bluuebunny/crossref_metadata_2025_split huggingface dataset:
The energetic cost of activation in mouse fast‐twitch muscle is the same whether measured using reduced filament overlap or N‐benzyl‐p‐toluenesulphonamide
Authors: Barclay C. J. , Lichtwark G. A. , Curtin N. A. 
Published: March 2008

AbstractAim:  Force generation and transmembrane ion pumping account for the majority of energy expended by contracting skeletal muscles. Energy turnover for ion pumping, activation energy turnover (EA), can be determined by measuring the energy turnover when force generation has been inhibited. Most measurements show that activation accounts for 25–40% of isometric energy turnover. It was recently reported that when force generation in mouse fast‐twitch muscle was inhibited using N‐benzyl‐p‐toluenesulphonamide (BTS), activation accounted for as much as 80% of total energy turnover during submaximal contractions. The purpose of this study was to compare EA measured by inhibiting force generation by: (1) the conventional method of reducing contractile filament overlap; and (2) pharmacological inhibition using BTS.Methods:  Experiments were performed in vitro using bundles of fibres from mouse fast‐twitch extensor digitorum longus (EDL) muscle. Energy turnover was quantified by measuring the heat produced during 1‐s maximal and submaximal tetanic contractions at 20 and 30 °C.Results:  E
A measured using reduced filament overlap was 0.36 ± 0.04 (n = 8) at 20 °C and 0.31 ± 0.05 (n = 6) at 30 °C. The corresponding values measured using BTS in maximal contractions were 0.46 ± 0.06 and 0.38 ± 0.06 (n = 6 in both cases). There were no significant differences among these values. EA was also no different when measured using BTS in submaximal contractions.Conclusion:  Activation energy turnover is the same whether measured using BTS or reduced filament overlap and accounts for slightly more than one‐third of isometric energy turnover in mouse EDL muscle.
Exercise‐induced regulation of phospholemman (FXYD1) in rat skeletal muscle: implications for Na+/K+‐ATPase activity
Authors: Rasmussen M. K. , Kristensen M. , Juel C. 
Published: March 2008

AbstractBackground:  Na+/K+‐ATPase activity is upregulated during muscle exercise to maintain ionic homeostasis. One mechanism may involve movement of α‐subunits to the outer membrane (translocation).Aim:  We investigated the existence of exercise‐induced translocation and phosphorylation of phospholemman (PLM, FXYD1) protein in rat skeletal muscle and exercise‐induced changes in Vmax and Km for Na+ of the Na+/K+‐ATPase.Methods:  Two membrane fractionation methods and immunoprecipitation were used.Results:  Both fractionation methods revealed a 200–350% increase in PLM in the sarcolemma after 30 min of treadmill running, while the phosphorylation of Ser‐68 of PLM appeared to be unchanged. Exercise did not change Vmax or Km for Na+ of the Na+/K+‐ATPase in muscle homogenate, but induced a 67% increase in Vmax in the sarcolemmal giant vesicle preparation; Km for Na+ remained constant. The main part of the increase in Vmax is related to a 36–53% increase in the level of α‐subunits; the remainder may be related to increased PLM content. Similar results were obtained with another membrane purification method. In resting muscle, 29% and 32% of α1‐ and α2‐subunits, respectively, were co‐immunoprecipitated by PLM antibodies. In muscle homogenate prepared after exercise, immunoprecipitation of α1‐subunits was increased to 227%, whereas the fraction of precipitated α2 remained constant.Conclusion:  Exercise translocates PLM to the muscle outer membrane and increases its association with mainly the α1‐subunit, which may contribute to the increased Vmax of the Na+/K+‐ATPase.
Role of influenza and other respiratory viruses in admissions of adults to Canadian hospitals
Authors: Schanzer Dena L. , Langley Joanne M. , Tam Theresa W.S. 
Published: March 2008

Objective  We sought to estimate age‐specific hospitalization rates attributed to influenza and other virus for adults.Methods  Admissions from Canada’s national hospitalization database (Canadian Institute of Health Information), from 1994/95 to 1999/2000, were modeled as a function of proxy variables for influenza, respiratory syncytial virus (RSV) and other viral activity, seasonality and trend using a Poisson regression model and stratified by age group.Results  The average annual influenza‐attributed hospitalization rate for all adults, 20 years of age or older, over the study period, which included three severe seasons, was an estimated 65/100 000 population (95% CI 63–67). Among persons aged 65 and over, 270–340 admissions per 100 000 population per year were attributed to influenza, while 30–110, 60–90 and 130–350 per 100 000 were attributed to RSV, parainfluenza (PIV) and other respiratory viruses, respectively. Although marked season‐to‐season variation in age‐specific hospitalization rates attributable to influenza was observed in persons 50 years of age and older, increasing risk with age was preserved at all time periods.Conclusions  Influenza, RSV, PIV and other respiratory viruses were all associated with morbidity requiring hospitalization, while influenza was responsible for peak respiratory admissions. The burden of health care utilization associated with respiratory viruses is appreciable beginning in the sixth decade and increases significantly with age.
Sustainable flood risk management strategies to reduce rural communities' vulnerability to flooding in Mozambique
Authors: Lumbroso D. , Ramsbottom D. , Spaliveiro M. 
Published: March 2008

AbstractIn 2000, Mozambique was hit by widespread flooding that affected some 4.5 million people and cost approximately 20% of the country's gross domestic product. In a large, sparsely populated country such as Mozambique, a structural approach to flood risk management cannot be justified on environmental and economic grounds. As a consequence, flood mitigation measures need to focus on nonstructural solutions, such as reducing vulnerability to flooding and improving preparedness. This paper details the development of sustainable flood risk management strategies and the production of educational tools to reduce rural communities' vulnerability to flooding. The tools, which were developed in partnership with local stakeholders, included a Source Book on sustainable flood risk management strategies, a series of posters, a manual and a card game aimed at improving schoolchildren's flood preparedness. These tools were piloted in partnership with three rural communities in the Limpopo River basin in order to develop sustainable flood risk management strategies.
High Resistance to Oxidative Stress in the Fungal Pathogen
Candida glabrata
Is Mediated by a Single Catalase, Cta1p, and Is Controlled by the Transcription Factors Yap1p, Skn7p, Msn2p, and Msn4p
Authors: Cuéllar-Cruz Mayra , Briones-Martin-del-Campo Marcela , Cañas-Villamar Israel , Montalvo-Arredondo Javier , Riego-Ruiz Lina , Castaño Irene , De Las Peñas Alejandro 
Published: March 2008

ABSTRACT

We characterized the oxidative stress response of
Candida glabrata
to better understand the virulence of this fungal pathogen.
C. glabrata
could withstand higher concentrations of H
2
O
2
than
Saccharomyces cerevisiae
and even
Candida albicans
. Stationary-phase cells were extremely resistant to oxidative stress, and this resistance was dependent on the concerted roles of stress-related transcription factors Yap1p, Skn7p, and Msn4p. We showed that growing cells of
C. glabrata
were able to adapt to high levels of H
2
O
2
and that this adaptive response was dependent on Yap1p and Skn7p and partially on the general stress transcription factors Msn2p and Msn4p.
C. glabrata
has a single catalase gene,
CTA1
, which was absolutely required for resistance to H
2
O
2
in vitro. However, in a mouse model of systemic infection, a strain lacking
CTA1
showed no effect on virulence.
Identification of a Novel Mycobacterial 3-Hydroxyacyl-Thioester Dehydratase, HtdZ (Rv0130), by Functional Complementation in Yeast
Authors: Gurvitz Aner , Hiltunen J. Kalervo , Kastaniotis Alexander J. 
Published: March 2008

ABSTRACT

We report on the identification of
Mycobacterium tuberculosis
HtdZ (Rv0130), representing a novel 3-hydroxyacyl-thioester dehydratase. HtdZ was picked up by the functional complementation of
Saccharomyces cerevisiae htd2
Δ cells lacking the dehydratase of mitochondrial type II fatty acid synthase. Mutant cells expressing HtdZ contained dehydratase activity, recovered their respiratory ability, and partially restored de novo lipoic acid synthesis.
Dihydrolipoamide Dehydrogenase Mutation Alters the NADH Sensitivity of Pyruvate Dehydrogenase Complex of
Escherichia coli
K-12
Authors: Kim Youngnyun , Ingram L. O. , Shanmugam K. T. 
Published: March 2008

ABSTRACT

Under anaerobic growth conditions, an active pyruvate dehydrogenase (PDH) is expected to create a redox imbalance in wild-type
Escherichia coli
due to increased production of NADH (>2 NADH molecules/glucose molecule) that could lead to growth inhibition. However, the additional NADH produced by PDH can be used for conversion of acetyl coenzyme A into reduced fermentation products, like alcohols, during metabolic engineering of the bacterium.
E. coli
mutants that produced ethanol as the main fermentation product were recently isolated as derivatives of an
ldhA pflB
double mutant. In all six mutants tested, the mutation was in the
lpd
gene encoding dihydrolipoamide dehydrogenase (LPD), a component of PDH. Three of the LPD mutants carried an H322Y mutation (
lpd102
), while the other mutants carried an E354K mutation (
lpd101
). Genetic and physiological analysis revealed that the mutation in either allele supported anaerobic growth and homoethanol fermentation in an
ldhA pflB
double mutant. Enzyme kinetic studies revealed that the LPD(E354K) enzyme was significantly less sensitive to NADH inhibition than the native LPD. This reduced NADH sensitivity of the mutated LPD was translated into lower sensitivity of the appropriate PDH complex to NADH inhibition. The mutated forms of the PDH had a 10-fold-higher

K
i

for NADH than the native PDH. The lower sensitivity of PDH to NADH inhibition apparently increased PDH activity in anaerobic
E. coli
cultures and created the new ethanologenic fermentation pathway in this bacterium. Analogous mutations in the LPD of other bacteria may also significantly influence the growth and physiology of the organisms in a similar fashion.
Defining the Growth Conditions and Promoter-Proximal DNA Sequences Required for Activation of Gene Expression by CreBC in
Escherichia coli
Authors: Cariss S. James L. , Tayler Amy E. , Avison Matthew B. 
Published: March 2008

ABSTRACT

CreBC is a two-component system that controls the expression of a number of genes in
Escherichia coli
(called the cre regulon) that encode diverse functions, including intermediary metabolic enzymes. Using a reporter construct, we have shown that cre regulon gene expression is activated during growth in minimal media when glycolytic carbon sources are being fermented. It also is activated during aerobic growth when fermentation products are being used as carbon sources. CreB and CreC are essential for the activation of cre regulon gene expression, but CreA and CreD, encoded as part of the
creABCD
gene cluster, are not. CreB binds to a TTCACnnnnnnTTCAC direct repeat (the cre tag) in vitro, and this sequence, which is associated with cre regulon gene promoters, is required for the control of gene expression in vivo. These observations support the hypothesis that CreBC is a functional two-component system involved in the metabolic control of transcription in
E. coli
and confirm that CreB is a DNA binding transcriptional regulator.
A NovelStaphylococcus aureusBiofilm Phenotype Mediated by the Fibronectin-Binding Proteins, FnBPA and FnBPB
Authors: O'Neill Eoghan , Pozzi Clarissa , Houston Patrick , Humphreys Hilary , Robinson D. Ashley , Loughman Anthony , Foster Timothy J. , O'Gara James P. 
Published: March 2008

ABSTRACTDevice-associated infections involving biofilm remain a persistent clinical problem. We recently reported that four methicillin-resistantStaphylococcus aureus(MRSA) strains formed biofilm independently of theicaADBC-encoded exopolysaccharide. Here, we report that MRSA biofilm development was promoted under mildly acidic growth conditions triggered by the addition of glucose to the growth medium. Loss of sortase, which anchors LPXTG-containing proteins to peptidoglycan, reduced the MRSA biofilm phenotype. Furthermore introduction of mutations infnbAandfnbB, which encode the LPXTG-anchored multifunctional fibrinogen and fibronectin-binding proteins, FnBPA and FnBPB, reduced biofilm formation by several MRSA strains. However, these mutations had no effect on biofilm formation by methicillin-sensitiveS. aureusstrains. FnBP-promoted biofilm occurred at the level of intercellular accumulation and not primary attachment. Mutation offnbAorfnbBalone did not substantially affect biofilm, and expression of either gene alone from a complementing plasmid infnbA fnbBmutants restored biofilm formation. FnBP-promoted biofilm was dependent on the integrity of SarA but not through effects onfnbAorfnbBtranscription. Using plasmid constructs lacking regions of FnBPA to complement anfnbABmutant revealed that the A domain alone and not the domain required for fibronectin binding could promote biofilm. Additionally, an A-domain N304A substitution that abolished fibrinogen binding did not affect biofilm. These data identify a novelS. aureusbiofilm phenotype promoted by FnBPA and FnBPB which is apparently independent of the known ligand-binding activities of these multifunctional surface proteins.
Transcriptional Analysis and Functional Characterization of a Gene Pair Encoding Iron-Regulated Xenocin and Immunity Proteins of
Xenorhabdus nematophila
Authors: Singh Jitendra , Banerjee Nirupama 
Published: March 2008

ABSTRACT

We describe a two-gene cluster encoding a bacteriocin, xenocin, and the cognate immunity protein in the insect-pathogenic bacterium
Xenorhabdus nematophila
, which infects and kills larval stages of the common crop pest
Helicoverpa armigera
. The two genes,
xcinA
and
ximB
, are present in the genome as a single transcriptional unit, which is regulated under SOS conditions. The stress-inducible promoter was activated by mitomycin C, glucose, and Fe
3+
depletion and at an elevated temperature when it was tested in
Escherichia coli
cells. Expression of the xenocin protein alone in
E. coli
inhibited the growth of this organism. The growth inhibition was abolished when the immunity protein was also present. A recombinant xenocin-immunity protein complex inhibited the growth of
E. coli
indicator cells when it was added exogenously to a growing culture. Xenocin is an endoribonuclease with an enzymatically active C-terminal domain. Six resident bacterial species (i.e.,
Bacillus
,
Enterobacter
,
Enterococcus
,
Citrobacter
,
Serratia
, and
Stenotrophomonas
species) from the
H. armigera
gut exhibited sensitivity to recombinant xenocin when the organisms were grown under iron-depleted conditions and at a high temperature. Xenocin also inhibited the growth of two
Xenorhabdus
isolates. This study demonstrates that Fe
3+
depletion acts as a common cue for synthesis of xenocin by
X. nematophila
and sensitization of the target strains to the bacteriocin.
Cloning, Solubilization, and Characterization of Squalene Synthase from
Thermosynechococcus elongatus
BP-1
Authors: Lee Sungwon , Poulter C. Dale 
Published: March 2008

ABSTRACT

Squalene synthase (SQS) is a bifunctional enzyme that catalyzes the condensation of two molecules of farnesyl diphosphate (FPP) to give presqualene diphosphate (PSPP) and the subsequent rearrangement of PSPP to squalene. These reactions constitute the first pathway-specific steps in hopane biosynthesis in
Bacteria
and sterol biosynthesis in
Eukarya
. The genes encoding SQS were isolated from the hopane-producing bacteria
Thermosynechococcus elongatus
BP-1,
Bradyrhizobium japonicum
, and
Zymomonas mobilis
and cloned into an
Escherichia coli
expression system. The expressed proteins with a His
6
tag were found exclusively in inclusion bodies when no additives were used in the buffer. After extensive optimization, soluble recombinant
T. elongatus
BP-1 SQS was obtained when cells were disrupted and purified in buffers containing glycerol. The recombinant
B. japonicum
and
Z. mobilis
SQSs could not be solubilized under any of the expression and purification conditions used. Purified
T. elongatus
His
6
-SQS gave a single band at 42 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and molecular ion at
m/z
41886 by electrospray mass spectrometry. Incubation with FPP and NADPH gave squalene as the sole product. Incubation of the enzyme with [
14
C]FPP in the absence of NADPH gave PSPP. The enzyme requires Mg
2+
for activity, has an optimum pH of 7.6, and is strongly stimulated by detergent. Under optimal conditions, the
K

m

of FPP is 0.97 ± 0.10 μM and the
k
cat
is 1.74 ± 0.04 s
−1
. Zaragozic acid A, a potent inhibitor of mammalian, fungal, and
Saccharomyces cerevisiae
SQSs, also inhibited recombinant
T. elongatus
BP-1 SQS, with a 50% inhibitory concentration of 95.5 ± 13.6 nM.
Complete Genome Sequence of Uropathogenic
Proteus mirabilis
, a Master of both Adherence and Motility
Authors: Pearson Melanie M. , Sebaihia Mohammed , Churcher Carol , Quail Michael A. , Seshasayee Aswin S. , Luscombe Nicholas M. , Abdellah Zahra , Arrosmith Claire , Atkin Becky , Chillingworth Tracey , Hauser Heidi , Jagels Kay , Moule Sharon , Mungall Karen , Norbertczak Halina , Rabbinowitsch Ester , Walker Danielle , Whithead Sally , Thomson Nicholas R. , Rather Philip N. , Parkhill Julian , Mobley Harry L. T. 
Published: March 2008

ABSTRACT

The gram-negative enteric bacterium
Proteus mirabilis
is a frequent cause of urinary tract infections in individuals with long-term indwelling catheters or with complicated urinary tracts (e.g., due to spinal cord injury or anatomic abnormality).
P. mirabilis
bacteriuria may lead to acute pyelonephritis, fever, and bacteremia. Most notoriously, this pathogen uses urease to catalyze the formation of kidney and bladder stones or to encrust or obstruct indwelling urinary catheters. Here we report the complete genome sequence of
P. mirabilis
HI4320, a representative strain cultured in our laboratory from the urine of a nursing home patient with a long-term (≥30 days) indwelling urinary catheter. The genome is 4.063 Mb long and has a G+C content of 38.88%. There is a single plasmid consisting of 36,289 nucleotides. Annotation of the genome identified 3,685 coding sequences and seven rRNA loci. Analysis of the sequence confirmed the presence of previously identified virulence determinants, as well as a contiguous 54-kb flagellar regulon and 17 types of fimbriae. Genes encoding a potential type III secretion system were identified on a low-G+C-content genomic island containing 24 intact genes that appear to encode all components necessary to assemble a type III secretion system needle complex. In addition, the
P. mirabilis
HI4320 genome possesses four tandem copies of the
zapE
metalloprotease gene, genes encoding six putative autotransporters, an extension of the
atf
fimbrial operon to six genes, including an
mrpJ
homolog, and genes encoding at least five iron uptake mechanisms, two potential type IV secretion systems, and 16 two-component regulators.
Ethical opinions and personal attitudes of young adults conceived by in vitro fertilisation
Authors: Siegel S , Dittrich R , Vollmann J 
Published: March 2008

Background:Today in vitro fertilisation (IVF) is a widespread and important technique of reproductive medicine. When the technique was first used, it was considered ethically controversial. This is the first study conducted of adult IVF-offspring in order to learn about their ethical opinions and personal attitudes towards this medical technology.Methods:We recruited the participants from the first cases of in vitro fertilisation in Germany at the Gynaecological Clinic of the University Hospital Erlangen. Our qualitative interview study consisted of in-depth, face-to-face interviews with 16 adults who had been conceived by IVF. Our data was analysed with methods of Grounded Theory.Results:For these adults, the most important factor influencing their personal attitudes towards IVF was the knowledge that they were deeply wanted children. The artificiality of their conception seemed irrelevant for their ethical opinion. All participants mentioned that it was important for them to be informed about the circumstances of their conception by their parents.Conclusions:IVF seems to be a medical technique which, although it affects intimate aspects of human existence, can be integrated into the lives of the affected persons without any great difficulties. The findings suggest that parents should inform their children about their fertilisation at an early age and as part of a process over time, not only on a single occasion. Physicians should advise IVF-parents accordingly.
Ethically problematic treatment decisions in different medical specialties
Authors: Saarni S I , Halila R , Palmu P , Vänskä J 
Published: March 2008

Background: Ethical dilemmas are an integral part of medicine. Whether physicians actually feel that they have made ethically problematic treatment decisions or choices in their work is largely unknown. Identifying physicians with ethical problems, and the types of problems and underlying factors, might benefit organisational and educational efforts to help physicians solve ethical dilemmas in a constructive way. We investigated how the frequency and types of ethically difficult treatment decisions vary by specialty.Method: A mail survey of all non-retired Finnish physicians (n = 17 172, response rate 75.6%) was conducted in 2004. Of those who had made any ethically problematic treatment decisions, the types of decisions and reasons given for these decisions were asked for. Factor analysis was used to investigate clustering of ethically problematic treatment decisions, and logistic regression to investigate the effect of specialty, adjusted for age and gender.Results: Psychiatrists experienced ethically problematic treatment decisions most frequently, followed by pulmonologists, internists and neurologists. Problems were reported least often by pathologists, laboratory physicians and ophthalmologists. Overtreatment was more common than undertreatment in most specialties, with the exception of psychiatrists who emphasised undertreatment and patient rights issues.Conclusion: Physicians of different specialties differ significantly regarding frequency and types of ethically problematic treatment decisions they have made. Psychiatrists differ from all other specialists in reporting more undertreatment and patient rights issues. Experiencing ethically problematic decisions might affect the quality of care and physician well-being in many ways. The findings could be useful for both under- and postgraduate ethics education.