bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pseudomonas aeruginosa
SoxR Does Not Conform to the Archetypal Paradigm for SoxR-Dependent Regulation of the Bacterial Oxidative Stress Adaptive Response
Authors: Palma Marco , Zurita Juan , Ferreras Julian A. , Worgall Stefan , Larone Davise H. , Shi Lei , Campagne Fabien , Quadri Luis E. N. 
Published: April 2005

ABSTRACT

SoxR is a transcriptional regulator that controls an oxidative stress response in
Escherichia coli
. The regulator is primarily activated by superoxide anion-dependent oxidation. Activated SoxR turns on transcription of a single gene,
soxS
, which encodes a transcriptional regulator that activates a regulon that includes dozens of oxidative stress response genes. SoxR homologues have been identified in many bacterial species, including the opportunistic pathogen
Pseudomonas aeruginosa
. However, the expected SoxR partner, SoxS, has not been found in
P. aeruginosa
. Thus, the primary gene target(s) of
P. aeruginosa
SoxR is unknown and the involvement of this regulator in the oxidative stress response of the bacterium remains unclear. We utilized transcriptome profiling to identify the
P. aeruginosa
SoxR regulon and constructed and characterized an unmarked
P. aeruginosa
Δ
soxR
mutant. We provide evidence indicating that
P. aeruginosa
SoxR activates a six-gene regulon in response to O
2
·−
-induced stress. The regulon includes three transcriptional units: (i) the recently identified
mexGHI
-
ompD
four-gene operon, which encodes a multidrug efflux pump system involved in quorum-sensing signal homeostasis; (ii) gene PA3718, encoding a probable efflux pump; and (iii) gene PA2274, encoding a probable monooxygenase. We also demonstrate that
P. aeruginosa
SoxR is not a key regulatory player in the oxidative stress response. Finally, we show that
P. aeruginosa
SoxR is required for virulence in a mouse model of intrapulmonary infection. These results demonstrate that the
E. coli
-based SoxRS paradigm does not hold in
P. aeruginosa
and foster new hypotheses for the possible physiological role of
P. aeruginosa
SoxR.
Induction of Nod1 and Nod2 Intracellular Pattern Recognition Receptors in Murine Osteoblasts following Bacterial Challenge
Authors: Marriott Ian , Rati Dana M. , McCall Samuel H. , Tranguch Susanne L. 
Published: April 2005

ABSTRACT

Osteoblasts produce an array of immune molecules following bacterial challenge that could recruit leukocytes to sites of infection and promote inflammation during bone diseases, such as osteomyelitis. Recent studies from our laboratory have shed light on the mechanisms by which this cell type can perceive and respond to bacteria by demonstrating the functional expression of members of the Toll-like family of cell surface pattern recognition receptors by osteoblasts. However, we have shown that bacterial components fail to elicit immune responses comparable with those seen following challenge with the intracellular pathogens salmonellae and
Staphylococcus aureus
. In the present study, we show that UV-killed bacteria and invasion-defective bacterial strains elicit significantly less inflammatory cytokine production than their viable wild-type counterparts. Importantly, we demonstrate that murine osteoblasts express the novel intracellular pattern recognition receptors Nod1 and Nod2. Levels of mRNA encoding Nod molecules and protein expression are significantly and differentially increased from low basal levels following exposure to these disparate bacterial pathogens. In addition, we have shown that osteoblasts express Rip2 kinase, a critical downstream effector molecule for Nod signaling. Furthermore, to begin to establish the functional nature of Nod expression, we show that a specific ligand for Nod proteins can significantly augment immune molecule production by osteoblasts exposed to either UV-inactivated bacteria or bacterial lipopolysaccharide. As such, the presence of Nod proteins in osteoblasts could represent an important mechanism by which this cell type responds to intracellular bacterial pathogens of bone.
Infection of the Reproductive Tract and Eggs with
Salmonella enterica
Serovar Pullorum in the Chicken Is Associated with Suppression of Cellular Immunity at Sexual Maturity
Authors: Wigley Paul , Hulme Scott. D. , Powers Claire , Beal Richard K. , Berchieri Angelo , Smith Adrian , Barrow Paul 
Published: April 2005

ABSTRACT

Salmonella enterica
serovar Pullorum causes persistent infections in laying hens. Splenic macrophages are the main site of persistence. At sexual maturity, numbers of bacteria increase and spread to the reproductive tract, which may result in vertical transmission to eggs or chicks. In this study we demonstrate that both male and female chickens may develop a carrier state following infection but that the increases in bacterial numbers and spread to the reproductive tract are phenomena restricted to hens, indicating that such changes are likely to be related to the onset of egg laying. The immunological responses during the carrier state and through the onset of laying in hens were determined. These indicate that chickens produce both humoral and T-cell responses to infection, but at the onset of laying both the T-cell response to
Salmonella
and nonspecific responses to mitogenic stimulation fall sharply in both infected and noninfected birds. The fall in T-cell responsiveness coincided with the increase in numbers of
Salmonella
serovar Pullorum and its spread to the reproductive tract. Three weeks after the onset of egg laying, T-cell responsiveness began to increase and bacterial numbers declined. Specific antibody levels changed little at the onset of laying but increased following the rise in bacterial numbers in a manner reminiscent of a secondary antibody response to rechallenge. These findings indicate that a nonspecific suppression of cellular responses occurs at the onset of laying and plays a major role the ability of
Salmonella
serovar Pullorum to infect the reproductive tract, leading to transmission to eggs. The loss of T-cell activity at the point of laying also has implications for
Salmonella enterica
serovar Enteritidis infection and transmission to eggs, along with its control by vaccination offering a “window of opportunity” in which infection may occur.
Synthetic Toll-Like Receptor 4 Agonists Stimulate Innate Resistance to Infectious Challenge
Authors: Cluff Christopher W. , Baldridge Jory R. , Stöver Axel G. , Evans Jay T. , Johnson David A. , Lacy Michael J. , Clawson Valerie G. , Yorgensen Vonnie M. , Johnson Craig L. , Livesay Mark T. , Hershberg Robert M. , Persing David H. 
Published: April 2005

ABSTRACTA compound family of synthetic lipid A mimetics (termed the aminoalkyl glucosaminide phosphates [AGPs]) was evaluated in murine infectious disease models of protection against challenge withListeria monocytogenesand influenza virus. For theListeriamodel, intravenous administration of AGPs was followed by intravenous bacterial challenge 24 h later. Spleens were harvested 2 days postchallenge for the enumeration of CFU. For the influenza virus model, mice were challenged with virus via the intranasal/intrapulmonary route 48 h after intranasal/intrapulmonary administration of AGPs. The severity of disease was assessed daily for 3 weeks following challenge. Several types of AGPs provided strong protection against influenza virus orListeriachallenge in wild-type mice, but they were inactive in the C3H/HeJ mouse, demonstrating the dependence of the AGPs on toll-like receptor 4 (TLR4) signaling for the protective effect. Structure-activity relationship studies showed that the activation of innate immune effectors by AGPs depends primarily on the lengths of the secondary acyl chains within the three acyl-oxy-acyl residues and also on the nature of the functional group attached to the aglycon component. We conclude that the administration of synthetic TLR4 agonists provides rapid pharmacologic induction of innate resistance to infectious challenge by two different pathogen classes, that this effect is mediated via TLR4, and that structural differences between AGPs can have dramatic effects on agonist activity in vivo.
A Monoclonal Antibody That Conveys In Vitro Killing and Partial Protection in Experimental Syphilis Binds a Phosphorylcholine Surface Epitope ofTreponema pallidum
Authors: Blanco David R. , Champion Cheryl I. , Dooley Alek , Cox David L. , Whitelegge Julian P. , Faull Kym , Lovett Michael A. 
Published: April 2005

ABSTRACTImmunization with purifiedTreponema pallidumouter membrane vesicles (OMV) has previously resulted in high-titer complement-dependent serum bactericidal activity. In this study, OMV immunization resulted in the isolation of a monoclonal antibody, M131, with complement-dependent killing activity. Passive immunization of rabbits with M131 administered intravenously conferred significant immunity demonstrated by the failure of syphilitic lesions to appear at 29% of intradermal challenge sites (7/24) and a mean delay of approximately 8 days to lesion appearance at the remaining sites (17/24). M131 not only bound to OMV and to the surfaces of intact motileT. pallidumcells but also bound to organisms whose outer membranes were removed, indicating both surface and subsurface locations for the killing target. This target was determined to be aT. pallidumlipid. Lipid extracted fromT. pallidumand made into liposomes bound M131. Reverse-phase high-pressure liquid chromatography separation and fraction collection mass spectrometry (LC-MS+) ofT. pallidumlipid showed that the target of M131 was phosphorylcholine. M131 binding required both liposome formation and a critical concentration of phospholipid containing phosphorylcholine, suggesting that the epitope has both a conformational and a compositional requirement. M131 did not react with red blood cells, which have phosphorylcholine-containing lipids in their exterior membrane leaflets, or with Venereal Disease Research Laboratory antigen that also contains phosphorylcholine, further indicating the specificity of M131. This is the first physical demonstration of an antigen on theT. pallidumsurface and indication that such a surface antigen can be a target of immunity.
Maturation of theLegionella pneumophila-Containing Phagosome into a Phagolysosome within Gamma Interferon-Activated Macrophages
Authors: Santic Marina , Molmeret Maëlle , Abu Kwaik Yousef 
Published: April 2005

ABSTRACTLegionella pneumophilais an intracellular pathogen that modulates the biogenesis of its phagosome to evade endocytic vesicle traffic. TheLegionella-containing phagosome (LCP) does not acquire any endocytic markers and is remodeled by the endoplasmic reticulum during early stages. Here we show that intracellular replication ofL. pneumophilais inhibited in gamma interferon (IFN-γ)-activated, bone marrow-derived mouse macrophages and IFN-γ-activated, human monocyte-derived macrophages in a dose-dependent manner. This inhibition of intracellular replication is associated with the maturation of the LCP into a phagolysosome, as documented by the acquisition of LAMP-2, cathepsin D, and lysosomal tracer Texas Red ovalbumin, and with the failure of the LCP to be remodeled by the rough endoplasmic reticulum. We conclude that IFN-γ-activated macrophages override the ability ofL. pneumophilato evade endocytic fusion and that the LCP is processed through the “default” endosomal-lysosomal degradation pathway.
The Concentration of Apolipoprotein A-I Decreases during Experimentally Induced Acute-Phase Processes in Pigs
Authors: Carpintero R. , Piñeiro M. , Andrés M. , Iturralde M. , Alava M. A. , Heegaard P. M. H. , Jobert J. L. , Madec F. , Lampreave F. 
Published: April 2005

ABSTRACTIn this work, apolipoprotein A-I (ApoA-I) was purified from pig sera. The responses of this protein after sterile inflammation and in animals infected withActinobacillus pleuropneumoniaeorStreptococcus suiswere investigated. Decreases in the concentrations of ApoA-I, two to five times lower than the initial values, were observed at 2 to 4 days. It is concluded that ApoA-I is a negative acute-phase protein in pigs.
Maximum Pressure Policies in Stochastic Processing Networks
Authors: Dai J. G. , Lin Wuqin 
Published: April 2005

Complex systems like semiconductor wafer fabrication facilities (fabs), networks of data switches, and large-scale call centers all demand efficient resource allocation. Deterministic models like linear programs (LP) have been used for capacity planning at both the design and expansion stages of such systems. LP-based planning is critical in setting a medium range or long-term goal for many systems, but it does not translate into a day-to-day operational policy that must deal with discreteness of jobs and the randomness of the processing environment. A stochastic processing network, advanced by J. Michael Harrison (2000, 2002, 2003), is a system that takes inputs of materials of various kinds and uses various processing resources to produce outputs of materials of various kinds. Such a network provides a powerful abstraction of a wide range of real-world systems. It provides high-fidelity stochastic models in diverse economic sectors including manufacturing, service, and information technology. We propose a family of maximum pressure service policies for dynamically allocating service capacities in a stochastic processing network. Under a mild assumption on network structure, we prove that a network operating under a maximum pressure policy achieves maximum throughput predicted by LPs. These policies are semilocal in the sense that each server makes its decision based on the buffer content in its serviceable buffers and their immediately downstream buffers. In particular, their implementation does not use arrival rate information, which is difficult to collect in many applications. We also identify a class of networks for which the nonpreemptive, non-processor-splitting version of a maximum pressure policy is still throughput optimal. Applications to queueing networks with alternate routes and networks of data switches are presented.
Amine Fluoride/Stannous Fluoride and Chlorhexidine Mouthwashes as Adjuncts to Single‐Stage Dental Implants: A Comparative Study
Authors: Horwitz Jacob , Machtei Eli E. , Zuabi Otman , Peled Micha 
Published: April 2005

Background: The growing popularity of non‐submerged dental implants in recent years requires a greater emphasis on microbial plaque control. Chlorhexidine (CHX), the most commonly used mouthwash in implant surgery, is sometimes associated with tooth staining and alteration in taste perception. Amine fluoride/stannous fluoride (AmF/SnF2) mouthwash has been shown to have anti‐infective properties; however, it has not been tested as an adjunct anti‐infective means in non‐submerged dental implants. The purpose of this trial was to compare AmF/SnF2 and CHX mouthwashes as adjuncts to single‐stage dental implants.Methods: Thirty‐three patients aged 34 to 79 (mean 54.30 ± 8.69 SD) requiring dental implants were accepted into the study. Following comprehensive periodontal therapy patients received one to three non‐submerged dental implants (maxilla: 17; mandible: 45; anterior: 3, posterior: 59). After surgery patients were given analgesics and antibiotics as well as 2,400 ml of coded mouthwash bottles previously randomized between the two above mentioned formulations. Clinical and radiographic parameters were recorded at baseline and 3 and 12 months post‐surgery.Results: Twelve‐month survival rates were 100% and 92.9% for the AmF/SnF2 and CHX groups, respectively. Compliance was slightly higher in the AmF/SnF2 group (84.35% ± 3.39% versus 78.15% ± 4.59% SE) but statistically similar. There was no statistically significant difference between the AmF/SnF2 and CHX groups in staining index at 3 months (1.519 ± 0.22 versus 1.457 ± 0.24 SE) and patient subjective evaluation of the mouthwashes. Radiographic bone loss was 0.79 ± 0.23 and 1 ± 0.13 SE at 3 months and 1.06 ± 0.13 and 1.27 ± 0.25 at 12 months for the CHX and AmF/SnF2 groups, respectively; the difference was statistically insignificant (P = 0.388 and 0.504, respectively).Conclusion: Both CHX and AmF/SnF2 mouthwashes can be used post‐surgically after one‐stage implant surgery. J Periodontol 2005;76: 334‐340.
An 8‐Year Retrospective Study: 1,100 Patients Receiving 1,557 Implants Using the Minimally Invasive Hydraulic Sinus Condensing Technique
Authors: Chen Leon , Cha Jennifer 
Published: April 2005

Background: For many clinicians, inadequate alveolar bone height and anatomical features of the maxillary sinus complicate sinus lift procedures and placement of endosseous implants. We present a new internal crestal approach that addresses these issues.Methods: Sinus burs and condensers of increasing width are used in conjunction with pliable atraumatic bone grafting mixture and hydraulic pressure from a surgical handpiece. The risk of a membrane perforation is minimized when the surgeon's tactile skill is administered in a two‐stage process to first loosen and then graft bone particulate under the Schneiderian membrane. Threaded implants can then be placed in the same visit and secured via primary closure.Results: A retrospective investigation of 1,100 cases showed that eight implants failed and 14 required longer healing periods in patients with alveolar ridge heights varying between <1 to 5 mm.Conclusions: Our experience suggests that hydraulic sinus condensing is a predictable and minimally invasive alternative for prosthetic rehabilitation of maxillary anterior and posterior regions in the presence of anatomical restrictions to implant placement. J Periodontol 2005;76:482‐491.
Microstructural and Nano‐Mechanical Characterisation of Multicomponent Composites Nanocrystalline Matrix
Authors: Woodcock T. G. , Alcalá G. , Mato S. , Gebert A. , Löser W. , Eckert J. , Schultz L. 
Published: April 2005

AbstractMulticomponent, Ti‐based, in situ formed composites with a nanocrystalline matrix are a promising new type of material for structural applications. The materials exhibit an excellent combination of mechanical properties resulting from the composite microstructure. This paper contains a detailed introduction to such materials and a review of the most recent developments in the specific areas of microstructural and nano‐mechanical characterization.
Cellular Ceramics in Metal Filtration
Authors: Olson R. A. , Martins L. C. B. 
Published: April 2005

AbstractIn most molten metal processing operations, the acts of melting, transporting and alloying the metal in preparation for casting into desired shapes introduces undesirable non‐metallic inclusions to the melt. Molten metals are highly reactive and tend to interact with gases and refractories during processing steps; undesirable phases are absorbed either as liquid or solid. Such examples of inclusion introduction are molten aluminum reacting with oxygen in air to form solid aluminum oxide, or molten cast iron reacting with oxygen in air to form liquid slag phases.
Konjugierte Oligomere mit terminaler Donor‐Acceptor‐Substitution
Authors: Meier Herbert 
Published: April 2005

AbstractKonjugierte Oligomere sind in theoretischer, präparativer und materialwissenschaftlicher Hinsicht eine prominente Substanzklasse. Die Push‐pull‐Substitution durch einen Elektronendonor an einem Ende und einen Elektronenacceptor am anderen Ende verleiht den Verbindungen D‐π‐A besondere optische und elektronische Eigenschaften. Der vorliegende Aufsatz schildert die grundsätzlichen Strategien zur Synthese solcher Oligomerenreihen mit n Wiederholungseinheiten (n=1, 2, 3, 4, …︁) und die für ihre linearen und nichtlinearen optischen Eigenschaften (Absorption, Frequenzverdoppelung und ‐verdreifachung) geltenden Gesetzmäßigkeiten. Aus den chemischen, physikalischen und theoretischen Aspekten der push‐pull‐substituierten konjugierten Oligomere soll sich ein interdisziplinäres Bild dieser Verbindungsklasse zusammenfügen.
Molecular Organization and Signal Transduction at Intermembrane Junctions
Authors: Groves Jay T. 
Published: April 2005

AbstractSurfaces create an environment in which multiple forces conspire together to yield a wealth of complex chemical processes. This is especially true of cell membranes, whose fluidity and flexibility enables responsive feedback with surface chemical interactions in ways not generally seen with inorganic materials. Spatial pattern formation of cell‐surface proteins at intermembrane junctions provides many beautiful examples of these phenomena, and is also emerging as a functional aspect of intercellular signaling. Correspondingly, the study of interactions of cell‐membrane surfaces is attracting significant attention from cell biologists and physical chemists alike. This convergence is fueled be recent, exquisite observations of protein pattern formation events within living immunological synapses along with parallel advances in membrane reconstitution, manipulation, and imaging technologies.
Polyoxometalate Monolayers in Langmuir–Blodgett Films
Authors: Clemente‐León Miguel , Coronado Eugenio , Gómez‐García Carlos J. , Mingotaud Christophe , Ravaine Serge , Romualdo‐Torres Gemma , Delhaès Pierre 
Published: April 2005

AbstractLangmuir and Langmuir–Blodgett (LB) films of a variety of polyoxometalates of different shapes, sizes, and charges were prepared by taking advantage of the adsorption properties of these polyanions on a positively charged monolayer of an organic surfactant spread on water. Three different aspects were investigated. 1) The electrochemical and electrochromic properties of LB films containing the easily reducible polyoxoanion [P2Mo18O62]6−. Absorbance changes of these LB films deposited onto an ITO substrate have been induced by repeated switching of the applied potential. These changes are due to the formation of the colored reduced forms of the polyanion. Coloration and bleaching of the LB film occur very quickly and are reversible. 2) The preparation of LB films based on magnetic polyoxometalates, such as the Keggin anions, [CoW12O40]6− and [SiMn(OH2)W11O39]6−, or containing magnetic clusters of increasing nuclearities such as [Co4(H2O)2(PW9O34)2]10− and [Co4(H2O)2(P2W15O62)2]16− based on a Co4O16 ferromagnetic cluster, and the polyoxometalates [Co9(OH)3(H2O)6(HPO4)2(PW9O34)3]16− and [Ni9(OH)3(H2O)6(HPO4)2(PW9O34)3]16− based on a nonanuclear M9O36 cluster. 3) The preparation of LB films of the giant heteropolyoxomolybdate, [Na3(NH4)12][Mo57Fe6(NO)6O174(OH)3(H2O)24]⋅76 H2O.