bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification and Regulation of a Novel Citrobacter rodentium Gut Colonization Fimbria (Gcf)
Authors: Caballero-Flores Gustavo G. , Croxen Matthew A. , Martínez-Santos Verónica I. , Finlay B. Brett , Puente José L. 
Published: February 2015

ABSTRACT

The Gram-negative enteric bacterium
Citrobacter rodentium
is a natural mouse pathogen that has been extensively used as a surrogate model for studying the human pathogens enteropathogenic and enterohemorrhagic
Escherichia coli
. All three pathogens produce similar attaching and effacing (A/E) lesions in the intestinal epithelium. During infection, these bacteria employ surface structures called fimbriae to adhere and colonize the host intestinal epithelium. For
C. rodentium
, the roles of only a small number of its genome-carried fimbrial operons have been evaluated. Here, we report the identification of a novel
C. rodentium
colonization factor, called
g
ut
c
olonization
f
imbria (Gcf), which is encoded by a chaperone-usher fimbrial operon. A
gcfA
mutant shows a severe colonization defect within the first 10 days of infection. The
gcf
promoter is not active in
C. rodentium
under several
in vitro
growth conditions; however, it is readily expressed in a
C. rodentium
Δ
hns1
mutant lacking the closest ortholog of the
Escherichia coli
histone-like nucleoid structuring protein (H-NS) but not in mutants with deletion of the other four genes encoding H-NS homologs. H-NS binds to the regulatory region of
gcf
, further supporting its direct role as a repressor of the
gcf
promoter that starts transcription 158 bp upstream of the start codon of its first open reading frame. The
gcf
operon possesses interesting novel traits that open future opportunities to expand our knowledge of the structure, regulation, and function during infection of these important bacterial structures.

IMPORTANCE
Fimbriae are surface bacterial structures implicated in a variety of biological processes. Some have been shown to play a critical role during host colonization and thus in disease. Pathogenic bacteria possess the genetic information for an assortment of fimbriae, but their function and regulation and the interplay between them have not been studied in detail. This work provides new insights into the function and regulation of a novel fimbria called Gcf that is important for early establishment of a successful infection by
C. rodentium
in mice, despite being poorly expressed under
in vitro
growth conditions. This discovery offers an opportunity to better understand the individual role and the regulatory mechanisms controlling the expression of specific fimbrial operons that are critical during infection.
The Bacterial Alarmone (p)ppGpp Activates the Type III Secretion System in Erwinia amylovora
Authors: Ancona Veronica , Lee Jae Hoon , Chatnaparat Tiyakhon , Oh Jinrok , Hong Jong-In , Zhao Youfu 
Published: February 2015

ABSTRACT

The hypersensitive response and pathogenicity (
hrp
) type III secretion system (T3SS) is a key pathogenicity factor in
Erwinia amylovora
. Previous studies have demonstrated that the T3SS in
E. amylovora
is transcriptionally regulated by a sigma factor cascade. In this study, the role of the bacterial alarmone ppGpp in activating the T3SS and virulence of
E. amylovora
was investigated using ppGpp mutants generated by Red recombinase cloning. The virulence of a ppGpp-deficient mutant (ppGpp
0
) as well as a
dksA
mutant of
E. amylovora
was completely impaired, and bacterial growth was significantly reduced, suggesting that ppGpp is required for full virulence of
E. amylovora
. Expression of T3SS genes was greatly downregulated in the ppGpp
0
and
dksA
mutants. Western blotting showed that accumulations of the HrpA protein in the ppGpp
0
and
dksA
mutants were about 10 and 4%, respectively, of that in the wild-type strain. Furthermore, higher levels of ppGpp resulted in a reduced cell size of
E. amylovora
. Moreover, serine hydroxamate and α-methylglucoside, which induce amino acid and carbon starvation, respectively, activated
hrpA
and
hrpL
promoter activities in
hrp
-inducing minimal medium. These results demonstrated that ppGpp and DksA play central roles in
E. amylovora
virulence and indicated that
E. amylovora
utilizes ppGpp as an internal messenger to sense environmental/nutritional stimuli for regulation of the T3SS and virulence.

IMPORTANCE
The type III secretion system (T3SS) is a key pathogenicity factor in Gram-negative bacteria. Fully elucidating how the T3SS is activated is crucial for comprehensively understanding the function of the T3SS, bacterial pathogenesis, and survival under stress conditions. In this study, we present the first evidence that the bacterial alarmone ppGpp-mediated stringent response activates the T3SS through a sigma factor cascade, indicating that ppGpp acts as an internal messenger to sense environmental/nutritional stimuli for the regulation of the T3SS and virulence in plant-pathogenic bacteria. Furthermore, the recovery of an
spoT
null mutant, which displayed very unique phenotypes, suggested that small proteins containing a single ppGpp hydrolase domain are functional.
The Escherichia coli Membrane Protein Insertase YidC Assists in the Biogenesis of Penicillin Binding Proteins
Authors: de Sousa Borges Anabela , de Keyzer Jeanine , Driessen Arnold J. M. , Scheffers Dirk-Jan 
Published: February 2015

ABSTRACT

Membrane proteins need to be properly inserted and folded in the membrane in order to perform a range of activities that are essential for the survival of bacteria. The Sec translocon and the YidC insertase are responsible for the insertion of the majority of proteins into the cytoplasmic membrane. YidC can act in combination with the Sec translocon in the insertion and folding of membrane proteins. However, YidC also functions as an insertase independently of the Sec translocon for so-called YidC-only substrates. In addition, YidC can act as a foldase and promote the proper assembly of membrane protein complexes. Here, we investigate the effect of
Escherichia coli
YidC depletion on the assembly of penicillin binding proteins (PBPs), which are involved in cell wall synthesis. YidC depletion does not affect the total amount of the specific cell division PBP3 (FtsI) in the membrane, but the amount of active PBP3, as assessed by substrate binding, is reduced 2-fold. A similar reduction in the amount of active PBP2 was observed, while the levels of active PBP1A/1B and PBP5 were essentially similar. PBP1B and PBP3 disappeared from higher-
M
w
bands upon YidC depletion, indicating that YidC might play a role in PBP complex formation. Taken together, our results suggest that the foldase activity of YidC can extend to the periplasmic domains of membrane proteins.

IMPORTANCE
This study addresses the role of the membrane protein insertase YidC in the biogenesis of penicillin binding proteins (PBPs). PBPs are proteins containing one transmembrane segment and a large periplasmic or extracellular domain, which are involved in peptidoglycan synthesis. We observe that in the absence of YidC, two critical PBPs are not correctly folded even though the total amount of protein in the membrane is not affected. Our findings extend the function of YidC as a foldase for membrane protein (complexes) to periplasmic domains of membrane proteins.
CodY Regulates Expression of the Bacillus subtilis Extracellular Proteases Vpr and Mpr
Authors: Barbieri Giulia , Voigt Birgit , Albrecht Dirk , Hecker Michael , Albertini Alessandra M. , Sonenshein Abraham L. , Ferrari Eugenio , Belitsky Boris R. 
Published: February 2015

ABSTRACT

CodY is a global transcriptional regulator in low-G+C Gram-positive bacteria that is responsive to GTP and branched-chain amino acids. By interacting with its two cofactors, it is able to sense the nutritional and energetic status of the cell and respond by regulating expression of adaptive genetic programs. In
Bacillus subtilis
, more than 200 genes, including those for peptide transporters, intracellular proteolytic enzymes, and amino acid degradative pathways, are controlled by CodY. In this study, we demonstrated that expression of two extracellular proteases, Vpr and Mpr, is negatively controlled by CodY. By gel mobility shift and DNase I footprinting assays, we showed that CodY binds to the regulatory regions of both genes, in the vicinity of their transcription start points. The
mpr
gene is also characterized by the presence of a second, higher-affinity CodY-binding site located at the beginning of its coding sequence. Using strains carrying
vpr
- or
mpr-lacZ
transcriptional fusions in which CodY-binding sites were mutated, we demonstrated that repression of both protease genes is due to the direct effect by CodY and that the
mpr
internal site is required for regulation. The
vpr
promoter is a rare example of a sigma H-dependent promoter that is regulated by CodY. In a
codY
null mutant, Vpr became one of the more abundant proteins of the
B. subtilis
exoproteome.

IMPORTANCE
CodY is a global transcriptional regulator of metabolism and virulence in low-G+C Gram-positive bacteria. In
B. subtilis
, more than 200 genes, including those for peptide transporters, intracellular proteolytic enzymes, and amino acid degradative pathways, are controlled by CodY. However, no role for
B. subtilis
CodY in regulating expression of extracellular proteases has been established to date. In this work, we demonstrate that by binding to the regulatory regions of the corresponding genes,
B. subtilis
CodY negatively controls expression of Vpr and Mpr, two extracellular proteases. Thus, in
B. subtilis
, CodY can now be seen to regulate the entire protein utilization pathway.
Musculoskeletal (MSK) and Sport and Exercise Medicine (SEM) in General Practice (GP): A Novel GP-based MSK and SEM Clinic for Managing Musculoskeletal symptoms in a GP
Authors: Heron Neil 
Published: February 2015

AbstractMusculoskeletal (MSK) complaints are common within primary care (1) (2) (3) but some General Practitioners (GPs)/family physicians do not feel comfortable managing these symptoms (3), preferring to refer onto hospital specialists or Integrated Clinical Assessment and Treatment Services (ICATs). Long waiting times for hospital outpatient reviews are a major cause of patient inconvenience and complaints (4). We therefore aimed to establish a GP-ran MSK and sport and exercise medicine (SEM) clinic based within a Belfast GP surgery that would contribute to a sustainable improvement in managing these common conditions within primary care as well as reducing waiting times for patients with these conditions to see a specialist. This shift from hospital-based to community-based management is in-keeping with recent policy changes within the UK health-system, including Transforming Your Care within Northern Ireland (NI) (5). The GP-ran MSK and SEM clinic was held monthly within a Belfast GP practice, staffed by one GP with a specialist interest in MSK and SEM conditions and its performance was reviewed over a three month period. Parameters audited included cases seen, orthopaedic and x-ray referral rates and secondary care referrals comparing the GP practice’s performance to the same time period in the previous year as well as patient satisfaction questionnaires.
Force protection in contingency operations: an evaluation of temperature monitoring in Sierra Leone
Authors: Cole Catherine , Turnbull C , Eardley W , Hunt P 
Published: February 2015

ObjectivesThe deployment of the UK-led Joint Inter-Agency Taskforce to Sierra Leone in September 2014 brought the era of contingency operations into focus. Daily health screening of such deployed personnel forms a key element of medical force protection. We have performed a service evaluation of an existing screening programme and detail the comparison of the two thermometers used in this role.MethodsData from the existing screening programme were used to inform a sample size required to enable statistically and clinically significant differences to be detected between the two interchangeably used thermometer systems in use. A prospective service evaluation on these devices was then carried out over a 10-day period and the data analysed by parametric tools. 10 personnel had their temperature recorded by both devices at the same time by a single operator every day.ResultsFor the screened population, a mean temperature of 36.55°C and SD of 0.32°C was revealed. Powered to 80% with a two-tailed α of 0.05, the evaluation of the two thermometers revealed no significant difference between recordings taken with either device (p=0.115). The low SD meant that a pyrexial patient (>37.5°C) would require a recording over 3 SD from the population mean.DiscussionEvaluations of medical force protection will carry increasing consequence as the UK deploy on short notice operations to regions of considerable endemic threat. Presence of pyrexia is a key early indicator of illness affecting deployed personnel, and two different thermometer types are provided for this function. We have shown for the first time with statistical and clinical significance that the two thermometers used in contingency force protection are interchangeable. The narrow variance is reassuring and confirms that the chosen trigger (>37.5°C) would warrant further investigation in the pyrexial patient.
Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis
Authors: Harcombe Zoë , Baker Julien S , Cooper Stephen Mark , Davies Bruce , Sculthorpe Nicholas , DiNicolantonio James J , Grace Fergal 
Published: February 2015

ObjectivesNational dietary guidelines were introduced in 1977 and 1983, by the US and UK governments, respectively, with the ambition of reducing coronary heart disease (CHD) by reducing fat intake. To date, no analysis of the evidence base for these recommendations has been undertaken. The present study examines the evidence from randomised controlled trials (RCTs) available to the US and UK regulatory committees at their respective points of implementation.MethodsA systematic review and meta-analysis were undertaken of RCTs, published prior to 1983, which examined the relationship between dietary fat, serum cholesterol and the development of CHD.Results2467 males participated in six dietary trials: five secondary prevention studies and one including healthy participants. There were 370 deaths from all-cause mortality in the intervention and control groups. The risk ratio (RR) from meta-analysis was 0.996 (95% CI 0.865 to 1.147). There were 207 and 216 deaths from CHD in the intervention and control groups, respectively. The RR was 0.989 (95% CI 0.784 to 1.247). There were no differences in all-cause mortality and non-significant differences in CHD mortality, resulting from the dietary interventions. The reductions in mean serum cholesterol levels were significantly higher in the intervention groups; this did not result in significant differences in CHD or all-cause mortality. Government dietary fat recommendations were untested in any trial prior to being introduced.ConclusionsDietary recommendations were introduced for 220 million US and 56 million UK citizens by 1983, in the absence of supporting evidence from RCTs.
Freedom from equine infectious anaemia virus infection in Spanish Purebred horses
Authors: Cruz Fatima , Fores Paloma , Ireland Joanne , Moreno Miguel A. , Newton Richard 
Published: February 2015

IntroductionNo cases of equine infectious anaemia (EIA) have been reported in Spain since 1983. Factors that could increase the risk of reintroducing equine infectious anaemia virus (EIAV) into Spain include the recent occurrence of the disease in Europe and the absence of compulsory serological testing before importation into Spain.Aims and objectivesGiven the importance of the Spanish Purebred (SP) horse breeding industry in Spain, the aim of this cross‐sectional study was to provide evidence of freedom from EIAV in SP stud farms in Central Spain.Materials and methodsSerum samples from 555 SP horses, collected between September 2011 and November 2013, were tested using a commercially available EIAV ELISA with a published sensitivity of 100 per cent.ResultsAll 555 samples were negative for antibody to EIAV, providing evidence of a true EIAV seroprevalence between 0 per cent and 0.53 per cent (95% CIs of the sensitivity and specificity of the ELISA technique used Q10 were 100 per cent and 99.3 per cent, respectively) among the SP breeding population in Central Spain.ConclusionsThese findings should serve to increase confidence when exporting SP horses to other countries.
Long-Term Prognostic Effect of Coronary Atherosclerotic Burden
Authors: Mushtaq Saima , De Araujo Gonçalves Pedro , Garcia-Garcia Hector M. , Pontone Gianluca , Bartorelli Antonio L. , Bertella Erika , Campos Carlos M. , Pepi Mauro , Serruys Patrick W. , Andreini Daniele 
Published: February 2015

Background—
Computed tomography–adapted Leaman score (CT-LeSc) was developed to quantify coronary CT angiography information about atherosclerotic burden (lesion localization, stenosis degree, and plaque composition). The objective of the study is to evaluate CT-LeSc long-term prognostic value in patients with suspected coronary artery disease (CAD).

Methods and Results—
Single-center prospective registry including 1304 consecutive patients undergoing coronary CT angiography for suspected CAD. High CT-LeSc was defined by upper tertile (score, >5) cutoff. Segment involvement score and segment stenosis score were also evaluated. Hard cardiac events (cardiac death and nonfatal acute coronary syndromes) were considered for analysis. Different Cox regression models were used to identify independent event predictors. Kaplan–Meier event-free survival was evaluated in 4 patient subgroups stratified by obstructive (≥50% stenosis) versus nonobstructive CAD and a high (>5) versus a low (≤5) CT-LeSc. Of 1196 patients included in the final analysis (mean follow-up of 52±22 months), 125 patients experienced 136 hard events (18 cardiac deaths and 118 nonfatal myocardial infarction). All atherosclerotic burden scores were independent predictors of cardiac events (hazard ratios of 3.09 for segment involvement score, 4.42 for segment stenosis score, and 5.39 for CT-LeSc). Cumulative event-free survival was 76.8% with a high CT-LeSc and 96.0% with a low CT-LeSc. Event-free survival in nonobstructive CAD with high CT-LeSc (78.6%) was similar to obstructive CAD with high CT-LeSc (76.5%) but lower than obstructive CAD with low CT-LeSc (80.7%).

Conclusions—
CT-LeSc is an independent long-term predictor of hard cardiac events. Patients with nonobstructive CAD and high CT-LeSc had hard event-free survival similar to patients with obstructive CAD.
Statin Use Following Hospitalization Among Medicare Beneficiaries With a Secondary Discharge Diagnosis of Acute Myocardial Infarction
Authors: Yun Huifeng , Safford Monika M. , Brown Todd M. , Farkouh Michael E. , Kent Shia , Sharma Pradeep , Kilgore Meredith , Bittner Vera , Rosenson Robert S. , Delzell Elizabeth , Muntner Paul , Levitan Emily B. 
Published: February 2015

Background

Patients with coronary heart disease are recommended to use statins following hospital discharge. Acute myocardial infarction (
AMI
) is a common complication of hospitalization, but the use of statins following discharge among patients who were not initially hospitalized for
AMI
has not been assessed adequately.

Methods and Results

Using the Medicare 5% national random sample, we determined statin use among beneficiaries who were hospitalized and who had a secondary discharge diagnosis of
AMI
and among beneficiaries who had a primary discharge diagnosis of
AMI
, coronary artery bypass grafting, or percutaneous coronary intervention in 2007–2009. Statin use was defined by a pharmacy (Medicare Part D) claim within 90 days following discharge. Of 8175 Medicare beneficiaries who did not take statins prior to hospitalization, 31.2% with
AMI
as a secondary discharge diagnosis, 60.5% with
AMI
as the primary discharge diagnosis, 67.6% with
coronary artery bypass grafting
, and 63.9% with a
percutaneous coronary intervention
initiated statins. After multivariable adjustment, the risk ratio for statin initiation comparing beneficiaries with a secondary versus primary discharge diagnosis of
AMI
was 0.59 (95%
CI
0.54 to 0.65). Among 5468 Medicare beneficiaries taking statins prior to hospitalization, statin use following discharge was lower for those with
AMI
as a secondary discharge diagnosis (71.8%) compared with their counterparts with
AMI
,
coronary artery bypass grafting
, and
percutaneous coronary intervention
(84.1%, 83.8%, and 87.3%, respectively) as the primary discharge diagnosis.

Conclusion

Medicare beneficiaries with a secondary hospital discharge diagnosis of
AMI
were less likely to fill statins compared with those with other
coronary heart disease
events.
Would Christ Have Become Incarnate Had Adam Not Fallen?
Authors: Lindholm Stefan 
Published: February 2015

In this paper I examine the notion of Christ as Mediator apart from sin in the reformed scholastic theologian, Jerome Zanchi (1516–1590). Calvin developed a rich notion of Christ as Mediator but left an ambiguous heritage to his followers—it led some later interpreters to think of it as imply that the incarnation would have happened apart from sin. In the first part, I lay out some background and positions and in the second I deal with what I argue is a misunderstanding of Zanchi’s use of Christ as Mediator (that it implies incarnation apart from sin). In the third part I will further explore Zanchi’s notion of Christ as Mediator and make comparisons with Thomas Aquinas, John Calvin and Francis Turretin.
A Shear-Based Parameterization of Turbulent Mixing in the Stable Atmospheric Boundary Layer
Authors: Wilson Jordan M. , Venayagamoorthy Subhas K. 
Published: February 2015

AbstractIn this study, shear-based parameterizations of turbulent mixing in the stable atmospheric boundary layer (SABL) are proposed. A relevant length-scale estimate for the mixing length of the turbulent momentum field is constructed from the turbulent kinetic energy and the mean shear rate S as . Using observational data from two field campaigns—the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment and the 1999 Cooperative Atmosphere–Surface Exchange Study (CASES-99)— is shown to have a strong correlation with . The relationship between and corresponds to the ratio of the magnitude of the tangential components of the turbulent momentum flux tensor to , known as stress intensity ratio, . The field data clearly show that is linked to stability. The stress intensity ratio also depends on the flow energetics that can be assessed using a shear-production Reynolds number, , where P is shear production of turbulent kinetic energy and is the kinematic viscosity. This analysis shows that high mixing rates can indeed persist at strong stability. On this basis, shear-based parameterizations are proposed for the eddy diffusivity for momentum, , and eddy diffusivity for heat, , showing remarkable agreement with the exact quantities. Furthermore, a broader assessment of the proposed parameterizations is given through an a priori evaluation of large-eddy simulation (LES) data from the first GEWEX Atmospheric Boundary Layer Study (GABLS). The shear-based parameterizations outperform many existing models in predicting turbulent mixing in the SABL. The results of this study provide a framework for improved representation of the SABL in operational models.