bluuebunny/crossref_metadata_2025 huggingface dataset:
Differences in the
Enterococcus faecalis lsa
Locus That Influence Susceptibility to Quinupristin-Dalfopristin and Clindamycin
Authors: Singh Kavindra V. , Murray Barbara E.
Published: December 2004

We have previously shown that the
Enterococcus faecalis lsa
gene, encoding the putative ABC protein Lsa, influences resistance to quinupristin-dalfopristin (Q-D) and clindamycin (CLI). We have now found that, while cloned
lsa
from
E. faecalis
strain V583 (
lsa
V
) fully restored resistance to Q-D, CLI, and dalfopristin (DAL) lost by the OG1
lsa
disruption mutant TX5332 and also caused increased MICs for
Lactococcus lactis
LM2301, cloned
lsa
from OG1 (
lsa
OG
) did not cause any increase in MICs for either species. Sequencing of ca. 2 kb of these two
lsa
alleles found differences between
lsa
OG
and
lsa
V
in the upstream region as well as in the 5′ and 3′ halves of the
lsa
gene. To investigate the reason for the phenotypic differences expressed by the two cloned loci, 5′ half plus 3′ half hybrid constructs were created. When introduced into both TX5332 and
L. lactis
, cloned
lsa
V5
′
OG3
′
conferred increases in MICs of Q-D, CLI, and DAL similar to those of cloned
lsa
V
while cloned
lsa
OG5
′
V3
′
showed a moderate increase in MICs relative to those of
lsa
OG
, indicating that both halves of the locus can influence resistance expression. After site-directed mutagenesis of the cloned
lsa
alleles at positions −131 and −133 (relative to the putative Lsa start codon ATG), which converted two A's of
lsa
V
to the G and T of
lsa
OG
and vice versa, MIC testing showed that mutagenized
lsa
OG
(
lsa
OG-M
) was strongly influenced by these changes in terms of conferring increased MICs of Q-D, CLI, and DAL relative to
lsa
OG
while the phenotype of mutagenized
lsa
V
(
lsa
V-M
) was less influenced, with moderately decreased MICs, primarily to CLI, relative to
lsa
V
. In conclusion, this study found that changes in different regions of the
E. faecalis lsa
locus influence the ability of cloned
lsa
to confer resistance to Q-D, CLI, and DAL.
Hemolysis of Erythrocytes by Granulysin-Derived Peptides but Not by Granulysin
Authors: Li Qing , Dong Chen , Deng Anmei , Katsumata Masao , Nakadai Ari , Kawada Tomoyuki , Okada Satoshi , Clayberger Carol , Krensky Alan M.
Published: December 2004

Granulysin, a 9-kDa protein localized in human cytolytic T lymphoctyes and natural killer cell granules, is cytolytic against tumors and microbes but not against red blood cells. Synthetic peptides corresponding to the central region of granulysin recapitulate the lytic activity of the intact molecule, and some peptides cause hemolysis of red blood cells. Peptides in which cysteine residues were replaced by serine maintain their activity against microbes but lose activity against human cells, suggesting their potential as antibiotics. Studies were undertaken to determine the mechanism of resistance of red blood cells to granulysin and sensitivity to a subset of granulysin-derived peptides. Granulysin lyses immature reticulocytes, which have mitochondria, but not red blood cells. Granulysin lyses U937 cells but not U937 cells lacking mitochondrial DNA and a functional respiratory chain (U937ρ° cells), further demonstrating the requirement of intact mitochondria for granulysin-mediated death. Peptide G8, which corresponds to helix 2/loop 2/helix 3, lyses red blood cells, while peptide G9, which is identical except that the cysteine residues were replaced by serine, does not lyse red blood cells. Granulysin peptide-induced hemolysis is markedly inhibited by an anion transporter inhibitor and by Na+, K+, and Ca2+channel blockers but not by Na+/K+pump, cotransport, or Cl−channel blockers. Although recombinant granulysin and G9 peptide do not induce hemolysis, they both competitively inhibit G8-induced hemolysis. The finding that some derivatives of granulysin are hemolytic may have important implications for the design of granulysin-based antimicrobial therapeutics.
Glycine-Amide Is an Active Metabolite of the Antiretroviral Tripeptide Glycyl-Prolyl-Glycine-Amide
Authors: Andersson Elin , Horal Peter , Jejcic Alenka , Höglund Stefan , Balzarini Jan , Vahlne Anders , Svennerholm Bo
Published: December 2004

The chemically modified tripeptide glycyl-prolyl-glycine-amide (GPG-NH
2
) inhibits replication of human immunodeficiency virus (HIV) type 1 (HIV-1) in vitro, probably by interfering with capsid formation. The aim of the present study was to determine whether the metabolites glycyl-proline (GP-OH), glycine (G-OH), prolyl-glycine-amide (PG-NH
2
), proline (P-OH), and glycine-amide (G-NH
2
) from proteolytic cleavage may inhibit the replication of HIV-1 in vitro. PG-NH
2
has previously been shown to have a modest effect on HIV-1 replication. In the present study we show that G-NH
2
exhibits a pronounced inhibitory effect on HIV-1. This effect was not due to a decrease in cell proliferation or viability and could not be shown for herpes simplex virus type 1. The G-NH
2
concentration that inhibited virus replication by 50% (IC
50
) was equimolar to that of GPG-NH
2
and ranged from 3 to 41 μM. Transmission electron microscopy revealed that the effect of G-NH
2
on HIV-1 morphology was equivalent to that of GPG-NH
2
and showed disarranged capsid structures, indicating interference with capsid formation. Serial passage of HIV-infected cells with G-NH
2
for more than 20 subcultivations did not decrease the susceptibility to the compound. The results from this study suggest that GPG-NH
2
might act as a prodrug and that G-NH
2
is an active antiretroviral metabolite.
Comparative In Vitro Activities of XRP 2868, Pristinamycin, Quinupristin-Dalfopristin, Vancomycin, Daptomycin, Linezolid, Clarithromycin, Telithromycin, Clindamycin, and Ampicillin against Anaerobic Gram-Positive Species, Actinomycetes, and Lactobacilli
Authors: Goldstein Ellie J. C. , Citron Diane M. , Merriam C. Vreni , Warren Yumi A. , Tyrrell Kerin L. , Fernandez Helen T. , Bryskier Andre
Published: December 2004

A comparative study of the in vitro activities of XRP 2868, a new oral streptogramin, against 266 anaerobic gram-positive clinical isolates using the agar dilution method showed that the XRP 2868 MICs for 95% (254 of 266) of isolates were ≤0.5 μg/ml. XRP 2868 MICs for only two strains, one being
Clostridium clostridioforme
(MIC, 16 μg/ml) and the other being
Clostridium difficile
(MIC, 32 μg/ml), were >2 μg/ml. Depending on its pharmacokinetics and pharmacodynamics, XRP 2868 has potential for use against infections with gram-positive anaerobes and deserves further clinical evaluation.
Comparison of Tn
1546
-Like Elements in Vancomycin-Resistant
Staphylococcus aureus
Isolates from Michigan and Pennsylvania
Authors: Clark Nancye C. , Weigel Linda M. , Patel Jean B. , Tenover Fred C.
Published: December 2004

In 2002, the first two clinical isolates of vancomycin-resistant
Staphylococcus aureus
(VRSA) containing
vanA
were recovered in Michigan and Pennsylvania. Tn
1546
, a mobile genetic element that encodes high-level vancomycin resistance in enterococci, was present in both isolates. With PCR and DNA sequence analysis, we compared the Tn
1546
elements from each isolate to the prototype Tn
1546
element. The Michigan VRSA element was identical to the prototype Tn
1546
element. The Pennsylvania VRSA element showed three distinct modifications: a deletion of nucleotides 1 to 3098 at the 5′ end, which eliminated the
orf1
region; an 809-bp IS
1216V
-like element inserted before nucleotide 3099 of Tn
1546
; and an inverted 1,499-bp IS
1251
-like element inserted into the
vanSH
intergenic region. These differences in the Tn
1546
-like elements indicate that the first two VRSA isolates were the result of independent genetic events.
Antifungal Activities of R-135853, a Sordarin Derivative, in Experimental Candidiasis in Mice
Authors: Kamai Yasuki , Kakuta Masayo , Shibayama Takahiro , Fukuoka Takashi , Kuwahara Shogo
Published: December 2004

The activities of R-135853, a novel sordarin derivative that possesses a 1,4-oxazepane ring moiety, were evaluated in vitro and in vivo. R-135853 exhibited potent in vitro activities against
Candida albicans
(fluconazole-susceptible strains),
Candida glabrata
,
Candida tropicalis
, and
Cryptococcus neoformans
, with MICs at which 90% of isolates were inhibited of 0.03, 1, 0.5, and 0.5 μg/ml, respectively. R-135853 also exhibited potent activities against fluconazole-susceptible dose-dependent and fluconazole-resistant strains of
C. albicans
, with MICs ranging from 0.03 to 0.06 μg/ml. However, R-135853 exhibited weak or no activity against
Candida parapsilosis
,
Candida krusei
, and
Aspergillus
spp. R-135853 exhibited dose-dependent efficacy against experimental murine hematogenous candidiasis induced by
C. albicans
when it was administered by both the subcutaneous and the oral routes and reduced viable cell counts in the kidneys significantly when it was administered at 50 mg/kg of body weight/dose (administration three times a day). In this model, R-135853 also exhibited dose-dependent efficacy by single oral administration. Subcutaneous administration of R-135853 exhibited dose-dependent efficacy against experimental murine esophageal candidiasis induced by fluconazole-resistant
C. albicans
, against which fluconazole at 50 mg/kg/dose was ineffective, and reduced viable cell counts in the esophagus significantly when it was administered at 10 and 50 mg/kg/dose. R-135853 eradicated
C. albicans
from the esophagi of one and four of five mice when it was administered at 10 and 50 mg/kg/dose, respectively. These results suggest that R-135853 is promising for the treatment of disseminated or mucosal candidiasis, including fluconazole-refractory infections.
Induction of Host Matrix Metalloproteinases byBorrelia burgdorferiDiffers in Human and Murine Lyme Arthritis
Authors: Behera Aruna K. , Hildebrand Ethan , Scagliotti Joanna , Steere Allen C. , Hu Linden T.
Published: December 2004

Matrix metalloproteinases (MMPs) are induced from host tissues in response toBorrelia burgdorferi. Upregulation of MMPs may play a role in the dissemination of the organism through extracellular matrix tissues, but it can also result in destructive pathology. Although mice are a well-accepted model for Lyme arthritis, there are significant differences compared to human disease. We sought to determine whether MMP expression could account for some of these differences. MMP expression patterns followingB. burgdorferiinfection were analyzed in primary human chondrocytes, synovial fluid samples from patients with Lyme arthritis, and cartilage tissue from Lyme arthritis-susceptible and -resistant mice by using a gene array, real-time PCR, an enzyme-linked immunosorbent assay, and immunohistochemistry.B. burgdorferiinfection significantly induced transcription of MMP-1, -3, -13, and -19 from primary human chondrocyte cells. Transcription of MMP-10 and tissue inhibitor of metalloprotease 1 was increased withB. burgdorferiinfection, but protein expression was only minimally increased. The synovial fluid levels of MMPs from patients with high and low spirochete burdens were consistent with results seen in the in vitro studies.B. burgdorferi-susceptible C3H/HeN mice infected withB. burgdorferishowed induction of MMP-3 and MMP-19 but no other MMP or tissue inhibitor of metalloprotease. As determined by immunohistochemistry, MMP-3 expression was increased only in chondrocytes near the articular surface. The levels of MMPs were significantly lower in the more Lyme arthritis-resistant BALB/c and C57BL/6 mice. Differences between human and murine Lyme arthritis may be related to the lack of induction of collagenases, such MMP-1 and MMP-13, in mouse joints.
SipA, SopA, SopB, SopD, and SopE2 Contribute toSalmonella entericaSerotype Typhimurium Invasion of Epithelial Cells
Authors: Raffatellu Manuela , Wilson R. Paul , Chessa Daniela , Andrews-Polymenis Helene , Tran Quynh T. , Lawhon Sara , Khare Sangeeta , Adams L. Garry , Bäumler Andreas J.
Published: December 2004

The centisome 63 type III secretion system (T3SS-1) encoded bySalmonellapathogenicity island 1 (SPI1) mediates invasion of epithelial cells bySalmonella entericaserotype Typhimurium. Characterization of mutants lacking individual genes has revealed that T3SS-1 secreted proteins (effectors) SopE2 and SopB are required for invasion while the SipA protein accelerates entry into cells. Here we have revisited the question of which T3SS-1 effectors contribute to the invasion of epithelial cells by complementing a strain lacking all of the effector genes that are required to cause diarrhea in a calf (asipA sopABDE2mutant). Introduction of either the clonedsipA, the clonedsopB, or the clonedsopE2gene increased the invasiveness of thesipA sopABDE2mutant for nonpolarized HT-29 cells. However, a contribution ofsopAorsopDto invasion was not apparent when invasion assays were performed with the nonpolarized colon carcinoma cell lines T84 and HT-29. In contrast, introduction of either thesopA, thesopB, thesopD, or thesopE2gene increased the invasiveness of thesipA sopABDE2mutant for polarized T84 cells. Furthermore, introduction of a plasmid carryingsipAandsopBincreased the invasiveness of thesipA sopABDE2mutant for polarized T84 cells significantly compared to the introduction of plasmids carrying onlysipAorsopB. We conclude that SipA, SopA, SopB, SopD, and SopE2 contribute toS. entericaserotype Typhimurium invasion of epithelial cells in vitro.
SalmonellaPathogenicity Island 2-Mediated Overexpression of Chimeric SspH2 Proteins for Simultaneous Induction of Antigen-Specific CD4 and CD8 T Cells
Authors: Panthel Klaus , Meinel Katrin M. , Domènech Victòria E. Sevil , Retzbach Heike , Igwe Emeka I. , Hardt Wolf-Dietrich , Rüssmann Holger
Published: December 2004

Salmonella entericaserovar Typhimurium employs two different type III secretion systems (TTSS) encoded withinSalmonellapathogenicity islands 1 and 2 (SPI1 and SPI2) for targeting of effector proteins into the cytosol of eukaryotic cells during different stages of the infection cycle. The SPI1 TTSS translocates virulence factors across the plasma membrane when the bacterium initially contacts the host cell. In contrast, the SPI2 TTSS functions to translocate proteins across the membrane of theSalmonella-containing vacuole and promotes intracellular survival and replication. The aim of the present study was to directly compare the potentials of SPI1 and SPI2 type III effector proteins to act as carrier molecules for a heterologous antigen. The p60 protein ofListeria monocytogeneswas used as a model antigen to construct chimeric SopE2 (SPI1), SifA (SPI2), and SspH2 (SPI2) proteins. SPI1- and SPI2-dependent up- and down-regulation of hybrid gene expression led to sequential translocation of p60 fusion proteins into the cytosol ofSalmonella-infected macrophages. Mice orally immunized with recombinantSalmonellastrains expressing these hybrid proteins revealed comparable numbers of p60-specific CD8 T cells. However, only overexpression of translocated SspH2/p60 from a medium-copy-number vector induced simultaneous antigen-specific CD4 and CD8 T-cell responses, suggesting that SspH2 is an attractive carrier molecule for foreign-protein delivery.
Chitinase and Fizz Family Members Are a Generalized Feature of Nematode Infection with Selective Upregulation of Ym1 and Fizz1 by Antigen-Presenting Cells
Authors: Nair Meera G. , Gallagher Iain J. , Taylor Matthew D. , Loke P'ng , Coulson Patricia S. , Wilson R. A. , Maizels Rick M. , Allen Judith E.
Published: December 2004

Ym1 and Fizz1 are secreted proteins that have been identified in a variety of Th2-mediated inflammatory settings. We originally found Ym1 and Fizz1 as highly expressed macrophage genes in aBrugia malayiinfection model. Here, we show that their expression is a generalized feature of nematode infection and that they are induced at the site of infection with both the tissue nematodeLitomosoides sigmodontisand the gastrointestinal nematodeNippostrongylus brasiliensis. At the sites of infection withN. brasiliensis, we also observed induction of other chitinase and Fizz family members (ChaFFs): acidic mammalian chitinase (AMCase) and Fizz2. The high expression of both Ym1 and AMCase in the lungs of infected mice suggests that abundant chitinase production is an important feature of Th2 immune responses in the lung. In addition to expression of ChaFFs in the tissues, Ym1 and Fizz1 expression was observed in the lymph nodes. Expression both in vitro and in vivo was restricted to antigen-presenting cells, with the highest expression in B cells and macrophages. ChaFFs may therefore be important effector or wound-repair molecules at the site of nematode infection, with potential regulatory roles for Ym1 and Fizz1 in the draining lymph nodes.
Interaction and Cellular Localization of the Human Host Defense Peptide LL-37 with Lung Epithelial Cells
Authors: Lau Y. Elaine , Rozek Annett , Scott Monisha G. , Goosney Danika L. , Davidson Donald J. , Hancock Robert E. W.
Published: December 2004

LL-37 is a human cationic host defense peptide that is an essential component of innate immunity. In addition to its modest antimicrobial activity, LL-37 affects the gene expression and behavior of effector cells involved in the innate immune response, although its mode of interaction with eukaryotic cells remains unclear. The interaction of LL-37 with epithelial cells was characterized in tissue culture by using biotinylated LL-37 and confocal microscopy. It was demonstrated that LL-37 was actively taken up into A549 epithelial cells and eventually localized to the perinuclear region. Specific inhibitors were used to demonstrate that the uptake process was not mediated by actin but required elements normally involved in endocytosis and that trafficking to the perinuclear region was dependent on microtubules. By using nonlinear regression analysis, it was revealed that A549 epithelial cells have two receptors for LL-37B, with high and low affinity for LL-37, respectively. These results indicate the mode of interaction of LL-37 with epithelial cells and further our understanding of its role in modulating the innate immune response.
Shiga-Toxigenic
Escherichia coli
-Inoculated Neonatal Piglets Develop Kidney Lesions That Are Comparable to Those in Humans with Hemolytic-Uremic Syndrome
Authors: Pohlenz J. F. , Winter K. R. , Dean-Nystrom E. A.
Published: December 2004

Kidney lesions similar to those in humans with hemolytic-uremic syndrome were observed histologically in 82 of 122 piglets inoculated intragastrically with Shiga-toxigenic
Escherichia coli
but not in 29 controls. The locations of lesions matched locations where Stx-2 binding and Gb3 (globotriasylceramide receptors for Stx) were identified immunohistochemically.
Interleukin-17/Interleukin-17 Receptor-Mediated Signaling Is Important for Generation of an Optimal Polymorphonuclear Response againstToxoplasma gondiiInfection
Authors: Kelly Michelle N. , Kolls Jay K. , Happel Kyle , Schwartzman Joseph D. , Schwarzenberger Paul , Combe Crescent , Moretto Magali , Khan Imtiaz A.
Published: December 2004

We investigated the role of interleukin-17 (IL-17)/IL-17 receptor (IL-17R)-mediated signaling in the protective immunity againstToxoplasma gondii. IL-17R−/−mice developed a normal adaptive immunity against the parasite. However, increased mortality in the knockout animals can be attributed to a defect in the migration of polymorphonuclear leukocytes to infected sites during early infection.
An Immunoreactive 38-Kilodalton Protein of
Ehrlichia canis
Shares Structural Homology and Iron-Binding Capacity with the Ferric Ion-Binding Protein Family
Authors: Doyle C. Kuyler , Zhang Xiaofeng , Popov Vsevolod L. , McBride Jere W.
Published: December 2004

Ehrlichiae are tick-transmitted, gram-negative, obligately intracellular bacteria that live and replicate in cytoplasmic vacuoles, but little is known about iron acquisition mechanisms necessary for their survival. In this study, a genus-conserved immunoreactive ferric ion-binding protein (Fbp) of
Ehrlichia canis
was identified and its iron-binding capability was investigated.
E. canis
Fbp was homologous to a family of periplasmic Fbp's involved in iron acquisition and transport in gram-negative bacteria.
E. canis
Fbp had a molecular mass (38 kDa) consistent with those of Fbp's in other bacteria and exhibited substantial immunoreactivity in its native conformation. The predicted three-dimensional structure of
E. canis
Fbp demonstrated conservation of important Fbp family structural motifs: two domains linked with a polypeptide “hinge” region. Under iron-binding conditions, the recombinant Fbp exhibited an intense red color and an absorbance spectrum indicative of iron binding, and it bound Fe(III) but not Fe(II). Fbp was observed primarily in the cytoplasm of the reticulate forms of
E. canis
and
Ehrlichia chaffeensis
but was notably found on extracellular morula fibers in morulae containing dense-cored organisms. Although expression of Fbp is regulated through an operon of three functionally linked genes in other gram-negative bacteria, the absence of an intact
fbp
operon in
Ehrlichia
spp. suggests that genes involved in ehrlichial iron acquisition have been subject to reductive evolution.
Intercellular Adhesion Molecule 1-Dependent Activation of Interleukin 8 Expression inCandida albicans-Infected Human Gingival Epithelial Cells
Authors: Egusa Hiroshi , Nikawa Hiroki , Makihira Seicho , Jewett Anahid , Yatani Hirofumi , Hamada Taizo
Published: December 2004

Increased induction of interleukin 8 (IL-8) and intercellular adhesion molecule 1 (ICAM-1) by oral epithelial cells may play a role in the host defense mechanism in oropharyngeal candidiasis; however, little is known about the expression feature of these molecules on human gingival epithelial cells (HGECs) duringCandida albicansinfection. In this report we present evidence that neutralization with antibody against ICAM-1 inhibited both the adherence ofC. albicansto HGECs and theCandida-induced production of IL-8, suggesting a role for ICAM-1 in recognition and signaling in HGECs to express IL-8 upon infection withC. albicans.
Chlamydia pneumoniaeEnhances Cytokine-Stimulated Human Monocyte Matrix Metalloproteinases through a Prostaglandin E2-Dependent Mechanism
Authors: Kim Min P. , Gaydos Charlotte A. , Wood Billie Jo , Hardick Justin P. , Zhang Yahong , Wahl Larry M.
Published: December 2004

Exposure of human monocytes toChlamydia pneumoniaeresulted in a significant enhancement of matrix metalloproteinase (MMP) 1 and 9 production following stimulation with tumor necrosis factor alpha and granulocyte monocyte-colony stimulating factor. The effect ofC. pneumoniaeon monocyte MMPs was mediated through the induction of prostaglandin E2. These findings may have implications for atherosclerotic plaque rupture.
Atypical
cpb2
Genes, Encoding Beta2-Toxin in
Clostridium perfringens
Isolates of Nonporcine Origin
Authors: Jost B. Helen , Billington Stephen J. , Trinh Hien T. , Bueschel Dawn M. , Songer J. Glenn
Published: December 2004

Beta2-toxin, encoded by
cpb2
, is implicated in the pathogenesis of
Clostridium perfringens
enteritis. However,
cpb2
genes from nonporcine
C. perfringens
isolates were not always expressed, at least in vitro. Nucleotide sequencing identified atypical
cpb2
genes with 70.2 to 70.7% DNA identity to previously identified (consensus)
cpb2
. Atypical beta2-toxin displayed 62.3% identity and 80.4% similarity to consensus beta2-toxin. No porcine type C isolates (
n
= 16) and only 3.3% of porcine type A isolates (
n
= 60) carried atypical
cpb2
genes. However, 88.5% of nonporcine isolates carried atypical
cpb2
(
n
= 78), but beta2-toxin was not expressed. Almost half of the nonporcine consensus
cpb2
genes (44.4%) carried a frameshift mutation (
n
= 9), resulting in an absence of beta2-toxin expression. These findings strengthen the role of beta2-toxin in the pathogenesis of enteritis in neonatal pigs. However, the identification of apparently nonexpressed, atypical
cpb2
genes raises the question of whether this protein plays the same role in enteritis in other animal species.
Relative Contributions of Innate and Acquired Host Responses to Bacterial Control and Arthritis Development in Lyme Disease
Authors: Wang Xiaohui , Ma Ying , Weis John H. , Zachary James F. , Kirschning Carsten J. , Weis Janis J.
Published: December 2004

TLR2−/−/sciddouble-mutant mice were infected withB. burgdorferito assess the relative importance of acquired and innate host defenses. Although spirochete levels at 4 weeks were lower in TLR2−/−mice than in TLR2−/−/scidmice, the increased arthritis severity of TLR2 (Toll-like receptor 2)-deficient mice was reduced by the presence of thescidmutation.
Transcriptional Adaptation ofShigella flexneriduring Infection of Macrophages and Epithelial Cells: Insights into the Strategies of a Cytosolic Bacterial Pathogen
Authors: Lucchini Sacha , Liu Hong , Jin Qi , Hinton Jay C. D. , Yu Jun
Published: December 2004

Shigella flexneri, the etiologic agent of bacillary dysentery, invades epithelial cells as well as macrophages and dendritic cells and escapes into the cytosol soon after invasion. Dissection of the global gene expression profile of the bacterium in its intracellular niche is essential to fully understand the biology ofShigellainfection. We have determined the complete gene expression profiles forS. flexneriinfecting human epithelial HeLa cells and human macrophage-like U937 cells. Approximately one quarter of theS. flexnerigenes showed significant transcriptional adaptation during infection; 929 and 1,060 genes were up- or down-regulated within HeLa cells and U937 cells, respectively. The keyS. flexnerivirulence genes,ipa-mxi-spaandicsA, were drastically down-regulated during intracellular growth. This theme seems to be common in bacterial infection, because the Ipa-Mxi-Spa-like type III secretion systems were also down-regulated during mammalian cell infection bySalmonella entericaserovar Typhimurium andEscherichia coliO157. The bacteria experienced restricted levels of iron, magnesium, and phosphate in both host cell types, as shown by up-regulation of thesitABCDsystem, themgtAgene, and genes of thephoBRregulon. Interestingly,ydeOand other acid-induced genes were up-regulated only in U937 cells and not in HeLa cells, suggesting that the cytosol of U937 cells is acidic. Comparison with the gene expression of intracellularSalmonellaserovar Typhimurium, which resides within theSalmonella-containing vacuole, indicated thatS. flexneriis exposed to oxidative stress in U937 cells. This work will facilitate functional studies of hundreds of novel intracellularly regulated genes that may be important for the survival and growth strategies ofShigellain the human host.
Complex systems model of fatigue: integrative homoeostatic control of peripheral physiological systems during exercise in humans
Authors: Lambert E V , St Clair Gibson A , Noakes T D
Published: December 2004

Fatigue is hypothesised as being the result of the complex interaction of multiple peripheral physiological systems and the brain. In this new model, all changes in peripheral physiological systems such as substrate depletion or metabolite accumulation act as afferent signallers which modulate control processes in the brain in a dynamic, non-linear, integrative manner.
Obesity: a preventable risk factor for large joint osteoarthritis which may act through biomechanical factors
Authors: Powell A , Teichtahl A J , Wluka A E , Cicuttini F M
Published: December 2004

Osteoarthritis (OA) is a common degenerative disease of joints. The major clinical features are pain and stiffness, leading to a decline in physical function, which may ultimately require joint replacement surgery. As no cure exists, current medical intervention focuses on symptomatic relief. Moreover, as no cure is imminent, preventable risk factors for the onset and progression of the disease are of great interest. Obesity is the main preventable risk factor that has been identified. Given that obesity is modifiable by conservative treatment such as weight loss, its potential importance in reducing the incidence of OA cannot be underestimated.
SOME NEW INTRINSICALLY 3-LINKED GRAPHS
Authors: BOWLIN GARRY , FOISY JOEL
Published: December 2004

In [2], it was shown that every spatial embedding of K10, the complete graph on ten vertices, contains a non-split 3-component link (K10 is intrinsically 3-linked). We improve this result by exhibiting two different subgraphs of K10 that also have this property. In addition, we also exhibit several families of graphs that are intrinsically 3-linked.
Correlation between myocardial malate/aspartate shuttle activity and EAAT1 protein expression in hyper- and hypothyroidism
Authors: Ralphe J. Carter , Bedell Kurt , Segar Jeffrey L. , Scholz Thomas D.
Published: December 2004

In the heart, elevated thyroid hormone leads to upregulation of metabolic pathways associated with energy production and development of hypertrophy. The malate/aspartate shuttle, which transfers cytosolic-reducing equivalents into the cardiac mitochondria, is increased 33% in hyperthyroid rats. Within the shuttle, the aspartate-glutamate carrier is rate limiting. The excitatory amino acid transporter type 1 (EAAT1) functions as a glutamate carrier in the malate/aspartate shuttle. In this study, we hypothesize that EAAT1 is regulated by thyroid hormone. Adult rats were injected with triiodothyronine (T3) or saline over a period of 8–9 days or provided with propylthiouracil (PTU) in their drinking water for 2 mo. Steady-state mRNA levels of EAAT1 and aralar1 and citrin (both cardiac mitochondrial aspartate-glutamate transporters) were determined by Northern blot analysis and normalized to 18S rRNA. A spectrophotometric assay of maximal malate/aspartate shuttle activity was performed on isolated cardiac mitochondria from PTU-treated and control animals. Protein lysates from mitochondria were separated by SDS-PAGE and probed with a human anti-EAAT1 IgG. Compared with control, EAAT1 mRNA levels (arbitrary units) were increased nearly threefold in T3-treated (3.1 ± 0.5 vs. 1.1 ± 0.2; P < 0.05) and decreased in PTU-treated (2.0 ± 0. 3 vs. 5.2 ± 1; P < 0.05) rats. Aralar1 mRNA levels were unchanged in T3-treated and somewhat decreased in PTU-treated (7.1 ± 1.0 vs. 9.3 ± 0.1, P < 0.05) rats. Citrin mRNA levels were decreased in T3-treated and unchanged in PTU-treated rats. EAAT1 protein levels (arbitrary units) in T3-treated cardiac mitochondria were increased compared with controls (8.9 ± 0.4 vs. 5.9 ± 0.6; P < 0.005) and unchanged in PTU-treated mitochondria. No difference in malate/aspartate shuttle capacity was found between PTU-treated and control cardiac mitochondria. Hyperthyroidism in rats is related to an increase in cardiac expression of EAAT1 mRNA and protein. The 49% increase in EAAT1 mitochondrial protein level shows that malate/aspartate shuttle activity increased in hyperthyroid rat cardiac mitochondria. Although hypothyroidism resulted in a decrease in EAAT1 mRNA, neither the EAAT1 protein level nor shuttle activity was affected. EAAT1 regulation by thyroid hormone may facilitate increased metabolic demands of the cardiomyocyte during hyperthyroidism and impact cardiac function in hyperthyroidism.
Localization and modulation of α1D (Cav1.3) L-type Ca channel by protein kinase A
Authors: Qu Yongxia , Baroudi Ghayath , Yue Yuankun , El-Sherif Nabil , Boutjdir Mohamed
Published: December 2004

α1D L-type Ca channel was assumed to be of neuroendocrine origin only; however, α1D L-type Ca channel knockout mice exhibit sinus bradycardia and atrioventricular block, indicating a distinct role of α1D in the heart. The presence and distribution of α1D Ca channel in the heart and its regulation by protein kinase A (PKA) are just emerging. Our objective was to examine the localization of α1D L-type Ca channel in rabbit and rat hearts and its modulation by PKA. Here, we show the exclusive presence of α1D Ca channel transcript in the sinoatrial node, atrioventricular node, and atria but not in the ventricle by RT-PCR and the expression of α1D Ca channel protein in atrial myocytes' sarcolemma by indirect immunostaining and Western blot. There is no significant difference in the expression level of α1D Ca channel in the left versus right atrium. Superfusion of membrane-permeable 8-bromo-cAMP resulted in a significant increase of the peak current density of α1D Ca current expressed in tsA201 cells. This increase was inhibited by the PKA inhibitor (PKI). Application of 8-bromo-cAMP also readily phosphorylated the α1D Ca channel protein. The results are first to demonstrate that PKA phosphorylation of L-type Ca channel α1D-subunit resulted in an increase of the α1D Ca channel activity. Together with the observation that α1D Ca channel is exclusively present in the sinoatrial node and atria, the findings suggest that α1D Ca channel plays a unique role in the sinoatrial tissue and is a target for sympathetic control of heart rhythm.
Acetaminophen-sensitive prostaglandin production in rat cerebral endothelial cells
Authors: Kis Bela , Snipes James A. , Simandle Steve A. , Busija David W.
Published: December 2004

Acetaminophen is a widely used antipyretic and analgesic drug whose mechanism of action has recently been suggested to involve inhibitory effects on prostaglandin synthesis via a newly discovered cyclooxygenase variant (COX-3). Because COX-3 expression is high in cerebral endothelium, we investigated the effect of acetaminophen on the prostaglandin production of cultured rat cerebral endothelial cells (CECs). Acetaminophen dose-dependently inhibited both basal and LPS-induced PGE2 production in CECs with IC50 values of 15.5 and 6.9 μM, respectively. Acetaminophen also similarly inhibited the synthesis of 6-keto-PGF1α and thromboxane B2. LPS stimulation increased the expression of COX-2 but not COX-1 or COX-3. In addition, the selective COX-2 inhibitor NS398 (1 μM) was equally as effective as acetaminophen in blocking LPS-induced PGE2 production. Acetaminophen did not influence the expression of the three COX isoforms and the inducible nitric oxide synthase. In LPS-stimulated isolated cerebral microvessels, acetaminophen also significantly inhibited PGE2 production. Our results show that prostaglandin production in CECs during basal and stimulated conditions is very sensitive to inhibition by acetaminophen and suggest that acetaminophen acts against COX-2 and not COX-1 or COX-3. Furthermore, our findings support a critical role for cerebral endothelium in the therapeutic actions of acetaminophen in the central nervous system.
Constructing Banaschewski compactification without Dedekind completeness axiom
Authors: Acharyya S. K. , Chattopadhyay K. C. , Ghosh Partha Pratim
Published: December 2004

The main aim of this paper is to provide a construction of the Banaschewski compactification of a zero‐dimensional Hausdorff topological space as a structure space of a ring of ordered
field‐valued continuous functions on the space, and thereby exhibit the independence of the construction from any
completeness axiom for an ordered field. In the process of describing this construction we have generalized the classical versions of M. H. Stone′s theorem, the Banach‐Stone theorem, and
the Gelfand‐Kolmogoroff theorem. The paper is concluded with a conjecture of a split in the class of all
zero‐dimensional but not strongly zero‐dimensional Hausdorff topological spaces into three classes that are labeled by
inequalities between three compactifications of X, namely, the
Stone‐Čech compactification βX, the Banaschewski
compactification β0X, and the structure space
𝔐X,F of the lattice‐ordered commutative ring ℭ(X, F) of all continuous functions on X taking values in the ordered
field F, equipped with its order topology. Some open problems
are also stated.
Justification of the existence of a group of asymptotics of the general fifth Painlevé transcendent
Authors: Lu Youmin , Shao Zhoude
Published: December 2004

There are several existing ways in developing the asymptotics of
the Painlevé transcendents. But it is always a hard task to
justify the existence of these asymptotics. In this note, we
apply the successive approximation to the general fifth
Painlevé equation and rigorously prove the existence of a
group of asymptotics of its solutions.
On the Lagrange resolvents of a dihedral quintic polynomial
Authors: Spearman Blair K. , Williams Kenneth S.
Published: December 2004

The cyclic quartic field generated by the fifth powers of the
Lagrange resolvents of a dihedral quintic polynomial f(x) is explicitly determined in terms of a generator for the quadratic
subfield of the splitting field of f(x)
.
The English literature researcher in the age of the Internet
Authors: Ellis David , Oldman Hanna
Published: December 2004

This study explores the extent to which the information seeking behaviour of researchers active in the field of English Literature in the universities of the UK and the wider world has changed as a result of the developing electronic information revolution. It deals with the researchers’ attitudes towards the Internet and examines their position with regard to utilizing the Internet as a publication outlet. The different types of electronic information sources for English literature are identified and the experiences of researchers using them explored. Finally, the study examines researcher attitudes towards electronic publication and to plans for a `virtual library’. The article concludes with recommendations for further study of the use of electronic resources in relation to information literacy and browsing and other facilities for subject access on the Internet.
Managing IT projects: communication pitfalls and bridges
Authors: Gillard Sharlett
Published: December 2004

The complex nature of the matrix organizational structure presents a communication paradigm unparalled by any other management position, creating an organizational environment that is uniquely sensitive to interpersonal communications. This paper discusses the organizational environment typically found in major information systems initiatives as well as some of the interpersonal communications challenges encountered by the IT project manager. Suggestions are provided as bridges to avoid the pitfalls these challenges present.
Evolution of virtual libraries in Nigeria: myth or reality?
Authors: Ani Okon E.
Published: December 2004

The article investigates factors that may make the Nigeria Virtual Library Project a myth or reality. Questionnaires were used for data collection, using 22 University Librarians in federal universities as respondents, and 14 (64%) University Librarians completed the questionnaires. Three indicators were used to determine the myth or reality of evolving virtual libraries in Nigeria: availability of information infrastructures, human capacity building programmes in ICT, and level of funding of university libraries. Nine (64%) of the libraries have relevant information infrastructures, 12 (86%) are involved in human capacity building programmes, 11 (79%) affirm that the level of funding for university libraries is low. The article concludes that evolution of virtual libraries is feasible and real in Nigeria.
Globalization, Liberalization, and Prospects for the State
Authors: Putzel James
Published: December 2004

Patterns of globalization and liberalization need to be examined in light of their political consequences, especially in the context of situations of state collapse and violent conflict. Champions of globalization can be divided into two camps – the advocates of economic liberalization and the promoters of global governance. They share a common skepticism of the state, which ignores both the developmental lessons of history and the perverse impact liberalization has had on peace and security. While liberalization has transformed the terrain of politics, privileging a form of semi-democracy, problems of violent conflict highlight the urgent need for the reconstitution of modern states in the developing world.
Liberalization and Conflict
Authors: Keen David
Published: December 2004

Externally encouraged policies of liberalization in Sierra Leone in the 1970s and 1980s fed into civil war in the 1990s; yet such policies are now being revived. This article analyzes the impact of liberalization on the war in Sierra Leone, suggesting that it affected the conflict in four ways: first, by encouraging inflation, extreme devaluation, and private oligopolies; second, by reducing key state services such as education and health; third, by fueling corruption as real state salaries were cut; and fourth, by taking attention away from soldiers’ abuses under the military government of 1992–96, a government that was praised and rewarded for its liberalization agenda.
Economic Liberalization, Political Instability, and State Capacity in Venezuela
Authors: Di John Jonathan
Published: December 2004

This article examines the mechanisms through which economic liberalization policies contributed to increasing political instability and declines in state capacity in Venezuela. Particular attention is paid to the role that increasing income inequality played in polarizing politics and the role that policy switches and party-neglecting strategies among reformers played in increasing political instability. The Venezuelan experience challenges the mainstream view of state capacity, which posits that reductions in the state’s discretionary control over resources will reduce corruption, and thereby increase the capacity of the state to govern more effectively. It also examines why Venezuela suffered greater destabilization than other Latin American economies undergoing neoliberal reform.
Local embeddedness in a global world
Authors: O’Connor Pat
Published: December 2004

This paper is concerned with exploring issues related to local embeddedness. It is based on material provided by a national sample of young people aged 10-12 years and 14-17 years who were invited to write a single page about their lives and the future. Approximately 34,000 young people did so within a school context. The paper is based on a quantitative and qualitative content analysis of a stratified random sample of 4100 of these texts. Firstly it looks at the significance and meaning of the local area. Secondly it looks at their life styles as contexts for the relationship between the global and the local, focusing particularly on those related to media and to sporting activities. The paper concludes by noting that although many aspects of young people’s lives draw on global products, the young people remain deeply embedded within local contexts structured by age and gender.
Zero confidence in youths?
Authors: Korander Timo , Törrönen Jukka
Published: December 2004

The article describes a zero tolerance project carried out between August 1999 and July 2000 in Tampere, Finland. Specifically, the authors are interested in the reception of the project among field workers as well as the main targets of the intervention. The project received considerable media exposure. Initially, the objectives of the project were to reduce the occurrence of violence, vandalism, substance use and disorderly behaviour in the town centre. Project management stressed from the outset that zero tolerance would not be applied to young people alone. However as soon as the project got under way, senior police officers and the media came to describe this as a campaign aimed at containing disruptive behaviour by young people and at getting parents and the local community involved in shouldering part of the responsibility. The data consist of interviews with police officers who worked in the field, social workers and young people. Our study goes to show that a lowered level of tolerance can have unwanted and uncontrollable consequences. The project strengthened the feeling of solidarity between adults but increased the lack of confidence between adults and young people.
Young mothers with special educational needs
Authors: Myklebust Jon Olav , Solvang Brynhild
Published: December 2004

A Norwegian longitudinal study of approximately 500 adolescents with special educational needs documents that many of the women have had a child at a young age. In a follow-up interview the experiences of a small sample of these women are recorded. Methodologically, a narrative approach has been chosen, and the women’s stories are interpreted from a life course perspective with an emphasis on transitions and turning points. The analysis reveals the salience of family relations in the handling of critical transitions, but it also demonstrates how important individual agency is for adolescents facing challenging situations in the transition to adulthood.
Jipis, Pijos, Fiesteros
Authors: Pàmpols Carles Feixa , Porzio Laura
Published: December 2004

This text is an attempt to review academic work on youth cultures carried out in Spain since the transition to democracy (although some earlier work related to the subject, stemming from the late Franco period, is also discussed). The nearly 200 contributions analysed (books, papers, theses, unpublished reports and journal texts) were grouped into different academic areas such as criminology, sociology, psychology, communication or anthropology, and theoretical trends ranging from ‘edifying’ ecclesiastic postwar literature to the Birmingham school.The works are classified into five major periods marked by different youth styles which act as distorting mirrors of social and cultural changes that are taking place: the late Franco times ( golfos and jipis), the transition to democracy ( punkis and progres), the post-transition ( pijos and makineros), the 1990s ( okupas and pelaos) and the present time ( fiesteros and alternativos) (see Glossary to Spanish terms).The social context, the academic framework and the main research lines for these periods are analysed, and the authors also touch upon what they consider as representative of the emerging ideological, theoretical and methodological tendencies.
Executive functions in children with communication impairments, in relation to autistic symptomatology
Authors: Bishop Dorothy V. M. , Norbury Courtenay Frazier
Published: December 2004

Previous research has found that people with autism generate few novel responses in ideational fluency tasks, and it has been suggested this deficit is a specific correlate of stereotyped/repetitive behavior. We assessed generativity in children with pragmatic language impairment (PLI) who showed communicative abnormalities resembling those seen in autism. We compared four groups: high-functioning autism; PLI; specific language impairment; and control. Generativity was measured using two fluency tasks previously shown to be sensitive to autistic disorder. Correlational analysis revealed a significant relationship between the percentage of correct responses on the fluency tasks and measures of communicative abnormality. It is often assumed that pragmatic difficulties are caused by limitations of social cognition. This study suggests that difficulties in generating relevant ideas can be another cause of autistic-like communicative abnormalities.
Interaction and imitation deficits from infancy to 4 years of age in children with autism
Authors: Receveur Christine , Lenoir Pascal , Desombre Hugues , Roux Sylvie , Barthelemy Catherine , Malvy Joëlle
Published: December 2004

The present study investigated the influence of developmental level on interaction and imitation in infants and young children with autism on the basis of family videos and filmed consultation. The sample comprised 18 children with autism divided into groups according to their developmental quotient (DQ > 50 and DQ < 50). A quantitative evaluation was performed on video observations at four periods (10-12 months, 16-18 months, 24-26 months, after 4 years) using scales appropriate for the evaluation of interaction and imitation impairments. The findings showed that, at a very early age, infants later diagnosed as having autistic disorder show different intensities of interaction and imitation deficits according to developmental level.