bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a Meningococcall-Glutamate ABC Transporter Operon Essential for Growth in Low-Sodium Environments
Authors: Monaco Caterina , Talà Adelfia , Spinosa Maria Rita , Progida Cinzia , De Nitto Eleanna , Gaballo Antonio , Bruni Carmelo B. , Bucci Cecilia , Alifano Pietro 
Published: February 2006

ABSTRACTGdhR is a meningococcal transcriptional regulator that was previously shown to positively control the expression ofgdhA, encoding the NADP-specificl-glutamate dehydrogenase (NADP-GDH), in response to the growth phase and/or to the carbon source. In this study we used reverse transcriptase-PCR-differential display (to identify additional GdhR-regulated genes. The results indicated that GdhR, in addition to NADP-GDH, controls the expression of a number of genes involved in glucose catabolism by the Entner-Doudoroff pathway and inl-glutamate import by an unknown ABC transport system. The genes encoding the putative periplasmic substrate-binding protein (NMB1963) and the permease (NMB1965) of the ABC transporter were genetically inactivated. Uptake experiments demonstrated an impairment ofl-glutamate import in the NMB1965-defective mutant in the absence or in the presence of a low sodium ion concentration. In contrast, at a sodium ion concentration above 60 mM, the uptake defect disappeared, possibly because the activity of a sodium-driven secondary transporter became predominant. Indeed, the NMB1965-defective mutant was unable to grow at a low sodium ion concentration (<20 mM) in a chemically defined medium containingl-glutamate and four other amino acids that supported meningococcal growth, but it grew when the sodium ion concentration was raised to higher values (>60 mM). The same growth phenotype was observed in the NMB1963-defective mutant. Cell invasion and intracellular persistence assays and expression data during cell invasion provided evidence that thel-glutamate ABC transporter, tentatively named GltT, was critical for meningococcal adaptation in the low-sodium intracellular environment.
Immunoprotection of Recombinant Leptospiral Immunoglobulin-Like Protein A against
Leptospira interrogans
Serovar Pomona Infection
Authors: Palaniappan Raghavan U. M. , McDonough Sean P. , Divers Thomas J. , Chen Chia-Sui , Pan Ming-Jeng , Matsumoto Mitsuharu , Chang Yung-Fu 
Published: February 2006

ABSTRACT

We previously reported the cloning and characterization of leptospiral immunoglobulin-like proteins LigA and LigB of
Leptospira interrogans
. LigA and LigB are conserved at the amino-terminal region but are variable at the carboxyl-terminal region. Here, we evaluate the potential of recombinant LigA (rLigA) as a vaccine candidate against infection by
L. interrogans
serovar Pomona in a hamster model. rLigA was truncated into conserved (rLigAcon) and variable (rLigAvar) regions and expressed in
Escherichia coli
as a fusion protein with glutathione-
S
-transferase (rLigA). Golden Syrian hamsters were immunized at 3 and 6 weeks of age with rLigA (rLigAcon and rLigAvar) with aluminum hydroxide as an adjuvant. Hamsters given recombinant glutathione-
S
-transferase (rGST)-adjuvant and phosphate-buffered saline-adjuvant served as nonvaccinated controls. Three weeks after the last vaccination, all animals were challenged intraperitoneally with 10
8
L. interrogans
serovar Pomona bacteria (NVSL 1427-35-093002). All hamsters immunized with recombinant LigA survived after challenge and had no significant histopathological changes. In contrast, nonimmunized and rGST-immunized hamsters were subjected to lethal doses, and the hamsters that survived showed severe tubulointerstitial nephritis. All vaccinated animals showed a rise in antibody titers against rLigA. Results from this study indicate that rLigA is a potential vaccine candidate against
L. interrogans
serovar Pomona infection.
Cytosolic Phospholipase A
2
Enzymes Are Not Required by Mouse Bone Marrow-Derived Macrophages for the Control of
Mycobacterium tuberculosis
In Vitro
Authors: Vandal Omar H. , Gelb Michael H. , Ehrt Sabine , Nathan Carl F. 
Published: February 2006

ABSTRACT

During the course of infection
Mycobacterium tuberculosis
predominantly resides within macrophages, where it encounters and is often able to resist the antibacterial mechanisms of the host. In this study, we assessed the role of macrophage phospholipases A
2
(PLA
2
s) in defense against
M. tuberculosis
. Mouse bone marrow-derived macrophages (BMDMs) expressed cPLA
2
-IVA, cPLA
2
-IVB, iPLA
2
-VI, sPLA
2
-IIE, and sPLA
2
-XIIA. The expression of cPLA
2
-IVA was increased in response to
M. tuberculosis
, gamma interferon, or their combination, and cPLA
2
-IVA mediated the release of arachidonic acid, which was stimulated by
M. tuberculosis
in activated, but not unactivated, macrophages. We confirmed that arachidonic acid is highly mycobactericidal in a concentration- and pH-dependent manner in vitro. However, when
M. tuberculosis
-infected macrophages were treated with PLA
2
inhibitors, intracellular survival of
M. tuberculosis
was not affected, even in inducible nitric oxide synthase-deficient macrophages, in which a major bactericidal mechanism is removed. Moreover, intracellular survival of
M. tuberculosis
was similar in cPLA
2
-IVA-deficient and wild-type macrophages. Our results demonstrate that the cytosolic PLA
2
s are not required by murine BMDMs to kill
M. tuberculosis
.
A Mycobacterial Operon Essential for Virulence In Vivo and Invasion and Intracellular Persistence in Macrophages
Authors: Gao Lian-Yong , Pak Melissa , Kish Rabab , Kajihara Kimberly , Brown Eric J. 
Published: February 2006

ABSTRACT

The ability to invade and grow in macrophages is necessary for
Mycobacterium tuberculosis
to cause disease. We have found a
Mycobacterium marinum
locus of two genes that is required for both invasion and intracellular survival in macrophages. The genes were designated
iipA
(mycobacterial invasion and intracellular persistence) and
iipB
. The
iip
mutant, which was created by insertion of a kanamycin resistance gene cassette at the 5′ region of
iipA
, was completely avirulent to zebra fish. Expression of the
M. tuberculosis
orthologue of
iipA
, Rv1477, fully complemented the
iip
mutant for infectivity in vivo, as well as for invasion and intracellular persistence in macrophages. In contrast, the
iipB
orthologue, Rv1478, only partially complemented the
iip
mutant in vivo and restored invasion but not intracellular growth in macrophages. While IipA and IipB differ at their N termini, they are highly similar throughout their C-terminal NLPC_p60 domains. The p60 domain of Rv1478 is fully functional to replace that of Rv1477, suggesting that the N-terminal sequence of Rv1477 is required for full virulence in vivo and in macrophages. Further mutations demonstrated that both Arg-Gly-Asp (RGD) and Asp-Cys-Ser-Gly (DCSG) sequences in the p60 domain are required for function. The
iip
mutant exhibited increased susceptibility to antibiotics and lysozyme and failed to fully separate daughter cells in liquid culture, suggesting a role for
iip
genes in cell wall structure and function. Altogether, these studies demonstrate an essential role for a p60-containing protein, IipA, in the pathogenesis of
M. marinum
infection.
γδ T Cells Regulate the Early Inflammatory Response toBordetella pertussisInfection in the Murine Respiratory Tract
Authors: Zachariadis O. , Cassidy J. P. , Brady J. , Mahon B. P. 
Published: February 2006

ABSTRACTThe role of γδ T cells in the regulation of pulmonary inflammation followingBordetella pertussisinfection was investigated. Using a well-characterized murine aerosol challenge model, inflammatory events in mice with targeted disruption of the T-cell receptor δ-chain gene (γδ TCR−/−mice) were compared with those in wild-type animals. Early following challenge withB. pertussis, γδ TCR−/−mice exhibited greater pulmonary inflammation, as measured by intra-alveolar albumin leakage and lesion histomorphometry, yet had lower contemporaneous bacterial lung loads. The larger numbers of neutrophils and macrophages and the greater concentration of the neutrophil marker myeloperoxidase in bronchoalveolar lavage fluid from γδ TCR−/−mice at this time suggested that differences in lung injury were mediated through increased leukocyte trafficking into infected alveoli. Furthermore, flow cytometric analysis found the pattern of recruitment of natural killer (NK) and NK receptor+T cells into airspaces differed between the two mouse types over the same time period. Taken together, these findings suggest a regulatory influence for γδ T cells over the early pulmonary inflammatory response to bacterial infection. The absence of γδ T cells also influenced the subsequent adaptive immune response to specific bacterial components, as evidenced by a shift from a Th1 to a Th2 type response against theB. pertussisvirulence factor filamentous hemagglutinin in γδ TCR−/−mice. The findings are relevant to the study of conditions such as neonatalB. pertussisinfection and acute respiratory distress syndrome where γδ T cell dysfunction has been implicated in the inflammatory process.
Toll-Like Receptor 2 Mediates Alveolar Macrophage Response toPneumocystis murina
Authors: Zhang Chen , Wang Shao-Hung , Lasbury Mark E. , Tschang Dennis , Liao Chung-Ping , Durant Pamela J. , Lee Chao-Hung 
Published: February 2006

ABSTRACTThe innate immune response toPneumocystisinfection is not well understood. In this study, normal C57BL/6 mouse alveolar macrophages were found to respond toPneumocystis murinaorganisms through Toll-like receptor 2 (TLR2), leading to the nuclear translocation of NF-κB and the production of proinflammatory cytokine tumor necrosis factor alpha (TNF-α) and chemokine macrophage inflammatory protein 2 (MIP-2).P. murinastimulation of normal alveolar macrophages from C57BL/6 mice resulted in increased TLR2 transcription but not increased TLR4 transcription. In gain-of-function studies with HEK293 cells expressing TLR2 or TLR4, only TLR2 was found to stimulate an NF-κB response toP. murina. TNF-α and MIP-2 production in response toP. murinaby mouse alveolar macrophages was inhibited by a monoclonal antibody that specifically blocked the ligand-binding ability of TLR2. Alveolar macrophages from TLR2 knockout (TLR2−/−) mice showed little increase in TNF-α and MIP-2 mRNA levels uponP. murinastimulation. An in vivo study showed that TLR2−/−mice challenged withP. murinahad reduced cytokine responses. These results indicate that TLR2 plays a major role in the innate immune response toP. murina.
Protein Expression Profiling of
Coccidioides posadasii
by Two-Dimensional Differential In-Gel Electrophoresis and Evaluation of a Newly Recognized Peroxisomal Matrix Protein as a Recombinant Vaccine Candidate
Authors: Orsborn Kris I. , Shubitz Lisa F. , Peng Tao , Kellner Ellen M. , Orbach Marc J. , Haynes Paul A. , Galgiani John N. 
Published: February 2006

ABSTRACT

Coccidioides posadasii
and
Coccidioides immitis
are dimorphic, soil-dwelling pathogenic ascomycetes endemic to the southwestern United States. Infection can result from inhalation of a very few arthroconidia, but following natural infection, long-lived immunity is the norm. Previous work in the field has shown that spherule-derived vaccines afford more protection than those from mycelia. We have used two-dimensional differential in-gel electrophoresis coupled with nano-high-performance liquid chromatography-tandem mass spectrometry to directly assess both absolute abundance and differential expression of proteins in the spherule and the mycelial phases of
C. posadasii
with the intent to identify potential vaccine candidates. Peptides derived from 40 protein spots were analyzed and a probable identity was assigned to each. One spherule-abundant protein, identified as Pmp1, showed homology to allergens from
Aspergillus fumigatus
and other fungi, all of which exhibit similarity to yeast thiol peroxidases. Recombinant Pmp1 was reactive with serum from individuals with both acute and protracted disease, and evoked protection in two murine models of infection with
C. posadasii
. These results demonstrate the utility of proteomic analysis as a point of discovery for protective antigens for possible inclusion in a vaccine candidate to prevent coccidioidomycosis.
Genome-Wide Expression Analysis of Lipopolysaccharide-Induced Mastitis in a Mouse Model
Authors: Zheng Jiamao , Watson Anjanette D. , Kerr David E. 
Published: February 2006

ABSTRACT

To better understand the acute host response to
Escherichia coli
mastitis, we analyzed gene expression patterns of approximately 23,000 transcripts 4 h after an intramammary infusion of lipopolysaccharide (LPS) in a mouse model. A total of 489 genes were significantly affected, of which 391 were induced and 98 were repressed. Gene ontology analysis demonstrated that most of the induced genes were associated with the innate immune response, apoptosis, and cell proliferation. Substantial induction of the chemokines CXCL1, CXCL2, and S100A8; the acute-phase protein SAA3; and the LPS binding protein CD14 were confirmed by Northern blot analysis. A subsequent time course experiment revealed CXCL1 induction prior to that of CD14 and SAA3. Mammary epithelial cell cultures also showed marked expression of these factors in response to LPS. The expression of immune-related genes in mammary epithelial cells indicates the importance of this cell type in initiating the inflammatory responses. Repressed genes include several carbohydrate and fatty acid metabolic enzymes and potassium transporters, which may contribute to milk composition changes during mastitis. Therefore, the overall transcription profile, in conjunction with gene ontology analysis, provides a detailed picture of the molecular mechanisms underlying the complex biological processes that occur during LPS-induced mastitis.
Amelioration of Influenza-Induced Pathology in Mice by Coinfection withTrichinella spiralis
Authors: Furze Rebecca C. , Hussell Tracy , Selkirk Murray E. 
Published: February 2006

ABSTRACTIllness due to respiratory virus infection is often induced by excessive infiltration of cells into pulmonary tissues, leading to airway occlusion. We show here that infection withTrichinella spiralisresults in lower levels of tumor necrosis factor in bronchoalveolar lavage fluid and inhibits cellular recruitment into the airways of mice coinfected with influenza A virus. Infiltration of neutrophils and CD4+and CD8+lymphocytes was reduced, resulting in animals gaining weight more rapidly following the initial phase of infection. Influenza resulted in a generalized increase in vascular permeability in pulmonary tissues, and this was suppressed by parasite infection, although the effects were restricted to the early phase of trichinosis. Moreover, the number of cells producing interleukin-10 (IL-10), and the local levels of this cytokine, were reduced, suggesting that amelioration of pulmonary pathology by parasite infection occurs independently of IL-10 production.
A CpG Oligonucleotide Can Protect Mice from a Low Aerosol Challenge Dose ofBurkholderia mallei
Authors: Waag David M. , McCluskie Michael J. , Zhang Ningli , Krieg Arthur M. 
Published: February 2006

ABSTRACTTreatment with an oligodeoxynucleotide (ODN) containing CPG motifs (CpG ODN 7909) was found to protect BALB/c mice from lung infection or death after aerosol challenge withBurkholderia mallei. Protection was associated with enhanced levels of gamma interferon (IFN-γ)-inducible protein 10, interleukin-12 (IL-12), IFN-γ, and IL-6. Preexposure therapy with CpG ODNs may protect victims of a biological attack from glanders.
Routine Markerless Gene Replacement in
Bacillus anthracis
Authors: Janes Brian K. , Stibitz Scott 
Published: February 2006

ABSTRACT

An improved genetic tool suitable for routine markerless allelic exchange in
Bacillus anthracis
has been constructed. Its utility was demonstrated by the introduction of insertions, deletions, and missense mutations on the chromosome and plasmid pXO1 of the Sterne strain of
B. anthracis
.
Monoclonal Antibodies Passively Protect BALB/c Mice against
Burkholderia mallei
Aerosol Challenge
Authors: Treviño Sylvia R. , Permenter Amy R. , England Marilyn J. , Parthasarathy Narayanan , Gibbs Paul H. , Waag David M. , Chanh Tran C. 
Published: February 2006

ABSTRACT

Glanders is a debilitating disease with no vaccine available. Murine monoclonal antibodies were produced against
Burkholderia mallei
, the etiologic agent of glanders, and were shown to be effective in passively protecting mice against a lethal aerosol challenge. The antibodies appeared to target lipopolysaccharide. Humoral antibodies may be important for immune protection against
B. mallei
infection.
Reduced Virulence of an
fliC
Mutant of Shiga-Toxigenic
Escherichia coli
O113:H21
Authors: Rogers Trisha J. , Paton James C. , Wang Hui , Talbot Ursula M. , Paton Adrienne W. 
Published: February 2006

ABSTRACT

The contribution of flagellin to the virulence of the O113:H21 Shiga-toxigenic
Escherichia coli
(STEC) strain 98NK2 was investigated in the streptomycin-treated mouse model. Groups of mice were challenged with either the wild-type STEC or a
fliC
deletion derivative thereof. There was no difference in the level of gut colonization by the two strains, but the
fliC
mutant was significantly less virulent than its parent; the overall survival rates were 43.7% and 81.2%, respectively (
P
< 0.025). This is the first report of a nontoxic accessory virulence factor contributing to a fatal outcome of STEC infection in this model. Although H21 FliC is known to be a potent inducer of CXC chemokines, including interleukin 8, there was no obvious difference in the recruitment of polymorphonuclear leukocytes to the intestinal epithelium of mice challenged with either strain. However, immunofluorescence microscopy suggested that the
fliC
mutant was less capable of forming a close association with the colonic epithelium. This may have reduced the uptake of Stx2 by mice infected with the mutant.
Selective Binding of
Borrelia burgdorferi
OspE Paralogs to Factor H and Serum Proteins from Diverse Animals: Possible Expansion of the Role of OspE in Lyme Disease Pathogenesis
Authors: Hovis Kelley M. , Tran Emily , Sundy Christina M. , Buckles Eric , McDowell John V. , Marconi Richard T. 
Published: February 2006

ABSTRACT

The binding of
Borrelia burgdorferi
OspE, OspF, and family 163 (Elp) proteins to factor H/factor H-like protein 1 (FHL-1) and other serum proteins from different animals was assessed. OspE paralogs bound factor H and unidentified serum proteins from a subset of animals, while OspF and Elp proteins did not. These data advance our understanding of factor H binding, the host range of the Lyme spirochetes, and the expanding role of OspE in pathogenesis.
Commensal Bacteria Influence
Escherichia coli
O157:H7 Persistence and Shiga Toxin Production in the Mouse Intestine
Authors: Gamage Shantini D. , Patton Angela K. , Strasser Jane E. , Chalk Claudia L. , Weiss Alison A. 
Published: February 2006

ABSTRACT

The presence of commensal flora reduced colonization of
Escherichia coli
O157:H7 and production of Shiga toxin (Stx) in the murine intestine. Stx production was not detected in mice colonized with
E. coli
that were resistant to the Shiga toxin phage, but it was detected in mice colonized with phage-susceptible
E. coli
.
Preclinical Evaluation of Two Neutralizing Human Monoclonal Antibodies against Hepatitis C Virus (HCV): a Potential Treatment To Prevent HCV Reinfection in Liver Transplant Patients
Authors: Eren Rachel , Landstein Dorit , Terkieltaub Dov , Nussbaum Ofer , Zauberman Arie , Ben-Porath Judith , Gopher Judith , Buchnick Rachel , Kovjazin Riva , Rosenthal-Galili Ziva , Aviel Sigal , Ilan Ehud , Shoshany Yariv , Neville Lewis , Waisman Tal , Ben-Moshe Ofer , Kischitsky Alberto , Foung Steven K. H. , Keck Zhen-Yong , Pappo Orit , Eid Ahmed , Jurim Oded , Zamir Gidi , Galun Eithan , Dagan Shlomo 
Published: February 2006

ABSTRACT

Passive immunotherapy is potentially effective in preventing reinfection of liver grafts in hepatitis C virus (HCV)-associated liver transplant patients. A combination of monoclonal antibodies directed against different epitopes may be advantageous against a highly mutating virus such as HCV. Two human monoclonal antibodies (HumAbs) against the E2 envelope protein of HCV were developed and tested for the ability to neutralize the virus and prevent human liver infection. These antibodies, designated HCV-AB 68 and HCV-AB 65, recognize different conformational epitopes on E2. They were characterized in vitro biochemically and functionally. Both HumAbs are immunoglobulin G1 and have affinity constants to recombinant E2 constructs in the range of 10
−10
M. They are able to immunoprecipitate HCV particles from infected patients' sera from diverse genotypes and to stain HCV-infected human liver tissue. Both antibodies can fix complement and form immune complexes, but they do not activate complement-dependent or antibody-dependent cytotoxicity. Upon complement fixation, the monoclonal antibodies induce phagocytosis of the immune complexes by neutrophils, suggesting that the mechanism of viral clearance includes endocytosis. In vivo, in the HCV-Trimera model, both HumAbs were capable of inhibiting HCV infection of human liver fragments and of reducing the mean viral load in HCV-positive animals. The demonstrated neutralizing activities of HCV-AB 68 and HCV-AB 65 suggest that they have the potential to prevent reinfection in liver transplant patients and to serve as prophylactic treatment in postexposure events.
Replication and Clearance of Venezuelan Equine Encephalitis Virus from the Brains of Animals Vaccinated with Chimeric SIN/VEE Viruses
Authors: Paessler Slobodan , Ni Haolin , Petrakova Olga , Fayzulin Rafik Z. , Yun Nadezhda , Anishchenko Michael , Weaver Scott C. , Frolov Ilya 
Published: February 2006

ABSTRACTVenezuelan equine encephalitis virus (VEEV) is an important, naturally emerging zoonotic pathogen. Recent outbreaks in Venezuela and Colombia in 1995, involving an estimated 100,000 human cases, indicate that VEEV still poses a serious public health threat. To develop a safe, efficient vaccine that protects against disease resulting from VEEV infection, we generated chimeric Sindbis (SIN) viruses expressing structural proteins of different strains of VEEV and analyzed their replication in vitro and in vivo, as well as the characteristics of the induced immune responses. None of the chimeric SIN/VEE viruses caused any detectable disease in adult mice after either intracerebral (i.c.) or subcutaneous (s.c.) inoculation, and all chimeras were more attenuated than the vaccine strain, VEEV TC83, in 6-day-old mice after i.c. infection. All vaccinated mice were protected against lethal encephalitis following i.c., s.c., or intranasal (i.n.) challenge with the virulent VEEV ZPC738 strain (ZPC738). In spite of the absence of clinical encephalitis in vaccinated mice challenged with ZPC738 via i.n. or i.c. route, we regularly detected high levels of infectious challenge virus in the central nervous system (CNS). However, infectious virus was undetectable in the brains of all immunized animals at 28 days after challenge. Hamsters vaccinated with chimeric SIN/VEE viruses were also protected against s.c. challenge with ZPC738. Taken together, our findings suggest that these chimeric SIN/VEE viruses are safe and efficacious in adult mice and hamsters and are potentially useful as VEEV vaccines. In addition, immunized animals provide a useful model for studying the mechanisms of the anti-VEEV neuroinflammatory response, leading to the reduction of viral titers in the CNS and survival of animals.