bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibriophages Differentially Influence Biofilm Formation by Vibrio anguillarum Strains
Authors: Tan Demeng , Dahl Amalie , Middelboe Mathias
Published: April 2015

Vibrio anguillarumis an important pathogen in marine aquaculture, responsible for vibriosis. Bacteriophages can potentially be used to control bacterial pathogens; however, successful application of phages requires a detailed understanding of phage-host interactions under both free-living and surface-associated growth conditions. In this study, we exploredin vitrophage-host interactions in two different strains ofV. anguillarum(BA35 and PF430-3) during growth in microcolonies, biofilms, and free-living cells. Two vibriophages, ΦH20 (Siphoviridae) and KVP40 (Myoviridae), had completely different effects on the biofilm development. Addition of phage ΦH20 to strain BA35 showed efficient control of biofilm formation and density of free-living cells. The interactions between BA35 and ΦH20 were thus characterized by a strong phage control of the phage-sensitive population and subsequent selection for phage-resistant mutants. Addition of phage KVP40 to strain PF430-3 resulted in increased biofilm development, especially during the early stage. Subsequent experiments in liquid cultures showed that addition of phage KVP40 stimulated the aggregation of host cells, which protected the cells against phage infection. By the formation of biofilms, strain PF430-3 created spatial refuges that protected the host from phage infection and allowed coexistence between phage-sensitive cells and lytic phage KVP40. Together, the results demonstrate highly variable phage protection mechanisms in two closely relatedV. anguillarumstrains, thus emphasizing the challenges of using phages to control vibriosis in aquaculture and adding to the complex roles of phages as drivers of prokaryotic diversity and population dynamics.
Extraintestinal Pathogenic and Antimicrobial-Resistant Escherichia coli Contamination of 56 Public Restrooms in the Greater Minneapolis-St. Paul Metropolitan Area
Authors: Mohamed Muhanad , Owens Kris , Gajewski Abby , Clabots Connie , Johnston Brian , Thuras Paul , Kuskowski Michael A. , Johnson James R.
Published: April 2015

How extraintestinal pathogenic
Escherichia coli
(ExPEC) and antimicrobial-resistant
E. coli
disseminate through the population is undefined. We studied public restrooms for contamination with
E. coli
and ExPEC in relation to source and extensively characterized the
E. coli
isolates. For this, we cultured 1,120 environmental samples from 56 public restrooms in 33 establishments (obtained from 10 cities in the greater Minneapolis-St. Paul, MN, metropolitan area in 2003) for
E. coli
and compared ecological data with culture results. Isolates underwent virulence genotyping, phylotyping, clonal typing, pulsed-field gel electrophoresis (PFGE), and disk diffusion antimicrobial susceptibility testing. Overall, 168 samples (15% from 89% of restrooms) fluoresced, indicating presumptive
E. coli
: 25 samples (2.2% from 32% of restrooms) yielded
E. coli
isolates, and 10 samples (0.9% from 16% of restrooms) contained ExPEC. Restroom category and cleanliness level significantly predicted only fluorescence, gender predicted fluorescence and
E. coli
, and feces-like material and toilet-associated sites predicted all three endpoints. Of the 25
E. coli
isolates, 7 (28%) were from phylogenetic group B2(virulence-associated), and 8 (32%) were ExPEC. ExPEC isolates more commonly represented group B2 (50% versus 18%) and had significantly higher virulence gene scores than non-ExPEC isolates. Six isolates (24%) exhibited ≥3-class antibiotic resistance, 10 (40%) represented classic human-associated sequence types, and one closely resembled reference human clinical isolates by pulsed-field gel electrophoresis. Thus,
E. coli
, ExPEC, and antimicrobial-resistant
E. coli
sporadically contaminate public restrooms, in ways corresponding with restroom characteristics and within-restroom sites. Such restroom-source
E. coli
strains likely reflect human fecal contamination, may pose a health threat, and may contribute to population-wide dissemination of such strains.
VirR-Mediated Resistance of Listeria monocytogenes against Food Antimicrobials and Cross-Protection Induced by Exposure to Organic Acid Salts
Authors: Kang Jihun , Wiedmann Martin , Boor Kathryn J. , Bergholz Teresa M.
Published: April 2015

Formulations of ready-to-eat (RTE) foods with antimicrobial compounds constitute an important safety measure against foodborne pathogens such as
Listeria monocytogenes
. While the efficacy of many commercially available antimicrobial compounds has been demonstrated in a variety of foods, the current understanding of the resistance mechanisms employed by
L. monocytogenes
to counteract these stresses is limited. In this study, we screened in-frame deletion mutants of two-component system response regulators associated with the cell envelope stress response for increased sensitivity to commercially available antimicrobial compounds (nisin, lauric arginate, ε-polylysine, and chitosan). A
virR
deletion mutant showed increased sensitivity to all antimicrobials and significantly greater loss of membrane integrity when exposed to nisin, lauric arginate, or ε-polylysine (
P
< 0.05). The VirR-regulated operon,
dltABCD
, was shown to be the key contributor to resistance against these antimicrobial compounds, whereas another VirR-regulated gene,
mprF
, displayed an antimicrobial-specific contribution to resistance. An experiment with a β-glucuronidase (GUS) reporter fusion with the
dlt
promoter indicated that nisin does not specifically induce VirR-dependent upregulation of
dltABCD
. Lastly, prior exposure of
L. monocytogenes
parent strain H7858 and the Δ
virR
mutant to 2% potassium lactate enhanced subsequent resistance against nisin and ε-polylysine (
P
< 0.05). These data demonstrate that VirRS-mediated regulation of
dltABCD
is the major resistance mechanism used by
L. monocytogenes
against cell envelope-damaging food antimicrobials. Further, the potential for cross-protection induced by other food-related stresses (e.g., organic acids) needs to be considered when applying these novel food antimicrobials as a hurdle strategy for RTE foods.
Thermophilic Coenzyme B
12
-Dependent Acyl Coenzyme A (CoA) Mutase from Kyrpidia tusciae DSM 2912 Preferentially Catalyzes Isomerization of (
R
)-3-Hydroxybutyryl-CoA and 2-Hydroxyisobutyryl-CoA
Authors: Weichler Maria-Teresa , Kurteva-Yaneva Nadya , Przybylski Denise , Schuster Judith , Müller Roland H. , Harms Hauke , Rohwerder Thore
Published: April 2015

The recent discovery of a coenzyme B
12
-dependent acyl-coenzyme A (acyl-CoA) mutase isomerizing 3-hydroxybutyryl- and 2-hydroxyisobutyryl-CoA in the mesophilic bacterium
Aquincola tertiaricarbonis
L108 (N. Yaneva, J. Schuster, F. Schäfer, V. Lede, D. Przybylski, T. Paproth, H. Harms, R. H. Müller, and T. Rohwerder, J Biol Chem 287:15502–15511, 2012,
http://dx.doi.org/10.1074/jbc.M111.314690
) could pave the way for a complete biosynthesis route to the building block chemical 2-hydroxyisobutyric acid from renewable carbon. However, the enzyme catalyzes only the conversion of the stereoisomer (
S
)-3-hydroxybutyryl-CoA at reasonable rates, which seriously hampers an efficient combination of mutase and well-established bacterial poly-(
R
)-3-hydroxybutyrate (PHB) overflow metabolism. Here, we characterize a new 2-hydroxyisobutyryl-CoA mutase found in the thermophilic knallgas bacterium
Kyrpidia tusciae
DSM 2912. Reconstituted mutase subunits revealed highest activity at 55°C. Surprisingly, already at 30°C, isomerization of (
R
)-3-hydroxybutyryl-CoA was about 7,000 times more efficient than with the mutase from strain L108. The most striking structural difference between the two mutases, likely determining stereospecificity, is a replacement of active-site residue Asp found in strain L108 at position 117 with Val in the enzyme from strain DSM 2912, resulting in a reversed polarity at this binding site. Overall sequence comparison indicates that both enzymes descended from different prokaryotic thermophilic methylmalonyl-CoA mutases. Concomitant expression of PHB enzymes delivering (
R
)-3-hydroxybutyryl-CoA (beta-ketothiolase PhaA and acetoacetyl-CoA reductase PhaB from
Cupriavidus necator
) with the new mutase in
Escherichia coli
JM109 and BL21 strains incubated on gluconic acid at 37°C led to the production of 2-hydroxyisobutyric acid at maximal titers of 0.7 mM. Measures to improve production in
E. coli
, such as coexpression of the chaperone MeaH and repression of thioesterase II, are discussed.
Efficient Genome Editing in Clostridium cellulolyticum via CRISPR-Cas9 Nickase
Authors: Xu Tao , Li Yongchao , Shi Zhou , Hemme Christopher L. , Li Yuan , Zhu Yonghua , Van Nostrand Joy D. , He Zhili , Zhou Jizhong
Published: April 2015

The CRISPR-Cas9 system is a powerful and revolutionary genome-editing tool for eukaryotic genomes, but its use in bacterial genomes is very limited. Here, we investigated the use of the
Streptococcus pyogenes
CRISPR-Cas9 system in editing the genome of
Clostridium cellulolyticum
, a model microorganism for bioenergy research. Wild-type Cas9-induced double-strand breaks were lethal to
C. cellulolyticum
due to the minimal expression of nonhomologous end joining (NHEJ) components in this strain. To circumvent this lethality, Cas9 nickase was applied to develop a single-nick-triggered homologous recombination strategy, which allows precise one-step editing at intended genomic loci by transforming a single vector. This strategy has a high editing efficiency (>95%) even using short homologous arms (0.2 kb), is able to deliver foreign genes into the genome in a single step without a marker, enables precise editing even at two very similar target sites differing by two bases preceding the seed region, and has a very high target site density (median interval distance of 9 bp and 95.7% gene coverage in
C. cellulolyticum
). Together, these results establish a simple and robust methodology for genome editing in NHEJ-ineffective prokaryotes.
Combining Lactic Acid Spray with Near-Infrared Radiation Heating To Inactivate Salmonella enterica Serovar Enteritidis on Almond and Pine Nut Kernels
Authors: Ha Jae-Won , Kang Dong-Hyun
Published: April 2015

The aim of this study was to investigate the efficacy of near-infrared radiation (NIR) heating combined with lactic acid (LA) sprays for inactivating
Salmonella enterica
serovar Enteritidis on almond and pine nut kernels and to elucidate the mechanisms of the lethal effect of the NIR-LA combined treatment. Also, the effect of the combination treatment on product quality was determined. Separately prepared
S
. Enteritidis phage type (PT) 30 and non-PT 30
S
. Enteritidis cocktails were inoculated onto almond and pine nut kernels, respectively, followed by treatments with NIR or 2% LA spray alone, NIR with distilled water spray (NIR-DW), and NIR with 2% LA spray (NIR-LA). Although surface temperatures of nuts treated with NIR were higher than those subjected to NIR-DW or NIR-LA treatment, more
S
. Enteritidis survived after NIR treatment alone. The effectiveness of NIR-DW and NIR-LA was similar, but significantly more sublethally injured cells were recovered from NIR-DW-treated samples. We confirmed that the enhanced bactericidal effect of the NIR-LA combination may not be attributable to cell membrane damage
per se
. NIR heat treatment might allow
S
. Enteritidis cells to become permeable to applied LA solution. The NIR-LA treatment (5 min) did not significantly (
P
> 0.05) cause changes in the lipid peroxidation parameters, total phenolic contents, color values, moisture contents, and sensory attributes of nut kernels. Given the results of the present study, NIR-LA treatment may be a potential intervention for controlling food-borne pathogens on nut kernel products.
Patterns and Determinants of Halophilic Archaea (Class Halobacteria) Diversity in Tunisian Endorheic Salt Lakes and Sebkhet Systems
Authors: Najjari Afef , Elshahed Mostafa S. , Cherif Ameur , Youssef Noha H.
Published: April 2015

We examined the diversity and community structure of members of the halophilic
Archaea
(class
Halobacteria
) in samples from central and southern Tunisian endorheic salt lakes and sebkhet (also known as sebkha) systems using targeted 16S rRNA gene diversity survey and quantitative PCR (qPCR) approaches. Twenty-three different samples from four distinct locations exhibiting a wide range of salinities (2% to 37%) and physical characteristics (water, salt crust, sediment, and biofilm) were examined. A total of 4,759 operational taxonomic units at the 0.03 (species-level) cutoff (OTU
0.03
s) belonging to 45 currently recognized genera were identified, with 8 to 43 genera (average, 30) identified per sample. In spite of the large number of genera detected per sample, only a limited number (i.e., 2 to 16) usually constituted the majority (≥80%) of encountered sequences.
Halobacteria
diversity showed a strong negative correlation to salinity (Pearson correlation coefficient = −0.92), and community structure analysis identified salinity, rather than the location or physical characteristics of the sample, as the most important factor shaping the
Halobacteria
community structure. The relative abundance of genera capable of biosynthesis of the compatible solute(s) trehalose or 2-sulfotrehalose decreased with increasing salinities (Pearson correlation coefficient = −0.80). Indeed, qPCR analysis demonstrated that the
Halobacteria
otsB
(trehalose-6-phosphatase)/16S rRNA gene ratio decreases with increasing salinities (Pearson correlation coefficient = −0.87). The results highlight patterns and determinants of
Halobacteria
diversity at a previously unexplored ecosystem and indicate that genera lacking trehalose biosynthetic capabilities are more adapted to growth in and colonization of hypersaline (>25% salt) ecosystems than trehalose producers.
Changes in MMP-9 and TIMP-1 Concentrations in Cerebrospinal Fluid after 1 Week of Treatment of Childhood Bacterial Meningitis
Authors: Roine Irmeli , Pelkonen Tuula , Lauhio Anneli , Lappalainen Maija , Cruzeiro Manuel Leite , Bernardino Luis , Tervahartiala Taina , Sorsa Timo , Peltola Heikki
Published: April 2015

We explored the changes of the initially highly upgraded cerebrospinal fluid matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of MMP 1 (TIMP-1) response during recovery of childhood bacterial meningitis and their association with outcome. The sizes of these changes varied substantially, but a steeper decrease in the MMP-9 and an increase of the TIMP-1 concentrations augured a better outcome.
Equine and Canine Influenza H3N8 Viruses Show Minimal Biological Differences Despite Phylogenetic Divergence
Authors: Feng Kurtis H. , Gonzalez Gaelle , Deng Lingquan , Yu Hai , Tse Victor L. , Huang Lu , Huang Kai , Wasik Brian R. , Zhou Bin , Wentworth David E. , Holmes Edward C. , Chen Xi , Varki Ajit , Murcia Pablo R. , Parrish Colin R.
Published: April 2015

The A/H3N8 canine influenza virus (CIV) emerged from A/H3N8 equine influenza virus (EIV) around the year 2000 through the transfer of a single virus from horses to dogs. We defined and compared the biological properties of EIV and CIV by examining their genetic variation, infection, and growth in different cell cultures, receptor specificity, hemagglutinin (HA) cleavage, and infection and growth in horse and dog tracheal explant cultures. Comparison of sequences of viruses from horses and dogs revealed mutations that may be linked to host adaptation and tropism. We prepared infectious clones of representative EIV and CIV strains that were similar to the consensus sequences of viruses from each host. The rescued viruses, including HA and neuraminidase (NA) double reassortants, exhibited similar degrees of long-term growth in MDCK cells. Different host cells showed various levels of susceptibility to infection, but no differences in infectivity were seen when comparing viruses. All viruses preferred α2-3- over α2-6-linked sialic acids for infections, and glycan microarray analysis showed that EIV and CIV HA-Fc fusion proteins bound only to α2-3-linked sialic acids. Cleavage assays showed that EIV and CIV HA proteins required trypsin for efficient cleavage, and no differences in cleavage efficiency were seen. Inoculation of the viruses into tracheal explants revealed similar levels of infection and replication by each virus in dog trachea, although EIV was more infectious in horse trachea than CIV.

IMPORTANCE
Influenza A viruses can cross species barriers and cause severe disease in their new hosts. Infections with highly pathogenic avian H5N1 virus and, more recently, avian H7N9 virus have resulted in high rates of lethality in humans. Unfortunately, our current understanding of how influenza viruses jump species barriers is limited. Our aim was to provide an overview and biological characterization of H3N8 equine and canine influenza viruses using various experimental approaches, since the canine virus emerged from horses approximately 15 years ago. We showed that although there were numerous genetic differences between the equine and canine viruses, this variation did not result in dramatic biological differences between the viruses from the two hosts, and the viruses appeared phenotypically equivalent in most assays we conducted. These findings suggest that the cross-species transmission and adaptation of influenza viruses may be mediated by subtle changes in virus biology.
Fluorescence-Activated Cell Sorting-Based Analysis Reveals an Asymmetric Induction of Interferon-Stimulated Genes in Response to Seasonal Influenza A Virus
Authors: von Recum-Knepper Jessica , Sadewasser Anne , Weinheimer Viola K. , Wolff Thorsten
Published: April 2015

Influenza A virus (IAV) infection provokes an antiviral response involving the expression of type I and III interferons (IFN) and IFN-stimulated genes (ISGs) in infected cell cultures. However, the spatiotemporal dynamics of the IFN reaction are incompletely understood, as previous studies investigated mainly the population responses of virus-infected cultures, although substantial cell-to-cell variability has been documented. We devised a fluorescence-activated cell sorting-based assay to simultaneously quantify expression of viral antigens and ISGs, such as ISG15, MxA, and IFIT1, in IAV-infected cell cultures at the single-cell level. This approach revealed that seasonal IAV triggers an unexpected asymmetric response, as the major cell populations expressed either viral antigen or ISG, but rarely both. Further investigations identified a role of the viral NS1 protein in blocking ISG expression in infected cells, which surprisingly did not reduce paracrine IFN signaling to noninfected cells. Interestingly, viral ISG control was impaired in cultures infected with avian-origin IAV, including the H7N9 virus from eastern China. This phenotype was traced back to polymorphic NS1 amino acids known to be important for stable binding of the polyadenylation factor CPSF30 and concomitant suppression of host cell gene expression. Most significantly, mutation of two amino acids within the CPSF30 attachment site of NS1 from seasonal IAV diminished the strict control of ISG expression in infected cells and substantially attenuated virus replication. In conclusion, our approach revealed an asymmetric, NS1-dependent ISG induction in cultures infected with seasonal IAV, which appears to be essential for efficient virus propagation.

IMPORTANCE
Interferons are expressed by infected cells in response to IAV infection and play important roles in the antiviral immune response by inducing hundreds of interferon-stimulated genes (ISGs). Unlike many previous studies, we investigated the ISG response at the single-cell level, enabling novel insights into this virus-host interaction. Hence, cell cultures infected with seasonal IAV displayed an asymmetric ISG induction that was confined almost exclusively to noninfected cells. In comparison, ISG expression was observed in larger cell populations infected with avian-origin IAV, suggesting a more resolute antiviral response to these strains. Strict control of ISG expression by seasonal IAV was explained by the binding of the viral NS1 protein to the polyadenylation factor CPSF30, which reduces host cell gene expression. Mutational disruption of CPSF30 binding within NS1 concomitantly attenuated ISG control and replication of seasonal IAV, illustrating the importance of maintaining an asymmetric ISG response for efficient virus propagation.
Clinical outcomes of patients with acute minor stroke receiving rescue IA therapy following early neurological deterioration
Authors: Kim Joon-Tae , Heo Suk-Hee , Yoon Woong , Choi Kang-Ho , Park Man-Seok , Saver Jeffrey L , Cho Ki-Hyun
Published: April 2015

Background

Patients presenting with minor ischemic stroke frequently have early neurological deterioration (END) and poor final outcome. The optimal management of patients with END has not been determined.

Objective

To investigate rescue IA therapy (IAT) when patients with acute minor ischemic stroke develop END.

Methods

This was a retrospective study of consecutively registered patients with acute minor stroke and END. ‘END’ was defined as an increase in National Institutes of Health Stroke Scale (NIHSS) scores by 1 or more points (or development of new neurological symptoms) and ‘ΔEND−NIHSS’ was defined as numerical difference between NIHSS scores at the time of END and before END. Rescue IAT following END was adjusted for the covariates to evaluate the association between IAT and favorable outcome at 3 months.

Results

Among 982 patients with acute minor ischemic stroke, END occurred in 232 (23.6%). Of the 209 patients with END with full data available, 87 (41.6%) had favorable outcomes at 3 months. Rescue IAT following END was performed in 28 (13.4%). Favorable 3-month outcomes were seen in 50% of patients undergoing rescue IAT, including 8/19 (42.1%) undergoing rescue IAT beyond 8 h. By multivariate logistic regression analysis, rescue IAT following END was independently associated with favorable outcome at 3 months (OR=10.9; 95% CI 3.06 to 38.84; p<0.001).

Conclusions

The results suggest that rescue IAT may be safe and effective when END occurs in selected patients with acute minor ischemic stroke. Further prospective and randomized studies are needed to confirm our results.
The 7-year teesside experience of primary prevention ICD indications following primary PCI (PPCI) and the potential impact of a change in NICE guidance
Authors: Phan Thanh Trung , Khan Saima , Mahmood Muhammad Muzaffar , Mani Sudha , Wadehra Vineet , de Belder Mark , Thornley Andrew , James Simon , Linker Nicholas J , Turley Andrew J
Published: April 2015

Introduction

The recovery of LV function in patients with severe LV impairment in the acute phase following primary percutaneous coronary intervention (PPCI) is not well established. The indication for a primary prevention ICD post-STEMI is dependent on which screening guidance, NICE or ESC, is followed. The potential impact of the new NICE guidance is estimated.

Methods

We performed a retrospective analysis of all patients presenting with a STEMI over a 7-year period (2005–2012) treated with PPCI to determine in-hospital mortality, LV function at index presentation, at 3 months and the predicted primary prevention ICD implantation rate using NICE (TA095) and ESC 2006 guidelines. Predicted implant rates using the new NICE guidance (TA314) and actual implantation rates were also assessed.

Results

3902 patients with a mean age of 65±13 years underwent PPCI. Of those patients surviving until discharge, 332 (10%) had LVEF ≤35%. 254 of 332 patients (76%) with a severely impaired ventricle were followed up at participating centres. 210 of 254 (83%) patients had a repeat echocardiogram within 3 months post-MI; among these patients, 89 (42%) remained to have LVEF ≤35%. The number of patients fulfilling NICE and ESC criteria for primary prevention ICD implantation was 14 (16%) and 84 (94%), respectively. The actual number of patients receiving an ICD was 17 (19%). The number of patients fulfilling the new NICE (TA314) guidance was 84 (94%).

Conclusions

A small proportion of patients with STEMIs undergoing PPCI have a severely impaired LV systolic function. A large proportion of these patients will have improved LV systolic function at 3 months. There is a five-fold difference in the predicted ICD implantation rates depending on which guidance is followed—NICE versus ESC. The potential impact of the new NICE (TA314) guidance on ICD implantation will be a significant increase in ICD implantation rates.
Supersymmetry breaking in a warped geometry after the first run of the LHC
Authors: Gherghetta Tony
Published: April 2015

The first run of the LHC has been tremendously successful, having discovered the Higgs boson as well as having set stringent limits on superpartner masses. This has severely constrained supersymmetric models. A consistent scenario based on LHC data suggests that the third generation sfermions, Higgsinos and the gluino must be light while the first two generation sfermions are heavy. Furthermore, an extra contribution to the Higgs quartic coupling is needed to explain the 126 GeV Higgs mass. Interestingly this spectrum can naturally arise from supersymmetry breaking in a warped geometry where the sfermion spectrum is related to the fermion mass hierarchy. Various possible scenarios are reviewed and compared with the data from the first run at the LHC.
Limits on stringy signals at the LHC
Authors: Lüst Dieter , Taylor Tomasz R.
Published: April 2015

We explain what features of string theory can be tested at the LHC. We review the present bounds on the string mass and on extra gauge bosons as well as the prospects for the upcoming experiments.
Constraints on extra dimensions from the ATLAS experiment at the LHC
Authors: Ledroit-Guillon Fabienne
Published: April 2015

The quest for hints about the existence of extra dimensions has recently made tremendous progress with the analysis of the data registered during the first run of the LHC, at center-of-mass energies of 7 TeV and 8 TeV. While we are awaiting the LHC run at nominal energy, it is a good time to review the results and constraints already obtained in a large variety of scenarios and signatures.
Thermodynamical description of the ghost dark energy model
Authors: Honarvaryan M. , Sheykhi A. , Moradpour H.
Published: April 2015

In this paper, we point out thermodynamical description of ghost dark energy (GDE) and its generalization to the early universe. Thereinafter, we find expressions for the entropy changes of these dark energy (DE) candidates. In addition, considering thermal fluctuations, thermodynamics of the DE component interacting with a dark matter (DM) sector is addressed. We will also find the effects of considering the coincidence problem on the mutual interaction between the dark sectors, and thus the equation of state parameter of DE. Finally, we derive a relation between the mutual interaction of the dark components of the universe, accelerated with the either GDE or its generalization, and the thermodynamic fluctuations.
HISPOLON DIFFERENTIALLY MODULATED THE PRODUCTION OF ANTIGEN-INDUCED T CELL CYTOKINES VIA THE REGULATION OF CELLULAR GLUTATHIONE
Authors: Wang Ping-Yen , Wu Hsin-Ying , Cheng Chiung-Hsiang , Hou Wen-Chi , Jan Tong-Rong
Published: April 2015

Hispolon is an active ingredient contained in the medicinal mushroom Phellinus linteus (PL) that is used in traditional Chinese medicine for various remedies, including lymphatic diseases. Previous studies reported that hispolon exhibited anti-inflammatory activities and suppressed mitogen-induced proliferation of splenic lymphocytes. It remains unclear if hispolon influences antigen-specific immunity. The present study investigated the effects of hispolon on cytokine production by antigen-activated T cells. Ovalbumin (OVA)-primed splenocytes were exposed to hispolon, followed by restimulation with OVA. Cell viability was determined by the AlamarBlue® assay and T cell cytokine production was measured by enzyme linked immunosorbent assay (ELISA). The splenocyte viability and the production of interleukin (IL)-4 were unaffected, whereas the production of interferon (IFN)-γ was significantly suppressed by treatment with hispolon (1–5 μM) in a concentration-dependent manner. The suppressive effect of hispolon on the production of IFN-γ was attenuated in the presence of thiol antioxidants, including N-acetyl-L-cysteine (NAC) and glutathione, whereas the non-thiol antioxidant pyruvate was ineffective. Taken together, these results demonstrated that hispolon induced a differential effect on antigen-induced cytokine production by T cells, in which the T helper 1 (Th1) cytokine IFN-γ was sensitive, whereas the Th2 cytokine IL-4 was unaffected. In addition, the suppressive effect of hispolon on IFN-γ production was associated with the diminishment of intracellular glutathione.
Pre-salt microbialites from the Campos Basin (offshore Brazil): image log facies, facies model and cyclicity in lacustrine carbonates
Authors: Muniz M. C. , Bosence D. W. J.
Published: April 2015

This study uses a borehole image log, supported by limited sidewall-core samples, and conventional wireline logs to erect facies and stratigraphic models for the Aptian pre-salt microbial carbonates (Macabu Formation (Fm)) of the southern Campos Basin, Brazil. This supports the widely held view that these reservoirs are very significant, unusual, partly microbial, and lacustrine in origin. This single-well study penetrates 220 m of microbialite facies from the pre-salt Lagoa Feia Group non-marine carbonates. Continuous borehole images, available sidewall-core data, and gamma-ray and sonic wireline logs are used to identify and characterize borehole image facies. These facies are interpreted to have formed in four lacustrine depositional environments: deep subaqueous, intermediate subaqueous, shallow subaqueous and subaerial. The borehole image facies commonly show shallowing-upward facies trends topped by emergent surfaces. Such trends are interpreted as metre-scale, high-frequency cycles that are grouped into lower order depositional sequences interpreted from the gamma-ray log. A Fischer plot of the high-frequency cycle suggests that the entire Macabu Fm is represented by a decrease in the accommodation space followed by increase in the accommodation space; consistent with this suggestion are trends in δ
18
O values from an adjacent well that indicate an initial trend of increased evaporation followed by increased freshwater inflow (lighter δ
18
O and thicker cycles).
Pyruvate modifies metabolic flux and nutrient sensing during extracorporeal membrane oxygenation in an immature swine model
Authors: Ledee Dolena R. , Kajimoto Masaki , O'Kelly Priddy Colleen M. , Olson Aaron K. , Isern Nancy , Robillard-Frayne Isabelle , Des Rosiers Christine , Portman Michael A.
Published: April 2015

Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support for infants and children with postoperative cardiopulmonary failure. Nutritional support is mandatory during ECMO although specific actions for substrates on the heart have not been delineated. Prior work shows that enhancing pyruvate oxidation promotes successful weaning from ECMO. Accordingly, we tested the hypothesis that prolonged systemic pyruvate supplementation activates pyruvate oxidation in an immature swine model in vivo. Twelve male mixed-breed Yorkshire piglets (age 30–49 days) received systemic infusion of either normal saline (group C) or pyruvate (group P) during the final 6 h of 8 h of ECMO. Over the final hour, piglets received [2-13C] pyruvate, as a reference substrate for oxidation, and [13C6]-l-leucine, as an indicator for amino acid oxidation and protein synthesis. A significant increase in lactate and pyruvate concentrations occurred, along with an increase in the absolute concentration of the citric acid cycle intermediates. An increase in anaplerotic flux through pyruvate carboxylation in group P occurred compared with no change in pyruvate oxidation. Additionally, pyruvate promoted an increase in the phosphorylation state of several nutrient-sensitive enzymes, like AMP-activated protein kinase and acetyl CoA carboxylase, suggesting activation for fatty acid oxidation. Pyruvate also promoted O-GlcNAcylation through the hexosamine biosynthetic pathway. In conclusion, although prolonged pyruvate supplementation did not alter pyruvate oxidation, it did elicit changes in nutrient- and energy-sensitive pathways. Therefore, the observed results support the further study of pyruvate and its downstream effect on cardiac function.
OPC-28326, a selective peripheral vasodilator with angiogenic activity, mitigates postinfarction cardiac remodeling
Authors: Ogino Atsushi , Takemura Genzou , Hashimoto Ayako , Kanamori Hiromitsu , Okada Hideshi , Nakagawa Munehiro , Tsujimoto Akiko , Goto Kazuko , Kawasaki Masanori , Nagashima Kenshi , Miyakoda Goro , Fujiwara Takako , Yabuuchi Youichi , Fujiwara Hisayoshi , Minatoguchi Shinya
Published: April 2015

Although OPC-28326, 4-( N-methyl-2-phenylethylamino)-1-(3,5-dimethyl-4-propionyl-aminobenzoyl) piperidine hydrochloride monohydrate, was developed as a selective peripheral vasodilator with α2-adrenergic antagonist properties, it also reportedly exhibits angiogenic activity in an ischemic leg model. The purpose of this study was to examine the effect of OPC-28326 on the architectural dynamics and function of the infarcted left ventricle during the chronic stage of myocardial infarction. Myocardial infarction was induced in male C3H/He mice, after which the mice were randomly assigned into two groups: a control group receiving a normal diet and an OPC group whose diet contained 0.05% OPC-28326. The survival rate among the mice ( n = 18 in each group) 4 wk postinfarction was significantly greater in the OPC than control group (83 vs. 44%; P < 0.05), and left ventricular remodeling and dysfunction were significantly mitigated. Histologically, infarct wall thickness was significantly greater in the OPC group, due in part to an abundance of nonmyocyte components, including blood vessels and myofibroblasts. Five days postinfarction, Ki-67-positive proliferating cells were more abundant in the granulation tissue in the OPC group, and there were fewer apoptotic cells. These effects were accompanied by activation of myocardial Akt and endothelial nitric oxide synthase. Hypoxia within the infarct issue, assessed using pimonidazole staining, was markedly attenuated in the OPC group. In summary, OPC-28326 increased the nonmyocyte population in infarct tissue by increasing proliferation and reducing apoptosis, thereby altering the tissue dynamics such that wall stress was reduced, which might have contributed to a mitigation of postinfarction cardiac remodeling and dysfunction.
Regulation of myogenic tone and structure of parenchymal arterioles by hypertension and the mineralocorticoid receptor
Authors: Pires Paulo W. , Jackson William F. , Dorrance Anne M.
Published: April 2015

Proper perfusion is vital for maintenance of neuronal homeostasis and brain function. Changes in the function and structure of cerebral parenchymal arterioles (PAs) could impair blood flow regulation and increase the risk of cerebrovascular diseases, including dementia and stroke. Hypertension alters the structure and function of large cerebral arteries, but its effects on PAs remain unknown. We hypothesized that hypertension increases myogenic tone and induces inward remodeling in PAs; we further proposed that antihypertensive therapy or mineralocorticoid receptor (MR) blockade would reverse the effects of hypertension. PAs from 18-wk-old stroke-prone spontaneously hypertensive rats (SHRSP) were isolated and cannulated in a pressure myograph. At 50-mmHg intraluminal pressure, PAs from SHRSP showed higher myogenic tone (%tone: 39.1 ± 1.9 vs. 28.7 ± 2.5%, P < 0.01) and smaller resting luminal diameter (34.7 ± 1.9 vs. 46.2 ± 2.4 μm, P < 0.01) than those from normotensive Wistar-Kyoto rats, through a mechanism that seems to require Ca2+influx through L-type voltage-gated Ca2+channels. PAs from SHRSP showed inward remodeling (luminal diameter at 60 mmHg: 55.2 ± 1.4 vs. 75.7 ± 5.1 μm, P < 0.01) and a paradoxical increase in distensibility and compliance. Treatment of SHRSP for 6 wk with antihypertensive therapy reduced PAs' myogenic tone, increased their resting luminal diameter, and prevented inward remodeling. In contrast, treatment of SHRSP for 6 wk with an MR antagonist did not reduce blood pressure or myogenic tone, but prevented inward remodeling. Thus, while hypertensive remodeling of PAs may involve the MR, myogenic tone seems to be independent of MR activity.
Dynamics of AV coupling during human atrial fibrillation: role of atrial rate
Authors: Masè M. , Marini M. , Disertori M. , Ravelli F.
Published: April 2015

The causal relationship between atrial and ventricular activities during human atrial fibrillation (AF) is poorly understood. This study analyzed the effects of an increase in atrial rate on the link between atrial and ventricular activities during AF. Atrial and ventricular time series were determined in 14 patients during the spontaneous acceleration of the atrial rhythm at AF onset. The dynamic relationship between atrial and ventricular activities was quantified in terms of atrioventricular (AV) coupling by AV synchrogram analysis. The technique identified n: m coupling patterns ( n atrial beats in m ventricular cycles), quantifying their percentage, maximal length, and conduction ratio (= m/ n). Simulations with a difference-equation AV model were performed to correlate the observed dynamics to specific atrial/nodal properties. The atrial rate increase significantly affected AV coupling and ventricular response during AF. The shortening of atrial intervals from 185 ± 32 to 165 ± 24 ms ( P < 0.001) determined transitions toward AV patterns with progressively decreasing m/ n ratios (from conduction ratio = 0.34 ± 0.09 to 0.29 ± 0.08, P < 0.01), lower occurrence (from percentage of coupled beats = 27.1 ± 8.0 to 21.8 ± 6.9%, P < 0.05), and higher instability (from maximal length = 3.9 ± 1.5 to 2.8 ± 0.7 s, P < 0.01). Advanced levels of AV block and coupling instability at higher atrial rates were associated with increased ventricular interval variability (from 123 ± 52 to 133 ± 55 ms, P < 0.05). AV pattern transitions and coupling instability in patients were predicted, assuming the filtering of high-rate irregular atrial beats by the slow recovery of nodal excitability. These results support the role of atrial rate in determining AV coupling and ventricular response and may have implications for rate control in AF.
Increased activity of mitochondrial uncoupling protein 2 improves stress resistance in cultured endothelial cells exposed in vitro to high glucose levels
Authors: Koziel Agnieszka , Sobieraj Izabela , Jarmuszkiewicz Wieslawa
Published: April 2015

The endothelium is relatively independent of the mitochondrial energy supply, but mitochondria-derived ROS may play an important role in the development of many cardiovascular diseases. Energy-dissipating uncoupling proteins (UCPs) mediate free fatty acid-activated, purine nucleotide-inhibited proton conductance (uncoupling) in the inner mitochondrial membrane. We have described a functional characteristic and an antioxidative role for UCP2 in endothelial cells and isolated mitochondria and how this function is altered by long-term growth in high concentrations of glucose. Human umbilical vein endothelial cells (EA.hy926 line) were grown in media with either high (25 mM) or normal (5.5 mM) glucose concentrations. Under nonphosphorylating and phosphorylating conditions, UCP activity was significantly higher in mitochondria isolated from high glucose-treated cells. More pronounced control of the respiratory rate, membrane potential, and ROS by UCP2 was observed in these mitochondria. A greater UCP2-mediated decrease in ROS generation indicates an improved antioxidative role for UCP2 under high glucose conditions. Mitochondrial and nonmitochondrial ROS generations were significantly higher in high glucose-treated cells independent of UCP2 expression. UCP2 gene silencing led to elevated mitochondrial ROS formation and ICAM1 expression, especially in high glucose-cultured cells. UCP2 influenced endothelial cell viability and resistance to oxidative stress. Endothelial cells exposed to high glucose concentrations were significantly more resistant to peroxide. In these cells, the increased activity of UCP2 led to improved stress resistance and protection against acute oxidative stress. Our results indicate that endothelial UCP2 may function as a sensor and negative regulator of mitochondrial ROS production in response to hyperglycemia.
Effect of docosahexaenoic acid monoacylglyceride on systemic hypertension and cardiovascular dysfunction
Authors: Morin Caroline , Rousseau Eric , Blier Pierre U. , Fortin Samuel
Published: April 2015

ω-3 Fatty acid supplementation has been associated with lower blood pressure. Cardiovascular diseases are also known to be linked directly to an increase in ω-6 and a reduction in ω-3 fatty acid levels in blood circulation and tissues. To determine the effect of docosahexaenoic acid monoglycerides (MAG-DHA) on blood pressure, lipid profiles, and vascular remodeling in rats fed a high-fat/high-carbohydrate (HFHC) diet. Studies were performed in male rats subjected to 8 wk of HFHC diet supplemented or not with 3 g/day MAG-DHA. After 8 wk of daily MAG-DHA treatment, rats in the HFHC + MAG-DHA group had lower arterial blood pressure and heart rate compared with the HFHC group. Moreover, MAG-DHA prevented the increase aortic wall thickness, whereas lipid analysis of aortic tissues revealed an increase in DHA/AA ratio correlated with the production of resolvin D2 and D3 metabolites. Histological analysis revealed that MAG-DHA prevented the development of LVH in the HFHC group. Serum lipid profile analysis further showed a decrease in total cholesterol (TC) and LDL, including very low-density lipoprotein (VLDL) and triglyceride (TG) levels, together with an increase in HDL levels after 8 wk of MAG-DHA treatment compared with the HFHC group. Furthermore, daily MAG-DHA treatment resulted in reduced proinflammatory marker levels such as CRP, IL-6, TNFα, and IL-1β. Altogether, these findings revealed that per os administration of MAG-DHA prevents HFHC-diet induced hypertension and LVH in rats.
Sphingosine-1-phosphate receptor 1 agonism attenuates lung ischemia-reperfusion injury
Authors: Stone Matthew L. , Sharma Ashish K. , Zhao Yunge , Charles Eric J. , Huerter Mary E. , Johnston William F. , Kron Irving L. , Lynch Kevin R. , Laubach Victor E.
Published: April 2015

Outcomes for lung transplantation are the worst of any solid organ, and ischemia-reperfusion injury (IRI) limits both short- and long-term outcomes. Presently no therapeutic agents are available to prevent IRI. Sphingosine 1-phosphate (S1P) modulates immune function through binding to a set of G protein-coupled receptors (S1PR1-5). Although S1P has been shown to attenuate lung IRI, the S1P receptors responsible for protection have not been defined. The present study tests the hypothesis that protection from lung IRI is primarily mediated through S1PR1 activation. Mice were treated with either vehicle, FTY720 (a nonselective S1P receptor agonist), or VPC01091 (a selective S1PR1 agonist and S1PR3 antagonist) before left lung IR. Function, vascular permeability, cytokine expression, neutrophil infiltration, and myeloperoxidase levels were measured in lungs. After IR, both FTY720 and VPC01091 significantly improved lung function (reduced pulmonary artery pressure and increased pulmonary compliance) vs. vehicle control. In addition, FTY720 and VPC01091 significantly reduced vascular permeability, expression of proinflammatory cytokines (IL-6, IL-17, IL-12/IL-23 p40, CC chemokine ligand-2, and TNF-α), myeloperoxidase levels, and neutrophil infiltration compared with control. No significant differences were observed between VPC01091 and FTY720 treatment groups. VPC01091 did not significantly affect elevated invariant natural killer T cell infiltration after IR, and administration of an S1PR1 antagonist reversed VPC01091-mediated protection after IR. In conclusion, VPC01091 and FTY720 provide comparable protection from lung injury and dysfunction after IR. These findings suggest that S1P-mediated protection from IRI is mediated by S1PR1 activation, independent of S1PR3, and that selective S1PR1 agonists may provide a novel therapeutic strategy to prevent lung IRI.
Determinants of exercise intolerance in patients with heart failure and reduced or preserved ejection fraction
Authors: Haykowsky Mark J. , Tomczak Corey R. , Scott Jessica M. , Paterson D. Ian , Kitzman Dalane W.
Published: April 2015

This mini-review summarizes the literature regarding the mechanisms of exercise intolerance in patients with heart failure and reduced or preserved ejection fraction (HFREF and HFPEF, respectively). Evidence to date suggests that the reduced peak pulmonary oxygen uptake (pulm V̇o2) in patients with HFREF compared with healthy controls is due to both central (reduced convective O2transport) and peripheral factors (impaired skeletal muscle blood flow, decreased diffusive O2transport coupled with abnormal skeletal morphology, and metabolism). Although central and peripheral impairments also limit peak pulm V̇o2in HFPEF patients compared with healthy controls, emerging data suggest that the latter may play a relatively greater role in limiting exercise performance in these patients. Unlike HFREF, currently there is limited evidence-based therapies that improve exercise capacity in HFPEF patients, therefore future studies are required to determine whether interventions targeted to improve peripheral vascular and skeletal muscle function result in favorable improvements in peak pulm and leg V̇o2and their determinants in HFPEF patients.
Human posterior parietal cortex encodes the movement goal in a pro-/anti-reach task
Authors: Gertz Hanna , Fiehler Katja
Published: April 2015

Previous research on reach planning in humans has implicated a frontoparietal network, including the precuneus (PCu), a putative human homolog of the monkey parietal reach region (PRR), and the dorsal premotor cortex (PMd). Using a pro-/anti-reach task, electrophysiological studies in monkeys have demonstrated that the movement goal rather than the location of the visual cue is encoded in PRR and PMd. However, if only the effector but not the movement goal is specified (underspecified condition), the PRR and PMd have been shown to represent all potential movement goals. In this functional magnetic resonance imaging study, we investigated whether the human PCu and PMd likewise encode the movement goal, and whether these reach-related areas also engage in situations with underspecified compared with specified movement goals. By using a pro-/anti-reach task, we spatially dissociated the location of the visual cue from the location of the movement goal. In the specified conditions, pro- and anti-reaches activated similar parietal and premotor areas. In the PCu contralateral to the moving arm, we found directionally selective activation fixed to the movement goal. In the underspecified conditions, we observed activation in reach-related areas of the posterior parietal cortex, including PCu. However, the activation was substantially weaker in parietal areas and lacking in PMd. Our results suggest that human PCu encodes the movement goal rather than the location of the visual cue if the movement goal is specified and even engages in situations when only the visual cue but not the movement goal is defined.