bluuebunny/crossref_metadata_2025 huggingface dataset:
Atomic force microscopy characterization of ultrathin polystyrene films formed by admicellar polymerization on silica disks
Authors: See Chun Hwa , O'Haver John
Published: April 2003

Atomic force microscopy was used to study the characteristics of polymer films formed via admicellar polymerization (the polymerization of monomers solubilized in adsorbed surfactant aggregates). The investigated system included cetyltrimethylammonium bromide (C16TAB) as a cationic surfactant, styrene, 2,2′‐azobisisobutyrilnitrile as an initiator, and polished silica disk substrates. Our goal was to examine changes in the properties and morphology of the formed polymer films due to changes in the surfactant and monomer feed levels. Normal tapping and phase‐contrast modes in air were used to image the nanoscopic and microscopic morphologies of the polystyrene‐modified silica. The root‐mean‐square roughness of the surface before and after modification was statistically analyzed and compared. The images were captured with loading‐force set‐point ratios of 0.2–0.9, and this allowed us to examine the stability of the polystyrene films. In the first series, for which the feed ratio of C16TAB to styrene was kept constant and the total feed concentration was varied, a uniform layer of a polystyrene film was observed along with some nanometer‐size aggregates at high feed concentrations of both C16TAB and styrene. These droplets eventually agglomerated with the film beneath and formed larger macrodroplets in a ring arrangement. At lower concentrations, droplets and holes were observed that eventually agglomerated to form a bicontinuous thin film. In the second experimental series, the concentration of C16TAB was kept constant, and the feed ratio of C16TAB to styrene was varied. A smooth thin film was observed at high concentrations of styrene. This film could be deformed and/or removed to expose the silica surface beneath. At lower styrene loadings, the polystyrene film became unstable and formed dropletlike aggregates, possibly because of either the uneven adsolubilization of the styrene monomer within the admicelle or the dewetting effect during washing and drying. The structure of the polystyrene film formed on a smooth silica disk was very dependent on the amount of the surfactant fed to the system; this contrasted with the results on precipitated silica. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 36–46, 2003
Caenorhabditis elegans—applications to nematode genomics
Authors: Gregory William F. , Parkinson John
Published: April 2003

The complete genome sequence of the free‐living nematode Caenorhabditis elegans was published 4 years ago. Since then, we have seen great strides in technologies that seek to exploit this data. Here we describe the application of some of these techniques and other advances that are helping us to understand about not only the biology of this important model organism but also the entire phylum Nematoda. Copyright © 2003 John Wiley & Sons, Ltd.
Towards interoperability in genome databases: the MAtDB (MIPS Arabidopsis thaliana database) experience
Authors: Schoof Heiko
Published: April 2003

Increasing numbers of whole‐genome sequences are available, but to interpret them fully requires more than listing all genes. Genome databases are faced with the challenges of integrating heterogenous data and enabling data mining. In comparison to a data warehousing approach, where integration is achieved through replication of all relevant data in a unified schema, distributed approaches provide greater flexibility and maintainability. These are important in a field where new data is generated rapidly and our understanding of the data changes. Interoperability between distributed data sources allows data maintenance to be separated from integration and analysis. Simple ways to access the data can facilitate the development of new data mining tools and the transition from model genome analysis to comparative genomics. With the MIPS Arabidopsis thaliana genome database (MAtDB, http://mips.gsf.de/proj/thal/db) our aim is to go beyond a data repository towards creating an integrated knowledge resource. To this end, the Arabidopsis genome has been a backbone against which to structure and integrate heterogenous data. The challenges to be met are continuous updating of data, the design of flexible data models that can evolve with new data, the integration of heterogenous data, e.g. through the use of ontologies, comprehensive views and visualization of complex information, simple interfaces for application access locally or via the Internet, and knowledge transfer across species. Copyright © 2003 John Wiley & Sons, Ltd.
Interdigitating dendritic reticulum cell tumor of lymph nodes: Case report with differential diagnostic considerations
Authors: Ylagan Lourdes R. , Bartlett Nancy L. , Kraus Madeleine
Published: April 2003

A 66‐yr‐old man with a history of interdigitating reticulum cell tumor (IDRCT) presented with an enlarging right cervical lymph node suspicious of recurrent disease. He reported no fevers or night sweats and was otherwise asymptomatic at the time of the fine‐needle aspiration (FNA). FNA of the lymph node showed a spindle cell lesion with plump, at times deeply convoluted, large nuclei, coarsely granular chromatin, with one or two distinct nucleoli, intimately associated with mature‐appearing lymphocytes. A cell block was made and immunohistochemistry was carried out. Immunopositivity for vimentin, S‐100, and CD68 and immunonegativity for CD21 and AE1/AE3 were noted. This case report is the first to illustrate the FNA cytomorphology of IDRCT and to discuss the cytologic differential diagnosis of this rare tumor type in lymph nodes. Diagn. Cytopathol. 2003;28:278–281. © 2003 Wiley‐Liss, Inc.
Synthesis of novel thia‐oxadiazolophanes
Authors: Chande M. S. , Godbole A. A. , Sajithkumar C.
Published: April 2003

The novel thia‐1,3,4‐oxadiazolophanes were synthesized regioselectively from 1,4‐bis(5‐mercapto‐1,3,4‐oxadiazol‐2‐yl)butane and various 1,ω‐dihaloalkanes in presence of potassium hydroxide. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:273–275, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10141
Allylation of aldiminomercaptotriazinones using allyl halides and allylmetal compounds
Authors: El‐Shehawy Ashraf A.
Published: April 2003

Allylation of 4‐amino‐3‐mercapto‐6‐methyl‐4H‐1,2,4‐triazin‐5‐one (1) and its arylideneamino derivatives 5 was performed through two different methods. Reaction of 1 and 5 with allylic bromides 2 in the presence of sodium ethoxide afforded a mixture of S‐ and N‐allylated products. Treatment of arylimines 5 with allylic zinc bromides 9 and triallylborane reagents 12 did not affect the hetero‐ring opening but the CN bond of the lateral chain underwent the addition reaction yielding the C‐allylated products 10. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:280–287, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10144
Modifications of polypropylene surface properties by He+ ion implantation
Authors: Brun C. , Fromm M. , Berger F. , Delobelle P. , Takadoum J. , Beche E. , Chambaudet A. , Jaffiol F.
Published: April 2003

A polypropylene (PP) modified by ethylene–propylene rubber (EPR) was treated in vacuo by α particles (with an energy of 400 keV) with fluences that varied from 1011 to 1016 He+ cm−2. Samples were investigated with attenuated total reflection Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, contact‐angle measurements, differential scanning calorimetry, swelling, nanoindentation, and friction techniques. After treatment, new chemical groups (carbonyl and vinyl bonds) appeared at the PP/EPR surface. These chemical modifications led to changes in the surface free energy of PP/EPR. Irradiation also modified the PP/EPR structure because crosslinking occurred after treatment for fluences above or equal to 5 × 1014 He+ cm−2. Moreover, the PP melting temperature and enthalpy were greatly decreased for fluences above or equal to 1014 He+ cm−2. The surface mechanical properties were also changed after treatment. Indeed, the friction coefficient decreased, whereas the hardness and Young's modulus drastically increased, after irradiation at higher fluences. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1183–1191, 2003
Entanglement and properties
Authors: Ghirardi G. , Marinatto L.
Published: April 2003

Various topics concerning the entanglement of composite quantum systems are considered with particular emphasis concerning the strict relations of such a problem with the one of attributing objective properties to the constituents. In particular we will focus our attention to composite quantum systems composed of identical constituents, with the purpose of dealing with subtle issues, which have never been adequately discussed in the literature, originating from the true indistinguishability of the subsystems involved.
Acaricidal activity of Uvaria Versicolor and Uvaria Klaineana (Annonaceae)
Authors: Akendengue B. , Ngou‐Milama E. , Bourobou‐Bourobou H. , Essouma J. , Roblot F. , Gleye C. , Laurens A. , Hocquemiller R. , Loiseau P. , Bories C.
Published: April 2003

Three Uvaria species, namely U. klaineana, U. mocoli and U. versicolor were tested in vitro against Dermatophagoides pteronyssinus, the European house dust mite. The most active extracts were the Uvaria versicolor stems crude methanol and hexane extracts with EC50 values of 0.095 g/m2 and 0.12 g/m2, respectively. The bioassay‐guided fractionation of the hexane extract led to the isolation of benzyl benzoate (1) which exhibited an EC50 value of 0.045 g/m2. A new ﬂavanone, versuvanone (2), and the known oxoaporphine liriodenine (3) were also isolated from this species and showed EC50 values > 1.5 g/m2. A weak acaricidal activity (0.85 g/m2) was observed for the dichloromethane extract of Uvaria klaineana, due to the presence of benzyl benzoate. Uvaria mocoli was inactive. The structures of compounds were elucidated using 2D‐NMR techniques. Copyright © 2003 John Wiley & Sons, Ltd.
Crown gall – a plant tumour with biological activities
Authors: Brantner A. H. , Asres K. , Chakraborty A. , Tokuda H. , Mou X. Y. , Mukainaka T. , Nishino H. , Stoyanova S. , Hamburger M.
Published: April 2003

Petroleum ether, acetone, 80% MeOH and water extracts of crown gall, a plant tumour, obtained from Eucalyptus globulus tree were screened for cytotoxic, antioxidant, antiinﬂammatory, embryotoxic, antitumour‐promoting and antimicrobial activities.

In terms of bioactivity the 80% MeOH extract was most effective followed by the acetone extract. The petroleum ether extract showed weak to moderate cytotoxic activity in dose‐dependent manner against PC12 cells, mouse L ﬁbroblasts and 1321N1 glia cells, whereas the hydroalcohol extract had no or a weak cytotoxic effect. The 80% MeOH extract exhibited strong antioxidant activity. Based on the in vitro HET‐CAM assay all the extracts were effective against inﬂammation. The extracts did not show any embryotoxic effect at the concentrations tested. Antitumour‐promoting activity (100% inhibition; 100 µg/mL) was observed in the 80% MeOH and acetone extracts. In the antimicrobial screening all extracts displayed predominantly antifungal activity against Candida sp. The extracts also showed various levels of antibacterial activity against E. faecalis, Ps. aeruginosa, Bac. subtilis and Staph. epidermidis.

From the results of the investigations it can be concluded that crown gall is a valuable plant tumour tissue having interesting biological activities. Copyright © 2003 John Wiley & Sons, Ltd.
cDNA cloning, biochemical and phylogenetic characterization of β‐ and β′‐subunits of Candida albicans protein kinase CK2
Authors: Zelada Alicia , De Souza Flávio S. J. , Walz Katherina , Giasson Luc , Passeron Susana
Published: April 2003

We have previously reported that Candida albicans protein kinase CK2 is composed of two distinct catalytic (α‐ and α′‐) and two distinct regulatory (β‐ and β′‐) subunits. We report here the isolation of two cDNAs clones, CaCKB1 and CaCKB2, encoding C. albicans β‐ and β′‐subunits, respectively. The predicted β‐ and β′‐proteins have calculated molecular masses of 34 kDa and 31 kDa and show all major features conserved in β‐subunits of other organisms, including the N‐terminal autophosphorylation site, the internal acidic region and a potential metal‐binding motif. The deduced amino acid sequence of C. albicans β‐subunit displays 48% identity with that of Saccharomyces cerevisiae and has an unusually long C‐terminal acidic region containing a putative autophosphorylation site. C. albicans β′ shows 54% sequence identity with its S. cerevisiae homologue. Semi‐quantitative RT–PCR analyses indicate that the mRNAs corresponding to both subunits are present in similar amounts in the yeast and hyphal forms of the fungus. To evaluate the biochemical properties of C. albicans β‐ and β′‐subunits, both proteins were expressed in Escherichia coli and purified. Experiments performed in vitro indicate that both recombinant subunits reconstitute a fully functional holoenzyme when incubated with stoichiometric amounts of human recombinant α‐subunit, as judged by their ability to abolish basal phosphorylation of calmodulin by human recombinant α‐subunit and the reversion of the inhibitory effect by polylysine. In addition, both regulatory subunits can be phosphorylated by human recombinant α subunit. Phylogenetic analysis of β‐ and β′‐proteins of C. albicans and other organisms shows that the CKB gene duplication occurred before the split of the ascomycete and basidiomycete lineages. cDNA sequences of C. albicans CKB1 (Accession No. AF0599060) and CKB2 (Accession No. AY172319) have been deposited in the GenBank database. Copyright © 2003 John Wiley & Sons, Ltd.
Intercellular channels in teleosts: functional characterization of two connexins from Atlantic croaker
Authors: Bruzzone Roberto , White Thomas W. , Yoshizaki Goro , Patiño Reynaldo , Paul David L.
Published: April 2003

Gap junction channels, composed of protein subunits termed connexins, are believed to play a critical role in the process of oocyte differentiation and maturation. We have used the pairedXenopusoocyte assay to characterize functionally two connexin genes, connexin‐32.2 and connexin‐32.7, recently cloned from the ovary of the Atlantic croaker (Micropogonia undulatus), a species that has emerged as a useful model to study the process of maturation of the ovarian follicle. We have found that, while both connexin proteins were expressed at comparable levels inXenopusoocytes, only one, connexin‐32.2, was functionally competent to induce the formation of intercellular channels. Connexin‐32.2 channels exhibited voltage‐dependent closure that was similar to, but distinct from that of previously characterized mammalian connexins. In addition, the silent connexin‐32.7 was unable to functionally interact with connexin‐32.2, either in heterotypic channels or as dominant negative inhibitor. Because connexin‐32.2 expression is strikingly regulated during oocyte maturation, these data provide further evidence for a role of intercellular channels in the control of oocyte‐follicular cell interactions.
Secondary structure and folding topology of the DNA binding domain of interferon regulatory factor 2, as revealed by NMR spectroscopy
Authors: Uegaki Koichi , Shirakawa Masahiro , Harada Hisashi , Taniguchi Tadatsugu , Kyogoku Yoshimasa
Published: April 2003

The secondary structure elements of the DNA‐binding domain of mouse interferon regulatory factor 2 [IRF‐2(113)] were determined by heteronuclear multidimensional NMR spectroscopy. The sequential NOE connectivities, amide proton exchange rates, and 3JHNα coupling constants indicated the presence of three α‐helical regions and four short β‐strands connected through relatively long loops. The long range NOEs indicated the four strands form an antiparallel β‐sheet and the three α‐helices form a bundle on the sheet. The arrangement of the secondary structure elements and the overall folding topology resemble those of the DNA binding domains of bacterial activator CAP, heat shock transcription factors, and fork‐head proteins, although there is no sequence homology among them.
Epidermal growth factor‐binding protein activates soluble and receptor‐bound single chain urokinase‐type plasminogen activator
Authors: Wolf Beni B. , Brown Morry D.
Published: April 2003

Epidermal growth factor‐binding protein (EGF‐BP) is a serine proteinase that reversibly associates with epidermal growth factor (EGF). We analyzed the reaction of EGF‐BP with urokinase type plasminogen activator (u‐PA), a serine proteinase that promotes pericellular proteolysis and cellular migration. EGF‐BP cleaved single chain u‐PA (scu‐PA) between Lys158 and Ile159, converting the zymogen into enzymatically active two‐chain u‐PA (tcu‐PA), as shown by SDS‐PAGE, N‐terminal sequence analysis, and enzymatic assay. The k
cat and K
m of the activation reaction were (5.6 ± 0.6) × 10−2
s
−1 and 2,0 ± 0.3 μM, yielding a catalytic efficiency of 2.8 × 104 M−1. EGF‐BP also activated scu‐PA bound to receptors on U937 monocytes as demonstrated by the generation of amidase activity against a tcu‐PA‐specific fluorogenic substrate. By activating scu‐PA, EGF‐BP may initiate u‐PA‐dependent cell surface proteolysis and therefore enhance EGF activities that require cellular migration and/or tissue remodeling.
Characterization of common neoantigenic epitopes generated in plasminogen activator inhibitor‐1 after cleavage of the reactive center loop or after complex formation with various serine proteinases
Authors: Debrock Sophie , Declerck Paul J.
Published: April 2003

Plasminogen activator inhibitor‐1 (PAI‐1), an important risk factor for thrombotic diseases, is a member of the superfamily of serine proteinase inhibitors. To define structural rearrangements occurring during interaction between PAI‐1 and its target proteinases we have raised monoclonal antibodies against the PAI‐1/t‐PA complex. Thirteen out of 401 monoclonal antibodies reacted preferentially with the PAI‐1/t‐PA complex as compared to free PAI‐1 or free t‐PA. Detailed characterization revealed the presence of two non‐overlapping neoantigenic epitopes in the PAI‐1/t‐PA complex. Both neoantigenic epitopes were also exposed after complex formation between PAI‐1 and either urokinase‐type plasminogen activator, plasmin or thrombin as well as after cleavage of the reactive site loop of non‐inhibitory substrate type PAI‐1 variants. Thus, we have identified two neoantigenic epitopes, localized entirely in PAI‐1, and commonly exposed after complex formation of active PAI‐1 with various proteinases or after cleavage of substrate PAI‐1. These monoclonal antibodies should facilitate further studies on the mechanism of interaction between various PAI‐1 forms and its target proteinases.
In situ dephosphorylation of tau by protein phosphatase 2A and 2B in fetal rat primary cultured neurons
Authors: Saito Taro , Ishiguro Koichi , Uchida Tsuneko , Miyamoto Eishichi , Kishimoto Takeo , Hisanaga Shin-ichi
Published: April 2003

Using antibodies recognizing the phosphorylation state of specific sites, phosphorylation states of tau were monitored in fetal rat primary cultured neurons. When cultured neurons were treated with okadaic acid (OA) or calyculin A (Ca1A) at concentrations sufficient to inhibit protein phosphatase 2A (PP2A), phosphorylation of Ser‐199/Ser‐202 (numbered according to the human tau 441) and Ser‐235 increased. On the other hand, treatment with Ca2+ ionophore, A23187, induced dephosphorylation of Ser‐199/Ser‐202, Thr‐205, Ser‐396 and Ser‐404, and this dephosphorylation was repressed by inhibitors of protein phosphatase 2B (PP2B), cyclosporin A and FK506. These results indicate that PP2A and PP2B are differentially involved in dephosphorylation of tau in neurons.
‘Thermodynamic’ mechanism of catalysis by haloperoxidases
Authors: Shevelkova Angelina N. , Sal'nikov Yury I. , Kuz'mina Natal'ya L. , Ryabov Alexander D.
Published: April 2003

A novel ‘thermodynamic’ mechanistic rationale of haloperoxidase catalysis is based on the following two assumptions: (i) the role of enzyme consists only in the rapid equilibration between the halogen‐containing species originating from halide and hydrogen peroxide; (ii) the interaction between the enzyme and organic substrate is kinetically insignificant and halogenation occurs as a result of the electrophilic attack of the active brominating (Br3
−, Br2 and HBrP) or chlorinating (HClO) species at monochlorodimedon indicative of a higher chloride ‘specificity’ of chloroperoxidase from C. fumago.
In vitro characterisation of Ro 46‐8443, the first non‐peptide antagonist selective for the endothelin ETB receptor
Authors: Breu Volker , Clozel Martine , Burri Kaspar , Hirth Georges , Neidhart Werner , Ramuz Henri
Published: April 2003

We describe here Ro 46‐8443, the first non‐peptide endothelin ETB receptor selective antagonist. It displays up to 2000‐fold selectivity for ETB receptors both in terms of binding inhibitory potency and functional inhibition. The observed parallel rightward shift of concentration‐response curves with different antagonist concentrations is consistent with a competitive binding mode. Since Ro 46‐8443 selectively inhibits ETB receptor mediated responses, it is a valuable tool for clarifying the role of ETB receptors in pathology.
Yeast aspartic protease 3 (Yap3) prefers substrates with basic residues in the P2, P1 and P2′ positions
Authors: Ledgerwood Elizabeth C. , Brennan Stephen O. , Cawley Niamh X. , Peng Loh Y. , George Peter M.
Published: April 2003

The yeast aspartic protease Yap3 is localised to the secretory pathway and correctly cleaves pro‐α‐mating factor at its dibasic sites. We determined the specificity of Yap3 for mono‐, di‐ and multi‐basic cleavage sites in the context of 15 residue synthetic proalbumin peptides. Yap3 cleaved after dibasic ArgArg and LysArg sites but not after monobasic Arg sites even when there was an additional arginine at −6 and/or −4. Yap3 did not cleave a tetra‐arginine site and tribasic sites (RRR and RRK) were poor substrates. Cleavage always occurred C‐terminal to the last arginine in the di‐ or tri‐basic sequence. The optimal cleavage site sequence was RR ↓ DR and this substrate was cleaved 8–9‐fold faster than the normal RR ↓ DA sequence. In contrast to Kex2, Yap3 did not remove the propeptide from normal proalbumin or a range of natural or recombinant proalbumin variants. However at pH 4.0 Yap3 slowly cleaved proalbumin and albumin between domains 2 and 3.
Significance of secondary structure predictions on the reactive center loop region of seprins: a model for the folding of serpins into a metastable state
Authors: Patston Philip A. , Gettins Peter G.W.
Published: April 2003

To address how serpins might fold so as to adopt the mechanistically required metastable conformation we have compared the predicted secondary structures of the reactive center loops (RCLs) of a large number of serpins with those of the equivalent regions of other non‐serpin protein proteinase inhibitors. Whereas the RCLs of non‐serpin inhibitors are predicted to be loop or β‐strand, those of inhibitory serpins are strongly predicted to be α‐helical. However, non‐inhibitory serpins, which also adopt the metastable conformation, show no consistent preference for α‐helix. We propose that the RCL primary structure plays little role in promoting the metastable serpin conformation. Instead we hypothesize that preference for the metastable state results from the incorporation of part of the RCL into β‐sheet C, which as a consequence precludes incorporation of the RCL into β‐sheet A to give the most stable conformation. Consequently the RCL must be exposed and by default will adopt the most stable conformation in this particular context, which is likely to be an α‐helix irrespective of the primary structure. Thus the observed correlation between inhibitory properties in serpins and prediction of α‐helix in the RCL may instead reflect a need for alanine residues between positions P12 and P9 for functioning as an inhibitor rather than a structural or mechanistic requirement for α‐helix.
Slow troponin C gene expression in chicken heart and liver is regulated by similar enhancers
Authors: Grewal J.S. , Bag J.
Published: April 2003

Two isoforms of troponin C (TnC) are encoded by distinct single copy genes. Expression of fast TnC is restricted to the skeletal muscle, whereas the slow isoform is expressed in both skeletal and cardiac muscle. Chicken slow TnC (cTnC) gene is also expressed in some non‐muscle tissues like the liver and the brain. Expression of cTnC gene is regulated by two distinct enhancers in cardiac and skeletal muscles. The cardiac specific enhancer is located in the immediate 5′ flanking region (bp −124 to −79) of the murine cTnC gene whereas the skeletal enhancer is located within the first intron (bp 997 to 1141). In the present study we have examined how cTnC gene expression is regulated in the chicken liver. Transient transfection of liver cells with cTnC‐CAT reporter constructs containing various regions of the murine cTnC gene showed that its expression in chicken liver is regulated by the cardiac specific enhancer. Furthermore, electrophoretic mobility shift assays using synthetic oligonucleotides corresponding to both CEF‐1 and CEF‐2 regions of the murine cardiac enhancer revealed formation of specific DNA‐protein complexes. Ultraviolet light induced covalent linking of nuclear proteins to CEF‐1 and CEF‐2 oligomers were used to examine the nature of the cardiac enhancer binding polypeptides; one polypeptide of 48 kDa appeared to bind to both CEF‐1 and CEF‐2 sequences.
The masked cysteine residues in methylmalonyl‐CoA mutase from Propionibacterium shermanii are essential for catalytic activity
Authors: Roy Ipsita
Published: April 2003

Two masked cysteine residues have been reported in methylmalonyl‐CoA mutase from Propionibacterium shermanii, Cys‐535 in the α‐subunit and Cys‐517 in the β‐unit, which are revealed only after reduction of the denatured enzyme with dithiothreitol. It has been postulated that these residues are involved in disulphide linkages to unknown thiols of low M

r
. These two masked cysteine residues have been changed to an alanine, individually. Both the mutants, C535αA and C517βA, were inactive. This shows that both these residues are essential for catalytic activity.
Identification and characterization of a lower plant Ypt/Rab guanosine dissociation inhibitor (GDI)
Authors: Beyser Kurt , Fabry Stefan
Published: April 2003

The cDNA encoding a Ypt/Rab guanosine dissociation inhibitor (Ypt‐GDI) was isolated from the multicellular green alga Volvox carteri, representing the first complete plant gdi gene described. The gdiV1 gene occurs as a single copy in the algal genome, indicating that its product regulates all YptV proteins from Volvox. The derived GDI protein (GDIV1p) shows high similarity to animal and fungal GDIs. A specific antibody developed against GDIV1p detected the protein throughout the whole Volvox life‐cycle. GDIV1p was localized in the cytoplasm and in the algal flagellum. This is in line with earlier findings of a dual localization of Ypt proteins both in the cell body and in the motility organelle, and indicates a novel role of the GDI/Ypt system, possibly in intraflagellar transport.
Consumer response to service and product quality: A study of motor vehicle owners
Authors: Archer N.P. , Wesolowsky G.O.
Published: April 2003

There is currently much interest in the idea of integrated quality management for durable products, extending from the product design, development and manufacturing process and through the ownership cycle of the product. We have carried out a logit analysis of events pertaining to a critical incident model which demonstrates how quality in both the product and its supporting services, as well as the interactions between these factors, can affect owner intentions regarding future purchases. The model was evaluated through a study of 659 motor vehicle owners. Two of our specific conclusions are: (1) our data suggests that owners tend to have a tolerance towards negative vehicle incidents, but negative service incidents can harm owner perceptions of both the dealer and the manufacturer, and (2) positive critical incidents can counteract negative critical incidents. Proactively creating positive service incidents and avoiding negative service incidents can help improve customer loyalty to the service agent and counteract negative vehicle incidents which affect loyalty to the manufacturer. We also suggest that the results from this study may be generalizable to service and product quality management for other types of equipment.
Retinal degeneration in primates raised on a synthetic human infant formula
Authors: Sturman John A. , Wen Guang Y. , Wisniewski Henryk M. , Neuringer Martha D.
Published: April 2003

A degeneration of the retinal cone photoreceptor cells, but not of the rod photoreceptor cells, is present in rhesus monkeys raised from birth for 26 months on a commercially available human infant protein hydrolyzate formula. This degeneration is associated with a selective decrease in plasma taurine concentration, and is entirely prevented by supplementing the formula with taurine. A reduced conedominated ERG was present at 10 months, but not at 18 or 26 months. These results suggest that the implications of the reduced taurine concentrations in human infants fed synthetic formulas containing little or no taurine should be reconsidered, since adverse effects on the visual system may only be detectable at the ultrastructural level.
In vivo uptake of heterologous alphafetoprotein and serum albumin by ependymal cells of developing chick embryos
Authors: Moro Ricardo , Fielitz Walter , Esteves Adriana , Grunberg José , Uriel José
Published: April 2003

The in vivo uptake by neuroepithelial cells of rat serum proteins injected into the mesencephalic cavity of developing chicken was demonstrated by immunohistochemical methods. It was found that 48 h after inoculation, rat alphafetoprotein (AFP) and serum albumin (SA) localize in the same places as do chicken AFP and SA. No labelling was present for rat or chicken IgG. We also present evidence showing that chicken ovalbumin, which is not normally found inside ependymal cells is not internalized even when injected into the cerebrospinal fluid at 30‐fold its physiological concentration. The existence of transient specific receptors which could be responsible for this protein uptake is proposed. The possible implications in relation to developmental biology are discussed.
Muscarinic receptor regulation in the sympathetically innervated avian expansor secundariorum
Authors: Rush R. A. , Crouch M. F.
Published: April 2003

We sought to examine further the regulation of muscarinic receptors in the developing expansor secundariorum, a smooth muscle of the avian wing. [3H]Quinuclidinyl benzilate binding was used as a measure of muscarinic receptors present in the muscle, which gradually decline in density from hatch during the following few weeks. Receptor loss can be prevented by denervation of the muscle immediately after hatch, but receptor density is not recovered by denervation in older birds. As the major innervation is provided by sympathetic, noradrenergic fibres with no evidence of a cholinergic input, the action of several pharmacological agents known to affect noradrenergic transmission was examined. Reserpine partially prevented the early receptor decline but phenoxybenzamine and dimethylphenylpiperazinium did not significantly affect receptor density. The muscle was also immobilized by tenotomy, since this unique muscle is attached to the shoulder by a long, discrete tendon. Tenotomy significantly retarded the normal developmental receptor loss. It is suggested that in this muscle, muscarinic receptor density is regulated by noradrenergic nerves, possibly by a mechanism involving the transmitter, noradrenaline.
Viability of locus coeruleus cultures in the fourth ventricle of the adult rat
Authors: Multon M.F. , McRae‐Degueurce A.
Published: April 2003

Both tyrosine hydroxylase and dopamine‐beta‐hydroxylase immunocytochemistry indicated the survival of catecholamine neurons and processes in 7‐day‐old organotype cultures of the locus coeruleus. Cultures of this age were transplanted in the 4th ventricle of adult rats via the cisterna magna. Two months after transplantation microscopic observations revealed that the transplant developed with a defined neural organization. Following tyrosine hydroxylase immunocytochemistry, immunoreactive cells were identified within the transplants. These results indicate that organotype cultures of the locus coeruleus survive within the 4th ventricle of adult rats.
Cerebellar DNA and tissue water changes in the brain of diabetes insipidus brattleboro rats are already present at birth
Authors: Boer G.J. , Dozy M.H. , Uylings H.B.M.
Published: April 2003

Homozygous (HOM) Brattleboro rat newborns, congenitally lacking vasopressin, weighed less than heterozygous controls born from HOM females and reared as 9‐pup litters. Whole brain and specific brain regions (cerebral cortex, medulla oblongata and colliculi but not the cerebellum) were also reduced in weight. Decreased tissue water content was observed in the regions affected in weight. In the cerebellum, on the other hand, a 20% lower DNA content was measured, which points to a prenatal origin for the impaired cerebellar neurogenesis which is known to exist postnatally.
Dopamine‐β‐hydroxylase‐like immunoreactivity in the fetal cerebral cortex of the rat: Noradrenergic ascending pathways and terminal fields
Authors: Verney Catherine , Berger Brigitte , Baulac Michel , Helle Karen B. , Alvarez Chantal
Published: April 2003

A topographical analysis of the noradrenergic innervation in the fetal rat cerebral cortex was carried out from embryonic day 15 (E15) until birth using antibodies raised against dopamine‐β‐hydroxylase (DBH). During late gestation DBH‐like immunoreactive axons were coursing through the basal forebrain along three pathways: (1) a medial component reached the medial cortex and then ran caudally along the anlage of the cingulum bundle; (2) a lateral component reached the frontal pole and curved ventro‐dorsally in the primordium of the external capsule; (3) a few fibers were observed along the ventral amygdaloid bundle toward the amygdaloid complex and the surrounding cortex. No DBH positive fibers were observed in the main body of the internal capsule.

The first noradrenergic axons were seen at E17 in the frontal pole, the lateral frontal cortex, and in the medial frontal cortex which also receives a dopaminergic input. The innervation then extended caudally, but the dorsal part of the cortex was reached after a 2‐day delay when compared to the medial and lateral parts. The arrival of noradrenergic axons did not parallel the gradient of cortical neurogenesis; however, all cortical areas were innervated at birth. DBH positive fibers reached a given cortical region simultaneously through the marginal and intermediate zones and then invaded the cortical plate.
The ontogenesis of the dopaminergic cell in the pre‐ and postnatal guinea pig retina
Authors: Parkinson David , Spira Arthur , Wyse J. Patrick , Patten Marilyn
Published: April 2003

We have examined the development of the dopaminergic system of the guinea pig retina, a species in which retinal neuronal and synaptic differentiation occurs largely in utero. Fetal animals aged 42–69 days (full term), neonates, postnatal (pn) animals to 12 weeks, and mature animals were studied to determine retinal dopamine (DA) storage, metabolism (DOPAC), in vitro tyrosine hydroxylase (TH) activity, postsynaptic target activation (cAMP stimulation) and localization (formaldehyde‐induced histofluorescence). DA‐stimulated adenylate cyclase at 42 days of gestation was threefold over basal activity, preceding the onset of the accumulation of DA and DOPAC at 45 days, and the initial localization of DA in cell perikarya at 47 days and in processes at 50 days. At birth DA and DOPAC levels were 45 and 37%, respectively, of adult levels. DA levels remained stable during the first few days pn, although in vitro TH activity was capable of stimulation by light in the neonate as in the mature animal. DA and TH activity increased from 1 week pn to reach adult levels by 10 weeks pn. Although a significant degree of development of the dopaminergic neurotransmitter system in the guinea pig occurs before birth the attainment of a fully mature system postnatally may require normal photic stimulation of physiologic activity.
Postnatal development of calmodulin and calmodulin‐dependent phosphodiesterase in different regions of the rat central nervous system
Authors: Toro M.J. , Salinas‐Fando M. , Montoya E.
Published: April 2003

We have studied the concentration of calmodulin and phosphodiesterase (cAMP high Km) in five different parts of the rat central nervous system (hemispheres, cerebellum, diencephalon, brain stem and spinal cord) during postnatal development (5, 10, 15, 20, 30 and 45 days after birth). The concentration of the enzyme and its regulatory protein were independent, so that no correlation could be established between them. In most structures, calmodulin concentration tended to decrease with age, while phosphodiesterase increased or remained at similar values during the time studied.

The calmodulin inhibitor trifluoperazine, inhibited phosphodiesterase activity to different degrees, depending on the structure, and age. Hemispheres, diencephalon and brain stem showed maximal inhibition (approximately 95‐65% of control). In these structures, inhibition was higher in older animals. By contrast, cerebellum and spinal cord PDE was less inhibited by trifluoperazine (65‐50% of control), and inhibition was independent of age. The validation of a method for both calmodulin and phosphodiesterase assay, using a modification of established methods, is also reported.
Oxidative metabolism in cultured astroglial cells from rat brain
Authors: Peterson Anders , Odland Lena , Sensenbrenner Moniqiue , Walum Erik
Published: April 2003

Cirowth, morphology, glutamine synthetase activity, eytoehrome C oxidase activity and respiratory activity of rat brain cultures enriched in astrocytes were studied during four weeks in culture. Two different polarographic methods were used for measurement of respiratory activity: one newly developed perfusion method leaving the cellular monolayer morphologically intact and still attached to the culture dish, and one traditional stirring method involving the removal of cells from the culture vessel. Regardless of the method used, a stable respiratory activity was registrated throughout the four weeks of culturing. Also the eytoehrome C oxidase activity remained unchanged. In perfusion all absolute values for respiration were found to be higher than those obtained with the stirring method. The use of the stirring technique resulted in a doubling of oxygen consumption upon succinate addition. No such effect was seen in perfusion. It can thus be concluded that the removal of cultured astrocytic cells from their substratum alters their respiratory activity and their response to added substrates.
Transient expression of 5‐HT1A receptor binding sites in some areas of the rat CNS during postnatal development
Authors: Daval G. , Vergé D. , Becerril A. , Gozlan H. , Spampinato U. , Hamon M.
Published: April 2003

The developmental evolution of 5‐HT1A receptor binding sites was examined in the rat CNS during the early postnatal period using quantitative autoradiography and binding assays with 3H‐8‐OH‐DPAT as the selective ligand. A progressive increase in the density of 5‐HT1A sites was observed in the hippocampus, septum and cerebral cortex, up to adult levels which were reached around the third postnatal week. In contrast, complex biphasic (increase then decrease) changes were noted in other structures (for instance the nucleus of the lateral lemniscus) and even a progressive decrease in the density of 5‐HT1A sites took place in the cerebellum during the first two postnatal weeks. The transient expression of 5‐HT1A receptor binding sites in a structure such as the cerebellum which develops exclusively for the postnatal period further supports that 5‐HT might play a trophic role during maturation of the CNS.
Messenger RNAs of β‐amyloid precursor protein and prion protein are regulated by nerve growth factor in PC12 cells
Authors: Wion Didier , Le Bert Marc , Brachet Philippe
Published: April 2003

The effect of the neurotrophic factor NGF on the expression of two genes involved in the accumulation of amyloid deposits in neurodegenerative disorders was studied in a clonal cell line, PC12. Use of hybridization methods showed that NGF increased the cellular pool of the mRNA of the prion protein, a macromolecule known to generate fibrillary aggregates in the brain of scrapie‐infected animals. Maximal levels of prion mRNA were obtained after 7 days of treatment, but a significant increase was already detectable after 48 hr of exposure to NGF. In contrast, the factor did not increase the cellular content of the transcripts coding for the precursor of the β‐amyloid peptide (APP), which participates in the formation of neuritic plaques in human brains affected by Alzheimer's disease. However, NGF caused a drop in the molecular weight of that mRNA. This change, which is likely to result from a loss of 100–200 bp, was already detected after 24 hr of treatment. These results indicate that NGF induces in target neuronal cells a quantitative and a qualitative modification of the transcription products encoding two different amyloid precursor proteins.
Development of postsynaptic‐like specializations of the neuromuscular synapse in the absence of motor nerve
Authors: Sohal G. S.
Published: April 2003

It was previously reported that the acetylcholine receptor clusters and acetylcholinesterase appear on embryonic superior oblique muscle cells developing in vivo without motor nerve contacts. The objective of this study was to examine whether some other components of neuromuscular junction also form on muscle cells developing in vivo in the absence of motor neurons. In the present study, postsynaptic specializations such as junctional folds, postsynaptic density and basal lamina were studied in normal and aneural muscles. The superior oblique muscle of duck embryos was made aneural by permanent destruction of trochlear motor neurons by cauterizing midbrain on embryonic day 7; 3 days before the motor neurons normally project their axons into the muscle. Normal and aneural muscles from embryonic days 10 to 25 were processed for electron microscopy. The results indicate that morphological specializations such as junction‐like folds, postsynaptic‐like density, and basal lamina also develop in the absence of motor neuron contacts. Whether the differentiation of specialized synaptic basal lamina is dependent on the presence of motor neurons was examined by utilizing a monoclonal antibody against heparan sulfate proteoglycan. Immunohistochemical studies indicate that specialized synaptic basal lamina differentiates in the absence of motor neurons. Thus, the mechanism of development of postsynaptic components of neuromuscular junction in this muscle is not dependent on motor neuron contacts. These results also suggest that the postsynaptic cell plays a more active role in synapse formation than previously realized. The results are discussed in relation to the control of synapse numbers by the postsynaptic cell.
Survival and neuritic growth of sympathoadrenal (chromaffin) precursor cells in vitro
Authors: Seidl K. , Unsicker K.
Published: April 2003

Chromaffin precursor cells from embryonic rat adrenal glands were isolated at 16.3 and 20.3 days of gestation and purified by centrifugation on density gradients. Approximately 50% of the cells of both age groups that had attached to the culture substratum by 12 hr survived during a 4‐day culture period in the absence of exogenous trophic factors. Nerve growth factor (NGF) and a C6 glioma‐cell‐conditioned medium (C6‐CM) had no or a very moderate promoting effect on survival. The gluco‐corticoid dexamethasone (DEX) supported the survival of 70–80% of the cells that otherwise would have died. Spontaneous neuritic growth of the sympathoadrenal precursor cells was significantly more pronounced with cells isolated at embryonic day (E) 16.3 than at E20.3. NGF had a significantly smaller promoting effect on neurite ougrowth at E16.3 than at E20.3. C6‐CM induced neurite outgrowth from 25% (E16.3) and 35% (E20.3) of the surviving cells. DEX (10−6 M) completely abolished spontaneous neuritic growth and partially suppressed C6‐CM‐mediated fiber outgrowth. These data underscore the importance of glucocorticoids for the maintenance and development of an endocrine morphologic phenotype of sympathoadrenal precursors. They suggest that the cells may be initially driven by growth factors other than NGF into a neuronal direction and that they lack NGF‐responsiveness and dependence during the early stages of their development.
Developmental changes in 5‐hydroxytryptamine immunoreactivity of sympathetic cells
Authors: Soinila Seppo , Ahonen Marketta , Lahtinen Tuija , Häppölä Olli
Published: April 2003

5‐Hydroxytryptamine was demonstrated immunohistochemically in developing sympathetic chain ganglia, adrenal medullae and retroperitoneal paraganglionic tissue. Initially, all catecholamine‐synthesizing cells were immunoreactive to 5‐hydroxytryptamine, but during the maturation some sympathetic cell types lose this property. In the ganglia, small intensely fluorescent cells retain their 5‐hydroxytryptamine content throughout maturation. This property is expressed transitionally in some neonatal principal neurons, but can be triggered even in adult neurons, e.g. after loading with l‐tryptophan. In the adrenal medulla, immunoreactivity to 5‐hydroxytryptamine is carried over to the adrenaline‐synthesizing cells, while in the main retroperitoneal paraganglion it is observed in both adrenaline and noradrenaline cells. These results suggest that initial expression of 5‐hydroxytryptamine immunoreactivity is coupled to the onset of catecholamine synthesis, but is regulated differently in each mature sympathetic organ.
NGF primed spleen cells injected in brain of developing rats differentiate into mast cells
Authors: Aloe Luigi , De Simone Roberta
Published: April 2003

The aim of this work was to study the topographic distribution and the morphological behaviour of nerve growth factor (NGF) primed spleen cells injected into the lateral ventricles of developing rat brain. Serial coronal brain sections showed that these transplanted cells acquire phenotypical characteristics similar to those of mast cells (MCs) and that they enhance local neovascularization. These results, together with the observation that these cells are located in proximity to the hippocampus, a brain tissue which contains one of the highest levels of NGF, provide a model for studying the relationship between NGF and MC differentiation and secretion.
Non‐selective afferent innervation develops in embryonic mouse spinal cord‐dorsal root ganglia explants chronically exposed to GM1 ganglioside
Authors: Baker Robert E. , Janzen Daan Gaasbeek
Published: April 2003

Projection patterns of dorsal root ganglion afferents within organotypic expiants of fetal mouse spinal cord were examined histologically using a horseradish peroxidase staining method. All expiants were also examined electrophysiologically and showed spontaneous and evoked bioelectric discharges, which were evenly distributed across the cord explants. Explants chronically grown in a serum‐free medium containing the monosialoganglioside GM1 failed to develop dorsal cord selectivity as was previously observed when a mixture of gangliosides was used. It therefore appears that not all gangliosides can induce selectivity in this model.