bluuebunny/crossref_metadata_2025_split huggingface dataset:
Receptor protein tyrosine phosphatase sigma regulates synapse structure, function and plasticity
Authors: Horn Katherine E. , Xu Bin , Gobert Delphine , Hamam Bassam N. , Thompson Katherine M. , Wu Chia‐Lun , Bouchard Jean‐François , Uetani Noriko , Racine Ronald J. , Tremblay Michel L. , Ruthazer Edward S. , Chapman C. Andrew , Kennedy Timothy E. 
Published: April 2012

J. Neurochem. (2012) 122, 147–161.AbstractThe mechanisms that regulate synapse formation and maintenance are incompletely understood. In particular, relatively few inhibitors of synapse formation have been identified. Receptor protein tyrosine phosphatase σ (RPTPσ), a transmembrane tyrosine phosphatase, is widely expressed by neurons in developing and mature mammalian brain, and functions as a receptor for chondroitin sulfate proteoglycans that inhibits axon regeneration following injury. In this study, we address RPTPσ function in the mature brain. We demonstrate increased axon collateral branching in the hippocampus of RPTPσ null mice during normal aging or following chemically induced seizure, indicating that RPTPσ maintains neural circuitry by inhibiting axonal branching. Previous studies demonstrated a role for pre‐synaptic RPTPσ promoting synaptic differentiation during development; however, subcellular fractionation revealed enrichment of RPTPσ in post‐synaptic densities. We report that neurons lacking RPTPσ have an increased density of pre‐synaptic varicosities in vitro and increased dendritic spine density and length in vivo. RPTPσ knockouts exhibit an increased frequency of miniature excitatory post‐synaptic currents, and greater paired‐pulse facilitation, consistent with increased synapse density but reduced synaptic efficiency. Furthermore, RPTPσ nulls exhibit reduced long‐term potentiation and enhanced novel object recognition memory. We conclude that RPTPσ limits synapse number and regulates synapse structure and function in the mature CNS.
Paradoxical Change in Atrial Fibrillation Dominant Frequencies with Baroreflex‐Mediated Parasympathetic Stimulation with Phenylephrine Infusion
Authors: NG JASON , PASSMAN ROD S. , ARORA RISHI , KADISH ALAN H. , GOLDBERGER JEFFREY J. 
Published: April 2012

Baroreflex Response and AF Dominant Frequency. Introduction: Parasympathetic stimulation is known to promote atrial fibrillation (AF) through shortening of atrial refractory periods. We hypothesized that baroreflex‐mediated parasympathetic stimulation via phenylephrine (PE) infusion would increase AF rate as measured by dominant frequency (DF).Methods and Results: The protocol was performed in 27 patients (24 M, 59 ± 1 years old) prior to AF ablation. For 10 patients in AF, PE was infused until systolic blood pressure increased ≥30 mmHg. Electrograms were recorded in the left atrium before and after PE. DFs of each recording were calculated offline. Atrial effective refractory periods (ERPs) were measured before and after PE in 11 patients who were in sinus rhythm during the procedure. DFs were also measured in 6 patients in AF before and after complete parasympathetic blockade with atropine (0.04 mg/kg).PE resulted in increased RR intervals during sinus rhythm (1,170 ± 77 to 1,282 ± 85 ms, P = 0.03) and AF (743 ± 32 to 826 ± 30 ms, P = 0.03), consistent with parasympathetic effect on the sinus and AV nodes, respectively. DFs were decreased by PE in the left atrium (6.2 ± 0.2 to 6.0 ± 0.2 Hz, P = 0.004). Correspondingly, atrial ERPs significantly increased from 218 ± 13 to 232 ± 11 ms (P = 0.04). Atropine resulted in a decreasing trend in DF in the left atrium (5.9 ± 0.1 to 5.8 ± 0.1 Hz, P = 0.07).Conclusions: Despite baroreflex‐mediated parasympathetic effect, PE produced a slowing of AF along with lengthening of ERP, while parasympathetic blockade also slowed DF. It is therefore likely that the direct and indirect adrenergic effects of PE on atrial electrophysiology are more prominent than its parasympathetic effects. (J Cardiovasc Electrophysiol, Vol. 23 pp. 1045‐1050, October 2012)
The impact of intrinsic and extrinsic factors on the job satisfaction of dentists
Authors: Goetz K. , Campbell S.M. , Broge B. , Dörfer C.E. , Brodowski M. , Szecsenyi J. 
Published: April 2012

The Two‐Factor Theory of job satisfaction distinguishes between intrinsic‐motivation (i.e. recognition, responsibility) and extrinsic‐hygiene (i.e. job security, salary, working conditions) factors. The presence of intrinsic‐motivation facilitates higher satisfaction and performance, whereas the absences of extrinsic factors help mitigate against dissatisfaction. The consideration of these factors and their impact on dentists’ job satisfaction is essential for the recruitment and retention of dentists.ObjectivesThe objective of the study is to assess the level of job satisfaction of German dentists and the factors that are associated with it.MethodsThis cross‐sectional study was based on a job satisfaction survey. Data were collected from 147 dentists working in 106 dental practices. Job satisfaction was measured with the 10‐item Warr‐Cook‐Wall job satisfaction scale. Organizational characteristics were measured with two items. Linear regression analyses were performed in which each of the nine items of the job satisfaction scale (excluding overall satisfaction) were handled as dependent variables. A stepwise linear regression analysis was performed with overall job satisfaction as the dependent outcome variable, the nine items of job satisfaction and the two items of organizational characteristics controlled for age and gender as predictors.ResultsThe response rate was 95.0%. Dentists were satisfied with ‘freedom of working method’ and mostly dissatisfied with their ‘income’. Both variables are extrinsic factors. The regression analyses identified five items that were significantly associated with each item of the job satisfaction scale: ‘age’, ‘mean weekly working time’, ‘period in the practice’, ‘number of dentist's assistant’ and ‘working atmosphere’. Within the stepwise linear regression analysis the intrinsic factor ‘opportunity to use abilities’ (β = 0.687) showed the highest score of explained variance (R2 = 0.468) regarding overall job satisfaction.ConclusionsWith respect to the Two‐Factor Theory of job satisfaction both components, intrinsic and extrinsic, are essential for dentists but the presence of intrinsic motivating factors like the opportunity to use abilities has most positive impact on job satisfaction. The findings of this study will be helpful for further activities to improve the working conditions of dentists and to ensure quality of care.
Screening for distant metastases before salvage surgery in patients with recurrent head and neck squamous cell carcinoma: a retrospective case series comparing thoraco‐abdominal CT, positron emission tomography and abdominal ultrasound
Authors: Fakhry N. , Michel J. , Colavolpe C. , Varoquaux A. , Dessi P. , Giovanni A. 
Published: April 2012

Clin. Otolaryngol. 2012, 37, 197–206Objectives:  To evaluate the role of 18‐fluoro‐deoxy‐d‐glucose (FDG)‐positron emission tomography (PET) scan for detecting distant metastases in the preoperative assessment of patients with recurrent head and neck squamous cell carcinoma (HNSCC).Design:  Retrospective study.Setting:  University Teaching Hospital.Main outcome measures:  Thirty‐seven consecutive patients who presented, between April 2008 and April 2010, a local and/or regional recurrence of head and neck squamous cell carcinoma after treatment with radio‐chemotherapy were studied. The work‐up included thoraco‐abdominal computed tomography (CT), fluoro‐deoxy‐d‐glucose‐positron emission tomography scan and abdominal ultrasound. The imaging results, when positive, were compared to histology or cytology (conducted during targeted examinations, for example, fiberoptic oesophago‐gastro‐duodenal search, colonoscopy, bronchoscopy, liver biopsy) or targeted imaging examination (Abdominal MRI, sonography) combined with clinical follow‐up. All patients were followed‐up for at least 6 months. Positron emission tomography performances were then analysed and compared with those of conventional imaging for detecting distant metastases.Results:  Among the 37 patients, 9 (24%) had visceral metastases. The sensitivity, specificity, positive predictive value and negative predictive value for detecting metastasis or second primary were, respectively, 100%, 94%, 86% and 100% for CT and 92%, 87%, 74% and 97% for positron emission tomography. Computed tomography and positron emission tomography were strictly concordant in 32/37 (86%) of cases. No false‐negative result was found for CT, while we found one case of false‐negative positron emission tomography. The number of false‐positive results was two for CT and four for positron emission tomography.Conclusions:  From our study, positron emission tomography does not appear to offer a first‐choice technique for the detection of metastases before salvage surgery as CT detected all lesions visible on positron emission tomography.
Prevalence of Gastroesophageal Reflux Disease in Premature Calves
Authors: Guzelbektes H. , Coskun A. , Ok M. , Aydogdu U. , Sen I. 
Published: April 2012

BackgroundGastroesophageal reflux (GER) is the presence of gastric contents proximal to the stomach. Pathologic consequences secondary toGERare termed gastroesophageal reflux disease (GERD).ObjectivesThe purpose of this study was to determine the prevalence ofGERandGERDin premature calves by endoscopic examination.AnimalsTen healthy and 51 premature calves were included in the study. All premature calves also had respiratory distress syndrome.MethodsEsophagoscopy of premature calves was conducted by fiber optic endoscopy. Abnormalities such as increased saliva, hyperemia, hemorrhage, petechiae, presence of abomasal content in the esophagus, and relaxation of the lower esophageal sphincter (LES) were evaluated by endoscopy.ResultsThe prevalence ofGERDandGERin the premature calves was 55 and 67%, respectively. Hyperemia and hyperemia with hemorrhage or petechiation of the esophageal mucosa were determined by endoscopic examination.Hyperemia was commonly observed in the distal esophageal mucosa, although a few hyperemic areas also were observed in other portions of the esophagus. In addition to these abnormalities,LESrelaxation, abomasal fluid in the distal esophagus, abomasal content in the esophagus, and increased saliva also were observed in premature calves withGER.ConclusionsThe prevalence of bothGER(67%) andGERD(55%) in premature calves was high in the study. Endoscopy provides a practical, rapid, noninvasive, and reasonably accurate method for determining the presence ofGERandGERDin premature calves.
Precise Manipulation of the Clostridium difficile Chromosome Reveals a Lack of Association between the
tcdC
Genotype and Toxin Production
Authors: Cartman Stephen T. , Kelly Michelle L. , Heeg Daniela , Heap John T. , Minton Nigel P. 
Published: April 2012

ABSTRACT

Clostridium difficile
causes a potentially fatal diarrheal disease through the production of its principal virulence factors, toxin A and toxin B. The
tcdC
gene is thought to encode a negative regulator of toxin production. Therefore, increased toxin production, and hence increased virulence, is often inferred in strains with an aberrant
tcdC
genotype. This report describes the first allele exchange system for precise genetic manipulation of
C. difficile
, using the
codA
gene of
Escherichia coli
as a heterologous counterselection marker. It was used to systematically restore the Δ117 frameshift mutation and the 18-nucleotide deletion that occur naturally in the
tcdC
gene of
C. difficile
R20291 (PCR ribotype 027). In addition, the naturally intact
tcdC
gene of
C. difficile
630 (PCR ribotype 012) was deleted and then subsequently restored with a silent nucleotide substitution, or “watermark,” so the resulting strain was distinguishable from the wild type. Intriguingly, there was no association between the
tcdC
genotype and toxin production in either
C. difficile
R20291 or
C. difficile
630. Therefore, an aberrant
tcdC
genotype does not provide a broadly applicable rationale for the perceived notion that PCR ribotype 027 strains are “high-level” toxin producers. This may well explain why several studies have reported that an aberrant
tcdC
gene does not predict increased toxin production or, indeed, increased virulence.
Emergence of Atypical Mycoplasma agalactiae Strains Harboring a New Prophage and Associated with an Alpine Wild Ungulate Mortality Episode
Authors: Tardy Florence , Baranowski Eric , Nouvel Laurent-Xavier , Mick Virginie , Manso-Silvàn Lucía , Thiaucourt François , Thébault Patricia , Breton Marc , Sirand-Pugnet Pascal , Blanchard Alain , Garnier Alexandre , Gibert Philippe , Game Yvette , Poumarat François , Citti Christine 
Published: April 2012

ABSTRACT

The bacterium
Mycoplasma agalactiae
is responsible for contagious agalactia (CA) in small domestic ruminants, a syndrome listed by the World Organization for Animal Health and responsible for severe damage to the dairy industry. Recently, we frequently isolated this pathogen from lung lesions of ibexes during a mortality episode in the French Alps. This situation was unusual in terms of host specificity and tissue tropism, raising the question of
M. agalactiae
emergence in wildlife. To address this issue, the ibex isolates were characterized using a combination of approaches that included antigenic profiles, molecular typing, optical mapping, and whole-genome sequencing. Genome analyses showed the presence of a new, large prophage containing 35 coding sequences (CDS) that was detected in most but not all ibex strains and has a homolog in
Mycoplasma conjunctivae
, a species causing keratoconjunctivitis in wild ungulates. This and the presence in all strains of large integrated conjugative elements suggested highly dynamic genomes. Nevertheless,
M. agalactiae
strains circulating in the ibex population were shown to be highly related, most likely originating from a single parental clone that has also spread to another wild ungulate species of the same geographical area, the chamois. These strains clearly differ from strains described in Europe so far, including those found nearby, before CA eradication a few years ago. While
M. agalactiae
pathogenicity in ibexes remains unclear, our data showed the emergence of atypical strains in Alpine wild ungulates, raising the question of a role for the wild fauna as a potential reservoir of pathogenic mycoplasmas.
Shifts in Identity and Activity of Methanotrophs in Arctic Lake Sediments in Response to Temperature Changes
Authors: He Ruo , Wooller Matthew J. , Pohlman John W. , Quensen John , Tiedje James M. , Leigh Mary Beth 
Published: April 2012

ABSTRACT

Methane (CH
4
) flux to the atmosphere is mitigated via microbial CH
4
oxidation in sediments and water. As arctic temperatures increase, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is important to predicting future CH
4
emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), and pyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°C, and 21°C) in sediments (to a depth of 25 cm) sampled from Lake Qalluuraq on the North Slope of Alaska. CH
4
oxidation activity was measured in microcosm incubations containing sediments at all temperatures, with the highest CH
4
oxidation potential of 37.5 μmol g
−1
day
−1
in the uppermost (depth, 0 to 1 cm) sediment at 21°C after 2 to 5 days of incubation. Q-PCR of
pmoA
and of the 16S rRNA genes of type I and type II methanotrophs, and pyrosequencing of 16S rRNA genes in
13
C-labeled DNA obtained by SIP demonstrated that the type I methanotrophs
Methylobacter
,
Methylomonas
, and
Methylosoma
dominated carbon acquisition from CH
4
in the sediments. The identity and relative abundance of active methanotrophs differed with the incubation temperature. Methylotrophs were also abundant in the microbial community that derived carbon from CH
4
, especially in the deeper sediments (depth, 15 to 20 cm) at low temperatures (4°C and 10°C), and showed a good linear relationship (
R
= 0.82) with the relative abundances of methanotrophs in pyrosequencing reads. This study describes for the first time how methanotrophic communities in arctic lake sediments respond to temperature variations.
Two Systems for Targeted Gene Deletion in Coxiella burnetii
Authors: Beare Paul A. , Larson Charles L. , Gilk Stacey D. , Heinzen Robert A. 
Published: April 2012

ABSTRACT

Coxiella burnetii
is a ubiquitous zoonotic bacterial pathogen and the cause of human acute Q fever, a disabling influenza-like illness.
C. burnetii
's former obligate intracellular nature significantly impeded the genetic characterization of putative virulence factors. However, recent host cell-free (axenic) growth of the organism has enabled development of shuttle vector, transposon, and inducible gene expression technologies, with targeted gene inactivation remaining an important challenge. In the present study, we describe two methods for generating targeted gene deletions in
C. burnetii
that exploit pUC/ColE1
ori
-based suicide plasmids encoding
sacB
for positive selection of mutants. As proof of concept,
C. burnetii
dotA and
dotB
, encoding structural components of the type IVB secretion system (T4BSS), were selected for deletion. The first method exploited Cre-
lox-
mediated recombination. Two suicide plasmids carrying different antibiotic resistance markers and a
loxP
site were integrated into 5′ and 3′ flanking regions of
dotA
. Transformation of this strain with a third suicide plasmid encoding Cre recombinase resulted in the deletion of
dotA
under sucrose counterselection. The second method utilized a loop-in/loop-out strategy to delete
dotA
and
dotB.
A single suicide plasmid was first integrated into 5′ or 3′ target gene flanking regions. Resolution of the plasmid cointegrant by a second crossover event under sucrose counterselection resulted in gene deletion that was confirmed by PCR and Southern blot. Δ
dotA
and Δ
dotB
mutants failed to secrete T4BSS substrates and to productively infect host cells. The repertoire of
C. burnetii
genetic tools now allows ready fulfillment of molecular Koch's postulates for suspected virulence genes.
Influence of Salinity on the Bacterial Community Composition in Lake Bosten, a Large Oligosaline Lake in Arid Northwestern China
Authors: Tang Xiangming , Xie Guijuan , Shao Keqiang , Sai·Bayartu  , Chen Yuangao , Gao Guang 
Published: April 2012

ABSTRACT

Salinity was found to be the dominating contributor controlling bacterial community composition (BCC) and the abundance of
Betaproteobacteria
in the oligosaline Lake Bosten. The high percentage of unclassified bacteria inhabiting this unique habitat highlights the potential ecological importance of BCC in the early stage of lake salinization and eutrophication.
Infections and Coinfections of Questing Ixodes ricinus Ticks by Emerging Zoonotic Pathogens in Western Switzerland
Authors: Lommano Elena , Bertaiola Luce , Dupasquier Christèle , Gern Lise 
Published: April 2012

ABSTRACT

In Europe,
Ixodes ricinus
is the vector of many pathogens of medical and veterinary relevance, among them
Borrelia burgdorferi
sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like
Rickettsia
spp.,
Babesia
spp., “
Candidatus
Neoehrlichia mikurensis,” and
Anaplasma phagocytophilum
in questing ticks. In this study, questing nymph and adult
I. ricinus
ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of
B. burgdorferi
sensu lato,
Rickettsia
spp.,
Babesia
spp., “
Candidatus
Neoehrlichia mikurensis,” and
A. phagocytophilum. B. burgdorferi
sensu lato,
Rickettsia
spp., and “
Candidatus
Neoehrlichia mikurensis” were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively.
Babesia
- and
A. phagocytophilum
-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like
Borrelia spielmanii
,
Borrelia lusitaniae
, and
Rickettsia monacensis
, were identified. Infections with more than one pathogenic species, involving mostly
Borrelia
spp. and
Rickettsia helvetica
, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in
I. ricinus
in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite.
Centromere Binding and Evolution of Chromosomal Partition Systems in the Burkholderiales
Authors: Passot Fanny M. , Calderon Virginie , Fichant Gwennaele , Lane David , Pasta Franck 
Published: April 2012

ABSTRACTHow split genomes arise and evolve in bacteria is poorly understood. Since each replicon of such genomes encodes a specific partition (Par) system, the evolution of Par systems could shed light on their evolution. The cystic fibrosis pathogenBurkholderia cenocepaciahas three chromosomes (c1, c2, and c3) and one plasmid (pBC), whose compatibility depends on strictly specific interactions of the centromere sequences (parS) with their cognate binding proteins (ParB). However, the Par systems ofB. cenocepaciac2, c3, and pBC share many features, suggesting that they arose within an extended family. Database searching revealed seven subfamilies of Par systems like those ofB. cenocepacia. All are from plasmids and secondary chromosomes of theBurkholderiales, which reinforces the proposal of an extended family. The subfamily of the Par system ofB. cenocepaciac3 includes plasmid variants withparSsequences divergent from that of c3. Using electrophoretic mobility shift assay (EMSA), we found that ParB-c3 binds specifically to centromeres of these variants, despite high DNA sequence divergence. We suggest that the Par system ofB. cenocepaciac3 has preserved the features of an ancestral system. In contrast, these features have diverged variably in the plasmid descendants. One such descendant is found both inRalstonia pickettii12D, on a free plasmid, and inRalstonia pickettii12J, on a plasmid integrated into the main chromosome. These observations suggest that we are witnessing a plasmid-chromosome interaction from which a third chromosome will emerge in a two-chromosome species.
Iron Regulates Expression of Bacillus cereus Hemolysin II via Global Regulator Fur
Authors: Sineva Elena , Shadrin Andrey , Rodikova Ekaterina A. , Andreeva-Kovalevskaya Zhanna I. , Protsenko Alexey S. , Mayorov Sergey G. , Galaktionova Darya Yu , Magelky Erica , Solonin Alexander S. 
Published: April 2012

ABSTRACT

The capacity of pathogens to respond to environmental signals, such as iron concentration, is key to bacterial survival and establishment of a successful infection.
Bacillus cereus
is a widely distributed bacterium with distinct pathogenic properties. Hemolysin II (HlyII) is one of its pore-forming cytotoxins and has been shown to be involved in bacterial pathogenicity in a number of cell and animal models. Unlike many other
B. cereus
pathogenicity factors, HlyII is not regulated by pleiotropic transcriptional regulator PlcR but is controlled by its own regulator, HlyIIR. Using a combination of
in vivo
and
in vitro
techniques, we show that
hlyII
expression is also negatively regulated by iron by the global regulator Fur via direct interaction with the
hlyII
promoter. DNase I footprinting and
in vitro
transcription experiments indicate that Fur prevents RNA polymerase binding to the
hlyII
promoter. HlyII expression profiles demonstrate that both HlyIIR and Fur regulate HlyII expression in a concerted fashion, with the effect of Fur being maximal in the early stages of bacterial growth. In sum, these results show that Fur serves as a transcriptional repressor for
hlyII
expression.