bluuebunny/crossref_metadata_2025_split huggingface dataset:
Involvement of
Streptococcus gordonii
Beta-Glucoside Metabolism Systems in Adhesion, Biofilm Formation, and In Vivo Gene Expression
Authors: Kiliç Ali O. , Tao Lin , Zhang Yongshu , Lei Yu , Khammanivong Ali , Herzberg Mark C. 
Published: June 2004

ABSTRACT

Streptococcus gordonii
genes involved in beta-glucoside metabolism are induced in vivo on infected heart valves during experimental endocarditis and in vitro during biofilm formation on saliva-coated hydroxyapatite (sHA). To determine the roles of beta-glucoside metabolism systems in biofilm formation, the loci of these induced genes were analyzed. To confirm the function of genes in each locus, strains were constructed with gene inactivation, deletion, and/or reporter gene fusions. Four novel systems responsible for beta-glucoside metabolism were identified, including three phosphoenolpyruvate-dependent phosphotransferase systems (PTS) and a binding protein-dependent sugar uptake system for metabolizing multiple sugars, including beta-glucosides. Utilization of arbutin and esculin, aryl-beta-glucosides, was defective in some mutants. Esculin and oligochitosaccharides induced genes in one of the three beta-glucoside metabolism PTS and in four other genetic loci. Mutation of genes in any of the four systems affected in vitro adhesion to sHA, biofilm formation on plastic surfaces, and/or growth rate in liquid medium. Therefore, genes associated with beta-glucoside metabolism may regulate
S. gordonii
in vitro adhesion, biofilm formation, growth, and in vivo colonization.
Multilocus Sequence Typing ofStreptococcus pyogenesRepresenting Most KnownemmTypes and Distinctions among Subpopulation Genetic Structures
Authors: McGregor Karen F. , Spratt Brian G. , Kalia Awdhesh , Bennett Alicia , Bilek Nicole , Beall Bernard , Bessen Debra E. 
Published: June 2004

ABSTRACTA long-term goal is to characterize the full range of genetic diversity withinStreptococcus pyogenesas it exists in the world today. Since theemmlocus is subject to strong diversifying selection,emmtype was used as a guide for identifying a genetically diverse set of strains. This report contains a description of multilocus sequence typing based on seven housekeeping loci for 495 isolates representing 158emmtypes, yielding 238 unique combinations of sequence type andemmtype. A genotypic marker for tissue site preference (emmpattern) revealed that only 17% of theemmtypes displayed the marker representing strong preference for infection at the throat and that 39% ofemmtypes had the marker for skin tropism, whereas 41% ofemmtypes harbored the marker for no obvious tissue site preference. As a group, theemmtypes bearing theemmpattern marker indicative of no obvious tissue site preference were far less likely to have two distinctemmtypes associated with the same sequence type than either of the two subpopulations having markers for strong tissue tropisms (P< 0.002). In addition, all genetic diversification events clearly ascribed to a recombinational mechanism involved strains of only two of theemmpattern-defined subpopulations, those representing skin specialists and generalists. The findings suggest that the population genetic structure differs for the tissue-defined subpopulations ofS. pyogenes. The observed differences may partly reflect differential host immune selection pressures.
P Pilus Assembly Motif Necessary for Activation of the CpxRA Pathway by PapE in
Escherichia coli
Authors: Lee Yvonne M. , DiGiuseppe Patricia A. , Silhavy Thomas J. , Hultgren Scott J. 
Published: June 2004

ABSTRACT
P pilus biogenesis occurs via the highly conserved chaperone-usher pathway, and assembly is monitored by the CpxRA two-component signal transduction pathway. Structural pilus subunits consist of an N-terminal extension followed by an incomplete immunoglobulin-like fold that is missing a C-terminal seventh beta strand. In the pilus fiber, the immunoglobulin-like fold of each pilin is completed by the N-terminal extension of its neighbor. Subunits that do not get incorporated into the pilus fiber are driven “OFF-pathway.” In this study, we found that PapE was the only OFF-pathway nonadhesin P pilus subunit capable of activating Cpx. Manipulation of the PapE structure by removing, relocating within the protein, or swapping its N-terminal extension with that of other subunits altered the protein's self-associative and Cpx-activating properties. The self-association properties of the new subunits were dictated by the specific N-terminal extension provided and were consistent with the order of the subunits in the pilus fiber. However, these aggregation properties did not directly correlate with Cpx induction. Cpx activation instead correlated with the presence or absence of an N-terminal extension in the PapE pilin structure. Removal of the N-terminal extension of PapE was sufficient to abolish Cpx activation. Replacement of an N-terminal extension at either the amino or carboxyl terminus restored Cpx induction. Thus, the data presented in this study argue that PapE has features inherent in its structure or during its folding that act as specific inducers of Cpx signal transduction.
Genomic DNA Microarray Analysis: Identification of New Genes Regulated by Light Color in the CyanobacteriumFremyella diplosiphon
Authors: Stowe-Evans Emily L. , Ford James , Kehoe David M. 
Published: June 2004

ABSTRACTMany cyanobacteria use complementary chromatic adaptation to efficiently utilize energy from both green and red regions of the light spectrum during photosynthesis. Although previous studies have shown that acclimation to changing light wavelengths involves many physiological responses, research to date has focused primarily on the expression and regulation of genes that encode proteins of the major photosynthetic light-harvesting antennae, the phycobilisomes. We have used two-dimensional gel electrophoresis and genomic DNA microarrays to expand our understanding of the physiology of acclimation to light color in the cyanobacteriumFremyella diplosiphon. We found that the levels of nearly 80 proteins are altered in cells growing in green versus red light and have cloned and positively identified 17 genes not previously known to be regulated by light color in any species. Among these are homologs of genes present in many bacteria that encode well-studied proteins lacking clearly defined functions, such astspO, which encodes a tryptophan-rich sensory protein, and homologs of genes encoding proteins of clearly defined function in many species, such asnblAandchlL, encoding phycobilisome degradation and chlorophyll biosynthesis proteins, respectively. Our results suggest novel roles for several of these gene products and highly specialized, unique uses for others.
Mutational Analysis and Biochemical Characterization of theBurkholderia thailandensisDW503 Quorum-Sensing Network
Authors: Ulrich Ricky L. , Hines Harry B. , Parthasarathy N. , Jeddeloh Jeffrey A. 
Published: June 2004

ABSTRACTNumerous gram-negative bacteria communicate and regulate gene expression through a cell density-responsive mechanism termed quorum sensing (QS), which involves the synthesis and perception of diffusibleN-acyl-homoserine lactones (AHL). In this study we genetically and physiologically characterized theBurkholderia thailandensisDW503 QS network. In silico analysis of theB. thailandensisgenome revealed the presence of at least three AHL synthases (AHS) and five transcriptional regulators belonging to the LuxIR family of proteins. Mass spectrometry demonstrated that wild-typeB. thailandensissynthesizesN-hexanoyl-homoserine lactone (C6-HSL),N-octanoyl-homoserine lactone (C8-HSL), andN-decanoyl-homoserine lactone (C10-HSL). Mutation of thebtaI1(luxI) AHS gene prevented accumulation of C8-HSL in culture supernatants, enhanced beta-hemolysis of sheep erythrocytes, increased lipase production, and altered colony morphology on swarming and twitching motility plates. Disruption of thebtaI3(luxI) AHS prevented biosynthesis of C6-HSL and increased lipase production and beta-hemolysis, whereas mutagenesis of thebtaI2(luxI) allele eliminated C10-HSL accumulation and reduced lipase production. Complementation of thebtaI1andbtaI3mutants fully restored the synthesis of C8-HSL and C6-HSL to parental levels. In contrast, mutagenesis of thebtaR1,btaR3,btaR4, andbtaR5(luxR) transcriptional regulators had no effect on AHL accumulation, enhanced lipase production, and resulted in extensive beta-hemolysis on sheep blood agar plates. Furthermore, interruption of thebtaI1,btaR1, andbtaR3genes altered colony morphology on twitching and swarming motility plates and induced pigmentation. Additionally, phenotypic microarray analysis indicated that QS inB. thailandensisboth positively and negatively affects the metabolism of numerous substrates, including citric acid, formic acid, glucose 6-phosphate, capric acid, γ-hydroxybutyric acid, andd-arabinose. These results demonstrate that mutagenesis of theB. thailandensisQS system affects various cellular processes, including lipase production, swarming and twitching motility, beta-hemolysis of sheep erythrocytes, and carbon metabolism and/or transport.
σ54Enhancer Binding Proteins andMyxococcus xanthusFruiting Body Development
Authors: Jakobsen Jimmy S. , Jelsbak Lars , Jelsbak Lotte , Welch Roy D. , Cummings Craig , Goldman Barry , Stark Elizabeth , Slater Steve , Kaiser Dale 
Published: June 2004

ABSTRACTA search of the M1genome sequence, which includes 97% of theMyxococcus xanthusgenes, identified 53 sequence homologs of σ54-dependent enhancer binding proteins (EBPs). A DNA microarray was constructed from the M1genome that includes those homologs and 318 otherM. xanthusgenes for comparison. To screen the developmental program with this array, an RNA extract from growing cells was compared with one prepared from developing cells at 12 h. Previous reporter studies had shown thatM. xanthushas initiated development and has begun to express many developmentally regulated genes by 12 h. The comparison revealed substantial increases in the expression levels of 11 transcription factors that may respond to environmental stimuli. Six of the 53 EBP homologs were expressed at significantly higher levels at 12 h of development than during growth. Three were previously unknown genes, and they were inactivated to look for effects on fruiting body development. One knockout mutant produced fruiting bodies of abnormal shape that depended on the composition of the medium.
tonB3
Is Required for Normal Twitching Motility and Extracellular Assembly of Type IV Pili
Authors: Huang Bixing , Ru Kelin , Yuan Zheng , Whitchurch Cynthia B. , Mattick John S. 
Published: June 2004

ABSTRACT

Three mutants with Tn
5
-B21 insertion in
tonB3
(PA0406) of
Pseudomonas aeruginosa
exhibited defective twitching motility and reduced assembly of extracellular pili. These defects could be complemented with wild-type
tonB3
.
Point Mutations in Transmembrane Helices 2 and 3 of ExbB and TolQ Affect Their Activities inEscherichia coliK-12
Authors: Braun Volkmar , Herrmann Christina 
Published: June 2004

ABSTRACTReplacement of glutamate 176, the only charged amino acid in the third transmembrane helix of ExbB, with alanine (E176A) abolished ExbB activity in all determined ExbB-dependent functions ofEscherichia coli. Combination of the mutations T148A in the second transmembrane helix and T181A in the third transmembrane helix, proposed to form part of a proton pathway through ExbB, also resulted in inactive ExbB. E176 and T148 are strictly conserved in ExbB and TolQ proteins, and T181 is almost strictly conserved in ExbB, TolQ, and MotA.
Haemophilus somnus
Possesses Two Systems for Acquisition of Transferrin-Bound Iron
Authors: Ekins Andrew , Bahrami Fariborz , Sijercic Ada , Maret Deborah , Niven Donald F. 
Published: June 2004

ABSTRACT

Haemophilus somnus
strain 649 was found to acquire iron from ovine, bovine, and goat transferrins (Tfs). Expression of Tf receptors, as evaluated by solid-phase binding assays, required the organisms to be grown under iron-restricted conditions in the presence of Tf. Competition binding assays revealed the presence of two distinct Tf-binding receptor systems, one specific for bovine Tf and the other capable of binding all three ruminant Tfs. Affinity isolation procedures using total membranes yielded three putative bovine Tf-binding polypeptides and one putative ovine and goat Tf-binding polypeptide. PCR amplification followed by DNA sequence analyses revealed that
H. somnus
strain 649 possesses genes that encode a bipartite TbpA-TbpB receptor along with a homolog of the
Histophilus ovis
single-component TbpA receptor. Expression of TbpB and the single-component TbpA would appear to be subject to a form of phase variation involving homopolymeric nucleotide tracts within the structural genes.
Nitrosomonas europaea
Expresses a Nitric Oxide Reductase during Nitrification
Authors: Beaumont Hubertus J. E. , van Schooten Bas , Lens Sylvia I. , Westerhoff Hans V. , van Spanning Rob J. M. 
Published: June 2004

ABSTRACT

In this paper, we report the identification of a
norCBQD
gene cluster that encodes a functional nitric oxide reductase (Nor) in
Nitrosomonas europaea
. Disruption of the
norB
gene resulted in a strongly diminished nitric oxide (NO) consumption by cells and membrane protein fractions, which was restored by the introduction of an intact
norCBQD
gene cluster in
trans
. NorB-deficient cells produced amounts of nitrous oxide (N
2
O) equal to that of wild-type cells. NorCB-dependent activity was present during aerobic growth and was not affected by the inactivation of the putative
fnr
gene. The findings demonstrate the presence of an alternative site of N
2
O production in
N. europaea
.
Nongenomic effects of 17β-estradiol in human platelets: potentiation of thrombin-induced aggregation through estrogen receptor β and Src kinase
Authors: Moro Laura , Reineri Stefania , Piranda Daniela , Pietrapiana Daniela , Lova Paolo , Bertoni Alessandra , Graziani Andrea , Defilippi Paola , Canobbio Ilaria , Torti Mauro , Sinigaglia Fabiola 
Published: June 2004

AbstractThe impact of estrogens on the cardiovascular system and their ability to regulate platelet function are matters of controversy. The recent finding that estrogen receptors are expressed in human platelets renders these cells an excellent model for studying the nongenomic effects of these hormones. In this work, we investigated 17β-estradiol–dependent signaling in platelets from adult healthy men. 17β-estradiol caused the rapid phosphorylation of the tyrosine kinases Src and Pyk2 and the formation of a signaling complex, which included Src, Pyk2, and the phosphatidylinositol 3-kinase. Both these events were dependent on estrogen receptor β engagement. We found that estrogen receptor β was membrane-associated in platelets. On treatment with 17β-estradiol, Src and Pyk2 activation occurred in the membrane fraction but not in the cytosol. In contrast, no significant activation of phosphatidylinositol 3-kinase was detected in estrogen-treated platelets. 17β-estradiol did not induce any platelet response directly, but it strongly potentiated the activation of integrin αIIbβ3 and the platelet aggregation induced by subthreshold concentrations of thrombin. These effects were dependent on estrogen receptor β recruitment and were associated with a strong synergistic effect with thrombin on Src activation. Taken together, these results indicate that 17β-estradiol can modulate platelet function by exercising a proaggregating role.
Long-term survival benefit and improved complete cytogenetic and molecular response rates with imatinib mesylate in Philadelphia chromosome–positive chronic-phase chronic myeloid leukemia after failure of interferon-α
Authors: Kantarjian Hagop M. , Cortes Jorge E. , O'Brien Susan , Luthra Rajyalakshmi , Giles Francis , Verstovsek Srdan , Faderl Stefan , Thomas Deborah , Garcia-Manero Guillermo , Rios Mary Beth , Shan Jianqin , Jones Dan , Talpaz Moshe 
Published: June 2004

AbstractWe reviewed 261 patients with chronicphase chronic myelogenous leukemia (CML) after interferon-α (IFN-α) failure treated with imatinib mesylate 400 mg daily. With a median follow-up time of 45 months, the major cytogenetic response rate was 73% and the complete cytogenetic response rate 63%. The estimated 4-year survival rate was 86%. Multivariate analysis for survival identified hematologic resistance to IFN-α (P = .01), splenomegaly (P = .03), and lack of any cytogenetic response after 3 months of therapy (P = .01) to have independent poor prognostic significance. Patients could be divided into good(no adverse factors), intermediate(1 adverse factor), and poor-risk groups (2 or 3 adverse factors; 12% of patients) with estimated 4-year survival rates of 96%, 86%, and 49%, respectively (P &lt; .000 01). The 4-year cumulative major molecular response (quantitative reverse transcriptase–polymerase chain reaction [Q-PCR] = BCR-ABL/ABL less than 0.05%) rate was 43% and complete molecular response rate (BCR-ABL undetectable) 26%. Compared with a historical group of 251 similar patients treated with nonimatinib therapies, imatinib mesylate was associated with a better 4-year survival rate (86% versus 43%; P &lt; .0001); the survival advantage was confirmed by multivariate analysis (hazard ratio, 0.19; P &lt; .0001).
Brazilian Sepsis Epidemiological Study (BASES study)
Authors: Silva Eliézer , Pedro Marcelo de Almeida , Sogayar Ana Cristina Beltrami , Mohovic Tatiana , Silva Carla Likade Oliveira , Janiszewski Mariano , Cal Ruy Guilherme Rodrigues , de Sousa Érica Fernandes , Abe Thereza Phitoe , de Andrade Joel , de Matos Jorge Dias , Rezende Ederlon , Assunção Murillo , Avezum Álvaro , Rocha Patrícia CS , de Matos Gustavo Faissol Janot , Bento André Moreira , Corrêa Alice Danielli , Vieira Paulo Cesar Bastos , Knobel Elias 
Published: June 2004

Abstract
Introduction
Consistent data about the incidence and outcome of sepsis in Latin American intensive care units (ICUs), including Brazil, are lacking. This study was designed to verify the actual incidence density and outcome of sepsis in Brazilian ICUs. We also assessed the association between the Consensus Conference criteria and outcome

Methods
This is a multicenter observational cohort study performed in five private and public, mixed ICUs from two different regions of Brazil. We prospectively followed 1383 adult patients consecutively admitted to those ICUs from May 2001 to January 2002, until their discharge, 28th day of stay, or death. For all patients we collected the following data at ICU admission: age, gender, hospital and ICU admission diagnosis, APACHE II score, and associated underlying diseases. During the following days, we looked for systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, and septic shock criteria, as well as recording the sequential organ failure assessment score. Infection was diagnosed according to CDC criteria for nosocomial infection, and for community-acquired infection, clinical, radiological and microbiological parameters were used.

Results
For the whole cohort, median age was 65.2 years (49–76), median length of stay was 2 days (1–6), and the overall 28-day mortality rate was 21.8%. Considering 1383 patients, the incidence density rates for sepsis, severe sepsis and septic shock were 61.4, 35.6 and 30.0 per 1000 patient-days, respectively. The mortality rate of patients with SIRS, sepsis, severe sepsis and septic shock increased progressively from 24.3% to 34.7%, 47.3% and 52.2%, respectively. For patients with SIRS without infection the mortality rate was 11.3%. The main source of infection was lung/respiratory tract.

Conclusion
Our preliminary data suggest that sepsis is a major public health problem in Brazilian ICUs, with an incidence density about 57 per 1000 patient-days. Moreover, there was a close association between ACCP/SCCM categories and mortality rate.
American Society of Clinical Oncology Recommendations on Adjuvant Chemotherapy for Stage II Colon Cancer
Authors: Benson Al B. , Schrag Deborah , Somerfield Mark R. , Cohen Alfred M. , Figueredo Alvaro T. , Flynn Patrick J. , Krzyzanowska Monika K. , Maroun Jean , McAllister Pamela , Van Cutsem Eric , Brouwers Melissa , Charette Manya , Haller Daniel G. 
Published: June 2004

Purpose To address whether all medically fit patients with curatively resected stage II colon cancer should be offered adjuvant chemotherapy as part of routine clinical practice, to identify patients with poor prognosis characteristics, and to describe strategies for oncologists to use to discuss adjuvant chemotherapy in practice. Methods An American Society of Clinical Oncology Panel, in collaboration with the Cancer Care Ontario Practice Guideline Initiative, reviewed pertinent information from the literature through May 2003. Results A literature-based meta-analysis found no evidence of a statistically significant survival benefit of adjuvant chemotherapy for stage II patients. Recommendations The routine use of adjuvant chemotherapy for medically fit patients with stage II colon cancer is not recommended. However, there are populations of patients with stage II disease that could be considered for adjuvant therapy, including patients with inadequately sampled nodes, T4 lesions, perforation, or poorly differentiated histology. Conclusion Direct evidence from randomized controlled trials does not support the routine use of adjuvant chemotherapy for patients with stage II colon cancer. Patients and oncologists who accept the relative benefit in stage III disease as adequate indirect evidence of benefit for stage II disease are justified in considering the use of adjuvant chemotherapy, particularly for those patients with high-risk stage II disease. The ultimate clinical decision should be based on discussions with the patient about the nature of the evidence supporting treatment, the anticipated morbidity of treatment, the presence of high-risk prognostic features on individual prognosis, and patient preferences. Patients with stage II disease should be encouraged to participate in randomized trials.
ABVD Plus Subtotal Nodal Versus Involved-Field Radiotherapy in Early-Stage Hodgkin's Disease: Long-Term Results
Authors: Bonadonna Gianni , Bonfante Valeria , Viviani Simonetta , Di Russo Anna , Villani Fabrizio , Valagussa Pinuccia 
Published: June 2004

Purpose Radiation therapy (RT) alone can cure more than 80% of all patients with pathologic stage IA, IB, and IIA Hodgkin's disease, but some prognostic factors unfavorably affect treatment outcome. Combined-modality approaches improved results compared with RT, but the optimal extent of RT fields when combined with chemotherapy warranted additional evaluation. Patients and Methods In February 1990, we activated a prospective trial in patients with early, clinically staged Hodgkin's disease to assess efficacy and tolerability of four cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) followed by either subtotal nodal plus spleen irradiation (STNI) or involved-field radiotherapy (IFRT). Results Main patient characteristics were fairly well balanced between the two arms. Complete remission was achieved in 100% and in 97% of patients, respectively. The 12-year freedom from progression rates were 93% (95% CI, 83% to 100%) after ABVD and STNI, and 94% (95% CI, 88% to 100%) after ABVD and IFRT, whereas the figures for overall survival were 96% (95% CI, 91% to 100%) and 94% (95% CI, 89% to 100%), respectively. Apart from three patients who developed second malignancies in the STNI arm, treatment-related morbidities were mild. Conclusion Present long-term findings suggest that, after four cycles of ABVD, IFRT can achieve a worthwhile outcome. The limited size of our patient sample, however, had no adequate statistical power to test for noninferiority of IFRT versus STNI. Despite this, ABVD followed by IFRT can be considered an effective and safe modality in early Hodgkin's disease with both favorable and unfavorable presentation.