bluuebunny/crossref_metadata_2025_split huggingface dataset:
Focal adhesion proteins associated with apical stress fibers of human fibroblasts
Authors: Katoh Kazuo , Masuda Michitaka , Kano Yumiko , Fujiwara Keigi , Jinguji Yoichi 
Published: February 2005

AbstractHuman fibroblasts stained with fluorescently labeled phalloidin revealed many stress fibers within the apical cytoplasm in addition to those located along the basal plasma membrane and associated with focal adhesions. The staining patterns of these apical stress fibers with fluorescent phalloidin, anti‐α‐actinin, and anti‐myosin were identical to those of the basal stress fibers, suggesting the same macromolecular organization for both types f stress fibers. There were two types of apical stress fibers that clearly interacted with the apical plasma membrane, those extending between the basal and the apical plasma membrane and those having both ends on the basal membrane forming arches whose top interacted with the apical plasma membrane. By electron microscopy, we observed that apical stress fibers were associated with the apical plasma membrane via electron‐dense plaques reminiscent of the focal adhesion. Since several proteins have been specifically localized to the focal adhesion site, we examined whether they were also present at the apical stress fiber‐membrane association site by using immunocy‐tochemical methods and image reconstruction techniques. We found that vinculin, talin, paxillin, a fibronectin receptor protein, several integrin subunits including β1, fibronectin, and proteins with phosphorylated tyrosine were also components of the apical plaque. These observations indicate that apical stress fibers are attached to the plasma membrane by using principally the same molecular assembly as the focal adhesion associated with the basal stress fiber. We suggest that the complex molecular organization of the focal adhesion is not demanded by cell adhesion, but rather it is needed for anchoring stress fibers to the plasma membrane. Apical plaques did not stain with the anti‐integrin αv subunit or anti‐focal adhesion associated kinase (FAK), although these antibodies stained focal adhesions. These results suggest that the apical stress fiber‐membrane contact has some important functions different from those of the focal adhesion.
Fascins, a family of actin bundling proteins
Authors: Edwards Robert A. , Bryan Joseph 
Published: February 2005

AbstractFascin is an actin‐bundling protein that was first isolated from cytoplasmic extracts of sea urchin eggs [Kane, 1975: J. Cell Biol. 66:305–315] and was the first bundling protein to be charactrized in vitro. Subsequent work has shown that fascin bundles actin filaments in fertilized egg microvilli and filopodia of phagocytic coelomocytes [Otto et al., 1980: Cell Motil. 1:31–40; Otto and Bryan, 1981: Cell Motil. 1:179–192]. Fifteen years later, the molecular cloning of sea urchin fascin [Bryan et al., 1993: Proc. Natl. Acad. Sci. U.S.A. 90:9115–9119] has led to the identification and characterization of homologous proteins in Drosophila [Cant et al., 1994: J. Cell Biol. 125:369–380], Xenopus [Holthuis et al., 1994: Biochim. Biophys. Acta. 1219:184–188], rodents [Edwards et al., 1995: J. Biol. Chem. 270:10764–10770], and humans [Duh et al., 1994: DNA Cell Biol. 13:821–827; Mosialos et al., 1994: J. Virol. 68:7320–7328] that bundle actin filaments into structures which stabilize cellular processes ranging from mechanosensory bristles to the filopodia of nerve growth cones. Fascin has emerged from relative obscurity as an exotic invertebrate egg protein to being recognized as a widely expressed protein found in a broad spectrum of tissues and organisms. This purpose of this review is to relate the early studies done on sea urchin and HeLa cell fascins to the recent molecular biology that defines a family of bundling proteins, and discuss the current state of knowledge regarding fascin structure and function. © 1995 Wiley‐Liss, Inc.
Centrin in the photoreceptor cells of mammalian retinae
Authors: Wolfrum Uwe 
Published: February 2005

AbstractPhotoreceptor cells of vertebrate retinae are highly specialized ciliary cells. Their non‐motile ciliated structure is restricted to the so‐called connecting cilium at the joint between the light sensitive outer segment and the metabolically active inner segment. Extensive bidirectional intracellular transport between both segments is forced to occur through this tight connecting cilium. In the present study it is shown that the Ca2+‐binding, phospho‐protein centrin is present in mammalian retinae. Western blot and immunoprecipitation experiments reveal that anti‐centrin antibodies react with purified photoreceptor cell fractions of retinae in bands at a molecular weight of 20 kDa, the molecular weight of centrins found in other cells. Indirect immunofluorescence analysis of cryosections through retinae of different mammalian species show that centrin is present only in centrosomes and basal bodies but also more extensively at the linkage between the inner and the outer segment of the photoreceptor cells. Immunocytological studies on isolated rod cells and immunoelectron microscopy clearly demonstrate a unique presence of centrin in the connecting cilium of photoreceptor cells. High molecular identity between centrins in lower eukaryotes and mammals indicates that centrin may play a role in cellular motility and/or in microtubule severing in the mammalian retina. © 1995 Wiley‐Liss, Inc.
Dynein family of motor proteins: Present status and future questions
Authors: Gibbons I. R. 
Published: February 2005

AbstractAnalysis of sequence relationships in dynein heavy chains shows that dynein motor proteins comprise a single homologous family with three main branches, cytoplasmic dynein, axonemal dynein, and a third branch represented by DYH1B that lies between the other two. In all branches of the family the dynein heavy chain has four copies of the P‐loop motif for a nucleotide‐binding site spaced ∼300 residues apart in its midregion, with the amino acid sequence GPAGTGKT in the P‐loop of the hydrolytic ATP‐binding site. Cytoplasmic dyneins appear more primitive in that the heavy chain usually occurs as a homodimer, with traces of the early evolution of its four P‐loop motifs by gene duplication being recognizable. In the axonemal subfamily the heavy chains occur as heterodimers or heterotrimers encoded by multiple genes, and their non‐hydrolytic P‐loop motifs are much more divergent with little trace of their origin by gene duplication. The DYH1B subfamily is more closely related to the cytoplasmic dyneins in sequence, but appears related to axonemal dyneins in function since it becomes upregulated during reciliation and has not been found in organisms, such as yeast and Dictyostelium, that are totally without cilia or flagella.
Computer simulation of nerve growth cone filopodial dynamics for visualization and analysis
Authors: Buettner Helen M. 
Published: February 2005

AbstractThe neuronal growth cone plays a fundamental role in nerve development and regeneration. A sensory‐motile structure, it determines the path of axonal extension through its interactions with the extracellular environment, ultimately directing the formation of functional connections in the nervous system. Though several mechanisms of interaction have been proposed, these have been difficult to describe quantitatively due to the complexity of growth cone behavior, as manifested in the randomly and rapidly changing shape of the growth cone. The application of mathematical techniques to model growth cone shape and motility in terms of underlying processes represents a promising approach with untapped potential for helping to unravel this complexity while revealing new insights into axonal pathfinding events. This paper presents a simulation model for filopodial dynamics, a primary feature of the motile growth cone. The model produces realizations of dynamic filopodial structure on representative growth cones for a given set of model parameters, which include the rates of filopodial initiation, extension, and retraction, filopodial length at maximum extension, and angular orientation. These parameters are based on recent experimental characterization of filopodial dynamics [Buettner et al., 1994: Dev. Biol. 163:407–422]. The mathematical relationship between the model parameters and average filopodial number and length per growth cone is described, and the contribution of individual parameters to overall filopodial morphology is illustrated both visually and numerically. In addition, the model is used to simulate filopodial encounter with a target for various conditions of filopodial dynamics. The result is characterized in terms of a mean encounter time for a population of growth cones and provides an indication of the effect of individual parameters of filopodial dynamics on the encounter process. Future experimental testing will be required to develop the model further. However, in its current form, the model enables a first approximation analysis of many hypotheses of growth cone migration and pathfinding and offers insight into the the underlying mechanismes of nerve growth and regeneration. © 1995 Wiley‐Liss, Inc.
Plakoglobin: Kinetics of synthesis, phosphorylation, stability, and interactions with desmoglein and E‐cadherin
Authors: Pasdar Manijeh , Li Zhi , Chlumecky Vera 
Published: February 2005

AbstractWe have analyzed the kinetics of synthesis, phosphorylation, and stability of the soluble and insoluble plakoglobin (PG) and their interactions with Dsg1 and E‐cadherin in Madin‐Darby canine kidney (MDCK) epithelial cells in the absence of cell adhesion and after the induction of cell‐cell contact. Using a combination of biochemical and morphological approaches, we show that newly synthesized PG enters a soluble:insoluble pool of proteins in a 60:40 ratio regardles of cell‐cell contact. Following synthesis, PG is increasingly found in the insoluble pool. Although cell‐cell contact does not effect either the size of each pool or the rate or efficiency of the transfer from the soluble into the insoluble pool, it results in a significant increase in the metabolic stability of the newly synthesized insoluble PG. The soluble PG initially forms separate complexes with E‐cadherin and Dsg1. PG‐Dsg1 complexes become insoluble and localize to the desmosome. PG‐E‐cadherin complexes remain soluble and are distributed intracellularly. The insoluble PG and E‐cadherin detected at the cell periphery remain distinctly separate, as demonstrated previously [Hinck et al., 1994:J. Cell Biol.125:1327–1340; Nathke et al., 1994:J. Cell Biol.125:1341–1352]. In addition, we detected a separate pool of PG which is not associated with either Dsg1 or E‐cadherin and after the induction of cell‐cell contact becomes primarily insoluble and is distributed along the lateral membrane. Phoshorylation analysis showed that there is a significantly greater amount of phosphorylated PG in the soluble pool than in the insoluble pool. In addition the soluble pool is both serine and theronine phosphorylated, whereas the insoluble PG is primarily phosphorylated on serine residues. © 1995 Wiley‐Liss, Inc.
Melting behavior and growth of colquiriite laser crystals
Authors: Klimm D. , Uecker R. , Reiche P. 
Published: February 2005

AbstractColquiriite‐type crystals like LiCaAlF6, LiSrAlF6, LiCaGaF6, and LiSrGaF6 are interesting host crystals for Cr3+ or Ce3+ laser ion doping. Although the Ca compounds show interesting optical properties, the growth of these crystals is difficult due to incongruent melting. LiCaGaF6 crystallizes with CaF2 deficiency and melts incongruently at 710–720 °C. Hydrolysis with traces of moisture is critical for all fluorides. AlF3 and GaF3 have the highest sensitivity among the main components of the colquiriites. Hydrolysis can only be slightly suppressed by hydrogen fluoride. Elementary fluorine or reactive gases as carbon tetrafluoride are more effective by several orders of magnitude. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray photoelectron spectroscopy investigations of Y3Al5O12:Yb single crystal
Authors: Kruczek M. , Talik E. , Sakowska H. , Gała M. , Świrkowicz M. 
Published: February 2005

AbstractX‐ray photoelectron spectroscopy was used to study the chemical composition and electronic structure of the Y3Al5O12:Yb (YAG:Yb) crystals. The contamination of the crystal with carbon and oxygen in the broken under UHV sample was found. The dopant concentration of Yb, in the mixed valence state, was determined as 12 %. The aluminium concentration is lower than a nominal value. The chemical shift analysis shows more ionic bond of Y‐O than Al‐O. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman and Rayleigh scattering study of crystalline polyoxyethyleneglycols
Authors: Kozielski M. , Mühle M. , Błaszczak Z. , Szybowicz M. 
Published: February 2005

AbstractResults of the study of Raman and Rayleigh scattering in crystalline polyoxyethyleneglycols (PEG) and PEG 1500 aqueous solution are reported. The conformational changes of the polymer chain have been studied as a function of PEG water solution concentration and molecular weight. Intensity ratios of the gauche and trans conformation around C–C and C–O bonds have been estimated from the Raman spectra. Moreover, from the Raman band parameters the values of the order parameters versus aqueous solution concentration have been determined. The influence of an external electric field on these parameters has been analysed. Mutual orientation of polyoxyethyleneglycol chains in the crystalline and liquid state has been studied on the basis of the angular correlation parameters obtained from the Rayleigh band intensity as a function of aqueous solution concentration and molecular weight. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical studies of defects generated in neutron‐irradiated Cz‐Si during HP‐HT treatment
Authors: Surma B. , Misiuk A. , Wnuk A. , Londos C. A. , Bukowski A. 
Published: February 2005

AbstractNeutron‐irradiated Czochralski grown silicon subjected to heat treatment (HT) at 350 °C and 1000 °C under enhanced hydrostatic pressure (HP) was studied in this work. It has been shown that external hydrostatic pressure enhances the creation of VO2 defects in neutron irradiated silicon subjected to the HP ‐ HT treatment at 350 °C. Enhanced formation of platelet‐like oxygen precipitates was found in the samples treated at 1000 °C under 1.1 GPa. This effect was more pronounced in the samples with VO2 defects. Presented results seem to suggest that probably HP helps to transform VO2 to some kind of defects or change alone VO2 defects in the form that can act as an additional nucleus for an additional oxygen precipitation at 1000°C. No correlation between the plate‐like oxygen precipitates related absorption at 1225 cm‐1 and dislocation‐related emission has been confirmed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of InP layers prepared with the addition of Ce, Tm and Lu in the growth melt
Authors: Zavadil J. , Prochazkova O. , Gladkov P. S. 
Published: February 2005

AbstractInP single crystals were grown by liquid phase epitaxy on semi‐insulating InP:Fe and n‐type InP:Sn substrates with cerium, thulium and lutetium additions to the growth melt. Grown layers were examined by low‐temperature photoluminescence spectroscopy and C‐V measurements. Layers prepared with the addition of Ce and Tm exhibit the change of electrical conductivity from n to p, while those grown with Lu admixture remain n‐type. Ce has been found to be incorporated into the InP lattice and sharp luminescence arising from 2F7/2 → 2F5/2 inner shell transitions of Ce3+ at 3600 nm was detected. The highest purifying effect due to RE addition has been found for Tm admixture, where the impurity concentration was decreased by three orders of magnitude and fine spectral features were revealed by photoluminescence spectroscopy. The addition of Tm into the growth melt enables to prepare thick and pure InP layers of p‐type conductivity – a material promising in the context of semiconductor radiation detectors. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinetic Study of Ni2+ and Co2+ Complexation by PADA in AOT‐Based Water‐in‐Oil Microemulsions
Authors: Fernández Esperanza , García‐Río Luis , Knörl Astrid , Leis José Ramón 
Published: February 2005

AbstractA kinetic study was carried out into the complexation of Ni2+ and Co2+ with the bidentate ligand pyridine‐2‐azo‐p′‐(N,N‐dimethylaniline) (PADA) in AOT/isooctane/water microemulsions [where AOT = sodium bis(2‐ethylhexyl)sulfosuccinate]. The results obtained show that the macroscopic rate constants for the formation of the Ni2+‐PADA and Co2+‐PADA complexes decrease as the surfactant concentration and the water content of the system increase. The rate constants are in all cases greater than those observed in an aqueous medium, with catalytic effects of up to 25 times. To interpret the kinetic results a model has been proposed which considers the distribution of PADA between the continuous medium and the interface of the microemulsion, and the distribution of the Nitest 2+ test2+ and the Co2+ cations between the aqueous microdroplet and the interface. The formation and dissociation reactions of the complexes take place only at the interface. On the basis of the model we obtained values for the rate constants for the formation, ki1, and decomposition, ki–1, of the complexes for various values of W (W = [H2O]/[AOT]). The results show that ki–1 is independent of the composition of the microemulsion and that ki1 increases as W decreases. The results also show that the rate constants for the formation of the Co2+‐PADA complex are approximately 50 times greater than those of the Ni2+‐PADA complex. These results are compatible with the fact that the reaction follows an Eigen–Wilkins‐type mechanism and that, in the presence of added salt, there is an increase in the rate constant of water exchange as the saline content of the microdroplet increases, that is, as W decreases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Direct Halogenation of Alcohols and Their Derivatives with tert‐Butyl Halides in the Ionic Liquid [pmIm]Br under Sonication Conditions – A Novel, Efficient and Green Methodology
Authors: Ranu Brindaban C. , Jana Ranjan 
Published: February 2005

AbstractA novel halogenating reagent system for direct halogenation of alcohols has been developed. tert‐Butyl bromide, chloride and iodide in combination with the ionic liquid [pmIm]Br have been found to convert alcohols into the corresponding bromides, chlorides and iodides under sonication conditions (or heating) in good yields. Although a variety of primary and secondary alcohols participated in this reaction without any difficulty, tertiary alcohols remained inert. Several alcohol derivatives such as OTMS, OTBDMS, OAc, OTS and OTHP are also transformed into the corresponding halides in one‐pot fashion by this procedure. A plausible rationale for this transformation is also presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Total Synthesis of 3‐Hydroxydrimanes Mediated by Titanocene(III) – Evaluation of Their Antifeedant Activity
Authors: Justicia José , Oltra J. Enrique , Barrero Alejandro F. , Guadaño Ana , González‐Coloma Azucena , Cuerva Juan M. 
Published: February 2005

AbstractWe describe the first synthesis of 3β‐hydroxydihydroconfertifolin (3) and 3β‐hydroxycinnamolide (4), together with improved procedures for the preparation of other 3‐hydroxydrimanes (2 and 5) scarce in nature. The key step was the titanocene(III)‐promoted cyclization of epoxypolyprenes, readily prepared from commercial polyenes. In this way, we confirm the viability of our procedure for the synthesis of drimane sesquiterpenoids with different functionalization patterns. We also report on the antifeedant activity of 2–5 against four insect species with different feeding ecologies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Asymmetric Synthesis of Isoquinoline Derivatives from Amino Acids
Authors: Sieck Oxana , Ehwald Max , Liebscher Jürgen 
Published: February 2005

AbstractReaction of isoquinolines 1 with N‐arylsulfonylamino acid fluorides 2 provides a highly stereoselective access to new dihydroimidazo[2,1‐a]isoquinolin‐3‐ones 5 via intermediate N‐acylisoquinolinium salts 3. Addition reactions to the en‐amine double bond, such as hydrogenation or epoxidation with dimethyldioxirane, leads to tetrahydroimidazo[2,1‐a]isoquinoline‐3‐ones 6, 7 and oxiranes 8, respectively. Opening of the oxirane ring of the 8 with nucleophiles allows the synthesis of hydroxytetrahydroimidazo[2,1‐a]isoquinolin‐3‐ones 10 or 12 or of the polycyclic 1,4‐dioxane 13 in high stereoselectivity. The regioselectivity of the oxiran ring opening depends on the kind of nucleophile and the conditions. Reaction of dihydroisoquinoline with O‐TBDMS‐mandelic acid chloride 15 leads to a tetrahydrooxazolo[2,3‐a]isoquinoline 17 with opposite facial selectivity as compared with dihydroimidazo[2,1‐a]isoquinolin‐3‐ones 5. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Be(II) Graphite Coated Membrane Sensor Based on a Recently Synthesized Benzo‐9‐Crown‐3 Derivative
Authors: Ganjali Mohammad Reza , Akbar Vahideh , Norouzi Parviz , Moghimi Abolghasem , Sepehrifard Ali 
Published: February 2005

AbstractA highly sensitive and selective membrane electrode with 9‐crown‐3 derivative (CD) as ionophore, potassium tetrakis‐(p‐chlorophenyl) borate as anionic additive (KTB), acetophenone (AP) as solvent mediator was prepared and investigated as a Be(II) sensor. The best performance was observed with the membrane having the percent ratio 30% PVC: 8% CD: 6% KTB: 56% Acetophenone. The poly(vinyl chloride) PVC membrane containing 9‐crown‐3 derivative (CD) directly coated on a graphite electrode, shows a Nernstian response for Be(II) ions over a very wide concentration range (1.0×10−1−1.0×10−7 M) with a detection limit of 8.0×10−8 M (ca. 0.72 ng/mL). It has a fast response time of ca. 20 s and can be used for at least 10 weeks without any major deviation in potential. The proposed sensor exhibits very good selectivity with respect to common alkali, alkaline earth, transition and heavy metal ions. The proposed sensor was used as end point indicator electrode in the titration of Be(II) ions with EDTA. It was also applied to determination of Be(II) in real sample.
An Electrochemical Biosensor with Cholesterol Oxidase/ Sol‐Gel Film on a Nanoplatinum/Carbon Nanotube Electrode
Authors: Qiaocui Shi , Tuzhi Peng , Yunu Zhu , Yang Catherine F. 
Published: February 2005

AbstractThe carbon nanotubes decorated nanoplatinum (CNT‐Pt) were prepared using a chemical reduction method and a novel base electrode was constructed by intercalating CNT‐Pt on the surface of a waxed graphite electrode. The results showed that the nano‐particles of platinum at a waxed graphite electrode exhibits high catalytic activity for the reduction of hydrogen peroxide. The cholesterol oxidase (ChOx), chosen as a model enzyme, was immobilized with sol‐gel on the CNT‐Pt base electrode to construct a biosensor. The current response of the biosensor for cholesterol was very rapid (<20 s). The linear range for cholesterol measurement was 4.0×10−6 mol/L −1.0×10−4 mol/L with a detection limit of 1.4×10−6 mol/L. The experiments also showed that the ChOx/sol‐gel/CNT‐Pt biosensor was sensitive and stable in detecting cholesterol in serum samples.