bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subdomain 2 of the Autotransporter Pet Is the Ligand Site for Recognizing the Pet Receptor on the Epithelial Cell Surface
Authors: Chavez-Dueñas Lucia , Serapio-Palacios Antonio , Nava-Acosta Raul , Navarro-Garcia Fernando 
Published: April 2016

ABSTRACT
Most autotransporter passenger domains, regardless of their diversity in function, fold or are predicted to fold as right-handed β-helices carrying various loops that are presumed to confer functionality. Our goal here was to identify the subdomain (loop) or amino acid sequence of the Pet passenger domain involved in the receptor binding site on the host cell for Pet endocytosis. Here, we show that d1 and d2 subdomains, as well as the amino acid sequence linking the subdomain d2 and the adjacent β-helix (PDWET), are not required for Pet secretion through the autotransporter system and that none of our deletion mutants altered the predicted long right-handed β-helical structure. Interestingly, Pet lacking the d2 domain (PetΔd2) was unable to bind on the epithelial cell surface, in contrast to Pet lacking d1 (PetΔd1) subdomain or PDWET sequences. Moreover, the purified d1 subdomain, the biggest subdomain (29.8 kDa) containing the serine protease domain, was also unable to bind the cell surface. Thus, d2 sequence (54 residues without the PDWET sequence) was required for Pet binding to eukaryotic cells. In addition, this d2 sequence was also needed for Pet internalization but not for inducing cell damage. In contrast, PetΔd1, which was able to bind and internalize inside the cell, was unable to cause cell damage. Furthermore, unlike Pet, PetΔd2 was unable to bind cytokeratin 8, a Pet receptor. These data indicate that the surface d2 subdomain is essential for the ligand-receptor (Pet-Ck8) interaction for Pet uptake and to start the epithelial cell damage by this toxin.
Early-Life Intranasal Colonization with Nontypeable Haemophilus influenzae Exacerbates Juvenile Airway Disease in Mice
Authors: McCann Jessica R. , Mason Stanley N. , Auten Richard L. , St. Geme Joseph W. , Seed Patrick C. 
Published: April 2016

ABSTRACT

Accumulating evidence suggests a connection between asthma development and colonization with nontypeable
Haemophilus influenzae
(NTHi). Specifically, nasopharyngeal colonization of human infants with NTHi within 4 weeks of birth is associated with an increased risk of asthma development later in childhood. Monocytes derived from these infants have aberrant inflammatory responses to common upper respiratory bacterial antigens compared to those of cells derived from infants who were not colonized and do not go on to develop asthma symptoms in childhood. In this study, we hypothesized that early-life colonization with NTHi promotes immune system reprogramming and the development of atypical inflammatory responses. To address this hypothesis in a highly controlled model, we tested whether colonization of mice with NTHi on day of life 3 induced or exacerbated juvenile airway disease using an ovalbumin (OVA) allergy model of asthma. We found that animals that were colonized on day of life 3 and subjected to induction of allergy had exacerbated airway disease as juveniles, in which exacerbated airway disease was defined as increased cellular infiltration into the lung, increased amounts of inflammatory cytokines interleukin-5 (IL-5) and IL-13 in lung lavage fluid, decreased regulatory T cell-associated
FOXP3
gene expression, and increased mucus production. We also found that colonization with NTHi amplified airway resistance in response to increasing doses of a bronchoconstrictor following OVA immunization and challenge. Together, the murine model provides evidence for early-life immune programming that precedes the development of juvenile airway disease and corroborates observations that have been made in human children.
The Treponema denticola FhbB Protein Is a Dominant Early Antigen That Elicits FhbB Variant-Specific Antibodies That Block Factor H Binding and Cleavage by Dentilisin
Authors: Miller Daniel P. , Oliver Lee D. , Tegels Brittney K. , Reed Lucas A. , O'Bier Nathaniel S. , Kurniyati Kurni , Faust Lindsay A. , Lawson Christine K. , Allard Anna M. , Caimano Melissa J. , Marconi Richard T. 
Published: April 2016

ABSTRACT

The
Treponema denticola
FhbB protein contributes to immune evasion by binding factor H (FH). Cleavage of FH by the
T. denticola
protease, dentilisin, may contribute to the local immune dysregulation that is characteristic of periodontal disease (PD). Although three FhbB phyletic types have been defined (FhbB1, FhbB2, and FhbB3), the
in vivo
expression patterns and antigenic heterogeneity of FhbB have not been assessed. Here, we demonstrate that FhbB is a dominant early antigen that elicits FhbB type-specific antibody (Ab) responses. Using the murine skin abscess model, we demonstrate that the presence or absence of FhbB or dentilisin significantly influences Ab responses to infection and skin abscess formation. Competitive binding analyses revealed that α-FhbB Ab can compete with FH for binding to
T. denticola
and block dentilisin-mediated FH cleavage. Lastly, we demonstrate that dentilisin cleavage sites reside within critical functional domains of FH, including the complement regulatory domain formed by CCPs 1 to 4. Analysis of the FH cleavage products revealed that they lack cofactor activity. The data presented here provide insight into the
in vivo
significance of dentilisin, FhbB and its antigenic diversity, and the potential impact of FH cleavage on the regulation of complement activation.
CTL0511 from Chlamydia trachomatis Is a Type 2C Protein Phosphatase with Broad Substrate Specificity
Authors: Claywell Ja E. , Fisher Derek J. 
Published: April 2016

ABSTRACT

Protein phosphorylation has become increasingly recognized for its role in regulating bacterial physiology and virulence.
Chlamydia
spp. encode two validated Hanks'-type Ser/Thr protein kinases, which typically function with cognate protein phosphatases and appear capable of global protein phosphorylation. Consequently, we sought to identify a Ser/Thr protein phosphatase partner for the chlamydial kinases. CTL0511 from
Chlamydia trachomatis
L2 434/Bu, which has homologs in all sequenced
Chlamydia
spp., is a predicted type 2C Ser/Thr protein phosphatase (PP2C). Recombinant maltose-binding protein (MBP)-tagged CTL0511 (rCTL0511) hydrolyzed
p
-nitrophenyl phosphate (pNPP), a generic phosphatase substrate, in a MnCl
2
-dependent manner at physiological pH. Assays using phosphopeptide substrates revealed that rCTL0511 can dephosphorylate phosphorylated serine (P-Ser), P-Thr, and P-Tyr residues using either MnCl
2
or MgCl
2
, indicating that metal usage can alter substrate preference. Phosphatase activity was unaffected by PP1, PP2A, and PP3 phosphatase inhibitors, while mutation of conserved PP2C residues significantly inhibited activity. Finally, phosphatase activity was detected in elementary body (EB) and reticulate body (RB) lysates, supporting a role for protein dephosphorylation in chlamydial development. These findings support that CTL0511 is a metal-dependent protein phosphatase with broad substrate specificity, substantiating a reversible phosphorylation network in
C. trachomatis
.

IMPORTANCE
Chlamydia
spp. are obligate intracellular bacterial pathogens responsible for a variety of diseases in humans and economically important animal species. Our work demonstrates that
Chlamydia
spp. produce a PP2C capable of dephosphorylating P-Thr, P-Ser, and P-Tyr and that
Chlamydia trachomatis
EBs and RBs possess phosphatase activity. In conjunction with the chlamydial Hanks'-type kinases Pkn1 and PknD, validation of CTL0511 fulfills the enzymatic requirements for a reversible phosphoprotein network. As protein phosphorylation regulates important cellular processes, including metabolism, differentiation, and virulence, in other bacterial pathogens, these results set the stage for elucidating the role of global protein phosphorylation in chlamydial physiology and virulence.
PilZ Domain Protein FlgZ Mediates Cyclic Di-GMP-Dependent Swarming Motility Control in Pseudomonas aeruginosa
Authors: Baker Amy E. , Diepold Andreas , Kuchma Sherry L. , Scott Jessie E. , Ha Dae Gon , Orazi Giulia , Armitage Judith P. , O'Toole George A. 
Published: April 2016

ABSTRACT

The second messenger cyclic diguanylate (c-di-GMP) is an important regulator of motility in many bacterial species. In
Pseudomonas aeruginosa
, elevated levels of c-di-GMP promote biofilm formation and repress flagellum-driven swarming motility. The rotation of
P. aeruginosa
's polar flagellum is controlled by two distinct stator complexes, MotAB, which cannot support swarming motility, and MotCD, which promotes swarming motility. Here we show that when c-di-GMP levels are elevated, swarming motility is repressed by the PilZ domain-containing protein FlgZ and by Pel polysaccharide production. We demonstrate that FlgZ interacts specifically with the motility-promoting stator protein MotC in a c-di-GMP-dependent manner and that a functional green fluorescent protein (GFP)-FlgZ fusion protein shows significantly reduced polar localization in a strain lacking the MotCD stator. Our results establish FlgZ as a c-di-GMP receptor affecting swarming motility by
P. aeruginosa
and support a model wherein c-di-GMP-bound FlgZ impedes motility via its interaction with the MotCD stator.

IMPORTANCE
The regulation of surface-associated motility plays an important role in bacterial surface colonization and biofilm formation. c-di-GMP signaling is a widespread means of controlling bacterial motility, and yet the mechanism whereby this signal controls surface-associated motility in
P. aeruginosa
remains poorly understood. Here we identify a PilZ domain-containing c-di-GMP effector protein that contributes to c-di-GMP-mediated repression of swarming motility by
P. aeruginosa
. We provide evidence that this effector, FlgZ, impacts swarming motility via its interactions with flagellar stator protein MotC. Thus, we propose a new mechanism for c-di-GMP-mediated regulation of motility for a bacterium with two flagellar stator sets, increasing our understanding of surface-associated behaviors, a key prerequisite to identifying ways to control the formation of biofilm communities.
Modulation of the Lytic Activity of the Dedicated Autolysin for Flagellum Formation SltF by Flagellar Rod Proteins FlgB and FlgF
Authors: Herlihey Francesca A. , Osorio-Valeriano Manuel , Dreyfus Georges , Clarke Anthony J. 
Published: April 2016

ABSTRACT

SltF was identified previously as an autolysin required for the assembly of flagella in the alphaproteobacteria, but the nature of its peptidoglycan lytic activity remained unknown. Sequence alignment analyses suggest that it could function as either a muramidase, lytic transglycosylase, or β-
N
-acetylglucosaminidase. Recombinant SltF from
Rhodobacter sphaeroides
was purified to apparent homogeneity, and it was demonstrated to function as a lytic transglycosylase based on enzymatic assays involving mass spectrometric analyses. Circular dichroism (CD) analysis determined that it is composed of 83.4% α-structure and 1.48% β-structure and thus is similar to family 1A lytic transglycosylases. However, alignment of apparent SltF homologs identified in the genome database defined a new subfamily of the family 1 lytic transglycosylases. SltF was demonstrated to be endo-acting, cleaving within chains of peptidoglycan, with optimal activity at pH 7.0. Its activity is modulated by two flagellar rod proteins, FlgB and FlgF: FlgB both stabilizes and stimulates SltF activity, while FlgF inhibits it. Invariant Glu57 was confirmed as the sole catalytic acid/base residue of SltF.

IMPORTANCE
The bacterial flagellum is comprised of a basal body, hook, and helical filament, which are connected by a rod structure. With a diameter of approximately 4 nm, the rod is larger than the estimated pore size within the peptidoglycan sacculus, and hence its insertion requires the localized and controlled lysis of this essential cell wall component. In many beta- and gammaproteobacteria, this lysis is catalyzed by the β-
N
-acetylglucosaminidase domain of FlgJ. However, FlgJ of the alphaproteobacteria lacks this activity and instead it recruits a separate enzyme, SltF, for this purpose. In this study, we demonstrate that SltF functions as a newly identified class of lytic transglycosylases and that its autolytic activity is uniquely modulated by two rod proteins, FlgB and FlgF.
Influence of age on the prevalence and components of the metabolic syndrome and the association with cardiovascular disease
Authors: Devers Marion C , Campbell Stewart , Simmons David 
Published: April 2016

ObjectiveThe significance of the metabolic syndrome (MS) is debated. We investigated whether MS component (by ATPIII and IDF definitions) clustering and any association between MS and prevalent cardiovascular disease (CVD) varied with age.Research design and methodsIn all, 1429 adults (≥25 years) from randomly selected households in rural Victoria, Australia, were assessed for components of MS and prevalent CVD. The expected prevalence of MS was calculated following a simple probabilistic model using the prevalence of each MS component.ResultsThe observed prevalence of MS was greater than expected: 27.0% vs 21.2% (ATPIII) and 36.0% vs 30.1% (IDF; p<0.0001), based on the prevalence of individual components. There was significant clustering of 4 and 5 MS components in participants <65 years (p<0.0001). CVD was more prevalent in MS participants, 13.5% (IDF), 14.5% (ATPIII) versus 5.3% (no MS) p<0.0001. The OR for CVD in MS participants was greatest in those <45 years OR (95% CI): IDF 17.5 (1.8 to 172); ATPIII 24.3(2.4 to 241), p<0.001 for both, and was not significant in those >65 years. The prevalence of MS (ATPIII) with normal waist circumference (WC) was less than expected (4.8% vs 7.9%, p<0.002). Low levels of high-density lipoprotein and high triglyceride were less common in older MS participants.ConclusionsATPIII MS is rare among those with a normal WC. MS components cluster most markedly among those aged <65 years, who also experience substantially greater rates of CVD. Younger patients with MS may warrant more aggressive CVD preventative treatment than suggested by the summation of their individual risk factors.
Qualitative study exploring surgical team members' perception of patient safety in conflict-ridden Eastern Democratic Republic of Congo
Authors: Labat Francoise , Sharma Anjali 
Published: April 2016

ObjectiveTo identify potential barriers to patient safety (PS) interventions from the perspective of surgical team members working in an operating theatre in Eastern Democratic Republic of Congo (DRC).DesignIn-depth interviews were conducted and analysed using qualitative content analysis.SettingGovernmental referral teaching hospital in Eastern DRC.ParticipantsWe purposively selected 2–4 national and expatriate surgical team members from each specialisation. Of the 31 eligible surgical health workers (HWs), 17 volunteered to be interviewed.ResultsEconomics issues affected PS throughout the entire health system, from human resources and hospital management, to access to healthcare for patients. Surgical team members seemed embedded in a paternalistic organisational structure and blame culture accompanied by perceived inefficient support services and low salaries. The armed conflict did not only worsen these system failures, it also carried direct threats to patients and HWs, and resulted in complex indirect consequences compromising PS. The increased corruption within health organisations, and population impoverishment and substance abuse among health staff adversely altered safe care. Simultaneously, HWs’ reported resilience and resourcefulness to address barrier to PS. Participants had varying views on external aid depending on its relevance.ConclusionsThe complex links between war and PS emphasise the importance of a comprehensive approach including occupational health to strengthen HWs' resilience, external clinical audits to limit corruption, and educational programmes in PS to support patient-centred care and address blame culture. Finally, improvement of equity in the health financing system seems essential to ensure access to healthcare and safe perioperative outcomes for all.
Is poor self-rated health associated with low-grade inflammation in 43 110 late adolescent men of the general population? A cross-sectional study
Authors: Warnoff Carin , Lekander Mats , Hemmingsson Tomas , Sorjonen Kimmo , Melin Bo , Andreasson Anna 
Published: April 2016

ObjectiveSelf-rated health is a powerful predictor of long-term health and mortality, hence the importance of a better understanding of its biological determinants. Previous studies have shown that low-grade inflammation is associated with poor self-rated health in clinical and healthy populations, but the evidence is sparse in men and completely lacking for men in late adolescence. The aim of this study was to investigate the association between low-grade inflammation and self-rated health among conscripts. It was hypothesised that high levels of inflammatory factors would be associated with poor self-rated health.DesignData from 49 321 men (18–21 years) conscripted for military service in 1969 and 1970 were used. Inflammation had been measured through erythrocyte sedimentation rate (ESR). Self-rated health had been assessed on a five-point scale, and was dichotomised into Good (‘Very good’/‘Good’/‘Fair’) versus Poor (‘Poor’/‘Very poor’). Data from 43 110 conscripts with normal levels of ESR, and who reported self-rated health remained after exclusion of those with ESR <1 and >11 mm/h. Associations were calculated using logistic regression analyses. Adjustments were made for body mass index, socioeconomic position, inflammatory disease, emotion regulation, smoking, risky use of alcohol and physical activity.ResultsHigh levels of ESR were associated with higher odds for poor self-rated health (OR: 1.077 for each unit mm/h increase in ESR, 95% CI 1.049 to 1.105).ConclusionsThe present study shows for the first time a significant association between a marker of inflammation and self-rated health in late adolescent men, adding to evidence of an association between low-grade inflammation and subjective health perception also in men, as previously demonstrated in women. Further support for inflammation as part of a general psychobiological process that underpins subjective health perception is hereby provided.
Has there been a change in the rates of UK sickness certification for back pain over time? An examination of historical data from 2000 to 2010
Authors: Wynne-Jones Gwenllian , Dunn Kate M 
Published: April 2016

ObjectivesThis paper aims to investigate historical patterns of sickness certification for back pain from 2000 to 2010.DesignElectronic medical records from 14 practices that are part of the National Institute for Health Research (NIHR) Clinical Research Network: West Midlands were reviewed. All records for back pain consultations from 2000 to 2010 were downloaded and matched, by date, to corresponding sickness certification records.SettingPrimary Care.ResultsA total of 93 896 back pain consultations were recorded over the 11-year period, resulting in 30 913 sickness certificates. There was a statistically significant decrease in the rate of certification over the period, falling from 376.8 (95% CI 362.1 to 392) per 1000 back pain consultations in 2000 to 246.5 (95% CI 236.5 to 332.9) per 1000 back pain consultations in 2010. There was also a statistically significant difference in certification between males and females, with males issued more certificates than females. There was a statistically significant difference in certification by age, with those aged 60 years and over being less likely to be issued a certificate compared to all other age groups.ConclusionsRates of sickness certification for back pain demonstrated a downward trend between 2000 and 2010. While the reasons for this are not transparent, it may be related to changing beliefs around working with back pain.
Clinical validation of hrHPV testing on vaginal and urine self-samples in primary cervical screening (cross-sectional results from the Papillomavirus Dumfries and Galloway—PaVDaG study)
Authors: Stanczuk Grazyna , Baxter Gwendoline , Currie Heather , Lawrence James , Cuschieri Kate , Wilson Allan , Arbyn Marc 
Published: April 2016

ObjectivesPapillomavirus Dumfries and Galloway (PaVDaG) assessed the performance of a high-risk human papillomavirus (hrHPV) PCR-based assay to detect high-grade cervical intraepithelial neoplasia (CIN2+) in self-collected vaginal and urine samples.SettingWomen attending routine cervical screening in primary care.Participants5318 women aged 20–60 years provided self-collected random urine and vaginal samples for hrHPV testing and a clinician-collected liquid-based cytology (LBC) sample for cytology and hrHPV testing.InterventionsHrHPV testing. All samples were tested for hrHPV using the PCR-based cobas 4800 assay. Colposcopy was offered to women with high-grade or repeated borderline/low-grade cytological abnormalities; also to those who were LBC negative but hrHPV 16/18 positive.Primary and secondary outcome measuresThe self-tests' absolute sensitivity and specificity for CIN2+ were assessed on all biospecimens; also, their relative sensitivity and specificity compared with clinician-taken samples. Interlaboratory and intralaboratory performance of the hrHPV assay in self-collected samples was also established.ResultsHrHPV prevalence was 14.7%, 16.6% and 11.6% in cervical, vaginal and urine samples, respectively. Sensitivity for detecting CIN2+ was 97.7% (95% to 100%), 94.6% (90.7% to 98.5%) and 63.1% (54.6% to 71.7%) for cervical, vaginal and urine hrHPV detection, respectively. The corresponding specificities were 87.3% (86.4% to 88.2%), 85.4% (84.4% to 86.3%) and 89.8% (89.0% to 90.7%). There was a 38% (24% to 57%) higher HPV detection rate in vaginal self-samples from women over 50 years compared with those ≤29 years. Relative sensitivity and specificity of hrHPV positivity for the detection of CIN2+ in vaginal versus cervical samples were 0.97 (0.94 to 1.00) and 0.98 (0.97 to 0.99); urine versus cervical comparisons were 0.53 (0.42 to 0.67) and 1.03 (1.02 to 1.04). The intralaboratory and interlaboratory agreement for hrHPV positivity in self-samples was high (κ values 0.98 (0.96 to 0.99) and 0.94 (0.92 to 0.97) for vaginal samples and 0.95 (0.93 to 0.98) and 0.90 (0.87 to 0.94) for urine samples).ConclusionsThe sensitivity of self-collected vaginal samples for the detection of CIN2+ was similar to that of cervical samples and justifies consideration of this sample for primary screening.