bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification ofActinobacillus pleuropneumoniaeGenes Important for Survival during Infection in Its Natural Host
Authors: Sheehan Brian J. , Bossé Janine T. , Beddek Amanda J. , Rycroft Andrew N. , Kroll J. Simon , Langford Paul R. 
Published: June 2003

ABSTRACTActinobacillus pleuropneumoniaeis a strict respiratory tract pathogen of swine and is the causative agent of porcine pleuropneumonia. We have used signature-tagged mutagenesis (STM) to identify genes required for survival of the organism within the pig. A total of 2,064 signature-tagged Tn10transposon mutants were assembled into pools of 48 each, and used to inoculate pigs by the endotracheal route. Out of 105 mutants that were consistently attenuated in vivo, only 11 mutants showed a >2-fold reduction in growth in vitro compared to the wild type, whereas 8 of 14 mutants tested showed significant levels of attenuation in pig as evidenced from competitive index experiments. Inverse PCR was used to generate DNA sequence of the chromosomal domains flanking each transposon insertion. Only one sibling pair of mutants was identified, but three apparent transposon insertion hot spots were found—an anticipated consequence of the use of a Tn10-based system. Transposon insertions were found within 55 different loci, and similarity (BLAST) searching identified possible analogues or homologues for all but four of these. Matches included proteins putatively involved in metabolism and transport of various nutrients or unknown substances, in stress responses, in gene regulation, and in the production of cell surface components. Ten of the sequences have homology with genes involved in lipopolysaccharide and capsule production. The results highlight the importance of genes involved in energy metabolism, nutrient uptake and stress responses for the survival ofA. pleuropneumoniaein its natural host: the pig.
Different Strains ofToxoplasma gondiiInduce Different Cytokine Responses in CBA/Ca Mice
Authors: Araujo Fausto G. , Slifer Teri 
Published: June 2003

ABSTRACTTo investigate the role that cytokines may have in the development of toxoplasmic encephalitis (TE), the levels of gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin-12 (IL-12 ]p40[), IL-10, IL-6, IL-4, and IL-2 in serum were examined in CBA/Ca mice infected with a type II strain (ME49 or FORT) ofToxoplasma gondii. These strains caused severe (ME49) or mild (FORT) TE in CBA/Ca mice. From weeks 1 to 8 of infection, the levels of IL-6, IL-10, IL-12, IFN-γ, and TNF-α in serum were significantly higher in the ME49-infected mice than in the FORT-infected mice, suggesting a role for these cytokines in the severity of TE in CBA/Ca mice. Since the ME49 and FORT strains are of the same type, our results suggest a role for the parasite in the development of severe TE through the increased production of proinflammatory cytokines and indicate that not all type II strains cause TE.
Swing-leg retraction: a simple control model for stable running
Authors: Seyfarth André , Geyer Hartmut , Herr Hugh 
Published: June 2003

SUMMARY
In running, the spring-like axial behavior of stance limbs is a well-known and remarkably general feature. Here we consider how the rotational behavior of limbs affects running stability. It is commonly observed that running animals retract their limbs just prior to ground contact, moving each foot rearward towards the ground. In this study, we employ a conservative spring-mass model to test the effects of swing-leg retraction on running stability. A feed-forward control scheme is applied where the swing-leg is retracted at constant angular velocity throughout the second half of the swing phase. The control scheme allows the spring-mass system to automatically adapt the angle of attack in response to disturbances in forward speed and stance-limb stiffness. Using a return map to investigate system stability, we propose an optimal swing-leg retraction model for the stabilization of flight phase apex height. The results of this study indicate that swing-leg retraction significantly improves the stability of spring-mass running,suggesting that swing-phase limb dynamics may play an important role in the stabilization of running animals.
A biomechanical analysis of intra- and interspecific scaling of jumping and morphology in CaribbeanAnolislizards
Authors: Toro Esteban , Herrel Anthony , Vanhooydonck Bieke , Irschick Duncan J. 
Published: June 2003

SUMMARYScaling models predict how functional variables change as animals grow or increase in size evolutionarily. However, few experimental studies have found support for the predictions of these models. Here, we use a force plate to investigate the scaling of functional variables associated with jumping within(for three species) and across adults of 12 species of Anolislizards. Both ontogenetically (with the exception of Anolis carolinensis) and across the 12 species examined, limb dimensions increased geometrically, making Anolis lizards an ideal study system to test the predictions of geometric scaling models. However, both the ontogenetic and interspecific scaling of functional variables deviated in several aspects from model predictions. Unexpectedly, the scaling of functional variables such as acceleration differed for different species. Whereas acceleration capacity increases with hindlimb length for A. carolinensis, no relationship was detected for the other two species. Interspecifically, the inclusion of two large species in our analysis appears to drive the absence of a correlation between acceleration capacity and hindlimb length across species. These data suggest that selection for enhanced jumping performance is relaxed in larger anoles and support the notion that no scaling model seems to be able to comprehensively predict changes in function with size across species; rather, natural selection seems to drive changes in the scaling relationships of some key variables such as force output or acceleration capacity.
Glenoid version and rotator cuff tears
Authors: Tétreault Patrice , Krueger Andreas , Zurakowski David , Gerber Christian 
Published: June 2003

AbstractThe purpose of this study was to determine the relationship between rotator cuff (RC) tear and the orientation of the glenoid. Ninety‐six shoulders (94 patients) that underwent open RC repair were grouped according to the type of tear. We measured on MRI the acromio–glenoid angle (AG) and the supraspinatus fossa glenoid angle on the anterior–posterior (SGAP) and axial (SGAX) views. RC patients had a smaller AG angle (76 ± 7° vs. 86 ± 10°) and a larger SGAP angle (112 ± 6° vs. 102 ± 7°) compared to controls (p < 0.001). We also found a highly significant difference (p < 0.001) in glenoid version measured by SGAX between anterior cuff tears (–5 ± 4°) and posterior cuff tears (3 ± 3°). Furthermore, we identified an association between RC tear and the orientation of the glenoid relative to the axis of the supraspinatus fossa. Greater retroversion is predictive of an anterior cuff injury and greater anteversion is predictive of a posterior cuff injury. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Staphylococcus aureusSusceptibility to Innate Antimicrobial Peptides, β-Defensins and CAP18, Expressed by Human Keratinocytes
Authors: Midorikawa Kazushige , Ouhara Kazuhisa , Komatsuzawa Hitoshi , Kawai Toshihisa , Yamada Sakuo , Fujiwara Tamaki , Yamazaki Kenshi , Sayama Koji , Taubman Martin A. , Kurihara Hidemi , Hashimoto Koji , Sugai Motoyuki 
Published: June 2003

ABSTRACTThe antimicrobial peptides human β-defensin-1 (hBD1), hBD2, hBD3, and CAP18 expressed by keratinocytes have been implicated in mediation of the innate defense against bacterial infection. To gain insight intoStaphylococcus aureusinfection, the susceptibility ofS. aureus, including methicillin-resistantS. aureus(MRSA), to these antimicrobial peptides was examined. Based on quantitative PCR, expression of hBD2 mRNA by human keratinocytes was significantly induced by contact withS. aureus, and expression of hBD3 and CAP18 mRNA was slightly induced, while hBD1 mRNA was constitutively expressed irrespective of the presence ofS. aureus. Ten clinicalS. aureusisolates, including five MRSA isolates, induced various levels of expression of hBD2, hBD3, and CAP18 mRNA by human kertinocytes. The activities of hBD3 and CAP18 againstS. aureuswere found to be greater than those of hBD1 and hBD2. A total of 44S. aureusclinical isolates, including 22 MRSA strains, were tested for susceptibility to hBD3 and CAP18. Twelve (55%) and 13 (59%) of the MRSA strains exhibited more than 20% survival in the presence of hBD3 (1 μg/ml) and CAP18 (0.5 μg/ml), respectively. However, only three (13%) and two (9%) of the methicillin-sensitiveS. aureusisolates exhibited more than 20% survival with hBD3 and CAP18, respectively, suggesting that MRSA is more resistant to these peptides. A synergistic antimicrobial effect between suboptimal doses of methicillin and either hBD3 or CAP18 was observed with 10 MRSA strains. Furthermore, of several genes associated with methicillin resistance, inactivation of thefmtCgene in MRSA strain COL increased susceptibility to the antimicrobial effect mediated by hBD3 or CAP18.
Helicobacter pyloriInduces RANTES through Activation of NF-κB
Authors: Mori Naoki , Krensky Alan M. , Geleziunas Romas , Wada Akihiro , Hirayama Toshiya , Sasakawa Chihiro , Yamamoto Naoki 
Published: June 2003

ABSTRACTHelicobacter pylori-infected gastric mucosa displays a conspicuous infiltration of mononuclear cells and neutrophils. RANTES (short for “regulated upon activation, normal T cell expressed and secreted”) is a chemoattractant cytokine (chemokine) important in the infiltration of T lymphocytes and monocytes. RANTES may therefore contribute to the cellular infiltrate in theH. pylori-infected gastric mucosa. The aim of this study was to analyze the molecular mechanism responsible forH. pylori-mediated RANTES expression. We observed that gastric epithelial cells produced RANTES upon coculture withH. pylori. In addition,H. pyloriinduced RANTES mRNA expression and an increase in luciferase activity in cells which were transfected with a luciferase reporter construct derived from the RANTES promoter, in gastric epithelial cells, indicating that the induction of RANTES production occurred at the transcriptional level. Induction of RANTES was dependent on an intactcagpathogenicity island. Activation of the RANTES promoter byH. pylorioccurred through the action of NF-κB. Transfection of kinase-deficient mutants of IκB kinase (IKK) and NF-κB-inducing kinase (NIK) inhibitedH. pylori-mediated RANTES activation. In contrast, tumor necrosis factor alpha- or interleukin-1/Toll-like receptor signaling molecules—such as mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1, MyD88, and interleukin-1 receptor-associated kinase—did not play a role in RANTES activation byH. pylori. Collectively,H. pyloriinduced NF-κB activation through an intracellular signaling pathway that involved IKK and NIK, leading to RANTES gene transcription. RANTES induction byH. pylorimay play an important role in gastric inflammation.
Various Types ofDirofilaria immitisPolyproteins Selectively Induce a Th2-Type Immune Response
Authors: Tezuka Hiroyuki , Imai Shinjiro , Hidano Shinya , Tsukidate Setsuko , Fujita Koichiro 
Published: June 2003

ABSTRACTDirofilaria immitispolyproteins (DiAgs) are found as 15-kDa monomeric and 30-kDa dimeric forms in exceretory-secretory products of the adult worm. We evaluated the ability of various types of recombinant DiAg (rDiAg; V1 and V2 as monomers and V1V2, V2V1, V1V1, and V2V2 as dimers) to influence Th1/Th2 immune responses. V1-, V1Vx- and V2-, V2Vx-driven nonspecific immunoglobulin E (IgE) production peaked at 21 and 14 days after administration, respectively. Dimer-induced IgE response was an interesting biphasic pattern with the second peaks on days 35 (V2Vx) or 42 (V1Vx). Absolute amounts of nonspecific IgE production induced with monomers were larger than those observed with dimers at the first peak. The magnitude of cell expansion and interleukin-10 (IL-10) production in mesenteric lymph node (MLN) B-cell induced with rDiAgs was linked to the levels of the first IgE peak in vivo and IgE produced by rDiAg plus IL-4-stimulated B cells in vitro. All rDiAgs failed to augment IgG2c production. V2 and V2Vx elicited IL-4 production by MLN cells more rapidly than V1 and V1Vx. The inhibitory effect of rDiAg on gamma interferon (IFN-γ) production was stronger in monomers than in dimers. Neutralization of IL-10 restored IFN-γ production, whereas the expression of IL-4 and IgE was partly prevented by depletion of IL-10. These results indicate that monomer rather than dimer is an efficient form of DiAg and suggest that the difference of IgE-inducing capacity among these DiAgs is closely associated with the pattern of both B-cell activation and IL-4 production.
Antigenic Properties of HpaA and Omp18, Two Outer Membrane Proteins ofHelicobacter pylori
Authors: Voland Petra , Hafsi Nadia , Zeitner Marco , Laforsch Stephanie , Wagner Hermann , Prinz Christian 
Published: June 2003

ABSTRACTOuter membrane proteins (OMPs) are incorporated into the outer plasma membrane ofHelicobacter pyloriand are important for, e.g., ion transport, adherence, structural and osmotic stability, and bacterial virulence but may also be antigenic due to their surface exposure. Previous proteome-based approaches withH. pylorilysates determined a strong serological reaction towards twoH. pyloriOMPs, HpaA (TIGR HP0797) and Omp18 (TIGR HP1125). PCR was used to detect DNA encoding the two proteins, and a positive signal was found in allH. pyloristrains tested. Proteins were cloned and expressed in the human kidney cell line HK293 with the QiaExpressionist system with a C-terminal His tag. Only sera from infected persons showed a positive reaction with the recombinant proteins. Recombinant HpaA (rHpaA) and rOmp18 were incubated with human peripheral blood mononuclear cells and induced secretion of interleukin-12 (IL-12) and IL-10 from these cells. To determine the effect on antigen-presenting cells, human blood monocytic and dendritic cells (DCs) were isolated by magnetic cell separation. rOmp18 and rHpaA strongly stimulated major histocompatibility class II and CD83 expression 7- to 10-fold on isolated DCs. rHpaA and rOmp18 failed to stimulate IL-8 secretion from monocytes but increased secretion of IL-12 and IL-10 from DCs significantly. In summary, HpaA and Omp18 are recognized by human dendritic cells and induce their maturation as well as antigen presentation. HpaA and Omp18 ofH. pylorithereby appear to have a specific antigenic potential in humans.
Host-Adapted
Borrelia burgdorferi
in Mice Expresses OspA during Inflammation
Authors: Crowley Helena , Huber Brigitte T. 
Published: June 2003

ABSTRACT

Antibody responses to outer surface protein A (OspA) of
Borrelia burgdorferi
may occur during periods of arthritis late in the clinical course of untreated Lyme disease. These antibody responses are paradoxical, given the conclusive evidence demonstrating that
B. burgdorferi
transmitted to the mammalian host expresses little or no OspA. The parallel occurrence of OspA antibodies and arthritic episodes suggests that OspA expression is upregulated during infection with
B. burgdorferi
. We hypothesized that this was due to the inflammatory environment caused by the immune response to the spirochete. To test our hypothesis, we adapted an in vivo model that mimics the host-pathogen interaction. Dialysis chambers containing
B. burgdorferi
were implanted into the peritoneal cavities of mice in the presence or absence of zymosan, a yeast cell wall extract that induces inflammation. Spirochetes were harvested 2 days later, and OspA expression was assessed at the protein and transcription level by Western blotting and real-time reverse transcription-PCR, respectively. Flow cytometry was also utilized to evaluate OspA protein expression on individual spirochetes.
B. burgdorferi
maintained in an inflammatory in vivo environment show an increased OspA expression relative to
B. burgdorferi
kept under normal in vivo conditions. Furthermore, host-adapted
B. burgdorferi
with a low OspA phenotype upregulates OspA expression when transferred to an inflammatory in vivo environment. The results obtained by these techniques uniformly identify inflammation as a mediator of in vivo OspA expression in host-adapted
B. burgdorferi
, providing insights into the behavior of live spirochetes in the mammalian host.
Toll-Like Receptor 4-Defective C3H/HeJ Mice Are Not More Susceptible than Other C3H Substrains to Infection withMycobacterium tuberculosis
Authors: Kamath Arati B. , Alt Jennifer , Debbabi Hajer , Behar Samuel M. 
Published: June 2003

ABSTRACTMycobacterium tuberculosisproduces a variety of molecules capable of activating Toll-like receptors, a family of pattern recognition receptors expressed by macrophages and a variety of other cells. To determine whether Toll-like receptor 4 (TLR4) was critical in resistance toM.tuberculosisinfection, we compared the morbidity and mortality of TLR4-defective C3H/HeJ mice to those of TLR4-sufficient C3H mouse substrains. TLR4-defective C3H/HeJ mice and TLR4-sufficient C3H/HeSnJ, C3HeB/FeJ, and C3H/HeOuJ mice were infected by the aerosol route withM.tuberculosis. TLR4-defective C3H/HeJ mice had levels of cytokines in their bronchoalveolar lavage fluids and in vitro mycobacterial antigen-specific recall responses similar to those of other C3H mouse substrains. In addition, bacterial replication and long-term survival of mice following infection appeared to be independent of TLR4. Interestingly, C3HeB/FeJ mice were significantly more susceptible toM.tuberculosisinfection, indicating that genetic heterogeneity among inbred C3H mouse substrains modifies resistance to infection. Therefore, cautious interpretation is required when the C3H/HeJ strain is used as a model of a TLR4-defective mouse strain, as there are significant allelic differences between C3H/HeJ and other C3H mouse substrains in response toM.tuberculosisinfection. With this caveat, our data indicate that TLR4 may not be required for optimal immunity of mice toM.tuberculosis.
Daily variations of endolymph composition: relationship with the otolith calcification process in trout
Authors: Borelli G. , Guibbolini M. E. , Mayer-Gostan N. , Priouzeau F. , De Pontual H. , Allemand D. , Puverel S. , Tambutte E. , Payan P. 
Published: June 2003

SUMMARYIonic and organic parameters of the otolith calcification process in the trout Oncorhynchus mykiss were analysed in plasma and endolymph over the day:night cycle. Plasma pH remained constant and total CO2concentration was significantly lower (by 21%) during the day than at night. Calcifying parameters (total CO2, total calcium concentration) were measured in the proximal and distal endolymphs and were unchanged in the latter during the day:night cycle, but fluctuated in the former. Non-collagenous protein and collagen concentrations in endolymph were higher(1.5- and 10-fold, respectively) during the day than at night. As there was no change in total calcium concentration, we propose that Ca2+increases during the dark period and was maximal by the end of the night when the total CO2 concentration has also increased (by 14%). Measurements of endolymph pH in situ revealed significant differences between samples from proximal and distal endolymph (7.38 and 7.87,respectively), but no variation between values obtained during the day and at night. Thus, the saturation state of aragonite (Sa) in the proximal endolymph should fluctuate around unity during the day:night cycle, and CaCO3precipitation should occur when supersaturation is reached. The electrophoretic pattern of proximal endolymph showed variations in both major and minor components. Immunoblotting of endolymph, using a rabbit antiserum raised against the otolith soluble organic matrix revealed an increase in the expression of two proteins (65 kDa and 75 kDa) during the day period. We propose that organic matrix and calcium carbonate deposition on the otolith vary antiphasically: organic matrix deposition begins by the end of the day period, when the concentration of organic precursors is maximal in the endolymph, whereas CaCO3 precipitation starts once the solubility of CaCO3 is exceeded.
Effect of Heat Shock and Mutations in ClpL and ClpP on Virulence Gene Expression inStreptococcus pneumoniae
Authors: Kwon Hyog-Young , Kim Seung-Whan , Choi Moo-Hyun , Ogunniyi A. David , Paton James C. , Park Sin-Hee , Pyo Suhk-Neung , Rhee Dong-Kwon 
Published: June 2003

ABSTRACTSpread ofStreptococcus pneumoniaefrom the nasopharynx to other host tissues would require the organism to adapt to a variety of environmental conditions. Since heat shock proteins are induced by environmental stresses, we investigated the effect of heat shock on ClpL and ClpP synthesis and the effect ofclpLandclpPmutations on the expression of key pneumococcal virulence genes. Pulse labeling with [35S]methionine and chase experiments as well as immunoblot analysis demonstrated that ClpL, DnaK, and GroEL were stable. Purified recombinant ClpL refolded urea-denatured rhodanese in a dose-dependent manner, demonstrating ClpL's chaperone activity. Although growth of theclpLmutant was not affected at 30 or 37°C, growth of theclpPmutant was severely affected at these temperatures. However, bothclpLandclpPmutants were sensitive to 43°C. Although it was further induced by heat shock, the level of expression of ClpL in theclpPmutant was high at 30°C, suggesting that ClpP represses expression of ClpL. Furthermore, theclpPmutation significantly attenuated the virulence ofS. pneumoniaein a murine intraperitoneal infection model, whereas theclpLmutation did not. Interestingly, immunoblot and real-time reverse transcription-PCR analysis demonstrated that pneumolysin and pneumococcal surface antigen A were induced by heat shock in wild-typeS. pneumoniae.Other virulence genes were also affected by heat shock andclpLandclpPmutations. Virulence gene expression seems to be modulated not only by heat shock but also by the ClpL and ClpP proteases.