bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a T5-Like Coliphage, SPC35, and Differential Development of Resistance to SPC35 in
Salmonella enterica
Serovar Typhimurium and
Escherichia coli
Authors: Kim Minsik , Ryu Sangryeol
Published: January 2011

The potential of bacteriophage as an alternative biocontrol agent has recently been revisited due to the widespread occurrence of antibiotic-resistant bacteria. We isolated a virulent bacteriophage, SPC35, that can infect both
Salmonella enterica
serovar Typhimurium and
Escherichia coli
. Morphological analysis by transmission electron microscopy and analysis of its 118,351-bp genome revealed that SPC35 is a T5 group phage belonging to the family
Siphoviridae
. BtuB, the outer membrane protein for vitamin B
12
uptake, was found to be a host receptor for SPC35. Interestingly, resistant mutants of both
E. coli
and
S.
Typhimurium developed faster than our expectation when the cultures were infected with SPC35. Investigation of the
btuB
gene revealed that it was disrupted by the IS
2
insertion sequence element in most of the resistant
E. coli
isolates. In contrast, we could not detect any
btuB
gene mutations in the resistant
S.
Typhimurium isolates; these isolates easily regained sensitivity to SPC35 in its absence, suggesting phase-variable phage resistance/sensitivity. These results indicate that a cocktail of phages that target different receptors on the pathogen should be more effective for successful biocontrol.
Integrative Expression System for Delivery of Antibody Fragments by Lactobacilli
Authors: Martín M. Cruz , Pant Neha , Ladero Victor , Günaydın Gökçe , Andersen Kasper Krogh , Álvarez Beatriz , Martínez Noelia , Alvarez Miguel A. , Hammarström Lennart , Marcotte Harold
Published: January 2011

A series of expression cassettes which mediate secretion or surface display of antibody fragments was stably integrated in the chromosome of
Lactobacillus paracasei
.
L. paracasei
producing surface-anchored variable domain of llama heavy chain (VHH) (ARP1) directed against rotavirus showed efficient binding to rotavirus and protection in the mouse model of rotavirus infection.
Functional Study of Genes Essential for Autogamy and Nuclear Reorganization in Paramecium
Authors: Nowak Jacek K. , Gromadka Robert , Juszczuk Marek , Jerka-Dziadosz Maria , Maliszewska Kamila , Mucchielli Marie-Hélène , Gout Jean-François , Arnaiz Olivier , Agier Nicolas , Tang Thomas , Aggerbeck Lawrence P. , Cohen Jean , Delacroix Hervé , Sperling Linda , Herbert Christopher J. , Zagulski Marek , Bétermier Mireille
Published: January 2011

Like all ciliates,
Paramecium tetraurelia
is a unicellular eukaryote that harbors two kinds of nuclei within its cytoplasm. At each sexual cycle, a new somatic macronucleus (MAC) develops from the germ line micronucleus (MIC) through a sequence of complex events, which includes meiosis, karyogamy, and assembly of the MAC genome from MIC sequences. The latter process involves developmentally programmed genome rearrangements controlled by noncoding RNAs and a specialized RNA interference machinery. We describe our first attempts to identify genes and biological processes that contribute to the progression of the sexual cycle. Given the high percentage of unknown genes annotated in the
P. tetraurelia
genome, we applied a global strategy to monitor gene expression profiles during autogamy, a self-fertilization process. We focused this pilot study on the genes carried by the largest somatic chromosome and designed dedicated DNA arrays covering 484 genes from this chromosome (1.2% of all genes annotated in the genome). Transcriptome analysis revealed four major patterns of gene expression, including two successive waves of gene induction. Functional analysis of 15 upregulated genes revealed four that are essential for vegetative growth, one of which is involved in the maintenance of MAC integrity and another in cell division or membrane trafficking. Two additional genes, encoding a MIC-specific protein and a putative RNA helicase localizing to the old and then to the new MAC, are specifically required during sexual processes. Our work provides a proof of principle that genes essential for meiosis and nuclear reorganization can be uncovered following genome-wide transcriptome analysis.
G
1
/S Transcription Factor Orthologues Swi4p and Swi6p Are Important but Not Essential for Cell Proliferation and Influence Hyphal Development in the Fungal Pathogen Candida albicans
Authors: Hussein Bahira , Huang Hao , Glory Amandeep , Osmani Amin , Kaminskyj Susan , Nantel Andre , Bachewich Catherine
Published: January 2011

The G
1
/S transition is a critical control point for cell proliferation and involves essential transcription complexes termed SBF and MBF in
Saccharomyces cerevisiae
or MBF in
Schizosaccharomyces pombe
. In the fungal pathogen
Candida albicans
, G
1
/S regulation is not clear. To gain more insight into the G
1
/S circuitry, we characterized Swi6p, Swi4p and Mbp1p, the closest orthologues of SBF (Swi6p and Swi4p) and MBF (Swi6p and Mbp1p) components in
S. cerevisiae
. The
mbp1
Δ/Δ cells showed minor growth defects, whereas
swi4
Δ/Δ and
swi6
Δ/Δ yeast cells dramatically increased in size, suggesting a G
1
phase delay.
G
ene
s
et
e
nrichment
a
nalysis (GSEA) of transcription profiles revealed that genes associated with G
1
/S phase were significantly enriched in cells lacking Swi4p and Swi6p. These expression patterns suggested that Swi4p and Swi6p have repressing as well as activating activity. Intriguingly,
swi4
Δ
/
Δ
swi6
Δ/Δ and
swi4
Δ
/
Δ
mbp1
Δ/Δ strains were viable, in contrast to the situation in
S. cerevisiae
, and showed pleiotropic phenotypes that included multibudded yeast, pseudohyphae, and intriguingly, true hyphae. Consistently, GSEA identified strong enrichment of genes that are normally modulated during
C. albicans
-host cell interactions. Since Swi4p and Swi6p influence G
1
phase progression and SBF binding sites are lacking in the
C. albicans
genome, these factors may contribute to MBF activity. Overall, the data suggest that the putative G
1
/S regulatory machinery of
C. albican
s contains novel features and underscore the existence of a relationship between G
1
phase and morphogenetic switching, including hyphal development, in the pathogen.
A Second Mitochondrial DNA Primase Is Essential for Cell Growth and Kinetoplast Minicircle DNA Replication in Trypanosoma brucei
Authors: Hines Jane C. , Ray Dan S.
Published: January 2011

The mitochondrial DNA of trypanosomes contains two types of circular DNAs, minicircles and maxicircles. Both minicircles and maxicircles replicate from specific replication origins by unidirectional theta-type intermediates. Initiation of the minicircle leading strand and also that of at least the first Okazaki fragment involve RNA priming. The
Trypanosoma brucei
genome encodes two mitochondrial DNA primases, PRI1 and PRI2, related to the primases of eukaryotic nucleocytoplasmic large DNA viruses. These primases are members of the archeoeukaryotic primase superfamily, and each of them contain an RNA recognition motif and a PriCT-2 motif. In
Leishmania
species, PRI2 proteins are approximately 61 to 66 kDa in size, whereas in
Trypanosoma
species, PRI2 proteins have additional long amino-terminal extensions. RNA interference (RNAi) of
T. brucei PRI2
resulted in the loss of kinetoplast DNA and accumulation of covalently closed free minicircles. Recombinant PRI2 lacking this extension (PRI2ΔNT) primes poly(dA) synthesis on a poly(dT) template in an ATP-dependent manner. Mutation of two conserved aspartate residues (PRI2ΔNTCS) resulted in loss of enzymatic activity but not loss of DNA binding. We propose that PRI2 is directly involved in initiating kinetoplast minicircle replication.
Genome Sequence of
Lactobacillus farciminis
KCTC 3681
Authors: Nam Seong-Hyeuk , Choi Sang-Haeng , Kang Aram , Kim Dong-Wook , Kim Ryong Nam , Kim Aeri , Kim Dae-Soo , Park Hong-Seog
Published: January 2011

Lactobacillus farciminis
is one of the most prevalent lactic acid bacterial species present during the manufacturing process of kimchi, the best-known traditional Korean dish. Here, we present the draft genome sequence of the type strain
Lactobacillus farciminis
KCTC 3681 (2,498,309 bp, with a G+C content of 36.4%), which consists of 5 scaffolds.
Draft Genome Sequence of a Dominant, Multidrug-Resistant
Neisseria gonorrhoeae
Strain, TCDC-NG08107, from a Sexual Group at High Risk of Acquiring Human Immunodeficiency Virus Infection and Syphilis
Authors: Chen Chun-Chen , Hsia Ko-Chiang , Huang Chung-Ter , Wong Wing-Wai , Yen Muh-Yong , Li Lan-Hui , Lin Kun-Yen , Chen Kuo-Wei , Li Shu-Ying
Published: January 2011

Neisseria gonorrhoeae
infection is the second major cause of sexually transmitted diseases worldwide. Development of resistance to multiple classes of antimicrobials in
N. gonorrhoeae
has compromised treatment and disease control. Herein, we report the availability of the draft genome sequence of a multidrug-resistant
N. gonorrhoeae
isolate, TCDC-NG08107, which spread in groups of men who have sex with men (MSM) in Taiwan.
Genome Sequence of
Paracoccus
sp. Strain TRP, a Chlorpyrifos Biodegrader
Authors: Li Kang , Wang Shenghui , Shi Yanhua , Qu Jie , Zhai Yi , Xu Lili , Xu Yongxue , Song Jinlong , Liu Lili , Rahman M. Anisur , Yan Yanchun
Published: January 2011

Paracoccus
sp. strain TRP, isolated from activated sludge, could completely biodegrade chlorpyrifos and 3,5,6-trichloro-2-pyridinol. Here we report the draft genome sequence of
Paracoccus
sp. strain TRP, which could be used to predict genes for xenobiotic biodegradation and metabolism.
A Selenium-Dependent Xanthine Dehydrogenase Triggers Biofilm Proliferation inEnterococcus faecalisthrough Oxidant Production
Authors: Srivastava Milan , Mallard Chris , Barke Theresa , Hancock Lynn E. , Self William T.
Published: January 2011

Selenium has been shown to be present as a labile cofactor in a small class of molybdenum hydroxylase enzymes in several species of clostridia that specialize in the fermentation of purines and pyrimidines. This labile cofactor is poorly understood, yet recent bioinformatic studies have suggested thatEnterococcus faecaliscould serve as a model system to better understand the way in which this enzyme cofactor is built and the role of these metalloenzymes in the physiology of the organism. An mRNA that encodes a predicted selenium-dependent molybdenum hydroxylase (SDMH) has also been shown to be specifically increased during the transition from planktonic growth to biofilm growth. Based on these studies, we examined whether this organism produces an SDMH and probed whether selenoproteins may play a role in biofilm physiology. We observed a substantial increase in biofilm density upon the addition of uric acid to cells grown in a defined culture medium, but only when molybdate (Mo) and selenite (Se) were also added. We also observed a significant increase in biofilm density in cells cultured in tryptic soy broth with 1% glucose (TSBG) when selenite was added. In-frame deletion ofselD, which encodes selenophosphate synthetase, also blocked biofilm formation that occurred upon addition of selenium. Moreover, mutation in the gene encoding the molybdoenzyme (xdh) prevented the induction of biofilm proliferation upon supplementation with selenium. Tungstate or auranofin addition also blocked this enhanced biofilm density, likely through inhibition of molybdenum or selenium cofactor synthesis. A large protein complex labeled with75Se is present in higher concentrations in biofilms than in planktonic cells, and the same complex is formed in TSBG. Xanthine dehydrogenase activity correlates with the presence of this labile selenoprotein complex and is absent in aselDor anxdhmutant. Enhanced biofilm density correlates strongly with higher levels of extracellular peroxide, which is produced upon the addition of selenite to TSBG. Peroxide levels are not increased in either theselDor thexdhmutant upon addition of selenite. Extracellular superoxide production, a phenomenon well established to be linked to clinical isolates, is abolished in both mutant strains. Taken together, these data provide evidence that an SDMH is involved in biofilm formation inEnterococcus faecalis, contributing to oxidant production either directly or alternatively through its involvement in redox-dependent processes linked to oxidant production.
Participation of Chromosome Segregation Protein ParAI ofVibrio choleraein Chromosome Replication
Authors: Kadoya Ryosuke , Baek Jong Hwan , Sarker Arnab , Chattoraj Dhruba K.
Published: January 2011

Vibrio choleraecarries homologs of plasmid-borneparAandparBgenes on both of its chromosomes. Thepargenes help to segregate many plasmids and chromosomes. Here we have studied thepargenes ofV. choleraechromosome I. Earlier studies suggested that ParBI binds to the centromeric siteparSInear the origin of replication (oriI), andparSI-ParBI complexes are placed at the cell poles by ParAI. Deletion ofparAIandparSIcaused the origin-proximal DNA to be less polar. Here we found that deletion ofparBIalso resulted in a less polar localization oforiI. However, unlike the deletion ofparAI, the deletion ofparBIincreased theoriInumber. Replication was normal when bothparAIandparBIwere deleted, suggesting that ParBI mediates its action through ParAI. Overexpression of ParAI in aparABI-deleted strain also increased the DNA content. The results are similar to those found forBacillus subtilis, where ParA (Soj) stimulates replication and this activity is repressed by ParB (SpoOJ). As inB. subtilis, the stimulation of replication most likely involves the replication initiator DnaA. Our results indicate that control of chromosomal DNA replication is an additional function of chromosomalpargenes conserved across the Gram-positive/Gram-negative divide.
The MreB-Like Protein Mbl ofStreptomyces coelicolorA3(2) Depends on MreB for Proper Localization and Contributes to Spore Wall Synthesis
Authors: Heichlinger Andrea , Ammelburg Moritz , Kleinschnitz Eva-Maria , Latus Annette , Maldener Iris , Flärdh Klas , Wohlleben Wolfgang , Muth Günther
Published: January 2011

Most bacteria with a rod-shaped morphology contain an actin-like cytoskeleton consisting of MreB polymers, which form helical spirals underneath the cytoplasmic membrane to direct peptidoglycan synthesis for the elongation of the cell wall. In contrast, MreB ofStreptomyces coelicoloris not required for vegetative growth but has a role in sporulation. Besides MreB,S. coelicolorencodes two further MreB-like proteins, Mbl and SCO6166, whose function is unknown. Whereas MreB and Mbl are highly similar, SCO6166 is shorter, lacking the subdomains IB and IIB of actin-like proteins. Here, we showed that MreB and Mbl are not functionally redundant but cooperate in spore wall synthesis. Expression analysis by semiquantitative reverse transcription-PCR revealed distinct expression patterns.mreBandmblare induced predominantly during morphological differentiation. In contrast,sco6166is strongly expressed during vegetative growth but switched off during sporulation. All genes could be deleted without affecting viability. Even a ΔmreBΔmbldouble mutant was viable. Δsco6166had a wild-type phenotype. ΔmreB, Δmbl, and ΔmreBΔmblproduced swollen, prematurely germinating spores that were sensitive to various kinds of stress, suggesting a defect in spore wall integrity. During aerial mycelium formation, an Mbl-mCherry fusion protein colocalized with an MreB-enhanced green fluorescent protein (MreB-eGFP) fusion protein at the sporulation septa. Whereas MreB-eGFP localized properly in the Δmblmutant, Mbl-mCherry localization depended on the presence of a functional MreB protein. Our results revealed that MreB and Mbl cooperate in the synthesis of the thickened spore wall, while SCO6166 has a nonessential function during vegetative growth.
Domain Analysis of Protein P30 in
Mycoplasma pneumoniae
Cytadherence and Gliding Motility
Authors: Chang How-Yi , Jordan Jarrat L. , Krause Duncan C.
Published: January 2011

The cell wall-less prokaryote
Mycoplasma pneumoniae
causes bronchitis and atypical pneumonia in humans. Mycoplasma attachment and gliding motility are required for colonization of the respiratory epithelium and are mediated largely by a differentiated terminal organelle. P30 is a membrane protein at the distal end of the terminal organelle and is required for cytadherence and gliding motility, but little is known about the functional role of its specific domains. In the current study, domain deletion and substitution derivatives of P30 were engineered and introduced into a P30 null mutant by transposon delivery to assess their ability to rescue P30 function. Domain deletions involving the extracellular region of P30 severely impacted protein stability and adherence and gliding function, as well as the capacity to stabilize terminal organelle protein P65. Amino acid substitutions in the transmembrane domain revealed specific residues uniquely required for P30 stability and function, perhaps to establish correct topography in the membrane for effective alignment with binding partners. Deletions within the predicted cytoplasmic domain did not affect P30 localization or its capacity to stabilize P65 but markedly impaired gliding motility and cytadherence. The larger of two cytoplasmic domain deletions also appeared to remove the P30 signal peptide processing site, suggesting a larger leader peptide than expected. We propose that the P30 cytoplasmic domain may be required to link P30 to the terminal organelle core, to enable the P30 extracellular domain to achieve a functional conformation, or perhaps both.
Regulation of Catalase-Peroxidase KatG Is OxyR Dependent and Fur Independent in
Caulobacter crescentus
Authors: Italiani Valéria C. S. , da Silva Neto José F. , Braz Vânia S. , Marques Marilis V.
Published: January 2011

Most organisms that grow in the presence of oxygen possess catalases and/or peroxidases, which are necessary for scavenging the H
2
O
2
produced by aerobic metabolism. In this work we investigate the pathways that regulate the
Caulobacter crescentus katG
gene, encoding the only enzyme with catalase-peroxidase function in this bacterium. The transcriptional start site of the
katG
gene was determined, showing a short 5′ untranslated region. The
katG
regulatory region was mapped by serial deletions, and the results indicate that there is a single promoter, which is responsible for induction at stationary phase. An
oxyR
mutant strain was constructed; it showed decreased
katG
expression, and no KatG protein or catalase-peroxidase activity was detected in stationary-phase cell extracts, implying that OxyR is the main positive regulator of the
C. crescentus katG
gene. Purified OxyR protein bound to the
katG
regulatory region between nucleotides −42 and −91 from the transcription start site, as determined by a DNase I footprinting assay, and a canonical OxyR binding site was found in this region. Moreover, OxyR binding was shown to be redox dependent, given that only oxidized proteins bound adjacent to the −35 sequence of the promoter and the
katG
P1 promoter was activated by OxyR in an H
2
O
2
-dependent manner. On the other hand, this work showed that the iron-responsive regulator Fur does not regulate
C. crescentus katG
, since a
fur
mutant strain presented wild-type levels of
katG
transcription and catalase-peroxidase production and activity, and the purified Fur protein was not able to bind to the
katG
regulatory region.
Unusual Heme-Binding PAS Domain from YybT Family Proteins
Authors: Rao Feng , Ji Qiang , Soehano Ishin , Liang Zhao-Xun
Published: January 2011

YybT family proteins (COG3887) are functionally unknown proteins that are widely distributed among the firmicutes, including the human pathogensStaphylococcus aureusandListeria monocytogenes. Recent studies suggested that YybT family proteins are crucial for thein vivosurvival of bacterial pathogens during host infection. YybT family proteins contain an N-terminal domain that shares minimum sequence homology with Per-ARNT-Sim (PAS) domains. Despite the lack of an apparent residue for heme coordination, the putative PAS domains ofBsYybT andGtYybT, two representative members of the YybT family proteins fromBacillus subtilisandGeobacillus thermodenitrificans, respectively, are found to bindb-type heme with 1:1 stoichiometry. Heme binding suppresses the catalytic activity of the DHH/DHHA1 phosphodiesterase domain and the degenerate GGDEF domain. Absorption spectroscopic studies indicate that YybT proteins do not form stable oxyferrous complexes due to the rapid oxidation of the ferrous iron upon O2binding. The ferrous heme, however, forms a hexacoordinated complex with carbon monoxide (CO) and a pentacoordinated complex with nitric oxide (NO). The coordination of NO, but not CO, to the heme stimulates the phosphodiesterase activity. These results suggest that YybT family proteins function as stress-signaling proteins for monitoring cellular heme or the NO level by using a heme-binding PAS domain that features an unconventional heme coordination environment.
Enterococcus faecalis
Virulence Regulator FsrA Binding to Target Promoters
Authors: Del Papa María Florencia , Perego Marta
Published: January 2011

The FsrABDC signal transduction system is a major virulence regulator in
Enterococcus faecalis
. The FsrC sensor histidine kinase, upon activation by the gelatinase biosynthesis-activating pheromone (GBAP) peptide encoded by the
fsrBD
genes, phosphorylates the FsrA response regulator required for the transcription of the
fsrBDC
and the
gelE
-
sprE
genes from the
fsrB
promoter and the
gelE
promoter, respectively. FsrA belongs to the LytTR family of proteins, which includes other virulence regulators, such as AgrA of
Staphylococcus aureus
, AlgR of
Pseudomonas aeruginosa
, and VirR of
Clostridium perfringens
. The LytTR DNA-binding domain that characterizes these proteins generally binds to two imperfect direct repeats separated by a number of bases that place the repeats on the same face of the DNA helix. In this study, we demonstrated that FsrA also binds to two imperfect direct repeats separated by 13 bp, based on the consensus sequence of FsrA, T/AT/CAA/GGGAA/G, which is consistent with the binding characteristics of LytTR domains.
Combinatorial Regulation of
fmgD
by MrpC2 and FruA during
Myxococcus xanthus
Development
Authors: Lee Jun-seok , Son Bongjun , Viswanathan Poorna , Luethy Paul M. , Kroos Lee
Published: January 2011

Upon starvation, a dense population of rod-shaped
Myxococcus xanthus
bacteria coordinate their movements to construct mounds in which some of the cells differentiate to spherical spores. During this process of fruiting body formation, short-range C-signaling between cells regulates their movements and the expression of genes important for sporulation. C-signaling activates FruA, a transcription factor that binds cooperatively with another transcription factor, MrpC2, upstream of the
fmgA
and
fmgBC
promoters, activating transcription. We have found that a third C-signal-dependent gene, herein named
fmgD
, is subject to combinatorial control by FruA and MrpC2. The two proteins appear to bind cooperatively upstream of the
fmgD
promoter and activate transcription. FruA binds proximal to the
fmgD
promoter, as in the
fmgBC
promoter region, whereas MrpC2 binds proximal to the
fmgA
promoter. A novel feature of the
fmgD
promoter region is the presence of a second MrpC2 binding site partially overlapping the promoter and therefore likely to mediate repression. The downstream MrpC2 site appears to overlap the FruA site, so the two transcription factors may compete for binding, which in both cases appears to be cooperative with MrpC2 at the upstream site. We propose that binding of MrpC2 to the downstream site represses
fmgD
transcription until C-signaling causes the concentration of active FruA to increase sufficiently to outcompete the downstream MrpC2 for cooperative binding with the upstream MrpC2. This would explain why
fmgD
transcription begins later during development and is more dependent on C-signaling than transcription of
fmgA
and
fmgBC
.
Characteristics of people with recurrent ankle sprains: a systematic review with meta-analysis
Authors: Hiller Claire E , Nightingale Elizabeth J , Lin Chung-Wei Christine , Coughlan Garrett F , Caulfield Brian , Delahunt Eamonn
Published: January 2011

Objective

To examine whether people with recurrent ankle sprain, have specific physical and sensorimotor deficits.

Design

A systematic review of journal articles in English using electronic databases to September 2009. Included articles compared physical or sensorimotor measures in people with recurrent (≥2) ankle sprains and uninjured controls.

Main outcome groups

Outcome measures were grouped into: physical characteristics, strength, postural stability, proprioception, response to perturbation, biomechanics and functional tests. A meta-analysis was undertaken where comparable results within an outcome group were inconsistent.

Results

Fifty-five articles met the inclusion criteria. Compared with healthy controls, people with recurrent sprains demonstrated radiographic changes in the talus, changes in foot position during gait and prolonged time to stabilisation after a jump. There were no differences in ankle range of motion or functional test performance. Pooled results showed greater postural sway when standing with eyes closed (SMD=0.9, 95% CI 0.4 to 1.4) or on unstable surfaces (0.5, 0.1 to 1.0) and decreased concentric inversion strength (1.1, 0.2 to 2.1) but no difference in evertor strength, inversion joint position sense or peroneal latency in response to a perturbation.

Conclusion

There are specific impairments in people with recurrent ankle sprain but not necessarily in areas commonly investigated.
Injuries and illnesses of football players during the 2010 FIFA World Cup
Authors: Dvorak Jiri , Junge Astrid , Derman Wayne , Schwellnus Martin
Published: January 2011

Background

The incidence and characteristics of football injuries during matches in top-level international tournaments are well documented, but training injuries and illnesses during this period have rarely been studied.

Aim

To analyse the incidence and characteristics of injuries and illnesses incurred during the 2010 Fédération Internationale de Football Association (FIFA) World Cup.

Methods

The chief physicians of the 32 finalist teams reported daily all newly incurred injuries and illnesses of their players on a standardised medical report form.

Results

Out of 229 injuries reported, 82 match and 58 training injuries were expected to result in time loss, equivalent to an incidence of 40.1 match and 4.4 training injuries per 1000 h. Contact with another player was the most frequent cause of match (65%) and of training (40%) injuries. The most frequent diagnoses were thigh strain and ankle sprain. 99 illnesses of 89 (12%) players were reported. Illnesses were mainly infections of the respiratory or the digestive system. Most illnesses did not result in absence from training or match. The incidence of time-loss illnesses was 3.0 per 1000 player days.

Conclusion

The incidence of match injuries during the 2010 FIFA World Cup was significantly lower than in the three proceeding World Cups. This might be a result of more regard to injury prevention, less foul play and stricter refereeing. Tackling skills and fair play need to be improved to prevent contact injuries in training and matches. Prevention of illness should focus on reducing the risk of infections by considering the common modes of transmission and environmental conditions.
Impact of pesticide exposure misclassification on estimates of relative risks in the Agricultural Health Study
Authors: Blair Aaron , Thomas Kent , Coble Joseph , Sandler Dale P , Hines Cynthia J , Lynch Charles F , Knott Charles , Purdue Mark P , Zahm Shelia Hoar , Alavanja Michael C R , Dosemeci Mustafa , Kamel Freya , Hoppin Jane A , Freeman Laura Beane , Lubin Jay H
Published: January 2011

Background

The Agricultural Health Study (AHS) is a prospective study of licensed pesticide applicators and their spouses in Iowa and North Carolina. We evaluate the impact of occupational pesticide exposure misclassification on relative risks using data from the cohort and the AHS Pesticide Exposure Study (AHS/PES).

Methods

We assessed the impact of exposure misclassification on relative risks using the range of correlation coefficients observed between measured post-application urinary levels of 2,4-dichlorophenoxyacetic acid (2,4-D) and a chlorpyrifos metabolite and exposure estimates based on an algorithm from 83 AHS pesticide applications.

Results

Correlations between urinary levels of 2,4-D and a chlorpyrifos metabolite and algorithm estimated intensity scores were about 0.4 for 2,4-D (n=64), 0.8 for liquid chlorpyrifos (n=4) and 0.6 for granular chlorpyrifos (n=12). Correlations of urinary levels with kilograms of active ingredient used, duration of application, or number of acres treated were lower and ranged from −0.36 to 0.19. These findings indicate that a priori expert-derived algorithm scores were more closely related to measured urinary levels than individual exposure determinants evaluated here. Estimates of potential bias in relative risks based on the correlations from the AHS/PES indicate that non-differential misclassification of exposure using the algorithm would bias estimates towards the null, but less than that from individual exposure determinants.

Conclusions

Although correlations between algorithm scores and urinary levels were quite good (ie, correlations between 0.4 and 0.8), exposure misclassification would still bias relative risk estimates in the AHS towards the null and diminish study power.
Quality control in upper gastrointestinal endoscopy: detection rates of gastric cancer in Oxford 2005–2008
Authors: Vradelis S , Maynard N , Warren B F , Keshav S , Travis S P L
Published: January 2011

Background

Gastric cancer (GC) represents the sum of advanced gastric cancer (AGC) and early gastric cancer (EGC). Endoscopy (with biopsies) is the gold standard for detection of GC, but a false-negative rate of up to 19% is reported.

Aim

To determine whether patients with GC had had an oesophagogastroduodenoscopy (OGD) in the year preceding diagnosis that might reasonably have been expected to detect the cancer, as a measure of quality assurance of endoscopic practice.

Methods

Patients with histologically proven GC were identified from pathology records. Endoscopy reports and case notes were examined to identify any OGD before diagnosis, the interval and endoscopic findings. A false-negative OGD was defined as one where GC was neither suspected nor shown at pathology, but where a diagnosis of GC was made within 12 months.

Results

Between January 2005 and February 2008, 9764 OGDs were performed. GC was diagnosed in 74 patients (male/female ratio 2.89; median age 76, range 38–95). Nine (12%) patients had EGC. There were no differences in age, sex or symptoms between the EGC and AGC group. Sixty-eight of the 74 patients with GC (92%) presented with alarm symptoms. Ten of the 74 had had an OGD within 12 months before definitive diagnosis; all these were planned because of suspicious lesions. Significantly fewer biopsies were performed at OGDs preceding definitive diagnosis (median 2 (0–10) vs 6 (2–12); p=0.002).

Conclusion

False-negative rates of 0% (within 12 months) and 8% (within 3 years) for diagnosis of GC are reassuring, but an inadequate number of biopsies compromises the quality assurance of endoscopy. GC presents without alarm symptoms in <10%.
Cardiac myocyte remodeling mediated by N-cadherin-dependent mechanosensing
Authors: Chopra Anant , Tabdanov Erdem , Patel Hersh , Janmey Paul A. , Kresh J. Yasha
Published: January 2011

Cell-to-cell adhesions are crucial in maintaining the structural and functional integrity of cardiac cells. Little is known about the mechanosensitivity and mechanotransduction of cell-to-cell interactions. Most studies of cardiac mechanotransduction and myofibrillogenesis have focused on cell-extracellular matrix (ECM)-specific interactions. This study assesses the direct role of intercellular adhesion, specifically that of N-cadherin-mediated mechanotransduction, on the morphology and internal organization of neonatal ventricular cardiac myocytes. The results show that cadherin-mediated cell attachments are capable of eliciting a cytoskeletal network response similar to that of integrin-mediated force response and transmission, affecting myofibrillar organization, myocyte shape, and cortical stiffness. Traction forces mediated by N-cadherin were shown to be comparable to those sustained by ECM. The directional changes in predicted traction forces as a function of imposed loads (gel stiffness) provide the added evidence that N-cadherin is a mechanoresponsive adhesion receptor. Strikingly, the mechanical sensitivity response (gain) in terms of the measured cell-spread area as a function of imposed load (adhesive substrate rigidity) was consistently higher for N-cadherin-coated surfaces compared with ECM protein-coated surfaces. In addition, the cytoskeletal architecture of myocytes on an N-cadherin adhesive microenvironment was characteristically different from that on an ECM environment, suggesting that the two mechanotransductive cell adhesion systems may play both independent and complementary roles in myocyte cytoskeletal spatial organization. These results indicate that cell-to-cell-mediated force perception and transmission are involved in the organization and development of cardiac structure and function.
Soluble guanylate cyclase-α1is required for the cardioprotective effects of inhaled nitric oxide
Authors: Nagasaka Yasuko , Buys Emmanuel S. , Spagnolli Ester , Steinbicker Andrea U. , Hayton Sarah R. , Rauwerdink Kristen M. , Brouckaert Peter , Zapol Warren M. , Bloch Kenneth D.
Published: January 2011

Reperfusion injury limits the benefits of revascularization in the treatment of myocardial infarction (MI). Breathing nitric oxide (NO) reduces cardiac ischemia-reperfusion injury in animal models; however, the signaling pathways by which inhaled NO confers cardioprotection remain uncertain. The objective of this study was to learn whether inhaled NO reduces cardiac ischemia-reperfusion injury by activating the cGMP-generating enzyme, soluble guanylate cyclase (sGC), and to investigate whether bone marrow (BM)-derived cells participate in the sGC-mediated cardioprotective effects of inhaled NO. Wild-type (WT) mice and mice deficient in the sGC α1-subunit (sGCα1−/−mice) were subjected to cardiac ischemia for 1 h, followed by 24 h of reperfusion. During ischemia and for the first 10 min of reperfusion, mice were ventilated with oxygen or with oxygen supplemented with NO (80 parts per million). The ratio of MI size to area at risk (MI/AAR) did not differ in WT and sGCα1−/−mice that did not breathe NO. Breathing NO decreased MI/AAR in WT mice (41%, P = 0.002) but not in sGCα1−/−mice (7%, P = not significant). BM transplantation was performed to restore WT BM-derived cells to sGCα1−/−mice. Breathing NO decreased MI/AAR in sGCα1−/−mice carrying WT BM (39%, P = 0.031). In conclusion, these results demonstrate that a global deficiency of sGCα1does not alter the degree of cardiac ischemia-reperfusion injury in mice. The cardioprotective effects of inhaled NO require the presence of sGCα1. Moreover, our studies suggest that BM-derived cells are key mediators of the ability of NO to reduce cardiac ischemia-reperfusion injury.
Ivabradine reduces heart rate while preserving metabolic fluxes and energy status of healthy normoxic working hearts
Authors: Lauzier Benjamin , Vaillant Fanny , Gélinas Roselle , Bouchard Bertrand , Brownsey Roger , Thorin Eric , Tardif Jean-Claude , Des Rosiers Christine
Published: January 2011

Heart rate reduction (HRR) is an important target in the management of patients with chronic stable angina. Most available drugs for HRR, such as β-blockers, have adverse effects, including on cardiac energy substrate metabolism, a well-recognized determinant of cardiac homeostasis. This study aimed at 1) testing whether HRR by ivabradine (IVA) alters substrate metabolism in the healthy normoxic working heart and 2) comparing the effect of IVA with that of the β-blocker metoprolol (METO). This was assessed using our well-established model of ex vivo mouse heart perfusion in the working mode, which enables concomitant evaluation of myocardial contractility and metabolic fluxes using 13C-labeled substrates. Hearts were perfused in the absence (controls; n = 10) or presence of IVA ( n = 10, 3 μM) with or without atrial pacing to abolish HRR in the IVA group. IVA significantly reduced HR (35 ± 5%) and increased stroke volume (39 ± 9%) while maintaining similar cardiac output, contractility, power, and efficiency. Effects of IVA on HR and stroke volume were reversed by atrial pacing. At the metabolic level, IVA did not impact on substrate selection to citrate formation, rates of glycolysis, or tissue levels of high-energy phosphates. In contrast, METO, at concentrations up to 40 μM, decreased markedly cardiac function (flow: 25 ± 6%; stroke volume: 30 ± 10%; contractility: 31 ± 9%) as well as glycolysis (2.9-fold) but marginally affected HR. Collectively, these results demonstrate that IVA selectively reduces HR while preserving energy substrate metabolism of normoxic healthy working mouse hearts perfused ex vivo, a model that mimics to some extent the denervated transplanted heart. Our results provide the impetus for testing selective HRR by IVA on cardiac substrate metabolism in pathological models.
Pressure-induced myogenic tone and role of 20-HETE in mediating autoregulation of cerebral blood flow
Authors: Harder David R. , Narayanan Jayashree , Gebremedhin Debebe
Published: January 2011

While myogenic force in response to a changing arterial pressure has been described early in the 20th century, it was not until 1984 that the effect of a sequential increase in intraluminal pressure on cannulated cerebral arterial preparations was found to result in pressure-dependent membrane depolarization associated with spike generation and reduction in lumen diameter. Despite a great deal of effort by different laboratories and investigators, the identification of the existence of a mediator of the pressure-induced myogenic constriction in arterial muscle remained a challenge. It was the original finding by our laboratory that demonstrated the capacity of cerebral arterial muscle cells to express the cytochrome P-450 4A enzyme that catalyzes the formation of the potent vasoconstrictor 20-hydroxyeicosatetraenoic acid (20-HETE) from arachidonic acid, the production of which in cerebral arterial muscle cells increases with the elevation in intravascular pressure. 20-HETE activates protein kinase C and causes the inhibition of Ca2+-activated K+channels, depolarizes arterial muscle cell membrane, and activates L-type Ca2+channel to increase intracellular Ca2+levels and evoke vasoconstriction. The inhibition of 20-HETE formation attenuates pressure-induced arterial myogenic constriction in vitro and blunts the autoregulation of cerebral blood flow in vivo . We suggest that the formation and action of cytochrome P-450-derived 20-HETE in cerebral arterial muscle could play a critically important role in the control of cerebral arterial tone and the autoregulation of cerebral blood flow under physiological conditions.
Functional mathematical model of dual pathway AV nodal conduction
Authors: Climent A. M. , Guillem M. S. , Zhang Y. , Millet J. , Mazgalev T. N.
Published: January 2011

Dual atrioventricular (AV) nodal pathway physiology is described as two different wave fronts that propagate from the atria to the His bundle: one with a longer effective refractory period [fast pathway (FP)] and a second with a shorter effective refractory period [slow pathway (SP)]. By using His electrogram alternance, we have developed a mathematical model of AV conduction that incorporates dual AV nodal pathway physiology. Experiments were performed on five rabbit atrial-AV nodal preparations to develop and test the presented model. His electrogram alternances from the inferior margin of the His bundle were used to identify fast and slow wave front propagations. The ability to predict AV conduction time and the interaction between FP and SP wave fronts have been analyzed during regular and irregular atrial rhythms (e.g., atrial fibrillation). In addition, the role of dual AV nodal pathway wave fronts in the generation of Wenckebach periodicities has been illustrated. Finally, AV node ablative modifications have been evaluated. The model accurately reproduced interactions between FP and SP during regular and irregular atrial pacing protocols. In all experiments, specificity and sensitivity higher than 85% were obtained in the prediction of the pathway responsible for conduction. It has been shown that, during atrial fibrillation, the SP ablation significantly increased the mean HH interval (204 ± 39 vs. 274 ± 50 ms, P < 0.05), whereas FP ablation did not produce significant slowing of ventricular rate. The presented mathematical model can help in understanding some of the intriguing AV node mechanisms and should be considered as a step forward in the studies of AV nodal conduction.
Pulsatile to-fro flow induces greater and sustained expression of tissue factor RNA in HUVEC than unidirectional laminar flow
Authors: Abe Ryuzo , Yamashita Norio , Rochier Adrienne , Abe Rei , Nixon Alexander , Madri Joseph A. , Sumpio Bauer E.
Published: January 2011

Tissue factor (TF) is expressed in atherosclerotic lesions. Since mechanical forces influence endothelial cell (EC) function and are thought to account for the unique distribution of atherosclerosis in areas exposed to disturbed flow, we hypothesized that disturbed to-fro flow (TFF) and unidirectional pulsatile forward flow (PFF) would have different effects on TF expression in EC. TF RNA expression in HUVEC exposed to mechanical stress in the presence or absence of chemical stimulation with thrombin was determined. TFF induced a significantly higher TF expression than PFF that was sustained for 8 h. Combination of mechanical and chemical stimuli induced significantly higher TF expression than only mechanical stresses, and this effect was synergistic in both TFF and PFF. The MAPK p38 inhibitor SB-203580 significantly inhibited TF expression induced by mechanical and chemical stimulations, but the MEK inhibitor PD-98059 did not inhibit TF induced by TFF. Immunoblotting revealed that ERK1/2 phosphorylation induced by TFF was sustained for 120 min, whereas that induced by PFF was not. We conclude that disturbed flow induced greater and sustained amplification of TF expression, and this synergistic effect may be regulated by p38 MAPK and ERK1/2. These results provide added insight into the mechanism of atherosclerosis in areas of disturbed flow.
Androgen stimulates endothelial cell proliferation via an androgen receptor/VEGF/cyclin A-mediated mechanism
Authors: Cai Jingjing , Hong Yuan , Weng Chunyan , Tan Chen , Imperato-McGinley Julianne , Zhu Yuan-Shan
Published: January 2011

Growing evidences support that androgen displays beneficial effects on cardiovascular functions although the mechanism of androgen actions remains to be elucidated. Modulation of endothelial cell growth and function is a potential mechanism of androgen actions. We demonstrated in the present study that androgens [dihydrotestosterone (DHT) and testosterone], but not 17β-estradiol, produced a time- and dose-dependent induction of cell proliferation in primary human aortic endothelial cells (HAECs) as evident by increases in viable cell number and DNA biosynthesis. Real-time qRT-PCR analysis showed that DHT induced androgen receptor (AR), cyclin A, cyclin D1, and vascular endothelial growth factor (VEGF) gene expression in a dose- and time-dependent manner. The addition of casodex, a specific AR antagonist, or transfection of a specific AR siRNA blocked DHT-induced cell proliferation and target gene expression, indicating that the DHT effects are mediated via AR. Moreover, coadministration of SU5416 to block VEGF receptors, or transfection of a specific VEGF-A siRNA to knockdown VEGF expression, produced a dose-dependent blockade of DHT induction of cell proliferation and cyclin A gene expression. Interestingly, roscovitine, a selective cyclin-dependent kinase inhibitor, also blocked the DHT stimulation of cell proliferation with a selective inhibition of DHT-induced VEGF-A expression. These results indicate that androgens acting on AR stimulate cell proliferation through upregulation of VEGF-A, cyclin A, and cyclin D1 in HAECs, which may be beneficial to cardiovascular functions since endothelial cell proliferation could assist the repair of endothelial injury/damage in cardiovascular system.
Hypoxia increases transepithelial electrical conductance and reduces occludin at the plasma membrane in alveolar epithelial cells via PKC-ζ and PP2A pathway
Authors: Caraballo Juan Carlos , Yshii Cecilia , Butti Maria L. , Westphal Whitney , Borcherding Jennifer A. , Allamargot Chantal , Comellas Alejandro P.
Published: January 2011

During pulmonary edema, the alveolar space is exposed to a hypoxic environment. The integrity of the alveolar epithelial barrier is required for the reabsorption of alveolar fluid. Tight junctions (TJ) maintain the integrity of this barrier. We set out to determine whether hypoxia creates a dysfunctional alveolar epithelial barrier, evidenced by an increase in transepithelial electrical conductance (Gt), due to a decrease in the abundance of TJ proteins at the plasma membrane. Alveolar epithelial cells (AEC) exposed to mild hypoxia (Po2= 50 mmHg) for 30 and 60 min decreased occludin abundance at the plasma membrane and significantly increased Gt. Other cell adhesion molecules such as E-cadherin and claudins were not affected by hypoxia. AEC exposed to hypoxia increased superoxide, but not hydrogen peroxide (H2O2). Overexpression of superoxide dismutase 1 (SOD1) but not SOD2 prevented the hypoxia-induced Gtincrease and occludin reduction in AEC. Also, overexpression of catalase had a similar effect as SOD1, despite not detecting any increase in H2O2during hypoxia. Blocking PKC-ζ and protein phosphatase 2A (PP2A) prevented the hypoxia-induced occludin reduction at the plasma membrane and increase in Gt. In summary, we show that superoxide, PKC-ζ, and PP2A are involved in the hypoxia-induced increase in Gtand occludin reduction at the plasma membrane in AEC.
Proteolytic release of the receptor for advanced glycation end products from in vitro and in situ alveolar epithelial cells
Authors: Yamakawa Naoko , Uchida Tokujiro , Matthay Michael A. , Makita Koshi
Published: January 2011

Although the receptor for advanced glycation end products (RAGE) has been used as a biological marker of alveolar epithelial cell injury in clinical studies, the mechanism for release of soluble RAGE from lung epithelial cells has not been well studied. Therefore, these studies were designed to determine the mechanism for release of soluble RAGE after lipopolysaccharide (LPS) challenge. For these purposes, alveolar epithelial cells from rat lungs were cultured on Transwell inserts, and LPS was added to the apical side (500 μg/ml) for 16 h on day 7. On day 7, RAGE was expressed predominantly in surfactant protein D-negative cells, and LPS challenge induced release of RAGE into the medium. This response was partially blocked by matrix metalloproteinase (MMP) inhibitors. Transcripts of MMP-3 and MMP-13 were upregulated by LPS, whereas RAGE transcripts did not change. Proteolysis by MMP-3 and MMP-13 resulted in soluble RAGE expression in the bronchoalveolar lavage fluid in the in situ rat lung, and this reaction was inhibited by MMP inhibitors. In human studies, both MMP-3 and -13 antigen levels were significantly correlated with the level of RAGE in pulmonary edema fluid samples. These results support the conclusion that release of RAGE is primarily mediated by proteolytic damage in alveolar epithelial cells in the lung, caused by proteases in acute inflammatory conditions in the distal air spaces.