bluuebunny/crossref_metadata_2025_split huggingface dataset:
The mechanistic bases of the power–time relationship: muscle metabolic responses and relationships to muscle fibre type
Authors: Vanhatalo Anni , Black Matthew I. , DiMenna Fred J. , Blackwell Jamie R. , Schmidt Jakob Friis , Thompson Christopher , Wylie Lee J. , Mohr Magni , Bangsbo Jens , Krustrup Peter , Jones Andrew M. 
Published: March 2016

Key points
The power‐asymptote (critical power; CP) of the hyperbolic power–time relationship for high‐intensity exercise defines a threshold between steady‐state and non‐steady‐state exercise intensities and the curvature constant (W′) indicates a fixed capacity for work >CP that is related to a loss of muscular efficiency.
The present study reports novel evidence on the muscle metabolic underpinnings of CP and W′ during whole‐body exercise and their relationships to muscle fibre type.
We show that the W′ is not correlated with muscle fibre type distribution and that it represents an elevated energy contribution from both oxidative and glycolytic/glycogenolytic metabolism.
We show that there is a positive correlation between CP and highly oxidative type I muscle fibres and that muscle metabolic steady‐state is attainable <CP but not >CP.
Our findings indicate a mechanistic link between the bioenergetic characteristics of muscle fibre types and the power–time relationship for high‐intensity exercise.
AbstractWe hypothesized that: (1) the critical power (CP) will represent a boundary separating steady‐state from non‐steady‐state muscle metabolic responses during whole‐body exercise and (2) that the CP and the curvature constant (W′) of the power–time relationship for high‐intensity exercise will be correlated with type I and type IIx muscle fibre distributions, respectively. Four men and four women performed a 3 min all‐out cycling test for the estimation of CP and constant work rate (CWR) tests slightly >CP until exhaustion (Tlim), slightly <CP for 24 min and until the >CP Tlim isotime to test the first hypothesis. Eleven men performed 3 min all‐out tests and donated muscle biopsies to test the second hypothesis. Below CP, muscle [PCr] [42.6 ± 7.1 vs. 49.4 ± 6.9 mmol (kg d.w.)−1], [La−] [34.8 ± 12.6 vs. 35.5 ± 13.2 mmol (kg d.w.)−1] and pH (7.11 ± 0.08 vs. 7.10 ± 0.11) remained stable between ∼12 and 24 min (P > 0.05 for all), whereas these variables changed with time >CP such that they were greater [[La−] 95.6 ± 14.1 mmol (kg d.w.)−1] and lower [[PCr] 24.2 ± 3.9 mmol (kg d.w.)−1; pH 6.84 ± 0.06] (P < 0.05) at Tlim (740 ± 186 s) than during the <CP trial. The CP (234 ± 53 W) was correlated with muscle type I (r = 0.67, P = 0.025) and inversely correlated with muscle type IIx fibre proportion (r = −0.76, P = 0.01). There was no relationship between W′ (19.4 ± 6.3 kJ) and muscle fibre type. These data indicate a mechanistic link between the bioenergetic characteristics of different muscle fibre types and the power–duration relationship. The CP reflects the bioenergetic characteristics of highly oxidative type I muscle fibres, such that a muscle metabolic steady‐state is attainable below and not above CP.
Single cell transcriptome analysis of mouse carotid body glomus cells
Authors: Zhou Ting , Chien Ming‐Shan , Kaleem Safa , Matsunami Hiroaki 
Published: March 2016

Key points
Carotid body (CB) glomus cells mediate acute oxygen sensing and the initiation of the hypoxic ventilatory response, yet the gene expression profile of these cells is not available.
We demonstrate that the single cell RNA‐Seq method is a powerful tool for identifying highly expressed genes in CB glomus cells.
Our single cell RNA‐Seq results characterized novel CB glomus cell genes, including members of the G protein‐coupled receptor signalling pathway, ion channels and atypical mitochondrial electron transport chain subunits.
A heterologous cell‐based screening identified acetate (which is known to affect CB glomus cell activity) as an agonist for the most highly abundant G protein‐coupled receptor (Olfr78) in CB glomus cells.
These data established the first transcriptome profile of CB glomus cells, highlighting genes with potential implications in CB chemosensory function.
AbstractThe carotid body (CB) is a major arterial chemoreceptor containing glomus cells whose activities are regulated by changes in arterial blood content, including oxygen. Despite significant advancements in the characterization of their physiological properties, our understanding of the underlying molecular machinery and signalling pathway in CB glomus cells is still limited. To overcome this, we employed the single cell RNA­Seq method by performing next‐generation sequencing on single glomus cell­derived cDNAs to eliminate contamination of genes derived from other cell types present in the CB. Using this method, we identified a set of genes abundantly expressed in glomus cells, which contained novel glomus cell‐specific genes. Transcriptome and subsequent in situ hybridization and immunohistochemistry analyses identified abundant G protein‐coupled receptor signalling pathway components and various types of ion channels, as well as members of the hypoxia‐inducible factors pathway. A short‐chain fatty acid olfactory receptor Olfr78, recently implicated in CB function, was the most abundant G protein‐coupled receptor. Two atypical mitochondrial electron transport chain subunits (Ndufa4l2 and Cox4i2) were among the most specifically expressed genes in CB glomus cells, highlighting their potential roles in mitochondria‐mediated oxygen sensing. The wealth of information provided by the present study offers a valuable foundation for identifying molecules functioning in the CB.
Influence of Low-Shear Modeled Microgravity on Heat Resistance, Membrane Fatty Acid Composition, and Heat Stress-Related Gene Expression in Escherichia coli O157:H7 ATCC 35150, ATCC 43889, ATCC 43890, and ATCC 43895
Authors: Kim H. W. , Rhee M. S. 
Published: March 2016

ABSTRACT

We previously showed that modeled microgravity conditions alter the physiological characteristics of
Escherichia coli
O157:H7. To examine how microgravity conditions affect bacterial heat stress responses, D values, membrane fatty acid composition, and heat stress-related gene expression (
clpB
,
dnaK
,
grpE
,
groES
,
htpG
,
htpX
,
ibpB
, and
rpoH
),
E. coli
O157:H7 ATCC 35150, ATCC 43889, ATCC 43890, and ATCC 43895 were cultured under two different conditions: low-shear modeled microgravity (LSMMG, an analog of spaceflight conditions) and normal gravity (NG, Earth-like conditions). When 24-h cultures were heated to 55°C, cells cultured under LSMMG conditions showed reduced survival compared with cells cultured under NG conditions at all time points (
P
< 0.05). D values of all tested strains were lower after LSMMG culture than after NG culture. Fourteen of 37 fatty acids examined were present in the bacterial membrane: nine saturated fatty acids (SFA) and five unsaturated fatty acids (USFA). The USFA/SFA ratio, a measure of membrane fluidity, was higher under LSMMG conditions than under NG conditions. Compared with control cells grown under NG conditions, cells cultured under LSMMG conditions showed downregulation of eight heat stress-related genes (average, −1.9- to −3.7-fold). The results of this study indicate that in a simulated space environment, heat resistance of
E. coli
O157:H7 decreased, and this might be due to the synergistic effects of the increases in membrane fluidity and downregulated relevant heat stress genes.

IMPORTANCE
Microgravity is a major factor that represents the environmental conditions in space. Since infectious diseases are difficult to deal with in a space environment, comprehensive studies on the behavior of pathogenic bacteria under microgravity conditions are warranted. This study reports the changes in heat stress resistance of
E. coli
O157:H7, the severe foodborne pathogen, under conditions that mimic microgravity. The results provide scientific clues for further understanding of the bacterial response under the simulated microgravity conditions. It will contribute not only to the improvement of scientific knowledge in the academic fields but also ultimately to the development of a prevention strategy for bacterial disease in the space environment.
Transcriptional Repression of the VC2105 Protein by Vibrio FadR Suggests that It Is a New Auxiliary Member of the
fad
Regulon
Authors: Gao Rongsui , Lin Jingxia , Zhang Han , Feng Youjun 
Published: March 2016

ABSTRACT

Recently, our group along with others reported that the
Vibrio
FadR regulatory protein is unusual in that, unlike the prototypical
fadR
product of
Escherichia coli
, which has only one ligand-binding site,
Vibrio
FadR has two ligand-binding sites and represents a new mechanism for fatty acid sensing. The promoter region of the
vc2105
gene, encoding a putative thioesterase, was mapped, and a putative FadR-binding site (AA CTG GTA AGA GCA CTT) was proposed. Different versions of the FadR regulatory proteins were prepared and purified to homogeneity. Both electrophoretic mobility shift assay (EMSA) and surface plasmon resonance (SPR) determined the direct interaction of the
vc2105
gene with FadR proteins of various origins. Further, EMSAs illustrated that the addition of long-chain acyl-coenzyme A (CoA) species efficiently dissociates the
vc2105
promoter from the FadR regulator. The expression level of the
Vibrio cholerae vc2105
gene was elevated 2- to 3-fold in a
fadR
null mutant strain, validating that FadR is a repressor for the
vc2105
gene. The β-galactosidase activity of a
vc2105-lacZ
transcriptional fusion was increased over 2-fold upon supplementation of growth medium with oleic acid. Unlike the
fadD
gene, a member of the
Vibrio fad
regulon, the VC2105 protein played no role in bacterial growth and virulence-associated gene expression of
ctxAB
(cholera toxin A/B) and
tcpA
(toxin coregulated pilus A). Given that the transcriptional regulation of
vc2105
fits the criteria for fatty acid degradation (
fad
) genes, we suggested that it is a new member of the
Vibrio fad
regulon.

IMPORTANCE
The
Vibrio
FadR regulator is unusual in that it has two ligand-binding sites. Different versions of the FadR regulatory proteins were prepared and characterized
in vitro
and
in vivo
. An auxiliary
fad
gene (
vc2105
) from
Vibrio
was proposed that encodes a putative thioesterase and has a predicted FadR-binding site (AAC TGG TA A GAG CAC TT). The function of this putative binding site was proved using both EMSA and SPR. Further
in vitro
and
in vivo
experiments revealed that the
Vibrio
FadR is a repressor for the
vc2105
gene. Unlike
fadD
, a member of the
Vibrio fad
regulon, VC2105 played no role in bacterial growth and expression of the two virulence-associated genes (
ctxAB
and
tcpA
). Therefore, since transcriptional regulation of
vc2105
fits the criteria for
fad
genes, it seems likely that
vc2105
acts as a new auxiliary member of the
Vibrio fad
regulon.
Diversity of Clinical and Environmental Isolates of Vibrio cholerae in Natural Transformation and Contact-Dependent Bacterial Killing Indicative of Type VI Secretion System Activity
Authors: Bernardy Eryn E. , Turnsek Maryann A. , Wilson Sarah K. , Tarr Cheryl L. , Hammer Brian K. 
Published: March 2016

ABSTRACT

The bacterial pathogen
Vibrio cholerae
can occupy both the human gut and aquatic reservoirs, where it may colonize chitinous surfaces that induce the expression of factors for three phenotypes: chitin utilization, DNA uptake by natural transformation, and contact-dependent bacterial killing via a type VI secretion system (T6SS). In this study, we surveyed a diverse set of 53 isolates from different geographic locales collected over the past century from human clinical and environmental specimens for each phenotype outlined above. The set included pandemic isolates of serogroup O1, as well as several serogroup O139 and non-O1/non-O139 strains. We found that while chitin utilization was common, only 22.6% of the isolates tested were proficient at chitin-induced natural transformation, suggesting that transformation is expendable. Constitutive contact-dependent killing of
Escherichia coli
prey, which is indicative of a functional T6SS, was rare among clinical isolates (only 4 of 29) but common among environmental isolates (22 of 24). These results bolster the pathoadaptive model in which tight regulation of T6SS-mediated bacterial killing is beneficial in a human host, whereas constitutive killing by environmental isolates may give a competitive advantage in natural settings. Future sequence analysis of this set of diverse isolates may identify previously unknown regulators and structural components for both natural transformation and T6SS.
Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104
Authors: Leekitcharoenphon Pimlapas , Hendriksen Rene S. , Le Hello Simon , Weill François-Xavier , Baggesen Dorte Lau , Jun Se-Ran , Ussery David W. , Lund Ole , Crook Derrick W. , Wilson Daniel J. , Aarestrup Frank M. 
Published: March 2016

ABSTRACT

It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant
Salmonella enterica
serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315
S
. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb
Salmonella
genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate
Salmonella
from pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of
Salmonella
infections.
In Situ
Biomineralization and Particle Deposition Distinctively Mediate Biofilm Susceptibility to Chlorine
Authors: Li Xiaobao , Chopp David L. , Russin William A. , Brannon Paul T. , Parsek Matthew R. , Packman Aaron I. 
Published: March 2016

ABSTRACT

Microbial biofilms and mineral precipitation commonly co-occur in engineered water systems, such as cooling towers and water purification systems, and both decrease process performance. Microbial biofilms are extremely challenging to control and eradicate. We previously showed that
in situ
biomineralization and the precipitation and deposition of abiotic particles occur simultaneously in biofilms under oversaturated conditions. Both processes could potentially alter the essential properties of biofilms, including susceptibility to biocides. However, the specific interactions between mineral formation and biofilm processes remain poorly understood. Here we show that the susceptibility of biofilms to chlorination depends specifically on internal transport processes mediated by biomineralization and the accumulation of abiotic mineral deposits. Using injections of the fluorescent tracer Cy5, we show that
Pseudomonas aeruginosa
biofilms are more permeable to solutes after
in situ
calcite biomineralization and are less permeable after the deposition of abiotically precipitated calcite particles. We further show that biofilms are more susceptible to chlorine killing after biomineralization and less susceptible after particle deposition. Based on these observations, we found a strong correlation between enhanced solute transport and chlorine killing in biofilms, indicating that biomineralization and particle deposition regulate biofilm susceptibility by altering biocide penetration into the biofilm. The distinct effects of
in situ
biomineralization and particle deposition on biocide killing highlight the importance of understanding the mechanisms and patterns of biomineralization and scale formation to achieve successful biofilm control.
Development of Novel Quaternary Ammonium Linkers for Antibody–Drug Conjugates
Authors: Burke Patrick J. , Hamilton Joseph Z. , Pires Thomas A. , Setter Jocelyn R. , Hunter Joshua H. , Cochran Julia H. , Waight Andrew B. , Gordon Kristine A. , Toki Brian E. , Emmerton Kim K. , Zeng Weiping , Stone Ivan J. , Senter Peter D. , Lyon Robert P. , Jeffrey Scott C. 
Published: March 2016

Abstract
A quaternary ammonium-based drug-linker has been developed to expand the scope of antibody–drug conjugate (ADC) payloads to include tertiary amines, a functional group commonly present in biologically active compounds. The linker strategy was exemplified with a β-glucuronidase–cleavable auristatin E construct. The drug-linker was found to efficiently release free auristatin E (AE) in the presence of β-glucuronidase and provide ADCs that were highly stable in plasma. Anti-CD30 conjugates comprised of the glucuronide-AE linker were potent and immunologically specific in vitro and in vivo, displaying pharmacologic properties comparable with a carbamate-linked glucuronide-monomethylauristatin E control. The quaternary ammonium linker was then applied to a tubulysin antimitotic drug that contained an N-terminal tertiary amine that was important for activity. A glucuronide-tubulysin quaternary ammonium linker was synthesized and evaluated as an ADC payload, in which the resulting conjugates were found to be potent and immunologically specific in vitro, and displayed a high level of activity in a Hodgkin lymphoma xenograft. Furthermore, the results were superior to those obtained with a related tubulysin derivative containing a secondary amine N-terminus for conjugation using previously known linker technology. The quaternary ammonium linker represents a significant advance in linker technology, enabling stable conjugation of payloads with tertiary amine residues. Mol Cancer Ther; 15(5); 938–45. ©2016 AACR.
Individualized Statin Benefit for Determining Statin Eligibility in the Primary Prevention of Cardiovascular Disease
Authors: Thanassoulis George , Williams Ken , Altobelli Kathleen Kimler , Pencina Michael J. , Cannon Christopher P. , Sniderman Allan D. 
Published: March 2016

Background—
Current guidelines recommend statins in the primary prevention of cardiovascular disease on the basis of predicted cardiovascular risk without directly considering the expected benefits of statin therapy based on the available randomized, controlled trial evidence.

Methods and Results—

We included 2134 participants representing 71.8 million American residents potentially eligible for statins in primary prevention from the National Health and Nutrition Examination Survey for the years 2005 to 2010. We compared statin eligibilities using 2 separate approaches: a 10-year risk-based approach (≥7.5% 10-year risk) and an individualized benefit approach (ie, based on predicted absolute risk reduction over 10 years [ARR
10
] ≥2.3% from randomized, controlled trial data). A risk-based approach led to the eligibility of 15.0 million (95% confidence interval, 12.7–17.3 million) Americans, whereas a benefit-based approach identified 24.6 million (95% confidence interval, 21.0–28.1 million). The corresponding numbers needed to treat over 10 years were 21 (range, 9–44) and 25 (range, 9–44). The benefit-based approach identified 9.5 million lower-risk (<7.5% 10-year risk) Americans not currently eligible for statin treatment who had the same or greater expected benefit from statins (≥2.3% ARR
10
) compared with higher-risk individuals. This lower-risk/acceptable-benefit group includes younger individuals (mean age, 55.2 versus 62.5 years;
P
<0.001 for benefit based versus risk based) with higher low-density lipoprotein cholesterol (140 versus133 mg/dL;
P
=0.01). Statin treatment in this group would be expected to prevent an additional 266 508 cardiovascular events over 10 years.

Conclusions—
An individualized statin benefit approach can identify lower-risk individuals who have equal or greater expected benefit from statins in primary prevention compared with higher-risk individuals. This approach may help develop guideline recommendations that better identify individuals who meaningfully benefit from statin therapy.
Personnel attitudes toward people with mental illness at a psychiatric hospital in Taiwan
Authors: Chen Ming-De , Chang Yen-Ching 
Published: March 2016

Background: The attitudes of psychiatric hospital personnel are critically related to the quality of mental health care, but few studies have investigated this issue. Aims: This study is aimed at an exploration of the attitudes of psychiatric hospital personnel toward people with mental illness and at an examination of the associated factors. Method: A self-report questionnaire, the Mental Illness Attitude Scale (MIAS), was used to collect data from psychiatric hospital personnel in Taiwan ( n = 290). The MIAS included 46 items and 4 dimensions: acceptance, rehabilitation and prognosis, social distance and recommendations for interventions. Results: Rehabilitation and prognosis had the highest item average scores (4.03) and social distance had the lowest item average scores (3.22). Stigmatization and the number of different types of contacted clients were two significantly associated attitude factors. Conclusion: Psychiatric hospital personnel in Taiwan tend to have positive attitudes toward people with mental illness in general situations but hold less positive attitudes in terms of community integration-related issues and intimate relationships. More evidence-based community services should be conducted to decrease personnel concerns about the successful community integration of those who are mentally ill. Future studies can investigate the concept and impact of stigmatization more deeply.