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Sample records for surface phosphatase activities

  1. Surface-bound phosphatase activity in living hyphae of ectomycorrhizal fungi of Nothofagus obliqua.

    Science.gov (United States)

    Alvarez, Maricel; Godoy, Roberto; Heyser, Wolfgang; Härtel, Steffen

    2004-01-01

    We determined the location and the activity of surface-bound phosphomonoesterase (SBP) of five ectomycorrhizal (EM) fungi of Nothofagus oblique. EM fungal mycelium of Paxillus involutus, Austropaxillus boletinoides, Descolea antartica, Cenococcum geophilum and Pisolithus tinctorius was grown in media with varying concentrations of dissolved phosphorus. SBP activity was detected at different pH values (3-7) under each growth regimen. SBP activity was assessed using a colorimetric method based on the hydrolysis of p-nitrophenyl phosphate (pNPP) to p-nitrophenol phosphate (pNP) + P. A new technique involving confocal laser-scanning microscopy (LSM) was used to locate and quantify SBP activity on the hyphal surface. EM fungi showed two fundamentally different patterns of SBP activity in relation to varying environmental conditions (P-concentrations and pH). In the cases of D. antartica, A. boletinoides and C. geophilum, changes in SBP activity were induced primarily by changes in the number of SBP-active centers on the hyphae. In the cases of P. tinctorius and P. involutus, the number of SBP-active centers per μm hyphal length changed much less than the intensity of the SBP-active centers on the hyphae. Our findings not only contribute to the discussion about the role of SBP-active centers in EM fungi but also introduce LSM as a valuable method for studying EM fungi.

  2. Separation of pig bone alkaline phosphatase activities.

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    Leunis, J C; Vancraeynest, T; Brauman, J

    1977-01-01

    A simple method for the separation of alkaline phosphatase and pyrophosphatase activities of pig bone ribs is described. Using anionic exchange chromatography (DEAE-cellulose) and affinity chromatography on Concanavalin A sepharose (Con A) eluted by a step pH gradient and Na4P2O7, several activities were obtained. A pyrophosphatase containing very little alkaline phosphatase activity was isolated from Con A sepharose by elution with pyrophosphatase. Our data are consistent, with the hypothesis that cortical alcaline phosphatase and pyrophosphatase activities are not due to a single enzyme protein. The method was used on whole bone, on bone marrow and on cortical bone.

  3. Specific activity of cell-surface acid phosphatase in different bacterioplankton morphotypes in an acidified mountain lake

    Czech Academy of Sciences Publication Activity Database

    Nedoma, Jiří; Vrba, Jaroslav

    2006-01-01

    Roč. 8, č. 7 (2006), s. 1271-1279 ISSN 1462-2912 R&D Projects: GA AV ČR(CZ) IAA6017202 Institutional research plan: CEZ:AV0Z60170517 Keywords : alkaline phosphatase * bacterial morphorypes * acidified lake Subject RIV: CE - Biochemistry Impact factor: 4.630, year: 2006

  4. Changes of Available Phosphorus and phosphatase activity in the ...

    African Journals Online (AJOL)

    There were significant differences between phosphatase activities in rhizosphere of plant species. The highest and lowest means of alkaline phosphatase activity were found in rhizosphere of Trifolium repens and. Ocimum basilicum respectively. The highest and lowest means of acid phosphatase activity were found in ...

  5. Email Changes of Available Phosphorus and phosphatase activity in ...

    African Journals Online (AJOL)

    MICHAEL

    by depletion of Pi. There were significant differences between phosphatase activities in rhizosphere of plant species. The highest and lowest means of alkaline phosphatase activity were found in rhizosphere of Trifolium repens and. Ocimum basilicum respectively. The highest and lowest means of acid phosphatase activity ...

  6. Direct determination of phosphatase activity from physiological substrates in cells.

    Directory of Open Access Journals (Sweden)

    Zhongyuan Ren

    Full Text Available A direct and continuous approach to determine simultaneously protein and phosphate concentrations in cells and kinetics of phosphate release from physiological substrates by cells without any labeling has been developed. Among the enzymes having a phosphatase activity, tissue non-specific alkaline phosphatase (TNAP performs indispensable, multiple functions in humans. It is expressed in numerous tissues with high levels detected in bones, liver and neurons. It is absolutely required for bone mineralization and also necessary for neurotransmitter synthesis. We provided the proof of concept that infrared spectroscopy is a reliable assay to determine a phosphatase activity in the osteoblasts. For the first time, an overall specific phosphatase activity in cells was determined in a single step by measuring simultaneously protein and substrate concentrations. We found specific activities in osteoblast like cells amounting to 116 ± 13 nmol min(-1 mg(-1 for PPi, to 56 ± 11 nmol min(-1 mg(-1 for AMP, to 79 ± 23 nmol min(-1 mg(-1 for beta-glycerophosphate and to 73 ± 15 nmol min(-1 mg(-1 for 1-alpha-D glucose phosphate. The assay was also effective to monitor phosphatase activity in primary osteoblasts and in matrix vesicles. The use of levamisole--a TNAP inhibitor--served to demonstrate that a part of the phosphatase activity originated from this enzyme. An IC50 value of 1.16 ± 0.03 mM was obtained for the inhibition of phosphatase activity of levamisole in osteoblast like cells. The infrared assay could be extended to determine any type of phosphatase activity in other cells. It may serve as a metabolomic tool to monitor an overall phosphatase activity including acid phosphatases or other related enzymes.

  7. Fluorescence quenching based alkaline phosphatase activity detection.

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    Mei, Yaqi; Hu, Qiong; Zhou, Baojing; Zhang, Yonghui; He, Minhui; Xu, Ting; Li, Feng; Kong, Jinming

    2018-01-01

    Simple and fast detection of alkaline phosphatase (ALP) activity is of great importance for diagnostic and analytical applications. In this work, we report a turn-off approach for the real-time detection of ALP activity on the basis of the charge transfer induced fluorescence quenching of the Cu(BCDS) 2 2- (BCDS = bathocuproine disulfonate) probe. Initially, ALP can enzymatically hydrolyze the substrate ascorbic acid 2-phosphate to release ascorbic acid (AA). Subsequently, the AA-mediated reduction of the Cu(BCDS) 2 2- probe, which displays an intense photoluminescence band at the wavelength of 402nm, leads to the static quenching of fluorescence of the probe as a result of charge transfer. The underlying mechanism of the fluorescence quenching was demonstrated by quantum mechanical calculations. The Cu(BCDS) 2 2- probe features a large Stokes shift (86nm) and is highly immune to photo bleaching. In addition, this approach is free of elaborately designed fluorescent probes and allows the detection of ALP activity in a real-time manner. Under optimal conditions, it provides a fast and sensitive detection of ALP activity within the dynamic range of 0-220mUmL -1 , with a detection limit down to 0.27mUmL -1 . Results demonstrate that it is highly selective, and applicable to the screening of ALP inhibitors in drug discovery. More importantly, it shows a good analytical performance for the direct detection of the endogenous ALP levels of undiluted human serum and even whole blood samples. Therefore, the proposed charge transfer based approach has great potential in diagnostic and analytical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. [Radiation-induced changes of skin enzyme activity. II. Acid phosphatase, alkaline phosphatase].

    Science.gov (United States)

    Báthori, E; Soltész, L

    1975-05-01

    After application of solf X-rays with 100, 500 and 1000 R, the activity change of the acid and alcaline phosphatase in the skin of mice has been studied. The studies happened immediatly after the irradiation and at the 1st, 2nd, 4th, 8th and 16th day. The measurment of the enzyme activity washable out of the skin and remianing in the skin after the washing and the total activity of the skin have been taken up. With the acid phosphatase it would be determined that the quantity washable out of the skin is unusually low; the acitity values of the wash solution increase at the 2nd day after the irradiation in dependence on the applicated dose;at the moment 0 after an irradiation with 1000 R, a significative activity increase in the wash solution appears; the homogenate activity at the 2nd day only gets a significative activity increase after the irradiation with 500 R. The alcaline phosphatase was measurable in the wash solution at no moment of the measurement. However, the alcaline phosphatase has been decreased in the homogenate with few exceptions.

  9. Detection of phosphatase activity in aquatic and terrestrial cyanobacterial strains

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    Babić Olivera B.

    2013-01-01

    Full Text Available Cyanobacteria, as highly adaptable microorganisms, are characterized by an ability to survive in different environmental conditions, in which a significant role belongs to their enzymes. Phosphatases are enzymes produced by algae in relatively large quantities in response to a low orthophosphate concentration and their activity is significantly correlated with their primary production. The activity of these enzymes was investigated in 11 cyanobacterial strains in order to determine enzyme synthesis depending on taxonomic and ecological group of cyanobacteria. The study was conducted with 4 terrestrial cyanobacterial strains, which belong to Nostoc and Anabaena genera, and 7 filamentous water cyanobacteria of Nostoc, Oscillatoria, Phormidium and Microcystis genera. The obtained results showed that the activity of acid and alkaline phosphatases strongly depended on cyanobacterial strain and the environment from which the strain originated. Higher activity of alkaline phosphatases, ranging from 3.64 to 85.14 μmolpNP/s/dm3, was recorded in terrestrial strains compared to the studied water strains (1.11-5.96 μmolpNP/s/dm3. The activity of acid phosphatases was higher in most tested water strains (1.67-6.28 μmolpNP/s/dm3 compared to the activity of alkaline phosphatases (1.11-5.96 μmolpNP/s/dm3. Comparing enzyme activity of nitrogen fixing and non-nitrogen fixing cyanobacteria, it was found that most nitrogen fixing strains had a higher activity of alkaline phosphatases. The data obtained in this work indicate that activity of phosphatases is a strain specific property. The results further suggest that synthesis and activity of phosphatases depended on eco-physiological characteristics of the examined cyanobacterial strains. This can be of great importance for the further study of enzymes and mechanisms of their activity as a part of cyanobacterial survival strategy in environments with extreme conditions. [Projekat Ministarstva nauke Republike

  10. Nature of immobilization surface affects antibody specificity to placental alkaline phosphatase.

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    Kumar, Mukesh; Khan, Imran; Sinha, Subrata

    2015-01-01

    Retention of native conformation of immobilized protein is essential for various applications including selection and detection of specific recombinant antibodies (scFvs). Placental alkaline phosphatase (PAP), an onco-fetal antigen expressed on the surface of several tumors, was immobilized on supermagnetic particles for selection of recombinant antibodies from a human phage display antibody library. The isolated antibodies were found to be cross-reactive to either of the isozymes of alkaline phosphatase, i.e., bone alkaline phosphatase (BAP) or intestinal alkaline phosphatase (IAP) and could not be used for tumor targeting. A specific anti-PAP monoclonal antibody H17E2 was tested for retention of specificity under these conditions. Binding of the antibody to magnetic beads conjugated IAP and BAP along with PAP and the ability of the two isozymes to inhibit its binding to PAP depicted the loss of isozyme specificity of the antibody. However, the antibody retained its specificity to PAP immobilized on polyvinyl chloride (PVC) surface. Enzyme activity was observed on both surfaces. This demonstrates that nature of immobilization may affect antigen-antibody binding in subtle ways, resulting in alteration of conformation of the epitopes. This may have consequences for determining the specificity of antibody binding for proteins that share a high degree of homology.

  11. [Studies On Phosphatase Activity In Some Parasitic Helminths

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    Park, Chung Jai; Seo, Byong Seol

    1967-12-01

    In order to obtain some informations on the nature and relative activity of the phosphatases present in various helminths, biochemical studies have been made in thirteen kinds of worm parasites including the adults and larvae (Fasciola hepatica, Eurytrema pancreaticum, Paramphistomum sp., Taenia solium, Taenia pisiformis, Dipylidium caninum, Diphyllobothrium mansoni, Cysticercus cellulosae, Cysticercus fasciolaris and Sparganum). A comparison based on the analysis of pH-activity curves was made among these helminths. The worm materials were mostly obtained alive from an abattoir and removed from the organs or tissues of the animal hosts naturally infected. Sparganum and Cysticercus cellulosae, however, are collected from the subcutaneous tissue of the patients by surgical removal. The worms thoroughly washed were weighed and transferred with 0.1 M Tris buffer to a chilled glass grinder (Capacity; 15 ml) and homogenized in the cold. The homogenate was centrifuged at 5000 RPM for 30 minutes. The supernatant was pipetted off for determination of the phosphatase activity. Incubation mixtures consisted of 1 ml substrate, 1 ml buffer and 0.5ml extract. The buffers used were Tris (Hydroxymethyl) aminomethane and citric acid monohydrate and the substrate was paranitrophenyl phosphate (1 gm/25 ml). These mixtures were incubated at the temperature of 37 degrees C for 30 minutes in water bath. The absorbance or transferance of mixture was determined colorimetrically by "Spectronic 20 "spectrophotometer at 410 nm against a distilled water blank. The amount of phenol liberated was then calculated from a standard curve using phenol solutions. Controls consisted of unincubated mixtures. The results were deducted from this experiment. The phosphatase activity occurred over all parasitic helminths used in this experiment. In trematodes, pH-activity curves have demonstrated two peaks of phosphatase activity in Fasciola hepatica and Paramphistomum species. However the acid

  12. Metals in the active site of native protein phosphatase-1.

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    Heroes, Ewald; Rip, Jens; Beullens, Monique; Van Meervelt, Luc; De Gendt, Stefan; Bollen, Mathieu

    2015-08-01

    Protein phosphatase-1 (PP1) is a major protein Ser/Thr phosphatase in eukaryotic cells. Its activity depends on two metal ions in the catalytic site, which were identified as manganese in the bacterially expressed phosphatase. However, the identity of the metal ions in native PP1 is unknown. In this study, total reflection X-ray fluorescence (TXRF) was used to detect iron and zinc in PP1 that was purified from rabbit skeletal muscle. Metal exchange experiments confirmed that the distinct substrate specificity of recombinant and native PP1 is determined by the nature of their associated metals. We also found that the iron level associated with native PP1 is decreased by incubation with inhibitor-2, consistent with a function of inhibitor-2 as a PP1 chaperone. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Haemoglobin and Lung Total and Lysosomal Phosphatase Activity ...

    African Journals Online (AJOL)

    Comparisons were made of the effect of Benson & Hedges cigarette (filter-tipped) and Captain Black cigar (Non filter-tipped) smoke on rat plasma haemoglobin, carboxy-haemoglobin and nicotine levels, average body weight and daily feed intake, lung Total and lysosomal acid phosphatase activity. The results showed that ...

  14. Determination of Cancer Cell-Based pH-Sensitive Fluorescent Carbon Nanoparticles of Cross-Linked Polydopamine by Fluorescence Sensing of Alkaline Phosphatase Activity on Coated Surfaces and Aqueous Solution.

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    Kang, Eun Bi; Choi, Cheong A; Mazrad, Zihnil Adha Islamy; Kim, Sung Han; In, Insik; Park, Sung Young

    2017-12-19

    The tumor-specific sensitive fluorescence sensing of cellular alkaline phosphatase (ALP) activity on the basis of host-guest specific and pH sensitivity was conducted on coated surfaces and aqueous states. Cross-linked fluorescent nanoparticles (C-FNP) consisting of β-cyclodextrin (β-CD)/boronic acid (BA) and fluorescent hyaluronic acid [FNP(HA)] were conjugated to fluorescent polydopamine [FNP(pDA)]. To determine the quenching effect of this system, hydrolysis of 4-nitrophenyl phosphate (NPP) to 4-nitrophenol (NP) was performed in the cavity of β-CD in the presence of ALP activated photoinduced electron transfer (PET) between NP and C-FNP. At an ALP level of 30-1000 U/L, NP caused off-emission of C-FNP because of their specific host-guest recognition. Fluorescence can be recovered under pH shock due to cleavage of the diol bond between β-CD and BA, resulting in release of NP from the fluorescent system. Sensitivity of the assays was assessed by confocal imaging not only in aqueous states, but also for the first time on coated surfaces in MDAMB-231 and MDCK cells. This novel system demonstrated high sensitivity to ALP through generation of good electron donor/acceptor pair during the PET process. Therefore, this fluorescence sensor system can be used to enhance ALP monitoring and cancer diagnosis on both coated surfaces and in aqueous states in clinical settings.

  15. [Alkaline phosphatase activity and properties in the organs of cattle and sheep].

    Science.gov (United States)

    Antonov, S

    1979-01-01

    Alkaline-phosphatase activity and the physico-chemical properties of the liver, lung, spleen, kidney, intestine, bone and placenta of 25 clinically healthy cattle and 30 clinically healthy sheep were investigated. High alkaline phosphatase activity was detected in kidneys and intestines. The alcaline phosphatase of cattle and sheep liver, spleen, kidney, lung, bone and placenta was thermo-labile and sensitive to l-arginine, l-homoarginine and imidazole, but was not sensitive to l-phenylalanine. Bone phosphatase of cattle and sheep was sensitive to urea. Intestinal phosphatase of cattle proved thermostable, sensitive to l-phenylalanine and not sensitive to l-arginine, l-homoarginine, imidasol and urea. Agarose gel electrophoresis of alkaline phosphatase indicated the presence of one fraction only and liver alkaline phosphatase proved to be the fastest. Sheep liver alkaline phosphatase had two fractions while sheep intestinal and placental alkaline phosphatase had three fractions and some of them were faster than liver alkaline phosphatase.

  16. Phosphatase activity tunes two-component system sensor detection threshold.

    Science.gov (United States)

    Landry, Brian P; Palanki, Rohan; Dyulgyarov, Nikola; Hartsough, Lucas A; Tabor, Jeffrey J

    2018-04-12

    Two-component systems (TCSs) are the largest family of multi-step signal transduction pathways in biology, and a major source of sensors for biotechnology. However, the input concentrations to which biosensors respond are often mismatched with application requirements. Here, we utilize a mathematical model to show that TCS detection thresholds increase with the phosphatase activity of the sensor histidine kinase. We experimentally validate this result in engineered Bacillus subtilis nitrate and E. coli aspartate TCS sensors by tuning their detection threshold up to two orders of magnitude. We go on to apply our TCS tuning method to recently described tetrathionate and thiosulfate sensors by mutating a widely conserved residue previously shown to impact phosphatase activity. Finally, we apply TCS tuning to engineer B. subtilis to sense and report a wide range of fertilizer concentrations in soil. This work will enable the engineering of tailor-made biosensors for diverse synthetic biology applications.

  17. Characterization of acid phosphatase activities in the equine pathogen Streptococcus equi.

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    Hamilton, A; Harrington, D; Sutcliffe, I C

    2000-10-01

    Acid phosphatases hydrolyse phosphomonoesters at acidic pH in a variety of physiological contexts. The recently defined class C family of acid phosphatases includes the 32 kDa LppC lipoprotein of Streptococcus equisimilis. To define further the distribution of acid phosphatases in the genus Streptococcus we have examined the equine pathogens Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus. Whole cell assays indicated that these organisms possess two acid phosphatases with activity optima at pH 5.0 and pH 6.0-6.5 and that only the former of these was, like LppC, resistant to EDTA. Western blotting with a polyclonal anti-LppC antiserum revealed the presence of a cross-reactive 32 kDa protein in both organisms. The cross-reactive protein in S. equi was shown to be a surface accessible lipoprotein as its processing was inhibited by the antibiotic globomycin and it was released from whole cells by treatment with trypsin. The presence of DNA sequences homologous to the S. equisimilis lppC gene were confirmed by PCR. These data strongly suggest that Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus produce a lipoprotein acid phosphatase homologous to LppC of S. equisimilis.

  18. ALKALINE PHOSPHATASE ACTIVITY AS A MARKER OF DOG SEMEN FREEZABILITY

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    KOSINIAK-KAMYSZ K.

    2007-01-01

    Full Text Available The investigation was performed to evaluate the dog semen freezability and itsquality after thawing allowing its use for artificial insemination (AI. On the basis ofsperm motility, concentration and alkaline phosphatase (AP activity in semenplasma it was possible to establish that AP activity corresponds with the basic factorof semen examination. Significant statistical differences occurred between thequality of ejaculates which were qualified or disqualified to deep freezing and AI.These results show that AP activity in raw dog semen plasma can be used as amarker for the dog semen qualification for deep freezing and AI with 95%probability of the prognosis of the results.

  19. ALKALINE PHOSPHATASE ACTIVITY AS A MARKER OF DOG SEMEN FREEZABILITY

    Directory of Open Access Journals (Sweden)

    K. KOSINIAK-KAMYSZ

    2007-05-01

    Full Text Available The investigation was performed to evaluate the dog semen freezability and itsquality after thawing allowing its use for artificial insemination (AI. On the basis ofsperm motility, concentration and alkaline phosphatase (AP activity in semenplasma it was possible to establish that AP activity corresponds with the basic factorof semen examination. Significant statistical differences occurred between thequality of ejaculates which were qualified or disqualified to deep freezing and AI.These results show that AP activity in raw dog semen plasma can be used as amarker for the dog semen qualification for deep freezing and AI with 95%probability of the prognosis of the results.

  20. The protein phosphatase activity of PTEN is essential for regulating neural stem cell differentiation.

    Science.gov (United States)

    Lyu, Jingwen; Yu, Xiuya; He, Lingjie; Cheng, Tianlin; Zhou, Jingjing; Cheng, Cheng; Chen, Zhifang; Cheng, Guoqiang; Qiu, Zilong; Zhou, Wenhao

    2015-04-18

    The tumor suppressor gene Phosphatase and tensin homolog (PTEN) is highly expressed in neural progenitor cells (NPCs) and plays an important role in development of the central nervous system. As a dual-specificity phosphatase, the loss of PTEN phosphatase activity has been linked to various diseases. Here we report that the protein phosphatase activity of Pten is critical for regulating differentiation of neural progenitor cells. First we found that deletion of Pten promotes neuronal differentiation. To determine whether the protein or lipid phosphatase activity is required for regulating neuronal differentiation, we generated phosphatase domain-specific Pten mutations. Interestingly, only expression of protein phosphatase-deficient mutant Y138L could mimic the effect of knocking down Pten, suggesting the protein phosphatase of Pten is critical for regulating NPC differentiation. Importantly, we showed that the wild-type and lipid phosphatase mutant (G129E) forms of Pten are able to rescue neuronal differentiation in Pten knockout NPCs, but mutants containing protein phosphatase mutant cannot. We further found that Pten-dependent dephosphorylation of CREB is critical for neuronal differentiation. Our data indicate that the protein phosphatase activity of PTEN is critical for regulating differentiation of NSCs during cortical development.

  1. Differential Requirement for Pten Lipid and Protein Phosphatase Activity during Zebrafish Embryonic Development.

    Science.gov (United States)

    Stumpf, Miriam; den Hertog, Jeroen

    2016-01-01

    The lipid- and protein phosphatase PTEN is one of the most frequently mutated tumor suppressor genes in human cancers and many mutations found in tumor samples directly affect PTEN phosphatase activity. In order to understand the functional consequences of these mutations in vivo, the aim of our study was to dissect the role of Pten phosphatase activities during zebrafish embryonic development. As in other model organisms, zebrafish mutants lacking functional Pten are embryonically lethal. Zebrafish have two pten genes and pten double homozygous zebrafish embryos develop a severe pleiotropic phenotype around 4 days post fertilization, which can be largely rescued by re-introduction of pten mRNA at the one-cell stage. We used this assay to characterize the rescue-capacity of Pten and variants with mutations that disrupt lipid, protein or both phosphatase activities. The pleiotropic phenotype at 4dpf could only be rescued by wild type Pten, indicating that both phosphatase activities are required for normal zebrafish embryonic development. An earlier aspect of the phenotype, hyperbranching of intersegmental vessels, however, was rescued by Pten that retained lipid phosphatase activity, independent of protein phosphatase activity. Lipid phosphatase activity was also required for moderating pAkt levels at 4 dpf. We propose that the role of Pten during angiogenesis mainly consists of suppressing PI3K signaling via its lipid phosphatase activity, whereas the complex process of embryonic development requires lipid and protein phosphatase of Pten.

  2. Intraspecific variation in alkaline phosphatase activity in Phaeodactylum tricornutum (Bacillariophyceae, Bohlin

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    Domênica Teixeira de Lima

    2016-01-01

    Full Text Available ABSTRACT To describe potential intraspecific variation in phosphorus incorporation in two strains of Phaeodactylum tricornutum (Bohlin, Ub3 and Ub7, alkaline phosphatase (AP activity was evaluated via enzyme-labeled fluorescence assay. Analysis using the probe ELF-97(r provides individual evaluation, and therefore can determine the nutritional status of inorganic phosphorus in phytoplanktonic cells. Bioassays compared the control treatment to both phosphate-enriched and phosphate-depleted treatments by varying only the phosphate concentration in the media. The P. tricornutum strains exhibited differences in their development when incubated in the phosphate-enriched media. The development of the Ub7 strain differed by exhibiting "luxury uptake" and utilization of organic phosphorus, and the alkaline phosphatase analysis indicated limitations of this clone under such conditions. The Ub7 strain showed higher AP activity, when compared to Ub3, in the P-enriched condition. P. tricornutum presented increases in AP activity and low variation in Surface/Volume ratio, by increasing biovolume and its maximum linear dimension, as strategies for phosphate incorporation. Our results highlight intraspecific differences in alkaline phosphatase activity, and hence differences in the incorporation of organic phosphorus, as the tested species regulated enzymatic activity under different external phosphate concentrations.

  3. From phosphatases to vanadium peroxidases: a similar architecture of the active site.

    Science.gov (United States)

    Hemrika, W; Renirie, R; Dekker, H L; Barnett, P; Wever, R

    1997-03-18

    We show here that the amino acid residues contributing to the active sites of the vanadate containing haloperoxidases are conserved within three families of acid phosphatases; this suggests that the active sites of these enzymes are very similar. This is confirmed by activity measurements showing that apochloroperoxidase exhibits phosphatase activity. These observations not only reveal interesting evolutionary relationships between these groups of enzymes but may also have important implications for the research on acid phosphatases, especially glucose-6-phosphatase-the enzyme affected in von Gierke disease-of which the predicted membrane topology may have to be reconsidered.

  4. Optimization of extraction parameters of PTP1? (protein tyrosine phosphatase 1?), inhibitory polyphenols, and anthocyanins from Zea mays L. using response surface methodology (RSM)

    OpenAIRE

    Hwang, Seung Hwan; Kwon, Shin Hwa; Wang, Zhiqiang; Kim, Tae Hyun; Kang, Young-Hee; Lee, Jae-Yong; Lim, Soon Sung

    2016-01-01

    Background Protein tyrosine phosphatase expressed in insulin-sensitive tissues (such as liver, muscle, and adipose tissue) has a key role in the regulation of insulin signaling and pathway activation, making protein tyrosine phosphatase a promising target for the treatment of type 2 diabetes mellitus and obesity and response surface methodology (RSM) is an effective statistical technique for optimizing complex processes using a multi-variant approach. Methods In this study, Zea mays L. (Purpl...

  5. Biomineralization of Uranium by PhoY Phosphatase Activity Aids Cell Survival in Caulobacter crescentus

    Energy Technology Data Exchange (ETDEWEB)

    Yung, M C [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jiao, Y [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-07-22

    Caulobacter crescentus is known to tolerate high levels of uranium [U(VI)], but its detoxification mechanism is poorly understood. Here we show that C. crescentus is able to facilitate U(VI) biomineralization through the formation of U-Pi precipitates via its native alkaline phosphatase activity. The U-Pi precipitates, deposited on the cell surface in the form of meta-autunite structures, have a lower U/Pi ratio than do chemically produced precipitates. The enzyme that is responsible for the phosphatase activity and thus the biomineralization process is identified as PhoY, a periplasmic alkaline phosphatase with broad substrate specificity. Furthermore, PhoY is shown to confer a survival advantage on C. crescentus toward U(VI) under both growth and nongrowth conditions. Results obtained in this study thus highlight U(VI) biomineralization as a resistance mechanism in microbes, which not only improves our understanding of bacterium-mineral interactions but also aids in defining potential ecological niches for metal-resistant bacteria.

  6. Imaging of alkaline phosphatase activity in bone tissue.

    Directory of Open Access Journals (Sweden)

    Terence P Gade

    Full Text Available The purpose of this study was to develop a paradigm for quantitative molecular imaging of bone cell activity. We hypothesized the feasibility of non-invasive imaging of the osteoblast enzyme alkaline phosphatase (ALP using a small imaging molecule in combination with (19Flourine magnetic resonance spectroscopic imaging ((19FMRSI. 6, 8-difluoro-4-methylumbelliferyl phosphate (DiFMUP, a fluorinated ALP substrate that is activatable to a fluorescent hydrolysis product was utilized as a prototype small imaging molecule. The molecular structure of DiFMUP includes two Fluorine atoms adjacent to a phosphate group allowing it and its hydrolysis product to be distinguished using (19Fluorine magnetic resonance spectroscopy ((19FMRS and (19FMRSI. ALP-mediated hydrolysis of DiFMUP was tested on osteoblastic cells and bone tissue, using serial measurements of fluorescence activity. Extracellular activation of DiFMUP on ALP-positive mouse bone precursor cells was observed. Concurringly, DiFMUP was also activated on bone derived from rat tibia. Marked inhibition of the cell and tissue activation of DiFMUP was detected after the addition of the ALP inhibitor levamisole. (19FMRS and (19FMRSI were applied for the non-invasive measurement of DiFMUP hydrolysis. (19FMRS revealed a two-peak spectrum representing DiFMUP with an associated chemical shift for the hydrolysis product. Activation of DiFMUP by ALP yielded a characteristic pharmacokinetic profile, which was quantifiable using non-localized (19FMRS and enabled the development of a pharmacokinetic model of ALP activity. Application of (19FMRSI facilitated anatomically accurate, non-invasive imaging of ALP concentration and activity in rat bone. Thus, (19FMRSI represents a promising approach for the quantitative imaging of bone cell activity during bone formation with potential for both preclinical and clinical applications.

  7. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Sobecky, Patricia A. [Univ. of Alabama, Tuscaloosa, AL (United States)

    2015-04-06

    In this project, inter-disciplinary research activities were conducted in collaboration among investigators at The University of Alabama (UA), Georgia Institute of Technology (GT), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), the DOE Joint Genome Institute (JGI), and the Stanford Synchrotron Radiation Light source (SSRL) to: (i) confirm that phosphatase activities of subsurface bacteria in Area 2 and 3 from the Oak Ridge Field Research Center result in solid U-phosphate precipitation in aerobic and anaerobic conditions; (ii) investigate the eventual competition between uranium biomineralization via U-phosphate precipitation and uranium bioreduction; (iii) determine subsurface microbial community structure changes of Area 2 soils following organophosphate amendments; (iv) obtain the complete genome sequences of the Rahnella sp. Y9-602 and the type-strain Rahnella aquatilis ATCC 33071 isolated from these soils; (v) determine if polyphosphate accumulation and phytate hydrolysis can be used to promote U(VI) biomineralization in subsurface sediments; (vi) characterize the effect of uranium on phytate hydrolysis by a new microorganism isolated from uranium-contaminated sediments; (vii) utilize positron-emission tomography to label and track metabolically-active bacteria in soil columns, and (viii) study the stability of the uranium phosphate mineral product. Microarray analyses and mineral precipitation characterizations were conducted in collaboration with DOE SBR-funded investigators at LBNL. Thus, microbial phosphorus metabolism has been shown to have a contributing role to uranium immobilization in the subsurface.

  8. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    International Nuclear Information System (INIS)

    Sobecky, Patricia A.

    2015-01-01

    In this project, inter-disciplinary research activities were conducted in collaboration among investigators at The University of Alabama (UA), Georgia Institute of Technology (GT), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), the DOE Joint Genome Institute (JGI), and the Stanford Synchrotron Radiation Light source (SSRL) to: (i) confirm that phosphatase activities of subsurface bacteria in Area 2 and 3 from the Oak Ridge Field Research Center result in solid U-phosphate precipitation in aerobic and anaerobic conditions; (ii) investigate the eventual competition between uranium biomineralization via U-phosphate precipitation and uranium bioreduction; (iii) determine subsurface microbial community structure changes of Area 2 soils following organophosphate amendments; (iv) obtain the complete genome sequences of the Rahnella sp. Y9-602 and the type-strain Rahnella aquatilis ATCC 33071 isolated from these soils; (v) determine if polyphosphate accumulation and phytate hydrolysis can be used to promote U(VI) biomineralization in subsurface sediments; (vi) characterize the effect of uranium on phytate hydrolysis by a new microorganism isolated from uranium-contaminated sediments; (vii) utilize positron-emission tomography to label and track metabolically-active bacteria in soil columns, and (viii) study the stability of the uranium phosphate mineral product. Microarray analyses and mineral precipitation characterizations were conducted in collaboration with DOE SBR-funded investigators at LBNL. Thus, microbial phosphorus metabolism has been shown to have a contributing role to uranium immobilization in the subsurface.

  9. Fluorescence labelling of phosphatase activity in digestive glands of carnivorous plants.

    Science.gov (United States)

    Płachno, B J; Adamec, L; Lichtscheidl, I K; Peroutka, M; Adlassnig, W; Vrba, J

    2006-11-01

    A new ELF (enzyme labelled fluorescence) assay was applied to detect phosphatase activity in glandular structures of 47 carnivorous plant species, especially Lentibulariaceae, in order to understand their digestive activities. We address the following questions: (1) Are phosphatases produced by the plants and/or by inhabitants of the traps? (2) Which type of hairs/glands is involved in the production of phosphatases? (3) Is this phosphatase production a common feature among carnivorous plants or is it restricted to evolutionarily advanced species? Our results showed activity of the phosphatases in glandular structures of the majority of the plants tested, both from the greenhouse and from sterile culture. In addition, extracellular phosphatases can also be produced by trap inhabitants. In Utricularia, activity of phosphatase was detected in internal glands of 27 species from both primitive and advanced sections and different ecological groups. Further positive reactions were found in Genlisea, Pinguicula, Aldrovanda, Dionaea, Drosera, Drosophyllum, Nepenthes, and Cephalotus. In Utricularia and Genlisea, enzymatic secretion was independent of stimulation by prey. Byblis and Roridula are usually considered as "proto-carnivores", lacking digestive enzymes. However, we found high activity of phosphatases in both species. Thus, they should be classified as true carnivores. We suggest that the inflorescence of Byblis and some Pinguicula species might also be an additional "carnivorous organ", which can trap a prey, digest it, and finally absorb available nutrients.

  10. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    Science.gov (United States)

    Martinez, R.; Wu, C. H.; Beazley, M. J.; Andersen, G. L.; Hazen, T. C.; Taillefert, M.; Sobecky, P. A.

    2011-12-01

    Soils and groundwater contaminated with heavy metals and radionuclides remain a legacy of Cold War nuclear weapons development. Due to the scale of environmental contamination, in situ sequestration of heavy metals and radionuclides remain the most cost-effective strategy for remediation. We are currently investigating a remediation approach that utilizes periplasmic and extracellular microbial phosphatase activity of soil bacteria capable promoting in situ uranium phosphate sequestration. Our studies focus on the contaminated soils from the DOE Field Research Center (ORFRC) in Oak Ridge, TN. We have previously demonstrated that ORFRC strains with phosphatase-positive phenotypes were capable of promoting the precpitation of >95% U(VI) as a low solubility phosphate mineral during growth on glycerol phosphate as a sole carbon and phosphorus source. Here we present culture-independent soil slurry studies aimed at understanding microbial community dynamics resulting from exogenous organophosphate additions. Soil slurries containing glycerol-2-phosphate (G2P) or glycerol-3-phosphate (G3P) and nitrate as the sole C, P and N sources were incubated under oxic growth conditions at pH 5.5 or pH 6.8. Following treatments, total DNA was extracted and prokaryotic diversity was assessed using high-density 16S oligonucleotide microarray (PhyloChip) analysis. Treatments at pH 5.5 and pH 6.8 amended with G2P required 36 days to accumulate 4.8mM and 2.2 mM phosphate, respectively. In contrast, treatments at pH 5.5 and pH 6.8 amended with G3P accumulated 8.9 mM and 8.7 mM phosphate, respectively, after 20 days. A total of 2120 unique taxa representing 46 phyla, 66 classes, 110 orders, and 186 families were detected among all treatment conditions. The phyla that significantly (P<0.05) increased in abundance relative to incubations lacking organophosphate amendments included: Crenarchaeota, Euryarchaeota, Bacteroidetes, and Proteobacteria. Members from the classes Bacteroidetes

  11. Uranium Biomineralization By Natural Microbial Phosphatase Activities in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Taillefert, Martial [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2015-04-01

    This project investigated the geochemical and microbial processes associated with the biomineralization of radionuclides in subsurface soils. During this study, it was determined that microbial communities from the Oak Ridge Field Research subsurface are able to express phosphatase activities that hydrolyze exogenous organophosphate compounds and result in the non-reductive bioimmobilization of U(VI) phosphate minerals in both aerobic and anaerobic conditions. The changes of the microbial community structure associated with the biomineralization of U(VI) was determined to identify the main organisms involved in the biomineralization process, and the complete genome of two isolates was sequenced. In addition, it was determined that both phytate, the main source of natural organophosphate compounds in natural environments, and polyphosphate accumulated in cells could also be hydrolyzed by native microbial population to liberate enough orthophosphate and precipitate uranium phosphate minerals. Finally, the minerals produced during this process are stable in low pH conditions or environments where the production of dissolved inorganic carbon is moderate. These findings suggest that the biomineralization of U(VI) phosphate minerals is an attractive bioremediation strategy to uranium bioreduction in low pH uranium-contaminated environments. These efforts support the goals of the SBR long-term performance measure by providing key information on "biological processes influencing the form and mobility of DOE contaminants in the subsurface".

  12. Differential requirement for pten lipid and protein phosphatase activity during zebrafish embryonic development

    NARCIS (Netherlands)

    Stumpf, Miriam; Den Hertog, Jeroen

    2016-01-01

    The lipid- and protein phosphatase PTEN is one of the most frequently mutated tumor suppressor genes in human cancers and many mutations found in tumor samples directly affect PTEN phosphatase activity. In order to understand the functional consequences of these mutations in vivo, the aim of our

  13. Cytoenzymologic activities of some oxidroeductases and alkaline phosphatase of leucocytes in Basedow, Cushing and Addison diseases.

    Science.gov (United States)

    Tasca, L; Onicescu, D

    1975-01-01

    Leukocytes, approached by histoenzymological methods for demonstration of dihydrofolate dehydrogenase, NADH2-diaphorase, lactate dehydrogenase and alcaline phosphatase activities, provided information about the impaired metabolic balance of thyrotoxicosis, Cushing and Addison diseases. The most relevant variations were found in thyrotoxicosis, the most sensitive enzyme was dihydrofolate dehydrogenase and the less sensitive was alcaline phosphatase. The neutrophils and lymphocytes had more evident enzymic variations.

  14. Stimulation of protein phosphatase activity by insulin and growth factors in 3T3 cells

    International Nuclear Information System (INIS)

    Chan, C.P.; McNall, S.J.; Krebs, E.G.; Fischer, E.H.

    1988-01-01

    Incubation of Swiss mouse 3T3-D1 cells with physiological concentrations of insulin resulted in a rapid and transient activation of protein phosphatase activity as measure by using [ 32 P]phosphorylase α as substrate. Activation reached a maximum level (140% of control value) within 5 min of addition and returned to control levels within 20 min. The effect of insulin was dose-dependent with half-maximal activation occurring at ∼5 nM insulin. This activity could be completely inhibited by addition of the heat-stable protein inhibitor 2, which suggests the presence of an activated type-1 phosphatase. Similar effects on phosphatase activity were seen when epidermal growth factor and platelet-derived growth factor were tested. These results suggest that some of the intracellular effects caused by insulin and growth factors are mediated through the activation of a protein phosphatase

  15. Alkaline phosphatase activity in salivary gland cells of Rhodnius neglectus and R. prolixus (Hemiptera, Triatominae).

    Science.gov (United States)

    Lima-Oliveira, A P M; Alevi, K C C; Anhê, A C B; Azeredo-Oliveira, M T V

    2016-07-29

    Alkaline phosphatase activity was detected in salivary gland cells of the Rhodnius neglectus Lent, 1954, and R. prolixus Stal, 1859, vectors of Trypanosoma cruzi Chagas, 1909 (etiological agent of Chagas disease) and T. rangeli Tejera, 1920 (pathogenic to insect). The Gomori technique was used to demonstrate alkaline phosphatase activity. Alkaline phosphatase activity was observed throughout the entire gland, with an increased activity in the posterior region of the principal gland. In particular, phosphatase activity was found in the nucleolar corpuscles, suggesting a relationship with the rRNA transcription and ribosomal biogenesis. Alkaline phosphatase was also detected in the nuclear membrane and nuclear matrix, suggesting an association with the nucleo-cytoplasmic transport of ribonucleoproteins and the mechanisms of cell cycle and DNA replication, respectively. This study highlights the importance of alkaline phosphatase in the salivary gland of R. prolixus and R. neglectus and emphasizes its importance in secretory activity. Secretory activity is directly involved in hematophagy and, consequently, in development during metamorphosis. The observed presence of alkaline phosphatase suggests its involvement in the production of saliva allowing feeding of these insects that are important vectors of Chagas disease.

  16. Synthesis and phosphatase activity of a Cobalt(II) phenanthroline ...

    Indian Academy of Sciences (India)

    MAMONI GARAI

    2017-09-19

    Sep 19, 2017 ... The cobalt(II) complex has been evaluated as a functional model for phosphatase enzyme by using 4-nitrophenylphosphate. (PNPP) as a standard substrate in aqueous DMF medium. ... Designed coordination molecules with an ability to mimic the ... tion, cobalt complexes have gained importance because.

  17. Activation of Rat Intestinal Alkaline Phosphatase by Taurine May be ...

    African Journals Online (AJOL)

    Dr. K.J. Umar

    targets for the gut mucosal defense factor intestinal alkaline phosphatase. American Journal of. Physiology-Gastrointestinal and Liver Physiology,. 299(2): G467–G475. Corrigan, J.J., Ray, W.L and May, N. (1968). Changes in the blood coagulation system associated with septicemia. The New England Journal of Medicine,.

  18. Lipid accumulation and alkaline phosphatase activity in human ...

    African Journals Online (AJOL)

    Background: Alkaline phosphatase (ALP) controls intracellular lipid accumulation in human preadipocytes, but it is not known whether ALP is expressed in all body fat depots, or whether it has a similar role at all sites. Design: Cross-sectional. Setting and subjects: Subjects undergoing breast reduction and abdominal fat ...

  19. In vitro production of growth regulators and phosphatase activity by ...

    African Journals Online (AJOL)

    The result showed that the population levels of phosphobacteria were higher in the rhizosphere soil of groundnut plant. Further, all the strains of phosphobacteria were able to produce phytohormones and phosphatase enzyme under in vitro conditions. Keywords: In vitro, phosphobacteria, growth regulators ...

  20. Lipid accumulation and alkaline phosphatase activity in human ...

    African Journals Online (AJOL)

    2012-10-03

    Oct 3, 2012 ... Background: Alkaline phosphatase (ALP) controls intracellular lipid accumulation in human preadipocytes, but it is not known whether ALP .... glutamine, supplemented with 10% foetal bovine serum and 100 U/ml penicillin ..... by a cascade of transcription factor gene expression.34. Evidence that ALP acts ...

  1. Protein phosphatases decrease their activity during capacitation: a new requirement for this event.

    Directory of Open Access Journals (Sweden)

    Janetti R Signorelli

    Full Text Available There are few reports on the role of protein phosphatases during capacitation. Here, we report on the role of PP2B, PP1, and PP2A during human sperm capacitation. Motile sperm were resuspended in non-capacitating medium (NCM, Tyrode's medium, albumin- and bicarbonate-free or in reconstituted medium (RCM, NCM plus 2.6% albumin/25 mM bicarbonate. The presence of the phosphatases was evaluated by western blotting and the subcellular localization by indirect immunofluorescence. The function of these phosphatases was analyzed by incubating the sperm with specific inhibitors: okadaic acid, I2, endothall, and deltamethrin. Different aliquots were incubated in the following media: 1 NCM; 2 NCM plus inhibitors; 3 RCM; and 4 RCM plus inhibitors. The percent capacitated sperm and phosphatase activities were evaluated using the chlortetracycline assay and a phosphatase assay kit, respectively. The results confirm the presence of PP2B and PP1 in human sperm. We also report the presence of PP2A, specifically, the catalytic subunit and the regulatory subunits PR65 and B. PP2B and PP2A were present in the tail, neck, and postacrosomal region, and PP1 was present in the postacrosomal region, neck, middle, and principal piece of human sperm. Treatment with phosphatase inhibitors rapidly (≤1 min increased the percent of sperm depicting the pattern B, reaching a maximum of ∼40% that was maintained throughout incubation; after 3 h, the percent of capacitated sperm was similar to that of the control. The enzymatic activity of the phosphatases decreased during capacitation without changes in their expression. The pattern of phosphorylation on threonine residues showed a sharp increase upon treatment with the inhibitors. In conclusion, human sperm express PP1, PP2B, and PP2A, and the activity of these phosphatases decreases during capacitation. This decline in phosphatase activities and the subsequent increase in threonine phosphorylation may be an important

  2. TORC1 regulates Pah1 phosphatidate phosphatase activity via the Nem1/Spo7 protein phosphatase complex.

    Directory of Open Access Journals (Sweden)

    Emmanuelle Dubots

    Full Text Available The evolutionarily conserved target of rapamycin complex 1 (TORC1 controls growth-related processes such as protein, nucleotide, and lipid metabolism in response to growth hormones, energy/ATP levels, and amino acids. Its deregulation is associated with cancer, type 2 diabetes, and obesity. Among other substrates, mammalian TORC1 directly phosphorylates and inhibits the phosphatidate phosphatase lipin-1, a central enzyme in lipid metabolism that provides diacylglycerol for the synthesis of membrane phospholipids and/or triacylglycerol as neutral lipid reserve. Here, we show that yeast TORC1 inhibits the function of the respective lipin, Pah1, to prevent the accumulation of triacylglycerol. Surprisingly, TORC1 regulates Pah1 in part indirectly by controlling the phosphorylation status of Nem1 within the Pah1-activating, heterodimeric Nem1-Spo7 protein phosphatase module. Our results delineate a hitherto unknown TORC1 effector branch that controls lipin function in yeast, which, given the recent discovery of Nem1-Spo7 orthologous proteins in humans, may be conserved.

  3. Phosphorus resorption by young beech trees and soil phosphatase activity as dependent on phosphorus availability.

    Science.gov (United States)

    Hofmann, Kerstin; Heuck, Christine; Spohn, Marie

    2016-06-01

    Motivated by decreasing foliar phosphorus (P) concentrations in Fagus sylvatica L. forests, we studied P recycling depending on P fertilization in mesocosms with juvenile trees and soils of two contrasting F. sylvatica L. forests in a greenhouse. We hypothesized that forests with low soil P availability are better adapted to recycle P than forests with high soil P availability. The P resorption efficiency from senesced leaves was significantly higher at the P-poor site (70 %) than at the P-rich site (48 %). P fertilization decreased the resorption efficiency significantly at the P-poor site to 41 %, while it had no effect at the P-rich site. Both acid and alkaline phosphatase activity were higher in the rhizosphere of the P-poor than of the P-rich site by 53 and 27 %, respectively, while the activities did not differ in the bulk soil. Fertilization decreased acid phosphatase activity significantly at the P-poor site in the rhizosphere, but had no effect on the alkaline, i.e., microbial, phosphatase activity at any site. Acid phosphatase activity in the P-poor soil was highest in the rhizosphere, while in the P-rich soil, it was highest in the bulk soil. We conclude that F. sylvatica resorbed P more efficiently from senescent leaves at low soil P availability than at high P availability and that acid phosphatase activity in the rhizosphere but not in the bulk soil was increased at low P availability. Moreover, we conclude that in the P-rich soil, microbial phosphatases contributed more strongly to total phosphatase activity than plant phosphatases.

  4. Influence of acid phosphatase activity on the saccharification of potato maltodextrins by Aspergillus niger glucoamylase

    Energy Technology Data Exchange (ETDEWEB)

    Zyla, K. (Akademia Rolnicza, Cracow (Poland). Dept. of Biotechnology)

    1990-01-01

    A preparation of Aspergillus niger acid phosphatase, which had the temperature optimum 60deg C, pH optimum 1.8-3.0; good stability at pH 4-5, the ability to hydrolyze glucose-6-phosphate at a high rate, and substantial lack of glucogenic activities, was used simultaneously with a glucoamylase in order to learn its influence on the saccharification of potato maltodextrins. The addition of the acid phosphatase activity in amounts that gave the 50 fold increase, as compared to phosphatase activity which naturally occurs in the gluocoamylase (GA) preparation 'AMG-200', was found to influence on the DE level, mainly at the high substrate concentration (40% d.s.) and low glucoamylase dosage (60-100 GAU/kg d.s.). It may also be possible, when using the acid phosphatase addition, to shorten the saccharification time. (orig.).

  5. A study of the alkaline and acid phosphatase activities in acute uranium intoxication

    International Nuclear Information System (INIS)

    Bokova, N.; Pavlova, V.; Stancheva, Yu.; Khadzhirusev, S.; Kiradzhiev, G.

    1975-01-01

    Comparative study of the ability of the sodium salt of diethylbarbituric acid and acetazolamide to protect the kidneys is conducted under conditions of acute uranium intoxication in rats. The parameters studied are alkaline and acid phosphatase activities in the serum and urine and phosphatase activity in the kidneys (histochemically as described by Gomori) followed up until the 30th day after the total uranyl acetate dose was reached (2 or 7 mg per kg bodyweight). Either compound exerted only minor effect on serum alkaline phosphatase activity. Sodium diethylbarbiturate induced distinct fluctuations in urinary alkaline phosphatase activity throughout the entire study period, but the differences never reached statistical significance. Acetazolamide caused essential decrease in urinary alkaline phosphatase activity. In either case renal tissue protection from the action of the uranyl ion may be suggested. This assumption is supported by the histochemical analysis. The compounds appeared to have no effect on serum acid phosphatase activity which showed high variability both in control and in treated rats. (Ch.K.)

  6. Induction of acid phosphatase activity during germination of maize (Zea mays) seeds.

    Science.gov (United States)

    Senna, R; Simonin, V; Silva-Neto, M A C; Fialho, E

    2006-01-01

    Acid phosphatase activity (orthophosphoric-monoester phosphohydrolase, EC 3.1.3.2) increased during the first 24 h of maize (Zea mays) seed germination. The enzyme displayed a pH optimum of 4.5-5.5. Catalytic activity in vitro displayed a linear time course (60 min) and reached its half maximum value at 0.47 mM p-nitrophenyl phosphate (pNPP). Phosphatase activity towards phosphoamino acids was greatest for phosphotyrosine. The phosphatase activity was strongly inhibited by ammonium molybdate, vanadate and NaF and did not require divalent cations for the catalysis. The temperature optimum for pNPP hydrolysis was 37 degrees C. Under the same conditions, no enzyme activity was detected with phytic acid as substrate. Western blotting of total homogenates during seed germination revealed proteins/polypeptides that were phosphorylated on tyrosine residues; a protein of approximately 14 kDa is potentially a major biological substrate for the phosphatase activity. The results presented in this study suggest that the acid phosphatase characterized under the tested conditions is a member of the phosphotyrosine phosphatase family.

  7. FAS activation induces dephosphorylation of SR proteins - Dependence on the de novo generation of ceramide and activation of protein phosphatase 1

    NARCIS (Netherlands)

    Chalfant, CE; Ogretmen, B; Galadari, S; Kroesen, BJ; Pettus, BJ; Hannun, YA

    2001-01-01

    The search for potential targets for ceramide action led to the identification of ceramide-activated protein phosphatases (CAPP). To date, two serine/threonine protein phosphatases, protein phosphatase 2A (PP2A) and protein phosphatase 1 (PP1), have been demonstrated to function as

  8. Phosphatase activity of staphylococci is constitutive in some species and repressed by phosphates in others.

    OpenAIRE

    Soro, O; Grazi, G; Varaldo, P E; Satta, G

    1990-01-01

    The phosphatase activities of colonies of staphylococcal strains belonging to the 10 species most frequently isolated from specimens of human origin were evaluated on media with undetermined inorganic phosphate contents and on media supplemented with known amounts of phosphates. All strains of all species tested were phosphatase positive on plates that were not supplemented with inorganic phosphates when the pH of the medium was high. In media supplemented with 0.3% phosphates at low and high...

  9. Promoting Uranium Immobilization by the Activities of Microbial Phosphatases

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Robert J.; Beazley, Melanie J.; Wilson, Jarad J.; Taillefert, Martial; Sobecky, Patricia A.

    2005-04-05

    The overall goal of this project is to examine the role of nonspecific phosphohydrolases present in naturally occurring subsurface microorganisms for the purpose of promoting the immobilization of radionuclides through the production of uranium [U(VI)] phosphate precipitates. Specifically, we hypothesize that the precipitation of U(VI) phosphate minerals may be promoted through the microbial release and/or accumulation of PO{sub 4}{sup 3-}. During this phase of the project we have been conducting assays to determine the effects of pH, inorganic anions and organic ligands on U(VI) mineral formation and precipitation when FRC bacterial isolates were grown in simulated groundwater medium. The molecular characterization of FRC isolates has also been undertaken during this phase of the project. Analysis of a subset of gram-positive FRC isolates cultured from FRC soils (Areas 1, 2 and 3) and background sediments have indicated a higher percentage of isolates exhibiting phosphatase phenotypes (i.e., in particular those surmised to be PO{sub 4}{sup 3-}-irrepressible) relative to isolates from the reference site. A high percentage of strains that exhibited such putatively PO{sub 4}{sup 3-}-irrepressible phosphatase phenotypes were also resistant to the heavy metals lead and cadmium. Previous work on FRC strains, including Arthrobacter, Bacillus and Rahnella spp., has demonstrated differences in tolerance to U(VI) toxicity (200 {micro}M) in the absence of organophosphate substrates. For example, Arthrobacter spp. exhibited the greatest tolerance to U(VI) while the Rahnella spp. have been shown to facilitate the precipitation of U(VI) from solution and the Bacillus spp. demonstrate the greatest sensitivity to acidic conditions and high concentrations of U(VI). PCR-based detection of FRC strains are being conducted to determine if non-specific acid phosphatases of the known molecular classes [i.e., classes A, B and C] are present in these FRC isolates. Additionally, these

  10. Differentiating intracellular from extracellular alkaline phosphatase activity in soil by sonication.

    Directory of Open Access Journals (Sweden)

    Shuping Qin

    Full Text Available Differentiating intracellular from extracellular enzyme activity is important in soil enzymology, but not easy. Here, we report on an adjusted sonication method for the separation of intracellular from extracellular phosphatase activity in soil. Under optimal sonication conditions [soil:water ratio  =  1/8 (w/v and power density  =  15 watt ml(-1], the activity of alkaline phosphomonoesterase (phosphatase in a Haplic Cambisol soil increased with sonication time in two distinct steps. A first plateau of enzyme activity was reached between 60 and 100 s, and a second higher plateau after 300 s. We also found that sonication for 100 s under optimal conditions activated most (about 80% of the alkaline phosphatase that was added to an autoclaved soil, while total bacteria number was not affected. Sonication for 300 s reduced the total bacteria number by three orders of magnitude but had no further effects on enzyme activity. Our results indicate that the first plateau of alkaline phosphatase activity was derived from extracellular enzymes attached to soil particles, and the second plateau to the combination of extracellular and intracellular enzymes after cell lysis. We conclude that our adjusted sonication method may be an alternative to the currently used physiological and chloroform-fumigation methods for differentiating intracellular from extracellular phosphatase activity in soil. Further testing is needed to find out whether this holds for other soil types.

  11. Semi-Automatic Rating Method for Neutrophil Alkaline Phosphatase Activity.

    Science.gov (United States)

    Sugano, Kanae; Hashi, Kotomi; Goto, Misaki; Nishi, Kiyotaka; Maeda, Rie; Kono, Keigo; Yamamoto, Mai; Okada, Kazunori; Kaga, Sanae; Miwa, Keiko; Mikami, Taisei; Masauzi, Nobuo

    2017-01-01

    The neutrophil alkaline phosphatase (NAP) score is a valuable test for the diagnosis of myeloproliferative neoplasms, but it has still manually rated. Therefore, we developed a semi-automatic rating method using Photoshop ® and Image-J, called NAP-PS-IJ. Neutrophil alkaline phosphatase staining was conducted with Tomonaga's method to films of peripheral blood taken from three healthy volunteers. At least 30 neutrophils with NAP scores from 0 to 5+ were observed and taken their images. From which the outer part of neutrophil was removed away with Image-J. These were binarized with two different procedures (P1 and P2) using Photoshop ® . NAP-positive area (NAP-PA) and granule (NAP-PGC) were measured and counted with Image-J. The NAP-PA in images binarized with P1 significantly (P < 0.05) differed between images with NAP scores from 0 to 3+ (group 1) and those from 4+ to 5+ (group 2). The original images in group 1 were binarized with P2. NAP-PGC of them significantly (P < 0.05) differed among all four NAP score groups. The mean NAP-PGC with NAP-PS-IJ indicated a good correlation (r = 0.92, P < 0.001) to results by human examiners. The sensitivity and specificity of NAP-PS-IJ were 60% and 92%, which might be considered as a prototypic method for the full-automatic rating NAP score. © 2016 Wiley Periodicals, Inc.

  12. Protein kinase and phosphatase activities of thylakoid membranes

    International Nuclear Information System (INIS)

    Michel, H.; Shaw, E.K.; Bennett, J.

    1987-01-01

    Dephosphorylation of the 25 and 27 kDa light-harvesting Chl a/b proteins (LHCII) of the thylakoid membranes is catalyzed by a phosphatase which differs from previously reported thylakoid-bound phosphatases in having an alkaline pH optimum (9.0) and a requirement for Mg 2+ ions. Dephosphorylation of the 8.3 kDa psb H gene product requires a Mg 2+ ion concentration more than 200 fold higher than that for dephosphorylation of LHC II. The 8.3 kDa and 27 kDa proteins appear to be phosphorylated by two distinct kinases, which differ in substrate specificity and sensitivity to inhibitors. The plastoquinone antagonist 2,5-dibromo-3-methyl-6-isopropyl-benzoquinone (DBMIB) inhibits phosphorylation of the 27 kDa LHC II much more readily than phosphorylation of the 8.3 kDa protein. A similar pattern of inhibition is seen for two synthetic oligopeptides (MRKSATTKKAVC and ATQTLESSSRC) which are analogs of the phosphorylation sites of the two proteins. Possible modes of action of DBMIB are discussed. 45 refs., 7 figs., 3 tabs

  13. Phosphatase Activity of Microbial Populations in Different Milk Samples in Relation to Protein and Carbohydrate Content

    Directory of Open Access Journals (Sweden)

    Sosanka Protim SANDILYA

    2014-12-01

    Full Text Available Cattle milk is a rich source of protein, carbohydrate, vitamins, minerals and all other major and micro nutrients. At a moderate pH, milk is an excellent media for the growth of microbes and thus, intake of raw milk is precarious. In this study, attempt was made for a qualitative study of eight raw milk samples of different varieties of cow and goat milk, collected from Jorhat district of Assam, India, on the basis of nutritional value and microbial population. The highest microbial population was found in the milk collected from cross hybrid variety of cow, whereas microbial contamination was the least in Jersey cow milk. Samples of C1 (Jersey cow variety showed presence of the highest amount of protein and carbohydrate content as compared to the others. Almost all the milk samples showed positive acid and alkaline phosphatase activity. Maximum acid phosphatase activity was observed in cross hybrid cow milk, whereas local cow milk exhibited the highest alkaline phosphatase activity. Phosphatase activity did not show any co-relationship with microbial population of the milk samples. Similarly, the protein and carbohydrate content of the samples did not have any significant impact on both acid and alkaline phosphatase activity.

  14. Phosphatase active antigens in sea urchin eggs and embryos. II. A comparison between the activities in unfertilized eggs and plutei.

    Science.gov (United States)

    Westin, M

    1975-06-01

    Phosphatase activities in sea urchin eggs and plutei were investigated by means of histochemical staining of immunoprecipitates. Two protein fractions were obtained by extraction in a hypotonic medium and by detergent treatment of the residual pellet. Three distinctly different phosphatase activities were discerned, nucleoside diphosphatase (EC 3.6.1.6.), acid phosphatase (EC 3.1.3.2.) and alkaline phosphatase (EC 3.1.3.1.). The nucleoside diphosphatase activity, which was confined to one antigen, was present in both water soluble and detergent extracts and at roughly the same concentration in eggs and plutei. By means of a monospecific antiserum the immunological identify of this antigen was established in all instances. The acid phosphatase activity, which was displayed by ten detergent extracted antigens in eggs, was only found in five detergent extracted antigens in plutei. This decrease in number of enzyme active antigens was also reflected by a general decrease in number of enzyme active antigens was also reflected by a general decrease in activity as assessed by quantitative determinations. Furthermore, by means of absorbed antisera it was established that two or three of the acid phosphatase active antigens were "egg specific". Another acid phosphatase active antigen, which was common to both developmental stages, was investigated by a monospecific antiserum. While this antigen was found in both soluble fractions, it was only enzymatically active when extracted with detergent. Alkaline phosphatase active antigens were only found in the detergent extract of plutei. However, immunoprecipitates with this activity appeared both with antiserum against unfertilized eggs and with antiserum against plutei. This suggests that the egg contained the antigens in an enzymatically inactive form.

  15. From phosphatases to vanadium peroxidases: a similar architecture of the active site

    NARCIS (Netherlands)

    Hemrika, W.; Renirie, R.; Dekker, H. L.; Barnett, P.; Wever, R.

    1997-01-01

    We show here that the amino acid residues contributing to the active sites of the vanadate containing haloperoxidases are conserved within three families of acid phosphatases; this suggests that the active sites of these enzymes are very similar. This is confirmed by activity measurements showing

  16. [The influence of immobilisation on the alcaline phosphatase activity from adults and children (author's transl)].

    Science.gov (United States)

    Schmitt, O

    1976-06-18

    Alcaline phosphatase activities in the sera from 75 children of the age of 2-9 years were determined after immobilisation of various degree. A significant decrease of enzymatic activity was to be seen with increasing immobilisation, in contrast to the adult, where the immobilisation had no influence on the alcaline serumphosphatase.

  17. Evidence of active NADP(+) phosphatase in dormant seeds of Avena sativa L.

    Science.gov (United States)

    Gallais, S; de Crescenzo, M A; Laval-Martin, D L

    2000-08-01

    Freshly-harvested seeds of Avena sativa L. do not germinate when imbibed at temperatures higher than 25 degrees C. This high temperature dormancy is due to the seed coats, and to the low activities of glycolysis and the oxidative pentose phosphate pathway (OPP) in the embryo. The analysis by exclusion chromatography of soluble NADP(+) phosphatase activities of embryos revealed two isoforms: a 37 kDa isoform present in both dormant and after-ripened caryopses, and a second isoform, with an apparent molecular weight of 160 kDa, five times more active in embryos of dormant seeds than in the after-ripened ones, after 6 h of imbibition at 30 degrees C. Moreover, the activity of this 160 kDa isoform was three times less in embryos from dormant caryopses when they were grown at 10 degrees C, a permissive temperature for radicle protrusion. These results suggest a correlation between the activity of the 160 kDa NADP(+) phosphatase and the dormancy state of the caryopsis. The two isoforms differed in the pH required for optimal activity: pH 5.7 and 6.5 for the 37 kDa and the 160 kDa phosphatases, respectively. Furthermore, the 160 kDa NADP(+) phosphatase displayed a strong specificity for NADP(+), whereas the 37 kDa isoform was able to hydrolyse numerous other phosphorylated compounds.

  18. Intercropping Acacia mangium stimulates AMF colonization and soil phosphatase activity in Eucalyptus grandis

    Directory of Open Access Journals (Sweden)

    Daniel Bini

    Full Text Available ABSTRACT: Arbuscular mycorrhizal fungi (AMF are very important to plant nutrition, mostly in terms of acquisition of P and micronutrients. While Acacia mangium is closely associated with AMF throughout the whole cycle, Eucalyptus grandis presents this symbiosis primarily at the seedling stage. The aim of this study was to evaluate the dynamics of AMF in these two tree species in both pure and mixed plantations during the first 20 months after planting. We evaluated the abundance, richness and diversity of AMF spores, the rate of AMF mycorrhizal root colonization, enzymatic activity and soil and litter C, N and P. There was an increase in AMF root colonization of E. grandis when intercropped with A. mangium as well as an increase in the activity of acid and alkaline phosphatase in the presence of leguminous trees. AMF colonization and phosphatase activities were both involved in improvements in P cycling and P nutrition in soil. In addition, P cycling was favored in the intercropped plantation, which showed negative correlation with litter C/N and C/P ratios and positive correlation with soil acid phosphatase activity and soil N and P concentrations. Intercropping A. mangium and E. grandis maximized AMF root colonization of E. grandis and phosphatase activity in the soil, both of which accelerate P cycling and forest performance.

  19. Structural and biochemical analysis of atypically low dephosphorylating activity of human dual-specificity phosphatase 28.

    Directory of Open Access Journals (Sweden)

    Bonsu Ku

    Full Text Available Dual-specificity phosphatases (DUSPs constitute a subfamily of protein tyrosine phosphatases, and are intimately involved in the regulation of diverse parameters of cellular signaling and essential biological processes. DUSP28 is one of the DUSP subfamily members that is known to be implicated in the progression of hepatocellular and pancreatic cancers, and its biological functions and enzymatic characteristics are mostly unknown. Herein, we present the crystal structure of human DUSP28 determined to 2.1 Å resolution. DUSP28 adopts a typical DUSP fold, which is composed of a central β-sheet covered by α-helices on both sides and contains a well-ordered activation loop, as do other enzymatically active DUSP proteins. The catalytic pocket of DUSP28, however, appears hardly accessible to a substrate because of the presence of nonconserved bulky residues in the protein tyrosine phosphatase signature motif. Accordingly, DUSP28 showed an atypically low phosphatase activity in the biochemical assay, which was remarkably improved by mutations of two nonconserved residues in the activation loop. Overall, this work reports the structural and biochemical basis for understanding a putative oncological therapeutic target, DUSP28, and also provides a unique mechanism for the regulation of enzymatic activity in the DUSP subfamily proteins.

  20. [Serum calcium and phosphorus concentration and alkaline phosphatase activity in healthy children during growth and development].

    Science.gov (United States)

    Savić, Ljiljana; Savić, Dejan

    2008-01-01

    Many changes happen during growth and development in an organism as a result of important hormon changes, especially biohumoral ones. These changes make a problem when interpreting biochemical results in pediatric population. The most important changes are intensive calcium and phosphorus metabolic turnover in bone tissue with changes in alkaline phosphatase activity as a result of osteoblast activity. The aim of this study was to follow the serum calcium and phosphorus concentration and alkaline phosphatase activity in children 1-15 years old in different growth and development period and of different sexes and to fortify the influence of growth and development dynamics on biohumoral status in healthy male and female children. We evaluated 117 healthy children of both sexes from 1-15 years of age and divided them into three age groups: 1-5, 6-10 and 11-15 years. We followed the serum calcium and phosphorus concentration and alkaline phosphatase activity in different groups and in different sexes. Our investigation found significantly higher values of serum calcium in boys than in girls with no important changes between the age groups and significantly higher values of serum phosphorus in the youngest age group in all children and in different sexes with no important sex differences. Alkaline phosphatase activity followed the growth spurt and was the biggest in 6-10 years group in girls and in 11-15 years group in boys.

  1. Alkaline phosphatase labeled SERS active sandwich immunoassay for detection of Escherichia coli

    Science.gov (United States)

    Bozkurt, Akif Goktug; Buyukgoz, Guluzar Gorkem; Soforoglu, Mehmet; Tamer, Ugur; Suludere, Zekiye; Boyaci, Ismail Hakki

    2018-04-01

    In this study, a sandwich immunoassay method utilizing enzymatic activity of alkaline phosphatase (ALP) on 5-bromo-4-chloro-3-indolyl phosphate (BCIP) for Escherichia coli (E. coli) detection was developed using surface enhanced Raman spectroscopy (SERS). For this purpose, spherical magnetic gold coated core-shell nanoparticles (MNPs-Au) and rod shape gold nanoparticles (Au-NRs) were synthesized and modified for immunomagnetic separation (IMS) of E. coli from the solution. In order to specify the developed method to ALP activity, Au-NRs were labeled with this enzyme. After successful construction of the immunoassay, BCIP substrate was added to produce the SERS-active product; 5-bromo-4-chloro-3-indole (BCI). A good linearity (R2 = 0.992) was established between the specific SERS intensity of BCI at 600 cm- 1 and logarithmic E. coli concentration in the range of 1.7 × 101-1.7 × 106 cfu mL- 1. LOD and LOQ values were also calculated and found to be 10 cfu mL- 1 and 30 cfu mL- 1, respectively.

  2. Redox Modulation of PTEN Phosphatase Activity by Hydrogen Peroxide and Bisperoxidovanadium Complexes

    NARCIS (Netherlands)

    Lee, Chang-Uk; Hahne, Gernot; Hanske, Jonas; Bange, Tanja; Bier, David; Rademacher, Christoph; Hennig, Sven; Grossmann, Tom N

    2015-01-01

    PTEN is a dual-specificity protein tyrosine phosphatase. As one of the central tumor suppressors, a thorough regulation of its activity is essential for proper cellular homeostasis. The precise implications of PTEN inhibition by reactive oxygen species (e.g. H2 O2 ) and the subsequent structural

  3. Quantification of the histochemical reaction for alkaline phosphatase activity using the indoxyl-tetranitro BT method

    NARCIS (Netherlands)

    van Noorden, C. J.; Jonges, G. N.

    1987-01-01

    The indoxyl-tetranitro BT method for the demonstration of alkaline phosphatase activity has been optimized and its validity for quantitative histochemistry tested. The study has been performed with model films of polyacrylamide gel incorporating homogenate of rat liver and with cryostat sections

  4. Effects of Alkaline Phosphatase Activity on Nucleotide Measurements in Aquatic Microbial Communities †

    OpenAIRE

    Karl, D. M.; Craven, D. B.

    1980-01-01

    Alkaline phosphatase (APase) activity was detected in aquatic microbial assemblages from the subtropics to Antarctica. The occurrence of APase in environmental nucleotide extracts was shown to significantly affect the measured concentrations of cellular nucleotides (adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, guanosine triphosphate, uridine triphosphate, and cytidine triphosphate), adenylate energy charge, and guanosine triphosphate/adenosine triphosphate ratios, w...

  5. The effects of drought stress on the activity of acid phosphatase and ...

    African Journals Online (AJOL)

    A model of drought was created on pigweed and the effects of drought stress on the activity of acid phosphatase and its protective enzymes were examined. The pot-cultured pigweeds were divided into 4 groups (ten plants per group) when they reached 6 leaves. (1) In the control group, the culture media contained 70 ...

  6. Phosphatase activity in sandy soil influenced by mycorrhizal and non-mycorrhizal cover crops

    Directory of Open Access Journals (Sweden)

    Alceu Kunze

    2011-06-01

    Full Text Available Cover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat (Avena strigosa Schreb or the non-mycorrhizal species oilseed radish (Raphanus sativus L. var. oleiferus Metzg and corn spurry (Spergula arvensis L.. The control treatment consisted of resident vegetation (fallow in the winter season. In the summer, a mixture of pearl millet (Pennisetum americanum L. with sunnhemp (Crotalaria juncea L. or with soybean (Glycine max L. was sown in all plots. Soil cores (0-10 cm and root samples were collected in six growing seasons (winter and summer of each year. Microbial biomass P was determined by the fumigation-extraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35 % higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme profile continued in the subsequent periods, during the growth of mycorrhizal summer crops, after completion of the life cycle of the cover crops.

  7. Cold-active alkaline phosphatase is irreversibly transformed into an inactive dimer by low urea concentrations.

    Science.gov (United States)

    Hjörleifsson, Jens Guðmundur; Ásgeirsson, Bjarni

    2016-07-01

    Alkaline phosphatase is a homodimeric metallo-hydrolase where both Zn(2+) and Mg(2+) are important for catalysis and stability. Cold-adapted alkaline phosphatase variants have high activity at low temperatures and lower thermal stability compared with variants from mesophilic hosts. The instability, and thus inactivation, could be due to loose association of the dimers and/or loosely bound Mg(2)(+) in the active site, but this has not been studied in detail for the cold-adapted variants. Here, we focus on using the intrinsic fluorescence of Trp in alkaline phosphatase from the marine bacterium Vibrio splendidus (VAP) to probe for dimerization. Trp→Phe substitutions showed that two out of the five native Trp residues contributed mostly to the fluorescence emission. One residue, 15Å away from the active site (W460) and highly solvent excluded, was phosphorescent and had a distant role in substrate binding. An additional Trp residue was introduced to the dimer interface to act as a possible probe for dimerization. Urea denaturation curves indicated that an inactive dimer intermediate, structurally equivalent to the native state, was formed before dimer dissociation took place. This is the first example of the transition of a native dimer to an inactive dimer intermediate for alkaline phosphatase without using mutagenesis, ligands, or competitive inhibition. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Advances in lanthanide-based luminescent peptide probes for monitoring the activity of kinase and phosphatase.

    Science.gov (United States)

    Pazos, Elena; Vázquez, M Eugenio

    2014-02-01

    Signaling pathways based on protein phosphorylation and dephosphorylation play critical roles in the orchestration of complex biochemical events and form the core of most signaling pathways in cells (i.e. cell cycle regulation, cell motility, apoptosis, etc.). The understanding of these complex signaling networks is based largely on the biochemical study of their components, i.e. kinases and phosphatases. The development of luminescent sensors for monitoring kinase and phosphatase activity is therefore an active field of research. Examples in the literature usually rely on the modulation of the fluorescence emission of organic fluorophores. However, given the exceptional photophysical properties of lanthanide ions, there is an increased interest in their application as emissive species for monitoring kinase and phosphatase activity. This review summarizes the advances in the development of lanthanide-based luminescent peptide sensors as tools for the study of kinases and phosphatases and provides a critical description of current examples and synthetic approaches to understand these lanthanide-based luminescent peptide sensors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Free Fatty Acids Inhibit Protein Tyrosine Phosphatase 1B and Activate Akt

    Directory of Open Access Journals (Sweden)

    Eisuke Shibata

    2013-09-01

    Full Text Available Background/Aims: Accumulating evidence has suggested that free fatty acids (FFAs interact with protein kinases and protein phosphatases. The present study examined the effect of FFAs on protein phosphatases and Akt. Methods: Activities of protein phosphatase 1 (PP1, protein phosphatase 2A (PP2A, and protein tyrosine phosphatase 1B (PTP1B were assayed under the cell-free conditions. Phosphorylation of Akt was monitored in MSTO-211H human malignant pleural mesothelioma cells without and with knocking-down phosphatidylinositol 3 kinase (PI3K or 3-phosphoinositide-dependent protein kinase-1 (PDK1. Results: In the cell-free assay, unsaturated FFAs (uFFAs such as oleic, linoleic and linolenic acid and saturated FFAs (sFFAs such as stearic, palmitic, myristic, and behenic acid markedly reduced PTP1B activity, with the potential for uFFAs greater than that for sFFAs. All the investigated sFFAs inhibited PP2A activity, but otherwise no inhibition was obtained with uFFAs. Both uFFAs and sFFAs had no effect on PP1 activity. Oleic acid phosphorylated Akt both on Thr308 and Ser473, while stearic acid phosphorylated Akt on Thr308 alone. The effects of oleic and stearic acid on Akt phosphorylation were abrogated by the PI3K inhibitor wortmannin or the PDK1 inhibitor BX912 and also by knocking-down PI3K or PDK1. Conclusion: The results of the present study indicate that uFFAs and sFFAs could activate Akt through a pathway along a PI3K/PDK1/Akt axis in association with PTP1B inhibition.

  10. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Science.gov (United States)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  11. Somatic cell count and alkaline phosphatase activity in milk for evaluation of mastitis in buffalo

    Directory of Open Access Journals (Sweden)

    M. P. Patil

    2015-03-01

    Full Text Available Background and Aim: Mastitis is a serious disease of dairy animals causing great economic losses due to a reduction in milk yield as well as lowering its nutritive value. The application of somatic cell count (SCC and alkaline phosphatase activity in the milk for diagnosis of mastitis in buffalo is not well documented. Therefore, the present study was conducted to observe the SCC and alkaline phosphatase activity for evaluation of mastitis in buffalo. Materials and Methods: Milk samples of forty apparently healthy lactating buffaloes were selected and categorized into five different groups viz. normal buffaloes, buffaloes with subclinical mastitis with CMT positive milk samples (+1 Grade, (+2 Grade, (+3 Grade, and buffaloes with clinical mastitis with 8 animals in each group. The milk samples were analyzed for SCC and alkaline phosphatase activity. Results: The levels of SCC (×105 cells/ml and alkaline phosphatase (U/L in different groups were viz. normal (3.21±0.179, 16.48±1.432, subclinical mastitis with CMT positive milk samples with +1 Grade (4.21±0.138, 28.11±1.013, with +2 Grade (6.34±0.183, 34.50±1.034, with +3 Grade (7.96±0.213, 37.73±0.737 and buffaloes with clinical mastitis (10.21±0.220, 42.37±0.907 respectively, indicating an increasing trend in the values and the difference observed among various group was statistically significant. Conclusion: In conclusion, the results of the present study indicate that the concentration of milk SCC and alkaline phosphatase activity was higher in the milk of buffaloes with mastitis than in the milk of normal buffaloes.

  12. Somatic cell count and alkaline phosphatase activity in milk for evaluation of mastitis in buffalo

    Science.gov (United States)

    Patil, M. P.; Nagvekar, A. S.; Ingole, S. D.; Bharucha, S. V.; Palve, V. T.

    2015-01-01

    Background and Aim: Mastitis is a serious disease of dairy animals causing great economic losses due to a reduction in milk yield as well as lowering its nutritive value. The application of somatic cell count (SCC) and alkaline phosphatase activity in the milk for diagnosis of mastitis in buffalo is not well documented. Therefore, the present study was conducted to observe the SCC and alkaline phosphatase activity for evaluation of mastitis in buffalo. Materials and Methods: Milk samples of forty apparently healthy lactating buffaloes were selected and categorized into five different groups viz. normal buffaloes, buffaloes with subclinical mastitis with CMT positive milk samples (+1 Grade), (+2 Grade), (+3 Grade), and buffaloes with clinical mastitis with 8 animals in each group. The milk samples were analyzed for SCC and alkaline phosphatase activity. Results: The levels of SCC (×105 cells/ml) and alkaline phosphatase (U/L) in different groups were viz. normal (3.21±0.179, 16.48±1.432), subclinical mastitis with CMT positive milk samples with +1 Grade (4.21±0.138, 28.11±1.013), with +2 Grade (6.34±0.183, 34.50±1.034), with +3 Grade (7.96±0.213, 37.73±0.737) and buffaloes with clinical mastitis (10.21±0.220, 42.37±0.907) respectively, indicating an increasing trend in the values and the difference observed among various group was statistically significant. Conclusion: In conclusion, the results of the present study indicate that the concentration of milk SCC and alkaline phosphatase activity was higher in the milk of buffaloes with mastitis than in the milk of normal buffaloes. PMID:27047098

  13. 24-h monitoring of calcineurin phosphatase activity in healthy subjects

    DEFF Research Database (Denmark)

    Koefoed-Nielsen, P.B.; Karamperis, N.; Jørgensen, Kaj Anker

    2005-01-01

    remain to be described. The aim of this study was to investigate whether CaN displays circadian variation or sex difference is present in healthy subjects. Twenty subjects had blood samples drawn every 4 h for a 24-h period. CaN activity was determined in whole blood as the release of 32P from...... a phosphorylated peptide. Activity of the 32P was quantitated by liquid scintillation and results converted to units CaN utilizing a calibration curve. We found no circadian variation in CaN activity and no difference between the two sexes. The clinical importance of these findings is that blood samples...... for calcineurin activity can be drawn without taking the exact time of day into consideration, but only considering the time of drug intake Udgivelsesdato: 2005/9...

  14. Haemoglobin and Lung Total and Lysosomal Phosphatase Activity ...

    African Journals Online (AJOL)

    Smoking of ordinary cigarette exposes its active smokers to health hazards and the filter-tipped cigarette, is said to reduce the hazards. However, it is not certain if the filter-tipped cigarette reduces the hazards in passive smokers since they inhail the cigarette smoke through their nostrils regardless of whether the cigarette is ...

  15. Protein phosphatase 1α is a Ras-activated Bad phosphatase that regulates interleukin-2 deprivation-induced apoptosis

    OpenAIRE

    Ayllón, Verónica; Martínez-A, Carlos; García, Alphonse; Cayla, Xavier; Rebollo, Angelita

    2000-01-01

    Growth factor deprivation is a physiological mechanism to regulate cell death. We utilize an interleukin-2 (IL-2)-dependent murine T-cell line to identify proteins that interact with Bad upon IL-2 stimulation or deprivation. Using the yeast two-hybrid system, glutathione S-transferase (GST) fusion proteins and co-immunoprecipitation techniques, we found that Bad interacts with protein phosphatase 1α (PP1α). Serine phosphorylation of Bad is induced by IL-2 and its dephosphorylation correlates ...

  16. Effect of Hypodynamy on Structure and Alkaline Phosphatase Activity of Kidney in Japanese Quails

    Directory of Open Access Journals (Sweden)

    V. Almášiová

    2008-01-01

    Full Text Available The objective of the study was to observe the effect of experimental hypodynamy simulating weightlessness in space on the structure, ultrastructure and alkaline phosphatase activity of kidney in Japanese quail (Coturnix coturnix japonica. Two days after hatching, the quails were suspended in special shirts below the cage ceiling so their feet did not touch the floor. They could consume food and water ad libitum. Experimental animals were sacrificed after 14, 21, 28, 35, 42, 49 and 56 days of hypodynamy. Birds of the same age, hatched at the same time, and fed the same diet were used as a control. Samples of kidney were processed for light (LM and transmission electron microscopy (TEM, and alkaline phosphatase (AP analysis. Short-term (14–28 days hypodynamy caused no marked damage to the structure and ultrastructure of kidneys. However, after long-term (35–59 days hypodynamy, morphological changes were observed in some cells of the proximal and distal tubules. The dying cells in proximal tubules, observed in semi-thin sections by LM, were dark and contained a nucleus of irregular shape. Observation by TEM showed that their nucleus was dark and shrivelled and the electron-dense cytoplasm contained long, dense, rod-shaped mitochondria with thin mitochondrial cristae. Microvilli were present on the apical surface of cells and formed a brush border. Sporadic dying cells were also observed in distal tubules. Large, light vacuoles were found in the cytoplasm of cells of collecting tubules, however, the structure of renal corpuscles and medullary loops remained undisturbed. Microscopical analysis by means of a direct TUNEL reaction on days 35 to 59 of hypodynamy showed a moderate occurrence of cellular apoptosis in the proximal and distal tubules of experimental Japanese quail. The activity of AP in the brush border of the proximal tubules on days 14–29 of hypodynamy was normal in experimental animals and showed no significant differences in

  17. A novel class of PTEN protein in Arabidopsis displays unusual phosphoinositide phosphatase activity and efficiently binds phosphatidic acid

    NARCIS (Netherlands)

    Pribat, A.; Sormani, R.; Rousseau-Gueutin, M.; Julkowska, M.M.; Testerink, C.; Joubès, J.; Castroviejo, M.; Laguerre, M.; Meyer, C.; Germain, V.; Rothan, C.

    2012-01-01

    PTEN proteins are dual phosphatases with both protein and phosphoinositide phosphatase activity. They modulate signaling pathways controlling growth, metabolism and apoptosis in animals and are implied in several human diseases. We describe here a novel class of PTEN proteins in plants, termed

  18. Identification of protein phosphatase involvement in the AT-receptor induced activation of endothelial nitric oxide synthase

    DEFF Research Database (Denmark)

    Peluso, A Augusto; Bertelsen, Jesper Bork; Andersen, Kenneth

    2018-01-01

    -antagonist), L-NAME (10µM; eNOS inhibitor), MK-2206 (100nM; Akt-inhibitor) sodium fluoride (1nM; serine/threonine-phosphatase inhibitor) or sodium orthovanadate (10nM; tyrosine-phosphatase inhibitor). NO release was estimated by quantifying DAF-FM fluorescence. The phosphorylation status of activating (e...

  19. A Nucleotide Phosphatase Activity in the Nucleotide Binding Domain of an Orphan Resistance Protein from Rice*

    Science.gov (United States)

    Fenyk, Stepan; de San Eustaquio Campillo, Alba; Pohl, Ehmke; Hussey, Patrick J.; Cann, Martin J.

    2012-01-01

    Plant resistance proteins (R-proteins) are key components of the plant immune system activated in response to a plethora of different pathogens. R-proteins are P-loop NTPase superfamily members, and current models describe their main function as ATPases in defense signaling pathways. Here we show that a subset of R-proteins have evolved a new function to combat pathogen infection. This subset of R-proteins possesses a nucleotide phosphatase activity in the nucleotide-binding domain. Related R-proteins that fall in the same phylogenetic clade all show the same nucleotide phosphatase activity indicating a conserved function within at least a subset of R-proteins. R-protein nucleotide phosphatases catalyze the production of nucleoside from nucleotide with the nucleotide monophosphate as the preferred substrate. Mutation of conserved catalytic residues substantially reduced activity consistent with the biochemistry of P-loop NTPases. Kinetic analysis, analytical gel filtration, and chemical cross-linking demonstrated that the nucleotide-binding domain was active as a multimer. Nuclear magnetic resonance and nucleotide analogues identified the terminal phosphate bond as the target of a reaction that utilized a metal-mediated nucleophilic attack by water on the phosphoester. In conclusion, we have identified a group of R-proteins with a unique function. This biochemical activity appears to have co-evolved with plants in signaling pathways designed to resist pathogen attack. PMID:22157756

  20. A nucleotide phosphatase activity in the nucleotide binding domain of an orphan resistance protein from rice.

    Science.gov (United States)

    Fenyk, Stepan; Campillo, Alba de San Eustaquio; Pohl, Ehmke; Hussey, Patrick J; Cann, Martin J

    2012-02-03

    Plant resistance proteins (R-proteins) are key components of the plant immune system activated in response to a plethora of different pathogens. R-proteins are P-loop NTPase superfamily members, and current models describe their main function as ATPases in defense signaling pathways. Here we show that a subset of R-proteins have evolved a new function to combat pathogen infection. This subset of R-proteins possesses a nucleotide phosphatase activity in the nucleotide-binding domain. Related R-proteins that fall in the same phylogenetic clade all show the same nucleotide phosphatase activity indicating a conserved function within at least a subset of R-proteins. R-protein nucleotide phosphatases catalyze the production of nucleoside from nucleotide with the nucleotide monophosphate as the preferred substrate. Mutation of conserved catalytic residues substantially reduced activity consistent with the biochemistry of P-loop NTPases. Kinetic analysis, analytical gel filtration, and chemical cross-linking demonstrated that the nucleotide-binding domain was active as a multimer. Nuclear magnetic resonance and nucleotide analogues identified the terminal phosphate bond as the target of a reaction that utilized a metal-mediated nucleophilic attack by water on the phosphoester. In conclusion, we have identified a group of R-proteins with a unique function. This biochemical activity appears to have co-evolved with plants in signaling pathways designed to resist pathogen attack.

  1. Modulation of catalytic activity in multi-domain protein tyrosine phosphatases.

    Directory of Open Access Journals (Sweden)

    Lalima L Madan

    Full Text Available Signaling mechanisms involving protein tyrosine phosphatases govern several cellular and developmental processes. These enzymes are regulated by several mechanisms which include variation in the catalytic turnover rate based on redox stimuli, subcellular localization or protein-protein interactions. In the case of Receptor Protein Tyrosine Phosphatases (RPTPs containing two PTP domains, phosphatase activity is localized in their membrane-proximal (D1 domains, while the membrane-distal (D2 domain is believed to play a modulatory role. Here we report our analysis of the influence of the D2 domain on the catalytic activity and substrate specificity of the D1 domain using two Drosophila melanogaster RPTPs as a model system. Biochemical studies reveal contrasting roles for the D2 domain of Drosophila Leukocyte antigen Related (DLAR and Protein Tyrosine Phosphatase on Drosophila chromosome band 99A (PTP99A. While D2 lowers the catalytic activity of the D1 domain in DLAR, the D2 domain of PTP99A leads to an increase in the catalytic activity of its D1 domain. Substrate specificity, on the other hand, is cumulative, whereby the individual specificities of the D1 and D2 domains contribute to the substrate specificity of these two-domain enzymes. Molecular dynamics simulations on structural models of DLAR and PTP99A reveal a conformational rationale for the experimental observations. These studies reveal that concerted structural changes mediate inter-domain communication resulting in either inhibitory or activating effects of the membrane distal PTP domain on the catalytic activity of the membrane proximal PTP domain.

  2. Functional analysis of TPM domain containing Rv2345 of Mycobacterium tuberculosis identifies its phosphatase activity.

    Science.gov (United States)

    Sinha, Avni; Eniyan, Kandasamy; Sinha, Swati; Lynn, Andrew Michael; Bajpai, Urmi

    2015-07-01

    Mycobacterium tuberculosis (Mtb) is the causal agent of tuberculosis, the second largest infectious disease. With the rise of multi-drug resistant strains of M. tuberculosis, serious challenge lies ahead of us in treating the disease. The availability of complete genome sequence of Mtb has improved the scope for identifying new proteins that would not only further our understanding of biology of the organism but could also serve to discover new drug targets. In this study, Rv2345, a hypothetical membrane protein of M. tuberculosis H37Rv, which is reported to be a putative ortholog of ZipA cell division protein has been assigned function through functional annotation using bioinformatics tools followed by experimental validation. Sequence analysis showed Rv2345 to have a TPM domain at its N-terminal region and predicted it to have phosphatase activity. The TPM domain containing region of Rv2345 was cloned and expressed using pET28a vector in Escherichia coli and purified by Nickel affinity chromatography. The purified TPM domain was tested in vitro and our results confirmed it to have phosphatase activity. The enzyme activity was first checked and optimized with pNPP as substrate, followed by using ATP, which was also found to be used as substrate by the purified protein. Hence sequence analysis followed by in vitro studies characterizes TPM domain of Rv2345 to contain phosphatase activity. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Interaction between Salt-inducible Kinase 2 and Protein Phosphatase 2A Regulates the Activity of Calcium/Calmodulin-dependent Protein Kinase I and Protein Phosphatase Methylesterase-1*

    Science.gov (United States)

    Lee, Chia-Wei; Yang, Fu-Chia; Chang, Hsin-Yun; Chou, Hanyi; Tan, Bertrand Chin-Ming; Lee, Sheng-Chung

    2014-01-01

    Salt-inducible kinase 2 (SIK2) is the only AMP-activated kinase (AMPK) family member known to interact with protein phosphatase 2 (PP2A). However, the functional aspects of this complex are largely unknown. Here we report that the SIK2·PP2A complex preserves both kinase and phosphatase activities. In this capacity, SIK2 attenuates the association of the PP2A repressor, the protein phosphatase methylesterase-1 (PME-1), thus preserving the methylation status of the PP2A catalytic subunit. Furthermore, the SIK2·PP2A holoenzyme complex dephosphorylates and inactivates Ca2+/calmodulin-dependent protein kinase I (CaMKI), an upstream kinase for phosphorylating PME-1/Ser15. The functionally antagonistic SIK2·PP2A and CaMKI and PME-1 networks thus constitute a negative feedback loop that modulates the phosphatase activity of PP2A. Depletion of SIK2 led to disruption of the SIK2·PP2A complex, activation of CaMKI, and downstream effects, including phosphorylation of HDAC5/Ser259, sequestration of HDAC5 in the cytoplasm, and activation of myocyte-specific enhancer factor 2C (MEF2C)-mediated gene expression. These results suggest that the SIK2·PP2A complex functions in the regulation of MEF2C-dependent transcription. Furthermore, this study suggests that the tightly linked regulatory loop comprised of the SIK2·PP2A and CaMKI and PME-1 networks may function in fine-tuning cell proliferation and stress response. PMID:24841198

  4. Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest.

    Science.gov (United States)

    Cabugao, Kristine G; Timm, Collin M; Carrell, Alyssa A; Childs, Joanne; Lu, Tse-Yuan S; Pelletier, Dale A; Weston, David J; Norby, Richard J

    2017-01-01

    Tropical forests generally occur on highly weathered soils that, in combination with the immobility of phosphorus (P), often result in soils lacking orthophosphate, the form of P most easily metabolized by plants and microbes. In these soils, mineralization of organic P can be the major source for orthophosphate. Both plants and microbes encode for phosphatases capable of mineralizing a range of organic P compounds. However, the activity of these enzymes depends on several edaphic factors including P availability, tree species, and microbial communities. Thus, phosphatase activity in both roots and the root microbial community constitute an important role in P mineralization and P nutrient dynamics that are not well studied in tropical forests. To relate phosphatase activity of roots and bacteria in tropical forests, we measured phosphatase activity in roots and bacterial isolates as well as bacterial community composition from the rhizosphere. Three forests in the Luquillo Mountains of Puerto Rico were selected to represent a range of soil P availability as measured using the resin P method. Within each site, a minimum of three tree species were chosen to sample. Root and bacterial phosphatase activity were both measured using a colorimetric assay with para-nitrophenyl phosphate as a substrate for the phosphomonoesterase enzyme. Both root and bacterial phosphatase were chiefly influenced by tree species. Though tree species was the only significant factor in root phosphatase activity, there was a negative trend between soil P availability and phosphatase activity in linear regressions of average root phosphatase and resin P. Permutational multivariate analysis of variance of bacterial community composition based on 16S amplicon sequencing indicated that bacterial composition was strongly controlled by soil P availability ( p -value mineralization and model representation of tropical forests.

  5. Phosphatase active antigens in sea urchin eggs and embryos. I. Substrate specificity, pH-optima and inhibitors.

    Science.gov (United States)

    Westin, M

    1975-06-01

    Phosphatase activity in sea urchin embryonic antigens was investigated by histochemical staining of immunoprecipitates separated by two-dimensional (crossed) immunoelectrophoresis. Unfertilized eggs were homogenized in a hypotonic medium which solubilized cytoplasmic antigens. Antigens integrated in membranes or enclosed in particles were solubilized by detergent treatment of the residual pellet. Two different phosphatase activities were discerned in the unfertilized eggs, nucleoside diphosphatase (EC 3.6.1.6.) and acid phosphatase (EC 3.1.3.2.). Nucleoside diphosphatase activity was obtained in both the water soluble and detergent extracted protein fractions. This activity was confined to one antigen. Acid phosphatase acitivity on the other hand was almost exclusively obtained in the detergent extracted fraction and about ten distinct antigens displayed this activity. The nucleoside diphosphatase active antigen preferentially hydrolyzed purine nucleoside diphosphates and to a lesser degree triphosphates of these nucleosides. The acid phosphatase active antigens had a broader substrate specificity and hydrolyzed equally well beta-glycerophosphate and nucleotides. Both activities were essentially inactive at neutral or alkaline pH values. The activities were inhibited by p-choloromercuribenzoate and accordingly stimulated by cysteine. Tartrate and sodium fluoride, however, inhibited the acid phosphatase activity while nucleoside diphosphatase activity was either stimulated or not affected at all by these agents.

  6. Root phosphatase activity, plant growth and phosphorus accumulation of maize genotypes

    Directory of Open Access Journals (Sweden)

    Machado Cynthia Torres de Toledo

    2004-01-01

    Full Text Available The activity of the enzyme phosphatase (P-ase is a physiological characteristic related to plant efficiency in relation to P acquisition and utilization, and is genetically variable. As part of a study on maize genotype characterization in relation to phosphorus (P uptake and utilization efficiency, two experiments were set up to measure phosphatase (P-ase activity in intact roots of six local and improved maize varieties and two sub-populations. Plants were grown at one P level in nutrient solution (4 mg L-1 and the P-ase activity assay was run using 17-day-old plants for varieties and 24-day-old plants for subpopulations. Shoot and root dry matter yields and P concentrations and contents in plant parts were determined, as well as P-efficiency indexes. Root P-ase activity differed among varieties, and highest enzimatic activities were observed in two local varieties -'Catetão' and 'Caiano' -and three improved varieties -'Sol da Manhã', 'Nitrodente' and 'BR 106'. 'Carioca', a local variety, had the lowest activity. Between subpopulations, 'ND2', with low yielding and poorly P-efficient plants, presented higher root P-ase activity as compared to 'ND10', high yielding and highly P-efficient plants. In general, subpopulations presented lower P-ase activities as compared to varieties. Positive and/or negative correlations were obtained between P-ase activity and P-efficiency characteristics, specific for the genotypes, not allowing inference on a general and clear association between root-secreted phosphatase and dry matter production or P acquisition. Genotypic variability must be known and considered before using P-ase activity as an indicator of P nutritional status, or P tolerance, adaptation and efficiency under low P conditions.

  7. Dual-specificity phosphatase 3 deficiency or inhibition limits platelet activation and arterial thrombosis.

    Science.gov (United States)

    Musumeci, Lucia; Kuijpers, Marijke J; Gilio, Karen; Hego, Alexandre; Théâtre, Emilie; Maurissen, Lisbeth; Vandereyken, Maud; Diogo, Catia V; Lecut, Christelle; Guilmain, William; Bobkova, Ekaterina V; Eble, Johannes A; Dahl, Russell; Drion, Pierre; Rascon, Justin; Mostofi, Yalda; Yuan, Hongbin; Sergienko, Eduard; Chung, Thomas D Y; Thiry, Marc; Senis, Yotis; Moutschen, Michel; Mustelin, Tomas; Lancellotti, Patrizio; Heemskerk, Johan W M; Tautz, Lutz; Oury, Cécile; Rahmouni, Souad

    2015-02-17

    A limitation of current antiplatelet therapies is their inability to separate thrombotic events from bleeding occurrences. A better understanding of the molecular mechanisms leading to platelet activation is important for the development of improved therapies. Recently, protein tyrosine phosphatases have emerged as critical regulators of platelet function. This is the first report implicating the dual-specificity phosphatase 3 (DUSP3) in platelet signaling and thrombosis. This phosphatase is highly expressed in human and mouse platelets. Platelets from DUSP3-deficient mice displayed a selective impairment of aggregation and granule secretion mediated by the collagen receptor glycoprotein VI and the C-type lectin-like receptor 2. DUSP3-deficient mice were more resistant to collagen- and epinephrine-induced thromboembolism compared with wild-type mice and showed severely impaired thrombus formation on ferric chloride-induced carotid artery injury. Intriguingly, bleeding times were not altered in DUSP3-deficient mice. At the molecular level, DUSP3 deficiency impaired Syk tyrosine phosphorylation, subsequently reducing phosphorylation of phospholipase Cγ2 and calcium fluxes. To investigate DUSP3 function in human platelets, a novel small-molecule inhibitor of DUSP3 was developed. This compound specifically inhibited collagen- and C-type lectin-like receptor 2-induced human platelet aggregation, thereby phenocopying the effect of DUSP3 deficiency in murine cells. DUSP3 plays a selective and essential role in collagen- and C-type lectin-like receptor 2-mediated platelet activation and thrombus formation in vivo. Inhibition of DUSP3 may prove therapeutic for arterial thrombosis. This is the first time a protein tyrosine phosphatase, implicated in platelet signaling, has been targeted with a small-molecule drug. © 2014 American Heart Association, Inc.

  8. Phosphatase activity in relation to key litter and soil properties in mature subtropical forests in China.

    Science.gov (United States)

    Hou, Enqing; Chen, Chengrong; Wen, Dazhi; Liu, Xian

    2015-05-15

    Phosphatase-mediated phosphorus (P) mineralization is one of the critical processes in biogeochemical cycling of P and determines soil P availability in forest ecosystems; however, the regulation of soil phosphatase activity remains elusive. This study investigated the potential extracellular activities of acid phosphomonoesterase (AcPME) and phosphodiesterase (PDE) and how they were related to key edaphic properties in the L horizon (undecomposed litter) and F/H horizon (fermented and humified litter) and the underlying mineral soil at the 0-15cm depth in eight mature subtropical forests in China. AcPME activity decreased significantly in the order of F/H horizon>L horizon>mineral soil horizon, while the order for PDE activity was L horizon=F/H horizon>mineral soil horizon. AcPME (X axis) and PDE (Y axis) activities were positively correlated in all horizons with significantly higher slope in the L and F/H horizons than in the mineral soil horizon. Both AcPME and PDE activities were positively related to microbial biomass C, moisture content and water-holding capacity in the L horizon, and were positively related to soil C:P, N:P and C:N ratios and fine root (diameter≤2mm) biomass in the mineral soil horizon. Both enzyme activities were also interactively affected by forest and horizon, partly due to the interactive effect of forest and horizon on microbial biomass. Our results suggest that modulator(s) of the potential extracellular activity of phosphatases vary with horizon, depending on the relative C, P and water availability of the horizon. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. NprR, a moonlighting quorum sensor shifting from a phosphatase activity to a transcriptional activator

    Directory of Open Access Journals (Sweden)

    Stéphane Perchat

    2016-11-01

    Full Text Available Regulation of biological functions requires factors (proteins, peptides or chemicals able to sense and translate environmental conditions or any circumstances in order to modulate the transcription of a gene, the stability of a transcript or the activity of a protein. Quorum sensing is a regulation mechanism connecting cell density to the physiological state of a single cell. In bacteria, quorum sensing coordinates virulence, cell fate and commitment to sporulation and other adaptation properties. The critical role of such regulatory systems was demonstrated in pathogenicity and adaptation of bacteria from the Bacillus cereus group (i.e. B. cereus and Bacillus thuringiensis. Furthermore, using insects as a model of infection, it was shown that sequential activation of several quorum sensing systems allowed bacteria to switch from a virulence state to a necrotrophic lifestyle, allowing their survival in the host cadaver, and ultimately to the commitment into sporulation. The chronological development of these physiological states is directed by quorum sensors forming the RNPP family. Among them, NprR combines two distinct functions connecting sporulation to necrotrophism in B. thuringiensis. In the absence of its cognate signaling peptide (NprX, NprR negatively controls sporulation by acting as a phosphatase. In the presence of NprX, it acts as a transcription factor regulating a set of genes involved in the survival of the bacteria in the insect cadaver.

  10. Localization of acid phosphatase activity in the apoplast of root nodules of pea (Pisum sativum

    Directory of Open Access Journals (Sweden)

    Marzena Sujkowska

    2011-01-01

    Full Text Available Changes in the activity of acid phosphatase (AcPase in the apoplast of pea root nodule were investigated. The activity was determined using lead and cerium methods. The results indicated a following sequence of AcPase activity appearance during the development of the infection thread: 1 low AcPase activity appears in the outer part of cells of symbiotic bacteria; 2 bacteria show increased AcPase activity, and the enzyme activity appears in the thread walls; 3 activity exhibits also matrix of the infection thread; 4 bacteria just before their release from the infection threads show high AcPase activity; 5 AcPase activity ceases after bacteria transformation into bacteroids. The increase in bacterial AcPase activity may reflect a higher demand for inorganic phosphorus necessary for propagation of the bacteria within the infection threads and/or involved in bacteria release from the infection threads.

  11. Application of Scharer's quantitative method for the determination of residual alkaline phosphatase activity in standard Minas

    Directory of Open Access Journals (Sweden)

    C.F. Soares

    2013-08-01

    Full Text Available Milk pasteurization is a critical issue in the dairy industry, and failures in this process can affect final product safety. Scharer's enzymatic method is still traditionally used to verify pasteurization efficiency compliance, and it is based on screening for residual alkaline phosphatase in milk. Although several methods are used to quantify enzymatic activity to assess milk pasteurization efficiency, there is a small amount of published data regarding the use of these methods to quantify alkaline phosphatase in cheese. In this study, the Scharer's modified method was used to determine the levels of residual alkaline phosphatase in standard minas cheese, before and after 20 days of ripening. The cheeses were made using raw or pasteurized milk with the addition of different concentrations of raw milk (0; 0.05%; 0.10%; 0.20%; and 0.50%. In the fresh cheese samples, the method showed a sensitivity of only 0.50% with the addition of raw milk to the pasteurized milk used to make cheese. In addition, levels of up 0.20% of raw milk in pasteurized milk, the concentrations of phenol was inferior to 1μg phenol/g of dairy product which is the preconized indicator value for adequate pasteurization.

  12. SAV1 promotes Hippo kinase activation through antagonizing the PP2A phosphatase STRIPAK

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sung Jun [Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States; Ni, Lisheng [Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States; Osinski, Adam [Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States; Tomchick, Diana R. [Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States; Brautigam, Chad A. [Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States; Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States; Luo, Xuelian [Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States

    2017-10-24

    The Hippo pathway controls tissue growth and homeostasis through a central MST-LATS kinase cascade. The scaffold protein SAV1 promotes the activation of this kinase cascade, but the molecular mechanisms remain unknown. Here, we discover SAV1-mediated inhibition of the PP2A complex STRIPAKSLMAP as a key mechanism of MST1/2 activation. SLMAP binding to autophosphorylated MST2 linker recruits STRIPAK and promotes PP2A-mediated dephosphorylation of MST2 at the activation loop. Our structural and biochemical studies reveal that SAV1 and MST2 heterodimerize through their SARAH domains. Two SAV1–MST2 heterodimers further dimerize through SAV1 WW domains to form a heterotetramer, in which MST2 undergoes trans-autophosphorylation. SAV1 directly binds to STRIPAK and inhibits its phosphatase activity, protecting MST2 activation-loop phosphorylation. Genetic ablation of SLMAP in human cells leads to spontaneous activation of the Hippo pathway and alleviates the need for SAV1 in Hippo signaling. Thus, SAV1 promotes Hippo activation through counteracting the STRIPAKSLMAP PP2A phosphatase complex.

  13. Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest

    Directory of Open Access Journals (Sweden)

    Kristine G. Cabugao

    2017-10-01

    Full Text Available Tropical forests generally occur on highly weathered soils that, in combination with the immobility of phosphorus (P, often result in soils lacking orthophosphate, the form of P most easily metabolized by plants and microbes. In these soils, mineralization of organic P can be the major source for orthophosphate. Both plants and microbes encode for phosphatases capable of mineralizing a range of organic P compounds. However, the activity of these enzymes depends on several edaphic factors including P availability, tree species, and microbial communities. Thus, phosphatase activity in both roots and the root microbial community constitute an important role in P mineralization and P nutrient dynamics that are not well studied in tropical forests. To relate phosphatase activity of roots and bacteria in tropical forests, we measured phosphatase activity in roots and bacterial isolates as well as bacterial community composition from the rhizosphere. Three forests in the Luquillo Mountains of Puerto Rico were selected to represent a range of soil P availability as measured using the resin P method. Within each site, a minimum of three tree species were chosen to sample. Root and bacterial phosphatase activity were both measured using a colorimetric assay with para-nitrophenyl phosphate as a substrate for the phosphomonoesterase enzyme. Both root and bacterial phosphatase were chiefly influenced by tree species. Though tree species was the only significant factor in root phosphatase activity, there was a negative trend between soil P availability and phosphatase activity in linear regressions of average root phosphatase and resin P. Permutational multivariate analysis of variance of bacterial community composition based on 16S amplicon sequencing indicated that bacterial composition was strongly controlled by soil P availability (p-value < 0.05. These results indicate that although root and bacterial phosphatase activity were influenced by tree species

  14. [Activities and properties of glucose-6-phosphatase of turbellaria Phagocata sibirica and cestodes Bothriocephalus scorpii].

    Science.gov (United States)

    Burenina, E A

    2009-01-01

    There were studied activities and properties of mitochondrial and microsomal glucose-6-phosphatases (G6Pases) in free living turbellaria Phagocata sibirica and cestodes Bothriocephalus scorpii. Action of various effectors (sodium fluoride, glucose, HCO3-, citrate, Cu2+, DTT, EDTA, ATP, AFP) on the enzyme activity was studied. The obtained results and literature data demonstrate that G6Pase is present in various muscles of representatives of the animal kingdom. The conclusion can be made that invertebrate G6Pase releases glucose from glycogen and gluconeogenic precursors.

  15. Distribution of Phosphate Solubilizing Bacteria and Soil Phosphatase Activity in Different Land Uses

    Directory of Open Access Journals (Sweden)

    M. R. Sarikhani

    2016-09-01

    Full Text Available Introduction: Phosphorous is one of the essential macronutrients for plant growth and development but its mobility in soil is very low. The utilization of the soil biological potential, in particular phosphate solubilizing bacteria, is an efficient way which can be used for exploiting available sources of phosphorous in the soil. The principal mechanism for mineral phosphate solubilization is the production of organic acid, and acid and alkaline phosphatases play a major role in the mineralization of organic phosphorous in the soil. Presence and distribution of phosphate solubilizing bacteria in the soil and soil phosphatase activities is influenced by soil conditions such as climate, soil type, vegetation and land uses. In order to understand the relationships and considering the importance of the subject, the soil samples were chosen from two different climates; semi-moist (Fandoghlou-Ardabil and semi-arid (Namin- Ardabil under culture of legumes, cereals and uncultivated areas, in this experiment. Materials and Methods: In order to study the effects of different land uses, climate conditions and soil physicochemical properties on phosphate solubilizing microorganism (PSM distribiution and soil acid and alkaline phosphatase activity, a factorial experiment based on completely randomized design was performed with considering three different land uses (including legumes, cereals and wasteland and two climate conditions (semi-moist: Fandoghlu- Ardabil and semi-arid: Namin-Ardabil. Four composite soil samples (0-25 cm were taken from each land uses. Finally, a total number of 24 soil samples were used to enumerate phosphate solubilizng bacteria and evaluate soil phosphatase activities. The enumeration and selection of bacteria in the mineral Sperber medium was done by attention to the clear zone production in the presence of tri-calcium phosphate and in organic sperber (IHP+BCIP due to blue phenotype of grown colonies. Also, phosphatase activity

  16. Changes phosphorus associated to phosphatase activity because of application of carbon, nitrogen and manure

    Science.gov (United States)

    Paredes, Cecilia; Gianfreda, Liliana; Mora, María de la Luz

    2015-04-01

    The Chilean Andisols are of great importance in the economy of southern Chile supporting the bulk of agricultural production. The major characteristics of Chilean volcanic soils are the high adsorption capacity of P with a concomitant low P availability to plants. Studies preliminary using dairy cattle dung suggest that we can improve P availability using organic P sources within the soil because of microorganism. Phosphorous solubilization by microorganisms is a complex phenomenon, which depends on many factors such as nutritional, physiological and growth condition of the culture. The principal mechanism for mineral phosphate solubilization is the production of organic acids where the enzyme phosphatases play a major role in the mineralization of organic phosphorous in soil. The objective of this study was to evaluate changes in soil phosphorus fractions due to application the cattle dung, glucose, nitrogen (N) and phosphorus (P). In this experiment we incubated soil samples with 300 g of cattle dung, 30 mg kg-1 of N and P and 1000 mg glucose kg-1. The soil samples were moistened to field capacity and incubated in plastic bags to room temperature by different time. The changes in P forms in soil were monitored through the Hedley fractionation procedure and phosphatase activity. Our preliminary results indicated that the application of cattle dung, glucose nitrogen and phosphorus, caused the increased phosphatase activity until to 7 days and then apparently return to normal values. Interestingly, we observed a rise in the inorganic P fraction extracted by NaHCO3 in the same period. In summary, the increase biological activity by carbon and nitrogen increase P availability. Acknowledgements: The authors thank Fondecyt 1141247 Project.

  17. A DNA 3′-phosphatase functions in active DNA demethylation in Arabidopsis

    OpenAIRE

    Martínez-Macías, María Isabel; Qian, Weiqiang; Miki, Daisuke; Pontes, Olga; Liu, Yunhua; Tang, Kai; Liu, Renyi; Morales-Ruiz, Teresa; Ariza, Rafael R.; Roldán-Arjona, Teresa; Zhu, Jian-Kang

    2012-01-01

    DNA methylation is an important epigenetic mark established by the combined actions of methylation and demethylation reactions. Plants use a base excision repair pathway for active DNA demethylation. After 5-methylcytosine removal, the Arabidopsis DNA glycosylase/lyase ROS1 incises the DNA backbone and part of the product has a single-nucleotide gap flanked by 3′- and 5′-phosphate termini. Here we show that the DNA phosphatase ZDP removes the blocking 3′-phosphate, allowing subsequent DNA pol...

  18. The Association of Endothelin-1 Signaling with Bone Alkaline Phosphatase Expression and Protumorigenic Activities in Canine Osteosarcoma.

    Science.gov (United States)

    Neumann, Z L; Pondenis, H C; Masyr, A; Byrum, M L; Wycislo, K L; Fan, T M

    2015-01-01

    Canine osteosarcoma (OS) is an aggressive sarcoma characterized by pathologic skeletal resorption and pulmonary metastases. A number of negative prognostic factors, including bone alkaline phosphatase, have been identified in dogs with OS, but the underlying biologic factors responsible for such observations have not been thoroughly investigated. Endothelin-1-mediated signaling is active during bone repair, and is responsible for osteoblast migration, survival, proliferation, and bone alkaline phosphatase expression. The endothelin-1 signaling axis is active in canine OS cells, and this pathway is utilized by malignant osteoblasts for promoting cellular migration, survival, proliferation, and bone alkaline phosphatase activities. 45 dogs with appendicular OS. The expressions of endothelin-1 and endothelin A receptor were studied in OS cell lines and in samples from spontaneously occurring tumors. Activities mediated by endothelin-1 signaling were investigated by characterizing responses in 3 OS cell lines. In 45 dogs with OS, bone alkaline phosphatase concentrations were correlated with primary tumor osteoproductivity. Canine OS cells express endothelin-1 and endothelin A receptor, and this signaling axis mediates OS migration, survival, proliferation, and bone alkaline phosphatase activities. In OS-bearing dogs, circulating bone alkaline phosphatase activities were positively correlated with primary tumor relative bone mineral densities. Canine OS cells express endothelin-1 and functional endothelin A receptors, with the potential for a protumorigenic signaling loop. Increases in bone alkaline phosphatase activity are associated with osteoblastic OS lesions, and might be an epiphenomenon of active endothelin-1 signaling or excessive osteoproduction within the localized bone microenvironment. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  19. Ratiometric detection of copper ions and alkaline phosphatase activity based on semiconducting polymer dots assembled with rhodamine B hydrazide.

    Science.gov (United States)

    Sun, Junyong; Mei, Han; Gao, Feng

    2017-05-15

    The rational surface functionalization of semiconducting polymer dots (Pdots) has attracted much attention to extend their applications in fabricating chemo/biosensing platform. In this study, a novel ratiometric fluorescent sensing platform using functionalized Pdots as probes for fluorescence signal transmission has been designed for sensing Cu(Ⅱ) and activity of alkaline phosphatase (ALP) with high selectivity and enhanced sensitivity. The highly fluorescent Pdots were firstly prepared with Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1',3}-thiadiazole)] (PFBT) via nanoprecipitation method, and then assembled with non-fluorescent rhodamine B hydrazide (RB-hy), which shows special binding activity to Cu(Ⅱ), through adsorption process to obtain functionalized nanohybrids, Pdots@RB-hy. As thus, a FRET donors/acceptors pair, in which PFBT Pdots act as energy donors while RB-hy-Cu(II) complexes act as energy acceptors were constructed. On the basis of the varies in fluorescence intensities of donors/acceptors in the presence of different amounts of Cu(II), a ratiometric method for sensing Cu(II) has been proposed. The proposed ratiometric Cu(II) sensor shows a good linear detection range from 0.05 to 5μM with a detection limit of 15nM. Furthermore, using the Pdots@RB-hy-Cu(II) system as signal transducer, a ratiometric sensing for alkaline phosphatase (ALP) activity has also been established with pyrophosphate (PPi) as substrates. The constructed ratiometric sensor of ALP activity displays a linear detection range from 0.005 to 15UL -1 with a detection limit of 0.0018UL -1 . The sensor was further successfully used for ALP activity detection in human serum with satisfactory results. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Optimization of extraction parameters of PTP1β (protein tyrosine phosphatase 1β), inhibitory polyphenols, and anthocyanins from Zea mays L. using response surface methodology (RSM).

    Science.gov (United States)

    Hwang, Seung Hwan; Kwon, Shin Hwa; Wang, Zhiqiang; Kim, Tae Hyun; Kang, Young-Hee; Lee, Jae-Yong; Lim, Soon Sung

    2016-08-26

    Protein tyrosine phosphatase expressed in insulin-sensitive tissues (such as liver, muscle, and adipose tissue) has a key role in the regulation of insulin signaling and pathway activation, making protein tyrosine phosphatase a promising target for the treatment of type 2 diabetes mellitus and obesity and response surface methodology (RSM) is an effective statistical technique for optimizing complex processes using a multi-variant approach. In this study, Zea mays L. (Purple corn kernel, PCK) and its constituents were investigated for protein tyrosine phosphatase 1β (PTP1β) inhibitory activity including enzyme kinetic study and to improve total yields of anthocyanins and polyphenols, four extraction parameters, including temperature, time, solid-liquid ratio, and solvent volume, were optimized by RSM. Isolation of seven polyphenols and five anthocyanins was achieved by PTP1β assay. Among them, cyanidin-3-(6"malonylglucoside) and 3'-methoxyhirsutrin showed the highest PTP1β inhibition with IC50 values of 54.06 and 64.04 μM, respectively and 4.52 mg gallic acid equivalent/g (GAE/g) of total polyphenol content (TPC) and 43.02 mg cyanidin-3-glucoside equivalent/100 g (C3GE/100g) of total anthocyanin content (TAC) were extracted at 40 °C for 8 h with a 33 % solid-liquid ratio and a 1:15 solvent volume. Yields were similar to predictions of 4.58 mg GAE/g of TPC and 42.28 mg C3GE/100 g of TAC. These results indicated that PCK and 3'-methoxyhirsutrin and cyanidin-3-(6"malonylglucoside) might be active natural compounds and could be apply by optimizing of extraction process using response surface methodology.

  1. Mechanics of active surfaces

    Science.gov (United States)

    Salbreux, Guillaume; Jülicher, Frank

    2017-09-01

    We derive a fully covariant theory of the mechanics of active surfaces. This theory provides a framework for the study of active biological or chemical processes at surfaces, such as the cell cortex, the mechanics of epithelial tissues, or reconstituted active systems on surfaces. We introduce forces and torques acting on a surface, and derive the associated force balance conditions. We show that surfaces with in-plane rotational symmetry can have broken up-down, chiral, or planar-chiral symmetry. We discuss the rate of entropy production in the surface and write linear constitutive relations that satisfy the Onsager relations. We show that the bending modulus, the spontaneous curvature, and the surface tension of a passive surface are renormalized by active terms. Finally, we identify active terms which are not found in a passive theory and discuss examples of shape instabilities that are related to active processes in the surface.

  2. Water molecule network and active site flexibility of apo protein tyrosine phosphatase 1B

    DEFF Research Database (Denmark)

    Pedersen, A.K.; Peters, Günther H.J.; Møller, K.B.

    2004-01-01

    the conformation and flexibility of active-site residues as well as the water-molecule network, is a key issue in understanding ligand binding and enzyme kinetics and in structure-based drug design. A 1.95 Angstrom apo PTP1B structure has been obtained, showing four highly coordinated water molecules in the active......Protein tyrosine phosphatase 1B (PTP1B) plays a key role as a negative regulator of insulin and leptin signalling and is therefore considered to be an important molecular target for the treatment of type 2 diabetes and obesity. Detailed structural information about the structure of PTP1B, including......-site pocket of the enzyme; hence, the active site is highly solvated in the apo state. Three of the water molecules are located at positions that approximately correspond to the positions of the phosphate O atoms of the natural substrate phosphotyrosine and form a similar network of hydrogen bonds. The active...

  3. A novel transcription factor involved in plant defense endowed with protein phosphatase activity

    Science.gov (United States)

    Carrasco, José L.; Ancillo, Gema; Mayda, Esther; Vera, Pablo

    2003-01-01

    In plants, expression of a disease-resistance character following perception of a pathogen involves massive deployment of transcription-dependent defenses. Thus, if rapid and effective defense responses have to be achieved, it is crucial that the pathogenic signal is transduced and amplified through pre-existing signaling pathways. Reversible phosphorylation of specific transcription factors, by a concerted action of protein kinases and phosphatases, may represent a mechanism for rapid and flexible regulation of selective gene expression by environmental stimuli. Here we identified a novel DNA-binding protein from tobacco plants, designated DBP1, with protein phosphatase activity, which binds in a sequence-specific manner to a cis- acting element of a defense-related gene and participates in its transcriptional regulation. This finding helps delineate a terminal event in a signaling pathway for the selective activation of early transcription-dependent defense responses in plants, and suggests that stimulus-dependent reversible phosphorylation of regulatory proteins may occur directly in a transcription protein–DNA complex. PMID:12839999

  4. Host Plant Effects on Alkaline Phosphatase Activity in the Whiteflies, Bemisia tabaci Biotype B and Trialeurodes vaporariorum

    Science.gov (United States)

    Yan, Ying; Peng, Lu; Liu, Wan-Xue; Wan, Fang-Hao; Harris, Marvin K.

    2011-01-01

    Bemisia tabaci (Gennadius) B-biotype and Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) often coexist on greenhouse-grown vegetable crops in northern China. The recent spread of B. tabaci B-biotype has largely replaced T. vaporariorum, and B-biotype now overlaps with T. vaporariorum where common hosts occur in most invaded areas. The impact of the B-biotype on the agro eco system appears to be widespread, and involves the ability to compete with and perhaps replace other phytophages like T. vaporariorum. An emerging hypothesis is that the B-biotype is physiologically superior due at least in part to an improved ability to metabolically utilize the alkaline phosphatase pathway. To test this hypothesis, alkaline phosphatase activity was studied in the B-biotype and T. vaporariorum after feeding on a number of different hosts for a range of durations, with and without host switching. Alkaline phosphatase activity in T. vaporariorum was 1.45 to 2.53-fold higher than that of the B-biotype when fed on tomato for 4 and 24 h, or switched from tomato to cotton and cabbage for the same durations. However, alkaline phosphatase activity in the B-biotype was 1.40 to 3.35-fold higher than that of T. vaporariorum when the host switching time was ∼72 and ∼120 h on the same plant. Both short-term (4 h) and long-term (72 h) switching of plant hosts can significantly affect the alkaline phosphatase activity in the two species. After ∼120 h, feeding on tomato and cotton alkaline phosphatase activity in the B-biotype was significantly higher than that of T. vaporariorum. It was shown that alkaline phosphatase aids the species feeding on different plant species, and that the B-biotype is physiologically superior to T. vaporariorum in utilizing the enzyme compared to T. vaporariorum over longer periods of feeding. PMID:21521136

  5. Hemagglutinating and acid phosphatase (AcPASE activities in developing seedlings of four species of Cucurbitaceae

    Directory of Open Access Journals (Sweden)

    Irena Lorenc-Kubis

    2014-01-01

    Full Text Available The acid phosphatase and hemagglutinating activities of four species of Cucurbitaceae were determined during seeds germination and seedlings development. In all cases traces of enzyme and hemagglutinating activities were found in dry and imbibided seeds. In developing seedlings of Cucumis sativus the activities increased to maximum on the 3rd day while in other species on the 6th day of germination and than fell down. Dot blot and Western blot techniques have shown that in seeds and seedlings of all investigated species present were proteins which cross-reacted with antibodies raised against lectins: CLBa and Con A. It has been shown that proteins from seeds and seedlings of Cucurbita maxima var. bambino, Cucurbita pepo var. giromontia and Cucumis sativus had more pronounced antigenical similarity to lectin CLBa (from Cucurbitaceae than Con A, while proteins from cotyledons of Cucurbita pepo var. patissonina reacted better with antibodies raised against Con A (the lectin from Papilionaceae than with CLBa.

  6. Protein phosphatase 2A isotypes regulate cell surface expression of the T cell receptor

    DEFF Research Database (Denmark)

    Lauritsen, Jens Peter Holst; Menné, C; Kastrup, J

    2001-01-01

    show that inhibition of the serine/threonine protein phosphatase PP2A family had a biphasic effect on TCR expression. Thus, low concentrations of PP2A inhibitors induced TCR down-regulation, whereas higher concentrations of PP2A inhibitors induced TCR up-regulation. The effect of PP2A inhibition...... regulatory role for PP2A in both exocytosis and endocytosis....

  7. Diarylsulfonamides and their bioisosteres as dual inhibitors of alkaline phosphatase and carbonic anhydrase: Structure activity relationship and molecular modelling studies.

    Science.gov (United States)

    Al-Rashida, Mariya; Ejaz, Syeda Abida; Ali, Sharafat; Shaukat, Aisha; Hamayoun, Mehwish; Ahmed, Maqsood; Iqbal, Jamshed

    2015-05-15

    The effect of bioisosteric replacement of carboxamide linking group with sulfonamide linking group, on alkaline phosphatase (AP) and carbonic anhydrase (CA) inhibition activity of aromatic benzenesulfonamides was investigated. A series of carboxamide linked aromatic benzenesulfonamides 1a-1c, 2a-2d and their sulfonamide linked bioisosteres 3a-3d, 4a-4d was synthesized and evaluated for inhibitory activity against bovine tissue non-specific alkaline phosphatase (TNAP), intestinal alkaline phosphatase (IAP) and bCA II. A significant increase in CA inhibition activity was observed upon bioisosteric replacement of carboxamide linking group with a sulfonamide group. Some of these compounds were identified as highly potent and selective AP inhibitors. Compounds 1b, 2b, 3d, 4d 5b and 5c were found to be selective bTNAP inhibitors, whereas compounds 1a, 1c, 2a, 2c, 2d, 3a, 3c, 4a, 4b, 4c, 5a were found to be selective bIAP inhibitors. For most active AP inhibitor 3b, detailed kinetic studies indicated a competitive mode of inhibition against tissue non-specific alkaline phosphatase (TNAP) and non-competitive mode of inhibition against intestinal alkaline phosphatase (IAP). Molecular docking studies were carried out to rationalize important binding site interactions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Meroterpenoids with Protein Tyrosine Phosphatase 1B Inhibitory Activity from a Hyrtios sp. Marine Sponge.

    Science.gov (United States)

    Wang, Jie; Mu, Feng-Rong; Jiao, Wei-Hua; Huang, Jian; Hong, Li-Li; Yang, Fan; Xu, Ying; Wang, Shu-Ping; Sun, Fan; Lin, Hou-Wen

    2017-09-22

    Three new meroterpenoids, hyrtiolacton A (1), nakijinol F (2), and nakijinol G (3), along with three known ones, nakijinol B (4), nakijinol E (5), and dactyloquinone A (6), were isolated and characterized from a Hyrtios sp. marine sponge collected from the South China Sea. The new structures were determined based on extensive analysis of HRESIMS and NMR data, and their absolute configurations were assigned by a combination of single-crystal X-ray diffraction and electronic circular dichroism analyses. Hyrtiolacton A (1) represents an unprecedented meroterpenoid featuring an unusual 2-pyrone attached to the sesquiterpene core, which is the first example of a pyrone-containing 4,9-friedodrimane-type sesquiterpene. These compounds were evaluated for their protein tyrosine phosphatase (PTP1B) inhibitory and cytotoxic activities. Nakijinol G (3) showed PTP1B inhibitory activity with an IC 50 value of 4.8 μM but no cytotoxicity against four human cancer cell lines.

  9. Direct regulation of transforming growth factor β-induced epithelial-mesenchymal transition by the protein phosphatase activity of unphosphorylated PTEN in lung cancer cells.

    Science.gov (United States)

    Kusunose, Masaaki; Hashimoto, Naozumi; Kimura, Motohiro; Ogata, Ryo; Aoyama, Daisuke; Sakamoto, Koji; Miyazaki, Shinichi; Ando, Akira; Omote, Norihito; Imaizumi, Kazuyoshi; Kawabe, Tsutomu; Hasegawa, Yoshinori

    2015-12-01

    Transforming growth factor β (TGFβ) causes the acquisition of epithelial-mesenchymal transition (EMT). Although the tumor suppressor gene PTEN (phosphatase and tensin homologue deleted from chromosome 10) can negatively regulate many signaling pathways activated by TGFβ, hyperactivation of these signaling pathways is observed in lung cancer cells. We recently showed that PTEN might be subject to TGFβ-induced phosphorylation of its C-terminus, resulting in a loss of its enzyme activities; PTEN with an unphosphorylated C-terminus (PTEN4A), but not PTEN wild, inhibits TGFβ-induced EMT. Nevertheless, whether or not the blockade of TGFβ-induced EMT by the PTEN phosphatase activity might be attributed to the unphosphorylated PTEN C-terminus itself has not been fully determined. Furthermore, the lipid phosphatase activity of PTEN is well characterized, whereas the protein phosphatase activity has not been determined. By using lung cancer cells carrying PTEN domain deletions or point mutants, we investigated the role of PTEN protein phosphatase activities on TGFβ-induced EMT in lung cancer cells. The unphosphorylated PTEN C-terminus might not directly retain the phosphatase activities and repress TGFβ-induced EMT; the modification that keeps the PTEN C-terminus not phosphorylated might enable PTEN to retain the phosphatase activity. PTEN4A with G129E mutation, which lacks lipid phosphatase activity but retains protein phosphatase activity, repressed TGFβ-induced EMT. Furthermore, the protein phosphatase activity of PTEN4A depended on an essential association between the C2 and phosphatase domains. These data suggest that the protein phosphatase activity of PTEN with an unphosphorylated C-terminus might be a therapeutic target to negatively regulate TGFβ-induced EMT in lung cancer cells. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

  10. Alkaline phosphatase activity at the southwest coast of India: A comparison of locations differently affected by upwelling

    Science.gov (United States)

    Mamatha, S. S.; Malik, Ashish; Varik, Sandesh; Parvathi, V.; Jineesh, V. K.; Gauns, Mangesh U.; LokaBharathi, P. A.

    2015-01-01

    The realization of the potential importance of phosphorus (P) as a limiting nutrient in marine ecosystem is increasing globally. Hence, the contribution of biotic variables in mobilizing this nutrient would be relevant especially in productive coastal waters. As alkaline phosphatase activity (APA) indicates the status of P for primary production in aquatic environments, we asked the following question: is the level of APA indicative of P sufficiency or deficiency in coastal waters, especially, where upwelling is a regular phenomenon? Therefore, we have examined the total APA, chlorophyll a along with phosphatase producing bacteria (PPB) and related environmental parameters from nearshore to offshore in coastal waters off Trivandrum and Kochi regions differently affected by upwelling during the onset of monsoon. Off Trivandrum, APA in the offshore waters of 5-m layer at 2.23 μM P h- 1 was > 4 times higher than nearshore. Thus, low APA could be indicative of P sufficiency in coastal waters and higher activity suggestive of deficiency in offshore waters off Trivandrum. In contrast, there was less difference in APA between near and offshore surface waters off Kochi. Our results show that the regions differently affected by upwelling respond differently according to ambient P concentration, distance from shore or depth of water. These observations could apparently be applicable to other coastal systems as well, where gradients in upwelling and phosphate runoff have been noticed. Further studies on other transects would throw more light on the extent and direction of the relationship between APA and ambient P concentration. Such studies would help in understanding the level of control of this nutrient on the productivity of coastal waters.

  11. The Phosphatase Inhibitor Calyculin-A Impairs Clot Retraction, Platelet Activation, and Thrombin Generation

    Directory of Open Access Journals (Sweden)

    Renáta Hudák

    2017-01-01

    Full Text Available The aim of this study was to investigate the effect of the serine/threonine protein phosphatase inhibitor, calyculin-A (CLA, on clot formation and on the procoagulant activity of human platelets. Platelet-rich plasma (PRP samples were preincubated with buffer or CLA and subsequently platelets were activated by the protease-activated receptor 1 (PAR-1 activator, thrombin receptor activating peptide (TRAP. Clot retraction was detected by observing clot morphology up to 1 hour, phosphatidylserine- (PS- expression was studied by flow cytometry, and thrombin generation was measured by a fluorimetric assay. For the intracellular Ca2+ assay, platelets were loaded with calcium-indicator dyes and the measurements were carried out using a ratiometric method with real-time confocal microscopy. CLA preincubation inhibited clot retraction, PS-expression, and thrombin formation. TRAP activation elicited Ca2+ response and PS-expression in a subset of platelets. The activated PRP displayed significantly faster and enhanced thrombin generation compared to nonactivated samples. CLA pretreatment abrogated PS-exposure and clot retraction also in TRAP-activated samples. As a consequence of the inhibitory effect on calcium elevation and PS-expression, CLA significantly downregulated thrombin generation in PRP. Our results show that CLA pretreatment may be a useful tool to investigate platelet activation mechanisms that contribute to clot formation and thrombin generation.

  12. Tissue-nonspecific alkaline phosphatase with an Asp(289)-->Val mutation fails to reach the cell surface and undergoes proteasome-mediated degradation.

    Science.gov (United States)

    Ishida, Yoko; Komaru, Keiichi; Ito, Masahiro; Amaya, Yoshihiro; Kohno, Shoji; Oda, Kimimitsu

    2003-07-01

    A missense mutation in the gene of tissue-nonspecific alkaline phosphatase, which replaces aspartic acid at position 289 with valine [TNSALP (D289V)], was reported in a lethal hypophosphatasia patient [Taillandier, A. et al. (1999) Hum. Mut. 13, 171-172]. To define the molecular defects of TNSALP (D289V), this mutant protein in transiently transfected COS-1 cells was analyzed biochemically and morphologically. TNSALP (D289V) exhibited no alkaline phosphatase activity and mainly formed a disulfide-linked high molecular mass aggregate. Cell-surface biotinylation, digestion with phosphatidylinositol-specific phospholipase C and an immunofluorescence study showed that the mutant protein failed to appear on the cell surface and was accumulated intracellularly. In agreement with this, pulse/chase experiments demonstrated that TNSALP (D289V) remained endo-beta-N-acetyl- glucosaminidase H-sensitive throughout the chase and was eventually degraded, indicating that the mutant protein is unable to reach the medial-Golgi. Proteasome inhibitors strongly blocked the degradation of TNSALP (D289V), and furthermore the mutant protein was found to be ubiquitinated. Besides, another naturally occurring TNSALP with a Glu(218)-->Gly mutation was also found to be polyubiquitinated and degraded in the proteasome. Since the acidic amino acids at positions 218 and 289 of TNSALP are thought to be directly involved in the Ca(2+) coordination, these results suggest the critical importance of calcium binding in post-translational folding and assembly of the TNSALP molecule.

  13. Growth and extracellular phosphatase activity of arbuscular mycorrhizal hyphae as influenced by soil organic matter

    DEFF Research Database (Denmark)

    Joner, E.J.; Jakobsen, I.

    1995-01-01

    precipitation leached through the soil, or indoor at constant moisture) with or without 9% (w/w) chopped wheat straw plus mineral N. Then the soils were partially sterilized and placed in two-compartment pots where mycorrhizal or non-mycorrhizal cucumber plants were grown in one root compartment (RC), and soils......Two experiments were set up to investigate the influence of soil organic matter on growth of arbuscular mycorrhizal (AM) hyphae and concurrent changes in soil inorganic P, organic P and phosphatase activity. A sandy loam soil was kept for 14 months under two regimes (outdoor where surplus...... differing in organic matter were placed in six parallel hyphal compartments (HC) separated from the RC with a 37 mu m mesh. In the first experiment, using Glomus caledonium, hyphal length densities were measured in the HC after 31 days. Added straw increased hyphal length densities by 34 and 62% for soil...

  14. Effects of synthetic detergents on in vivo activity of tissue phosphatases and succinic dehydrogenase from Mystus vittatus

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, D.; Verma, S.R.

    1981-05-01

    African catfish (Mystus vittatus) were exposed to three sub-lethal concentrations of Swascofix E45 (13.8, 9.2 and 4.6 mg/l) and Swascol 3L (69.3, 46.2 and 23.1 mg/l) for 15 and 30 days, and their effects on alkaline and acid phosphatase, and succinic dehydrogenase in liver, kidney and intestine were measured. The enzymes were found to be inhibited in all the tissues. Maximum inhibition (38.44%) was observed in liver alkaline phosphatase activity after 30 days with the highest concentration of Swascofix E45 and the lowest inhibition (0.118%) was found in kidney acid phosphatase activity with the lowest concentration of Swascol 3L after 15 days. Insignificant enzyme stimulation in some cases was also observed.

  15. Correlation of alkaline phosphatase activity to clinical parameters of inflammation in smokers suffering from chronic periodontitis

    Directory of Open Access Journals (Sweden)

    Vishakha Grover

    2016-01-01

    Full Text Available Context: Current clinical periodontal diagnostic techniques emphasize the assessment of clinical and radiographic signs of periodontal diseases which can provide a measure of history of disease. Hence, new methodologies for early identification and determination of periodontal disease activity need to be explored which will eventually result in expedited treatment. Aim: To evaluate the correlation of alkaline phosphatase (ALP activity in gingival crevicular fluid (GCF to clinical parameters of periodontal inflammation in smokers with chronic periodontitis. Materials and Methods: Study population included 15 smoker male patients in the age group of 35–55 years suffering from moderate generalized chronic periodontitis with history of smoking present. Following parameters were evaluated at baseline, 1 month and 3 months after scaling and root planing: plaque index, bleeding index, probing pocket depth (PD, relative attachment level (RAL, and GCF ALP activity. Statistical Analysis Used: Independent variables for measurements over time were analyzed by using Wilcoxon signed rank test. Results: A statistically significant reduction in all the clinical parameters and GCF ALP activity was observed from baseline to 1 month and 3 months. A correlation was observed between change in GCF ALP activity and PD reduction as well as gain in RAL at 3 months. Conclusion: The present study emphasizes that total ALP activity could be used as a marker for periodontal disease activity in smokers. Estimation of changes in the levels of this enzyme has a potential to aid in the detection of progression of periodontal disease and monitoring the response to periodontal therapy.

  16. Obesity Increases Mitogen-Activated Protein Kinase Phosphatase-3 Levels in the Hypothalamus of Mice

    Directory of Open Access Journals (Sweden)

    Bárbara de A. Rodrigues

    2017-10-01

    Full Text Available Mitogen-activated Protein Kinase Phosphatase 3 (MKP-3 has been involved in the negative regulation of insulin signaling. The absence of MKP-3 is also associated with reduced adiposity, increased energy expenditure and improved insulin sensitivity. The MKP-3 is known as the main Erk1/2 phosphatase and FoxO1 activator, which has repercussions on the gluconeogenesis pathway and hyperglycemia in obese mice. Recently, we showed that MKP-3 overexpression decreases FoxO1 phosphorylation in the hypothalamus of lean mice. However, the hypothalamic interaction between MKP-3 and FoxO1 during obesity was not investigated yet. Here, the MKP-3 expression and the effects on food intake and energy expenditure, were investigated in high-fat diet-induced obese mice. The results indicate that obesity in mice increased the MKP-3 protein content in the hypothalamus. This hypothalamic upregulation led to an increase of food intake, adiposity, and body weight. Furthermore, the obese mice with increased MKP-3 showed an insulin signaling impairment with reduction of insulin-induced FoxO1 and Erk1/2 phosphorylation in the hypothalamus. Moreover, a bioinformatics analysis of data demonstrated that hypothalamic MKP-3 mRNA levels were positively correlated with body weight and negatively correlated to oxygen consumption (VO2 in BXD mice. Taken together, our study reports that obesity is associated with increased protein levels of hypothalamic MKP-3, which is related to the reduction of FoxO1 and Erk1/2 phosphorylation in the hypothalamus as well as to an increase in body weight and a reduction in energy expenditure.

  17. Phosphatidylinositol 3'-kinase and tyrosine-phosphatase activation positively modulate Convulxin-induced platelet activation. Comparison with collagen.

    Science.gov (United States)

    Lagrue, A H; Francischetti, I M; Guimarães, J A; Jandrot-Perrus, M

    1999-04-01

    In this report we have studied the role of phosphatidylinositol 3'-kinase (PI3-K) and tyrosine phosphatase activation on platelet activation by Convulxin (Cvx). Wortmannin, a specific PI3-K inhibitor, and phenylarsine oxide (PAO), a sulfhydryl reagent that inhibits tyrosine phosphatase (PTPase), block Cvx-induced platelet aggregation, granule secretion, inositol phosphate production, and increase in [Ca2+]i. However, PAO does not inhibit Cvx-induced tyrosine phosphorylation of platelet proteins, including Syk and PLCgamma2, but blocked collagen-induced platelet aggregation as well as tyrosine phosphorylation of PLCgamma2. In contrast, Cvx-induced PLCgamma2 tyrosyl phosphorylation was partially inhibited by wortmannin. We conclude that (i) although Cvx and collagen activate platelets by a similar mechanism, different regulatory processes are specific to each agonist; (ii) mechanisms other than tyrosine phosphorylation regulate PLCgamma2 activity; and (iii) besides protein tyrosine kinases, PI3-K (and PTPase) positively modulate platelet activation by both Cvx and collagen, and this enzyme is required for effective transmission of GPVI-Fc receptor gamma chain signal to result in full activation and tyrosine phosphorylation of PLCgamma2 in Cvx-stimulated platelets.

  18. Effects of nitrogen enrichment on phosphatase activity and nitrogen : phosphorus relationships in Cladonia portentosa.

    Science.gov (United States)

    Hogan, E J; Minnullina, G; Smith, R I; Crittenden, P D

    2010-06-01

    *Relationships between nitrogen deposition in the UK and phosphomonoesterase (PME) activity and nitrogen (N) and phosphorus (P) concentrations in Cladonia portentosa were quantified to understand factors limiting lichen growth and to further develop biomarkers for N pollution. *Lichen was collected from sites differing either in rates of wet N (NH(4)(+) + NO(3)(-)) deposition or in annual mean N concentration in rainfall based on both measured and modelled data sets. The PME activity, and total N and P concentrations were measured in specific horizontal strata in lichen mats and PME activity in the thallus was located using an enzyme-labelled fluorescent phosphatase substrate. *With an increase in modelled N deposition from 4.1 to 32.8 kg N ha(-1) yr(-1), PME activity, thallus N and N : P ratio increased by factors of 2.3, 1.4 and 1.8, respectively. Correlations with modelled data were generally stronger than with measured data and those with N deposition were stronger than those with N concentration in rainfall. The PME activity was located solely in the lichen fungus in outer regions of the thallus. *Nitrogen enrichment changes lichen N : P ratios from values typical of N limitation (for example, 10) to those indicative of P limitation (for example, 26) driving upregulation of PME activity.

  19. Liposomal C6 Ceramide Activates Protein Phosphatase 1 to Inhibit Melanoma Cells.

    Directory of Open Access Journals (Sweden)

    Fangzhen Jiang

    Full Text Available Melanoma is one common skin cancer. In the present study, the potential anti-melanoma activity by a liposomal C6 ceramide was tested in vitro. We showed that the liposomal C6 (ceramide was cytotoxic and anti-proliferative against a panel of human melanoma cell lines (SK-Mel2, WM-266.4 and A-375 and WM-115. In addition, liposomal C6 induced caspase-dependent apoptotic death in the melanoma cells. Reversely, its cytotoxicity was attenuated by several caspase inhibitors. Intriguingly, liposomal C6 was non-cytotoxic to B10BR mouse melanocytes and primary human melanocytes. Molecularly, liposomal C6 activated protein phosphatase 1 (PP1 to inactivate Akt-mammalian target of rapamycin (mTOR signaling in melanoma cells. On the other hand, PP1 shRNA knockdown or exogenous expression of constitutively activate Akt1 (CA-Akt1 restored Akt-mTOR activation and significantly attenuated liposomal C6-mediated cytotoxicity and apoptosis in melanoma cells. Our results suggest that liposomal C6 activates PP1 to inhibit melanoma cells.

  20. Epidermal growth factor receptor activation by diesel particles is mediated by tyrosine phosphatase inhibition

    International Nuclear Information System (INIS)

    Tal, Tamara L.; Bromberg, Philip A.; Kim, Yumee; Samet, James M.

    2008-01-01

    Exposure to particulate matter (PM) is associated with increased cardiopulmonary morbidity and mortality. Diesel exhaust particles (DEP) are a major component of ambient PM and may contribute to PM-induced pulmonary inflammation. Proinflammatory signaling is mediated by phosphorylation-dependent signaling pathways whose activation is opposed by the activity of protein tyrosine phosphatases (PTPases) which thereby function to maintain signaling quiescence. PTPases contain an invariant catalytic cysteine that is susceptible to electrophilic attack. DEP contain electrophilic oxy-organic compounds that may contribute to the oxidant effects of PM. Therefore, we hypothesized that exposure to DEP impairs PTPase activity allowing for unopposed basal kinase activity. Here we report that exposure to 30 μg/cm 2 DEP for 4 h induces differential activation of signaling in primary cultures of human airway epithelial cells (HAEC), a primary target cell in PM inhalation. In-gel kinase activity assay of HAEC exposed to DEPs of low (L-DEP), intermediate (I-DEP) or high (H-DEP) organic content showed differential activation of intracellular kinases. Exposure to these DEP also induced varying levels of phosphorylation of the receptor tyrosine kinase EGFR in a manner that requires EGFR kinase activity but does not involve receptor dimerization. We demonstrate that treatment with DEP results in an impairment of total and EGFR-directed PTPase activity in HAEC with a potency that is independent of the organic content of these particles. These data show that DEP-induced EGFR phosphorylation in HAEC is the result of a loss of PTPase activities which normally function to dephosphorylate EGFR in opposition to baseline EGFR kinase activity

  1. Activation of the low molecular weight protein tyrosine phosphatase in keratinocytes exposed to hyperosmotic stress.

    Directory of Open Access Journals (Sweden)

    Rodrigo A Silva

    Full Text Available Herein, we provide new contribution to the mechanisms involved in keratinocytes response to hyperosmotic shock showing, for the first time, the participation of Low Molecular Weight Protein Tyrosine Phosphatase (LMWPTP activity in this event. We reported that sorbitol-induced osmotic stress mediates alterations in the phosphorylation of pivotal cytoskeletal proteins, particularly Src and cofilin. Furthermore, an increase in the expression of the phosphorylated form of LMWPTP, which was followed by an augment in its catalytic activity, was observed. Of particular importance, these responses occurred in an intracellular milieu characterized by elevated levels of reduced glutathione (GSH and increased expression of the antioxidant enzymes glutathione peroxidase and glutathione reductase. Altogether, our results suggest that hyperosmostic stress provides a favorable cellular environment to the activation of LMWPTP, which is associated with increased expression of antioxidant enzymes, high levels of GSH and inhibition of Src kinase. Finally, the real contribution of LMWPTP in the hyperosmotic stress response of keratinocytes was demonstrated through analysis of the effects of ACP1 gene knockdown in stressed and non-stressed cells. LMWPTP knockdown attenuates the effects of sorbitol induced-stress in HaCaT cells, mainly in the status of Src kinase, Rac and STAT5 phosphorylation and activity. These results describe for the first time the participation of LMWPTP in the dynamics of cytoskeleton rearrangement during exposure of human keratinocytes to hyperosmotic shock, which may contribute to cell death.

  2. The wip1 phosphatase (PPM1D) antagonizes activation of the CHK2 tumor suppressor kinase

    International Nuclear Information System (INIS)

    Manet, Oliva-Trastoy; Berthonaud, V.; Chevalier, A.; Ducrot, C.; Marsolier-Kergoat, M.C.; Mann, C.; Leteurtre, F.

    2006-01-01

    ). Our group previously demonstrated that type 2C protein phosphatases (PP2C) Ptc2 and Ptc3 are required for DNA checkpoint inactivation after DNA double-strand break repair or adaptation in S. cerevisiae. Here we show the conservation of this pathway in mammalian cells. In response to DNA damage, ATM (ataxia telangiectasia mutated) phosphorylates the Chk2 tumor suppressor kinase at threonine 68 (Thr68), allowing Chk2 kinase dimerization and activation by auto-phosphorylations in the T-loop. The oncogenic protein Wip1, a PP2C phosphatase, binds Chk2 and de-phosphorylates phospho-Thr68. Consequently, Wip1 opposes Chk2 activation by ATM after ionizing irradiation of cells. The recombinant Chk2 protein is fully phosphorylated and activated, due to the high protein concentrations obtained during production. In vitro, Wip 1 de-phosphorylates the phospho-T68 of Chk2, but does not reduce Chk2 kinase activity on its usual GST-CDC25C substrate. These observations suggest that Wip1 phosphatase controls Chk2 activation rather than its enzymatic activity that relies on phosphorylations in the T-loop. The physiological consequences of Wip1 overexpression were tested in human adenocarcinoma cells: the HCT15 cell line. The specificities of this cell line are (i ) the absence of functional p53 proteins, leading to a G2 delay in response to a genotoxic stress, and (ii) the absence of functional Chk2 proteins, because of one CHK2 allele being unexpressed and because the second allele codes for a mutated protein that is unstable and inactive. The HCT15 cell line was complemented by a functional form of HA-Chk2 and the selected clone expresses the protein to a level similar to that observed in other cell lines. In HCT15 colorectal cancer cells corrected for functional Chk2 activity, Wip 1 modest overexpression suppressed the contribution of Chk2 to the G2/M DNA damage checkpoint. These results indicate that Wip1 is one of the phosphatases regulating the activity of Chk2 in response to DNA

  3. Interleukin 2 induces a transient downregulation of protein phosphatase 1 and 2A activity in human T cells

    DEFF Research Database (Denmark)

    Brockdorff, J; Nielsen, M; Dobson, P

    1997-01-01

    /threonine phosphatases in antigen specific, CD4+ human T cell lines. Using inhibitors of protein phosphatases 1 (PP1, PP2A, and PP2B, we provide evidence, that IL-2 induces a downregulation of PP activity in the cytoplasmic/membrane fraction. Thus, IL-2R ligation for 30 min triggers a 16 percent decrease in total PP2A...... activity (p 2A activity reaches a maximum 60 min after IL-2R ligation, and returns to baseline levels within two hours. Downregulation of PPI activity reaches a maximum after 30 min...... and is largely reversed one hour after IL-2 stimulation. As determined from immunoblotting experiments using a specific anti-PP1 or anti-PP2A antibody, the amount of PPI and PP2A recovered from cytosolic/membrane fraction remains unchanged after IL-2 treatment suggesting that the drop in PP1/PP2A activity might...

  4. Fluorometric determination of alkaline phosphatase activity in food using magnetoliposomes as on-flow microcontainer devices.

    Science.gov (United States)

    Román-Pizarro, Vanessa; Fernández-Romero, Juan Manuel; Gómez-Hens, Agustina

    2014-02-26

    Liposomes containing magnetic gold nanoparticles (AuNPs) and an enzymatic substrate (4-methylumbelliferyl-phosphate) have been used as on-flow microcontainers for reagent preconcentration in a flow injection method for the determination of alkaline phosphatase (ALP) activity. The dynamic range of the calibration graph was 6.4 × 10(-3)-0.25 U L(-1) ALP, and the detection limit was 1.9 × 10(-3) U L(-1). The precision, expressed as relative standard deviation (RSD%), was in the range of 0.7-2.4%. The overall method showed a sampling frequency of 10 h(-1). The method was applied to the determination of ALP in milk samples with recovery values ranging between 87.5 and 104.6%. The residual ALP activity in milk samples subjected to temperature treatments was also determined. The results obtained in the analysis of all milk samples were compared with those obtained by applying a previously described flow injection method.

  5. Interactive effects of temperature, ultraviolet radiation and food quality on zooplankton alkaline phosphatase activity.

    Science.gov (United States)

    Wolinski, Laura; Modenutti, Beatriz; Souza, Maria Sol; Balseiro, Esteban

    2016-06-01

    Ultraviolet Radiation (UVR) is a stressor for aquatic organisms affecting enzyme activities in planktonic populations because of the increase in reactive oxygen species. In addition, UVR exposure combined with other environmental factors (i.e. temperature and food quality) could have even higher detrimental effects. In this work, we aimed to determine the effect of UVR on somatic Alkaline Phosphatase Activity (APA) and Glutathione S-Transferase (GST) activity on the cladoceran Daphnia commutata under two different temperatures (10 °C and 20 °C) and under three food qualities (carbon:phosphorus ratios: 1150, 850 and 550). APA is a biomarker that is considered as a P deficiency indicator in zooplankton. Since recovery from UVR damage under dark conditions is an ATP depending reaction we also measured APA during recovery phases. We carried out a laboratory experiment combining different temperatures and food qualities with exposition to UVR followed by luminic and dark phases for recovery. In addition, we exposed organisms to H2O2, to establish if the response on APA to UVR was a consequence of the reactive oxygen species produced these short wavelengths. Our results showed that somatic APA was negatively affected by UVR exposure and this effect was enhanced under high temperature and low food quality. Consistently, GST activity was higher when exposed to UVR under both temperatures. The H2O2 experiments showed the same trend as UVR exposure, indicating that APA is affected mainly by oxidative stress than by direct effect of UVR on the enzyme. Finally, APA was affected in the dark phase of recovery confirming the P demands. These results enlighten the importance of food quality in the interacting effect of UVR and temperature, showing that C:P food ratio could determine the success or failure of zooplanktonic populations in a context of global change. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Alkaline Phosphatase Activity : an overlooked player on the phosphate behavior in macrotidal estuaries

    Science.gov (United States)

    Delmas, Daniel; Labry, Claire; Youenou, Agnes; Quere, Julien; Auguet, Jean Christophe; Montanie, Helene

    2014-05-01

    The non-conservative behavior of phosphate within the estuarine salinity gradient is essentially assigned to physico-chemical processes, such as desorption at low salinity and to benthic exchanges. Microbial phosphatase activity (APA), generally related to phosphate deficiency, is seldom studied in phosphate rich estuarine waters. In order to address the impact of microbial activity (bacterial abundance, production BSP, APA) on phosphate behavior, we studied these activities on a seasonal basis within the salinity gradient of two macrotidal estuaries presenting different levels of suspended solids. Whatever the season the Charente estuary is characterized by high levels of Suspended Particulate Matter (SPM > 1g.L-1), particularly in the Maximum Turbidity Zone (MTZ) located at the 5-10 psu. In this area characterized by high BSP and APA there is a significant increase of PO4 levels especially during summer. In the Aulne estuary the particle load is significantly lower (1/10) but high BSP and APA are equally recorded. In the highly turbid waters of the Charente estuary, active phytoplankton is virtually absent as pheopigments constitute up to 80% of the total pigments, particularly in the MTZ, therefore APA may essentially have a bacterial origin. In the Aulne estuary attached bacteria are dominant, both in numbers and production, and their distribution along the haline gradient perfectly follows those of APA and phosphate levels. These observations, associated with the very close relationships observed between APA, SPM and BSP, suggest that APA derive mainly from bacterial (attached) origin and operate at the expense of particulate phosphorus and hence contribute to PO4 regeneration, especially in spring and summer. Finally, as APA increased as PO4, whereas the reverse is observed in both fresh and marine waters, an original scheme for APA regulation, related to the large dominance of attached bacteria can be described for the estuarine waters.

  7. Study of possible changes brought about by plutonium oxide in the acid phosphatase activity of alveolar macrophages of the rabbit

    International Nuclear Information System (INIS)

    Rouvroy, Huguette

    1970-06-01

    This report describes the various techniques used for determining the acid phosphatase activity of alveolar rabbit macrophages after inhalation of radioactive plutonium oxide particles, exposure of the animals, removal and sampling of the alveolar cells, and technical dosage. The results obtained are presented; they do not make it possible, in this particular case, to affirm that an important change in the enzymatic activity studied occurs. (author) [fr

  8. Lowering of phytic acid content by enhancement of phytase and acid phosphatase activities during sunflower germination

    Directory of Open Access Journals (Sweden)

    Juliana da Silva Agostini

    2010-08-01

    Full Text Available The objective of this work was to investigate the germination of hybrid sunflowers BRS191 and C11 as a means of lowering phytic acid (PA content by enhancing the activity of endogenous phytase and acid phosphatase. The concentration of PA in hybrid sunflower achenes varied from 2.16 to 2.83g/100g of sample (p O objetivo deste trabalho foi investigar a germinação de girassóis híbridos BRS 191 e C11 com finalidade de reduzir o teor de AF e aumentar as atividades de phytases e fosfatases endógenas. A concentração do AF nos aquênios de girassóis híbridos variou de 2,16 a 2,83 g /100g de amostra (p< 0,005. As atividades de fitases e fosfatases de girassóis BRS191 e C11 foram elevadas no 4º e 5º dia de germinação, respectivamente, com liberação do fósforo necessário para o desenvolvimento da semente. Estes resultados indicam que o AF do girassol hibrido reduz e a atividade de phytase aumenta em períodos distintos da germinação, possibilitando assim a aplicação desta enzima no controle do teor de AF em cereais, melhorando o seu valor nutricional.

  9. Redox Modulation of PTEN Phosphatase Activity by Hydrogen Peroxide and Bisperoxidovanadium Complexes.

    Science.gov (United States)

    Lee, Chang-Uk; Hahne, Gernot; Hanske, Jonas; Bange, Tanja; Bier, David; Rademacher, Christoph; Hennig, Sven; Grossmann, Tom N

    2015-11-09

    PTEN is a dual-specificity protein tyrosine phosphatase. As one of the central tumor suppressors, a thorough regulation of its activity is essential for proper cellular homeostasis. The precise implications of PTEN inhibition by reactive oxygen species (e.g. H2 O2 ) and the subsequent structural consequences remain elusive. To study the effects of PTEN inhibition, bisperoxidovanadium (bpV) complexes serve as important tools with the potential for the treatment of nerve injury or cardiac ischemia. However, their mode of action is unknown, hampering further optimization and preventing therapeutic applications. Based on protein crystallography, mass spectrometry, and NMR spectroscopy, we elucidate the molecular basis of PTEN inhibition by H2O2 and bpV complexes. We show that both molecules inhibit PTEN via oxidative mechanisms resulting in the formation of the same intramolecular disulfide, therefore enabling the reactivation of PTEN under reductive conditions. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

  10. PME-1 protects ERK pathway activity from protein phosphatase 2A-mediated inactivation in human malignant glioma

    Science.gov (United States)

    Puustinen, Pietri; Junttila, Melissa R.; Vanhatupa, Sari; Sablina, Anna A.; Hector, Melissa E.; Teittinen, Kaisa; Raheem, Olayinka; Ketola, Kirsi; Lin, Shujun; Kast, Juergen; Haapasalo, Hannu; Hahn, William C.; Westermarck, Jukka

    2010-01-01

    ERK/MAPK pathway activity is regulated by the antagonist function of activating kinases and inactivating protein phosphatases. Sustained ERK pathway activity is commonly observed in human malignancies, however the mechanisms by which the pathway is protected from phosphatase-mediated inactivation in the tumor tissue remain obscure. Here we show that methylesterase PME-1-mediated inhibition of the protein phosphatase 2A (PP2A) promotes basal ERK pathway activity, and is required for efficient growth factor response. Mechanistically PME-1 is shown to support ERK pathway signaling upstream of Raf, but downstream of growth factor receptors and PKC. In malignant glioblastoma, PME-1 expression levels correlate with both ERK activity and cell proliferation in vivo. Moreover, PME-1 expression significantly correlates with disease progression in human astrocytic gliomas (N=222). Together, these observations identify PME-1 expression as one mechanism by which ERK pathway activity is maintained in cancer cells, and suggest important functional role for PME-1 in the disease progression of human astrocytic gliomas. PMID:19293187

  11. Facile colorimetric assay of alkaline phosphatase activity using Fe(II)-phenanthroline reporter.

    Science.gov (United States)

    Hu, Qiong; Zhou, Baojing; Dang, Pengyun; Li, Lianzhi; Kong, Jinming; Zhang, Xueji

    2017-01-15

    We report a versatile approach for the colorimetric assay of alkaline phosphatase (ALP) activity based on the distinctive metal-to-ligand charge-transfer (MLCT) absorption properties of Fe(II)-phenanthroline reporter. In the presence of ALP, the applied substrate ascorbic acid 2-phosphate is enzymatically hydrolyzed to produce ascorbic acid, which then reduces Fe 3+ to Fe 2+ . The complexation of Fe 2+ with the bathophenanthroline disulfonate (BPS) ligand generates a blood-red Fe(BPS) 3 4- reporter, which is characterized by an intense MLCT absorption band at 535 nm in the visible range. Under optimal conditions, the spectral output exhibits a good quantitative relationship with ALP activity over the range of 0-220 mU mL -1 with a detection limit of 0.94 mU mL -1 . Moreover, the activity of ALP can also be conveniently judged through naked-eye observations. Results indicate that it is highly selective and can be applied to the screening of ALP inhibitors. In addition, it has been successfully employed to detect the endogenous ALP level of undiluted human serum samples, with a detection limit of 1.05 mU mL -1 being achieved. This approach avoids any elaborately designed substrates and holds considerable simplicity and flexibility for reporter design. This study broadens the horizon of the applications of phenanthroline-based transition metal complexes. Furthermore, an efficient and practical method like this has the potential to be widely used in clinical applications and in the point-of-care testing. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Dissolved phosphorus pools and alkaline phosphatase activity in the euphotic zone of the western North Pacific Ocean.

    Directory of Open Access Journals (Sweden)

    Masahiro eSuzumura

    2012-03-01

    Full Text Available We measured pools of dissolved phosphorus (P, including dissolved inorganic P (DIP, dissolved organic P (DOP and alkaline phosphatase (AP-hydrolyzable labile DOP (L-DOP, and kinetic parameters of AP activity (APA in the euphotic zone in the western North Pacific Ocean. Samples were collected from one coastal station in Sagami Bay, Japan, and three offshore stations between the North Pacific Subtropical Gyre (NPSG and the Kuroshio region. Although DIP concentrations in the euphotic zone at all stations were equally low, around the nominal method detection limit of 20 nmol L−1, chlorophyll a (Chl a concentrations were one order of magnitude greater at the coastal station. DOP was the dominant P pool, comprising 62–92% of total dissolved P at and above the Chl a maximum layer (CML. L-DOP represented 22–39% of the total DOP at the offshore stations, whereas it accounted for a much higher proportion (about 85% in the coastal surface layers. Significant correlations between maximum potential AP hydrolysis rates and DIP concentrations or bacterial cell abundance in the offshore euphotic zone suggest that major APA in the oligotrophic surface ocean is from bacterial activity and regulated largely by DIP availability. Although the range of maximum potential APA was comparable among the environmental conditions, the in situ hydrolysis rate of L-DOP in the coastal station was 10 times those in the offshore stations. L-DOP turnover time at the CML ranged from 4.5 d at the coastal station to 84.4 d in the NPSG. The ratio of the APA half saturation constant to the ambient L-DOP concentration decreased markedly from the NPSG to the coastal station. There were substantial differences in the rate end efficiency of DOP remineralization and its contribution as the potential P source between the low-phosphate/high biomass coastal ecosystem and the low-phosphate/low biomass oligotrophic ocean.

  13. Influence of tebuconazole and copper hydroxide on phosphatase and urease activities in red sandy loam and black clay soils.

    Science.gov (United States)

    Anuradha, B; Rekhapadmini, A; Rangaswamy, V

    2016-06-01

    The efficacy of two selected fungicides i.e., tebuconazole and coppoer hydroxide, was conducted experiments in laboratory and copper hydroxide on the two specific enzymes phosphatase and urease were determined in two different soil samples (red sandy loam and black clay soils) of groundnut (Arachis hypogaea L.) from cultivated fields of Anantapuramu District, Andhra Pradesh. The activities of the selected soil enzymes were determined by incubating the selected fungicides-treated (1.0, 2.5, 5.0, 7.5 and 10.0 kg ha -1 ) and -untreated groundnut soil samples at 10 day intervals. By determining the effective concentration, the rate of selected enzyme activity was estimated by adding the suitable substrate at 10, 20, 30 and 40 days of soil incubation. Both the enzyme activities were increased up to 5.0 kg ha -1 level of fungicide in both soil samples significantly at 10 days of soil incubation and further enhanced up to 20 days of incubation. The activity of the phosphatase and urease decreased progressively at 30 and 40 days of incubation. From overall studies, higher concentrations (7.5 and 10.0 kg ha -1 ) of both tebuconazole and copper hydroxide were toxic to phosphatase and urease activities, respectively, in both soil samples.

  14. Amphoteric surface active agents

    OpenAIRE

    Eissa, A.M. F.

    1995-01-01

    2-[trimethyl ammonium, triethyl ammonium, pyridinium and 2-amino pyridinium] alkanoates, four series of surface active agents containing carbon chain C12, C14, C16 and C18carbon atoms, were prepared. Their structures were characterized by microanalysis, infrared (IR) and nuclear magnetic resonance (NMR). Surface and interfacial tension, Krafft point, wetting time, emulsification power, foaming height a...

  15. Luminal calcium concentration controls intestinal calcium absorption by modification of intestinal alkaline phosphatase activity.

    Science.gov (United States)

    Brun, Lucas R; Brance, María L; Rigalli, Alfredo

    2012-07-01

    Intestinal alkaline phosphatase (IAP) is a brush-border phosphomonoesterase. Its location suggests an involvement in the uptake of nutrients, but its role has not yet been defined. IAP expression parallels that of other proteins involved in Ca absorption under vitamin D stimulation. Experiments carried out in vitro with purified IAP have demonstrated an interaction between Ca and IAP. The gut is prepared to face different levels of Ca intake over time, but high Ca intake in a situation of a low-Ca diet over time would cause excessive entry of Ca into the enterocytes. The presence of a mechanism to block Ca entry and to avoid possible adverse effects is thus predictable. Thus, in the present study, Sprague-Dawley rats were fed with different amounts of Ca in the diet (0.2, 1 and 2 g%), and the percentage of Ca absorption (%Ca) in the presence and absence of L-phenylalanine (Phe) was calculated. The presence of Phe caused a significant increase in %Ca (52.3 (SEM 6.5) % in the presence of Phe v. 31.1 (sem 8.9) % in the absence of Phe, regardless of the amount of Ca intake; paired t test, P = 0.02). When data were analysed with respect to Ca intake, a significant difference was found only in the group with low Ca intake (paired t test, P = 0.03). Additionally, IAP activity increased significantly (ANOVA, P < 0.05) as Ca concentrations increased in the duodenal lumen. The present study provides in vivo evidence that luminal Ca concentration increases the activity of IAP and simultaneously decreases %Ca, acting as a minute-to-minute regulatory mechanism of Ca entry.

  16. Gingival crevicular fluid alkaline phosphatase activity in relation to pubertal growth spurt and dental maturation: A multiple regression study

    OpenAIRE

    Perinetti, G.; Contardo, L.

    2016-01-01

    Introduction: The identification of the onset of the pubertal growth spurt has major clinical implications when dealing with orthodontic treatment in growing subjects. Aim: Through multivariate methods, this study evaluated possible relationships between the gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity and pubertal growth spurt and dentition phase. Materials and methods: One hundred healthy growing subjects (62 females, 38 males; mean age, 11.5±2.4 years) were enr...

  17. A novel bifunctional hybrid with marine bacterium alkaline phosphatase and Far Eastern holothurian mannan-binding lectin activities.

    Directory of Open Access Journals (Sweden)

    Larissa Balabanova

    Full Text Available A fusion between the genes encoding the marine bacterium Cobetia marina alkaline phosphatase (CmAP and Far Eastern holothurian Apostichopus japonicus mannan-binding C-type lectin (MBL-AJ was performed. Expression of the fusion gene in E. coli cells resulted in yield of soluble recombinant chimeric protein CmAP/MBL-AJ with the high alkaline phosphatase activity and specificity of the lectin MBL-AJ. The bifunctional hybrid CmAP/MBL-AJ was produced as a dimer with the molecular mass of 200 kDa. The CmAP/MBL-AJ dimer model showed the two-subunit lectin part that is associated with two molecules of alkaline phosphatase functioning independently from each other. The highly active CmAP label genetically linked to MBL-AJ has advantaged the lectin-binding assay in its sensitivity and time. The double substitution A156N/F159K in the lectin domain of CmAP/MBL-AJ has enhanced its lectin activity by 25 ± 5%. The bifunctional hybrid holothurian's lectin could be promising tool for developing non-invasive methods for biological markers assessment, particularly for improving the MBL-AJ-based method for early detection of a malignant condition in cervical specimens.

  18. Alkaline phosphatase activity in the subtropical ocean: insights from nutrient, dust and trace metal addition experiments

    Directory of Open Access Journals (Sweden)

    Claire eMahaffey

    2014-12-01

    Full Text Available Phosphorus is an essential nutrient for all life on earth. In the ocean, the most bioavailable form of phosphorus is inorganic phosphate, but in the extensive subtropical gyres, phosphate concentrations can be chronically low and limit primary productivity and nitrogen fixation. In these regions, organisms produce hydrolytic enzymes, such as alkaline phosphatase (AP, that enable them to utilize the more replete dissolved organic phosphorus (DOP pool to meet their cellular phosphorus demands. In this study, we synthesized data from 14 published studies and present our own findings from two research cruises (D326 and D361 in the eastern subtropical Atlantic to explore the relationship between AP activity (APA and nutrients, Saharan dust and trace metals. We found that below a threshold phosphate concentration of ~ 30 nM, APA increased with an inverse hyperbolic relationship with phosphate concentration. Meanwhile, DOP concentrations decreased with enhanced APA, indicating utilization of the DOP pool. We found APA rates were significantly higher in the subtropical Atlantic compared to the subtropical Pacific Ocean, even over the same low phosphate concentration range (0 to 50 nM. While the phosphate concentration may have a first order control on the APA rates, we speculate that other factors influence this basin scale contrast. Using bioassay experiments, we show that the addition of Saharan dust and zinc significantly increased the rate of APA. To our knowledge, our results are the first direct field-based evidence that APA is limited by zinc in the subtropical ocean. Further work is required to explore the relationship between trace metals such as iron and zinc, which are co-factors of phosphohydrolytic enzymes, specifically PhoX and PhoA, respectively, and APA in the ocean.

  19. Acid phosphatase activity in the liver of Indian desert gerbil (Meriones hurrianae, Jerdon) exposed to internal β-irradiation

    International Nuclear Information System (INIS)

    Gupta, N.K.; Kumar, A.; Sharma, S.

    1985-01-01

    Alterations in acid phosphatase activity in the liver of Indian desert gerbil after administration of 45 Ca are reported. There is an increase in the enzyme activity during early periods after 45 Ca administration. The response of the enzyme to internal irradiation was dose dependent. The enzyme activity remained elevated for a longer period in animals given the higher dose. With starting repair, the activity declined and control values were nearly obtained on the 28 posttreatment day in gerbils having received 37 kBq/g body weight of 45 Ca. Animals with higher doses could not survive till this period

  20. Mild impairment of motor nerve repair in mice lacking PTP-BL tyrosine phosphatase activity.

    NARCIS (Netherlands)

    Wansink, D.G.; Peters, W.J.M; Schaafsma, I.; Sutmuller, R.P.M.; Oerlemans, F.T.J.J.; Adema, G.J.; Wieringa, B.; Zee, C.E.E.M. van der; Hendriks, W.J.A.J.

    2004-01-01

    Mouse PTP-BL is a large, nontransmembrane protein tyrosine phosphatase of unclear physiological function that consists of a KIND domain, a FERM domain, five PDZ domains, and a COOH-terminal catalytic PTP domain. PTP-BL and its human ortholog PTP-BAS have been proposed to play a role in the

  1. Fine-tuning of Pten localization and phosphatase activity is essential for zebrafish angiogenesis

    NARCIS (Netherlands)

    Stumpf, Miriam; Blokzijl-Franke, Sasja; Den Hertog, Jeroen

    2016-01-01

    The lipid- and protein phosphatase PTEN is an essential tumor suppressor that is highly conserved among all higher eukaryotes. As an antagonist of the PI3K/Akt cell survival and proliferation pathway, it exerts its most prominent function at the cell membrane, but (PIP3-independent) functions of

  2. Fine-Tuning of Pten Localization and Phosphatase Activity Is Essential for Zebrafish Angiogenesis

    NARCIS (Netherlands)

    Stumpf, Miriam; Blokzijl-Franke, Sasja; den Hertog, Jeroen

    2016-01-01

    The lipid- and protein phosphatase PTEN is an essential tumor suppressor that is highly conserved among all higher eukaryotes. As an antagonist of the PI3K/Akt cell survival and proliferation pathway, it exerts its most prominent function at the cell membrane, but (PIP3-independent) functions of

  3. Effecf of pH and some cations on activity of acid phosphatase secreted from Ustilago sp. isolated from acid sulphate soil

    Directory of Open Access Journals (Sweden)

    Chairatana Nilnond

    2007-03-01

    Full Text Available Acid phosphatase secreted from Ustilago sp. is able to hydrolyze organic phosphorus. These soil yeast microorganisms were isolated from rice roots grown in acid sulphate soil that generally contains highamount of aluminum (Al, iron (Fe and manganese (Mn ions. Therefore, the objectives of this study were to examine the effect of pH and some cations on acid phosphatase activity. Two isolates of Ustilago sp., AR101and AR102, were cultured in 100 mL of modified Pikovskaya's broth containing Na-phytate, pH 4, and acid phosphatase activity was determined at pH 2.0-7.0. Effect of Al, Fe, and Mn, including calcium (Ca ions,on growth of AR101 and AR102, secreted acid phosphatase activity, and the ability of acid phosphatase on the phosphorus release from Na-phytate by Ustilago sp. were investigated. It was found that the optimum pH for acid phosphatase activity was 3.5-4.5. The activity of acid phosphatase secreted from AR101 (3,690nmol min-1 mL-1 was remarkably higher than that from AR102 (956 nmol min-1 mL-1. Aluminum, iron, manganese and calcium ions in the medium did not affect the growth of either isolate. The activity of secretedacid phosphatase of AR101 was inhibited by Al and Ca ion, and synthesis of acid phosphatase of Ustilago sp. AR102 was possibly stimulated by Fe ion. Both AR101 and AR102 solubilized Na-phytate, resulting in therelease of P. However, some amount of released P was then precipitated with Al and Fe ions as the highly insoluble Fe- or Al- phosphate.

  4. Receptor protein tyrosine phosphatase alpha activates Src-family kinases and controls integrin-mediated responses in fibroblasts

    DEFF Research Database (Denmark)

    Su, J; Muranjan, M; Sap, J

    1999-01-01

    BACKGROUND: Fyn and c-Src are two of the most widely expressed Src-family kinases. Both are strongly implicated in the control of cytoskeletal organization and in the generation of integrin-dependent signalling responses in fibroblasts. These proteins are representative of a large family...... of tyrosine kinases, the activity of which is tightly controlled by inhibitory phosphorylation of a carboxyterminal tyrosine residue (Tyr527 in chicken c-Src); this phosphorylation induces the kinases to form an inactive conformation. Whereas the identity of such inhibitory Tyr527 kinases has been well...... established, no corresponding phosphatases have been identified that, under physiological conditions, function as positive regulators of c-Src and Fyn in fibroblasts. RESULTS: Receptor protein tyrosine phosphatase alpha (RPTPalpha) was inactivated by homologous recombination. Fibroblasts derived from...

  5. P depletion and activity of phosphatases in the rhizosphere of mycorrhizal and non-mycorrhizal cucumber (Cucumis Sativus L.)

    DEFF Research Database (Denmark)

    Joner, E.J.; Magid, J.; Gahoonia, T.S.

    1995-01-01

    fungi were grown in a sandy loam-sand mixture in three-compartment pots. Plant roots were separated from two consecutively adjoining compartments, first by a 37 m mesh excluding roots and subsequently by a 0.45 m membrane excluding mycorrhizal hyphae. Soil from the two root-free compartments......An experiment was set up to test the ability of arbuscular mycorrhizal (AM) roots and hyphae to produce extracellular phosphatases and to study the relationship between phosphatase activity and soil organic P (P-o). Non-mycorrhizal cucumber and cucumber in symbiosis with either of two mycorrhizal...... was sectioned in a freezing microtome and analyzed for extracellular acid (pH 5.2) and alkaline (pH 8.5) phosphatase activity as well as depletion of NaHCO-3-extractable inorganic P (P-i) and P-o. Roots and mycorrhizal hyphae depleted the soil of P-i but did not influence the concentration of P-o in spite...

  6. PME-1 modulates protein phosphatase 2A activity to promote the malignant phenotype of endometrial cancer cells.

    Science.gov (United States)

    Wandzioch, Ewa; Pusey, Michelle; Werda, Amy; Bail, Sophie; Bhaskar, Aishwarya; Nestor, Mariya; Yang, Jing-Jing; Rice, Lyndi M

    2014-08-15

    Protein phosphatase 2A (PP2A) negatively regulates tumorigenic signaling pathways, in part, by supporting the function of tumor suppressors like p53. The PP2A methylesterase PME-1 limits the activity of PP2A by demethylating its catalytic subunit. Here, we report the finding that PME-1 overexpression correlates with increased cell proliferation and invasive phenotypes in endometrial adenocarcinoma cells, where it helps maintain activated ERK and Akt by inhibiting PP2A. We obtained evidence that PME-1 could bind and regulate protein phosphatase 4 (PP4), a tumor-promoting protein, but not the related protein phosphatase 6 (PP6). When the PP2A, PP4, or PP6 catalytic subunits were overexpressed, inhibiting PME-1 was sufficient to limit cell proliferation. In clinical specimens of endometrial adenocarcinoma, PME-1 levels were increased and we found that PME-1 overexpression was sufficient to drive tumor growth in a xenograft model of the disease. Our findings identify PME-1 as a modifier of malignant development and suggest its candidacy as a diagnostic marker and as a therapeutic target in endometrial cancer. ©2014 American Association for Cancer Research.

  7. Valproic acid induces hair regeneration in murine model and activates alkaline phosphatase activity in human dermal papilla cells.

    Directory of Open Access Journals (Sweden)

    Soung-Hoon Lee

    Full Text Available Alopecia is the common hair loss problem that can affect many people. However, current therapies for treatment of alopecia are limited by low efficacy and potentially undesirable side effects. We have identified a new function for valproic acid (VPA, a GSK3β inhibitor that activates the Wnt/β-catenin pathway, to promote hair re-growth in vitro and in vivo.Topical application of VPA to male C3H mice critically stimulated hair re-growth and induced terminally differentiated epidermal markers such as filaggrin and loricrin, and the dermal papilla marker alkaline phosphatase (ALP. VPA induced ALP in human dermal papilla cells by up-regulating the Wnt/β-catenin pathway, whereas minoxidil (MNX, a drug commonly used to treat alopecia, did not significantly affect the Wnt/β-catenin pathway. VPA analogs and other GSK3β inhibitors that activate the Wnt/β-catenin pathway such as 4-phenyl butyric acid, LiCl, and BeCl(2 also exhibited hair growth-promoting activities in vivo. Importantly, VPA, but not MNX, successfully stimulate hair growth in the wounds of C3H mice.Our findings indicate that small molecules that activate the Wnt/β-catenin pathway, such as VPA, can potentially be developed as drugs to stimulate hair re-growth.

  8. 3D restoration microscopy improves quantification of enzyme-labeled fluorescence-based single-cell phosphatase activity in plankton. Cytometry Part A, 85A: 841–853

    Czech Academy of Sciences Publication Activity Database

    Diaz-de-Quijano, D.; Palacios, P.; Horňák, Karel; Felip, M.

    85A, č. 10 (2014), s. 841-853 ISSN 1552-4922 Institutional support: RVO:60077344 Keywords : 3D fluorescence microscopy * deconvolution * ELF phosphate * phosphatase activity * phytoplankton Subject RIV: EE - Microbiology, Virology Impact factor: 2.928, year: 2014

  9. Amphoteric surface active agents

    Directory of Open Access Journals (Sweden)

    Eissa, A.M. F.

    1995-10-01

    Full Text Available 2-[trimethyl ammonium, triethyl ammonium, pyridinium and 2-amino pyridinium] alkanoates, four series of surface active agents containing carbon chain C12, C14, C16 and C18carbon atoms, were prepared. Their structures were characterized by microanalysis, infrared (IR and nuclear magnetic resonance (NMR. Surface and interfacial tension, Krafft point, wetting time, emulsification power, foaming height and critical micelle concentration (cmc were determined and a comparative study was made between their chemical structure and surface active properties. Antimicrobial activity of these surfactants was also determined.

    Se prepararon cuatro series de agentes tensioactivos del tipo 2-[trimetil amonio, trietil amonio, piridinio y 2-amino piridinio] alcanoatos, que contienen cadenas carbonadas con C12, C14, C16 y C18 átomos de carbono.
    Se determinaron la tensión superficial e interfacial, el punto de Krafft, el tiempo humectante, el poder de emulsionamiento, la altura espumante y la concentración critica de miscela (cmc y se hizo un estudio comparativo entre la estructura química y sus propiedades tensioactivas. Se determinó también la actividad antimicrobiana de estos tensioactivos. Estas estructuras se caracterizaron por microanálisis, infrarrojo (IR y resonancia magnética nuclear (RMN.

  10. VPS29 is not an active metallo-phosphatase but is a rigid scaffold required for retromer interaction with accessory proteins.

    Directory of Open Access Journals (Sweden)

    James D Swarbrick

    Full Text Available VPS29 is a key component of the cargo-binding core complex of retromer, a protein assembly with diverse roles in transport of receptors within the endosomal system. VPS29 has a fold related to metal-binding phosphatases and mediates interactions between retromer and other regulatory proteins. In this study we examine the functional interactions of mammalian VPS29, using X-ray crystallography and NMR spectroscopy. We find that although VPS29 can coordinate metal ions Mn(2+ and Zn(2+ in both the putative active site and at other locations, the affinity for metals is low, and lack of activity in phosphatase assays using a putative peptide substrate support the conclusion that VPS29 is not a functional metalloenzyme. There is evidence that structural elements of VPS29 critical for binding the retromer subunit VPS35 may undergo both metal-dependent and independent conformational changes regulating complex formation, however studies using ITC and NMR residual dipolar coupling (RDC measurements show that this is not the case. Finally, NMR chemical shift mapping indicates that VPS29 is able to associate with SNX1 via a conserved hydrophobic surface, but with a low affinity that suggests additional interactions will be required to stabilise the complex in vivo. Our conclusion is that VPS29 is a metal ion-independent, rigid scaffolding domain, which is essential but not sufficient for incorporation of retromer into functional endosomal transport assemblies.

  11. Low Soil Phosphorus Availability Increases Acid Phosphatases Activities and Affects P Partitioning in Nodules, Seeds and Rhizosphere of Phaseolus vulgaris

    Directory of Open Access Journals (Sweden)

    Jean-Jacques Drevon

    2012-06-01

    Full Text Available The effect of phosphorus (P deficiency on phosphatases activities in N2-fixing legumes has been widely studied in hydroponic culture. However, the response of acid phosphatase (APase and phytase in rhizosphere, nodules and seeds of Phaseolus vulgaris to low soil’s P-availability is not yet fully understood. In this study, six genotypes of N2-fixing P. vulgaris were grown under contrasting soil P-availabilities; i.e., low  (4.3 mg P kg−1 and sufficient (16.7 mg P kg−1 in the Haouz region of Morocco. At flowering and maturity stages, plants were harvested and analyzed for their phosphatases activities, growth and P content. Results show that, low P decreased nodulation, growth, P uptake and N accumulation in all the genotypes, but to a greater extent in the sensitive recombinant inbreed line 147. In addition, while seed P content was slightly reduced under low P soil; a higher P was noticed in the Flamingo and Contender large seeded-beans (6.15 to 7.11 mg g−1. In these latter genotypes, high APase and phytase activities in seeds and nodules were associated with a significant decline in rhizosphere’s available P. APase activity was mainly stimulated in nodules, whereas phytase activity was highly induced in seeds (77%. In conclusion, the variations of APase and phytase activities in nodules and seeds depend on genotype and can greatly influence the internal utilization of P, which might result in low P soil tolerance in N2-fixing legumes.

  12. Cell-specific extracellular phosphatase activity of dinoflagellate populations in acidified mountain lakes

    Czech Academy of Sciences Publication Activity Database

    Novotná, J.; Nedbalová, Linda; Kopáček, Jiří; Vrba, Jaroslav

    2010-01-01

    Roč. 46, č. 4 (2010), s. 635-644 ISSN 0022-3646 R&D Projects: GA AV ČR IAA600170602; GA ČR GA206/07/1200 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z60170517 Keywords : extracellular phosphatases * acidified lakes * dinoflagellates Subject RIV: EF - Botanics Impact factor: 2.239, year: 2010

  13. Alkaline Phosphatase Activity in Seawater: Influence of Reaction Conditions on the Kinetic Parameters of ALP

    OpenAIRE

    Orhanović, Stjepan; Pavela-Vrančič, Maja

    2000-01-01

    Alkaline phosphatase (ALP) is an extracellular enzyme enabling utilisation of phosphomonoesters as the source of inorganic phosphate (Pi) required for the maintenance of cellular metabolism. Its catalytic properties have been extensively studied in aquatic environments in an attempt to describe its influence on phosphorous cycling in natural waters. Despite its significance and frequent determination, no standard method has been developed so far. In order to examine the effect of various reac...

  14. The effect of water and salt stresses on the phosphorus content and acid phosphatase activity in oilseed rape

    Directory of Open Access Journals (Sweden)

    Stanisław Flasiński

    2014-01-01

    Full Text Available Oilseed rape plants responded to water and salt stresses (-0.5 MPa, PEG 6000 and NaCI by reduction of the fresh and dry weights of shoots and roots. When PEG was used, the ratio of dry weights of roots:shoots surpassed that of controls. The leaf protein content increased considerably. The phosphorus content decreased only in the roots, most significantly after three days of stress. Immediately after the stresses were induced, an increase in the acid phosphatase (AP activity was noted. Water and salt stresses caused four- and two-fold increases in AP activity in leaves, respectively. Changes in the enzyme activity were negligible in stems and roots. There are nine forms of AP in young leaves of oilseed rape. In the stressed plants, from No. 5 revealed lower activity and forms Nos 8 and 9, higher activities than in the control. The increase in AP activity was directly accompanied by the decrease in the water potential of the tissues. Oilseed rape is considerably less sensitive to salt stress than to water stress, which is manifested as the lower inhibition of plant growth and also by a smaller increase in acid phosphatase activity.

  15. Exchange potentials of phosphorus between sediments and water coupled to alkaline phosphatase activity and environmental factors in an oligo-mesotrophic reservoir.

    Science.gov (United States)

    Mhamdi, Badre Alaoui; Azzouzi, Assia; Elloumi, Jannet; Ayadi, Habib; Mhamdi, Mohammed Alaoui; Aleya, Lotfi

    2007-05-01

    We investigated the exchange potentials of phosphates at the water-sediment interface together with in situ benthic-chamber fractionated alkaline phosphatase activity and bacteria estimates during September and October 1998 at two stations: station 1, which received immediately the urban inputs from the Taounate city, and station 2, located in the centre of the Sahela reservoir (Morocco). The results showed that low oxygenation enhanced both the bacterial abundance and the alkaline phosphatase activity. Size-fractionated (0.65-100 microm) bacteria attached to dead organic matter together with algae and zooplankton contributed strongly (78%) to the total alkaline phosphatase synthesis in the two sampled stations, suggesting that attachment to organic particles stimulated phosphatase activities. The appearance of anoxic conditions and the decrease of pH supported the dissolution of particulate phosphorus and the release of soluble reactive phosphorus. This latter, together with persisting discharges of organic matter, sewage, and olive mill waste will exacerbate the eutrophication of the reservoir.

  16. Co-ordinate regulation of growth factor receptors and lipid phosphate phosphatase-1 controls cell activation by exogenous lysophosphatidate.

    Science.gov (United States)

    Pilquil, C; Ling, Z C; Singh, I; Buri, K; Zhang, Q X; Brindley, D N

    2001-11-01

    The serum-derived lipid growth factors, lysophosphatidate (LPA) and sphingosine 1-phosphate (S1P), activate cells selectively through different members of a family of endothelial differentiation gene (EDG) receptors. Activation of EDG receptors by LPA and S1P provides a variety of signalling cascades depending upon the G-protein coupling of the different EDG receptors. This leads to chemotactic and mitogenic responses, which are important in wound healing. For example, LPA stimulates fibroblast division and S1P stimulates the chemotaxis and division of endothelial cells leading to angiogenesis. Counteracting these effects of LPA and S1P, are the actions of lipid phosphate phosphatases (LPP, or phosphatidate phosphohydrolases, Type 2). The isoform LPP-1 is expressed in the plasma membrane with its active site outside the cell. This enzyme is responsible for 'ecto-phosphatase' activity leading to the degradation of exogenous lipid phosphate mediators, particularly LPA. Expression of LPP-1 decreases cell activation by exogenous LPA. The mechanism for this is controversial and several mechanisms have been proposed. Evidence will be presented that the LPPs cross-talk with EDG and other growth factor receptors, thus, regulating the responses of the cells to lipid phosphate mediators of signal transduction.

  17. Phosphorus content and distribution and the activity of phosphatases in Arenosols in a forest affected by long-term exposure to the effects of the Anwil S.A. nitrogen works in Włocławek

    Directory of Open Access Journals (Sweden)

    Lemanowicz Joanna

    2015-09-01

    Full Text Available This paper presents the results of research examining the soil content of total and available phosphorus (PE-R, taking into consideration the activity of alkaline and acid phosphatases. For this study, three soil profiles were sampled in Arenosols at a distance of 0.8, 2.0 and 2.5 km from a nitrogen fertiliser manufacturer, Anwil S.A. A control profile was taken from the Tuchola Forest. The soils’ reaction ranged from acidic to very acidic. The humus content in the surface horizons of the sampled profiles was average (1.26–2.61%. The lowest PE-R content was found in the profile taken closest (0.8 km – profile I to the factory. The distribution index (DI calculated for available phosphorus pointed towards moderate accumulation, whilst at the same time, the availability index (IM confirmed low availability, especially in profile I. The activity of alkaline and acid phosphatases, which are the enzymes responsible for phosphorus transformation in the soil, varied depending on the distance from the nitrogen works. The inhibition of alkaline phosphomonoesterases and the stimulation of acid esterases, which were both connected to the examined soil reaction, were observed. The activity of phosphatases, as well as total and available phosphorus content, decreased steeply along the soil profiles. Furthermore, a significant correlation between organic carbon and the activity of alkaline and acid phosphatases (r = 0.94, p < 0.05 and r = 0.67, p < 0.05, respectively, as well as between the content of PE-R and the activity of alkaline phosphatase (r = 0.67, p < 0.05 were recorded. The results suggest the need for further research and monitoring of the Arenosols in the forest affected by the nitrogen works.

  18. Phosphate solubilization and acid phosphatase activity of Serratia sp. isolated from mangrove soil of Mahanadi river delta, Odisha, India

    Directory of Open Access Journals (Sweden)

    B.C. Behera

    2017-06-01

    Full Text Available Phosphorus is an essential element for all life forms. Phosphate solubilizing bacteria are capable of converting phosphate into a bioavailable form through solubilization and mineralization processes. Hence in the present study a phosphate solubilizing bacterium, PSB-37, was isolated from mangrove soil of the Mahanadi river delta using NBRIP-agar and NBRIP-BPB broth containing tricalcium phosphate as the phosphate source. Based on phenotypic and molecular characterization, the strain was identified as Serratia sp. The maximum phosphate solubilizing activity of the strain was determined to be 44.84 μg/ml, accompanied by a decrease in pH of the growth medium from 7.0 to 3.15. During phosphate solubilization, various organic acids, such as malic acid (237 mg/l, lactic acid (599.5 mg/l and acetic acid (5.0 mg/l were also detected in the broth culture through HPLC analysis. Acid phosphatase activity was determined by performing p-nitrophenyl phosphate assay (pNPP of the bacterial broth culture. Optimum acid phosphatase activity was observed at 48 h of incubation (76.808 U/ml, temperature of 45 °C (77.87 U/ml, an agitation rate of 100 rpm (80.40 U/ml, pH 5.0 (80.66 U/ml and with glucose as a original carbon source (80.6 U/ml and ammonium sulphate as a original nitrogen source (80.92 U/ml. Characterization of the partially purified acid phosphatase showed maximum activity at pH 5.0 (85.6 U/ml, temperature of 45 °C (97.87 U/ml and substrate concentration of 2.5 mg/ml (92.7 U/ml. Hence the present phosphate solubilizing and acid phosphatase production activity of the bacterium may have probable use for future industrial, agricultural and biotechnological application.

  19. Toxic impact of aldrin on acid and alkaline phosphatase activity of penaeid prawn, Metapenaeus monoceros: In vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, M.S.; Jayaprada, P.; Rao, K.V.R. (Sri Venkateswara Univ. Post Graduate Center, Kavali (India))

    1991-03-01

    The increasing contamination of the aquatic environment by the indiscriminate and widespread use of different kinds of pesticides is a serious problem for environmental biologists. Organochlorine insecticides are more hazardous since they are not only more toxic but also leave residues in nature. The deleterious effects of aldrin on several crustaceans have been studied. But studies concerning the impact of aldrin on biochemical aspects of crustaceans are very much limited. The present study is aimed at probing the in vitro effects of aldrin on the acid and alkaline phosphatase activity levels in selected tissues of penaeid prawn, Metapenaeus monoceros (Fabricius).

  20. Antidepressant Activity of Enicostemma littorale Blume in Shp2 (Protein Tyrosine Phosphatase)-inhibited Animal Model of Depression

    OpenAIRE

    Doss, VA; Kuberapandian, Dharaniyambigai

    2016-01-01

    Background: The objective of this study is to develop a new animal model based on signaling pathways to understand the pathophysiology, therapy of depression, and to investigate the antidepressant activity of Enicostemma littorale which is not yet established. Methods: Animal models of depression were raised by physical methods and administration of methyl isobutyl ketone (100 mg/kg b.w., i.p.,) and a protein tyrosine phosphatase inhibitor, sodium orthovanadate (30 mg/kg b.w., i.p.,) to y...

  1. TAMRA/TAMRA Fluorescence Quenching Systems for the Activity Assay of Alkaline Phosphatase

    OpenAIRE

    Shiba, Akio; Kinoshita-Kikuta, Emiko; Kinoshita, Eiji; Koike, Tohru

    2017-01-01

    We introduce two types of fluorescence-quenching assay for alkaline phosphatases (APs) by using a carboxytetramethyl-rhodamine (TAMRA)-labeled phosphate-binding tag molecule (TAMRA-Phos-tag). In the first assay, TAMRA-labeled O-phosphorylethanolamine (TAMRA-PEA) was used as an artificial AP-substrate. TAMRA-Phos-tag specifically captured TAMRA-PEA to form a 1:1 complex at pH 7.4; the intensity of the fluorescence peak of the complex at 580 nm (?ex = 523 nm) was significantly reduced to 32% of...

  2. Effects of LAR and PTP-BL phosphatase deficiency on adult mouse retinal cells activated by lens injury.

    NARCIS (Netherlands)

    Lorber, B.; Hendriks, W.J.A.J.; Zee, C.E.E.M. van der; Berry, M.; Logan, A.

    2005-01-01

    Using intact and lens-lesioned wildtype, leucocyte common antigen-related phosphatase deficient (LARDeltaP) and protein tyrosine phosphatase (PTP)-BAS-like phosphatase deficient (PTP-BLDeltaP) mice, we have evaluated the role of LAR and PTP-BL in retinal ganglion cell survival and neuritogenesis,

  3. A method for analysing phosphatase activity in aquatic bacteria at the single cell level using flow cytometry.

    Science.gov (United States)

    Duhamel, Solange; Gregori, Gerald; Van Wambeke, France; Mauriac, Romain; Nedoma, Jirí

    2008-10-01

    It has been demonstrated that ELF97-phosphate (ELF-P) is a useful tool to detect and quantify phosphatase activity of phytoplankton populations at a single cell level. Recently, it has been successfully applied to marine heterotrophic bacteria in culture samples, the cells exhibiting phosphatase activity being detected using epifluorescence microscopy. Here, we describe a new protocol that enables the detection of ELF alcohol (ELFA), the product of ELF-P hydrolysis, allowing the detection of phosphatase positive bacteria, using flow cytometry. Bacteria from natural samples must be disaggregated and, in oligotrophic waters, concentrated before they can be analyzed by flow cytometry. The best efficiency for disaggregating/separating bacterial cell clumps was obtained by incubating the sample for 30 min with Tween 80 (10 mg l(-1), final concentration). A centrifugation step (20,000 g; 30 min) was required in order to recover all the cells in the pellet (only 7+/-2% of the cells were recovered from the supernatant). The cells and the ELFA precipitates were resistant to these treatments. ELFA-labelled samples were stored in liquid nitrogen for up to four months before counting without any significant loss in total or ELFA-labelled bacterial cell abundance or in the ELFA fluorescence intensity. We describe a new flow cytometry protocol for detecting and discriminating the signals from both ELFA and different counterstains (4',6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI)) necessary to distinguish between ELFA-labelled and non ELFA-labelled heterotrophic bacteria. The method has been successfully applied in both freshwater and marine samples. This method promises to improve our understanding of the physiological response of heterotrophic bacteria to P limitation.

  4. 2-Substituted 7-trifluoromethyl-thiadiazolopyrimidones as alkaline phosphatase inhibitors. Synthesis, structure activity relationship and molecular docking study.

    Science.gov (United States)

    Jafari, Behzad; Ospanov, Meirambek; Ejaz, Syeda Abida; Yelibayeva, Nazym; Khan, Shafi Ullah; Amjad, Sayyeda Tayyeba; Safarov, Sayfidin; Abilov, Zharylkasyn A; Turmukhanova, Mirgul Zh; Kalugin, Sergey N; Ehlers, Peter; Lecka, Joanna; Sévigny, Jean; Iqbal, Jamshed; Langer, Peter

    2018-01-20

    Alkaline Phosphatases (APs) play a key role in maintaining a ratio of phosphate to inorganic pyrophosphate (P i /PP i ) and thus regulate extracellular matrix calcification during bone formation and growth. Among different isozymes of AP, aberrant increase in the level of tissue non-specific alkaline phosphatase (TNAP) is strongly associated with vascular calcification and end-stage renal diseases. In this context, we synthesized a novel series of fluorinated pyrimidone derivatives, i.e., 2-bromo-7-trifluoromethyl-5-oxo-5H-1,3,4-thiadiazolepyrimidones. The bromine functionality was further used for derivatisation by nucleophilic aromatic substitution using amines as nucleophiles as well as by Palladium catalysed Suzuki-Miyaura reactions. The synthesized derivatives were found potent but non-selective inhibitors of both isozymes of AP. Arylated thiadiazolopyrimidones exhibited stronger inhibitory activities than 2-amino-thiadiazolopyrimidones. The binding modes and possible interactions of the most active inhibitor within the active site of the enzyme were observed by molecular docking studies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Seasonal phosphatase activity in three characteristic soils of the English uplands polluted by long-term atmospheric nitrogen deposition

    International Nuclear Information System (INIS)

    Turner, B.L.; Baxter, Robert; Whitton, B.A.

    2002-01-01

    High soil phosphatase activities confirm strong biological phosphorus limitations due to nitrogen deposition. - Phosphomonoesterase activities were determined monthly during a seasonal cycle in three characteristic soil types of the English uplands that have been subject to long-term atmospheric nitrogen deposition. Activities (μmol para-nitrophenol g -1 soil dry wt. h -1 ) ranged between 83.9 and 307 in a blanket peat (total carbon 318 mg g -1 , pH 3.9), 45.2-86.4 in an acid organic grassland soil (total carbon 354 mg g -1 , pH 3.7) and 10.4-21.1 in a calcareous grassland soil (total carbon 140 mg g -1 , pH 7.3). These are amongst the highest reported soil phosphomonoesterase activities and confirm the strong biological phosphorus limitation in this environment

  6. Low dietary copper increases fecal free radical production, fecal water alkaline phosphatase activity and cytotoxicity in healthy men.

    Science.gov (United States)

    Davis, Cindy D

    2003-02-01

    One possible dietary factor that may increase susceptibility to colon cancer is inadequate copper intake. The objective of this study was to investigate the effects of low and adequate copper intakes on copper nutriture and putative risk factors for colon cancer susceptibility in healthy men. Seventeen healthy free-living nonsmoking men aged 21-52 y completed a 13-wk controlled feeding study in a randomized crossover design. The basal diet contained 0.59 mg Cu/13.65 MJ. After a 1-wk equilibration period in which the men consumed the basal diet supplemented with 1.0 mg Cu/d, they were randomly assigned to receive either the basal diet or the basal diet supplemented with 2 mg Cu/d for 6 wk. After the first dietary period, the men immediately began to consume the other level of Cu for the last 6 wk. They collected their feces during the equilibration period and during the last 2 wk of the two dietary periods for free radical and fecal water analysis. Low dietary copper significantly (P alkaline phosphatase activity. Low dietary copper significantly (P dietary treatments. These results suggest that low dietary copper adversely affects fecal free radical production and fecal water alkaline phosphatase activity, which are putative risk factors for colon cancer.

  7. Chemical redox modulated fluorescence of nitrogen-doped graphene quantum dots for probing the activity of alkaline phosphatase.

    Science.gov (United States)

    Liu, JingJing; Tang, Duosi; Chen, Zhitao; Yan, Xiaomei; Zhong, Zhou; Kang, Longtian; Yao, Jiannian

    2017-08-15

    Alkaline phosphatase (ALP) as an essential enzyme plays an important role in clinical diagnoses and biomedical researches. Hence, the development of convenient and sensitivity assay for monitoring ALP is extremely important. In this work, on the basis of chemical redox strategy to modulate the fluorescence of nitrogen-doped graphene quantum dots (NGQDs), a novel label-free fluorescent sensing system for the detection of alkaline phosphatase (ALP) activity has been developed. The fluorescence of NGQDs is firstly quenched by ultrathin cobalt oxyhydroxide (CoOOH) nanosheets, and then restored by ascorbic acid (AA), which can reduce CoOOH to Co 2+ , thus the ALP can be monitored based on the enzymatic hydrolysis of L-ascorbic acid-2-phosphate (AAP) by ALP to generate AA. Quantitative evaluation of ALP activity in a range from 0.1 to 5U/L with the detection limit of 0.07U/L can be realized in this sensing system. Endowed with high sensitivity and selectivity, the proposed assay is capable of detecting ALP in biological system with satisfactory results. Meanwhile, this sensing system can be easily extended to the detection of various AA-involved analytes. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Variations of alkaline phosphatase activity and P fractions in sediments of a shallow Chinese eutrophic lake (Lake Taihu)

    International Nuclear Information System (INIS)

    Zhang Tingxi; Wang Xiaorong; Jin Xiangcan

    2007-01-01

    The distribution of alkaline phosphatase activity (APA) and P fractions in sediment cores and the relationship between them were studied in a shallow Chinese freshwater lake (Lake Taihu). Sediment cores were collected from four sites, characterized by different degrees of eutrophication in June 2004. Sediment P was fractionated into Fe/Al-P, Ca-P, organic P (OP), inorganic P (IP) and total P (TP). The former two species made the largest contribution to the sediment P pool. Results show that trophic status and hydrological conditions have great impact on the APA of the sediments. The order of the APA in sediments was conjectured to be: macrophyte dominated lake > transitional lake > algal dominated lake. APA profiles follow a similar downcore decreasing trend. There was a positive relationship between the APA and the TP, IP. The multiple linear regression equation of the APA and P fractions is: APA = -97 + 0.768TP - 0.985Fe/Al-P. - Characteristics of the alkaline phosphatase activity and P fractions in sediments of different trophic status lake were studied in Lake Taihu

  9. Amino acid sequence of the cold-active alkaline phosphatase from Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Asgeirsson, Bjarni; Nielsen, Berit Noesgaard; Højrup, Peter

    2003-01-01

    Atlantic cod is a marine fish that lives at low temperatures of 0-10 degrees C and contains a cold-adapted alkaline phosphatase (AP). Preparations of AP from either the lower part of the intestines or the pyloric caeca area were subjected to proteolytic digestion, mass spectrometry and amino acid...... has the same variable residues as mammalian APs (His153 and His328 by E. coli AP numbering). General comparison of the amino acid composition with mammalian APs showed that cod AP contains fewer Cys, Leu, Met and Ser, but proportionally more Asn, Asp, Ile, Lys, Trp and Tyr residues. Three N......-linked glycosylation sites were found. The glycan structure was determined as complex biantennary in type with fucose and sialic acid attached, although a trace of complex tri-antennary structure was also observed. A three-dimensional model was obtained by homology modelling using the human placental AP scaffold. Cod...

  10. Protein phosphatase 2Cδ/Wip1 regulates phospho-p90RSK2 activity in lesional psoriatic skin

    Directory of Open Access Journals (Sweden)

    Rasmussen MK

    2017-12-01

    Full Text Available Mads K Rasmussen, Jakob Nielsen, Rasmus B Kjellerup, Stine M Andersen, Anne H Rittig, Claus Johansen, Lars Iversen, Borbala Gesser Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark Objectives: P90 ribosomal S6 kinase (RSK 1 and 2 are serine/threonine protein kinases believed to mediate proliferation and apoptosis via the extracellular signal-regulated kinases (ERK1/2 signaling pathway. Macrophage migration inhibitory factor (MIF and epidermal growth factor (EGF are activators of this pathway and are elevated in the serum of patients with psoriasis compared with healthy controls. Studies on COS-7 cell cultures have shown that protein phosphatase 2Cδ (PP2Cδ decreases the activity of RSK2 following EGF stimulation. We therefore hypothesize that PP2Cδ regulates RSK2 activity in psoriasis. Methods: In paired biopsies from nonlesional (NL and lesional (L skins, we analyzed the level of RSK1, 2 phosphorylation and the expression of PP2Cδ isoforms, integrin-linked kinase-associated serine/threonine phosphatase (ILKAP and wild-type p53-induced phosphatase 1 (Wip1 by Western blotting, immunofluorescence and coimmunoprecipitation with monoclonal antibody for RSK2. The induction of Wip1 by MIF or EGF was studied in cultured normal human keratinocytes.Results: The protein level of RSK1, 2 phosphorylated at T573/T577 was significantly increased in L compared with NL psoriatic skin, while phosphorylation at S380/S386 was reduced in L compared with NL psoriatic skin when assayed by Western blotting and immunofluorescence microscopy. ILKAP expression was significantly higher in L than in NL skin, whereas Wip1 was expressed in similar amounts but showed increased coimmunoprecipitation with RSK2 in L compared with NL psoriatic skin. In cultured normal human keratinocytes stimulated with MIF, Wip1 phosphorylation and Wip1 expression were increased after 24 hours, but not when costimulated with dimethyl fumarate (DMF. The increased

  11. cAMP response element binding protein (CREB activates transcription via two distinct genetic elements of the human glucose-6-phosphatase gene

    Directory of Open Access Journals (Sweden)

    Stefano Luisa

    2005-01-01

    Full Text Available Abstract Background The enzyme glucose-6-phosphatase catalyzes the dephosphorylation of glucose-6-phosphatase to glucose, the final step in the gluconeogenic and glycogenolytic pathways. Expression of the glucose-6-phosphatase gene is induced by glucocorticoids and elevated levels of intracellular cAMP. The effect of cAMP in regulating glucose-6-phosphatase gene transcription was corroborated by the identification of two genetic motifs CRE1 and CRE2 in the human and murine glucose-6-phosphatase gene promoter that resemble cAMP response elements (CRE. Results The cAMP response element is a point of convergence for many extracellular and intracellular signals, including cAMP, calcium, and neurotrophins. The major CRE binding protein CREB, a member of the basic region leucine zipper (bZIP family of transcription factors, requires phosphorylation to become a biologically active transcriptional activator. Since unphosphorylated CREB is transcriptionally silent simple overexpression studies cannot be performed to test the biological role of CRE-like sequences of the glucose-6-phosphatase gene. The use of a constitutively active CREB2/CREB fusion protein allowed us to uncouple the investigation of target genes of CREB from the variety of signaling pathways that lead to an activation of CREB. Here, we show that this constitutively active CREB2/CREB fusion protein strikingly enhanced reporter gene transcription mediated by either CRE1 or CRE2 derived from the glucose-6-phosphatase gene. Likewise, reporter gene transcription was enhanced following expression of the catalytic subunit of cAMP-dependent protein kinase (PKA in the nucleus of transfected cells. In contrast, activating transcription factor 2 (ATF2, known to compete with CREB for binding to the canonical CRE sequence 5'-TGACGTCA-3', did not transactivate reporter genes containing CRE1, CRE2, or both CREs derived from the glucose-6-phosphatase gene. Conclusions Using a constitutively active CREB2

  12. Maltol complexes of vanadium (IV) and (V) regulate in vitro alkaline phosphatase activity and osteoblast-like cell growth.

    Science.gov (United States)

    Barrio, D A; Braziunas, M D; Etcheverry, S B; Cortizo, A M

    1997-06-01

    Vanadium compounds have been found to possess insulin- and growth factor-mimetic effects. In consequence, these derivatives are potentially useful as effective oral therapeutic agents in diabetic patients. However, their use has been limited by various toxic side-effects and by the low solubility of different derivatives. Recently, vanadium complex with maltol, a sugar used as a common food additive, have been synthesised and investigated in animals, showing possible insulin-mimetic effects with low toxic side-effects. In the present study we have investigated the effect of bis(maltolato)oxovanadium (IV) (BMOV) and bis(maltolato)dioxovanadium (V) (BMV) on bone cells in culture as well as their direct effect on alkaline phosphatase in vitro. A comparison was also made with the action of vanadate and vanadyl cation. Vanadium compounds regulated cell proliferation in a biphasic manner with similar potencies. Osteoblast differentiation, assessed by alkaline phosphatase activity, was found to be dose-dependent, with the inhibitory effect being stronger for vanadate and BMOV than for vanadyl and BMV. All vanadium compounds directly inhibited bovine intestinal ALP with a similar potency. Thus, maltol vanadium derivatives behave in a similar way to vanadate and vanadyl in osteoblast-like UMR 106 cells in culture.

  13. Maltol complexes of vanadium (IV) and (V) regulate in vitro alkaline phosphatase activity and osteoblast-like cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, D.A.; Braziunas, M.D. [Catedra de Bioquimica Patologica, Universidad Nacional de la Plata (Argentina); Etcheverry, S.B. [Catedra de Bioquimica Patologica, Universidad Nacional de la Plata (Argentina)]|[CEQUINOR, Facultad de Ciencias Exactas, Universidad Nacional de la Plata (Argentina); Cortizo, A.M. [CEQUINOR, Facultad de Ciencias Exactas, Universidad Nacional de la Plata (Argentina)

    1997-12-31

    Vanadium compounds have been found to possess insulin- and growth factor-mimetic effects. In consequence, these derivatives are potentially useful as effective oral therapeutic agents in diabetic patients. However, their use has been limited by various toxic side-effects and by the low solubility of different derivatives. Recently, vanadium complexes with maltol, a sugar used as a common food additive, have been synthesised and investigated in animals, showing possible insulin-mimetic effects with low toxic side-effects. In the present study we have investigated the effect of bis(maltolato)oxovanadium (IV) (BMOV) and bis(maltolato)dioxovanadium (V) (BMV) on bone cells in culture as well as their direct effect on alkaline phosphatase in vitro. A comparison was also made with the action of vanadate and vanadyl cation. Vanadium compounds regulated cell proliferation in a biphasic manner with similar potencies. Osteoblast differentiation, assessed by alkaline phosphatase activity, was found to be dose-dependent, with the inhibitory effect being stronger for vanadate and BMOV than for vanadyl and BMV. All vanadium compounds directly inhibited bovine intestinal ALP with a similar potency. Thus, maltol vanadium derivatives behave in a similar way to vanadate and vanadyl in osteoblast-like UMR 106 cells in culture. (orig.)

  14. Ethanol and Other Short-Chain Alcohols Inhibit NLRP3 Inflammasome Activation through Protein Tyrosine Phosphatase Stimulation

    Science.gov (United States)

    Hoyt, Laura R.; Ather, Jennifer L.; Randall, Matthew J.; DePuccio, Daniel P.; Landry, Christopher C.; Wewers, Mark D.; Gavrilin, Mikhail A.; Poynter, Matthew E.

    2016-01-01

    Immunosuppression is a major complication of alcoholism that contributes to increased rates of opportunistic infections and sepsis in alcoholics. The NLRP3 inflammasome, a multi-protein intracellular pattern recognition receptor complex that facilitates the cleavage and secretion of the pro-inflammatory cytokines IL-1β and IL-18, can be inhibited by ethanol and we sought to better understand the mechanism through which this occurs and whether chemically similar molecules exert comparable effects. We show that ethanol can specifically inhibit activation of the NLRP3 inflammasome, resulting in attenuated IL-1β and caspase-1 cleavage and secretion, as well as diminished ASC speck formation, without affecting potassium efflux, in a mouse macrophage cell line (J774), mouse bone marrow derived dendritic cells, mouse neutrophils, and human PBMCs. The inhibitory effects on the Nlrp3 inflammasome were independent of GABAA receptor activation or NMDA receptor inhibition, but was associated with decreased oxidant production. Ethanol treatment markedly decreased cellular tyrosine phosphorylation, while administration of the tyrosine phosphatase inhibitor sodium orthovanadate prior to ethanol restored tyrosine phosphorylation and IL-1β secretion subsequent to ATP stimulation. Furthermore, sodium orthovanadate-induced phosphorylation of ASC Y144, necessary and sufficient for Nlrp3 inflammasome activation, and secretion of phosphorylated ASC, were inhibited by ethanol. Finally, multiple alcohol-containing organic compounds exerted inhibitory effects on the Nlrp3 inflammasome, whereas 2-methylbutane (isopentane), the analogous alkane of the potent inhibitor isoamyl alcohol (isopentanol), did not. Our results demonstrate that ethanol antagonizes the NLRP3 inflammasome at an apical event in its activation through the stimulation of protein tyrosine phosphatases, an effect shared by other short-chain alcohols. PMID:27421477

  15. TAMRA/TAMRA Fluorescence Quenching Systems for the Activity Assay of Alkaline Phosphatase.

    Science.gov (United States)

    Shiba, Akio; Kinoshita-Kikuta, Emiko; Kinoshita, Eiji; Koike, Tohru

    2017-08-15

    We introduce two types of fluorescence-quenching assay for alkaline phosphatases (APs) by using a carboxytetramethyl-rhodamine (TAMRA)-labeled phosphate-binding tag molecule (TAMRA-Phos-tag). In the first assay, TAMRA-labeled O -phosphorylethanolamine (TAMRA-PEA) was used as an artificial AP-substrate. TAMRA-Phos-tag specifically captured TAMRA-PEA to form a 1:1 complex at pH 7.4; the intensity of the fluorescence peak of the complex at 580 nm (λ ex = 523 nm) was significantly reduced to 32% of the average value for the two individual components as a result of the mutual approach of the TAMRA moieties. As TAMRA-PEA was dephosphorylated by AP, the resulting TAMRA-labeled ethanolamine dissociated and the fluorescence increased in a manner dependent on the AP dose and the time. In the second assay, pyrophosphate (PP), a natural AP-substrate, was used as a bridging ligand to form a dimeric TAMRA-Phos-tag complex. The dimerization reduced the fluorescence intensity to 49% of that in the absence of PP. As pyrophosphate was hydrolyzed to two orthophosphate moieties by AP, the 580-nm fluorescence recovered in a time-dependent manner. By examining the initial slope of this time-dependent fluorescence recovery, we succeeded in evaluating the 50% inhibitory concentrations of orthovanadate toward two AP isozymes under near-physiological conditions.

  16. Rapamycin Induces Mitogen-activated Protein (MAP) Kinase Phosphatase-1 (MKP-1) Expression through Activation of Protein Kinase B and Mitogen-activated Protein Kinase Kinase Pathways*

    Science.gov (United States)

    Rastogi, Ruchi; Jiang, Zhongliang; Ahmad, Nisar; Rosati, Rita; Liu, Yusen; Beuret, Laurent; Monks, Robert; Charron, Jean; Birnbaum, Morris J.; Samavati, Lobelia

    2013-01-01

    Mitogen-activated protein kinase phosphatase-1 (MKP-1), also known as dual specificity phosphatase-1 (DUSP-1), plays a crucial role in the deactivation of MAPKs. Several drugs with immune-suppressive properties modulate MKP-1 expression as part of their mechanism of action. We investigated the effect of mTOR inhibition through rapamycin and a dual mTOR inhibitor (AZD2014) on MKP-1 expression. Low dose rapamycin led to a rapid activation of both AKT and ERK pathways with a subsequent increase in MKP-1 expression. Rapamycin treatment led to phosphorylation of CREB, transcription factor 1 (ATF1), and ATF2, three transcription factors that bind to the cyclic AMP-responsive elements on the Mkp-1 promoter. Inhibition of either the MEK/ERK or the AKT pathway attenuated rapamycin-mediated MKP-1 induction. AZD2014 did not activate AKT but activated the ERK pathway, leading to a moderate MKP-1 induction. Using bone marrow-derived macrophages (BMDMs) derived from wild-type (WT) mice or mice deficient in AKT1 and AKT2 isoforms or BMDM from targeted deficiency in MEK1 and MEK2, we show that rapamycin treatment led to an increased MKP1 expression in BMDM from WT but failed to do so in BMDMs lacking the AKT1 isoform or MEK1 and MEK2. Importantly, rapamycin pretreatment inhibited LPS-mediated p38 activation and decreased nitric oxide and IL-6 production. Our work provides a conceptual framework for the observed immune modulatory effect of mTOR inhibition. PMID:24126911

  17. Trypanosoma cruzi: experimental Chagas' disease in Rhesus monkeys. II. Ultraestructural and cytochemical studies of peroxidase and acid phosphatase activities

    Directory of Open Access Journals (Sweden)

    Maria de Nazareth Leal de Meirelles

    1990-06-01

    Full Text Available Ultrastructural and cytochemical studies of peroxidase and acid phosphatase were performed in skin, lymph node and heart muscle tissue of thesus monkeys with experimental Chagas's disease. At the site of inoculation ther was a proliferative reaction with the presence of immature macrophages revealed by peroxidase technique. At the lymph node a difuse inflammatory exudate with mononuclear cells, fibroblasts and immature activated macrophages reproduces the human patrtern of acute Chagas' disease inflamatory lesions. The hearth muscle cells present different degrees of degenerative alterations and a striking increase in the number of lysosomal profiles that exhibit acid hydrolase reaction product. A strong inflammatory reaction was present due to lymphocytic infiltrate or due to eosinophil granulocytes associated to ruptured cells. The present study provides some experimental evidences that the monkey model could be used as a reliable model to characterize histopathological alterations of the human disease.

  18. Brominated polyunsaturated lipids with protein tyrosine phosphatase-1B inhibitory activity from Chinese marine sponge Xestospongia testudinaria.

    Science.gov (United States)

    He, Wen-Fei; Liang, Lin-Fu; Cai, You-Sheng; Gao, Li-Xin; Li, Yu-Fen; Li, Jia; Liu, Hai-Li; Guo, Yue-Wei

    2015-01-01

    A new brominated polyunsaturated lipid, methyl (E,E)-14,14-dibromo-4,6,13-tetradecatrienoate (1), along with three known related analogues (2-4), were isolated from the Et2O-soluble portion of the acetone extract of Chinese marine sponge Xestospongia testudinaria treated with diazomethane. The structure of the new compound was elucidated by detailed spectroscopic analysis and by comparison with literature data. Compound 3 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 5.30 ± 0.61 μM, when compared to the positive control oleanolic acid (IC50 = 2.39 ± 0.26 μM).

  19. Phosphoinositide 5-phosphatase activities control cell motility in glioblastoma: Two phosphoinositides PI(4,5)P2 and PI(3,4)P2 are involved.

    Science.gov (United States)

    Ramos, Ana Raquel; Elong Edimo, William's; Erneux, Christophe

    2018-01-01

    Inositol polyphosphate 5-phosphatases or phosphoinositide 5-phosphatases (PI 5-phosphatases) are enzymes that can act on soluble inositol phosphates and/or phosphoinositides (PIs). Several PI 5-phosphatases have been linked to human genetic diseases, in particular the Lowe protein or OCRL which is mutated in the Lowe syndrome. There are 10 different members of this family and 9 of them can use PIs as substrate. One of these substrates, PI(3,4,5)P3 binds to specific PH domains and recruits as effectors specific proteins to signaling complexes. Protein kinase B is one target protein and activation of the kinase will have a major impact on cell proliferation, survival and cell metabolism. Two other PIs, PI(4,5)P2 and PI(3,4)P2, are produced or used as substrates of PI 5-phosphatases (OCRL, INPP5B, SHIP1/2, SYNJ1/2, INPP5K, INPP5J, INPP5E). The inositol lipids may influence many aspects of cytoskeletal organization, lamellipodia formation and F-actin polymerization. PI 5-phosphatases have been reported to control cell migration, adhesion, polarity and cell invasion particularly in cancer cells. In glioblastoma, reducing SHIP2 expression can positively or negatively affect the speed of cell migration depending on the glioblastoma cell type. The two PI 5-phosphatases SHIP2 or SKIP could be localized at the plasma membrane and can reduce either PI(3,4,5)P3 or PI(4,5)P2 abundance. In the glioblastoma 1321 N1 cells, SHIP2 controls plasma membrane PI(4,5)P2 thereby participating in the control of cell migration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Assessment of the colorimetric and fluorometric assays for alkaline phosphatase activity in cow's, goat's, and sheep's milk.

    Science.gov (United States)

    Klotz, V; Hill, Art; Warriner, K; Griffiths, M; Odumeru, J

    2008-09-01

    Raw milk is a well-established vehicle for the carriage of human pathogens, and many regulatory bodies have consequently mandated compulsory pasteurization as a food safety intervention. The residual activity of alkaline phosphatase (ALP) has historically been used to verify the adequacy of pasteurization of cow's milk. However, there is uncertainty on how the current ALP standards and methods of analysis can be applied to sheep's and goat's milk, which naturally contain different levels of the enzyme than that found in cow's milk. The official ALP methods applied in Canada (colorimetric assay; MFO-3) and in the United States (Fluorophos) were assessed for their ability to detect enzyme activity in raw and pasteurized milk derived from cows, sheep, and goats. The detection limit and the limit of quantitation were 0.8 and 2.02 microg/ml phenol, respectively, for the MFO-3 method and 43 and 85 mU/liter, respectively, for the Fluorophos method. The average ALP levels in raw goat's, cow's, and sheep's milk were 165, 1,562, and 3,512 microg/ml phenol, respectively. Raw milk detection limits, which correspond to raw milk phosphatase levels, were 0.051, 0.485, and 0.023% in cow's, goat's, and sheep's milk, respectively, for the MFO-3 method and 0.007, 0.070, and 0.004%, respectively, for the Fluorophos method. Although both methods can be used for ALP determination in cow's, goat's, and sheep's milk, the Fluorophos assay was superior to the colorimetric MFO-3 method based on sensitivity and time required to complete the analysis.

  1. Gingival crevicular fluid alkaline phosphatase activity in relation to pubertal growth spurt and dental maturation: A multiple regression study

    Directory of Open Access Journals (Sweden)

    Perinetti, G.

    2016-04-01

    Full Text Available Introduction: The identification of the onset of the pubertal growth spurt has major clinical implications when dealing with orthodontic treatment in growing subjects. Aim: Through multivariate methods, this study evaluated possible relationships between the gingival crevicular fluid (GCF alkaline phosphatase (ALP activity and pubertal growth spurt and dentition phase. Materials and methods: One hundred healthy growing subjects (62 females, 38 males; mean age, 11.5±2.4 years were enrolled into this doubleblind, prospective, cross-sectional-design study. Phases of skeletal maturation (pre - pubertal, pubertal, post - pubertal was assessed using the cervical vertebral maturation method. Samples of GCF for the ALP activity determination were collected at the mesial and distal sites of the mandibular central incisors. The phases of the dentition were recorded as intermediate mixed, late mixed, or permanent. A multinomial multiple logistic regression model was used to assess relationships of the enzymatic activity to growth phases and dentition phases. Results: The GCF ALP activity was greater in the pubertal growth phase as compared to the pre - pubertal and post - pubertal growth phases. Significant adjusted odds ratios for the GCF ALP activity for the pre - pubertal and post - pubertal subjects, in relation to the pubertal group, were 0.76 and 0.84, respectively. No significant correlations were seen for the dentition phase. Conclusions: The GCF ALP activity is a valid candidate as a non - invasive biomarker for the identification of the pubertal growth spurt irrespective of the dentition phase.

  2. [Human serum alcaline phosphatase and ageing].

    Science.gov (United States)

    Negrão, M R; Martins, M J; Ramos, E; Barros, H; Hipólito-Reis, C; Azevedo, I

    2003-01-01

    In experimental ageing models an inverse relationship between age and alkaline phosphatase activity has been observed. To characterize serum levels of alkaline phosphatase activity in humans according to age and gender. Serum alkaline phosphatase was determined in a random sample of 203 community dwellers aged 40 or more years. In men (n=87) total serum alkaline phosphatase markedly increased from the 5th to the 6th decade and then stabilized. For women (n=116) there was a slight increase in total serum alkaline phosphatase from the 5th to the 6th decade, followed by a bend upward after 69 years of age. There was a significant positive correlation between total serum alkaline phosphatase and age for the whole population. Serum alkaline phosphatase activity appears as a biomarker of age in humans, similarly to what has been described for experimental animal models.

  3. Loss of SYNJ1 dual phosphatase activity leads to early onset refractory seizures and progressive neurological decline

    DEFF Research Database (Denmark)

    Hardies, Katia; Cai, Yiying; Jardel, Claude

    2016-01-01

    SYNJ1 encodes a polyphosphoinositide phosphatase, synaptojanin 1, which contains two consecutive phosphatase domains and plays a prominent role in synaptic vesicle dynamics. Autosomal recessive inherited variants in SYNJ1 have previously been associated with two different neurological diseases: a...... with severe epilepsy, and emphasize the importance of this biological pathway in seizure pathophysiology....

  4. Active Particles on Curved Surfaces

    OpenAIRE

    Fily, Yaouen; Baskaran, Aparna; Hagan, Michael F.

    2016-01-01

    Recent studies have highlighted the sensitivity of active matter to boundaries and their geometries. Here we develop a general theory for the dynamics and statistics of active particles on curved surfaces and illustrate it on two examples. We first show that active particles moving on a surface with no ability to probe its curvature only exhibit steady-state inhomogeneities in the presence of orientational order. We then consider a strongly confined 3D ideal active gas and compute its steady-...

  5. A Role for Protein Phosphatase 2A in Regulating p38 Mitogen Activated Protein Kinase Activation and Tumor Necrosis Factor-Alpha Expression during Influenza Virus Infection

    Directory of Open Access Journals (Sweden)

    Anna H. Y. Law

    2013-04-01

    Full Text Available Influenza viruses of avian origin continue to pose pandemic threats to human health. Some of the H5N1 and H9N2 virus subtypes induce markedly elevated cytokine levels when compared with the seasonal H1N1 virus. We previously showed that H5N1/97 hyperinduces tumor necrosis factor (TNF-alpha through p38 mitogen activated protein kinase (MAPK. However, the detailed mechanisms of p38MAPK activation and TNF-alpha hyperinduction following influenza virus infections are not known. Negative feedback regulations of cytokine expression play important roles in avoiding overwhelming production of proinflammatory cytokines. Here we hypothesize that protein phosphatases are involved in the regulation of cytokine expressions during influenza virus infection. We investigated the roles of protein phosphatases including MAPK phosphatase-1 (MKP-1 and protein phosphatase type 2A (PP2A in modulating p38MAPK activation and downstream TNF-alpha expressions in primary human monocyte-derived macrophages (PBMac infected with H9N2/G1 or H1N1 influenza virus. We demonstrate that H9N2/G1 virus activated p38MAPK and hyperinduced TNF-alpha production in PBMac when compared with H1N1 virus. H9N2/G1 induced PP2A activity in PBMac and, with the treatment of a PP2A inhibitor, p38MAPK phosphorylation and TNF-alpha production were further increased in the virus-infected macrophages. However, H9N2/G1 did not induce the expression of PP2A indicating that the activation of PP2A is not mediated by p38MAPK in virus-infected PBMac. On the other hand, PP2A may not be the targets of H9N2/G1 in the upstream of p38MAPK signaling pathways since H1N1 also induced PP2A activation in primary macrophages. Our results may provide new insights into the control of cytokine dysregulation.

  6. The CD45 protein tyrosine phosphatase is required for the completion of the activation program leading to lymphokine production in the Jurkat human T cell line

    NARCIS (Netherlands)

    Peyron, J. F.; Verma, S.; de Waal Malefyt, R.; Sancho, J.; Terhorst, C.; Spits, H.

    1991-01-01

    Stimulation of the T cell antigen receptor, TCR-CD3, induces tyrosine phosphorylation of specific cellular proteins through activation of a tyrosine kinase. The possible regulatory role of the CD45 protein tyrosine phosphatase in this process was explored by studying the functional properties of

  7. The use of the tyrosine phosphatase antagonist orthovanadate in the study of a cell proliferation inhibitor

    Science.gov (United States)

    Enebo, D. J.; Hanek, G.; Fattaey, H. K.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    Incubation of murine fibroblasts with orthovanadate, a global tyrosine phosphatase inhibitor, was shown to confer a "pseudo-transformed" phenotype with regard to cell morphology and growth characteristics. This alteration was manifested by both an increasing refractile appearance of the cells, consistent with many transformed cell lines, as well as an increase in maximum cell density was attained. Despite the abrogation of cellular tyrosine phosphatase activity, orthovanadate-treated cells remained sensitive to the biological activity of a naturally occurring sialoglycopeptide (SGP) cell surface proliferation inhibitor. The results indicated that tyrosine phosphatase activity, inhibited by orthovanadate, was not involved in the signal transduction pathway of the SGP.

  8. Ubiquitination of the bacterial inositol phosphatase, SopB, regulates its biological activity at the plasma membrane.

    LENUS (Irish Health Repository)

    Knodler, Leigh A

    2009-11-01

    The Salmonella type III effector, SopB, is an inositol polyphosphate phosphatase that modulates host cell phospholipids at the plasma membrane and the nascent Salmonella-containing vacuole (SCV). Translocated SopB persists for many hours after infection and is ubiquitinated but the significance of this covalent modification has not been investigated. Here we identify by mass spectrometry six lysine residues of SopB that are mono-ubiquitinated. Substitution of these six lysine residues with arginine, SopB-K(6)R, almost completely eliminated SopB ubiquitination. We found that ubiquitination does not affect SopB stability or membrane association, or SopB-dependent events in SCV biogenesis. However, two spatially and temporally distinct events are dependent on ubiquitination, downregulation of SopB activity at the plasma membrane and prolonged retention of SopB on the SCV. Activation of the mammalian pro-survival kinase Akt\\/PKB, a downstream target of SopB, was intensified and prolonged after infection with the SopB-K(6)R mutant. At later times, fewer SCV were decorated with SopB-K(6)R compared with SopB. Instead SopB-K(6)R was present as discrete vesicles spread diffusely throughout the cell. Altogether, our data show that ubiquitination of SopB is not related to its intracellular stability but rather regulates its enzymatic activity at the plasma membrane and intracellular localization.

  9. Hepatocyte nuclear factor 1alpha is an accessory factor required for activation of glucose-6-phosphatase gene transcription by glucocorticoids.

    Science.gov (United States)

    Lin, B; Morris, D W; Chou, J Y

    1998-11-01

    Deficiency of glucose-6-phosphatase (G6Pase), a key enzyme in glucose homeostasis, causes glycogen storage disease type 1a (GSD-1a), also know as von Gierke disease. Expression of the G6Pase gene is regulated by multiple hormones, including glucocorticoids. The synthetic glucocorticoid dexamethasone increased G6Pase mRNA abundance and gene transcription in H4-IIE hepatoma cells. Transient transfection assays demonstrated that the G6Pase promoter was active in H4-IIE cells only in the presence of dexamethasone. The minimal G6Pase promoter was contained within nucleotides -234/+3, which has two putative glucocorticoid response elements (GREs) at nucleotides -178/-164 (site 1) and -154/-140 (site 2). Electromobility shift and transient transfection assays showed that only GRE site 1 was required for glucocorticoid-activated transcription from the G6Pase promoter. Deletion analysis demonstrated that the DNA elements absolutely essential for glucocorticoid-stimulated transcription from the G6Pase promoter were contained within nucleotides -234/-212, encompassing binding motifs for hepatocyte nuclear factors (HNFs) 1 (-226/-212) and 4 (-231/-220). Electromobility shift and cotransfection assays showed that HNF1alpha bound to its cognate site and mediated transcription activation of the G6Pase gene by glucocorticoids.

  10. Resistance imparted by traditional Chinese medicines to the acute change of glutamic pyruvic transaminase, alkaline phosphatase and creatine kinase activities in rat blood caused by noise.

    Science.gov (United States)

    Zhu, Bei-Wei; Sun, Yu-Mei; Yun, Xia; Han, Song; Piao, Mei-Lan; Murata, Yoshiyuki; Tada, Mikiro

    2004-05-01

    The activities of serum glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP) and creatine kinase (CK) in rats injected or not with the Chinese medicines, Astragali, Rhodiolae and Ligusticum, were determined after noise exposure. Noise at 95 and 105 dB significantly increased the activities of GPT, ALP and CK, and showed a dependence on the exposure time. The injection of each medicine significantly suppressed the increased enzyme activities by 95 and 105 dB noise.

  11. Cloning and characterization of two genes restoring acid phosphatase activity in pho1- mutants of Schizosaccharomyces pombe.

    Science.gov (United States)

    Maundrell, K; Nurse, P; Schönholzer, F; Schweingruber, M E

    1985-01-01

    Schizosaccharomyces pombe acid phosphatase (APh) is a secreted cell surface glycoprotein which is deficient in pho1 mutants. By screening an S. pombe gene bank for sequences which can functionally rescue the pho1-44 mutation, we have isolated two genomic clones carried in plasmids pSp4B and pSp4C/2. These two sequences map of different genetic loci and show no cross hybridization by Southern blotting. pSp4C/2 was found to contain the PHO1 gene, and cells transformed with this plasmid produce a protein which cross-reacts with antibodies raised against the protein moiety of APh. Data from Northern blotting experiments show that pSp4C/2 encodes a 1.6-kb transcript, and that mRNA levels are increased when cells are grown in low concentrations of inorganic phosphate. The results indicate that pSp4C/2 contains the structural gene for APh, PHO1, whereas pSp4B appears to carry a gene coding for a minor species of APh, PHO4 which is not regulated by extracellular phosphate.

  12. LptO (PG0027) Is Required for Lipid A 1-Phosphatase Activity in Porphyromonas gingivalis W50.

    Science.gov (United States)

    Rangarajan, Minnie; Aduse-Opoku, Joseph; Hashim, Ahmed; McPhail, Graham; Luklinska, Zofia; Haurat, M Florencia; Feldman, Mario F; Curtis, Michael A

    2017-06-01

    Porphyromonas gingivalis produces outer membrane vesicles (OMVs) rich in virulence factors, including cysteine proteases and A-LPS, one of the two lipopolysaccharides (LPSs) produced by this organism. Previous studies had suggested that A-LPS and PG0027, an outer membrane (OM) protein, may be involved in OMV formation. Their roles in this process were examined by using W50 parent and the Δ PG0027 mutant strains. Inactivation of PG0027 caused a reduction in the yield of OMVs. Lipid A from cells and OMVs of P. gingivalis W50 and the Δ PG0027 mutant strains were analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Lipid A from W50 cells contained bis-P-pentaacyl, mono-P-pentaacyl, mono-P-tetraacyl, non-P-pentaacyl, and non-P-tetraacyl species, whereas lipid A from Δ PG0027 mutant cells contained only phosphorylated species; nonphosphorylated species were absent. MALDI-TOF/TOF tandem MS of mono-P-pentaacyl ( m / z 1,688) and mono-P-tetraacyl ( m / z 1,448) lipid A from Δ PG0027 showed that both contained lipid A 1-phosphate, suggesting that the Δ PG0027 mutant strain lacked lipid A 1-phosphatase activity. The total phosphatase activities in the W50 and the Δ PG0027 mutant strains were similar, whereas the phosphatase activity in the periplasm of the Δ PG0027 mutant was lower than that in W50, supporting a role for PG0027 in lipid A dephosphorylation. W50 OMVs were enriched in A-LPS, and its lipid A did not contain nonphosphorylated species, whereas lipid A from the Δ PG0027 mutant (OMVs and cells) contained similar species. Thus, OMVs in P. gingivalis are apparently formed in regions of the OM enriched in A-LPS devoid of nonphosphorylated lipid A. Conversely, dephosphorylation of lipid A through a PG0027-dependent process is required for optimal formation of OMVs. Hence, the relative proportions of nonphosphorylated and phosphorylated lipid A appear to be crucial for OMV formation in this organism. IMPORTANCE

  13. Dimerization inhibits the activity of receptor-like protein-tyrosine phosphatase-alpha

    DEFF Research Database (Denmark)

    Jiang, G; den Hertog, J; Su, J

    1999-01-01

    that dimerization can negatively regulate activity, through the interaction of an inhibitory 'wedge' on one monomer with the catalytic cleft of domain 1 in the other monomer. Here we show that dimerization inhibits the activity of a full-length RPTP in vivo. We generated stable disulphide-bonded full...

  14. Modulation of Src Activity by Low Molecular Weight Protein Tyrosine Phosphatase During Osteoblast Differentiation

    NARCIS (Netherlands)

    Zambuzzi, Willian F.; Granjeiro, Jose M.; Parikh, Kaushal; Yuvaraj, Saravanan; Peppelenbosch, Maikel P.; Ferreira, Carmen V.

    2008-01-01

    Background: Src kinase plays a critical role in bone metabolism, particularly in osteoclasts. However, the ability of Src kinase to modulate the activity of other bone cells is less well understood. In this work, we examined the expression and activity of Src and low molecular weight protein

  15. Adiponectin haploinsufficiency promotes mammary tumor development in MMTV-PyVT mice by modulation of phosphatase and tensin homolog activities.

    Directory of Open Access Journals (Sweden)

    Janice B B Lam

    Full Text Available Adiponectin is an adipokine possessing beneficial effects on obesity-related medical complications. A negative association of adiponectin levels with breast cancer development has been demonstrated. However, the precise role of adiponectin deficiency in mammary carcinogenesis remains elusive.In the present study, MMTV-polyomavirus middle T antigen (MMTV-PyVT transgenic mice with reduced adiponectin expressions were established and the stromal effects of adiponectin haploinsufficiency on mammary tumor development evaluated. In mice from both FVB/N and C57BL/6J backgrounds, insufficient adiponectin production promoted mammary tumor onset and development. A distinctive basal-like subtype of tumors, with a more aggressive phenotype, was derived from adiponectin haplodeficient MMTV-PyVT mice. Comparing with those from control MMTV-PyVT mice, the isolated mammary tumor cells showed enhanced tumor progression in re-implanted nude mice, accelerated proliferation in primary cultures, and hyperactivated phosphatidylinositol-3-kinase (PI3K/Akt/beta-catenin signaling, which at least partly attributed to the decreased phosphatase and tensin homolog (PTEN activities. Further analysis revealed that PTEN was inactivated by a redox-regulated mechanism. Increased association of PTEN-thioredoxin complexes was detected in tumors derived from mice with reduced adiponectin levels. The activities of thioredoxin (Trx1 and thioredoxin reductase (TrxR1 were significantly elevated, whereas treatment with either curcumin, an irreversible inhibitor of TrxR1, or adiponectin largely attenuated their activities and resulted in the re-activation of PTEN in these tumor cells. Moreover, adiponectin could inhibit TrxR1 promoter-mediated transcription and restore the mRNA expressions of TrxR1.Adiponectin haploinsufficiency facilitated mammary tumorigenesis by down-regulation of PTEN activity and activation of PI3K/Akt signalling pathway through a mechanism involving Trx1/TrxR1

  16. Dissolved organic phosphorus utilization and alkaline phosphatase activity of the dinoflagellate Gymnodinium impudicum isolated from the South Sea of Korea

    Science.gov (United States)

    Oh, Seok Jin; Kwon, Hyeong Kyu; Noh, Il Hyeon; Yang, Han-Soeb

    2010-09-01

    This study investigated alkaline phosphatase (APase) activity and dissolved organic and inorganic phosphorus utilization by the harmful dinoflagellate Gymnodinium impudicum (Fraga et Bravo) Hansen et Moestrup isolated from the South Sea of Korea. Under conditions of limited phosphorus, observation of growth kinetics in batch culture yielded a maximum growth rate (μmax) of 0.41 /day and a half saturation constant (Ks) of 0.71 μM. In time-course experiments, APase was induced as dissolved inorganic phosphorus (DIP) concentrations fell below 0.83 μM, a threshold near the estimated Ks; APase activity increased with further DIP depletion to a maximum of 0.70 pmol/cell/h in the senescent phase. Thus, Ks may be an important index of the threshold DIP concentration for APase induction. G. impudicum utilizes a wide variety of dissolved organic phosphorus compounds in addition to DIP. These results suggest that DIP limitation in the Southern Sea of Korea may have led to the spread of G. impudicum along with the harmful dinoflagellate Cochlodinium polykrikoides in recent years.

  17. Disposable lateral flow-through strip for smartphone-camera to quantitatively detect alkaline phosphatase activity in milk.

    Science.gov (United States)

    Yu, Ling; Shi, ZhuanZhuan; Fang, Can; Zhang, YuanYuan; Liu, YingShuai; Li, ChangMing

    2015-07-15

    A disposable lateral flow-through strip was developed for smartphone to fast one-step quantitatively detect alkaline phosphatase (ALP) activity in raw milk. The strip comprises two functional components, a conjugation pad loaded with phosphotyrosine-coated gold nanoparticles (AuNPs@Cys-Try-p) and a testing line coated with anti-phosphotryosine antibody (anti-Tyr-p mAb). The dephosphorylation activity of ALP at the testing zone can be quantitatively assayed by monitoring the accumulated AuNPs-induced color changes by smartphone camera, thus providing a highly convenient portable detection method. A trace amount of ALP as low as 0.1UL(-1) with a linear dynamic range of 0.1-150UL(-1) (R(2)=0.999) in pasteurized milk and raw milk can be one-step detected by the developed flow-through strip within 10min, demonstrating the potential of smartphone-based portable sensing device for pathogen detection. This bio-hazards free lateral flow-through testing strip can be also used to fabricate rapid, sensitive and inexpensive enzyme or immunosensors for broad portable clinic diagnosis and food contamination analysis, particularly in point-of-care and daily food quality inspection. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Avicin D: a protein reactive plant isoprenoid dephosphorylates Stat 3 by regulating both kinase and phosphatase activities.

    Directory of Open Access Journals (Sweden)

    Valsala Haridas

    Full Text Available Avicins, a class of electrophilic triterpenoids with pro-apoptotic, anti-inflammatory and antioxidant properties, have been shown to induce redox-dependant post-translational modification of cysteine residues to regulate protein function. Based on (a the cross-talk that occurs between redox and phosphorylation processes, and (b the role of Stat3 in the process of apoptosis and carcinogenesis, we chose to study the effects of avicins on the processes of phosphorylation/dephosphorylation in Stat3. Avicins dephosphorylate Stat3 in a variety of human tumor cell lines, leading to a decrease in the transcriptional activity of Stat3. The expression of Stat3-regulated proteins such as c-myc, cyclin D1, Bcl2, survivin and VEGF were reduced in response to avicin treatment. Underlying avicin-induced dephosphorylation of Stat3 was dephosphorylation of JAKs, as well as activation of protein phosphatase-1. Downregulation of both Stat3 activity and expression of Stat 3-controlled pro-survival proteins, contributes to the induction of apoptosis in avicin treated tumor cells. Based on the role of Stat3 in inflammation and wounding, and the in vivo inhibition of VEGF by avicins in a mouse skin carcinogenesis model, it is likely that avicin-induced inhibition of Stat3 activity results in the suppression of the pro-inflammatory and pro-oxidant stromal environment of tumors. Activation of PP-1, which also acts as a cellular economizer, combined with the redox regulation by avicins, can aid in redirecting metabolism from growth promoting anabolic to energy sparing pathways.

  19. Phosphorus compounds, proteins, nuclease and acid phosphatase activities in isolated spinach chloroplasts

    Directory of Open Access Journals (Sweden)

    E. Mikulska

    2015-01-01

    Full Text Available This paper deals with attempts to elaborate a simple method of spinach chloroplast isolation ensuring a high proportion of intact chloroplasts. We obtained 3 preparations of isolated chloroplasts. Several preliminary analyses of the obtained chloroplast fraction were also performed. Phosphorus compounds, total protein and the enzyme activities of RNase, DNase and GPase were determined. We found: 0,36-0,59% of RNA, 0,19-0,24% of DNA, 2,1-2,9% of phospholipids and 26-28% of protein. RNase activity was very high.

  20. PME-1 protects extracellular signal-regulated kinase pathway activity from protein phosphatase 2A-mediated inactivation in human malignant glioma.

    Science.gov (United States)

    Puustinen, Pietri; Junttila, Melissa R; Vanhatupa, Sari; Sablina, Anna A; Hector, Melissa E; Teittinen, Kaisa; Raheem, Olayinka; Ketola, Kirsi; Lin, Shujun; Kast, Juergen; Haapasalo, Hannu; Hahn, William C; Westermarck, Jukka

    2009-04-01

    Extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase pathway activity is regulated by the antagonist function of activating kinases and inactivating protein phosphatases. Sustained ERK pathway activity is commonly observed in human malignancies; however, the mechanisms by which the pathway is protected from phosphatase-mediated inactivation in the tumor tissue remain obscure. Here, we show that methylesterase PME-1-mediated inhibition of the protein phosphatase 2A promotes basal ERK pathway activity and is required for efficient growth factor response. Mechanistically, PME-1 is shown to support ERK pathway signaling upstream of Raf, but downstream of growth factor receptors and protein kinase C. In malignant gliomas, PME-1 expression levels correlate with both ERK activity and cell proliferation in vivo. Moreover, PME-1 expression significantly correlates with disease progression in human astrocytic gliomas (n=222). Together, these observations identify PME-1 expression as one mechanism by which ERK pathway activity is maintained in cancer cells and suggest an important functional role for PME-1 in the disease progression of human astrocytic gliomas.

  1. Joint effect of phosphorus limitation and temperature on alkaline phosphatase activity and somatic growth in Daphnia magna.

    Science.gov (United States)

    Wojewodzic, Marcin W; Kyle, Marcia; Elser, James J; Hessen, Dag O; Andersen, Tom

    2011-04-01

    Alkaline phosphatase (AP) is a potential biomarker for phosphorus (P) limitation in zooplankton. However, knowledge about regulation of AP in this group is limited. In a laboratory acclimation experiment, we investigated changes in body AP concentration for Daphnia magna kept for 6 days at 10, 15, 20 and 25 °C and fed algae with 10 different molar C:P ratios (95-660). In the same experiment, we also assessed somatic growth of the animals since phosphorus acquisition is linked to growth processes. Overall, non-linear but significant relationships of AP activity with C:P ratio were observed, but there was a stronger impact of temperature on AP activity than of P limitation. Animals from the lowest temperature treatment had higher normalized AP activity, which suggests the operation of biochemical temperature compensation mechanisms. Body AP activity increased by a factor of 1.67 for every 10 °C decrease in temperature. These results demonstrate that temperature strongly influences AP expression. Therefore, using AP as a P limitation marker in zooplankton needs to consider possible confounding effects of temperature. Both temperature and diet affected somatic growth. The temperature effect on somatic growth, expressed as the Q (10) value, responded non-linearly with C:P, with Q(10) ranging between 1.9 for lowest food C:P ratio and 1.4 for the most P-deficient food. The significant interaction between those two variables highlights the importance of studying temperature-dependent changes of growth responses to food quality.

  2. Direct regulation of transforming growth factor ??induced epithelial?mesenchymal transition by the protein phosphatase activity of unphosphorylated PTEN in lung cancer cells

    OpenAIRE

    Kusunose, Masaaki; Hashimoto, Naozumi; Kimura, Motohiro; Ogata, Ryo; Aoyama, Daisuke; Sakamoto, Koji; Miyazaki, Shinichi; Ando, Akira; Omote, Norihito; Imaizumi, Kazuyoshi; Kawabe, Tsutomu; Hasegawa, Yoshinori

    2015-01-01

    Transforming growth factor ? (TGF?) causes the acquisition of epithelial?mesenchymal transition (EMT). Although the tumor suppressor gene PTEN (phosphatase and tensin homologue deleted from chromosome 10) can negatively regulate many signaling pathways activated by TGF?, hyperactivation of these signaling pathways is observed in lung cancer cells. We recently showed that PTEN might be subject to TGF??induced phosphorylation of its C?terminus, resulting in a loss of its enzyme activities; PTEN...

  3. Effects of garlic and diallyl trisulfide on the growth, photosynthesis, and alkaline phosphatase activity of the toxic cyanobacterium Microcystis aeruginosa.

    Science.gov (United States)

    Wang, Shoubing; Wang, Yuanan; Ma, Xiaoxue; Xu, Ziran

    2016-03-01

    To identify a botanical algicide and elucidate the response of cyanobacteria to the extract from higher plants, the effects of garlic and garlic-derived diallyl trisulfide on Microcystis aeruginosa were studied. Effects were evaluated by changes in cell density, chlorophyll a, maximum effective quantum yield (Fv/Fm), effective quantum yield (YII), non-photochemical quenching (NPQ), and rapid light curves of M. aeruginosa. In addition, alkaline phosphatase activity (APA) was measured when M. aeruginosa was incubated with diallyl trisulfide. Results indicated that the inhibition by garlic and diallyl trisulfide was significant. The 120-h 50 % effective concentrations of garlic and diallyl trisulfide (EC50) were 0.75 g L(-1) and 2.84 mg L(-1), respectively. Moreover, the inhibitory rate increased with increasing concentration and the growth of M. aeruginosa was inhibited by 90.0 % at the highest concentrations. We also show that the response of M. aeruginosa to stress could involve both impairment of the photosynthetic center PSII and alteration of APA. For example, at high garlic concentration (2.0 g L(-1)), Fv/Fm significantly decreased from 0.501 to 0.084 (p garlic as an environmentally friendly algicide.

  4. Modulation of insulin action by vanadate: evidence of a role for phosphotyrosine phosphatase activity to alter cellular signaling.

    Science.gov (United States)

    Fantus, I G; Deragon, G; Lai, R; Tang, S

    A number of vanadium compounds (vanadate, vanadyl sulfate, metavanadate) have insulin-mimicking actions both in vitro and in vivo. They have multiple biological effects in cultured cells and interact directly with various enzymes. The inhibitory action on phosphoprotein tyrosine phosphatases (PTPs) and enhancement of cellular tyrosine phosphorylation appear to be the most relevant to explain the ability to mimic insulin. We demonstrated that in rat adipocytes both acute insulin effects, e.g. stimulation of IGF-II and transferrin binding and a chronic effect, insulin receptor downregulation, were stimulated by vanadate. Vanadate also enhanced insulin binding, particularly at very low insulin concentrations, associated with increased receptor affinity. This resulted in increased adipocyte insulin sensitivity. Finally vanadate augmented the extent of activation of the insulin receptor kinase by submaximal insulin concentrations. This was associated with a prolongation of the insulin biological response, lipogenesis, after removal of hormone. in rat adipocytes vanadate promotes insulin action by three mechanisms, 1) a direct insulin-mimetic action, 2) an enhancement of insulin sensitivity and 3) a prolongation of insulin biological response. These data suggest that PTP inhibitors have potential as useful therapeutic agents in insulin-resistant and relatively insulin-deficient forms of diabetes mellitus.

  5. High frequencies of elevated alkaline phosphatase activity and rickets exist in extremely low birth weight infants despite current nutritional support.

    Science.gov (United States)

    Mitchell, Shannon M; Rogers, Stefanie P; Hicks, Penni D; Hawthorne, Keli M; Parker, Bruce R; Abrams, Steven A

    2009-07-29

    Osteopenia and rickets are common among extremely low birth weight infants (ELBW, alkaline phosphatase activity (P-APA) in ELBW infants and evaluate our experience with the diagnosis of rickets in these infants. We evaluated all ELBW infants admitted to Texas Children's Hospital NICU in 2006 and 2007. Of 211 admissions, we excluded 98 patients who were admitted at >30 days of age or did not survive/stay for >6 weeks. Bone radiographs obtained in 32 infants were reviewed by a radiologist masked to laboratory values. In this cohort of 113 infants, P-APA was found to have a significant inverse relationship with BW, gestational age and serum phosphorus. In paired comparisons, P-APA of infants nutrition greater than 3 to 4 weeks, or clinical suspicion. Of these, 18 showed radiologic rickets and 14 showed osteopenia without rickets. Infants with BW 600 IU/L was very common in ELBW infants. BW was significantly inversely related to both P-APA and radiologic rickets. No single value of P-APA was related to radiological findings of rickets. Given the very high risk of osteopenia and rickets among ELBW infants, we recommend consideration of early screening and early mineral supplementation, especially among infants <600 g BW.

  6. Relation of fatty acid composition in lead-exposed mallards to fat mobilization, lipid peroxidation and alkaline phosphatase activity

    Science.gov (United States)

    Mateo, R.; Beyer, W.N.; Spann, J.W.; Hoffman, D.J.

    2003-01-01

    The increase of n-6 polyunsaturated fatty acids (PUFA) in animal tissues has been proposed as a mechanism of lead (Pb) poisoning through lipid peroxidation or altered eicosanoids metabolism. We have studied fatty acid (FA) composition in liver and brain of mallards (Anas platyrhynchos) feeding for 3 weeks on diets containing combinations of low or high levels of vitamin E (20 or 200 UI/kg) and Pb (0 or 2 g/kg). Saturated FA, n-6 PUFA and total concentrations of FA were higher in livers of Pb-exposed mallards, but not in their brains. The percentage of n-6 PUFA in liver and brain was slightly higher in Pb-exposed mallards. The increase of n-6 PUFA in liver was associated with decreased triglycerides and increased cholesterol in plasma, thus could be in part attributed to feed refusal and fat mobilization. The hepatic ratios between adrenic acid (22:4 n-6) and arachidonic acid (20:4 n-6) or between adrenic acid and linoleic acid (18:2 n-6) were higher in Pb exposed birds, supporting the existing hypothesis of increased fatty acid elongation by Pb. Among the possible consequences of increased n-6 PUFA concentration in tissues, we found increased lipid peroxidation in liver without important histopathological changes, and decreased plasma alkaline phosphatase activity that may reflect altered bone metabolism in birds.

  7. Specific expression and activity of acid phosphatases in common bean nodules

    OpenAIRE

    Bargaz, Adnane; Ghoulam, Cherki; Drevon, Jean-Jacques

    2013-01-01

    Under phosphorus (P) deficiency, sensitivity of the N2-fixing legumes increases since the large amount of P-dependent carbon and energy turnover required during N2 fixation are not satisfied. However, despites the fact that these crops have been widely characterized under P-deficiency and a number of tolerance traits have been identified, abilities of the nodules to cope with this environmental constraint have still to be further investigated. Increases both of activity and gene expression of...

  8. Distinct expression of alkaline phosphatase activity in epilimnetic bacteria: Implication for persistent DOC consumption in a P-limited reservoir

    Science.gov (United States)

    Tseng, Y.; Kao, S.; Shiah, F.

    2013-12-01

    In a P-deficient system, P availability usually controls the microbial activity and thus the ecosystem function. Thingstad et al. (1997) first addressed a 'Malfunctioning Microbial-loop' theory, which stated that low bacterial production (BP) caused by insufficient nutrient supply would result in DOC accumulation in an oligotrophic ecosystem. In this study we re-examined the theory by conducting seasonal patterns and correlations among soluble reactive phosphate (SRP) and DOC, microbial abundances (picocyanobacteria, bacteria, and heterotrophic nanoflagellate; HNF) and activities (primary production, bacterial production, and alkaline phosphatase activity; APA) coupled with enzyme-labeled fluorescence (ELF) assays on bacterioplankton in a subtropical reservoir sharing the common features, nitrate-replete and P-deficient, with most natural freshwater system during Oct 2007-Oct 2008. Persistently high APA was recorded during most of time, implying that the system was P-deficient. Size fractionated APA and ELF assay revealed that bacteria were the major APA contributor. However, significantly low epilimnion DOC was recorded during the stratified summer season accompanying with high BP and APA as well as high PP, implying that heterotrophic bacteria can well sustain in P-deficient system by utilizing DOP to rapidly lower down DOC under relatively high PP. Such findings oppose the 'Malfunctioning Microbial-loop' theory. On the other hand, strong epilimnetic DOC accumulation occurred in Oct 2007 under low light and low PP condition accompanying with high abundance of HNF, implying that HNF grazing may contribute to a certain degree of DOC accumulation. Correlation matrix supported our suggestions. This study testified the DOC dynamics in P-deficient ecosystem are tightly coupled with the source (PP and grazing) and sink (BP). We also suggested that in SRP-limited freshwater systems bacteria are capable of breaking down autochthonous DOC to reduce the chance of DOC

  9. Manure biochar influence upon soil properties, phosphorus distribution and phosphatase activities: A microcosm incubation study.

    Science.gov (United States)

    Jin, Yi; Liang, Xinqiang; He, Miaomiao; Liu, Yu; Tian, Guangming; Shi, Jiyan

    2016-01-01

    Using manure-derived-biochar as an alternative phosphorus (P) source has bright future prospects to improve soil P status. A 98-day microcosm incubation experiment was set up for two soils which were amended with manure biochar at proportions of 0, 0.5% and 1.5%. Swine manure samples were air-dried and manure biochar was prepared by pyrolysis at 400 °C for 4 h. As determined by P-31 nuclear magnetic resonance ((31)P NMR) spectroscopy, manure biochar mainly increased the contents and fractions of orthophosphate and pyrophosphate in two soils, while decreased those of monoesters (P<0.05). At the end of incubation, 1.5% of manure biochar raised soil pH by 0.5 and 0.6 units, cation exchange capacity by 16.9% and 32.2%, and soil total P by 82.1% and 81.1% for silt loam and clay loam soils, respectively, as compared with those soils without biochar. Simultaneously, 1.5% of manure biochar decreased acid phosphomonoesterase activities by 18.6% and 34.0% for clay loam and silt loam, respectively; while it increased alkaline phosphomonoesterase activities by 28.5% and 95.1% for clay loam and silt loam, respectively. The enhancement of soil P availability after manure biochar addition was firstly due to the orthophosphate and pyrophosphate as the major P species in manure biochar which directly increased contents of soil inorganic P, and also attributed to the decomposition of some organic P like monoesters by enhanced alkaline phosphomonoesterase activities from manure biochar addition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Effect of the presence of cholesterol in the interfacial microenvironment on the modulation of the alkaline phosphatase activity during in vitro mineralization.

    Science.gov (United States)

    Favarin, B Z; Andrade, M A R; Bolean, M; Simão, A M S; Ramos, A P; Hoylaerts, M F; Millán, J L; Ciancaglini, P

    2017-07-01

    Mineralization of the skeleton starts within cell-derived matrix vesicles (MVs); then, minerals propagate to the extracellular collagenous matrix. Tissue-nonspecific alkaline phosphatase (TNAP) degrades inorganic pyrophosphate (PP i ), a potent inhibitor of mineralization, and contributes P i (Phosphate) from ATP to initiate mineralization. Compared to the plasma membrane, MVs are rich in Cholesterol (Chol) (∼32%) and TNAP, but how Chol influences TNAP activity remains unclear. We have reconstituted TNAP in liposomes of dipalmitoylphosphatidylcholine (DPPC) or dioleoylphosphatidylcholine (DOPC) combined with Chol or its derivatives Cholestenone (Achol) and Ergosterol (Ergo). DPPC plus 36% sterols in liposome increased the catalytic activity of TNAP toward ATP. The presence of Chol also increased the propagation of minerals by 3.4-fold. The catalytic efficiency of TNAP toward ATP was fourfold lower in DOPC proteoliposomes as compared to DPPC proteoliposomes. DOPC proteoliposomes also increased biomineralization by 2.8-fold as compared to DPPC proteoliposomes. TNAP catalyzed the hydrolysis of ATP more efficiently in the case of the proteoliposome consisting of DOPC with 36% Chol. The same behavior emerged with Achol and Ergo. The organization of the lipid and the structure of the sterol influenced the surface tension (γ), the TNAP phosphohydrolytic activity in the monolayer, and the TNAP catalytic efficiency in the bilayers. Membranes in the Lα phase (Achol) provided better kinetic parameters as compared to membranes in the Lo phase (Chol and Ergo). In conclusion, the physical properties and the lateral organization of lipids in proteoliposomes are crucial to control mineral propagation mediated by TNAP activity during mineralization. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. 1H, 15N, 13C Resonance Assignments of the Reduced and Active Form of Human Protein Tyrosine Phosphatase, PRL-1

    Science.gov (United States)

    Skinner, Andria L.; Laurence, Jennifer S.

    2009-01-01

    Phosphatase of regenerating liver-1 (PRL-1) is a novel target for potentially treating cancer metastases. Although its specific biochemical role in these processes has yet to be delineated, considerable evidence suggests the phosphatase activity of PRL-1 is required for promoting cancer and metastasis. PRL-1 belongs to the protein tyrosine phosphatase (PTPase) family and functions using the CX5R consensus active site motif. Like other PTPases, PRL-1 is inhibited by oxidation at its active site Cys, however, disulfide bond formation occurs unusually readily in wild-type PRL-1. Chemical shift assignments are available for oxidized wild type, but numerous, substantial changes are observed in the spectra upon reduction. Because the reduced form is active, we sought to identify a stable mutant that would resist oxidation and be useful for facilitating drug screening and development using NMR-based assays. We present here NMR assignments for a full-length, reduced and active form of PRL-1, PRL-1-C170S-C171S, that is well suited for this purpose. PMID:19636948

  12. High-Throughput Spheroid Screens Using Volume, Resazurin Reduction, and Acid Phosphatase Activity.

    Science.gov (United States)

    Ivanov, Delyan P; Grabowska, Anna M; Garnett, Martin C

    2017-01-01

    Mainstream adoption of physiologically relevant three-dimensional models has been slow in the last 50 years due to long, manual protocols with poor reproducibility, high price, and closed commercial platforms. This chapter describes high-throughput, low-cost, open methods for spheroid viability assessment which use readily available reagents and open-source software to analyze spheroid volume, metabolism, and enzymatic activity. We provide two ImageJ macros for automated spheroid size determination-for both single images and images in stacks. We also share an Excel template spreadsheet allowing users to rapidly process spheroid size data, analyze plate uniformity (such as edge effects and systematic seeding errors), detect outliers, and calculate dose-response. The methods would be useful to researchers in preclinical and translational research planning to move away from simplistic monolayer studies and explore 3D spheroid screens for drug safety and efficacy without substantial investment in money or time.

  13. α-Glucosidase and Protein Tyrosine Phosphatase 1B Inhibitory Activity of Plastoquinones from Marine Brown Alga Sargassum serratifolium

    Directory of Open Access Journals (Sweden)

    Md. Yousof Ali

    2017-12-01

    Full Text Available Sargassum serratifolium C. Agardh (Phaeophyceae, Fucales is a marine brown alga that belongs to the family Sargassaceae. It is widely distributed throughout coastal areas of Korea and Japan. S. serratifolium has been found to contain high concentrations of plastoquinones, which have strong anti-cancer, anti-inflammatory, antioxidant, and neuroprotective activity. This study aims to investigate the anti-diabetic activity of S. serratifolium and its major constituents through inhibition of protein tyrosine phosphatase 1B (PTP1B, α-glucosidase, and ONOO−-mediated albumin nitration. S. serratifolium ethanolic extract and fractions exhibited broad PTP1B and α-glucosidase inhibitory activity (IC50, 1.83~7.04 and 3.16~24.16 µg/mL for PTP1B and α-glucosidase, respectively. In an attempt to identify bioactive compounds, three plastoquinones (sargahydroquinoic acid, sargachromenol and sargaquinoic acid were isolated from the active n-hexane fraction of S. serratifolium. All three plastoquinones exhibited dose-dependent inhibitory activity against PTP1B in the IC50 range of 5.14–14.15 µM, while sargachromenol and sargaquinoic acid showed dose-dependent inhibitory activity against α-glucosidase (IC50 42.41 ± 3.09 and 96.17 ± 3.48 µM, respectively. In the kinetic study of PTP1B enzyme inhibition, sargahydroquinoic acid and sargaquinoic acid led to mixed-type inhibition, whereas sargachromenol displayed noncompetitive-type inhibition. Moreover, plastoquinones dose-dependently inhibited ONOO−-mediated albumin nitration. Docking simulations of these plastoquinones demonstrated negative binding energies and close proximity to residues in the binding pocket of PTP1B and α-glucosidase, indicating that these plastoquinones have high affinity and tight binding capacity towards the active site of the enzymes. These results demonstrate that S. serratifolium and its major plastoquinones may have the potential as functional food ingredients for the

  14. Opening the conformation is a master switch for the dual localization and phosphatase activity of PTEN

    Science.gov (United States)

    Nguyen, Hoai-Nghia; Yang, Jr-Ming; Miyamoto, Takafumi; Itoh, Kie; Rho, Elmer; Zhang, Qiang; Inoue, Takanari; Devreotes, Peter N.; Sesaki, Hiromi; Iijima, Miho

    2015-01-01

    Tumor suppressor PTEN mainly functions at two subcellular locations, the plasma membrane and the nucleus. At the plasma membrane, PTEN dephosphorylates the tumorigenic second messenger PIP3, which drives cell proliferation and migration. In the nucleus, PTEN controls DNA repair and genome stability independently of PIP3. Whereas the concept that a conformational change regulates protein function through post-translational modifications has been well established in biology, it is unknown whether a conformational change simultaneously controls dual subcellular localizations of proteins. Here, we discovered that opening the conformation of PTEN is the crucial upstream event that determines its key dual localizations of this crucial tumor suppressor. We identify a critical conformational switch that regulates PTEN’s localization. Most PTEN molecules are held in the cytosol in a closed conformation by intramolecular interactions between the C-terminal tail and core region. Dephosphorylation of the tail opens the conformation and exposes the membrane-binding regulatory interface in the core region, recruiting PTEN to the membrane. Moreover, a lysine at residue 13 is also exposed and when ubiquitinated, transports PTEN to the nucleus. Thus, opening the conformation of PTEN is a key mechanism that enhances its dual localization and enzymatic activity, providing a potential therapeutic strategy in cancer treatments. PMID:26216063

  15. Active Free Surface Density Maps

    Science.gov (United States)

    Çelen, S.

    2016-10-01

    Percolation problems were occupied to many physical problems after their establishment in 1957 by Broadbent and Hammersley. They can be used to solve complex systems such as bone remodeling. Volume fraction method was adopted to set some algorithms in the literature. However, different rate of osteoporosis could be observed for different microstructures which have the same mass density, mechanical stimuli, hormonal stimuli and nutrition. Thus it was emphasized that the bone might have identical porosity with different specific surfaces. Active free surface density of bone refers the used total area for its effective free surface. The purpose of this manuscript is to consolidate a mathematical approach which can be called as “active free surface density maps” for different surface patterns and derive their formulations. Active free surface density ratios were calculated for different Archimedean lattice models according to Helmholtz free energy and they were compared with their site and bond percolation thresholds from the background studies to derive their potential probability for bone remodeling.

  16. Increased liver alkaline phosphatase and aminotransferase ...

    African Journals Online (AJOL)

    The effect of daily, oral administration of ethanolic extract of Khaya senegalensis stem bark (2mg/kg body weight) for 18days on the alkaline phosphatase, aspartate and alanine aminotransferase activities of rat liver and serum were investigated. Compared with the control, the activities of liver alkaline phosphatase (ALP), ...

  17. An evaluation on the activity level of Aspartate aminotransferase and Alkaline phosphatase nzymes in peri-implant sulcus fluid

    Directory of Open Access Journals (Sweden)

    Paknegad M. Assistant Professor

    2003-07-01

    Full Text Available Statement of Problem: The correlation between the activity of aspartate aminotransferase (AST and alkaline phosphatase (ALP enzymes in gingival sulcular fluid (GCF with inflammation and periodontal attachment loss has been proved, however there are not adequate studies about dental implants. Purpose: The aim of present study was to investigate the presence and activity level of AST & ALP and their correlation with pocket depth (PD and bleeding of peri-implant slcular fluid (PISF, and to evaluate the possibility of using these assessments as a diagnostic index in oral implantology. Material and Methods: In this study, 41 implants as test group and 41 contralateral teeth as control group, in 21 patients were evaluated. At first visit, the general information about implants and the values of pocket probing depth (PPD, modified sulcus bleeding index (mSBl and modified plaque index (mPI were recorded. At the second visit, samples of GCF/PISF were collected. AST & ALP activity was determined spectrophotometrically and data were analyzed by "t", "Mann-Whitney" tests and Pearson Spearman correlation coefficient."nResults: The results showed that there was a significant difference in the activity of AST between two study groups (P<0.0001. The average activity of ALP in test group was more than control group but the difference was not significant. After elimination of the confounding variables, the average AST in test group was 54.6 (S£=2.3 and in control groups was 44.8 (SE=2.3 (P=0.004. The average ALP in test group (SE=2.2 and in control (SE=2.2 were 36.6 and 35.4, respectively. Values of AST and ALP were positively correlated with other clinical parameters such as PD and mSBI which was significant in test group."nConclusion: The present study suggests that PISF analysis could be considered as a proper diagnostic strategy in the evaluation of dental implant success.

  18. Detection of Ca2+-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin

    Directory of Open Access Journals (Sweden)

    Tigran R Petrosyan

    2016-01-01

    Full Text Available The study aims to confirm the neuroregenerative effects of bacterial melanin (BM on central nervous system injury using a special staining method based on the detection of Ca2+-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex (group I; n = 12 or unilateral rubrospinal tract transection at the cervical level (C3–4 (group II; n = 12. In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution (BM subgroup and the remaining six rats were intramuscularly injected with saline (saline subgroup. Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca2+-dependent acid phosphatase activity detection in combination with Chilingarian's calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca2+-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system.

  19. Mitogen activated protein kinase phosphatase-1 prevents the development of tactile sensitivity in a rodent model of neuropathic pain

    Directory of Open Access Journals (Sweden)

    Ndong Christian

    2012-04-01

    Full Text Available Abstract Background Neuropathic pain due to nerve injury is one of the most difficult types of pain to treat. Following peripheral nerve injury, neuronal and glial plastic changes contribute to central sensitization and perpetuation of mechanical hypersensitivity in rodents. The mitogen activated protein kinase (MAPK family is pivotal in this spinal cord plasticity. MAPK phosphatases (MKPs limit inflammatory processes by dephosphorylating MAPKs. For example, MKP-1 preferentially dephosphorylates p-p38. Since spinal p-p38 is pivotal for the development of chronic hypersensitivity in rodent models of pain, and p-p38 inhibitors have shown clinical potential in acute and chronic pain patients, we hypothesize that induction of spinal MKP-1 will prevent the development of peripheral nerve-injury-induced hypersensitivity and p-p38 overexpression. Results We cloned rat spinal cord MKP-1 and optimize MKP-1 cDNA in vitro using transfections to BV-2 cells. We observed that in vitro overexpression of MKP-1 blocked lipopolysaccharide-induced phosphorylation of p38 (and other MAPKs as well as release of pro-algesic effectors (i.e., cytokines, chemokines, nitric oxide. Using this cDNA MKP-1 and a non-viral, in vivo nanoparticle transfection approach, we found that spinal cord overexpression of MKP-1 prevented development of peripheral nerve-injury-induced tactile hypersensitivity and reduced pro-inflammatory cytokines and chemokines and the phosphorylated form of p38. Conclusions Our results indicate that MKP-1, the natural regulator of p-p38, mediates resolution of the spinal cord pro-inflammatory milieu induced by peripheral nerve injury, resulting in prevention of chronic mechanical hypersensitivity. We propose that MKP-1 is a potential therapeutic target for pain treatment or prevention.

  20. Effects of Dihydroartemisinin and Artemether on the Growth, Chlorophyll Fluorescence, and Extracellular Alkaline Phosphatase Activity of the Cyanobacterium Microcystis aeruginosa.

    Directory of Open Access Journals (Sweden)

    Shoubing Wang

    Full Text Available Increased eutrophication in the recent years has resulted in considerable research focus on identification of methods for preventing cyanobacterial blooms that are rapid and efficient. The objectives of this study were to investigate the effects of dihydroartemisinin and artemether on the growth of Microcystis aeruginosa and to elucidate its mode of action. Variations in cell density, chlorophyll a, soluble protein, malondialdehyde, extracellular alkaline phosphatase activity (APA, and chlorophyll fluorescence parameters (Fv/Fm, ΦPSII, ETR, rapid light curves, fast chlorophyll fluorescence curves on fluorescence intensity, and relative variable fluorescence were evaluated by lab-cultured experiments. Our results demonstrated that both dihydroartemisinin and artemether inhibited the growth of M.aeruginosa by impairing the photosynthetic center in photosystem II and reducing extracellular APA, with a higher sensitivity exhibited toward artemether. The inhibitory effects of dihydroartemisinin on M.aeruginosa increased with concentration, and the maximum growth inhibitory rate was 42.17% at 24 mg·L-1 after 120h exposure, whereas it was 55.72% at 6 mg·L-1 artemetherafter 120h exposure. Moreover, the chlorophyll fluorescence was significantly inhibited (p<0.05 after 120h exposure to 12 and 24 mg·L-1 dihydroartemisinin. Furthermore, after 120h exposure to 6 mg·L-1 artemether, Fv/Fm, ΦPSII, ETR and rETRmax showed a significant decrease (p<0.01 from initial values of 0.490, 0.516, 17.333, and 104.800, respectively, to 0. One-way analysis of variance showed that 6 mg·L-1 artemether and 24 mg·L-1 dihydroartemisinin had significant inhibitory effects on extracellular APA (p<0.01. The results of this study would be useful to further studies to validate the feasibility of dihydroartemisinin and artemether treatment to inhibit overall cyanobacterial growth in water bodies, before this can be put into practice.

  1. Notch1 receptor regulates AKT protein activation loop (Thr308) dephosphorylation through modulation of the PP2A phosphatase in phosphatase and tensin homolog (PTEN)-null T-cell acute lymphoblastic leukemia cells.

    Science.gov (United States)

    Hales, Eric C; Orr, Steven M; Larson Gedman, Amanda; Taub, Jeffrey W; Matherly, Larry H

    2013-08-02

    Notch1 activating mutations occur in more than 50% of T-cell acute lymphoblastic leukemia (T-ALL) cases and increase expression of Notch1 target genes, some of which activate AKT. HES1 transcriptionally silences phosphatase and tensin homolog (PTEN), resulting in AKT activation, which is reversed by Notch1 inhibition with γ-secretase inhibitors (GSIs). Mutational loss of PTEN is frequent in T-ALL and promotes resistance to GSIs due to AKT activation. GSI treatments increased AKT-Thr(308) phosphorylation and signaling in PTEN-deficient, GSI-resistant T-ALL cell lines (Jurkat, CCRF-CEM, and MOLT3), suggesting that Notch1 represses AKT independent of its PTEN transcriptional effects. AKT-Thr(308) phosphorylation and downstream signaling were also increased by knocking down Notch1 in Jurkat (N1KD) cells. This was blocked by treatment with the AKT inhibitor perifosine. The PI3K inhibitor wortmannin and the protein phosphatase type 2A (PP2A) inhibitor okadaic acid both impacted AKT-Thr(308) phosphorylation to a greater extent in nontargeted control than N1KD cells, suggesting decreased dephosphorylation of AKT-Thr(308) by PP2A in the latter. Phosphorylations of AMP-activated protein kinaseα (AMPKα)-Thr(172) and p70S6K-Thr(389), both PP2A substrates, were also increased in both N1KD and GSI-treated cells and responded to okadaic acid treatment. A transcriptional regulatory mechanism was implied because ectopic expression of dominant-negative mastermind-like protein 1 increased and wild-type HES1 decreased phosphorylation of these PP2A targets. This was independent of changes in PP2A subunit levels or in vitro PP2A activity, but was accompanied by decreased association of PP2A with AKT in N1KD cells. These results suggest that Notch1 can regulate PP2A dephosphorylation of critical cellular regulators including AKT, AMPKα, and p70S6K.

  2. Differentiation-dependent activation of the human intestinal alkaline phosphatase promoter by HNF-4 in intestinal cells

    DEFF Research Database (Denmark)

    Olsen, Line; Bressendorff, Simon; Troelsen, Jesper T

    2005-01-01

    The intestinal alkaline phosphatase gene (ALPI) encodes a digestive brush-border enzyme, which is highly upregulated during small intestinal epithelial cell differentiation. To identify new putative promoter motifs responsible for the regulation of ALPI expression during differentiation of the en...

  3. Evidence for the absence of cerebral glucose-6-phosphatase activity in glycogen storage disease type I (Von Gierke's disease)

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, M.E.; Mazziotta, J.C.; Hawkins, R.A.; Philippart, M.

    1981-01-01

    Glycogen storage disease type I (GSD-I) is characterized by a functional deficit in glucose-6-phosphatase that normally hydrolyzes glucose-6-PO/sub 4/ to glucose. This enzyme is primarily found in liver, kidney, and muscle but it is also present in brain, where it appears to participate in the regulation of cerebral tissue glucose. Since most neurological symptoms in GSD-I patients involve systemic hypoglycemia, previous reports have not examined possible deficiencies in phosphatase activity in the brain. Positron computed tomography, F-18-labeled 2-fluorodeoxyglucose (FDG) and a tracer kinetic model for FDG were used to measure the cortical plasma/tissue forward and reverse transport, phosphorylation and dephosphorylation rate constants, tissue/plasma concentration gradient, tissue concentration turnover rate for this competitive analog of glucose, and the cortical metabolic rates for glucose. Studies were carried out in age-matched normals (N = 13) and a single GSD-I patient. The dephosphorylation rate constant in the GSD-I patient was about one tenth the normal value indicating a low level of cerebral phosphatase activity. The other measured parameters were within normal limits except for the rate of glucose phosphorylation which reflected a cortical glucose metabolic rate one half the normal value. Since glucose transport and tissue glucose concentration was normal, the reduced cortical glucose metabolism probably results from the use of alternative substrates (..beta..-hydroxybutyrate and acetoacetate) which are consistently elevated in the plasma of GSD-I patients.

  4. Placental alkaline phosphatase activity and its relation to foetal growth and nutrition in appropriate and small for gestational age newborns at term.

    Science.gov (United States)

    Mosbah, Amira A Abd El-Rahman; Abd-Ellatif, Nahla A Bahgat; Sorour, Ehab Ibrahim; El-Halaby, Alaa F

    2011-12-01

    The placental alkaline phosphatase (PAP) activity progressively rises as pregnancy advances, possibly, because of its increasing synthesis by placental tissue. The present study examined the relationship between placental alkaline phosphatase activity and the biochemical indices of foetal nutrition (cord blood glucose, albumin) and growth (neonatal birth weight). Placental and umbilical cord blood samples were collected from 56 term deliveries 30 of them were appropriate for gestational age (AGA) and 26 were small for gestational age(SGA) and prepared for placental alkaline phosphatase assay, glucose and albumin estimations using standard procedures. The birth weights of the neonates at term were taken and recorded. Correlation analyses of the data obtained show significant positive relationships between PAP and cord blood glucose, albumin and birth weight in AGA newborn (r2 = 0.86, 0.71, 0.68 p<0.05) and (r2 = 0.69, 0.81, 0.73 p<0.05) in SGA newborn but no significant relationship with gestational age, also there was significant statistical difference between both groups in level of PAP, glucose and albumin.

  5. EFEITO DE FATORES AMBIENTAIS DA FOSFATASE ÁCIDA NO FEIJOEIRO EFFECTS OF ENVIRONMENTAL FACTORS ON THE ACTIVITY OF ACID PHOSPHATASE IN COMMON BEAN

    Directory of Open Access Journals (Sweden)

    José Renato de Freitas

    2007-09-01

    Full Text Available

    Plantas com 15 dias após a germinação foram colhidas em experimentos de campo com a finalidade de conhecer o pH, temperatura e tempo necessários para melhor expressar a atividade da fosfatase ácida em três variedades do feijoeiro (Phaseolus vulgaris L., Carioca, EMP-84 e CNF-l0, na presença e na ausência de fósforo. Os maiores valores de atividade da fosfatase ácida foram observadas quando as plantas foram colocadas em solução em pH 5,5 durante 120 minutos à temperatura de 30°C. A utilização de substâncias tamponantes como PNPP + Triton X-100 expressaram melhor a atividade da fosfatase ácida. As condições de vácuo constituíram um fator positivo para a atividade da fosfatase ácida. As plantas desenvolvidas sob estresse hídrico apresentaram menor atividade da fosfatase ácida. A relação folha-raiz da atividade da fosfatase ácida atingiu 5,72 para a variedade Carioca, 4,91 para a variedade EMP-84 e 4,36 para a variedade CNF-10.

    PALAVRAS-CHAVE: pH; temperatura; solução tamponada; tempo de reação; Phaseolus vulgaris.

    Plants with 15 days after the germination were picked in field experiments with the purpose of knowing the best pH, temperature and the necessary time to express the activity of the phosphatase acid in three bean varieties (Phaseolus vulgaris L., Carioca, EMP-84 and CNF-10, in the presence and in the phosphorus absence. The largest values of activity of the phosphatase acid were observed when the plants were tested in pH 5.5 solution during 120 minutes at the temperature of 30°C. The use of buffer substances as PNPP + Triton X-100 expressed better the activity of the phosphatase acid. The vacuum condition constituted a positive factor to express the activity of the phosphatase acid. The plants

  6. Presence and patterns of alkaline phosphatase activity and phosphorus cycling in natural riparian zones under changing nutrient conditions

    Directory of Open Access Journals (Sweden)

    Peifang Wang

    2014-08-01

    Full Text Available Phosphorus (P is an important limiting nutrient in aquatic ecosystems and knowledge of P cycling is fundamental for reducing harmful algae blooms and other negative effects in water. Despite their importance, the characteristics of P cycling under changing nutrient conditions in shallow lakes were poorly investigated. In this study, in situ incubation experiments were conducted in a natural riparian zone in the main diversion channel used for water transfer into Lake Taihu (Wangyu River. Variations in microbial biomass, dissolved P fractions (organic and inorganic, and alkaline phosphatase activity (bulk APA and specific APA were determined after incubation with and without the addition of P and nitrogen (N (4 total water treatments: +P, +N, +NP, and control. Experiments were conducted during two seasons (late spring and early fall to account for natural differences in nutrient levels that may occur in situ. Our results demonstrated that low levels of DRP may not necessarily indicate P limitation. Phytoplankton exhibited “serial N limitation with P stress” in May, such that chlorophyll a (Chl a increased significantly with N addition, while the limiting nutrient shifted to P in October and phytoplankton biomass increased with P addition. Phytoplankton contributed greatly to APA production and was significantly influenced by P bioavailability, yet high levels of bulk APA were also not necessarily indicative of P limitation. In contrast to phytoplankton, bacteria were less P stressed. As a consequence of enhanced utilization of dissolved reactive P (DRP and dissolved organic P (DOP, +N treatment elevated APA significantly. By contrast, APA could be repressed to low values and phytoplankton converted a large portion of DRP to DOP with P addition. But this was not consistent with bacteria APA (bact-APA in the absence or presence of abundant phytoplankton biomass. The correlation between bulk APA and DRP was good at separate sites and discrepant

  7. Voltage sensitive phosphatases: emerging kinship to protein tyrosine phosphatases from structure-function research

    Directory of Open Access Journals (Sweden)

    Kirstin eHobiger

    2015-02-01

    Full Text Available The transmembrane protein Ci-VSP from the ascidian Ciona intestinalis was described as first member of a fascinating family of enzymes, the voltage sensitive phosphatases (VSPs. Ci-VSP and its voltage-activated homologs from other species are stimulated by positive membrane potentials and dephosphorylate the head groups of negatively charged phosphoinositide phosphates (PIPs. In doing so, VSPs act as control centers at the cytosolic membrane surface, because they intervene in signaling cascades that are mediated by PIP lipids. The characteristic motif CX5RT/S in the active site classifies VSPs as members of the huge family of cysteine-based protein tyrosine phosphatases (PTPs. Although PTPs have already been well characterized regarding both, structure and function, their relationship to VSPs has drawn only limited attention so far. Therefore, the intention of this review is to give a short overview about the extensive knowledge about PTPs in relation to the facts known about VSPs. Here, we concentrate on the structural features of the catalytic domain which are similar between both classes of phosphatases and their consequences for the enzymatic function. By discussing results obtained from crystal structures, molecular dynamics simulations, and mutagenesis studies, a possible mechanism for the catalytic cycle of VSPs is presented based on that one proposed for PTPs. In this way, we want to link the knowledge about the catalytic activity of VSPs and PTPs.

  8. Alkaline Phosphatases From Camel Small Intestine | Fahmy ...

    African Journals Online (AJOL)

    Camel intestinal alkaline phosphatase have been purified and characterized. The purification was carried out by chromatography on DEAE-cellulose. Five intestinal alkaline phosphatase isoenzymes (IAP1 to IAP5) were obtained. IAP2 and IAP5 with the highest activity levels were purified to homogeneity by Sephacryl ...

  9. Localization of some phosphatases in yeast

    NARCIS (Netherlands)

    Tonino, G.J.M.; Steyn-Parvé, Elizabeth P.

    1963-01-01

    1. 1. The localization of some phosphatases has been studied in yeast cells that were either fragmented by shaking intact cells with glass beads or by hypotonic or isotonic disruption of protoplasts prepared from intact cells. 2. 2. The non-specific acid phosphatase with optimum activity at pH

  10. Hematopoietic cell phosphatase is recruited to CD22 following B cell antigen receptor ligation

    NARCIS (Netherlands)

    Lankester, A. C.; van Schijndel, G. M.; van Lier, R. A.

    1995-01-01

    Hematopoietic cell phosphatase is a nonreceptor protein tyrosine phosphatase that is preferentially expressed in hematopoietic cell lineages. Motheaten mice, which are devoid of (functional) hematopoietic cell phosphatase, have severe disturbances in the regulation of B cell activation and

  11. Hydroxamic acid surface active agents

    Directory of Open Access Journals (Sweden)

    El-Sawy, A. A.

    2001-10-01

    Full Text Available p-Hydroxy phenyloctadecanol and p-hydroxy phenyloctadecanoic acid were used as new precursors for the preparation of surface active hydroxamic acid including different moles of propylene oxide. The hydroxamic acid was prepared by the reaction of propenoxylated products with sodium chloroacetate, followed by methyl esterification and the resultant product reacted with hydroxyl amine hydrochloride to give the hydroxamic acid. The structures of prepared hydroxamic acid were confirmed by spectroscopic study. The surface activity of prepared hydroxamic acid was studied; the results revealed that, the prepared hydroxamic acid has pronounced surface activity, the alcohol substrate shows a surface activity superior than the acid substrate.Se han utilizado el p-hidroxifeniloctadecanol y el ácido p-hidroxifeniloctadecanoico como nuevos precursores para la preparación de tensioactivos derivados del ácido hidroxámico, que incluyen diferentes moles de óxido de propileno. El ácido hidroxámico se preparó por reacción de los productos propenoxilados con cloroacetato sódico, seguido de la formación de ésteres metílicos, y los productos resultantes se hicieron reaccionar con clorhidrato de hidroxilamina para dar los derivados del ácido hidroxámico. Las estructuras de los derivados preparados del ácido hidroxámico, se confirmaron por técnicas espectroscópicas, estudiándose su actividad superficial cuyos resultados mostraron que dichos compuestos tenían un alto valor. La actividad superficial del sustrato alcohólico fue mayor que la del sustrato ácido.

  12. Structural Insight into the Critical Role of the N-Terminal Region in the Catalytic Activity of Dual-Specificity Phosphatase 26.

    Directory of Open Access Journals (Sweden)

    Eun-Young Won

    Full Text Available Human dual-specificity phosphatase 26 (DUSP26 is a novel target for anticancer therapy because its dephosphorylation of the p53 tumor suppressor regulates the apoptosis of cancer cells. DUSP26 inhibition results in neuroblastoma cell cytotoxicity through p53-mediated apoptosis. Despite the previous structural studies of DUSP26 catalytic domain (residues 61-211, DUSP26-C, the high-resolution structure of its catalytically active form has not been resolved. In this study, we determined the crystal structure of a catalytically active form of DUSP26 (residues 39-211, DUSP26-N with an additional N-terminal region at 2.0 Å resolution. Unlike the C-terminal domain-swapped dimeric structure of DUSP26-C, the DUSP26-N (C152S monomer adopts a fold-back conformation of the C-terminal α8-helix and has an additional α1-helix in the N-terminal region. Consistent with the canonically active conformation of its protein tyrosine phosphate-binding loop (PTP loop observed in the structure, the phosphatase assay results demonstrated that DUSP26-N has significantly higher catalytic activity than DUSP26-C. Furthermore, size exclusion chromatography-multiangle laser scattering (SEC-MALS measurements showed that DUSP26-N (C152S exists as a monomer in solution. Notably, the crystal structure of DUSP26-N (C152S revealed that the N-terminal region of DUSP26-N (C152S serves a scaffolding role by positioning the surrounding α7-α8 loop for interaction with the PTP-loop through formation of an extensive hydrogen bond network, which seems to be critical in making the PTP-loop conformation competent for phosphatase activity. Our study provides the first high-resolution structure of a catalytically active form of DUSP26, which will contribute to the structure-based rational design of novel DUSP26-targeting anticancer therapeutics.

  13. Receptor protein tyrosine phosphatase alpha activates Src-family kinases and controls integrin-mediated responses in fibroblasts

    DEFF Research Database (Denmark)

    Su, J; Muranjan, M; Sap, J

    1999-01-01

    BACKGROUND: Fyn and c-Src are two of the most widely expressed Src-family kinases. Both are strongly implicated in the control of cytoskeletal organization and in the generation of integrin-dependent signalling responses in fibroblasts. These proteins are representative of a large family of tyros......BACKGROUND: Fyn and c-Src are two of the most widely expressed Src-family kinases. Both are strongly implicated in the control of cytoskeletal organization and in the generation of integrin-dependent signalling responses in fibroblasts. These proteins are representative of a large family...... established, no corresponding phosphatases have been identified that, under physiological conditions, function as positive regulators of c-Src and Fyn in fibroblasts. RESULTS: Receptor protein tyrosine phosphatase alpha (RPTPalpha) was inactivated by homologous recombination. Fibroblasts derived from...

  14. Joint influence of temperature and ions of metals on level of activity alkaline phosphatase the mucous membrane of intestines beluga, the starlet and their hybrid

    Directory of Open Access Journals (Sweden)

    D. A. Bednyakov

    2010-01-01

    Full Text Available In work joint influence of ions of bivalent metals (Mn, Fe, Co, Ni, Cu and Zn and temperatures on level of activity alkaline phosphatase mucous membrane beluga, starlet and their hybrid is shown. Dependence of response of enzyme on action of ions of metals according to their position in a periodic table of chemical elements is shown. The given dependence remains and at temperature change incubation, only at low temperatures the activating effect of metals being in the period beginning is maximum, and at high, is maximum inhibiting effect of metals being in the period end.

  15. Active β-catenin is regulated by the PTEN/PI3 kinase pathway: a role for protein phosphatase PP2A.

    Science.gov (United States)

    Persad, Amit; Venkateswaran, Geetha; Hao, Li; Garcia, Maria E; Yoon, Jenny; Sidhu, Jaskiran; Persad, Sujata

    2016-11-01

    Dysregulation of Wnt/β-catenin signaling has been associated with the development and progression of many cancers. The stability and subcellular localization of β-catenin, a dual functional protein that plays a role in intracellular adhesion and in regulating gene expression, is tightly regulated. However, little is known about the transcriptionally active form of β-catenin, Active Beta Catenin (ABC), that is unphosphorylated at serine 37 (Ser37) and threonine 41 (Thr41). Elucidating the mechanism by which β-catenin is activated to generate ABC is vital to the development of therapeutic strategies to block β-catenin signaling for cancer treatment. Using melanoma, breast and prostate cancer cell lines, we show that while cellular β-catenin levels are regulated by the Wnt pathway, cellular ABC levels are mainly regulated by the PI3K pathway and are dependent on the phosphatase activity of the protein phosphatase PP2A. Furthermore, we demonstrate that although the PI3K/PTEN pathway does not regulate total β-catenin protein levels within the cell, it plays a role in regulating the subcellular localization of β-catenin. Our results support a novel functional interaction/cross-talk between the PTEN/PI3K and Wnt pathways in the regulation of the subcellular/nuclear levels of ABC, which is crucially important for the protein's activity as a transcription factor and its biological effects in health and disease.

  16. MicroRNA-1 and -133 increase arrhythmogenesis in heart failure by dissociating phosphatase activity from RyR2 complex.

    Directory of Open Access Journals (Sweden)

    Andriy E Belevych

    Full Text Available In heart failure (HF, arrhythmogenic spontaneous sarcoplasmic reticulum (SR Ca(2+ release and afterdepolarizations in cardiac myocytes have been linked to abnormally high activity of ryanodine receptors (RyR2s associated with enhanced phosphorylation of the channel. However, the specific molecular mechanisms underlying RyR2 hyperphosphorylation in HF remain poorly understood. The objective of the current study was to test the hypothesis that the enhanced expression of muscle-specific microRNAs (miRNAs underlies the HF-related alterations in RyR2 phosphorylation in ventricular myocytes by targeting phosphatase activity localized to the RyR2. We studied hearts isolated from canines with chronic HF exhibiting increased left ventricular (LV dimensions and decreased LV contractility. qRT-PCR revealed that the levels of miR-1 and miR-133, the most abundant muscle-specific miRNAs, were significantly increased in HF myocytes compared with controls (2- and 1.6-fold, respectively. Western blot analyses demonstrated that expression levels of the protein phosphatase 2A (PP2A catalytic and regulatory subunits, which are putative targets of miR-133 and miR-1, were decreased in HF cells. PP2A catalytic subunit mRNAs were validated as targets of miR-133 by using luciferase reporter assays. Pharmacological inhibition of phosphatase activity increased the frequency of diastolic Ca(2+ waves and afterdepolarizations in control myocytes. The decreased PP2A activity observed in HF was accompanied by enhanced Ca(2+/calmodulin-dependent protein kinase (CaMKII-mediated phosphorylation of RyR2 at sites Ser-2814 and Ser-2030 and increased frequency of diastolic Ca(2+ waves and afterdepolarizations in HF myocytes compared with controls. In HF myocytes, CaMKII inhibitory peptide normalized the frequency of pro-arrhythmic spontaneous diastolic Ca(2+ waves. These findings suggest that altered levels of major muscle-specific miRNAs contribute to abnormal RyR2 function in HF by

  17. Assessment and kinetics of soil phosphatase in Brazilian Savanna systems

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    ADÃO S. FERREIRA

    2016-06-01

    Full Text Available The activity and kinetics of soil phosphatases are important indicators to evaluate soil quality in specific sites such as the Cerrado (Brazilian Savanna. This study aimed to determine the activity and kinetic parameters of soil phosphatase in Cerrado systems. Soil phosphatase activity was assessed in samples of native Cerrado (NC, no-tillage (NT, conventional tillage (CT and pasture with Brachiaria brizantha (PBb and evaluated with acetate buffer (AB, tris-HCl buffer (TB, modified universal buffer (MUB and low MUB. The Michaelis-Menten equation and Eadie-Hofstee model were applied to obtain the kinetic parameters of soil phosphatase using different concentrations of p-nitrophenol phosphate (p-NPP. MUB showed the lowest soil phosphatase activity in all soils whereas AB in NC and NT presented the highest. Low MUB decreased interferences in the assessment of soil phosphatase activity when compared to MUB, suggesting that organic acids interfere on the soil phosphatase activity. In NC and NT, soil phosphatase activity performed with TB was similar to AB and low MUB. Km values from the Michaels-Menten equation were higher in NC than in NT, which indicate a lower affinity of phosphatase activity for the substrate in NC. Vmax values were also higher in NC than in NT. The Eadie-Hofstee model suggests that NC had more phosphatase isoforms than NT. The study showed that buffer type is of fundamental importance when assessing soil phosphatase activity in Cerrado soils.

  18. Effects of dietary vitamin E on mucosal maltase and alkaline phosphatase enzyme activities and on the amount of mucosal malonyldialdehyde in broiler chickens

    OpenAIRE

    Seyed Hamid Farrokhifar; Ramezan Ali Jafari; Naeem Erfani Majd; Seyed Reza Fatemi Tabatabaee; Mansour Mayahi

    2014-01-01

    The effects of dietary vitamin E levels on mucosal maltase and alkaline phosphatase (ALP) enzyme activities and on the amount of mucosal malonyldialdehyde (MDA) in broiler chickens were studied in the present study. One hundred and eighty of male day old broiler chicks (Ross 308 strain) were randomly assigned into five groups, each with three replicates and 12 chicks in each replicate. Chickens in group A were fed corn-soy- based diet, while those in groups B, C, D and E were fed the same die...

  19. Phenylarsine Oxide Binding Reveals Redox-Active and Potential Regulatory Vicinal Thiols on the Catalytic Subunit of Protein Phosphatase 2A

    OpenAIRE

    Foley, Timothy D.; Melideo, Scott L.; Healey, Adriana E.; Lucas, Eugene J.; Koval, Jason A.

    2010-01-01

    Our earlier finding that the activity of protein phosphatase 2A from rat brain is inhibited by micromolar concentrations of the dithiol cross-linking reagent phenylarsine oxide (PAO) has encouraged the hypothesis that the catalytic subunit (PP2Ac) of PP2A contains one or more pairs of closely-spaced (vicinal) thiol pairs that may contribute to regulation of the enzyme. The results of the present study demonstrate using immobilized PAO-affinity chromatography that PP2Ac from rat brain formed s...

  20. Activation of c-Src and Fyn kinases by protein tyrosine phosphatase RPTPalpha is substrate-specific and compatible with lipid raft localization

    DEFF Research Database (Denmark)

    Vacaresse, Nathalie; Møller, Bente; Danielsen, Erik Michael

    2008-01-01

    Tyrosine kinases of the Src family (SFKs) function in multiple signaling pathways, raising the question of how appropriate regulation and substrate choice are achieved. SFK activity is modulated by several protein tyrosine phosphatases (PTPs), among which RPTPa and SHP2 are the best established. We...... studied how RPTPa affects substrate specificity and regulation of c-Src and Fyn in response to EGF and PDGF. We find that RPTPa, in a growth factor-specific manner, directs the specificity of these kinases towards a specific subset of SFK substrates, particularly the focal adhesion protein Paxillin...

  1. Tumor suppressor PTEN affects tau phosphorylation: deficiency in the phosphatase activity of PTEN increases aggregation of an FTDP-17 mutant Tau

    Directory of Open Access Journals (Sweden)

    Zhang Xue

    2006-07-01

    Full Text Available Abstract Background Aberrant hyperphosphorylation of tau protein has been implicated in a variety of neurodegenerative disorders. Although a number of protein kinases have been shown to phosphorylate tau in vitro and in vivo, the molecular mechanisms by which tau phosphorylation is regulated pathophysiologically are largely unknown. Recently, a growing body of evidence suggests a link between tau phosphorylation and PI3K signaling. In this study, phosphorylation, aggregation and binding to the microtubule of a mutant frontal temporal dementia and parkinsonism linked to chromosome 17 (FTDP-17 tau in the presence of tumor suppressor PTEN, a major regulatory component in PI3K signaling, were investigated. Results Phosphorylation of the human mutant FTDP-17 tau, T40RW, was evaluated using different phospho-tau specific antibodies in the presence of human wild-type or phosphatase activity null mutant PTEN. Among the evaluated phosphorylation sites, the levels of Ser214 and Thr212 phospho-tau proteins were significantly decreased in the presence of wild-type PTEN, and significantly increased when the phosphatase activity null mutant PTEN was ectopically expressed. Fractionation of the mutant tau transfected cells revealed a significantly increased level of soluble tau in cytosol when wild-type PTEN was expressed, and an elevated level of SDS-soluble tau aggregates in the presence of the mutant PTEN. In addition, the filter/trap assays detected more SDS-insoluble mutant tau aggregates in the cells overexpressing the mutant PTEN compared to those in the cells overexpressing wild-type PTEN and control DNA. This notion was confirmed by the immunocytochemical experiment which demonstrated that the overexpression of the phosphatase activity null mutant PTEN caused the mutant tau to form aggregates in the COS-7 cells. Conclusion Tumor suppressor PTEN can alleviate the phosporylation of the mutant FTDP-17 tau at specific sites, and the phosphatase activity

  2. Nonreceptor protein tyrosine and lipid phosphatases in type I Fcepsilon receptor-mediated activation of mast and basophils

    Czech Academy of Sciences Publication Activity Database

    Heneberg, Petr; Dráber, Petr

    2002-01-01

    Roč. 128, č. 4 (2002), s. 253-263 ISSN 1018-2438 R&D Projects: GA MŠk LN00A026; GA ČR GA204/00/0204; GA ČR GA310/00/0205; GA AV ČR IAA5052005; GA AV ČR IAA7052006 Institutional research plan: CEZ:AV0Z5052915 Keywords : phosphatases * tyrosin kinases * lipid phosphorylation Subject RIV: EC - Immunology Impact factor: 1.828, year: 2002

  3. Effects of Betaine Aldehyde Dehydrogenase-Transgenic Soybean on Phosphatase Activities and Rhizospheric Bacterial Community of the Saline-Alkali Soil

    Directory of Open Access Journals (Sweden)

    Ying Nie

    2016-01-01

    Full Text Available The development of transgenic soybean has produced numerous economic benefits; however the potential impact of root exudates upon soil ecological systems and rhizospheric soil microbial diversity has also received intensive attention. In the present study, the influence of saline-alkali tolerant transgenic soybean of betaine aldehyde dehydrogenase on bacterial community structure and soil phosphatase during growth stages was investigated. The results showed that, compared with nontransgenic soybean as a control, the rhizospheric soil pH of transgenic soybean significantly decreased at the seedling stage. Compared to HN35, organic P content was 13.5% and 25.4% greater at the pod-filling stage and maturity, respectively. The acid phosphatase activity of SRTS was significantly better than HN35 by 12.74% at seedling, 14.03% at flowering, and 59.29% at podding, while alkaline phosphatase achieved maximum activity in the flowering stage and was markedly lower than HN35 by 13.25% at pod-filling. The 454 pyrosequencing technique was employed to investigate bacterial diversity, with a total of 25,499 operational taxonomic units (OTUs obtained from the 10 samples. Notably, the effect of SRTS on microbial richness and diversity of rhizospheric soil was marked at the stage of podding and pod-filling. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla among all samples. Compared with HN35, the relative abundance of Proteobacteria was lower by 2.01%, 2.06%, and 5.28% at the stage of seedling, at pod-bearing, and at maturity. In genus level, the relative abundance of Gp6, Sphingomonas sp., and GP4 was significantly inhibited by SRTS at the stage of pod-bearing and pod-filling.

  4. Quantitative evaluation of the alkaline phosphatase activity in industrial and traditional dairy products supplied in Ahvaz as an indicator of pasteurization

    Directory of Open Access Journals (Sweden)

    M. Zarei

    2017-05-01

    Full Text Available Alkaline phosphatase is an indigenous milk enzyme and is probably, the most important indigenous milk enzyme from a dairy technology viewpoint which is used to determine the efficacy of the pasteurization process. The aim of this study was to assess the alkaline phosphatase activity of 200 samples of industrial and traditional yoghurt, ice cream and cheese, as well as raw and pasteurized milk samples. To achieve this purpose, p-nitrophenylphosphate was used as substrate and the amount of liberated p-nitrophenol was measured spectrophotometrically. The amount of liberated p-nitrophenol in all samples of raw milk was very high (6839±4070 µg/ml but in pasteurized milk samples, the amount was in the range of 0.75-52.96 µg/ml and 88% of the samples had less than 10 µg p-nitrophenol/ml, the maximum permissible limit of p-nitrophenol in pasteurized products. The amount of liberated p-nitrophenol was in the range of 5.68-1210 µg/ml and 2.61-18.22 µg/ml in traditional and industrial cheese samples, respectively and it was estimated at the range of 0.75-26.67 µg/ml and 0.71- 35.82 µg/ml for traditional and industrial ice cream samples, respectively. The lowest alkaline phosphatase activity was observed in both industrial and traditional yoghurt samples. Meanwhile, p-nitrophenol in 12% of industrial cheese, 44% of traditional cheese and 16% of both industrial and traditional ice cream samples was higher than 10 µg/ml which could be due to the inadequate pasteurization of the product or cross contamination with raw milk. The results of the present study showed a need for more strict attention in the pasteurization of milk and its products.

  5. An Experimental Insight into Extracellular Phosphatases – Differential Induction of Cell-Specific Activity in Green Algae Cultured under Various Phosphorus Conditions

    Directory of Open Access Journals (Sweden)

    Jaroslav Vrba

    2018-02-01

    Full Text Available Extracellular phosphatase activity (PA has been used as an overall indicator of P depletion in lake phytoplankton. However, detailed insights into the mechanisms of PA regulation are still limited, especially in the case of acid phosphatases. The novel substrate ELF97 phosphate allows for tagging PA on single cells in an epifluorescence microscope. This fluorescence-labeled enzyme activity (FLEA assay enables for autecological studies in natural phytoplankton and algal cultures. We combined the FLEA assay with image analysis to measure cell-specific acid PA in two closely related species of the genus Coccomyxa (Trebouxiophyceae, Chlorophyta isolated from two acidic lakes with distinct P availability. The strains were cultured in a mineral medium supplied with organic (beta-glycerol phosphate or inorganic (orthophosphate P at three concentrations. Both strains responded to experimental conditions in a similar way, suggesting that acid extracellular phosphatases were regulated irrespectively of the origin and history of the strains. We found an increase in cell-specific PA at low P concentration and the cultures grown with organic P produced significantly higher (ca. 10-fold PA than those cultured with the same concentrations of inorganic P. The cell-specific PA measured in the cultures grown with the lowest organic P concentration roughly corresponded to those of the original Coccomyxa population from an acidic lake with impaired P availability. The ability of Coccomyxa strains to produce extracellular phosphatases, together with tolerance for both low pH and metals can be one of the factors enabling the dominance of the genus in extreme conditions of acidic lakes. The analysis of frequency distribution of the single-cell PA documented that simple visual counting of ‘active’ (labeled and ‘non-active’ (non-labeled cells can lead to biased conclusions regarding algal P status because the actual PA of the ‘active’ cells can vary from

  6. Surface active monomers synthesis, properties, and application

    CERN Document Server

    Borzenkov, Mykola

    2014-01-01

    This brief includes information on the background?of and development of synthesis of various types of surface active monomers. The authors explain the importance of utilization of surface active monomers for creation of surface active polymers? and the various biomedical applications of such compounds . This brief introduces techniques for the synthesis of novel types of surface active monomers, their colloidal and polymerizable properties and application for needs of medicine and biology.

  7. Transplacental effects of thyrocalcitonin on intestinal calcium-binding protein, alkaline phosphatase activity and ossification of long bones in rat fetuses.

    Science.gov (United States)

    Peshin, J; Ornoy, A; Menczel, J

    1976-03-01

    Pregnant rats were treated with 44, 88 and 176 Medical Research Council munits of thyrocalcitonin (TCT) twice daily during days 10 to 21 of gestation. Nonpregnant rats received the same treatment for 12 days. Administration of TCT to the pregnant rats increased the ash and calcium content of fetal bones and decreased the phosphorus content. The diaphyses were short and contained many persisting enchondral trabeculae and a reduced number of osteoclasts. TCT reduced the fetal intestinal alkaline phosphatase activity but elevated the intestinal calcium-binding protein content. In the pregnant and nonpregnant rats, treatment with TCT resulted in hypocalcemia and hypophosphatemia, and increased the calcium-binding protein content of the duodenal mucosa. In the fetuses, the calcium-binding protein content and alkaline phosphatase activity were higher in the jejunum and ileum than in the duodenum, and were much higher than the values found in adult animals. Our findings indicate that TCT passes through the rat placenta and affects the fetal skeleton and calcium metabolism directly, resulting primarily in decreased bone resorption.

  8. Alkaline phosphatase activity and its relationship to inorganic phosphorus in the transition zone of the North-western African upwelling system

    Science.gov (United States)

    Sebastián, Marta; Arístegui, Javier; Montero, María F.; Escanez, Jose; Xavier Niell, F.

    2004-08-01

    The enzymatic activity of alkaline phosphatase (APA) was studied in the transition zone between the African upwelling system and the open ocean waters of the Canary Islands region. This region is recurrently dominated by the presence of upwelling filaments that may transport nutrient-enriched waters out into the open ocean before nutrients become exhausted by plankton. Turnover rates by APA were generally low in the whole region, but detectable in all the measurements carried out. On average, turnover rates were higher in the upwelling stations, and APA in those waters seemed to be mainly generated by heterotrophic bacteria to supply easily assimilable organic C. APA outside the upwelling area showed an inverse hyperbolic relationship with increasing phosphate, suggesting the presence of both constitutive and Pi-inducible APA. In these offshore waters, a threshold of 0.1 μM of phosphate could be defined for the regulatory function of Pi on APA. Thus, APA in nutrient-poor waters seemed to be induced to compensate for Pi-deficiency. Turnover rates in the filaments showed basal (probably constitutive) levels, whereas they increased in the surrounding waters, where phosphate concentration presumably did not satisfy plankton P-demands. The fertilising effect of the filaments and associated cyclonic eddies extended to at least 175 km offshore, where basal alkaline phosphatase activities were still found. The magnitude of this effect depends probably on the intensity of upwelling events and the degree of recirculation of filament water back to the coastal jet.

  9. Nicotine inhibits collagen synthesis and alkaline phosphatase activity, but stimulates DNA synthesis in osteoblast-like cells

    International Nuclear Information System (INIS)

    Ramp, W.K.; Lenz, L.G.; Galvin, R.J.

    1991-01-01

    Use of smokeless tobacco is associated with various oral lesions including periodontal damage and alveolar bone loss. This study was performed to test the effects of nicotine on bone-forming cells at concentrations that occur in the saliva of smokeless tobacco users. Confluent cultures of osteoblast-like cells isolated from chick embryo calvariae were incubated for 2 days with nicotine added to the culture medium (25-600 micrograms/ml). Nicotine inhibited alkaline phosphatase in the cell layer and released to the medium, whereas glycolysis (as indexed by lactate production) was unaffected or slightly elevated. The effects on medium and cell layer alkaline phosphatase were concentration dependent with maximal inhibition occurring at 600 micrograms nicotine/ml. Nicotine essentially did not affect the noncollagenous protein content of the cell layer, but did inhibit collagen synthesis (hydroxylation of [ 3 H]proline and collagenase-digestible protein) at 100, 300, and 600 micrograms/ml. Release of [ 3 H]hydroxyproline to the medium was also decreased in a dose-dependent manner, as was the collagenase-digestible protein for both the medium and cell layer. In contrast, DNA synthesis (incorporation of [ 3 H]thymidine) was more than doubled by the alkaloid, whereas total DNA content was slightly inhibited at 600 micrograms/ml, suggesting stimulated cell turnover. Morphologic changes occurred in nicotine-treated cells including rounding up, detachment, and the occurrence of numerous large vacuoles. These results suggest that steps to reduce the salivary concentration of nicotine in smokeless tobacco users might diminish damaging effects of this product on alveolar bone

  10. The Ebola Virus Nucleoprotein Recruits the Host PP2A-B56 Phosphatase to Activate Transcriptional Support Activity of VP30

    DEFF Research Database (Denmark)

    Kruse, Thomas; Biedenkopf, Nadine; Hertz, Emil Peter Thrane

    2018-01-01

    Transcription of the Ebola virus genome depends on the viral transcription factor VP30 in its unphosphorylated form, but the underlying molecular mechanism of VP30 dephosphorylation is unknown. Here we show that the Ebola virus nucleoprotein (NP) recruits the host PP2A-B56 protein phosphatase......A-B56 and show that it suppresses Ebola virus transcription and infection. This work dissects the molecular mechanism of VP30 dephosphorylation by PP2A-B56, and it pinpoints this phosphatase as a potential target for therapeutic intervention....

  11. Stimulated initiation of mitogen-activated protein kinase phosphatase-1 (MKP-1) gene transcription involves the synergistic action of multiple cis-acting elements in the proximal promoter.

    Science.gov (United States)

    Ryser, Stephan; Massiha, Abbas; Piuz, Isabelle; Schlegel, Werner

    2004-01-01

    Mitogen-activated protein kinases (MAPKs) are inactivated by a dual specificity phosphatase, MAPK phosphatase-1 (MKP-1). MKP-1 is transcribed as an immediate early response gene (IEG) following various stimuli. In the pituitary cell line GH4C1, MKP-1 gene transcription is strongly induced by thyrotropin-releasing hormone (TRH) as well as by epidermal growth factor (EGF) as a consequence of activated MAPK/extracellular-signal-regulated kinase (ERK) signalling. Intriguingly, reporter gene analysis with the MKP-1 promoter showed strong basal transcription, but only limited induction by TRH and EGF. Site-directed mutagenesis of the reporter construct combined with band-shift and in vivo studies revealed that part of the constitutive activity of the MKP-1 promoter resides in two GC boxes bound by Sp1 and Sp3 transcription factors in the minimal promoter. Basal transcription of transiently transfected luciferase reporter can be initiated by either of the two GC boxes or also by either of the two cAMP/Ca(2+) responsive elements or by the E-box present in the proximal promoter. On the other hand, when analysed by stable transfection, the five responsive elements are acting in synergy to transactivate the MKP-1 proximal promoter. We show in this study that the MKP-1 promoter can function as a constitutive promoter or as a rapid and transient sensor for the activation state of MAPKs/ERKs. This dual mode of transcription initiation may have different consequences for the control of a block to elongation situated in the first exon of the MKP-1 gene, as described previously [Ryser, Tortola, van Haasteren, Muda, Li and Schlegel (2001) J. Biol. Chem. 276, 33319-33327]. PMID:14609431

  12. The oncogenic phosphatase PPM1D confers cisplatin resistance in ovarian carcinoma cells by attenuating checkpoint kinase 1 and p53 activation.

    Science.gov (United States)

    Ali, A Y; Abedini, M R; Tsang, B K

    2012-04-26

    Cisplatin (CDDP: cis-diamminedichloroplatinum) resistance is a major hurdle in the treatment of human ovarian cancer (OVCA). A better understanding of the mechanisms of CDDP resistance can greatly improve therapeutic outcome for patients. A determinant of CDDP sensitivity in OVCA, p53, is activated by checkpoint kinase 1 (Chk1) in response to DNA damage. Although the oncogenic phosphatase protein phosphatase magnesium-dependent 1 (PPM1D) can deactivate both p53 and Chk1 through site-specific dephosphorylation, whether PPM1D has a role in CDDP resistance is unknown. Here, using pair-matched wild-type p53 CDDP-sensitive (OV2008) and -resistant (C13*) cells, and p53-compromised CDDP-resistant cells (A2780cp, OCC-1, OVCAR-3 and SKOV3), we have demonstrated (i) the existence of site-specific differences in phospho-Ser-Chk1 content between sensitive and resistant cells in response to CDDP; (ii) PPM1D, but not phosphoinositide-3-kinase-related kinase Ataxia Telangiectasia and Rad3 related protein (ATR), is important in the regulation of CDDP-induced Chk1 activation and OVCA cell chemosensitivity; (iii) PPM1D downregulation sensitizes resistant cells to CDDP primarily by activating Chk1 and p53. Our findings establish for the first time that PPM1D confers CDDP resistance in OVCA cells through attenuating CDDP-induced, Chk1-mediated, p53-dependent apoptosis. These findings extend the current knowledge on the molecular and cellular basis of cisplatin resistance and offer the rationale for PPMID as a potential target for treatment of chemoresistant OVCA.

  13. The modulator protein dissociates the catalytic subunit of hepatic protein phosphatase G from glycogen.

    OpenAIRE

    Bollen, M; Stalmans, W

    1988-01-01

    1. The phosphorylase phosphatase and glycogen-synthase phosphatase activities associated with the glycogen particles from rat liver were progressively inhibited by incubation with modulator protein. However, the phosphorylase phosphatase activity of the catalytic subunit was entirely recovered after destruction of the modulator and the regulatory subunit(s) by trypsin. 2. Inhibition of protein phosphatase G by modulator was associated with a translocation of the phosphorylase phosphatase acti...

  14. Nuclear Envelope Phosphatase 1-Regulatory Subunit 1 (Formerly TMEM188) Is the Metazoan Spo7p Ortholog and Functions in the Lipin Activation Pathway*

    Science.gov (United States)

    Han, Sungwon; Bahmanyar, Shirin; Zhang, Peixiang; Grishin, Nick; Oegema, Karen; Crooke, Roseann; Graham, Mark; Reue, Karen; Dixon, Jack E.; Goodman, Joel M.

    2012-01-01

    Lipin-1 catalyzes the formation of diacylglycerol from phosphatidic acid. Lipin-1 mutations cause lipodystrophy in mice and acute myopathy in humans. It is heavily phosphorylated, and the yeast ortholog Pah1p becomes membrane-associated and active upon dephosphorylation by the Nem1p-Spo7p membrane complex. A mammalian ortholog of Nem1p is the C-terminal domain nuclear envelope phosphatase 1 (CTDNEP1, formerly “dullard”), but its Spo7p-like partner is unknown, and the need for its existence is debated. Here, we identify the metazoan ortholog of Spo7p, TMEM188, renamed nuclear envelope phosphatase 1-regulatory subunit 1 (NEP1-R1). CTDNEP1 and NEP1-R1 together complement a nem1Δspo7Δ strain to block endoplasmic reticulum proliferation and restore triacylglycerol levels and lipid droplet number. The two human orthologs are in a complex in cells, and the amount of CTDNEP1 is increased in the presence of NEP1-R1. In the Caenorhabditis elegans embryo, expression of nematode CTDNEP1 and NEP1-R1, as well as lipin-1, is required for normal nuclear membrane breakdown after zygote formation. The expression pattern of NEP1-R1 and CTDNEP1 in human and mouse tissues closely mirrors that of lipin-1. CTDNEP1 can dephosphorylate lipins-1a, -1b, and -2 in human cells only in the presence of NEP1-R1. The nuclear fraction of lipin-1b is increased when CTDNEP1 and NEP1-R1 are co-expressed. Therefore, NEP1-R1 is functionally conserved from yeast to humans and functions in the lipin activation pathway. PMID:22134922

  15. Alkaline phosphatase: an overview.

    Science.gov (United States)

    Sharma, Ujjawal; Pal, Deeksha; Prasad, Rajendra

    2014-07-01

    Alkaline phosphatase (ALP; E.C.3.I.3.1.) is an ubiquitous membrane-bound glycoprotein that catalyzes the hydrolysis of phosphate monoesters at basic pH values. Alkaline phosphatase is divided into four isozymes depending upon the site of tissue expression that are Intestinal ALP, Placental ALP, Germ cell ALP and tissue nonspecific alkaline phosphatase or liver/bone/kidney (L/B/K) ALP. The intestinal and placental ALP loci are located near the end of long arm of chromosome 2 and L/B/K ALP is located near the end of the short arm of chromosome 1. Although ALPs are present in many mammalian tissues and have been studied for the last several years still little is known about them. The bone isoenzyme may be involved in mammalian bone calcification and the intestinal isoenzyme is thought to play a role in the transport of phosphate into epithelial cells of the intestine. In this review, we tried to provide an overview about the various forms, structure and functions of alkaline phosphatase with special focus on liver/bone/kidney alkaline phosphatase.

  16. Biocatalytic Route to Surface Active Lipid

    DEFF Research Database (Denmark)

    Cheong, Ling-Zhi; Xu, Xuebing

    Lipid can be structurally modified in order to attain improved functional properties. This work look into the possibilities of developing surface active lipids with improved functional properties through biocatalytic route. Biocatalytic route to surface active lipid are usually complex involving ...... distinct self assembling property and find useful application in surfactant industry.......Lipid can be structurally modified in order to attain improved functional properties. This work look into the possibilities of developing surface active lipids with improved functional properties through biocatalytic route. Biocatalytic route to surface active lipid are usually complex involving...

  17. Effect of Low Dose Gamma Radiation Upon Phosphatase Activity in Blood Plasma of Chicken Hatched from Eggs Irradiated on the Seventh Day of Incubation

    International Nuclear Information System (INIS)

    Kraljevic, P.; Vilic, M.; Miljanic, S.; Simpraga, M.

    2008-01-01

    In our earlier studies chickens hatched from eggs irradiated with 0.15 Gy gamma rays before incubation showed a significantly higher growth than controls during the fattening period (1-42 days). The activity of aspartate-aminotransferase (AST), alanine-aminotransferase (ALT), acid phosphatase (ACP) and plasma glucose in the same chickens were also significantly higher. These results suggested that low-dose gamma-radiation stimulated certain metabolic processes in chickens hatched from eggs irradiated before incubation. Investigating the effect of low dose gamma radiation upon transferases activity in blood plasma of chickens hatched from eggs irradiated on the 7th day of incubation, i.e. in the time when organogenesis is completely finished, we found that on day 10, AST and ALT activity was significantly higher in the blood plasma of those chickens, whereas it significantly dropped for both enzymes on day 20. This time the goal of study was to determine the effect of low-dose gamma radiation on ACP and alkaline phosphatase (ALP) activity in the blood plasma of chickens hatched from eggs irradiated on the 7th day of incubation. The eggs of heavy breeding chickens (Avian, line 34) were exposed to 0.15 Gy of gamma radiation (60Co) on the seventh day of incubation. The control group included chickens hatched from non-irradiated eggs. All other conditions were the same for both groups. After hatching, blood samples were taken from the wing vein on days 1, 3, 5, 7, 10, 20, 32 and 42. The activity of both enzymes was determined spectrophotometrically using Boehringer Mannheim GmbH optimised kits. ACP activity was significantly lower in the blood plasma of chickens hatched from irradiated eggs on day 3 (P<0,01), 5 (P<0,05) and 10 (P<0,05). Throughout the experimental period ALP activity did not statistically significantly change. Our results indicate that exposure of eggs to low-dose gamma radiation on the seventh day of incubation reduces ACP activity in the blood plasma

  18. Effects of dietary vitamin E on mucosal maltase and alkaline phosphatase enzyme activities and on the amount of mucosal malonyldialdehyde in broiler chickens.

    Science.gov (United States)

    Farrokhifar, Seyed Hamid; Ali Jafari, Ramezan; Erfani Majd, Naeem; Fatemi Tabatabaee, Seyed Reza; Mayahi, Mansour

    2013-01-01

    The effects of dietary vitamin E levels on mucosal maltase and alkaline phosphatase (ALP) enzyme activities and on the amount of mucosal malonyldialdehyde (MDA) in broiler chickens were studied in the present study. One hundred and eighty of male day old broiler chicks (Ross 308 strain) were randomly assigned into five groups, each with three replicates and 12 chicks in each replicate. Chickens in group A were fed corn-soy- based diet, while those in groups B, C, D and E were fed the same diet with 20, 60, 180, and 540 mg kg(-1) vitamin E supplement (d-alpha tocopherol), respectively. Six birds were randomly chosen from each group, and were euthanized on days 10, 21, 32, and 42 of age. One segment of small intestine outset was homogenized and mucosal ALP and maltase activity were measured. Moreover, mucosal lipid peroxidate amount was measured to reveal the impact of vitamin E on oxidative stress. Maltase activity was increased with the increase of vitamin E up to 60 mg kg(-1) of diet while with further levels, it was decreased. Addition of 60 mg kg(-1) of vitamin E to the diet significantly increased ALP enzyme activity (p ≤ 0.001). Addition of 540 mg kg(-1) of vitamin E supplement to the diet led to the minimum amount of MDA at 32 days of age. It may be concluded that supplementation of broiler's diet with 60 mg kg(-1) of vitamin E can increase mucosal maltase and ALP enzyme activity.

  19. MAP kinase phosphatase-2 plays a key role in the control of infection with Toxoplasma gondii by modulating iNOS and arginase-1 activities in mice.

    Directory of Open Access Journals (Sweden)

    Stuart Woods

    2013-08-01

    Full Text Available The dual specific phosphatase, MAP kinase phosphatase-2 (MKP-2 has recently been demonstrated to negatively regulate macrophage arginase-1 expression, while at the same time to positively regulate iNOS expression. Consequently, MKP-2 is likely to play a significant role in the host interplay with intracellular pathogens. Here we demonstrate that MKP-2(-/- mice on the C57BL/6 background have enhanced susceptibility compared with wild-type counterparts following infection with type-2 strains of Toxoplasma gondii as measured by increased parasite multiplication during acute infection, increased mortality from day 12 post-infection onwards and increased parasite burdens in the brain, day 30 post-infection. MKP-2(-/- mice did not, however, demonstrate defective type-1 responses compared with MKP-2(+/+ mice following infection although they did display significantly reduced serum nitrite levels and enhanced tissue arginase-1 expression. Early resistance to T. gondii in MKP-2(+/+, but not MKP-2(-/-, mice was nitric oxide (NO dependent as infected MKP-2(+/+, but not MKP-2(-/- mice succumbed within 10 days post-infection with increased parasite burdens following treatment with the iNOS inhibitor L-NAME. Conversely, treatment of infected MKP-2(-/- but not MKP-2(+/+ mice with nor-NOHA increased parasite burdens indicating a protective role for arginase-1 in MKP-2(-/- mice. In vitro studies using tachyzoite-infected bone marrow derived macrophages and selective inhibition of arginase-1 and iNOS activities confirmed that both iNOS and arginase-1 contributed to inhibiting parasite replication. However, the effects of arginase-1 were transient and ultimately the role of iNOS was paramount in facilitating long-term inhibition of parasite multiplication within macrophages.

  20. Partial characterization and response under hyperregulating conditions of Na+-K+ ATPase and levamisole-sensitive alkaline phosphatase activities in chela muscle of the euryhaline crab Cyrtograpsus angulatus

    Directory of Open Access Journals (Sweden)

    Silvina Andrea Pinoni

    2008-03-01

    Full Text Available The occurrence, characteristics and response to changes in environmental salinity of Na+-K+ ATPase and levamisole-sensitive alkaline phosphatase (AP activities were studied in chela muscle of the euryhaline crab Cyrtograpsus angulatus. Chela muscle exhibited an Na+-K+ ATPase activity which was strongly dependent on ATP concentration, pH and temperature of the reaction mixture. Maximal activity was found at 1 mM ATP, 30-37°C and pH 7.4. Levamisole-sensitive AP activity was characterised at physiological pH 7.4 and at pH 8.0. I50 for levamisole-sensitive AP activity was 8.8 mM and 8.0 mM at pH 7.4 and 8.0, respectively. At both pH levels, levamisole-sensitive AP activity exhibited Michaelis-Menten kinetics (Km=3.451 mM and 6.906 mM at pH 7.4 and 8.0, respectively. Levamisole-sensitive AP activities were strongly affected by temperature, exhibiting a peak at 37ºC. In crabs acclimated to low salinity (10; hyperegulating conditions, Na+-K+ ATPase activity and levamisole-sensitive AP activity at the physiological pH were higher than in 35 psu (osmoconforming conditions. The response to low salinity suggests that both activities could be components of muscle regulatory mechanisms at the biochemical level secondary to hyperegulation of C. angulatus. The study of these activities under hyperegulating conditions contributes to a better understanding of the complexity of biochemical mechanisms underlying the adaptive process of euryhaline crabs.

  1. Glucose-6-phosphatase deficiency

    Directory of Open Access Journals (Sweden)

    Labrune Philippe

    2011-05-01

    Full Text Available Abstract Glucose-6-phosphatase deficiency (G6P deficiency, or glycogen storage disease type I (GSDI, is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, between the ages of 3 to 4 months by symptoms of hypoglycemia (tremors, seizures, cyanosis, apnea. Patients have poor tolerance to fasting, marked hepatomegaly, growth retardation (small stature and delayed puberty, generally improved by an appropriate diet, osteopenia and sometimes osteoporosis, full-cheeked round face, enlarged kydneys and platelet dysfunctions leading to frequent epistaxis. In addition, in GSDIb, neutropenia and neutrophil dysfunction are responsible for tendency towards infections, relapsing aphtous gingivostomatitis, and inflammatory bowel disease. Late complications are hepatic (adenomas with rare but possible transformation into hepatocarcinoma and renal (glomerular hyperfiltration leading to proteinuria and sometimes to renal insufficiency. GSDI is caused by a dysfunction in the G6P system, a key step in the regulation of glycemia. The deficit concerns the catalytic subunit G6P-alpha (type Ia which is restricted to expression in the liver, kidney and intestine, or the ubiquitously expressed G6P transporter (type Ib. Mutations in the genes G6PC (17q21 and SLC37A4 (11q23 respectively cause GSDIa and Ib. Many mutations have been identified in both genes,. Transmission is autosomal recessive. Diagnosis is based on clinical presentation, on abnormal basal values and absence of hyperglycemic response to glucagon. It can be confirmed by demonstrating a deficient activity of a G6P system component in a liver biopsy. To date, the diagnosis is most

  2. Glucose-6-phosphatase deficiency.

    Science.gov (United States)

    Froissart, Roseline; Piraud, Monique; Boudjemline, Alix Mollet; Vianey-Saban, Christine; Petit, François; Hubert-Buron, Aurélie; Eberschweiler, Pascale Trioche; Gajdos, Vincent; Labrune, Philippe

    2011-05-20

    Glucose-6-phosphatase deficiency (G6P deficiency), or glycogen storage disease type I (GSDI), is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, between the ages of 3 to 4 months by symptoms of hypoglycemia (tremors, seizures, cyanosis, apnea). Patients have poor tolerance to fasting, marked hepatomegaly, growth retardation (small stature and delayed puberty), generally improved by an appropriate diet, osteopenia and sometimes osteoporosis, full-cheeked round face, enlarged kydneys and platelet dysfunctions leading to frequent epistaxis. In addition, in GSDIb, neutropenia and neutrophil dysfunction are responsible for tendency towards infections, relapsing aphtous gingivostomatitis, and inflammatory bowel disease. Late complications are hepatic (adenomas with rare but possible transformation into hepatocarcinoma) and renal (glomerular hyperfiltration leading to proteinuria and sometimes to renal insufficiency). GSDI is caused by a dysfunction in the G6P system, a key step in the regulation of glycemia. The deficit concerns the catalytic subunit G6P-alpha (type Ia) which is restricted to expression in the liver, kidney and intestine, or the ubiquitously expressed G6P transporter (type Ib). Mutations in the genes G6PC (17q21) and SLC37A4 (11q23) respectively cause GSDIa and Ib. Many mutations have been identified in both genes,. Transmission is autosomal recessive. Diagnosis is based on clinical presentation, on abnormal basal values and absence of hyperglycemic response to glucagon. It can be confirmed by demonstrating a deficient activity of a G6P system component in a liver biopsy. To date, the diagnosis is most commonly confirmed

  3. A Conserved Motif Provides Binding Specificity to the PP2A-B56 Phosphatase

    DEFF Research Database (Denmark)

    Hertz, Emil Peter Thrane; Kruse, Thomas; Davey, Norman E

    2016-01-01

    -exposed pocket on PP2A regulatory B56 subunits binds to a consensus sequence on interacting proteins, which we term the LxxIxE motif. The composition of the motif modulates the affinity for B56, which in turn determines the phosphorylation status of associated substrates. Phosphorylation of amino acid residues......Dynamic protein phosphorylation is a fundamental mechanism regulating biological processes in all organisms. Protein phosphatase 2A (PP2A) is the main source of phosphatase activity in the cell, but the molecular details of substrate recognition are unknown. Here, we report that a conserved surface...... within the motif increases B56 binding, allowing integration of kinase and phosphatase activity. We identify conserved LxxIxE motifs in essential proteins throughout the eukaryotic domain of life and in human viruses, suggesting that the motifs are required for basic cellular function. Our study provides...

  4. The spatial distribution of acid phosphatase activity in ectomycorrhizal tissues depends on soil fertility and morphotype, and relates to host plant phosphorus uptake.

    Science.gov (United States)

    Alvarez, Maricel; Huygens, Dries; Díaz, Leila Milena; Villanueva, Claudia Añazco; Heyser, Wolfgang; Boeckx, Pascal

    2012-01-01

    Acid phosphatase (ACP) enzymes are involved in the mobilization of soil phosphorus (P) and polyphosphate accumulated in the fungal tissues of ectomycorrhizal roots, thereby influencing the amounts of P that are stored in the fungus and transferred to the host plant. This study evaluated the effects of ectomycorrhizal morphotype and soil fertility on ACP activity in the extraradical mycelium (ACP(myc)), the mantle (ACP(mantle)) and the Hartig net region (ACP(Hartig)) of ectomycorrhizal Nothofagus obliqua seedlings. ACP activity was quantified in vivo using enzyme-labelled fluorescence-97 (ELF-97) substrate, confocal laser microscopy and digital image processing routines. There was a significant effect of ectomycorrhizal morphotype on ACP(myc), ACP(mantle) and ACP(Hartig), while soil fertility had a significant effect on ACP(myc) and ACP(Hartig). The relative contribution of the mantle and the Hartig net region to the ACP activity on the ectomycorrhizal root was significantly affected by ectomycorrhizal morphotype and soil fertility. A positive correlation between ACP(Hartig) and the shoot P concentration was found, providing evidence that ACP activity at the fungus:root interface is involved in P transfer from the fungus to the host. It is concluded that the spatial distribution of ACP in ectomycorrhizas varies as a function of soil fertility and colonizing fungus. © 2011 Blackwell Publishing Ltd.

  5. A novel strategy for the development of selective active-site inhibitors of the protein tyrosine phosphatase-like proteins islet-cell antigen 512 (IA-2) and phogrin (IA-2 beta)

    DEFF Research Database (Denmark)

    Drake, P.G.; Peters, Günther H.j.; Andersen, H.S.

    2003-01-01

    Islet-cell antigen 512 (IA-2) and phogrin (IA-2) are atypical members of he receptor protein tyrosine phosphatase (PTP) family that are characterized by a lack of activity against conventional PTP substrates. The physiological role(s) of these proteins remain poorly defined, although recent studi...

  6. Cdc14 phosphatase

    DEFF Research Database (Denmark)

    Machín, Félix; Quevedo Rodriguez, Oliver; Ramos-Pérez, Cristina

    2016-01-01

    Cycling events in nature start and end to restart again and again. In the cell cycle, whose purpose is to become two where there was only one, cyclin-dependent kinases (CDKs) are the beginning and, therefore, phosphatases must play a role in the ending. Since CDKs are drivers of the cell cycle an...

  7. Minimal hepatic glucose-6-phosphataseactivity required to sustain survival and prevent hepatocellular adenoma formation in murine glycogen storage disease type Ia

    Science.gov (United States)

    Lee, Young Mok; Kim, Goo-Young; Pan, Chi-Jiunn; Mansfield, Brian C.; Chou, Janice Y.

    2015-01-01

    Glycogen storage disease type Ia (GSD-Ia), characterized by impaired glucose homeostasis and chronic risk of hepatocellular adenoma (HCA), is caused by a deficiency in glucose-6-phosphatase-α (G6Pase-α or G6PC) activity. In a previous 70–90 week-study, we showed that a recombinant adeno-associated virus (rAAV) vector-mediated gene transfer that restores more than 3% of wild-type hepatic G6Pase-α activity in G6pc−/− mice corrects hepatic G6Pase-α deficiency with no evidence of HCA. We now examine the minimal hepatic G6Pase-α activity required to confer therapeutic efficacy. We show that rAAV-treated G6pc−/− mice expressing 0.2% of wild-type hepatic G6Pase-α activity suffered from frequent hypoglycemic seizures at age 63–65 weeks but mice expressing 0.5–1.3% of wild-type hepatic G6Pase-α activity (AAV-LL mice) sustain 4–6 h of fast and grow normally to age 75–90 weeks. Despite marked increases in hepatic glycogen accumulation, the AAV-LL mice display no evidence of hepatic abnormalities, hepatic steatosis, or HCA. Interprandial glucose homeostasis is maintained by the G6Pase-α/glucose-6-phosphate transporter (G6PT) complex, and G6PT-mediated microsomal G6P uptake is the rate-limiting step in endogenous glucose production. We show that hepatic G6PT activity is increased in AAV-LL mice. These findings are encouraging for clinical studies of G6Pase-α gene-based therapy for GSD-Ia. PMID:26937391

  8. Minimal hepatic glucose-6-phosphataseactivity required to sustain survival and prevent hepatocellular adenoma formation in murine glycogen storage disease type Ia

    Directory of Open Access Journals (Sweden)

    Young Mok Lee

    2015-06-01

    Full Text Available Glycogen storage disease type Ia (GSD-Ia, characterized by impaired glucose homeostasis and chronic risk of hepatocellular adenoma (HCA, is caused by a deficiency in glucose-6-phosphatase-α (G6Pase-α or G6PC activity. In a previous 70–90 week-study, we showed that a recombinant adeno-associated virus (rAAV vector-mediated gene transfer that restores more than 3% of wild-type hepatic G6Pase-α activity in G6pc−/− mice corrects hepatic G6Pase-α deficiency with no evidence of HCA. We now examine the minimal hepatic G6Pase-α activity required to confer therapeutic efficacy. We show that rAAV-treated G6pc−/− mice expressing 0.2% of wild-type hepatic G6Pase-α activity suffered from frequent hypoglycemic seizures at age 63–65 weeks but mice expressing 0.5–1.3% of wild-type hepatic G6Pase-α activity (AAV-LL mice sustain 4–6 h of fast and grow normally to age 75–90 weeks. Despite marked increases in hepatic glycogen accumulation, the AAV-LL mice display no evidence of hepatic abnormalities, hepatic steatosis, or HCA. Interprandial glucose homeostasis is maintained by the G6Pase-α/glucose-6-phosphate transporter (G6PT complex, and G6PT-mediated microsomal G6P uptake is the rate-limiting step in endogenous glucose production. We show that hepatic G6PT activity is increased in AAV-LL mice. These findings are encouraging for clinical studies of G6Pase-α gene-based therapy for GSD-Ia.

  9. Leucine Aminopeptidase, β-Glucosidase and Alkaline Phosphatase Activity Rates and Their Significance in Nutrient Cycles in Some Coastal Mediterranean Sites

    Directory of Open Access Journals (Sweden)

    Gabriella Caruso

    2010-03-01

    Full Text Available In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU on organic polymers (proteins, organic phosphates and polysaccharides, respectively. Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the “potential” metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also

  10. Leucine aminopeptidase, beta-glucosidase and alkaline phosphatase activity rates and their significance in nutrient cycles in some coastal Mediterranean sites.

    Science.gov (United States)

    Caruso, Gabriella

    2010-03-29

    In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and beta-glucosidase, beta-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the "potential" metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and beta-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. beta-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon

  11. Leucine Aminopeptidase, β-Glucosidase and Alkaline Phosphatase Activity Rates and Their Significance in Nutrient Cycles in Some Coastal Mediterranean Sites

    Science.gov (United States)

    Caruso, Gabriella

    2010-01-01

    In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the “potential” metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon

  12. Phenylarsine Oxide Binding Reveals Redox-Active and Potential Regulatory Vicinal Thiols on the Catalytic Subunit of Protein Phosphatase 2A

    Science.gov (United States)

    Melideo, Scott L.; Healey, Adriana E.; Lucas, Eugene J.; Koval, Jason A.

    2011-01-01

    Our earlier finding that the activity of protein phosphatase 2A from rat brain is inhibited by micromolar concentrations of the dithiol cross-linking reagent phenylarsine oxide (PAO) has encouraged the hypothesis that the catalytic subunit (PP2Ac) of PP2A contains one or more pairs of closely-spaced (vicinal) thiol pairs that may contribute to regulation of the enzyme. The results of the present study demonstrate using immobilized PAO-affinity chromatography that PP2Ac from rat brain formed stable DTT-sensitive adducts with PAO with or without associated regulatory subunits. In addition, a subset of the PAO-binding vicinal thiols of PP2Ac was readily oxidized to disulfide bonds in vitro. Importantly, a small fraction of PP2Ac was still found to contain disulfide bonds after applying stringent conditions designed to prevent protein disulfide bond formation during homogenization and fractionation of the brains. These findings establish the presence of potentially regulatory and redox-active PAO-binding vicinal thiols on the catalytic subunit of PP2A and suggest that a population of PP2Ac may contain disulfide bonds in vivo. PMID:21080067

  13. Evaluation of Milk Trace Elements, Lactate Dehydrogenase, Alkaline Phosphatase and Aspartate Aminotransferase Activity of Subclinical Mastitis as and Indicator of Subclinical Mastitis in Riverine Buffalo (Bubalus bubalis)

    Science.gov (United States)

    Guha, Anirban; Gera, Sandeep; Sharma, Anshu

    2012-01-01

    Mastitis is a highly morbid disease that requires detection at the subclinical stage. Tropical countries like India mainly depend on milch buffaloes for milk. The present study was conducted to investigate whether the trace minerals viz. copper (Cu), iron (Fe), zinc (Zn), cobalt (Co) and manganese (Mn) and enzyme activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in riverine buffalo milk can be used as an indicator of subclinical mastitis (SCM) with the aim of developing suitable diagnostic kit for SCM. Trace elements and enzyme activity in milk were estimated with Atomic absorption Spectrophotometer, GBC 932 plus and biochemical methods, respectively. Somatic cell count (SCC) was done microscopically. The cultural examination revealed Gram positive bacteria as the most prevalent etiological agent. A statistically significant (p<0.01) increase in SCC, Fe, Zn, Co and LDH occurred in SCM milk containing gram positive bacterial agents only. ALP was found to be elevated in milk infected by both gram positive and negative bacteria. The percent sensitivity, specificity and accuracy, predictive values and likelihood ratios were calculated taking bacterial culture examination and SCC≥2×105 cells/ml of milk as the benchmark. Only ALP and Zn, the former being superior, were found to be suitable for diagnosis of SCM irrespective of etiological agents. LDH, Co and Fe can be introduced in the screening programs where Gram positive bacteria are omnipresent. It is recommended that both ALP and Zn be measured together in milk to diagnose buffalo SCM, irrespective of etiology. PMID:25049573

  14. A dimeric urea of the bisabolene sesquiterpene from the Okinawan marine sponge Axinyssa sp. inhibits protein tyrosine phosphatase 1B activity in Huh-7 human hepatoma cells.

    Science.gov (United States)

    Abdjul, Delfly B; Kanno, Syu-Ichi; Yamazaki, Hiroyuki; Ukai, Kazuyo; Namikoshi, Michio

    2016-01-15

    Protein tyrosine phosphatase 1B (PTP1B) plays an important role as a negative regulator of the insulin and leptin signaling pathways. Therefore, this enzyme is regarded as an attractive therapeutic target for the treatment of type 2 diabetes and obesity. Our screening program for PTP1B inhibitors led to the isolation of four sesquiterpenes and sterol: N,N'-bis[(6R,7S)-7-amino-7,8-dihydro-α-bisabolen-7-yl]urea (1), (6R,7S)-7-amino-7,8-dihydro-α-bisabolene (2), (1R,6S,7S,10S)-10-isothiocyanato-4-amorphene (3), axinisothiocyanate J (4), and axinysterol (5) from the marine sponge Axinyssa sp. collected at Iriomote Island. Of these, compound 1 was the most potent inhibitor of PTP1B activity (IC50=1.9μM) without cytotoxicity at 50μM in two human cancer cell lines, hepatoma Huh-7 and bladder carcinoma EJ-1 cells. Compound 1 also moderately enhanced the insulin-stimulated phosphorylation levels of Akt in Huh-7 cells. Therefore, compound 1 has potential as a new type of anti-diabetic drug candidate possessing PTP1B inhibitory activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The antioxidant effects of vitamin C on liver enzymes: aspartate aminotransferase, alanine aminotranferease, alkaline phosphatase and gamma-glutamyltransferase activities in rats under Paraquat insult

    Directory of Open Access Journals (Sweden)

    Benjamin Nnamdi Okolonkwo

    2013-06-01

    Full Text Available Paraquat (PQ is a bipyridylium herbicide; applied around trees in orchards and between crop rows to control broad-leaved and grassy weeds. Its oxidation results in the formation of superoxides which causes damage to cellular components. In this study, we determined the antioxidant effect vitamin C has on the liver enzymes [aspartate aminotransferase (SGOT, alanine aminotranferease (SGPT, alkaline phosphatase (ALP, and gamma-glutamyltransferase (GGT] of rats under this toxic insult. Male rats in groups (A, B, C and D were intraperitoneally injected with different sublethal increasing doses (0, 0.02, 0.04 and 0.06 g/kg body weigh of PQ respectively on monthly basis. Subsequently, the subgroups (A2, B2, C2 and D2 were given orally, 200 mg/L vitamin C, while the subgroups A1, B1, C1, and D1, received only water. Four animals per subgroup were decapitated on monthly basis and blood samples taken for enzyme assay. The parameters studied were - SGOT, SGPT, ALP and GGT - liver enzymes. The dose and time dependent PQ toxicity effect resulted in highly elevated Liver enzymes activities. The subgroups on vitamin C had significantly lower enzyme activities when compared to the same subgroups on only PQ insult. But the values were high when compared to the control subgroups (A1 and A2. These results were indication that vitamin C when given at moderate doses and maintained for a longer period could be a life saving adjunct to toxic insult.

  16. Arbuscular mycorrhizal fungal diversity, root colonization, and soil alkaline phosphatase activity in response to maize-wheat rotation and no-tillage in North China.

    Science.gov (United States)

    Hu, Junli; Yang, Anna; Zhu, Anning; Wang, Junhua; Dai, Jue; Wong, Ming Hung; Lin, Xiangui

    2015-07-01

    Monitoring the effects of no-tillage (NT) in comparison with conventional tillage (CT) on soil microbes could improve our understanding of soil biochemical processes and thus help us to develop sound management strategies. The objective of this study was to compare the species composition and ecological function of soil arbuscular mycorrhizal (AM) fungi during the growth and rotation of crops under NT and CT. From late June 2009 to early June 2010, 32 topsoil (0-15 cm) samples from four individual plots per treatment (CT and NT) were collected at both the jointing and maturation stages of maize (Zea mays L.) and wheat (Triticum aestivum L.) from a long-term experimental field that was established in an Aquic Inceptisol in North China in June 2006. The AM fungal spores were isolated and identified and then used to calculate species diversity indices, including the Shannon- Wiener index (H'), Evenness (E), and Simpson's index (D). The root mycorrhizal colonization and soil alkaline phosphatase activity were also determined. A total of 34 species of AM fungi within nine genera were recorded. Compared with NT, CT negatively affected the soil AM fungal community at the maize sowing stage, leading to decreases in the average diversity indices (from 2.12, 0.79, and 0.82 to 1.79, 0.72, and 0.74 for H', E, and D, respectively), root mycorrhizal colonization (from 28% to 20%), soil alkaline phosphatase activity (from 0.24 to 0.19 mg/g/24 h) and available phosphorus concentration (from 17.4 to 10.5 mg/kg) at the maize jointing stage. However, reductions in diversity indices of H', E, and D were restored to 2.20, 0.81, and 0.84, respectively, at the maize maturation stage. CT should affect the community again at the wheat sowing stage; however, a similar restoration in the species diversity of AM fungi was completed before the wheat jointing stage, and the highest Jaccard index (0.800) for similarity in the species composition of soil AM fungi between CT and NT was recorded at

  17. Identification of a PTEN mutation with reduced protein stability, phosphatase activity, and nuclear localization in Hong Kong patients with autistic features, neurodevelopmental delays, and macrocephaly.

    Science.gov (United States)

    Wong, Chi Wai; Or, Penelope Mei Yu; Wang, Yubing; Li, Lisha; Li, Jing; Yan, Mingfei; Cao, Ye; Luk, Ho Ming; Tong, Tony Ming For; Leslie, Nick R; Lo, Ivan Fai-Man; Choy, Kwong Wai; Chan, Andrew Man Lok

    2018-04-02

    PTEN is a tumor suppressor gene inactivated in over 30% of human cancers. It encodes a lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase signaling pathway. Germline mutation frequently occurs in this gene in patients diagnosed with PTEN Hamartoma Tumor Syndrome (PHTS). PHTS individuals are characterized by macrocephaly, benign growth of multiple tissues and increased tumor risk. In addition, autistic phenotypes are found in 10-20% of individuals carrying the germline PTEN mutation with macrocephaly. In this report, 13 suspected PHTS patients were screened for mutation in the PTEN gene. A missense variant (c. 302T > C) substituting the isoleucine at codon 101 to a threonine, a single nucleotide insertion (c. 327-328insC) causing a frame shift mutation and termination at codon 109, and a nonsense variant (c. 1003C > T) truncated the protein at codon 335 were identified. The I101T mutation significantly reduced PTEN protein expression levels by 2.5- to 4.0-fold. Mechanistically, I101T reduced the protein half-life of PTEN possibly due to enhanced polyubiquitination at Lysine 13. However, the I101T mutant retained almost 30% of the lipid phosphatase activity of the wild-type protein. Finally, the I101T mutant has reduced phosphorylation at a PTEN auto-dephosphorylation site at Threonine 366 and a lowered ratio of nuclear to cytosolic protein level. These partial losses of multiple PTEN biochemical functions may contribute to the tissue overgrowth and autistic features of this PHTS patient. Autism Res 2018. © 2018 The Authors Autism Research published by International Society for Autism Research and Wiley Periodicals, Inc. The genetics of autism spectrum disorders is highly complex with individual risk influenced by both genetic and environmental factors. Mutation in the human PTEN gene confers a high risk of developing autistic behavior. This report revealed that PTEN mutations occurred in 23% of a selected group of Hong Kong

  18. Activation of Src kinase by protein-tyrosine phosphatase-PEST in osteoclasts: comparative analysis of the effects of bisphosphonate and protein-tyrosine phosphatase inhibitor on Src activation in vitro.

    Science.gov (United States)

    Chellaiah, Meenakshi A; Schaller, Michael D

    2009-08-01

    PTP-PEST is involved in the regulation of sealing ring formation in osteoclasts. In this article, we have shown a regulatory role for PTP-PEST on dephosphorylation of c-Src at Y527 and phosphorylation at Y418 in the catalytic site. Activation of Src in osteoclasts by over-expression of PTP-PEST resulted in the phosphorylation of cortactin at Y421 and WASP at Y294. Also enhanced as a result, is the interaction of Src, cortactin, and Arp2 with WASP. Moreover, the number of osteoclasts displaying sealing ring and bone resorbing activity was increased in response to PTP-PEST over-expression as compared with control osteoclasts. Cells expressing constitutively active-Src (527YDeltaF) simulate the effects mediated by PTP-PEST. Treatment of osteoclasts with a bisphosphonate alendronate or a potent PTP inhibitor PAO decreased the activity and phosphorylation of Src at Y418 due to reduced dephosphorylation state at Y527. Therefore, Src-mediated phosphorylation of cortactin and WASP as well as the formation of WASP.cortactin.Arp2 complex and sealing ring were reduced in these osteoclasts. Similar effects were observed in osteoclasts treated with an Src inhibitor PP2. We have shown that bisphosphonates could modulate the function of osteoclasts by inhibiting downstream signaling mediated by PTP-PEST/Src, in addition to its effect on the inhibition of the post-translational modification of small GTP-binding proteins such as Rab, Rho, and Rac as shown by others. The promising effects of the inhibitors PP2 and PAO on osteoclast function suggest a therapeutic approach for patients with bone metastases and osteoporosis as an alternative to bisphosphonates.

  19. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    Science.gov (United States)

    Wang, Chanchan; Sauvageau, Dominic; Elias, Anastasia

    2016-01-20

    A rapid, efficient technique for the attachment of bacteriophages (phages) onto polyhydroxyalkanoate (PHA) surfaces has been developed and compared to three reported methods for phage immobilization. Polymer surfaces were modified to facilitate phage attachment using (1) plasma treatment alone, (2) plasma treatment followed by activation by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS), (3) plasma-initiated acrylic acid grafting, or (4) plasma-initiated acrylic acid grafting with activation by EDC and sulfo-NHS. The impact of each method on the surface chemistry of PHA was investigated using contact angle analysis and X-ray photoelectron spectroscopy. Each of the four treatments was shown to result in both increased hydrophilicity and in the modification of the surface functional groups. Modified surfaces were immersed in suspensions of phage T4 for immobilization. The highest level of phage binding was observed for the surfaces modified by plasma treatment alone. The change in chemical bond states observed for surfaces that underwent plasma treatment is suspected to be the cause of the increased binding of active phages. Plasma-treated surfaces were further analyzed through phage-staining and fluorescence microscopy to assess the surface density of immobilized phages and their capacity to capture hosts. The infective capability of attached phages was confirmed by exposing the phage-immobilized surfaces to the host bacteria Escherichia coli in both plaque and infection dynamic assays. Plasma-treated surfaces with immobilized phages displayed higher infectivity than surfaces treated with other methods; in fact, the equivalent initial multiplicity of infection was 2 orders of magnitude greater than with other methods. Control samples - prepared by immersing polymer surfaces in phage suspensions (without prior plasma treatment) - did not show any bacterial growth inhibition, suggesting they did not bind

  20. Potentiometric assay for acid and alkaline phosphatase

    International Nuclear Information System (INIS)

    Koncki, Robert; Ogonczyk, Dominika; Glab, Stanislaw

    2005-01-01

    Simple potentiometric kinetic assay for evaluation of acid and alkaline phosphatase activity has been developed. Enzymatically catalyzed hydrolysis of monofluorophosphate, the simplest inorganic compound containing P-F bond, has been investigated as the basis of the assays. Fluoride ions formed in the course of the hydrolysis of this specific substrate have been detected using conventional fluoride ion-selective electrode based on membrane made of lanthanum fluoride. The key analytical parameters necessary for sensitive and selective detection of both enzymes have been assessed. Maximal sensitivity of the assays was observed at monofluorophosphate concentration near 10 -3 M. Maximal sensitivity of acid phosphatase assay was found at pH 6.0, but pH of 4.8 is recommended to eliminate effects from alkaline phosphatase. Optimal pH for alkaline phosphatase assay is 9.0. The utility of the developed substrate-sensor system for determination of acid and alkaline phosphatase activity in human serum has been demonstrated

  1. Effects of dietary vitamin E on mucosal maltase and alkaline phosphatase enzyme activities and on the amount of mucosal malonyldialdehyde in broiler chickens

    Directory of Open Access Journals (Sweden)

    Seyed Hamid Farrokhifar

    2014-12-01

    Full Text Available The effects of dietary vitamin E levels on mucosal maltase and alkaline phosphatase (ALP enzyme activities and on the amount of mucosal malonyldialdehyde (MDA in broiler chickens were studied in the present study. One hundred and eighty of day old male broiler chicks (Ross 308 strain were randomly assigned into five groups, each with three replicates and 12 chicks in each replicate. Chickens in group A were fed corn-soy- based diet, while those in groups B, C, D and E were fed the same diet with 20, 60, 180, and 540 mg kg-1 vitamin E supplement (d-alpha tocopherol, respectively. Six birds were randomly chosen from each group, and were euthanized on days 10, 21, 32, and 42 of age. One segment of small intestine outset was homo-genized and mucosal ALP and maltase activity were measured. Moreover, mucosal lipid peroxidate amount was measured to reveal the impact of vitamin E on oxidative stress. Maltase activity was increased with the increase of vitamin E up to 60 mg kg-1 of diet while with further levels, it was decreased. Addition of 60 mg kg-1 of vitamin E to the diet significantly increased ALP enzyme activity (p ≤ 0.001. Addition of 540 mg kg-1 of vitamin E supplement to the diet led to the minimum amount of MDA at 32 days of age. It may be concluded that supplementation of broiler's diet with 60 mg kg-1of vitamin E can increase mucosal maltase and ALP enzyme activity.

  2. New dammarane-type triterpenoids from the leaves of Panax notoginseng and their protein tyrosine phosphatase 1B inhibitory activity

    Directory of Open Access Journals (Sweden)

    Dawei Li

    2014-01-01

    Results and Conclusion: Three new dammarane-type triterpenoids, notoginsenoside-LX (1, notoginsenoside-LY (2, and notoginsenoside-FZ (3 together with eighteen known compounds were isolated from the Panax notoginseng leaves. The structure-activity relationship of the compounds with dammarane-type triterpenoids and their PTP1B inhibitory activity were also reported. Results showed that compounds 2, 15, 20, and 21 can significantly inhibit the enzyme activity of PTP1B in a dose-dependent manner, with inhibitory concentration 50 (IC50 values of 29.08 μM, 21.27 μM, 28.12 μM, and 26.59 μM, respectively. The results suggested that Panax notoginseng leaves might have potential as a new therapeutic agent for the treatment of diabetes.

  3. Short-term variation in extracellular phosphatase activity: Possible limitations for diagnosis of nutrient status in particular algal populations

    Czech Academy of Sciences Publication Activity Database

    Štrojsová, A.; Vrba, Jaroslav

    2009-01-01

    Roč. 43, č. 1 (2009), s. 19-25 ISSN 1386-2588 R&D Projects: GA AV ČR(CZ) IAA6017202 Institutional research plan: CEZ:AV0Z60170517 Keywords : ELF97 phosphate * ectoenzyme activity * diurnal * Ankyra ancora * Chlorogonium fusiforme * Monoraphidium dybowski Subject RIV: EH - Ecology, Behaviour Impact factor: 1.549, year: 2009

  4. New 5-deoxyflavonoids and their inhibitory effects on protein tyrosine phosphatase 1B (PTP1B) activity

    DEFF Research Database (Denmark)

    Nguyen, Phi Hung; Dao, Trong Tuan; Kim, Jayeon

    2011-01-01

    , MS, CD, 1D- and 2D-NMR) and physicochemical analyses. All isolates exhibited moderate inhibitory effects on the enzyme assay with IC₅₀ values ranging from 14.9 ± 1.6 to 98.1 ± 11.3 μM. Compounds with prenyl and methoxy groups in the B ring (1, 2, 4, 8, and 13) possessed strong activity (IC(50) 14...

  5. Ginkgolic Acid C 17:1, Derived from Ginkgo biloba Leaves, Suppresses Constitutive and Inducible STAT3 Activation through Induction of PTEN and SHP-1 Tyrosine Phosphatase

    Directory of Open Access Journals (Sweden)

    Seung Ho Baek

    2017-02-01

    Full Text Available Ginkgolic acid C 17:1 (GAC 17:1 extracted from Ginkgo biloba leaves, has been previously reported to exhibit diverse antitumor effect(s through modulation of several molecular targets in tumor cells, however the detailed mechanism(s of its actions still remains to be elucidated. Signal transducer and activator of transcription 3 (STAT3 is an oncogenic transcription factor that regulates various critical functions involved in progression of diverse hematological malignancies, including multiple myeloma, therefore attenuating STAT3 activation may have a potential in cancer therapy. We determined the anti-tumor mechanism of GAC 17:1 with respect to its effect on STAT3 signaling pathway in multiple myeloma cell lines. We found that GAC 17:1 can inhibit constitutive activation of STAT3 through the abrogation of upstream JAK2, Src but not of JAK1 kinases in U266 cells and also found that GAC can suppress IL-6-induced STAT3 phosphorylation in MM.1S cells. Treatment of protein tyrosine phosphatase (PTP inhibitor blocked suppression of STAT3 phosphorylation by GAC 17:1, thereby indicating a critical role for a PTP. We also demonstrate that GAC 17:1 can induce the substantial expression of PTEN and SHP-1 at both protein and mRNA level. Further, deletion of PTEN and SHP-1 genes by siRNA can repress the induction of PTEN and SHP-1, as well as abolished the inhibitory effect of drug on STAT3 phosphorylation. GAC 17:1 down-regulated the expression of STAT3 regulated gene products and induced apoptosis of tumor cells. Overall, GAC 17:1 was found to abrogate STAT3 signaling pathway and thus exert its anticancer effects against multiple myeloma cells.

  6. Protein-tyrosine Phosphatase SHP2 Contributes to GDNF Neurotrophic Activity through Direct Binding to Phospho-Tyr687 in the RET Receptor Tyrosine Kinase*

    Science.gov (United States)

    Perrinjaquet, Maurice; Vilar, Marçal; Ibáñez, Carlos F.

    2010-01-01

    The signaling mechanisms by which neurotrophic receptors regulate neuronal survival and axonal growth are still incompletely understood. In the receptor tyrosine kinase RET, a receptor for GDNF (glial cell line-derived neurotrophic factor), the functions of the majority of tyrosine residues that become phosphorylated are still unknown. Here we have identified the protein-tyrosine phosphatase SHP2 as a novel direct interactor of RET and the first effector known to bind to phosphorylated Tyr687 in the juxtamembrane region of the receptor. We show that SHP2 is recruited to RET upon ligand binding in a cooperative fashion, such that both interaction with Tyr687 and association with components of the Tyr1062 signaling complex are required for stable recruitment of SHP2 to the receptor. SHP2 recruitment contributes to the ability of RET to activate the PI3K/AKT pathway and promote survival and neurite outgrowth in primary neurons. Furthermore, we find that activation of protein kinase A (PKA) by forskolin reduces the recruitment of SHP2 to RET and negatively affects ligand-mediated neurite outgrowth. In agreement with this, mutation of Ser696, a known PKA phosphorylation site in RET, enhances SHP2 binding to the receptor and eliminates the effect of forskolin on ligand-induced outgrowth. Together, these findings establish SHP2 as a novel positive regulator of the neurotrophic activities of RET and reveal Tyr687 as a critical platform for integration of RET and PKA signals. We anticipate that several other phosphotyrosines of unknown function in neuronal receptor tyrosine kinases will also support similar regulatory functions. PMID:20682772

  7. Protein-tyrosine phosphatase SHP2 contributes to GDNF neurotrophic activity through direct binding to phospho-Tyr687 in the RET receptor tyrosine kinase.

    Science.gov (United States)

    Perrinjaquet, Maurice; Vilar, Marçal; Ibáñez, Carlos F

    2010-10-08

    The signaling mechanisms by which neurotrophic receptors regulate neuronal survival and axonal growth are still incompletely understood. In the receptor tyrosine kinase RET, a receptor for GDNF (glial cell line-derived neurotrophic factor), the functions of the majority of tyrosine residues that become phosphorylated are still unknown. Here we have identified the protein-tyrosine phosphatase SHP2 as a novel direct interactor of RET and the first effector known to bind to phosphorylated Tyr(687) in the juxtamembrane region of the receptor. We show that SHP2 is recruited to RET upon ligand binding in a cooperative fashion, such that both interaction with Tyr(687) and association with components of the Tyr(1062) signaling complex are required for stable recruitment of SHP2 to the receptor. SHP2 recruitment contributes to the ability of RET to activate the PI3K/AKT pathway and promote survival and neurite outgrowth in primary neurons. Furthermore, we find that activation of protein kinase A (PKA) by forskolin reduces the recruitment of SHP2 to RET and negatively affects ligand-mediated neurite outgrowth. In agreement with this, mutation of Ser(696), a known PKA phosphorylation site in RET, enhances SHP2 binding to the receptor and eliminates the effect of forskolin on ligand-induced outgrowth. Together, these findings establish SHP2 as a novel positive regulator of the neurotrophic activities of RET and reveal Tyr(687) as a critical platform for integration of RET and PKA signals. We anticipate that several other phosphotyrosines of unknown function in neuronal receptor tyrosine kinases will also support similar regulatory functions.

  8. Extracellular phosphatase activity of freshwater phytoplankton exposed to different .i.in situ./i. phosphorus concentrations

    Czech Academy of Sciences Publication Activity Database

    Štrojsová, Alena; Vrba, Jaroslav; Nedoma, Jiří; Šimek, Karel

    2005-01-01

    Roč. 56, č. 4 (2005), s. 417-424 ISSN 1323-1650. [Symposium for European Freshwater Sciences /4./. Krakow, 22.08.2005-26.08.2005] R&D Projects: GA ČR(CZ) GA206/02/0003; GA AV ČR(CZ) IAA6017202 Grant - others:FRVŠ(CZ) G4 1841 Institutional research plan: CEZ:AV0Z60170517 Keywords : ELF97 phosphate * image cytometry * species-specific activity Subject RIV: EH - Ecology, Behaviour Impact factor: 1.478, year: 2005

  9. Alkaline phosphatase activity at the southwest coast of India: A comparison of locations differently affected by upwelling..

    Digital Repository Service at National Institute of Oceanography (India)

    Mamatha, S.S.; Malik, A.; Varik, S.; Parvathi, V.; Jineesh, V.K.; Gauns, M.; LokaBharathi, P.A.

    , 2006; Kobori and Taga, 1979; Liu et al., 2010; Nausch, 1998; Ruttenberg and Dyhrman, 2005). Measurement of AP activity (APA) is done by addition of artificial substrates like para-nitrophenol phosphate (pNPP) to samples. The ester... producing bacteria (PPB) were enumerated by most probable numbers (PPB-MPN) by microtitre plate method using para-nitrophenol phosphate (pNPP) as substrate (1 mM) as detailed in section 2.7. The samples were incubated in the dark at room temperature (28...

  10. Glycogen storage disease type Ia mice with less than 2% of normal hepatic glucose-6-phosphataseactivity restored are at risk of developing hepatic tumors.

    Science.gov (United States)

    Kim, Goo-Young; Lee, Young Mok; Kwon, Joon Hyun; Cho, Jun-Ho; Pan, Chi-Jiunn; Starost, Matthew F; Mansfield, Brian C; Chou, Janice Y

    2017-03-01

    Glycogen storage disease type Ia (GSD-Ia), characterized by impaired glucose homeostasis and chronic risk of hepatocellular adenoma (HCA) and carcinoma (HCC), is caused by a deficiency in glucose-6-phosphatase-α (G6Pase-α or G6PC). We have previously shown that G6pc-/- mice receiving gene transfer mediated by rAAV-G6PC, a recombinant adeno-associated virus (rAAV) vector expressing G6Pase-α, and expressing 3-63% of normal hepatic G6Pase-α activity maintain glucose homeostasis and do not develop HCA/HCC. However, the threshold of hepatic G6Pase-α activity required to prevent tumor formation remained unknown. In this study, we constructed rAAV-co-G6PC, a rAAV vector expressing a codon-optimized (co) G6Pase-α and showed that rAAV-co-G6PC was more efficacious than rAAV-G6PC in directing hepatic G6Pase-α expression. Over an 88-week study, we showed that both rAAV-G6PC- and rAAV-co-G6PC-treated G6pc-/- mice expressing 3-33% of normal hepatic G6Pase-α activity (AAV mice) maintained glucose homeostasis, lacked HCA/HCC, and were protected against age-related obesity and insulin resistance. Of the eleven rAAV-G6PC/rAAV-co-G6PC-treated G6pc-/- mice harboring 0.9-2.4% of normal hepatic G6Pase-α activity (AAV-low mice), 3 expressing 0.9-1.3% of normal hepatic G6Pase-α activity developed HCA/HCC, while 8 did not (AAV-low-NT). Finally, we showed that the AAV-low-NT mice exhibited a phenotype indistinguishable from that of AAV mice expressing ≥3% of normal hepatic G6Pase-α activity. The results establish the threshold of hepatic G6Pase-α activity required to prevent HCA/HCC and show that GSD-Ia mice harboring <2% of normal hepatic G6Pase-α activity are at risk of tumor development. Published by Elsevier Inc.

  11. Active micromixer using surface acoustic wave streaming

    Science.gov (United States)

    Branch,; Darren W. , Meyer; Grant D. , Craighead; Harold, G [Ithaca, NY

    2011-05-17

    An active micromixer uses a surface acoustic wave, preferably a Rayleigh wave, propagating on a piezoelectric substrate to induce acoustic streaming in a fluid in a microfluidic channel. The surface acoustic wave can be generated by applying an RF excitation signal to at least one interdigital transducer on the piezoelectric substrate. The active micromixer can rapidly mix quiescent fluids or laminar streams in low Reynolds number flows. The active micromixer has no moving parts (other than the SAW transducer) and is, therefore, more reliable, less damaging to sensitive fluids, and less susceptible to fouling and channel clogging than other types of active and passive micromixers. The active micromixer is adaptable to a wide range of geometries, can be easily fabricated, and can be integrated in a microfluidic system, reducing dead volume. Finally, the active micromixer has on-demand on/off mixing capability and can be operated at low power.

  12. Phosphoprotein phosphatase in the central nervous system of Manduca sexta.

    Science.gov (United States)

    Albin, E E; Newburgh, R W

    1975-02-19

    The existence and some enzymological properties of phosphoprotein phosphatase (EC 3.1.3.16) have been established in the larval central nervous system of the tobacco hornworm, Manduca sexta (Lepidoptera: Sphingidae). A simple, sensitive and reproducible assay employing 32-P-labeled protamine as a phosphoprotein substrate was employed to measure phosphatase activity in both soluble and particulate fractions of the insect nerve cord. The specific activity of soluble phosphatase in the Manduca sexta central nervous system is of the same order of magnitude as that in mammalian brain. Nerve cord phosphoprotamine phosphatase activity may be stimulated by a variety of monovalent salts, the optimal concentration of NaCl or KCl being 0.2 molar. Activity does not appear to be dependent on bivalent metals and is stimulated by EDTA. A reduced sulfhydryl group is obligatory for maximum activity. Phosphatase could be greatly inhibited by sodium fluoride, ATP and GTP. Cyclic AMP and cyclic GMP are without effect on enzyme activity. Although most of the phosphatase activity in the insect nerve cord appears to be of cytosolic origin, much latent activity can be unmasked by incubating membranous fractions with Triton X-100. In contrast to soluble phosphatase, the detergent-solubilized activity is moderately stimulated by Mn-2+.?

  13. Evaluation of Milk Trace Elements, Lactate Dehydrogenase, Alkaline Phosphatase and Aspartate Aminotransferase Activity of Subclinical Mastitis as and Indicator of Subclinical Mastitis in Riverine Buffalo (

    Directory of Open Access Journals (Sweden)

    Anirban Guha

    2012-03-01

    Full Text Available Mastitis is a highly morbid disease that requires detection at the subclinical stage. Tropical countries like India mainly depend on milch buffaloes for milk. The present study was conducted to investigate whether the trace minerals viz. copper (Cu, iron (Fe, zinc (Zn, cobalt (Co and manganese (Mn and enzyme activity of lactate dehydrogenase (LDH, alkaline phosphatase (ALP and aspartate aminotransferase (AST in riverine buffalo milk can be used as an indicator of subclinical mastitis (SCM with the aim of developing suitable diagnostic kit for SCM. Trace elements and enzyme activity in milk were estimated with Atomic absorption Spectrophotometer, GBC 932 plus and biochemical methods, respectively. Somatic cell count (SCC was done microscopically. The cultural examination revealed Gram positive bacteria as the most prevalent etiological agent. A statistically significant (p<0.01 increase in SCC, Fe, Zn, Co and LDH occurred in SCM milk containing gram positive bacterial agents only. ALP was found to be elevated in milk infected by both gram positive and negative bacteria. The percent sensitivity, specificity and accuracy, predictive values and likelihood ratios were calculated taking bacterial culture examination and SCC≥2×105 cells/ml of milk as the benchmark. Only ALP and Zn, the former being superior, were found to be suitable for diagnosis of SCM irrespective of etiological agents. LDH, Co and Fe can be introduced in the screening programs where Gram positive bacteria are omnipresent. It is recommended that both ALP and Zn be measured together in milk to diagnose buffalo SCM, irrespective of etiology.

  14. Mitogen activated protein kinase 6 and MAP kinase phosphatase 1 are involved in the response of Arabidopsis roots to L-glutamate.

    Science.gov (United States)

    López-Bucio, Jesús Salvador; Raya-González, Javier; Ravelo-Ortega, Gustavo; Ruiz-Herrera, León Francisco; Ramos-Vega, Maricela; León, Patricia; López-Bucio, José; Guevara-García, Ángel Arturo

    2018-03-01

    The function and components of L-glutamate signaling pathways in plants have just begun to be elucidated. Here, using a combination of genetic and biochemical strategies, we demonstrated that a MAPK module is involved in the control of root developmental responses to this amino acid. Root system architecture plays an essential role in plant adaptation to biotic and abiotic factors via adjusting signal transduction and gene expression. L-Glutamate (L-Glu), an amino acid with neurotransmitter functions in animals, inhibits root growth, but the underlying genetic mechanisms are poorly understood. Through a combination of genetic analysis, in-gel kinase assays, detailed cell elongation and division measurements and confocal analysis of expression of auxin, quiescent center and stem cell niche related genes, the critical roles of L-Glu in primary root growth acting through the mitogen-activated protein kinase 6 (MPK6) and the dual specificity serine-threonine-tyrosine phosphatase MKP1 could be revealed. In-gel phosphorylation assays revealed a rapid and dose-dependent induction of MPK6 and MPK3 activities in wild-type Arabidopsis seedlings in response to L-Glu. Mutations in MPK6 or MKP1 reduced or increased root cell division and elongation in response to L-Glu, possibly modulating auxin transport and/or response, but in a PLETHORA1 and 2 independent manner. Our data highlight MPK6 and MKP1 as components of an L-Glu pathway linking the auxin response, and cell division for primary root growth.

  15. Enzyme kinetic characterization of protein tyrosine phosphatases

    DEFF Research Database (Denmark)

    Peters, Günther H.J.; Branner, S.; Møller, K. B.

    2003-01-01

    Protein tyrosine phosphatases (PTPs) play a central role in cellular signaling processes, resulting in an increased interest in modulating the activities of PTPs. We therefore decided to undertake a detailed enzyme kinetic evaluation of various transmembrane and cytosolic PTPs (PTPalpha, PTPbeta...

  16. Correlations between calcineurin phosphatase inhibition and cyclosporine metabolites concentrations in kidney transplant recipients: implications for immunoassays

    DEFF Research Database (Denmark)

    Karamperis, N; Koefoed-Nielsen, PB; Brahe, P

    2006-01-01

    by the enzyme multiplied immunoassay technique (EMIT) and by the polyclonal fluorescence polarization immunoassay (pFPIA). Calcineurin phosphatase activity was measured by its ability to dephosphorylate a previously phosphorylated 19-amino acid peptide. We found that calcineurin phosphatase inhibition...... by inhibiting the enzyme calcineurin phosphatase. Determination of the enzyme's activity is one of the most promising pharmacodynamic markers. It is unknown how calcineurin phosphatase inhibition correlates with various cyclosporine monitoring assays and what is the potential impact of metabolites...

  17. Negative Feed-forward Control of Tumor Necrosis Factor (TNF) by Tristetraprolin (ZFP36) Is Limited by the Mitogen-activated Protein Kinase Phosphatase, Dual-specificity Phosphatase 1 (DUSP1)

    Science.gov (United States)

    Shah, Suharsh; Mostafa, Mahmoud M.; McWhae, Andrew; Traves, Suzanne L.; Newton, Robert

    2016-01-01

    TNF is central to inflammation and may play a role in the pathogenesis of asthma. The 3′-untranslated region of the TNF transcript contains AU-rich elements (AREs) that are targeted by the RNA-binding protein, tristetraprolin (also known as zinc finger protein 36 (ZFP36)), which is itself up-regulated by inflammatory stimuli, to promote mRNA degradation. Using primary human bronchial epithelial and pulmonary epithelial A549 cells, we confirm that interleukin-1β (IL1B) induces expression of dual-specificity phosphatase 1 (DUSP1), ZFP36, and TNF. Whereas IL1B-induced DUSP1 is involved in feedback control of MAPK pathways, ZFP36 exerts negative (incoherent) feed-forward control of TNF mRNA and protein expression. DUSP1 silencing increased IL1B-induced ZFP36 expression at 2 h and profoundly repressed TNF mRNA at 6 h. This was partly due to increased TNF mRNA degradation, an effect that was reduced by ZFP36 silencing. This confirms a regulatory network, whereby DUSP1-dependent negative feedback control reduces feed-forward control by ZFP36. Conversely, whereas DUSP1 overexpression and inhibition of MAPKs prevented IL1B-induced expression of ZFP36, this was associated with increased TNF mRNA expression at 6 h, an effect that was predominantly due to elevated transcription. This points to MAPK-dependent feed-forward control of TNF involving ZFP36-dependent and -independent mechanisms. In terms of repression by dexamethasone, neither silencing of DUSP1, silencing of ZFP36, nor silencing of both together prevented the repression of IL1B-induced TNF expression, thereby demonstrating the need for further repressive mechanisms by anti-inflammatory glucocorticoids. In summary, these data illustrate why understanding the competing effects of feedback and feed-forward control is relevant to the development of novel anti-inflammatory therapies. PMID:26546680

  18. Technical activities, 1990: Surface Science Division

    International Nuclear Information System (INIS)

    Powell, C.J.

    1991-05-01

    The report summarizes technical activities and accomplishments of the NIST Surface Science Division during Fiscal Year 1990. Overviews are presented of the Division and of its three constituent groups: Surface Dynamical Processes, Thin Films and Interfaces, and Surface Spectroscopies and Standards. These overviews are followed by reports of selected technical accomplishments during the year. A summary is given of Division outputs and interactions that includes lists of publications, talks, committee assignments, seminars (including both Division seminars and Interface Science seminars arranged through the Division), conferences organized, and a standard reference material certified. Finally, lists are given of Division staff and of guest scientists who have worked in the Division during the past year

  19. JCMT active surface control system: implementation

    Science.gov (United States)

    Smith, Ian A.

    1998-05-01

    The James Clerk Maxwell Telescope on the summit of Mauna Kea in Hawaii is a 15 meter sub-millimeter telescope which operates in the 350 microns to 2 millimeter region. The primary antenna surface consists of 276 panels, each of which is positioned by 3 stepper motors. In order to achieve the highest possible surface accuracy we are embarking upon a project to actively control the position of the panels adjuster system is based on a 6809 micro connected to the control computer by a GPIB interface. This system is slow and inflexible and it would prove difficult to build an active surface control system with it. Part of the upgrade project is to replace the existing micro with a 68060 VME micro. The poster paper will describe how the temperature of the antenna is monitored with the new system, how a Finite Element Analyses package transforms temperature changes into a series of panel adjuster moves, and how these moves are then applied to the surface. The FEA package will run on a high end Sun workstation. A series of DRAMA tasks distributed between the workstation and the Baja 68060 VxWorks Active Surface Control System micro will control the temperature monitoring, FEA and panel adjustment activities. Users can interact with the system via a Tcl/TK based GUI.

  20. Long-acting β2-agonists increase fluticasone propionate-induced mitogen-activated protein kinase phosphatase 1 (MKP-1 in airway smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Melanie Manetsch

    Full Text Available Mitogen-activated protein kinase phosphatase 1 (MKP-1 represses MAPK-driven signalling and plays an important anti-inflammatory role in asthma and airway remodelling. Although MKP-1 is corticosteroid-responsive and increased by cAMP-mediated signalling, the upregulation of this critical anti-inflammatory protein by long-acting β2-agonists and clinically-used corticosteroids has been incompletely examined to date. To address this, we investigated MKP-1 gene expression and protein upregulation induced by two long-acting β2-agonists (salmeterol and formoterol, alone or in combination with the corticosteroid fluticasone propionate (abbreviated as fluticasone in primary human airway smooth muscle (ASM cells in vitro. β2-agonists increased MKP-1 protein in a rapid but transient manner, while fluticasone induced sustained upregulation. Together, long-acting β2-agonists increased fluticasone-induced MKP-1 and modulated ASM synthetic function (measured by interleukin 6 (IL-6 and interleukin 8 (IL-8 secretion. As IL-6 expression (like MKP-1 is cAMP/adenylate cyclase-mediated, the long-acting β2-agonist formoterol increased IL-6 mRNA expression and secretion. Nevertheless, when added in combination with fluticasone, β2-agonists significantly repressed IL-6 secretion induced by tumour necrosis factor α (TNFα. Conversely, as IL-8 is not cAMP-responsive, β2-agonists significantly inhibited TNFα-induced IL-8 in combination with fluticasone, where fluticasone alone was without repressive effect. In summary, long-acting β2-agonists increase fluticasone-induced MKP-1 in ASM cells and repress synthetic function of this immunomodulatory airway cell type.

  1. Negative Feed-forward Control of Tumor Necrosis Factor (TNF) by Tristetraprolin (ZFP36) Is Limited by the Mitogen-activated Protein Kinase Phosphatase, Dual-specificity Phosphatase 1 (DUSP1): IMPLICATIONS FOR REGULATION BY GLUCOCORTICOIDS.

    Science.gov (United States)

    Shah, Suharsh; Mostafa, Mahmoud M; McWhae, Andrew; Traves, Suzanne L; Newton, Robert

    2016-01-01

    TNF is central to inflammation and may play a role in the pathogenesis of asthma. The 3'-untranslated region of the TNF transcript contains AU-rich elements (AREs) that are targeted by the RNA-binding protein, tristetraprolin (also known as zinc finger protein 36 (ZFP36)), which is itself up-regulated by inflammatory stimuli, to promote mRNA degradation. Using primary human bronchial epithelial and pulmonary epithelial A549 cells, we confirm that interleukin-1β (IL1B) induces expression of dual-specificity phosphatase 1 (DUSP1), ZFP36, and TNF. Whereas IL1B-induced DUSP1 is involved in feedback control of MAPK pathways, ZFP36 exerts negative (incoherent) feed-forward control of TNF mRNA and protein expression. DUSP1 silencing increased IL1B-induced ZFP36 expression at 2 h and profoundly repressed TNF mRNA at 6 h. This was partly due to increased TNF mRNA degradation, an effect that was reduced by ZFP36 silencing. This confirms a regulatory network, whereby DUSP1-dependent negative feedback control reduces feed-forward control by ZFP36. Conversely, whereas DUSP1 overexpression and inhibition of MAPKs prevented IL1B-induced expression of ZFP36, this was associated with increased TNF mRNA expression at 6 h, an effect that was predominantly due to elevated transcription. This points to MAPK-dependent feed-forward control of TNF involving ZFP36-dependent and -independent mechanisms. In terms of repression by dexamethasone, neither silencing of DUSP1, silencing of ZFP36, nor silencing of both together prevented the repression of IL1B-induced TNF expression, thereby demonstrating the need for further repressive mechanisms by anti-inflammatory glucocorticoids. In summary, these data illustrate why understanding the competing effects of feedback and feed-forward control is relevant to the development of novel anti-inflammatory therapies. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Mineral nutrient uptake from prey and glandular phosphatase activity as dual test of carnivory in semidesert plants with glandular leaves suspected of carnivory

    Czech Academy of Sciences Publication Activity Database

    Plachno, B.J.; Adamec, Lubomír; Huet, H.

    2009-01-01

    Roč. 104, č. 4 (2009), s. 649-654 ISSN 0305-7364 Institutional research plan: CEZ:AV0Z60050516 Keywords : mineral nutrient uptake * phosphatases * glandular leaves Subject RIV: EF - Botanics Impact factor: 3.501, year: 2009

  3. Detection of extracellular phosphatase activity at the single-cell level by Enzyme-Labeled Fluorescence and flow cytometry: The importance of time kinetics in ELFA labeling

    Czech Academy of Sciences Publication Activity Database

    Duhamel, S.; Gregori, G.; Van Wambeke, F.; Nedoma, Jiří

    75A, č. 2 (2009), s. 163-168 ISSN 1552-4922 Grant - others:MŠMT(CZ) PAI Barrande 2005-06-009-01 Institutional research plan: CEZ:AV0Z60170517 Keywords : alkaline phosphatase * ELF phosphate * heterotrophic bacteria Subject RIV: DA - Hydrology ; Limnology Impact factor: 3.032, year: 2009

  4. Impaired PTPN13 phosphatase activity in spontaneous or HPV-induced squamous cell carcinomas potentiates oncogene signaling through the MAP kinase pathway.

    NARCIS (Netherlands)

    Hoover, A.C.; Strand, G.L.; Nowicki, P.N.; Anderson, M.E.; Vermeer, P.D.; Klingelhutz, A.J.; Bossler, A.D.; Pottala, J.V.; Hendriks, W.J.A.J.; Lee, J.H.

    2009-01-01

    Human papillomaviruses (HPVs) are a causative factor in over 90% of cervical and 25% of head and neck squamous cell carcinomas (HNSCCs). The C terminus of the high-risk HPV 16 E6 oncoprotein physically associates with and degrades a non-receptor protein tyrosine phosphatase (PTPN13), and PTPN13 loss

  5. The phosphatase activity of the isolated H4-H5 loop of Na+/K+ ATPase resides outside its ATP binding site

    Czech Academy of Sciences Publication Activity Database

    Ettrich, Rüdiger

    2004-01-01

    Roč. 271, č. 19 (2004), s. 3923-3939 ISSN 0014-2956 Institutional research plan: CEZ:AV0Z5011922; MSM113100003 Keywords : phosphatase Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.260, year: 2004

  6. Bactericidal activity of biomimetic diamond nanocone surfaces.

    Science.gov (United States)

    Fisher, Leanne E; Yang, Yang; Yuen, Muk-Fung; Zhang, Wenjun; Nobbs, Angela H; Su, Bo

    2016-03-17

    The formation of biofilms on implant surfaces and the subsequent development of medical device-associated infections are difficult to resolve and can cause considerable morbidity to the patient. Over the past decade, there has been growing recognition that physical cues, such as surface topography, can regulate biological responses and possess bactericidal activity. In this study, diamond nanocone-patterned surfaces, representing biomimetic analogs of the naturally bactericidal cicada fly wing, were fabricated using microwave plasma chemical vapor deposition, followed by bias-assisted reactive ion etching. Two structurally distinct nanocone surfaces were produced, characterized, and the bactericidal ability examined. The sharp diamond nanocone features were found to have bactericidal capabilities with the surface possessing the more varying cone dimension, nonuniform array, and decreased density, showing enhanced bactericidal ability over the more uniform, highly dense nanocone surface. Future research will focus on using the fabrication process to tailor surface nanotopographies on clinically relevant materials that promote both effective killing of a broader range of microorganisms and the desired mammalian cell response. This study serves to introduce a technology that may launch a new and innovative direction in the design of biomaterials with capacity to reduce the risk of medical device-associated infections.

  7. Activation of interfacial enzymes at membrane surfaces

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Andresen, Thomas Lars; Halperin, Avi

    2006-01-01

    A host of water-soluble enzymes are active at membrane surfaces and in association with membranes. Some of these enzymes are involved in signalling and in modification and remodelling of the membranes. A special class of enzymes, the phospholipases, and in particular secretory phospholipase A2 (s...

  8. Plasma-Surface Interaction Activities in KSTAR

    NARCIS (Netherlands)

    Hong, S. H.; Yu, Y.; Kim, K. P.; Bak, J. G.; Park, H. J.; Oh, Y. S.; Chung, J.; Nam, Y. U.; Bang, E. N.; Kim, K. R.; Litnovsky, A.; Hellwig, M.; Matveev, D.; Komm, M.; van den Berg, M. A.; Kim, W. C.; Kim, H. K.; Rho, T. H.; Chu, Y.; Oh, Y. K.; Yang, H. L.; Park, K. R.; Chung, K. S.; Kstar Team,

    2013-01-01

    Selected topics of Plasma-Surface Interaction (PSI) activities in KSTAR are briefly introduced. SOL parameter measurements, particle balance and fuel retention, in-vessel dust research, and finally tungsten R & D are discussed. Some quantitative numbers from the initial phase of the operation

  9. Mechanotransductive surfaces for reversible biocatalysis activation

    Science.gov (United States)

    Mertz, Damien; Vogt, Cédric; Hemmerlé, Joseph; Mutterer, Jérôme; Ball, Vincent; Voegel, Jean-Claude; Schaaf, Pierre; Lavalle, Philippe

    2009-09-01

    Fibronectin, like other proteins involved in mechanotransduction, has the ability to exhibit recognition sites under mechanical stretch. Such cryptic sites are buried inside the protein structure in the native fold and become exposed under an applied force, thereby activating specific signalling pathways. Here, we report the design of new active polymeric nanoassembled surfaces that show some similarities to these cryptic sites. These nanoassemblies consist of a first polyelectrolyte multilayer stratum loaded with enzymes and capped with a second polyelectrolyte multilayer acting as a mechanically sensitive nanobarrier. The biocatalytic activity of the film is switched on/off reversibly by mechanical stretching, which exposes enzymes through the capping barrier, similarly to mechanisms involved in proteins during mechanotransduction. This first example of a new class of biologically inspired surfaces should have great potential in the design of various devices aimed to trigger and modulate chemical reactions by mechanical action with applications in the field of microfluidic devices or mechanically controlled biopatches for example.

  10. Active colloidal propulsion over a crystalline surface

    Science.gov (United States)

    Choudhury, Udit; Straube, Arthur V.; Fischer, Peer; Gibbs, John G.; Höfling, Felix

    2017-12-01

    We study both experimentally and theoretically the dynamics of chemically self-propelled Janus colloids moving atop a two-dimensional crystalline surface. The surface is a hexagonally close-packed monolayer of colloidal particles of the same size as the mobile one. The dynamics of the self-propelled colloid reflects the competition between hindered diffusion due to the periodic surface and enhanced diffusion due to active motion. Which contribution dominates depends on the propulsion strength, which can be systematically tuned by changing the concentration of a chemical fuel. The mean-square displacements (MSDs) obtained from the experiment exhibit enhanced diffusion at long lag times. Our experimental data are consistent with a Langevin model for the effectively two-dimensional translational motion of an active Brownian particle in a periodic potential, combining the confining effects of gravity and the crystalline surface with the free rotational diffusion of the colloid. Approximate analytical predictions are made for the MSD describing the crossover from free Brownian motion at short times to active diffusion at long times. The results are in semi-quantitative agreement with numerical results of a refined Langevin model that treats translational and rotational degrees of freedom on the same footing.

  11. Surface active properties of lipid nanocapsules.

    Directory of Open Access Journals (Sweden)

    Celia R A Mouzouvi

    Full Text Available Lipid nanocapsules (LNCs are biomimetic nanocarriers used for the encapsulation of a broad variety of active ingredients. Similar to surface active compounds, LNCs contain both hydrophilic and hydrophobic parts in their structure. Moreover, the components of LNCs, macrogol 15 hydroxystearate (MHS and lecithin, are known for their surface active properties. Therefore, the aim of this paper was to investigate the capability of the LNCs to decrease surface tension using two techniques: drop tensiometry and the Wilhelmy plate method. LNCs with diameters ranging from 30 to 100 nm were successfully obtained using a phase inversion technique. The LNCs' properties, such as size and zeta potential, depend on the composition. LNCs exhibit a lower limiting surface tension compared to MHS (34.8-35.0 mN/m and 37.7-38.8 mN/m, respectively, as confirmed by both drop tensiometry and the Wilhelmy plate method. LNCs have exhibited a saturated interfacial concentration (SIC that was 10-fold higher than the critical micellar concentration (CMC of MHS or the SIC of binary and ternary mixtures of LNC ingredients. The SIC of the LNC formulations depended on the mass mixing ratio of the MHS/triglycerides but not on the presence of lecithin. The CMC/SIC values measured by the Wilhelmy plate method were higher than those obtained using drop tensiometry because of the longer duration of the tensiometry measurement. In conclusion, the surfactant-like properties of the LNCs offer new possibilities for medical and pharmaceutical applications.

  12. Alzheimer's amyloid precursor protein is expressed on the surface of hematopoietic cells upon activation.

    Science.gov (United States)

    Bullido, M J; Muñoz-Fernandez, M A; Recuero, M; Fresno, M; Valdivieso, F

    1996-08-21

    A4-amyloid is the major component of senile plaques and neurofibrillary tangles found in the brain of patients suffering Alzheimer's disease. This 39-42 amino acid peptide is derived from a larger precursor protein (APP). Since APP gene encodes for a putative membrane protein, the study of APP expression at the cell surface may provide useful data for understanding its physiological function. In this report, we present data on APP expression, that was detected by APP specific mAbs in cells of the hematopoietic system. APP was weakly expressed on the cell surface of resting human lymphocytes and monocytes, but it could be induced to the surface of those cells upon stimulation. The cell activators capable of inducing APP membrane expression comprehended mitogenic lectins, calcium ionophores, phosphatase inhibitors, and anti mu-chain or anti-CD3 antibodies in B and T cells, respectively. Interestingly, phorbol esters were able to induce APP membrane expression in monocytic, but not in lymphoid cells. In contrast to lymphocytes and monocytes, granulocytes never expressed cell surface or cytoplasmic APP, even after the activation. The induction of membrane APP in response to lymphocyte activation signals, including antibodies to the antigen receptor of B and T cells, raises the possibility that APP might play the role of a cell surface receptor in the immune system.

  13. Infrared active thermography for surface layer characterization

    International Nuclear Information System (INIS)

    Semerok, A.; Fomichev, S.; Farcage, D.; Sortais, C.; Courtois, X.

    2006-05-01

    Deposited layer characterization was stated as the main goal of our studies for 2006. The investigations by DRFC/SIPP/GCFP (CEA Cadarache) were performed with the procedure of surface temperature measurements based on infrared thermography with synchronous demodulation (Lock-in Thermography). It was applied to provide the temperature surface monitoring during the modulated heating by illumination. The obtained 2D-cartography revealed the zones with a weak heat transfer resulting from a low layer/surface adhesion or poor layer thermal conductivity. The obtained lock-in cartography data should be regarded only as qualitative. For deposited layers characterization (layer depth, adhesion with the substrate), the active laser pyrometer measurements with the developed experimental device were made in LILM laboratory (CEA Saclay). Active surface pyrometry with repetitive laser heating can provide both qualitative and quantitative data on the first layer and the interface with the substrate. A 3D-numerical model of graphite deposited layer heating by a pulsed high repetition rate laser beam was developed to determine the heated surface temperature with a high temporal and spatial resolution. The theoretical data obtained with 3D-numerical model for surface heating were compared with the experimental results. It was demonstrated that for the given optical and thermo-physical parameters of materials, the theoretical temperatures may be fitted with the experimental results to assess certain unknown parameters of the layer (thermal contact resistance, diffusivity, thickness, porosity, ). Based on the comparison of the obtained experimental and theoretical results, the deposited layer characterization was made. The results of the investigations on Active Laser Pyrometry and Lock-in Thermography demonstrated that the methods can provide qualitative and quantitative data on the deposited layer and on the layer/substrate interface. The correlation and cross-check of the results

  14. Altered alkaline phosphatase activity in obese Zucker rats liver respect to lean Zucker and Wistar rats discussed in terms of all putative roles ascribed to the enzyme

    Directory of Open Access Journals (Sweden)

    V. Bertone

    2011-02-01

    Full Text Available Biliary complications often lead to acute and chronic liver injury after orthotopic liver transplantation (OLT. Bile composition and secretion depend on the integrated action of all the components of the biliary tree, starting from hepatocytes. Fatty livers are often discarded as grafts for OLT, since they are extremely vulnerable to conventional cold storage (CS. However, the insufficiency of donors has stimulated research to improve the usage of such marginal organs as well as grafts. Our group has recently developed a machine perfusion system at subnormothermic temperature (20°C; MP20 that allows a marked improvement in preservation of fatty and even of normal rat livers as compared with CS. We sought to evaluate the response of the biliary tree of fatty liver to MP20, and a suitable marker was essential to this purpose. Alkaline phosphatase (AlkP, EC 3.1.3.1, frequently used as marker of membrane transport in hepatocytes and bile ducts, was our first choice. Since no histochemical data were available on AlkP distribution and activity in fatty liver, we have first settled to investigate AlkP activity in the steatotic liver of fatty Zucker rats (fa/fa, using as controls lean Zucker (fa/+ and normal Wistar rats. The AlkP reaction in Wistar rats was in accordance with the existing data and, in particular, was present in bile canaliculi of hepatocytes in the periportal region and midzone, in the canals of Hering and in small bile ducts but not in large bile ducts. In lean ZR liver the AlkP reaction in Hering canals and small bile ducts was similar to Wistar rat liver but hepatocytes had lower canalicular activity and besides presented moderate basolateral reaction. The difference between lean Zucker and Wistar rats, both phenotypically normal animals, could be related to the fact that lean Zucker rats are genotypically heterozygous for a recessive mutated allele. In fatty liver, the activity in ductules and small bile ducts was unchanged, but

  15. Altered alkaline phosphatase activity in obese Zucker rats liver respect to lean Zucker and Wistar rats discussed in terms of all putative roles ascribed to the enzyme.

    Science.gov (United States)

    Bertone, V; Tarantola, E; Ferrigno, A; Gringeri, E; Barni, S; Vairetti, M; Freitas, I

    2011-02-08

    Biliary complications often lead to acute and chronic liver injury after orthotopic liver transplantation (OLT). Bile composition and secretion depend on the integrated action of all the components of the biliary tree, starting from hepatocytes. Fatty livers are often discarded as grafts for OLT, since they are extremely vulnerable to conventional cold storage (CS). However, the insufficiency of donors has stimulated research to improve the usage of such marginal organs as well as grafts. Our group has recently developed a machine perfusion system at subnormothermic temperature (20°C; MP20) that allows a marked improvement in preservation of fatty and even of normal rat livers as compared with CS. We sought to evaluate the response of the biliary tree of fatty liver to MP20, and a suitable marker was essential to this purpose. Alkaline phosphatase (AlkP, EC 3.1.3.1), frequently used as marker of membrane transport in hepatocytes and bile ducts, was our first choice. Since no histochemical data were available on AlkP distribution and activity in fatty liver, we have first settled to investigate AlkP activity in the steatotic liver of fatty Zucker rats (fa/fa), using as controls lean Zucker (fa/+) and normal Wistar rats. The AlkP reaction in Wistar rats was in accordance with the existing data and, in particular, was present in bile canaliculi of hepatocytes in the periportal region and midzone, in the canals of Hering and in small bile ducts but not in large bile ducts. In lean ZR liver the AlkP reaction in Hering canals and small bile ducts was similar to Wistar rat liver but hepatocytes had lower canalicular activity and besides presented moderate basolateral reaction. The difference between lean Zucker and Wistar rats, both phenotypically normal animals, could be related to the fact that lean Zucker rats are genotypically heterozygous for a recessive mutated allele. In fatty liver, the activity in ductules and small bile ducts was unchanged, but most hepatocytes

  16. Phosphatidylinositol anchor of HeLa cell alkaline phosphatase

    International Nuclear Information System (INIS)

    Jemmerson, R.; Low, M.G.

    1987-01-01

    Alkaline phosphatase from cancer cells, HeLa TCRC-1, was biosynthetically labeled with either 3 H-fatty acids or [ 3 H]ethanolamine as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material. Phosphatidylinositol-specific phospholipase C (PI-PLC) released a substantial proportion of the 3 H-fatty acid label from immunoaffinity-purified alkaline phosphatase but had no effect on the radioactivity of [ 3 H]ethanolamine-labeled material. PI-PLC also liberated catalytically active alkaline phosphatase from viable cells, and this could be selectively blocked by monoclonal antibodies to alkaline phosphatase. However, the alkaline phosphatase released from 3 H-fatty acid labeled cells by PI-PLC was not radioactive. By contrast, treatment with bromelain removed both the 3 H-fatty acid and the [ 3 H]ethanolamine label from purified alkaline phosphatase. Subtilisin was also able to remove the [ 3 H]ethanolamine label from the purified alkaline phosphatase. The 3 H radioactivity in alkaline phosphatase purified from [ 3 H]ethanolamine-labeled cells comigrated with authentic [ 3 H]ethanolamine by anion-exchange chromatography after acid hydrolysis. The data suggest that the 3 H-fatty acid and [ 3 H]ethanolamine are covalently attached to the carboxyl-terminal segment since bromelain and subtilisin both release alkaline phosphatase from the membrane by cleavage at that end of the polypeptide chain. The data are consistent with findings for other proteins recently shown to be anchored in the membrane through a glycosylphosphatidylinositol structure and indicate that a similar structure contributes to the membrane anchoring of alkaline phosphatase

  17. Growth, extracellular alkaline phosphatase activity, and kinetic characteristic responses of the bloom-forming toxic cyanobacterium, Microcystis aeruginosa, to atmospheric particulate matter (PM2.5, PM2.5-10, and PM>10).

    Science.gov (United States)

    Xu, Ziran; Wang, Shoubing; Wang, Yuanan; Zhang, Jie

    2018-03-01

    Atmospheric particulate matter (APM), commonly seen and widely excited in environment, appears great enough to influence the biochemical processes in aquatic microorganisms and phytoplankton. Understanding the response of cyanobacteria to various factors is fundamental for eutrophication control. To clarify the response of cyanobacteria to APM, the effects of PM 2.5 , PM 2.5-10 , and PM >10 on Microcystis aeruginosa were researched. Variabilities in cell density, chlorophyll a, soluble protein, malondialdehyde, extracellular activity, and kinetic parameters of alkaline phosphatase were evaluated by lab-cultured experiments. Results showed that the PM 2.5 had a slight stimulation impact on the growth and enhanced both of the 48- and 72-h extracellular alkaline phosphatase activity (APA), the affinity of alkaline phosphatase for substrate, and the 72-h maximum enzymatic reaction velocity (V max ). Moreover, the stimulations in extracellular APA and V max enhanced with the increasing exposure concentrations. We also found there were no obvious distinctions on the effects of growth and alkaline phosphatase in M. aeruginosa between PM 2.5-10 and PM >10 exposure groups. Obviously, inhibitory effects on growth existed in 4.0 and 8.0 mg/L PM 2.5-10 and 8.0 mg/L PM >10 at 120 h. Furthermore, PM 2.5-10 and PM >10 exerted inhibitory effects on the extracellular APA during the 72-h exposure. Simultaneously, the V max was notably inhibited and the affinity of alkaline phosphatase for substrate was more inseparable compared with control in PM 2.5-10 and PM >10 treatments. Nevertheless, the inhibitors in extracellular APA and kinetic parameters were unrelated to PM 2.5-10 and PM >10 exposure concentrations. Two-way ANOVA results revealed that there were significant interactions between exposure concentration and diameter of APM on the 120-h cell density, soluble protein content, APA, and 72 h APA of M. aeruginosa. These results in our study would be meaningful to further

  18. Manzamenones Inhibit T-Cell Protein Tyrosine Phosphatase

    Directory of Open Access Journals (Sweden)

    Jun'ichi Kobayashi

    2006-02-01

    Full Text Available Abstract: Manzamenones A~C (1~3 and E~F (5~6, unique oxylipin metabolites isolated from a marine sponge Plakortis sp., have been found to exhibit inhibitory activity against Tcell protein tyrosine phosphatase (TCPTP. The inhibitory activity of 2 and 5 against TCPTP was 4 times more potent than that against protein tyrosine phosphatase-1B (PTP1B.

  19. Cloning and Characterization of Secretory Tyrosine Phosphatases of Mycobacterium tuberculosis

    Science.gov (United States)

    Koul, Anil; Choidas, Axel; Treder, Martin; Tyagi, Anil K.; Drlica, Karl; Singh, Yogendra; Ullrich, Axel

    2000-01-01

    Two genes with sequence homology to those encoding protein tyrosine phosphatases were cloned from genomic DNA of Mycobacterium tuberculosis H37Rv. The calculated molecular masses of these two putative tyrosine phosphatases, designated MPtpA and MPtpB, were 17.5 and 30 kDa, respectively. MPtpA and MPtpB were expressed as glutathione S-transferase fusion proteins in Escherichia coli. The affinity-purified proteins dephosphorylated the phosphotyrosine residue of myelin basic protein (MBP), but they failed to dephosphorylate serine/threonine residues of MBP. The activity of these phosphatases was inhibited by sodium orthovanadate, a specific inhibitor of tyrosine phosphatases, but not by okadaic acid, an inhibitor of serine/threonine phosphatases. Mutations at the catalytic site motif, cysteine 11 of MPtpA and cysteine 160 of MPtpB, abolished enzyme activity. Southern blot analysis revealed that, while mptpA is present in slow-growing mycobacterial species as well as fast-growing saprophytes, mptpB was restricted to members of the M. tuberculosis complex. These phosphatases were present in both whole-cell lysates and culture filtrates of M. tuberculosis, suggesting that these proteins are secreted into the extracellular medium. Since tyrosine phosphatases are essential for the virulence of several pathogenic bacteria, the restricted distribution of mptpB makes it a good candidate for a virulence gene of M. tuberculosis. PMID:10986245

  20. Cloning and characterization of secretory tyrosine phosphatases of Mycobacterium tuberculosis.

    Science.gov (United States)

    Koul, A; Choidas, A; Treder, M; Tyagi, A K; Drlica, K; Singh, Y; Ullrich, A

    2000-10-01

    Two genes with sequence homology to those encoding protein tyrosine phosphatases were cloned from genomic DNA of Mycobacterium tuberculosis H(37)Rv. The calculated molecular masses of these two putative tyrosine phosphatases, designated MPtpA and MPtpB, were 17. 5 and 30 kDa, respectively. MPtpA and MPtpB were expressed as glutathione S-transferase fusion proteins in Escherichia coli. The affinity-purified proteins dephosphorylated the phosphotyrosine residue of myelin basic protein (MBP), but they failed to dephosphorylate serine/threonine residues of MBP. The activity of these phosphatases was inhibited by sodium orthovanadate, a specific inhibitor of tyrosine phosphatases, but not by okadaic acid, an inhibitor of serine/threonine phosphatases. Mutations at the catalytic site motif, cysteine 11 of MPtpA and cysteine 160 of MPtpB, abolished enzyme activity. Southern blot analysis revealed that, while mptpA is present in slow-growing mycobacterial species as well as fast-growing saprophytes, mptpB was restricted to members of the M. tuberculosis complex. These phosphatases were present in both whole-cell lysates and culture filtrates of M. tuberculosis, suggesting that these proteins are secreted into the extracellular medium. Since tyrosine phosphatases are essential for the virulence of several pathogenic bacteria, the restricted distribution of mptpB makes it a good candidate for a virulence gene of M. tuberculosis.

  1. Ganglioside contained in the neuronal tissue-enriched acidic protein of 22 kDa (NAP-22) fraction prepared from the detergent-resistant membrane microdomain of rat brain inhibits the phosphatase activity of calcineurin.

    Science.gov (United States)

    Kobayashi, Yuumi; da Silva, Ronan; Kumanogoh, Haruko; Miyata, Shinji; Sato, Chihiro; Kitajima, Ken; Nakamura, Shun; Morita, Mistuhiro; Hayashi, Fumio; Maekawa, Shohei

    2015-09-01

    Neurons have well-developed membrane microdomains called "rafts" that are recovered as a detergent-resistant membrane microdomain fraction (DRM). Neuronal tissue-enriched acidic protein of 22 kDa (NAP-22) is one of the major protein components of neuronal DRM. To determine the cellular function of NAP-22, interacting proteins were screened with an immunoprecipitation assay, and calcineurin (CaN) was detected. Further studies with NAP-22 prepared from DRM and CaN expressed in bacteria showed the binding of these proteins and a dose-dependent inhibitory effect of the NAP-22 fraction on the phosphatase activity of CaN. On the other hand, NAP-22 expressed in bacteria showed low binding to CaN and a weak inhibitory effect on phosphatase activity. To solve this discrepancy, identification of a nonprotein component that modulates CaN activity in the DRM-derived NAP-22 fraction was attempted. After lyophilization, a lipid fraction was extracted with chloroform/methanol. The lipid fraction showed an inhibitory effect on CaN without NAP-22, and further fractionation of the extract with thin-layer chromatography showed the presence of several lipid bands having an inhibitory effect on CaN. The mobility of these bands coincided with that of authentic ganglioside (GM1a, GD1a, GD1b, and GT1b), and authentic ganglioside showed an inhibitory effect on CaN. Treatment of lipid with endoglycoceramidase, which degrades ganglioside to glycochain and ceramide, caused a diminution of the inhibitory effect. These results show that DRM-derived NAP-22 binds several lipids, including ganglioside, and that ganglioside inhibits the phosphatase activity of CaN. © 2015 Wiley Periodicals, Inc.

  2. Purification of acidic phosphatase from mustard seedlings

    OpenAIRE

    sprotocols

    2014-01-01

    ### INTRODUCTION Phosphate esters are widely distributed in any organism. Nucleic acids, metabolic intermediates like glucose-6-phosphate, energy-rich substrates (AMP, creatine phosphate) are some obvious examples. While many metabolic intermediates are activated through the transfer of phosphate groups (e.g., by kinases) it is equally important that phosphate esters can also be rapidly broken down. The hydrolytic removal of phosphate groups from phosphoesters is catalyzed by phosphatases...

  3. Bone Alkaline Phosphatase and Tartrate-Resistant Acid Phosphatase: Potential Co-regulators of Bone Mineralization.

    Science.gov (United States)

    Halling Linder, Cecilia; Ek-Rylander, Barbro; Krumpel, Michael; Norgård, Maria; Narisawa, Sonoko; Millán, José Luis; Andersson, Göran; Magnusson, Per

    2017-07-01

    Phosphorylated osteopontin (OPN) inhibits hydroxyapatite crystal formation and growth, and bone alkaline phosphatase (BALP) promotes extracellular mineralization via the release of inorganic phosphate from the mineralization inhibitor inorganic pyrophosphate (PPi). Tartrate-resistant acid phosphatase (TRAP), produced by osteoclasts, osteoblasts, and osteocytes, exhibits potent phosphatase activity towards OPN; however, its potential capacity as a regulator of mineralization has not previously been addressed. We compared the efficiency of BALP and TRAP towards the endogenous substrates for BALP, i.e., PPi and pyridoxal 5'-phosphate (PLP), and their impact on mineralization in vitro via dephosphorylation of bovine milk OPN. TRAP showed higher phosphatase activity towards phosphorylated OPN and PPi compared to BALP, whereas the activity of TRAP and BALP towards PLP was comparable. Bovine milk OPN could be completely dephosphorylated by TRAP, liberating all its 28 phosphates, whereas BALP dephosphorylated at most 10 phosphates. OPN, dephosphorylated by either BALP or TRAP, showed a partially or completely attenuated phosphorylation-dependent inhibitory capacity, respectively, compared to native OPN on the formation of mineralized nodules. Thus, there are phosphorylations in OPN important for inhibition of mineralization that are removed by TRAP but not by BALP. In conclusion, our data indicate that both BALP and TRAP can alleviate the inhibitory effect of OPN on mineralization, suggesting a potential role for TRAP in skeletal mineralization. Further studies are warranted to explore the possible physiological relevance of TRAP in bone mineralization.

  4. PTEN is a protein tyrosine phosphatase for IRS1.

    Science.gov (United States)

    Shi, Yuji; Wang, Junru; Chandarlapaty, Sarat; Cross, Justin; Thompson, Craig; Rosen, Neal; Jiang, Xuejun

    2014-06-01

    The biological function of the PTEN tumor suppressor is mainly attributed to its lipid phosphatase activity. This study demonstrates that mammalian PTEN is a protein tyrosine phosphatase that selectively dephosphorylates insulin receptor substrate-1 (IRS1), a mediator of insulin and IGF signals. IGF signaling was defective in cells lacking NEDD4, a PTEN ubiquitin ligase, whereas AKT activation triggered by EGF or serum was unimpaired. Defective IGF signaling caused by NEDD4 deletion, including phosphorylation of IRS1 and AKT, was rescued by PTEN ablation. We demonstrate the nature of PTEN as an IRS1 phosphatase by direct biochemical analysis and cellular reconstitution, showing that NEDD4 supports insulin-mediated glucose metabolism and is required for the proliferation of IGF1 receptor-dependent but not EGF receptor-dependent tumor cells. Thus, PTEN is a protein phosphatase for IRS1, and its antagonism by NEDD4 promotes signaling by IGF and insulin.

  5. Intestinal alkaline phosphatase: novel functions and protective effects.

    Science.gov (United States)

    Lallès, Jean-Paul

    2014-02-01

    Important protective roles of intestinal alkaline phosphatase (IAP)--including regulation of intestinal surface pH, absorption of lipids, detoxification of free nucleotides and bacterial lipopolysaccharide, attenuation of intestinal inflammation, and possible modulation of the gut microbiota--have been reviewed recently. IAP is modulated by numerous nutritional factors. The present review highlights new findings on the properties of IAP and extends the list of its protective functions. Critical assessment of data suggests that some IAP properties are a direct result of dephosphorylation of proinflammatory moieties, while others (e.g., gut barrier protection and microbiota shaping) may be secondary to IAP-mediated downregulation of inflammation. IAP and tissue-nonspecific alkaline phosphatase isoforms characterize the small intestine and the colon, respectively. Gastrointestinal administration of exogenous IAP ameliorates gut inflammation and favors gut tissue regeneration, whereas enteral and systemic IAP administration attenuates systemic inflammation only. Finally, the IAP gene family has a strong evolutionary link to food-driven changes in gastrointestinal tract anatomy and microbiota composition. Therefore, stimulation of IAP activity by dietary intervention is a goal for preserving gut homeostasis and health by minimizing low-grade inflammation. © 2013 International Life Sciences Institute.

  6. Multisystemic functions of alkaline phosphatases.

    Science.gov (United States)

    Buchet, René; Millán, José Luis; Magne, David

    2013-01-01

    Human and mouse alkaline phosphatases (AP) are encoded by a multigene family expressed ubiquitously in multiple tissues. Gene knockout (KO) findings have helped define some of the precise exocytic functions of individual isozymes in bone, teeth, the central nervous system, and in the gut. For instance, deficiency in tissue-nonspecific alkaline phosphatase (TNAP) in mice (Alpl (-/-) mice) and humans leads to hypophosphatasia (HPP), an inborn error of metabolism characterized by epileptic seizures in the most severe cases, caused by abnormal metabolism of pyridoxal-5'-phosphate (the predominant form of vitamin B6) and by hypomineralization of the skeleton and teeth featuring rickets and early loss of teeth in children or osteomalacia and dental problems in adults caused by accumulation of inorganic pyrophosphate (PPi). Enzyme replacement therapy with mineral-targeting TNAP prevented all the manifestations of HPP in mice, and clinical trials with this protein therapeutic are showing promising results in rescuing life-threatening HPP in infants. Conversely, TNAP induction in the vasculature during generalized arterial calcification of infancy (GACI), type II diabetes, obesity, and aging can cause medial vascular calcification. TNAP inhibitors, discussed extensively in this book, are in development to prevent pathological arterial calcification. The brush border enzyme intestinal alkaline phosphatase (IAP) plays an important role in fatty acid (FA) absorption, in protecting gut barrier function, and in determining the composition of the gut microbiota via its ability to dephosphorylate lipopolysaccharide (LPS). Knockout mice (Akp3 (-/-)) deficient in duodenal-specific IAP (dIAP) become obese, and develop hyperlipidemia and hepatic steatosis when fed a high-fat diet (HFD). These changes are accompanied by upregulation in the jejunal-ileal expression of the Akp6 IAP isozyme (global IAP, or gIAP) and concomitant upregulation of FAT/CD36, a phosphorylated fatty acid

  7. Calcium-phosphate biomineralization induced by alkaline phosphatase activity in Escherichia coli: localization, kinetics and potential signatures in the fossil record

    Directory of Open Access Journals (Sweden)

    Julie eCosmidis

    2015-12-01

    Full Text Available Bacteria are thought to play an important role in the formation of calcium-phosphate minerals composing marine phosphorites, as supported by the common occurrence of fossil microbes in these rocks. Phosphatase enzymes may play a key role in this process. Indeed, they may increase the supersaturation with respect to Ca-phosphates by releasing orthophosphate ions following hydrolysis of organic phosphorus. However, several questions remain unanswered about the cellular-level mechanisms involved in this model, and its potential signatures in the mineral products. We studied Ca-phosphate precipitation by different strains of Escherichia coli which were genetically modified to differ in the abundance and cellular localization of the alkaline phosphatase (PHO A produced. The mineral precipitated by either E. coli or purified PHO A was invariably identified as a carbonate-free non-stoichiometric hydroxyapatite. However, the bacterial precipitates could be discriminated from the ones formed by purified PHO A at the nano-scale. PHO A localization was shown to influence the pattern of Ca-phosphate nucleation and growth. Finally, the rate of calcification was proved to be consistent with the PHO A enzyme kinetics. Overall, this study provides mechanistic keys to better understand phosphogenesis in the environment, and experimental references to better interpret the microbial fossil record in phosphorites.

  8. Does Titan have an Active Surface?

    Science.gov (United States)

    Nelson, R.

    2009-12-01

    ammonia, a compound expected in Titan’s interior. This, combined with the previous evidence from VIMS and RADAR images, creates a strong case for Titan having a presently active surface, possibly due to cryovolcanism. Cassini encountered Titan at very close range on 2008-11-19-13:58 and again on 2008-12-05-12:38. These epochs are called T47 and T48. Comparison of earlier lower resolution data (T5) with the recent T47 and T48 data reveal changes of the surface reflectance and morphology in the Hotei region. This is the first evidence from VIMS that confirms the RADAR report that Hotei Reggio has morphology consistent with volcanic terrain. It has not escaped our attention that ammonia, in association with methane and nitrogen, the principal species of Titan’s atmosphere, closely replicates the environment at the time that live first emerged on earth. If Titan is currently active then these results raise the following questions: What is the full extent of current geologic activity? What are the ongoing processes? Are Titan’s chemical processes today supporting a prebiotic chemistry similar to that under which life evolved on Earth? This work done at JPL under contract with NASA. Refs: [1]R. M. Nelson et al., Icarus 199 (2009) 429-441. [2]R. M. Nelson et al., GRL, VOL. 36, L04202, doi:10.1029/2008GL036206, 2009. [3]S. D. Wall GRL, VOL. 36, L04203, doi:10.1029/2008GL036415, 2009

  9. The effects of protein phosphatase inhibitors on the duration of central sensitization of rat dorsal horn neurons following injection of capsaicin

    Directory of Open Access Journals (Sweden)

    Fang Li

    2006-07-01

    Full Text Available Abstract Protein kinases and phosphatases catalyze opposing reactions of phosphorylation and dephosphorylation, which may modulate the function of crucial signaling proteins in central nervous system. This is an important mechanism in the regulation of intracellular signal transduction pathways in nociceptive neurons. To explore the role of protein phosphatase in central sensitization of spinal nociceptive neurons following peripheral noxious stimulation, using electrophysiological recording techniques, we investigated the role of two inhibitors of protein phosphatase type 2A (PP2A, fostriecin and okadaic acid (OA, on the responses of dorsal horn neurons to mechanical stimuli in anesthetized rats following intradermal injection of capsaicin. Central sensitization was initiated by injection of capsaicin into the plantar surface of the left paw. A microdialysis fiber was implanted in the spinal cord dorsal horn for perfusion of ACSF and inhibitors of PP2A, fostriecin and okadaic acid. We found that in ACSF pretreated animals, the responses to innocuous and noxious stimuli following capsaicin injection increased over a period of 15 min after injection and had mostly recovered by 60 min later. However, pre- or post-treatment with the phosphatase inhibitors, fostriecin or OA, significantly enhanced the effects of capsaicin injection by prolonging the responses to more than 3 hours. These results confirm that blockade of protein phosphatase activity may potentiate central sensitization of nociceptive transmission in the spinal cord following capsaicin injection and indicate that protein phosphatase type 2A may be involved in determining the duration of capsaicin-induced central sensitization.

  10. Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

    Science.gov (United States)

    Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  11. Surface and interface electronic structure: Three year activity report

    International Nuclear Information System (INIS)

    Kevan, S.D.

    1992-01-01

    The 3-year activity report covers surface structure and phonon anomalies (surface reconstruction on W(001) and Mo(001), adsorbate lateral ordering, surface Fermi contours and phonon anomalies on Pt(111) and Pd(001)), adsorbate vibrational damping, charge transfer in momentum space: W(011)-K, surface states and resonances (relativistic effects ampersand computations, surface resonances)

  12. Localized cranial hyperostosis of meningiomas: a result of neoplastic enzymatic activity?

    DEFF Research Database (Denmark)

    Heick, A.; Mosdal, C.; Klinken, Leif

    1993-01-01

    Neuropathology, alkaline phosphatase, cranial hyperostosis, meningioma, ossifying enzymatic activity......Neuropathology, alkaline phosphatase, cranial hyperostosis, meningioma, ossifying enzymatic activity...

  13. Characterization and site-directed mutagenesis of Wzb, an O-phosphatase from Lactobacillus rhamnosus

    Directory of Open Access Journals (Sweden)

    Gilbert Christophe

    2008-04-01

    Full Text Available Abstract Background Reversible phosphorylation events within a polymerisation complex have been proposed to modulate capsular polysaccharide synthesis in Streptococcus pneumoniae. Similar phosphatase and kinase genes are present in the exopolysaccharide (EPS biosynthesis loci of numerous lactic acid bacteria genomes. Results The protein sequence deduced from the wzb gene in Lactobacillus rhamnosus ATCC 9595 reveals four motifs of the polymerase and histidinol phosphatase (PHP superfamily of prokaryotic O-phosphatases. Native and modified His-tag fusion Wzb proteins were purified from Escherichia coli cultures. Extracts showed phosphatase activity towards tyrosine-containing peptides. The purified fusion protein Wzb was active on p-nitrophenyl-phosphate (pNPP, with an optimal activity in presence of bovine serum albumin (BSA 1% at pH 7.3 and a temperature of 75°C. At 50°C, residual activity decreased to 10 %. Copper ions were essential for phosphatase activity, which was significantly increased by addition of cobalt. Mutated fusion Wzb proteins exhibited reduced phosphatase activity on p-nitrophenyl-phosphate. However, one variant (C6S showed close to 20% increase in phosphatase activity. Conclusion These characteristics reveal significant differences with the manganese-dependent CpsB protein tyrosine phosphatase described for Streptococcus pneumoniae as well as with the polysaccharide-related phosphatases of Gram negative bacteria.

  14. Phosphorylation and activation of nuclear Ca{sup 2+}/calmodulin-dependent protein kinase phosphatase (CaMKP-N/PPM1E) by Ca{sup 2+}/calmodulin-dependent protein kinase I (CaMKI)

    Energy Technology Data Exchange (ETDEWEB)

    Onouchi, Takashi [Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795 (Japan); Sueyoshi, Noriyuki, E-mail: sueyoshi@ag.kagawa-u.ac.jp [Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795 (Japan); Ishida, Atsuhiko [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521 (Japan); Kameshita, Isamu [Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795 (Japan)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer CaMKP-N/PPM1E underwent proteolytic processing and translocated to cytosol. Black-Right-Pointing-Pointer The proteolysis was effectively inhibited by the proteasome inhibitors. Black-Right-Pointing-Pointer Ser-480 of zebrafish CaMKP-N was phosphorylated by cytosolic CaMKI. Black-Right-Pointing-Pointer Phosphorylation-mimic mutants of CaMKP-N showed enhanced activity. Black-Right-Pointing-Pointer These results suggest that CaMKP-N is regulated by CaMKI. -- Abstract: Nuclear Ca{sup 2+}/calmodulin-dependent protein kinase phosphatase (CaMKP-N/PPM1E) is an enzyme that dephosphorylates and downregulates multifunctional Ca{sup 2+}/calmodulin-dependent protein kinases (CaMKs) as well as AMP-dependent protein kinase. In our previous study, we found that zebrafish CaMKP-N (zCaMKP-N) underwent proteolytic processing and translocated to cytosol in a proteasome inhibitor-sensitive manner. In the present study, we found that zCaMKP-N is regulated by phosphorylation at Ser-480. When zCaMKP-N was incubated with the activated CaMKI, time-dependent phosphorylation of the enzyme was observed. This phosphorylation was significantly reduced when Ser-480 was replaced by Ala, suggesting that CaMKI phosphorylates Ser-480 of zCaMKP-N. Phosphorylation-mimic mutants, S480D and S480E, showed higher phosphatase activities than those of wild type and S480A mutant in solution-based phosphatase assay using various substrates. Furthermore, autophosphorylation of CaMKII after ionomycin treatment was more severely attenuated in Neuro2a cells when CaMKII was cotransfected with the phosphorylation-mimic mutant of zCaMKP-N than with the wild-type or non-phosphorylatable zCaMKP-N. These results strongly suggest that phosphorylation of zCaMKP-N at Ser-480 by CaMKI activates CaMKP-N catalytic activity and thereby downregulates multifunctional CaMKs in the cytosol.

  15. [On the effect of imipramine on blood composition, glucose level and alkaline phosphatase activity of leucocytes in non-emotive Wistar rats and animals of inbred TMB strain (author's transl)].

    Science.gov (United States)

    Freund, D; Freund, J L; Kahlau, F

    1981-01-01

    The acute effect of imipramine (Tofranil) on the composition of blood, blood sugar level and activity of alcaline phosphatase in leucocytes was studied in an experiment with 30 adult male TMB-rats. These findings were compared with those in non-emotive Wistar rats (the scores without stress and under the condition of psycho-pharmacological effects) as far as corresponding motor activity in both strains was concerned. Hematological findings in a non-stress condition are considered to be identical in both strains studied. Under the acute effect of imipramine only about 50% of the compared parameters are similar to each other. The differing course of the hematological reaction within the other 50% points to the presence of non-identical control mechanisms in both strains.

  16. Influencia de especies forestales sobre la actividad de las enzimas fosfatasa ácida y proteasas en un suelo de bosque Influence of tree species on the activity of acid phosphatase and protease in a forest soil

    Directory of Open Access Journals (Sweden)

    Rl Defrieri

    2008-12-01

    reflejaron mejor los cambios debidos a la influencia de las diferentes especies y de la época del año que otros parámetros químicos del suelo.Plant cover and especially the dominant tree species affect biological and chemical properties of the soil. Litter decomposition rate is affected by its N and P concentration. The aim of this work was to determine the different effects of forest tree species on some biochemical properties of the soil. The study site was located at the Reserva Natural Estricta Colonia Benítez, Chaco, Argentina. Soil samples were taken under trees of the four dominant species in the area and at two depths (0-10 cm and 10-20cm and moments: in summer and in winter. Activities of acid phosphatase and protease enzymes and some edaphic parameters were determined. The results obtained for all studied variables were significantly lower at the 10-20 cm depth, for all forest species and in both seasons. Values of enzyme activities showed significant differences between species only in surface samples where the incorporation of organic matter is greater and in summer. In these conditions, the values of enzymatic activities obtained in soils under each species ranged between 1,600 and 900 μg p-nitrophenol g-1 h-1 for acid phosphatase and between 850 y 450 g tyrosine g-1h-1 for protease. For two of the studied species, a relationship was found between the amount of litter produced, the different decomposition rates and the N and P concentrations in senescent leaves with the enzyme activities in soils. Inorganic N and available P concentrations in soils did not show significant differences between species. In this study, soil enzyme activities were more related to the overlying species than some measured soil parameters.

  17. Immobilization of alkaline phosphatase on magnetic particles by site-specific and covalent cross-linking catalyzed by microbial transglutaminase.

    Science.gov (United States)

    Moriyama, Kousuke; Sung, Kyunga; Goto, Masahiro; Kamiya, Noriho

    2011-06-01

    Bacterial alkaline phosphatase (BAP) was site-specifically and covalently immobilized on magnetic particles (MPs) using the enzymatic reaction of microbial transglutaminase (MTG). Immobilization efficiency was affected by the chemical surface treatment of MPs and immobilized BAP exhibited more than 90% of the initial activity after 10 rounds of recycling. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  19. Activation of Osteoblastic Function on Titanium Surface with Titanium-Doped Hydroxyapatite Nanoparticle Coating: An In Vitro Study.

    Science.gov (United States)

    Nakazawa, Masahiro; Yamada, Masahiro; Wakamura, Masato; Egusa, Hiroshi; Sakurai, Kaoru

    Titanium-doped hydroxyapatite (TiHA) nanoparticles contain titanium atoms in the hydroxyapatite lattice, which can physicochemically functionalize the titanium surface without modification of the surface topography. This study aimed to evaluate the physicochemical properties of machined or microroughened titanium surfaces coated with TiHA nanoparticles and the functions of osteoblasts cultured on them. Titanium disks with commercially available surface topography, such as machined or sandblasted, large-grit, and acid-etched (SLA) surfaces, were coated with TiHA. The disks with original or TiHA-coated surfaces were evaluated in topography, wettability, and chemical composition. Osteoblastic cells from rat femurs were cultured on the disks and evaluated in proliferation and differentiation. TiHA coating changed from hydrophobicity to hydrophilicity on both machined and SLA surfaces. Calcium and phosphate atoms were detected all over the surface with TiHA coating regardless of the surface topography. However, the considerable change in the inherent surface topographies was not observed on both types of surfaces after TiHA coating. Osteoblastic proliferative activity at day 4 was increased by TiHA coating on both types of surfaces. TiHA coating did not enhance expressions of bone matrix-related genes such as osteocalcin, osteopontin, bone sialoprotein, alkaline phosphatase, and collagen I. However, depositions of collagen, osteocalcin, and calcium in the culture at days 7 and 20 were increased on both types of surface topographies with TiHA coating. TiHA coating enhanced extracellular matrix formation on smooth and microroughened titanium surfaces by increasing osteoblastic proliferative activity without the deterioration of differentiation through hydrophilic and chemical functionalization.

  20. Persistently increased intestinal fraction of alkaline phosphatase

    DEFF Research Database (Denmark)

    Nathan, E; Baatrup, G; Berg, H

    1984-01-01

    Persistent elevation of the intestinal fraction of the alkaline phosphatase (API) as an isolated finding has to our knowledge not been reported previously. It was found in a boy followed during a period of 5.5 years. The only symptom was transient periodic fatigue observed at home, but not apparent...... during hospitalization. His blood type was O, RH+, Le (a-, b+) and he was a secretor of H-substance, which may be associated with rising API activity after fat-loading. In this case API was unchanged after fat-loading. Neither intestinal nor liver diseases were found, and no other cause for the elevated...

  1. The effect of phosphours and water deficit on phosphatase activity and proline accumulation in seedling cotyledons and roots of oilseed rape as compared to that of excised cotyledons and roots

    Directory of Open Access Journals (Sweden)

    Stanisław Flasiński

    2014-01-01

    Full Text Available Oilseed rape seedlings and excised cotyledons and roots were exposed to phosphorus and osmotic stress (-1 MPa: NaCl or PEG. The stress factors limited the growth of the seedlings and inhibited the growth of the excised roots and cotyledons. The phosphorus content in the cotyledons and roots depended on its level in the media and on the stress factors used. Phosphorus deficiency differentiated total phosphatase activity in seedling cotyledons and increased the activity in the excised cotyledons. In the excised and seedling roots, the lack of phosphorus, its deficiency and stress imposed by the addition of NaCl, caused an increase in total and specific phosphatase activity. Osmotic stress caused proline accumulation in both the seedling and excised cotyledons, but the effect of phosphorus stress was much smaller. Proline increase in seedling roots followed only after the osmotic stress caused by NaCl. The proline content in the excised roots was low. Stress factors lowered the protein content in the seedling and excised cotyledons. In both seedling and excised roots, the lowering of the protein content occurred mainly in response to osmotic stress. Kinetin modified metabolic responses in seedling cotyledons and roots. The use of in vitro culture allowed the elucidation of the tested responses. In excised cotyledons grown under stress conditions, kinetin increased the phosphorus and protein contents and lowered proline accumulation, suggesting that kinetin had the ability to overcome phosphorus and osmotic stress. The excised oilseed rape roots responded only slightly to kinetin (Drozdowska and Rogozińska 1984 and its effect was much smaller.

  2. Microbial activity in surface sediments of Chacopata-Bocaripo lagoon axis, Sucre State, Venezuela.

    Science.gov (United States)

    Segnini de B, Mary Isabel; Gómez, Irma; Brito, Leonor; Acosta, Vanessa; Troccoli, Luis

    2015-02-28

    The aim of this work was to evaluate the microbial activity of the surface sediments (0-10 cm) of the Chacopata-Bocaripo lagoon axis (Ch-BLA) through microbiological parameters: microbial biomass (Cmic) dehydrogenase activity (DHS), fluorescein diacetate hydrolysis (HFDA), arginine ammonification (AA) and biochemical parameters: phosphatase (PHa) and urease (URa) activity. They were determined during transition (July 2010) and upwelling (March 2011) periods. Total organic carbon (TOC) did not vary significantly (p⩾0.05) between climatic periods. All the parameters studied were higher in upwelling season: Cmic (191.79 mg Cmic kg(-1)), DHS (228.70 μg TFF g(-1) 24 h(-1)), HFDA (204.09 μg fluorescein g(-1) 24 h(-1)), AA (13.09 μg NH4-N g(-1) h(-1)), PHa (132.31 μg pNF g(-1) h(-1)), URa (12.90 μg NH4-N g(-1) h(-1)). They appear to be controlled by the availability and quality of nutrients in each climatic period, and were useful tools for evaluating changes in microbial activity in marine sediments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Plasma technology of the surface polymer activation

    International Nuclear Information System (INIS)

    Dutra, Jorge C.N.; Mello, Sandra C.; Massi, Marcos; Otani, Choyu; Maciel, Homero S.; Bittencourt, Edison

    2005-01-01

    A number of polymers, especially rubbers, require surface treatment to achieve a satisfactory level of adhesion. The surface of EPDM rubber vulcanized is high hydrophobicity and is not suited for a number of potential applications, in particular, for adhering to the polyurethane liner of solid rocket propellants. In this case, plasma treatment can be a very attractive process because it can efficiently increase the surface energy attributed to surface oxidation with the introduction of polar groups 1, 2. In order to investigate the influence of the parameters on the modifications of the treated surface samples of EPDM rubber by plasma generated by gas oxygen and argon, the water and methylene iodide contact angles were measured at room temperature with an image analyzing using the sessile drop technique 3 - 6 . (author)

  4. Acid phosphatase activity and leaf phosphorus content in soybean cultivars Atividade da fosfatase ácida e concentração foliar de fósforo em cultivares de soja

    Directory of Open Access Journals (Sweden)

    Roberto Wagner Cavalcanti Raposo

    2004-01-01

    Full Text Available The phosphate fertilization represents the most costly fraction of soybean crop production. Efficient soybean cultivars for P absorption and utilization in soils of medium available P are highly desirable and might contribute for increasing crop production potential. Thirty two soybean [Glycine max (L. Merr.] cultivars recommended for 'Cerrado' and differing in growth cycle (early, semi-early, semi-late, and late were grown in a dystrophic Typic Haplustox Cerrado soil to evaluate the acid phosphatase activity, P content in the diagnostic leaf, and shoot biomass. There were differences among the soybean cultivars within all maturation groups in acid phosphatase activity and shoot biomass. The diagnostic-leaf P-content showed significant differences on semi-late and late maturation groups' cultivars. The acid phosphatase activity correlated positively with the plant shoot biomass from semi-early (r = 0.46 and late (r = 0.47 cultivars, and negatively (r = -0.40 with the P content in the diagnostic leaf of late maturation cultivars. The occurrence of soybean cultivars with high and low acid phosphatase activity within the same maturation groups indicates the existence of different mechanisms involving P mobilization in the soil and internal plant P remobilization.A adubação fosfatada corresponde à fração mais onerosa do custo de produção da cultura da soja. A obtenção de cultivares de soja eficientes na absorção e utilização de fósforo (P em condição de média disponibilidade deste nutriente pode contribuir para aumentar o potencial produtivo da cultura. Trinta e dois cultivares de soja [Glycine max (L. Merr.], de ciclo precoce, semiprecoce, semitardio e tardio, recomendados para o cerrado, foram cultivados em Latossolo Vermelho-Amarelo distrófico típico, do cerrado, objetivando avaliar a atividade da fosfatase ácida, concentração de P na folha diagnóstico e biomassa da parte aérea. Ocorreram diferenças entre os cultivares

  5. Effect of growth conditions on expression of the acid phosphatase (cyx-appA) operon and the appY gene, which encodes a transcriptional activator of Escherichia coli

    DEFF Research Database (Denmark)

    Brøndsted, Lone; Atlung, Tove

    1996-01-01

    The expression and transcriptional regulation of the Escherichia coli cyx-appA operon and the appY gene has been investigated during different environmental conditions using single copy transcriptional lacZ fusions. The cyx-appA operon encodes acid phosphatase and a putative cytochrome oxidase.......ArcA and AppY activated transcription of the cyx-appA operon during entry into stationary phase and under anaerobic growth conditions. The expression of the cyx-appA operon was affected by the anaerobic energy metabolism.The presence of the electron acceptors nitrate and fumarate repressed the expression...... of the cyx-appA operon. The nitrate repression was partially dependent on NarL. A high expression of the operon was obtained in glucose medium supplemented with formate, where E.coli obtains energy by fermentation. The formate induction was independent of the fhlA gene product. The results presented...

  6. Kinetic studies of alkaline phosphatase extracted from rabbit ( Lepus ...

    African Journals Online (AJOL)

    Studies were carried out to ascertain some kinetic properties of alkaline phosphatase (ALP) extracted from Lepus townsendii liver. Incubation of ALP extract with 4-nitrophenylphosphate (4-NPP) formed the basis for determination of enzyme activity. Spectrophotometric method was used to assay the enzyme activity, and the ...

  7. c-Jun N-Terminal Kinase Inactivation by Mitogen-Activated Protein Kinase Phosphatase 1 Determines Resistance to Taxanes and Anthracyclines in Breast Cancer.

    Science.gov (United States)

    Rincón, Raúl; Zazo, Sandra; Chamizo, Cristina; Manso, Rebeca; González-Alonso, Paula; Martín-Aparicio, Ester; Cristóbal, Ion; Cañadas, Carmen; Perona, Rosario; Lluch, Ana; Eroles, Pilar; García-Foncillas, Jesús; Albanell, Joan; Rovira, Ana; Madoz-Gúrpide, Juan; Rojo, Federico

    2016-11-01

    MAPK phosphatase-1 (MKP-1) is overexpressed during malignant transformation of the breast in many patients, and it is usually associated with chemoresistance through interference with JNK-driven apoptotic pathways. Although the molecular settings of the mechanism have been documented, details about the contribution of MKP-1 to the failure of chemotherapeutic interventions are unclear. Transient overexpression of MKP-1 and treatment with JNK-modulating agents in breast carcinoma cells confirmed the mediation of MKP-1 in the resistance to taxanes and anthracyclines in breast cancer, through the inactivation of JNK1/2. We next assessed MKP-1 expression and JNK1/2 phosphorylation status in a large cohort of samples from 350 early breast cancer patients treated with adjuvant anthracycline-based chemotherapy. We detected that MKP-1 overexpression is a recurrent event predominantly linked to dephosphorylation of JNK1/2 with an adverse impact on relapse of the tumor and overall and disease-free survival. Moreover, MKP-1 and p-JNK1/2 determinations in 64 locally advanced breast cancer patients treated with neoadjuvant taxane-based chemotherapy showed an inverse correlation between MKP-1 overexpression (together with JNK1/2 inhibition) and the pathologic response of the tumors. Our results emphasize the importance of MKP-1 as a potential predictive biomarker for a subset of breast cancer patients with worse outcome and less susceptibility to treatment. Mol Cancer Ther; 15(11); 2780-90. ©2016 AACR. ©2016 American Association for Cancer Research.

  8. Analysis of serum corticosteroid-induced alkaline phosphatase isoenzyme in dogs with hepatobiliary diseases.

    Science.gov (United States)

    Kojima, K; Ohno, K; Kanemoto, H; Goto-Koshino, Y; Fukushima, K; Tsujimoto, H

    2017-05-01

    To reveal the relationship between canine corticosteroid-induced alkaline phosphatase isoenzyme activity and hepatobiliary diseases. Retrospective analysis of the relationship between serum corticosteroid-induced alkaline phosphatase activity and diagnosis, serum cortisol concentration and alanine transferase activity in dogs with hepatobiliary diseases. Dogs with a history of glucocorticoid administration were excluded. Seventy-two dogs with hepatobiliary diseases were analysed. The serum corticosteroid-induced alkaline phosphatase concentration was increased in dogs with hepatobiliary diseases. There was no correlation between serum cortisol concentration and serum corticosteroid-induced alkaline phosphatase percentage or activity. Dogs with hepatobiliary disease can exhibit high serum alkaline phosphatase activity even if the dogs have not been administrated glucocorticoids and the serum cortisol concentration is normal. © 2017 British Small Animal Veterinary Association.

  9. New Functions of the Inositol Polyphosphate 5-Phosphatases in Cancer.

    Science.gov (United States)

    Erneux, Christophe; Ghosh, Somadri; Ramos, Ana Raquel; Edimo, William's Elong

    2016-01-01

    Inositol polyphosphate 5-phosphatases act on inositol phosphates and phosphoinositides as substrates. They are 10 different isoenzymes and several splice variants in the human genome that are involved in a series of human pathologies such as the Lowe syndrome, the Joubert and MORM syndromes, breast cancer, glioblastoma, gastric cancer and several other type of cancers. Inositol 5-phosphatases can be amplified in human cancer cells, whereas the 3- and 4- phosphatase tumor suppressor PTEN and INPP4B, repectively are often repressed or deleted. The inositol 5-phosphatases are critically involved in a complex network of higly regulated phosphoinositides, affecting the lipid content of PI(3, 4, 5)P3, PI(4, 5)P2 and PI(3, 4)P2. This has an impact on the normal behavior of many intracellular target proteins e.g. protein kinase B (PKB/Akt) or actin binding proteins and final biological responses. The production of PI(3, 4P)2 by dephosphorylation of the substrate PI(3, 4, 5)P3 is particularly important as it produces a new signal messenger in the control of cell migration, invasion and endocytosis. New inhibitors/activators of inositol 5- phosphatases have recently been identified for the possible control of their activity in several human pathologies such as inflamation and cancer.

  10. Surface composition of carburized tungsten trioxide and its catalytic activity

    International Nuclear Information System (INIS)

    Nakazawa, M.; Okamoto, H.

    1985-01-01

    The surface composition and electronic structure of carburized tungsten trioxide are investigated using x-ray photoelectron spectroscopy (XPS). The relationship between the surface composition and the catalytic activity for methanol electro-oxidation is clarified. The tungsten carbide concentration in the surface layer increases with the carburization time. The formation of tungsten carbide enhances the catalytic activity. On the other hand, the presence of free carbon or tungsten trioxide in the surface layer reduces the activity remarkably. It is also shown that, the higher the electronic density of states near the Fermi level, the higher the catalytic activity

  11. Controlling PTEN (Phosphatase and Tensin Homolog) Stability

    Science.gov (United States)

    Gupta, Amit

    2016-01-01

    Phosphatase and tensin homolog (PTEN) is a phosphoinositide lipid phosphatase and one of the most frequently disrupted tumor suppressors in many forms of cancer, with even small reductions in the expression levels of PTEN promoting cancer development. Although the post-translational ubiquitination of PTEN can control its stability, activity, and localization, a detailed understanding of how PTEN ubiquitination integrates with other cellular regulatory processes and may be dysregulated in cancer has been hampered by a poor understanding of the significance of ubiquitination at individual sites. Here we show that Lys66 is not required for cellular activity, yet dominates over other PTEN ubiquitination sites in the regulation of protein stability. Notably, combined mutation of other sites (Lys13, Lys80, and Lys289) has relatively little effect on protein expression, protein stability, or PTEN polyubiquitination. The present work identifies a key role for Lys66 in the regulation of PTEN expression and provides both an opportunity to improve the stability of PTEN as a protein therapy and a mechanistic basis for efforts to stabilize endogenous PTEN. PMID:27405757

  12. Presence of multiple acid phosphatases activity in seedlings of cucumber, radish and rocket salad Presença de atividade de múltiplas fosfatases ácidas em plântulas de pepino, rabanete e rúcula

    Directory of Open Access Journals (Sweden)

    Luciane Almeri Tabaldi

    2008-06-01

    Full Text Available Acid phosphatases (3.1.3.2 are a group of enzymes widely distributed in nature, which catalyze the hydrolysis of a variety of phosphate esters in the pH range of 4-6. We confirmed the presence of acid phosphatases in seedlings of cucumber (Cucumis sativus, radish (Raphanus sativus and rocket salad (Eruca vesicaria under different assay conditions using a rapid and simple preparation. The results showed that the optimum pH and temperature used for all species were close to 5.5 and 35°C, respectively. The enzyme was inhibited by molybdate, fluoride, azide, levamisole, orthovanadate, Zn2+ and Cu2+. Suramin had no effect on enzyme activity. The acid phosphatase from cucumber, radish and rocket salad hydrolyzed a wide variety of phosphate esters and the highest activity was observed with PPi, ATP and GTP. These results demonstrate that the enzyme investigated in this study is different from well known ester phosphate cleaving plant enzymes (apyrase and inorganic pyrophosphatases and this preparation could be a useful tool to future toxicological studies and to study initially all isoforms of acid phosphatase.As fosfatases ácidas (3.1.3.2 são um grupo de enzimas amplamente distribuídas na natureza, as quais catalisam a hidrólise de uma variedade de ésteres de fosfato com uma variação de pH entre quatro e seis. Foi confirmada a presença de fosfatases ácidas em plântulas de pepino (Cucumis sativus, rabanete (Raphanus sativus e rúcula (Eruca vesicaria sob diferentes condições de ensaio usando uma preparação rápida e simples. Os resultados mostraram que o pH e a temperatura ótimos para todas as espécies foram 5,5 e 35°C, respectivamente. A enzima foi inibida por molibdato, fluoreto, azida, levamisole, ortovanadato, Zn2+ e Cu2+. O inibidor suramim não afetou a atividade enzimática. As fosfatases ácidas de pepino, rabanete e rúcula hidrolisaram uma ampla variedade de ésteres de fosfato e a maior atividade foi observada com PPi, ATP

  13. Surface activity of thymol: implications for an eventual pharmacological activity.

    Science.gov (United States)

    Sánchez, Mariela E; Turina, Anahí del V; García, Daniel A; Nolan, M Verónica; Perillo, María A

    2004-03-15

    In the present work, we studied the ability of thymol to affect the organization of model membranes and the activity of an intrinsic membrane protein, the GABA(A) receptor (GABA(A)-R). In this last aspect, we tried to elucidate if the action mechanism of this terpene at the molecular level, involves its binding to the receptor protein, changes in the organization of the receptor molecular environment, or both. The self-aggregation of thymol in water with a critical micellar concentration approximately = 4 microM and its ability to penetrate in monomolecular layers of soybean phosphatidylcholine (sPC) at the air-water interface, even at surface pressures above the equilibrium, lateral pressure of natural bilayers were demonstrated. Thymol affected the self-aggregation of Triton X-100 and the topology of sPC vesicles. It also increased the polarity of the membrane environment sensed by the electrochromic dye merocyanine. A dipolar moment of 1.341 Debye was calculated from its energy-minimized structure. Its effect on the binding of [3H]-flunitrazepam ([3H]-FNZ) to chick brain synaptosomal membranes changed qualitatively from a tendency to the inhibition to a clear activatory regime, up on changing the phase state of the terpene (from a monomeric to a self-aggregated state). Above its CMC, thymol increased the affinity of the binding of [3H]-FNZ (K(d-control)= 2.9, K(d-thymol)= 1.7 nM) without changing the receptor density (B(max-control)= 910, B(max-thymol)= 895 fmol/mg protein). The activatory effect of thymol on the binding of [ [3H]-FNZ was observed even in the presence of the allosteric activator gamma-aminobutyric acid (GABA) at a concentration of maximal activity, and was blocked by the GABA antagonist bicuculline. Changes in the dipolar arrangement and in the molecular packing of GABA(A)-R environment are discussed as possible mediators of the action mechanism of thymol.

  14. Alkaline Phosphatase, Soluble Extracellular Adenine Nucleotides, and Adenosine Production after Infant Cardiopulmonary Bypass.

    Science.gov (United States)

    Davidson, Jesse A; Urban, Tracy; Tong, Suhong; Twite, Mark; Woodruff, Alan; Wischmeyer, Paul E; Klawitter, Jelena

    2016-01-01

    Decreased alkaline phosphatase activity after infant cardiac surgery is associated with increased post-operative cardiovascular support requirements. In adults undergoing coronary artery bypass grafting, alkaline phosphatase infusion may reduce inflammation. Mechanisms underlying these effects have not been explored but may include decreased conversion of extracellular adenine nucleotides to adenosine. 1) Evaluate the association between alkaline phosphatase activity and serum conversion of adenosine monophosphate to adenosine after infant cardiac surgery; 2) assess if inhibition/supplementation of serum alkaline phosphatase modulates this conversion. Pre/post-bypass serum samples were obtained from 75 infants alkaline phosphatase and CD73. Low and high concentration 13C5-adenosine monophosphate (simulating normal/stress concentrations) were used. Effects of alkaline phosphatase supplementation on adenosine monophosphate clearance were also assessed. Changes in serum alkaline phosphatase activity were strongly correlated with changes in 13C5-adenosine production with or without CD73 inhibition (r = 0.83; palkaline phosphatase activity (≤80 U/L) generated significantly less 13C5-adenosine, particularly in the presence of high concentration 13C5-adenosine monophosphate (10.4μmol/L vs 12.9μmol/L; p = 0.0004). Inhibition of alkaline phosphatase led to a marked decrease in 13C5-adenosine production (11.9μmol/L vs 2.7μmol/L; palkaline phosphatase or high dose bovine intestinal alkaline phosphatase doubled 13C5-adenosine monophosphate conversion to 13C5-adenosine (pAlkaline phosphatase represents the primary serum ectonucleotidase after infant cardiac surgery and low post-operative alkaline phosphatase activity leads to impaired capacity to clear adenosine monophosphate. AP supplementation improves serum clearance of adenosine monophosphate to adenosine. These findings represent a potential therapeutic mechanism for alkaline phosphatase infusion during cardiac

  15. Molecular enzymology underlying regulation of protein phosphatase-1 by natural toxins.

    Science.gov (United States)

    Holmes, C F B; Maynes, J T; Perreault, K R; Dawson, J F; James, M N G

    2002-11-01

    The protein serine/threonine phosphatases constitute a unique class of enzymes that are critical for cell regulation, as they must counteract the activities of thousands of protein kinases in human cells. Uncontrolled inhibition of phosphatase activity by toxic inhibitors can lead to widespread catastrophic effects. Over the past decade, a number of natural product toxins have been identified that specifically and potently inhibit protein phosphatase-1 and 2A. Amongst these are the cyanobacteria-derived cyclic heptapeptide microcystin-LR and the polyether fatty acid okadaic acid from dinoflagellate sources. The molecular mechanism underlying potent inhibition of protein phosphatase-1 by these toxins is becoming clear through insights gathered from diverse sources. These include: 1. Comparison of structure-activity relationships amongst the different classes of toxins. 2. Delineation of the structural differences between protein phosphatase-1 and 2A that account for their differing sensitivity to toxins, particularly okadaic acid and microcystin-LR. 3. Determination of the crystal structure of protein phosphatase-1 with microcystin-LR, okadaic acid and calyculin bound. 4. Site-specific mutagenesis and biochemical analysis of protein phosphatase-1 mutants. Taken together, these data point to a common binding site on protein phosphatase-1 for okadaic acid, microcystin-LR and the calyculins. However, careful analysis of these data suggest that each toxin binds to the common binding site in a subtly different way, relying on distinct structural interactions such as hydrophobic binding, hydrogen bonding and electrostatic interactions to different degrees. The insights derived from studying the molecular enzymology of protein phosphatase-1 may help explain the different sensitivities of other structurally conserved protein serine/theonine phosphatases to toxin inhibition. Furthermore, studies on the binding of structurally diverse toxins at the active site of protein

  16. Elevated serum level of human alkaline phosphatase in obesity.

    Science.gov (United States)

    Khan, Abdul Rehman; Awan, Fazli Rabbi; Najam, Syeda Sadia; Islam, Mehboob; Siddique, Tehmina; Zain, Maryam

    2015-11-01

    To investigate a correlation between serum alkaline phosphatase level and body mass index in human subjects. The comparative cross-sectional study was carried out at the National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan, from April 2012 to June 2013. Blood serum alkaline phosphatase levels were estimated and the subjects were divided into three sub-groups on the basis of their body mass. normal weight (27kg/m2) subjects. The serum samples were used for the estimation of clinically important biochemical parameters, using commercial kits on clinical chemistry analyser. Of the 197 subjects, 97(49%) were obese and 100(51%) were non-obese. The serum alkaline phosphatase level increased in obese (214±6.4 IU/L) compared to the non-obese subjects (184.5±5 IU/L). Furthermore, a significant linear relationship (r=0.3;p-0.0001) was found between serum alkaline phosphatase and body mass index. Other biochemical variables were not correlated to the body mass index. Over activity and higher amounts of alkaline phosphatase were linked to the development of obesity.

  17. Elevated Serum Level of Human Alkaline Phosphatase in Obesity

    International Nuclear Information System (INIS)

    Khan, A. R.; Awan, F. R.; Najam, S. S.; Islam, M.; Siddique, T.; Zain, M.

    2015-01-01

    Objective: To investigate a correlation between serum alkaline phosphatase level and body mass index in human subjects. Methods: The comparative cross-sectional study was carried out at the National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan, from April 2012 to June 2013. Blood serum alkaline phosphatase levels were estimated and the subjects were divided into three sub-groups on the basis of their body mass index: normal weight (<25kg/m2), overweight (25-27kg/m2) and obese (>27kg/m2) subjects. The serum samples were used for the estimation of clinically important biochemical parameters, using commercial kits on clinical chemistry analyser. Results: Of the 197 subjects, 97(49 percent) were obese and 100(51 percent) were non-obese. The serum alkaline phosphatase level increased in obese (214±6.4 IU/L) compared to the non-obese subjects (184.5±5 IU/L). Furthermore, a significant linear relationship (r=0.3;p-0.0001) was found between serum alkaline phosphatase and body mass index. Other biochemical variables were not correlated to the body mass index. Conclusion: Over activity and higher amounts of alkaline phosphatase were linked to the development of obesity. (author)

  18. Sperm cell surface dynamics during activation and fertilization

    NARCIS (Netherlands)

    Boerke, A.|info:eu-repo/dai/nl/304822922

    2013-01-01

    Before the sperm cell can reach the oocyte it needs to be activated and to undergo a series of preparative steps. The sperm surface dynamics was studied in relation to this activation process and the modifications and removal of sperm surface components havebeen investigated. Bicarbonate-induced

  19. Temperature effects on surface activity and application in oxidation ...

    Indian Academy of Sciences (India)

    Keywords. Surface activity; cetyl trimethylammonium bromide; sodium dodecyl sulfate; temperature; oxidation. ... Catalytic effect on oxidation of toluene derivatives with potassium permanganate follows the order CTAB-SDS > SDS > CTAB. This is not caused by the dissociative effect of CTAB-SDS with low surface activity at ...

  20. Control of placental alkaline phosphatase gene expression in HeLa cells: induction of synthesis by prednisolone and sodium butyrate

    International Nuclear Information System (INIS)

    Chou, J.Y.; Takahashi, S.

    1987-01-01

    HeLa S 3 cells produce an alkaline phosphatase indistinguishable from the enzyme from human term placenta. The phosphatase activity in these cells was induced by both prednisolone and sodium butyrate. Both agents stimulated de novo synthesis of the enzyme. The increase in phosphatase activity paralleled the increase in immunoactivity and biosynthesis of placental alkaline phosphatase. The fully processed phosphatase monomer in control, prednisolone-treated or butyrate-treated cells was a 64.5 K polypeptide, measured by both incorporation of L-[ 35 S]methionine into enzyme protein and active-site labeling. The 64.5K polypeptide was formed by the incorporation of additional N-acetylneuraminic acid moieties to a precursor polypeptide of 61.5K. However, this biosynthetic pathway was identified only in butyrate-treated cells. In prednisolone-treated cells, the processing of 61.5K to 64.5K monomer was accelerated, and the presence of the 61.5 precursor could only be detected by either neuraminidase or monensin treatment. Phosphatase mRNA which comigrated with the term placental alkaline phosphatase mRNA of 2.7 kilobases was induced in the presence of either prednisolone or butyrate. Alkaline phosphatase mRNA is untreated HeLa S 3 cells migrated slightly faster than the term placental alkaline phosphatase mRNA. Butyrate also induced a second still faster migrating alkaline phosphatase mRNA. Both prednisolone and butyrate increased the steady-state levels of placental alkaline phosphatase mRNA. The data indicate that the increase in phosphatase mRNA by prednisolone and butyrate resulted in the induction of alkaline phosphatase activity and biosynthesis in HeLa S 3 cells. Furthermore, both agents induced the expression of different alkaline phosphatase gene transcripts without altering its protein product

  1. Coordinated surface activities in Variovorax paradoxus EPS

    Directory of Open Access Journals (Sweden)

    Gregory Glenn A

    2009-06-01

    Full Text Available Abstract Background Variovorax paradoxus is an aerobic soil bacterium frequently associated with important biodegradative processes in nature. Our group has cultivated a mucoid strain of Variovorax paradoxus for study as a model of bacterial development and response to environmental conditions. Colonies of this organism vary widely in appearance depending on agar plate type. Results Surface motility was observed on minimal defined agar plates with 0.5% agarose, similar in nature to swarming motility identified in Pseudomonas aeruginosa PAO1. We examined this motility under several culture conditions, including inhibition of flagellar motility using Congo Red. We demonstrated that the presence of a wetting agent, mineral, and nutrient content of the media altered the swarming phenotype. We also demonstrated that the wetting agent reduces the surface tension of the agar. We were able to directly observe the presence of the wetting agent in the presence and absence of Congo Red, and found that incubation in a humidified chamber inhibited the production of wetting agent, and also slowed the progression of the swarming colony. We observed that swarming was related to both carbon and nitrogen sources, as well as mineral salts base. The phosphate concentration of the mineral base was critical for growth and swarming on glucose, but not succinate. Swarming on other carbon sources was generally only observed using M9 salts mineral base. Rapid swarming was observed on malic acid, d-sorbitol, casamino acids, and succinate. Swarming at a lower but still detectable rate was observed on glucose and sucrose, with weak swarming on maltose. Nitrogen source tests using succinate as carbon source demonstrated two distinct forms of swarming, with very different macroscopic swarm characteristics. Rapid swarming was observed when ammonium ion was provided as nitrogen source, as well as when histidine, tryptophan, or glycine was provided. Slower swarming was observed

  2. B56δ-related protein phosphatase 2A dysfunction identified in patients with intellectual disability

    NARCIS (Netherlands)

    Houge, Gunnar; Haesen, Dorien; Vissers, Lisenka E L M; Mehta, Sarju; Parker, Michael J.; Wright, Michael; Vogt, Julie; McKee, Shane; Tolmie, John L.; Cordeiro, Nuno; Kleefstra, Tjitske; Willemsen, Marjolein H.; Reijnders, Margot R F; Berland, Siren; Hayman, Eli; Lahat, Eli; Brilstra, Eva H.; Van Gassen, Koen L I; Zonneveld-Huijssoon, Evelien; De Bie, Charlotte I.; Hoischen, Alexander; Eichler, Evan E.; Holdhus, Rita; Steen, Vidar M.; Døskeland, Stein Ove; Hurles, Matthew E.; FitzPatrick, David R.; Janssens, Veerle

    2015-01-01

    Here we report inherited dysregulation of protein phosphatase activity as a cause of intellectual disability (ID). De novo missense mutations in 2 subunits of serine/threonine (Ser/Thr) protein phosphatase 2A (PP2A) were identified in 16 individuals with mild to severe ID, long-lasting hypotonia,

  3. B56delta-related protein phosphatase 2A dysfunction identified in patients with intellectual disability

    NARCIS (Netherlands)

    Houge, G.; Haesen, D.; Vissers, L.E.L.M.; Mehta, S.; Parker, M.J.; Wright, M.; Vogt, J.; McKee, S.; Tolmie, J.L.; Cordeiro, N.; Kleefstra, T.; Willemsen, M.H.; Reijnders, M.R.F.; Berland, S.; Hayman, E.; Lahat, E.; Brilstra, E.H.; Gassen, K.L. van; Zonneveld-Huijssoon, E.; Bie, C.I. De; Hoischen, A.; Eichler, E.E.; Holdhus, R.; Steen, V.M.; Doskeland, S.O.; Hurles, M.E.; FitzPatrick, D.R.; Janssens, V.

    2015-01-01

    Here we report inherited dysregulation of protein phosphatase activity as a cause of intellectual disability (ID). De novo missense mutations in 2 subunits of serine/threonine (Ser/Thr) protein phosphatase 2A (PP2A) were identified in 16 individuals with mild to severe ID, long-lasting hypotonia,

  4. Biocatalysis with Sol-Gel Encapsulated Acid Phosphatase

    Science.gov (United States)

    Kulkarni, Suhasini; Tran, Vu; Ho, Maggie K.-M.; Phan, Chieu; Chin, Elizabeth; Wemmer, Zeke; Sommerhalter, Monika

    2010-01-01

    This experiment was performed in an upper-level undergraduate biochemistry laboratory course. Students learned how to immobilize an enzyme in a sol-gel matrix and how to perform and evaluate enzyme-activity measurements. The enzyme acid phosphatase (APase) from wheat germ was encapsulated in sol-gel beads that were prepared from the precursor…

  5. Kinetic Studies of Alkaline Phosphatase from the Liver of Agama ...

    African Journals Online (AJOL)

    Kinetic studies were carried out on alkaline phosphatase (ALP) extracted from the liver of Agama agama lizard. Incubation of ALP extract with para – nitrophenyl phosphate formed the basis for the determination of enzyme activity. Spectrophotometric method was used to assay the enzyme, and the kinetic constants: ...

  6. Active Surface Compensation for Large Radio Telescope Antennas

    Science.gov (United States)

    Wang, Congsi; Li, Haihua; Ying, Kang; Xu, Qian; Wang, Na; Duan, Baoyan; Gao, Wei; Xiao, Lan; Duan, Yuhu

    2018-03-01

    With the development of radio telescope antennas with large apertures, high gain, and wide frequency bands, compensation methods, such as mechanical or electronic compensation, are obviously essential to ensure the electrical performance of antennas that work in complex environments. Since traditional compensation methods can only adjust antenna pointing but not the surface accuracy, which are limited for obtaining high surface precision and aperture efficiency, active surface adjustment has become an indispensable tool in this field. Therefore, the development process of electrical performance compensation methods for radio telescope antennas is introduced. Further, a series of analyses of the five key technologies of active surface adjustment is presented. Then, four typical large antennas that have been designed with active main reflector technology are presented and compared. Finally, future research directions and suggestions for reflector antenna compensation method! s based on active surface adjustment are presented.

  7. Surface enhanced Raman optical activity (SEROA)

    DEFF Research Database (Denmark)

    Abdali, Salim; Blanch, E.W.

    2008-01-01

    Raman optical activity (ROA) directly monitors the stereochemistry of chiral molecules and is now an incisive probe of biomolecular structure. ROA spectra contain a wealth of information on tertiary folding, secondary structure and even the orientation of individual residues in proteins and nucleic...

  8. From phosphatases to vanadium peroxidases: A similar architecture of the active site

    Science.gov (United States)

    Hemrika, Wieger; Renirie, Rokus; Dekker, Henk L.; Barnett, Phil; Wever, Ron

    1997-01-01

    We show here that the amino acid residues contributing to the active sites of the vanadate containing haloperoxidases are conserved within three families of acid phosphatases; this suggests that the active sites of these enzymes are very similar. This is confirmed by activity measurements showing that apochloroperoxidase exhibits phosphatase activity. These observations not only reveal interesting evolutionary relationships between these groups of enzymes but may also have important implications for the research on acid phosphatases, especially glucose-6-phosphatase—the enzyme affected in von Gierke disease—of which the predicted membrane topology may have to be reconsidered. PMID:9122162

  9. Histochemistry of placental alkaline phosphatase in preeclampsia

    OpenAIRE

    Shevade, Sapna Prashant; Arole, Vasanti; Paranjape, Vaishali Mohan; Bharambe, Vaishaly Kishore

    2016-01-01

    Objectives: Placental alkaline phosphatase (PALP) is synthesized in placenta and increases with gestational age. Alkaline phosphatase supports pregnancy and could play an essential role in nutrient supply and growth of the fetus. Preeclampsia is a systemic disorder which affects 5 to 7 percent of women worldwide and is a major cause for maternal and neonatal morbidity and mortality. As it has a major role in fetal growth, nutrition and defense mechanism study of alkaline phosphatase enzymatic...

  10. Acid-base characteristics of powdered-activated-carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Reed, B.E. (West Virginia Univ., Morgantown (United States)); Jensen, J.N.; Matsumoto, M.R. (State Univ. of New York, Buffalo (United States))

    Adsorption of heavy metals onto activated carbon has been described using the surface-complex-formation (SCF) model, a chemical equilibrium model. The SCF model requires a knowledge of the amphoteric nature of activated carbon prior to metal adsorption modeling. In the past, a single-diprotic-acid-site model had been employed to describe the amphoteric nature of activated-carbon surfaces. During this study, the amphoteric nature of two powdered activated carbons were investigated, and a three-monoprotic site surface model was found to be a plausible alternative. The single-diprotic-acid-site and two-monoprotic-site models did not describe the acid-base behavior of the two carbons studied adequately. The two-diprotic site was acceptable for only one of the study carbons. The acid-base behavior of activated carbon surfaces seem to be best modeled as a series of weak monoprotic acids.

  11. Aspirin inhibits lipopolysaccharide-induced COX-2 expression and PGE2 production in porcine alveolar macrophages by modulating protein kinase C and protein tyrosine phosphatase activity

    OpenAIRE

    Duan, Yuzhong; Chen, Fanglin; Zhang, Anmei; Zhu, Bo; Sun, Jianguo; Xie, Qichao; Chen, Zhengtang

    2014-01-01

    Aspirin has been demonstrated to be effective in inhibiting COX-2 and PGE2 in Alveolar macrophages (AMs). However, the mechanisms have not been fully understood. In the present study, we found that pretreatment with aspirin inhibited LPS-induced COX-2 and PGE2 upregulation, IκBα degradation, NFκB activation and the increase of PKC activity, but elevated LPS-induced the decrease of PTP activity. The PKC inhibitor calphostin C dramatically reduced the COX-2 mRNA and PGE2 levels, but the PTP inh...

  12. Stimulation of Suicidal Erythrocyte Death by Phosphatase Inhibitor Calyculin A

    Directory of Open Access Journals (Sweden)

    Mustafa Almasry

    2016-11-01

    Full Text Available Background/Aims: The serine/threonine protein phosphatase 1 and 2a inhibitor Calyculin A may trigger suicidal death or apoptosis of tumor cells. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+] i. Eryptosis is fostered by activation of staurosporine sensitive protein kinase C, SB203580 sensitive p38 kinase, and D4476 sensitive casein kinase. Eryptosis may further involve zVAD sensitive caspases. The present study explored, whether Calyculin A induces eryptosis and, if so, whether its effect requires Ca2+ entry, kinases and/or caspases Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, and [Ca2+] i from Fluo-3 fluorescence, as determined by flow cytometry. Results: A 48 hours exposure of human erythrocytes to Calyculin A (≥ 2.5 nM significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter and significantly increased Fluo-3 fluorescence. The effect of Calyculin A on annexin-V-binding was significantly blunted by removal of extracellular Ca2+, by staurosorine (1 µM, SB203580 (2 µM, D4476 (10 µM, and zVAD (10 µM. Conclusions: Calyculin A triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part requiring Ca2+ entry, kinase activity and caspase activation.

  13. Surface coverage dictates the surface bio-activity of D-amino acid oxidase.

    Science.gov (United States)

    Herrera, Elisa; Giacomelli, Carla E

    2014-05-01

    This work presents a systematic study on the relationship between the adsorption mechanism and the surface bio-activity of D-amino acid oxidase (pkDAAO). This rational approach is based on measuring the characteristic filling and relaxation times under different experimental conditions. With such a goal, real-time adsorption-desorption experiments at different degrees of surface coverage were performed tuning the electrostatic and hydrophobic interactions by changing the pH condition for the adsorption and the substrate properties (silica or gold). Surface bio-activity was measured in situ by amperometry using the bio-functional surface as the working electrode and ex situ by spectrophotometry. On both solid substrates, pkDAAO adsorption is a transport-controlled process, even under unfavorable electrostatic interactions (charged protein and substrate with the same sign) due to the high percentage of basic amino acids in the enzyme. On silica, the relaxation step is electrostatic in nature and occurs in the same time-scale as filling the surface when the substrate and the enzyme are oppositely charged at low surface coverage. Under unfavorable electrostatic conditions, the relaxation (if any) occurs at long time. Accordingly, the bio-activity of the native pkDAAO is preserved at any surface coverage. On gold, this step is driven by hydrophobic interactions (pH-independent) and the surface bio-activity is highly dependent on the degree of surface coverage. Under these conditions, the surface bio-activity is preserved only at high surfaces coverage. Our results clearly indicate that pkDAAO bio-functionalized surfaces cannot be coupled to amperometry because the analyte interferes the electrochemical signal. However, this simple bio-functionalized strategy can be joined to other detection methods. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Fibroblast adhesion and activation onto micro-machined titanium surfaces.

    Science.gov (United States)

    Guillem-Marti, J; Delgado, L; Godoy-Gallardo, M; Pegueroles, M; Herrero, M; Gil, F J

    2013-07-01

    Surface modifications performed at the neck of dental implants, in the manner of micro-grooved surfaces, can reduce fibrous tissue encapsulation and prevent bacterial colonization, thereby improving fibrointegration and the formation of a biological seal. However, the applied procedures are technically complex and/or time consuming methods. The aim of this study was to analyse the fibroblast behaviour on modified titanium surfaces obtained, applying a simple and low-cost method. An array of titanium surfaces was obtained using a commercial computerized numerical control lathe, modifying the feed rate and the cutting depth. To elucidate the potential ability of the generated surfaces to activate connective tissue cells, a thorough gene (by real time - qPCR) and protein (by western blot or zymography) expression and cellular response characterization (cell morphology, cell adhesion and cell activation by secreting extracellular matrix (ECM) components and their enzyme regulators) was performed. Micro-grooved surfaces have statistically significant differences in the groove's width (approximately 10, 50 and 100 μm) depending on the applied advancing fixed speed. Field emission scanning electron microscopy images showed that fibroblasts oriented along the generated grooves, but they were only entirely accommodated on the wider grooves (≥50 μm). Micro-grooved surfaces exhibited an earlier cell attachment and activation, as seen by collagen Iα1 and fibronectin deposition and activation of ECM remodelling enzymes, compared with the other surfaces. However, fibroblasts could remain in an activated state on narrower surfaces (micro-grooved surfaces could improve implant integration at the gingival site with respect to polished surfaces. Micro-grooved surfaces enhance early fibroblast adhesion and activation, which could be critical for the formation of a biological seal and finally promote tissue integration. Surfaces with wider grooves (≥50 μm) seem to be more

  15. Surface activity of Acinetobacter calcoaceticus sp. 2CA2

    Energy Technology Data Exchange (ETDEWEB)

    Neufeld, R.J.; Zajic, J.E.

    1984-01-01

    The hydrocarbon metabolizing Acinetobacter calcoaceticus sp. 2CA2 reduces the surface tension of the culture broth during growth on liquid hydrocarbons. This activity, which is not evident during growth on soluble substrates, is associated with the whole cells. Removing the cells from the culture broth increases the surface tension of the liquid phase. The cells when resuspended in water result in a dramatic lowering of the surface tension. Acinetobacter sp. 2CA2 tends to partition between the two liquid phases during growth on hydrocarbons. Both the hydrocarbon bound and nonadhering cells are equally surface active. The whole cells are also able to form and stabilize kerosene-water emulsions. This ability is not related to the lowering of the liquid surface or interfacial tension, since both surface active and nonsurface active cells demonstrated the same emulsifying properties. An extracellular lipopeptide produced during growth on hydrocarbons is not surface active but effectively forms and stabilizes kerosene-water emulsions. The cells and extracellular lipopeptide are also effective in de-emulsifying surfactant stabilized test emulsions. The cells and extracellular lipopeptide are also effective in de-emulsifying surfactant stabilized test emulsions. The lipopeptide product reduced the half-life of a Tween-Span (TS) stabilized kerosene-water emulsion from 650 to 0.4 h at product concentrations of less than 1% (w/v).

  16. The muscle-specific protein phosphatase PP1G/R(GL)(G(M))is essential for activation of glycogen synthase by exercise

    DEFF Research Database (Denmark)

    Aschenbach, W G; Suzuki, Y; Breeden, K

    2001-01-01

    that was originally postulated to mediate insulin control of glycogen metabolism. However, we recently showed (Suzuki, Y., Lanner, C., Kim, J.-H., Vilardo, P. G., Zhang, H., Jie Yang, J., Cooper, L. D., Steele, M., Kennedy, A., Bock, C., Scrimgeour, A., Lawrence, J. C. Jr., L., and DePaoli-Roach, A. A. (2001) Mol....... Cell. Biol. 21, 2683-2694) that insulin activates GS in muscle of R(GL)(G(M)) knockout (KO) mice similarly to the wild type (WT). To determine whether PP1G is involved in glycogen metabolism during muscle contractions, R(GL) KO and overexpressors (OE) were subjected to two models of contraction...... basal glycogen levels, exhibited impaired maximal exercise capacity, but contraction-induced activation of glucose transport was unaffected. The R(GL) OE mice are characterized by enhanced GS activity ratio and an approximately 3-4-fold increase in glycogen content in skeletal muscle. These animals were...

  17. A macro-enzyme cause of an isolated increase of alkaline phosphatase.

    Science.gov (United States)

    Cervinski, Mark A; Lee, Hong Kee; Martin, Isabella W; Gavrilov, Dimitar K

    2015-02-02

    Macroenzyme complexes of serum enzymes and antibody can increase the circulating enzymatic activity and may lead to unnecessary additional testing and procedures. Laboratory physicians and scientists need to be aware of techniques to identify macroenzyme complexes when suspected. To investigate the possibility of a macro-alkaline phosphatase in the serum of a 74 year old male with persistently increased alkaline phosphatase we coupled a protein A/G agarose affinity chromatography technique with isoenzyme electrophoresis to look for the presence of macro-alkaline phosphatase. The majority of the alkaline phosphatase activity in the patient's serum sample was bound to the column and only a minor fraction (25%) of alkaline phosphatase activity was present in the column flow-through. The alkaline phosphatase activity was also found to co-elute with the immunoglobulins in the patient sample. The alkaline phosphatase activity in a control serum sample concurrently treated in the same manner did not bind to the column and was found in the column flow-through. The use of protein A/G agarose affinity chromatography is a rapid and simple method that can be applied to the investigation of other macro-enzyme complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Aspirin inhibits lipopolysaccharide-induced COX-2 expression and PGE2 production in porcine alveolar macrophages by modulating protein kinase C and protein tyrosine phosphatase activity.

    Science.gov (United States)

    Duan, Yuzhong; Chen, Fanglin; Zhang, Anmei; Zhu, Bo; Sun, Jianguo; Xie, Qichao; Chen, Zhengtang

    2014-01-01

    Aspirin has been demonstrated to be effective in inhibiting COX-2 and PGE(2) in Alveolar macrophages (AMs). However, the mechanisms have not been fully understood. In the present study, we found that pretreatment with aspirin inhibited LPS-induced COX-2 and PGE(2) upregulation, IκBα degradation, NFκB activation and the increase of PKC activity, but elevated LPS-induced the decrease of PTP activity. The PKC inhibitor calphostin C dramatically reduced the COX-2 mRNA and PGE(2) levels, but the PTP inhibitor peroxovanadium (POV) significantly increased the COX-2 mRNA and PGE(2) levels. Furthermore, the PTP inhibitor mitigated the inhibitory effect of aspirin on COX-2 and PGE(2) upregulation and NF-κB activation, whereas the PKC inhibitor enhanced the inhibitory effects of aspirin on the production of COX-2 and PGE(2). Our data indicate a novel mechanism by which aspirin acts as a potent anti-inflammatory agent in alveolus macrophages and ALI.

  19. Structural and functional characterization of a cold-adapted stand-alone TPM domain reveals a relationship between dynamics and phosphatase activity.

    Science.gov (United States)

    Pellizza, Leonardo A; Smal, Clara; Ithuralde, Raúl E; Turjanski, Adrián G; Cicero, Daniel O; Arán, Martín

    2016-12-01

    The TPM domain constitutes a family of recently characterized protein domains that are present in most living organisms. Although some progress has been made in understanding the cellular role of TPM-containing proteins, the relationship between structure and function is not clear yet. We have recently solved the solution and crystal structure of one TPM domain (BA42) from the Antarctic bacterium Bizionia argentinensis. In this work, we demonstrate that BA42 has phosphoric-monoester hydrolase activity. The activity of BA42 is strictly dependent on the binding of divalent metals and retains nearly 70% of the maximum at 4 °C, a typical characteristic of cold-adapted enzymes. From HSQC, 15 N relaxation measurements, and molecular dynamics studies, we determine that the flexibility of the crossing loops was associated to the protein activity. Thermal unfolding experiments showed that the local increment in flexibility of Mg 2+ -bound BA42, when compared with Ca 2+ -bound BA42, is associated to a decrease in global protein stability. Finally, through mutagenesis experiments, we unambiguously demonstrate that the region comprising the metal-binding site participates in the catalytic mechanism. The results shown here contribute to the understanding of the relationship between structure and function of this new family of TPM domains providing important cues on the regulatory role of Mg 2+ and Ca 2+ and the molecular mechanism underlying enzyme activity at low temperatures. © 2016 Federation of European Biochemical Societies.

  20. Laser activation of diamond surface for electroless metal plating

    Science.gov (United States)

    Pimenov, S. M.; Shafeev, G. A.; Laptev, V. A.; Loubnin, E. N.

    1994-04-01

    Selective area electroless nickel and copper deposition onto the surface of diamond single crystals and polycrystalline diamond films has been realized. Three methods of laser-assisted activation of diamond surface were applied: (i) prenucleation of diamond surface with a thin layer of palladium catalyst via laser-induced decomposition of a palladium acetyl-acetonate [Pd(acac)2] solid film; (ii) deposition of palladium by means of the decomposition of Pd(acac)2 dissolved in dimethylformamide; (iii) laser-induced damage of diamond surface.

  1. Research on Phosphatases of Belladona Leaves and Their Purification (Part 1

    Directory of Open Access Journals (Sweden)

    M. Khorsand

    1956-12-01

    Full Text Available Belladona leaves as well as all other studied leaves contains two distinct phosphatase fractions belonging respectively to types II and IIIi the major parts of these enzymes is extraetible by water. It was not possible to extract the non soluble fraction which is solidly retained by the cellular constituents. Phosphatase II does not differ from other phosphatnses of the same type. Whereas phosphatase III is distinetely different from enzymes of the same type of vegetal or animal origins. It is activated by bivalent metallic ions which are specific activators of the alkaline phcspbatnses: Mg-Zn-Ni and Co.

  2. Alkaline Phosphatase: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/alkalinephosphatase.html Alkaline Phosphatase To use the sharing features on this page, please enable JavaScript. What is an Alkaline Phosphatase Test? An alkaline phosphatase (ALP) test measures ...

  3. Identical phosphatase mechanisms achieved through distinct modes of binding phosphoprotein substrate

    Energy Technology Data Exchange (ETDEWEB)

    Pazy, Y.; Motaleb, M.A.; Guarnieri, M.T.; Charon, N.W.; Zhao, R.; Silversmith, R.E. (WVU); (UNC); (Colorado); (EC Uni.)

    2010-04-05

    Two-component signal transduction systems are widespread in prokaryotes and control numerous cellular processes. Extensive investigation of sensor kinase and response regulator proteins from many two-component systems has established conserved sequence, structural, and mechanistic features within each family. In contrast, the phosphatases which catalyze hydrolysis of the response regulator phosphoryl group to terminate signal transduction are poorly understood. Here we present structural and functional characterization of a representative of the CheC/CheX/FliY phosphatase family. The X-ray crystal structure of Borrelia burgdorferi CheX complexed with its CheY3 substrate and the phosphoryl analogue BeF{sub 3}{sup -} reveals a binding orientation between a response regulator and an auxiliary protein different from that shared by every previously characterized example. The surface of CheY3 containing the phosphoryl group interacts directly with a long helix of CheX which bears the conserved (E - X{sub 2} - N) motif. Conserved CheX residues Glu96 and Asn99, separated by a single helical turn, insert into the CheY3 active site. Structural and functional data indicate that CheX Asn99 and CheY3 Thr81 orient a water molecule for hydrolytic attack. The catalytic residues of the CheX-CheY3 complex are virtually superimposable on those of the Escherichia coli CheZ phosphatase complexed with CheY, even though the active site helices of CheX and CheZ are oriented nearly perpendicular to one other. Thus, evolution has found two structural solutions to achieve the same catalytic mechanism through different helical spacing and side chain lengths of the conserved acid/amide residues in CheX and CheZ.

  4. Enhancement of Osteoblastic-Like Cell Activity by Glow Discharge Plasma Surface Modified Hydroxyapatite/β-Tricalcium Phosphate Bone Substitute

    Directory of Open Access Journals (Sweden)

    Eisner Salamanca

    2017-11-01

    Full Text Available Glow discharge plasma (GDP treatments of biomaterials, such as hydroxyapatite/β-tricalcium phosphate (HA/β-TCP composites, produce surfaces with fewer contaminants and may facilitate cell attachment and enhance bone regeneration. Thus, in this study we used argon glow discharge plasma (Ar-GDP treatments to modify HA/β-TCP particle surfaces and investigated the physical and chemical properties of the resulting particles (HA/β-TCP + Ar-GDP. The HA/β-TCP particles were treated with GDP for 15 min in argon gas at room temperature under the following conditions: power: 80 W; frequency: 13.56 MHz; pressure: 100 mTorr. Scanning electron microscope (SEM observations showed similar rough surfaces of HA/β-TCP + Ar-GDP HA/β-TCP particles, and energy dispersive spectrometry analyses showed that HA/β-TCP surfaces had more contaminants than HA/β-TCP + Ar-GDP surfaces. Ca/P mole ratios in HA/β-TCP and HA/β-TCP + Ar-GDP were 1.34 and 1.58, respectively. Both biomaterials presented maximal intensities of X-ray diffraction patterns at 27° with 600 a.u. At 25° and 40°, HA/β-TCP + Ar-GDP and HA/β-TCP particles had peaks of 200 a.u., which are similar to XRD intensities of human bone. In subsequent comparisons, MG-63 cell viability and differentiation into osteoblast-like cells were assessed on HA/β-TCP and HA/β-TCP + Ar-GDP surfaces, and Ar-GDP treatments led to improved cell growth and alkaline phosphatase activities. The present data indicate that GDP surface treatment modified HA/β-TCP surfaces by eliminating contaminants, and the resulting graft material enhanced bone regeneration.

  5. Surface-activated joining method for surveillance coupon reconstitution

    International Nuclear Information System (INIS)

    Kaihara, Shoichiro; Nakamura, Terumi

    1993-01-01

    As nuclear power plants approach the end of their license periods and license renewal is contemplated, there is an increasing need to expand the data base of mechanical properties obtainable from archival surveillance specimens. A new joining method for reconstituting broken Charpy specimens is being developed, the objective being to retain the original properties of the material in the process. The new method is called surface-activated joining (SAJ). It is designed to obtain a good junction without applying extra heating and deformation. In particular, the purpose of SAJ is to minimize the width of the heat-affected zone (HAZ) and to decrease the maximum temperature experienced by the specimen during reconsolidation of the two pieces. Generally, machined metal surfaces are contaminated with films of oxide, adsorbed gas, oil, or other vapors that impede bonding of surfaces during joining. However, if surface contamination is removed and the two surfaces are mated as closely as possible, joining can be achieved at low temperatures and modest stress levels. In order to apply the SAJ method, the following requirements must be met: (1) inert atmosphere to protect the surfaces from atmospheric gases and oxidation; (2) removal of the existing contamination layers to activate the surfaces; and (3) method for bringing the two surfaces into very intimate contact prior to joining

  6. Surface activity, lipid profiles and their implications in cervical cancer.

    Directory of Open Access Journals (Sweden)

    Preetha A

    2005-01-01

    Full Text Available Background: The profiles of lipids in normal and cancerous tissues may differ revealing information about cancer development and progression. Lipids being surface active, changes in lipid profiles can manifest as altered surface activity profiles. Langmuir monolayers offer a convenient model for evaluating surface activity of biological membranes. Aims: The aims of this study were to quantify phospholipids and their effects on surface activity of normal and cancerous human cervical tissues as well as to evaluate the role of phosphatidylcholine (PC and sphingomyelin (SM in cervical cancer using Langmuir monolayers. Methods and Materials: Lipid quantification was done using thin layer chromatography and phosphorus assay. Surface activity was evaluated using Langmuir monolayers. Monolayers were formed on the surface of deionized water by spreading tissue organic phase corresponding to 1 mg of tissue and studying their surface pressure-area isotherms at body temperature. The PC and SM contents of cancerous human cervical tissues were higher than those of the normal human cervical tissues. Role of PC and SM were evaluated by adding varying amounts of these lipids to normal cervical pooled organic phase. Statistical analysis: Student′s t-test (p < 0.05 and one-way analysis of variance (ANOVA was used. Results: Our results reveals that the phosphatidylglycerol level in cancerous cervical tissue was nearly five folds higher than that in normal cervical tissue. Also PC and sphingomyelin SM were found to be the major phospholipid components in cancerous and normal cervical tissues respectively. The addition of either 1.5 µg DPPC or 0.5 µg SM /mg of tissue to the normal organic phase changed its surface activity profile to that of the cancerous tissues. Statistically significant surface activity parameters showed that PC and SM have remarkable roles in shifting the normal cervical lipophilic surface activity towards that of cancerous lipophilic

  7. Recent advances in understanding the role of protein-tyrosine phosphatases in development and disease

    NARCIS (Netherlands)

    Hale, Alexander James; Ter Steege, Eline; den Hertog, Jeroen

    2017-01-01

    Protein-tyrosine phosphatases (PTPs) remove phosphate groups from tyrosine residues, and thereby propagate or inhibit signal transduction, and hence influence cellular processes such as cell proliferation and differentiation. The importance of tightly controlled PTP activity is reflected by the

  8. Protein phosphatase 2A in stretch-induced endothelial cell proliferation

    Science.gov (United States)

    Murata, K.; Mills, I.; Sumpio, B. E.

    1996-01-01

    We previously proposed that activation of protein kinase C is a key mechanism for control of cell growth enhanced by cyclic strain [Rosales and Sumpio (1992): Surgery 112:459-466]. Here we examined protein phosphatase 1 and 2A activity in bovine aortic endothelial cells exposed to cyclic stain. Protein phosphatase 2A activity in the cytosol was decreased by 36.1% in response to cyclic strain for 60 min, whereas the activity in the membrane did not change. Treatment with low concentration (0.1 nM) of okadaic acid enhanced proliferation of both static and stretched endothelial cells in 10% fetal bovine serum. These data suggest that protein phosphatase 2A acts as a growth suppressor and cyclic strain may enhance cellular proliferation by inhibiting protein phosphatase 2A as well as stimulating protein kinase C.

  9. Safety, Tolerability, and Preliminary Activity of LB-100, an Inhibitor of Protein Phosphatase 2A, in Patients with Relapsed Solid Tumors: An Open-Label, Dose Escalation, First-in-Human, Phase I Trial.

    Science.gov (United States)

    Chung, Vincent; Mansfield, Aaron S; Braiteh, Fadi; Richards, Donald; Durivage, Henry; Ungerleider, Richard S; Johnson, Francis; Kovach, John S

    2017-07-01

    Purpose: To determine the MTD and to assess the safety, tolerability, and potential activity of LB-100, a first-in-class small-molecule inhibitor of protein phosphatase 2A (PP2A) in adult patients with progressive solid tumors. Experimental Design: LB-100 was administered intravenously daily for 3 days in 21-day cycles in a 3 + 3 dose escalation design. Results: There were 29 patient entries over 7 dose escalations. One patient stopped treatment after one dose because of an acute infection and was reenrolled after recovery; each course was analyzed as a separate patient entry. Two patients had dose-limiting toxicity (reversible increases in serum creatinine or calculated serum creatinine clearance) at the 3.1 mg/m 2 level. Probable or possible study drug-related grade 3 adverse events occurred in 6 (20.7%) patients [anemia ( n = 2), decreased creatinine clearance, dyspnea, hyponatremia, and lymphopenia]. Ten (50%) of 20 response-evaluable patients had stable disease for four or more cycles. One patient with pancreatic adenocarcinoma had a partial response noted after 10 cycles, which was maintained for five additional cycles. The other patients achieving stable disease had one of the following: fibrosarcoma, chondrosarcoma, thymoma, atypical carcinoid of lung, or ovarian, testicular, breast ( n = 2), and prostate cancer. The recommended phase II dose of LB-100 is 2.33 mg/m 2 daily for 3 days every 3 weeks. Conclusions: The safety, tolerability, preliminary evidence of antitumor activity, and novel mechanism of action of LB-100 support its continued development alone and in combination with other therapies. Clin Cancer Res; 23(13); 3277-84. ©2016 AACR . ©2016 American Association for Cancer Research.

  10. HLA-F is a surface marker on activated lymphocytes.

    Science.gov (United States)

    Lee, Ni; Ishitani, Akiko; Geraghty, Daniel E

    2010-08-01

    Of the three nonclassical class I antigens expressed in humans, HLA-F has been least characterized with regard to expression or function. In this study, we examined HLA-F expression focusing on lymphoid cells, where our previous work with homologous cell lines had demonstrated surface HLA-F expression. HLA-F protein expression was observed by Western blot analysis in all resting lymphocytes, including B cells, T cells, NK cells, and monocytes, all of which lacked surface expression in the resting state. Upon activation, using a variety of methods to activate different lymphocyte subpopulations, all cell types that expressed HLA-F intracellularly showed an induction of surface HLA-F protein. An examination of peripheral blood from individuals genetically deficient for TAP and tapasin expression demonstrated the same activation expression profiles for HLA-F,but with altered kinetics post-activation. Further analysis of CD41+CD25+1 Treg showed that HLA-F was not upregulated on the major fraction of these cells when they were activated,whereas CD41+CD25- T cells showed strong expression of surface HLA-F when activated under identical conditions. These findings are discussed with regard to possible functions for HLA-F and its potential clinical use as a marker of an activated immune response.

  11. Synthesis and surface active properties of cationic surface active agents from crude rice bran oil

    Directory of Open Access Journals (Sweden)

    El-Dougdoug, W. I. A.

    1999-10-01

    Full Text Available Cationic surfactants of 2-hidroxy-3-(2- alkylamidopolyethyl amino propane-1-triethylammonium hydroxides (ix-xuia-d were prepared from fatty acids (ia-d [palmitic, stearic, oleic, linoleic acid] and mixed fatty acids of crude rice bran oil ie [RBO]. The reaction of these acids with ethylenediamine, diethylenetriamine, triethylenetetramine andletraethylenepentamine (iia-d produced (iii-viia-d. The produced amidopolyethylamine (iii-viia-d reacted with 2-epoxypropylenetriethylammonium chloride (viii to give the cationic surfactants (ix-xiiia-d . The produced derivatives were purified and characterized by microanalysis, molecular weight determination, infra-red (IR, and proton nuclear magnetic resonance (1H NMR spectra. The surface active properties and inhibition efficiency of the prepared cationic surfactants were determined.

    Se han preparado tensioactivos catiónicos de hidróxidos de! 2-hidroxi-3-(2-alquilamidopolietilamino propano-1;trietilamonio (ix-xiiia-d a partir de los ácidos grasos (ia-d [ácido palmítico, esteárico, oleico y linoleico] y mezclas de ácidos grasos de aceite de germen de arroz crudo ie [RBO]. La reacción de estos ácidos con etilenodiamina, dietilenotriamina, trietilenotetramina y tetraetilenopentamina (iia-d produjo los compuestos (iv-viia-d . Los amidopolietilaminos producidos (iii-viia-d reaccionaron con el cloruro de 2-epoxipropilenotrietilamonio (viii para dar los tensioactivos catiónicos (ix-xiiia-d. Los derivados producidos se purificaron y caracterizaron por microanálisis, determinación del peso molecular, espectros de infrarrojo (IR y resonancia magnética nuclear de protón (1H NMR. Se determinaron las propiedades tensioactivas y la eficacia de inhibición de los tensioactivos cati

  12. Mechanochemical activation and gallium and indiaarsenides surface catalycity

    Science.gov (United States)

    Kirovskaya, I. A.; Mironova, E. V.; Umansky, I. V.; Brueva, O. Yu; Murashova, A. O.; Yureva, A. V.

    2018-01-01

    The present work has been carried out in terms of determining the possibilities for a clearer identification of the active sites nature, intermediate surface compounds nature, functional groups during adsorption and catalysis, activation of the diamond-like semiconductors surface (in particular, the AIIIBV type) based on mechanochemical studies of the “reaction medium (H2O, iso-C3H7OH) - dispersible semiconductor (GaAs, InAs)” systems. As a result, according to the read kinetic curves of dispersion in water, both acidification and alkalinization of the medium have been established and explained; increased activity of the newly formed surface has been noted; intermediate surface compounds, functional groups appearing on the real surface and under H2O adsorption conditions, adsorption and catalytic decomposition of iso-C3H7OH have been found (with explanation of the origin). The unconcealed role of coordinatively unsaturated atoms as active sites of these processes has been shown; the relative catalytic activity of the semiconductors studied has been evaluated. Practical recommendations on the preferred use of gallium arsenide in semiconductor gas analysis and semiconductor catalysis have been given in literature searches, great care should be taken in constructing both.

  13. Effects of sub-lethal dose of gamma-irradiation on levels of acid phosphatase in cerebellum of pigeons

    International Nuclear Information System (INIS)

    Shah, V.C.; Gadhia, P.K.

    1980-01-01

    The changes in the activities of acid phosphatase in the sham-irradiated and γ-irradiated cerebellum of pigeons have been studied both biochemically as well as histochemically after 400 rads. The specific activity of acid phosphatase decreased significantly after 48h and 72h of irradiation. The histochemical observations following total body irradiation confirmed the results obtained by quantitative biochemical studies. (author)

  14. Atomic and molecular layer activation of dielectric surfaces

    Science.gov (United States)

    Senkevich, John Joseph

    Strong interaction between the material deposit and substrate is critical to stable deposits and interfaces. The work presented here focuses on the surface activation of dielectric surfaces and oxidized metal surfaces to promote the chemisorption of palladium (II) hexafluoroacetylacetonate (PdII (hfac)2). The goal is to develop reliable, robust metallization protocols, which enable strong interactions between the metal and substrate. SiO2, air exposed Ta, Trikon, and SiLK were activated with sulfur or phosphorus. Two types of activations were developed; one based on self-assembled chemistry, and the other a plasma-assisted process. Activation of the surface using self-assembly techniques was carried out using mercaptan-terminated silane and tetrasulfide silane. The resulting films were characterized by variable angle spectroscopic ellipsometry, contact angle goniometry, and X-ray photoelectron spectroscopy. Tetrasulfide silane sources films exhibit self-limiting behavior, even in the presence of water vapor; whereas mercaptan-terminated silane sourced films tend to be thicker. The surface activations using atomic layers of sulfur and phosphorus were carried out in a rf plasma chamber using hydrogen sulfide and phosphine sources, respectively. The activations were studied as functions of rf power, system pressure, and substrate material. Results show that higher rf powers and lower system pressures promote greater surface coverages by sulfur with a reduced oxidation state. The activated dielectrics show evidence of PdII(hfac)2 chemisorption, in contrast to non-activated surfaces. The binding energy shift of the Pd3d 5/2 XPS peak towards elemental Pd provides evidence for the dissociative chemisorption of PdII(hfac)2. The extent of dissociation depends on the substrate temperature and the activation method used. The conclusions of the work presented here have implications for metallization using highly polarizable transition metals. Specifically, it can be applied to

  15. Protein Phosphatase Methyl-Esterase PME-1 Protects Protein Phosphatase 2A from Ubiquitin/Proteasome Degradation.

    Science.gov (United States)

    Yabe, Ryotaro; Miura, Akane; Usui, Tatsuya; Mudrak, Ingrid; Ogris, Egon; Ohama, Takashi; Sato, Koichi

    2015-01-01

    Protein phosphatase 2A (PP2A) is a conserved essential enzyme that is implicated as a tumor suppressor based on its central role in phosphorylation-dependent signaling pathways. Protein phosphatase methyl esterase (PME-1) catalyzes specifically the demethylation of the C-terminal Leu309 residue of PP2A catalytic subunit (PP2Ac). It has been shown that PME-1 affects the activity of PP2A by demethylating PP2Ac, but also by directly binding to the phosphatase active site, suggesting loss of PME-1 in cells would enhance PP2A activity. However, here we show that PME-1 knockout mouse embryonic fibroblasts (MEFs) exhibit lower PP2A activity than wild type MEFs. Loss of PME-1 enhanced poly-ubiquitination of PP2Ac and shortened the half-life of PP2Ac protein resulting in reduced PP2Ac levels. Chemical inhibition of PME-1 and rescue experiments with wild type and mutated PME-1 revealed methyl-esterase activity was necessary to maintain PP2Ac protein levels. Our data demonstrate that PME-1 methyl-esterase activity protects PP2Ac from ubiquitin/proteasome degradation.

  16. Emerging issues in receptor protein tyrosine phosphatase function: lifting fog or simply shifting?

    DEFF Research Database (Denmark)

    Petrone, A; Sap, J

    2000-01-01

    Transmembrane (receptor) tyrosine phosphatases are intimately involved in responses to cell-cell and cell-matrix contact. Several important issues regarding the targets and regulation of this protein family are now emerging. For example, these phosphatases exhibit complex interactions...... with signaling pathways involving SRC family kinases, which result from their ability to control phosphorylation of both activating and inhibitory sites in these kinases and possibly also their substrates. Similarly, integrin signaling illustrates how phosphorylation of a single protein, or the activity...

  17. Effects of Surface Treatment of Activated Carbon on Its Surface and Cr(VI) Adsorption Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Jin; Jang, Yu Sin [Advanced Materials Division., Korea Research Institute of Chimical Technology, Taejon (Korea)

    2001-04-01

    In this work, the effect of surface treatments on activated carbons (ACs) has been studied in the context of gas and liquid adsorption behaviors. The chemical solutions used in this experiment were 35% sodium hydroxide, and these were used for the acidic and basic treatments, respectively. The surface properties have been determined by pH, acid-base values, and FT-IR. The adsorption isotherms of Cr(VI) ion on activated carbons have been studied with the 5 mg/l concentration at ambient temperature. N{sub 2} adsorption isotherm characteristics, which include the specific surface area, micro pore volume, and microporosity, were determined by BET and Boer's-plot methods. In case of the acidic treatment of activated carbons, it was observed that the adsorption of Cr(VI) ion was more effective due to the increase acid value (or acidic functional group) of activated carbon surfaces. However, the basic treatment on activated carbons was caused no significant effects, probably due to the decreased specific surface area and total pore volume. 27 refs., 7 figs., 4 tabs.

  18. Response surface optimisation for activation of bentonite with microwave irradiation

    Directory of Open Access Journals (Sweden)

    Rožić Ljiljana S.

    2011-01-01

    Full Text Available In this study, the statistical design of the experimental method was applied on the acid activation process of bentonite with microwave irradiation. The influence of activation parameters (time, acid normality and microwave heating power on the selected process response of the activated bentonite samples was studied. The specific surface area was chosen for the process response, because the chemical, surface and structural properties of the activated clay determine and limit its potential applications. The relationship of various process parameters with the specific surface area of bentonite was examined. A mathematical model was developed using a second-order response surface model (RSM with a central composite design incorporating the above mentioned process parameters. The mathematical model developed helped in predicting the variation in specific surface area of activated bentonite with time (5-21 min, acid normality (2-7 N and microwave heating power (63-172 W. The calculated regression models were found to be statistically significant at the required range and presented little variability. Furthermore, high values of R2 (0.957 and R2 (adjusted (0.914 indicate a high dependence and correlation between the observed and the predicted values of the response. These high values also indicate that about 96% of the result of the total variation can be explained by this model. In addition, the model shows that increasing the time and acid normality improves the textural properties of bentonites, resulting in increased specific surface area. This model also can be useful for setting an optimum value of the activation parameters for achieving the maximum specific surface area. An optimum specific surface area of 142 m2g-1 was achieved with an acid normality of 5.2 N, activation time of 7.38 min and microwave power of 117 W. Acid activation of bentonite was found to occur faster with microwave irradiation than with conventional heating. Microwave

  19. Linear response theory of activated surface diffusion with interacting adsorbates

    Energy Technology Data Exchange (ETDEWEB)

    Marti' nez-Casado, R. [Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ (United Kingdom); Sanz, A.S.; Vega, J.L. [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rojas-Lorenzo, G. [Instituto Superior de Tecnologi' as y Ciencias Aplicadas, Ave. Salvador Allende, esq. Luaces, 10400 La Habana (Cuba); Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain); Miret-Artes, S., E-mail: s.miret@imaff.cfmac.csic.es [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain)

    2010-05-12

    Graphical abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed. - Abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed.

  20. Low Energy Surface Activation of Zirconia Based Restorations.

    Science.gov (United States)

    Aboushelib, Moustafa N

    2016-03-01

    To evaluate the influence of low energy surface activation technique on the biaxial flexure strength of zirconia frameworks. Zirconia discs were prepared by cutting CAD/CAM zirconia blocks. Sintered discs were airborne particle abraded using one of the following particles: 30 μm alumina particles, 50 μm alumina particles, or modified round edges 30 μm alumina particles at low pressure. Scanning electron microscopy, x-ray diffraction analysis, surface roughness, and biaxial flexure strength tests were performed (n = 20). Fractured specimens were fractographically analyzed (α = 0.05). Low energy surface activation resulted in 7% monoclinic crystallographic transformation, increasing surface roughness from 0.05 to 0.3 μm and in significant increase in biaxial flexure strength (1718 MPa) compared 30 μm (1064 MPa), 50 μm (1210 MPa), and as-sintered specimens (1150 MPa). Low energy surface activation of zirconia specimens improved the biaxial flexure strength of zirconia frameworks without creation of surface damage. Clinical implications: by controlling particle size and shape of alumina, the flexure strength of zirconia restorations could be increased usinglow pressure particle abrasion.

  1. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, cultur...... for determining bacterial activity might provide a means for future monitoring and assessment of microbial water quality in aquaculture farming systems......Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

  2. Active surface system for the new Sardinia Radiotelescope

    Science.gov (United States)

    Orfei, Alessandro; Morsiani, Marco; Zacchiroli, Giampaolo; Maccaferri, Giuseppe; Roda, Juri; Fiocchi, Franco

    2004-09-01

    In this paper we'll describe the active surface system that will be provided on the new Italian radiotelescope being in the phase of erection in the Sardinia Island. SRT (Sardinia Radiotelescope) will be a 64m shaped dish working up to 100GHz by exploiting the active surface facility designed by the authors. This facility will overcome the effects of gravity deformations on the antenna gain and will also be used to re-shape in a parabolic form the primary mirror, in order to avoid large phase error contribution on the antenna gain for the highest frequencies placed on the primary focus. Together with the description of the SRT system, a wide overview will be given regarding our previous installation of an active surface system, that can be seen like a prototype for SRT, mounted on the 32m dish of the Noto antenna.

  3. Biochemistry and structure of phosphoinositide phosphatases

    Directory of Open Access Journals (Sweden)

    Young Yil Bahk

    2013-01-01

    Full Text Available Phosphoinositides are the phosphorylated derivatives ofphosphatidylinositol, and play a very significant role in adiverse range of signaling processes in eukaryotic cells. Anumber of phosphoinositide-metabolizing enzymes, includingphosphoinositide-kinases and phosphatases are involved in thesynthesis and degradation of these phospholipids. Recently,the function of various phosphatases in the phosphatidylinositolsignaling pathway has been of great interest. In thepresent review we summarize the structural insights andbiochemistry of various phosphatases in regulating phosphoinositidemetabolism. [BMB Reports 2013; 46(1: 1-8

  4. Purification and characterization of an alkaline phosphatase induced by phosphorus starvation in common bean (Phaseolus vulgaris L.) roots

    Energy Technology Data Exchange (ETDEWEB)

    Morales, L.; Gutierrez, N.; Maya, V.; Parra, C.; Martinez B, E.; Coello, P., E-mail: pcoello@servidor.unam.mx [UNAM, Facultad de Quimica, Departamento de Bioquimica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2012-07-01

    Two phosphatase isoforms from roots of the common bean (Phaseolus vulgaris L.) showed an increase in activity in response to phosphate deficiency. One of them (APIII) was chosen for further purification through ionic exchange chromatography and preparative electrophoresis. The estimated molecular mass of APIII was 35 kDa by both SDS-Page and gel filtration analyses, suggesting a monomeric form of the active enzyme. The phosphatase was classified as an alkaline phosphatase based on the requirement of ph 8 for optimum catalysis. It not only exhibited broad substrate specificity, with the most activity against pyrophosphate, but also effectively catalyzed the hydrolysis of polyphosphate, glucose-1-phosphate and phospho enol-pyruvate. Activity was completely inhibited by molybdate, vanadate and phosphate but was only partially inhibited by fluoride. Although divalent cations were not essential for the pyro phosphatase activity of this enzyme, the hydrolysis of pyro phosphatase increased substantially in the presence of Mg{sup 2+}.

  5. Purification and characterization of an alkaline phosphatase induced by phosphorus starvation in common bean (Phaseolus vulgaris L.) roots

    International Nuclear Information System (INIS)

    Morales, L.; Gutierrez, N.; Maya, V.; Parra, C.; Martinez B, E.; Coello, P.

    2012-01-01

    Two phosphatase isoforms from roots of the common bean (Phaseolus vulgaris L.) showed an increase in activity in response to phosphate deficiency. One of them (APIII) was chosen for further purification through ionic exchange chromatography and preparative electrophoresis. The estimated molecular mass of APIII was 35 kDa by both SDS-Page and gel filtration analyses, suggesting a monomeric form of the active enzyme. The phosphatase was classified as an alkaline phosphatase based on the requirement of ph 8 for optimum catalysis. It not only exhibited broad substrate specificity, with the most activity against pyrophosphate, but also effectively catalyzed the hydrolysis of polyphosphate, glucose-1-phosphate and phospho enol-pyruvate. Activity was completely inhibited by molybdate, vanadate and phosphate but was only partially inhibited by fluoride. Although divalent cations were not essential for the pyro phosphatase activity of this enzyme, the hydrolysis of pyro phosphatase increased substantially in the presence of Mg 2+ .

  6. Effect of surface wettability caused by radiation induced surface activation on leidenfrost condition

    Energy Technology Data Exchange (ETDEWEB)

    Takamasa, T.; Hazuku, T.; Tamura, N.; Okamoto, K. [Tokyo Univ., Tokyo (Japan); Mishima, K. [Kyoto Univ., Kyoto (Japan); Furuya, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2003-07-01

    Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. From this basis, we investigated surface wettability and Leidenfrost condition using metal oxides irradiated by {gamma}-rays. In our previous study, contact angle, an indicator of macroscopic wettability, of a water droplet on metal oxide at room temperature was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on metal oxide pieces of titanium, Zircaloy No. 4, SUS-304, and copper was improved significantly by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of Radiation Induced Surface Activation (RISA) on heat transferring phenomena, the Leidenfrost condition and quenching of metal oxides irradiated by {gamma}-rays were investigated. In the Leidenfrost experiment, when the temperature of the heating surface reached the wetting limit temperature, water-solid contact vanished because a stable vapor film existed between the droplet and the metal surface; i.e., a Leidenfrost condition obtained. The wetting limit temperature increased with integrated irradiation dose. After irradiation, the wet length and the duration of contact increased, and the contact angle decreased. In the quenching test, high surface wettability, or a highly hydrophilic condition, of a simulated fuel rod made of SUS was achieved, and the quenching velocities were increased up to 20-30% after 300 kGy 60Co {gamma}-ray irradiation.

  7. Mechanism of Hydrophilicity by Radiation-Induced Surface Activation

    Science.gov (United States)

    Honjo, Yoshio; Furuya, Masahiro; Takamasa, Tomoji; Okamoto, Koji

    When a metal oxide is irradiated by gamma rays, the irradiated surface becomes hydrophilic. This surface phenomenon is called as radiation-induced surface activation (RISA) hydrophilicity. In order to investigate gamma ray-induced and photoinduced hydrophilicity, the contact angles of water droplets on a titanium dioxide surface were measured in terms of irradiation intensity and time for gamma rays of cobalt-60 and for ultraviolet rays. Reciprocals of the contact angles increased in proportion to the irradiation time before the contact angles reached its super-hydrophilic state. The irradiation time dependency is equal to each other qualitatively. In addition, an effect of ambient gas was investigated. In pure argon gas, the contact angle remains the same against the irradiation time. This clearly indicates that certain humidity is required in ambient gas to take place of RISA hydrophilicity. A single crystal titanium dioxide (100) surface was analyzed by X-ray photoelectron spectrometry (XPS). After irradiation with gamma rays, a peak was found in the O1s spectrum, which indicates the adsorption of dissociative water to a surface 5-fold coordinate titanium site, and the formation of a surface hydroxyl group. We conclude that the RISA hydrophilicity is caused by chemisorption of the hydroxyl group on the surface.

  8. Polycyclic aromatic hydrocarbon (PAH)-mediated upregulation of hepatic microRNA-181 family promotes cancer cell migration by targeting MAPK phosphatase-5, regulating the activation of p38 MAPK

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mi-Kyung [Center for Integrated Risk Research, Cellular and Molecular Toxicology Laboratory, Korea Institute of Science and Technology (KIST) (Korea, Republic of); School of Life Sciences and Biotechnology, Korea University, Anam-Dong, Seoungbuk-Gu, Seoul 136-701 (Korea, Republic of); Park, Yong-Keun [School of Life Sciences and Biotechnology, Korea University, Anam-Dong, Seoungbuk-Gu, Seoul 136-701 (Korea, Republic of); Ryu, Jae-Chun, E-mail: ryujc@kist.re.kr [Center for Integrated Risk Research, Cellular and Molecular Toxicology Laboratory, Korea Institute of Science and Technology (KIST) (Korea, Republic of)

    2013-11-15

    Growing evidence indicates that changes in microRNA (miRNA) expression in cancer induced by chemical carcinogens play an important role in cancer development and progression by regulating related genes. However, the mechanisms underlying miRNA involvement in hepatocarcinogenesis induced by polycyclic aromatic hydrocarbons (PAHs) remain unclear. Thus, the identification of aberrant miRNA expression during PAH-induced cancer cell migration will lead to a better understanding of the substantial role of miRNAs in cancer progression. In the present study, miRNA expression profiling showed significant upregulation of miR-181a, -181b, and -181d in human hepatocellular carcinoma cells (HepG2 line) exposed to benzo[a]anthracene (BA) and benzo[k]fluoranthene (BF). MAPK phosphatase-5 (MKP-5), a validated miR-181 target that deactivates MAPKs, was markedly suppressed while phosphorylation of p38 MAPK was increased after BA and BF exposure. The migration of HepG2 cells, observed using the scratch wound-healing assay, also increased in a dose-dependent manner. Depletion of miR-181 family members by miRNA inhibitors enhanced the expression of MKP-5 and suppressed the phosphorylation of p38 MAPK. Furthermore, the depletion of the miR-181 family inhibited cancer cell migration. Based on these results, we conclude that the miR-181 family plays a critical role in PAH-induced hepatocarcinogenesis by targeting MKP-5, resulting in the regulation of p38 MAPK activation. - Highlights: • We found significant upregulation of miR-181 family in HCC exposed to BA and BF. • We identified the MKP-5 as a putative target of miR-181 family. • MKP-5 was suppressed while p-P38 was increased after BA and BF exposure. • The migration of HepG2 cells increased in a dose-dependent manner.

  9. Promiscuity and electrostatic flexibility in the alkaline phosphatase superfamily.

    Science.gov (United States)

    Pabis, Anna; Kamerlin, Shina Caroline Lynn

    2016-04-01

    Catalytic promiscuity, that is, the ability of single enzymes to facilitate the turnover of multiple, chemically distinct substrates, is a widespread phenomenon that plays an important role in the evolution of enzyme function. Additionally, such pre-existing multifunctionality can be harnessed in artificial enzyme design. The members of the alkaline phosphatase superfamily have served extensively as both experimental and computational model systems for enhancing our understanding of catalytic promiscuity. In this Opinion, we present key recent computational studies into the catalytic activity of these highly promiscuous enzymes, highlighting the valuable insight they have provided into both the molecular basis for catalytic promiscuity in general, and its implications for the evolution of phosphatase activity. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Surface activation of dyed fabric for cellulase treatment.

    Science.gov (United States)

    Schimper, Christian B; Ibanescu, Constanta; Bechtold, Thomas

    2011-10-01

    Surface activation of fabric made from cellulose fibres, such as viscose, lyocell, modal fibres and cotton, can be achieved by printing of a concentrated NaOH-containing paste. From the concentration of reducing sugars formed in solution, an increase in intensity of the cellulase hydrolysis by a factor of six to eight was observed, which was mainly concentrated at the activated parts of the fabric surface. This method of local activation is of particular interest for modification of materials that have been dyed with special processes to attain an uneven distribution of dyestuff within the yarn cross-section, e.g., indigo ring-dyed denim yarn for jeans production. Fabrics made from regenerated cellulose fibres were used as model substrate to express the effects of surface activation on indigo-dyed material. Wash-down experiments on indigo-dyed denim demonstrated significant colour removal from the activated surface at low overall weight loss of 4-5%. The method is of relevance for a more eco-friendly processing of jeans in the garment industry. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Exploring codon optimization and response surface methodology to express biologically active transmembrane RANKL in E. coli.

    Science.gov (United States)

    Maharjan, Sushila; Singh, Bijay; Bok, Jin-Duck; Kim, Jeong-In; Jiang, Tao; Cho, Chong-Su; Kang, Sang-Kee; Choi, Yun-Jaie

    2014-01-01

    Receptor activator of nuclear factor (NF)-κB ligand (RANKL), a master cytokine that drives osteoclast differentiation, activation and survival, exists in both transmembrane and extracellular forms. To date, studies on physiological role of RANKL have been mainly carried out with extracellular RANKL probably due to difficulties in achieving high level expression of functional transmembrane RANKL (mRANKL). In the present study, we took advantage of codon optimization and response surface methodology to optimize the soluble expression of mRANKL in E. coli. We optimized the codon usage of mRANKL sequence to a preferred set of codons for E. coli changing its codon adaptation index from 0.64 to 0.76, tending to increase its expression level in E. coli. Further, we utilized central composite design to predict the optimum combination of variables (cell density before induction, lactose concentration, post-induction temperature and post-induction time) for the expression of mRANKL. Finally, we investigated the effects of various experimental parameters using response surface methodology. The best combination of response variables was 0.6 OD600, 7.5 mM lactose, 26°C post-induction temperature and 5 h post-induction time that produced 52.4 mg/L of fusion mRANKL. Prior to functional analysis of the protein, we purified mRANKL to homogeneity and confirmed the existence of trimeric form of mRANKL by native gel electrophoresis and gel filtration chromatography. Further, the biological activity of mRANKL to induce osteoclast formation on RAW264.7 cells was confirmed by tartrate resistant acid phosphatase assay and quantitative real-time polymerase chain reaction assays. Importantly, a new finding from this study was that the biological activity of mRANKL is higher than its extracellular counterpart. To the best of our knowledge, this is the first time to report heterologous expression of mRANKL in soluble form and to perform a comparative study of functional properties of both

  12. Exploring codon optimization and response surface methodology to express biologically active transmembrane RANKL in E. coli.

    Directory of Open Access Journals (Sweden)

    Sushila Maharjan

    Full Text Available Receptor activator of nuclear factor (NF-κB ligand (RANKL, a master cytokine that drives osteoclast differentiation, activation and survival, exists in both transmembrane and extracellular forms. To date, studies on physiological role of RANKL have been mainly carried out with extracellular RANKL probably due to difficulties in achieving high level expression of functional transmembrane RANKL (mRANKL. In the present study, we took advantage of codon optimization and response surface methodology to optimize the soluble expression of mRANKL in E. coli. We optimized the codon usage of mRANKL sequence to a preferred set of codons for E. coli changing its codon adaptation index from 0.64 to 0.76, tending to increase its expression level in E. coli. Further, we utilized central composite design to predict the optimum combination of variables (cell density before induction, lactose concentration, post-induction temperature and post-induction time for the expression of mRANKL. Finally, we investigated the effects of various experimental parameters using response surface methodology. The best combination of response variables was 0.6 OD600, 7.5 mM lactose, 26°C post-induction temperature and 5 h post-induction time that produced 52.4 mg/L of fusion mRANKL. Prior to functional analysis of the protein, we purified mRANKL to homogeneity and confirmed the existence of trimeric form of mRANKL by native gel electrophoresis and gel filtration chromatography. Further, the biological activity of mRANKL to induce osteoclast formation on RAW264.7 cells was confirmed by tartrate resistant acid phosphatase assay and quantitative real-time polymerase chain reaction assays. Importantly, a new finding from this study was that the biological activity of mRANKL is higher than its extracellular counterpart. To the best of our knowledge, this is the first time to report heterologous expression of mRANKL in soluble form and to perform a comparative study of functional

  13. Immune complement activation is attenuated by surface nanotopography

    Directory of Open Access Journals (Sweden)

    Elwing H

    2011-10-01

    Full Text Available Mats Hulander1, Anders Lundgren1, Mattias Berglin1, Mattias Ohrlander2, Jukka Lausmaa3,4, Hans Elwing1 1Department of Cell and Molecular Biology/Interface Biophysics, University of Gothenburg, Medicinaregatan 9E, Gothenburg, 2Bactiguard AB, Stockholm, 3SP Technical Research Institute, Boras, 4Biomatcell, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Abstract: The immune complement (IC is a cell-free protein cascade system, and the first part of the innate immune system to recognize foreign objects that enter the body. Elevated activation of the system from, for example, biomaterials or medical devices can result in both local and systemic adverse effects and eventually loss of function or rejection of the biomaterial. Here, the researchers have studied the effect of surface nanotopography on the activation of the IC system. By a simple nonlithographic process, gold nanoparticles with an average size of 58 nm were immobilized on a smooth gold substrate, creating surfaces where a nanostructure is introduced without changing the surface chemistry. The activation of the IC on smooth and nanostructured surfaces was viewed with fluorescence microscopy and quantified with quartz crystal microbalance with dissipation monitoring in human serum. Additionally, the ability of pre-adsorbed human immunoglobulin G (IgG (a potent activator of the IC to activate the IC after a change in surface hydrophobicity was studied. It was found that the activation of the IC was significantly attenuated on nanostructured surfaces with nearly a 50% reduction, even after pre-adsorption with IgG. An increase in surface hydrophobicity blunted this effect. The possible role of the curvature of the nanoparticles for the orientation of adsorbed IgG molecules, and how this can affect the subsequent activation of the IC, are discussed. The present findings are important for further understanding of how surface nanotopography affects complex protein

  14. Light availability may control extracellular phosphatase production in turbid environments

    Czech Academy of Sciences Publication Activity Database

    Rychtecký, Pavel; Řeháková, Klára; Kozlíková, Eliška; Vrba, Jaroslav

    2015-01-01

    Roč. 69, č. 1 (2015), s. 37-44 ISSN 0095-3628 R&D Projects: GA ČR(CZ) GA206/09/0309; GA ČR(CZ) GAP504/11/2177; GA ČR(CZ) GAP504/11/2182 Institutional support: RVO:60077344 Keywords : phytoplankton * phosphatase activity * ELF97 phosphate Subject RIV: DA - Hydrology ; Limnology Impact factor: 3.232, year: 2015

  15. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    International Nuclear Information System (INIS)

    Kaklamani, Georgia; Bowen, James; Mehrban, Nazia; Dong, Hanshan; Grover, Liam M.; Stamboulis, Artemis

    2013-01-01

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N 2 /H 2 ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of C-N, C=N, and C≡N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  16. Src homology phosphotyrosyl phosphatase 2 mediates cisplatin-related drug resistance by inhibiting apoptosis and activating the Ras/PI3K/Akt1/survivin pathway in lung cancer cells.

    Science.gov (United States)

    Tang, Chunlan; Luo, Hu; Luo, Dan; Yang, Heping; Zhou, Xiangdong

    2018-02-01

    decreased in the H446, H446-SHP2-OE and H446/CDDP cells. However, upon Ras RNA interference, the SHP2 expression was not significantly changed, but the expression of Akt1, pAkt1 and survivin was significantly increased in the H446-SHP2-OE and H446/CDDP cells. In conclusion, SHP2 is a new cisplatin resistance-related phosphatase in lung cancer, which inhibits apoptosis by activating the Ras/PI3K/Akt1/survivin signaling pathway.

  17. Searching for the role of protein phosphatases in eukaryotic microorganisms

    Directory of Open Access Journals (Sweden)

    da-Silva A.M.

    1999-01-01

    Full Text Available Preference for specific protein substrates together with differential sensitivity to activators and inhibitors has allowed classification of serine/threonine protein phosphatases (PPs into four major types designated types 1, 2A, 2B and 2C (PP1, PP2A, PP2B and PP2C, respectively. Comparison of sequences within their catalytic domains has indicated that PP1, PP2A and PP2B are members of the same gene family named PPP. On the other hand, the type 2C enzyme does not share sequence homology with the PPP members and thus represents another gene family, known as PPM. In this report we briefly summarize some of our studies about the role of serine/threonine phosphatases in growth and differentiation of three different eukaryotic models: Blastocladiella emersonii, Neurospora crassa and Dictyostelium discoideum. Our observations suggest that PP2C is the major phosphatase responsible for dephosphorylation of amidotransferase, an enzyme that controls cell wall synthesis during Blastocladiella emersonii zoospore germination. We also report the existence of a novel acid- and thermo-stable protein purified from Neurospora crassa mycelia, which specifically inhibits the PP1 activity of this fungus and mammals. Finally, we comment on our recent results demonstrating that Dictyostelium discoideum expresses a gene that codes for PP1, although this activity has never been demonstrated biochemically in this organism.

  18. Spectroscopic Study of the Surface Oxidation of Mechanically Activated Sulphides

    Czech Academy of Sciences Publication Activity Database

    Godočíková, E.; Baláž, P.; Bastl, Zdeněk; Brabec, Libor

    2002-01-01

    Roč. 200, č. 1 (2002), s. 36-47 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z4040901 Keywords : mechanical activation * surface oxidation * sulphide minerals Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.295, year: 2002

  19. Temperature effects on surface activity and application in oxidation ...

    Indian Academy of Sciences (India)

    Unknown

    Surface activity; cetyl trimethylammonium bromide; sodium dodecyl sulfate; temperature; oxidation. 1. Introduction. Cationic systems show strong synergism in their so- lutions and display physicochemical properties that differ distinctly from those of individual surfactants,1 due to their electrostatic interaction between oppo-.

  20. Improved efficiency of budesonide nebulization using surface-active agents

    NARCIS (Netherlands)

    Heijstra, M. P.; Schaefer, N. C.; Duiverman, E. J.; LeSouef, P. N.; Devadason, S. G.

    2006-01-01

    Our aim was to improve the efficiency of nebulised budesonide using surface-active agents. Cationic, anionic, and nonionic detergents were added to commercial budesonide suspension, and the particle size distribution during nebulization was measured using both cascade impaction and laser

  1. Regulation of intestinal calcium absorption by luminal calcium content: role of intestinal alkaline phosphatase.

    Science.gov (United States)

    Brun, Lucas R; Brance, María L; Lombarte, Mercedes; Lupo, Maela; Di Loreto, Verónica E; Rigalli, Alfredo

    2014-07-01

    Intestinal alkaline phosphatase is a brush border enzyme that is stimulated by calcium. Inhibition of intestinal alkaline phosphatase increases intestinal calcium absorption. We hypothesized that intestinal alkaline phosphatase acts as a minute-to-minute regulatory mechanism of calcium entry. The aim of this study was to evaluate the mechanism by which intestinal luminal calcium controls intestinal calcium absorption. We performed kinetic studies with purified intestinal alkaline phosphatase and everted duodenal sacs and showed that intestinal alkaline phosphatase modifies the luminal pH as a function of enzyme concentration and calcium luminal content. A decrease in pH occurred simultaneously with a decrease in calcium absorption. The inhibition of intestinal alkaline phosphatase by l-phenylalanine caused an increase in calcium absorption. This effect was also confirmed in calcium uptake experiments with isolated duodenal cells. Changes in luminal pH arising from intestinal alkaline phosphatase activity induced by luminal calcium concentration modulate intestinal calcium absorption. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Controlling hydrogenation activity and selectivity of bimetallic surfaces and catalysts

    Science.gov (United States)

    Murillo, Luis E.

    Studies of bimetallic systems are of great interest in catalysis due to the novel properties that they often show in comparison with the parent metals. The goals of this dissertation are: (1) to expand the studies of self-hydrogenation and hydrogenation reactions on bimetallic surfaces under ultra high vacuum conditions (UHV) using different hydrocarbon as probe molecules; (2) to attempt to correlate the surface science findings with supported catalyst studies under more realistic conditions; and (3) to investigate the competitive hydrogenation of C=C versus C=O bonds on Pt(111) modified by different 3d transition metals. Hydrogenation studies using temperature programmed desorption (TPD) on Ni/Pt(111) bimetallic surfaces have demonstrated an enhancement in the low temperature hydrogenation activity relative to that of clean Pt(111). This novel hydrogenation pathway can be achieved under UHV conditions by controlling the structures of the bimetallic surfaces. A low temperature hydrogenation activity of 1-hexene and 1-butene has been observed on a Pt-Ni-Pt(111) subsurface structure, where Ni atoms are mainly present on the second layer of the Pt(111) single crystal. These results are in agreement with previous studies of self-hydrogenation and hydrogenation of cyclohexene. However, a much higher dehydrogenation activity is observed in the reaction of cyclohexene to produce benzene, demonstrating that the hydrocarbon structure has an effect on the reaction pathways. On the other hand, self-hydrogenation of 1-butene is not observed on the Pt-Ni-Pt(111) surface, indicating that the chain length (or molecular weight) has a significant effect on the selfhydrogenation activity. The gas phase reaction of cyclohexene on Ni/Pt supported on alumina catalysts has also shown a higher self-hydrogenation activity in comparison with the same reaction performed on supported monometallic catalysts. The effects of metal loading and impregnation sequence of the metal precursors are

  3. Crystallization of recombinant Haemophilus influenzaee (P4) acid phosphatase

    Energy Technology Data Exchange (ETDEWEB)

    Ou, Zhonghui [Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211 (United States); Felts, Richard L. [Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211 (United States); Reilly, Thomas J. [Department of Veterinary Pathobiology and Veterinary Medical Diagnostic Laboratory, University of Missouri-Columbia, Columbia, MO 65211 (United States); Nix, Jay C. [Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Tanner, John J., E-mail: tannerjj@missouri.edu [Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211 (United States); Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211 (United States)

    2006-05-01

    Lipoprotein e (P4) is a class C acid phosphatase and a potential vaccine candidate for nontypeable H. influenzae infections. This paper reports the crystallization of recombinant e (P4) and the acquisition of a 1.7 Å resolution native X-ray diffraction data set. Haemophilus influenzae infects the upper respiratory tract of humans and can cause infections of the middle ear, sinuses and bronchi. The virulence of the pathogen is thought to involve a group of surface-localized macromolecular components that mediate interactions at the host–pathogen interface. One of these components is lipoprotein e (P4), which is a class C acid phosphatase and a potential vaccine candidate for nontypeable H. influenzae infections. This paper reports the crystallization of recombinant e (P4) and the acquisition of a 1.7 Å resolution native X-ray diffraction data set. The space group is P4{sub 2}2{sub 1}2, with unit-cell parameters a = 65.6, c = 101.4 Å, one protein molecule per asymmetric unit and 37% solvent content. This is the first report of the crystallization of a class C acid phosphatase.

  4. 21 CFR 864.7660 - Leukocyte alkaline phosphatase test.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Leukocyte alkaline phosphatase test. 864.7660... Leukocyte alkaline phosphatase test. (a) Identification. A leukocyte alkaline phosphatase test is a device used to identify the enzyme leukocyte alkaline phosphatase in neutrophilic granulocytes (granular...

  5. Crystal Structure of the Catalytic Domain of a Serine Threonine Protein Phosphatase

    Science.gov (United States)

    Swinglel, Mark; Honkanel, Richard; Ciszak, Ewa

    2003-01-01

    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.

  6. Catalytic and substrate promiscuity: distinct multiple chemistries catalysed by the phosphatase domain of receptor protein tyrosine phosphatase.

    Science.gov (United States)

    Srinivasan, Bharath; Marks, Hanna; Mitra, Sreyoshi; Smalley, David M; Skolnick, Jeffrey

    2016-07-15

    The presence of latent activities in enzymes is posited to underlie the natural evolution of new catalytic functions. However, the prevalence and extent of such substrate and catalytic ambiguity in evolved enzymes is difficult to address experimentally given the order-of-magnitude difference in the activities for native and, sometimes, promiscuous substrate/s. Further, such latent functions are of special interest when the activities concerned do not fall into the domain of substrate promiscuity. In the present study, we show a special case of such latent enzyme activity by demonstrating the presence of two mechanistically distinct reactions catalysed by the catalytic domain of receptor protein tyrosine phosphatase isoform δ (PTPRδ). The primary catalytic activity involves the hydrolysis of a phosphomonoester bond (C─O─P) with high catalytic efficiency, whereas the secondary activity is the hydrolysis of a glycosidic bond (C─O─C) with poorer catalytic efficiency. This enzyme also displays substrate promiscuity by hydrolysing diester bonds while being highly discriminative for its monoester substrates. To confirm these activities, we also demonstrated their presence on the catalytic domain of protein tyrosine phosphatase Ω (PTPRΩ), a homologue of PTPRδ. Studies on the rate, metal-ion dependence, pH dependence and inhibition of the respective activities showed that they are markedly different. This is the first study that demonstrates a novel sugar hydrolase and diesterase activity for the phosphatase domain (PD) of PTPRδ and PTPRΩ. This work has significant implications for both understanding the evolution of enzymatic activity and the possible physiological role of this new chemistry. Our findings suggest that the genome might harbour a wealth of such alternative latent enzyme activities in the same protein domain that renders our knowledge of metabolic networks incomplete. © 2016 The Author(s). published by Portland Press Limited on behalf of the

  7. Surface active complexes formed between keratin polypeptides and ionic surfactants.

    Science.gov (United States)

    Pan, Fang; Lu, Zhiming; Tucker, Ian; Hosking, Sarah; Petkov, Jordan; Lu, Jian R

    2016-12-15

    Keratins are a group of important proteins in skin and hair and as biomaterials they can provide desirable properties such as strength, biocompatibility, and moisture regaining and retaining. The aim of this work is to develop water-soluble keratin polypeptides from sheep wool and then explore how their surface adsorption behaves with and without surfactants. Successful preparation of keratin samples was demonstrated by identification of the key components from gel electrophoresis and the reproducible production of gram scale samples with and without SDS (sodium dodecylsulphate) during wool fibre dissolution. SDS micelles could reduce the formation of disulphide bonds between keratins during extraction, reducing inter-molecular crosslinking and improving keratin polypeptide solubility. However, Zeta potential measurements of the two polypeptide batches demonstrated almost identical pH dependent surface charge distributions with isoelectric points around pH 3.5, showing complete removal of SDS during purification by dialysis. In spite of different solubility from the two batches of keratin samples prepared, very similar adsorption and aggregation behavior was revealed from surface tension measurements and dynamic light scattering. Mixing of keratin polypeptides with SDS and C 12 TAB (dodecyltrimethylammonium bromide) led to the formation of keratin-surfactant complexes that were substantially more effective at reducing surface tension than the polypeptides alone, showing great promise in the delivery of keratin polypeptides via the surface active complexes. Neutron reflection measurements revealed the coexistence of surfactant and keratin polypeptides at the interface, thus providing the structural support to the observed surface tension changes associated with the formation of the surface active complexes. Copyright © 2016. Published by Elsevier Inc.

  8. Microstructure and surface properties of lignocellulosic-based activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Garcia, P., E-mail: pegonzal@quim.ucm.es [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040, Madrid (Spain); Centeno, T.A. [Instituto Nacional del Carbon-CSIC, Apartado 73, E-33080 Oviedo (Spain); Urones-Garrote, E. [Centro Nacional de Microscopia Electronica, Universidad Complutense, E-28040, Madrid (Spain); Avila-Brande, D.; Otero-Diaz, L.C. [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040, Madrid (Spain)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Activated carbons were produced by KOH activation at 700 Degree-Sign C. Black-Right-Pointing-Pointer The observed nanostructure consists of highly disordered graphene-like layers with sp{sup 2} bond content Almost-Equal-To 95%. Black-Right-Pointing-Pointer Textural parameters show high surface area ( Almost-Equal-To 1000 m{sup 2}/g) and pore width of 1.3-1.8 nm. Black-Right-Pointing-Pointer Specific capacitance reaches values as high as 161 F/g. - Abstract: Low cost activated carbons have been produced via chemical activation, by using KOH at 700 Degree-Sign C, from the bamboo species Guadua Angustifolia and Bambusa Vulgaris Striata and the residues from shells of the fruits of Castanea Sativa and Juglans Regia as carbon precursors. The scanning electron microscopy micrographs show the conservation of the precursor shape in the case of the Guadua Angustifolia and Bambusa Vulgaris Striata activated carbons. Transmission electron microscopy analyses reveal that these materials consist of carbon platelet-like particles with variable length and thickness, formed by highly disordered graphene-like layers with sp{sup 2} content Almost-Equal-To 95% and average mass density of 1.65 g/cm{sup 3} (25% below standard graphite). Textural parameters indicate a high porosity development with surface areas ranging from 850 to 1100 m{sup 2}/g and average pore width centered in the supermicropores range (1.3-1.8 nm). The electrochemical performance of the activated carbons shows specific capacitance values at low current density (1 mA/cm{sup 2}) as high as 161 F/g in the Juglans Regia activated carbon, as a result of its textural parameters and the presence of pseudocapacitance derived from surface oxygenated acidic groups (mainly quinones and ethers) identified in this activated carbon.

  9. Surface barrier silicon detectors with a large active area

    International Nuclear Information System (INIS)

    Kim, Y.; Husimi, K.; Ikeda, Y.; Kim, C.; Ohkawa, S.; Sakai, T.

    1985-01-01

    Surface barrier silicon detectors with a large active area have been produced by using high resistive n-type silicon crystals, diameters of which are 3 to 5 inches. High quality detectors with a low leakage current and a low noise were achieved by developing the improved surface treatment. Characteristics of detectors obtained are good in energy resolution compared with conventional large area Si(Li) detectors. It has also been confirmed that local dead region is not found from measuring results of photo-pulse injection

  10. Functional immobilization of recombinant alkaline phosphatases bearing a glutamyl donor substrate peptide of microbial transglutaminase.

    Science.gov (United States)

    Kamiya, Noriho; Doi, Satoshi; Tanaka, Yusuke; Ichinose, Hirofumi; Goto, Masahiro

    2007-09-01

    Covalent and site-specific protein immobilization catalyzed by microbial transglutaminase (MTG) was investigated using recombinant Escherichia coli alkaline phosphatase (AP) tagged with a glutamyl donor substrate peptide (MLAQGS) of MTG. A polystyrene surface physically coated with beta-casein or bovine serum albumin (BSA) was employed as an MTG-specific surface displaying reactive lysine residues. MTG-mediated protein immobilization through catalytic epsilon-(gamma-glutamyl)lysine bond formation between the peptide tag of recombinant APs and beta-casein- or BSA-coated surface was verified by the detection of AP activity on the surface. It was found that the length and the insertion position of the peptide tag did not significantly affect the efficacy of enzymatic immobilization of the recombinant APs. On the other hand, pH and ionic strength in the reaction media had crucial effects on the immobilization yields. Interestingly, the optimum pH range of MTG-mediated protein immobilization differed markedly from that for an MTG-catalyzed reaction in aqueous solution. The results suggest that the concentration of reactive species due to electrostatic interaction between the enzyme-substrate intermediate and the protein-adsorbed surface is a key factor governing MTG catalysis at a solid surface.

  11. Nanostructured surface topographies have an effect on bactericidal activity.

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Maniura-Weber, Katharina; Brugger, Juergen; Ren, Qun

    2018-02-28

    Due to the increased emergence of antimicrobial resistance, alternatives to minimize the usage of antibiotics become attractive solutions. Biophysical manipulation of material surface topography to prevent bacterial adhesion is one promising approach. To this end, it is essential to understand the relationship between surface topographical features and bactericidal properties in order to develop antibacterial surfaces. In this work a systematic study of topographical effects on bactericidal activity of nanostructured surfaces is presented. Nanostructured Ormostamp polymer surfaces are fabricated by nano-replication technology using nanoporous templates resulting in 80-nm diameter nanopillars. Six Ormostamp surfaces with nanopillar arrays of various nanopillar densities and heights are obtained by modifying the nanoporous template. The surface roughness ranges from 3.1 to 39.1 nm for the different pillar area parameters. A Gram-positive bacterium, Staphylococcus aureus, is used as the model bacterial strain. An average pillar density at ~ 40 pillars μm -2 with surface roughness of 39.1 nm possesses the highest bactericidal efficiency being close to 100% compared with 20% of the flat control samples. High density structures at ~ 70 pillars μm -2 and low density structures at bactericidal efficiency to almost the level of the control samples. The results obtained here suggests that the topographical effects including pillar density and pillar height inhomogeneity may have significant impacts on adhering pattern and stretching degree of bacterial cell membrane. A biophysical model is prepared to interpret the morphological changes of bacteria on these nanostructures.

  12. Energy expenditure and muscular activation patterns through active sitting on compliant surfaces

    Directory of Open Access Journals (Sweden)

    D. Clark Dickin

    2017-06-01

    Conclusion: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric expenditure. Given the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.

  13. Direct instrumental identification of catalytically active surface sites

    Science.gov (United States)

    Pfisterer, Jonas H. K.; Liang, Yunchang; Schneider, Oliver; Bandarenka, Aliaksandr S.

    2017-09-01

    The activity of heterogeneous catalysts—which are involved in some 80 per cent of processes in the chemical and energy industries—is determined by the electronic structure of specific surface sites that offer optimal binding of reaction intermediates. Directly identifying and monitoring these sites during a reaction should therefore provide insight that might aid the targeted development of heterogeneous catalysts and electrocatalysts (those that participate in electrochemical reactions) for practical applications. The invention of the scanning tunnelling microscope (STM) and the electrochemical STM promised to deliver such imaging capabilities, and both have indeed contributed greatly to our atomistic understanding of heterogeneous catalysis. But although the STM has been used to probe and initiate surface reactions, and has even enabled local measurements of reactivity in some systems, it is not generally thought to be suited to the direct identification of catalytically active surface sites under reaction conditions. Here we demonstrate, however, that common STMs can readily map the catalytic activity of surfaces with high spatial resolution: we show that by monitoring relative changes in the tunnelling current noise, active sites can be distinguished in an almost quantitative fashion according to their ability to catalyse the hydrogen-evolution reaction or the oxygen-reduction reaction. These data allow us to evaluate directly the importance and relative contribution to overall catalyst activity of different defects and sites at the boundaries between two materials. With its ability to deliver such information and its ready applicability to different systems, we anticipate that our method will aid the rational design of heterogeneous catalysts.

  14. Role of phosphatase and tensin homolog deleted on chromosome ten in a rat model of carbon tetrachloride-induced liver fibrosis and the effect of qi-tonifying and blood-activating prescription

    Directory of Open Access Journals (Sweden)

    NIU Xuemin

    2018-01-01

    Full Text Available Objective To investigate the role of phosphatase and tensin homology deleted on chromosome ten (PTEN in a rat model of carbon tetrachloride (CCl4-induced liver fibrosis and the molecular mechanism of action of qi-tonifying and blood-activating prescription in regulating PTEN and inhibiting liver fibrosis. Methods A total of 27 male Wistar rats were randomly divided into three groups, with 9 rats in each group. The rats in liver fibrosis group were treated with CCl4 to establish a model of liver fibrosis, and those in qi-tonifying and blood-activating prescription group were also treated with CCl4 to establish a model and then given a self-made qi-tonifying and blood-activating prescription containing Astragalus membranaceus, Salvia miltiorrhiza, and poria. The rats in the control group were given intraperitoneally injected olive oil. HE staining, Masson staining, and immunohistochemical staining of collagen type I alpha 1 (Col1A1 and collagen type Ⅳ (Col4 were performed to observe the degree of liver fibrosis and collagen deposition; qRT-PCR, immunohistochemistry, and Western blot were used to measure the expression of transforming growth factor-β1 (TGF-β1, PTEN, and downstream genes AKT, mTOR, and p70S6K. A one-way analysis of variance was used for comparison of continuous data between multiple groups and the least significant difference t-test was used for further comparison between any two groups. Results In the liver fibrosis group, liver pathology showed perisinusoidal fibrosis and fibrous tissue proliferation, collagen deposition, and formation of fibrous septum in the portal area; compared with the control group, the liver fibrosis group had significant increases in the mRNA and protein expression of TGF-β1, a significant reduction in the expression of PTEN, and significant increases in the mRNA and phosphorylated protein expression of AKT, mTOR, and p70S6K (all P<0.01. The qi-tonifying and blood-activating prescription group had a

  15. Design parameters for measurements of local catalytic activity on surfaces

    DEFF Research Database (Denmark)

    Johansson, Martin; Johannessen, Tue; Jørgensen, Jan Hoffmann

    2006-01-01

    Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward...... the catalytic surface through the annulus between the tubes, and the gas is sampled close to the surface by the capillary. The influence of various design parameters on the lateral resolution and sensitivity of the measurements is investigated. It is found that the cuter diameter of the annulus sets the upper......, the limits of the range in reaction rate, which can be Studied are estimated. (c) 2005 Elsevier B.V. All rights reserved....

  16. Prophylactic treatment with alkaline phosphatase in cardiac surgery induces endogenous alkaline phosphatase release

    NARCIS (Netherlands)

    Kats, Suzanne; Brands, Ruud; Hamad, Mohamed A. Soliman; Seinen, Willem; Schamhorst, Volkher; Wulkan, Raymond W.; Schoenberger, Jacques P.; van Oeveren, Wim

    Introduction: Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. We assessed the effects of the administration of bovine intestinal alkaline phosphatase (bIAP), an endotoxin detoxifier, on alkaline phosphatase levels

  17. Interaction of Myosin Phosphatase Target Subunit (MYPT1) with Myosin Phosphatase-RhoA Interacting Protein (MRIP): A Role of Glutamic Acids in the Interaction.

    Science.gov (United States)

    Lee, Eunhee; Stafford, Walter F

    2015-01-01

    Scaffold proteins bind to and functionally link protein members of signaling pathways. Interaction of the scaffold proteins, myosin phosphatase target subunit (MYPT1) and myosin phosphatase-RhoA interacting protein (MRIP), causes co-localization of myosin phosphatase and RhoA to actomyosin. To examine biophysical properties of interaction of MYPT1 with MRIP, we employed analytical ultracentrifugation and surface plasmon resonance. In regard to MRIP, its residues 724-837 are sufficient for the MYPT1/MRIP interaction. Moreover, MRIP binds to MYPT1 as either a monomer or a dimer. With respect to MYPT1, its leucine repeat region, LR (residues 991-1030) is sufficient to account for the MYPT1/MRIP interaction. Furthermore, point mutations that replace glutamic acids 998-1000 within LR reduced the binding affinity toward MRIP. This suggests that the glutamic acids of MYPT1 play an important role in the interaction.

  18. Response to DNA damage: why do we need to focus on protein phosphatases?

    Directory of Open Access Journals (Sweden)

    Midori eShimada

    2013-01-01

    Full Text Available Eukaryotic cells are continuously threatened by unavoidable errors during normal DNA replication or various sources of genotoxic stresses that cause DNA damage or stalled replication. To maintain genomic integrity, cells have developed a coordinated signaling network, known as the DNA damage response (DDR. Following DNA damage, sensor molecules detect the presence of DNA damage and transmit signals to downstream transducer molecules. This in turn conveys the signals to numerous effectors, which initiate a large number of specific biological responses, including transient cell cycle arrest mediated by checkpoints, DNA repair, and apoptosis. It is recently becoming clear that dephosphorylation events are involved in keeping DDR factors inactive during normal cell growth. Moreover, dephosphorylation is required to shut off checkpoint arrest following DNA damage and has been implicated in the activation of the DDR. Spatial and temporal regulation of phosphorylation events is essential for the DDR, and fine-tuning of phosphorylation is partly mediated by protein phosphatases. While the role of kinases in the DDR has been well documented, the complex roles of protein dephosphorylation have only recently begun to be investigated. Therefore, it is important to focus on the role of phosphatases and to determine how their activity is regulated upon DNA damage. In this work, we summarize current knowledge on the involvement of serine/threonine phosphatases, especially the protein phosphatase 1, protein phosphatase 2A, and protein phosphatase Mg2+/Mn2+-dependent families, in the DDR.

  19. A selective Seoul-Fluor-based bioprobe, SfBP, for vaccinia H1-related phosphatase--a dual-specific protein tyrosine phosphatase.

    Science.gov (United States)

    Jeong, Myeong Seon; Kim, Eunha; Kang, Hyo Jin; Choi, Eun Joung; Cho, Alvin R; Chung, Sang J; Park, Seung Bum

    2012-07-04

    We report a Seoul-Fluor-based bioprobe, SfBP, for selective monitoring of protein tyrosine phosphatases (PTPs). A rational design based on the structures at the active site of dual-specific PTPs can enable SfBP to selectively monitor the activity of these PTPs with a 93-fold change in brightness. Moreover, screening results of SfBP against 30 classical PTPs and 35 dual-specific PTPs show that it is selective toward vaccinia H1-related (VHR) phosphatase, a dual-specific PTP (DUSP-3).

  20. Fabrication of Bioactive Surfaces by Functionalization of Electroactive and Surface-Active Block Copolymers

    Directory of Open Access Journals (Sweden)

    Omotunde Olubi

    2014-08-01

    Full Text Available Biofunctional block copolymers are becoming increasingly attractive materials as active components in biosensors and other nanoscale electronic devices. We have described two different classes of block copolymers with biofuctional properties. Biofunctionality for block copolymers is achieved through functionalization with appropriate biospecific ligands. We have synthesized block copolymers of electroactive poly(3-decylthiophene and 2-hydroxyethyl methacrylate by atom transfer radical polymerization. The block copolymers were functionalized with the dinitrophenyl (DNP groups, which are capable of binding to Immunoglobulin E (IgE on cell surfaces. The block copolymers were shown to be redox active. Additionally, the triblock copolymer of α, ω-bi-biotin (poly(ethylene oxide-b-poly (styrene-b-poly(ethylene oxide was also synthesized to study their capacity to bind fluorescently tagged avidin. The surface-active property of the poly(ethylene oxide block improved the availability of the biotin functional groups on the polymer surfaces. Fluorescence microscopy observations confirm the specific binding of biotin with avidin.

  1. An electrochemical alkaline phosphatase biosensor fabricated with two DNA probes coupled with λ exonuclease.

    Science.gov (United States)

    Miao, Peng; Ning, Limin; Li, Xiaoxi; Shu, Yongqian; Li, Genxi

    2011-09-15

    In this work we have developed a novel electrochemical biosensor for the detection of alkaline phosphatase (AP) by the use of two complementary DNA probes (DNA 1 and DNA 2) coupled with λ exonuclease (λ exo). Firstly, the 5'-phosphoryl end of DNA 1 is dephosphorylated by AP. Then DNA 1 hybridizes with DNA 2, previously modified on a gold electrode surface. In this double-strand DNA, DNA 2 strand will be promptly cleaved by λ exo with its phosphoryl at the 5' end. After the DNA 2 strand is completely digested, DNA 1 will be released from the double strands and then hybridizes with another DNA 2 strand on the electrode surface, thus the cycle of the release of DNA 1 and the digestion of DNA 2 continues. Since the DNA probes may absorb hexaammineruthenium(III) chloride, the electrochemical species, and the removal of the DNA 2 strand from the electrode surface will result in the decrease of the detected electrochemical signal, which is initially activated by AP, an electrochemical biosensor to assay the activity of AP is proposed in this work. This method may have a linear detection range from 1 to 20 unit/mL with a detection limit of 0.1 unit/mL, and the detection of the enzymatic activity in complex biological fluids can also be realized. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Surface electromyography activity of trunk muscles during wheelchair propulsion.

    Science.gov (United States)

    Yang, Yu-Sheng; Koontz, Alicia M; Triolo, Ronald J; Mercer, Jennifer L; Boninger, Michael L

    2006-12-01

    Trunk instability due to paralysis can have adverse effects on posture and function in a wheelchair. The purpose of this study was to record trunk muscle recruitment patterns using surface electromyography from unimpaired individuals during wheelchair propulsion under various propulsion speed conditions to be able to design trunk muscle stimulation patterns for actual wheelchair users with spinal cord injury. Fourteen unimpaired subjects propelled a test wheelchair on a dynamometer system at two steady state speeds of 0.9 m/s and 1.8 m/s and acceleration from rest to their maximum speed. Lower back/abdominal surface electromyography and upper body movements were recorded for each trial. Based on the hand movement during propulsion, the propulsive cycle was further divided into five stages to describe the activation patterns. Both abdominal and back muscle groups revealed significantly higher activation at early push and pre-push stages when compared to the other three stages of the propulsion phase. With increasing propulsive speed, trunk muscles showed increased activation (Pactivity was significantly higher than abdominal muscle activity across the three speed conditions (PAbdominal and back muscle groups cocontracted at late recovery phase and early push phase to provide sufficient trunk stability to meet the demands of propulsion. This study provides an indication of the amount and duration of stimulation needed for a future application of electrical stimulation of the trunk musculature for persons with spinal cord injury.

  3. Protein phosphatase 2a (PP2A binds within the oligomerization domain of striatin and regulates the phosphorylation and activation of the mammalian Ste20-Like kinase Mst3

    Directory of Open Access Journals (Sweden)

    Jones Candace A

    2011-10-01

    Full Text Available Abstract Background Striatin, a putative protein phosphatase 2A (PP2A B-type regulatory subunit, is a multi-domain scaffolding protein that has recently been linked to several diseases including cerebral cavernous malformation (CCM, which causes symptoms ranging from headaches to stroke. Striatin association with the PP2A A/C (structural subunit/catalytic subunit heterodimer alters PP2A substrate specificity, but targets and roles of striatin-associated PP2A are not known. In addition to binding the PP2A A/C heterodimer to form a PP2A holoenzyme, striatin associates with cerebral cavernous malformation 3 (CCM3 protein, the mammalian Mps one binder (MOB homolog, Mob3/phocein, the mammalian sterile 20-like (Mst kinases, Mst3, Mst4 and STK25, and several other proteins to form a large signaling complex. Little is known about the molecular architecture of the striatin complex and the regulation of these sterile 20-like kinases. Results To help define the molecular organization of striatin complexes and to determine whether Mst3 might be negatively regulated by striatin-associated PP2A, a structure-function analysis of striatin was performed. Two distinct regions of striatin are capable of stably binding directly or indirectly to Mob3--one N-terminal, including the coiled-coil domain, and another more C-terminal, including the WD-repeat domain. In addition, striatin residues 191-344 contain determinants necessary for efficient association of Mst3, Mst4, and CCM3. PP2A associates with the coiled-coil domain of striatin, but unlike Mob3 and Mst3, its binding appears to require striatin oligomerization. Deletion of the caveolin-binding domain on striatin abolishes striatin family oligomerization and PP2A binding. Point mutations in striatin that disrupt PP2A association cause hyperphosphorylation and activation of striatin-associated Mst3. Conclusions Striatin orchestrates the regulation of Mst3 by PP2A. It binds Mst3 likely as a dimer with CCM3 via

  4. Receptor-like protein-tyrosine phosphatase alpha specifically inhibits insulin-increased prolactin gene expression

    DEFF Research Database (Denmark)

    Jacob, K K; Sap, J; Stanley, F M

    1998-01-01

    A physiologically relevant response to insulin, stimulation of prolactin promoter activity in GH4 pituitary cells, was used as an assay to study the specificity of protein-tyrosine phosphatase function. Receptor-like protein-tyrosine phosphatase alpha (RPTPalpha) blocks the effect of insulin...... to increase prolactin gene expression but potentiates the effects of epidermal growth factor and cAMP on prolactin promoter activity. RPTPalpha was the only protein-tyrosine phosphatase tested that did this. Thus, the effect of RPTPalpha on prolactin-chloramphenicol acetyltransferase (CAT) promoter activity...... is specific by two criteria. A number of potential RPTPalpha targets were ruled out by finding (a) that they are not affected or (b) that they are not on the pathway to insulin-increased prolactin-CAT activity. The negative effect of RPTPalpha on insulin activation of the prolactin promoter is not due...

  5. Defining Starch Binding by Glucan Phosphatases

    DEFF Research Database (Denmark)

    Auger, Kyle; Raththagala, Madushi; Wilkens, Casper

    2015-01-01

    Starch is a vital energy molecule in plants that has a wide variety of uses in industry, such as feedstock for biomaterial processing and biofuel production. Plants employ a three enzyme cyclic process utilizing kinases, amylases, and phosphatases to degrade starch in a diurnal manner. Starch...... is comprised of the branched glucan amylopectin and the more linear glucan amylose. Our lab has determined the first structures of these glucan phosphatases and we have defined their enzymatic action. Despite this progress, we lacked a means to quickly and efficiently quantify starch binding to glucan...

  6. Human microsomal glucose-6-phosphatase system.

    Science.gov (United States)

    Nordlie, R C; Sukalski, K A; Johnson, W T

    1993-01-01

    The discovery of glucose-6-phosphatase (EC 3.1.3.9) and of its physiological function in releasing glucose from the liver are discussed briefly. The identification by the Coris of glucose-6-phosphatase deficiency as the underlying defect in certain cases of glycogenosis (type I glycogenosis; von Gierke disease) is described. Characteristics of the catalyst, with a focus on its multiplicity of functions and multicomponent character, are considered with an emphasis on the human liver enzyme. Pioneering studies from the author's laboratory leading to the characterization of two variants of type I glycogenosis, types Ib and Ic, are described.

  7. A description of the BNL active surface analysis facility

    International Nuclear Information System (INIS)

    Tyler, J.W.

    1989-11-01

    Berkeley Nuclear Laboratories has a responsibility for the assessment of radioactive specimens arising both from post irradiation examination of power reactor components and structures and experimental programmes concerned with fission and activation product transport. Existing analytical facilities have been extended with the commissioning of an active surface analysis instrument (XSAM 800pci, Kratos Analytical). Surface analysis involves the characterisation of the outer few atomic layers of a solid surface/interface whose chemical composition and electronic structure will probably be different from the bulk. The new instrument consists three interconnected chambers positioned in series; comprising of a high vacuum sample introduction chamber, an ultra-high vacuum sample treatment/fracture chamber and an ultra-high vacuum sample analysis chamber. The sample analysis chamber contains the electron, X-ray and ion-guns and the electron and ion detectors necessary for performing X-ray photoelectron spectroscopy, scanning Auger microscopy and secondary-ion mass spectroscopy. The chamber also contains a high stability manipulator to enable sub-micron imaging of specimens to be achieved and provide sample heating and cooling between - 180 and 600 0 C. (author)

  8. Nitrate reducing activity pervades surface waters during upwelling

    Science.gov (United States)

    Fernandes, Sheryl Oliveira; Halarnekar, Reena; Malik, Ashish; Vijayan, Vijitha; Varik, Sandesh; Kumari, Ritu; V. K., Jineesh; Gauns, Manguesh U.; Nair, Shanta; LokaBharathi, P. A.

    2014-09-01

    Nitrate reducing activity (NRA) is known to be mediated by microaerophilic to anaerobic bacteria and generally occurs in the sub-surface waters. However, we hypothesize that NRA could become prominent in the surface waters during upwelling. Hence, we examined nitrification and nitrate reduction along with hydrographic and environmental parameters off Trivandrum and Kochi, south-west-India in June 2010. Shoaling isolines of temperature, density, and nutrients revealed the onset of upwelling off Trivandrum. Shoaling of these signatures was absent in the northern transect off Kochi. The degree of nutrient consumption (DNC) was low emphasizing the presence of newly upwelled water off Trivandrum. A significant increase in NRA (df = 1, p < 0.05) was observed off Trivandrum than at Kochi. Moreover, as hypothesized, NRA at Trivandrum was pronounced at the surface with a maximum rate of 0.85 (± 0.02) μmol L1 h- 1 nearshore which was ~ 29 × higher than that at Kochi. Further, an inverse relationship between NRA and NO3- concentration (n = 34, r = - 0.415, p < 0.01) suggested transformation of the upwelled nutrient. Nitrification/NRA was ~ 10 × lower at 0.28 off Trivandrum indicating a discernible shift towards reduction. Such contribution from bacterial activity could be a response towards restoration of homeostasis.

  9. Osteogenic activity of titanium surfaces with hierarchical micro/nano-structures obtained by hydrofluoric acid treatment

    Directory of Open Access Journals (Sweden)

    Liang J

    2017-02-01

    Full Text Available Jianfei Liang,1,* Shanshan Xu,1,* Mingming Shen,2,* Bingkun Cheng,3 Yongfeng Li,4 Xiangwei Liu,1 Dongze Qin,1 Anuj Bellare,5 Liang Kong1 1State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Disease & Shaanxi Key Laboratory of Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi’an, 2Department of Stomatology, Xinhua Hospital of Beijing, Beijing, 3Department of Oral and Maxillofacial Surgery, School of Stomatology, The Second Hospital of Hebei Medical University, Shijiazhuang, 4Department of Stomatology, Chinese PLA 532 Hospital, Huangshan, People’s Republic of China; 5Department of Orthopedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA *These authors contributed equally to this work Abstract: An easier method for constructing the hierarchical micro-/nano-structures on the surface of dental implants in the clinic is needed. In this study, three different titanium surfaces with microscale grooves (width 0.5–1, 1–1.5, and 1.5–2 µm and nanoscale nanoparticles (diameter 20–30, 30–50, and 50–100 nm, respectively were obtained by treatment with different concentrations of hydrofluoric acid (HF and at different etching times (1%, 3 min; 0.5%, 12 min; and 1.5%, 12 min, respectively; denoted as groups HF1, HF2, and HF3. The biological response to the three different titanium surfaces was evaluated by in vitro human bone marrow-derived mesenchymal stem cell (hBMMSC experiments and in vivo animal experiments. The results showed that cell adhesion, proliferation, alkaline phosphatase activity, and mineralization of hBMMSCs were increased in the HF3 group. After the different surface implants were inserted into the distal femurs of 40 rats, the bone–implant contact in groups HF1, HF2, and HF3 was 33.17%±2.2%, 33.82%±3.42%, and 41.04%±3.08%, respectively. Moreover, the maximal pullout

  10. Alkaline phosphatase in boar sperm function.

    Science.gov (United States)

    Bucci, D; Isani, G; Giaretta, E; Spinaci, M; Tamanini, C; Ferlizza, E; Galeati, G

    2014-01-01

    Alkaline phosphatase (AP) catalyses the detachment of phosphate residues from different substrates. Its activity has been demonstrated in seminal plasma and spermatozoa from porcine and other mammalian species; anyway, the role of AP in male reproduction has not been clarified yet and the aim of this study was to determine AP function in boar sperm capacitation and in vitro fertilization (IVF). AP activity was assayed in seminal plasma and in uncapacitated and in vitro capacitated (IVC) spermatozoa; in addition, capacitation was studied in presence of different doses of AP (1.2 and 2.5 IU/mL). The effect of different doses of AP (1.2 and 2.5 IU/mL) on several sperm parameters after IVC (viability, acrosome integrity with FITC-PSA, capacitation status with CTC staining, tyrosine phosphorylation) and on fertilizing ability during IVF were also evaluated. High AP activity was detected in seminal plasma, in particular in sperm-rich fraction; a lower activity was detected in uncapacitated spermatozoa while a significant decrease was evidenced after IVC. Viability was not changed by AP supplementation of the capacitating medium, whereas acrosome integrity and capacitation status were significantly affected by 1.2 and 2.5 doses, with a dose-dependent decrease in acrosome-reacted cells as well as in CTC B pattern displaying cells. As for sperm head protein phosphorylation, a decrease in relative fluorescence was detected in AP 2.5 group, if compared with capacitated one. After IVF, a dose-dependent decrease in penetrated oocytes was recorded, with an increase in monospermic zygote rate. In conclusion, we demonstrated that AP activity decreases under capacitating condition and that addition of AP to spermatozoa during capacitation results in a depression of the capacitating process and IVF. We can infer that AP plays a role in keeping spermatozoa quiescent until they are ejaculated and in modulating the acquisition of the fertilizing ability. © 2013 American Society of

  11. Alkaline phosphatase in developing teeth and bone of man and macaque monkey.

    Science.gov (United States)

    Hasselgren, G

    1978-01-01

    The activity of nonspecific alkaline phosphatase (E.C. 3.1.3.1) in developing teeth and bone of human fetuses and young macaque monkeys has been studied by means of histochemistry. The incubations for alkaline phosphatase were performed at pH 8.2 using naphthol-AS-MX-phosphate as substrate and Fast Blue RR salt or Fast Red Violet LB salt as couplers. By means of pretreatment with heat (56 degrees C), or addition of sodium metavanadate, ortho- or pyrophosphate, two alkaline phosphatases were demonstrated in the developing teeth. Prior to hard tissue formation all alkaline phosphatase activity was inhibited by the addition of vanadate, phosphate, or by pretreatment with heat. Pretreatment with heat or addition of vanadate or phosphate also inhibited alkaline phosphatase activity in the odontoblasts and in the pulpal connective tissue, whereas the activity in the subodontoblastic cell layer, stratum intermedium, outer enamel epithelium, and the the outer cells of the reduced enamel epithelium were much less affected. A week resistant activity was also noted in odontoblasts and pulpal connective tissue.

  12. Human brain pyridoxal-5'-phosphate phosphatase: production and characterization of monoclonal antibodies.

    Science.gov (United States)

    Kim, Dae Won; Eum, Won Sik; Choi, Hee Soon; Kim, So Young; An, Jae Jin; Lee, Sun Hwa; Sohn, Eun Joung; Hwang, Seok-Il; Kwon, Oh-Shin; Kang, Tae-Cheon; Won, Moo Ho; Cho, Sung-Woo; Lee, Kil Soo; Park, Jinseu; Choi, Soo Young

    2005-11-30

    We cloned and expressed human pyridoxal-5\\'-phosphate (PLP) phosphatase, the coenzymatically active form of vitamin B6, in Escherichia coli using pET15b vector. Monoclonal antibodies (mAb) were generated against purified human brain PLP phosphatase in mice, and four antibodies recognizing different epitopes were obtained, one of which inhibited PLP phosphatase. The binding affinities of these four mAbs to PLP phosphatase, as determined using biosensor technology, showed that they had similar binding affinities. Using the anti-PLP phosphatase antibodies as probes, we investigated their cross-reactivities in various mammalian and human tissues and cell lines. The immunoreactive bands obtained on Western blots had molecular masses of ca. 33 kDa. Similarly fractionated extracts of several mammalian cell lines all produced a single band of molecular mass 33 kDa. We believe that these PLP phosphatase mAbs could be used as valuable immunodiagnostic reagents for the detection, identification, and characterization of various neurological diseases related to vitamin B6 abnormalities.

  13. Perspective of surface active agents in baking industry: an overview.

    Science.gov (United States)

    Ahmad, Asif; Arshad, Nazish; Ahmed, Zaheer; Bhatti, Muhammad Shahbaz; Zahoor, Tahir; Anjum, Nomana; Ahmad, Hajra; Afreen, Asma

    2014-01-01

    Different researchers have previously used surfactants for improving bread qualities and revealed that these compounds result in improving the quality of dough and bread by influencing dough strength, tolerance, uniform crumb cell size, and improve slicing characteristics and gas retention. The objective of this review is to highlight the areas where surfactants are most widely used particularly in the bread industries, their role and mechanism of interaction and their contribution to the quality characteristics of the dough and bread. This review reveals some aspects of surface-active agents regarding its role physiochemical properties of dough that in turn affect the bread characteristics by improving its sensory quality and storage stability.

  14. Molluscicidal properties and selective toxicity of surface-active agents

    Science.gov (United States)

    Visser, S. A.

    1965-01-01

    Of over 100 commercially produced surface-active agents tested against the bilharziasis vector snail Biomphalaria sudanica, 13 were found to possess considerable and highly selective molluscicidal properties at concentrations of less than 1 ppm for exposures of 48 hours. Against crustacea, fish, water plants, mosquito larvae, mice, and the eggs of B. sudanica, the toxicities of the 13 surfactants were slight. The chemicals did not appear to be absorbed by organic matter to any appreciable extent. It is thought that the toxicity to B. sudanica is of both a chemical and a physical nature. PMID:5294185

  15. Protein-tyrosine phosphatases in zebrafish gastrulation

    NARCIS (Netherlands)

    van Eekelen, M.J.L.

    2011-01-01

    Protein tyrosine phosphorylation plays a key role in relaying external stimuli and signals into the cell towards the appropriate responses. This process is mediated by protein-tyrosine kinases adding a phosphor group to a tyrosine residue and protein-tyrosine phosphatases removing a phosphor group

  16. Evidence for phosphoprotein phosphatase in Streptomyces granaticolor

    Czech Academy of Sciences Publication Activity Database

    Bobek, J.; Hercík, K.; Dobrová, Zuzana; Branny, Pavel; Nádvorník, Richard; Janeček, Jiří

    2000-01-01

    Roč. 45, č. 4 (2000), s. 310-312 ISSN 0015-5632 R&D Projects: GA ČR GA204/99/1534 Institutional research plan: CEZ:AV0Z5020903 Keywords : streptomycetes * phosphoprotein phosphatase Subject RIV: EE - Microbiology, Virology Impact factor: 0.752, year: 2000

  17. In vitro study of proteins surface activity by tritium probe

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  18. Crystal structure of the human dual specificity phosphatase 1 catalytic domain.

    Science.gov (United States)

    Gumpena, Rajesh; Lountos, George T; Raran-Kurussi, Sreejith; Tropea, Joseph E; Cherry, Scott; Waugh, David S

    2018-02-01

    The dual specificity phosphatase DUSP1 was the first mitogen activated protein kinase phosphatase (MKP) to be identified. It dephosphorylates conserved tyrosine and threonine residues in the activation loops of mitogen activated protein kinases ERK2, JNK1 and p38-alpha. Here, we report the crystal structure of the human DUSP1 catalytic domain at 2.49 Å resolution. Uniquely, the protein was crystallized as an MBP fusion protein in complex with a monobody that binds to MBP. Sulfate ions occupy the phosphotyrosine and putative phosphothreonine binding sites in the DUSP1 catalytic domain. © 2017 The Protein Society.

  19. A new model for the membrane topology of glucose-6-phosphatase: the enzyme involved in von Gierke disease.

    Science.gov (United States)

    Hemrika, W; Wever, R

    1997-06-16

    Very recently we have proposed [Hemrika et al. (1997) Proc. Natl. Acad. Sci. USA 94, 2145-2149] that the active site of the vanadate-containing chloroperoxidase from the fungus Curvularia inaequalis, of which the tertiary structure is known, is structurally very similar to that of the membrane-bound mammalian glucose-6-phosphatases for which no structural data are available. The proposed active site of glucose-6-phosphatase, however, is incompatible with the six transmembrane-helix topology model that is currently used. Here we present a new topology model for glucose-6-phosphatase which is in agreement with all available data.

  20. Osteocalcin and bone-specific alkaline phosphatase in Sickle cell ...

    African Journals Online (AJOL)

    specific alkaline phosphatase (b-AP) total protein levels were evaluated as indicators of bone turnover in twenty patients with sickle cell haemoglobinopathies and in twenty normal healthy individuals. The serum bonespecific alkaline phosphatase ...

  1. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  2. Over-estimation of glucose-6-phosphatase activity in brain in vivo. Apparent difference in rates of [2-3H]glucose and [U-14C]glucose utilization is due to contamination of precursor pool with 14C-labeled products and incomplete recovery of 14C-labeled metabolites

    International Nuclear Information System (INIS)

    Dienel, G.A.; Nelson, T.; Cruz, N.F.; Jay, T.; Crane, A.M.; Sokoloff, L.

    1988-01-01

    Significant dephosphorylation of glucose 6-phosphate due to glucose-6-phosphatase activity in rat brain in vivo was recently reported. The evidence was an apparent more rapid 3 H than 14 C loss from the glucose pool and faster [2- 3 H]glucose than [U- 14 C]glucose utilization following pulse labeling of the brain with [2- 3 H,U- 14 C]glucose. Radiochemical purity of the glucose and quantitative recovery of the labeled products of glucose metabolism isolated from the brain were obviously essential requirements of their study, but no evidence for purity and recovery was provided. When we repeated these experiments with the described isolation procedures, we replicated the results, but found that: 1) the precursor glucose pool contained detritiated, 14 C-labeled contaminants arising from glucose metabolism, particularly 2-pyrrolidone-5-carboxylic acid derived from [ 14 C]glutamine; 2) [ 14 C]glucose metabolite were not quantitatively recovered; 3) the procedure used to isolate the glucose itself produced detritiated, 14 C-labeled derivatives of [2- 3 H,U-14C]glucose. These deficiencies in the isolation procedures could fully account for the observations that were interpreted as evidence of significant glucose 6-phosphate dephosphorylation by glucose-6-phosphatase activity. When glucose was isolated by more rigorous procedures and its purity verified in the present studies, no evidence for such activity in rat brain was found

  3. Gamma-glutamyltransferase, aspartate aminotransferase and alkaline phosphatase as markers of alcohol consumption in out-patient alcoholics

    DEFF Research Database (Denmark)

    Gluud, C; Andersen, I; Dietrichson, O

    1981-01-01

    Serum activity of gamma-glutamyltransferase, aspartate aminotransferase and alkaline phosphatase were determined in 316 patients attending an out-patients clinic for treatment of alcoholism. The activity of gamma-glutamyltransferase was raised in 34% and that of aspartate aminotransferase...... and alkaline phosphatase in 18% and 7%. Neither the activity of gamma-glutamyltransferase, aspartate aminotransferase nor alkaline phosphatase showed any significant (P greater than 0.05) correlation with the history of alcohol consumption. The activities of gamma-glutamyltransferase and aspartate...... aminotransferase were raised significantly more often in patients with recent alcohol consumption than in patients who had abstained for more than 9 days. The concentration of alkaline phosphatase was not significantly (P greater than 0.05) different in these groups. The predictive value of raised and normal...

  4. Phosphoprotein phosphatase of bovine spleen cell nuclei: physicochemical properties

    International Nuclear Information System (INIS)

    Rezyapkin, V.I.; Leonova, L.E.; Komkova, A.I.

    1986-01-01

    The physicochemical properties of phosphoprotein phosphatase (EC 1.3.1.16) from bovine spleen cell nuclei were studied. The enzyme possesses broad substrate specificity and catalyzes the dephosphorylation of phosphocasein, ATP, ADP, and p-nitrophenyl phosphate (pNPP). K/sub m/ for ATP, ADP, and pNPP are equal to 0.44, 0.43, and 1.25 mM, respectively. M/sub r/ of the enzyme, according to the data of gel filtraction of Sephadex G-75 and electrophoresis in polyacrylamide gel of various concentrations is ∼ 33,000. In electrophoresis in the presence of SDS, two protein bands with M/sub r/ 12,000 and 18,000 are detected. In the enzyme molecule, acid amino acid residues predominate; two free SH groups and two disulfide bridges are detected. Phosphoprotein phosphatase is a glycoprotein, containing ∼ 22% carbonhydrates. The protein possesses a supplementary absorption maximum at 560 nm. Ammonium molybdate is a competitive inhibitor with K/sub i/ 0.37 μM, while sodium fluoride is a noncompetitive inhibitor with K/sub i/ 1.3 mM. Incubation in the presence of 2 mM phenylmethylsulfonyl fluoride for 25 h leads to a loss of ∼ 46% of the enzymatic activity. Ammonium molybdate, sodium fluoride, and PMSF are reversible inhibitors. Modifications of the SH groups, NH 2 groups, and histidine leads to a decrease in the enzymatic activity. Incubation of phosphoprotein phosphatase with [γ- 32 P]ATP leads to the incorporation of 0.33 mole 33 P per mole of the enzyme. The mechanism of hydrolysis of the phosphodiester bond, catalyzed by the enzyme, is discussed

  5. Phospholipid-binding Sites of Phosphatase and Tensin Homolog (PTEN)

    Science.gov (United States)

    Wei, Yang; Stec, Boguslaw; Redfield, Alfred G.; Weerapana, Eranthie; Roberts, Mary F.

    2015-01-01

    The lipid phosphatase activity of the tumor suppressor phosphatase and tensin homolog (PTEN) is enhanced by the presence of its biological product, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). This enhancement is suggested to occur via the product binding to the N-terminal region of the protein. PTEN effects on short-chain phosphoinositide 31P linewidths and on the full field dependence of the spin-lattice relaxation rate (measured by high resolution field cycling 31P NMR using spin-labeled protein) are combined with enzyme kinetics with the same short-chain phospholipids to characterize where PI(4,5)P2 binds on the protein. The results are used to model a discrete site for a PI(4,5)P2 molecule close to, but distinct from, the active site of PTEN. This PI(4,5)P2 site uses Arg-47 and Lys-13 as phosphate ligands, explaining why PTEN R47G and K13E can no longer be activated by that phosphoinositide. Placing a PI(4,5)P2 near the substrate site allows for proper orientation of the enzyme on interfaces and should facilitate processive catalysis. PMID:25429968

  6. The Ice Nucleation Activity of Surface Modified Soot

    Science.gov (United States)

    Häusler, Thomas; Witek, Lorenz; Felgitsch, Laura; Hitzenberger, Regina; Grothe, Hinrich

    2017-04-01

    The ice nucleation efficiency of many important atmospheric particles remains poorly understood. Since soot is ubiquitous in the Earth's troposphere, they might have the potential to significantly impact the Earth's climate (Finlayson-Pitts and Pitts, 2000; Seinfeld and Pandis, 1998). Here we present the ice nucleation activity (INA) in immersion freezing mode of different types of soot. Therefor a CAST (combustion aerosol standard) generator was used to produce different kinds of soot samples. The CAST generator combusts a propane-air-mixture and deposits thereby produced soot on a polyvinyl fluoride filter. By varying the propane to air ratio, the amount of organic portion of the soot can be varied from black carbon (BC) with no organic content to brown carbon (BrC) with high organic content. To investigate the impact of functional sites of ice nuclei (IN), the soot samples were exposed to NO2 gas for a certain amount of time (30 to 360 minutes) to chemically modify the surface. Immersion freezing experiments were carried out in a unique reaction gadget. In this device a water-in-oil suspension (with the soot suspended in the aqueous phase) was cooled till the freezing point and was observed through a microscope (Pummer et al., 2012; Zolles et al., 2015) It was found that neither modified nor unmodified BC shows INA. On the contrary, unmodified BrC shows an INA at -32˚ C, which can be increased up to -20˚ C. The INA of BrC depends on the duration of NO2- exposure. To clarify the characteristics of the surface modifications, surface sensitive analysis like infrared spectroscopy and X-ray photoelectron spectroscopy were carried out. Finlayson-Pitts, B. J. and Pitts, J. N. J.: Chemistry of the Upper and Lower Atmosphere, Elsevier, New York, 2000. Pummer, B. G., Bauer, H., Bernardi, J., Bleicher, S., and Grothe, H.: Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen, Atmos Chem Phys, 12, 2541-2550, 2012. Seinfeld, J

  7. Controlled release of biologically active silver from nanosilver surfaces.

    Science.gov (United States)

    Liu, Jingyu; Sonshine, David A; Shervani, Saira; Hurt, Robert H

    2010-11-23

    Major pathways in the antibacterial activity and eukaryotic toxicity of nanosilver involve the silver cation and its soluble complexes, which are well established thiol toxicants. Through these pathways, nanosilver behaves in analogy to a drug delivery system, in which the particle contains a concentrated inventory of an active species, the ion, which is transported to and released near biological target sites. Although the importance of silver ion in the biological response to nanosilver is widely recognized, the drug delivery paradigm has not been well developed for this system, and there is significant potential to improve nanosilver technologies through controlled release formulations. This article applies elements of the drug delivery paradigm to nanosilver dissolution and presents a systematic study of chemical concepts for controlled release. After presenting thermodynamic calculations of silver species partitioning in biological media, the rates of oxidative silver dissolution are measured for nanoparticles and macroscopic foils and used to derive unified area-based release kinetics. A variety of competing chemical approaches are demonstrated for controlling the ion release rate over 4 orders of magnitude. Release can be systematically slowed by thiol and citrate ligand binding, formation of sulfidic coatings, or the scavenging of peroxy-intermediates. Release can be accelerated by preoxidation or particle size reduction, while polymer coatings with complexation sites alter the release profile by storing and releasing inventories of surface-bound silver. Finally, the ability to tune biological activity is demonstrated through a bacterial inhibition zone assay carried out on selected formulations of controlled release nanosilver.

  8. Active-site titration analysis of surface influence on immobilized Candida antarctica Lipase B activity

    Science.gov (United States)

    Matrix morphology and surface polarity effects were investigated for Candida antarctica lipase B immobilization. Measurements of the amount of lipase immobilized (bicinchoninic acid method) and the catalyst’s tributyrin hydrolysis activity, coupled with a determination of the lipase’s functional fr...

  9. Role of MAP Kinase Phosphatase-1 in health and disease | Lawan ...

    African Journals Online (AJOL)

    Mitogen-activated signaling pathways (MAPK) are one of the major and evolutionary conserved signaling pathways involved in protein phosphorylation. Inactivation of MAPK activity is attained by dephosphorylation of either the tyrosine or threonine residues, or both by the actions of MAP kinase phosphatase (MKPs).

  10. Covalent organic polymer functionalization of activated carbon surfaces through acyl chloride for environmental clean-up

    DEFF Research Database (Denmark)

    Mines, Paul D.; Thirion, Damien; Uthuppu, Basil

    2017-01-01

    Nanoporous networks of covalent organic polymers (COPs) are successfully grafted on the surfaces of activated carbons, through a series of surface modification techniques, including acyl chloride formation by thionyl chloride. Hybrid composites of activated carbon functionalized with COPs exhibit...

  11. Mechanical stress-controlled tunable active frequency-selective surface

    Science.gov (United States)

    Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

    2017-01-01

    This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

  12. Self-activated, self-limiting reactions on Si surfaces

    DEFF Research Database (Denmark)

    Morgen, Per; Hvam, Jeanette; Bahari, Ali

    , and the temperatures vary from room temperature to 10000C.The growth is in these cases self-limiting, with the optimal oxide thickness around 0.7-0.8 nm, at 5000C, and up to a few nm for nitride. The self-limiting oxide case was recently predicted by Alex Demkov in a structural optimization to minimise the total...... energy of an oxide system, which happened for an ordered structure, at a thickness of 0.7-0.8 nm. Thus this thin oxide structure has definite crystalline features. We have closely monitored the reaction kinetics with normal x-ray induced photoelectron spectroscopies, and also the structure, composition...... and electrical properties of the system, with surface sensitive, high resolution core level photoelectron spectroscopy. The growth kinetics is well fitted by a Hill function, with parameters, which give information about the character of the process. This function describes a self-activated process. Thus...

  13. A novel broadband bi-mode active frequency selective surface

    Science.gov (United States)

    Xu, Yang; Gao, Jinsong; Xu, Nianxi; Shan, Dongzhi; Song, Naitao

    2017-05-01

    A novel broadband bi-mode active frequency selective surface (AFSS) is presented in this paper. The proposed structure is composed of a periodic array of convoluted square patches and Jerusalem Crosses. According to simulation results, the frequency response of AFSS definitely exhibits a mode switch feature between band-pass and band-stop modes when the diodes stay in ON and OFF states. In order to apply a uniform bias to each PIN diode, an ingenious biasing network based on the extension of Wheatstone bridge is adopted in prototype AFSS. The test results are in good agreement with the simulation results. A further physical mechanism of the bi-mode AFSS is shown by contrasting the distribution of electric field on the AFSS patterns for the two working states.

  14. A novel broadband bi-mode active frequency selective surface

    Directory of Open Access Journals (Sweden)

    Yang Xu

    2017-05-01

    Full Text Available A novel broadband bi-mode active frequency selective surface (AFSS is presented in this paper. The proposed structure is composed of a periodic array of convoluted square patches and Jerusalem Crosses. According to simulation results, the frequency response of AFSS definitely exhibits a mode switch feature between band-pass and band-stop modes when the diodes stay in ON and OFF states. In order to apply a uniform bias to each PIN diode, an ingenious biasing network based on the extension of Wheatstone bridge is adopted in prototype AFSS. The test results are in good agreement with the simulation results. A further physical mechanism of the bi-mode AFSS is shown by contrasting the distribution of electric field on the AFSS patterns for the two working states.

  15. Improved efficiency of budesonide nebulization using surface-active agents.

    Science.gov (United States)

    Bouwman, A M; Heijstra, M P; Schaefer, N C; Duiverman, E J; Lesouëf, P N; Devadason, S G

    2006-01-01

    Our aim was to improve the efficiency of nebulised budesonide using surface-active agents. Cationic, anionic, and nonionic detergents were added to commercial budesonide suspension, and the particle size distribution during nebulization was measured using both cascade impaction and laser diffraction. Our results showed that the emitted dose was increased after addition of cationic (p < 0.001) and nonionic detergents (p < 0.01) compared with the commercial formulation alone. The respirable fraction was increased for all detergent formulations (p < 0.001) compared with the commercial formulation. We concluded that cationic and nonionic detergent increased the total output of budesonide from the Sidestream. All detergent formulations increased the respirable fraction of nebulized budesonide.

  16. A widespread family of serine/threonine protein phosphatases shares a common regulatory switch with proteasomal proteases

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, Niels [Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States; Levdikov, Vladimir M. [Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom; Zimanyi, Christina M. [Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States; Gaudet, Rachelle [Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States; Wilkinson, Anthony J. [Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom; Losick, Richard [Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States

    2017-05-20

    PP2C phosphatases control biological processes including stress responses, development, and cell division in all kingdoms of life. Diverse regulatory domains adapt PP2C phosphatases to specific functions, but how these domains control phosphatase activity was unknown. We present structures representing active and inactive states of the PP2C phosphatase SpoIIE from Bacillus subtilis. Based on structural analyses and genetic and biochemical experiments, we identify an α-helical switch that shifts a carbonyl oxygen into the active site to coordinate a metal cofactor. Our analysis indicates that this switch is widely conserved among PP2C family members, serving as a platform to control phosphatase activity in response to diverse inputs. Remarkably, the switch is shared with proteasomal proteases, which we identify as evolutionary and structural relatives of PP2C phosphatases. Although these proteases use an unrelated catalytic mechanism, rotation of equivalent helices controls protease activity by movement of the equivalent carbonyl oxygen into the active site.

  17. Is alkaline phosphatase the smoking gun for highly refractory primitive leukemic cells?

    Science.gov (United States)

    Rico, Laura G; Juncà, Jordi; Ward, Mike D; Bradford, Jolene; Petriz, Jordi

    2016-11-01

    With the aim to detect candidate malignant primitive progenitor populations, we modified an original alkaline phosphatase (ALP) stem cell detection method based on the identification of alkaline phosphatase fluorescent cells in combination with flow cytometry immunophenotyping. Over a period of one year, we have been using this technique to study its activity in patients with leukemia and lymphoma, showing that changes in the alkaline phosphatase levels can be used to detect rare populations of highly refractory malignant cells. By screening different blood cancers, we have observed that this activity is not always restricted to CD34+ leukemic cells, and can be overexpressed in CD34 negative leukemia. We have verified that this method gives accurate and reproducible measurements and our preliminary results suggest that CD34+/ALPhigh cells appear to sustain leukemogenesis over time.

  18. In Vitro and in Silico Evidence of Phosphatase Diversity in the Biomineralizing Bacterium Ramlibacter tataouinensis

    Directory of Open Access Journals (Sweden)

    Fériel Skouri-Panet

    2018-01-01

    Full Text Available Microbial phosphatase activity can trigger the precipitation of metal-phosphate minerals, a process called phosphatogenesis with global geochemical and environmental implications. An increasing diversity of phosphatases expressed by diverse microorganisms has been evidenced in various environments. However, it is challenging to link the functional properties of genomic repertoires of phosphatases with the phosphatogenesis capabilities of microorganisms. Here, we studied the betaproteobacterium Ramlibacter tataouinensis (Rta, known to biomineralize Ca-phosphates in the environment and the laboratory. We investigated the functional repertoire of this biomineralization process at the cell, genome and molecular level. Based on a mineralization assay, Rta is shown to hydrolyse the phosphoester bonds of a wide range of organic P molecules. Accordingly, its genome has an unusually high diversity of phosphatases: five genes belonging to two non-homologous families, phoD and phoX, were detected. These genes showed diverse predicted cis-regulatory elements. Moreover, they encoded proteins with diverse structural properties according to molecular models. Heterologously expressed PhoD and PhoX in Escherichia coli had different profiles of substrate hydrolysis. As evidenced for Rta cells, recombinant E. coli cells induced the precipitation of Ca-phosphate mineral phases, identified as poorly crystalline hydroxyapatite. The phosphatase genomic repertoire of Rta (containing phosphatases of both the PhoD and PhoX families was previously evidenced as prevalent in marine oligotrophic environments. Interestingly, the Tataouine sand from which Rta was isolated showed similar P-depleted, but Ca-rich conditions. Overall, the diversity of phosphatases in Rta allows the hydrolysis of a broad range of organic P substrates and therefore the release of orthophosphates (inorganic phosphate under diverse trophic conditions. Since the release of orthophosphates is key to the

  19. The Research of Phase Retrieval Holography Method Based on the Active Deformation of the Active Reflector Surface

    Science.gov (United States)

    Wang, Z. Q.; Chen, M. Z.; Pei, X.; Wang, J.

    2017-09-01

    The surface accuracy of a large reflector radio telescope is one of the important factors influencing the performance of the antenna. The effects of panel processing, installation, as well as gravity, temperature, and wind load, will greatly limit the observation efficiency of the antenna. Focused on the technology of active surface which is more accurately controllable than the minor reflector surface of six-ploe, the continuous distribution of active deformation phase factor described by Zernike polynomials is adopted for the first time. Only getting the far field amplitude through adjusting the active surface, the surface error can be detected. By building the models of numerical simulation, the retrieval error of arbitrary surface deformation is calculated, and the retrieval results of surface deformation in a variety of continuous active surface deformation is also studied. It is indicated that this method can stably and accurately detect surface deformation, and can also improve the efficiency of radio telescope observations effectively.

  20. A trial fabrication of activity standard surface sources and positional standard surface sources for an imaging plate system

    International Nuclear Information System (INIS)

    Sato, Yasushi; Hino, Yoshio; Yamada, Takahiro; Matsumoto, Mikio

    2003-01-01

    An imaging plate system can detect low level activity, but quantitative analysis is difficult because there are no adequate standard surface sources. A new fabrication method was developed for standard surface sources by printing on a sheet of paper using an ink-jet printer with inks in which a radioactive material was mixed. The fabricated standard surface sources had high uniformity, high positional resolution arbitrary shapes and a broad intensity range. The standard sources were used for measurement of surface activity as an application. (H. Yokoo)

  1. Rhizobiales-like Phosphatase 2 from Arabidopsis thaliana Is a Novel Phospho-tyrosine-specific Phospho-protein Phosphatase (PPP) Family Protein Phosphatase.

    Science.gov (United States)

    Uhrig, R Glen; Labandera, Anne-Marie; Muhammad, Jamshed; Samuel, Marcus; Moorhead, Greg B

    2016-03-11

    Cellular signaling through protein tyrosine phosphorylation is well established in mammalian cells. Although lacking the classic tyrosine kinases present in humans, plants have a tyrosine phospho-proteome that rivals human cells. Here we report a novel plant tyrosine phosphatase from Arabidopsis thaliana (AtRLPH2) that, surprisingly, has the sequence hallmarks of a phospho-serine/threonine phosphatase belonging to the PPP family. Rhizobiales/Rhodobacterales/Rhodospirillaceae-like phosphatases (RLPHs) are conserved in plants and several other eukaryotes, but not in animals. We demonstrate that AtRLPH2 is localized to the plant cell cytosol, is resistant to the classic serine/threonine phosphatase inhibitors okadaic acid and microcystin, but is inhibited by the tyrosine phosphatase inhibitor orthovanadate and is particularly sensitive to inhibition by the adenylates, ATP and ADP. AtRLPH2 displays remarkable selectivity toward tyrosine-phosphorylated peptides versus serine/threonine phospho-peptides and readily dephosphorylates a classic tyrosine phosphatase protein substrate, suggesting that in vivo it is a tyrosine phosphatase. To date, only one other tyrosine phosphatase is known in plants; thus AtRLPH2 represents one of the missing pieces in the plant tyrosine phosphatase repertoire and supports the concept of protein tyrosine phosphorylation as a key regulatory event in plants. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Radioprotective effect of Panax ginseng on the phosphatases and lipid peroxidation level in testes of Swiss albino mice

    International Nuclear Information System (INIS)

    Kumar, M.; Sharma, M.K.; Saxena, P.S.; Kumar, A.

    2003-01-01

    The Panax ginseng has been used as traditional medicine for past several years among oriental people. The present investigation has been made to assess the radioprotective efficacy of ginseng root extract in the testicular enzymes of Swiss albino mice. The Swiss albino mice were divided into different groups. Ginseng treated group: The animals were administered 10 mg/kg body weight ginseng root extract intraperitoneal (i.p.). Radiation treated group: The animals were exposed to 8 Gy gamma radiation at the dose rate of 1.69 Gy/min at the distance of 80 cm. Combination group: Animals were administered ginseng extract continuously for 4 d and on 4th day they were irradiated to 8 Gy gamma radiation after 30 min of extract administration. The animals from above groups were autopsied on day 1, 3, 7, 14 and 30. Biochemical estimations of acid and alkaline phosphatases and Lipid peroxidation (LPO) in testes were done. In ginseng treated group acid and alkaline phosphatases activity and LPO level did not show any significant alteration. In irradiated animals there was a significant increase in acid phosphatase activity and LPO level. However, significant decline in alkaline phosphatase activity was observed. The treatment of ginseng before irradiation causes significant decrease in acid phosphatase and LPO level and significant increase in alkaline phosphatase activity. One of the cause of radiation damage is lipid peroxidation. Due to lipid peroxidation, lysosomal membrane permeability alters and thus results in release of hydrolytic enzymes. So, an increase in acid phosphatase was noticed after radiation treatment. The alkaline phosphatase activity is associated with membrane permeability and different stages of spermatogenesis. Due to membrane damage and depletion of germ cells of testes after irradiation the enzyme activity was decreased. Ginseng markedly inhibits lipid peroxidation. It acts in indirect fashion to protect radical processes by inhibition of initiation of

  3. Occurrence of Surface Active Agents in the Environment

    Directory of Open Access Journals (Sweden)

    Ewa Olkowska

    2014-01-01

    Full Text Available Due to the specific structure of surfactants molecules they are applied in different areas of human activity (industry, household. After using and discharging from wastewater treatment plants as effluent stream, surface active agents (SAAs are emitted to various elements of the environment (atmosphere, waters, and solid phases, where they can undergo numerous physic-chemical processes (e.g., sorption, degradation and freely migrate. Additionally, SAAs present in the environment can be accumulated in living organisms (bioaccumulation, what can have a negative effect on biotic elements of ecosystems (e.g., toxicity, disturbance of endocrine equilibrium. They also cause increaseing solubility of organic pollutants in aqueous phase, their migration, and accumulation in different environmental compartments. Moreover, surfactants found in aerosols can affect formation and development of clouds, which is associated with cooling effect in the atmosphere and climate changes. The environmental fate of SAAs is still unknown and recognition of this problem will contribute to protection of living organisms as well as preservation of quality and balance of various ecosystems. This work contains basic information about surfactants and overview of pollution of different ecosystems caused by them (their classification and properties, areas of use, their presence, and behavior in the environment.

  4. Functional Analysis of Mouse G6pc1 Mutations Using a Novel In Situ Assay for Glucose-6-Phosphatase Activity and the Effect of Mutations in Conserved Human G6PC1/G6PC2 Amino Acids on G6PC2 Protein Expression.

    Directory of Open Access Journals (Sweden)

    Kayla A Boortz

    Full Text Available Elevated fasting blood glucose (FBG has been associated with increased risk for development of type 2 diabetes. Single nucleotide polymorphisms (SNPs in G6PC2 are the most important common determinants of variations in FBG in humans. Studies using G6pc2 knockout mice suggest that G6pc2 regulates the glucose sensitivity of insulin secretion. G6PC2 and the related G6PC1 and G6PC3 genes encode glucose-6-phosphatase catalytic subunits. This study describes a functional analysis of 22 non-synonymous G6PC2 SNPs, that alter amino acids that are conserved in human G6PC1, mouse G6pc1 and mouse G6pc2, with the goal of identifying variants that potentially affect G6PC2 activity/expression. Published data suggest strong conservation of catalytically important amino acids between all four proteins and the related G6PC3 isoform. Because human G6PC2 has very low glucose-6-phosphatase activity we used an indirect approach, examining the effect of these SNPs on mouse G6pc1 activity. Using a novel in situ functional assay for glucose-6-phosphatase