bluuebunny/crossref_metadata_2025_split huggingface dataset:
Why Does
Escherichia coli
Grow More Slowly on Glucosamine than on
N
-Acetylglucosamine? Effects of Enzyme Levels and Allosteric Activation of GlcN6P Deaminase (NagB) on Growth Rates
Authors: Álvarez-Añorve Laura I. , Calcagno Mario L. , Plumbridge Jacqueline 
Published: April 2005

ABSTRACT

Wild-type
Escherichia coli
grows more slowly on glucosamine (GlcN) than on
N
-acetylglucosamine (GlcNAc) as a sole source of carbon. Both sugars are transported by the phosphotransferase system, and their 6-phospho derivatives are produced. The subsequent catabolism of the sugars requires the allosteric enzyme glucosamine-6-phosphate (GlcN6P) deaminase, which is encoded by
nagB
, and degradation of GlcNAc also requires the
nagA
-encoded enzyme,
N
-acetylglucosamine-6-phosphate (GlcNAc6P) deacetylase. We investigated various factors which could affect growth on GlcN and GlcNAc, including the rate of GlcN uptake, the level of induction of the
nag
operon, and differential allosteric activation of GlcN6P deaminase. We found that for strains carrying a wild-type deaminase (
nagB
) gene, increasing the level of the NagB protein or the rate of GlcN uptake increased the growth rate, which showed that both enzyme induction and sugar transport were limiting. A set of point mutations in
nagB
that are known to affect the allosteric behavior of GlcN6P deaminase in vitro were transferred to the
nagB
gene on the
Escherichia coli
chromosome, and their effects on the growth rates were measured. Mutants in which the substrate-induced positive cooperativity of NagB was reduced or abolished grew even more slowly on GlcN than on GlcNAc or did not grow at all on GlcN. Increasing the amount of the deaminase by using a
nagC
or
nagA
mutation to derepress the
nag
operon improved growth. For some mutants, a
nagA
mutation, which caused the accumulation of the allosteric activator GlcNAc6P and permitted allosteric activation, had a stronger effect than
nagC
. The effects of the mutations on growth in vivo are discussed in light of their in vitro kinetics.
Functional Characterization of WaaL, a Ligase Associated with Linking O-Antigen Polysaccharide to the Core of
Pseudomonas aeruginosa
Lipopolysaccharide
Authors: Abeyrathne Priyanka D. , Daniels Craig , Poon Karen K. H. , Matewish Mauricia J. , Lam Joseph S. 
Published: April 2005

ABSTRACT

The O antigen of
Pseudomonas aeruginosa
B-band lipopolysaccharide is synthesized by assembling O-antigen-repeat units at the cytoplasmic face of the inner membrane by nonprocessive glycosyltransferases, followed by polymerization on the periplasmic face. The completed chains are covalently attached to lipid A core by the O-antigen ligase, WaaL. In
P. aeruginosa
the process of ligating these O-antigen molecules to lipid A core is not clearly defined, and an O-antigen ligase has not been identified until this study. Using the sequence of
waaL
from
Salmonella enterica
as a template in a BLAST search, a putative
waaL
gene was identified in the
P. aeruginosa
genome. The candidate gene was amplified and cloned, and a chromosomal knockout of PAO1
waaL
was generated. Lipopolysaccharide (LPS) from this mutant is devoid of B-band O-polysaccharides and semirough (SR-LPS, or core-plus-one O-antigen). The mutant PAO1
waaL
is also deficient in the production of A-band polysaccharide, a homopolymer of
d
-rhamnose. Complementation of the mutant with pPAJL4 containing
waaL
restored the production of both A-band and B-band O antigens as well as SR-LPS, indicating that the knockout was nonpolar and
waaL
is required for the attachment of O-antigen repeat units to the core. Mutation of
waaL
in PAO1 and PA14, respectively, could be complemented with
waaL
from either strain to restore wild-type LPS production. The
waaL
mutation also drastically affected the swimming and twitching motilities of the bacteria. These results demonstrate that
waaL
in
P. aeruginosa
encodes a functional O-antigen ligase that is important for cell wall integrity and motility of the bacteria.
RNase/Anti-RNase Activities of the BacterialparDToxin-Antitoxin System
Authors: Muñoz-Gómez Ana J. , Lemonnier Marc , Santos-Sierra Sandra , Berzal-Herranz Alfredo , Díaz-Orejas Ramón 
Published: April 2005

ABSTRACTThe bacterialparDtoxin-antitoxin system of plasmid R1 encodes two proteins, the Kid toxin and its cognate antitoxin, Kis. Kid cleaves RNA and inhibits protein synthesis and cell growth inEscherichia coli. Here, we show that Kid promotes RNA degradation and inhibition of protein synthesis in rabbit reticulocyte lysates. These new activities of the Kid toxin were counteracted by the Kis antitoxin and were not displayed by the KidR85W variant, which is nontoxic inE. coli. Moreover, while Kid cleaved single- and double-stranded RNA with a preference for UAA or UAC triplets, KidR85W maintained this sequence preference but hardly cleaved double-stranded RNA. Kid was formerly shown to inhibit DNA replication of the ColE1 plasmid. Here we provide in vitro evidence that Kid cleaves the ColE1 RNA II primer, which is required for the initiation of ColE1 replication. In contrast, KidR85W did not affect the stability of RNA II, nor did it inhibit the in vitro replication of ColE1. Thus, the endoribonuclease and the cytotoxic and DNA replication-inhibitory activities of Kid seem tightly correlated. We propose that the spectrum of action of this toxin extends beyond the sole inhibition of protein synthesis to control a broad range of RNA-regulated cellular processes.
The Genome of S-PM2, a “Photosynthetic” T4-Type Bacteriophage That Infects Marine
Synechococcus
Strains
Authors: Mann Nicholas H. , Clokie Martha R. J. , Millard Andrew , Cook Annabel , Wilson William H. , Wheatley Peter J. , Letarov Andrey , Krisch H. M. 
Published: April 2005

ABSTRACT

Bacteriophage S-PM2 infects several strains of the abundant and ecologically important marine cyanobacterium
Synechococcus
. A large lytic phage with an isometric icosahedral head, S-PM2 has a contractile tail and by this criterion is classified as a myovirus (1). The linear, circularly permuted, 196,280-bp double-stranded DNA genome of S-PM2 contains 37.8% G+C residues. It encodes 239 open reading frames (ORFs) and 25 tRNAs. Of these ORFs, 19 appear to encode proteins associated with the cell envelope, including a putative S-layer-associated protein. Twenty additional S-PM2 ORFs have homologues in the genomes of their cyanobacterial hosts. There is a group I self-splicing intron within the gene encoding the D1 protein. A total of 40 ORFs, organized into discrete clusters, encode homologues of T4 proteins involved in virion morphogenesis, nucleotide metabolism, gene regulation, and DNA replication and repair. The S-PM2 genome encodes a few surprisingly large (e.g., 3,779 amino acids) ORFs of unknown function. Our analysis of the S-PM2 genome suggests that many of the unknown S-PM2 functions may be involved in the adaptation of the metabolism of the host cell to the requirements of phage infection. This hypothesis originates from the identification of multiple phage-mediated modifications of the host's photosynthetic apparatus that appear to be essential for maintaining energy production during the lytic cycle.
Molecular Determinants for PspA-Mediated Repression of the AAA Transcriptional Activator PspF
Authors: Elderkin Sarah , Bordes Patricia , Jones Susan , Rappas Mathieu , Buck Martin 
Published: April 2005

ABSTRACTTheEscherichia coliphage shock protein system (pspABCDEoperon andpspGgene) is induced by numerous stresses related to the membrane integrity state. Transcription of thepspgenes requires the RNA polymerase containing the σ54subunit and the AAA transcriptional activator PspF. PspF belongs to an atypical class of σ54AAA activators in that it lacks an N-terminal regulatory domain and is instead negatively regulated by another regulatory protein, PspA. PspA therefore represses its own expression. The PspA protein is distributed between the cytoplasm and the inner membrane fraction. In addition to its transcriptional inhibitory role, PspA assists maintenance of the proton motive force and protein export. Several lines of in vitro evidence indicate that PspA-PspF interactions inhibit the ATPase activity of PspF, resulting in the inhibition of PspF-dependent gene expression. In this study, we characterize sequences within PspA and PspF crucial for the negative effect of PspA upon PspF. Using a protein fragmentation approach, we show that the integrity of the three putative N-terminal α-helical domains of PspA is crucial for the role of PspA as a negative regulator of PspF. A bacterial two-hybrid system allowed us to provide clear evidence for an interaction inE. colibetween PspA and PspF in vivo, which strongly suggests that PspA-directed inhibition of PspF occurs via an inhibitory complex. Finally, we identify a single PspF residue that is a binding determinant for PspA.
Identification and Characterization of Genes Required for Competence in
Neisseria meningitidis
Authors: Sun Yao-Hui , Exley Rachel , Li Yanwen , Goulding David , Tang Christoph 
Published: April 2005

ABSTRACT

We have identified genes required for competence of
Neisseria meningitidis
, a naturally transformable human pathogen. Although not comprehensive, our analysis identified competence-defective mutants with transposon insertions in genes not previously implicated in this process in
Neisseria
.
The use of biomarkers of exposure ofN,N-dimethylformamide in health risk assessment and occupational hygiene in the polyacrylic fibre industry
Authors: Käfferlein H U , Ferstl C , Burkhart-Reichl A , Hennebrüder K , Drexler H , Brüning T , Angerer J 
Published: April 2005

Background:N,N-dimethylformamide (DMF) was recently prioritised for field studies by the National Toxicology Program based on the potency of its reproductive toxic effects.Aims:To measure accurately exposure to DMF in occupational settings.Methods:In 35 healthy workers employed in the polyacrylic fibre industry,N-methylformamide (NMF) andN-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) in urine, andN-methylcarbamoylated haemoglobin (NMHb) in blood were measured. Workplace documentation and questionnaire information were used to categorise workers in groups exposed to low, medium, and high concentrations of DMF.Results:All three biomarkers can be used to identify occupational exposure to DMF. However, only the analysis of NMHb could accurately distinguish between workers exposed to different concentrations of DMF. The median concentrations were determined to be 55.1, 122.8, and 152.6 nmol/g globin in workers exposed to low, medium, and high concentrations of DMF, respectively. It was possible by the use of NMHb to identify all working tasks with increased exposure to DMF. While fibre crimpers were found to be least exposed to DMF, persons washing, dyeing, or towing the fibres were found to be highly exposed to DMF. In addition, NMHb measurements were capable of uncovering working tasks, which previously were not associated with increased exposure to DMF; for example, the person preparing the fibre forming solution.Conclusions:Measurement of NMHb in blood is recommended rather than measurement of NMF and AMCC in urine to accurately assess exposure to DMF in health risk assessment. However, NMF and AMCC are useful biomarkers for occupational hygiene intervention. Further investigations regarding toxicity of DMF should focus on highly exposed persons in the polyacrylic fibre industry. Additional measurements in occupational settings other than the polyacrylic fibre industry are also recommended, since the population at risk and the production volume of DMF are high.
Blood lead and erythrocyte protoporphyrin levels in association with smoking and personal hygienic behaviour among lead exposed workers
Authors: Karita K , Nakao M , Ohwaki K , Yamanouchi Y , Nishikitani M , Nomura K , Sato M , Yano E 
Published: April 2005

Aims:To investigate the effects of smoking and personal hygienic behaviour on blood lead (BPb) and free erythrocyte protoporphyrin levels (FEP) in lead exposed workers.Methods:Subjects were 105 lead exposed male workers in a battery recycling plant during the years 2000–03. BPb and FEP were measured as part of the ongoing occupational surveillance. Each worker completed a questionnaire for assessment of smoking and four measures of personal hygienic behaviour (glove and mask use, hand and face washing before meals during working hours).Results:Statistically significant decreases in mean BPb and FEP occurred during the three years. The proportion of BPb reduction in the non-smoking workers was significantly higher (mean 24.3%) than in the smoking workers (15.3%). When the workers were classified into three groups (excellent, good, and poor) based on the four personal hygienic behavioural indicators, the greatest decreases of BPb and FEP were observed in the non-smoking workers of the excellent group.Conclusions:The consistent use of protection devices and cleanliness at work appeared to contribute to the lowering of BPb and FEP. Cessation of smoking in the workplace was also of importance.
The Civil Code of the Russian Federation from Foreign and Comparative Law Perspectives: An Introduction
Authors: Sahlas Peter 
Published: April 2005

AbstractThe author provides context to the readers of the six papers featured in this issue of the Review of Central and East European Law, which examine elements of the new Civil Code of the Russian Federation from foreign and comparative law perspectives. A brief history of the milestones in Quebec and Russian experiences in private law codifi cation is supplemented with a narrative describing the lead role played in the latter by the Private Law Research Center in Moscow, and the support role played by, among others, the McGill University Faculty of Law.
The General Provisions on Contract in the Civil Code of the Russian Federation
Authors: Smith Stephen 
Published: April 2005

AbstractThe author offers a critical examination of the general provisions on contract in the Civil Code of the Russian Federation. Focusing narrowly on the text of the code, the paper starts with a broad overview of, and commentary on, the general provisions and their relation to other parts of the code, and then provides a detailed article-by-article commentary on individual provisions. Potential difficulties are identified and suggestions are offered for how the text might be clarified (and in particular simplified) or, in certaincases, substantively changed. The author contends that the general provisions provide for a legal framework that is appropriate in broad terms; however, individual articles in the provisions are not beyond criticism. The author makes clear that his criticisms and suggestions are largely at the level of fine-tuning, rather than first principle.
Randomized Phase III Study of Matrix Metalloproteinase Inhibitor BMS-275291 in Combination With Paclitaxel and Carboplatin in Advanced Non-Small-Cell Lung Cancer: National Cancer Institute of Canada-Clinical Trials Group Study BR.18
Authors: Leighl Natasha B. , Paz-Ares Luis , Douillard Jean-Yves , Peschel Christian , Arnold Andrew , Depierre Alain , Santoro Armando , Betticher Daniel C. , Gatzemeier Ulrich , Jassem Jacek , Crawford Jeffrey , Tu Dongsheng , Bezjak Andrea , Humphrey Jeffrey S. , Voi Maurizio , Galbraith Susan , Hann Katherine , Seymour Lesley , Shepherd Frances A. 
Published: April 2005

Purpose To determine whether BMS-275291, a broad-spectrum matrix metalloproteinase inhibitor (MMPI), added to systemic chemotherapy improved survival in advanced non–small-cell lung cancer (NSCLC). In early phase studies, BMS- 275291 was not associated with dose-limiting joint toxicity seen with other MMPIs. Patients and Methods Chemotherapy-naive patients with stage IIIB/IV NSCLC, performance status (PS) 0 to 2, and adequate organ function were eligible. All patients received paclitaxel 200 mg/m2 plus carboplatin (area under the curve, 6 mg/mL-min) intravenously every 21 days for up to 8 cycles, and were randomly assigned to receive BMS-275291, 1,200 mg orally daily, or placebo until disease progression. The primary study end point was survival (OS); secondary end points included progression-free survival (PFS), response rates (RR), toxicity, and quality of life. Results From 2000 to 2002, 774 patients were randomly assigned. Pretreatment characteristics were well balanced between arms: median age, 61 years; male sex, 73%; stage IV, 79%; PS 0 to 1, 88%. Interim safety analysis revealed no survival advantage and increased toxicity in the experimental arm, and study treatment was stopped. Median OS, PFS and RR in the final analysis in the BMS-275291 arm were 8.6 months, 4.9 months, and 25.8% respectively, and in the control arm 9.2 months, 5.3 months, 33.7%. Toxicity was significantly higher in the BMS-275291 arm, including flu-like symptoms, rash, hypersensitivity reactions (8.6% v 2.4%), and febrile neutropenia (9.7% v 5.5%). Conclusion BMS-275291 added to chemotherapy increases toxicity and does not improve survival in advanced NSCLC.
Doxorubicin With Cyclophosphamide Followed by Docetaxel Every 21 Days Compared With Doxorubicin and Docetaxel Every 14 Days As Preoperative Treatment in Operable Breast Cancer: The GEPARDUO Study of the German Breast Group
Authors: von Minckwitz Gunter , Raab Günter , Caputo Angelika , Schütte Martin , Hilfrich Jörn , Blohmer Jens U. , Gerber Bernd , Costa Serban D. , Merkle Elisabeth , Eidtmann Holger , Lampe Dieter , Jackisch Christian , du Bois Andreas , Kaufmann Manfred 
Published: April 2005

Purpose Dose-dense and sequential administration of cytotoxic drugs are current approaches to improve outcomes in patients with early-stage breast cancer. Methods This phase III study investigated 913 women with untreated operable breast cancer (T2-3, N0-2, M0) randomly assigned to receive either doxorubicin 50 mg/m2 plus docetaxel 75 mg/m2 every 14 days for four cycles with filgrastim support (ADOC), or doxorubicin 60 mg/m2 plus cyclophosphamide 600 mg/m2 every 21 days followed by docetaxel 100 mg/m2 every 21 days for four cycles each (AC-DOC). The primary end point was the incidence of pathologic complete (invasive and noninvasive) response (pCR) in the breast and axillary nodes. Secondary end points were predictors for pCR, clinical response, rate of breast conservation, and safety. Results A pCR was achieved in 94 patients (10.6%), but the likelihood was significantly greater with AC-DOC (14.3%; n = 63) than with ADOC (7.0%; n = 31) (odds ratio, 2.22; 90% CI, 1.52 to 3.24; P < .001). Independent predictors of attaining a pCR included the use of sequential therapy, high tumor grade, and negative hormone receptor status. The response rates detected by palpation and by imaging were significantly higher with AC-DOC (85.0% and 78.6%, respectively) than with ADOC (75.2% and 68.6%, respectively; both P values < .001). The rate of breast-conserving surgery was 63.4% for AC-DOC and 58.1% for ADOC (P = .05). Predominant grade 3/4 toxicities were leucopenia (AC-DOC, 74.2%; ADOC, 53.7%) and neutropenia (AC-DOC, 66.4%; ADOC, 44.7%) but were infrequently associated with fever (AC-DOC, 4.6%; ADOC, 3.1%). Conclusion Sequential AC-DOC is more effective at inducing pCR than dose-dense ADOC as preoperative treatment for patients with operable breast cancer.
Efficient and Concise Synthesis of βMan1–4GlcN Linkage of Pentasaccharide Core by Using 6-Nitro-2-benzothiazolyl α-Mannoside
Authors: Mandai Hiroki , Mukaiyama Teruaki 
Published: April 2005

Abstract
Efficient and concise synthesis of βMan1–4GlcN of pentasaccharide core is established; direct β-mannosylations of 4-OH group of 2-deoxy-2-phthaloyl and 2-azide-2-deoxy glucose derivatives by using 6-nitro-2-benzothiazolyl α-mannoside proceeded smoothly to afford the desired β-mannosides in high yields.
Performance Enhancement by Blending Merocyanine Photosensitizer in TiO2/Polythiophen Solid-state Solar Cells
Authors: Takahashi Kohshin , Nakanishi Takuya , Yamaguchi Takahiro , Nakamura Jun-ichi , Murata Kazuhiko 
Published: April 2005

Abstract
When the photosensitizing 3-ethyl-5-[3-ethyl-5-[2-(3-ethyl-2(3H)-benzothiazolylidene)ethylidene]-4-oxo-2-thiazolidinylidene]-2-thioxo-4-thiazolidinone (NK2097) was blended into the regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT), the performance of the TiO2/P3HT + NK2097 sandwich-type solar cell was remarkably improved, resulting in 0.85% of energy conversion yield under the illumination of simulated sunlight with 100 mW/cm2 intensity.
Adams–Oliver syndrome and hepatoportal sclerosis: Occasional association or common mechanism?
Authors: Girard Muriel , Amiel Jeanne , Fabre Monique , Pariente Danièle , Lyonnet Stanislas , Jacquemin Emmanuel 
Published: April 2005

AbstractAdams–Oliver syndrome (AOS) is characterized by the association of scalp and skull defects and abnormalities of terminal limbs. Congenital heart malformations have also been reported. Hepatoportal sclerosis (HPS) is a rare cause of portal hypertension in children characterized by abnormalities of intra‐hepatic portal veins, portal fibrosis, and nodular regeneration. Etiopathogenesis of these rare disorders remains unclear, but the hypothesis of vascular thrombotic mechanism has been suggested. Association of both syndromes has been reported in only one child. We now report on two unrelated children with AOS and HPS, one child harboring a factor V Leiden mutation. We hypothesize that the association of both disorders may not be fortuitous and reinforces the idea that AOS and HPS may share a vascular thrombotic mechanism. © 2005 Wiley‐Liss, Inc.
Polarized confocal Raman microspectroscopy studies of chain orientation on injected poly(propylene)/montmorillonite nanocomposites
Authors: García‐López D. , Merino J. C. , Gobernado‐Mitre I. , Pastor J. M. 
Published: April 2005

AbstractMolecular orientation along the depth of poly(propylene) (PP) and PP nanocomposite samples was analyzed by using confocal Raman microspectroscopy. The injection process led to a chain orientation that is higher on the surface of the samples. Residual stresses were relaxed through an annealing treatment, resulting in an increase of the molecular orientation along the injection direction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2377–2382, 2005
Synthesis of chemically modified chitosans with a higher fatty acid glycidyl and their adsorption abilities for anionic and cationic dyes
Authors: Shimizu Yoshiaki , Tanigawa Shinsuke , Saito Yoshihiro , Nakamura Takeo 
Published: April 2005

AbstractNovel chitosan‐based materials with a higher fatty acid glycidyl as the chemically modified agent were synthesized and the adsorption ability of the resulting polymers has been evaluated for typical anionic and cationic dyes. The successful modification was confirmed by the infrared spectroscopic measurements. As the degree of substitution was decreased, the adsorption ability of the chemically modified chitosans for anionic dyes at the higher dye concentration was increased, and the modified chitosans with a lower degree of substitution showed a higher adsorption ability than that of an activated carbon at the higher dye concentration. For cationic dyes, the chemically modified chitosan showed a good adsorption power, especially when the adsorption power was evaluated by the flow methods. The improved adsorption ability of a chemically modified chitosan material was also confirmed by comparing it with that of a crosslinked chitosan material. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2423–2428, 2005