bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rat Muscle Fructose-1,6-Bisphosphatase: Cloning of the cDNA, Expression of the Recombinant Enzyme, and Expression Analysis in Different Tissues
Authors: Al-Robaiy Samiya , Eschrich Klaus 
Published: October 2004

AbstractThe 1282 bp cDNA of an isoenzyme of fructose-1,6- bisphosphatase was cloned from rat muscle. It shows 70% positional identity to the cDNA of rat liver fructose- 1,6-bisphosphatase and is clearly the product of a gene different from that coding for the liver enzyme. After cloning of the coding region of the rat muscle fructose-1,6-bisphosphatase cDNA in an expression vector, the recombinant enzyme could be detected inE. colicell-free extracts by activity determination and Western blotting. Overexpressed fructose-1,6-bisphosphatase was found to be allosterically inhibited by AMP comparably to the enzyme isolated from rat muscle. Analysis of steady-state mRNA levels of various rat tissues with reverse-transcriptase polymerase chain reaction (RT-PCR) and Northern blotting revealed one or the two fructose-1,6-bisphosphatase isoenzyme mRNAs in most tissues tested with significant quantitative differences. Quantitative PCR using a homologous competitor showed that 1 μg of total RNA of rat muscle contains 1.7 × 106molecules of rat muscle fructose-1,6-bisphosphatase mRNA. 3 × 104copies of this message were found per μg total RNA of heart and kidney, respectively.
Fluorometric Microassays for the Determination of Cathepsin L and Cathepsin S Activities in Tissue Extracts
Authors: Werle Bernd , Staib Alexander , Jülke Britta , Ebert Werner , Zladoidsky Pavel , Sekirnik Andreja , Kos Janko , Spiess Eberhard 
Published: October 2004

AbstractWe established a continuous semi-microassay, and for large-scale studies both a stopped and a continuous microtiter plate assay for the fluorometric determination of cathepsin L and cathepsin S activities in body fluids, tissues or cell extracts in the presence of cathepsin B. For the detection of enzymatic activities we used the synthetic substrate Z-Phe-Arg-AMC, and for discrimination between cathepsin L, S and cathepsin B the specific inhibitor CA-074 for blocking interfering cathepsin B activities was applied. Furthermore, we took advantage of the stability of cathepsin S at pH 7.5 for further differentiation between cathepsin L and cathepsin S activities. The kinetic assays were characterized in terms of imprecision, analytical sensitivity, accuracy and substrate concentration. The within-run coefficients of variation were found to be 4.9%–7.2% for the continuous semi-microassay, 10.3%–11.7% for the stopped, and 4.5%–11.8% for the continuous microtiter plate assay. The between-days coefficients of variation for the continuous semimicroassay were 8.1%–8.9%, while for the stopped and continuous microtiter plate assays the coefficients were 11.2%–13.5% and 5.8%–12.2%, respectively. Compared to the continuous semi-microassay, the stopped and the continuous microtiter plate assays showed 3-fold and 11-fold higher sensitivity, respectively. Comparison between the continuous enzyme activity assays at substrate concentrations of 40 μM and 200μM demonstrated a significant correlation of r = 0.97 and r = 0.99, respectively.The newly developed microtiter plate assay will allow efficient, sensitive and high precision determination of cathepsin L and cathepsin S activities in large-scale studies of cysteine-cathepsin dependent diseases.
Molecular Characterization of a Novel Mammalian DnaJ-Like Sec63p Homolog
Authors: Skowronek Markus H. , Rotter Max , Haas Ingrid G. 
Published: October 2004

AbstractWe identified a human cDNA sequence encoding a polypeptide of 760 amino acids that shares 53% homology and 25.6% identity with the yeast DnaJ-like endoplasmic reticulum (ER) translocon component Sec63p. Three epitope-specific antisera revealed a protein of an apparent molecular mass of 83 kDa, both in human cell extracts and in dog pancreatic microsomes. Biochemical analyses show that it is an integral membrane protein of the rough ER, which has the DnaJ domain located in the ER lumen. The novel Sec63 protein could thus represent a key component of the mammalian ER protein translocation machinery.
Posttranslational Protein Translocation Across the Membrane of the Endoplasmic Reticulum
Authors: Rapoport Tom A. , Matlack Kent E.S. , Plath Kathrin , Misselwitz Benjamin , Staeck Oliver 
Published: October 2004

AbstractPosttranslational protein translocation across the membrane of the endoplasmic reticulum is mediated by the Sec complex. This complex includes a transmembrane channel formed by multiple copies of the Sec61 protein. Translocation of a polypeptide begins when the signal sequence binds at a specific site within the channel. Binding results in the insertion of the substrate into the channel, possibly as a loop with a small segment exposed to the lumen. While bound, the signal sequence is in contact with both protein components of the channel and the lipid of the membrane. Subsequent movement of the polypeptide through the channel occurs when BiP molecules interact transiently with a luminal domain of the Sec complex, hydrolyze ATP, and bind to the substrate. Bound BiP promotes translocation by preventing the substrate from diffusing backwards through the channel, and thus acts as a molecular ratchet.
Import of Carrier Proteins into Mitochondria
Authors: Truscott Kaye N. , Pfanner Nikolaus 
Published: October 2004

AbstractCarrier proteins located in the inner membrane of mitochondria are responsible for the exchange of metabolites between the intermembrane space and the matrix of this organelle. All members of this family are nuclear-encoded and depend on translocation machineries for their import into mitochondria. Recently many new translocation components responsible for the import of carrier proteins were identified. It is now possible to describe a detailed import pathway for this class of proteins. This review highlights the contribution made by translocation components to the process of carrier protein import into mitochondria.
The T-Knot Motif Revisited
Authors: Polticelli Fabio , Pascarella Stefano , Bordo Domenico , Bolognesi Martino , Ascenzi Paolo 
Published: October 2004

AbstractThe T-knot scaffold, a disulphide-reinforced structural motif shared by several proteins with very different biological functions, has been defined as ‘a stretch of the protein chain which comprises two strands of a β-sheet and three loops, knotted by two disulphides into the shape of the letter T’. In this communication we show that the presence of a central β-sheet is not a required structural feature for proteins sharing the T-knot topology. Moreover, superposition of the three-dimensional structures of representative members of the T-knot family highlights a common and structurally well-defined core, formed by the two knotted disulphides, substituting for a larger residue-based hydrophobic core. These results suggest that folding and stability of the T-knot scaffold mainly depend on the geometry of the two knotted disulphides and on the loop length, and that the secondary structure elements are not a prerequisite for motif formation. Accordingly, a redefinition of the T-knot motif is proposed.
Synthesis, Cytotoxicity and Antitumor Activity of Platinum(II) Complexes of Cyclopentanecarboxylic Acid Hydrazide
Authors: Kushev Daniel , Gorneva Galina , Taxirov Svetoslav , Spassovska Nadejda , Grancharov Konstantin 
Published: October 2004

Abstract
New platinum(II) complexes of cyclopentanecarboxylic
acid hydrazide (cpcah) were prepared, characterized
by elemental analysis, IR and 1H NMR spectra,
and evaluated for in vitro cytotoxicity in Friend
leukemia (FL) and A2780 ovarian tumor cells, induction
of apoptosis in FL cells, as well as for in vivo antitumor
activity toward murine L1210 leukemia and Lewis lung
carcinoma. The spectral analyses indicated a cissquare
planar structure of the complexes with hydrazide
ligand coordinated via the NH2 group. The
compounds exerted significantly lower in vitro and
in vivo toxicities as compared with those of cisplatin
(cis-diamminedichloroplatinum(II), DDP). On the other
hand, the complex [Pt(NH3)(cpcah)Cl2] exhibited antitumor
activity against L1210 leukemia in mice comparable
to that of cisplatin, resulting at a dose of
42 mg/kg (administered 3 times) in a T/C (mean survival
time) of 280%. This compound displayed an in
vitro macromolecular synthesis inhibition pattern
similar to that of DDP. At concentrations close to the
cytostatic ones (10–20 μM) this complex, as well as
DDP, was able to induce apoptosis in FL cells as shown
by neutral comet assay and morphological analysis.
We concluded that there is a correlation between the
ability of platinum complexes to induce apoptosis and
their antitumor activity.
Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions
Authors: Blanche Stéphanie , Sun Xiuzhi 
Published: October 2004

AbstractThe objective of this study was to investigate the relationships between starch melt transition characteristics, extrusion conditions, and final product properties. Cornstarch was extruded using a corotating twin‐screw extruder at varying moisture content, medium/high screw configuration, and 300/400‐rpm screw speeds. Extrudates were evaluated for bulk density, expansion ratio, cell structure, bending strength, thermal and pasting properties. Temperature change (ΔT) was defined as the temperature difference between the native starch melting temperature and its melt temperature just behind the die during extrusion at a given moisture content. ΔT was significantly affected by starch moisture content and mechanical shearing, which controlled the melting behavior of the starch in the barrel. Amylose–lipid complex formation during extrusion increased as ΔT increased and leveled off at ΔT of about 20°C. Pasting peak viscosity of the starch extrudates decreased as ΔT increased and leveled off at ΔT of about 15°C. Within the same range of mechanical shearing intensity, extrudate bulk density and bending strength decreased linearly as ΔT increased. Extrudate expansion was negatively correlated to bulk density. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 277–290, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20017
Comparison of epoxy resins for applications in light‐emitting diodes
Authors: Huang Jan‐Chan , Chu Ying‐Po , Wei Ming , Deanin Rudolph D. 
Published: October 2004

AbstractEpoxy resin is a material commonly used for the encapsulation of light‐emitting diodes (LED). Three epoxy resins were chosen in this study: D.E.R.‐331 was a bisphenol A type epoxy resin, Eporite‐5630 was a bisphenol A type epoxy resin modified with a UV stabilizer, and ERL‐4221 was a cyclo‐aliphatic epoxy resin. The curing agent was methyl hexahydrophthalic anhydride (MHHPA), and the catalyst was tetra‐butyl ammonium bromide (TBAB). Thermal, environmental, and optical properties of the cured epoxy resins were studied. It was found that cured ERL‐4221 had better UV resistance, but other properties of ERL‐4221 were lower because of the internal stress generated during the curing process. D.E.R.‐331 showed better thermal stability, but the aromatic groups in the main chains caused sensitivity to photodegradation. Eporite‐5630 had the advantages of D.E.R.‐331 and better UV resistance than D.E.R.‐331 because of the addition of UV stabilizer. Among the three materials, Eporite‐5630 was the best choice of the balance properties for LED applications. This finding may assist in the selection of epoxy resins used in LED technology. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 298–306, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20018
Information asymmetry and the role of traceability systems
Authors: Hobbs Jill E. 
Published: October 2004

AbstractThe role of food traceability systems in resolving information asymmetry is explored. Three functions of traceability systems are identified: ex post reactive systems that allow the traceback of affected products in the event of a contamination problem so as to minimize social costs, ex post systems that facilitate the allocation of liability, and information systems that provide ex ante quality verification. A taxonomy of traceability systems illustrates the multidimensional nature of the information problems related to food safety and food quality. A model of ex ante quality verification and ex post traceability systems is used to demonstrate the different functions and incentives of a traceability system. Finally, examples of private sector and regulatory traceability initiatives are discussed within the context of the ex post and ex ante models developed in the paper. [EconLit citations: Q130; Q180; L150.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 397–415, 2004.
Assessing the efficiency of exchange rate‐linked subsidies (ERLS) for non‐price export promotion: The case of cotton
Authors: Paudel Laxmi , Adhikari Murali , Houston Jack E. , Kinnucan Henry W. 
Published: October 2004

AbstractNotwithstanding substantial federal financial support for the export promotion of agricultural products, ways to enhance the effectiveness of federal funding have not been discussed in empirical research. In this study, an equilibrium displacement framework was developed to evaluate whether the efficacy of export promotion expenditures could be increased by linking them with changes in the exchange rate. In our analysis, the gross gain to domestic cotton producers from the exchange rate linked subsidy scheme was positive. Findings support exchange rate linked subsidies for export promotion of agricultural products. [EconLit citations: Q110, Q130.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 481–493, 2004.
Logistics and supply chain strategies in grain exporting
Authors: Wilson William W. , Carlson Donald C.E. , Dahl Bruce L. 
Published: October 2004

AbstractThe grain shipping industry is highly competitive and has become technically advanced during the past decade. These changes, along with the introduction of innovative shipping mechanisms, have made logistics management an important source of opportunity and risk for grain shippers. A stochastic simulation model was developed to evaluate tradeoffs and effects of key variables on logistical costs in the grain supply chain for an individual firm. Average demurrage for the supply chain was $2.14 million ($0.70/mt or 1.8 cent/bu) with the highest demurrage costs for vessels and lowest for railcars. Of the random variables modeled, unexpected changes in export demand had the greatest impact on costs. [EconLit citation: Q130.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 449–464, 2004.
Calcium pump disorders of the skin
Authors: Foggia Lucie , Hovnanian Alain 
Published: October 2004

AbstractThe causes of Darier disease (DD) and Hailey–Hailey disease (HHD) have eluded clinicians and scientists for more than 60 years. DD is characterized by loss of adhesion between suprabasal epidermal cells associated with abnormal keratinization, while loss of epidermal cell‐to‐cell adhesion is predominant in HHD. The genes for both conditions have recently been identified using candidate positional cloning approaches. The gene for DD (ATP2A2) encodes a calcium transport ATPase of the sarco (endo)plasmic reticulum (SERCA2) Verboomen et al. [1992: Biochem J 286(Pt 2):591–595], while the gene for HHD (ATP2C1) codes for a secretory pathway for calcium and manganese transport ATPase of the Golgi apparatus (SPCA1) Hu et al. [2000: Nat Genet 24:61–65]. These results have provided completely new insights into the role of calcium and/or manganese in maintaining skin integrity. Although the precise disease mechanisms remain to be understood, these discoveries open a new field in research for the understanding and the treatment of these distressing disorders. © 2004 Wiley‐Liss, Inc.
Molecular genetics of hereditary hair and nail disease
Authors: van Steensel M.A.M. , van Geel M. , Steijlen P.M. 
Published: October 2004

AbstractHair and nail development have many similarities and are likely to share many developmental pathways. This is evident from the ectodermal dysplasias that affect both appendages. Of special interest are syndromic disorders as they show the effects of disturbances in molecular pathways that are essential for normal embryonic development. In this review, recent results from studies of syndrome affecting hair and nail development will be discussed. © 2004 Wiley‐Liss, Inc.
Progress in epidermolysis bullosa: Genetic classification and clinical implications
Authors: Uitto Jouni , Richard Gabriele 
Published: October 2004

AbstractEpidermolysis bullosa (EB), a heterogenous group of genodermatoses, is characterized by fragility and blistering of the skin associated with extracutaneous manifestations. Based on clinical severity, constellation of the phenotypic manifestations, and the level of tissue separation within the cutaneous basement membrane zone (BMZ), EB has been divided into distinct subcategories. Traditionally, these include the simplex, junctional, and dystrophic forms of EB, and recently attention has been drawn to hemidesmosomal variants demonstrating tissue separation at the level of the hemidesmosomes. Specific mutations in ten distinct genes expressed within the cutaneous BMZ have been delineated in >500 families with different variants of EB. The types of mutations, their positions along the affected genes, and their consequences at the mRNA and protein levels provide explanation for the phenotypic variability and genetic heterogeneity of this group of genodermatoses. Elucidation of mutations in different forms of EB has direct translational applications for improved diagnosis and molecularly based classification with prognostic implications as well as for genetic counseling and DNA‐based prenatal testing in families with EB. © 2004 Wiley‐Liss, Inc.
Zwischenmolekulare Wechselwirkungen in Lösung: eine vereinfachende Quantifizierungsmethode
Authors: Hunter Christopher A. 
Published: October 2004

AbstractMolekulare Erkennungsvorgänge in Lösung werden von vielen Faktoren beeinflusst. Dies hat bisher verhindert, dass die zwischenmolekularen Wechselwirkungen auf einer quantitativen Ebene verstanden werden. Unser gegenwärtiger Ansatz besteht darin, diese Effekte phänomenologisch in einzelne Wechselwirkungen aufzuteilen, sie zu klassifizieren, zu benennen und dann getrennt zu behandeln: aromatische Wechselwirkungen, Kation‐π‐Wechselwirkungen, CH‐O‐Wasserstoffbrücken und hydrophobe Wechselwirkungen sind einige Beispiele.1 Um hier Fortschritte zu erzielen, braucht es einen integrierten quantitativen Ansatz zur Bestimmung des relativen Ausmaßes der Wechselwirkungen, die das molekulare Erkennungsverhalten eines gegebenen Systems beeinflussen können. Hierzu wurde ein Modell entwickelt, das die theoretischen Ansätze und experimentellen Ergebnisse zu zwischenmolekularen Wechselwirkungen in der Gasphase, im festen Zustand und in Lösung stark vereinfacht beschreibt. Ziel ist es, eine halbquantitative thermodynamische Rangfolge dieser Effekte in Lösung bei Raumtemperatur zu erstellen.
Quantifying Intermolecular Interactions: Guidelines for the Molecular Recognition Toolbox
Authors: Hunter Christopher A. 
Published: October 2004

AbstractMolecular recognition events in solution are affected by many different factors that have hampered the development of an understanding of intermolecular interactions at a quantitative level. Our tendency is to partition these effects into discrete phenomenological fields that are classified, named, and divorced: aromatic interactions, cation–π interactions, CHO hydrogen bonds, short strong hydrogen bonds, and hydrophobic interactions to name a few.1 To progress in the field, we need to develop an integrated quantitative appreciation of the relative magnitudes of all of the different effects that might influence the molecular recognition behavior of a given system. In an effort to navigate undergraduates through the vast and sometimes contradictory literature on the subject, I have developed an approach that treats theoretical ideas and experimental observations about intermolecular interactions in the gas phase, the solid state, and solution from a single simplistic viewpoint. The key features are outlined here, and although many of the ideas will be familiar, the aim is to provide a semiquantitative thermodynamic ranking of these effects in solution at room temperature.
Glucose oxidase electrodes of poly(o‐anisidine), poly(o‐toluidine), and their copolymer as biosensors: A comparative study
Authors: Borole D. D. , Kapadi U. R. , Mahulikar P. P. , Hundiwale D. G. 
Published: October 2004

AbstractThin films of poly(o‐anisidine) (POA), poly(o‐toluidine) (POT), and their copolymer poly(o‐anisidine‐co‐o‐toluidine) (POA‐co‐POT) were electropolymerized in solutions containing 0.1M monomer(s) and 1M H2SO4 as an electrolyte through the application of a sequential linear potential scanning rate of 50 mV/s between −0.2 and 1.0 V versus an Ag/AgCl electrode on a platinum electrode. A simple technique was used to construct glucose sensors through the entrapment of glucose oxidase (GOD) in thin films of POA, POT, and their copolymer POA‐co‐POT, which were electrochemically deposited on a platinum plate in phosphate and acetate buffers. The maximum current response was observed for POA, POT, and POA‐co‐POT GOD electrodes at pH 5.5 and at a potential of 0.60 V (vs Ag/AgCl). The phosphate buffer yielded a fast response in comparison with the acetate buffer in amperometric measurements. The POT GOD electrode showed a fast response and was followed by POA‐co‐POT and POA GOD electrodes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1877–1884, 2004
Over‐expression of the p110β but not p110α isoform of PI 3‐kinase inhibits motility in breast cancer cells
Authors: Yip Shu‐Chin , El‐Sibai Mirvat , Hill Karen M. , Wu Haiyan , Fu Zheng , Condeelis John S. , Backer Jonathan M. 
Published: October 2004

AbstractPhosphoinositide 3‐kinase (PI 3‐kinase) activity is required for growth factor‐induced cytoskeletal regulation and cell migration. We previously found that in MTLn3 rat adenocarcinoma cells, EGF‐stimulated induction of actin barbed ends and lamellipod extension specifically requires the p85/p110α isoform of PI 3‐kinase. To further characterize signaling by distinct PI 3‐kinase isoforms, we have developed MTLn3 cells that transiently or stably overexpress either p110α or p110β. Transient overexpression of p110β inhibited EGF‐stimulated lamellipod extension, whereas p110α‐transfected cells showed normal EGF‐stimulated lamellipod extension. Similar results were obtained by overexpression of kinase‐dead p110β, suggesting that effects on cytoskeletal signaling were due to competition with p85/p110α complexes. Stable overexpression of p110α appeared to be toxic, based on the difficulty in obtaining stable overexpressing clones. In contrast, cells expressing a 2‐fold increase in p110β were readily obtainable. Interestingly, cells stably expressing p110β showed a marked inhibition of EGF‐stimulated lamellipod extension. Using computer‐assisted analysis of time‐lapse images, we found that overexpression of p110β caused a nearly complete inhibition of motility. Cells overexpressing p110β showed normal activation of Akt and Erk, suggesting that overall PI 3‐kinase signaling was intact. A chimeric p110 molecule containing the p85‐binding and Ras‐binding domains of p110α and the C2, helical, and kinase domains of p110β, was catalytically active yet also inhibited EGF‐stimulated lamellipod extension. These data highlight the differential signaling by distinct p110 isoforms. Identification of effectors that are differently regulated by p110α versus p110β will be important for understanding cell migration and its role in metastasis. Cell Motil. Cytoskeleton 59:180–188, 2004. © 2004 Wiley‐Liss, Inc.