bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the Role of the
opgGH
Operon in Yersinia pseudotuberculosis and Its Deletion during the Emergence of Yersinia pestis
Authors: Quintard Kévin , Dewitte Amélie , Reboul Angéline , Madec Edwige , Bontemps-Gallo Sébastien , Dondeyne Jacqueline , Marceau Michaël , Simonet Michel , Lacroix Jean-Marie , Sebbane Florent 
Published: July 2015

ABSTRACT

The
opgGH
operon encodes glucosyltransferases that synthesize osmoregulated periplasmic glucans (OPGs) from UDP-glucose, using acyl carrier protein (ACP) as a cofactor. OPGs are required for motility, biofilm formation, and virulence in various bacteria. OpgH also sequesters FtsZ in order to regulate cell size according to nutrient availability.
Yersinia pestis
(the agent of flea-borne plague) lost the
opgGH
operon during its emergence from the enteropathogen
Yersinia pseudotuberculosis
. When expressed in OPG-negative strains of
Escherichia coli
and
Dickeya dadantii
,
opgGH
from
Y. pseudotuberculosis
restored OPGs synthesis, motility, and virulence. However,
Y. pseudotuberculosis
did not produce OPGs (i) under various growth conditions or (ii) when overexpressing its
opgGH
operon, its
galUF
operon (governing UDP-glucose), or the
opgGH
operon or Acp from
E. coli
. A Δ
opgGH
Y. pseudotuberculosis
strain showed normal motility, biofilm formation, resistance to polymyxin and macrophages, and virulence but was smaller. Consistently,
Y. pestis
was smaller than
Y. pseudotuberculosis
when cultured at ≥37°C, except when the plague bacillus expressed
opgGH
.
Y. pestis
expressing
opgGH
grew normally in serum and within macrophages and was fully virulent in mice, suggesting that small cell size was not advantageous in the mammalian host. Lastly,
Y. pestis
expressing
opgGH
was able to infect
Xenopsylla cheopis
fleas normally. Our results suggest an evolutionary scenario whereby an ancestral
Yersinia
strain lost a factor required for OPG biosynthesis but kept
opgGH
(to regulate cell size). The
opgGH
operon was presumably then lost because OpgH-dependent cell size control became unnecessary.
Borrelia burgdorferi RevA Significantly Affects Pathogenicity and Host Response in the Mouse Model of Lyme Disease
Authors: Byram Rebecca , Gaultney Robert A. , Floden Angela M. , Hellekson Christopher , Stone Brandee L. , Bowman Amy , Stevenson Brian , Johnson Barbara J. B. , Brissette Catherine A. 
Published: July 2015

ABSTRACT

The Lyme disease spirochete,
Borrelia burgdorferi
, expresses RevA and numerous outer surface lipoproteins during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA is poised to interact with the extracellular matrix of the host. To further define the role(s) of RevA during mammalian infection, we created a mutant that is unable to produce RevA. The mutant was still infectious to mice, although it was significantly less well able to infect cardiac tissues. Complementation of the mutant with a wild-type
revA
gene restored heart infectivity to wild-type levels. Additionally,
revA
mutants led to increased evidence of arthritis, with increased fibrotic collagen deposition in tibiotarsal joints. The mutants also induced increased levels of the chemokine CCL2, a monocyte chemoattractant, in serum, and this increase was abolished in the complemented strain. Therefore, while
revA
is not absolutely essential for infection, deletion of
revA
had distinct effects on dissemination, arthritis severity, and host response.
Ferric Uptake Regulator Fur Control of Putative Iron Acquisition Systems in Clostridium difficile
Authors: Ho Theresa D. , Ellermeier Craig D. 
Published: July 2015

ABSTRACT

Clostridium difficile
is an anaerobic, Gram-positive, spore-forming opportunistic pathogen and is the most common cause of hospital-acquired infectious diarrhea. Although iron acquisition in the host is a key to survival of bacterial pathogens, high levels of intracellular iron can increase oxidative damage. Therefore, expression of iron acquisition mechanisms is tightly controlled by transcriptional regulators. We identified a
C. difficile
homologue of the master bacterial iron regulator Fur. Using targetron mutagenesis, we generated a
fur
insertion mutant of
C. difficile
. To identify the genes regulated by Fur in
C. difficile
, we used microarray analysis to compare transcriptional differences between the
fur
mutant and the wild type when grown in high-iron medium. The
fur
mutant had increased expression of greater than 70 transcriptional units. Using quantitative reverse transcriptase PCR (qRT-PCR), we analyzed several of the Fur-regulated genes identified by the microarray and verified that they are both iron and Fur regulated in
C. difficile
. Among those Fur- and iron-repressed genes were
C. difficile
genes encoding 7 putative cation transport systems of different classes. We found that Fur was able to bind the DNA upstream of three Fur-repressed genes in electrophoretic mobility shift assays. We also demonstrate that expression of Fur-regulated putative iron acquisition systems was increased during
C. difficile
infection using the hamster model. Our data suggest that
C. difficile
expresses multiple iron transport mechanisms in response iron depletion
in vitro
and
in vivo
.

IMPORTANCE
Clostridium difficile
is the most common cause of hospital-acquired infectious diarrhea and has been recently classified as an “urgent” antibiotic resistance threat by the CDC. To survive and cause disease, most bacterial pathogens must acquire the essential enzymatic cofactor iron. While import of adequate iron is essential for most bacterial growth, excess intracellular iron can lead to extensive oxidative damage. Thus, bacteria must regulate iron import to maintain iron homeostasis. We demonstrate here that
C. difficile
regulates expression of several putative iron acquisition systems using the transcriptional regulator Fur. These import mechanisms are induced under iron-limiting conditions
in vitro
and during
C. difficile
infection of the host. This suggests that during a
C. difficile
infection, iron availability is limited
in vivo
.
DNA-Binding Protein HU Coordinates Pathogenicity in Vibrio parahaemolyticus
Authors: Phan Ngoc Quang , Uebanso Takashi , Shimohata Takaaki , Nakahashi Mutsumi , Mawatari Kazuaki , Takahashi Akira 
Published: July 2015

ABSTRACT

HU is one of the most abundant nucleoid-associated proteins in bacterial cells and regulates the expression of many genes involved in growth, motility, metabolism, and virulence. It is known that
Vibrio parahaemolyticus
pathogenicity is related to its characteristic rapid growth and that type III secretion system 1 (T3SS1) contributes to its cytotoxicity. However, it is not known if HU plays a role in the pathogenicity of
V. parahaemolyticus
. In the present study, we investigated the effect of HU proteins HU-2 (HUα) (
V. parahaemolyticus
2911 [vp2911]) and HUβ (vp0920) on the pathogenicity of
V. parahaemolyticus
. We found that a deletion of both HU subunits (yielding the ΔHUs [Δ
vp0920
Δ
vp2911
] strain), but not single deletions, led to a reduction of the growth rate. In addition, expression levels of T3SS1-related genes, including
exsA
(positive regulator),
exsD
(negative regulator),
vp1680
(cytotoxic effector), and
vp1671
(T3SS1 apparatus), were reduced in the ΔHUs strain compared to the wild type (WT). As a result, cytotoxicity to HeLa cells was decreased in the ΔHUs strain. The additional deletion of
exsD
in the ΔHUs strain restored T3SS1-related gene expression levels and cytotoxicity but not the growth rate. These results suggest that the HU protein regulates the levels of T3SS1 gene expression and cytotoxicity in a growth rate-independent manner.

IMPORTANCE
Nucleoid-binding protein HU regulates cellular behaviors, including nucleoid structuring, general recombination, transposition, growth, replication, motility, metabolism, and virulence. It is thought that both the number of bacteria and the number of virulence factors may affect the pathogenicity of bacteria. In the present study, we investigated which factor(s) has a dominant role during infection in one of the most rapidly growing bacterial species,
Vibrio parahaemolyticus
. We found that
V. parahaemolyticus
cytotoxicity is regulated, in a growth rate-independent manner, by the HU proteins through regulation of a number of virulence factors, including T3SS1 gene expression.
Energy Conservation Associated with Ethanol Formation from H
2
and CO
2
in Clostridium autoethanogenum Involving Electron Bifurcation
Authors: Mock Johanna , Zheng Yanning , Mueller Alexander P. , Ly San , Tran Loan , Segovia Simon , Nagaraju Shilpa , Köpke Michael , Dürre Peter , Thauer Rudolf K. 
Published: July 2015

ABSTRACT

Most acetogens can reduce CO
2
with H
2
to acetic acid via the Wood-Ljungdahl pathway, in which the ATP required for formate activation is regenerated in the acetate kinase reaction. However, a few acetogens, such as
Clostridium autoethanogenum
,
Clostridium ljungdahlii
, and
Clostridium ragsdalei
, also form large amounts of ethanol from CO
2
and H
2
. How these anaerobes with a growth pH optimum near 5 conserve energy has remained elusive. We investigated this question by determining the specific activities and cofactor specificities of all relevant oxidoreductases in cell extracts of H
2
/CO
2
-grown
C. autoethanogenum
. The activity studies were backed up by transcriptional and mutational analyses. Most notably, despite the presence of six hydrogenase systems of various types encoded in the genome, the cells appear to contain only one active hydrogenase. The active [FeFe]-hydrogenase is electron bifurcating, with ferredoxin and NADP as the two electron acceptors. Consistently, most of the other active oxidoreductases rely on either reduced ferredoxin and/or NADPH as the electron donor. An exception is ethanol dehydrogenase, which was found to be NAD specific. Methylenetetrahydrofolate reductase activity could only be demonstrated with artificial electron donors. Key to the understanding of this energy metabolism is the presence of membrane-associated reduced ferredoxin:NAD
+
oxidoreductase (Rnf), of electron-bifurcating and ferredoxin-dependent transhydrogenase (Nfn), and of acetaldehyde:ferredoxin oxidoreductase, which is present with very high specific activities in H
2
/CO
2
-grown cells. Based on these findings and on thermodynamic considerations, we propose metabolic schemes that allow, depending on the H
2
partial pressure, the chemiosmotic synthesis of 0.14 to 1.5 mol ATP per mol ethanol synthesized from CO
2
and H
2
.

IMPORTANCE
Ethanol formation from syngas (H
2
, CO, and CO
2
) and from H
2
and CO
2
that is catalyzed by bacteria is presently a much-discussed process for sustainable production of biofuels. Although the process is already in use, its biochemistry is only incompletely understood. The most pertinent question is how the bacteria conserve energy for growth during ethanol formation from H
2
and CO
2
, considering that acetyl coenzyme A (acetyl-CoA), is an intermediate. Can reduction of the activated acetic acid to ethanol with H
2
be coupled with the phosphorylation of ADP? Evidence is presented that this is indeed possible, via both substrate-level phosphorylation and electron transport phosphorylation. In the case of substrate-level phosphorylation, acetyl-CoA reduction to ethanol proceeds via free acetic acid involving acetaldehyde:ferredoxin oxidoreductase (carboxylate reductase).
A systematic review of the predictors of health service utilisation by adults with mental disorders in the UK
Authors: Twomey Conal D , Baldwin David S , Hopfe Maren , Cieza Alarcos 
Published: July 2015

ObjectivesTo identify variables that predict health service utilisation (HSU) by adults with mental disorders in the UK, and to determine the evidence level for these predictors.DesignA narrative synthesis of peer-reviewed studies published after the year 2000. The search was conducted using four databases (ie,PsycINFO, CINAHL Plus with full text, MEDLINEandEMBASE) and completed on 25 March 2014.SettingThe majority of included studies were set in health services across primary, secondary, specialist and inpatient care. Some studies used data from household and postal surveys.ParticipantsIncluded were UK-based studies that predicted HSU by adults with mental disorders. Participants had a range of mental disorders including psychotic disorders, personality disorders, depression, anxiety disorders, eating disorders and dementia.Primary outcomeA wide range of HSU outcomes were examined, including general practitioner (GP) contacts, medication usage, psychiatrist contacts, psychotherapy attendances, inpatient days, accident and emergency admissions and ‘total HSU’.ResultsTaking into account study quality, 28 studies identified a range of variables with good preliminary evidence supporting their ability to predict HSU. Of these variables, comorbidity, personality disorder, age (heterogeneous age ranges), neurotic symptoms, female gender, a marital status of divorced, separated or widowed, non-white ethnicity, high previous HSU and activities of daily living, were associated with increased HSU. Moreover, good preliminary evidence was found for associations of accessing a primary care psychological treatment service and medication use with decreased HSU.ConclusionsThe findings can inform decisions about which variables might be used to derive mental health clusters in ‘payment by results’ systems in the UK. The findings also support the need to investigate whether combining broad diagnoses with care pathways is an effective method for mental health clustering, and the need for research to further examine the association between mental health clusters and HSU.
How family carers engage with technical health procedures in the home: a grounded theory study
Authors: McDonald Janet , McKinlay Eileen , Keeling Sally , Levack William 
Published: July 2015

ObjectivesTo explore the experiences of family carers who manage technical health procedures at home and describe their learning process.DesignA qualitative study using grounded theory.ParticipantsNew Zealand family carers (21 women, 5 men) who managed technical health procedures such as enteral feeding, peritoneal dialysis, tracheostomy care, a central venous line or urinary catheter. In addition, 15 health professionals involved in teaching carers were interviewed.MethodsSemistructured interviews were coded soon after completion and preliminary analysis influenced subsequent interviews. Additional data were compared with existing material and as analysis proceeded, initial codes were grouped into higher order concepts until a core concept was described. Interviewing continued until no new ideas emerged and concepts were well defined.ResultsThe response of carers to the role of managing technical health procedures in the home is presented in terms of five dispositions: (1) Embracing care, (2) Resisting, (3) Reluctant acceptance, (4) Relinquishing and (5) Being overwhelmed. These dispositions were not static and carers commonly changed between them. Embracing care included cognitive understanding of the purpose and benefits of a procedure; accepting a ‘technical’ solution; practical management; and an emotional response. Accepting embrace is primarily motivated by perceived benefits for the recipient. It may also be driven by a lack of alternatives. Resisting or reluctant acceptance results from a lack of understanding about the procedure or willingness to manage it. Carers need adequate support to avoid becoming overwhelmed, and there are times when it is appropriate to encourage them to relinquish care for the sake of their own needs.ConclusionsThe concept of embracing care encourages health professionals to extend their attention beyond simply the practical aspects of technical procedures to assessing and addressing carers’ emotional and behavioural responses to health technology during the training process.
Women's interpretation of and responses to potential gynaecological cancer symptoms: a qualitative interview study
Authors: Low E L , Whitaker K L , Simon A E , Sekhon M , Waller J 
Published: July 2015

ObjectiveTo explore women's experiences of symptoms potentially indicative of gynaecological cancer in a community-based sample without imposing a cancer perspective.DesignA qualitative interview study with thematic analysis of transcripts.Participants26 women aged ≥30 years, who had experienced a symptom that might indicate gynaecological cancer in the past 3 months, were recruited using a screening questionnaire distributed online and in community settings.SettingLondon, UK.ResultsWomen attributed gynaecological symptoms to existing illnesses/conditions or considered themselves to be predisposed to them, either through their ‘genes’ or previous personal experience. Normalising symptoms by attributing them to demographic characteristics (eg, age, sex) was common, as was considering them a side effect of hormonal contraception. When women raised cancer as a possible cause, they often dismissed it as unlikely. Responses to symptoms included self-management (eg, self-medicating, making lifestyle changes), adopting a ‘lay system of care’, or consulting a healthcare professional. Triggers to help-seeking included persistent, painful or debilitating symptoms, concern about symptom seriousness, and feeling that help-seeking was legitimised. Barriers to help-seeking included lack of concern, vague symptoms, unusual symptom location, competing time demands, previous negative experiences with the healthcare system, and not wanting to be perceived as a time-waster.ConclusionsAttributions of symptoms potentially indicative of a gynaecological cancer were varied, but most often involved women fitting symptoms into their expectations of what was ‘normal’. Normalising acted as a barrier to seeking help from a healthcare professional, alongside competing time demands and negative attitudes towards help-seeking. These barriers may lead to later diagnosis and poorer cancer survival. Our findings could be used to inform the development of interventions to encourage appropriate help-seeking.
The development and evaluation of an evidence-based guideline programme to improve care in a paediatric emergency department
Authors: Akenroye Ayobami T , Stack Anne M 
Published: July 2015

IntroductionCare guidelines can improve the quality of care by making current evidence available in a concise format. Emergency departments (EDs) are an ideal site for guidelines given the wide variety of presenting conditions and treating providers, and the need for timely decision making. We designed a programme for guideline development and implementation and evaluated its impact in an ED.MethodsThe setting was an urban paediatric ED with an annual volume of 60 000. Common and/or high-risk conditions were identified for guideline development. Following implementation of the guidelines, their impact on effectiveness of care, patient outcomes, efficiency and equitability of care was assessed using a web-based provider survey and performance on identified metrics. Variation in clinical care between providers was assessed using funnel plots.ResultsEleven (11) guidelines were developed and implemented. 3 years after the initiation of the programme, self-reported adherence to recommendations was high (95% for physicians and 89% for nurses). 97% of physicians and 92% of nurses stated that the programme improved the quality of care in the ED. For some guidelines, provider-to-provider care practice variation was reduced significantly. We found reduced disparity in imaging when assessing one guideline. There were also reductions in utilisation of diagnostic tests or therapies. As a balancing measure, the percentage of patients with any of the guideline conditions who returned to the ED within 72 h of discharge did not change from before to after guideline initiation. Overall, 80% of physician and 56% of nurse respondents rated the guideline programme at the highest value.ConclusionsA programme for guideline development and implementation helped to improve efficiency, and standardise and eliminate disparities in emergency care without jeopardising patient outcomes.
Pleistocene submerged landscapes and Palaeolithic archaeology in the tectonically active Aegean region
Authors: Sakellariou D. , Galanidou N. 
Published: July 2015

Abstract
In this paper we review the main, long- and short-term geological and geotectonic processes that have controlled the development of Pleistocene landscapes in the Aegean region above and below the fluctuating sea level. We discuss the potential for further research on reconstruction of submerged landscapes of the continental shelf and beyond with the aim of addressing questions concerning Palaeolithic settlement. The geological, tectonic, morphological and hydrogeological background provides information for the assessment of the natural resources available to hominins. Along with the palaeogeographical evolution of the shallow coastal and shelf areas, they are examined in parallel with the terrestrial archaeological record in order to open windows to future work in a region that has remained marginal to human origins research. On the basis of the multi-variable tectonic evolution and geomorphological configuration of the coastal and shelf areas, we propose to divide the Aegean region into nine geographical units, each with its own geotectonic and morphological history and traits. These units can be further grouped to provide larger neighbouring and culturally meaningful regions, suitable for archaeological analysis, or subdivided to provide smaller target areas in which to work.
Shades of T790M: Intratumor Heterogeneity in EGFR-Mutant Lung Cancer
Authors: Ichihara Eiki , Lovly Christine M. 
Published: July 2015

Abstract
Summary: In the setting of recent exciting clinical results and numerous ongoing trials, Piotrowska and colleagues explore mechanisms of acquired resistance to the mutant-specific EGFR inhibitor rociletinib, and demonstrate that loss of T790M, EGFR amplification, and small-cell transformation are all clinically relevant mechanisms of drug resistance. The authors provide a new paradigm for using quantitative assessment of the EGFR T790M:activation mutation allele frequency ratio to prognosticate responses to rociletinib and also demonstrate that plasma-based assessments of circulating tumor DNA can be used to monitor drug response and the emergence of drug resistance. Cancer Discov; 5(7); 694–6. ©2015 AACR.
See related article by Piotrowska et al., p. 713.