bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the efficacy of 308‐nm excimer lamp monotherapy with topical tacrolimus or clobetasol 17‐propionate combination therapies in localized vitiligo
Authors: Bapur Erduran Funda , Adışen Esra
Published: August 2016

Background

In recent years, excimer light treatments have come to the fore in localized vitiligo because of their high efficacy and safety.

Objective

We aimed to evaluate the efficacy of 308‐nm excimer lamp as a monotherapy and its combination with tacrolimus 0.1% or clobetasol 17‐propionate 0.05% ointment in localized vitiligo.

Methods

We performed a retrospective study including a total of 82 patients who were treated with excimer lamp monotherapy (EL group) (n = 30), excimer lamp + topical tacrolimus (EL + T group) (n = 29), or excimer lamp + topical clobetasol 17‐propionate (EL + CS group) (n = 23). We used digital morphometric analysis for the evaluation of repigmentation.

Results

Median healing rate after 24 sessions was significantly higher in EL + T group (69%) than EL (42.5%) and EL + CS (44%) groups (P = 0.008 and P = 0.032). There were not any patients with face lesions in EL + CS group, so when these patients were excluded, EL + T and EL + CS groups had higher healing rates than EL group (P = 0.037 and P = 0.043). It was confirmed that combination with tacrolimus was superior to clobetasol‐17 propionate (P = 0.048) with multivariate regression analysis.

Conclusion

We noted that 308‐nm excimer lamp therapy was efficacious; adding topical tacrolimus or topical clobetasol‐17 propionate could increase response to treatment.
Expression of RANKL by peripheral neutrophils and its association with bone mineral density in COPD
Authors: Hu XiaoLing , Sun Yongchang , Xu Weihan , Lin Tao , Zeng Hui
Published: August 2016

ABSTRACT

Background and objective

Osteoporosis is a major co‐morbidity of COPD, but the mechanistic links between diseases of the lung and the bone remain elusive. Human neutrophils express the osteoclast activation factor RANKL (receptor activator of NF‐kB ligand) and act directly on osteoclasts to promote bone loss. Given that neutrophils are key effector cells in the pathogenesis of COPD, these same cells, by expressing RANKL, may be involved in osteoporosis of COPD.

Methods

We enrolled 59 male patients with COPD, 32 smokers with normal lung function and 25 healthy non‐smokers of the same gender as controls. The expression of RANKL on peripheral neutrophils was detected by flow cytometry. The plasma concentrations of pro‐inflammatory cytokines were measured by ELISA. We analysed the association of RANKL
+ neutrophils with bone mineral density (BMD), lung function and the levels of cytokines.

Results

RANKL
+ neutrophils in the blood of COPD patients were increased as compared to smokers and healthy controls, and the percentage of RANKL
+ neutrophils was higher in patients with low BMD as compared to those with normal BMD. The percentage of RANKL
+ neutrophils showed negative correlations with BMD and forced expiratory volume in 1 s (FEV1) % predicted. Further analysis showed that activated neutrophils were increased and expressed a higher level of RANKL in COPD patients. Plasma levels of IL‐1β, IL‐6 and IL‐8 were increased in COPD patients and correlated with RANKL expression by neutrophils.

Conclusion

Our results show that RANKL‐expressing neutrophils are increased in male patients with COPD and associated with BMD and lung function, suggesting that these cells may play a role in osteoclastogenesis in COPD.
Role of anxiety and brooding in specificity of autobiographical recall
Authors: Ricarte Jorge Javier , Ros Laura , Latorre Jose Miguel , Muñoz Maria Dolores , Aguilar Maria Jose , Hernandez Jose Vicente
Published: August 2016

Overgeneral schemas and lack of autobiographical memory (AM) specificity about our past experiences can predict mood disturbance. Rumination, functional avoidance and executive processes are the main explanatory variables of such overgenerality. However, in non‐clinical samples, rumination predicts overgenerality most consistently after the induction of dysphoric mood. Anxiety also activates rumination. Furthermore, anxiety predicts memory performance and has effects on mood which are independent of the effects of rumination. So, what might be the role of anxiety in autobiographical memory performance? A sample of 210 voluntary participants reported measures of autobiographical memory, anxiety, rumination (brooding and reflection), functional avoidance and executive functions (semantic and phonetic verbal fluency task). Autobiographical performance (specificity) was negatively associated with brooding and age and positively with phonetic verbal fluency but not with functional avoidance and anxiety. However, anxiety and brooding were positively correlated even after controlling for depression scores. Moreover, using structural equation modeling, anxiety showed a significant indirect effect on autobiographical specificity through brooding rumination. These results suggest a possible association of anxiety with autobiographical recall through brooding rumination.
Rab24 interacts with the Rab7/Rab interacting lysosomal protein complex to regulate endosomal degradation
Authors: Amaya Celina , Militello Rodrigo D. , Calligaris Sebastián D. , Colombo María I.
Published: August 2016

Endocytosis is a multistep process engaged in extracellular molecules internalization. Several proteins including the Rab GTPases family coordinate the endocytic pathway. The small GTPase Rab7 is present in late endosome (LE) compartments being a marker of endosome maturation. The Rab interacting lysosomal protein (RILP) is a downstream effector of Rab7 that recruits the functional dynein/dynactin motor complex to late compartments. In the present study, we have found Rab24 as a component of the endosome‐lysosome degradative pathway. Rab24 is an atypical protein of the Rab GTPase family, which has been attributed a function in vesicle trafficking and autophagosome maturation. Using a model of transiently expressed proteins in K562 cells, we found that Rab24 co‐localizes in vesicular structures labeled with Rab7 and LAMP1. Moreover, using a dominant negative mutant of Rab24 or a siRNA‐Rab24 we showed that the distribution of Rab7 in vesicles depends on a functional Rab24 to allow DQ‐BSA protein degradation. Additionally, by immunoprecipitation and pull down assays, we have demonstrated that Rab24 interacts with Rab7 and RILP. Interestingly, overexpression of the Vps41 subunit from the homotypic fusion and protein‐sorting (HOPS) complex hampered the co‐localization of Rab24 with RILP or with the lysosomal GTPase Arl8b, suggesting that Vps41 would affect the Rab24/RILP association. In summary, our data strongly support the hypothesis that Rab24 forms a complex with Rab7 and RILP on the membranes of late compartments. Our work provides new insights into the molecular function of Rab24 in the last steps of the endosomal degradative pathway.
Orf virus interleukin‐10 and vascular endothelial growth factor‐E modulate gene expression in cultured equine dermal fibroblasts
Authors: Wise Lyn M. , Bodaan Christa J. , Mercer Andrew A. , Riley Christopher B. , Theoret Christine L.
Published: August 2016

Background

Wounds in horses often exhibit sustained inflammation and inefficient vascularization, leading to excessive fibrosis and clinical complications such as “proud flesh”. Orf virus‐derived proteins, vascular endothelial growth factor (VEGF)‐E and interleukin (ovIL)‐10, enhance angiogenesis and control inflammation and fibrosis in skin wounds of laboratory animals.

Hypothesis/Objectives

The study aimed to determine if equine dermal cells respond to VEGF‐E and ovIL‐10. Equine dermal cells are expected to express VEGF and IL‐10 receptors, so viral protein treatment is likely to alter cellular gene expression and behaviour in a manner conducive to healing.

Animals

Skin samples were harvested from the lateral thoracic wall of two healthy thoroughbred horses.

Methods

Equine dermal cells were isolated using a skin explant method and their phenotype assessed by immunofluorescence. Cells were treated with recombinant proteins, with or without inflammatory stimuli. Gene expression was examined using standard and quantitative reverse transcriptase PCR. Cell behaviour was evaluated in a scratch assay.

Results

Cultured cells were half vimentin+ve fibroblasts and half alpha smooth muscle actin+ve and vimentin+ve myofibroblasts. VEGF‐E increased basal expression of IL‐10 mRNA, whereas VEGF‐A and collagenase‐1 mRNA expression was increased by ovIL‐10. In cells exposed to inflammatory stimulus, both treatments dampened tumour necrosis factor mRNA expression, and ovIL‐10 exacerbated expression of monocyte chemoattractant protein. Neither viral protein influenced cell migration greatly.

Conclusions and clinical importance

This study shows that VEGF‐E and ovIL‐10 are active on equine dermal cells and exert anti‐inflammatory and anti‐fibrotic effects that may enhance skin wound healing in horses.
Histopathological and biochemical effects of cyanobacterial cells containing microcystin‐LR on Tilapia fish
Authors: Preeti T. , Hariharan G. , Rajarajeswari G.R.
Published: August 2016

Blooms of Microcystis aeruginosa, commonly observed in many lakes of Tamil Nadu, produce the cyanobacterial toxin Microcystin, which has tumor promoting property in fish. Strains of Microcystis aeruginosa species have the same morphology but may vary in their toxicity. In the present study, Microcystin produced by Microcystis aeruginosa from Thenneri lake in Kancheepuram district of Tamil Nadu, was isolated and characterized by high‐performance liquid chromatography and electron spray ionization mass spectroscopy. Based on spectroscopic results the toxin was identified as Microcystin‐LR. Toxicogenicity was evident from the alteration in the activity of antioxidant enzymes [Glutathione S‐transferase and Catalase] and increase of protein and lipid peroxidation contents in Oreochromis niloticus, a fresh water fish species, after controlled exposure to Microcystis aeruginosa cells. Toxicity was further confirmed by histopathological changes in gill, liver and intestine of exposed fish.
Effect of Temperature Difference on In-Tube Condensation Heat Transfer Coefficients
Authors: Macdonald Malcolm , Garimella Srinivas
Published: August 2016

The effect of temperature difference (Tsat − Tcoolant) on condensation heat transfer coefficients inside horizontal tubes is investigated in detail. Condensation experiments are conducted on propane inside a 7.75 mm horizontal tube at four temperature differences between the test fluid and coolant at three mass fluxes and four saturation temperatures. The heat transfer coefficient is shown to increase with temperature difference, with this effect diminishing with larger temperature differences, and being most significant at higher saturation temperatures. Heat transfer coefficients at the low-reduced pressures (Pr = 0.25) corresponding to lower saturation temperatures (30 °C) are mostly unaffected by the temperature difference. Subcooling of the condensate is expected to increase heat transfer coefficients at the larger temperature differences. Flow visualization studies are used to explain the inadequacy of the Nusselt film theory for the conditions investigated. The underlying mechanisms are also used to explain why the correlations from the literature do not predict the observed trend, and a new correlation to account for the effect of temperature difference is developed.
Parallelized, Automated, and Predictive Imprint Cooling Model for Combustion Systems
Authors: Briones Alejandro M. , Rankin Brent A. , Stouffer Scott D. , Erdmann Timothy J. , Burrus David L.
Published: August 2016

A novel parallelized, automated, and predictive imprint cooling model (PAPRICO) was developed for modeling of combustor liners using Reynolds-averaged Navier–Stokes (RANS). The methodology involves removing the film and effusion cooling jet geometry from the liner while retaining the cooling hole imprints on the liner. The PAPRICO can operate under two modalities, viz., two-sided and one-sided. For the two-sided PAPRICO model, the imprints are kept on the plenum and combustor sides of the liner. For the one-sided PAPRICO model, the imprints are retained only on the combustor side of the liner and there is no need for a plenum. The PAPRICO model neither needs a priori knowledge of the cooling flow rates through various combustor liner regions nor specific mesh partitioning. The imprint mass flow rate, momentum, enthalpy, turbulent kinetic energy, and eddy dissipation rate are included in the governing equations as volumetric source terms in cells adjacent to the liner on the combustor side. Additionally, the two-sided PAPRICO model includes corresponding volumetric sinks in cells adjacent to the liner on the plenum side. A referee combustor liner was simulated using PAPRICO under nonreacting flow conditions. The PAPRICO results were compared against predictions of nonreacting flow results of a resolved liner geometry, against a combustor liner with prescribed mass and enthalpy source terms (simplified liner) and against measurements. The results clearly conclude that PAPRICO can qualitatively and quantitatively emulate the local turbulent flow field with a reduced mesh size. The simplified liner fails to emulate the local turbulent flow field.
Experimental Evaluation of Compressor Blade Fouling
Authors: Kurz Rainer , Musgrove Grant , Brun Klaus
Published: August 2016

Fouling of compressor blades is an important mechanism leading to performance deterioration in gas turbines over time. Experimental and simulation data are available for the impact of specified amounts of fouling on the performance as well as the amount of foulants entering the engine for defined air filtration systems and ambient conditions. This study provides experimental data on the amount of foulants in the air that actually stick to a blade surface for different conditions. Quantitative results both indicate the amount of dust as well as the distribution of dust on the airfoil, for a dry airfoil, and also the airfoils that were wet from ingested water, in addition to, different types of oil. The retention patterns are correlated with the boundary layer shear stress. The tests show the higher dust retention from wet surfaces compared to dry surfaces. They also provide information about the behavior of the particles after they impact on the blade surface, showing for a certain amount of wet film thickness, the shear forces actually wash the dust downstream and off the airfoil. Further, the effect of particle agglomeration of particles to form larger clusters was observed, which would explain the disproportional impact of very small particles on boundary layer losses.
Liquid Fuel Composition Effects on Forced, Nonpremixed Ignition
Authors: Sforzo Brandon , Dao Hoang , Wei Sheng , Seitzman Jerry
Published: August 2016

The effects of jet fuel composition on ignition probability have been studied in a flowfield that is relevant to turbine engine combustors, but also fundamental and conducive to modeling. In the experiments, a spark kernel is ejected from a wall and propagates transversely into a crossflow. The kernel first encounters an air-only stream before transiting into a second, flammable (premixed) stream. The two streams have matched velocities, as verified by hot-wire measurements. The liquid fuels span a range of physical and chemical kinetic properties. To focus on their chemical differences, the fuels are prevaporized in a carrier air flow before being injected into the experimental facility. Ignition probabilities at atmospheric pressure and elevated crossflow temperature were determined from optical measurements of a large number of spark events, and high-speed imaging was used to characterize the kernel evolution. Eight fuel blends were tested experimentally; all exhibited increasing ignition probability as equivalence ratio increased, at least up to the maximum value studied (∼0.8). Statistically significant differences between fuels were measured that have some correlation with fuel properties. To elucidate these trends, the forced ignition process was also studied with a reduced-order numerical model of an entraining kernel. The simulations suggest ignition is successful if sufficient heat release occurs before entrainment of colder crossflow fluid quenches the exothermic oxidation reactions. As the kernel is initialized in air, it remains extremely lean during the initial entrainment of the fuel–air mixture; thus, richer crossflows lead to quicker and higher exothermicity.
Full Three-Dimensional Rotor/Stator Interaction Simulations in Aircraft Engines With Time-Dependent Angular Speed
Authors: Batailly Alain , Legrand Mathias , Pierre Christophe
Published: August 2016

Modern aircraft engine designs feature reduced clearances that may initiate structural contacts between rotating and static components. A numerical strategy dedicated to the simulation of such interactions is here enriched in order to account for time-dependent angular speeds. This contribution first details the evolution of the numerical strategy before validating the developments by comparing numerical results with experimental observations made on an industrial test bench. Further, numerical investigations allow to assess the sensitivity of the numerical results to acceleration and deceleration rates. The results, obtained with and without abradable coating, underline the fundamental nonlinear nature of the analyzed system. It is found that the lower acceleration rates favor the arisal of interaction phenomena, and that the amplitudes of vibration at a given angular speed are generally lower when the blade decelerates.
Performance of Proportional Flow Valve With Pilot Pressure Drop—Spool Opening Compensation
Authors: Huang Jiahai , Dai Jiangjiao , Quan Long , Lan Yuan
Published: August 2016

Flow control valves are extensively used to control the motion of hydraulic actuators in industry. In this paper, a two-stage proportional flow control valve with pilot digital pressure compensator is presented. The proposed valve is composed of two pressure sensors, a proportional pilot valve, a Valvistor poppet valve (main stage), and an electronic controller. The pressure drop across the pilot valve metering orifice is detected by two pressure sensors and fed into the controller which changes the pilot valve input voltage to compensate pressure influence on the outlet flow. The presented valve is investigated theoretically by simplified analytical models as well as numerical methods and also evaluated experimentally. The results show that the proposed scheme is feasible. It has a reasonable static performance and an acceptable dynamic characteristic for low bandwidth disturbances. The flow force on the Valvistor poppet should be estimated and considered in the controller design.
A Comparative Study of the Energy-Saving Controllers for Automotive Air-Conditioning/Refrigeration Systems
Authors: Huang Yanjun , Khajepour Amir , Khazraee Milad , Bahrami Majid
Published: August 2016

With the extensive application of air-conditioning/refrigeration (A/C-R) systems in homes, industry, and vehicles, many efforts have been put toward the controller development for A/C-R systems. Therefore, this paper proposes an energy-saving model predictive controller (MPC) via a comparative study of several control approaches that could be applied in automotive A/C-R systems. The on/off controller is first presented and used as a basis to compare with others. The conventional proportional-integral (PI) as well as a set-point controller follows. In the set-point controller, the sliding mode control (SMC) strategies are also employed. Then, the MPC is elaborated upon. Finally, the simulation and experimental results under the same scenario are compared to demonstrate how the advanced MPC can bring more benefits in terms of performance and energy saving (10%) over the conventional controllers.
Dynamic Balanced Reach: A Temporal and Spectral Analysis Across Increasing Performance Demands
Authors: Barton Joseph E. , Graci Valentina , Hafer-Macko Charlene , Sorkin John D. , F. Macko Richard
Published: August 2016

Standing balanced reach is a fundamental task involved in many activities of daily living that has not been well analyzed quantitatively to assess and characterize the multisegmental nature of the body's movements. We developed a dynamic balanced reach test (BRT) to analyze performance in this activity; in which a standing subject is required to maintain balance while reaching and pointing to a target disk moving across a large projection screen according to a sum-of-sines function. This tracking and balance task is made progressively more difficult by increasing the disk's overall excursion amplitude. Using kinematic and ground reaction force data from 32 young healthy subjects, we investigated how the motions of the tracking finger and whole-body center of mass (CoM) varied in response to the motion of the disk across five overall disk excursion amplitudes. Group representative performance statistics for the cohort revealed a monotonically increasing root mean squared (RMS) tracking error (RMSE) and RMS deviation (RMSD) between whole-body CoM (projected onto the ground plane) and the center of the base of support (BoS) with increasing amplitude (p < 0.03). Tracking and CoM response delays remained constant, however, at 0.5 s and 1.0 s, respectively. We also performed detailed spectral analyses of group-representative response data for each of the five overall excursion amplitudes. We derived empirical and analytical transfer functions between the motion of the disk and that of the tracking finger and CoM, computed tracking and CoM responses to a step input, and RMSE and RMSD as functions of disk frequency. We found that for frequencies less than 1.0 Hz, RMSE generally decreased, while RMSE normalized to disk motion amplitude generally increased. RMSD, on the other hand, decreased monotonically. These findings quantitatively characterize the amplitude- and frequency-dependent nature of young healthy tracking and balance in this task. The BRT is not subject to floor or ceiling effects, overcoming an important deficiency associated with most research and clinical instruments used to assess balance. This makes a comprehensive quantification of young healthy balance performance possible. The results of such analyses could be used in work space design and in fall-prevention instructional materials, for both the home and work place. Young healthy performance represents “exemplar” performance and can also be used as a reference against which to compare the performance of aging and other clinical populations at risk for falling.
Observer-Based Estimation of Aging Condition for Selective Catalytic Reduction Systems in Vehicle Applications
Authors: Ma Yao , Wang Junmin
Published: August 2016

This paper presents two observers for estimating the aging condition of selective catalytic reduction (SCR) systems in vehicle applications. SCR systems have been widely recognized as one of the leading engine exhaust gas aftertreatment systems for reducing diesel powertrain tailpipe NOx emissions in ground vehicle applications. While fresh SCRs are quite effective in reducing tailpipe NOx emissions, their NOx reduction capabilities and performances may substantially degrade with in-service aging. To maintain the emission control performance of a SCR system for a diesel engine during the entire vehicle service life, it is thus critical to have an accurate estimation of the SCR system aging condition. In this paper, two Lyapunov-based observers utilizing the measurements of NOx and ammonia concentrations are analytically developed and verified in simulations for estimating the SCR aging condition. The measurement uncertainty is explicitly considered in the observer design process. A sufficient condition for the boundedness of the estimation error is derived. Simulation results under the US06 test cycle demonstrate the effectiveness of the proposed observers.
Technical Note: plastimatch mabs, an open source tool for automatic image segmentation
Authors: Zaffino Paolo , Raudaschl Patrik , Fritscher Karl , Sharp Gregory C. , Spadea Maria Francesca
Published: August 2016

Purpose:

Multiatlas based segmentation is largely used in many clinical and research applications. Due to its good performances, it has recently been included in some commercial platforms for radiotherapy planning and surgery guidance. Anyway, to date, a software with no restrictions about the anatomical district and image modality is still missing. In this paper we introduce plastimatch mabs, an open source software that can be used with any image modality for automatic segmentation.

Methods:

plastimatch mabs workflow consists of two main parts: (1) an offline phase, where optimal registration and voting parameters are tuned and (2) an online phase, where a new patient is labeled from scratch by using the same parameters as identified in the former phase. Several registration strategies, as well as different voting criteria can be selected. A flexible atlas selection scheme is also available. To prove the effectiveness of the proposed software across anatomical districts and image modalities, it was tested on two very different scenarios: head and neck (H&N) CT segmentation for radiotherapy application, and magnetic resonance image brain labeling for neuroscience investigation.

Results:

For the neurological study, minimum dice was equal to 0.76 (investigated structures: left and right caudate, putamen, thalamus, and hippocampus). For head and neck case, minimum dice was 0.42 for the most challenging structures (optic nerves and submandibular glands) and 0.62 for the other ones (mandible, brainstem, and parotid glands). Time required to obtain the labels was compatible with a real clinical workflow (35 and 120 min).

Conclusions:

The proposed software fills a gap in the multiatlas based segmentation field, since all currently available tools (both for commercial and for research purposes) are restricted to a well specified application. Furthermore, it can be adopted as a platform for exploring MABS parameters and as a reference implementation for comparing against other segmentation algorithms.
A particle filter based autocontouring algorithm for lung tumor tracking using dynamic magnetic resonance imaging
Authors: Bourque Alexandra E. , Bedwani Stéphane , Filion Édith , Carrier Jean‐François
Published: August 2016

Purpose:

This study introduces a novel autocontouring algorithm based on particle filter for lung tumors. It is validated on dynamic magnetic resonance (MR) images and is developed in the context of MR‐linac treatments.

Methods:

A sequential Monte Carlo method called particle filter is used as the main structure of the algorithm and is combined with Otsu's thresholding technique to contour lung tumors on dynamic MR images. Four non‐small cell lung cancer (NSCLC) patients were imaged with a 1.5 T MR for 60 s at a rate of 4 images/s and were asked to breathe normally. Prior to treatment, some image processing is required by the proposed algorithm, which includes a manual contour of the tumor, the tumor's displacement, and its descriptive statistics. During treatment, the contours are automatically generated by thresholding around the center of mass of the particles. A comparison with the expert's contours is obtained by calculating the Dice similarity coefficient (DSC), the precision, the recall, the Hausdorff distance, and the difference in centroid positions (Δd).

Results:

This autocontouring algorithm is independent of pretreatment training and presents continuous adaptability as provided by the nature of particle filters. The number of particles is proportional to the area of the tumor and increases the computational time at a rate of 2 ms for every 500 particles, whereas the contouring step adds a constant 14 ms. The contours’ comparison is obtained with a mean DSC of 0.89–0.91, mean precision of 0.88–0.91, mean recall of 0.89–0.95, and mean Δd of 0.6–2.0 mm.

Conclusions:

This work presents a proof of concept of a new autocontouring algorithm for NSCLC patients on dynamic MR images. The contours were generated in good agreement with the expert's contours.
Dynamic DNA methylation regulates neuronal intrinsic membrane excitability
Authors: Meadows Jarrod P. , Guzman-Karlsson Mikael C. , Phillips Scott , Brown Jordan A. , Strange Sarah K. , Sweatt J. David , Hablitz John J.
Published: August 2016

The intrinsic excitability of cortical pyramidal neurons is set by dynamic DNA cytosine methylation.
Ras and TGF-β signaling enhance cancer progression by promoting the ΔNp63 transcriptional program
Authors: Vasilaki Eleftheria , Morikawa Masato , Koinuma Daizo , Mizutani Anna , Hirano Yudai , Ehata Shogo , Sundqvist Anders , Kawasaki Natsumi , Cedervall Jessica , Olsson Anna-Karin , Aburatani Hiroyuki , Moustakas Aristidis , Miyazono Kohei , Heldin Carl-Henrik
Published: August 2016

In tumors with mutant p53, both Ras and TGF-β promote metastatic disease by stimulating ΔNp63 activity.
Dual Targeting of Cell Wall Precursors by Teixobactin Leads to Cell Lysis
Authors: Homma Tomoyuki , Nuxoll Austin , Gandt Autumn Brown , Ebner Patrick , Engels Ina , Schneider Tanja , Götz Friedrich , Lewis Kim , Conlon Brian P.
Published: August 2016

Teixobactin represents the first member of a newly discovered class of antibiotics that act through inhibition of cell wall synthesis. Teixobactin binds multiple bactoprenol-coupled cell wall precursors, inhibiting both peptidoglycan and teichoic acid synthesis. Here, we show that the impressive bactericidal activity of teixobactin is due to the synergistic inhibition of both targets, resulting in cell wall damage, delocalization of autolysins, and subsequent cell lysis. We also find that teixobactin does not bind mature peptidoglycan, further increasing its activity at high cell densities and against vancomycin-intermediate
Staphylococcus aureus
(VISA) isolates with thickened peptidoglycan layers. These findings add to the attractiveness of teixobactin as a potential therapeutic agent for the treatment of infection caused by antibiotic-resistant Gram-positive pathogens.
Population Pharmacokinetics and Safety of Ceftolozane-Tazobactam in Adult Cystic Fibrosis Patients Admitted with Acute Pulmonary Exacerbation
Authors: Monogue Marguerite L. , Pettit Rebecca S. , Muhlebach Marianne , Cies Jeffrey J. , Nicolau David P. , Kuti Joseph L.
Published: August 2016

Ceftolozane-tazobactam has potent activity against
Pseudomonas aeruginosa
, a pathogen associated with cystic fibrosis (CF) acute pulmonary exacerbations (APE). Due to the rapid elimination of many antibiotics, CF patients frequently have altered pharmacokinetics. In this multicenter, open-label study, we described the population pharmacokinetics and safety of ceftolozane-tazobactam at 3 g every 8 h (q8h) in 20 adult CF patients admitted with APE. Population pharmacokinetics were determined using the nonparametric adaptive grid program in Pmetrics for R. A 5,000-patient Monte Carlo simulation was performed to determine the probability of target attainment (PTA) for the ceftolozane component at 1.5 g and 3 g of ceftolozane-tazobactam q8h across a range of MICs using a primary threshold exposure of 60% free time above the MIC (
fT
>MIC). In these 20 adult CF patients, ceftolozane and tazobactam concentration data were best described by 2-compartment models, and ceftolozane clearance (CL) was significantly correlated with creatinine clearance (
r
= 0.71,
P
< 0.001). These data suggest that ceftolozane and tazobactam clearance estimates in CF patients are similar to those in adults without CF (ceftolozane CF CL, 4.76 ± 1.13 liter/h; tazobactam CF CL, 20.51 ± 4.41 liter/h). However, estimates of the volume of the central compartment (

V
c

) were lower than those for adults without CF (ceftolozane CF

V
c

, 7.51 ± 2.05 liters; tazobactam CF

V
c

, 7.85 ± 2.66 liters). Using a threshold of 60%
fT
>MIC, ceftolozane-tazobactam regimens of 1.5 g and 3 g q8h should achieve PTAs of ≥90% at MICs up to 4 and 8 μg/ml, respectively. Ceftolozane-tazobactam at 3 g q8h was well tolerated. These observations support additional studies of ceftolozane-tazobactam for
Pseudomonas aeruginosa
APE in CF patients. (This study has been registered at ClinicalTrials.gov under identifier NCT02421120.)
Transposon-Sequencing Analysis Unveils Novel Genes Involved in the Generation of Persister Cells in Uropathogenic Escherichia coli
Authors: Molina-Quiroz Roberto C. , Lazinski David W. , Camilli Andrew , Levy Stuart B.
Published: August 2016

Persister cells are highly tolerant to different antibiotics and are associated with relapsing infections. In order to understand this phenomenon further, we exposed a transposon library to a lethal concentration of ampicillin, and mutants that survived were identified by transposon sequencing (Tn-Seq). We determined that mutations related to carbon metabolism, cell envelope (cell wall generation and membrane proteins), and stress response have a role in persister cell generation.
Polysaccharide Capsule Composition of Pneumococcal Serotype 19A Subtypes Is Unaltered among Subtypes and Independent of the Nutritional Environment
Authors: Brugger Silvio D. , Troxler Lukas J. , Rüfenacht Susanne , Frey Pascal M. , Morand Brigitte , Geyer Rudolf , Mühlemann Kathrin , Höck Stefan , Thormann Wolfgang , Furrer Julien , Christen Stephan , Hilty Markus
Published: August 2016

Serotype 19A strains have emerged as a cause of invasive pneumococcal disease after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7), and serotype 19A has now been included in the recent 13-valent vaccine (PCV13). Genetic analysis has revealed at least three different capsular serotype 19A subtypes, and nutritional environment-dependent variation of the 19A capsule structure has been reported. Pneumococcal vaccine effectiveness and serotyping accuracy might be impaired by structural differences in serotype 19A capsules. We therefore analyzed the distribution of 19A subtypes collected within a Swiss national surveillance program and determined capsule composition under different nutritional conditions with high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. After the introduction of PCV7, a significant relative increase of subtype 19A-II and decrease of 19A-I occurred. Chemical analyses showed no difference in the composition as well as the linkage of 19A subtype capsular saccharides grown in defined and undefined growth media, which is consistent with a trisaccharide repeat unit composed of rhamnose,
N
-acetyl-mannosamine, and glucose. In summary, our study suggests that no structural variance dependent of the nutritional environment or the subtype exists. The serotype 19A subtype shift observed after the introduction of the PCV7 can therefore not be explained by selection of a capsule structure variant. However, capsule composition analysis of emerging 19A clones is recommended in cases where there is no other explanation for a selective advantage, such as antibiotic resistance or loss or acquisition of other virulence factors.
Yersinia enterocolitica YopH-Deficient Strain Activates Neutrophil Recruitment to Peyer's Patches and Promotes Clearance of the Virulent Strain
Authors: Dave Mabel N. , Silva Juan E. , Eliçabe Ricardo J. , Jeréz María B. , Filippa Verónica P. , Gorlino Carolina V. , Autenrieth Stella , Autenrieth Ingo B. , Di Genaro María S.
Published: August 2016

Yersinia enterocolitica
evades the immune response by injecting
Yersinia
outer proteins (Yops) into the cytosol of host cells. YopH is a tyrosine phosphatase critical for
Yersinia
virulence. However, the mucosal immune mechanisms subverted by YopH during
in vivo
orogastric infection with
Y. enterocolitica
remain elusive. The results of this study revealed neutrophil recruitment to Peyer's patches (PP) after infection with a YopH-deficient mutant strain (
Y. enterocolitica
Δ
yopH
). While the
Y. enterocolitica
wild-type (WT) strain in PP induced the major neutrophil chemoattractant CXCL1 mRNA and protein levels, infection with the
Y. enterocolitica
Δ
yopH
mutant strain exhibited a higher expression of the CXCL1 receptor, CXCR2, in blood neutrophils, leading to efficient neutrophil recruitment to the PP. In contrast, migration of neutrophils into PP was impaired upon infection with
Y. enterocolitica
WT strain.
In vitro
infection of blood neutrophils revealed the involvement of YopH in CXCR2 expression. Depletion of neutrophils during
Y. enterocolitica
Δ
yopH
infection raised the bacterial load in PP. Moreover, the clearance of WT
Y. enterocolitica
was improved when an equal mixture of
Y. enterocolitica
WT and
Y. enterocolitica
Δ
yopH
strains was used in infecting the mice. This study indicates that
Y. enterocolitica
prevents early neutrophil recruitment in the intestine and that the effector protein YopH plays an important role in the immune evasion mechanism. The findings highlight the potential use of the
Y. enterocolitica
YopH-deficient strain as an oral vaccine carrier.
Vitamin D and Lung Infection
Authors: Cantorna Margherita T.
Published: August 2016

Available data suggest that vitamin D plays a role in controlling inflammation in the lungs. However, to date vitamin D-induced production of cathelicidin has not been shown to have an effect on the burden of either viruses or bacteria. Future work should continue to determine the effects of vitamin D-regulated mechanisms in the lung and the possible role of cathelicidin against different pulmonary pathogens
in vivo
.
ZpdN, a Plasmid-Encoded Sigma Factor Homolog, Induces pBS32-Dependent Cell Death in Bacillus subtilis
Authors: Myagmarjav B.-E. , Konkol M. A. , Ramsey J. , Mukhopadhyay S. , Kearns D. B.
Published: August 2016

The ancestral
Bacillus subtilis
strain 3610 contains an 84-kb plasmid called pBS32 that was lost during domestication of commonly used laboratory derivatives. Here we demonstrate that pBS32, normally present at 1 or 2 copies per cell, increases in copy number nearly 100-fold when cells are treated with the DNA-damaging agent mitomycin C. Mitomycin C treatment also caused cell lysis dependent on pBS32-borne prophage genes. ZpdN, a sigma factor homolog encoded by pBS32, was required for the plasmid response to DNA damage, and artificial expression of ZpdN was sufficient to induce pBS32 hyperreplication and cell death. Plasmid DNA released by cell death was protected by the capsid protein ZpbH, suggesting that the plasmid was packaged into a phagelike particle. The putative particles were further indicated by CsCl sedimentation but were not observed by electron microscopy and were incapable of killing
B. subtilis
cells extracellularly. We hypothesize that pBS32-mediated cell death releases a phagelike particle that is defective and unstable.

IMPORTANCE
Prophages are phage genomes stably integrated into the host bacterium's chromosome and less frequently are maintained as extrachromosomal plasmids. Here we report that the extrachromosomal plasmid pBS32 of
Bacillus subtilis
encodes a prophage that, when activated, kills the host. pBS32 also encodes both the sigma factor homolog ZpdN that is necessary and sufficient for prophage induction and the protein ComI, which is a potent inhibitor of DNA uptake by natural transformation. We provide evidence that the entire pBS32 sequence may be part of the prophage and thus that competence inhibition may be linked to lysogeny.
Neisseria gonorrhoeae Crippled Its Peptidoglycan Fragment Permease To Facilitate Toxic Peptidoglycan Monomer Release
Authors: Chan Jia Mun , Dillard Joseph P.
Published: August 2016

Neisseria gonorrhoeae
(gonococci) and
Neisseria meningitidis
(meningococci) are human pathogens that cause gonorrhea and meningococcal meningitis, respectively. Both
N. gonorrhoeae
and
N. meningitidis
release a number of small peptidoglycan (PG) fragments, including proinflammatory PG monomers, although
N. meningitidis
releases fewer PG monomers. The PG fragments released by
N. gonorrhoeae
and
N. meningitidis
are generated in the periplasm during cell wall remodeling, and a majority of these fragments are transported into the cytoplasm by an inner membrane permease, AmpG; however, a portion of the PG fragments are released into the extracellular environment through unknown mechanisms. We previously reported that the expression of meningococcal
ampG
in
N. gonorrhoeae
reduced PG monomer release by gonococci. This finding suggested that the efficiency of AmpG-mediated PG fragment recycling regulates the amount of PG fragments released into the extracellular milieu. We determined that three AmpG residues near the C-terminal end of the protein modulate AmpG's efficiency. We also investigated the association between PG fragment recycling and release in two species of human-associated nonpathogenic
Neisseria
:
N. sicca
and
N. mucosa
. Both
N. sicca
and
N. mucosa
release lower levels of PG fragments and are more efficient at recycling PG fragments than
N. gonorrhoeae
. Our results suggest that
N. gonorrhoeae
has evolved to increase the amounts of toxic PG fragments released by reducing its PG recycling efficiency.

IMPORTANCE
Neisseria gonorrhoeae
and
Neisseria meningitidis
are human pathogens that cause highly inflammatory diseases, although
N. meningitidis
is also frequently found as a normal member of the nasopharyngeal microbiota. Nonpathogenic
Neisseria
, such as
N. sicca
and
N. mucosa
, also colonize the nasopharynx without causing disease. Although all four species release peptidoglycan fragments,
N. gonorrhoeae
is the least efficient at recycling and releases the largest amount of proinflammatory peptidoglycan monomers, partly due to differences in the recycling permease AmpG. Studying the interplay between bacterial physiology (peptidoglycan metabolism) and pathogenesis (release of toxic monomers) leads to an increased understanding of how different bacterial species maintain asymptomatic colonization or cause disease and may contribute to efforts to mitigate disease.
Chromatin Immunoprecipitation Sequencing Technology Reveals Global Regulatory Roles of Low-Cell-Density Quorum-Sensing Regulator AphA in the Pathogen Vibrio alginolyticus
Authors: Gu Dan , Liu Huan , Yang Zhen , Zhang Yuanxing , Wang Qiyao
Published: August 2016

Quorum sensing (QS) is an important regulatory system in virulence expression and environmental adaptation in bacteria. The master QS regulators (MQSR) LuxR and AphA reciprocally control QS gene expression in vibrios. However, the molecular basis for the regulatory functions of AphA remains undefined. In this study, we characterized its regulatory roles in
Vibrio alginolyticus
, an important zoonotic pathogen causing diseases in marine animals as well as in humans. AphA is involved in the motility ability, biofilm formation, and
in vivo
survival of
V. alginolyticus
. Specifically, AphA is expressed at low-cell-density growth phases. In addition, AphA negatively regulates the expression of the main virulence factor, alkaline serine protease (Asp), through LuxR. Chromatin immunoprecipitation (ChIP) followed by high-throughput DNA sequencing (ChIP-seq) detected 49 enriched loci harboring AphA-binding peaks across the
V. alginolyticus
genome. An AphA-specific binding motif was identified and further confirmed by electrophoretic mobility shift assay (EMSA) and mutagenesis analysis. A quantitative real-time PCR (qRT-PCR) assay further validated the regulation of AphA on these genes. AphA binds directly to the
aphA
promoter and negatively regulates its own expression. Moreover, AphA directly regulates genes encoding adenylate cyclase, anti-σ
D
, FabR, and the small RNA CsrB, revealing versatile regulatory roles of AphA in its physiology and virulence. Furthermore, our data indicated that AphA modulates motility through the coordinated function of LuxR and CsrB. Collectively, the findings of this work contribute to better understanding of the regulatory roles of AphA in QS and non-QS genes.

IMPORTANCE
In this work, we determined that AphA, the master regulator of QS at low cell density, plays essential roles in expression of genes associated with physiology and virulence in
V. alginolyticus
, a Gram-negative pathogen for humans and marine animals. We further uncovered that 49 genes could be directly regulated by AphA and a 19-bp consensus binding sequence was identified. Among the 49 genes, the QS and other non-QS-associated genes were identified to be regulated by AphA. Besides, the small RNA CsrB was negatively regulated by AphA, and AphA regulate motility abilities through both CsrB and LuxR. Taken together, the findings of this study improve our understanding of the complex regulation network of AphA and QS.
The Coordinated Positive Regulation of Topoisomerase Genes Maintains Topological Homeostasis in Streptomyces coelicolor
Authors: Szafran Marcin Jan , Gongerowska Martyna , Gutkowski Paweł , Zakrzewska-Czerwińska Jolanta , Jakimowicz Dagmara
Published: August 2016

Maintaining an optimal level of chromosomal supercoiling is critical for the progression of DNA replication and transcription. Moreover, changes in global supercoiling affect the expression of a large number of genes and play a fundamental role in adapting to stress. Topoisomerase I (TopA) and gyrase are key players in the regulation of bacterial chromosomal topology through their respective abilities to relax and compact DNA. Soil bacteria such as
Streptomyces
species, which grow as branched, multigenomic hyphae, are subject to environmental stresses that are associated with changes in chromosomal topology. The topological fluctuations modulate the transcriptional activity of a large number of genes and in
Streptomyces
are related to the production of antibiotics. To better understand the regulation of topological homeostasis in
Streptomyces coelicolor
, we investigated the interplay between the activities of the topoisomerase-encoding genes
topA
and
gyrBA
. We show that the expression of both genes is supercoiling sensitive. Remarkably, increased chromosomal supercoiling induces the
topA
promoter but only slightly influences
gyrBA
transcription, while DNA relaxation affects the
topA
promoter only marginally but strongly activates the
gyrBA
operon. Moreover, we showed that exposure to elevated temperatures induces rapid relaxation, which results in changes in the levels of both topoisomerases. We therefore propose a unique mechanism of
S. coelicolor
chromosomal topology maintenance based on the supercoiling-dependent stimulation, rather than repression, of the transcription of both topoisomerase genes. These findings provide important insight into the maintenance of topological homeostasis in an industrially important antibiotic producer.

IMPORTANCE
We describe the unique regulation of genes encoding two topoisomerases, topoisomerase I (TopA) and gyrase, in a model
Streptomyces
species. Our studies demonstrate the coordination of topoisomerase gene regulation, which is crucial for maintenance of topological homeostasis.
Streptomyces
species are producers of a plethora of biologically active secondary metabolites, including antibiotics, antitumor agents, and immunosuppressants. The significant regulatory factor controlling the secondary metabolism is the global chromosomal topology. Thus, the investigation of chromosomal topology homeostasis in
Streptomyces
strains is crucial for their use in industrial applications as producers of secondary metabolites.