bluuebunny/crossref_metadata_2025_split huggingface dataset:
A (p)ppGpp-Null Mutant of Haemophilus ducreyi Is Partially Attenuated in Humans Due to Multiple Conflicting Phenotypes
Authors: Holley Concerta , Gangaiah Dharanesh , Li Wei , Fortney Kate R. , Janowicz Diane M. , Ellinger Sheila , Zwickl Beth , Katz Barry P. , Spinola Stanley M. 
Published: June 2014

ABSTRACT

(p)ppGpp responds to nutrient limitation through a global change in gene regulation patterns to increase survival. The stringent response has been implicated in the virulence of several pathogenic bacterial species.
Haemophilus ducreyi
, the causative agent of chancroid, has homologs of both
relA
and
spoT
, which primarily synthesize and hydrolyze (p)ppGpp in
Escherichia coli
. We constructed
relA
and
relA spoT
deletion mutants to assess the contribution of (p)ppGpp to
H. ducreyi
pathogenesis. Both the
relA
single mutant and the
relA spoT
double mutant failed to synthesize (p)ppGpp, suggesting that
relA
is the primary synthetase of (p)ppGpp in
H. ducreyi
. Compared to the parent strain, the double mutant was partially attenuated for pustule formation in human volunteers. The double mutant had several phenotypes that favored attenuation, including increased sensitivity to oxidative stress. The increased sensitivity to oxidative stress could be complemented in
trans
. However, the double mutant also exhibited phenotypes that favored virulence. When grown to the mid-log phase, the double mutant was significantly more resistant than its parent to being taken up by human macrophages and exhibited increased transcription of
lspB
, which is involved in resistance to phagocytosis. Additionally, compared to the parent, the double mutant also exhibited prolonged survival in the stationary phase. In
E. coli
, overexpression of DksA compensates for the loss of (p)ppGpp; the
H. ducreyi
double mutant expressed higher transcript levels of
dksA
than the parent strain. These data suggest that the partial attenuation of the double mutant is likely the net result of multiple conflicting phenotypes.
Superantigens Subvert the Neutrophil Response To Promote Abscess Formation and Enhance Staphylococcus aureus SurvivalIn Vivo
Authors: Xu Stacey X. , Gilmore Kevin J. , Szabo Peter A. , Zeppa Joseph J. , Baroja Miren L. , Haeryfar S. M. Mansour , McCormick John K. 
Published: June 2014

ABSTRACTStaphylococcus aureusis a versatile bacterial pathogen that produces T cell-activating toxins known as superantigens (SAgs). Although excessive immune activation by SAgs can induce a dysregulated cytokine storm as a component of what is known as toxic shock syndrome (TSS), the contribution of SAgs to the staphylococcal infection process is not well defined. Here, we evaluated the role of the bacterial superantigen staphylococcal enterotoxin A (SEA) in a bacteremia model using humanized transgenic mice expressing SAg-responsive HLA-DR4 molecules. Infection withS. aureusNewman induced SEA-dependent Vβ skewing of T cells and enhanced bacterial survival in the liver compared with infection byseaknockout strain. SEA-induced gamma interferon, interleukin-12, and chemokine responses resulted in increased infiltration of CD11b+Ly6G+neutrophils into the liver, promoting the formation of abscesses that contained large numbers of viable staphylococci. Hepatic abscesses occurred significantly more frequently inS. aureusNewman-infected livers than in livers infected with the Newmanseaknockout strain, promoting the survival ofS. aureusin vivo. This represents a novel mechanism during infection wherebyS. aureusutilizes SAgs to form a specialized niche and manipulate the immune system.
Differential Effects of Escherichia coli Subtilase Cytotoxin and Shiga Toxin 2 on Chemokine and Proinflammatory Cytokine Expression in Human Macrophage, Colonic Epithelial, and Brain Microvascular Endothelial Cell Lines
Authors: Wang Hui , Rogers Trisha J. , Paton James C. , Paton Adrienne W. 
Published: June 2014

ABSTRACT

Subtilase cytotoxin (SubAB) is the prototype of a recently emerged family of AB5 cytotoxins produced by Shiga-toxigenic
Escherichia coli
(STEC). Its mechanism of action involves highly specific A-subunit-mediated proteolytic cleavage of the essential endoplasmic reticulum (ER) chaperone BiP. Our previous
in vivo
studies showed that intraperitoneal injection of purified SubAB causes a major redistribution of leukocytes and elevated leukocyte apoptosis in mice, as well as profound splenic atrophy. In the current study, we investigated selected chemokine and proinflammatory cytokine responses to treatment with SubAB, a nontoxic derivative (SubA
A272
B), or Shiga toxin 2 (Stx2) in human macrophage (U937), brain microvascular endothelial (HBMEC), and colonic epithelial (HCT-8) cell lines, at the levels of secreted protein, cell-associated protein, and gene expression. Stx2 treatment upregulated expression of chemokines and cytokines at both the protein and mRNA levels. In contrast, SubAB induced significant decreases in secreted interleukin-8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) in all three tested cell lines and a significant decrease in secreted IL-6 in HBMECs. The downregulation of secreted chemokines or cytokines was not observed in SubA
A272
B-treated cells, indicating a requirement for BiP cleavage. The downregulation of secreted chemokines and cytokines by SubAB was not reflected at the mRNA and cell-associated protein levels, suggesting a SubAB-induced export defect.
The Ctp Type IVb Pilus Locus of Agrobacterium tumefaciens Directs Formation of the Common Pili and Contributes to Reversible Surface Attachment
Authors: Wang Yi , Haitjema Charles H. , Fuqua Clay 
Published: June 2014

ABSTRACT

Agrobacterium tumefaciens
can adhere to plant tissues and abiotic surfaces and forms biofilms. Cell surface appendages called pili play an important role in adhesion and biofilm formation in diverse bacterial systems. The
A. tumefaciens
C58 genome sequence revealed the presence of the
ctpABCDEFGHI
genes (
c
luster of
t
ype IV
p
ili; Atu0216 to Atu0224), homologous to
tad
-type pilus systems from several bacteria, including
Aggregatibacter actinomycetemcomitans
and
Caulobacter crescentus
. These systems fall into the type IVb pilus group, which can function in bacterial adhesion. Transmission electron microscopy of
A. tumefaciens
revealed the presence of filaments, significantly thinner than flagella and often bundled, associated with cell surfaces and shed into the external milieu. In-frame deletion mutations of all of the
ctp
genes, with the exception of
ctpF
, resulted in nonpiliated derivatives. Mutations in
ctpA
(a pilin homologue),
ctpB
, and
ctpG
decreased early attachment and biofilm formation. The adherence of the
ctpA
mutant could be restored by ectopic expression of the paralogous
pilA
gene. The Δ
ctpA
Δ
pilA
double pilin mutant displayed a diminished biovolume and lower biofilm height than the wild type under flowing conditions. Surprisingly, however, the
ctpCD
,
ctpE
,
ctpF
,
ctpH
, and
ctpI
mutants formed normal biofilms and showed enhanced reversible attachment. In-frame deletion of the
ctpA
pilin gene in the
ctpCD
,
ctpE
,
ctpF
,
ctpH
, and
ctpI
mutants caused the same attachment-deficient phenotype as the
ctpA
single mutant. Collectively, these findings indicate that the
ctp
locus is involved in pilus assembly and that nonpiliated mutants, which retain the CtpA pilin, are proficient in attachment and adherence.
Transcription of the Lysine-2,3-Aminomutase Gene in the
kam
Locus of Bacillus thuringiensis subsp. kurstaki HD73 Is Controlled by Both σ
54
and σ
K
Factors
Authors: Zhang Zhe , Yang Min , Peng Qi , Wang Guannan , Zheng Qingyun , Zhang Jie , Song Fuping 
Published: June 2014

ABSTRACT

Lysine 2,3-aminomutase (KAM; EC 5.4.3.2) catalyzes the interconversion of
l
-lysine and
l
-β-lysine. The transcription and regulation of the
kam
locus, including lysine-2,3-aminomutase-encoding genes, in
Bacillus thuringiensis
were analyzed in this study. Reverse transcription-PCR (RT-PCR) analysis revealed that this locus forms two operons:
yodT
(
yodT-yodS-yodR-yodQ-yodP-kamR
) and
kamA
(
kamA-yokU-yozE
). The transcriptional start sites (TSSs) of the
kamA
gene were determined using 5′ rapid amplification of cDNA ends (RACE). A typical −12/−24 σ
54
binding site was identified in the promoter P

kamA

, which is located upstream of the
kamA
gene TSS. A β-galactosidase assay showed that P

kamA

, which directs the transcription of the
kamA
operon, is controlled by the σ
54
factor and is activated through the σ
54
-dependent transcriptional regulator KamR. The
kamA
operon is also controlled by σ
K
and regulated by the GerE protein in the late stage of sporulation.
kamR
and
kamA
mutants were prepared by homologous recombination to examine the role of the
kam
locus. The results showed that the sporulation rate in
B. thuringiensis
HD(Δ
kamR
) was slightly decreased compared to that in HD73, whereas that in HD(Δ
kamA
) was similar to that in HD73. This means that other genes regulated by KamR are important for sporulation.
Prevalence of prediabetes in England from 2003 to 2011: population-based, cross-sectional study
Authors: Mainous Arch G , Tanner Rebecca J , Baker Richard , Zayas Cilia E , Harle Christopher A 
Published: June 2014

ObjectivePrediabetes is a high-risk state for developing diabetes and associated complications. The purpose of this paper was to report trends in prevalence of prediabetes for individuals aged 16 and older in England without previously diagnosed diabetes.SettingData collected by the Health Survey for England (HSE) in England in the years 2003, 2006, 2009 and 2011.ParticipantsIndividuals aged 16 and older who participated in the HSE and provided a blood sample.Primary outcome variableIndividuals were classified as having prediabetes if glycated haemoglobin was between 5.7% and 6.4% and were not previously diagnosed with diabetes.ResultsThe prevalence rate of prediabetes increased from 11.6% to 35.3% from 2003 to 2011. By 2011, 50.6% of the population who were overweight (body mass index (BMI)>25) and ≥40 years of age had prediabetes. In bivariate relationships, individuals with greater socioeconomic deprivation were more likely to have prediabetes in 2003 (p=0.0008) and 2006 (p=0.0246), but the relationship was not significant in 2009 (p=0.213) and 2011 (p=0.3153). In logistic regressions controlling for age, sex, race/ethnicity, BMI and high blood pressure, the second most socioeconomically deprived had a significantly elevated risk of having prediabetes (2011, OR=1.45; 95% CI 1.26 to 1.88).ConclusionsThere has been a marked increase in the proportion of adults in England with prediabetes. The socioeconomically deprived are at substantial risk. In the absence of concerted and effective efforts to reduce risk, the number of people with diabetes is likely to increase steeply in coming years.
Determinants of treatment plan implementation in multidisciplinary team meetings for patients with chronic diseases: a mixed-methods study
Authors: Raine Rosalind , Xanthopoulou Penny , Wallace Isla , Nic a’ Bháird Caoimhe , Lanceley Anne , Clarke Alex , Livingston Gill , Prentice Archie , Ardron Dave , Harris Miriam , King Michael , Michie Susan , Blazeby Jane M , Austin-Parsons Natalie , Gibbs Simon , Barber Julie 
Published: June 2014

ObjectiveMultidisciplinary team (MDT) meetings are assumed to produce better decisions and are extensively used to manage chronic disease in the National Health Service (NHS). However, evidence for their effectiveness is mixed. Our objective was to investigate determinants of MDT effectiveness by examining factors influencing the implementation of MDT treatment plans. This is a proxy measure of effectiveness, because it lies on the pathway to improvements in health, and reflects team decision making which has taken account of clinical and non-clinical information. Additionally, this measure can be compared across MDTs for different conditions.MethodsWe undertook a prospective mixed-methods study of 12 MDTs in London and North Thames. Data were collected by observation of 370 MDT meetings, interviews with 53 MDT members, and from 2654 patient medical records. We examined the influence of patient-related factors (disease, age, sex, deprivation, whether their preferences and other clinical/health behaviours were mentioned) and MDT features (as measured using the ‘Team Climate Inventory’ and skill mix) on the implementation of MDT treatment plans.ResultsThe adjusted odds (or likelihood) of implementation was reduced by 25% for each additional professional group represented at the MDT meeting. Implementation was more likely in MDTs with clear goals and processes and a good ‘Team Climate’ (adjusted OR 1.96; 95% CI 1.15 to 3.31 for a unit increase in Team Climate Inventory (TCI) score). Implementation varied by disease category, with the lowest adjusted odds of implementation in mental health teams. Implementation was also lower for patients living in more deprived areas (adjusted odds of implementation for patients in the most compared with least deprived areas was 0.60, 95% CI 0.39 to 0.91).ConclusionsGreater multidisciplinarity is not necessarily associated with more effective decision making. Explicit goals and procedures are also crucial. Decision implementation should be routinely monitored to ensure the equitable provision of care.
MicroRNA as potential biomarker in HCV-associated diffuse large B-cell lymphoma
Authors: Augello Claudia , Gianelli Umberto , Savi Federica , Moro Alessia , Bonoldi Emanuela , Gambacorta Marcello , Vaira Valentina , Baldini Luca , Bosari Silvano 
Published: June 2014

AimsTo identify molecular characteristics to hepatitis C virus (HCV)-associated diffuse large B-cell lymphoma (DLBCL) through a comprehensive miRNAs expression profiling.MethodsIn this study, miRNA profiles were obtained from 37 patients with DLBCLs and 60 patients with reactive lymph nodes, equally distributed according to HCV presence. Germinal centres, from reactive lymph nodes were used as controls. Clinical features at presentation were available for all patients.ResultsA set of 52 miRNAs define a signature for HCV-associated DLBCL. Importantly, decreased expression of miR-138-5p and increased expression of miR-147a, miR-147b and miR-511-5p in HCV DLBCL was found to be a poor prognostic factor for HCV-positive DLBCL patients.ConclusionsThese data reveal molecular differences in diffuse DLBCL patients according to HCV presence, potentially useful as novel prognostic or therapeutic biomarkers.
Pathogenic autoantibodies from patients with lupus nephritis cause reduced tyrosine phosphorylation of podocyte proteins, including tubulin
Authors: Manson Jessica J , Mills Kevin , Jury Elizabeth , Mason Lesley , D'Cruz David P , Ni Lan , Saleem Moin , Mathieson Peter , Isenberg David , Rahman Anisur 
Published: June 2014

IntroductionThe tertiary structure of normal podocytes prevents protein from leaking into urine. Patients with lupus nephritis (LN) develop proteinuria, and kidney biopsies from these patients display a number of podocyte abnormalities including retraction of podocyte processes. Autoantibodies have been shown to deposit in the kidneys of patients and mice with LN and are believed to play a key role in causing renal inflammation and dysfunction. The objective of this research was to study the effects of IgG antibodies from patients with LN on cultured human podocytes.MethodsWe exposed a human podocyte cell line to heat-inactivated (HI) plasma and purified polyclonal IgG from the following groups of subjects; patients with LN, patients with lupus without nephritis, patients with rheumatoid arthritis and healthy controls. We measured expression and intracellular distribution of podocyte-specific proteins and global phosphorylation of tyrosine. We then used mass spectrometry to identify the major protein targets of this phosphorylation.ResultsHI LN plasma did not alter expression or cellular distribution of podocyte-specific proteins but caused a significant reduction in podocyte protein tyrosine phosphorylation compared with plasma from healthy controls (p=0.0008). This result was replicated using purified IgG but was not seen with plasma from rheumatoid arthritis or non-renal lupus patients. The dominant tyrosine phosphorylated protein in podocytes was 55 kDa in size and was identified as tubulin.ConclusionsSince tubulin is an important component of podocyte major processes, these results suggest that autoantibodies from LN patients may exert an important pathogenic effect by dephosphorylation of this protein in podocytes.
Adverse pregnancy outcomes and subsequent risk of cardiovascular disease in women with systemic lupus erythematosus
Authors: Lin Pin , Rhew Elisa , Ness Roberta B , Peaceman Alan , Dyer Alan , McPherson David , Kondos George T , Edmundowicz Daniel , Sutton-Tyrrell Kim , Thompson Trina , Ramsey-Goldman Rosalind 
Published: June 2014

Background/objectivePatients with systemic lupus erythematosus (SLE) are at increased risk for adverse pregnancy outcomes and cardiovascular disease (CVD). The objective of this exploratory study was to investigate the association between a history of adverse pregnancy outcomes and subsequent risk of subclinical CVD assessed by imaging studies and verified clinical CVD events in 129 women with SLE.MethodsThe occurrence of adverse pregnancy outcomes, specifically pre-eclampsia, preterm birth and low birth weight was ascertained by questionnaire. Subclinical CVD was assessed by coronary artery calcium (CAC) as measured by electron beam CT and carotid plaque measured by B mode ultrasound. Clinical CVD events were verified by medical record review. Logistic regression was used to estimate the association of pregnancy complications with occurrence of subclinical CVD and clinical CVD with a priori adjustment for age, which is associated with CVD and SLE disease duration as a measure of SLE disease burden.ResultsFifty-six women reported at least one pregnancy complication while 73 had none. Twenty-six women had at least one pregnancy complicated by pre-eclampsia and were more likely to have a CAC score greater than or equal to 10 (adjusted OR=3.7; 95% CI 1.2 to 11.9), but the presence of plaque was not associated with this pregnancy complication, OR=1.1, (95% CI 0.4 to 2.8). Low birth weight and preterm birth were not associated with CAC or plaque.ConclusionsPatients with SLE with a history of pre-eclampsia had a higher rate of subclinical CVD as measured by CAC score. Future studies are needed to confirm the relationship between adverse pregnancy outcomes and subsequent subclinical CVD and clinical CVD events.
Cumulative Radiation Exposure and Cancer Risk Estimation in Children With Heart Disease
Authors: Johnson Jason N. , Hornik Christoph P. , Li Jennifer S. , Benjamin Daniel K. , Yoshizumi Terry T. , Reiman Robert E. , Frush Donald P. , Hill Kevin D 
Published: June 2014

Background—
Children with heart disease are frequently exposed to imaging examinations that use ionizing radiation. Although radiation exposure is potentially carcinogenic, there are limited data on cumulative exposure and the associated cancer risk. We evaluated the cumulative effective dose of radiation from all radiation examinations to estimate the lifetime attributable risk of cancer in children with heart disease.

Methods and Results—

Children ≤6 years of age who had previously undergone 1 of 7 primary surgical procedures for heart disease at a single institution between 2005 and 2010 were eligible for the study. Exposure to radiation-producing examinations was tabulated, and cumulative effective dose was calculated in millisieverts. These data were used to estimate lifetime attributable risk of cancer above baseline using the approach of the Committee on Biological Effects of Ionizing Radiation VII. The cohort included 337 children exposed to 13 932 radiation examinations. Conventional radiographs represented 92% of examinations, whereas cardiac catheterization and computed tomography accounted for 81% of cumulative exposure. Overall median cumulative effective dose was 2.7 mSv (range, 0.1–76.9 mSv), and the associated lifetime attributable risk of cancer was 0.07% (range, 0.001%–6.5%). Median lifetime attributable risk of cancer ranged widely depending on surgical complexity (0.006%–1.6% for the 7 surgical cohorts) and was twice as high in females per unit exposure (0.04% versus 0.02% per 1-mSv effective dose for females versus males, respectively;
P
<0.001).

Conclusions—
Overall radiation exposures in children with heart disease are relatively low; however, select cohorts receive significant exposure. Cancer risk estimation highlights the need to limit radiation dose, particularly for high-exposure modalities.
A GSI-Based Coupled EnSRF–En3DVar Hybrid Data Assimilation System for the Operational Rapid Refresh Model: Tests at a Reduced Resolution
Authors: Pan Yujie , Zhu Kefeng , Xue Ming , Wang Xuguang , Hu Ming , Benjamin Stanley G. , Weygandt Stephen S. , Whitaker Jeffrey S. 
Published: June 2014

Abstract
A coupled ensemble square root filter–three-dimensional ensemble-variational hybrid (EnSRF–En3DVar) data assimilation (DA) system is developed for the operational Rapid Refresh (RAP) forecasting system. The En3DVar hybrid system employs the extended control variable method, and is built on the NCEP operational gridpoint statistical interpolation (GSI) three-dimensional variational data assimilation (3DVar) framework. It is coupled with an EnSRF system for RAP, which provides ensemble perturbations. Recursive filters (RF) are used to localize ensemble covariance in both horizontal and vertical within the En3DVar. The coupled En3DVar hybrid system is evaluated with 3-h cycles over a 9-day period with active convection. All conventional observations used by operational RAP are included. The En3DVar hybrid system is run at ⅓ of the operational RAP horizontal resolution or about 40-km grid spacing, and its performance is compared to parallel GSI 3DVar and EnSRF runs using the same datasets and resolution. Short-term forecasts initialized from the 3-hourly analyses are verified against sounding and surface observations. When using equally weighted static and ensemble background error covariances and 40 ensemble members, the En3DVar hybrid system outperforms the corresponding GSI 3DVar and EnSRF. When the recursive filter coefficients are tuned to achieve a similar height-dependent localization as in the EnSRF, the En3DVar results using pure ensemble covariance are close to EnSRF. Two-way coupling between EnSRF and En3DVar did not produce noticeable improvement over one-way coupling. Downscaled precipitation forecast skill on the 13-km RAP grid from the En3DVar hybrid is better than those from GSI 3DVar analyses.