bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of a Novel Gene,wosA, Regulating FlhDC Expression inProteus mirabilis
Authors: Hatt Janet K. , Rather Philip N. 
Published: January 2008

ABSTRACTIn this study, we describewosA, aProteus mirabilisgene identified by its ability to increase swarming motility when overexpressed. At various times during the swarming cycle, the increased expression ofwosAresulted in a 4- to 16-fold upregulation of the transcription offlhDC, encoding the master regulator of the flagellar cascade. In turn, the expression offlaA, encoding flagellin, was substantially increased inwosA-overexpressing strains. The overexpression ofwosAalso resulted in constitutive swarmer cell differentiation in liquid medium, a normally nonpermissive condition. However, inwosA-overexpressing strains, the onset of swarming was not altered. A nullwosAallele resulted in a slight decrease in swarming motility. The expression ofwosAwas growth phase dependent during growth in liquid and on agar plates during swarmer cell differentiation. Increasing the viscosity of liquid medium by the addition of polyvinylpyrrolidone induced swarmer cell differentiation and resulted in a fourfold increase inwosAtranscription. AfliLmutation that results in constitutive swarmer cell elongation also increasedwosAtranscription. In this study, we discuss the possible role of thewosAgene product in signal transduction from solid surfaces to induce swarmer cell differentiation, possibly via alterations in the motor switch complex. This study also suggests that despite constitutive swarmer cell differentiation inwosA-overexpressing strains, there are additional regulatory and/or environmental conditions that may control the onset of swarming migration.
Maintenance Forced by a Restriction-Modification System Can Be Modulated by a Region in Its Modification Enzyme Not Essential for Methyltransferase Activity
Authors: Ohno Satona , Handa Naofumi , Watanabe-Matsui Miki , Takahashi Noriko , Kobayashi Ichizo 
Published: January 2008

ABSTRACT
Several type II restriction-modification gene complexes can force their maintenance on their host bacteria by killing cells that have lost them in a process called postsegregational killing or genetic addiction. It is likely to proceed by dilution of the modification enzyme molecule during rounds of cell division following the gene loss, which exposes unmethylated recognition sites on the newly replicated chromosomes to lethal attack by the remaining restriction enzyme molecules. This process is in apparent contrast to the process of the classical types of postsegregational killing systems, in which built-in metabolic instability of the antitoxin allows release of the toxin for lethal action after the gene loss. In the present study, we characterize a mutant form of the EcoRII gene complex that shows stronger capacity in such maintenance. This phenotype is conferred by an L80P amino acid substitution (T239C nucleotide substitution) mutation in the modification enzyme. This mutant enzyme showed decreased DNA methyltransferase activity at a higher temperature in vivo and in vitro than the nonmutated enzyme, although a deletion mutant lacking the N-terminal 83 amino acids did not lose activity at either of the temperatures tested. Under a condition of inhibited protein synthesis, the activity of the L80P mutant was completely lost at a high temperature. In parallel, the L80P mutant protein disappeared more rapidly than the wild-type protein. These results demonstrate that the capability of a restriction-modification system in forcing maintenance on its host can be modulated by a region of its antitoxin, the modification enzyme, as in the classical postsegregational killing systems.
Genome of the Actinomycete Plant Pathogen
Clavibacter michiganensis
subsp.
sepedonicus
Suggests Recent Niche Adaptation
Authors: Bentley Stephen D. , Corton Craig , Brown Susan E. , Barron Andrew , Clark Louise , Doggett Jon , Harris Barbara , Ormond Doug , Quail Michael A. , May Georgiana , Francis David , Knudson Dennis , Parkhill Julian , Ishimaru Carol A. 
Published: January 2008

ABSTRACT

Clavibacter michiganensis
subsp.
sepedonicus
is a plant-pathogenic bacterium and the causative agent of bacterial ring rot, a devastating agricultural disease under strict quarantine control and zero tolerance in the seed potato industry. This organism appears to be largely restricted to an endophytic lifestyle, proliferating within plant tissues and unable to persist in the absence of plant material. Analysis of the genome sequence of
C. michiganensis
subsp.
sepedonicus
and comparison with the genome sequences of related plant pathogens revealed a dramatic recent evolutionary history. The genome contains 106 insertion sequence elements, which appear to have been active in extensive rearrangement of the chromosome compared to that of
Clavibacter michiganensis
subsp.
michiganensis
. There are 110 pseudogenes with overrepresentation in functions associated with carbohydrate metabolism, transcriptional regulation, and pathogenicity. Genome comparisons also indicated that there is substantial gene content diversity within the species, probably due to differential gene acquisition and loss. These genomic features and evolutionary dating suggest that there was recent adaptation for life in a restricted niche where nutrient diversity and perhaps competition are low, correlated with a reduced ability to exploit previously occupied complex niches outside the plant. Toleration of factors such as multiplication and integration of insertion sequence elements, genome rearrangements, and functional disruption of many genes and operons seems to indicate that there has been general relaxation of selective pressure on a large proportion of the genome.
Critical Role of a Single Position in the −35 Element for Promoter Recognition by
Mycobacterium tuberculosis
SigE and SigH
Authors: Song Taeksun , Song Seung-Eun , Raman Sahadevan , Anaya Mauricio , Husson Robert N. 
Published: January 2008

ABSTRACT

Mycobacterial SigE and SigH both initiate transcription from the
sigB
promoter, suggesting that they recognize similar sequences. Through mutational and primer extension analyses, we determined that SigE and SigH recognize nearly identical promoters, with differences at the 3′ end of the −35 element distinguishing between SigE- and SigH-dependent promoters.
The C-Terminal Extension of Ferrochelatase Is Critical for Enzyme Activity and for Functioning of the Tetrapyrrole Pathway in
Synechocystis
Strain PCC 6803
Authors: Sobotka Roman , McLean Samantha , Zuberova Monika , Hunter C. Neil , Tichy Martin 
Published: January 2008

ABSTRACT

Heme and chlorophyll (Chl) share a common biosynthetic pathway up to the branch point where magnesium chelatase and ferrochelatase (FeCH) insert either magnesium for Chl biosynthesis or ferrous iron for heme biosynthesis. A distinctive feature of FeCHs in cyanobacteria is their C-terminal extension, which forms a putative transmembrane segment containing a Chl-binding motif. We analyzed the ΔH324 strain of
Synechocystis
sp. strain PCC 6803, which contains a truncated FeCH enzyme lacking this C-terminal domain. Truncated FeCH was localized to the membrane fraction, suggesting that the C-terminal domain is not necessary for membrane association of the enzyme. Measurements of enzyme activity and complementation experiments revealed that the ΔH324 mutation dramatically reduced activity of the FeCH, which resulted in highly upregulated 5-aminolevulinic acid synthesis in the ΔH324 mutant, implying a direct role for heme in the regulation of flux through the pathway. Moreover, the ΔH324 mutant accumulated a large amount of protoporphyrin IX, and levels of Chl precursors were also significantly increased, suggesting that some, but not all, of the “extra” flux can be diverted down the Chl branch. Analysis of the recombinant full-length and truncated FeCHs demonstrated that the C-terminal extension is critical for activity of the FeCH and that it is strictly required for oligomerization of this enzyme. The observed changes in tetrapyrrole trafficking and the role of the C terminus in the functioning of FeCH are discussed.
Structural and Functional Characterization of an Organic Hydroperoxide Resistance Protein from
Mycoplasma gallisepticum
Authors: Jenkins Cheryl , Samudrala Ram , Geary Steven J. , Djordjevic Steven P. 
Published: January 2008

ABSTRACT

As obligate parasites,
Mycoplasma
species are continuously exposed to oxidative damage due to host-generated peroxides and reactive oxygen species (ROS). In addition, the production of endogenous oxidants is believed to be a primary virulence mechanism of several Mollicute species, indicating that oxidative stress resistance is crucial to survival of these bacteria in the host milieu. Despite the abundance of oxidants at the site of infection, enzymes responsible for the detoxification of ROS have never been characterized in mycoplasmas. Here we characterize a homolog of the
ohr
(organic hydroperoxide resistance) family from
Mycoplasma gallisepticum
(encoding MGA1142). Unlike previously characterized
ohr
genes, the
mga1142
gene is not upregulated in response to oxidative stress but displays a novel pattern of expression. Both organic and inorganic peroxides can act as substrates for MGA1142, but they are degraded with various efficiencies. Furthermore, cumene hydroperoxide, an aromatic peroxide metabolized with high efficiency by other Ohr proteins, was shown to rapidly inactivate MGA1142, accounting for the sensitivity of
M. gallisepticum
cells to this compound. Comparative modeling of the MGA1142 quaternary structure revealed that the active site of this molecule has a relatively wide conformation. These data indicate that the natural substrate for MGA1142 differs from that for previously characterized Ohr proteins. Triton X-114 partitioning demonstrated that MGA1142 is located in both cytosol and membrane fractions, suggesting that in vivo this molecule plays a role in the detoxification of both endogenous and exogenous peroxides. A model describing how MGA1142 is likely to be oriented in the cell membrane is presented.
The Rcs Phosphorelay Is a Cell Envelope Stress Response Activated by Peptidoglycan Stress and Contributes to Intrinsic Antibiotic Resistance
Authors: Laubacher Mary E. , Ades Sarah E. 
Published: January 2008

ABSTRACTGram-negative bacteria possess stress responses to maintain the integrity of the cell envelope. Stress sensors monitor outer membrane permeability, envelope protein folding, and energization of the inner membrane. The systems used by gram-negative bacteria to sense and combat stress resulting from disruption of the peptidoglycan layer are not well characterized. The peptidoglycan layer is a single molecule that completely surrounds the cell and ensures its structural integrity. During cell growth, new peptidoglycan subunits are incorporated into the peptidoglycan layer by a series of enzymes called the penicillin-binding proteins (PBPs). To explore how gram-negative bacteria respond to peptidoglycan stress, global gene expression analysis was used to identifyEscherichia colistress responses activated following inhibition of specific PBPs by the β-lactam antibiotics amdinocillin (mecillinam) and cefsulodin. Inhibition of PBPs with different roles in peptidoglycan synthesis has different consequences for cell morphology and viability, suggesting that not all perturbations to the peptidoglycan layer generate equivalent stresses. We demonstrate that inhibition of different PBPs resulted in both shared and unique stress responses. The regulation of capsular synthesis (Rcs) phosphorelay was activated by inhibition of all PBPs tested. Furthermore, we show that activation of the Rcs phosphorelay increased survival in the presence of these antibiotics, independently of capsule synthesis. Both activation of the phosphorelay and survival required signal transduction via the outer membrane lipoprotein RcsF and the response regulator RcsB. We propose that the Rcs pathway responds to peptidoglycan damage and contributes to the intrinsic resistance ofE. colito β-lactam antibiotics.
Polarity in Archaeal Operon Transcription in
Thermococcus kodakaraensis
Authors: Santangelo Thomas J. , Čuboňová L'ubomíra , Matsumi Rie , Atomi Haruyuki , Imanaka Tadayuki , Reeve John N. 
Published: January 2008

ABSTRACT

An in vivo archaeal gene reporter system has been established based on TK1761, a gene that encodes a nonessential β-glycosidase in
Thermococcus kodakaraensis
. Following the introduction of nonsense codons into promoter-proximal genes, polarity in operon expression in this archaeon has been established by both microarray hybridization assays and a reporter gene expression system.
Review of Treatment and Complications in 79 Children With Rattlesnake Bite
Authors: Sotelo Norberto 
Published: January 2008

Introduction Envenomation by snakebite is a health problem in Mexico. Objective To review the treatment and complications of rattlesnake bites in 79 children. Materials and methods The variables studied were age, sex, season, hour, signs, symptoms, and complications during 1977 to 1996 (group I) and 1997 to 2006 (group II). Hospitalization time and antivenom type, including polyvalent equine antiviperin serum and a [F(ab′)2] antivenom (fabotherapic), were also studied. Results. Most incidents (35%) occurred within the perimeter of children's homes and 8.8% took place inside homes; 40.5% of the children were females; and most snakebites occurred during the summer (70.8%). Members of groups I and II received polyvalent equine antiviperin serum and fabotherapy, respectively. Hospitalization time was less in group II members ( P < .0001). The complications in group I members included hypoprothrombinemia and hypofibrinogenemia ( P < .0001). Conclusions Hospitalization time, complications, and treatment cost were less in patients undergoing fabotherapy.
A Histological and Ultrastructural Evaluation of the Patellar Tendon 10 Years after Reharvesting its Central Third
Authors: Lidén Mattias , Movin Tomas , Ejerhed Lars , Papadogiannakis Nikos , Blomén Eva , Hultenby Kjell , Kartus Jüri 
Published: January 2008

Purpose This study was undertaken to evaluate the histologic and ultrastructural characteristics of the patellar tendon 10 years after reharvesting its central third. Hypothesis In the long term, after its central third is reharvested, the patellar tendon does not regain a normal histological and ultrastructural appearance. Study Design Case-control study; Level of evidence, 3. Methods Twelve consecutive patients (4 women, 8 men) who underwent anterior cruciate ligament revision surgery using reharvested ipsilateral patellar tendon autografts were included in the study. Percutaneous biopsy samples were obtained from the central and lateral parts of the patellar tendon under ultrasonographic guidance at a median of 116 months (range, 102–127 months) after the revision procedure. Eleven biopsy specimens from asymptomatic patellar tendons obtained from open anterior cruciate ligament reconstructions served as controls. The histologic characteristics and the presence of glycosaminoglycans were assessed using a light microscope, and the ultrastructure was assessed using a transmission electron microscope. Results The histological evaluation revealed deterioration in fiber structure, increased cellularity, and increased vascularity in both the central and peripheral parts of the reharvested patellar tendon specimens compared with normal tendon specimens. No difference in the amount of glycosaminoglycans was seen in specimens from either part of the reharvested patellar tendons and the control specimens. The ultrastructural evaluation revealed that all the control specimens had a normal morphologic appearance and a compact extracellular matrix with regularly oriented collagen fibrils. Furthermore, in the control specimens, the fibril diameter was heterogeneous, with all fibril size classes present. Specimens from the central and the lateral part of the reharvested tendon displayed pathological cell appearance and a more heterogeneous extracellular matrix. The lateral specimens from the reharvested tendons also displayed all fibril size classes but with a more homogeneous distribution. In the central specimens, the largest fibril size class was absent. Conclusion Ten years after its central third was reharvested for anterior cruciate ligament revision surgery, the patellar tendon had not normalized in terms of its histological and ultrastructural appearance.
Absorption of Dexamethasone Sodium Phosphate in Human Connective Tissue Using Iontophoresis
Authors: Gurney A. Burke , Wascher Daniel C. 
Published: January 2008

Background Iontophoresis ostensibly facilitates the delivery of medications through the skin to underlying tissues using a direct electrical current. Dexamethasone is the most commonly used medication with iontophoresis to treat a variety of connective tissue disorders. Hypothesis Iontophoresis will facilitate the absorption of dexamethasone into connective tissue compared with diffusion. Study Design Controlled laboratory study. Methods Twenty-nine adults undergoing anterior cruciate ligament reconstructive surgery using the semitendinosus/gracilis autograft were randomly assigned to either a true iontophoresis (TI) or sham iontophoresis (SI). In the TI group, a 40-mA/min dose of iontophoresis using a 0.4% (4 mg/mL) solution of dexamethasone was used targeting the semitendinosus tendon just before surgery. The SI group underwent the same treatment, but the machine was not turned on. Tissue was extracted within 4 hours of treatment and analyzed for dexamethasone. In addition, 2 control samples were sent to the laboratory for analysis. Results There was a statistically significant difference in dexamethasone concentrations between the groups ( P = .0216). Of the 16 samples in the TI group, 8 had measurable amounts of dexamethasone, with an average concentration of 2.906 ng/g of tendon tissue. In the SI group, 1 of the 13 samples had measurable amounts of dexamethasone with an average concentration of 0.205 ng/g of tendon tissue. The control samples contained no dexamethasone. Conclusion Iontophoresis facilitates the transmission of dexamethasone to connective tissues in humans. Clinical Relevance Iontophoresis can deliver dexamethasone to connective tissues in humans.
Pivotal Advance: Eosinophils mediate early alum adjuvant-elicited B cell priming and IgM production
Authors: Wang Hai-Bin , Weller Peter F 
Published: January 2008

AbstractAlum, aluminum-hydroxide-containing compounds, long used as adjuvants in human vaccinations, functions by ill-defined, immunostimulatory mechanisms. Antigen-free alum has been shown to act via a previously unidentified, splenic Gr1+, IL-4-expressing myeloid cell population to stimulate early B cell priming. We demonstrate that the alum-elicited and -activated splenic myeloid cells are IL-4-expressing eosinophils that function to prime B cell responses. Eosinophils are the principal Gr1+, IL-4+ cells in the spleens 6 days following i.p. alum administration. Alum-elicited splenic B cell priming, as evidenced by MHC II cross-linking-mediated calcium mobilization developed in wild-type BALB/c mice, was absent in ΔdblGATA BALB/c eosinophil-deficient mice and could be reconstituted by adoptive eosinophil infusions into the eosinophil-deficient mice. Moreover, early antigen-specific IgM antibody responses in alum-antigen-immunized mice were impaired in eosinophil-deficient mice and were restored with adoptive transfers of eosinophils. Thus, eosinophils, leukocytes of the innate immune system that contain preformed cytokines, including IL-4, have novel, immunomodulatory roles in the initial priming of B cells elicited by the adjuvant alum and in the optimal early B cell generation of antigen-specific IgM.
Extemporaneous product use in paediatric patients: a systematic review
Authors: Giam Jennifer A , McLachlan Andrew J 
Published: January 2008

Abstract

Objective
To identify the relative extent of extemporaneous product use reported in the paediatric population and the implications for pharmacy practice.

Method
A systematic literature review was undertaken to identify the prevalence of extemporaneous product use in paediatric patients including those studies examining both ‘off-label’ and unlicensed medicine use from which extemporaneous products were separately identified and compared to licensed drug use.

Key findings
Twenty studies were identified and evaluated in which extemporaneous products prepared by a pharmacy or licensed manufacturer could be identified. Although prescribing of unlicensed drugs and licensed drugs used ‘off-label’ occurs more frequently in younger children and for more serious conditions, the use of extemporaneous products is consistent across all age groups and therapeutic areas. Studies using pharmacy dispensing records identified details of extemporaneous products more accurately than studies using prescribing records. Despite efforts to improve the availability of suitable licensed medicine products for children, extemporaneously prepared products are still needed to ensure that optimal drug therapy is available to children in accurate and effective doses and dosage forms.

Conclusions
Paediatric patients have a continuing need for extemporaneously prepared medicines when suitable dose forms are unavailable from manufacturers. Pharmacists require access to stability, compatibility and formulation information, as well as appropriate training to ensure patients are supplied with high-quality, safe and effective preparations.
Reclassification of omeprazole: a survey of community pharmacists' early experiences and views
Authors: McCaig D , Hansford D , John D N , Cunningham S , Stewart D 
Published: January 2008

Abstract

Objective
To describe community pharmacists' views and early experiences of over-the-counter (OTC) omeprazole.

Method
A cross-sectional pre-piloted postal questionnaire was sent to 2000 randomly selected community pharmacy premises in Great Britain (approximately 15%). The questionnaire comprised items on: attitudes to OTC omeprazole; continuing education; sales; and general views and experiences. Two reminders were sent. Data were analysed using descriptive statistics.

Results
Questionnaires were returned by 1156 community pharmacists (57.8%). Sixty-eight per cent of respondents had not sold any omeprazole in the previous 14 days and a further 12% had sold only a single pack in this period. In total 920/1147 pharmacists (80.2%) had participated in continuing education on omeprazole, 73.4% agreed or strongly agreed that they were entirely confident in selling it, and 78.0% viewed omeprazole as a welcome addition to OTC medicines. Some 17.6% of respondents had recommended purchase of omeprazole in the last 14 days and the vast majority of these recommendations (92.8%) were accepted by the customer. Forty-one pharmacists (3.5%) had refused sales on the basis that it was inappropriate for the presenting condition, or due to a potential drug interaction.

Conclusion
Many responding community pharmacists welcome omeprazole availability OTC and are willing and able to supply it.