falciparum serine hydroxymethyltransferase: Topics by WorldWideScience.org

Role of Calcium in Serine Transport into Tobacco Cells

Cytoadherence or sequestration is essential for the pathogenesis of the most virulent human malaria species, Plasmodium falciparum (P. falciparum). Similar to leukocyte-endothelium...Full Text Available

var gene transcription and PfEMP1 expression in the rosetting and cytoadhesive Plasmodium falciparum clone FCR3S1.2

The transport of serine into tobacco (Nicotiana tabacum L. var. Xanthi) cells grown in liquid medium was studied. Serine transport was maximal below pH 4.0. A time-dependent stimulation...Full Text Available

1978-12-01

The relationship between the Plasmodium falciparum parasite ratio in childhood and climate estimates of malaria transmission in Kenya

BackgroundThe pathogenicity of Plasmodium falciparum is in part due to the ability of the parasitized red blood cell (pRBC) to adhere to intra-vascular host cell...Full Text Available

The Dynamics of Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs230 & Pfs48/45 in a Low Endemic Area in Tanzania

BackgroundPlasmodium falciparum morbid and fatal risks are considerably higher in areas supporting parasite prevalence ≥25%, when compared with low transmission...Full Text Available

Sensitivity of Plasmodium falciparum to chloroquine and sulfadoxine/pyrimethamine in Nigerian children.

BackgroundNaturally acquired immune responses against sexual stages of P. falciparum can reduce the transmission of malaria from humans to mosquitoes. These antigens...Full Text Available

Population genetic analysis of large sequence polymorphisms in Plasmodium falciparum blood-stage antigens

The in vivo sensitivity of Plasmodium falciparum to chloroquine and sulfadoxine/pyrimethamine was evaluated in children under 5 years of age in two areas of southern Nigeria in 1987. A modification...Full Text Available

1990-01-01

Hypoglycaemia and severe plasmodium falciparum malaria among pregnant sudanese women in an area characterized by unstable malaria transmission

Plasmodium falciparum, the causative agent of human malaria, invades host erythrocytes using several proteins on the surface of the invasive merozoite, which have been proposed...Full Text Available

2010-03-01

Diagnosis of Plasmodium falciparum infection using a solid-phase radioimmunoassay for the detection of malaria antigens

BackgroundPregnant women are more susceptible to severe Plasmodium falciparum malaria, which can lead to poor maternal and fetal outcomes. Few data exist on the...Full Text Available

Contrasting Population Structures of the Genes Encoding Ten Leading Vaccine-Candidate Antigens of the Human Malaria Parasite, Plasmodium falciparum

A serodiagnostic test has been developed for the detection of Plasmodium falciparum in infected blood. Using parasite antigens and infected red blood cells from in vitro...Full Text Available

1980-01-01

Common variation in the ABO glycosyltransferase is associated with susceptibility to severe Plasmodium falciparum malaria

The extensive diversity of Plasmodium falciparum antigens is a major obstacle to a broadly effective malaria vaccine but population genetics has rarely been used to guide vaccine design....Full Text Available

Blood Group A Antigen Is a Coreceptor in Plasmodium falciparum Rosetting

There is growing epidemiological and molecular evidence that ABO blood group affects host susceptibility to severe Plasmodium falciparum infection. The high frequency of common...Full Text Available

2008-02-15

The malaria parasite Plasmodium falciparum utilizes molecules present on the surface of uninfected red blood cells (RBC) for rosette formation, and a dependency on ABO antigens has...Full Text Available

2000-05-01

A prospective analysis of the Ab response to Plasmodium falciparum before and after a malaria season by protein microarray

Naturally acquired immunity to Plasmodium falciparum malaria in malaria holoendemic areas is characterized by the gradual, age-related development of protection against high-density...Full Text Available

Synthesis and characterization of a biotinylated organophosphorus ester for detection and affinity purification of a brain serine esterase: neuropathy target esterase.

Abs are central to malaria immunity, which is only acquired after years of exposure to Plasmodium falciparum (Pf). Despite the enormous worldwide burden of malaria,...Full Text Available

2010-04-13

Ixodes scapularis tick serine proteinase inhibitor (serpin) gene family; annotation and transcriptional analysis

We have synthesized a novel stable precursor, saligenin phosphorotrichloridate, which, on reaction with N-monobiotinyldiamines, generates a series of biotinylated covalent inhibitors of serine esterases....Full Text Available

1994-07-15

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

BackgroundSerine proteinase inhibitors (Serpins) are a large superfamily of structurally related, but functionally diverse proteins that control essential proteolytic pathways in...Full Text Available

Phylogenomic analyses of malaria parasites and evolution of their exported proteins

PknB is a member of the newly discovered eukaryotic-like protein serine/threonine kinase (PSTK) family of proteins. The pknB gene was cloned and expressed in Escherichia coli....Full Text Available

1999-11-01

Efficacy of drug prophylaxis.

BackgroundPlasmodium falciparum is the most malignant agent of human malaria. It belongs to the taxon Laverania, which includes other ape-infecting Plasmodium...Full Text Available

Efficacy and safety of a fixed-dose oral combination of pyronaridine-artesunate compared with artemether-lumefantrine in children and adults with uncomplicated Plasmodium falciparum malaria: a randomised non-inferiority trial.

With the spread of chloroquine resistant Plasmodium falciparum the control of malaria has become increasingly complex. In recent years, particular concern has arisen over how best to prevent malaria...Full Text Available

1989-01-01

Antibodies from malaria-exposed pregnant women recognize trypsin resistant epitopes on the surface of Plasmodium falciparum-infected erythrocytes selected for adhesion to chondroitin sulphate A

PMID:20417857

2010-04-24

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DEFF Research Database (Denmark)

Udgivelsesdato: 2004-Sep-6

2004-01-01

Ribose metabolism and nucleic acid synthesis in normal and glucose-6-phosphate dehydrogenase-deficient human erythrocytes infected with Plasmodium falciparum.

Phosphomimetic mutation of the mitotically phosphorylated serine 1880 compromises the interaction of the transmembrane nucleoporin gp210 with the nuclear pore complex

The metabolism of pentose-phosphate was investigated in Plasmodium falciparum-infected normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient human red blood cells in vitro. 5'-Phosphoribosyl-1-pyrophosphate...Full Text Available

1986-04-01

British Library Electronic Table of Contents (United Kingdom)

The nuclear pore complexes (NPCs) reversibly disassemble and reassemble during mitosis. Disassembly of the NPC is accompanied by phosphorylation of many nucleoporins although the function of this is not clear. It was previously shown that in the transmembrane nucleoporin gp210 a single serine residue at position 1880 is specifically phosphorylated during mitosis. Using amino acid substitution combined with live cell imaging, time-lapse microscopy and FRAP, we investigated the role of serine 1880 in binding of gp210 to the NPC in vivo. An alanine substitution mutant (S1880A) was significantly more dynamic at the NPC compared to the wild-type protein, suggesting that serine 1880 is important for binding of gp210 to the NPC. Moreover a glutamate substitution (S1880E) closely mimicking phosphorylated serine specifically interfered with incorporation of gp210 into the NPC and compromised its post-mitotic ...

2007-07-15

Summary Background There is a need for new artemisinin-based combination therapies that are convenient, effective, and safe. We compared the efficacy and safety of pyronaridine-artesunate with that of artemether-lumefantrine for treatment of uncomplicated P falciparum malaria. Methods This phase 3, parallel-group, double-blind, randomised, non-inferiority trial was undertaken in seven sites in Africa and three sites in southeast Asia. In a double-dummy design, patients aged 3-60 years with uncomplicated P falciparum malaria were randomly assigned in a 2:1 ratio to receive pyronaridine-artesunate once a day or artemether-lumefantrine twice a day, orally for 3 days, plus respective placebo. Randomisation was done by computer-generated randomisation sequence in blocks of nine by study centre....

2010-01-01

Statistical properties of nucleotide clusters in DNA sequences*

Multiplicity of Plasmodium falciparum infection in asymptomatic children in Senegal: relation to transmission, age and erythrocyte variants

Using the complete genome of Plasmodium falciparum 3D7 which has 14 chromosomes as an example, we have examined the distribution functions for the amount of C or G and A or T consecutively...Full Text Available

2005-05-01

Measuring the efficacy of anti-malarial drugs in vivo: quantitative PCR measurement of parasite clearance

BackgroundIndividuals living in malaria endemic areas generally harbour multiple parasite strains. Multiplicity of infection (MOI) can be an indicator of immune status. However,...Full Text Available

Impact of Plasmodium falciparum infection on the frequency of moderate to severe anaemia in children below 10 years of age in Gabon

BackgroundArtemisinin-based combination therapy, currently considered the therapy of choice for uncomplicated Plasmodium falciparum malaria in endemic countries,...Full Text Available

Evaluation of the OptiMAL Test for Rapid Diagnosis of Plasmodium vivax and Plasmodium falciparum Malaria

BackgroundImproving the understanding of childhood malarial anaemia may help in the design of appropriate management strategies.MethodsA...Full Text Available

Efficacy of sulphadoxine-pyrimethamine with or without artesunate for the treatment of uncomplicated Plasmodium falciparum malaria in southern Mozambique: a randomized controlled trial

The development of rapid and specific diagnostic tests to identify individuals infected with malaria is of paramount importance in efforts to control the severe public health impact of this disease....Full Text Available

1998-01-01

Diagnostic comparison of malaria infection in peripheral blood, placental blood and placental biopsies in Cameroonian parturient women

BackgroundAn artemisinin-based combination therapy, artesunate (AS) plus sulphadoxine-pyrimethamine (SP), was compared to SP monotherapy to provide evidence of further treatment...Full Text Available

Deletion of the Plasmodium falciparum Merozoite Surface Protein 7 Gene Impairs Parasite Invasion of Erythrocytes?

BackgroundIn sub-Saharan Africa, Plasmodium falciparum malaria in pregnancy presents an enormous diagnostic challenge. The epidemiological and clinical relevance...Full Text Available

Comparative Transcriptional and Genomic Analysis of Plasmodium falciparum Field Isolates

Merozoite surface proteins have been implicated in the initial attachment to the host red blood cell membrane that begins the process of invasion, an important step in the life cycle of the malaria...Full Text Available

2008-12-01

An improved method for undertaking limiting dilution assays for in vitro cloning of Plasmodium falciparum parasites

Mechanisms for differential regulation of gene expression may underlie much of the phenotypic variation and adaptability of malaria parasites. Here we describe transcriptional variation among culture-adapted...Full Text Available

2009-10-01

Accumulation of Plasmodium berghei-Infected Red Blood Cells in the Brain Is Crucial for the Development of Cerebral Malaria in Mice?

BackgroundObtaining single parasite clones is required for many techniques in malaria research. Cloning by limiting dilution using microscopy-based assessment for parasite growth...Full Text Available

ABO blood group phenotypes influence parity specific immunity to Plasmodium falciparum malaria in Malawian women

Cerebral malaria is the most severe complication of human infection with Plasmodium falciparum. It was shown that Plasmodium berghei ANKA-induced cerebral malaria was...Full Text Available

2010-09-01

The Functional Role of Calcineurin in Hypertrophy, Regeneration, and Disorders of Skeletal Muscle

BackgroundBlood group O has been significantly associated with increased placental malaria infection in primiparae and reduced risk of infection in multiparae in the Gambia, an area...Full Text Available

Taking the plunge: integrating structural, enzymatic and computational insights into a unified model for membrane-immersed rhomboid proteolysis

Skeletal muscle uses calcium as a second messenger to respond and adapt to environmental stimuli. Elevations in intracellular calcium levels activate calcineurin, a serine/threonine phosphatase, resulting...Full Text Available

2010-01-01

Identification of protein phosphorylation sites within Ser/Thr-rich cluster domains using site-directed mutagenesis and hybrid linear quadrupole ion trap Fourier transform ion cyclotron resonance mass spectrometry

SYNOPSISRhomboid proteases are a fascinating class of enzymes that combine a serine protease active site within the core of an integral membrane protein. Despite having key roles...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

We describe a method for the analysis of multi-site phosphorylation in serine/threonine (Ser/Thr)-rich protein sequences. Site-specific mutagenesis was used to introduce tryptic cleavage sites in the serine glutamine/threonine glutamine cluster domain (SCD) of the human checkpoint protein kinase (Chk2). The mutant proteins were shown to autophosphorylate on residues that are inducibly phosphorylated when mammalian cells are exposed to ionizing radiation (serine 33/35, serine 516, threonine 68 and threonine 432). Five Ser/Thr clusters within the SCD were flanked by arginine or lysine residues to produce tryptic peptides for nanospray liquid chromatography (nanoLC)/linear quadrupole ion trap Fourier transform ion cyclotron resonance mass spectrometry. Phosphorylation sites were assigned usin...

2007-01-01

EhMAPK, the Mitogen-Activated Protein Kinase from Entamoeba histolytica Is Associated with Cell Survival

Chemical activation of MEK1 - a redox trigger for evaluating the effects of phosphorylation.

Mitogen Activated Protein Kinases (MAPKs) are a class of serine/threonine kinases that regulate a number of different cellular activities including cell proliferation, differentiation, survival and...Full Text Available

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Autoantibodies to BRAF, a new family of autoantibodies associated with rheumatoid arthritis

An approach to generate mimics of phosphorylated serine proteins chemically through site-specific sulfonation of cysteine is presented. This chemical modification is reversible in the presence of reducing agent and therefore is analogous to the kinase/phosphatase system used in nature. PMID:21717004

2011-06-30

Association of Protein Phosphatase 1?₁ with Spinophilin Suppresses Phosphatase Activity in a Parkinson Disease Model*

IntroductionBRAF (v raf murine sarcoma viral oncogene homologue B1) is a serine-threonine kinase involved in the mitogen-activated protein kinase (MAPK) signalling pathway, known...Full Text Available

2010-01-01

Association Study of Serine Racemase Gene with Methamphetamine Psychosis

Sustained nigrostriatal dopamine depletion increases the serine/threonine phosphorylation of multiple striatal proteins that play a role in corticostriatal synaptic plasticity, including Thr²⁸⁶...Full Text Available

2008-05-23

ATM-Dependent Phosphorylation of ATF2 Is Required for the DNA Damage Response

Experimental studies have demonstrated that not only dopaminergic signaling but also glutamatergic/NMDA receptor signaling play indispensable roles in the development of methamphetamine psychosis. Our...Full Text Available

2011-03-01

SummaryActivating transcription factor 2 (ATF2) is regulated by JNK/p38 in response to stress. Here, we demonstrate that the protein kinase ATM phosphorylates ATF2 on serines...Full Text Available

2005-05-27

?H2AX and cancer

Detection of free amino acids in proxies of marine aerosol by photoelectron resonance capture ionization aerosol mass spectrometry

Histone H2AX phosphorylation on a serine four residues from the carboxyl terminus (producing γH2AX) is a sensitive marker for DNA double-strand breaks (DSBs). DSBs may lead to cancer...Full Text Available

2008-12-01

British Library Electronic Table of Contents (United Kingdom)

Photoelectron resonance capture ionization aerosol mass spectrometry (PERCI-AMS) has been applied to the analysis of proxies for marine aerosols with and without ozone; proxies used were mixed oleic acid-amino acid particles. The mechanism of ion formation for serine (104 m/z), glutamic acid (146 m/z), and phenylalanine (164 m/z) was dissociative electron attachment. This corresponds to loss of the hydrogen atom only, allowing for straightforward identification of the free amino acids. No ozonolysis products for the free amino acids were observed, even at high concentrations of ozone (500 ppm for 19 s). The direct detection of a novel gas-phase hydrated anion, [serine + H2O-H]-, is described. These preliminary results suggest that PERCI-AMS may provide an effective, simple and direct onlin...

2008-01-01

T Cell Responses to the RTS,S/AS01_E and RTS,S/AS02_D Malaria Candidate Vaccines Administered According to Different Schedules to Ghanaian Children

Evaluation of the rapid diagnostic test SDFK40 (Pf-pLDH/pan-pLDH) for the diagnosis of malaria in a non-endemic setting

BackgroundThe Plasmodium falciparum pre-erythrocytic stage candidate vaccine RTS,S is being developed for protection of young children against...Full Text Available

An open randomized clinical trial in comparing two artesunate-based combination treatments on Plasmodium falciparum malaria in Nigerian children: artesunate/sulphamethoxypyrazine/pyrimethamine (fixed dose over 24 hours) versus artesunate/amodiaquine (fixed dose over 48 hours)

BackgroundThe present study evaluated the SD Bioline Malaria Ag 05FK40 (SDFK40), a three-band RDT detecting Plasmodium falciparum-specific parasite lactate dehydrogenase...Full Text Available

The Acidic Domain of Hepatitis C Virus NS4A Contributes to RNA Replication and Virus Particle Assembly?

BackgroundSeveral studies have demonstrated the efficacy of artemisinin-combination therapy (ACT) across malaria zones of the world. Fixed dose ACT with shorter courses and fewer...Full Text Available

Molecular basis of adult-onset and chronic GM2 gangliosidoses in patients of Ashkenazi Jewish origin: substitution of serine for glycine at position 269 of the alpha-subunit of beta-hexosaminidase.

Hepatitis C virus NS3-4A is a membrane-bound enzyme complex that exhibits serine protease, RNA helicase, and RNA-stimulated ATPase activities. This enzyme complex is essential for viral genome replication...Full Text Available

2011-02-01

Lysis of phespholipid membranes with radiation-induced free radicals

Chronic and adult-onset GM2 gangliosidoses are neurological disorders caused by marked deficiency of the A isoenzyme of beta-hexosaminidase; they occur in the Ashkenazi Jewish population, though less...Full Text Available

1989-04-01

LOC387715/HTRA1 gene polymorphisms and susceptibility to age-related macular degeneration: A HuGE review and meta-analysis

Phospholipid vesicles were found to be lysed by exposure to free radicals derived from irradiated glycine and galactose. The decomposition yield increased with vesicle concentration, and attained values of 0.0006 vesicles destroyed per radical added. Ionic charge at the phospholipid end groups was found to be more important than degree of unsaturation in determining this yield. Radicals derived from irradiated serine and alanine had no detectable lytic action at the vesicle concentrations tested.

1977-05-01

Hyperphosphorylation of the Rotavirus NSP5 Protein Is Independent of Serine 67 or NSP2, and the Intrinsic Insolubility of NSP5 Is Regulated by Cellular Phosphatases

PurposeTo examine the association of age-related macular degeneration (AMD) with HtrA serine peptidase 1 (HTRA1) gene rs11200638 G→A polymorphism and LOC387715/...Full Text Available

Crystal structures of the N-terminal kinase domain of human RSK1 bound to three different ligands: Implications for the design of RSK1 specific inhibitors

The NSP5 protein is required for viroplasm formation during rotavirus infection and is hyperphosphorylated into 32- to 35-kDa isoforms. Earlier studies reported that NSP5 is not hyperphosphorylated...Full Text Available

2006-02-01

Calmodulin Kinase II Interacts with the Dopamine Transporter C Terminus to Regulate Amphetamine-Induced Reverse Transport

The p90 ribosomal S6 kinases (RSKs) also known as MAPKAP-Ks are serine/threonine protein kinases that are activated by ERK or PDK1 and act as downstream effectors of mitogen-activated protein kinase...Full Text Available

2007-12-01

DEFF Research Database (Denmark)

Efflux of dopamine through the dopamine transporter (DAT) is critical for the psychostimulatory properties of amphetamines, but the underlying mechanism is unclear. Here we show that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) plays a key role in this efflux. CaMKIIalpha bound to the distal C terminus of DAT and colocalized with DAT in dopaminergic neurons. CaMKIIalpha stimulated dopamine efflux via DAT in response to amphetamine in heterologous cells and in dopaminergic neurons. CaMKIIalpha phosphorylated serines in the distal N terminus of DAT in vitro, and mutation of these serines eliminated the stimulatory effects of CaMKIIalpha. A mutation of the DAT C terminus impairing CaMKIIalpha binding also impaired amphetamine-induced dopamine efflux. An in vivo role for CaMKII was supported by chronoamperometry measurements showing reduced amphetamine-induced dopamine efflux in response to the CaMKII inhibitor KN93. Our data suggest that ...

2006-01-01

The influence of amino acids on the biomineralization of hydroxyapatite in gelatin.

Antiprotozoal and cytotoxic activities in vitro of Colombian Annonaceae

The effects of pH on the calcium phosphate phase, of Tris and of amino acids, such as aspartic acid, glutamic acid, and serine on hydroxyapatite formation and morphology, were studied in double diffusion experiments. In this system, hydroxyapatite was only formed when the pH was around 7.4 or higher for the duration of the reaction. A decrease in pH resulted in the transformation of hydroxyapatite to octacalcium phosphate. Amino acids and Tris or the buffering capacity of Tris have an effect on the morphology of the synthetic hydroxyapatite. The presence of the additive results in spheres consisting of needles, blades or plates depending on the reaction system. PMID:12175941

2002-08-30

British Library Electronic Table of Contents (United Kingdom)

Ethnobotanical and chemotaxonomical studies for antiparasitic activity of Colombian Annonaceae were carried out. In vitro antiprotozoal activity of 36 extracts obtained from six different species was determined against promastigotes of three Leishmania species, epimastigotes of Trypanosoma cruzi and both chloroquine sensitive (F32) and resistant (W2) Plasmodium falciparum. Cytotoxic activity was evaluated in U-937 cells. Active extracts were selected according their selectivity index (SI). Extracts from Annona muricata, Rollinia exsucca, Rollinia pittieri and Xylopia aromatica were active against Leishmania spp. and Trypanosoma cruzi showing IC50 values lower than 25mg/ml. Hexane extract from Rollinia pittieri leaves was the most selective against Trypanosoma cruzi and Leishmania spp. (IS=...

2007-01-01

Anti-plasmodial activity and toxicity of extracts of plants used in traditional malaria therapy in Meru and Kilifi Districts of Kenya

British Library Electronic Table of Contents (United Kingdom)

The methanol and aqueous extracts of 10 plant species (Acacia nilotica, Azadirachta indica, Carissa edulis, Fagaropsis angolensis, Harrissonia abyssinica, Myrica salicifolia, Neoboutonia macrocalyx, Strychnos heningsii, Withania somnifera and Zanthoxylum usambarensis) used to treat malaria in Meru and Kilifi Districts, Kenya, were tested for brine shrimp lethality and in vitro anti-plasmodial activity against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum (NF54 and ENT30). Of the plants tested, 40% of the methanol extracts were toxic to the brine shrimp (LD5050N. macrocalyx had the highest toxicity to brine shrimp nauplii (LD50 21.04+-1.8mg/ml). Methanol extracts of the rest of the plants exhibited mild or no brine shrimp toxicity (LD50>50mg/ml). The aqueo...

2006-01-01

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Synthetic enantiopure aziridinomitosenes: preparation, reactivity, and DNA alkylation studies.

Resveratrol causes COX-2- and p53-dependent apoptosis in head and neck squamous cell cancer cells

An enantiocontrolled route to aziridinomitosenes had been developed from l-serine methyl ester hydrochloride. The tetracyclic target ring system was assembled by an internal azomethine ylide cycloaddition reaction based on silver ion-assisted intramolecular oxazole alkylation and cyanide-induced ylide generation via a labile oxazoline intermediate (62 to 66). Other key steps include reductive detritylation of 26, methylation of the N-H aziridine 56, oxidation of the sensitive cyclohexenedione 68 to quinone 70, and carbamoylation using Fmoc-NCO. Although the aziridinomitosene tetracycle is sensitive, a range of protecting group manipulations and redox chemistry can be performed if suitable precautions are taken. A study of DNA alkylation by the first C-6,C-7-unsubstituted aziridinomitosene 11a has been carried out, and evidence for DNA cross-link formation involving nucleophilic addition to the quinone subunit is described. PMID:14677970

2003-12-24

British Library Electronic Table of Contents (United Kingdom)

Cyclooxygenase-2 (COX-2) content is increased in many types of tumor cells. We have investigated the mechanism by which resveratrol, a stilbene that is pro-apoptotic in many tumor cell lines, causes apoptosis in human head and neck squamous cell carcinoma UMSCC-22B cells by a mechanism involving cellular COX-2. UMSCC-22B cells treated with resveratrol for 24 h, with or without selected inhibitors, were examined: (1) for the presence of nuclear activated ERK1/2, p53 and COX-2, (2) for evidence of apoptosis, and (3) by chromatin immunoprecipitation to demonstrate p53 binding to the p21 promoter. Stilbene-induced apoptosis was concentration-dependent, and associated with ERK1/2 activation, serine-15 p53 phosphorylation and nuclear accumulation of these proteins. These effects were blocked by ...

2008-01-01

Mechanism of Dephosphorylation of the SR Protein ASF/SF2 by Protein Phosphatase 1

British Library Electronic Table of Contents (United Kingdom)

SR proteins are essential splicing factors whose function is controlled by multi-site phosphorylation of a C-terminal domain rich in arginine-serine repeats (RS domain). The protein kinase SRPK1 has been shown to polyphosphorylate the N-terminal portion of the RS domain (RS1) of the SR protein ASF/SF2, a modification that promotes nuclear entry of this splicing factor and engagement in splicing function. Later, dephosphorylation is required for maturation of the spliceosome and other RNA processing steps. While phosphates are attached to RS1 in a sequential manner by SRPK1, little is known about how they are removed. To investigate factors that control dephosphorylation, we monitored region-specific mapping of phosphorylation sites in ASF/SF2 as a function of the protein phosphatase PP1. W...

2010-01-01

Inhibition of the heterotetrameric K++ channel KCNQ1/KCNE1 by the AMP-activated protein kinase

British Library Electronic Table of Contents (United Kingdom)

Abstract The heterotetrameric K++-channel KCNQ1/KCNE1 is expressed in heart, skeletal muscle, liver and several epithelia including the renal proximal tubule. In the heart, it contributes to the repolarization of cardiomyocytes. The repolarization is impaired in ischemia. Ischemia stimulates the AMP-activated protein kinase (AMPK), a serine/threonine kinase, sensing energy depletion and stimulating several cellular mechanisms to enhance energy production and to limit energy utilization. AMPK has previously been shown to downregulate the epithelial Na++ channel ENaC, an effect mediated by the ubiquitin ligase Nedd4-2. The present study explored whether AMPK regulates KCNQ1/KCNE1. To this end, cRNA encoding KCNQ1/KCNE1 was injected into Xenopus oocytes with and without additional injection o...

2011-01-01

Increased osteoblast adhesion on nanograined Ti modified with KRSR

British Library Electronic Table of Contents (United Kingdom)

Peptide sequences such as lysine-arginine-serine-arginine (KRSR) selectively bind transmembrane proteoglycans (e.g. heparin sulfate) of osteoblasts (bone-forming cells) and are, therefore, actively being investigated for orthopedic applications. Further, nanophase materials (or materials with grain or particle sizes less than 100 nm) are promising new materials that promote new bone growth more than compared to conventional (that is, micron grain or particle size) materials. To combine the above two promising approaches for improving orthopedic implants, the objective of this in vitro study was to functionalize titanium (Ti) surfaces (both nanophase and conventional) with KRSR peptides and study their osteoblast cell adhesive properties. Materials were characterized by X-ray photoelectron ...

2007-01-01

Glycine metabolism by Pseudomonas aeruginosa: hydrogen cyanide biosynthesis

Serine-324 of myosin's heavy chain is photoaffinity-labeled by 3 prime (2 prime )-O-(4-benzoylbenzoyl)adenosine triphosphate

Hydrogen cyanide (HCN) production by Pseudomonas aeruginosa in a synthetic medium is stimulated by the presence of glycine. Methionine enhances this stimulation but will not substitute for glycine as a stimulator of cyanogenesis. Threonine and phenylalanine are effective substitutes for glycine in the stimulation of HCN production. Glycine, threonine, and serine are good radioisotope precursors of HCN, but methionine and phenylalanine are not. Cell extracts of P. aeruginosa convert (/sup 14/C)threonine to (/sup 14/C)glycine. H14CN is produced with low dilution of label from either (1-/sup 14/C)glycine or (2-/sup 14/C)glycine, indicating a randomization of label either in the primary or secondary metabolism of glycine. When whole cells were fed (1,2-/sup 14/C)glycine, cyanide and bicarbonate were the only radioactive extracellular products observed.

1977-05-01

TMPRSS6 rs855791 modulates hepcidin transcription in vitro and serum hepcidin levels in normal individuals.

A portion of the active site of rabbit skeletal myosin near the ribose ring of ATP can be labeled by the photoaffinity analogue 3{prime}(2{prime})-O-(4-benzoylbenzoyl)adenosine triphosphate (Bz{sub 2}ATP). The specificity of the photolabeling was assured by first trapping ({sup 14}C)Bz{sub 2}ATP at the active site by use of thiol cross-linking agents. Five radioactive peptides were isolated by high-performance liquid chromatography after extensive trypsin and subtilisin digestion of photolabeled myosin subfragment 1. Four of these peptides were sequenced by Edman techniques, and all originated from a region with the sequence Gly-Glu-Ile-Thr-Val-Pro-Ser-Ile-Asp-Asp-Gln, which corresponds to rabbit myosin heavy chain residues 312-328. The fifth labeled peptide had an amino acid composition appropriate for residues 312-328. Amino acid composition, radiochemical analysis, and sequence data indicate that Ser-324 is the major amino acid residue photolabeled by Bz{sub 2}ATP. ...

1989-05-02

Purification and partial characterization of glycosaminoglycans and proteoglycans from cultured rabbit smooth muscle cells

The iron hormone hepcidin is inhibited by matriptase-2, a liver serine-protease encoded by TMPRSS6 gene. Cleaving the BMP-coreceptor hemojuvelin, matriptase-2 impairs the BMP/SMAD signaling pathway, downregulates hepcidin and facilitates iron absorption. TMPRSS6 inactivation causes iron-deficiency-anemia refractory to iron administration both in humans and mice. Genome wide association studies have shown that the SNP rs855791, which causes the matriptase-2 V736A amino acid substitution, is associated with variations of serum iron, transferrin saturation, hemoglobin and erythrocyte traits. Here we show that in vitro matriptase-2 736(A) inhibits hepcidin more efficiently than 736(V). Moreover, in a genotyped population, after exclusion of samples with iron deficiency and inflammation, hepcidin, hepcidin/transferrin saturation and hepcidin/ferritin ratios were significantly lower and iron parameters were consistently higher in homozygotes 736(A) than in 736(V). Our ...

2011-08-26

Phosphorylation of proteins in Clostridium thermohydrosulfuricum

Glycosaminoglycans synthesized by cultured rabbit smooth muscle cells were isolated after incorporation of (/sup 3/H)-glucosamine into glycosaminoglycans in the presence or absence of 10% fetal bovine serum. Glycosaminoglycans were quantitated by two-dimensional electrophoresis after proteolytic digestion of the cell layers and media. The results show that the presence of serum has no effect on the chondroitin sulfate, heparan sulfate and dermatan sulfate content of the cell layers. The incorporation of (/sup 3/H)-glucosamine into hyaluronic acid of the cell layers was three times higher in the presence of serum. In the medium , the quantity of hyaluronic was two times higher in the presence of serum while the other glycosaminoglycans remained unchanged. The incorporation of (/sup 3/H)-glucosamine into hyaluronic acid was unaffected by the presence of serum. Specific proteoglycans were isolated from medium after with (/sup 35/S)-sulfate and (/sup 3/H)-serine by ...

1985-01-01

Molar extinction coefficients in aqueous solutions of some amino acids

Cell extracts of the thermophile Clostridium thermohydrosulfuricum catalyzed the phosphorylation by (..gamma..-/sup 32/P)ATP of several endogenous proteins with M/sub r/s between 13,000 and 100,000. Serine and tyrosine were the main acceptors. Distinct substrate proteins were found in the soluble (e.g., proteins p66, p63, and p53 of M/sub r/s 66,000, 63,000, and 53,000, respectively) and particulate (p76 and p30) fractions, both of which contained protein kinase and phosphatase activity. The soluble fraction suppressed the phosphorylation of particulate proteins and contained a protein kinase inhibitor. Phosphorylation of p53 was promoted by 10..mu..M fructose 1,6-bisphosphate or glucose 1,6-bisphosphate and suppressed by hexose monophosphates, whereas p30 and p13 were suppressed by 5 ..mu..M brain (but not spinach) calmodulin. Polyamines, including the odd polyamines characteristic of thermophiles, modulated the labeling of most of the phosphoproteins. Apart from ...

1986-02-01

In vivo phosphorylation of histones H1 and H5 in calf thymus and chicken erythrocytes as studied by /sup 31/P nuclear magnetic resonance spectroscopy

Mass attenuation coefficients of amino acids viz. glycerine (C_2H_5NO_2), 1-Serine (C_3H_7NO_3), 1-Theronine (C_4H_9NO_3), 1-Proline (C_5H_9NO_2), 1-Valine (C_5H_1_1NO_2) and 1-Phenylalanine (C_9H_1_1NO_2) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by the gamma-ray transmission method in a narrow beam good geometry setup. Precisely measured densities of these solutions were used for the determination of these coefficients which varied systematically with the corresponding changes in the concentrations (g/cm"3) of the solutions. Molar extinction coefficients of amino acids were then obtained at these energies and were found to be in good agreement with the theoretical results. In addition, total interaction cross sections of amino acids in aqueous solutions were also calculated. (author)

2002-09-01

Gene discovery in the Acanthamoeba castellanii genome

The /sup 31/P NMR method was first applied to characterize in vivo phosphorylation of H1 and H5 in calf thymus and chicken erythrocytes as well as in vitro phosphorylation of H1 and H5 by cAMP-dependent protein kinase. The amino acid residues phosphorylated in vivo in the histones were exclusively serine residues, and the mole fraction of phosphoserine was estimated to be 0.34 and 0.27 per molecule of calf thymus H1 and chicken erythrocyte H5, respectively. Interestingly, chicken erythrocyte H1 was not phosphorylated in vivo. Three H1 subtypes from calf thymus H1 varied in the /sup 31/P NMR spectra, and the bisected fragments of calf thymus H1 and chicken erythrocyte H5 exhibited characteristic spectral patterns, indicating that there are considerable diversities of the degree of phosphorylation and phosphorylation sites in very-lysine-rich histones. Furthermore, it was found that the microenvironment of phosphoserine residues phosphorylated in vivo in calf thymus ...

1987-08-01

Four small puzzles that Rosetta doesn't solve

Acanthamoeba castellanii is a free-living amoeba found in soil, freshwater, and marine environments and an important predator of bacteria. Acanthamoeba castellanii is also an opportunistic pathogen of clinical interest, responsible for several distinct diseases in humans. In order to provide a genomic platform for the study of this ubiquitous and important protist, we generated a sequence survey of approximately 0.5 x coverage of the genome. The data predict that A. castellanii exhibits a greater biosynthetic capacity than the free-living Dictyostelium discoideum and the parasite Entamoeba histolytica, providing an explanation for the ability of A. castellanii to inhabit adversity of environments. Alginate lyase may provide access to bacteria within biofilms by breaking down the biofilm matrix, and polyhydroxybutyrate depolymerase may facilitate utilization of the bacterial storage compound polyhydroxybutyrate as a food source. Enzymes for the synthesis and breakdown of cellulose were ...

2005-08-01

CERN Document Server

A complete macromolecule modeling package must be able to solve the simplest structure prediction problems. Despite recent successes in high resolution structure modeling and design, the Rosetta software suite fares poorly on deceptively small protein and RNA puzzles, some as small as four residues. To illustrate these problems, this manuscript presents extensive Rosetta results for four well-defined test cases: the 20-residue mini-protein Trp cage, an even smaller disulfide-stabilized conotoxin, the reactive loop of a serine protease inhibitor, and a UUCG RNA tetraloop. In contrast to previous Rosetta studies, several lines of evidence indicate that conformational sampling is not the major bottleneck in modeling these small systems. Instead, approximations and omissions in the Rosetta all-atom energy function currently preclude discriminating experimentally observed conformations from de novo models at atomic resolution. These molecular "puzzles" should serve as ...

2011-01-01

Effects of temperature and organic and inorganic nutrients on the growth of Chattonella marina (Raphidophyceae) from the Daya Bay, South China Sea

British Library Electronic Table of Contents (United Kingdom)

The effects of temperature and different forms of nutrients on Chattonella marina growth have been investigated in strains isolated from the Daya Bay, the South China Sea. The strain of C. marina preferred high temperatures, with an optimal temperature of 25?C, and 18?C was the minimum for its survival. Higher cell number and growth rate were obtained in high nitrogen and phosphorus concentrations (500 ?g/L, 74 ?g/L) than under nutrient limitation. Nitrogen influenced the growth most, as the specific growth rate and maximum cell density were lower in nitrogenlimited cultures than noted under phosphorus limitation or under limitation from both. C. marina was capable of using many kinds of organic nitrogen sources including L-serine (L-Ser), glycine (Gly), alanine (Ala), L-threonine (L-Thr),...

2011-01-01

Developments of PET radioligands for NMDA receptors

Stoichiometry of photorespiration during C3-photosynthesis is not fixed: evidence from combined physical and stereochemical methods

Aim: There has been a great demand for developments of the radioligands to visualize the N-methyl-D-aspartate (NMDA) receptors by PET/SPECT. We have recently synthesized two C-11 labeled antagonists for the glycine-binding site on NMDA receptors. The aim of this work is to examine for their in vitro and in vivo binding characteristics, and to evaluate their potentials as PET radioligands for the NMDA receptors. Materials and methods: Two C-11 labeled 4-hydroxy-2-quinolones (1 and 2) were synthesized by conventional methylation of the corresponding phenols with ["1"1C]methyl iodide. In vitro and ex vivo quantitative autoradiographs with imaging plate, as well as animal PET, were employed in order to evaluate their in vitro and in vivo binding to the NMDA receptors. Results: The compound 1 showed the specific binding to rat brain slices with higher localization in the hippocampus and cerebral cortex than in the cerebellum. Both glycine antagonists and agonists (glycine and ...

2002-09-01

Platelet receptor recognition domain on the. gamma. chain of human fibrinogen and its synthetic peptide analogues

The stoichiometry of photorespiration, S, is defined as the fraction of glycolate carbon photorespired. It is postulated that under steady-state conditions there are two determinants of the ratio of photorespiration to net photosynthesis: the partitioning of ribulose bisphosphate between oxidation and carboxylation, and the partitioning of glycolate between reactions leading to complete oxidation to CO/sub 2/ (S . 100%) and those yielding CO/sub 2/ plus serine (S . 25%). S may be calculated using two independent probes of the system. The physical probe, using an infrared gas analyzer, measured photorespiration and net photosynthesis, and hence their ratio PR/NPS . pn(phys). The metabolic probe employed tracer (3R)-D-(3-/sup 3/H1,3-/sup 14/C)glyceric acid to determine r, the fraction of /sup 3/H retained in the triose phosphates leaving the chloroplasts. It is deduced from the postulated model that S . pn(phys) . r/(1 - r). Experiments have been performed with ...

1985-03-01

Genome analysis of F. nucleatum sub spp vincentii and its comparison with the genome of F. nucleatum ATCC 25586.

The authors have shown previously that the domain recognizing receptors on activated human platelets is located on the human fibrinogen {gamma} chain between residues 400 and 411. To study the correlation between the structure of this segment of the {gamma} chain and its reactivity toward receptors on ADP-activated human platelets, they designed a series of analogues containing replacements at 9 out of 12 positions. A double substitution of the normal His{sup 400}-His{sup 401} sequence by Ala-Ala reduced the inhibitory potency of the dodecapeptide 3-fold. When Lys{sup 406} was replaced by Arg, the inhibitory potency of the dodecapeptide decreased 15 times. On the other hand, substitution of Ala{sup 408} with Arg increased the inhibitory potency of the dodecapeptide 6-fold. A drastic decrease in the reactivity of the dodecapeptide toward platelet receptors was observed when Val{sup 411} was replaced by leucine or cysteine or tyrosine. A 3-fold decrease in reactivity was noted when ...

1989-04-04

Genetic heterogeneity in type 1 Gaucher disease: Multiple genotypes in Ashkenazic and non-Ashkenazic individuals

We present the draft genome sequence and its analysis for Fusobacterium nucleatum sub spp. vincentii (FNV), and compare that genome with F. nucleatum ATCC 25586 (FN). A total of 441 FNV open reading frames (ORFs) with no orthologs in FN have been identified. Of these, 118 ORFs have no known function and are unique to FNV, whereas 323 ORFs have functional orthologs in other organisms. In addition to the excretion of butyrate, H2S and ammonia-like FN, FNV has the additional capability to excrete lactate and aminobutyrate. Unlike FN, FNV is likely to incorporate galactopyranose, galacturonate, and sialic acid into its O-antigen. It appears to transport ferrous iron by an anaerobic ferrous transporter. Genes for eukaryotic type serine/threonine kinase and phosphatase, transpeptidase E-transglycosylase Pbp1A are found in FNV but not in FN. Unique ABC transporters, cryptic phages, and three types of restriction-modification systems have been identified in FNV. ORFs for ...

2003-06-01

Dendroaspis natriuretic peptide and the designer natriuretic peptide, CD-NP, are resistant to proteolytic inactivation.

Nucleotide sequence analysis of a genomic clone from an Ashkenazic Jewish patient with type 1 Gaucher disease revealed a single-base mutation (adenosine to guanosine transition) in exon 9 of the glucocerebrosidase gene. This change results in the amino acid substitution of serine for asparagine. Transient expression studies following oligonucleotide-directed mutagenesis of the normal cDNA confirmed that the mutation results in loss of glucocerebrosidase activity. Allele-specific hybridization with oligonucleotide probes demonstrated that this mutation was found exclusively in type 1 phenotype. None of the 6 type 2 patients, 11 type 3 patients, or 12 normal controls had this allele. In contrast, 15 of 24 type 1 patients had one allele with this mutation, and 3 others were homozygous for the mutation. Furthermore, some of the Ashkenazic Jewish type 1 patients had only one allele with this mutation, suggesting that even in this population there is allelic ...

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Antimalarial activity of selected Sudanese medicinal plants with emphasis to Maytenus senegalensis

Designer natriuretic peptides (NPs) represent an active area of drug development. In canine and human studies, the designer natriuretic peptide CD-NP demonstrated more desirable therapeutic potential than recombinant B-type NP (BNP), which is known as nesiritide and is approved for treatment of acute decompensated heart failure. However, why CD-NP is more effective than BNP is not known. We previously reported that CD-NP is a poorer activator of human guanylyl cyclase-A (GC-A) and a better activator of human guanylyl cyclase-B than BNP. Here, guanylyl cyclase bioassays were used to compare the susceptibility of CD-NP verses ANP, BNP, CNP and DNP to inactivation by human kidney membranes. The half time (t(1/2)) for CD-NP inactivation was increased by factors of 13, 3 and 4 compared to ANP, BNP and CNP, respectively, when measured in the same assay. Surprisingly, DNP failed to undergo complete inactivation and was the most degradation resistant of the peptides tested. The neutral ...

2011-04-01