bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and Characterization ofNeospora caninumCyclophilin That Elicits Gamma Interferon Production
Authors: Tuo Wenbin , Fetterer Raymond , Jenkins Mark , Dubey J. P.
Published: July 2005

Gamma interferon (IFN-γ) response is essential to the development of a host protective immunity in response to infections by intracellular parasites. Neosporosis, an infection caused by the intracellular protozoan parasiteNeospora caninum, is fatal when there is a complete lack of IFN-γ in the infected host. However, the mechanism by which IFN-γ is elicited by the invading parasite is unclear. This study has identified a microbial protein in theN. caninumtachyzoiteN. caninumcyclophilin (NcCyP) as a major component of the parasite responsible for the induction of IFN-γ production by bovine peripheral blood mononuclear cells (PBMC) and antigen-specific CD4+T cells. NcCyP has high sequence homology (86%) withToxoplasma gondii18-kDa CyP with a calculated molecular mass of 19.4 kDa. NcCyP is a secretory protein with a predicted signal peptide of 17 amino acids. Abundant NcCyP was detected in whole-cellN. caninumtachyzoite lysate antigen (NcAg) andN. caninumtachyzoite culture supernatant. InN. caninumtachyzoite culture supernatant, three NcCyP bands of 19, 22, and 24 kDa were identified. NcAg stimulated high levels of IFN-γ production by PBMC and CD4+T cells. The IFN-γ-inducing effect of NcAg was blocked by cyclosporine, a specific ligand for CyP, in a dose-dependent manner. Furthermore, cyclosporine abolished IFN-γ production by PBMC from naïve cows as well as PBMC and CD4+T cells from infected/immunized cows. These results indicate that theN. caninumtachyzoite naturally produces a potent IFN-γ-inducing protein, NcCyP, which may be important for parasite survival as well as host protection.
Inter-Alpha-Inhibitor Proteins Are Endogenous Furin Inhibitors and Provide Protection against Experimental Anthrax Intoxication
Authors: Opal Steven M. , Artenstein Andrew W. , Cristofaro Patricia A. , Jhung Jhung W. , Palardy John E. , Parejo Nicholas A. , Lim Yow-Pin
Published: July 2005

Inter-alpha-inhibitor protein (IαIp) functions as an endogenous serine protease inhibitor in human plasma, and IαIp levels diminish rapidly during acute inflammatory states. One potential target for IαIp is furin, a cell-associated serine endopeptidase essential for the activation of protective antigen and the formation of anthrax lethal toxin (LT). IαIp blocks furin activity in vitro and provides significant protection against cytotoxicity for murine peritoneal macrophages exposed to up to 500 ng/ml LT. A monoclonal antibody (MAb), 69.31, that specifically blocks the enzymatic activity of IαIp eliminates its protective effect against LT-induced cytotoxicity. IαIp (30 mg/kg of body weight) administered to BALB/c mice 1 hour prior to an intravenous LT challenge resulted in 71% survival after 7 days compared with no survivors among the control animals (P< 0.001). We conclude that human IαIp may be an effective preventative or therapeutic agent against anthrax intoxication.
Establishment of Cloned
Anaplasma phagocytophilum
and Analysis of
p44
Gene Conversion within an Infected Horse and Infected SCID Mice
Authors: Lin Quan , Rikihisa Yasuko
Published: July 2005

Diverse
p44
alleles at the
p44
expression locus (
p44E
s) encoding surface-exposed major membrane proteins, P44s, of
Anaplasma phagocytophilum
were hypothesized to be garnered by recombination to enact antigenic variation. However, this hypothesis has not been proven so far, due to inability to clone this obligate intragranulocytic rickettsia. To define the
p44E
recombination, we developed a novel method to clone
A. phagocytophilum
. This isogenic cloned population containing a defined
p44E
was used to infect a naive horse and severe combined immunodeficiency (SCID) mice. During a 58-day infection period in the blood of the horse,
p44E
conversion was evident in a total of 11 new
p44E
s, 48% (115/242) of the sequenced
p44E
population. During a 50-day infection period in the blood of SCID mice,
p44E
conversion was manifested in a total of 13 new
p44E
s, 42% (192/460) of the
p44E
population. Thus, similar levels of
p44E
convertants were detected in either the presence or absence of an acquired immune system, suggesting that T- and B-cell immune pressure was not essential for recombination and/or selection of the
p44E
variants. Analysis of sequentially changed
p44E
s revealed that the entire central hypervariable region of donor
p44
pseudogenes or of donor full-length
p44
s replaced the same region of the resident
p44E
as a cassette. Putative recombination points were detected within
p44
conserved regions flanking the central hypervariable region by the TOPALi analysis. Our results unambiguously demonstrated
p44E
recombination. The cloning method developed would facilitate precise analysis of the recombination process and the extent of diversity which the recombination creates in the antigenic repertoire.
Shiga Toxin 1 Induces Apoptosis in the Human Myelogenous Leukemia Cell Line THP-1 by a Caspase-8-Dependent, Tumor Necrosis Factor Receptor-Independent Mechanism
Authors: Lee Sang-Yun , Cherla Rama P. , Caliskan Isa , Tesh Vernon L.
Published: July 2005

Shiga toxins (Stxs) induce apoptosis in a variety of cell types. Here, we show that Stx1 induces apoptosis in the undifferentiated myelogenous leukemia cell line THP-1 in the absence of tumor necrosis factor alpha (TNF-α) or death receptor (TNF receptor or Fas) expression. Caspase-8 and -3 inhibitors blocked, and caspase-6 and -9 inhibitors partially blocked, Stx1-induced apoptosis. Stx1 induced the mitochondrial pathway of apoptosis, as activation of caspase-8 triggered the (i) cleavage of Bid, (ii) disruption of mitochondrial membrane potential, and (iii) release of cytochromecinto the cytoplasm. Caspase-8, -9, and -3 cleavage and functional activities began 4 h after toxin exposure and peaked after 8 h of treatment. Caspase-6 may also contribute to Stx1-induced apoptosis by directly acting on caspase-8. It appears that functional Stx1 holotoxins must be transported to the endoplasmic reticulum to initiate apoptotic signaling through the ribotoxic stress response. These data suggest that Stxs may activate monocyte apoptosis via a novel caspase-8-dependent, death receptor-independent mechanism.
Hag Directly Mediates the Adherence ofMoraxella catarrhalisto Human Middle Ear Cells
Authors: Bullard Brian , Lipski Serena L. , Lafontaine Eric R.
Published: July 2005

Moraxella catarrhalisis a human pathogen that causes otitis media in young children and lung infections in patients with chronic obstructive pulmonary disease. In this study, the role of the surface protein Hag in the adherence of multipleM. catarrhalisstrains was examined. Thehaggenes of four clinical isolates were disrupted with a spectinomycin resistance cassette, and the binding of isogenic mutants to primary cultures of human middle ear epithelial cells (HMEE), as well as A549 pneumocytes, was measured. These experiments revealed that the attachment of most mutants to both cell types was 10-fold less than that of their wild-type progenitors. To determine whether Hag directly mediates adherence to human cells, thehaggenes from threeM. catarrhalisisolates were cloned and expressed in a nonadherentEscherichia colicloning strain. At least 17-fold moreE. colibacteria expressing Hag attached to HMEE cells than an adherence-negative control. Surprisingly, Hag expression did not increase the binding of recombinantE. colito A549 monolayers. Our data demonstrate that the involvement of Hag inM. catarrhalisadherence to A549 and HMEE cells is conserved among isolates and that Hag directly mediates binding to HMEE cells.
MyD88, but Not Toll-Like Receptors 4 and 2, Is Required for Efficient Clearance ofBrucella abortus
Authors: Weiss David S. , Takeda Kiyoshi , Akira Shizuo , Zychlinsky Arturo , Moreno Edgardo
Published: July 2005

It is not clear how the host initially recognizes and responds to infection by gram-negative pathogenicBrucellaspp. It was previously shown (D. S. Weiss, B. Raupach, K. Takeda, S. Akira, and A. Zychlinsky, J. Immunol. 172:4463-4469, 2004) that the early macrophage response against gram-negative bacteria is mediated by Toll-like receptor 4 (TLR4), which signals in response to lipopolysaccharide (LPS).Brucella, however, has a noncanonical LPS which does not have potent immunostimulatory activity. We evaluated the kinetics of TLR4 activation and the cytokine response in murine macrophages afterBrucellainfection. We found that during infection of macrophages,Brucellaavoids activation of TLR4 at 6 h but activates TLR4, TLR2, and myeloid differentiation factor 88 (MyD88) at 24 h postinfection. Interestingly, even though its activation is delayed, MyD88 is important for host defense againstBrucellainfection in vivo, since MyD88−/−mice do not clear the bacteria as efficiently as wild-type, TLR4−/−, TLR2−/−, or TLR4/TLR2−/−mice.
4-1BB (CD137) Is Required for Rapid Clearance ofListeria monocytogenesInfection
Authors: Lee Sang-C. , Ju Seong-A. , Pack Ha-N. , Heo Sook-K. , Suh Jae-H. , Park Sang-M. , Choi Boem-K. , Kwon Byoung S. , Kim Byung S.
Published: July 2005

4-1BB (CD137), a member of the tumor necrosis factor receptor superfamily, is a T-cell-costimulatory receptor that is expressed on activated T cells, dendritic cells, and NK cells. Little has been reported about its role in early host defense against bacterial infection. In this study, we report that 4-1BB-deficient (4-1BB−/−) mice are much more susceptible toListeria monocytogenes(intracellular bacteria) infections than wild-type mice. UponL. monocytogenesinfection, 4-1BB−/−mice showed a lower survival rate, a higher bacterial burden in organs, and larger hepatic microabscesses than 4-1BB+/+mice. 4-1BB−/−mice also had impairment in clearance of bacteria from the bloodstream. Neutrophils from 4-1BB+/+mice constitutively expressed 4-1BB, which could be activated to induce intracellular Ca2+influx by ligation with anti-4-1BB antibody. On the other hand, neutrophils from 4-1BB−/−mice were defective in reactive oxygen species generation, phagocytic activities, and intracellular Ca2+mobilization. In addition, mice pretreated with anti-4-1BB monoclonal antibody were much more resistant toL. monocytogenesinfection than control antibody-treated mice. Our results support the notion that 4-1BB may play a major role in host defense against intracellular pathogens through neutrophil activation.
Experimental Ocular Toxoplasmosis in Genetically Susceptible and Resistant Mice
Authors: Lu Fangli , Huang Shiguang , Hu Mark S. , Kasper Lloyd H.
Published: July 2005

Genetic factors determining the pathogenesis and course of ocular toxoplasmosis are poorly understood. In this study, we explored the development of experimental ocular pathogenesis in genetically dissimilar mice infected with either the RH strain, the PLK strain, or the immunodominant surface antigen 1 (SAG1 [P30])-deficient mutant of the RH strain ofToxoplasma gondii. At 11 days postinfection, ocular infection of C57BL/6 mice with all of the strains of parasites resulted in severe inflammatory lesions and high numbers of parasites in eye tissue; less severe ocular lesions at earlier histopathology and prolonged survival were observed in this mouse strain infected with either the major surface antigen 1-deficient SAG1−/−strain or the less virulent PLK strain compared with RH infection. In contrast, both BALB/c and CBA/J mice had less severe lesions and low numbers of parasites in their eye tissue, and infection developed into the chronic stage in these mice. There were significantly higher serum levels of gamma interferon and tumor necrosis factor alpha in C57BL/6 mice than in BALB/c and CBA/J mice following ocular infection. These observations confirm earlier reports on systemic immunity to these parasites that the route ofToxoplasmainfection markedly influences survival of mice. Our data indicate that genetic factors of the host as well as the parasite strain are critical in determining susceptibility to experimental ocular toxoplasmosis in murine models.
Production and Characterization of Monoclonal Antibodies against
Enterocytozoon bieneusi
Purified from Rhesus Macaques
Authors: Zhang Quanshun , Singh Inderpal , Sheoran Abhineet , Feng Xiaochuan , Nunnari John , Carville Angela , Tzipori Saul
Published: July 2005

Enterocytozoon bieneusi
spores derived from rhesus macaque feces were purified by serial salt-Percoll-sucrose-iodixanol centrifugation, resulting in two bands with different specific densities of 95.6% and 99.5% purity and with a recovery efficiency of 10.8%. An ultrastructural examination revealed typical
E. bieneusi
spores. Twenty-six stable hybridomas were derived from BALB/c mice immunized with spores and were cloned twice by limiting dilution or growth on semisolid medium. Four monoclonal antibodies (MAbs), reacting exclusively with spores, were further characterized. These MAbs specifically reacted with spores present in stools of humans and macaques, as visualized by immunofluorescence, and with spore walls, as visualized by immunoelectron microscopy. A blocking enzyme-linked immunosorbent assay and Western blotting revealed that the epitope recognized by 8E2 was different from those recognized by 7G2, 7H2, and 12G8, which identified the same 40-kDa protein. These MAbs will be valuable tools for diagnostics, for epidemiological investigations, for host-pathogen interaction studies, and for comparative genomics and proteomics.
Probiotics Reduce Enterohemorrhagic
Escherichia coli
O157:H7- and Enteropathogenic
E. coli
O127:H6-Induced Changes in Polarized T84 Epithelial Cell Monolayers by Reducing Bacterial Adhesion and Cytoskeletal Rearrangements
Authors: Sherman Philip M. , Johnson-Henry Kathene C. , Yeung Helen P. , Ngo Peter S. C. , Goulet Jacques , Tompkins Thomas A.
Published: July 2005

The aim of this study was to determine if probiotics reduce epithelial injury following exposure to
Escherichia coli
O157:H7 and
E. coli
O127:H6. The pretreatment of intestinal (T84) cells with lactic acid-producing bacteria reduced the pathogen-induced drop in transepithelial electrical resistance. These findings demonstrate that probiotics prevent epithelial injury induced by attaching-effacing bacteria.
Factors Associated with Severe Granulomatous Pneumonia inMycobacterium tuberculosis-Infected Mice Vaccinated Therapeutically with hsp65 DNA
Authors: Taylor Jennifer L. , Ordway Diane J. , Troudt JoLynn , Gonzalez-Juarrero Mercedes , Basaraba Randall J. , Orme Ian M.
Published: July 2005

Resistant C57BL/6 mice infected in the lungs withMycobacterium tuberculosisand then therapeutically vaccinated withMycobacterium leprae-derived hsp65 DNA develop severe granulomatous pneumonia and tissue damage. Analysis of cells accumulating in the lungs of these animals revealed substantial increases in T cells secreting tumor necrosis factor alpha and CD8 cells staining positive for granzyme B. Stimulation of lung cells ex vivo revealed very high levels of interleukin-10, some of which was produced by B-1 B cells. This was probably an anti-inflammatory response, since lung pathology was dramatically worsened in B-cell gene-disrupted mice.
Intracellular Survival of
Campylobacter jejuni
in Human Monocytic Cells and Induction of Apoptotic Death by Cytholethal Distending Toxin
Authors: Hickey Thomas E. , Majam Gary , Guerry Patricia
Published: July 2005

Campylobacter jejuni
81-176 is capable of extensive replication within human monocytic cell vacuoles and induces apoptotic death via cytolethal distending toxin.
Biofilm Formation by
Salmonella enterica
Serovar Typhimurium and
Escherichia coli
on Epithelial Cells following Mixed Inoculations
Authors: Esteves Cristina L. C. , Jones Bradley D. , Clegg Steven
Published: July 2005

Biofilms were formed by inoculations of
Salmonella enterica
serovar Typhimurium and
Escherichia coli
on HEp-2 cells. Inoculations of
S. enterica
serovar Typhimurium and
E. coli
resulted in the formation of an extensive biofilm of
S. enterica
serovar Typhimurium. In experiments where an
E. coli
biofilm was first formed followed by challenge with
S. enterica
serovar Typhimurium, there was significant biofilm formation by
S. enterica
serovar Typhimurium. The results of this study indicate that
S. enterica
serovar Typhimurium can outgrow
E. coli
in heterologous infections and displace
E. coli
when it forms a biofilm on HEp-2 cells.
Virulence Comparisons of
Aspergillus nidulans
Mutants Are Confounded by the Inflammatory Response of p47

phox

−/−
Mice
Authors: Bignell Elaine , Negrete-Urtasun Susana , Calcagno Ana Maria , Arst Herbert N. , Rogers Tom , Haynes Ken
Published: July 2005

While investigating the requirement for phagosomal alkalinization in the host defense against pulmonary aspergillosis, we observed high morbidity of p47

phox

−/−
mice infected with pH-insensitive
Aspergillus nidulans
mutants despite a paucity of fungal growth. Fatal infection also resulted from a normally avirulent
p
-aminobenzoate auxotroph. This demonstrates that p47

phox

−/−
murine immunity contributes significantly to
A. nidulans
lethality. These data have wider implications for microbial virulence studies with p47

phox

−/−
mice.
Identification of Variant-Specific Surface Proteins in
Giardia muris
Trophozoites
Authors: Ropolo Andrea S. , Saura Alicia , Carranza Pedro G. , Lujan Hugo D.
Published: July 2005

Giardia lamblia
undergoes antigenic variation, a process that might allow the parasite to evade the host's immune response and adapt to different environments. Here we show that
Giardia muris
, a related species that naturally infects rodents, possesses multiple variant-specific surface proteins (VSPs) and expresses VSPs on its surface, suggesting that it undergoes antigenic variation similar to that of
G. lamblia
.
Importance of
srtA
and
srtB
for Growth of
Bacillus anthracis
in Macrophages
Authors: Zink Steven D. , Burns Drusilla L.
Published: July 2005

We examined the effect of mutation of two sortase genes of
Bacillus anthracis
,
srtA
and
srtB
, on the ability of the bacterium to grow in J774A.1 cells, a mouse macrophage-like cell line. While disruption of either
srtA
or
srtB
had no effect on the ability of the bacteria to grow in rich culture media, mutations in each of these genes dramatically attenuated growth of the bacterium in J774A.1 cells. Complementation of the mutation restored the ability of bacteria to grow in the cells. Since the initial events in inhalation anthrax are believed to be uptake of
B. anthracis
spores by alveolar macrophages followed by germination of the spores and growth of the bacteria within the macrophages, these results suggest that two sortases of
B. anthracis
may be critical in the early stages of inhalation anthrax.
Characterization of a Humanized Monoclonal Antibody Recognizing Clumping Factor A Expressed by
Staphylococcus aureus
Authors: Domanski Paul J. , Patel Pratiksha R. , Bayer Arnold S. , Zhang Li , Hall Andrea E. , Syribeys Peter J. , Gorovits Elena L. , Bryant Dawn , Vernachio John H. , Hutchins Jeff T. , Patti Joseph M.
Published: July 2005

We report the humanization and characterization of monoclonal antibody (MAb) T1-2 or tefibazumab, a monoclonal antibody that recognizes clumping factor A expressed on the surface of
Staphylococcus aureus
. We demonstrate that the binding kinetics of MAb T1-2 is indistinguishable compared to that of its murine parent. Furthermore, MAb T1-2 is shown to enhance the opsonophagocytic uptake of ClfA-coated latex beads, protect against an intravenous challenge in a prophylactic model of rabbit infective endocarditis, and enhance the efficacy of vancomycin therapy in a therapeutic model of established infective endocarditis.
Mapping of the Binding Site for
Mannheimia haemolytica
Leukotoxin within Bovine CD18
Authors: Dileepan T. , Kannan M. S. , Walcheck B. , Thumbikat P. , Maheswaran S. K.
Published: July 2005

To map the site involved in
Mannheimia haemolytica
leukotoxin (LktA) binding and biological activity within bovine CD18, bovine × human CD18 chimeric constructs were generated and coexpressed with bovine CD11a in K562 cells. Studies with the chimeric leukocyte function-associated antigen 1 transductants demonstrate that the site required for LktA binding and biological effects resides within amino acid residues 500 and 600 of the extracellular region of bovine CD18.
Role for Mannose Binding Lectin in the Prevention of Mycoplasma Infection
Authors: Hamvas Renata M. J. , Johnson Marina , Vlieger Arine M. , Ling Clare , Sherriff Andrea , Wade Angela , Klein Nigel J. , Turner Malcolm W. , Webster A. David B.
Published: July 2005

Polymorphisms in exon 1 of theMBL-2gene, resulting in reduced plasma levels of mannose binding lectin, were significantly overrepresented in 23 patients with primary antibody deficiency and culture-proven mycoplasma infections (P= 0.0038). This association persisted with the inclusion of a further nine suspected (doxycycline-responsive) cases (P= 0.0087). The lectin was shown to bind to three strains of mycoplasma.
Staphylococcus aureus
Infection of Epidermal Keratinocytes Promotes Expression of Innate Antimicrobial Peptides
Authors: Menzies Barbara E. , Kenoyer Aimee
Published: July 2005

Keratinocytes upregulate expression of endogenous antimicrobial peptides in response to inflammatory stimuli. We show that both viable and heat-inactivated
Staphylococcus aureus
and lipoteichoic acid differentially alter expression of these peptides upon contact with human keratinocytes. The findings indicate a diversity of staphylococcal factors involved in upregulation of antimicrobial peptide expression in cutaneous epithelia.
Recombinant Proteins ofCryptosporidium parvumInduce Proliferation of Mesenteric Lymph Node Cells in Infected Mice
Authors: Singh Inderpal , Theodos Cynthia , Tzipori Saul
Published: July 2005

Recombinant antigens ofCryptosporidium parvum, Cp900 and Cp40 but not Cp15, stimulatedC. parvum-specific proliferative immune responses of mesenteric lymph node cells in C57BL/6J mice infected with different isolates (MD, GCH1, UCP, and IOWA) ofC. parvum, indicating that both Cp900 and Cp40 are immunodominant targets of cellular immune responses duringC. parvuminfection.
Prolonged Survival of a Murine Model of Cerebral Malaria by Kynurenine Pathway Inhibition
Authors: Clark Catherine J. , Mackay Gillian M. , Smythe George A. , Bustamante Sonia , Stone Trevor W. , Phillips R. Stephen
Published: July 2005

C57BL/6J mice infected withPlasmodium bergheiANKA develop neurological dysfunction and die within 7 days of infection. We show that treatment of infected mice with a kynurenine-3-hydroxylase inhibitor prevents them from developing neurological symptoms and extends their life span threefold until severe anemia develops.
Infectivity of
Cryptosporidium hominis
and
Cryptosporidium parvum
Genotype 2 Isolates in Immunosuppressed Mongolian Gerbils
Authors: Baishanbo Asiya , Gargala Gilles , Delaunay Agnès , François Arnaud , Ballet Jean-Jacques , Favennec Loïc
Published: July 2005

One-month-old dexamethasone-immunosuppressed Mongolian gerbils were challenged with 1 oocyst to 2 × 10
5
oocysts from two isolates genotyped as
Cryptosporidium hominis
and
C. parvum
(genotype 2), respectively. A similar dose-dependent gut infection was obtained, and the initial genotype maintained for 21 to 22 days. The data suggest that immunosuppressed gerbils provide a reliable rodent model of persistent
C. hominis
infection.
Protection against Aerosolized
Yersinia pestis
Challenge following Homologous and Heterologous Prime-Boost with Recombinant Plague Antigens
Authors: Glynn Audrey , Roy Chad J. , Powell Bradford S. , Adamovicz Jeffrey J. , Freytag Lucy C. , Clements John D.
Published: July 2005

A
Yersinia pestis
-derived fusion protein (F1-V) has shown great promise as a protective antigen against aerosol challenge with
Y. pestis
in murine studies. In the current study, we examined different prime-boost regimens with F1-V and demonstrate that (i) boosting by a route other than the route used for the priming dose (heterologous boosting) protects mice as well as homologous boosting against aerosol challenge with
Y. pestis
, (ii) parenteral immunization is not required to protect mice against aerosolized plague challenge, (iii) the route of immunization and choice of adjuvant influence the magnitude of the antibody response as well as the immunoglobulin G1 (IgG1)/IgG2a ratio, and (iv) inclusion of an appropriate adjuvant is critical for nonparenteral immunization.
Similarity of Gene Expression Patterns in Human Alveolar Macrophages in Response to
Pseudomonas aeruginosa
and
Burkholderia cepacia
Authors: Worgall Stefan , Heguy Adriana , Luettich Karsta , O'Connor Timothy P. , Harvey Ben-Gary , Quadri Luis E. N. , Crystal Ronald G.
Published: July 2005

To determine if differences in the severity of pulmonary infection in cystic fibrosis seen with late isolates of
Pseudomonas aeruginosa
and
Burkholderia cepacia
are associated with differences in the initial response of alveolar macrophages (AM) to these pathogens, we assessed gene expression changes in human AM in response to infection with a laboratory strain, early and late clinical isolates of
P. aeruginosa
, and
B. cepacia
. Analysis of gene expression changes at the RNA level using oligonucleotide microarrays, following exposure to laboratory
P. aeruginosa
strain PAK, showed significant (
P
< 0.01) >2.5-fold upregulation of 42 genes and >2.5-fold downregulation of 45 genes. The majority of the changes in gene expression involved genes as part of inflammatory pathways and signaling systems. Interestingly, similar responses were observed following exposure of AM to early and late clinical isolates of
P. aeruginosa
, as well as with
B. cepacia
, suggesting that the more severe clinical outcome of infections with late clinical isolates of
P. aeruginosa
or with
B. cepacia
cannot be explained by differences in the early interactions of these organisms with the human AM, as reflected by the similarity of gene expression changes in response to exposure of AM to these pathogens.
Mutation of the Zinc-Binding Metalloprotease Motif AffectsBacteroides fragilisToxin Activity but Does Not Affect Propeptide Processing
Authors: Franco Augusto A. , Buckwold Simy L. , Shin Jai W. , Ascon Miguel , Sears Cynthia L.
Published: July 2005

To evaluate the role of the zinc-binding metalloprotease inBacteroides fragilistoxin (BFT) processing and activity, the zinc-binding consensus sequences (H348, E349, H352, G355, H358, and M366) were mutated by site-directed-mutagenesis. Our results indicated that single point mutations in the zinc-binding metalloprotease motif do not affect BFT processing but do reduce or eliminate BFT biologic activity in vitro.
Campylobacter jejuni
Gene Expression in the Chick Cecum: Evidence for Adaptation to a Low-Oxygen Environment
Authors: Woodall C. A. , Jones M. A. , Barrow P. A. , Hinds J. , Marsden G. L. , Kelly D. J. , Dorrell N. , Wren B. W. , Maskell D. J.
Published: July 2005

Transcriptional profiling of
Campylobacter jejuni
during colonization of the chick cecum identified 59 genes that were differentially expressed in vivo compared with the genes in vitro. The data suggest that
C. jejuni
regulates electron transport and central metabolic pathways to alter its physiological state during establishment in the chick cecum.
Heterologous Prime-Boost Vaccination with the LACK Antigen Protects against Murine Visceral Leishmaniasis
Authors: Dondji Blaise , Pérez-Jimenez Eva , Goldsmith-Pestana Karen , Esteban Mariano , McMahon-Pratt Diane
Published: July 2005

This study reports the efficacy of a heterologous prime-boost vaccination using DNA and vaccinia viruses (Western Reserve [WR] virus and modified [attenuated] vaccinia virus Ankara [MVA]) expressing the LACK antigen (Leishmaniahomologue of receptors for activated C kinase) and an intradermal murine infection model employingLeishmania infantum. At 1 month postinfection, vaccinated mice showed high levels of protection in the draining lymph node (240-fold reduction in parasite burden) coupled with significant levels of gamma interferon (20 to 200 ng/ml) and tumor necrosis factor alpha/lymphotoxin (8 to 134 pg/ml). Significant but lower levels of protection (6- to 30-fold) were observed in the spleen and liver. Comparable levels of protection were found for mice boosted with either LACK-WR or LACK-MVA, supporting the use of an attenuated vaccinia virus-based vaccine against human visceral leishmaniasis.
MODELING THE RAILWAY TRAFFIC USING CELLULAR AUTOMATA MODEL
Authors: LI KE-PING , GAO ZI-YOU , NING BIN
Published: July 2005

The NaSch model is a probabilistic cellular automaton (CA) model for the description of single-lane highway traffic. Based on this model, we propose a new cellular automata model for the railway traffic. The signaling system adopted in this work is the moving block signaling system. In our model, the distance between the following train and its leading train takes into account the velocity of the leading train. The simulation results demonstrate that our model is suitable for simulating the railway traffic. Compared our scheme to the traditional moving-space-block scheme, it is obvious that using our scheme, not only the line capacity can be increased, but also the traffic flow states are safer.
COMMENTS ON REGULARIZATION AMBIGUITIES AND LOCAL GAUGE SYMMETRIES
Authors: CASANA R. , PIMENTEL B. M.
Published: July 2005

We study the regularization ambiguities in an exact renormalized (1 +1)-dimensional field theory. We show a relation between the regularization ambiguities and the coupling parameters of the theory as well as their role in the implementation of a local gauge symmetry at quantum level.
PREDICTING PEPTIDE INTERACTIONS WITH MODEL CLASS II MHC STRUCTURES
Authors: SWAIN MARTIN T. , BROOKS ANTHONY J. , KEMP GRAHAM J. L.
Published: July 2005

An automated method for constructing 3D models of class II MHC structures that uses constraint logic programming to select side-chain conformations is described. This method follows a comparative modeling approach in basing the model structures on experimentally determined MHC-peptide structures, but it uses constraints to ease open the peptide binding groove so that the modeled MHC structure is a less specific fit for the co-crystallized peptide in the starting structure. The resulting models are used by a "peptide threading" program that attempts to predict peptides from a protein sequence that will bind strongly to particular MHC alleles. Our results indicate that MHC models that have been constructed in this way enable the peptide threading program to make binding predictions that are comparable with those obtained when using experimentally determined MHC structures, suggesting that a combined modeling and peptide threading approach is worth pursuing for MHC molecules for which experimentally determined structures are not available.
THE PREVALENCE OF CRANIOMANDIBULAR DISORDERS (CMD) IN MALE COMPETITIVE ROWERS
Authors: Dietrich Stefan , Bull Anthony M.J. , Leher Anna , McGregor Alison H. , Lechner Karl–Heinz , Toumazou Chris , Ahlers M. Oliver
Published: July 2005

Objective: Based on observations that competitive rowers show a high facial activity during exercise, the aim of this study was to assess the prevalence of the signs and symptoms of Craniomandibular Disorders (CMD) in male rowers by evaluating functional and muscular parameters.

Methods: In a cross-sectional study, 16 male rowers were compared with 16 controls. All subjects filled out a general questionnaire and underwent dental functional analysis.

Results: The rowing volunteers reported pain/complaints in the head/neck/facial area more often than the controls and showed more parafunctional activities. Oral inspection showed a significantly higher prevalence of tongue and buccal impressions, abrasion and enamel cracks. Muscular palpation pain was significant in the rower group for the M. masseter profundus et superficialis, the temporomandibular joint (TMJ) area, and the M. pterygoideus lateralis.

Conclusion: The study indicates a high prevalence for the signs and symptoms of CMD in male competitive rowers, which may be attributed to the rowing activity and/or the associated training program.
QUASI SYMPLECTIC INTEGRATORS: AN ALTERNATIVE TO NOSÉ HOOVER DYNAMICS?
Authors: MANNELLA RICCARDO
Published: July 2005

Quasi symplectic algorithms for the numerical integration of Langevin equations describing systems in a canonical ensemble are discussed. It is shown that they could be an alternative to molecular dynamics simulations done with a Nosé Hoover booster.
ADAPTIVE GOVERNANCE OF SOCIAL-ECOLOGICAL SYSTEMS
Authors: Folke Carl , Hahn Thomas , Olsson Per , Norberg Jon
Published: July 2005

▪ Abstract  We explore the social dimension that enables adaptive ecosystem-based management. The review concentrates on experiences of adaptive governance of social-ecological systems during periods of abrupt change (crisis) and investigates social sources of renewal and reorganization. Such governance connects individuals, organizations, agencies, and institutions at multiple organizational levels. Key persons provide leadership, trust, vision, meaning, and they help transform management organizations toward a learning environment. Adaptive governance systems often self-organize as social networks with teams and actor groups that draw on various knowledge systems and experiences for the development of a common understanding and policies. The emergence of “bridging organizations” seem to lower the costs of collaboration and conflict resolution, and enabling legislation and governmental policies can support self-organization while framing creativity for adaptive comanagement efforts. A resilient social-ecological system may make use of crisis as an opportunity to transform into a more desired state.
Differential cardioprotective/cardiotoxic effects mediated by β-adrenergic receptor subtypes
Authors: Bernstein Daniel , Fajardo Giovanni , Zhao Mingming , Urashima Takashi , Powers Jennifer , Berry Gerald , Kobilka Brian K.
Published: July 2005

Recent data suggest that β-adrenergic receptor subtypes couple differentially to signaling pathways regulating cardiac function vs. cardiac remodeling. To dissect the roles of β1- vs. β2-receptors in the pathogenesis of cardiomyopathy, doxorubicin was administered to β1, β2, and β1/β2 knockout (−/−) and wild-type mice. Expression and activation of MAPKs were measured. Wild-type and β1−/− mice showed no acute cardiovascular effects, whereas β2−/− mice all died within 30 min. The additional deletion of the β1-receptor (β1/β2−/−) totally rescued this toxicity. β2−/− mice developed decreased contractile function, hypotension, QTc prolongation, and ST segment changes and a 20-fold increase in p38 MAPK activity not seen in the other genotypes. The MAPK inhibitor SB-203580 rescued β2−/− mice from this acute toxicity. The enhanced toxicity in β2−/− mice was also recapitulated in wild-type mice with the β2-selective antagonist ICI-118,551, although the rescue effect of the β1-deletion was not recapitulated using the β1-selective antagonist metoprolol or the nonselective β-antagonist propranolol. These data suggest that β2-adrenergic receptors play a cardioprotective role in the pathogenesis of cardiomyopathy, whereas β1-adrenergic receptors mediate at least some of the acute cardiotoxicity of anthracyclines. Differential activation of MAPK isoforms, previously shown in vitro to regulate β-agonist as well as doxorubicin cardiotoxicity, appears to play a role in mediating the differential effects of these β-adrenergic receptor subtypes in vivo.
Upregulation of adrenomedullin and its receptor components during cardiomyocyte hypertrophy induced by chronic inhibition of nitric oxide synthesis in rats
Authors: Bell David , Zhao You-You , Kelso Elizabeth J. , McHenry Eugene M. , Rush Louise M. , Lamont Victoria M. , Nicholls D. Paul , McDermott Barbara J.
Published: July 2005

Adrenomedullin may provide a compensatory mechanism to attenuate left ventricular hypertrophy (LVH). Nitric oxide synthase inhibition, induced by chronic administration of Nω-nitro-l-arginine methyl ester (l-NAME) to rats, induces cardiac hypertrophy in some, but not all cases; there are few reports of direct assessment of cardiomyocyte parameters. The objective was to characterize hypertrophic parameters in left (LV) and right ventricular (RV) cardiomyocytes after administration of l-NAME to rats for 8 wk and to determine whether adrenomedullin and its receptor components were upregulated. After treatment with l-NAME (20 and 50 mg·kg−1·day−1), compared with nontreated animals, 1) systolic blood pressure increased (by 34.2 and 104.9 mmHg), 2) heart weight-to-body wt ratio increased 24.1% at the higher dose ( P < 0.05), 3) cardiomyocyte protein mass increased ( P = NS), 4) cardiomyocyte protein synthesis ([14C]phenylalanine incorporation) increased ( P < 0.05), 5) expression of skeletal α-actin, atrial natriuretic peptide, brain natriuretic peptide, and ET-1 mRNAs was enhanced ( P < 0.05) in LV but not RV cardiomyocytes at 20 and 50 mg·kg−1·day−1, respectively, and 6) expression of adrenomedullin, receptor activity-modifying protein 3 (RAMP3), and RAMP2 (but not calcitonin receptor-like receptor and RAMP1) mRNAs was increased by l-NAME (20 mg·kg−1·day−1) in LV. In conclusion, l-NAME enhanced protein synthesis in both LV and RV cardiomyocytes but elicited a hypertrophic phenotype accompanied by altered expression of the counterregulatory peptide adrenomedullin and receptor components (RAMP2, RAMP3) in LV only, indicating that the former is due to impaired nitric oxide synthesis, whereas the phenotypic changes are due to pressure overload.
Microvascular blood viscosity in vivo and the endothelial surface layer
Authors: Pries A. R. , Secomb T. W.
Published: July 2005

The apparent viscosity of blood in glass tubes declines with decreasing diameter (Fåhraeus-Lindqvist effect) and exhibits a distinctive minimum at 6–7 μm. However, flow resistance in vivo in small vessels is substantially higher than predicted by in vitro viscosity data. The presence of a thick endothelial surface layer (ESL) has been proposed as the primary cause for this discrepancy. Here, a physical model is proposed for microvascular flow resistance as a function of vessel diameter and hematocrit in vivo; it combines in vitro blood viscosity with effects of a diameter-dependent ESL. The model was developed on the basis of flow distributions observed in three microvascular networks in the rat mesentery with 392, 546, and 383 vessel segments, for which vessel diameters, network architecture, flow velocity, and hematocrit were determined by intravital microscopy. A previously described hemodynamic simulation was used to predict the distributions of flow and hematocrit from the assumed model for effective blood viscosity. The dependence of ESL thickness on vessel diameter was estimated by minimizing deviations of predicted values for velocities, flow directions, and hematocrits from measured data. Optimal results were obtained with a layer thickness of ∼0.8–1 μm for 10- to 40-μm-diameter vessels and declined strongly for smaller diameters, with an additional hematocrit-dependent impact on flow resistance exhibiting a maximum for ∼10-μm-diameter vessels. These results show that flow resistance in vivo can be explained by in vitro blood viscosity and the presence of an ESL and indicate the rheologically effective thickness of the ESL in microvessels.
Hybrid duplex: a novel method to study the contractile function of heterogeneous myocardium
Authors: Protsenko Yuri L. , Routkevitch Sergey M. , Gur'ev Vyacheslav Y. , Katsnelson Leonid B. , Solovyova Olga , Lookin Oleg N. , Balakin Alexander A. , Kohl Peter , Markhasin Vladimir S.
Published: July 2005

In an earlier study, we experimentally mimicked the effects of mechanical interaction between different regions of the ventricular wall by allowing pairs of independently maintained cardiac muscle fibers to interact mechanically in series or in parallel. This simple physiological model of heterogeneous myocardium, which has been termed “duplex,” has provided new insight into basic effects of cardiac electromechanical heterogeneity. Here, we present a novel “hybrid duplex,” where one of the elements is an isolated cardiac muscle and the other a “virtual cardiac muscle.” The virtual muscle is represented by a computational model of cardiomyocyte electromechanical activity. We present in detail the computer-based digital control system that governs the mechanical interaction between virtual and biological muscle, the software used for data analysis, and working implementations of the model. Advantages of the hybrid duplex method are discussed, and experimental recordings are presented for illustration and as proof of the principle.
Cardioprotection induced by cardiac-specific overexpression of fibroblast growth factor-2 is mediated by the MAPK cascade
Authors: House Stacey L. , Branch Kevin , Newman Gilbert , Doetschman Thomas , Schultz Jo El J.
Published: July 2005

Our laboratory showed previously that cardiac-specific overexpression of FGF-2 [FGF-2 transgenic (Tg)] results in increased recovery of contractile function and decreased infarct size after ischemia-reperfusion injury. MAPK signaling is downstream of FGF-2 and has been implicated in other models of cardioprotection. Treatment of FGF-2 Tg and wild-type hearts with U-0126, a MEK-ERK pathway inhibitor, significantly reduced recovery of contractile function after global low-flow ischemia-reperfusion injury in FGF-2 Tg (86 ± 2% vehicle vs. 66 ± 4% U-0126; P < 0.05) but not wild-type (61 ± 7% vehicle vs. 67 ± 7% U-0126) hearts. Similarly, MEK-ERK inhibition significantly increased myocardial infarct size in FGF-2 Tg (12 ± 3% vehicle vs. 31 ± 2% U-0126; P < 0.05) but not wild-type (30 ± 4% vehicle vs. 36 ± 7% U-0126) hearts. In contrast, treatment of FGF-2 Tg and wild-type hearts with SB-203580, a p38 inhibitor, did not abrogate FGF-2-induced cardioprotection from postischemic contractile dysfunction. Instead, inhibition of p38 resulted in decreased infarct size in wild-type hearts (30 ± 4% vehicle vs. 11 ± 2% SB-203580; P < 0.05) but did not alter infarct size in FGF-2 Tg hearts (12 ± 3% vehicle vs. 14 ± 1% SB-203580). Western blot analysis of ERK and p38 activation revealed signaling alterations in FGF-2 Tg and wild-type hearts during early ischemia or reperfusion injury. In addition, MEK-independent ERK inhibition by p38 was observed during early ischemic injury. Together these data suggest that activation of ERK and inhibition of p38 by FGF-2 is cardioprotective during ischemia-reperfusion injury.
Nitric oxide modulates oxygen consumption by arteriolar walls in rat skeletal muscle
Authors: Shibata Masahiro , Ichioka Shigeru , Kamiya Akira
Published: July 2005

To study the role of nitric oxide (NO) in regulating oxygen consumption by vessel walls, the oxygen consumption rate of arteriolar walls in rat cremaster muscle was measured in vivo during flow-induced vasodilation and after inhibiting NO synthesis. The oxygen consumption rate of arteriolar walls was calculated based on the intra- and perivascular Po2values measured by phosphorescence quenching laser microscopy. The perivascular Po2value of the arterioles during vasodilation was significantly higher than under control conditions, although the intravascular Po2values under both conditions were approximately the same. Inhibition of NO synthesis, on the other hand, caused a significant increase in arterial blood pressure and a significant decrease in arteriolar diameter. Inhibition of NO synthesis also caused a significant decrease in both the intra- and perivascular Po2values of the arterioles. Inhibition of NO synthesis increased the oxygen consumption rate of the vessel walls by 42%, whereas enhancement of flow-induced NO release decreased it by 34%. These results suggest that NO plays an important role not only as a regulator of peripheral vascular tone but also as a modulator of tissue oxygenation by reducing oxygen consumption by vessel walls. In addition, enhancement of NO release during exercise may facilitate efficient oxygen supply to the surrounding high metabolic tissue.
Hyaluronidase treatment of coronary glycocalyx increases reactive hyperemia but not adenosine hyperemia in dog hearts
Authors: VanTeeffelen Jurgen W. G. E. , Dekker Simone , Fokkema Dirk S. , Siebes Maria , Vink Hans , Spaan Jos A. E.
Published: July 2005

Because adenosine is commonly used for inducing maximal coronary hyperemia in the clinic, it is imperative that adenosine-induced hyperemia (AH) resembles coronary hyperemia that can be attained by endogenous stimuli. In the present study we hypothesized that coronary reactive hyperemia (RH) is limited compared with AH due to the presence of the glycocalyx and that the AH response is therefore unable to detect glycocalyx modifications. In anesthetized open-chest dogs, blood flow and pressure were measured in the left circumflex artery. RH after 15-s occlusion was compared with an intracoronary infusion of adenosine (650 μg; AH) during control conditions and after intracoronary treatment of the glycocalyx with hyaluronidase (20.000 U, 2 × 20 min; n = 6) or heat-inactivated hyaluronidase ( n = 5). During control, coronary conductance during RH was 1.49 ± 0.15 ml·mmHg−1·min−1 and 76 ± 7% of coronary conductance during AH ( P < 0.05). After hyaluronidase, RH conductance increased ( P < 0.01) by 43 ± 13% and became 93 ± 4% of AH conductance ( P = NS). Heat-inactivated hyaluronidase had no effect on RH and AH conductance. Our results demonstrate that adenosine-induced coronary hyperemia profoundly exceeds RH and that the difference is virtually abolished on selective removal of the glycocalyx. It is concluded that, compared with RH, adenosine-induced coronary hyperemia is not affected by modification of the glycocalyx. This glycocalyx insensitivity should be taken into account when using adenosine-induced coronary hyperemia as a marker for vasodilating capacity to an ischemic stimulus.
Effect of vitamin C and l-NMMA on the inotropic response to dobutamine in patients with heart failure
Authors: Mak Susanna , Overgaard Christopher B. , Newton Gary E.
Published: July 2005

The positive effect of vitamin C on left ventricular (LV) inotropic responses to dobutamine, observed in patients with preserved LV function, is lost in heart failure (HF). We tested the hypothesis that in HF, endogenous nitric oxide (NO) opposes the positive effect of vitamin C on adrenergically stimulated contractility by examining the effects of vitamin C on dobutamine responses during NO synthase inhibition. In 11 HF patients, a micromanometer-tipped catheter was inserted into the LV and an infusion catheter was positioned in the left main coronary artery. The peak positive rate of change of LV pressure (LV +dP/d t) was measured in response to intravenous dobutamine (Dob-1). After recontrol, intracoronary NG-monomethyl-l-arginine (l-NMMA) was infused before reinfusion of dobutamine (l-NMMA + Dob-2). Finally, intracoronary vitamin C was infused in addition to intracoronary l-NMMA and dobutamine (l-NMMA + Dob-2 + vitamin C). Intracoronary l-NMMA alone had no effect on LV +dP/d t. After a stable inotropic response to intracoronary l-NMMA and dobutamine was established, the addition of intracoronary vitamin C resulted in a modest but significant increase in LV +dP/d t. The change in LV +dP/d t in response to dobutamine alone was 25 ± 5%, with intracoronary l-NMMA, 27 ± 6%, and with intracoronary l-NMMA plus vitamin C, 37 ± 5% ( P < 0.05 vs. Dob-1 and l-NMMA + Dob-2). These findings demonstrate that an interaction between endogenous NO and redox environment exists and exerts some influence on stimulated contractility in HF.