bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth, developmental and stress responses of larvae of the clouded sulphur butterfly Colias eriphyle to repeated exposure to high, sub‐lethal temperatures
Authors: Higgins Jessica K. , MacLean Heidi J. , Buckley Lauren B. , Kingsolver Joel G. 
Published: May 2015

AbstractThe optimal temperature at which an organism grows and develops is commonly correlated with latitude and elevation; however, the maximum temperature for physiological performance often is not. This makes performance at temperatures between the optimum and the maximum of particular interest. Temperature can influence long‐term performance (growth and development), as well as short‐term performance (heat shock protein) responses differentially. In the present study, two populations of the clouded sulphur butterfly Colias eriphyle Edwards that differ in elevation, thermal regime and optimal and maximum temperatures are studied to quantify their responses to repeated, sub‐lethal heat treatments early in development (second instar). Heat treatments accelerate development during the second to fourth instars in both populations initially, although this effect disappears by pupation. Heat treatment decreases pupal mass in the lower elevation population, suggesting that repeated exposure to high temperatures early in development may reduce final size and fecundity in this population. Heat shock protein gene (hsp70) expression levels in the lower elevation (1633 m a.s.l.) population are highest 24 h after the start of the heat treatment and then the fall to pre‐exposure levels by 36–72 h, suggesting a rapid response to stressful temperatures. By contrast, heat treatment has no significant effect on pupal mass in the higher elevation (2347 m a.s.l.) population. This population has higher levels of hsp70 expression overall but constant expression levels, suggesting that the temperature treatments used are insufficient to elicit a heat stress response. Overall, the effects of repeated exposure to sub‐lethal high temperatures early in development on growth, final size and gene expression differ between populations that differ in thermal sensitivity.
The Effect of Surface Charge Saturation on Heat‐induced Aggregation of Firefly Luciferase
Authors: Gharanlar Jamileh , Hosseinkhani Saman , Sajedi Reza H. , Yaghmaei Parichehr 
Published: May 2015

AbstractWe present here the effect of firefly luciferase surface charge saturation and the presence of some additives on its thermal‐induced aggregation. Three mutants of firefly luciferase prepared by introduction of surface Arg residues named as 2R, 3R and 5R have two, three and five additional arginine residues substituted at their surface compared to native luciferase; respectively. Turbidimetric study of heat‐induced aggregation indicates that all three mutants were reproducibly aggregated at higher rates relative to wild type in spite of their higher thermostability. Among them, 2R had most evaluated propensity to heat‐induced aggregation. Therefore, the hydrophilization followed by appearing of more substituted arginine residues with positive charge on the firefly luciferase surface was not reduced its thermal aggregation. Nevertheless, at the same condition in the presence of charged amino acids, e.g. Arg, Lys and Glu, as well as a hydrophobic amino acid, e.g. Val, the heat‐induced aggregation of wild type and mutants of firefly luciferases was markedly decelerated than those in the absence of additives. On the basis of obtained results it seems, relinquishment of variety in charge of amino acid side chains, they via local interactions with proteins cause to decrease rate and extent of their thermal aggregation.
Modulation of the attentional span by foveal and parafoveal task load: An ERP study using attentional probes
Authors: Kornrumpf Benthe , Sommer Werner 
Published: May 2015

AbstractDue to capacity limitation, visual attention must be focused to a limited region of the visual field. Nevertheless, it is assumed that the size of that region may vary with task demands. We aimed to obtain direct evidence for the modulation of visuospatial attention as a function of foveal and parafoveal task load. Participants were required to fixate the center word of word triplets. In separate task blocks, either just the fixated word or both the fixated and the parafoveal word to the right should be semantically classified. The spatiotemporal distribution of attention was assessed with task‐irrelevant probes flashed briefly at center or parafoveal positions, during or in between word presentation trials. The N1 component of the ERP elicited by intertrial probes at possible target positions increased with task demands within a block. These results suggest the recruitment of additional attentional resources rather than a redistribution of a fixed resource pool, which persists across trials.
A Note on the New Rule for the Current Account
Authors: Erauskin Iñaki 
Published: May 2015

AbstractIn this note, we show that the two main concerns against the new rule for the current account are flawed. The new rule states that the impact of a transitory income shock on the current account is given by the savings generated by the shock multiplied by the ratio of the net foreign asset position to domestic wealth. First, we adapt the new rule to distinguish between gross and net foreign asset positions. Second, we demonstrate that the results for the new rule are driven neither by an accounting‐based “approximate” regression nor a steady state.
Sensitivity of Echinochloa crus‐galli populations to maize herbicides: a comparison between cropping systems
Authors: Claerhout S , Reheul D , De Cauwer B 
Published: May 2015

SummaryEchinochloa crus‐galli is an important maize weed with significant variation in herbicide sensitivity. This differential response may reflect differences in selection pressure caused by years of cropping system‐related herbicide usage. The herbicide sensitivity of E. crus‐galli populations from three divergent cropping systems was evaluated in dose–response pot experiments. Populations were collected from sandy fields with (i) a long‐term organic cropping system, (ii) a conventional cropping system with maize in the crop rotation or (iii) a conventional cropping system with long‐term monocropping of maize. Each cropping system was represented by six E. crus‐galli populations. The effectiveness of three foliar‐applied maize herbicides (nicosulfuron, cycloxydim and topramezone) and two soil‐applied maize herbicides (S‐metolachlor and dimethenamid‐P) was tested at three doses and two runs. Foliar‐applied herbicides were applied at the three true leaves stage. Soil‐applied herbicides were applied immediately after sowing. The foliage dry weight per pot was determined 4 weeks after treatment. Plant responses were expressed as biomass reduction. Herbicide sensitivity was consistently lowest for populations from maize monocropping systems. Compared with populations from organic cropping systems, populations from monocropping systems showed 6.9%, 9.8% and 29.3% lower sensitivity to cycloxydim, topramezone and nicosulfuron respectively. Populations from the conventional crop rotation system showed intermediate sensitivity levels, which did not significantly differ from sensitivity levels of populations from the other cropping systems. Sensitivity to dimethenamid‐P and S‐metolachlor was not affected by cropping system. Environmental conditions influenced herbicidal response. This study indicated that integrated weed management may be necessary to preserve herbicide efficacy over the long term.
Reversed electrogenic sodium bicarbonate cotransporter 1 is the major acid loader during recovery from cytosolic alkalosis in mouse cortical astrocytes
Authors: Theparambil Shefeeq M. , Naoshin Zinnia , Thyssen Anne , Deitmer Joachim W. 
Published: May 2015

Key points
The regulation of H+i from cytosolic alkalosis has generally been attributed to the activity of Cl–‐coupled acid loaders/base extruders in most cell types, including brain cells.
The present study demonstrates that outwardly‐directed sodium bicarbonate cotransport via electrogenic sodium bicarbonate cotransporter 1 (NBCe1) mediates the major fraction of H+i regulation from cytosolic alkalosis in mouse cortical astrocytes.
Cl–‐coupled acid‐loading transporters play only a minor role in the regulation of H+i from alkalosis in mouse cortical astrocytes.
NBCe1‐mediated H+i regulation from alkalosis was dominant, with the support of intracellular carbonic anhydrase II, even when the intra‐ and extracellular [HCO3–] was very low (<1mM), as in nominally CO2/HCO3– free condition.
A reversed NBCe1 in astrocytes may also be significant for stabilizing extracellular pH in brain tissue.
AbstractRecovery of intracellular pH from cytosolic alkalosis has been attributed primarily to Cl– coupled acid loaders/base extruders such as Cl–/HCO3– or Cl–/OH– exchangers. We have studied this process in cortical astrocytes from wild‐type and transgenic mouse models with gene deletion for the electrogenic sodium bicarbonate cotransporter 1 (NBCe1) and for carbonic anhydrase (CA) isoform II. An acute cytosolic alkalosis was induced by the removal of either CO2/HCO3– or butyric acid, and the subsequent acid loading was analysed by monitoring changes in cytosolic H+ or Na+ using ion‐sensitive fluorescent dyes. We have identified that NBCe1 reverses during alkalosis and contributes more than 70% to the rate of recovery from alkalosis by extruding Na+ and HCO3–. After CA inhibition or in CAII‐knockout (KO) cells, the rate of recovery was reduced by 40%, and even by 70% in the nominal absence of CO2/HCO3–. Increasing the extracellular K+ concentration modulated the rate of acid loading in wild‐type cells, but not in NBCe1‐KO cells. Removing chloride had only a minor effect on the recovery from alkalosis. Reversal of NBCe1 by reducing pH/[HCO3–] was demonstrated in astrocytes and in Xenopus oocytes, in which human NBCe1 was heterologously expressed. The results obtained suggest that reversed NBCe1, supported by CAII activity, plays a major role in acid‐loading cortical astrocytes to support recovery from cytosolic alkalosis.
cAMP‐dependent protein kinase inhibits α7 nicotinic receptor activity in layer 1 cortical interneurons through activation of D1/D5 dopamine receptors
Authors: Komal Pragya , Estakhr Jasem , Kamran Melad , Renda Anthony , Nashmi Raad 
Published: May 2015

Key points
Protein kinases can modify the function of many proteins including ion channels.
However, the role of protein kinase A in modifying nicotinic receptors in the CNS has never been investigated.
We showed through whole‐cell recordings of layer 1 prefrontal cortical interneurons that α7 nicotinic responses are negatively modulated by protein kinase A.
Furthermore, we show that stimulation of dopamine receptors can similarly attenuate α7 nicotinic responses through the activation of protein kinase A.
These results suggest how the interaction of the cholinergic and dopaminergic systems may influence neuronal excitability in the brain.
AbstractPhosphorylation of ion channels, including nicotinic acetylcholine receptors (nAChRs), by protein kinases plays a key role in the modification of synaptic transmission and neuronal excitability. α7 nAChRs are the second most prevalent nAChR subtype in the CNS following α4β2. Serine 365 in the M3–M4 cytoplasmic loop of the α7 nAChR is a phosphorylation site for protein kinase A (PKA). D1/D5 dopamine receptors signal through the adenylate cyclase–PKA pathway and play a key role in working memory and attention in the prefrontal cortex. Thus, we examined whether the dopaminergic system, mediated through PKA, functionally interacts with the α7‐dependent cholinergic neurotransmission. In layer 1 interneurons of mouse prefrontal cortex, α7 nicotinic currents were decreased upon stimulation with 8‐Br‐cAMP, a PKA activator. In HEK 293T cells, dominant negative PKA abolished 8‐Br‐cAMP's effect of diminishing α7 nicotinic currents, while a constitutively active PKA catalytic subunit decreased α7 currents. In brain slices, the PKA inhibitor KT‐5720 nullified 8‐Br‐cAMP's effect of attenuating α7 nicotinic responses, while applying a PKA catalytic subunit in the pipette solution decreased α7 currents. 8‐Br‐cAMP stimulation reduced surface expression of α7 nAChRs, but there was no change in single‐channel conductance. The D1/D5 dopamine receptor agonist SKF 83822 similarly attenuated α7 nicotinic currents from layer 1 interneurons and this attenuation of nicotinic current was prevented by KT‐5720. These results demonstrate that dopamine receptor‐mediated activation of PKA negatively modulates nicotinic neurotransmission in prefrontal cortical interneurons, which may be a contributing mechanism of dopamine modulation of cognitive behaviours such as attention or working memory.
Synthetic and Evolutionary Construction of a Chlorate-Reducing Shewanella oneidensis MR-1
Authors: Clark Iain C. , Melnyk Ryan A. , Youngblut Matthew D. , Carlson Hans K. , Iavarone Anthony T. , Coates John D. 
Published: May 2015

ABSTRACT

Despite evidence for the prevalence of horizontal gene transfer of respiratory genes, little is known about how pathways functionally integrate within new hosts. One example of a mobile respiratory metabolism is bacterial chlorate reduction, which is frequently encoded on composite transposons. This implies that the essential components of the metabolism are encoded on these mobile elements. To test this, we heterologously expressed genes for chlorate reduction from

Shewanella alga
e

ACDC in the non-chlorate-reducing
Shewanella oneidensis
MR-1. The construct that ultimately endowed robust growth on chlorate included
cld
, a cytochrome
c
gene,
clrABDC
, and two genes of unknown function. Although strain MR-1 was unable to grow on chlorate after initial insertion of these genes into the chromosome, 11 derived strains capable of chlorate respiration were obtained through adaptive evolution. Genome resequencing indicated that all of the evolved chlorate-reducing strains replicated a large genomic region containing chlorate reduction genes. Contraction in copy number and loss of the ability to reduce chlorate were also observed, indicating that this phenomenon was extremely dynamic. Although most strains contained more than six copies of the replicated region, a single strain with less duplication also grew rapidly. This strain contained three additional mutations that we hypothesized compensated for the low copy number. We remade the mutations combinatorially in the unevolved strain and determined that a single nucleotide polymorphism (SNP) upstream of
cld
enabled growth on chlorate and was epistatic to a second base pair change in the NarP binding sequence between
narQP
and
nrfA
that enhanced growth.

IMPORTANCE
The ability of chlorate reduction composite transposons to form functional metabolisms after transfer to a new host is an important part of their propagation. To study this phenomenon, we engineered
Shewanella oneidensis
MR-1 into a chlorate reducer. We defined a set of genes sufficient to endow growth on chlorate from a plasmid, but found that chromosomal insertion of these genes was nonfunctional. Evolution of this inoperative strain into a chlorate reducer showed that tandem duplication was a dominant mechanism of activation. While copy number changes are a relatively rapid way of increasing gene dosage, replicating almost 1 megabase of extra DNA is costly. Mutations that alleviate the need for high copy number are expected to arise and eventually predominate, and we identified a single nucleotide polymorphism (SNP) that relieved the copy number requirement. This study uses both rational and evolutionary approaches to gain insight into the evolution of a fascinating respiratory metabolism.
Gut Microbial Succession Follows Acute Secretory Diarrhea in Humans
Authors: David Lawrence A. , Weil Ana , Ryan Edward T. , Calderwood Stephen B. , Harris Jason B. , Chowdhury Fahima , Begum Yasmin , Qadri Firdausi , LaRocque Regina C. , Turnbaugh Peter J. 
Published: May 2015

ABSTRACT

Disability after childhood diarrhea is an important burden on global productivity. Recent studies suggest that gut bacterial communities influence how humans recover from infectious diarrhea, but we still lack extensive data and mechanistic hypotheses for how these bacterial communities respond to diarrheal disease and its treatment. Here, we report that after
Vibrio cholerae
infection, the human gut microbiota undergoes an orderly and reproducible succession that features transient reversals in relative levels of enteric
Bacteroides
and
Prevotella
. Elements of this succession may be a common feature in microbiota recovery from acute secretory diarrhea, as we observed similar successional dynamics after enterotoxigenic
Escherichia coli
(ETEC) infection. Our metagenomic analyses suggest that multiple mechanisms drive microbial succession after cholera, including bacterial dispersal properties, changing enteric oxygen and carbohydrate levels, and phage dynamics. Thus, gut microbiota recovery after cholera may be predictable at the level of community structure but is driven by a complex set of temporally varying ecological processes. Our findings suggest opportunities for diagnostics and therapies targeting the gut microbiota in humans recovering from infectious diarrhea.

IMPORTANCE
Disability after diarrhea is a major burden on public health in the developing world. Gut bacteria may affect this recovery, but it remains incompletely understood how resident microbes in the digestive tract respond to diarrheal illness. Here, we observed an orderly and reproducible succession of gut bacterial groups after cholera in humans. Genomic analyses associated the succession with bacterial dispersal in food, an altered microbial environment, and changing phage levels. Our findings suggest that it may one day be feasible to manage resident bacterial populations in the gut after infectious diarrhea.
Genome-Wide siRNA Screen Identifies Complementary Signaling Pathways Involved in
Listeria
Infection and Reveals Different Actin Nucleation Mechanisms during
Listeria
Cell Invasion and Actin Comet Tail Formation
Authors: Kühbacher Andreas , Emmenlauer Mario , Rämo Pauli , Kafai Natasha , Dehio Christoph , Cossart Pascale , Pizarro-Cerdá Javier 
Published: May 2015

ABSTRACT

Listeria monocytogenes
enters nonphagocytic cells by a receptor-mediated mechanism that is dependent on a clathrin-based molecular machinery and actin rearrangements. Bacterial intra- and intercellular movements are also actin dependent and rely on the actin nucleating Arp2/3 complex, which is activated by host-derived nucleation-promoting factors downstream of the cell receptor Met during entry and by the bacterial nucleation-promoting factor ActA during comet tail formation. By genome-wide small interfering RNA (siRNA) screening for host factors involved in bacterial infection, we identified diverse cellular signaling networks and protein complexes that support or limit these processes. In addition, we could precise previously described molecular pathways involved in
Listeria
invasion. In particular our results show that the requirements for actin nucleators during
Listeria
entry and actin comet tail formation are different. Knockdown of several actin nucleators, including SPIRE2, reduced bacterial invasion while not affecting the generation of comet tails. Most interestingly, we observed that in contrast to our expectations, not all of the seven subunits of the Arp2/3 complex are required for
Listeria
entry into cells or actin tail formation and that the subunit requirements for each of these processes differ, highlighting a previously unsuspected versatility in Arp2/3 complex composition and function.

IMPORTANCE
Listeria
is a bacterial pathogen that induces its internalization within the cytoplasm of human cells and has been used for decades as a major molecular tool to manipulate cells in order to explore and discover cellular functions. We have inactivated individually, for the first time in epithelial cells, all the genes of the human genome to investigate whether each gene modifies positively or negatively the
Listeria
infectious process. We identified novel signaling cascades that have never been associated with
Listeria
infection. We have also revisited the role of the molecular complex Arp2/3 involved in the polymerization of the actin cytoskeleton, which was shown previously to be required for
Listeria
entry and movement inside host cells, and we demonstrate that contrary to the general dogma, some subunits of the complex are dispensable for both
Listeria
entry and bacterial movement.
Use of antibiotics in paediatric primary care settings in Serbia
Authors: Bozic Bojana , Bajcetic Milica 
Published: May 2015

ObjectiveThe aim of the study was to compare the quality of antibiotic use among children in primary settings with the internationally developed disease-specific quality indicators and with National Guidelines.DesignPrescriptions of systemic antibiotics to the paediatric population (<18 years) at the primary level of healthcare for the period between 2011 and 2013 were analysed by using the National Health Insurance Fund's outpatient reimbursement database.ResultsThe mean annual number of antibiotic prescriptions was 1.887.615, while the mean annual number of children receiving antibiotics was 728.285. The prescription rate slightly decreased by 10% from 1.516 antibiotic prescriptions per 1000 persons per year in 2011 to 1.365 in 2013. The highest percentage of prescribed antibiotics was observed in the group of children aged 2–23 months. The mean annual prevalence of antibiotic prescriptions was 54%. The percentage of patients prescribed an antibiotic for acute upper respiratory tract infections, acute tonsillitis and acute otitis media (AOM) was above the proposed range (≤20), 87% –96%. These three diagnoses represent more than 69% of all indications for prescribing antibiotics. The percentage of patients prescribed a recommended antibiotic was below the proposed range (≥80%), 1% –17%, while the adherence rate to National Guidelines was low, 19%–28%. The percentage of patients prescribed quinolones was above the proposed range for AOM (≤5%), 7%. There were no significant differences in indicators value at the regional level in Serbia.ConclusionsAntibiotic use among children in Serbia is extremely high compared with that in most other European countries. Major problems are frequent use of antibiotics for indications that usually receive no benefit from this treatment and the use of broad-spectrum antibiotics.