bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Bacteriophage Mortality on Exposure to Copper
Authors: Li Jinyu , Dennehy John J. 
Published: August 2011

ABSTRACT

Many studies report that copper can be used to control microbial growth, including that of viruses. We determined the rates of copper-mediated inactivation for a wide range of bacteriophages. We used two methods to test the effect of copper on bacteriophage survival. One method involved placing small volumes of bacteriophage lysate on copper and stainless steel coupons. Following exposure, metal coupons were rinsed with lysogeny broth, and the resulting fluid was serially diluted and plated on agar with the corresponding bacterial host. The second method involved adding copper sulfate (CuSO
4
) to bacteriophage lysates to a final concentration of 5 mM. Aliquots were removed from the mixture, serially diluted, and plated with the appropriate bacterial host. Significant mortality was observed among the double-stranded RNA (dsRNA) bacteriophages Φ6 and Φ8, the single-stranded RNA (ssRNA) bacteriophage PP7, the ssDNA bacteriophage ΦX174, and the dsDNA bacteriophage PM2. However, the dsDNA bacteriophages PRD1, T4, and λ were relatively unaffected by copper. Interestingly, lipid-containing bacteriophages were most susceptible to copper toxicity. In addition, in the first experimental method, the pattern of bacteriophage Φ6 survival over time showed a plateau in mortality after lysates dried out. This finding suggests that copper's effect on bacteriophage is mediated by the presence of water.
High-Throughput Workflow for Monitoring and Mining Bioprocess Data and Its Application to Inferring the Physiological Response of Escherichia coli to Perturbations
Authors: Heux Stéphanie , Philippe Benjamin , Portais Jean-Charles 
Published: August 2011

ABSTRACT

Miniaturization and high-throughput screening are currently the focus of emerging research areas such as systems biology and systems biotechnology. A fluorescence-based screening assay for the online monitoring of oxygen and pH and a numerical method to mine the resulting online process data are described. The assay employs commercial phosphorescent oxygen- and pH-sensitive probes in standard 48- or 96-well plates on a plate reader equipped with a shaker. In addition to dual parametric analysis of both pH and oxygen in a single well, the assay allows monitoring of growth, as measured by absorbance. Validation of the assay is presented and compared with commercially available plates equipped with optical sensors for oxygen and pH. By using model-free fitting to the readily available online measurements, the length and rate of each phase such as the duration of lag and transition phase or acidification, growth, and oxygen consumption rates are automatically detected. In total, nine physiological descriptors, which can be used for further statistical and comparison analysis, are extracted from the pH, oxygen partial pressure (pO
2
), and optical density (OD) profiles. The combination of a simple mix-and-measure procedure with an automatic data mining method allows high sample throughput and good reproducibility while providing a physiological state identification and characterization of test cells. As a proof of concept, the utility of the workflow in assessing the physiological response of
Escherichia coli
to environmental and genetic perturbations is demonstrated.
An Extracytoplasmic Function Sigma Factor-Mediated Cell Surface Signaling System in Pseudomonas syringae pv. tomato DC3000 Regulates Gene Expression in Response to Heterologous Siderophores
Authors: Markel Eric , Maciak Charlene , Butcher Bronwyn G. , Myers Christopher R. , Stodghill Paul , Bao Zhongmeng , Cartinhour Sam , Swingle Bryan 
Published: August 2011

ABSTRACT

The diversity of regulatory systems encoded by bacteria provides an indication of the variety of stresses and interactions that these organisms encounter in nature. We have been investigating how the plant pathogen
Pseudomonas syringae
pv. tomato DC3000 responds to iron limitation and have focused on the iron starvation (IS) sigma factors to identify regulon members and to explore the mechanistic details of genetic control for this class of regulators. In the study described in this report, we used chromatin immunoprecipitation paired with high-throughput sequencing (ChIP-Seq) to screen the genome for locations associated with binding of the
P. syringae
IS sigma factor PSPTO_1203. We used multiple methods to demonstrate differential regulation of two genes identified in the ChIP-Seq screen and characterize the promoter elements that facilitate PSPTO_1203-dependent regulation. The genes regulated by PSPTO_1203 encode a TonB-dependent transducer (PSPTO_1206) and a cytoplasmic membrane protein (PSPTO_2145), which is located in the
P. syringae
pyoverdine cluster. Additionally, we identified siderophores that induce the activity of PSPTO_1203 and used this information to investigate the functional components of the signal transduction cascade.
Bacterioopsin-Mediated Regulation of Bacterioruberin Biosynthesis in Halobacterium salinarum
Authors: Dummer Antoinette M. , Bonsall Jessica C. , Cihla Jacob B. , Lawry Stephanie M. , Johnson Gabriela C. , Peck Ronald F. 
Published: August 2011

ABSTRACT

Integral membrane protein complexes consisting of proteins and small molecules that act as cofactors have important functions in all organisms. To form functional complexes, cofactor biosynthesis must be coordinated with the production of corresponding apoproteins. To examine this coordination, we study bacteriorhodopsin (BR), a light-induced proton pump in the halophilic archaeon
Halobacterium salinarum
. This complex consists of a retinal cofactor and bacterioopsin (BO), the BR apoprotein. To examine possible novel regulatory mechanisms linking BO and retinal biosynthesis, we deleted
bop
, the gene that encodes BO.
bop
deletion resulted in a dramatic increase of bacterioruberins, carotenoid molecules that share biosynthetic precursors with retinal. Additional studies revealed that bacterioruberins accumulate in the absence of BO regardless of the presence of retinal or BR, suggesting that BO inhibits bacterioruberin biosynthesis to increase the availability of carotenoid precursors for retinal biosynthesis. To further examine this potential regulatory mechanism, we characterized an enzyme, encoded by the
lye
gene, that catalyzes bacterioruberin biosynthesis. BO-mediated inhibition of bacterioruberin synthesis appears to be specific to the
H. salinarum
lye
-encoded enzyme, as expression of a
lye
homolog from
Haloferax volcanii
, a related archaeon that synthesizes bacterioruberins but lacks opsins, resulted in bacterioruberin synthesis that was not reduced in the presence of BO. Our results provide evidence for a novel regulatory mechanism in which biosynthesis of a cofactor is promoted by apoprotein-mediated inhibition of an alternate biochemical pathway. Specifically, BO accumulation promotes retinal production by inhibiting bacterioruberin biosynthesis.
Cross-talk between Phospho-STAT3 and PLCγ1 Plays a Critical Role in Colorectal Tumorigenesis
Authors: Zhang Peng , Zhao Yiqing , Zhu Xiaofeng , Sedwick David , Zhang Xiaodong , Wang Zhenghe 
Published: August 2011

AbstractHyperphosphorylation at the Y705 residue of signal transducer and activator of transcription 3 (STAT3) is implicated in tumorigenesis of leukemia and some solid tumors. However, its role in the development of colorectal cancer is not well defined. To rigorously test the impact of this phosphorylation on colorectal tumorigenesis, we engineered a STAT3 Y705F knock-in to interrupt STAT3 activity in HCT116 and RKO colorectal cancer cells. These STAT3 Y705F mutant cells fail to respond to cytokine stimulation and grow slower than parental cells. These mutant cells are also greatly diminished in their abilities to form colonies in culture, to exhibit anchorage-independent growth in soft agar, and to grow as xenografts in nude mice. These observations strongly support the premise that STAT3 Y705 phosphorylation is crucial in colorectal tumorigenesis. Although it is generally believed that STAT3 functions as a transcription factor, recent studies indicate that transcription-independent functions of STAT3 also play an important role in tumorigenesis. We show here that wild-type STAT3, but not STAT3 Y705F mutant protein, associates with phospholipase Cγ1 (PLCγ1). PLCγ1 is a central signal transducer of growth factor and cytokine signaling pathways that are involved in tumorigenesis. In STAT3 Y705F mutant colorectal cancer cells, PLCγ1 activity is reduced. Moreover, overexpression of a constitutively active form of PLCγ1 rescues the transformation defect of STAT3 Y705F mutant cells. In aggregate, our study identifies previously unknown cross-talk between STAT3 and the PLCγ signaling pathways that may play a critical role in colorectal tumorigenesis. Mol Cancer Res; 9(10); 1418–28. ©2011 AACR.
Repeated Provocation of Time- and ATP-Induced Early Pulmonary Vein Reconnections After Pulmonary Vein Isolation
Authors: Yamane Teiichi , Matsuo Seiichiro , Date Taro , Lellouche Nicolas , Hioki Mika , Narui Ryosuke , Ito Keiichi , Tanigawa Shin-ichi , Yamashita Seigo , Tokuda Michifumi , Yoshida Hiroshi , Inada Keiichi , Shibayama Kenri , Miyanaga Satoru , Miyazaki Hidekazu , Abe Kunihiko , Sugimoto Ken-ichi , Yoshimura Michihiro 
Published: August 2011

Background—
Recurrence of atrial fibrillation (AF) after successful pulmonary vein isolation (PVI) occurs mainly due to the reconnection of the once isolated PV. Although provocation and elimination of the early pulmonary vein reconnection (EPVR) soon after PVI has been widely performed to improve the outcome, AF recurrence due to subsequent PV reconnections still occurs. In this study, we repeatedly provoked and eliminated the EPVR to determine the appropriate procedural end point.

Methods and Results—

Seventy-five patients with paroxysmal AF underwent PVI. EPVR was provoked by both time and ATP induction every 30 minutes until 90 minutes after the individual isolation of all PVs. The number of reconnected atrio-PV gaps were evaluated and reablated at each provocation step. Although both time- and ATP-dependent EPVR was induced most frequently at 30 minutes after PVI (75 and 76 gaps, respectively), the prevalence of induced EPVR at 60 minutes was still high (64 and 36 gaps induced by time and ATP, respectively). Only a small number of EPVR appeared at 90 minutes after the elimination of all EPVR by 60 minutes (8 gaps,
P
<0.01). During the mean follow-up period of 370 days, 92% of cases were free from AF without antiarrhythmic drugs.

Conclusions—
Provocation and elimination of time- and ATP-induced EPVR not only at 30 minutes but also at 60 minutes is recommended after PVI to improve its efficacy.
Human Ventricular Fibrillation During Global Ischemia and Reperfusion
Authors: Bradley Chris P. , Clayton Richard H. , Nash Martyn P. , Mourad Ayman , Hayward Martin , Paterson David J. , Taggart Peter 
Published: August 2011

Background—
Ischemic ventricular fibrillation in experimental models has been shown to progress through a series of stages. Progression of ischemic VF in the in vivo human heart has not been determined.

Methods and Results—

We studied 10 patients undergoing cardiac surgery. Ventricular fibrillation was induced by burst pacing. After 30 seconds, global myocardial ischemia was induced by aortic cross-clamp and maintained for 2.5 minutes, followed by coronary reflow. Epicardial activity was sampled (1 kHz) with a sock that contained 256 unipolar contact electrodes. Dominant frequencies were calculated with a fast Fourier transform with a moving window. The locations of phase singularities and activation wavefronts were identified at 10-ms intervals. Preischemic (perfused) ventricular fibrillation was maintained by a disorganized mix of large and small wavefronts. During global myocardial ischemia, mean dominant frequencies decreased from 6.4 to 4.7 Hz at a rate of −0.011±0.002 Hz s
−1
(
P
<0.001) and then increased rapidly to 7.4 Hz within 30 seconds of reflow. In contrast, the average number of epicardial phase singularities increased during ischemia from 7.7 to 9.7 at a rate of 0.013±0.005 phase singularities per second (
P
<0.01) and remained unchanged during reflow, at 10.3. The number of wavefronts showed a similar time course to the number of phase singularities.

Conclusions—
In human ventricular fibrillation, we found an increase in complexity of electric activation patterns during global myocardial ischemia, and this was not reversed during reflow despite an increase in activation rate.
Epicardial Ablation for Ventricular Tachycardia
Authors: Della Bella Paolo , Brugada Josep , Zeppenfeld Katja , Merino Jose , Neuzil Petr , Maury Philippe , Maccabelli Giuseppe , Vergara Pasquale , Baratto Francesca , Berruezo Antonio , Wijnmaalen Adrianus P. 
Published: August 2011

Background—
The purpose of this study was to describe the epicardial percutaneous ablation experience of 6 European high-volume ventricular tachycardia (VT) ablation centers.

Methods and Results—
Data from 218 patients with coronary artery disease (CAD, n=85 [39.0%]), idiopathic dilated of patients with idiopathic VT cardiomyopathy (IDCM, n=67 [30.7%]), arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARCD/C, n=13 [6%]), hypertrophic cardiomyopathy (HCM, n=5 [2.3%]), and absence of structural heart disease (n=48 [22%]) undergoing epicardial subxyphoid access for VT ablation were collected. The epicardial approach was attempted as first-line treatment in 78 patients (35.8%). Acute prevention of VT inducibility was obtained in 156 patients (71.6%). There were no procedure-related deaths. Cardiac tamponade occurred in 8 patients, and abdominal hemorrhage in 1 patient. Six patients died of electrical storm recurrence within 48 hours from the procedure. After a mean follow-up of 17.3±18.2 months, 60 patients (31.4%) presented with VT recurrence (39.3% of IDCM patients; 34.7% of CAD patients; 30.8% of ARVD/C patients; 25% of HCM patients; 17.1% of patients with idiopathic VT). Twenty patients (10.4%) died during follow-up (12 of heart failure, 2 of cardiac arrest, and 6 of extracardiac causes).

Conclusions—
In experienced centers, epicardial ablation of VT has an acceptable risk and favorable outcome. In selected patients, it is reasonable to consider as a first-line ablation approach.
Influence of Race on Atrial Fibrillation After Cardiac Surgery
Authors: Rader Florian , Van Wagoner David R. , Ellinor Patrick T. , Gillinov A. Marc , Chung Mina K. , Costantini Otto , Blackstone Eugene H. 
Published: August 2011

Background—
Despite having fewer risk factors for atrial fibrillation (AF), white patients have a greater prevalence of AF in the community than black patients, and a genetic basis has been postulated. However, it is unknown whether occurrence of new-onset AF after cardiac surgery is different in white versus black patients, and secondarily, other non-Caucasian patients.

Methods and Results—

From 1995 through 2005, 20 282 white, 1323 black, and 1919 other non-Caucasian patients in sinus rhythm underwent coronary artery bypass grafting with or without valve surgery. To adjust for clinical and socioeconomic confounders, we performed propensity-adjusted analyses; 7093 white patients (35%) had postoperative AF, compared with 255 (22%) black patients and 550 (29%) other non-Caucasians (
P
<0.0001). Whites were older than black patients, had higher socioeconomic position, and greater left atrial size but were less likely to have hypertension or congestive heart failure. In 847 propensity-matched patient pairs, postoperative AF occurred more frequently in white than in black patients (odds ratio, 1.74; 95% confidence interval, 1.7–1.78). Other than higher occurrence of bradycardia requiring pacing and reintubation in white patients, occurrence of other postoperative complications, hospital mortality, and length of postoperative stay were similar. Age and valvular surgery were the strongest predictors of AF irrespective of race.

Conclusions—
White patients had a markedly higher risk of postoperative AF than black and other non-Caucasian patients. The cause for racial differences of arrhythmic risk is unknown, but a genetic predisposition is plausible. Our results have implications for risk stratification and mechanistic understanding of postoperative AF.
Very Low Risk of Thromboembolic Events in Patients Undergoing Successful Catheter Ablation of Atrial Fibrillation With a CHADS
2
Score ≤3
Authors: Saad Eduardo B. , d'Avila André , Costa Ieda P. , Aryana Arash , Slater Charles , Costa Rodrigo E. , Inácio Luiz A. , Maldonado Paulo , Neto Dario M. , Camiletti Angelina , Camanho Luiz E. , Polanczyk Carisi A. 
Published: August 2011

Background—
Long-term cessation of oral anticoagulation (OAC) after catheter ablation of atrial fibrillation (AF) has been deemed controversial. The safety of this management strategy in patients without recurrent AF and with historically elevated risks for thromboembolism remains largely unknown. In this study, we sought to evaluate the long-term results of OAC cessation after successful catheter ablation of AF.

Methods and Results—

OAC and antiarrhythmic drugs (AADs) were discontinued irrespective of AF type or baseline CHADS
2
(congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack) risk score in 327 patients (mean age, 63±13 years; 79% men) with drug-refractory AF after catheter ablation (mean CHADS
2
score, 1.89±0.95; median, 2.0). Patients with a CHADS
2
score of 2 (45.4%) and 3 (23.2%) accounted for 68.8% of this cohort. In patients with a high risk of recurrence or prior thromboembolic complications, OAC was continued for up to 6 to 12 months postablation and antiplatelet therapy was administered to all patients who maintained sinus rhythm upon OAC interruption. After a follow-up of 46±17 months (range, 13–82 months), 82% remained AF free (off AADs). Significant predictors of late AF recurrence (
P
<0.05) were nonparoxysmal AF (hazard ration [HR], 1.83), female sex (HR, 2.19), age ≥60 years (HR, 1.81), left atrial size >40 mm (HR, 3.52), CHADS
2
score ≥2 (HR, 1.81), and early recurrences (HR, 5.52). No symptomatic ischemic cerebrovascular events were detected during follow-up despite interruption of OAC in 298 (91%) patients and AADs in 293 (89%) patients.

Conclusions—

No significant thromboembolic-related morbidity is observed when AADs and OAC are discontinued after successful catheter ablation of AF in patients with a CHADS
2
score ≤3 who are maintained on antiplatelet therapy during long-term follow-up.
Evaluation of Pulmonary Vein Stenosis After Pulmonary Vein Isolation Using a Novel Circular Mapping and Ablation Catheter (PVAC)
Authors: von Bary Christian , Weber Stefan , Dornia Christian , Eissnert Christoph , Fellner Claudia , Latzin Philipp , Fredersdorf Sabine , Stadler Stefan , Hamer Okka W. 
Published: August 2011

Background—
Pulmonary vein stenosis (PVST) is a well-known complication of pulmonary vein isolation (PVI). Specific anatomically designed ablation catheters for antral PVI have not been evaluated with regard to the incidence of PVST. We investigated the incidence, severity, and characteristics of PVST after PVI with the Pulmonary Vein Ablation Catheter (PVAC) and phased radiofrequency technology.

Methods and Results

A total of 100 patients (55 men) underwent PVI for atrial fibrillation using the PVAC. PVI was guided by selective angiography of each pulmonary vein (PV) in 70 (70%) patients and by reconstructed 3D atriography (ATG) in 30 (30%) patients. Gadolinium-enhanced MRI or multidetector CT was performed in all patients before treatment and 93±78 days after PVI. PVST was classified as follows: insignificant (<25%), mild (25%–50%), moderate (50%–75%), or severe (>75%). A total of 410 PVs were analyzed. Cardiac imaging demonstrated a detectable narrowing of the PV diameter in 23 (23%) patients and in 28 (7%) PVs. In detail, insignificant PVST was observed in 12 (2.9%) PVs, mild PVST in 15 (3.7%), and moderate PVST in 1 (0.2%). No instances of severe PVST were observed. The use of 3D-ATG was associated with a lower incidence of PVST (0.8% [95% CI, 0.0%–2.2%] versus 5.4% [95% CI, 2.7%–8.1%],
P
=0.027).

Conclusions
To our knowledge, this study is the first to report the incidence of PVST using the PVAC. In this regard, the PVAC seems to be safe if used in an experienced center. In addition, the use of 3D-ATG may decrease the risk of PVST.
Intraventricular Conduction Delay in a Standard 12-Lead Electrocardiogram as a Predictor of Mortality in the General Population
Authors: Aro Aapo L. , Anttonen Olli , Tikkanen Jani T. , Junttila M. Juhani , Kerola Tuomas , Rissanen Harri A. , Reunanen Antti , Huikuri Heikki V. 
Published: August 2011

Background—
Prolonged duration of QRS complex in a 12-lead ECG is associated with adverse prognosis in patients with cardiac disease, but its significance is not well established in the general population. In particular, there is a paucity of data on the prognostic significance of nonspecific intraventricular conduction delay in apparently healthy subjects.

Methods and Results—

We evaluated the 12-lead ECGs of 10 899 Finnish middle-aged subjects from the general population (52% of whom were men; mean age 44±8.5 years) between 1966 and 1972 and followed them for 30±11 years. Primary end points were all-cause mortality, cardiac mortality, and arrhythmic death. Prolonged QRS duration was defined as QRS ≥110 ms and intraventricular conduction delay as QRS ≥110 ms, without the criteria of complete or incomplete bundle-branch block. QRS duration ≥110 ms was present in 1.3% (n=147) and intraventricular conduction delay in 0.6% (n=67) of the subjects. Prolonged QRS duration predicted all-cause mortality (multivariate-adjusted relative risk [RR] 1.48; 95% confidence interval [CI] 1.22–1.81;
P
<0.001), cardiac mortality (RR 1.94; CI 1.44–2.63;
P
<0.001), and sudden arrhythmic death (RR 2.14; CI 1.38–3.33;
P
=0.002). Subjects with intraventricular conduction delay had increased all-cause mortality (RR 2.01; CI 1.52–2.66;
P
<0.001), increased cardiac mortality (RR 2.53; CI 1.64–3.90;
P
<0.001), and an elevated risk of arrhythmic death (RR 3.11; CI 1.74–5.54;
P
=0.001). Left bundle-branch block also weakly predicted arrhythmic death (
P
=0.04), but right bundle-branch block was not associated with increased mortality.

Conclusions—
Prolonged QRS duration in a standard 12-lead ECG is associated with increased mortality in a general population, with intraventricular conduction delay being most strongly associated with an increased risk of arrhythmic death.