bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Coenzyme A Biosynthesis in the Hyperthermophilic Bacterium Thermotoga maritima
Authors: Shimosaka Takahiro , Tomita Hiroya , Atomi Haruyuki 
Published: May 2016

ABSTRACT

Regulation of coenzyme A (CoA) biosynthesis in bacteria and eukaryotes occurs through feedback inhibition targeting type I and type II pantothenate kinase (PanK), respectively. In contrast, the activity of type III PanK is not affected by CoA. As the hyperthermophilic bacterium
Thermotoga maritima
harbors only a single type III PanK (
Tm
-PanK), here we examined the mechanisms that regulate CoA biosynthesis in this organism. We first examined the enzyme responsible for the ketopantoate reductase (KPR) reaction, which is the target of feedback inhibition in archaea. A classical KPR homolog was not present on the
T. maritima
genome, but we found a homolog (TM0550) of the ketol-acid reductoisomerase (KARI) from
Corynebacterium glutamicum
, which exhibits KPR activity. The purified TM0550 protein displayed both KPR and KARI activities and was designated
Tm
-KPR/KARI. When
T. maritima
cell extract was subjected to anion-exchange chromatography, the fractions containing high levels of KPR activity also displayed positive signals in a Western blot analysis using polyclonal anti-TM0550 protein antisera, strongly suggesting that
Tm
-KPR/KARI was the major source of KPR activity in the organism. The KPR activity of
Tm
-KPR/KARI was not inhibited in the presence of CoA. We thus examined the properties of
Tm
-PanK and the pantothenate synthetase (
Tm
-PS) of this organism.
Tm
-PS was not affected by CoA. Surprisingly however,
Tm
-PanK was inhibited by CoA, with almost complete inhibition in the presence of 400 μM CoA. Our results suggest that CoA biosynthesis in
T. maritima
is regulated by feedback inhibition targeting PanK, although
Tm
-PanK is a type III enzyme.

IMPORTANCE
Bacteria and eukaryotes regulate the biosynthesis of coenzyme A (CoA) by feedback inhibition targeting type I or type II pantothenate kinase (PanK). The hyperthermophilic bacterium
Thermotoga maritima
harbors a single type III PanK (
Tm
-PanK), previously considered to be unaffected by CoA. By examining the properties of three enzymes involved in CoA biosynthesis in this organism, we found that
Tm
-PanK, although a type III enzyme, is inhibited by CoA. The results provide a feasible explanation of how CoA biosynthesis is regulated in
T. maritima
, which may also apply for other bacteria that harbor only type III PanK enzymes.
Classifying β-Barrel Assembly Substrates by Manipulating Essential Bam Complex Members
Authors: Mahoney Tara F. , Ricci Dante P. , Silhavy Thomas J. 
Published: May 2016

ABSTRACT

The biogenesis of the outer membrane (OM) of
Escherichia coli
is a conserved and vital process. The assembly of integral β-barrel outer membrane proteins (OMPs), which represent a major component of the OM, depends on periplasmic chaperones and the heteropentameric β-barrel assembly machine (Bam complex) in the OM. However, not all OMPs are affected by null mutations in the same chaperones or nonessential Bam complex members, suggesting there are categories of substrates with divergent requirements for efficient assembly. We have previously demonstrated two classes of substrates, one comprising large, low-abundance, and difficult-to-assemble substrates that are heavily dependent on SurA and also Skp and FkpA, and the other comprising relatively simple and abundant substrates that are not as dependent on SurA but are strongly dependent on BamB for assembly. Here, we describe novel mutations in
bamD
that lower levels of BamD 10-fold and >25-fold without altering the sequence of the mature protein. We utilized these mutations, as well as a previously characterized mutation that lowers wild-type BamA levels, to reveal a third class of substrates. These mutations preferentially cause a marked decrease in the levels of multimeric proteins. This susceptibility of multimers to lowered quantities of Bam machines in the cell may indicate that multiple Bam complexes are needed to efficiently assemble multimeric proteins into the OM.

IMPORTANCE
The outer membrane (OM) of Gram-negative bacteria, such as
Escherichia coli
, serves as a selective permeability barrier that prevents the uptake of toxic molecules and antibiotics. Integral β-barrel proteins (OMPs) are assembled by the β-barrel assembly machine (Bam), components of which are conserved in mitochondria, chloroplasts, and all Gram-negative bacteria, including many clinically relevant pathogenic species. Bam is essential for OM biogenesis and accommodates a diverse array of client proteins; however, a mechanistic model that accounts for the selectivity and broad substrate range of Bam is lacking. Here, we show that the assembly of multimeric OMPs is more strongly affected than that of monomeric OMPs when essential Bam complex components are limiting, suggesting that multiple Bam complexes are needed to assemble multimeric proteins.
A cohort study of regional migration and the risks of attempted suicide and violent assault injury
Authors: Yiannakoulias N , Sanchez-Ramirez D , Svenson L W , Voaklander D C 
Published: May 2016

ObjectivesWe study the association between changing residence and risks of attempted suicide and violent assault injury in Alberta, Canada. Our primary objective is to understand whether a change in residence between urban, rural and semiurban areas is associated with increased risk of intentional injury.MethodsStudy subjects are a cohort of residents linked to data on emergency department and inpatient hospital admissions between 1999 and 2010. We used generalised estimating equations to model the effects of changing residence on risk of intentional injury while controlling for the influence of age, sex, socio-economic status, Aboriginal status and history of intentional injury.ResultsChanging residence is associated with an increase in the risk of both attempted suicide and violent assault injury. In the case of attempted suicide, this effect is strongest for persons between 20 and 35 years of age. For violent assault injuries, persons from rural regions that have recently moved to urban regions have higher risk of injuries, and women of rural origin are at higher risk of violent assault injury than women of urban origin.ConclusionsOur findings reveal an association between risk of intentional injuries and change of residence adjusting for geographical differences in injury risk. These findings suggest that intentional injury risk is associated with change in community at intraregional scales and that these populations may benefit from support that helps integrate them into their new communities.
1: COMPARATIVE EFFECT OF SELECTIVE AND NON-SELECTIVE COX-2 INHIBITORS ON LIPID ACCUMULATION IN HUMAN MACROPHAGES
Authors: Kasselman LJ , Voloshyna I , Littlefield MJ , Siegart N , Carsons SE , Gomolin I , De Leon J , Reiss AB 
Published: May 2016

Purpose of StudyIt is the second decade of controversy regarding the cardiovascular (CV) effects of cycloxygenase-2 (COX-2) inhibitors. COX-2 inhibitors possess anti-inflammatory and analgesic effects comparable with conventional non-steroidal anti-inflammatory drugs, but produce fewer gastrointestinal adverse effects. Here we demonstrate that only selective COX-2 inhibitors cause disruption of the delicate balance between cholesterol efflux and influx that leads to lipid overload and macrophage foam cell formation (FCF).Methods UsedTHP-1 human macrophages were incubated with: celecoxib (10 µM, 25 µM); rofecoxib (10 µM, 25 µM); naproxen (10 µM, 25 µM); acetaminophen (0.5 mM, 1 mM)±oxidized low density lipoprotein (oxLDL, 25 µg/ml, 48 h) or 5 µg/ml (Dil)-oxLDL. FCF (% oil red O stained cells) and oxLDL accumulation were determined (fluorescent intensity). Scavenger receptors: CD36, LOX-1, SR-A1 and CXCL16 and cholesterol efflux proteins: ATP-binding cassette transporter (ABC) A1 and ABCG1 were detected in macrophages by QRT-PCR and immunocytochemistry.Summary of ResultsCelecoxib decreased ABCA1 and ABCG1 message in a concentration dependent manner: 68.2±13.36% for ABCA1 and 65.7±13.36% for ABCG1 (control set at 100%, n=6, P<0.01). Neither naproxen nor acetaminophen significantly affected expression of cholesterol efflux proteins. Both specific and nonspecific COX-2 inhibitors had a significant impact on expression of scavenger receptors CD36, LOX-1 and SR-A1–nearly double control (n=6, P<0.05). However, only specific COX-2 inhibitors significantly increased FCF in THP-1 differentiated macrophages (62.2±5.2% for celecoxib and 56.3±3.4% for rofecoxib vs. 33.5±5.1% for untreated cells, P<0.05).ConclusionsHere we report that only specific COX-2 inhibitors might contribute to atherogenesis by promoting lipid overload and lipoprotein accumulation. This may explain, in part, the increased CV risk in patients taking COX-2 inhibitors for extended periods. Despite increased scavenger receptor expression, naproxen and acetaminophen do not impact lipid content, perhaps because efflux pathways remain intact.
Parasympathetic Effects on Heart Rate Recovery after Exercise
Authors: Kannankeril Prince J. , Le Francis K. , Kadish Alan H. , Goldberger Jeffrey J. 
Published: May 2016

BackgroundExercise and its recovery period are associated with increased risk of death relative to sedentary periods. They are also accompanied by dynamic changes in autonomic tone. Little information is available regarding parasympathetic effects during high-intensity exercise and recovery.MethodsTen normal subjects (five women; age 33 ± 2 years) underwent exercise testing on a bicycle ergometer. On day 1, subjects exercised to maximum tolerated workload using a graded protocol with 5 minutes at maximal workload (peak heart rate achieved 174.7 ± 5.4 bpm). On day 2, subjects performed the identical exercise protocol as on day 1; 1 minute into the maximum exercise stage, atropine (0.04 mg/kg) was administered. Heart rate was recorded every minute during exercise, and an electrocardiogram was recorded every minute in recovery for 10 minutes. The parasympathetic effect on heart rate was defined by the difference in heart rate with and without atropine.ResultsThe parasympathetic effect during maximal exercise was 3.4 to 6 bpm (p < .05). During recovery, a large parasympathetic effect on heart rate was noted by 1 minute (22.8 bpm; p < .0002), increased until 4 minutes, and then remained stable until 10 minutes. Despite faster heart rates with parasympathetic blockade, the P-R interval was shorter (p < .002), consistent with a significant parasympathetic effect on the atrioventricular node in recovery. Evaluation of the Q-T-R-R relationship on the 2 days demonstrated significant changes in both the slope (p < .0001) and the intercept (p < .0001), consistent with a modification of ventricular repolarization by parasympathetic tone in recovery.ConclusionThese data indicate that in normal subjects, parasympathetic effects persist during high-intensity exercise and are prominent in the early phases of recovery. These parasympathetic effects may play an important role in prevention of sudden cardiac death during these periods of increased risk.
Ectonucleotidase NTPDase2 Is Selectively Down-Regulated in Biliary Cirrhosis
Authors: Dranoff Jonathan A. , Kruglov Emma A. , Toure Joahd , Braun Norbert , Zimmermann Herbert , Jain Dhanpat , Knowles Aileen F. , Sévigny Jean 
Published: May 2016

BackgroundPortal fibroblasts are newly identified, potentially fibrogenic liver cells that are distinct from hepatic stellate cells. The ectonucleotidase* nucleoside triphosphate diphosphohydrolase 2 (NTPDase2) is restricted to portal fibroblasts in the normal liver. However, the fate of NTPDase2 after bile duct ligation (BDL) is unknown.*Extracellular enzymes that mediate the degradation of adenosine triphosphate (ATP) and other nucleotides.AimsThe aim of this study was to assess the effect of experimental rat and disease-mediated human biliary cirrhosis on NTP-Dase2 expression in the liver.MethodsCirrhosis was induced in experimental rats via BDL and carbon tetrachloride (CCl4) administration. Archived human liver biopsy specimens from normal liver, primary biliary cirrhosis, or hepatitis C cirrhosis were examined. Changes in expression of NTPDase2 were determined using confocal immunofluorescence, immunoblot, and real-time polymerase chain reaction.ResultsConfocal immunofluorescence demonstrated a decrease in NTPDase2 expression after BDL. Immunoblot and real-time polymerase chain reaction demonstrated a decrease in NTPDase2 expression by portal fibroblasts after BDL. No decrease in NTP-Dase2 protein was noted after CCl4 administration, and NTPDase2 messenger ribonucleic acid was markedly up-regulated after CCl4 administration. Confocal immunofluorescence demonstrated a shift of NTPDase2 expression from portal areas to central areas that colocalized with α-smooth muscle actin after CCl4 administration. In human biopsy specimens, NTPDase2 expression was lost in cirrhosis owing to primary biliary cirrhosis, whereas NTPDase2 expression was shifted to bridging fibrous bands in cirrhosis owing to hepatitis C.ConclusionsLoss of NTPDase2 is a common pathway in both rat and human manifestations of biliary cirrhosis. Conversely, in nonbiliary cirrhosis, NTPDase2 is shifted from the portal area to bridging fibrous bands. Elucidations of the mechanisms regulating NTP-Dase2 expression may lead to new therapeutic approaches to fibrotic liver disease.
Intercellular Adhesion Molecule 1 (ICAM-1) Gene Variant Is Associated with Coronary Artery Calcification Independent of Soluble ICAM-1 Levels
Authors: Reilly Muredach P. , Wolfe Megan L. , Dykhouse Jennifer , Reddy Karthik , Localio Russell A. , Rader Daniel J. 
Published: May 2016

BackgroundAlthough circulating levels of soluble intercellular adhesion molecule 1 (sICAM-1) predict cardiovascular events, no studies have examined intercellular adhesion molecule 1 (ICAM-1) gene variants, plasma sICAM-1 levels, and atherosclerosis in the same sample.MethodsWe examined the association of the ICAM-1 K469E gene variant and plasma sICAM-1 with coronary artery calcification (CAC) in 632 asymptomatic subjects, recruited on the basis of a family history of premature cardiovascular disease.ResultsIn age-adjusted ordinal regression, sICAM-1 levels were associated with CAC (odds ratio [OR] [95% confidence interval (CI)] 1.30 [1.04-1.6] per 100 ng/dL sICAM-1; p = .02), but this association was lost after adjusting for traditional risk factors (OR [95% CI] 0.9 [0.69-1.16]). In men, but not women (interaction p = .018), the ICAM-1 K469E GG genotype predicted lower CAC after adjusting for traditional risk factors (OR [95% CI] 0.33 [0.17-0.61]; p = .001) and further controlling for plasma sICAM-1 (OR [95% CI] 0.27 [0.14-0.52]; p < .001).ConclusionsIn a study sample specifically selected for the characteristic of a family history of premature coronary heart disease, ICAM K469E GG was associated with lower CAC scores in men but not women even after controlling for plasma levels of sICAM-1. These studies suggest that ICAM-1 variants may modulate atherosclerosis in humans and provide support for the concept that inflammatory gene polymorphisms may influence atherosclerosis independent of plasma levels of their gene products.
Effects of Carbon Monoxide Poisoning on Neutrophil Responses in Patients Treated with Hyperbaric Oxygen
Authors: Schnittger Vendela , Rosendahl Kerstin , Lind Folke , Palmblad Jan 
Published: May 2016

BackgroundCarbon monoxide (CO) poisoning can cause tissue injury. Neutrophil granulocytes have been proposed to contribute to the injury, which may be ameliorated by hyperbaric oxygen (HBO2) treatment. We sought to assess the relationship between acute CO poisoning and blood neutrophil count, plasma cytokine, and cortisol responses, as well as the mechanism behind the observed beneficiary effects of HBO2 treatment.MethodsEight patients (age 26-82 years) with severe acute CO poisoning were enrolled, concomitant with eight healthy controls (age 27-42 years), in a prospective, controlled, clinical study. The patients were given three HBO2 treatments (2.8 atmospheres absolute, 100 minutes) within the first 24 hours. The controls were given identical simultaneous HBO2treatments. Venous blood samples were taken before and after each treatment.ResultsAt the start of the HBO2 treatment, patients displayed significantly higher blood neutrophil counts (p < .0001) and plasma cortisol levels (p = .020) than controls, but the two groups had similar values for interleukin-8, granulocyte colony-stimulating factor (G-CSF), neutrophil H2O2 generation, and CD16 and CD18 surface expression. During the observation time, neutrophil H2O2 accumulation declined in patients and in controls (p = .031), whereas the up-regulation of CD18 expression increased (p = .002) in both groups. Moreover, G-CSF levels became significantly higher in patients than in controls (p = .015). G-CSF levels also correlated significantly with neutrophil counts.ConclusionCO poisoning was associated with discrete changes of blood neutrophil counts, cortisol, and G-CSF plasma concentrations. HBO2 treatment modulated neutrophil generation of H2O2 and surface expression of CD18. These changes may be part of the cascade of events leading to the sequelae of CO poisoning and their attenuation by HBO2.
The Impact of Asthma Management Guideline Dissemination on the Control of Asthma in the Community
Authors: Cowie Robert L , Underwood Margot F , Mack Sally 
Published: May 2016

OBJECTIVE: To measure the impact of asthma management education on the control of asthma in the community.DESIGN: A cross‐sectional study comparing three communities.SETTING: Three rural communities in southern Alberta.PATIENTS AND METHODS: A population sample of patients with asthma attending a pharmacy to fill a prescription for asthma medication were selected from three communities. Patients were asked to complete a questionnaire relating to their asthma management and control.INTERVENTION: Three levels of asthma management education were provided in the three communities with populations of 6000 to 10,000. The levels of education ranged from standard continuing medical education programs relating to the national asthma guidelines and a visiting asthma nurse educator to the establishment of an asthma clinic and a multiple‐target, intensive education program for health professionals, town leaders, local media, schools and the public. The survey of the population with asthma was conducted approximately one year after the education program had been completed.RESULTS: A total of 327 completed questionnaires were submitted. Analysis showed that there was no significant difference that could be attributed to the intervention in the management of asthma or in the level of asthma control among the patients from the three communities.RESULTS: A total of 327 completed questionnaires were submitted. Analysis showed that there was no significant difference that could be attributed to the intervention in the management of asthma or in the level of asthma control among the patients from the three communities.
Control of Asthma in Canada: Failure to Achieve Guideline Targets
Authors: Chapman Kenneth R , Ernst Pierre , Grenville A , Dewland P , Zimmerman Sabrina 
Published: May 2016

OBJECTIVE: To assess the degree of asthma control achieved by patients with asthma in Canada and to describe the impact of poor asthma control.DESIGN: Population‐based, cross‐sectional telephone interview survey of Canadians with doctor‐diagnosed asthma.SUBJECTS AND METHODS: Random digit dialing was used to identify a representative sample of Canadians with asthma. A total of 801 adults and 200 parents of children aged four to 15 years were interviewed over the telephone. Telephone interviews were also conducted with 266 physicians.RESULTS: Only 24% of patients achieved disease control by meeting the six symptom‐based criteria listed by the 1996 Canadian Asthma Consensus Guidelines as appropriate treatment targets. Fifty‐seven per cent of patients failed to meet two or more of the six control criteria and were considered poorly controlled. Fifty‐one per cent had required urgent care for out of control asthma at least once in the year before the survey. Nonetheless, 91% of patients thought that their asthma was adequately controlled. Physicians shared this optimism: 77% of family physicians and 90% of respirologists believed that they were usually able to achieve optimal asthma control in their patients. Few physicians gauged asthma control by tracking more than one or two symptoms, and just over one‐half (54%) of patients surveyed recalled ever having had a lung function test. One‐half (48%) of patients with poorly controlled asthma who used inhaled steroids did not understand the role of inhaled steroids; onethird (32%) of patients with poorly controlled asthma who used short acting bronchodilators misunderstood the action of quick relief bronchodilators.CONCLUSIONS: The majority of Canadians with asthma suffer from inadequate control of their disease. Suboptimal control of asthma is associated with excess health care use. Inadequate monitoring by physicians and poor patient education may be factors contributing to this problem.
Constitutive Activation of PI3K in Oocyte Induces Ovarian Granulosa Cell Tumors
Authors: Kim So-Youn , Ebbert Katherine , Cordeiro Marilia H. , Romero Megan M. , Whelan Kelly A. , Suarez Adrian A. , Woodruff Teresa K. , Kurita Takeshi 
Published: May 2016

Abstract
Cell–cell interactions play crucial roles in the maintenance of tissue homeostasis, a loss of which often leads to varying diseases, including cancer. Here, we report that uncontrolled PI3K activity within oocytes irreversibly transforms granulosa cells (GC), causing GC tumors (GCT) through perturbed local cell communication. Previously, we reported reproductive phenotypes of transgenic mice, in which expression of constitutively active mutant PI3K was induced in primordial oocytes by Gdf9-iCre. The transgenic mice (Cre+) demonstrated severe ovarian phenotypes, including the overgrowth of excess ovarian follicles and anovulation. Surprisingly, the Cre+ mice became cachectic by postnatal day 80 due to bilateral GCT. Although GCT cells proliferated independently of oocytes, local interactions with mutant PI3K-positive oocytes during early folliculogenesis were essential for the GC transformation. Growing GCT cells expressed high levels of inhibin βA and nuclear SMAD3, and the proliferation rate was positively correlated with a high activin A to inhibin A ratio. These results suggested that the tumor cells stimulated their growth through an activin A autocrine signaling pathway, a hypothesis confirmed by activin A secretion in cultured GCT cells, which proliferated in response. Although communication between the oocyte and surrounding somatic cells is critical for the normal development of ovarian follicles, perturbations in oocyte–GC communication during early folliculogenesis can induce GCT by activating an autocrine growth circuit program in GC. Cancer Res; 76(13); 3851–61. ©2016 AACR.