bluuebunny/crossref_metadata_2025_split huggingface dataset:
AinS Quorum Sensing Regulates theVibrio fischeriAcetate Switch
Authors: Studer Sarah V. , Mandel Mark J. , Ruby Edward G. 
Published: May 2008

ABSTRACTThe marine bacteriumVibrio fischeriuses two acyl-homoserine lactone (acyl-HSL) quorum-sensing systems. The earlier signal, octanoyl-HSL, produced by AinS, is required for normal colonization of the squidEuprymna scolopesand, in culture, is necessary for a normal growth yield. In examining the latter requirement, we found that during growth in a glycerol/tryptone-based medium, wild-typeV. fischericells initially excrete acetate but, in a metabolic shift termed the acetate switch, they subsequently utilize the acetate, removing it from the medium. In contrast, anainSmutant strain grown in this medium does not remove the excreted acetate, which accumulates to lethal levels. The acetate switch is characterized by the induction ofacs, the gene encoding acetyl coenzyme A (acetyl-CoA) synthetase, leading to uptake of the excreted acetate. Wild-type cells induce anacstranscriptional reporter 25-fold, coincident with the disappearance of the extracellular acetate; in contrast, theainSmutant did not display significant induction of theacsreporter. Supplementation of the medium of anainSmutant with octanoyl-HSL restored normal levels ofacsinduction and acetate uptake. Additional mutant analyses indicated thatacsregulation was accomplished through the regulator LitR but was independent of the LuxIR quorum-signaling pathway. Importantly, theacsmutant ofV. fischerihas a competitive defect when colonizing the squid, indicating the importance of proper control of acetate metabolism in the light of organ symbiosis. This is the first report of quorum-sensing control of the acetate switch, and it indicates a metabolic connection between acetate utilization and cell density.
mgtAExpression Is Induced by Rob Overexpression and Mediates aSalmonella entericaResistance Phenotype
Authors: Barchiesi Julieta , Castelli María E. , Soncini Fernando C. , Véscovi Eleonora García 
Published: May 2008

ABSTRACTRob is a member of the Sox/Mar subfamily of AraC/XylS-type transcriptional regulators implicated in bacterial multidrug, heavy metal, superoxide, and organic solvent resistance phenotypes. We demonstrate that, inSalmonella enterica, Rob overexpression upregulates the transcription ofmgtA, which codes for the MgtA Mg2+transporter.mgtAwas previously characterized as a member of the Mg2+-modulated PhoPQ regulon. Here we demonstrate that Rob (but not its paralog protein SoxS or MarA) is able to inducemgtAtranscription in a PhoP-independent fashion by binding to a conserved Mar/Sox/Rob motif localized downstream of the PhoP-box and overlapping the PhoP-dependent transcriptional start site. We found that Rob-inducedmgtAexpression confers low-level cyclohexane resistance onSalmonella. BecausemgtAintactness is required for Rob-induced cyclohexane resistance, provided the AcrAB multidrug efflux pump can be expressed, we postulate that MgtA is involved in the AcrAB-mediated cyclohexane detoxification mechanism promoted by Rob inSalmonella.
Role of the Global Transcriptional Regulator PrrA inRhodobacter sphaeroides2.4.1: Combined Transcriptome and Proteome Analysis
Authors: Eraso Jesus M. , Roh Jung Hyeob , Zeng Xiaohua , Callister Stephen J. , Lipton Mary S. , Kaplan Samuel 
Published: May 2008

ABSTRACTThe PrrBA two-component regulatory system is a major global regulator inRhodobacter sphaeroides2.4.1. Here we have compared the transcriptome and proteome profiles of the wild-type (WT) and mutant PrrA2 cells grown anaerobically in the dark with dimethyl sulfoxide as an electron acceptor. Approximately 25% of the genes present in the PrrA2 genome are regulated by PrrA at the transcriptional level, either directly or indirectly, by twofold or more relative to the WT. The genes affected are widespread throughout all COG (cluster of orthologous group) functional categories, with previously unsuspected “metabolic” genes affected in PrrA2 cells. PrrA was found to act as both an activator and a repressor of transcription, with more genes being repressed in the presence of PrrA (9:5 ratio). An analysis of the genes encoding the 1,536 peptides detected through our chromatographic study, which corresponds to 36% coverage of the genome, revealed that approximately 20% of the genes encoding these proteins were positively regulated, whereas approximately 32% were negatively regulated by PrrA, which is in excellent agreement with the percentages obtained for the whole-genome transcriptome profile. In addition, comparison of the transcriptome and proteome mean parameter values for WT and PrrA2 cells showed good qualitative agreement, indicating that transcript regulation paralleled the corresponding protein abundance, although not one for one. The microarray analysis was validated by direct mRNA measurement of randomly selected genes that were both positively and negatively regulated.lacZtranscriptional andkantranslational fusions enabled us to map putative PrrA binding sites and revealed potential gene targets for indirect regulation by PrrA.
Impact of Aeration and Heme-Activated Respiration on
Lactococcus lactis
Gene Expression: Identification of a Heme-Responsive Operon
Authors: Pedersen Martin Bastian , Garrigues Christel , Tuphile Karine , Brun Célia , Vido Karin , Bennedsen Mads , Møllgaard Henrik , Gaudu Philippe , Gruss Alexandra 
Published: May 2008

ABSTRACT

Lactococcus lactis
is a widely used food bacterium mainly characterized for its fermentation metabolism. However, this species undergoes a metabolic shift to respiration when heme is added to an aerobic medium. Respiration results in markedly improved biomass and survival compared to fermentation. Whole-genome microarrays were used to assess changes in
L. lactis
expression under aerobic and respiratory conditions compared to static growth, i.e., nonaerated. We observed the following. (i) Stress response genes were affected mainly by aerobic fermentation. This result underscores the differences between aerobic fermentation and respiration environments and confirms that respiration growth alleviates oxidative stress. (ii) Functions essential for respiratory metabolism, e.g., genes encoding cytochrome
bd
oxidase, menaquinone biosynthesis, and heme uptake, are similarly expressed under the three conditions. This indicates that cells are prepared for respiration once O
2
and heme become available. (iii) Expression of only 11 genes distinguishes respiration from both aerobic and static fermentation cultures. Among them, the genes comprising the putative
ygfCBA
operon are strongly induced by heme regardless of respiration, thus identifying the first heme-responsive operon in lactococci. We give experimental evidence that the
ygfCBA
genes are involved in heme homeostasis.
Impact of Individual Mutations on Increased Fitness in Adaptively Evolved Strains of
Escherichia coli
Authors: Applebee M. Kenyon , Herrgård Markus J. , Palsson Bernhard Ø. 
Published: May 2008

ABSTRACT

We measured the relative fitness among a set of experimentally evolved
Escherichia coli
strains differing by a small number of adaptive mutations by directly measuring allelic frequencies in head-to-head competitions using a mass spectrometry-based method. We compared the relative effects of mutations to the same or similar genes acquired in multiple strains when expressed in allele replacement strains. We found that the strongest determinant of fitness among the evolved strains was the impact of beneficial mutations to the RNA polymerase β and β′ subunit genes. We also identified several examples of epistatic interactions between
rpoB/C
and
glpK
mutations and identified two other mutations that are beneficial only in the presence of previously acquired mutations but that have little or no adaptive benefit to the wild-type strain. Allele frequency estimation is shown to be a highly sensitive method for measuring selection rates during competitions between strains differing by as little as a single-nucleotide polymorphism and may be of great use for investigating epistatic interactions.
Incidence and risk factors of running-related injuries during preparation for a 4-mile recreational running event
Authors: Buist I , Bredeweg S W , Bessem B , van Mechelen W , Lemmink K A P M , Diercks R L 
Published: May 2008

ObjectiveIn this study, the incidence and the sex-specific predictors of running-related injury (RRI) among a group of recreational runners training for a 4-mile running event were determined and identified, respectively.DesignProspective cohort study.MethodsSeveral potential risk factors were prospectively measured in 629 novice and recreational runners. They were observed during an 8-week training period for any running-related musculoskeletal injuries of the lower limbs and back. A running-related injury was defined as any musculoskeletal pain of the lower limb or back causing a restriction of running for at least 1 day.ResultsAt least one RRI was reported by 25.9% of the runners during the 8-week observation period. The incidence of RRI was 30.1 (95% CI 25.4 to 34.7) per 1000 h of running exposure. Multivariate Cox regression showed that male participants were more prone to sustain a RRI than female participants (HR 1.4; 95% CI 1.0 to 2.0). No previous running experience was the most important risk factor in male (HR 2.6; 95% CI 1.2 to 5.5) and female (HR 2.1; 95% CI 1.2 to 3.7) participants.ConclusionsThe incidence of running-related injuries in recreational runners preparing for a 4-mile running event is substantially high. Male and female participants have different risk profiles. Furthermore, the findings suggest that novice runners may benefit the most out of preventive interventions for RRI.
Preparation and Photoluminescent Properties of new Europium Complexes with 2'-Hydroxy- 3-(p- methoxyphenyl) Propiophenone
Authors: Kumar Rajesh , Makrandi J. K. , Taxak Vinod B. , Khatkar Satyender P. 
Published: May 2008

The study of the coordination compounds of the trivalent rare earth ions continues to be an active research area, which may attributed to the luminescent properties of these compounds and their application as optical signal amplifier, electroluminescent devices and luminescent probes in biological system.	The new complex Eu(HMPP)3.2H20 (where HMPP=2'-Hydroxy-3-(p-methoxyphenyl)propiophenone was	synthesized and characterized by I.R.spectroscopy, TGA/DTA and elemental analysis. The qualitative analysis of the complex to detect the presence of europium has been performed by energy dispersive analysis (EDAX). The synthesized complex on exposure to U.V. light at 354nm emits red luminescence with	main peak at 618nm. The complex emitting bright red colour might be promisingly applicable for optical devices, solid state lamps for general illumination purposes, optical signal amplifier, electroluminescent devices and luminescent probes in biological system. Keywords: - Photoluminescence, europium complex, I.R,	elemental analysis, EDAX.
The Use of Electrolyte Additives to Improve the High Temperature Resilience of Li-Ion Cells
Authors: Smart M. C. , Lucht Brett L. , Ratnakumar B. V. 
Published: May 2008

As part of our continuing efforts to develop advanced electrolytes to improve the performance of lithium-ion cells, especially over wide temperature ranges, we have investigated a number of electrolyte additives, which were incorporated into multi-component electrolyte formulations with the intent of improveing the high temperature resilience.	In the present work, we have investigated two Lewis base electrolyte additives developed at URI (1), namely dimethyl acetamide (DMAC) and N-methyl pyrrolidinone (NMP), which have been compared with other previously reported additives (i.e., vinylene carbonate, VC, and vinyl ethylene carbonate, VEC). These Lewis base stabilizing agents have been found to reversibly bind with PF5, preventing LiPF6 and carbonate solvents from undergoing decomposition at high temperature. These additives have been incorporated into a previously developed electrolyte consisting of LiPF6 dissolved in a ternary mixture of carbonates (2). It was determined that cells containing the electrolytes with the additives far outperformed the baseline solution with respect to the extent of capacity retention observed when subjected to high temperatures, with DMAc and VC yielding the best results
The Effect of Low-Intensity Pulsed Ultrasound on Autologous Osteochondral Plugs in a Canine Model
Authors: Cook Stephen D. , Salkeld Samantha L. , Patron Laura P. , Doughty Elizabeth S. , Jones Deryk G. 
Published: May 2008

Background Low-intensity pulsed ultrasound promotes the enchondral portion of fracture healing, which has a direct stimulatory effect on cartilage formation and maturation. Hypothesis Daily ultrasound treatment positively affects the repair and incorporation of modified autologous osteochondral plugs in a canine model. Study Design Controlled laboratory study. Methods In 18 dogs, 2 autologous plugs separated from host cartilage by a 1.5-mm gap were created on the medial femoral condyle in both knees of each dog. One knee was treated daily with a clinically available ultrasound bone stimulator. Animals were sacrificed after 6 and 12 weeks of therapy and the articular surfaces evaluated grossly and histologically. Results Ultrasound-treated sites had significantly improved gross appearance at 6 weeks and histologic appearance at 6 and 12 weeks. The interface repair tissue of ultrasound-treated sites had a more normal translucent appearance than control sites. Ultrasound treatment improved the cell morphologic characteristics of the interface repair tissue and increased subchondral bone regeneration. Bonding of the interface repair tissue between plug and adjacent cartilage was significantly improved compared with control sites. Conclusion Low-intensity pulsed ultrasound improved interface cartilage repair of autologous osteochondral plugs compared with controls in a canine model. Clinical Relevance Improvements in the quality and rate of repair of autologous osteochondral plugs may reduce postoperative recovery time and improve functional outcome.
Primary cystic lung light chain deposition disease: a clinicopathologic entity derived from unmutated B cells with a stereotyped IGHV4-34/IGKV1 receptor
Authors: Colombat Magali , Mal Hervé , Copie-Bergman Christiane , Diebold Jacques , Damotte Diane , Callard Patrice , Fournier Michel , Farcet Jean-Pierre , Stern Marc , Delfau-Larue Marie-Hélène 
Published: May 2008

AbstractWe have recently described a new form of light chain deposition disease (LCDD) presenting as a severe cystic lung disorder requiring lung transplantation. There was no bone marrow plasma cell proliferation. Because of the absence of disease recurrence after bilateral lung transplantation and of serum-free light chain ratio normalization after the procedure, we hypothesized that monoclonal light chain synthesis occurred within the lung. The aim of this study was to look for the monoclonal B-cell component in 3 patients with cystic lung LCDD. Histologic examination of the explanted lungs showed diffuse nonamyloid κ light chain deposits associated with a mild lymphoid infiltrate composed of aggregates of small CD20+, CD5−, CD10− B lymphocytes reminiscent of bronchus-associated lymphoid tissue. Using polymerase chain reaction (PCR), we identified a dominant B-cell clone in the lung in the 3 studied patients. The clonal expansion of each patient shared an unmutated antigen receptor variable region sequence characterized by the use of IGHV4-34 and IGKV1 subgroups with heavy and light chain CDR3 sequences of more than 80% amino acid identity, a feature evocative of an antigen-driven process. Combined with clinical and biologic data, our results strongly argue for a new antigen-driven primary pulmonary lymphoproliferative disorder.
Identification of a novel type of ITD mutations located in nonjuxtamembrane domains of the FLT3 tyrosine kinase receptor
Authors: Breitenbuecher Frank , Schnittger Susanne , Grundler Rebekka , Markova Boyka , Carius Birgit , Brecht Alexandra , Duyster Justus , Haferlach Torsten , Huber Christoph , Fischer Thomas 
Published: May 2008

Abstract
In acute myeloid leukemia (AML), internal tandem duplications (ITDs) of the juxtamembrane (JM) of FLT3 have been shown to play a crucial role in driving proliferation and survival of the leukemic clone. Here, we report the identification of FLT3_ITD mutations located in non-JM domains of the FLT3-receptor. This novel type of FLT3_ITD mutation was found in 216 of 753 (28.7%) of unselected FLT3_ITD-positive AML cases. An FLT3 receptor harbouring a prototypic non-JM ITD (FLT3_ITD627E) mediated constitutive phosphorylation of FLT3 and of STAT5, suggesting that non-JM ITDs confer constitutive activation of the receptor. FLT3_ITD627E induced transformation of hematopoietic 32D cells and led to a lethal myeloproliferative disease in a syngeneic mouse model. Our results indicate that a significant proportion of activating FLT3_ITD mutations is not confined to the JM domain of FLT3. Further studies are warranted to define the biologic and clinical characteristics of non-JM ITDs.
BCR ligation induced by IgM stimulation results in gene expression and functional changes only in IgVH unmutated chronic lymphocytic leukemia (CLL) cells
Authors: Guarini Anna , Chiaretti Sabina , Tavolaro Simona , Maggio Roberta , Peragine Nadia , Citarella Franca , Ricciardi Maria Rosaria , Santangelo Simona , Marinelli Marilisa , De Propris Maria Stefania , Messina Monica , Mauro Francesca Romana , Del Giudice Ilaria , Foà Robert 
Published: May 2008

AbstractChronic lymphocytic leukemia (CLL) patients exhibit a variable clinical course. To investigate the association between clinicobiologic features and responsiveness of CLL cells to anti-IgM stimulation, we evaluated gene expression changes and modifications in cell-cycle distribution, proliferation, and apoptosis of IgVH mutated (M) and unmutated (UM) samples upon BCR cross-linking. Unsupervised analysis highlighted a different response profile to BCR stimulation between UM and M samples. Supervised analysis identified several genes modulated exclusively in the UM cases upon BCR cross-linking. Functional gene groups, including signal transduction, transcription, cell-cycle regulation, and cytoskeleton organization, were up-regulated upon stimulation in UM cases. Cell-cycle and proliferation analyses confirmed that IgM cross-linking induced a significant progression into the G1 phase and a moderate increase of proliferative activity exclusively in UM patients. Moreover, we observed only a small reduction in the percentage of subG0/1 cells, without changes in apoptosis, in UM cases; contrariwise, a significant increase of apoptotic levels was observed in stimulated cells from M cases. These results document that a differential genotypic and functional response to BCR ligation between IgVH M and UM cases is operational in CLL, indicating that response to antigenic stimulation plays a pivotal role in disease progression.
Angiopoietin-2 predicts disease-free survival after allogeneic stem cell transplantation in patients with high-risk myeloid malignancies
Authors: Kümpers Philipp , Koenecke Christian , Hecker Hartmut , Hellpap Julian , Horn Rüdiger , Verhagen Willem , Buchholz Stefanie , Hertenstein Bernd , Krauter Jürgen , Eder Matthias , David Sascha , Göhring Gudrun , Haller Hermann , Ganser Arnold 
Published: May 2008

AbstractEmerging data suggest a critical role for bone marrow angiogenesis in hematologic malignancies. The angiopoietin/Tie ligand-receptor system is an essential regulator of this process. We evaluated whether circulating angiopoietin-2 (Ang-2) is a predictor for the probability of disease-free survival (DFS) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) for high-risk acute myeloid leukemia or myelodysplastic syndrome. Ang-2 was measured by enzyme-linked immunosorbent assay in serum from 20 healthy controls and 90 patients with acute myeloid leukemia or myelodysplastic syndrome before conditioning for HSCT. Circulating Ang-2 was elevated in patients (median, 2.21 ng/mL; range, 0.18-48.84 ng/mL) compared with controls (median, 0.87 ng/mL; range, 0.27-4.51 ng/mL; P < .001). Multivariate analyses confirmed the independent prognostic impact of Ang-2 (hazard ratio [HR] = 2.46; 95% confidence interval [CI], 1.27-4.76, P = .005), percentage of bone marrow infiltration (HR = 1.14; 95% CI, 1.01-1.29, P = .033), and chemotherapy cycles before HSCT (HR = 1.38; 95% CI, 1.01-1.08, P = .048). Regression tree analysis detected optimal cutoff values for Ang-2 and recursively identified bone marrow blasts and Ang-2 as the best predictors for DFS. Because few predictors for DFS exist in the setting of allo-HSCT, Ang-2 may be used as a readily available powerful biomarker to pre-estimate DFS and may open new perspectives for risk-adapted treatment of high-risk myeloid malignancies.
YRRL motifs in the cytoplasmic domain of the thrombopoietin receptor regulate receptor internalization and degradation
Authors: Hitchcock Ian S. , Chen Maximus M. , King Jennifer R. , Kaushansky Kenneth 
Published: May 2008

AbstractThrombopoietin (Tpo), acting through the c-Mpl receptor, promotes the survival and proliferation of hematopoietic stem and progenitor cells and drives megakaryocyte differentiation. The proproliferation and survival signals activated by Tpo must therefore be tightly regulated to prevent uncontrolled cell growth. In this work, we determined the mechanisms that control Tpo-stimulated c-Mpl internalization and defined the processes leading to its degradation. Stimulation of BaF-Mpl cells with Tpo leads to rapid, clathrin-dependent endocytosis of the receptor. Using small interfering RNA (siRNA), we found that inhibition of adaptor protein 2 (AP2), which mediates endocytosis of transmembrane proteins, strongly attenuates Tpo-stimulated c-Mpl internalization. AP2 interacts with YXXΦ motifs and we identified 2 such motifs in c-Mpl (Y8RRL and Y78RRL) and investigated Tpo-stimulated internalization of receptors bearing point mutations at these sites. After Tpo stimulation, internalization was greatly reduced in c-Mpl Y78F and c-Mpl Y8+78F, and these cell lines also exhibited increased proliferation and increased strength and duration of Jak2, STAT5, AKT, and ERK1/2 activation in response to Tpo. We also found that the Y8RRL motif regulates Tpo-stimulated lysosomal degradation of c-Mpl. Our data establishes that c-Mpl cytoplasmic YRRL motifs are responsible for both Tpo-mediated internalization via interactions with AP2 and lysosomal targeting after endocytosis.