bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue-Specific Adherent
Enterococcus faecalis
Strains That Show Highly Efficient Adhesion to Human Bladder Carcinoma T24 Cells Also Adhere to Extracellular Matrix Proteins
Authors: Tomita Haruyoshi , Ike Yasuyoshi
Published: September 2004

The ability of
Enterococcus faecalis
clinical isolates to adhere to immobilized extracellular matrixes (ECMs) coating the walls of microtiter plates was examined by microscopy. The ECMs consisted of fibronectin, laminin, collagen types I, II, IV, and V, fibrinogen, and lactoferrin. With the exception of fibrinogen, each isolate showed a different level of adherence to each of the ECMs. No significant level of adherence to fibrinogen was observed for any isolate. The tissue-specific adhesive strains AS11, AS12, AS14, AS15, HT11, and HT12, which showed highly efficient adherence to human bladder carcinoma T24 cells and human bladder epithelial cells, showed strong adherence to fibronectin, laminin, and collagen type I, II, IV, and V ECMs, and the levels were greater than 10
4
cells/mm
2
of well surface coated by ECM. None of the isolates that showed little adherence to human bladder carcinoma T24 cells showed efficient adherence to all the ECMs. The levels of adherence of gelatinase-producing isolates to the collagens were lower than the levels of adherence of gelatinase-negative isolates. When tissue-specific adhesive strains that adhered strongly to each ECM were preincubated with fibronectin, the adherence of the strains to fibronectin was inhibited, but the adherence of the strains to collagen type IV was not inhibited. Likewise, preincubation with collagen type IV inhibited adherence to collagen type IV but not adherence to fibronectin. All of the
E. faecalis
isolates were shown to carry the
ace
gene by PCR analysis performed with specific primers for collagen binding domain A of
ace
. The
ace
gene encodes Ace (adhesin of collagen from enterococci). The
prtF
gene of group A streptococci, which encodes the fibronectin binding protein of group A streptococci, was not detected in the tissue-specific adhesive strains by Southern analysis performed with the
prtF
probe of the
Streptococcus pyogenes
JRS4 strain. Mutants with altered collagen binding were isolated by insertion of Tn
916
into the chromosome of tissue-specific adhesive strain AS14. The number of mutant adhesive bacterial cells that adhered to collagen and also to laminin was 1 or 2 orders lower than the number observed for the wild-type strain, but the level of adherence to fibronectin remained the same as that of the wild-type strain.
Invasion Profiles of Brazilian Field Isolates of
Plasmodium falciparum
: Phenotypic and Genotypic Analyses
Authors: Lobo Cheryl-Ann , de Frazao Karla , Rodriguez Marilis , Reid Marion , Zalis Mariano , Lustigman Sara
Published: September 2004

The invasion of red blood cells (RBCs) by
Plasmodium falciparum
is dependent on multiple molecular interactions between erythrocyte receptors and parasite ligands. Invasion studies using culture-adapted parasite strains have indicated significant receptor heterogeneity. It is not known whether this heterogeneity reflects the parasite invasion arsenal in the field. We have studied the invasion phenotypes of 14 distinct field isolates from the Legal Amazon areas of Brazil by using erythrocyte invasion assays to investigate invasion into normal, enzyme-treated, and clinical-mutant RBCs. Analysis of these isolates revealed four distinct invasion profiles. Using En(a−) cells to get an unequivocal estimate of the use of glycophorin A (GPA) as a receptor, we found that the 175-kDa erythrocyte-binding antigen (EBA-175)/GPA pathway was used by a minority of the parasite isolates studied. Although polymorphism of region II domains at specific amino acid positions in both EBA-140 and EBA-181 was found in these field isolates, this did not correlate with invasion profiles and thus receptor selectivity. These studies have further confirmed the existence of a significant diversity of invasion pathways in nature and suggest that additional parasite ligands will have to be targeted to devise global vaccines that will work in the field.
Naturally Acquired Passive Protective Activity against
Neisseria meningitidis
Group C in the Absence of Serum Bactericidal Activity
Authors: Welsch Jo Anne , Granoff Dan
Published: September 2004

The hallmark of immunity to meningococcal disease is a bactericidal titer in serum of ≥1:4 measured with human complement, but this threshold titer may underestimate the extent of protection. We used the infant rat model of meningococcal bacteremia to measure group C passive protective activity in serum samples from 91 unimmunized adults living in California. A total of 35 sera (38.5%) had passive protective activity. Sera with complement-mediated bactericidal titers of ≥1:4 were 3.4-fold more likely to confer protection (89%) than nonbactericidal sera (26%;
P
< 0.0001). Thus, bactericidal titers of ≥1:4 are a marker of protection, but this threshold lacks sensitivity for predicting protective activity. We investigated the 73 sera with bactericidal titers of <1:4 to determine the basis of protective activity. The 19 sera with protective activity had a higher geometric mean group C anticapsular antibody concentration (0.72 μg/ml) than the 54 sera that lacked protective activity (0.16 μg/ml;
P
< 0.001). Thus, protective activity in the absence of bactericidal activity was associated with higher concentrations of anticapsular antibodies, but not all sera with anticapsular antibodies conferred protection. Of 18 nonbactericidal sera with anticapsular antibody concentrations between 0.31 and 0.99 μg/ml, the 11 sera that conferred protection had a higher mean antibody avidity constant (21.9 nM
−1
) than the 7 nonprotective sera (14.6 nM
−1
;
P
< 0.03). Thus, in sera with titers of <1:4, protective activity is associated with higher-avidity group C anticapsular antibodies, which are present in concentrations insufficient to elicit complement-mediated bacteriolysis in vitro but sufficient to confer protection in an in vivo bacteremia model.
Porphyromonas gingivalisStrain-Dependent Activation of Human Endothelial Cells
Authors: Walter Clemens , Zahlten Janine , Schmeck Bernd , Schaudinn Christoph , Hippenstiel Stefan , Frisch Eckehard , Hocke Andreas C. , Pischon Nicole , Kuramitsu Howard K. , Bernimoulin Jean-Pierre , Suttorp Norbert , Krüll Matthias
Published: September 2004

Porphyromonas gingivalisis an important bacterium involved in periodontal diseases. Colonization by periodontopathogens has been associated with severe local inflammatory reactions in the connective tissue. In this study we characterizedP. gingivalis-mediated infection and activation of human umbilical vein endothelial cells by using two strains of different virulence capacities, strains ATCC 53977 and DSMZ 20709. Both strains were able to adhere to and infect endothelial cells with an infection rate of 0.48% for ATCC 53977 and 0.007% for DSMZ 20709. The triggering of two signal transduction pathways inP. gingivalis-infected endothelial cells was demonstrated for both strains, with a rapid increase of p38 mitogen-activated protein kinase phosphorylation and a more delayed degradation of IκBα, followed by nuclear translocation of NF-κB. In addition, both strains induced enhanced expression of endothelial adhesion molecules E-selectin and intracellular adhesion molecule 1 (ICAM-1). Target cell activation was independent of bacterial fimbriae expression since thefimAknockout strain A7436 ΔfimAinduced the same level of ICAM-1 as the corresponding wild type (A7436-WT). Thus, twoP. gingivalisstrains, ATCC 53799 and DSMZ 20709, infect endothelial cells and trigger signaling cascades leading to endothelial activation, which in turn may result in or promote severe local and systemic inflammation.
Strain-Dependent Role of BrkA duringBordetella pertussisInfection of the Murine Respiratory Tract
Authors: Elder Kelly D. , Harvill Eric T.
Published: September 2004

Bordetella pertussis, the causative agent of whooping cough, expresses many virulence factors believed to be involved in infection and disease progression. While these factors as a group are required for infection, deletion of individual virulence factor genes generally has limited effects on the ability ofB. pertussisto efficiently infect the respiratory tract of mice, suggesting they may perform noncritical or redundant functions. We have recently observed that aB. pertussisstrain, putatively with a mutation of a single gene,brkA, results in a severe defect in vivo. Although BrkA has been shown to be required forB. pertussisto resist complement-mediated killing in vitro, the relevance of these findings to the in vivo role of BrkA during infection has not been examined. Transducing this mutation into multiple wild-typeB. pertussisstrains allowed us to confirm the in vitro phenotype of reduced resistance to serum complement. All ΔbrkAmutants were increased in their sensitivity to complement in vitro, both in the presence and absence of antibodies. However, these strains differed substantially in their phenotypes in vivo. ΔbrkAmutants of recent clinical isolates were indistinguishable from wild-type strains in their efficient infection of respiratory organs, suggesting that the function of BrkA in these strains is noncritical or redundant. In contrast, multiple ΔbrkAstrains derived from Tohama I were severely defective during the first week postinoculation compared to their wild-type parent. This defect was present even in complement-deficient mice, revealing a complement-independent phenotype for the ΔbrkAmutant in respiratory tract infection.
Role of Cell-Cell Communication in Inhibiting Butyric Acid-Induced T-Cell Apoptosis
Authors: Kurita-Ochiai Tomoko , Seto Shintaro , Ochiai Kuniyasu
Published: September 2004

We have previously demonstrated that human gingival fibroblasts rescue butyric acid-induced T-cell apoptosis via proinflammatory cytokines such as interleukin 6 (IL-6) and IL-11, which are produced by fibroblasts stimulated with butyric acid. In this study, we determined if T-cell adhesion to human gingival fibroblasts influenced the susceptibility of T cells to butyric acid-induced apoptosis. We have shown that the number of Jurkat T cells adherent to gingival fibroblasts (Gin-1 cells) was significantly increased by the addition of butyric acid. All Jurkat cells that adhered to Gin-1 cells remained viable, while the nonadherent Jurkat cells dropped into apoptosis. The increase in T-cell adhesion to fibroblasts was also observed when Jurkat cells, but not Gin-1 cells, were pretreated with butyric acid. The expression levels of CD44, very late antigen 2 (VLA-2) and VLA-5 but not of leukocyte function-associated antigen 1 (LFA-1) and VLA-4 on Jurkat cells were increased following treatment with butyric acid. Furthermore, pretreatment of butyric acid-sensitized Jurkat cells with monoclonal antibodies against CD44, VLA-2, and VLA-5, but not LFA-1 and VLA-4, followed by coculture with Gin-1 cells inhibited T-cell adhesion to fibroblasts and increased apoptosis of nonadherent T cells after coculture of gingival fibroblasts and Jurkat cells. These results indicate that T-cell adherence to fibroblasts is enhanced by butyric acid and that butyric acid-induced T-cell apoptosis is down-regulated by T-cell adhesion to gingival fibroblasts through an interaction with the adhesion molecules CD44, VLA-2, and VLA-5 expressed on T cells stimulated with butyric acid.
IcmF and DotU Are Required for Optimal Effector Translocation and Trafficking of the
Legionella pneumophila
Vacuole
Authors: VanRheenen Susan M. , Duménil Guillaume , Isberg Ralph R.
Published: September 2004

The gram-negative bacterium
Legionella pneumophila
causes a severe form of pneumonia called Legionnaires' disease, characterized by bacterial replication within alveolar macrophages. Prior to intracellular replication, the vacuole harboring the bacterium must first escape trafficking to the host lysosome, a process that is dependent on the Dot/Icm type IV secretion system. To identify genes required for intracellular growth, bacterial mutants were isolated that were delayed in escape from the macrophage but which retain a minimally functional Dot/Icm machinery. The mutations were found in eight distinct genes, including three genes known to be required for optimal intracellular growth. Two of these genes,
icmF
and
dotU
, are located at one end of a cluster of genes that encode the type IV secretion system, yet both
icmF
and
dotU
lack orthologs in other type IV translocons. DotU protein is degraded in the early postexponential phase in wild-type
L. pneumophila
and at all growth phases in an
icmF
mutant. IcmF contains an extracytoplasmic domain(s) based on accessibility to a membrane-impermeant amine-reactive reagent. In the absence of either gene,
L. pneumophila
targets inappropriately to LAMP-1-positive compartments during macrophage infection, is defective in the formation of replicative vacuoles, and is impaired in the translocation of the effector protein SidC. Therefore, although IcmF and DotU do not appear to be part of the core type IV secretion system, these proteins are necessary for an efficiently functioning secretion apparatus.
Inhibition of Apoptosis byEscherichia coliK1 Is Accompanied by Increased Expression of BclXLand Blockade of Mitochondrial CytochromecRelease in Macrophages
Authors: Sukumaran Sunil K. , Selvaraj Suresh K. , Prasadarao Nemani V.
Published: September 2004

Escherichia coliK1 survival in the blood is a critical step for the onset of meningitis in neonates. Therefore, the circulating bacteria are impelled to avoid host defense mechanisms by finding a niche to survive and multiply. Our recent studies have shown thatE. coliK1 enters and survives in both monocytes and macrophages in the newborn rat model of meningitis as well as in macrophage cell lines. Here we demonstrate thatE. coliK1 not only extends the survival of human and murine infected macrophage cell lines but also renders them resistant to apoptosis induced by staurosporine. Macrophages infected with wild-typeE. coliexpressing outer membrane protein A (OmpA), but not with OmpA−E. coli, are resistant to DNA fragmentation and phosphatidylserine exposure induced by staurosporine. Infection with OmpA+E. coliinduces the expression of BclXL, an antiapoptotic protein, both at the mRNA level as assessed by gene array analysis and at the protein level as evaluated by immunoblotting. OmpA−E. coliinfection of macrophages induced the release of cytochromecfrom mitochondria into the cytosol and the activation of caspases 3, 6, and 9, events that were significantly blocked in OmpA+E. coli-infected macrophages. In addition, OmpA+E. coli-infected cells were resistant to a decrease in the transmembrane potential of mitochondria induced by staurosporine as measured by the MitoCapture fluorescence technique. Complementation of OmpA−E. coliwith a plasmid containing theompAgene restored the ability of OmpA−E. colito inhibit the apoptosis of infected macrophages, further demonstrating thatE. coliOmpA expression is critical for inducing macrophage survival and thereby finding a safe haven for its growth.
Development and Characterization of an In Vivo Central Venous Catheter
Candida albicans
Biofilm Model
Authors: Andes D. , Nett J. , Oschel P. , Albrecht R. , Marchillo K. , Pitula A.
Published: September 2004

Biofilms represent a niche for microorganisms where they are protected from both the host immune system and antimicrobial therapies. Biofilm growth serves as an increasing source of clinical infections.
Candida
infections are difficult to manage due to their persistent nature and associated drug resistance. Observations made in biofilm research have generally been limited to in vitro models. Using a rat central venous catheter model, we characterized in vivo
Candida albicans
biofilm development. Time-course quantitative culture demonstrated a progressive increase in the burden of viable cells for the first 24 h of development. Fluorescence and scanning electron microscopy revealed a bilayered architecture. Adjacent to the catheter surface, yeast cells were densely embedded in an extracellular matrix. The layer adjacent to the catheter lumen was less dense. The outermost surface of the biofilm contained both yeast and hyphal forms, and the extracellular material in which they were embedded appeared fibrous. These architectural features were similar in many respects to those described for in vitro models. However, scanning electron microscopy also revealed host cells embedded within the biofilm matrix. Drug susceptibility was determined by using two assays and demonstrated a biofilm-associated drug resistance phenotype. The first assay demonstrated continued growth of cells in the presence of supra-MIC antifungal drug concentrations. The second assay demonstrated reduced susceptibility of biofilm-grown cells following removal from the biofilm structure. Lastly, the model provided sufficient nucleic material for study of differential gene expression associated with in vivo biofilm growth. Two fluconazole efflux pumps,
CDR1
and
CDR2
, were upregulated in the in vivo biofilm-associated cells. Most importantly, the studies described provide a model for further investigation into the molecular mechanisms of
C. albicans
biofilm biology and drug resistance. In addition, the model provides a means to study novel drug therapies and device technologies targeted to the control of biofilm-associated infections.
Enterococcal Surface Protein, Esp, Enhances Biofilm Formation by
Enterococcus faecalis
Authors: Tendolkar Preeti M. , Baghdayan Arto S. , Gilmore Michael S. , Shankar Nathan
Published: September 2004

Enterococci play a dual role in human ecology. They serve as commensal organisms of the gastrointestinal tract and are also leading causes of multiple antibiotic-resistant hospital-acquired infection. Many nosocomial infections result from the ability of microorganisms to form biofilms. The molecular mechanisms involved in enterococcal biofilm formation are only now beginning to be understood. Enterococcal surface protein, Esp, has been reported to contribute to biofilm formation by
Enterococcus faecalis
. Recent studies have shown that enterococci form biofilms independently of Esp expression. To precisely determine what role Esp plays in
E. faecalis
biofilm formation, Esp was expressed on the cell surface of genetically well-defined, natively Esp-deficient strains, and isogenic Esp-positive and Esp-deficient strains were compared for their biofilm-forming ability. The results show that Esp expression leads to a significant increase in biofilm formation, irrespective of the strain tested. The contribution of Esp to biofilm formation was found to be most pronounced in the presence of 0.5% (wt/vol) or greater glucose. These results unambiguously define Esp as a key contributor to the ability of
E. faecalis
to form biofilms.
Bacterial Overgrowth in the Cystic Fibrosis Transmembrane Conductance Regulator Null Mouse Small Intestine
Authors: Norkina Oxana , Burnett Tim G. , De Lisle Robert C.
Published: September 2004

We recently reported the inflammation of the cystic fibrosis (CF) mouse small intestine, and we hypothesized bacterial overgrowth as a possible cause. Quantitative PCR of bacterial 16S genomic DNA in the CF mouse small intestine revealed an increase of greater than 40-fold compared to controls. Sequencing of 16S PCR products and Gram staining showed that the majority of bacteria in the CF mouse intestine were gram negative. Bacteria were observed to colonize the mucus that accumulates in the intestinal lumen of mice with CF. Impaired Paneth cell defenses were suggested by observation of partially dispersed Paneth granules in the mucus plugs of CF mouse intestinal crypts, and this mucus was strongly immunoreactive for Paneth cell bactericidal products. The role of bacterial overgrowth in intestinal inflammation in CF was tested by treating mice with oral antibiotics (ciprofloxacin and metronidazole) for 3 weeks, which reduced bacterial load in the CF mouse small intestine over 400-fold. Antibiotic treatment decreased the expression of the inflammation-related genes mast cell protease 2, leucine-rich α2 glycoprotein/leucine-rich high endothelial venule glycoprotein, suppressor of cytokine signaling 3, hematopoietic cell transcript 1, and resistin-like molecule β/found in inflammatory zone 2, all of which were no longer expressed at levels significantly different from control levels. The reduction of intestinal bacteria also significantly improved the growth of CF mice but had no effect on the growth of wild-type mice. These data suggest that bacterial overgrowth in the CF mouse small intestine has a role in inflammation and contributes to the failure to thrive in this mouse model of CF.
TheStreptococcus pyogenesCapsule Is Required for Adhesion of Bacteria to Virus-Infected Alveolar Epithelial Cells and Lethal Bacterial-Viral Superinfection
Authors: Okamoto Shigefumi , Kawabata Shigetada , Terao Yutaka , Fujitaka Hideaki , Okuno Yoshinobu , Hamada Shigeyuki
Published: September 2004

An apparent worldwide resurgence of invasive group AStreptococcus(GAS) infections remains unexplained. However, we recently demonstrated in mice that when an otherwise nonlethal intranasal GAS infection is preceded by a nonlethal influenza A virus (IAV) infection, induction of lethal invasive GAS infections is often the result. In the present study, we established several isogenic mutants from a GAS isolate and evaluated several virulence factors as candidates responsible for the induction of invasive GAS infections. Disruption of the synthesis of the capsule, Mga, streptolysin O, streptolysin S, or streptococcal pyrogenic exotoxin B of GAS significantly reduced mortality among mice superinfected with IAV and a mutant. In addition, the number of GAS organisms adhering to IAV-infected alveolar epithelial cells was markedly reduced with the capsule-depleted mutant, although this was not the case with the other mutants. Wild-type GAS was found to bind directly to IAV particles, whereas the nonencapsulated mutant showed much less ability to bind. These results suggest that the capsule plays a key role in the invasion of host tissues by GAS following superinfection with IAV and GAS.
Modulation of Airway Inflammation by Immunostimulatory CpG Oligodeoxynucleotides in a Murine Model of Allergic Aspergillosis
Authors: Banerjee Banani , Kelly Kevin J. , Fink Jordan N. , Henderson James D. , Bansal Naveen K. , Kurup Viswanath P.
Published: September 2004

Allergic aspergillosis is a Th2 T-lymphocyte-mediated pulmonary complication in patients with atopic asthma and cystic fibrosis. Therefore, any therapeutic strategy that selectively inhibits Th2 T-cell activation may be useful in downregulating allergic lung inflammation in asthma. In the present study, we developed a CpG oligodeoxynucleotide (ODN)-based immune intervention of allergic inflammation in a mouse model of allergic aspergillosis. Four different groups of mice were used in a short-term immunization protocol. Three experimental groups of animals (groups 1 to 3) were sensitized withAspergillus fumigatusantigens. Animals in group 1 were immunized withA. fumigatusantigen alone, while those in group 2 were treated with CpG-ODN 1 day before the first antigen immunization, and the animals in group 3 received the first CpG-ODN administration between the antigen treatments. The animals in group 4 served as controls and were given phosphate-buffered saline. Allergen-specific serum immunoglobulins and total immunoglobulin E in different groups of animals were measured by enzyme-linked immunosorbent assay, while airway remodeling and cytokine production were studied by immunohistochemistry. The results demonstrated that CpG-ODN administration either before (group 2) or between (group 3) antigen treatments resulted in reduced total immunoglobulin E levels and peripheral blood eosinophil numbers compared toA. fumigatusallergen-sensitized group 1 animals. Similarly, treatment with CpG-ODN also downregulated inflammatory cell infiltration, goblet cell hyperplasia, and basement membrane thickening compared toA. fumigatus-sensitized mice. The distinct reduction in peripheral blood eosinophilia and airway remodeling in CpG-ODN-treated mice emphasized its usefulness as an immunomodulating agent for allergic fungal diseases.
Biofilm Formation by
Neisseria meningitidis
Authors: Yi Kyungcheol , Rasmussen Andrew W. , Gudlavalleti Seshu K. , Stephens David S. , Stojiljkovic Igor
Published: September 2004

Biofilm formation by the human pathogen
Neisseria meningitidis
was analyzed. Biofilm-forming meningococcal strains were identified and quantitated by crystal violet staining. Laser scanning confocal microscopy of the meningococcal biofilm revealed variable layers up to 90 μm in thickness. A total of 39 meningococcal isolates were studied; 23 were nasopharyngeal-carriage isolates, and 16 were invasive-disease isolates. Thirty percent of carriage isolates and 12.5% of invasive-disease isolates formed biofilms proficiently on a polystyrene surface. Generally, the strains that formed biofilms showed high-level cell surface hydrophobicity, characteristic of strains lacking a capsule. The inhibitory role of capsule in biofilm formation was further confirmed by comparing the biofilm-forming capabilities of a serogroup B wild-type strain of a disease-associated isolate to those of its capsule-deficient mutant (
ctrA
). Some strains of meningococci form biofilms, and this process is likely important in menigococcal colonization.
Granuloma Necrosis during
Mycobacterium avium
Infection Does Not Require Tumor Necrosis Factor
Authors: Flórido Manuela , Appelberg Rui
Published: September 2004

The infection of tumor necrosis factor (TNF)-deficient mice with low doses of the virulent
Mycobacterium avium
strain 25291 led to the appearance of necrotic granulomas at 93 days of infection, i.e., sooner than necrotic granulomas appeared in C57BL/6 animals. Additionally, TNF-deficient mice exhibited higher mycobacterial loads in the infected organs, had extremely exacerbated gamma interferon responses as evaluated in the sera of infected animals, and showed reduced survival. Thus, TNF is not required for granuloma necrosis.
Persistence of
Burkholderia multivorans
within the Pulmonary Macrophage in the Murine Lung
Authors: Chu Karen K. , MacDonald Kelly L. , Davidson Donald J. , Speert David P.
Published: September 2004

Differences in infection kinetics and host response between
Burkholderia multivorans
and
Burkholderia cenocepacia
were demonstrated in a pulmonary infection model in BALB/c mice.
B. multivorans
persisted in the lung, while
B. cenocepacia
was cleared. Indirect immunofluorescence and electron microscopy of
B. multivorans
-infected lungs localized bacteria to macrophages. Clearance of
B. cenocepacia
was associated with greater interleukin-1β and neutrophil responses than the responses induced by
B. multivorans
.
Protective Effect of a Tuberculosis Subunit Vaccine Based on a Fusion of Antigen 85B and ESAT-6 in the Aerosol Guinea Pig Model
Authors: Olsen Anja W. , Williams Ann , Okkels Limei M. , Hatch Graham , Andersen Peter
Published: September 2004

A fusion protein of antigen 85B (Ag85B) and ESAT-6 administered in cationic lipid vesicles conferred a highly significant level of protection against
Mycobacterium tuberculosis
in the guinea pig aerosol model of infection. The protection was manifested as delayed clinical illness and prolonged survival. Neither Ag85B nor ESAT-6 (independently or as a cocktail) induced significant protection in this model.
Use of Deoxyribose by Intestinal and Extraintestinal Pathogenic
Escherichia coli
Strains: a Metabolic Adaptation Involved in Competitiveness
Authors: Bernier-Fébreau Christine , du Merle Laurence , Turlin Evelyne , Labas Valérie , Ordonez Juana , Gilles Anne-Marie , Le Bouguénec Chantal
Published: September 2004

We showed that the
deoK
operon, which confers the ability to use deoxyribose as a carbon source, is more common among pathogenic than commensal
Escherichia coli
strains. The expression of the
deoK
operon increases the competitiveness of clinical isolates, suggesting that this biochemical characteristic plays a role in host infectivity.
Binding of Pro-Matrix Metalloproteinase 9 byFusobacterium nucleatumsubsp.nucleatumas a Mechanism To Promote the Invasion of a Reconstituted Basement Membrane
Authors: Gendron Renée , Plamondon Pascale , Grenier Daniel
Published: September 2004

In this study, we investigated the ability ofFusobacterium nucleatumsubsp.nucleatumto increase its tissue-invasive potential by acquiring cell-associated human matrix metalloproteinase 9 (MMP-9) activity. Binding of pro-MMP-9 to fusobacteria was demonstrated by enzyme-linked immunosorbent assay. Zymography and a colorimetric assay showed that bound pro-MMP-9 can be converted into a proteolytically active form. The potential contribution of this acquired host activity in tissue invasion was demonstrated using a reconstituted basement membrane (Matrigel).
Long Polar Fimbriae Contribute to Colonization by
Escherichia coli
O157:H7 In Vivo
Authors: Jordan Dianna M. , Cornick Nancy , Torres Alfredo G. , Dean-Nystrom Evelyn A. , Kaper James B. , Moon Harley W.
Published: September 2004

The contribution of long polar fimbriae to intestinal colonization by
Escherichia coli
O157:H7 was evaluated in sheep, conventional pigs, and gnotobiotic piglets.
E. coli
O157:H7 strains with
lpfA1
and
lpfA2
mutated were recovered in significantly lower numbers and caused fewer attachment and effacement lesions than the parent strain.
Oral Immunization with a Combination ofPlasmodium yoeliiMerozoite Surface Proteins 1 and 4/5 Enhances Protection against Lethal Malaria Challenge
Authors: Wang Lina , Goschnick Matthew W. , Coppel Ross L.
Published: September 2004

Oral immunization of mice withEscherichia coli-expressedPlasmodium yoeliimerozoite surface protein 4/5 or the C-terminal 19-kDa fragment of merozoite surface protein 1 induced systemic antibody responses and protected mice against lethal malaria infection. A combination of these two proteins administered orally conferred improved protection compared to that conferred by either protein administered alone.
A Peptide Domain of Bovine Milk Lactoferrin Inhibits the Interaction between Streptococcal Surface Protein Antigen and a Salivary Agglutinin Peptide Domain
Authors: Oho Takahiko , Bikker Floris J. , Nieuw Amerongen Arie V. , Groenink Jasper
Published: September 2004

The peptide domain of salivary agglutinin responsible for its interaction with cell surface protein antigen (PAc) of
Streptococcus mutans
or bovine lactoferrin was found in the same peptide, scavenger receptor cysteine-rich domain peptide 2 (SRCRP2). Inhibition studies suggest that PAc and lactoferrin, of which residues 480 to 492 seem important, competitively bind to the SRCRP2 domain of salivary agglutinin.
QUASITRIANGULAR WZW MODEL
Authors: KLIMČÍK CTIRAD
Published: September 2004

A dynamical system is canonically associated to every Drinfeld double of any affine Kac–Moody group. In particular, the choice of the affine Lu–Weinstein double gives a smooth one-parameter deformation of the standard WZW model. The deformed WZW model is exactly solvable and it admits the chiral decomposition. Its classical action is not invariant with respect to the left and right action of the loop group, however, it satisfies the weaker condition of the Poisson–Lie symmetry. The structure of the deformed WZW theory is characterized by several ordinary and dynamical r-matrices with spectral parameter. They describe the q-deformed current algebras, appear in the definition of q-primary fields and characterize the quasitriangular exchange (braiding) relations. The symplectic structure of the deformed chiral WZW theory is cocharacterized by the same elliptic dynamical r-matrix that appears in the Bernard generalization of the Knizhnik–Zamolodchikov equation, with q entering the modular parameter of the Jacobi theta functions. This reveals a remarkable connection between the classical q-deformed WZW model and the quantum standard WZW theory on elliptic curves.
CONTINUITY OF A CLASS OF ENTROPIES AND RELATIVE ENTROPIES
Authors: NAUDTS JAN
Published: September 2004

The present paper studies continuity of generalized entropy functions and relative entropies defined using the notion of a deformed logarithmic function. In particular, two distinct definitions of relative entropy are discussed. As an application, all considered entropies are shown to satisfy Lesche's stability condition. The entropies of Tsallis' non-extensive thermostatistics are taken as examples.
SELF-SIMILAR SPACE-FILLING PACKINGS IN THREE DIMENSIONS
Authors: BARAM REZA MAHMOODI , HERRMANN HANS J.
Published: September 2004

We develop an algorithm to construct new self-similar space-filling packings of spheres. Each topologically different configuration is characterized by its own fractal dimension. We also find the first bichromatic packing known up to now.
CHARACTERIZING DYNAMIC SPECKLE TIME SERIES WITH THE HURST COEFFICIENT CONCEPT
Authors: PASSONI L. I. , RABAL H. , ARIZMENDI C. M.
Published: September 2004

We propose in this work a dynamic speckle descriptor based on a Hurst wavelet estimator. The dynamic speckle or biospeckle is a phenomenon produced by laser illumination of active materials, such as biological tissue or the drying process of paint. Dynamic speckle interferometry is a useful technique for assessing the time evolution of surfaces as also to segment the loci of different activity in living tissues. Considering previous biospeckle characterization based on the autocorrelation function and its relation with the Hurst coefficient, a wavelet-based estimator is proposed as a feature extraction of the dynamic speckle characteristic. Encouraging results of the descriptor performance are obtained via three different experiments: a time history of speckle pattern applied to the drying of painting, segmenting regions in whole field image applied to the viability test of a corn seed and also to the bruising in fruits.
UNIVERSALITY ASPECTS OF SELF-ORGANIZATION MODELS
Authors: MALAKIS A. , DIAKONOS F. K.
Published: September 2004

A sandpile model on the square lattice with periodic boundary conditions is studied as a problem of variable density of grains per site. We define an order parameter and we show the existence of a critical density. This model is the closed version of the deterministic BTW model and belongs to the "Fixed Energy Sandpiles" class. An algorithm identifying the periodic states of the system permits us to have a good estimation of the order parameter, which is free from transient effects. The universality of the model with respect to two different forms of oriented flows is studied and compared with that of the isotropic flow. We find two universality classes characterized by different critical exponents. The Manhattan flow appears to belong to the same universality class as the isotropic flow. However, the directed flow gives a completely different critical behavior. The complexity of the model for densities larger than the critical is also studied. It is observed that, both the Manhattan model and the isotropic model have an interesting structure characterized by several plateaus. The right edges of these plateaus are characterized by a sudden increase of the order parameter, giving rise to new critical points. The directed flow model has a simple structure without plateaus.
A NEW DISTRIBUTION-BASED TEST OF SELF-SIMILARITY
Authors: BIANCHI SERGIO
Published: September 2004

In studying the scale invariance of an empirical time series a twofold problem arises: it is necessary to test the series for self-similarity and, once passed such a test, the goal becomes to estimate the parameter H0of self-similarity. The estimation is therefore correct only if the sequence is truly self-similar but in general this is just assumed and not tested in advance. In this paper we suggest a solution for this problem. Given the process {X(t),t∈T}, we propose a new test based on the diameter δ of the space of the rescaled probability distribution functions of X(t). Two necessary conditions are deduced which contribute to discriminate self-similar processes and a closed formula is provided for the diameter of the fractional Brownian motion (fBm). Furthermore, by properly choosing the distance function, we reduce the measure of self-similarity to the Smirnov statistics when the one-dimensional distributions of X(t) are considered. This permits the application of the well-known two-sided test due to Kolmogorov and Smirnov in order to evaluate the statistical significance of the diameter δ, even in the case of strongly dependent sequences. As a consequence, our approach both tests the series for self-similarity and provides an estimate of the self-similarity parameter.
MULTIFRACTALITY IN AN ELECTROCHEMICAL NOISE SIGNAL BY A BIOCORROSION SYSTEM
Authors: AMAYA M. , SOSA E. , ROMERO J. M. , ALVAREZ-RAMIREZ J. , MERAZ M. , PUEBLA H.
Published: September 2004

An analysis of multifractal characteristics of the potential time series of electrochemical noise generated during surface corrosion is performed. The generalized Hurst exponent, called Hq, is computed for potential fluctuations induced for steel corroding by a sulphate reducing bacterial consortia. The results indicate evidence of multifractal behavior in the sense that the qth-order (roughness) Hurst exponent Hqvaries with changes in q. This multifractal structure is corroborated by means of microscopy inspection of the corroded surface.
MULTISCALE TREND ANALYSIS
Authors: ZALIAPIN ILYA , GABRIELOV ANDREI , KEILIS-BOROK VLADIMIR
Published: September 2004

This paper introduces a multiscale analysis based on optimal piecewise linear approximations of time series. An optimality criterion is formulated, and on its base, a computationally effective algorithm is constructed for decomposition of a time series into a hierarchy of trends (local linear approximations) at different scales. The top of the hierarchy is the global linear approximation over the whole observational interval, the bottom is the original time series. Each internal level of the hierarchy corresponds to a piecewise linear approximation of analyzed series. Possible applications of the introduced Multiscale Trend Analysis (MTA) go far beyond the linear interpolation problem: This paper develops and illustrates methods of self-affine, hierarchical, and correlation analyses of time series.
INTERVAL METHODS IN KNOWLEDGE REPRESENTATION
Authors: KREINOVICH VLADIK
Published: September 2004

This section is maintained by Vladik Kreinovich. Please send you abstract (or copies of papers that you want to see reviewed here) to vladik@cs.utep.edu, or by regular mail to: Vladik Kreinovich, Department of Computer Science, University of Texas at El Paso, El Paso, TX 79968, USA.
FUZZY GRAMMAR FOR HANDLING FUZZY ALGORITHMS
Authors: CASTRO J. L. , DELGADO M. , MANTAS C. J.
Published: September 2004

This paper presents a new procedure for handling fuzzy algorithm. It consists of transforming the steps of a fuzzy algorithm into production rules of a fuzzy grammar, executing it using the dynamic of this grammar and adjusting its execution by means of the learning capability of the fuzzy formal languages. With this method, some flexible criterial about the goodness of the execution of a fuzzy algorithm are only necessary for adjusting it. Finally, this procedure is applied for executing and adjusting a fuzzy rule-based system.
Abundance of two human preadipocyte subtypes with distinct capacities for replication, adipogenesis, and apoptosis varies among fat depots
Authors: Tchkonia Tamara , Tchoukalova Yourka D. , Giorgadze Nino , Pirtskhalava Tamar , Karagiannides Iordanes , Forse R. Armour , Koo Ada , Stevenson Michael , Chinnappan Dharmaraj , Cartwright Andrew , Jensen Michael D. , Kirkland James L.
Published: September 2004

Fat depots vary in function and size. The preadipocytes that fat cells develop from exhibit distinct regional characteristics that persist in culture. Human abdominal subcutaneous cultured preadipocytes undergo more extensive lipid accumulation, higher adipogenic transcription factor expression, and less TNF-α-induced apoptosis than omental preadipocytes. We found higher replicative potential in subcutaneous and mesenteric than in omental preadipocytes. In studies of colonies arising from single preadipocytes, two preadipocyte subtypes were found, one capable of more extensive replication, differentiation, and adipogenic transcription factor expression and less apoptosis in response to TNF-α than the other. The former was more abundant in subcutaneous and mesenteric than in omental preadipocyte populations, potentially contributing to regional variation in replication, differentiation, and apoptosis. Both subtypes were found in strains derived from single human preadipocytes stably expressing telomerase, confirming that both subtypes are of preadipocyte lineage. After subcloning of cells of either subtype, both subtypes were found, indicating that switching can occur between subtypes. Thus proportions of preadipocyte subtypes with distinct cell-dynamic properties vary among depots, potentially permitting tissue plasticity through subtype selection during development. Furthermore, mesenteric preadipocyte cell-dynamic characteristics are distinct from omental cells, indicating that visceral fat depots are not functionally uniform.
Malonyl-CoA and carnitine in regulation of fat oxidation in human skeletal muscle during exercise
Authors: Roepstorff Carsten , Halberg Nils , Hillig Thore , Saha Asish K. , Ruderman Neil B. , Wojtaszewski Jørgen F. P. , Richter Erik A. , Kiens Bente
Published: September 2004

Intracellular mechanisms regulating fat oxidation were investigated in human skeletal muscle during exercise. Eight young, healthy, moderately trained men performed bicycle exercise (60 min, 65% peak O2consumption) on two occasions, where they ingested either 1) a high-carbohydrate diet (H-CHO) or 2) a low-carbohydrate diet (L-CHO) before exercise to alter muscle glycogen content as well as to induce, respectively, low and high rates of fat oxidation. Leg fat oxidation was 122% higher during exercise in L-CHO than in H-CHO ( P < 0.001). In keeping with this, the activity of α2-AMP-activated protein kinase (α2-AMPK) was increased twice as much in L-CHO as in H-CHO ( P < 0.01) at 60 min of exercise. However, acetyl-CoA carboxylase (ACC)β Ser221phosphorylation was increased to the same extent (6-fold) under the two conditions. The concentration of malonyl-CoA was reduced 13% by exercise in both conditions ( P < 0.05). Pyruvate dehydrogenase activity was higher during exercise in H-CHO than in L-CHO ( P < 0.01). In H-CHO only, the concentrations of acetyl-CoA and acetylcarnitine were increased ( P < 0.001), and the concentration of free carnitine was decreased ( P < 0.01), by exercise. The data suggest that a decrease in the concentration of malonyl-CoA, secondary to α2-AMPK activation and ACC inhibition (by phosphorylation), contributes to the increase in fat oxidation observed at the onset of exercise regardless of muscle glycogen levels. They also suggest that, with high muscle glycogen, the availability of free carnitine may limit fat oxidation during exercise, due to its increased use for acetylcarnitine formation.
Synthesis of the Na-K-ATPase γ-subunit is regulated at both the transcriptional and translational levels in IMCD3 cells
Authors: Capasso Juan M. , Rivard Christopher J. , Berl Tomas
Published: September 2004

We previously reported that hypertonicity-mediated upregulation of the γ-subunit of Na-K-ATPase is dependent on both the JNK and the PI3 kinase pathways ( Proc Natl Acad Sci USA 98: 13414, 2001). The present experiments were undertaken to explore the mechanisms whereby these pathways regulate the expression of the γ-subunit in inner medullary collecting duct cells (IMCD3). Inhibition of JNK with SP-600125 (20 μM), a concentration that causes an ∼95% inhibition of hypertonicity-stimulated JNK activation, markedly decreased the amount of the γ-subunit in response to 550 mosmol/kgH2O for 48 h. This was accompanied by a parallel decrease in the γ-subunit mRNA. The rate at which the γ-subunit mRNA decreased was unaffected by actinomycin D. In contrast, inhibition of PI3 kinase with LY-294002 results in a marked decrease in the amount of γ-subunit protein but without alteration in γ-subunit message. The rate at which the γ-subunit protein decreased was unaffected by cyclohexamide. Transfection of IMCD3 cells with a γ-subunit construct results in the expression of both γ-subunit message and protein. However, in cortical collecting duct cells (M1 cells) such transfection resulted in expression of only the message and not the protein. We conclude that JNK regulates the γ-subunit at the transcriptional level while PI3 kinase regulates γ-subunit expression at the translational level. There is also posttranscriptional cell specificity in the expression of the γ -subunit of Na-K-ATPase.
Posttranslational regulation of NO synthase activity in the renal medulla of diabetic rats
Authors: Lee Dexter L. , Sasser Jennifer M. , Hobbs Janet L. , Boriskie Amy , Pollock David M. , Carmines Pamela K. , Pollock Jennifer S.
Published: September 2004

Shear stress increases nitric oxide (NO) production by endothelial cells, inner medullary collecting duct cells, and thick ascending limb. We postulated that the osmotic diuresis accompanying type 1 diabetes is associated with increased NO synthase (NOS) activity and/or expression in the renal medulla. Diabetes was induced by injection of streptozotocin, with insulin provided to maintain moderate hyperglycemia (Hyp) or euglycemia (Eug) for 3 wk. Sham rats received vehicle treatments. A separate group of rats (Phz) received phlorizin to produce a glucose-dependent osmotic diuresis. Renal medullary NOS1 and NOS2 activities did not differ between groups, whereas NOS3 activity was significantly increased in Hyp. Neither NOS1 nor NOS3 protein levels differed significantly between groups. Reduced phosphorylation of NOS3 at Thr495and Ser633was evident in medullary homogenates from Hyp rats, with no difference apparent at Ser1177. Immunohistochemical analysis indicated prominent expression of pThr495NOS3 in the thick ascending limb and collecting duct of Sham and Phz rats. Hyp rats displayed staining in the collecting duct but minimal thick ascending limb staining. Immunostaining with anti-pSer1177NOS3 was evident only in the thick ascending limb, with no apparent differences between groups. In summary, glucose-dependent osmotic diuresis alone did not alter NOS activity or expression in the renal medulla. Diabetic hyperglycemia increased medullary NOS3 activity without a concomitant increase in NOS3 protein levels; however, NOS3 phosphorylation was reduced at Thr495and Ser633. Thus changes in the phosphorylation of NOS at known regulatory sites might represent the primary mechanism underlying increased renal medullary NOS activity in diabetic hyperglycemia.