bluuebunny/crossref_metadata_2025_split huggingface dataset:
The quasi‐autonomous agency in an ambiguous environment: the Centrelink case
Authors: Halligan John 
Published: April 2004

AbstractAustralia's Centrelink provides an unique experiment with the integration of a variety of social services through a single quasi‐autonomous organisation. This multi‐functional agency delivers services to a number of clients while subject to a range of external and internal imperatives. The case indicates the complexities in managing the interface between policy department and service delivery agency and the limitations of operating with purchaser‐provider arrangements as a basis for relationships. Copyright © 2004 John Wiley & Sons, Ltd.
Proteomic analysis of agar gel‐entrapped Pseudomonas aeruginosa
Authors: Vilain Sébastien , Cosette Pascal , Hubert Marie , Lange Catherine , Junter Guy‐Alain , Jouenne Thierry 
Published: April 2004

AbstractWe have compared the protein maps of agar‐entrapped Pseudomonas aeruginosa cells to those of free counterparts grown in the presence or absence of the immobilized‐cell gel support. Principal component analyses (PCAs) were used to interpret spot quantity variations observed on electropherograms obtained by two‐dimensional gel electrophoresis. PCA of the data matrix (923 rows×6 columns) in which spot density values were standardized horizontally extracted three principal components (PCs) with eigenvalues higher than 1, accounting together for 71.6% of the variability in the data. Principal component 1 (PC1) opposed free (F) and agar‐entrapped (AE) cultures, with a low contribution of agar‐released, free (ARF) cultures to PC1. Inversely, the contribution of ARF cultures to PC2 was high, opposing those of AE and F cultures. Component 3 was related to the duration of incubation. Only 10% of total proteins were upregulated in AE cells during the first 18 h of incubation, the number of underexpressed peptides balancing that of overexpressed ones. Downregulation clearly became the dominant tendency when the incubation time was extended to 48 h. These results demonstrate that AE and ARF bacteria are physiologically different from F organisms.
Nano‐Scale Tungsten Oxides for Metastable Intermolecular Composites
Authors: Perry W. Lee , Smith Bettina L. , Bulian Christopher J. , Busse James R. , Macomber Clay S. , Dye Rob C. , Son Steven F. 
Published: April 2004

AbstractTungsten oxides are of interest as an oxidant for metals in metastable intermolecular composites, a nano‐scale powder useful for such applications as electric matches and gun primers. Smaller particles typically lead to faster reactions and we have synthesized nano‐scale WO3using wet chemistry. Ammonium paratungstate was dissolved in acid. Tungstic acid was precipitated by addition to distilled water and the resulting powder was dried. Analysis by X‐ray diffraction, Raman spectroscopy and electron microscopy revealed hydrated WO3, having approximately 100 nm×7 nm platelet morphology. Thermal treatment in air at 200 °C or 400 °C removed water, forming cubic or monoclinic WO3, respectively. Tungsten forms other stable oxides and we accessed WO2by reducing WO3in dilute H2at 650 °C. Reaction performance of these WOx‐materials, mixed with nano‐Al at various stoichiometries, is reported. Open‐tray burn velocity reached 250 m/s. Pressure cell experiments found a maximum pressure of 1.45 MPa and maximum pressurization rate of 500 GPa/s. These maximum pressures and rates occurred very near a stoichiometric mixture of the Al and WO3.
Induction and function of CYR61 (CCN1) in prostatic stromal and epithelial cells: CYR61 is required for prostatic cell proliferation
Authors: Sakamoto Shinji , Yokoyama Masahiro , Aoki Michiko , Suzuki Kensuke , Kakehi Yoshiyuki , Saito Yutaka 
Published: April 2004

AbstractBACKGROUNDCYR61 is an extracellular matrix‐associated protein that promotes adhesion, migration, and proliferation of endothelial cells and fibroblasts. Prostate enlargement, which frequently causes the urethral compression, is often histologically observed as stromal and epithelial hyperplasia in an enlarged gland. To determine whether or not CYR61 has relevance to the progression of benign prostatic hyperplasia (BPH), we investigated the induction of CYR61, and also examined its function in both prostatic stromal and epithelial cells.METHODSRecombinant CYR61 protein was used for the examination of the activity of CYR61 as to cell adhesion and proliferation. Quantitative reverse transcription‐polymerase chain reaction (RT‐PCR) was utilized to screen for inducers of the CYR61 gene in prostatic cells. Finally, the effects of an anti‐sense oligonucleotide, which could reduce the production of CYR61, on the morphology and growth of prostatic cells were also examined.RESULTSRecombinant CYR61 protein promotes prostatic cell adhesion and proliferation. The mRNA for CYR61, a growth factor‐inducible immediate early gene, was markedly induced by fetal bovine serum (FBS) within 1 hr, and strongly induced by transforming growth factor‐β1 (TGF‐β) for at least 19 hr following stimulation. The suppression of CYR61 production with an anti‐sense oligonucleotide causes obvious morphological changes of prostatic cells. Furthermore, we have shown that CYR61 is necessary, at least in part, for FBS‐induced prostatic cell proliferation, because dramatic inhibition of cellular growth was caused by the suppression of CYR61 production with the addition of the anti‐sense oligonucleotide before FBS stimulation.CONCLUSIONSIn this study, we demonstrate that serum growth factors induce the CYR61 gene in both stromal and epithelial cells, and that CYR61 plays functional roles in cell adhesion, morphology, and proliferation, supporting its involvement in benign prostatic enlargement. These results strongly suggest that CYR61 is a key molecule, and therefore could be a potential therapeutic target in prostatic hyperplastic growth. © 2004 Wiley‐Liss, Inc.
Lesions predictive for prostate cancer in a screened population: First and second screening round findings
Authors: Postma Renske , Roobol Monique , Schröder Fritz H. , van der Kwast Theodorus H. 
Published: April 2004

AbstractBACKGROUNDWe evaluated the incidence of prostate cancer, high‐grade prostatic intraepithelial neoplasia (PIN) and lesions suspicious for prostate cancer (LSPC) in sextant biopsies in two subsequent screening rounds at a 4‐year interval and their predictive value for subsequent prostate cancer detection.METHODSIn the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer (ERSPC), 4,117 men underwent sextant biopsy in the 1st screening round. The 2nd round was performed at a 4‐year interval and biopsies were taken in 1,840 men.RESULTSThe incidences of prostate cancer, LSPC and PIN in the 1st, respectively 2nd round were 24.6, resp. 19.9% (P = 0.001), 2.7, resp. 2.8% and 0.8, resp. 2.5% (P < 0.0001). Prostate cancer incidence after repeat biopsy for LSPC in the 1st, respectively 2nd round was 36.7 and 17.0%, and after repeat biopsy for PIN 13.3% in both rounds, respectively. Men with a benign biopsy in the 1st round had a significantly lower prostate cancer incidence in the 2nd round compared to men who did not undergo biopsy in the 1st round (10.7 vs. 22.7%, P < 0.0001).CONCLUSIONSThe decrease of prostate cancer detection in the 2nd round was associated with an increase in the incidence of PIN. Strikingly, LSPC diagnosed during the 1st round, but not during the 2nd round were predictive for prostate cancer, while isolated PIN was never predictive for prostate cancer. PIN shoud not be an indication for repeat biopsy in a screening population. Importantly a 1st round benign biopsy outcome proved to be a negative predictor of subsequent prostate cancer detection. © 2004 Wiley‐Liss, Inc.
Inhibitory effect of IL‐6‐induced neuroendocrine cells on prostate cancer cell proliferation
Authors: Wang Qingcai , Horiatis Dimitris , Pinski Jacek 
Published: April 2004

AbstractBACKGROUNDThe role of increased neuroendocrine (NE) differentiation in prostate cancer (PCA) is not well understood. Long‐term exposure of the prostate cancer cell line LNCaP to high concentrations of the cytokine interleukin‐6 (IL‐6) results in permanent transdifferentiation of these cells into a NE phenotype. In this study, we evaluated the effect of IL‐6‐induced NE cells on the growth of the PCA cell lines LNCaP, PC‐3, and DU‐145 in vitro.RESULTSCo‐culture of NE cells with PCA cells significantly inhibited DNA synthesis in all three PCA cell lines by 30–90% compared to controls. NE cell co‐culture resulted in an increased percentage of PCA cells arrested in the S‐phase of cell cycle and PCA cell apoptosis.CONCLUSIONSOur results imply that NE cells suppress the proliferation of surrounding PCA cells by release of inhibitory factors. © 2004 Wiley‐Liss, Inc.
Determining Uses and Gratifications for the Internet
Authors: Stafford Thomas F. , Stafford Marla Royne , Schkade Lawrence L. 
Published: April 2004

ABSTRACTUses and gratifications (U&G) is a media use paradigm from mass communications research that guides the assessment of consumer motivations for media usage and access. It has been used previously in research and decision making related to the promotion of emerging radio and television media. Recent adaptations of U&G research to the Internet are incomplete and have not identified important new Internet‐specific gratifications. This paper empirically derives dimensions of consumer Internet use and usage gratifications among customers of a prominent Internet Service Provider (ISP). Results describe three key dimensions related to consumer use of the Internet, including process and content gratifications as previously found in studies of television, as well as an entirely new social gratification that is unique to Internet use. All three dimensions of gratification are relevant to managing the Internet as a commercial medium, and measures developed from the gratification profiles identified here can serve as trait‐valid scales in future Internet and e‐commerce research.
Selecting Influential Business‐to‐Business Customers in New Product Development: Relational Embeddedness and Knowledge Heterogeneity Considerations
Authors: Bonner Joseph M. , Walker Orville C. 
Published: April 2004

This study examines how the most influential business‐to‐business (B2B) customers, both existing and potential, involved in providing input to a new product development (NPD) project influence new product advantage. As the relational literature suggests, involving customers who have had close and embedded relationships with a firm's new product organization, such as a firm's largest customers, and customers who have been involved in past collaborative activities, should lead to the development of superior products. To the contrary, the innovation literature suggests that a firm may become too close to its large, embedded customers resulting in less innovation and in lower performing products. Also, the relationship between the heterogeneity of the knowledge of the most influential customers and new product advantage is examined. A contingency perspective is hypothesized such that the degree of product newness sought in the project moderates the effects of both relational embeddedness and knowledge heterogeneity on new product advantage.Empirical findings from a sample of 137 NPD projects support this contingency view. For projects seeking to develop incremental products, where the product being developed is an extension or an enhancement to an existing product, new product advantage tended to be higher in projects using embedded or homogeneous customers. For incremental projects, projects using less‐embedded or heterogeneous customers tended to have lower product performance. For projects following a highly innovative product strategy, new product advantage tended to be higher in projects that involved heterogeneous customers. These heterogeneous customers provided NPD projects with a diversity of perspectives, competencies, and experiences that fostered significant product innovations.The study contributes to the literature by empirically testing relational and innovation theories in NPD projects and by providing evidence on the importance of relational embeddedness and knowledge heterogeneity in selecting influential customers in NPD projects.
Solution structure and domain architecture of the divisome protein FtsN
Authors: Yang Ji‐Chun , Van Den Ent Fusinita , Neuhaus David , Brevier Julian , Löwe Jan 
Published: April 2004

SummaryProkaryotic cell division occurs through the formation of a septum, which in Escherichia coli requires coordination of the invagination of the inner membrane, biosynthesis of peptidoglycan and constriction of the outer membrane. FtsN is an essential cell division protein and forms part of the divisome, a putative complex of proteins located in the cytoplasmic membrane. Structural analyses of FtsN by nuclear magnetic resonance (NMR) reveals an RNP‐like fold at the C‐terminus (comprising residues 243–319), which has significant sequence homology to a peptidoglycan‐binding domain. Sequential deletion mutagenesis in combination with NMR shows that the remaining of the periplasmic region of FtsN is unfolded, with the exception of three short, only partially formed helices following the trans‐membrane helix. Based on these findings we propose a model in which FtsN, anchored in the inner membrane, bridges over to the peptidoglycan layer, thereby enabling the coordination of the divisome and the murein‐shaping machinery in the periplasm.
Binding to pyruvylated compounds as an ancestral mechanism to anchor the outer envelope in primitive bacteria
Authors: Cava Felipe , De Pedro Miguel A. , Schwarz Heinz , Henne Anke , Berenguer José 
Published: April 2004

SummaryElectron microscopy of isolated cell walls of the ancient bacterium Thermus thermophilus revealed that most of the peptidoglycan (PG) surface, apart from the septal region, was shielded against specific αPG antibodies. On the other hand, an antiserum raised against S‐layer‐attached cell wall fragments (αSAC) bound to most of the surface except for the septal regions. Treatments with α‐amylase and pronase E made the entire cell wall surface uniformly accessible to αPG and severely decreased the binding of αSAC. We concluded that a layer of strongly bound secondary cell wall polymers (SCWPs) covers most of the cell wall surface in this ancient bacterium. A preliminary analysis revealed that such SCWPs constitute 14% of the cell wall and are essentially composed of sugars. Enzyme treatments of the cell walls revealed that SCWP was required in vitro for the binding of the S‐layer protein through the S‐layer homology (SLH) motif. The csaB gene was necessary for the attachment of the S‐layer–outer membrane (OM) complex to the cell wall in growing cells of T. thermophilus. In vitro experiments confirmed that cell walls from a csaB mutant bound to the S‐layer with a much lower affinity (∼1/10) than that of the wild type. CsaB was found to be required for pyruvylation of components of the SCWP and for immunodetection with α‐SAC antiserum. Therefore, the S‐layer–OM complex of T. thermophilus binds to the cell wall through the SLH motif of the S‐layer protein via a strong interaction with a highly immunogenic pyruvylated component of the SCWP. Immuno‐cross‐reactive compounds were detected with αSAC on cell walls of other Thermus spp. and in the phylogenetically related microorganism Deinococcus radiodurans. These results imply that the interaction between the SLH motif and pyruvylated components of the cell wall arose early during bacterial evolution as an ancestral mechanism for anchoring proteins and outer membranes to the cell walls of primitive bacteria.
Natural transformation and phase variation modulation in Neisseria meningitidis
Authors: Alexander Heather L. , Richardson Anthony R. , Stojiljkovic Igor 
Published: April 2004

Summary Neisseria meningitidis has evolved the ability to control the expression‐state of numerous genes by phase variation. It has been proposed that the process aids this human pathogen in coping with the diversity of microenvironments and host immune systems. Therefore, increased frequencies of phase variation may augment the organism's adaptability and virulence. In this study, we found that DNA derived from various neisserial co‐colonizers of the human nasopharynx increased N. meningitidis switching frequencies, indicating that heterologous neisserial DNA modulates phase variation in a transformation‐dependent manner. In order to determine whether the effect of heterologous DNA was specific to the Hb receptor, HmbR, we constructed a Universal Rates of Switching cassette (UROS). With this cassette, we demonstrated that heterologous DNA positively affects phase variation throughout the meningococcal genome, as UROS phase variation frequencies were also increased in the presence of neisserial DNA. Overexpressing components of the neisserial mismatch repair system partially alleviated DNA‐induced changes in phase variation frequencies, thus implicating mismatch repair titration as a cause of these transformation‐dependent increases in switching. The DNA‐dependent effect on phase variation was transient and may serve as a mechanism for meningococcal genetic variability that avoids the fitness costs encountered by global mutators.
EzrA prevents aberrant cell division by modulating assembly of the cytoskeletal protein FtsZ
Authors: Haeusser Daniel P. , Schwartz Rachel L. , Smith Alison M. , Oates Michelle Erin , Levin Petra Anne 
Published: April 2004

SummaryIn response to a cell cycle signal, the cytoskeletal protein FtsZ assembles into a ring structure that establishes the location of the division site and serves as a framework for assembly of the division machinery. A battery of factors control FtsZ assembly to ensure that the ring forms in the correct position and at the precise time. EzrA, a negative regulator of FtsZ ring formation, is important for ensuring that the ring forms only once per cell cycle and that cytokinesis is restricted to mid‐cell. EzrA is distributed throughout the plasma membrane and localizes to the ring in an FtsZ‐dependent manner, suggesting that it interacts directly with FtsZ to modulate assembly. We have performed a series of experiments examining the interaction between EzrA and FtsZ. As little as twofold overexpression of EzrA blocks FtsZ ring formation in a sensitized genetic background, consistent with its predicted function. A purified EzrA fusion protein interacts directly with FtsZ to block assembly in vitro. Although EzrA is able to inhibit FtsZ assembly, it is unable to disassemble preformed polymers. These data support a model in which EzrA interacts directly with FtsZ at the plasma membrane to prevent polymerization and aberrant FtsZ ring formation.
A suf operon requirement for Fe–S cluster assembly during iron starvation in Escherichia coli
Authors: Outten F. Wayne , Djaman Ouliana , Storz Gisela 
Published: April 2004

SummaryThe suf and isc operons of Escherichia coli have been implicated in Fe–S cluster assembly. However, it has been unclear why E. coli has two systems for Fe–S cluster biosynthesis. We have examined the regulatory characteristics and mutant phenotypes of both operons to discern if the two operons have redundant functions or if their cellular roles are divergent. Both operons are similarly induced by hydrogen peroxide and the iron chelator 2,2′‐dipyridyl, although by different mechanisms. Regulation of the isc operon is mediated by IscR, whereas the suf operon requires OxyR and IHF for the response to oxidative stress and Fur for induction by iron starvation. Simultaneous deletion of iscS and most suf genes is synthetically lethal. However, although the suf and isc operons have overlapping functions, they act as distinct complexes because the SufS desulphurase alone cannot substitute for the IscS enzyme. In addition, suf deletion mutants are more sensitive to iron starvation than isc mutants, and the activity of the Fe–S enzyme gluconate dehydratase is diminished in the suf mutant during iron starvation. These findings are consistent with the model that the isc operon encodes the housekeeping Fe–S cluster assembly system in E. coli, whereas the suf operon is specifically adapted to synthesize Fe–S clusters when iron or sulphur metabolism is disrupted by iron starvation or oxidative stress.
Characterization of a complex chemosensory signal transduction system which controls twitching motility in Pseudomonas aeruginosa
Authors: Whitchurch Cynthia B. , Leech Andrew J. , Young Michael D. , Kennedy Derek , Sargent Jennifer L. , Bertrand Jacob J. , Semmler Annalese B. T. , Mellick Albert S. , Martin Paul R. , Alm Richard A. , Hobbs Matthew , Beatson Scott A. , Huang Bixing , Nguyen Lam , Commolli James C. , Engel Joanne N. , Darzins Aldis , Mattick John S. 
Published: April 2004

SummaryVirulence of the opportunistic pathogen Pseudomonas aeruginosa involves the coordinate expression of a wide range of virulence factors including type IV pili which are required for colonization of host tissues and are associated with a form of surface translocation termed twitching motility. Twitching motility in P. aeruginosa is controlled by a complex signal transduction pathway which shares many modules in common with chemosensory systems controlling flagella rotation in bacteria and which is composed, in part, of the previously described proteins PilG, PilH, PilI, PilJ and PilK. Here we describe another three components of this pathway: ChpA, ChpB and ChpC, as well as two downstream genes, ChpD and ChpE, which may also be involved. The central component of the pathway, ChpA, possesses nine potential sites of phosphorylation: six histidine‐containing phosphotransfer (HPt) domains, two novel serine‐ and threonine‐containing phosphotransfer (SPt, TPt) domains and a CheY‐like receiver domain at its C‐terminus, and as such represents one of the most complex signalling proteins yet described in nature. We show that the Chp chemosensory system controls twitching motility and type IV pili biogenesis through control of pili assembly and/or retraction as well as expression of the pilin subunit gene pilA. The Chp system is also required for full virulence in a mouse model of acute pneumonia.
The molecular basis of fibronectin‐mediated bacterial adherence to host cells
Authors: Schwarz‐Linek Ulrich , Höök Magnus , Potts Jennifer R. 
Published: April 2004

SummaryMany pathogenic Gram‐positive bacteria produce cell wall‐anchored proteins that bind to components of the extracellular matrix (ECM) of the host. These bacterial MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) are thought to play a critical role in infection. One group of MSCRAMMs, produced by staphylococci and streptococci, targets fibronectin (Fn, a glycoprotein found in the ECM and body fluids of vertebrates) using repeats in the C‐terminal region of the bacterial protein. These bacterial Fn‐binding proteins (FnBPs) mediate adhesion to host tissue and bacterial uptake into non‐phagocytic host cells. Recent studies on interactions between the host and bacterial proteins at the residue‐specific level and on the mechanism of host cell invasion are providing a much clearer picture of these processes.