bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real Data, Real Learning and the London Olympics
Authors: Davies Neville 
Published: June 2006

AbstractThe Olympic and Paralympic Games are coming to London in 2012, and there will be huge interest, especially among the young. Could the Games be used to involve students of all ages in a large scale project that involves and interests them to break down their fear of statistics and to motivate learning? Neville Davies of the Royal Statistical Society Centre for Statistical Education appeals for help in a major teaching and learning initiative based on the London Olympics. Significance is proud to announce the launch of a scheme that could bring thousands of students, nationally and internationally, to appreciate and value the usefulness of statistics.
Molecular Cloning of a
Trypanosoma cruzi
Cell Surface Casein Kinase II Substrate, Tc-1, Involved in Cellular Infection
Authors: Augustine Swinburne A. J. , Kleshchenko Yuliya Y. , Nde Pius N. , Pratap Siddharth , Ager Edward A. , Burns James M. , Lima Maria F. , Villalta Fernando 
Published: June 2006

ABSTRACT

In this work, we report the cloning and characterization of the first cell surface casein kinase II (CKII) substrate (Tc-1) of
Trypanosoma cruzi
, the causative agent of Chagas' disease. Analysis of the gene sequence revealed a 1,653-bp open reading frame coding for 550 amino acid residues. Northern blot analysis showed a 4.5-kb transcript that is expressed in invasive trypomastigotes but not in noninvasive epimastigote forms of
T. cruzi
. Southern blot analysis indicates that Tc-1 is a single-copy gene. At the amino acid level, Tc-1 displayed 95% and 99% identity to two hypothetical proteins recently reported by the
T. cruzi
genome project. Analysis of the translated amino acid sequence indicates that the Tc-1 gene has a putative transmembrane domain with multiple cytoplasmic and extracellular CKII phosphosites. Exogenous human CKII was able to phosphorylate serine residues on both recombinant Tc-1 and Tc-1 of intact trypomastigotes. This phosphorylation was inhibited by the CKII inhibitors heparin and 4,5,6,7,-tetrabromo-2-azabenzimidazole. Immunoblots of solubilized trypomastigotes, epimastigotes, and amastigotes probed with anti-recombinant Tc-1 immunoglobulin G revealed a 62-kDa protein that is expressed only in infective trypomastigotes. Immunoprecipitation of labeled surface proteins of trypomastigotes indicated that the 62-kDa protein is a surface protein, and we found that the protein is uniformly distributed on the surface of trypomastigotes by direct immunofluorescence. Antibodies to Tc-1 effectively blocked trypomastigote invasion of host cells and consequently reduced parasite load. Preincubation of either trypomastigotes or myoblasts with CKII inhibitors blocked
T. cruzi
infection. Thus, for the first time, we describe a cell surface CKII substrate of a protozoan parasite that is phosphorylated by human CKII and that is involved in cellular infection.
Genetically Determined Susceptibility to Tuberculosis in Mice Causally Involves Accelerated and Enhanced Recruitment of Granulocytes
Authors: Keller Christine , Hoffmann Reinhard , Lang Roland , Brandau Sven , Hermann Corinna , Ehlers Stefan 
Published: June 2006

ABSTRACTClassical twin studies and recent linkage analyses of African populations have revealed a potential involvement of host genetic factors in susceptibility or resistance toMycobacterium tuberculosisinfection. In order to identify the candidate genes involved and test their causal implication, we capitalized on the mouse model of tuberculosis, since inbred mouse strains also differ substantially in their susceptibility to infection. Two susceptible and two resistant mouse strains were aerogenically infected with 1,000 CFU ofM. tuberculosis, and the regulation of gene expression was examined by Affymetrix GeneChip U74A array with total lung RNA 2 and 4 weeks postinfection. Four weeks after infection, 96 genes, many of which are involved in inflammatory cell recruitment and activation, were regulated in common. One hundred seven genes were differentially regulated in susceptible mouse strains, whereas 43 genes were differentially expressed only in resistant mice. Data mining revealed a bias towards the expression of genes involved in granulocyte pathophysiology in susceptible mice, such as an upregulation of those for the neutrophil chemoattractant LIX (CXCL5), interleukin 17 receptor, phosphoinositide kinase 3 delta, or gamma interferon-inducible protein 10. FollowingM. tuberculosischallenge in both airways or peritoneum, granulocytes were recruited significantly faster and at higher numbers in susceptible than in resistant mice. When granulocytes were efficiently depleted by either of two regimens at the onset of infection, only susceptible mice survived aerosol challenge withM. tuberculosissignificantly longer than control mice. We conclude that initially enhanced recruitment of granulocytes contributes to susceptibility to tuberculosis.
Early Events in
Mycobacterium tuberculosis
Infection in Cynomolgus Macaques
Authors: Lin Philana Ling , Pawar Santosh , Myers Amy , Pegu Amarenda , Fuhrman Carl , Reinhart Todd A. , Capuano Saverio V. , Klein Edwin , Flynn JoAnne L. 
Published: June 2006

ABSTRACT

Little is known regarding the early events of infection of humans with
Mycobacterium tuberculosis
. The cynomolgus macaque is a useful model of tuberculosis, with strong similarities to human tuberculosis. In this study, eight cynomolgus macaques were infected bronchoscopically with low-dose
M. tuberculosis
; clinical, immunologic, microbiologic, and pathologic events were assessed 3 to 6 weeks postinfection. Gross pathological abnormalities were observed as early as 3 weeks, including Ghon complex formation by 5 weeks postinfection. Caseous granulomas were observed in the lung as early as 4 weeks postinfection. Only caseous granulomas were observed in the lungs at these early time points, reflecting a rigorous initial response. T-cell activation (CD29 and CD69) and chemokine receptor (CXCR3 and CCR5) expression appeared localized to different anatomic sites. Activation markers were increased on cells from airways and only at modest levels on cells in peripheral blood. The priming of mycobacterium-specific T cells, characterized by the production of gamma interferon occurred slowly, with responses seen only after 4 weeks of infection. These responses were observed from T lymphocytes in blood, airways, and hilar lymph node, with responses predominantly localized to the site of infection. From these studies, we conclude that immune responses to
M. tuberculosis
are relatively slow in the local and peripheral compartments and that necrosis occurs surprisingly quickly during granuloma formation.
Cloning, Characterization, and Serodiagnostic Evaluation ofLeishmania infantumTandem Repeat Proteins
Authors: Goto Yasuyuki , Coler Rhea N. , Guderian Jeffrey , Mohamath Raodoh , Reed Steven G. 
Published: June 2006

ABSTRACTVisceral leishmaniasis (VL) is a form of leishmaniasis, which is caused by infection with the protozoan parasiteLeishmania, and is often fatal unless it is treated. Rapid and accurate diagnosis of VL is important for effective treatment. Here we report the cloning of previously undescribed tandem repeat (TR) proteins ofLeishmania infantumand an evaluation of VL patient antibody responses to the corresponding proteins. By screening anL. infantumexpression library with sera from human VL patients or infected hamsters, we identified 43 genes encoding B-cell antigens. Surprisingly, 19 of the 43 genes (44%) were TR proteins, and that percentage was significantly higher than that for genes picked randomly from the database. We then expressed the TR regions of LinJ16.1750, LinJ22.1590, and LinJ33.2870 and the entire LinJ28.2310 protein. These recombinant proteins were all recognized by Sudanese VL patient sera in an enzyme-linked immunosorbent assay. Recombinant LinJ16.1750 (rLinJ16.1750) showed the best performance among these antigens in terms of both sensitivity and specificity. Serological evaluation revealed that 97% (34 of 35) of Sudanese VL patients had significantly elevated antibody levels to rLinJ16.1750. Furthermore, when eight of the patient sera which had low reactivities to rK39 were tested with the novel recombinant antigens, some of the sera showed stronger antibody responses to these antigens than to rK39. Our results suggest that TR regions from the novelL. infantumproteins identified in this study are immunodominant B-cell epitopes and may represent good candidates for serodiagnosis of VL.
Alanine Esters of Enterococcal Lipoteichoic Acid Play a Role in Biofilm Formation and Resistance to Antimicrobial Peptides
Authors: Fabretti Francesca , Theilacker Christian , Baldassarri Lucilla , Kaczynski Zbigniew , Kropec Andrea , Holst Otto , Huebner Johannes 
Published: June 2006

ABSTRACT

Enterococcus faecalis
is among the predominant causes of nosocomial infections. Surface molecules like
d
-alanine lipoteichoic acid (LTA) perform several functions in gram-positive bacteria, such as maintenance of cationic homeostasis and modulation of autolytic activities. The aim of the present study was to evaluate the effect of
d
-alanine esters of teichoic acids on biofilm production and adhesion, autolysis, antimicrobial peptide sensitivity, and opsonic killing. A deletion mutant of the
dltA
gene was created in a clinical
E. faecalis
isolate. The absence of
d
-alanine in the LTA of the
dltA
deletion mutant was confirmed by nuclear magnetic resonance spectroscopy. The wild-type strain and the deletion mutant did not show any significant differences in growth curve, morphology, or autolysis. However, the mutant produced significantly less biofilm when grown in the presence of 1% glucose (51.1% compared to that of the wild type); adhesion to eukaryotic cells was diminished. The mutant absorbed 71.1% of the opsonic antibodies, while absorption with the wild type resulted in a 93.2% reduction in killing. Sensitivity to several cationic antimicrobial peptides (polymyxin B, colistin, and nisin) was considerably increased in the mutant strain, confirming similar results from other studies of gram-positive bacteria. Our data suggest that the absence of
d
-alanine in LTA plays a role in environmental interactions, probably by modulating the net negative charge of the bacterial cell surface, and therefore it may be involved in the pathogenesis of this organism.
Comparison of Different Live Vaccine Strategies In Vivo for Delivery of Protein Antigen or Antigen-Encoding DNA and mRNA by Virulence-AttenuatedListeria monocytogenes
Authors: Loeffler Daniela I. M. , Schoen Christoph U. , Goebel Werner , Pilgrim Sabine 
Published: June 2006

ABSTRACTListeria monocytogenescan be used to deliver protein antigens or DNA and mRNA encoding such antigens directly into the cytosol of host cells because of its intracellular lifestyle. In this study, we compare the in vivo efficiencies of activation of antigen-specific CD8 and CD4 T cells when the antigen is secreted byL. monocytogenesor when antigen-encoding plasmid DNA or mRNA is released by self-destructing strains ofL. monocytogenes. Infection of mice with self-destructingL. monocytogenescarriers delivering mRNA that encodes a nonsecreted form of ovalbumin (OVA) resulted in a significant OVA-specific CD8 T-cell response. In contrast, infection withL. monocytogenesdelivering OVA-encoding DNA failed to generate specific T cells. Secretion of OVA by the carrier bacteria yielded the strongest immune response involving OVA-specific CD8 and CD4 T cells. In addition, we investigated the antigen delivery capacity of a self-destructing, virulence-attenuatedL. monocytogenes aroA/Bmutant. In contrast to the wild-type strain, this mutant exhibited only marginal liver toxicity when high doses (5 × 107CFU per animal administered intravenously) were used, and it was also able to deliver sufficient amounts of secreted OVA into mice. Therefore, the results presented here could lay the groundwork for a rational combination ofL. monocytogenesas an attenuated carrier for the delivery of protein and nucleic acid vaccines in novel vaccination strategies.
Use of anActinobacillus pleuropneumoniaeMultiple Mutant as a Vaccine That Allows Differentiation of Vaccinated and Infected Animals
Authors: Maas Alexander , Jacobsen Ilse D. , Meens Jochen , Gerlach Gerald-F. 
Published: June 2006

ABSTRACTVaccination againstActinobacillus pleuropneumoniaeis hampered by the lack of vaccines inducing reliable cross-serotype protection. In contrast, pigs surviving natural infection are at least partially protected from clinical symptoms upon reinfection with any serotype. Thus, we set out to construct an attenuatedA. pleuropneumoniaelive vaccine allowing the differentiation of vaccinated from infected animals (the DIVA concept) by successively deleting virulence-associated genes. Based on anA. pleuropneumoniaeserotype 2 prototype live negative marker vaccine (W. Tonpitak, N. Baltes, I. Hennig-Pauka, and G.-F. Gerlach, Infect. Immun. 70:7120-7125, 2002), genes encoding three enzymes involved in anaerobic respiration and the ferric uptake regulator Fur were deleted, resulting in a highly attenuated sixfold mutant; this mutant was still able to colonize the lower respiratory tract and induced a detectable immune response. Upon a single aerosol application, this mutant provided significant protection from clinical symptoms upon heterologous infection with an antigenically distinctA. pleuropneumoniaeserotype 9 challenge strain and allowed the serological discrimination between infected and vaccinated groups.
Serologic Proteome Analysis ofBorrelia burgdorferiMembrane-Associated Proteins
Authors: Nowalk Andrew J. , Gilmore Robert D. , Carroll James A. 
Published: June 2006

ABSTRACTLyme disease, a global health concern, is caused by infection withBorrelia burgdorferi,B. afzelii, orB. garinii. The spirochete responsible for the disease in the United States isB. burgdorferiand is spread by the bite of an infectedIxodestick. We utilized multiple two-dimensional gel techniques combined with proteomics to reveal the full humoral immune response of mice and Lyme patients to membrane-associated proteins isolated fromBorrelia burgdorferi. Our studies indicated that a subset of immunogenic membrane-associated proteins (some new and some previously identified) was recognized by mice experimentally infected withBorrelia burgdorferieither by low-dose needle inoculation or by tick infestation. Moreover, the majority of these immunogenic membrane-associated proteins were recognized by sera from patients diagnosed with early-disseminated Lyme disease. These included RevA, ErpA, ErpP, DbpA, BmpA, FtsZ, ErpB, LA7, OppA I, OppA II, OppA IV, FlhF, BBA64, BBA66, and BB0323. Some immunogens (i.e., BBI36/38) were more reactive with sera from mice than Lyme patients, while additional membrane proteins (i.e., FlaB, P66, LA7, and Hsp90) were recognized more strongly with sera from patients diagnosed with early-localized, early-disseminated, or late (chronic)-stage Lyme disease. We were able to examine the humoral response in Lyme patients in a temporal fashion and to identify the majority of immunoreactive proteins as the disease progresses from early to late stages. This serologic proteome analysis enabled the identification of novel membrane-associated proteins that may serve as new diagnostic markers and, more importantly, as second-generation vaccine candidates for protection against Lyme disease.
Low-Phosphate-Dependent Invasion Resembles a General Way for
Neisseria gonorrhoeae
To Enter Host Cells
Authors: Kühlewein Christiane , Rechner Cindy , Meyer Thomas F. , Rudel Thomas 
Published: June 2006

ABSTRACT

Obligate human-pathogenic
Neisseria gonorrhoeae
expresses numerous variant surface proteins mediating adherence to and invasion of target cells. The invariant major outer membrane porin PorB of serotype A (P.IA) gonococci triggers invasion into Chang cells only if the medium is devoid of phosphate. Since gonococci expressing PorB
IA
are frequently isolated from patients with severe disseminating infections, the interaction initiated by the porin may be of major relevance for the development of this serious disease. Here, we investigated the low-phosphate-dependent invasion and compared it to the well-known pathways of entry initiated by Opa proteins. P.IA-triggered invasion requires clathrin-coated pit formation and the action of actin and Rho GTPases. However, in contrast to Opa-initiated invasion via heparan sulfate proteoglycans, microtubules, acidic sphingomyelinase, phosphatidylinositol 3-kinase, and myosin light chain kinase are not involved in this entry pathway. Nor are Src kinases required, as they are in invasion, e.g., via the CEACAM3 receptor. Invasion by PorB
IA
occurs in a wide spectrum of cell types, such as primary human epithelial and endothelial cells and in cancer cells of human and animal origin. Low-phosphate-dependent invasion is thus a pathway of gonococcal entry distinct from Opa-mediated invasion.
Hybridoma Passage In Vitro May Result in Reduced Ability of Antimannan Antibody To Protect against Disseminated Candidiasis
Authors: Xin Hong , Cutler Jim E. 
Published: June 2006

ABSTRACTWe previously reported the enhanced resistance of monoclonal antibodies B6.1 (an immunoglobulin M [IgM]) and C3.1 (an IgG3) against experimental candidiasis. Both MAbs recognize the same fungal epitope. We have since found that a highly passaged B6.1 hybridoma (hp-B6.1) resulted in antibody that has little protective potential. The potential clinical applicability of the antibody and our interest in understanding antibody protection against candidiasis led us to investigate an explanation for this phenomenon. Antibody genetic structure of hp-B6.1, the original hybridoma clone (ori-B6.1) stored frozen since 1995, a subclone of hp-B6.1 that produces protective antibody, the IgG3-producing hybridoma, and a nonprotective IgG1-producing hybridoma were compared. Variable region gene sequences of heavy (VH) and light chains showed genetic instability of VHchains with only the hp-B6.1; the VHsequences from ori-B6.1 and the subclone were, however, identical. Activation-induced cytidine deaminase levels were greatest in the B6.1 hybridomas, which may explain the instability. The constant region CH3 domain remained unchanged, implying normalN-glycation and complement-fixing potential, and antibody binding affinities appeared unchanged. Complement fixation assays surprisingly showed that ori-B6.1 antibody fixes C3 more rapidly than does hp-B6.1 antibody. The VHregion primary structure may affect complement activation, which could explain our result. Indeed, antibody from the hp-B6.1 subclone fixed complement like antibody from ori-B6.1. These results show that the greatest protection occurs when antimannan antibodies possess the dual abilities of recognizing the appropriate carbohydrate epitope and rapidly fixing complement; loss of the latter property results in the loss of protective potential by the antibody.
TheYersinia enterocoliticaInvasin Protein Promotes Major Histocompatibility Complex Class I- and Class II-Restricted T-Cell Responses
Authors: Bühler O. T. , Wiedig C. A. , Schmid Y. , Grassl G. A. , Bohn E. , Autenrieth I. B. 
Published: June 2006

ABSTRACTYersinia enterocoliticainvasin (Inv) protein confers internalization into and expression of proinflammatory cytokines by host cells. Both events require binding of Inv to β1 integrins, which initiates signaling cascades including activation of focal adhesion complexes, Rac1, mitogen-activated protein kinase, and NF-κB. Here we tested whether Inv might be suitable as a delivery molecule and adjuvant if used as a component of a vaccine. For this purpose, hybrid proteins composed of Inv and ovalbumin (OVA) were prepared, applied as a coating to microparticles, and used for vaccination. Fusion of OVA to Inv did not significantly disturb the ability of Inv to promote host cell binding, internalization, and interleukin-8 (IL-8) secretion when applied as a coating to microparticles. The microparticles were used for vaccination of mice adoptively transferred with OVA-specific T cells from OT-1 or DO11.10 mice. Administration of OVA-Inv-coated microparticles induced OVA-specific T-cell responses. OVA-specific CD4 T cells produced both gamma interferon (IFN-γ) and IL-4 as determined by enzyme-linked immunosorbent assay. Likewise, pronounced OVA-specific CD8 T-cell responses associated with IFN-γ production were observed. Together, these results suggest that Inv might be an attractive tool in vaccination as it confers both host cell uptake and adjuvant activity by engagement of β1 integrins of host cells, which leads to CD4 as well as CD8 T-cell responses.
Responses toLeishmania donovaniin Mice Deficient in Interleukin-12 (IL-12), IL-12/IL-23, or IL-18
Authors: Murray Henry W. , Tsai Christine W. , Liu Jianguo , Ma Xiaojing 
Published: June 2006

ABSTRACTInterleukin-12 (IL-12) orchestrates acquired resistance in intracellularLeishmania donovaniinfection in the liver, inducing gamma interferon and, in turn, macrophage activation and parasite killing. Nevertheless, testing in IL-18−/−mice compared to wild-type mice and in IL-12p40−/−compared to IL-12p35−/−mice also suggested both early-acting (IL-18) and late-acting (IL-23) antileishmanial effects independent of IL-12.
Stabilization of a Plasmid Coding for a Heterologous Antigen in
Salmonella enterica
Serotype Typhi Vaccine Strain CVD908-
htrA
by Using Site-Specific Recombination
Authors: Stephens Jonathan C. , Darsley Michael J. , Turner Arthur K. 
Published: June 2006

ABSTRACT

A gene cassette incorporating the
crs-rsd
site-specific recombination system from the
Salmonella enterica
subsp.
enterica
serovar Dublin virulence plasmid improved the inheritance in
S. enterica
serotype Typhi strain CVD908-
htrA
of a multicopy plasmid expression vector. Use of this recombination cassette may improve expression of heterologous antigens from multicopy plasmid expression vectors in attenuated bacterial vaccine strains.
Proinflammatory and Immunomodulatory Cytokine mRNA Time Course Profiles in Hamsters Infected with a Virulent Variant of
Leptospirainterrogans
Authors: Vernel-Pauillac Frédérique , Merien Fabrice 
Published: June 2006

ABSTRACT

In order to quantify in vivo the mRNAs of cytokines which play important
roles in leptospirosis, we have developed quantitative real-time PCR
assays for interleukin-2 (IL-2), IL-4, IL-10, IL-12p40, tumor necrosis
factor alpha (TNF-α), gamma interferon (IFN-γ),
transforming growth factor β, and two housekeeping genes
(encoding β-actin and hypoxanthine phosphoribosyltransferase).
We used a lethal hamster model reflecting severe leptospirosis in
humans. The LightCycler system was used to quantify the gene expression
levels with the SYBR green I detection format using external standard
curves for each target. We compared the expression levels of cytokine
mRNA in the peripheral blood mononuclear cells of both control
(uninfected) hamsters and
Leptospira interrogans
-inoculated
hamsters from 1 to 24 h and then 1 to 4 days postinfection.
In this kinetic study, there was pronounced expression of Th1 cytokine
mRNA (TNF-α, IFN-γ, and IL-12), with transcripts being
detected as early as 1 h postinfection. Expression of
anti-inflammatory cytokines, such as IL-4 and IL-10, was prominent in
delayed samples from 1 to 4 days postinfection in response to infection
with
Leptospira interrogans
. Our data are the first to
establish that pathogenic leptospires can stimulate in vivo the
production of type 1 cytokines involved in cellular immunity by using
this informative animal model. Measuring and assessing cytokine
profiles may provide a useful method for accurate study of the
mechanisms of anti-
Leptospira
immunity, indications of
prognosis factors, and prospective evaluation of leptospirosis vaccine
efficacy in
humans.