bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear receptor peroxisome proliferator‐activated receptor‐γ is activated in rat microglial cells by the anti‐inflammatory drug HCT1026, a derivative of flurbiprofen
Authors: Bernardo Antonietta , Ajmone‐Cat Maria Antonietta , Gasparini Laura , Ongini Ennio , Minghetti Luisa 
Published: February 2005

AbstractThe peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) is constitutively expressed in primary cultures of rat microglia, the main population of brain resident macrophages, and its ligand‐dependent activation leads to the repression of several microglial functions. A few non‐steroidal anti‐inflammatory drugs (NSAIDs), e.g. indomethacin and ibuprofen, show PPAR‐γ agonistic properties. It has been proposed that PPAR‐γ activation contributes to the potential benefits of the long‐term use of certain NSAIDs in delaying the progression of Alzheimer's disease (AD). Previous data have shown that the NSAID HCT1026 [2‐fluoro‐α‐methyl(1,1′‐biphenyl)4‐acetic acid‐4‐(nitrooxy)butyl ester], a derivative of flurbiprofen which releases nitric oxide (NO), reduces the number of reactive microglial cells in a variety of models. This evidence together with the chemical analogy with ibuprofen led us to investigate whether flurbiprofen and HCT1026 interact with PPAR‐γ and interfere with microglial activation. We found that a low concentration (1 µm) of HCT1026, but not flurbiprofen, activated PPAR‐γ in primary cultures of rat microglia, with kinetics similar to those of the synthetic agonist ciglitazone. The PPAR‐γ antagonist GW9662 (2‐chloro‐5‐nitrobenzanilide) prevented the activation of PPAR‐γ by HCT1026. Interestingly, unlike other NSAIDs that activate PPAR‐γ at concentrations higher than those required for cyclooxygenase inhibition, HCT1026 activated PPAR‐γ and inhibited prostaglandin E2 synthesis at the same low concentration (1 µm). The results suggest that HCT1026 may exert additional anti‐inflammatory actions through PPAR‐γ activation, allowing a more effective control of microglial activation and brain inflammation.
Activation of astrocytes in brain of conscious rats during acoustic stimulation: acetate utilization in working brain
Authors: Cruz Nancy F. , Lasater Amelia , Zielke H. Ronald , Dienel Gerald A. 
Published: February 2005

AbstractTo evaluate the response of astrocytes in the auditory pathway to increased neuronal signaling elicited by acoustic stimulation, conscious rats were presented with a unilateral broadband click stimulus and functional activation was assessed by quantitative autoradiography using three tracers to pulse label different metabolic pools in brain: [2‐14C]acetate labels the ‘small’ (astrocytic) glutamate pool, [1‐14C]hydroxybutyrate labels the ‘large’ glutamate pool, and [14C]deoxyglucose, reflects overall glucose utilization (CMRglc) in all brain cells. CMRglc rose during brain activation, and increased activity of the oxidative pathway in working astrocytes during acoustic stimulation was registered with [2‐14C]acetate. In contrast, the stimulation‐induced increase in metabolic activity was not reflected by greater trapping of products of [1‐14C]hydroxybutyrate. The [2‐14C]acetate uptake coefficient in the inferior colliculus and lateral lemniscus during acoustic stimulation was 15% and 18% (p < 0.01) higher in the activated compared to contralateral hemisphere, whereas CMRglc in these structures rose by 66% (p < 0.01) and 42% (p < 0.05), respectively. Calculated rates of brain utilization of blood‐borne acetate (CMRacetate) are about 15–25% of total CMRglc in non‐stimulated tissue and 10–20% of CMRglc in acoustically activated structures; they range from 28 to 115% of estimated rates of glucose oxidation in astrocytes. The rise in acetate utilization during acoustic stimulation is modest compared to total CMRglc, but astrocytic oxidative metabolism of ‘minor’ substrates present in blood can make a significant contribution to the overall energetics of astrocytes and astrocyte–neuron interactions in working brain.
Biochemical and functional evidence for heteromeric assembly of P2X1 and P2X4 subunits
Authors: Nicke Annette , Kerschensteiner Daniel , Soto Florentina 
Published: February 2005

AbstractP2X receptors are ligand‐gated ion channels activated by extracellular ATP. In expression systems, P2X subunits form homo‐ and heterotrimeric receptors. Heteromerization is also likely to occur in vivo as (i) most P2X subunits show overlapping distribution in different tissues and (ii) the functional properties of many native P2X receptors differ from those of heterologously expressed homomeric receptors. Here, we used the Xenopus laevis oocyte expression system to test for heteromerization of P2X1 and P2X4 subunits. Upon co‐injection, P2X4 subunits were co‐purified with hexahistidyl‐tagged P2X1 subunits indicating heteromerization. Blue native polyacrylamide gel electrophoresis (BN‐PAGE) analysis of these P2X complexes excluded artificial aggregation and confirmed that both subunits were present in trimeric complexes of the same size. Two‐electrode voltage‐clamp experiments revealed functional P2X receptors with kinetic properties resembling homomeric P2X4 receptors and a pharmacological profile similar to homomeric P2X1 receptors. Thus, application of α,β‐methylene ATP evoked a slowly desensitizing current sensitive to the antagonists suramin and 2′,3′‐O‐(2,4,6‐trinitrophenyl)‐ATP. This study provides for the first time biochemical and functional evidence for the formation of heteromeric P2X1+4 receptors. These receptors may account for native P2X mediated responses that until now could not be correlated with previously described recombinant P2X receptors.
Objective measurements of radiotherapy‐induced erythema
Authors: Nyström Josefina , Geladi Paul , Lindholm‐Sethson Britta , Rattfelt Jenny , Svensk Ann‐Christin , Franzen Lars 
Published: February 2005

Background/aims: The development of acute radiation erythema is a common phenomenon among patients undergoing radiotherapy treatment. Because of the absence of reliable objective classification methods, the degree of skin reaction can at present mainly be judged subjectively in the clinic. This has motivated the present preliminary study, concerning the first steps in the development of an objective method for skin reaction classification.Methods: Three non‐invasive techniques were used: near‐infrared (NIR) spectroscopy, laser Doppler perfusion imaging and digital photography. The NIR spectra were analysed with principal component analysis (PCA), and the results from the other two with traditional univariate methods. Measurements were made on breast cancer patients who had been exposed to different irradiation doses. A total of 28 breast cancer patients participated one to three times each; 12 were treated with photons at 4 or 6 MeV and 16 were treated with high‐energy electrons between 10 and 20 MeV to a maximum dose of 50 Gy.Results: PCA of NIR spectra shows that information on radiation dose lies mainly in the first principal component. It is observed that the higher the dose the higher the score value. The results from the laser Doppler measurements show that in 79% of the cases the perfusion increases significantly with radiation dose. Analysis of the digital photography shows that a proposed skin redness index (SRI), increases with a higher radiation dose. However, the increase in most cases is not significant. By combining all data, correlation to radiation doses was seen for 74% of the patients who participated more than once.Conclusion: All three non‐invasive methods correlate with the radiation dose but to various degrees. NIR spectroscopy, laser Doppler and a combination of the three techniques are the most promising methods for characterising erythema.
The High-Affinity Maltose/Trehalose ABC Transporter in the Extremely Thermophilic Bacterium
Thermus thermophilus
HB27 Also Recognizes Sucrose and Palatinose
Authors: Silva Zélia , Sampaio Maria-Manuel , Henne Anke , Böhm Alex , Gutzat Ruben , Boos Winfried , da Costa Milton S. , Santos Helena 
Published: February 2005

ABSTRACT

We have studied the transport of trehalose and maltose in the thernophilic bacterium
Thermus thermophilus
HB27, which grows optimally in the range of 70 to 75°C. The

K
m

values at 70°C were 109 nM for trehalose and 114 nM for maltose; also, a high

K
m

(424 nM) was found for the uptake of sucrose. Competition studies showed that a single transporter recognizes trehalose, maltose, and sucrose, while
d
-galactose,
d
-fucose,
l
-rhamnose,
l
-arabinose, and
d
-mannose were not competitive inhibitors. In the recently published genome of
T. thermophilus
HB27, two gene clusters designated
malEFG
1 (TTC1627 to -1629) and
malEFG
2 (TTC1288 to -1286) and two monocistronic genes designated
malK1
(TTC0211) and
malK2
(TTC0611) are annotated as trehalose/maltose and maltose/maltodextrin transport systems, respectively. To find out whether any of these systems is responsible for the transport of trehalose, the
malE1
and
malE2
genes, lacking the sequence encoding the signal peptides, were expressed in
Escherichia coli
. The binding activity of pure recombinant proteins was analyzed by equilibrium dialysis. MalE1 was able to bind maltose, trehalose, and sucrose but not glucose or maltotetraose (

K
d

values of 103, 67, and 401 nM, respectively). Mutants with disruptions in either
malF1
or
malK1
were unable to grow on maltose, trehalose, sucrose, or palatinose, whereas mutants with disruption in
malK2
or
malF2
showed no growth defect on any of these sugars. Therefore,
malEFG1
encodes the binding protein and the two transmembrane subunits of the trehalose/maltose/sucrose/palatinose ABC transporter, and
malK1
encodes the ATP-binding subunit of this transporter. Despite the presence of an efficient transporter for trehalose, this compound was not used by HB27 for osmoprotection. MalE1 and MalE2 exhibited extremely high thermal stability: melting temperatures of 90°C for MalE1 and 105°C for MalE2 in the presence of 2.3 M guanidinium chloride. The latter protein did not bind any of the sugars examined and is not implicated in a maltose/maltodextrin transport system. This work demonstrates that
malEFG1
and
malK1
constitute the high-affinity ABC transport system of
T. thermophilus
HB27 for trehalose, maltose, sucrose, and palatinose.
A Protein Secretion Pathway Critical for
Mycobacterium tuberculosis
Virulence Is Conserved and Functional in
Mycobacterium smegmatis
Authors: Converse Scott E. , Cox Jeffery S. 
Published: February 2005

ABSTRACT

The Snm protein secretion system is a critical determinant of
Mycobacterium tuberculosis
virulence. However, genes encoding components of this pathway are conserved among all mycobacteria, including the nonpathogenic saprophyte
Mycobacterium smegmatis
. We show that the Snm system is operational in
M. smegmatis
and that secretion of its homologous ESAT-6 and CFP-10 substrates is regulated by growth conditions. Importantly, we show that Snm secretion in
M. smegmatis
requires genes that are homologous to those required for secretion in
M. tuberculosis
. Using a gene knockout strategy in
M. smegmatis
, we have also discovered four new gene products that are essential for Snm secretion, including the serine protease mycosin 1. Despite the evolutionary distance between
M. smegmatis
and
M. tuberculosis
, the
M. smegmatis
Snm system can secrete the
M. tuberculosis
ESAT-6 and CFP-10 proteins, suggesting that substrate recognition is also conserved between the two species.
M. smegmatis
, therefore, represents a powerful system to study the multicomponent Snm secretory machine and to understand the role of this conserved system in mycobacterial biology.
AU-Rich Sequences within 5′ Untranslated Leaders Enhance Translation and Stabilize mRNA in
Escherichia coli
Authors: Komarova Anastassia V. , Tchufistova Ludmila S. , Dreyfus Marc , Boni Irina V. 
Published: February 2005

ABSTRACT

We have shown previously that when the
Escherichia coli
chromosomal
lacZ
gene is put under the control of an extended Shine-Dalgarno (SD) sequence (10 or 6 nucleotides in length), the translation efficiency can be highly variable, depending on the presence of AU-rich targets for ribosomal protein S1 in the mRNA leader. Here, the same strains have been used to examine the question of how strong ribosome binding to extended SD sequences affects the stability of
lacZ
mRNAs translated with different efficiencies. The steady-state concentration of the
lacZ
transcripts has been found to vary over a broad range, directly correlating with translation efficiency but not with the SD duplex stability. The observed strain-to-strain variations in
lacZ
mRNA level became far less marked in the presence of the
rne-1
mutation, which partially inactivates RNase E. Together, the results show that (i) an SD sequence, even one that is very long, cannot stabilize the
lacZ
mRNA in
E. coli
if translation is inefficient; (ii) inefficiently translated
lacZ
transcripts are sensitive to RNase E; and (iii) AU-rich elements inserted upstream of a long SD sequence enhance translation and stabilize mRNA, despite the fact that they constitute potential RNase E sites. These data strongly support the idea that the
lacZ
mRNA in
E. coli
can be stabilized only by translating, and not by stalling, ribosomes.
The Wax Ester Synthase/Acyl Coenzyme A:Diacylglycerol Acyltransferase from
Acinetobacter
sp. Strain ADP1: Characterization of a Novel Type of Acyltransferase
Authors: Stöveken Tim , Kalscheuer Rainer , Malkus Ursula , Reichelt Rudolf , Steinbüchel Alexander 
Published: February 2005

ABSTRACT

The wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT) catalyzes the final steps in triacylglycerol (TAG) and wax ester (WE) biosynthesis in the gram-negative bacterium
Acinetobacter
sp. strain ADP1. It constitutes a novel class of acyltransferases which is fundamentally different from acyltransferases involved in TAG and WE synthesis in eukaryotes. The enzyme was purified by a three-step purification protocol to apparent homogeneity from the soluble fraction of recombinant
Escherichia coli
Rosetta (DE3)pLysS (pET23a::
atfA
). Purified WS/DGAT revealed a remarkably low substrate specificity, accepting a broad range of various substances as alternative acceptor molecules. Besides having DGAT and WS activity, the enzyme possesses acyl-CoA:monoacylglycerol acyltransferase (MGAT) activity. The
sn
-1 and
sn
-3 positions of acylglycerols are accepted with higher specificity than the
sn
-2 position. Linear alcohols ranging from ethanol to triacontanol are efficiently acylated by the enzyme, which exhibits highest specificities towards medium-chain-length alcohols. The acylation of cyclic and aromatic alcohols, such as cyclohexanol or phenylethanol, further underlines the unspecific character of this enzyme. The broad range of possible substrates may lead to biotechnological production of interesting wax ester derivatives. Determination of the native molecular weight revealed organization as a homodimer. The large number of WS/DGAT-homologous genes identified in pathogenic mycobacteria and their possible importance for the pathogenesis and latency of these bacteria makes the purified WS/DGAT from
Acinetobacter
sp. strain ADP1 a valuable model for studying this group of proteins in pathogenic mycobacteria.
Protein Isoaspartate Methyltransferase Is a Multicopy Suppressor of Protein Aggregation in
Escherichia coli
Authors: Kern Renée , Malki Abderrahim , Abdallah Jad , Liebart Jean-Claude , Dubucs Catherine , Yu Myeong Hee , Richarme Gilbert 
Published: February 2005

ABSTRACT

We used preS2-S′-β-galactosidase, a three-domain fusion protein that aggregates extensively at 43°C in the cytoplasm of
Escherichia coli
, to search for multicopy suppressors of protein aggregation and inclusion body formation and took advantage of the known differential solubility of preS2-S′-β-galactosidase at 37 and 43°C to develop a selection procedure for the gene products that would prevent its aggregation in vivo at 43°C. First, we demonstrate that the differential solubility of preS2-S′-β-galactosidase results in a lactose-positive phenotype at 37°C as opposed to a lactose-negative phenotype at 43°C. We searched for multicopy suppressors of preS2-S′-β-galactosidase aggregation by selecting pink lactose-positive colonies on a background of white lactose-negative colonies at 43°C after transformation of bacteria with an
E. coli
gene bank. We discovered that protein isoaspartate methyltransferase (PIMT) is a multicopy suppressor of preS2-S′-β-galactosidase aggregation at 43°C. Overexpression of PIMT reduces the amount of preS2-S′-β-galactosidase found in inclusion bodies at 43°C and increases its amount in soluble fractions. It reduces the level of isoaspartate formation in preS2-S′-β-galactosidase and increases its thermal stability in
E. coli
crude extracts without increasing the thermostability of a control protein, citrate synthase, in the same extracts. We could not detect any induction of the heat shock response resulting from PIMT overexpression, as judged from amounts of DnaK and GroEL, which were similar in the PIMT-overproducing and control strains. These results suggest that PIMT might be overburdened in some physiological conditions and that its overproduction may be beneficial in conditions in which protein aggregation occurs, for example, during biotechnological protein overproduction or in protein aggregation diseases.
The Flag-2 Locus, an Ancestral Gene Cluster, Is Potentially Associated with a Novel Flagellar System from
Escherichia coli
Authors: Ren Chuan-Peng , Beatson Scott A. , Parkhill Julian , Pallen Mark J. 
Published: February 2005

ABSTRACT

Escherichia coli
K-12 possesses two adjacent, divergent, promoterless flagellar genes,
fhiA
-
mbhA
, that are absent from
Salmonella enterica
. Through bioinformatics analysis, we found that these genes are remnants of an ancestral 44-gene cluster and are capable of encoding a novel flagellar system, Flag-2. In enteroaggregative
E. coli
strain 042, there is a frameshift in
lfgC
that is likely to have inactivated the system in this strain. Tiling path PCR studies showed that the Flag-2 cluster is present in 15 of 72 of the well-characterized ECOR strains. The Flag-2 system resembles the lateral flagellar systems of
Aeromonas
and
Vibrio
, particularly in its apparent dependence on RpoN. Unlike the conventional Flag-1 flagellin, the Flag-2 flagellin shows a remarkable lack of sequence polymorphism. The Flag-2 gene cluster encodes a flagellar type III secretion system (including a dedicated flagellar sigma-antisigma combination), thus raising the number of distinct type III secretion systems in
Escherichia
/
Shigella
to five. The presence of the Flag-2 cluster at identical sites in
E. coli
and its close relative
Citrobacter rodentium
, combined with its absence from
S. enterica
, suggests that it was acquired by horizontal gene transfer after the former two species diverged from
Salmonella
. The presence of Flag-2-like gene clusters in
Yersinia pestis
,
Yersinia pseudotuberculosis
, and
Chromobacterium violaceum
suggests that coexistence of two flagellar systems within the same species is more common than previously suspected. The fact that the Flag-2 gene cluster was not discovered in the first 10
Escherichia
/
Shigella
genome sequences studied emphasizes the importance of maintaining an energetic program of genome sequencing for this important taxonomic group.
DNA Binding: a Novel Function of
Pseudomonas aeruginosa
Type IV Pili
Authors: van Schaik Erin J. , Giltner Carmen L. , Audette Gerald F. , Keizer David W. , Bautista Daisy L. , Slupsky Carolyn M. , Sykes Brian D. , Irvin Randall T. 
Published: February 2005

ABSTRACT

The opportunistic pathogen
Pseudomonas aeruginosa
produces multifunctional, polar, filamentous appendages termed type IV pili. Type IV pili are involved in colonization during infection, twitching motility, biofilm formation, bacteriophage infection, and natural transformation. Electrostatic surface analysis of modeled pilus fibers generated from
P. aeruginosa
strain PAK, K122-4, and KB-7 pilin monomers suggested that a solvent-exposed band of positive charge may be a common feature of all type IV pili. Several functions of type IV pili, including natural transformation and biofilm formation, involve DNA. We investigated the ability of
P. aeruginosa
type IV pili to bind DNA. Purified PAK, K122-4, and KB-7 pili were observed to bind both bacterial plasmid and salmon sperm DNA in a concentration-dependent and saturable manner. PAK pili had the highest affinity for DNA, followed by K122-4 and KB-7 pili. DNA binding involved backbone interactions and preferential binding to pyrimidine residues even though there was no evidence of sequence-specific binding. Pilus-mediated DNA binding was a function of the intact pilus and thus required elements present in the quaternary structure. However, binding also involved the pilus tip as tip-specific, but not base-specific, antibodies inhibited DNA binding. The conservation of a Thr residue in all type IV pilin monomers examined to date, along with the electrostatic data, implies that DNA binding is a conserved function of type IV pili. Pilus-mediated DNA binding could be important for biofilm formation both in vivo during an infection and ex vivo on abiotic surfaces.
The Hfq Homolog inLegionella pneumophilaDemonstrates Regulation by LetA and RpoS and Interacts with the Global Regulator CsrA
Authors: McNealy Tamara L , Forsbach-Birk Vera , Shi Chunwei , Marre Reinhard 
Published: February 2005

ABSTRACTA gene inLegionella pneumophilathat has significant homology to publishedhfqgenes demonstrated regulation by RpoS and the transcriptional regulator LetA. Additionally, Hfq has a positive effect on the presence of transcripts of the genes for CsrA and the ferric uptake regulator Fur. Mutants lackinghfqdemonstrate defects in growth and pigmentation and slight defects in virulence in both amoeba and macrophage infection models. Hfq appears to play a major role in exponential-phase regulatory cascades ofL. pneumophila.
Daily antibiotic cost of nosocomial infections in a Turkish university hospital
Authors: Inan Dilara , Saba Rabin , Gunseren Filiz , Ongut Gozde , Turhan Ozge , Yalcin Ata Nevzat , Mamikoglu Latife 
Published: February 2005

Abstract
Background
Many studies associated nosocomial infections with increased hospital costs due to extra days in hospital, staff time, extra investigations and drug treatment. The cost of antibiotic treatment for these infections represents a significant part of hospital expenditure. This prospective observational study was designed to determine the daily antibiotic cost of nosocomial infections per infected adult patient in Akdeniz University Hospital.

Methods
All adult patients admitted to the ICUs between January 1, 2000, and June 30, 2003 who had only one nosocomial infection during their stay were included in the study. Infection sites and pathogens, antimicrobial treatment of patient and it's cost were recorded. Daily antibiotic costs were calculated per infected patient.

Results
Among the 8460 study patients, 817 (16.6%) developed 1407 episodes of nosocomial infection. Two hundred thirty three (2.7%) presented with only one nosocomial infection. Mean daily antibiotic cost was $89.64. Daily antibiotic cost was $99.02 for pneumonia, $94.32 for bloodstream infection, $94.31 for surgical site infection, $52.37 for urinary tract infection, and $162.35 for the other infections per patient. The treatment of Pseudomonas aeruginosa infections was the most expensive infection treated. Piperacillin-tazobactam and amikacin were the most prescribed antibiotics, and meropenem was the most expensive drug for treatment of the nosocomial infections in the ICU.

Conclusions
Daily antibiotic cost of nosocomial infections is an important part of extra costs that should be reduced providing rational antibiotic usage in hospitals.