bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring women’s views of breastfeeding: a focus group study within an area with high levels of socio‐economic deprivation
Authors: McFadden Alison , Toole Glenyce 
Published: June 2006

AbstractThere is ample evidence of the short‐ and long‐term health benefits of breastfeeding for mothers and infants, yet breastfeeding rates remain low in the UK, particularly in areas of high social deprivation. It is imperative that appropriate strategies are utilized to support more women to initiate and continue breastfeeding. This study used focus group methodology to explore women’s views in relation to breastfeeding. The study was conducted within an area with high levels of socio‐economic deprivation in the north‐east of England and aimed to identify local barriers to breastfeeding, influences on choice of infant‐feeding method and strategies which might improve breastfeeding rates. Focus group discussions were conducted with low‐income women, adolescent women and women from a minority ethnic group. The five key themes that emerged from the data were: society’s negative attitudes towards breastfeeding; the influence of family and friends and the experience on choice of method of infant feeding; lack of knowledge of some aspects of infant feeding; perceptions of professional support; and women’s positive and negative experiences of breastfeeding. Recommendations for promoting and supporting breastfeeding include improving facilities to breastfeed in public, enhancing the provision of information, addressing conflicting advice and poor professional practice and implementing support mechanisms. The findings and recommendations have been used to develop a breastfeeding strategy to meet local needs. This project was funded by the English Department of Health Infant Feeding Initiative.
Diet, physical inactivity and the prevalence of constipation throughout and after pregnancy
Authors: Derbyshire Emma , Davies Jill , Costarelli Vassiliki , Dettmar Peter 
Published: June 2006

AbstractFew studies appear to have investigated the prevalence of constipation for all three trimesters of the gestative period, or indeed after birth. Using a prospective 4‐ to 7‐day weighed food diary, International Physical Activity Questionnaire and 7‐day bowel habit diary, dietary factors, physical activity levels and bowel habit parameters were assessed and examined concurrently at weeks 13, 25, 35 of pregnancy and 6 weeks post‐partum. Ninety‐four primiparous pregnant women were initially recruited, and 72, 59, 62 and 55 completed the first, second, third trimester and post‐partum study stages, respectively. Key dietary factors and physical activity levels were compared between the constipated and non‐constipated groups from each of the three trimesters and after parturition. Compared with non‐constipated mothers‐to‐be, constipated participants consumed statistically significantly less water in the first trimester (P = 0.04), more food in the second trimester (P = 0.04), and less iron (P = 0.02) and food (P = 0.04) in the third trimester and after birth, respectively. No statistically significant differences were identified between light, moderate and vigorous physical activity levels when groups were compared. This study demonstrates that dietary factors may play a role in terms of preventing, or alleviating, bowel habit perturbations both throughout and after pregnancy. Further research is required to investigate the interrelationship between physical activity and constipation during and after pregnancy.
RcsF Is an Outer Membrane Lipoprotein Involved in the RcsCDB Phosphorelay Signaling Pathway in
Escherichia coli
Authors: Castanié-Cornet Marie-Pierre , Cam Kaymeuang , Jacq Annick 
Published: June 2006

ABSTRACT

The RcsCDB signal transduction system is an atypical His-Asp phosphorelay conserved in γ-proteobacteria. Besides the three proteins directly involved in the phosphorelay, two proteins modulate the activity of the system. One is RcsA, which can stimulate the activity of the response regulator RcsB independently of the phosphorelay to regulate a subset of RcsB targets. The other is RcsF, a putative outer membrane lipoprotein mediating the signaling to the sensor RcsC. How RcsF transduces the signal to RcsC is unknown. Although the molecular and physiological signals remain to be identified, the common feature among the reported Rcs-activating conditions is perturbation of the envelope. As an initial step to explore the RcsF-RcsC functional relationship, we demonstrate that RcsF is an outer membrane lipoprotein oriented towards the periplasm. We also report that a null mutation in
surA
, a gene required for correct folding of periplasmic proteins, activates the Rcs pathway through RcsF. In contrast, activation of this pathway by overproduction of the membrane chaperone-like protein DjlA does not require RcsF. Conversely, activation of the pathway by RcsF overproduction does not require DjlA either, indicating the existence of two independent signaling pathways toward RcsC.
Borrelia burgdorferiEbfC, a Novel, Chromosomally Encoded Protein, Binds Specific DNA Sequences Adjacent toerpLoci on the Spirochete's Resident cp32 Prophages
Authors: Babb Kelly , Bykowski Tomasz , Riley Sean P. , Miller M. Clarke , DeMoll Edward , Stevenson Brian 
Published: June 2006

ABSTRACTAll examined isolates of the Lyme disease spirochete,Borrelia burgdorferi, naturally maintain numerous variants of a prophage family as circular cp32 episomes. Each cp32 carries a locus encoding one or two different Erp outer membrane, surface-exposed lipoproteins. Many of the Erp proteins bind a host complement regulator, factor H, which is hypothesized to protect the spirochete from complement-mediated killing. We now describe the isolation and characterization of a novel, chromosomally encoded protein, EbfC, that binds specific DNA sequences located immediately 5′ of allerploci. This is one of the first site-specific DNA-binding proteins to be identified in any spirochete. The location of theebfCgene on theB. burgdorferichromosome suggests that the cp32 prophages have evolved to use this bacterial host protein for their own benefit and that EbfC probably plays additional roles in the bacterium. A wide range of other bacteria encode homologs of EbfC, none of which have been well characterized, so demonstration thatB. burgdorferiEbfC is a site-specific DNA-binding protein has broad implications across the eubacterial kingdom.
Crystal Structure of Neurotropism-Associated Variable Surface Protein 1 (Vsp1) of
Borrelia turicatae
Authors: Lawson Catherine L. , Yung Brian H. , Barbour Alan G. , Zückert Wolfram R. 
Published: June 2006

ABSTRACT

Vsp surface lipoproteins are serotype-defining antigens of relapsing fever spirochetes that undergo multiphasic antigenic variation to allow bacterial persistence in spite of an immune response. Two isogenic serotypes of
Borrelia turicatae
strain Oz1 differ in their Vsp sequences and in disease manifestations in infected mice: Vsp1 is associated with the selection of a neurological niche, while Vsp2 is associated with blood and skin infection. We report here crystal structures of the Vsp1 dimer at 2.7 and 2.2 Å. The structures confirm that relapsing fever Vsp proteins share a common helical fold with OspCs of Lyme disease-causing
Borrelia
. The fold features an inner stem formed by highly conserved N and C termini and an outer “dome” formed by the variable central residues. Both Vsp1 and OspC structures possess small water-filled cavities, or pockets, that are lined largely by variable residues and are thus highly variable in shape. These features appear to signify tolerance of the Vsp-OspC fold for imperfect packing of residues at its antigenic surface. Structural comparison of Vsp1 with a homology model for Vsp2 suggests that observed differences in disease manifestation may arise in part from distinct differences in electrostatic surface properties; additional predicted positively charged surface patches on Vsp2 compared to Vsp1 may be sufficient to explain the relative propensity of Vsp2 to bind to acidic glycosaminoglycans.
The Synchrony Phenotype Persists after Elimination of Multiple GATC Sites from the
dnaA
Promoter of
Escherichia coli
Authors: Wilkinson Terry G. , Kedar G. C. , Lee Chi , Guzmán Elena C. , Smith Douglas W. , Zyskind Judith W. 
Published: June 2006

ABSTRACT

To examine whether methylation of the GATC sites present in the
dnaA
promoter region is responsible for the strict temporal coordination of initiation events at
oriC
as measured by the synchrony of initiation, we introduced point mutations eliminating three (TGW1) and five (TGW2) of the six GATC sites present in the
dnaA
promoter region. All of the strains containing these mutations, including the one with five GATC sites eliminated, initiated chromosomal replication synchronously.
Whole-Genome Transcription Profiling Reveals Genes Up-Regulated by Growth on Fucose in the Human Gut Bacterium “Roseburia inulinivorans”
Authors: Scott Karen P. , Martin Jennifer C. , Campbell Gillian , Mayer Claus-Dieter , Flint Harry J. 
Published: June 2006

ABSTRACT“Roseburia inulinivorans” is an anaerobic polysaccharide-utilizing firmicute bacterium from the human colon that was identified as a producer of butyric acid during growth on glucose, starch, or inulin.R. inulinivoransA2-194 is also able to grow on the host-derived sugar fucose, following a lag period, producing propionate and propanol as additional fermentation products. A shotgun genomic microarray was constructed and used to investigate the switch in gene expression that is involved in changing from glucose to fucose utilization. This revealed a set of genes coding for fucose utilization, propanediol utilization, and the formation of propionate and propanol that are up-regulated during growth on fucose. These include homologues of genes that are implicated in polyhedral body formation inSalmonella enterica. Dehydration of the intermediate 1,2-propanediol involves an enzyme belonging to the new B12-independent glycerol dehydratase family, in contrast toS. enterica, which relies on a B12-dependent enzyme. A typical gram-positiveagr-type quorum-sensing system was also up-regulated inR. inulinivoransduring growth on fucose. Despite the lack of genome sequence information for this commensal bacterium, microarray analysis has provided a powerful tool for obtaining new information on its metabolic capabilities.
The
rcsA
Promoter of
Pantoea stewartii
subsp.
stewartii
Features a Low-Level Constitutive Promoter and an EsaR Quorum-Sensing-Regulated Promoter
Authors: Carlier Aurelien L. , von Bodman S. B. 
Published: June 2006

ABSTRACT

The upstream region of the
Pantoea stewartii rcsA
gene features two promoters, one for constitutive basal-level expression and a second autoregulated promoter for induced expression. The EsaR quorum-sensing repressor binds to a site centered between the two promoters, blocking transcription elongation from the regulated promoter under noninducing conditions.
Mutational Analysis of theBacillus subtilisRNA Polymerase α C-Terminal Domain Supports the Interference Model of Spx-Dependent Repression
Authors: Zhang Ying , Nakano Shunji , Choi Soon-Yong , Zuber Peter 
Published: June 2006

ABSTRACTThe Spx protein ofBacillus subtilisexerts both positive and negative transcriptional control in response to oxidative stress by interacting with the C-terminal domain of the RNA polymerase (RNAP) alpha subunit (αCTD). Thus, transcription of thesrfoperon at the onset of competence development, which requires the ComA response regulator of the ComPA signal transduction system, is repressed by Spx-αCTD interaction. Previous genetic and structural analyses have determined that an Spx-binding surface resides in and around the α1 region of αCTD. Alanine-scanning mutagenesis ofB. subtilisαCTD uncovered residue positions required for Spx function and ComA-dependentsrftranscriptional activation. Analysis ofsrf-lacZfusion expression, DNase I footprinting, and solid-phase promoter retention experiments indicate that Spx interferes with ComA-αCTD interaction and that residues Y263, C265, and K267 of the α1 region lie within overlapping ComA- and Spx-binding sites for αCTD interaction. Evidence is also presented that oxidized Spx, while enhancing interference of activator-RNAP interaction, is not essential for negative control.
The
cbiS
Gene of the Archaeon
Methanopyrus kandleri
AV19 Encodes a Bifunctional Enzyme with Adenosylcobinamide Amidohydrolase and α-Ribazole-Phosphate Phosphatase Activities
Authors: Woodson Jesse D. , Escalante-Semerena Jorge C. 
Published: June 2006

ABSTRACT

Here we report the initial biochemical characterization of the bifunctional α-ribazole-P (α-RP) phosphatase, adenosylcobinamide (AdoCbi) amidohydrolase CbiS enzyme from the hyperthermophilic methanogenic archaeon
Methanopyrus kandleri
AV19. The
cbiS
gene encodes a 39-kDa protein with two distinct segments, one of which is homologous to the AdoCbi amidohydrolase (CbiZ, EC 3.5.1.90) enzyme and the other of which is homologous to the recently discovered archaeal α-RP phosphatase (CobZ, EC 3.1.3.73) enzyme. CbiS function restored AdoCbi salvaging and α-RP phosphatase activity in strains of the bacterium
Salmonella enterica
where either step was blocked. The two halves of the
cbiS
genes retained their function in vivo when they were cloned separately. The CbiS enzyme was overproduced in
Escherichia coli
and was isolated to >95% homogeneity. High-performance liquid chromatography, UV-visible spectroscopy, and mass spectroscopy established α-ribazole and cobyric acid as the products of the phosphatase and amidohydrolase reactions, respectively. Reasons why the CbiZ and CobZ enzymes are fused in some archaea are discussed.
Transposon Mutations in the 5′ End ofglnD, the Gene for a Nitrogen Regulatory Sensor, That Suppress the Osmosensitive Phenotype Caused byotsBALesions inEscherichia coli
Authors: Tøndervik Anne , Torgersen Haakon R. , Botnmark Hans K. , Strøm Arne R. 
Published: June 2006

ABSTRACTGlnD ofEscherichia coliis a bifunctional signal-transducing enzyme (102.4 kDa) which uridylylates the allosteric regulatory protein PII and deuridylylates PII-UMP in response to growth with nitrogen excess or limitation, respectively. GlnD catalyzes these reactions in response to high or low levels of cytoplasmic glutamine, respectively, and indirectly directs the expression of nitrogen-regulated genes, e.g., theglnK-amtBoperon. We report that chromosomal mini-Tn10insertions situated after nucleotide number 997 or 1075 ofglnDpartially suppressed the osmosensitive phenotype of ΔotsBAorotsA::Tn10mutations (defective osmoregulatory trehalose synthesis). Strains carrying theseglnD::mini-Tn10mutations either completely repressed the expression oftrp::(glnKp-lacZ) or induced this reporter system to nearly 60% of the wild-typeglnDlevel in response to nitrogen availability, an essentially normal response. This was in contrast to the much-studiedglnD99::Tn10mutation, which carries its insertion in the 3′ end of the gene, causes a complete repression ofglnKp-lacZexpression under all growth conditions, and also confers leaky glutamine auxotrophy. When expressed from thePmpromoter in plasmid constructs, the presentglnDmutations produced proteins with an apparent mass of 39 or 42 kDa. These proteins were deduced to comprise 344 or 370 N-terminal residues, respectively, harboring the known nucleotidyltransferase domain of GlnD, plus a common C-terminal addition of 12 residues encoded by IS10. They lacked three other domains of GlnD. Apparently, the transferase domain by itself enabled the cells to catalyze the uridylylation reaction and direct nitrogen-regulated gene expression. Our data indicate that there exists a link between osmotic stress and the nitrogen response.
Role for Tandem Duplication and Lon Protease in AcrAB-TolC- Dependent Multiple Antibiotic Resistance (Mar) in an
Escherichia coli
Mutant without Mutations in
marRAB
or
acrRAB
Authors: Nicoloff Hervé , Perreten Vincent , McMurry Laura M. , Levy Stuart B. 
Published: June 2006

ABSTRACT

A spontaneous mutant (M113) of
Escherichia coli
AG100 with an unstable multiple antibiotic resistance (Mar) phenotype was isolated in the presence of tetracycline. Two mutations were found: an insertion in the promoter of
lon
(
lon3
::IS
186
) that occurred first and a subsequent large tandem duplication, dupIS
186
, bearing the genes
acrAB
and extending from the
lon3
::IS
186
to another IS
186
present 149 kb away from
lon
. The decreased amount of Lon protease increased the amount of MarA by stabilization of the basal quantities of MarA produced, which in turn increased the amount of multidrug effux pump AcrAB-TolC. However, in a mutant carrying only a
lon
mutation, the overproduced pump mediated little, if any, increased multidrug resistance, indicating that the Lon protease was required for the function of the pump. This requirement was only partial since resistance was mediated when amounts of AcrAB in a
lon
mutant were further increased by a second mutation. In M113, amplification of
acrAB
on the duplication led to increased amounts of AcrAB and multidrug resistance. Spontaneous gene duplication represents a new mechanism for mediating multidrug resistance in
E. coli
through AcrAB-TolC.
Glycosylation of b-Type Flagellin of
Pseudomonas aeruginosa
: Structural and Genetic Basis
Authors: Verma Amrisha , Schirm Michael , Arora Shiwani K. , Thibault P. , Logan Susan M. , Ramphal Reuben 
Published: June 2006

ABSTRACT

The flagellin of
Pseudomonas aeruginosa
can be classified into two major types—a-type or b-type—which can be distinguished on the basis of molecular weight and reactivity with type-specific antisera. Flagellin from the a-type strain PAK was shown to be glycosylated with a heterogeneous O-linked glycan attached to Thr189 and Ser260. Here we show that b-type flagellin from strain PAO1 is also posttranslationally modified with an excess mass of up to 700 Da, which cannot be explained through phosphorylation. Two serine residues at positions 191 and 195 were found to be modified. Each site had a deoxyhexose to which is linked a unique modification of 209 Da containing a phosphate moiety. In comparison to strain PAK, which has an extensive flagellar glycosylation island of 14 genes in its genome, the equivalent locus in PAO1 comprises of only four genes. PCR analysis and sequence information suggested that there are few or no polymorphisms among the islands of the b-type strains. Mutations were made in each of the genes, PA1088 to PA1091, and the flagellin from these isogenic mutants was examined by mass spectrometry to determine whether they were involved in posttranslational modification of the type-b flagellin. While mutation of PA1088, PA1089, and PA1090 genes altered the composition of the flagellin glycan, only unmodified flagellin was produced by the PA1091 mutant strain. There were no changes in motility or lipopolysaccharide banding in the mutants, implying a role that is limited to glycosylation.
Molecular Mechanism of Tryptophan-Dependent Transcriptional Regulation inChlamydia trachomatis
Authors: Akers Johnny C. , Tan Ming 
Published: June 2006

ABSTRACTTryptophan is an essential amino acid that is required for normal development inChlamydiaspecies, and tryptophan metabolism has been implicated in chlamydial persistence and tissue tropism. The ability to synthesize tryptophan is not universal among theChlamydiaceae, but species that have a predicted tryptophan biosynthetic pathway also encode an ortholog of TrpR, a regulator of tryptophan metabolism in many gram-negative bacteria. We show that inChlamydia trachomatisserovar D, TrpR regulates its own gene andtrpBandtrpA, the genes for the two subunits of tryptophan synthase. These three genes form an operon that is transcribed by the major form of chlamydial RNA polymerase. TrpR acts as a tryptophan-dependent aporepressor that binds specifically to operator sequences upstream of thetrpRBAoperon. We also found that TrpR repressed in vitro transcription oftrpRBAin a promoter-specific manner, and the level of repression was dependent upon the concentrations of TrpR and tryptophan. Our findings provide a mechanism for chlamydiae to sense changes in tryptophan levels and to respond by modulating expression of the tryptophan biosynthesis genes, and we present a unified model that shows howC. trachomatiscan combine transcriptional repression and attenuation to regulate intrachlamydial tryptophan levels. In the face of host defense mechanisms that limit tryptophan availability from the infected cell, the ability to maintain homeostatic control of intrachlamydial tryptophan levels is likely to play an important role in chlamydial pathogenesis.
Novel Genetic Polymorphisms That Further Delineate the Phylogeny of the
Mycobacterium tuberculosis
Complex
Authors: Huard Richard C. , Fabre Michel , de Haas Petra , Claudio Oliveira Lazzarini Luiz , van Soolingen Dick , Cousins Debby , Ho John L. 
Published: June 2006

ABSTRACT

In a previous report, we described a PCR protocol for the differentiation of the various species of the
Mycobacterium tuberculosis
complex (MTC) on the basis of genomic deletions (R. C. Huard, L. C. de Oliveira Lazzarini, W. R. Butler, D. van Soolingen, and J. L. Ho, J. Clin. Microbiol.
41:
1637-1650, 2003). That report also provided a broad cross-comparison of several previously identified, phylogenetically relevant, long-sequence and single-nucleotide polymorphisms (LSPs and SNPs, respectively). In the present companion report, we expand upon the previous work (i) by continuing the evaluation of known MTC phylogenetic markers in a larger collection of tubercle bacilli (
n
= 125), (ii) by evaluating additional recently reported MTC species-specific and interspecific polymorphisms, and (iii) by describing the identification and distribution of a number of novel LSPs and SNPs. Notably, new genomic deletions were found in various
Mycobacterium tuberculosis
strains, new species-specific SNPs were identified for “
Mycobacterium canettii
,”
Mycobacterium microti
, and
Mycobacterium pinnipedii
, and, for the first time, intraspecific single-nucleotide DNA differences were discovered for the dassie bacillus, the oryx bacillus, and the two
Mycobacterium africanum
subtype I variants. Surprisingly, coincident polymorphisms linked one
M. africanum
subtype I genotype with the dassie bacillus and
M. microti
with
M. pinnipedii
, thereby suggesting closer evolutionary ties within each pair of species than had been previously thought. Overall, the presented data add to the genetic definitions of several MTC organisms as well as fine-tune current models for the evolutionary history of the MTC.