bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequence of the 165-Kilobase Catabolic Plasmid pAO1 fromArthrobacter nicotinovoransand Identification of a pAO1-Dependent Nicotine Uptake System
Authors: Igloi Gabor L. , Brandsch Roderich 
Published: March 2003

ABSTRACTThe 165-kb catabolic plasmid pAO1 enables the gram-positive soil bacteriumArthrobacter nicotinovoransto grow on the tobacco alkaloidl-nicotine. The 165,137-nucleotide sequence, with an overall G+C content of 59.7%, revealed, besides genes and open reading frames (ORFs) for nicotine degradation, a complete set of ORFs for enzymes essential for the biosynthesis of the molybdenum dinucleotide cofactor, as well as ORFs related to uptake and utilization of carbohydrates, sarcosine, and amino acids. Of the 165 ORFs, approximately 50% were related to metabolic functions. pAO1 conferred toA. nicotinovoransthe ability to take upl-[14C]nicotine from the medium, with anKmof 5.6 ± 2.2 μM. ORFs of putative nicotine transporters formed a cluster with the gene of thed-nicotine-specific 6-hydroxy-d-nicotine oxidase. ORFs related to replication, chromosome partitioning, and natural transformation functions (dprA) were identified on pAO1. Few ORFs showed similarity to known conjugation-promoting proteins, but pAO1 could be transferred by conjugation to a pAO1-negative strain at a rate of 10−2to 10−3per donor. ORFs with no known function represented approximately 35% of the pAO1 sequence. The positions of insertion sequence elements and composite transposons, corroborated by the G+C content of the pAO1 sequence, suggest a modular composition of the plasmid.
The Membrane Domain of SpoIIIE Is Required for Membrane Fusion during
Bacillus subtilis
Sporulation
Authors: Sharp Marc D. , Pogliano Kit 
Published: March 2003

ABSTRACT

During
Bacillus subtilis
sporulation, SpoIIIE is required for both postseptational chromosome segregation and membrane fusion after engulfment. Here we demonstrate that SpoIIIE must be present in the mother cell to promote membrane fusion and that the N-terminal membrane-spanning segments constitute a minimal membrane fusion domain, as well as direct septal localization.
Identification and Functional Characterization of
Sphingomonas macrogolitabida
Strain TFA Genes Involved in the First Two Steps of the Tetralin Catabolic Pathway
Authors: Moreno-Ruiz Emilia , Hernáez María José , Martínez-Pérez Olga , Santero Eduardo 
Published: March 2003

ABSTRACT

Five genes involved in the two initial steps of the tetralin biodegradation pathway of
Sphingomonas macrogolitabida
strain TFA have been characterized. ThnA1A2 and ThnA3A4, components of the ring-hydroxylating dioxygenase, were encoded in divergently transcribed operons. ThnA1, ThnA2, and ThnA3 were essential for tetralin ring-hydroxylating dioxygenase activity. ThnB was identified as a dehydrogenase required for tetralin biodegradation.
Measurement of Adhesive Forces between Individual
Staphylococcus aureus
MSCRAMMs and Protein-Coated Surfaces by Use of Optical Tweezers
Authors: Simpson Kathryn H. , Bowden Gabriela , Höök Magnus , Anvari Bahman 
Published: March 2003

ABSTRACT

The force required to rupture bonds between individual
Staphylococcus aureus
MSCRAMMs and surfaces coated with extracellular matrix molecules has been quantified by using optical tweezers. The observed binding forces between fibrinogen or fibronectin and
S. aureus
MSCRAMMs occurred as an approximate integer multiple of 20 or 25 pN, respectively.
Excision and Integration of Cassettes by an Integron Integrase ofNitrosomonas europaea
Authors: Léon Grégory , Roy Paul H. 
Published: March 2003

ABSTRACTWe found in the environmental strainNitrosomonas europaeaa chromosomal integron-like structure with an integrase gene,intINeu. We have tested the capacity of the IntINeu integrase to excise and integrate several resistance gene cassettes. The results allow us to consider IntINeu a new functional integron integrase.
Characterization of a Novel Fucose-Regulated Promoter (PfcsK) Suitable for Gene Essentiality and Antibacterial Mode-of-Action Studies inStreptococcus pneumoniae
Authors: Chan Pan F. , O'Dwyer Karen M. , Palmer Leslie M. , Ambrad Jennifer D. , Ingraham Karen A. , So Chi , Lonetto Michael A. , Biswas Sanjoy , Rosenberg Martin , Holmes David J. , Zalacain Magdalena 
Published: March 2003

ABSTRACTThe promoter of theStreptococcus pneumoniaeputative fuculose kinase gene (fcsK), the first gene of a novel fucose utilization operon, is induced by fucose and repressed by glucose or sucrose. When the streptococcal polypeptide deformylase (PDF) gene (def1, encoding PDF) was placed under the control of PfcsK, fucose-dependent growth of theS. pneumoniae(PfcsK::def1) strain was observed, confirming the essential nature of PDF in this organism. The mode of antibacterial action of actinonin, a known PDF inhibitor, was also confirmed with this strain. The endogenous fuculose kinase promoter is a tightly regulated, titratable promoter which will be useful for target validation and for confirmation of the mode of action of novel antibacterial drugs inS. pneumoniae.
Homeodomain proteins MEIS1 and PBXs regulate the lineage-specific transcription of the platelet factor 4 gene
Authors: Okada Yoshiaki , Nagai Ryohei , Sato Takahiro , Matsuura Eri , Minami Takashi , Morita Ikuo , Doi Takefumi 
Published: March 2003

AbstractPlatelet factor 4 (PF4) is expressed during megakaryocytic differentiation. We previously reported that GATA-1 and ETS-1 regulate the rat PF4 promoter and transactivate the PF4 gene. For the present study, we investigated the regulatory elements and their transcription factors responsible for the lineage-specific expression of the PF4 gene. The promoter activities of deletion constructs were evaluated, and a novel regulatory element termed TME (tandem repeat of MEIS1 binding element) (–219 to –182) was defined. Binding proteins to TME were strongly detected in HEL nuclear extracts by electrophoresis mobility shift assay (EMSA), and they were purified by DNA affinity chromatography. By performing Western blottings and supershift assays, the binding proteins were identified as homeodomain proteins, MEIS1, PBX1B, and PBX2. These factors are expressed in megakaryocytes differentiated from CD34+ cells in human cord blood. MEIS1 and PBXs bind to the TME as MEIS1/PBX complexes and activate the PF4 promoter. In nonmegakaryocytic HepG2 cells, GATA-1 and ETS-1 activate the PF4 promoter approximately 10-fold. Surprisingly, we found that additional expression of both MEIS1 and PBX2 multiplied this major activation another 2-fold. This activation was not observed when MEIS1 binding sites in the TME were disrupted. Furthermore, inhibition of the binding of endogenous MEIS1/PBX complexes to the TME decreased the promoter activity by almost one half, in megakaryocytic HEL cells. Thus, these studies demonstrate that the homeodomain proteins, MEIS1, PBX1B, and PBX2, play an important role in megakaryocytic gene expression.
A PAR domain transcription factor is involved in the expression from a hematopoietic-specific promoter for the human LMO2 gene
Authors: Crable Scott C. , Anderson Kathleen P. 
Published: March 2003

AbstractThe transcription factor LMO2 is believed to exert its effect through the formation of protein-protein interactions with other DNA-binding factors such as GATA-1 and TAL1. Although LMO2 has been shown to be critical for the formation of the erythroid cell lineage, the gene is also expressed in a number of nonerythroid tissues. In this report, we demonstrate that the more distal of the 2 promoters for the LMO2 gene is highly restricted in its pattern of expression, directing the hematopoietic-specific expression of this gene. Deletion and mutation analyses have identified a critical cis element in the first untranslated exon of the gene. This element is a consensus-binding site for a small family of basic leucine zipper proteins containing a proline and acidic amino acid–rich (PAR) domain. Although all 3 members of this family are produced in erythroid cells, only 2 of these proteins, thyrotroph embryonic factor and hepatic leukemia factor, can activate transcription from this LMO2 promoter element. These findings represent a novel mechanism in erythroid gene regulation because PAR proteins have not previously been implicated in this process.
Evidence for a role for Gαi1 in mediating weak agonist-induced platelet aggregation in human platelets: reduced Gαi1 expression and defective Gi signaling in the platelets of a patient with a chronic bleeding disorder
Authors: Patel Yatin M. , Patel Kirti , Rahman Salman , Smith Mark P. , Spooner Gillian , Sumathipala Rushika , Mitchell Michael , Flynn Geraldine , Aitken Alexandra , Savidge Geoffrey 
Published: March 2003

AbstractWe have examined platelet functional responses and characterized a novel signaling defect in the platelets of a patient suffering from a chronic bleeding disorder. Platelet aggregation responses stimulated by weak agonists such as adenosine diphosphate (ADP) and adrenaline were severely impaired. In comparison, both aggregation and dense granule secretion were normal following activation with high doses of collagen, thrombin, or phorbol-12 myristate-13 acetate (PMA). ADP, thrombin, or thromboxane A2 (TxA2) signaling through their respective Gq-coupled receptors was normal as assessed by measuring either mobilization of intracellular calcium, diacylglycerol (DAG) generation, or pleckstrin phosphorylation. In comparison, Gi-mediated signaling induced by either thrombin, ADP, or adrenaline, examined by suppression of forskolin-stimulated rise in cyclic AMP (cAMP) was impaired, indicating dysfunctional Gαi signaling. Immunoblot analysis of platelet membranes with specific antiserum against different Gα subunits indicated normal levels of Gαi2,Gαi3,Gαz, and Gαq in patient platelets. However, the Gαi1level was reduced to 25% of that found in normal platelets. Analysis of platelet cDNA and gDNA revealed no abnormality in either the Gαi1 or Gαi2 gene sequences. Our studies implicate the minor expressed Gαi subtype Gαi1 as having an important role in regulating signaling pathways associated with the activation of αIIbβ3 and subsequent platelet aggregation by weak agonists.
Aggravation of endotoxin-induced disseminated intravascular coagulation and cytokine activation in heterozygous protein-C–deficient mice
Authors: Levi Marcel , Dörffler-Melly Janine , Reitsma Pieter , Büller Harry , Florquin Sandrine , van der Poll Tom , Carmeliet Peter 
Published: March 2003

AbstractIn the pathogenesis of sepsis and disseminated intravascular coagulation (DIC), dysfunctional anticoagulant pathways are important. The function of the protein C system in DIC is impaired because of low levels of protein C and down-regulation of thrombomodulin. The administration of (activated) protein C results in an improved outcome in experimental and clinical studies of DIC. It is unknown whether congenital deficiencies in the protein C system are associated with more severe DIC. The aim of the present study was to investigate the effect of a heterozygous deficiency of protein C on experimental DIC in mice. Mice with single-allele targeted disruption of the protein C gene (PC+/–) mice and wild-type littermates (PC+/+) were injected with Escherichia coli endotoxin (50 mg/kg) intraperitoneally. PC+/–mice had more severe DIC, as evidenced by a greater decrease in fibrinogen level and a larger drop in platelet count. Histologic examination showed more fibrin deposition in lungs, kidneys, and liver in mice with a heterozygous deficiency of protein C. Interestingly, PC+/– mice had significantly higher levels of proinflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β, indicating an interaction between the protein C system and the inflammatory response. Survival was lower at 12 and 24 hours after endotoxin in the PC+/– mice. These results confirm the important role of the protein C system in the coagulative-inflammatory response on endotoxemia and may suggest that congenital deficiencies in the protein C system are associated with more severe DIC and adverse outcome in sepsis.
Adhesion of normal and Plasmodium falciparum ring–infected erythrocytes to endothelial cells and the placenta involves the rhoptry-derived ring surface protein-2
Authors: Douki Jean-Bernard Lekana , Sterkers Yvon , Lépolard Catherine , Traoré Boubacar , Costa Fabio T. M. , Scherf Artur , Gysin Jürg 
Published: March 2003

AbstractRecent findings have challenged the current view of Plasmodium falciparum (P falciparum) blood-stage biology by demonstrating the cytoadhesion of early ring-stage–infected erythrocytes (rIEs) to host endothelial cells and placental syncytiotrophoblasts. The adhesion of rIEs was observed only in parasites that bind to the placenta via chondroitin sulfate A (CSA). In this work, a panel of mouse monoclonal antibodies (mAbs) that specifically inhibit cytoadhesion of rIEs but not of mature IEs was generated The previously described ring surface protein 2 (RSP-2), a 42-kDa protein, was identified as the target of the ring-stage–specific mAbs. Time course surface fluorescence experiments revealed a short overlap (approximately 4 hours) of expression between RSP-2 and P falciparum erythrocyte membrane protein 1 (PfEMP1). Their consecutive expression enables IEs to adhere to endothelial cells during the entire blood-stage cycle. During this study, a new phenotype was detected in parasite cultures, the adhesion of normal erythrocytes (nEs) to endothelial cells. All adherent nEs were coated with RSP-2. Immunolocalization studies show that RSP-2 is a rhoptry-derived protein that is discharged onto the erythrocyte membrane during contact with merozoites. Our results identify RSP-2 as a key molecule in sequestration of young blood-stage forms and nEs to endothelial cells.
Prognostic value of pretransplantation positron emission tomography using fluorine 18-fluorodeoxyglucose in patients with aggressive lymphoma treated with high-dose chemotherapy and stem cell transplantation
Authors: Spaepen Karoline , Stroobants Sigrid , Dupont Patrick , Vandenberghe Peter , Maertens Johan , Bormans Guy , Thomas José , Balzarini Jan , De Wolf-Peeters Christine , Mortelmans Luc , Verhoef Gregor 
Published: March 2003

Abstract
The study assessed the prognostic value of fluorine 18-fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) after salvage chemotherapy before high-dose chemotherapy with stem cell transplantation (HDT/SCT) in patients with induction failure or relapsing chemosensitive lymphoma. Retrospective analysis of the clinical and conventional imaging data of 60 patients scheduled for HDT/SCT was performed in parallel with the analysis of the [18F]FDG-PET results. To determine the ability of [18F]FDG-PET to predict clinical outcome, PET images were reread without knowledge of conventional imaging and clinical history. Presence or absence of abnormal [18F]FDG uptake was related to progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier survival analysis. Thirty patients showed a negative [18F]FDG-PET scan before HDT/SCT; 25 of those remained in complete remission, with a median follow-up of 1510 days. Two patients died due to a treatment-related mortality but without evidence of recurrent disease at that time (228-462 days). Only 3 patients had a relapse (median PFS, 1083 days) after a negative [18F]FDG-PET scan. Persistent abnormal [18F]FDG uptake was seen in 30 patients and 26 progressed (median PFS, 402 days); of these 26, 16 died from progressive disease (median OS, 408 days). Four patients are still in complete remission after a positive scan. Comparison between groups indicated a statistically significant association between [18F]FDG-PET findings and PFS (P &lt; .000001) and OS (P &lt; .00002). [18F]FDG-PET has an important prognostic role in the pretransplantation evaluation of patients with lymphoma and enlarges the concept of chemosensitivity used to select patients for HDT/SCT. (Blood. 2003;102:53-59)
A novel ultrasound method for evaluation of collateral development in limb ischemia
Authors: Mohler Emile R , Sehgal Chandra M , Ferrari Victor A , Parmacek Michael , Shih Anthony , Wilensky Robert L 
Published: March 2003

Although clinical studies are underway to evaluate the effectiveness of angiogenesis, there are no validated, non-invasive methods to assess peripheral collateral development. This study was performed to validate a novel ultrasound-based method of assessing collateral formation in a pig model of hindlimb ischemia. Ultrasonography of predefined ultrasound planes was performed on 12 pigs immediately after ligation of the right common femoral artery, and 7, 14, 28 and 42 days thereafter. A custom software program was used to evaluate both color Doppler (CD) and power Doppler (PD) images to generate flow indices. Collateral development was observed with ultrasound as early as 7 days post-arteriectomy and increased dramatically by 28 days. Areas of persistent ischemia resulting from inadequate collateral formation were easily quantified in all images. Collaterals detected on ultrasound were confirmed by angiography and histology, and tissue perfusion by a fluorescent microsphere method. As demonstrated with color and power Doppler measurements, collateral formation is initiated early after ischemic injury in this large juvenile animal model of angiogenesis. This non-invasive method is useful to quantify blood flow, visualize angiogenesis and determine areas of persistent lower limb ischemia, and may have an important role in evaluating new approaches to modulate angiogenesis.
Vascular viewpoint
Authors: Merali Fatima S , Anand Sonia S 
Published: March 2003

Objectives: To determine if immediate surgical repair or regular radiologic surveillance improves survival in patients with small aortic aneurysms. Methods: A total of 1136 people with asymptomatic infrarenal aortic aneurysms (4.0-5.4 cm) with minimal co-morbidities were randomized to standard surgical repair with interposition of a synthetic graft (n = 569) versus radiological surveillance (n = 567). Patients were followed up every 6 months, and those in the surveillance group had CT scan or ultrasound imaging studies. If the aneurysm reached at least 5.5 cm in diameter, or enlarged by 0.7 cm in 6 months, or 1 cm in 1 year, patients in the surveillance group were referred for surgery. The mean duration of follow-up was 4.9 years. Outcomes: The primary outcome was death from any cause, and the primary analysis was by intention to treat. Results: In all, 92.6% patients underwent repair in the immediate surgery group compared with 61.6% repairs in the surveillance group. No significant difference in death from any cause was observed between the immediate repair group (25.1%) and the surveillance group (21.5%) (RR 1.21; 95% CI: 0.95-1.54). Immediate repair did not benefit any of the prespecified groups. Conclusion: No survival benefit is associated with immediate repair of asymptomatic abdominal aortic aneurysms which are less than 5.5 cm.
In-vitro evaluation of bioadhesion in particulate systems and possible improvement using interactive mixtures
Authors: Bredenberg Susanne , Nyström Christer 
Published: March 2003

Abstract
The bioadhesion of tablet components was tested using the fracture method (maximum tensile stress in detaching the sample from mucus membrane) and comparing traditional tablet specimens with powder monolayers. Both nonadhesive excipients and established mucoadhesive materials were investigated. Some nonadhesive materials showed unexpectedly good adhesive properties when tested as tablets but not as powders. Conversely, some bioadhesive materials had unexpectedly low adhesive properties when tested as tablets. Thus, powder specimens of some materials appear to give more realistic results than tablet specimens in this respect. The use of powder specimens seems particularly applicable for testing dispersible tablets intended fortransmucosal absorption. Potential for increasing the bioadhesive properties of coarse, nonadhesive carrier particles by coating them with fine particles of bioadhesive materials during dry mixing (forming interactive mixtures) was also studied. The tensile strength of the adhesive bond between the mucosa and the nonadhesive excipients was improved when fine cross-linked carboxymethyl cellulose sodium (Ac-Di-Sol) particles were added. The addition of increased proportions of Ac-Di-Sol initially improved the bioadhesive properties until a plateau was reached. A standardised test of bioadhesive capacity could therefore involve the addition of fine bioadhesive powders to coarse carriers in proportions close to those providing monoparticulate surface coverage. Interactive mixtures such as these may also offer potential as a tool for use in the development of bioadhesive drug formulations.
Therapeutic equivalence of a low dose artemisinin formulation in falciparum malaria patients
Authors: Wong J W , Yuen K H , Nagappan S , Shahul W S , Ho S S David , Gan E K , Toh W T 
Published: March 2003

Abstract
We have evaluated the therapeutic equivalence of a β-cyclodextrin–artemisinin complex at an artemisinin dose of 150 mg, with a commercial reference preparation, Artemisinin 250 at a recommended dose of 250 mg. One hundred uncomplicated falciparum malarial patients were randomly assigned to orally receive either β-cyclo-extrin–artemisinin complex (containing 150 mg artemisinin) twice daily for five days or the active comparator (containing 250 mg artemisinin) twice daily for five days. The patients were hospitalized for seven days and were required to attend follow up assessments on days 14, 21, 28 and 35. All patients in both treatment groups were cured of the infection and achieved therapeutic success. At day seven of treatment, all patient blood was clear of the parasites and the sublingual temperature of all patients was less than 37.5°C. Moreover, the parasite clearance time in both treatment groups was similar, being approximately three days after initiation of treatment. Comparable plasma artemisinin concentrations were observed between patients in both treatment groups at 1.5 and 3.0 h, although slightly higher levels were obtained with patients in the β-cyclodextrin–artemisinin complex-treated group. The β-cyclodextrin–artemisinin complex at a dose of 150 mg artemisinin was therapeutically equivalent to 250 mg Artemisinin 250. Additionally, patients receiving β-cyclodextrin–artemisinin complex showed less variability in their plasma artemisinin concentrations at 1.5 h post-dosing, which suggested a more consistent rate of drug absorption.