bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of extrinsic cardiac nerve stimulation on atrial fibrillation inducibility: The regulatory role of the spinal cord
Authors: Dai Zixuan , Huang Congxin , Zhao Qingyan , Zhang Shujuan , Zhao Hongyi , Zhang Youjing , Qian Yongsheng , Tang Yanhong
Published: April 2017

Objective

To investigate the effect of the mutual regulation of the extrinsic cardiac nerves on atrial electrophysiology and atrial fibrillation (AF) vulnerability.

Methods and results

Fourteen dogs were randomly divided into two groups: spinal cord stimulation (SCS) group (n = 7) and spinal cord block (SCB) group (n = 7). SCS was performed with 90% of the threshold voltage stimulating the T1–T2 spinal level, while SCB was performed by injecting 2% lidocaine into the epidural space at the T2–3 level. The effective refractory period (ERP), ERP dispersion, and AF inducibility were measured during atrial pacing combined with different extrinsic cardiac nerve stimulation. ERPs were decreased in the atrium and pulmonary veins and ERP dispersion was increased from baseline during left cervical vagus nerve stimulation (VNS) or left stellate ganglion stimulation (SGS) in the two groups. When combined with SCS, VNS resulted in diminished ERPs at all recording sites, longer ERP dispersion and more episodes of AF than were observed during VNS, whereas ERPs were greater and correspondingly fewer episodes of AF occurred during SCS combined with SGS than SGS. In the SCB group, ERPs were shortened, ERP dispersion was lengthened, and episodes of AF were increased during SGS after SCB. SCS enhanced the activity of the left vagus nerve but attenuated the left stellate ganglion and superior left ganglionated plexus.

Conclusion

SCS modulates extrinsic and intrinsic cardiac nerve activity among the vagus nerve, stellate ganglion, and ganglionated plexus. SCS facilitates the effect of VNS and attenuates the effect of SGS on atrial electrophysiology.
miR‐495 sensitizes MDR cancer cells to the combination of doxorubicin and taxol by inhibiting MDR1 expression
Authors: Zou Zhenyou , Zou Ruyi , Zong Dan , Shi Yonghong , Chen Jinyao , Huang Jie , Zhu Jiahui , Chen Liguan , Bao Xiaoyan , Liu Yuan , Liu Weihao , Huang Wenhui , Hu Jingsang , Chen Zhi , Lao Xiaojie , Chen Chaoqun , Huang Xiaoli , Lu Yao , Ni Xueyin , Fang Daoquan , Wu Dengqiang , Lu Shuangshuang , Jiang Mingzhu , Qiu Chenyang , Wu Yuya , Qiu Qisha , Dong Yanyuan , Su Yangyang , Zhao Chenmin , Zhong Zhihe , Cai Jing , Liang Yong
Published: April 2017

MDR1 is highly expressed in MDR A2780DX5 ovarian cancer cells, MDR SGC7901R gastric cancer cells and recurrent tumours. It pumps cytoplasmic agents out of cells, leading to decreased drug accumulation in cells and making cancer cells susceptible to multidrug resistance. Here, we identified that miR‐495 was predicted to target ABCB1, which encodes protein MDR1. To reduce the drug efflux and reverse MDR in cancer cells, we overexpressed a miR‐495 mimic in SGC7901R and A2780DX cells and in transplanted MDR ovarian tumours in vivo. The results indicated that the expression of MDR1 in the above cells or tumours was suppressed and that subsequently the drug accumulation in the MDR cells was decreased, cell death was increased, and tumour growth was inhibited after treatment with taxol‐doxorubicin, demonstrating increased drug sensitivity. This study suggests that pre‐treatment with miR‐495 before chemotherapy could improve the curative effect on MDR1‐based MDR cancer.
The impact of dung on inter‐ and intraspecific competition of temperate grassland seeds
Authors: Milotić Tanja , Hoffmann Maurice
Published: April 2017

Questions

In temperate grasslands, seeds of numerous dry‐fruited plant species are dispersed via ingestion and subsequent defecation by grazing animals. Depending on the herbivore species and season, dung pats may contain a large assemblage of conspecific or heterospecific seeds competing for space, light and nutrients in the space‐limited environment of an individual dung pat. In an environment rich in nutrients, such as herbivore dung, the outcome of inter‐ and intraspecific competition might differ from situations where nutrients are limiting. Additionally, dung pats being small and spatially isolated habitats with very specific conditions may also impact competitive interactions. Besides the plant–soil interactions on competition known from literature, the specific quality and structure of dung pats might provoke more complex interactions between different seed densities and species combinations.

Methods

We conducted a greenhouse competition experiment using three common perennial grassland species. Agrostis stolonifera, Trifolium pratense and Trifolium repens were used in two‐species combinations with different proportions of each species and in monocultures. Seeds were sown in three seed densities (50, 150 and 250 seeds) and the effects of cattle and horse dung on establishment, growth and flowering were tested.

Results

Interactions, most probably attributable to interspecific competition, differed between species mixtures. Seeds sown in polycultures generally emerged sooner, but the resulting seedlings had lower relative growth rates compared with seeds sown in monocultures. Increased biomass was measured for each species when growing in polycultures while evidence for intraspecific competition was found in monocultures. T. pratense developed relatively more flowers when plants were growing in polycultures compared with monocultures. Few effects of seed densities were found, although higher seed densities led to lower establishment success in both monocultures and polycultures. Adding dung generally increased the time needed to emerge, relative growth rates and flowering, but decreased establishment success in monocultures.

Conclusions

Both seed density and the presence of dung shape the post‐dispersal fate of seeds. While high seed densities imply a cost due to lower germinability, the nutritive environment of dung acts as compensation, resulting in faster growth and an increased investment in reproductive tissues.
Transcriptomics of cereal–Fusarium graminearum interactions: what we have learned so far
Authors: Kazan Kemal , Gardiner Donald M.
Published: April 2017

The ascomycete fungal pathogen Fusarium graminearum causes the globally important Fusarium head blight (FHB) disease on cereal hosts, such as wheat and barley. In addition to reducing grain yield, infection by this pathogen causes major quality losses. In particular, the contamination of food and feed with the F. graminearum trichothecene toxin deoxynivalenol (DON) can have many adverse short‐ and long‐term effects on human and animal health. During the last decade, the interaction between F. graminearum and both cereal and model hosts has been extensively studied through transcriptomic analyses. In this review, we present an overview of how such analyses have advanced our understanding of this economically important plant–microbe interaction. From a host point of view, the transcriptomes of FHB‐resistant and FHB‐susceptible cereal genotypes, including near‐isogenic lines (NILs) that differ by the presence or absence of quantitative trait loci (QTLs), have been studied to understand the mechanisms of disease resistance afforded by such QTLs. Transcriptomic analyses employed to dissect host responses to DON have facilitated the identification of the genes involved in toxin detoxification and disease resistance. From the pathogen point of view, the transcriptome of F. graminearum during pathogenic vs. saprophytic growth, or when infecting different cereal hosts or different tissues of the same host, have been studied. In addition, comparative transcriptomic analyses of F. graminearum knock‐out mutants with altered virulence have provided new insights into pathogenicity‐related processes. The F. graminearum transcriptomic data generated over the years are now being exploited to build a systems level understanding of the biology of this pathogen, with an ultimate aim of developing effective and sustainable disease prevention strategies.
Permethrin and malathion LD90 values for Culex quinquefasciatus vary with topical application site
Authors: ALDRIDGE R. L. , KAUFMAN P. E. , BLOOMQUIST J. R. , GEZAN S. A. , LINTHICUM K. J.
Published: April 2017

Prior research in multiple insect species has demonstrated that insecticide‐induced mortality varies according to the body region exposed on the insect. This variation has been demonstrated in Culex quinquefasciatus Say (Diptera: Culicidae), but has not been quantified using dose–response curves. Applications of technical permethrin or malathion to one of three body regions on Cx. quinquefasciatus resulted in dose–response curves that were not equivalent to one another. The generated LD90 values and curves for each body region were compared with previously reported LD values for analogous sites in several mosquito species, specifically the mesothorax. Based on the present results, the permethrin and malathion LD50 and LD90 concentrations required for droplets impinging on the abdomen and mesothorax of Cx. quinquefasciatus when applied through ground‐based spray systems utilized by mosquito control programmes were calculated.
The Good, the Bad, and the Transitivity of Better Than*
Authors: Nebel Jacob M.
Published: April 2017

The Rachels–Temkin spectrum arguments against the transitivity of better than involve good or bad experiences, lives, or outcomes that vary along multiple dimensions—e.g., duration and intensity of pleasure or pain. This paper presents variations on these arguments involving combinations of good and bad experiences, which have even more radical implications than the violation of transitivity. These variations force opponents of transitivity to conclude that something good is worse than something that isn't good, on pain of rejecting the good altogether. That is impossible, so we must reject the spectrum arguments.
Risk Factors Associated with Pain on Chronic Intermittent Hemodialysis: A Systematic Review
Authors: Brkovic Tonci , Burilovic Eliana , Puljak Livia
Published: April 2017

Objectives

The aim of the study was to define risk factors related to pain in adult end‐stage renal disease (ESRD) patients on chronic intermittent hemodialysis (HD) by developing a systematic review of published data.

Methods

The search was conducted from MEDLINE, Scopus, PsycINFO, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). Manuscripts in all languages were considered. Two authors performed each step independently, and all disagreements were resolved after discussion with the third author. Quality of studies was analyzed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist and Cochrane risk of bias tool.

Results

A total of 67 studies with 7,818 participants were included (median number of participants = 60). Most of the studies reported common factors such as age, gender, body mass index, race/ethnicity, marital status, duration of HD treatment since initiation of HD, different comorbidities, and biochemical parameters. Other studies reported more specific factors such as type, regimen or place of hemodialysis, type of dialyzer, dialysis phase, type of dialyzer membrane, administration site, type of preparation, and dose of erythropoiesis‐stimulating agent (ESA). The studies indicate that these factors may contribute to increased pain in general and also promote development of different pain modalities of various locations and causes in HD patients (eg, pain in general, pain related to arteriovenous access, headache, musculoskeletal pain, ESA application pain).

Discussion

Multiple factors for various types of pain in very heterogeneous populations and heterogeneous settings were analyzed in the literature. The results turned out to be inconsistent between the studies. Future large‐scale studies are required, taking into the account limitations of the current evidence base.
The surprising upsides of worry
Authors: Sweeny Kate , Dooley Michael D.
Published: April 2017

Worry is an aversive emotional experience that arises alongside repetitive unpleasant thoughts about the future. In this paper, we argue that although extreme levels of worry are associated with depressed mood, poor physical health, and even mental illness, worry has an upside. We focus on two empirically supported benefits of worry: its motivational benefits and its benefit as an emotional buffer. Regarding motivation, worry illuminates the importance of taking action to prevent an undesirable outcome and keeps the situation at the front of one's mind to ensure that appropriate action is taken. It also triggers efforts to mitigate the consequences of bad news, motivates productive behavior that in turn reduces worry, and enhances the effectiveness of goal‐directed action by prompting people to focus on obstacles that might derail best‐laid plans. Worry can also serve as an emotional buffer by providing a desirable contrast to subsequent affective reactions, particularly for people who are prone to high levels of worry.
Unbiased Technique in Identifying Appropriate Variables for FDI Inflows Model: A Role of Economic Growth in SADC
Authors: Njoku Chidozie , Chiwira Oscar
Published: April 2017

This paper recommends an unbiased technique in choosing appropriate variables for FDI inflows in SADC member states by using a modified TYDL causality test. The results have proven 100% accuracy with this technique by identifying economic growth, domestic investment, government size, import openness, balance of payment and dummy for SADC integration as significant factors that influence FDI inflows in SADC. In addition, all the diagnostic tests are conducted to ensure that this approach is not biased. Furthermore, economic growth, domestic investment, government size, import openness and dummy for SADC integration have positive significant effect on FDI inflows in SADC while balance of payment has a negative significant effect on FDI inflows in SADC. This paper recommends that researchers should understand difference in countries and regions as they consider variables in their modelling. The negligence of this differences result to policies contradictions and hence lend to policy makers adopting a discretionary policy. This type of policy in a long-run may distorts the intended goals and thereby making the economy of the country(s) potentially worst off in the long-run.
Investigation on deep level defects in polycrystalline ZnO thin films
Authors: Tsiarapas Christos , Girginoudi Dimitra , Dimitriadis Evangelos Ioannou , Georgoulas Nikolaos
Published: April 2017

Deep level traps detection and characterization in polycrystalline ZnO thin films have been investigated by deep level transient spectroscopy (DLTS) on Pd/ZnO Schottky contacts. Τhe influence of different amounts of incorporated hydrogen in ZnO layers on the creation and evolution of these traps has been studied as well. The films were deposited on n-Si substrates with direct current-sputtering, varying the hydrogen, H, flow rate in the Ar/H sputtering gas, so that the H per volume concentration [H2] was 0%, 20%, 33.3%, 50%, and 66.6%. The Pd/ZnO contacts are more stable and reliable for DLTS characterization than the respective Au/ZnO ones. Four deep electron traps were detected in all samples, referred to as traps A, B, C, and D, with respective activation energies of 0.30, 0.21, 0.47, and 0.54 eV. Another trap, E (0.61 eV), was found in the 50% and 66.6% H2 samples. Traps A and B, which are commonly observed in ZnO, are related to intrinsic defects. Trap C is attributed to surface defects, while trap D may be an extended defect that contains oxygen vacancies. Broad trap E is connected to extended defects. The defects' concentration is higher as the DLTS space-charge region extends closer to the surface. The incorporated hydrogen not only behaves differently depending on the H2 flow rate, but also seems to interact with traps, as it causes a significant reduction in A and B traps' concentrations for [H2] ≤ 33.3%, probably due to the formation of H-VO complexes, and an increase in the other traps' concentrations, in which H participates in, or at least favors their formation for [H2] > 33.3%.
Study of tungsten films deposited by DC sputtering dedicated to integrated heaters
Authors: Verbrugghe Nathalie , Fasquelle Didier , Duponchel Benoît , Députier Stéphanie
Published: April 2017

In order to realize cost-effective semiconductor gas sensors, the authors have studied the feasibility of replacing platinum by tungsten for the metallic layer of heaters in a moderate temperature range (25–400 °C). Tungsten films were deposited on silicon substrates by direct current magnetron sputtering in argon gas. The deposition of tungsten films was investigated at various working gas pressures to modify the microstructure. The results have shown that low-stressed films showed a good adhesion to silicon substrates. Resistivity values as low as 27 μΩ cm were obtained for 600 nm films deposited at low argon pressure. After a thermal treatment at 500 °C for 30 min., no resistivity variation occurred for films deposited at low argon pressure. Finally, three different structures of tungsten heaters were elaborated by using an optical lithography technique and tested for 300 h at 400 °C.
Extending the bandwidth of an acoustic beamforming array using phase unwrapping and array interpolation
Authors: Goates Caleb B. , Harker Blaine M. , Neilsen Tracianne B. , Gee Kent L.
Published: April 2017

A method is presented to suppress grating lobes in beamforming using phase unwrapping and array interpolation. When the phase of each cross spectrum is successfully unwrapped, the magnitude and phase of the cross spectral matrix may be interpolated; for cases where these quantities vary smoothly, interpolation is straightforward, even above the spatial Nyquist frequency. Two applications are presented: localization of a broadband source and characterization of a source with frequency-dependent location. In both cases, grating lobes are suppressed and the source is localized at frequencies up to at least 8 times the spatial Nyquist frequency.
Underwater Treadmill Training for a Greenstick Fracture in a Collegiate Softball Player: A Case Report
Authors: Harrison Layci J. , Young Kala L. , Stevens Sandra L. , Caputo Jennifer L.
Published: April 2017

A 19-year-old collegiate softball player collided with a fence while trying to catch a fly ball, resulting in a greenstick fibular fracture. Underwater treadmill training (UTT) was used as a modality to supplement traditional physical therapy (TPT). Active range of motion (AROM) in all directions for the knee, hip, and ankle, girth of the thigh and lower leg, static balance, and 6-Minute Walk Test (6MWT) distance were assessed pre- and postintervention. The addition of UTT to TPT led to postintervention increases in AROM, static balance, and limb girth, with no additional discomfort to the participant.
The Effect of Nitrate Supplementation on Cycling Performance in the Heat in Well-Trained Cyclists
Authors: McQuillan Joseph A. , Casadio Julia R. , Dulson Deborah K. , Laursen Paul B. , Kilding Andrew E.
Published: April 2017

Purpose: To determine the effect of consumption on measures of perception, thermoregulation, and cycling performance in hot conditions. Methods: In a randomized, double-blind, crossover design, 8 well-trained cyclists (mean ± SD age 25 ± 8 y, peak 64 ± 5 mL · kg−1 · min−1) performed 2 separate trials in hot (35°C, 60% relative humidity) environments, having ingested either 140 mL -rich beetroot juice ∼8 mmol (NIT) or placebo (PLA) daily for 3 d with a 7-d washout period separating trials. Trials consisted of 2 × 10-min bouts at 40% and 60% peak power output (PPO) to determine physiological and perceptual responses to the heat, followed by a 4-km cycling time trial. Results: Basal [nitrite] was substantially elevated in NIT (2.70 ± 0.98 µM) vs PLA (1.10 ± 0.61 µM), resulting in a most likely (ES = 1.58 ± 0.93) increase after 3 d. There was a very likely trivial increase in rectal temperature in NIT at 40% (PLA 37.4°C ± 0.2°C vs NIT 37.5°C ± 0.3°C, 0.1°C ± 0.2°C) and 60% (PLA 37.8°C ± 0.2°C vs NIT 37.9°C ± 0.3°C, 0.1°C ± 0.2°C) PPO. Cycling performance was similar between trials (PLA 336 ± 45 W vs NIT 337 ± 50 W, CV ± 95%CL; 0.2% ± 2.5%). Outcomes for heart rate and perceptual measures were unclear across the majority of time points. Conclusions: Three days of supplementation resulted in small increases in rectal temperature during low- to moderate-intensity exercise, but this did not appear to influence 4-km cycling time-trial performance in hot climates.
The Acute Effects of Breaking Up Seated Office Work With Standing or Light-Intensity Walking on Interstitial Glucose Concentration: A Randomized Crossover Trial
Authors: Brocklebank Laura A. , Andrews Rob C. , Page Angie , Falconer Catherine L. , Leary Sam , Cooper Ashley
Published: April 2017

Background:

The aim of this randomized, 3-period, 3-treatment crossover trial was to examine the acute effects of regularly breaking up seated office work with short bouts of standing or light-intensity walking on postprandial interstitial glucose concentration.

Methods:

Seventeen middle-aged office workers performed 3 5-hour trial conditions at their workplace in a random order: 1) uninterrupted sitting, 2) sitting interrupted by 2 minutes of standing every 20 minutes, and 3) sitting interrupted by 2 minutes of light-intensity walking every 20 minutes. Participants consumed 2 standardized test drinks at the start of each trial condition and an iPro2 continuous glucose monitoring system (CGMS) recorded average interstitial glucose concentration every 5 minutes for the duration of the study.

Results:

The 5-hour interstitial glucose incremental area under the curve (iAUC) was 55.5% lower after sitting interrupted by light-intensity walking compared with after uninterrupted sitting (95% CI, –104.2% to –6.8%). There was also a suggestion of a beneficial effect of regular standing breaks, particularly in overweight men, although they were not as effective as the walking breaks (mean difference [95% CI], –29.6% [–73.9% to 14.7%]).

Conclusions:

Regularly breaking up prolonged sitting lowers postprandial glycemia in middle-aged adults without metabolic impairment.
Imaging the dark emission of spasers
Authors: Chen Hua-Zhou , Hu Jia-Qi , Wang Suo , Li Bo , Wang Xing-Yuan , Wang Yi-Lun , Dai Lun , Ma Ren-Min
Published: April 2017

Spasers can serve as a pure surface plasmon generator with a coupling efficiency to plasmonic modes approaching 100%.
Potential energy–driven spin manipulation via a controllable hydrogen ligand
Authors: Jacobson Peter , Muenks Matthias , Laskin Gennadii , Brovko Oleg , Stepanyuk Valeri , Ternes Markus , Kern Klaus
Published: April 2017

A hydrogen-functionalized scanning probe tip is used to reversibly switch the total spin of a cobalt hydride complex.
CH
3
NH
3
PbI
3
perovskites: Ferroelasticity revealed
Authors: Strelcov Evgheni , Dong Qingfeng , Li Tao , Chae Jungseok , Shao Yuchuan , Deng Yehao , Gruverman Alexei , Huang Jinsong , Centrone Andrea
Published: April 2017

Evidence and control of ferroelastic (but not ferroelectric) domains in CH
3
NH
3
PbI
3
perovskite are provided.
Accelerated discovery of new magnets in the Heusler alloy family
Authors: Sanvito Stefano , Oses Corey , Xue Junkai , Tiwari Anurag , Zic Mario , Archer Thomas , Tozman Pelin , Venkatesan Munuswamy , Coey Michael , Curtarolo Stefano
Published: April 2017

Advanced computer simulations and database access enable the design of novel magnetic materials at an unprecedented speed.
Observation of current-induced, long-lived persistent spin polarization in a topological insulator: A rechargeable spin battery
Authors: Tian Jifa , Hong Seokmin , Miotkowski Ireneusz , Datta Supriyo , Chen Yong P.
Published: April 2017

We report a current-induced, persistent, long-lived, and rewritable electron spin polarization in a 3D topological insulator.
SAVI: Synthetic apertures for long-range, subdiffraction-limited visible imaging using Fourier ptychography
Authors: Holloway Jason , Wu Yicheng , Sharma Manoj K. , Cossairt Oliver , Veeraraghavan Ashok
Published: April 2017

Synthetic apertures for visible imaging are a promising approach to achieving subdiffraction resolution in long-distance imaging.
Single-layer nanosheets with exceptionally high and anisotropic hydroxyl ion conductivity
Authors: Sun Pengzhan , Ma Renzhi , Bai Xueyin , Wang Kunlin , Zhu Hongwei , Sasaki Takayoshi
Published: April 2017

Nanosheets exhibit high and anisotropic hydroxyl ion conductivity, promising potentials in energy or environment applications.
Mechanism of Vps4 hexamer function revealed by cryo-EM
Authors: Su Min , Guo Emily Z. , Ding Xinqiang , Li Yan , Tarrasch Jeffrey T. , Brooks Charles L. , Xu Zhaohui , Skiniotis Georgios
Published: April 2017

Cryo-EM structures illustrate a novel mechanism for Vps4-mediated disassembly of ESCRT-III filaments.
Synovial fibroblast-neutrophil interactions promote pathogenic adaptive immunity in rheumatoid arthritis
Authors: Carmona-Rivera Carmelo , Carlucci Philip M. , Moore Erica , Lingampalli Nithya , Uchtenhagen Hannes , James Eddie , Liu Yudong , Bicker Kevin L. , Wahamaa Heidi , Hoffmann Victoria , Catrina Anca Irinel , Thompson Paul R. , Buckner Jane H. , Robinson William H. , Fox David A. , Kaplan Mariana J.
Published: April 2017

Neutrophil extracellular traps containing citrullinated peptides promote inflammation in synovial fibroblasts.
Resident memory T cells in the skin mediate durable immunity to melanoma
Authors: Malik Brian T. , Byrne Katelyn T. , Vella Jennifer L. , Zhang Peisheng , Shabaneh Tamer B. , Steinberg Shannon M. , Molodtsov Aleksey K. , Bowers Jacob S. , Angeles Christina V. , Paulos Chrystal M. , Huang Yina H. , Turk Mary Jo
Published: April 2017

Resident memory CD8 T cells maintained in vitiligo-affected skin mediate long-lived protection against melanoma.
Toward off-the-shelf adoptive T cell therapies
Authors: Chung Kwanghun
Published: April 2017

Artificial thymic organoids may enable more efficient engineered T cell production for immunotherapy.
Comparison of EUCAST and CLSI Reference Microdilution MICs of Eight Antifungal Compounds for Candida auris and Associated Tentative Epidemiological Cutoff Values
Authors: Arendrup M. C. , Prakash Anupam , Meletiadis Joseph , Sharma Cheshta , Chowdhary Anuradha
Published: April 2017

Candida auris
is an emerging multidrug-resistant yeast. So far, all but two susceptibility testing studies have examined ≤50 isolates, mostly with the CLSI method. We investigated CLSI and EUCAST MICs for 123
C. auris
isolates and eight antifungals and evaluated various methods for epidemiological cutoff (ECOFF) determinations. MICs (in milligrams per liter) were determined using CLSI method M27-A3, and the EUCAST E.Def 7.3. ANOVA analysis of variance with Bonferroni's multiple-comparison test and Pearson analysis were used on log
2
MICs (significance at
P
values of <0.05). The percent agreement (within ±0 to ±2 2-fold dilutions) between the methods was calculated. ECOFFs were determined visually, statistically (using the ECOFF Finder program and MicDat1.23 software with 95% to 99% endpoints), and via the derivatization method (dECOFFs). The CLSI and EUCAST MIC distributions were wide, with several peaks for all compounds except amphotericin B, suggesting possible acquired resistance. Modal MIC, geometric MIC, MIC
50
, and MIC
90
values were ≤1 2-fold dilutions apart, and no significant differences were found. The quantitative agreement was best for amphotericin B (80%/97% within ±1/±2 dilutions) and lowest for isavuconazole and anidulafungin (58%/76% to 75% within ±1/±2 dilutions). We found that 90.2%/100% of the isolates were amphotericin B susceptible based on CLSI/EUCAST methods, respectively (i.e., with MICs of ≤1 mg/liter), and 100%/97.6% were fluconazole nonsusceptible by CLSI/EUCAST (MICs > 2). The ECOFFs (in milligrams per liter) were similar across the three different methods for itraconazole (ranges for CLSI/EUCAST, 0.25 to 0.5/0.5 to 1), posaconazole (0.125/0.125 to 0.25), amphotericin B (0.25 to 0.5/1 to 2), micafungin (0.25 to 0.5), and anidulafungin (0.25 to 0.5/0.25 to 1). In contrast, the estimated ECOFFs were dependent on the method applied for voriconazole (1 to 32) and isavuconazole (0.125 to 4). CLSI and EUCAST MICs were remarkably similar and confirmed uniform fluconazole resistance and variable acquired resistance to the other agents.
A Genome-Wide Search for Ionizing-Radiation-Responsive Elements in Deinococcus radiodurans Reveals a Regulatory Role for the DNA Gyrase Subunit A Gene's 5′ Untranslated Region in the Radiation and Desiccation Response
Authors: Villa Jordan K. , Amador Paul , Janovsky Justin , Bhuyan Arijit , Saldanha Roland , Lamkin Thomas J. , Contreras Lydia M.
Published: April 2017

Tight regulation of gene expression is important for the survival of
Deinococcus radiodurans
, a model bacterium of extreme stress resistance. Few studies have examined the use of regulatory RNAs as a possible contributing mechanism to ionizing radiation (IR) resistance, despite their proffered efficient and dynamic gene expression regulation under IR stress. This work presents a transcriptome-based approach for the identification of stress-responsive regulatory 5′ untranslated region (5′-UTR) elements in
D. radiodurans
R1 that can be broadly applied to other bacteria. Using this platform and an
in vivo
fluorescence screen, we uncovered the presence of a radiation-responsive regulatory motif in the 5′ UTR of the DNA gyrase subunit A gene. Additional screens under H
2
O
2
-induced oxidative stress revealed the specificity of the response of this element to IR stress. Further examination of the sequence revealed a regulatory motif of the radiation and desiccation response (RDR) in the 5′ UTR that is necessary for the recovery of
D. radiodurans
from high doses of IR. Furthermore, we suggest that it is the preservation of predicted RNA structure, in addition to DNA sequence consensus of the motif, that permits this important regulatory ability.

IMPORTANCE
Deinococcus radiodurans
is an extremely stress-resistant bacterium capable of tolerating up to 3,000 times more ionizing radiation than human cells. As an integral part of the stress response mechanism of this organism, we suspect that it maintains stringent control of gene expression. However, understanding of its regulatory pathways remains incomplete to date. Untranslated RNA elements have been demonstrated to play crucial roles in gene regulation throughout bacteria. In this work, we focus on searching for and characterizing responsive RNA elements under radiation stress and propose that multiple levels of gene regulation work simultaneously to enable this organism to efficiently recover from exposure to ionizing radiation. The model we propose serves as a generic template to investigate similar mechanisms of gene regulation under stress that have likely evolved in other bacterial species.
The Global Transcription Factor Lrp Is both Essential for and Inhibitory to Xenorhabdus nematophila Insecticidal Activity
Authors: Casanova-Torres Ángel M. , Shokal Upasana , Morag Neta , Eleftherianos Ioannis , Goodrich-Blair Heidi
Published: April 2017

In the entomopathogenic bacterium
Xenorhabdus nematophila
, cell-to-cell variation in the abundance of the Lrp transcription factor leads to virulence modulation; low Lrp levels are associated with a virulent phenotype and suppression of antimicrobial peptides (AMPs) in
Manduca sexta
insects, while cells that lack
lrp
or express high Lrp levels are virulence attenuated and elicit AMP expression. To better understand the basis of these phenotypes, we examined
X. nematophila
strains expressing fixed Lrp levels. Unlike the
lrp
-null mutant, the high-
lrp
strain is fully virulent in
Drosophila melanogaster
, suggesting that these two strains have distinct underlying causes of virulence attenuation in
M. sexta
. Indeed, the
lrp
-null mutant was defective in cytotoxicity against
M. sexta
hemocytes relative to that in the high-
lrp
and low-
lrp
strains. Further, supernatant derived from the
lrp
-null mutant but not from the high-
lrp
strain was defective in inhibiting weight gain when fed to 1st instar
M. sexta
. These data suggest that contributors to the
lrp
-null mutant virulence attenuation phenotype are the lack of Lrp-dependent cytotoxic and extracellular oral growth inhibitory activities, which may be particularly important for virulence in
D. melanogaster
. In contrast, the high-Lrp strain was sensitive to the antimicrobial peptide cecropin, had a transient survival defect in
M. sexta
, and had reduced extracellular levels of insecticidal activity, measured by injection of supernatant into 4th instar
M. sexta
. Thus, high-
lrp
strain virulence attenuation may be explained by its hypersensitivity to
M. sexta
host immunity and its inability to secrete one or more insecticidal factors.

IMPORTANCE
Adaptation of a bacterial pathogen to host environments can be achieved through the coordinated regulation of virulence factors that can optimize success under prevailing conditions. In the insect pathogen
Xenorhabdus nematophila
, the global transcription factor Lrp is necessary for virulence when injected into
Manduca sexta
or
Drosophila melanogaster
insect hosts. However, high levels of Lrp, either naturally occurring or artificially induced, cause attenuation of
X. nematophila
virulence in
M. sexta
but not
D. melanogaster
. Here, we present evidence suggesting that the underlying cause of high-Lrp-dependent virulence attenuation in
M. sexta
is hypersensitivity to host immune responses and decreased insecticidal activity and that high-Lrp virulence phenotypes are insect host specific. This knowledge suggests that
X. nematophila
faces varied challenges depending on the type of insect host it infects and that its success in these environments depends on Lrp-dependent control of a multifactorial virulence repertoire.
The Conjugative Relaxase TrwC Promotes Integration of Foreign DNA in the Human Genome
Authors: González-Prieto Coral , Gabriel Richard , Dehio Christoph , Schmidt Manfred , Llosa Matxalen
Published: April 2017

Bacterial conjugation is a mechanism of horizontal DNA transfer. The relaxase TrwC of the conjugative plasmid R388 cleaves one strand of the transferred DNA at the
oriT
gene, covalently attaches to it, and leads the single-stranded DNA (ssDNA) into the recipient cell. In addition, TrwC catalyzes site-specific integration of the transferred DNA into its target sequence present in the genome of the recipient bacterium. Here, we report the analysis of the efficiency and specificity of the integrase activity of TrwC in human cells, using the type IV secretion system of the human pathogen
Bartonella henselae
to introduce relaxase-DNA complexes. Compared to Mob relaxase from plasmid pBGR1, we found that TrwC mediated a 10-fold increase in the rate of plasmid DNA transfer to human cells and a 100-fold increase in the rate of chromosomal integration of the transferred DNA. We used linear amplification-mediated PCR and plasmid rescue to characterize the integration pattern in the human genome. DNA sequence analysis revealed mostly reconstituted
oriT
sequences, indicating that TrwC is active and recircularizes transferred DNA in human cells. One TrwC-mediated site-specific integration event was detected, proving that TrwC is capable of mediating site-specific integration in the human genome, albeit with very low efficiency compared to the rate of random integration. Our results suggest that TrwC may stabilize the plasmid DNA molecules in the nucleus of the human cell, probably by recircularization of the transferred DNA strand. This stabilization would increase the opportunities for integration of the DNA by the host machinery.

IMPORTANCE
Different biotechnological applications, including gene therapy strategies, require permanent modification of target cells. Long-term expression is achieved either by extrachromosomal persistence or by integration of the introduced DNA. Here, we studied the utility of conjugative relaxase TrwC, a bacterial protein with site-specific integrase activity in bacteria, as an integrase in human cells. Although it is not efficient as a site-specific integrase, we found that TrwC is active in human cells and promotes random integration of the transferred DNA in the human genome, probably acting as a DNA chaperone until it is integrated by host mechanisms. TrwC-DNA complexes can be delivered to human cells through a type IV secretion system involved in pathogenesis. Thus, TrwC could be used
in vivo
to transfer the DNA of interest into the appropriate cell and promote its integration. If used in combination with a site-specific nuclease, it could lead to site-specific integration of the incoming DNA by homologous recombination.
Construction of a Gene Knockdown System Based on Catalytically Inactive (“Dead”) Cas9 (dCas9) in Staphylococcus aureus
Authors: Zhao Changlong , Shu Xueqin , Sun Baolin
Published: April 2017

There has been an absence of an efficient method of gene knockdown in the important human pathogen
Staphylococcus aureus
like RNA interference in eukaryotes. The previously developed antisense RNA technology is mainly applied for forward genetic screening but is rather limited in specific gene knockdown because of the lack of rational antisense RNA design strategies. Here we report an efficient and specific system for gene knockdown in
S. aureus
based on the type II clustered regularly interspaced short palindromic repeat (CRISPR) system from
Streptococcus pyogenes
. We can achieve gene silencing with the coexpression of dCas9, an RNA-guided DNA binding protein, and a small guide RNA complementary to the target gene. With this system, we have successfully silenced diverse sets of genes varying in size and expression level in different
S. aureus
strains. This system exhibited high-efficiency knockdown of both essential and nonessential genes, and its effect is inducible and reversible. In addition, the system can repress the expression of multiple genes simultaneously and silence an entire operon or part of it. This RNA-guided DNA targeting system thus provides a simple, rapid, and affordable method for selective gene knockdown in
S. aureus
.

IMPORTANCE
Staphylococcus aureus
is an important human and animal pathogen that can cause a diversity of infectious diseases. Molecular genetic study of
S. aureus
has provided an avenue for the understanding of its virulence, pathogenesis, and drug resistance, leading to the discovery of new therapies for the treatment of staphylococcal infections. However, methodologies developed for genetic manipulation of
S. aureus
usually involve either low efficiency or laborious procedures. Here we report an RNA-guided system for gene knockdown in
S. aureus
and show its high efficiency and simplicity for selective gene silencing in different strains of
S. aureus
. This simple, rapid, and affordable system may serve as a promising tool for functional gene study in
S. aureus
, especially for the study of essential genes, thus facilitating the understanding of this pathogen and its interaction with its hosts.
An Extracellular Cell-Attached Pullulanase Confers Branched α-Glucan Utilization in Human Gut Lactobacillus acidophilus
Authors: Møller Marie S. , Goh Yong Jun , Rasmussen Kasper Bøwig , Cypryk Wojciech , Celebioglu Hasan Ufuk , Klaenhammer Todd R. , Svensson Birte , Abou Hachem Maher
Published: April 2017

Of the few predicted extracellular glycan-active enzymes, glycoside hydrolase family 13 subfamily 14 (GH13_14) pullulanases are the most common in human gut lactobacilli. These enzymes share a unique modular organization, not observed in other bacteria, featuring a catalytic module, two starch binding modules, a domain of unknown function, and a C-terminal surface layer association protein (SLAP) domain. Here, we explore the specificity of a representative of this group of pullulanases,
Lactobacillus acidophilus
Pul13_14 (
La
Pul13_14), and its role in branched α-glucan metabolism in the well-characterized
Lactobacillus acidophilus
NCFM, which is widely used as a probiotic. Growth experiments with
L. acidophilus
NCFM on starch-derived branched substrates revealed a preference for α-glucans with short branches of about two to three glucosyl moieties over amylopectin with longer branches. Cell-attached debranching activity was measurable in the presence of α-glucans but was repressed by glucose. The debranching activity is conferred exclusively by
La
Pul13_14 and is abolished in a mutant strain lacking a functional
La
Pul13_14 gene. Hydrolysis kinetics of recombinant
La
Pul13_14 confirmed the preference for short-branched α-glucan oligomers consistent with the growth data. Curiously, this enzyme displayed the highest catalytic efficiency and the lowest

K
m

reported for a pullulanase. Inhibition kinetics revealed mixed inhibition by β-cyclodextrin, suggesting the presence of additional glucan binding sites besides the active site of the enzyme, which may contribute to the unprecedented substrate affinity. The enzyme also displays high thermostability and higher activity in the acidic pH range, reflecting adaptation to the physiologically challenging conditions in the human gut.

IMPORTANCE
Starch is one of the most abundant glycans in the human diet. Branched α-1,6-glucans in dietary starch and glycogen are nondegradable by human enzymes and constitute a metabolic resource for the gut microbiota. The role of health-beneficial lactobacilli prevalent in the human small intestine in starch metabolism remains unexplored in contrast to colonic bacterial residents. This study highlights the pivotal role of debranching enzymes in the breakdown of starchy branched α-glucan oligomers (α-limit dextrins) by human gut lactobacilli exemplified by
Lactobacillus acidophilus
NCFM, which is one of the best-characterized strains used as probiotics. Our data bring novel insight into the metabolic preference of
L. acidophilus
for α-glucans with short α-1,6-branches. The unprecedented affinity of the debranching enzyme that confers growth on these substrates reflects its adaptation to the nutrient-competitive gut ecological niche and constitutes a potential advantage in cross-feeding from human and bacterial dietary starch metabolism.
The Current State of Macrolide Resistance in Campylobacter spp.: Trends and Impacts of Resistance Mechanisms
Authors: Bolinger Hannah , Kathariou Sophia
Published: April 2017

Campylobacter
spp., especially
Campylobacter jejuni
and
C. coli
, are leading bacterial foodborne pathogens worldwide. In the United States, an estimated 0.8 million cases of campylobacteriosis occur annually, mostly involving
C. jejuni
. Campylobacteriosis is generally self-limiting, but in severe cases, treatment with antibiotics may be mandated. The increasing incidence of fluoroquinolone resistance in
Campylobacter
has rendered macrolides such as erythromycin and azithromycin the drugs of choice for human campylobacteriosis. The prevalence of macrolide resistance in
C. jejuni
remains low, but macrolide resistance can be common in
C. coli
. Substitutions in the 23S rRNA gene, specifically A2075G, and less frequently A2074C/G, remain the most common mechanism for high-level resistance to macrolides. In
C. jejuni
, resistance mediated by such substitutions is accompanied by a reduced ability to colonize chickens and other fitness costs, potentially contributing to the low incidence of macrolide resistance. Interestingly, similar fitness impacts have not been noted in
C. coli
. Also noteworthy is a novel mechanism first reported in 2014 for a
C. coli
isolate from China and mediated by
erm
(B) harbored on multidrug resistance genomic islands. The incidence of
erm
(B) appears to reflect clonal expansion of certain strains, and whole-genome sequencing has been critical to the elucidation of
erm
(B)-associated macrolide resistance in
Campylobacter
spp. With the exception of one report from Spain,
erm
(B)-mediated macrolide resistance has been restricted to
Campylobacter
spp., mostly
C. coli
, of animal and human origin from China. If
erm
(B)-mediated macrolide resistance does not confer fitness costs in
C. jejuni
, the range of this gene may expand in
C. jejuni
, threatening to compromise treatment effectiveness for severe campylobacteriosis cases.
Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms
Authors: Mantilla-Calderon David , Hong Pei-Ying
Published: April 2017

The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positiveEscherichia colistrain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed thatE. coliPI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation,E. coliPI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000E. colicells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with theE. coliPI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination ofE. coliin the environment during reuse events of treated wastewater.

IMPORTANCEThis study examines the decay kinetics of a pathogenic and antibiotic resistant strain ofEscherichia coliin microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of theE. coliand the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene was detected in the aerobic sludge by a cultivation method. A subpopulation of persisterE. colicells was also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistantE. coliduring both anaerobic and aerobic sludge treatment processes.