bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence that chlorpromazine and prostaglandin E1 but not neomycin interfere with the inositol phospholipid metabolism in intact human platelets
Authors: Tysnes Ole-Bjørn , Steen Vidar M. , Frølich Karin W. , Holmsen Holm
Published: July 2002

Human platelets that had been prelabelled with [32P]Pi were stimulated with trombin in the presence or absence of neomycin, prostaglandin E1 (PGE1) or chlorpromazine. The content of [32P]Pi in phosphatidylinositol 4‐phosphate, phosphatidylinositol 4,5‐bisphosphate and phosphatidic acid (PA) were determined. The data demonstrate that PGE1 and chlorpromazine but not neomycin interfere with the tight metabolic relationship that exists between the inositol phospholipids and PA in thrombin‐stimulated platelets [(1989) Biochem. J. 263, 621‐624]. Our results therefore indicate that neomycin does not inhibit signal transduction in intact platelets at the level of the inositol phospholipid metabolism.
Slow release of chloride from 36Cl‐labeled photosystem II membranes
Authors: Lindberg Katrin , Wydrzynski Tom , Vänngård Tore , Andréasson Lars-Erik
Published: July 2002

Photosystem II (PS II) membrane fragments isolated from spinach cultured on a medium containing 36Cl− retain a significant amount of radioactive chloride corresponding to at least one Cl− per PS II unit. The release of chloride from these sites occurs with halftimes of several hours. Treatments which cause the release of the manganese and/or the extrinsic proteins also result in the loss of chloride from these sites, indicating a possible role for this chloride in photosynthetic oxygen evolution.
Association of brain spectrin isoforms with microtubules
Authors: Riederer B.M. , Goodman S.R.
Published: July 2002

The relationship of rat brain spectrin isoforms to microtubules of newborn and adult animals was studied. Spectrins were minor components in microtubule preparations. The microtubule‐associated spectrin is a major calmodulin‐binding protein. Radiolabelled brain spectrin(240/235) revealed specific microtubule binding activity in vitro, possibly via a tubulin.
Factors influencing the formation of modified S2 EPR signal and the S3 EPR signal in Ca2+‐depleted photosystem II
Authors: Boussac Alain , Zimmermann Jean-Luc , Rutherford A.William
Published: July 2002

NaCl/EGTA‐washing of photosystem II (PS‐II) results in the removal of Ca2+ and the inhibition of oxygen evolution. Two new EPR signals were observed in such samples: a stable and modified S2 multiline signal and an S3 signal [(1989) Biochemistry 28, 8984‐8989]. Here, we report what factors are responsible for the modifications of the S2 signal and the observation of the S3 signal. The following results were obtained, (i) The stable, modified, S2 multiline signal can be induced by the addition of high concentrations of EGTA or citrate to PS‐II membranes which are already inhibited by Ca2+‐depletion. (ii) The carboxylic acids act in the S3‐state, are much less effective in S2 and have no effect in the S1‐state. (iii) The extrinsic polypeptides (17‐ and 23‐kDa) are not required to observe either the modified S2 signal or the S3 signal. However, they do influence the splitting and the lifetime of the S3 signal, and they seem to have a slight influence on the hyperfine pattern of the S2 signal, (iv) The S3 signal can be observed in Ca2+‐depleted PS‐II which does not exhibit the modified multiline signal. Then, it is proposed that formation of histidine radical during the S2 to S3 transition in Ca2+ ‐depleted PS‐II [(1990) Nature 347, 303‐306] also occurs in functional PS‐II.
Iron detoxifying activity of ferritin
Authors: Cozzi Anna , Santambrogio Paolo , Levi Sonia , Arosio Paolo
Published: July 2002

Three recombinant human apoferritin variants were added to ferrous iron and the amount of lipid peroxidation produced by hydrogen peroxide was studied. The H‐apoferritin had the strongest inhibitory effect on lipid peroxidation, probably due to its ferroxidase activity. The L‐apoferritin inhibited lipid peroxidation slowly and only at neutral pH. The H‐mutant 91, deleted of the last 22 C‐terminal amino acids, and which is not able to form an iron core, had minimal effects on iron lipid peroxidation. It was concluded that both ferro‐oxidase and iron mineralization activities are necessary for ferritin iron detoxifying action.
Molecular changes in the sarcoplasmic reticulum calcium ATPase during catalytic activity
Authors: Barth Andreas , Kreutz Werner , Mäntele Werner
Published: July 2002

Fourier transform infrared spectroscopy was used to study ligand binding and conformational changes in the Ca2+‐ATPase of sarcoplasmic reticulum. Novel in infrared difference spectroscopy, the catalytic cycle in the IR sample was started by photolytic release of ATP from an inactive, photolabile ATP‐derivative (caged ATP). Small, but characteristic infrared absorbance changes were observed upon ATP release. On the basis of model spectra, the absorbance changes corresponding to the trigger and substrate reactions, i.e. to photolysis of caged ATP and hydrolysis of ATP, were separated from the absorbance changes due to the active ATPase reflecting formation of the phosphorylated Ca2E1P enzyme form. A major rearrangement of ATPase conformation as the result of catalysis can be excluded.
Nuclear factor‐1 (NF‐1) binds to multiple sites within the transcriptional enhancer of Moloney Murine Leukemia virus
Authors: Reisman David
Published: July 2002

The transcriptional enhancer of the Moloney Murine Leukemia virus (Mo‐MuLV) is comprised of a 75‐bp direct repeat, each of which contains multiple binding sites for transcription factors. The occupancy of these sites determines the tissue specificity of expression and disease tropism of the virus. The identification of proteins that bind to this enhancer is therefore required in order to understand the molecular basis of this viral‐host interaction. Analysis of the nucleic acid sequence of the Mo‐MuLV has identified 4 potential binding sites for the transcription factor NF‐1. Evidence is presented using DNase I protection analysis that NF‐1 binds to these 4 sites within the enhancer. The potential role of NF‐1 binding in tissue specific expression of Mo‐MuLV is discussed.
Oxidized low‐density lipoprotein is chemotactic for arterial smooth muscle cells in culture
Authors: Autio Ismo , Jaakkola Olli , Solakivi Tiina , Nikkari Tapio
Published: July 2002

The effects of human native and Cu2+‐oxidized low‐density lipoprotein (LDL) were tested on the migration of cultured bovine aortic smooth muscle cells (SMCs) in blind‐well chambers. LDL oxidation was controlled by measuring the formation of conjugated dienes and lipid hydroperoxides, and by agarose gel electrophoresis. Oxidized LDL stimulated SMC migration, and the effect was dose‐dependent up to 200 . The stimulation was chemotactic in nature. Native LDL was without significant activity. The results suggest that oxidized LDL may contribute to the migration of medial SMCs into the intima during atherogenesis.
A high ratio of chromogranin A to synaptin/synaptophysin is a common feature of brains in Alzheimer and Pick disease
Authors: Weiler Rosa , Lassmann Hans , Fischer Peter , Jellinger Kurt , Winkler Hans
Published: July 2002

Chromogranin A and synaptin/synaptophysin were characterized by immunological methods in human autopsy brain tissue from patients with Alzheimer's and Pick's disease. In immunoblots there was no qualitative difference between the antigens in control and diseased brain, but significant quantitative differences were found. In all Alzheimer cases there was a significantly lower level of synaptin/synaptophysin, whereas chromogranin A was higher in 4 out of 5 cases and in all cases relative to synaptin/synaptophysin. An analogous findingwas obtained for Pick's disease. Immunohistologically a consistent staining of neuritic plaques for chromogranin A, but not for secretogranin II was found in Alzheimer cases. In Pick's disease the characteristic Pick bodies showed an analogous specific immunostaining.
A ring of uncharged polar amino acids as a component of channel constriction in the nicotinic acetylcholine receptor
Authors: Imoto Keiji , Konno Takashi , Nakai Junichi , Wang Feng , Mishina Masayoshi , Numa Shosaku
Published: July 2002

The channel pore of the nicotinic acetylcholine receptor (AChR) has been investigated by analysing single‐channel conductances of systematically mutatedTorpedo receptors expressed in Xenopus oocytes. The mutations mainly alter the size and polarity of uncharged polar amino acid residues of the acetylcholine receptor subunits positioned between the cytoplasmic ring and the extracellular ring. From the results obtained, we conclude that a ring of uncharged polar residues comprising threonine 244 of the α‐subunit (αT244), βS250, γT253 and δS258 (referred to as the central ring) and the anionic intermediate ring, which are adjacent to each other in the assumed α‐helical configuration of the M2‐containing transmembrane segment, together form a narrow channel constriction of short length, located close to the cytoplasmic side of the membrane. Our results also suggest that individual subunits, particularly the γ‐subunit, are asymmetrically positioned at the channel constriction.
Characterization of full‐length cDNAs and the gene coding for the human GM2 activator protein
Authors: Klima Horst , Tanaka Akemi , Schnabel Doris , Nakano Takeshi , Schröder Maria , Suzuki Kunihiko , Sandhoff Konrad
Published: July 2002

Full‐length cDNAs coding for the human GM2‐activator protein has been isolated and characterized, and its genomic structure studied in two overlapping clones in λ‐EMBL‐4 isolated from a human brain genomic library. Two different cDNAs were found that were identical to the 5′‐terminus to nt 1311 (counted from the A of the initiation codon, ATG) including the entire protein coding sequence. However, they were entirely dissimilar in the 3′‐non‐coding sequences. The genomic clones covered 94% of the full‐length cDNA sequence. Three introns were found. The last exon spans contiguously the carboxyl terminus of the protein and the entire 3′‐untranslated region of one of the two cDNAs with different 3′‐ends. The origin of the 3′‐portion of the other cDNA clone is not clear at this time.
Activation of adenylate cyclase in cdc25 mutants of Saccharomyces cerevisiae
Authors: Pardo Luis A. , Lazo Pedro S. , Ramos Sofia
Published: July 2002

The activation of adenylate cyclase by guanine nucleotides and 6‐deoxyglucose was studied in membrane preparations from S. cerevisiae mutants lacking the CDC25 gene product. Adenylate cyclase from cdc25 ts membranes was activated by GTP and GppNHp in membranes from cells collected after glucose was exhausted from the medium. The activation was also observed in membranes from repressed cells at 2.5 mM Mg2+. It is also shown that 6‐deoxyglucose can activate adenylate cyclase in the absence of CDC25 gene product. The relative amount of membrane‐bound adenylate cyclase was drastically reduced in cdc25 ts membranes when subjected to the restrictive temperature, while no significant change was observed in the wild type. These data suggest that Cdc25 might not be required in certain conditions for the guanine nucleotide exchange reaction in Ras and that it might be implicated in anchoring the Ras/adenylate cyclase system to the plasma membrane.
Biogenesis of lysosomal membranes
Authors: Peters Christoph , von Figura Kurt
Published: July 2002

Lysosomal membrane glycoproteins are highly glycosylated proteins decorating the luminal surface of lysosomal membranes. Their biosynthetic route from the rough endoplasmic reticulum to the lysosomal compartment has been elucidated during recent years. Signals for intracellular sorting have been identified and characterized. The function of these proteins remains to be determined. Besides resident proteins the lysosomal membrane harbours at least one transient passenger, lysosomal acid phosphatase, which is sorted as a membrane‐bound precursor like resident lysosomal membrane proteins and liberated from the membrane by limited proteolysis upon arrival in dense lysosomes.
Quinoline anti‐malarial drugs inhibit spontaneous formation of β‐haematin (malaria pigment)
Authors: Egan Timothy J. , Ross David C. , Adams Paul A.
Published: July 2002

Polymerisation of haematin to β‐haematin (haemozoin or malaria pigment) in acidic acetate solutions was studied using infrared spectroscopy. The reaction was found to occur spontaneously between 6 and 65°C, in 0.1–4.5 M acetate and pH 4.2–5.0. The anti‐malarial drugs quinine, chloroquine and amodiaquin were found to block spontaneous β‐haematin formation, while the anti‐malarially inactive 9‐epiquinine and 8‐hydroxyquinoline had no effect on the reaction, as did primaquine, a drug which is active only against exo‐erythrocytic stages of infection. It is argued that the intra‐erythrocytically active anti‐malarial agents act by binding to haematin, blocking β‐haematin formation and leaving toxic haematin in the parasite food vacuoles.
A novel pancreatic β‐cell isoform of calcium/calmodulin‐dependent protein kinase II (β3isoform) contains a proline‐rich tandem repeat in the association domain
Authors: Urquidi Virginia , Ashcroft Stephen J.H.
Published: July 2002

There is evidence for a role for calciumlcalmodulin‐dependent protein phosphorylation in regulation of insulin secretion but the molecular nature of the kinase(s) responsible is unknown. In this study, the screening of a neonatal rat islet cDNA library resulted in the isolation of a 2 kb clone that was 99% homologous to the β′ isoform of calciumlcalmodulin‐dependent protein kinase 11. The predicted 589 amino acid sequence with a caLculated mass of 64,976 Da contained a 24 amino acid deletion in addition to the 15 amino acid deletion that differentiates the β′ from the β isoform, and included an 86 amino acid novel domain consisting of a tandem repeat of proline‐rich residues. The expression of this new isoform of calciumlcalmodulin‐dependent protein kinase 11 (β3) was confirmed in β‐cell lines and testis by DNA amplification of the sequence encoding the inserted domain by reverse transcriptase‐polymerase chain reaction, followed by Southern analysis.
Pulmonary surfactant‐associated polypeptide SP‐C in lipid micelles: CD studies of intact SP‐C and NMR secondary structure determination of depalmitoyl‐SP‐C(1–17)
Authors: Johansson Jan , Szyperski Thomas , Wüthrich Kurt
Published: July 2002

The surfactant‐associated polypeptide C (SP‐C) is a 35‐residue lipopolypeptide which is essential for the function of surfactants used for therapy of infant respiratory distress. Modeling based on the recently determined nuclear magnetic resonance (NMR) structure of native SP‐C in an organic solvent showed that SP‐C could readily insert into fluid 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine bilayers. The present paper describes further physical‐chemical studies of intact SP‐C and its N‐terminal 17‐residue polypeptide fragment, depalmitoyl‐SPC(1–17), in the presence of dodecylphosphocholine micelles. The results obtained provide a link between the NMR solution structure and the behaviour of SP‐C in an ordered lipid environment, and thus present new insights for rational design of SP‐C analogs for therapeutic purposes.
The GLUT4 glucose transporter and the α2 subunit of the Na+,K+‐ATPase do not localize to the same intracellular vesicles in rat skeletal muscle
Authors: Lavoie Louis , He Lijing , Ramlal Toolsie , Ackerley Cameron , Marette André , Klip Amira
Published: July 2002

The GLUT4 glucose transporter and the α
2 subunit of the Na+,K+‐ATPase of rat skeletal muscle are two proteins which redistribute from intracellular membranes to plasma membranes following in vivo insulin stimulation. Here we show that although both proteins co‐segregate after subcellular fractionation of unstimulated rat hindlimb muscles, they do not share the same intracellular residence inside the muscle fibre. By immunogold single‐ and double‐labeling on ultrathin muscle cryosections with specific antibodies, the GLUT4 glucose transporter and the Na+,K+‐ATPase α
2 subunit were observed on different vesicular structures within the cell. GLUT4 was detected on subsarcolemmal and perinuclear membranes, and at the junction between myofibrillar A and I bands where triads are localized. The α
2 subunit of the Na+,K+‐ATPase was observed at the plasma membrane and in distinct subsarcolemmal vesicles and intermyofibrillar membranes. Quantitative analysis of double‐labeling of GLUT4 and Na+,K+‐ATPase α
2 subunit revealed that less than 6% of the two proteins co‐localize in the same continuous vesicular structures. The differential intracellular localization of the two proteins was further confirmed by immunopurification of GLUT4‐containing membranes from muscle homogenates, in which the α
2 subunit of the Na+,K+‐ATPase was found only at the same extent as the α
1 subunit of the enzyme, a protein exclusively present at the plasma membrane.
Nitric oxide is involved in heat‐induced HSP70 accumulation
Authors: Malyshev I.Yu. , Manukhina E.B. , Mikoyan V.D. , Kubrina L.N. , Vanin A.F.
Published: July 2002

Heat shock potentiated the nitric oxide production (EPR assay) in the liver, kidney, heart, spleen, intestine, and brain. The heat shock‐induced sharp transient increase in the rate of nitric oxide production preceded the accumulation of heat shock proteins (HSP70) (Western blot analysis) as measured in the heart and liver. In all organs the nitric oxide formation was completely blocked by the NO‐synthase inhibitor Nω‐nitro‐L‐arginine (L‐NNA). L‐NNA also markedly attenuated the heat shock‐induced accumulation of HSP70. The results suggests that nitric oxide is involved in the heat shock‐induced activation of HSP70 synthesis.
FTIR spectroscopy shows weak symmetric hydrogen bonding of the QB carbonyl groups in Rhodobacter sphaeroides R26 reaction centres
Authors: Brudler R. , de Groot H.J.M. , van Liemt W.B.S. , Gast P. , Hoff A.J. , Lugtenburg J. , Gerwert K.
Published: July 2002

The absorption frequencies of the C = O and C = C (neutral state) and of the C̲⋯O (semiquinone state) stretching vibrations of QB have been assigned by FTIR spectroscopy, using native and site‐specifically 1‐, 2‐, 3‐ and 4‐13C‐labelled ubiquinone‐10 (UQ10) reconstituted at the QB binding site of Rhodobacter sphaeroides R26 reaction centres. Besides the main C = O band at 1641 cm−1, two smaller bands are observed at 1664 and 1651 cm−1. The smaller bands at 1664 and 1651 cm−1 agree in frequencies with the 1‐ and 4‐C = O vibrations of unbound UQ10, showing that a minor fraction is loosely and symmetrically bound to the protein. The larger band at 1641 cm−1 indicates symmetric H‐bonding of the 1‐ and 4‐C = O groups for the layer fraction of UQ10 but much weaker interaction as for the 4‐C = O group of QA The FTIR experiments show that different C = O protein interactions contribute to the factors determining the different functions of UQ10 at the QA and the QB binding sites.
Characterization and functional dissection of the galactin‐1 gene promoter
Authors: Salvatore Paola , Contursi Cristina , Benvenuto Giovanna , Bruni Carmelo Bruno , Chiariotti Lorenzo
Published: July 2002

The galectin‐1 gene encodes a β‐galactoside‐binding protein whose overexpression is associated with neoplastic transformation and loss of differentiation. Transient transfection assays of a series of deletions constructs (pGAT) showed that the galectin‐1 promoter is highly active in cells both expressing and non‐expressing the endogenous gene, and that the basal activity is determined by sequences encompassing the transcription start site (). Both an upstream () and a downstream position‐dependent () cis‐elements are necessary for efficient transcriptional activity and are able to bind nuclear proteins.
Identification of the amino acid residues involved in selective agonist binding in the first extracellular loop of the δ‐ and μ‐opioid receptors
Authors: Fukuda Kazuhiko , Terasako Kiyoshi , Kato Shigeshisa , Mori Kenjiro
Published: July 2002

Effects of amino acid substitutions in the first extracellular loop region of the β‐ and μ‐opioid receptors were examined. Substitution of lysine‐108 of the δ‐receptor (δK108) with asparagine improved affinity to [d‐Ala2,MePhe4,Gly‐ol5]enk ephalin (DAGO), a μ‐selective peptide agonist, to be comparable with that of the μ‐receptor. On the other hand, replacement of mN127 with lysine decreased the affinity to DAGO by ∼ 15‐fold. These results suggest that dK108 and mN127, which correspond to each other in the aligned amino acid sequences, mainly determine the difference in DAGO binding affinity between the δ‐ and μ‐receptors.
CPP32 inhibition prevents Fas‐induced ceramide generation and apoptosis in human cells
Authors: Gamen Susana , Marzo Isabel , Anel Alberto , Piñeiro Andrés , Naval Javier
Published: July 2002

Intracellular activation of sphingomyelinase, leading to ceramide generation, and ICE‐like proteases have been implicated in TNF and Fas‐induced apoptosis, but the links between these intracellular apoptotic mediators remain undefined. We show here that a specific peptide inhibitor of the ICE‐like protease CPP32/Yama (DEVD‐cho) blocks anti‐Fasinduced apoptosis in Jurkat and U937 cells, while having no effect on TNF‐induced apoptosis in U937 cells. This peptide also prevents ceramide accumulation induced by Fas engagement. Jurkat and U937 cells, as well as their mtDNA‐depleted derived lines (π° cells), were sensitive to ceramide toxicity, which was not prevented by ICE‐like protease inhibitors. These results, taken together, suggest that ICE‐like protease activation is a prerequisite for ceramide generation and subsequent apoptosis, at least in the case of Fas‐induced cell death.
Phosphorylation of dynamin by ERK2 inhibits the dynamin‐microtubule interaction
Authors: Earnest Svetlana , Khokhlatchev Andrei , Albanesi Joseph P. , Barylko Barbara
Published: July 2002

In the present study we show that purified bovine brain dynamin can be phosphorylated by MAP kinase, ERK2, with a stoichiometry of 1 mol phosphate/mol dynamin. The phosphorylated serine residue is located within the C‐terminal 10 kDa of dynamin. Dynamin I phosphorylated by ERK2 can be specifically dephosphorylated by calcineurin but not by protein phosphatase 2A (PP2A). Phosphorylation of dynamin by ERK2 weakens the binding of dynamin to microtubules and inhibits dynamin's microtubule‐activated GTPase activity. Stimulation of GTPase activity by either Grb2 or phospholipids was not affected by ERK2 phosphorylation, suggesting that the binding sites for Grb2 and phospholipids do not overlap with that for microtubules.
Enhanced survival and differentiation in vitro of different neuronal populations by some interleukins
Authors: Moroni Stefano Casanova , Rossi Adelaide
Published: July 2002

Data from the literature demonstrate the existence of a growing family of neuropoietic cytokines; members of this group have structural motifs in common with other members and with neurotrophic factors. In this research we studied the responses elicited in vitro by some of these molecules in two different neuronal populations: murine neuroblastoma N18TG2 and neurons from chicken dorsal root ganglia. Both IL‐2 and IL‐6 improve the survival of murine neuroblastoma cells in clonal density plating experiments; in addition IL‐2 significantly inhibits thymidine incorporation by single cell suspension. The survival of sensory neurons, on the other hand, non‐responsive to IL‐2 and IL‐6, was significantly supported by IL‐3, which also stimulates their morphological differentiation, inducing the formation of a well‐developed neural net. In conclusion, results reported here confirm the neurotrophic activity of some ILs and provide additional neuronal models for future investigations.
Characterization of a novel endopolygalacturonase fromAspergillus nigerwith unique kinetic properties
Authors: Pařenicová Lucie , Kester Harry C.M. , Benen Jacques A.E. , Visser Jaap
Published: July 2002

We isolated and characterized a new type of endopolygalacturonase (PG)‐encoding gene,pgaD, fromAspergillus niger. The primary structure of PGD differs from that of otherA. nigerPGs by a 136 amino acid residues long N‐terminal extension. Biochemical analysis demonstrated extreme processive behavior of the enzyme on oligomers longer than five galacturonate units. Furthermore, PGD is the onlyA. nigerPG capable of hydrolyzing di‐galacturonate. It is tentatively concluded that the enzyme is composed of four subsites. The physiological role of PGD is discussed.
Peroxynitrite activates mitogen‐activated protein kinase (MAPK) via a MEK‐independent pathway: a role for protein kinase C
Authors: Bapat S , Verkleij A , Post J.A
Published: July 2002

In this study we show that phosphorylation of extracellular signal‐regulated kinase (ERK1/2; also known as p44/42MAPK) following peroxynitrite (ONOO−) exposure occurs via a MAPK kinase (MEK)‐independent but PKC‐dependent pathway in rat‐1 fibroblasts. ONOO−‐mediated ERK1/2 phosphorylation was not blocked by MEK inhibitors PD98059 and U0126. Furthermore, no increase in MEK phosphorylation was detected upon ONOO− treatment. Staurosporine was used to investigate whether protein kinase C (PKC) is involved. This was confirmed by down‐regulation of PKC by phorbol‐12,13‐dibutyrate, which resulted in significant reduction of ERK1/2 phosphorylation by ONOO−, implying that activation of ERK by ONOO− depends on activation of PKC. Indeed, PKCα and ϵ were activated upon ONOO− exposure. When cells were treated with ONOO− in a calcium‐free buffer, no activation of PKCα was detected. Concomitantly, a reduction of ERK1/2 phosphorylation was observed suggesting that calcium was required for translocation of PKCα and ERK phosphorylation by ONOO−. Indeed, ONOO− exposure resulted in increased cytosolic calcium, which depended on the presence of extracellular calcium. Finally, data using Gö6976, an inhibitor of calcium‐dependent PKC activation, implied that ONOO−‐mediated ERK1/2 phosphorylation depends on activation of a calcium‐dependent PKC.
CD spectroscopy provides evidence for excitonic interactions involving red‐shifted chlorophyll forms in photosystem I
Authors: Engelmann E. , Tagliabue T. , Karapetyan N.V. , Garlaschi F.M. , Zucchelli G. , Jennings R.C.
Published: July 2002

Selective destruction of the strongly dichroic red‐shifted chlorophyll form (C709 nm) in photosystem I (PSI) trimers from Spirulina, by either non‐selective high intensity illumination (photobleaching) or incubation with low concentrations of Triton X‐100 is accompanied by changes in the circular dichroism spectrum of the same amplitude and of opposite sign at 677 nm. The data are interpreted in terms of a dimeric chlorophyll structure with excitonic bands at these two wavelengths. Similar photobleaching experiments with PSI‐200 from maize also suggest the presence of bulk antenna/red form excitonic interactions.
Is an ATPase involved in uncoating of plasma membrane adaptor complex AP‐2?
Authors: Sosa Miguel A , Bertini Francisco , von Figura Kurt , Hille-Rehfeld Annette
Published: July 2002

The coat of clathrin‐coated vesicles mostly consists of clathrin and adaptor complexes AP‐1 or AP‐2. Clathrin is released from the vesicles in an ATP‐dependent fashion prior to their fusion with endosomes. In the present study we found that ATP strongly inhibits in vitro binding of cytosolic AP‐2 to membranes of stripped vesicles, and promotes the release of endogenous AP‐2 from clathrin‐deprived coated vesicles. Both effects required hydrolysis of ATP. In contrast, binding of AP‐1 to stripped vesicles was not affected by ATP, but was enhanced by GTP‐γ‐S. These results point to an ATPase that promotes the release of AP‐2 from clathrin‐coated vesicles.
Iron triggers a rapid induction of ascorbate peroxidase gene expression in Brassica napus
Authors: Vansuyt Gérard , Lopez Félicie , Inzé Dirk , Briat Jean-Francois , Fourcroy Pierre
Published: July 2002

In plants, only ferritin gene expression has been reported to be iron‐dependent. Here it is demonstrated that an iron overload of Brassica napus seedlings causes a large and rapid accumulation of ascorbate peroxidase transcripts, a plant‐specific hydrogen peroxide‐scavenging enzyme. This result documents a novel link between iron metabolism and oxidative stress. The ascorbate peroxidase mRNA abundance was not modified by reducing agents like N‐acetyl cysteine, glutathione and ascorbate or by pro‐oxidants such as hydrogen peroxide or diamide. Furthermore, the iron‐induced ascorbate peroxidase mRNA accumulation was not antagonized by N‐acetyl cysteine. Abscisic acid had no effect on the ascorbate peroxidase gene expression. Taken together these results suggest that iron‐mediated expression of ascorbate peroxidase gene occurs through a signal transduction pathway apparently different from those already described for plant genes responsive to oxidative stress.
Recombinant human glycosylasparaginase catalyzes hydrolysis of l‐asparagine
Authors: Noronkoski Tiina , Stoineva Ivanka B. , Petkov Dimiter D. , Mononen Ilkka
Published: July 2002

Glycosylasparaginase is a lysosomal amidase involved in the degradation of glycoproteins. Recombinant human glycosylasparaginase is capable of catalyzing the hydrolysis of the amino acid l‐asparagine to l‐aspartic acid and ammonia. For the hydrolysis of l‐asparagine the K
m is 3–4‐fold higher and V
max 1/5 of that for glycoasparagines suggesting that the full catalytic potential of glycosylasparaginase is not used in the hydrolysis of the free amino acid. l‐Asparagine competitively inhibits the hydrolysis of aspartylglucosamine indicating that both the amino acid and glycoasparagine are interacting with the same active site of the enzyme. The hydrolytic mechanism of l‐asparagine and glycoasparagines will be discussed.
Regulation of capsular polysialic acid biosynthesis by temperature in Pasteurella haemolytica A2
Authors: Barrallo Sofia , Reglero Angel , Revilla-Nuin Beatriz , Martı́nez-Blanco Honorina , Rodrı́guez-Aparicio Leandro B , Ferrero Miguel A
Published: July 2002

The capsular polysaccharide of Pasteurella haemolytica A2 consists of a linear polymer of N‐acetylneuraminic acid (Neu5Ac) with α(2–8) linkages. The production of this polymer is strictly regulated by the growth temperature and above 40°C no production is detected. Analysis of the enzymatic activities directly involved in its biosynthesis reveals that Neu5Ac lyase, CMP‐Neu5Ac synthetase and polysialyltransferase are involved in this regulation. Very low activities were found in P. haemolytica grown at 43°C (at least 25 times lower than those observed when the growth temperature was 37°C). The synthesis of these enzymes increased rapidly when bacteria grown at 43°C were transferred to 37°C and decreased dramatically when cells grown at 37°C were transferred to 43°C. These findings indicate that the cellular growth temperature regulates the synthesis of these enzymes and hence the concentration of the intermediates necessary for capsular polysaccharide genesis in P. haemolytica A2.
A missense mutation in the seventh transmembrane domain constitutively activates the human Ca2+ receptor
Authors: Zhao Xin-mei , Hauache Omar , Goldsmith Paul K. , Collins Regina , Spiegel Allen M.
Published: July 2002

A missense mutation, A843E, in the seventh transmembrane domain of the human Ca2+ receptor, identified in a subject with autosomal dominant hypocalcemia, was found to cause a constitutive activation while at the same time lowering the maximal response of the receptor to Ca2+. A truncated human Ca2+ receptor lacking the majority of the N‐terminal extracellular domain failed to respond to Ca2+ despite an excellent cell surface expression. The A843E mutant version of this truncated receptor showed constitutive activation. These results identify A843 as a critical residue for maintaining the inactive conformation of the human Ca2+ receptor. Substitution of glutamate, but not lysine or valine, for alanine 843 leads to activation of the human Ca2+ receptor in a manner that no longer depends upon Ca2+ binding to the extracellular domain.
Induction of apoptosis by human amylin in RINm5F islet β‐cells is associated with enhanced expression of p53 and p21WAF1/CIP1
Authors: Zhang Shaoping , Liu Junxi , Saafi ‘Etuate L. , Cooper Garth J.S.
Published: July 2002

Human amylin (10 μM) significantly inhibited RINm5F islet β‐cell proliferation and evoked apoptosis associated with typical degenerative ultrastructural changes and DNA fragmentation, whereas rat amylin did not. Time course analysis showed that human amylin elicited apoptosis in a passage‐dependent manner. Expression of the apoptosis‐related genes p53, bcl‐2 and WAF1/CIP1 was examined using Northern blots. mRNAs corresponding to p53 and to p21WAF/CIP1 were remarkably increased following human amylin treatment, whereas no change in bcl‐2 was detected. Our data suggest a role of p53 and p21 in human amylin‐induced β‐cell apoptosis. Furthermore, cells with higher proliferative potential (lower passage) were found to be more susceptible to apoptosis and to induction of p53, suggesting that β‐cells with different proliferation rates respond differently to human amylin, and that human amylin may be more toxic to proliferating cells.
Glial somatostatin‐14 expression in the rat pituitary intermediate lobe: a possible neurotrophic function during development?
Authors: Chronwall Bibie M. , Sands Scott A. , Cummings Kenneth C. , Schwartz Joan P.
Published: July 2002

Somatostatin‐14 was first detected on gestational day 17 in radially‐oriented, bipolar cells spanning the width of the intermediate lobe of the rat pituitary. Cells were prominent, and constituted approximately 50% of the lobe area. The presence of vimentin, the cellular shape, and the localization identified these cells as glia. At postnatal day 6, somatostatin‐14 and vimentin staining appeared in stellate‐shaped cells. This is in agreement with the change from bipolar to stellate shape these glia undergo after the onset of innervation ([13] Gary et al. Int. J. Devl. Neurosci. 13, 555–565, 1995). Glia were more abundant, relative to melanotropes, throughout embryonic and early postnatal development compared to adulthood. Reverse transcription‐polymerase chain reaction data showed a high level of prosomatostatin mRNA in the intermediate lobe, compared to the anterior and neural lobes from postnatal day 2 animals, and a significant drop in intermediate lobe content in the adult. The correlation between the number of glia and high expression of somatostatin in neonatal relative to adult tissue, together with the close apposition of incoming axons to the abundant, radially oriented glia during innervation of the lobe, support a neurotrophic function of glia‐derived somatostatin.
L1 and laminin : their expression during rathypophysis ontogenesis and in adult neurohemal areas
Authors: Berardi M. , Hindelang C. , Félix J.M. , Stoeckel M.E.
Published: July 2002

L1 is a murine multidomain glycoprotein implicated in cell aggregation, fasciculation,neurite outgrowth and synaptogenesis. Laminin, a trimeric polypeptide, is implicated in neuronalsurvival, growth cone guidance, neurite outgrowth and cell differentiation. Laminin can alsointeract with the cell adhesion molecule L1. Their expressions were investigated from embryonicday 15 (E15) to adult in the rat hypophysis, and in adult neurohemal zones.

Detected in the neural lobe from E17, the L1 immunoreactivity increased during prenataldevelopment and persisted in adulthood mainly related to the neuropeptidergic fibers. Pituicyteswere only labelled on the plasmalemma apposed to axons. In the intermediate lobe, L1 appearedat birth on folliculo‐stellate cells extensions, constituting a network which densified duringpostnatal development. L1 is also expressed in all neurohemal areas on neuronal profiles.

Laminin was clearly detectable in the hypophysis at E15 before the first blood vesselspenetrate the Rathke pouch. At E20, all the basal membranes of the blood vessels were stained. Inthe intermediate lobe, a spotted laminin immunoreactivity was detected at E21. At this stage, weobserved the staining of intercellular spaces and the intracellular labelling of melanotrophs,concerning reticulum or vesicles. The staining of melanotrophs seemed to maintain duringadulthood. In contrast with blood vessels of the adult cerebral tissue, adult capillaries of the neurallobe and the others neuro‐hemal zones were intensely labelled with the anti‐laminin antibody.

These results suggest that neurite outgrowth and neurite guidance could be promoted byL1 and laminin in the neurointermediate lobe. The intercellular tunnels could also be an importantguidance cue for migrating cells in the intermediate lobe. These data also demonstrate thatmelanotrophic cells, secreting the laminin, have a role in the ontogenesis of the gland. Finally, wesuggest that L1 and laminin can collaborate to reinforce neurons‐capillaries interactions inneurohemal zones.
Glioma cell migration is associated with glioma‐induced angiogenesis in vivo
Authors: Vajkoczy P. , Goldbrunner R. , Farhadi M. , Vince G. , Schilling L. , Tonn J.C. , Schmiedek P. , Menger M.D.
Published: July 2002

To simultaneously assess glioma cell invasion and glioma angiogenesis in vivo by non‐invasive and quantitative means, DiI‐labeled C6 glioma spheroids were implanted into the dorsal skinfold chamber preparation of nude mice (n=6). Heat‐inactivated spheroids served as controls to distinguish between active and passive cell spread. Using multi‐flourescent intravital videomicroscopy, glioma cell migration was analyzed on days 1–4, 6, and 10 and spheroid vascularization was analyzed on days 3, 6, and 10 after implantation. Additionaly, C6 glioma spheroids were implanted into the chronic cranial window of nude mice as an orthotopic implantation site (n=4). In the dorsal skinfold chamber, spheroids were vascularized within 10 days and revealed a tumor‐specific microvasculature. In parallel, individual glioma cells detached from the spheroid edge and migrated centrifugally demonstrating an affinity to tumor and host vessels. Glioma cells demonstrated a heterogeneous pattern of their regional migratory actvity (0.2–9.6 μm/h) which correlated well with regional glioma angiogenesis (r=0.733). Using the cranial window, glioma cells spread similarily demonstrating an affinity to the perivascular space of pial/subpial vessels with preference to the arteriolar segments. Intravital fluorescence microscopy represents a versatile technique to assess the complex relationship between glioma‐driven angiogenesis and glioma cell invasion.
Property, power, and the presidency: ownership policy reform and Russian executive–legislative relations, 1990–1999
Authors: Barnes Andrew
Published: July 2002

This article asks how new rules of political conduct are established in a country attempting political transformation and sweeping economic change. Based on a close analysis of the conflict over property policy and its effect on Russian executive–legislative relations in the 1990s, the study argues that regardless of formal distributions of power, the real allocation of policy-making authority is shaped in struggles over substantive policy issues. Those arenas, especially during the first years after the fall of an authoritarian regime, can function as “political classrooms” in which leaders either adopt or reject such practices as compromise and negotiation.
The Internet in the personal finance course
Authors: Woerheide Walt
Published: July 2002

A revolution is occurring as textbook authors struggle with how to effectively incorporate the Internet into the personal finance textbooks and course. This paper considers three questions associated with this revolution. What is the current degree of Internet integration? Where might we be headed with this new technology? Will this integration make for a better course? The current degree of Internet integration is reported in Tables 1 and 2. An argument is made that we may be headed to an eventual elimination of the textbook, as we know it. There is some preliminary evidence that this will make for a better educational experience. © 1999 Elsevier Science Inc. All rights reserved.
Beliefs and actions
Authors: Elder Harold W. , Rudolph Patricia M.
Published: July 2002

To understand the interaction of savings behavior, pension fund participation and expectations of retirement well being, we ask two questions. Are expected pension benefits a substitute for accumulated savings in replacing preretirement income? Are individuals’ expectations concerning their retirement standard of living realistic based on their accumulated savings and pension plan participation? First-wave data from the Health and Retirement Study (HRS) are analyzed using a probit regression. The results are consistent with the idea that pension benefits are substitutes for saving and that accumulated savings have a significant impact on the expected standard of living but pension plan participation does not. © 2000 Elsevier Science Inc. All rights reserved.
Design considerations for large public sector defined contribution plans
Authors: SigRist Kevin W. , Brown Stewart L.
Published: July 2002

The paper identifies differences between private (401 (k)) plans, which have evolved under ERISA and existing public plans, which have not. Examination of model legislation reveals that public plans should largely conform to ERISA going forward and reflect best practices in the private sector. Empirical analysis of equity mutual funds with $1.8 trillion in assets and institutional equity accounts with $98 billion in assets demonstrates efficiencies in separately procured institutional investment, administrative and educational services relative to retail investment products. The analysis points to tension between the duties of trustees and the demands of participants requesting large numbers of retail investment options. © 2001 Elsevier Science Inc. All rights reserved.
Strategic asset allocation for individual investors
Authors: Fraser Steve P. , Jennings William W. , King David R.
Published: July 2002

This paper demonstrates the dramatic effect of Social Security wealth on individuals’ asset allocation. We first discuss why Social Security wealth should be included in portfolio asset-mix decisions. We then draw parallels between Social Security benefits and inflation-indexed treasury bonds to help quantify the present value of Social Security benefits. Finally, we show the portfolio impact of including Social Security wealth under several asset-mix decision rules. Excluding Social Security wealth from the asset mix decision results in suboptimal portfolios. Including Social Security wealth provides an incentive for including more stock in the asset mix. © 2001 Elsevier Science Inc. All rights reserved.
The reliability of the book-to-market ratio as a risk proxy
Authors: Trecartin Jr. Ralph R.
Published: July 2002

This study examines whether the book-to-market ratio consistently explains the cross-section of stock returns through time. The results reveal that the book-to-market ratio is positively and signif- icantly related to return in only 43% of the monthly regressions. Other value/growth variables such as Cash Flow,” “Sales Growth,” and “Size”; perform even more erratically than the book-to-market ratio, and are thus less likely to be viewed as legitimate risk proxies. © 2001 Elsevier Science Inc. All rights reserved.
Asset Allocation and Investment Horizon
Authors: Smith Keith V.
Published: July 2002

Quarterly recommendations by national brokeragefirms since the third quarter of 1989 provide an opportunity to compare different approaches to asset allocation. To follow a brokerage firm’s recommendation every quarter is to practice tactical asset alloca- tion. Both the length of the investor’s decision horizon and brokerage commissions that are incurred when portfolio changes are made impact investment performance, and both contribute to the risk experienced by investors. Buy-and-hold and strategic asset allocation would have served investors better than tactical asset allocation during the first half of the 1990s.
Addendum
Authors: Lahey Karen Eilers
Published: July 2002

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From the Editor Vol 7 No 3
Authors: Lahey Karen Eilers
Published: July 2002

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The Wall Street Journal Interactive Edition internet site
Authors: Kahl Douglas
Published: July 2002

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Book Reviews
Authors: Kahl Douglas
Published: July 2002

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Comment on Kenneth S. Bigel’s Paper
Authors: Goss Robert P.
Published: July 2002

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Managing college tuition inflation using a surplus framework methodology
Authors: Russell Judson W. , Brooks Robert
Published: July 2002

This paper explores prepaid college tuition plans and develops a methodology for managing college tuition inflation. A surplus framework methodology is derived that employs various securities and incorporates both the assets and liabilities associated with prepaid college tuition plans. Although we present a methodology for plan management, the approach is applicable for individuals who manage their own college investment accounts. An interesting result of this analysis is that U.S. Treasury inflation-indexed securities should be included in the asset allocation decision for college tuition inflation management. By incorporating both the assets and liabilities from the plans into a surplus framework methodology, this paper provides a new portfolio management tool for plan administrators and individuals. Our assertion is that better managed plans offer more college financing alternatives for individuals. © 1999 Elsevier Science Inc. All rights reserved.
The golgin family exhibits a propensity to form condensates in living cells
Authors: Ziltener Pascal , Rebane Aleksander A. , Graham Morven , Ernst Andreas M. , Rothman James E.
Published: July 2020

The Golgi is surrounded by a ribosome‐excluding matrix. Recently, we reported that the cis‐Golgi‐localized golgin GM130 can phase‐separate to form dynamic, liquid‐like condensates in vitro and in vivo. Here, we show that the overexpression of each of the remaining cis (golgin160, GMAP210)‐ and trans (golgin97, golgin245, GCC88, GCC185)‐golgins results in novel protein condensates. Focused ion beam scanning electron microscopy (FIB‐SEM) images of GM130 condensates reveal a complex internal organization with branching aqueous channels. Pairs of golgins overexpressed in the same cell form distinct juxtaposed condensates. These findings support the hypothesis that, in addition to their established roles as vesicle tethers, phase separation may be a common feature of the golgin family that contributes to Golgi organization.
Phosphorylation of the N‐terminal domain of ribosomal P‐stalk protein uL10 governs its association with the ribosome
Authors: Filipek Kamil , Michalec‐Wawiórka Barbara , Boguszewska Aleksandra , Kmiecik Sebastian , Tchórzewski Marek
Published: July 2020

The uL10 protein is the main constituent of the ribosomal P‐stalk, anchoring the whole stalk to the ribosome through interactions with rRNA. The P‐stalk is the core of the GTPase‐associated center (GAC), a critical element for ribosome biogenesis and ribosome translational activity. All P‐stalk proteins (uL10, P1, and P2) undergo phosphorylation within their C termini. Here, we show that uL10 has multiple phosphorylation sites, mapped also within the N‐terminal rRNA‐binding domain. Our results reveal that the introduction of a negative charge within the N terminus of uL10 impairs its association with the ribosome. These findings demonstrate that uL10 N‐terminal phosphorylation has regulatory potential governing the uL10 interaction with the ribosome and may control the activity of GAC.