bluuebunny/crossref_metadata_2025_split huggingface dataset:
Porphyromonas gingivalis
Ferrous Iron Transporter FeoB1 Influences Sensitivity to Oxidative Stress
Authors: Anaya-Bergman Cecilia , He Jia , Jones Kevin , Miyazaki Hiroshi , Yeudall Andrew , Lewis Janina P. 
Published: November 2009

ABSTRACT

Porphyromonas gingivalis
FeoB1 is a ferrous iron transporter. Analysis of parental and
feoB1
-deficient strains of the periodontal pathogen revealed that the
feoB1
-deficient mutant strain had an increased ability to survive oxidative stress. Specifically, survival of the mutant strain was increased 33% with exposure to peroxide and 5% with exposure to atmospheric oxygen compared to the parental strain. Interestingly, the ability to survive intracellularly also increased fivefold in the case of the
feoB1
-deficient mutant. Our data suggest that although the FeoB1 protein is required for ferrous iron acquisition in
P. gingivalis
, it also has an adverse effect on survival of the bacterium under oxidative stress conditions. Finally, we show that
feoB1
expression is not iron dependent and is dramatically reduced in the presence of host cells, consistent with the observed deleterious role it plays in bacterial survival.
Ferredoxin Is Involved in Secretion of Cytotoxic Necrotizing Factor 1 across the Cytoplasmic Membrane in
Escherichia coli
K1
Authors: Yu Hao , Kim Kwang Sik 
Published: November 2009

ABSTRACT

We previously showed that cytotoxic necrotizing factor 1 (CNF1) contributes to
Escherichia coli
K1 invasion of human brain microvascular endothelial cells (HBMEC) and interacts with the receptor on the surface of HBMEC. CNF1 is the cytoplasmic protein, and it remains incompletely understood how CNF1 is secreted across the inner and outer membranes in
E. coli
K1. In order to investigate the genetic determinants for secretion of CNF1 in
E. coli
K1, we performed Tn
5
mutagenesis screening by applying β-lactamase as a reporter to monitor secretion of CNF1. We identified a Tn
5
mutant that exhibited no β-lactamase activity in the culture supernatant and in which the mutated gene encodes a ferredoxin gene (
fdx
). In the
fdx
deletion mutant, there was no evidence of translocation of CNF1 into HBMEC. Western blot analysis of the
fdx
deletion mutant revealed that ferredoxin is involved in translocation of CNF1 across the cytoplasmic membrane. The
fdx
mutant exhibited significantly decreased invasion of HBMEC, similar to the decreased HBMEC invasion observed with the CNF1 mutant. The failures to secrete CNF1 and invade HBMEC of the
fdx
mutant were restored to the levels of the parent strain by complementation with
fdx
. These findings demonstrate for the first time that ferredoxin is involved in secretion of CNF1 across the inner membrane in meningitis-causing
E. coli
K1.
Growth-Inhibitory Antibodies Are Not Necessary for Protective Immunity to Malaria Infection
Authors: Murhandarwati E. Elsa Herdiana , Wang Lina , de Silva Harini D. , Ma Charles , Plebanski Magdalena , Black Casilda G. , Coppel Ross L. 
Published: November 2009

ABSTRACTThe absence of a validated surrogate marker for the immune state has complicated the design of a subunit vaccine against asexual stages ofPlasmodium falciparum. In particular, it is not known whether the capacity to induce antibodies that inhibit parasite growthin vitrois an important criterion for selection ofP. falciparumproteins to be assessed in human vaccine trials. We examined this issue in thePlasmodium yoeliirodent malaria model using the 19-kDa C-terminal fragment of merozoite surface protein 1 (MSP119). To examine the relationship between inhibitory antibodies in immunized mice and the immune state, as indicated by resistance to a blood-stage challenge, we used an allelic replacement strategy to generate a transgenicP. falciparumline that expresses MSP119fromP. yoelii. We show that MSP119is functionally conserved across these two divergentPlasmodiumspecies, and replacing PfMSP119with PyMSP119has no detectable effect on parasite growthin vitro. By comparing growth rates of this transgenic line with a matched transgenic line that expresses the endogenous PfMSP119, we developed an assay to measure the specific growth-inhibitory activity directed exclusively to the PyMSP119protein in the sera from vaccinated animals. To validate this assay, sera from rabbits immunized with recombinant PyMSP119were tested and showed specific inhibitory activity in a concentration-dependent manner. In mice that were immunized with recombinant PyMSP119, the levels of PyMSP119-specific inhibitory activity did not correlate with the total antibody levels measured by enzyme-linked immunosorbent assay. Furthermore, they did not correlate with resistance to subsequent blood-stage infection, and some mice with complete protection showed no detectable inhibitory activity in their prechallenge sera. These data indicated that growth-inhibitory activity measuredin vitrowas not a reliable predictor of immune statusin vivo, and the reliance on this criterion to select vaccine candidates for human clinical trials may be misplaced. The transgenic lines further offer useful tools for comparing the efficacy of MSP119-based vaccines that utilize different immunization regimens and antigen formulations.
In VitroGrowth-Inhibitory Activity and Malaria Risk in a Cohort Study in Mali
Authors: Crompton Peter D. , Miura Kazutoyo , Traore Boubacar , Kayentao Kassoum , Ongoiba Aissata , Weiss Greta , Doumbo Safiatou , Doumtabe Didier , Kone Younoussou , Huang Chiung-Yu , Doumbo Ogobara K. , Miller Louis H. , Long Carole A. , Pierce Susan K. 
Published: November 2009

ABSTRACTImmunity to the asexual blood stage ofPlasmodium falciparumis complex and likely involves several effector mechanisms. Antibodies are thought to play a critical role in malaria immunity, and a correspondingin vitrocorrelate of antibody-mediated immunity has long been sought to facilitate malaria vaccine development. The growth inhibition assay (GIA) measures the capacity of antibodies to limit red blood cell (RBC) invasion and/or growth ofP. falciparum in vitro. In humans, naturally acquired and vaccine-inducedP. falciparum-specific antibodies have growth-inhibitory activity, but it is unclear if growth-inhibitory activity correlates with protection from clinical disease. In a longitudinal study in Mali, purified IgGs, obtained from plasmas collected before the malaria season from 220 individuals aged 2 to 10 and 18 to 25 years, were assayed for growth-inhibitory activity. Malaria episodes were recorded by passive surveillance over the subsequent 6-month malaria season. Logistic regression showed that greater age (odds ratio [OR], 0.78; 95% confidence interval [95% CI], 0.63 to 0.95;P= 0.02) and growth-inhibitory activity (OR, 0.50; 95% CI, 0.30 to 0.85;P= 0.01) were significantly associated with decreased malaria risk in children. A growth-inhibitory activity level of 40% was determined to be the optimal cutoff for discriminating malaria-immune and susceptible individuals in this cohort, with a sensitivity of 97.0%, but a low specificity of 24.3%, which limited the assay's ability to accurately predict protective immunity and to serve as anin vitrocorrelate of antibody-mediated immunity. These data suggest that antibodies which block merozoite invasion of RBC and/or inhibit the intra-RBC growth of the parasite contribute to but are not sufficient for the acquisition of malaria immunity.
Browder's Convergence for Uniformly Asymptotically Regular Nonexpansive Semigroups in Hilbert Spaces
Authors: López Acedo Genaro , Suzuki Tomonari 
Published: November 2009

AbstractWe give a sufficient and necessary condition concerning a Browder's convergence type theorem for uniformly asymptotically regular one-parameter nonexpansive semigroups in Hilbert spaces.
Safety, pharmacokinetics and pharmacodynamics of single doses of rivaroxaban – an oral, direct factor Xa inhibitor – in elderly Chinese subjects
Authors: Jiang Ji , Hu Yufang , Zhang Jianyan , Yang Jueling , Mueck Wolfgang , Kubitza Dagmar , Bauer Richard , Meng Ling , Hu Pei 
Published: November 2009

SummaryRivaroxaban is a novel, oral, direct factor Xa (FXa) inhibitor for the prevention and treatment of thromboembolic disorders. The aim of this study was to investigate the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of rivaroxaban in healthy, elderly Chinese subjects. In this single-centre, single-blind, placebo-controlled, parallel-group, dose-escalation study, 79 subjects, aged 59–74 years (mean 62.8), were randomised to receive once-daily oral doses of rivaroxaban 5, 10, 20, 30 or 40 mg. Rivaroxaban was well tolerated: there was a low incidence of treatment-emergent adverse events and all events were of mild intensity. Rivaroxaban was absorbed rapidly, reaching maximum plasma concentrations within 2–4 hours. The PK of rivaroxaban were dose dependent over the dose range tested. Maximal inhibition of FXa occurred 2–3 hours after dosing and returned to baseline after 24–48 hours, reflecting rivaroxaban plasma concentrations. Inhibition of FXa was associated with dose-dependent effects on global clotting tests. There were no clinically relevant differences in rivaroxaban plasma concentrations between male and female subjects. In conclusion, rivaroxaban was well tolerated and was found to have predictable PK and PD in healthy, elderly Chinese subjects.
A fusion protein with improved thrombolytic effect and low bleeding risk
Authors: Wang Lisheng , Zhang Qinglin , Qin Yide , Wu Chutse , Wang Xiudong , Zhang Guangman , Yu Aiping 
Published: November 2009

SummaryTo resolve the therapeutic dilemma between efficacy of thrombolysis and bleeding risk associated with the use of a combination of thrombolytic and anticoagulant treatments, we created a fusion protein. Staphylokinase was fused to the N-terminus of hirudin using thrombin recognition sequence as linker peptide, resulting in a fusion protein STH.We hypothesised that STH would be cleaved by thrombin at the thrombus site, releasing staphylokinase and hirudin to perform bifunctionally, and attenuating bleeding risk. SDS-PAGE andWestern blot analyses indicated that the linker peptide could be specially recognised and cleaved by thrombin. Amidolytic and thromboelastogram assays showed that the N-terminus of hirudin in STH was blocked by staphylokinase and linker peptide, impeding hirudin’s anticoagulant activity. Once cleaved, STH displayed 35.7% of the anticoagulant activity of equimolar hirudin and exhibited anticoagulant effects in the fibrin clot lysis assay.Thrombin-binding and fibrin clot lysis assays showed that the C-terminus of hirudin retained its high affinity for thrombin. Moreover, STH showed improved thrombolytic effects and a lower bleeding risk in animals. Thus, STH may have the capacity to perform bifunctionally and release anticoagulant activity in a thrombus-targeted manner in vivo, which may reduce the bleeding risk that often accompanies high thrombolytic efficacy in the treatment of thromboembolic diseases.
Different expression of proteins in platelets from aspirin-resistant and aspirin-sensitive patients
Authors: Macaya Carlos , Azcona Luis , Modrego Javier , Mahillo Estela , Bernardo Esther , Fernández-Ortiz Antonio , López-Farré Antonio , Mateos-Cáceres Petra 
Published: November 2009

SummaryThe aim of the present study was to analyse differences in the protein expression profile between platelets from aspirin (ASA)-resistant patients and ASA-sensitive patients. We analysed platelets from 51 clinically stable coronary ischaemic patients taking ASA (100 mg/day) divided into ASA-resistant (n=25) and ASA-sensitive (n=26) based on a platelet functionality test (PFA-100). Proteins associated with cytoskeleton, energetic metabolism, oxidative stress, inflammation and cell survival were analysed by two-dimensional electrophoresis and mass spectrometry. The expression of two gelsolin precursor isotypes and one F-acting capping protein isotype was decreased in ASA-resistant platelets (p<0.05). The expression of glyceraldehyde 3-phosphate dehydrogenase was increased in the ASA-resistant platelets (1751.1 ± 220.6 vs. 4273.3 ± 971.7, 95% confidence interval [CI] 1815.11 to 4061.2, p=0.001). It was accompanied by a reduced expression and activity of 1,6-bisphosphate aldolase in platelets without changes in the content of pyruvate. A reduced expression of gluthathione-S-transferase and the protein disulfide isomerase isotype 1 was found in ASA-resistant platelets. The protein expression of the chloride intracellular channel isotype 1 was increased in ASA-resistant platelets (21.3 ± 3.8 vs. 48.8 ± 6.0, CI 29.5 to 45.95, p=0.03) while the expression of two HSP60 and two HSP71 isotypes was decreased. No changes were observed in proteins associated with inflammation. In conclusion, ASA-resistant and ASA-sensitive platelets are different in terms of the level of expression of proteins associated with mechanisms such as energetic metabolism, cytoskeleton, oxidative stress and cell survival which may be associated with their different ability to respond to ASA.
Genetic manipulation of endothelial cells by viral vectors
Authors: Lindemann Dirk , Schnittler Hans 
Published: November 2009

SummaryThe need for uncovering molecular mechanisms in endothelial cell biology has tremendously increased in the last decades as it became more and more clear that the endothelium is an important target in nearly all diseases and treatments (drug delivery) and plays a central role in regeneration processes. One of the critical methods generally applied in cell biology research to uncover structural and functional aspects is the modulation of protein expression by over-expression, expression of mutant variants or gene silencing. This strategy, however, requires genetic manipulation of the respective cells. The classical gene transfer by chemical transfection techniques works pretty well in a large variety of cultured cells but fails for most endothelial cell types. Insufficient transfection rates and gene expression levels as well as the sensitivity of the endothelium against chemical transfection reagents limits utilisation of this technique for endothelial cell biology research. This holds true not only for primary endothelial cell cultures and endothelial cells in vivo but also for endothelial cell lines, e.g. endothelioma cells. The development of viral vectors originally designed for gene therapy approaches has significantly improved the methodological spectrum in endothelial cell research. Two viral vector systems, based on retroviruses and adenoviruses, deliver transgenic information highly efficient into both cultured endothelial cells and in endothelial cells in vivo, respectively. This review aims to give a comprehensive overview of these two vector systems that appear to be reliable and efficient tools for gene delivery into endothelial cell types.
Intercomparison of Variational Data Assimilation and the Ensemble Kalman Filter for Global Deterministic NWP. Part II: One-Month Experiments with Real Observations
Authors: Buehner Mark , Houtekamer P. L. , Charette Cecilien , Mitchell Herschel L. , He Bin 
Published: November 2009

Abstract
An intercomparison of the Environment Canada variational and ensemble Kalman filter (EnKF) data assimilation systems is presented in the context of producing global deterministic numerical weather forecasts. Five different variational data assimilation approaches are considered including four-dimensional variational data assimilation (4D-Var) and three-dimensional variational data assimilation (3D-Var) with first guess at the appropriate time (3D-FGAT). Also included among these is a new approach, called Ensemble-4D-Var (En-4D-Var), that uses 4D ensemble background-error covariances from the EnKF. A description of the experimental configurations and results from single-observation experiments are presented in the first part of this two-part paper. The present paper focuses on results from medium-range deterministic forecasts initialized with analyses from the EnKF and the five variational data assimilation approaches for the period of February 2007. All experiments assimilate exactly the same full set of meteorological observations and use the same configuration of the forecast model to produce global deterministic medium-range forecasts.
The quality of forecasts in the short (medium) range obtained by using the EnKF ensemble mean analysis is slightly degraded (improved) in the extratropics relative to using the 4D-Var analysis with background-error covariances similar to those used operationally. The use of the EnKF flow-dependent error covariances in the variational system (4D-Var or 3D-FGAT) leads to large (modest) forecast improvements in the southern extratropics (tropics) as compared with using covariances similar to the operational system (a gain of up to 9 h at day 5). The En-4D-Var approach leads to (i) either improved or similar forecast quality when compared with the 4D-Var experiment similar to the currently operational system, (ii) slightly worse forecast quality when compared with the 4D-Var experiment with EnKF error covariances, and (iii) generally similar forecast quality when compared with the EnKF experiment.
Distinct population of highly malignant cells in a head and neck squamous cell carcinoma cell line established by xenograft model
Authors: Chen Chi-Yuan , Chiou Shih-Hwa , Huang Chih-Yang , Jan Chia-Ing , Lin Shu-Chun , Tsai Ming-Long , Lo Jeng-Fan 
Published: November 2009

Abstract
The progression and metastasis of solid tumors, including head and neck squamous cell carcinoma (HNSCC), have been related to the behavior of a small subpopulation of cancer stem cells. Here, we have established a highly malignant HNSCC cell line, SASVO3, from primary tumors using three sequential rounds of xenotransplantation. SASVO3 possesses enhanced tumorigenic ability both in vitro and in vivo. Moreover, SASVO3 exhibits properties of cancer stem cells, including that increased the abilities of sphere-forming, the number of side population cells, the potential of transplanted tumor growth and elevated expression of the stem cell marker Bmi1. Injection of SASVO3 into the tail vein of nude mice resulted in lung metastases. These results are consistent with the postulate that the malignant and/or metastasis potential of HNSCC cells may reside in a stem-like subpopulation.
Disparate oxidant gene expression of airway epithelium compared to alveolar macrophages in smokers
Authors: Carolan Brendan J , Harvey Ben-Gary , Hackett Neil R , O'Connor Timothy P , Cassano Patricia A , Crystal Ronald G 
Published: November 2009

Abstract

Background
The small airway epithelium and alveolar macrophages are exposed to oxidants in cigarette smoke leading to epithelial dysfunction and macrophage activation. In this context, we asked: what is the transcriptome of oxidant-related genes in small airway epithelium and alveolar macrophages, and does their response differ substantially to inhaled cigarette smoke?

Methods
Using microarray analysis, with TaqMan RT-PCR confirmation, we assessed oxidant-related gene expression in small airway epithelium and alveolar macrophages from the same healthy nonsmoker and smoker individuals.

Results
Of 155 genes surveyed, 87 (56%) were expressed in both cell populations in nonsmokers, with higher expression in alveolar macrophages (43%) compared to airway epithelium (24%). In smokers, there were 15 genes (10%) up-regulated and 7 genes (5%) down-regulated in airway epithelium, but only 3 (2%) up-regulated and 2 (1%) down-regulated in alveolar macrophages. Pathway analysis of airway epithelium showed oxidant pathways dominated, but in alveolar macrophages immune pathways dominated.

Conclusion
Thus, the response of different cell-types with an identical genome exposed to the same stress of smoking is different; responses of alveolar macrophages are more subdued than those of airway epithelium. These findings are consistent with the observation that, while the small airway epithelium is vulnerable, alveolar macrophages are not "diseased" in response to smoking.

Trial Registration
ClinicalTrials.gov ID: NCT00224185 and NCT00224198
Reverse genetics through random mutagenesis in Histoplasma capsulatum
Authors: Youseff Brian H , Dougherty Julie A , Rappleye Chad A 
Published: November 2009

Abstract

Background
The dimorphic fungal pathogen Histoplasma capsulatum causes respiratory and systemic disease in humans and other mammals. Progress in understanding the mechanisms underlying the biology and the pathogenesis of Histoplasma has been hindered by a shortage of methodologies for mutating a gene of interest.

Results
We describe a reverse genetics process that combines the random mutagenesis of Agrobacterium-mediated transformation with screening techniques to identify targeted gene disruptions in a collection of insertion mutants. Isolation of the desired mutant is accomplished by arraying individual clones from a pool and employing a PCR-addressing method. Application of this procedure facilitated the isolation of a cbp1 mutant in a North American type 2 strain, a Histoplasma strain recalcitrant to gene knock-outs through homologous recombination. Optimization of cryopreservation conditions allows pools of mutants to be banked for later analysis and recovery of targeted mutants.

Conclusion
This methodology improves our ability to isolate mutants in targeted genes, thereby facilitating the molecular genetic analysis of Histoplasma biology. The procedures described are widely applicable to many fungal systems and will be of particular interest to those for which homologous recombination techniques are inefficient or do not currently exist.
Comparative analysis of the complete sequence of the plastid genome of Parthenium argentatum and identification of DNA barcodes to differentiate Parthenium species and lines
Authors: Kumar Shashi , Hahn Frederick M , McMahan Colleen M , Cornish Katrina , Whalen Maureen C 
Published: November 2009

Abstract

Background

Parthenium argentatum (guayule) is an industrial crop that produces latex, which was recently commercialized as a source of latex rubber safe for people with Type I latex allergy. The complete plastid genome of P. argentatum was sequenced. The sequence provides important information useful for genetic engineering strategies. Comparison to the sequences of plastid genomes from three other members of the Asteraceae, Lactuca sativa, Guitozia abyssinica and Helianthus annuus revealed details of the evolution of the four genomes. Chloroplast-specific DNA barcodes were developed for identification of Parthenium species and lines.

Results
The complete plastid genome of P. argentatum is 152,803 bp. Based on the overall comparison of individual protein coding genes with those in L. sativa, G. abyssinica and H. annuus, we demonstrate that the P. argentatum chloroplast genome sequence is most closely related to that of H. annuus. Similar to chloroplast genomes in G. abyssinica, L. sativa and H. annuus, the plastid genome of P. argentatum has a large 23 kb inversion with a smaller 3.4 kb inversion, within the large inversion. Using the matK and psbA-trnH spacer chloroplast DNA barcodes, three of the four Parthenium species tested, P. tomentosum, P. hysterophorus and P. schottii, can be differentiated from P. argentatum. In addition, we identified lines within P. argentatum.

Conclusion
The genome sequence of the P. argentatum chloroplast will enrich the sequence resources of plastid genomes in commercial crops. The availability of the complete plastid genome sequence may facilitate transformation efficiency by using the precise sequence of endogenous flanking sequences and regulatory elements in chloroplast transformation vectors. The DNA barcoding study forms the foundation for genetic identification of commercially significant lines of P. argentatum that are important for producing latex.