bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human muscle fibre type‐specific regulation of AMPK and downstream targets by exercise
Authors: Kristensen Dorte E. , Albers Peter H. , Prats Clara , Baba Otto , Birk Jesper B. , Wojtaszewski Jørgen F. P. 
Published: January 2015

Keypoints
AMP‐activated protein kinase (AMPK) is an important regulator of cellular energy status during exercise.
Most human studies investigating skeletal muscle protein signalling have been performed in whole muscle biopsy samples, yet recent studies suggest muscle fibre type‐specific AMPK expression with potential fibre type‐specific regulation of AMPK during exercise.
This study provides novel and comprehensive data on human muscle fibre type‐specific expression levels of AMPK subunits and downstream targets of AMPK.
We show a differentiated response to exercise of key metabolic signalling proteins in human type I and type II muscle fibres during interval exercise, not evident during continuous exercise. These differences between exercise types were not present in whole muscle biopsy samples.
Our findings highlight the importance of performing fibre type‐specific measurements and the increased activation of AMPK in interval vs. continuous exercise could be important for exercise type‐specific adaptations, i.e. metabolism, insulin sensitivity and mitochondrial density in human skeletal muscle.
AbstractAMP‐activated protein kinase (AMPK) is a regulator of energy homeostasis during exercise. Studies suggest muscle fibre type‐specific AMPK expression. However, fibre type‐specific regulation of AMPK and downstream targets during exercise has not been demonstrated. We hypothesized that AMPK subunits are expressed in a fibre type‐dependent manner and that fibre type‐specific activation of AMPK and downstream targets is dependent on exercise intensity. Pools of type I and II fibres were prepared from biopsies of vastus lateralis muscle from healthy men before and after two exercise trials: (1) continuous cycling (CON) for 30 min at 69 ± 1% peak rate of O2 consumption () or (2) interval cycling (INT) for 30 min with 6 × 1.5 min high‐intensity bouts peaking at 95 ± 2% . In type I vs. II fibres a higher β1 AMPK (+215%) and lower γ3 AMPK expression (−71%) was found. α1, α2, β2 and γ1 AMPK expression was similar between fibre types. In type I vs. II fibres phosphoregulation after CON was similar (AMPKThr172, ACCSer221, TBC1D1Ser231 and GS2+2a) or lower (TBC1D4Ser704). Following INT, phosphoregulation in type I vs. II fibres was lower (AMPKThr172, TBC1D1Ser231, TBC1D4Ser704 and ACCSer221) or higher (GS2+2a). Exercise‐induced glycogen degradation in type I vs. II fibres was similar (CON) or lower (INT). In conclusion, a differentiated response to exercise of metabolic signalling/effector proteins in human type I and II fibres was evident during interval exercise. This could be important for exercise type‐specific adaptations, i.e. insulin sensitivity and mitochondrial density, and highlights the potential for new discoveries when investigating fibre type‐specific signalling.
Rapid changes in NADH and flavin autofluorescence in rat cardiac trabeculae reveal large mitochondrial complex II reserve capacity
Authors: Wüst Rob C. I. , Helmes Michiel , Stienen Ger J. M. 
Published: January 2015

Key points
A photometry‐based technique was developed to measure nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) autofluorescence and contractile properties simultaneously in intact rat trabeculae at a high time resolution. This provides insight into the function of mitochondrial complex I and II.
Maximal complex I and complex II activities were determined in saponin‐permeabilized right ventricular tissue by respirometry.
In trabeculae, complex II function was considerably smaller than the maximal complex II activity, suggesting large complex II reserve capacity.
Up–down asymmetry in NADH and FAD kinetics suggests a complex interaction between mitochondrial and contractile function.
These data show that simultaneous measurement of contractile properties and NADH and FAD kinetics in cardiac trabeculae provides a mean to study the differences in complex I and II function in intact preparations in health and disease.
AbstractThe functional properties of cardiac mitochondria in intact preparations have been mainly studied by measurements of nicotinamide adenine dinucleotide (NADH) autofluorescence, which reflects mitochondrial complex I function. To assess complex II function, we extended this method by measuring flavin adenine dinucleotide (FAD)‐related autofluorescence in electrically stimulated cardiac trabeculae isolated from the right ventricle from the rat at 27°C. NADH and FAD autofluorescence and tension responses were measured when stimulation frequency was increased from 0.5 Hz to 1, 2 or 3 Hz for 3 min, and thereafter decreased to 0.5 Hz. Maximal complex I and complex II activity in vitro were determined in saponin‐permeabilized right ventricular tissue by respirometry. NADH responses upon an increase in stimulation frequency showed a rapid decline, followed by a slow recovery towards the initial level. FAD responses followed a similar time course, but in the opposite direction. The amplitudes of early rapid changes in the NADH and FAD concentration correlated well with the change in tension time integral per second (R2 = 0.833 and 0.660 for NADH and FAD, respectively), but with different slopes for the up and down transient. Maximal velocity of the increase in FAD concentration (16 ± 4 μm s−1), measured upon an increase in stimulation frequency from 0.5 to 3 Hz was considerably smaller than that of the decrease in NADH (78 ± 13 μm s−1). The respiration measurements indicated that the maximal velocity of NADH utilization (143 ± 14 μm s−1) was 2 times smaller than that of FADH2 (291 ± 19 μm s−1). This indicates that in cardiac mitochondria considerable complex II activity reserve is present.
Actin cytoskeletal rearrangement and dysfunction due to activation of the receptor for advanced glycation end products is inhibited by thymosin beta 4
Authors: Kim Sokho , Kwon Jungkee 
Published: January 2015

Key points
Thymosin beta 4 (Tβ4) attenuates the vascular cellular toxicity induced by advanced glycation end products (AGEs) in human umbilical vein endothelial cells (HUVECs).
Tβ4 reduces expression of both the receptor of AGEs (RAGE) and the filamentous actin (F‐actin) to globular actin (G‐actin) ratio.
RAGE expression was regulated by actin cytoskeleton involved in Tβ4.
Tβ4 attenuates the vascular cellular toxicity induced by AGEs via remodelling of the actin cytoskeleton.
AGEs attenuate vascular‐like tube formation of HUVECs, which is reversed by Tβ4 via remodelling of the actin cytoskeleton.
AbstractThe receptor of advanced glycation end products (RAGE) is a cell‐surface receptor that is a key factor in the pathogenesis of diabetic complications, including vascular disorders. Dysfunction of the actin cytoskeleton contributes to disruption of cell membrane repair in response to various type of endothelial cell damage. However, mechanism underlying RAGE remodelling of the actin cytoskeleton, by which globular actin (G‐actin) forms to filamentous actin (F‐actin), remains unclear. In this study we examined the role of thymosin beta 4 (Tβ4) – which binds to actin, blocks actin polymerization, and maintains the dynamic equilibrium between G‐actin and F‐actin in human umbilical vein endothelial cells (HUVECs) – in the response to RAGE. Tβ4 increased cell viability and decreased levels of reactive oxygen species in HUVECs incubated with AGEs. Tβ4 reduced the expression of RAGE, consistent with a down‐regulation of the F‐actin to G‐actin ratio. The effect of remodelling of the actin cytoskeleton on RAGE expression was clarified by adding Phalloidin, which stabilizes F‐actin. Moreover, small interfering RNA was used to determine whether intrinsic Tβ4 regulates RAGE expression in the actin cytoskeleton. The absence of intrinsic Tβ4 in HUVECs evoked actin cytoskeleton disorder and increased RAGE expression. These findings suggest that regulation of the actin cytoskeleton by Tβ4 plays a pivotal role in the RAGE response to AGEs.
On effective dose for radiotherapy based on doses to nontarget organs and tissues
Authors: Uselmann Adam J. , Thomadsen Bruce R. 
Published: January 2015

Purpose:The National Council for Radiation Protection and Measurement (NCRP) published estimates for the collective population dose and the mean effective dose to the population of the United States from medical imaging procedures for 1980/1982 and for 2006. The earlier report ignored the effective dose from radiotherapy and the latter gave a cursory discussion of the topic but again did not include it in the population exposure for various reasons. This paper explains the methodology used to calculate the effective dose in due to radiotherapy procedures in the latter NCRP report and revises the values based on more detailed modeling.Methods:This study calculated the dose to nontarget organs from radiotherapy for reference populations using CT images and published peripheral dose data.Results:Using International Commission on Radiological Protection (ICRP) 60 weighting factors, the total effective dose to nontarget organs in radiotherapy patients is estimated as 298 ± 194 mSv per patient, while the U.S. population effective dose is 0.939 ± 0.610 mSv per person, with a collective dose of 283 000 ± 184 000 person Sv per year. Using ICRP 103 weighting factors, the effective dose is 281 ± 183 mSv per patient, 0.887 ± 0.577 mSv per person in the U.S., and 268 000 ± 174 000 person Sv per year. The uncertainty in the calculations is largely governed by variations in patient size, which was accounted for by considering a range of patient sizes and taking the average treatment site to nontarget organ distance.Conclusions:The methods used to estimate the effective doses from radiotherapy used in NCRP Report No. 160 have been explained and the values updated.
Natural Hot Spots for Gain of Multiple Resistances: Arsenic and Antibiotic Resistances in Heterotrophic, Aerobic Bacteria from Marine Hydrothermal Vent Fields
Authors: Farias Pedro , Espírito Santo Christophe , Branco Rita , Francisco Romeu , Santos Susana , Hansen Lars , Sorensen Soren , Morais Paula V. 
Published: January 2015

ABSTRACT

Microorganisms are responsible for multiple antibiotic resistances that have been associated with resistance/tolerance to heavy metals, with consequences to public health. Many genes conferring these resistances are located on mobile genetic elements, easily exchanged among phylogenetically distant bacteria. The objective of the present work was to isolate arsenic-, antimonite-, and antibiotic-resistant strains and to determine the existence of plasmids harboring antibiotic/arsenic/antimonite resistance traits in phenotypically resistant strains, in a nonanthropogenically impacted environment. The hydrothermal Lucky Strike field in the Azores archipelago (North Atlantic, between 11°N and 38°N), at the Mid-Atlantic Ridge, protected under the OSPAR Convention, was sampled as a metal-rich pristine environment. A total of 35 strains from 8 different species were isolated in the presence of arsenate, arsenite, and antimonite. ACR3 and
arsB
genes were amplified from the sediment's total DNA, and 4 isolates also carried ACR3 genes. Phenotypic multiple resistances were found in all strains, and 7 strains had recoverable plasmids. Purified plasmids were sequenced by Illumina and assembled by EDENA V3, and contig annotation was performed using the “Rapid Annotation using the Subsystems Technology” server. Determinants of resistance to copper, zinc, cadmium, cobalt, and chromium as well as to the antibiotics β-lactams and fluoroquinolones were found in the 3 sequenced plasmids. Genes coding for heavy metal resistance and antibiotic resistance in the same mobile element were found, suggesting the possibility of horizontal gene transfer and distribution of theses resistances in the bacterial population.
Sediment and Vegetation as Reservoirs of Vibrio vulnificus in the Tampa Bay Estuary and Gulf of Mexico
Authors: Chase Eva , Young Suzanne , Harwood Valerie J. 
Published: January 2015

ABSTRACT

The opportunistic pathogen
Vibrio vulnificus
occurs naturally in estuarine habitats and is readily cultured from water and oysters under warm conditions but infrequently at ambient conditions of <15°C. The presence of
V. vulnificus
in other habitats, such as sediments and aquatic vegetation, has been explored much less frequently. This study investigated the ecology of
V. vulnificus
in water by culture and quantitative PCR (qPCR) and in sediment, oysters, and aquatic vegetation by culture.
V. vulnificus
samples were taken from five sites around Tampa Bay, FL. Levels determined by qPCR and culture were significantly correlated (
P
= 0.0006;
r
= 0.352); however,
V. vulnificus
was detected significantly more frequently by qPCR (85% of all samples) compared to culture (43%). Culturable
V. vulnificus
bacteria were recovered most frequently from oyster samples (70%), followed by vegetation and sediment (∼50%) and water (43%). Water temperature, which ranged from 18.5 to 33.4°C, was positively correlated with
V. vulnificus
concentrations in all matrices but sediments. Salinity, which ranged from 1 to 35 ppt, was negatively correlated with
V. vulnificus
levels in water and sediments but not in other matrices. Significant interaction effects between matrix and temperature support the hypothesis that temperature affects
V. vulnificus
concentrations differently in different matrices and that sediment habitats may serve as seasonal reservoirs for
V. vulnificus
.
V. vulnificus
levels in vegetation have not been previously measured and reveal an additional habitat for this autochthonous estuarine bacterium.
Gas Chromatography-Mass Spectrometry-Based Metabolite Profiling of Salmonella enterica Serovar Typhimurium Differentiates between Biofilm and Planktonic Phenotypes
Authors: Wong Hui San , Maker Garth L. , Trengove Robert D. , O'Handley Ryan M. 
Published: January 2015

ABSTRACT

The aim of this study was to utilize gas chromatography coupled with mass spectrometry (GC-MS) to compare and identify patterns of biochemical change between
Salmonella
cells grown in planktonic and biofilm phases and
Salmonella
biofilms of different ages. Our results showed a clear separation between planktonic and biofilm modes of growth. The majority of metabolites contributing to variance between planktonic and biofilm supernatants were identified as amino acids, including alanine, glutamic acid, glycine, and ornithine. Metabolites contributing to variance in intracellular profiles were identified as succinic acid, putrescine, pyroglutamic acid, and
N
-acetylglutamic acid. Principal-component analysis revealed no significant differences between the various ages of intracellular profiles, which would otherwise allow differentiation of biofilm cells on the basis of age. A shifting pattern across the score plot was illustrated when analyzing extracellular metabolites sampled from different days of biofilm growth, and amino acids were again identified as the metabolites contributing most to variance. An understanding of biofilm-specific metabolic responses to perturbations, especially antibiotics, can lead to the identification of novel drug targets and potential therapies for combating biofilm-associated diseases. We concluded that under the conditions of this study, GC-MS can be successfully applied as a high-throughput technique for “bottom-up” metabolomic biofilm research.
Inducible Suppression of Global Translation by Overuse of Rare Codons
Authors: Kobayashi Hideki 
Published: January 2015

ABSTRACT

Recently, artificial gene networks have been developed in synthetic biology to control gene expression and make organisms as controllable as robots. Here, I present an artificial posttranslational gene-silencing system based on the codon usage bias and low tRNA content corresponding to minor codons. I engineered the green fluorescent protein (GFP) gene to inhibit translation indirectly with the lowest-usage codons to monopolize various minor tRNAs (
lgfp
). The expression of
lgfp
interfered nonspecifically with the growth of
Escherichia coli
,
Saccharomyces cerevisiae
, human HeLa cervical cancer cells, MCF7 breast cancer cells, and HEK293 kidney cells, as well as phage and adenovirus expansion. Furthermore, insertion of
lgfp
downstream of a phage response promoter conferred phage resistance on
E. coli
. Such engineered gene silencers could act as components of biological networks capable of functioning with suitable promoters in
E. coli
,
S. cerevisiae
, and human cells to control gene expression. The results presented here show general suppressor artificial genes for live cells and viruses. This robust system provides a gene expression or cell growth control device for artificially synthesized gene networks.
Genome-Wide Transcriptional Responses to Carbon Starvation in Nongrowing Lactococcus lactis
Authors: Ercan Onur , Wels Michiel , Smid Eddy J. , Kleerebezem Michiel 
Published: January 2015

ABSTRACT

This paper describes the transcriptional adaptations of nongrowing, retentostat cultures of
Lactococcus lactis
to starvation. Near-zero-growth cultures (μ = 0.0001 h
−1
) obtained by extended retentostat cultivation were exposed to starvation by termination of the medium supply for 24 h, followed by a recovery period of another 24 h by reinitiating the medium supply to the retentostat culture. During starvation, the viability of the culture was largely retained, and the expression of genes involved in transcription and translational machineries, cell division, and cell membrane energy metabolism was strongly repressed. Expression of these genes was largely recovered following the reinitiation of the medium supply. Starvation triggered the elevated expression of genes associated with synthesis of branched-chain amino acids, histidine, purine, and riboflavin. The expression of these biosynthesis genes was found to remain at an elevated level after reinitiation of the medium supply. In addition, starvation induced the complete gene set predicted to be involved in natural competence in
L. lactis
KF147, and the elevated expression of these genes was sustained during the subsequent recovery period, but our attempts to experimentally demonstrate natural transformation in these cells failed. Mining the starvation response gene set identified a conserved
cis
-acting element that resembles the lactococcal CodY motif in the upstream regions of genes associated with transcription and translational machineries, purine biosynthesis, and natural transformation in
L. lactis
, suggesting a role for CodY in the observed transcriptome adaptations to starvation in nongrowing cells.
Development of a Protocol for Predicting Bacterial Resistance to Microbicides
Authors: Knapp Laura , Amézquita Alejandro , McClure Peter , Stewart Sara , Maillard Jean-Yves 
Published: January 2015

ABSTRACT

Regulations dealing with microbicides in Europe and the United States are evolving and now require data on the risk of the development of resistance in organisms targeted by microbicidal products. There is no standard protocol to assess the risk of the development of resistance to microbicidal formulations. This study aimed to validate the use of changes in microbicide and antibiotic susceptibility as initial markers for predicting microbicide resistance and cross-resistance to antibiotics. Three industrial isolates (
Pseudomonas aeruginosa
,
Burkholderia cepacia
, and
Klebsiella pneumoniae
) and two
Salmonella enterica
serovar Typhimurium strains (SL1344 and 14028S) were exposed to a shampoo, a mouthwash, eye makeup remover, and the microbicides contained within these formulations (chlorhexidine digluconate [CHG] and benzalkonium chloride [BZC]) under realistic, in-use conditions. Baseline and postexposure data were compared. No significant increases in the MIC or the minimum bactericidal concentration (MBC) were observed for any strain after exposure to the three formulations. Increases as high as 100-fold in the MICs and MBCs of CHG and BZC for SL1344 and 14028S were observed but were unstable. Changes in antibiotic susceptibility were not clinically significant. The use of MICs and MBCs combined with antibiotic susceptibility profiling and stability testing generated reproducible data that allowed for an initial prediction of the development of resistance to microbicides. These approaches measure characteristics that are directly relevant to the concern over resistance and cross-resistance development following the use of microbicides. These are low-cost, high-throughput techniques, allowing manufacturers to provide to regulatory bodies, promptly and efficiently, data supporting an early assessment of the risk of resistance development.
Molecular Gene Profiling of Clostridium botulinum Group III and Its Detection in Naturally Contaminated Samples Originating from Various European Countries
Authors: Woudstra Cedric , Le Maréchal Caroline , Souillard Rozenn , Bayon-Auboyer Marie-Hélène , Anniballi Fabrizio , Auricchio Bruna , De Medici Dario , Bano Luca , Koene Miriam , Sansonetti Marie-Hélène , Desoutter Denise , Hansbauer Eva-Maria , Dorner Martin B. , Dorner Brigitte G. , Fach Patrick 
Published: January 2015

ABSTRACT

We report the development of real-time PCR assays for genotyping
Clostridium botulinum
group III targeting the newly defined
C. novyi sensu lato
group; the nontoxic nonhemagglutinin (NTNH)-encoding gene
ntnh
; the botulinum neurotoxin (BoNT)-encoding genes
bont/C
,
bont/C/D
,
bont/D
, and
bont/D/C
; and the flagellin (
fliC
) gene. The genetic diversity of
fliC
among
C. botulinum
group III strains resulted in the definition of five major subgroups named
fliC
-I to
fliC
-V. Investigation of
fliC
subtypes in 560 samples, with various European origins, showed that
fliC
-I was predominant and found exclusively in samples contaminated by
C. botulinum
type C/D,
fliC
-II was rarely detected, no sample was recorded as
fliC
-III or
fliC
-V, and only
C. botulinum
type D/C samples tested positive for
fliC
-IV. The lack of genetic diversity of the flagellin gene of
C. botulinum
type C/D would support a clonal spread of type C/D strains in different geographical areas.
fliC
-I to
fliC
-III are genetically related (87% to 92% sequence identity), whereas
fliC
-IV from
C. botulinum
type D/C is more genetically distant from the other
fliC
types (with only 50% sequence identity). These findings suggest
fliC
-I to
fliC
-III have evolved in a common environment and support a different genetic evolution for
fliC
-IV. A combination of the
C. novyi sensu lato
,
ntnh
,
bont
, and
fliC
PCR assays developed in this study allowed better characterization of
C. botulinum
group III and showed the group to be less genetically diverse than
C. botulinum
groups I and II, supporting a slow genetic evolution of the strains belonging to
C. botulinum
group III.