bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Characterization of an
rsmD
-Like rRNA Methyltransferase from the Wolbachia Endosymbiont of Brugia malayi and Antifilarial Activity of Specific Inhibitors of the Enzyme
Authors: Rana Ajay Kumar , Chandra Sharat , Siddiqi Mohammad Imran , Misra-Bhattacharya Shailja 
Published: June 2013

ABSTRACT

The endosymbiotic organism
Wolbachia
is an attractive antifilarial drug target. Here we report on the cloning and expression of an
rsmD
-like rRNA methyltransferase from the
Wolbachia
endosymbiont of
Brugia malayi
, its molecular properties, and assays for specific inhibitors. The gene was found to be expressed in all the major life stages of
B. malayi
. The purified enzyme expressed in
Escherichia coli
was found to be in monomer form in its native state. The activities of the specific inhibitors (heteroaryl compounds) against the enzyme were tested with
B. malayi
adult and microfilariae for 7 days
in vitro
at various concentrations, and NSC-659390 proved to be the most potent compound (50% inhibitory concentration [IC
50
], 0.32 μM), followed by NSC-658343 (IC
50
, 4.13 μM) and NSC-657589 (IC
50
, 7.5 μM). On intraperitoneal administration at 5 mg/kg of body weight for 7 days to adult jirds into which
B. malayi
had been transplanted intraperitoneally, all the compounds killed a significant proportion of the implanted worms. A very similar result was observed in infected mastomys when inhibitors were administered. Docking studies of enzyme and inhibitors and an
in vitro
tryptophan quenching experiment were also performed to understand the binding mode and affinity. The specific inhibitors of the enzyme showed a higher affinity for the catalytic site of the enzyme than the nonspecific inhibitors and were found to be potent enough to kill the worm (both adults and microfilariae)
in vitro
as well as
in vivo
in a matter of days at micromolar concentrations. The findings suggest that these compounds be evaluated against other pathogens possessing a methyltransferase with a DPPY motif and warrant the design and synthesis of more such inhibitors.
Antibiotic Trapping by Plasmid-Encoded CMY-2 β-Lactamase Combined with Reduced Outer Membrane Permeability as a Mechanism of Carbapenem Resistance in Escherichia coli
Authors: Goessens Wil H. F. , van der Bij Akke K. , van Boxtel Ria , Pitout Johann D. D. , van Ulsen Peter , Melles Damian C. , Tommassen Jan 
Published: June 2013

ABSTRACT

A liver transplant patient was admitted with cholangitis, for which meropenem therapy was started. Initial cultures showed a carbapenem-susceptible (CS)
Escherichia coli
strain, but during admission, a carbapenem-resistant (CR)
E. coli
strain was isolated. Analysis of the outer membrane protein profiles showed that both CS and CR
E. coli
lacked the porins OmpF and OmpC. Furthermore, PCR and sequence analysis revealed that both CS and CR
E. coli
possessed
bla
CTX-M-15
and
bla
OXA-1
. The CR
E. coli
strain additionally harbored
bla
CMY-2
and demonstrated a >15-fold increase in β-lactamase activity against nitrocefin, but no hydrolysis of meropenem was detected. However, nitrocefin hydrolysis appeared strongly inhibited by meropenem. Furthermore, the CMY-2 enzyme demonstrated lower electrophoretic mobility after its incubation either
in vitro
or
in vivo
with meropenem, indicative of its covalent modification with meropenem. The presence of the acyl-enzyme complex was confirmed by mass spectrometry. By transformation of the CMY-2-encoding plasmid into various
E. coli
strains, it was established that both porin deficiency and high-level expression of the enzyme were needed to confer meropenem resistance. In conclusion, carbapenem resistance emerged by a combination of elevated β-lactamase production and lack of porin expression. Due to the reduced outer membrane permeability, only small amounts of meropenem can enter the periplasm, where they are trapped but not degraded by the large amount of the β-lactamase. This study, therefore, provides evidence that the mechanism of “trapping” by CMY-2 β-lactamase plays a role in carbapenem resistance.
Bacterial and Clinical Characteristics of Health Care- and Community-Acquired Bloodstream Infections Due to Pseudomonas aeruginosa
Authors: Hattemer Angela , Hauser Alan , Diaz Maureen , Scheetz Marc , Shah Nirav , Allen Jonathan P. , Porhomayon Jahan , El-Solh Ali A. 
Published: June 2013

ABSTRACT

Health care-associated infections, including
Pseudomonas aeruginosa
bloodstream infection, have been linked to delays in appropriate antibiotic therapy and an increased mortality rate. The objective of this study was to evaluate intrinsic virulence, bacterial resistance, and clinical outcomes of health care-associated bloodstream infections (HCABSIs) in comparison with those of community-acquired bloodstream infections (CABSIs) caused by
P. aeruginosa
. We conducted a retrospective multicenter study of consecutive
P. aeruginosa
bacteremia patients at two university-affiliated hospitals. Demographic, clinical, and treatment data were collected. Microbiologic analyses included
in vitro
susceptibility profiles and type III secretory (TTS) phenotypes. Sixty CABSI and 90 HCABSI episodes were analyzed. Patients with HCABSIs had more organ dysfunction at the time of bacteremia (
P
= 0.05) and were more likely to have been exposed to antimicrobial therapy (
P
< 0.001) than those with CABSIs. Ninety-two percent of the carbapenem-resistant
P. aeruginosa
infections were characterized as HCABSIs. The 30-day mortality rate for CABSIs was 26% versus 36% for HCABSIs (
P
= 0.38). The sequential organ failure assessment score at the time of bacteremia (hazard ratio [HR], 1.2; 95% confidence interval [CI], 1.1 to 1.3) and the TTS phenotype (HR 2.1; 95% CI, 1.1 to 3.9) were found to be independent predictors of the 30-day mortality rate. No mortality rate difference was observed between CABSIs and HCABSIs caused by
P. aeruginosa
. Severity of illness and expression of TTS proteins were the strongest predictors of the 30-day mortality rate due to
P. aeruginosa
bacteremia. Future
P. aeruginosa
bacteremia trials designed to neutralize TTS proteins are warranted.
STRATEGIC ENVIRONMENTAL ASSESSMENTS FOR RENEWABLE ENERGY DEVELOPMENT — COMPARING THE UNITED STATES AND GERMANY
Authors: GEIßLER GESA 
Published: June 2013

Germany and the United States are amongst the leading countries regarding installed renewable energy capacity and are steadily adding new facilities. As balancing the strive for a low carbon energy supply with other environmental interests, such as biodiversity conservation, becomes more prevalent with increasing numbers of wind, solar, biomass, geothermal, and hydro-power facilities, the call for a strategic-level consideration of environmental impacts (SEA) becomes louder. The paper compares the practice of SEAs for renewable energy plans, programmes, and policies in terms of discussion of alternatives, consideration of cumulative effects, and public involvement. A case study analysis compares SEAs from Germany and the United States and evaluates their performance.Results indicate large differences between both countries, with Germany performing less well on average. Therefore, a strong need for improvement becomes obvious. A general conclusion is that both countries need to become more open to strategic assessment of environmental impacts from renewable energy policies, strategies, and legislation (policy SEA), in order to allow for meaningful assessment of alternatives and achieve an environmentally sound low carbon future.
Elastomeric blends of poly(styrene-butadiene-styrene) and conductive heteroaromatic poly(thiourea-azo-ether)
Authors: Kausar Ayesha , Hussain Syed Tajammul 
Published: June 2013

The present work involves the preparation of a new heteroaromatic azo polymer, poly(thiourea-azo-ether; PTAE) using 4,4′-oxydiphenyl bis(thiourea) and diazonium salt solution of 2,6-diaminopyridine. The polymer was easily processable using polar solvents and had high molar mass of 33 × 103 g mol−1. Various concentrations of azo filler and poly(styrene-butadiene-styrene; SBS) blends were then blended in solution phase. The effect of PTAE on processing, conductivity, morphology and thermophysical properties of elastomeric blends was investigated. Field-emission scanning electron microscopic micrographs of SBS/PTAE blends revealed fine dispersal of filler, good adhesion with the matrix and the development of conducting pathways. Accordingly, filler content from 10 to 60 wt% increased the conductivity from 0.77 × 10−1 to 1.43 S cm−1. Ultimate tensile strength of SBS/PTAE (26.94–28.12 MPa) was improved relative to pure SBS. A relationship between PTAE loading and thermal stability of the materials was also observed. The temperature at 10% gravimetric loss was increased from 461 to 499°C, while the glass transition temperature was enhanced from 135 to 147°C. Thermal and conducting data showed better results relative to pure elastomer but lower than the conducting filler. Fine balance of properties renders new materials better than the existing elastomeric blends used in a number of applications.
Performance Outcomes After Repair of Complete Achilles Tendon Ruptures in National Basketball Association Players
Authors: Amin Nirav H. , Old Andrew B. , Tabb Loni P. , Garg Rohit , Toossi Nader , Cerynik Douglas L. 
Published: June 2013

Background: A complete rupture of the Achilles tendon is a devastating injury. Variables affecting return to competition and performance changes for National Basketball Association (NBA) players are not readily evident. Hypothesis: Players in the NBA who ruptured their Achilles tendons and who underwent surgical repair would have more experience in the league, and the performance of those who were able to return to competition would be decreased when compared with their performance before injury and with their control-matched peers. Study Design: Cohort study; Level of evidence, 3. Methods: Data for 18 basketball players with Achilles tendon repair over a 23-year period (1988-2011) were obtained from injury reports, press releases, and player profiles. Variables included age, body mass index (BMI), player position, and number of years playing in the league. Individual season statistics were obtained, and the NBA Player Efficiency Rating (PER) was calculated for 2 seasons before and after injury. Controls were matched by playing position, number of seasons played, and performance statistics. Univariate and multivariate analyses were performed to assess the effect of each factor. Results: At the time of injury, the average age was 29.7 years, average BMI was 25.6, and average playing experience was 7.6 years. Seven players never returned to play an NBA game, whereas 11 players returned to play 1 season, with 8 of those players returning for ≥2 seasons. Players who returned missed an average of 55.9 games. The PER was reduced by 4.57 ( P = .003) in the first season and by 4.38 ( P = .010) in the second season. When compared with controls, players demonstrated a significant decline in the PER the first season ( P = .038) and second season ( P = .081) after their return. Conclusion: The NBA players who returned to play after repair of complete Achilles tendon ruptures showed a significant decrease in playing time and performance. Thirty-nine percent of players never returned to play.
Effects of sample width and inclined angle on flame spread across expanded polystyrene surface in plateau and plain environments
Authors: An Weiguang , Huang Xinjie , Wang Qingsong , Zhang Ying , Sun Jinhua , Liew KM , Wang Hui , Xiao Huahua 
Published: June 2013

To study the effect of sample width and inclined angle on flame spread across expanded polystyrene (EPS) surface, a series of laboratory-scale experiments were conducted in the Lhasa plateau and the Hefei plain. Surface flame height, flame spread rate and preheating zone length were obtained. The dimensionless surface flame height varied as the − n power of the sample width and 0.7 < n < 0.9. As angle of incline increased, the surface flame height first rose and then dropped. The surface flame height difference between maximum and minimum width became smaller with the increase in angle of incline. With an increase in sample width, the flame spread rate first dropped and then rose where the angle of incline was small, while the trend was reverse for samples with larger angle of incline. For EPS at 15°and 30°, the trend of flame spread rate versus sample width in Lhasa was inverse, compared with the results obtained in Hefei. The variation trend of preheating zone length with sample width and inclined angle was different from the flame spread rate trend. However, a linear relationship of vf / w and δph/ w was found in Lhasa plateau. The surface flame height, flame spread rate and preheating zone length in Hefei plain were larger than the results obtained in Lhasa plateau. The experimental results agreed well with theoretical analysis.
Erythrocytosis: the HIF pathway in control
Authors: Franke Kristin , Gassmann Max , Wielockx Ben 
Published: June 2013

AbstractOrganisms living under aerobic conditions need oxygen for the metabolic conversion of nutrition into energy. With the appearance of increasingly complex animals, a specialized transport system (erythrocytes) arose during evolution to provide oxygen to virtually every single cell in the body. Moreover, in case of low environmental partial pressure of oxygen, the number of erythrocytes automatically increases to preserve sustained oxygen delivery. This process relies predominantly on the cytokine erythropoietin (Epo) and its transcription factor hypoxia inducible factor (HIF), whereas the von Hippel-Lindau (VHL) ubiquitin ligase as well as the oxygen-sensitive prolyl hydroxylases (PHDs) represent essential regulators of this oxygen-sensing system. Deregulation of particular members of this pathway (eg, PHD2, HIF2α, VHL) lead to disorders in blood homeostasis as a result of insufficient (anemia) or excessive (erythrocytosis) red blood cell production.
Bacillus anthracis peptidoglycan activates human platelets through FcγRII and complement
Authors: Sun Dawei , Popescu Narcis I. , Raisley Brent , Keshari Ravi S. , Dale George L. , Lupu Florea , Coggeshall K. Mark 
Published: June 2013

Key PointsPGN forms immune complexes with preexisting human anti-PGN antibodies to activate the classical complement pathway. Human platelets are activated by PGN–anti-PGN immune complexes through platelet FcγRIIa and through platelet binding C5b.
A vasculo-protective circuit centered on lipoxin A4 and aspirin-triggered 15-epi-lipoxin A4 operative in murine microcirculation
Authors: Brancaleone Vincenzo , Gobbetti Thomas , Cenac Nicolas , le Faouder Pauline , Colom Bartomeu , Flower Roderick J. , Vergnolle Nathalie , Nourshargh Sussan , Perretti Mauro 
Published: June 2013

Key Points
Fpr2/3 activation controls platelet/neutrophil aggregates to afford LXA4 synthesis, thus inhibiting vascular inflammation on reperfusion. Aspirin can jumpstart this circuit by triggering 15-epi-lipoxin synthesis.
Celecoxib alleviates tamoxifen-instigated angiogenic effects by ROS-dependent VEGF/VEGFR2 autocrine signaling
Authors: Kumar B N Prashanth , Rajput Shashi , Dey Kaushik Kumar , Parekh Aditya , Das Subhasis , Mazumdar Abhijit , Mandal Mahitosh 
Published: June 2013

Abstract

Background
Tamoxifen (TAM) is widely used in the chemotherapy of breast cancer and as a preventive agent against recurrence after surgery. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy. Celecoxib (CXB), a selective COX-2 inhibitor, suppresses VEGF gene expression by targeting the VEGF promoter responsible for its inhibitory effect. For this study, we had selected CXB as non-steroidal anti-inflammatory drug in combination with TAM for suppressing VEGF expression and simultaneously reducing doses of both the drugs.

Methods
The effects of CXB combined with TAM were examined in two human breast cancer cell lines in culture, MCF7 and MDA-MB-231. Assays of proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, and receptor signaling were performed.

Results
Here, we elucidated how the combination of TAM and CXB at nontoxic doses exerts anti-angiogenic effects by specifically targeting VEGF/VEGFR2 autocrine signaling through ROS generation. At the molecular level, TAM-CXB suppresses VHL-mediated HIF-1α activation, responsible for expression of COX-2, MMP-2 and VEGF. Besides low VEGF levels, TAM-CXB also suppresses VEGFR2 expression, confirmed through quantifying secreted VEGF levels, luciferase and RT-PCR studies. Interestingly, we observed that TAM-CXB was effective in blocking VEGFR2 promoter induced expression and further 2 fold decrease in VEGF levels was observed in combination than TAM alone in both cell lines. Secondly, TAM-CXB regulated VEGFR2 inhibits Src expression, responsible for tumor progression and metastasis. FACS and in vivo enzymatic studies showed significant increase in the reactive oxygen species upon TAM-CXB treatment.

Conclusions
Taken together, our experimental results indicate that this additive combination shows promising outcome in anti-metastatic and apoptotic studies. In a line, our preclinical studies evidenced that this additive combination of TAM and CXB is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF and VEGFR2. This ingenious combination might be a better tailored clinical regimen than TAM alone for breast cancer treatment.
Cloning and characterization of bifunctional enzyme farnesyl diphosphate/geranylgeranyl diphosphate synthase from Plasmodium falciparum
Authors: Jordão Fabiana M , Gabriel Heloisa B , Alves João MP , Angeli Claudia B , Bifano Thaís D , Breda Ardala , de Azevedo Mauro F , Basso Luiz A , Wunderlich Gerhard , Kimura Emilia A , Katzin Alejandro M 
Published: June 2013

AbstractBackgroundIsoprenoids are the most diverse and abundant group of natural products. InPlasmodium falciparum, isoprenoid synthesis proceeds through the methyl erythritol diphosphate pathway and the products are further metabolized by farnesyl diphosphate synthase (FPPS), turning this enzyme into a key branch point of the isoprenoid synthesis. Changes in FPPS activity could alter the flux of isoprenoid compounds downstream of FPPS and, hence, play a central role in the regulation of a number of essential functions inPlasmodiumparasites.MethodsThe isolation and cloning of gene PF3D7_18400 was done by amplification from cDNA from mixed stage parasites ofP.falciparum. After sequencing, the fragment was subcloned in pGEX2T for recombinant protein expression. To verify if the PF3D7_1128400 gene encodes a functional rPfFPPS protein, its catalytic activity was assessed using the substrate [4-14C] isopentenyl diphosphate and three different allylic substrates: dimethylallyl diphosphate, geranyl diphosphate or farnesyl diphosphate. The reaction products were identified by thin layer chromatography and reverse phase high-performance liquid chromatography. To confirm the product spectrum formed of rPfFPPS, isoprenic compounds were also identified by mass spectrometry. Apparent kinetic constantsKMandVmaxfor each substrate were determined by Michaelis–Menten; also, inhibition assays were performed using risedronate.ResultsThe expressed protein ofP.falciparumFPPS (rPfFPPS) catalyzes the synthesis of farnesyl diphosphate, as well as geranylgeranyl diphosphate, being therefore a bifunctional FPPS/geranylgeranyl diphosphate synthase (GGPPS) enzyme. The apparentKMvalues for the substrates dimethylallyl diphosphate, geranyl diphosphate and farnesyl diphosphate were, respectively, 68 ± 5 μM, 7.8 ± 1.3 μM and 2.06 ± 0.4 μM. The protein is expressed constitutively in all intra-erythrocytic stages ofP.falciparum, demonstrated by using transgenic parasites with a haemagglutinin-tagged version of FPPS. Also, the present data demonstrate that the recombinant protein is inhibited by risedronate.ConclusionsThe rPfFPPS is a bifunctional FPPS/GGPPS enzyme and the structure of products FOH and GGOH were confirmed mass spectrometry. Plasmodial FPPS represents a potential target for the rational design of chemotherapeutic agents to treat malaria.
Multilocus microsatellite signature and identification of specific molecular markers for Leishmania aethiopica
Authors: Kebede Nigatu , Oghumu Steve , Worku Alemayehu , Hailu Asrat , Varikuti Sanjay , Satoskar Abhay R 
Published: June 2013

Abstract

Background
Leishmaniasis is a clinically and epidemiologically diverse zoonotic disease caused by obligatory, intracellular protozoan parasites of the genus Leishmania. Cutaneous leishmaniasis is the most widely distributed form of the disease characterized by skin lesions. Leishmania aethiopica is considered the predominant etiological agent in Ethiopia. The current study was aimed at developing multilocus microsatellite markers for L. aethiopica isolated from human cutaneous leishmaniasis patients in Ethiopia.

Results

L. aethiopica parasites for the study were obtained from Ethiopia and laboratory analysis was conducted at The Ohio State University. DNA was extracted from cultured parasites and an internal transcribed spacer located at the ribosomal region of L. aethiopica genomic DNA was PCR amplified for species identification. Microsatellite markers were identified using multilocus microsatellite typing. We generated an enriched genomic library, and using Primer3 software, designed PCR primers to amplify sequences flanking the detected microsatellites. Subsequent screening of the amplified markers for length variations was performed by gel electrophoresis.
Using a variety of molecular methods, 22 different microsatellite markers were identified and tested for typing L. aethiopica strains using a number of clinical isolates. Of the 22 markers tested, 5 were polymorphic and showed distinctive multilocus genotypes, classifying them into four clusters. One marker was found to be specific for L. aethiopica, discriminating it from other species of Leishmania.

Conclusion
Multilocus microsatellite typing using the markers developed in this study could be useful for epidemiological and population genetic studies of strains of L. aethiopica in order to investigate the structure and dynamics of the corresponding natural foci. It could also help to answer specific clinical questions, such as the occurrence of local and diffuse lesions, strain correlates of parasite persistence after subclinical infection and lesion comparisons from patients suffering from L. aethiopica infections.