bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visualization of
Proteus mirabilis
Morphotypes in the Urinary Tract: the Elongated Swarmer Cell Is Rarely Observed in Ascending Urinary Tract Infection
Authors: Jansen Angela M. , Lockatell C. Virginia , Johnson David E. , Mobley Harry L. T. 
Published: May 2003

ABSTRACT

Proteus mirabilis
, a common cause of nosocomial and catheter-associated urinary tract infection, colonizes the bladder and ascends the ureters to the proximal tubules of the kidneys, leading to the development of acute pyelonephritis.
P
.
mirabilis
is capable of swarming, a form of multicellular behavior in which bacteria differentiate from the short rod typical of members of the family
Enterobacteriaceae
, termed the swimmer cell, into hyperflagellated elongated bacteria capable of rapid and coordinated population migration across surfaces, called the swarmer cell. There has been considerable debate as to which morphotype predominates during urinary tract infection.
P
.
mirabilis
(pBAC001), which expresses green fluorescent protein in both swimming and swarming morphotypes, was constructed to quantify the prevalence of each morphotype in ascending urinary tract infection. Transurethral inoculation of
P
.
mirabilis
(pBAC001) resulted in ascending urinary tract infection and kidney pathology in mice examined at both 2 and 4 days postinoculation. Using confocal microscopy, we were able to investigate the morphotypes of the bacteria in the urinary tract. Of 5,087 bacteria measured in bladders, ureters, and kidneys, only 7 (0.14%) were identified as swarmers. MR/P fimbria expression, which correlates with the swimmer phenotype, is prevalent on bacteria in the ureters and bladder. We conclude that, by far, the predominant morphotype present in the urinary tract during ascending infection is the short rod-the swimmer cell.
Listeriolysin O-Mediated Calcium Influx Potentiates Entry ofListeria monocytogenesinto the Human Hep-2 Epithelial Cell Line
Authors: Dramsi Shaynoor , Cossart Pascale 
Published: May 2003

ABSTRACTTo investigate factors which modulate the entry ofListeria monocytogenesinto mammalian cells, we have analyzed the role of Ca2+. We show thatL. monocytogenesinduced Ca2+transients into the human Hep-2 epithelial cell line. The nonpathogenic speciesL. innocuaor aL. monocytogenesmutant strain defective in listeriolysin O (LLO) production was unable to induce these calcium fluxes. Addition of plasma membrane calcium channel antagonists or chelation of extracellular calcium markedly reducedL. monocytogenesentry. In contrast, chelation of host cytosolic Ca2+or blockade of Ca2+release from intracellular stores did not affect invasion. These results indicate thatL. monocytogenes-induced mobilization of extracellular Ca2+by LLO and activation of downstream Ca2+-dependent signaling are required for efficient cell invasion.
The FimH A27V Mutation Is Pathoadaptive for Urovirulence in
Escherichia coli
B2 Phylogenetic Group Isolates
Authors: Hommais Florence , Gouriou Stéphanie , Amorin Christine , Bui Hung , Rahimy Mohamed Chérif , Picard Bertrand , Denamur Erick 
Published: May 2003

ABSTRACT

Correlations between FimH mutations and virulence were established by studying a collection of human commensal and extraintestinal pathogenic
Escherichia coli
natural isolates. Pathoadaptive (A27V and, to a lesser extent, A119V) and “commensal-adaptive” (A202V) mutations were evidenced in B2 phylogenetic group strains.
fimH
phylogenetic analysis indicates that these pathoadaptive mutations occurred several times.
Helicobacter pylori
Supernatants Cause Epithelial Cytoskeletal Disruption That Is Bacterial Strain and Epithelial Cell Line Dependent but Not Toxin VacA Dependent
Authors: Bebb James R. , Letley Darren P. , Rhead Joanne L. , Atherton John C. 
Published: May 2003

ABSTRACT

We show here that
Helicobacter pylori
broth culture supernatants disrupt the actin cytoskeleton of epithelial cell lines, leading to cell rounding and apoptosis through anoikis. We demonstrate that there are marked quantitative differences between strains and that there are different cell line sensitivities. By constructing VacA null isogenic mutants, we show that the effect is not due to the vacuolating cytotoxin.
Vaccine-Induced Protection againstHelicobacter pyloriin Mice Lacking Both Antibodies and Interleukin-4
Authors: Garhart Christine A. , Nedrud John G. , Heinzel Frederick P. , Sigmund Norma E. , Czinn Steven J. 
Published: May 2003

ABSTRACTTo test the hypothesis that a Th2 response toHelicobacter pyloriis necessary for protection and to address the possibility that humoral and Th2 cellular responses may compensate for each other, we generated mice deficient in both interleukin-4 (IL-4) and antibodies. The immunized double-knockout mice were protected fromH. pylorichallenge, as were the parental strains and wild-type C57BL/6 mice. Neutralization of IL-4 in B-cell-deficient mice did not prevent protection. Immunized IL-5-deficient mice were also protected. Thus, IL-4 and IL-5 are not essential for protection.
Cytolethal Distending Toxin Gene Cluster in Enterohemorrhagic
Escherichia
coli
O157:H
−
and O157:H7: Characterization and Evolutionary Considerations
Authors: Janka Andreas , Bielaszewska Martina , Dobrindt Ulrich , Greune Lilo , Schmidt M. Alexander , Karch Helge 
Published: May 2003

ABSTRACT

We identified a cytolethal distending toxin (
cdt
) gene cluster in 87, 6, and 0% of sorbitol-fermenting (SF) enterohemorrhagic
Escherichia
coli
(EHEC) O157:H
−
, EHEC O157:H7, and
E
.
coli
O55:H7/H
−
strains, respectively. The toxin was expressed by the wild-type EHEC O157 strains and by a
cdt
-containing cosmid from a library of SF EHEC O157:H
−
strain 493/89. The
cdt
flanks in strain 493/89 were homologous to bacteriophages P2 and lambda. Our data demonstrate that
cdt
, encoding a potential virulence factor, is present in the EHEC O157 complex and suggest that
cdt
may have been acquired by phage transduction.
Complete Sequence of the
cap
Locus of
Haemophilus influenzae
Serotype b and Nonencapsulated b Capsule-Negative Variants
Authors: Satola Sarah W. , Schirmer Patricia L. , Farley Monica M. 
Published: May 2003

ABSTRACT

The complete capsule (
cap
) loci from three
Haemophilus influenzae
strains, one serotype b (Hib) and two nonencapsulated b capsule-negative variants, were sequenced. Two new open reading frames,
hcsA
and
hcsB
, were identified in region III and thought to be involved in postpolymerization modification of the capsule. The location of the
cap
locus in the
Haemophilus influenzae
chromosome was identified within section 97 of the Rd genome (chromosomal coordinates 1074542 to 1086327) and found to be the same for the Hib and two Hib
−
strains as well as some other encapsulated division I
H. influenzae
strains.
Involvement of Nicotinic Acetylcholine Receptors in Controlling
Chlamydia
pneumoniae
Growth in Epithelial HEp-2 Cells
Authors: Yamaguchi Hiroyuki , Friedman Herman , Yamamoto Yoshimasa 
Published: May 2003

ABSTRACT

Nicotinic acetylcholine receptors (nAChRs) play an essential role in neurotransmission. Recent studies have indicated that nAChRs may be involved in the regulation of some bacterial infections through immunological mechanisms in macrophages. However, the regulation of infection with
Chlamydia
pneumoniae
, which is a ubiquitous pneumonia-causing bacterium, by an nAChR-mediated mechanism is still unclear. In the present study, it was found that stimulation of nAChRs with ligands such as nicotine and acetylcholine altered the growth of
C
.
pneumoniae
in epithelial HEp-2 cells. Thus, the results revealed a possible pathophysiological role of nAChRs in the regulation of intracellular bacterial infection.
Chemokine Receptor CCR2 Is Not Essential for the Development of Experimental Cerebral Malaria
Authors: Belnoue Elodie , Costa Fabio T. M. , Vigário Ana M. , Voza Tatiana , Gonnet Françoise , Landau Irène , van Rooijen Nico , Mack Matthias , Kuziel William A. , Rénia Laurent 
Published: May 2003

ABSTRACTInfection withPlasmodium bergheiANKA induces cerebral malaria in susceptible mice. Brain-sequestered CD8+T cells are responsible for this pathology. We have evaluated the role of CCR2, a chemokine receptor expressed on CD8+T cells. Infected CCR2-deficient mice were as susceptible to cerebral malaria as wild-type mice were, and CD8+T-cell migration to the brain was not abolished.
Actinobacillus actinomycetemcomitans
Serotype b Lipopolysaccharide Mediates Coaggregation with
Fusobacterium nucleatum
Authors: Rosen Graciela , Nisimov Ira , Helcer Monica , Sela Michael N. 
Published: May 2003

ABSTRACT

Purified
Actinobacillus actinomycetemcomitans
serotype b lipopolysaccharide (LPS) was found to be able to bind
Fusobacterium nucleatum
cells and to inhibit binding of
F. nucleatum
to
A. actinomycetemcomitans
serotype b. Sugar binding studies showed that the requirements for binding of
A. actinomycetemcomitans
serotype b LPS to the
F. nucleatum
lectin are the presence of a metal divalent ion, an axial free hydroxyl group at position 4, and free equatorial hydroxyl groups at positions 3 and 6 of
d
-galactose, indicating that the β-
N
-acetyl-
d
-galactosamine in the serotype b LPS trisaccharide repeating unit is the monosaccharide residue recognized by the
F. nucleatum
lectin. These data strongly suggest that
A. actinomycetemcomitans
serotype b LPS is one of the receptors responsible for the lactose-inhibitable coaggregation of
A. actinomycetemcomitans
to fusobacteria.
Physical Map and Genome Sequencing Survey ofMycoplasma haemofelis(Haemobartonella felis)
Authors: Berent Linda M. , Messick Joanne B. 
Published: May 2003

ABSTRACTMycoplasma haemofelisis an uncultivable red-cell pathogen of cats. IsolatedM. haemofelisDNA was used to create a bacterial artificial chromosome library and physical map. Random sequencing of this material revealed 75 genes that had not been previously reported forM. haemofelisor any other hemotrophic mycoplasma.
The Stereochemistry of the Amino Acid Side Chain Influences the Inflammatory Potential of Muramyl Dipeptide in Experimental Meningitis
Authors: Cottagnoud P. , Gerber C. M. , Majcherczyk P. A. , Acosta F. , Cottagnoud M. , Neftel K. , Moreillon P. , Täuber M. G. 
Published: May 2003

ABSTRACT

Intrathecal injections of 50 to 100 μg of (
N
-acetylmuramyl-
l
-alanyl-
d
-isoglutamine) muramyl dipeptide (MDP)/rabbit dose-dependently triggered tumor necrosis factor alpha (TNF-α) secretion (12 to 40,000 pg/ml) preceding the influx of leukocytes in the subarachnoid space of rabbits. Intrathecal instillation of heat-killed unencapsulated R6 pneumococci produced a comparable leukocyte influx but only a minimal level of preceding TNF-α secretion. The stereochemistry of the first amino acid (
l
-alanine) of the MDP played a crucial role with regard to its inflammatory potential. Isomers harboring
d
-alanine in first position did not induce TNF-α secretion and influx of leukocytes. This stereospecificity of MDPs was also confirmed by measuring TNF-α release from human peripheral mononuclear blood cells stimulated in vitro. These data show that the inflammatory potential of MDPs depends on the stereochemistry of the first amino acid of the peptide side chain and suggest that intact pneumococci and MDPs induce inflammation by different pathways.
Natural History of
Helicobacter hepaticus
Infection in Conventional A/J Mice, with Special Reference to Liver Involvement
Authors: Avenaud Philippe , Le Bail Brigitte , Mayo Kathryn , Marais Armelle , Fawaz Rabia , Bioulac-Sage Paulette , Megraud Francis 
Published: May 2003

ABSTRACT

It has been reported that
Helicobacter hepaticus
infection of mice leads to chronic hepatitis and hepatocarcinoma. Our aim was to monitor a cohort of 80 conventional A/J mice in which half of the mice were infected by
H
.
hepaticus
in order to study the evolution of the infection and the pathological changes in comparison to uninfected mice.
H
.
hepaticus
was detected by culture only in some colon and cecum specimens after 17 months of age, while PCR detected
H
.
hepaticus
in the intestines of all inoculated mice after only 5 months of infection. The percentage of mice in which
H
.
hepaticus
was detected in the gallbladder, bile ducts, and liver by PCR, as well as the number of bacteria present in the liver, tended to increase with increasing age and longer infection time. Anti-
H
.
hepaticus
immunoglobulin G antibodies were positive by enzyme-linked immunosorbent assay only in inoculated mice. Pathological findings were also more frequent as the mice grew older: fibrosis was present (especially in the peripheral part of the liver), and significant portal inflammation including lymphoid nodules was present in almost all infected animals. Biliary lesions of neutrophilic acute cholangitis or lymphocytic cholangitis were noted. However, lesions were also observed in uninfected animals, although at a significantly lower level, and the only hepatocellular carcinoma occurred in an uninfected mouse. The evolution towards hepatocarcinoma is not always the endpoint and may depend on the bacterial strain and on the environmental conditions.
DESITTER GAUGE THEORY OF GRAVITATION
Authors: ZET G. , MANTA V. , BABETI S. 
Published: May 2003

A deSitter gauge theory of gravitation over a spherical symmetric Minkowski space–time is developed. The "passive" point of view is adapted, i.e., the space–time coordinates are not affected by group transformations; only the fields change under the action of the symmetry group. A particular ansatz for the gauge fields is chosen and the components of the strength tensor are computed. An analytical solution of Schwarzschild–deSitter type is obtained in the case of null torsion. It is concluded that the deSitter group can be considered as a "passive" gauge symmetry for gravitation. Because of their complexity, all the calculations, inclusive of the integration of the field equations, are performed using an analytical program conceived in GRTensorII for MapleV. The program allows one to compute (without using a metric) the strength tensor [Formula: see text], Riemann tensor [Formula: see text], Ricci tensor [Formula: see text], curvature scalar [Formula: see text], field equations, and the integration of these equations.
INTRODUCTION TO THE NON-PERTURBATIVE RENORMALIZATION GROUP AND ITS RECENT APPLICATIONS
Authors: AOKI KEN-ICHI 
Published: May 2003

We introduce the basic ideas and the framework of the non-perturbative renormalization group particularly for pedestrians using elementary examples. First we briefly review the history of the renormalization theory and the renormalization group. We will make it clear that the modern renormalization theory is constructed on the idea of the renormalization group and it is quite a new type of theory in physics. Then we derive the exact non-perturbative renormalization group equation and set up its systematic approximation method. The lowest order approximation called the local potential approximation is applied to scalar theories with the ferromagnetic transition and quantum mechanics with tunneling. We compare our results with other methods, and will show that the non-perturbative renormalization group method is promising since it gives fairly good results already in the lowest order approximation and it does not suffer any divergent series expansion. As a typical application in high energy physics, we analyze the dynamical chiral symmetry breaking in gauge theories and investigate the chiral phase structures. Our new method improves results by the ladder Schwinger–Dyson equation so that the physical results might be less gauge dependent.
QCD — MOTIVATED QUARK STARS IN THE LIGHT OF RECENT ASTROPHYSICAL OBSERVATIONS
Authors: DEY MIRA , BOMBACI IGNAZIO , DEY JISHNU , RAY SUBHARTHI , VAN DEN HEUVEL E. P. J. , LI X.-D. 
Published: May 2003

Are there quark stars in nature? We review the question in the light of modern astrophysical observations. Quark stars have properties which are very similar to those of neutron stars. For example they are now known to have the same kind of cooling properties. Their masses may also be similar. On the other hand, gamma ray bursts (GRB), the brightest phenomenon observable at present in the sky, could possibly be conversion of normal or neutron matter on the surface of a quark star. The best observational evidence for the existence of quark stars seems to be some compact objects, the X-Ray burst source 4U 1820-30, the X-ray pulsar Her X-1, the star 4U 1728-34 and SAX J-1808.4-3658, this last one being the stablest and fastest rotating hard X-ray pulsar known to date. The mass of at least these four objects is high and their radius is low, placing them close to the black hole line, in the mass–radius (M–R) plot.
TRANSPORT IN LUTTINGER LIQUIDS
Authors: RAO SUMATHI 
Published: May 2003

We give a brief introduction to Luttinger liquids and to the phenomena of electronic transport or conductance in quantum wires. We explain why the subject of transport in Luttinger liquids is relevant and fascinating and review some important results on tunneling through barriers in a one-dimensional quantum wire and the phenomena of persistent currents in mesoscopic rings. We give a brief description of our own work on transport through doubly-crossed Luttinger liquids and transport in the Schulz–Shastry exactly solvable Luttinger-like model. With a view to making this article accessible to researchers in diverse fields such as nuclear physics, particle physics, formal field theory and condensed matter physics, we begin by first giving a brief introduction. In Sec. 1, we explain the words such as "Luttinger liquid" and "transport" in the title. We also motivate the study of this subject by showing that field is very important at the current time from the applications point of view and describe why it is theoretically fascinating. We then give a quick review of some of the important results in the field in Sec. 2, before we go on to describe some work that we have recently done and are doing in this field in Sec. 3. Finally, in Sec. 4, we conclude by re-emphasizing the importance of this area and drawing attention towards future possibilities.
CONFORMAL SUPERFIELDS AND BPS STATES IN AdS4/7 GEOMETRIES
Authors: FERRARA SERGIO , SOKATCHEV EMERY 
Published: May 2003

We carry out a general analysis of the representations of the superconformal algebras OSp(8/4, ℝ) and OSp(8*/2N) in terms of harmonic superspace. We present a construction of their highest-weight UIR's by multiplication of the different types of massless conformal superfields ("supersingletons"). Particular attention is paid to the so-called "short multiplets". Representations undergoing shortening have "protected dimension" and may correspond to BPS states in the dual supergravity theory in anti-de Sitter space. These results are relevant for the classification of multitrace operators in boundary conformally invariant theories as well as for the classification of AdS black holes preserving different fractions of supersymmetry.
SUPERCONDUCTING PROPERTIES OF LuNi2B2C THIN FILMS
Authors: GRASSANO G. , CIMBERLE M. R. , MARRÈ D. , PALLECCHI I. , PUTTI M. , RAMADAN W. , SIRI A. S. , FERDEGHINI C. , ANDREONE A. , CASSINESE A. , DI CAPUA R. , GIANNI L. , IAVARONE M. , MILETTO F. , RICCI F. , SCOTTI DI UCCIO U. , VAGLIO R. , CANEPA F. 
Published: May 2003

We present the results of collaboration between the groups of Naples and Genoa Universities/INFM, focused on thin films superconducting borocarbides. In particular a careful study of the deposition of non-magnetic LuNi 2 B 2 C thin films by Pulsed Laser Deposition (PLD) on MgO and other substrates will be presented. While samples with good c-orientation and superconducting properties are obtained in wide range of deposition parameters, in-plane micrometric oriented structures are obtained only in a narrow range of conditions, as evidenced by X-rays measurements and AFM (atomic force microscopy) analyses. A special set-up for the in situ interchanging of shadow masks has been developed in order to deposit the diferent patterned layers and different buffer and/or barrier layers. New results on the temperature dependence of the LuNi 2 B 2 C gap using S/N contact junctions are presented and discussed. The obtained value of the superconducting gap and its temperature dependence agrees very well with the BCS prediction. We present also microwave measurements of the surface impedance performed on large area films obtained by sputtering technique on low loss sapphire substrates. The data confirm the overall BCS-like behavior of these compounds.
RADIO FREQUENCY BEHAVIOUR OF PIT-PROCESSED BI(2223) TAPES
Authors: GRASSO G. , MALAGOLI A. , SCATI N. , GUASCONI P. , SIRI A. S. 
Published: May 2003

We have studied the response of long superconducting (Bi, Pb) 2 Sr 2 Ca 2 Cu 3 O 10 based conductors fabricated by the Oxide Powder In Tube method when exposed to a radio-frequency magnetic field excitation. In particular, we have characterized their properties when employed as a part L-C resonators typical of pick-up coil devices in Magnetic Resonance Imaging. In these conditions, Bi(2223) conductors cooled down to 77 K have shown superior properties compared to already optimized copper based devices: tri-dimensional superconducting pick-up coils conceived for a resonance frequency between 6 and 9 MHz present an improvement of the quality factor Q by more than an order of magnitude, and an increase of the signal-to-noise ratio by a factor larger than three. This promising result opens new perspectives for Bi-based conductors in the field of the detection of weak high frequency signals.
A NEW METALLIC NON MAGNETIC SUBSTRATE FOR COATED TAPE SUPERCONDUCTORS
Authors: GIUNCHI G. , CERESARA S. , CORTI R. , PETRISOR T. , MANCINI A. , CELENTANO G. 
Published: May 2003

The high Tc superconductors, realised in form of coated tapes, rely on the quality of the substrate on which they are growing. Furthermore the aim to produce a long superconducting tape, carrying the high engineering current densities typical of the power applications, push the search of a very robust and thin metallic tape as substrate. Looking for a trade off between the mechanical strength at high temperature and the chemical and structural compatibility of the substrate with the growing oxide superconductors, a new metallic alloy is proposed and a systems combining the metallic tape plus one micron thick textured oxide buffer layer is presented. The system fulfils also the demanding characteristics of a low manufacturing cost, being based on production technologies easily scalable at high volumes, like the melt flow casting of the metallic tape and the Electron Beam (EB) evaporation of the oxide film. The main physical characteristic of the new substrate, with the deposited buffer layer, are presented.