bluuebunny/crossref_metadata_2025_split huggingface dataset:
The monolignol pathway contributes to the biosynthesis of volatile phenylpropenes in flowers
Authors: Muhlemann Joëlle K. , Woodworth Benjamin D. , Morgan John A. , Dudareva Natalia 
Published: July 2014

Summary

Volatile phenylpropenes play important roles in the mediation of interactions between plants and their biotic environments. Their biosynthesis involves the elimination of the oxygen functionality at the side‐chain of monolignols and competes with lignin formation for monolignol utilization. We hypothesized that biochemical steps before the monolignol branch point are shared between phenylpropene and lignin biosynthesis; however, genetic evidence for this shared pathway has been missing until now.

Our hypothesis was tested by RNAi suppression of the petunia (Petunia hybrida) cinnamoyl‐CoA reductase 1 (PhCCR1), which catalyzes the first committed step in monolignol biosynthesis. Detailed metabolic profiling and isotopic labeling experiments were performed in petunia transgenic lines.

Downregulation of PhCCR1 resulted in reduced amounts of total lignin and decreased flux towards phenylpropenes, whereas internal and emitted pools of phenylpropenes remained unaffected. Surprisingly, PhCCR1 silencing increased fluxes through the general phenylpropanoid pathway by upregulating the expression of cinnamate‐4‐hydroxylase (C4H), which catalyzes the second reaction in the phenylpropanoid pathway.

In conclusion, our results show that PhCCR1 is involved in both the biosynthesis of phenylpropenes and lignin production. However, PhCCR1 does not perform a rate‐limiting step in the biosynthesis of phenylpropenes, suggesting that scent biosynthesis is prioritized over lignin formation in petals.
Forecasting GDP over the Business Cycle in a Multi‐Frequency and Data‐Rich Environment
Authors: Bessec Marie , Bouabdallah Othman 
Published: July 2014

AbstractThis paper merges two specifications recently developed in the forecasting literature: the MS‐MIDAS model (Guérin and Marcellino, 2013) and the factor‐MIDAS model (Marcellino and Schumacher, 2010). The MS‐factor MIDAS model that we introduce incorporates the information provided by a large data set consisting of mixed frequency variables and captures regime‐switching behaviours. Monte Carlo simulations show that this specification tracks the dynamics of the process and predicts the regime switches successfully, both in‐sample and out‐of‐sample. We apply this model to US data from 1959 to 2010 and properly detect recessions by exploiting the link between GDP growth and higher frequency financial variables.
Does Co‐authorship Lead to Higher Academic Productivity?
Authors: Ductor Lorenzo 
Published: July 2014

AbstractIn recent decades, co‐authorship and policies aimed at inducing academic collaboration have increased simultaneously. Assuming that intellectual collaboration is exogenously determined, prior studies found a negative relationship between co‐authorship and productivity. I examine a panel data on economists publishing from 1970 to 2011 to test the causal effect of intellectual collaboration on intellectual output. As characteristics of the individual and her opportunity set are endogenously related to both collaboration and productivity, I instrument the amount of co‐authorship by the common research interest between an author and her potential co‐authors. After controlling for endogenous co‐authorship formation, unobservable heterogeneity and time varying factors, the effect of intellectual collaboration on individual performance becomes positive.
Increase of fast nutrient cycling in grassland microcosms through insect herbivory depends on plant functional composition and species diversity
Authors: Nitschke Norma , Wiesner Kerstin , Hilke Ines , Eisenhauer Nico , Oelmann Yvonne , Weisser Wolfgang W. 
Published: July 2014

Nutrient cycling in terrestrial ecosystems is affected by various factors such as plant diversity and insect herbivory. While several studies suggest insect herbivory to depend on plant diversity, their interacting effect on nutrient cycling is unclear.In a greenhouse experiment with grassland microcosms of one to six plant species of two functional groups (grasses and legumes), we tested the influence of plant species richness (diversity) and functional composition on plant community biomass production, insect foliar herbivory, soil microbial biomass, and nutrient concentrations in throughfall. To manipulate herbivory, zero, three or six generalist grasshoppers (Chorthippus parallelus) were added to the plant communities.Increasing plant species richness increased shoot biomass and grasshopper performance, without significantly affecting root biomass or insect herbivory. Plant functional composition affected all of these parameters, e.g. legume communities showed the highest shoot biomass, the lowest grasshopper performance and suffered the least herbivory. Nutrient concentrations (dissolved mineral N, PO4‐P, SO4‐S) and pH in throughfall increased with herbivory. PO4‐P and pH increases were positively affected by plant diversity, especially under high herbivore pressure. Plant functional composition affected several throughfall variables, sometimes fully explaining diversity effects. Increasing plant diversity tended to increase soil microbial biomass, but only under high herbivore pressure. Faeces quantities strongly correlated with changes in pH and PO4‐P; frass may therefore be an important driver of throughfall pH and a main source of PO4‐P released from living plants. Our results indicate that insect herbivory may significantly influence fast nutrient cycling processes in natural communities, particularly so in managed grasslands.
Efficient transformation and artificial miRNA gene silencing in Lemna minor
Authors: Cantó‐Pastor A. , Mollá‐Morales A. , Ernst E. , Dahl W. , Zhai J. , Yan Y. , Meyers B. C. , Shanklin J. , Martienssen R. 
Published: July 2014

AbstractDespite rapid doubling time, simple architecture and ease of metabolic labelling, a lack of genetic tools in the Lemnaceae (duckweed) has impeded the full implementation of this organism as a model for biological research. Here, we present technologies to facilitate high‐throughput genetic studies in duckweed. We developed a fast and efficient method for producing Lemna minor stable transgenic fronds via Agrobacterium‐mediated transformation and regeneration from tissue culture. Additionally, we engineered an artificial microRNA (amiRNA) gene silencing system. We identified a Lemna gibba endogenous miR166 precursor and used it as a backbone to produce amiRNAs. As a proof of concept we induced the silencing of CH42, a magnesium chelatase subunit, using our amiRNA platform. Expression of CH42 in transgenic L. minor fronds was significantly reduced, which resulted in reduction of chlorophyll pigmentation. The techniques presented here will enable tackling future challenges in the biology and biotechnology of Lemnaceae.
A novel Dual Probe Complex Trial Protocol for detection of concealed information
Authors: Labkovsky Elena , Rosenfeld J. Peter 
Published: July 2014

AbstractIn simply guilty (SG), countermeasure‐using guilty (CM), and innocent (IN) subjects, a new concealed information test, the P300‐based Dual Probe Complex Trial Protocol was tested in a mock crime scenario. It combines an oddball protocol with two stimuli (probe, irrelevant) and another with three stimuli (probe, irrelevant, target) into one trial, doubling detected mock crime information per unit time, compared to previous protocols. Probe‐irrelevant amplitude differences were significant in SG and CM, but not IN subjects. On a measure from both two and three stimulus protocol parts of the Dual Probe Complex Trial Protocol trial, accuracy was 94.7% (based on a .9 bootstrap criterion). The criterion‐independent area (AUC) under the receiver operating characteristic (from signal detection theory) measuring SG and CM versus IN discriminability averaged .92 (in a range of 0.5–1.0). Countermeasures enhanced irrelevant (not probe) P300s in CM groups.
Hysteresis in Potential Output and Monetary Policy
Authors: Kienzler Daniel , Schmid Kai D. 
Published: July 2014

AbstractWe show that actively stabilizing economic activity plays a more prominent role in the conduct of monetary policy when potential output is subject to hysteresis. We augment a basic New Keynesian model by hysteresis in potential output and contrast simulation outcomes of this extended model to the standard model. We find that considering hysteresis allows for a more realistic amplification of macroeconomic shocks and persistent movements in output after monetary shocks. Our central policy implication of active output gap stabilization arises from stability analyses and welfare considerations.
Should They Stay or Should They Go? Attitudes Towards Immigration in Europe
Authors: Bridges Sarah , Mateut Simona 
Published: July 2014

AbstractThis paper examines the main determinants of individual attitudes towards immigration inEurope. Our results suggest that both economic and non‐economic variables shape attitudes towards immigration, but the relative importance of these factors depends crucially on the race/ethnicity of the arriving immigrants. While fears over labour market competition are more likely to shape attitudes towards the arrival of same race immigrants, more exposure to immigrants reduces opposition towards the arrival of different race immigrants. These findings persist after controlling for socioeconomic characteristics, and after exploiting the data to allow for cohort‐specific effects.
The Dynamics of Aid and Political Rights
Authors: Fielding David 
Published: July 2014

AbstractUsing cross‐country panel data, we explore the extent to which the variation over time in measures of democracy and political rights can be explained by changes in aid inflows, thus providing direct evidence on the impact of innovations in donor policy on the quality of recipient governance. We distinguish between the short‐run and long‐run effects of changes in aid. Our results are very different from those based on cross‐country variation in aid inflows. We find evidence of large differences between the effect of aid for political reform and the effect of other types of aid in aggregate. These effects also depend on the recipient country's initial level of political development. There is no evidence that aid intended for political reform has achieved its objective, and in some countries, it may be counterproductive. However, aggregate aid can have a beneficial effect on political rights.
Erythrocytes from GGTA1/CMAH knockout pigs: implications for xenotransfusion and testing in non‐human primates
Authors: Wang Zheng‐Yu , Burlak Christopher , Estrada Jose L. , Li Ping , Tector Matthew F. , Tector A. Joseph 
Published: July 2014

AbstractBackgroundPig erythrocytes are potentially useful to solve the worldwide shortage of human blood for transfusion. Domestic pig erythrocytes, however, express antigens that are bound by human preformed antibodies. Advances in genetic engineering have made it possible to rapidly knock out the genes of multiple xenoantigens, namely galactose α1,3 galactose (aGal) and N‐glycolylneuraminic acid (Neu5Gc). We have recently targeted the GGTA1 and CMAH genes with zinc finger endonucleases resulting in double knockout pigs that no longer express aGal or Neu5Gc and attract significantly fewer human antibodies. In this study, we characterized erythrocytes from domestic and genetically modified pigs, baboons, chimpanzees, and humans for binding of human and baboon natural antibody, and complement‐mediated lysis.MethodsDistribution of anti‐Neu5Gc IgG and IgM in pooled human AB serum was analyzed by ELISA. Erythrocytes from domestic pigs (Dom), aGal knockout pigs (GGTA1 KO), aGal and Neu5Gc double knockout pigs (GGTA1/CMAH KO), baboons, chimpanzees, and humans were analyzed by flow cytometry for aGal and Neu5Gc expression. In vitro comparative analysis of erythrocytes was conducted with pooled human AB serum and baboon serum. Total antibody binding was accessed by hemagglutination; complement‐dependent lysis was measured by hemolytic assay; IgG or IgM binding to erythrocytes was characterized by flow cytometry.ResultsThe pooled human AB serum contained 0.38 μg/ml anti‐Neu5Gc IgG and 0.085 μg/ml anti‐Neu5Gc IgM. Both Gal and Neu5Gc were not detectable on GGTA1/CMAH KO erythrocytes. Hemagglutination of GGTA1/CMAH KO erythrocytes with human serum was 3.5‐fold lower compared with GGTA1 KO erythrocytes, but 1.6‐fold greater when agglutinated with baboon serum. Hemolysis of GGTA1/CMAH KO erythrocytes by human serum (25%) was reduced 9‐fold compared with GGTA1 KO erythrocytes, but increased 1.64‐fold by baboon serum. Human IgG binding was reduced 27‐fold on GGTA1/CMAH KO erythrocytes compared with GGTA1 KO erythrocytes, but markedly increased 3‐fold by baboon serum IgG. Human IgM binding was decreased 227‐fold on GGTA1/CMAH KO erythrocytes compared with GGTA1 KO erythrocytes, but enhanced 5‐fold by baboon serum IgM.ConclusionsRemoval of aGal and Neu5Gc antigens from pig erythrocytes significantly reduced human preformed antibody‐mediated cytotoxicity but may have complicated future in vivo analysis by enhancing reactivity from baboons. The creation of the GGTA1/CMAH KO pig has provided the xenotransplantation researcher with organs and cells that attract fewer human antibodies than baboon and our closest primate relative, chimpanzee. These finding suggest that while GGTA1/CMAH KO erythrocytes may be useful for human transfusions, in vivo testing in the baboon may not provide a direct transplantation to the clinic.
Campylobacter jejuni Is Not Merely a Commensal in Commercial Broiler Chickens and Affects Bird Welfare
Authors: Humphrey Suzanne , Chaloner Gemma , Kemmett Kirsty , Davidson Nicola , Williams Nicola , Kipar Anja , Humphrey Tom , Wigley Paul 
Published: July 2014

ABSTRACT

Campylobacter jejuni
is the leading cause of bacterial food-borne infection; chicken meat is its main source.
C. jejuni
is considered commensal in chickens based on experimental models unrepresentative of commercial production. Here we show that the paradigm of
Campylobacter
commensalism in the chicken is flawed. Through experimental infection of four commercial breeds of broiler chickens, we show that breed has a significant effect on
C. jejuni
infection and the immune response of the animals, although these factors have limited impact on the number of bacteria in chicken ceca. All breeds mounted an innate immune response. In some breeds, this response declined when interleukin-10 was expressed, consistent with regulation of the intestinal inflammatory response, and these birds remained healthy. In another breed, there was a prolonged inflammatory response, evidence of damage to gut mucosa, and diarrhea. We show that bird type has a major impact on infection biology of
C. jejuni
. In some breeds, infection leads to disease, and the bacterium cannot be considered a harmless commensal. These findings have implications for the welfare of chickens in commercial production where
C. jejuni
infection is a persistent problem.

IMPORTANCE
Campylobacter jejuni
is the most common cause of food-borne bacterial diarrheal disease in the developed world. Chicken is the most common source of infection.
C. jejuni
infection of chickens had previously not been considered to cause disease, and it was thought that
C. jejuni
was part of the normal microbiota of birds. In this work, we show that modern rapidly growing chicken breeds used in intensive production systems have a strong inflammatory response to
C. jejuni
infection that can lead to diarrhea, which, in turn, leads to damage to the feet and legs on the birds due to standing on wet litter. The response and level of disease varied between breeds and is related to regulation of the inflammatory immune response. These findings challenge the paradigm that
C. jejuni
is a harmless commensal of chickens and that
C. jejuni
infection may have substantial impact on animal health and welfare in intensive poultry production
.
Engineered Endolysin-Based “Artilysins” To Combat Multidrug-Resistant Gram-Negative Pathogens
Authors: Briers Yves , Walmagh Maarten , Van Puyenbroeck Victor , Cornelissen Anneleen , Cenens William , Aertsen Abram , Oliveira Hugo , Azeredo Joana , Verween Gunther , Pirnay Jean-Paul , Miller Stefan , Volckaert Guido , Lavigne Rob 
Published: July 2014

ABSTRACT

The global threat to public health posed by emerging multidrug-resistant bacteria in the past few years necessitates the development of novel approaches to combat bacterial infections. Endolysins encoded by bacterial viruses (or phages) represent one promising avenue of investigation. These enzyme-based antibacterials efficiently kill Gram-positive bacteria upon contact by specific cell wall hydrolysis. However, a major hurdle in their exploitation as antibacterials against Gram-negative pathogens is the impermeable lipopolysaccharide layer surrounding their cell wall. Therefore, we developed and optimized an approach to engineer these enzymes as outer membrane-penetrating endolysins (Artilysins), rendering them highly bactericidal against Gram-negative pathogens, including
Pseudomonas aeruginosa
and
Acinetobacter baumannii
. Artilysins combining a polycationic nonapeptide and a modular endolysin are able to kill these (multidrug-resistant) strains
in vitro
with a 4 to 5 log reduction within 30 min. We show that the activity of Artilysins can be further enhanced by the presence of a linker of increasing length between the peptide and endolysin or by a combination of both polycationic and hydrophobic/amphipathic peptides. Time-lapse microscopy confirmed the mode of action of polycationic Artilysins, showing that they pass the outer membrane to degrade the peptidoglycan with subsequent cell lysis. Artilysins are effective
in vitro
(human keratinocytes) and
in vivo
(
Caenorhabditis elegans
).

IMPORTANCE
Bacterial resistance to most commonly used antibiotics is a major challenge of the 21st century. Infections that cannot be treated by first-line antibiotics lead to increasing morbidity and mortality, while millions of dollars are spent each year by health care systems in trying to control antibiotic-resistant bacteria and to prevent cross-transmission of resistance. Endolysins—enzymes derived from bacterial viruses—represent a completely novel, promising class of antibacterials based on cell wall hydrolysis. Specifically, they are active against Gram-positive species, which lack a protective outer membrane and which have a low probability of resistance development. We modified endolysins by protein engineering to create Artilysins that are able to pass the outer membrane and become active against
Pseudomonas aeruginosa
and
Acinetobacter baumannii
, two of the most hazardous drug-resistant Gram-negative pathogens.
Interobserver variability in the assessment of aneurysm occlusion with the WEB aneurysm embolization system
Authors: Fiorella David , Arthur Adam , Byrne James , Pierot Laurent , Molyneux Andy , Duckwiler Gary , McCarthy Thomas , Strother Charles 
Published: July 2014

ObjectiveThe WEB (WEB aneurysm embolization system, Sequent Medical, Aliso Viejo, California, USA) is a self-expanding, nitinol, mesh device designed to achieve aneurysm occlusion after endosaccular deployment. The WEB Occlusion Scale (WOS) is a standardized angiographic assessment scale for reporting aneurysm occlusion achieved with intrasaccular mesh implants. This study was performed to assess the interobserver variability of the WOS.MethodsSeven experienced neurovascular specialists were trained to apply the WOS. These physicians independently reviewed angiographic image sets from 30 patients treated with the WEB under blinded conditions. No additional clinical information was provided. Raters graded each image according to the WOS (complete occlusion, residual neck or residual aneurysm). Final statistics were calculated using the dichotomous outcomes of complete occlusion or incomplete occlusion. The interobserver agreement was measured by the generalized κ statistic.ResultsIn this series of 30 test case aneurysms, observers rated 12–17 as completely occluded, 3–9 as nearly completely occluded, and 9–11 as demonstrating residual aneurysm filling. Agreement was perfect across all seven observers for the presence or absence of complete occlusion in 22 of 30 cases. Overall, interobserver agreement was substantial (κ statistic 0.779 with a 95% CI of 0.700 to 0.857).ConclusionsThe WOS allows a consistent means of reporting angiographic occlusion for aneurysms treated with the WEB device.
Minimally invasive cone beam CT-guided evacuation of parenchymal and ventricular hemorrhage using the Apollo system: proof of concept in a cadaver model
Authors: Fiorella David , Arthur Adam , Schafer Sebastian 
Published: July 2014

IntroductionThe Apollo system (Penumbra Inc, Alameda, California, USA) is a low profile irrigation–aspiration system designed for the evacuation of intracranial hemorrhage.ObjectiveTo demonstrate the feasibility of using Apollo in combination with cone beam CT guidance.MethodsParenchymal (n=1) and mixed parenchymal–intraventricular hematomas (n=1) were created in cadaver heads using a transvascular (n=1) or transcranial (n=1) approach. Hematomas were then imaged with cone beam CT (CB-CT), and the long axis of the hematoma defined. The CB-CT data were then used to guide transcranial access to the hematoma—defining the location of the burr hole and the path to the leading edge of the hematoma. An 8F vascular sheath was then placed under live fluoroscopic guidance into the hematoma. A second CB-CT was performed to confirm localization of the sheath. The hematoma was then demarcated on the CB-CT and the Apollo wand was introduced through the 8F sheath and irrigation–aspiration was performed under (periodic) live fluoroscopic guidance. The operators manipulated the wand within the visible boundaries of the hematoma. After irrigation–aspiration, a control CB-CT was performed to document reduction in hematoma volume.ResultsTransvascular and transcranial techniques were both successful in creating intracranial hematomas. Hematomas could be defined with conspicuity sufficient for localization and volumetric measurement using CB-CT. Live fluoroscopic guidance was effective in navigating a sheath into the leading aspect of a parenchymal hematoma and guiding irrigation–aspiration with the Apollo system. Irrigation–aspiration reduced the parenchymal hemorrhage volume from 14.8 to 1.7 cc in 189 s in the first case (parenchymal hemorrhage) and from 26.4 to 4.1 cc in 300 s in the second case (parenchymal and intraventricular hemorrhage).ConclusionsThe cadaver model described is a useful means of studying interventional techniques for intracranial hemorrhage. It seems feasible to use CB-CT to guide the evacuation of intraparenchymal and intraventricular hemorrhage using the Apollo system through a minimally invasive transcranial access.
Restudy of surface tension of QGP with one-loop correction in the mean-field potential
Authors: Singh S. Somorendro , Gupta K. K. , Jha A. K. 
Published: July 2014

Surface tension of quark–gluon plasma (QGP) evolution with one-loop correction in the mean-field potential is studied. First, with the correction, the stable QGP droplet size decreases. Then, the value of surface tension is found to be improved and it approaches to the lattice value of surface tension [Formula: see text]. Moreover, the ratio of the surface tension to the cube of the critical temperature is found to increase the value in comparison to earlier studies without correction factor [R. Ramanathan, K. K. Gupta, A. K. Jha and S. S. Singh, Pram. J. Phys. 68, 757 (2007)].