bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell Wall Targeting of Laccase of
Cryptococcus neoformans
during Infection of Mice
Authors: Waterman Scott R. , Hacham Moshe , Panepinto John , Hu Guowu , Shin Soowan , Williamson Peter R. 
Published: November 2006

ABSTRACT

Laccase is a major virulence factor of the pathogenic fungus
Cryptococcus neoformans
, which afflicts both immunocompetent and immunocompromised individuals. In the present study, laccase was expressed in
C. neoformans lac1
Δ cells as a fusion protein with an N-terminal green fluorescent protein (GFP) using
C. neoformans
codon usage. The fusion protein was robustly localized to the cell wall at physiological pH, but it was mislocalized at low pH. Structural analysis of the laccase identified a C-terminal region unique to
C. neoformans
, and expression studies showed that the region was required for efficient transport to the cell wall both in vitro and during infection of mouse lungs. During infection of mice, adherence to alveolar macrophages was also associated with a partial mislocalization of GFP-laccase within cytosolic vesicles. In addition, recovery of cryptococcal cells from lungs of two strains of mice (CBA/J and Swiss Albino) later in infection was also associated with cytosolic mislocalization, but cells from the brain showed almost exclusive localization to cell walls, suggesting that there was more efficient cell wall targeting during infection of the brain. These data suggest that host cell antifungal defenses may reduce effective cell wall targeting of laccase during infection of the lung but not during infection of the brain, which may contribute to a more predominant role for the enzyme during infection of the brain.
Heterologous Priming-Boosting with DNA and Modified Vaccinia Virus Ankara Expressing Tryparedoxin Peroxidase Promotes Long-Term Memory againstLeishmania majorin Susceptible BALB/c Mice
Authors: Stober Carmel B. , Lange Uta G. , Roberts Mark T. M. , Alcami Antonio , Blackwell Jenefer M. 
Published: November 2006

ABSTRACTLeishmaniasis affects 12 million people, but there are no vaccines in routine clinical use. Th1 polarizing vaccines that elicit long-term protection are required to prevent disease in susceptible populations. We recently showed that heterologous priming-boosting with tryparedoxin peroxidase (TRYP) DNA followed by TRYP-modified vaccinia virus Ankara (TRYP MVA) protected susceptible BALB/c mice fromLeishmania major. Here we compared treatment with TRYP DNA with treatment with TRYP DNA/TRYP MVA. We found that equivalent levels of protection during the postvaccination effector phase correlated with equivalent levels of serum immunoglobulin G2a and gamma interferon (IFN-γ) in draining lymph nodes. In contrast, challenge infection during the memory phase revealed that there was enhanced clinical efficacy with TRYP DNA/TRYP MVA. This correlated with higher levels of effector phase splenic IFN-γ, sustained prechallenge levels of memory phase IFN-γ, and a more polarized post-L. majorchallenge Th1 response compared to the Th2/Tregresponse. Thus, TRYP DNA/TRYP MVA, but not TRYP DNA alone, provides long-term protection against murine leishmaniasis.
Trefoil Family Factor 2 Is Expressed in Murine Gastric and Immune Cells and Controls both Gastrointestinal Inflammation and Systemic Immune Responses
Authors: Kurt-Jones Evelyn A. , Cao LuCheng , Sandor Frantisek , Rogers Arlin B. , Whary Mark T. , Nambiar Prashant R. , Cerny Anna , Bowen Glennice , Yan Jing , Takaishi Shigeo , Chi Alfred L. , Reed George , Houghton JeanMarie , Fox James G. , Wang Timothy C. 
Published: November 2006

ABSTRACT

Trefoil family factor 2 (TFF2), also known as spasmolytic peptide, is a low-molecular-weight protein that is upregulated in gastric tissues infected with
Helicobacter
or having other inflammatory conditions, but a precise function is yet to be elucidated. The role of TFF2 in the development of gastritis, colitis, and inflammatory cytokine responses was examined both in vivo and in vitro using wild-type and TFF2 knockout mice. TFF2 knockout and wild-type mice were infected with
Helicobacter felis (H. felis
) to induce gastritis. Colitis was induced in TFF2 knockout and wild-type mice by administering dextran sodium sulfate (DSS) in drinking water. Histopathology, clinical disease (colitis), and antibody levels (
H. felis
) were examined. TFF2 expression in tissues was determined by reverse transcriptase PCR, and the inflammatory and proliferative responses of TFF2-expressing macrophages and spleen cells were examined by cytokine enzyme-linked immunosorbent assay, thymidine incorporation, and gene array studies. TFF2 knockout mice have increased susceptibility to
H. felis
-induced gastritis, with enhanced gastric inflammation. They were also more susceptible to DSS-induced colitis, with prolonged colonic hemorrhage and persistent weight loss. Remarkably, TFF2 expression was not limited to the gastrointestinal tract, as suggested in previous studies, but was also present in macrophages and lymphocytes. The inflammatory and proliferative responses of these immune cell types were dysregulated in TFF2 knockout mice. TFF2
−/−
cells were hyperresponsive to interleukin 1 beta stimulation but showed normal responses to lipopolysaccharide, suggesting a specific role for TFF2 in interleukin 1 receptor but not Toll-like receptor 4 signaling via their Toll-interleukin 1 resistance domains. TFF2
−/−
lymphocytes also produced higher levels of interleukin 2 than wild-type cells. Thus, TFF2 was expressed in the gastrointestinal cells and in immune cells and was a negative regulator of gastrointestinal inflammation and immune cell cytokine responses. Our studies suggest that TFF2 not only controls gastrointestinal repair but also regulates mononuclear cell inflammatory responses.
The Thiol:Disulfide Oxidoreductase DsbB Mediates the Oxidizing Effects of the Toxic Metalloid Tellurite (TeO32−) on the Plasma Membrane Redox System of the Facultative PhototrophRhodobacter capsulatus
Authors: Borsetti Francesca , Francia Francesco , Turner Raymond J. , Zannoni Davide 
Published: November 2006

ABSTRACTThe highly toxic oxyanion tellurite (TeO32−) is a well known pro-oxidant in mammalian and bacterial cells. This work examines the effects of tellurite on the redox state of the electron transport chain of the facultative phototrophRhodobacter capsulatus, in relation to the role of the thiol:disulfide oxidoreductase DsbB. Under steady-state respiration, the addition of tellurite (2.5 mM) to membrane fragments generated an extrareduction of the cytochrome pool (c- andb-type hemes); further, in plasma membranes exposed to tellurite (0.25 to 2.5 mM) and subjected to a series of flashes of light, the rate of the QH2:cytochromec(Cytc) oxidoreductase activity was enhanced. The effect of tellurite was blocked by the antibiotics antimycin A and/or myxothiazol, specific inhibitors of the QH2:Cytcoxidoreductase, and, most interestingly, the membrane-associated thiol:disulfide oxidoreductase DsbB was required to mediate the redox unbalance produced by the oxyanion. Indeed, this phenomenon was absent fromR. capsulatusMD22, a DsbB-deficient mutant, whereas the tellurite effect was present in membranes from MD22/pDsbBWT, in which the mutant gene was complemented to regain the wild-type DsbB phenotype. These findings were taken as evidence that the membrane-bound thiol:disulfide oxidoreductase DsbB acts as an “electron conduit” between the hydrophilic metalloid and the lipid-embedded Q pool, so that in habitats contaminated with subinhibitory amounts of TeIV, the metalloid is likely to function as a disposal for the excess reducing power at the Q-pool level of facultative phototrophic bacteria.
Borrelia burgdorferi
Alters Its Gene Expression and Antigenic Profile in Response to CO
2
Levels
Authors: Hyde Jenny A. , Trzeciakowski Jerome P. , Skare Jonathan T. 
Published: November 2006

ABSTRACT

The etiologic agent of Lyme disease,
Borrelia burgdorferi
, must adapt to the distinct environments of its arthropod vector and mammalian host during its complex life cycle.
B. burgdorferi
alters gene expression and protein synthesis in response to temperature, pH, and other uncharacterized environmental factors. The hypothesis tested in this study is that dissolved gases, including CO
2
, serve as a signal for
B. burgdorferi
to alter protein production and gene expression. In this study we focused on characterization of in vitro anaerobic (5% CO
2
, 3% H
2
, 0.087 ppm O
2
) and microaerophilic (1% CO
2
, 3.48 ppm O
2
) growth conditions and how they modulate protein synthesis and gene expression in
B. burgdorferi
. Higher levels of several immunoreactive proteins, including BosR, NapA, DbpA, OspC, BBK32, and RpoS, were synthesized under anaerobic conditions. Previous studies demonstrated that lower levels of NapA were produced when microaerophilic cultures were purged with nitrogen gas to displace oxygen and CO
2
. In this study we identified CO
2
as a factor contributing to the observed change in NapA synthesis. Specifically, a reduction in the level of dissolved CO
2
, independent of O
2
levels, resulted in reduced NapA synthesis. BosR, DbpA, OspC, and RpoS synthesis was also decreased with the displacement of CO
2
. Quantitative reverse transcription-PCR indicated that the levels of the
dbpA
,
ospC
, and BBK32 transcripts are increased in the presence of CO
2
, indicating that these putative borrelial virulence determinants are regulated at the transcriptional level. Thus, dissolved CO
2
may be an additional cue for borrelial host adaptation and gene regulation.
Respiratory Nitrate Ammonification byShewanella oneidensisMR-1
Authors: Cruz-García Claribel , Murray Alison E. , Klappenbach Joel A. , Stewart Valley , Tiedje James M. 
Published: November 2006

ABSTRACTAnaerobic cultures ofShewanella oneidensisMR-1 grown with nitrate as the sole electron acceptor exhibited sequential reduction of nitrate to nitrite and then to ammonium. Little dinitrogen and nitrous oxide were detected, and no growth occurred on nitrous oxide. A mutant with thenapAgene encoding periplasmic nitrate reductase deleted could not respire or assimilate nitrate and did not express nitrate reductase activity, confirming that the NapA enzyme is the sole nitrate reductase. Hence,S. oneidensisMR-1 conducts respiratory nitrate ammonification, also termed dissimilatory nitrate reduction to ammonium, but not respiratory denitrification.
Role of Gne and GalE in the Virulence of
Aeromonas hydrophila
Serotype O34
Authors: Canals Rocío , Jiménez Natalia , Vilches Silvia , Regué Miguel , Merino Susana , Tomás Juan M. 
Published: November 2006

ABSTRACT

The mesophilic
Aeromonas hydrophila
AH-3 (serotype O34) strain shows two different UDP-hexose epimerases in its genome: GalE (EC 3.1.5.2) and Gne (EC 3.1.5.7). Similar homologues were detected in the different mesophilic
Aeromonas
strains tested. GalE shows only UDP-galactose 4-epimerase activity, while Gne is able to perform a dual activity (mainly UDP-
N
-acetyl galactosamine 4-epimerase and also UDP-galactose 4-epimerase). We studied the activities in vitro of both epimerases and also in vivo through the lipopolysaccharide (LPS) structure of
A. hydrophila gne
mutants,
A. hydrophila galE
mutants,
A. hydrophila galE-gne
double mutants, and independently complemented mutants with both genes. Furthermore, the enzymatic activity in vivo, which renders different LPS structures on the mentioned
A. hydrophila
mutant strains or the complemented mutants, allowed us to confirm a clear relationship between the virulence of these strains and the presence/absence of the O34 antigen LPS.
The Complete Genome Sequence of
Roseobacter denitrificans
Reveals a Mixotrophic Rather than Photosynthetic Metabolism
Authors: Swingley Wesley D. , Sadekar Sumedha , Mastrian Stephen D. , Matthies Heather J. , Hao Jicheng , Ramos Hector , Acharya Chaitanya R. , Conrad Amber L. , Taylor Heather L. , Dejesa Liza C. , Shah Maulik K. , O'Huallachain Maeve E. , Lince Michael T. , Blankenship Robert E. , Beatty J. Thomas , Touchman Jeffrey W. 
Published: November 2006

ABSTRACT

Purple aerobic anoxygenic phototrophs (AAPs) are the only organisms known to capture light energy to enhance growth only in the presence of oxygen but do not produce oxygen. The highly adaptive AAPs compose more than 10% of the microbial community in some euphotic upper ocean waters and are potentially major contributors to the fixation of the greenhouse gas CO
2
. We present the complete genomic sequence and feature analysis of the AAP
Roseobacter denitrificans
, which reveal clues to its physiology. The genome lacks genes that code for known photosynthetic carbon fixation pathways, and most notably missing are genes for the Calvin cycle enzymes ribulose bisphosphate carboxylase (RuBisCO) and phosphoribulokinase. Phylogenetic evidence implies that this absence could be due to a gene loss from a RuBisCO-containing α-proteobacterial ancestor. We describe the potential importance of mixotrophic rather than autotrophic CO
2
fixation pathways in these organisms and suggest that these pathways function to fix CO
2
for the formation of cellular components but do not permit autotrophic growth. While some genes that code for the redox-dependent regulation of photosynthetic machinery are present, many light sensors and transcriptional regulatory motifs found in purple photosynthetic bacteria are absent.
Characterization of Two Sets of Subpolar Flagella in
Bradyrhizobium japonicum
Authors: Kanbe Masaomi , Yagasaki Jin , Zehner Susanne , Göttfert Michael , Aizawa Shin-Ichi 
Published: November 2006

ABSTRACT

Bradyrhizobium japonicum
is one of the soil bacteria that form nodules on soybean roots. The cell has two sets of flagellar systems, one thick flagellum and a few thin flagella, uniquely growing at subpolar positions. The thick flagellum appears to be semicoiled in morphology, and the thin flagella were in a tight-curly form as observed by dark-field microscopy. Flagellin genes were identified from the amino acid sequence of each flagellin. Flagellar genes for the thick flagellum are scattered into several clusters on the genome, while those genes for the thin flagellum are compactly organized in one cluster. Both types of flagella are powered by proton-driven motors. The swimming propulsion is supplied mainly by the thick flagellum.
B. japonicum
flagellar systems resemble the polar-lateral flagellar systems of
Vibrio
species but differ in several aspects.
Contribution of Invariant Residues to the Function of Rgg Family Transcription Regulators
Authors: Loughman Jennifer A. , Caparon Michael G. 
Published: November 2006

ABSTRACTThe Rgg family of transcription regulators is widely distributed among gram-positive bacteria, yet how these proteins control transcription is poorly understood. UsingStreptococcus pyogenesRopB as a model, we demonstrated that residues invariant among Rgg-like regulators are critical for function and obtained evidence for a mechanism involving protein complex formation.
Specific Interaction between the Initiator Protein (Rep) and Origin of Plasmid ColE2-P9
Authors: Han M. , Yagura M. , Itoh T. 
Published: November 2006

ABSTRACTThe replication initiator protein (Rep) of plasmid ColE2-P9 (ColE2) is multifunctional. We are interested in how Rep binds to the origin (Ori) to perform various functions. We used the wild type and variants of Rep to study the Rep-Ori interaction by both in vitro and in vivo approaches, including biochemical analyses of protein-DNA interactions and an in vivo replication assay. We identified three regions (I, II, and III) of Rep, located in the C-terminal half, and three corresponding binding sites (I, II, and III) in Ori which are important for Rep-Ori interaction. We showed that region I, containing a putative helix-turn-helix motif, is necessary and sufficient for specific Ori recognition, interacting with site I of the origin DNA from the major groove. Region II interacts with site II of the origin DNA, from the adjacent minor groove in the left half of Ori, and region III interacts with site III, next to the template sequence for primer synthesis, which is one and one-half turn apart from site I on the opposite surface of the origin DNA. A putative linker region located between the two DNA binding domains (regions II and III) was identified, which might provide Rep an extended conformation suitable for binding to the two separate sites in Ori. Based on the results presented in this paper, we propose a model for Rep-Ori interaction in which Rep binds to Ori as a monomer.
Molecular Evolution of Typical EnteropathogenicEscherichia coli: Clonal Analysis by Multilocus Sequence Typing and Virulence Gene Allelic Profiling
Authors: Lacher David W. , Steinsland Hans , Blank T. Eric , Donnenberg Michael S. , Whittam Thomas S. 
Published: November 2006

ABSTRACTEnteropathogenicEscherichia coli(EPEC) infections are a leading cause of infantile diarrhea in developing nations. Typical EPEC isolates are differentiated from other types of pathogenicE. coliby two distinctive phenotypes, attaching effacement and localized adherence. The genes specifying these phenotypes are found on the locus of enterocyte effacement (LEE) and the EPEC adherence factor (EAF) plasmid. To describe how typical EPEC has evolved, we characterized a diverse collection of strains by multilocus sequence typing (MLST) and performed restriction fragment length polymorphism (RFLP) analysis of three virulence genes (eae,bfpA, andperA) to assess allelic variation. Among 129 strains representing 20 O-serogroups, 21 clonal genotypes were identified using MLST. RFLP analysis resolved nineeae, ninebfpA, and fourperAalleles. EachbfpAallele was associated with only oneperAallele class, suggesting that recombination has not played a large role in shuffling thebfpAandperAloci between separate EAF plasmids. The distribution ofeaealleles among typical EPEC strains is more concordant with the clonal relationships than the distribution of the EAF plasmid types. These results provide further support for the hypothesis that the EPEC pathotype has evolved multiple times withinE. colithrough separate acquisitions of the LEE island and EAF plasmid.
Reporting of ethnicity in research on chronic disease: update
Authors: O'Loughlin J , Dugas E , Maximova K , Kishchuk N 
Published: November 2006

Abstract
This paper examines the inclusion of ethnicity and race as variables in current, leading edge research on chronic disease and its risk factors. Of 100 randomly selected original research articles published in high-impact journals in 2005, 85% did not report either a definition of ethnicity or its conceptualisation in terms of theoretical reasoning, and 98% did not report an actual measurement item. Ethnicity and race remain non-standardised and largely underdescribed variables in research on chronic disease. This represents an important loss of opportunity to articulate and test hypotheses about the mechanisms underlying ethnic group differences in chronic disease.
Post lumbar puncture headache: diagnosis and management
Authors: Ahmed S V , Jayawarna C , Jude E 
Published: November 2006

Abstract
Lumbar puncture is a frequently performed procedure in medical emergencies and anaesthesia. Headache after lumbar puncture is a common occurrence (32%) and carries a considerable morbidity, with symptoms lasting for several days, at times severe enough to immobilise the patient. If untreated, it can result in serious complications such as subdural haematoma and seizures, which could be fatal. Certain factors contribute to the development of headache after lumbar puncture. If these factors are taken into consideration, the incidence of headache could be markedly reduced. It is therefore important that the doctors are aware of the methods available for reducing the incidence of headaches after lumbar puncture. On the other hand, there are several misconceptions that are thought to decrease the incidence of headaches with no scientific basis. This article reviews the scientific literature and highlights the practical issues involved in the diagnosis and management of headaches after lumbar puncture, including the epidural blood patch treatment.
Complications of coeliac disease: are all patients at risk?
Authors: Goddard C J R , Gillett H R 
Published: November 2006

Abstract
Coeliac disease is a common condition that is increasingly being recognised as a result of the development of sensitive and specific serology. The diagnosis of coeliac disease and its subsequent treatment with a gluten-free diet have implications for the patient, not just for symptom control but also for the possible effect on quality of life and risk of complications. Whether the mode of presentation of coeliac disease has an effect on survival or risk of complication is yet unclear. This article reviews the available evidence regarding these issues.
Sexually transmitted proctitis
Authors: Hamlyn E , Taylor C 
Published: November 2006

Abstract
Sexually transmitted infections such as chlamydia, gonorrhoea, herpes simplex virus and syphilis commonly present with rectal symptoms. Recent outbreaks of lymphogranuloma venereum among homosexual men throughout Europe highlight the need to consider sexually transmitted infections in the differential diagnosis of proctitis. This article examines the causative organisms, clinical features, diagnosis and treatment of sexually transmitted proctitis.
CROWELL'S DERIVED GROUP AND TWISTED POLYNOMIALS
Authors: SILVER DANIEL S. , WILLIAMS SUSAN G. 
Published: November 2006

The derived group of a permutation representation, introduced by Crowell, unites many notions of knot theory. We survey Crowell's construction, and offer new applications.The twisted Alexander group of a knot is defined. Using it, we obtain twisted Alexander polynomials. Also, we extend a well-known theorem of Neuwirth and Stallings giving necessary and sufficient conditions for a knot to be fibered.Virtual Alexander polynomials provide obstructions for a virtual knot that must vanish if the knot has a diagram with an Alexander numbering. The extended group of a virtual knot is defined, and using it a more sensitive obstruction is obtained.
DESIGN AS AN ELEMENT OF INNOVATION: EVALUATING DESIGN EMPHASIS IN TECHNOLOGY-BASED FIRMS
Authors: CANDI MARINA 
Published: November 2006

Design is increasingly gaining recognition as a fruitful means to improve business performance. Technology-based firms are an important source of innovation, and therefore it is important to develop a means to study the relationship between technology-based firms' emphasis on design as an element of innovation and their performance. This article develops a model for evaluating technology-based firms' design emphasis. The model is based on a synthesis approach to studying innovation in both services and manufacturing and a three-dimensional definition of design. The application of the model is demonstrated using a set of new technology-based firms. The empirical study confirms the appropriateness of using the synthesis approach for studying design as an element of innovation in technology-based firms. The application of the model provides a classification which can be used as a basis for studying the relationship between design emphasis and performance.