bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cellular Localization of
Babesia bovis
Merozoite Rhoptry-Associated Protein 1 and Its Erythrocyte-Binding Activity
Authors: Yokoyama Naoaki , Suthisak Boonchit , Hirata Haruyuki , Matsuo Tomohide , Inoue Noboru , Sugimoto Chihiro , Igarashi Ikuo 
Published: September 2002

ABSTRACT

The cellular localization of
Babesia bovis
rhoptry-associated protein 1 (RAP-1) and its erythrocyte-binding affinity were examined with anti-RAP-1 antibodies. In an indirect immunofluorescent antibody test, RAP-1 was detectable in all developmental stages of merozoites and in extracellular merozoites. In the early stage of merozoite development, RAP-1 appears as a dense accumulation, which later thins out and blankets the host cell cytoplasm, but retains a denser mass around newly formed parasite nuclei. The preferential accumulations of RAP-1 on the inner surface of a host cell membrane and bordering the parasite's outer surface were demonstrable by immunoelectron microscopy. An erythrocyte-binding assay with the lysate of merozoites demonstrated RAP-1 binding to both bovine and equine erythrocytes. Anti-RAP-1 monoclonal antibody 1C1 prevented the interaction of RAP-1 with bovine erythrocytes and significantly inhibited parasite proliferation in vitro. With the recombinant RAP-1, the addition of increasing concentrations of Ca
2+
accentuated its binding affinity with bovine erythrocytes. The present findings lend support to an earlier proposition of an erythrocytic binding role for RAP-1 expressed in
B. bovis
merozoites and, possibly, its involvement in the escape of newly formed merozoites from host cells.
Isolation of
Chlamydia pneumoniae
Clonal Variants by a Focus-Forming Assay
Authors: Gieffers Jens , Belland Robert J. , Whitmire William , Ouellette Scot , Crane Deborah , Maass Matthias , Byrne Gerald I. , Caldwell Harlan D. 
Published: September 2002

ABSTRACT

Chlamydia pneumoniae
is an obligate intracellular prokaryotic human pathogen that causes community-acquired respiratory infection and has been associated with atherosclerosis and cardiovascular disease. Unexpected results from genomic sequencing indicate that significant intrastrain polymorphism exists for some
C. pneumoniae
isolates. These polymorphisms could reflect genotypes with differing disease-causing characteristics. A definitive means to test this hypothesis is to obtain genetically homogeneous clonal populations of the pathogen and test them in models of infection and disease. To date, methods for cloning
C. pneumoniae
have not been reported. In this study, we describe the isolation of clonal variants with genetic differences in the
tyrP
locus from a polymorphic respiratory isolate, using a novel focus-forming assay. These results now allow investigations on the biology and pathogenesis of
C. pneumoniae
clonal genovars that could lead to new insights into the pathogenesis of this important human pathogen.
Identification of theStaphylococcus aureus etdPathogenicity Island Which Encodes a Novel Exfoliative Toxin, ETD, and EDIN-B
Authors: Yamaguchi Takayuki , Nishifuji Koji , Sasaki Megumi , Fudaba Yasuyuki , Aepfelbacher Martin , Takata Takashi , Ohara Masaru , Komatsuzawa Hitoshi , Amagai Masayuki , Sugai Motoyuki 
Published: September 2002

ABSTRACTWe identified a novel pathogenicity island inStaphylococcus aureuswhich contains open reading frames (ORFs) similar to the exfoliative toxin (ET) gene, glutamyl endopeptidase gene, andedin-Bgene in tandem and the phage resistance gene, flanked byhsdM,hsdS(restriction and modification system), and IS256. The protein encoded by the ET-like gene showed 40, 59, and 68% amino acid sequence identities with exfoliative toxin A (ETA), exfoliative toxin B (ETB), andStaphylococcus hyicusETB (ShETB), respectively. When injected into neonatal mice, the recombinant protein derived from the ET-like gene induced exfoliation of the skin with loss of cell-to-cell adhesion in the upper part of the epidermis as observed in histological examinations, just as was found in neonatal mice injected with ETA or ETB. Western blot analysis indicated that the recombinant protein is serologically distinct from ETA and ETB. Therefore, the product encoded by this new ORF is a new ET member produced byS. aureusand is termed ETD. ETD did not induce blisters in 1-day-old chickens. In the skins of mice injected with ETD, cell surface staining of desmoglein 1 (Dsg1), a cadherin type cell-to-cell adhesion molecule in desmosomes, was abolished without affecting that of desmoglein 3 (Dsg3). Furthermore, in vitro incubation of the recombinant extracellular domains of Dsg1 and Dsg3 with the recombinant protein demonstrated that both mouse and human Dsg1, but not Dsg3, were directly cleaved in a dose-dependent manner. These results demonstrate that ETD and ETA induce blister formation by identical pathophysiological mechanisms. Clinical strains positive foredin-Bwere suggested to be clonally associated, and alledin-B-positive strains tested were positive foretd. Among 18etd-positive strains, 12 produced ETD extracellularly. Interestingly, these strains are mainly isolated from other sources of infections and not from patients with bullous impetigo or staphylococcal scalded-skin syndrome. This strongly suggests that ETD might play a pathogenic role in a broader spectrum of bacterial infections than previously considered.
Discrete Proteolysis of Focal Contact and Adherens Junction Components in
Porphyromonas gingivalis-
Infected Oral Keratinocytes: a Strategy for Cell Adhesion and Migration Disabling
Authors: Hintermann Edith , Haake Susan Kinder , Christen Urs , Sharabi Andrew , Quaranta Vito 
Published: September 2002

ABSTRACT

Adhesive interactions of cells are critical to tissue integrity. We show that infection with
Porphyromonas gingivalis
, a major pathogen in the periodontal disease periodontitis, interferes with both cell-matrix and cell-cell adhesion in the oral keratinocyte cell line HOK-16. Thus, infected cells showed reduced adhesion to extracellular matrix, changes in morphology from spread to rounded, and impaired motility on purified matrices in Transwell migration assays and scratch assays. Western blot analysis of
P. gingivalis
-challenged HOK-16 cells revealed proteolysis of focal contact components (e.g., focal adhesion kinase), adherens junction proteins (e.g., catenins), and adhesion signaling molecules (e.g., the tyrosine kinase SRC). Proteolysis was selective, since important components of adherens junctions (E-cadherin) or signaling molecules (extracellular signal-regulated kinases ERK1/2) were not degraded. The virulence factors gingipains, cysteine proteinases expressed by
P. gingivalis
, are likely responsible for this proteolytic attack, since they directly digested specific proteins in pull-down experiments, and their proteolytic activity was blocked by the cysteine proteinase inhibitor
N-
α-
p
-tosyl-
l
-lysine chloromethyl ketone and also by a caspase inhibitor. Proteolysis was strain dependent, such that ATCC 33277 and 381 had high proteolytic potential, whereas W50 showed almost no proteolytic activity. These findings may help explain the formation of gingival pockets between cementum and periodontal epithelium, a hallmark of periodontitis. Furthermore, they illustrate a new pathogenetic paradigm of infection whereby bacteria may disrupt the integrity of epithelia.
Requirement for Tumor Necrosis Factor Receptor 2 Expression on Vascular Cells To Induce Experimental Cerebral Malaria
Authors: Stoelcker Benjamin , Hehlgans Thomas , Weigl Karin , Bluethmann Horst , Grau Georges E. , Männel Daniela N. 
Published: September 2002

ABSTRACTUsing tumor necrosis factor receptor type 2 (TNFR2)-deficient mice and generating bone marrow chimeras which express TNFR2 on either hematopoietic or nonhematopoietic cells, we demonstrated the requirement for TNFR2 expression on tissue cells to induce lethal cerebral malaria. Thus, TNFR2 on the brain vasculature mediates tumor necrosis factor-induced neurovascular lesions in experimental cerebral malaria.
Chlamydial Antigens Colocalize within IncA-Laden Fibers Extending from the Inclusion Membrane into the Host Cytosol
Authors: Brown W. J. , Skeiky Y. A. W. , Probst P. , Rockey D. D. 
Published: September 2002

ABSTRACTChlamydial IncA localizes to the inclusion membrane and to vesicular fibers extending away from the inclusion. Chlamydial outer membrane components, in the absence of developmental forms, are found within these fibers. This colocalization may explain how chlamydial developmental form antigens are localized outside of the inclusion within infected cells.
A Uropathogenicity Island Contributes to the Pathogenicity of
Escherichia coli
Strains That Cause Neonatal Meningitis
Authors: Houdouin Véronique , Bonacorsi Stéphane , Brahimi Naima , Clermont Olivier , Nassif Xavier , Bingen Edouard 
Published: September 2002

ABSTRACT

We report that the archetypal
Escherichia coli
strain C5 causing neonatal meningitis harbors a pathogenicity island (PAI) designated PAI I
C5
that is similar to the PAI II
J96
of uropathogenic
E. coli
J96 inserted in the
leuX-
tRNA gene. PAI-negative C5 mutants had a lower capacity than C5 to induce high-level bacteremia in a neonatal rat model. However, no change in their resistance to the bactericidal effect of serum and their capacity to cross the blood-brain barrier was observed.
Macrophage-Enhanced Germination of
Bacillus anthracis
Endospores Requires
gerS
Authors: Ireland John A. W. , Hanna Philip C. 
Published: September 2002

ABSTRACT

Germination of
Bacillus anthracis
Sterne and plasmidless Δ-Sterne endospores was dramatically enhanced in RAW264.7 macrophage-like cells, while germination of nonpathogenic
Bacillus
endospores was not. Elimination of
gerS
, a germinant receptor locus, caused a complete loss of cell-enhanced germination, implicating
gerS
in the breaking of endospore dormancy in vivo.
A Monoclonal Antibody to the Amebic Lipophosphoglycan-Proteophosphoglycan Antigens Can Prevent Disease in Human Intestinal Xenografts Infected with
Entamoeba histolytica
Authors: Zhang Zhi , Duchêne Michael , Stanley Samuel L. 
Published: September 2002

ABSTRACT

Entamoeba histolytica
trophozoites are covered by lipophosphoglycan-peptidoglycan molecules which may be key virulence factors. We found that pretreatment of severe combined immunodeficient mice bearing human intestinal xenografts with a monoclonal antibody to the amebic lipophosphoglycan-peptidoglycan molecules can prevent or significantly reduce the human intestinal inflammation and tissue damage that are normally seen with
E. histolytica
colonic infection.
Two Predicted Chemoreceptors of
Helicobacter pylori
Promote Stomach Infection
Authors: Andermann Tessa M. , Chen Yu-Ting , Ottemann Karen M. 
Published: September 2002

ABSTRACT

Helicobacter pylori
must be motile or display chemotaxis to be able to fully infect mammals, but it is not known how this chemotaxis is directed. We disrupted two genes encoding predicted chemoreceptors,
tlpA
and
tlpC. H. pylori
mutants lacking either of these genes are fully motile and chemotactic in vitro and are as able as the wild type to infect mice when they are the sole infecting strains. In contrast, when mice are coinfected with the
H. pylori
SS1
tlpA
or
tlpC
mutant and the wild type, we find more wild type than mutant after 2 weeks of colonization. Neither strain has an in vitro growth defect. These results suggest that the
tlpA
- and
tlpC
-encoded proteins assist colonization of the stomach environment.
Expression and Characterization of Flagella in Nonmotile Enteroinvasive
Escherichia coli
Isolated from Diarrhea Cases
Authors: Andrade Agda , Girón Jorge A. , Amhaz Juliana M. K. , Trabulsi Luiz R. , Martinez Marina B. 
Published: September 2002

ABSTRACT

We report that enteroinvasive
Escherichia coli
(EIEC) serotypes considered to be nonmotile produce an unusually large (77 kDa) flagellin that is assembled into functional flagellum filaments that allow the bacteria to swim in modified motility agar. The EIEC flagellin showed N-terminal identity to most common enterobacterial flagellins, especially those of the
E. coli
H7 serotype. These data are important in terms of the epidemiology, evolution, and biology of EIEC.
Identification and Characterization of the
N
-Acetylglucosamine Glycosyltransferase Gene of
Haemophilus ducreyi
Authors: Sun Shuhua , Scheffler N. Karoline , Gibson Bradford W. , Wang Jing , Munson Robert S. 
Published: September 2002

ABSTRACT

Haemophilus ducreyi
is the causative agent of chancroid, a sexually transmitted ulcerative disease. In the present study, the
Neisseria gonorrhoeae lgtA
lipooligosaccharide glycosyltransferase gene was used to identify a homologue in the genome of
H. ducreyi
. The putative
H. ducreyi
glycosyltransferase gene (designated
lgtA
) was cloned and insertionally inactivated, and an isogenic mutant was constructed. Structural studies demonstrated that the lipooligosaccharide isolated from the mutant strain lacked
N
-acetylglucosamine and distal sugars found in the lipooligosaccharide produced by the parental strain. The isogenic mutant was transformed with a recombinant plasmid containing the putative glycosyltransferase gene. This strain produced the lipooligosaccharide glycoforms produced by the parental strain, confirming that the
lgtA
gene encodes the
N
-acetylglucosamine glycosyltransferase.
Differential Survival of Lyme Borreliosis Spirochetes in Ticks That Feed on Birds
Authors: Kurtenbach Klaus , Schäfer Stefanie M. , Sewell Henna-Sisko , Peacey Mick , Hoodless Andrew , Nuttall Patricia A. , Randolph Sarah E. 
Published: September 2002

ABSTRACT

The abilities of the most common European genospecies of
Borrelia burgdorferi
sensu lato to survive blood meals taken by ticks feeding on birds were analyzed. A pattern of differential survival of the spirochetes in feeding ticks was observed. The result is consistent with the concept of selective transmission of Lyme borreliosis spirochetes.
Production and Characterization of Protective Human Antibodies against Shiga Toxin 1
Authors: Mukherjee Jean , Chios Kerry , Fishwild Dianne , Hudson Deborah , O'Donnell Susan , Rich Stephen M. , Donohue-Rolfe Arthur , Tzipori Saul 
Published: September 2002

ABSTRACTHemolytic-uremic syndrome (HUS) is a serious complication which is predominantly associated in children with infection by Shiga toxin-producingEscherichia coli(STEC). By using HuMAb-Mouse (Medarex) animals, human monoclonal antibodies (Hu-MAbs) were developed against Shiga toxin 1 (Stx1) for passive immunotherapy of HUS. Ten stable hybridomas comprised of fully human heavy- and light-chain immunoglobulin elements and secreting Stx1-specific Hu-MAbs (seven immunoglobulin M(κ) [IgM(κ)] elements [one specific for the A subunit and six specific for the B subunit] and three IgG1(κ) elements specific for subunit B) were isolated. Two IgM(κ) Hu-MAbs (2D9 and 15G9) and three IgG1(κ) Hu-MAbs (5A4, 10F4, and 15G2), all specific for subunit B, demonstrated marked neutralization of Stx1 in vitro and significant prolongation of survival in a murine model of Stx1 toxicosis.
Connexin37 Is the Major Connexin Expressed in the Media of Caudal Artery
Authors: Rummery Nicole M. , Hickey Haruyo , McGurk Gordon , Hill Caryl E. 
Published: September 2002

Objective—To determine the connexins (Cxs) involved in intercellular coupling within vascular muscle, the present study has quantified mRNA and protein expression for Cx37, Cx40, Cx43, and Cx45 in the caudal artery (CA) and thoracic aorta (ThA) of the rat.Methods and Results—Real-time polymerase chain reaction and immunohistochemistry identified Cx37 as the most abundantly expressed Cx in the CA, with fine punctate staining observed in the media. Conversely, mRNA for Cx43 was 40-fold greater in the ThA than in the CA, with punctate staining in the endothelium and media of the ThA but confined to the endothelium in the CA. Western blotting confirmed the differences in the relative amounts of Cx43 between the 2 vessels. For both arteries, Cx45 was expressed to a lesser degree in the media but not in the endothelium, whereas Cx40 was found only in the endothelium. Cx37, Cx40, and Cx43 were expressed in the endothelium of both vessels, although the density of Cx40 plaques was significantly greater in the CA.Conclusions—The demonstration of Cx37 as the dominant Cx in the media of the CA highlights the potential heterogeneity in Cx involvement in vascular smooth muscle.
Inhibition of Renin-Angiotensin System Ameliorates Endothelial Dysfunction Associated With Aging in Rats
Authors: Mukai Yasushi , Shimokawa Hiroaki , Higashi Midoriko , Morikawa Keiko , Matoba Tetsuya , Hiroki Junko , Kunihiro Ikuko , Talukder Hassan M.A. , Takeshita Akira 
Published: September 2002

Objective—Endothelial vasodilator functions are progressively impaired with aging, which may account in part for the increased incidence of cardiovascular events in elderly people. We examined what treatment could ameliorate the endothelial dysfunction associated with aging in rats.Methods and Results—Aged (12-month-old) Wistar-Kyoto rats were treated with vehicle, temocapril, CS-866 (an angiotensin II type 1 receptor antagonist), cerivastatin, or hydralazine for 2 weeks. Endothelium-dependent relaxations (EDRs) of aortas from aged rats were markedly impaired compared with EDRs of aortas from young (3-month-old) rats. Indomethacin, NS-398 (a cyclooxygenase [COX]-2 inhibitor), and SQ-29548 (a thromboxane A2/prostaglandin H2receptor antagonist) acutely restored EDRs in aged rats, suggesting an involvement of COX-2–derived vasoconstricting eicosanoids. Tiron, a superoxide scavenger, also partially improved EDRs, suggesting an involvement of superoxide. EDRs were significantly ameliorated in aged rats after long-term treatment with temocapril or CS-866 but not after treatment with cerivastatin or hydralazine. Indomethacin induced no further improvement of EDRs after treatment with temocapril or CS-866. COX-2 protein expression and superoxide production were increased in the aortas of aged rats and were also attenuated by treatment with temocapril or CS-866.Conclusions—These results demonstrate that long-term inhibition of the renin-angiotensin system ameliorates endothelial dysfunction associated with aging through the inhibition of the synthesis of COX-2–derived vasoconstricting factors and superoxide anions.
Quantitative Trait Loci and Candidate Genes Regulating HDL Cholesterol
Authors: Wang Xiaosong , Paigen Beverly 
Published: September 2002

Objective—Summarizing the many discovered mouse and human quantitative trait loci (QTL) for high density lipoprotein (HDL) cholesterol (HDL-C) levels is important for guiding future research on the genetic regulation of HDL concentrations and for finding gene targets for upregulating HDL levels in mice and humans.Methods and Results—We summarized the 27 QTL and candidate genes associated with HDL-C concentrations in mice and plotted them on a mouse chromosome map. We also summarized the 22 human QTL for HDL-C levels and compared them with those of the mouse by comparative genomics. At least part of the mouse homologies for 18 of the 22 human HDL-C QTL were within the murine HDL-C QTL.Conclusions—Murine QTL for HDL-C levels may predict their homologous location in humans, and their underlying genes may be appropriate genes to test in humans.
Emergence and evolution of Himalaya: reconstructing history in the light of recent studies
Authors: Valdiya K. S. 
Published: September 2002

India collided with mainland Asia at 65 Ma. The pressure rose to 9-11 kbar in the collision zone. As the Indian lithosphere bent down and its upper crust buckled up as an upwarp in the period 35-45 Ma, the southern margin of Asia became the water-divide of the Himalayan rivers. A variety of Eurasian fauna migrated to the Indian landmass. The southern margin of the Himalayan province synchronously sagged to give rise to the foreland basin that was linked with the Indian sea. In this Paleocene foreland basin 48-49 Ma ago, the whales from one of the species of the immigrant terrestrial mammals evolved. The sea retreated from the Himalayan province by the early Miocene, even as the crust broke up along faults 20-22 million years ago. The basement rocks, which had attained high-grade metamorphism at 600-800°C and 6-10 kbar, were thrust up to give rise to what later became the Himādri or Great Himalaya. Differential melting of the high-grade metamorphic rocks of the Himadri extensively produced 21 ± 1 Maold granites.Rivers carried detritus generated by the denudation of the fast emerging Himalaya and deposited it in the foreland basin which turned fluvial around 23 Ma. Another fluvial foreland basin, the Siwalik, was formed at ~18 Ma in front of the rapidly rising orogen and was filled by river-borne sediments at the rate of 20-30 cm year-1in the early stage and at 50-55 cm year-1later when the Himadri was uplifted and briskly exhumed in the Late Miocene (9-7.5 Ma). The Himadri then became high enough to cause disruption of wind circulation, culminating in the onset of monsoon. The climate change that followed caused migration of a variety of quadrupeds from Africa and Eurasia, bringing about considerable faunal turnovers in the Siwalik life.Spasmodic uplift of the outer ranges of the Lesser Himalaya and tectonic convulsion in the Siwalik domain at 1.6 Ma resulted in widespread landslides with debris flows and emplacement of the Upper Siwalik Boulder Conglomerate. Strong tectonic movements at 0.8 Ma caused the partitioning of the foreland basin into the rising Siwalik Hills and the subsiding IndoGangetic Plains, and also the initiation of glaciation in the uplifted domain of the Great Himalaya. After the end of the Pleistocene ice age around 0.2 Ma, there was oscillation of dry-cold and wet-warm climates. This climatic vicissitude is recorded in the sediments of the lakes that had formed because of reactivation of faults crossing rivers and streams. Activeness of faults, continuing uplift and current seismicity imply ongoing strain-buildup in the Himalayan domain.
Lack of Expression of Galectin-3 Is Associated With a Poor Outcome in Node-Negative Patients With Laryngeal Squamous-Cell Carcinoma
Authors: Piantelli Mauro , Iacobelli Stefano , Almadori Giovanni , Iezzi Manuela , Tinari Nicola , Natoli Clara , Cadoni Gabriella , Lauriola Libero , Ranelletti Franco O. 
Published: September 2002

PURPOSE: Galectin-3 is a pleiotropic carbohydrate-binding protein participating in a variety of normal and pathologic processes, including cancer progression. This study was aimed at evaluating the prognostic value of galectin-3 expression in node-negative laryngeal squamous-cell carcinoma (SCC). PATIENTS AND METHODS: Galectin-3 expression was analyzed by immunohistochemistry using M3/38 monoclonal antibody, in a single-institution series of 73 node-negative laryngeal SCC patients (median follow-up, 52 months; range, 2 to 90 months). RESULTS: Forty-two (57.5%) of 73 patients expressed galectin-3. Galectin-3 expression was positively associated with tumor keratinization and histologic grade. A significant correlation was found between galectin-3 tumor positivity and longer relapse-free and overall survival. In univariate analysis, high-grade (grade 3 or 4) tumors, nonkeratinizing tumors, and galectin-3–negative tumors showed a significantly increased risk of relapse and death. In multivariate analysis, only galectin-3 expression retained an independent prognostic significance for both relapse-free and overall survival. CONCLUSION: We conclude that the absence of galectin-3 expression is an independent negative prognostic marker in laryngeal SCC patients. Thus, histochemical detection of galectin-3 in these tumors could be useful for the selection of node-negative patients with potentially unfavorable outcomes, to establish adjuvant therapy protocols.