated eukaryotic Ser\\/Thr kinases mitogen-activated protein kinase kinase 3 and 6, P38, and

YOSSEF AV-GAY; SARWAT JAMIL; STEVEN J. DREWS

1999-01-01

265

Serine\\/threonine protein phosphatase inhibition enhances the effect of thymidylate synthase inhibition  

Microsoft Academic Search

Purpose The serine\\/threonine protein phosphatases 1 (PP1) and 2A (PP2A) are key enzymes in regulating entry into the cell cycle, mitosis and apoptosis. Inhibition of PP1 and PP2A is associated with enhanced S-phase entry culminating in G 2\\/M arrest and apoptotic cell death. Thymidylate synthase (TS) is a key regulatory enzyme in DNA synthesis, inhibition of which is often a

Jennette A. Sakoff; Ian J. Howitt; Stephen P. Ackland; Adam McCluskey

2004-01-01

266

Structures of Plasmodium vivax serine hydroxymethyltransferase: implications for ligand-binding specificity and functional control.  

PubMed

Plasmodium parasites, the causative agent of malaria, rely heavily on de novo folate biosynthesis, and the enzymes in this pathway have therefore been explored extensively for antimalarial development. Serine hydroxymethyltransferase (SHMT) from Plasmodium spp., an enzyme involved in folate recycling and dTMP synthesis, has been shown to catalyze the conversion of L- and D-serine to glycine (Gly) in a THF-dependent reaction, the mechanism of which is not yet fully understood. Here, the crystal structures of P. vivax SHMT (PvSHMT) in a binary complex with L-serine and in a ternary complex with D-serine (D-Ser) and (6R)-5-formyltetrahydrofolate (5FTHF) provide clues to the mechanism underlying the control of enzyme activity. 5FTHF in the ternary-complex structure was found in the 6R form, thus differing from the previously reported structures of SHMT-Gly-(6S)-5FTHF from other organisms. This suggested that the presence of D-Ser in the active site can alter the folate-binding specificity. Investigation of binding in the presence of D-Ser and the (6R)- or (6S)-5FTHF enantiomers indicated that both forms of 5FTHF can bind to the enzyme but that only (6S)-5FTHF gives rise to a quinonoid intermediate. Likewise, a large surface area with a highly positively charged electrostatic potential surrounding the PvSHMT folate pocket suggested a preference for a polyglutamated folate substrate similar to the mammalian SHMTs. Furthermore, as in P. falciparum SHMT, a redox switch created from a cysteine pair (Cys125-Cys364) was observed. Overall, these results assert the importance of features such as stereoselectivity and redox status for control of the activity and specificity of PvSHMT. PMID:25478836

Chitnumsub, Penchit; Jaruwat, Aritsara; Riangrungroj, Pinpunya; Ittarat, Wanwipa; Noytanom, Krittikar; Oonanant, Worrapoj; Vanichthanankul, Jarunee; Chuankhayan, Phimonphan; Maenpuen, Somchart; Chen, Chun Jung; Chaiyen, Pimchai; Yuthavong, Yongyuth; Leartsakulpanich, Ubolsree

2014-12-01

267

Structure of Soybean Serine Acetyltransferase and Formation of the Cysteine Regulatory Complex as a Molecular Chaperone*  

PubMed Central

Serine acetyltransferase (SAT) catalyzes the limiting reaction in plant and microbial biosynthesis of cysteine. In addition to its enzymatic function, SAT forms a macromolecular complex with O-acetylserine sulfhydrylase. Formation of the cysteine regulatory complex (CRC) is a critical biochemical control feature in plant sulfur metabolism. Here we present the 1.75–3.0 ? resolution x-ray crystal structures of soybean (Glycine max) SAT (GmSAT) in apoenzyme, serine-bound, and CoA-bound forms. The GmSAT-serine and GmSAT-CoA structures provide new details on substrate interactions in the active site. The crystal structures and analysis of site-directed mutants suggest that His169 and Asp154 form a catalytic dyad for general base catalysis and that His189 may stabilize the oxyanion reaction intermediate. Glu177 helps to position Arg203 and His204 and the ?1c-?2c loop for serine binding. A similar role for ionic interactions formed by Lys230 is required for CoA binding. The GmSAT structures also identify Arg253 as important for the enhanced catalytic efficiency of SAT in the CRC and suggest that movement of the residue may stabilize CoA binding in the macromolecular complex. Differences in the effect of cold on GmSAT activity in the isolated enzyme versus the enzyme in the CRC were also observed. A role for CRC formation as a molecular chaperone to maintain SAT activity in response to an environmental stress is proposed for this multienzyme complex in plants. PMID:24225955

Yi, Hankuil; Dey, Sanghamitra; Kumaran, Sangaralingam; Lee, Soon Goo; Krishnan, Hari B.; Jez, Joseph M.

2013-01-01

268

Taraxalisin – a serine proteinase from dandelion Taraxacum officinale Webb s.l  

Microsoft Academic Search

Latex of dandelion roots contains a serine proteinase that hydrolyzes a chromogenic peptide substrate Glp-Ala-Ala-Leu-pNA optimally at pH 8.0. Maximal activity of the proteinase in the roots is attained in April, at the beginning of plant development after the winter period. The protease was isolated by ammonium sulfate precipitation of the root extract followed by affinity chromatography on a Sepharose-Ala-Ala-Leu-mrp

G. N. Rudenskaya; A. M. Bogacheva; A. Preusser; A. V. Kuznetsova; Ya. E. Dunaevsky; B. N. Golovkin; V. M. Stepanov

1998-01-01

269

Regulation of Interferon Regulatory Factor3 by the Hepatitis C Virus Serine Protease  

Microsoft Academic Search

Persistent infections with hepatitis C virus (HCV) are likely to depend on viral inhibition of host defenses. We show that the HCV NS3\\/4A serine protease blocks the phosphorylation and effector action of interferon regulatory factor-3 (IRF-3), a key cellular antiviral signaling molecule. Disruption of NS3\\/4A protease function by mutation or a ketoamide peptidomimetic inhibitor relieved this blockade and restored IRF-3

Eileen Foy; Kui Li; Chunfu Wang; Rhea Sumpter; Masanori Ikeda; Stanley M. Lemon; Michael Gale

2003-01-01

270

Enhanced serine production by bone metastatic breast cancer cells stimulates osteoclastogenesis  

Microsoft Academic Search

Since bone metastatic breast cancer is an incurable disease, causing significant morbidity and mortality, an understanding\\u000a of the underlying molecular mechanisms would be highly valuable. Here, we describe in vitro and in vivo evidences for the\\u000a importance of serine biosynthesis in the metastasis of breast cancer to bone. We first characterized the bone metastatic propensity\\u000a of the MDA-MB-231(SA) cell line

Sirkku Pollari; Sanna-Maria Käkönen; Henrik Edgren; Maija Wolf; Pekka Kohonen; Henri Sara; Theresa Guise; Matthias Nees; Olli Kallioniemi

2011-01-01

271

Unique glycine-activated riboswitch linked to glycine-serine auxotrophy in SAR11.  

PubMed

The genome sequence of the marine bacterium 'Candidatus Pelagibacter ubique' and subsequent analyses have shown that while it has a genome as small as many obligate parasites, it nonetheless possesses a metabolic repertoire that allows it to grow as one of the most successful free-living cells in the ocean. An early report based on metabolic reconstruction indicated that SAR11 cells are prototrophs for all amino acids. However, here we report experimental evidence that 'Cand. P. ubique' is effectively auxotrophic for glycine and serine. With glucose and acetate added to seawater to supply organic carbon, the addition of 125 nM to 1.5 microM glycine to growth medium containing all other nutrients in excess resulted in a linear increase in maximum cell density from 1.14 x 10(6) cells ml(-1) to 8.16 x 10(6) cells ml(-1) (R(2) = 0.992). Serine was capable of substituting for glycine at 1.5 microM. 'Cand. P. ubique' contains a glycine-activated riboswitch preceding malate synthase, an unusual genomic context that is conserved in the SAR11 group. Malate synthase plays a critical role in central metabolism by enabling TCA intermediates to be regenerated through the glyoxylate cycle. In vitro analysis of this riboswitch indicated that it responds solely to glycine but not close structural analogues, such as glycine betaine, malate, glyoxylate, glycolate, alanine, serine or threonine. We conclude that 'Cand. P. ubique' is therefore a glycine-serine auxotroph that appears to use intracellular glycine level to regulate its use of carbon for biosynthesis and energy. Comparative genomics and metagenomics indicate that these conclusions may hold throughout much of the SAR11 clade. PMID:19125817

Tripp, H James; Schwalbach, Michael S; Meyer, Michelle M; Kitner, Joshua B; Breaker, Ronald R; Giovannoni, Stephen J

2009-01-01

272

Immunocytochemical demonstration of serine:pyruvate aminotransferase in peroxisomes and mitochondria of rat kidney  

Microsoft Academic Search

The light- and electron-microscopic localization of serine:pyruvate aminotransferase (SPT) in rat kidney was studied using immunoenzyme and protein A-gold techniques. Rat kidneys were fixed by perfusion through the abdominal aorta and small tissue slices were embedded in Epon, Lowicryl K4M, or LR Gold. The Epon was removed from the semithin sections, which were then stained using the immunoenzyme technique. Ultrathin

S. Yokota; T. Oda

1985-01-01

273

Molecular cloning and characterisation of DESC4, a new transmembrane serine protease  

Microsoft Academic Search

Type II transmembrane serine proteases (TTSPs) are a growing family of multidomain proteins. Among the TTSPs, a new subfamily of HAT\\/DESC1-like ( human airway trypsin-like protease\\/ differentially expressed in squamous cell carcinoma gene 1) proteases is emerging consisting so far of four members: DESC1–3 and HAT. The cDNA of a new member of this subfamily, named DESC4, was isolated from

M. Behrens; B. Bufe; H. Schmale; W. Meyerhof

2004-01-01

274

The serine-proline turn: a novel hydrogen-bonded template for designing peptidomimetics.  

PubMed

Serine-Proline (SP) dipeptide motifs have been shown to form unique hydrogen-bonding patterns in protein crystal structures. Peptides were designed to mimic these patterns by forming the 6 + 10 and the 9 + 10 hydrogen-bonded rings. Factors that contribute to the formation of SP turns include controlling backbone flexibility and amino acid chirality along with creating a hydrophobic environment around the intramolecular hydrogen bonds. PMID:22257322

Song, Benben; Bomar, Martha G; Kibler, Patrick; Kodukula, Krishna; Galande, Amit K

2012-02-01

275

Serine protease acylation proceeds with a subtle re-orientation of the histidine ring at the tetrahedral intermediate.  

PubMed

The acylation mechanism of a prototypical serine protease trypsin and its complete free energy reaction profile have been determined by Born-Oppenheimer ab initio QM/MM molecular dynamics simulations with umbrella sampling. PMID:21116528

Zhou, Yanzi; Zhang, Yingkai

2011-02-01

276

Studies on alkaline serine protease produced by Bacillus clausii GMBE 22.  

PubMed

An alkali tolerant Bacillus strain having extracellular serine alkaline protease activity was newly isolated from compost and identified as Bacillus clausii GMBE 22. An alkaline protease (AP22) was 4.66-fold purified in 51.5% yield from Bacillus clausii GMBE 22 by ethanol precipitation and DEAE-cellulose anion exchange chromatography. The purified enzyme was identified as serine protease by LC-ESI-MS analysis. Its complete inhibition by phenylmethanesulfonylfluoride (PMSF) also justified that it is a serine alkaline protease. The molecular weight of the enzyme is 25.4 kDa. Optimal temperature and pH values are 60 degrees C and 12.0, respectively. The enzyme showed highest specificity to N-Suc-Ala-Ala-Pro-Phe-pNA. The K(m) and k(cat) values for hydrolysis of this substrate are 0.347 mM and 1141 min(-1) respectively. The enzyme was affected by surface active agents to varying extents. The enzyme is stable for 2 h at 30 degrees C and pH 10.5. AP22 is also stable for 5 days over the pH range 9.0-11.0 at room temperature. AP22 has good pH stability compared with the alkaline proteases belonging to other strains of Bacillus clausii reported in the literature. PMID:19431045

Kazan, Dilek; Bal, Hulya; Denizci, Aziz Akin; Ozturk, Nurcin Celik; Ozturk, Hasan Umit; Dilgimen, Aydan Salman; Ozturk, Dilek Coskuner; Erarslan, Altan

2009-01-01

277

Serine Protease Variants Encoded by Echis ocellatus Venom Gland cDNA: Cloning and Sequencing Analysis  

PubMed Central

Envenoming by Echis saw-scaled viper is the leading cause of death and morbidity in Africa due to snake bite. Despite its medical importance, there have been few investigations into the toxin composition of the venom of this viper. Here, we report the cloning of cDNA sequences encoding four groups or isoforms of the haemostasis-disruptive Serine protease proteins (SPs) from the venom glands of Echis ocellatus. All these SP sequences encoded the cysteine residues scaffold that form the 6-disulphide bonds responsible for the characteristic tertiary structure of venom serine proteases. All the Echis ocellatus EoSP groups showed varying degrees of sequence similarity to published viper venom SPs. However, these groups also showed marked intercluster sequence conservation across them which were significantly different from that of previously published viper SPs. Because viper venom SPs exhibit a high degree of sequence similarity and yet exert profoundly different effects on the mammalian haemostatic system, no attempt was made to assign functionality to the new Echis ocellatus EoSPs on the basis of sequence alone. The extraordinary level of interspecific and intergeneric sequence conservation exhibited by the Echis ocellatus EoSPs and analogous serine proteases from other viper species leads us to speculate that antibodies to representative molecules should neutralise (that we will exploit, by epidermal DNA immunization) the biological function of this important group of venom toxins in vipers that are distributed throughout Africa, the Middle East, and the Indian subcontinent. PMID:20936075

Hasson, S. S.; Mothana, R. A.; Sallam, T. A.; Al-balushi, M. S.; Rahman, M. T.; Al-Jabri, A. A.

2010-01-01

278

Stimulation of MC38 tumor growth by insulin analog X10 involves the serine synthesis pathway.  

PubMed

Recent evidence suggests that type II diabetes is associated with increased risk and/or aggressive behavior of several cancers, including those arising from the colon. Concerns have been raised that endogenous hyperinsulinemia and/or exogenous insulin and insulin analogs might stimulate proliferation of neoplastic cells. However, the mechanisms underlying possible growth-promoting effects of insulin and insulin analogs in cancer cells in vivo, such as changes in gene expression, are incompletely described. We observed that administration of the insulin analog X10 significantly increased tumor growth and proliferation in a murine colon cancer model (MC38 cell allografts). Insulin and X10 altered gene expression in MC38 tumors in a similar fashion, but X10 was more potent in terms of the number of genes influenced and the magnitude of changes in gene expression. Many of the affected genes were annotated to metabolism, nutrient uptake, and protein synthesis. Strikingly, expression of genes encoding enzymes in the serine synthesis pathway, recently shown to be critical for neoplastic proliferation, was increased following treatment with insulin and X10. Using stable isotopic tracers and mass spectrometry, we confirmed that insulin and X10 increased glucose contribution to serine synthesis in MC38 cells. The data demonstrate that the tumor growth-promoting effects of insulin and X10 are associated with changes in expression of genes involved in cellular energy metabolism and reveal previously unrecognized effects of insulin and X10 on serine synthesis. PMID:22685267

Hvid, Henning; Fendt, Sarah-Maria; Blouin, Marie-José; Birman, Elena; Voisin, Gregory; Svendsen, Angela Manegold; Frank, Russell; Vander Heiden, Matthew G; Stephanopoulos, Gregory; Hansen, Bo Falck; Pollak, Michael

2012-08-01

279

Cross-phosphorylation of bacterial serine/threonine and tyrosine protein kinases on key regulatory residues  

PubMed Central

Bacteria possess protein serine/threonine and tyrosine kinases which resemble eukaryal kinases in their capacity to phosphorylate multiple substrates. We hypothesized that the analogy might extend further, and bacterial kinases may also undergo mutual phosphorylation and activation, which is currently considered as a hallmark of eukaryal kinase networks. In order to test this hypothesis, we explored the capacity of all members of four different classes of serine/threonine and tyrosine kinases present in the firmicute model organism Bacillus subtilis to phosphorylate each other in vitro and interact with each other in vivo. The interactomics data suggested a high degree of connectivity among all types of kinases, while phosphorylation assays revealed equally wide-spread cross-phosphorylation events. Our findings suggest that the Hanks-type kinases PrkC, PrkD, and YabT exhibit the highest capacity to phosphorylate other B. subtilis kinases, while the BY-kinase PtkA and the two-component-like kinases RsbW and SpoIIAB show the highest propensity to be phosphorylated by other kinases. Analysis of phosphorylated residues on several selected recipient kinases suggests that most cross-phosphorylation events concern key regulatory residues. Therefore, cross-phosphorylation events are very likely to influence the capacity of recipient kinases to phosphorylate substrates downstream in the signal transduction cascade. We therefore conclude that bacterial serine/threonine and tyrosine kinases probably engage in a network-type behavior previously described only in eukaryal cells. PMID:25278935

Shi, Lei; Pigeonneau, Nathalie; Ravikumar, Vaishnavi; Dobrinic, Paula; Macek, Boris; Franjevic, Damjan; Noirot-Gros, Marie-Francoise; Mijakovic, Ivan

2014-01-01

280

Serine/threonine/tyrosine protein kinase phosphorylates oleosin, a regulator of lipid metabolic functions.  

PubMed

Plant oils are stored in oleosomes or oil bodies, which are surrounded by a monolayer of phospholipids embedded with oleosin proteins that stabilize the structure. Recently, a structural protein, Oleosin3 (OLE3), was shown to exhibit both monoacylglycerol acyltransferase and phospholipase A(2) activities. The regulation of these distinct dual activities in a single protein is unclear. Here, we report that a serine/threonine/tyrosine protein kinase phosphorylates oleosin. Using bimolecular fluorescence complementation analysis, we demonstrate that this kinase interacts with OLE3 and that the fluorescence was associated with chloroplasts. Oleosin-green fluorescent protein fusion protein was exclusively associated with the chloroplasts. Phosphorylated OLE3 exhibited reduced monoacylglycerol acyltransferase and increased phospholipase A(2) activities. Moreover, phosphatidylcholine and diacylglycerol activated oleosin phosphorylation, whereas lysophosphatidylcholine, oleic acid, and Ca(2+) inhibited phosphorylation. In addition, recombinant peanut (Arachis hypogaea) kinase was determined to predominantly phosphorylate serine residues, specifically serine-18 in OLE3. Phosphorylation levels of OLE3 during seed germination were determined to be higher than in developing peanut seeds. These findings provide direct evidence for the in vivo substrate selectivity of the dual-specificity kinase and demonstrate that the bifunctional activities of oleosin are regulated by phosphorylation. PMID:22434039

Parthibane, Velayoudame; Iyappan, Ramachandiran; Vijayakumar, Anitha; Venkateshwari, Varadarajan; Rajasekharan, Ram

2012-05-01

281

HATL5: A Cell Surface Serine Protease Differentially Expressed in Epithelial Cancers  

PubMed Central

Over the last two decades, cell surface proteases belonging to the type II transmembrane serine protease (TTSP) family have emerged as important enzymes in the mammalian degradome, playing critical roles in epithelial biology, regulation of metabolic homeostasis, and cancer. Human airway trypsin-like protease 5 (HATL5) is one of the few family members that remains uncharacterized. Here we demonstrate that HATL5 is a catalytically active serine protease that is inhibited by the two Kunitz type serine protease inhibitors, hepatocyte growth factor activator inhibitor (HAI)-1 and 2, as well as by serpinA1. Full-length HATL5 is localized on the cell surface of cultured mammalian cells as demonstrated by confocal microscopy. HATL5 displays a relatively restricted tissue expression profile, with both transcript and protein present in the cervix, esophagus, and oral cavity. Immunohistochemical analysis revealed an expression pattern where HATL5 is localized on the cell surface of differentiated epithelial cells in the stratified squamous epithelia of all three of these tissues. Interestingly, HATL5 is significantly decreased in cervical, esophageal, and head and neck carcinomas as compared to normal tissue. Analysis of cervical and esophageal cancer tissue arrays demonstrated that the squamous epithelial cells lose their expression of HATL5 protein upon malignant transformation. PMID:24498351

Miller, Gregory S.; Zoratti, Gina L.; Murray, Andrew S.; Bergum, Christopher; Tanabe, Lauren M.; List, Karin

2014-01-01

282

Molecular cloning, expression, and anti-tumor activity of a novel serine protease from Arenicola cristata.  

PubMed

Arenicola cristata, a marine annelid, is a well-known and prized traditional Chinese medicine. However, the serine protease gene of A. cristata has not been cloned yet. In this study, a novel protease of A. cristata was cloned, sequenced, and expressed in Escherichia coli, and the functions of this recombinant protease were also investigated. The whole complementary DNA (cDNA) of this novel protease was of 980 bp in length and consisted of an open reading frame of 861 bp encoding 286 aa. Sequence analysis of the deduced amino acid sequence revealed that the protease belongs to the serine protease family. The active enzyme of the proposed A. cristata protease is composed of a signal peptide, a propeptide, and a mature polypeptide. The molecular weight of the recombinant mature protein was ~26 kDa after over-expression in E. coli. The recombinant protein significantly inhibited cell growth and induced cell apoptosis of esophageal squamous cell carcinoma (ESCC) in vitro, and reduced tumorigenicity in vivo. Furthermore, administration of the recombinant protein led to the activation of caspase-9 as well as down-regulation of Mcl-1 and Bcl-2. Taken together, our findings indicated that the recombinant serine protease of A. cristata could inhibit ESCC cell growth by mitochondrial apoptotic pathway and might act as a potential pharmacological agent for ESCC therapy. PMID:24709333

Zhao, Chunling; Ju, Jiyu

2014-06-01

283

Phosphorylation of serine 106 in Asef2 regulates cell migration and adhesion turnover.  

PubMed

Asef2, a 652-amino acid protein, is a guanine nucleotide exchange factor (GEF) that regulates cell migration and other processes via activation of Rho family GTPases, including Rac. Binding of the tumor suppressor adenomatous polyposis coli (APC) to Asef2 is known to induce its GEF activity; however, little is currently known about other modes of Asef2 regulation. Here, we investigated the role of phosphorylation in regulating Asef2 activity and function. Using high-resolution mass spectrometry (MS) and tandem mass spectrometry (MS/MS), we obtained complete coverage of all phosphorylatable residues and identified six phosphorylation sites. One of these, serine 106 (S106), was particularly intriguing as a potential regulator of Asef2 activity because of its location within the APC-binding domain. Interestingly, mutation of this serine to alanine (S106A), a non-phosphorylatable analogue, greatly diminished the ability of Asef2 to activate Rac, while a phosphomimetic mutation (serine to aspartic acid, S106D) enhanced Rac activation. Furthermore, expression of these mutants in HT1080 cells demonstrated that phosphorylation of S106 is critical for Asef2-promoted migration and for cell-matrix adhesion assembly and disassembly (adhesion turnover), which is a process that facilitates efficient migration. Collectively, our results show that phosphorylation of S106 modulates Asef2 GEF activity and Asef2-mediated cell migration and adhesion turnover. PMID:24874604

Evans, J Corey; Hines, Kelly M; Forsythe, Jay G; Erdogan, Begum; Shi, Mingjian; Hill, Salisha; Rose, Kristie L; McLean, John A; Webb, Donna J

2014-07-01

284

Structure-Based Mechanism for Early PLP-Mediated Steps of Rabbit Cytosolic Serine Hydroxymethyltransferase Reaction  

PubMed Central

Serine hydroxymethyltransferase catalyzes the reversible interconversion of L-serine and glycine with transfer of one-carbon groups to and from tetrahydrofolate. Active site residue Thr254 is known to be involved in the transaldimination reaction, a crucial step in the catalytic mechanism of all pyridoxal 5?-phosphate- (PLP-) dependent enzymes, which determines binding of substrates and release of products. In order to better understand the role of Thr254, we have expressed, characterized, and determined the crystal structures of rabbit cytosolic serine hydroxymethyltransferase T254A and T254C mutant forms, in the absence and presence of substrates. These mutants accumulate a kinetically stable gem-diamine intermediate, and their crystal structures show differences in the active site with respect to wild type. The kinetic and crystallographic data acquired with mutant enzymes permit us to infer that conversion of gem-diamine to external aldimine is significantly slowed because intermediates are trapped into an anomalous position by a misorientation of the PLP ring, and a new energy barrier hampers the transaldimination reaction. This barrier likely arises from the loss of the stabilizing hydrogen bond between the hydroxymethyl group of Thr254 and the ?-amino group of active site Lys257, which stabilizes the external aldimine intermediate in wild type SHMTs. PMID:23956983

Di Salvo, Martino L.; Scarsdale, J. Neel; Kazanina, Galina; Contestabile, Roberto; Schirch, Verne; Wright, H. Tonie

2013-01-01

285

PAK-dependent STAT5 serine phosphorylation is required for BCR-ABL-induced leukemogenesis  

PubMed Central

The transcription factor STAT5 (signal transducer and activator of transcription 5) is frequently activated in hematological malignancies and represents an essential signaling node downstream of the BCR-ABL oncogene. STAT5 can be phosphorylated at three positions, on a tyrosine and on the two serines S725 and S779. We have investigated the importance of STAT5 serine phosphorylation for BCR-ABL-induced leukemogenesis. In cultured bone marrow cells, expression of a STAT5 mutant lacking the S725 and S779 phosphorylation sites (STAT5SASA) prohibits transformation and induces apoptosis. Accordingly, STAT5SASA BCR-ABL+ cells display a strongly reduced leukemic potential in vivo, predominantly caused by loss of S779 phosphorylation that prevents the nuclear translocation of STAT5. Three distinct lines of evidence indicate that S779 is phosphorylated by group I p21-activated kinase (PAK). We show further that PAK-dependent serine phosphorylation of STAT5 is unaffected by BCR-ABL tyrosine kinase inhibitor treatment. Interfering with STAT5 phosphorylation could thus be a novel therapeutic approach to target BCR-ABL-induced malignancies. PMID:24263804

Berger, A; Hoelbl-Kovacic, A; Bourgeais, J; Hoefling, L; Warsch, W; Grundschober, E; Uras, I Z; Menzl, I; Putz, E M; Hoermann, G; Schuster, C; Fajmann, S; Leitner, E; Kubicek, S; Moriggl, R; Gouilleux, F; Sexl, V

2014-01-01

286

Serine proteases and protease-activated receptor 2-dependent allodynia: A novel cancer pain pathway  

PubMed Central

Mediators involved in the generation of pain in patients with cancer are poorly understood. Using a combined molecular, pharmacologic, behavioral, and genetic approach, we have identified a novel mechanism of cancer-dependent allodynia induced by protease-activated receptor 2 (PAR2). Here we show that human head and neck carcinoma cells have increased levels of proteolytic activity compared to normal human cell controls. Supernatant from human carcinoma cells, but not controls, caused marked and prolonged mechanical allodynia in mice, when administered into the hindpaw. This nociceptive effect was abolished by serine protease inhibition, diminished by mast cell-depletion and absent in PAR2-deficient mice. In addition, non-contact co-culture of trigeminal ganglion neurons with human head and neck carcinoma cells increased the proportion of neurons that exhibited PAR2-immunoreactivity. Our results point to a direct role for serine proteases and their receptor in the pathogenesis of cancer pain. This previously unrecognized cancer pain pathway has important therapeutic implications wherein serine protease inhibitors and PAR2 antagonists may be useful for the treatment of cancer pain. PMID:20189717

Lam, D.K.; Schmidt, B.L.

2010-01-01

287

Serine esterase and hemolytic activity in human cloned cytotoxic T lymphocytes  

PubMed Central

Target cell lysis by most murine cytotoxic T lymphocytes appears to be mediated by a complement (C9)-like protein called perforin, contained in high-density cytoplasmic granules. These granules also contain high levels of serine esterase activity, which may also play a role in cytolysis. Analysis of 17 cloned human cytotoxic T lymphocytes revealed the presence of serine esterase that is very similar to its murine counterpart in substrate and inhibitor specificities, pH optimum, and molecular mass; dot blot hybridization with synthetic oligonucleotides corresponding to the active sites of two known murine CTL esterases suggests homology to the murine enzyme HF. However, serine esterase was present at only approximately 10% of the level found in murine CTLs, and was not secreted during CTL-target cell interaction; moreover, hemolytic activity could not be detected in any of the seven cell lines tested. The results suggest that the human CTLs examined here kill their target cells by a mechanism different from that used by most cloned murine CTLs. PMID:3126252

1988-01-01

288

Exposure levels of asthmatic children to allergens, endotoxins, and serine proteases in a tropical environment.  

PubMed

A cross-sectional study was conducted in Bayamón, Puerto Rico, to identify and quantify indoor allergens, serine proteases, and bacterial endotoxin present in homes of asthmatic children. A total of 126 dust samples from houses were obtained from the entire mattress and bedside floor. Most of the patients had detectable levels of mite, cockroach, cat, and dog allergens. Mold allergens were found only in bedside floor dust samples. Mouse allergens were not detected. Forty-two percent, 36.5%, and 1.8% of the patients demonstrated exposures to sensitizing levels of mite, Bla g 1 and cat allergens, respectively. The percentage of patients exposed to high levels of allergens capable of triggering asthma symptoms was 33.3% and 26.4% for mite and Bla g 1 allergens. Only dog allergen, bacterial endotoxin, elastase, and trypsin were associated with asthma symptoms. Eighty-nine percent of the asthmatic children were exposed to endotoxin concentrations greater than 100 EU/mg dust, and more than half of the patients were exposed to high levels of serine proteases. Our study indicates that indoor concentrations of allergens traditionally associated with asthma symptoms and severity may not be applicable in tropical environments and highly ventilated households. In fact, in the study population, endotoxins, dog allergen, and serine proteases may play a dominant role in the induction of asthma symptoms. PMID:15281335

Montealegre, Federico; Fernández, Blanca; Delgado, Alexie; Fernández, Lisa; Román, Ayleen; Chardón, Domingo; Rodríguez-Santana, José; Medina, Vivian; Zavala, Diego; Bayona, Manuel

2004-06-01

289

Treatment of Post–Transfusion Graft–versus–Host Disease with Nafmostat Mesilate, a Serine Protease Inhibitor  

Microsoft Academic Search

Background: Cytotoxic T lymphocytes from donors are thought to injure the target organs in post–transfusion graft–versus–host disease (PT–GVHD) through perforin–granzyme– and Fas–dependent cell killings. The protease involved is a serine protease, and nafmostat mesilate (NM), a serine protease inhibitor, has been found to inhibit the in vitro allocytotoxicity of the T cell clone established from a patient with PT–GVHD, thus

Ryukichi Ryo; Katsuyasu Saigo; Makoto Hashimoto; Masatoshi Kohsaki; Masao Yasufuku; Norihisa Watanabe; Masayoshi Okada; Kenji Tadokoro; Takeo Juji

1999-01-01

290

Isolation, expression and characterization of a novel dual serine protease inhibitor, OH-TCI, from king cobra venom  

Microsoft Academic Search

Snake venom Kunitz\\/BPTI members are good tools for understanding of structure–functional relationship between serine proteases and their inhibitors. A novel dual Kunitz\\/BPTI serine proteinase inhibitor named OH-TCI (trypsin- and chymotrypsin-dual inhibitor from Ophiophagus hannah) was isolated from king cobra venom by three chromatographic steps of gel filtration, trypsin affinity and reverse phase HPLC. OH-TCI is composed of 58 amino acid

Ying-Ying He; Shu-Bai Liu; Wen-Hui Lee; Jin-Qiao Qian; Yun Zhang

2008-01-01

291

d Serine exposure resulted in gene expression changes implicated in neurodegenerative disorders and neuronal dysfunction in male Fischer 344 rats  

Microsoft Academic Search

d-Serine, an endogenous amino acid, is involved in many physiological processes through its interaction with the glycine binding\\u000a site of the N-methyl-d-aspartate (NMDA) receptor. It has important roles in development, learning, and cell death signaling. Recent evidence suggests\\u000a that decreased function of the NMDA receptor is related to the etiology of schizophrenia, and the use of d-serine as add-on therapy

Molly E. Davidson; Laura A. Kerepesi; Armando Soto; Victor T. Chan

2009-01-01

292

Purification and Functional Characterisation of Rhinocerase, a Novel Serine Protease from the Venom of Bitis gabonica rhinoceros  

PubMed Central

Background Serine proteases are a major component of viper venoms and are thought to disrupt several distinct elements of the blood coagulation system of envenomed victims. A detailed understanding of the functions of these enzymes is important both for acquiring a fuller understanding of the pathology of envenoming and because these venom proteins have shown potential in treating blood coagulation disorders. Methodology/Principal Findings In this study a novel, highly abundant serine protease, which we have named rhinocerase, has been isolated and characterised from the venom of Bitis gabonica rhinoceros using liquid phase isoelectric focusing and gel filtration. Like many viper venom serine proteases, this enzyme is glycosylated; the estimated molecular mass of the native enzyme is approximately 36kDa, which reduces to 31kDa after deglycosylation. The partial amino acid sequence shows similarity to other viper venom serine proteases, but is clearly distinct from the sequence of the only other sequenced serine protease from Bitis gabonica. Other viper venom serine proteases have been shown to exert distinct biological effects, and our preliminary functional characterization of rhinocerase suggest it to be multifunctional. It is capable of degrading ? and ? chains of fibrinogen, dissolving plasma clots and of hydrolysing a kallikrein substrate. Conclusions/Significance A novel multifunctional viper venom serine protease has been isolated and characterised. The activities of the enzyme are consistent with the known in vivo effects of Bitis gabonica envenoming, including bleeding disorders, clotting disorders and hypotension. This study will form the basis for future research to understand the mechanisms of serine protease action, and examine the potential for rhinocerase to be used clinically to reduce the risk of human haemostatic disorders such as heart attacks and strokes. PMID:20300193

Vaiyapuri, Sakthivel; Harrison, Robert A.; Bicknell, Andrew B.; Gibbins, Jonathan M.; Hutchinson, Gail

2010-01-01

293

Neutrophil Serine Proteinases Activate Human Nonepithelial Cells to Produce Inflammatory Cytokines Through Protease-Activated Receptor 21  

Microsoft Academic Search

Protease-activated receptors (PARs) compose a family of G protein-coupled receptors activated by proteolysis with exposure of their tethered ligand. Recently, we reported that a neutrophil-derived serine proteinase, proteinase 3 (PR3), activated human oral epithelial cells through PAR-2. The present study examined whether other neutrophil serine proteinases, human leukocyte elastase (HLE), and cathepsin G (Cat G) activate nonepithelial cells, human gingival

Akiko Uehara; Koji Muramoto; Haruhiko Takada; Shunji Sugawara

294

MicroRNA expression profiles of human iPS cells, retinal pigment epithelium derived from iPS, and fetal retinal pigment epithelium.  

PubMed

The objective of this report is to describe the protocols for comparing the microRNA (miRNA) profiles of human induced-pluripotent stem (iPS) cells, retinal pigment epithelium (RPE) derived from human iPS cells (iPS-RPE), and fetal RPE. The protocols include collection of RNA for analysis by microarray, and the analysis of microarray data to identify miRNAs that are differentially expressed among three cell types. The methods for culture of iPS cells and fetal RPE are explained. The protocol used for differentiation of RPE from human iPS is also described. The RNA extraction technique we describe was selected to allow maximal recovery of very small RNA for use in a miRNA microarray. Finally, cellular pathway and network analysis of microarray data is explained. These techniques will facilitate the comparison of the miRNA profiles of three different cell types. PMID:24999033

Greene, Whitney A; Muñiz, Alberto; Plamper, Mark L; Kaini, Ramesh R; Wang, Heuy-Ching

2014-01-01

295

Genetic transformation in the methanogen Methanococcus voltae PS  

NASA Technical Reports Server (NTRS)

Mutations causing requirements for histidine, purine, and vitamin B12 were obtained in strain PS of Methanococcus voltae (archaebacteria) upon irradiation with UV or gamma rays. The first two mutations were shown to revert at low frequencies and were used to demonstrate the occurrence of transformation with homologous, wild-type DNA. The transformation rates obtained for these presumably chromosomal markers were in the range of 2 to 100 transformants per microgram of DNA. Mutants resistant to 2-bromoethanesulfonate and to 5-methyl-DL-tryptophan were also isolated.

Bertani, G.; Baresi, L.

1987-01-01

296

Create and Publish a Hierarchical Progressive Survey (HiPS)  

NASA Astrophysics Data System (ADS)

Since 2009, the CDS promotes a method for visualizing based on the HEALPix sky tessellation. This method, called “Hierarchical Progressive Survey" or HiPS, allows one to display a survey progressively. It is particularly suited for all-sky surveys or deep fields. This visualization method is now integrated in several applications, notably Aladin, the SiTools/MIZAR CNES framework, and the recent HTML5 “Aladin Lite". Also, more than one hundred surveys are already available in this view mode. In this article, we will present the progress concerning this method and its recent adaptation to the astronomical catalogs such as the GAIA simulation.

Fernique, P.; Boch, T.; Pineau, F.; Oberto, A.

2014-05-01

297

Demonstration of a 2-ps transient x-ray laser  

Microsoft Academic Search

A time-resolved measurement of the output from the Ni-like Ag transient-collisional-excitation x-ray laser is described. An ultrafast x-ray streak camera was used to diagnose the output of the J=0-->1 4d-4p lasing line at 13.9 nm. The full width at half maximum duration of the x-ray pulse is measured to be of 1.9+\\/-0.7 ps at optimum conditions of pump laser irradiation.

A. Klisnick; J. Kuba; D. Ros; R. Smith; G. Jamelot; C. Chenais-Popovics; R. Keenan; S. J. Topping; C. L. Lewis; F. Strati; G. J. Tallents; D. Neely; R. Clarke; J. Collier; A. G. Macphee; F. Bortolotto; P. V. Nickles; K. A. Janulewicz

2002-01-01

298

Expression profiling and comparative analyses of seven midgut serine proteases from the yellow fever mosquito, Aedes aegypti.  

PubMed

Aedes aegypti utilizes blood for energy production, egg maturation and replenishment of maternal reserves. The principle midgut enzymes responsible for bloodmeal digestion are endoproteolytic serine-type proteases within the S1.A subfamily. While there are hundreds of serine protease-like genes in the A. aegypti genome, only five are known to be expressed in the midgut. We describe the cloning, sequencing and expression profiling of seven additional serine proteases and provide a genomic and phylogenetic assessment of these findings. Of the seven genes, four are constitutively expressed and three are transcriptionally induced upon blood feeding. The amount of transcriptional induction is strongly correlated among these genes. Alignments reveal that, in general, the conserved catalytic triad, active site and accessory catalytic residues are maintained in these genes and phylogenetic analysis shows that these genes fall within three distinct clades; trypsins, chymotrypsins and serine collagenases. Interestingly, a previously described trypsin consistently arose with other serine collagenases in phylogenetic analyses. These results suggest that multiple gene duplications have arisen within the S1.A subfamily of midgut serine proteases and/or that A. aegypti has evolved an array of proteases with a broad range of substrate specificities for rapid, efficient digestion of bloodmeals. PMID:20100490

Brackney, Doug E; Isoe, Jun; W C, Black; Zamora, Jorge; Foy, Brian D; Miesfeld, Roger L; Olson, Ken E

2010-07-01

299

Bacillus thuringiensis Cry3Aa protoxin intoxication of Tenebrio molitor induces widespread changes in the expression of serine peptidase transcripts.  

PubMed

The yellow mealworm, Tenebrio molitor, is a pest of stored grain products and is sensitive to the Bacillus thuringiensis (Bt) Cry3Aa toxin. As digestive peptidases are a determining factor in Cry toxicity and resistance, we evaluated the expression of peptidase transcripts in the midgut of T. molitor larvae fed either a control or Cry3Aa protoxin diet for 24 h (RNA-Seq), or in larvae exposed to the protoxin for 6, 12, or 24 h (microarrays). Cysteine peptidase transcripts (9) were similar to cathepsins B, L, and K, and their expression did not vary more than 2.5-fold in control and Cry3Aa-treated larvae. Serine peptidase transcripts (48) included trypsin, chymotrypsin and chymotrypsin-like, elastase 1-like, and unclassified serine peptidases, as well as homologs lacking functional amino acids. Highly expressed trypsin and chymotrypsin transcripts were severely repressed, and most serine peptidase transcripts were expressed 2- to 15-fold lower in Cry3Aa-treated larvae. Many serine peptidase and homolog transcripts were found only in control larvae. However, expression of a few serine peptidase transcripts was increased or found only in Cry3Aa-treated larvae. Therefore, Bt intoxication significantly impacted the expression of serine peptidases, potentially important in protoxin processing, while the insect maintained the production of critical digestive cysteine peptidases. PMID:22640634

Oppert, Brenda; Martynov, Alexander G; Elpidina, Elena N

2012-09-01

300

Prediction and Analysis of Post-Translational Pyruvoyl Residue Modification Sites from Internal Serines in Proteins  

PubMed Central

Most of pyruvoyl-dependent proteins observed in prokaryotes and eukaryotes are critical regulatory enzymes, which are primary targets of inhibitors for anti-cancer and anti-parasitic therapy. These proteins undergo an autocatalytic, intramolecular self-cleavage reaction in which a covalently bound pyruvoyl group is generated on a conserved serine residue. Traditional detections of the modified serine sites are performed by experimental approaches, which are often labor-intensive and time-consuming. In this study, we initiated in an attempt for the computational predictions of such serine sites with Feature Selection based on a Random Forest. Since only a small number of experimentally verified pyruvoyl-modified proteins are collected in the protein database at its current version, we only used a small dataset in this study. After removing proteins with sequence identities >60%, a non-redundant dataset was generated and was used, which contained only 46 proteins, with one pyruvoyl serine site for each protein. Several types of features were considered in our method including PSSM conservation scores, disorders, secondary structures, solvent accessibilities, amino acid factors and amino acid occurrence frequencies. As a result, a pretty good performance was achieved in our dataset. The best 100.00% accuracy and 1.0000 MCC value were obtained from the training dataset, and 93.75% accuracy and 0.8441 MCC value from the testing dataset. The optimal feature set contained 9 features. Analysis of the optimal feature set indicated the important roles of some specific features in determining the pyruvoyl-group-serine sites, which were consistent with several results of earlier experimental studies. These selected features may shed some light on the in-depth understanding of the mechanism of the post-translational self-maturation process, providing guidelines for experimental validation. Future work should be made as more pyruvoyl-modified proteins are found and the method should be evaluated on larger datasets. At last, the predicting software can be downloaded from http://www.nkbiox.com/sub/pyrupred/index.html. PMID:23805260

Jiang, Yang; Li, Bi-Qing; Zhang, Yuchao; Feng, Yuan-Ming; Gao, Yu-Fei; Zhang, Ning; Cai, Yu-Dong

2013-01-01

301

Inhibition of lung serine proteases in mice: a potentially new approach to control influenza infection  

PubMed Central

Background Host serine proteases are essential for the influenza virus life cycle because the viral haemagglutinin is synthesized as a precursor which requires proteolytic maturation. Therefore, we studied the activity and expression of serine proteases in lungs from mice infected with influenza and evaluated the effect of serine protease inhibitors on virus replication both in cell culture and in infected mice. Results Two different inbred mouse strains were investigated: DBA/2J as a highly susceptible and C57Bl/6J as a more resistant strain to influenza virus infection. The serine proteases from lung homogenates of mice exhibited pH optima of 10.00. Using the substrate Bz-Val-Gly-Arg-p-nitroanilide or in zymograms, the intensities of proteolysis increased in homogenates from both mouse strains with time post infection (p.i.) with the mouse-adapted influenza virus A/Puerto Rico/8/34 (H1N1; PR8). In zymograms at day 7 p.i., proteolytic bands were stronger and numerous in lung homogenates from DBA/2J than C57Bl/6J mice. Real-time PCR results confirmed differential expression of several lung proteases before and after infecting mice with the H1N1 virus. The most strongly up-regulated proteases were Gzma, Tmprss4, Elane, Ctrl, Gzmc and Gzmb. Pretreatment of mouse and human lung cell lines with the serine protease inhibitors AEBSF or pAB or a cocktail of both prior to infection with the H1N1 or the A/Seal/Massachusetts/1/80 (H7N7; SC35M) virus resulted in a decrease in virus replication. Pretreatment of C57Bl/6J mice with either AEBSF or a cocktail of AEBSF and pAB prior to infection with the H1N1 virus significantly reduced weight loss and led to a faster recovery of treated versus untreated mice while pAB alone exerted a very poor effect. After infection with the H7N7 virus, the most significant reduction of weight loss was obtained upon pretreatment with either the protease inhibitor cocktail or pAB. Furthermore, pretreatment of C57BL/6J mice with AEBSF prior to infection resulted in a significant reduction in the levels of both the H1N1 and H7N7 nucleoproteins in mice lungs and also a significant reduction in the levels of the HA transcript in the lungs of the H1N1- but not the H7N7-infected mice. Conclusion Multiple serine protease activities might be implicated in mediating influenza infection. Blocking influenza A virus infection in cultured lung epithelia and in mice by the used serine protease inhibitors may provide an alternative approach for treatment of influenza infection. PMID:21251300

2011-01-01

302

STS-52 PS MacLean, backup PS Tryggvason, and PI pose on JSC's CCT flight deck  

NASA Technical Reports Server (NTRS)

STS-52 Columbia, Orbiter Vehicle (OV) 102, Canadian Payload Specialist (PS) Steven G. MacLean (left) and backup Payload Specialist Bjarni V. Tryggvason (right) take a break from a camera training session in JSC's Crew Compartment Trainer (CCT). The two Canadian Space Agency (CSA) representatives pose on the CCT's aft flight deck with Canadian scientist David Zimick, the principal investigator (PI) for the materials experiment in low earth orbit (MELEO). MELEO is a component of the CANEX-2 experiment package, manifest to fly on the scheduled October 1992 STS-52 mission. The CCT is part of the shuttle Mockup and Integration Laboratory (MAIL) Bldg 9NE.

1992-01-01

303

Properties of Extruded PS-212 Type Self-Lubricating Materials  

NASA Technical Reports Server (NTRS)

Research has been underway at the NASA Lewis Research Center since the 1960's to develop high temperature, self-lubricating materials. The bulk of the research has been done in-house by a team of researchers from the Materials Division. A series of self-lubricating solid material systems has been developed over the years. One of the most promising is the composite material system referred to as PS-212 or PM-212. This material is a powder metallurgy product composed of metal bonded chromium carbide and two solid lubricating materials known to be self-lubricating over a wide temperature range. NASA feels this material has a wide potential in industrial applications. Simplified processing of this material would enhance its commercial potential. Processing changes have the potential to reduce processing costs, but tribological and physical properties must not be adversely affected. Extrusion processing has been employed in this investigation as a consolidation process for PM-212/PS-212. It has been successful in that high density bars of EX-212 (extruded PM-212) can readily be fabricated. Friction and strength data indicate these properties have been maintained or improved over the P.M. version. A range of extrusion temperatures have been investigated and tensile, friction, wear, and microstructural data have been obtained. Results indicate extrusion temperatures are not critical from a densification standpoint, but other properties are temperature dependent.

Waters, W. J.; Sliney, H. E.; Soltis, R. F.

1993-01-01

304

Capillary electrophoresis-laser induced fluorescence (CE-LIF) assay for measurement of intra-cellular D-Serine and serine racemase activity  

PubMed Central

An enantioselective capillary electrophoresis–laser induced fluorescence (CE-LIF) method for the analysis of D-Serine (D-Ser) in cellular matrices has been developed. The assay involves derivatization with FITC followed by CE-LIF using 0.5 mM hydroxyl propyl-?-cyclodextrin in borate buffer [80 mM, pH 9.3]. The method was able to resolve D-Ser and L-Ser with an enantioselectivity (?) of 1.03 and a Resolution (Rs) of 1.37. Linearity was established from 0.25 ?M – 100.00 ?M. The assay was also able to enantioselectively resolve 6 additional amino acid racemates. The method was applied to the determination of intra-cellular D-Ser concentrations in PC-12, C6, 1312N1 and HepG2 cell lines. This method was used to determine the concentration-dependent increases in D-Ser and associated EC50 values produced by L-Ser and the concentration-dependent decreases in D-Ser and associated IC50 values produced by glycine, a competitive inhibitor of serine racemase (SR). Western blot analysis determined that the PC-12 and C6 cell lines contained monomeric and dimeric forms of SR while the 1321N1 and HepG2 cells contained only the monomeric form. Although the SR dimer has been identified as the active form of the enzyme, all four of the tested cell lines expressed enzymatically active SR. PMID:22037294

Singh, Nagendra S.; Paul, Rajib K.; Sichler, Megan; Moaddel, Ruin; Bernier, Michel; Wainer, Irving W.

2011-01-01

305

IMPROVING THE PULP YIELD BY USING PS\\/AQ AND\\/OR TWO STAGE OXYGEN DELIGNIFICATION  

Microsoft Academic Search

The effect of polysulfide (PS) and anthraquinone (AQ) addition on kraft cooking is investigated together with oxygen delignification of the high-yield PS\\/AQ kraft pulps. Addition of polysulfide and AQ increases pulp yield. The yield benefit is considerably lowered when cooking to kappa numbers below 27-28. Oxygen delignification to about 55% delignification preserves the yield increase attained by PS\\/AQ addition. For

Rwaichi J. A. Minja

306

iPS Cells and Pseudoscience: a Huge Detour in Stem Cell Research  

Microsoft Academic Search

A point-by-point comparison of conventional definition on pseudoscience with the claims made in the iPS cell publications is made here. The conclusion of this comparison is that most claims made for the iPS cells are of nature of pseudoscience . The diversion of stem cell research by the mistakes and deceptions contained in the iPS cell publications represents a great

Shi V. Liu

2008-01-01

307

DRiPs Solidify: Progress in Understanding Endogenous MHC Class I Antigen Processing  

PubMed Central

Defective Ribosomal Products (DRiPs) are a subset of rapidly degraded polypeptides that provide peptide ligands for MHC class I molecules. Here, I review recent progress in understanding DRiP biogenesis. These findings place DRiPs at the center of the MHC class I antigen processing pathway, linking immunosurveillance of viruses and tumors to mechanisms of specialized translation and cellular compartmentalization. DRiPs enable the immune system to rapidly and sensitively detect alterations in cellular gene expression. PMID:21962745

Yewdell, Jonathan W.

2011-01-01

308

Non-Contact Measurements of Stiffness in Confined PS Films by Fluorescence and XPCS  

NASA Astrophysics Data System (ADS)

Fluorescence is used to detect stiffness in confined polystyrene (PS) films through the intensity ratio (I3/I1) of the dye molecule pyrene. Free-standing PS films show a softening (an increase in I3/I1) when the film thickness decreases below 400 nm, and a stiffening (a decrease in I3/I1) below thicknesses of 200 nm. Silica- and PDMS-supported PS films show no softening but report stiffening for films less than 200 nm thick, a result not in accord with the Tg reductions seen for PS on silica. X-ray photon correlation spectroscopy (XPCS) also reports stiffening in PS on silica through the relaxation times of capillary waves at the polymer surface. A two order of magnitude increase in relaxation time is observed for small in-plane wavevectors (q) in a 30 nm PS film compared to a 120 nm film. Bilayer films of PS supported on various bulk underlayers studied by XPCS indicate that lower substrate modulus leads to faster PS surface relaxation times. These are the first reported non-contact measurements related to stiffness in confined PS on silica.

Evans, Christopher; Narayanan, Suresh; Jiang, Zhang; Torkelson, John

2011-03-01

309

Absolute Magnitudes of Pan-STARRS PS1 Asteroids  

NASA Astrophysics Data System (ADS)

Absolute magnitude (H) of an asteroid is a fundamental parameter describing the size and the apparent brightness of the body. Because of its surface shape, properties and changing illumination, the brightness changes with the geometry and is described by the phase function governed by the slope parameter (G). Although many years have been spent on detailed observations of individual asteroids to provide H and G, vast majority of minor planets have H based on assumed G and due to the input photometry from multiple sources the errors of these values are unknown. We compute H of ~ 180 000 and G of few thousands asteroids observed with the Pan-STARRS PS1 telescope in well defined photometric systems. The mean photometric error is 0.04 mag. Because on average there are only 7 detections per asteroid in our sample, we employed a Monte Carlo (MC) technique to generate clones simulating all possible rotation periods, amplitudes and colors of detected asteroids. Known asteroid colors were taken from the SDSS database. We used debiased spin and amplitude distributions dependent on size, spectral class distributions of asteroids dependent on semi-major axis and starting values of G from previous works. H and G (G12 respectively) were derived by phase functions by Bowell et al. (1989) and Muinonen et al. (2010). We confirmed that there is a positive systematic offset between H based on PS1 asteroids and Minor Planet Center database up to -0.3 mag peaking at 14. Similar offset was first mentioned in the analysis of SDSS asteroids and was believed to be solved by weighting and normalizing magnitudes by observatory codes. MC shows that there is only a negligible difference between Bowell's and Muinonen's solution of H. However, Muinonen's phase function provides smaller errors on H. We also derived G and G12 for thousands of asteroids. For known spectral classes, slope parameters agree with the previous work in general, however, the standard deviation of G in our sample is twice as larger, most likely due to sparse phase curve sampling. In the near future we plan to complete the H and G determination for all PS1 asteroids (500,000) and publish H and G values online. This work was supported by NASA grant No. NNX12AR65G.

Veres, Peter; Jedicke, R.; Fitzsimmons, A.; Denneau, L.; Wainscoat, R.; Bolin, B.; PS1SC Collaboration

2013-10-01

310

A novel fibrinolytic serine protease from the polychaete Nereis (Neanthes) virens (Sars): purification and characterization.  

PubMed

A novel fibrinolytic serine protease has been identified and purified to homogeneity from the coelomic fluid of polychaete Nereis (Neanthes) virens (Sars), and named N-V protease. N-V protease is a 29kDa single chain protein with an isoelectric point of pH 4.5. It hydrolyzes Aalpha-chain of fibrinogen with a high efficiency, and the Bbeta- and gamma-chains (Aalpha>Bbeta>gamma) with a lower efficiency. The proteolytic activity peaks at pH 7.8 is 45 degrees C. The activity is completely inhibited by serine protease inhibitors DFP (I(50)=5.8 x 10(-4)M) and PMSF (I(50)=5.5 x 10(-2)M), and almost completely by TLCK (I(50)=7.7 x 10(-1) M). But aprotinin, elastinal, SBTI, benzamidine, PCMB, EDTA, EGTA, iodoacetate, E64, and beta-mercaptoethanol have no effect on the protease activity. Therefore, N-V protease is identified as a serine protease. The primary amino acid sequence of N-V protease was determined by mass spectrometry (N-V protease, No. P83433). According to the MALDI-TOF MS analysis, there is no existing protein in the NCBI Non-redundant Protein Sequence Database that matches the N-V protease sequence. Therefore, N-V protease is a novel and special protein in N. virens. Furthermore, we have successfully established an expression cDNA library from the whole body of N. virens (data not shown). PMID:16950556

Zhang, Yunlong; Cui, Jiayue; Zhang, Rui; Wang, Yanpin; Hong, Min

2007-01-01

311

Mechanistic insights into the inhibition of serine proteases by monocyclic lactams.  

PubMed

Although originally discovered as inhibitors of pencillin-binding proteins, beta-lactams have more recently found utility as serine protease inhibitors. Indeed through their ability to react irreversibly with nucleophilic serine residues they have proved extraordinarily successful as enzyme inhibitors. Consequently there has been much speculation as to the reason for the general effectiveness of beta-lactams as antibacterials or inhibitors of hydrolytic enzymes. The interaction of analogous beta- and gamma-lactams with a serine protease was investigated. Three series of gamma-lactams based upon monocyclic beta-lactam inhibitors of elastase [Firestone, R. A. et al. (1990) Tetrahedron 46, 2255-2262.] but with an extra methylene group inserted between three of the bonds in the ring were synthesized. Their interaction with porcine pancreatic elastase and their efficacy as inhibitors were evaluated through the use of kinetic, NMR, mass spectrometric, and X-ray crystallographic analyses. The first series, with the methylene group inserted between C-3 and C-4 of the beta-lactam template, were readily hydrolyzed but were inactive or very weakly active as inhibitors. The second series, with the methylene group between C-4 and the nitrogen of the beta-lactam template, were inhibitory and reacted reversibly with PPE to form acyl-enzyme complexes, which were stable with respect to hydrolysis. The third series, with the methylene group inserted between C-2 and C-3, were not hydrolyzed and were not inhibitors consistent with lack of binding to PPE. Comparison of the crystal structure of the acyl-enzyme complex formed between PPE and a second series gamma-lactam and that formed between PPE and a peptide [Wilmouth, R. C., et al. (1997) Nat. Struct. Biol. 4, 456-462.] reveals why the complexes formed with this series were resistant to hydrolysis and suggests ways in which stable acyl-enzyme complexes might be obtained from monocyclic gamma-lactam-based inhibitors. PMID:10387042

Wilmouth, R C; Kassamally, S; Westwood, N J; Sheppard, R J; Claridge, T D; Aplin, R T; Wright, P A; Pritchard, G J; Schofield, C J

1999-06-22

312

Role of Serine/Threonine Phosphatase (SP-STP) in Streptococcus pyogenes Physiology and Virulence*  

PubMed Central

Reversible phosphorylation is the key mechanism regulating several cellular events in prokaryotes and eukaryotes. In prokaryotes, signal transduction is perceived to occur primarily via the two-component signaling system involving histidine kinases and cognate response regulators. Although an alternative regulatory pathway controlled by the eukaryote-type serine/threonine kinase (Streptococcus pyogenes serine/threonine kinase; SP-STK) has been shown to modulate bacterial growth, division, adherence, invasion, and virulence in group A Streptococcus (GAS; S. pyogenes), the precise role of the co-transcribing serine/threonine phosphatase (SP-STP) has remained enigmatic. In this context, this is the first report describing the construction and characterization of non-polar SP-STP mutants in two different strains of Type M1 GAS. The STP knock-out mutants displayed increased bacterial chain lengths in conjunction with thickened cell walls, significantly reduced capsule and hemolysin production, and restoration of the phenotypes postcomplementation. The present study also reveals important contribution of cognately regulated-reversible phosphorylation by SP-STK/SP-STP on two major response regulators of two-component systems, WalRK and CovRS. We also demonstrate a distinct role of SP-STP in terms of expression of surface proteins and SpeB in a strain-specific manner. Further, the attenuation of virulence in the absence of STP and its restoration only in the complemented strains that were generated by the use of a low copy plasmid and not by a high copy one emphasize not only the essential role of STP in virulence but also highlight the tightly regulated SP-STP/SP-STK-mediated cognate functions. SP-STP thus is an important regulator of GAS virulence and plays a critical role in GAS pathogenesis. PMID:21917918

Agarwal, Shivani; Agarwal, Shivangi; Pancholi, Preeti; Pancholi, Vijay

2011-01-01

313

Molecular Genetic Analysis of Midgut Serine Proteases in Aedes aegypti Mosquitoes  

PubMed Central

Digestion of blood meal proteins by midgut proteases provides anautogenous mosquitoes with the nutrients required to complete the gonotrophic cycle. Inhibition of protein digestion in the midgut of blood feeding mosquitoes could therefore provide a strategy for population control. Based on recent reports indicating that the mechanism and regulation of protein digestion in blood fed female Aedes aegypti mosquitoes is more complex than previously thought, we used a robust RNAi knockdown method to investigate the role of four highly expressed midgut serine proteases in blood meal metabolism. We show by Western blotting that the early phase trypsin protein (AaET) is maximally expressed at 3 h post blood meal (PBM), and that AaET is not required for the protein expression of three late phase serine proteases, AaLT (late trypsin), AaSPVI (5G1), and AaSPVII. Using the trypsin substrate analog BApNA to analyze in vitro enzyme activity in midgut extracts from single mosquitoes, we found that knockdown of AaSPVI expression caused a 77.6% decrease in late phase trypsin-like activity, whereas, knockdown of AaLT and AaSPVII expression had no significant effect on BApNA activity. In contrast, injection of AaLT, AaSPVI, and AaSPVII dsRNA inhibited degradation of endogenous serum albumin protein using an in vivo protease assay, as well as, significantly decreased egg production in both the first and second gonotrophic cycles (p<0.001). These results demonstrate that AaLT, AaSPVI, and AaSPVII all contribute to blood protein digestion and oocyte maturation, even though AaSPVI is the only abundant midgut late phase serine protease that appears to function as a classic trypsin enzyme. PMID:19883761

Isoe, Jun; Rascón, Alberto A.; Kunz, Susan; Miesfeld, Roger L.

2009-01-01

314

Molecular genetic analysis of midgut serine proteases in Aedes aegypti mosquitoes.  

PubMed

Digestion of blood meal proteins by midgut proteases provides anautogenous mosquitoes with the nutrients required to complete the gonotrophic cycle. Inhibition of protein digestion in the midgut of blood feeding mosquitoes could therefore provide a strategy for population control. Based on recent reports indicating that the mechanism and regulation of protein digestion in blood fed female Aedes aegypti mosquitoes is more complex than previously thought, we used a robust RNAi knockdown method to investigate the role of four highly expressed midgut serine proteases in blood meal metabolism. We show by Western blotting that the early phase trypsin protein (AaET) is maximally expressed at 3 h post-blood meal (PBM), and that AaET is not required for the protein expression of three late phase serine proteases, AaLT (late trypsin), AaSPVI (5G1), and AaSPVII. Using the trypsin substrate analog BApNA to analyze in vitro enzyme activity in midgut extracts from single mosquitoes, we found that knockdown of AaSPVI expression caused a 77.6% decrease in late phase trypsin-like activity, whereas, knockdown of AaLT and AaSPVII expression had no significant effect on BApNA activity. In contrast, injection of AaLT, AaSPVI, and AaSPVII dsRNA inhibited degradation of endogenous serum albumin protein using an in vivo protease assay, as well as, significantly decreased egg production in both the first and second gonotrophic cycles (P < 0.001). These results demonstrate that AaLT, AaSPVI, and AaSPVII all contribute to blood protein digestion and oocyte maturation, even though AaSPVI is the only abundant midgut late phase serine protease that appears to function as a classic trypsin enzyme. PMID:19883761

Isoe, Jun; Rascón, Alberto A; Kunz, Susan; Miesfeld, Roger L

2009-12-01

315

Middle East respiratory syndrome coronavirus infection mediated by the transmembrane serine protease TMPRSS2.  

PubMed

The Middle East respiratory syndrome coronavirus (MERS-CoV) utilizes host proteases for virus entry into lung cells. In the current study, Vero cells constitutively expressing type II transmembrane serine protease (Vero-TMPRSS2 cells) showed larger syncytia at 18 h after infection with MERS-CoV than after infection with other coronaviruses. Furthermore, the susceptibility of Vero-TMPRSS2 cells to MERS-CoV was 100-fold higher than that of non-TMPRSS2-expressing parental Vero cells. The serine protease inhibitor camostat, which inhibits TMPRSS2 activity, completely blocked syncytium formation but only partially blocked virus entry into Vero-TMPRSS2 cells. Importantly, the coronavirus is thought to enter cells via two distinct pathways, one mediated by TMPRSS2 at the cell surface and the other mediated by cathepsin L in the endosome. Simultaneous treatment with inhibitors of cathepsin L and TMPRSS2 completely blocked virus entry into Vero-TMPRSS2 cells, indicating that MERS-CoV employs both the cell surface and the endosomal pathway to infect Vero-TMPRSS2 cells. In contrast, a single camostat treatment suppressed MERS-CoV entry into human bronchial submucosal gland-derived Calu-3 cells by 10-fold and virus growth by 270-fold, although treatment with both camostat and (23,25)-trans-epoxysuccinyl-L-leucylamindo-3-methylbutane ethyl ester, a cathepsin inhibitor, or treatment with leupeptin, an inhibitor of cysteine, serine, and threonine peptidases, was no more efficacious than treatment with camostat alone. Further, these inhibitors were not efficacious against MERS-CoV infection of MRC-5 and WI-38 cells, which were derived from lung, but these characters differed from those of mature pneumocytes. These results suggest that a single treatment with camostat is sufficient to block MERS-CoV entry into a well-differentiated lung-derived cell line. PMID:24027332

Shirato, Kazuya; Kawase, Miyuki; Matsuyama, Shutoku

2013-12-01

316

Middle East Respiratory Syndrome Coronavirus Infection Mediated by the Transmembrane Serine Protease TMPRSS2  

PubMed Central

The Middle East respiratory syndrome coronavirus (MERS-CoV) utilizes host proteases for virus entry into lung cells. In the current study, Vero cells constitutively expressing type II transmembrane serine protease (Vero-TMPRSS2 cells) showed larger syncytia at 18 h after infection with MERS-CoV than after infection with other coronaviruses. Furthermore, the susceptibility of Vero-TMPRSS2 cells to MERS-CoV was 100-fold higher than that of non-TMPRSS2-expressing parental Vero cells. The serine protease inhibitor camostat, which inhibits TMPRSS2 activity, completely blocked syncytium formation but only partially blocked virus entry into Vero-TMPRSS2 cells. Importantly, the coronavirus is thought to enter cells via two distinct pathways, one mediated by TMPRSS2 at the cell surface and the other mediated by cathepsin L in the endosome. Simultaneous treatment with inhibitors of cathepsin L and TMPRSS2 completely blocked virus entry into Vero-TMPRSS2 cells, indicating that MERS-CoV employs both the cell surface and the endosomal pathway to infect Vero-TMPRSS2 cells. In contrast, a single camostat treatment suppressed MERS-CoV entry into human bronchial submucosal gland-derived Calu-3 cells by 10-fold and virus growth by 270-fold, although treatment with both camostat and (23,25)-trans-epoxysuccinyl-l-leucylamindo-3-methylbutane ethyl ester, a cathepsin inhibitor, or treatment with leupeptin, an inhibitor of cysteine, serine, and threonine peptidases, was no more efficacious than treatment with camostat alone. Further, these inhibitors were not efficacious against MERS-CoV infection of MRC-5 and WI-38 cells, which were derived from lung, but these characters differed from those of mature pneumocytes. These results suggest that a single treatment with camostat is sufficient to block MERS-CoV entry into a well-differentiated lung-derived cell line. PMID:24027332

Shirato, Kazuya; Kawase, Miyuki

2013-01-01

317

Serine Proteolytic Pathway Activation Reveals an Expanded Ensemble of Wound Response Genes in Drosophila  

PubMed Central

After injury to the animal epidermis, a variety of genes are transcriptionally activated in nearby cells to regenerate the missing cells and facilitate barrier repair. The range and types of diffusible wound signals that are produced by damaged epidermis and function to activate repair genes during epidermal regeneration remains a subject of very active study in many animals. In Drosophila embryos, we have discovered that serine protease function is locally activated around wound sites, and is also required for localized activation of epidermal repair genes. The serine protease trypsin is sufficient to induce a striking global epidermal wound response without inflicting cell death or compromising the integrity of the epithelial barrier. We developed a trypsin wounding treatment as an amplification tool to more fully understand the changes in the Drosophila transcriptome that occur after epidermal injury. By comparing our array results with similar results on mammalian skin wounding we can see which evolutionarily conserved pathways are activated after epidermal wounding in very diverse animals. Our innovative serine protease-mediated wounding protocol allowed us to identify 8 additional genes that are activated in epidermal cells in the immediate vicinity of puncture wounds, and the functions of many of these genes suggest novel genetic pathways that may control epidermal wound repair. Additionally, our data augments the evidence that clean puncture wounding can mount a powerful innate immune transcriptional response, with different innate immune genes being activated in an interesting variety of ways. These include puncture-induced activation only in epidermal cells in the immediate vicinity of wounds, or in all epidermal cells, or specifically in the fat body, or in multiple tissues. PMID:23637905

Patterson, Rachel A.; Juarez, Michelle T.; Hermann, Anita; Sasik, Roman; Hardiman, Gary; McGinnis, William

2013-01-01

318

Development and characterization of sub-100 ps photomultiplier tubes  

SciTech Connect

We describe the evaluation of a microchannel plate (MCP) photomultiplier tube (PMT), incorporating a 3 {mu}m pore MCP and constant voltage anode and cathode gaps. The use of the small pore size results in PMTs with response functions of the order of 85 ps full-width-half-maximum, while the constant electric field across the anode and cathode gaps produces a uniform response function over the entire operating range of the device. The PMT was characterized on a number of facilities and employed on gas Cherenkov detectors fielded on various deuterium tritium fuel (DT) implosions on the Omega Laser Facility at the University of Rochester. The Cherenkov detectors are part of diagnostic development to measure Gamma ray reaction history for DT implosions on the National Ignition Facility.

Horsfield, C. J.; Rubery, M. S. [AWE, Aldermaston, Reading RGR 4PR (United Kingdom); Mack, J. M.; Young, C. S.; Herrmann, H. W.; Caldwell, S. E.; Evans, S. C.; Sedilleo, T. J.; Kim, Y. H.; McEvoy, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Milnes, J. S.; Howorth, J. [Photek Ltd., 26 Castleham Rd., St. Leonards-on-Sea, East Sussex TN38 9NS (United Kingdom); Davis, B.; O'Gara, P. M.; Garza, I. [National Security Technologies, 2621 Losee Rd., North Las Vegas, Nevada 89030 (United States); Miller, E. K. [National Security Technologies, LLC, Santa Barbara, California 94551-0808 (United States); Stoeffl, W. [Lawrence Livermore National Laboratory, Livermore, California 93111 (United States); Ali, Z. [National Security Technologies, LO, Livermore, California 94551-2710 (United States)

2010-10-15

319

Glassy worms of PS-PEO block copolymers  

NASA Astrophysics Data System (ADS)

A novel class of rigid worm micelles formed by PS-PEO dilock copolymers are described. The worms exhibit unique hinged motion about defects, with the defect density falling drastically at higher molecular weights. The glassiness of the system is demonstrated using FRAP analysis. Stiffness of the worms is estimated in terms of tangent-tangent correlation along the backbone, and by the magnitude of angle fluctuations about the hinges. The backbone flexibility is found to be only weakly dependent on the temperature up to 80 ^oC. Breaking of glassiness, including stiffness and morphology control using organic solvents and a fluid diblock, are described. A simple method to engineer worm shape during formation process is presented. The rheological properties of the worms studied under parallel plate geometry, along with visualization of the worms under shear are presented.

Vijayan, Kandaswamy; Cheng, Debbie; Discher, Dennis

2007-03-01

320

Sub-10ps monolithic and low-power photodetector readout  

SciTech Connect

Recent advances in photon detectors have resulted in high-density imaging arrays that offer many performance and cost advantages. In particular, the excellent transit time spread of certain devices show promise to provide tangible benefits in applications such as Positron Emission Tomography (PET). Meanwhile, high-density, high-performance readout techniques have not kept on pace for exploiting these developments. Photodetector readout for next generation high event rate particle identification and time-resolved PET requires a highly-integrated, low-power, and cost-effective readout technique. We propose fast waveform sampling as a method that meets these criteria and demonstrate that sub-10ps resolution can be obtained for an existing device.

Varner, Gary S.; Ruckman, Larry L.

2009-02-20

321

Clozapine, but not haloperidol, enhances glial d-serine and L-glutamate release in rat frontal cortex and primary cultured astrocytes  

PubMed Central

BACKGROUND AND PURPOSE Deficient transmission at the glutamate NMDA receptor is considered a key component of the pathophysiology of schizophrenia. However, the effects of antipsychotic drugs on the release of the endogenous NMDA receptor partial agonist, d-serine, remain to be clarified. EXPERIMENTAL APPROACH We determined the interaction between antipsychotic drugs (clozapine and haloperidol) and transmission-modulating toxins (tetanus toxin, fluorocitrate, tetrodotoxin) on the release of L-glutamate and d-serine in the medial prefrontal cortex (mPFC) of freely moving rats, using microdialysis, and primary cultures of astrocytes using extreme high-pressure liquid chromatography. KEY RESULTS Release of L-glutamate and d-serine in the mPFC and in cultured astrocytes was inhibited by tetanus toxin (a synaptobrevin inhibitor) and fluorocitrate (a glial toxin), whereas tetrodotoxin (a voltage-sensitive Na+ blocker) inhibited depolarization-induced L-glutamate release in the mPFC without affecting that of d-serine. Clozapine (1 and 5 mg·kg?1), but not haloperidol (0.5 and 1 mg·kg?1), dose-dependently increased L-glutamate and d-serine release from both astrocytes and mPFC. Clozapine-induced release of L-glutamate and d-serine was also reduced by tetanus toxin and fluorocitrate. Tetrodotoxin reduced clozapine-induced mPFC L-glutamate release but not that of d-serine. Clozapine-induced L-glutamate release preceded clozapine-induced d-serine release. MK-801 (a NMDA receptor antagonist) inhibited the delayed clozapine-induced L-glutamate release without affecting that of d-serine. CONCLUSIONS AND IMPLICATIONS Clozapine predominantly activated glial exocytosis of d-serine, and this clozapine-induced d-serine release subsequently enhances neuronal L-glutamate release via NMDA receptor activation. The enhanced d-serine associated glial transmission seems a novel mechanism of action of clozapine but not haloperidol. PMID:21880034

Tanahashi, Shunske; Yamamura, Satoshi; Nakagawa, Masanori; Motomura, Eishi; Okada, Motohiro

2012-01-01

322

The tomato gene Pti1 encodes a serine\\/threonine kinase that is phosphorylated by Pto and is involved in the hypersensitive response  

Microsoft Academic Search

The Pto gene encodes a serine\\/threonine kinase that confers resistance to bacterial speck disease in tomato. Using the yeast two-hybrid system, we identified a second serine\\/threonine kinase, Pto-interacting 1 (Pti1), that physically interacts with Pto. Crossphosphorylation assays revealed that Pto specifically phosphorylates Ptil and that Ptil does not phosphorylate Pto. Fen, another serine\\/threonine kinase from tomato that is closely related

Jianmin Zhou; Ying-Tsu Loh; Ray A. Bressan; Gregory B. Martin

1995-01-01

323

Expression levels of serine/glycine metabolism-related proteins in triple negative breast cancer tissues.  

PubMed

To evaluate the expression levels of serine/glycine metabolism-related proteins (PHGDH, PSAT, PSPH, SHMT, and GLDC) in six different subtypes of triple negative breast cancer (TNBC) patients and gain insight into their implications. Formalin-fixed, paraffin-embedded tissues from 129 TNBC patients were assembled into tissue microarrays. Immunohistochemical staining was performed for serine/glycine metabolism-related proteins (PHGDH, PSAT, PSPH, SHMT, and GLDC) and surrogate immunohistochemical markers (CK5/6, EGFR, claudin 3, claudin 4, claudin 7, E-cadherin, STAT1, interleukin-8 [IL-8], AR, and GGT-1) for identifying the molecular subtype of TNBC. TNBC subtype classifications included the following: basal-like (CK5/6-positive and/or EGFR-positive), molecular apocrine (AR-positive and/or GGT-1-positive), claudin-low (claudin 3-, claudin 4-, claudin 7-negative and/or E-cadherin-negative), immune-related (IL-8-negative and stromal STAT1-positive), mixed (features from two or more of the four subtypes), and null (no features from any of the four subtypes). Tissues from basal marker-positive patients showed increased expression levels of tumoral PHGDH compared with those from basal marker-negative patients (p?=?0.029); lack of stromal SHMT1 expression was significantly correlated with T stage (p?=?0.016). Multivariate Cox analysis revealed that a lack of stromal SHMT1 expression was an independent prognostic factor for predicting a shorter disease-free survival period (hazard ratio 4.002, 95 % confidence interval [CI] 1.077-14.83, p?=?0.038); furthermore, a lack of tumoral PHGDH expression was predictive of a shorter overall survival rate (hazard ratio 3.053, 95 % CI 1.002-9.305, p?=?0.050). In conclusion, the most abundantly expressed serine/glycine metabolism-related protein in basal-like TNBC tissues was tumoral PHGDH, and expression levels of stromal SHMT1 and tumoral PHGDH were inversely correlated with clinical prognostic factors. Also, this study is the first to assess serine/glycine relationships at the protein level in regards to clinical outcomes. PMID:24390667

Noh, Songmi; Kim, Do Hee; Jung, Woo Hee; Koo, Ja Seung

2014-05-01

324

Enthalpies and constants of dissociation for D,L-Alanyl-D,L-Serine at 298 K  

NASA Astrophysics Data System (ADS)

Protolytic equilibria in aqueous solutions of D,L-alanyl-D,L-serine are studied by means of potentiometry and calorimetry. The dissociation constants and thermal effects of this reaction of the dipeptide are determined at 298.15 K and ionic strengths of 0.1, 0.3, 0.5, and 1.0 (KNO3). The standard thermodynamic characteristics (p K°, ?r G°, ?r H°, and ?r S°) of the studied equilibria are calculated. The final results are compared with the corresponding data on the related compounds.

Gridchin, S. N.; Pyreu, D. F.

2015-01-01

325

The structure of serine hydroxymethyltransferase as modeled by homology and validated by site-directed mutagenesis.  

PubMed Central

We describe a model for the three-dimensional structure of E. coli serine hydroxymethyltransferase based on its sequence homology with other PLP enzymes of the alpha-family and whose tertiary structures are known. The model suggests that certain amino acid residues at the putative active site of the enzyme can adopt specific roles in the catalytic mechanism. These proposals were supported by analysis of the properties of a number of site-directed mutants. New active site features are also proposed for further experimental testing. PMID:9761478

Pascarella, S.; Angelaccio, S.; Contestabile, R.; Delle Fratte, S.; Di Salvo, M.; Bossa, F.

1998-01-01

326

Phosphorylation of insulin receptor substrate-1 serine 307 correlates with JNK activity in atrophic skeletal muscle  

NASA Technical Reports Server (NTRS)

c-Jun NH(2)-terminal kinase (JNK) has been shown to negatively regulate insulin signaling through serine phosphorylation of residue 307 within the insulin receptor substrate-1 (IRS-1) in adipose and liver tissue. Using a rat hindlimb suspension model for muscle disuse atrophy, we found that JNK activity was significantly elevated in atrophic soleus muscle and that IRS-1 was phosphorylated on Ser(307) prior to the degradation of the IRS-1 protein. Moreover, we observed a corresponding reduction in Akt activity, providing biochemical evidence for the development of insulin resistance in atrophic skeletal muscle.

Hilder, Thomas L.; Tou, Janet C L.; Grindeland, Richard E.; Wade, Charles E.; Graves, Lee M.

2003-01-01

327

Synthesis and biochemical evaluation of triazole/tetrazole-containing sulfonamides against thrombin and related serine proteases  

PubMed Central

A small library of 25 triazole/tetrazole-based sulfonamides have been synthesized and further evaluated for their inhibitory activity against thrombin, trypsin, tryptase and chymase. In general, the triazole-based sulfonamides inhibited thrombin more efficiently than the tetrazole counterparts. Particularly, compound 26 showed strong thrombin inhibition (Ki =880 nM) and significant selectivity against other human related serine proteases like trypsin (Ki =729 µM). Thrombin binding affinity of the same compound was determined by ITC and demonstrated that the binding of this new triazole-based scaffold is enthalpically driven, making it a good candidate for further development. PMID:21807511

Siles, Rogelio; Kawasaki, Yuko; Ross, Patrick; Freire, Ernesto

2011-01-01

328

Immunisation against a serine protease inhibitor reduces intensity of Plasmodium berghei infection in mosquitoes.  

PubMed

The mosquito innate immune response is able to clear the majority of Plasmodium parasites. This immune clearance is controlled by a number of regulatory molecules including serine protease inhibitors (serpins). To determine whether such molecules could represent a novel target for a malaria transmission-blocking vaccine, we vaccinated mice with Anopheles gambiae serpin-2. Antibodies against Anopheles gambiae serpin-2 significantly reduced the infection of a heterologous Anopheles species (Anopheles stephensi) by Plasmodium berghei, however this effect was not observed with Plasmodium falciparum. Therefore, this approach of targeting regulatory molecules of the mosquito immune system may represent a novel approach to transmission-blocking malaria vaccines. PMID:23872520

Williams, Andrew R; Zakutansky, Sara E; Miura, Kazutoyo; Dicks, Matthew D J; Churcher, Thomas S; Jewell, Kerry E; Vaughan, Aisling M; Turner, Alison V; Kapulu, Melissa C; Michel, Kristin; Long, Carole A; Sinden, Robert E; Hill, Adrian V S; Draper, Simon J; Biswas, Sumi

2013-10-01

329

Immunization against a serine protease inhibitor reduces intensity of Plasmodium berghei infection in mosquitoes  

PubMed Central

The mosquito innate immune response is able to clear the majority of Plasmodium parasites. This immune clearance is controlled by a number of regulatory molecules including serine protease inhibitors (serpins). To determine whether such molecules could represent a novel target for a malaria transmission-blocking vaccine, we vaccinated mice with Anopheles gambiae serpin-2 (AgSRPN2). Antibodies against AgSRPN2 significantly reduced the infection of a heterologous Anopheles species (Anopheles stephensi) by Plasmodium berghei, however this effect was not observed with Plasmodium falciparum. Therefore, this approach of targeting regulatory molecules of the mosquito immune system may represent a novel approach to transmission-blocking malaria vaccines. PMID:23872520

Williams, Andrew R.; Zakutansky, Sara E.; Miura, Kazutoyo; Dicks, Matthew J. D.; Churcher, Thomas S.; Jewell, Kerry E.; Vaughan, Aisling M.; Turner, Alison V.; Kapulu, Melissa C.; Michel, Kristin; Long, Carole A.; Sinden, Robert E.; Hill, Adrian V. S.; Draper, Simon J.; Biswas, Sumi

2013-01-01

330

Viscoelastic properties of pressure overload hypertrophied myocardium: effect of serine protease treatment  

NASA Technical Reports Server (NTRS)

To determine whether and to what extent one component of the extracellular matrix, fibrillar collagen, contributes causally to abnormalities in viscoelasticity, collagen was acutely degraded by activation of endogenous matrix metalloproteinases (MMPs) with the serine protease plasmin. Papillary muscles were isolated from normal cats and cats with right ventricular pressure overload hypertrophy (POH) induced by pulmonary artery banding. Plasmin treatment caused MMP activation, collagen degradation, decreased the elastic stiffness constant, and decreased the viscosity constant in both normal and POH muscles. Thus, whereas many mechanisms may contribute to the abnormalities in myocardial viscoelasticity in the POH myocardium, changes in fibrillar collagen appear to play a predominant role.

Stroud, Jason D.; Baicu, Catalin F.; Barnes, Mary A.; Spinale, Francis G.; Zile, Michael R.

2002-01-01

331

Campylobacter jejuni gene cj0511 encodes a serine peptidase essential for colonisation  

PubMed Central

According to MEROPS peptidase database, Campylobacter species encode 64 predicted peptidases. However, proteolytic properties of only a few of these proteins have been confirmed experimentally. In this study we identified and characterised a Campylobacter jejuni gene cj0511 encoding a novel peptidase. The proteolytic activity associated with this enzyme was demonstrated in cell lysates. Moreover, enzymatic studies conducted with a purified protein confirmed a prediction of it being a serine peptidase. Furthermore, cj0511 mutant was found to be severely attenuated in chicken colonisation model, suggesting a role of the Cj0511 protein in infection. PMID:24918062

Karlyshev, A.V.; Thacker, G.; Jones, M.A.; Clements, M.O.; Wren, B.W.

2014-01-01

332

Chirality effects on proline-substituted serine octamers revealed by infrared photodissociation spectroscopy.  

PubMed

Chiral preferences exist in proline-substituted serine octamers. For ions of [L-Ser6 + Pro2]H(+), the stability preference is [L-Ser6 + L-Pro2]H(+) > [L-Ser6 + D-Pro2]H(+) > [L-Ser6 + L-Pro1 + D-Pro1]H(+). Infrared photodissociation (IRPD) experiments were performed for the observed proline-substituted octamer ions in the range from 2700 to 3750 cm(-1). Chiral differentiation was achieved using the IRPD method, and the progressive changes in IRPD spectra due to the substitution were also reflected. PMID:24305867

Liao, Guanhua; Yang, Yijie; Kong, Xianglei

2014-01-28

333

Multiple risk pathways for schizophrenia converge in serine racemase knockout mice, a mouse model of NMDA receptor hypofunction  

PubMed Central

Schizophrenia is characterized by reduced hippocampal volume, decreased dendritic spine density, altered neuroplasticity signaling pathways, and cognitive deficits associated with impaired hippocampal function. We sought to determine whether this diverse pathology could be linked to NMDA receptor (NMDAR) hypofunction, and thus used the serine racemase-null mutant mouse (SR?/?), which has less than 10% of normal brain d-serine, an NMDAR coagonist. We found that d-serine was necessary for the maintenance of long-term potentiation in the adult hippocampal dentate gyrus and for full NMDAR activity on granule cells. SR?/? mice had reduced dendritic spines and hippocampal volume. These morphological changes were paralleled by diminished BDNF/Akt/mammalian target of rapamycin (mTOR) signaling and impaired performance on a trace-conditioning memory task. Chronic d-serine treatment normalized the electrophysiological, neurochemical, and cognitive deficits in SR?/? mice. These results demonstrate that NMDAR hypofunction can reproduce the numerous hippocampal deficits associated with schizophrenia, which can be reversed by chronic peripheral d-serine treatment. PMID:23729812

Balu, Darrick T.; Li, Yan; Puhl, Matthew D.; Benneyworth, Michael A.; Basu, Alo C.; Takagi, Shunsuke; Bolshakov, Vadim Y.; Coyle, Joseph T.

2013-01-01

334

In vivo contribution of serine proteases to the proteolytic activation of ?ENaC in aldosterone-infused rats.  

PubMed

Aldosterone plays an important role in the regulation of blood pressure by modulating the activity of the epithelial sodium channel (ENaC) that consists of ?-, ?-, and ?-subunits. Aldosterone induces a molecular weight shift of ?ENaC from 85 to 70 kDa that is necessary for the channel activation. In vitro experiments demonstrated that a dual cleavage mechanism is responsible for this shift. It has been postulated that furin executes the primary cleavage in the Golgi and that the second cleavage is provided by other serine proteases such as prostasin or plasmin at the plasma membrane. However, the in vivo contribution of serine proteases to this cleavage remains unclear. To address this issue, we administered the synthetic serine protease inhibitor camostat mesilate (CM) to aldosterone-infused rats. CM decreased the abundance of the 70-kDa form of ENaC and led to a new 75-kDa form with a concomitant increase in the urinary Na-to-K ratio. Because CM inhibits the protease activity of serine proteases such as prostasin and plasmin, but not furin, our findings strongly indicate that CM inhibited the second cleavage of ?ENaC and subsequently suppressed ENaC activity. The results of our current studies also suggest the possibility that the synthetic serine protease inhibitor CM might represent a new strategy for the treatment of salt-sensitive hypertension in humans. PMID:22832922

Uchimura, Kohei; Kakizoe, Yutaka; Onoue, Tomoaki; Hayata, Manabu; Morinaga, Jun; Yamazoe, Rika; Ueda, Miki; Mizumoto, Teruhiko; Adachi, Masataka; Miyoshi, Taku; Shiraishi, Naoki; Sakai, Yoshiki; Tomita, Kimio; Kitamura, Kenichiro

2012-10-01

335

Purification and Gene Cloning of ?-Methylserine Aldolase from Ralstonia sp. Strain AJ110405 and Application of the Enzyme in the Synthesis of ?-Methyl-l-Serine?  

PubMed Central

By screening microorganisms that are capable of assimilating ?-methyl-dl-serine, we detected ?-methylserine aldolase in Ralstonia sp. strain AJ110405, Variovorax paradoxus AJ110406, and Bosea sp. strain AJ110407. A homogeneous form of this enzyme was purified from Ralstonia sp. strain AJ110405, and the gene encoding the enzyme was cloned and expressed in Escherichia coli. The enzyme appeared to be a homodimer consisting of identical subunits, and its molecular mass was found to be 47 kDa. It contained 0.7 to 0.8 mol of pyridoxal 5?-phosphate per mol of subunit and could catalyze the interconversion of ?-methyl-l-serine to l-alanine and formaldehyde in the absence of tetrahydrofolate. Formaldehyde was generated from ?-methyl-l-serine but not from ?-methyl-d-serine, l-serine, or d-serine. ?-Methyl-l-serine synthesis activity was detected when l-alanine was used as the substrate. In contrast, no activity was detected when d-alanine was used as the substrate. In the ?-methyl-l-serine synthesis reaction, the enzymatic activity was inhibited by an excess amount of formaldehyde, which was one of the substrates. We used cells of E. coli as a whole-cell catalyst to express the gene encoding ?-methylserine aldolase and effectively obtained a high yield of optically pure ?-methyl-l-serine using l-alanine and formaldehyde. PMID:18952881

Nozaki, Hiroyuki; Kuroda, Shinji; Watanabe, Kunihiko; Yokozeki, Kenzo

2008-01-01

336

The inhibitory effect of 2-deoxyglucose on insulin receptor autophosphorylation does not depend on known serine phosphorylation sites or other conserved serine residues of the receptor beta-subunit.  

PubMed

Hyperglycemia induces insulin resistance in diabetic patients. It is known that supraphysiological levels of D-glucose or 2-deoxyglucose inhibit the insulin receptor and it is speculated that this effect is mediated by serine phosphorylation of the insulin receptor beta-subunit and other proteins of the insulin signaling chain. To test this hypothesis we prepared point mutations of the human insulin receptor where serine was exchanged to alanine at 16 different positions, either at known phosphorylation sites or at positions which are conserved in different tyrosine kinase receptors. These receptor constructs were expressed in HEK 293 cells and the effect of 2-deoxyglucose (25 mM) on insulin (100 nM) induced receptor autophosphorylation was studied. 2-Deoxyglucose consistently inhibits insulin stimulated autophosphorylation of all constructs to the same degree as observed in wild-type human insulin receptor. The data suggest that none of the chosen serine positions are involved in 2-deoxyglucose induced receptor inhibition. PMID:10338114

Strack, V; Bossenmaier, B; Stoyanov, B; Mosthaf, L; Kellerer, M; Lammers, R; Häring, H U

1999-04-23

337

A Novel Serine Protease Secreted by Medicinal Maggots Enhances Plasminogen Activator-Induced Fibrinolysis  

PubMed Central

Maggots of the blowfly Lucilia sericata are used for the treatment of chronic wounds. As haemostatic processes play an important role in wound healing, this study focused on the effects of maggot secretions on coagulation and fibrinolysis. The results showed that maggot secretions enhance plasminogen activator-induced formation of plasmin and fibrinolysis in a dose- and time-dependent manner. By contrast, coagulation was not affected by secretions. Biochemical studies indicated that a novel serine protease within secretions, designated Sericase, cleaved plasminogen to several fragments. Recombinant Sericase degraded plasminogen leading amongst others to the formation of the mini-plasminogen like fragment Val454-plasminogen. In addition, the presence of a non-proteolytic cofactor in secretions was discovered, which plays a role in the enhancement of plasminogen activator-induced fibrinolysis by Sericase. We conclude from our in vitro studies that the novel serine protease Sericase, with the aid of a non-proteolytic cofactor, enhances plasminogen activator-induced fibrinolysis. PMID:24647546

van der Plas, Mariena J. A.; Andersen, Anders S.; Nazir, Sheresma; van Tilburg, Nico H.; Oestergaard, Peter R.; Krogfelt, Karen A.; van Dissel, Jaap T.; Hensbergen, Paul J.

2014-01-01

338

Crystal Structure of a Novel Viral Protease with a Serine/Lysine Catalytic Dyad Mechanism  

SciTech Connect

The blotched snakehead virus (BSNV), an aquatic birnavirus, encodes a polyprotein (NH2-pVP2-X-VP4-VP3-COOH) that is processed through the proteolytic activity of its own protease (VP4) to liberate itself and the viral proteins pVP2, X and VP3. The protein pVP2 is further processed by VP4 to give rise to the capsid protein VP2 and four structural peptides. We report here the crystal structure of a VP4 protease from BSNV, which displays a catalytic serine/lysine dyad in its active site. This is the first crystal structure of a birnavirus protease and the first crystal structure of a viral protease that utilizes a lysine general base in its catalytic mechanism. The topology of the VP4 substrate binding site is consistent with the enzymes substrate specificity and a nucleophilic attack from the si-face of the substrates scissile bond. Despite low levels of sequence identity, VP4 shows similarities in its active site to other characterized Ser/Lys proteases such as signal peptidase, LexA protease and Lon protease. Together, the structure of VP4 provides insights into the mechanism of a recently characterized clan of serine proteases that utilize a lysine general base and reveals the structure of potential targets for antiviral therapy, especially for other related and economically important viruses, such as infectious bursal disease virus in poultry and infectious pancreatic necrosis virus in aquaculture.

Feldman,A.; Lee, J.; Delmas, B.; Paetzel, M.

2006-01-01

339

Azurocidin and a homologous serine protease from neutrophils. Differential antimicrobial and proteolytic properties.  

PubMed Central

Two 29-kD polypeptides, azurocidin and p29b, were purified to homogeneity from human neutrophils by acid extraction of azurophil granule membrane-associated material followed by gel filtration and reverse-phase chromatography. Azurocidin and p29b share NH2-terminal sequence homology with each other as well as with elastase, cathepsin G, and other serine proteases. p29b bound [3H]diisopropyl fluorophosphate and hydrolyzed elastin, casein, and hemoglobin. A peptide substrate for p29b could not be identified. Azurocidin neither bound [3H]diisopropyl fluorophosphate nor hydrolyzed any of the proteins, peptides, or esters tested. In microbicidal assays, purified azurocidin was comparable to p29b in activity against Escherichia coli, Streptococcus faecalis, and Candida albicans. The antimicrobial activity of azurocidin was enhanced under mildly acidic conditions, but was inhibited in a dose-dependent manner by NaCl, CaCl2, or serum. Immunoblot analysis with monospecific antibodies localized greater than 90% of the azurocidin and greater than 75% of the p29b to azurophil granule-rich fractions of PMN lysates. Immunoelectron microscopy confirmed the localization of azurocidin to the azurophil granules. Azurocidin associated with the azurophil granule membrane, but did not appear to be an integral membrane protein. Thus, azurocidin and p29b are members of a family of serine protease homologs stored in azurophil granules and may play a role in inflammatory and antimicrobial processes involving PMN. Images PMID:2312733

Campanelli, D; Detmers, P A; Nathan, C F; Gabay, J E

1990-01-01

340

Purification and characterization of manganese-dependent alkaline serine protease from Bacillus pumilus TMS55.  

PubMed

The purification and characterization of a Mn2+-dependent alkaline serine protease produced by Bacillus pumilus TMS55 were investigated. The enzyme was purified in three steps: concentrating the crude enzyme using ammonium sulfate precipitation, followed by gel filtration and cation-exchange chromatography. The purified protease had a molecular mass of approximately 35 kDa, was highly active over a broad pH range of 7.0 to 12.0, and remained stable over a pH range of 7.5 to 11.5. The optimum temperature for the enzyme activity was found to be 60 degreesC. PMSF and AEBSF (1 mM) significantly inhibited the protease activity, indicating that the protease is a serine protease. Mn2+ ions enhanced the activity and stability of the enzyme. In addition, the purified protease remained stable with oxidants (H2O2, 2%) and organic solvents (25%), such as benzene, hexane, and toluene. Therefore, these characteristics of the protease and its dehairing ability indicate its potential for a wide range of commercial applications. PMID:21301188

Ibrahim, Kalibulla Syed; Muniyandi, Jeyaraj; Karutha Pandian, Shunmugiah

2011-01-01

341

Diversity of Serine Hydrolase Activities of Unchallenged and Botrytis-infected Arabidopsis thaliana*S?  

PubMed Central

Activity-based protein profiling is a powerful method to display enzyme activities in proteomes and provides crucial information on enzyme activity rather than protein or transcript abundance. We applied activity-based protein profiling using fluorophosphonate-based probes to display the activities of Ser hydrolases in the model plant Arabidopsis thaliana. Multidimensional protein identification technology and in-gel analysis of fluorophosphonate-labeled leaf extracts revealed over 50 Ser hydrolases, including dozens of proteases, esterases, and lipases, representing over 10 different enzyme families. Except for some well characterized Ser hydrolases like subtilases TPP2 and ARA12, prolyl oligopeptidase acylamino acid-releasing enzyme, serine carboxypeptidase-like SNG1 and BRS1, carboxylesterase-like CXE12, methylesterases MES2 and MES3, and S-formylglutathione hydrolase, the majority of these serine hydrolases have not been described before. We studied transiently expressed SNG1 and investigated plants infected with the fungal pathogen Botrytis cinerea. Besides the down-regulation of several Arabidopsis Ser hydrolase activities during Botrytis infection, we detected the activities of Botrytis-derived cutinases and lipases, which are thought to contribute to pathogenicity. PMID:19136719

Kaschani, Farnusch; Gu, Christian; Niessen, Sherry; Hoover, Heather; Cravatt, Benjamin F.; van der Hoorn, Renier A. L.

2009-01-01

342

Cloning and sequencing of the major intracellular serine protease gene of Bacillus subtilis.  

PubMed Central

A Bacillus subtilis 2.7-kilobase DNA fragment containing an intracellular protease gene was cloned into Escherichia coli. The transformants produced an intracellular protease of approximately 35,000 Mr whose activity was inhibited by both phenylmethylsulfonyl fluoride and EDTA. Introduction of the fragment on a multicopy vector, pUB110, into B. subtilis caused a marked increase in the level of the intracellular protease. The nucleotide sequence of the cloned fragment showed the presence of an open reading frame for a possible proenzyme of the major intracellular serine protease (ISP-I) of B. subtilis with an NH2-terminal 17- or 20-amino-acid extension. The total amino acid sequence of the protease deduced from the nucleotide sequence showed considerable homology with that of an extracellular serine protease, subtilisin. The transcriptional initiation site of the ISP-I gene was identified by nuclease S1 mapping. No typical conserved sequence for promoters was found upstream of the open reading frame. An ISP-I-negative mutant of B. subtilis was constructed by integration of artificially deleted gene into the chromosome. The mutant sporulated normally in a nutritionally rich medium but showed decreased sporulation in a synthetic medium. The chloramphenicol resistance determinant of a plasmid integrated at the ISP-I locus was mapped by PBS1 transduction and was found to be closely linked to metC (99.5%). Images PMID:3087947

Koide, Y; Nakamura, A; Uozumi, T; Beppu, T

1986-01-01

343

Targeting class A and C serine ?-lactamases with a broad-spectrum boronic acid derivative.  

PubMed

Production of ?-lactamases (BLs) is the most widespread resistance mechanism adopted by bacteria to fight ?-lactam antibiotics. The substrate spectrum of BLs has become increasingly broad, posing a serious health problem. Thus, there is an urgent need for novel BL inhibitors. Boronic acid transition-state analogues are able to reverse the resistance conferred by class A and C BLs. We describe a boronic acid analogue possessing interesting and potent broad-spectrum activity vs class A and C serine-based BLs. Starting from benzo(b)thiophene-2-boronic acid (BZBTH2B), a nanomolar non-?-lactam inhibitor of AmpC that can potentiate the activity of a third-generation cephalosporin against AmpC-producing resistant bacteria, we designed a novel broad-spectrum nanomolar inhibitor of class A and C BLs. Structure-based drug design (SBDD), synthesis, enzymology data, and X-ray crystallography results are discussed. We clarified the inhibitor binding geometry responsible for broad-spectrum activity vs serine-active BLs using double mutant thermodynamic cycle studies. PMID:24882105

Tondi, Donatella; Venturelli, Alberto; Bonnet, Richard; Pozzi, Cecilia; Shoichet, Brian K; Costi, Maria Paola

2014-06-26

344

Age-dependent racemization of serine residues in a human chaperone protein.  

PubMed

Racemization is one of the most abundant modifications in long-lived proteins. It has been proposed that the accumulation of such modifications over time could lead to changes in tissues and ultimately human age-related diseases. Serine is one of the main amino acids involved in racemization; however, the site of D-Ser in any aged protein has yet to be reported. In this study, racemization of two residues, Ser 59 and Ser 62, has been demonstrated in an unstructured region of the small heat shock protein, ?A-crystallin. ?A-crystallin is also the most abundant structural protein in the human lens. D-Ser increased linearly with age in normal lenses, until it accounted for approximately 35% of the Ser at both sites by the age of 75 years. In agreement with a possible role in human age-related disease, levels were significantly higher in cataract lenses. It is likely that such prevalent age-related changes contribute to the denaturation of ?-crystallin, and therefore its ability to act as a chaperone. Racemization of amino acids, such as serine, in flexible regions of long-lived proteins, could be associated with the development of human age-related conditions such as cataract. PMID:23139182

Hooi, Michelle Y S; Raftery, Mark J; Truscott, Roger J W

2013-01-01

345

?Np63 transcriptionally regulates ATM to control p53 Serine-15 phosphorylation  

PubMed Central

Background ?Np63? is an epithelial progenitor cell marker that maintains epidermal stem cell self-renewal capacity. Previous studies revealed that UV-damage induced p53 phosphorylation is confined to ?Np63?-positive cells in the basal layer of human epithelium. Results We now report that phosphorylation of the p53 tumour suppressor is positively regulated by ?Np63? in immortalised human keratinocytes. ?Np63? depletion by RNAi reduces steady-state ATM mRNA and protein levels, and attenuates p53 Serine-15 phosphorylation. Conversely, ectopic expression of ?Np63? in p63-null tumour cells stimulates ATM transcription and p53 Serine-15 phosphorylation. We show that ATM is a direct ?Np63? transcriptional target and that the ?Np63? response element localizes to the ATM promoter CCAAT sequence. Structure-function analysis revealed that the ?Np63-specific TA2 transactivation domain mediates ATM transcription in coordination with the DNA binding and SAM domains. Conclusions Germline p63 point mutations are associated with a range of ectodermal developmental disorders, and targeted p63 deletion in the skin causes premature ageing. The ?Np63?-ATM-p53 damage-response pathway may therefore function in epithelial development, carcinogenesis and the ageing processes. PMID:20663147

2010-01-01

346

Azurocidin and a homologous serine protease from neutrophils. Differential antimicrobial and proteolytic properties.  

PubMed

Two 29-kD polypeptides, azurocidin and p29b, were purified to homogeneity from human neutrophils by acid extraction of azurophil granule membrane-associated material followed by gel filtration and reverse-phase chromatography. Azurocidin and p29b share NH2-terminal sequence homology with each other as well as with elastase, cathepsin G, and other serine proteases. p29b bound [3H]diisopropyl fluorophosphate and hydrolyzed elastin, casein, and hemoglobin. A peptide substrate for p29b could not be identified. Azurocidin neither bound [3H]diisopropyl fluorophosphate nor hydrolyzed any of the proteins, peptides, or esters tested. In microbicidal assays, purified azurocidin was comparable to p29b in activity against Escherichia coli, Streptococcus faecalis, and Candida albicans. The antimicrobial activity of azurocidin was enhanced under mildly acidic conditions, but was inhibited in a dose-dependent manner by NaCl, CaCl2, or serum. Immunoblot analysis with monospecific antibodies localized greater than 90% of the azurocidin and greater than 75% of the p29b to azurophil granule-rich fractions of PMN lysates. Immunoelectron microscopy confirmed the localization of azurocidin to the azurophil granules. Azurocidin associated with the azurophil granule membrane, but did not appear to be an integral membrane protein. Thus, azurocidin and p29b are members of a family of serine protease homologs stored in azurophil granules and may play a role in inflammatory and antimicrobial processes involving PMN. PMID:2312733

Campanelli, D; Detmers, P A; Nathan, C F; Gabay, J E

1990-03-01

347

Neu-Laxova Syndrome, an Inborn Error of Serine Metabolism, Is Caused by Mutations in PHGDH  

PubMed Central

Neu-Laxova syndrome (NLS) is a rare autosomal-recessive disorder characterized by severe fetal growth restriction, microcephaly, a distinct facial appearance, ichthyosis, skeletal anomalies, and perinatal lethality. The pathogenesis of NLS remains unclear despite extensive clinical and pathological phenotyping of the >70 affected individuals reported to date, emphasizing the need to identify the underlying genetic etiology, which remains unknown. In order to identify the cause of NLS, we conducted a positional-mapping study combining autozygosity mapping and whole-exome sequencing in three consanguineous families affected by NLS. Surprisingly, the NLS-associated locus identified in this study was solved at the gene level to reveal mutations in PHGDH, which is known to be mutated in individuals with microcephaly and developmental delay. PHGDH encodes the first enzyme in the phosphorylated pathway of de novo serine synthesis, and complete deficiency of its mouse ortholog recapitulates many of the key features of NLS. This study shows that NLS represents the extreme end of a known inborn error of serine metabolism and highlights the power of genomic sequencing in revealing the unsuspected allelic nature of apparently distinct clinical entities. PMID:24836451

Shaheen, Ranad; Rahbeeni, Zuhair; Alhashem, Amal; Faqeih, Eissa; Zhao, Qi; Xiong, Yong; Almoisheer, Agaadir; Al-Qattan, Sarah M.; Almadani, Halima A.; Al-Onazi, Noufa; Al-Baqawi, Badi S.; Saleh, Mohammad Ali; Alkuraya, Fowzan S.

2014-01-01

348

Characterization of a Novel Serine Protease Inhibitor Gene from a Marine Metagenome  

PubMed Central

A novel serine protease inhibitor (serpin) gene designated as Spi1C was cloned via the sequenced-based screening of a metagenomic library from uncultured marine microorganisms. The gene had an open reading frame of 642 base pairs, and encoded a 214-amino acid polypeptide with a predicted molecular mass of about 28.7 kDa. The deduced amino acid sequence comparison and phylogenetic analysis indicated that Spi1C and some partial proteinase inhibitor I4 serpins were closely related. Functional characterization demonstrated that the recombinant Spi1C protein could inhibit a series of serine proteases. The Spi1C protein exhibited inhibitory activity against ?-chymotrypsin and trypsin with Ki values of around 1.79 × 10?8 and 1.52 × 10?8 M, respectively. No inhibition activity was exhibited against elastase. Using H-d-Phe-Pip-Arg-pNA as the chromogenic substrate, the optimum pH and temperature of the inhibition activity against trypsin were 7.0–8.0 and 25 °C, respectively. The identification of a novel serpin gene underscores the potential of marine metagenome screening for novel biomolecules. PMID:22131953

Jiang, Cheng-Jian; Hao, Zhen-Yu; Zeng, Rong; Shen, Pei-Hong; Li, Jun-Fang; Wu, Bo

2011-01-01

349

Haploinsufficiency of cytosolic serine hydroxymethyltransferase in the Smith-Magenis syndrome  

SciTech Connect

Folate-dependent one-carbon metabolism is critical for the synthesis of numerous cellular constituents required for cell growth, and serine hydroxymethyltransferase (SHMT) is central to this process. Our studies reveal that the gene for cytosolic SHMT (cSHMT) maps to the critical interval for Smith-Magenis syndrome (SMS) on chromosome 17p11.2. The basic organization of the cSHMT locus on chromosome 17 was determined and was found to span{approximately}40 kb. The gene for cSHMT was found to be deleted in all 26 SMS patients examined by PCR, FISH, and/or Southern analysis. Furthermore, with respect to haploinsufficiency, cSHMT enzyme activity in patient lymphoblasts was determined to be {approximately}50% that of unaffected parent lymphoblasts. Serine, glycine, and folate levels were also assessed in three SMS patients and were found to be within normal ranges. The possible effects of cSHMT hemizygosity on the SMS phenotype are discussed. 40 refs., 3 figs., 21 tabs.

Elsea, S.H.; Juyal, R.C.; Jiralerspong, S. [Baylor College of Medicine, Houston, TX (United States)] [and others

1995-12-01

350

Crystal Structure of the Catalytic Domain of a Serine Threonine Protein Phosphatase  

NASA Technical Reports Server (NTRS)

Reversible phosphorylation of serine and threonine residues is a well-recognized mechanism in eukaryotic cells for the regulation of cell-cycle progression, cell growth and metabolism. Human serine/threonine phosphatases can be placed into two major families, PPP and PPM. To date the structure on one PPP family member (PPl) has been determined. Here we present the structure of a 323-residue catalytic domain of a second phosphatase belonging to the PPP family of enzyme. catalytic domain of the enzyme has been determined to 1.60Angstrom resolution and refined to R=17.5 and Rfree = 20.8%. The catalytic domain possesses a unique fold consisting of a largely monolithic structure, divisible into closely-associated helical and sheet regions. The catalytic site contains two manganese ions that are involved in substrate binding and catalysis. The enzyme crystallizes as a dimer that completely buries catalytic surfaces of both monomers, Also, the structure shows evidence of some flexibility around the active site cleft that may be related to substrate specificity of this enzyme.

Swinglel, Mark; Honkanel, Richard; Ciszak, Ewa

2003-01-01

351

Tryptogalinin Is a Tick Kunitz Serine Protease Inhibitor with a Unique Intrinsic Disorder  

PubMed Central

Background A salivary proteome-transcriptome project on the hard tick Ixodes scapularis revealed that Kunitz peptides are the most abundant salivary proteins. Ticks use Kunitz peptides (among other salivary proteins) to combat host defense mechanisms and to obtain a blood meal. Most of these Kunitz peptides, however, remain functionally uncharacterized, thus limiting our knowledge about their biochemical interactions. Results We discovered an unusual cysteine motif in a Kunitz peptide. This peptide inhibits several serine proteases with high affinity and was named tryptogalinin due to its high affinity for ?-tryptase. Compared with other functionally described peptides from the Acari subclass, we showed that tryptogalinin is phylogenetically related to a Kunitz peptide from Rhipicephalus appendiculatus, also reported to have a high affinity for ?-tryptase. Using homology-based modeling (and other protein prediction programs) we were able to model and explain the multifaceted function of tryptogalinin. The N-terminus of the modeled tryptogalinin is detached from the rest of the peptide and exhibits intrinsic disorder allowing an increased flexibility for its high affinity with its inhibiting partners (i.e., serine proteases). Conclusions By incorporating experimental and computational methods our data not only describes the function of a Kunitz peptide from Ixodes scapularis, but also allows us to hypothesize about the molecular basis of this function at the atomic level. PMID:23658744

Valdés, James J.; Schwarz, Alexandra; Cabeza de Vaca, Israel; Calvo, Eric; Pedra, Joao H. F.

2013-01-01

352

Kinetics of action of a two-stage pro-inhibitor of serine ?-lactamases.  

PubMed

?-Lactamase inhibitors are important in medicine in the protection of ?-lactam antibiotics from ?-lactamase-catalyzed destruction. The most effective inhibitors of serine ?-lactamases covalently modify the enzyme active site. We have recently studied O-acyl and O-phosphyl hydroxamates as a new class of such inhibitors. In this paper, we describe our studies of the N-acyl derivatives of a cyclic O-acyl hydroxamic acid, 3H-benzo[d][1,2]oxazine-1,4-dione, and, in particular, the N-tert-butoxycarbonyl derivative. This compound is not a ?-lactamase inhibitor itself but undergoes spontaneous hydrolysis in aqueous solution, yielding an O-phthaloyl hydroxamic acid, which is a ?-lactamase inhibitor. This compound spontaneously, but reversibly, cyclizes in solution to form phthalic anhydride, which is also a ?-lactamase inhibitor. Both inhibitors react to form the same transiently stable phthaloyl-enzyme complex. Thus, we have a two-step cascade, beginning with a pro-inhibitor, in which each step leads to a different inhibitor, presumably with different enzyme specificities. The kinetics of these transformations have been elucidated in detail. The phthaloyl derivatives, where the free carboxylate is important for facile reaction with the enzyme, represent a new lead for serine ?-lactamase inhibitors. Analogues can be conveniently constructed in situ by reaction of nucleophiles with phthalic anhydrides and then screened for activity. Active hits may then become new leads. PMID:24070199

Tilvawala, Ronak; Pratt, R F

2013-10-01

353

pKa optimized catalysis in serine proteinases, an ab initio study on the catalaytic His  

NASA Astrophysics Data System (ADS)

First principle models of catalytic apparatus of enzymes can be used for studying stability as well as the atomic details of a catalytic mechanism. For example, the catalytic triad of chymotrypsin was recently investigated by using an ab initio geometry optimized (Hudáky and Perczel, Proteins: Struct Funct Genet, 2006, 62, 749) self-stabilizing molecule ensemble without the presence of the complete enzyme and substrate. Several parameters of the above catalytic reaction turned out to be the same within the model and the in vitro enzymatic reaction. Among the numerous parameters of the catalytic process geometrical changes of the catalytic histidine was investigated here and the variation of its pKa value was determined. A relatively large range, 3.5 unit, was determined as the variation of pKa as function of the conformational subspace available in serine proteases. Comparing PDB structures of the free and the complex enzymes it was shown, that histidine, after accepting the proton from the OH group of the catalytic serine, undergoes a minor conformational change accompanied by a 2.5 unit decrease in pKa. We conclude that the changes of pKa during catalysis are predominantly determined by the geometrical arrangement of the histidine moiety and this change serves as a significant driving force in the catalytic process.0

Hudáky, Péter; Perczel, András

354

Inhibition of serine proteases of the blood coagulation system by squash family protease inhibitors.  

PubMed

Squash family inhibitors are the smallest protein serine protease inhibitors, being composed of approximately 30 amino acid residues. We isolated 8 squash family inhibitors from the seeds of bitter gourd, squash, gourd and luffa and examined their effect on serine proteases of the blood coagulation system. Five of them prolonged the activated partial thromboplastin time of human plasma to various extents, but three did not. Only Momordica charantia (bitter gourd) trypsin inhibitor-II prolonged the prothrombin time of human plasma. All inhibitors inhibited the amidolytic activities of factor XIIa, plasma kallikrein, factor Xa, but did not inhibit significantly those of factor XIa, factor IXa, factor VIIa, and thrombin. Ki values for factor XIIa, plasma kallikrein, and factor Xa were in the order of 10(-6)-10(-9), 10(-4)-10(-5), and 10(-4)-10(-6)M, respectively. The prolongation of the activated partial thromboplastin time by inhibitors appeared to correspond to their inhibitory potencies for factor XIIa. Momordica charantia trypsin inhibitor-II, which has the strongest inhibitory potency toward the amidolytic activity of factor Xa, with a Ki value 10-100 times smaller than those of other inhibitors, inhibited the activation of factor X by factor VIIa-tissue factor complex or factor IXa, while others did not. PMID:7896727

Hayashi, K; Takehisa, T; Hamato, N; Takano, R; Hara, S; Miyata, T; Kato, H

1994-11-01

355

Staphylococcus aureus secretes a unique class of neutrophil serine protease inhibitors  

PubMed Central

Neutrophils are indispensable for clearing infections with the prominent human pathogen Staphylococcus aureus. Here, we report that S. aureus secretes a family of proteins that potently inhibits the activity of neutrophil serine proteases (NSPs): neutrophil elastase (NE), proteinase 3, and cathepsin G. The NSPs, but not related serine proteases, are specifically blocked by the extracellular adherence protein (Eap) and the functionally orphan Eap homologs EapH1 and EapH2, with inhibitory-constant values in the low-nanomolar range. Eap proteins are together essential for NSP inhibition by S. aureus in vitro and promote staphylococcal infection in vivo. The crystal structure of the EapH1/NE complex showed that Eap molecules constitute a unique class of noncovalent protease inhibitors that occlude the catalytic cleft of NSPs. These findings increase our insights into the complex pathogenesis of S. aureus infections and create opportunities to design novel treatment strategies for inflammatory conditions related to excessive NSP activity. PMID:25161283

Stapels, Daphne A. C.; Ramyar, Kasra X.; Bischoff, Markus; von Köckritz-Blickwede, Maren; Milder, Fin J.; Ruyken, Maartje; Eisenbeis, Janina; McWhorter, William J.; Herrmann, Mathias; van Kessel, Kok P. M.; Geisbrecht, Brian V.; Rooijakkers, Suzan H. M.

2014-01-01

356

TIANJIN SUBURBS PS-QPS ANALYSIS AND VALIDATION WITH LEVELING DATA  

E-print Network

subsidence at a low cost. Classical PS algorithms are focused on exploring the point-like radar targets while with the control of strict rules. However, with the development of rural economy and lack of supervision, several]. Classical PS algorithms that focus on exploring the point- like radar targets cannot achieve sufficient

Perissin, Daniele

357

Phytophthora sojae Effector PsCRN70 Suppresses Plant Defenses in Nicotiana benthamiana  

PubMed Central

Phytophthora sojae, an oomycete pathogen, produces a large number of effector proteins that enter into host cells. The Crinklers (Crinkling and Necrosis, CRN) are cytoplasmic effectors that are conserved in oomycete pathogens and their encoding genes are highly expressed at the infective stages in P. sojae. However, their roles in pathogenesis are largely unknown. Here, we functionally characterized an effector PsCRN70 by transiently and stably overexpressing it in Nicotiana benthamiana. We demonstrated that PsCRN70 was localized to the plant cell nucleus and suppressed cell death elicited by all the tested cell death-inducing proteins, including BAX, PsAvh241, PsCRN63, PsojNIP and R3a/Avr3a. Overexpression of the PsCRN70 gene in N. benthamiana enhanced susceptibility to P. parasitica. The H2O2 accumulation in the PsCRN70-transgenic plants was reduced compared to the GFP-lines. The transcriptional levels of the defense-associated genes, including PR1b, PR2b, ERF1 and LOX, were also down-regulated in the PsCRN70-transgenic lines. Our results suggest that PsCRN70 may function as a universal suppressor of the cell death induced by many elicitors, the host H2O2 accumulation and the expression of defense-associated genes, and therefore promotes pathogen infection. PMID:24858571

Ru, Yanyan; Liu, Tingli; Xu, Jing; Liu, Li; Mafurah, Joseph Juma; Dou, Daolong

2014-01-01

358

Proposed Policy Statement Number: PS-67 Title/Topic: Misuse of Drugs or Alcohol  

E-print Network

603094.2 Proposed Policy Statement Number: PS-67 Title/Topic: Misuse of Drugs or Alcohol Effective Date: 01/07/2013 Revision Number: PS0067.R05 MISUSE OF DRUGS OR ALCOHOL Louisiana State University of the University. Although the University respects an employee's right to privacy, the misuse of drugs or alcohol

Harms, Kyle E.

359

Multimedia Authoring for CoPs Romain Deltour, Agn`es Guerraz, and Cecile Roisin  

E-print Network

Multimedia Authoring for CoPs Romain Deltour, Agn`es Guerraz, and C´ecile Roisin INRIA Rh is to build multimedia authoring and publishing tools that meets CoPs requirements. In this paper we analyze these requirements and propose a multimedia authoring model and a generic platform on which specific Co

Paris-Sud XI, Université de

360

J. Mol. Biol. (1992) 226, 239-250 A 500 ps Molecular Dynamics Simulation Study of  

E-print Network

J. Mol. Biol. (1992) 226, 239-250 A 500 ps Molecular Dynamics Simulation Study of Interleukin the results of a 500 ps molecular dynamics simulation of the cytokine interleukin-lb, a protein of 153 amino bonds. Keywords: interleukin 1s; molecular dynamics simulation; n.m.r. relaxation; X-ray B-factors 1

Clore, G. Marius

361

Role of propagating ionisation fronts in semiconductor generation of sub-ps THz radiation  

E-print Network

Role of propagating ionisation fronts in semiconductor generation of sub-ps THz radiation S, United Kingdom Abstract Observations of a directional asymmetry in the sub-ps THz radiation generated incorporated through sub-surface diffusion dynamics, and through consideration of a non-tangential current

Strathclyde, University of

362

Checking Integrity via CoPS and Banana: the E-Commerce Case Study  

E-print Network

Checking Integrity via CoPS and Banana: the E-Commerce Case Study Chiara Braghin1 and Carla Piazza2 be modeled and its integrity verified using the two techniques. The tools CoPS and Banana are used to perform

Piazza, Carla

363

Elastomeric Capture Microparticles (ECmuPs) and Their use with Acoustophoresis to Perform Affinity Capture Assays  

NASA Astrophysics Data System (ADS)

This dissertation describes the development of elastomeric capture microparticles (ECmicroPs) and their use with acoustophoresis to perform affinity capture assays. EC?Ps that function as negative acoustic contrast particles were developed by crosslinking emulsion-based droplets composed of commercially available silicone precursors followed by functionalization with avidin/biotin reagents. The size distribution of the EC?Ps was very broad or narrow depending on the emulsion system that was used during the synthesis process. Elastomeric particles exhibited a very broad size distribution when a bulk-emulsion process was used; however, when microfluidic systems were utilized, their size distribution became comparatively narrow. The functionalization of elastomeric particles was accomplished by the non-specific adsorption of avidin protein followed by bovine serum albumin (BSA) blocking and bio-specific adsorption of a biotinylated-capture antibody. Polydisperse EC?Ps were functionalized to bind prostate specific antigen (PSA) or IgG-phycoerythrin (PE) in aqueous media (buffer, plasma, blood); whereas monodisperse EC?Ps were functionalized to bind a high density lipoprotein in the aqueous media. Polydisperse EC?Ps functionalized to bind PSA in a physiological buffer (PBS pH 7.4) demonstrated nanomolar detection using flow cytometry analysis; whereas EC?Ps functionalized to bind IgG-PE demonstrated picomolar detection in 10% porcine plasma. EC?Ps have a specific density of ~1.03 and are more compressible than their surrounding aqueous media; which allowed the EC?Ps to exhibit negative acoustic contrast properties under an ultrasonic acoustic standing wave field. The negative acoustic contrast property of EC?Ps was advantageously utilized in an IgG-PE assay conducted in 0.1% whole porcine blood. The ligand-bound EC?Ps suspended in the diluted blood sample were flowed through an acoustofluidic device where the application of an ultrasonic acoustic standing wave field focused the ligand-bound EC?Ps to pressure antinodes and the positive acoustic contrast blood cells to the central pressure node of the microchannel. As a result of laminar flow, focused ligand-bound EC?Ps and blood cells were flowed into properly aligned outlet channels at the downstream trifurcation, where they where collected separately off-chip. The cell-free fraction containing ligand-bound EC?Ps was analyzed using flow cytometry; where the detection of IgG-PE was in the picomolar range. This approach has potential applications in the development of rapid assays that detect the presence of low concentrations of biomarkers in a number of biological sample types.

Cushing, Kevin Wallace

364

Study of white light emission from ZnS/PS composite system  

NASA Astrophysics Data System (ADS)

ZnS films were deposited by pulsed laser deposition (PLD) on porous silicon (PS) substrates formed by electrochemical anodization of p-type (100) silicon wafer. The photoluminescence (PL) spectra of ZnS/PS composites were measured at room temperature. Under different excitation wavelengths, the relative integrated intensities of the red light emission from PS layers and the blue-green emission from ZnS films had different values. After samples were annealed in vacuum at different temperatures (200, 300, and 400 Celsius degree) for 30 min respectively, a new green emission located at around 550 nm appeared in the PL spectra of all ZnS/PS samples, and all of the ZnS/PS composites had a broad PL band (450-700 nm) in the visible region, exhibiting intensively white light emission.

Wang, Caifeng; Li, Qingshan; Lu, Lei; Zhang, Lichun; Qi, Hongxia

2007-09-01

365

Differentiation stage determines reprogramming potential of hematopoietic cells into iPS cells  

PubMed Central

The reprogramming of somatic cells into induced pluripotent stem (iPS) cells upon overexpression of the transcription factors Oct4, Sox2, Klf4 and cMyc is extremely inefficient. It has been assumed that the somatic differentiation state provides a barrier for efficient reprogramming; however, direct evidence for this notion is lacking. Here, we have tested the susceptibilities of hematopoietic cells at different stages of differentiation to be reprogrammed into iPS cells. Surprisingly, hematopoietic stem and progenitor cells give rise to iPS cells up to 300 times more efficiently compared with terminally differentiated B and T cells, yielding reprogramming efficiencies of up to 28%. Our data provide evidence that the differentiation stage of the starting cell has a critical influence on the efficiency of reprogramming into iPS cells. Moreover, we identify adult hematopoietic progenitors as an attractive cell type for applications of iPS technology in research and therapy. PMID:19668214

Eminli, Sarah; Foudi, Adlen; Stadtfeld, Matthias; Maherali, Nimet; Ahfeldt, Tim; Mostoslavsky, Gustavo; Hock, Hanno; Hochedlinger, Konrad

2013-01-01

366

Tribology and Microstructure of PS212 with a Cr2O3 Seal Coat  

NASA Technical Reports Server (NTRS)

PS212 is a plasma sprayed metal bonding chrome carbide coating with solid lubricant additives which has lubricating properties at temperatures up to about 900 deg C. The coating is diamond ground to achieve an acceptable tribological surface. But, as with many plasma spray coatings, PS212 is not fully-dense. In this study, a chromium oxide base seal coating is used in an attempt to seal any porosity that is open to the surface of the PS212 coating, and to study the effect of the sealant on the tribological properties of PS212. The results indicate that the seal coating reduces friction and wear when it is applied and then diamond ground leaving a thin layer of seal coating which fills in the surface pits of the PS212 coating.

Sliney, Harold E.; Benoy, Patricia A.; Korenyi-Both, Andras; Dellacorte, Christopher

1994-01-01

367

Utilization of glycine and serine as nitrogen sources in the roots of Zea mays and Chamaegigas intrepidus.  

PubMed

Glycine and serine are potential sources of nitrogen for the aquatic resurrection plant Chamaegigas intrepidus Dinter in the rock pools that provide its natural habitat. The pathways by which these amino acids might be utilized were investigated by incubating C. intrepidus roots and maize (Zea mays) root tips with [(15)N]glycine, [(15)N]serine and [2-(13)C]glycine. The metabolic fate of the label was followed using in vivo NMR spectroscopy, and the results were consistent with the involvement of the glycine decarboxylase complex (GDC) and serine hydroxymethyltransferase (SHMT) in the utilization of glycine. In contrast, the labelling patterns provided no evidence for the involvement of serine:glyoxylate aminotransferase in the metabolism of glycine by the root tissues. The key observations were: (i) the release of [(15)N]ammonium during [(15)N]-labelling experiments; and (ii) the detection of a characteristic set of serine isotopomers in the [2-(13)C]glycine experiments. The effects of aminoacetonitrile, amino-oxyacetate, and isonicotinic acid hydrazide, all of which inhibit GDC and SHMT to some extent, and of methionine sulphoximine, which inhibited the reassimilation of the ammonium, supported the conclusion that GDC and SHMT were essential for the metabolism of glycine. C. intrepidus was observed to metabolize serine more readily than the maize root tips and this may be an adaptation to its nitrogen-deficient habitat. Overall, the results support the emerging view that GDC is an essential component of glycine catabolism in non-photosynthetic tissues. PMID:12432023

Hartung, W; Ratcliffe, R G

2002-12-01

368

Pharmacological PPAR? Activation Markedly Alters Plasma Turnover of the Amino Acids Glycine, Serine and Arginine in the Rat  

PubMed Central

The current study extends previously reported PPAR? agonist WY 14,643 (30 µmol/kg/day for 4 weeks) effects on circulating amino acid concentrations in rats fed a 48% saturated fat diet. Steady-state tracer experiments were used to examine in vivo kinetic mechanisms underlying altered plasma serine, glycine and arginine levels. Urinary urea and creatinine excretion were measured to assess whole-body amino acid catabolism. WY 14,643 treated animals demonstrated reduced efficiency to convert food consumed to body weight gain while liver weight was increased compared to controls. WY 14,643 raised total amino acid concentration (38%), largely explained by glycine, serine and threonine increases. 3H-glycine, 14C-serine and 14C-arginine tracer studies revealed elevated rates of appearance (Ra) for glycine (45.5±5.8 versus 17.4±2.7 µmol/kg/min) and serine (21.0±1.4 versus 12.0±1.0) in WY 14,643 versus control. Arginine was substantially decreased (?62%) in plasma with estimated Ra reduced from 3.1±0.3 to 1.2±0.2 µmol/kg/min in control versus WY 14,643. Nitrogen excretion over 24 hours was unaltered. Hepatic arginase activity was substantially decreased by WY 14,643 treatment. In conclusion, PPAR? agonism potently alters metabolism of several specific amino acids in the rat. The changes in circulating levels of serine, glycine and arginine reflected altered fluxes into the plasma rather than changes in clearance or catabolism. This suggests that PPAR? has an important role in modulating serine, glycine and arginine de novo synthesis. PMID:25486018

Ericsson, Anette; Turner, Nigel; Hansson, Göran I.; Wallenius, Kristina; Oakes, Nicholas D.

2014-01-01

369

Serine hydrolase organophosphate interactions: Molecular modeling. Final report, 15 June 1991-31 December 1994  

SciTech Connect

The aging reaction from the adducts of electric eel (EE) and fetal bovine serum (FBS) acetyicholinesterase (AChE) with soman P(-)C(-) and P(-)C(+) show a bell-shaped pH-rate profile. The aging of soman and sarin are specific acid catalyzed and show small (1.1 - 1.6) solvent isotope effects. These results and molecular mechanics calculations support the push-pull mechanism by Glu199 and the H-bonding array of the oxyanion hole in AChE. Semi-empirical calculations for ten phosphonate derivatives gave optimal results with the MNDO Hamiltonian. MNDO was also used for the generation of optimal - geometries and charges for phosphonate esters of Ser- 195 fragments from AChE. Full refinements were performed using program YETI with the fully solvated native Torpedo califomica - AChE, trypsin and chymotrypsm and their adducts with monoisopropyl and diisopropyl phosphate (trypsin only) diastereomers of 2-propyl methylphosphonate, pinacolyl methylphosphonate and their dealkylation products. The P(R) adducts of soman-inhibited AChE are 17-26 kcal/mol less stable than the Ps adduct. The P(R) 2-propyl methyiphosphonyl adduct of trypsin is less stable than the Ps isomer by 2 kcallmol and the product of dealkylation of the Ps is more stable by 3.7 kcal/mol.

Kovach, I.M.

1995-02-03

370

Analysis of L-serine-O-phosphate in cerebrospinal spinal fluid by derivatization-liquid chromatography/mass spectrometry.  

PubMed

L-serine-O-phosphate (L-SOP), the precursor of L-serine, is a potent agonist against the group III metabotropic glutamate receptors (mGluRs) and, thus, is of interest as a potential biomarker for monitoring modulation of neurotransmitter release. So far, no reports are available on the analysis of L-SOP in cerebrospinal fluid (CSF). Here a novel method is presented to determine L-SOP levels in CSF employing precolumn derivatization with (5-N-succinimidoxy-5-oxopentyl)triphenylphosphonium bromide (SPTPP) coupled to liquid chromatography/mass spectrometry (derivatization-LC/MS, d-LC/MS). PMID:24534252

McNaney, Colleen A; Benitex, Yulia; Luchetti, David; Labasi, Jeffrey M; Olah, Timothy V; Morgan, Daniel G; Drexler, Dieter M

2014-05-01

371

PP and PS joint AVO inversion and fluid prediction  

NASA Astrophysics Data System (ADS)

The technique of amplitude variation with offset or angle (AVO or AVA) can be used to extract fluid and lithology information from prestack seismic data. Based on three-term AVO equations, three elastic parameters can be inverted for by linear AVO inversion. However, many theoretical and numerical studies have demonstrated that by using offset limited data, a three-term AVO inversion may have problems of instability and inaccuracy while inverting for the density term. We have searched for an elastic parameter that contains density information and inverted this parameter in a more stable manner using offset limited data. First, we test the sensitivity of elastic parameters to hydrocarbon reservoirs and select the optimal fluid factor (?f) that contains density information and has an excellent performance as an inversion parameter used to detect hydrocarbons. Then, we derive approximate PP and PS reflection coefficient equations in terms of the fluid factor. The derived equations allow us to directly estimate the fluid factor of the reservoir. Finally, we apply these equations to synthetic data by employing a joint AVO inversion technique. The results show that the method is stable and unambiguous.

Du, Qizhen; Yan, Huizhong

2013-03-01

372

A Critical Appraisal of NLO+PS Matching Methods  

SciTech Connect

In this publication, uncertainties in and differences between the MC{at}NLO and POWHEG methods for matching next-to-leading order QCD calculations with parton showers are discussed. Implementations of both algorithms within the event generator SHERPA are employed to assess the impact on a representative selection of observables. In the MC{at}NLO approach a phase space restriction has been added to subtraction and parton shower, which allows to vary in a transparent way the amount of non-singular radiative corrections that are exponentiated. Effects on various observables are investigated, using the production of a Higgs boson in gluon fusion, with or without an associated jet, as a benchmark process. The case of H+jet production is presented for the first time in an NLO+PS matched simulation. Uncertainties due to scale choices and non-perturbative effects are explored in the production of W{sup {+-}} and Z bosons in association with a jet. Corresponding results are compared to data from the Tevatron and LHC experiments.

Hoeche, Stefan; /SLAC; Krauss, Frank; Schonherr, Marek; /Durham U., IPPP; Siegert, Frank; /Freiburg U.

2012-03-19

373

Revisiting the Surface Properties of PS/PVME Blends  

NASA Astrophysics Data System (ADS)

The generalized Van der Waals square gradient theory as embodied in the development of Schmidt and Binder is applied to model the surface properties of miscible blends of polystyrene (PS) and polyvinyl methyl ether (PVME). X-ray photoelectron spectroscopy data reveals the preferential surface adsoprtion of the lower surface energy PVME. To apply the theory, both the Flory-Huggins and Sanchez-Lacombe-Balazs equations of state are utilized to represent the free energy curves. The latter EOS gives excellent representations of experimental cloud point behavior. The models of surface behavior give good predictions of surface compositions only for blends with PVME compositions greater than about 50the predictions from experimental data for lower concentrations have two possible origins: the bulk interaction parameter at the surface, where there is a density gradient, may differ from that of the normal bulk region, or PVME chains adsobed at the surface for low concentration blends may be stretched. These possible explanations are discussed in light of the data.

Koberstein, Jeff; Chris, Forrey

2001-03-01

374

570-ps 13-m W Josephson 1-kbit NDRO RAM  

SciTech Connect

This paper reports Josephson 1-kbit random access memories (RAM's) fabricated using Nb multilayer planarization technology with Nb/AlO{sub {ital x}}/Nb junctions and Mo resistors. The RAM design has been reported previously. The RAM consists of a 32 {times} 32-bit nondestructive readout (NDRO) memory cell array and peripheral circuits. The NDRO memory cell consists of a loop storing three flux quanta and two 3-junction interferometer gates. The peripheral circuits consist of decoders with address inverters, drivers, a sense circuit, and reset circuits, where resistor-coupled Josephson logic (RCJL) circuits are used as basic circuits. The RAM circuit size is 4.4 {times} 4.4 mm{sup 2}, and the memory cell size is 65 {times} 65 {mu}m{sup 2}. About 10000 Nb/AlO{sub {ital x}}/Nb junctions with 1030-A/cm{sup 2} critical current density were contained in the RAM. Minimum line and space widths were 3 and 2 {mu}m, respectively. The Mo resistors had 1.2 {approximately} 1.3 {Omega} sheet resistance. ABout 40 percent of the bits were successfully operated with a {+-} 18-percent bias margin. A minimum 570-ps access time with 13-mW power dissipation was obtained for the highest peripheral circuit bias conditions.

Nagasawa, S.; Wada, Y.; Hidaka, M.; Tsuge, H.; Ishida, I.; Tahara, S. (Microelectronics Research Labs., NEC Corp., Ibaraki (JP))

1989-10-01

375

Fragmentation of Positronium (Ps) in collision with Li ion  

E-print Network

Fragmentation of ground state ortho Positronium (Ps) in collision with Li ion (Li+) is studied in the framework of post collisional Coulomb distorted eikonal approximation (CDEA) for the target elastic case . The present model takes account of the two center effect on the ejected e which is crucial for a proper description of the projectile ionization involving an ionic target. Both the fully differential (TDCS) and the doubly differential (DDCS) cross sections (energy spectra) are investigated at intermediate and high incident energies. A broad distinct Electron loss peak (ELP) centered around v_e ~ v_p is noted in the e energy spectrum in contrast to the sharp ELP for a heavy projectile. Two salient features are noted in the present study: i) the shift of the e DDCS peak (summed over e+ angles) towards higher ejection energy with respect to half the residual energy of the system, ii) comparison of the e& e+ energy spectra reflect a strong e - e+ asymmetry with respect to the ratio v_e/v_p =1 >. Both the...

Roy, S

2008-01-01

376

Dynamics of ps-pulse induced gratings in LC panels  

NASA Astrophysics Data System (ADS)

In the present work we focused our attention on studies of PVK:TNF hybrid polymer liquid crystal panels under short pulse laser illumination conditions. The diffraction gratings in a LC panel were induced by crossed beams generated by doubled in frequency Nd:YAG laser ((lambda) equals 532 nm) delivering pulses of 20 ps duration. So induced gratings were read by a cw laser radiation coming from a weak power He-Ne laser working at (lambda) equals 632.8 nm. The temporal evolution of intensity of first order diffraction measured in PVK:TNF hybrid liquid crystal panels shows many interesting features and complexity dependent on various experimental conditions. The substantial diffraction is observed already in time less than 1 ms after the pulse and the grating decay is completed within hundreds of milliseconds. At least three different steps of grating build-up can be distinguished which depend in various ways on the experimental conditions. A tentative mechanism of the observed responses is discussed in connection with the photoconductive properties of polymeric layers and the optical and electrical properties of the used liquid crystal E-7 (Merck).

Bartkiewicz, Stanislaw; Miniewicz, Andrzej; Sahraoui, Bouchta; Kajzar, Francois

2002-06-01

377

Preliminary evaluation of PS300: A new self-lubricating high temperature composite coating for use to 800 C  

SciTech Connect

This paper introduces PS300, a plasma sprayed, self-lubricating composite coating for use in sliding contacts at temperatures to 800 C. PS300 is a metal bonded chrome oxide coating with silver and BaF{sub 2}/CaF{sub 2} eutectic solid lubricant additives. PS300 is similar to PS200, a chromium carbide based coating; which is currently being investigated for a variety of tribological applications. In pin-on-disk testing up to 650 C, PS300 exhibited comparable friction and wear properties to PS200. The PS300 matrix, which is predominantly chromium oxide rather than chromium carbide, does not require diamond grinding and polishes readily with silicon carbide abrasives greatly reducing manufacturing costs compared to PS200.

DellaCorte, C.; Edmonds, B.J. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

1996-11-01

378

Serine Protease Inhibitor Attenuates Ovalbumin Induced Inflammation in Mouse Model of Allergic Airway Disease  

PubMed Central

Background Serine proteases promote inflammation and tissue remodeling by activating proteinase-activated receptors, urokinase, metalloproteinases and angiotensin. In the present study, 4-(2-Aminoethyl) benzenesulfonyl fluoride (AEBSF) a serine protease inhibitor was evaluated for prophylactic and therapeutic treatment in mouse model of airway allergy. Methods BALB/c mice were sensitized by i.p route and challenged with ovalbumin. They were treated i.n. with 2, 10 and 50 µg of AEBSF, one hour before or after challenge and euthanized to collect BALF (bronchoalveolar lavage fluid), blood and lungs. Proteolytic activity, total cell/eosinophil/neutrophil count eosinophil peroxidase activity (EPO), IL-4, IL-5, IL-10, IL-13, cysteinyl leukotrienes and 8-isoprostane were determined in BALF and immunoglobulins were measured in serum. H&E and PAS stained lung sections were examined for cellular infiltration and airway inflammation. Results Mice exposed to ovalbumin and treated with PBS showed increased cellular infiltration in lungs and higher serum IgE, IgG1 and IgG2a levels as compared to sham mice. Treatment with AEBSF reduced total cells/eosinophil/neutrophil infiltration. Both prophylactic and therapeutic AEBSF treatment of 10 or 50 µg reduced serum IgE and IgG1 significantly (p<0.05) than control. AEBSF treatment reduced the proteolytic activity in BALF. IL-4 IL-5 and IL-13 levels decreased significantly (p<0.05) after AEBSF treatment while IL-10 levels increased significantly (p<0.05) in BALF. Airway inflammation and goblet cell hyperplasia reduced as demonstrated by lung histopathology, EPO activity and cysteinyl leukotrienes in BALF after treatment. AEBSF treatment also suppressed oxidative stress in terms of 8-isoprostane in BALF. Among the treatment doses, 10 or 50 µg of AEBSF were most effective in reducing the inflammatory parameters. Conclusions Prophylactic and therapeutic treatment with serine protease inhibitor attenuates the airway inflammation in mouse model of airway allergy and have potential for adjunct therapy. PMID:22829914

Saw, Sanjay; Kale, Sagar Laxman; Arora, Naveen

2012-01-01

379

ARABIDOPSIS PLANTS WITH AN INDUCED RNAI HAIRPIN OR A CONSTITUTIVELY EXPRESSED DOMINANT-NEGATIVE ALLELE OF THE SERINE PALMITOYLTRANSFERASE LCB2 GENE HAVE ALTERED SPHINGOLIPID CONTENT AND DEVELOPMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

The first step in sphingolipid biosynthesis is the condensation of palmitoyl-CoA and serine to form 3-ketosphinganine. This reaction is catalyzed by serine palmitoyltransferase (SPT), a pyridoxal 5’ phosphate-dependent enzyme. In yeast, SPT is a heterodimer that consists of the polypeptides LCB1 and...

380

Synthesis of Water-Soluble Poly(-hydroxy acids) from Living Ring-Opening Polymerization of O-Benzyl-L-serine Carboxyanhydrides  

E-print Network

Synthesis of Water-Soluble Poly(-hydroxy acids) from Living Ring-Opening Polymerization of O syn- thesized via diazotization of O-benzyl-L-serine with sodium nitrite in sulfuric acid aqueous solution followed by cyclization of the resulting serine-based -hydroxy acid with phosgene. Degradable

Cheng, Jianjun

381

Endophytic Colonization of Vitis vinifera L. by Plant Growth-Promoting Bacterium Burkholderia sp. Strain PsJN  

Microsoft Academic Search

Patterns of colonization of Vitis vinifera L. cv. Chardonnay plantlets by a plant growth-promoting bacterium, Burkholderia sp. strain PsJN, were studied under gnotobiotic conditions. Wild-type strain PsJN and genetically engineered derivatives of this strain tagged with gfp (PsJN::gfp2x) or gusA (PsJN::gusA11) genes were used to enumerate and visualize tissue colonization. The rhizospheres of 4- to 5-week-old plantlets with five developed

Stephane Compant; Birgit Reiter; Angela Sessitsch; Jerzy Nowak; Christophe Clement; E. Ait Barka

2005-01-01

382

1.2-ps mode-locked semiconductor optical amplifier fiber laser pulses generated by 60-ps backward dark-optical comb injection and soliton compression.  

PubMed

Optically harmonic mode-locking of a semiconductor optical amplifier fiber laser (SOAFL) induced by backward injecting a dark-optical comb is demonstrated for the first time. The dark-optical comb with 60-ps pulsewidth is generated from a Mach-Zehnder modulator, which is driven by an electrical comb at a DC offset of 0.3Vn. Theoretical simulation indicates that the backward injection of dark-optical comb results in a narrow gain window of 60 ps within one modulating period, providing a cross-gainmodulation induced mode-locking in the SOAFL with a shortest pulsewidth of 15 ps at repetition frequency of 1 GHz. The mode-locked SOAFL pulsewidth can be slightly shortened to 10.8 ps with a 200m-long dispersion compensating fiber. After nonlinearly soliton compression in a 5km-long single mode fiber, the pulsewidth, linewidth and time-bandwidth product become 1.2 ps, 2.06 nm and 0.31, respectively. PMID:19494964

Lin, Gong-Ru; Chiu, I-Hsiang; Wu, Ming-Chung

2005-02-01

383

Conversion of the PS Complex as LHC Proton Pre-Injector  

NASA Astrophysics Data System (ADS)

SCERN's Large Hadron Collider (LHC) will be supplied with protons from the injector chain Linac2-PSB-PS-SPS. The required transverse beam brilliance (intensity/emittance) is about twice that of current PS beams and the LHC bunch spacing of 25 ns must be impressed on the beam before its transfer to the SPS. The scheme involves new RF harmonics in the PSB and PS, an increase of the PSB energy from 1 GeV to 1.4 GeV, and two-batch filling of the PS. After a successful test of the main ingredients, the project for converting the PS complex was launched in 1994. Major additions are (i) h=1 RF systems in the PSB, (ii) 40 and 80 MHz fixed-frequency systems in the PS, (iii) upgrading of the PSB main magnet supply to 1.4 GeV operation, (iv) new magnets, septa, power supplies, as well as kicker pulsers for the PSB-PS beam transfer, and (v) beam profile measurement devices of improved resolution. A significant part of the effort is being provided by TRIUMF under the Canada-CERN co-operation agreement on LHC. The project, its status, and recent test results are presented.

Schindl, K.; Cappi, R.; Chohan, V.; Cornuet, D.; Daems, G.; Dekkers, D.; Garoby, R.; Grier, D.; Gruber, J.; Jensen, E.; Koziol, H.; Krusche, A.; Metzmacher, K. D.; Pedersen, J.; Pedersen, F.; Raich, U.; Riunaud, J. P.; Royer, J. P.; Sassowsky, M.; Schönauer, H.; Thivent, M.; Ullrich, H.; Völker, F.

1997-05-01

384

Accurate theoretical study of PS(q) (q = 0,+1,-1) in the gas phase.  

PubMed

Highly correlated ab initio methods were used in order to generate the potential energy curves and spin-orbit couplings of electronic ground and excited states of PS and PS(+). We also computed those of the bound parts of the electronic states of the PS(-) anion. We used standard coupled cluster CCSD(T) level with augmented correlation-consistent basis sets, internally contacted multi-reference configuration interaction, and the newly developed CCSD(T)-F12 methods in connection with the explicitly correlated basis sets. Core-valence correction and scalar relativistic effects were examined. Our data consist of a set of spectroscopic parameters (equilibrium geometries, harmonic vibrational frequencies, rotational constants, spin-orbit, and spin-spin constants), adiabatic ionization energies, and electron affinities. For the low laying electronic states, our calculations are consistent with previous works whereas the high excited states present rather different shapes. Based on these new computations, the earlier ultraviolet bands of PS and PS(+) were reassigned. For PS(-) and in addition to the already known anionic three bound electronic states (i.e., X(3)?(-), (1)?, and 1(1)?(+)), our calculations show that the (1)?(-), (3)?(+), and the (3)? states are energetically below their quartet parent neutral state (a(4)?). The depletion of the J = 3 component of PS(-)((3)?) will mainly occur via weak interactions with the electron continuum wave. PMID:22755576

Ben Yaghlane, Saida; Francisco, Joseph S; Hochlaf, Majdi

2012-06-28

385

N-terminal domains of putative helicases of flavi- and pestiviruses may be serine proteases.  

PubMed Central

Recently we tentatively identified, by sequence comparison, central domains of the NS3 proteins of flaviviruses and the respective portion of the pestivirus polyprotein as RNA helicases (A.E.G. et al., submitted). Alignment of the N-proximal domains of the same proteins revealed conservation of short sequence stretches resembling those around the catalytic Ser, His and Asp residues of chymotrypsin-like proteases. A statistically significant similarity has been detected between the sequences of these domains and those of the C-terminal serine protease domains of alphavirus capsid proteins. It is suggested that flavivirus NS3 and the respective pestivirus protein contain at least two functional domains, the N-proximal protease and the C-proximal helicase one. The protease domain is probably involved in the processing of viral non-structural proteins. PMID:2543956

Gorbalenya, A E; Donchenko, A P; Koonin, E V; Blinov, V M

1989-01-01

386

Fray, a Drosophila serine/threonine kinase homologous to mammalian PASK, is required for axonal ensheathment  

NASA Technical Reports Server (NTRS)

Fray is a serine/threonine kinase expressed by the peripheral glia of Drosophila, whose function is required for normal axonal ensheathment. Null fray mutants die early in larval development and have nerves with severe swelling and axonal defasciculation. The phenotype is associated with a failure of the ensheathing glia to correctly wrap peripheral axons. When the fray cDNA is expressed in the ensheathing glia of fray mutants, normal nerve morphology is restored. Fray belongs to a novel family of Ser/Thr kinases, the PF kinases, whose closest relatives are the PAK kinases. Rescue of the Drosophila mutant phenotype with PASK, the rat homolog of Fray, demonstrates a functional homology among these proteins and suggests that the Fray signaling pathway is widely conserved.

Leiserson, W. M.; Harkins, E. W.; Keshishian, H.

2000-01-01

387

Selective inhibition of plant serine hydrolases by agrochemicals revealed by competitive ABPP.  

PubMed

Organophosphate and -phosphonates and their thio derivatives are often used in agroindustry as herbicides and insecticides, but their potential off-targets in the plant are poorly investigated. Here, we use competitive activity-based protein profiling (ABPP) of serine hydrolases (SHs) to detect targets of these agrochemicals and other compounds in Arabidopsis thaliana. Using broad-range and specific probes, and by overexpression of various SHs in planta, we are able to confirm eight SH-compound interactions, including selective inhibition of carboxylesterase CXE12, prolyloligopeptidase, methylesterase MES2 and tripeptidyl peptidase TPP2. These observations can be used for the design of novel probes and selective inhibitors and may help to assess physiological effects of agrochemicals on crop plants. PMID:21764588

Kaschani, Farnusch; Nickel, Sabrina; Pandey, Bikram; Cravatt, Benjamin F; Kaiser, Markus; van der Hoorn, Renier A L

2012-01-15

388

Selective Inhibition of Plant Serine Hydrolases by Agrochemicals Revealed by Competitive ABPP  

PubMed Central

Organophosphate and –phosphonates and their thiol derivatives are often used in agroindustry as herbicides and insecticides, but their potential off-targets in the plant and their consumers are poorly investigated. Here, we use competitive Activity-based Protein Profiling (ABPP) of serine hydrolases (SHs) to detect targets of these agrochemicals and other compounds in Arabidopsis thaliana. Using broad-range and specific probes, and by overexpression of various SHs in planta, we are able to confirm eight SH-compound interactions, including selective inhibition of carboxylesterase CXE12, prolyloligopeptidase, methylesterase MES2 and tripeptidyl peptidase TPP2. These observations can be used for the design of novel probes and selective inhibitors and may help to assess physiological effects of agrochemicals on crop plants. PMID:21764588

Kaschani, Farnusch; Nickel, Sabrina; Pandey, Bikram; Cravatt, Benjamin F.; Kaiser, Markus; van der Hoorn, Renier A. L.

2013-01-01

389

An unexpected tetragonal unit cell for N-(L-2-aminobutyryl)-L-serine.  

PubMed

The title dipeptide {systematic name: (S)-2-[(S)-2-azaniumylbutanamido]-3-hydroxypropanoate}, C?H??N?O?, was synthesized in the anticipation that it would form nanoporous crystals with hexagonal symmetry. Single-crystal X-ray diffraction analysis showed that it had instead adopted a unit cell in the space group I4, similar to L-alanyl-L-alanine [Fletterick, Tsai & Hughes (1970). J. Phys. Chem. 75, 918-922]. The resulting packing arrangement has a high density for a peptide (1.462 Mg m?³), which is rendered possible by extensive disorder over two positions for the ethyl side chain of the 2-aminobutyric acid fragment and over three positions for the serine side chain. PMID:23907883

Görbitz, Carl Henrik; Yadav, Vitthal N

2013-08-01

390

Bumblebee venom serine protease increases fungal insecticidal virulence by inducing insect melanization.  

PubMed

Insect-killing (entomopathogenic) fungi have high potential for controlling agriculturally harmful pests. However, their pathogenicity is slow, and this is one reason for their poor acceptance as a fungal insecticide. The expression of bumblebee, Bombus ignitus, venom serine protease (VSP) by Beauveria bassiana (ERL1170) induced melanization of yellow spotted longicorn beetles (Psacothea hilaris) as an over-reactive immune response, and caused substantially earlier mortality in beet armyworm (Spodopetra exigua) larvae when compared to the wild type. No fungal outgrowth or sporulation was observed on the melanized insects, thus suggesting a self-restriction of the dispersal of the genetically modified fungus in the environment. The research is the first use of a multi-functional bumblebee VSP to significantly increase the speed of fungal pathogenicity, while minimizing the dispersal of the fungal transformant in the environment. PMID:23626832

Kim, Jae Su; Choi, Jae Young; Lee, Joo Hyun; Park, Jong Bin; Fu, Zhenli; Liu, Qin; Tao, Xueying; Jin, Byung Rae; Skinner, Margaret; Parker, Bruce L; Je, Yeon Ho

2013-01-01

391

Expression and localization of Artemis serine 516 phosphorylation in human scalp skin.  

PubMed

Artemis phosphorylation at serine 516 (Ser516) has important regulatory functions in the repair of radiation-induced DNA damage, V(D)J recombination, p53-dependent apoptosis and cell cycle control. Accordingly, Artemis mutations can lead to Omenn syndrome, which is associated with human radiosensitive severe combined immunodeficiency syndrome and alopecia. In this study, we investigated the expression of Ser516 phosphorylation of Artemis in the epidermis and epidermal appendages in normal human scalp skin. Immunofluorescence analysis revealed Ser516 phosphorylation of Artemis in the upper and middle portion of anagen hair follicle [including outer root sheath (ORS), inner root sheath but not stratum basale], hair matrix, sebaceous glands (secretory and ductal portions), eccrine sweat glands (secretory and ductal portions) and epidermis (stratum basale and stratum granulosum), respectively. Artemis phosphorylation at Ser516 was most prominent in ORS keratinocytes. Therefore, we suggest that phosphorylation of Artemis at Ser516 could be involved in regulation of human epidermal appendages. PMID:23163657

Wu, Xian-Jie; Jing, Jing; Zhu, Jian-Wei; Xue, Dan; Liu, Hai; Böhm, Markus; Lu, Zhong-Fa; Zheng, Min

2012-11-01

392

The Rex proteins of human T-cell leukemia virus type II differ by serine phosphorylation.  

PubMed Central

The Rex proteins of human T-cell leukemia virus types I and II (HTLV-I and HTLV-II) induce cytoplasmic expression of unspliced gag-pol mRNA and singly spliced env mRNA and are critical for virus replication. Two rex gene products, p27rex and p21rex of HTLV-I and p26rex and p24rex of HTLV-II, have been detected in HTLV-infected cells; however, the structural and biological relationship of the proteins has not been clearly elucidated. Endoproteinase digestion and phosphoamino acid analysis of HTLV-II Rex indicated that p24rex has the same amino acid backbone as p26rex and that the larger apparent molecular size of p26rex is attributable to serine phosphorylation. Images PMID:1898667

Green, P L; Xie, Y M; Chen, I S

1991-01-01

393

Serine palmitoyltransferase, the first step enzyme in sphingolipid biosynthesis, is involved in nonhost resistance.  

PubMed

An overexpression screen of Nicotiana benthamiana cDNAs identified a gene for the LCB2 subunit of serine palmitoyltransferase (SPT) as a potent inducer of hypersensitive response-like cell death. The pyridoxal 5'-phosphate binding site of NbLCB2 is required for its function as a cell death inducer. NbLCB2 mRNA is accumulated after infection by nonhost pathogen Pseudomonas cichorii. Resistance of N. benthamiana against P. cichorii was compromised by treatment with an SPT inhibitor and in NbLCB2- and NbLCB1-silenced plants. These results suggest that biosynthesis of sphingolipids is necessary for the nonhost resistance of N. benthamiana against P. cichorii. PMID:19061400

Takahashi, Yoshihiro; Berberich, Thomas; Kanzaki, Hiroyuki; Matsumura, Hideo; Saitoh, Hiromasa; Kusano, Tomonobu; Terauchi, Ryohei

2009-01-01

394

Sulfated, Low Molecular Weight Lignins Inhibit a Select Group of Heparin-Binding Serine Proteases  

PubMed Central

Sulfated low molecular weight lignins (LMWLs), designed as oligomeric mimetics of low molecular weight heparins (LMWHs), have been found to bind in exosite II of thrombin (Abdel Aziz et al. Biochem. Biophys. Res. Commun. 413 (2011) 348–352). To assess whether sulfated LMWLs recognize other heparin-binding proteins, we studied their effect on serine proteases of the coagulation, inflammatory and digestive systems. Using chromogenic substrate hydrolysis assay, sulfated LMWLs were found to potently inhibit coagulation factor XIa and human leukocyte elastase, moderately inhibit cathepsin G and not inhibit coagulation factors VIIa, IXa, and XIIa, plasma kallikrein, activated protein C, trypsin, and chymotrypsin. Competition studies show that UFH competes with sulfated LMWLs for binding to factors Xa and XIa. These results further advance the heparin-mimicking property of sulfated LMWLs and will aid the design of anticoagulants based on their novel scaffold. PMID:22155248

Henry, Brian L.; Thakkar, Jay N.; Liang, Aiye; Desai, Umesh R.

2012-01-01

395

Structural basis for the catalytic activity of human serine/threonine protein phosphatase-5.  

PubMed

Serine/threonine protein phosphatase-5 (PP5) affects many signaling networks that regulate cell growth and cellular responses to stress. Here we report the crystal structure of the PP5 catalytic domain (PP5c) at a resolution of 1.6 A. From this structure we propose a mechanism for PP5-mediated hydrolysis of phosphoprotein substrates, which requires the precise positioning of two metal ions within a conserved Asp271-M1:M2-W1-His427-His304-Asp274 catalytic motif (where M1 and M2 are metals and W1 is a water molecule). The structure of PP5c provides a structural basis for explaining the exceptional catalytic proficiency of protein phosphatases, which are among the most powerful known catalysts. Resolution of the entire C terminus revealed a novel subdomain, and the structure of the PP5c should also aid development of type-specific inhibitors. PMID:15155720

Swingle, Mark R; Honkanen, Richard E; Ciszak, Ewa M

2004-08-01

396

Hydroxyapatite crystallization in the presence of serine, tyrosine and hydroxyproline amino acids with polar side groups  

NASA Astrophysics Data System (ADS)

Addition of the amino acids serine, tyrosine and 4-hydroxyproline with polar uncharged side groups at physiological pH levels to a supersaturated calcium phosphate solution reduced the crystal growth rate of hydroxyapatite (HAP) at 37°C. Depending on the side group of the amino acid different inhibiting activities were observed. The reduction was also found to be related to the additive concentration following an expression suggested by the kinetic Langmuir-type adsorption model. This relationship implies that HAP crystallization kinetics was affected through blockage of the active growth sites on the crystal surface. In all cases the apparent order of the crystal growth reaction was found to be n=2, suggesting a surface-diffusion-controlled spiral growth mechanism.

Koutsopoulos, S.; Dalas, E.

2000-06-01

397

Tissue-specific distribution of serine/threonine protein phosphatase 1 of Toxocara canis.  

PubMed

Serine/threonine protein phosphatase 1 (PP1) is expressed in developing and reproductively active male Toxocara canis. To investigate the tissue-specific expression of PP1 in T. canis, the PP1 protein was expressed in Escherichia coli, and the recombinant protein was used to generate a rabbit polyclonal antiserum. Indirect fluorescence immunohistochemical analysis of adult male T. canis showed that PP1 was expressed in the germ line tissues, primarily in the testis, seminal vesicle, vas deferens, and sperm cells, indicating the potential roles of PP1 in spermatogenesis. What's more, structural predictions of PP1 in T. canis were performed. The predictions of the structure indicated that PP1 may be a potential target for antihelmintic drugs. This is the first report of the tissue distributions and structural prediction of PP1 in T. canis, which might lead to the development of novel, innovative strategies for controlling T. canis infestations. PMID:25282049

Ma, Guang Xu; Zhou, Rong Qiong; Huang, Han Cheng; Hu, Shi Jun; Lin, Jie

2014-10-15

398

Inactivation of the serine proteinase operon (proMCD) of Staphylococcus warneri M: serine proteinase and cysteine proteases are involved in the autolysis.  

PubMed

Unlike other members of coagulase negative staphylococci (CNS), strain warneri has proMCD operon, a homologue of sspABC proteinase operon of S. aureus. The proM and proC encode serine glutamyl endopeptidase and cysteine protease respectively, whereas proD directs homologue of SspC, putative cytoplasmic inhibitor which protects the host bacterium from premature activation of SspB. We determined whole nucleotide sequence of proMCD operon of S. warneri M, succeeded in expression of these genes, and investigated their functions by gene inactivation and complementation experiments. In gelatin zymography of the culture supernatant, a 20-kDa band corresponding to PROC cysteine protease was detected. By Western blotting, PROD was also confirmed in the cytoplasmic protein fraction. PROC and PROD showed significant similarity to SspB and SspC of S. aureus (73% and 58%, respectively). Inactivation mutants of proMCD, proCD and proD genes were established, separately. In the proMCD mutant, degradation/processing of extracellular proteins was drastically reduced, suggesting that PROM was responsible for the cleavage of extracellular proteins. By the proD mutation, the growth profile was not affected, and secretion of PROC was retained. Extracellular protein profiles of the proCD and proD mutants were not so different each other, but autolysin profiles were slightly dissimilar, around 39-48 kDa and 20kDa bands in zymogram. Experiments in buffer systems showed that autolysis was significantly diminished in proMCD mutant, and was promoted by addition of purified PROM. The proC gene was cloned into a multicopy plasmid, and introduced into the proMCD mutant. Compared with the wild type, autolysis of the proC-complemented strain was definitely enhanced by addition of purified PROM. These results suggested that PROM and PROC affected the coccal autolysis, through processing of the autolysin. PMID:23107764

Yokoi, Ken-Ji; Kuzuwa, Shinya; Kondo, Mitsuru; Yamakawa, Ayanori; Taketo, Akira; Kodaira, Ken-Ichi

2013-01-10

399

H-bond network in amino acid cocrystals with H2O or H2O2. The DFT study of serine-H2O and serine-H2O2.  

PubMed

The structure, IR spectrum, and H-bond network in the serine-H(2)O and serine-H(2)O(2) crystals were studied using DFT computations with periodic boundary conditions. Two different basis sets were used: the all-electron Gaussian-type orbital basis set and the plane wave basis set. Computed frequencies of the IR-active vibrations of the titled crystals are quite different in the range of 10-100 cm(-1). Harmonic approximation fails to reproduce IR active bands in the 2500-2800 frequency region of serine-H(2)O and serine-H(2)O(2). The bands around 2500 and 2700 cm(-1) do exist in the anharmonic IR spectra and are caused by the first overtone of the OH bending vibrations of H(2)O and a combination vibration of the symmetric and asymmetric bendings of H(2)O(2). The quantum-topological analysis of the crystalline electron density enables us to describe quantitatively the H-bond network. It is much more complex in the title crystals than in a serine crystal. Appearance of water leads to an increase of the energy of the amino acid-amino acid interactions, up to ~50 kJ/mol. The energy of the amino acid-water H-bonds is ~30 kJ/mol. The H(2)O/H(2)O(2) substitution does not change the H-bond network; however, the energy of the amino acid-H(2)O(2) contacts increases up to 60 kJ/mol. This is caused by the fact that H(2)O(2) is a much better proton donor than H(2)O in the title crystals. PMID:22004006

Vener, Mikhail V; Medvedev, Alexander G; Churakov, Andrei V; Prikhodchenko, Petr V; Tripol'skaya, Tatiana A; Lev, Ovadia

2011-11-24

400

TMEM43 Mutation p.S358L Alters Intercalated Disc Protein Expression and Reduces Conduction Velocity in  

E-print Network

showed that the stable expression of p.S358L mutation in the HL-1 cardiac cell line resulted in decreasedTMEM43 Mutation p.S358L Alters Intercalated Disc Protein Expression and Reduces Conduction Velocity death. A heterozygous missense mutation in the transmembrane protein 43 (TMEM43) gene, p.S358L, has been

Sun, Yu

401

Preparation of fatty acid methyl esters and dimethylacetals from lipids with boron fluoride-methanol  

Microsoft Academic Search

SUMMARY Fatty acid methyl esters and dimethylacetals suitable for gas chromatographic analysis were prepared by treatment of lipids with boron fluoride-methanol (140 g BFI per liter of methanol). This reagent is stable and easy to handle. Reaction conditions were investigated for triglycerides, di- glycerides, monoglycerides, free fatty acids, sterol esters, phos- phatidyl ethanolamines, phosphatidyl serines, phosphatidyl 'cholines, monophosphoinositides, monogalactosyl glycerides,

WILLIAM R. MORRISON; LLOYD M. SMITH

402

IrSPI, a Tick Serine Protease Inhibitor Involved in Tick Feeding and Bartonella henselae Infection  

PubMed Central

Ixodes ricinus is the most widespread and abundant tick in Europe, frequently bites humans, and is the vector of several pathogens including those responsible for Lyme disease, Tick-Borne Encephalitis, anaplasmosis, babesiosis and bartonellosis. These tick-borne pathogens are transmitted to vertebrate hosts via tick saliva during blood feeding, and tick salivary gland (SG) factors are likely implicated in transmission. In order to identify such tick factors, we characterized the transcriptome of female I. ricinus SGs using next generation sequencing techniques, and compared transcriptomes between Bartonella henselae-infected and non-infected ticks. High-throughput sequencing of I. ricinus SG transcriptomes led to the generation of 24,539 isotigs. Among them, 829 and 517 transcripts were either significantly up- or down-regulated respectively, in response to bacterial infection. Searches based on sequence identity showed that among the differentially expressed transcripts, 161 transcripts corresponded to nine groups of previously annotated tick SG gene families, while the others corresponded to genes of unknown function. Expression patterns of five selected genes belonging to the BPTI/Kunitz family of serine protease inhibitors, the tick salivary peptide group 1 protein, the salp15 super-family, and the arthropod defensin family, were validated by qRT-PCR. IrSPI, a member of the BPTI/Kunitz family of serine protease inhibitors, showed the highest up-regulation in SGs in response to Bartonella infection. IrSPI silencing impaired tick feeding, as well as resulted in reduced bacterial load in tick SGs. This study provides a comprehensive analysis of I. ricinus SG transcriptome and contributes significant genomic information about this important disease vector. This in-depth knowledge will enable a better understanding of the molecular interactions between ticks and tick-borne pathogens, and identifies IrSPI, a candidate to study now in detail to estimate its potentialities as vaccine against the ticks and the pathogens they transmit. PMID:25057911

Liu, Xiang Ye; de la Fuente, Jose; Cote, Martine; Galindo, Ruth C.; Moutailler, Sara; Vayssier-Taussat, Muriel; Bonnet, Sarah I.

2014-01-01

403

The Serine Protease Domain of MASP-3: Enzymatic Properties and Crystal Structure in Complex with Ecotin  

PubMed Central

Mannan-binding lectin (MBL), ficolins and collectin-11 are known to associate with three homologous modular proteases, the MBL-Associated Serine Proteases (MASPs). The crystal structures of the catalytic domains of MASP-1 and MASP-2 have been solved, but the structure of the corresponding domain of MASP-3 remains unknown. A link between mutations in the MASP1/3 gene and the rare autosomal recessive 3MC (Mingarelli, Malpuech, Michels and Carnevale,) syndrome, characterized by various developmental disorders, was discovered recently, revealing an unexpected important role of MASP-3 in early developmental processes. To gain a first insight into the enzymatic and structural properties of MASP-3, a recombinant form of its serine protease (SP) domain was produced and characterized. The amidolytic activity of this domain on fluorescent peptidyl-aminomethylcoumarin substrates was shown to be considerably lower than that of other members of the C1r/C1s/MASP family. The E. coli protease inhibitor ecotin bound to the SP domains of MASP-3 and MASP-2, whereas no significant interaction was detected with MASP-1, C1r and C1s. A tetrameric complex comprising an ecotin dimer and two MASP-3 SP domains was isolated and its crystal structure was solved and refined to 3.2 Å. Analysis of the ecotin/MASP-3 interfaces allows a better understanding of the differential reactivity of the C1r/C1s/MASP protease family members towards ecotin, and comparison of the MASP-3 SP domain structure with those of other trypsin-like proteases yields novel hypotheses accounting for its zymogen-like properties in vitro. PMID:23861840

Gaboriaud, Christine; Gupta, Rajesh Kumar; Martin, Lydie; Lacroix, Monique; Serre, Laurence; Teillet, Florence; Arlaud, Gérard J.; Rossi, Véronique; Thielens, Nicole M.

2013-01-01

404

Characterization of a Serine Hydrolase Targeted by Acyl-protein Thioesterase Inhibitors in Toxoplasma gondii  

PubMed Central

In eukaryotic organisms, cysteine palmitoylation is an important reversible modification that impacts protein targeting, folding, stability, and interactions with partners. Evidence suggests that protein palmitoylation contributes to key biological processes in Apicomplexa with the recent palmitome of the malaria parasite Plasmodium falciparum reporting over 400 substrates that are modified with palmitate by a broad range of protein S-acyl transferases. Dynamic palmitoylation cycles require the action of an acyl-protein thioesterase (APT) that cleaves palmitate from substrates and conveys reversibility to this posttranslational modification. In this work, we identified candidates for APT activity in Toxoplasma gondii. Treatment of parasites with low micromolar concentrations of ?-lactone- or triazole urea-based inhibitors that target human APT1 showed varied detrimental effects at multiple steps of the parasite lytic cycle. The use of an activity-based probe in combination with these inhibitors revealed the existence of several serine hydrolases that are targeted by APT1 inhibitors. The active serine hydrolase, TgASH1, identified as the homologue closest to human APT1 and APT2, was characterized further. Biochemical analysis of TgASH1 indicated that this enzyme cleaves substrates with a specificity similar to APTs, and homology modeling points toward an APT-like enzyme. TgASH1 is dispensable for parasite survival, which indicates that the severe effects observed with the ?-lactone inhibitors are caused by the inhibition of non-TgASH1 targets. Other ASH candidates for APT activity were functionally characterized, and one of them was found to be resistant to gene disruption due to the potential essential nature of the protein. PMID:23913689

Kemp, Louise E.; Rusch, Marion; Adibekian, Alexander; Bullen, Hayley E.; Graindorge, Arnault; Freymond, Céline; Rottmann, Matthias; Braun-Breton, Catherine; Baumeister, Stefan; Porfetye, Arthur T.; Vetter, Ingrid R.; Hedberg, Christian; Soldati-Favre, Dominique

2013-01-01

405

Comparative Mitogenomics of Plant Bugs (Hemiptera: Miridae): Identifying the AGG Codon Reassignments between Serine and Lysine  

PubMed Central

Insect mitochondrial genomes are very important to understand the molecular evolution as well as for phylogenetic and phylogeographic studies of the insects. The Miridae are the largest family of Heteroptera encompassing more than 11,000 described species and of great economic importance. For better understanding the diversity and the evolution of plant bugs, we sequence five new mitochondrial genomes and present the first comparative analysis of nine mitochondrial genomes of mirids available to date. Our result showed that gene content, gene arrangement, base composition and sequences of mitochondrial transcription termination factor were conserved in plant bugs. Intra-genus species shared more conserved genomic characteristics, such as nucleotide and amino acid composition of protein-coding genes, secondary structure and anticodon mutations of tRNAs, and non-coding sequences. Control region possessed several distinct characteristics, including: variable size, abundant tandem repetitions, and intra-genus conservation; and was useful in evolutionary and population genetic studies. The AGG codon reassignments were investigated between serine and lysine in the genera Adelphocoris and other cimicomorphans. Our analysis revealed correlated evolution between reassignments of the AGG codon and specific point mutations at the antidocons of tRNALys and tRNASer(AGN). Phylogenetic analysis indicated that mitochondrial genome sequences were useful in resolving family level relationship of Cimicomorpha. Comparative evolutionary analysis of plant bug mitochondrial genomes allowed the identification of previously neglected coding genes or non-coding regions as potential molecular markers. The finding of the AGG codon reassignments between serine and lysine indicated the parallel evolution of the genetic code in Hemiptera mitochondrial genomes. PMID:24988409

Wang, Pei; Song, Fan; Cai, Wanzhi

2014-01-01

406

Regulation of the epithelial Na+ channel and airway surface liquid volume by serine proteases  

PubMed Central

Mammalian airways are protected from infection by a thin film of airway surface liquid (ASL) which covers airway epithelial surfaces and acts as a lubricant to keep mucus from adhering to the epithelial surface. Precise regulation of ASL volume is essential for efficient mucus clearance and too great a reduction in ASL volume causes mucus dehydration and mucus stasis which contributes to chronic airway infection. The epithelial Na+ channel (ENaC) is the rate-limiting step that governs Na+ absorption in the airways. Recent in vitro and in vivo data have demonstrated that ENaC is a critical determinant of ASL volume and hence mucus clearance. ENaC must be cleaved by either intracellular furin-type proteases or extracellular serine proteases to be active and conduct Na+, and this process can be inhibited by protease inhibitors. ENaC can be regulated by multiple pathways, and once proteolytically cleaved ENaC may then be inhibited by intracellular second messengers such as cAMP and PIP2. In the airways, however, regulation of ENaC by proteases seems to be the predominant mode of regulation since knockdown of either endogenous serine proteases such as prostasin, or inhibitors of ENaC proteolysis such as SPLUNC1, has large effects on ENaC activity in airway epithelia. In this review, we shall discuss how ENaC is proteolytically cleaved, how this process can regulate ASL volume, and how its failure to operate correctly may contribute to chronic airway disease. PMID:20401730

Gaillard, Erol A.; Kota, Pradeep; Gentzsch, Martina; Dokholyan, Nikolay V.; Stutts, M. Jackson

2010-01-01

407

27?Serine Protease Inhibitor Attenuates Ova Induced Inflammation in Mouse Model of Allergic Airway Disease  

PubMed Central

Background Serine proteases promote inflammation and tissue remodeling by activating proteinase-activated receptors, urokinase, metalloproteinases and angiotensin. In the present study, AEBSF (4-(2-Aminoethyl) benzenesulfonyl fluoride) a serine protease inhibitor, was evaluated for prophylactic and therapeutic treatment in mouse model of airway allergy. Methods BALB/c mice were sensitized by i.p route on 0 and 14 day and challenged with OVA (25, 26 and 27 day) by i.n. route. Mice were treated i.n. with AEBSF, 1 hour before/after challenge and sacrificed on day 29 to collect BALF, blood and lungs. OVA specific immunoglobulins were measured in serum. Proteolytic activity, total cell/eosinophil count, eosinophil peroxidase activity (EPO), IL-4, IL-5, IL-10, cysteinyl leukotrienes and 8-isoprostane (oxidative stress marker) were determined in BALF. Haematoxylin and eosin stained lung sections were examined for cellular infiltration and airway inflammation. Results Mice exposed to OVA and treated with PBS showed significantly high levels of IgE, IgG1 and IgG2a as compared to sham mice. Both prophylactic and symptomatic AEBSF treatment reduced serum IgE and IgG1 significantly (P ? 0.05) than control, however there was little increment in IgG2a level. AEBSF could effectively reduce the proteolytic activity in BALF. IL-4 and IL-5 decreased significantly (P ? 0.05) after AEBSF treatment while a significant (P ? 0.05) increase was observed in IL-10 in BALF. Airway inflammation reduced significantly as revealed by lung histopathology, EPO activity and cysteinyl leukotrienes in BALF after treatment. AEBSF also suppressed oxidative stress in terms of 8-isoprostane in BALF. Among the treatment doses, 10 and 50 ?g of AEBSF were most effective in reducing majority of the inflammatory parameters. Conclusions Prophylactic and therapeutic treatment of AEBSF attenuates the airway inflammation in mouse model of airway allergy and have potential for the treatment of inflammatory allergic diseases.

Sawc, Sanjay; Kalec, Sagar; Singh, Bhanu Pratap; Arora, Naveen

2012-01-01

408

The presequence of Arabidopsis serine hydroxymethyltransferase SHM2 selectively prevents import into mesophyll mitochondria.  

PubMed

Serine hydroxymethyltransferases (SHMs) are important enzymes of cellular one-carbon metabolism and are essential for the photorespiratory glycine-into-serine conversion in leaf mesophyll mitochondria. In Arabidopsis (Arabidopsis thaliana), SHM1 has been identified as the photorespiratory isozyme, but little is known about the very similar SHM2. Although the mitochondrial location of SHM2 can be predicted, some data suggest that this particular isozyme could be inactive or not targeted into mitochondria. We report that SHM2 is a functional mitochondrial SHM. In leaves, the presequence of SHM2 selectively hinders targeting of the enzyme into mesophyll mitochondria. For this reason, the enzyme is confined to the vascular tissue of wild-type Arabidopsis, likely the protoxylem and/or adjacent cells, where it occurs together with SHM1. The resulting exclusion of SHM2 from the photorespiratory environment of mesophyll mitochondria explains why this enzyme cannot substitute for SHM1 in photorespiratory metabolism. Unlike the individual shm1 and shm2 null mutants, which require CO(2)-enriched air to inhibit photorespiration (shm1) or do not show any visible impairment (shm2), double-null mutants cannot survive in CO(2)-enriched air. It seems that SHM1 and SHM2 operate in a redundant manner in one-carbon metabolism of nonphotorespiring cells with a high demand of one-carbon units; for example, during lignification of vascular cells. We hypothesize that yet unknown kinetic properties of SHM2 might render this enzyme unsuitable for the high-folate conditions of photorespiring mesophyll mitochondria. PMID:21976482

Engel, Nadja; Ewald, Ralph; Gupta, Kapuganti J; Zrenner, Rita; Hagemann, Martin; Bauwe, Hermann

2011-12-01

409

Pest Protection Conferred by a Beta vulgaris Serine Proteinase Inhibitor Gene  

PubMed Central

Proteinase inhibitors provide a means of engineering plant resistance to insect pests. A Beta vulgaris serine proteinase inhibitor gene (BvSTI) was fused to the constitutive CaMV35S promoter for over-expression in Nicotiana benthamiana plants to study its effect on lepidopteran insect pests. Independently derived BvSTI transgenic tobacco T2 homozygous progeny were shown to have relatively high BvSTI gene transcript levels. BvSTI-specific polyclonal antibodies cross-reacted with the expected 30 kDA recombinant BvSTI protein on Western blots. In gel trypsin inhibitor activity assays revealed a major clear zone that corresponded to the BvSTI proteinase inhibitor that was not detected in the untransformed control plants. BvSTI-transgenic plants were bioassayed for resistance to five lepidopteran insect pests. Spodoptera frugiperda, S. exigua and Manduca sexta larvae fed BvSTI leaves had significant reductions in larval weights as compared to larvae fed on untransformed leaves. In contrast, larval weights increased relative to the controls when Heliothis virescens and Agrotis ipsilon larvae were fed on BvSTI leaves. As the larvae entered the pupal stage, pupal sizes reflected the overall larval weights. Some developmental abnormalities of the pupae and emerging moths were noted. These findings suggest that the sugar beet BvSTI gene may prove useful for effective control of several different lepidopteran insect pests in genetically modified tobacco and other plants. The sugar beet serine proteinase inhibitor may be more effective for insect control because sugar beet is cropped in restricted geographical areas thus limiting the exposure of the insects to sugar beet proteinase inhibitors and build up of non-sensitive midgut proteases. PMID:23468963

Smigocki, Ann C.; Ivic-Haymes, Snezana; Li, Haiyan; Savi?, Jelena

2013-01-01

410

Mutations in a novel serine protease PRSS56 in families with nanophthalmos  

PubMed Central

Purpose Nanophthalmos is a rare genetic ocular disorder in which the eyes of affected individuals are abnormally small. Patients suffer from severe hyperopia as a result of their markedly reduced axial lengths, but otherwise are capable of seeing well unlike other more general forms of microphthalmia. To date one gene for nanophthalmos has been identified, encoding the membrane-type frizzled related protein MFRP. Identification of additional genes for nanophthalmos will improve our understanding of normal developmental regulation of eye growth. Methods We ascertained a cohort of families from eastern Canada and Mexico with familial nanophthalmos. We performed high density microsatellite and high density single nucleotide polymorphism (SNP) genotyping to identify potential chromosomal regions of linkage. We sequenced coding regions of genes in the linked interval by traditional PCR-based Sanger capillary electrophoresis methods. We cloned and sequenced a novel cDNA from a putative causal gene to verify gene structure. Results We identified a linked locus on chromosome 2q37 with a peak logarithm (base 10) of odds (LOD) score of 4.7. Sequencing of coding exons of all genes in the region identified multiple segregating variants in one gene, recently annotated as serine protease gene (PRSS56), coding for a predicted trypsin serine protease-like protein. One of our families was homozygous for a predicted pathogenic missense mutation, one family was compound heterozygous for two predicted pathogenic missense mutations, and one family was compound heterozygous for a predicted pathogenic missense mutation plus a frameshift leading to obligatory truncation of the predicted protein. The PRSS56 gene structure in public databases is based on a virtual transcript assembled from overlapping incomplete cDNA clones; we have now validated the structure of a full-length transcript from embryonic mouse brain RNA. Conclusions PRSS56 is a good candidate for the causal gene for nanophthalmos in our families. PMID:21850159

Dubé, Marie-Pierre; Zenteno, Juan C.; Jiang, Haiyan; Asselin, Geraldine; Evans, Susan C.; Caqueret, Aurore; Lakosha, Hesham; Letourneau, Louis; Marcadier, Julien; Matsuoka, Makoto; Macgillivray, Christine; Nightingale, Mathew; Papillon-Cavanagh, Simon; Perry, Scott; Provost, Sylvie; Ludman, Mark; Guernsey, Duane L.; Samuels, Mark E.

2011-01-01

411

Conformational transitions driven by pyridoxal-5'-phosphate uptake in the psychrophilic serine hydroxymethyltransferase from Psychromonas ingrahamii.  

PubMed

Serine hydroxymethyltransferase (SHMT) is a pyridoxal-5'-phosphate (PLP)-dependent enzyme belonging to the fold type I superfamily, which catalyzes in vivo the reversible conversion of l-serine and tetrahydropteroylglutamate (H4 PteGlu) to glycine and 5,10-methylenetetrahydropteroylglutamate (5,10-CH(2) -H(4) PteGlu). The SHMT from the psychrophilic bacterium Psychromonas ingrahamii (piSHMT) had been recently purified and characterized. This enzyme was shown to display catalytic and stability properties typical of psychrophilic enzymes, namely high catalytic activity at low temperature and thermolability. To gain deeper insights into the structure-function relationship of piSHMT, the three-dimensional structure of its apo form was determined by X-ray crystallography. Homology modeling techniques were applied to build a model of the piSHMT holo form. Comparison of the two forms unraveled the conformation modifications that take place when the apo enzyme binds its cofactor. Our results show that the apo form is in an "open" conformation and possesses four (or five, in chain A) disordered loops whose electron density is not visible by X-ray crystallography. These loops contain residues that interact with the PLP cofactor and three of them are localized in the major domain that, along with the small domain, constitutes the single subunit of the SHMT homodimer. Cofactor binding triggers a rearrangement of the small domain that moves toward the large domain and screens the PLP binding site at the solvent side. Comparison to the mesophilic apo SHMT from Salmonella typhimurium suggests that the backbone conformational changes are wider in psychrophilic SHMT. PMID:25044250

Angelaccio, Sebastiana; Dworkowski, Florian; Di Bello, Angela; Milano, Teresa; Capitani, Guido; Pascarella, Stefano

2014-10-01

412

Effect of a serine protease inhibitor on the progression of chronic renal failure.  

PubMed

The number of the chronic renal failure (CRF) patients is increasing explosively. Hypertension, proteinuria, inflammation, fibrosis, and oxidative stress are intertwined in a complicated manner that leads to the progression of CRF. However, the therapeutic strategies to delay its progression are limited. Since serine proteases are involved in many processes that contribute to these risk factors, we investigated the effects of a synthetic serine protease inhibitor, camostat mesilate (CM), on the progression of CRF in 5/6 nephrectomized (Nx) rats. Eighteen male Sprague-Dawley rats were divided into three groups: a sham-operated group (n = 6), a vehicle-treated Nx group (n = 6), and a CM-treated Nx group (n = 6). Following the 9-wk study period, both proteinuria and serum creatinine levels were substantially increased in the vehicle-treated Nx group, and treatment with CM significantly reduced proteinuria and serum creatinine levels. The levels of podocyte-associated proteins in glomeruli, such as nephrin and synaptopodin, were markedly decreased by 5/6 nephrectomy, and this was significantly ameliorated by CM. CM also suppressed the levels of inflammatory and fibrotic marker mRNAs including transforming growth factor-?1, TNF-?, collagen types I, III, and IV, and reduced glomerulosclerosis, glomerular hypertrophy, and interstitial fibrosis in histological studies. Furthermore, CM decreased the expression of NADPH oxidase component mRNAs, as well as reactive oxygen species generation and advanced oxidative protein product levels. Our present results strongly suggest the possibility that CM could be a useful therapeutic agent against the progression of CRF. PMID:22832926

Hayata, Manabu; Kakizoe, Yutaka; Uchimura, Kohei; Morinaga, Jun; Yamazoe, Rika; Mizumoto, Teruhiko; Onoue, Tomoaki; Ueda, Miki; Shiraishi, Naoki; Adachi, Masataka; Miyoshi, Taku; Sakai, Yoshiki; Tomita, Kimio; Kitamura, Kenichiro

2012-10-15

413

The antifibrotic effect of a serine protease inhibitor in the kidney.  

PubMed

Interstitial fibrosis is a final common pathway for the progression of chronic kidney diseases. Activated fibroblasts have an extremely important role in the progression of renal fibrosis, and transforming growth factor (TGF)-?? is a major activator of fibroblasts. Since previous reports have indicated that serine protease inhibitors have a potential to inhibit TGF-?? signaling in vitro, we hypothesized that a synthetic serine protease inhibitor, camostat mesilate (CM), could slow the progression of renal fibrosis. TGF-?? markedly increased the phosphorylation of TGF-? type I receptor, ERK 1/2, and Smad2/3 and the levels of profibrotic markers, such as ?-smooth muscle actin (?-SMA), connective tissue growth factor (CTGF), and plasminogen activator inhibitor-1, in renal fibroblasts (NRK-49F cells), and they were all significantly reduced by CM. In protocol 1, 8-wk-old male Sprague-Dawley rats were subjected to unilateral ureteral obstruction (UUO) and were concurrently treated with a slow-release pellet of CM or vehicle for 14 days. Protocol 2 was similar to protocol 1 except that CM was administered 7 days after UUO. CM substantially improved renal fibrosis as determined by sirius red staining, collagen expression, and hydroxyproline levels. The phosphorylation of ERK1/2 and Smad2/3 and the levels of ?-SMA, CTGF, promatrix metalloproteinase-2, and matrix metalloproteinase-2 were substantially increased by UUO, and they were all significantly attenuated by CM. These antifibrotic effects of CM were also observed in protocol 2. Our present results suggest the possibility that CM might represent a new class of therapeutic drugs for the treatment of renal fibrosis through the suppression of TGF-?? signaling. PMID:23698112

Morinaga, Jun; Kakizoe, Yutaka; Miyoshi, Taku; Onoue, Tomoaki; Ueda, Miki; Mizumoto, Teruhiko; Yamazoe, Rika; Uchimura, Kohei; Hayata, Manabu; Shiraishi, Naoki; Adachi, Masataka; Sakai, Yoshiki; Tomita, Kimio; Kitamura, Kenichiro

2013-07-15

414

Functional analysis of a subtilisin-like serine protease gene from biocontrol fungus Trichoderma harzianum.  

PubMed

The subtilisin-like serine protease gene ThSS45 has been cloned from Trichoderma harzianum ACCC30371. Its coding region is 1302 bp in length, encoding 433 amino acids, with a predicted protein molecular weight of 44.9 kDa and pI of 5.91. ThSS45 was shown by RT-qPCR analysis to be differentially transcribed in response to eight different treatments. The transcription of ThSS45 was up-regulated when grown in mineral medium, under carbon starvation, and nitrogen starvation, and in the presence of 1% root powder, 1% stem powder, and 1% leaf powder derived from Populus davidiana × P. bolleana (Shanxin poplar) aseptic seedlings. The highest increase in transcription approached 3.5-fold that of the control at 6 h under induction with 1% poplar root powder. The transcription of ThSS45 was also slightly up-regulated by 1% Alternaria alternata cell wall and 5% A. alternata fermentation liquid. Moreover, the analyses of coding and promoter regions of ThSS45 homologs indicated that serine protease may be involved in both mycoparasitism and antibiotic secretion. ThSS45 was cloned into the pGEX-4T-2 vector and then expressed in Escherichia coli BL21. The recombinant protein, with an expected molecular weight of approximately 69 kDa, was then purified. When transformant BL21-ss was induced with 1 mM IPTG for 6 h, the purified protease activity reached a peak of 18.25 U/ml at pH 7.0 and 40°C. In antifungal assays the purified protease obviously inhibited the growth of A. alternata mycelia. PMID:24500477

Fan, Haijuan; Liu, Zhihua; Zhang, Rongshu; Wang, Na; Dou, Kai; Mijiti, Gulijimila; Diao, Guiping; Wang, Zhiying

2014-02-01

415

Kinetic mechanism of the interaction of D-cycloserine with serine hydroxymethyltransferase.  

PubMed

The kinetic mechanism for the interaction of D-cycloserine with serine hydroxymethyltransferase (EC 2.1.2.1) from sheep liver was established by measuring changes in the activity, absorbance, and circular dichoism (CD) of the enzyme. The irreversible inhibition of the enzyme was characterized by three detectable steps: an initial rapid step followed by two successive steps with rate constants of 5.4 X 10(-3) s-1 and 1.4 X 10(-4) s-1. The first step was distinguished by a rapid disappearance of the enzyme absorbance peak at 425 nm, a decrease in the enzyme activity to 25% of the uninhibited velocity, and a lowering of the CD intensity at 432 nm to about 65% of the original value. The second step of the interaction was accompanied by a complete loss of enzyme activity and a marginal increase in the CD intensity at 432 nm. The final step resulted in the complete loss of the enzyme absorbance at 425 nm and of the CD band at 432 nm. The products of the reaction were identified as (a) apoenzyme by absorbance measurements, CD spectra, and reconstitution with pyridoxal 5'-phosphate and (b) a pyridoxal 5'-phosphate-D-cycloserine Schiff's base complex identified by its fluorescence and absorbance spectra. The Schiff base complex was expelled from the enzyme active site in the final step of the reaction. The proposed mechanism, which is different from those operative in other pyridoxal phosphate dependent enzymes, probably accounts for the selective inhibition of serine hydroxymethyltransferase by the drug in vivo. PMID:6487593

Manohar, R; Rao, A G; Rao, N A

1984-08-28

416

L-serine analogues form Schiff base and quinonoidal intermediates with Escherichia coli tryptophan synthase.  

PubMed

Substrate analogues of L-serine have been found that react with the alpha 2 beta 2 complex of Escherichia coli tryptophan synthase. Upon reaction with alpha 2 beta 2, the analogues glycine, L-histidine, L-alanine, and D-histidine form chemical intermediates derived from reaction with enzyme-bound pyridoxal 5'-phosphate with characteristic UV-visible spectral bands. The spectra of the products of the glycine, L-histidine, and L-alanine reactions with alpha 2 beta 2 contain contributions from the external aldimine, the quinonoid species, and other intermediates along the catalytic pathway. Just as previously reported for the reaction of L-serine with beta 2 [Goldberg, M. E., York, S., & Stryer, L. (1968) Biochemistry 7, 3662-3667], the reactions of glycine, L-histidine, and L-alanine with the beta 2 form of tryptophan synthase yield spectra with no contributions from catalytic intermediates beyond the external aldimine. The kinetics of intermediate formation and comparisons of the time courses for the exchange of alpha-1H for solvent 2H catalyzed by alpha 2 beta 2 or beta 2 were found to be consistent with these assignments. Intermediates further along the tryptophan synthase catalytic pathway are stabilized to a greater degree in the alpha 2 beta 2 complex than in the beta 2 species alone. This observation strongly suggests that the association of alpha and beta subunits to form the native alpha 2 beta 2 species lowers the activation energies for the interconversion of the external aldimine with chemical species further along the catalytic path.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2504276

Houben, K F; Kadima, W; Roy, M; Dunn, M F

1989-05-16

417

The serine protease domain of MASP-3: enzymatic properties and crystal structure in complex with ecotin.  

PubMed

Mannan-binding lectin (MBL), ficolins and collectin-11 are known to associate with three homologous modular proteases, the MBL-Associated Serine Proteases (MASPs). The crystal structures of the catalytic domains of MASP-1 and MASP-2 have been solved, but the structure of the corresponding domain of MASP-3 remains unknown. A link between mutations in the MASP1/3 gene and the rare autosomal recessive 3MC (Mingarelli, Malpuech, Michels and Carnevale,) syndrome, characterized by various developmental disorders, was discovered recently, revealing an unexpected important role of MASP-3 in early developmental processes. To gain a first insight into the enzymatic and structural properties of MASP-3, a recombinant form of its serine protease (SP) domain was produced and characterized. The amidolytic activity of this domain on fluorescent peptidyl-aminomethylcoumarin substrates was shown to be considerably lower than that of other members of the C1r/C1s/MASP family. The E. coli protease inhibitor ecotin bound to the SP domains of MASP-3 and MASP-2, whereas no significant interaction was detected with MASP-1, C1r and C1s. A tetrameric complex comprising an ecotin dimer and two MASP-3 SP domains was isolated and its crystal structure was solved and refined to 3.2 Å. Analysis of the ecotin/MASP-3 interfaces allows a better understanding of the differential reactivity of the C1r/C1s/MASP protease family members towards ecotin, and comparison of the MASP-3 SP domain structure with those of other trypsin-like proteases yields novel hypotheses accounting for its zymogen-like properties in vitro. PMID:23861840

Gaboriaud, Christine; Gupta, Rajesh Kumar; Martin, Lydie; Lacroix, Monique; Serre, Laurence; Teillet, Florence; Arlaud, Gérard J; Rossi, Véronique; Thielens, Nicole M

2013-01-01

418

Serine residue 45 of nodulation protein NodF from Rhizobium leguminosarum bv. viciae is essential for its biological function.  

PubMed

A system for testing the role of the Rhizobium nodF gene in the production of host-specific lipochitin oligosaccharides and in nodulation was developed. We show that a mutant nodF gene, in which the codon for serine residue 45 was changed to that for threonine, still expresses NodF, which, however, is no longer functional. PMID:8002602

Ritsema, T; Geiger, O; van Dillewijn, P; Lugtenberg, B J; Spaink, H P

1994-12-01

419

Production of L-DOPA from pyrocatechol and DL-serine by bioconversion using immobilized Erwinia herbicola cells  

Microsoft Academic Search

Immobilized cells of Erwinia herbicola were used for L-DOPA production from pyrocatechol and DL-serine. Optimal conditions have been defined and utilized in batch and continuous reactors. A maximal volumetric productivity of 0.46 g\\/l.h in L-DOPA was obtained with a conversion yield of 18% (L-DOPA concentration 2.3 g\\/l).

G. Para; S. Rifai; J. Baratti

1984-01-01

420

Serine/Threonine Phosphatase Stp1 Mediates Post-transcriptional Regulation of Hemolysin, Autolysis, and Virulence of Group B Streptococcus*  

PubMed Central

Elucidating how serine/threonine phosphatases regulate kinase function and bacterial virulence is critical for our ability to combat these infections. Group B streptococci (GBS) are ?-hemolytic Gram-positive bacteria that cause invasive infections in humans. To adapt to environmental changes, GBS encodes signaling mechanisms comprising two component systems and eukaryotic-like enzymes. We have previously described the importance of the serine/threonine kinase Stk1 to GBS pathogenesis. However, how the presence or absence of the cognate serine/threonine phosphatase Stp1 affects Stk1 function and GBS virulence is not known. Here, we show that GBS deficient only in Stp1 expression are markedly reduced for their ability to cause systemic infections, exhibit decreased ?-hemolysin/cytolysin activity, and show increased sensitivity to autolysis. Although transcription of genes important for ?-hemolysin/cytolysin expression and export is similar to the wild type (WT), 294 genes (excluding stp1) showed altered expression in the stp1 mutant and included autolysin genes. Furthermore, phosphopeptide enrichment analysis identified that 35 serine/threonine phosphopeptides, corresponding to 27 proteins, were unique to the stp1 mutant. This included phosphorylation of ATP synthase, DNA and RNA helicases, and proteins important for cell division and protein synthesis. Collectively, our results indicate that Stp1 is important for appropriate regulation of Stk1 function, hemolysin activity, autolysis, and GBS virulence. PMID:22081606

Burnside, Kellie; Lembo, Annalisa; Harrell, Maria Isabel; Gurney, Michael; Xue, Liang; BinhTran, Nguyen-Thao; Connelly, James E.; Jewell, Kelsea A.; Schmidt, Byron Z.; de los Reyes, Melissa; Tao, Weiguo Andy; Doran, Kelly S.; Rajagopal, Lakshmi

2011-01-01

421

barren inflorescence2 Encodes a Co-Ortholog of the PINOID Serine/Threonine Kinase and Is Required for  

E-print Network

barren inflorescence2 Encodes a Co-Ortholog of the PINOID Serine/Threonine Kinase and Is Required for Organogenesis during Inflorescence and Vegetative Development in Maize1[C][W][OA] Paula McSteen*, Simon) and rice (Oryza sativa) have additional types of axillary meristems in the inflorescence compared

Malcomber, Simon

422

Bacillus thuringiensis Cry3Aa protoxin intoxication of Tenebrio molitor induces widespread changes in the expression of serine peptidase transcripts  

Technology Transfer Automated Retrieval System (TEKTRAN)

The yellow mealworm, Tenebrio molitor, is a pest of stored grain products and is sensitive to the coleopteran-specific Cry3Aa toxin from Bacillus thuringiensis (Bt). Larvae digest protein initially with cysteine peptidases in the anterior midgut and further with serine peptidases in middle and poste...

423

The Physarum polycephalum php gene encodes a unique cold-adapted serine-carboxyl peptidase, physarolisin II  

Microsoft Academic Search

The php gene from a true slime mold, Physarum polycephalum, is a late-replicating and transcriptionally active gene. The deduced amino acid sequence of the gene product is homologous to those of the serine-carboxyl peptidase family, including physarolisin I from the same organism, but lacks the propeptide region. In this study, the protein was expressed in Escherichia coli and shown to

Wataru Nishii; Hiroki Kuriyama; Kenji Takahashi

2003-01-01

424

Serine protease HtrA1 accumulates in corneal transforming growth factor beta induced protein (TGFBIp) amyloid deposits  

PubMed Central

Purpose Specific mutations in the transforming growth factor beta induced (TGFBI) gene are associated with lattice corneal dystrophy (LCD) type 1 and its variants. In this study, we performed an in-depth proteomic analysis of human corneal amyloid deposits associated with the heterozygous A546D mutation in TGFBI. Methods Corneal amyloid deposits and the surrounding corneal stroma were procured by laser capture microdissection from a patient with an A546D mutation in TGFBI. Proteins in the captured corneal samples and healthy corneal stroma were identified with liquid chromatography-tandem mass spectrometry and quantified by calculating exponentially modified Protein Abundance Index values. Mass spectrometry data were further compared for identifying enriched regions of transforming growth factor beta induced protein (TGFBIp/keratoepithelin/?ig-h3) and detecting proteolytic cleavage sites in TGFBIp. Results A C-terminal fragment of TGFBIp containing residues Y571-R588 derived from the fourth fasciclin 1 domain (FAS1–4), serum amyloid P-component, apolipoprotein A-IV, clusterin, and serine protease HtrA1 were significantly enriched in the amyloid deposits compared to the healthy cornea. The proteolytic cleavage sites in TGFBIp from the diseased cornea are in accordance with the activity of serine protease HtrA1. We also identified small amounts of the serine protease kallikrein-14 in the amyloid deposits. Conclusions Corneal amyloid caused by the A546D mutation in TGFBI involves several proteins associated with other varieties of amyloidosis. The proteomic data suggest that the sequence 571-YHIGDEILVSGGIGALVR-588 contains the amyloid core of the FAS1–4 domain of TGFBIp and point at serine protease HtrA1 as the most likely candidate responsible for the proteolytic processing of amyloidogenic and aggregated TGFBIp, which explains the accumulation of HtrA1 in the amyloid deposits. With relevance to identifying serine proteases, we also found glia-derived nexin (protease-nexin 1) in the amyloid deposits, making this serine protease inhibitor a good candidate for the physiologically relevant inhibitor of one of the amyloid-associated serine proteases in the cornea and probably in other tissues. Noteworthy, the present results are in accordance with our findings from a previous study of corneal amyloid deposits caused by the V624M mutation in TGFBI, suggesting a common mechanism for lattice corneal dystrophies (LCDs) associated with mutations in the TGFBIp FAS1–4 domain. PMID:23592924

Karring, Henrik; Poulsen, Ebbe Toftgaard; Runager, Kasper; Thøgersen, Ida B.; Klintworth, Gordon K.; Højrup, Peter

2013-01-01

425

Age-related loss of phospholipid asymmetry in APP NLh \\/APP NLh x PS1 P264L \\/PS1 P264L human double mutant knock-in mice: Relevance to Alzheimer disease  

Microsoft Academic Search

Using APPNLh\\/APPNLh x PS-1P246L\\/PS-1P246L human double knock-in (APP\\/PS-1) mice, we examined whether phosphatidylserine (PtdSer) asymmetry is significantly altered in brain of this familial Alzheimer disease mouse model in an age-dependent manner as a result of oxidative stress, toxic A?(1-42) oligomer production, and\\/or apoptosis. Annexin V (AV) and NBD-PS fluorescence in synaptosomes of wild-type (WT) and APP\\/PS-1 mice were used to

Miranda L. Bader Lange; Daret St. Clair; William R. Markesbery; Christa M. Studzinski; M. Paul Murphy; D. Allan Butterfield

2010-01-01

426

Serine phosphorylation differentially affects RhoA binding to effectors: implications to NGF-induced neurite outgrowth.  

PubMed

Activation of RhoA prevents NGF-induced outgrowth and causes retraction of neurites in neuronal cells, including PC12 cells. Despite its inhibitory effect on neurite outgrowth, NGF activates GTP loading of and effector binding to RhoA, setting up an apparent contradiction. According to the molecular switch hypothesis of GTPase function GTP-loading of RhoA should be sufficient to activate its effectors uniformly. However, when monitoring NGF-induced binding of GTP-RhoA to multiple targets, we noted differential interactions with its effectors. We found that NGF elicits a protein kinase A-mediated phosphorylation of RhoA on serine(188), which renders it unable to bind to Rho-associated kinase (ROK), whereas it retains the ability to interact with other RhoA targets including rhotekin, mDia-1 and PKN. We show in vitro and in vivo that phosphorylation of serine(188) represents an additional switch, capable of directing signals among effector pathways. In the context of PC12 cell differentiation, NGF-induced phosphorylation of RhoA on serine(188) prevents it from interacting with ROK, which would otherwise block neurite outgrowth. Transfection of RhoA(S188A) mutant into PC12 cells prevents NGF-induced neurite outgrowth, just like constitutively activated RhoA(14V) does, indicating the requirement of this phosphorylation site. Replacement of serine(188) with the phosphomimetic glutamate residue in RhoA(V14/S188E) selectively impairs interaction with ROK and when transfected into PC12 cells restores NGF-induced neurite outgrowth. Therefore, phosphorylation of serine(188) may serve as a novel secondary switch of RhoA capable of overriding GTP-binding-elicited effector activation to a subset of targets such as ROK, which interact with the C-terminus of RhoA. PMID:16109481

Nusser, Nóra; Gosmanova, Elvira; Makarova, Natalia; Fujiwara, Yuko; Yang, Linda; Guo, Fukun; Luo, Yongneng; Zheng, Yi; Tigyi, Gábor

2006-05-01

427

Regulation of Insulin Receptor Substrate 1 Pleckstrin Homology Domain by Protein Kinase C: Role of Serine 24 Phosphorylation  

PubMed Central

Phosphorylation of insulin receptor substrate (IRS) proteins on serine residues is an important post-translational modification that is linked to insulin resistance. Several phosphoserine sites on IRS1 have been identified; the majority are located proximal to the phosphotryosine-binding domain or near key receptor tyrosine kinase substrate- and/or Src-homology 2 domain-binding sites. Here we report on the characterization of a serine phosphorylation site in the N-terminal pleckstrin homology (PH) domain of IRS1. Bioinformatic tools identify serine 24 (Ser24) as a putative substrate site for the protein kinase C (PKC) family of serine kinases. We demonstrate that this site is indeed a bona fide substrate for conventional PKC. In vivo, IRS-1 is also phosphorylated on Ser24 after phorbol 12-myristate 13-acetate treatment of cells, and isoform-selective inhibitor studies suggest the involvement of PKC?. By comparing the pharmacological characteristics of phorbol 12-myristate 13-acetate-stimulated Ser24 phosphorylation with phosphorylation at two other sites previously linked to PKC activity (Ser307 and Ser612), we show that PKC? is likely to be directly involved in Ser24 phosphorylation, but indirectly involved in Ser307 and Ser612 phosphorylation. Using Ser24Asp IRS-1 mutants to mimic the phosphorylated residue, we demonstrate that the phosphorylation status of Ser24 does play an important role in regulating phosphoinositide binding to, and the intracellular localization of, the IRS1-PH domain, which can ultimately impinge on insulin-stimulated glucose uptake. Hence we provide evidence that IRS1-PH domain function is important for normal insulin signaling and is regulated by serine phosphorylation in a manner that could contribute to insulin resistance. PMID:16574739

Nawaratne, Ranmali; Gray, Alexander; Jørgensen, Christina H.; Downes, C. Peter; Siddle, Kenneth; Sethi, Jaswinder K.

2015-01-01

428

Perceptions of Community Health Workers (CHWs/PS) in the U.S.-Mexico border HEART CVD study.  

PubMed

Although prior research has shown that Community Health Workers/Promotores de Salud (CHW/PS) can facilitate access to care, little is known about how CHW/PS are perceived in their community. The current study reports the findings of a randomized telephone survey conducted in a high-risk urban community environment along the U.S.-Mexico border. In preparation for a community-based CHW/PS intervention called the HEART ecological study, the survey aimed to assess perceptions of CHW/PS, availability and utilization of community resources (recreational and nutrition related) and health behaviors and intentions. A total of 7,155 calls were placed to complete 444 surveys in three zip codes in El Paso, Texas. Results showed that participants felt that healthful community resources were available, but utilization was low and variable: 35% reported going to a park, 20% reported having taken a health class, few reported using a gym (12%), recreation center (8%), or YMCA/YWCA (0.9%). Awareness and utilization of CHW/PS services were low: 20% of respondents had heard of CHW/PS, with 8% reporting previous exposure to CHW/PS services. Upon review of a definition of CHW/PS, respondents expressed positive views of CHW/PS and their value in the healthcare system. Respondents who had previous contact with a CHW/PS reported a significantly more positive perception of the usefulness of CHW/PS (p = 0.006), were more likely to see CHW/PS as an important link between providers and patients (p = 0.008), and were more likely to ask a CHW/PS for help (p = 0.009). Participants who utilized CHW/PS services also had significantly healthier intentions to reduce fast food intake. Future research is needed to evaluate if CHW/PS can facilitate utilization of available community resources such as recreational facilities among Hispanic border residents at risk for CVD. PMID:24518646

Balcazar, Hector G; Wise, Sherrie; Redelfs, Alisha; Rosenthal, E Lee; de Heer, Hendrik D; Burgos, Ximena; Duarte-Gardea, Maria

2014-02-01

429

7 CFR 1753.37 - Plans and specifications (P&S).  

Code of Federal Regulations, 2010 CFR

...proposal. (2) Guidelines for the preparation of the detailed equipment specifications are contained in the Telecommunications Engineering and Construction Manual (TE&CM), which is available from RUS. (c) RUS review of P&S is...

2010-01-01

430

7 CFR 1753.37 - Plans and specifications (P&S).  

...proposal. (2) Guidelines for the preparation of the detailed equipment specifications are contained in the Telecommunications Engineering and Construction Manual (TE&CM), which is available from RUS. (c) RUS review of P&S is...

2014-01-01

431

7 CFR 1753.37 - Plans and specifications (P&S).  

Code of Federal Regulations, 2012 CFR

...proposal. (2) Guidelines for the preparation of the detailed equipment specifications are contained in the Telecommunications Engineering and Construction Manual (TE&CM), which is available from RUS. (c) RUS review of P&S is...

2012-01-01

432

7 CFR 1753.37 - Plans and specifications (P&S).  

Code of Federal Regulations, 2011 CFR

...proposal. (2) Guidelines for the preparation of the detailed equipment specifications are contained in the Telecommunications Engineering and Construction Manual (TE&CM), which is available from RUS. (c) RUS review of P&S is...

2011-01-01

433

7 CFR 1753.37 - Plans and specifications (P&S).  

Code of Federal Regulations, 2013 CFR

...proposal. (2) Guidelines for the preparation of the detailed equipment specifications are contained in the Telecommunications Engineering and Construction Manual (TE&CM), which is available from RUS. (c) RUS review of P&S is...

2013-01-01

434

Research and optimization of the ESD response characteristic in a ps-LDMOS transistor  

NASA Astrophysics Data System (ADS)

The ESD response characteristic in a p-type symmetric lateral DMOS (ps-LDMOS) has been investigated. The experimental results show that the ps-LDMOS has weak ESD robustness due to an absence of the “snapback" characteristic. In addition, the location of the hot spot changes little for the special device. The method for reducing the lattice temperature of the hot spot can be used to enhance the ESD capacity of the ps-LDMOS, thereby, a novel and easily-achievable ps-LDMOS structure with a p-type lightly doped drain (p-LDD) has been proposed. The special region p-LDD lowers the electric field at the edge of the poly gate, making the whole distribution of the surface electric field more uniform. Therefore, the ESD robustness is improved two times and no obvious change of other electric parameters is introduced.

Hao, Wang; Siyang, Liu; Weifeng, Sun; Tingting, Huang

2014-01-01

435

2. P.S. Rittermann, Photographer February 1995 BUILDING 990, WEST SIDE. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. P.S. Rittermann, Photographer February 1995 BUILDING 990, WEST SIDE. - Presidio of San Francisco, Flammable Storage Building Submarine Mine Depot, Fort Point vicinity, Long Avenue, San Francisco, San Francisco County, CA

436

78 FR 64603 - Medicare Program: Conditions of Participation (CoPs) for Community Mental Health Centers  

Federal Register 2010, 2011, 2012, 2013

...October 29, 2013 Part II Department of Health and Human Services...Participation (CoPs) for Community Mental Health Centers; Final Rule Federal Register...DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for...

2013-10-29