bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of GTP cyclohydrolase I expression by orphan receptor Nurr1 in cell culture andin vivo
Authors: Gil Minchan , McKinney Cushla , Lee Mi Kyeong , Eells Jeffrey B. , Phyillaier Marcia A. , Nikodem Vera M. 
Published: January 2007

AbstractNurr1 is an orphan nuclear transcription factor essential for the terminal differentiation of dopamine (DA) neurons in the ventral midbrain (VM). To identify the Nurr1‐target genes, we carried out microarray and quantitative real‐time PCR analyses of Nurr1 null and wild‐type mice in VM at embryonic day (E) 12.5 and shortly after birth (P0). In addition to the absence of mRNAs of DA synthesizing enzymes, the guanosine 5′‐triphosphate (GTP) cyclohydrolase I (GTPCH) was also substantially reduced in the VM of Nurr1‐null mice. GTPCH is the first enzyme in the synthesis pathway of tetrahydrobiopterin (BH4), an essential cofactor for tyrosine hydroxylase in DA synthesis. In the mouse, Nurr1 and GTPCH mRNA were first detected at E10.5, and GTPCH transcription paralleled that of Nurr1. Small interfering RNA targeted against Nurr1 decreases GTPCH expression in MC3T3‐E1 osteoblasts in cell culture. Cotransfection of Nurr1 and the GTPCH‐luciferase (luc) reporter increased the luc activity by about threefold in N2A cells. Additional analysis using 5′‐deletions and mutants revealed that Nurr1 activates GTPCH transcription indirectly through the proximal promoter region, in the absence of the nerve growth factor‐induced clone B (NGFI‐B) responsive element‐like sites, similarly, as recently reported for DA transporter regulation by Nurr1.
Metabotropic glutamate receptor 3 protects neurons from glucose‐induced oxidative injury by increasing intracellular glutathione concentration
Authors: Berent‐Spillson Alison , Russell James W. 
Published: January 2007

AbstractHigh glucose concentrations cause oxidative injury and programmed cell death in neurons, and can lead to diabetic neuropathy. Activating the type 3 metabotropic glutamate receptor (mGluR3) prevents glucose‐induced oxidative injury in dorsal root ganglion neurons co‐cultured with Schwann cells. To determine the mechanisms of protection, studies were performed in rat dorsal root ganglion neuron–Schwann cell co‐cultures. The mGluR3 agonist 2R,4R‐4‐aminopyrrolidine‐2,4‐dicarboxylate prevented glucose‐induced inner mitochondrial membrane depolarization, reactive oxygen species accumulation, and programmed cell death, and increased glutathione (GSH) concentration in co‐cultured neurons and Schwann cells, but not in neurons cultured without Schwann cells. Protection was diminished in neurons treated with the GSH synthesis inhibitor l‐buthionine‐sulfoximine, suggesting that mGluR‐mediated protection requires GSH synthesis. GSH precursors and the GSH precursor GSH‐ethyl ester also protected neurons from glucose‐induced injury, indicating that GSH synthesis in Schwann cells, and transport of reaction precursors to neurons, may underlie mGluR‐mediated neuroprotection. These results support the conclusions that activating glial mGluR3 protects neurons from glucose‐induced oxidative injury by increasing free radical scavenging and stabilizing mitochondrial function, through increased GSH antioxidant defense.
An audit to assess the outcome of a 1‐day acupuncture course for dentists
Authors: Rosted P. , Carrotte P. 
Published: January 2007

Objective: The principal author has, during the last 4 years, given 45 1‐day courses in acupuncture involving 450 dentists arranged under the umbrella of continuous post‐graduate dental education. There is a paucity of evidence in the published dental literature regarding the outcomes after such courses, and the objective of this work was to analyse the outcome after a 1‐day acupuncture course.Materials and methods: In co‐operation with the individual post‐graduate centres, a questionnaire was posted to all participants to ascertain whether; (a) the dentist has taken up acupuncture; (b) how often acupuncture was used; (c) any reasons for not incorporating acupuncture into the daily practice. To further evaluate the quality of the course, the following questions were addressed; (d) overall rating of the course; (e) the relevance of the course, assessed on a scale from 1 to 6 (1, highly unfavourable; 6, very high favourable).Main outcome: A total of 209 (51.6%) questionnaires were returned, although 15 (3.7%) were subsequently excluded. The male:female ratio of respondents was 3:2, with an average age of 42 and 19 years of experience in dental practice. As many as 46% of respondents had incorporated acupuncture into their practice and 19% reported using acupuncture several times a month. The conditions treated were control of the gag reflex, stress management, sinusitis, headache and facial pain. The main reasons for not taking up acupuncture was ‘the dentist never actually got round to starting’ (83%) and lack of appropriate patients (60%).Regarding the evaluation of the course, the assessment forms were obtained from 47% of the participants. Participants from all centres rated the course in the top end, 5.3 of 6.0 possible.
Validity and reliability of patient satisfaction questionnaires in a dental school in Japan
Authors: Imanaka Masahiro , Nomura Yoshiaki , Tamaki Yoh , Akimoto Naotake , Ishikawa Chieko , Takase Hideyo , Ishii Hiroaki , Yamachika Shigeo , Noda Koji , Ide Masamichi , Yamamoto Ken , Kokubo Yuji , Seto Kanichi 
Published: January 2007

Purpose:  The purpose of this study was to construct questionnaires for the dental school setting from freely given patient answers with the aid of text mining, and to confirm the structure, reliability and validity of the questionnaires.Methods:  Using these questionnaires, we carried out a survey of the satisfaction of patients treated at the Dental Hospital of the Tsurumi University School of Dental Medicine. A total of 3394 patients participated in the study. To confirm the reliability of inter‐item correlations and construct validity, factor analysis was carried out, and items belonging to each factor and Cronbach's alpha coefficients were calculated.Results:  Four factors were extracted and 64.0% of the variance was explained by these four factors. All correlation coefficients were >0.85. These four factors were: ‘Treatment’, ‘Communication’, ‘Facilities’ and ‘Appearances’. From structural equation modelling, we determined that overall satisfaction was >0.75 and was statistically significant.Conclusion:  The questionnaires used in this study are useful for measuring patient satisfaction in the dental school hospital setting.
In Vitro Inhibition of
Streptococcus mutans
Biofilm Formation on Hydroxyapatite by Subinhibitory Concentrations of Anthraquinones
Authors: Coenye Tom , Honraet Kris , Rigole Petra , Jimenez Pol Nadal , Nelis Hans J. 
Published: January 2007

ABSTRACT

We report that certain anthraquinones (AQs) reduce
Streptococcus mutans
biofilm formation on hydroxyapatite at concentrations below the MIC. Although AQs are known to generate reactive oxygen species, the latter do not underlie the observed effect. Our results suggest that AQs inhibit
S. mutans
biofilm formation by causing membrane perturbation.
Resistance to Glycopeptide Antibiotics in the Teicoplanin Producer Is Mediated by
van
Gene Homologue Expression Directing the Synthesis of a Modified Cell Wall Peptidoglycan
Authors: Beltrametti Fabrizio , Consolandi Arianna , Carrano Lucia , Bagatin Francesca , Rossi Roberta , Leoni Livia , Zennaro Elisabetta , Selva Enrico , Marinelli Flavia 
Published: January 2007

ABSTRACT

Glycopeptide resistance has been studied in detail in enterococci and staphylococci. In these microorganisms, high-level resistance is achieved by replacing the C-terminal
d
-alanyl-
d
-alanine of the nascent peptidoglycan with
d
-alanyl-
d
-lactate or
d
-alanyl-
d
-serine, thus reducing the affinities of glycopeptides for cell wall targets. Reorganization of the cell wall is directed by the expression of the
van
gene clusters. The identification of
van
gene homologs in the genomes of several glycopeptide-producing actinomycetes suggests the involvement of a similar self-resistance mechanism to avoid suicide. This report describes a comprehensive study of self-resistance in
Actinoplanes teichomyceticus
ATCC 31121, the producer of the clinically relevant glycopeptide teicoplanin.
A. teichomyceticus
ATCC 31121 showed a MIC of teicoplanin of 25 μg/ml and a MIC of vancomycin of 90 μg/ml during vegetative growth. The
vanH
,
vanA
, and
vanX
genes of
A. teichomyceticus
were found to be organized in an operon whose transcription was constitutive. Analysis of the UDP-linked peptidoglycan precursors revealed the presence of UDP-glycomuramyl pentadepsipeptide terminating in
d
-alanyl-
d
-lactate. No trace of precursors ending in
d
-alanyl-
d
-alanine was detected. Thus, the
van
gene complex was transcribed and expressed in the genetic background of
A. teichomyceticus
and conferred resistance to vancomycin and teicoplanin through the modification of cell wall biosynthesis. During teicoplanin production (maximum productivity, 70 to 80 μg/ml), the MIC of teicoplanin remained in the range of 25 to 35 μg/ml. Teicoplanin-producing cells were found to be tolerant to high concentrations of exogenously added glycopeptides, which were not bactericidal even at 5,000 μg/ml.
Population Structure and Resistance Genes in Antibiotic-Resistant Bacteria from a Remote Community with Minimal Antibiotic Exposure
Authors: Pallecchi Lucia , Lucchetti Chiara , Bartoloni Alessandro , Bartalesi Filippo , Mantella Antonia , Gamboa Herlan , Carattoli Alessandra , Paradisi Franco , Rossolini Gian Maria 
Published: January 2007

ABSTRACT

In a previous study, we detected unexpectedly high levels of acquired antibiotic resistance in commensal
Escherichia coli
isolates from a remote Guaraní Indian (Bolivia) community with very low levels of antibiotic exposure and limited exchanges with the exterior. Here we analyzed the structure of the resistant
E. coli
population from that community and the resistance mechanisms. The
E. coli
population (113 isolates from 72 inhabitants) showed a high degree of genetic heterogeneity, as evidenced by phylogenetic grouping (77% group A, 10% group B1, 8% group D, 5% group B2) and genotyping by randomly amplified polymorphic DNA (RAPD) analysis (44 different RAPD types). The acquired resistance genes were always of the same types as those found in antibiotic-exposed settings [
bla
TEM
,
bla
PSE-1
,
catI
,
cmlA6
,
tet
(A),
tet
(B),
dfrA1
,
dfrA7
,
dfrA8
,
dfrA17
,
sul1
,
sul2
,
aphA1
,
aadA1
,
aadA2
,
aadA5
,
aadB
, and
sat-1
]. Class 1 and class 2 integrons were found in 12% and 4% of the isolates, respectively, and harbored arrays of gene cassettes similar to those already described. The cotransferability of multiple-resistance traits was observed from selected isolates and was found to be associated with resistance conjugative plasmids of the F, P, and N types. Overall, these data suggest that the resistance observed in this remote community is likely the consequence of the dissemination of resistant bacteria and resistance genes from antibiotic-exposed settings (rather than of an independent in situ selection) which involved both the clonal expansion of resistant strains and the horizontal transfer/recombination of mobile genetic elements harboring resistance genes.
Increased Genome Instability in
Escherichia coli lon
Mutants: Relation to Emergence of Multiple-Antibiotic-Resistant (Mar) Mutants Caused by Insertion Sequence Elements and Large Tandem Genomic Amplifications
Authors: Nicoloff Hervé , Perreten Vincent , Levy Stuart B. 
Published: January 2007

ABSTRACT

Thirteen spontaneous multiple-antibiotic-resistant (Mar) mutants of
Escherichia coli
AG100 were isolated on Luria-Bertani (LB) agar in the presence of tetracycline (4 μg/ml). The phenotype was linked to insertion sequence (IS) insertions in
marR
or
acrR
or unstable large tandem genomic amplifications which included
acrAB
and which were bordered by IS
3
or IS
5
sequences. Five different
lon
mutations, not related to the Mar phenotype, were also found in 12 of the 13 mutants. Under specific selective conditions, most drug-resistant mutants appearing late on the selective plates evolved from a subpopulation of AG100 with
lon
mutations. That the
lon
locus was involved in the evolution to low levels of multidrug resistance was supported by the following findings: (i) AG100 grown in LB broth had an important spontaneous subpopulation (about 3.7 × 10
−4
) of
lon
::IS
186
mutants, (ii) new
lon
mutants appeared during the selection on antibiotic-containing agar plates, (iii)
lon
mutants could slowly grow in the presence of low amounts (about 2× MIC of the wild type) of chloramphenicol or tetracycline, and (iv) a
lon
mutation conferred a mutator phenotype which increased IS transposition and genome rearrangements. The association between
lon
mutations and mutations causing the Mar phenotype was dependent on the medium (LB versus MacConkey medium) and the antibiotic used for the selection. A previously reported unstable amplifiable high-level resistance observed after the prolonged growth of Mar mutants in a low concentration of tetracycline or chloramphenicol can be explained by genomic amplification.
The Anti-Trypanosoma cruziActivity of Posaconazole in a Murine Model of Acute Chagas' Disease Is Less Dependent on Gamma Interferon than That of Benznidazole
Authors: Ferraz Marcela L. , Gazzinelli Ricardo T. , Alves Rosana O. , Urbina Julio A. , Romanha Alvaro J. 
Published: January 2007

ABSTRACTWe have investigated the influences of gamma interferon (IFN-γ) and interleukin-12 (IL-12) on the efficacy of posaconazole (POS) treatment of acute experimental infections withTrypanosoma cruzi; the standard drug, benznidazole (BZ), was used as a positive control. Wild-type (WT) mice infected withT. cruziand treated with POS or BZ had no parasitemia, 100% survival, and cure rates of 86 to 89%. IFN-γ-knockout (KO) mice infected withT. cruziand treated with BZ controlled the infection during treatment but relapsed after the drug pressure ceased and had 0% survival, while those receiving POS better controlled the infection after the end of treatment and had 70% survival (P< 0.0001 compared to the results for both untreated and BZ-treated animals). IL-12-KO mice infected and treated with POS or BZ had intermediate results, displaying enhanced parasitemia, decreased survival (77 to 83%), and reduced cure rates (35 to 39%) compared with those of the WT animals. Our results demonstrate that either IFN-γ or IL-12 deficiency reduces the efficacy of POS or BZ in this experimental model but also indicate that the anti-T. cruziactivity of POS is much less dependent on the activity of IFN-γ than that of BZ is.
Daptomycin Susceptibility of Unusual Gram-Positive Bacteria: Comparison of Results Obtained by the Etest and the Broth Microdilution Method
Authors: Huang Yu-Tsung , Liao Chun-Hsing , Teng Lee-Jeng , Hsueh Po-Ren 
Published: January 2007

ABSTRACT

MICs of daptomycin, linezolid, and vancomycin against 212 isolates, including
Listeria monocytogenes
and
Pediococcus
,
Leuconostoc
,
Rhodococcus
, and
Nocardia
spp., were determined by the broth microdilution method; daptomycin MICs were also determined by the Etest. Except with those for
Leuconostoc
spp., daptomycin Etest MICs showed >90% agreement with MICs obtained by the broth microdilution method.
Universal In Vitro Antifungal Resistance of Genetic Clades of the
Fusarium solani
Species Complex
Authors: Azor Mónica , Gené Josepa , Cano Josep , Guarro Josep 
Published: January 2007

ABSTRACT

Eleven antifungal drugs were tested against representative isolates of the four phylogenetic clades of the
Fusarium solani
species complex obtained in a multilocus sequence analysis. They all showed very poor activity, with no differences among the clades. Amphotericin B was the most active drug.
Survey of Genomic Diversity among
Enterococcus faecalis
Strains by Microarray-Based Comparative Genomic Hybridization
Authors: Aakra Ågot , Nyquist O. Ludvig , Snipen Lars , Reiersen Turid S. , Nes Ingolf F. 
Published: January 2007

ABSTRACT

We have compared nine
Enterococcus faecalis
strains with
E. faecalis
V583 by comparative genomic hybridization using microarrays (CGH). The strains used in this study (the “test” strains) originated from various environments. CGH is a powerful and promising tool for obtaining novel information on genome diversity in bacteria. By CGH, one obtains clues about which genes are present or divergent in the strains, compared to a reference strain (here, V583). The information obtained by CGH is important from both ecological and systematic points of view. CGH of
E. faecalis
showed considerable diversity in gene content: Compared to V583, the percentage of divergent genes in the test strains varied from 15% to 23%, and 154 genes were divergent in all strains. The main variation was found in regions corresponding to exogenously acquired or mobile DNA in V583. Antibiotic resistance genes, virulence factors, and integrated plasmid genes dominated among the divergent genes. The strains examined showed various contents of genes corresponding to the pTEF1, pTEF2, and pTEF3 genes in V583. The extensive transport and metabolic capabilities of V583 appeared similar in the test strains; CGH indicated that the ability to transport and metabolize various carbohydrates was similar in the test strains (verified by API 50 CH assays). The contents of genes related to stress tolerance appeared similar in V583 and the nine test strains, supporting the view of
E. faecalis
as an organism able to resist harsh conditions.
Detection of
Vibrio cholerae
by Real-Time Nucleic Acid Sequence-Based Amplification
Authors: Fykse Else M. , Skogan Gunnar , Davies William , Olsen Jaran Strand , Blatny Janet M. 
Published: January 2007

ABSTRACT

A multitarget molecular beacon-based real-time nucleic acid sequence-based amplification (NASBA) assay for the specific detection of
Vibrio cholerae
has been developed. The genes encoding the cholera toxin (
ctxA
), the toxin-coregulated pilus (
tcpA
; colonization factor), the
ctxA
toxin regulator (
toxR
), hemolysin (
hlyA
), and the 60-kDa chaperonin product (
groEL
) were selected as target sequences for detection. The beacons for the five different genetic targets were evaluated by serial dilution of RNA from
V. cholerae
cells. RNase treatment of the nucleic acids eliminated all NASBA, whereas DNase treatment had no effect, showing that RNA and not DNA was amplified. The specificity of the assay was investigated by testing several isolates of
V. cholerae
, other
Vibrio
species, and
Bacillus cereus
,
Salmonella enterica
, and
Escherichia coli
strains. The
toxR
,
groEL
, and
hlyA
beacons identified all
V. cholerae
isolates, whereas the
ctxA
and
tcpA
beacons identified the O1 toxigenic clinical isolates. The NASBA assay detected
V. cholerae
at 50 CFU/ml by using the general marker
groEL
and
tcpA
that specifically indicates toxigenic strains. A correlation between cell viability and NASBA was demonstrated for the
ctxA
,
toxR
, and
hlyA
targets. RNA isolated from different environmental water samples spiked with
V. cholerae
was specifically detected by NASBA. These results indicate that NASBA can be used in the rapid detection of
V. cholerae
from various environmental water samples. This method has a strong potential for detecting toxigenic strains by using the
tcpA
and
ctxA
markers. The entire assay including RNA extraction and NASBA was completed within 3 h.
Characterization of the Prokaryotic Diversity in Cold Saline Perennial Springs of the Canadian High Arctic
Authors: Perreault Nancy N. , Andersen Dale T. , Pollard Wayne H. , Greer Charles W. , Whyte Lyle G. 
Published: January 2007

ABSTRACT

The springs at Gypsum Hill and Colour Peak on Axel Heiberg Island in the
Canadian Arctic originate from deep salt aquifers and are among the few
known examples of cold springs in thick permafrost on Earth. The
springs discharge cold anoxic brines (7.5 to 15.8% salts), with a mean
oxidoreduction potential of −325 mV, and contain high
concentrations of sulfate and sulfide. We surveyed the microbial
diversity in the sediments of seven springs by denaturing gradient gel
electrophoresis (DGGE) and analyzing clone libraries of 16S rRNA genes
amplified with
Bacteria
and
Archaea
-specific primers.
Dendrogram analysis of the DGGE banding patterns divided the springs
into two clusters based on their geographic origin. Bacterial 16S rRNA
clone sequences from the Gypsum Hill library (spring GH-4) were
classified into seven phyla (
Actinobacteria
,
Bacteroidetes
,
Firmicutes
,
Gemmatimonadetes
,
Proteobacteria
,
Spirochaetes
, and
Verrucomicrobia
);
Deltaproteobacteria
and
Gammaproteobacteria
sequences represented half of the clone
library. Sequences related to
Proteobacteria
(82%),
Firmicutes
(9%), and
Bacteroidetes
(6%) constituted
97% of the bacterial clone library from Colour Peak (spring CP-1). Most
GH-4 archaeal clone sequences (79%) were related to the
Crenarchaeota
while half of the CP-1 sequences were related to
orders
Halobacteriales
and
Methanosarcinales
of the
Euryarchaeota
. Sequences related to the sulfur-oxidizing
bacterium
Thiomicrospira psychrophila
dominated both the GH-4
(19%) and CP-1 (45%) bacterial libraries, and 56 to 76% of the
bacterial sequences were from potential sulfur-metabolizing bacteria.
These results suggest that the utilization and cycling of sulfur
compounds may play a major role in the energy production and
maintenance of microbial communities in these unique, cold
environments.
Impact of the Direct Application of Therapeutic Agents to the Terminal Recta of Experimentally Colonized Calves on
Escherichia coli
O157:H7 Shedding
Authors: Naylor Stuart W. , Nart Pablo , Sales Jill , Flockhart Allen , Gally David L. , Low J. Christopher 
Published: January 2007

ABSTRACT

Enterohemorrhagic
Escherichia coli
O157:H7 is an important intestinal pathogen of humans with a main reservoir of domesticated ruminants, particularly cattle. It is anticipated that the risk of human infection can be reduced by controlling the organism within its reservoir hosts. Several options for the control of
E. coli
O157:H7 in cattle have been proposed, but none have been demonstrated to be successful in the field. Here we describe a novel experimental method, based on the terminal-rectum-restricted colonization described previously, to eliminate fecal carriage of
E. coli
O157:H7. In experimentally challenged calves, direct application to the rectal mucosa of either of two therapeutic agents, polymyxin B or chlorhexidine, greatly reduced bacterial shedding levels in the immediate posttreatment period. The most efficacious therapeutic agent, chlorhexidine, was compared in orally and rectally challenged calves. The treatment eliminated high-level shedding and reduced low-level shedding by killing bacteria at the terminal rectum. A rapid-detection system based on the ability to identify
E. coli
O157:H7 from swabs of the rectal mucosa was also assessed. This test was sufficiently sensitive to identify high-level bacterial carriage. Thus, a combination of the detection method and treatment regimens could be used in the field to eliminate high-level fecal excretion of
E. coli
O157:H7, so greatly reducing its prevalence within this host and the risk of human infection.