bluuebunny/crossref_metadata_2025 huggingface dataset:
Cue weight in the perception of Trique glottal consonants
Authors: DiCanio Christian
Published: February 2014

This paper examines the perceptual weight of cues to the coda glottal consonant contrast in Trique (Oto-Manguean) with native listeners. The language contrasts words with no coda (/Vː/) from words with a coda glottal stop (/VɁ/) or breathy coda (/Vɦ/). The results from a speeded AX (same–different) lexical discrimination task show high accuracy in lexical identification for the /Vː/-/Vɦ/ contrast, but lower accuracy for the other contrasts. The second experiment consists of a labeling task where the three acoustic dimensions that distinguished the glottal consonant codas in production [duration, the amplitude difference between the first two harmonics (H1-H2), and F0] were modified orthogonally using step-wise resynthesis. This task determines the relative weight of each dimension in phonological categorization. The results show that duration was the strongest cue. Listeners were only sensitive to changes in H1-H2 for the /Vː/-/Vɦ/ and /Vː/-/VɁ/ contrasts when duration was ambiguous. Listeners were only sensitive to changes in F0 for the /Vː/-/Vɦ/ contrast when both duration and H1-H2 were ambiguous. The perceptual cue weighting for each contrast closely matches existing production data [DiCanio (2012 a). J. Phon. 40, 162–176] Cue weight differences in speech perception are explained by differences in step-interval size and the notion of adaptive plasticity [Francis et al. (2008). J. Acoust. Soc. Am. 124, 1234–1251; Holt and Lotto (2006). J. Acoust. Soc. Am. 119, 3059–3071].
Examining the robustness of automated aural classification of active sonar echoes
Authors: Murphy Stefan M. , Hines Paul C.
Published: February 2014

Active sonar systems are used to detect underwater man-made objects of interest (targets) that are too quiet to be reliably detected with passive sonar. Performance of active sonar can be degraded by false alarms caused by echoes returned from geological seabed structures (clutter) in shallow regions. To reduce false alarms, a method of distinguishing target echoes from clutter echoes is required. Research has demonstrated that perceptual-based signal features similar to those employed in the human auditory system can be used to automatically discriminate between target and clutter echoes, thereby reducing the number of false alarms and improving sonar performance. An active sonar experiment on the Malta Plateau in the Mediterranean Sea was conducted during the Clutter07 sea trial and repeated during the Clutter09 sea trial. The dataset consists of more than 95 000 pulse-compressed echoes returned from two targets and many geological clutter objects. These echoes were processed using an automatic classifier that quantifies the timbre of each echo using a number of perceptual signal features. Using echoes from 2007, the aural classifier was trained to establish a boundary between targets and clutter in the feature space. Temporal robustness was then investigated by testing the classifier on echoes from the 2009 experiment.
Altered Fecal Microbiota Composition Associated with Food Allergy in Infants
Authors: Ling Zongxin , Li Zailing , Liu Xia , Cheng Yiwen , Luo Yueqiu , Tong Xiaojuan , Yuan Li , Wang Yuezhu , Sun Jinbo , Li Lanjuan , Xiang Charlie
Published: February 2014

Increasing evidence suggests that perturbations in the intestinal microbiota composition of infants are implicated in the pathogenesis of food allergy (FA), while the actual structure and composition of the intestinal microbiota in human beings with FA remain unclear. Microbial diversity and composition were analyzed with parallel barcoded 454 pyrosequencing targeting the 16S rRNA gene hypervariable V1-V3 regions in the feces of 34 infants with FA (17 IgE mediated and 17 non-IgE mediated) and 45 healthy controls. Here, we showed that several key FA-associated bacterial phylotypes, but not the overall microbiota diversity, significantly changed in infancy fecal microbiota with FA and were associated with the development of FA. The proportion of abundant
Bacteroidetes
,
Proteobacteria
, and
Actinobacteria
phyla were significantly reduced, while the
Firmicutes
phylum was highly enriched in the FA group (
P
< 0.05). Abundant
Clostridiaceae
1 organisms were prevalent in infants with FA at the family level (
P
= 0.016). FA-enriched phylotypes negatively correlated with interleukin-10, for example, the genera
Enterococcus
and
Staphylococcus
. Despite profound interindividual variability, levels of 20 predominant genera were significantly different between the FA and healthy control groups (
P
< 0.05). Infants with IgE-mediated FA had increased levels of
Clostridium sensu stricto
and
Anaerobacter
and decreased levels of
Bacteroides
and
Clostridium
XVIII (
P
< 0.05). A positive correlation was observed between
Clostridium sensu stricto
and serum-specific IgE (
R
= 0.655,
P
< 0.001). The specific microbiota signature could distinguish infants with IgE-mediated FA from non-IgE-mediated ones. Detailed microbiota analysis of a well-characterized cohort of infants with FA showed that dysbiosis of fecal microbiota with several FA-associated key phylotypes may play a pathogenic role in FA.
New Vectors for Chromosomal Integration Enable High-Level Constitutive or Inducible Magnetosome Expression of Fusion Proteins in Magnetospirillum gryphiswaldense
Authors: Borg Sarah , Hofmann Julia , Pollithy Anna , Lang Claus , Schüler Dirk
Published: February 2014

The alphaproteobacterium
Magnetospirillum gryphiswaldense
biomineralizes magnetosomes, which consist of monocrystalline magnetite cores enveloped by a phospholipid bilayer containing specific proteins. Magnetosomes represent magnetic nanoparticles with unprecedented magnetic and physicochemical characteristics. These make them potentially useful in a number of biotechnological and biomedical applications. Further functionalization can be achieved by expression of foreign proteins via genetic fusion to magnetosome anchor peptides. However, the available genetic tool set for strong and controlled protein expression in magnetotactic bacteria is very limited. Here, we describe versatile vectors for either inducible or high-level constitutive expression of proteins in
M. gryphiswaldense
. The combination of an engineered native P

mamDC

promoter with a codon-optimized
egfp
gene (Mag-
egfp
) resulted in an 8-fold increase in constitutive expression and in brighter fluorescence. We further demonstrate that the widely used P

tet

promoter is functional and tunable in
M. gryphiswaldense
. Stable and uniform expression of the EGFP and β-glucuronidase (GusA) reporters was achieved by single-copy chromosomal insertion via Tn
5
-mediated transposition. In addition, gene duplication by Mag-EGFP–EGFP fusions to MamC resulted in further increased magnetosome expression and fluorescence. Between 80 and 210 (for single MamC–Mag-EGFP) and 200 and 520 (for MamC–Mag-EGFP–EGFP) GFP copies were estimated to be expressed per individual magnetosome particle.
Characterization of Temperate Phages Infecting Clostridium difficile Isolates of Human and Animal Origins
Authors: Sekulovic Ognjen , Garneau Julian R. , Néron Audrey , Fortier Louis-Charles
Published: February 2014

Clostridium difficile
is a Gram-positive pathogen infecting humans and animals. Recent studies suggest that animals could represent potential reservoirs of
C. difficile
that could then transfer to humans. Temperate phages contribute to the evolution of most bacteria, for example, by promoting the transduction of virulence, fitness, and antibiotic resistance genes. In
C. difficile
, little is known about their role, mainly because suitable propagating hosts and conditions are lacking. Here we report the isolation, propagation, and preliminary characterization of nine temperate phages from animal and human
C. difficile
isolates. Prophages were induced by UV light from 58
C. difficile
isolates of animal and human origins. Using soft agar overlays with 27 different
C. difficile
test strains, we isolated and further propagated nine temperate phages: two from horse isolates (ϕCD481-1 and ϕCD481-2), three from dog isolates (ϕCD505, ϕCD506, and ϕCD508), and four from human isolates (ϕCD24-2, ϕCD111, ϕCD146, and ϕCD526). Two phages are members of the
Siphoviridae
family (ϕCD111 and ϕCD146), while the others are
Myoviridae
phages. Pulsed-field gel electrophoresis and restriction enzyme analyses showed that all of the phages had unique double-stranded DNA genomes of 30 to 60 kb. Phages induced from human
C. difficile
isolates, especially the members of the
Siphoviridae
family, had a broader host range than phages from animal
C. difficile
isolates. Nevertheless, most of the phages could infect both human and animal strains. Phage transduction of antibiotic resistance was recently reported in
C. difficile
. Our findings therefore call for further investigation of the potential risk of transduction between animal and human
C. difficile
isolates.
Role of the Alternaria alternata Blue-Light Receptor LreA (White-Collar 1) in Spore Formation and Secondary Metabolism
Authors: Pruß Sonja , Fetzner Ramona , Seither Kristin , Herr Andreas , Pfeiffer Erika , Metzler Manfred , Lawrence Christopher B. , Fischer Reinhard
Published: February 2014

Alternaria alternata
is a filamentous fungus that causes considerable loss of crops of economically important feed and food worldwide. It produces more than 60 different secondary metabolites, among which alternariol (AOH) and altertoxin (ATX) are the most important mycotoxins. We found that mycotoxin production and spore formation are regulated by light in opposite ways. Whereas spore formation was largely decreased under light conditions, the production of AOH was stimulated 2- to 3-fold. ATX production was even strictly dependent on light. All light effects observed could be triggered by blue light, whereas red light had only a minor effect. Inhibition of spore formation by light was reversible after 1 day of incubation in the dark. We identified orthologues of genes encoding the
Neurospora crassa
blue-light-perceiving white-collar proteins, a cryptochrome, a phytochrome, and an opsin-related protein in the genome of
A. alternata
. Deletion of the white-collar 1 (WC-1) gene (
lreA
) resulted in derepression of spore formation in dark and in light. ATX formation was strongly induced in the dark in the
lreA
mutant, suggesting a repressing function of LreA, which appears to be released in the wild type after blue-light exposure. In addition, light induction of AOH formation was partially dependent on LreA, suggesting also an activating function.
A. alternata
Δ
lreA
was still able to partially respond to blue light, indicating the action of another blue-light receptor system.
Reduction of Ethanol Yield and Improvement of Glycerol Formation by Adaptive Evolution of the Wine Yeast Saccharomyces cerevisiae under Hyperosmotic Conditions
Authors: Tilloy Valentin , Ortiz-Julien Anne , Dequin Sylvie
Published: February 2014

There is a strong demand from the wine industry for methodologies to reduce the alcohol content of wine without compromising wine's sensory characteristics. We assessed the potential of adaptive laboratory evolution strategies under hyperosmotic stress for generation ofSaccharomyces cerevisiaewine yeast strains with enhanced glycerol and reduced ethanol yields. Experimental evolution on KCl resulted, after 200 generations, in strains that had higher glycerol and lower ethanol production than the ancestral strain. This major metabolic shift was accompanied by reduced fermentative capacities, suggesting a trade-off between high glycerol production and fermentation rate. Several evolved strains retaining good fermentation performance were selected. These strains produced more succinate and 2,3-butanediol than the ancestral strain and did not accumulate undesirable organoleptic compounds, such as acetate, acetaldehyde, or acetoin. They survived better under osmotic stress and glucose starvation conditions than the ancestral strain, suggesting that the forces that drove the redirection of carbon fluxes involved a combination of osmotic and salt stresses and carbon limitation. To further decrease the ethanol yield, a breeding strategy was used, generating intrastrain hybrids that produced more glycerol than the evolved strain. Pilot-scale fermentation on Syrah using evolved and hybrid strains produced wine with 0.6% (vol/vol) and 1.3% (vol/vol) less ethanol, more glycerol and 2,3-butanediol, and less acetate than the ancestral strain. This work demonstrates that the combination of adaptive evolution and breeding is a valuable alternative to rational design for remodeling the yeast metabolic network.
Microbial Species Diversity, Community Dynamics, and Metabolite Kinetics of Water Kefir Fermentation
Authors: Laureys David , De Vuyst Luc
Published: February 2014

Water kefir is a sour, alcoholic, and fruity fermented beverage of which the fermentation is started with water kefir grains. These water kefir grains consist of polysaccharide and contain the microorganisms responsible for the water kefir fermentation. In this work, a water kefir fermentation process was followed as a function of time during 192 h to unravel the community dynamics, the species diversity, and the kinetics of substrate consumption and metabolite production. The majority of the water kefir ecosystem was found to be present on the water kefir grains. The most important microbial species present wereLactobacillus casei/paracasei,Lactobacillus harbinensis,Lactobacillus hilgardii,Bifidobacterium psychraerophilum/crudilactis,Saccharomyces cerevisiae, andDekkera bruxellensis. The microbial species diversities in the water kefir liquor and on the water kefir grains were similar and remained stable during the whole fermentation process. The major substrate, sucrose, was completely converted after 24 h of fermentation, which coincided with the production of the major part of the water kefir grain polysaccharide. The main metabolites of the fermentation were ethanol and lactic acid. Glycerol, acetic acid, and mannitol were produced in low concentrations. The major part of these metabolites was produced during the first 72 h of fermentation, during which the pH decreased from 4.26 to 3.45. The most prevalent volatile aroma compounds were ethyl acetate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, and ethyl decanoate, which might be of significance with respect to the aroma of the end product.
TiO
2
Photocatalysis Damages Lipids and Proteins in Escherichia coli
Authors: Carré Gaëlle , Hamon Erwann , Ennahar Saïd , Estner Maxime , Lett Marie-Claire , Horvatovich Peter , Gies Jean-Pierre , Keller Valérie , Keller Nicolas , Andre Philippe
Published: February 2014

This study investigates the mechanisms of UV-A (315 to 400 nm) photocatalysis with titanium dioxide (TiO
2
) applied to the degradation of
Escherichia coli
and their effects on two key cellular components: lipids and proteins. The impact of TiO
2
photocatalysis on
E. coli
survival was monitored by counting on agar plate and by assessing lipid peroxidation and performing proteomic analysis. We observed through malondialdehyde quantification that lipid peroxidation occurred during the photocatalytic process, and the addition of superoxide dismutase, which acts as a scavenger of the superoxide anion radical (O
2
·
−
), inhibited this effect by half, showing us that O
2
·
−
radicals participate in the photocatalytic antimicrobial effect. Qualitative analysis using two-dimensional electrophoresis allowed selection of proteins for which spot modifications were observed during the applied treatments. Two-dimensional electrophoresis highlighted that among the selected protein spots, 7 and 19 spots had already disappeared in the dark in the presence of 0.1 g/liter and 0.4 g/liter TiO
2
, respectively, which is accounted for by the cytotoxic effect of TiO
2
. Exposure to 30 min of UV-A radiation in the presence of 0.1 g/liter and 0.4 g/liter TiO
2
increased the numbers of missing spots to 14 and 22, respectively. The proteins affected by photocatalytic oxidation were strongly heterogeneous in terms of location and functional category. We identified several porins, proteins implicated in stress response, in transport, and in bacterial metabolism. This study reveals the simultaneous effects of O
2
·
−
on lipid peroxidation and on the proteome during photocatalytic treatment and therefore contributes to a better understanding of molecular mechanisms in antibacterial photocatalytic treatment.
Conversion of 4-Hydroxybutyrate to Acetyl Coenzyme A and Its Anapleurosis in the Metallosphaera sedula 3-Hydroxypropionate/4-Hydroxybutyrate Carbon Fixation Pathway
Authors: Hawkins Aaron B. , Adams Michael W. W. , Kelly Robert M.
Published: February 2014

The extremely thermoacidophilic archaeon
Metallosphaera sedula
(optimum growth temperature, 73°C, pH 2.0) grows chemolithoautotrophically on metal sulfides or molecular hydrogen by employing the 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) carbon fixation cycle. This cycle adds two CO
2
molecules to acetyl coenzyme A (acetyl-CoA) to generate 4HB, which is then rearranged and cleaved to form two acetyl-CoA molecules. Previous metabolic flux analysis showed that two-thirds of central carbon precursor molecules are derived from succinyl-CoA, which is oxidized to malate and oxaloacetate. The remaining one-third is apparently derived from acetyl-CoA. As such, the steps beyond succinyl-CoA are essential for completing the carbon fixation cycle and for anapleurosis of acetyl-CoA. Here, the final four enzymes of the 3HP/4HB cycle, 4-hydroxybutyrate-CoA ligase (AMP forming) (Msed_0406), 4-hydroxybutyryl-CoA dehydratase (Msed_1321), crotonyl-CoA hydratase/(
S
)-3-hydroxybutyryl-CoA dehydrogenase (Msed_0399), and acetoacetyl-CoA β-ketothiolase (Msed_0656), were produced recombinantly in
Escherichia coli
, combined
in vitro
, and shown to convert 4HB to acetyl-CoA. Metabolic pathways connecting CO
2
fixation and central metabolism were examined using a gas-intensive bioreactor system in which
M. sedula
was grown under autotrophic (CO
2
-limited) and heterotrophic conditions. Transcriptomic analysis revealed the importance of the 3HP/4HB pathway in supplying acetyl-CoA to anabolic pathways generating intermediates in
M. sedula
metabolism. The results indicated that flux between the succinate and acetyl-CoA branches in the 3HP/4HB pathway is governed by 4-hydroxybutyrate-CoA ligase, possibly regulated posttranslationally by the protein acetyltransferase (Pat)/Sir2-dependent system. Taken together, this work confirms the final four steps of the 3HP/4HB pathway, thereby providing the framework for examining connections between CO
2
fixation and central metabolism in
M. sedula.
Infection by Toxoplasma gondii Specifically Induces Host c-Myc and the Genes This Pivotal Transcription Factor Regulates
Authors: Franco Magdalena , Shastri Anjali J. , Boothroyd John C.
Published: February 2014

Toxoplasma gondii
infection has previously been described to cause dramatic changes in the host transcriptome by manipulating key regulators, including STATs, NF-κB, and microRNAs. Here, we report that
Toxoplasma
tachyzoites also mediate rapid and sustained induction of another pivotal regulator of host cell transcription, c-Myc. This induction is seen in cells infected with all three canonical types of
Toxoplasma
but not the closely related apicomplexan parasite
Neospora caninum
. Coinfection of cells with both
Toxoplasma
and
Neospora
still results in an increase in the level of host c-Myc, showing that c-Myc is actively upregulated by
Toxoplasma
infection (rather than repressed by
Neospora
). We further demonstrate that this upregulation may be mediated through c-Jun N-terminal protein kinase (JNK) and is unlikely to be a nonspecific host response, as heat-killed
Toxoplasma
parasites do not induce this increase and neither do nonviable parasites inside the host cell. Finally, we show that the induced c-Myc is active and that transcripts dependent on its function are upregulated, as predicted. Hence, c-Myc represents an additional way in which
Toxoplasma
tachyzoites have evolved to specifically alter host cell functions during intracellular growth.
Differential Transcriptional Regulation of Aggregatibacter actinomycetemcomitans
lsrACDBFG
and
lsrRK
Operons by Integration Host Factor Protein
Authors: Torres-Escobar Ascención , Juárez-Rodríguez María Dolores , Demuth Donald R.
Published: February 2014

We previously showed that the
Aggregatibacter actinomycetemcomitans
lsrACDBFG
and
lsrRK
operons are regulated by LsrR and cyclic AMP receptor protein (CRP) and that proper regulation of the
lsr
locus is required for optimal biofilm growth by
A. actinomycetemcomitans
. Here, we identified sequences that reside immediately upstream from both the
lsrA
and
lsrR
start codons that closely resemble the consensus recognition sequence of
Escherichia coli
integration host factor (IHF) protein.
A. actinomycetemcomitans
IHFα and IHFβ were expressed and purified as hexahistidine fusion proteins, and using electrophoretic mobility shift assays (EMSAs), the IHFα-IHFβ protein complex was shown to bind to probes containing the putative IHF recognition sequences. In addition, single-copy chromosomal insertions of
lsrR
promoter-
lacZ
and
lsrA
promoter-
lacZ
transcriptional fusions in wild-type
A. actinomycetemcomitans
and Δ
ihfA
and Δ
ihfB
mutant strains showed that IHF differentially regulates the
lsr
locus and functions as a negative regulator of
lsrRK
and a positive regulator of
lsrACDBFG
. Deletion of
ihfA
or
ihfB
also reduced biofilm formation and altered biofilm architecture relative to the wild-type strain, and these phenotypes were partially complemented by a plasmid-borne copy of
ihfA
or
ihfB
. Finally, using 5′ rapid amplification of cDNA ends (RACE), two transcriptional start sites (TSSs) and two putative promoters were identified for
lsrRK
and three TSSs and putative promoters were identified for
lsrACDBFG
. The function of the two
lsrRK
promoters and the positive regulatory role of IHF in regulating
lsrACDBFG
expression were confirmed with a series of
lacZ
transcriptional fusion constructs. Together, our results highlight the complex transcriptional regulation of the
lsrACDBFG
and
lsrRK
operons and suggest that multiple promoters and the architecture of the
lsrACDBFG-lsrRK
intergenic region may control the expression of these operons.
The Bifunctional Cell Wall Hydrolase CwlT Is Needed for Conjugation of the Integrative and Conjugative Element ICEBs1in Bacillus subtilis and B. anthracis
Authors: DeWitt Tyler , Grossman Alan D.
Published: February 2014

The mobile genetic element ICEBs1is an integrative and conjugative element (ICE) found inBacillus subtilis. One of the ICEBs1genes,cwlT, encodes a cell wall hydrolase with two catalytic domains, a muramidase and a peptidase. We found thatcwlTis required for ICEBs1conjugation. We examined the role of each of the two catalytic domains and found that the muramidase is essential, whereas the peptidase is partially dispensable for transfer of ICEBs1. We also found that the putative signal peptide in CwlT is required for CwlT to function in conjugation, consistent with the notion that CwlT is normally secreted from the cytoplasm. We found that alteration of the putative lipid attachment site on CwlT had no effect on its role in conjugation, indicating that if CwlT is a lipoprotein, the lipid attachment is not required for conjugation. Finally, we found conditions supporting efficient transfer of ICEBs1into and out ofBacillus anthracisand thatcwlTwas needed for ICEBs1to function inB. anthracis. The mature cell wall ofB. anthracisis resistant to digestion by CwlT, indicating that CwlT might act during cell wall synthesis, before modifications of the peptidoglycan are complete.
Structure and Expression of Propanediol Utilization Microcompartments in Acetonema longum
Authors: Tocheva Elitza I. , Matson Eric G. , Cheng Sarah N. , Chen Wesley G. , Leadbetter Jared R. , Jensen Grant J.
Published: February 2014

Numerous bacteria assemble proteinaceous microcompartments to isolate certain biochemical reactions within the cytoplasm. The assembly, structure, contents, and functions of these microcompartments are active areas of research. Here we show that the Gram-negative sporulating bacterium
Acetonema longum
synthesizes propanediol utilization (PDU) microcompartments when starved or grown on 1,2-propanediol (1,2-PD) or rhamnose. Electron cryotomography of intact cells revealed that PDU microcompartments are highly irregular in shape and size, similar to purified PDU microcompartments from
Salmonella enterica
serovar Typhimurium LT2 that were imaged previously. Homology searches identified a 20-gene operon in
A. longum
that contains most of the structural, enzymatic, and regulatory genes thought to be involved in PDU microcompartment assembly and function. Transcriptional data on PduU and PduC, which are major structural and enzymatic proteins, respectively, as well as imaging, indicate that PDU microcompartment synthesis is induced within 24 h of growth on 1,2-PD and after 48 h of growth on rhamnose.
Diversity of O-Antigen Repeat Unit Structures Can Account for the Substantial Sequence Variation of Wzx Translocases
Authors: Hong Yaoqin , Reeves Peter R.
Published: February 2014

The most common system for synthesis of cell surface polysaccharides is the Wzx/Wzy-dependent pathway, which involves synthesis, on the cytoplasmic face of the cell membrane, of repeat units, which are then translocated to the periplasmic face by a Wzx translocase and then polymerized by Wzy to generate the polysaccharide. One such polysaccharide is O antigen, which is incorporated into lipopolysaccharide (LPS). The O antigen is extremely variable, with over 186 forms in
Escherichia coli
. Wzx proteins are also very diverse, but they have been thought to be specific only for the first sugar of the repeat units. However, recent studies demonstrated examples in which Wzx translocases have considerable preference for their native repeat unit, showing that specificity can extend well beyond the first sugar. These results appear to be in conflict with the early conclusions, but they involved specificity for side branch residues and could be a special case. Here we take six Wzx translocases that were critical in the earlier studies on the importance of the first sugar and assess their ability to translocate the
Escherichia coli
O16 and O111 repeat units. We use gene replacements to optimize maintenance of expression level and show that under these conditions the native translocases are the most effective for their native repeat unit, being, respectively, 64-fold and 4-fold more effective than the next best. We conclude that Wzx translocases are commonly adapted to their native repeat unit, which provides an explanation for the great diversity of
wzx
genes.
Characterization of the Operon Encoding the Holliday Junction Helicase RuvAB from Mycoplasma genitalium and Its Role in
mgpB
and
mgpC
Gene Variation
Authors: Burgos Raul , Totten Patricia A.
Published: February 2014

Mycoplasma genitalium
is an emerging sexually transmitted pathogen associated with reproductive tract disease in men and women, and it can persist for months to years despite the development of a robust antibody response. Mechanisms that may contribute to persistence
in vivo
include phase and antigenic variation of the MgpB and MgpC adhesins. These processes occur by segmental recombination between discrete variable regions within
mgpB
and
mgpC
and multiple archived donor sequences termed MgPa repeats (MgPars). The molecular factors governing
mgpB
and
mgpC
variation are poorly understood and obscured by the paucity of recombination genes conserved in the
M. genitalium
genome. Recently, we demonstrated the requirement for RecA using a quantitative PCR (qPCR) assay developed to measure recombination between the
mgpB
and
mgpC
genes and MgPars. Here, we expand these studies by examining the roles of
M. genitalium
ruvA
and
ruvB
homologs. Deletion of
ruvA
and
ruvB
impaired the ability to generate
mgpB
and
mgpC
phase and sequence variants, and these deficiencies could be complemented with wild-type copies, including the
ruvA
gene from
Mycoplasma pneumoniae
. In contrast,
ruvA
and
ruvB
deletions did not affect the sensitivity to UV irradiation, reinforcing our previous findings that the recombinational repair pathway plays a minor role in
M. genitalium
. Reverse transcription-PCR (RT-PCR) and primer extension analyses also revealed a complex transcriptional organization of the RuvAB system of
M. genitalium
, which is cotranscribed with two novel open reading frames (ORFs) (termed ORF1 and ORF2 herein) conserved only in
M. pneumoniae
. These findings suggest that these novel ORFs may play a role in recombination in these two closely related bacteria.
Multimorbidity in primary care in Portugal (MM-PT): a cross-sectional three-phase observational study protocol
Authors: Prazeres Filipe , Santiago Luiz
Published: February 2014

Introduction

Multimorbidity is defined as the co-occurrence of more than one chronic disease in one person without assigning an index disease. This rapidly increasing phenomenon markedly influences patients’ overall health, has major implications for effective provision of healthcare services and has a significant economic toll on individuals and society. Since Portugal is a country with a growing ageing population, a better understanding of the role of multimorbidity should be assessed. The aim of this study is to further the knowledge of the epidemiological factors associated with multimorbidity in Portugal, chiefly its prevalence and the health and social implications.

Methods and analysis

This study protocol describes a primary care nationwide three-phase study. The first phase is drawn to access the prevalence and patterns of multimorbidity. In the second phase, individual parameters are assessed, such as patients’ health-related quality of life, perceived family support and unmet health needs of patients with multimorbidity. The third and last phase of this study aims to characterise general practitioners’ knowledge, awareness and practices related to multimorbidity management.

Ethics and dissemination

The study will be conducted in accordance with the principles expressed in the Declaration of Helsinki. It has full approval from the Ethics Committee of the Faculty of Health Sciences, University of Beira Interior, and the Ethics Committee of the Central Health Region of Portugal. Study results will be published in peer-reviewed journals and presented at national and international conferences.
Factors that affect the uptake of community-based health insurance in low-income and middle-income countries: a systematic protocol
Authors: Adebayo Esther F , Ataguba John E , Uthman Olalekan A , Okwundu Charles I , Lamont Kim T , Wiysonge Charles S
Published: February 2014

Introduction

Many people residing in low-income and middle-income countries (LMICs) are regularly exposed to catastrophic healthcare expenditure. It is therefore pertinent that LMICs should finance their health systems in ways that ensure that their citizens can use needed healthcare services and are protected from potential impoverishment arising from having to pay for services. Ways of financing health systems include government funding, health insurance schemes and out-of-pocket payment. A health insurance scheme refers to pooling of prepaid funds in a way that allows for risks to be shared. The health insurance scheme particularly suitable for the rural poor and the informal sector in LMICs is community-based health insurance (CBHI), that is, insurance schemes operated by organisations other than governments or private for-profit companies. We plan to search for and summarise currently available evidence on factors associated with the uptake of CBHI, as we are not aware of previous systematic reviews that have looked at this important topic.

Methods

This is a protocol for a systematic review of the literature. We will include both quantitative and qualitative studies in this review. Eligible quantitative studies include intervention and observational studies. Qualitative studies to be included are focus group discussions, direct observations, interviews, case studies and ethnography. We will search EMBASE, PubMed, Scopus, ERIC, PsycInfo, Africa-Wide Information, Academic Search Premier, Business Source Premier, WHOLIS, CINAHL and the Cochrane Library for eligible studies available by 31 October 2013, regardless of publication status or language of publication. We will also check reference lists of included studies and proceedings of relevant conferences and contact researchers for eligible studies. Two authors will independently screen the search output, select studies and extract data, resolving discrepancies by consensus and discussion. Qualitative data will be extracted using standardised data extraction tools adapted from the Critical Appraisal Skills Program (CASP) qualitative appraisal checklist and put together in a thematic analysis where applicable. We will statistically pool data from quantitative studies in a meta-analysis; but if included quantitative studies differ significantly in study settings, design and/or outcome measures, we will present the findings in a narrative synthesis. This protocol has been registered with PROSPERO (ID=CRD42013006364).

Dissemination

Recommendations will be made to health policy makers, managers and researchers in LMICs to help inform them on ways to strengthen and increase the uptake of CBHI.
Influence of chronic exercise on carotid atherosclerosis in marathon runners
Authors: Taylor Beth A , Zaleski Amanda L , Capizzi Jeffrey A , Ballard Kevin D , Troyanos Christopher , Baggish Aaron L , D'Hemecourt Pierre A , Dada Marcin R , Thompson Paul D
Published: February 2014

Objectives

The effect of habitual, high-intensity exercise training on the progression of atherosclerosis is unclear. We assessed indices of vascular health (central systolic blood pressure (SBP) and arterial stiffness as well as carotid intima-medial thickness (cIMT)) in addition to cardiovascular risk factors of trained runners versus their untrained spouses or partners to evaluate the impact of exercise on the development of carotid atherosclerosis.

Setting

field study at Boston Marathon.

Participants

42 qualifiers (mean age±SD: 46±13 years, 21 women) for the 2012 Boston Marathon and their sedentary domestic controls (46±12 years, n=21 women).

Outcomes

We measured medical and running history, vital signs, anthropometrics, blood lipids, C reactive protein (CRP), 10 years Framingham risk, central arterial stiffness and SBP and cIMT.

Results

Multiple cardiovascular risk factors, including CRP, non-high-density lipoprotein cholesterol, triglycerides, heart rate, body weight and body mass index (all p<0.05), were reduced in the runners. The left and right cIMT, as well as central SBP, were not different between the two groups (all p>0.31) and were associated with age (all r≥0.41; p<0.01) and Framingham risk score (all r≥0.44; p<0.01) independent of exercise group (all p>0.08 for interactions). The amplification of the central pressure waveform (augmentation pressure at heart rate 75 bpm) was also not different between the two groups (p=0.07) but was related to age (p<0.01) and group (p=0.02) in a multiple linear regression model.

Conclusions

Habitual endurance exercise improves the cardiovascular risk profile, but does not reduce the magnitude of carotid atherosclerosis associated with age and cardiovascular risk factors.
Better training, Better care: Medical Procedures Training Initiative
Authors: Shafei Rachelle
Published: February 2014

Training in procedures has been identified as the top priority for core medical trainees (GMC trainee survey 2011). Current practice relies on each trainee being lucky enough to encounter each procedure during clinical rotations and during on-calls. Where trainees are not lucky enough, they are entering their registrar years without the skills to efficiently lead the medical ‘on-take’.(1) This can lead to delays in patient diagnosis or treatment. Because a single delay can easily burgeon into a lengthy series of multiple delays, this can lead to an associated prolongation of patient stay.(3)

Both confidence and competence in practical procedures can be increased with a procedure bleep system. A dedicated procedure bleep, carried on a rotational basis alerts the bleep holder when a medical procedure is planned. The bleep holder then attends to observe, assist, perform, or teach the relevant procedure.

This scheme shares the opportunities for procedure exposure amongst all trainees and ensures that a good breadth of experience has been gained independent of current placement. Formal evaluation revealed that 95% (19/20) of junior trainees felt more confident and competent as a result of participation. Furthermore, consultants felt this initiative reduced the burden on the medical registrars on-call.

By ensuring our diagnostic and therapeutic interventions are conducted efficiently, we are actively reducing length of hospital stay and improving the standard of healthcare provided.
Republished: Value of biomarkers in osteoarthritis: current status and perspectives
Authors: Lotz M , Martel-Pelletier J , Christiansen C , Brandi M-L , Bruyère O , Chapurlat R , Collette J , Cooper C , Giacovelli G , Kanis J A , Karsdal M A , Kraus V , Lems W F , Meulenbelt I , Pelletier J-P , Raynauld J-P , Reiter-Niesert S , Rizzoli R , Sandell L J , Van Spil W E , Reginster J-Y
Published: February 2014

Osteoarthritis affects the whole joint structure with progressive changes in cartilage, menisci, ligaments and subchondral bone, and synovial inflammation. Biomarkers are being developed to quantify joint remodelling and disease progression. This article was prepared following a working meeting of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis convened to discuss the value of biochemical markers of matrix metabolism in drug development in osteoarthritis. The best candidates are generally molecules or molecular fragments present in cartilage, bone or synovium and may be specific to one type of joint tissue or common to them all. Many currently investigated biomarkers are associated with collagen metabolism in cartilage or bone, or aggrecan metabolism in cartilage. Other biomarkers are related to non-collagenous proteins, inflammation and/or fibrosis. Biomarkers in osteoarthritis can be categorised using the burden of disease, investigative, prognostic, efficacy of intervention, diagnostic and safety classification. There are a number of promising candidates, notably urinary C-terminal telopeptide of collagen type II and serum cartilage oligomeric protein, although none is sufficiently discriminating to differentiate between individual patients and controls (diagnostic) or between patients with different disease severities (burden of disease), predict prognosis in individuals with or without osteoarthritis (prognostic) or perform so consistently that it could function as a surrogate outcome in clinical trials (efficacy of intervention). Future avenues for research include exploration of underlying mechanisms of disease and development of new biomarkers; technological development; the ‘omics’ (genomics, metabolomics, proteomics and lipidomics); design of aggregate scores combining a panel of biomarkers and/or imaging markers into single diagnostic algorithms; and investigation into the relationship between biomarkers and prognosis.
AN ENERGY-EFFICIENT DEADLINE-BASED DATA GATHERING ALGORITHM IN HIERARCHICAL WSN WITH MOBILE SINK
Authors: TASHTARIAN FARZAD , MOGHADDAM MOHAMMAD HOSSEIN YAGHMAEE , EFFATI SOHRAB
Published: February 2014

Remarkable lifetime improvement has been revealed by controlling sink movement in Wireless Sensor Networks (WSNs). This paper proposes a framework for deadline-based and constant bit rate applications to maximize the lifetime of WSN. By dividing all sensor nodes into clusters, a Mini Data Collector (MDC) node which is responsible for data collection, is selected in each cluster. Our proposed algorithm determines a trajectory for the mobile sink to harvest data from MDCs. Indeed, the trajectory is specified according to the virtual Harvesting-Points (HPs) and the prescribed deadline. Proposing a Mixed Integer Linear Programming (MILP) analytical model to maximize the lifetime of WSN in deadline-based applications is the novelty of this paper. Comprehensive investigation on proposed algorithm parameters has been accomplished in simulation section and the superiority of the proposed algorithm to the stationary sink scheme and predefined trajectory algorithms has been revealed.
Age and sex differences in vascular responsiveness in healthy and trauma patients: contribution of estrogen receptor-mediated Rho kinase and PKC pathways
Authors: Li Tao , Xiao Xudong , Zhang Jie , Zhu Yu , Hu Yi , Zang Jiatao , Lu Kaizhi , Yang Tiande , Ge Hengjiang , Peng Xiaoyong , Lan Dan , Liu Liangming
Published: February 2014

Several medical conditions exhibit age- and sex-based differences. Whether or not traumatic shock exhibits such differences with regard to vascular responsiveness is not clear. In a cohort of 177 healthy subjects and 842 trauma patients (21–82 years) as well as different ages (4, 8, 10, 14, 18, and 24 wk; 1 and 1.5 years) and sexes of Sprague-Dawley normal and traumatic shock rats, the age- and sex-based differences of vascular responsiveness and the underlying mechanisms were investigated. Middle-aged and young women as well as female rats of reproductive age had higher vascular responsiveness in the normal condition and a lower decrease in vascular responsiveness after traumatic shock than older men and male rats of identical age. Exogenous supplementation of 17β-estrdiol increased vascular reactivity in both male and femal rats of 8–24 wk and preserved vascular responsiveness in rats following traumatic shock. No effect was observed in rats 1 to 1.5 years. These protective effects of estrogen were closely related to G protein-coupled receptor (GPR)30, estrogen receptor-mediated Rho kinase, and PKC pathway activation. Vascular responsiveness exhibits age- and sex-based differences in healthy subjects and trauma patients. Estrogen and its receptor (GPR30) mediated activation of Rho kinase and PKC using genomic and nongenomic mechanisms to elicit protective effects in vascular responsiveness. This finding is important for the personalized treatment for several age- and sex-related diseases involving estrogen.
Interleukin-18 mediates interleukin-1-induced cardiac dysfunction
Authors: Toldo Stefano , Mezzaroma Eleonora , O'Brien Laura , Marchetti Carlo , Seropian Ignacio M. , Voelkel Norbert F. , Van Tassell Benjamin W. , Dinarello Charles A. , Abbate Antonio
Published: February 2014

Patients with heart failure (HF) have enhanced systemic IL-1 activity, and, in the experimental mouse model, IL-1 induces left ventricular (LV) systolic dysfunction. Whether the effects of IL-1 are direct or mediated by an inducible cytokine, such as IL-18, is unknown. Recombinant human IL-18-binding protein (IL-18BP) or an IL-18-blocking antibody (IL-18AB) was used to neutralize endogenous IL-18 after challenge with the plasma of patients with HF or with recombinant murine IL-1β in adult male mice. Plasma levels of IL-18 and IL-6 (a key mediator of IL-1-induced systemic effects) and LV fractional shortening were measured in mice sedated with pentobarbital sodium (30–50 mg/kg). Mice with genetic deletion of IL-18 or IL-18 receptors were compared with matching wild-type mice. A group of mice received murine IL-18 to evaluate the effects on LV fractional shortening. Plasma from HF patients and IL-1β induced LV systolic dysfunction that was prevented by pretreatment with IL-18AB or IL-18BP. IL-1β failed to induce LV systolic dysfunction in mice with genetic deletion of IL-18 signaling. IL-1β induced a significant increase in plasma IL-18 and IL-6 levels. Genetic or pharmacological inhibition of IL-18 signaling failed to block the induction of IL-6 by IL-1β. In conclusion, IL-1 induces a release of active IL-18 in the mouse that mediates the LV systolic dysfunction but not the induction of IL-6. IL-18 blockade may therefore represent a novel and more targeted therapeutic approach to treat HF.
Aerobic exercise acutely prevents the endothelial dysfunction induced by mental stress among subjects with metabolic syndrome: the role of shear rate
Authors: Sales Allan R. K. , Fernandes Igor A. , Rocha Natália G. , Costa Lucas S. , Rocha Helena N. M. , Mattos João D. M. , Vianna Lauro C. , Silva Bruno M. , Nóbrega Antonio C. L.
Published: February 2014

Mental stress induces transient endothelial dysfunction, which is an important finding for subjects at cardiometabolic risk. Thus, we tested whether aerobic exercise prevents this dysfunction among subjects with metabolic syndrome (MetS) and whether an increase in shear rate during exercise plays a role in this phenomenon. Subjects with MetS participated in two protocols. In protocol 1 ( n = 16), endothelial function was assessed using brachial artery flow-mediated dilation (FMD). Subjects then underwent a mental stress test followed by either 40 min of leg cycling or rest across two randomized sessions. FMD was assessed again at 30 and 60 min after exercise or rest, with a second mental stress test in between. Mental stress reduced FMD at 30 and 60 min after the rest session (baseline: 7.7 ± 0.4%, 30 min: 5.4 ± 0.5%, and 60 min: 3.9 ± 0.5%, P < 0.05 vs. baseline), whereas exercise prevented this reduction (baseline: 7.5 ± 0.4%, 30 min: 7.2 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline). Protocol 2 ( n = 5) was similar to protocol 1 except that the first period of mental stress was followed by either exercise in which the brachial artery shear rate was attenuated via forearm cuff inflation or exercise without a cuff. Noncuffed exercise prevented the reduction in FMD (baseline: 7.5 ± 0.7%, 30 min: 7.0 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline), whereas cuffed exercise failed to prevent this reduction (baseline: 7.5 ± 0.6%, 30 min: 5.4 ± 0.8%, and 60 min: 4.1 ± 0.9%, P < 0.05 vs. baseline). In conclusion, exercise prevented mental stress-induced endothelial dysfunction among subjects with MetS, and an increase in shear rate during exercise mediated this effect.
Albumin modulates S1P delivery from red blood cells in perfused microvessels: mechanism of the protein effect
Authors: Adamson R. H. , Clark J. F. , Radeva M. , Kheirolomoom A. , Ferrara K. W. , Curry F. E.
Published: February 2014

Removal of plasma proteins from perfusates increases vascular permeability. The common interpretation of the action of albumin is that it forms part of the permeability barrier by electrostatic binding to the endothelial glycocalyx. We tested the alternate hypothesis that removal of perfusate albumin in rat venular microvessels decreased the availability of sphingosine-1-phosphate (S1P), which is normally carried in plasma bound to albumin and lipoproteins and is required to maintain stable baseline endothelial barriers ( Am J Physiol Heart Circ Physiol 303: H825–H834, 2012). Red blood cells (RBCs) are a primary source of S1P in the normal circulation. We compared apparent albumin permeability coefficients [solute permeability ( Ps)] measured using perfusates containing albumin (10 mg/ml, control) and conditioned by 20-min exposure to rat RBCs with Pswhen test perfusates were in RBC-conditioned protein-free Ringer solution. The control perfusate S1P concentration (439 ± 46 nM) was near the normal plasma value at 37°C and established a stable baseline Ps(0.9 ± 0.4 × 10−6cm/s). Ringer solution perfusate contained 52 ± 8 nM S1P and increased Psmore than 10-fold (16.1 ± 3.9 × 10−6cm/s). Consistent with albumin-dependent transport of S1P from RBCs, S1P concentrations in RBC-conditioned solutions decreased as albumin concentration, hematocrit, and temperature decreased. Protein-free Ringer solution perfusates that used liposomes instead of RBCs as flow markers failed to maintain normal permeability, reproducing the “albumin effect” in these mammalian microvessels. We conclude that the albumin effect depends on the action of albumin to facilitate the release and transport of S1P from RBCs that normally provide a significant amount of S1P to the endothelium.