bluuebunny/crossref_metadata_2025 huggingface dataset:
The Argonaute‐binding platform of NRPE1 evolves through modulation of intrinsically disordered repeats
Authors: Trujillo Joshua T. , Beilstein Mark A. , Mosher Rebecca A.
Published: July 2016

Argonaute (Ago) proteins are important effectors in RNA silencing pathways, but they must interact with other machinery to trigger silencing. Ago hooks have emerged as a conserved motif responsible for interaction with Ago proteins, but little is known about the sequence surrounding Ago hooks that must restrict or enable interaction with specific Argonautes.

Here we investigated the evolutionary dynamics of an Ago‐binding platform in NRPE1, the largest subunit of RNA polymerase V. We compared NRPE1 sequences from > 50 species, including dense sampling of two plant lineages.

This study demonstrates that the Ago‐binding platform of NRPE1 retains Ago hooks, intrinsic disorder, and repetitive character while being highly labile at the sequence level. We reveal that loss of sequence conservation is the result of relaxed selection and frequent expansions and contractions of tandem repeat arrays. These factors allow a complete restructuring of the Ago‐binding platform over 50–60 million yr. This evolutionary pattern is also detected in a second Ago‐binding platform, suggesting it is a general mechanism.

The presence of labile repeat arrays in all analyzed NRPE1 Ago‐binding platforms indicates that selection maintains repetitive character, potentially to retain the ability to rapidly restructure the Ago‐binding platform.
Environmental components of childhood obesity prevention interventions: an overview of systematic reviews
Authors: Cauchi D. , Glonti K. , Petticrew M. , Knai C.
Published: July 2016

Childhood obesity has a complex multi‐factorial aetiology grounded in environmental and individual level factors that affect behaviour and outcomes. An ecological, systems‐based approach to addressing childhood obesity is increasingly being advocated. The primary aim of this review is to summarize the evidence reported in systematic reviews on the effectiveness of population‐level childhood obesity prevention interventions that have an environmental component. We conducted a systematic review of reviews published since 1995, employing a standardized search strategy in nine databases. Inclusion criteria required that reviews be systematic and evaluated at least one population‐level, environmental intervention in any setting aimed at preventing or reducing obesity in children (5–18 years). Sixty‐three reviews were included, ten of which were of high quality. Results show modest impact of a broad range of environmental strategies on anthropometric outcomes. Systematic reviews vary in methodological quality, and not all relevant primary studies may be included in each review. To ensure relevance of our findings to practice, we also report on relevant underlying primary studies, providing policy‐relevant recommendations based on the evidence reviewed. Greater standardization of review methods and reporting structures will benefit policymakers and public health professionals seeking informed decision‐making.
The effects of school‐based lifestyle interventions on body mass index and blood pressure: a multivariate multilevel meta‐analysis of randomized controlled trials
Authors: Oosterhoff M. , Joore M. , Ferreira I.
Published: July 2016

Primary prevention of childhood obesity and related hypertension is warrant given that both risk factors are intertwined and track into adulthood. This systematic review and meta‐analysis assess the impact of school‐based lifestyle interventions on children's body mass index (BMI) and blood pressure. We searched databases and prior reviews. Eligibility criteria were the following: randomized controlled trial design, evaluation of a school‐based intervention, targeting children aged 4–12 years, reporting on BMI and/or related cardiovascular risk factors, reporting data on at least one follow‐up moment. The effects on BMI, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were evaluated by means of univariate and multivariate three‐level random effects models. A total of 85 RCTs (91 papers) were included in the meta‐analyses. In univariate models, the pooled effects were −0.072 (95%CI: −0.106; −0.038) for BMI, −0.183 (95%CI: −0.288; −0.078) for SBP and −0.071 (95%CI: −0.185; 0.044) for DBP. In multivariate analyses, the pooled effects of interventions were −0.054 (95%CI: −0.131; 0.022) for BMI, −0.182 (95%CI: −0.266; −0.098) for SBP and −0.144 (95%CI: −0.230; −0.057) for DBP. Parental involvement accentuated the beneficial effects of interventions. School‐based lifestyle prevention interventions result in beneficial changes in children's BMI and blood pressure, and the effects on the latter may be stronger than and accrue independently from those in the former.
Omentum and bone marrow: how adipocyte‐rich organs create tumour microenvironments conducive for metastatic progression
Authors: Chkourko Gusky H. , Diedrich J. , MacDougald O. A. , Podgorski I.
Published: July 2016

A number of clinical studies have linked adiposity with increased cancer incidence, progression and metastasis, and adipose tissue is now being credited with both systemic and local effects on tumour development and survival. Adipocytes, a major component of benign adipose tissue, represent a significant source of lipids, cytokines and adipokines, and their presence in the tumour microenvironment substantially affects cellular trafficking, signalling and metabolism. Cancers that have a high predisposition to metastasize to the adipocyte‐rich host organs are likely to be particularly affected by the presence of adipocytes. Although our understanding of how adipocytes influence tumour progression has grown significantly over the last several years, the mechanisms by which adipocytes regulate the metastatic niche are not well‐understood. In this review, we focus on the omentum, a visceral white adipose tissue depot, and the bone, a depot for marrow adipose tissue, as two distinct adipocyte‐rich organs that share common characteristic: they are both sites of significant metastatic growth. We highlight major differences in origin and function of each of these adipose depots and reveal potential common characteristics that make them environments that are attractive and conducive to secondary tumour growth. Special attention is given to how omental and marrow adipocytes modulate the tumour microenvironment by promoting angiogenesis, affecting immune cells and altering metabolism to support growth and survival of metastatic cancer cells.
La vie mentie de Michel del Castillo
Authors: Lindberg Svante
Published: July 2016

Dans cet article, je vise à élucider les rapports au lieu culturel espagnol dans un roman de la production tardive de Michel del Castillo (né en 1933), La vie mentie (2007). Il s'agit d'étudier les thématiques de la mémoire du passé et de la culture de l'Espagne. J'aborde deux visions de la culture : culture « atavique » et culture « composite », telles que définies par Édouard Glissant dans sa poétique de la filiation et de la Relation. Sont discutées aussi les questions du devoir de mémoire, du lieu espagnol essentialiste, et du lieu espagnol comme espace de projection personnelle. Le rapport avec l'Espagne est‐il à voir comme un rapport culturel atavique  ou s'agit‐il d'un rapport culturel composite ? Je discute également le rôle de l'écrivain Michel del Castillo en tant qu'écrivain de langue française œuvrant dans un espace limitrophe entre littérature française, littérature espagnole et littérature‐monde.
Performance of Atrial Fibrillation Detection in a New Single‐Chamber ICD
Authors: DESHMUKH ABHISHEK , BROWN MARK L. , HIGGINS ELISE , SCHOUSEK BRIAN , ABEYRATNE ATHULA , ROVARIS GIOVANNI , FRIEDMAN PAUL A.
Published: July 2016

Background

Patients with implantable cardioverter defibrillators (ICDs) often have a history of atrial fibrillation (AF) or will develop AF after device implant. Optimal management of ICD patients includes early diagnosis of AF and monitoring of AF burden. We evaluated the performance of an algorithm for monitoring AF in single‐chamber ICDs.

Methods

The RR interval variability‐based detection algorithm determines RR variability by creating a Lorenz plot of the change in RR intervals for the most recent interval pair versus the previous interval pair. A new plot is created every 2 minutes and the AF evidence score of the plot is computed. Patient RR interval data from several Holter databases were pooled to test the performance of the AF detection algorithm.

Results

In total, 187 recordings from 186 patients were used to assess the performance of the AF detection algorithm integrated into a single‐chamber ICD by comparing the ICD detection results to the Holter annotated truth. Thirty‐five of 186 patients had a total of 94 AF episodes in their Holter recordings lasting a total of 250.5 hours (mean episode duration 7.2 hours). The generalized estimating equations‐adjusted estimate of episode sensitivity was 94.8% with 95% lower confidence limit of 87.2%. Gross duration sensitivity was 95.0% for AF episodes of at least 6 minutes duration with gross duration specificity of 99.6%.

Conclusion

This RR interval‐based AF detection algorithm performs well with high sensitivity and specificity. Integration of this algorithm into single‐chamber ICDs will help monitor and detect AF, thus facilitating optimal therapy to prevent AF‐related sequelae.
A multilevel investigation to discover why Kandelia candel thrives in high salinity
Authors: Wang Lingxia , Pan Dezhuo , Lv Xiaojie , Cheng Chi‐Lien , Li Jian , Liang Wenyu , Xing Jianhong , Chen Wei
Published: July 2016

The halophilic mangrove species Kandelia candel is an excellent model for understanding why halophytes thrive in high salinity. Preliminary transcriptomic analyses revealed that genes involved in diverse functions, such as in phenylpropanoid and amino acid metabolisms, and those in DNA replication and damage repair were highly responsive to salt stress. Proteomic analyses revealed that the proteins involved in light reaction of photosynthesis, amino acid and carbohydrate metabolisms, secondary metabolite biosynthesis and posttranslational modification showed increased levels in response to salt stress. The metabolisms of phenylpropanoids and amino acids under salt stress were systematically examined based on the preliminary omics analyses. The activities of phenylpropanoid biosynthetic enzymes and the contents of phenols, flavonoids, anthocyanins and lignins were significantly increased under salt stress. In the free amino acid pool, glutamate was the most abundant. Together with γ‐aminobutyric acid, glutamate levels further increased, while proline levels remained unchanged in response to salt stress. These findings point to the potential importance of phenylpropanoids and free amino acids in salt tolerance of K. candel that have been observed, but not systemically investigated at the levels of gene expression, enzyme activity and metabolite accumulation in glycophytes and non‐tree halophytes.
Working memory maintenance is sufficient to reduce state anxiety
Authors: Balderston Nicholas L. , Quispe‐Escudero David , Hale Elizabeth , Davis Andrew , O'Connell Katherine , Ernst Monique , Grillon Christian
Published: July 2016

According to the attentional control theory (ACT) proposed by Eysenck and colleagues, anxiety interferes with cognitive processing by prioritizing bottom‐up attentional processes over top‐down attentional processes, leading to competition for access to limited resources in working memory, particularly the central executive (Eysenck, Derakshan, Santos, & Calvo, ). However, previous research using the n‐back working memory task suggests that working memory load also reduces state anxiety. Assuming that similar mechanisms underlie the effect of anxiety on cognition, and the effect of cognition on anxiety, one possible implication of the ACT would suggest that the reduction of state anxiety with increasing working memory load is driven by activation of central executive attentional control processes. We tested this hypothesis using the Sternberg working memory paradigm, where maintenance processes can be isolated from central executive processes (Altamura et al., ; Sternberg, ). Consistent with the n‐back results, subjects showed decreased state anxiety during the maintenance period of high‐load trials relative to low‐load trials, suggesting that maintenance processes alone are sufficient to achieve this state anxiety reduction. Given that the Sternberg task does not require central executive engagement, these results are not consistent with an implication of the ACT where the cognition/anxiety relationship and anxiety/cognition relationship are mediated by similar central executive mechanisms. Instead, we propose an extension of the ACT such that engaging working memory maintenance suppresses state anxiety in a load‐dependent manner. Furthermore, we hypothesize that the efficacy of this effect may moderate the effect of trait anxiety on cognition.
Assessing the efficacy of a single‐unit red blood cell transfusion policy at a multisite transfusion service using a computerized retrospective audit
Authors: Covello T. P. C. , Quinn J. G. , Kumar‐Misir A. , Watson S. , Almohammadi M. , Crocker B. D. , Conrad D. M. , Tennankore K. , Sadek I. , Kahwash E. , Cheng C. K.
Published: July 2016

Background and Objectives

In 2013, an Eastern Canada blood bank implemented a new policy to reduce red cell transfusion. The policy mandated clinical or laboratory reassessment of stable, non‐bleeding patients after each unit transfused, before issuing subsequent units. A computerized audit assessed the policy's effectiveness.

Materials and Methods

This retrospective cohort study compares the policy's effect on transfusion practice across three groups of adult inpatients: haematology, surgery and internal medicine. Compliance was inferred from increases in the proportion of single‐unit red cell transfusions among all single‐ and double‐unit transfusions. Outcome variables included transfusion intensity (red cell units administered per admission involving a transfusion) and pretransfusion haemoglobin levels.

Results

Each group had more transfusions issued as single units during the ten months following policy enforcement. In haematology patients, single‐unit transfusions increased from 17% to 89% and transfusion intensity decreased (median: 2–2, Q1: 2–1, Q3: 6–4, P < 0·001). Single‐unit transfusions increased from 57% to 94% in medicine patients and from 63% to 87% in surgery patients. Transfusion intensity also decreased in surgical patients (median: 2–1, Q1: 1–1, Q3: 2–2, P < 0·001) and in medicine patients (median: 2–1, Q1: 1–1, Q3: 2–2, P = 0·008). No group showed a clinically significant change in pretransfusion haemoglobin levels.

Conclusion

The audit demonstrated significant compliance with a single‐unit transfusion policy. Transfusion intensity decreased in all groups despite no clinically significant change in pretransfusion haemoglobin levels.
Vascular responsiveness measured by tissue oxygen saturation reperfusion slope is sensitive to different occlusion durations and training status
Authors: McLay Kaitlin M. , Gilbertson James E. , Pogliaghi Silvia , Paterson Donald H. , Murias Juan M.
Published: July 2016

New Findings

What is the central question of this study?

Is the near‐infrared spectroscopy‐derived measure of tissue oxygen saturation () reperfusion slope sensitive to a range of ischaemic conditions, and do differences exist between trained and untrained individuals?

What is the main finding and its importance?

The reperfusion rate is sensitive to different occlusion durations, and changes in the reperfusion slope in response to a variety of ischaemic challenges can be used to detect differences between two groups. These data indicate that near‐infrared spectroscopy‐derived measures of , specifically the reperfusion slope following a vascular occlusion, can be used as a sensitive measure of vascular responsiveness.

The reperfusion rate of near‐infrared spectroscopy‐derived measures of tissue oxygen saturation () represents vascular responsiveness. This study examined whether the reperfusion slope of is sensitive to different ischaemic conditions (i.e. a dose–response relationship) and whether differences exist between two groups of different fitness levels. Nine healthy trained (T; age 25 ± 3 years; maximal oxygen uptake 63.4 ± 6.7 ml kg−1 min−1) and nine healthy untrained men (UT; age 21 ± 1 years; maximal oxygen uptake 46.6 ± 2.5 ml kg−1 min−1) performed a series of vascular occlusion tests of different durations (30 s, 1, 2, 3 and 5 min), each separated by 30 min. The was measured over the tibialis anterior using near‐infrared spectroscopy, with the reperfusion slope calculated as the upslope during 10 s following cuff release. The reperfusion slope was steeper in T compared with UT at all occlusion durations (P < 0.05). For the T group, the reperfusion slopes for 30 s and 1 min occlusions were less than for all longer durations (P < 0.05). The reperfusion slope following 2 min occlusion was similar to that for 3 min (P > 0.05), but both were less steep than for 5 min of occlusion. In UT, the reperfusion slope at 30 s was smaller than for all longer occlusion durations (P < 0.05), and 1 min occlusion resulted in a reperfusion slope that was less steep than following 2 and 3 min (P < 0.05), albeit not different from 5 min (P > 0.05). The present study demonstrated that the reperfusion rate of is sensitive to different occlusion durations, and that changes in the reperfusion rate in response to a variety of ischaemic challenges can be used to detect differences in vascular responsiveness between trained and untrained groups.
Assessing auditory evoked potentials of wild harbor porpoises (Phocoena phocoena)
Authors: Ruser Andreas , Dähne Michael , van Neer Abbo , Lucke Klaus , Sundermeyer Janne , Siebert Ursula , Houser Dorian S. , Finneran James J. , Everaarts Eligius , Meerbeek Jolanda , Dietz Rune , Sveegaard Signe , Teilmann Jonas
Published: July 2016

Testing the hearing abilities of marine mammals under water is a challenging task. Sample sizes are usually low, thus limiting the ability to generalize findings of susceptibility towards noise influences. A method to measure harbor porpoise hearing thresholds in situ in outdoor conditions using auditory steady state responses of the brainstem was developed and tested. The method was used on 15 live-stranded animals from the North Sea during rehabilitation, shortly before release into the wild, and on 12 wild animals incidentally caught in pound nets in Denmark (inner Danish waters). Results indicated that although the variability between individuals is wide, the shape of the hearing curve is generally similar to previously published results from behavioral trials. Using 10-kHz frequency intervals between 10 and 160 kHz, best hearing was found between 120 and 130 kHz. Additional testing using one-third octave frequency intervals (from 16 to 160 kHz) allowed for a much faster hearing assessment, but eliminated the fine scale threshold characteristics. For further investigations, the method will be used to better understand the factors influencing sensitivity differences across individuals and to establish population-level parameters describing hearing abilities of harbor porpoises.
Embodied Experiences of Empowerment Among Female Tackle Football Players
Authors: Liechty Toni , Willfong Fleesha , Sveinson Katherine
Published: July 2016

The purpose of this study was to explore the embodied nature of empowerment among women who play tackle football. Data collection involved semistructured interviews with 15 female football players in Western Canada. Interviews were audio-recorded, transcribed verbatim and analyzed thematically. Three themes emerged from the data suggesting that playing football was empowering as women experienced: a) feelings of strength related to the physicality of the game; b) a sense of breaking boundaries as they participated despite challenges; and c) a sense of belonging to the team which led to positive outcomes such as increased confidence and selfacceptance. The findings of this study highlight the embodied nature of empowerment that comes through participation in sport and characteristics of contact team sport that can facilitate empowerment for women.
The endothelial adaptor molecule TSAd is required for VEGF-induced angiogenic sprouting through junctional c-Src activation
Authors: Gordon Emma J. , Fukuhara Daisuke , Weström Simone , Padhan Narendra , Sjöström Elisabet O. , van Meeteren Laurens , He Liqun , Orsenigo Fabrizio , Dejana Elisabetta , Bentley Katie , Spurkland Anne , Claesson-Welsh Lena
Published: July 2016

The adaptor protein TSAd helps endothelial cells disconnect so that they can migrate and form new blood vessels.
Facilitation of TRPV4 by TRPV1 is required for itch transmission in some sensory neuron populations
Authors: Kim Seungil , Barry Devin M. , Liu Xian-Yu , Yin Shijin , Munanairi Admire , Meng Qing-Tao , Cheng Wei , Mo Ping , Wan Li , Liu Shen-Bin , Ratnayake Kasun , Zhao Zhong-Qiu , Gautam Narasimhan , Zheng Jie , Karunarathne W. K. Ajith , Chen Zhou-Feng
Published: July 2016

Sensory neurons use a pair of TRP channels to respond to some itch-inducing chemicals.
Fullerene Derivatives Strongly Inhibit HIV-1 Replication by Affecting Virus Maturation without Impairing Protease Activity
Authors: Martinez Zachary S. , Castro Edison , Seong Chang-Soo , Cerón Maira R. , Echegoyen Luis , Llano Manuel
Published: July 2016

Three compounds (1, 2, and 3) previously reported to inhibit HIV-1 replication and/or
in vitro
activity of reverse transcriptase were studied, but only fullerene derivatives 1 and 2 showed strong antiviral activity on the replication of HIV-1 in human CD4
+
T cells. However, these compounds did not inhibit infection by single-round infection vesicular stomatitis virus glycoprotein G (VSV-G)-pseudotyped viruses, indicating no effect on the early steps of the viral life cycle. In contrast, analysis of single-round infection VSV-G-pseudotyped HIV-1 produced in the presence of compound 1 or 2 showed a complete lack of infectivity in human CD4
+
T cells, suggesting that the late stages of the HIV-1 life cycle were affected. Quantification of virion-associated viral RNA and p24 indicates that RNA packaging and viral production were unremarkable in these viruses. However, Gag and Gag-Pol processing was affected, as evidenced by immunoblot analysis with an anti-p24 antibody and the measurement of virion-associated reverse transcriptase activity, ratifying the effect of the fullerene derivatives on virion maturation of the HIV-1 life cycle. Surprisingly, fullerenes 1 and 2 did not inhibit HIV-1 protease in an
in vitro
assay at the doses that potently blocked viral infectivity, suggesting a protease-independent mechanism of action. Highlighting the potential therapeutic relevance of fullerene derivatives, these compounds block infection by HIV-1 resistant to protease and maturation inhibitors.
Evaluation of Vancomycin Exposures Associated with Elevations in Novel Urinary Biomarkers of Acute Kidney Injury in Vancomycin-Treated Rats
Authors: Rhodes Nathaniel J. , Prozialeck Walter C. , Lodise Thomas P. , Venkatesan Natarajan , O'Donnell J. Nicholas , Pais Gwendolyn , Cluff Cameron , Lamar Peter C. , Neely Michael N. , Gulati Anil , Scheetz Marc H.
Published: July 2016

Vancomycin has been associated with acute kidney injury (AKI). However, the pharmacokinetic/toxicodynamic relationship for AKI is not well defined. Allometrically scaled vancomycin exposures were used to assess the relationship between vancomycin exposure and AKI. Male Sprague-Dawley rats received clinical-grade vancomycin in normal saline (NS) as intraperitoneal (i.p.) injections for 24- to 72-h durations with doses ranging 0 to 200 mg/kg of body weight divided once or twice daily. Urine was collected over the protocol's final 24 h. Renal histopathology was qualitatively scored. Urinary biomarkers (e.g., cystatin C, clusterin, kidney injury molecule 1 [KIM-1], osteopontin, lipocalin 2/neutrophil gelatinase-associated lipocalin 2) were assayed using a Luminex xMAP system. Plasma vancomycin concentrations were assayed by high-performance liquid chromatography with UV detection. A three-compartment vancomycin pharmacokinetic model was fit to the data with the Pmetrics package for R. The exposure-response in the first 24 h was evaluated using Spearman's nonparametric correlation coefficient (rs) values for the area under the concentration-time curve during the first 24 h (AUC0–24), the maximum concentration in plasma during the first 24 h (Cmax0–24), and the lowest (minimum) concentration in plasma after the dose closest to 24 h (Cmin0–24). A total of 52 rats received vancomycin (n= 42) or NS (n= 10). The strongest exposure-response correlations were observed between AUC0–24and Cmax0–24and urinary AKI biomarkers. Exposure-response correlations (rsvalues) for AUC0–24, Cmax0–24, and Cmin0–24were 0.37, 0.39, and 0.22, respectively, for clusterin; 0.42, 0.45, and 0.26, respectively, for KIM-1; and 0.52, 0.55, and 0.42, respectively, for osteopontin. However, no differences in histopathological scores were observed. Optimal sampling times after administration of the i.p. dose were 0.25, 0.75, 2.75, and 8 h for the once-daily dosing schemes and 0.25, 1.25, 14.5, and 17.25 h for the twice-daily dosing schemes. Our observations suggest that AUC0–24or Cmax0–24correlates with increases in urinary AKI biomarkers.
Population Pharmacokinetic Modeling of Tribendimidine Metabolites in Opisthorchis viverrini-Infected Adults
Authors: Vanobberghen Fiona , Penny Melissa A. , Duthaler Urs , Odermatt Peter , Sayasone Somphou , Keiser Jennifer , Tarning Joel
Published: July 2016

There is a pressing need for alternative treatments against the liver fluke
Opisthorchis viverrini
. Oral tribendimidine is a promising candidate, but its population pharmacokinetic properties are unknown. Two phase IIa trials were conducted in Laos in
O. viverrini
-infected adults receiving single oral doses of 25 to 600 mg tribendimidine administered as different formulations in each study (study 1 used 200-mg tablets, and study 2 used 50-mg tablets). Venous whole blood, plasma, and capillary dried blood spots were sampled frequently from 68 adults, and concentrations of the tribendimidine metabolites dADT (deacetylated amidantel) and adADT (acetylated dADT) were measured. Population pharmacokinetics were assessed by using nonlinear mixed-effects modeling. The relationship between drug exposure and cure (assessed at 21 days posttreatment) was evaluated by using univariable logistic regression. A six-transit compartment absorption model with a one-disposition compartment for each metabolite described the data well. Compared to the 50-mg formulation (study 2), the 200-mg formulation (study 1) had a 40.1% higher mean transit absorption time, a 113% higher dADT volume of distribution, and a 364% higher adADT volume of distribution. Each 10-year increase in age was associated with a 12.7% lower dADT clearance and a 21.2% lower adADT clearance. The highest cure rates (≥55%) were observed with doses of ≥100 mg. Higher dADT, but not adADT, peak concentrations and exposures were associated with cure (
P
= 0.004 and 0.003, respectively). For the first time, population pharmacokinetics of tribendimidine have been described. Known differences in the 200-mg versus 50-mg formulations were captured by covariate modeling. Further studies are needed to validate the structural model and confirm covariate relationships. (This study has been registered with the ISRCTN Registry under no. ISRCTN96948551.)
Targeting Multiple Aminoacyl-tRNA Synthetases Overcomes the Resistance Liabilities Associated with Antibacterial Inhibitors Acting on a Single Such Enzyme
Authors: Randall Christopher P. , Rasina Dace , Jirgensons Aigars , O'Neill Alex J.
Published: July 2016

Bacterial aminoacyl-tRNA synthetases (aaRSs) represent promising antibacterial drug targets. Unfortunately, the aaRS inhibitors that have to date reached clinical trials are subject to rapid resistance development through mutation, a phenomenon that limits their potential clinical utility. Here, we confirm the intuitively correct idea that simultaneous targeting of two different aaRS enzymes prevents the emergence of spontaneous bacterial resistance at high frequency, a finding that supports the development of multitargeted anti-aaRS therapies.
Emergence and Plasmid Analysis of Klebsiella pneumoniae KP01 Carrying
bla
GES-5
from Guangzhou, China
Authors: Chen Ding-Qiang , Wu Ai-Wu , Yang Ling , Su Dan-Hong , Lin Yong-ping , Hu Yan-Wei , Zheng Lei , Wang Qian
Published: July 2016

Klebsiella pneumoniae
strain KP01 carrying
bla
GES-5
was identified from a patient in Guangzhou, China. High-throughput sequencing assigned
bla
GES-5
to a 28.5-kb nonconjugative plasmid, pGES-GZ. A 13-kb plasmid backbone sequence on pGES-GZ was found to share high sequence identities with plasmids from Gram-negative nonfermenters. A novel class 1 integron carrying a gene cassette array of
orf28-orf28-bla
GES-5
was identified on pGES-GZ, within which
orf28
encoded a hypothetical protein possibly correlated to fosfomycin resistance.
De Novo
Characterization of Genes That Contribute to High-Level Ciprofloxacin Resistance in Escherichia coli
Authors: Tran Thu , Ran Qinghong , Ostrer Lev , Khodursky Arkady
Published: July 2016

Sensitization of resistant bacteria to existing antibiotics depends on the identification of candidate targets whose activities contribute to resistance. Using a transposon insertion library in an
Escherichia coli
mutant that was 2,000 times less susceptible to ciprofloxacin than its parent and the relative fitness scores, we identified 19 genes that contributed to the acquired ciprofloxacin resistance and mapped the shortest genetic path that increased the antibiotic susceptibility of the resistant bacteria back to a near wild-type level.
Efficacy Projection of Obiltoxaximab for Treatment of Inhalational Anthrax across a Range of Disease Severity
Authors: Yamamoto Brent J. , Shadiack Annette M. , Carpenter Sarah , Sanford Daniel , Henning Lisa N. , O'Connor Edward , Gonzales Nestor , Mondick John , French Jonathan , Stark Gregory V. , Fisher Alan C. , Casey Leslie S. , Serbina Natalya V.
Published: July 2016

Inhalational anthrax has high mortality even with antibiotic treatment, and antitoxins are now recommended as an adjunct to standard antimicrobial regimens. The efficacy of obiltoxaximab, a monoclonal antibody against anthrax protective antigen (PA), was examined in multiple studies conducted in two animal models of inhalational anthrax. A single intravenous bolus of 1 to 32 mg/kg of body weight obiltoxaximab or placebo was administered to New Zealand White rabbits (two studies) and cynomolgus macaques (4 studies) at disease onset (significant body temperature increase or detection of serum PA) following lethal challenge with aerosolized
Bacillus anthracis
spores. The primary endpoint was survival. The relationship between efficacy and disease severity, defined by pretreatment bacteremia and toxemia levels, was explored. In rabbits, single doses of 1 to 16 mg/kg obiltoxaximab led to 17 to 93% survival. In two studies, survival following 16 mg/kg obiltoxaximab was 93% and 62% compared to 0% and 0% for placebo (
P
= 0.0010 and
P
= 0.0013, respectively). Across four macaque studies, survival was 6.3% to 78.6% following 4 to 32 mg/kg obiltoxaximab. In two macaque studies, 16 mg/kg obiltoxaximab reduced toxemia and led to survival rates of 31%, 35%, and 47% versus 0%, 0%, and 6.3% with placebo (
P
= 0.0085,
P
= 0.0053,
P
= 0.0068). Pretreatment bacteremia and toxemia levels inversely correlated with survival. Overall, obiltoxaximab monotherapy neutralized PA and increased survival across the range of disease severity, indicating clinical benefit of toxin neutralization with obiltoxaximab in both early and late stages of inhalational anthrax.
The HMW1 and HMW2 Adhesins Enhance the Ability of Nontypeable Haemophilus influenzae To Colonize the Upper Respiratory Tract of Rhesus Macaques
Authors: Rempe Katherine A. , Porsch Eric A. , Wilson Jolaine M. , St. Geme Joseph W.
Published: July 2016

NontypeableHaemophilus influenzae(NTHi) initiates infection by colonizing the upper respiratory tract and is a common cause of localized respiratory tract disease. Previous work has established that the NTHi HMW1 and HMW2 proteins are potent adhesins that mediate efficientin vitroadherence to cultured human respiratory epithelial cells. In this study, we used a rhesus macaque model to assess the contributions of HMW1 and HMW2 toin vivocolonization. In experiments involving inoculation of individual isogenic derivatives of NTHi strain 12, the parent strain expressing both HMW1 and HMW2 and the mutant strains expressing either HMW1 or HMW2 were able to colonize more frequently than the double mutant strain lacking HMW1 and HMW2. In competition experiments, the parent strain efficiently outcompeted the double mutant lacking HMW1 and HMW2. Colonization with strains expressing HMW2 resulted in development of antibody against HMW2 in a number of the animals, demonstrating that colonization can stimulate an antibody response. In conclusion, we have established that the HMW1 and HMW2 adhesins play a major role in facilitating colonization of the upper respiratory tract of rhesus macaques, in some cases associated with stimulation of an immune response.
Cooperation of PD-1 and LAG-3 Contributes to T-Cell Exhaustion in Anaplasma marginale-Infected Cattle
Authors: Okagawa Tomohiro , Konnai Satoru , Deringer James R. , Ueti Massaro W. , Scoles Glen A. , Murata Shiro , Ohashi Kazuhiko , Brown Wendy C.
Published: July 2016

The CD4
+
T-cell response is central for the control of
Anaplasma marginale
infection in cattle. However, the infection induces a functional exhaustion of antigen-specific CD4
+
T cells in cattle immunized with
A. marginale
outer membrane proteins or purified outer membranes (OMs), which presumably facilitates the persistence of this rickettsia. In the present study, we hypothesize that T-cell exhaustion following infection is induced by the upregulation of immunoinhibitory receptors on T cells, such as programmed death 1 (PD-1) and lymphocyte activation gene 3 (LAG-3). OM-specific T-cell responses and the kinetics of PD-1-positive (PD-1
+
) LAG-3
+
exhausted T cells were monitored in
A. marginale
-challenged cattle previously immunized with OMs. Consistent with data from previous studies, OM-specific proliferation of peripheral blood mononuclear cells (PBMCs) and interferon gamma (IFN-γ) production were significantly suppressed in challenged animals by 5 weeks postinfection (wpi). In addition, bacteremia and anemia also peaked in these animals at 5 wpi. Flow cytometric analysis revealed that the percentage of PD-1
+
LAG-3
+
T cells in the CD4
+
, CD8
+
, and γδ T-cell populations gradually increased and also peaked at 5 wpi. A large increase in the percentage of LAG-3
+
γδ T cells was also observed. Importantly,
in vitro
, the combined blockade of the PD-1 and LAG-3 pathways partially restored OM-specific PBMC proliferation and IFN-γ production at 5 wpi. Taken together, these results indicate that coexpression of PD-1 and LAG-3 on T cells contributes to the rapid exhaustion of
A. marginale
-specific T cells following infection and that these immunoinhibitory receptors regulate T-cell responses during bovine anaplasmosis.
Disease and Carrier Isolates of Neisseria meningitidis Cause G
1
Cell Cycle Arrest in Human Epithelial Cells
Authors: von Papen Michael , Oosthuysen Wilhelm F. , Becam Jérôme , Claus Heike , Schubert-Unkmeir Alexandra
Published: July 2016

Microbial pathogens have developed several mechanisms to modulate and interfere with host cell cycle progression. In this study, we analyzed the effect of the human pathogen
Neisseria meningitidis
on the cell cycle of epithelial cells. Two pathogenic isolates, as well as two carrier isolates, were tested for their ability to adhere to and invade into the epithelial cell lines Detroit 562 and NP69 and to modulate the cell cycle. We found that all isolates adhered equally well to both Detroit 562 and NP69 cells, whereas the carrier isolates were significantly less invasive. Using propidium iodide staining and 5-ethynyl-2′-deoxyuridine pulse-labeling, we provide evidence that meningococcal infection arrested cells in the G
1
phase of the cell cycle at 24 h postinfection. In parallel, a significant decrease of cells in the S phase was observed. Interestingly, G
1
-phase arrest was only induced after infection with live bacteria but not with heat-killed bacteria. By Western blotting we demonstrate that bacterial infection resulted in a decreased protein level of the cell cycle regulator cyclin D1, whereas cyclin E expression levels were increased. Furthermore,
N. meningitidis
infection induced an accumulation of the cyclin-dependent kinase inhibitor (CKI) p21
WAF1/CIP1
that was accompanied by a redistribution of this CKI to the cell nucleus, as shown by immunofluorescence analysis. Moreover, the p27
CIP1
CKI was redistributed and showed punctate foci in infected cells. In summary, we present data that
N. meningitidis
can interfere with the processes of host cell cycle regulation.
Beyond Tryptophan Synthase: Identification of Genes That Contribute to Chlamydia trachomatis Survival during Gamma Interferon-Induced Persistence and Reactivation
Authors: Muramatsu Matthew K. , Brothwell Julie A. , Stein Barry D. , Putman Timothy E. , Rockey Daniel D. , Nelson David E.
Published: July 2016

Chlamydia trachomatis
can enter a viable but nonculturable state
in vitro
termed persistence. A common feature of
C. trachomatis
persistence models is that reticulate bodies fail to divide and make few infectious progeny until the persistence-inducing stressor is removed. One model of persistence that has relevance to human disease involves tryptophan limitation mediated by the host enzyme indoleamine 2,3-dioxygenase, which converts
l
-tryptophan to
N
-formylkynurenine. Genital
C. trachomatis
strains can counter tryptophan limitation because they encode a tryptophan-synthesizing enzyme. Tryptophan synthase is the only enzyme that has been confirmed to play a role in interferon gamma (IFN-γ)-induced persistence, although profound changes in chlamydial physiology and gene expression occur in the presence of persistence-inducing stressors. Thus, we screened a population of mutagenized
C. trachomatis
strains for mutants that failed to reactivate from IFN-γ-induced persistence. Six mutants were identified, and the mutations linked to the persistence phenotype in three of these were successfully mapped. One mutant had a missense mutation in tryptophan synthase; however, this mutant behaved differently from previously described synthase null mutants. Two hypothetical genes of unknown function,
ctl0225
and
ctl0694
, were also identified and may be involved in amino acid transport and DNA damage repair, respectively. Our results indicate that
C. trachomatis
utilizes functionally diverse genes to mediate survival during and reactivation from persistence in HeLa cells.
Electron Acceptors Induce Secretion of Enterotoxigenic Escherichia coli Heat-Labile Enterotoxin under Anaerobic Conditions through Promotion of GspD Assembly
Authors: Lu Xi , Fu Enqing , Xie Yonghong , Jin Faguang
Published: July 2016

Heat-labile enterotoxin (LT), the major virulence factor of enterotoxigenic
Escherichia coli
(ETEC), can lead to severe diarrhea and promotes ETEC adherence to intestinal epithelial cells. Most previous
in vitro
studies focused on ETEC pathogenesis were conducted under aerobic conditions, which do not reflect the real situation of ETEC infection because the intestine is anoxic. In this study, the expression and secretion of LT under anaerobic or microaerobic conditions were determined; LT was not efficiently secreted into the supernatant under anaerobic or microaerobic conditions unless terminal electron acceptors (trimethylamine
N
-oxide dihydrate [TMAO] or nitrate) were available. Furthermore, we found that the restoration effects of TMAO and nitrate on LT secretion could be inhibited by amytal or Δ
torCAD
and Δ
narG
E. coli
strains, indicating that LT secretion under anaerobic conditions was dependent on the integrity of the respiratory chain. At the same time, electron acceptors increase the ATP level of ETEC, but this increase was not the main reason for LT secretion. Subsequently, the relationship between the integrity of the respiratory chain and the function of the type II secretion system was determined. The GspD protein, the secretin of ETEC, was assembled under anaerobic conditions and was accompanied by LT secretion when TMAO or nitrate was added. Our data also demonstrated that TMAO and nitrate could not induce the GspD assembly and LT secretion in Δ
torCAD
and Δ
narG
strains, respectively. Moreover, GspD assembly under anaerobic conditions was assisted by the pilot protein YghG.
Chimeric Coupling Proteins Mediate Transfer of Heterologous Type IV Effectors through the Escherichia coli pKM101-Encoded Conjugation Machine
Authors: Whitaker Neal , Berry Trista M. , Rosenthal Nathan , Gordon Jay E. , Gonzalez-Rivera Christian , Sheehan Kathy B. , Truchan Hilary K. , VieBrock Lauren , Newton Irene L. G. , Carlyon Jason A. , Christie Peter J.
Published: July 2016

Bacterial type IV secretion systems (T4SSs) are composed of two major subfamilies, conjugation machines dedicated to DNA transfer and effector translocators for protein transfer. We show here that the
Escherichia coli
pKM101-encoded conjugation system, coupled with chimeric substrate receptors, can be repurposed for transfer of heterologous effector proteins. The chimeric receptors were composed of the N-terminal transmembrane domain of pKM101-encoded TraJ fused to soluble domains of VirD4 homologs functioning in
Agrobacterium tumefaciens
,
Anaplasma phagocytophilum
, or
Wolbachia pipientis
. A chimeric receptor assembled from
A. tumefaciens
VirD4 (VirD4
At
) mediated transfer of a MOBQ plasmid (pML122) and
A. tumefaciens
effector proteins (VirE2, VirE3, and VirF) through the pKM101 transfer channel. Equivalent chimeric receptors assembled from the rickettsial VirD4 homologs similarly supported the transfer of known or candidate effectors from rickettsial species. These findings establish a proof of principle for use of the dedicated pKM101 conjugation channel, coupled with chimeric substrate receptors, to screen for translocation competency of protein effectors from recalcitrant species. Many T4SS receptors carry sequence-variable C-terminal domains (CTDs) with unknown function. While VirD4
At
and the TraJ/VirD4
At
chimera with their CTDs deleted supported pML122 transfer at wild-type levels, ΔCTD variants supported transfer of protein substrates at strongly diminished or elevated levels. We were unable to detect binding of VirD4
At
's CTD to the VirE2 effector, although other VirD4
At
domains bound this substrate
in vitro
. We propose that CTDs evolved to govern the dynamics of substrate presentation to the T4SS either through transient substrate contacts or by controlling substrate access to other receptor domains.

IMPORTANCE
Bacterial type IV secretion systems (T4SSs) display striking versatility in their capacity to translocate DNA and protein substrates to prokaryotic and eukaryotic target cells. A hexameric ATPase, the type IV coupling protein (T4CP), functions as a substrate receptor for nearly all T4SSs. Here, we report that chimeric T4CPs mediate transfer of effector proteins through the
Escherichia coli
pKM101-encoded conjugation system. Studies with these repurposed conjugation systems established a role for acidic C-terminal domains of T4CPs in regulating substrate translocation. Our findings advance a mechanistic understanding of T4CP receptor activity and, further, support a model in which T4SS channels function as passive conduits for any DNA or protein substrates that successfully engage with and pass through the T4CP specificity checkpoint.
Germinants and Their Receptors in Clostridia
Authors: Bhattacharjee Disha , McAllister Kathleen N. , Sorg Joseph A.
Published: July 2016

Many anaerobic spore-forming clostridial species are pathogenic, and some are industrially useful. Although many are strict anaerobes, the bacteria persist under aerobic and growth-limiting conditions as multilayered metabolically dormant spores. For many pathogens, the spore form is what most commonly transmits the organism between hosts. After the spores are introduced into the host, certain proteins (germinant receptors) recognize specific signals (germinants), inducing spores to germinate and subsequently grow into metabolically active cells. Upon germination of the spore into the metabolically active vegetative form, the resulting bacteria can colonize the host and cause disease due to the secretion of toxins from the cell. Spores are resistant to many environmental stressors, which make them challenging to remove from clinical environments. Identifying the conditions and the mechanisms of germination in toxin-producing species could help develop affordable remedies for some infections by inhibiting germination of the spore form. Unrelated to infectious disease, spore formation in species used in the industrial production of chemicals hinders the optimum production of the chemicals due to the depletion of the vegetative cells from the population. Understanding spore germination in acetone-butanol-ethanol-producing species can help boost the production of chemicals, leading to cheaper ethanol-based fuels. Until recently, clostridial spore germination is assumed to be similar to that ofBacillus subtilis. However, recent studies inClostridium difficileshed light on a mechanism of spore germination that has not been observed in any endospore-forming organisms to date. In this review, we focus on the germinants and the receptors recognizing these germinants in various clostridial species.
Rare allergic reaction of the kidney: sitagliptin-induced acute tubulointerstitial nephritis
Authors: Alsaad Ali A , Dhannoon Sarah M , Pantin Sally-Ann L , Porter Ivan E
Published: July 2016

A 56-year-old man with a history of diabetes mellitus type-2 and stage-2 chronic kidney disease secondary to diabetic nephropathy presented with an acute deterioration of kidney function. Non-invasive work-up failed to reveal the underlying aetiology for the acute kidney failure. Kidney biopsy revealed acute tubulointerstitial nephritis (ATIN) which was attributed to sitagliptin use. Only few case reports have shown this correlation. Our aim is to alert physicians and other providers of the potential effect of sitagliptin to cause ATIN with this biopsy-proven case.
Determinants of regular smoking onset in South Africa using duration analysis
Authors: Vellios Nicole , van Walbeek Corné
Published: July 2016

Objectives

South Africa has achieved significant success with its tobacco control policy. Between 1994 and 2012, the real price of cigarettes increased by 229%, while regular smoking prevalence decreased from about 31% to 18.2%.

Methods

Cigarette prices and socioeconomic variables are used to examine the determinants of regular smoking onset. We apply duration analysis techniques to the National Income Dynamics Study, a nationally representative survey of South Africa.

Results

We find that an increase in cigarette prices significantly reduces regular smoking initiation among males, but not among females. Regular smoking among parents is positively correlated with smoking initiation among children. Children with more educated parents are less likely to initiate regular smoking than those with less educated parents. Africans initiate later and at lower rates than other race groups.

Conclusions

As the tobacco epidemic is shifting towards low-income and middle-income countries, there is an increasing urgency to perform studies in these countries to influence policy. Higher cigarette excise taxes, which lead to higher retail prices, reduce smoking prevalence by encouraging smokers to quit and by discouraging young people from starting smoking.