RSL genes are sufficient for rhizoid system development in early diverging land plants.

PubMed

Jang, Geupil; Yi, Keke; Pires, Nuno D; Menand, Benoît; Dolan, Liam

2011-06-01

Land plants are anchored to their substratum from which essential inorganic nutrients are taken up. These functions are carried out by a system of rhizoids in early diverging groups of land plants, such as mosses, liverworts and hornworts. Physcomitrella patens RHD SIX-LIKE1 (PpRSL1) and PpRSL2 transcription factors are necessary for rhizoid development in mosses. Similar proteins, AtRHD6 and AtRSL1, control the development of root hairs in Arabidopsis thaliana. Auxin positively regulates root hair development independently of AtRHD6 and AtRSL1 in A. thaliana but the regulatory interactions between auxin and PpRSL1 and PpRSL2 are unknown. We show here that co-expression of PpRSL1 and PpRSL2 is sufficient for the development of the rhizoid system in the moss P. patens; constitutive expression of PpRSL1 and PpRSL2 converts developing leafy shoot axes (gametophores) into rhizoids. During wild-type development, PpRSL1 and PpRSL2 are expressed in the specialized cells that develop rhizoids, indicating that cell-specific expression of PpRSL1 and PpRSL2 is sufficient to promote rhizoid differentiation during wild-type P. patens development. In contrast to A. thaliana, auxin promotes rhizoid development by positively regulating PpRSL1 and PpRSL2 activity in P. patens. This indicates that even though the same genes control the development of root hairs and rhizoids, the regulation of this transcriptional network by auxin is different in these two species. This suggests that auxin might have controlled the development of the first land plant soil anchoring systems that evolved 465 million years ago by regulating the expression of RSL genes and that this regulatory network has changed since mosses and angiosperms last shared a common ancestor.

Hydrophilic TiO2 porous spheres anchored on hydrophobic polypropylene membrane for wettability induced high photodegrading activities.

PubMed

Niu, Fang; Zhang, Le-Sheng; Chen, Chao-Qiu; Li, Wei; Li, Lin; Song, Wei-Guo; Jiang, Lei

2010-08-01

TiO(2) porous nanospheres on polypropylene (PP) films (TiO(2)/PP composite) are produced at ambient temperature. Particle/pore size match up is the key anchoring point to overcome the low affinity between hydrophilic materials and hydrophobic materials. With the hydrophilic TiO(2) catalyst evenly dispersed on a hydrophobic surface, the aqueous solution will selectively skip the substrate and wet the catalysts. Such a wettability-induced smart system maximizes the degrading activity of the TiO(2) catalyst. In photodegrading reactions, the resulting TiO(2)/PP composite film exhibits a 10 times higher activity in flow-type setup than the same TiO(2) catalyst in a traditional batch-type setup.

Interleukin-18 gene deletion protects against sepsis-induced cardiac dysfunction by inhibiting PP2A activity.

PubMed

Okuhara, Yoshitaka; Yokoe, Shunichi; Iwasaku, Toshihiro; Eguchi, Akiyo; Nishimura, Koichi; Li, Wen; Oboshi, Makiko; Naito, Yoshiro; Mano, Toshiaki; Asahi, Michio; Okamura, Haruki; Masuyama, Tohru; Hirotani, Shinichi

2017-09-15

Interleukin-18 (IL-18) neutralization protects against lipopolysaccharide (LPS)-induced injuries, including myocardial dysfunction. However, the mechanism is yet to be fully elucidated. The aim of the present study was to determine whether IL-18 gene deletion prevents sepsis-induced cardiac dysfunction and to elucidate the potential mechanisms underlying IL-18-mediated cardiotoxicity by LPS. Ten-week-old male wild-type (WT) and IL-18 knockout (IL-18 KO) mice were intraperitoneally administered LPS. Serial echocardiography showed better systolic pump function and less left ventricular (LV) dilatation in LPS-treated IL-18 KO mice compared with those in LPS-treated WT mice. LPS treatment significantly decreased the levels of phospholamban (PLN) and Akt phosphorylation in WT mice compared with those in saline-treated WT mice, while the LPS-induced decrease in the phosphorylation levels was attenuated in IL-18 KO mice compared with that in WT mice. IL-18 gene deletion also attenuated an LPS-induced increase of type 2 protein phosphatase 2A (PP2A) activity, a molecule that dephosphorylates PLN and Akt. There was no difference in type 1 protein phosphatase (PP1) activity. To address whether IL-18 affects PLN and Akt phosphorylation via PP2A activation in cardiomyocytes, rat neonatal cardiac myocytes were cultured and stimulated using 100ng/ml of recombinant rat IL-18. Exogenous IL-18 decreased the level of PLN and Akt phosphorylation in cardiomyocytes. PP2A activity but not PP1 activity was increased by IL-18 stimulation in cardiomyocytes. IL-18 plays a pivotal role in advancing sepsis-induced cardiac dysfunction, and the mechanisms underlying IL-18-mediated cardiotoxicity potentially involve the regulation of PLN and Akt phosphorylation through PP2A activity. Copyright © 2017 Elsevier B.V. All rights reserved.

Protein phosphatase 2A: a highly regulated family of serine/threonine phosphatases implicated in cell growth and signalling.

PubMed Central

Janssens, V; Goris, J

2001-01-01

Protein phosphatase 2A (PP2A) comprises a family of serine/threonine phosphatases, minimally containing a well conserved catalytic subunit, the activity of which is highly regulated. Regulation is accomplished mainly by members of a family of regulatory subunits, which determine the substrate specificity, (sub)cellular localization and catalytic activity of the PP2A holoenzymes. Moreover, the catalytic subunit is subject to two types of post-translational modification, phosphorylation and methylation, which are also thought to be important regulatory devices. The regulatory ability of PTPA (PTPase activator), originally identified as a protein stimulating the phosphotyrosine phosphatase activity of PP2A, will also be discussed, alongside the other regulatory inputs. The use of specific PP2A inhibitors and molecular genetics in yeast, Drosophila and mice has revealed roles for PP2A in cell cycle regulation, cell morphology and development. PP2A also plays a prominent role in the regulation of specific signal transduction cascades, as witnessed by its presence in a number of macromolecular signalling modules, where it is often found in association with other phosphatases and kinases. Additionally, PP2A interacts with a substantial number of other cellular and viral proteins, which are PP2A substrates, target PP2A to different subcellular compartments or affect enzyme activity. Finally, the de-regulation of PP2A in some specific pathologies will be touched upon. PMID:11171037

Pulse pressure and diabetes treatments: Blood pressure and pulse pressure difference among glucose lowering modality groups in type 2 diabetes.

PubMed

Alemi, Hamid; Khaloo, Pegah; Mansournia, Mohammad Ali; Rabizadeh, Soghra; Salehi, Salome Sadat; Mirmiranpour, Hossein; Meftah, Neda; Esteghamati, Alireza; Nakhjavani, Manouchehr

2018-02-01

Type 2 diabetes is associated with higher pulse pressure. In this study, we assessed and compared effects of classic diabetes treatments on pulse pressure (PP), systolic blood pressure (SBP), and diastolic blood pressure (DBP) in patients with type 2 diabetes.In a retrospective cohort study, 718 non-hypertensive patients with type 2 diabetes were selected and divided into 4 groups including metformin, insulin, glibenclamide+metformin, and metformin+insulin. They were followed for 4 consecutive visits lasting about 45.5 months. Effects of drug regimens on pulse and blood pressure over time were assessed separately and compared in regression models with generalized estimating equation method and were adjusted for age, duration of diabetes, sex, smoking, and body mass index (BMI).Studied groups had no significant change in PP, SBP, and DBP over time. No significant difference in PP and DBP among studied groups was observed (PP:P = 0.090; DBP:P = 0.063). Pairwise comparisons of PP, SBP, and DBP showed no statistically significant contrast between any 2 studied groups. Interactions of time and treatment were not different among groups.Our results demonstrate patients using metformin got higher PP and SBP over time. Averagely, pulse and blood pressure among groups were not different. Trends of variation in pulse and blood pressure were not different among studied diabetes treatments.

Genome-wide characterization of vibrio phage ϕpp2 with unique arrangements of the mob-like genes

PubMed Central

2012-01-01

Background Vibrio parahaemolyticus is associated with gastroenteritis, wound infections, and septicemia in human and animals. Phages can control the population of the pathogen. So far, the only one reported genome among giant vibriophages is KVP40: 244,835 bp with 26% coding regions that have T4 homologs. Putative homing endonucleases (HE) were found in Vibrio phage KVP40 bearing one segD and Vibrio cholerae phage ICP1 carrying one mobC/E and one segG. Results A newly isolated Vibrio phage ϕpp2, which was specific to the hosts of V. parahaemolyticus and V. alginolyticus, featured a long nonenveloped head of ~90 × 150 nm and tail of ~110 nm. The phage can survive at 50°C for more than one hour. The genome of the phage ϕpp2 was sequenced to be 246,421 bp, which is 1587 bp larger than KVP40. 383 protein-encoding genes (PEGs) and 30 tRNAs were found in the phage ϕpp2. Between the genomes of ϕpp2 and KVP40, 254 genes including 29 PEGs for viral structure were of high similarity, whereas 17 PEGs of KVP40 and 21 PEGs of ϕpp2 were unmatched. In both genomes, the capsid and tail genes have been identified, as well as the extensive representation of the DNA replication, recombination, and repair enzymes. In addition to the three giant indels of 1098, 1143 and 3330 nt, ϕpp2 possessed unique proteins involved in potassium channel, gp2 (DNA end protector), tRNA nucleotidyltransferase, and mob-type HEs, which were not reported in KVP40. The ϕpp2 PEG274, with strong promoters and translational initiation, was identified to be a mobE type, flanked by NrdA and NrdB/C homologs. Coincidently, several pairs of HE-flanking homologs with empty center were found in the phages of Vibrio phages ϕpp2 and KVP40, as well as in Aeromonas phages (Aeh1 and Ae65), and cyanophage P-SSM2. Conclusions Vibrio phage ϕpp2 was characterized by morphology, growth, and genomics with three giant indels and different types of HEs. The gene analysis on the required elements for transcription and translation suggested that the ϕpp2 PEG274 was an active mobE gene. The phage was signified to be a new species of T4-related, differing from KVP40. PMID:22676552

Identification of Plasmodium falciparum Translation Initiation eIF2β Subunit: Direct Interaction with Protein Phosphatase Type 1.

PubMed

Tellier, Géraldine; Lenne, Astrid; Cailliau-Maggio, Katia; Cabezas-Cruz, Alejandro; Valdés, James J; Martoriati, Alain; Aliouat, El M; Gosset, Pierre; Delaire, Baptiste; Fréville, Aline; Pierrot, Christine; Khalife, Jamal

2016-01-01

Protein phosphatase 1 (PP1c) is one of the main phosphatases whose function is shaped by many regulators to confer a specific location and a selective function for this enzyme. Here, we report that eukaryotic initiation factor 2β of Plasmodium falciparum (PfeIF2β) is an interactor of PfPP1c. Sequence analysis of PfeIF2β revealed a deletion of 111 amino acids when compared to its human counterpart and the presence of two potential binding motifs to PfPP1 ((29)FGEKKK(34), (103)KVAW(106)). As expected, we showed that PfeIF2β binds PfeIF2γ and PfeIF5, confirming its canonical interaction with partners of the translation complex. Studies of the PfeIF2β-PfPP1 interaction using wild-type, single and double mutated versions of PfeIF2β revealed that both binding motifs are critical. We next showed that PfeIF2β is able to induce Germinal Vesicle Break Down (GVBD) when expressed in Xenopus oocytes, an indicator of its capacity to regulate PP1. Only combined mutations of both binding motifs abolished the interaction with PP1 and the induction of GVBD. In P. falciparum, although the locus is accessible for genetic manipulation, PfeIF2β seems to play an essential role in intraerythrocytic cycle as no viable knockout parasites were detectable. Interestingly, as for PfPP1, the subcellular fractionation of P. falciparum localized PfeIF2β in cytoplasm and nuclear extracts, suggesting a potential effect on PfPP1 in both compartments and raising the question of a non-canonical function of PfeIf2β in the nucleus. Hence, the role played by PfeIF2β in blood stage parasites could occur at multiple levels involving the binding to proteins of the translational complex and to PfPP1.

Threshold value of home pulse pressure predicting arterial stiffness in patients with type 2 diabetes: KAMOGAWA-HBP study.

PubMed

Kitagawa, Noriyuki; Ushigome, Emi; Matsumoto, Shinobu; Oyabu, Chikako; Ushigome, Hidetaka; Yokota, Isao; Asano, Mai; Tanaka, Muhei; Yamazaki, Masahiro; Fukui, Michiaki

2018-03-01

This cross-sectional multicenter study was designed to evaluate the threshold value of home pulse pressure (PP) and home systolic blood pressure (SBP) predicting the arterial stiffness in 876 patients with type 2 diabetes. We measured the area under the receiver-operating characteristic curve (AUC) and estimated the ability of home PP to identify arterial stiffness using Youden-Index defined cut-off point. The arterial stiffness was measured using the brachial-ankle pulse wave velocity (baPWV). AUC for arterial stiffness in morning PP was significantly greater than that in morning SBP (P < .001). AUC for arterial stiffness in evening PP was also significantly greater than that in evening SBP (P < .001). The optimal cut-off points for morning PP and evening PP, which predicted arterial stiffness, were 54.6 and 56.9 mm Hg, respectively. Our findings indicate that we should pay more attention to increased home PP in patients with type 2 diabetes. ©2018 Wiley Periodicals, Inc.

The B55α Regulatory Subunit of Protein Phosphatase 2A Mediates Fibroblast Growth Factor-Induced p107 Dephosphorylation and Growth Arrest in Chondrocytes

PubMed Central

Daempfling, Lea

2013-01-01

Fibroblast growth factor (FGF)-induced growth arrest of chondrocytes is a unique cell type-specific response which contrasts with the proliferative response of most cell types and underlies several genetic skeletal disorders caused by activating FGF receptor (FGFR) mutations. We have shown that one of the earliest key events in FGF-induced growth arrest is dephosphorylation of the retinoblastoma protein (Rb) family member p107 by protein phosphatase 2A (PP2A), a ubiquitously expressed multisubunit phosphatase. In this report, we show that the PP2A-B55α holoenzyme (PP2A containing the B55α subunit) is responsible for this phenomenon. Only the B55α (55-kDa regulatory subunit, alpha isoform) regulatory subunit of PP2A was able to bind p107, and this interaction was induced by FGF in chondrocytes but not in other cell types. Small interfering RNA (siRNA)-mediated knockdown of B55α prevented p107 dephosphorylation and FGF-induced growth arrest of RCS (rat chondrosarcoma) chondrocytes. Importantly, the B55α subunit bound with higher affinity to dephosphorylated p107. Since the p107 region interacting with B55α is also the site of cyclin-dependent kinase (CDK) binding, B55α association may also prevent p107 phosphorylation by CDKs. FGF treatment induces dephosphorylation of the B55α subunit itself on several serine residues that drastically increases the affinity of B55α for the PP2A A/C dimer and p107. Together these observations suggest a novel mechanism of p107 dephosphorylation mediated by activation of PP2A through B55α dephosphorylation. This mechanism might be a general signal transduction pathway used by PP2A to initiate cell cycle arrest when required by external signals. PMID:23716589

Protein Phosphatase-1 Inhibitor-2 Is a Novel Memory Suppressor.

PubMed

Yang, Hongtian; Hou, Hailong; Pahng, Amanda; Gu, Hua; Nairn, Angus C; Tang, Ya-Ping; Colombo, Paul J; Xia, Houhui

2015-11-11

Reversible phosphorylation, a fundamental regulatory mechanism required for many biological processes including memory formation, is coordinated by the opposing actions of protein kinases and phosphatases. Type I protein phosphatase (PP1), in particular, has been shown to constrain learning and memory formation. However, how PP1 might be regulated in memory is still not clear. Our previous work has elucidated that PP1 inhibitor-2 (I-2) is an endogenous regulator of PP1 in hippocampal and cortical neurons (Hou et al., 2013). Contrary to expectation, our studies of contextual fear conditioning and novel object recognition in I-2 heterozygous mice suggest that I-2 is a memory suppressor. In addition, lentiviral knock-down of I-2 in the rat dorsal hippocampus facilitated memory for tasks dependent on the hippocampus. Our data indicate that I-2 suppresses memory formation, probably via negatively regulating the phosphorylation of cAMP/calcium response element-binding protein (CREB) at serine 133 and CREB-mediated gene expression in dorsal hippocampus. Surprisingly, the data from both biochemical and behavioral studies suggest that I-2, despite its assumed action as a PP1 inhibitor, is a positive regulator of PP1 function in memory formation. We found that inhibitor-2 acts as a memory suppressor through its positive functional influence on type I protein phosphatase (PP1), likely resulting in negative regulation of cAMP/calcium response element-binding protein (CREB) and CREB-activated gene expression. Our studies thus provide an interesting example of a molecule with an in vivo function that is opposite to its in vitro function. PP1 plays critical roles in many essential physiological functions such as cell mitosis and glucose metabolism in addition to its known role in memory formation. PP1 pharmacological inhibitors would thus not be able to serve as good therapeutic reagents because of its many targets. However, identification of PP1 inhibitor-2 as a critical contributor to suppression of memory formation by PP1 may provide a novel therapeutic target for memory-related diseases. Copyright © 2015 the authors 0270-6474/15/3515082-06$15.00/0.

New pentacoordinated rhodium species as unexpected products during the in situ generation of dimeric diphosphine-rhodium neutral catalysts.

PubMed

Meissner, Antje; König, Anja; Drexler, Hans-Joachim; Thede, Richard; Baumann, Wolfgang; Heller, Detlef

2014-11-03

Dimeric rhodium complexes of the type [Rh(PP)(μ2 -Cl)]2 (PP=diphosphine) are often used as precatalysts and are generated "in situ" from the corresponding diolefin complexes by exchange of the diene with the desired diphosphine. Herein, we report that the "in situ" procedure also leads to unexpected monomeric pentacoordinated neutral complexes of the type [RhCl(PP)(diolefin)], for the first time herein characterized by NMR spectroscopy and X-ray crystallography for the ligands 1,4-bis(diphenylphosphino)propane (DPPP), 1,4-bis(diphenylphosphino)butane (DPPB), and 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP). The pentacoordinated complexes are in equilibrium with the dimeric target compound [Rh(PP)(μ2 -Cl)]2 . The equilibrium is influenced by the rhodium-diolefin precursor, the solvent and the temperature. Based on the results of NMR and UV/Vis spectroscopic analysis (kinetics) it could be shown that the pentacoordinated complex [RhCl(PP)(diolefin)] may arise both from the "in situ"-generated neutral complex [Rh(PP)(μ2 -Cl)] by reaction with the free diolefin and, more surprisingly, directly from [Rh(diolefin)(μ2 -Cl)]2 and the diphosphine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Human cytomegalovirus carries serine/threonine protein phosphatases PP1 and a host-cell derived PP2A.

PubMed Central

Michelson, S; Turowski, P; Picard, L; Goris, J; Landini, M P; Topilko, A; Hemmings, B; Bessia, C; Garcia, A; Virelizier, J L

1996-01-01

Human cytomegalovirus (CMV), a herpesvirus, is an important cause of morbidity and mortality in immunocompromised patients. When studying hyper-immediate-early events after contact between CMV virions and the cell membrane, we observed a hypophosphorylation of cellular proteins within 10 min. This can be explained in part by our finding that purified CMV contains serine/threonine protein phosphatase activities. Biochemical analyses indicate that this protein phosphatase activity has all characteristics of type 1 and 2A protein phosphatases (PP1 and PP2A). Specifically, PP1 accounts for approximately 30% and PP2A accounts for the remaining 70% of the phosphorylase phosphatase activity found. CMV produced in astrocytoma cells stably expressing an amino-terminally tagged PP2A catalytic subunit contained tagged enzyme, thus demonstrating the cellular origin of CMV-associated PP2A. PP2A is specifically found inside the virus, associated with the nucleocapsid fraction. Western blot (immunoblot) analysis of purified virus revealed the presence of the catalytic subunits of PP2A and PP1. Furthermore, the catalytic subunit of PP2A appears to be complexed to the regulatory subunits PR65 and PR55, which is also the most abundant configuration of this enzyme found in the host cells. Incubation of virus with okadaic acid before contact of CMV with cells prevented hypophosphorylation of cellular proteins, thus demonstrating the role of CMV-associated phosphatases in this phenomenon. CMV can thus transport an active enzyme from one cell to another. PMID:8627658

Pharmacological Activation of Protein Phosphatase 2 A (PP2A): A Novel Strategy to Fight Against Human Malignancies?

PubMed

Carratù, Maria Rosaria; Signorile, Anna; De Rasmo, Domenico; Reale, Antonia; Vacca, Angelo

2016-01-01

The serine-threonine protein phosphatase 2A (PP2A) regulates multiple cell signaling cascades and its inactivation by viral oncoproteins, mutation of specific structural subunits or upregulation of the cellular endogenous inhibitors may contribute to malignant transformation by regulating specific phosphorylation events. Pharmacological modulation of PP2A activity is becoming an attractive strategy for cancer treatment. Some compounds targeting PP2A are able to induce PP2A reactivation and subsequent cell death in several types of cancer. We undertook a search of bibliographic databases for peer-reviewed articles focusing on the main item of the review. We selected articles published in indexed journals. The quality of retrieved papers was appraised using the standard bibliometric indicators. One hundred and fourteen papers were included in the review. Twenty-seven papers gave an overview of structure and physiological role of PP2A. Twenty-five papers outlined the role of PP2A in tumor suppression. Forty papers analyzed the mechanism involved in PP2A reactivation by synthetic compounds, and twenty-two papers outlined the capability of natural compounds of restoring PP2A activity and how this could be beneficial. Findings analyzed in this review underline the central role of PP2A as a regulator of cell growth and survival, hence its function as tumor suppressor. The discovery that some compounds, either synthetic or natural, are capable of reactivating PP2A opens up new perspectives for future strategies to fully exploit therapeutic potential in human cancer. Thus, this review could also be of particular interest to pharmaceutical or biotechnology companies for drug design and targeted delivery.

Antihelminthic drug niclosamide inhibits CIP2A and reactivates tumor suppressor protein phosphatase 2A in non-small cell lung cancer cells.

PubMed

Kim, Myeong-Ok; Choe, Min Ho; Yoon, Yi Na; Ahn, Jiyeon; Yoo, Minjin; Jung, Kwan-Young; An, Sungkwan; Hwang, Sang-Gu; Oh, Jeong Su; Kim, Jae-Sung

2017-11-15

Protein phosphatase 2A (PP2A) is a critical tumor suppressor complex responsible for the inactivation of various oncogenes. Recently, PP2A reactivation has emerged asan anticancer strategy. Cancerous inhibitor of protein phosphatase 2A (CIP2A), an endogenous inhibitor of PP2A, is upregulated in many cancer cells, including non-small cell lung cancer (NSCLC) cells. We demonstrated that the antihelminthic drug niclosamide inhibited the expression of CIP2A and reactivated the tumor suppressor PP2A in NSCLC cells. We performed a drug-repurposing screen and identified niclosamide asa CIP2A suppressor in NSCLC cells. Niclosamide inhibited cell proliferation, colony formation, and tumor sphere formation, and induced mitochondrial dysfunction through increased mitochondrial ROS production in NSCLC cells; however, these effects were rescued by CIP2A overexpression, which indicated that the antitumor activity of niclosamide was dependent on CIP2A. We found that niclosamide increased PP2A activity through CIP2A inhibition, which reduced the phosphorylation of several oncogenic proteins. Moreover, we found that a niclosamide analog inhibited CIP2A expression and increased PP2A activity in several types of NSCLC cells. Finally, we showed that other well-known PP2A activators, including forskolin and FTY720, did not inhibit CIP2A and that their activities were not dependent on CIP2A. Collectively, our data suggested that niclosamide effectively suppressed CIP2A expression and subsequently activated PP2A in NSCLC cells. This provided strong evidence for the potential use of niclosamide asa PP2A-activating drug in the clinical treatment of NSCLC. Copyright © 2017 Elsevier Inc. All rights reserved.

MCLR-induced PP2A inhibition and subsequent Rac1 inactivation and hyperphosphorylation of cytoskeleton-associated proteins are involved in cytoskeleton rearrangement in SMMC-7721 human liver cancer cell line.

PubMed

Wang, Hao; Liu, Jinghui; Lin, Shuyan; Wang, Beilei; Xing, Mingluan; Guo, Zonglou; Xu, Lihong

2014-10-01

Cyanobacteria-derived toxin microcystin-LR (MCLR) has been widely investigated in its effects on normal cells, there is little information concerning its effects on cancer cells. In the present study, the SMMC-7721 human liver cancer cell line treated with MCLR was used to investigate the change of PP2A, cytoskeleton rearrangement, phosphorylation levels of PP2A substrates that related with cytoskeleton stability and explored underlying mechanisms. Here, we confirmed that MCLR entered into SMMC-7721 cells, bound to PP2A/C subunit and inhibited the activity of PP2A. The upregulation of phosphorylation of the PP2A/C subunit and PP2A regulation protein α4, as well as the change in the association of PP2A/C with α4, were responsible for the decrease in PP2A activity. Another novel finding is that the rearrangement of filamentous actin and microtubules led by MCLR may attribute to the increased phosphorylation of HSP27, VASP and cofilin due to PP2A inhibition. As a result of weakened interactions with PP2A and alterations in its subcellular localization, Rac1 may contribute to the cytoskeletal rearrangement induced by MCLR in SMMC-7721 cells. The current paper presents the first report demonstrating the characteristic of PP2A in MCLR exposed cancer cells, which were more susceptible to MCLR compared with the normal cell lines we previously found, which may be owing to the absence of some type of compensatory mechanisms. The hyperphosphorylation of cytoskeleton-associated proteins and Rac1 inactivation which were induced by inhibition of PP2A are shown to be involved in cytoskeleton rearrangement. Copyright © 2014 Elsevier Ltd. All rights reserved.

Overexpression of a Protein Phosphatase 2C from Beech Seeds in Arabidopsis Shows Phenotypes Related to Abscisic Acid Responses and Gibberellin Biosynthesis1

PubMed Central

Reyes, David; Rodríguez, Dolores; González-García, Mary Paz; Lorenzo, Oscar; Nicolás, Gregorio; García-Martínez, José Luis; Nicolás, Carlos

2006-01-01

A functional abscisic acid (ABA)-induced protein phosphatase type 2C (PP2C) was previously isolated from beech (Fagus sylvatica) seeds (FsPP2C2). Because transgenic work is not possible in beech, in this study we overexpressed this gene in Arabidopsis (Arabidopsis thaliana) to provide genetic evidence on FsPP2C2 function in seed dormancy and other plant responses. In contrast with other PP2Cs described so far, constitutive expression of FsPP2C2 in Arabidopsis, under the cauliflower mosaic virus 35S promoter, produced enhanced sensitivity to ABA and abiotic stress in seeds and vegetative tissues, dwarf phenotype, and delayed flowering, and all these effects were reversed by gibberellic acid application. The levels of active gibberellins (GAs) were reduced in 35S:FsPP2C2 plants, although transcript levels of AtGA20ox1 and AtGA3ox1 increased, probably as a result of negative feedback regulation, whereas the expression of GASA1 was induced by GAs. Additionally, FsPP2C2-overexpressing plants showed a strong induction of the Responsive to ABA 18 (RAB18) gene. Interestingly, FsPP2C2 contains two nuclear targeting sequences, and transient expression assays revealed that ABA directed this protein to the nucleus. Whereas other plant PP2Cs have been shown to act as negative regulators, our results support the hypothesis that FsPP2C2 is a positive regulator of ABA. Moreover, our results indicate the existence of potential cross-talk between ABA signaling and GA biosynthesis. PMID:16815952

Antagonistic activities of the immunomodulator and PP2A-activating drug FTY720 (Fingolimod, Gilenya) in Jak2-driven hematologic malignancies

PubMed Central

Oaks, Joshua J.; Santhanam, Ramasamy; Walker, Christopher J.; Roof, Steve; Harb, Jason G.; Ferenchak, Greg; Eisfeld, Ann-Kathrin; Van Brocklyn, James R.; Briesewitz, Roger; Saddoughi, Sahar A.; Nagata, Kyosuke; Bittman, Robert; Caligiuri, Michael A.; Abdel-Wahab, Omar; Levine, Ross; Arlinghaus, Ralph B.; Quintas-Cardama, Alfonso; Goldman, John M.; Apperley, Jane; Reid, Alistair; Milojkovic, Dragana; Ziolo, Mark T.; Marcucci, Guido; Ogretmen, Besim; Neviani, Paolo

2013-01-01

FTY720 (Fingolimod, Gilenya) is a sphingosine analog used as an immunosuppressant in multiple sclerosis patients. FTY720 is also a potent protein phosphatase 2A (PP2A)–activating drug (PAD). PP2A is a tumor suppressor found inactivated in different types of cancer. We show here that PP2A is inactive in polycythemia vera (PV) and other myeloproliferative neoplasms characterized by the expression of the transforming Jak2V617F oncogene. PP2A inactivation occurs in a Jak2V617F dose/kinase-dependent manner through the PI-3Kγ-PKC–induced phosphorylation of the PP2A inhibitor SET. Genetic or PAD-mediated PP2A reactivation induces Jak2V617F inactivation/downregulation and impairs clonogenic potential of Jak2V617F cell lines and PV but not normal CD34+ progenitors. Likewise, FTY720 decreases leukemic allelic burden, reduces splenomegaly, and significantly increases survival of Jak2V617F leukemic mice without adverse effects. Mechanistically, we show that in Jak2V617F cells, FTY720 antileukemic activity requires neither FTY720 phosphorylation (FTY720-P) nor SET dimerization or ceramide induction but depends on interaction with SET K209. Moreover, we show that Jak2V617F also utilizes an alternative sphingosine kinase-1–mediated pathway to inhibit PP2A and that FTY720-P, acting as a sphingosine-1-phosphate-receptor-1 agonist, elicits signals leading to the Jak2-PI-3Kγ-PKC-SET–mediated PP2A inhibition. Thus, PADs (eg, FTY720) represent suitable therapeutic alternatives for Jak2V617F MPNs. PMID:23926298

Increased AβPP Processing in Familial Danish Dementia Patients

PubMed Central

Matsuda, Shuji; Tamayev, Robert; D’Adamio, Luciano

2013-01-01

An autosomal dominant mutation in the BRI2/ITM2B gene causes Familial Danish Dementia (FDD). We have generated a mouse model of FDD, called FDDKI, genetically congruous to the human disease. These mice carry one mutant and one wild type Bri2/Itm2b allele, like FDD patients. Analysis of FDDKI mice and samples from human patients has shown that the Danish mutation causes loss of Bri2 protein. FDDKI mice show synaptic plasticity and memory impairments. BRI2 is a physiological interactor of amyloid-β protein precursor (AβPP), a gene associated with Alzheimer’s disease, which inhibits processing of AβPP. AβPP/Bri2 complexes are reduced in synaptic membranes of FDDKI mice. Consequently, AβPP metabolites derived from processing of AβPP by β-, α-, and γ-secretases are increased in Danish dementia mice. AβPP haplodeficiency prevents memory and synaptic dysfunctions, consistent with a role for AβPP-metabolites in the pathogenesis of memory and synaptic deficits. This genetic suppression provides compelling evidence that AβPP and BRI2 functionally interact. Here, we have investigated whether AβPP processing is altered in FDD patients’ brain samples. We find that the levels of several AβPP metabolites, including Aβ, are significantly increased in the brain sample derived from an FDD patient. Our data are consistent with the findings in FDDKI mice, and support the hypothesis that the neurological effects of the Danish form of BRI2 are caused by toxic AβPP metabolites, suggesting that Familial Danish and Alzheimer’s dementias share common pathogenic mechanisms. PMID:21841249

Increased AβPP processing in familial Danish dementia patients.

PubMed

Matsuda, Shuji; Tamayev, Robert; D'Adamio, Luciano

2011-01-01

An autosomal dominant mutation in the BRI2/ITM2B gene causes Familial Danish Dementia (FDD). We have generated a mouse model of FDD, called FDDKI, genetically congruous to the human disease. These mice carry one mutant and one wild type Bri2/Itm2b allele, like FDD patients. Analysis of FDDKI mice and samples from human patients has shown that the Danish mutation causes loss of Bri2 protein. FDDKI mice show synaptic plasticity and memory impairments. BRI2 is a physiological interactor of amyloid-β protein precursor (AβPP), a gene associated with Alzheimer's disease, which inhibits processing of AβPP. AβPP/Bri2 complexes are reduced in synaptic membranes of FDDKI mice. Consequently, AβPP metabolites derived from processing of AβPP by β-, α-, and γ-secretases are increased in Danish dementia mice. AβPP haplodeficiency prevents memory and synaptic dysfunctions, consistent with a role for AβPP-metabolites in the pathogenesis of memory and synaptic deficits. This genetic suppression provides compelling evidence that AβPP and BRI2 functionally interact. Here, we have investigated whether AβPP processing is altered in FDD patients' brain samples. We find that the levels of several AβPP metabolites, including Aβ, are significantly increased in the brain sample derived from an FDD patient. Our data are consistent with the findings in FDDKI mice, and support the hypothesis that the neurological effects of the Danish form of BRI2 are caused by toxic AβPP metabolites, suggesting that Familial Danish and Alzheimer's dementias share common pathogenic mechanisms.

A New Protein Phosphatase 2C (FsPP2C1) Induced by Abscisic Acid Is Specifically Expressed in Dormant Beechnut Seeds1

PubMed Central

Lorenzo, Oscar; Rodríguez, Dolores; Nicolás, Gregorio; Rodríguez, Pedro L.; Nicolás, Carlos

2001-01-01

An abscisic acid (ABA)-induced cDNA fragment encoding a putative protein phosphatase 2C (PP2C) was obtained by means of differential reverse transcriptase-polymerase chain reaction approach. The full-length clone was isolated from a cDNA library constructed using mRNA from ABA-treated beechnut (Fagus sylvatica) seeds. This clone presents all the features of plant type PP2C and exhibits homology to members of this family such as AthPP2CA (61%), ABI1 (48%), or ABI2 (47%), therefore it was named FsPP2C1. The expression of FsPP2C1 is detected in dormant seeds and increases after ABA treatment, when seeds are maintained dormant, but it decreases and tends to disappear when dormancy is being released by stratification or under gibberellic acid treatment. Moreover, drought stress seems to have no effect on FsPP2C1 transcript accumulation. The FsPP2C1 transcript expression is tissue specific and was found to accumulate in ABA-treated seeds rather than in other ABA-treated vegetative tissues examined. These results suggest that the corresponding protein could be related to ABA-induced seed dormancy. By expressing FsPP2C1 in Escherichia coli as a histidine tag fusion protein, we have obtained direct biochemical evidence supporting Mg2+-dependent phosphatase activity of this protein. PMID:11299374

Two ω-3 FADs Are Associated with Peach Fruit Volatile Formation

PubMed Central

Wang, Jiao-Jiao; Liu, Hong-Ru; Gao, Jie; Huang, Yu-Ji; Zhang, Bo; Chen, Kun-Song

2016-01-01

Aroma-related volatiles, together with sugars and acids, play an important role in determining fruit flavor quality. Characteristic volatiles of peach fruit are mainly derived from fatty acids such as linoleic acid (18:2) and linolenic acid (18:3). In the present study, six genes encoding fatty acid desaturases (FAD) were cloned, including two ω-6 FAD genes (PpFAD2, PpFAD6) and four ω-3 FAD genes (PpFAD3-1, PpFAD3-2, PpFAD7 and PpFAD8). Heterologous expression of peach FADs in tobacco plants showed that PpFAD3-1, and PpFAD3-2 significantly reduced contents of 18:2, and accumulated significant higher levels of 18:3. In the case of volatiles, transgenic plants produced lower concentrations of hexanal and higher levels of (E)-2-hexenal. Consequently, the ratio of the (E)-2-hexenal and hexanal was about 5- and 3-fold higher than that of wild type (WT) in PpFAD3-1 and PpFAD3-2 transformants, respectively. No significant changes in volatile profiles were observed in transgenic plants overexpressing the four other peach FAD genes. Real-time quantitative polymerase chain reaction (qPCR) analysis showed that ripe fruit had high PpFAD3-1 and low PpFAD3-2 transcript levels. In contrast, high PpFAD3-2 and low PpFAD3-1 transcript levels were observed in young fruit. These results indicate a temporal regulation of these two ω-3 FADs during development and ripening, influencing peach fruit volatile formation. PMID:27043529

Small G proteins Rac1 and Ras regulate serine/threonine protein phosphatase 5 (PP5)·extracellular signal-regulated kinase (ERK) complexes involved in the feedback regulation of Raf1.

PubMed

Mazalouskas, Matthew D; Godoy-Ruiz, Raquel; Weber, David J; Zimmer, Danna B; Honkanen, Richard E; Wadzinski, Brian E

2014-02-14

Serine/threonine protein phosphatase 5 (PP5, PPP5C) is known to interact with the chaperonin heat shock protein 90 (HSP90) and is involved in the regulation of multiple cellular signaling cascades that control diverse cellular processes, such as cell growth, differentiation, proliferation, motility, and apoptosis. Here, we identify PP5 in stable complexes with extracellular signal-regulated kinases (ERKs). Studies using mutant proteins reveal that the formation of PP5·ERK1 and PP5·ERK2 complexes partially depends on HSP90 binding to PP5 but does not require PP5 or ERK1/2 activity. However, PP5 and ERK activity regulates the phosphorylation state of Raf1 kinase, an upstream activator of ERK signaling. Whereas expression of constitutively active Rac1 promotes the assembly of PP5·ERK1/2 complexes, acute activation of ERK1/2 fails to influence the phosphatase-kinase interaction. Introduction of oncogenic HRas (HRas(V12)) has no effect on PP5-ERK1 binding but selectively decreases the interaction of PP5 with ERK2, in a manner that is independent of PP5 and MAPK/ERK kinase (MEK) activity, yet paradoxically requires ERK2 activity. Additional studies conducted with oncogenic variants of KRas4B reveal that KRas(L61), but not KRas(V12), also decreases the PP5-ERK2 interaction. The expression of wild type HRas or KRas proteins fails to reduce PP5-ERK2 binding, indicating that the effect is specific to HRas(V12) and KRas(L61) gain-of-function mutations. These findings reveal a novel, differential responsiveness of PP5-ERK1 and PP5-ERK2 interactions to select oncogenic Ras variants and also support a role for PP5·ERK complexes in regulating the feedback phosphorylation of PP5-associated Raf1.

The performance and long-term stability of low-cost separators in single-chamber bottle-type microbial fuel cells.

PubMed

Kondaveeti, Sanath; Kakarla, Ramesh; Kim, Hong Suck; Kim, Byung-Goon; Min, Booki

2018-02-01

This study evaluates long-term stability of low-cost separators in single-chamber bottle-type microbial fuel cells with domestic wastewater. Low-cost separators tested in this study were nonwoven fabrics (NWF) of polypropylene (PP80, PP100), textile fabrics of polyphenylene sulfide (PPS), sulfonated polyphenylene sulfide (SPPS), and cellulose esters. NWF PP80 separator generated the highest power density of 280 mW/m 2 , which was higher than with ion-exchange membranes (cation exchange membrane; CEM = 271 mW/m 2 , cation exchange membrane; CMI = 196 mW/m 2 , Nafion = 260 mW/m 2 ). MFC operations with other size-selective separators such as SPPS, PPS, and cellulose esters exhibited power densities of 261, 231, and 250 mW/m 2 , respectively. During a 280-day operation, initial power density of PP80 (278 mW/m 2 ) was decreased to 257 mW/m 2 , but this decrease was smaller than with others (Nafion: 265-230 mW/m 2 ; PP100: 220-126 mW/m 2 ). The anode potential of around -430 mV did not change much with all separators in the long-term operation, but the initial cathode potential gradually decreased. Fouling analysis suggested that the presence of carbonaceous substance on Nafion and PP80 after 280 days of operation and Nafion was subject to be more biofouling.

Protein phosphatase 2ACα gene knock-out results in cortical atrophy through activating hippo cascade in neuronal progenitor cells.

PubMed

Liu, Bo; Sun, Li-Hua; Huang, Yan-Fei; Guo, Li-Jun; Luo, Li-Shu

2018-02-01

Protein phosphatase 2ACα (PP2ACα), a vital member of the protein phosphatase family, has been studied primarily as a regulator for the development, growth and protein synthesis of a lot of cell types. Dysfunction of PP2ACα protein results in neurodegenerative disease; however, this finding has not been directly confirmed in the mouse model with PP2ACα gene knock-out. Therefore, in this study presented here, we generated the PP2ACα gene knock-out mouse model by the Cre-loxP targeting gene system, with the purpose to directly observe the regulatory role of PP2ACα gene in the development of mouse's cerebral cortex. We observe that knocking-out PP2ACα gene in the central nervous system (CNS) results in cortical neuronal shrinkage, synaptic plasticity impairments, and learning/memory deficits. Further study reveals that PP2ACα gene knock-out initiates Hippo cascade in cortical neuroprogenitor cells (NPCs), which blocks YAP translocation into the nuclei of NPCs. Notably, p73, directly targeted by Hippo cascade, can bind to the promoter of glutaminase2 (GLS2) that plays a dominant role in the enzymatic regulation of glutamate/glutamine cycle. Finally, we find that PP2ACα gene knock-out inhibits the glutamine synthesis through up-regulating the activity of phosphorylated-p73 in cortical NPCs. Taken together, it concludes that PP2ACα critically supports cortical neuronal growth and cognitive function via regulating the signaling transduction of Hippo-p73 cascade. And PP2ACα indirectly modulates the glutamine synthesis of cortical NPCs through targeting p73 that plays a direct transcriptional regulatory role in the gene expression of GLS2. Copyright © 2017 Elsevier Ltd. All rights reserved.

Negative Regulation of Abscisic Acid Signaling by the Fagus sylvatica FsPP2C1 Plays A Role in Seed Dormancy Regulation and Promotion of Seed Germination1

PubMed Central

González-García, Mary Paz; Rodríguez, Dolores; Nicolás, Carlos; Rodríguez, Pedro Luis; Nicolás, Gregorio; Lorenzo, Oscar

2003-01-01

FsPP2C1 was previously isolated from beech (Fagus sylvatica) seeds as a functional protein phosphatase type-2C (PP2C) with all the conserved features of these enzymes and high homology to ABI1, ABI2, and PP2CA, PP2Cs identified as negative regulators of ABA signaling. The expression of FsPP2C1 was induced upon abscisic acid (ABA) treatment and was also up-regulated during early weeks of stratification. Furthermore, this gene was specifically expressed in ABA-treated seeds and was hardly detectable in vegetative tissues. In this report, to provide genetic evidence on FsPP2C1 function in seed dormancy and germination, we used an overexpression approach in Arabidopsis because transgenic work is not feasible in beech. Constitutive expression of FsPP2C1 under the cauliflower mosaic virus 35S promoter confers ABA insensitivity in Arabidopsis seeds and, consequently, a reduced degree of seed dormancy. Additionally, transgenic 35S:FsPP2C1 plants are able to germinate under unfavorable conditions, as inhibitory concentrations of mannitol, NaCl, or paclobutrazol. In vegetative tissues, Arabidopsis FsPP2C1 transgenic plants show ABA-resistant early root growth and diminished induction of the ABA-response genes RAB18 and KIN2, but no effect on stomatal closure regulation. Seed and vegetative phenotypes of Arabidopsis 35S:FsPP2C1 plants suggest that FsPP2C1 negatively regulates ABA signaling. The ABA inducibility of FsPP2C1 expression, together with the transcript accumulation mainly in seeds, suggest that it could play an important role modulating ABA signaling in beechnuts through a negative feedback loop. Finally, we suggest that negative regulation of ABA signaling by FsPP2C1 is a factor contributing to promote the transition from seed dormancy to germination during early weeks of stratification. PMID:12970481

Positive Psychological Interventions for Patients with Type 2 Diabetes: Rationale, Theoretical Model, and Intervention Development

PubMed Central

Huffman, Jeff C.; DuBois, Christina M.; Millstein, Rachel A.; Celano, Christopher M.; Wexler, Deborah

2015-01-01

Most patients with type 2 diabetes (T2D) have suboptimal adherence to recommended diet, physical activity, and/or medication. Current approaches to improve health behaviors in T2D have been variably effective, and successful interventions are often complex and intensive. It is therefore vital to develop interventions that are simple, well-accepted, and applicable to a wide range of patients who suffer from T2D. One approach may be to boost positive psychological states, such as positive affect or optimism, as these constructs have been prospectively and independently linked to improvements in health behaviors. Positive psychology (PP) interventions, which utilize systematic exercises to increase optimism, well-being, and positive affect, consistently increase positive states and are easily delivered to patients with chronic illnesses. However, to our knowledge, PP interventions have not been formally tested in T2D. In this paper, we review a theoretical model for the use of PP interventions to target health behaviors in T2D, describe the structure and content of a PP intervention for T2D patients, and describe baseline data from a single-arm proof-of-concept (N = 15) intervention study in T2D patients with or without depression. We also discuss how PP interventions could be combined with motivational interviewing (MI) interventions to provide a blended psychological-behavioral approach. PMID:26064980

Factors affecting the frequency of infection by the sigma virus in experimental populations of Drosophila melanogaster.

PubMed

Fleuriet, A

1982-01-01

The experiments reported in this paper deal with the maintenance of the non contagious, hereditary virus sigma in populations of its host, Drosophila melanogaster. Evidence was previously provided of the existence of two viral Types I and II, depending on their sensitivity to the ref(2)Pp allele (the ref(2)P locus interferes with the multiplication of the virus in the fly). The viral Type I which is the most sensitive to the ref(2)Pp allele, is eliminated in the presence of this allele, even when most of the flies were originally infected in the population. On the contrary, the presence of the ref(2)Pp allele does not prevent a viral Type II, introduced in a population, from infecting most of the flies. The possibility that a change has occurred recently in French natural populations of Drosophila melanogaster is discussed.

SCF E3 ligase PP2-B11 plays a positive role in response to salt stress in Arabidopsis

PubMed Central

Jia, Fengjuan; Wang, Chunyan; Huang, Jinguang; Yang, Guodong; Wu, Changai; Zheng, Chengchao

2015-01-01

Skp1–Cullin–F-box (SCF) E3 ligases are essential to the post-translational regulation of many important factors involved in cellular signal transduction. In this study, we identified an F-box protein from Arabidopsis thaliana, AtPP2-B11, which was remarkably induced with increased duration of salt treatment in terms of both transcript and protein levels. Transgenic Arabidopsis plants overexpressing AtPP2-B11 exhibited obvious tolerance to high salinity, whereas the RNA interference line was more sensitive to salt stress than wild-type plants. Isobaric tag for relative and absolute quantification analysis revealed that 4311 differentially expressed proteins were regulated by AtPP2-B11 under salt stress. AtPP2-B11 could upregulate the expression of annexin1 (AnnAt1) and function as a molecular link between salt stress and reactive oxygen species accumulation in Arabidopsis. Moreover, AtPP2-B11 influenced the expression of Na+ homeostasis genes under salt stress, and the AtPP2-B11 overexpressing lines exhibited lower Na+ accumulation. These results suggest that AtPP2-B11 functions as a positive regulator in response to salt stress in Arabidopsis. PMID:26041321

Identification and Characterization of an Alternatively Spliced Isoform of the Human Protein Phosphatase 2Aα Catalytic Subunit*

PubMed Central

Migueleti, Deivid L. S.; Smetana, Juliana H. C.; Nunes, Hugo F.; Kobarg, Jörg; Zanchin, Nilson I. T.

2012-01-01

PP2A is the main serine/threonine-specific phosphatase in animal cells. The active phosphatase has been described as a holoenzyme consisting of a catalytic, a scaffolding, and a variable regulatory subunit, all encoded by multiple genes, allowing for the assembly of more than 70 different holoenzymes. The catalytic subunit can also interact with α4, TIPRL (TIP41, TOR signaling pathway regulator-like), the methyl-transferase LCMT-1, and the methyl-esterase PME-1. Here, we report that the gene encoding the catalytic subunit PP2Acα can generate two mRNA types, the standard mRNA and a shorter isoform, lacking exon 5, which we termed PP2Acα2. Higher levels of the PP2Acα2 mRNA, equivalent to the level of the longer PP2Acα mRNA, were detected in peripheral blood mononuclear cells that were left to rest for 24 h. After this time, the peripheral blood mononuclear cells are still viable and the PP2Acα2 mRNA decreases soon after they are transferred to culture medium, showing that generation of the shorter isoform depends on the incubation conditions. FLAG-tagged PP2Acα2 expressed in HEK293 is catalytically inactive. It displays a specific interaction profile with enhanced binding to the α4 regulatory subunit, but no binding to the scaffolding subunit and PME-1. Consistently, α4 out-competes PME-1 and LCMT-1 for binding to both PP2Acα isoforms in pulldown assays. Together with molecular modeling studies, this suggests that all three regulators share a common binding surface on the catalytic subunit. Our findings add important new insights into the complex mechanisms of PP2A regulation. PMID:22167190

Synemin promotes AKT-dependent glioblastoma cell proliferation by antagonizing PP2A.

PubMed

Pitre, Aaron; Davis, Nathan; Paul, Madhumita; Orr, A Wayne; Skalli, Omar

2012-04-01

The intermediate filament protein synemin is present in astrocyte progenitors and glioblastoma cells but not in mature astrocytes. Here we demonstrate a role for synemin in enhancing glioblastoma cell proliferation and clonogenic survival, as synemin RNA interference decreased both behaviors by inducing G1 arrest along with Rb hypophosphorylation and increased protein levels of the G1/S inhibitors p21(Cip1) and p27(Kip1). Akt involvement was demonstrated by decreased phosphorylation of its substrate, p21(Cip1), and reduced Akt catalytic activity and phosphorylation at essential activation sites. Synemin silencing, however, did not affect the activities of PDPK1 and mTOR complex 2, which directly phosphorylate Akt activation sites, but instead enhanced the activity of the major regulator of Akt dephosphorylation, protein phosphatase type 2A (PP2A). This was accompanied by changes in PP2A subcellular distribution resulting in increased physical interactions between PP2A and Akt, as shown by proximity ligation assays (PLAs). PLAs and immunoprecipitation experiments further revealed that synemin and PP2A form a protein complex. In addition, treatment of synemin-silenced cells with the PP2A inhibitor cantharidic acid resulted in proliferation and pAkt and pRb levels similar to those of controls. Collectively these results indicate that synemin positively regulates glioblastoma cell proliferation by helping sequester PP2A away from Akt, thereby favoring Akt activation.

Transcriptional regulation of SlPYL, SlPP2C, and SlSnRK2 gene families encoding ABA signal core components during tomato fruit development and drought stress.

PubMed

Sun, Liang; Wang, Yan-Ping; Chen, Pei; Ren, Jie; Ji, Kai; Li, Qian; Li, Ping; Dai, Sheng-Jie; Leng, Ping

2011-11-01

In order to characterize the potential transcriptional regulation of core components of abscisic acid (ABA) signal transduction in tomato fruit development and drought stress, eight SlPYL (ABA receptor), seven SlPP2C (type 2C protein phosphatase), and eight SlSnRK2 (subfamily 2 of SNF1-related kinases) full-length cDNA sequences were isolated from the tomato nucleotide database of NCBI GenBank. All SlPYL, SlPP2C, and SlSnRK2 genes obtained are homologous to Arabidopsis AtPYL, AtPP2C, and AtSnRK2 genes, respectively. Based on phylogenetic analysis, SlPYLs and SlSnRK2s were clustered into three subfamilies/subclasses, and all SlPP2Cs belonged to PP2C group A. Within the SlPYL gene family, SlPYL1, SlPYL2, SlPYL3, and SlPYL6 were the major genes involved in the regulation of fruit development. Among them, SlPYL1 and SlPYL2 were expressed at high levels throughout the process of fruit development and ripening; SlPYL3 was strongly expressed at the immature green (IM) and mature green (MG) stages, while SlPYL6 was expressed strongly at the IM and red ripe (RR) stages. Within the SlPP2C gene family, the expression of SlPP2C, SlPP2C3, and SlPP2C4 increased after the MG stage; SlPP2C1 and SlPP2C5 peaked at the B3 stage, while SlPP2C2 and SlPP2C6 changed little during fruit development. Within the SlSnRK2 gene family, the expression of SlSnRK2.2, SlSnRK2.3, SlSnRK2.4, and SlSnRK2C was higher than that of other members during fruit development. Additionally, most SlPYL genes were down-regulated, while most SlPP2C and SlSnRK2 genes were up-regulated by dehydration in tomato leaf.

A Dynamic Analysis of Piezoelectric Strained Elements.

DTIC Science & Technology

1992-12-01

Type Quartz Crystal Plates ", IEEE SU- 29 (3), pp. 1 2 1 - 1 2 7 (1982). [107] L.K.Chau,High -frequency Long-wave Vibrations of Piezoelectric Ceramic ... Plate Excited with Voltage", Acta Acustica, 8 (5), pp. 300-310 (1983). [265] M.Ting-rong, "Forced Vibrations of Metal-Piezo- ceramic Thin Composite... ceramic and Metal Composite Thin Circular Plate with Different Diameter for Each Layer", Acta Acustica, 9 (5), pp. 298-310 (1984); Chinese J. Acoust., 2(3

Atorvastatin Alleviates Experimental Diabetic Cardiomyopathy by Regulating the GSK-3β-PP2Ac-NF-κB Signaling Axis

PubMed Central

Wu, Wen; Luo, Jie; Ye, Peng; Chen, Shao-liang; Hu, Zuo-ying

2016-01-01

Recent studies reported that atorvastatin (ATOR) alleviated progression of experimental diabetic cardiomyopathy (DCM), possibly by protecting against apoptosis. However, the underlying mechanisms of this protective effect remain unclear. Therefore, our study investigated the role of the glycogen synthase kinase (GSK)-3β-protein phosphatase 2A(PP2A)-NF-κB signaling pathway in the anti-apoptotic and cardioprotective effects of ATOR on cardiomyocytes cultured in high glucose (HG) and in DCM. Our results showed that, in HG-cultured cardiomyocytes, phosphorylation of GSK-3β was decreased, while that of the PP2A catalytic subunit C (PP2Ac) and IKK/IкBα was increased, followed by NF-кB nuclear translocation and apoptosis. IKK/IкBα phosphorylation and NF-кB nuclear translocation were also increased by treatment of cells with okadaic acid (OA), a selective PP2A inhibitor, or by silencing PP2Ac expression. The opposite results were obtained by silencing GSK-3β expression, which resulted in PP2Ac activation. Furthermore, IKK/IкBα phosphorylation and NF-кB nuclear translocation were markedly inhibited and apoptosis attenuated in cells treated with ATOR. These effects occurred through inactivation of GSK-3β and subsequent activation of PP2Ac. They were abolished by treatment of cells with OA or PP2Ac siRNA. In mice with type 1 diabetes mellitus, treatment with ATOR, at 10 mg-kg−1-d−1, significantly suppressed GSK-3β activation, IKK/IкBα phosphorylation, NF-кB nuclear translocation and caspase-3 activation, while also activating PP2Ac. Finally, improvements in histological abnormalities, fibrosis, apoptosis and cardiac dysfunction were observed in diabetic mice treated with ATOR. These findings demonstrated that ATOR protected against HG-induced apoptosis in cardiomyocytes and alleviated experimental DCM by regulating the GSK-3β-PP2A-NF-κB signaling pathway. PMID:27851811

A novel function of twins, B subunit of protein phosphatase 2A, in regulating actin polymerization.

PubMed

Yeh, Po-An; Chang, Ching-Jin

2017-01-01

Actin is an important component of the cytoskeleton and its polymerization is delicately regulated by several kinases and phosphatases. Heterotrimeric protein phosphatase 2A (PP2A) is a potent phosphatase that is crucial for cell proliferation, apoptosis, tumorigenesis, signal transduction, cytoskeleton arrangement, and neurodegeneration. To facilitate these varied functions, different regulators determine the different targets of PP2A. Among these regulators of PP2A, the B subunits in particular may be involved in cytoskeleton arrangement. However, little is known about the role of PP2A in actin polymerization in vivo. Using sophisticated fly genetics, we demonstrated a novel function for the fly B subunit, twins, to promote actin polymerization in varied tissue types, suggesting a broad and conserved effect. Furthermore, our genetic data suggest that twins may act upstream of the actin-polymerized-proteins, Moesin and Myosin-light-chain, and downstream of Rho to promote actin polymerization. This work opens a new avenue for exploring the biological functions of a PP2A regulator, twins, in cytoskeleton regulation.

A novel function of twins, B subunit of protein phosphatase 2A, in regulating actin polymerization

PubMed Central

Chang, Ching-Jin

2017-01-01

Actin is an important component of the cytoskeleton and its polymerization is delicately regulated by several kinases and phosphatases. Heterotrimeric protein phosphatase 2A (PP2A) is a potent phosphatase that is crucial for cell proliferation, apoptosis, tumorigenesis, signal transduction, cytoskeleton arrangement, and neurodegeneration. To facilitate these varied functions, different regulators determine the different targets of PP2A. Among these regulators of PP2A, the B subunits in particular may be involved in cytoskeleton arrangement. However, little is known about the role of PP2A in actin polymerization in vivo. Using sophisticated fly genetics, we demonstrated a novel function for the fly B subunit, twins, to promote actin polymerization in varied tissue types, suggesting a broad and conserved effect. Furthermore, our genetic data suggest that twins may act upstream of the actin-polymerized-proteins, Moesin and Myosin-light-chain, and downstream of Rho to promote actin polymerization. This work opens a new avenue for exploring the biological functions of a PP2A regulator, twins, in cytoskeleton regulation. PMID:28977036

Direct and Indirect Targeting of PP2A by Conserved Bacterial Type-III Effector Proteins

PubMed Central

Jin, Lin; Ham, Jong Hyun; Hage, Rosemary; Zhao, Wanying; Soto-Hernández, Jaricelis; Lee, Sang Yeol; Paek, Seung-Mann; Kim, Min Gab; Boone, Charles; Coplin, David L.; Mackey, David

2016-01-01

Bacterial AvrE-family Type-III effector proteins (T3Es) contribute significantly to the virulence of plant-pathogenic species of Pseudomonas, Pantoea, Ralstonia, Erwinia, Dickeya and Pectobacterium, with hosts ranging from monocots to dicots. However, the mode of action of AvrE-family T3Es remains enigmatic, due in large part to their toxicity when expressed in plant or yeast cells. To search for targets of WtsE, an AvrE-family T3E from the maize pathogen Pantoea stewartii subsp. stewartii, we employed a yeast-two-hybrid screen with non-lethal fragments of WtsE and a synthetic genetic array with full-length WtsE. Together these screens indicate that WtsE targets maize protein phosphatase 2A (PP2A) heterotrimeric enzyme complexes via direct interaction with B’ regulatory subunits. AvrE1, another AvrE-family T3E from Pseudomonas syringae pv. tomato strain DC3000 (Pto DC3000), associates with specific PP2A B’ subunit proteins from its susceptible host Arabidopsis that are homologous to the maize B’ subunits shown to interact with WtsE. Additionally, AvrE1 was observed to associate with the WtsE-interacting maize proteins, indicating that PP2A B’ subunits are likely conserved targets of AvrE-family T3Es. Notably, the ability of AvrE1 to promote bacterial growth and/or suppress callose deposition was compromised in Arabidopsis plants with mutations of PP2A genes. Also, chemical inhibition of PP2A activity blocked the virulence activity of both WtsE and AvrE1 in planta. The function of HopM1, a Pto DC3000 T3E that is functionally redundant to AvrE1, was also impaired in specific PP2A mutant lines, although no direct interaction with B’ subunits was observed. These results indicate that sub-component specific PP2A complexes are targeted by bacterial T3Es, including direct targeting by members of the widely conserved AvrE-family. PMID:27191168

Impaired adiponectin signaling contributes to disturbed catabolism of branched-chain amino acids in diabetic mice.

PubMed

Lian, Kun; Du, Chaosheng; Liu, Yi; Zhu, Di; Yan, Wenjun; Zhang, Haifeng; Hong, Zhibo; Liu, Peilin; Zhang, Lijian; Pei, Haifeng; Zhang, Jinglong; Gao, Chao; Xin, Chao; Cheng, Hexiang; Xiong, Lize; Tao, Ling

2015-01-01

The branched-chain amino acids (BCAA) accumulated in type 2 diabetes are independent contributors to insulin resistance. The activity of branched-chain α-keto acid dehydrogenase (BCKD) complex, rate-limiting enzyme in BCAA catabolism, is reduced in diabetic states, which contributes to elevated BCAA concentrations. However, the mechanisms underlying decreased BCKD activity remain poorly understood. Here, we demonstrate that mitochondrial phosphatase 2C (PP2Cm), a newly identified BCKD phosphatase that increases BCKD activity, was significantly downregulated in ob/ob and type 2 diabetic mice. Interestingly, in adiponectin (APN) knockout (APN(-/-)) mice fed with a high-fat diet (HD), PP2Cm expression and BCKD activity were significantly decreased, whereas BCKD kinase (BDK), which inhibits BCKD activity, was markedly increased. Concurrently, plasma BCAA and branched-chain α-keto acids (BCKA) were significantly elevated. APN treatment markedly reverted PP2Cm, BDK, BCKD activity, and BCAA and BCKA levels in HD-fed APN(-/-) and diabetic animals. Additionally, increased BCKD activity caused by APN administration was partially but significantly inhibited in PP2Cm knockout mice. Finally, APN-mediated upregulation of PP2Cm expression and BCKD activity were abolished when AMPK was inhibited. Collectively, we have provided the first direct evidence that APN is a novel regulator of PP2Cm and systematic BCAA levels, suggesting that targeting APN may be a pharmacological approach to ameliorating BCAA catabolism in the diabetic state. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Harpin-induced expression and transgenic overexpression of the phloem protein gene AtPP2-A1 in Arabidopsis repress phloem feeding of the green peach aphid Myzus persicae

PubMed Central

2011-01-01

Background Treatment of plants with HrpNEa, a protein of harpin group produced by Gram-negative plant pathogenic bacteria, induces plant resistance to insect herbivores, including the green peach aphid Myzus persicae, a generalist phloem-feeding insect. Under attacks by phloem-feeding insects, plants defend themselves using the phloem-based defense mechanism, which is supposed to involve the phloem protein 2 (PP2), one of the most abundant proteins in the phloem sap. The purpose of this study was to obtain genetic evidence for the function of the Arabidopsis thaliana (Arabidopsis) PP2-encoding gene AtPP2-A1 in resistance to M. persicae when the plant was treated with HrpNEa and after the plant was transformed with AtPP2-A1. Results The electrical penetration graph technique was used to visualize the phloem-feeding activities of apterous agamic M. persicae females on leaves of Arabidopsis plants treated with HrpNEa and an inactive protein control, respectively. A repression of phloem feeding was induced by HrpNEa in wild-type (WT) Arabidopsis but not in atpp2-a1/E/142, the plant mutant that had a defect in the AtPP2-A1 gene, the most HrpNEa-responsive of 30 AtPP2 genes. In WT rather than atpp2-a1/E/142, the deterrent effect of HrpNEa treatment on the phloem-feeding activity accompanied an enhancement of AtPP2-A1 expression. In PP2OETAt (AtPP2-A1-overexpression transgenic Arabidopsis thaliana) plants, abundant amounts of the AtPP2-A1 gene transcript were detected in different organs, including leaves, stems, calyces, and petals. All these organs had a deterrent effect on the phloem-feeding activity compared with the same organs of the transgenic control plant. When a large-scale aphid population was monitored for 24 hours, there was a significant decrease in the number of aphids that colonized leaves of HrpNEa-treated WT and PP2OETAt plants, respectively, compared with control plants. Conclusions The repression in phloem-feeding activities of M. persicae as a result of AtPP2-A1 overexpression, and as a deterrent effect of HrpNEa treatment in WT Arabidopsis rather than the atpp2-a1/E/142 mutant suggest that AtPP2-A1 plays a role in plant resistance to the insect, particularly at the phloem-feeding stage. The accompanied change of aphid population in leaf colonies suggests that the function of AtPP2-A1 is related to colonization of the plant. PMID:21226963

Harpin-induced expression and transgenic overexpression of the phloem protein gene AtPP2-A1 in Arabidopsis repress phloem feeding of the green peach aphid Myzus persicae.

PubMed

Zhang, Chunling; Shi, Haojie; Chen, Lei; Wang, Xiaomeng; Lü, Beibei; Zhang, Shuping; Liang, Yuan; Liu, Ruoxue; Qian, Jun; Sun, Weiwei; You, Zhenzhen; Dong, Hansong

2011-01-13

Treatment of plants with HrpNEa, a protein of harpin group produced by Gram-negative plant pathogenic bacteria, induces plant resistance to insect herbivores, including the green peach aphid Myzus persicae, a generalist phloem-feeding insect. Under attacks by phloem-feeding insects, plants defend themselves using the phloem-based defense mechanism, which is supposed to involve the phloem protein 2 (PP2), one of the most abundant proteins in the phloem sap. The purpose of this study was to obtain genetic evidence for the function of the Arabidopsis thaliana (Arabidopsis) PP2-encoding gene AtPP2-A1 in resistance to M. persicae when the plant was treated with HrpNEa and after the plant was transformed with AtPP2-A1. The electrical penetration graph technique was used to visualize the phloem-feeding activities of apterous agamic M. persicae females on leaves of Arabidopsis plants treated with HrpNEa and an inactive protein control, respectively. A repression of phloem feeding was induced by HrpNEa in wild-type (WT) Arabidopsis but not in atpp2-a1/E/142, the plant mutant that had a defect in the AtPP2-A1 gene, the most HrpNEa-responsive of 30 AtPP2 genes. In WT rather than atpp2-a1/E/142, the deterrent effect of HrpNEa treatment on the phloem-feeding activity accompanied an enhancement of AtPP2-A1 expression. In PP2OETAt (AtPP2-A1-overexpression transgenic Arabidopsis thaliana) plants, abundant amounts of the AtPP2-A1 gene transcript were detected in different organs, including leaves, stems, calyces, and petals. All these organs had a deterrent effect on the phloem-feeding activity compared with the same organs of the transgenic control plant. When a large-scale aphid population was monitored for 24 hours, there was a significant decrease in the number of aphids that colonized leaves of HrpNEa-treated WT and PP2OETAt plants, respectively, compared with control plants. The repression in phloem-feeding activities of M. persicae as a result of AtPP2-A1 overexpression, and as a deterrent effect of HrpNEa treatment in WT Arabidopsis rather than the atpp2-a1/E/142 mutant suggest that AtPP2-A1 plays a role in plant resistance to the insect, particularly at the phloem-feeding stage. The accompanied change of aphid population in leaf colonies suggests that the function of AtPP2-A1 is related to colonization of the plant.

Functional characterization of a second pedal peptide/orcokinin-type neuropeptide signaling system in the starfish Asterias rubens.

PubMed

Lin, Ming; Egertová, Michaela; Zampronio, Cleidiane G; Jones, Alexandra M; Elphick, Maurice R

2018-04-01

Molluscan pedal peptides (PPs) and arthropod orcokinins (OKs) are prototypes of a family of neuropeptides that have been identified in several phyla. Recently, starfish myorelaxant peptide (SMP) was identified as a PP/OK-type neuropeptide in the starfish Patiria pectinifera (phylum Echinodermata). Furthermore, analysis of transcriptome sequence data from the starfish Asterias rubens revealed two PP/OK-type precursors: an SMP-type precursor (A. rubens PP-like neuropeptide precursor 1; ArPPLNP1) and a second precursor (ArPPLNP2). We reported previously a detailed analysis of ArPPLNP1 expression in A. rubens and here we report the first functional characterization ArPPLNP2-derived neuropeptides. Sequencing of a cDNA encoding ArPPLNP2 revealed that it comprises eleven related neuropeptides (ArPPLN2a-k), the structures of several of which were confirmed using mass spectrometry. Analysis of the expression of ArPPLNP2 and neuropeptides derived from this precursor using mRNA in situ hybridization and immunohistochemistry revealed a widespread distribution, including expression in radial nerve cords, circumoral nerve ring, digestive system, tube feet and innervation of interossicular muscles. In vitro pharmacology revealed that the ArPPLNP2-derived neuropeptide ArPPLN2h has no effect on the contractility of tube feet or the body wall-associated apical muscle, contrasting with the relaxing effect of ArPPLN1b (ArSMP) on these preparations. ArPPLN2h does, however, cause dose-dependent relaxation of cardiac stomach preparations, with greater potency/efficacy than ArPPLN1b and with similar potency/efficacy to the SALMFamide neuropeptide S2. In conclusion, there are similarities in the expression patterns of ArPPLNP1 and ArPPLNP2 but our data also indicate specialization in the roles of neuropeptides derived from these two PP/OK-type precursors in starfish. © 2017 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

Two highly-related regulatory subunits of PP2A exert opposite effects on TGF-β/Activin/Nodal signalling

PubMed Central

Batut, Julie; Schmierer, Bernhard; Cao, Jing; Raftery, Laurel A.; Hill, Caroline S.; Howell, Michael

2016-01-01

Summary We identify Bα (PPP2R2A) and Bδ (PPP2R2D), two highly-related members of the B family of regulatory subunits of the protein phosphatase PP2A, as important modulators of TGF-β/Activin/Nodal signalling, which affect the pathway in opposite ways. Knockdown of Bα in Xenopus embryos or mammalian tissue culture cells suppresses TGF-β/Activin/Nodal-dependent responses, whereas knockdown of Bδ enhances these responses. Moreover, in Drosophila, overexpression of Smad2 rescues a severe wing phenotype caused by overexpression of the single Drosophila PP2A B subunit, Twins. We show that in vertebrates Bα enhances TGF-β/Activin/Nodal signalling by stabilising the basal levels of type I receptor, whereas Bδ negatively modulates these pathways by restricting receptor activity. Thus, these highly-related members of the same subfamily of PP2A regulatory subunits differentially regulate TGF-β/Activin/Nodal signalling to elicit opposing biological outcomes. PMID:18697906

Structural basis and functions of abscisic acid receptors PYLs

PubMed Central

Zhang, Xing L.; Jiang, Lun; Xin, Qi; Liu, Yang; Tan, Jian X.; Chen, Zhong Z.

2015-01-01

Abscisic acid (ABA) plays a key role in many developmental processes and responses to adaptive stresses in plants. Recently, a new family of nucleocytoplasmic PYR/PYL/RCAR (PYLs) has been identified as bona fide ABA receptors. PYLs together with protein phosphatases type-2C (PP2Cs), Snf1 (Sucrose-non-fermentation 1)-related kinases subfamily 2 (SnRK2s) and downstream substrates constitute the core ABA signaling network. Generally, PP2Cs inactivate SnRK2s kinases by physical interaction and direct dephosphorylation. Upon ABA binding, PYLs change their conformations and then contact and inhibit PP2Cs, thus activating SnRK2s. Here, we reviewed the recent progress in research regarding the structures of the core signaling pathways of ABA, including the (+)-ABA, (−)-ABA and ABA analogs pyrabactin as well as 6AS perception by PYLs, SnRK2s mimicking PYLs in binding PP2Cs. PYLs inhibited PP2Cs in both the presence and absence of ABA and activated SnRK2s. The present review elucidates multiple ABA signal perception and transduction by PYLs, which might shed light on how to design small chemical compounds for improving plant performance in the future. PMID:25745428

Thctf1 transcription factor of Trichoderma harzianum is involved in 6-pentyl-2H-pyran-2-one production and antifungal activity.

PubMed

Rubio, M Belén; Hermosa, Rosa; Reino, José Luis; Collado, Isidro G; Monte, Enrique

2009-01-01

We describe the cloning and characterization of the Trichoderma harzianum Thctf1 gene, which shows high sequence identity with a transcription factor gene of Fusarium solani f. sp. pisi. In T. harzianum, disruption of the Thctf1 gene by homologous recombination gave rise to transformants that in plate experiments did not show the yellow pigmentation observed in the wild-type strain. In several Trichoderma spp. a yellow pigmentation and a coconut aroma have been related to the production of 6-pentyl-2H-pyran-2-one (6PP) compounds. Prompted by this, we explored whether the loss of pigmentation in the Thctf1 null mutants of T. harzianum might be related to the synthesis of 6PP. Chromatographic and spectroscopic analyses revealed that the disruptants did not produce two secondary metabolites, derived from 6PP and not previously described in the Trichoderma genus, that are present in wild-type culture filtrates. Since 6PP is a recognized antifungal compound, this ability was analyzed in both the disruptants and wild-type, observing that the Thctf1 null mutants of T. harzianum had reduced antimicrobial capacity. Our results point to the significant role of THCTF1 in the production of secondary metabolites and in the antifungal activity of T. harzianum.

SCFAtPP2-B11 modulates ABA signaling by facilitating SnRK2.3 degradation in Arabidopsis thaliana

PubMed Central

Ren, Ziyin; Zhi, Liya; Yao, Bin; Su, Chao; Liu, Liu; Li, Xia

2017-01-01

The phytohormone abscisic acid (ABA) is an essential part of the plant response to abiotic stressors such as drought. Upon the perception of ABA, pyrabactin resistance (PYR)/PYR1-like (PYL)/regulatory components of ABA receptor (RCAR) proteins interact with co-receptor protein phosphatase type 2Cs to permit activation Snf1-related protein kinase2 (SnRK2) kinases, which switch on ABA signaling by phosphorylating various target proteins. Thus, SnRK2 kinases are central regulators of ABA signaling. However, the mechanisms that regulate SnRK2 degradation remain elusive. Here, we show that SnRK2.3 is degradated by 26S proteasome system and ABA promotes its degradation. We found that SnRK2.3 interacts with AtPP2-B11 directly. AtPP2-B11 is an F-box protein that is part of a SKP1/Cullin/F-box E3 ubiquitin ligase complex that negatively regulates plant responses to ABA by specifically promoting the degradation of SnRK2.3. AtPP2-B11 was induced by ABA, and the knockdown of AtPP2-B11 expression markedly increased the ABA sensitivity of plants during seed germination and postgerminative development. Overexpression of AtPP2-B11 does not affect ABA sensitivity, but inhibits the ABA hypersensitive phenotypes of SnRK2.3 overexpression lines. These results reveal a novel mechanism through which AtPP2-B11 specifically degrades SnRK2.3 to attenuate ABA signaling and the abiotic stress response in Arabidopsis. PMID:28787436

Crystal structure of the human Tip41 orthologue, TIPRL, reveals a novel fold and a binding site for the PP2Ac C-terminus

PubMed Central

Scorsato, Valéria; Lima, Tatiani B.; Righetto, Germanna L.; Zanchin, Nilson I. T.; Brandão-Neto, José; Sandy, James; Pereira, Humberto D’Muniz; Ferrari, Állan J. R.; Gozzo, Fabio C.; Smetana, Juliana H. C.; Aparicio, Ricardo

2016-01-01

TOR signaling pathway regulator-like (TIPRL) is a regulatory protein which inhibits the catalytic subunits of Type 2A phosphatases. Several cellular contexts have been proposed for TIPRL, such as regulation of mTOR signaling, inhibition of apoptosis and biogenesis and recycling of PP2A, however, the underlying molecular mechanism is still poorly understood. We have solved the crystal structure of human TIPRL at 2.15 Å resolution. The structure is a novel fold organized around a central core of antiparallel beta-sheet, showing an N-terminal α/β region at one of its surfaces and a conserved cleft at the opposite surface. Inside this cleft, we found a peptide derived from TEV-mediated cleavage of the affinity tag. We show by mutagenesis, pulldown and hydrogen/deuterium exchange mass spectrometry that this peptide is a mimic for the conserved C-terminal tail of PP2A, an important region of the phosphatase which regulates holoenzyme assembly, and TIPRL preferentially binds the unmodified version of the PP2A-tail mimetic peptide DYFL compared to its tyrosine-phosphorylated version. A docking model of the TIPRL-PP2Ac complex suggests that TIPRL blocks the phosphatase’s active site, providing a structural framework for the function of TIPRL in PP2A inhibition. PMID:27489114

Crystal structure of the human Tip41 orthologue, TIPRL, reveals a novel fold and a binding site for the PP2Ac C-terminus

NASA Astrophysics Data System (ADS)

Scorsato, Valéria; Lima, Tatiani B.; Righetto, Germanna L.; Zanchin, Nilson I. T.; Brandão-Neto, José; Sandy, James; Pereira, Humberto D.'Muniz; Ferrari, Állan J. R.; Gozzo, Fabio C.; Smetana, Juliana H. C.; Aparicio, Ricardo

2016-08-01

TOR signaling pathway regulator-like (TIPRL) is a regulatory protein which inhibits the catalytic subunits of Type 2A phosphatases. Several cellular contexts have been proposed for TIPRL, such as regulation of mTOR signaling, inhibition of apoptosis and biogenesis and recycling of PP2A, however, the underlying molecular mechanism is still poorly understood. We have solved the crystal structure of human TIPRL at 2.15 Å resolution. The structure is a novel fold organized around a central core of antiparallel beta-sheet, showing an N-terminal α/β region at one of its surfaces and a conserved cleft at the opposite surface. Inside this cleft, we found a peptide derived from TEV-mediated cleavage of the affinity tag. We show by mutagenesis, pulldown and hydrogen/deuterium exchange mass spectrometry that this peptide is a mimic for the conserved C-terminal tail of PP2A, an important region of the phosphatase which regulates holoenzyme assembly, and TIPRL preferentially binds the unmodified version of the PP2A-tail mimetic peptide DYFL compared to its tyrosine-phosphorylated version. A docking model of the TIPRL-PP2Ac complex suggests that TIPRL blocks the phosphatase’s active site, providing a structural framework for the function of TIPRL in PP2A inhibition.

Protease Activated Receptor-2 Mediates Activated Protein C–Induced Cutaneous Wound Healing via Inhibition of p38

PubMed Central

Julovi, Sohel M.; Xue, Meilang; Dervish, Suat; Sambrook, Philip N.; March, Lyn; Jackson, Christopher John

2011-01-01

Activated protein C (APC) is a natural anticoagulant that exerts anti-inflammatory and cytoprotective properties mediated through the protease activated receptor (PAR)-1. APC can also proteolytically cleave PAR-2, although subsequent function is unknown. On the basis of recent evidence that APC promotes wound healing, the aim of this study was to determine whether APC acts through PARs to heal murine excisional wounds or to regulate human cultured keratinocyte function and to determine the signaling mechanisms. Topical administration of APC accelerated wound healing in wild-type mice and, unexpectedly, in PAR-1 knockout mice. PAR-2 knockout mice healed significantly slower than wild-type mice, and healing was not altered by adding APC, indicating that APC acts through PAR-2 to heal wounds. In cultured human primary keratinocytes, APC enhanced PAR-2, stimulated proliferation, activated phosphatidylinositol 3-kinase/Src/Akt, and inhibited phosphorylated (P)-p38. Inhibiting PAR-1 or PAR-2, by small-interfering RNA or blocking antibody, reversed APC-induced keratinocyte proliferation and Akt activation. Blocking PAR-2, but not PAR-1, reversed the inhibition of P-p38 by APC. Furthermore, inhibition of P-p38 accelerated wound healing in wild-type mice. In summary, although APC acts through both PAR-1 and PAR-2 to activate Akt and to increase keratinocyte proliferation, APC-induced murine wound healing depends on PAR-2 activity and inhibition of P-p38. PMID:21907694

Sperm motility development in the epididymis is associated with decreased glycogen synthase kinase-3 and protein phosphatase 1 activity.

PubMed

Vijayaraghavan, S; Stephens, D T; Trautman, K; Smith, G D; Khatra, B; da Cruz e Silva, E F; Greengard, P

1996-03-01

Immotile bovine caput epididymal sperm contain levels of protein phosphatase activity twofold higher than do mature motile caudal sperm. Comparison of the inhibition profiles of endogenous phosphatase activities detected by okadaic acid (OA) and calyculin A (CA) revealed a pattern consistent with the predominance of a type 1 protein phosphatase (PP1). Immunoblot analysis identified PP1 gamma 2 (the testis-specific isoform of PP1) as the only PP1 isoform in sperm and showed little protein phosphatase 2A (PP2A). In addition, of the known PP1 inhibitors, i.e., DARPP-32, inhibitor 1 (I1), and inhibitor 2 (I2), only I2-like activity was detected in sperm. Inhibition of PP1 by the heat-stable I2-like activity purified from sperm could be reversed with purified glycogen synthase kinase-3 (GSK-3). Furthermore, sperm extracts contain an inactive complex of PP1 and I2 (termed PP1I) that could also be activated by purified GSK-3. The presence of GSK-3 in sperm was demonstrated by activation of purified PP1I, and quantitation revealed that immotile caput sperm contained sixfold higher GSK-3 activity than motile caudal sperm. Immunoblot analysis confirmed the expression of GSK-3 in sperm and revealed the occurrence of both the alpha and beta isoforms. Our findings suggest that the higher PP1 activity measured in immotile sperm, presumably due to higher GSK-3 activity, is responsible for holding motility in check. This conclusion was supported by the observation that the phosphatase inhibitors OA and CA, at micromolar and nanomolar levels, respectively, were able to induce motility in completely immotile bovine caput epididymal sperm and to stimulate the kinetic activity of mature caudal sperm. The intrasperm levels of cAMP, pH, and calcium were unaltered by treatment with these inhibitors. The results suggest a biochemical basis for the development and regulation of sperm motility and a possible physiological role for the PP1/I2/GSK-3 system.

Analysis of Vernier Scans during the PP2PP run in 2009 (pp at 100 GeV/beam)

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

Drees, A.

2011-12-13

At the end of RHIC's 2009 operation a dedicated run for the PP2PP experiment (part of the STAR experiment) took place from Jun 29 to Jul 06 2009. Polarized protons were accelerated to 100 GeV using ramp-file pp100-90pp2pp with a {beta}* = 22 m in IR6. Since only transverse polarization was required no rotator ramp was in use. The PP2PP experiment consists mainly of two Roman Pot detectors (one horizontal and one vertical) on either side of IR6 in the outgoing-beam arms between the Q3 and Q4 magnets. The yellow pots are in sector 5, the blue ones in sectormore » 6. Roman Pot type detectors are installed inside the beampipe causing an accelerator safety concern. To address this concern there is a limit to the allowable total beam current in the machine while Roman Pots are enabled to move closer to the beam. This limit was set to a motion limit of 5 mm from the center of the beampipe and 50 {center_dot} 10{sup 11} beam current per ring. In order to reduce the background in the detectors, beams were scraped using the RHIC collimator system prior to moving the pots closer. This was typically repeated several times throughout a store since beam halo reforms over the course of hours.« less

[Preparation and activity validation of PP7 bacteriophage-like particles displaying PAP114-128 peptide].

PubMed

Sun, Yanli; Sun, Yanhua

2016-10-01

Objective To obtain the PP7 bacteriophage-like particles carrying the peptide of prostatic acid phosphatase PAP 114-128 , and prove that they retain the original biological activity. Methods First, the plasmid pETDuet-2PP7 was constructed as follows: the gene of PP7 coat protein dimer was amplified by gene mutation combined with overlapping PCR technology, and inserted into the vector pETDuet-1. Following that, the plasmid pETDuet-2PP7-PAP 114-128 was constructed as follows: the PP7 coat protein gene carrying the coding gene of PAP 114-128 peptide was amplified using PCR, and then inserted into the vector pETDuet-2PP7. Both pETDuet-2PP7 and pETDuet-2PP7-PAP 114-128 were transformed into E.coli and expressed. The expression product was verified by SDS-PAGE, double immunodiffusion assay and ELISA. Results The gene fragment of PP7 coat protein dimer was obtained by overlapping PCR using Ex Taq DNA polymerase, and the antigenicity of its expression product was the same as that of the coat protein of wild-type PP7 bacteriophage. Moreover, the PAP 114-128 peptide epitope that was displayed on the surface of PP7 bacteriophage was identical with the corresponding epitope of natural human PAP, and it was able to induce high levels of antibodies. Conclusion The gene of PP7 coat protein dimer with repeated sequences can be prepared by gene mutation combined with overlapping PCR. Based on this, PP7 bacteriophage-like particles carrying PAP peptide can be prepared, which not only solves the problem of the instability of the peptides, but also lays a foundation for the study on their delivery and function.

Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size1[OPEN

PubMed Central

Wang, Liang; Lu, Qingtao

2015-01-01

Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population. PMID:26504138

Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size.

PubMed

Wang, Liang; Lu, Qingtao; Wen, Xiaogang; Lu, Congming

2015-12-01

Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population. © 2015 American Society of Plant Biologists. All Rights Reserved.

Gardenia jasminoides Encodes an Inhibitor-2 Protein for Protein Phosphatase Type 1

NASA Astrophysics Data System (ADS)

Gao, Lan; Li, Hao-Ming

2017-08-01

Protein phosphatase-1 (PP1) regulates diverse, essential cellular processes such as cell cycle progression, protein synthesis, muscle contraction, carbohydrate metabolism, transcription and neuronal signaling. Inhibitor-2 (I-2) can inhibit the activity of PP1 and has been found in diverse organisms. In this work, a Gardenia jasminoides fruit cDNA library was constructed, and the GjI-2 cDNA was isolated from the cDNA library by sequencing method. The GjI-2 cDNA contains a predicted 543 bp open reading frame that encodes 180 amino acids. The bioinformatics analysis suggested that the GjI-2 has conserved PP1c binding motif, and contains a conserved phosphorylation site, which is important in regulation of its activity. The three-dimensional model structure of GjI-2 was buite, its similar with the structure of I-2 from mouse. The results suggest that GjI-2 has relatively conserved RVxF, FxxR/KxR/K and HYNE motif, and these motifs are involved in interaction with PP1.

Identification of residues within the African swine fever virus DP71L protein required for dephosphorylation of translation initiation factor eIF2α and inhibiting activation of pro-apoptotic CHOP

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

Barber, Claire; Netherton, Chris; Goatley, Lynnett

The African swine fever virus DP71L protein recruits protein phosphatase 1 (PP1) to dephosphorylate the translation initiation factor 2α (eIF2α) and avoid shut-off of global protein synthesis and downstream activation of the pro-apoptotic factor CHOP. Residues V16 and F18A were critical for binding of DP71L to PP1. Mutation of this PP1 binding motif or deletion of residues between 52 and 66 reduced the ability of DP71L to cause dephosphorylation of eIF2α and inhibit CHOP induction. The residues LSAVL, between 57 and 61, were also required. PP1 was co-precipitated with wild type DP71L and the mutant lacking residues 52- 66 ormore » the LSAVL motif, but not with the PP1 binding motif mutant. The residues in the LSAVL motif play a critical role in DP71L function but do not interfere with binding to PP1. Instead we propose these residues are important for DP71L binding to eIF2α. - Highlights: •The African swine fever virus DP71L protein recruits protein phosphatase 1 (PP1) to dephosphorylate translation initiation factor eIF2α (eIF2α). •The residues V{sup 16}, F{sup 18} of DP71L are required for binding to the α, β and γ isoforms of PP1 and for DP71L function. •The sequence LSAVL downstream from the PP1 binding site (residues 57–61) are also important for DP71L function. •DP71L mutants of the LSAVL sequence retain ability to co-precipitate with PP1 showing these sequences have a different role to PP1 binding.« less

Okadaic acid overcomes the blocked cell cycle caused by depleting Cdc2-related kinases in Trypanosoma brucei

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

Li Ziyin; Tu Xiaoming; Wang, Ching C.

2006-11-01

Mitosis and cytokinesis are highly coordinated in eukaryotic cells. But procyclic-form Trypanosoma brucei under G1 or mitotic arrest is still capable of dividing, resulting in anucleate daughter cells (zoids). Okadaic acid (OKA), an inhibitor of protein phosphatases PP1 and PP2A, is known to inhibit kinetoplast replication and cell division yielding multinucleate cells with single kinetoplasts. However, when OKA was applied to cells arrested in G1 or G2/M phase via RNAi knockdown of specific cdc2-related kinases (CRKs), DNA synthesis and nuclear division were resumed without kinetoplast replication or cell division, resulting in multinucleate cells as in the wild type. Cells arrestedmore » in G2/M via depleting the mitotic cyclin CycB2 or an aurora B kinase homologue TbAUK1 were, however, not released by OKA treatment. The phenomenon is thus similar to the OKA activation of Cdc2 in Xenopus oocyte by inhibiting PP2A [Maton, et al., Differential regulation of Cdc2 and Aurora-A in Xenopus oocytes: a crucial role of phosphatase 2A. J. Cell Sci. 118 (2005) 2485-2494]. A simultaneous knockdown of the seven PP1s or the PP2A catalytic subunit in T. brucei by RNA interference did not, however, result in multinucleate cells. This could be explained by assuming a negative regulation, either directly or indirectly, of CRK by an OKA-sensitive phosphatase, which could be a PP2A as in the Xenopus oocyte and a positive regulation of kinetoplast replication by an OKA-susceptible protein(s). Test of a PP2A-specific inhibitor, fostriecin, on cells arrested in G2/M via CRK depletion or a knockdown of the PP2A catalytic subunit from the CRK-depleted cells both showed a partial lift of the G2/M block without forming multinucleate cells. These observations support the abovementioned assumption and suggest the presence of a novel OKA-sensitive protein(s) regulating kinetoplast replication that still remains to be identified.« less

PP2B/calcineurin-mediated desensitization of TRPV1 does not require AKAP150

PubMed Central

Por, Elaine D.; Samelson, Bret K.; Belugin, Sergei; Akopian, Armen N.; Scott, John D.; Jeske, Nathaniel A.

2011-01-01

Activation of protein kinases and phosphatases at the plasma membrane often initiates agonist-dependent signalling events. In sensory neurons, AKAP150 (A-kinase-anchoring protein 150) orientates PKA (protein kinase A), PKC (protein kinase C) and the Ca2+/calmodulin-dependent PP2B (protein phosphatase 2B, also known as calcineurin) towards membrane-associated substrates. Recent evidence indicates that AKAP150-anchored PKA and PKC phosphorylate and sensitize the TRPV1 (transient receptor potential subfamily V type 1 channel, also known as the capsaicin receptor). In the present study, we explore the hypothesis that an AKAP150-associated pool of PP2B catalyses the dephosphorylation and desensitization of TRPV1. Biochemical, electrophysiological and cell-based experiments indicate that PP2B associates with AKAP150 and TRPV1 in cultured TG (trigeminal ganglia) neurons. Gene silencing of AKAP150 reduces basal phosphorylation of TRPV1. However, functional studies in neurons isolated from AKAP150−/− mice indicate that the anchoring protein is not required for pharmacological desensitization of TRPV1. Behavioural analysis of AKAP150−/− mice further support this notion, demonstrating that agonist-stimulated desensitization of TRPV1 is sensitive to PP2B inhibition and does not rely on AKAP150. These findings allow us to conclude that pharmacological desensitization of TRPV1 by PP2B may involve additional regulatory components. PMID:20883208

PP2B/calcineurin-mediated desensitization of TRPV1 does not require AKAP150.

PubMed

Por, Elaine D; Samelson, Bret K; Belugin, Sergei; Akopian, Armen N; Scott, John D; Jeske, Nathaniel A

2010-12-15

Activation of protein kinases and phosphatases at the plasma membrane often initiates agonist-dependent signalling events. In sensory neurons, AKAP150 (A-kinase-anchoring protein 150) orientates PKA (protein kinase A), PKC (protein kinase C) and the Ca2+/calmodulin-dependent PP2B (protein phosphatase 2B, also known as calcineurin) towards membrane-associated substrates. Recent evidence indicates that AKAP150-anchored PKA and PKC phosphorylate and sensitize the TRPV1 (transient receptor potential subfamily V type 1 channel, also known as the capsaicin receptor). In the present study, we explore the hypothesis that an AKAP150-associated pool of PP2B catalyses the dephosphorylation and desensitization of TRPV1. Biochemical, electrophysiological and cell-based experiments indicate that PP2B associates with AKAP150 and TRPV1 in cultured TG (trigeminal ganglia) neurons. Gene silencing of AKAP150 reduces basal phosphorylation of TRPV1. However, functional studies in neurons isolated from AKAP150-/- mice indicate that the anchoring protein is not required for pharmacological desensitization of TRPV1. Behavioural analysis of AKAP150-/- mice further support this notion, demonstrating that agonist-stimulated desensitization of TRPV1 is sensitive to PP2B inhibition and does not rely on AKAP150. These findings allow us to conclude that pharmacological desensitization of TRPV1 by PP2B may involve additional regulatory components.

Diversity in genomic organisation, developmental regulation and distribution of the murine PR72/B" subunits of protein phosphatase 2A

PubMed Central

Zwaenepoel, Karen; Louis, Justin V; Goris, Jozef; Janssens, Veerle

2008-01-01

Background Protein phosphatase 2A (PP2A) is a serine/threonine-specific phosphatase displaying vital functions in growth and development through its role in various signalling pathways. PP2A holoenzymes comprise a core dimer composed of a catalytic C and a structural A subunit, which can associate with a variable B-type subunit. The importance of the B-type subunits for PP2A regulation cannot be overestimated as they determine holoenzyme localisation, activity and substrate specificity. Three B-type subunit families have been identified: PR55/B, PR61/B' and PR72/B", of which the latter is currently the least characterised. Results We deduced the sequences and genomic organisation of the different murine PR72/B" isoforms: three genes encode nine isoforms, five of which are abundantly expressed and give rise to genuine PP2A subunits. Thereby, one novel subunit was identified. Using Northern blotting, we examined the tissue-specific and developmental expression of these subunits. All subunits are highly expressed in heart, suggesting an important cardiac function. Immunohistochemical analysis revealed a striated expression pattern of PR72 and PR130 in heart and skeletal muscle, but not in bladder smooth muscle. The subcellular localisation and cell cycle regulatory ability of several PR72/B" isoforms were determined, demonstrating differences as well as similarities. Conclusion In contrast to PR55/B and PR61/B', the PR72/B" family seems evolutionary more divergent, as only two of the murine genes have a human orthologue. We have integrated these results in a more consistent nomenclature of both human and murine PR72/B" genes and their transcripts/proteins. Our results provide a platform for the future generation of PR72/B" knockout mice. PMID:18715506

The RCN1-encoded A subunit of protein phosphatase 2A increases phosphatase activity in vivo

NASA Technical Reports Server (NTRS)

Deruere, J.; Jackson, K.; Garbers, C.; Soll, D.; Delong, A.; Evans, M. L. (Principal Investigator)

1999-01-01

Protein phosphatase 2A (PP2A), a heterotrimeric serine/threonine-specific protein phosphatase, comprises a catalytic C subunit and two distinct regulatory subunits, A and B. The RCN1 gene encodes one of three A regulatory subunits in Arabidopsis thaliana. A T-DNA insertion mutation at this locus impairs root curling, seedling organ elongation and apical hypocotyl hook formation. We have used in vivo and in vitro assays to gauge the impact of the rcn1 mutation on PP2A activity in seedlings. PP2A activity is decreased in extracts from rcn1 mutant seedlings, and this decrease is not due to a reduction in catalytic subunit expression. Roots of mutant seedlings exhibit increased sensitivity to the phosphatase inhibitors okadaic acid and cantharidin in organ elongation assays. Shoots of dark-grown, but not light-grown seedlings also show increased inhibitor sensitivity. Furthermore, cantharidin treatment of wild-type seedlings mimics the rcn1 defect in root curling, root waving and hypocotyl hook formation assays. In roots of wild-type seedlings, RCN1 mRNA is expressed at high levels in root tips, and accumulates to lower levels in the pericycle and lateral root primordia. In shoots, RCN1 is expressed in the apical hook and the basal, rapidly elongating cells in etiolated hypocotyls, and in the shoot meristem and leaf primordia of light-grown seedlings. Our results show that the wild-type RCN1-encoded A subunit functions as a positive regulator of the PP2A holoenzyme, increasing activity towards substrates involved in organ elongation and differential cell elongation responses such as root curling.

Proposal of Mucilaginibacter phyllosphaerae sp. nov. isolated from the phyllosphere of Galium album.

PubMed

Aydogan, Ebru L; Busse, Hans-Jürgen; Moser, Gerald; Müller, Christoph; Kämpfer, Peter; Glaeser, Stefanie P

2016-10-01

A pink-pigmented, Gram-stain-negative, rod-shaped, non-spore-forming bacterial strain, PP-F2F-G21T, was isolated from the phyllosphere of Galium album. Phylogenetic analysis of the nearly full-length 16S rRNA gene sequence of strain PP-F2F-G21T showed the closest relationship to type strains of the species Mucilaginibacter lutimaris (97.7 %), Mucilaginibacter soli (97.3 %) and Mucilaginibacter rigui (97.1 %). Sequence similarities to all other type strains were below 97 %. The predominant cellular fatty acids of strain PP-F2F-G21T are C16 : 1 ω7c/iso-C15 : 0 2-OH (measured as summed feature 3 fatty acids) and iso-C15 : 0 followed by iso-C17 : 0 3-OH, C16 : 1 ω5c and C16 : 0. The major compound in the polyamine pattern was sym-homospermidine and the diamino acid of the peptidoglycan was meso-diaminopimelic acid. The quinone system was exclusively composed of menaquinone MK-7. The polar lipid profile contained the major lipid phosphatidylethanolamine and in addition 18 unidentified lipids. Based on phylogenetic, chemotaxonomic and phenotypic analyses, we propose a novel species of the genus Mucilaginibacter named Mucilaginibacter phyllosphaeraesp. nov. The type strain is PP-F2F-G21T (=CCM 8625T=CIP 110921T=LMG 29118T).

Effect of multi-strain probiotics (multi-strain microbial cell preparation) on glycemic control and other diabetes-related outcomes in people with type 2 diabetes: a randomized controlled trial.

PubMed

Firouzi, Somayyeh; Majid, Hazreen Abdul; Ismail, Amin; Kamaruddin, Nor Azmi; Barakatun-Nisak, Mohd-Yusof

2017-06-01

Evidence of a possible connection between gut microbiota and several physiological processes linked to type 2 diabetes is increasing. However, the effect of multi-strain probiotics in people with type 2 diabetes remains unclear. This study investigated the effect of multi-strain microbial cell preparation-also refers to multi-strain probiotics-on glycemic control and other diabetes-related outcomes in people with type 2 diabetes. A randomized, double-blind, parallel-group, controlled clinical trial. Diabetes clinic of a teaching hospital in Kuala Lumpur, Malaysia. A total of 136 participants with type 2 diabetes, aged 30-70 years, were recruited and randomly assigned to receive either probiotics (n = 68) or placebo (n = 68) for 12 weeks. Primary outcomes were glycemic control-related parameters, and secondary outcomes were anthropomorphic variables, lipid profile, blood pressure and high-sensitivity C-reactive protein. The Lactobacillus and Bifidobacterium quantities were measured before and after intervention as an indicator of successful passage of the supplement through gastrointestinal tract. Intention-to-treat (ITT) analysis was performed on all participants, while per-protocol (PP) analysis was performed on those participants who had successfully completed the trial with good compliance rate. With respect to primary outcomes, glycated hemoglobin decreased by 0.14 % in the probiotics and increased by 0.02 % in the placebo group in PP analysis (p < 0.05, small effect size of 0.050), while these changes were not significant in ITT analysis. Fasting insulin increased by 1.8 µU/mL in placebo group and decreased by 2.9 µU/mL in probiotics group in PP analysis. These changes were significant between groups at both analyses (p < 0.05, medium effect size of 0.062 in PP analysis and small effect size of 0.033 in ITT analysis). Secondary outcomes did not change significantly. Probiotics successfully passed through the gastrointestinal tract. Probiotics modestly improved HbA1c and fasting insulin in people with type 2 diabetes.

A RNA Interference Screen Identifies the Protein Phosphatase 2A Subunit PR55γ as a Stress-Sensitive Inhibitor of c-SRC

PubMed Central

Eichhorn, Pieter J. A; Creyghton, Menno P; Wilhelmsen, Kevin; van Dam, Hans; Bernards, René

2007-01-01

Protein Phosphatase type 2A (PP2A) represents a family of holoenzyme complexes with diverse biological activities. Specific holoenzyme complexes are thought to be deregulated during oncogenic transformation and oncogene-induced signaling. Since most studies on the role of this phosphatase family have relied on the use of generic PP2A inhibitors, the contribution of individual PP2A holoenzyme complexes in PP2A-controlled signaling pathways is largely unclear. To gain insight into this, we have constructed a set of shRNA vectors targeting the individual PP2A regulatory subunits for suppression by RNA interference. Here, we identify PR55γ and PR55δ as inhibitors of c-Jun NH2-terminal kinase (JNK) activation by UV irradiation. We show that PR55γ binds c-SRC and modulates the phosphorylation of serine 12 of c-SRC, a residue we demonstrate to be required for JNK activation by c-SRC. We also find that the physical interaction between PR55γ and c-SRC is sensitive to UV irradiation. Our data reveal a novel mechanism of c-SRC regulation whereby in response to stress c-SRC activity is regulated, at least in part, through loss of the interaction with its inhibitor, PR55γ. PMID:18069897

Alpha-, Delta- and PP-cells

PubMed Central

Brereton, Melissa F.; Vergari, Elisa; Zhang, Quan

2015-01-01

Islet non-β-cells, the α- δ- and pancreatic polypeptide cells (PP-cells), are important components of islet architecture and intercellular communication. In α-cells, glucagon is found in electron-dense granules; granule exocytosis is calcium-dependent via P/Q-type Ca2+-channels, which may be clustered at designated cell membrane sites. Somatostatin-containing δ-cells are neuron-like, creating a network for intra-islet communication. Somatostatin 1-28 and 1-14 have a short bioactive half-life, suggesting inhibitory action via paracrine signaling. PP-cells are the most infrequent islet cell type. The embryologically separate ventral pancreas anlage contains PP-rich islets that are morphologically diffuse and α-cell deficient. Tissue samples taken from the head region are unlikely to be representative of the whole pancreas. PP has anorexic effects on gastro-intestinal function and alters insulin and glucagon secretion. Islet architecture is disrupted in rodent diabetic models, diabetic primates and human Type 1 and Type 2 diabetes, with an increased α-cell population and relocation of non-β-cells to central areas of the islet. In diabetes, the transdifferentiation of non-β-cells, with changes in hormone content, suggests plasticity of islet cells but cellular function may be compromised. Understanding how diabetes-related disordered islet structure influences intra-islet cellular communication could clarify how non-β-cells contribute to the control of islet function. PMID:26216135

Negative regulation of protein phosphatase 2Cbeta by ISG15 conjugation.

PubMed

Takeuchi, Tomoharu; Kobayashi, Takayasu; Tamura, Shinri; Yokosawa, Hideyoshi

2006-08-07

ISG15, an interferon-upregulated ubiquitin-like protein, is covalently conjugated to various cellular proteins (ISGylation). In this study, we found that protein phosphatase 2Cbeta (PP2Cbeta), which functions in the nuclear factor kappaB (NF-kappaB) pathway via dephosphorylation of TGF-beta-activated kinase, was ISGylated, and analysis by NF-kappaB luciferase reporter assay revealed that PP2Cbeta activity was suppressed by co-expression of ISG15, UBE1L, and UbcH8. We determined the ISGylation sites of PP2Cbeta and constructed its ISGylation-resistant mutant. In contrast to the wild type, this mutant suppressed the NF-kappaB pathway even in the presence of ISG15, UBE1L, and UbcH8. Thus, we propose that ISGylation negatively regulates PP2Cbeta activity.

Distinct docking and stabilization steps of the Pseudopilus conformational transition path suggest rotational assembly of type IV pilus-like fibers.

PubMed

Nivaskumar, Mangayarkarasi; Bouvier, Guillaume; Campos, Manuel; Nadeau, Nathalie; Yu, Xiong; Egelman, Edward H; Nilges, Michael; Francetic, Olivera

2014-05-06

The closely related bacterial type II secretion (T2S) and type IV pilus (T4P) systems are sophisticated machines that assemble dynamic fibers promoting protein transport, motility, or adhesion. Despite their essential role in virulence, the molecular mechanisms underlying helical fiber assembly remain unknown. Here, we use electron microscopy and flexible modeling to study conformational changes of PulG pili assembled by the Klebsiella oxytoca T2SS. Neural network analysis of 3,900 pilus models suggested a transition path toward low-energy conformations driven by progressive increase in fiber helical twist. Detailed predictions of interprotomer contacts along this path were tested by site-directed mutagenesis, pilus assembly, and protein secretion analyses. We demonstrate that electrostatic interactions between adjacent protomers (P-P+1) in the membrane drive pseudopilin docking, while P-P+3 and P-P+4 contacts determine downstream fiber stabilization steps. These results support a model of a spool-like assembly mechanism for fibers of the T2SS-T4P superfamily. Copyright © 2014 Elsevier Ltd. All rights reserved.

Distinct docking and stabilization steps of the pseudopilus conformational transition path suggest rotational assembly of type IV pilus-like fibers

PubMed Central

Nivaskumar, Mangayarkarasi; Bouvier, Guillaume; Campos, Manuel; Nadeau, Nathalie; Yu, Xiong; Egelman, Edward H.; Nilges, Michael; Francetic, Olivera

2014-01-01

SUMMARY The closely related bacterial type II secretion (T2S) and type IV pilus (T4P) systems are sophisticated machines that assemble dynamic fibers promoting protein transport, motility or adhesion. Despite their essential role in virulence, the molecular mechanisms underlying helical fiber assembly remain unknown. Here we use electron microscopy and flexible modeling to study conformational changes of PulG pili assembled by the Klebsiella oxytoca T2SS. Neural network analysis of 3900 pilus models suggested a transition path towards low-energy conformations driven by progressive increase in fiber helical twist. Detailed predictions of inter-protomer contacts along this path were tested by site-directed mutagenesis, pilus assembly and protein secretion analyses. We demonstrate that electrostatic interactions between adjacent protomers (P-P+1) in the membrane drive pseudopilin docking, while P-P+3 and P-P+4 contacts determine downstream fiber stabilization steps. These results support a new model of a spool-like assembly mechanism for fibers of the T2SS-T4P superfamily. PMID:24685147

Single-cell transcriptomes identify human islet cell signatures and reveal cell-type–specific expression changes in type 2 diabetes

PubMed Central

Bolisetty, Mohan; Kursawe, Romy; Sun, Lili; Sivakamasundari, V.; Kycia, Ina

2017-01-01

Blood glucose levels are tightly controlled by the coordinated action of at least four cell types constituting pancreatic islets. Changes in the proportion and/or function of these cells are associated with genetic and molecular pathophysiology of monogenic, type 1, and type 2 (T2D) diabetes. Cellular heterogeneity impedes precise understanding of the molecular components of each islet cell type that govern islet (dys)function, particularly the less abundant delta and gamma/pancreatic polypeptide (PP) cells. Here, we report single-cell transcriptomes for 638 cells from nondiabetic (ND) and T2D human islet samples. Analyses of ND single-cell transcriptomes identified distinct alpha, beta, delta, and PP/gamma cell-type signatures. Genes linked to rare and common forms of islet dysfunction and diabetes were expressed in the delta and PP/gamma cell types. Moreover, this study revealed that delta cells specifically express receptors that receive and coordinate systemic cues from the leptin, ghrelin, and dopamine signaling pathways implicating them as integrators of central and peripheral metabolic signals into the pancreatic islet. Finally, single-cell transcriptome profiling revealed genes differentially regulated between T2D and ND alpha, beta, and delta cells that were undetectable in paired whole islet analyses. This study thus identifies fundamental cell-type–specific features of pancreatic islet (dys)function and provides a critical resource for comprehensive understanding of islet biology and diabetes pathogenesis. PMID:27864352

Diversification of non-visual photopigment parapinopsin in spectral sensitivity for diverse pineal functions.

PubMed

Koyanagi, Mitsumasa; Wada, Seiji; Kawano-Yamashita, Emi; Hara, Yuichiro; Kuraku, Shigehiro; Kosaka, Shigeaki; Kawakami, Koichi; Tamotsu, Satoshi; Tsukamoto, Hisao; Shichida, Yoshinori; Terakita, Akihisa

2015-09-15

Recent genome projects of various animals have uncovered an unexpectedly large number of opsin genes, which encode protein moieties of photoreceptor molecules, in most animals. In visual systems, the biological meanings of this diversification are clear; multiple types of visual opsins with different spectral sensitivities are responsible for color vision. However, the significance of the diversification of non-visual opsins remains uncertain, in spite of the importance of understanding the molecular mechanism and evolution of varied non-visual photoreceptions. Here, we investigated the diversification of the pineal photopigment parapinopsin, which serves as the UV-sensitive photopigment for the pineal wavelength discrimination in the lamprey, linking it with other pineal photoreception. Spectroscopic analyses of the recombinant pigments of the two teleost parapinopsins PP1 and PP2 revealed that PP1 is a UV-sensitive pigment, similar to lamprey parapinopsin, but PP2 is a blue-sensitive pigment, with an absorption maximum at 460-480 nm, showing the diversification of non-visual pigment with respect to spectral sensitivity. We also found that PP1 and PP2 exhibit mutually exclusive expressions in the pineal organs of three teleost species. By using transgenic zebrafish in which these parapinopsin-expressing cells are labeled, we found that PP1-expressing cells basically possess neuronal processes, which is consistent with their involvement in wavelength discrimination. Interestingly, however, PP2-expressing cells rarely possess neuronal processes, raising the possibility that PP2 could be involved in non-neural responses rather than neural responses. Furthermore, we found that PP2-expressing cells contain serotonin and aanat2, the key enzyme involved in melatonin synthesis from serotonin, whereas PP1-expressing cells do not contain either, suggesting that blue-sensitive PP2 is instead involved in light-regulation of melatonin secretion. In this paper, we have clearly shown the different molecular properties of duplicated non-visual opsins by demonstrating the diversification of parapinopsin with respect to spectral sensitivity. Moreover, we have shown a plausible link between the diversification and its physiological impact by discovering a strong candidate for the underlying pigment in light-regulated melatonin secretion in zebrafish; the diversification could generate a new contribution of parapinopsin to pineal photoreception. Current findings could also provide an opportunity to understand the "color" preference of non-visual photoreception.

Characterization of protein phosphatase 2A acting on phosphorylated plasma membrane aquaporin of tulip petals.

PubMed

Azad, Abul Kalam; Sawa, Yoshihiro; Ishikawa, Takahiro; Shibata, Hitoshi

2004-05-01

A protein phosphatase holo-type enzyme (38, 65, and 75 kDa) preparation and a free catalytic subunit (38 kDa) purified from tulip petals were characterized as protein phosphatase 2A (PP2A) by immunological and biochemical approaches. The plasma membrane containing the putative plasma membrane aquaporin (PM-AQP) was prepared from tulip petals, phosphorylated in vitro, and used as the substrate for both of the purified PP2A preparations. Although both preparations dephosphorylated the phosphorylated PM-AQP at 20 degrees C, only the holo-type enzyme preparation acted at 5 degrees C on the phosphorylated PM-AQP with higher substrate specificity, suggesting that regulatory subunits are required for low temperature-dependent dephosphorylation of PM-AQP in tulip petals.

Synthesis and coordinating ability of an anionic cobaltabisdicarbollide ligand geometrically analogous to BINAP.

PubMed

Rojo, Isabel; Teixidor, Francesc; Viñas, Clara; Kivekäs, Raikko; Sillanpää, Reijo

2004-10-25

The anionic chelating ligand [1,1'-(PPh2)2-3,3'-Co(1,2-C2B9H10)2]- has been synthesized from [3,3'-Co(1,2-C2B9H11)2]- in very good yield in a one-pot process with an easy work-up procedure. The coordinating ability of this ligand has been studied with Group 11 metal ions (Ag, Au) and with transition-metal ions (Pd, Rh). The two dicarbollide halves of the [1,1'-(PPh2)2-3,3'-Co(1,2-C2B9H10)2]- ligand can swing about one axis in a manner analogous to the constituent parts of BINAP and ferrocenyl phosphine derivatives. All these ligands function as hinges, with the most important property in relation to the coordination requirements of the metal being the PP distance. [1,1'-(PPh2)2-3,3'-Co(1,2-C2B9H10)2]-, BINAP, ferrocenyl phosphine derivatives, and other hinge ligands present a range of different PP separations, and consequently different coordination spheres and dispositions around metal cations. To account for these differences, the equation Dphi2 = D02 + 4 R2cos2(90-phi/2) has been developed. It relates the PP distance (Dphi) in a complex with the minimum PP distance (D0) that is characteristic of the hinge-type ligand.

PP2A activity is controlled by methylation and regulates oncoprotein expression in melanoma cells: a mechanism which participates in growth inhibition induced by chloroethylnitrosourea treatment.

PubMed

Guénin, Samuel; Schwartz, Laurent; Morvan, Daniel; Steyaert, Jean Marc; Poignet, Amandine; Madelmont, Jean Claude; Demidem, Aicha

2008-01-01

Protein phosphatase 2A (PP2A), an Akt pathway inhibitor, is considered to be activated by methylation of its catalytic subunit. Also PP2A downregulation was proposed to take part in carcinogenesis. Recently, PP2A activation was shown to be activated in response to DNA damage. To obtain further information on the role of PP2A in tumors and response to DNA damage, we investigated the relationship between PP2A methylation and activity, cell proliferation, Akt activation, c-Myc expression and PTEN activity in B16 melanoma cells untreated and after chloroethylnitrosourea (CENU) treatment. In untreated cells, okadaic acid, an antagonist of PP2A methylation, inhibited PP2A activity, stimulated cell proliferation, increased Akt activation and c-Myc expression. Xylulose-5-phosphate, an agonist of PP2A methylation, increased PP2A activity, decreased cell proliferation, Akt activation and c-Myc expression. However, both PP2A methylation modulators increased PTEN activity. During the response to CENU treatment, PP2A methylation and activity were strongly increased, Akt activation and c-Myc expression were decreased. However PTEN activity was increased. After tumor cell growth recovery, these modifications were moderately decreased. PP2A methylation was quantified and correlated positively with PP2A activity, and negatively with criteria for cell aggressiveness (cell proliferation, Akt activation, c-Myc expression). Based on these data, PP2A methylation status controls PP2A activity and oncoproteins expression and PP2A is strongly activated after CENU treatment thus partly explaining the growth inhibition in response to this agent. It follows that PP2A promethylating agents are potential candidates for anticancer drugs.

The Citrus ABA signalosome: identification and transcriptional regulation during sweet orange fruit ripening and leaf dehydration.

PubMed

Romero, Paco; Lafuente, María T; Rodrigo, María J

2012-08-01

The abscisic acid (ABA) signalling core in plants include the cytosolic ABA receptors (PYR/PYL/RCARs), the clade-A type 2C protein phosphatases (PP2CAs), and the subclass III SNF1-related protein kinases 2 (SnRK2s). The aim of this work was to identify these ABA perception system components in sweet orange and to determine the influence of endogenous ABA on their transcriptional regulation during fruit development and ripening, taking advantage of the comparative analysis between a wild-type and a fruit-specific ABA-deficient mutant. Transcriptional changes in the ABA signalosome during leaf dehydration were also studied. Six PYR/PYL/RCAR, five PP2CA, and two subclass III SnRK2 genes, homologous to those of Arabidopsis, were identified in the Citrus genome. The high degree of homology and conserved motifs for protein folding and for functional activity suggested that these Citrus proteins are bona fide core elements of ABA perception in orange. Opposite expression patterns of CsPYL4 and CsPYL5 and ABA accumulation were found during ripening, although there were few differences between varieties. In contrast, changes in expression of CsPP2CA genes during ripening paralleled those of ABA content and agreeed with the relevant differences between wild-type and mutant fruit transcript accumulation. CsSnRK2 gene expression continuously decreased with ripening and no remarkable differences were found between cultivars. Overall, dehydration had a minor effect on CsPYR/PYL/RCAR and CsSnRK2 expression in vegetative tissue, whereas CsABI1, CsAHG1, and CsAHG3 were highly induced by water stress. The global results suggest that responsiveness to ABA changes during citrus fruit ripening, and leaf dehydration was higher in the CsPP2CA gene negative regulators than in the other ABA signalosome components.

The Citrus ABA signalosome: identification and transcriptional regulation during sweet orange fruit ripening and leaf dehydration

PubMed Central

Rodrigo, María J.

2012-01-01

The abscisic acid (ABA) signalling core in plants include the cytosolic ABA receptors (PYR/PYL/RCARs), the clade-A type 2C protein phosphatases (PP2CAs), and the subclass III SNF1-related protein kinases 2 (SnRK2s). The aim of this work was to identify these ABA perception system components in sweet orange and to determine the influence of endogenous ABA on their transcriptional regulation during fruit development and ripening, taking advantage of the comparative analysis between a wild-type and a fruit-specific ABA-deficient mutant. Transcriptional changes in the ABA signalosome during leaf dehydration were also studied. Six PYR/PYL/RCAR, five PP2CA, and two subclass III SnRK2 genes, homologous to those of Arabidopsis, were identified in the Citrus genome. The high degree of homology and conserved motifs for protein folding and for functional activity suggested that these Citrus proteins are bona fide core elements of ABA perception in orange. Opposite expression patterns of CsPYL4 and CsPYL5 and ABA accumulation were found during ripening, although there were few differences between varieties. In contrast, changes in expression of CsPP2CA genes during ripening paralleled those of ABA content and agreeed with the relevant differences between wild-type and mutant fruit transcript accumulation. CsSnRK2 gene expression continuously decreased with ripening and no remarkable differences were found between cultivars. Overall, dehydration had a minor effect on CsPYR/PYL/RCAR and CsSnRK2 expression in vegetative tissue, whereas CsABI1, CsAHG1, and CsAHG3 were highly induced by water stress. The global results suggest that responsiveness to ABA changes during citrus fruit ripening, and leaf dehydration was higher in the CsPP2CA gene negative regulators than in the other ABA signalosome components. PMID:22888124

ABI1 and PP2CA Phosphatases Are Negative Regulators of Snf1-Related Protein Kinase1 Signaling in Arabidopsis[C][W

PubMed Central

Rodrigues, Américo; Adamo, Mattia; Crozet, Pierre; Margalha, Leonor; Confraria, Ana; Martinho, Cláudia; Elias, Alexandre; Rabissi, Agnese; Lumbreras, Victoria; González-Guzmán, Miguel; Antoni, Regina; Rodriguez, Pedro L.; Baena-González, Elena

2013-01-01

Plant survival under environmental stress requires the integration of multiple signaling pathways into a coordinated response, but the molecular mechanisms underlying this integration are poorly understood. Stress-derived energy deprivation activates the Snf1-related protein kinases1 (SnRK1s), triggering a vast transcriptional and metabolic reprogramming that restores homeostasis and promotes tolerance to adverse conditions. Here, we show that two clade A type 2C protein phosphatases (PP2Cs), established repressors of the abscisic acid (ABA) hormonal pathway, interact with the SnRK1 catalytic subunit causing its dephosphorylation and inactivation. Accordingly, SnRK1 repression is abrogated in double and quadruple pp2c knockout mutants, provoking, similarly to SnRK1 overexpression, sugar hypersensitivity during early seedling development. Reporter gene assays and SnRK1 target gene expression analyses further demonstrate that PP2C inhibition by ABA results in SnRK1 activation, promoting SnRK1 signaling during stress and once the energy deficit subsides. Consistent with this, SnRK1 and ABA induce largely overlapping transcriptional responses. Hence, the PP2C hub allows the coordinated activation of ABA and energy signaling, strengthening the stress response through the cooperation of two key and complementary pathways. PMID:24179127

Nitrous oxide for pneumoperitoneum: no laughing matter this! A prospective single blind case controlled study.

PubMed

Rammohan, Ashwin; Manimaran, A B; Manohar, R R; Naidu, R M

2011-01-01

The search for the perfect insufflating gas has been elusive. Even though Carbon dioxide (CO(2)) is the most commonly used gas, it has numerous cardiovascular, respiratory and hemodynamic side effects, which have often been taken for granted. In the current scenario of ever expanding and complex indications for Laparoscopic Surgery these changes have an increasing implication of placing the patient at risk. Nitrous Oxide (N(2)O) has now made a comeback and shown by recent studies to be as safe as CO(2) for creating pneumoperitoneum (PP). The purpose of our study is to determine whether benefits of N(2)O (PP) outweigh those of CO(2) PP in Laparoscopic Surgery. All patients undergoing Laparoscopic Surgery over an 8 week period were divided into two groups. Data were collected prospectively for Group I {N(2)O(n = 38)} and Group II {CO(2) PP(n = 39)}. Heart rate, Mean Arterial Blood Pressure, End-Tidal CO(2), Arterial pH, Peak Airway Pressure, Minute Ventilation and O(2) Saturation were recorded before PP, 15 minutes after PP and 10 minutes after exsufflation. Intraoperative anesthetic agent and postoperative pain medication use was recorded. Pain was assessed by means of visual analog scale (VAS) at postoperative hours 2 and 4 and on day 1. Results tabulated and analyzed statistically. There was no statistical difference in age, sex, weight, complexity of surgery (type of procedure and duration of PP), Anesthetic risk, and duration of hospitalization between the two groups. Mean End-Tidal CO(2) increase was greater despite a greater mean intraoperative increase in Minute Ventilation in group II, Heart Rate, Arterial pH, Mean Arterial Pressure under anesthesia were significantly higher in group II. The quantum of intraoperative anesthetic agent and postoperative pain (as assessed by Visual Analog Scale) was less in group I. This is an initial study assessing the use of N(2)O for insufflation; the results of our study suggest N(2)O PP has a definitive advantage over CO(2) PP. Further multicentric randomized trials are necessary before N(2)O becomes the standard insufflating agent. Copyright © 2010 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Performance of innovative textile biofilters for domestic wastewater treatment.

PubMed

Spychała, Marcin; Błazejewski, Ryszard; Nawrot, Tadeusz

2013-01-01

Two types of geotextile, TS 50 and TC/PP 300, were investigated as experimental filters. The raw wastewater, pre-treated in a septic tank, was intermittently dosed and filtered under hydrostatic pressure. At the beginning, the filter reactor comprised nine filters made of geotextiles (of three types: TS 10, TS 50 and TC/PP 300). At the end of the start-up period the TS 10 filters were removed due to their high outflow instability. After four months of working, the hydraulic capacities of the remaining filters were: 3.23 cm3/cm2/d for TS 50 and 4.14 cm3/cm2/d for TC/PP 300. The efficiencies of COD and BOD5 removal were similar for both types of geotextile (COD: 64%, BOD5: 80%). A small but statistically significant difference between ammonium nitrogen removal was observed (40% for TS 50 and 35% for TC/PP 300), most probably due to their different structure. Biological removal of P(tot) was relatively poor and similar for both geotextile types. The mean concentration of matter accumulated on the geotextiles was over one order of magnitude higher than conventional activated sludge concentrations. During the last weeks of the experiments the values of basic pollution indicators in the effluent were lower than the maximum permissible values (according to Polish law).

A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

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

Melcher, Karsten; Ng, Ley-Moy; Zhou, X Edward

2010-01-12

Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved β-loopsmore » that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling.« less

Aminolevulinic acid-mediated protoporphyrin IX and photodynamic therapy for breast cancers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Chen, Bin

2017-02-01

Photodynamic therapy (PDT) involves the combination of a photosensitizer and light of a specific wavelength. Upon light activation in the presence of oxygen, photosensitizer molecules generate reactive oxygen species that cause cytotoxicity by inducing oxidative stress. Aminolevulinic acid (ALA) is a pro-drug used for the diagnosis and PDT treatment of various solid tumors based on endogenous production of heme precursor protoporphyrin IX (PpIX). Although nearly all types of human cells express heme biosynthesis enzymes and produce PpIX, tumor cells are found to have more PpIX production and accumulation than normal cells, allowing for the detection and treatment of solid tumors. The objective of my research is to explore therapeutic approaches to enhance ALA-based tumor detection and therapy. We have found that high ABCG2 transporter activity in triple negative breast cancer cells (TNBC) contributed to reduced PpIX levels in cells, causing them to be more resistant towards ALA-PDT. The administration of an ABCG2 inhibitor, Ko143, was able to reverse cell resistance to ALA-PDT by enhancing PpIX mitochondrial accumulation and sensitizing cancer cells to ALA-PDT. Ko143 treatment had little effect on PpIX production and ALA-PDT in normal and ER- or HER2-positive cells. Furthermore, since some tyrosine kinase inhibitors (TKI) are known to block ABCG2 transporter activity, we screened a panel of tyrosine kinase inhibitors to examine its effect on enhancing PpIX fluorescence and ALA-PDT efficacy. Several TKIs including lapatinib and gefitinib showed effectiveness in increasing ALA-PpIX fluorescence in TNBC leading to increased cell death after PDT administration. These results indicate that inhibiting ABCG2 transporter using TKIs is a promising approach for targeting TNBC with ALA-based modality.

Functional characterization of a second pedal peptide/orcokinin‐type neuropeptide signaling system in the starfish Asterias rubens

PubMed Central

Lin, Ming; Egertová, Michaela; Zampronio, Cleidiane G.; Jones, Alexandra M.

2017-01-01

Abstract Molluscan pedal peptides (PPs) and arthropod orcokinins (OKs) are prototypes of a family of neuropeptides that have been identified in several phyla. Recently, starfish myorelaxant peptide (SMP) was identified as a PP/OK‐type neuropeptide in the starfish Patiria pectinifera (phylum Echinodermata). Furthermore, analysis of transcriptome sequence data from the starfish Asterias rubens revealed two PP/OK‐type precursors: an SMP‐type precursor (A. rubens PP‐like neuropeptide precursor 1; ArPPLNP1) and a second precursor (ArPPLNP2). We reported previously a detailed analysis of ArPPLNP1 expression in A. rubens and here we report the first functional characterization ArPPLNP2‐derived neuropeptides. Sequencing of a cDNA encoding ArPPLNP2 revealed that it comprises eleven related neuropeptides (ArPPLN2a‐k), the structures of several of which were confirmed using mass spectrometry. Analysis of the expression of ArPPLNP2 and neuropeptides derived from this precursor using mRNA in situ hybridization and immunohistochemistry revealed a widespread distribution, including expression in radial nerve cords, circumoral nerve ring, digestive system, tube feet and innervation of interossicular muscles. In vitro pharmacology revealed that the ArPPLNP2‐derived neuropeptide ArPPLN2h has no effect on the contractility of tube feet or the body wall‐associated apical muscle, contrasting with the relaxing effect of ArPPLN1b (ArSMP) on these preparations. ArPPLN2h does, however, cause dose‐dependent relaxation of cardiac stomach preparations, with greater potency/efficacy than ArPPLN1b and with similar potency/efficacy to the SALMFamide neuropeptide S2. In conclusion, there are similarities in the expression patterns of ArPPLNP1 and ArPPLNP2 but our data also indicate specialization in the roles of neuropeptides derived from these two PP/OK‐type precursors in starfish. PMID:29218721

Interactions of ABA signaling core components (SlPYLs, SlPP2Cs, and SlSnRK2s) in tomato (Solanum lycopersicon).

PubMed

Chen, Pei; Sun, Yu-Fei; Kai, Wen-Bin; Liang, Bin; Zhang, Yu-Shu; Zhai, Xia-Wan; Jiang, Li; Du, Yang-Wei; Leng, Ping

2016-10-20

Abscisic acid (ABA) regulates fruit development and ripening via its signaling. However, the exact role of ABA signaling core components in fruit have not yet been clarified. In this study, we investigated the potential interactions of tomato (Solanum lycopersicon) ABA signaling core components using yeast two-hybrid analysis, with or without ABA at different concentrations. The results showed that among 12 PYR/PYL/RCAR ABA receptors (SlPYLs), SlPYL1, SlPYL2, SlPYL4, SlPYL5, SlPYL 7, SlPYL8, SlPYL9, SlPYL10, SlPYL11, and SlPYL13 were ABA-dependent receptors, while SlPYL3 and SlPYL12 were ABA-independent receptors. Among five SlPP2Cs (type 2C protein phosphatases) and seven SlSnRK2s (subfamily 2 of SNF1-related kinases), all SlSnRK2s could interact with SlPP2C2, while SlSnRK2.8 also interacted with SlPP2C3. SlSnRK2.5 could interact with SlABF2/4 (ABA-responsive element binding factors). Expressions of SlPYL1, SlPYL2, SlPYL8, and SlPYL10 were upregulated under exogenous ABA but downregulated under nordihydroguaiaretic acid (NDGA) at the mature green stage of fruit ripening. The expressions of SlPP2C1, SlPP2C2, SlPP2C3, and SlPP2C5 were upregulated in ABA-treated fruit, but downregulated in NDGA-treated fruit at the mature green stage. The expressions of SlSnRK2.4, SlSnRK2.5, SlSnRK2.6, and SlSnRK2.7 were upregulated by ABA, but downregulated by NDGA. However, SlSnRK2.2 was down regulated by ABA. Expression of SlABF2/3/4 was enhanced by ABA but decreased by NDGA. Based on these results, we concluded that the majority of ABA receptor PYLs interact with SlPP2Cs in an ABA-dependent manner. SlPP2C2 and SlPP2C3 can interact with SlSnRK2s. SlSnRK2.5 could interact with SlABF2/4. Most ABA signaling core components respond to exogenous ABA. Copyright © 2016 Elsevier GmbH. All rights reserved.

Catalytic Subunit 1 of Protein Phosphatase 2A Is a Subunit of the STRIPAK Complex and Governs Fungal Sexual Development.

PubMed

Beier, Anna; Teichert, Ines; Krisp, Christoph; Wolters, Dirk A; Kück, Ulrich

2016-06-21

The generation of complex three-dimensional structures is a key developmental step for most eukaryotic organisms. The details of the molecular machinery controlling this step remain to be determined. An excellent model system to study this general process is the generation of three-dimensional fruiting bodies in filamentous fungi like Sordaria macrospora Fruiting body development is controlled by subunits of the highly conserved striatin-interacting phosphatase and kinase (STRIPAK) complex, which has been described in organisms ranging from yeasts to humans. The highly conserved heterotrimeric protein phosphatase PP2A is a subunit of STRIPAK. Here, catalytic subunit 1 of PP2A was functionally characterized. The Δpp2Ac1 strain is sterile, unable to undergo hyphal fusion, and devoid of ascogonial septation. Further, PP2Ac1, together with STRIPAK subunit PRO22, governs vegetative and stress-related growth. We revealed in vitro catalytic activity of wild-type PP2Ac1, and our in vivo analysis showed that inactive PP2Ac1 blocks the complementation of the sterile deletion strain. Tandem affinity purification, followed by mass spectrometry and yeast two-hybrid analysis, verified that PP2Ac1 is a subunit of STRIPAK. Further, these data indicate links between the STRIPAK complex and other developmental signaling pathways, implying the presence of a large interconnected signaling network that controls eukaryotic developmental processes. The insights gained in our study can be transferred to higher eukaryotes and will be important for understanding eukaryotic cellular development in general. The striatin-interacting phosphatase and kinase (STRIPAK) complex is highly conserved from yeasts to humans and is an important regulator of numerous eukaryotic developmental processes, such as cellular signaling and cell development. Although functional insights into the STRIPAK complex are accumulating, the detailed molecular mechanisms of single subunits are only partially understood. The first fungal STRIPAK was described in Sordaria macrospora, which is a well-established model organism used to study the formation of fungal fruiting bodies, three-dimensional organ-like structures. We analyzed STRIPAK subunit PP2Ac1, catalytic subunit 1 of protein phosphatase PP2A, to study the importance of the catalytic activity of this protein during sexual development. The results of our yeast two-hybrid analysis and tandem affinity purification, followed by mass spectrometry, indicate that PP2Ac1 activity connects STRIPAK with other signaling pathways and thus forms a large interconnected signaling network. Copyright © 2016 Beier et al.

Absence of ppGpp Leads to Increased Mobilization of Intermediately Accumulated Poly(3-Hydroxybutyrate) in Ralstonia eutropha H16

PubMed Central

Juengert, Janina R.; Borisova, Marina; Wolz, Christiane; Brigham, Christopher J.; Sinskey, Anthony J.

2017-01-01

ABSTRACT In this study, we constructed a set of Ralstonia eutropha H16 strains with single, double, or triple deletions of the (p)ppGpp synthase/hydrolase (spoT1), (p)ppGpp synthase (spoT2), and/or polyhydroxybutyrate (PHB) depolymerase (phaZa1 or phaZa3) gene, and we determined the impact on the levels of (p)ppGpp and on accumulated PHB. Mutants with deletions of both the spoT1 and spoT2 genes were unable to synthesize detectable amounts of (p)ppGpp and accumulated only minor amounts of PHB, due to PhaZa1-mediated depolymerization of PHB. In contrast, unusually high levels of PHB were found in strains in which the (p)ppGpp concentration was increased by the overexpression of (p)ppGpp synthase (SpoT2) and the absence of (p)ppGpp hydrolase. Determination of (p)ppGpp levels in wild-type R. eutropha under different growth conditions and induction of the stringent response by amino acid analogs showed that the concentrations of (p)ppGpp during the growth phase determine the amount of PHB remaining in later growth phases by influencing the efficiency of the PHB mobilization system in stationary growth. The data reported for a previously constructed ΔspoT2 strain (C. J. Brigham, D. R. Speth, C. Rha, and A. J. Sinskey, Appl Environ Microbiol 78:8033–8044, 2012, https://doi.org/10.1128/AEM.01693-12) were identified as due to an experimental error in strain construction, and our results are in contrast to the previous indication that the spoT2 gene product is essential for PHB accumulation in R. eutropha. IMPORTANCE Polyhydroxybutyrate (PHB) is an important intracellular carbon and energy storage compound in many prokaryotes and helps cells survive periods of starvation and other stress conditions. Research activities in several laboratories over the past 3 decades have shown that both PHB synthase and PHB depolymerase are constitutively expressed in most PHB-accumulating bacteria, such as Ralstonia eutropha. This implies that PHB synthase and depolymerase activities must be well regulated in order to avoid a futile cycle of simultaneous PHB synthesis and PHB degradation (mobilization). Previous reports suggested that the stringent response in Rhizobium etli and R. eutropha is involved in the regulation of PHB metabolism. However, the levels of (p)ppGpp and the influence of those levels on PHB accumulation and PHB mobilization have not yet been determined for any PHB-accumulating species. In this study, we optimized a (p)ppGpp extraction procedure and a high-performance liquid chromatography–mass spectrometry (HPLC-MS)-based detection method for the quantification of (p)ppGpp in R. eutropha. This enabled us to study the relationship between the concentrations of (p)ppGpp and the accumulated levels of PHB in the wild type and in several constructed mutant strains. We show that overproduction of the alarmone (p)ppGpp correlated with reduced growth and massive overproduction of PHB. In contrast, in the absence of (p)ppGpp, mobilization of PHB was dramatically enhanced. PMID:28455332

Effect of Placenta Previa on Preeclampsia

PubMed Central

Ying, Hao; Lu, Yi; Dong, Yi-Nuo; Wang, De-Fen

2016-01-01

Background The correlation between gestational hypertension-preeclampsia (GH-PE) and placenta previa (PP) is controversial. Specifically, it is unknown whether placenta previa has any effect on the various types of preeclampsia (PE), and the role PP with concurrent placenta accreta (PA) play in the occurrence of GH-PE are not well understood. Objective The aim of this study was to identify the effects of PP on GH, mild and severe preeclampsia (MPE and SPE), and early- and late-onset preeclampsia (EPE and LPE). Another aim of the study was to determine if concurrent PA impacts the relationship between PP and GH-PE. Methods A retrospective single-center study of 1,058 patients having singleton pregnancies with PP was performed, and 2,116 pregnant women were randomly included as controls. These cases were collected from a tertiary hospital and met the inclusion criteria for the study. Clinical information, including PP and the gestational age at the onset of GH-PE were collected. Binary and multiple logistic regression analyses were conducted after the confounding variables were controlled to assess the effects of PP on different types of GH-PE. Results There were 155 patients with GH-PE in the two groups. The incidences of GH-PE in the PP group and the control group were 2.5% (26/1058) and 6.1% (129/2116), respectively (P = 0.000). Binary and multiple regression analyses were conducted after controlling for confounding variables. Compared to the control group, in the PP group, the risk of GH-PE was reduced significantly by 78% (AOR: 0.216; 95% CI: 0.135–0.345); the risks of GH and PE were reduced by 55% (AOR: 0.451; 95% CI: 0.233–0.873) and 86% (AOR: 0.141; 95% CI: 0.073–0.271), respectively; the risks of MPE and SPE were reduced by 73% (AOR: 0.269; 95% CI: 0.087–0828) and 88% (AOR: 0.123; 95% CI: 0.055–0.279), respectively; and the risks of EPE and LPE were reduced by 95% (AOR: 0.047; 95% CI: 0.012–0.190) and 67% (AOR: 0.330; 95% CI: 0.153–0.715), respectively. The incidence of concurrent PA in women with PP was 5.86%; PP with PA did not significantly further reduce the incidence of GH-PE compared with PP without PA (1.64% vs. 2.51%, P>0.05). Binary logistic regression analyses were conducted after controlling for confounding variables, compared with the non-PP + GH-PE group, and the AOR of FGR in the non-PP + non-GH-PE group was 0.206 (0.124–0.342). Compared with the PP + GH-PE group, the AOR of FGR in the PP + non-GH-PE group was 0.430 (0.123–1.500). Conclusion PP is not only associated with a significant reduction in the incidence of GH-PE, but also is associated with a reduction in incidence of various types of PE. Concurrent PA and PP do not show association with a reduction in incidence of GH-PE. PMID:26731265

Protein phosphatase 2Cm is a critical regulator of branched-chain amino acid catabolism in mice and cultured cells.

PubMed

Lu, Gang; Sun, Haipeng; She, Pengxiang; Youn, Ji-Youn; Warburton, Sarah; Ping, Peipei; Vondriska, Thomas M; Cai, Hua; Lynch, Christopher J; Wang, Yibin

2009-06-01

The branched-chain amino acids (BCAA) are essential amino acids required for protein homeostasis, energy balance, and nutrient signaling. In individuals with deficiencies in BCAA, these amino acids can be preserved through inhibition of the branched-chain-alpha-ketoacid dehydrogenase (BCKD) complex, the rate-limiting step in their metabolism. BCKD is inhibited by phosphorylation of its E1alpha subunit at Ser293, which is catalyzed by BCKD kinase. During BCAA excess, phosphorylated Ser293 (pSer293) becomes dephosphorylated through the concerted inhibition of BCKD kinase and the activity of an unknown intramitochondrial phosphatase. Using unbiased, proteomic approaches, we have found that a mitochondrial-targeted phosphatase, PP2Cm, specifically binds the BCKD complex and induces dephosphorylation of Ser293 in the presence of BCKD substrates. Loss of PP2Cm completely abolished substrate-induced E1alpha dephosphorylation both in vitro and in vivo. PP2Cm-deficient mice exhibited BCAA catabolic defects and a metabolic phenotype similar to the intermittent or intermediate types of human maple syrup urine disease (MSUD), a hereditary disorder caused by defects in BCKD activity. These results indicate that PP2Cm is the endogenous BCKD phosphatase required for nutrient-mediated regulation of BCKD activity and suggest that defects in PP2Cm may be responsible for a subset of human MSUD.

Development and Experimental Operation of a Flashboard Plasma Cathode Test Stand

DTIC Science & Technology

2012-06-01

grid-controlled system [31]. J.R. Bayless and his group developed a new type of plasma cathode electron gun qualified for pulsed and continuous...Interferometry of flashboard and cable- gun plasma opening switches on hawk,” IEEE Trans. Plasma Sci., vol. 25, no. 2, pp. 189–195, Apr. 1997. [29] C...The plasma -cathode electron gun ,” IEEE Journal of Quantum Electronics, vol. 10, no. 2, pp. 213–218, Feb 1974. [33] Ady Hershcovitch

Arabidopsis PHOSPHOTYROSYL PHOSPHATASE ACTIVATOR Is Essential for PROTEIN PHOSPHATASE 2A Holoenzyme Assembly and Plays Important Roles in Hormone Signaling, Salt Stress Response, and Plant Development1[W][OPEN

PubMed Central

Chen, Jian; Hu, Rongbin; Zhu, Yinfeng; Shen, Guoxin; Zhang, Hong

2014-01-01

PROTEIN PHOSPHATASE 2A (PP2A) is a major group of serine/threonine protein phosphatases in eukaryotes. It is composed of three subunits: scaffolding subunit A, regulatory subunit B, and catalytic subunit C. Assembly of the PP2A holoenzyme in Arabidopsis (Arabidopsis thaliana) depends on Arabidopsis PHOSPHOTYROSYL PHOSPHATASE ACTIVATOR (AtPTPA). Reduced expression of AtPTPA leads to severe defects in plant development, altered responses to abscisic acid, ethylene, and sodium chloride, and decreased PP2A activity. In particular, AtPTPA deficiency leads to decreased methylation in PP2A-C subunits (PP2Ac). Complete loss of PP2Ac methylation in the suppressor of brassinosteroid insensitive1 mutant leads to 30% reduction of PP2A activity, suggesting that PP2A with a methylated C subunit is more active than PP2A with an unmethylated C subunit. Like AtPTPA, PP2A-A subunits are also required for PP2Ac methylation. The interaction between AtPTPA and PP2Ac is A subunit dependent. In addition, AtPTPA deficiency leads to reduced interactions of B subunits with C subunits, resulting in reduced functional PP2A holoenzyme formation. Thus, AtPTPA is a critical factor for committing the subunit A/subunit C dimer toward PP2A heterotrimer formation. PMID:25281708

Microvascular dysfunction with increased vascular leakage response in mice systemically exposed to arsenic.

PubMed

Chen, Shih-Chieh; Huang, Shin-Yin; Lu, Chi-Yu; Hsu, Ya-Hung; Wang, Dean-Chuan

2014-09-01

The mechanisms underlying cardiovascular disease induced by arsenic exposure are not completely understood. The objectives of this study were to investigate whether arsenic-fed mice have an increased vascular leakage response to vasoactive agents and whether enhanced type-2 protein phosphatase (PP2A) activity is involved in mustard oil-induced leakage. ICR mice were fed water or sodium arsenite (20 mg/kg) for 4 or 8 weeks. The leakage response to vasoactive agents was quantified using the Evans blue (EB) technique or vascular labeling with carbon particles. Increased EB leakage and high density of carbon-labeled microvessels were detected in arsenic-fed mice treated with mustard oil. Histamine induced significantly higher vascular leakage in arsenic-fed mice than in water-fed mice. Pretreatment with the PP2A inhibitor okadaic acid or the neurokinin 1 receptor (NK1R) blocker RP67580 significantly reduced mustard oil-induced vascular leakage in arsenic-fed mice. The protein levels of PP2Ac and NK1R were similar in both groups. PP2A activity was significantly higher in the arsenic-fed mice compared with the control group. These findings indicate that microvessels generally respond to vasoactive agents, and that the increased PP2A activity is involved in mustard oil-induced vascular leakage in arsenic-fed mice. Arsenic may initiate endothelial dysfunction, resulting in vascular leakage in response to vasoactive agents.

In vitro extinction learning in Hermissenda: involvement of conditioned inhibition molecules

PubMed Central

Cavallo, Joel S.; Hamilton, Brittany N.; Farley, Joseph

2014-01-01

Extinction of a conditioned association is typically viewed as the establishment of new learning rather than the erasure of the original memory. However, recent research in the nudibranch, Hermissenda crassicornis (H.c.) demonstrated that extinction training (using repeated light-alone presentations) given 15 min, but not 23 h, after memory acquisition reversed both the cellular correlates of learning (enhanced Type B cell excitability) and the behavioral changes (reduced phototaxis) produced by associative conditioning (pairings of light, CS, and rotation, US). Here, we investigated the putative molecular signaling pathways that underlie this extinction in H.c. by using a novel in vitro protocol combined with pharmacological manipulations. After intact H.c. received either light-rotation pairings (Paired), random presentations of light and rotation (Random), or no stimulation (Untrained), B cells from isolated CNSs were recorded from during exposure to extinction training consisting of two series of 15 consecutive light-steps (LSs). When in vitro extinction was administered shortly (2 h, but not 24 h) after paired training, B cells from Paired animals showed progressive and robust declines in spike frequency by the 30th LS, while control cells (Random and Untrained) did not. We found that several molecules implicated in H.c. conditioned inhibitory (CI) learning, protein phosphatase 1 (PP1) and arachidonic acid (AA)/12-lipoxygenase (12-LOX) metabolites, also contributed to the spike frequency decreases produced by in vitro extinction. Protein phosphatase 2B (PP2B) also appeared to play a role. Calyculin A (PP1 inhibitor), cyclosporin A (PP2B inhibitor), and baicalein (a 12-LOX inhibitor) all blocked the spike frequency declines in Paired B cells produced by 30 LSs. Conversely, injection of catalytically-active PP1 (caPP1) or PP2B (caPP2B) into Untrained B cells partially mimicked the spike frequency declines observed in Paired cells, as did bath-applied AA, and occluded additional LS-produced reductions in spiking in Paired cells. PMID:25374517

PP2A(Cdc55)'s role in reductional chromosome segregation during achiasmate meiosis in budding yeast is independent of its FEAR function.

PubMed

Kerr, Gary W; Wong, Jin Huei; Arumugam, Prakash

2016-07-26

PP2A(Cdc55) is a highly conserved serine-threonine protein phosphatase that is involved in diverse cellular processes. In budding yeast, meiotic cells lacking PP2A(Cdc55) activity undergo a premature exit from meiosis I which results in a failure to form bipolar spindles and divide nuclei. This defect is largely due to its role in negatively regulating the Cdc Fourteen Early Anaphase Release (FEAR) pathway. PP2A(Cdc55) prevents nucleolar release of the Cdk (Cyclin-dependent kinase)-antagonising phosphatase Cdc14 by counteracting phosphorylation of the nucleolar protein Net1 by Cdk. CDC55 was identified in a genetic screen for monopolins performed by isolating suppressors of spo11Δ spo12Δ lethality suggesting that Cdc55 might have a role in meiotic chromosome segregation. We investigated this possibility by isolating cdc55 alleles that suppress spo11Δ spo12Δ lethality and show that this suppression is independent of PP2A(Cdc55)'s FEAR function. Although the suppressor mutations in cdc55 affect reductional chromosome segregation in the absence of recombination, they have no effect on chromosome segregation during wild type meiosis. We suggest that Cdc55 is required for reductional chromosome segregation during achiasmate meiosis and this is independent of its FEAR function.

B′-protein phosphatase 2A is a functional binding partner of delta-retroviral integrase

PubMed Central

Maertens, Goedele N.

2016-01-01

To establish infection, a retrovirus must insert a DNA copy of its RNA genome into host chromatin. This reaction is catalysed by the virally encoded enzyme integrase (IN) and is facilitated by viral genus-specific host factors. Herein, cellular serine/threonine protein phosphatase 2A (PP2A) is identified as a functional IN binding partner exclusive to δ-retroviruses, including human T cell lymphotropic virus type 1 and 2 (HTLV-1 and HTLV-2) and bovine leukaemia virus (BLV). PP2A is a heterotrimer composed of a scaffold, catalytic and one of any of four families of regulatory subunits, and the interaction is specific to the B′ family of the regulatory subunits. B′-PP2A and HTLV-1 IN display nuclear co-localization, and the B′ subunit stimulates concerted strand transfer activity of δ-retroviral INs in vitro. The protein–protein interaction interface maps to a patch of highly conserved residues on B′, which when mutated render B′ incapable of binding to and stimulating HTLV-1 and -2 IN strand transfer activity. PMID:26657642

Phosphorylation-dependent autoinhibition of myosin light chain phosphatase accounts for Ca2+ sensitization force of smooth muscle contraction.

PubMed

Khromov, Alexander; Choudhury, Nandini; Stevenson, Andra S; Somlyo, Avril V; Eto, Masumi

2009-08-07

The reversible regulation of myosin light chain phosphatase (MLCP) in response to agonist stimulation and cAMP/cGMP signals plays an important role in the regulation of smooth muscle (SM) tone. Here, we investigated the mechanism underlying the inhibition of MLCP induced by the phosphorylation of myosin phosphatase targeting subunit (MYPT1), a regulatory subunit of MLCP, at Thr-696 and Thr-853 using glutathione S-transferase (GST)-MYPT1 fragments having the inhibitory phosphorylation sites. GST-MYPT1 fragments, including only Thr-696 and only Thr-853, inhibited purified MLCP (IC(50) = 1.6 and 60 nm, respectively) when they were phosphorylated with RhoA-dependent kinase (ROCK). The activities of isolated catalytic subunits of type 1 and type 2A phosphatases (PP1 and PP2A) were insensitive to either fragment. Phospho-GST-MYPT1 fragments docked directly at the active site of MLCP, and this was blocked by a PP1/PP2A inhibitor microcystin (MC)-LR or by mutation of the active sites in PP1. GST-MYPT1 fragments induced a contraction of beta-escin-permeabilized ileum SM at constant pCa 6.3 (EC(50) = 2 microm), which was eliminated by Ala substitution of the fragment at Thr-696 or by ROCK inhibitors or 8Br-cGMP. GST-MYPT1-(697-880) was 5-times less potent than fragments including Thr-696. Relaxation induced by 8Br-cGMP was not affected by Ala substitution at Ser-695, a known phosphorylation site for protein kinase A/G. Thus, GST-MYPT1 fragments are phosphorylated by ROCK in permeabilized SM and mimic agonist-induced inhibition and cGMP-induced activation of MLCP. We propose a model in which MYPT1 phosphorylation at Thr-696 and Thr-853 causes an autoinhibition of MLCP that accounts for Ca(2+) sensitization of smooth muscle force.

Overexpression of a novel Arabidopsis PP2C isoform, AtPP2CF1, enhances plant biomass production by increasing inflorescence stem growth

PubMed Central

Sugimoto, Hiroki; Kondo, Satoshi; Tanaka, Tomoko; Imamura, Chie; Muramoto, Nobuhiko; Hattori, Etsuko; Ogawa, Ken’ichi; Mitsukawa, Norihiro; Ohto, Chikara

2014-01-01

In contrast to mammals, higher plants have evolved to express diverse protein phosphatase 2Cs (PP2Cs). Of all Arabidopsis thaliana PP2Cs, members of PP2C subfamily A, including ABI1, have been shown to be key negative regulators of abscisic acid (ABA) signalling pathways, which regulate plant growth and development as well as tolerance to adverse environmental conditions. However, little is known about the enzymatic and signalling roles of other PP2C subfamilies. Here, we report a novel Arabidopsis subfamily E PP2C gene, At3g05640, designated AtPP2CF1. AtPP2CF1 was dramatically expressed in response to exogenous ABA and was expressed in vascular tissues and guard cells, similar to most subfamily A PP2C genes. In vitro enzymatic activity assays showed that AtPP2CF1 possessed functional PP2C activity. However, yeast two-hybrid analysis revealed that AtPP2CF1 did not interact with PYR/PYL/RCAR receptors or three SnRK2 kinases, which are ABI1-interacting proteins. This was supported by homology-based structural modelling demonstrating that the putative active- and substrate-binding site of AtPP2CF1 differed from that of ABI1. Furthermore, while overexpression of ABI1 in plants induced an ABA-insensitive phenotype, Arabidopsis plants overexpressing AtPP2CF1 (AtPP2CF1oe) were weakly hypersensitive to ABA during seed germination and drought stress. Unexpectedly, AtPP2CF1oe plants also exhibited increased biomass yield, mainly due to accelerated growth of inflorescence stems through the activation of cell proliferation and expansion. Our results provide new insights into the physiological significance of AtPP2CF1 as a candidate gene for plant growth production and for potential application in the sustainable supply of plant biomass. PMID:25038254

Multilevel Control of Arabidopsis 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase by Protein Phosphatase 2A[W

PubMed Central

Leivar, Pablo; Antolín-Llovera, Meritxell; Ferrero, Sergi; Closa, Marta; Arró, Montserrat; Ferrer, Albert; Boronat, Albert; Campos, Narciso

2011-01-01

Plants synthesize a myriad of isoprenoid products that are required both for essential constitutive processes and for adaptive responses to the environment. The enzyme 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes a key regulatory step of the mevalonate pathway for isoprenoid biosynthesis and is modulated by many endogenous and external stimuli. In spite of that, no protein factor interacting with and regulating plant HMGR in vivo has been described so far. Here, we report the identification of two B′′ regulatory subunits of protein phosphatase 2A (PP2A), designated B′′α and B′′β, that interact with HMGR1S and HMGR1L, the major isoforms of Arabidopsis thaliana HMGR. B′′α and B′′β are Ca2+ binding proteins of the EF-hand type. We show that HMGR transcript, protein, and activity levels are modulated by PP2A in Arabidopsis. When seedlings are transferred to salt-containing medium, B′′α and PP2A mediate the decrease and subsequent increase of HMGR activity, which results from a steady rise of HMGR1-encoding transcript levels and an initial sharper reduction of HMGR protein level. In unchallenged plants, PP2A is a posttranslational negative regulator of HMGR activity with the participation of B′′β. Our data indicate that PP2A exerts multilevel control on HMGR through the five-member B′′ protein family during normal development and in response to a variety of stress conditions. PMID:21478440

Structural basis of PP2A activation by PTPA, an ATP-dependent activation chaperone

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

Guo, Feng; Stanevich, Vitali; Wlodarchak, Nathan

Proper activation of protein phosphatase 2A (PP2A) catalytic subunit is central for the complex PP2A regulation and is crucial for broad aspects of cellular function. The crystal structure of PP2A bound to PP2A phosphatase activator (PTPA) and ATPγS reveals that PTPA makes broad contacts with the structural elements surrounding the PP2A active site and the adenine moiety of ATP. PTPA-binding stabilizes the protein fold of apo-PP2A required for activation, and orients ATP phosphoryl groups to bind directly to the PP2A active site. This allows ATP to modulate the metal-binding preferences of the PP2A active site and utilize the PP2A activemore » site for ATP hydrolysis. In vitro, ATP selectively and drastically enhances binding of endogenous catalytic metal ions, which requires ATP hydrolysis and is crucial for acquisition of pSer/Thr-specific phosphatase activity. Furthermore, both PP2A- and ATP-binding are required for PTPA function in cell proliferation and survival. Our results suggest novel mechanisms of PTPA in PP2A activation with structural economy and a unique ATP-binding pocket that could potentially serve as a specific therapeutic target.« less

Release of GTP Exchange Factor Mediated Down-Regulation of Abscisic Acid Signal Transduction through ABA-Induced Rapid Degradation of RopGEFs

PubMed Central

Waadt, Rainer; Schroeder, Julian I.

2016-01-01

The phytohormone abscisic acid (ABA) is critical to plant development and stress responses. Abiotic stress triggers an ABA signal transduction cascade, which is comprised of the core components PYL/RCAR ABA receptors, PP2C-type protein phosphatases, and protein kinases. Small GTPases of the ROP/RAC family act as negative regulators of ABA signal transduction. However, the mechanisms by which ABA controls the behavior of ROP/RACs have remained unclear. Here, we show that an Arabidopsis guanine nucleotide exchange factor protein RopGEF1 is rapidly sequestered to intracellular particles in response to ABA. GFP-RopGEF1 is sequestered via the endosome-prevacuolar compartment pathway and is degraded. RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1. Interestingly, RopGEF1 undergoes constitutive degradation in pp2c quadruple abi1/abi2/hab1/pp2ca mutant plants, revealing that active PP2C protein phosphatases protect and stabilize RopGEF1 from ABA-mediated degradation. Interestingly, ABA-mediated degradation of RopGEF1 also plays an important role in ABA-mediated inhibition of lateral root growth. The presented findings point to a PP2C-RopGEF-ROP/RAC control loop model that is proposed to aid in shutting off ABA signal transduction, to counteract leaky ABA signal transduction caused by “monomeric” PYL/RCAR ABA receptors in the absence of stress, and facilitate signaling in response to ABA. PMID:27192441

Hyperphosphorylation of PP2A in colorectal cancer and the potential therapeutic value showed by its forskolin-induced dephosphorylation and activation.

PubMed

Cristóbal, Ion; Rincón, Raúl; Manso, Rebeca; Madoz-Gúrpide, Juan; Caramés, Cristina; del Puerto-Nevado, Laura; Rojo, Federico; García-Foncillas, Jesús

2014-09-01

The tumor suppressor protein phosphatase 2A (PP2A) is frequently inactivated in human cancer and phosphorylation of its catalytic subunit (p-PP2A-C) at tyrosine-307 (Y307) has been described to inhibit this phosphatase. However, its molecular and clinical relevance in colorectal cancer (CRC) remains unclear. p-PP2A-C Y307 was determined by immunoblotting in 7 CRC cell lines and 35 CRC patients. CRC cells were treated with the PP2A activator forskolin alone or combined with the PP2A inhibitor okadaic acid, 5-fluorouracil and oxaliplatin. We examined cell growth, colonosphere formation, caspase activity and AKT and ERK activation. PP2A-C was found hyperphosphorylated in CRC cell lines. Forskolin dephosphorylated and activated PP2A, impairing proliferation and colonosphere formation, and inducing activation of caspase 3/7 and changes in AKT and ERK phosphorylation. Moreover, forskolin showed additive effects with 5-fluorouracil and oxaliplatin treatments. Analysis of p-PP2A-C Y307 in primary tumors confirmed the presence of this alteration in a subgroup of CRC patients. Our data show that PP2A-C hyperphosphorylation is a frequent event that contributes to PP2A inhibition in CRC. Antitumoral effects of forskolin-mediated PP2A activation suggest that the analysis of p-PP2A-C Y307 status could be used to identify a subgroup of patients who would benefit from treatments based on PP2A activators. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis, stability range and characterization of Pr2Cu2O5

NASA Astrophysics Data System (ADS)

Fernández-Sanjulián, Javier; Morán, Emilio; Ángel Alario-Franco, Miguel

2010-03-01

A novel Pr2Cu2O5 phase has been prepared under high-pressure and high-temperature conditions (P ∼6 GPa and T ∼1673 K) in a Belt-type apparatus and characterized by X-ray diffraction and electron microscopy. The crystal structure appears to be an orthorhombic "oxygen-deficient perovskite" (M.T. Anderson, J.T. Vaughey, and K.R. Poeppelmeier, Structural similarities among oxygen-deficient perovskites, Chem. Mater. 5 (1993), pp. 151-165) isostructural with La2Cu2O5 (J.F. Bringley, B.A. Scott, S.J. La Placa, R.F. Boheme, T.M. Shaw, M.W. McElfresh, S.S. Trail, and D.E. Cox, Synthesis of the defect perovskite series LaCuO 3-δ with copper valence varying from 2+to 3+, Nature 347 (1990), pp. 263-265) and Nd2Cu2O5 (B.-H. Chen, D. Walker, E. Suard, B.A. Scott, B. Mercey, M. Hervieu, and B. Raveau, High pressure synthesis of NdCuO3-δ perovskites (0≤δ≤0.5). Inorg. Chem. 34 (1995), pp. 2077-2083).

Serum GGT activity and hsCRP level in patients with type 2 diabetes mellitus with good and poor glycemic control: An evidence linking oxidative stress, inflammation and glycemic control.

PubMed

Gohel, Mukesh G; Chacko, Anusha N

2013-12-20

Diabetes is undoubtedly one of the most challenging health problems in 21st century. Understanding the pathogenesis and preventing long term complications have been major goals of research in diabetes mellitus (DM). Research in the past few years has linked oxidative stress and inflammation to beta cell dysfunction. Aim of this study is to evaluate serum gamma-glutamyl transferase (GGT) activity (marker of oxidative stress) and high sensitivity C reactive protein (hsCRP) level (an inflammatory marker) in type 2 DM subjects with good and poor glycemic control. Further, we investigated correlation between serum GGT and hsCRP level with glycemic control (FBS, PP2BS, HbA1c) in subjects. A cross sectional study consists of 150 patients out of them 50 patients having type 2 DM with good control (Group II), 50 patients with type 2 DM with poor control (Group III) and 50 normal healthy control (Group I) were selected. Serum GGT, serum hsCRP, FBS, PP2BS, HbA1c, and other biochemical investigations include serum liver enzymes and lipids were measured. Mean serum GGT and hsCRP concentration were statistically significantly higher in group III patients compared to group I and group II subjects as well as increased in group II compared to group I (p < 0.001). Further significant positive correlation was observed between GGT and hsCRP concentration as well as both with HbA1c, FBS, and PP2BS. Oxidative stress and inflammation appears to be a key component and also associated with poor glycemic control and further pathogenesis of diabetes and its complications. All our finding suggesting a link between oxidative stress, inflammation and glycemic control in patient with type 2 diabetes mellitus.

Basal protein phosphatase 2A activity restrains cytokine expression: role for MAPKs and tristetraprolin.

PubMed

Rahman, Md Mostafizur; Rumzhum, Nowshin N; Morris, Jonathan C; Clark, Andrew R; Verrills, Nicole M; Ammit, Alaina J

2015-05-18

PP2A is a master controller of multiple inflammatory signaling pathways. It is a target in asthma; however the molecular mechanisms by which PP2A controls inflammation warrant further investigation. In A549 lung epithelial cells in vitro we show that inhibition of basal PP2A activity by okadaic acid (OA) releases restraint on MAPKs and thereby increases MAPK-mediated pro-asthmatic cytokines, including IL-6 and IL-8. Notably, PP2A inhibition also impacts on the anti-inflammatory protein - tristetraprolin (TTP), a destabilizing RNA binding protein regulated at multiple levels by p38 MAPK. Although PP2A inhibition increases TTP mRNA expression, resultant TTP protein builds up in the hyperphosphorylated inactive form. Thus, when PP2A activity is repressed, pro-inflammatory cytokines increase and anti-inflammatory proteins are rendered inactive. Importantly, these effects can be reversed by the PP2A activators FTY720 and AAL(s), or more specifically by overexpression of the PP2A catalytic subunit (PP2A-C). Moreover, PP2A plays an important role in cytokine expression in cells stimulated with TNFα; as inhibition of PP2A with OA or PP2A-C siRNA results in significant increases in cytokine production. Collectively, these data reveal the molecular mechanisms of PP2A regulation and highlight the potential of boosting the power of endogenous phosphatases as novel anti-inflammatory strategies to combat asthmatic inflammation.

Phosphatidic acid (PA) binds PP2AA1 to regulate PP2A activity and PIN1 polar localization.

PubMed

Gao, Hong-Bo; Chu, Yu-Jia; Xue, Hong-Wei

2013-09-01

Phospholipase D (PLD) exerts broad biological functions in eukaryotes through regulating downstream effectors by its product, phosphatidic acid (PA). Protein kinases and phosphatases, such as mammalian target of rapamycin (mTOR), Protein Phosphatase 1 (PP1) and Protein Phosphatase 2C (PP2C), are PA-binding proteins that execute crucial regulatory functions in both animals and plants. PA participates in many signaling pathways by modulating the enzymatic activity and/or subcellular localization of bound proteins. In this study, we demonstrated that PLD-derived PA interacts with the scaffolding A1 subunit of Protein Phosphatase 2A (PP2A) and regulates PP2A-mediated PIN1 dephosphorylation in Arabidopsis. Genetic and pharmacological studies showed that both PA and PP2A participate in the regulation of auxin distribution. In addition, both the phosphorylation status and polar localization of PIN1 protein were affected by PLD inhibitors. Exogenous PA triggered the membrane accumulation of PP2AA1 and enhanced the PP2A activity at membrane, while PLD inhibition resulted in the reduced endosomal localization and perinuclear aggregation of PP2AA1. These results demonstrate the important role of PLD-derived PA in normal PP2A-mediated PIN dephosphorylation and reveal a novel mechanism, in which PA recruits PP2AA1 to the membrane system and regulates PP2A function on membrane-targeted proteins. As PA and PP2A are conserved among eukaryotes, other organisms might use similar mechanisms to mediate multiple biological processes.

Free Fatty Acid-Induced PP2A Hyperactivity Selectively Impairs Hepatic Insulin Action on Glucose Metabolism

PubMed Central

Galbo, Thomas; Olsen, Grith Skytte; Quistorff, Bjørn; Nishimura, Erica

2011-01-01

In type 2 Diabetes (T2D) free fatty acids (FFAs) in plasma are increased and hepatic insulin resistance is “selective”, in the sense that the insulin-mediated decrease of glucose production is blunted while insulin's effect on stimulating lipogenesis is maintained. We investigated the molecular mechanisms underlying this pathogenic paradox. Primary rat hepatocytes were exposed to palmitate for twenty hours. To establish the physiological relevance of the in vitro findings, we also studied insulin-resistant Zucker Diabetic Fatty (ZDF) rats. While insulin-receptor phosphorylation was unaffected, activation of Akt and inactivation of the downstream targets Glycogen synthase kinase 3α (Gsk3α and Forkhead box O1 (FoxO1) was inhibited in palmitate-exposed cells. Accordingly, dose-response curves for insulin-mediated suppression of the FoxO1-induced gluconeogenic genes and for de novo glucose production were right shifted, and insulin-stimulated glucose oxidation and glycogen synthesis were impaired. In contrast, similar to findings in human T2D, the ability of insulin to induce triglyceride (TG) accumulation and transcription of the enzymes that catalyze de novo lipogenesis and TG assembly was unaffected. Insulin-induction of these genes could, however, be blocked by inhibition of the atypical PKCs (aPKCs). The activity of the Akt-inactivating Protein Phosphatase 2A (PP2A) was increased in the insulin-resistant cells. Furthermore, inhibition of PP2A by specific inhibitors increased insulin-stimulated activation of Akt and phosphorylation of FoxO1 and Gsk3α. Finally, PP2A mRNA levels were increased in liver, muscle and adipose tissue, while PP2A activity was increased in liver and muscle tissue in insulin-resistant ZDF rats. In conclusion, our findings indicate that FFAs may cause a selective impairment of insulin action upon hepatic glucose metabolism by increasing PP2A activity. PMID:22087313

Menstrual hygiene management among adolescent girls in India: a systematic review and meta-analysis.

PubMed

van Eijk, Anna Maria; Sivakami, M; Thakkar, Mamita Bora; Bauman, Ashley; Laserson, Kayla F; Coates, Susanne; Phillips-Howard, Penelope A

2016-03-02

To assess the status of menstrual hygiene management (MHM) among adolescent girls in India to determine unmet needs. Systematic review and meta-analysis. We searched PubMed, The Global Health Database, Google Scholar and references for studies published from 2000 to September 2015 on girls' MHM. India. Adolescent girls. Information on menarche awareness, type of absorbent used, disposal, hygiene, restrictions and school absenteeism was extracted from eligible materials; a quality score was applied. Meta-analysis was used to estimate pooled prevalence (PP), and meta-regression to examine the effect of setting, region and time. Data from 138 studies involving 193 subpopulations and 97,070 girls were extracted. In 88 studies, half of the girls reported being informed prior to menarche (PP 48%, 95% CI 43% to 53%, I(2) 98.6%). Commercial pad use was more common among urban (PP 67%, 57% to 76%, I(2) 99.3%, n=38) than rural girls (PP 32%, 25% to 38%, I(2) 98.6%, n=56, p<0.0001), with use increasing over time (p<0.0001). Inappropriate disposal was common (PP 23%, 16% to 31%, I(2) 99.0%, n=34). Menstruating girls experienced many restrictions, especially for religious activities (PP 0.77, 0.71 to 0.83, I(2) 99.1%, n=67). A quarter (PP 24%, 19% to 30%, I(2) 98.5%, n=64) reported missing school during periods. A lower prevalence of absenteeism was associated with higher commercial pad use in univariate (p=0.023) but not in multivariate analysis when adjusted for region (p=0.232, n=53). Approximately a third of girls changed their absorbents in school facilities (PP 37%, 29% to 46%, I(2) 97.8%, n=17). Half of the girls' homes had a toilet (PP 51%, 36% to 67%, I(2) 99.4%, n=21). The quality of studies imposed limitations on analyses and the interpretation of results (mean score 3 on a scale of 0-7). Strengthening of MHM programmes in India is needed. Education on awareness, access to hygienic absorbents and disposal of MHM items need to be addressed. CRD42015019197. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Analysis of the interactome of the Ser/Thr Protein Phosphatase type 1 in Plasmodium falciparum.

PubMed

Hollin, Thomas; De Witte, Caroline; Lenne, Astrid; Pierrot, Christine; Khalife, Jamal

2016-03-17

Protein Phosphatase 1 (PP1) is an enzyme essential to cell viability in the malaria parasite Plasmodium falciparum (Pf). The activity of PP1 is regulated by the binding of regulatory subunits, of which there are up to 200 in humans, but only 3 have been so far reported for the parasite. To better understand the P. falciparum PP1 (PfPP1) regulatory network, we here report the use of three strategies to characterize the PfPP1 interactome: co-affinity purified proteins identified by mass spectrometry, yeast two-hybrid (Y2H) screening and in silico analysis of the P. falciparum predicted proteome. Co-affinity purification followed by MS analysis identified 6 PfPP1 interacting proteins (Pips) of which 3 contained the RVxF consensus binding, 2 with a Fxx[RK]x[RK] motif, also shown to be a PP1 binding motif and one with both binding motifs. The Y2H screens identified 134 proteins of which 30 present the RVxF binding motif and 20 have the Fxx[RK]x[RK] binding motif. The in silico screen of the Pf predicted proteome using a consensus RVxF motif as template revealed the presence of 55 potential Pips. As further demonstration, 35 candidate proteins were validated as PfPP1 interacting proteins in an ELISA-based assay. To the best of our knowledge, this is the first study on PfPP1 interactome. The data reports several conserved PP1 interacting proteins as well as a high number of specific interactors to PfPP1. Their analysis indicates a high diversity of biological functions for PP1 in Plasmodium. Based on the present data and on an earlier study of the Pf interactome, a potential implication of Pips in protein folding/proteolysis, transcription and pathogenicity networks is proposed. The present work provides a starting point for further studies on the structural basis of these interactions and their functions in P. falciparum.

PP2A regulates kinetochore-microtubule attachment during meiosis I in oocyte.

PubMed

Tang, An; Shi, Peiliang; Song, Anying; Zou, Dayuan; Zhou, Yue; Gu, Pengyu; Huang, Zan; Wang, Qinghua; Lin, Zhaoyu; Gao, Xiang

2016-06-02

Studies using in vitro cultured oocytes have indicated that the protein phosphatase 2A (PP2A), a major serine/threonine protein phosphatase, participates in multiple steps of meiosis. Details of oocyte maturation regulation by PP2A remain unclear and an in vivo model can provide more convincing information. Here, we inactivated PP2A by mutating genes encoding for its catalytic subunits (PP2Acs) in mouse oocytes. We found that eliminating both PP2Acs caused female infertility. Oocytes lacking PP2Acs failed to complete 1(st) meiotic division due to chromosome misalignment and abnormal spindle assembly. In mitosis, PP2A counteracts Aurora kinase B/C (AurkB/C) to facilitate correct kinetochore-microtubule (KT-MT) attachment. In meiosis I in oocyte, we found that PP2Ac deficiency destabilized KT-MT attachments. Chemical inhibition of AurkB/C in PP2Ac-null oocytes partly restored the formation of lateral/merotelic KT-MT attachments but not correct KT-MT attachments. Taken together, our findings demonstrate that PP2Acs are essential for chromosome alignments and regulate the formation of correct KT-MT attachments in meiosis I in oocytes.

Menstrual hygiene management among adolescent girls in India: a systematic review and meta-analysis

PubMed Central

van Eijk, Anna Maria; Sivakami, M; Thakkar, Mamita Bora; Bauman, Ashley; Laserson, Kayla F; Coates, Susanne; Phillips-Howard, Penelope A

2016-01-01

Objectives To assess the status of menstrual hygiene management (MHM) among adolescent girls in India to determine unmet needs. Design Systematic review and meta-analysis. We searched PubMed, The Global Health Database, Google Scholar and references for studies published from 2000 to September 2015 on girls’ MHM. Setting India. Participants Adolescent girls. Outcome measures Information on menarche awareness, type of absorbent used, disposal, hygiene, restrictions and school absenteeism was extracted from eligible materials; a quality score was applied. Meta-analysis was used to estimate pooled prevalence (PP), and meta-regression to examine the effect of setting, region and time. Results Data from 138 studies involving 193 subpopulations and 97 070 girls were extracted. In 88 studies, half of the girls reported being informed prior to menarche (PP 48%, 95% CI 43% to 53%, I2 98.6%). Commercial pad use was more common among urban (PP 67%, 57% to 76%, I2 99.3%, n=38) than rural girls (PP 32%, 25% to 38%, I2 98.6%, n=56, p<0.0001), with use increasing over time (p<0.0001). Inappropriate disposal was common (PP 23%, 16% to 31%, I2 99.0%, n=34). Menstruating girls experienced many restrictions, especially for religious activities (PP 0.77, 0.71 to 0.83, I2 99.1%, n=67). A quarter (PP 24%, 19% to 30%, I2 98.5%, n=64) reported missing school during periods. A lower prevalence of absenteeism was associated with higher commercial pad use in univariate (p=0.023) but not in multivariate analysis when adjusted for region (p=0.232, n=53). Approximately a third of girls changed their absorbents in school facilities (PP 37%, 29% to 46%, I2 97.8%, n=17). Half of the girls’ homes had a toilet (PP 51%, 36% to 67%, I2 99.4%, n=21). The quality of studies imposed limitations on analyses and the interpretation of results (mean score 3 on a scale of 0–7). Conclusions Strengthening of MHM programmes in India is needed. Education on awareness, access to hygienic absorbents and disposal of MHM items need to be addressed. Trial registration number CRD42015019197. PMID:26936906

Overexpression of a novel Arabidopsis PP2C isoform, AtPP2CF1, enhances plant biomass production by increasing inflorescence stem growth.

PubMed

Sugimoto, Hiroki; Kondo, Satoshi; Tanaka, Tomoko; Imamura, Chie; Muramoto, Nobuhiko; Hattori, Etsuko; Ogawa, Ken'ichi; Mitsukawa, Norihiro; Ohto, Chikara

2014-10-01

In contrast to mammals, higher plants have evolved to express diverse protein phosphatase 2Cs (PP2Cs). Of all Arabidopsis thaliana PP2Cs, members of PP2C subfamily A, including ABI1, have been shown to be key negative regulators of abscisic acid (ABA) signalling pathways, which regulate plant growth and development as well as tolerance to adverse environmental conditions. However, little is known about the enzymatic and signalling roles of other PP2C subfamilies. Here, we report a novel Arabidopsis subfamily E PP2C gene, At3g05640, designated AtPP2CF1. AtPP2CF1 was dramatically expressed in response to exogenous ABA and was expressed in vascular tissues and guard cells, similar to most subfamily A PP2C genes. In vitro enzymatic activity assays showed that AtPP2CF1 possessed functional PP2C activity. However, yeast two-hybrid analysis revealed that AtPP2CF1 did not interact with PYR/PYL/RCAR receptors or three SnRK2 kinases, which are ABI1-interacting proteins. This was supported by homology-based structural modelling demonstrating that the putative active- and substrate-binding site of AtPP2CF1 differed from that of ABI1. Furthermore, while overexpression of ABI1 in plants induced an ABA-insensitive phenotype, Arabidopsis plants overexpressing AtPP2CF1 (AtPP2CF1oe) were weakly hypersensitive to ABA during seed germination and drought stress. Unexpectedly, AtPP2CF1oe plants also exhibited increased biomass yield, mainly due to accelerated growth of inflorescence stems through the activation of cell proliferation and expansion. Our results provide new insights into the physiological significance of AtPP2CF1 as a candidate gene for plant growth production and for potential application in the sustainable supply of plant biomass. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The Neurospora crassa PP2A Regulatory Subunits RGB1 and B56 Are Required for Proper Growth and Development and Interact with the NDR Kinase COT1

PubMed Central

Shomin-Levi, Hila; Yarden, Oded

2017-01-01

COT1 is the founding member of the highly conserved nuclear Dbf2-related (NDR) Ser/Thr kinase family and plays a role in the regulation of polar growth and development in Neurospora crassa and other fungi. Changes in COT1 phosphorylation state have been shown to affect hyphal elongation, branching, and conidiation. The function of NDR protein kinases has been shown to be regulated by type 2A protein phosphatases (PP2As). PP2As are heterotrimers comprised of a catalytic and scaffolding protein along with an interchangeable regulatory subunit involved in determining substrate specificity. Inactivation of the N. crassa PP2A regulatory subunits rgb-1 and b56 conferred severe hyphal growth defects. Partial suppression of defects observed in the rgb-1RIP strain (but not in the Δb56 mutant) was observed in cot-1 phosphomimetic mutants, demonstrating that altering COT1 phosphorylation state can bypass, at least in part, the requirement of a functional RGB1 subunit. The functional fusion proteins RGB1::GFP and B56::GFP predominantly localized to hyphal tips and septa, respectively, indicating that their primary activity is in different cellular locations. COT1 protein forms exhibited a hyperphosphorylated gel migration pattern in an rgb-1RIP mutant background, similar to that observed when the fungus was cultured in the presence of the PP2A inhibitor cantharidin. COT1 was hypophosphorylated in a Δb56 mutant background, suggesting that this regulatory subunit may be involved in determining COT1 phosphorylation state, yet in an indirect manner. Reciprocal co-immunoprecipitation analyses, using tagged COT1, PPH1, RGB1, and B56 subunits established that these proteins physically interact. Taken together, our data determine the presence of a functional and physical link between PP2A and COT1 and show that two of the PP2A regulatory subunits interact with the kinase and determine COT1 phosphorylation state. PMID:28928725

Live imaging of companion cells and sieve elements in Arabidopsis leaves.

PubMed

Cayla, Thibaud; Batailler, Brigitte; Le Hir, Rozenn; Revers, Frédéric; Anstead, James A; Thompson, Gary A; Grandjean, Olivier; Dinant, Sylvie

2015-01-01

The phloem is a complex tissue composed of highly specialized cells with unique subcellular structures and a compact organization that is challenging to study in vivo at cellular resolution. We used confocal scanning laser microscopy and subcellular fluorescent markers in companion cells and sieve elements, for live imaging of the phloem in Arabidopsis leaves. This approach provided a simple framework for identifying phloem cell types unambiguously. It highlighted the compactness of the meshed network of organelles within companion cells. By contrast, within the sieve elements, unknown bodies were observed in association with the PP2-A1:GFP, GFP:RTM1 and RTM2:GFP markers at the cell periphery. The phloem lectin PP2-A1:GFP marker was found in the parietal ground matrix. Its location differed from that of the P-protein filaments, which were visualized with SEOR1:GFP and SEOR2:GFP. PP2-A1:GFP surrounded two types of bodies, one of which was identified as mitochondria. This location suggested that it was embedded within the sieve element clamps, specific structures that may fix the organelles to each another or to the plasma membrane in the sieve tubes. GFP:RTM1 was associated with a class of larger bodies, potentially corresponding to plastids. PP2-A1:GFP was soluble in the cytosol of immature sieve elements. The changes in its subcellular localization during differentiation provide an in vivo blueprint for monitoring this process. The subcellular features obtained with these companion cell and sieve element markers can be used as landmarks for exploring the organization and dynamics of phloem cells in vivo.

Live Imaging of Companion Cells and Sieve Elements in Arabidopsis Leaves

PubMed Central

Cayla, Thibaud; Batailler, Brigitte; Le Hir, Rozenn; Revers, Frédéric; Anstead, James A.; Thompson, Gary A.; Grandjean, Olivier; Dinant, Sylvie

2015-01-01

The phloem is a complex tissue composed of highly specialized cells with unique subcellular structures and a compact organization that is challenging to study in vivo at cellular resolution. We used confocal scanning laser microscopy and subcellular fluorescent markers in companion cells and sieve elements, for live imaging of the phloem in Arabidopsis leaves. This approach provided a simple framework for identifying phloem cell types unambiguously. It highlighted the compactness of the meshed network of organelles within companion cells. By contrast, within the sieve elements, unknown bodies were observed in association with the PP2-A1:GFP, GFP:RTM1 and RTM2:GFP markers at the cell periphery. The phloem lectin PP2-A1:GFP marker was found in the parietal ground matrix. Its location differed from that of the P-protein filaments, which were visualized with SEOR1:GFP and SEOR2:GFP. PP2-A1:GFP surrounded two types of bodies, one of which was identified as mitochondria. This location suggested that it was embedded within the sieve element clamps, specific structures that may fix the organelles to each another or to the plasma membrane in the sieve tubes. GFP:RTM1 was associated with a class of larger bodies, potentially corresponding to plastids. PP2-A1:GFP was soluble in the cytosol of immature sieve elements. The changes in its subcellular localization during differentiation provide an in vivo blueprint for monitoring this process. The subcellular features obtained with these companion cell and sieve element markers can be used as landmarks for exploring the organization and dynamics of phloem cells in vivo. PMID:25714357

Inflammatory stimuli promote growth and invasion of pancreatic cancer cells through NF-κB pathway dependent repression of PP2Ac

PubMed Central

Tao, Min; Liu, Lu; Shen, Meng; Zhi, Qiaoming; Gong, Fei-Ran; Zhou, Binhua P.; Wu, Yadi; Liu, Haiyan; Chen, Kai; Shen, Bairong; Wu, Meng-Yao; Shou, Liu-Mei; Li, Wei

2016-01-01

ABSTRACT Previous studies have indicated that inflammatory stimulation represses protein phosphatase 2A (PP2A), a well-known tumor suppressor. However, whether PP2A repression participates in pancreatic cancer progression has not been verified. We used lipopolysaccharide (LPS) and macrophage-conditioned medium (MCM) to establish in vitro inflammation models, and investigated whether inflammatory stimuli affect pancreatic cancer cell growth and invasion PP2A catalytic subunit (PP2Ac)-dependently. Via nude mouse models of orthotopic tumor xenografts and dibutyltin dichloride (DBTC)-induced chronic pancreatitis, we evaluated the effect of an inflammatory microenvironment on PP2Ac expression in vivo. We cloned the PP2Acα and PP2Acβ isoform promoters to investigate the PP2Ac transcriptional regulation mechanisms. MCM accelerated pancreatic cancer cell growth; MCM and LPS promoted cell invasion. DBTC promoted xenograft growth and metastasis, induced tumor-associated macrophage infiltration, promoted angiogenesis, activated the nuclear factor-κB (NF-κB) pathway, and repressed PP2Ac expression. In vitro, LPS and MCM downregulated PP2Ac mRNA and protein. PP2Acα overexpression attenuated JNK, ERK, PKC, and IKK phosphorylation, and impaired LPS/MCM-stimulated cell invasion and MCM-promoted cell growth. LPS and MCM activated the NF-κB pathway in vitro. LPS and MCM induced IKK and IκB phosphorylation, leading to p65/RelA nuclear translocation and transcriptional activation. Overexpression of the dominant negative forms of IKKα attenuated LPS and MCM downregulation of PP2Ac, suggesting inflammatory stimuli repress PP2Ac expression NF-κB pathway–dependently. Luciferase reporter gene assay verified that LPS and MCM downregulated PP2Ac transcription through an NF-κB–dependent pathway. Our study presents a new mechanism in inflammation-driven cancer progression through NF-κB pathway–dependent PP2Ac repression. PMID:26761431

AtPP2CG1, a protein phosphatase 2C, positively regulates salt tolerance of Arabidopsis in abscisic acid-dependent manner

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

Liu, Xin, E-mail: fangfei6073@126.com; Zhu, Yanming, E-mail: ymzhu2001@neau.edu.cn; Zhai, Hong, E-mail: Zhai.h@neigaehrb.ac.cn

2012-06-15

Highlights: Black-Right-Pointing-Pointer AtPP2CG1 positively regulates salt tolerance in ABA-dependent manner. Black-Right-Pointing-Pointer AtPP2CG1 up-regulates the expression of marker genes in different pathways. Black-Right-Pointing-Pointer AtPP2CG1 expresses in the vascular system and trichomes of Arabidopsis. -- Abstract: AtPP2CG1 (Arabidopsis thaliana protein phosphatase 2C G Group 1) was predicted as an abiotic stress candidate gene by bioinformatic analysis in our previous study. The gene encodes a putative protein phosphatase 2C that belongs to Group G of PP2C. There is no report of Group G genes involved in abiotic stress so far. Real-time RT-PCR analysis showed that AtPP2CG1 expression was induced by salt, drought, andmore » abscisic acid (ABA) treatment. The expression levels of AtPP2CG1 in the ABA synthesis-deficient mutant abi2-3 were much lower than that in WT plants under salt stress suggesting that the expression of AtPP2CG1 acts in an ABA-dependent manner. Over-expression of AtPP2CG1 led to enhanced salt tolerance, whereas its loss of function caused decreased salt tolerance. These results indicate that AtPP2CG1 positively regulates salt stress in an ABA-dependent manner. Under salt treatment, AtPP2CG1 up-regulated the expression levels of stress-responsive genes, including RD29A, RD29B, DREB2A and KIN1. GUS activity was detected in roots, leaves, stems, flower, and trichomes of AtPP2CG1 promoter-GUS transgenic plants. AtPP2CG1 protein was localized in nucleus and cytoplasm via AtPP2CG1:eGFP and YFP:AtPP2CG1 fusion approaches.« less

Methods for Identifying Object Class, Type, and Orientation in the Presence of Uncertainty

DTIC Science & Technology

1990-08-01

on Range Finding Techniques for Computer Vision," IEEE Trans. on Pattern Analysis and Machine Intellegence PAMI-5 (2), pp 129-139 March 1983. 15. Yang... Artificial Intelligence Applications, pp 199-205, December 1984. 16. Flynn, P.J. and Jain, A.K.," On Reliable Curvature Estimation, " Proceedings of the

Abscisic acid affects transcription of chloroplast genes via protein phosphatase 2C-dependent activation of nuclear genes: repression by guanosine-3'-5'-bisdiphosphate and activation by sigma factor 5.

PubMed

Yamburenko, Maria V; Zubo, Yan O; Börner, Thomas

2015-06-01

Abscisic acid (ABA) represses the transcriptional activity of chloroplast genes (determined by run-on assays), with the exception of psbD and a few other genes in wild-type Arabidopsis seedlings and mature rosette leaves. Abscisic acid does not influence chloroplast transcription in the mutant lines abi1-1 and abi2-1 with constitutive protein phosphatase 2C (PP2C) activity, suggesting that ABA affects chloroplast gene activity by binding to the pyrabactin resistance (PYR)/PYR1-like or regulatory component of ABA receptor protein family (PYR/PYL/RCAR) and signaling via PP2Cs and sucrose non-fermenting protein-related kinases 2 (SnRK2s). Further we show by quantitative PCR that ABA enhances the transcript levels of RSH2, RSH3, PTF1 and SIG5. RelA/SpoT homolog 2 (RSH2) and RSH3 are known to synthesize guanosine-3'-5'-bisdiphosphate (ppGpp), an inhibitor of the plastid-gene-encoded chloroplast RNA polymerase. We propose, therefore, that ABA leads to an inhibition of chloroplast gene expression via stimulation of ppGpp synthesis. On the other hand, sigma factor 5 (SIG5) and plastid transcription factor 1 (PTF1) are known to be necessary for the transcription of psbD from a specific light- and stress-induced promoter (the blue light responsive promoter, BLRP). We demonstrate that ABA activates the psbD gene by stimulation of transcription initiation at BLRP. Taken together, our data suggest that ABA affects the transcription of chloroplast genes by a PP2C-dependent activation of nuclear genes encoding proteins involved in chloroplast transcription. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Restricted Protein Phosphatase 2A Targeting by Merkel Cell Polyomavirus Small T Antigen

PubMed Central

Kwun, Hyun Jin; Shuda, Masahiro; Camacho, Carlos J.; Gamper, Armin M.; Thant, Mamie; Chang, Yuan

2015-01-01

ABSTRACT Merkel cell polyomavirus (MCV) is a newly discovered human cancer virus encoding a small T (sT) oncoprotein. We performed MCV sT FLAG-affinity purification followed by mass spectroscopy (MS) analysis, which identified several protein phosphatases (PP), including PP2A A and C subunits and PP4C, as potential cellular interacting proteins. PP2A targeting is critical for the transforming properties of nonhuman polyomaviruses, such as simian virus 40 (SV40), but is not required for MCV sT-induced rodent cell transformation. We compared similarities and differences in PP2A binding between MCV and SV40 sT. While SV40 sT coimmunopurified with subunits PP2A Aα and PP2A C, MCV sT coimmunopurified with PP2A Aα, PP2A Aβ, and PP2A C. Scanning alanine mutagenesis at 29 sites across the MCV sT protein revealed that PP2A-binding domains lie on the opposite molecular surface from a previously described large T stabilization domain (LSD) loop that binds E3 ligases, such as Fbw7. MCV sT-PP2A interactions can be functionally distinguished by mutagenesis from MCV sT LSD-dependent 4E-BP1 hyperphosphorylation and viral DNA replication enhancement. MCV sT has a restricted range for PP2A B subunit substitution, inhibiting only the assembly of B56α into the phosphatase holoenzyme. In contrast, SV40 sT inhibits the assembly of B55α, B56α and B56ε into PP2A. We conclude that MCV sT is required for Merkel cell carcinoma growth, but its in vitro transforming activity depends on LSD interactions rather than PP2A targeting. IMPORTANCE Merkel cell polyomavirus is a newly discovered human cancer virus that promotes cancer, in part, through expression of its small T (sT) oncoprotein. Animal polyomavirus sT oncoproteins have been found to cause experimental tumors by blocking the activities of a group of phosphatases called protein phosphatase 2A (PP2A). Our structural analysis reveals that MCV sT also displaces the B subunit of PP2A to inhibit PP2A activity. MCV sT, however, only displaces a restricted subset of PP2A B subunits, which is insufficient to cause tumor cell formation in vitro. MCV sT instead transforms tumor cells through another region called the large T stabilization domain. The PP2A targeting and transforming activities lie on opposite faces of the MCV sT molecule and can be genetically separated from each other. PMID:25631078

Tuneable reactivity with PPh3 and SnX2 of four- and five-coordinate Pd(II) and Pt(II) complexes containing polyphosphines.

PubMed

Fernández-Anca, Damián; García-Seijo, M Inés; García-Fernández, M Esther

2013-07-28

The reactivity of the unusual d(8) trigonal-bipyramidal systems [MX(PP3)]X (X = Cl: M = Pd(1a), Pt(2a); X = Br: M = Pd(3a), Pt(4a); X = I: M = Pd(5a), Pt(6a); PP3 = tris[2-(diphenylphosphino)ethyl]phosphine) in CHCl3-CH3OH, the square-pyramidal compounds [MCl(NP3)]Cl (M = Pd(7a); Pt(8a); NP3 = tris[2-(diphenylphosphino)ethyl]amine) in CD3OD-DMF and the distorted square-planar mononuclear [MX(PNP)]X (M = Pd: X = Cl(10a); M = Pt: X = I(10b); PNP = bis[2-(diphenylphosphino)ethyl]amine) and the heteronuclear [PdAu2X4(PP3)] [X = I(9a), Cl(14a), Br(15a)] and [MAuX2(PP3)]X [M = Pd: X = Cl(16a); M = Pt: X = Cl(17a), Br(18a)] species in CDCl3 with PPh3 + SnX2 has been explored to establish the factors that influence the nature of the products. With the mononuclear precursors the course of the reaction is strongly dependent on the tripodal or linear arrangement of the polydentate ligand and in the former case on the halogen. Thus, while for chlorides (1a-2a, 7a-8a) and bromides (3a-4a) the reaction led to the trigonal-bipyramidal compounds [M(SnCl3)(AP3)][SnCl3] [A = P: M = Pd(1), Pt(2); A = N: M = Pd(7), Pt(8)], [MBr(PP3)][SnBr3] [M = Pd(4), Pt(6)] containing M-Sn and M-Br bonds, respectively, for iodides (5a-6a) resulted in the unknown neutral square-planar compounds [MI2(PP(PO)2)(SnI2)2] [M = Pd(9) and Pt(10)] bearing two dangling P=O-SnI2 units and P2MI2 environments. However, complexes of the type [PtCl(PP2PO)X]X' [X = SnCl2, X' = [SnCl3](-)(11)] and [M(PP(PO)2)2X4]X'2 [X = SnCl2, X' = [SnCl3](-): M = Pd(12), Pt(13)] showing P=O-SnCl2 arms were obtained by direct reaction of [PtCl(PP2PO)]Cl (11a) and [M(PP(PO)2)2]Cl2 [M = Pd(12a), Pt(13a)] with SnCl2 in CH3OH. Although complex 9 was also prepared by interaction of the heteronuclear iodide 9a with PPh3 + SnI2 in CDCl3, the use of the neutral and ionic heteronuclear chlorides and bromides (14a-18a) as starting materials afforded the distorted square-planar ionic systems [MAuX'(PP3)(PPh3)][SnX3]2 [M = Pd: X = Cl, X' = SnCl3(-)(14); X = Br, X' = SnBr3(-)(15); M = Pt: X = Cl, X' = SnCl3(-)(17); X = Br, X' = SnBr3(-)(18)] containing M-SnX3 and P-Au-PPh3 functionalities. It was found that these reactions where the heteronuclear species are the precursors proceed via the trigonal-bipyramidal halides not only with X = Cl and Br(1a-4a) but also I(5a). When the precursors were 10a and 10b the reaction occurred with formation of [Pd(PNP)(PPh3)][SnCl3]2 (23) and [Pt(PNP)(PPh3)][SnCl2I]2 (24) showing M-PPh3 units and trihalostannato counter anions.

Study of Protein Phosphatase 2A (PP2A) Activity in LPS-Induced Tolerance Using Fluorescence-Based and Immunoprecipitation-Aided Methodology.

PubMed

Sun, Lei; Ii, Adlai L Pappy; Pham, Tiffany T; Shanley, Thomas P

2015-06-29

Protein phosphatase 2A (PP2A) is one of the most abundant intracellular serine/threonine (Ser/Thr) phosphatases accounting for 1% of the total cellular protein content. PP2A is comprised of a heterodimeric core enzyme and a substrate-specific regulatory subunit. Potentially, at least seventy different compositions of PP2A exist because of variable regulatory subunit binding that accounts for various activity modulating numerous cell functions. Due to the constitutive phosphatase activity present inside cells, a sensitive assay is required to detect the changes of PP2A activity under various experimental conditions. We optimized a fluorescence assay (DIFMU assay) by combining it with prior anti-PP2A immunoprecipitation to quantify PP2A-specific phosphatase activity. It is also known that prior exposure to lipopolysaccharides (LPS) induces "immune tolerance" of the cells to subsequent stimulation. Herein we report that PP2A activity is upregulated in tolerized peritoneal macrophages, corresponding to decreased TNF-α secretion upon second LPS stimulation. We further examined the role of PP2A in the tolerance effect by using PP2ACαl°xl°x;lyM-Cre conditional knockout macrophages. We found that PP2A phosphatase activity cannot be further increased by tolerance. TNF-α secretion from tolerized PP2ACαl°xl°x;lyM-Cre macrophages is higher than tolerized control macrophages. Furthermore, we showed that the increased TNF-α secretion may be due to an epigenetic transcriptionally active signature on the promoter of TNF-α gene rather than regulation of the NFκB/IκB signaling pathway. These results suggest a role for increased PP2A activity in the regulation of immune tolerance.

Aralkyl selenoglycosides and related selenosugars in acetylated form activate protein phosphatase-1 and -2A.

PubMed

Kónya, Zoltán; Bécsi, Bálint; Kiss, Andrea; Tamás, István; Lontay, Beáta; Szilágyi, László; Kövér, Katalin E; Erdődi, Ferenc

2018-05-01

Aralkyl and aryl selenoglycosides as well as glycosyl selenocarboxylate derivatives were assayed on the activity of protein phosphatase-1 (PP1) and -2A (PP2A) catalytic subunits (PP1c and PP2Ac) in search of compounds for PP1c and PP2Ac effectors. The majority of tested selenoglycosides activated both PP1c and PP2Ac by ∼2-4-fold in a phosphatase assay with phosphorylated myosin light chain substrate when the hydroxyl groups of the glycosyl moiety were acetylated, but they were without any effects in the non-acetylated forms. A peptide from the myosin phosphatase target subunit-1 (MYPT1 23-38 ) that included an RVxF PP1c-binding motif attenuated activation of PP1c by 2-Trifluoromethylbenzyl 2,3,4,6-tetra-O-acetyl-1-seleno-β-d-glucopyranoside (TFM-BASG) and 4-Bromobenzyl 2,3,4,6-tetra-O-acetyl-1-seleno-β-d-glucopyranoside (Br-BASG). MYPT1 23-38 stimulated PP2Ac and contributed to PP2Ac activation exerted by either Br-BASG or TFM-BASG. Br-BASG and TFM-BASG suppressed partially binding of PP1c to MYPT1 in surface plasmon resonance based binding experiments. Molecular docking predicted that the hydrophobic binding surfaces in PP1c for interaction with either the RVxF residues of PP1c-interactors or selenoglycosides are partially overlapped. Br-BASG and TFM-BASG caused a moderate increase in the phosphatase activity of HeLa cells in 1 h, and suppressed cell viability in 24 h incubations. In conclusion, our present study identified selenoglycosides as novel activators of PP1 and PP2A as well as provided insights into the structural background of their interactions establishing a molecular model for future design of more efficient phosphatase activator molecules. Copyright © 2018 Elsevier Ltd. All rights reserved.

A novel regulatory defect in the branched-chain α-keto acid dehydrogenase complex due to a mutation in the PPM1K gene causes a mild variant phenotype of maple syrup urine disease.

PubMed

Oyarzabal, Alfonso; Martínez-Pardo, Mercedes; Merinero, Begoña; Navarrete, Rosa; Desviat, Lourdes R; Ugarte, Magdalena; Rodríguez-Pombo, Pilar

2013-02-01

This article describes a hitherto unreported involvement of the phosphatase PP2Cm, a recently described member of the branched-chain α-keto acid dehydrogenase (BCKDH) complex, in maple syrup urine disease (MSUD). The disease-causing mutation was identified in a patient with a mild variant phenotype, involving a gene not previously associated with MSUD. SNP array-based genotyping showed a copy-neutral homozygous pattern for chromosome 4 compatible with uniparental isodisomy. Mutation analysis of the candidate gene, PPM1K, revealed a homozygous c.417_418delTA change predicted to result in a truncated, unstable protein. No PP2Cm mutant protein was detected in immunocytochemical or Western blot expression analyses. The transient expression of wild-type PPM1K in PP2Cm-deficient fibroblasts recovered 35% of normal BCKDH activity. As PP2Cm has been described essential for cell survival, apoptosis and metabolism, the impact of its deficiency on specific metabolic stress variables was evaluated in PP2Cm-deficient fibroblasts. Increases were seen in ROS levels along with the activation of specific stress-signaling MAP kinases. Similar to that described for the pyruvate dehydrogenase complex, a defect in the regulation of BCKDH caused the aberrant metabolism of its substrate, contributing to the patient's MSUD phenotype--and perhaps others. © 2012 WILEY PERIODICALS, INC.

Doxycycline alters collagen composition following ventral hernia repair.

PubMed

Tharappel, Job C; Harris, Jennifer W; Totten, Crystal; Zwischenberger, Brittany A; Roth, John S

2017-04-01

Doxycycline, a nonspecific metalloproteinase (MMP) inhibitor, has been demonstrated to impact the strength of the polypropylene (PP) mesh-repaired hernia with an increase in the deposition of collagen type 1. The impact of doxycycline with porcine acellular dermal matrices (PADM) is unknown; therefore, we evaluated the impact of doxycycline administration upon hernia repair with PP and PADM mesh. Sprague-Dawley rats weighing ~400 g underwent laparotomy with creation of a midline ventral hernia. After a 27-day recovery, animals were randomly assigned to four groups of eight and underwent intraperitoneal underlay hernia repair with either PP or PADM. Groups were assigned to daily normal saline (S) or daily doxycycline in normal saline 10 mg/kg (D) via oral gavage for 8 weeks beginning 24 h preoperatively. Animals were euthanized at 8 weeks and underwent tensiometric testing of the abdominal wall and western blot analyses for collagen subtypes and MMPs. Thirty-two animals underwent successful hernia creation and repair with either PADM or PP. At 8 weeks, 15 of 16 PP-implanted animals survived with only 12 of 16 PADM-implanted animals surviving. There were no differences in the mesh to fascial interface tensiometric strength between groups. Densitometric counts in the PADM-D group demonstrated increased collagen type 1 compared to PP-S (PADM-D [1286.5], PADM-S [906.9], PP-S [700.4], p = 0.037) and decreased collagen type 3 compared to PP-S (PADM-D [7446.9], PADM-S [8507.6], PP-S [11,297.1], p = 0.01). MMP-9 levels were increased in PADM-D (PP-S vs. PADM-D, p = 0.04), while MMP-2 levels were similar between PADM-D and PADM-S, respectively. Collagen type 1 deposition at the mesh to fascial interface is enhanced following administration of doxycycline in ventral hernia repairs with porcine acellular dermal matrices. Doxycycline administration may have implications for enhancing hernia repair outcomes using biologic mesh.

PP2A regulates autophagy in two alternative ways in Drosophila.

PubMed

Bánréti, Ágnes; Lukácsovich, Tamás; Csikós, György; Erdélyi, Miklós; Sass, Miklós

2012-04-01

Protein phosphatase 2A (PP2A) holoenzyme is a heterotrimeric complex, consisting of A, B and C subunits. The catalytic subunit PP2A-C (microtubule star/mts) binds to the C-terminal part of the scaffold protein PP2A-A (PP2A-29B). In Drosophila, there are three different forms of B subunits (widerborst/wdb, twins/tws and PP2A-B'), which determine the subcellular localization and substrate specificity of the holoenzyme. Previous studies demonstrated that PP2A is involved in the control of TOR-dependent autophagy both in yeast and mammals. Furthermore, in Drosophila, wdb genetically interacts with the PtdIns3K/PTEN/Akt signaling cascade, which is a main upstream regulatory system of dTOR. Here we demonstrate that in Drosophila, two different PP2A complexes (containing B' or wdb subunit) play essential roles in the regulation of starvation-induced autophagy. The PP2A-A/wdb/C complex acts upstream of dTOR, whereas the PP2A-A/B'/C complex functions as a target of dTOR and may regulate the elongation of autophagosomes and their subsequent fusion with lysosomes. We also identified three Drosophila Atg orthologs (Atg14, Atg17 and Atg101), which represent potential targets of the PP2A-A/B'/C complex during autophagy.

Effect of total solids content on biohydrogen production and lactic acid accumulation during dark fermentation of organic waste biomass.

PubMed

Ghimire, Anish; Trably, Eric; Frunzo, Luigi; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni; Cazier, Elisabeth A; Escudié, Renaud

2018-01-01

Production of biohydrogen and related metabolic by-products was investigated in Solid State Dark Fermentation (SSDF) of food waste (FW) and wheat straw (WS). The effect of the total solids (TS) content and H 2 partial pressure (pp H2 ), two of the main operating factors of SSDF, were investigated. Batch tests with FW at 10, 15, 20, 25 and 30% TS showed considerable effects of the TS on metabolites distribution. H 2 production was strongly inhibited for TS contents higher than 15% with a concomitant accumulation of lactic acid and a decrease in substrate conversion. Varying the pp H2 had no significant effect on the conversion products and overall degradation of FW and WS, suggesting that pp H2 was not the main limiting factor in SSDF. This study showed that the conversion of complex substrates by SSDF depends on the substrate type and is limited by the TS content. Copyright © 2017 Elsevier Ltd. All rights reserved.

Statin-activated nuclear receptor PXR promotes SGK2 dephosphorylation by scaffolding PP2C to induce hepatic gluconeogenesis.

PubMed

Gotoh, Saki; Negishi, Masahiko

2015-09-22

Statin therapy is known to increase blood glucose levels in humans. Statins utilize pregnane X receptor (PXR) and serum/glucocorticoid regulated kinase 2 (SGK2) to activate phosphoenolpyruvate carboxykinase 1 (PEPCK1) and glucose-6-phosphatase (G6Pase) genes, thereby increasing glucose production in human liver cells. Here, the novel statin/PXR/SGK2-mediated signaling pathway has now been characterized for hepatic gluconeogenesis. Statin-activated PXR scaffolds the protein phosphatase 2C (PP2C) and SGK2 to stimulate PP2C to dephosphorylate SGK2 at threonine 193. Non-phosphorylated SGK2 co-activates PXR-mediated trans-activation of promoters of gluconeogenic genes in human liver cells, thereby enhancing gluconeogenesis. This gluconeogenic statin-PXR-SGK2 signal is not present in mice, in which statin treatment suppresses hepatic gluconeogenesis. These findings provide the basis for statin-associated side effects such as an increased risk for Type 2 diabetes.

A wheat (Triticum aestivum) protein phosphatase 2A catalytic subunit gene provides enhanced drought tolerance in tobacco.

PubMed

Xu, Chongyi; Jing, Ruilian; Mao, Xinguo; Jia, Xiaoyun; Chang, Xiaoping

2007-03-01

Multiple copies of genes encoding the catalytic subunit (c) of protein phosphatase 2A (PP2A) are commonly found in plants. For some of these genes, expression is up-regulated under water stress. The aim of this study was to investigate expression and characterization of TaPP2Ac-1 from Triticum aestivum, and to evaluate the effects of TaPP2Ac-1 on Nicotiana benthamiana in response to water stress. TaPP2Ac-1 cDNA was isolated from wheat by in silico identification and RT-PCR amplification. Transcript levels of TaPP2Ac-1 were examined in wheat responding to water deficit. Copy numbers of TaPP2Ac-1 in wheat genomes and subcellular localization in onion epidermal cells were studied. Enzyme properties of the recombinant TaPP2Ac-1 protein were determined. In addition, studies were carried out in tobacco plants with pCAPE2-TaPP2Ac-1 under water-deficit conditions. TaPP2Ac-1 cDNA was cloned from wheat. Transcript levels of TaPP2Ac-1 in wheat seedlings were up-regulated under drought condition. One copy for this TaPP2Ac-1 was present in each of the three wheat genomes. TaPP2Ac-1 fused with GFP was located in the nucleus and cytoplasm of onion epidermis cells. The recombinant TaPP2Ac-1 gene was over-expressed in Escherichia coli and encoded a functional serine/threonine phosphatase. Transgenic tobacco plants over-expressing TaPP2Ac-1 exhibited stronger drought tolerance than non-transgenic tobacco plants. Tobacco plants with pCAPE2-TaPP2Ac-1 appeared to be resistant to water deficit, as shown by their higher capacity to maintain leaf relative water content, leaf cell-membrane stability index, water-retention ability and water use efficiency under water stress. The results suggest that the physiological role of TaPP2Ac-1 is related to drought stress response, possibly through its involvement in drought-responding signal transduction pathways.

SILAC-based phosphoproteomics reveals new PP2A-Cdc55-regulated processes in budding yeast.

PubMed

Baro, Barbara; Játiva, Soraya; Calabria, Inés; Vinaixa, Judith; Bech-Serra, Joan-Josep; de LaTorre, Carolina; Rodrigues, João; Hernáez, María Luisa; Gil, Concha; Barceló-Batllori, Silvia; Larsen, Martin R; Queralt, Ethel

2018-05-01

Protein phosphatase 2A (PP2A) is a family of conserved serine/threonine phosphatases involved in several essential aspects of cell growth and proliferation. PP2ACdc55 phosphatase has been extensively related to cell cycle events in budding yeast; however, few PP2ACdc55 substrates have been identified. Here, we performed a quantitative mass spectrometry approach to reveal new substrates of PP2ACdc55 phosphatase and new PP2A-related processes in mitotic arrested cells. We identified 62 statistically significant PP2ACdc55 substrates involved mainly in actin-cytoskeleton organization. In addition, we validated new PP2ACdc55 substrates such as Slk19 and Lte1, involved in early and late anaphase pathways, and Zeo1, a component of the cell wall integrity pathway. Finally, we constructed docking models of Cdc55 and its substrate Mob1. We found that the predominant interface on Cdc55 is mediated by a protruding loop consisting of residues 84-90, thus highlighting the relevance of these aminoacids for substrate interaction. We used phosphoproteomics of Cdc55-deficient cells to uncover new PP2ACdc55 substrates and functions in mitosis. As expected, several hyperphosphorylated proteins corresponded to Cdk1-dependent substrates, although other kinases' consensus motifs were also enriched in our dataset, suggesting that PP2ACdc55 counteracts and regulates other kinases distinct from Cdk1. Indeed, Pkc1 emerged as a novel node of PP2ACdc55 regulation, highlighting a major role of PP2ACdc55 in actin cytoskeleton and cytokinesis, gene ontology terms significantly enriched in the PP2ACdc55-dependent phosphoproteome.

Brachypodium distachyon BdPP2CA6 Interacts with BdPYLs and BdSnRK2 and Positively Regulates Salt Tolerance in Transgenic Arabidopsis

PubMed Central

Zhang, Fan; Wei, Qiuhui; Shi, Jiaochun; Jin, Xia; He, Yuan; Zhang, Yang; Luo, Qingchen; Wang, Yuesheng; Chang, Junli; Yang, Guangxiao; He, Guangyuan

2017-01-01

The phytohormone abscisic acid (ABA) is essential in plant responding to biotic and abiotic stresses. Although ABA signaling model is well established in Arabidopsis, ABA receptor PYL family and clade A PP2C subfamily are not yet characterized in monocot model plant Brachypodium distachyon. In this study, we identified 12 PYLs and 8 clade A PP2Cs from B. distachyon genome and successfully cloned 12 PYLs and 7 clade A PP2Cs. Bioinformatic and expression analyses showed that most of the identified genes respond to several signal molecules and abiotic stresses. Protein–protein interaction analysis revealed that many BdPYLs and BdPP2CAs participate in the classic ABA-PYL-PP2C-SnRK2 signaling pathway. A clade A PP2C, designated BdPP2CA6, interacted with BdPYL11 in the absence of ABA and localized in nucleus. Most clade A PP2C members from Arabidopsis showed negatively regulation in ABA signaling pathway, whereas BdPP2CA6-overexpression transgenic Arabidopsis showed ABA hypersensitive phenotype, resulting in enhanced stomatal closure and salinity tolerance. Our results indicate that BdPP2CA6 positively regulates ABA and stress signal pathway in transgenic Arabidopsis plant seedlings. PMID:28293246

PpCBF3 from Cold-Tolerant Kentucky Bluegrass Involved in Freezing Tolerance Associated with Up-Regulation of Cold-Related Genes in Transgenic Arabidopsis thaliana

PubMed Central

Chen, Yu; Xu, Bin; Yang, Zhimin; Huang, Bingru

2015-01-01

Dehydration-Responsive Element Binding proteins (DREB)/C-repeat (CRT) Binding Factors (CBF) have been identified as transcriptional activators during plant responses to cold stress. The objective of this study was to determine the physiological roles of a CBF gene isolated from a cold-tolerant perennial grass species, Kentucky bluegrass (Poa pratensis L.), which designated as PpCBF3, in regulating plant tolerance to freezing stress. Transient transformation of Arabidopsis thaliana mesophyll protoplast with PpCBF3-eGFP fused protein showed that PpCBF3 was localized to the nucleus. RT-PCR analysis showed that PpCBF3 was specifically induced by cold stress (4°C) but not by drought stress [induced by 20% polyethylene glycol 6000 solution (PEG-6000)] or salt stress (150 mM NaCl). Transgenic Arabidopsis overexpressing PpCBF3 showed significant improvement in freezing (-20°C) tolerance demonstrated by a lower percentage of chlorotic leaves, lower cellular electrolyte leakage (EL) and H2O2 and O2 .- content, and higher chlorophyll content and photochemical efficiency compared to the wild type. Relative mRNA expression level analysis by qRT-PCR indicated that the improved freezing tolerance of transgenic Arabidopsis plants overexpressing PpCBF3 was conferred by sustained activation of downstream cold responsive (COR) genes. Other interesting phenotypic changes in the PpCBF3-transgenic Arabidopsis plants included late flowering and slow growth or ‘dwarfism’, both of which are desirable phenotypic traits for perennial turfgrasses. Therefore, PpCBF3 has potential to be used in genetic engineering for improvement of turfgrass freezing tolerance and other desirable traits. PMID:26177510

Transcriptional control of stem cell fate by E2Fs and pocket proteins

PubMed Central

Julian, Lisa M.; Blais, Alexandre

2015-01-01

E2F transcription factors and their regulatory partners, the pocket proteins (PPs), have emerged as essential regulators of stem cell fate control in a number of lineages. In mammals, this role extends from both pluripotent stem cells to those encompassing all embryonic germ layers, as well as extra-embryonic lineages. E2F/PP-mediated regulation of stem cell decisions is highly evolutionarily conserved, and is likely a pivotal biological mechanism underlying stem cell homeostasis. This has immense implications for organismal development, tissue maintenance, and regeneration. In this article, we discuss the roles of E2F factors and PPs in stem cell populations, focusing on mammalian systems. We discuss emerging findings that position the E2F and PP families as widespread and dynamic epigenetic regulators of cell fate decisions. Additionally, we focus on the ever expanding landscape of E2F/PP target genes, and explore the possibility that E2Fs are not simply regulators of general ‘multi-purpose’ cell fate genes but can execute tissue- and cell type-specific gene regulatory programs. PMID:25972892

Two-photon polymerization for fabrication of biomedical devices

NASA Astrophysics Data System (ADS)

Ovsianikov, Aleksandr; Doraiswamy, Anand; Narayan, R.; Chichkov, B. N.

2007-01-01

Two-photon polymerization (2PP) is a novel technology which allows the fabrication of complex three-dimensional (3D) microstructures and nanostructures. The number of applications of this technology is rapidly increasing; it includes the fabrication of 3D photonic crystals [1-4], medical devices, and tissue scaffolds [5-6]. In this contribution, we discuss current applications of 2PP for microstructuring of biomedical devices used in drug delivery. While in general this sector is still dominated by oral administration of drugs, precise dosing, safety, and convenience are being addressed by transdermal drug delivery systems. Currently, main limitations arise from low permeability of the skin. As a result, only few types of pharmacological substances can be delivered in this manner [7]. Application of microneedle arrays, whose function is to help overcome the barrier presented by the epidermis layer of the skin, provides a very promising solution. Using 2PP we have fabricated arrays of hollow microneedles with different geometries. The effect of microneedle geometry on skin penetration is examined. Our results indicate that microneedles created using 2PP technique are suitable for in vivo use, and for integration with the next generation of MEMS- and NEMS-based drug delivery devices.

Foot deformities, function in the lower extremities, and plantar pressure in patients with diabetes at high risk to develop foot ulcers.

PubMed

Tang, Ulla Hellstrand; Zügner, Roland; Lisovskaja, Vera; Karlsson, Jon; Hagberg, Kerstin; Tranberg, Roy

2015-01-01

Foot deformities, neuropathy, and dysfunction in the lower extremities are known risk factors that increase plantar peak pressure (PP) and, as a result, the risk of developing foot ulcers in patients with diabetes. However, knowledge about the prevalence of these factors is still limited. The aim of the present study was to describe the prevalence of risk factors observed in patients with diabetes without foot ulcers and to explore possible connections between the risk factors and high plantar pressure. Patients diagnosed with type 1 (n=27) or type 2 (n=47) diabetes (mean age 60.0±15.0 years) were included in this cross-sectional study. Assessments included the registration of foot deformities; test of gross function at the hip, knee, and ankle joints; a stratification of the risk of developing foot ulcers according to the Swedish National Diabetes Register; a walking test; and self-reported questionnaires including the SF-36 health survey. In-shoe PP was measured in seven regions of interests on the sole of the foot using F-Scan(®). An exploratory analysis of the association of risk factors with PP was performed. Neuropathy was present in 28 (38%), and 39 (53%) had callosities in the heel region. Low forefoot arch was present in 57 (77%). Gait-related parameters, such as the ability to walk on the forefoot or heel, were normal in all patients. Eighty percent had normal function at the hip and ankle joints. Gait velocity was 1.2±0.2 m/s. All patients were stratified to risk group 3. Hallux valgus and hallux rigidus were associated with an increase in the PP in the medial forefoot. A higher body mass index (BMI) was found to increase the PP at metatarsal heads 4 and 5. Pes planus was associated with a decrease in PP at metatarsal head 1. Neuropathy did not have a high association with PP. This study identified several potential risk factors for the onset of diabetic foot ulcers (DFU). Hallux valgus and hallux rigidus appeared to increase the PP under the medial forefoot and a high BMI appeared to increase the PP under the lateral forefoot. There is a need to construct a simple, valid, and reliable assessment routine to detect potential risk factors for the onset of DFU.

Human cytomegalovirus tegument protein pp150 acts as a cyclin A2-CDK-dependent sensor of the host cell cycle and differentiation state.

PubMed

Bogdanow, Boris; Weisbach, Henry; von Einem, Jens; Straschewski, Sarah; Voigt, Sebastian; Winkler, Michael; Hagemeier, Christian; Wiebusch, Lüder

2013-10-22

Upon cell entry, herpesviruses deliver a multitude of premade virion proteins to their hosts. The interplay between these incoming proteins and cell-specific regulatory factors dictates the outcome of infections at the cellular level. Here, we report a unique type of virion-host cell interaction that is essential for the cell cycle and differentiation state-dependent onset of human cytomegalovirus (HCMV) lytic gene expression. The major tegument 150-kDa phosphoprotein (pp150) of HCMV binds to cyclin A2 via a functional RXL/Cy motif resulting in its cyclin A2-dependent phosphorylation. Alanine substitution of the RXL/Cy motif prevents this interaction and allows the virus to fully escape the cyclin-dependent kinase (CDK)-mediated block of immediate early (IE) gene expression in S/G2 phase that normally restricts the onset of the HCMV replication cycle to G0/G1. Furthermore, the cyclin A2-CDK-pp150 axis is also involved in the establishment of HCMV quiescence in NTera2 cells, showing the importance of this molecular switch for differentiation state-dependent regulation of IE gene expression. Consistent with the known nucleocapsid-binding function of pp150, its RXL/Cy-dependent phosphorylation affects gene expression of the parental virion only, suggesting a cis-acting, virus particle-associated mechanism of control. The pp150 homologs of other primate and mammalian CMVs lack an RXL/Cy motif and accordingly even the nearest relative of HCMV, chimpanzee CMV, starts its lytic cycle in a cell cycle-independent manner. Thus, HCMV has evolved a molecular sensor for cyclin A2-CDK activity to restrict its IE gene expression program as a unique level of self-limitation and adaptation to its human host.

Protein phosphatase 2A regulates deoxycytidine kinase activity via Ser-74 dephosphorylation.

PubMed

Amsailale, Rachid; Beyaert, Maxime; Smal, Caroline; Janssens, Veerle; Van Den Neste, Eric; Bontemps, Françoise

2014-03-03

Deoxycytidine kinase (dCK) is a critical enzyme for activation of anticancer nucleoside analogs. Its activity is controlled via Ser-74 phosphorylation. Here, we investigated which Ser/Thr phosphatase dephosphorylates Ser-74. In cells, the PP1/PP2A inhibitor okadaic acid increased both dCK activity and Ser-74 phosphorylation at concentrations reported to specifically target PP2A. In line with this, purified PP2A, but not PP1, dephosphorylated recombinant pSer-74-dCK. In cell lysates, the Ser-74-dCK phosphatase activity was found to be latent, Mn(2+)-activated, responsive to PP2A inhibitors, and diminished after PP2A-immunodepletion. Use of siRNAs allowed concluding definitively that PP2A constitutively dephosphorylates dCK in cells and negatively regulates its activity. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Protein Phosphatase 2A Regulates Innate Immune and Proteolytic Responses to Cigarette Smoke Exposure in the Lung

PubMed Central

Wallace, Alison M.; Hardigan, Andrew; Geraghty, Patrick; Salim, Shaneeza; Gaffney, Adam; Thankachen, Jincy; Arellanos, Leo; D'Armiento, Jeanine M.; Foronjy, Robert F.

2012-01-01

Protein phosphatase 2A (PP2A) is the primary serine-threonine phosphatase of eukaryotic cells, and changes in its activity have been linked to neoplastic and neurodegenerative diseases. However, the role of PP2A in noncancerous lung diseases such as chronic obstructive pulmonary disease (COPD) has not been previously examined. This study determined that PP2A activity was significantly increased in the lungs of advanced emphysema subjects compared with age-matched controls. Furthermore, we found that cigarette smoke exposure increases PP2A activity in mouse lung in vivo and in primary human small airway epithelial (SAE) cells in vitro. In mice, intratracheal transfection of PP2A protein prior to cigarette smoke exposure prevented acute smoke–induced lung inflammation. Conversely, inhibiting PP2A activity during smoke exposure exacerbated inflammatory responses in the lung. To further determine how PP2A modulates the responses to cigarette smoke in the lung, enzyme levels were manipulated in SAE cells using protein transfection and short hairpin RNA (shRNA) techniques. Increasing PP2A activity in SAE cells via PP2A protein transfection downregulated cytokine expression and prevented the induction of proteases following cigarette smoke extract (CSE) treatment. Conversely, decreasing enzymatic activity by stably transfecting SAE cells with shRNA for the A subunit of PP2A exacerbated these smoke-mediated responses. This study establishes that PP2A induction by cigarette smoke modulates immune and proteolytic responses to cigarette smoke exposure. Together, these findings suggest that manipulation of PP2A activity may be a plausible means to treat COPD and other inflammatory diseases. PMID:22223484

Preparation and characterization of thick-film Ni/MH battery.

PubMed

Do, Jing-Shan; Yu, Sen-Hao; Cheng, Suh-Fen

2004-07-30

Using the porous polypropylene (PP) films sputtered with gold and the Ni as current collectors, the electroactive materials (Ni(OH)2 and metal hydride (MH)) of positive and negative electrodes were prepared on the current collector using thick-film technology. Two types of cell configurations were prepared and the characteristics of these batteries were compared. The cycle number for the formation of batteries based on the porous PP film was found to be 2, which was significantly less than that of batteries based on the ceramic substrates. Using the porous PP film as substrate, the number of cycles for the formation of battery increased from 2 to 5 with the increase of the charge/discharge rate from 0.1C/0.025C to 2.0C/0.5C. The silver oxides dendrites formed by the oxidation of silver paste used to adhere the current collectors and the conducting wires in the charge/discharge process caused a short contact between the positive and negative electrodes, which then caused the battery failure. The cycle life of the battery based on the porous PP film was found to be greater than 400 when the charge/discharge rate was 2.0C/0.5C.

Characterization of ppGalNAc-T18, a member of the vertebrate-specific Y subfamily of UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferases.

PubMed

Li, Xing; Wang, Jing; Li, Wei; Xu, Yingjiao; Shao, Dong; Xie, Yinyin; Xie, Wenxian; Kubota, Tomomi; Narimatsu, Hisashi; Zhang, Yan

2012-05-01

The first step of mucin-type O-glycosylation is catalyzed by members of the UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase (ppGalNAc-T; EC 2.4.1.41) family. Each member of this family has unique substrate specificity and expression profiles. In this report, we describe a new subfamily of ppGalNAc-Ts, designated the Y subfamily. The Y subfamily consists of four members, ppGalNAc-T8, -T9, -T17 and -T18, in which the conserved YDX(5)WGGENXE sequence in the Gal/GalNAc-T motif of ppGalNAc-Ts is mutated to LDX(5)YGGENXE. Phylogenetic analysis revealed that the Y subfamily members only exist in vertebrates. All four Y subfamily members lack in vitro GalNAc-transferase activity toward classical substrates possibly because of the UDP-GalNAc-binding pocket mutants. However, ppGalNAc-T18, the newly identified defining member, was localized in the endoplasmic reticulum rather than the Golgi apparatus in lung carcinoma cells. The knockdown of ppGalNAc-T18 altered cell morphology, proliferation potential and changed cell O-glycosylation. ppGalNAc-T18 can also modulate the in vitro GalNAc-transferase activity of ppGalNAc-T2 and -T10, suggesting that it may be a chaperone-like protein. These findings suggest that the new Y subfamily of ppGalNAc-Ts plays an important role in protein glycosylation; characterizing their functions will provide new insight into the role of ppGalNAc-Ts.

Microcystin-LR Induced Reactive Oxygen Species Mediate Cytoskeletal Disruption and Apoptosis of Hepatocytes in Cyprinus carpio L.

PubMed Central

Jiang, Jinlin; Shan, Zhengjun; Xu, Weili; Wang, Xiaorong; Zhou, Junying; Kong, Deyang; Xu, Jing

2013-01-01

Microcystins (MCs) are a group of cyclic hepatotoxic peptides produced by cyanobacteria. Microcystin-LR (MC-LR) contains Leucine (L) and Arginine (R) in the variable positions, and is one of the most common and potently toxic peptides. MC-LR can inhibit protein phosphatase type 1 and type 2A (PP1 and PP2A) activities and induce excessive production of reactive oxygen species (ROS). The underlying mechanism of the inhibition of PP1 and PP2A has been extensively studied. The over-production of ROS is considered to be another main mechanism behind MC-LR toxicity; however, the detailed toxicological mechanism involved in over-production of ROS in carp (Cyprinus carpio L.) remains largely unclear. In our present study, the hydroxyl radical (•OH) was significantly induced in the liver of carp after a relatively short-term exposure to MC-LR. The elevated reactive oxygen species (ROS) production may play an important role in the disruption of microtubule structure. Pre-injection of the antioxidant N-acetyl-cysteine (NAC) provided significant protection to the cytoskeleton, however buthionine sulfoximine (BSO) exacerbated cytoskeletal destruction. In addition, the elevated ROS formation induced the expression of apoptosis-related genes, including p38, JNKa, and bcl-2. A significant increase in apoptotic cells was observed at 12 - 48 hours. Our study further supports evidence that ROS are involved in MC-LR induced damage to liver cells in carp, and indicates the need for further study of the molecular mechanisms behind MC-LR toxicity. PMID:24376844

Avirulence gene mapping in the Hessian fly (Mayetiola destructor) reveals a protein phosphatase 2C effector gene family.

PubMed

Zhao, Chaoyang; Shukle, Richard; Navarro-Escalante, Lucio; Chen, Mingshun; Richards, Stephen; Stuart, Jeffrey J

2016-01-01

The genetic tractability of the Hessian fly (HF, Mayetiola destructor) provides an opportunity to investigate the mechanisms insects use to induce plant gall formation. Here we demonstrate that capacity using the newly sequenced HF genome by identifying the gene (vH24) that elicits effector-triggered immunity in wheat (Triticum spp.) seedlings carrying HF resistance gene H24. vH24 was mapped within a 230-kb genomic fragment near the telomere of HF chromosome X1. That fragment contains only 21 putative genes. The best candidate vH24 gene in this region encodes a protein containing a secretion signal and a type-2 serine/threonine protein phosphatase (PP2C) domain. This gene has an H24-virulence associated insertion in its promoter that appears to silence transcription of the gene in H24-virulent larvae. Candidate vH24 is a member of a small family of genes that encode secretion signals and PP2C domains. It belongs to the fraction of genes in the HF genome previously predicted to encode effector proteins. Because PP2C proteins are not normally secreted, our results suggest that these are PP2C effectors that HF larvae inject into wheat cells to redirect, or interfere, with wheat signal transduction pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

Retinoic Acid Modulates Interferon-γ Production by Hepatic Natural Killer T Cells via Phosphatase 2A and the Extracellular Signal-Regulated Kinase Pathway

PubMed Central

Chang, Heng-Kwei

2015-01-01

Retinoic acid (RA), an active metabolite converted from vitamin A, plays an active role in immune function, such as defending against infections and immune regulation. Although RA affects various types of immune cells, including antigen-presenting cells, B lymphocytes, and T lymphocytes, whether it affects natural killer T (NKT) cells remain unknown. In this study, we found that RA decreased interferon (IFN)-γ production by activated NKT cells through T-cell receptor (TCR) and CD28. We also found that RA reduced extracellular signal-regulated kinase (ERK) phosphorylation, but increased phosphatase 2A (PP2A) activity in TCR/CD28-stimulated NKT cells. The increased PP2A activity, at least partly, contributed to the reduction of ERK phosphorylation. Since inhibition of ERK activation decreases IFN-γ production by TCR/CD28-stimulated NKT cells, RA may downregulate IFN-γ production by TCR/CD28-stimulated NKT cells through the PP2A-ERK pathway. Our results demonstrated a novel function of RA in modulating the IFN-γ expression by activated NKT cells. PMID:25343668

Hypothermia mediates age-dependent increase of tau phosphorylation in db/db mice.

PubMed

El Khoury, Noura B; Gratuze, Maud; Petry, Franck; Papon, Marie-Amélie; Julien, Carl; Marcouiller, François; Morin, Françoise; Nicholls, Samantha B; Calon, Frédéric; Hébert, Sébastien S; Marette, André; Planel, Emmanuel

2016-04-01

Accumulating evidence from epidemiological studies suggest that type 2 diabetes is linked to an increased risk of Alzheimer's disease (AD). However, the consequences of type 2 diabetes on AD pathologies, such as tau hyperphosphorylation, are not well understood. Here, we evaluated the impact of type 2 diabetes on tau phosphorylation in db/db diabetic mice aged 4 and 26weeks. We found increased tau phosphorylation at the CP13 epitope correlating with a deregulation of c-Jun. N-terminal kinase (JNK) and Protein Phosphatase 2A (PP2A) in 4-week-old db/db mice. 26-week-old db/db mice displayed tau hyperphosphorylation at multiple epitopes (CP13, AT8, PHF-1), but no obvious change in kinases or phosphatases, no cleavage of tau, and no deregulation of central insulin signaling pathways. In contrast to younger animals, 26-week-old db/db mice were hypothermic and restoration of normothermia rescued phosphorylation at most epitopes. Our results suggest that, at early stages of type 2 diabetes, changes in tau phosphorylation may be due to deregulation of JNK and PP2A, while at later stages hyperphosphorylation is mostly a consequence of hypothermia. These results provide a novel link between diabetes and tau pathology, and underlie the importance of recording body temperature to better understand the relationship between diabetes and AD. Copyright © 2016 Elsevier Inc. All rights reserved.

A novel protein phosphatase 2A (PP2A) is involved in the transformation of human protozoan parasite Trypanosoma cruzi.

PubMed Central

González, Jorge; Cornejo, Alberto; Santos, Marcia R M; Cordero, Esteban M; Gutiérrez, Bessy; Porcile, Patricio; Mortara, Renato A; Sagua, Hernán; Da Silveira, José Franco; Araya, Jorge E

2003-01-01

Here we provide evidence for a critical role of PP2As (protein phosphatase 2As) in the transformation of Trypanosoma cruzi. In axenic medium at pH 5.0, trypomastigotes rapidly transform into amastigotes, a process blocked by okadaic acid, a potent PP2A inhibitor, at concentrations as low as 0.1 microM. 1-Norokadaone, an inactive okadaic acid analogue, did not affect the transformation. Electron microscopy studies indicated that okadaic acid-treated trypomastigotes had not undergone ultrastructural modifications, reinforcing the idea that PP2A inhibits transformation. Using a microcystin-Sepharose affinity column we purified the native T. cruzi PP2A. The enzyme displayed activity against 32P-labelled phosphorylase a that was inhibited in a dose-dependent manner by okadaic acid. The protein was also submitted to MS and, from the peptides obtained, degenerate primers were used to clone a novel T. cruzi PP2A enzyme by PCR. The isolated gene encodes a protein of 303 amino acids, termed TcPP2A, which displayed a high degree of homology (86%) with the catalytic subunit of Trypanosoma brucei PP2A. Northern-blot analysis revealed the presence of a major 2.1-kb mRNA hybridizing in all T. cruzi developmental stages. Southern-blot analysis suggested that the TcPP2A gene is present in low copy number in the T. cruzi genome. These results are consistent with the mapping of PP2A genes in two chromosomal bands by pulsed-field gel electrophoresis and chromoblot hybridization. Our studies suggest that in T. cruzi PP2A is important for the complete transformation of trypomastigotes into amastigotes during the life cycle of this protozoan parasite. PMID:12737627

Protein Phosphatase 1-α Regulates AS160 Ser588 and Thr642 Dephosphorylation in Skeletal Muscle.

PubMed

Sharma, Pragya; Arias, Edward B; Cartee, Gregory D

2016-09-01

Akt substrate of 160 kDa (AS160) phosphorylation on Thr(642) and Ser(588) by Akt is essential for insulin's full effect on glucose transport. However, protein phosphorylation is determined by the balance of actions by kinases and phosphatases, and the specific phosphatase(s) controlling AS160 dephosphorylation is (are) unknown. Accordingly, we assessed roles of highly expressed skeletal muscle serine/threonine phosphatases (PP1, PP2A, PP2B, and PP2C) on AS160 dephosphorylation. Preliminary screening of candidate phosphatases used an AS160 dephosphorylation assay. Lysates from insulin-stimulated skeletal muscle were treated with pharmacological phosphatase inhibitors and assessed for AS160 Ser(588) and Thr(642) dephosphorylation. AS160 dephosphorylation on both phosphorylation sites was unaltered by PP2B or PP2C inhibitors. Okadaic acid (low dose inhibits PP2A; high dose inhibits PP1) delayed AS160 Ser(588) (both doses) and Thr(642) (high dose only) dephosphorylation concomitant with greater Akt phosphorylation (both doses). AS160 was coimmunoprecipitated with PP1-α but not with PP1-β, PP1-γ1, or PP2A. Recombinant inhibitor-2 protein (a selective PP1 inhibitor) delayed AS160 dephosphorylation on both phosphorylation sites without altering Akt phosphorylation. Furthermore, knockdown of PP1-α but not PP1-β or PP1-γ1 by small interfering RNA caused greater AS160 Ser(588) and Thr(642) phosphorylation concomitant with unaltered Akt phosphorylation. Together, these results identified PP1-α as a regulator of AS160 Thr(642) and Ser(588) dephosphorylation in skeletal muscle. © 2016 by the American Diabetes Association.

The relative hydrolytic reactivities of pyrophosphites and pyrophosphates.

PubMed

Mistry, Dharmit; Powles, Nicholas

2013-09-14

The pH-rate profiles for the hydrolysis of pyrophosphate (PP(V)) and pyrophosphite (PP(III), pyro-di-H-phosphonate) are a complex function of pH, reflecting the different ionic species and their relative reactivities. PP(III) is more reactive than PP(V) at all pHs and only PP(III) shows a hydroxide-ion reaction at high pH, so it is 10(10)-fold more reactive than PP(V) in 0.1 M NaOH. The pK(a2) of PP(III) ~0.44, so the dominant species at pH's > 1 is the di-anion PP(III)(2-). Although there is no observable (NMR or ITC) binding of Mg(2+) to the PP(III) di-anion there is a modest increase in the rate of hydrolysis of PP(III) by Mg(2+). PP(III) is neither a substrate nor an inhibitor of pyrophosphatase, the enzyme that efficiently catalyses the hydrolysis of PP(V).

Dormancy-Associated MADS-Box (DAM) and the Abscisic Acid Pathway Regulate Pear Endodormancy Through a Feedback Mechanism.

PubMed

Tuan, Pham Anh; Bai, Songling; Saito, Takanori; Ito, Akiko; Moriguchi, Takaya

2017-08-01

In the pear 'Kosui' (Pyrus pyrifolia Nakai), the dormancy-associated MADS-box (PpDAM1 = PpMADS13-1) gene has been reported to play an essential role in bud endodormancy. Here, we found that PpDAM1 up-regulated expression of 9-cis-epoxycarotenoid dioxygenase (PpNCED3), which is a rate-limiting gene for ABA biosynthesis. Transient assays with a dual luciferase reporter system (LUC assay) and electrophoretic mobility shift assay (EMSA) showed that PpDAM1 activated PpNCED3 expression by binding to the CArG motif in the PpNCED3 promoter. PpNCED3 expression was increased toward endodormancy release in lateral flower buds of 'Kosui', which is consistent with the induced levels of ABA, its catabolism (ABA 8'-hydroxylase) and signaling genes (type 2C protein phosphatase genes and SNF1-related protein kinase 2 genes). In addition, we found that an ABA response element (ABRE)-binding transcription factor, PpAREB1, exhibiting high expression concomitant with endodormancy release, bound to three ABRE motifs in the promoter region of PpDAM1 and negatively regulated its activity. Taken together, our results suggested a feedback regulation between PpDAM1 and the ABA metabolism and signaling pathway during endodormancy of pear. This first evidence of an interaction between a DAM and ABA biosynthesis in vitro will provide further insights into bud endodormancy regulatory mechanisms of deciduous trees including pear. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

I(2)(PP2A) regulates p53 and Akt correlatively and leads the neurons to abort apoptosis.

PubMed

Liu, Gong-Ping; Wei, Wei; Zhou, Xin; Zhang, Yao; Shi, Hai-Hong; Yin, Jun; Yao, Xiu-Qing; Peng, Cai-Xia; Hu, Juan; Wang, Qun; Li, Hong-Lian; Wang, Jian-Zhi

2012-02-01

A chronic neuron loss is the cardinal pathology in Alzheimer disease (AD), but it is still not understood why most neurons in AD brain do not accomplish apoptosis even though they are actually exposed to an environment with enriched proapoptotic factors. Protein phosphatase-2A inhibitor-2 (I(2)(PP2A)), an endogenous PP2A inhibitor, is significantly increased in AD brain, but the role of I(2)(PP2A) in AD-like neuron loss is elusive. Here, we show that I(2)(PP2A) regulates p53 and Akt correlatively. The mechanisms involve activated transcription and p38 MAPK activities. More importantly, we demonstrate that the simultaneous activation of Akt induced by I(2)(PP2A) counteracts the hyperactivated p53-induced cell apoptosis. Furthermore, I(2)(PP2A), p53 and Akt are all elevated in the brain of mouse model and AD patients. Our results suggest that the increased I(2)(PP2A) may trigger apoptosis by p53 upregulation, but due to simultaneous activation of Akt, the neurons are aborted from the apoptotic pathway. This finding contributes to the understanding of why most neurons in AD brain do not undergo apoptosis. Copyright © 2010. Published by Elsevier Inc.

QRS/T-wave and calcium alternans in a type I diabetic mouse model for spontaneous postmyocardial infarction ventricular tachycardia: A mechanism for the antiarrhythmic effect of statins.

PubMed

Jin, Hongwei; Welzig, Charles M; Aronovitz, Mark; Noubary, Farzad; Blanton, Robert; Wang, Bo; Rajab, Mohammad; Albano, Alfred; Link, Mark S; Noujaim, Sami F; Park, Ho-Jin; Galper, Jonas B

2017-09-01

The incidence of sudden arrhythmic death is markedly increased in diabetics. The purpose of this study was to develop a mouse model for postmyocardial infarction (post-MI) ventricular tachycardia (VT) in the diabetic heart and determine the mechanism of an antiarrhythmic effect of statins. ECG transmitters were implanted in wild-type (WT), placebo, and pravastatin-treated type I diabetic Akita mice. MIs were induced by coronary ligation, and Ca 2+ transients were studied by optical mapping, and Ca 2+ transients and sparks in left ventricular myocytes (VM) by the Ionoptix system and confocal microscopy. Burst pacing of Akita mouse hearts resulted in rate-related QRS/T-wave alternans, which was attenuated in pravastatin-treated mice. Post-MI Akita mice developed QRS/T-wave alternans and VT at 2820 ± 879 beats per mouse, which decreased to 343 ± 115 in pravastatin-treated mice (n = 13, P <.05). Optical mapping demonstrated pacing-induced VT originating in the peri-infarction zone and Ca 2+ alternans, both attenuated in hearts of statin-treated mice. Akita VM displayed Ca 2+ alternans, and triggered activity as well as increased Ca 2+ transient decay time (Tau), Ca 2+ sparks, and cytosolic Ca 2+ and decreased SR Ca 2+ stores all of which were in part reversed in cells from statin treated mice. Homogenates of Akita ventricles demonstrated decreased SERCA2a/PLB ratio and increased ratio of protein phosphatase (PP-1) to the PP-1 inhibitor PPI-1 which were reversed in homogenates of pravastatin-treated Akita mice. Pravastatin decreased the incidence of post-MI VT and Ca 2+ alternans in Akita mouse hearts in part by revering abnormalities of Ca 2+ handling via the PP-1/PPI-1 pathway. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Molecular Investigations of the Structure and Function of the Protein Phosphatase 1:Spinophilin:Inhibitor-2 Heterotrimeric Complex

PubMed Central

Dancheck, Barbara; Ragusa, Michael J.; Allaire, Marc; Nairn, Angus C.; Page, Rebecca; Peti, Wolfgang

2011-01-01

Regulation of the major ser/thr phosphatase Protein Phosphatase 1 (PP1) is controlled by a diverse array of targeting and inhibitor proteins. Though many PP1 regulatory proteins share at least one PP1 binding motif, usually the RVxF motif, it was recently discovered that certain pairs of targeting and inhibitor proteins bind PP1 simultaneously to form PP1 heterotrimeric complexes. To date, structural information for these heterotrimeric complexes, and, in turn, how they direct PP1 activity is entirely lacking. Using a combination of NMR spectroscopy, biochemistry and small angle X-ray scattering (SAXS), we show that major structural rearrangements in both spinophilin (targeting) and Inhibitor-2 (I-2, inhibitor) are essential for the formation of the heterotrimeric PP1:spinophilin:I-2 (PSI) complex. The RVxF motif of I-2 is released from PP1 during the formation of PSI, making the less prevalent SILK motif of I-2 essential for complex stability. The release of the I-2 RVxF motif allows for enhanced flexibility of both I-2 and spinophilin in the heterotrimeric complex. In addition, we used inductively coupled plasma atomic emission spectroscopy to show that PP1 contains two metals in both heterodimeric complexes (PP1:spinophilin and PP1:I2) and PSI, demonstrating that PSI retains the biochemical characteristics of the PP1:I2 holoenzyme. Finally, we combined the NMR and biochemical data with SAXS and molecular dynamics simulations to generate a structural model of the full heterotrimeric PSI complex. Collectively, these data reveal the molecular events that enable PP1 heterotrimeric complexes to exploit both the targeting and inhibitory features of the PP1-regulatory proteins to form multi-functional PP1 holoenzymes. PMID:21218781

Structure and function of the PP2A-shugoshin interaction

PubMed Central

Xu, Zheng; Cetin, Bulent; Anger, Martin; Cho, Uhn Soo; Helmhart, Wolfgang; Nasmyth, Kim; Xu, Wenqing

2009-01-01

SUMMARY Accurate chromosome segregation during mitosis and meiosis depends on shugoshin proteins that prevent precocious dissociation of cohesin from centromeres. Shugoshins associate with PP2A, which is thought to de-phosphorylate cohesin and thereby prevent cleavage by separase during meiosis I. A crystal structure of a complex between a fragment of human Sgo1 and an AB’C PP2A holoenzyme reveals that Sgo1 forms a homodimeric parallel coiled-coil that docks simultaneously onto PP2A’s C and B’ subunits. Sgo1 homo-dimerization is a pre-requisite for PP2A binding. While hSgo1 interacts only with the AB’C holoenzymes, its relative Sgo2 interacts with all PP2A forms and may thus lead to dephosphorylation of distinct substrates. Mutant shugoshin proteins defective in the binding of PP2A cannot protect centromeric cohesin from separase during meiosis I or support the spindle assembly checkpoint in yeast. Finally, we provide evidence that PP2A’s recruitment to chromosomes may be sufficient to protect cohesin from separase in mammalian oocytes. PMID:19716788

AIP1 recruits phosphatase PP2A to ASK1 in tumor necrosis factor-induced ASK1-JNK activation.

PubMed

Min, Wang; Lin, Yan; Tang, Shibo; Yu, Luyang; Zhang, Haifeng; Wan, Ting; Luhn, Tricia; Fu, Haian; Chen, Hong

2008-04-11

Previously we have shown that AIP1 (apoptosis signal-regulating kinase [ASK]1-interacting protein 1), a novel member of the Ras-GAP protein family, facilitates dephosphorylation of ASK1 at pSer967 and subsequently 14-3-3 release from ASK1, leading to enhanced ASK1-JNK signaling. However, the phosphatase(s) responsible for ASK1 dephosphorylation at pSer967 has not been identified. In the present study, we identified protein phosphatase (PP)2A as a potential phosphatase in vascular endothelial cells (ECs). Tumor necrosis factor (TNF)-induced dephosphorylation of ASK1 pSer967 in ECs was blocked by PP2A inhibitor okadaic acid. Overexpression of PP2A catalytic subunit induced dephosphorylation of ASK1 pSer967 and activation of c-Jun N-terminal kinase (JNK). In contrast, a catalytic inactive form of PP2A or PP2A small interfering RNA blunted TNF-induced dephosphorylation of ASK1 pSer967 and activation of JNK without effects on NF-kappaB activation. Whereas AIP1, via its C2 domain, binds to ASK1, PP2A binds to the GAP domain of AIP1. Endogenous AIP1-PP2A complex can be detected in the resting state, and TNF induces a complex formation of AIP1-PP2A with ASK1. Furthermore, TNF-induced association of PP2A with ASK1 was diminished in AIP1-knockdown ECs, suggesting a critical role of AIP1 in recruiting PP2A to ASK1. TNF-signaling molecules TRAF2 and RIP1, known to be in complex with AIP1 and activate AIP1 by phosphorylating AIP1 at Ser604, are critical for TNF-induced ASK1 dephosphorylation. Finally, PP2A and AIP1 cooperatively induce activation of ASK1-JNK signaling and EC apoptosis, as demonstrated by both overexpression and small interfering RNA knockdown approaches. Taken together, our data support a critical role of PP2A-AIP1 complex in TNF-induced activation of ASK1-JNK apoptotic signaling.

In vitro analysis of type II endoleaks and aneurysm sac pressurization on longitudinal stent-graft displacement.

PubMed

Knowles, Martyn; Pellisar, Tiago; Murphy, Erin H; Stanley, Gregory A; Hashmi, Abraham F; Arko, M Zachary; Arko, Frank R

2011-08-01

To evaluate the effects of type II endoleaks and sac pressurization on stent-graft displacement following endovascular aneurysm repair (EVAR). Experimental silicone infrarenal aneurysm (6-cm) models were "treated" with a Talent stent-graft deployed with 20-mm proximal and distal landing zones. Inflow and outflow vessels were created as part of the silicone model to control flow into the aneurysm sac. All aneurysm models were uniform, with a diameter neck of 31 mm, a neck length of 20 mm, and iliac artery diameters of 16 mm. The aortic model was secured in a water bath to a pulsatile pump under physiological conditions; the output phase ratio (%systole/%diastole) was set at 65/35 with a pump rate of 80 beats per minute. Commercially available bifurcated stent-grafts were then displaced in vitro utilizing a linear motion apparatus attached to a force gauge. The mean arterial pressure (MAP) and pulse pressure (PP) at the aortic inflow were 60.1 ± 3.1 and 38.3 ± 7.8 mmHg, respectively. Peak force to cause initial stent-graft migration with and without a type II endoleak was recorded and compared. In aneurysm sacs with no endoleak, the MAP and sac PP were 32 ± 6.4 and 6 ± 1.3 mmHg, respectively (p<0.01). In aneurysm sacs with a type II endoleak, the MAP and sac PP were 54.1 ± 9.7 and 16.1 ± 4.1 mmHg, respectively (p<0.02). Peak force to initiate migration was 16.0 ± 1.41 N (range 15-18) with no endoleak vs. 23.2 ± 2.2 N (range 20-25) in those with a type IIa endoleak and 23.5 ± 2.5 N (range 20-26) in those with a type IIb endoleak (p<0.001). Type II endoleaks are associated with a significantly increased sac pressure. Increased sac pressurization from type II endoleaks results in a significantly greater force to displace a stent-graft longitudinally. Type II endoleaks may therefore inhibit migration and offer a benefit following EVAR; however, clinical correlation of these results is required.

Interleukin (IL)-8 immunoreactivity of injured axons and surrounding oligodendrocytes in traumatic head injury.

PubMed

Hayashi, Takahito; Ago, Kazutoshi; Nakamae, Takuma; Higo, Eri; Ogata, Mamoru

2016-06-01

Interleukin (IL)-8 has been suggested to be a positive regulator of myelination in the central nervous system, in addition to its principal role as a chemokine for neutrophils. Immunostaining for beta-amyloid precursor protein (AβPP) is an effective tool for detecting traumatic axonal injury, although AβPP immunoreactivity can also indicate axonal injury due to hypoxic causes. In this study, we examined IL-8 and AβPP immunoreactivity in sections of corpus callosum obtained from deceased patients with blunt head injury and from equivalent control tissue. AβPP immunoreactivity was detected in injured axons, such as axonal bulbs and varicose axons, in 24 of 44 head injury cases. These AβPP immunoreactive cases had survived for more than 3h. The AβPP immunostaining pattern can be classified into two types: traumatic (Pattern 1) and non-traumatic (Pattern 2) axonal injuries, which we described previously [Hayashi et al. Int. J. Legal Med. 129 (2015) 1085-1090]. Three of 44 control cases also showed AβPP immunoreactive injured axons as Pattern 2. In contrast, IL-8 immunoreactivity was detected in 7 AβPP immunoreactive and in 2 non-AβPP immunoreactive head injury cases, but was not detected in any of the 44 control cases, including the 3 AβPP immunoreactive control cases. The IL-8 immunoreactive cases had survived from 3 to 24 days, whereas those cases who survived less than 3 days (n=29) and who survived 90 days (n=1) were not IL-8 immunoreactive. Moreover, IL-8 was detected as Pattern 1 axons only. In addition, double immunofluorescence analysis showed that IL-8 is expressed by oligodendrocytes surrounding injured axons. In conclusion, our results suggest that immunohistochemical detection of IL-8 may be useful as a complementary diagnostic marker of traumatic axonal injury. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dormancy-associated MADS-box genes and microRNAs jointly control dormancy transition in pear (Pyrus pyrifolia white pear group) flower bud

PubMed Central

Niu, Qingfeng; Li, Jianzhao; Cai, Danying; Qian, Minjie; Jia, Huimin; Bai, Songling; Hussain, Sayed; Liu, Guoqin; Teng, Yuanwen; Zheng, Xiaoyan

2016-01-01

Bud dormancy in perennial plants is indispensable to survival over winter and to regrowth and development in the following year. However, the molecular pathways of endo-dormancy induction, maintenance, and release are still unclear, especially in fruit crops. To identify genes with roles in regulating endo-dormancy, 30 MIKCC-type MADS-box genes were identified in the pear genome and characterized. The 30 genes were analysed to determine their phylogenetic relationships with homologous genes, genome locations, gene structure, tissue-specific transcript profiles, and transcriptional patterns during flower bud dormancy in ‘Suli’ pear (Pyrus pyrifolia white pear group). The roles in regulating bud dormancy varied among the MIKC gene family members. Yeast one-hybrid and transient assays showed that PpCBF enhanced PpDAM1 and PpDAM3 transcriptional activity during the induction of dormancy, probably by binding to the C-repeat/DRE binding site, while DAM proteins inhibited the transcriptional activity of PpFT2 during dormancy release. In the small RNA-seq analysis, 185 conserved, 24 less-conserved, and 32 pear-specific miRNAs with distinct expression patterns during bud dormancy were identified. Joint analyses of miRNAs and MIKC genes together with degradome data showed that miR6390 targeted PpDAM transcripts and degraded them to release PpFT2. Our data show that cross-talk among PpCBF, PpDAM, PpFT2, and miR6390 played important roles in regulating endo-dormancy. A model for the molecular mechanism of dormancy transition is proposed: short-term chilling in autumn activates the accumulation of CBF, which directly promotes DAM expression; DAM subsequently inhibits FT expression to induce endo-dormancy, and miR6390 degrades DAM genes to release endo-dormancy. PMID:26466664

Protein Phosphatase 2A Interacts with the Na+,K+-ATPase and Modulates Its Trafficking by Inhibition of Its Association with Arrestin

PubMed Central

Kimura, Toru; Han, WonSun; Pagel, Philipp; Nairn, Angus C.; Caplan, Michael J.

2011-01-01

Background The P-type ATPase family constitutes a collection of ion pumps that form phosphorylated intermediates during ion transport. One of the best known members of this family is the Na+,K+-ATPase. The catalytic subunit of the Na+,K+-ATPase includes several functional domains that determine its enzymatic and trafficking properties. Methodology/Principal Findings Using the yeast two-hybrid system we found that protein phosphatase 2A (PP2A) catalytic C-subunit is a specific Na+,K+-ATPase interacting protein. PP-2A C-subunit interacted with the Na+,K+-ATPase, but not with the homologous sequences of the H+,K+-ATPase. We confirmed that the Na+,K+-ATPase interacts with a complex of A- and C-subunits in native rat kidney. Arrestins and G-protein coupled receptor kinases (GRKs) are important regulators of G-protein coupled receptor (GPCR) signaling, and they also regulate Na+,K+-ATPase trafficking through direct association. PP2A inhibits association between the Na+,K+-ATPase and arrestin, and diminishes the effect of arrestin on Na+,K+-ATPase trafficking. GRK phosphorylates the Na+,K+-ATPase and PP2A can at least partially reverse this phosphorylation. Conclusions/Significance Taken together, these data demonstrate that the sodium pump belongs to a growing list of ion transport proteins that are regulated through direct interactions with the catalytic subunit of a protein phosphatase. PMID:22242112

Genetic and Developmental Analysis of Some New Color Mutants in the Goldfish, CARASSIUS AURATUS

PubMed Central

Kajishima, Takao

1977-01-01

The genotypes of three color mutants in goldfish: a depigmentation character of larval melanophores, albinism and a recessive-transparent character, were analyzed by crossing experiments. The depigmentation character in the common goldfish is controlled by two dominant multiple genes, Dp 1 and Dp2, and only fish with double recessive alleles dp1dp1 dp2dp2 can retain larval melanophores throughout life. Albinism is also controlled by double autosomal genes, p and c. The genotype of an albino fish is represented by pp cc; the non-albino fish is PP CC. Fish with either a pp CC or pp Cc genotype are albino when scored at the time of melanosome differentiation in the pigment retina, but after the time of skin melanophore differentiation, they change to the nonalbino type under the control of the C gene. The recessive-transparent character is controlled by a single autosomal gene, g. The mechanisms of gene expression of these characters were proposed as a result of observation and/or experimental data on the differentiation processes of their phenotypes, and the genotypes of these color mutant goldfish were considered in relation to the "gene duplication hypothesis in the Cyprinidae." PMID:885340

Eosinophils are required to suppress Th2 responses in Peyer's patches during intestinal infection by nematodes.

PubMed

Strandmark, J; Steinfelder, S; Berek, C; Kühl, A A; Rausch, S; Hartmann, S

2017-05-01

Infections with enteric nematodes result in systemic type 2 helper T (Th2) responses, expansion of immunoglobulin (Ig)G1 antibodies, and eosinophilia. Eosinophils have a supportive role in mucosal Th2 induction during airway hyperreactivity. Whether eosinophils affect the local T-cell and antibody response in the gut-associated lymphoid tissue during enteric infections is unknown. We infected eosinophil-deficient ΔdblGATA-1 mice with the Th2-inducing small intestinal nematode Heligmosomoides polygyrus and found that parasite fecundity was decreased in the absence of eosinophils. A lack of eosinophils resulted in significantly augmented expression of GATA-3 and IL-4 by CD4 + T cells during acute infection, a finding strictly limited to Peyer's patches (PP). The increase in IL-4-producing cells in ΔdblGATA-1 mice was particularly evident within the CXCR5 + PD-1 + T-follicular helper cell population and was associated with a switch of germinal centre B cells to IgG1 production and elevated serum IgG1 levels. In contrast, infected wild-type mice had a modest IgG1 response in the PP, whereas successfully maintaining a population of IgA + germinal center B cells. Our results suggest a novel role for eosinophils during intestinal infection whereby they restrict IL-4 responses by follicular T helper cells and IgG1 class switching in the PP to ensure maintenance of local IgA production.

Isolation of lactobacillus reuteri from Peyer's patches and their effects on sIgA production and gut microbiota diversity.

PubMed

Wang, Panpan; Li, Ya; Xiao, Hang; Shi, Yonghui; Le, Guo-Wei; Sun, Jin

2016-09-01

We previously reported that specific Lactobacillus reuteri colonized within mouse Peyer's patches (PP) effectively prevented high fat diet induced obesity and low-grade chronic inflammation. We further investigated the role of PP Lactobacillus reuteri on sIgA production in rats in this study. Lactobacilli were isolated from rat PP. All isolates were L. reuteri and belonged to three phenotypes according to amplified fragment length polymorphism analysis. Typical strains of two main clusters, PP1 and PP2, were used to treat control and vitamin A deficient (VAD) rats, respectively. The feeding of PP1 and PP2 affected sIgA and Lactobacillus diversity by strain-specific manner. Free sIgA was significantly increased by PP1 (p = 0.069) and PP2 (p < 0.05) in the control rats but not in the VAD rats. Only PP1 significantly changed PP Lactobacillus diversity in the control rats (p < 0.05). However, PP2 specifically changed ileal Lactobacillus diversity in both control and VAD rats. Fecal sIgA was correlated with PP Lactobacillus diversity (R(2) = 0.7958, p = 0.011). Modulation of sIgA production by PP L. reuteri of rat is dependent on vitamin A and change of Lactobacillus diversity in PP. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural Basis for the Catalytic Activity of Human Serine/Threonine Protein Phosphatase-5

NASA Technical Reports Server (NTRS)

Swingle, M. R.; Honkanen, R.; Ciszak, E. M.

2004-01-01

Serinehhreonine protein phosphatase-5 (PP5) affects many signaling networks that regulate cell growth and cellular responses to stress. Here we report the crystal structure of the PP5 catalytic domain (PP5c) at a resolution of 1.6 A. From this structure we resolved the mechanism for PP5-mediated hydrolysis of phosphoprotein substrates, which requires the precise positioning of two metal ions within a con served Aspn-271-M(sub 1):M(sub 2)-W(sup 1)-His-427-His-304-Asp-274 catalytic motif. The structure of PPSc provides a structural basis for explaining the exceptional catalytic proficiency of protein phosphatases, which are among the most powerful known catalysts. Resolution of the entire C-terminus revealed a novel subdomain, and the structure of the PP5c should also aid development of type-specific inhibitors.

Effect of atmospheric oxidative plasma treatments on polypropylenic fibers surface: Characterization and reaction mechanisms

NASA Astrophysics Data System (ADS)

Nisticò, Roberto; Magnacca, Giuliana; Faga, Maria Giulia; Gautier, Giovanna; D'Angelo, Domenico; Ciancio, Emanuele; Lamberti, Roberta; Martorana, Selanna

2013-08-01

Atmospheric pressure plasma-dielectric barrier discharge (APP-DBD, open chamber configuration) was used to functionalize polypropylene (PP) fibers surface in order to generate oxidized-reactive groups such as hydroperoxides, alcohols and carbonyl species (i.e. ketones and others). Such a species increased the surface polarity, without causing material degradation. Three different types of plasma mixture (He, He/O2, He/O2/H2O) under three different values of applied power (750, 1050, 1400 W) were investigated. The formed plasma species (O2+, O single atom and OH radical) and their distribution were monitored via optical emission spectrometry (OES) measurements, and the plasma effects on PP surface species formation were followed by X-ray photoemission spectroscopy (XPS). Results allowed to better understand the reaction pathways between plasma phase and PP fibers. In fact, two reaction mechanisms were proposed, the first one concerning the plasma phase reactions and the second one involving material surface modifications.

Ultrafast plasmon-enhanced hot electron process in model heterojunctions: Ag/TiO2 and Ag/graphite

NASA Astrophysics Data System (ADS)

Petek, Hrvoje

We study the plasmonically enhanced nonlinear photoemission from Ag nanocluster-decorated graphite and TiO2(110) surfaces by time-resolved two-photon photoemission spectroscopy (TR-2PP). Evaporating Ag atoms on graphite and TiO2 surfaces forms pancake-like Ag clusters with 5 nm diameter and 1-1.5 nm height through self-limiting growth mode. The Ag nanoparticles enhance the two-photon photoemission (2PP) signal by approximately two-orders of magnitude as compared with the bare surfaces for p-polarized excitation. In the case of s-polarization there is essentially no enhancement for graphite, and only about an order-of-magnitude enhancement for TiO2. Wavelength dependent measurements of the enhancement reveal that for Ag/graphite there is a single plasmonic resonance due to the ⊥-plasmon mode at 3.6 eV. By contrast, for Ag/TiO2 there are ⊥ and ||-plasmon modes with resonant energies of 3.8 and 3.1 eV, respectively. Apparently the dielectric properties of the substrate have strong influence on the type and frequency of Ag plasmonic modes that can exist on the surfaces. 2PP spectra of the Ag/graphite and Ag/TiO2 surfaces reveal two distinct components that are common to both. The high energy component consists of a coherent 2PP process from an occupied interface state, which only exists in the presence of Ag. We identify this state, as an interface state formed by charge donation from the Ag-5s band to the unoccupied states of the substrates. The low energy component consists of a hot electron signal that is created by plasmon dephasing. TR-2PP measurements are performed on the plasmon-induced electron dynamics to assess their relevance for plasmonically enhanced femtochemistry. This research was supported by NSF Grant CHE-1414466.

Intracellular uptake and behavior of two types zinc protoporphyrin (ZnPP) micelles, SMA-ZnPP and PEG-ZnPP as anticancer agents; unique intracellular disintegration of SMA micelles.

PubMed

Nakamura, Hideaki; Fang, Jun; Gahininath, Bharate; Tsukigawa, Kenji; Maeda, Hiroshi

2011-11-07

SMA-ZnPP and PEG-ZnPP are micellar drugs, encapsulating zinc protoporphyrin IX (ZnPP) with styrene maleic acid copolymer (SMA) and covalent conjugate of ZnPP with polyethylene glycol (PEG) respectively. Their intracellular uptake rate and subcellular localization were investigated. We found SMA-ZnPP showed higher and more efficient (about 2.5 times) intracellular uptake rate than PEG-ZnPP, although both SMA-ZnPP and PEG-ZnPP micelles were localized at endoplasmic reticulum (ER) and inhibited the target enzyme heme oxygenase 1 (HO-1) similarly. Both micellar ZnPP were taken up into the tumor cells by endocytosis. Furthermore SMA-ZnPP and PEG-ZnPP were examined for their drug releasing mechanisms. Liberation of ZnPP from the SMA micelle appears to depend on cellular amphiphilic components such as lecithin, while that for PEG-ZnPP depends on hydrolytic cleavage. These results indicate that these micelle formulations make water insoluble ZnPP to water soluble practical anticancer agents. Copyright © 2011 Elsevier B.V. All rights reserved.

Characterization of Phlebotomus papatasi peritrophins, and the role of PpPer1 in Leishmania major survival in its natural vector.

PubMed

Coutinho-Abreu, Iliano V; Sharma, Narinder K; Robles-Murguia, Maricela; Ramalho-Ortigao, Marcelo

2013-01-01

The peritrophic matrix (PM) plays a key role in compartmentalization of the blood meal and as barrier to pathogens in many disease vectors. To establish an infection in sand flies, Leishmania must escape from the endoperitrophic space to prevent excretion with remnants of the blood meal digestion. In spite of the role played regarding Leishmania survival, little is known about sand fly PM molecular components and structural organization. We characterized three peritrophins (PpPer1, PpPer2, and PpPer3) from Phlebotomus papatasi. PpPer1 and PpPer2 display, respectively, four and one chitin-binding domains (CBDs). PpPer3 on the other hand has two CBDs, one mucin-like domain, and a putative domain with hallmarks of a CBD, but with changes in key amino acids. Temporal and spatial expression analyses show that PpPer1 is expressed specifically in the female midgut after blood feeding. PpPer2 and PpPer3 mRNAs were constitutively expressed in midgut and hindgut, with PpPer3 also being expressed in Malpighian tubules. PpPer2 was the only gene expressed in developmental stages. Interestingly, PpPer1 and PpPer3 expression are regulated by Le. major infection. Recombinant PpPer1, PpPer2 and PpPer3 were obtained and shown to display similar biochemical profiles as the native; we also show that PpPer1 and PpPer2 are able to bind chitin. Knockdown of PpPer1 led to a 44% reduction in protein, which in spite of producing an effect on the percentage of infected sand flies, resulted in a 39% increase of parasite load at 48 h. Our data suggest that PpPer1 is a component for the P. papatasi PM and likely involved in the PM role as barrier against Le. major infection.

Inhibition of AMP Kinase by the Protein Phosphatase 2A Heterotrimer, PP2APpp2r2d*

PubMed Central

Joseph, Biny K.; Liu, Hsing-Yin; Francisco, Jamie; Pandya, Devanshi; Donigan, Melissa; Gallo-Ebert, Christina; Giordano, Caroline; Bata, Adam; Nickels, Joseph T.

2015-01-01

AMP kinase is a heterotrimeric serine/threonine protein kinase that regulates a number of metabolic processes, including lipid biosynthesis and metabolism. AMP kinase activity is regulated by phosphorylation, and the kinases involved have been uncovered. The particular phosphatases counteracting these kinases remain elusive. Here we discovered that the protein phosphatase 2A heterotrimer, PP2APpp2r2d, regulates the phosphorylation state of AMP kinase by dephosphorylating Thr-172, a residue that activates kinase activity when phosphorylated. Co-immunoprecipitation and co-localization studies indicated that PP2APpp2r2d directly interacted with AMP kinase. PP2APpp2r2d dephosphorylated Thr-172 in rat aortic and human vascular smooth muscle cells. A positive correlation existed between decreased phosphorylation, decreased acetyl-CoA carboxylase Acc1 phosphorylation, and sterol response element-binding protein 1c-dependent gene expression. PP2APpp2r2d protein expression was up-regulated in the aortas of mice fed a high fat diet, and the increased expression correlated with increased blood lipid levels. Finally, we found that the aortas of mice fed a high fat diet had decreased AMP kinase Thr-172 phosphorylation, and contained an Ampk-PP2APpp2r2d complex. Thus, PP2APpp2r2d may antagonize the aortic AMP kinase activity necessary for maintaining normal aortic lipid metabolism. Inhibiting PP2APpp2r2d or activating AMP kinase represents a potential pharmacological treatment for many lipid-related diseases. PMID:25694423

The Psen1-L166P-knock-in mutation leads to amyloid deposition in human wild-type amyloid precursor protein YAC transgenic mice

PubMed Central

Vidal, Ruben; Sammeta, Neeraja; Garringer, Holly J.; Sambamurti, Kumar; Miravalle, Leticia; Lamb, Bruce T.; Ghetti, Bernardino

2012-01-01

Genetically engineered mice have been generated to model cerebral β-amyloidosis, one of the hallmarks of Alzheimer disease (AD) pathology, based on the overexpression of a mutated cDNA of the amyloid-β precursor protein (AβPP) or by knock-in of the murine Aβpp gene alone or with presenilin1 mutations. Here we describe the generation and initial characterization of a new mouse line based on the presence of 2 copies of the human genomic region encoding the wild-type AβPP and the L166P presenilin 1 mutation. At ∼6 mo of age, double-mutant mice develop amyloid pathology, with signs of neuritic dystrophy, intracellular Aβ accumulation, and glial inflammation, an increase in AβPP C-terminal fragments, and an 8 times increase in Aβ42 levels with a 40% decrease in Aβ40 levels, leading to a significant increase (14 times) of Aβ42/Aβ40 ratios, with minimal effects on presenilin or the Notch1 pathway in the brain. We conclude that in mice, neither mutations in AβPP nor overexpression of an AβPP isoform are a prerequisite for Aβ pathology. This model will allow the study of AD pathogenesis and testing of therapeutic strategies in a more relevant environment without experimental artifacts due to the overexpression of a single-mutant AβPP isoform using exogenous promoters.—Vidal, R., Sammeta, N., Garringer, H. J., Sambamurti, K., Miravalle, L., Lamb B. T., Ghetti, B. The Psen1-L166P-knock-in mutation leads to amyloid deposition in human wild-type amyloid precursor protein YAC transgenic mice. PMID:22459153

Foot deformities, function in the lower extremities, and plantar pressure in patients with diabetes at high risk to develop foot ulcers

PubMed Central

Tang, Ulla Hellstrand; Zügner, Roland; Lisovskaja, Vera; Karlsson, Jon; Hagberg, Kerstin; Tranberg, Roy

2015-01-01

Objective Foot deformities, neuropathy, and dysfunction in the lower extremities are known risk factors that increase plantar peak pressure (PP) and, as a result, the risk of developing foot ulcers in patients with diabetes. However, knowledge about the prevalence of these factors is still limited. The aim of the present study was to describe the prevalence of risk factors observed in patients with diabetes without foot ulcers and to explore possible connections between the risk factors and high plantar pressure. Patients and methods Patients diagnosed with type 1 (n=27) or type 2 (n=47) diabetes (mean age 60.0±15.0 years) were included in this cross-sectional study. Assessments included the registration of foot deformities; test of gross function at the hip, knee, and ankle joints; a stratification of the risk of developing foot ulcers according to the Swedish National Diabetes Register; a walking test; and self-reported questionnaires including the SF-36 health survey. In-shoe PP was measured in seven regions of interests on the sole of the foot using F-Scan®. An exploratory analysis of the association of risk factors with PP was performed. Results Neuropathy was present in 28 (38%), and 39 (53%) had callosities in the heel region. Low forefoot arch was present in 57 (77%). Gait-related parameters, such as the ability to walk on the forefoot or heel, were normal in all patients. Eighty percent had normal function at the hip and ankle joints. Gait velocity was 1.2±0.2 m/s. All patients were stratified to risk group 3. Hallux valgus and hallux rigidus were associated with an increase in the PP in the medial forefoot. A higher body mass index (BMI) was found to increase the PP at metatarsal heads 4 and 5. Pes planus was associated with a decrease in PP at metatarsal head 1. Neuropathy did not have a high association with PP. Conclusions This study identified several potential risk factors for the onset of diabetic foot ulcers (DFU). Hallux valgus and hallux rigidus appeared to increase the PP under the medial forefoot and a high BMI appeared to increase the PP under the lateral forefoot. There is a need to construct a simple, valid, and reliable assessment routine to detect potential risk factors for the onset of DFU. PMID:26087865

Psychoses in epilepsy: A comparison of postictal and interictal psychoses.

PubMed

Hilger, Eva; Zimprich, Friedrich; Pataraia, Ekaterina; Aull-Watschinger, Susanne; Jung, Rebekka; Baumgartner, Christoph; Bonelli, Silvia

2016-07-01

We retrospectively analyzed data of patients with epilepsy (n=1434) evaluated with prolonged EEG monitoring in order to estimate the prevalence of postictal psychosis (PP) and interictal psychosis (IP), to investigate a potential association of psychosis subtype with epilepsy type, and to assess differences between PP and IP. The overall prevalence of psychosis was 5.9% (N=85); prevalence of PP (N=53) and IP (N=32) was 3.7% and 2.2%, respectively. Of patients with psychosis, 97.6% had localization-related epilepsy (LRE). Prevalence of psychosis was highest (9.3%) in patients with temporal lobe epilepsy (TLE). When comparing PP with IP groups on demographic, clinical, and psychopathological variables, patients with IP were younger at occurrence of first psychosis (P=0.048), had a shorter interval between epilepsy onset and first psychosis (P=0.002), and more frequently exhibited schizophreniform traits (conceptual disorganization: P=0.008; negative symptoms: P=0.017) than those with PP. Postictal psychosis was significantly associated with a temporal seizure onset on ictal EEG (P=0.000) and a higher incidence of violent behavior during psychosis (P=0.047). To conclude, our results support the presumption of a preponderance of LRE in patients with psychosis and that of a specific association of TLE with psychosis, in particular with PP. Given the significant differences between groups, PP and IP may represent distinct clinical entities potentially with a different neurobiological background. Copyright © 2016 Elsevier Inc. All rights reserved.

Involvement of the K+-Cl- co-transporter KCC2 in the sensitization to morphine-induced hyperlocomotion under chronic treatment with zolpidem in the mesolimbic system.

PubMed

Shibasaki, Masahiro; Masukawa, Daiki; Ishii, Kazunori; Yamagishi, Yui; Mori, Tomohisa; Suzuki, Tsutomu

2013-06-01

Benzodiazepines are commonly used as sedatives, sleeping aids, and anti-anxiety drugs. However, chronic treatment with benzodiazepines is known to induce dependence, which is considered related to neuroplastic changes in the mesolimbic system. This study investigated the involvement of K(+) -Cl(-) co-transporter 2 (KCC2) in the sensitization to morphine-induced hyperlocomotion after chronic treatment with zolpidem [a selective agonist of γ-aminobutyric acid A-type receptor (GABAA R) α1 subunit]. In this study, chronic treatment with zolpidem enhanced morphine-induced hyperlocomotion, which is accompanied by the up-regulation of KCC2 in the limbic forebrain. We also found that chronic treatment with zolpidem induced the down-regulation of protein phosphatase-1 (PP-1) as well as the up-regulation of phosphorylated protein kinase C γ (pPKCγ). Furthermore, PP-1 directly associated with KCC2 and pPKCγ, whereas pPKCγ did not associate with KCC2. On the other hand, pre-treatment with furosemide (a KCC2 inhibitor) suppressed the enhancing effects of zolpidem on morphine-induced hyperlocomotion. These results suggest that the mesolimbic dopaminergic system could be amenable to neuroplastic change through a pPKCγ-PP-1-KCC2 pathway by chronic treatment with zolpidem. © 2013 International Society for Neurochemistry.

Patient derived mutation W257G of PPP2R1A enhances cancer cell migration through SRC-JNK-c-Jun pathway

PubMed Central

Jeong, Ae Lee; Han, Sora; Lee, Sunyi; Su Park, Jeong; Lu, Yiling; Yu, Shuangxing; Li, Jane; Chun, Kyung-Hee; Mills, Gordon B.; Yang, Young

2016-01-01

Mutation of PPP2R1A has been observed at high frequency in endometrial serous carcinomas but at low frequency in ovarian clear cell carcinoma. However, the biological role of mutation of PPP2R1A in ovarian and endometrial cancer progression remains unclear. In this study, we found that PPP2R1A expression is elevated in high-grade primary tumor patients with papillary serous tumors of the ovary. To determine whether increased levels or mutation of PPP2R1A might contribute to cancer progression, the effects of overexpression or mutation of PPP2R1A on cell proliferation, migration, and PP2A phosphatase activity were investigated using ovarian and endometrial cancer cell lines. Among the mutations, PPP2R1A-W257G enhanced cell migration in vitro through activating SRC-JNK-c-Jun pathway. Overexpression of wild type (WT) PPP2R1A increased its binding ability with B56 regulatory subunits, whereas PPP2R1A-mutations lost the ability to bind to most B56 subunits except B56δ. Total PP2A activity and PPP2R1A-associated PP2Ac activity were significantly increased in cells overexpressing PPP2R1A-WT. In addition, overexpression of PPP2R1A-WT increased cell proliferation in vitro and tumor growth in vivo. PMID:27272709

Differential effects on cell motility, embryonic stem cell self-renewal and senescence by diverse Src kinase family inhibitors

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

Tamm, Christoffer, E-mail: christoffer.tamm@imbim.uu.se; Galito, Sara Pijuan, E-mail: sara.pijuan@imbim.uu.se; Anneren, Cecilia, E-mail: cecilia.anneren@imbim.uu.se

2012-02-15

The Src family of non-receptor tyrosine kinases (SFKs) has been shown to play an intricate role in embryonic stem (ES) cell maintenance. In the present study we have focused on the underlying molecular mechanisms responsible for the vastly different effects induced by various commonly used SFK inhibitors. We show that several diverse cell types, including fibroblasts completely lacking SFKs, cannot undergo mitosis in response to SU6656 and that this is caused by an unselective inhibition of Aurora kinases. In contrast, PP2 and PD173952 block motility immediately upon exposure and forces cells to grow in dense colonies. The subsequent halt inmore » proliferation of fibroblast and epithelial cells in the center of the colonies approximately 24 h post-treatment appears to be caused by cell-to-cell contact inhibition rather than a direct effect of SFK kinase inhibition. Interestingly, in addition to generating more homogenous and dense ES cell cultures, without any diverse effect on proliferation, PP2 and PD173652 also promote ES cell self-renewal by reducing the small amount of spontaneous differentiation typically observed under standard ES cell culture conditions. These effects could not be mirrored by the use of Gleevec, a potent inhibitor of c-Abl and PDGFR kinases that are also inhibited by PP2. -- Highlights: Black-Right-Pointing-Pointer SFK inhibitor SU6656 induces senescence in mouse ES cells. Black-Right-Pointing-Pointer SU6656 inhibits mitosis in a SFK-independent manner via cross-selectivity for Aurora kinases. Black-Right-Pointing-Pointer SFK inhibitor PP2 impairs cell motility in various cell lines, including mouse ES cells. Black-Right-Pointing-Pointer Ensuing impeded motility, PP2 inhibits proliferation of various cells lines except for mouse ES cells. Black-Right-Pointing-Pointer SFK inhibitors PP2 and PD173952 impede spontaneous differentiation in standard mouse ES culture maintenance.« less

Downregulation of protein phosphatase 2A carboxyl methylation and methyltransferase may contribute to Alzheimer disease pathogenesis.

PubMed

Sontag, Estelle; Hladik, Christa; Montgomery, Lisa; Luangpirom, Ampa; Mudrak, Ingrid; Ogris, Egon; White, Charles L

2004-10-01

ABalphaC, a major protein phosphatase 2A (PP2A) heterotrimeric enzyme, binds to and regulates the microtubule cytoskeleton and tau. We have shown that ABalphaC protein expression levels are selectively reduced in Alzheimer disease (AD). Notably, the carboxyl methylation of PP2A catalytic subunit (PP2A(C)) is critically required for ABalphaC holoenzyme assembly, and catalyzed by a specific methyltransferase (PPMT). Here, we provide the first analysis of human PPMT and methylated PP2A(C) in brain regions from AD, non-AD demented, and aged control autopsy cases. Immunoblotting analyses revealed that PPMT protein expression and PP2A(C) methylation levels were quantitatively decreased in AD-affected brain regions. Immunohistochemical studies showed that PPMT was abundant in neurons throughout the cortex in normal control and non-AD demented cases. However, in AD, there was a regional loss of PPMT immunoreactivity that closely paralleled the severity of tau pathology, but not amyloid plaque burden. We propose that the deregulation of PPMT and PP2A methylation/demethylation cycles contributes to AD pathogenesis, by inducing changes in PP2A heteromultimeric composition and substrate specificity. In turn, PP2A dysfunction compromises the mechanisms that control tau, neuronal plasticity, and survival.

Studies on the control of development: isolation of Bacillus subtilis mutants blocked early in sporulation and defective in synthesis of highly phosphorylated nucleotides.

PubMed

Rhaese, H J; Hoch, J A; Groscurth, R

1977-03-01

To test our model on the mechanism of initiation of differentiation in Bacillus subtilis, we tested early blocked (stage 0) sporulation mutants for their ability to synthesize highly phosphorylated nucleotides. We also isolated early blocked asporogenous mutants with the aid of the intercalating drug tilorone. Among all mutants tested we found that the spo0F-bearing strain was unable to synthesize adenosine 3'(2')-triphosphate 5'-triphosphate, pppAppp. A revertant of this mutant regained the ability to both sporulate and synthesize pppAppp. Ribosomes of the asporogenous mutant isolated at T2 (2 hr after the end of logarithmic growth) of sporulation, in contrast to the wild type, do not synthesize adenosine 3'(2')-diphosphate 5'-diphosphate, ppApp, or adenosine 3'(2')-diphosphate 5'-triphosphate, pppApp, but synthesize guanosine 3'(2')-diphosphate 5'-diphosphate, ppGpp, and guanosine 3'(2')-diphosphate 5'-triphosphate, pppGpp. This behavior is characteristic of ribosomes from vegetative, not sporulating, cells. Ribosomes from the sporogenous revertant behave like those of the wild type. The results suggest that the spo0F mutation may be a mutation in the structural gene for pppAppp synthetase. The inability to synthesize pppAppp in this strain also prevents the formation of "sporulation-specific ribosomes," i.e., ribosomes that synthetize ppApp and pppApp. The present experiments suggest that the nucleotide pppAppp participates in the initiation of sporulation by triggering a sequencies of events required for the production of heat-resistant spores.

DATATOC: a novel conjugate for kit-type 68Ga labelling of TOC at ambient temperature.

PubMed

Seemann, Johanna; Waldron, Bradley; Parker, David; Roesch, Frank

2017-01-01

The widespread acceptance and application of 68 Ga-PET depends on our ability to develop radiopharmaceuticals that can be prepared in a convenient and suitable manner. A kit-type labelling protocol provides such characteristics and requires chelators that can be radiolabelled under exceptionally mild conditions. Recently the DATA chelators have been introduced that fulfil these requirements. In continuing their development, the synthesis and radiolabelling of the first DATA bifunctional chelator (BFC) and peptide conjugate are described. A BFC derived from the DATA ligand (2,2'-(6-((carboxymethyl)amino)-1,4-diazepane-1,4-diyl)diacetic acid) has been synthesised in five steps from simple building blocks, with an overall yield of 8 %. DATA M5 -3 t Bu (5-[1,4-Bis-tert-butoxycarbonylmethyl-6-(tert-butoxycarbonylmethyl-methyl-amino)-[1, 4]diazepan-6-yl]-pentanoic acid) has been coupled to [DPhe 1 ][Tyr 3 ]-octreotide (TOC) and the resulting peptide conjugate (DATATOC) radiolabelled with purified 68 Ga derived via four different 68 Ge/ 68 Ga generator post-processing (PP) methods. The stability and lipophilicity of the radiotracer have been assessed and a kit-type formulation for radiolabelling evaluated. 68 Ga-DATATOC has been prepared with a > 95 % radiochemical yield (RCY) within 1 (fractionated and acetone-PP) and 10 min (ethanol- and NaCl-PP) at 23 °C (pH 4.2-4.9, 13 nmol). The radiolabelled peptide is stable in the presence of human serum. Lipophilicity of 68 Ga-DATATOC was calculated as logP = -3.2 ± 0.3, with a HPLC retention time ( t R  = 10.4 min) similar to 68 Ga-DOTATOC (logP = -2.9 ± 0.4, t R  = 10.3 min). Kit-type labelling from a lyophilised solid using acetone-PP based labelling achieves > 95 % RCY in 10 min at 23 °C. The favourable labelling properties of the DATA chelators have been retained for DATATOC. High radiochemical purity can be achieved at 23 °C in less than 1 min and from a kit formulation. The speed, reliability, ease, flexibility and simplicity with which 68 Ga-DATATOC can be prepared makes it a very attractive alternative to current standards.

PP2ARts1 is a master regulator of pathways that control cell size

PubMed Central

Zapata, Jessica; Dephoure, Noah; MacDonough, Tracy; Yu, Yaxin; Parnell, Emily J.; Mooring, Meghan; Gygi, Steven P.; Stillman, David J.

2014-01-01

Cell size checkpoints ensure that passage through G1 and mitosis occurs only when sufficient growth has occurred. The mechanisms by which these checkpoints work are largely unknown. PP2A associated with the Rts1 regulatory subunit (PP2ARts1) is required for cell size control in budding yeast, but the relevant targets are unknown. In this paper, we used quantitative proteome-wide mass spectrometry to identify proteins controlled by PP2ARts1. This revealed that PP2ARts1 controls the two key checkpoint pathways thought to regulate the cell cycle in response to cell growth. To investigate the role of PP2ARts1 in these pathways, we focused on the Ace2 transcription factor, which is thought to delay cell cycle entry by repressing transcription of the G1 cyclin CLN3. Diverse experiments suggest that PP2ARts1 promotes cell cycle entry by inhibiting the repressor functions of Ace2. We hypothesize that control of Ace2 by PP2ARts1 plays a role in mechanisms that link G1 cyclin accumulation to cell growth. PMID:24493588

Control of seed dormancy and germination by DOG1-AHG1 PP2C phosphatase complex via binding to heme.

PubMed

Nishimura, Noriyuki; Tsuchiya, Wataru; Moresco, James J; Hayashi, Yuki; Satoh, Kouji; Kaiwa, Nahomi; Irisa, Tomoko; Kinoshita, Toshinori; Schroeder, Julian I; Yates, John R; Hirayama, Takashi; Yamazaki, Toshimasa

2018-06-06

Abscisic acid (ABA) regulates abiotic stress and developmental responses including regulation of seed dormancy to prevent seeds from germinating under unfavorable environmental conditions. ABA HYPERSENSITIVE GERMINATION1 (AHG1) encoding a type 2C protein phosphatase (PP2C) is a central negative regulator of ABA response in germination; however, the molecular function and regulation of AHG1 remain elusive. Here we report that AHG1 interacts with DELAY OF GERMINATION1 (DOG1), which is a pivotal positive regulator in seed dormancy. DOG1 acts upstream of AHG1 and impairs the PP2C activity of AHG1 in vitro. Furthermore, DOG1 has the ability to bind heme. Binding of DOG1 to AHG1 and heme are independent processes, but both are essential for DOG1 function in vivo. Our study demonstrates that AHG1 and DOG1 constitute an important regulatory system for seed dormancy and germination by integrating multiple environmental signals, in parallel with the PYL/RCAR ABA receptor-mediated regulatory system.

Mechanisms for Antagonistic Regulation of AMPA and NMDA-D1 Receptor Complexes at Postsynaptic Sites

NASA Technical Reports Server (NTRS)

Schumann, Johann; Scheler, Gabriele

2004-01-01

From the analysis of these pathways we conclude that postsynaptic processes that regulate synaptic transmission undergo significant cross-talk with respect to glutamatergic and neuromodulatory (dopamine) signals. The main hypothesis is that of a compensatory regulation, a competitive switch between the induction of increased AMPA conductance by CaMKII-dependent phosphorylation and reduced expression of PP2A, and increased D1 receptor sensitivity and expression by increased PKA, PP2A and decreased PP-1/calcineurin expression. Both types of plasticity are induced by NMDA receptor activation and increased internal calcium, they require different internal conditions to become expressed. Specifically we propose that AMPA regulation and D1 regulation are inversely coupled;The net result may be a bifurcation of synaptic state into predominantly AMPA or NMDA-D1 synapses. This could have functional consequences: stable connections for AMPA and conditional gating for NMDA-D1 synapses.

Enhanced ethylene responsiveness in the Arabidopsis eer1 mutant results from a loss-of-function mutation in the protein phosphatase 2A A regulatory subunit, RCN1.

PubMed

Larsen, Paul Brian; Cancel, Jesse Daniel

2003-06-01

Ethylene signaling in Arabidopsis begins with a family of five ethylene receptors that regulate the activity of the Raf-like kinase, CTR1. Recent work to identify novel factors required for modulating ethylene signaling resulted in the isolation of enhanced ethylene response 1 (eer1), a mutant that displays both increased sensitivity and increased amplitude of response to ethylene. Molecular cloning of eer1 reveals that its mutant phenotype results from a loss-of-function mutation in the previously characterized RCN1, one of three PP2A A regulatory subunits in Arabidopsis. Our analysis shows that neither RCN1 expression nor PP2A activity is regulated by ethylene. Instead, we found that Arabidopsis PP2A-1C, a PP2A catalytic subunit previously characterized as interacting with RCN1, associates strongly with the kinase domain of CTR1 in vitro. This likely represents a role for PP2A in modulation of CTR1 activity because an in vitro kinase assay did not reveal phosphorylation of either RCN1 or PP2A-1C by CTR1, indicating that neither of them is a substrate for CTR1. PP2A activity is required for Ras-dependent activation of mammalian Raf, with reductions in PP2A activity significantly compromising the effectiveness of this mechanism. Our genetic and biochemical results suggest that a similar requirement for PP2A activity exists for ethylene signaling, with loss-of-function mutations affecting PP2A activity possibly reducing the effectiveness of CTR1 activation, thus lowering the threshold required for manifestation of ethylene response.

Effect of cyclical thermal to mechanical properties of Hybrid Laminate Composites (HLC) with skin recycle polypropylene/natural fiber/halloysite and core PP/KF composites

NASA Astrophysics Data System (ADS)

Sri Suharty, Neng; Ismail, Hanafi; Suci Handayani, Desi; Diharjo, Kuncoro; Rachman Wibowo, Fajar; Arnita Wuri, Margaretha

2016-02-01

This research has successfully synthesized six hybrid laminate composites (HLC). These HLC consist of two layers skin composites and one layer of core PP/KF composites. There are sticked with epoxy adhesive by using cold press method. In this research 6 types of skin are used, namely the rPP (recycled polypropylene, HC1); rPP/DVB/PP-g-AA/KF (HC2); rPP/DVB/PP-g-AA/Hall (HC3); rPP/DVB/PP-g-AA/Hall+ZB (HC4); rPP/DVB/PP-g-AA/KF/Hall (HC5) and rPP/DVB/PP-g-AA/KF/Hall+ZB (HC6) composites. The mechanical properties assessment tensile strength (TS) of various HLC before and after cyclical thermal (CT) was done by ASTM D638. While testing the flame retardant: such as time to ignition (TTI) and burning rate (BR) was done by ASTM D635. Heat stability of HLC can be recognized by conducting the CT treatment. It is to determine the effect of fluctuating heat loads on mechanical properties of HLC materials. The TS result of five HLCs (HC2, HC3, HC4, HC5 and HC6) before CT treatment were higher than HC1 (blank HLC). Those five HLC are also able to increase the TTI and reduce the BR compared to HC1. The CT treatment conditions performed at 45 oC as much as 125 times. After CT treatment, the TS values only slightly decline compared to before CT treatment.

Developmental and light regulation of tumor suppressor protein PP2A in the retina

PubMed Central

Rajala, Ammaji; Wang, Yuhong; Abcouwer, Steven F.; Gardner, Thomas W.; Rajala, Raju V.S.

2018-01-01

Protein phosphatases are a group of universal enzymes that are responsible for the dephosphorylation of various proteins and enzymes in cells. Cellular signal transduction events are largely governed by the phosphorylation of key proteins. The length of cellular response depends on the activation of protein phosphatase that dephosphorylates the phosphate groups to halt a biological response, and fine-tune the defined cellular outcome. Dysregulation of these phosphatase(s) results in various disease phenotypes. The retina is a post-mitotic tissue, and oncogenic tyrosine and serine/ threonine kinase activities are important for retinal neuron survival. Aberrant activation of protein phosphatase(s) may have a negative effect on retinal neurons. In the current study, we characterized tumor suppressor protein phosphatase 2 (PP2A), a major serine/ threonine kinase with a broad substrate specificity. Our data suggest that PP2A is developmentally regulated in the retina, localized predominantly in the inner retina, and expressed in photoreceptor inner segments. Our findings indicate that PKCα and mTOR may serve as PP2A substrates. We found that light regulates PP2A activity. Our studies also suggest that rhodopsin regulates PP2A and its substrate(s) dephosphorylation. PP2A substrate phosphorylation is increased in mice lacking the A-subunit of PP2A. However, there is no accompanying effect on retina structure and function. Together, our findings suggest that controlling the activity of PP2A in the retina may be neuroprotective. PMID:29416710

Protein phosphatase 2A associates with and regulates atypical PKC and the epithelial tight junction complex

PubMed Central

Nunbhakdi-Craig, Viyada; Machleidt, Thomas; Ogris, Egon; Bellotto, Dennis; White, Charles L.; Sontag, Estelle

2002-01-01

Tight junctions (TJs) play a crucial role in the establishment of cell polarity and regulation of paracellular permeability in epithelia. Here, we show that upon calcium-induced junction biogenesis in Madin-Darby canine kidney cells, ABαC, a major protein phosphatase (PP)2A holoenzyme, is recruited to the apical membrane where it interacts with the TJ complex. Enhanced PP2A activity induces dephosphorylation of the TJ proteins, ZO-1, occludin, and claudin-1, and is associated with increased paracellular permeability. Expression of PP2A catalytic subunit severely prevents TJ assembly. Conversely, inhibition of PP2A by okadaic acid promotes the phosphorylation and recruitment of ZO-1, occludin, and claudin-1 to the TJ during junctional biogenesis. PP2A negatively regulates TJ assembly without appreciably affecting the organization of F-actin and E-cadherin. Significantly, inhibition of atypical PKC (aPKC) blocks the calcium- and serum-independent membrane redistribution of TJ proteins induced by okadaic acid. Indeed, PP2A associates with and critically regulates the activity and distribution of aPKC during TJ formation. Thus, we provide the first evidence for calcium-dependent targeting of PP2A in epithelial cells, we identify PP2A as the first serine/threonine phosphatase associated with the multiprotein TJ complex, and we unveil a novel role for PP2A in the regulation of epithelial aPKC and TJ assembly and function. PMID:12196510

The ‘spiteful’ origins of human cooperation

PubMed Central

Marlowe, Frank W.; Berbesque, J. Colette; Barrett, Clark; Bolyanatz, Alexander; Gurven, Michael; Tracer, David

2011-01-01

We analyse generosity, second-party (‘spiteful’) punishment (2PP), and third-party (‘altruistic’) punishment (3PP) in a cross-cultural experimental economics project. We show that smaller societies are less generous in the Dictator Game but no less prone to 2PP in the Ultimatum Game. We might assume people everywhere would be more willing to punish someone who hurt them directly (2PP) than someone who hurt an anonymous third person (3PP). While this is true of small societies, people in large societies are actually more likely to engage in 3PP than 2PP. Strong reciprocity, including generous offers and 3PP, exists mostly in large, complex societies that face numerous challenging collective action problems. We argue that ‘spiteful’ 2PP, motivated by the basic emotion of anger, is more universal than 3PP and sufficient to explain the origins of human cooperation. PMID:21159680

The 'spiteful' origins of human cooperation.

PubMed

Marlowe, Frank W; Berbesque, J Colette; Barrett, Clark; Bolyanatz, Alexander; Gurven, Michael; Tracer, David

2011-07-22

We analyse generosity, second-party ('spiteful') punishment (2PP), and third-party ('altruistic') punishment (3PP) in a cross-cultural experimental economics project. We show that smaller societies are less generous in the Dictator Game but no less prone to 2PP in the Ultimatum Game. We might assume people everywhere would be more willing to punish someone who hurt them directly (2PP) than someone who hurt an anonymous third person (3PP). While this is true of small societies, people in large societies are actually more likely to engage in 3PP than 2PP. Strong reciprocity, including generous offers and 3PP, exists mostly in large, complex societies that face numerous challenging collective action problems. We argue that 'spiteful' 2PP, motivated by the basic emotion of anger, is more universal than 3PP and sufficient to explain the origins of human cooperation.

Efficacy of dietary spray dried plasma protein to mitigate the negative effects on performance of pigs fed diets with corn naturally contaminated with multiple mycotoxins.

PubMed

Weaver, A C; Campbell, J M; Crenshaw, J D; Polo, J; Kim, S W

2014-09-01

The ability of spray dried plasma protein (SDPP) to reduce the negative effects of multiple mycotoxins from naturally contaminated corn on weaned pig performance and health was investigated (n = 180; 6.84 ± 0.11 kg). For 12 d after weaning, pigs were fed phase 1 nursery diets with either 0% SDPP (PP0) or 6% SDPP (PP6). After 12 d, pigs were fed phase 2 diets for 3 wk. Pigs fed PP0 in phase 1 continued to be fed a phase 2 diet with no SDPP (PP0/PP0) or were fed a diet including corn naturally contaminated with multiple mycotoxins (M), labeled PP0/PP0M. Pigs fed SDPP in phase 1 were fed either a diet with no SDPP (PP6/PP0), a diet with M and no SDPP (PP6/PP0M), a diet with M and 3% SDPP (PP6/PP3M), or a diet with M and 6% SDPP (PP6/PP6M). During phase 1, pigs fed PP6 had increased (P < 0.05) ADG, ADFI, and G:F, whereas immunological parameters were not altered. During phase 2, pigs consuming PP0/PP0M had reduced ADG (P < 0.01) and ADFI (P < 0.05) in contrast to pigs fed PP0/PP0, whereas the performance of pigs fed PP6/PP0M was intermediate to pigs fed PP0/PP0M and PP6/PP0. The ADG and ADFI did not differ for pigs fed PP0/PP0M and PP6/PP0M during phase 2. Performance of pigs fed PP6/PP3M in contrast to pigs fed PP6/PP0M during phase 2 did not differ; however, these pigs had lower (P < 0.05) tumor necrosis factor α and tended (P = 0.094) to have lower DNA damage. During phase 2, ADG and ADFI of pigs fed PP6/PP6M did not differ from pigs fed PP6/PP0M, but G:F tended (P = 0.067) to be increased in pigs fed PP6/PP6M. Over the entire study period, pigs fed PP0/PP0M had reduced (P < 0.05) ADG and tended (P = 0.067) to have reduced ADFI. During this time, pigs fed PP6/PP0M tended to have greater ADG and ADFI (P = 0.093 and P = 0.067, respectively) compared with pigs fed PP0/PP0M. Overall, feeding a diet with SDPP improved growth performance and feed intake of young pigs directly after weaning. Feeding multiple M had a negative impact on growth performance of pigs during this trial. This response was more significant when pigs were not fed SDPP in phase 1. Overall, when combining phase 1 and 2 performance data, daily gain and feed intake tended to be reduced when pigs were not fed 6% SDPP in phase 1. This study indicates that the composition of diets fed immediately after weaning may be important for pigs that subsequently are under a M challenge.

Overexpression of PP2A-C5 that encodes the catalytic subunit 5 of protein phosphatase 2A in Arabidopsis confers better root and shoot development under salt conditions

USDA-ARS?s Scientific Manuscript database

Protein phosphatase 2A (PP2A) is an enzyme consisting of three subunits: a scaffolding A subunit, a regulatory B subunit and a catalytic C subunit. PP2As were shown to play diverse roles in eukaryotes. In this study, the function of the Arabidopsis PP2A-C5 gene that encodes the catalytic subunit 5 o...

PP2A regulates SCF-induced cardiac stem cell migration through interaction with p38 MAPK.

PubMed

Wang, Ying; Xia, Yanli; Kuang, Dong; Duan, Yaqi; Wang, Guoping

2017-12-15

Previous studies have shown that stem cell factor (SCF) induces the migration of cardiac stem cells (CSCs) and helps to repair myocardial infarctions. Earlier studies on the migration mechanism only focused on the activation of kinases; here, we aimed to explore the functional role of protein phosphatase 2A (PP2A) in SCF-induced CSC migration. CSCs were treated with SCF, PP2A enzymatic activity was measured, the phosphorylation levels of PP2A, p38 MAPK and cofilin were evaluated using western blot. Transwell assay was used to determine the migratory ability of CSCs. In vitro, SCF induced the phosphorylation of p38 MAPK and cofilin, leading to the migration of CSCs. Cofilin acted as a downstream signal of p38 MAPK. PP2A was involved in this process. Further studies revealed that PP2A was inactivated via phosphorylation at Tyr307 by SCF and the inactivation/phosphorylation was mediated by activated p38 MAPK, as p38 MAPK inhibitor SB203580 or siRNA prevented SCF-induced inactivation and phosphorylation of PP2A. When CSCs were pretreated with PP2A inhibitor (okadaic acid, OA), SCF-induced CSC migration and the downstream signals were enhanced, and the enhancement was reversed when p38 MAPK was blocked. Additionally, co-immunoprecipitation showed a direct interaction of PP2A with p38 MAPK. Our results indicated that PP2A regulated the SCF-induced activation of p38 MAPK/cofilin signaling pathway and subsequent migration of CSCs by interaction with p38 MAPK. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Structural Basis of PP2A Inhibition by Small t Antigen

PubMed Central

Cho, Uhn Soo; Morrone, Seamus; Sablina, Anna A; Arroyo, Jason D; Hahn, William C; Xu, Wenqing

2007-01-01

The SV40 small t antigen (ST) is a potent oncoprotein that perturbs the function of protein phosphatase 2A (PP2A). ST directly interacts with the PP2A scaffolding A subunit and alters PP2A activity by displacing regulatory B subunits from the A subunit. We have determined the crystal structure of full-length ST in complex with PP2A A subunit at 3.1 Å resolution. ST consists of an N-terminal J domain and a C-terminal unique domain that contains two zinc-binding motifs. Both the J domain and second zinc-binding motif interact with the intra-HEAT-repeat loops of HEAT repeats 3–7 of the A subunit, which overlaps with the binding site of the PP2A B56 subunit. Intriguingly, the first zinc-binding motif is in a position that may allow it to directly interact with and inhibit the phosphatase activity of the PP2A catalytic C subunit. These observations provide a structural basis for understanding the oncogenic functions of ST. PMID:17608567

Mutations in a new Arabidopsis cyclophilin disrupt its interaction with protein phosphatase 2A

NASA Technical Reports Server (NTRS)

Jackson, K.; Soll, D.; Evans, M. L. (Principal Investigator)

1999-01-01

The heterotrimeric protein phosphatase 2A (PP2A) is a component of multiple signaling pathways in eukaryotes. Disruption of PP2A activity in Arabidopsis is known to alter auxin transport and growth response pathways. We demonstrated that the regulatory subunit A of an Arabidopsis PP2A interacts with a novel cyclophilin, ROC7. The gene for this cyclophilin encodes a protein that contains a unique 30-amino acid extension at the N-terminus, which distinguishes the gene product from all previously identified Arabidopsis cyclophilins. Altered forms of ROC7 cyclophilin with mutations in the conserved DENFKL domain did not bind to PP2A. Unlike protein phosphatase 2B, PP2A activity in Arabidopsis extracts was not affected by the presence of the cyclophilin-binding molecule cyclosporin. The ROC7 transcript was expressed to high levels in all tissues tested. Expression of an ROC7 antisense transcript gave rise to increased root growth. These results indicate that cyclophilin may have a role in regulating PP2A activity, by a mechanism that differs from that employed for cyclophilin regulation of PP2B.

Gravitropism of Arabidopsis thaliana roots requires the polarization of PIN2 toward the root tip in meristematic cortical cells.

PubMed

Rahman, Abidur; Takahashi, Maho; Shibasaki, Kyohei; Wu, Shuang; Inaba, Takehito; Tsurumi, Seiji; Baskin, Tobias I

2010-06-01

In the root, the transport of auxin from the tip to the elongation zone, referred to here as shootward, governs gravitropic bending. Shootward polar auxin transport, and hence gravitropism, depends on the polar deployment of the PIN-FORMED auxin efflux carrier PIN2. In Arabidopsis thaliana, PIN2 has the expected shootward localization in epidermis and lateral root cap; however, this carrier is localized toward the root tip (rootward) in cortical cells of the meristem, a deployment whose function is enigmatic. We use pharmacological and genetic tools to cause a shootward relocation of PIN2 in meristematic cortical cells without detectably altering PIN2 polarization in other cell types or PIN1 polarization. This relocation of cortical PIN2 was negatively regulated by the membrane trafficking factor GNOM and by the regulatory A1 subunit of type 2-A protein phosphatase (PP2AA1) but did not require the PINOID protein kinase. When GNOM was inhibited, PINOID abundance increased and PP2AA1 was partially immobilized, indicating both proteins are subject to GNOM-dependent regulation. Shootward PIN2 specifically in the cortex was accompanied by enhanced shootward polar auxin transport and by diminished gravitropism. These results demonstrate that auxin flow in the root cortex is important for optimal gravitropic response.

ABCG2 transporter inhibitor restores the sensitivity of triple negative breast cancer cells to aminolevulinic acid-mediated photodynamic therapy.

PubMed

Palasuberniam, Pratheeba; Yang, Xue; Kraus, Daniel; Jones, Patrick; Myers, Kenneth A; Chen, Bin

2015-08-18

Photosensitizer protoporphyrin IX (PpIX) fluorescence, intracellular localization and cell response to photodynamic therapy (PDT) were analyzed in MCF10A normal breast epithelial cells and a panel of human breast cancer cells including estrogen receptor (ER) positive, human epidermal growth factor receptor 2 (HER2) positive and triple negative breast cancer (TNBC) cells after treatment with PpIX precursor aminolevulinic acid (ALA). Although PpIX fluorescence was heterogeneous in different cells, TNBC cells showed significantly lower PpIX level than MCF10A and ER- or HER2-positive cells. PpIX fluorescence in TNBC cells also had much less mitochondrial localization than other cells. There was an inverse correlation between PpIX fluorescence and cell viability after PDT. Breast cancer cells with the highest PpIX fluorescence were the most sensitive to ALA-PDT and TNBC cells with the lowest PpIX level were resistant to PDT. Treatment of TNBC cells with ABCG2 transporter inhibitor Ko143 significantly increased ALA-PpIX fluorescence, enhanced PpIX mitochondrial accumulation and sensitized cancer cells to ALA-PDT. Ko143 treatment had little effect on PpIX production and ALA-PDT in normal and ER- or HER2-positive cells. These results demonstrate that enhanced ABCG2 activity renders TNBC cell resistance to ALA-PDT and inhibiting ABCG2 transporter is a promising approach for targeting TNBC with ALA-based modality.

An extract of Urtica dioica L. mitigates obesity induced insulin resistance in mice skeletal muscle via protein phosphatase 2A (PP2A).

PubMed

Obanda, Diana N; Ribnicky, David; Yu, Yongmei; Stephens, Jacqueline; Cefalu, William T

2016-02-26

The leaf extract of Urtica dioica L. (UT) has been reported to improve glucose homeostasis in vivo, but definitive studies on efficacy and mechanism of action are lacking. We investigated the effects of UT on obesity- induced insulin resistance in skeletal muscle. Male C57BL/6J mice were divided into three groups: low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with UT. Body weight, body composition, plasma glucose and plasma insulin were monitored. Skeletal muscle (gastrocnemius) was analyzed for insulin sensitivity, ceramide accumulation and the post translational modification and activity of protein phosphatase 2A (PP2A). PP2A is activated by ceramides and dephosphorylates Akt. C2C12 myotubes exposed to excess free fatty acids with or without UT were also evaluated for insulin signaling and modulation of PP2A. The HFD induced insulin resistance, increased fasting plasma glucose, enhanced ceramide accumulation and PP2A activity in skeletal muscle. Supplementation with UT improved plasma glucose homeostasis and enhanced skeletal muscle insulin sensitivity without affecting body weight and body composition. In myotubes, UT attenuated the ability of FFAs to induce insulin resistance and PP2A hyperactivity without affecting ceramide accumulation and PP2A expression. UT decreased PP2A activity through posttranslational modification that was accompanied by a reduction in Akt dephosphorylation.

Template properties of oligocytidylates formed in the montmorillonite catalyzed condensation of ImpC. [Abstract only

NASA Technical Reports Server (NTRS)

Ferris, James P.; Ertem, Goezen

1994-01-01

In an attempt to investigate the prebiotic formation of phosphodiester bond in RNA, we have studied the self condensation of 5'-phosphorimidazolide of adenosine (ImpA), in aqueous solutions containing 0.2 M sodium chloride and 0.075 M magnesium chloride at pH 8 using clay minerals as catalyst. In the presence of certain montmorillonites, oligomers containing up to ten monomer units in their chain were formed, while in control experiments, where no catalyst was added, the major product was 5',5'-diadenosine diphosphate, A(sup 5')ppA. In reactions carried out with ImpA: A(sup 5')ppA mixtures at 9:1 mole ratio, oligomers of the type A(sup 5')p(pA)(sub n) and (A(sup 5')p)(sub n)A(sup 5')ppA(pA)(sub n) formed at the expense of (pA)(sub n) type oligomers. Addition of A(sup 5')ppA to the reaction mixture increased the regiospecifity of 3',5'-link formation from 67% to 79%. The condensation of the 5'-phosphorimidazolide of cytidine, ImpC, was also carried out in the presence and absence of A(sup 5')ppA under the same conditions and oligomers containing up to twelve monomer units were obtained.

Cloning and expression profiling of the PacSnRK2 and PacPP2C gene families during fruit development, ABA treatment, and dehydration stress in sweet cherry.

PubMed

Shen, Xinjie; Guo, Xiao; Zhao, Di; Zhang, Qiang; Jiang, Yuzhuang; Wang, Yantao; Peng, Xiang; Wei, Yan; Zhai, Zefeng; Zhao, Wei; Li, Tianhong

2017-10-01

Plant SNF1-related protein kinase 2 (SnRK2) and protein phosphatase 2C (PP2C) family members are core components of the ABA signal transduction pathway. SnRK2 and PP2C proteins have been suggested to play crucial roles in fruit ripening and improving plant tolerance to drought stress, but supporting genetic information has been lacking in sweet cherry (Prunus avium L.). Here, we cloned six full-length SnRK2 genes and three full-length PP2C genes from sweet cherry cv. Hong Deng. Quantitative PCR analysis revealed that PacSnRK2.2, PacSnRK2.3, PacSnRK2.6, and PacPP2C1-3 were negatively regulated in fruits in response to exogenous ABA treatment, PacSnRK2.4 and PacSnRK2.5 were upregulated, and PacSnRK2.1 expression was not affected. The ABA treatment also significantly promoted the accumulation of anthocyanins in sweet cherry fruit. The expression of all PacSnRK2 and PacPP2C genes was induced by dehydration stress, which also promoted the accumulation of drought stress signaling molecules in the sweet cherry fruits, including ABA, soluble sugars, and anthocyanin. Furthermore, a yeast two-hybrid analysis demonstrated that PacPP2C1 interacts with all six PacSnRK2s, while PacPP2C3 does not interact with PacSnRK2.5. PacPP2C2 does not interact with PacSnRK2.1 or PacSnRK2.4. These results indicate that PacSnRK2s and PacPP2Cs may play a variety of roles in the sweet cherry ABA signaling pathway and the fruit response to drought stress. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The crystal structure of an inverting glycoside hydrolase family 9 exo-β-D-glucosaminidase and the design of glycosynthase.

PubMed

Honda, Yuji; Arai, Sachiko; Suzuki, Kentaro; Kitaoka, Motomitsu; Fushinobu, Shinya

2016-02-15

Exo-β-D-glucosaminidase (EC 3.2.1.165) from Photobacterium profundum (PpGlcNase) is an inverting GH (glycoside hydrolase) belonging to family 9. We have determined the three-dimensional structure of PpGlcNase to describe the first structure-function relationship of an exo-type GH9 glycosidase. PpGlcNase has a narrow and straight active-site pocket, in contrast with the long glycan-binding cleft of a GH9 endoglucanase. This is because PpGlcNase has a long loop, which blocks the position corresponding to subsites -4 to -2 of the endoglucanase. The pocket shape of PpGlcNase explains its substrate preference for a β1,4-linkage at the non-reducing terminus. Asp(139), Asp(143) and Glu(555) in the active site were located near the β-O1 hydroxy group of GlcN (D-glucosamine), with Asp(139) and Asp(143) holding a nucleophilic water molecule for hydrolysis. The D139A, D143A and E555A mutants significantly decreased hydrolytic activity, indicating their essential role. Of these mutants, D139A exclusively exhibited glycosynthase activity using α-GlcN-F (α-D-glucosaminyl fluoride) and GlcN as substrates, to produce (GlcN)2. Using saturation mutagenesis at Asp(139), we obtained D139E as the best glycosynthase. Compared with the wild-type, the hydrolytic activity of D139E was significantly suppressed (<0.1%), and the F(-)-release activity also decreased (<3%). Therefore the glycosynthase activity of D139E was lower than that of glycosynthases created previously from other inverting GHs. Mutation at the nucleophilic water holder is a general strategy for creating an effective glycosynthase from inverting GHs. However, for GH9, where two acidic residues seem to share the catalytic base role, mutation of Asp(139) might inevitably reduce F(-)-release activity. © 2016 Authors; published by Portland Press Limited.

Regulatory Subunit B′γ of Protein Phosphatase 2A Prevents Unnecessary Defense Reactions under Low Light in Arabidopsis1[W][OA

PubMed Central

Trotta, Andrea; Wrzaczek, Michael; Scharte, Judith; Tikkanen, Mikko; Konert, Grzegorz; Rahikainen, Moona; Holmström, Maija; Hiltunen, Hanna-Maija; Rips, Stephan; Sipari, Nina; Mulo, Paula; Weis, Engelbert; von Schaewen, Antje; Aro, Eva-Mari; Kangasjärvi, Saijaliisa

2011-01-01

Light is an important environmental factor that modulates acclimation strategies and defense responses in plants. We explored the functional role of the regulatory subunit B′γ (B′γ) of protein phosphatase 2A (PP2A) in light-dependent stress responses of Arabidopsis (Arabidopsis thaliana). The predominant form of PP2A consists of catalytic subunit C, scaffold subunit A, and highly variable regulatory subunit B, which determines the substrate specificity of PP2A holoenzymes. Mutant leaves of knockdown pp2a-b′γ plants show disintegration of chloroplasts and premature yellowing conditionally under moderate light intensity. The cell-death phenotype is accompanied by the accumulation of hydrogen peroxide through a pathway that requires CONSTITUTIVE EXPRESSION OF PR GENES5 (CPR5). Moreover, the pp2a-b′γ cpr5 double mutant additionally displays growth suppression and malformed trichomes. Similar to cpr5, the pp2a-b′γ mutant shows constitutive activation of both salicylic acid- and jasmonic acid-dependent defense pathways. In contrast to cpr5, however, pp2a-b′γ leaves do not contain increased levels of salicylic acid or jasmonic acid. Rather, the constitutive defense response associates with hypomethylation of DNA and increased levels of methionine-salvage pathway components in pp2a-b′γ leaves. We suggest that the specific B′γ subunit of PP2A is functionally connected to CPR5 and operates in the basal repression of defense responses under low irradiance. PMID:21571669

Transcriptional regulation of genes encoding ABA metabolism enzymes during the fruit development and dehydration stress of pear 'Gold Nijisseiki'.

PubMed

Dai, Shengjie; Li, Ping; Chen, Pei; Li, Qian; Pei, Yuelin; He, Suihuan; Sun, Yufei; Wang, Ya; Kai, Wenbin; Zhao, Bo; Liao, Yalan; Leng, Ping

2014-09-01

To investigate the contribution of abscisic acid (ABA) in pear 'Gold Nijisseiki' during fruit ripening and under dehydration stress, two cDNAs (PpNCED1 and PpNCED2) which encode 9-cis-epoxycarotenoid dioxygenase (NCED) (a key enzyme in ABA biosynthesis), two cDNAs (PpCYP707A1 and PpCYP707A2) which encode 8'-hydroxylase (a key enzyme in the oxidative catabolism of ABA), one cDNA (PpACS3) which encodes 1-aminocyclopropane-1-carboxylic acid (ACC), and one cDNA (PpACO1) which encodes ACC oxidase involved in ethylene biosynthesis were cloned from 'Gold Nijisseiki' fruit. In the pulp, peel and seed, expressions of PpNCED1 and PpNCED2 rose in two stages which corresponded with the increase of ABA levels. The expression of PpCYP707A1 dramatically declined after 60-90 days after full bloom (DAFB) in contrast to the changes of ABA levels during this period, while PpCYP707A2 stayed low during the whole development of fruit. Application of exogenous ABA at 100 DAFB increased the soluble sugar content and the ethylene release but significantly decreased the titratable acid and chlorophyll contents in fruits. When fruits harvested at 100 DAFB were stored in the laboratory (25 °C, 50% relative humidity), the ABA content and the expressions of PpNCED1/2 and PpCYP707A1 in the pulp, peel and seed increased significantly, while ethylene reached its highest value after the maximum peak of ABA accompanied with the expressions of PpACS3 and PpACO1. In sum the endogenous ABA may play an important role in the fruit ripening and dehydration of pear 'Gold Nijisseiki' and the ABA level was regulated mainly by the dynamics of PpNCED1, PpNCED2 and PpCYP707A1 at the transcriptional level. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The PP2AB56 phosphatase promotes the association of Cdc20 with APC/C in mitosis.

PubMed

Lee, Sun Joo; Rodriguez-Bravo, Veronica; Kim, Hyunjung; Datta, Sutirtha; Foley, Emily A

2017-05-15

PP2A comprising B56 regulatory subunit isoforms (PP2A B56 ) is a serine/threonine phosphatase essential for mitosis. At the kinetochore, PP2A B56 both stabilizes microtubule binding and promotes silencing of the spindle assembly checkpoint (SAC) through its association with the SAC protein BubR1. Cells depleted of the B56 regulatory subunits of PP2A are delayed in activation of Cdc20-containing APC/C (APC/C Cdc20 ), which is an essential step for mitotic exit. It has been hypothesized that this delay arises from increased production of the mitotic checkpoint complex (MCC), an APC/C Cdc20 inhibitor formed at unattached kinetochores through SAC signaling. In contrast to this prediction, we show that depletion of B56 subunits does not increase the amount or stability of the MCC. Rather, delays in APC/C Cdc20 activation in B56-depleted cells correlate with impaired Cdc20 binding to APC/C. Stimulation of APC/C Cdc20 assembly does not require binding between PP2A B56 and BubR1, and thus this contribution of PP2A B56 towards mitotic exit is distinct from its functions at kinetochores. PP2A B56 associates with APC/C constitutively in a BubR1-independent manner. A mitotic phosphorylation site on Cdc20, known to be a substrate of PP2A B56 , modulates APC/C Cdc20 assembly. These results elucidate the contributions of PP2A B56 towards completion of mitosis. © 2017. Published by The Company of Biologists Ltd.

A SABATH Methyltransferase from the moss Physcomitrella patens catalyzes

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

Zhao, Nan; Ferrer, Jean-Luc; Moon, Hong S

2012-01-01

Known SABATH methyltransferases, all of which were identified from seed plants, catalyze methylation of either the carboxyl group of a variety of low molecular weight metabolites or the nitrogen moiety of precursors of caffeine. In this study, the SABATH family from the bryophyte Physcomitrella patens was identified and characterized. Four SABATH-like sequences (PpSABATH1, PpSABATH2, PpSABATH3, and PpSABATH4) were identified from the P. patens genome. Only PpSABATH1 and PpSABATH2 showed expression in the leafy gametophyte of P. patens. Full-length cDNAs of PpSABATH1 and PpSABATH2 were cloned and expressed in soluble form in Escherichia coli. Recombinant PpSABATH1 and PpSABATH2 were tested formore » methyltransferase activity with a total of 75 compounds. While showing no activity with carboxylic acids or nitrogen-containing compounds, PpSABATH1 displayed methyltransferase activity with a number of thiols. PpSABATH2 did not show activity with any of the compounds tested. Among the thiols analyzed, PpSABATH1 showed the highest level of activity with thiobenzoic acid with an apparent Km value of 95.5 lM, which is comparable to those of known SABATHs. Using thiobenzoic acid as substrate, GC MS analysis indicated that the methylation catalyzed by PpSABATH1 is on the sulfur atom. The mechanism for S-methylation of thiols catalyzed by PpSABATH1 was partially revealed by homology-based structural modeling. The expression of PpSABATH1 was induced by the treatment of thiobenzoic acid. Further transgenic studies showed that tobacco plants overexpressing PpSABATH1 exhibited enhanced tolerance to thiobenzoic acid, suggesting that PpSABATH1 have a role in the detoxification of xenobiotic thiols.« less

Integrated Cognitive-neuroscience Architectures for Understanding Sensemaking (ICArUS): Phase 2 Test and Evaluation Development Guide

DTIC Science & Technology

2014-11-01

location, based on the evidence provided in Datum ( OSINT , IMINT, and the BLUEBOOK). The targetSum and normalizationConstraint attributes indicate that the...34LessThanOrEqualTo" id="Pp" name="P(Attack | IMINT, OSINT )" type="AttackProbabilityReport_Pp"> <Datum locationId=ŕ-1" datumType=" OSINT ...AttackProbabilityProbe_Ppc targetSum=蔴.0" normalizationConstraint="LessThanOrEqualTo" id="Ppc" name="P(Attack | HUMINT, IMINT, OSINT )" type

Abscisic Acid (ABA ) Promotes the Induction and Maintenance of Pear (Pyrus pyrifolia White Pear Group) Flower Bud Endodormancy

PubMed Central

Li, Jianzhao; Xu, Ying; Niu, Qingfeng; He, Lufang; Teng, Yuanwen; Bai, Songling

2018-01-01

Dormancy is an adaptive mechanism that allows temperate deciduous plants to survive unfavorable winter conditions. In the present work, we investigated the possible function of abscisic acid (ABA) on the endodormancy process in pear. The ABA content increased during pear flower bud endodormancy establishment and decreased towards endodormancy release. In total, 39 putative genes related to ABA metabolism and signal transductions were identified from pear genome. During the para- to endodormancy transition, PpNCED-2 and PpNCED-3 had high expression levels, while PpCYP707As expression levels were low. However, during endodormancy, the expression of PpCYP707A-3 sharply increased with increasing cold accumulation. At the same time, the ABA content of pear buds declined, and the percentage of bud breaks rapidly increased. On the other hand, the expression levels of PpPYLs, PpPP2Cs, PpSnRK2s, and PpABI4/ABI5s were also changed during the pear flower bud dormancy cycle. Furthermore, exogenous ABA application to para-dormant buds significantly reduced the bud breaks and accelerated the transition to endodormancy. During the whole treatment time, the expression level of PpPP2C-12 decreased to a greater extent in ABA-treated buds than in control. However, the expression levels of PpSnRK2-1, PpSnRK2-4, and PpABI5-1 were higher in ABA-treated buds. Our results indicated that PpCYP707A-3 and PpNCEDs play pivotal roles on the regulation of endodormancy release, while ABA signal transduction pathway also appears to be involved in the process. The present work provided the basic information about the function of ABA-related genes during pear flower bud dormancy process. PMID:29361708

Amphipathic Polyproline Peptides Stimulate Cholesterol Efflux by the ABCA1 Transporter

PubMed Central

Sviridov, D.O.; Drake, S.K.; Freeman, L.A.; Remaley, A.T.

2016-01-01

ApoA-I mimetics are short synthetic peptides that contain an amphipathic αα-helix and stimulate cholesterol efflux by the ABCA1 transporter in a detergent-like extraction mechanism. We investigated the use of amphipathic peptides with a polypro helix for stimulating cholesterol efflux by ABCA1. Polypro peptides were synthesized with modified prolines, containing either a hydrophobic phenol group (Prop) or a polar N-acetylgalactosamine (Prog) attached to the pyrrolidine ring and were designated as either PP-2, 3, 4, or 5, depending on the number of 3 amino acid repeat units (Prop - Prog - Prop). Based on molecular modeling, these peptides were predicted to be relatively rigid and to bind to a phospholipid bilayer. By CD spectroscopy, PP peptides formed a Type-II polypro helix in an aqueous solution. PP-2 was inactive in promoting cholesterol efflux, but peptides with more than 2 repeat units were active. PP-4 showed a similar Vmax as a much longer amphipathic α-αhelical peptide, containing 37 amino acids, but had a Km that was approximately 20-fold lower. PP peptides were specific in that they did not stimulate cholesterol efflux from cells not expressing ABCA1 and were also non-cytotoxic. Addition of PP-3, 4 and 5 to serum promoted the formation of smaller size HDL species (7 nM) and increased its capacity for ABCA1-dependent cholesterol efflux by approximately 20-35% (p<0.05). Because of their relatively small size and increased potency, amphipathic peptides with a polypro helix may represent an alternative structural motif for the development of apoA-I mimetic peptides. PMID:26879139

An extract of Urtica dioica L. mitigates obesity induced insulin resistance in mice skeletal muscle via protein phosphatase 2A (PP2A)

PubMed Central

Obanda, Diana N.; Ribnicky, David; Yu, Yongmei; Stephens, Jacqueline; Cefalu, William T.

2016-01-01

The leaf extract of Urtica dioica L. (UT) has been reported to improve glucose homeostasis in vivo, but definitive studies on efficacy and mechanism of action are lacking. We investigated the effects of UT on obesity- induced insulin resistance in skeletal muscle. Male C57BL/6J mice were divided into three groups: low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with UT. Body weight, body composition, plasma glucose and plasma insulin were monitored. Skeletal muscle (gastrocnemius) was analyzed for insulin sensitivity, ceramide accumulation and the post translational modification and activity of protein phosphatase 2A (PP2A). PP2A is activated by ceramides and dephosphorylates Akt. C2C12 myotubes exposed to excess free fatty acids with or without UT were also evaluated for insulin signaling and modulation of PP2A. The HFD induced insulin resistance, increased fasting plasma glucose, enhanced ceramide accumulation and PP2A activity in skeletal muscle. Supplementation with UT improved plasma glucose homeostasis and enhanced skeletal muscle insulin sensitivity without affecting body weight and body composition. In myotubes, UT attenuated the ability of FFAs to induce insulin resistance and PP2A hyperactivity without affecting ceramide accumulation and PP2A expression. UT decreased PP2A activity through posttranslational modification that was accompanied by a reduction in Akt dephosphorylation. PMID:26916435

Ferulic Acid Attenuates the Injury-Induced Decrease of Protein Phosphatase 2A Subunit B in Ischemic Brain Injury

PubMed Central

Koh, Phil-Ok

2013-01-01

Background Ferulic acid provides a neuroprotective effect during cerebral ischemia through its anti-oxidant function. Protein phosphatase 2A (PP2A) is a serine and threonine phosphatase that contributes broadly to normal brain function. This study investigated whether ferulic acid regulates PP2A subunit B in a middle cerebral artery occlusion (MCAO) animal model and glutamate toxicity-induced neuronal cell death. Methodology/Principal Findings MCAO was surgically induced to yield permanent cerebral ischemic injury in rats. The rats were treated with either vehicle or ferulic acid (100 mg/kg, i.v.) immediately after MCAO, and cerebral cortex tissues were collected 24 h after MCAO. A proteomics approach, RT-PCR, and Western blot analyses performed to identification of PP2A subunit B expression levels. Ferulic acid significantly reduced the MCAO-induced infarct volume of the cerebral cortex. A proteomics approach elucidated the reduction of PP2A subunit B in MCAO-induced animals, and ferulic acid treatment prevented the injury-induced reduction in PP2A subunit B levels. RT-PCR and Western blot analyses also showed that ferulic acid treatment attenuates the injury-induced decrease in PP2A subunit B levels. Moreover, the number of PP2A subunit B-positive cells was reduced in MCAO-induced animals, and ferulic acid prevented these decreases. In cultured neuronal cells, ferulic acid treatment protected cells against glutamate toxicity and prevented the glutamate-induced decrease in PP2A subunit B. Conclusions/Significance These results suggest that the maintenance of PP2A subunit B by ferulic acid in ischemic brain injury plays an important role for the neuroprotective function of ferulic acid. PMID:23349830

Unusual Variability of the Drosophila Melanogaster Ref(2)p Protein Which Controls the Multiplication of Sigma Rhabdovirus

PubMed Central

Dru, P.; Bras, F.; Dezelee, S.; Gay, P.; Petitjean, A. M.; Pierre-Deneubourg, A.; Teninges, D.; Contamine, D.

1993-01-01

The ref(2)P gene of Drosophila melanogaster was identified by the discovery of two alleles, P(o) and P(p), respectively, permissive and restrictive for sigma rhabdovirus multiplication. A surprising variability of this gene was first noticed by the observation of size differences between the transcripts of permissive and restrictive alleles. In this paper, another restrictive allele, P(n), clearly distinct from P(p), is described: it exhibits a weaker antiviral effect than P(p) and differs from P(p) by its molecular structure. Five types of alleles were distinguished on the basis of their molecular structure, as revealed by S1 nuclease analysis of 17 D. melanogaster strains; three alleles were permissive and two restrictive. Comparison of the sequences of four haplotypes revealed numerous point mutations, two deletions (21 and 24 bp) and a complex event involving a 3-bp deletion, all affected the coding region. The unusual variability of the ref(2)P locus was confirmed by the high ratio of amino acid replacements to synonymous mutations (7:1), as compared to that of other genes, such as the Adh (2:42). Nevertheless, nucleotide sequence comparison with the Drosophila erecta ref(2)P gene shows that selective pressures are exerted to maintain the existence of a functional protein. The effects of this high variability on the ref(2)P protein are discussed in relation to its specific antiviral properties and to its function in D. melanogaster, where it is required for male fertility. PMID:8462852

Protein phosphatase 2A inhibition and subsequent cytoskeleton reorganization contributes to cell migration caused by microcystin-LR in human laryngeal epithelial cells (Hep-2).

PubMed

Wang, Beilei; Liu, Jinghui; Huang, Pu; Xu, Kailun; Wang, Hanying; Wang, Xiaofeng; Guo, Zonglou; Xu, Lihong

2017-03-01

The major toxic mechanism of Microcystin-LR is inhibition of the activity of protein phosphatase 2A (PP2A), resulting in a series of cytotoxic effects. Our previous studies have demonstrated that microcystin-LR (MCLR) induced very different molecular effects in normal cells and the tumor cell line SMMC7721. To further explore the MCLR toxicity mechanism in tumor cells, human laryngeal epithelial cells (Hep-2) was examined in this study. Western blot, immunofluorescence, immunoprecipitation, and transwell migration assay were used to detect the effects of MCLR on PP2A activity, PP2A substrates, cytoskeleton, and cell migration. The results showed that the protein level of PP2A subunits and the posttranslational modification of the catalytic subunit were altered and that the binding of the AC core enzyme as well as the binding of PP2A/C and α4, was also affected. As PP2A substrates, the phosphorylation of MAPK pathway members, p38, ERK1/2, and the cytoskeleton-associated proteins, Hsp27, VASP, Tau, and Ezrin were increased. Furthermore, MCLR induced reorganization of the cytoskeleton and promoted cell migration. Taken together, direct covalent binding to PP2A/C, alteration of the protein levels and posttranslational modification, as well as the binding of subunits, are the main pattern for the effects of MCLR on PP2A in Hep-2. A dose-dependent change in p-Tau and p-Ezrin due to PP2A inhibition may contribute to the changes in the cytoskeleton and be related to the cell migration in Hep-2. Our data provide a comprehensive exposition of the MCLR mechanism on tumor cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 890-903, 2017. © 2016 Wiley Periodicals, Inc.

Decoration of Silica Nanoparticles on Polypropylene Separator for Lithium-Sulfur Batteries.

PubMed

Li, Jing; Huang, Yudai; Zhang, Su; Jia, Wei; Wang, Xingchao; Guo, Yong; Jia, Dianzeng; Wang, Lishi

2017-03-01

A SiO 2 nanoparticle decorated polypropylene (PP) separator (PP-SiO 2 ) has been prepared by simply immersing the PP separator in the hydrolysis solution of tetraethyl orthosilicate (TEOS) with the assistance of Tween-80. After decoration, the thermal stability and the electrolyte wettability of the PP-SiO 2 separator are obviously improved. When the PP-SiO 2 separator is used for lithium-sulfur (Li-S) batteries, the cyclic stability and rate capability of the batteries are greatly enhanced. The capacity retention ratio of the Li-S battery configured with the PP-SiO 2 separator is 64% after 200 cycles at 0.2 C, which is much higher than that configured with the PP separator (45%). Moreover, the rate capacity of the Li-S batteries using the PP-SiO 2 separator reaches 956.3, 691.5, 621, and 567.6 mAh g -1 at the current density of 0.2, 0.5, 1, and 2 C, respectively. The reason could be ascribed to that the polar silica coating not only alleviates the shuttle effect but also facilitates Li-ion migration.

Singlet oxygen feedback delayed fluorescence of protoporphyrin IX in organic solutions.

PubMed

Vinklárek, Ivo S; Scholz, Marek; Dědic, Roman; Hála, Jan

2017-04-12

Delayed fluorescence (DF) of protoporphyrin IX (PpIX) has been recently proposed as a tool for monitoring of mitochondrial oxygen tension in vivo as well as for observation of the effectiveness of photodynamic therapy (PDT) [E. G. Mik, Anesth. Analg., 2013, 117, 834-346; F. Piffaretti et al., J. Biomed. Opt., 2012, 17, 115007]. However, the efficiency of the mechanism of thermal activation (E-type DF), which was considered in the papers, is limited due to a large energy gap between the first excited singlet and the first triplet state of PpIX at room or body temperatures. Moreover, the energy gap is roughly equal to other porphyrinoid photosensitizers that generate DF mostly through the Singlet Oxygen Feedback-Induced mechanism (SOFDF) under certain conditions [M. Scholz and R. Dědic, Singlet Oxygen: Applications in Biosciences and Nanosciences, 2016, vol. 2, pp. 63-81]. The mechanisms of delayed fluorescence of PpIX dissolved either in dimethylformamide (DMF) or in the mixture of DMF with ethylene glycol (EG) were investigated at atmospheric partial pressure of oxygen by means of a simultaneous time-resolved detection of 1 O 2 phosphorescence and PpIX DF which makes a direct comparison of the kinetics and lifetimes of both the luminescence channels possible. Samples of PpIX (100 μM) exhibit concave DF kinetics, which is a typical footprint of the SOFDF mechanism. The dramatic decrease in the DF intensity after adding a selective 1 O 2 quencher sodium azide (NaN 3 , 10 mM) proves that >90% of DF is indeed generated through SOFDF. Moreover, the analysis of the DF kinetics in the presence of NaN 3 implies that the second significant mechanism of DF generation is the triplet-triplet annihilation (P-type DF). The bimolecular mechanism of DF was further confirmed by the decrease of the DF intensity in the more viscous mixture DMF/EG and by the increase of the ratio of DF to the prompt fluorescence (PF) intensity with the increasing excitation intensity. These results show the significant role of the SOFDF mechanism in the DF of PpIX at high concentrations and at atmospheric partial pressure of oxygen and should be considered when developing diagnostic tools for clinical applications.

The Zds proteins control entry into mitosis and target protein phosphatase 2A to the Cdc25 phosphatase.

PubMed

Wicky, Sidonie; Tjandra, Hendri; Schieltz, David; Yates, John; Kellogg, Douglas R

2011-01-01

The Wee1 kinase restrains entry into mitosis by phosphorylating and inhibiting cyclin-dependent kinase 1 (Cdk1). The Cdc25 phosphatase promotes entry into mitosis by removing Cdk1 inhibitory phosphorylation. Experiments in diverse systems have established that Wee1 and Cdc25 are regulated by protein phosphatase 2A (PP2A), but a full understanding of the function and regulation of PP2A in entry into mitosis has remained elusive. In budding yeast, entry into mitosis is controlled by a specific form of PP2A that is associated with the Cdc55 regulatory subunit (PP2A(Cdc55)). We show here that related proteins called Zds1 and Zds2 form a tight stoichiometric complex with PP2A(Cdc55) and target its activity to Cdc25 but not to Wee1. Conditional inactivation of the Zds proteins revealed that their function is required primarily at entry into mitosis. In addition, Zds1 undergoes cell cycle-dependent changes in phosphorylation. Together, these observations define a role for the Zds proteins in controlling specific functions of PP2A(Cdc55) and suggest that upstream signals that regulate PP2A(Cdc55) may play an important role in controlling entry into mitosis.

All roads lead to PP2A: Exploiting the therapeutic potential of this phosphatase

PubMed Central

Sangodkar, Jaya; Farrington, Caroline; McClinch, Kimberly; Galsky, Matthew D.; Kastrinsky, David B.; Narla, Goutham

2015-01-01

Protein phosphatase 2A is a serine/threonine phosphatase involved in the regulation of many cellular processes. A confirmed tumor suppressor protein, PP2A is genetically altered or functionally inactivated in many cancers highlighting a need for its therapeutic reactivation. In this review we will discuss recent literature on PP2A: the elucidation of its structure and the functions of its subunits, and the identification of molecular lesions and post-translational modifications leading to its dysregulation in cancer. A final section will discuss the proteins and small molecules that modulate PP2A and how these might be used to target dysregulated forms of PP2A to treat cancers and other diseases. PMID:26507691

Live-cell imaging RNAi screen identifies PP2A–B55α and importin-β1 as key mitotic exit regulators in human cells

PubMed Central

Schmitz, Michael H. A.; Held, Michael; Janssens, Veerle; Hutchins, James R. A.; Hudecz, Otto; Ivanova, Elitsa; Goris, Jozef; Trinkle-Mulcahy, Laura; Lamond, Angus I.; Poser, Ina; Hyman, Anthony A.; Mechtler, Karl; Peters, Jan-Michael; Gerlich, Daniel W.

2013-01-01

When vertebrate cells exit mitosis various cellular structures are re-organized to build functional interphase cells1. This depends on Cdk1 (cyclin dependent kinase 1) inactivation and subsequent dephosphorylation of its substrates2–4. Members of the protein phosphatase 1 and 2A (PP1 and PP2A) families can dephosphorylate Cdk1 substrates in biochemical extracts during mitotic exit5,6, but how this relates to postmitotic reassembly of interphase structures in intact cells is not known. Here, we use a live-cell imaging assay and RNAi knockdown to screen a genome-wide library of protein phosphatases for mitotic exit functions in human cells. We identify a trimeric PP2A–B55α complex as a key factor in mitotic spindle breakdown and postmitotic reassembly of the nuclear envelope, Golgi apparatus and decondensed chromatin. Using a chemically induced mitotic exit assay, we find that PP2A–B55α functions downstream of Cdk1 inactivation. PP2A–B55α isolated from mitotic cells had reduced phosphatase activity towards the Cdk1 substrate, histone H1, and was hyper-phosphorylated on all subunits. Mitotic PP2A complexes co-purified with the nuclear transport factor importin-β1, and RNAi depletion of importin-β1 delayed mitotic exit synergistically with PP2A–B55α. This demonstrates that PP2A–B55α and importin-β1 cooperate in the regulation of postmitotic assembly mechanisms in human cells. PMID:20711181

Recombinant α- β- and γ-Synucleins Stimulate Protein Phosphatase 2A Catalytic Subunit Activity in Cell Free Assays

PubMed Central

Lek, Sovanarak; Vargas-Medrano, Javier; Villanueva, Ernesto; Marcus, Brian; Godfrey, Wesley; Perez, Ruth G.

2017-01-01

α-Synuclein (aSyn), β-Synuclein (bSyn), and γ-Synuclein (gSyn) are members of a conserved family of chaperone-like proteins that are highly expressed in vertebrate neuronal tissues. Of the three synucleins, only aSyn has been strongly implicated in neurodegenerative disorders such as Parkinson's disease, Dementia with Lewy Bodies, and Multiple System Atrophy. In studying normal aSyn function, data indicate that aSyn stimulates the activity of the catalytic subunit of an abundantly expressed dephosphorylating enzyme, PP2Ac in vitro and in vivo. Prior data show that aSyn aggregation in human brain reduces PP2Ac activity in regions with Lewy body pathology, where soluble aSyn has become insoluble. However, because all three synucleins have considerable homology in the amino acid sequences, experiments were designed to test if all can modulate PP2Ac activity. Using recombinant synucleins and recombinant PP2Ac protein, activity was assessed by malachite green colorimetric assay. Data revealed that all three recombinant synucleins stimulated PP2Ac activity in cell-free assays, raising the possibility that the conserved homology between synucleins may endow all three homologs with the ability to bind to and activate the PP2Ac. Co-immunoprecipitation data, however, suggest that PP2Ac modulation likely occurs through endogenous interactions between aSyn and PP2Ac in vivo. PMID:28829427

Regulation of the tumor marker Fascin by the viral oncoprotein Tax of human T-cell leukemia virus type 1 (HTLV-1) depends on promoter activation and on a promoter-independent mechanism.

PubMed

Mohr, Caroline F; Gross, Christine; Bros, Matthias; Reske-Kunz, Angelika B; Biesinger, Brigitte; Thoma-Kress, Andrea K

2015-11-01

Adult T-cell leukemia/lymphoma is a highly infiltrative neoplasia of CD4(+) T-lymphocytes that occurs in about 5% of carriers infected with the deltaretrovirus human T-cell leukemia virus type 1 (HTLV-1). The viral oncoprotein Tax perturbs cellular signaling pathways leading to upregulation of host cell factors, amongst them the actin-bundling protein Fascin, an invasion marker of several types of cancer. However, transcriptional regulation of Fascin by Tax is poorly understood. In this study, we identified a triple mode of transcriptional induction of Fascin by Tax, which requires (1) NF-κB-dependent promoter activation, (2) a Tax-responsive region in the Fascin promoter, and (3) a promoter-independent mechanism sensitive to the Src family kinase inhibitor PP2. Thus, Tax regulates Fascin by a multitude of signals. Beyond, using Tax-expressing and virus-transformed lymphocytes as a model system, our study is the first to identify the invasion marker Fascin as a novel target of PP2, an inhibitor of metastasis. Copyright © 2015 Elsevier Inc. All rights reserved.

Activation of tumor suppressor protein PP2A inhibits KRAS-driven tumor growth

PubMed Central

Sangodkar, Jaya; Perl, Abbey; Tohme, Rita; Kiselar, Janna; Kastrinsky, David B.; Izadmehr, Sudeh; Mazhar, Sahar; Wiredja, Danica D.; O’Connor, Caitlin M.; Hoon, Divya; Dhawan, Neil S.; Schlatzer, Daniela; Yao, Shen; Leonard, Daniel; Borczuk, Alain C.; Gokulrangan, Giridharan; Wang, Lifu; Svenson, Elena; Farrington, Caroline C.; Yuan, Eric; Avelar, Rita A.; Stachnik, Agnes; Smith, Blake; Gidwani, Vickram; Giannini, Heather M.; McQuaid, Daniel; McClinch, Kimberly; Wang, Zhizhi; Levine, Alice C.; Sears, Rosalie C.; Chen, Edward Y.; Duan, Qiaonan; Datt, Manish; Ma’ayan, Avi; DiFeo, Analisa; Sharma, Neelesh; Galsky, Matthew D.; Brautigan, David L.; Ioannou, Yiannis A.; Xu, Wenqing; Chance, Mark R.; Ohlmeyer, Michael

2017-01-01

Targeted cancer therapies, which act on specific cancer-associated molecular targets, are predominantly inhibitors of oncogenic kinases. While these drugs have achieved some clinical success, the inactivation of kinase signaling via stimulation of endogenous phosphatases has received minimal attention as an alternative targeted approach. Here, we have demonstrated that activation of the tumor suppressor protein phosphatase 2A (PP2A), a negative regulator of multiple oncogenic signaling proteins, is a promising therapeutic approach for the treatment of cancers. Our group previously developed a series of orally bioavailable small molecule activators of PP2A, termed SMAPs. We now report that SMAP treatment inhibited the growth of KRAS-mutant lung cancers in mouse xenografts and transgenic models. Mechanistically, we found that SMAPs act by binding to the PP2A Aα scaffold subunit to drive conformational changes in PP2A. These results show that PP2A can be activated in cancer cells to inhibit proliferation. Our strategy of reactivating endogenous PP2A may be applicable to the treatment of other diseases and represents an advancement toward the development of small molecule activators of tumor suppressor proteins. PMID:28504649

Genomic characterization of bacteriophage vB_PcaP_PP2 infecting Pectobacterium carotovorum subsp. carotovorum, a new member of a proposed genus in the subfamily Autographivirinae.

PubMed

Lim, Jeong-A; Heu, Sunggi; Park, Jinwoo; Roh, Eunjung

2017-08-01

Bacteriophage vB_PcaP_PP2 (PP2) is a novel virulent phage that infects the plant-pathogenic bacterium Pectobacterium carotovorum subsp. carotovorum. PP2 phage has a 41,841-bp double-stranded DNA encoding 47 proteins, and it was identified as a member of the family Podoviridae by transmission electron microscopy. Nineteen of its open reading frames (ORFs) show homology to functional proteins, and 28 ORFs have been characterized as hypothetical proteins. PP2 phage is homologous to Cronobacter phage vB_CskP_GAP227 and Dev-CD-23823. Based on phylogenetic analysis, PP2 and its homologous bacteriophages form a new group within the subfamily Autographivirinae in the family Podoviridae, suggesting the need to establish a new genus. No lysogenic-cycle-related genes or bacterial toxins were identified.

A Rare Terminal Dinitrogen Complex of Chromium

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

Mock, Michael T.; Chen, Shentan; Rousseau, Roger J.

The reduction of dinitrogen to ammonia from N2 and H2 is currently carried out by the Haber-Bosch process, an energy intensive process that requires high pressures and high temperatures and accounts for the production of millions of tons of ammonia per year. The development of a catalytic, energy-efficient process for N2 reduction is of great interest and remains a formidable challenge. In this communication, we are reporting the preparation, characterization and computational electronic structure analysis of a rare 'Chatt-type' ((P-P)2M(N2)2, P-P = diphosphine ligand) complex of chromium, cis-[Cr(N2)2(PPh2NBn2)2] and its reactivity with CO. This complex is supported by the diphosphinemore » ligand PPh2NBn2, containing non-coordinating pendant amine bases, to serve as proton relays. Future studies for this complex are aimed at answering fundamental questions regarding the role of proton relays in the second coordination sphere in their ability to facilitate proton movement from an external acid to metal-bound dinitrogen ligands in the challenging multi-proton/electron reduction of N2 to ammonia.« less

Arctigenin inhibits triple-negative breast cancers by targeting CIP2A to reactivate protein phosphatase 2A.

PubMed

Huang, Qiuyue; Qin, Shanshan; Yuan, Xiaoning; Zhang, Liang; Ji, Juanli; Liu, Xuewen; Ma, Wenjing; Zhang, Yunfei; Liu, Pengfei; Sun, Zhiting; Zhang, Jingxuan; Liu, Ying

2017-07-01

We have shown that a novel STAT3 inhibitor arctigenin (Atn) induces significant cytotoxicity in triple-negative breast cancer (TNBC) cells. This study further delineated molecular mechanisms where by Atn triggered cytotoxicity in TNBC cells. We found Atn can also inhibit metastasis in TNBC cells through cancerous inhibitor of protein phosphatase 2A (CIP2A) pathway. CIP2A is an endogenous inhibitor of protein phosphatase 2A (PP2A), which can increase the migration and invasion of various cancer cells. PP2A is a tumor suppressor, which is functionally defective in various cancers. Atn-induced metastasis inhibition was associated with reactivation of PP2A, downregulation of CIP2A and Akt phosphorylation. Silencing CIP2A enhanced Atn-induced metastasis inhibition and apoptosis in TNBCs. Furthermore, ectopic expression of CIP2A or inhibition of PP2A in TNBC cells abolished the effects of Atn. In conclusion, we found that enhancement of PP2A activity by inhibition of CIP2A, at least in part, promotes the anti-metastasis effect induced by Atn. Our findings disclose the novel therapeutic mechanism of this targeted agent, and suggest the therapeutic potential and feasibility of developing PP2A enhancers as a novel anticancer strategy.

The Zds proteins control entry into mitosis and target protein phosphatase 2A to the Cdc25 phosphatase

PubMed Central

Wicky, Sidonie; Tjandra, Hendri; Schieltz, David; Yates, John; Kellogg, Douglas R.

2011-01-01

The Wee1 kinase restrains entry into mitosis by phosphorylating and inhibiting cyclin-dependent kinase 1 (Cdk1). The Cdc25 phosphatase promotes entry into mitosis by removing Cdk1 inhibitory phosphorylation. Experiments in diverse systems have established that Wee1 and Cdc25 are regulated by protein phosphatase 2A (PP2A), but a full understanding of the function and regulation of PP2A in entry into mitosis has remained elusive. In budding yeast, entry into mitosis is controlled by a specific form of PP2A that is associated with the Cdc55 regulatory subunit (PP2ACdc55). We show here that related proteins called Zds1 and Zds2 form a tight stoichiometric complex with PP2ACdc55 and target its activity to Cdc25 but not to Wee1. Conditional inactivation of the Zds proteins revealed that their function is required primarily at entry into mitosis. In addition, Zds1 undergoes cell cycle–dependent changes in phosphorylation. Together, these observations define a role for the Zds proteins in controlling specific functions of PP2ACdc55 and suggest that upstream signals that regulate PP2ACdc55 may play an important role in controlling entry into mitosis. PMID:21119008

Contrasting responses to drought of forest floor CO2 efflux in a loblolly pine plantation and a nearby Oak-Hickory forest

Treesearch

S. Palmroth; Chris A. Maier; Heather R. McCarthy; A. C. Oishi; H. S. Kim; Kurt H. Johnsen; Gabrial G. Katul; Ram Oren

2005-01-01

Forest floor C02 efflux (Fff) depends on vegetation type, climate, and soil physical properties. We assessed the effects of biological factors on Fff by comparing a maturing pine plantation (PP) and a nearby mature Oak-Hickory-type hardwood forest (HW). Fff was measured...

Methylation-regulated decommissioning of multimeric PP2A complexes

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

Wu, Cheng-Guo; Zheng, Aiping; Jiang, Li

2017-12-01

Dynamic assembly/disassembly of signaling complexes are crucial for cellular functions. Specialized latency and activation chaperones control the biogenesis of protein phosphatase 2A (PP2A) holoenzymes that contain a common scaffold and catalytic subunits and a variable regulatory subunit. Here we show that the butterfly-shaped TIPRL (TOR signaling pathway regulator) makes highly integrative multibranching contacts with the PP2A catalytic subunit, selective for the unmethylated tail and perturbing/inactivating the phosphatase active site. TIPRL also makes unusual wobble contacts with the scaffold subunit, allowing TIPRL, but not the overlapping regulatory subunits, to tolerate disease-associated PP2A mutations, resulting in reduced holoenzyme assembly and enhanced inactivationmore » of mutant PP2A. Strikingly, TIPRL and the latency chaperone, α4, coordinate to disassemble active holoenzymes into latent PP2A, strictly controlled by methylation. Our study reveals a mechanism for methylation-responsive inactivation and holoenzyme disassembly, illustrating the complexity of regulation/signaling, dynamic complex disassembly, and disease mutations in cancer and intellectual disability.« less

ACE Gene I/D Polymorphism and Obesity in 1,574 Patients with Type 2 Diabetes Mellitus.

PubMed

Pan, Yan-Hong; Wang, Min; Huang, Yan-Mei; Wang, Ying-Hui; Chen, Yin-Ling; Geng, Li-Jun; Zhang, Xiao-Xi; Zhao, Hai-Lu

2016-01-01

Association between ACE gene I/D polymorphism and the risk of overweight/obesity remains controversial. We investigated the possible relationship between ACE gene I/D polymorphism and obesity in Chinese type 2 diabetes mellitus (T2DM) patients. In this study, obesity was defined as a body mass index (BMI) value ≥ 25 kg/m 2 and subjects were classified into 4 groups (lean, normal, overweight, and obese). PCR (polymerase chain reaction) was used to detect the ACE gene I/D polymorphism in T2DM patients. Metabolic measurements including blood glucose, lipid profile, and blood pressure were obtained. Frequencies of the ACE genotypes (DD, ID, and II) were not significant among the 4 groups of BMI-defined patients ( P = 0.679) while ACE II carriers showed higher systolic blood pressure (SBP) and pulse pressure (PP) (all P < 0.050). Hyperglycemia, hypertension, and dyslipidemia in these T2DM patients were found to be significantly associated with BMI. In conclusion, the relationship of ACE gene I/D polymorphism with obesity is insignificant in Chinese patients with T2DM. SBP and PP might be higher in the ACE II carriers than in the DD and ID carriers.

The homeodomain-leucine zipper (HD-Zip) class I transcription factors ATHB7 and ATHB12 modulate abscisic acid signalling by regulating protein phosphatase 2C and abscisic acid receptor gene activities.

PubMed

Valdés, Ana Elisa; Overnäs, Elin; Johansson, Henrik; Rada-Iglesias, Alvaro; Engström, Peter

2012-11-01

Plants perceiving drought activate multiple responses to improve survival, including large-scale alterations in gene expression. This article reports on the roles in the drought response of two Arabidopsis thaliana homeodomain-leucine zipper class I genes; ATHB7 and ATHB12, both strongly induced by water-deficit and abscisic acid (ABA). ABA-mediated transcriptional regulation of both genes is shown to depend on the activity of protein phosphatases type 2C (PP2C). ATHB7 and ATHB12 are, thus, targets of the ABA signalling mechanism defined by the PP2Cs and the PYR/PYL family of ABA receptors, with which the PP2C proteins interact. Our results from chromatin immunoprecipitation and gene expression analyses demonstrate that ATHB7 and ATHB12 act as positive transcriptional regulators of PP2C genes, and thereby as negative regulators of abscisic acid signalling. In support of this notion, our results also show that ATHB7 and ATHB12 act to repress the transcription of genes encoding the ABA receptors PYL5 and PYL8 in response to an ABA stimulus. In summary, we demonstrate that ATHB7 and ATHB12 have essential functions in the primary response to drought, as mediators of a negative feedback effect on ABA signalling in the plant response to water deficit.

Protein Kinase C Controls Binding of Igo/ENSA Proteins to Protein Phosphatase 2A in Budding Yeast.

PubMed

Thai, Vu; Dephoure, Noah; Weiss, Amit; Ferguson, Jacqueline; Leitao, Ricardo; Gygi, Steven P; Kellogg, Douglas R

2017-03-24

Protein phosphatase 2A (PP2A) plays important roles in controlling mitosis in all eukaryotic cells. The form of PP2A that controls mitosis is associated with a conserved regulatory subunit that is called B55 in vertebrates and Cdc55 in budding yeast. The activity of this form of PP2A can be inhibited by binding of conserved Igo/ENSA proteins. Although the mechanisms that activate Igo/ENSA to bind and inhibit PP2A are well understood, little is known about how Igo/Ensa are inactivated. Here, we have analyzed regulation of Igo/ENSA in the context of a checkpoint pathway that links mitotic entry to membrane growth in budding yeast. Protein kinase C (Pkc1) relays signals in the pathway by activating PP2A Cdc55 We discovered that constitutively active Pkc1 can drive cells through a mitotic checkpoint arrest, which suggests that Pkc1-dependent activation of PP2A Cdc55 plays a critical role in checkpoint signaling. We therefore used mass spectrometry to determine how Pkc1 modifies the PP2A Cdc55 complex. This revealed that Pkc1 induces changes in the phosphorylation of multiple subunits of the complex, as well as dissociation of Igo/ENSA. Pkc1 directly phosphorylates Cdc55 and Igo/ENSA, and phosphorylation site mapping and mutagenesis indicate that phosphorylation of Cdc55 contributes to Igo/ENSA dissociation. Association of Igo2 with PP2A Cdc55 is regulated during the cell cycle, yet mutation of Pkc1-dependent phosphorylation sites on Cdc55 and Igo2 did not cause defects in mitotic progression. Together, the data suggest that Pkc1 controls PP2A Cdc55 by multiple overlapping mechanisms. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Evaluation of the effect of organic pro-degradant concentration in polypropylene exposed to the natural ageing

NASA Astrophysics Data System (ADS)

Montagna, L. S.; Catto, A. L.; Rossini, K.; Forte, M. M. C.; Santana, R. M. C.

2014-05-01

The production and consumption of plastics in the last decade has recorded a remarkable increase in the scientific and industrial interest in environmentally degradable polymer (EDPs). Polymers wastes are deposited improperly, such as dumps, landfills, rivers and seas, causing a serious problem by the accumulation in the environment. The abiotic processes, like the photodegradation, are the most efficient occurring in the open environmental, where the polymers undergo degradation from the action of sunlight that result from direct exposure to solar radiation, however depend of the type of chemical ageing, which is the principal component of climatic ageing. The subject of this work is to study the influence of concentration of organic pro-degradant (1, 2 and 3 % w/w) in the polypropylene (PP) exposed in natural ageing. PP samples with and without the additive were processed in plates square form, obtained by thermal compression molding (TCM) using a press at 200°C under 2 tons for 5 min, and then were exposed at natural ageing during 120 days. The presence of organic additive influenced on PP degradability, this fact was assessed by changes in the thermal and morphology properties of the samples after 120 days of natural ageing. Scanning Electronic Microscopy (SEM) results of the morphological surface of the modified PP samples showed greater degradation photochemical oxidative when compared to neat PP, due to increase of rugosity and formation of microvoids. PP samples with different pro-degradant concentration under natural ageing presented a degree of crystallinity, obtained by Differential Scanning Calorimeter (DSC) increases in comparing the neat PP.

Structural basis for basal activity and autoactivation of abscisic acid (ABA) signaling SnRK2 kinases

PubMed Central

Ng, Ley-Moy; Soon, Fen-Fen; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Suino-Powell, Kelly M.; Chalmers, Michael J.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric

2011-01-01

Abscisic acid (ABA) is an essential hormone that controls plant growth, development, and responses to abiotic stresses. Central for ABA signaling is the ABA-mediated autoactivation of three monomeric Snf1-related kinases (SnRK2.2, -2.3, and -2.6). In the absence of ABA, SnRK2s are kept in an inactive state by forming physical complexes with type 2C protein phosphatases (PP2Cs). Upon relief of this inhibition, SnRK2 kinases can autoactivate through unknown mechanisms. Here, we report the crystal structures of full-length Arabidopsis thaliana SnRK2.3 and SnRK2.6 at 1.9- and 2.3-Å resolution, respectively. The structures, in combination with biochemical studies, reveal a two-step mechanism of intramolecular kinase activation that resembles the intermolecular activation of cyclin-dependent kinases. First, release of inhibition by PP2C allows the SnRK2s to become partially active because of an intramolecular stabilization of the catalytic domain by a conserved helix in the kinase regulatory domain. This stabilization enables SnRK2s to gain full activity by activation loop autophosphorylation. Autophosphorylation is more efficient in SnRK2.6, which has higher stability than SnRK2.3 and has well-structured activation loop phosphate acceptor sites that are positioned next to the catalytic site. Together, these data provide a structural framework that links ABA-mediated release of PP2C inhibition to activation of SnRK2 kinases. PMID:22160701

Evolution of Abscisic Acid Synthesis and Signaling Mechanisms

PubMed Central

Hauser, Felix; Waadt, Rainer; Schroeder, Julian I.

2011-01-01

The plant hormone abscisic acid (ABA) mediates seed dormancy, controls seedling development and triggers tolerance to abiotic stresses, including drought. Core ABA signaling components consist of a recently identified group of ABA receptor proteins of the PYRABACTIN RESISTANCE (PYR)/REGULATORY COMPONENT OF ABA RECEPTOR (RCAR) family that act as negative regulators of members of the PROTEIN PHOSPHATASE 2C (PP2C) family. Inhibition of PP2C activity enables activation of SNF1-RELATED KINASE 2 (SnRK2) protein kinases, which target downstream components, including transcription factors, ion channels and NADPH oxidases. These and other components form a complex ABA signaling network. Here, an in depth analysis of the evolution of components in this ABA signaling network shows that (i) PYR/RCAR ABA receptor and ABF-type transcription factor families arose during land colonization of plants and are not found in algae and other species, (ii) ABA biosynthesis enzymes have evolved to plant- and fungal-specific forms, leading to different ABA synthesis pathways, (iii) existing stress signaling components, including PP2C phosphatases and SnRK kinases, were adapted for novel roles in this plant-specific network to respond to water limitation. In addition, evolutionarily conserved secondary structures in the PYR/RCAR ABA receptor family are visualized. PMID:21549957

Synthesis of Phenanthro[1,10,9,8-cdefg]carbazole-Based Conjugated Polymers for Green-Selective Organic Photodiodes.

PubMed

Sung, Min Jae; Yoon, Seongwon; Kwon, Soon-Ki; Kim, Yun-Hi; Chung, Dae Sung

2016-11-16

A push-pull-type donor copolymer, named PP-TPD, was synthesized with the Suzuki coupling reaction using 6H-phenanthro[1,10,9,8-cdefg]carbazole (PCZ) as the donor unit and 1,3-bis(5-bromothiophen-2-yl)-5-octyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (TPD) as the acceptor unit. The synthesized PP-TPD was systematically investigated in terms of crystallinity and thermal, electrical, electrochemical, and optical properties. PP-TPD revealed green-selective absorption with a narrow full width at half-maximum of 138 nm. Green-selective organic photodiodes (OPDs) were constructed using PP-TPD as the green-absorbing donor and ZnO as the nonabsorbing acceptor material. The fabricated OPDs exhibited an extremely low dark current of 0.68 nA/cm 2 at -5 V and a high detectivity above 10 12 Jones at 550 nm. Moreover, they showed a sufficiently high 3-dB frequency and a linear dynamic range, similar to those of ideal-operating OPDs. The origin and physics background of the observed low dark current and high detectivity are discussed in detail.

Gravitropism of Arabidopsis thaliana Roots Requires the Polarization of PIN2 toward the Root Tip in Meristematic Cortical Cells[C][W

PubMed Central

Rahman, Abidur; Takahashi, Maho; Shibasaki, Kyohei; Wu, Shuang; Inaba, Takehito; Tsurumi, Seiji; Baskin, Tobias I.

2010-01-01

In the root, the transport of auxin from the tip to the elongation zone, referred to here as shootward, governs gravitropic bending. Shootward polar auxin transport, and hence gravitropism, depends on the polar deployment of the PIN-FORMED auxin efflux carrier PIN2. In Arabidopsis thaliana, PIN2 has the expected shootward localization in epidermis and lateral root cap; however, this carrier is localized toward the root tip (rootward) in cortical cells of the meristem, a deployment whose function is enigmatic. We use pharmacological and genetic tools to cause a shootward relocation of PIN2 in meristematic cortical cells without detectably altering PIN2 polarization in other cell types or PIN1 polarization. This relocation of cortical PIN2 was negatively regulated by the membrane trafficking factor GNOM and by the regulatory A1 subunit of type 2-A protein phosphatase (PP2AA1) but did not require the PINOID protein kinase. When GNOM was inhibited, PINOID abundance increased and PP2AA1 was partially immobilized, indicating both proteins are subject to GNOM-dependent regulation. Shootward PIN2 specifically in the cortex was accompanied by enhanced shootward polar auxin transport and by diminished gravitropism. These results demonstrate that auxin flow in the root cortex is important for optimal gravitropic response. PMID:20562236

Deodorisation effect of diamond-like carbon/titanium dioxide multilayer thin films deposited onto polypropylene

NASA Astrophysics Data System (ADS)

Ozeki, K.; Hirakuri, K. K.; Masuzawa, T.

2011-04-01

Many types of plastic containers have been used for the storage of food. In the present study, diamond-like carbon (DLC)/titanium oxide (TiO2) multilayer thin films were deposited on polypropylene (PP) to prevent flavour retention and to remove flavour in plastic containers. For the flavour removal test, two types of multilayer films were prepared, DLC/TiO2 films and DLC/TiO2/DLC films. The residual gas concentration of acetaldehyde, ethylene, and turmeric compounds in bottle including the DLC/TiO2-coated and the DLC/TiO2/DLC-coated PP plates were measured after UV radiation, and the amount of adsorbed compounds to the plates was determined. The percentages of residual gas for acetaldehyde, ethylene, and turmeric with the DLC/TiO2 coated plates were 0.8%, 65.2% and 75.0% after 40 h of UV radiation, respectively. For the DLC/TiO2/DLC film, the percentages of residual gas for acetaldehyde, ethylene and turmeric decreased to 34.9%, 76.0% and 85.3% after 40 h of UV radiation, respectively. The DLC/TiO2/DLC film had a photocatalytic effect even though the TiO2 film was covered with the DLC film.

Biosynthesis of allene oxides in Physcomitrella patens

PubMed Central

2012-01-01

Background The moss Physcomitrella patens contains C18- as well as C20-polyunsaturated fatty acids that can be metabolized by different enzymes to form oxylipins such as the cyclopentenone cis(+)-12-oxo phytodienoic acid. Mutants defective in the biosynthesis of cyclopentenones showed reduced fertility, aberrant sporophyte morphology and interrupted sporogenesis. The initial step in this biosynthetic route is the conversion of a fatty acid hydroperoxide to an allene oxide. This reaction is catalyzed by allene oxide synthase (AOS) belonging as hydroperoxide lyase (HPL) to the cytochrome P450 family Cyp74. In this study we characterized two AOS from P. patens, PpAOS1 and PpAOS2. Results Our results show that PpAOS1 is highly active with both C18 and C20-hydroperoxy-fatty acid substrates, whereas PpAOS2 is fully active only with C20-substrates, exhibiting trace activity (~1000-fold lower kcat/KM) with C18 substrates. Analysis of products of PpAOS1 and PpHPL further demonstrated that both enzymes have an inherent side activity mirroring the close inter-connection of AOS and HPL catalysis. By employing site directed mutagenesis we provide evidence that single amino acid residues in the active site are also determining the catalytic activity of a 9-/13-AOS – a finding that previously has only been reported for substrate specific 13-AOS. However, PpHPL cannot be converted into an AOS by exchanging the same determinant. Localization studies using YFP-labeled AOS showed that PpAOS2 is localized in the plastid while PpAOS1 may be found in the cytosol. Analysis of the wound-induced cis(+)-12-oxo phytodienoic acid accumulation in PpAOS1 and PpAOS2 single knock-out mutants showed that disruption of PpAOS1, in contrast to PpAOS2, results in a significantly decreased cis(+)-12-oxo phytodienoic acid formation. However, the knock-out mutants of neither PpAOS1 nor PpAOS2 showed reduced fertility, aberrant sporophyte morphology or interrupted sporogenesis. Conclusions Our study highlights five findings regarding the oxylipin metabolism in P. patens: (i) Both AOS isoforms are capable of metabolizing C18- and C20-derived substrates with different specificities suggesting that both enzymes might have different functions. (ii) Site directed mutagenesis demonstrated that the catalytic trajectories of 9-/13-PpAOS1 and PpHPL are closely inter-connected and PpAOS1 can be inter-converted by a single amino acid exchange into a HPL. (iii) In contrast to PpAOS1, PpAOS2 is localized in the plastid where oxylipin metabolism takes place. (iv) PpAOS1 is essential for wound-induced accumulation of cis(+)-12-oxo phytodienoic acid while PpAOS2 appears not to be involved in the process. (v) Knock-out mutants of neither AOS showed a deviating morphological phenotype suggesting that there are overlapping functions with other Cyp74 enzymes. PMID:23194461

Phosphorus loads from different urban storm runoff sources in southern China: a case study in Wenzhou City.

PubMed

Zhou, Dong; Bi, Chun-Juan; Chen, Zhen-Lou; Yu, Zhong-Jie; Wang, Jun; Han, Jing-Chao

2013-11-01

Storm runoff from six types of underlying surface area during five rainfall events in two urban study areas of Wenzhou City, China was investigated to measure phosphorus (P) concentrations and discharge rates. The average event mean concentrations (EMCs) of total phosphorus (TP), total dissolved phosphorus (TDP), and particulate phosphorus (PP) ranged from 0.02 to 2.5 mg · L(-1), 0.01 to 0.48 mg · L(-1), and 0.02 to 2.43 mg · L(-1), respectively. PP was generally the dominant component of TP in storm runoff, while the major form of P varied over time, especially in roof runoff, where TDP made up the largest portion in the latter stages of runoff events. Both TP and PP concentrations were positively correlated with pH, total suspended solids (TSS), and biochemical oxygen demand (BOD)/chemical oxygen demand (COD) concentrations (p<0.01), while TDP was positively correlated with BOD/COD only (p<0.01). In addition, the EMCs of TP and PP were negatively correlated with maximum rainfall intensity (p<0.05), while the EMCs of TDP positively correlated with the antecedent dry weather period (p<0.05). The annual TP emission fluxes from the two study areas were 367.33 and 237.85 kg, respectively. Underlying surface type determined the TP and PP loadings in storm runoff, but regional environmental conditions affected the export of TDP more significantly. Our results indicate that the removal of particles from storm runoff could be an effective measure to attenuate P loadings to receiving water bodies.

The interaction between AMPKβ2 and the PP1-targeting subunit R6 is dynamically regulated by intracellular glycogen content.

PubMed

Oligschlaeger, Yvonne; Miglianico, Marie; Dahlmans, Vivian; Rubio-Villena, Carla; Chanda, Dipanjan; Garcia-Gimeno, Maria Adelaida; Coumans, Will A; Liu, Yilin; Voncken, J Willem; Luiken, Joost J F P; Glatz, Jan F C; Sanz, Pascual; Neumann, Dietbert

2016-04-01

AMP-activated protein kinase (AMPK) is a metabolic stress-sensing kinase. We previously showed that glucose deprivation induces autophosphorylation of AMPKβ at Thr-148, which prevents the binding of AMPK to glycogen. Furthermore, in MIN6 cells, AMPKβ1 binds to R6 (PPP1R3D), a glycogen-targeting subunit of protein phosphatase type 1 (PP1), thereby regulating the glucose-induced inactivation of AMPK. In the present study, we further investigated the interaction of R6 with AMPKβ and the possible dependency on Thr-148 phosphorylation status. Yeast two-hybrid (Y2H) analyses and co-immunoprecipitation (IP) of the overexpressed proteins in human embryonic kidney (HEK) 293T) cells revealed that both AMPKβ1 and AMPK-β2 wild-type (WT) isoforms bind to R6. The AMPKβ-R6 interaction was stronger with the muscle-specific AMPKβ2-WT and required association with the substrate-binding motif of R6. When HEK293T cells or C2C12 myotubes were cultured in high-glucose medium, AMPKβ2-WT and R6 weakly interacted. In contrast, glycogen depletion significantly enhanced this protein interaction. Mutation of AMPKβ2 Thr-148 prevented the interaction with R6 irrespective of the intracellular glycogen content. Treatment with the AMPK activator oligomycin enhanced the AMPKβ2-R6 interaction in conjunction with increased Thr-148 phosphorylation in cells grown in low-glucose medium. These data are in accordance with R6 binding directly to AMPKβ2 when both proteins detach from the diminishing glycogen particle, which is simultaneous with increased AMPKβ2 Thr-148 autophosphorylation. Such a model points to a possible control of AMPK by PP1-R6 upon glycogen depletion in muscle. © 2016 Authors; published by Portland Press Limited.

Proceedings of the Antenna Applications Symposium Held on 23-25 September 1992. Volume 2

DTIC Science & Technology

1993-06-01

Kahrizi, S. M. Rao, and A . R. Djordjevic, "Analysis of arbitrarily shaped microstrip patch anten- nas using the Sommerfeld formulation," Int. J...Trans. Antennas Propagat., vol. AP-34, pp. 905-911, July 1986. [231 W. C. Chew, Z. Nie, and Y. T. Lo, "The effect of feed on the input impedance of a ...microstrip antenna," Microwave & Opt. Technol. Lett., vol. 3, pp. 79-83, Mar. 1990. [24] W. C. Chew, " A quick way to approximate a Sommerfeld -Weyl-type

Cloning and functional analysis of 9-cis-epoxycarotenoid dioxygenase (NCED) genes encoding a key enzyme during abscisic acid biosynthesis from peach and grape fruits.

PubMed

Zhang, Mei; Leng, Ping; Zhang, Guanglian; Li, Xiangxin

2009-08-15

Ripening and senescence are generally controlled by ethylene in climacteric fruits like peaches, and the ripening process of grape, a non-climacteric fruit, may have some relationship to abscisic acid (ABA) function. In order to better understand the role of ABA in ripening and senescence of these two types of fruits, we cloned the 9-cis-epoxycarotenoid dioxygenase (NCED) gene that encodes a key enzyme in ABA biosynthesis from peaches and grapes using an RT-PCR approach. The NCED gene fragments were cloned from peaches (PpNCED1and PpNCED2, each 740bp) and grapes (VVNCED1, 741bp) using degenerate primers designed based on the conserved amino acids sequence of NCEDs in other plants. PpNCED1 showed 78.54% homology with PpNCED2, 74.90% homology with VVNCED1, and both showed high homology to NCEDs from other plants. The expression patterns of PpNCED1 and VVNCED1 were very similar. Both were highly expressed at the beginning of ripening when ABA content becomes high. The maximum ABA preceded ethylene production in peach fruit. ABA in the grape gradually increased from the beginning of ripening and reached the highest level at 20d before the harvest stage. However, ethylene remained at low levels during the entire process of fruit development, including ripening and senescence. ABA content, and ripening and softening of both types of fruits, were promoted or delayed by exogenous ABA or Fluridone (or NDGA) treatment. The roles of ABA and ethylene in the later ripening of fruit are complex. Based on results obtained in this study, we concluded that PpNCED1 and VVNCED1 initiate ABA biosynthesis at the beginning of fruit ripening, and that ABA accumulation might play a key role in the regulation of ripeness and senescence of both peach and grape fruits.

Gene regulation mediating fiber-type transformation in skeletal muscle cells is partly glucose- and ChREBP-dependent.

PubMed

Hanke, Nina; Scheibe, Renate J; Manukjan, Georgi; Ewers, David; Umeda, Patrick K; Chang, Kin-Chow; Kubis, Hans-Peter; Gros, Gerolf; Meissner, Joachim D

2011-03-01

Adaptations in the oxidative capacity of skeletal muscle cells can occur under several physiological or pathological conditions. We investigated the effect of increasing extracellular glucose concentration on the expression of markers of energy metabolism in primary skeletal muscle cells and the C2C12 muscle cell line. Growth of myotubes in 25mM glucose (high glucose, HG) compared with 5.55mM led to increases in the expression and activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a marker of glycolytic energy metabolism, while oxidative markers peroxisome proliferator-activated receptor γ coactivator 1α and citrate synthase decreased. HG induced metabolic adaptations as are seen during a slow-to-fast fiber transformation. Furthermore, HG increased fast myosin heavy chain (MHC) IId/x but did not change slow MHCI/β expression. Protein phosphatase 2A (PP2A) was shown to mediate the effects of HG on GAPDH and MHCIId/x. Carbohydrate response element-binding protein (ChREBP), a glucose-dependent transcription factor downstream of PP2A, partially mediated the effects of glucose on metabolic markers. The glucose-induced increase in PP2A activity was associated with an increase in p38 mitogen-activated protein kinase activity, which presumably mediates the increase in MHCIId/x promoter activity. Liver X receptor, another possible mediator of glucose effects, induced only an incomplete metabolic shift, mainly increasing the expression of the glycolytic marker. Taken together, HG induces a partial slow-to-fast transformation comprising metabolic enzymes together with an increased expression of MHCIId/x. This work demonstrates a functional role for ChREBP in determining the metabolic type of muscle fibers and highlights the importance of glucose as a signaling molecule in muscle. Copyright © 2011 Elsevier B.V. All rights reserved.

Small subunit of a cold-resistant plant, Timothy, does not significantly alter the catalytic properties of Rubisco in transgenic rice.

PubMed

Fukayama, Hiroshi; Koga, Atsushi; Hatanaka, Tomoko; Misoo, Shuji

2015-04-01

Effects of overexpression of high activity-type Rubisco small subunit (RbcS) from a cold-resistant plant, timothy (Phleum pratense), on kinetic properties of Rubisco were studied in rice (Oryza sativa). The full-length mRNA sequence of timothy RbcS (PpRbcS1) was determined by 5'RACE and 3'RACE. The coding sequence of PpRbcS1 was fused to the chlorophyll a/b-binding protein promoter and introduced into rice. PpRbcS was highly expressed in leaf blade and accounted for approximately 30 % of total RbcS in homozygous transgenic lines. However, the catalytic turnover rate and K m for CO2 of Rubisco did not significantly change in these transgenic lines compared to non-transgenic rice, suggesting that PpRbcS1 is not effective for improvement of catalytic efficiency of rice Rubisco. The photosynthetic rate and growth were essentially unchanged, whereas the photosynthetic rate at low CO2 condition was marginally increased in transgenic lines. Rubisco content was significantly increased, whereas soluble protein, nitrogen, and chlorophyll contents were unchanged in transgenic lines compared to non-transgenic rice. Because the kinetic properties were similar, observed slight increase in photosynthetic rate at low CO2 is considered to be large due to increase in Rubisco content in transgenic lines. Introduction of foreign RbcS is an effective approach for the improvement of Rubisco kinetics and photosynthesis. However, in this study, it was suggested that RbcS of high activity-type Rubisco, even showing higher amino acid identity with rice RbcS, did not always enhance the catalytic turnover rate of Rubisco in rice. Thus, we should carefully select RbcS to be overexpressed before introduction.

Barrier properties of PE, PP and EVA (nano)composites - The influence of filler type and concentration

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

Merinska, D.; Kalendova, A.; Tesarikova, A.

2014-05-15

Nanocomposite materials with layered clay used as nanofiller and polyethylene (PE), polypropylene (PP) and copolymer ethylene and vinyl acetate matrix (EVA, the content of VA component 19 wt. %) were prepared by compounding the individual components in Brabender kneader. The MMT Na+ and four types of commercial products such as Nanofil N 5 and N3000, Cloisite 93A and 30B were used as nanofillers. Next to the clays microprecipitated CaHCO{sub 3}, nanosilica and Halloysite tubes were used. The quantity of all the above-mentioned (nano)fillers was 1, 3 and 5 wt. % in relation to the content of montmorillonite. The aim wasmore » to evaluate the influence of (nano)filler type and concentration on nanocomposite barrier properties. The morphology of nanocomposite samples was examined by means of XRD analysis illustrated by transmission electronic microscopy TEM. Furthermore, permeability for O{sub 2} and CO{sub 2} were observed.« less

Structure-Activity Relationship Studies Using Natural and Synthetic Okadaic Acid/Dinophysistoxin Toxins.

PubMed

Twiner, Michael J; Doucette, Gregory J; Pang, Yucheng; Fang, Chao; Forsyth, Craig J; Miles, Christopher O

2016-11-04

Okadaic acid (OA) and the closely related dinophysistoxins (DTXs) are algal toxins that accumulate in shellfish and are known serine/threonine protein phosphatase (ser/thr PP) inhibitors. Phosphatases are important modulators of enzyme activity and cell signaling pathways. However, the interactions between the OA/DTX toxins and phosphatases are not fully understood. This study sought to identify phosphatase targets and characterize their structure-activity relationships (SAR) with these algal toxins using a combination of phosphatase activity and cytotoxicity assays. Preliminary screening of 21 human and yeast phosphatases indicated that only three ser/thr PPs (PP2a, PP1, PP5) were inhibited by physiologically saturating concentrations of DTX2 (200 nM). SAR studies employed naturally-isolated OA, DTX1, and DTX2, which vary in degree and/or position of methylation, in addition to synthetic 2- epi -DTX2. OA/DTX analogs induced cytotoxicity and inhibited PP activity with a relatively conserved order of potency: OA = DTX1 ≥ DTX2 > 2- epi -DTX. The PPs were also differentially inhibited with sensitivities of PP2a > PP5 > PP1. These findings demonstrate that small variations in OA/DTX toxin structures, particularly at the head region (i.e., C1/C2), result in significant changes in toxicological potency, whereas changes in methylation at C31 and C35 (tail region) only mildly affect potency. In addition to this being the first study to extensively test OA/DTX analogs' activities towards PP5, these data will be helpful for accurately determining toxic equivalence factors (TEFs), facilitating molecular modeling efforts, and developing highly selective phosphatase inhibitors.

Structural basis of regulation and substrate specificity of protein kinase CK2 deduced from the modeling of protein-protein interactions

PubMed Central

Rekha, Nambudiry; Srinivasan, N

2003-01-01

Background Protein Kinase Casein Kinase 2 (PKCK2) is an ubiquitous Ser/Thr kinase expressed in all eukaryotes. It phosphorylates a number of proteins involved in various cellular processes. PKCK2 holoenzyme is catalytically active tetramer, composed of two homologous or identical and constitutively active catalytic (α) and two identical regulatory (β) subunits. The tetramer cannot phosphorylate some substrates that can be phosphorylated by PKCK2α in isolation. The present work explores the structural basis of this feature using computational analysis and modeling. Results We have initially built a model of PKCK2α bound to a substrate peptide with a conformation identical to that of the substrates in the available crystal structures of other kinases complexed with the substrates/ pseudosubstrates. In this model however, the fourth acidic residue in the consensus pattern of the substrate, S/T-X-X-D/E where S/T is the phosphorylation site, did not result in interaction with the active form of PKCK2α and is highly solvent exposed. Interaction of the acidic residue is observed if the substrate peptide adopts conformations as seen in β turn, α helix, or 310 helices. This type of conformation is observed and accommodated well by PKCK2α in calmodulin where the phosphorylation site is at the central helix. PP2A carries sequence patterns for PKCK2α phosphorylation. While the possibility of PP2A being phosphorylated by PKCK2 has been raised in the literature we use the model of PP2A to generate a model of PP2A-PKCK2α complex. PKCK2β undergoes phosphorylation by holoenzyme at the N-terminal region, and is accommodated very well in the limited space available at the substrate-binding site of the holoenzyme while the space is insufficient to accommodate the binding of PP2A or calmodulin in the holoenzyme. Conclusion Charge and shape complimentarity seems to play a role in substrate recognition and binding to PKCK2α, along with the consensus pattern. The detailed conformation of the substrate peptide binding to PKCK2 differs from the conformation of the substrate/pseudo substrate peptide that is bound to other kinases in the crystal structures reported. The ability of holoenzyme to phosphorylate substrate proteins seems to depend on the accessibility of the P-site in limited space available in holoenzyme. PMID:12740046

Grape Polyphenols Prevent Fructose-Induced Oxidative Stress and Insulin Resistance in First-Degree Relatives of Type 2 Diabetic Patients

PubMed Central

Hokayem, Marie; Blond, Emilie; Vidal, Hubert; Lambert, Karen; Meugnier, Emmanuelle; Feillet-Coudray, Christine; Coudray, Charles; Pesenti, Sandra; Luyton, Cedric; Lambert-Porcheron, Stéphanie; Sauvinet, Valerie; Fedou, Christine; Brun, Jean-Frédéric; Rieusset, Jennifer; Bisbal, Catherine; Sultan, Ariane; Mercier, Jacques; Goudable, Joelle; Dupuy, Anne-Marie; Cristol, Jean-Paul; Laville, Martine; Avignon, Antoine

2013-01-01

OBJECTIVE To assess the clinical efficacy of nutritional amounts of grape polyphenols (PPs) in counteracting the metabolic alterations of high-fructose diet, including oxidative stress and insulin resistance (IR), in healthy volunteers with high metabolic risk. RESEARCH DESIGN AND METHODS Thirty-eight healthy overweight/obese first-degree relatives of type 2 diabetic patients (18 men and 20 women) were randomized in a double-blind controlled trial between a grape PP (2 g/day) and a placebo (PCB) group. Subjects were investigated at baseline and after 8 and 9 weeks of supplementation, the last 6 days of which they all received 3 g/kg fat-free mass/day of fructose. The primary end point was the protective effect of grape PPs on fructose-induced IR. RESULTS In the PCB group, fructose induced 1) a 20% decrease in hepatic insulin sensitivity index (P < 0.05) and an 11% decrease in glucose infusion rate (P < 0.05) as evaluated during a two-step hyperinsulinemic-euglycemic clamp, 2) an increase in systemic (urinary F2-isoprostanes) and muscle (thiobarbituric acid–reactive substances and protein carbonylation) oxidative stress (P < 0.05), and 3) a downregulation of mitochondrial genes and decreased mitochondrial respiration (P < 0.05). All the deleterious effects of fructose were fully blunted by grape PP supplementation. Antioxidative defenses, inflammatory markers, and main adipokines were affected neither by fructose nor by grape PPs. CONCLUSIONS A natural mixture of grape PPs at nutritional doses efficiently prevents fructose-induced oxidative stress and IR. The current interest in grape PP ingredients and products by the global food and nutrition industries could well make them a stepping-stone of preventive nutrition. PMID:23275372

Folic Acid Reduces Tau Phosphorylation by Regulating PP2A Methylation in Streptozotocin-Induced Diabetic Mice

PubMed Central

Zheng, Miaoyan; Zou, Chen; Li, Mengyue; Huang, Guowei; Gao, Yuxia; Liu, Huan

2017-01-01

High incidence rate of Alzheimer’s disease (AD) is observed in patients with type 2 diabetes. Aggregated β-amyloid (Aβ) and hyperphosphorylated tau are the hallmarks of AD. Hyperphosphorylated tau has been detected in diabetic animals as well as in diabetic patients. Folates mediate the transfer of one carbon unit, required in various biochemical reactions. The effect of folate on tau phosphorylation in diabetic models still remains unknown. In this study, we investigated the effect and mechanism of folic acid on hyperphosphorylation of tau in streptozotocin (STZ)-induced diabetic mice. Diabetic mice induced by STZ, at the age of 10 weeks, were administered with three levels of folic acid: folic acid-deficient diet, diet with normal folic acid content, and 120 μg/kg folic acid diet for 8 weeks. Levels of serum folate and blood glucose were monitored. Tau phosphorylation, protein phosphatase 2A (PP2A) methylation, and Glycogen synthase kinase 3β (GSK-3β) phosphorylation were detected using Western blot. The S-adenosyl methionine:S-adenosyl homocysteine ratio (SAM:SAH) in brain tissues was also determined. DNA methyltransferase (DNMT) mRNA expression levels were detected using real-time PCR. Folic acid reduced tau hyperphosphorylation at Ser396 in the brain of diabetes mellitus (DM) mice. In addition, PP2A methylation and DNMT1 mRNA expression were significantly increased in DM mice post folic acid treatment. GSK-3β phosphorylation was not regulated by folic acid administration. Folic acid can reduce tau phosphorylation by regulating PP2A methylation in diabetic mice. These results support that folic acid can serve as a multitarget neuronal therapeutic agent for treating diabetes-associated cognitive dysfunction. PMID:28422052

PP2A: more than a reset switch to activate pRB proteins during the cell cycle and in response to signaling cues

PubMed Central

Kurimchak, Alison; Graña, Xavier

2015-01-01

In their active hypophosphorylated state, members of the retinoblastoma family of pocket proteins negatively regulate cell cycle progression at least in part by repressing expression of E2F-dependent genes. Mitogen-dependent activation of G1 and G1/S Cyclin Dependent Kinases (CDKs) results in coordinated hyperphosphorylation and inactivation of these proteins, which no longer bind and repress E2Fs. S and G2/M CDKs maintain pocket protein hyperphosphorylated through the end of mitosis. The inactivating action of inducible CDKs is opposed by the Ser/Thr protein phosphatases PP2A and PP1. Various trimeric PP2A holoenzymes have been implicated in dephosphorylation of pocket proteins in response to specific cellular signals and stresses or as part of an equilibrium with CDKs throughout the cell cycle. PP1 has specifically been implicated in dephosphorylation of pRB in late mitosis and early G1. This review is particularly focused on the emerging role of PP2A as a major hub for integration of growth suppressor signals that require rapid inactivation of pocket proteins. Of note, activation of particular PP2A holoenzymes triggers differential activation of pocket proteins in the presence of active CDKs.

Protein phosphatase 2A mediates resensitization of the neurokinin 1 receptor

PubMed Central

Murphy, Jane E.; Roosterman, Dirk; Cottrell, Graeme S.; Padilla, Benjamin E.; Feld, Micha; Brand, Eva; Cedron, Wendy J.; Steinhoff, Martin

2011-01-01

Activated G protein-coupled receptors (GPCRs) are phosphorylated and interact with β-arrestins, which mediate desensitization and endocytosis. Endothelin-converting enzyme-1 (ECE-1) degrades neuropeptides in endosomes and can promote recycling. Although endocytosis, dephosphorylation, and recycling are accepted mechanisms of receptor resensitization, a large proportion of desensitized receptors can remain at the cell surface. We investigated whether reactivation of noninternalized, desensitized (phosphorylated) receptors mediates resensitization of the substance P (SP) neurokinin 1 receptor (NK1R). Herein, we report a novel mechanism of resensitization by which protein phosphatase 2A (PP2A) is recruited to dephosphorylate noninternalized NK1R. A desensitizing concentration of SP reduced cell-surface SP binding sites by only 25%, and SP-induced Ca2+ signals were fully resensitized before cell-surface binding sites started to recover, suggesting resensitization of cell-surface-retained NK1R. SP induced association of β-arrestin1 and PP2A with noninternalized NK1R. β-Arrestin1 small interfering RNA knockdown prevented SP-induced association of cell-surface NK1R with PP2A, indicating that β-arrestin1 mediates this interaction. ECE-1 inhibition, by trapping β-arrestin1 in endosomes, also impeded SP-induced association of cell-surface NK1R with PP2A. Resensitization of NK1R signaling required both PP2A and ECE-1 activity. Thus, after stimulation with SP, PP2A interacts with noninternalized NK1R and mediates resensitization. PP2A interaction with NK1R requires β-arrestin1. ECE-1 promotes this process by releasing β-arrestin1 from NK1R in endosomes. These findings represent a novel mechanism of PP2A- and ECE-1-dependent resensitization of GPCRs. PMID:21795521

Protein phosphatase 2A mediates JS-K-induced apoptosis by affecting Bcl-2 family proteins in human hepatocellular carcinoma HepG2 cells.

PubMed

Liu, Ling; Huang, Zile; Chen, Jingjing; Wang, Jiangang; Wang, Shuying

2018-04-25

Protein phosphatase 2A (PP2A) is an important enzyme within various signal transduction pathways. The present study was investigated PP2A mediates JS-K-induced apoptosis by affecting Bcl-2 family protein. JS-K showed diverse inhibitory effects in five HCC cell lines, especially HepG2 cells. JS-K caused a dose- and time-dependent reduction in cell viability and increased in levels of LDH release. Meanwhile, JS-K- induced apoptosis was characterized by mitochondrial membrane potential reduction, Hoechst 33342 + /PI + dual staining, release of cytochrome c (Cyt c), and activation of cleaved caspase-9/3. Moreover, JS-K-treatment could lead to the activation of protein phosphatase 2A-C (PP2A-C), decrease of anti-apoptotic Bcl-2 family-protein expression including p-Bcl-2 (Ser70), Bcl-2, Bcl-xL, and Mcl-1 as well as the increase of pro-apoptosis Bcl-2 family-protein including Bim, Bad, Bax, and Bak. Furthermore, JS-K caused a marked increase of intracellular NO levels while pre-treatment with Carboxy-PTIO (a NO scavenger) reduced the cytotoxicity effects and the apoptosis rate. Meanwhile, pre-treatment with Carboxy-PTIO attenuated the JS-K-induced up-regulation of PP2A, Cyt c, and cleaved-caspase-9/3 activation. The silencing PP2A-C by siRNA could abolish the activation of PP2A-C, down-regulation of anti-apoptotic Bcl-2 family-protein (p-Bcl-2, Bcl-2, Bcl-xL, and Mcl-1), increase of pro-apoptosis Bcl-2 family-protein (Bim, Bad, Bax, and Bak) and apoptotic-related protein (Cyt c, cleaved caspase-9/3) that were caused by JS-K in HepG2 cells. In addition, pre-treatment with OA (a PP2A inhibitor) also attenuated the above effects induced by JS-K. In summary, NO release from JS-K induces apoptosis through PP2A activation, which contributed to the regulation of Bcl-2 family proteins. © 2018 Wiley Periodicals, Inc.

ABA signaling in guard cells entails a dynamic protein-protein interaction relay from the PYL-RCAR family receptors to ion channels.

PubMed

Lee, Sung Chul; Lim, Chae Woo; Lan, Wenzhi; He, Kai; Luan, Sheng

2013-03-01

Plant hormone abscisic acid (ABA) serves as an integrator of environmental stresses such as drought to trigger stomatal closure by regulating specific ion channels in guard cells. We previously reported that SLAC1, an outward anion channel required for stomatal closure, was regulated via reversible protein phosphorylation events involving ABA signaling components, including protein phosphatase 2C members and a SnRK2-type kinase (OST1). In this study, we reconstituted the ABA signaling pathway as a protein-protein interaction relay from the PYL/RCAR-type receptors, to the PP2C-SnRK2 phosphatase-kinase pairs, to the ion channel SLAC1. The ABA receptors interacted with and inhibited PP2C phosphatase activity against the SnRK2-type kinase, releasing active SnRK2 kinase to phosphorylate, and activate the SLAC1 channel, leading to reduced guard cell turgor and stomatal closure. Both yeast two-hybrid and bimolecular fluorescence complementation assays were used to verify the interactions among the components in the pathway. These biochemical assays demonstrated activity modifications of phosphatases and kinases by their interaction partners. The SLAC1 channel activity was used as an endpoint readout for the strength of the signaling pathway, depending on the presence of different combinations of signaling components. Further study using transgenic plants overexpressing one of the ABA receptors demonstrated that changing the relative level of interacting partners would change ABA sensitivity.

Optical characterization of CdS nanoparticles embedded into the comb-type amphiphilic graft copolymer

NASA Astrophysics Data System (ADS)

Kalaycı, Özlem A.; Duygulu, Özgür; Hazer, Baki

2013-01-01

This study refers to the synthesis and characterization of a novel organic/inorganic hybrid nanocomposite material containing cadmium sulfide (CdS) nanoparticles. For this purpose, a series of polypropylene (PP)-g-polyethylene glycol (PEG), PP-g-PEG comb-type amphiphilic graft copolymers were synthesized. PEGs with Mn = 400, 2000, 3350, and 8000 Da were used and the graft copolymers obtained were coded as PPEG400, PPEG2000, PPEG3350, and PPEG8000. CdS nanoparticles were formed in tetrahydrofuran solution of PP-g-PEG amphiphilic comb-type copolymer by the reaction between aqueous solutions of Na2S and Cd(CH3COO)2 simultaneously. Micelle formation of PPEG2000 comb-type amphiphilic graft copolymer in both solvent/non-solvent (petroleum ether-THF) by transmission electron microscopy (TEM). The optical characteristics, size morphology, phase analysis, and dispersion of CdS nanoparticles embedded in PPEG400, PPEG2000, PPEG3350, and PPEG8000 comb-type amphiphilic graft copolymer micelles were determined by high resolution TEM (HRTEM), energy dispersive spectroscopy, UV-vis spectroscopy, and fluorescence emission spectroscopy techniques. The aggregate size of PPEG2000-CdS is between 10 and 50 nm; however, in the case of PPEG400-CdS, PPEG3350-CdS, and PPEG8000-CdS samples, it is up to approximately 100 nm. The size of CdS quantum dots in the aggregates for PPEG2000 and PPEG8000 samples was observed as 5 nm by HRTEM analysis, and this result was also supported by UV-vis absorbance spectra and fluorescence emission spectra.

Testing hydrodynamic descriptions of p+p collisions at $$\\sqrt{s}=7$$ TeV

DOE PAGES

Habich, M.; Miller, G. A.; Romatschke, Paul; ...

2016-07-19

In high-energy collisions of heavy ions, experimental findings of collective flow are customarily associated with the presence of a thermalized medium expanding according to the laws of hydrodynamics. Recently, the ATLAS, CMS, and ALICE experiments found signals of the same type and magnitude in ultrarelativistic proton-proton collisions. In this study, the state-of-the-art hydrodynamic model SONIC is used to simulate the systems created in p+p collisions. By varying the size of the second-order transport coefficients, the range of applicability of hydrodynamics itself to the systems created in p+p collisions is quantified. It is found that hydrodynamics can give quantitatively reliable resultsmore » for the particle spectra and the elliptic momentum anisotropy coefficient v 2. As a result, using a simple geometric model of the proton based on the elastic form factor leads to results of similar type and magnitude to those found in experiment when allowing for a small bulk viscosity coefficient.« less

Phrase Length and Prosody in On-Line Ambiguity Resolution

ERIC Educational Resources Information Center

Webman-Shafran, Ronit; Fodor, Janet Dean

2016-01-01

We investigated the processing of ambiguous double-PP constructions in Hebrew. Selection restrictions forced the first prepositional phrase (PP1) to attach low, but PP2 could attach maximally high to VP or maximally low to the NP inside PP1. A length contrast in PP2 was also examined. This construction affords more potential locations for prosodic…

Expression analysis revealing destabilizing mutations in phosphomannomutase 2 deficiency (PMM2-CDG): expression analysis of PMM2-CDG mutations.

PubMed

Vega, Ana Isabel; Pérez-Cerdá, Celia; Abia, David; Gámez, Alejandra; Briones, Paz; Artuch, Rafael; Desviat, Lourdes R; Ugarte, Magdalena; Pérez, Belén

2011-08-01

Deficiency of phosphomannomutase (PMM2, MIM#601785) is the most common congenital disorder of glycosylation. Herein we report the genetic analysis of 22 Spanish PMM2 deficient patients and the functional analysis of 14 nucleotide changes in a prokaryotic expression system in order to elucidate their molecular pathogenesis. PMM2 activity assay revealed the presence of six protein changes with no enzymatic activities (p.R123Q, p.R141H, p.F157S, p.P184T, p.F207S and p.D209G) and seven mild protein changes with residual activities ranging from 16 to 54% (p.L32R, p.V44A p.D65Y, p.P113L p.T118S, p.T237M and p.C241S) and also one variant change with normal activity (p.E197A). The results obtained from Western blot analysis, degradation time courses of 11 protein changes and structural analysis of the PMM2 protein, suggest that the loss-of-function of most mutant proteins is based on their increased susceptibility to degradation or aggregation compared to the wild type protein, considering PMM2 deficiency as a conformational disease. We have identified exclusively catalytic protein change (p.D209G), catalytic protein changes affecting protein stability (p.R123Q and p.R141H), two protein changes disrupting the dimer interface (p.P113L and p.T118S) and several misfolding changes (p.L32R, p.V44A, p.D65Y, p.F157S, p.P184T, p.F207S, p.T237M and p.C241S). Our current work opens a promising therapeutic option using pharmacological chaperones to revert the effect of the characterized misfolding mutations identified in a wide range of PMM2 deficient patients.

The Effect of Preheat Temperature and Inter-Pass Reheating on Microstructure and Texture Evolution During Hot Rolling of Ti-6Al-4V (Preprint)

DTIC Science & Technology

2008-02-01

three broad types of microstructures can be developed in alpha/beta titanium alloys by TMP [2- 4 ], namely, fully lamellar, fully equiaxed, and...32-45. 4 . M. Peters, G. Luetjering, in: Titanium 80: Science and Technology, ed. H. Kimura and O. Izumi, Kyoto, Japan, 1980, pp. 925-938. 5. G...Lutjering, J.C. Williams, in: Titanium , Springer-Verlag, Berlin, Germany, 2003, pp.220- 224. 6 . A.A. Salem, M.G. Glavicic, S.L. Semiatin, Materials

Effects of permafrost melting on CO2 and CH4 exchange of a poorly drained black spruce lowland

USGS Publications Warehouse

Wickland, K.P.; Striegl, Robert G.; Neff, J.C.; Sachs, T.

2006-01-01

Permafrost melting is occurring in areas of the boreal forest region where large amounts of carbon (C) are stored in organic soils. We measured soil respiration, net CO2 flux, and net CH4 flux during May-September 2003 and March 2004 in a black spruce lowland in interior Alaska to better understand how permafrost thaw in poorly drained landscapes affects land-atmosphere CO2 and CH4 exchange. Sites included peat soils underlain by permafrost at ???0.4 m depth (permafrost plateau, PP), four thermokarst wetlands (TW) having no permafrost in the upper 2.2 m, and peat soils bordering the thermokarst wetlands having permafi7ost at ???0.5 in depth (thermokarst edges, TE). Soil respiration rates were not significantly different among the sites, and 5-cm soil temperature explained 50-91% of the seasonal variability in soil respiration within the sites. Groundcover vegetation photosynthesis (calculated as net CO2 minus soil respiration) was significantly different among the sites (TW > TE > PP), which can be partly attributed to the difference in photosynthetically active radiation reaching the ground at each site type. Methane emission rates were 15 to 28 times greater fi7om TW than from TE and PP. We modeled annual soil respiration and groundcover vegetation photosynthesis using soil temperature and radiation data, and CH4 flux by linear interpolation. We estimated all sites as net C gas sources to the atmosphere (not including tree CO2 uptake at PP and TE), although the ranges in estimates when accounting for errors were large enough that TE and TW may have been net C sinks. Copyright 2006 by the American Geophysical Union.

Ketamine, a Clinically Used Anesthetic, Inhibits Vascular Smooth Muscle Cell Proliferation via PP2A-Activated PI3K/Akt/ERK Inhibition

PubMed Central

Chang, Yi; Li, Jiun-Yi; Jayakumar, Thanasekaran; Hung, Shou-Huang; Lee, Wei-Cheng; Manubolu, Manjunath; Sheu, Joen-Rong; Hsu, Ming-Jen

2017-01-01

Abnormal proliferation of vascular smooth muscle cells (VSMCs) gives rise to major pathological processes involved in the development of cardiovascular diseases. The use of anti-proliferative agents for VSMCs offers potential for the treatment of vascular disorders. Intravenous anesthetics are firmly established to have direct effects on VSMCs, resulting in modulation of blood pressure. Ketamine has been used for many years in the intensive care unit (ICU) for sedation, and has recently been considered for adjunctive therapy. In the present study, we investigated the effects of ketamine on platelet-derived growth factor BB (PDGF-BB)-induced VSMC proliferation and the associated mechanism. Ketamine concentration-dependently inhibited PDGF-BB-induced VSMC proliferation without cytotoxicity, and phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated protein kinase (ERK) inhibitors, LY294002 and PD98059, respectively, have similar inhibitory effects. Ketamine was shown to attenuate PI3K, Akt, and ERK1/2 phosphorylation induced by PDGF-BB. Okadaic acid, a selective protein phosphatase 2A (PP2A) inhibitor, significantly reversed ketamine-mediated PDGF-BB-induced PI3K, Akt, and ERK1/2 phosphorylation; a transfected protein phosphatse 2a (pp2a) siRNA reversed Akt and ERK1/2 phosphorylation; and 3-O-Methyl-sphingomyeline (3-OME), an inhibitor of sphingomyelinase, also significantly reversed ERK1/2 phosphorylation. Moreover, ketamine alone significantly inhibited tyrosine phosphorylation and demethylation of PP2A in a concentration-dependent manner. In addition, the pp2a siRNA potently reversed the ketamine-activated catalytic subunit (PP2A-C) of PP2A. These results provide evidence of an anti-proliferating effect of ketamine in VSMCs, showing activation of PP2A blocks PI3K, Akt, and ERK phosphorylation that subsequently inhibits the proliferation of VSMCs. Thus, ketamine may be considered a potential effective therapeutic agent for reducing atherosclerotic process by blocking the proliferation of VSMCs. PMID:29186909

Ketamine, a Clinically Used Anesthetic, Inhibits Vascular Smooth Muscle Cell Proliferation via PP2A-Activated PI3K/Akt/ERK Inhibition.

PubMed

Chang, Yi; Li, Jiun-Yi; Jayakumar, Thanasekaran; Hung, Shou-Huang; Lee, Wei-Cheng; Manubolu, Manjunath; Sheu, Joen-Rong; Hsu, Ming-Jen

2017-11-27

Abnormal proliferation of vascular smooth muscle cells (VSMCs) gives rise to major pathological processes involved in the development of cardiovascular diseases. The use of anti-proliferative agents for VSMCs offers potential for the treatment of vascular disorders. Intravenous anesthetics are firmly established to have direct effects on VSMCs, resulting in modulation of blood pressure. Ketamine has been used for many years in the intensive care unit (ICU) for sedation, and has recently been considered for adjunctive therapy. In the present study, we investigated the effects of ketamine on platelet-derived growth factor BB (PDGF-BB)-induced VSMC proliferation and the associated mechanism. Ketamine concentration-dependently inhibited PDGF-BB-induced VSMC proliferation without cytotoxicity, and phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated protein kinase (ERK) inhibitors, LY294002 and PD98059, respectively, have similar inhibitory effects. Ketamine was shown to attenuate PI3K, Akt, and ERK1/2 phosphorylation induced by PDGF-BB. Okadaic acid, a selective protein phosphatase 2A (PP2A) inhibitor, significantly reversed ketamine-mediated PDGF-BB-induced PI3K, Akt, and ERK1/2 phosphorylation; a transfected protein phosphatse 2a ( pp2a ) siRNA reversed Akt and ERK1/2 phosphorylation; and 3-O-Methyl-sphingomyeline (3-OME), an inhibitor of sphingomyelinase, also significantly reversed ERK1/2 phosphorylation. Moreover, ketamine alone significantly inhibited tyrosine phosphorylation and demethylation of PP2A in a concentration-dependent manner. In addition, the pp2a siRNA potently reversed the ketamine-activated catalytic subunit (PP2A-C) of PP2A. These results provide evidence of an anti-proliferating effect of ketamine in VSMCs, showing activation of PP2A blocks PI3K, Akt, and ERK phosphorylation that subsequently inhibits the proliferation of VSMCs. Thus, ketamine may be considered a potential effective therapeutic agent for reducing atherosclerotic process by blocking the proliferation of VSMCs.

Carfilzomib induces leukaemia cell apoptosis via inhibiting ELK1/KIAA1524 (Elk-1/CIP2A) and activating PP2A not related to proteasome inhibition.

PubMed

Liu, Chun-Yu; Hsieh, Feng-Shu; Chu, Pei-Yi; Tsai, Wen-Chun; Huang, Chun-Teng; Yu, Yuan-Bin; Huang, Tzu-Ting; Ko, Po-Shen; Hung, Man-Hsin; Wang, Wan-Lun; Shiau, Chung-Wai; Chen, Kuen-Feng

2017-06-01

Enhancing the tumour suppressive activity of protein phosphatase 2A (PP2A) has been suggested to be an anti-leukaemic strategy. KIAA1524 (also termed CIP2A), an oncoprotein inhibiting PP2A, is associated with disease progression in chronic myeloid leukaemia and may be prognostic in cytogenetically normal acute myeloid leukaemia. Here we demonstrated that the selective proteasome inhibitor, carfilzomib, induced apoptosis in sensitive primary leukaemia cells and in sensitive leukaemia cell lines, associated with KIAA1524 protein downregulation, increased PP2A activity and decreased p-Akt, but not with the proteasome inhibition effect of carfilzomib. Ectopic expression of KIAA1524, or pretreatment with the PP2A inhibitor, okadaic acid, suppressed carfilzomib-induced apoptosis and KIAA1524 downregulation in sensitive cells, whereas co-treatment with the PP2A agonist, forskolin, enhanced carfilzomib-induced apoptosis in resistant cells. Mechanistically, carfilzomib affected KIAA1524 transcription through disturbing ELK1 (Elk-1) binding to the KIAA1524 promoter. Moreover, the drug sensitivity and mechanism of carfilzomib in xenograft mouse models correlated well with the effects of carfilzomib on KIAA1524 and p-Akt expression, as well as PP2A activity. Our data disclosed a novel drug mechanism of carfilzomib in leukaemia cells and suggests the potential therapeutic implication of KIAA1524 in leukaemia treatment. © 2017 John Wiley & Sons Ltd.

PP2B and PP1α cooperatively disrupt 7SK snRNP to release P-TEFb for transcription in response to Ca2+ signaling

PubMed Central

Chen, Ruichuan; Liu, Min; Li, Huan; Xue, Yuhua; Ramey, Wanichaya N.; He, Nanhai; Ai, Nanping; Luo, Haohong; Zhu, Ying; Zhou, Nan; Zhou, Qiang

2008-01-01

The positive transcription elongation factor b (P-TEFb), consisting of Cdk9 and cyclin T, stimulates RNA polymerase II elongation and cotranscriptional pre-mRNA processing. To accommodate different growth conditions and transcriptional demands, a reservoir of P-TEFb is kept in an inactive state in the multisubunit 7SK snRNP. Under certain stress or disease conditions, P-TEFb is released to activate transcription, although the signaling pathway(s) that controls this is largely unknown. Here, through analyzing the UV- or hexamethylene bisacetamide (HMBA)-induced release of P-TEFb from 7SK snRNP, an essential role for the calcium ion (Ca2+)–calmodulin–protein phosphatase 2B (PP2B) signaling pathway is revealed. However, Ca2+ signaling alone is insufficient, and PP2B must act sequentially and cooperatively with protein phosphatase 1α (PP1α) to disrupt 7SK snRNP. Activated by UV/HMBA and facilitated by a PP2B-induced conformational change in 7SK snRNP, PP1α releases P-TEFb through dephosphorylating phospho-Thr186 in the Cdk9 T-loop. This event is also necessary for the subsequent recruitment of P-TEFb by the bromodomain protein Brd4 to the preinitiation complex, where Cdk9 remains unphosphorylated and inactive until after the synthesis of a short RNA. Thus, through cooperatively dephosphorylating Cdk9 in response to Ca2+ signaling, PP2B and PP1α alter the P-TEFb functional equilibrium through releasing P-TEFb from 7SK snRNP for transcription. PMID:18483222

Essential requirement for PP2A inhibition by the oncogenic receptor c-KIT suggests PP2A reactivation as a strategy to treat c-KIT+ cancers

PubMed Central

Roberts, Kathryn G.; Smith, Amanda M.; McDougall, Fiona; Carpenter, Helen; Horan, Martin; Neviani, Paolo; Powell, Jason A.; Thomas, Daniel; Guthridge, Mark A.; Perrotti, Danilo; Sim, Alistair T.R.; Ashman, Leonie K.; Verrills, Nicole M.

2010-01-01

Oncogenic mutations of the receptor tyrosine kinase c-KIT play an important role in the pathogenesis of gastrointestinal stromal tumors (GIST), systemic mastocytosis, and some acute myeloid leukemias (AML). Whilst juxtamembrane mutations commonly detected in GIST are sensitive to tyrosine kinase inhibitors, the kinase domain mutations frequently encountered in systemic mastocytosis and AML confer resistance and are largely unresponsive to targeted inhibition by the existing agent imatinib. In this study we show that myeloid cells expressing activated c-KIT mutants that are imatinib-sensitive (V560G) or –resistant (D816V) can inhibit the tumor suppressor activity of protein phosphatase 2A (PP2A). This effect was associated with reduced expression of PP2A structural (A) and regulatory subunits (B55α; B56α; B56γ and B56δ). Overexpression of PP2A-Aα in D816V c-KIT cells induced apoptosis and inhibited proliferation. In addition, pharmacological activation of PP2A by FTY720 reduced proliferation, inhibited clonogenic potential and induced apoptosis of mutant c-KIT+ cells, whilst having no effect on WT c-KIT cells or empty vector controls. FTY720 treatment caused dephosphorylation of the D816V c-KIT receptor and its downstream signaling targets pAkt, pSTAT5 and pERK1/2. Additionally, in vivo administration of FTY720 delayed the growth of V560G and D816V c-KIT tumors, inhibited splenic and bone marrow infiltration, and prolonged survival. Our findings show that PP2A inhibition is essential for c-KIT-mediated tumorigenesis, and that reactivating PP2A may offer an attractive strategy to treat drug-resistant c-KIT+ cancers. PMID:20551067

Plasma fatty acid ethanolamides are associated with postprandial triglycerides, ApoCIII and ApoE in humans consuming high fructose corn syrup-sweetened beverage.

PubMed

Allister Price, Candice; Argueta, Donovan A; Medici, Valentina; Bremer, Andrew A; Lee, Vivien; Nunez, Marinelle V; Chen, Guoxia X; Keim, Nancy L; Havel, Peter J; Stanhope, Kimber L; DiPatrizio, Nicholas V

2018-04-10

Epidemiological and clinical research studies have provided ample evidence demonstrating that consumption of sugar-sweetened beverages (SSB) increases risk factors involved in the development of obesity, type 2 diabetes (T2D), and cardiovascular disease (CVD). Our previous study demonstrated that when compared to aspartame (Asp), two weeks of high-fructose corn syrup (HFCS)-sweetened beverages provided at 25% of daily energy requirement (Ereq) was associated with increased body weight, postprandial (pp) triglycerides (TG), and fasting and pp CVD risk factors in young adults. The fatty acid ethanolamide, anandamide (AEA), and the monoacylglycerol, 2-arachidonoyl-sn-glycerol (2-AG), are two primary endocannabinoids (ECs) that play a role in regulating food intake, increasing adipose storage, and regulating lipid metabolism. Therefore, we measured plasma concentrations of ECs and their analogs, oleoylethanolamide (OEA), docosahexaenoyl ethanolamide (DHEA), and docosahexaenoyl glycerol (DHG), in participants from our previous study who consumed HFCS- or Asp-sweetened beverages to determine associations with weight gain and CVD risk factors. Two-week exposure to either HFCS- or Asp-sweetened beverages resulted in significant differences in the changes in fasting levels of OEA and DHEA between groups after the testing period. Subjects who consumed Asp, but not HFCS, displayed a reduction in AEA, OEA and DHEA after the testing period. In contrast, there were significant positive relationships between AEA, OEA, and DHEA versus ppTG, ppApoCIII and ppApoE in those consuming HFCS, but not in those consuming Asp. Our findings reveal previously unknown associations between circulating ECs and EC-related molecules with markers of lipid metabolism and CVD risk after HFCS-consumption.

Protein phosphatase and kinase activities possibly involved in exocytosis regulation in Paramecium tetraurelia.

PubMed Central

Kissmehl, R; Treptau, T; Hofer, H W; Plattner, H

1996-01-01

In Paramecium tetraurelia cells synchronous exocytosis induced by aminoethyldextran (AED) is accompanied by an equally rapid dephosphorylation of a 63 kDa phosphoprotein (PP63) within 80 ms. In vivo, rephosphorylation occurs within a few seconds after AED triggering. In homogenates (P)P63 can be solubilized in all three phosphorylation states (phosphorylated, dephosphorylated and rephosphorylated) and thus tested in vitro. By using chelators of different divalent cations, de- and rephosphorylation of PP63 and P63 respectively can be achieved by an endogenous protein phosphatase/kinase system. Dephosphorylation occurs in the presence of EDTA, whereas in the presence of EGTA this was concealed by phosphorylation by endogenous kinase(s), thus indicating that phosphorylation of P63 is calcium-independent. Results obtained with protein phosphatase inhibitors (okadaic acid, calyculin A) allowed us to exclude a protein serine/threonine phosphatase of type I (with selective sensitivity in Paramecium). Protein phosphatase 2C is also less likely to be a candidate because of its requirement for high Mg2+ concentrations. According to previous evidence a protein serine/threonine phosphatase of type 2B (calcineurin; CaN) is possibly involved. We have now found that bovine brain CaN dephosphorylates PP63 in vitro. Taking into account the specific requirements of this phosphatase in vitro, with p-nitrophenyl phosphate as a substrate, we have isolated a cytosolic phosphatase of similar characteristics by combined preparative gel electrophoresis and affinity-column chromatography. In Paramecium this phosphatase also dephosphorylates PP63 in vitro (after 32P labelling in vivo). Using various combinations of ion exchange, affinity and hydrophobic interaction chromatography we have also isolated three different protein kinases from the soluble fraction, i.e. a cAMP-dependent protein kinase (PKA), a cGMP-dependent protein kinase (PKG) and a casein kinase. Among the kinases tested, PKA cannot phosphorylate P63, whereas either PKG or the casein kinase phosphorylate P63 in vitro. On the basis of these findings we propose that a protein phosphatase/kinase system is involved in the regulation of exocytosis in P. tetraurelia cells. PMID:8694788

Phagosomal pH and glass fiber dissolution in cultured nasal epithelial cells and alveolar macrophages: a preliminary study.

PubMed Central

Johnson, N F

1994-01-01

The dissolution rate of glass fibers has been shown to be pH sensitive using in vitro lung fluid simulant models. The current study investigated whether there is a difference in phagosomal pH (ppH) between rat alveolar macrophages (AM) and rat nasal epithelial cells (RNEC) and whether such a difference would influence the dissolution of glass fibers. The ppH was measured in cultured AM and RNEC using flow cytometric, fluorescence-emission rationing techniques with fluorescein-labeled, amorphous silica particles. Glass fiber dissolution was determined in AM and RNEC cultured for 3 weeks with fast dissolving glass fibers (GF-A) or slow dissolving ones (GF-B). The mean diameters of GF-A were 2.7 microns and of GF-B, 2.6 microns, the average length of both fibers was approximately 22 to 25 microns. Dissolution was monitored by measuring the length and diameter of intracellular fibers and estimating the volume, assuming a cylindrical morphology. The ppH of AM was 5.2 to 5.8, and the ppH of RNEC was 7.0 to 7.5. The GF-A dissolved more slowly in RNEC than in AM, and no dissolution was evident in either cell type with GF-B. The volume loss with GF-A after a 3-week culture with AM was 66% compared to 45% for cultured RNEC. These results are different from those obtained using in vitro lung fluid-simulant models where dissolution is faster at higher pH. This difference suggests that dissolution rates of glass fibers in AM should not be applied to the dissolution of fibers in epithelial cells. Images Figure 1. a Figure 1. b Figure 2. a Figure 2. b Figure 3. a Figure 3. b PMID:7882965

PP2A-activating drugs selectively eradicate TKI-resistant chronic myeloid leukemic stem cells

PubMed Central

Neviani, Paolo; Harb, Jason G.; Oaks, Joshua J.; Santhanam, Ramasamy; Walker, Christopher J.; Ellis, Justin J.; Ferenchak, Gregory; Dorrance, Adrienne M.; Paisie, Carolyn A.; Eiring, Anna M.; Ma, Yihui; Mao, Hsiaoyin C.; Zhang, Bin; Wunderlich, Mark; May, Philippa C.; Sun, Chaode; Saddoughi, Sahar A.; Bielawski, Jacek; Blum, William; Klisovic, Rebecca B.; Solt, Janelle A.; Byrd, John C.; Volinia, Stefano; Cortes, Jorge; Huettner, Claudia S.; Koschmieder, Steffen; Holyoake, Tessa L.; Devine, Steven; Caligiuri, Michael A.; Croce, Carlo M.; Garzon, Ramiro; Ogretmen, Besim; Arlinghaus, Ralph B.; Chen, Ching-Shih; Bittman, Robert; Hokland, Peter; Roy, Denis-Claude; Milojkovic, Dragana; Apperley, Jane; Goldman, John M.; Reid, Alistair; Mulloy, James C.; Bhatia, Ravi; Marcucci, Guido; Perrotti, Danilo

2013-01-01

The success of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) depends on the requirement for BCR-ABL1 kinase activity in CML progenitors. However, CML quiescent HSCs are TKI resistant and represent a BCR-ABL1 kinase–independent disease reservoir. Here we have shown that persistence of leukemic HSCs in BM requires inhibition of the tumor suppressor protein phosphatase 2A (PP2A) and expression — but not activity — of the BCR-ABL1 oncogene. Examination of HSCs from CML patients and healthy individuals revealed that PP2A activity was suppressed in CML compared with normal HSCs. TKI-resistant CML quiescent HSCs showed increased levels of BCR-ABL1, but very low kinase activity. BCR-ABL1 expression, but not kinase function, was required for recruitment of JAK2, activation of a JAK2/β-catenin survival/self-renewal pathway, and inhibition of PP2A. PP2A-activating drugs (PADs) markedly reduced survival and self-renewal of CML quiescent HSCs, but not normal quiescent HSCs, through BCR-ABL1 kinase–independent and PP2A-mediated inhibition of JAK2 and β-catenin. This led to suppression of human leukemic, but not normal, HSC/progenitor survival in BM xenografts and interference with long-term maintenance of BCR-ABL1–positive HSCs in serial transplantation assays. Targeting the JAK2/PP2A/β-catenin network in quiescent HSCs with PADs (e.g., FTY720) has the potential to treat TKI-refractory CML and relieve lifelong patient dependence on TKIs. PMID:23999433

Structure–Activity Relationship Studies Using Natural and Synthetic Okadaic Acid/Dinophysistoxin Toxins

PubMed Central

Twiner, Michael J.; Doucette, Gregory J.; Pang, Yucheng; Fang, Chao; Forsyth, Craig J.; Miles, Christopher O.

2016-01-01

Okadaic acid (OA) and the closely related dinophysistoxins (DTXs) are algal toxins that accumulate in shellfish and are known serine/threonine protein phosphatase (ser/thr PP) inhibitors. Phosphatases are important modulators of enzyme activity and cell signaling pathways. However, the interactions between the OA/DTX toxins and phosphatases are not fully understood. This study sought to identify phosphatase targets and characterize their structure–activity relationships (SAR) with these algal toxins using a combination of phosphatase activity and cytotoxicity assays. Preliminary screening of 21 human and yeast phosphatases indicated that only three ser/thr PPs (PP2a, PP1, PP5) were inhibited by physiologically saturating concentrations of DTX2 (200 nM). SAR studies employed naturally-isolated OA, DTX1, and DTX2, which vary in degree and/or position of methylation, in addition to synthetic 2-epi-DTX2. OA/DTX analogs induced cytotoxicity and inhibited PP activity with a relatively conserved order of potency: OA = DTX1 ≥ DTX2 >> 2-epi-DTX. The PPs were also differentially inhibited with sensitivities of PP2a > PP5 > PP1. These findings demonstrate that small variations in OA/DTX toxin structures, particularly at the head region (i.e., C1/C2), result in significant changes in toxicological potency, whereas changes in methylation at C31 and C35 (tail region) only mildly affect potency. In addition to this being the first study to extensively test OA/DTX analogs’ activities towards PP5, these data will be helpful for accurately determining toxic equivalence factors (TEFs), facilitating molecular modeling efforts, and developing highly selective phosphatase inhibitors. PMID:27827901

Supercritical CO2 foaming of radiation crosslinked polypropylene/high-density polyethylene blend: Cell structure and tensile property

NASA Astrophysics Data System (ADS)

Yang, Chenguang; Xing, Zhe; Zhang, Mingxing; Zhao, Quan; Wang, Mouhua; Wu, Guozhong

2017-12-01

A blend of isotactic polypropylene (PP) with high-density polyethylene (HDPE) in different PP/HDPE ratios was irradiated by γ-ray to induce cross-linking and then foamed using supercritical carbon dioxide (scCO2) as a blowing agent. Radiation effect on the melting point and crystallinity were analyzed in detail. The average cell diameter and cell density were compared for PP/HDPE foams prepared under different conditions. The optimum absorbed dose for the scCO2 foaming of PP/HDPE in terms of foaming ability and cell structure was 20 kGy. Tensile measurements showed that the elongation at break and tensile strength at break of the crosslinked PP/HDPE foams were higher than the non-crosslinked ones. Of particular interest was the increase in the foaming temperature window from 4 ℃ for pristine PP to 8-12 ℃ for the radiation crosslinked PP/HDPE blends. This implies much easier handling of scCO2 foaming of crosslinked PP with the addition of HDPE.

Tripodal polyphosphine ligands as inductors of chelate ring-opening processes in mononuclear palladium(II) and platinum(II) compounds. The X-ray crystal structure of two derivatives containing dangling phosphorus.

PubMed

Fernández-Anca, Damián; García-Seijo, M Inés; García-Fernández, M Esther

2010-03-07

The reaction of NP(3) (tris[2-(diphenylphosphino)ethyl]amine and PP(3) (tris[2-(diphenylphosphino)ethyl]phosphine) with the five-coordinate complexes [PdCl(NP(3))]Cl (1) and [MX(PP(3))]X [M = Pd: X = Cl(2), Br(3), I(4); M = Pt: X = Cl(5), Br(6), I(7)], respectively, followed by (31)P{(1)H}NMR when X = Cl, led to the formation of unprecedented four-coordinate halides in a 1 : 2 metal to ligand ratio, [M(AP(3))(2)]X(2) [A = N, M = Pd: X = Cl(8); A = P, M = Pd: X = Cl(9), Br(10), I(11); A = P, M = Pt: X = Cl(12), Br(13), I (14)], containing reactive dangling phosphorus. Given the non characterised precursors [M(ONO(2))(PP(3))](NO(3))], the interaction between the heteronuclear species [MAg(NO(3))(3)(PP(3))] [M = Pd(15), Pt(16)] and PP(3) was explored. It was found that the addition of 1 equivalent of phosphine afforded [MAg(NO(3))(PP(3))(2)](NO(3))(2) [M = Pd(15*), Pt(16*)] containing Ag(I) bound to two dangling phosphorus while the reaction with 2 equivalents led to the complexes [M(PP(3))(2)](NO(3))(2) [M = Pd (17), Pt (18)] in coexistence with [Ag(2)(mu-PP(3))(2)](NO(3))(2). The fate of Ag(I) on the reaction of the mixed metal compounds with excess PP(3) consisted of preventing dissociation, observed in solution for halides, and acting as an assistant for crystallization. Colourless single crystals of 18 and 10, studied by X-ray diffraction, were afforded by reaction of 16 with 4 equivalents of PP(3) and from solutions of 10 in chloroform coexisting with red crystals of 3, respectively. The structures revealed the presence of dications [M(PP(3))(2)](2+) that show two five-membered chelate rings to M(II) in a square-planar arrangement and four uncoordinated phosphine arms with the counter anions being symmetrically placed at 4.431 (Br(-)) and 13.823 (NO(3)(-)) A from M(II) above and below its coordination, MP(4), plane. Complexes 9 and 12 were shown to undergo an interesting reactivity in solution versus group 11 monocations. The reactions consisted of conversions of the two five-membered chelate rings to M into three (structure I) or two (structure II) fused five-membered chelate rings, formation of species where Pt(II) retained its square-planar environment with the two dangling phosphine arms of each PP(3) bound to Cu(I) or Ag(I) (structure III) and complexes bearing distorted square-planar (P(2)MCl(2)) and presumably tetrahedral (AuP(4)+ P(2)AuCl(2)) arrangements (structure IV). The processes with Ag(I) salts also gave mixtures of I+III (chloride and nitrate) or II+III (nitrate).

Suppressor mutations identify amino acids in PAA-1/PR65 that facilitate regulatory RSA-1/B″ subunit targeting of PP2A to centrosomes in C. elegans

PubMed Central

Lange, Karen I.; Heinrichs, Jeffrey; Cheung, Karen; Srayko, Martin

2013-01-01

Summary Protein phosphorylation and dephosphorylation is a key mechanism for the spatial and temporal regulation of many essential developmental processes and is especially prominent during mitosis. The multi-subunit protein phosphatase 2A (PP2A) enzyme plays an important, yet poorly characterized role in dephosphorylating proteins during mitosis. PP2As are heterotrimeric complexes comprising a catalytic, structural, and regulatory subunit. Regulatory subunits are mutually exclusive and determine subcellular localization and substrate specificity of PP2A. At least 3 different classes of regulatory subunits exist (termed B, B′, B″) but there is no obvious similarity in primary sequence between these classes. Therefore, it is not known how these diverse regulatory subunits interact with the same holoenzyme to facilitate specific PP2A functions in vivo. The B″ family of regulatory subunits is the least understood because these proteins lack conserved structural domains. RSA-1 (regulator of spindle assembly) is a regulatory B″ subunit required for mitotic spindle assembly in Caenorhabditis elegans. In order to address how B″ subunits interact with the PP2A core enzyme, we focused on a conditional allele, rsa-1(or598ts), and determined that this mutation specifically disrupts the protein interaction between RSA-1 and the PP2A structural subunit, PAA-1. Through genetic screening, we identified a putative interface on the PAA-1 structural subunit that interacts with a defined region of RSA-1/B″. In the context of previously published results, these data propose a mechanism of how different PP2A B-regulatory subunit families can bind the same holoenzyme in a mutually exclusive manner, to perform specific tasks in vivo. PMID:23336080

Suppressor mutations identify amino acids in PAA-1/PR65 that facilitate regulatory RSA-1/B″ subunit targeting of PP2A to centrosomes in C. elegans.

PubMed

Lange, Karen I; Heinrichs, Jeffrey; Cheung, Karen; Srayko, Martin

2013-01-15

Protein phosphorylation and dephosphorylation is a key mechanism for the spatial and temporal regulation of many essential developmental processes and is especially prominent during mitosis. The multi-subunit protein phosphatase 2A (PP2A) enzyme plays an important, yet poorly characterized role in dephosphorylating proteins during mitosis. PP2As are heterotrimeric complexes comprising a catalytic, structural, and regulatory subunit. Regulatory subunits are mutually exclusive and determine subcellular localization and substrate specificity of PP2A. At least 3 different classes of regulatory subunits exist (termed B, B', B″) but there is no obvious similarity in primary sequence between these classes. Therefore, it is not known how these diverse regulatory subunits interact with the same holoenzyme to facilitate specific PP2A functions in vivo. The B″ family of regulatory subunits is the least understood because these proteins lack conserved structural domains. RSA-1 (regulator of spindle assembly) is a regulatory B″ subunit required for mitotic spindle assembly in Caenorhabditis elegans. In order to address how B″ subunits interact with the PP2A core enzyme, we focused on a conditional allele, rsa-1(or598ts), and determined that this mutation specifically disrupts the protein interaction between RSA-1 and the PP2A structural subunit, PAA-1. Through genetic screening, we identified a putative interface on the PAA-1 structural subunit that interacts with a defined region of RSA-1/B″. In the context of previously published results, these data propose a mechanism of how different PP2A B-regulatory subunit families can bind the same holoenzyme in a mutually exclusive manner, to perform specific tasks in vivo.

Uranium hydrogeochemical and stream sediment reconnaissance of the Cortez NTMS Quadrangle, Colorado/Utah, including concentrations of forty-three additional elements

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

Warren, R.G.

1979-05-01

During the summers of 1976, 1977, and 1978, 598 water and 1657 sediment samples were collected from 1775 locations within the 19,600-km/sup 2/ area of the Cortez Quadrangle, Colorado and Utah. Water samples were collected from streams, springs, and wells; sediment samples were collected from stream channels (wet and dry) and from springs. Each water sample was analyzed for 13 elements, and each sediment sample was analyzed for 43 elements. Uranium concentrations in water samples range from below the detection limit of 0.02 to 241.47 ppB and have a median of 0.87 ppB and a mean of 3.80 ppB. Backgroundmore » uranium concentrations are 2 to 5 ppB in several nonmountainous regions but are much lower in mountainous areas, particularly in the northeastern portion of the quadrangle. Water samples containing high uranium concentrations (>20 ppB) generally are associated with high conductivities, high concentrations of other metallic elements, and geologic units, such as the Mancos shale, that are unfavorable for uranium mineralization. However, four ground-water samples exhibit high uranium concentrations without concomitant high conductivities or high concentrations of other metallic elements. Two of these samples were collected from sites in the Slick Rock U--V district, and two were collected in the Morrison formation in the southern portion of the quadrangle where large uranium deposits are not known. Water samples collected from the northwestern corner of the quadrangle uniformly exhibit background uranium values but generally contain high nickel concentrations. In this area, U--Cu (White Canyon-type) deposits are hosted primarily by the Shinarump member of the Chinle formation. Uranium concentrations in sediment samples range from 0.51 to 76.41 ppM and have a median of 2.76 ppM and a mean of 3.08 ppM. Background uranium and metallic element concentrations decrease to the southwest from the highest values in the northeastern portion of the quadrangle.« less

Evaluation of the effect of organic pro-degradant concentration in polypropylene exposed to the natural ageing

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

Montagna, L. S., E-mail: larissambiental@yahoo.com.br, E-mail: andrecatto@terra.com.br, E-mail: katiandry@hotmail.com, E-mail: mmcforte@hotmail.com, E-mail: ruth.santana@ufrgs.br; Catto, A. L., E-mail: larissambiental@yahoo.com.br, E-mail: andrecatto@terra.com.br, E-mail: katiandry@hotmail.com, E-mail: mmcforte@hotmail.com, E-mail: ruth.santana@ufrgs.br; Rossini, K., E-mail: larissambiental@yahoo.com.br, E-mail: andrecatto@terra.com.br, E-mail: katiandry@hotmail.com, E-mail: mmcforte@hotmail.com, E-mail: ruth.santana@ufrgs.br

The production and consumption of plastics in the last decade has recorded a remarkable increase in the scientific and industrial interest in environmentally degradable polymer (EDPs). Polymers wastes are deposited improperly, such as dumps, landfills, rivers and seas, causing a serious problem by the accumulation in the environment. The abiotic processes, like the photodegradation, are the most efficient occurring in the open environmental, where the polymers undergo degradation from the action of sunlight that result from direct exposure to solar radiation, however depend of the type of chemical ageing, which is the principal component of climatic ageing. The subject ofmore » this work is to study the influence of concentration of organic pro-degradant (1, 2 and 3 % w/w) in the polypropylene (PP) exposed in natural ageing. PP samples with and without the additive were processed in plates square form, obtained by thermal compression molding (TCM) using a press at 200°C under 2 tons for 5 min, and then were exposed at natural ageing during 120 days. The presence of organic additive influenced on PP degradability, this fact was assessed by changes in the thermal and morphology properties of the samples after 120 days of natural ageing. Scanning Electronic Microscopy (SEM) results of the morphological surface of the modified PP samples showed greater degradation photochemical oxidative when compared to neat PP, due to increase of rugosity and formation of microvoids. PP samples with different pro-degradant concentration under natural ageing presented a degree of crystallinity, obtained by Differential Scanning Calorimeter (DSC) increases in comparing the neat PP.« less

Differential dephosphorylation of the insulin receptor and its 160-kDa substrate (pp160) in rat adipocytes.

PubMed

Mooney, R A; Bordwell, K L

1992-07-15

A permeabilized rat adipocyte model was developed which permitted an examination of: 1) insulin receptor autophosphorylation, 2) phosphorylation of a putative insulin receptor substrate of 160 kDa, pp160, and 3) the dephosphorylation reactions associated with each of these phosphoproteins. Rat adipocytes, preincubated with [32P]orthophosphate for 2 h, were exposed to insulin (10(-7) M) at the time of digitonin permeabilization. Phosphorylation of pp160 and autophosphorylation of the insulin receptor increased as a function of Mn2+ concentration in the media with near maximum responses at 10 mM. Maximum response was at least as large as the intact cell response to 10(-7) M insulin. In contrast, magnesium did not increase phosphorylation of pp160 although an increase in receptor autophosphorylation was observed. Autophosphorylation was preserved at digitonin concentrations of 20-100 micrograms/ml, but pp160 phosphorylation was negligible beyond 40 micrograms/ml. Our previous work demonstrated that the insulin receptor was associated with a phosphotyrosine phosphatase activity in permeabilized adipocytes (Mooney, R., and Anderson, D. (1989) J. Biol. Chem. 264, 6850-6857). The current permeabilized adipocyte model made possible an examination of the effects of phosphotyrosine phosphatase inhibitors, including several divalent metal cations (Zn2+, Co2+, and Ni2+), vanadate, and molybdate on both net phosphorylation of pp160 and autophosphorylation of the insulin receptor. Zn2+ at 100 microM, Ni2+ at 1 mM, and Co2+ at 1 or 5 mM increased insulin-dependent phosphorylation of pp160 at least 5-fold and autophosphorylation 2-fold. At higher concentrations of Zn2+ (1 mM) and Ni2+ (5 mM), however, no increase in phosphorylation of pp160 was observed and autophosphorylation was inhibited. Vanadate (1 mM) and molybdate (100 microM) increased insulin-dependent phosphorylation of pp160 by 3-fold when tested separately and 7-fold in combination. Insulin receptor autophosphorylation was increased 50% by each and 3-fold when the agents were combined. Dephosphorylation of pp160 and the insulin receptor was analyzed directly by permeabilizing prelabeled insulin-treated adipocytes in the presence of EDTA (10 mM). Dephosphorylation of pp160 was especially rapid with a t1/2 of approximately 10 s. The t1/2 for the insulin receptor was 37 s. Zn2+ at 1 mM (a concentration that inhibited the insulin receptor kinase) was a strong inhibitor of dephosphorylation, prolonging the rate of pp160 dephosphorylation more than 12-fold and insulin receptor dephosphorylation 3-fold.(ABSTRACT TRUNCATED AT 400 WORDS)

The Human Adenovirus Type 5 E4orf4 Protein Targets Two Phosphatase Regulators of the Hippo Signaling Pathway

PubMed Central

Mui, Melissa Z.; Zhou, Yiwang; Blanchette, Paola; Chughtai, Naila; Knight, Jennifer F.; Gruosso, Tina; Papadakis, Andreas I.; Huang, Sidong; Park, Morag; Gingras, Anne-Claude

2015-01-01

ABSTRACT When expressed alone at high levels, the human adenovirus E4orf4 protein exhibits tumor cell-specific p53-independent toxicity. A major E4orf4 target is the B55 class of PP2A regulatory subunits, and we have shown recently that binding of E4orf4 inhibits PP2AB55 phosphatase activity in a dose-dependent fashion by preventing access of substrates (M. Z. Mui et al., PLoS Pathog 9:e1003742, 2013, http://dx.doi.org/10.1371/journal.ppat.1003742). While interaction with B55 subunits is essential for toxicity, E4orf4 mutants exist that, despite binding B55 at high levels, are defective in cell killing, suggesting that other essential targets exist. In an attempt to identify additional targets, we undertook a proteomics approach to characterize E4orf4-interacting proteins. Our findings indicated that, in addition to PP2AB55 subunits, ASPP-PP1 complex subunits were found among the major E4orf4-binding species. Both the PP2A and ASPP-PP1 phosphatases are known to positively regulate effectors of the Hippo signaling pathway, which controls the expression of cell growth/survival genes by dephosphorylating the YAP transcriptional coactivator. We find here that expression of E4orf4 results in hyperphosphorylation of YAP, suggesting that Hippo signaling is affected by E4orf4 interactions with PP2AB55 and/or ASPP-PP1 phosphatases. Furthermore, knockdown of YAP1 expression was seen to enhance E4orf4 killing, again consistent with a link between E4orf4 toxicity and inhibition of the Hippo pathway. This effect may in fact contribute to the cancer cell specificity of E4orf4 toxicity, as many human cancer cells rely heavily on the Hippo pathway for their enhanced proliferation. IMPORTANCE The human adenovirus E4orf4 protein has been known for some time to induce tumor cell-specific death when expressed at high levels; thus, knowledge of its mode of action could be of importance for development of new cancer therapies. Although the B55 form of the phosphatase PP2A has long been known as an essential E4orf4 target, genetic analyses indicated that others must exist. To identify additional E4orf4 targets, we performed, for the first time, a large-scale affinity purification/mass spectrometry analysis of E4orf4 binding partners. Several additional candidates were detected, including key regulators of the Hippo signaling pathway, which enhances cell viability in many cancers, and results of preliminary studies suggested a link between inhibition of Hippo signaling and E4orf4 toxicity. PMID:26085163

Structure of a Protein Phosphatase 2A Holoenzyme: Insights into B55-Mediated Tau Dephosphorylation

PubMed Central

Xu, Yanhui; Chen, Yu; Zhang, Ping; Jeffrey, Philip D.; Shi, Yigong

2009-01-01

Summary Protein phosphatase 2A (PP2A) regulates many essential aspects of cellular physiology. Members of the regulatory B/B55/PR55 family are thought to play a key role in the dephosphorylation of Tau, whose hyperphosphorylation contributes to Alzheimer's disease. The underlying mechanisms of the PP2A-Tau connection remain largely enigmatic. Here, we report the complete reconstitution of a Tau dephosphorylation assay and the crystal structure of a heterotrimeric PP2A holoenzyme involving the regulatory subunit Bα. We show that Bα specifically and markedly facilitates dephosphorylation of the phosphorylated Tau in our reconstituted assay. The Bα subunit comprises a seven-bladed β propeller, with an acidic, substrate-binding groove located in the center of the propeller. The β propeller latches onto the ridge of the PP2A scaffold subunit with the help of a protruding β hairpin arm. Structure-guided mutagenesis studies revealed the underpinnings of PP2A-mediated dephosphorylation of Tau. PMID:18922469

Protein Phosphatase 2A Antagonizes ATM and ATR in a Cdk2- and Cdc7-Independent DNA Damage Checkpoint

PubMed Central

Petersen, Paris; Chou, Danny M.; You, Zhongsheng; Hunter, Tony; Walter, Johannes C.; Walter, Gernot

2006-01-01

We previously used a soluble cell-free system derived from Xenopus eggs to investigate the role of protein phosphatase 2A (PP2A) in chromosomal DNA replication. We found that immunodepletion of PP2A or inhibition of PP2A by okadaic acid (OA) inhibits initiation of DNA replication by preventing loading of the initiation factor Cdc45 onto prereplication complexes. Evidence was provided that PP2A counteracts an inhibitory protein kinase that phosphorylates and inactivates a crucial Cdc45 loading factor. Here, we report that the inhibitory effect of OA is abolished by caffeine, an inhibitor of the checkpoint kinases ataxia-telangiectasia mutated protein (ATM) and ataxia-telangiectasia related protein (ATR) but not by depletion of ATM or ATR from the extract. Furthermore, we demonstrate that double-strand DNA breaks (DSBs) cause inhibition of Cdc45 loading and initiation of DNA replication and that caffeine, as well as immunodepletion of either ATM or ATR, abolishes this inhibition. Importantly, the DSB-induced inhibition of Cdc45 loading is prevented by addition of the catalytic subunit of PP2A to the extract. These data suggest that DSBs and OA prevent Cdc45 loading through different pathways, both of which involve PP2A, but only the DSB-induced checkpoint implicates ATM and ATR. The inhibitory effect of DSBs on Cdc45 loading does not result from downregulation of cyclin-dependent kinase 2 (Cdk2) or Cdc7 activity and is independent of Chk2. However, it is partially dependent on Chk1, which becomes phosphorylated in response to DSBs. These data suggest that PP2A counteracts ATM and ATR in a DNA damage checkpoint in Xenopus egg extracts. PMID:16479016

An assessment of discriminatory power of office blood pressure measurements in predicting optimal ambulatory blood pressure control in people with type 2 diabetes.

PubMed

Kengne, Andre Pascal; Libend, Christelle Nong; Dzudie, Anastase; Menanga, Alain; Dehayem, Mesmin Yefou; Kingue, Samuel; Sobngwi, Eugene

2014-01-01

Ambulatory blood pressure (BP) measurements (ABPM) predict health outcomes better than office BP, and are recommended for assessing BP control, particularly in high-risk patients. We assessed the performance of office BP in predicting optimal ambulatory BP control in sub-Saharan Africans with type 2 diabetes (T2DM). Participants were a random sample of 51 T2DM patients (25 men) drug-treated for hypertension, receiving care in a referral diabetes clinic in Yaounde, Cameroon. A quality control group included 46 non-diabetic individuals with hypertension. Targets for BP control were systolic (and diastolic) BP. Mean age of diabetic participants was 60 years (standard deviation: 10) and median duration of diabetes was 6 years (min-max: 0-29). Correlation coefficients between each office-based variable and the 24-h ABPM equivalent (diabetic vs. non-diabetic participants) were 0.571 and 0.601 for systolic (SBP), 0.520 and 0.539 for diastolic (DBP), 0.631 and 0.549 for pulse pressure (PP), and 0.522 and 0.583 for mean arterial pressure (MAP). The c-statistic for the prediction of optimal ambulatory control from office-BP in diabetic participants was 0.717 for SBP, 0.494 for DBP, 0.712 for PP, 0.582 for MAP, and 0.721 for either SBP + DBP or PP + MAP. Equivalents in diabetes-free participants were 0.805, 0.763, 0.695, 0.801 and 0.813. Office DBP was ineffective in discriminating optimal ambulatory BP control in diabetic patients, and did not improve predictions based on office SBP alone. Targeting ABPM to those T2DM patients who are already at optimal office-based SBP would likely be more cost effective in this setting.

Nitric oxide leads to cytoskeletal reorganization in the retinal pigment epithelium under oxidative stress.

PubMed

Sripathi, Srinivas R; He, Weilue; Um, Ji-Yeon; Moser, Trevor; Dehnbostel, Stevie; Kindt, Kimberly; Goldman, Jeremy; Frost, Megan C; Jahng, Wan Jin

2012-01-01

Light is a risk factor for various eye diseases, including age-related macular degeneration (AMD) and retinitis pigmentosa (RP). We aim to understand how cytoskeletal proteins in the retinal pigment epithetlium (RPE) respond to oxidative stress, including light and how these responses affect apoptotic signaling. Previously, proteomic analysis revealed that the expression levels of vimentin and serine/threonine protein phosphatase 2A (PP2A) are significantly increased when mice are exposed under continuous light for 7 days compared to a condition of 12 hrs light/dark cycling exposure using retina degeneration 1 (rd1) model. When melatonin is administered to animals while they are exposed to continuous light, the levels of vimentin and PP2A return to a normal level. Vimentin is a substrate of PP2A that directly binds to vimentin and dephosphorylates it. The current study shows that upregulation of PP2Ac (catalytic subunit) phosphorylation negatively correlates with vimentin phosphorylation under stress condition. Stabilization of vimentin appears to be achieved by decreased PP2Ac phosphorylation by nitric oxide induction. We tested our hypothesis that site-specific modifications of PP2Ac may drive cytoskeletal reorganization by vimentin dephosphorylation through nitric oxide signaling. We speculate that nitric oxide determines protein nitration under stress conditions. Our results demonstrate that PP2A and vimentin are modulated by nitric oxide as a key element involved in cytoskeletal signaling. The current study suggests that external stress enhances nitric oxide to regulate PP2Ac and vimentin phosphorylation, thereby stabilizing or destabilizing vimentin. Phosphorylation may result in depolymerization of vimentin, leading to nonfilamentous particle formation. We propose that a stabilized vimentin might act as an anti-apoptotic molecule when cells are under oxidative stress.

Nitric oxide leads to cytoskeletal reorganization in the retinal pigment epithelium under oxidative stress

PubMed Central

Um, Ji-Yeon; Moser, Trevor; Dehnbostel, Stevie; Kindt, Kimberly; Goldman, Jeremy; Frost, Megan C.; Jahng, Wan Jin

2016-01-01

Light is a risk factor for various eye diseases, including age-related macular degeneration (AMD) and retinitis pigmentosa (RP). We aim to understand how cytoskeletal proteins in the retinal pigment epithetlium (RPE) respond to oxidative stress, including light and how these responses affect apoptotic signaling. Previously, proteomic analysis revealed that the expression levels of vimentin and serine/threonine protein phosphatase 2A (PP2A) are significantly increased when mice are exposed under continuous light for 7 days compared to a condition of 12 hrs light/dark cycling exposure using retina degeneration 1 (rd1) model. When melatonin is administered to animals while they are exposed to continuous light, the levels of vimentin and PP2A return to a normal level. Vimentin is a substrate of PP2A that directly binds to vimentin and dephosphorylates it. The current study shows that upregulation of PP2Ac (catalytic subunit) phosphorylation negatively correlates with vimentin phosphorylation under stress condition. Stabilization of vimentin appears to be achieved by decreased PP2Ac phosphorylation by nitric oxide induction. We tested our hypothesis that site-specific modifications of PP2Ac may drive cytoskeletal reorganization by vimentin dephosphorylation through nitric oxide signaling. We speculate that nitric oxide determines protein nitration under stress conditions. Our results demonstrate that PP2A and vimentin are modulated by nitric oxide as a key element involved in cytoskeletal signaling. The current study suggests that external stress enhances nitric oxide to regulate PP2Ac and vimentin phosphorylation, thereby stabilizing or destabilizing vimentin. Phosphorylation may result in depolymerization of vimentin, leading to nonfilamentous particle formation. We propose that a stabilized vimentin might act as an anti-apoptotic molecule when cells are under oxidative stress. PMID:27974994

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

Argondizzo, Adam; Cui, Xuefeng; Wang, Cong

We investigate the spectroscopy and photoinduced electron dynamics within the conduction band of reduced rutile TiO2(110) surface by multiphoton photoemission (mPP) spectroscopy with wavelength tunable ultrafast (!20 fs) laser pulse excitation. Tuning the mPP photon excitation energy between 2.9 and 4.6 eV reveals a nearly degenerate pair of new unoccupied states located at 2.73 ± 0.05 and 2.85 ± 0.05 eV above the Fermi level, which can be analyzed through the polarization and sample azimuthal orientation dependence of the mPP spectra. Based on the calculated electronic structure and optical transition moments, as well as related spectroscopic evidence, we assign thesemore » resonances to transitions between Ti 3d bands of nominally t2g and eg symmetry, which are split by crystal field. The initial states for the optical transition are the reduced Ti3+ states of t2g symmetry populated by formation oxygen vacancy defects, which exist within the band gap of TiO2. Furthermore,we studied the electron dynamics within the conduction band of TiO2 by three-dimensional time-resolved pump-probe interferometric mPP measurements. The spectroscopic and time-resolved studies reveal competition between 2PP and 3PP processes where the t2g-eg transitions in the 2PP process saturate, and are overtaken by the 3PP process initiated by the band-gap excitation from the valence band of TiO2.« less

Proposal of Mucilaginibacter galii sp. nov. isolated from leaves of Galium album.

PubMed

Aydogan, Ebru L; Busse, Hans-Jürgen; Moser, Gerald; Müller, Christoph; Kämpfer, Peter; Glaeser, Stefanie P

2017-05-01

A pale-pink-pigmented, Gram-stain-negative, rod-shaped, non-spore-forming bacterial strain, PP-F2F-G47T, was isolated from the phyllosphere of the herbaceous plant Galium album. Phylogenetic analysis based on the nearly full-length 16S rRNA gene sequence revealed highest sequence similarity to the type strains of Mucilaginibacter daejeonensis (96.2 %), Mucilaginibacter dorajii (95.7 %) and Mucilaginibacter phyllosphaerae (95.5 %). 16S rRNA gene sequence similarities to all other type strains were below 95.5 %. The predominant cellular fatty acids of the strain were C16 : 1ω7c/iso-C15 : 0 2-OH (measured as summed feature 3) and iso-C15 : 0. The major compound in the polyamine pattern was sym-homospermidine and major quinone was menaquinone MK-7. The polar lipid profile was composed of phosphatidylethanolamine and several unidentified aminolipipids, phospholipids, aminophospholipids and lipids without a functional group. A sphingophospholipid could not be detected but a ninhydrin-positive alkaline-stable lipid was visible. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid. Based on phylogenetic, chemotaxonomic and phenotypic analyses a novel species is proposed, Mucilaginibacter galii sp. nov., with PP-F2F-G47T (=CCM 8711T=CIP 111182T=LMG 29767T) as the type strain.

Influence of In Vitro and In Vivo Oxygen Modulation on β Cell Differentiation From Human Embryonic Stem Cells

PubMed Central

Cechin, Sirlene; Álvarez-Cubela, Silvia; Giraldo, Jaime A.; Molano, Ruth D.; Villate, Susana; Ricordi, Camillo; Pileggi, Antonello; Inverardi, Luca

2014-01-01

The possibility of using human embryonic stem (hES) cell-derived β cells as an alternative to cadaveric islets for the treatment of type 1 diabetes is now widely acknowledged. However, current differentiation methods consistently fail to generate meaningful numbers of mature, functional β cells. In order to address this issue, we set out to explore the role of oxygen modulation in the maturation of pancreatic progenitor (PP) cells differentiated from hES cells. We have previously determined that oxygenation is a powerful driver of murine PP differentiation along the endocrine lineage of the pancreas. We hypothesized that targeting physiological oxygen partial pressure (pO2) levels seen in mature islets would help the differentiation of PP cells along the β-cell lineage. This hypothesis was tested both in vivo (by exposing PP-transplanted immunodeficient mice to a daily hyperbaric oxygen regimen) and in vitro (by allowing PP cells to mature in a perfluorocarbon-based culture device designed to carefully adjust pO2 to a desired range). Our results show that oxygen modulation does indeed contribute to enhanced maturation of PP cells, as evidenced by improved engraftment, segregation of α and β cells, body weight maintenance, and rate of diabetes reversal in vivo, and by elevated expression of pancreatic endocrine makers, β-cell differentiation yield, and insulin production in vitro. Our studies confirm the importance of oxygen modulation as a key variable to consider in the design of β-cell differentiation protocols and open the door to future strategies for the transplantation of fully mature β cells. PMID:24375542

Feedback Regulation of ABA Signaling and Biosynthesis by a bZIP Transcription Factor Targets Drought-Resistance-Related Genes1[OPEN

PubMed Central

Tang, Ning; Yang, Jun; Peng, Lei; Ma, Siqi; Xu, Yan; Li, Guoliang

2016-01-01

The OsbZIP23 transcription factor has been characterized for its essential role in drought resistance in rice (Oryza sativa), but the mechanism is unknown. In this study, we first investigated the transcriptional activation of OsbZIP23. A homolog of SnRK2 protein kinase (SAPK2) was found to interact with and phosphorylate OsbZIP23 for its transcriptional activation. SAPK2 also interacted with OsPP2C49, an ABI1 homolog, which deactivated the SAPK2 to inhibit the transcriptional activation activity of OsbZIP23. Next, we performed genome-wide identification of OsbZIP23 targets by immunoprecipitation sequencing and RNA sequencing analyses in the OsbZIP23-overexpression, osbzip23 mutant, and wild-type rice under normal and drought stress conditions. OsbZIP23 directly regulates a large number of reported genes that function in stress response, hormone signaling, and developmental processes. Among these targets, we found that OsbZIP23 could positively regulate OsPP2C49, and overexpression of OsPP2C49 in rice resulted in significantly decreased sensitivity of the abscisic acid (ABA) response and rapid dehydration. Moreover, OsNCED4 (9-cis-epoxycarotenoid dioxygenase4), a key gene in ABA biosynthesis, was also positively regulated by OsbZIP23. Together, our results suggest that OsbZIP23 acts as a central regulator in ABA signaling and biosynthesis, and drought resistance in rice. PMID:27325665

The C. elegans RSA complex localizes protein phosphatase 2A to centrosomes and regulates mitotic spindle assembly.

PubMed

Schlaitz, Anne-Lore; Srayko, Martin; Dammermann, Alexander; Quintin, Sophie; Wielsch, Natalie; MacLeod, Ian; de Robillard, Quentin; Zinke, Andrea; Yates, John R; Müller-Reichert, Thomas; Shevchenko, Andrei; Oegema, Karen; Hyman, Anthony A

2007-01-12

Microtubule behavior changes during the cell cycle and during spindle assembly. However, it remains unclear how these changes are regulated and coordinated. We describe a complex that targets the Protein Phosphatase 2A holoenzyme (PP2A) to centrosomes in C. elegans embryos. This complex includes Regulator of Spindle Assembly 1 (RSA-1), a targeting subunit for PP2A, and RSA-2, a protein that binds and recruits RSA-1 to centrosomes. In contrast to the multiple functions of the PP2A catalytic subunit, RSA-1 and RSA-2 are specifically required for microtubule outgrowth from centrosomes and for spindle assembly. The centrosomally localized RSA-PP2A complex mediates these functions in part by regulating two critical mitotic effectors: the microtubule destabilizer KLP-7 and the C. elegans regulator of spindle assembly TPXL-1. By regulating a subset of PP2A functions at the centrosome, the RSA complex could therefore provide a means of coordinating microtubule outgrowth from centrosomes and kinetochore microtubule stability during mitotic spindle assembly.

Branching fractions for {chi}{sub cJ{yields}}pp{pi}{sup 0}, pp{eta}, and pp{omega}

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

Onyisi, P. U. E.; Rosner, J. L.; Alexander, J. P.

2010-07-01

Using a sample of 25.9x10{sup 6} {psi}(2S) decays acquired with the CLEO-c detector at the CESR e{sup +}e{sup -} collider, we report branching fractions for the decays {chi}{sub cJ{yields}}pp{pi}{sup 0}, pp{eta}, and pp{omega}, with J=0, 1, 2. Our results for B({chi}{sub cJ{yields}}pp{pi}{sup 0}) and B({chi}{sub cJ{yields}}pp{eta}) are consistent with, but more precise than, previous measurements. Furthermore, we include the first measurement of B({chi}{sub cJ{yields}}pp{omega}).

Characterization of 9H-(1,3-dichlor-9, 9-dimethylacridin-2-ona-7-yl)-phosphate (DDAO) as substrate of PP-2A in a fluorimetric microplate assay for diarrhetic shellfish toxins (DSP).

PubMed

Leira, F; Vieites, J M; Vieytes, M R; Botana, L M

2000-12-01

Specific inhibition of protein-phosphatases by diarrhetic shellfish toxins (DSP) of the okadaic acid group, has led to the development of a fluorescent enzyme inhibition assay for these toxins using protein-phosphatase 2A (PP-2A) and fluorogenic substrates of the enzyme. Two different substrates of PP-2A have been previously used in this microplate assay: 4-methylumbelliferyl phosphate and fluorescein diphosphate (FDP). In this report, we present the results obtained using a new fluorogenic substrate of PP-2A, the compound dimethylacridinone phosphate (DDAO). A linear relationship between PP-2A concentration and DDAO-induced fluorescence was observed. Okadaic acid (0.0157-9.43 nM)-dependent inhibition of phosphatase activity showed similar results using FDP and DDAO. Recovery percentages obtained with FDP and DDAO in spiked mussel samples (both raw and canned) were very similar and reproducible. Comparative analysis of DSP-contaminated mussel samples by HPLC and FDP/DDAO-PP-2A showed a good correlation among all methods, thus demonstrating that DDAO can be used as a fluorogenic substrate to quantify okadaic acid and related toxins in bivalve molluscs with optimum reliability.

The Curves Exercise Suppresses Endotoxemia in Korean Women with Obesity.

PubMed

Jin, Seon Ah; Kim, Sun Kyeong; Seo, Hee Jung; Kim, Mijoo; Ahn, Kye Taek; Kim, Jun Hyung; Park, Jae Hyeong; Lee, Jae Hwan; Choi, Si Wan; Jeong, Jin Ok

2017-02-01

Obesity and metabolic syndrome is a worldwide pandemic and associated with high cardiovascular risk. Metabolic endotoxemia (ME) is thought to be an underlying molecular mechanism. It triggers toll-like receptor 4-mediated inflammatory adipokines and causes a chronic low grade inflammatory status, which results in cardiovascular risk increase. Exercise is the best nonpharmacological treatment to improve prognosis. In this study, we examined the circulating endotoxin level in Korean obese women and investigated effects of exercise on it. Women over body mass index (BMI) 25 kg/m² participated in a resistance training exercise, Curves. At baseline and after 12 weeks exercise, tests including blood samples were taken. In Korean obese women, the fasting endotoxin was 1.45 ± 0.11 EU/mL. Ingestion of a high calorie meal led to a peak level after 2 hours (postprandial 2 hours [PP2]) and a significant rise over the 4 hours (postprandial 4 hours [PP4]) in it (1.78 ± 0.15 and 1.75 ± 0.14 EU/mL for PP2 and PP4, P < 0.05 vs. fasting). After exercise, BMI and hip circumference were reduced significantly. The total cholesterol (TC) at fasting, PP2 and PP4 were decreased significantly. All levels of circulating endotoxin at fasting, PP2 and PP4 showed reduction. But, the peak change was only significant (baseline vs. 12 weeks for PP2; 1.78 ± 0.15 vs. 1.48 ± 0.06 EU/mL, P < 0.05). We report the circulating endotoxin level in Korean obese women for the first time. Also, we establish that energy intake leads to endotoxemia and exercise suppresses the peak endotoxemia after meal. It suggests an impact for a better prognosis in obese women who follow regular exercise.

Selective Proteasomal Degradation of the B′β Subunit of Protein Phosphatase 2A by the E3 Ubiquitin Ligase Adaptor Kelch-like 15*

PubMed Central

Oberg, Elizabeth A.; Nifoussi, Shanna K.; Gingras, Anne-Claude; Strack, Stefan

2012-01-01

Protein phosphatase 2A (PP2A), a ubiquitous and pleiotropic regulator of intracellular signaling, is composed of a core dimer (AC) bound to a variable (B) regulatory subunit. PP2A is an enzyme family of dozens of heterotrimers with different subcellular locations and cellular substrates dictated by the B subunit. B′β is a brain-specific PP2A regulatory subunit that mediates dephosphorylation of Ca2+/calmodulin-dependent protein kinase II and tyrosine hydroxylase. Unbiased proteomic screens for B′β interactors identified Cullin3 (Cul3), a scaffolding component of E3 ubiquitin ligase complexes, and the previously uncharacterized Kelch-like 15 (KLHL15). KLHL15 is one of ∼40 Kelch-like proteins, many of which have been identified as adaptors for the recruitment of substrates to Cul3-based E3 ubiquitin ligases. Here, we report that KLHL15-Cul3 specifically targets B′β to promote turnover of the PP2A subunit by ubiquitylation and proteasomal degradation. Comparison of KLHL15 and B′β tissue expression profiles suggests that the E3 ligase adaptor contributes to selective expression of the PP2A/B′β holoenzyme in the brain. We mapped KLHL15 residues critical for homodimerization as well as interaction with Cul3 and B′β. Explaining PP2A subunit selectivity, the divergent N terminus of B′β was found necessary and sufficient for KLHL15-mediated degradation, with Tyr-52 having an obligatory role. Although KLHL15 can interact with the PP2A/B′β heterotrimer, it only degrades B′β, thus promoting exchange with other regulatory subunits. E3 ligase adaptor-mediated control of PP2A holoenzyme composition thereby adds another layer of regulation to cellular dephosphorylation events. PMID:23135275

Development and application of a non-targeted extraction method for the analysis of migrating compounds from plastic baby bottles by GC-MS.

PubMed

Onghena, Matthias; van Hoeck, Els; Vervliet, Philippe; Scippo, Marie Louise; Simon, Coraline; van Loco, Joris; Covaci, Adrian

2014-01-01

In 2011, the European Union prohibited the production of polycarbonate (PC) baby bottles due to the toxic effects of the PC monomer bisphenol-A. Therefore, baby bottles made of alternative materials, e.g. polypropylene (PP) or polyethersulphone (PES), are currently marketed. The principal aim of the study was the identification of major compounds migrating from baby bottles using a liquid-liquid extraction followed by GC/MS analysis. A 50% EtOH in water solution was selected as a simulant for milk. After sterilisation of the bottle, three migration experiments were performed during 2 h at 70°C. A non-targeted liquid-liquid extraction with ethyl acetate-n-hexane (1:1) was performed on the simulant samples. Identification of migrants from 24 baby bottles was done using commercially available WILEY and NIST mass spectra libraries. Differences in the migrating compounds and their intensities were observed between the different types of plastics, but also between the same polymer from a different producer. Differences in the migration patterns were perceived as well between the sterilisation and the migrations and within the different migrations. Silicone, Tritan™ and PP exhibited a wide variety of migrating compounds, whereas PES and polyamide (PA) showed a lower amount of migrants, though sometimes in relatively large concentrations (azacyclotridecan-2-one up to 250 µg kg⁻¹). Alkanes (especially in PP bottles), phthalates (dibutylphthalate in one PP bottle (±40 µg kg⁻¹) and one silicone bottle (±25 µg kg⁻¹); diisobutylphthalate in one PP (±10 µg kg⁻¹), silicone (up to ±80 µg kg⁻¹); and Tritan™ bottle (±30 µg kg⁻¹)), antioxidants (Irgafos 168, degradation products of Irganox 1010 and Irganox 1076), etc. were detected for PP, silicone and Tritan™ bottles. Although the concentrations were relatively low, some compounds not authorised by European Union Regulation No. 10/2011, such as 2,4-di-tert-butylphenol (10-100 µg kg⁻¹) or 2-butoxyethyl acetate (about 300 µg kg⁻¹) were detected. Migrating chemicals were identified as confirmed (using a standard) or as tentative (further confirmation required).

A novel mitochondrial matrix serine/threonine protein phosphatase regulates the mitochondria permeability transition pore and is essential for cellular survival and development

PubMed Central

Lu, Gang; Ren, Shuxun; Korge, Paavo; Choi, Jayoung; Dong, Yuan; Weiss, James; Koehler, Carla; Chen, Jau-nian; Wang, Yibin

2007-01-01

Mitochondria play a central role in the regulation of programmed cell death signaling. Here, we report the finding of a mitochondrial matrix-targeted protein phosphatase 2C family member (PP2Cm) that regulates mitochondrial membrane permeability transition pore (MPTP) opening and is essential for cell survival, embryonic development, and cardiac function. PP2Cm is highly conserved among vertebrates, with the highest expression levels detected in the heart and brain. Small hairpin RNA (shRNA)-mediated knockdown of PP2Cm resulted in cell death associated with loss of mitochondrial membrane potential in cultured cardiac mycoytes and an induction of hepatocyte apoptosis in vivo. PP2Cm-deficient mitochondria showed elevated susceptibility to calcium-induced MPTP opening, whereas mitochondrial oxidative phosphorylation activities were not affected. Finally, inactivation of PP2Cm in developing zebrafish embryos caused abnormal cardiac and neural development as well as heart failure associated with induced apoptosis. These data suggest that PP2Cm is a novel mitochondrial protein phosphatase that has a critical function in cell death and survival, and may play a role in regulating the MPTP opening. PMID:17374715

Monitoring autophagic flux using p62/SQSTM1 based luciferase reporters in glioma cells.

PubMed

Min, Zhang; Ting, Yao; Mingtao, Gong; Xiaofei, Tang; Dong, Yan; Chenguang, Zhang; Wei, Ding

2018-02-01

Autophagy is a highly dynamic process characterized with the term of autophagic flux. In the present study, we developed a quantifiable luciferase reporter system to measure the capacity as well as the dynamics of autophagic flux. Briefly, a luciferase variant of Luc2p was fused with p62/SQSTM1 or its UBA domain deletion mutant (p62ΔU) and transfected into cells. The expressed Luc2p-p62 fusion protein was primarily degraded via autophagy, while Luc2p-p62ΔU was employed as a normalization control due to its resistance to autophagic degradation. The luciferase activity of the lysates from two parallel populations of glioma cells expressing either Luc2p-p62 or Luc2p-p62ΔU was determined and the ratio of Luc2p-p62ΔU/Luc2p-p62 was used to assay the autophagic flux. By this approach, the induction of autophagy was manifested as an increased Luc2p-p62ΔU/Luc2p-p62 ratio, which could be neutralized by autophagy inhibitors or knockdown of ATG5. The performance of our autophagic flux detection system was comparable to a recently reported GFP-LC3-RFP-LC3ΔG probe. We tested the system in TMZ treated glioma cells, and found that coadministration of chloroquine to attenuate cellular autophagic flux significantly improved the TMZ efficacy by triggering more early apoptosis. Collectively, our luciferase-based autophagic flux assay may serve as a useful alternative yet sensitive method for autophagic flux detection in tumor cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Oxidative impairment of hippocampal long-term potentiation involves activation of protein phosphatase 2A and is prevented by ketone bodies.

PubMed

Maalouf, Marwan; Rho, Jong M

2008-11-15

Previous studies have shown that ketone bodies (KB) exert antioxidant effects in experimental models of neurological disease. In the present study, we explored the effects of the KB acetoacetate (ACA) and beta-hydroxybutyrate (BHB) on impairment of hippocampal long-term potentiation (LTP) in rats by hydrogen peroxide (H(2)O(2)) using electrophysiological, fluorescence imaging, and enzyme assay techniques. We found that: 1) a combination of ACA and BHB (1 mM each) prevented impairment of LTP by H(2)O(2) (200 microM); 2) KB significantly lowered intracellular levels of reactive oxygen species (ROS)--measured with the fluorescent indicator carboxy-H(2)DCFDA (carboxy-2',7'-dichlorodihydrofluorescein diacetate)--in CA1 pyramidal neurons exposed to H(2)O(2); 3) the effect of KB on LTP was replicated by the protein phosphatase 2A (PP2A) inhibitor fostriecin; 4) KB prevented impairment of LTP by the PP2A activator C(6) ceramide; 5) fostriecin did not prevent the increase in ROS levels in CA1 pyramidal neurons exposed to H(2)O(2), and C(6) ceramide did not increase ROS levels; 6) PP2A activity was enhanced by both H(2)O(2) and rotenone (a mitochondrial complex I inhibitor that increases endogenous superoxide production); and 7) KB inhibited PP2A activity in protein extracts from brain tissue treated with either H(2)O(2) or ceramide. We propose that oxidative impairment of hippocampal LTP is associated with PP2A activation, and that KB prevent this impairment in part by inducing PP2A inhibition through an antioxidant mechanism.

Effect of supplemental oxygen versus dobutamine administration on liver oxygen tension in dPP-guided normovolemic pigs.

PubMed

Pestel, G; Fukui, K; Hager, H; Kurz, A; Hiltebrand, L

2009-01-01

Difference in pulse pressure (dPP) confirms adequate intravascular filling as a prerequisite for tissue perfusion. We hypothesized that both oxygen and dobutamine increase liver tissue oxygen tension (ptO(2)). Eight anesthetized pigs received dPP-guided fluid management. Hepatic pO(2) was measured with Clark-type electrodes placed subcapsularly, and on the liver surface. Pigs received: (1) supplemental oxygen (F(i)O(2) 1.0); (2) dobutamine 2.5 microg/kg/min, and (3) dobutamine 5 microg/kg/min. Data were analyzed using repeated-measures ANOVA followed by a Tukey post-test for multiple comparisons. ptO(2 )measured subcapsularly and at the liver surface were compared using the Bland-Altman plot. Variation in F(i)O(2) changed local hepatic tissue ptO(2) [subcapsular measurement: 39 +/- 12 (F(i)O(2) 0.3), 89 +/- 35 mm Hg (F(i)O(2) 1.0, p = 0.01 vs. F(i)O(2) 0.3), 44 +/- 10 mm Hg (F(i)O(2) 0.3, p = 0.05 vs. F(i)O(2) 1.0); surface measurement: 52 +/- 35 (F(i)O(2) 0.3), 112 +/- 24 mm Hg (F(i)O(2) 1.0, p = 0.001 vs. F(i)O(2) 0.3), 54 +/- 24 mm Hg (F(i)O(2) 0.3, p = 0.001 vs. F(i)O(2) 1.0)]. Surface measurements were widely scattered compared to subcapsular measurements (bias: -15 mm Hg, precision: 76.3 mm Hg). Dobutamine did not affect hepatic oxygenation. Supplemental oxygen increased hepatic tissue pO(2) while dobutamine did not. Although less invasive, the use of surface measurements is discouraged. Copyright 2009 S. Karger AG, Basel.

Adaptation of HepG2 cells to a steady-state reduction in the content of protein phosphatase 6 (PP6) catalytic subunit

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

Boylan, Joan M.; Salomon, Arthur R.; Department of Chemistry, Brown University, Providence, RI

Protein phosphatase 6 (PP6) is a ubiquitous Ser/Thr phosphatase involved in an array of cellular processes. To assess the potential of PP6 as a therapeutic target in liver disorders, we attenuated expression of the PP6 catalytic subunit in HepG2 cells using lentiviral-transduced shRNA. Two PP6 knock-down (PP6KD) cell lines (90% reduction of PP6-C protein content) were studied in depth. Both proliferated at a rate similar to control cells. However, flow cytometry indicated G2/M cell cycle arrest that was accounted for by a shift of the cells from a diploid to tetraploid state. PP6KD cells did not show an increase inmore » apoptosis, nor did they exhibit reduced viability in the presence of bleomycin or taxol. Gene expression analysis by microarray showed attenuated anti-inflammatory signaling. Genes associated with DNA replication were downregulated. Mass spectrometry-based phosphoproteomic analysis yielded 80 phosphopeptides representing 56 proteins that were significantly affected by a stable reduction in PP6-C. Proteins involved in DNA replication, DNA damage repair and pre-mRNA splicing were overrepresented among these. PP6KD cells showed intact mTOR signaling. Our studies demonstrated involvement of PP6 in a diverse set of biological pathways and an adaptive response that may limit the effectiveness of targeting PP6 in liver disorders. - Highlights: • Lentiviral-transduced shRNA was used to generate a stable knockdown of PP6 in HepG2 cells. • Cells adapted to reduced PP6; cell proliferation was unaffected, and cell survival was normal. • However, PP6 knockdown was associated with a transition to a tetraploid state. • Genomic profiling showed downregulated anti-inflammatory signaling and DNA replication. • Phosphoproteomic profiling showed changes in proteins associated with DNA replication and repair.« less

Isocaloric Diets High in Animal or Plant Protein Reduce Liver Fat and Inflammation in Individuals With Type 2 Diabetes.

PubMed

Markova, Mariya; Pivovarova, Olga; Hornemann, Silke; Sucher, Stephanie; Frahnow, Turid; Wegner, Katrin; Machann, Jürgen; Petzke, Klaus Jürgen; Hierholzer, Johannes; Lichtinghagen, Ralf; Herder, Christian; Carstensen-Kirberg, Maren; Roden, Michael; Rudovich, Natalia; Klaus, Susanne; Thomann, Ralph; Schneeweiss, Rosemarie; Rohn, Sascha; Pfeiffer, Andreas F H

2017-02-01

Nonalcoholic fatty liver disease (NAFLD) is associated with increased risk of hepatic, cardiovascular, and metabolic diseases. High-protein diets, rich in methionine and branched chain amino acids (BCAAs), apparently reduce liver fat, but can induce insulin resistance. We investigated the effects of diets high in animal protein (AP) vs plant protein (PP), which differ in levels of methionine and BCAAs, in patients with type 2 diabetes and NAFLD. We examined levels of liver fat, lipogenic indices, markers of inflammation, serum levels of fibroblast growth factor 21 (FGF21), and activation of signaling pathways in adipose tissue. We performed a prospective study of individuals with type 2 diabetes and NAFLD at a tertiary medical center in Germany from June 2013 through March 2015. We analyzed data from 37 subjects placed on a diet high in AP (rich in meat and dairy foods; n = 18) or PP (mainly legume protein; n = 19) without calorie restriction for 6 weeks. The diets were isocaloric with the same macronutrient composition (30% protein, 40% carbohydrates, and 30% fat). Participants were examined at the start of the study and after the 6-week diet period for body mass index, body composition, hip circumference, resting energy expenditure, and respiratory quotient. Body fat and intrahepatic fat were detected by magnetic resonance imaging and spectroscopy, respectively. Levels of glucose, insulin, liver enzymes, and inflammation markers, as well as individual free fatty acids and free amino acids, were measured in collected blood samples. Hyperinsulinemic euglycemic clamps were performed to determine whole-body insulin sensitivity. Subcutaneous adipose tissue samples were collected and analyzed for gene expression patterns and phosphorylation of signaling proteins. Postprandial levels of BCAAs and methionine were significantly higher in subjects on the AP vs the PP diet. The AP and PP diets each reduced liver fat by 36%-48% within 6 weeks (for AP diet P = .0002; for PP diet P = .001). These reductions were unrelated to change in body weight, but correlated with down-regulation of lipolysis and lipogenic indices. Serum level of FGF21 decreased by 50% in each group (for AP diet P < .0002; for PP diet P < .0002); decrease in FGF21 correlated with loss of hepatic fat. In gene expression analyses of adipose tissue, expression of the FGF21 receptor cofactor β-klotho was associated with reduced expression of genes encoding lipolytic and lipogenic proteins. In patients on each diet, levels of hepatic enzymes and markers of inflammation decreased, insulin sensitivity increased, and serum level of keratin 18 decreased. In a prospective study of patients with type 2 diabetes, we found diets high in protein (either animal or plant) significantly reduced liver fat independently of body weight, and reduced markers of insulin resistance and hepatic necroinflammation. The diets appear to mediate these changes via lipolytic and lipogenic pathways in adipose tissue. Negative effects of BCAA or methionine were not detectable. FGF21 level appears to be a marker of metabolic improvement. ClinicalTrials.gov ID NCT02402985. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

CBe5Hn((n-4)) (n = 2-5): Hydrogen-Stabilized CBe5 Pentagons Containing Planar or Quasi-Planar Pentacoordinate Carbons.

PubMed

Guo, Jin-Chang; Ren, Guang-Ming; Miao, Chang-Qing; Tian, Wen-Juan; Wu, Yan-Bo; Wang, Xiaotai

2015-12-31

The diagonal relationship between beryllium and aluminum and the isoelectronic relationship between BeH unit and Al atom were utilized to design a new series ppC- or quasi-ppC-containing species C5v CBe5H5(+), Cs CBe5H4, C2v CBe5H3(-), and C2v CBe5H2(2-) by replacing the Al atoms in previously reported global minima planar pentacoordinate carbon (ppC) species D5h CAl5(+), C2v CAl4Be, C2v CAl3Be2(-), and C2v CAl2Be3(2-) with BeH units. The three-center two-electron (3c-2e) bonds formed between Be and bridging H atoms were crucial for the stabilization of these ppC species. The natural bond orbital (NBO) and adaptive natural density partitioning (AdNDP) analyses revealed that the central ppCs or quasi-ppCs possess the stable eight electron-shell structures. The AdNDP analyses also disclosed that these species are all 6σ+2π double-aromatic in nature. The aromaticity was proved by the calculated negative nucleus-independent chemical shifts (NICS) values. DFT and high-level CCSD(T) calculations revealed that these ppC- or quasi-ppC species are the global minimum or competitive low-lying local minimum (Cs CBe5H4) on their potential energy surfaces. The Born-Oppenheimer molecular dynamic (BOMD) simulations revealed that the H atoms in C2v CBe5H3(-) and C2v CBe5H2(2-) can easily rotate around the CBe5 cores and the structure of quasi-planar C5v CBe5H5(+) will become the planar structure at room temperature; however, these interesting dynamic behaviors did not indicate the kinetic instability as the basic ppC structures were maintained during the simulations. Therefore, it would be potentially possible to realize these interesting ppC- or quasi-ppc-species in future experiments.

The beta-arrestin pathway-selective type 1A angiotensin receptor (AT1A) agonist [Sar1,Ile4,Ile8]angiotensin II regulates a robust G protein-independent signaling network.

PubMed

Kendall, Ryan T; Strungs, Erik G; Rachidi, Saleh M; Lee, Mi-Hye; El-Shewy, Hesham M; Luttrell, Deirdre K; Janech, Michael G; Luttrell, Louis M

2011-06-03

The angiotensin II peptide analog [Sar(1),Ile(4),Ile(8)]AngII (SII) is a biased AT(1A) receptor agonist that stimulates receptor phosphorylation, β-arrestin recruitment, receptor internalization, and β-arrestin-dependent ERK1/2 activation without activating heterotrimeric G-proteins. To determine the scope of G-protein-independent AT(1A) receptor signaling, we performed a gel-based phosphoproteomic analysis of AngII and SII-induced signaling in HEK cells stably expressing AT(1A) receptors. A total of 34 differentially phosphorylated proteins were detected, of which 16 were unique to SII and eight to AngII stimulation. MALDI-TOF/TOF mass fingerprinting was employed to identify 24 SII-sensitive phosphoprotein spots, of which three (two peptide inhibitors of protein phosphatase 2A (I1PP2A and I2PP2A) and prostaglandin E synthase 3 (PGES3)) were selected for validation and further study. We found that phosphorylation of I2PP2A was associated with rapid and transient inhibition of a β-arrestin 2-associated pool of protein phosphatase 2A, leading to activation of Akt and increased phosphorylation of glycogen synthase kinase 3β in an arrestin signalsome complex. SII-stimulated PGES3 phosphorylation coincided with an increase in β-arrestin 1-associated PGES3 and an arrestin-dependent increase in cyclooxygenase 1-dependent prostaglandin E(2) synthesis. These findings suggest that AT(1A) receptors regulate a robust G protein-independent signaling network that affects protein phosphorylation and autocrine/paracrine prostaglandin production and that these pathways can be selectively modulated by biased ligands that antagonize G protein activation.

Parallelism Effects and Verb Activation: The Sustained Reactivation Hypothesis

PubMed Central

Shapiro, Lewis P.; Love, Tracy

2010-01-01

This study investigated the processes underlying parallelism by evaluating the activation of a parallel element (i.e., a verb) throughout and-coordinated sentences. Four points were tested: (1) approximately 1,600ms after the verb in the first conjunct (PP1), (2) immediately following the conjunction (PP2), (3) approximately 1,100ms after the conjunction (PP3), (4) at the end of the second conjunct (PP4). The results revealed no activation at PP1, suggesting activation related to the initial presentation had decayed by this point; however, activation was observed at PP2, PP3, and PP4, suggesting the conjunction elicits reactivation that is sustained throughout the second conjunct. These findings support a specific hypothesis about parallelism, the sustained reactivation hypothesis. This hypothesis claims that, in conjoined structures, a cue that is associated with parallelism elicits the reactivation of material from the first conjunct and that this activation is sustained until integration with the second conjunct can be completed. PMID:19774464

Parallelism effects and verb activation: the sustained reactivation hypothesis.

PubMed

Callahan, Sarah M; Shapiro, Lewis P; Love, Tracy

2010-04-01

This study investigated the processes underlying parallelism by evaluating the activation of a parallel element (i.e., a verb) throughout and-coordinated sentences. Four points were tested: (1) approximately 1,600 ms after the verb in the first conjunct (PP1), (2) immediately following the conjunction (PP2), (3) approximately 1,100 ms after the conjunction (PP3), (4) at the end of the second conjunct (PP4). The results revealed no activation at PP1, suggesting activation related to the initial presentation had decayed by this point; however, activation was observed at PP2, PP3, and PP4, suggesting the conjunction elicits reactivation that is sustained throughout the second conjunct. These findings support a specific hypothesis about parallelism, the sustained reactivation hypothesis. This hypothesis claims that, in conjoined structures, a cue that is associated with parallelism elicits the reactivation of material from the first conjunct and that this activation is sustained until integration with the second conjunct can be completed.

Overlapping functions of bone sialoprotein and pyrophosphate regulators in directing cementogenesis.

PubMed

Ao, M; Chavez, M B; Chu, E Y; Hemstreet, K C; Yin, Y; Yadav, M C; Millán, J L; Fisher, L W; Goldberg, H A; Somerman, M J; Foster, B L

2017-12-01

Although acellular cementum is essential for tooth attachment, factors directing its development and regeneration remain poorly understood. Inorganic pyrophosphate (PP i ), a mineralization inhibitor, is a key regulator of cementum formation: tissue-nonspecific alkaline phosphatase (Alpl/TNAP) null mice (increased PP i ) feature deficient cementum, while progressive ankylosis protein (Ank/ANK) null mice (decreased PP i ) feature increased cementum. Bone sialoprotein (Bsp/BSP) and osteopontin (Spp1/OPN) are multifunctional extracellular matrix components of cementum proposed to have direct and indirect effects on cell activities and mineralization. Studies on dentoalveolar development of Bsp knockout (Bsp -/- ) mice revealed severely reduced acellular cementum, however underlying mechanisms remain unclear. The similarity in defective cementum phenotypes between Bsp -/- mice and Alpl -/- mice (the latter featuring elevated PP i and OPN), prompted us to examine whether BSP is operating by modulating PP i -associated genes. Genetic ablation of Bsp caused a 2-fold increase in circulating PP i , altered mRNA expression of Alpl, Spp1, and Ank, and increased OPN protein in the periodontia. Generation of a Bsp knock-out (KO) cementoblast cell line revealed significantly decreased mineralization capacity, 50% increased PP i in culture media, and increased Spp1 and Ank mRNA expression. While addition of 2μg/ml recombinant BSP altered Spp1, Ank, and Enpp1 expression in cementoblasts, changes resulting from this dose were not dependent on the integrin-binding RGD motif or MAPK/ERK signaling pathway. Decreasing PP i by genetic ablation of Ank on the Bsp -/- mouse background reestablished cementum formation, allowing >3-fold increased acellular cementum volume compared to wild-type (WT). However, deleting Ank did not fully compensate for the absence of BSP. Bsp -/- ; Ank -/- double-deficient mice exhibited mean 20-27% reduced cementum thickness and volume compared to Ank -/- mice. From these data, we conclude that the perturbations in PP i metabolism are not solely driving the cementum pathology in Bsp -/- mice, and that PP i is more potent than BSP as a cementum regulator, as shown by the ability to override loss of BSP by lowering PP i . We propose that BSP and PP i work in concert to direct mineralization in cementum and likely other mineralized tissues. Copyright © 2017 Elsevier Inc. All rights reserved.

Diversity in Guanosine 3′,5′-Bisdiphosphate (ppGpp) Sensitivity among Guanylate Kinases of Bacteria and Plants*

PubMed Central

Nomura, Yuhta; Izumi, Atsushi; Fukunaga, Yoshinori; Kusumi, Kensuke; Iba, Koh; Watanabe, Seiya; Nakahira, Yoichi; Weber, Andreas P. M.; Nozawa, Akira; Tozawa, Yuzuru

2014-01-01

The guanosine 3′,5′-bisdiphosphate (ppGpp) signaling system is shared by bacteria and plant chloroplasts, but its role in plants has remained unclear. Here we show that guanylate kinase (GK), a key enzyme in guanine nucleotide biosynthesis that catalyzes the conversion of GMP to GDP, is a target of regulation by ppGpp in chloroplasts of rice, pea, and Arabidopsis. Plants have two distinct types of GK that are localized to organelles (GKpm) or to the cytosol (GKc), with both enzymes being essential for growth and development. We found that the activity of rice GKpm in vitro was inhibited by ppGpp with a Ki of 2.8 μm relative to the substrate GMP, whereas the Km of this enzyme for GMP was 73 μm. The IC50 of ppGpp for GKpm was ∼10 μm. In contrast, the activity of rice GKc was insensitive to ppGpp, as was that of GK from bakers' yeast, which is also a cytosolic enzyme. These observations suggest that ppGpp plays a pivotal role in the regulation of GTP biosynthesis in chloroplasts through specific inhibition of GKpm activity, with the regulation of GTP biosynthesis in chloroplasts thus being independent of that in the cytosol. We also found that GKs of Escherichia coli and Synechococcus elongatus PCC 7942 are insensitive to ppGpp, in contrast to the ppGpp sensitivity of the Bacillus subtilis enzyme. Our biochemical characterization of GK enzymes has thus revealed a novel target of ppGpp in chloroplasts and has uncovered diversity among bacterial GKs with regard to regulation by ppGpp. PMID:24722991

A novel transmembrane Ser/Thr kinase complexes with protein phosphatase-1 and inhibitor-2.

PubMed

Wang, Hong; Brautigan, David L

2002-12-20

Protein kinases and protein phosphatases exert coordinated control over many essential cellular processes. Here, we describe the cloning and characterization of a novel human transmembrane protein KPI-2 (Kinase/Phosphatase/Inhibitor-2) that was identified by yeast two-hybrid using protein phosphatase inhibitor-2 (Inh2) as bait. KPI-2 mRNA was predominantly expressed in skeletal muscle. KPI-2 is a 1503-residue protein with two predicted transmembrane helices at the N terminus, a kinase domain, followed by a C-terminal domain. The transmembrane helices were sufficient for targeting proteins to the membrane. KPI-2 kinase domain has about 60% identity with its closest relative, a tyrosine kinase. However, it only exhibited serine/threonine kinase activity in autophosphorylation reactions or with added substrates. KPI-2 kinase domain phosphorylated protein phosphatase-1 (PP1C) at Thr(320), which attenuated PP1C activity. KPI-2 C-terminal domain directly associated with PP1C, and this required a VTF motif. Inh2 associated with KPI-2 C-terminal domain with and without PP1C. Thus, KPI-2 is a kinase with sites to associate with PP1C and Inh2 to form a regulatory complex that is localized to membranes.

Supplementation of Pork Patties with Bovine Plasma Protein Hydrolysates Augments Antioxidant Properties and Improves Quality.

PubMed

Seo, Hyun-Woo; Seo, Jin-Kyu; Yang, Han-Sul

2016-01-01

This study investigated the effects of bovine plasma protein (PP) hydrolysates on the antioxidant and quality properties of pork patties during storage. Pork patties were divided into 4 groups: without butylated hydroxytoluene (BHT) and PP hydrolysates (control), 0.02% BHT (T1), 1% PP hydrolysates (T2), and 2% PP hydrolysates (T3). Pork patty supplemented with PP hydrolysates had higher pH values and lower weight loss during cooking than the control patties. Results showed that lightness and hardness both decreased upon the addition of PP hydrolysates. All samples containing BHT and PP hydrolysates had reduced TBARS and peroxide values during storage. In particular, 2% PP hydrolysates were more effective in delaying lipid oxidation than were the other treatments. It was concluded that treatment with 2% PP hydrolysates can enhance the acceptance of pork patty.

The effect of meal frequency in a reduced-energy regimen on the gastrointestinal and appetite hormones in patients with type 2 diabetes: A randomised crossover study

PubMed Central

Belinova, Lenka; Kahleova, Hana; Oliyarnyk, Olena; Kazdova, Ludmila; Hill, Martin; Pelikanova, Terezie

2017-01-01

Background Appetite and gastrointestinal hormones (GIHs) participate in energy homeostasis, feeding behavior and regulation of body weight. We demonstrated previously the superior effect of a hypocaloric diet regimen with lower meal frequency (B2) on body weight, hepatic fat content, insulin sensitivity and feelings of hunger compared to the same diet divided into six smaller meals a day (A6). Studies with isoenergetic diet regimens indicate that lower meal frequency should also have an effect on fasting and postprandial responses of GIHs. The aim of this secondary analysis was to explore the effect of two hypocaloric diet regimens on fasting levels of appetite and GIHs and on their postprandial responses after a standard meal. It was hypothesized that lower meal frequency in a reduced-energy regimen leading to greater body weight reduction and reduced hunger would be associated with decreased plasma concentrations of GIHs: gastric inhibitory peptide (GIP), glucagon-like peptide-1(GLP-1), peptide YY(PYY), pancreatic polypeptide (PP) and leptin and increased plasma concentration of ghrelin. The postprandial response of satiety hormones (GLP-1, PYY and PP) and postprandial suppression of ghrelin will be improved. Methods In a randomized crossover study, 54 patients suffering from type 2 diabetes (T2D) underwent both regimens. The concentrations of GLP-1, GIP, PP, PYY, amylin, leptin and ghrelin were determined using multiplex immunoanalyses. Results Fasting leptin and GIP decreased in response to both regimens with no difference between the treatments (p = 0.37 and p = 0.83, respectively). Fasting ghrelin decreased in A6 and increased in B2 (with difference between regimens p = 0.023). Fasting PP increased in B2with no significant difference between regimens (p = 0.17). Neither GLP-1 nor PYY did change in either regimen. The decrease in body weight correlated negatively with changes in fasting ghrelin (r = -0.4, p<0.043) and the postprandial reduction of ghrelin correlated positively with its fasting level (r = 0.9, p<0.001). The postprandial responses of GIHs and appetite hormones were similar after both diet regimens. Conclusions Both hypocaloric diet regimens reduced fasting leptin and GIP and postprandial response of GIP comparably. The postprandial responses of GIHs and appetite hormones were similar after both diet regimens. Eating only breakfast and lunch increased fasting plasma ghrelin more than the same caloric restriction split into six meals. The changes in fasting ghrelin correlated negatively with the decrease in body weight. These results suggest that for type 2 diabetic patients on a hypocaloric diet, eating larger breakfast and lunch may be more efficient than six smaller meals during the day. PMID:28369078

Ultraviolet light-induced mutants of Streptococcus lactis subspecies diacetylactis with enhanced acid- or flavor-producing abilities

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

Kuila, R.K.; Ranganathan, B.

1978-04-01

A strain of Streptococcus lactis subspecies diacetylactis S/sub 1/ isolated from fresh milk was exposed to 7200 ergs/mm/sup 2/ of ultraviolet radiation. Over 8100 colonies surviving from 7.4 x 10/sup 6/ cells exposed to radiation were screened on citrate agar for detection and isolation of mutants with increased flavor and/or acid production. Of the survivors, 960 were type-I mutants that exhibited clear zone on citrate agar after 18 h (presumed to be high diacetyl producers), and 288 were type-II mutants which did not exhibit clear zones on citrate agar for up to 72 h (high acid producers). Type-II mutants producedmore » an average .93 percent titratable acidity which was 34 percent more than the .69 percent of the parent. Reduction in titratable acidity (56 percent less) was considerable in type-I mutants, compared with the parent culture. Diacetyl + acetoin production by type-I mutants was 137.9 ppM which has 4.5 times more than that of the parental strain. Acetaldehyde production in the mutants varied from 1.5 to 34.5 ppM (parent culture 3.0 ppM). The mutants with increased acid and high acetoin plus diacetyl production were stable after 50 subcultures in milk.« less

Fundamental role of the fostriecin unsaturated lactone and implications for selective protein phosphatase inhibition.

PubMed

Buck, Suzanne B; Hardouin, Christophe; Ichikawa, Satoshi; Soenen, Danielle R; Gauss, C-M; Hwang, Inkyu; Swingle, Mark R; Bonness, Kathy M; Honkanen, Richard E; Boger, Dale L

2003-12-24

Key derivatives and analogues of fostriecin were prepared and examined that revealed a fundamental role for the unsaturated lactone and confirmed the essential nature of the phosphate monoester. Thus, an identical 200-fold reduction in protein phosphatase 2A (PP2A) inhibition is observed with either the saturated lactone (7) or with an analogue that lacks the entire lactone (15). This 200-fold increase in PP2A inhibition attributable to the unsaturated lactone potentially may be due to reversible C269 alkylation within the PP beta12-beta13 active site loop accounting for PP2A/4 potency and selectivity.

Impact of fluid injection velocity on CO2 saturation and pore pressure in porous sandstone

NASA Astrophysics Data System (ADS)

Kitamura, Keigo; Honda, Hiroyuki; Takaki, Shinnosuke; Imasato, Mitsunori; Mitani, Yasuhiro

2017-04-01

The elucidation of CO2 behavior in sandstone is an essential issue to understand the fate of injecting CO2 in reservoirs. Injected CO2 invades pore spaces and replaces with resident brine and forms complex two-phase flow with brine. It is considered that this complex CO2 flow arises CO2 saturation (SCO_2)and pore fluid pressure(Pp) and makes various types of CO2 distribution pattern in pore space. The estimation of SCO_2 in the reservoir is one of important task in CCS projects. Fluid pressure (Pp) is also important to estimate the integrity of CO2 reservoir and overlying cap rocks. Generally, elastic waves are used to monitor the changes of SCO_2. Previous experimental and theoretical studies indicated that SCO_2 and Pp are controlled by the fluid velocity (flow rate) of invaded phase. In this study, we conducted the CO2 injection test for Berea sandstone (φ=18.1{%}) under deep CO2 reservoir conditions (confining pressure: 20MPa; temperature: 40 rC). We try to estimate the changes of SCO_2 and Pp with changing CO2 injection rate (FR) from 10 to 5000 μ l/min for Berea sandstone. P-wave velocities (Vp) are also measured during CO2 injection test and used to investigate the relationships between SCO2 and these geophysical parameters. We set three Vp-measurement channels (ch.1, ch2 and ch.3 from the bottom) monitor the CO2 behavior. The result shows step-wise SCO_2 changes with increasing FR from 9 to 25 {%} in low-FR condition (10-500 μ l/min). Vp also shows step wise change from ch1 to ch.3. The lowermost channel (ch.1) indicates that Vp-reduction stops around 4{%} at 10μ m/min condition. However, ch.3 changes slightly from 4{%} at 10 μ l/min to 5{%} at 100 μ l/min. On the other hand, differential Pp (Δ P) dose not shows obvious changes from 10kPa to 30kPa. Over 1000 μ l/min, SCO_2 increases from 35 to 47 {%}. Vp of all channels show slight reductions and Vp-reductions reach constant values as 8{%}, 6{%} and 8{%}, respectively at 5000{}μ l/min. On the other hand, Δ P shows rapid increasing from 50kPa to 500 kPa. It suggests a drastic change of CO2 behavior with injection rate. CO2 flows gently and enlarges SCO_2up to 25 {%} under low FR conditions without arisen Δ P (

Structure of the protein phosphatase 2A holoenzyme.

PubMed

Xu, Yanhui; Xing, Yongna; Chen, Yu; Chao, Yang; Lin, Zheng; Fan, Eugene; Yu, Jong W; Strack, Stefan; Jeffrey, Philip D; Shi, Yigong

2006-12-15

Protein Phosphatase 2A (PP2A) plays an essential role in many aspects of cellular physiology. The PP2A holoenzyme consists of a heterodimeric core enzyme, which comprises a scaffolding subunit and a catalytic subunit, and a variable regulatory subunit. Here we report the crystal structure of the heterotrimeric PP2A holoenzyme involving the regulatory subunit B'/B56/PR61. Surprisingly, the B'/PR61 subunit has a HEAT-like (huntingtin-elongation-A subunit-TOR-like) repeat structure, similar to that of the scaffolding subunit. The regulatory B'/B56/PR61 subunit simultaneously interacts with the catalytic subunit as well as the conserved ridge of the scaffolding subunit. The carboxyterminus of the catalytic subunit recognizes a surface groove at the interface between the B'/B56/PR61 subunit and the scaffolding subunit. Compared to the scaffolding subunit in the PP2A core enzyme, formation of the holoenzyme forces the scaffolding subunit to undergo pronounced conformational rearrangements. This structure reveals significant ramifications for understanding the function and regulation of PP2A.

Detection of PR-39, a porcine host defence peptide, in different cell sub-linages in pigs infected with Actinobacillus pleuropneumoniae.

PubMed

Gabner, S; Egerbacher, M; Gasse, H; Hewicker-Trautwein, M; Höltig, D; Waldmann, K-H; Blecha, F; Saalmüller, A; Hennig-Pauka, I

2017-10-01

Innate immunity is critically important for the outcome of infection in many diseases. It was previously shown that cathelicidin PR-39, an important porcine multifunctional host defence peptide, is elevated in bronchoalveolar lavage fluid and respiratory tract tissue after experimental infection with Actinobacillus pleuropneumoniae (A.pp.). To date, neutrophil polymorphonuclear leukocytes (PMNs) are thought to be the only source of PR-39. The aim of this study was to further characterize PR-39⁺ cells and selected immune cell populations in lung tissue during the peracute (7-10 hours), acute (2 days), reconvalescent (7 days) and chronic (21 days) stages of experimental infection with A.pp. serotype 2. In total, six mock-infected control pigs and 12 infected pigs were examined. Using immunofluorescence double-labeling, antibodies against PR-39 were combined with antibodies against CD3 (T-cells), CD79 (B-cells), Iba1 (activated macrophages), TTF-1 (lung epithelial cells expressing surfactant proteins), macrophage/L1 protein and myeloperoxidase (MPO, cells of the myeloid linage). In the peracute and acute phases of infection, total PR-39⁺ cells and myeloid linage cells increased, whereas CD3⁺ cells and TTF-1⁺ cells decreased. Double labeling revealed that most Macrophage/L1 protein+ cells and to a lesser extent MPO⁺ cells co-expressed PR-39. In addition, few bronchial epithelial cells and type 2 alveolar epithelial cells (both identified with TTF-1) produced PR-39. Occasionally, CD3⁺ T cells expressing PR-39 were seen in infected animals. Taken together, this study identifies cell types, other than PMNs, in lungs of A.pp.-infected pigs that are capable of producing PR-39. In addition, these findings provide further insights into the dynamics of different immune cell populations during A.pp.-infection.

Co-pyrolysis of rice straw and polypropylene using fixed-bed pyrolyzer

NASA Astrophysics Data System (ADS)

Izzatie, N. I.; Basha, M. H.; Uemura, Y.; Mazlan, M. A.; Hashim, M. S. M.; Amin, N. A. M.; Hamid, M. F.

2016-11-01

The present work encompasses the impact of temperature (450, 500, 550, 600 °C) on the properties of pyrolysis oil and on other product yield for the co-pyrolysis of Polypropylene (PP) plastics and rice straw. Co-pyrolysis of PP plastic and rice straw were conducted in a fixed-bed drop type pyrolyzer under an inert condition to attain maximum oil yield. Physically, the pyrolysis oil is dark-brown in colour with free flowing and has a strong acrid smell. Copyrolysis between these typically obtained in maximum pyrolysis oil yields up to 69% by ratio 1:1 at a maximum temperature of 550 °C. From the maximum yield of pyrolysis oil, characterization of pyrolysis product and effect of biomass type of the composition were evaluated. Pyrolysis oil contains a high water content of 66.137 wt.%. Furfural, 2- methylnaphthalene, tetrahydrofuran (THF), toluene and acetaldehyde were the major organic compounds found in pyrolysis oil of rice straw mixed with PP. Bio-char collected from co-pyrolysis of rice straw mixed with PP plastic has high calorific value of 21.190 kJ/g and also carbon content with 59.02 wt.% and could contribute to high heating value. The non-condensable gases consist of hydrogen, carbon monoxide, and methane as the major gas components.

The combinatorial PP1-binding consensus Motif (R/K)x( (0,1))V/IxFxx(R/K)x(R/K) is a new apoptotic signature.

PubMed

Godet, Angélique N; Guergnon, Julien; Maire, Virginie; Croset, Amélie; Garcia, Alphonse

2010-04-01

Previous studies established that PP1 is a target for Bcl-2 proteins and an important regulator of apoptosis. The two distinct functional PP1 consensus docking motifs, R/Kx((0,1))V/IxF and FxxR/KxR/K, involved in PP1 binding and cell death were previously characterized in the BH1 and BH3 domains of some Bcl-2 proteins. In this study, we demonstrate that DPT-AIF(1), a peptide containing the AIF(562-571) sequence located in a c-terminal domain of AIF, is a new PP1 interacting and cell penetrating molecule. We also showed that DPT-AIF(1) provoked apoptosis in several human cell lines. Furthermore, DPT-APAF(1) a bi-partite cell penetrating peptide containing APAF-1(122-131), a non penetrating sequence from APAF-1 protein, linked to our previously described DPT-sh1 peptide shuttle, is also a PP1-interacting death molecule. Both AIF(562-571) and APAF-1(122-131) sequences contain a common R/Kx((0,1))V/IxFxxR/KxR/K motif, shared by several proteins involved in control of cell survival pathways. This motif combines the two distinct PP1c consensus docking motifs initially identified in some Bcl-2 proteins. Interestingly DPT-AIF(2) and DPT-APAF(2) that carry a F to A mutation within this combinatorial motif, no longer exhibited any PP1c binding or apoptotic effects. Moreover the F to A mutation in DPT-AIF(2) also suppressed cell penetration. These results indicate that the combinatorial PP1c docking motif R/Kx((0,1))V/IxFxxR/KxR/K, deduced from AIF(562-571) and APAF-1(122-131) sequences, is a new PP1c-dependent Apoptotic Signature. This motif is also a new tool for drug design that could be used to characterize potential anti-tumour molecules.

Treatment of recent-onset type 1 diabetic patients with DiaPep277: results of a double-blind, placebo-controlled, randomized phase 3 trial.

PubMed

Raz, Itamar; Ziegler, Anette G; Linn, Thomas; Schernthaner, Guntram; Bonnici, Francois; Distiller, Larry A; Giordano, Carla; Giorgino, Francesco; de Vries, Liat; Mauricio, Didac; Procházka, Vlastimil; Wainstein, Julio; Elias, Dana; Avron, Ann; Tamir, Merana; Eren, Rachel; Peled, Dana; Dagan, Shlomo; Cohen, Irun R; Pozzilli, Paolo

2014-01-01

To evaluate safety and efficacy of DiaPep277 in preserving β-cell function in type 1 diabetic patients. DIA-AID 1 is a multinational, phase 3, balanced-randomized, double-blind, placebo-controlled, parallel-group clinical study. Newly diagnosed patients (N = 457, aged 16-45 years) were randomized to subcutaneous injections of DiaPep277 or placebo quarterly for 2 years. The primary efficacy end point was the change from baseline in the area under the glucagon-stimulated C-peptide curve. Secondary end points were the change from baseline in mixed-meal stimulated C-peptide secretion and in fasting C-peptide and achieving target HbA1c ≤7% (≤53 mmol/mol). Partial remission (target HbA1c on insulin ≤0.5 units/kg/day) and hypoglycemic event rate were exploratory end points. DiaPep277 was safe and well tolerated. Significant preservation of C-peptide secretion was observed in the DiaPep277-treated group compared with the placebo (relative treatment effects of 23.4%, P = 0.037, and 29.2%, P = 0.011, in the modified intent-to-treat [mITT] and per-protocol [PP] populations, respectively). The mixed-meal stimulation failed to distinguish between the groups. There was a trend toward efficacy in fasting C-peptide levels, though not statistically significant. Significantly more DiaPep277-treated than placebo-treated patients maintained target HbA1c (mITT 56% versus 44%, P = 0.03; PP 60% versus 45%, P = 0.0082) and entered partial remission (mITT 38% versus 29%, P = 0.08; PP 42% versus 30%, P = 0.035). DiaPep277 treatment reduced the relative hypoglycemic event risk (mITT by 20%; PP by 28%). DiaPep277 safely contributes to preservation of β-cell function and to improved glycemic control in patients with type 1 diabetes.

An Enterotoxin-Like Binary Protein from Pseudomonas protegens with Potent Nematicidal Activity.

PubMed

Wei, Jun-Zhi; Siehl, Daniel L; Hou, Zhenglin; Rosen, Barbara; Oral, Jarred; Taylor, Christopher G; Wu, Gusui

2017-10-01

Soil microbes are a major food source for free-living soil nematodes. It is known that certain soil bacteria have evolved systems to combat predation. We identified the nematode-antagonistic Pseudomonas protegens strain 15G2 from screening of microbes. Through protein purification we identified a binary protein, designated Pp-ANP, which is responsible for the nematicidal activity. This binary protein inhibits Caenorhabditis elegans growth and development by arresting larvae at the L1 stage and killing older-staged worms. The two subunits, Pp-ANP1a and Pp-ANP2a, are active when reconstituted from separate expression in Escherichia coli The binary toxin also shows strong nematicidal activity against three other free-living nematodes ( Pristionchus pacificus , Panagrellus redivivus , and Acrobeloides sp.), but we did not find any activity against insects and fungi under test conditions, indicating specificity for nematodes. Pp-ANP1a has no significant identity to any known proteins, while Pp-ANP2a shows ∼30% identity to E. coli heat-labile enterotoxin (LT) subunit A and cholera toxin (CT) subunit A. Protein modeling indicates that Pp-ANP2a is structurally similar to CT/LT and likely acts as an ADP-ribosyltransferase. Despite the similarity, Pp-ANP shows several characteristics distinct from CT/LT toxins. Our results indicate that Pp-ANP is a new enterotoxin-like binary toxin with potent and specific activity to nematodes. The potency and specificity of Pp-ANP suggest applications in controlling parasitic nematodes and open an avenue for further research on its mechanism of action and role in bacterium-nematode interaction. IMPORTANCE This study reports the discovery of a new enterotoxin-like binary protein, Pp-ANP, from a Pseudomonas protegens strain. Pp-ANP shows strong nematicidal activity against Caenorhabditis elegans larvae and older-staged worms. It also shows strong activity on other free-living nematodes ( Pristionchus pacificus , Panagrellus redivivus , and Acrobeloides sp.). The two subunits, Pp-ANP1a and Pp-ANP2a, can be expressed separately and reconstituted to form the active complex. Pp-ANP shows some distinct characteristics compared with other toxins, including Escherichia coli enterotoxin and cholera toxin. The present study indicates that Pp-ANP is a novel binary toxin and that it has potential applications in controlling parasitic nematodes and in studying toxin-host interaction. Copyright © 2017 Wei et al.

Uranium hydrogeochemical and stream sediment reconnaissance of the Albuquerque NTMS Quadrangle, New Mexico, including concentrations of forty-three additional elements

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

Maassen, L.W.; Bolivar, S.L.

1979-06-01

The Los Alamos Scientific Laboratory conducted a hydrogeochemical and stream sediment reconnaissance for uranium. Totals of 408 water and 1538 sediment samples were collected from 1802 locations over a 20 100-km/sup 2/ area at an average density of one location per 11 km/sup 2/. Water samples were collected from springs, wells, and streams; sediments samples were collected predominantly from streams, but also from springs. All water samples were analyzed for uranium and 12 other elements. Sediment samples were analyzed for uranium and 42 additional elements. The uranium concentrations in water samples range from below the detection limit of 0.02 ppBmore » to 194.06 ppB. The mean uranium concentration for all water types containing < 40 ppB uranium is 1.98 ppB. Six samples contained uranium concentrations > 40.00 ppB. Well waters have the highest mean uranium concentration; spring waters have the lowest. Clusters of water samples that contain anomalous uranium concentrations are delineated in nine areas. Sediments collected from the quadrangle have uranium concentrations that range between 0.63 ppM and 28.52 ppM, with a mean for all sediments of 3.53 ppM. Eight areas containing clusters of sediments with anomalous uranium concentrations are delineated. One cluster contains sample locations within the Ambrosia Lake uranium district. Five clusters of sediment samples with anomalous uranium concentrations were collected from streams that drain the Jemez volcanic field. Another cluster defines an area just northeast of Albuquerque where streams drain Precambrian rocks, predominantly granites, of the Sandia Mountains. The last cluster, consisting of spring sediments from Mesa Portales, was collected near the contact of the Tertiary Ojo Alamo sandstone with underlying Cretaceous sediments. Sediments from these springs exhibit some of the highest uranium values reported and are associated with high uranium/thorium ratios.« less

Functional studies of ATP sulfurylase from Penicillium chrysogenum

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

Seubert, P.A.

1985-01-01

ATP sulfurylase from Penicillium chrysogenum has a specific activity (V/sub max/) of 6-7 units x mg protein/sup -1/ determined with the physiological substrates of MgATP and SO/sub 4//sup 2 -/ and assayed by (A) initial velocity measurements with APS kinase and inorganic pyrophosphatase present and (B) analysis of nonlinear reaction progress curves. The fact both assays give the same results show the intrinsic activity of ATP sulfurylase is much higher than previously reported. In initial velocity dead-end inhibition studies, the sulfate analog S/sub 2/O/sub 3//sup 2 -/ is a competitive inhibitor of SO/sub 42/..sqrt.. and a noncompetitive inhibitor of MgATP.more » Monovalent oxyanions such as NO/sub 3//sup -/, ClO/sub 3//sup -/, ClO/sub 4//sup -/, and FSO/sub 3//sup -/ behave as uncompetitive inhibitors of MgATP and thus seem not to be true sulfate analogs. The reverse reaction was assayed by the pyrophosphate dependent release of /sup 35/SO/sub 4//sup 2 -/ from AP/sup 35/S. Product inhibition by MgATP or SO/sub 4//sup 2 -/ is competitive with APS and mixed-type with PP/sub i/. Imidodiphosphate can serve as an alternative substrate for PP/sub i/. ATP sulfurylase binds (but does not hydrolyze) APS. A Scatchard plot of the APS binding is nonlinear, suggesting at least two types of sites. The cumulative results are qualitatively consistent with the random addition of MgATP and SO/sub 4//sup 2 -/ and the ordered release of first MgPP/sub i/ then APS, with APS release being partially rate limiting. Certain quantitative discrepancies suggest either an unknown variable (e.g. enzyme concentration) complicates the analysis or, in light of binding studies that the actual mechanism is more complicated (e.g. alternating sites) than any of the conventional models examined.« less

Epigallocatechin-3-gallate and penta-O-galloyl-β-D-glucose inhibit protein phosphatase-1.

PubMed

Kiss, Andrea; Bécsi, Bálint; Kolozsvári, Bernadett; Komáromi, István; Kövér, Katalin E; Erdődi, Ferenc

2013-01-01

Protein phosphatase-1 (PP1) and protein phosphatase-2A (PP2A) are responsible for the dephosphorylation of the majority of phosphoserine/threonine residues in cells. In this study, we show that (-)-epigallocatechin-3-gallate (EGCG) and 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), polyphenolic constituents of green tea and tannins, inhibit the activity of the PP1 recombinant δ-isoform of the PP1 catalytic subunit and the native PP1 catalytic subunit (PP1c) with IC(50) values of 0.47-1.35 μm and 0.26-0.4 μm, respectively. EGCG and PGG inhibit PP2Ac less potently, with IC(50) values of 15 and 6.6 μm, respectively. The structure-inhibitory potency relationships of catechin derivatives suggests that the galloyl group may play a major role in phosphatase inhibition. The interaction of EGCG and PGG with PP1c was characterized by NMR and surface plasmon resonance-based binding techniques. Competitive binding assays and molecular modeling suggest that EGCG docks at the hydrophobic groove close to the catalytic center of PP1c, partially overlapping with the binding surface of microcystin-LR or okadaic acid. This hydrophobic interaction is further stabilized by hydrogen bonding via hydroxyl/oxo groups of EGCG to PP1c residues. Comparative docking shows that EGCG binds to PP2Ac in a similar manner, but in a distinct pose. Long-term treatment (24 h) with these compounds and other catechins suppresses the viability of HeLa cells with a relative effectiveness reminiscent of their in vitro PP1c-inhibitory potencies. The above data imply that the phosphatase-inhibitory features of these polyphenols may be implicated in the wide spectrum of their physiological influence. © 2012 The Authors Journal compilation © 2012 FEBS.

Donation return time at fixed and mobile donation sites

PubMed Central

Carey, Patricia M.; High, Patrick M.; Schlumpf, Karen S.; Johnson, Bryce R.; Mast, Alan E.; Rios, Jorge A.; Simon, Toby L.; Wilkinson, Susan L.

2013-01-01

BACKGROUND This study investigated the effect of blood donation environment, fixed or mobile with differing sponsor types, on donation return time. STUDY DESIGN AND METHODS Data from 2006 through 2009 at six US blood centers participating in the Retrovirus Epidemiology Donor Study-II (REDS-II) were used for analysis. Descriptive statistics stratified by whole blood (WB), plateletpheresis (PP), and double red blood cell (R2) donations were obtained for fixed and mobile locations, including median number of donations and median interdonation interval. A survival analysis estimated median return time at fixed and mobile sites, while controlling for censored return times, demographics, blood center, and mandatory recovery times. RESULTS Two-thirds (67.9%) of WB donations were made at mobile sites, 97.4% of PP donations were made at fixed sites, and R2 donations were equally distributed between fixed and mobile locations. For donations at fixed sites only or alternating between fixed and mobile sites, the highest median numbers of donations were nine and eight, respectively, and the shortest model-adjusted median return times (controlling for mandatory eligibility times of 56 and 112 days) were 36 and 30 days for WB and R2 donations, respectively. For PP donations, the shortest model-adjusted median return time was 23 days at a fixed location and the longest was 693 days at community locations. CONCLUSION WB, PP, and R2 donors with the shortest time between donations were associated with fixed locations and those alternating between fixed and mobile locations, even after controlling for differing mandatory recovery times for the different blood donation procedures. PMID:21745215

Suitability of Secondary PEEK Telescopic Crowns on Zirconia Primary Crowns: The Influence of Fabrication Method and Taper.

PubMed

Merk, Susanne; Wagner, Christina; Stock, Veronika; Eichberger, Marlis; Schmidlin, Patrick R; Roos, Malgorzata; Stawarczyk, Bogna

2016-11-08

This study investigates the retention load (RL) between ZrO₂ primary crowns and secondary polyetheretherketone (PEEK) crowns made by different fabrication methods with three different tapers. Standardized primary ZrO₂ crowns were fabricated with three different tapers: 0°, 1°, and 2° ( n = 10/group). Ten secondary crowns were fabricated (i) milled from breCam BioHPP blanks (PM); (ii) pressed from industrially fabricated PEEK pellets (PP) (BioHPP Pellet); or (iii) pressed from granular PEEK (PG) (BioHPP Granulat). One calibrated operator adjusted all crowns. In total, the RL of 90 secondary crowns were measured in pull-off tests at 50 mm/min, and each specimen was tested 20 times. Two- and one-way ANOVAs followed by a Scheffé's post-hoc test were used for data analysis ( p < 0.05). Within crowns with a 0° taper, the PP group showed significantly higher retention load values compared with the other groups. Among the 1° taper, the PM group presented significantly lower retention loads than the PP group. However, the pressing type had no impact on the results. Within the 2° taper, the fabrication method had no influence on the RL. Within the PM group, the 2° taper showed significantly higher retention load compared with the 1° taper. The taper with 0° was in the same range value as the 1° and 2° tapers. No impact of the taper on the retention value was observed between the PP groups. Within the PG groups, the 0° taper presented significantly lower RL than the 1° taper, whereas the 2° taper showed no differences. The fabrication method of the secondary PEEK crowns and taper angles showed no consistent effect within all tested groups.

Evaluation of Pump Pulsation in Respirable Size-Selective Sampling: Part III. Investigation of European Standard Methods

PubMed Central

Soo, Jhy-Charm; Lee, Eun Gyung; Lee, Larry A.; Kashon, Michael L.; Harper, Martin

2015-01-01

Lee et al. (Evaluation of pump pulsation in respirable size-selective sampling: part I. Pulsation measurements. Ann Occup Hyg 2014a;58:60–73) introduced an approach to measure pump pulsation (PP) using a real-world sampling train, while the European Standards (EN) (EN 1232-1997 and EN 12919-1999) suggest measuring PP using a resistor in place of the sampler. The goal of this study is to characterize PP according to both EN methods and to determine the relationship of PP between the published method (Lee et al., 2014a) and the EN methods. Additional test parameters were investigated to determine whether the test conditions suggested by the EN methods were appropriate for measuring pulsations. Experiments were conducted using a factorial combination of personal sampling pumps (six medium- and two high-volumetric flow rate pumps), back pressures (six medium- and seven high-flow rate pumps), resistors (two types), tubing lengths between a pump and resistor (60 and 90 cm), and different flow rates (2 and 2.5 l min−1 for the medium- and 4.4, 10, and 11.2 l min−1 for the high-flow rate pumps). The selection of sampling pumps and the ranges of back pressure were based on measurements obtained in the previous study (Lee et al., 2014a). Among six medium-flow rate pumps, only the Gilian5000 and the Apex IS conformed to the 10% criterion specified in EN 1232-1997. Although the AirChek XR5000 exceeded the 10% limit, the average PP (10.9%) was close to the criterion. One high-flow rate pump, the Legacy (PP = 8.1%), conformed to the 10% criterion in EN 12919-1999, while the Elite12 did not (PP = 18.3%). Conducting supplemental tests with additional test parameters beyond those used in the two subject EN standards did not strengthen the characterization of PPs. For the selected test conditions, a linear regression model [PPEN = 0.014 + 0.375 × PPNIOSH (adjusted R2 = 0.871)] was developed to determine the PP relationship between the published method (Lee et al., 2014a) and the EN methods. The 25% PP criterion recommended by Lee et al. (2014a), average value derived from repetitive measurements, corresponds to 11% PPEN. The 10% pass/fail criterion in the EN Standards is not based on extensive laboratory evaluation and would unreasonably exclude at least one pump (i.e. AirChek XR5000 in this study) and, therefore, the more accurate criterion of average 11% from repetitive measurements should be substituted. This study suggests that users can measure PP using either a real-world sampling train or a resistor setup and obtain equivalent findings by applying the model herein derived. The findings of this study will be delivered to the consensus committees to be considered when those standards, including the EN 1232-1997, EN 12919-1999, and ISO 13137-2013, are revised. PMID:25053700

Rigid, Perfectly Plastic Analysis of Ring-Stiffened Shells Under Dynamic Loading

DTIC Science & Technology

1986-08-01

Elastic-Viscoplastic Response of Clamped Beams Under Uniformly Distributed Impulse, Technical Report AFML-TR-68-396, Jan 1969. 15. Save , M. A. and...Edition, 1959, pp. 466-471 (Chapter 15). A-4. Save , M. A. and Massonnett, C. E., Plastic Analysis and Design of Plates, Shells, and Discs, North-Holland...TYPE TYESHORT (2 ɞ) HIGH LOAnD p > I + CONDITIONS u C 2 (-1) 0 T 1 0 x < MOMENT m Ix, T) 2 +1 OR -RESULTANT Lxo u.=-g- MEMBRANE n,= RESULTANT

Progesterone-associated proteins PP12 and PP14 in the human endometrium.

PubMed

Rutanen, E M; Koistinen, R; Seppälä, M; Julkunen, M; Suikkari, A M; Huhtala, M L

1987-01-01

Two proteins, designated as PP12 and PP14 were originally isolated from soluble extracts of the human placenta and its adjacent membranes. We have shown that they are synthesized by decidualized/secretory endometrium and not by placenta. Both proteins occur at high concentrations in human amniotic fluid, which is therefore an excellent source for purification. PP12 is a 34-kDa glycoprotein, which has an N-terminal amino acid sequence of Ala-Pro-Trp-Gln-Cys-Ala-Pro-Cys-Ser-Ala. This is identical with that of somatomedin-binding protein purified from the amniotic fluid. PP12 too binds somatomedin-C, or IGF-I (insulin-like growth factor-I). Human secretory endometrium synthesizes and secretes PP12, and progesterone stimulates its secretion. PP14 is a 28-kDa glycoprotein. Its N-terminal sequence shows homology to that of beta-lactoglobulins from various species. We have found PP14 in the human endometrium, serum and milk. Immunologically, PP14 is related to progestagen-associated endometrial protein (PEP), alpha-2 pregnancy-associated endometrial protein (alpha-2, PEG), endometrial protein 15 (EP15), alpha-uterine protein (AUP) and chorionic alpha-2 microglobulin (CAG-2). In ovulatory menstrual cycles, the concentration of PP14 increases in endometrial tissue as the secretory changes advance. In serum, the PP14 concentration begins to rise later than the progesterone levels, and high serum PP14 levels are maintained for the first days of the next cycle. By contrast, no elevation of serum PP14 level is seen in anovulatory cycles. Our results show that progesterone-associated proteins are synthesized by the human endometrium and appear in the peripheral circulation, where they can be quantitatively measured using immunochemical techniques.

Improvements of ambient hyperglycemia and glycemic variability are associated with reduction in oxidative stress for patients with type 2 diabetes.

PubMed

Ohara, Makoto; Nagaike, Hiroe; Goto, Satoshi; Fukase, Ayako; Tanabe, Yuki; Tomoyasu, Masako; Yamamoto, Takeshi; Hayashi, Toshiyuki; Fukui, Tomoyasu; Hirano, Tsutomu

2018-05-01

We aimed to evaluate which parameters of improvement in glucose metabolism reduce oxidative stress for patients with Type 2 diabetes mellitus (T2DM). Sixty-seven outpatients with T2DM underwent 72 h of continuous glucose monitoring (CGM) and were measured for oxidative stress before and after a 24-week intervention with the following targets: fasting plasma glucose (FPG), <130 mg/dl; postprandial plasma glucose (PPG), <180 mg/dl; and glycated hemoglobin (HbA1c), <7% (53 mmol/mol). The mean glucose level (MGL), mean amplitude of glycemic excursions (MAGE), mean of daily differences (MODD), percentage coefficient of variation for glucose (%CV) and area under the postprandial plasma glucose curve (AUC PP ) were calculated from the CGM data. Oxidative stress was estimated using the diacron-reactive oxygen metabolites (d-ROMs) test. Finally, the association between the improvements in glucose metabolism and oxidative stress was evaluated. FPG, MGL, HbA1c, MAGE, MODD, %CV, AUC PP , and d-ROMs significantly improved after 24 weeks of intervention. The change in d-ROMs was significantly correlated with that in FPG (r = 0.414), MGL (r = 0.402), HbA1c (r = 0.271), MAGE (r = 0.457), MODD (r = 0.371), and AUC PP (r = 0.352). The correlation of the change in d-ROMs with that in FPG, MAGE, and MODD and the use of glucose-like peptide 1 receptor agonists and statins remained significant after adjustment for other markers of diabetes control (multiple R 2 = 0.406). Improvements in glucose metabolism, including FPG and daily and day-to-day glucose variability, were all correlated with reduced oxidative stress for patients with T2DM. Published by Elsevier B.V.

RANKL is necessary and sufficient to initiate development of antigen-sampling M cells in the intestinal epithelium.

PubMed

Knoop, Kathryn A; Kumar, Nachiket; Butler, Betsy R; Sakthivel, Senthilkumar K; Taylor, Rebekah T; Nochi, Tomonori; Akiba, Hisaya; Yagita, Hideo; Kiyono, Hiroshi; Williams, Ifor R

2009-11-01

Microfold cells (M cells) are specialized epithelial cells situated over Peyer's patches (PP) and other organized mucosal lymphoid tissues that transport commensal bacteria and other particulate Ags into intraepithelial pockets accessed by APCs. The TNF superfamily member receptor activator of NF-kappaB ligand (RANKL) is selectively expressed by subepithelial stromal cells in PP domes. We found that RANKL null mice have <2% of wild-type levels of PP M cells and markedly diminished uptake of 200 nm diameter fluorescent beads. Ab-mediated neutralization of RANKL in adult wild-type mice also eliminated most PP M cells. The M cell deficit in RANKL null mice was corrected by systemic administration of exogenous RANKL. Treatment with RANKL also induced the differentiation of villous M cells on all small intestinal villi with the capacity for avid uptake of Salmonella and Yersinia organisms and fluorescent beads. The RANK receptor for RANKL is expressed by epithelial cells throughout the small intestine. We conclude that availability of RANKL is the critical factor controlling the differentiation of M cells from RANK-expressing intestinal epithelial precursor cells.

Which type of placenta previa requires blood transfusion more frequently? A new concept of indiscernible edge total previa.

PubMed

Baba, Yosuke; Takahashi, Hironori; Ohkuchi, Akihide; Usui, Rie; Matsubara, Shigeki

2016-11-01

During cesarean section (CS) for placenta previa (PP), the size/area/portion of the lower uterine segment occupied by the placenta may affect the bleeding amount and the subsequent need for a blood transfusion (BT). We propose a new concept, indiscernible edge total PP (IEPP), when vaginal ultrasound does not discern the lower placental edge because the placenta covers the visible lower segment. We characterized IEPP, focusing on its allogeneic BT requirement. We classified PP (n = 307) into four types: marginal, partial, discernible edge total PP (DEPP) and IEPP: internal ostium (os)-placental edge distance measurable or unmeasurable on vaginal ultrasound in DEPP or IEPP, respectively. We determined the clinical characteristics according to the four types; the relationship between the intraoperative blood loss and os-edge distance in DEPP; and risk factors for allogeneic BT. The following were significantly higher/larger in cases of IEPP: previous CS; anterior placentation; lacunae; elective cesarean hysterectomy; intraoperative blood loss; autologous BT; allogeneic BT; intensive care unit admission; and an abnormally invasive placenta (AIP). In DEPP, the os-edge distance was weakly correlated with the bleeding amount (r = 0.214). Multivariate logistic regression analysis showed that previous CS, lacunae, AIP and IEPP were independent risk factors for allogeneic BT (odds ratios 3.8, 3.1, 13.8 and 4.6, respectively). After excluding patients undergoing hemostatic procedures during CS, IEPP remained the only independent risk factor for allogeneic BT (odds ratio 5.2). The new concept of IEPP may be useful for predicting BT in CS for patients with PP. © 2016 Japan Society of Obstetrics and Gynecology.

[Individual psychological features in patients with computer game addiction suffering and predisposed persons].

PubMed

Kardashian, R A

2018-01-01

To study personality characteristics in adolescents with computer game addiction. The study included students of grades 7 to 10 at the age of 12-17 years (14.6±2.4 years), their parents and school teachers. The results of a study showed the following combination in patients: 'genophilic' type of DPT with schizoid personality accentuation and 'projection' type of psychological protection, and 'dignitophilic' type of DPT with labile personality accentuation and 'denial' type of PP.

Overexpression of the protein phosphatase 2A regulatory subunit a gene ZmPP2AA1 improves low phosphate tolerance by remodeling the root system architecture of maize

PubMed Central

Wang, Jiemin; Pei, Laming; Jin, Zhe; Zhang, Kewei; Zhang, Juren

2017-01-01

Phosphate (Pi) limitation is a constraint for plant growth and development in many natural and agricultural ecosystems. In this study, a gene encoding Zea mays L. protein phosphatase 2A regulatory subunit A, designated ZmPP2AA1, was induced in roots by low Pi availability. The function of the ZmPP2AA1 gene in maize was analyzed using overexpression and RNA interference. ZmPP2AA1 modulated root gravitropism, negatively regulated primary root (PR) growth, and stimulated the development of lateral roots (LRs). A detailed characterization of the root system architecture (RSA) in response to different Pi concentrations with or without indole-3-acetic acid and 1-N-naphthylphthalamic acid revealed that auxin was involved in the RSA response to low Pi availability. Overexpression of ZmPP2AA1 enhanced tolerance to Pi starvation in transgenic maize in hydroponic and soil pot experiments. An increased dry weight (DW), root-to-shoot ratio, and total P content and concentration, along with a delayed and reduced accumulation of anthocyanin in overexpressing transgenic maize plants coincided with their highly branched root system and increased Pi uptake capability under low Pi conditions. Inflorescence development of the ZmPP2AA1 overexpressing line was less affected by low Pi stress, resulting in higher grain yield per plant under Pi deprivation. These data reveal the biological function of ZmPP2AA1, provide insights into a linkage between auxin and low Pi responses, and drive new strategies for the efficient utilization of Pi by maize. PMID:28448624

An ABA-mimicking ligand that reduces water loss and promotes drought resistance in plants

PubMed Central

Cao, Minjie; Liu, Xue; Zhang, Yan; Xue, Xiaoqian; Zhou, X Edward; Melcher, Karsten; Gao, Pan; Wang, Fuxing; Zeng, Liang; Zhao, Yang; Zhao, Yang; Deng, Pan; Zhong, Dafang; Zhu, Jian-Kang; Xu, H Eric; Xu, Yong

2013-01-01

Abscisic acid (ABA) is the most important hormone for plants to resist drought and other abiotic stresses. ABA binds directly to the PYR/PYL family of ABA receptors, resulting in inhibition of type 2C phosphatases (PP2C) and activation of downstream ABA signaling. It is envisioned that intervention of ABA signaling by small molecules could help plants to overcome abiotic stresses such as drought, cold and soil salinity. However, chemical instability and rapid catabolism by plant enzymes limit the practical application of ABA itself. Here we report the identification of a small molecule ABA mimic (AM1) that acts as a potent activator of multiple members of the family of ABA receptors. In Arabidopsis, AM1 activates a gene network that is highly similar to that induced by ABA. Treatments with AM1 inhibit seed germination, prevent leaf water loss, and promote drought resistance. We solved the crystal structure of AM1 in complex with the PYL2 ABA receptor and the HAB1 PP2C, which revealed that AM1 mediates a gate-latch-lock interacting network, a structural feature that is conserved in the ABA-bound receptor/PP2C complex. Together, these results demonstrate that a single small molecule ABA mimic can activate multiple ABA receptors and protect plants from water loss and drought stress. Moreover, the AM1 complex crystal structure provides a structural basis for designing the next generation of ABA-mimicking small molecules. PMID:23835477

The core regulatory network of the abscisic acid pathway in banana: genome-wide identification and expression analyses during development, ripening, and abiotic stress.

PubMed

Hu, Wei; Yan, Yan; Shi, Haitao; Liu, Juhua; Miao, Hongxia; Tie, Weiwei; Ding, Zehong; Ding, XuPo; Wu, Chunlai; Liu, Yang; Wang, Jiashui; Xu, Biyu; Jin, Zhiqiang

2017-08-29

Abscisic acid (ABA) signaling plays a crucial role in developmental and environmental adaptation processes of plants. However, the PYL-PP2C-SnRK2 families that function as the core components of ABA signaling are not well understood in banana. In the present study, 24 PYL, 87 PP2C, and 11 SnRK2 genes were identified from banana, which was further supported by evolutionary relationships, conserved motif and gene structure analyses. The comprehensive transcriptomic analyses showed that banana PYL-PP2C-SnRK2 genes are involved in tissue development, fruit development and ripening, and response to abiotic stress in two cultivated varieties. Moreover, comparative expression analyses of PYL-PP2C-SnRK2 genes between BaXi Jiao (BX) and Fen Jiao (FJ) revealed that PYL-PP2C-SnRK2-mediated ABA signaling might positively regulate banana fruit ripening and tolerance to cold, salt, and osmotic stresses. Finally, interaction networks and co-expression assays demonstrated that the core components of ABA signaling were more active in FJ than in BX in response to abiotic stress, further supporting the crucial role of the genes in tolerance to abiotic stress in banana. This study provides new insights into the complicated transcriptional control of PYL-PP2C-SnRK2 genes, improves the understanding of PYL-PP2C-SnRK2-mediated ABA signaling in the regulation of fruit development, ripening, and response to abiotic stress, and identifies some candidate genes for genetic improvement of banana.

The Effects of Management Support on the Successful Implementation of Group Decision Support Systems

DTIC Science & Technology

1990-05-23

also provides for decisions which must be made by more than one person [Straub and Beauclair , 1987, pp 1]. 38 With a broad definition of GDSS any tool...Figure 5 represents the definition of GDSS categories used by this study [Straub and Beauclair , 1987]. Alias and DeSanctis & GDSS Name Gallupe type...DeSanctis and Gallupe, 1987]. Straub and Beauclair combined types 2 and 4 into one category. 39 Type 1 is a Decision Room, consisting of a face-to

Anti-proliferation of triple-negative breast cancer cells with physagulide P: ROS/JNK signaling pathway induces apoptosis and autophagic cell death

PubMed Central

Gao, Cai-Yun; Ma, Ting; Zhang, Hao; Zhou, Miao-Miao; Yang, Yan-Wei; Yang, Lei; Kong, Ling-Yi

2017-01-01

Physagulide P (PP), a new natural compound, was isolated from Physalis angulate L. in our laboratory. In this study, we demonstrated that PP potently suppressed cell proliferation by inducing G2/M phase arrest in MDA-MB-231 and MDA-MB-468 cells. Moreover, PP provoked apoptosis by decreasing the mitochondrial membrane potential and elevating the Bax/Bcl-2 protein expression ratio. The caspase inhibitor Z-VAD-FMK partly restore cell viability, suggesting that apoptosis plays as an important role in the anti-proliferative effect of PP. PP-treated cells also underwent autophagy, as evidenced by the formation of autophagosomes and the accumulation of LC3BII. Furthermore, the knockdown of LC3B reduced PP-induced cytotoxicity, indicating that autophagy played an anticancer effect. PP also induced the generation of reactive oxygen species (ROS) and resulted in c-Jun N-terminal kinases (JNK) activation. Accordingly, JNK siRNA significantly attenuated PP-triggered apoptosis and autophagy, and ROS scavengers almost completely reverse this apoptosis and autophagy. The ROS scavenger also blocked PP-induced G2/M phase arrest and the phosphorylation of JNK. Our results revealed that PP induced G2/M phase arrest, apoptosis and autophagy via the ROS/JNK signaling pathway in MDA-MB-231 and MDA-MB-468 cells. Therefore, PP is a promising candidate for the development of antitumor drugs for the treatment of triple-negative breast cancer. PMID:28969050

Predictive MRI correlates of lesser metatarsophalangeal joint plantar plate tear.

PubMed

Umans, Rachel L; Umans, Benjamin D; Umans, Hilary; Elsinger, Elisabeth

2016-07-01

To identify correlated signs on non-enhanced MRI that might improve diagnostic detection of plantar plate (PP) tear. We performed an IRB-approved, HIPAA-compliant retrospective analysis of 100 non-contrast MRI (50 PP tear, 50 controls). All were anonymized, randomized, and reviewed; 20 were duplicated to assess consistency. One musculoskeletal radiologist evaluated qualitative variables. A trained non-physician performed measurements. Consistency and concordance were assessed. Pearson's Chi-square test was used to test the correlation between qualitative findings and PP tear status. Correlation between measurements and PP status was assessed using t tests and Wilcoxon's rank-sum test (p values < 0.05 considered significant). Classification and regression trees were utilized to identify attributes that, taken together, would consistently distinguish PP tear from controls. Quantitative measurements were highly reproducible (concordance 0.88-0.99). Elevated 2nd MT protrusion, lesser MT supination and rotational divergence of >45° between the 1st-2nd MT axis correlated with PP tear. Pericapsular soft tissue thickening correlated most strongly with PP tear, correctly classifying 95 % of cases and controls. Excluding pericapsular soft tissue thickening, sequential assessment of 2nd toe enthesitis, 2nd flexor tendon subluxation, and splaying of the second and third toes accurately classified PP status in 92 %. Pericapsular soft tissue thickening most strongly correlated with PP tear. For cases in which it might be difficult to distinguish pericapsular fibrosis from neuroma, sequential assessment of 2nd toe enthesitis, flexor tendon subluxation and splaying of the 2nd and 3rd toe is most helpful for optimizing accurate diagnosis of PP tear.

Reciprocal regulation of ARPP-16 by PKA and MAST3 kinases provides a cAMP-regulated switch in protein phosphatase 2A inhibition.

PubMed

Musante, Veronica; Li, Lu; Kanyo, Jean; Lam, Tukiet T; Colangelo, Christopher M; Cheng, Shuk Kei; Brody, A Harrison; Greengard, Paul; Le Novère, Nicolas; Nairn, Angus C

2017-06-14

ARPP-16, ARPP-19, and ENSA are inhibitors of protein phosphatase PP2A. ARPP-19 and ENSA phosphorylated by Greatwall kinase inhibit PP2A during mitosis. ARPP-16 is expressed in striatal neurons where basal phosphorylation by MAST3 kinase inhibits PP2A and regulates key components of striatal signaling. The ARPP-16/19 proteins were discovered as substrates for PKA, but the function of PKA phosphorylation is unknown. We find that phosphorylation by PKA or MAST3 mutually suppresses the ability of the other kinase to act on ARPP-16. Phosphorylation by PKA also acts to prevent inhibition of PP2A by ARPP-16 phosphorylated by MAST3. Moreover, PKA phosphorylates MAST3 at multiple sites resulting in its inhibition. Mathematical modeling highlights the role of these three regulatory interactions to create a switch-like response to cAMP. Together, the results suggest a complex antagonistic interplay between the control of ARPP-16 by MAST3 and PKA that creates a mechanism whereby cAMP mediates PP2A disinhibition.

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

Malouli, Daniel; Hansen, Scott G.; Nakayasu, Ernesto S.

The tegument phosphoprotein pp65 (UL83) is the most abundant virion protein in human cytomegalovirus (HCMV). Since pp65 is immunodominant in persistently infected individuals, subunit vaccines against HCMV often include pp65 as T cell stimulatory component. Although HCMV pp65 is non-essential for viral growth in vitro it is thought to have an important role in primary and persistent infection since pp65 displays multiple immunomodulatory functions. To determine whether pp65 is required for infection and to evaluate its role in natural and vaccination-induced immunity we generated a rhesus CMV lacking both homologues, pp65a (Rh111) and pp65b (Rh112). Lack of pp65 resulted inmore » a slight growth defect in vitro and an increase of defective particle formation. However, most pp65-deleted virions in the supernatant were phenotypically normal and proteomics analysis revealed that the ratios of the remaining viral proteins were largely unchanged. RhCMV Δpp65ab was able to persistently infect CMV-negative rhesus macaques (RM) and to super-infect RM previously infected with CMV. To determine whether T cells against pp65 are essential for protection against CMV, we challenged Δpp65ab-infected animals with RhCMV ΔUS2-11, a viral recombinant that lacks inhibitors of MHC-I antigen presentation and is thus unable to overcome CMV-specific T cell immunity. Despite a complete lack of pp65-specific T cells, Δpp65ab protected against ΔUS2-11 challenge suggesting that pp65-specific T cells are not essential for T cell immunity against CMV. Using the same approach we further demonstrate that pp65b-specific T cells, induced by heterologous prime/boost vaccination, are not sufficient to protect against ΔUS2-11 challenge. Our data provides a new approach to test the efficacy of subunit vaccine candidates and suggest that pp65 vaccines are insufficient to induce a T cell response that recapitulates the protective effect of natural infection.« less

Acute toxic responses of the freshwater planarian, Dugesia dorotocephala, to methylmercury

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

Best, J.B.; Morita, M.; Ragin, J.

1981-07-01

Toxic responses of planaria to various aquatic habitat concentrations of methylmercury chloride (MMC) were investigated. One hundred percent lethality occurred within 5 h in 2 ppM MMC, 24 h in 1 ppM MMC, and 5 days in 0.5 ppM MMC. No deaths occurred in 0.2 ppM MMC over a 10 day period, however, non-lethal toxic responses were observed. Varying degrees of head resorption, progressing caudally from the snout were observed. With continuing exposure, partial head regeneration and recovery toward more normal appearance occurred by 10 days. Teratogenic effects were observed in surgical decapitation experiments. Head regeneration was retarded in 0.1more » and 0.2 ppM MMC. Malformations, visible lesions, or gross behavioral abnormalities were produced by 2 week exposure of planaria to concentrations of 20 ppB MMC or lower. (RJC)« less

Structural Basis for Inhibition of Mammalian Adenylyl Cyclase by Calcium

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

Mou, Tung-Chung; Masada, Nanako; Cooper, Dermot M.F.

2009-09-11

Type V and VI mammalian adenylyl cyclases (AC5, AC6) are inhibited by Ca{sup 2+} at both sub- and supramicromolar concentration. This inhibition may provide feedback in situations where cAMP promotes opening of Ca{sup 2+} channels, allowing fine control of cardiac contraction and rhythmicity in cardiac tissue where AC5 and AC6 predominate. Ca{sup 2+} inhibits the soluble AC core composed of the C1 domain of AC5 (VC1) and the C2 domain of AC2 (IIC2). As observed for holo-AC5, inhibition is biphasic, showing 'high-affinity' (K{sub i} = {approx}0.4 {mu}M) and 'low-affinity' (K{sub i} = {approx}100 {mu}M) modes of inhibition. At micromolar concentration,more » Ca{sup 2+} inhibition is nonexclusive with respect to pyrophosphate (PP{sub i}), a noncompetitive inhibitor with respect to ATP, but at >100 {mu}M Ca{sup 2+}, inhibition appears to be exclusive with respect to PP{sub i}. The 3.0 {angstrom} resolution structure of G{alpha}s{center_dot}GTP{gamma}S/forskolin-activated VC1:IIC2 crystals soaked in the presence of ATP{alpha}S and 8 {mu}M free Ca{sup 2+} contains a single, loosely coordinated metal ion. ATP soaked into VC1:IIC2 crystals in the presence of 1.5 mM Ca{sup 2+} is not cyclized, and two calcium ions are observed in the 2.9 {angstrom} resolution structure of the complex. In both of the latter complexes VC1:IIC2 adopts the 'open', catalytically inactive conformation characteristic of the apoenzyme, in contrast to the 'closed', active conformation seen in the presence of ATP analogues and Mg{sup 2+} or Mn{sup 2+}. Structures of the pyrophosphate (PP{sub i}) complex with 10 mM Mg{sup 2+} (2.8 {angstrom}) or 2 mM Ca{sup 2+} (2.7 {angstrom}) also adopt the open conformation, indicating that the closed to open transition occurs after cAMP release. In the latter complexes, Ca{sup 2+} and Mg{sup 2+} bind only to the high-affinity 'B' metal site associated with substrate/product stabilization. Ca{sup 2+} thus stabilizes the inactive conformation in both ATP- and PP{sub i}-bound states.« less

Effect of Weight Training on Self-Concept: A Profile of Those Influenced Most.

ERIC Educational Resources Information Center

Tucker, Larry A.

1983-01-01

A study was conducted to: (1) determine the effect of a four-month weight training program on college males' self-concepts; and (2) identify the types, in terms of extroversion, neuroticism, body cathexis, somatotype, and muscular strength, who benefit most. Training generally favorably affected self-concept. (Author/PP)

Pancreatic Polypeptide Cell Proliferation in the Pancreas and Duodenum Coexisting in a Patient With Pancreatic Adenocarcinoma Treated With a GLP-1 Analog.

PubMed

Talmon, Geoffrey A; Wren, J David; Nguyen, Christophe L; Pour, Parviz M

2017-07-01

A partial pancreaticogastrodudenectomy was performed on a 66-year old man with type 2 diabetes mellitus because of an invasive, moderately differentiated adenocarcinoma in the head of the pancreas. In the adjacent grossly normal tissue of the uncinate process, there was a massive proliferation of pancreatic polypeptide (PP) cells confined to this region and showed invasive pattern. Strikingly, in the heaped area of his duodenum, there was a strikingly large number of PP, glucagon, a few insulin cells in a mini-islet-like patterns composed of glucagon and insulin cells. Among the etiological factors, the possible long-lasting effects of the GLP-1 analog, with which the patient was treated, are discussed. This is the first report in the literature of both the coexistence of a pancreatic adenocarcinoma and invasive PPoma and the occurrence of PP and insulin cells in human duodenal mucosa.

Scanning Fiber Endoscope Improves Detection of 5-Aminolevulinic Acid-Induced Protoporphyrin IX Fluorescence at the Boundary of Infiltrative Glioma.

PubMed

Belykh, Evgenii; Miller, Eric J; Hu, Danying; Martirosyan, Nikolay L; Woolf, Eric C; Scheck, Adrienne C; Byvaltsev, Vadim A; Nakaji, Peter; Nelson, Leonard Y; Seibel, Eric J; Preul, Mark C

2018-05-01

Fluorescence-guided surgery with protoporphyrin IX (PpIX) as a photodiagnostic marker is gaining acceptance for resection of malignant gliomas. Current wide-field imaging technologies do not have sufficient sensitivity to detect low PpIX concentrations. We evaluated a scanning fiber endoscope (SFE) for detection of PpIX fluorescence in gliomas and compared it to an operating microscope (OPMI) equipped with a fluorescence module and to a benchtop confocal laser scanning microscope (CLSM). 5-Aminolevulinic acid-induced PpIX fluorescence was assessed in GL261-Luc2 cells in vitro and in vivo after implantation in mouse brains, at an invading glioma growth stage, simulating residual tumor. Intraoperative fluorescence of high and low PpIX concentrations in normal brain and tumor regions with SFE, OPMI, CLSM, and histopathology were compared. SFE imaging of PpIX correlated to CLSM at the cellular level. PpIX accumulated in normal brain cells but significantly less than in glioma cells. SFE was more sensitive to accumulated PpIX in fluorescent brain areas than OPMI (P < 0.01) and dramatically increased imaging time (>6×) before tumor-to-background contrast was diminished because of photobleaching. SFE provides new endoscopic capabilities to view PpIX-fluorescing tumor regions at cellular resolution. SFE may allow accurate imaging of 5-aminolevulinic acid labeling of gliomas and other tumor types when current detection techniques have failed to provide reliable visualization. SFE was significantly more sensitive than OPMI to low PpIX concentrations, which is relevant to identifying the leading edge or metastasizing cells of malignant glioma or to treating low-grade gliomas. This new application has the potential to benefit surgical outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

A widespread family of serine/threonine protein phosphatases shares a common regulatory switch with proteasomal proteases

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

Bradshaw, Niels; Levdikov, Vladimir M.; Zimanyi, Christina M.

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 activitymore » 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.« less

Differential partitioning and speciation of Hg in wet FGD facilities of two Spanish PCC power plants.

PubMed

Ochoa-González, R; Córdoba, P; Díaz-Somoano, M; Font, O; López-Antón, M A; Leiva, C; Martínez-Tarazona, M R; Querol, X; Pereira, C Fernández; Tomás, A; Gómez, P; Mesado, P

2011-10-01

This paper evaluates the speciation and partitioning of mercury in two Spanish pulverised coal combustion power plants (PP1 and PP2), equipped with wet limestone-based flue gas desulphurisation facilities (FGD) operating with forced oxidation and re-circulation of FGD water streams. These plants are fed with coal (PP1) and coal/pet-coke blends (PP2) with different mercury contents. The behaviour, partitioning and speciation of Hg were found to be similar during the combustion processes but different in the FGD systems of the two power plants. A high proportion (86-88%) of Hg escaped the electrostatic precipitator in gaseous form, Hg2+ being the predominant mercury species (68-86%) to enter the FGD. At this point, a relatively high total Hg retention (72% and 65%) was achieved in the PP1 and PP2 (2007) FGD facilities respectively. However, during the second sampling campaign for PP2 (2008), the mercury removal achieved by the FGD was much lower (26%). Lab-scale tests point to liquid/gas ratio as the main parameter affecting oxidised mercury capture in the scrubber. The partitioning of the gaseous mercury reaching the FGD system in the wastes and by-products differed. In the low mercury input power plant (PP1) most of the mercury (67%) was associated with the FGD gypsum. Moreover in PP2 a significant proportion of the gaseous mercury reaching the FGD system remained in the aqueous phase (45%) in the 2007 sampling campaign while most of it escaped in 2008 (74%). This may be attributed to the scrubber operating conditions and the different composition and chemistry of the scrubber solution probably due to the use of an additive. Copyright © 2011 Elsevier Ltd. All rights reserved.

Protein Phosphatase 2A Signaling in Human Prostate Cancer

DTIC Science & Technology

2014-08-01

transfectants. Later, these cells were characterized for the PP2Acα expression and activity by immunoblot and malachite green based assay, respectively. Data...After centrifugation, 25 mL of supernatant was transferred to an assay plate; 100 mL of Malachite Green phosphate detection solution was added and incu...cancer cells was resolved and immunoblotted for PP2AC and b-actin (internal control). PP2A activity was determined by malachite green–based

Uranium hydrogeochemical and stream sediment reconnaissance of the Durango NTMS quadrangle, Colorado

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

Dawson, H.E.; Weaver, T.A.

1979-01-01

During the spring and summer of 1976, 1518 water and 1604 waterborne sediment samples were collected from 1804 locations in the Durango NTMS quadrangle, Colorado. The samples obtained from this 19 940-km/sup 2/ area were analyzed at the Los Alamos Scientific Laboratory for total uranium. The uranium concentrations in waters ranged from less than the detectable limit of 0.2 ppB to 25.7 ppB, with a mean value of 0.84 ppB. The concentrations in sediments ranged from 1.0 ppM to 71.6 ppM, with a mean value of 4.2 ppM. Study of total water and total sediment populations indicated that both aremore » actually mixtures of several populations. Consequently, samples were chosen for discussion on the basis of their having conspicuously high uranium concentrations relative to surrounding background values. Thirty-four water samples (approximately 2.2% of the total water population) had uranium concentrations above 5.00 ppB, the highest of which were well water samples from the San Luis Valley. Thirty-seven sediment samples (approximately 2.3% of the total sediment population) had uranium concentrations above 12.0 ppM. The majority of these were taken from sites in Precambrian rocks, but several came from Paleozoic and Mesozoic strate and Tertiary volcanics. The uranium concentrations in sediment samples from areas of Precambrian rock were especially high and these areas may warrant further, more detailed investigations.« less

Identification of autism-related MECP2 mutations by whole-exome sequencing and functional validation.

PubMed

Wen, Zhu; Cheng, Tian-Lin; Li, Gai-Zhi; Sun, Shi-Bang; Yu, Shun-Ying; Zhang, Yi; Du, Ya-Song; Qiu, Zilong

2017-01-01

Methyl-CpG-binding protein-2 (MeCP2) is a critical regulator for neural development. Either loss- or gain-of-function leads to severe neurodevelopmental disorders, such as Rett syndrome (RTT) and autism spectrum disorder (ASD). We set out to screen for MECP2 mutations in patients of ASD and determine whether these autism-related mutations may compromise the proper function of MeCP2. Whole-exome sequencing was performed to screen MECP2 and other ASD candidate genes for 120 patients diagnosed with ASD. The parents of patients who were identified with MECP2 mutation were selected for further Sanger sequencing. Each patient accomplished the case report form including general information and clinical scales applied to assess their clinical features. Mouse cortical neurons and HEK-293 cells were cultured and transfected with MeCP2 wild-type (WT) or mutant to examine the function of autism-associated MeCP2 mutants. HEK-293 cells were used to examine the expression of MeCP2 mutant constructs with Western blot. Mouse cortical neurons were used to analyze neurites and axon outgrowth by immunofluorescence experiments. We identified three missense mutations of MECP2 from three autism patients by whole-exome sequencing: p.P152L (c.455C>T), p.P376S (c.1162C>T), and p.R294X (c.880C>T). Among these mutations, p.P152L and p.R294X were de novo mutations, whereas p.P376S was inherited maternally. The diagnosis of RTT was excluded in all three autism patients. Abnormalities of dendritic and axonal growth were found after autism-related MeCP2 mutants were expressed in mouse cortical neurons; suggesting that autism-related MECP2 mutations impair the proper development of neurons. Our study identified genetic mutations of the MECP2 gene in autism patients, which were previously considered to be associated primarily with RTT. This finding suggests that loss-of-function mutations of MECP2 may also lead to autism spectrum disorders.

Structural modelling and transcriptional responses highlight a clade of PpKAI2-LIKE genes as candidate receptors for strigolactones in Physcomitrella patens.

PubMed

Lopez-Obando, Mauricio; Conn, Caitlin E; Hoffmann, Beate; Bythell-Douglas, Rohan; Nelson, David C; Rameau, Catherine; Bonhomme, Sandrine

2016-06-01

A set of PpKAI2 - LIKE paralogs that may encode strigolactone receptors in Physcomitrella patens were identified through evolutionary, structural, and transcriptional analyses, suggesting that strigolactone perception may have evolved independently in basal land plants in a similar manner as spermatophytes. Carotenoid-derived compounds known as strigolactones are a new class of plant hormones that modulate development and interactions with parasitic plants and arbuscular mycorrhizal fungi. The strigolactone receptor protein DWARF14 (D14) belongs to the α/β hydrolase family. D14 is closely related to KARRIKIN INSENSITIVE2 (KAI2), a receptor of smoke-derived germination stimulants called karrikins. Strigolactone and karrikin structures share a butenolide ring that is necessary for bioactivity. Charophyte algae and basal land plants produce strigolactones that influence their development. However phylogenetic studies suggest that D14 is absent from algae, moss, and liverwort genomes, raising the question of how these basal plants perceive strigolactones. Strigolactone perception during seed germination putatively evolved in parasitic plants through gene duplication and neofunctionalization of KAI2 paralogs. The moss Physcomitrella patens shows an increase in KAI2 gene copy number, similar to parasitic plants. In this study we investigated whether P. patens KAI2-LIKE (PpKAI2L) genes may contribute to strigolactone perception. Based on phylogenetic analyses and homology modelling, we predict that a clade of PpKAI2L proteins have enlarged ligand-binding cavities, similar to D14. We observed that some PpKAI2L genes have transcriptional responses to the synthetic strigolactone GR24 racemate or its enantiomers. These responses were influenced by light and dark conditions. Moreover, (+)-GR24 seems to be the active enantiomer that induces the transcriptional responses of PpKAI2L genes. We hypothesize that members of specific PpKAI2L clades are candidate strigolactone receptors in moss.

PP2A inhibition assay using recombinant enzyme for rapid detection of okadaic acid and its analogs in shellfish.

PubMed

Ikehara, Tsuyoshi; Imamura, Shihoko; Yoshino, Atsushi; Yasumoto, Takeshi

2010-01-01

Okadaic acid and its analogs (OAs) responsible for diarrhetic shellfish poisoning (DSP) strongly inhibit protein phosphatase 2A (PP2A) and thus are quantifiable by measuring the extent of the enzyme inhibition. In this study, we evaluated the suitability of the catalytic subunit of recombinant human PP2A (rhPP2Ac) for use in a microplate OA assay. OA, dinophysistoxin-1(DTX1), and hydrolyzate of 7-O-palmitoyl-OA strongly inhibited rhPP2Ac activity with IC(50) values of 0.095, 0.104, and 0.135 nM, respectively. The limits of detection and quantitation for OA in the digestive gland of scallops and mussels were 0.0348 μg/g and 0.0611 μg/g respectively, and, when converted to the whole meat basis, are well below the regulation level proposed by EU (0.16 μg/g whole meat). A good correlation with LC-MS data was demonstrated, the correlation coefficient being 0.996 with the regression slope of 1.097.

Tissue response to collagen containing polypropylene meshes in an ovine vaginal repair model.

PubMed

Darzi, Saeedeh; Urbankova, Iva; Su, Kai; White, Jacinta; Lo, Camden; Alexander, David; Werkmeister, Jerome A; Gargett, Caroline E; Deprest, Jan

2016-07-15

Pelvic Organ Prolapse (POP) is the herniation of pelvic organs into the vagina. Despite broad acceptance of mesh use in POP surgical repair, the complication rate is unacceptable. We hypothesized that collagen-containing polypropylene (PP) mesh types could modulate mesh-tissue integration and reduce long-term inflammation, thereby reducing mesh-associated complications. This study compared the long-term tissue response to an unmodified PP mesh and two collagen containing meshes in an ovine model which has similar pelvic anatomy and vaginal size to human. Three commercially available macroporous PP meshes, uncoated PP mesh (Avaulta Solo) (PP), the same textile PP mesh layered with a sheet of cross-linked porcine acellular matrix (Avaulta Plus) (PP-ACM) and a different yet also macroporous PP (Sofradim) mesh coated with solubilized atelocollagen (Ugytex) (PP-sCOL) were implanted in the ovine vagina and tissue explanted after 60 and 180days. The macrophage phenotype and response to implanted meshes, and vascularity were quantified by immunostaining and morphometry. We quantified changes in extracellular matrix composition biochemically and collagen organisation and percentage area around the interface of the mesh implants by Sirius Red birefringence and morphometry. PP-ACM induced a more sustained inflammatory response, indicated by similar CD45(+) leukocytes but reduced CD163(+) M2 macrophages at 60days (P<0.05). PP-sCOL increased Von Willebrand Factor (vWF)-immunoreactive vessel profiles after 60days. At the micro-molecular level, collagen birefringence quantification revealed significantly fewer mature collagen fibrils (red, thick fibrils) at the mesh-tissue interface than control tissue for all mesh types (P<0.001) but still significantly greater than the proportion of immature (green thin fibrils) at 60days (P<0.05). The proportion of mature collagen fibrils increased with time around the mesh filaments, particularly those containing collagen. The total collagen percent area at the mesh interface was greatest around the PP-ACM mesh at 60days (P<0.05). By 180days the total mature and immature collagen fibres at the interface of the mesh filaments resembled that of native tissue. In particular, these results suggest that both meshes containing collagen evoke different types of tissue responses at different times during the healing response yet both ultimately lead to physiological tissue formation approaching that of normal tissue. Pelvic organ prolapse (POP) is the descent of the pelvic organs to the vagina. POP affects more than 25% of all women and the lifetime risk of undergoing POP surgery is 19%. Although synthetic polypropylene (PP) meshes have improved the outcome of the surgical treatment for POP, there was an unacceptable rate of adverse events including mesh exposure and contracture. It is hypothesized that coating the PP meshes with collagen would provide a protective effect by preventing severe mesh adhesions to the wound, resulting in a better controlled initial inflammatory response, and diminished risk of exposure. In this study we assessed the effect of two collagen-containing PP meshes on the long-term vaginal tissue response using new techniques to quantify these tissue responses. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Piperazines for peptide carboxyl group derivatization: effect of derivatization reagents and properties of peptides on signal enhancement in matrix-assisted laser desorption/ionization mass spectrometry.

PubMed

Qiao, Xiaoqiang; Sun, Liangliang; Chen, Lingfan; Zhou, Yuan; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

2011-03-15

Piperazine-based derivatives, including 1-(2-pyridyl)piperazine (2-PP), 1-(2-pyrimidyl)piperazine (2-PMP), 1-(4-pyridyl)piperazine (4-PP), and 1-(1-methyl-4-piperidinyl)piperazine (M-PP), were used for the derivatization of carboxyl groups on peptides with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 1-hydroxy-7-azabenzotriazole (HOAt) as coupling reagents, and trifluoroacetic acid (TFA) as activator. Taking synthetic peptides RVYVHPI (RI-7) and APGDRIYVHPF (AF-11) as samples, the yields of derivatized peptides by 2-PP, 2-PMP and 4-PP were higher than 94%. The effect of piperazine derivatives on the signals of tryptic digests of α-transferrin and bovine serum albumin (BSA) was investigated, and it was found that peptides derivatized by 2-PP and 2-PMP exhibited obviously improved ionization efficiency. Furthermore, comparison of identified peptides before and after derivatization showed that peptides with low molecular weight (MW) and high pI value were preferably detected after derivatization. In addition, after derivatization with 2-PP and 2-PMP, protein myelin basic protein S, 20 kDa protein, and histone H were confidently identified from the tryptic digests of two fractions of rat brain protein separated by reversed-phase high-performance liquid chromatography (HPLC), indicating the potential application of 2-PP and 2-PMP for the highly sensitive determination of peptides in comprehensive proteome analysis. Copyright © 2011 John Wiley & Sons, Ltd.

Pathologic significance of SET/I2PP2A-mediated PP2A and non-PP2A pathways in polycystic ovary syndrome (PCOS).

PubMed

Jiang, Shi-Wen; Xu, Siliang; Chen, Haibin; Liu, Xiaoqiang; Tang, Zuoqing; Cui, Yugui; Liu, Jiayin

2017-01-01

SET (SE translocation, SET), a constitutive inhibitor of protein phosphatase 2A (PP2A), is a multifunctional oncoprotein involved in DNA replication, histone modification, nucleosome assembly, gene transcription and cell proliferation. It is widely expressed in human tissues including the gonadal system and brain. Intensive studies have shown that overexpressed SET plays an important role in the development of Alzheimer's disease (AD), and may also contribute to the malignant transformation of breast and ovarian cancers. Recent studies indicated that through interaction with PP2A, SET may upregulate androgen biosynthesis and contribute to hyperandrogenism in polycystic ovary syndrome (PCOS) patients. This review article summarizes data concerning the SET expression in ovaries from PCOS and normal women, and analyzes the role/regulatory mechanism of SET for androgen biosynthesis in PCOS, as well as the significance of this action in the development of PCOS. The potential value of SET-triggered pathway as a therapeutic target and the application of anti-SET reagents for treating hyperandrogenism in PCOS patients are also discussed. Copyright © 2016. Published by Elsevier B.V.

Dielectric relaxation of near-percolated carbon nanofiber polypropylene composites

NASA Astrophysics Data System (ADS)

Paleo, A. J.; Zille, A.; Van Hattum, F. W.; Ares-Pernas, A.; Agostinho Moreira, J.

2017-07-01

In this work, the morphological, structural and dielectric analysis of near-percolated polypropylene (PP) composites containing carbon nanofibers (CNF) processing by melt-mixing are investigated. Whereas the morphological analysis shows that CNF exhibit some tendency to agglomerate within the PP matrix, the structural analysis showed first a general decrease in the intensity of the IR bands as a consequence of the interaction between carbon nanofibers and PP matrix and second an increase of the crystallinity degree of the PP/CNF composites when compared to the pure PP. The dielectric analysis demonstrates enhanced dielectric constants (from 2.97 for neat polymer to 9.7 for 1.9 vol% loaded composites at 200 Hz) and low dielectric losses. Furthermore, the dielectric relaxation for composites with concentrations in the vicinity of percolation is evidenced and well described by the generalized polydispersive Cole-Cole model from which the values of static dielectric constant (εs) , high frequency dielectric constant (ε∞) , distribution of relaxation time (α) and mean relaxation time (τo), are determined, suggesting that this latter analysis constitutes a strong tool for understanding the relationships between microstructure and dielectric properties in this type of polymer composites.

Pin1At regulates PIN1 polar localization and root gravitropism.

PubMed

Xi, Wanyan; Gong, Ximing; Yang, Qiaoyun; Yu, Hao; Liou, Yih-Cherng

2016-01-21

Root gravitropism allows plants to establish root systems and its regulation depends on polar auxin transport mediated by PIN-FORMED (PIN) auxin transporters. PINOID (PID) and PROTEIN PHOSPHATASE 2A (PP2A) act antagonistically on reversible phosphorylation of PINs. This regulates polar PIN distribution and auxin transport. Here we show that a peptidyl-prolyl cis/trans isomerase Pin1At regulates root gravitropism. Downregulation of Pin1At suppresses root agravitropic phenotypes of pp2aa and 35S:PID, while overexpression of Pin1At affects root gravitropic responses and enhances the pp2aa agravitropic phenotype. Pin1At also affects auxin transport and polar localization of PIN1 in stele cells, which is mediated by PID and PP2A. Furthermore, Pin1At catalyses the conformational change of the phosphorylated Ser/Thr-Pro motifs of PIN1. Thus, Pin1At mediates the conformational dynamics of PIN1 and affects PID- and PP2A-mediated regulation of PIN1 polar localization, which correlates with the regulation of root gravitropism.

Pin1At regulates PIN1 polar localization and root gravitropism

PubMed Central

Xi, Wanyan; Gong, Ximing; Yang, Qiaoyun; Yu, Hao; Liou, Yih-Cherng

2016-01-01

Root gravitropism allows plants to establish root systems and its regulation depends on polar auxin transport mediated by PIN-FORMED (PIN) auxin transporters. PINOID (PID) and PROTEIN PHOSPHATASE 2A (PP2A) act antagonistically on reversible phosphorylation of PINs. This regulates polar PIN distribution and auxin transport. Here we show that a peptidyl-prolyl cis/trans isomerase Pin1At regulates root gravitropism. Downregulation of Pin1At suppresses root agravitropic phenotypes of pp2aa and 35S:PID, while overexpression of Pin1At affects root gravitropic responses and enhances the pp2aa agravitropic phenotype. Pin1At also affects auxin transport and polar localization of PIN1 in stele cells, which is mediated by PID and PP2A. Furthermore, Pin1At catalyses the conformational change of the phosphorylated Ser/Thr-Pro motifs of PIN1. Thus, Pin1At mediates the conformational dynamics of PIN1 and affects PID- and PP2A-mediated regulation of PIN1 polar localization, which correlates with the regulation of root gravitropism. PMID:26791759

The Compartmentalisation of Phosphorylated Free Oligosaccharides in Cells from a CDG Ig Patient Reveals a Novel ER-to-Cytosol Translocation Process

PubMed Central

Peric, Delphine; Durrant-Arico, Christelle; Delenda, Christophe; Dupré, Thierry; De Lonlay, Pascale; de Baulny, Hélène Ogier; Pelatan, Cécile; Bader-Meunier, Brigitte; Danos, Olivier; Chantret, Isabelle; Moore, Stuart E. H.

2010-01-01

Background Biosynthesis of the dolichol linked oligosaccharide (DLO) required for protein N-glycosylation starts on the cytoplasmic face of the ER to give Man5GlcNAc2-PP-dolichol, which then flips into the ER for further glycosylation yielding mature DLO (Glc3Man9GlcNAc2-PP-dolichol). After transfer of Glc3Man9GlcNAc2 onto protein, dolichol-PP is recycled to dolichol-P and reused for DLO biosynthesis. Because de novo dolichol synthesis is slow, dolichol recycling is rate limiting for protein glycosylation. Immature DLO intermediates may also be recycled by pyrophosphatase-mediated cleavage to yield dolichol-P and phosphorylated oligosaccharides (fOSGN2-P). Here, we examine fOSGN2-P generation in cells from patients with type I Congenital Disorders of Glycosylation (CDG I) in which defects in the dolichol cycle cause accumulation of immature DLO intermediates and protein hypoglycosylation. Methods and Principal Findings In EBV-transformed lymphoblastoid cells from CDG I patients and normal subjects a correlation exists between the quantities of metabolically radiolabeled fOSGN2-P and truncated DLO intermediates only when these two classes of compounds possess 7 or less hexose residues. Larger fOSGN2-P were difficult to detect despite an abundance of more fully mannosylated and glucosylated DLO. When CDG Ig cells, which accumulate Man7GlcNAc2-PP-dolichol, are permeabilised so that vesicular transport and protein synthesis are abolished, the DLO pool required for Man7GlcNAc2-P generation could be depleted by adding exogenous glycosylation acceptor peptide. Under conditions where a glycotripeptide and neutral free oligosaccharides remain predominantly in the lumen of the ER, Man7GlcNAc2-P appears in the cytosol without detectable generation of ER luminal Man7GlcNAc2-P. Conclusions and Significance The DLO pools required for N-glycosylation and fOSGN2-P generation are functionally linked and this substantiates the hypothesis that pyrophosphatase-mediated cleavage of DLO intermediates yields recyclable dolichol-P. The kinetics of cytosolic fOSGN2-P generation from a luminally-generated DLO intermediate demonstrate the presence of a previously undetected ER-to-cytosol translocation process for either fOSGN2-P or DLO. PMID:20652024

Therapeutic potential of a dual mTORC1/2 inhibitor for the prevention of posterior capsule opacification: An in vitro study.

PubMed

Feng, Hao; Yang, Zhibo; Bai, Xue; Yang, Meirong; Fang, Yuan; Zhang, Xiaonan; Guo, Qiqiang; Ning, Hong

2018-04-01

Mammalian target of rapamycin (mTOR) serves a central role in regulating cell growth and survival, and has been demonstrated to be involved in the pathological progression of posterior capsule opacification (PCO). In the present study, the potency of PP242, a novel dual inhibitor of mTOR complex 1/2 (mTORC1/2), in the suppression of the growth of human lens epithelial cells (HLECs) was investigated. Using a Cell Counting Kit‑8 and a wound healing assay, it was demonstrated that PP242 inhibited the proliferation and migration of HLECs. In addition, western blot analysis indicated that PP242 completely inhibited mTORC1 and mTORC2 downstream signaling activities, whereas rapamycin only partially inhibited mTORC1 activity within LECs. Furthermore, PP242 treatment led to an upregulation of the expression levels of p53 and B cell lymphoma‑2 (Bcl‑2)‑associated X and downregulation of Bcl‑2. In addition, flow cytometric analysis demonstrated that PP242 induced the cell cycle arrest at the G0/G1 phase, which may have caused apoptosis and induced autophagy within the LECs. The results of the present study suggested that administration of PP242 may potentially offer a novel therapeutic approach for the prevention of PCO.

Aquatic Plant Control Research Program. Allelopathic Aquatic Plants for Aquatic Plant Management: A Feasibility Study

DTIC Science & Technology

1989-10-01

1978. " Ecotoxicology of aquatic plant communi- ties," Principles of Ecotoxicology , SCOPE Report 12, Chapter 11, pp 239-255. [Heavy metals, Pollutants...Phragmites communis and Equisetum limosum were cultivated . They found plant-plant influences depend on soil type. Typha latifolia, S. A2 lacustris, and

Effect of pancreatic polypeptide on gallbladder pressure and hepatic bile secretion.

PubMed

Adrian, T E; Mitchenere, P; Sagor, G; Bloom, S R

1982-09-01

Intraluminal gallbladder pressure, measured by radiotelemetry, and bile output were monitored during infusion of porcine pancreatic polypeptide (PP) at doses of 6, 25, 100, and 400 pmol . kg-1 . h-1 in healthy conscious pigs. Plasma PP concentrations during infusion of the three lower doses, measured by radioimmunoassay, were within the range seen postprandially in these animals. Gallbladder pressure fell in a dose-related manner during PP infusion by 2.2 +/- 0.9, 8.2 +/- 0.4, 11.6 +/- 0.7, and 14.8 +/- 0.8 mmHg, respectively. In addition, a significant reduction in the bile output was observed during infusion of the two higher doses of PP. In a separate series of experiments, using cholecystectomized pigs, PP had no effect on bile output. These findings suggest that the amount of PP released postprandially may be sufficient to influence gallbladder function but not hepatic secretion of bile in the pig.

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

Schuster, J.J.; Stryker, J.A.; Demers, L.M.

The pathophysiology of chronic radiation-induced diarrhea was evaluated in 28 patients who had undergone pelvic irradiation for gynecologic neoplasms 2 to 7 years previously. Twenty-seven patients undergoing radiotherapy with techniques that did not require abdominal or pelvic irradiation served as controls. The glycine conjugates of cholic acid (GC) were measured in serum by radioimmunoassay. Fasting and 2 hr. pp GC levels for the pelvic irradiated patients were 11.0 +/- 11.1 (mean +/- SD) and 24.8 +/- 17.3 micrograms/dl. Fasting and 2 hr. pp GC levels for controls were 12.6 +/- 7.4 and 28.0 +/- 14.7. There were no significant differencesmore » in the post-prandial increases in serum GC between pelvic irradiated patients and controls (p = .23, Type II error probability = .13). There was also no significant difference in the 2 hr. pp and fasting GC ratio (p = .39). There was significant difference between the stool frequency (p less than .01) and the prevalence of diarrhea (p less than .02) between pelvic irradiated patients and controls. The data suggest that bile acid malabsorption due to ileal dysfunction is not an inevitable late complication of pelvic irradiation and is not the major determinant in the pathophysiology of chronic radiation-induced diarrhea.« less

Three-Dimensional Shallow Water Acoustics

DTIC Science & Technology

2015-09-30

converts the Helmholtz wave equation of elliptic type to a one-way wave equation of parabolic type. The conversion allows efficient marching solution ...algorithms for 2 solving the boundary value problem posed by the Helmholtz equation . This can reduce significantly the requirement for computational...Fourier parabolic- equation sound propagation solution scheme," J. Acoust. Soc. Am, vol. 132, pp. EL61-EL67 (2012). [6] Y.-T. Lin, J.M. Collis and T.F

The Design, Usability, and Feasibility of a Family-Focused Diabetes Self-Care Support mHealth Intervention for Diverse, Low-Income Adults with Type 2 Diabetes.

PubMed

Mayberry, Lindsay Satterwhite; Berg, Cynthia A; Harper, Kryseana J; Osborn, Chandra Y

2016-01-01

Family members' helpful and harmful actions affect adherence to self-care and glycemic control among adults with type 2 diabetes (T2D) and low socioeconomic status. Few family interventions for adults with T2D address harmful actions or use text messages to reach family members. Through user-centered design and iterative usability/feasibility testing, we developed a mHealth intervention for disadvantaged adults with T2D called FAMS. FAMS delivers phone coaching to set self-care goals and improve patient participant's (PP) ability to identify and address family actions that support/impede self-care. PPs receive text message support and can choose to invite a support person (SP) to receive text messages. We recruited 19 adults with T2D from three Federally Qualified Health Centers to use FAMS for two weeks and complete a feedback interview. Coach-reported data captured coaching success, technical data captured user engagement, and PP/SP interviews captured the FAMS experience. PPs were predominantly African American, 83% had incomes <$35,000, and 26% were married. Most SPs ( n = 7) were spouses/partners or adult children. PPs reported FAMS increased self-care and both PPs and SPs reported FAMS improved support for and communication about diabetes. FAMS is usable and feasible and appears to help patients manage self-care support, although some PPs may not have a SP.

The Design, Usability, and Feasibility of a Family-Focused Diabetes Self-Care Support mHealth Intervention for Diverse, Low-Income Adults with Type 2 Diabetes

PubMed Central

Berg, Cynthia A.; Harper, Kryseana J.; Osborn, Chandra Y.

2016-01-01

Family members' helpful and harmful actions affect adherence to self-care and glycemic control among adults with type 2 diabetes (T2D) and low socioeconomic status. Few family interventions for adults with T2D address harmful actions or use text messages to reach family members. Through user-centered design and iterative usability/feasibility testing, we developed a mHealth intervention for disadvantaged adults with T2D called FAMS. FAMS delivers phone coaching to set self-care goals and improve patient participant's (PP) ability to identify and address family actions that support/impede self-care. PPs receive text message support and can choose to invite a support person (SP) to receive text messages. We recruited 19 adults with T2D from three Federally Qualified Health Centers to use FAMS for two weeks and complete a feedback interview. Coach-reported data captured coaching success, technical data captured user engagement, and PP/SP interviews captured the FAMS experience. PPs were predominantly African American, 83% had incomes <$35,000, and 26% were married. Most SPs (n = 7) were spouses/partners or adult children. PPs reported FAMS increased self-care and both PPs and SPs reported FAMS improved support for and communication about diabetes. FAMS is usable and feasible and appears to help patients manage self-care support, although some PPs may not have a SP. PMID:27891524

Maternal and Cord Serum Cytokine Changes with Continuous and Intermittent Labor Epidural Analgesia: A Randomized Study

PubMed Central

Mantha, Venkat R.; Vallejo, Manuel C.; Ramesh, Vimala; Jones, Bobby L.; Ramanathan, Sivam

2012-01-01

Background. Maternal fever during labor epidural analgesia (LEA) may cause increased maternal and cord serum inflammatory cytokines. We report the effects of intermittent and continuous LEA on these cytokines. Methods. Ninety-two women were randomly assigned to continuous (CLEA) or intermittent (ILEA) groups, 46 in each. Maternal temperature was checked and blood drawn at epidural insertion (baseline) and four-hourly until 4 h postpartum (4 PP). Cord blood was drawn after placental delivery. Interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), granulocyte macrophage-colony stimulating factor (GM-CSF), and tumor necrosis factor-α (TNF-α) were measured and analyzed according to group randomization, and then combined and reanalyzed as febrile (temperature ≥38°C) or afebrile groups. Results. Significant intragroup changes from baseline were noted in some groups. Data are pg/mL, median (Q1/Q3). IL-6 rose at all time points in all groups. CLEA: baseline: 18.5 (12.5/31.1), 4 h: 80.0 (46.3/110.8), 8 h: 171.9 (145.3/234.3), and 4 PP: 81 (55.7/137.4). ILEA: baseline: 15.7 (10.2/27.1), 4 h: 68.2 (33.3/95.0), 8 h: 125.0 (86.3/195.0), and 4 PP: 70.2 (54.8/103.6). Febrile group: baseline: 21.6 (13.8/40.9), 4 h: 83.9 (47.5/120.8), 8 h: 186.7 (149.6/349.9), and 4 PP: 105.8 (65.7/158.8). Afebrile group: baseline: 10.9 (2.1/17.4), 4 h: 38.2 (15.0/68.2), 8 h: 93.8 (57.1/135.7), and 4 PP: 52.9 (25.1/78). IL-8 rose at all time points in CLEA: baseline: 2.68 (0.0/4.3), 4 h: 3.7 (0.0/6.5), 8 h: 6.0 (3.3/9.6), 4 PP: 5.6 (0.8/8.0), and afebrile group baseline: 2.5 (0.0/4.7), 4 h: 3.3 (0.0/6.2), 8 h: 5.3 (1.9/9.8), and 4 PP: 4.7 (0.0/7.6). It fell at 4 PP in febrile group: baseline: 4.1 (0.0/6.4), 4 h: 3.8 (0.0/6.5), 8 h: 5.2 (2.5/8.0), and 4 PP: 2.9 (0.0/4.0). GM-CSF increased at 8 h and decreased at 4 PP in ILEA baseline: 2.73 (0.0/7.2), 4 h: 2.73 (0.0/7.9), 8 h: 3.9 (2.7/11.5), and 4 PP: 2.0 (0.0/7.2). It increased at 4 h and 8 h and decreased at 4 PP in febrile group: baseline: 2.6 (0.0/4.2), 4 h: 3.2 (2.1/7.0), 8 h: 4.0 (3.2/12.3), and 4 PP: 2.4 (1.7/12.6). There were no intergroup cytokine changes in maternal or cord serum in CLEA versus ILEA or febrile versus afebrile groups. Conclusions. Some cytokines, especially IL-6, rise physiologically during labor epidural analgesia. PMID:22629160

Development and assessment of an e-learning course on breast imaging for radiographers: a stratified randomized controlled trial.

PubMed

Moreira, Inês C; Ventura, Sandra Rua; Ramos, Isabel; Rodrigues, Pedro Pereira

2015-01-05

Mammography is considered the best imaging technique for breast cancer screening, and the radiographer plays an important role in its performance. Therefore, continuing education is critical to improving the performance of these professionals and thus providing better health care services. Our goal was to develop an e-learning course on breast imaging for radiographers, assessing its efficacy, effectiveness, and user satisfaction. A stratified randomized controlled trial was performed with radiographers and radiology students who already had mammography training, using pre- and post-knowledge tests, and satisfaction questionnaires. The primary outcome was the improvement in test results (percentage of correct answers), using intention-to-treat and per-protocol analysis. A total of 54 participants were assigned to the intervention (20 students plus 34 radiographers) with 53 controls (19+34). The intervention was completed by 40 participants (11+29), with 4 (2+2) discontinued interventions, and 10 (7+3) lost to follow-up. Differences in the primary outcome were found between intervention and control: 21 versus 4 percentage points (pp), P<.001. Stratified analysis showed effect in radiographers (23 pp vs 4 pp; P=.004) but was unclear in students (18 pp vs 5 pp; P=.098). Nonetheless, differences in students' posttest results were found (88% vs 63%; P=.003), which were absent in pretest (63% vs 63%; P=.106). The per-protocol analysis showed a higher effect (26 pp vs 2 pp; P<.001), both in students (25 pp vs 3 pp; P=.004) and radiographers (27 pp vs 2 pp; P<.001). Overall, 85% were satisfied with the course, and 88% considered it successful. This e-learning course is effective, especially for radiographers, which highlights the need for continuing education.

Development and Assessment of an E-Learning Course on Breast Imaging for Radiographers: A Stratified Randomized Controlled Trial

PubMed Central

Ventura, Sandra Rua; Ramos, Isabel; Rodrigues, Pedro Pereira

2015-01-01

Background Mammography is considered the best imaging technique for breast cancer screening, and the radiographer plays an important role in its performance. Therefore, continuing education is critical to improving the performance of these professionals and thus providing better health care services. Objective Our goal was to develop an e-learning course on breast imaging for radiographers, assessing its efficacy, effectiveness, and user satisfaction. Methods A stratified randomized controlled trial was performed with radiographers and radiology students who already had mammography training, using pre- and post-knowledge tests, and satisfaction questionnaires. The primary outcome was the improvement in test results (percentage of correct answers), using intention-to-treat and per-protocol analysis. Results A total of 54 participants were assigned to the intervention (20 students plus 34 radiographers) with 53 controls (19+34). The intervention was completed by 40 participants (11+29), with 4 (2+2) discontinued interventions, and 10 (7+3) lost to follow-up. Differences in the primary outcome were found between intervention and control: 21 versus 4 percentage points (pp), P<.001. Stratified analysis showed effect in radiographers (23 pp vs 4 pp; P=.004) but was unclear in students (18 pp vs 5 pp; P=.098). Nonetheless, differences in students’ posttest results were found (88% vs 63%; P=.003), which were absent in pretest (63% vs 63%; P=.106). The per-protocol analysis showed a higher effect (26 pp vs 2 pp; P<.001), both in students (25 pp vs 3 pp; P=.004) and radiographers (27 pp vs 2 pp; P<.001). Overall, 85% were satisfied with the course, and 88% considered it successful. Conclusions This e-learning course is effective, especially for radiographers, which highlights the need for continuing education. PMID:25560547

Highly sensitive detection and discrimination of LR and YR microcystins based on protein phosphatases and an artificial neural network.

PubMed

Covaci, O I; Sassolas, A; Alonso, G A; Muñoz, R; Radu, G L; Bucur, B; Marty, J-L

2012-08-01

The inhibition characteristics of three different protein phosphatases by three microcystin (MC) variants--LR, YR, and RR--were studied. The corresponding K (I) for each enzyme-MC couple was calculated. The toxicity of MC varies in the following order: MC-LR > MC-YR > MC-RR. The sensitivity of the enzymes increased in the following order: mutant PP2A < mutant PP1 < natural PP2A. The best limit of detection obtained was 21.2 pM MC-LR using the most sensible enzyme. Methanol, ethanol, and acetonitrile up to 2 % (v/v) may be used in inhibition measurements. An artificial neural network (ANN) was used to discriminate two MC variants--LR and YR--using the differences in inhibition percentages measured with mutant PP1 and natural PP2A. The ANN is able to analyze mixtures with concentrations ranging from 8 to 98 pM MC-LR and 31 to 373 pM MC-YR.

Modulation of the endogenous production of protoporphyrin IX in a yeast-based model organism

NASA Astrophysics Data System (ADS)

Joniová, Jaroslava; Gerelli, Emmanuel; Wagnières, Georges

2017-02-01

The main aim of this study was to assess conditions at which simple yeast-based model organism produces maximal levels of protoporphyrin IX (PpIX) after an exogenous administration of its precursor, 5-aminolevulinic acid (ALA), and the ferrous-ion chelator 2,2'-bipyridyl. We observed that the fluorescing porphyrin, produced after these administrations, was likely to be PpIX since fluorescence spectroscopy of the porphyrins produced endogenously in yeast cells resembles that of PpIX in DMSO and in vivo in the chick's chorioallantoic membrane model. Also, fluorescence lifetimes of these porphyrins are very similar to that of PpIX in vitro and in vivo. This suggests that PpIX is the main fluorescent compound produced by yeast in our conditions. We found that the conditions at which yeast produces the maximal PpIX were a synchronous administration of 5 μM ALA and 1 mM 2,2'-bipyridyl for yeast incubated in aqueous glucose and 1 mM 2,2'-bipyridyl in the presence of YPD medium. Such a simple model is of high interest to study basic mechanisms involved in the mitochondrial respiration since PpIX, which is produced in this organelle, can be used as an oxygen sensor, or to perform photodynamic therapy and photodiagnosis. Since the absorption and scattering coefficients of this model are much smaller than those of soft tissues over the visible part of the spectrum, a version of this model loaded with appropriated amounts of light absorbing and scattering particles could be designed as a phantom to mimic tumors containing PpIX, a useful tool to optimize certain cancer photodetection set-ups.

SAV1 promotes Hippo kinase activation through antagonizing the PP2A phosphatase STRIPAK

PubMed Central

Osinski, Adam; Tomchick, Diana R; Brautigam, Chad A

2017-01-01

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. PMID:29063833

SAV1 promotes Hippo kinase activation through antagonizing the PP2A phosphatase STRIPAK

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

Bae, Sung Jun; Ni, Lisheng; Osinski, Adam

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. SAV1more » 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.« less

A PP2A-mediated feedback mechanism controls Ca2+-dependent NO synthesis under physiological oxygen.

PubMed

Keeley, Thomas P; Siow, Richard C M; Jacob, Ron; Mann, Giovanni E

2017-12-01

Intracellular O 2 is a key regulator of NO signaling, yet most in vitro studies are conducted in atmospheric O 2 levels, hyperoxic with respect to the physiologic milieu. We investigated NO signaling in endothelial cells cultured in physiologic (5%) O 2 and stimulated with histamine or shear stress. Culture of cells in 5% O 2 (>5 d) decreased histamine- but not shear stress-stimulated endothelial (e)NOS activity. Unlike cells adapted to a hypoxic environment (1% O 2 ), those cultured in 5% O 2 still mobilized sufficient Ca 2+ to activate AMPK. Enhanced expression and membrane targeting of PP2A-C was observed in 5% O 2 , resulting in greater interaction with eNOS in response to histamine. Moreover, increased dephosphorylation of eNOS in 5% O 2 was Ca 2+ -sensitive and reversed by okadaic acid or PP2A-C siRNA. The present findings establish that Ca 2+ mobilization stimulates both NO synthesis and PP2A-mediated eNOS dephosphorylation, thus constituting a novel negative feedback mechanism regulating eNOS activity not present in response to shear stress. This, coupled with enhanced NO bioavailability, underpins differences in NO signaling induced by inflammatory and physiologic stimuli that are apparent only in physiologic O 2 levels. Furthermore, an explicit delineation between physiologic normoxia and genuine hypoxia is defined here, with implications for our understanding of pathophysiological hypoxia.-Keeley, T. P., Siow, R. C. M., Jacob, R., Mann, G. E. A PP2A-mediated feedback mechanism controls Ca 2+ -dependent NO synthesis under physiological oxygen. © The Author(s).

Interactions between bacterial carbon monoxide and hydrogen consumption and plant development on recent volcanic deposits.

PubMed

King, Gary M; Weber, Carolyn F

2008-02-01

Patterns of microbial colonization and interactions between microbial processes and vascular plants on volcanic deposits have received little attention. Previous reports have shown that atmospheric CO and hydrogen contribute significantly to microbial metabolism on Kilauea volcano (Hawaii) deposits with varied ages and successional development. Relationships between CO oxidation and plant communities were not clear, however, since deposit age and vegetation status covaried. To determine plant-microbe interactions in deposits of uniform ages, CO and hydrogen dynamics have been assayed for unvegetated tephra on a 1959 deposit at Pu'u Puai (PP-bare), at the edge of tree 'islands' within the PP deposit (PP-edge) and within PP tree islands (PP-canopy). Similar assays have been conducted for vegetated and unvegetated sites on a 1969 Mauna Ulu (MU) lava flow. Net in situ atmospheric CO uptake was highest at PP-edge and PP-bare sites (2.2+/-0.5 and 1.3+/-0.1 mg CO m(-2) day(-1), respectively), and least for PP-canopy (-3.2+/-0.9 mg CO m(-2) day(-1), net emission). Respiration rates, microbial biomass and maximum CO uptake potential showed an opposing pattern. Comparisons of atmospheric CO uptake and CO(2) production rates indicate that CO contributes significantly to microbial metabolism in PP-bare and MU-unvegetated sites, but negligibly where vegetation is well developed. Nonetheless, maximum potential CO uptake rates indicate that CO oxidizer populations increase with increasing plant biomass and consume CO actively. Some of these CO oxidizers may contribute to elevated nitrogen fixation rates (acetylene reduction) measured within tree islands, and thus, support plant successional development.

Memantine Attenuates Alzheimer’s Disease-Like Pathology and Cognitive Impairment

PubMed Central

Wang, Xiaochuan; Blanchard, Julie; Iqbal, Khalid

2015-01-01

Deficiency of protein phosphatase-2A is a key event in Alzheimer’s disease. An endogenous inhibitor of protein phosphatase-2A, inhibitor-1, I1 PP2A, which inhibits the phosphatase activity by interacting with its catalytic subunit protein phosphatase-2Ac, is known to be upregulated in Alzheimer’s disease brain. In the present study, we overexpressed I1 PP2A by intracerebroventricular injection with adeno-associated virus vector-1-I1 PP2A in Wistar rats. The I1 PP2A rats showed a decrease in brain protein phosphatase-2A activity, abnormal hyperphosphorylation of tau, neurodegeneration, an increase in the level of activated glycogen synthase kinase-3beta, enhanced expression of intraneuronal amyloid-beta and spatial reference memory deficit; littermates treated identically but with vector only, i.e., adeno-associated virus vector-1-enhanced GFP, served as a control. Treatment with memantine, a noncompetitive NMDA receptor antagonist which is an approved drug for treatment of Alzheimer’s disease, rescued protein phosphatase-2A activity by decreasing its demethylation at Leu309 selectively and attenuated Alzheimer’s disease-like pathology and cognitive impairment in adeno-associated virus vector-1-I1 PP2A rats. These findings provide new clues into the possible mechanism of the beneficial therapeutic effect of memantine in Alzheimer’s disease patients. PMID:26697860

Three Pseudomonas putida FNR Family Proteins with Different Sensitivities to O2.

PubMed

Ibrahim, Susan A; Crack, Jason C; Rolfe, Matthew D; Borrero-de Acuña, José Manuel; Thomson, Andrew J; Le Brun, Nick E; Schobert, Max; Stapleton, Melanie R; Green, Jeffrey

2015-07-03

The Escherichia coli fumarate-nitrate reduction regulator (FNR) protein is the paradigm for bacterial O2-sensing transcription factors. However, unlike E. coli, some bacterial species possess multiple FNR proteins that presumably have evolved to fulfill distinct roles. Here, three FNR proteins (ANR, PP_3233, and PP_3287) from a single bacterial species, Pseudomonas putida KT2440, have been analyzed. Under anaerobic conditions, all three proteins had spectral properties resembling those of [4Fe-4S] proteins. The reactivity of the ANR [4Fe-4S] cluster with O2 was similar to that of E. coli FNR, and during conversion to the apo-protein, via a [2Fe-2S] intermediate, cluster sulfur was retained. Like ANR, reconstituted PP_3233 and PP_3287 were converted to [2Fe-2S] forms when exposed to O2, but their [4Fe-4S] clusters reacted more slowly. Transcription from an FNR-dependent promoter with a consensus FNR-binding site in P. putida and E. coli strains expressing only one FNR protein was consistent with the in vitro responses to O2. Taken together, the experimental results suggest that the local environments of the iron-sulfur clusters in the different P. putida FNR proteins influence their reactivity with O2, such that ANR resembles E. coli FNR and is highly responsive to low concentrations of O2, whereas PP_3233 and PP_3287 have evolved to be less sensitive to O2. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Physalis peruviana L. inhibits airway inflammation induced by cigarette smoke and lipopolysaccharide through inhibition of extracellular signal-regulated kinase and induction of heme oxygenase-1.

PubMed

Park, Hyun Ah; Lee, Jae-Won; Kwon, Ok-Kyoung; Lee, Gilhye; Lim, Yourim; Kim, Jung Hee; Paik, Jin-Hyub; Choi, Sangho; Paryanto, Imam; Yuniato, Prasetyawan; Kim, Doo-Young; Ryu, Hyung Won; Oh, Sei-Ryang; Lee, Seung Jin; Ahn, Kyung-Seop

2017-11-01

Physalis peruviana L. (PP) is a medicinal herb that has been confirmed to have several biological activities, including anticancer, antioxidant and anti-inflammatory properties. The aim of the present study was to evaluate the protective effect of PP on cigarette smoke (CS)- and lipopolysaccharide (LPS)-induced pulmonary inflammation. Treatment with PP significantly reduced the influx of inflammatory cells in the bronchoalveolar lavage fluid (BALF) and lung of mice with CS- and LPS-induced pulmonary inflammation. PP also decreased the levels of reactive oxygen species (ROS) and pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the BALF. PP effectively attenuated the expression of monocyte chemoattractant protein-1 (MCP-1) and the activation of extracellular signal-regulated kinase (ERK) in the lung. In addition, nuclear factor erythroid 2-related factor 2 (Nrf2) activation and heme oxygenase-1 (HO-1) expression were increased by PP treatment. In an in vitro experiment, PP reduced the mRNA expression of TNF-α and MCP-1, and the activation of ERK in CS extract-stimulated A549 epithelial cells. Furthermore, PP increased the activation of Nrf2 and the expression of HO-1 in A549 cells. These findings suggest that PP has a therapeutic potential for the treatment of pulmonary inflammatory diseases, such as chronic obstructive pulmonary disease.

Spacelift: Search for a National Vision

DTIC Science & Technology

1997-04-30

presented to the Thirty- Third Space Congress, April 1996, pp. 2-17. 57 Ibid., pp. 2-17. 58 Ibid., pp. 2-17. 59 David Tamir, F. Lee...Tillotson and Edward L. Ellegood, “21st Century Space Commerce Taking-off from ’Aerospaceports,"’ A technical paper presented to the Thirty- Third Space Congress...The Analytic Hierarchy Process." A paper for Canaveral Council of Technical Societies -Thirty- Third Space Congress. Not dated. "Industrial

Tributyltin induces a G2/M cell cycle arrest in human amniotic cells via PP2A inhibition-mediated inactivation of the ERK1/2 cascades.

PubMed

Zhang, Yali; Guo, Zonglou; Xu, Lihong

2014-03-01

The molecular mechanisms underlying the cell cycle alterations induced by tributyltin (TBT), a highly toxic environmental contaminant, remain elusive. In this study, cell cycle progression and some key regulators in G2/M phase were investigated in human amniotic cells treated with TBT. Furthermore, protein phosphatase (PP) 2A and the ERK cascades were examined. The results showed that TBT caused a G2/M cell cycle arrest that was accompanied by a decrease in the total cdc25C protein level and an increase in the p-cdc2 level in the nucleus. TBT caused a decrease in PP2A activity and inhibited the ERK cascade by inactivating Raf-1, resulting in the dephosphorylation of MEK1/2, ERK1/2, and c-Myc. Taken together, TBT leads to a G2/M cell cycle arrest in FL cells, an increase in p-cdc2 and a decrease in the levels of total cdc25C protein, which may be caused by the PP2A inhibition-mediated inactivation of the ERK1/2 cascades. Copyright © 2014 Elsevier B.V. All rights reserved.

Ventilatory responses to dynamic exercise elicited by intramuscular sensors

NASA Technical Reports Server (NTRS)

Smith, S. A.; Gallagher, K. M.; Norton, K. H.; Querry, R. G.; Welch-O'Connor, R. M.; Raven, P. B.

1999-01-01

PURPOSE: Eight subjects, aged 27.0+/-1.6 yr, performed incremental workload cycling to investigate the contribution of skeletal muscle mechano- and metaboreceptors to ventilatory control during dynamic exercise. METHODS: Each subject performed four bouts of exercise: exercise with no intervention (CON); exercise with bilateral thigh cuffs inflated to 90 mm Hg (CUFF); exercise with application of lower-body positive pressure (LBPP) to 45 torr (PP); and exercise with 90 mm Hg thigh cuff inflation and 45 torr LBPP (CUFF+PP). Ventilatory responses and pulmonary gas exchange variables were collected breath-by-breath with concomitant measurement of leg intramuscular pressure. RESULTS: Ventilation (VE) was significantly elevated from CON during PP and CUFF+PP at workloads corresponding to > or = 60% CON peak oxygen uptake (VO2peak) and during CUFF at workloads > or = 80% CON VO2peak, P < 0.05. The VO2 at which ventilatory threshold occurred was significantly reduced from CON (2.17+/-0.28 L x min(-1)) to 1.60+/-0.19 L x min(-1), 1.45+/-0.15 L x min(-1), and 1.15+/-0.11 L x min(-1) during CUFF, PP, and CUFF+PP, respectively. The slope of the linear regression describing the VE/CO2 output relationship was increased from CON by approximately 22% during CUFF, 40% during PP, and 41% during CUFF+PP. CONCLUSIONS: As intramuscular pressure was significantly elevated immediately upon application of LBPP during PP and CUFF+PP without a concomitant increase in VE, it seems unlikely that LBPP-induced increases in VE can be attributed to activation of the mechanoreflex. These findings suggest that LBPP-induced reductions in perfusion pressure and decreases in venous outflow resulting from inflation of bilateral thigh cuffs may generate a metabolite sensitive intramuscular ventilatory stimulus.

Impacts of dietary calcium, phytate, and nonphytate phosphorus concentrations in the presence or absence of phytase on inositol hexakisphosphate (IP6) degradation in different segments of broilers digestive tract

PubMed Central

Li, W.; Angel, R.; Kim, S.-W.; Brady, K.; Yu, S.; Plumstead, P. W.

2016-01-01

A total of 1,440 straight-run Heritage 56M × fast-feathering Cobb 500F broiler birds were fed from 11 to 13 d of age to determine the impacts of calcium (Ca), phytate phosphorus (PP), nonphytate P (nPP) and phytase concentrations on the myo-inositol hexakisphosphate (IP6) flow through the different parts of gastrointestinal tract (GIT). The experiment was a 2×2×2×3 randomized block design with 2 Ca (0.7 and 1.0%), 2 PP (0.23 and 0.34%), 2 nPP (0.28 and 0.45%) and 3 phytase (0-, 500-, and 1,000-phytase unit (FTU)/kg) concentrations. The experiment was replicated twice (block) with 3 replicates per treatment (Trt) of 10 birds per block. Concentration of IP6 in crop, proventriculus (Prov) plus (+) gizzard (Giz) and distal ileum digesta as well as the ileal IP6 disappearance was determined at 13 d of age. In crop, higher IP6 concentration was seen with increased Ca (P < 0.05). Despite the interaction between PP and phytase, higher dietary PP led to greater IP6 concentration (P < 0.05). Similar main effects of PP and phytase were also seen in Prov+Giz and ileum (P < 0.05) without interactions. Interaction between Ca and nPP on IP6 concentration was seen in Prov+Giz (P < 0.05). Decreased ileal IP6 disappearance was found at higher Ca (62.3% at 0.7% Ca vs. 57.5% at 1.0% Ca; P < 0.05). In general, adding phytase improved IP6 degradation but the degree of impact was dependent on nPP and PP (P < 0.05). In conclusion, phytase inclusion significantly reduced IP6 concentration and IP6 disappearance in distal ileum regardless of GIT segments or diet composition, but impacts of dietary Ca, nPP, and PP differed depending on GIT segment examined. PMID:26740131

The M Phase Kinase Greatwall (Gwl) Promotes Inactivation of PP2A/B55δ, a Phosphatase Directed Against CDK Phosphosites

PubMed Central

Castilho, Priscila V.; Williams, Byron C.; Mochida, Satoru; Zhao, Yong

2009-01-01

We have previously shown that Greatwall kinase (Gwl) is required for M phase entry and maintenance in Xenopus egg extracts. Here, we demonstrate that Gwl plays a crucial role in a novel biochemical pathway that inactivates, specifically during M phase, “antimitotic” phosphatases directed against phosphorylations catalyzed by cyclin-dependent kinases (CDKs). A major component of this phosphatase activity is heterotrimeric PP2A containing the B55δ regulatory subunit. Gwl is activated during M phase by Cdk1/cyclin B (MPF), but once activated, Gwl promotes PP2A/B55δ inhibition with no further requirement for MPF. In the absence of Gwl, PP2A/B55δ remains active even when MPF levels are high. The removal of PP2A/B55δ corrects the inability of Gwl-depleted extracts to enter M phase. These findings support the hypothesis that M phase requires not only high levels of MPF function, but also the suppression, through a Gwl-dependent mechanism, of phosphatase(s) that would otherwise remove MPF-driven phosphorylations. PMID:19793917

Regulation of protein phosphatase 2A during embryonic diapause process in the silkworm, Bombyx mori.

PubMed

Gu, Shi-Hong; Hsieh, Hsiao-Yen; Lin, Pei-Ling

2017-11-01

Regulation of protein phosphorylation requires coordinated interactions between protein kinases and protein phosphatases. In the present study, we investigated regulation of protein phosphatase 2A (PP2A) during the embryonic diapause process of B. mori. An immunoblotting analysis showed that Bombyx eggs contained a catalytic C subunit, a major regulatory B subunit (B55/PR55 subunit), and a structural A subunit, with the A and B subunits undergoing differential changes between diapause and non-diapause eggs during embryonic process. In non-diapause eggs, eggs whose diapause initiation was prevented by HCl, and eggs in which diapause had been terminated by chilling of diapausing eggs at 5°C for 70days and then were transferred to 25°C, protein levels of the A and B subunits of PP2A gradually increased toward embryonic development. However, protein levels of the A and B subunits in diapause eggs remained at low levels during the first 8days after oviposition. The direct determination of PP2A enzymatic activity showed that the activity remained at low levels in diapause eggs during the first 8days after oviposition. However, in non-diapause eggs, eggs whose diapause initiation was prevented by HCl, and eggs in which diapause had been terminated by chilling, PP2A enzymatic activity sharply increased during the first several days, reached a peak during the middle embryonic development, and then greatly decreased 3 or 4days before hatching. Examination of temporal changes in mRNA expression levels of the catalytic β subunit and regulatory subunit of PP2A showed high levels in eggs whose diapause initiation was prevented by HCl compared to those in diapause eggs. These results demonstrate that the higher PP2A gene expression and PP2A A and B subunit protein levels and increased enzymatic activity are related to embryonic development of B. mori. Copyright © 2017 Elsevier Ltd. All rights reserved.

Iron Bioavailability from Ferric Pyrophosphate in Extruded Rice Cofortified with Zinc Sulfate Is Greater than When Cofortified with Zinc Oxide in a Human Stable Isotope Study.

PubMed

Hackl, Laura; Zimmermann, Michael B; Zeder, Christophe; Parker, Megan; Johns, Paul W; Hurrell, Richard F; Moretti, Diego

2017-03-01

Background: Extruded rice grains are often cofortified with iron and zinc. However, it is uncertain if the addition of zinc to iron-fortified rice affects iron absorption and whether this is zinc-compound specific. Objective: We investigated whether zinc, added as zinc oxide (ZnO) or zinc sulfate (ZnSO 4 ), affects human iron absorption from extruded rice fortified with ferric pyrophosphate (FePP). Methods: In 19 iron-depleted Swiss women (plasma ferritin ≤16.5 μ/L) aged between 20 and 39 y with a normal body mass index (in kg/m 2 ; 18.7-24.8), we compared iron absorption from 4 meals containing fortified extruded rice with 4 mg Fe and 3 mg Zn. Three of the meals contained extruded rice labeled with FePP ( 57 FePP): 1 ) 1 meal without added zinc ( 57 FePP-Zn), 2 ) 1 cofortified with ZnO ( 57 FePP+ZnO), and 3 ) 1 cofortified with ZnSO 4 ( 57 FePP+ZnSO 4 ). The fourth meal contained extruded rice without iron or zinc, extrinsically labeled with ferrous sulfate ( 58 FeSO 4 ) added as a solution after cooking. All 4 meals contained citric acid. Iron bioavailability was measured by isotopic iron ratios in red blood cells. We also measured relative in vitro iron solubility from 57 FePP-Zn, 57 FePP+ZnO, and 57 FePP+ZnSO 4 expressed as a fraction of FeSO 4 solubility. Results: Geometric mean fractional iron absorption (95% CI) from 57 FePP+ZnSO 4 was 4.5% (3.4%, 5.8%) and differed from 57 FePP+ZnO (2.7%; 1.8%, 4.1%) ( P < 0.03); both did not differ from 57 FePP-Zn: 4.0% (2.8%, 5.6%). Relative iron bioavailabilities compared with 58 FeSO 4 were 62%, 57%, and 38% from 57 FePP+ZnSO 4 , 57 FePP-Zn, and 57 FePP+ZnO, respectively. In vitro solubility from 57 FePP+ZnSO 4 differed from that of 57 FePP-Zn (14.3%; P < 0.02) but not from that of 57 FePP+ZnO (10.2% compared with 13.1%; P = 0.08). Conclusions: In iron-depleted women, iron absorption from FePP-fortified extruded rice cofortified with ZnSO 4 was 1.6-fold (95% CI: 1.4-, 1.9-fold) that of rice cofortified with ZnO. These findings suggest that ZnSO 4 may be the preferable zinc cofortificant for optimal iron bioavailability of iron-fortified extruded rice. This trial was registered at clinicaltrials.gov as NCT02255942. © 2017 American Society for Nutrition.

Distinctive effects of eicosapentaenoic and docosahexaenoic acids in regulating neural stem cell fate are mediated via endocannabinoid signalling pathways.

PubMed

Dyall, S C; Mandhair, H K; Fincham, R E A; Kerr, D M; Roche, M; Molina-Holgado, F

2016-08-01

Emerging evidence suggests a complex interplay between the endocannabinoid system, omega-3 fatty acids and the immune system in the promotion of brain self-repair. However, it is unknown if all omega-3 fatty acids elicit similar effects on adult neurogenesis and if such effects are mediated or regulated by interactions with the endocannabinoid system. This study investigated the effects of DHA and EPA on neural stem cell (NSC) fate and the role of the endocannabinoid signalling pathways in these effects. EPA, but not DHA, significantly increased proliferation of NSCs compared to controls, an effect associated with enhanced levels of the endocannabinoid 2-arachidonylglycerol (2-AG) and p-p38 MAPK, effects attenuated by pre-treatment with CB1 (AM251) or CB2 (AM630) receptor antagonists. Furthermore, in NSCs derived from IL-1β deficient mice, EPA significantly decreased proliferation and p-p38 MAPK levels compared to controls, suggesting a key role for IL-1β signalling in the effects observed. Although DHA similarly increased 2-AG levels in wild-type NSCs, there was no concomitant increase in proliferation or p-p38 MAPK activity. In addition, in NSCs from IL-1β deficient mice, DHA significantly increased proliferation without effects on p-P38 MAPK, suggesting effects of DHA are mediated via alternative signalling pathways. These results provide crucial new insights into the divergent effects of EPA and DHA in regulating NSC proliferation and the pathways involved, and highlight the therapeutic potential of their interplay with endocannabinoid signalling in brain repair. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reciprocal regulation of ARPP-16 by PKA and MAST3 kinases provides a cAMP-regulated switch in protein phosphatase 2A inhibition

PubMed Central

Musante, Veronica; Li, Lu; Kanyo, Jean; Lam, Tukiet T; Colangelo, Christopher M; Cheng, Shuk Kei; Brody, A Harrison; Greengard, Paul; Le Novère, Nicolas; Nairn, Angus C

2017-01-01

ARPP-16, ARPP-19, and ENSA are inhibitors of protein phosphatase PP2A. ARPP-19 and ENSA phosphorylated by Greatwall kinase inhibit PP2A during mitosis. ARPP-16 is expressed in striatal neurons where basal phosphorylation by MAST3 kinase inhibits PP2A and regulates key components of striatal signaling. The ARPP-16/19 proteins were discovered as substrates for PKA, but the function of PKA phosphorylation is unknown. We find that phosphorylation by PKA or MAST3 mutually suppresses the ability of the other kinase to act on ARPP-16. Phosphorylation by PKA also acts to prevent inhibition of PP2A by ARPP-16 phosphorylated by MAST3. Moreover, PKA phosphorylates MAST3 at multiple sites resulting in its inhibition. Mathematical modeling highlights the role of these three regulatory interactions to create a switch-like response to cAMP. Together, the results suggest a complex antagonistic interplay between the control of ARPP-16 by MAST3 and PKA that creates a mechanism whereby cAMP mediates PP2A disinhibition. DOI: http://dx.doi.org/10.7554/eLife.24998.001 PMID:28613156

The Tea4-PP1 landmark promotes local growth by dual Cdc42 GEF recruitment and GAP exclusion.

PubMed

Kokkoris, Kyriakos; Gallo Castro, Daniela; Martin, Sophie G

2014-05-01

Cell polarization relies on small GTPases, such as Cdc42, which can break symmetry through self-organizing principles, and landmarks that define the axis of polarity. In fission yeast, microtubules deliver the Tea1-Tea4 complex to mark cell poles for growth, but how this complex activates Cdc42 is unknown. Here, we show that ectopic targeting of Tea4 to cell sides promotes the local activation of Cdc42 and cell growth. This activity requires that Tea4 binds the type I phosphatase (PP1) catalytic subunit Dis2 or Sds21, and ectopic targeting of either catalytic subunit is similarly instructive for growth. The Cdc42 guanine-nucleotide-exchange factor Gef1 and the GTPase-activating protein Rga4 are required for Tea4-PP1-dependent ectopic growth. Gef1 is recruited to ectopic Tea4 and Dis2 locations to promote Cdc42 activation. By contrast, Rga4 is locally excluded by Tea4, and its forced colocalization with Tea4 blocks ectopic growth, indicating that Rga4 must be present, but at sites distinct from Tea4. Thus, a Tea4-PP1 landmark promotes local Cdc42 activation and growth both through Cdc42 GEF recruitment and by creating a local trough in a Cdc42 GAP.

Polypharmacy and Unplanned Hospitalizations in Patients with Rheumatoid Arthritis.

PubMed

Filkova, Maria; Carvalho, João; Norton, Sam; Scott, David; Mant, Tim; Molokhia, Mariam; Cope, Andrew; Galloway, James

2017-12-01

Polypharmacy (PP), the prescribing of multiple drugs for an individual, is rising in prevalence. PP associates with an increased risk of adverse drug reactions (ADR) and hospital admissions. We investigated the relationship between PP, characteristics of rheumatoid arthritis (RA), and the risk of unplanned hospital admissions. Patients from a hospital RA cohort were retrospectively analyzed. Information was collected from electronic medical records. Cox proportional hazards were used to compare hospitalization risk according to levels of PP. Admissions were adjudicated to determine whether an ADR was implicated. The study included 1101 patients; the mean number of all medications was 5. PP correlated with increasing age, disease duration, disease activity, and disability. At least 1 unplanned admission occurred for 16% of patients. Patients taking ≥ 10 medications had an adjusted HR for hospitalization of 3.1 (95% CI 2.1-4.5), compared to those taking 0-5 medications. Corticosteroid use associated with a doubling in adjusted risk of admission of 1.7 (95% CI 1.2-2.4). The most common reason for hospitalization was infection (28%). While in half of all admissions an ADR was a possible contributing factor, only 2% of admissions were found to directly result from an ADR. PP is common in RA and is a prognostic marker associated with increased risk of acute hospitalizations. Our data suggest that PP may be an indicator of comorbidity burden rather than a contributing cause of a drug-related toxicity. PP should be monitored to minimize inappropriate combination of prescribed medications. PP may be a useful predictor of clinical outcomes in epidemiologic studies.

Anti-inflammatory effect of a selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor via the stimulation of heme oxygenase-1 in LPS-activated mice and J774.1 murine macrophages.

PubMed

Park, Sung Bum; Park, Ji Seon; Jung, Won Hoon; Kim, Hee Youn; Kwak, Hyun Jung; Ahn, Jin Hee; Choi, Kyoung-Jin; Na, Yoon-Ju; Choi, Sunhwa; Dal Rhee, Sang; Kim, Ki Young

2016-08-01

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts inactive cortisone to the active cortisol. 11β-HSD1 may be involved in the resolution of inflammation. In the present study, we investigate the anti-inflammatory effects of 2-(3-benzoyl)-4-hydroxy-1,1-dioxo-2H-1,2-benzothiazine-2-yl-1-phenylethanone (KR-66344), a selective 11β-HSD1 inhibitor, in lipopolysaccharide (LPS)-activated C57BL/6J mice and macrophages. LPS increased 11β-HSD1 activity and expression in macrophages, which was inhibited by KR-66344. In addition, KR-66344 increased survival rate in LPS treated C57BL/6J mice. HO-1 mRNA expression level was increased by KR-66344, and this effect was reversed by the HO competitive inhibitor, ZnPP, in macrophages. Moreover, ZnPP reversed the suppression of ROS formation and cell death induced by KR-66344. ZnPP also suppressed animal survival rate in LPS plus KR-66344 treated C57BL/6J mice. In the spleen of LPS-treated mice, KR-66344 prevented cell death via suppression of inflammation, followed by inhibition of ROS, iNOS and COX-2 expression. Furthermore, LPS increased NFκB-p65 and MAPK phosphorylation, and these effects were abolished by pretreatment with KR-66344. Taken together, KR-66344 protects against LPS-induced animal death and spleen injury by inhibition of inflammation via induction of HO-1 and inhibition of 11β-HSD1 activity. Thus, we concluded that the selective 11β-HSD1 inhibitor may provide a novel strategy in the prevention/treatment of inflammatory disorders in patients. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

The geographical distribution and prevalence of Echinococcus multilocularis in animals in the European Union and adjacent countries: a systematic review and meta-analysis.

PubMed

Oksanen, Antti; Siles-Lucas, Mar; Karamon, Jacek; Possenti, Alessia; Conraths, Franz J; Romig, Thomas; Wysocki, Patrick; Mannocci, Alice; Mipatrini, Daniele; La Torre, Giuseppe; Boufana, Belgees; Casulli, Adriano

2016-09-28

This study aimed to provide a systematic review on the geographical distribution of Echinococcus multilocularis in definitive and intermediate hosts in the European Union (EU) and adjacent countries (AC). The relative importance of the different host species in the life-cycle of this parasite was highlighted and gaps in our knowledge regarding these hosts were identified. Six databases were searched for primary research studies published from 1900 to 2015. From a total of 2,805 identified scientific papers, 244 publications were used for meta-analyses. Studies in 21 countries reported the presence of E. multilocularis in red foxes, with the following pooled prevalence (PP): low (≤ 1 %; Denmark, Slovenia and Sweden); medium (> 1 % to < 10 %; Austria, Belgium, Croatia, Hungary, Italy, the Netherlands, Romania and the Ukraine); and high (> 10 %; Czech Republic, Estonia, France, Germany, Latvia, Lithuania, Poland, Slovakia, Liechtenstein and Switzerland). Studies from Finland, Ireland, the United Kingdom and Norway reported the absence of E. multilocularis in red foxes. However, E. multilocularis was detected in Arctic foxes from the Arctic Archipelago of Svalbard in Norway. Raccoon dogs (PP 2.2 %), golden jackals (PP 4.7 %) and wolves (PP 1.4 %) showed a higher E. multilocularis PP than dogs (PP 0.3 %) and cats (PP 0.5 %). High E. multilocularis PP in raccoon dogs and golden jackals correlated with high PP in foxes. For intermediate hosts (IHs), muskrats (PP 4.2 %) and arvicolids (PP 6.0 %) showed similar E. multilocularis PP as sylvatic definitive hosts (DHs), excluding foxes. Nutrias (PP 1.0 %) and murids (PP 1.1 %) could play a role in the life-cycle of E. multilocularis in areas with medium to high PP in red foxes. In areas with low PP in foxes, no other DH was found infected with E. multilocularis. When fox E. multilocularis PP was >3 %, raccoon dogs and golden jackals could play a similar role as foxes. In areas with high E. multilocularis fox PP, the wolf emerged as a potentially important DH. Dogs and cats could be irrelevant in the life-cycle of the parasite in Europe, although dogs could be important for parasite introduction into non-endemic areas. Muskrats and arvicolids are important IHs. Swine, insectivores, murids and nutrias seem to play a minor or no role in the life-cycle of the parasite within the EU and ACs.

Evaluation of pump pulsation in respirable size-selective sampling: Part III. Investigation of European standard methods.

PubMed

Soo, Jhy-Charm; Lee, Eun Gyung; Lee, Larry A; Kashon, Michael L; Harper, Martin

2014-10-01

Lee et al. (Evaluation of pump pulsation in respirable size-selective sampling: part I. Pulsation measurements. Ann Occup Hyg 2014a;58:60-73) introduced an approach to measure pump pulsation (PP) using a real-world sampling train, while the European Standards (EN) (EN 1232-1997 and EN 12919-1999) suggest measuring PP using a resistor in place of the sampler. The goal of this study is to characterize PP according to both EN methods and to determine the relationship of PP between the published method (Lee et al., 2014a) and the EN methods. Additional test parameters were investigated to determine whether the test conditions suggested by the EN methods were appropriate for measuring pulsations. Experiments were conducted using a factorial combination of personal sampling pumps (six medium- and two high-volumetric flow rate pumps), back pressures (six medium- and seven high-flow rate pumps), resistors (two types), tubing lengths between a pump and resistor (60 and 90 cm), and different flow rates (2 and 2.5 l min(-1) for the medium- and 4.4, 10, and 11.2 l min(-1) for the high-flow rate pumps). The selection of sampling pumps and the ranges of back pressure were based on measurements obtained in the previous study (Lee et al., 2014a). Among six medium-flow rate pumps, only the Gilian5000 and the Apex IS conformed to the 10% criterion specified in EN 1232-1997. Although the AirChek XR5000 exceeded the 10% limit, the average PP (10.9%) was close to the criterion. One high-flow rate pump, the Legacy (PP=8.1%), conformed to the 10% criterion in EN 12919-1999, while the Elite12 did not (PP=18.3%). Conducting supplemental tests with additional test parameters beyond those used in the two subject EN standards did not strengthen the characterization of PPs. For the selected test conditions, a linear regression model [PPEN=0.014+0.375×PPNIOSH (adjusted R2=0.871)] was developed to determine the PP relationship between the published method (Lee et al., 2014a) and the EN methods. The 25% PP criterion recommended by Lee et al. (2014a), average value derived from repetitive measurements, corresponds to 11% PPEN. The 10% pass/fail criterion in the EN Standards is not based on extensive laboratory evaluation and would unreasonably exclude at least one pump (i.e. AirChek XR5000 in this study) and, therefore, the more accurate criterion of average 11% from repetitive measurements should be substituted. This study suggests that users can measure PP using either a real-world sampling train or a resistor setup and obtain equivalent findings by applying the model herein derived. The findings of this study will be delivered to the consensus committees to be considered when those standards, including the EN 1232-1997, EN 12919-1999, and ISO 13137-2013, are revised. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

Novel Cell-Based Assays for Detecting Low Levels of Active Ricin Following Decontamination

DTIC Science & Technology

2011-12-01

fluorescent protein, are powerful tools, which have been used for detection assays for ricin protein ( DeWet , 1987). Zhao et al. (2005) have reported a...toxic Type 2 Ribosome-Inactivating Proteins. FEBS Lett. 2004, 563, pp 219–222. DeWet , J.R. et al. Firefly Luciferase Gene: Structure and

“Scanning mutagenesis” of the amino acid sequences flanking phosphorylation site 1 of the mitochondrial pyruvate dehydrogenase complex

USDA-ARS?s Scientific Manuscript database

The mitochondrial pyruvate dehydrogenase complex is regulated by reversible seryl-phosphorylation of the E1alpha subunit by a dedicated, intrinsic kinase. The phospho-complex is reactivated when dephosphorylated by an intrinsic PP2C-type protein phosphatase. Both the position of the phosphorylated...

Laser-induced fluorescence studies of premalignant and benign lesions in the female genital tract

NASA Astrophysics Data System (ADS)

af Klinteberg, Claes; Wang, Ingrid; Lindquist, Charlotta; Vaitkuviene, Aurelija; Svanberg, Katarina

1997-12-01

Laser-induced fluorescence (LIF) was studied in vivo from premalignant and benign lesions in the female genital tract, in particular the cervix. The aim of the study was to investigate the possibilities to differentiate cervical intraepithelial neoplasia (CIN) from normal tissue by means of two different fluorescence modalities. Most of the patients were given a low dose (5 mg/kg bw) of (delta) -amino levulinic acid (ALA). The ALA was orally administered 2 - 4 hours prior to the investigation. During this time, the ALA is transformed to the strongly fluorescent protoporphyrin IX (PpIX) via the haem cycle. Excitation light with a wavelength of 405 nm was used to excite the PpIX fluorescence. Excess amounts of PpIX were accumulated preferentially in diseased tissue. However, the variability in the PpIX accumulation from patient to patient was large. By using excitation light at 337 nm, the endogenous fluorophores are more efficiently excited. Therefore, this excitation modality was exploited for studying spectral characteristics of the autofluorescence in different tissue types. The spectra obtained were evaluated by forming fluorescence intensity ratios. The tissue types were grouped according to the histopathological examination. A correlation with the fluorescence ratios was performed. Some problems with the classification remain, mostly due to the difficulties in obtaining histopathologic evaluation of the biopsies at the exact location of the LIF measurements.

Core-shell AgSiO2-protoporphyrin IX nanoparticle: Effect of the Ag core on reactive oxygen species generation

NASA Astrophysics Data System (ADS)

Lismont, M.; Pá; ez-Martinez, C.; Dreesen, L.

2015-03-01

Photodynamic therapy (PDT) for cancer is based on the use of a light sensitive molecule to produce, under specific irradiation, toxic reactive oxygen species (ROS). A way to improve the therapy efficiency is to increase the amount of produced ROS near cancer cells. This aim can be achieved by using a metal enhanced process arising when an optically active molecule is located near a metallic nanoparticle (NP). Here, the coupling effect between silver (Ag) NPs and protoporphyrin IX (PpIX) molecules, a clinically approved photosensitizer, is studied compared first, to PpIX fluorescence yield and second, to ROS production efficiency. By applying a modified Stöber process, PpIX was encapsulated into a silica (SiO2) shell, surrounding a 60 nm sized Ag core. We showed that, compared to SiO2-PpIX NPs, Ag coated SiO2-PpIX NPs dramatically decreased PpIX fluorescence together with singlet oxygen production efficiency. However, after incubation time in the dark, the amount of superoxide anions generated by the Ag doped sample was higher than the control sample one.

A widespread family of serine/threonine protein phosphatases shares a common regulatory switch with proteasomal proteases

PubMed Central

Bradshaw, Niels; Levdikov, Vladimir M; Zimanyi, Christina M; Gaudet, Rachelle; Wilkinson, Anthony J; Losick, Richard

2017-01-01

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. DOI: http://dx.doi.org/10.7554/eLife.26111.001 PMID:28527238

Evidence for collective phenomena in pp collisions

NASA Astrophysics Data System (ADS)

Chen, Zhenyu; CMS Collaboration

2017-11-01

Measurements of two- and multi-particle angular correlations in pp collisions at √{ s} = 5, 7, and 13 TeV are presented. The data, corresponding to integrated luminosities of 1.0 pb-1 (5 TeV), 6.2 pb-1 (7 TeV), and 0.7 pb-1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of Ks0 and Λ / Λ ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), Ks0, and Λ / Λ ‾ at pT ≲ 2 GeV /c. The v2 signals are also extracted from four- and six-particle correlations for 13 TeV pp collisions, with comparable magnitude to those from two-particle correlations. These observations strongly support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.

Crystal structure of a protein phosphatase 2A heterotrimeric holoenzyme.

PubMed

Cho, Uhn Soo; Xu, Wenqing

2007-01-04

Protein phosphatase 2A (PP2A) is a principal Ser/Thr phosphatase, the deregulation of which is associated with multiple human cancers, Alzheimer's disease and increased susceptibility to pathogen infections. How PP2A is structurally organized and functionally regulated remains unclear. Here we report the crystal structure of an AB'C heterotrimeric PP2A holoenzyme. The structure reveals that the HEAT repeats of the scaffold A subunit form a horseshoe-shaped fold, holding the catalytic C and regulatory B' subunits together on the same side. The regulatory B' subunit forms pseudo-HEAT repeats and interacts with the C subunit near the active site, thereby defining substrate specificity. The methylated carboxy-terminal tail of the C subunit interacts with a highly negatively charged region at the interface between A and B' subunits, suggesting that the C-terminal carboxyl methylation of the C subunit promotes B' subunit recruitment by neutralizing charge repulsion. Together, our structural results establish a crucial foundation for understanding PP2A assembly, substrate recruitment and regulation.

[Contents of water-soluble vitamins in canned fish and seafood].

PubMed

Shmakova, S I; Shvidskaia, Z P; Dolbnina, L V

2000-01-01

Data of contents of vitamins (B1 and B2, C, PP) in production from gidrobionts is given. Is established, that the process of sterilization of canned food from gidrobionts in to container provides significant (almost twofold) decrease (reduction) of vitamins B1 [symbol: see text] B2, smaller losses of vitamin C (less than 30%) and proves to be true sufficient stability (almost on 85-90%) to action of high temperatures (120 degrees C) of vitamin PP. The canned food from sea gidrobionts represent the certain interest basically as a source of vitamin PP, and canned food "Herring smoked in oil"--vitamin B2. The canned food "Skobljanka from cucumber and fish" can be considered as a source of vitamins B2, C, PP.

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

Bahig, Houda; Simard, Dany; Létourneau, Laurent

Purpose: To determine the incidence of pseudoprogression (PP) after spine stereotactic body radiation therapy based on a detailed and quantitative assessment of magnetic resonance imaging (MRI) morphologic tumor alterations, and to identify predictive factors distinguishing PP from local recurrence (LR). Methods and Materials: A retrospective analysis of 35 patients with 49 spinal segments treated with spine stereotactic body radiation therapy, from 2009 to 2014, was conducted. The median number of follow-up MRI studies was 4 (range, 2-7). The gross tumor volumes (GTVs) within each of the 49 spinal segments were contoured on the pretreatment and each subsequent follow-up T1- andmore » T2-weighted MRI sagittal sequence. T2 signal intensity was reported as the mean intensity of voxels constituting each volume. LR was defined as persistent GTV enlargement on ≥2 serial MRI studies for ≥6 months or on pathologic confirmation. PP was defined as a GTV enlargement followed by stability or regression on subsequent imaging within 6 months. Kaplan-Meier analysis was used for estimation of actuarial local control, disease-free survival, and overall survival. Results: The median follow-up was 23 months (range, 1-39 months). PP was identified in 18% of treated segments (9 of 49) and LR in 29% (14 of 49). Earlier volume enlargement (5 months for PP vs 15 months for LR, P=.005), greater GTV to reference nonirradiated vertebral body T2 intensity ratio (+30% for PP vs −10% for LR, P=.005), and growth confined to 80% of the prescription isodose line (80% IDL) (8 of 9 PP cases vs 1 of 14 LR cases, P=.002) were associated with PP on univariate analysis. Multivariate analysis confirmed an earlier time to volume enlargement and growth within the 80% IDL as significant predictors of PP. LR involved the epidural space in all but 1 lesion, whereas PP was confined to the vertebral body in 7 of 9 cases. Conclusions: PP was observed in 18% of treated spinal segments. Tumor growth confined to the 80% IDL and earlier time to tumor enlargement were predictive for PP.« less

Phosphorylation of mammalian Sgo2 by Aurora B recruits PP2A and MCAK to centromeres

PubMed Central

Tanno, Yuji; Kitajima, Tomoya S.; Honda, Takashi; Ando, Yasuto; Ishiguro, Kei-ichiro; Watanabe, Yoshinori

2010-01-01

Shugoshin (Sgo) is a conserved centromeric protein. Mammalian Sgo1 collaborates with protein phosphatase 2A (PP2A) to protect mitotic cohesin from the prophase dissociation pathway. Although another shugoshin-like protein, Sgo2, is required for the centromeric protection of cohesion in germ cells, its precise molecular function remains largely elusive. We demonstrate that hSgo2 plays a dual role in chromosome congression and centromeric protection of cohesion in HeLa cells, while the latter function is exposed only in perturbed mitosis. These functions partly overlap with those of Aurora B, a kinase setting faithful chromosome segregation. Accordingly, we identified the phosphorylation of hSgo2 by Aurora B at the N-terminal coiled-coil region and the middle region, and showed that these phosphorylations separately promote binding of hSgo2 to PP2A and MCAK, factors required for centromeric protection and chromosome congression, respectively. Furthermore, these phosphorylations are essential for localizing PP2A and MCAK to centromeres. This mechanism seems applicable to germ cells as well. Thus, our study identifies Sgo2 as a hitherto unknown crucial cellular substrate of Aurora B in mammalian cells. PMID:20889715

Therapeutic benefits of a component of coffee in a rat model of Alzheimer's disease.

PubMed

Basurto-Islas, Gustavo; Blanchard, Julie; Tung, Yunn Chyn; Fernandez, Jose R; Voronkov, Michael; Stock, Maxwell; Zhang, Sherry; Stock, Jeffry B; Iqbal, Khalid

2014-12-01

A minor component of coffee unrelated to caffeine, eicosanoyl-5-hydroxytryptamide (EHT), provides protection in a rat model for Alzheimer's disease (AD). In this model, viral expression of the phosphoprotein phosphatase 2A (PP2A) endogenous inhibitor, the I2(PP2A), or SET protein in the brains of rats leads to several characteristic features of AD including cognitive impairment, tau hyperphosphorylation, and elevated levels of cytoplasmic amyloid-β protein. Dietary supplementation with EHT for 6-12 months resulted in substantial amelioration of all these defects. The beneficial effects of EHT could be associated with its ability to increase PP2A activity by inhibiting the demethylation of its catalytic subunit PP2Ac. These findings raise the possibility that EHT may make a substantial contribution to the apparent neuroprotective benefits associated with coffee consumption as evidenced by numerous epidemiologic studies indicating that coffee drinkers have substantially lowered risk of developing AD. Copyright © 2014 Elsevier Inc. All rights reserved.

Therapeutic benefits of a component of coffee in a rat model of Alzheimer disease1

PubMed Central

Basurto-Islas, Gustavo; Blanchard, Julie; Tung, Yunn Chyn; Fernandez, Jose R.; Voronkov, Michael; Stock, Maxwell; Zhang, Sherry; Stock, Jeffry B.; Iqbal, Khalid

2014-01-01

A minor component of coffee unrelated to caffeine, eicosanoyl-5-hydroxytryptamide (EHT) provides protection in a rat model for Alzheimer’s disease (AD). In this model, viral expression of the phosphoprotein phosphatase 2A (PP2A) endogenous inhibitor, the I2PP2A or SET protein in the brains of rats leads to several characteristic features of AD including cognitive impairment, tau hyperphosphorylation, and elevated levels of cytoplasmic β-amyloid protein. Dietary supplementation with EHT for 6–12 months resulted in substantial amelioration of all of these defects. The beneficial effects of EHT could be associated with its ability to increase PP2A activity by inhibiting the demethylation of its catalytic subunit PP2Ac. These findings raise the possibility that EHT may make a substantial contribution to the apparent neuroprotective benefits associated with coffee consumption as evidenced by numerous epidemiological studies indicating the coffee drinkers have substantially lowered risk of developing AD. PMID:25034344

Structure- and Modeling-based Identification of the Adenovirus E4orf4 Binding Site in the Protein Phosphatase 2A B55α Subunit*

PubMed Central

Horowitz, Ben; Sharf, Rakefet; Avital-Shacham, Meirav; Pechkovsky, Antonina; Kleinberger, Tamar

2013-01-01

The adenovirus E4orf4 protein regulates the progression of viral infection and when expressed outside the context of the virus it induces nonclassical, cancer cell-specific apoptosis. All E4orf4 functions known to date require an interaction between E4orf4 and protein phosphatase 2A (PP2A), which is mediated through PP2A regulatory B subunits. Specifically, an interaction with the B55α subunit is required for induction of cell death by E4orf4. To gain a better insight into the E4orf4-PP2A interaction, mapping of the E4orf4 interaction site in PP2A-B55α has been undertaken. To this end we used a combination of bioinformatics analyses of PP2A-B55α and of E4orf4, which led to the prediction of E4orf4 binding sites on the surface of PP2A-B55α. Mutation analysis, immunoprecipitation, and GST pulldown assays based on the theoretical predictions revealed that the E4orf4 binding site included the α1 and α2 helices described in the B55α structure and involved at least three residues located in these helices facing each other. Loss of E4orf4 binding was accompanied by reduced contribution of the B55α mutants to E4orf4-induced cell death. The identified E4orf4 binding domain lies above the previously described substrate binding site and does not overlap it, although its location could be consistent with direct or indirect effects on substrate binding. This work assigns for the first time a functional significance to the α1,α2 helices of B55α, and we suggest that the binding site defined by these helices could also contribute to interactions between PP2A and some of its cellular regulators. PMID:23530045

Differential Effects of Tautomycetin and Its Derivatives on Protein Phosphatase Inhibition, Immunosuppressive Function and Antitumor Activity

PubMed Central

Niu, Mingshan; Sun, Yan; Liu, Bo

2012-01-01

In the present work, we studied the structure-activity relationship (SAR) of tautomycetin (TMC) and its derivatives. Further, we demonstrated the correlation between the immunosuppressive fuction, anticancer activity and protein phosphatase type 1 (PP1) inhibition of TMC and its derivatives. We have prepared some TMC derivatives via combinatorial biosynthesis, isolation from fermentation broth or chemical degradation of TMC. We found that the immunosuppressive activity was correlated with anticancer activity for TMC and its analog compounds, indicating that TMC may home at the same targets for its immunosuppressive and anticancer activities. Interestingly, TMC-F1, TMC-D1 and TMC-D2 all retained significant, albeit reduced PP1 inhibitory activity compared to TMC. However, only TMC-D2 showed immunosuppressive and anticancer activities in studies carried out in cell lines. Moreover, TMC-Chain did not show any significant inhibitory activity towards PP1 but showed strong growth inhibitory effect. This observation implicates that the maleic anhydride moiety of TMC is critical for its phosphatase inhibitory activity whereas the C1-C18 moiety of TMC is essential for the inhibition of tumor cell proliferation. Furthermore, we measured in vivo phosphatase activities of PP1 in MCF-7 cell extracts treated with TMC and its related compounds, and the results indicate that the cytotoxicity of TMC doesn't correlate with its in vivo PP1 inhibition activity. Taken together, our study suggests that the immunosuppressive and anticancer activities of TMC are not due to the inhibition of PP1. Our results provide a novel insight for the elucidation of the underlying molecular mechanisms of TMC's important biological functions. PMID:22563261

Impacts of dietary calcium, phytate, and nonphytate phosphorus concentrations in the presence or absence of phytase on inositol hexakisphosphate (IP6) degradation in different segments of broilers digestive tract.

PubMed

Li, W; Angel, R; Kim, S-W; Brady, K; Yu, S; Plumstead, P W

2016-03-01

A total of 1,440 straight-run Heritage 56M × fast-feathering Cobb 500F broiler birds were fed from 11 to 13 d of age to determine the impacts of calcium (Ca), phytate phosphorus (PP), nonphytate P (NPP) and phytase concentrations on the myo-inositol hexakisphosphate (IP6) flow through the different parts of gastrointestinal tract (GIT). The experiment was a 2×2×2×3 randomized block design with 2 Ca (0.7 and 1.0%), 2 PP (0.23 and 0.34%), 2 nPP (0.28 and 0.45%) and 3 phytase (0-, 500-, and 1,000-phytase unit (FTU)/kg) concentrations. The experiment was replicated twice (block) with 3 replicates per treatment (TRT) of 10 birds per block. Concentration of IP6 in crop, proventriculus (PROV) plus (+) gizzard (GIZ) and distal ileum digesta as well as the ileal IP6 disappearance was determined at 13 d of age. In crop, higher IP6 concentration was seen with increased Ca (P < 0.05). Despite the interaction between PP and phytase, higher dietary PP led to greater IP6 concentration (P < 0.05). Similar main effects of PP and phytase were also seen in Prov+Giz and ileum (P < 0.05) without interactions. Interaction between Ca and nPP on IP6 concentration was seen in Prov+Giz (P < 0.05). Decreased ileal IP6 disappearance was found at higher Ca (62.3% at 0.7% Ca vs. 57.5% at 1.0% Ca; P < 0.05). In general, adding phytase improved IP6 degradation but the degree of impact was dependent on nPP and PP (P < 0.05). In conclusion, phytase inclusion significantly reduced IP6 concentration and IP6 disappearance in distal ileum regardless of GIT segments or diet composition, but impacts of dietary Ca, nPP, and PP differed depending on GIT segment examined. © The Author 2016. Published by Oxford University Press on behalf of Poultry Science Association.

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

Zissa, D.E.

The charged multiplicity cross sections of 50 GeV/c anti pp annihilation reactions are examined through the use of the corresponding anti pp - pp cross section differences. In addition, various four-constraint reactions such as the elastic reaction and the reaction anti pp ..-->.. anti pp ..pi../sup +/..pi../sup -/ are studied at the same incident anti p beam momentum. The source of the data is a film sample of 92,000 pictures of the 30-inch hydrogen bubble chamber exposed to an anti p enriched 50 GeV/c negative beam. There are 2.8 antiprotons per picture on the average. The proportional wire chambers allowmore » for precise measurement of beam and fast secondary charged particle trajectories. The average charged multiplicity of the difference distribution is larger than that of the anti pp sample as a whole. Although the anti pp - pp total cross section difference is approximately 12%, about 50% of the anti pp events with 14 charged particles appear in the difference. The difference distribution is in good agreement with a model by Eylon and Harari for anti pp annihilations. The model is based on simple counting rules for quark interaction diagrams. The form of the difference distribution has an energy dependence which may be interpreted as evidence for multiple cluster formation for anti pp annihilations above about 30 GeV. Alternatively, Koba-Nielsen-Olesen scaling describes the distribution over the entire range of existing data. Copius ..delta.. (1232) production and diffractive dissociation are exhibited in the reaction anti pp ..-->.. anti pp..pi../sup -/..pi../sup -/. The subchannel reaction anti pp ..-->.. anti ..delta../sup - -/..delta../sup - -/ is examined in terms of pion exchange. The cross sections for the reaction anti pp ..-->.. anti pp2..pi../sup -/2..pi../sup -/ is determined. No statistically significant amount of annihilation is found into two, four, and six charged pions without associated neutral particles.« less

Stimulation of the cardiac myocyte Na+-K+ pump due to reversal of its constitutive oxidative inhibition

PubMed Central

Chia, Karin K. M.; Liu, Chia-Chi; Hamilton, Elisha J.; Garcia, Alvaro; Fry, Natasha A.; Hannam, William; Figtree, Gemma A.

2015-01-01

Protein kinase C can activate NADPH oxidase and induce glutathionylation of the β1-Na+-K+ pump subunit, inhibiting activity of the catalytic α-subunit. To examine if signaling of nitric oxide-induced soluble guanylyl cyclase (sGC)/cGMP/protein kinase G can cause Na+-K+ pump stimulation by counteracting PKC/NADPH oxidase-dependent inhibition, cardiac myocytes were exposed to ANG II to activate NADPH oxidase and inhibit Na+-K+ pump current (Ip). Coexposure to 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole (YC-1) to stimulate sGC prevented the decrease of Ip. Prevention of the decrease was abolished by inhibition of protein phosphatases (PP) 2A but not by inhibition of PP1, and it was reproduced by an activator of PP2A. Consistent with a reciprocal relationship between β1-Na+-K+ pump subunit glutathionylation and pump activity, YC-1 decreased ANG II-induced β1-subunit glutathionylation. The decrease induced by YC-1 was abolished by a PP2A inhibitor. YC-1 decreased phosphorylation of the cytosolic p47phox NADPH oxidase subunit and its coimmunoprecipitation with the membranous p22phox subunit, and it decreased O2·−-sensitive dihydroethidium fluorescence of myocytes. Addition of recombinant PP2A to myocyte lysate decreased phosphorylation of p47phox indicating the subunit could be a substrate for PP2A. The effects of YC-1 to decrease coimmunoprecipitation of p22phox and p47phox NADPH oxidase subunits and decrease β1-Na+-K+ pump subunit glutathionylation were reproduced by activation of nitric oxide-dependent receptor signaling. We conclude that sGC activation in cardiac myocytes causes a PP2A-dependent decrease in NADPH oxidase activity and a decrease in β1 pump subunit glutathionylation. This could account for pump stimulation with neurohormonal oxidative stress expected in vivo. PMID:26084308

Enhancement of visible-light photoactivity by polypropylene coated plasmonic Au/TiO2 for dye degradation in water solution

NASA Astrophysics Data System (ADS)

D'Amato, C. A.; Giovannetti, R.; Zannotti, M.; Rommozzi, E.; Ferraro, S.; Seghetti, C.; Minicucci, M.; Gunnella, R.; Di Cicco, A.

2018-05-01

A new approach to obtain a heterogeneous photocatalytic material with gold nanoparticles and TiO2 semiconductor was performed exploiting the reducing ability of acetylacetone, a chemical present in the TiO2 paste formulation. Gold/TiO2 heterogeneous catalyst supported on polypropylene [PP@Au-TiO2]A was prepared; composition, structure and morphology of this new material were defined by using UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray diffraction (XRD), X-ray Fluorescence (XRF), Raman Spectroscopy, Photoluminescence and Diffuse Reflectance Spectroscopy. The new material was tested in the photocatalytic degradation of Alizarin Red S in water solution, as target pollutant, under visible light and correlated with structural and spectroscopic characterizations. [PP@Au-TiO2]A showed higher photocatalytic activity respect to pure [PP@TiO2]A with an improvement of photodegradation kinetic. The best performance was obtained using [PP@Au-TiO2]A sample with 0.006 wt.% of Au and the photocatalytic improvement was correlated with the band gap energy decrease of photocatalyst.

Crystallization efficiencies of inorganic polyphosphate oligomers reacted with magnesium and calcium cations using anion-exchange chromatography with particulate formation-laser scattering detector.

PubMed

Ando, Masaki; Imadzu, Sakiyo; Kitagawa, Shinya; Ohtani, Hajime

2010-08-06

A particulate formation-laser scattering detector (PFLSD) was developed and used for evaluating the crystallization efficiency of inorganic polyphosphates (PPs) that reacted with either magnesium or calcium cations. As the solutions for reactive crystallization, 0.5 M ammonium buffer (pH 9.6) containing either 0.15 M MgCl(2) or 0.15 M CaCl(2) (MAP: magnesium ammonium phosphate and HAP: hydroxyapatite solution) were used. In the case of mono- and diphosphate (P1 and P2), the significant dependences of the particulate formation efficiency on various types of both P1/P2 and MAP/HAP reaction solutions were observed with the direct sample injection mode. The PFLSD was hyphenated with the anion-exchange chromatography and the dependence of the particulate formation efficiency on the polymerization degree (n(p)) of PP oligomers, separated chromatographically, was evaluated sequentially. The significant suppression of the particulate formation for PP oligomers was clearly confirmed, i.e., the MAP and HAP reaction solutions did not produce the particulates of the PP oligomers having an n(p) value of more than 3 and 5, respectively. As the overall tendency, the particulate formation efficiency in the case of the HAP solution was superior to that in the case of the MAP solution. Copyright 2010 Elsevier B.V. All rights reserved.

Purification and molecular cloning of SH2- and SH3-containing inositol polyphosphate-5-phosphatase, which is involved in the signaling pathway of granulocyte-macrophage colony-stimulating factor, erythropoietin, and Bcr-Abl.

PubMed

Odai, H; Sasaki, K; Iwamatsu, A; Nakamoto, T; Ueno, H; Yamagata, T; Mitani, K; Yazaki, Y; Hirai, H

1997-04-15

Grb2/Ash and Shc are the adapter proteins that link tyrosine-kinase receptors to Ras and make tyrosine-kinase functionally associated with receptors and Ras in fibroblasts and hematopoietic cells. Grb2/Ash and Shc have the SH3, SH2, or phosphotyrosine binding domains. These domains bind to proteins containing proline-rich regions or tyrosine-phosphorylated proteins and contribute to the association of Grb2/Ash and Shc with other signaling molecules. However, there could remain unidentified signaling molecules that physically and functionally interact with these adapter proteins and have biologically important roles in the signaling pathways. By using the GST fusion protein including the full length of Grb2/Ash, we have found that c-Cbl and an unidentified 135-kD protein (pp135) are associated with Grb2/Ash. We have also found that they become tyrosine-phosphorylated by treatment of a human leukemia cell line, UT-7, with granulocyte-macrophage colony-stimulating factor (GM-CSF). We have purified the pp135 by using GST-Grb2/Ash affinity column and have isolated the full-length complementary DNA (cDNA) encoding the pp135 using a cDNA probe, which was obtained by the degenerate polymerase chain reaction based on a peptide sequence of the purified pp135. The cloned cDNA has 3,958 nucleotides that contain a single long open reading frame of 3,567 nucleotides, encoding a 1,189 amino acid protein with a predicted molecular weight of approximately 133 kD. The deduced amino acid sequence reveals that pp135 is a protein that has one SH2, one SH3, and one proline-rich domain. The pp135, which contains two motifs conserved among the inositol polyphosphate-5-phosphatase proteins, was shown to have the inositol polyphosphate-5-phosphatase activity. The pp135 was revealed to associate constitutively with Grb2/Ash and inducibly with Shc using UT-7 cells stimulated with GM-CSF. In the cell lines derived from human chronic myelogenous leukemia, pp135 was constitutively tyrosine-phosphorylated and associated with Shc and Bcr-Abl. These facts suggest that pp135 is a signaling molecule that has a unique enzymatic activity and should play an important role in the signaling pathway triggered by GM-CSF and in the transformation of hematopoietic cells caused by Bcr-Abl.

Receptor homodimerization plays a critical role in a novel dominant negative P2RY12 variant identified in a family with severe bleeding.

PubMed

Mundell, S J; Rabbolini, D; Gabrielli, S; Chen, Q; Aungraheeta, R; Hutchinson, J L; Kilo, T; Mackay, J; Ward, C M; Stevenson, W; Morel-Kopp, M-C

2018-01-01

Essentials Three dominant variants for the autosomal recessive bleeding disorder type-8 have been described. To date, there has been no phenotype/genotype correlation explaining their dominant transmission. Proline plays an important role in P2Y12R ligand binding and signaling defects. P2Y12R homodimer formation is critical for the receptor function and signaling. Background Although inherited platelet disorders are still underdiagnosed worldwide, advances in molecular techniques are improving disease diagnosis and patient management. Objective To identify and characterize the mechanism underlying the bleeding phenotype in a Caucasian family with an autosomal dominant P2RY12 variant. Methods Full blood counts, platelet aggregometry, flow cytometry and western blotting were performed before next-generation sequencing (NGS). Detailed molecular analysis of the identified variant of the P2Y12 receptor (P2Y12R) was subsequently performed in mammalian cells overexpressing receptor constructs. Results All three referred individuals had markedly impaired ADP-induced platelet aggregation with primary wave only, despite normal total and surface P2Y12R expression. By NGS, a single P2RY12:c.G794C substitution (p.R265P) was identified in all affected individuals, and this was confirmed by Sanger sequencing. Mammalian cell experiments with the R265P-P2Y12R variant showed normal receptor surface expression versus wild-type (WT) P2Y12R. Agonist-stimulated R265P-P2Y12R function (both signaling and surface receptor loss) was reduced versus WT P2Y12R. Critically, R265P-P2Y12R acted in a dominant negative manner, with agonist-stimulated WT P2Y12R activity being reduced by variant coexpression, suggesting dramatic loss of WT homodimers. Importantly, platelet P2RY12 cDNA cloning and sequencing in two affected individuals also revealed three-fold mutant mRNA overexpression, decreasing even further the likelihood of WT homodimer formation. R265 located within extracellular loop 3 (EL3) is one of four residues that are important for receptor functional integrity, maintaining the binding pocket conformation and allowing rotation following ligand binding. Conclusion This novel dominant negative variant confirms the important role of R265 in EL3 in the functional integrity of P2Y12R, and suggests that pathologic heterodimer formation may underlie this family bleeding phenotype. © 2017 International Society on Thrombosis and Haemostasis.

Can poly-parameter linear-free energy relationships (pp-LFERs) improve modelling bioaccumulation in fish?

PubMed

Zhao, Shizhen; Jones, Kevin C; Sweetman, Andrew J

2018-01-01

A wide range of studies have characterized different types of biosorbent, with regard to their interactions with chemicals. This has resulted in the development of poly-parameter linear free energy relationships (pp-LFERs) for the estimation of partitioning of neutral organic compounds to biological phases (e.g., storage lipids, phospholipids and serum albumins). The aims of this study were to explore and evaluate the influence of implementing pp-LFERs both into a one-compartment fish model and a multi-compartment physiologically based toxicokinetic (PBTK) fish model and the associated implications for chemical risk assessment. For this purpose, fish was used as reference biota, due to their important role in aquatic food chains and dietary exposure to humans. The bioconcentration factor (BCF) was utilized as the evaluation metric. Overall, our results indicated that models incorporating pp-LFERs (R 2  = 0.75) slightly outperformed the single parameter (sp) LFERs approach in the one-compartmental fish model (R 2  = 0.72). A pronounced enhancement was achieved for compounds with log K OW between 4 and 5 with increased R 2 from 0.52 to 0.71. The minimal improvement was caused by the overestimation of lipid contribution and underestimation of protein contribution by the sp-approach, which cancelled each other out. Meanwhile, a greater improvement was observed for multi-compartmental PBTK models with consideration of metabolism, making all predictions fall within a factor of 10 compared with measured data. For screening purposes, the K OW -based (sp-LFERs) approach should be sufficient to quantify the main partitioning characteristics. Further developments are required for the consideration of ionization and more accurate quantification of biotransformation in biota. Copyright © 2017 Elsevier Ltd. All rights reserved.

Relative abundances of chondrule primary textural types in ordinary chondrites and their bearing on conditions of chondrule formation

NASA Astrophysics Data System (ADS)

Gooding, J. L.; Keil, K.

1981-03-01

A petrographic survey of > 1600 chondrules in thin-sections of 12 different mildly to highly unequilibrated H-, L-, and Li-chondrites, as well as morphological and textural study of 141 whole chondrules separated from 11 of the same chondrites, was used to determine the relative abundances of definable chondrule primary textural types. Percentage abundances of various chondrule types are remarkably similar in all chondrites studied and are ˜47-52 porphyritic olivine-pyroxene (POP), 15-27 porphyritic olivine (P 0), 9-11 porphyritic pyroxene (PP), 34 barred olivine (BO), 7-9 radial pyroxene (RP), 2-5 granular olivine-pyroxene (GOP), 3-5 cryptocrystalline (C), and ≥ 1 metallic (M). Neither chondrule size nor shape is strongly correlated with textural type. Compound and cratered chondrules, which are interpreted as products of collisions between plastic chondrules, comprise ˜2-28% of non-porphyritic (RP, GOP, C) but only ˜2-9% of porphyritic (POP, PO, PP, BO) chondrules, leading to a model-dependent implication that non-porphyritic chondrules evolved at number densities (chondrules per unit volume of space) which were 102 to 104 times greater than those which prevailed during porphyritic chondrule formation (total range of ˜1 to ˜106 m-3. Distinctive "rims" of fine-grained sulfides and/or silicates occur on both porphyritic and non-porphyritic types and appear to post-date chondrule formation. Apparently, either the same process(es) contributed chondrules to all unequilibrated ordinary chondrites or, if genetically different, the various chondrule types were well mixed before incorporation into chondrites. Melting of pre-existing materials is the mechanism favored for chondrule formation.

Invasive placenta previa: Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta.

PubMed

Chen, Xin; Shan, Ruiqin; Zhao, Lianxin; Song, Qingxu; Zuo, Changting; Zhang, Xinjuan; Wang, Shanshan; Shi, Honglu; Gao, Fei; Qian, Tianyi; Wang, Guangbin; Limperopoulos, Catherine

2018-02-01

To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. Significant differences were found in nine MRI features between women with PP and those with PA (P <0.05). Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P < 0.001; odds ratio = 4.165, P = 0.018 respectively), and the combination of the two MRI features to distinguish PP from PA yielded an AUC of 0.92 for its predictive performance. Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. • Placental bulge type-II demonstrated the strongest independent association with PP. • Uterine serosal hypervascularity is a useful feature for differentiating PP from PA. • MRI features associated with abnormal vessels increase the risk of massive haemorrhage.

Effects of low-level SO/sub 2/ on Usnes hirta and Parmelia chlorachroa

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

Eversman, S.

1978-01-01

Respiration rates of Usnea hirta (l.) wigg, and Parmelia chlorochroa tuck exposed in the field to SO/sub 2/ fumigation decreased significantly, compared to control rates, within 30 days at 94 ppB SO/sub 2/ and within 60 days at 33 ppB. Nearly 100% of the algal cells were plasmolyzed within 60 days. The respiration rates of P. chlorochora samples were not significantly different from those of conrol samples after 60 days of exposure to 18 ppB SO/sub 2/. The respiration rates of U. hirta samples were significantly less than those of control samples after 96 days of exposure to 18 ppBmore » SO/sub 2/. A significantly greater percentage of the algal cells were plasmolyzed in U. hirta and P. chlorochroa, compared to control samples, after 31 days of exposure to 18 ppB. Damage to the lichens was more obvious and occurred faster than damage to adjacent vascular vegetation.« less

Analyses of expression and localization of two mammalian-type transglutaminases in Physarum polycephalum, an acellular slime mold.

PubMed

Wada, Fumitaka; Ogawa, Atsuko; Hanai, Yuko; Nakamura, Akio; Maki, Masatoshi; Hitomi, Kiyotaka

2004-11-01

Transglutaminase (TGase) is an enzyme that modifies proteins by crosslinking or polyamination. Physarum polycephalum, an acellular slime mold, is the evolutionally lowest organism that has a mammalian-type transglutaminase. We have cloned a cDNA for Physarum polycephalum TGase (PpTGB), homologous to a previously identified TGase (PpTGA), whose sequence is similar to that of mammalian TGases. PpTGB encodes a primary sequence identical to that of PpTGA except for 11 amino acid residues at the N-terminus. Reverse transcription-PCR and Western blotting analyses showed that both PpTGA and PpTGB are expressed in microplasmodia and macroplasmodia during their life cycle, except for in sporangia. For biochemical characterization, we carried out the ectopical expressions of PpTGA and PpTGB in Dictyostelium discoideum. Subcellular fractionation of these Dictyostelium cells showed that the expressed PpTGA, but not PpTGB, localizes to the membrane fraction. Furthermore, in Physarum, subcellular fractionation and immunostaining indicated specific localization at the plasma membrane in macroplasmodia, while the localization was entirely cytoplasmic in microplasmodia.

Elevated Markers of Vascular Remodeling and Arterial Stiffness Are Associated with Neurocognitive Function in Older HIV+ Adults on Suppressive Antiretroviral Therapy

PubMed Central

Montoya, Jessica L.; Iudicello, Jennifer; Fazeli, Pariya L.; Hong, Suzi; Potter, Michael; Ellis, Ronald J.; Grant, Igor; Letendre, Scott L.; Moore, David J.

2016-01-01

Background HIV is associated with elevated markers of vascular remodeling that may contribute to arterial fibrosis and stiffening, and changes in pulse pressure (PP). These changes may, in turn, deleteriously affect autoregulation of cerebral blood flow and neurocognitive function. Methods To evaluate these mechanisms, we studied markers of vascular remodeling, PP, and neurocognitive function among older (≥50 years of age) HIV-infected (HIV+; n = 72) and HIV-seronegative (HIV-; n = 36) adults. Participants completed standardized neurobehavioral and neuromedical assessments. Neurocognitive functioning was evaluated using a well-validated comprehensive battery. Three plasma biomarkers of vascular remodeling (i.e., angiopoietin 2, Tie-2, and vascular endothelial growth factor; VEGF) were collected. Results HIV+ and HIV- participants had similar levels of plasma Ang-2 (p = .48), Tie-2 (p = .27), VEGF (p = .18), and PP (p = .98). In a multivariable regression model, HIV interacted with Tie-2 (β = .41, p < .01) and VEGF (β = −.43, p = .01) on neurocognitive function, such that lower Tie-2 and higher VEGF values were associated with worse neurocognitive function for HIV+ participants. Greater Tie-2 values were associated with increased PP (r = .31, p < .01). In turn, PP demonstrated a quadratic association with neurocognitive function (β = −.33, p = .01), such that lower and higher, relative to mean sample, PP values were associated with worse neurocognitive function. Conclusions These findings indicate that vascular remodeling and altered cerebral blood flow autoregulation contribute to neurocognitive function. Furthermore, HIV moderates the association between vascular remodeling and neurocognitive function but not the association between PP and neurocognitive function. PMID:27828873

Analysis of the apiclutural industry in relation to geothermal development and agriculture in the Imperial Valley, Imperial County, California

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

Atkins, E.L.

PART I: Continuous exposure to 30 ppB H/sub 2/S increased lifespan of caged worker honey bees, Apis mellifera L., 33%; whereas, bees exposed > 13 days to 100 ppB and 300 ppB H/sub 2/S the lifespan was shortened 32% and 51%, respectively, over unexposed bees; bees exposed > 15 days to a combination of 300 ppB H/sub 2/S + 50 ppM CO/sub 2/ the lifespan was shortened 4.4% more that 300 ppB H/sub 2/S alone. The mean temperature and/or relative humidity did not exert a direct effect on the hazard to bees. A continuous exposure to 300 ppB SO/sub 2/more » was detrimental to caged worker honey bees; and, a mean temperature of 27.2/sup 0/C was 75.7% more toxic than the same dosage at 16.7/sup 0/C. Worker bee lifespans exposed to 300 ppB SO/sub 2/ at 16.7/sup 0/C were shortened 13.5% and 79%, respectively, compared to unexposed bees. Therefore, both dosage and temperature exert direct effects on the hazards to bees. PART II: The status of the apicultural industry in Imperial County, California, was outlined giving a short characterization of the area in relation to the apicultural industry. Agriculture utilizes 500,000 intensely farmed acres which generated a 11-year average income of $370 million. Over 40 agricultural commodities are produced. The apicultural industry is intimately involved in 25% of the total gross agricultural income. In addition, most of the flora growing in the desert community which comprises the remainder of the county are very important to honey bees by providing sustaining nectar and/or pollen for brood rearing. The bee foraged flora provides substantial bee forage when colonies are located outside of the agriculutral area. It is concluded that geothermal resource development in the Imperial Valley is contemplated to have minimal effects on the apicultural industry.« less

The NAC transcription factor family in maritime pine (Pinus Pinaster): molecular regulation of two genes involved in stress responses.

PubMed

Pascual, Ma Belén; Cánovas, Francisco M; Ávila, Concepción

2015-10-24

NAC transcription factors comprise a large plant-specific gene family involved in the regulation of diverse biological processes. Despite the growing number of studies on NAC transcription factors in various species, little information is available about this family in conifers. The goal of this study was to identify the NAC transcription family in maritime pine (Pinus pinaster), to characterize ATAF-like genes in response to various stresses and to study their molecular regulation. We have isolated two maritime pine NAC genes and using a transient expression assay in N. benthamiana leaves estudied the promoter jasmonate response. In this study, we identified 37 NAC genes from maritime pine and classified them into six main subfamilies. The largest group includes 12 sequences corresponding to stress-related genes. Two of these NAC genes, PpNAC2 and PpNAC3, were isolated and their expression profiles were examined at various developmental stages and in response to various types of stress. The expression of both genes was strongly induced by methyl jasmonate (MeJA), mechanical wounding, and high salinity. The promoter regions of these genes were shown to contain cis-elements involved in the stress response and plant hormonal regulation, including E-boxes, which are commonly found in the promoters of genes that respond to jasmonate, and binding sites for bHLH proteins. Using a transient expression assay in N. benthamiana leaves, we found that the promoter of PpNAC3 was rapidly induced upon MeJA treatment, while this response disappeared in plants in which the transcription factor NbbHLH2 was silenced. Our results suggest that PpNAC2 and PpNAC3 encode stress-responsive NAC transcription factors involved in the jasmonate response in pine. Furthermore, these data also suggest that the jasmonate signaling pathway is conserved between angiosperms and gymnosperms. These findings may be useful for engineering stress tolerance in pine via biotechnological approaches.

Association of PAEs with Precocious Puberty in Children: A Systematic Review and Meta-Analysis.

PubMed

Wen, Yi; Liu, Shu-Dan; Lei, Xun; Ling, Yu-Shuang; Luo, Yan; Liu, Qin

2015-12-01

Precocious puberty (PP) currently affects 1 in 5000 children and is 10 times more common in girls. Existing studies have tried to detect an association between phathalic acid esters (PAEs) and PP, but the results did not reach a consensus. To estimate the association between PAEs and children with PP based on current evidence. Databases including PubMed (1978 to March 2015), OVID (1946 to March 2015), Web of Science (1970 to March 2015), EBSCO (1976 to March 2015), CNKI (1979 to March 2015), WANFANG DATA (1987 to March 2015), CBM (1978 to March 2015) and CQVIP (1989 to March 2015) were searched to identify all case-control studies that determined the exposure and concentration of PAEs and their metabolites in children with PP. Meta-analysis of the pooled standard mean difference (SMD) and odds ratio (OR) with 95% confidence intervals (CI) were calculated. A total of 14 studies involving 2223 subjects were finally included. The pooled estimates showed that PP was associated with di-(2-ethylhexyl)-phthalate (DEHP) exposure (OR: 3.90, 95% CI: 2.77 to 5.49). Besides, the concentration of DEHP (SMD: 1.73, 95% CI: 0.54 to 2.91) and di-n-butyl phthalate (DBP) (SMD: 4.31, 95% CI: 2.67 to 5.95) in the PP group were significantly higher than those in the control group, respectively, while no difference was detected between case and control groups in either serum or urinary concentration of mono-(2-ethylhexyl)-phthalate (MEHP), monobutyl phthalate (MBP), mono(2-ethyl-5-oxohexyl) phthalate(MEOHP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), monomethyl phthalate (MMP), monobenzyl phthalate (MBzP) or monoethyl phthalate (MEP). Exposure of DEHP and DBP might be associated with PP risk for girls, however, there is no evidence to show an association between the exposure to most PAE metabolites and PP. Given the moderate strength of the results, well-designed cohort studies with large sample size should be performed in future.

Suggested Involvement of PP1/PP2A Activity and De Novo Gene Expression in Anhydrobiotic Survival in a Tardigrade, Hypsibius dujardini, by Chemical Genetic Approach.

PubMed

Kondo, Koyuki; Kubo, Takeo; Kunieda, Takekazu

2015-01-01

Upon desiccation, some tardigrades enter an ametabolic dehydrated state called anhydrobiosis and can survive a desiccated environment in this state. For successful transition to anhydrobiosis, some anhydrobiotic tardigrades require pre-incubation under high humidity conditions, a process called preconditioning, prior to exposure to severe desiccation. Although tardigrades are thought to prepare for transition to anhydrobiosis during preconditioning, the molecular mechanisms governing such processes remain unknown. In this study, we used chemical genetic approaches to elucidate the regulatory mechanisms of anhydrobiosis in the anhydrobiotic tardigrade, Hypsibius dujardini. We first demonstrated that inhibition of transcription or translation drastically impaired anhydrobiotic survival, suggesting that de novo gene expression is required for successful transition to anhydrobiosis in this tardigrade. We then screened 81 chemicals and identified 5 chemicals that significantly impaired anhydrobiotic survival after severe desiccation, in contrast to little or no effect on survival after high humidity exposure only. In particular, cantharidic acid, a selective inhibitor of protein phosphatase (PP) 1 and PP2A, exhibited the most profound inhibitory effects. Another PP1/PP2A inhibitor, okadaic acid, also significantly and specifically impaired anhydrobiotic survival, suggesting that PP1/PP2A activity plays an important role for anhydrobiosis in this species. This is, to our knowledge, the first report of the required activities of signaling molecules for desiccation tolerance in tardigrades. The identified inhibitory chemicals could provide novel clues to elucidate the regulatory mechanisms underlying anhydrobiosis in tardigrades.

Suggested Involvement of PP1/PP2A Activity and De Novo Gene Expression in Anhydrobiotic Survival in a Tardigrade, Hypsibius dujardini, by Chemical Genetic Approach

PubMed Central

Kondo, Koyuki; Kubo, Takeo; Kunieda, Takekazu

2015-01-01

Upon desiccation, some tardigrades enter an ametabolic dehydrated state called anhydrobiosis and can survive a desiccated environment in this state. For successful transition to anhydrobiosis, some anhydrobiotic tardigrades require pre-incubation under high humidity conditions, a process called preconditioning, prior to exposure to severe desiccation. Although tardigrades are thought to prepare for transition to anhydrobiosis during preconditioning, the molecular mechanisms governing such processes remain unknown. In this study, we used chemical genetic approaches to elucidate the regulatory mechanisms of anhydrobiosis in the anhydrobiotic tardigrade, Hypsibius dujardini. We first demonstrated that inhibition of transcription or translation drastically impaired anhydrobiotic survival, suggesting that de novo gene expression is required for successful transition to anhydrobiosis in this tardigrade. We then screened 81 chemicals and identified 5 chemicals that significantly impaired anhydrobiotic survival after severe desiccation, in contrast to little or no effect on survival after high humidity exposure only. In particular, cantharidic acid, a selective inhibitor of protein phosphatase (PP) 1 and PP2A, exhibited the most profound inhibitory effects. Another PP1/PP2A inhibitor, okadaic acid, also significantly and specifically impaired anhydrobiotic survival, suggesting that PP1/PP2A activity plays an important role for anhydrobiosis in this species. This is, to our knowledge, the first report of the required activities of signaling molecules for desiccation tolerance in tardigrades. The identified inhibitory chemicals could provide novel clues to elucidate the regulatory mechanisms underlying anhydrobiosis in tardigrades. PMID:26690982

Mechanical loading stimulates chondrogenesis via the PKA/CREB-Sox9 and PP2A pathways in chicken micromass cultures.

PubMed

Juhász, Tamás; Matta, Csaba; Somogyi, Csilla; Katona, Éva; Takács, Roland; Soha, Rudolf Ferenc; Szabó, István A; Cserháti, Csaba; Sződy, Róbert; Karácsonyi, Zoltán; Bakó, Eva; Gergely, Pál; Zákány, Róza

2014-03-01

Biomechanical stimuli play important roles in the formation of articular cartilage during early foetal life, and optimal mechanical load is a crucial regulatory factor of adult chondrocyte metabolism and function. In this study, we undertook to analyse mechanotransduction pathways during in vitro chondrogenesis. Chondroprogenitor cells isolated from limb buds of 4-day-old chicken embryos were cultivated as high density cell cultures for 6 days. Mechanical stimulation was carried out by a self-designed bioreactor that exerted uniaxial intermittent cyclic load transmitted by the culture medium as hydrostatic pressure and fluid shear to differentiating cells. The loading scheme (0.05 Hz, 600 Pa; for 30 min) was applied on culturing days 2 and 3, when final commitment and differentiation of chondroprogenitor cells occurred in this model. The applied mechanical load significantly augmented cartilage matrix production and elevated mRNA expression of several cartilage matrix constituents, including collagen type II and aggrecan core protein, as well as matrix-producing hyaluronan synthases through enhanced expression, phosphorylation and nuclear signals of the main chondrogenic transcription factor Sox9. Along with increased cAMP levels, a significantly enhanced protein kinase A (PKA) activity was also detected and CREB, the archetypal downstream transcription factor of PKA signalling, exhibited elevated phosphorylation levels and stronger nuclear signals in response to mechanical stimuli. All the above effects were diminished by the PKA-inhibitor H89. Inhibition of the PKA-independent cAMP-mediators Epac1 and Epac2 with HJC0197 resulted in enhanced cartilage formation, which was additive to that of the mechanical stimulation, implying that the chondrogenesis-promoting effect of mechanical load was independent of Epac. At the same time, PP2A activity was reduced following mechanical load and treatments with the PP2A-inhibitor okadaic acid were able to mimic the effects of the intervention. Our results indicate that proper mechanical stimuli augment in vitro cartilage formation via promoting both differentiation and matrix production of chondrogenic cells, and the opposing regulation of the PKA/CREB-Sox9 and the PP2A signalling pathways is crucial in this phenomenon. Copyright © 2014 Elsevier Inc. All rights reserved.

Induction of parturition with prostaglandin f2 alpha as a possible model to study impaired reproductive performance in the dairy cow.

PubMed

Kask, K; Gustafsson, H; Gunnarsson, A; Kindahl, H

2000-05-31

Parturitions were induced in five cows, 2 weeks before term using prostaglandin (PG) F(2alpha). Two i.m. injections were performed with an interval of 24 h. All cows calved within 5 days (average 2.7 days) after the first injection of PGF(2alpha). Out of five cows, four had retained fetal membranes (RFM). Each animal was sampled for bacteriological examination using uterine biopsies twice a week during 42 days postpartum (PP). Jugular vein blood samples were withdrawn for PGF(2alpha)-metabolite and progesterone analyses five times per day during the first week PP and eight times per 24 h during the 2nd and 3rd weeks PP. From the 4th week, the sampling interval was reduced back to five times per day. From the 5th week PP, the sampling was reduced to two times per day and sampling was terminated after day 46 PP. Only morning samples were used for progesterone analyses. From day 10 PP, ultrasonography (US) was performed every 3rd day until day 39 PP for detection of ovarian activity and follicular dynamics. The highest incidence of bacteriological species was found during the first 3 weeks PP. After the 5th week of collection, all animals were free from bacteria. The species of bacteria found were Arcanobacterium (Actinomyces) pyogenes, Escherichia coli, alpha-hemolytic streptococcae and Pasteurella multocida. Immediately after parturition, very high levels of the PG-metabolite were seen in all animals, with a sharp decrease to line of significance around days 9-12 PP. Small increases above the line of significance were detected up to day 27 PP in cows with RFM, and after that time the levels were considered to be at baseline. Low levels of progesterone were seen in four animals during the whole experimental time. In one animal, an increase was seen on day 43 PP, which was maintained until the end of the experimental period on day 46 PP. Based on US, follicular waves were detected in all animals during the experimental period. In three animals, three non-ovulatory follicular waves were detected and in two animals, four non-ovulatory follicular waves were detected during 39 days of ultrasound sessions. Based on progesterone levels, only one animal was considered to have ovulated around day 40 PP. Results from the present study indicate that reproductive performance of cows after PG-induced parturitions differs from those of spontaneous cases of RFM. Differences regarding the resumption of ovarian activity were also observed between previous studies of dexamethasone-induced parturitions and the present study.

Characterising primary productivity measurements across a dynamic western boundary current region

NASA Astrophysics Data System (ADS)

Everett, Jason D.; Doblin, Martina A.

2015-06-01

Determining the magnitude of primary production (PP) in a changing ocean is a major research challenge. Thousands of estimates of marine PP exist globally, but there remain significant gaps in data availability, particularly in the Southern Hemisphere. In situ PP estimates are generally single-point measurements and therefore we rely on satellite models of PP in order to scale up over time and space. To reduce the uncertainty around the model output, these models need to be assessed against in situ measurements before use. This study examined the vertically-integrated productivity in four water-masses associated with the East Australian Current (EAC), the major western boundary current (WBC) of the South Pacific. We calculated vertically integrated PP from shipboard 14C PP estimates and then compared them to estimates from four commonly used satellite models (ESQRT, VGPM, VGPM-Eppley, VGPM-Kameda) to assess their utility for this region. Vertical profiles of the water-column show each water-mass had distinct temperature-salinity signatures. The depth of the fluorescence-maximum (fmax) increased from onshore (river plume) to offshore (EAC) as light penetration increased. Depth integrated PP was highest in river plumes (792±181 mg C m-2 d-1) followed by the EAC (534±116 mg C m-2 d-1), continental shelf (140±47 mg C m-2 d-1) and cyclonic eddy waters (121±4 mg C m-2 d-1). Surface carbon assimilation efficiency was greatest in the EAC (301±145 mg C (mg Chl-a)-1 d-1) compared to other water masses. All satellite primary production models tested underestimated EAC PP and overestimated continental shelf PP. The ESQRT model had the highest skill and lowest bias of the tested models, providing the best first-order estimates of PP on the continental shelf, including at a coastal time-series station, Port Hacking, which showed considerable inter-annual variability (155-2957 mg C m-2 d-1). This work provides the first estimates of depth integrated PP associated with the East Australian Current in temperate Australia. The ongoing intensification of all WBCs makes it critical to understand the variability in PP at the regional scale. More accurate predictions in the EAC region will require vertically-resolved in situ productivity and bio-optical measurements across multiple time scales to allow development of other models which simulate dynamic ocean conditions.

Experimental investigation on flexure and impact properties of injection molded polypropylene-nylon 6-glass fiber polymer composites

NASA Astrophysics Data System (ADS)

Nuruzzaman, D. M.; Kusaseh, N. M.; Chowdhury, M. A.; Rahman, N. A. N. A.; Oumer, A. N.; Fatchurrohman, N.; Iqbal, A. K. M. A.; Ismail, N. M.

2018-04-01

In this research study, glass fiber (GF) reinforced polypropylene (PP)-nylon 6 (PA6) polymer blend composites were prepared using injection molding process. Specimens of four different compositions such as 80%PP+20%PA6, 80%PP+18%PA6+2%GF, 80%PP+16%PA6+4%GF and 80%PP+14%PA6+6%GF were prepared. In the injection molding process, suitable process parameters were selected depending on the type of composite specimen in producing defects free dog bone shaped specimens. Flexure and impact tests were carried out according to ASTM standard. The important flexure properties such as flexural modulus, flexural yield strength, flexural strength and flexural strain were investigated. The obtained results revealed that flexural modulus of 80%PP+20%PA6 polymer blend is the lowest and the polymer blend composite shows steadily improved modulus as the glass fiber content is increased. Results also showed that flexural strength of pure polymer blend is the lowest but it improves gradually when the glass fiber content is increased. Impact test results revealed that impact strength of 80%PP+20%PA6 polymer blend is the highest whereas all the composites show reduced impact strength or toughness. It is noticed that 80%PP+14%PA6+6%GF composite exhibits the lowest impact strength.

Peach MYB7 activates transcription of the proanthocyanidin pathway gene encoding leucoanthocyanidin reductase, but not anthocyanidin reductase

PubMed Central

Zhou, Hui; Lin-Wang, Kui; Liao, Liao; Gu, Chao; Lu, Ziqi; Allan, Andrew C.; Han, Yuepeng

2015-01-01

Proanthocyanidins (PAs) are a group of natural phenolic compounds that have a great effect on both flavor and nutritious value of fruit. It has been shown that PA synthesis is regulated by R2R3-MYB transcription factors (TFs) via activation of PA-specific pathway genes encoding leucoanthocyanidin reductase and anthocyanidin reductase. Here, we report the isolation and characterization of a MYB gene designated PpMYB7 in peach. The peach PpMYB7 represents a new group of R2R3-MYB genes regulating PA synthesis in plants. It is able to activate transcription of PpLAR1 but not PpANR, and has a broader selection of potential bHLH partners compared with PpMYBPA1. Transcription of PpMYB7 can be activated by the peach basic leucine-zipper 5 TF (PpbZIP5) via response to ABA. Our study suggests a transcriptional network regulating PA synthesis in peach, with the results aiding the understanding of the functional divergence between R2R3-MYB TFs in plants. PMID:26579158

Nutritional geometry of calcium and phosphorus nutrition in broiler chicks. The effect of different dietary calcium and phosphorus concentrations and ratios on nutrient digestibility.

PubMed

Wilkinson, S J; Bradbury, E J; Thomson, P C; Bedford, M R; Cowieson, A J

2014-07-01

A total of 600 Ross 308-day-old male broiler chicks were used in a 28 day digestibility study to investigate the interaction between dietary calcium (Ca) and non-phytate phosphorus (nPP) on the digestibility of minerals and amino acids. Diets were formulated to be nutritionally adequate except for Ca and nPP. Fifteen mash diets based on corn and soya bean meal with varying concentrations of Ca (6.4 to 12.0 g/kg) and nPP (2.4 to 7.0 g/kg) were used. Diets were clustered around total densities of Ca and nPP of 12, 13.5 or 15.0 (g/kg) and within each density, a range of five Ca : nPP ratios (1.14 : 1, 1.5 : 1, 2.0 : 1, 2.75 : 1 and 4.0 : 1) were fed. Birds had free access to feed and water throughout the study. At day 28, birds were euthanised for the determination of apparent ileal mineral and amino acid digestibility. Data were modelled in R version 2.15 using a linear mixed-effects model and interrogation of the data was performed by fitting a low order polynomial function. At high Ca concentrations, increasing nPP led to an increase in the apparent digestibility of minerals. Apparent ileal digestibility of phosphorus (P) was enhanced with increasing dietary nPP up to 5.5 g/kg beyond which no improvements were found. Maximal Ca digestibility was found in diets with >8.0 g/kg Ca with concomitant low concentrations of nPP. Diets with a broader Ca : nPP ratio improved the digestibility of Ca but were deleterious to the digestibility of P. In this study, apparent digestibility of amino acids was broadly unaffected by dietary Ca and nPP concentrations. However, interactions between Ca and nPP were observed for the digestibility of glutamine, tyrosine and methionine (all P<0.001). Nitrogen digestibility showed discrete optima around 10.0 and 5.0 g/kg nPP and Na digestibility was maximised around 8 to 9.0 g/kg Ca and 4.5 to 5.4 g/kg nPP. These data show that the ratio of Ca : nPP is more influential to mineral digestibility than the absolute dietary concentration of each macro mineral.

Direct laser writing of synthetic poly(amino acid) hydrogels and poly(ethylene glycol) diacrylates by two-photon polymerization.

PubMed

Käpylä, Elli; Sedlačík, Tomáš; Aydogan, Dogu Baran; Viitanen, Jouko; Rypáček, František; Kellomäki, Minna

2014-10-01

The additive manufacturing technique of direct laser writing by two-photon polymerization (2PP-DLW) enables the fabrication of three-dimensional microstructures with superior accuracy and flexibility. When combined with biomimetic hydrogel materials, 2PP-DLW can be used to recreate the microarchitectures of the extracellular matrix. However, there are currently only a limited number of hydrogels applicable for 2PP-DLW. In order to widen the selection of synthetic biodegradable hydrogels, in this work we studied the 2PP-DLW of methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s). The performance of these materials was compared to widely used poly(ethylene glycol) diacrylates (PEGdas) in terms of polymerization and damage thresholds, voxel size, line width, post-polymerization swelling and deformation. We found that both methacryloylated and acryloylated poly(AA) hydrogels are suitable to 2PP-DLW with a wider processing window than PEGdas. The poly(AA) with the highest degree of acryloylation showed the greatest potential for 3D microfabrication. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel polypropylene/inorganic fullerene-like WS2 nanocomposites containing a β-nucleating agent: isothermal crystallization and melting behavior.

PubMed

Naffakh, Mohammed; Marco, Carlos; Ellis, Gary

2012-02-16

The isothermal crystallization and subsequent melting behavior of isotactic polypropylene (iPP) nucleated with different nucleating agents (NAs) are investigated. Tungsten disulfide (IF-WS(2)) and N,N'-dicyclohexyl-2,6-naphthalene (NJ) and dual-additive mixtures are introduced into an iPP matrix to generate new materials that exhibit variable α- and β-polymorphism. As shown in previous work, small amounts of IF-WS(2) or NJ have a nucleating effect during the crystallization of iPP. However, the isothermal crystallization and melting behavior of iPP nucleated by dual α(IF-WS(2))/β(NJ) additive systems are dependent on both the NA composition balance and the crystallization temperature. In particular, our results demonstrate that it is possible to obtain any α-phase to β-phase content ratio by controlling the composition of NAs under appropriate isothermal crystallization conditions. The nucleating behavior of the additives can be illustrated by competitive nucleation, and the correlation between crystallization and melting temperatures and relative α- and β-crystals content in iPP in the nanocomposites is discussed.

Atmospheric contamination by pesticides: Determination in the liquid, gaseous and particulate phases.

PubMed

Millet, M; Wortham, H; Sanusi, A; Mirabel, P

1997-01-01

Between 1991 and 1993, 18 fogwater samples, 31 rainwater samples and 17 atmosphere (gas and particles) samples were analysed for 13 pesticides (pp'DDT,pp'DDD,pp'DDE, aldrin, dieldrin, lindane, hexachlorobenzene, fenpropathrin, mecoprop, methyl-parathion, atrazine, isoproturon and aldicarb). The samples were collected in a rural area where some of the compounds are in use (experimental INRA farm, "Institut National de la Recherche Agronomique" in Colmar, Eastern France, 80,000 inhabitants). This paper briefly presents the analytical methodology used and, in detail, the contamination level of the different atmospheric phases. The contamination levels are roughly constant throughout the year in all the atmospheric phases and the most abundant pesticides are those commonly used on the experimental INRA farm and other surrounding farms. Nevertheless, some pesticides not used since the 1970s such as 1,1-Bis(4-chlorophenyl)-2,2,2-trichloroethane (pp'DDT) and 2,2-Bis(4-chlorophenyl)-1,1-dichloroethane (pp 'DDD) are also detected in the atmosphere of Colmar. A small increase in the pesticide concentrations in the atmosphere (gas and particles) was observed during treatments.

G-actin provides substrate-specificity to eukaryotic initiation factor 2α holophosphatases

PubMed Central

Chen, Ruming; Rato, Cláudia; Yan, Yahui; Crespillo-Casado, Ana; Clarke, Hanna J; Harding, Heather P; Marciniak, Stefan J; Read, Randy J; Ron, David

2015-01-01

Dephosphorylation of eukaryotic translation initiation factor 2a (eIF2a) restores protein synthesis at the waning of stress responses and requires a PP1 catalytic subunit and a regulatory subunit, PPP1R15A/GADD34 or PPP1R15B/CReP. Surprisingly, PPP1R15-PP1 binary complexes reconstituted in vitro lacked substrate selectivity. However, selectivity was restored by crude cell lysate or purified G-actin, which joined PPP1R15-PP1 to form a stable ternary complex. In crystal structures of the non-selective PPP1R15B-PP1G complex, the functional core of PPP1R15 made multiple surface contacts with PP1G, but at a distance from the active site, whereas in the substrate-selective ternary complex, actin contributes to one face of a platform encompassing the active site. Computational docking of the N-terminal lobe of eIF2a at this platform placed phosphorylated serine 51 near the active site. Mutagenesis of predicted surface-contacting residues enfeebled dephosphorylation, suggesting that avidity for the substrate plays an important role in imparting specificity on the PPP1R15B-PP1G-actin ternary complex. DOI: http://dx.doi.org/10.7554/eLife.04871.001 PMID:25774600

Metabolite identification and pharmacokinetic profiling of PP242, an ATP-competitive inhibitor of mTOR using ultra high-performance liquid chromatography and mass spectrometry.

PubMed

Rashid, Md Mamunur; Lee, Hyunbeom; Jung, Byung Hwa

2018-01-01

PP242 is a second generation novel selective ATP-competitive inhibitor of mTOR that displayed promising anti-cancer activity over several cancer types by inhibiting both the complexes of mTOR (mTORC1 and mTORC2). The purpose of this study is to identify the possible metabolites and to evaluate the pharmacokinetic profile of PP242 after a single oral administration to Sprague-Dawley (SD) rats. Two metabolites, including one phase I and one phase II, were identified by in vitro and in vivo studies using rat liver microsomes (RLMs) as well as rat plasma, urine and feces, respectively, through ultra high-performance liquid chromatography-linear ion trap quadrupole-orbitrap-mass spectrometry (UHPLC-LTQ-Orbitrap-MS). The major biotransformation pathways of PP242 were hydroxylation and glucuronide conjugation. Additionally, a simple and rapid quantification method was developed and validated. The method recovery was within 79.7-84.6%, whereas the matrix effect was 78.1-96.0% in all three quality control (QC) concentrations (low, medium and high) including the LLOQ. Other parameters showed acceptable results according to the US food and drug administration (FDA) guidelines for bioanalytical method validation. Afterwards, pharmacokinetic parameters were evaluated in rat plasma by successfully applying the validated method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). After a single oral administration at a dose of 5mg/kg, the maximum plasma concentration (C max ) of PP242 was 0.17±0.08μg/mL, while the elimination was moderately fast (T 1/2 : 172.18±45.54min). All of the obtained information on the metabolite identification and pharmacokinetic parameter elucidation could facilitate the further development of PP242. Copyright © 2017 Elsevier B.V. All rights reserved.

Low cardiorespiratory fitness and coronary artery calcification: Complementary cardiovascular risk predictors in asymptomatic type 2 diabetics.

PubMed

Zafrir, Barak; Azaiza, Mohanad; Gaspar, Tamar; Dobrecky-Mery, Idit; Azencot, Mali; Lewis, Basil S; Rubinshtein, Ronen; Halon, David A

2015-08-01

Despite its well-established prognostic value, cardiorespiratory fitness (CRF) is not incorporated routinely in risk assessment tools. Whether low CRF provides additional predictive information in asymptomatic type 2 diabetics beyond conventional risk scores and coronary artery calcification (CAC) is unclear. We studied 600 type 2 diabetics aged 55-74 years without known coronary heart disease. CRF was quantified in metabolic equivalents (METs) by maximal treadmill testing and categorized as tertiles of percent predicted METs (ppMETs) achieved. CAC was calculated by non-enhanced computed tomography scans. The individual and joint association of both measures with an outcome event of all-cause mortality, myocardial infarction or stroke, was determined over a mean follow-up period of 80 ± 16 months. There were 72 (12%) events during follow-up. Low CRF was independently associated with event risk after adjustment for traditional risk factors and CAC (HR 2.25, 95% CI 1.41-3.57, p = 0.001). CRF (unfit/fit) allowed further outcome discrimination both amongst diabetics with low CAC scores (9.5% versus 2.0% event rate), and amongst diabetics with high CAC scores (23.5% versus 12.4% event rate), p < 0.001. The addition of CRF to a model comprising UKPDS and CAC scores improved the area under the curve for event prediction from 0.66 to 0.71, p = 0.03, with a positive continuous net reclassification improvement (NRI) of 0.451, p = 0.002. CRF, quantified by ppMETs, provided independent prognostic information which was additive to CAC. Low CRF may identify asymptomatic diabetic subjects at higher risk for all-cause mortality, myocardial infarction or stroke, despite low CAC. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Altered expression levels of the protein phosphatase 2A ABalphaC enzyme are associated with Alzheimer disease pathology.

PubMed

Sontag, Estelle; Luangpirom, Ampa; Hladik, Christa; Mudrak, Ingrid; Ogris, Egon; Speciale, Samuel; White, Charles L

2004-04-01

The formation of amyloid-containing senile plaques and tau-rich neurofibrillary tangles are central events in Alzheimer disease (AD) pathogenesis. Significantly, ABalphaC, a major protein phosphatase 2A (PP2A) holoenzyme, specifically binds to and dephosphorylates tau. Deregulation of PP2A results in tau hyperphosphorylation in vivo. Here, we compared the expression levels and distribution of PP2A subunits in various brain regions from autopsy cases of AD and aged controls with or without histological evidence of age-related neurofibrillary degeneration. Immunoblotting analyses revealed that there was a significant reduction in the total amounts of ABalphaC in AD frontal and temporal cortices that matched the decrease in PP2A activity measured in the same brain homogenates. Immunohistochemical studies showed that neuronal ABalphaC expression levels were significantly and selectively decreased in AD-affected regions and in tangle-bearing neurons, but not in AD cerebellum and in non-AD dementias. Reduced neuronal ABalphaC immunoreactivity closely correlated with tangle load, but not plaque burden, suggesting that ABalphaC dysfunction contributes to AD tau pathology. Glial cells within senile plaques were also positive for ABalphaC. Increased glial PP2A immunoreactivity was observed in both AD and non-AD cases and may play a role in the brain's response to general inflammatory processes and amyloidogenesis.

Sodium pyrophosphate enhances iron bioavailability from bouillon cubes fortified with ferric pyrophosphate.

PubMed

Cercamondi, Colin I; Duchateau, Guus S M J E; Harika, Rajwinder K; van den Berg, Robin; Murray, Peter; Koppenol, Wieneke P; Zeder, Christophe; Zimmermann, Michael B; Moretti, Diego

2016-08-01

Fe fortification of centrally manufactured and frequently consumed condiments such as bouillon cubes could help prevent Fe deficiency in developing countries. However, Fe compounds that do not cause sensory changes in the fortified product, such as ferric pyrophosphate (FePP), exhibit low absorption in humans. Tetra sodium pyrophosphate (NaPP) can form soluble complexes with Fe, which could increase Fe bioavailability. Therefore, the aim of this study was to investigate Fe bioavailability from bouillon cubes fortified with either FePP only, FePP+NaPP, ferrous sulphate (FeSO4) only, or FeSO4+NaPP. We first conducted in vitro studies using a protocol of simulated digestion to assess the dialysable and ionic Fe, and the cellular ferritin response in a Caco-2 cell model. Second, Fe absorption from bouillon prepared from intrinsically labelled cubes (2·5 mg stable Fe isotopes/cube) was assessed in twenty-four Fe-deficient women, by measuring Fe incorporation into erythrocytes 2 weeks after consumption. Fe bioavailability in humans increased by 46 % (P<0·005) when comparing bouillons fortified with FePP only (4·4 %) and bouillons fortified with FePP+NaPP (6·4 %). Fe absorption from bouillons fortified with FeSO4 only and with FeSO4+NaPP was 33·8 and 27·8 %, respectively (NS). The outcome from the human study is in agreement with the dialysable Fe from the in vitro experiments. Our findings suggest that the addition of NaPP could be a promising strategy to increase Fe absorption from FePP-fortified bouillon cubes, and if confirmed by further research, for other fortified foods with complex food matrices as well.

Numerical simulations of PP-SESAME/Philae/ROSETTA operations during the Descent Phase and at the surface of the Churyumov-Gerasimenko nucleus

NASA Astrophysics Data System (ADS)

Lethuillier, Anthony; Hamelin, Michel; Le Gall, Alice; Caujolle-Bert, Sylvain; Schmidt, Walter; Grard, Réjean

2014-05-01

The ROSETTA probe has never been so close to its target; the comet Churyumov-Gerasimenko that it will reach later this year. Among the instruments on board the lander, Philae, the Permittivity Probe (PP) experiment, which is part of the Surface Electric Sounding and Acoustic Monitoring Experiment (SESAME) package, will measure the low frequency complex permittivity (i.e. dielectric constant and electrical conductivity) of the first 2 meters of the subsurface of the cometary nucleus. At frequencies below 10 kHz, the electrical signature of the matter is especially sensitive to the presence of water ice and its temperature behavior. PP will thus allow to determine the water ice content in the near-surface and to monitor its diurnal and orbital variations thus providing essential insight on the activity and evolution of the cometary nucleus. The PP instrument is based on the quadrupole array technique, which employs a set of transmitter and receiver electrodes for emitting alternating currents into a medium of interest. The complex permittivity of the cometary surface material is determined by measuring the magnitude and phase shift of both the emitted currents and the resulting potential difference at a pair of receiver electrodes. This technique has been used for many decades on Earth and recently helped to determine the electrical properties of the Huygens landing site on Titan (PWA/HASI experiment on Cassini-Huygens). In the case of PP, 5 electrodes can be used: 2 receiver electrodes are integrated into the lander feet while the transmitter electrodes are mounted on the third foot and on 2 other instruments. In this paper we will present results from numerical simulations performed in order to model PP operations and prepare the scientific return of this experiment. Though simple in theory, the inference of the complex permittivity from PP measurements is not straightforward in practice. In particular, the actual environment of the electrodes (lander body, feet, harpoons...) must be accounted for since the presence of nearby conducting objects will affect the data. We have thus developed a numerical model of the electrodes in their environment using COMSOL Multiphysics®. A simple version of this model was validated by comparison to laboratory measurements and analytical calculations. This model was then used to simulate PP operations during the Descent Phase of the lander (i.e. in the void and as the ground gets closer) and once at the surface of the nucleus considering different types of surfaces. The first set of simulations will be very useful to better understand the calibration data that will be acquired after separation from the ROSETTA Orbiter while the second will illustrate the idealistic sensitivity of PP to the ground electrical properties.

Toxicology of oxides of nitrogen. I. Toxic concentrations

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

La Towsky, L.W.; MacQuiddy, E.L.; Tollman, J.P.

1941-01-01

One hundred twelve rabbits, cats, guinea pigs, rats, and mice were exposed to 30 to 1000 ppM NO/sub 2/. Average time to produce death was: 30 ppM - none in 3 hr, 100 ppM - 318 min, 150 ppM - 90 min, 400 ppM - 58 min, 600 ppM - 32 min, 800 ppM - 29 min, 1000 ppM - 19 min. Rats and mice were more sensitive, sometimes exhibiting delayed effects (e.g., 2 to 3 hr at 55 ppM). Cats were most sensitive in that they thrash excitedly, thus breathing more. Methemoglobin was frequently seen in blood during exposure.more » Death was from edema (most common), asphyxia, or pneumonitis (secondary).« less

Chapter 2. Calcineurin signaling and the slow oxidative skeletal muscle fiber type.

PubMed

Mallinson, Joanne; Meissner, Joachim; Chang, Kin-Chow

2009-01-01

Calcineurin, also known as protein phosphatase 2B (PP2B), is a calcium-calmodulin-dependent phosphatase. It couples intracellular calcium to dephosphorylate selected substrates resulting in diverse biological consequences depending on cell type. In mammals, calcineurin's functions include neuronal growth, development of cardiac valves and hypertrophy, activation of lymphocytes, and the regulation of ion channels and enzymes. This chapter focuses on the key roles of calcineurin in skeletal muscle differentiation, regeneration, and fiber type conversion to an oxidative state, all of which are crucial to muscle development, metabolism, and functional adaptations. It seeks to integrate the current knowledge of calcineurin signaling in skeletal muscle and its interactions with other prominent regulatory pathways and their signaling intermediates to form a molecular overview that could provide directions for possible future exploitations in human metabolic health.

Random quaternary ammonium Diels-Alder poly(phenylene) copolymers for improved vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Largier, Timothy D.; Cornelius, Chris J.

2017-06-01

This study analyzes the effect of quaternary ammonium homopolymer (AmPP) and ionic and non-ionic random unit copolymerization (AmPP-PP) of Diels-Alder poly(phenylene)s on electrochemical and transport properties, vanadium redox flow battery performance, and material stability. AmPP-PP materials were synthesized with IEC's up to 2.2 meq/g, displaying a carbonate form ion conductivity of 17.3 mS/cm and water uptake of 57.3%. Vanadium ion permeability studies revealed that the random copolymers possess superior charge carrier selectivity. For materials of comparable ion content, at 10 mA/cm2 the random copolymer displayed a 14% increase in coulombic efficiency (CE) corresponding to a 7% increase in energy efficiency. All quaternary ammonium materials displayed ex situ degradation in a 0.5 M V5+ + 5 M H2SO4 solution, with the rate of degradation appearing to increase with IEC. Preliminary studies reveal that the neutralizing counter-ion has a significant effect on VRB performance, proportional to changes in vanadium ion molecular diffusion.

The bacterial alarmone (p)ppGpp activates the type III secretion system in Erwinia amylovora.

PubMed

Ancona, Veronica; Lee, Jae Hoon; Chatnaparat, Tiyakhon; Oh, Jinrok; Hong, Jong-In; Zhao, Youfu

2015-04-01

The hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS) is a key pathogenicity factor in Erwinia amylovora. Previous studies have demonstrated that the T3SS in E. amylovora is transcriptionally regulated by a sigma factor cascade. In this study, the role of the bacterial alarmone ppGpp in activating the T3SS and virulence of E. amylovora was investigated using ppGpp mutants generated by Red recombinase cloning. The virulence of a ppGpp-deficient mutant (ppGpp(0)) as well as a dksA mutant of E. amylovora was completely impaired, and bacterial growth was significantly reduced, suggesting that ppGpp is required for full virulence of E. amylovora. Expression of T3SS genes was greatly downregulated in the ppGpp(0) and dksA mutants. Western blotting showed that accumulations of the HrpA protein in the ppGpp(0) and dksA mutants were about 10 and 4%, respectively, of that in the wild-type strain. Furthermore, higher levels of ppGpp resulted in a reduced cell size of E. amylovora. Moreover, serine hydroxamate and α-methylglucoside, which induce amino acid and carbon starvation, respectively, activated hrpA and hrpL promoter activities in hrp-inducing minimal medium. These results demonstrated that ppGpp and DksA play central roles in E. amylovora virulence and indicated that E. amylovora utilizes ppGpp as an internal messenger to sense environmental/nutritional stimuli for regulation of the T3SS and virulence. The type III secretion system (T3SS) is a key pathogenicity factor in Gram-negative bacteria. Fully elucidating how the T3SS is activated is crucial for comprehensively understanding the function of the T3SS, bacterial pathogenesis, and survival under stress conditions. In this study, we present the first evidence that the bacterial alarmone ppGpp-mediated stringent response activates the T3SS through a sigma factor cascade, indicating that ppGpp acts as an internal messenger to sense environmental/nutritional stimuli for the regulation of the T3SS and virulence in plant-pathogenic bacteria. Furthermore, the recovery of an spoT null mutant, which displayed very unique phenotypes, suggested that small proteins containing a single ppGpp hydrolase domain are functional. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The Bacterial Alarmone (p)ppGpp Activates the Type III Secretion System in Erwinia amylovora

PubMed Central

Ancona, Veronica; Lee, Jae Hoon; Chatnaparat, Tiyakhon; Oh, Jinrok; Hong, Jong-In

2015-01-01

ABSTRACT The hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS) is a key pathogenicity factor in Erwinia amylovora. Previous studies have demonstrated that the T3SS in E. amylovora is transcriptionally regulated by a sigma factor cascade. In this study, the role of the bacterial alarmone ppGpp in activating the T3SS and virulence of E. amylovora was investigated using ppGpp mutants generated by Red recombinase cloning. The virulence of a ppGpp-deficient mutant (ppGpp0) as well as a dksA mutant of E. amylovora was completely impaired, and bacterial growth was significantly reduced, suggesting that ppGpp is required for full virulence of E. amylovora. Expression of T3SS genes was greatly downregulated in the ppGpp0 and dksA mutants. Western blotting showed that accumulations of the HrpA protein in the ppGpp0 and dksA mutants were about 10 and 4%, respectively, of that in the wild-type strain. Furthermore, higher levels of ppGpp resulted in a reduced cell size of E. amylovora. Moreover, serine hydroxamate and α-methylglucoside, which induce amino acid and carbon starvation, respectively, activated hrpA and hrpL promoter activities in hrp-inducing minimal medium. These results demonstrated that ppGpp and DksA play central roles in E. amylovora virulence and indicated that E. amylovora utilizes ppGpp as an internal messenger to sense environmental/nutritional stimuli for regulation of the T3SS and virulence. IMPORTANCE The type III secretion system (T3SS) is a key pathogenicity factor in Gram-negative bacteria. Fully elucidating how the T3SS is activated is crucial for comprehensively understanding the function of the T3SS, bacterial pathogenesis, and survival under stress conditions. In this study, we present the first evidence that the bacterial alarmone ppGpp-mediated stringent response activates the T3SS through a sigma factor cascade, indicating that ppGpp acts as an internal messenger to sense environmental/nutritional stimuli for the regulation of the T3SS and virulence in plant-pathogenic bacteria. Furthermore, the recovery of an spoT null mutant, which displayed very unique phenotypes, suggested that small proteins containing a single ppGpp hydrolase domain are functional. PMID:25666138

Ada (Trade Name) Bibliography. Volume 3.

DTIC Science & Technology

1986-02-01

EXPERIENCES IN TEACHING ADA CAVERLY. PHILIP ; DROCEA, CHARLES; GOLDSTEIN, PHILIP ; YEE, DONALD DOCUMENT NUMBER: 5523 TYPE: PAPER PROCEED. OF THE 2ND ANNUAL CONF...BABEL, PHILIP S. DOCUMENT NUMBER: b653 TYPE: PAPER WASHINGTON ADA SYMPOSIUM, 󈨘 MARCH, PP. 15-18 Motivated by the high cost of mission-critical...CLARA, CA 95052 3611 -01 HARDWARE COMES TO THE AID OF MODULAR HIGH-LEVEL LANGUAGES BABEL, PHILIPS ., U.S.A.F. ASD,WRIGHT-PATTERSON AFB, OH 5653 -03 JOINT

Sensitivity and symptomology of marigold cultivars exposed to acute sulfur dioxide

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

Howe, T.K.; Woltz, S.S.

Thirty-nine cultivars of marigold (Tagetes spp.) were exposed to sulfur dioxide to determine their relative sensitivity. Flowering plants were fumigated at 1 ppM SO/sub 2/ for 4 hours or at 2 ppM SO/sub 2/ for 2 hours. The average foliar injury for all leaves on individual plants ranged from 42.3% for 'Crackerjack Mix' at 2 ppM SO/sub 2/ to 0.0% for 'Cupid Yellow' at 1 ppM SO/sub 2/. Foliar necrosis appeared as a gray to white marginal and/or interveinal scorch 1 day after exposure. There was a tendency for interveinal necrosis to be near the midvein. The extra-floral nectaries whichmore » line the leaf margins of marigold were scorched in 15 of the 39 cultivars. This injury may be of diagnostic value. Sepals were very sensitive to SO/sub 2/. Sepal injury appeared as a pinpoint scorch and as tip burn, and was apparent in some cultivars when no foliar injury occurred. 12 references, 1 figure, 1 table.« less

Utilization of Industrial Waste for the Production of Bio-Preservative from Bacillus licheniformis Me1 and Its Application in Milk and Milk-Based Food Products.

PubMed

Nithya, Vadakedath; Prakash, Maya; Halami, Prakash M

2018-06-01

The bio-preservative efficacy of a partially purified antibacterial peptide (ppABP) produced by Bacillus licheniformis Me1 in an economical medium developed using agro-industry waste was evaluated by direct application in milk and milk-based food products. The addition of ppABP in milk samples stored at 4 ± 2 °C and 28 ± 2 °C resulted in the growth inhibition of pathogens Listeria monocytogenes Scott A, Micrococcus luteus ATCC 9341, and Staphylococcus aureus FRI 722. The shelf life of milk samples with added ppABP increased to 4 days at 28 ± 2 °C, whereas curdling and off-odor were noticed in samples without ppABP. Furthermore, the milk samples with ppABP were sensorily acceptable. Antilisterial effect was also observed in cheese and paneer samples treated with ppABP. These results clearly indicate that the ppABP of B. licheniformis Me1 can be utilized as a bio-preservative to control the growth of spoilage and pathogenic bacteria, thereby reducing the risk of food-borne diseases.

FTY720 inhibits mesothelioma growth in vitro and in a syngeneic mouse model.

PubMed

Szymiczek, Agata; Pastorino, Sandra; Larson, David; Tanji, Mika; Pellegrini, Laura; Xue, Jiaming; Li, Shuangjing; Giorgi, Carlotta; Pinton, Paolo; Takinishi, Yasutaka; Pass, Harvey I; Furuya, Hideki; Gaudino, Giovanni; Napolitano, Andrea; Carbone, Michele; Yang, Haining

2017-03-15

Malignant mesothelioma (MM) is a very aggressive type of cancer, with a dismal prognosis and inherent resistance to chemotherapeutics. Development and evaluation of new therapeutic approaches is highly needed. Immunosuppressant FTY720, approved for multiple sclerosis treatment, has recently raised attention for its anti-tumor activity in a variety of cancers. However, its therapeutic potential in MM has not been evaluated yet. Cell viability and anchorage-independent growth were evaluated in a panel of MM cell lines and human mesothelial cells (HM) upon FTY720 treatment to assess in vitro anti-tumor efficacy. The mechanism of action of FTY720 in MM was assessed by measuring the activity of phosphatase protein 2A (PP2A)-a major target of FTY720. The binding of the endogenous inhibitor SET to PP2A in presence of FTY720 was evaluated by immunoblotting and immunoprecipitation. Signaling and activation of programmed cell death were evaluated by immunoblotting and flow cytometry. A syngeneic mouse model was used to evaluate anti-tumor efficacy and toxicity profile of FTY720 in vivo. We show that FTY720 significantly suppressed MM cell viability and anchorage-independent growth without affecting normal HM cells. FTY720 inhibited the phosphatase activity of PP2A by displacement of SET protein, which appeared overexpressed in MM, as compared to HM cells. FTY720 promoted AKT dephosphorylation and Bcl-2 degradation, leading to induction of programmed cell death, as demonstrated by caspase-3 and PARP activation, as well as by cytochrome c and AIF intracellular translocation. Moreover, FTY720 administration in vivo effectively reduced tumor burden in mice without apparent toxicity. Our preclinical data indicate that FTY720 is a potentially promising therapeutic agent for MM treatment.

Longitudinal changes in late systolic cardiac load and serum NT-proBNP levels in healthy middle-aged Japanese men.

PubMed

Tomiyama, Hirofumi; Nishikimi, Toshio; Matsumoto, Chisa; Kimura, Kazutaka; Odaira, Mari; Shiina, Kazuki; Yamashina, Akira

2015-04-01

We determined whether any significant association exists between change in late systolic cardiac load with time, estimated by radial pressure waveform analysis, and development of cardiac hemodynamic stress in individuals with preserved cardiac function. Brachial-ankle pulse wave velocity, radial augmentation index (rAI), first peak of the radial pressure waveform (SP1), systolic and pulse pressure at the second peak of the radial pressure waveform (SP2 and PP2), and serum levels of N-terminal fragment B-type natriuretic peptide (NT-proBNP) were measured at the start (first examination) and at the end (second examination) of this 3-year study in healthy Japanese men (n = 1,851). A stepwise multivariate linear regression analysis demonstrated that among the parameters of radial pressure waveform analysis and markers of arterial stiffness analyzed, only PP2 was significantly associated with serum NT-proBNP levels in study participants at both the first and second examinations. Furthermore, among the parameters analyzed, only change in PP2 was significantly correlated with the change in serum NT-proBNP levels during the study period (beta = 0.131, P < 0.001). Sustained late systolic cardiac load might be a more significant determinant of the development of cardiac hemodynamic stress than sustained early systolic cardiac load or arterial stiffening in individuals with preserved cardiac function. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Development of a F actin-based live-cell fluorimetric microplate assay for diarrhetic shellfish toxins.

PubMed

Leira, F; Alvarez, C; Cabado, A G; Vieites, J M; Vieytes, M R; Botana, L M

2003-06-15

A new cytotoxicity assay for detection and quantitation of diarrhetic shellfish toxins (DSP) is presented. This assay is based upon fluorimetric determination of F-actin depolymerization induced by okadaic acid (OA)-class compounds in the BE(2)-M17 neuroblastoma cell line. No interferences were observed with other marine toxins such as saxitoxin, domoic acid, or yessotoxin, thus indicating a good specificity of the assay as expected by the direct relationship between protein phosphatase inhibition and cytoskeletal changes. The proposed method is rapid (<2h) and shows a linear response in the range of 50-300 nM OA. The detection limit of the assay for crude methanolic extracts of bivalves lies between 0.2 and 1.0 microg OA per gram of digestive glands, depending on the type of samples (fresh or canned), thus being similar to that of the mouse bioassay. The performance of this assay has been evaluated by comparative analysis of 32 toxic mussel samples by the F-actin assay, mouse bioassay, HPLC and PP2A inhibition assay. Results obtained by the F-actin method showed no differences with HPLC and significant correlation with PP2A inhibition assay (r(2)=0.71). No false negative results were obtained with this new cell assay, which also showed optimum reproducibility.

Closed-Loop Control of Postprandial Glycemia Using an Insulin-on-Board Limitation Through Continuous Action on Glucose Target.

PubMed

Rossetti, Paolo; Quirós, Carmen; Moscardó, Vanessa; Comas, Anna; Giménez, Marga; Ampudia-Blasco, F Javier; León, Fabián; Montaser, Eslam; Conget, Ignacio; Bondia, Jorge; Vehí, Josep

2017-06-01

Postprandial (PP) control remains a challenge for closed-loop (CL) systems. Few studies with inconsistent results have systematically investigated the PP period. To compare a new CL algorithm with current pump therapy (open loop [OL]) in the PP glucose control in type 1 diabetes (T1D) subjects. A crossover randomized study was performed in two centers. Twenty T1D subjects (F/M 13/7, age 40.7 ± 10.4 years, disease duration 22.6 ± 9.9 years, and A1c 7.8% ± 0.7%) underwent an 8-h mixed meal test on four occasions. In two (CL1/CL2), after meal announcement, a bolus was given followed by an algorithm-driven basal infusion based on continuous glucose monitoring (CGM). Alternatively, in OL1/OL2 conventional pump therapy was used. Main outcome measures were as follows: glucose variability, estimated with the coefficient of variation (CV) of the area under the curve (AUC) of plasma glucose (PG) and CGM values, and from the analysis of the glucose time series; mean, maximum (C max ), and time to C max glucose concentrations and time in range (<70, 70-180, >180 mg/dL). CVs of the glucose AUCs were low and similar in all studies (around 10%). However, CL achieved greater reproducibility and better PG control in the PP period: CL1 = CL2 0.05) nor the need for oral glucose was significantly different (CL 40.0% vs. OL 22.5% of meals; P = 0.054). This novel CL algorithm effectively and consistently controls PP glucose excursions without increasing hypoglycemia. Study registered at ClinicalTrials.gov : study number NCT02100488.

Purification and characterization of protein phosphatase 2A from petals of the tulip Tulipa gesnerina.

PubMed

Azad, Md Abul Kalam; Sawa, Yoshihiro; Ishikawa, Takahiro; Shibata, Hitoshi

2006-11-30

The holoenzyme of protein phosphatase (PP) from tulip petals was purified by using hydrophobic interaction, anion exchange and microcystin affinity chromatography to analyze activity towards p-nitrophenyl phosphate (p-NPP). The catalytic subunit of PP was released from its endogenous regulatory subunits by ethanol precipitation and further purified. Both preparations were characterized by immunological and biochemical approaches to be PP2A. On SDS-PAGE, the final purified holoenzyme preparation showed three protein bands estimated at 38, 65, and 75 kDa while the free catalytic subunit preparation showed only the 38 kDa protein. In both preparations, the 38 kDa protein was identified immunologically as the catalytic subunit of PP2A by using a monoclonal antibody against the PP2A catalytic subunit. The final 623- and 748- fold purified holoenzyme and the free catalytic preparations, respectively, exhibited high sensitivity to inhibition by 1 nM okadaic acid when activity was measured with p-NPP. The holoenzyme displayed higher stimulation in the presence of ammonium sulfate than the free catalytic subunit did by protamine, thereby suggesting different enzymatic behaviors.

Effect of dinucleoside pyrophosphates on the oligomerization of activated mononucleotides on Na(+)-montmorillonite: reaction of 5'-phosphoro-4-(dimethylamino)pyridinium [4-(CH3)2NpypA] with A5'ppA

NASA Technical Reports Server (NTRS)

Prabahar, K. J.; Ferris, J. P.

1997-01-01

The oligomerization of adenosine 5'-phosphoro-4-(dimethylamino)pyridinium (4-(CH3)2-NpypA) and diadenosine 5',5'-pyrophosphate (A5'ppA) (9:1) on Na(+)-montmorillonite was studied. The oligomers were isolated and analyzed by selective enzymatic hydrolyses and the oligomeric composition and the percent of 3',5'-phosphodiester linkages present in each fraction was determined. The longest oligomers formed (11-mers) are slightly shorter than those produced in the absence of A5'ppA (12-mers). Smaller amounts of A5'ppA are incorporated into the oligomers than in the ImpA/A5'ppA reaction. The regioselectivity of 3',5'-phosphodiester bond formation is comparable to that of the oligomerization of 4-(CH3)2NpypA alone. An explanation of these data is proposed and the possible effect of dinucleoside pyrophosphate on prebiotic RNA formation is discussed.

Measuring rare and exclusive Higgs boson decays into light resonances

NASA Astrophysics Data System (ADS)

Chisholm, Andrew S.; Kuttimalai, Silvan; Nikolopoulos, Konstantinos; Spannowsky, Michael

2016-09-01

We evaluate the LHC's potential of observing Higgs boson decays into light elementary or composite resonances through their hadronic decay channels. We focus on the Higgs boson production processes with the largest cross sections, pp → h and pp → h+{jet}, with subsequent decays h → ZA or h → Z η _c, and comment on the production process pp → hZ. By exploiting track-based jet substructure observables and extrapolating to 3000 {fb}^{-1} we find {BR}(h → ZA) ≃ {BR}(h → Z η _c) ≲ 0.02 at 95 % CL. We interpret this limit in terms of the 2HDM Type 1. We find that searches for h→ ZA are complementary to existing measurements and can constrain large parts of the currently allowed parameter space.

Egr1 Target Genes That Regulate Growth/Survival of Prostate Cells

DTIC Science & Technology

2005-03-01

led to the followed by immunoprecipitation with antibodies to Egrl following study that defined the role of Egrl in prostate (ChIP). To detect...with UV-C (40 J/Mr) were chromatin crosslinked and then immuntoprecipitated with a specific Egri antibody (rE) or a nonimmune control IgG antibody [aN...86 A 󈧬 Mi2 B him . Figure 2. C8P/p300 Are Upregulated by Egrl 120 serum 0 1 2 3 0 1 in Serum-Induced Prostate Cells and in Wild- 10o -4-.cRP PM Type

Yersinia enterocolitica YopH-Deficient Strain Activates Neutrophil Recruitment to Peyer's Patches and Promotes Clearance of the Virulent Strain.

PubMed

Dave, Mabel N; Silva, Juan E; Eliçabe, Ricardo J; Jeréz, María B; Filippa, Verónica P; Gorlino, Carolina V; Autenrieth, Stella; Autenrieth, Ingo B; Di Genaro, María S

2016-11-01

Yersinia enterocolitica evades the immune response by injecting Yersinia outer proteins (Yops) into the cytosol of host cells. YopH is a tyrosine phosphatase critical for Yersinia virulence. However, the mucosal immune mechanisms subverted by YopH during in vivo orogastric infection with Y. enterocolitica remain elusive. The results of this study revealed neutrophil recruitment to Peyer's patches (PP) after infection with a YopH-deficient mutant strain (Y. enterocolitica ΔyopH). While the Y. enterocolitica wild-type (WT) strain in PP induced the major neutrophil chemoattractant CXCL1 mRNA and protein levels, infection with the Y. enterocolitica ΔyopH mutant strain exhibited a higher expression of the CXCL1 receptor, CXCR2, in blood neutrophils, leading to efficient neutrophil recruitment to the PP. In contrast, migration of neutrophils into PP was impaired upon infection with Y. enterocolitica WT strain. In vitro infection of blood neutrophils revealed the involvement of YopH in CXCR2 expression. Depletion of neutrophils during Y. enterocolitica ΔyopH infection raised the bacterial load in PP. Moreover, the clearance of WT Y. enterocolitica was improved when an equal mixture of Y. enterocolitica WT and Y. enterocolitica ΔyopH strains was used in infecting the mice. This study indicates that Y. enterocolitica prevents early neutrophil recruitment in the intestine and that the effector protein YopH plays an important role in the immune evasion mechanism. The findings highlight the potential use of the Y. enterocolitica YopH-deficient strain as an oral vaccine carrier. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Gene-specific regulation of hepatic selenoprotein expression by interleukin-6.

PubMed

Martitz, J; Becker, N-P; Renko, K; Stoedter, M; Hybsier, S; Schomburg, L

2015-11-01

Sepsis is a severe inflammatory disease resulting in excessive production of pro-inflammatory cytokines including interleukin-6 (IL-6), causing oxidative stress, tissue damage and organ dysfunction. Health benefits have been observed upon selenium (Se) supplementation in severe sepsis. Selenium is incorporated into selenoproteins implicated in anti-oxidative defence, thyroid hormone metabolism and immunoregulation. Selenium metabolism is controlled by hepatocytes synthesizing and secreting the Se transporter selenoprotein P (SePP). The circulating SePP declines in sepsis causing low serum Se levels. Dysregulation of the hepatic selenoenzyme deiodinase type 1 (DIO1) potentially contributes to the low T3 (thyroid hormone) syndrome observed in severe diseases. We hypothesized that IL-6 affects hepatic selenoprotein biosynthesis directly. Testing human hepatocytes in culture, IL-6 reduced the concentrations of SePP mRNA and secreted SePP in a dose-dependent manner. In parallel, expression of DIO1 declined at the mRNA, protein and enzyme activity level. The effects of IL-6 on glutathione peroxidase (GPX) expression were isozyme-specific; GPX1 remained unaffected, while transcript concentrations of GPX2 increased and those of GPX4 decreased. This pattern of IL-6-dependent effects was mirrored in reporter gene experiments with SePP, DIO1, GPX1, and GPX2 promoter constructs pointing to direct transcriptional effects of IL-6. The redirection of hepatic selenoprotein biosynthesis by IL-6 may represent a central regulatory circuit responsible for the decline of serum Se and low T3 concentrations in sepsis. Accordingly, therapeutic IL-6 targeting may be effective for improving the Se and thyroid hormone status, adjuvant Se supplementation success and survival in sepsis.

A First Cut at Doctrine for Automation of Division Command and Control.

DTIC Science & Technology

1985-12-02

34MSE: Mobile Subscriber Equipmentd," Arm-Y Communicator (Fall 1984), pp. 6-22. 20. Anthony L. Borelli and LTC Raymond J. Leopold, "Enhanced JTIDS: High...three, 1985. I’- pp. 85-8,. Berceau, CPT Stan. "ASAS." C2MUG Bulletin. September 1965, pp. 1-2. Borelli , Anthony L. and Leopold, LTC Raymond J

Stability of a secondary-type recovery process

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

Jones, S.C.

1970-04-21

To provide good mobility control and to protect the components of the micellar dispersion displacing fluid from ''leaching'' into the drive fluid (water), the front portion of the drive fluid contained a mobility reducing agent, an electrolyte, and a semipolar organic compound. Berea sandstone cores (20.2 percent porosity, 336 md permeability) were saturated with water from Henry lease in Illinois (18,000 ppM TDS), flooded with sweet black crude oil (7 cp at 72/sup 0/F) from the Henry lease, and waterflooded with Henry lease water. A recovery of 93.9 percent of original oil in place was obtained by a micellar dispersionmore » followed by the mobility buffer. The micellar dispersion contained ammonium petroleum sulfonate, crude column overhead (a heavy naptha), isopropanol, p-nonyl phenol, water and sodium hydroxide. No. 530 Pusher, water from the Palestine water reservoir in Palestine, Illinois (450 ppM TDS), 50 ppM ammonium thiocyanate, n-butanol, and isopropyl alcohol (to facilitate the solubilization of the polymer) were in the mobility buffer.« less

Stability of a secondary-type recovery process

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

Jones, S.C.

1970-07-14

To provide good mobility control and to protect the components of the micellar dispersion displacing fluid from ''leaching'' into the drive fluid (water), the front portion of the drive fluid contained a mobility reducing agent, an electrolyte, and a semipolar organic compound. Berea sandstone cores (20.2 percent porosity, 336 md permeability) were saturated with water from Henry lease in Illinois (18,000 ppM TDS), flooded with sweet black crude oil (7 cp at 72/sup 0/F) from the Henry lease, and waterflooded with Henry lease water. A recovery of 93.9 percent of original oil in place was obtained by a micellar dispersionmore » followed by the mobility buffer. The micellar dispersion contained ammonium petroleum sulfonate, crude column overhead (a heavy naptha), isopropanol, p-nonyl phenol, water and sodium hydroxide. No. 530 Pusher, water from the Palestine water reservoir in Palestine, Illinois (450 ppM TDS), 50 ppM ammonium thiocyanate, n-butanol, and isopropyl alcohol (to facilitate the solubilization of the polymer) were in the mobility buffer.« less

8/8 and 10/10 high-resolution match rate for the be the match unrelated donor registry.

PubMed

Dehn, Jason; Buck, Kelly; Maiers, Martin; Confer, Dennis; Hartzman, Robert; Kollman, Craig; Schmidt, Alexander H; Yang, Soo Young; Setterholm, Michelle

2015-01-01

The National Marrow Donor Program's Be The Match Registry(®) facilitates the worldwide utilization of unrelated donor (URD) grafts for patients in need of a hematopoietic cell transplantation. In this study, we estimate the URD match rate for patients of White (WH), Hispanic (HIS), Asian/Pacific Islander (API), and African American/Black (AFA) race and ethnic groups. We chose 1344 URD at random as "pseudo-patients" (PP) to estimate the likelihood of finding an 8/8 or 10/10 high-resolution HLA-A,-B,-C,-DRB1 (and -DQB1) matched URD. Searches were conducted in the Be The Match Registry database for each PP at 2 time points: 2009 and 2012. URD who were a potential match for a PP by low/intermediate resolution were HLA typed by sequence-based typing to resolve the matching status. The 8/8 match rate for WH PP improved from 68% in 2009 to 72% in 2012. Corresponding match rates were 41% to 44% for HIS, 44% to 46% for API, and 27% to 30% for AFA, for 2009 and 2012, respectively. The 2012 10/10 match rates were 67% for WH, 38% for HIS, 41% for API, and 23% for AFA. These results provide baseline 8/8 and 10/10 match rate estimates by race for patients seeking an URD. Copyright © 2015 American Society for Blood and Marrow Transplantation. All rights reserved.

The Relationship Between Pulse Pressure, the Estimated Glomerular Filtration Rate, and Urine Microalbumin/Creatinine Ratio in Korean Adults.

PubMed

Seong, Jeong Min; Park, Chang Eun; Gi, Mi Young; Sun, Kwang Soon; Kim, Yu Jeong; Yoon, Hyun

2017-01-01

Pulse pressure (PP) is a predictor of adverse outcomes in patients on haemodialysis. Thus, the present study was conducted to assess the relationship between PP, estimated glomerular filtration rate (eGFR), and urine microalbumin/creatinine ratio (uACR) in Korean adults. Data of 9,409 adults (4,206 men and 5,203 women) aged ≥ 20 years from the Sixth Korean National Health and Nutrition Examination Survey (2013-2014) were analyzed. A multivariate analysis revealed that systolic blood pressure (SBP) (β = -0.170, 95% confidence interval [CI], -0.216 to -0.159), diastolic blood pressure (DBP) (β = 0.088, 95% CI 0.108-0.200; p < 0.001), and PP (β = -0.134, 95% CI -0.215 to -0.157) were significant factors determining eGFR. In contrast, SBP (β = 0.152, 95% CI, 0.985-1.456; p < 0.001), DBP (β = -0.062, 95% CI -1.141 to -0.442; p < 0.001), and PP (β = 0.118, 95% CI 0.965-1.436; p < 0.001) were the significant factors determining uACR. The odds ratios (ORs) of a high PP (PP ≥ 60 mmHg) with a normal group [eGFR ≥ 60 ml/min/1.73 m2 and uACR < 30 mg/g] as a reference were significant for decreased eGFR [eGFR < 60 ml/min/1.73 m2, 1.484 (95% CI, 1.003-2.196)], elevated uACR [uACR ≥ 30 mg/g, 2.592 (95% CI, 2.085-3.223)], and decreased eGFR plus elevated uACR [eGFR < 60 ml/min/1.73 m2 and uACR ≥ 30 mg/g, 3.889 (95% CI, 2.519-6.004)]. Enhanced PP was associated with a decreased eGFR and an increase in uACR in Korean adults. In addition, the PP increased greatly when a decrease in eGFR and an increase in uACR appeared simultaneously. © 2017 The Author(s). Published by S. Karger AG, Basel.

Role of MRI T2-DRIVE in the assessment of pituitary stalk abnormalities without gadolinium in pituitary diseases.

PubMed

Godano, Elisabetta; Morana, Giovanni; Di Iorgi, Natascia; Pistorio, Angela; Allegri, Anna Elsa Maria; Napoli, Flavia; Gastaldi, Roberto; Calcagno, Annalisa; Patti, Giuseppa; Gallizia, Annalisa; Notarnicola, Sara; Giaccardi, Marta; Noli, Serena; Severino, Mariasavina; Tortora, Domenico; Rossi, Andrea; Maghnie, Mohamad

2018-06-01

To investigate the role of T2-DRIVE MRI sequence in the accurate measurement of pituitary stalk (PS) size and the identification of PS abnormalities in patients with hypothalamic-pituitary disorders without the use of gadolinium. This was a retrospective study conducted on 242 patients who underwent MRI due to pituitary dysfunction between 2006 and 2015. Among 135 eligible patients, 102 showed eutopic posterior pituitary (PP) gland and 33 showed 'ectopic' PP (EPP). Two readers independently measured the size of PS in patients with eutopic PP at the proximal, midpoint and distal levels on pre- and post-contrast T1-weighted as well as T2-DRIVE images; PS visibility was assessed on pre-contrast T1 and T2-DRIVE sequences in those with EPP. The length, height, width and volume of the anterior pituitary (AP), PP height and length and PP area were analyzed. Significant agreement between the two readers was obtained for T2-DRIVE PS measurements in patients with 'eutopic' PP; a significant difference was demonstrated between the intraclass correlation coefficient calculated on the T2-DRIVE and the T1-pre- and post-contrast sequences. The percentage of PS identified by T2-DRIVE in EPP patients was 72.7% compared to 30.3% of T1 pre-contrast sequences. A significant association was found between the visibility of PS on T2-DRIVE and the height of AP. T2-DRIVE sequence is extremely precise and reliable for the evaluation of PS size and the recognition of PS abnormalities; the use of gadolinium-based contrast media does not add significant information and may thus be avoided. © 2018 European Society of Endocrinology.

Effect of ethanol on hydrogen peroxide-induced AMPK phosphorylation.

PubMed

Liangpunsakul, Suthat; Wou, Sung-Eun; Zeng, Yan; Ross, Ruth A; Jayaram, Hiremagalur N; Crabb, David W

2008-12-01

AMP-activated protein kinase (AMPK) responds to oxidative stress. Previous work has shown that ethanol treatment of cultured hepatoma cells and of mice inhibited the activity of AMPK and reduced the amount of AMPK protein. Ethanol generates oxidative stress in the liver. Since AMPK is activated by reactive oxygen species, it seems paradoxical that ethanol would inhibit AMPK in the hepatoma cells. In an attempt to understand the mechanism whereby ethanol inhibits AMPK, we studied the effect of ethanol on AMPK activation by exogenous hydrogen peroxide. The effects of ethanol, hydrogen peroxide, and inhibitors of protein phosphatase 2A (PP2A) [either okadaic acid or PP2A small interference RNA (siRNA)] on AMPK phosphorylation and activity were examined in rat hepatoma cells (H4IIEC3) and HeLa cells. In H4IIEC3 cells, hydrogen peroxide (H(2)O(2), 1 mM) transiently increased the level of phospho-AMPK to 1.5-fold over control (P < 0.05). Similar findings were observed in HeLa cells, which do not express the upstream AMPK kinase, LKB1. H(2)O(2) markedly increased the phosphorylation of LKB1 in H4IIEC3 cells. Ethanol significantly inhibited the phosphorylation of PKC-zeta, LKB1, and AMPK caused by exposure to H(2)O(2). This inhibitory effect of ethanol required its metabolism. More importantly, the inhibitory effects of ethanol on H(2)O(2)-induced AMPK phosphorylation were attenuated by the presence of the PP2A inhibitor, okadaic acid, or PP2A siRNA. The inhibitory effect of ethanol on AMPK phosphorylation is exerted through the inhibition of PKC-zeta and LKB1 phosphorylation and the activation of PP2A.

Intermittent Induction of HIF-1α Produces Lasting Effects on Malignant Progression Independent of Its Continued Expression

PubMed Central

Choi, Hyunsung; Gillespie, David L.; Berg, Shauna; Rice, Christopher; Couldwell, Sandrine; Gu, Jie; Colman, Howard; Jensen, Randy L.; Huang, L. Eric

2015-01-01

Dysregulation of hypoxia-inducible transcription factors HIF-1α and HIF-2α correlates with poor prognosis in human cancers; yet, divergent and sometimes opposing activities of these factors in cancer biology have been observed. Adding to this complexity is that HIF-1α apparently possesses tumor-suppressing activities, as indicated by the loss-of-function mutations or even homozygous deletion of HIF1A in certain human cancers. As a step towards understanding this complexity, we employed 8-week intermittent induction of a stable HIF-1α variant, HIF1α(PP), in various cancer cell lines and examined the effects on malignant progression in xenografts of immunocompromised mice in comparison to those of HIF2α(PP). Although 8-week treatment led to eventual loss of HIF1α(PP) expression, treated osteosarcoma U-2 OS cells acquired tumorigenicity in the subcutaneous tissue. Furthermore, the prior treatment resulted in widespread invasion of malignant glioma U-87 MG cells in the mouse brain and sustained growth of U-118 MG glioma cells. The lasting effects of HIF-1α on malignant progression are specific because neither HIF2α(PP) nor β-galactosidase yielded similar effects. By contrast, transient expression of HIF1α(PP) in U-87 MG cells or constitutive expression of HIF1α(PP) but not HIF2α(PP) in a patient-derived glioma sphere culture inhibited tumor growth and spread. Our results indicate that intermittent induction of HIF-1α produces lasting effects on malignant progression even at its own expense. PMID:25893706

Parameters Comparsion of Leads Detection in Arctic Sea Ice Using CRYOSAT-2 Waveform Data

NASA Astrophysics Data System (ADS)

Li, J.; Zhang, S.; Xiao, F.; Zhu, C.; Zhang, Y.; Zhu, T.; Yuan, L.

2018-04-01

Leads are only a small part of the polar sea ice structure, but they play a dominant role on the turbulence exchange between the ocean and the atmosphere, they are also important factors about sea ice thickness inversion. Since the early 2000s, Satellite altimetry has been applied to monitor the Arctic sea ice thickness, Satellite altimetry data can be used to distinguish leads and sea ice. In this paper, four parameters including Pulse peakiness (PP), stack standard deviation (SSD), stack kurtosis (SKU) and stack skewness (SSK) are extracted from CryoSat-2 satellite altimetry waveform data. The four parameters are combined into five combinations (PP, PP&SSD, PP&SSD&SKU, PP&SSD&SSK, PP&SSD&SSK&SKU) with constrain conditions to detect the leads. The results of the five methods are compared with MODIS (moderate-resolution imagining spectroradiometer) images and show that, the combination of PP&SSD is better than the single PP, the rest of combinations are the same as the combination of PP&SSD. It turns out, there is no promotion when we add SSK and SKU, successively or simultaneously.

Relative Proper Motions in the Rho Ophiuchi Cluster

DTIC Science & Technology

2016-01-06

not limited in sensitivity, like infrared radial velocity surveys, due to the high extinctions and veiling. The Astrophysical Journal, 815:2 (10pp...Cores C-S, E 16 4 16:26:08.2 −24:22:45 Core A-3 16 Note. a Core designations following Motte et al. (1998). 2 The Astrophysical Journal, 815:2 (10pp

Efficient cluster-based catalysts for asymmetric hydrogenation of α-unsaturated carboxylic acids.

PubMed

Moberg, Viktor; Duquesne, Robin; Contaldi, Simone; Röhrs, Oliver; Nachtigall, Jonny; Damoense, Llewellyn; Hutton, Alan T; Green, Michael; Monari, Magda; Santelia, Daniela; Haukka, Matti; Nordlander, Ebbe

2012-09-24

The new clusters [H(4)Ru(4)(CO)(10)(μ-1,2-P-P)], [H(4)Ru(4)(CO)(10) (1,1-P-P)] and [H(4)Ru(4)(CO)(11)(P-P)] (P-P=chiral diphosphine of the ferrocene-based Josiphos or Walphos ligand families) have been synthesised and characterised. The crystal and molecular structures of eleven clusters reveal that the coordination modes of the diphosphine in the [H(4)Ru(4)(CO)(10)(μ-1,2-P-P)] clusters are different for the Josiphos and the Walphos ligands. The Josiphos ligands bridge a metal-metal bond of the ruthenium tetrahedron in the "conventional" manner, that is, with both phosphine moieties coordinated in equatorial positions relative to a triangular face of the tetrahedron, whereas the phosphine moieties of the Walphos ligands coordinate in one axial and one equatorial position. The differences in the ligand size and the coordination mode between the two types of ligands appear to be reflected in a relative propensity for isomerisation; in solution, the [H(4)Ru(4)(CO)(10)(1,1-Walphos)] clusters isomerise to the corresponding [H(4)Ru(4)(CO)(10)(μ-1,2-Walphos)] clusters, whereas the Josiphos-containing clusters show no tendency to isomerisation in solution. The clusters have been tested as catalysts for asymmetric hydrogenation of four prochiral α-unsaturated carboxylic acids and the prochiral methyl ester (E)-methyl 2-methylbut-2-enoate. High conversion rates (>94%) and selectivities of product formation were observed for almost all catalysts/catalyst precursors. The observed enantioselectivities were low or nonexistent for the Josiphos-containing clusters and catalyst (cluster) recovery was low, suggesting that cluster fragmentation takes place. On the other hand, excellent conversion rates (99-100%), product selectivities (99-100% in most cases) and good enantioselectivities, reaching 90% enantiomeric excess (ee) in certain cases, were observed for the Walphos-containing clusters, and the clusters could be recovered in good yield after completed catalysis. Results from high-pressure NMR and IR studies, catalyst poisoning tests and comparison of catalytic properties of two [H(4)Ru(4)(CO)(10)(μ-1,2-P-P)] clusters (P-P=Walphos ligands) with the analogous mononuclear catalysts [Ru(P-P)(carboxylato)(2)] suggest that these clusters may be the active catalytic species, or direct precursors of an active catalytic cluster species. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Field comparison of air sampling methods for monomeric and polymeric 1,6-hexamethylene diisocyanate.

PubMed

Thomasen, Jennifer M; Fent, Kenneth W; Reeb-Whitaker, Carolyn; Whittaker, Stephen G; Nylander-French, Leena A

2011-03-01

This study was to critically compared 13 different air samplers for their ability to monitor air exposures to monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI) in the automotive refinishing industry. Using both fast- and slow-drying clearcoat, we tested the following types of samplers: single- and dual-stage 37-mm polypropylene (PP) and polystyrene (PS) samplers (open- and closed-face), IOM (with plastic and stainless steel inserts), OSHA42, IsoChek, and WA-DOSH samplers. Midget impingers with frit were used as reference samplers. We observed the PP, PS, and IOM samplers to measure greater levels of HDI monomer and biuret when a fast-drying clearcoat was applied compared with a slow-drying clearcoat. When a slow-drying clearcoat was applied, the open-face PP and PS samplers measured significantly more monomeric and polymeric HDI (2-fold; p < 0.003) than the closed-face PP and PS samplers. We determined that significantly more monomeric and polymeric HDI were measured by impingers (1.3-1.9-fold) compared with single-stage PP/PS (N = 59), dual-stage PP/PS (N = 59), or IOM (N = 24) samplers. However, when stratified by cassette characteristics, the open-face single-stage PP and PS samplers performed equally to the impingers for HDI monomer when a fast-drying clearcoat was applied, and for all analytes when a slow-drying clearcoat was applied. Significantly higher HDI monomer concentrations (1.2-3.1-fold; p = 0.001) were measured with OSHA42 compared with the impinger. The IsoChek did not detect HDI monomer, and of the three samplers analyzed by laboratories other than UNC (i.e., OSHA42, IsoChek, and WA-DOSH), the WA-DOSH was in the best agreement with the impingers. The influence of clearcoat drying time on the sampler's ability to measure monomeric and polymeric HDI emphasizes the importance of the speciation of diisocyanates in chemical analysis and the careful consideration for the selection of the air sampler to be used when measuring exposures during automotive spray painting.

Heteroleptic copper(I) complexes prepared from phenanthroline and bis-phosphine ligands.

PubMed

Kaeser, Adrien; Mohankumar, Meera; Mohanraj, John; Monti, Filippo; Holler, Michel; Cid, Juan-José; Moudam, Omar; Nierengarten, Iwona; Karmazin-Brelot, Lydia; Duhayon, Carine; Delavaux-Nicot, Béatrice; Armaroli, Nicola; Nierengarten, Jean-François

2013-10-21

Preparation of [Cu(NN)(PP)](+) derivatives has been systematically investigated starting from two libraries of phenanthroline (NN) derivatives and bis-phosphine (PP) ligands, namely, (A) 1,10-phenanthroline (phen), neocuproine (2,9-dimethyl-1,10-phenanthroline, dmp), bathophenanthroline (4,7-diphenyl-1,10-phenanthroline, Bphen), 2,9-diphenethyl-1,10-phenanthroline (dpep), and 2,9-diphenyl-1,10-phenanthroline (dpp); (B) bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)benzene (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppFc), and bis[(2-diphenylphosphino)phenyl] ether (POP). Whatever the bis-phosphine ligand, stable heteroleptic [Cu(NN)(PP)](+) complexes are obtained from the 2,9-unsubstituted-1,10-phenanthroline ligands (phen and Bphen). By contrast, heteroleptic complexes obtained from dmp and dpep are stable in the solid state, but a dynamic ligand exchange reaction is systematically observed in solution, and the homoleptic/heteroleptic ratio is highly dependent on the bis-phosphine ligand. Detailed analysis revealed that the dynamic equilibrium resulting from ligand exchange reactions is mainly influenced by the relative thermodynamic stability of the different possible complexes. Finally, in the case of dpp, only homoleptic complexes were obtained whatever the bis-phosphine ligand. Obviously, steric effects resulting from the presence of the bulky phenyl rings on the dpp ligand destabilize the heteroleptic [Cu(NN)(PP)](+) complexes. In addition to the remarkable thermodynamic stability of [Cu(dpp)2]BF4, this negative steric effect drives the dynamic complexation scenario toward almost exclusive formation of homoleptic [Cu(NN)2](+) and [Cu(PP)2](+) complexes. This work provides the definitive rationalization of the stability of [Cu(NN)(PP)](+) complexes, marking the way for future developments in this field.

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

Patterson, D.T.; Flint, E.P.

Research report: Mathematical growth analysis techniques were used to determine the effects of carbon dioxide on the growth and biomass partitioning in corn (zea mays), itchgrass (Rottbiellia exalata concentrations of 350 ppM, 600 ppM, and 1000 ppM were considered. Dry matter production in soybean and velvetleaf was increased significantly by raising the CO2 concentration above 350 ppM. Dry matter production in itchgrass was greatest at 600 ppM; CO2 levels did not affect dry matter production in corn. Weed growth with each plant at the various CO2 concentrations was also measured. CO2 enrichment increased weed growth in weeds planted with soybeanmore » and velvetleaf; weeds planted with corn and itchgrass did not experience any significant increase in growth. (18 references, 4 tables)« less

The effects of first gestation and lactation on bone metabolism in dairy goats and milk sheep.

PubMed

Liesegang, A; Risteli, J; Wanner, M

2006-06-01

The goal of the present study was to compare mobilization rate of calcium (Ca) from bone in pregnant and lactating goats and sheep. Blood samples were collected from goats and sheep monthly during pregnancy and at 1, 2, and 4 weeks postpartum (pp) and monthly during lactation until 6 months after parturition. Total bone mineral content (BMC) and total bone mineral density (BMD) were quantified using peripheral quantitative computed tomography at the same intervals as the blood was taken. Bone resorption was assessed by immunoassays quantitating two epitopes of the carboxyterminal telopeptide of type I collagen (ICTP, CTX). Bone formation was estimated by quantifying serum osteocalcin (OC) and bone-specific alkaline phosphatase (bAP). In addition, Ca and 1,25-dihydroxy vitamin D (1,25-VITD) concentrations were determined in serum. Mean ICTP and CTX concentrations of both animal species increased the first week after parturition. By the second week pp, the concentrations of both markers had decreased toward early gestation levels. In contrast, mean OC concentrations continually decreased until the 1st week pp. By the 2nd week pp, the mean concentrations of OC started to increase again. Mean bAP activities decreased during gestation and reached a nadir in the first week pp in goats and 4 weeks pp in sheep. Afterwards, mean bAP activities increased again in goats and sheep. 1,25-VITD concentrations peaked the first week pp and returned to early gestation values thereafter. Total BMC and BMD decreased from the 4th month of pregnancy until the 1st week pp in both species. Afterwards, BMC increased throughout the first month pp in goats and the first 3 months pp in sheep. BMD levels of sheep and goats returned to prepartum levels during lactation. The resorptive phase of bone remodeling is accelerated at parturition and in early lactation and is uncoupled from the process of bone formation. This allows the animal to achieve Ca homeostasis at the expense of bone. Increased bone remodeling during lactation may represent physiological mechanisms to help replace the maternal skeleton lost as the animal adapted to enormously increased Ca losses to the fetus and milk in late gestation and early lactation.

Changes in body composition in apparently healthy urban Indian women up to 3 years postpartum.

PubMed

Kajale, Neha A; Khadilkar, Anuradha V; Chiplonkar, Shashi A; Khadilkar, Vaman

2015-01-01

Dietary and life style practices differ in postpartum (PP) and nonpregnant Indian women. Effect of these practices on postpartum weight retention (PPWR) and development of cardio-metabolic risk (CMR) has been scarcely studied in urban women. Aims of this study were to (i) compare anthropometry, biochemical parameters and body composition up to 3 years PP (ii) effect of PPWR, dietary fat intake and physical activity on CMR factors. Cross-sectional, 300-fullterm, apparently healthy primi-parous women (28.6 ± 3.4 years) randomly selected. 128 women within 7-day of delivery (Group-A), 88 with 1-2 years (Group-B) and 84 with 3-4-year-old-children (Group-C) were studied. Anthropometry, sociodemographic status, physical activity, diet, clinical examination, biochemical tests, body composition, at total body (TB), by dual energy X-ray absorptiometry (GE-Lunar DPX) were collected. Women at 3-year PP showed higher weight retention (6.5[10] kg) than at 1-year (3.0[7] kg) (median [IQR]). Android fat % (central obesity) increased (P < 0.05) at 1-year PP (47 ± 10.0%) when compared to 1-week PP (44.3 ± 6.7%) and remained elevated at 3-year PP (45.6 ± 10.2%). Regression analysis revealed that at 1-year PP, increase in PPWR (Odd Ratio [OR] 1.8, 95% confidence interval [CI] = [1.2, 2.5], P < 0.001) and inactivity (OR 1.4, 95% CI= (0.97, 2.0), P < 0.1) were predictors for CMR. At 3-year PP, only PPWR was responsible for increase in CMR parameters (OR 1.6, 95% CI = (1.3, 2.3), P < 0.001) and not inactivity (P > 0.1). Postdelivery, low physical activity and higher PPWR may increase CMR in Indian women.

Transfusion of Plasma Collected at Late Phase after Preconditioning Reduces Myocardial Infarct Size Induced by Ischemia-reperfusion in Rats In vivo.

PubMed

Zhao, Yang; Zheng, Zhi-Nan; Cheung, Chi-Wai; Zuo, Zhi-Yi; Jin, San-Qing

2017-02-05

Plasma transfusion is a common clinical practice. Remote ischemic preconditioning (RIPC) protects organs against ischemia-reperfusion (IR) injury. Whether preconditioned plasma (PP), collected at late phase after RIPC, could protect organs against IR injury in vivo is unknown. This study explored whether transfusion of PP could reduce myocardial infarct size (IS) after IR in rat in vivo. Eighty Lewis rats were randomized to eight groups (n = 10 for each group). Two groups of plasma donor rats donated plasma at 48 h after transient limb ischemia (PP) or control protocol (nonpreconditioned plasma [NPP]). Six groups of recipient rats received normal saline (NS; NS-IR 1, and NS-IR 24 groups), NPP (NPP-IR 1 and NPP-IR 24 groups), or PP (PP-IR 1 and PP-IR 24 groups) at one or 24 h before myocardial IR. Myocardial IR consisted of 30-min left anterior descending (LAD) coronary artery occlusion and 180-min reperfusion. The area at risk (AAR) and infarct area were determined by double-staining with Evans blue and triphenyltetrazolium chloride. IS was calculated by infarct area divided by AAR. This was a 3 × 2 factorial design study, and factorial analysis was used to evaluate the data. If an interaction between the fluid and transfusion time existed, one-way analysis of variance with Bonferroni correction for multiple comparisons was used to analyze the single effects of fluid type when the transfusion time was fixed. IS in the NPP-IR 1 and PP-IR 1 groups was smaller than in the NS-IR 1 group (F = 6.838, P = 0.005; NPP-IR 1: 57 ± 8% vs. NS-IR1: 68 ± 6%, t = 2.843, P = 0.020; PP-IR 1: 56 ± 8% vs. NS-IR 1: 68 ± 6%, t = 3.102, P = 0.009), but no significant difference was detected between the NPP-IR 1 and PP-IR 1 groups (57 ± 8% vs. 56 ± 8%, t = 0.069, P = 1.000). IS in the NPP-IR 24 and PP-IR 24 groups was smaller than in the NS-IR 24 group (F = 24.796, P< 0.001; NPP-IR 24: 56% ± 7% vs. NS-IR 24: 68 ± 7%, t = 3.102, P = 0.026; PP-IR 24: 40 ± 9% vs. NS-IR 24: 68 ± 7%, t = 7.237, P< 0.001); IS in the PP-IR 24 group was smaller than in the NPP-IR 24 group (40 ± 9% vs. 56 ± 7%, t = 4.135, P = 0.002). Transfusion of PP collected at late phase after remote ischemic preconditioning could reduce IS, suggesting that late-phase cardioprotection was transferable in vivo.

Selective ablation of Ppp1cc gene in testicular germ cells causes oligo-teratozoospermia and infertility in mice.

PubMed

Sinha, Nilam; Puri, Pawan; Nairn, Angus C; Vijayaraghavan, Srinivasan

2013-11-01

The four isoforms of serine/threonine phosphoprotein phosphatase 1 (PP1), derived from three genes, are among the most conserved proteins known. The Ppp1cc gene encodes two alternatively spliced variants, PP1 gamma1 (PPP1CC1) and PP1 gamma2 (PPP1CC2). Global deletion of the Ppp1cc gene, which causes loss of both isoforms, results in male infertility due to impaired spermatogenesis. This phenotype was assumed to be due to the loss of PPP1CC2, which is abundant in testis. While PPP1CC2 is predominant, other PP1 isoforms are also expressed in testis. Given the significant homology between the four PP1 isoforms, the lack of compensation by the other PP1 isoforms for loss of one, only in testis, is surprising. Here we document, for the first time, expression patterns of the PP1 isoforms in postnatal developing and adult mouse testis. The timing and sites of testis expression of PPP1CC1 and PPP1CC2 in testis are nonoverlapping. PPP1CC2 is the only one of the four PP1 isoforms not detected in sertoli cells and spermatogonia. Conversely, PPP1CC2 may be the only PP1 isoform expressed in postmeiotic germ cells. Deletion of the Ppp1cc gene in germ cells at the differentiated spermatogonia stage of development and beyond in Stra8 promoter-driven Cre transgenic mice results in oligo-terato-asthenozoospermia and male infertility, thus phenocopying global Ppp1cc null (-/-) mice. Taken together, these results confirm that spermatogenic defects observed in the global Ppp1cc knockout mice and in mice expressing low levels of PPP1CC2 in testis are due to compromised functions of PPP1CC2 in meiotic and postmeiotic germ cells.

Control in the Rate-Determining Step Provides a Promising Strategy To Develop New Catalysts for CO2 Hydrogenation: A Local Pair Natural Orbital Coupled Cluster Theory Study.

PubMed

Mondal, Bhaskar; Neese, Frank; Ye, Shengfa

2015-08-03

The development of efficient catalysts with base metals for CO2 hydrogenation has always been a major thrust of interest. A series of experimental and theoretical work has revealed that the catalytic cycle typically involves two key steps, namely, base-promoted heterolytic H2 splitting and hydride transfer to CO2, either of which can be the rate-determining step (RDS) of the entire reaction. To explore the determining factor for the nature of RDS, we present herein a comparative mechanistic investigation on CO2 hydrogenation mediated by [M(H)(η(2)-H2)(PP3(Ph))](n+) (M = Fe(II), Ru(II), and Co(III); PP3(Ph) = tris(2-(diphenylphosphino)phenyl)phosphine) type complexes. In order to construct reliable free energy profiles, we used highly correlated wave function based ab initio methods of the coupled cluster type alongside the standard density functional theory. Our calculations demonstrate that the hydricity of the metal-hydride intermediate generated by H2 splitting dictates the nature of the RDS for the Fe(II) and Co(III) systems, while the RDS for the Ru(II) catalyst appears to be ambiguous. CO2 hydrogenation catalyzed by the Fe(II) complex that possesses moderate hydricity traverses an H2-splitting RDS, whereas the RDS for the high-hydricity Co(III) species is found to be the hydride transfer. Thus, our findings suggest that hydricity can be used as a practical guide in future catalyst design. Enhancing the electron-accepting ability of low-hydricity catalysts is likely to improve their catalytic performance, while increasing the electron-donating ability of high-hydricity complexes may speed up CO2 conversion. Moreover, we also established the active roles of base NEt3 in directing the heterolytic H2 splitting and assisting product release through the formation of an acid-base complex.

Liver carbohydrates metabolism: A new islet-neogenesis associated protein peptide (INGAP-PP) target.

PubMed

Villagarcía, Hernán Gonzalo; Román, Carolina Lisi; Castro, María Cecilia; González, Luisa Arbeláez; Ronco, María Teresa; Francés, Daniel Eleazar; Massa, María Laura; Maiztegui, Bárbara; Flores, Luis Emilio; Gagliardino, Juan José; Francini, Flavio

2018-03-01

Islet-Neogenesis Associated Protein-Pentadecapeptide (INGAP-PP) increases β-cell mass and enhances glucose and amino acids-induced insulin secretion. Our aim was to demonstrate its effect on liver metabolism. For that purpose, adult male Wistar rats were injected twice-daily (10 days) with saline solution or INGAP-PP (250 μg). Thereafter, serum glucose, triglyceride and insulin levels were measured and homeostasis model assessment (HOMA-IR) and hepatic insulin sensitivity (HIS) were determined. Liver glucokinase and glucose-6-phosphatase (G-6-Pase) expression and activity, phosphoenolpyruvate carboxykinase (PEPCK) expression, phosphofructokinase-2 (PFK-2) protein content, P-Akt/Akt and glycogen synthase kinase-3β (P-GSK3/GSK3) protein ratios and glycogen deposit were also determined. Additionally, glucokinase activity and G-6-Pase and PEPCK gene expression were also determined in isolated hepatocytes from normal rats incubated with INGAP-PP (5 μg/ml). INGAP-PP administration did not modify any of the serum parameters tested but significantly increased activity of liver glucokinase and the protein level of its cytosolic activator, PFK-2. Conversely, INGAP-PP treated rats decreased gene expression and enzyme activity of gluconeogenic enzymes, G-6-Pase and PEPCK. They also showed a higher glycogen deposit and P-GSK3/GSK3 and P-Akt/Akt ratio. In isolated hepatocytes, INGAP-PP increased GK activity and decreased G-6-Pase and PEPCK expression. These results demonstrate a direct effect of INGAP-PP on the liver acting through P-Akt signaling pathway. INGAP-PP enhances liver glucose metabolism and deposit and reduces its production/output, thereby contributing to maintain normal glucose homeostasis. These results reinforce the concept that INGAP-PP might become a useful tool to treat people with impaired islet/liver glucose metabolism as it occurs in T2D. Copyright © 2018 Elsevier Inc. All rights reserved.

Military Professionalism and Political Influence: A Case Study of the Mexican Military, 1917-1940

DTIC Science & Technology

1992-01-01

producto nacional," in Mexico , 50 afios de revoluci6n: La economia , pp. 578, and 588-589. 2 2 Ibid., pp. 588-589. 2 3 james W. Wilkie, The Mexican...by M.R. Van Gils. Belgium: Rotterdam University Press, 1971, pp. 247-265. M~xico, 50 ahos de revoluci6n: La economia . Mexico , D.F.: Fondo de Cultura...government. Thus, Mexico is an ix extremely intpresting case to examine, not only because it is one of ½.ie few nations in Latin America that has enjoyed a

X-linked microtubule-associated protein, Mid1, regulates axon development

PubMed Central

Lu, Tingjia; Chen, Renchao; Cox, Timothy C.; Moldrich, Randal X.; Kurniawan, Nyoman; Tan, Guohe; Perry, Jo K.; Ashworth, Alan; Bartlett, Perry F.; Xu, Li; Zhang, Jing; Lu, Bin; Wu, Mingyue; Shen, Qi; Liu, Yuanyuan; Richards, Linda J.; Xiong, Zhiqi

2013-01-01

Opitz syndrome (OS) is a genetic neurological disorder. The gene responsible for the X-linked form of OS, Midline-1 (MID1), encodes an E3 ubiquitin ligase that regulates the degradation of the catalytic subunit of protein phosphatase 2A (PP2Ac). However, how Mid1 functions during neural development is largely unknown. In this study, we provide data from in vitro and in vivo experiments suggesting that silencing Mid1 in developing neurons promotes axon growth and branch formation, resulting in a disruption of callosal axon projections in the contralateral cortex. In addition, a similar phenotype of axonal development was observed in the Mid1 knockout mouse. This defect was largely due to the accumulation of PP2Ac in Mid1-depleted cells as further down-regulation of PP2Ac rescued the axonal phenotype. Together, these data demonstrate that Mid1-dependent PP2Ac turnover is important for normal axonal development and that dysregulation of this process may contribute to the underlying cause of OS. PMID:24194544

X-linked microtubule-associated protein, Mid1, regulates axon development.

PubMed

Lu, Tingjia; Chen, Renchao; Cox, Timothy C; Moldrich, Randal X; Kurniawan, Nyoman; Tan, Guohe; Perry, Jo K; Ashworth, Alan; Bartlett, Perry F; Xu, Li; Zhang, Jing; Lu, Bin; Wu, Mingyue; Shen, Qi; Liu, Yuanyuan; Richards, Linda J; Xiong, Zhiqi

2013-11-19

Opitz syndrome (OS) is a genetic neurological disorder. The gene responsible for the X-linked form of OS, Midline-1 (MID1), encodes an E3 ubiquitin ligase that regulates the degradation of the catalytic subunit of protein phosphatase 2A (PP2Ac). However, how Mid1 functions during neural development is largely unknown. In this study, we provide data from in vitro and in vivo experiments suggesting that silencing Mid1 in developing neurons promotes axon growth and branch formation, resulting in a disruption of callosal axon projections in the contralateral cortex. In addition, a similar phenotype of axonal development was observed in the Mid1 knockout mouse. This defect was largely due to the accumulation of PP2Ac in Mid1-depleted cells as further down-regulation of PP2Ac rescued the axonal phenotype. Together, these data demonstrate that Mid1-dependent PP2Ac turnover is important for normal axonal development and that dysregulation of this process may contribute to the underlying cause of OS.

Risk factors that affect reproductive target achievement in fertile dairy cows.

PubMed

Aungier, S P M; Roche, J F; Diskin, M G; Crowe, M A

2014-01-01

The aims of the present study were to investigate (1) the risk factors that influence the achievement of reproductive targets postpartum (pp) and (2) the key factors that influence pregnancy rate following first artificial insemination (AI) in dairy cows. Ninety-eight Holstein-Friesian pp cows were blood sampled from wk 1 to 4 pp for hematology and biochemistry. Reproductive tract health was assessed weekly by ultrasonography and vaginal mucus scoring. Body condition score (BCS), lameness score, and milk yield were assessed every 2 wk. Milk samples for progesterone assay were collected twice weekly and on d 4, 5, and 7 after AI. Risk factors associated with achieving reproductive targets depended on (1) increased metabolic activity of the liver (increased glutamate dehydrogenase at calving and increased γ-glutamyl transpeptidase in wk 4), (2) a competent immune system (increased neutrophils in wk 1; decreased α1-acid glycoprotein in wk 1, 2, and 3), (3) an endocrine system that was capable of responding by producing sufficient triiodothyronine in wk 2 and increased insulin-like growth factor I in wk 3 and 4, (4) a lower negative energy balance status (decreased nonesterified fatty acid concentration in wk 1; decreased β-hydroxybutyrate concentration in wk 2; BCS loss between calving and d 28 pp <0.5), (5) good reproductive tract health [normal uterine scan at d 45 pp; clear vaginal mucus discharge at first ovulation and at d 45 pp; resumed ovarian cyclicity by the end of the voluntary waiting period (≥ d 35 pp)], and (6) adequate diet (to ensure increased glutathione peroxidase in wk 2 and 3 and increased magnesium in wk 4). Risk factors that increased the odds of a successful first AI were previous ovulation(s) (odds ratio=3.17 per ovulation), BCS >2.5 at AI (odds ratio=3.01), and clear vaginal mucus (score=0) compared with purulent mucus (score >0) 4 d after first AI (odds ratio=2.99). In conclusion, this study identified key risk factors in the early pp period that give a higher probability of cows achieving their reproductive targets and of having a first-AI pregnancy. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Accuracy of enhanced and unenhanced MRI in diagnosing scaphoid proximal pole avascular necrosis and predicting surgical outcome.

PubMed

Fox, M G; Wang, D T; Chhabra, A B

2015-11-01

Determine the sensitivity, specificity and accuracy of unenhanced and enhanced MRI in diagnosing scaphoid proximal pole (PP) avascular necrosis (AVN) and correlate whether MRI can help guide the selection of a vascularized or nonvascularized bone graft. The study was approved by the IRB. Two MSK radiologists independently performed a retrospective review of unenhanced and enhanced MRIs from 18 patients (16 males, 2 females; median age, 17.5 years) with scaphoid nonunions and surgery performed within 65 days of the MRI. AVN was diagnosed on the unenhanced MRI when a diffusely decreased T1-W signal was present in the PP and on the enhanced MRI when PP enhancement was less than distal pole enhancement. Surgical absence of PP bleeding was diagnostic of PP AVN. Postoperative osseous union (OU) was assessed with computed tomography and/or radiographs. Sensitivity, specificity and accuracy for PP AVN were 71, 82 and 78% for unenhanced and 43, 82 and 67% for enhanced MRI. Patients with PP AVN on unenhanced MRI had 86% (6/7) OU; 100% (5/5) OU with vascularized bone grafts and 50% (1/2) OU with nonvascularized grafts. Patients with PP AVN on enhanced MRI had 80% (4/5) OU; 100% (3/3) OU with vascularized bone grafts and 50% (1/2) OU with nonvascularized grafts. Patients with viable PP on unenhanced and enhanced MRI had 91% (10/11) and 92% (12/13) OU, respectively, all but one with nonvascularized graft. When PP AVN is evident on MRI, OU is best achieved with vascularized grafts. If PP AVN is absent, OU is successful with nonvascularized grafts.

Mn(II) Oxidation by the Multicopper Oxidase Complex Mnx: A Coordinated Two-Stage Mn(II)/(III) and Mn(III)/(IV) Mechanism.

PubMed

Soldatova, Alexandra V; Romano, Christine A; Tao, Lizhi; Stich, Troy A; Casey, William H; Britt, R David; Tebo, Bradley M; Spiro, Thomas G

2017-08-23

The bacterial manganese oxidase MnxG of the Mnx protein complex is unique among multicopper oxidases (MCOs) in carrying out a two-electron metal oxidation, converting Mn(II) to MnO 2 nanoparticles. The reaction occurs in two stages: Mn(II) → Mn(III) and Mn(III) → MnO 2 . In a companion study , we show that the electron transfer from Mn(II) to the low-potential type 1 Cu of MnxG requires an activation step, likely forming a hydroxide bridge at a dinuclear Mn(II) site. Here we study the second oxidation step, using pyrophosphate (PP) as a Mn(III) trap. PP chelates Mn(III) produced by the enzyme and subsequently allows it to become a substrate for the second stage of the reaction. EPR spectroscopy confirms the presence of Mn(III) bound to the enzyme. The Mn(III) oxidation step does not involve direct electron transfer to the enzyme from Mn(III), which is shown by kinetic measurements to be excluded from the Mn(II) binding site. Instead, Mn(III) is proposed to disproportionate at an adjacent polynuclear site, thereby allowing indirect oxidation to Mn(IV) and recycling of Mn(II). PP plays a multifaceted role, slowing the reaction by complexing both Mn(II) and Mn(III) in solution, and also inhibiting catalysis, likely through binding at or near the active site. An overall mechanism for Mnx-catalyzed MnO 2 production from Mn(II) is presented.

A Clinically Relevant Variant of the Human Hydrogen Sulfide-Synthesizing Enzyme Cystathionine β-Synthase: Increased CO Reactivity as a Novel Molecular Mechanism of Pathogenicity?

PubMed Central

Malagrinò, Francesca; Santo, Paulo E.; Gutierres, André; Bandeiras, Tiago M.; Leandro, Paula

2017-01-01

The human disease classical homocystinuria results from mutations in the gene encoding the pyridoxal 5′-phosphate- (PLP-) dependent cystathionine β-synthase (CBS), a key enzyme in the transsulfuration pathway that controls homocysteine levels, and is a major source of the signaling molecule hydrogen sulfide (H2S). CBS activity, contributing to cellular redox homeostasis, is positively regulated by S-adenosyl-L-methionine (AdoMet) but fully inhibited upon CO or NO• binding to a noncatalytic heme moiety. Despite extensive studies, the molecular basis of several pathogenic CBS mutations is not yet fully understood. Here we found that the ferrous heme of the reportedly mild p.P49L CBS variant has altered spectral properties and markedly increased affinity for CO, making the protein much more prone than wild type (WT) CBS to inactivation at physiological CO levels. The higher CO affinity could result from the slightly higher flexibility in the heme surroundings revealed by solving at 2.80-Å resolution the crystallographic structure of a truncated p.P49L. Additionally, we report that p.P49L displays impaired H2S-generating activity, fully rescued by PLP supplementation along the purification, despite a minor responsiveness to AdoMet. Altogether, the results highlight how increased propensity to CO inactivation of an otherwise WT-like variant may represent a novel pathogenic mechanism in classical homocystinuria. PMID:28421128

Mitochondria-targeted catalase reduces abnormal APP processing, amyloid β production and BACE1 in a mouse model of Alzheimer's disease: implications for neuroprotection and lifespan extension.

PubMed

Mao, Peizhong; Manczak, Maria; Calkins, Marcus J; Truong, Quang; Reddy, Tejaswini P; Reddy, Arubala P; Shirendeb, Ulziibat; Lo, Herng-Hsiang; Rabinovitch, Peter S; Reddy, P Hemachandra

2012-07-01

The purpose of this study was to investigate the protective effects of the mitochondria-targeted antioxidant catalase (MCAT) and lifespan extension in mice that express amyloid beta (Aβ). Using immunoblotting and immunostaining analyses, we measured the production of full-length amyloid precursor protein (APP), soluble APPα, C-terminal fragments CTF99 and CTF83, monomeric and oligomeric Aβ, Aβ deposits and beta site amyloid precursor protein cleaving enzyme 1 (BACE1), in different stages of disease progression in MCAT/AβPP and AβPP mice. Using quantitative reverse transcriptase polymerase chain reaction and immunostaining analyses, we studied the expression of catalase, BACE1, the Alzheimer's disease (AD) markers, synaptophysin, APP, neprilysin, insulin-degrading enzyme and transthyretin in MCAT, AβPP, MCAT/AβPP and wild-type (WT) mice. Using the high pressure liquid chromatography analysis of 8-hydroxy-2-deoxyguanosine, we measured oxidative DNA damage in the cerebral cortical tissues from MCAT, AβPP, MCAT/AβPP and WT mice. We found that the AβPP transgenic mice that carried the human MCAT gene lived 5 months longer than did the AβPP mice. We also found that the overexpression of MCAT in the brain sections from the MCAT/AβPP transgenic mice significantly correlated with a reduction in the levels of full-length APP, CTF99, BACE1, Aβ levels (40 and 42), Aβ deposits and oxidative DNA damage relative to the brain sections from the AβPP mice. Interestingly, we found significantly increased levels of soluble APPα and CTF83 in the MCAT/AβPP mice, relative to the AβPP mice. These data provide direct evidence that oxidative stress plays a primary role in AD etiopathology and that in MCAT mice express Aβ, MCAT prevents abnormal APP processing, reduces Aβ levels and enhances Aβ-degrading enzymes in mice at different ages, corresponding to different stages of disease progression. These findings indicate that mitochondria-targeted molecules may be an effective therapeutic approach to treat patients with AD.

Mitochondria-targeted catalase reduces abnormal APP processing, amyloid β production and BACE1 in a mouse model of Alzheimer's disease: implications for neuroprotection and lifespan extension

PubMed Central

Mao, Peizhong; Manczak, Maria; Calkins, Marcus J.; Truong, Quang; Reddy, Tejaswini P.; Reddy, Arubala P.; Shirendeb, Ulziibat; Lo, Herng-Hsiang; Rabinovitch, Peter S.; Reddy, P. Hemachandra

2012-01-01

The purpose of this study was to investigate the protective effects of the mitochondria-targeted antioxidant catalase (MCAT) and lifespan extension in mice that express amyloid beta (Aβ). Using immunoblotting and immunostaining analyses, we measured the production of full-length amyloid precursor protein (APP), soluble APPα, C-terminal fragments CTF99 and CTF83, monomeric and oligomeric Aβ, Aβ deposits and beta site amyloid precursor protein cleaving enzyme 1 (BACE1), in different stages of disease progression in MCAT/AβPP and AβPP mice. Using quantitative reverse transcriptase polymerase chain reaction and immunostaining analyses, we studied the expression of catalase, BACE1, the Alzheimer's disease (AD) markers, synaptophysin, APP, neprilysin, insulin-degrading enzyme and transthyretin in MCAT, AβPP, MCAT/AβPP and wild-type (WT) mice. Using the high pressure liquid chromatography analysis of 8-hydroxy-2-deoxyguanosine, we measured oxidative DNA damage in the cerebral cortical tissues from MCAT, AβPP, MCAT/AβPP and WT mice. We found that the AβPP transgenic mice that carried the human MCAT gene lived 5 months longer than did the AβPP mice. We also found that the overexpression of MCAT in the brain sections from the MCAT/AβPP transgenic mice significantly correlated with a reduction in the levels of full-length APP, CTF99, BACE1, Aβ levels (40 and 42), Aβ deposits and oxidative DNA damage relative to the brain sections from the AβPP mice. Interestingly, we found significantly increased levels of soluble APPα and CTF83 in the MCAT/AβPP mice, relative to the AβPP mice. These data provide direct evidence that oxidative stress plays a primary role in AD etiopathology and that in MCAT mice express Aβ, MCAT prevents abnormal APP processing, reduces Aβ levels and enhances Aβ-degrading enzymes in mice at different ages, corresponding to different stages of disease progression. These findings indicate that mitochondria-targeted molecules may be an effective therapeutic approach to treat patients with AD. PMID:22492996

Lysyl oxidase propeptide inhibits smooth muscle cell signaling and proliferation

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

Hurtado, Paola A.; Vora, Siddharth; Sume, Siddika Selva

2008-02-01

Lysyl oxidase is required for the normal biosynthesis and maturation of collagen and elastin. It is expressed by vascular smooth muscle cells, and its increased expression has been previously found in atherosclerosis and in models of balloon angioplasty. The lysyl oxidase propeptide (LOX-PP) has more recently been found to have biological activity as a tumor suppressor, and it inhibits Erk1/2 Map kinase activation. We reasoned that LOX-PP may have functions in normal non-transformed cells. We, therefore, investigated its effects on smooth muscle cells, focusing on important biological processes mediated by Erk1/2-dependent signaling pathways including proliferation and matrix metalloproteinase-9 (MMP-9) expression.more » In addition, we investigated whether evidence for accumulation of LOX-PP could be found in vivo in a femoral artery injury model. Recombinant LOX-PP was expressed and purified, and was found to inhibit primary rat aorta smooth muscle cell proliferation and DNA synthesis by more than 50%. TNF-{alpha}-stimulated MMP-9 expression and Erk1/2 activation were both significantly inhibited by LOX-PP. Immunohistochemistry studies carried out with affinity purified anti-LOX-PP antibody showed that LOX-PP epitopes were expressed at elevated levels in vascular lesions of injured arteries. These novel data suggest that LOX-PP may provide a feedback control mechanism that serves to inhibit properties associated with the development of vascular pathology.« less

Physical Performance and Physical Activity in Older Adults: Associated but Separate Domains of Physical Function in Old Age

PubMed Central

van Lummel, Rob C.; Walgaard, Stefan; Pijnappels, Mirjam; Elders, Petra J. M.; Garcia-Aymerich, Judith; van Dieën, Jaap H.; Beek, Peter J.

2015-01-01

Background Physical function is a crucial factor in the prevention and treatment of health conditions in older adults and is usually measured objectively with physical performance tests and/or physical activity monitoring. Objective To examine whether 1) physical performance (PP) and physical activity (PA) constitute separate domains of physical function; 2) differentiation of PA classes is more informative than overall PA. Design Cross-sectional study to explore the relationships within and among PP and PA measures. Methods In 49 older participants (83±7 years; M±SD), performance-based tests were conducted and PA was measured for one week. Activity monitor data were reduced in terms of duration, periods, and mean duration of periods of lying, sitting, standing and locomotion. The relation between and within PP scores and PA outcomes were analysed using rank order correlation and factor analysis. Results Factor structure after varimax rotation revealed two orthogonal factors explaining 78% of the variance in the data: one comprising all PA variables and one comprising all PP variables. PP scores correlated moderately with PA in daily life. Differentiation of activity types and quantification of their duration, intensity and frequency of occurrence provided stronger associations with PP, as compared to a single measure of acceleration expressing overall PA. Limitations For independent validation, the conclusions about the validity of the presented conceptual framework and its clinical implications need to be confirmed in other studies. Conclusions PP and PA represent associated but separate domains of physical function, suggesting that an improvement of PP does not automatically imply an increase of PA, i.e. a change to a more active lifestyle. Differentiation of activity classes in the analysis of PA provides more insights into PA and its association with PP than using a single overall measure of acceleration. PMID:26630268

Recognition of p63 by the E3 ligase ITCH: Effect of an ectodermal dysplasia mutant.

PubMed

Bellomaria, A; Barbato, Gaetano; Melino, G; Paci, M; Melino, Sonia

2010-09-15

The E3 ubiquitin ligase Itch mediates the degradation of the p63 protein. Itch contains four WW domains which are pivotal for the substrate recognition process. Indeed, this domain is implicated in several signalling complexes crucially involved in human diseases including Muscular Dystrophy, Alzheimer's Disease and Huntington Disease. WW domains are highly compact protein-protein binding modules that interact with short proline-rich sequences. The four WW domains present in Itch belong to the Group I type, which binds polypeptides with a PY motif characterized by a PP xY consensus sequence, where x can be any residue. Accordingly, the Itch-p63 interaction results from a direct binding of Itch-WW2 domain with the PY motif of p63. Here, we report a structural analysis of the Itch-p63 interaction by fluorescence, CD and NMR spectroscopy. Indeed, we studied the in vitro interaction between Itch-WW2 domain and p63(534-551), an 18-mer peptide encompassing a fragment of the p63 protein including the PY motif. In addition, we evaluated the conformation and the interaction with Itch-WW2 of a site specific mutant of p63, I549T, that has been reported in both Hay-Wells syndrome and Rapp-Hodgkin syndrome. Based on our results, we propose an extended PP xY motif for the Itch recognition motif (P-P-P-Y-x(4)-[ST]-[ILV]), which includes these C-terminal residues to the PP xY motif.

Surface treatment of polypropylene (PP) film by 50 Hz dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure

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

Joshi, Ujjwal Man, E-mail: umjoshi@gmail.com; Subedi, Deepak Prasad, E-mail: deepaksubedi2001@yahoo.com

Thin films of polypropylene (PP) are treated for improving hydrophilicity using non-thermal plasma generated by 50 Hz line frequency dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure. PP samples before and after the treatments are studied using contact angle measurements, surface free energy calculations and scanning electron microscopy (SEM). Distilled water (H{sub 2}O), glycerol (C{sub 3}H{sub 8}O{sub 3}) and diiodomethane (CH{sub 2}I{sub 2}) are used as test liquids. The contact angle measurements between test liquids and PP samples are used to determine total surface free energy using sessile drop technique. PP films show a remarkable increase inmore » surface free energy after plasma treatment. SEM analysis of the plasma-treated PP films shows that plasma treatment introduces greater roughness on the surface leading to the increased surface free energy. Furthermore, it is found that introducing a small quantity of argon can enhance the surface treatment remarkably.« less

A prospective international observational prevalence study on prone positioning of ARDS patients: the APRONET (ARDS Prone Position Network) study.

PubMed

Guérin, C; Beuret, P; Constantin, J M; Bellani, G; Garcia-Olivares, P; Roca, O; Meertens, J H; Maia, P Azevedo; Becher, T; Peterson, J; Larsson, A; Gurjar, M; Hajjej, Z; Kovari, F; Assiri, A H; Mainas, E; Hasan, M S; Morocho-Tutillo, D R; Baboi, L; Chrétien, J M; François, G; Ayzac, L; Chen, L; Brochard, L; Mercat, A

2018-01-01

While prone positioning (PP) has been shown to improve patient survival in moderate to severe acute respiratory distress syndrome (ARDS) patients, the rate of application of PP in clinical practice still appears low. This study aimed to determine the prevalence of use of PP in ARDS patients (primary endpoint), the physiological effects of PP, and the reasons for not using it (secondary endpoints). The APRONET study was a prospective international 1-day prevalence study performed four times in April, July, and October 2016 and January 2017. On each study day, investigators in each ICU had to screen every patient. For patients with ARDS, use of PP, gas exchange, ventilator settings and plateau pressure (Pplat) were recorded before and at the end of the PP session. Complications of PP and reasons for not using PP were also documented. Values are presented as median (1st-3rd quartiles). Over the study period, 6723 patients were screened in 141 ICUs from 20 countries (77% of the ICUs were European), of whom 735 had ARDS and were analyzed. Overall 101 ARDS patients had at least one session of PP (13.7%), with no differences among the 4 study days. The rate of PP use was 5.9% (11/187), 10.3% (41/399) and 32.9% (49/149) in mild, moderate and severe ARDS, respectively (P = 0.0001). The duration of the first PP session was 18 (16-23) hours. Measured with the patient in the supine position before and at the end of the first PP session, PaO 2 /F I O 2 increased from 101 (76-136) to 171 (118-220) mmHg (P = 0.0001) driving pressure decreased from 14 [11-17] to 13 [10-16] cmH 2 O (P = 0.001), and Pplat decreased from 26 [23-29] to 25 [23-28] cmH 2 O (P = 0.04). The most prevalent reason for not using PP (64.3%) was that hypoxemia was not considered sufficiently severe. Complications were reported in 12 patients (11.9%) in whom PP was used (pressure sores in five, hypoxemia in two, endotracheal tube-related in two ocular in two, and a transient increase in intracranial pressure in one). In conclusion, this prospective international prevalence study found that PP was used in 32.9% of patients with severe ARDS, and was associated with low complication rates, significant increase in oxygenation and a significant decrease in driving pressure.

Protein Phosphatase 2A Signaling in Human Prostate Cancer

DTIC Science & Technology

2011-06-01

centrifugation, 25 mL of supernatant was transferred to an assay plate; 100 mL of Malachite Green phosphate detection solution was added and incu...prostate cancer cells was resolved and immunoblotted for PP2AC and b-actin (internal control). PP2A activity was determined by malachite green–based

The RDF and Amphibious Warfare.

DTIC Science & Technology

1982-03-01

Retrieval oy Manfred Kocnen," 10 pp., Mcr 78 lPuolisnea 3s a Letter to the Editor, Journal of Documentation, vol. 31 , PP 226 No. 4, pages 298-301...ctlon rants,w 25 pp., 3cr 1979, ’C 4061 529 𔃿 ’~~~~~~-s’. Roa~ ., n a .e~nn mlzrani, marce i~., "The 38,i:,asslcaI -- efs70 71 . Soverai 5xiIeCTlI...a Vtaas," 71 Do-. an 1981, A2 V96.)5q 0nln 1. OIme0 2 -P 300 pp 313 Jondow. James and Schmildt. Peter, * wOn tha Estimation of Roberts, Stephen S

Saturated fat supplementation interacts with dietary forage neutral detergent fiber content during the immediate postpartum and carryover periods in Holstein cows: Production responses and digestibility of nutrients.

PubMed

Piantoni, P; Lock, A L; Allen, M S

2015-05-01

Forty-eight multiparous cows were used in a randomized complete block design experiment with a 2×2 factorial arrangement of treatments to determine the interaction between a highly saturated free FA supplement (SFFA) and dietary forage neutral detergent fiber (fNDF) content on production responses and nutrient digestibility of dairy cows in the postpartum period. Treatment diets were offered from 1 to 29d postpartum (postpartum period; PP) and contained 20 or 26% fNDF (50:50 corn silage:alfalfa silage and hay, dry matter basis) and 0 or 2% SFFA [Energy Booster 100 (Milk Specialties Global, Eden Prairie, MN); 96.1% FA: 46.2% C18:0 and 37.0% C16:0]. From 30 to 71d postpartum (carryover period), a common diet (~23% fNDF, 0% SFFA) was offered to all cows to evaluate carryover effects of the treatment diets early in lactation. During the PP, higher fNDF decreased dry matter intake (DMI) by 2.0 kg/d, whereas SFFA supplementation increased it by 1.4kg/d. In addition, high fNDF with 0% SFFA decreased DMI compared with the other diets and this difference increased throughout the PP. Treatments did not affect 3.5% fat-corrected milk yield during the PP but did during the carryover period when SFFA supplementation decreased 3.5% fat-corrected milk yield for the low-fNDF diet (51.1 vs. 58.7kg/d), but not for the high-fNDF diet (58.5 vs. 58.0kg/d). During the PP, lower fNDF and SFFA supplementation decreased body condition score loss. A tendency for an interaction between fNDF and SFFA indicated that low fNDF with 2% SFFA decreased body condition score loss compared with the other diets (-0.49 vs. -0.89). During the PP, lower fNDF and 2% SFFA supplementation decreased feed efficiency (3.5% fat-corrected milk/DMI) by 0.30 and 0.23 units, respectively. The low-fNDF diet with 2% SFFA decreased feed efficiency compared with other diets early in the PP, but this difference decreased over time. Supplementation of SFFA in the PP favored energy partitioning to body reserves and limited DMI depression for the high-fNDF diet, which might allow higher-fNDF diets to be fed to cows in the PP. However, SFFA supplemented in the low-fNDF diet during the PP affected production negatively in the carryover period. Dietary fNDF and SFFA interacted, affecting performance in the PP with carryover effects when cows were fed a common diet in early lactation. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Mussel farming impact on pelagic production and respiration rates in a coastal upwelling embayment (Ría de Vigo, NW Spain)

NASA Astrophysics Data System (ADS)

Froján, María; Castro, Carmen G.; Zúñiga, Diana; Arbones, Belén; Alonso-Pérez, Fernando; Figueiras, Francisco G.

2018-05-01

This paper provides the first diagnosis of the impact of mussel farming on the primary production (PP) and the metabolic balance in a coastal upwelling region (Ría de Vigo). Measurements of size-fractionated PP and microbial plankton metabolism were performed outside (reference station; ReS) and inside the farming area (raft station; RaS). At ReS, integrated PP was higher during upwelling (1.05 ± 0.45 g C m-2 d-1) with microphytoplankton dominating carbon fixation (74 ± 14%). The significance of nanophytoplankton and picophytoplankton increased during winter linked to lower PP (0.24 ± 0.03 g C m-2 d-1). Water column at ReS was always autotrophic with net community production (NCP) ranging from 186 ± 67 mmol O2 m-2 d-1 during upwelling to 43 ± 22 mmol O2 m-2 d-1 in winter. At RaS, there was a decrease in PP attributable not only to mussel consumption but also to the lower irradiance under mussel rafts. Concomitant decrease in NCP was also observed (by 56%), yet remained autotrophic, supporting the view that under current conditions food does not limit mussel growth in the Ría, thus securing the carrying capacity of the system in terms of production.

Fasting and meal-induced CCK and PP secretion following intragastric balloon treatment for obesity.

PubMed

Mathus-Vliegen, Elisabeth M H; de Groot, Gerrit H

2013-05-01

Satiety is centrally and peripherally mediated by gastrointestinal peptides and the vagal nerve. We aimed to investigate whether intragastric balloon treatment affects satiety through effects on fasting and meal-stimulated cholecystokinin (CCK) and pancreatic polypeptide (PP) secretion. Patients referred for obesity treatment were randomised to 13 weeks of sham treatment followed by 13 weeks of balloon treatment (group 1; sham/balloon) or to twice a 13-week period of balloon treatment (group 2; balloon/balloon). Blood samples were taken for fasting and meal-stimulated CCK and PP levels at the start (T0) and after 13 (T1) and 26 (T2) weeks. Patients filled out visual analogue scales (VAS) to assess satiety. Forty-two patients (35 females, body weight 125.1 kg, BMI 43.3 kg/m(2)) participated. In group 1, basal CCK levels decreased but meal-stimulated response remained unchanged after 13 weeks of sham treatment. In group 2, basal and meal-stimulated CCK levels decreased after 13 weeks of balloon treatment. At the end of the second 13-week period, when group 1 had their first balloon treatment, they duplicated the initial 13-week results of group 2, whereas group 2 continued their balloon treatment and reduced meal-stimulated CCK release. Both groups showed reduced meal-stimulated PP secretions at T1 and T2 compared to T0. Changes in diet composition and VAS scores were similar. Improvements in glucose homeostasis partly explained the PP results. The reduced CCK and PP secretion after balloon positioning was unexpected and may reflect delayed gastric emptying induced by the balloon. Improved glucose metabolism partly explained the reduced PP secretion. Satiety and weight loss were not adversely influenced by these hormonal changes.

Effect of blend ratio of PP/kapok blend nonwoven fabrics on oil sorption capacity.

PubMed

Lee, Young-Hee; Kim, Ji-Soo; Kim, Do-Hyung; Shin, Min-Seung; Jung, Young-Jin; Lee, Dong-Jin; Kim, Han-Do

2013-01-01

More research and development on novel oil sorbent materials is needed to protect the environmental pollution. New nonwoven fabrics (pads) of polypropylene (PP)/kapok blends (blend ratio: 100/0, 75/25, 50/50, 25/75 and 10/90) were prepared by needle punching process at a fixed (optimized) condition (punch density: 50 punches/cm2 and depth: 4mm). This study focused on the effect of blend ratio of PP/kapok nonwoven fabrics on oil sorption capacities to find the best blend ratio having the highest synergy effect. The PP/kapok blend (50/50) sample has the lowest bulk density and showed the best oil absorption capacity. The oil sorption capacity of PP/kapok blend (50/50) nonwoven fabric for kerosene/soybean oil [21.09/27.01 (g oil/g sorbent)] was 1.5-2 times higher than those of commercial PP pad oil sorbents. The highest synergy effect of PP/kapok blend (50/50) was ascribed to the lowest bulk density of PP/kapok blend (50/50), which might be due to the highest morphologically incompatibility between PP fibre and kapok. These results suggest that the PP/kapok blend (50/50) having the highest synergy effect has a high potential as a new high-performance oil sorbent material.

Crizotinib in patients with anaplastic lymphoma kinase-positive advanced non-small cell lung cancer versus chemotherapy as a first-line treatment.

PubMed

Zhou, Jianya; Zheng, Jing; Zhang, Xiaochen; Zhao, Jing; Zhu, Yanping; Shen, Qian; Wang, Yuehong; Sun, Ke; Zhang, Zeying; Pan, Zhijie; Shen, Yihong; Zhou, Jianying

2018-01-03

To compare the efficacy of crizotinib, pemetrexed and other chemotherapy regimens as a first-line treatment in patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) in real world clinical use and to evaluate the +86-571-87,236,876 predictive clinical factors of the efficacy of crizotinib. The 73 patients with ALK-positive advanced NSCLC were divided into three groups based on the first-line treatment: first-line crizotinib group (1-CRZ group, n = 32); first-line platinum-based pemetrexed treatment group (1-PP group, n = 28), and first-line chemotherapy platinum-based non-pemetrexed group (N1-PP, n = 12). Sixty eight of the 73 patients received crizotinib treatment and followed up in our hospital. Differences in the objective response rate (ORR), disease control rate (DCR) and progression-free survival (PFS) were compared in the different groups. The clinical factors were evaluated to predict the efficacy of crizotinib by the Kaplan-Meier survival analysis and Cox proportional hazards model. The PFS, ORR, DCR were 16.1 months, 78.1% (25/32) and 100% (32/32) in the 1-CRZ group; were 6.0 months, 17.9% (5/28) and 57.2% (16/28) in the 1-PP group; and were 2.9 months, 15.4% (2/13) and 46.2% (6/13) in the N1-PP group. The PFS of the 1-CRZ group was significantly longer than that of the 1-PP group (P < 0.001) and the N1-PP group (P < 0.001). The ORR and DCR of the 1-CRZ group was significantly greater than that of the 1-PP group and the N1-PP group (all the P < 0.001). Higher Eastern Cooperative Oncology Group (ECOG) performance status score (> = 2) (HR 2.345, 95% CI 1.137-4.834, P = 0.021) and patients received crizotinib after N1-PP chemotherapy (HR 2.345, 95% CI 1.137-4.834, P = 0.021) were two factors associated with shorter PFS after crizotinib treatment. In patients with ALK-positive NSCLC who did not receive previous treatment, crizotinib was superior to standard chemotherapy for the longer PFS and greater ORR and DCR. Higher ECOG score (> = 2) and patients received crizotinib after N1-PP chemotherapy predict poor efficacy of crizotinib.