bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic Analysis of PRMT1 Reveals Multifactorial Processivity and a Sequential Ordered Mechanism
Authors: Brown Jennifer I. , Koopmans Timo , van Strien Jolinde , Martin Nathaniel I. , Frankel Adam 
Published: November 2017

AbstractArginine methylation is a prevalent post‐translational modification in eukaryotic cells. Two significant debates exist within the field: do these enzymes dimethylate their substrates in a processive or distributive manner, and do these enzymes operate using a random or sequential method of bisubstrate binding? We revealed that human protein arginine N‐methyltransferase 1 (PRMT1) enzyme kinetics are dependent on substrate sequence. Further, peptides containing an Nη‐hydroxyarginine generally demonstrated substrate inhibition and had improved KM values, which evoked a possible role in inhibitor design. We also revealed that the perceived degree of enzyme processivity is a function of both cofactor and enzyme concentration, suggesting that previous conclusions about PRMT sequential methyl transfer mechanisms require reassessment. Finally, we demonstrated a sequential ordered Bi–Bi kinetic mechanism for PRMT1, based on steady‐state kinetic analysis. Together, our data indicate a PRMT1 mechanism of action and processivity that might also extend to other functionally and structurally conserved PRMTs.
Spaghetti, a homolog of human RPAP3 (RNA polymerase II‐associated protein 3), determines the fate of germline stem cells in Drosophila ovary
Authors: Chen Dongsheng , Tao Xiaoqian , Zhou Lijuan , Sun Fuling , Sun Mingzhong , Fang Xin 
Published: November 2017

AbstractThe Drosophila ovary provides an attractive model for studying the extrinsic or intrinsic factors that regulate the fate of germline stem cells (GSCs). Using this model, we identified a new role for Drosophila spaghetti (spag), encoding a homolog of human RNA polymerase II‐associated protein 3 (RPAP3), in regulating the fate of ovarian GSCs. Results from spag knockdown and genetic mosaic studies suggest that spag functions as an intrinsic factor for GSCs maintenance. Loss of Spag by, either spag RNAi or null mutation failed to trigger apoptosis in ovarian GSCs. Overexpression of spag led to negligible increases in the number of GSC/Cystoblast (CB) cells, suggesting that an excess of Spag is not sufficient to accelerate the proliferation of GSCs or delay CBs’ differentiation. Our study provides evidence supporting that spag is involved in adult stem cells maintenance. In addition, the RNAi screen results showed that knockdown of Hsp90, one of known Spag interacting partners, led to loss of ovarian GSCs in Drosophila. Heterozygous mutations in hsp90 (hsp90/+) dramatically accelerated the GSC loss in spag RNAi ovaries, suggesting that the Spag‐contained complex possibly plays an essential role in controlling the GSCs fate.
Low‐Valent Ate Complexes Formed in Cobalt‐Catalyzed Cross‐Coupling Reactions with 1,3‐Dienes as Additives
Authors: Kreyenschmidt Friedrich , Koszinowski Konrad 
Published: November 2017

AbstractThe combination of CoCl2 and 1,3‐dienes is known to catalyze challenging alkyl–alkyl cross‐coupling reactions between Grignard reagents and alkyl halides, but the mechanism of these valuable transformations remains speculative. Herein, electrospray‐ionization mass spectrometry is used to identify and characterize the elusive intermediates of these and related reactions. The vast majority of detected species contain low‐valent cobalt(I) centers and diene molecules. Charge tagging, deuterium labeling, and gas‐phase fragmentation experiments elucidate the likely origin of these species and show that the diene not only binds to Co as a π ligand, but also undergoes migratory insertion reactions into Co−H and Co−R bonds. The resulting species have a strong tendency to form anionic cobalt(I) ate complexes, the superior nucleophilicity of which should render them highly reactive toward electrophilic substrates and, thus, presumably is the key to the high catalytic efficiency of the system under investigation. Upon the reaction of the in situ formed cobalt(I) ate complexes with organyl halides, only the final cross‐coupling product could be detected, but no cobalt(III) species. This finding implies that this reaction step proceeds in a direct manner without any intermediate or, alternatively, that it involves an intermediate with a very short lifetime.
Production of (R)‐1‐(1,3‐benzodioxol‐5‐yl)ethanol in high enantiomeric purity by Lactobacillus paracaseiBD101
Authors: Şahin Engin 
Published: November 2017

AbstractPiperonyl ring is found in a number of naturally occurring compounds and possesses enormous biological activities. There are many studies in the literature with compounds containing a piperonyl ring, but there are very few studies on the synthesis of chiral piperonyl carbinol. The objective of this study was to determine the microbial reduction ability of bacterial strains and to reveal the effects of different physicochemical parameters on this reduction ability. A total of 15 bacterial isolates were screened for their ability to reduce 1‐(benzo[d][1,3]dioxol‐5‐yl) ethanone 1 to its corresponding alcohol. Among these isolates Lactobacillus paracasei BD101 was found to be the most successful biocatalyst to reduce the ketone containing piperonyl ring to the corresponding alcohol. The reaction conditions were systematically optimized for the reducing agent L paracasei BD101, which showed high enantioselectivity and conversion for the bioreduction. The preparative scale study was performed, and a total of 3.72 g of (R)‐1‐(1,3‐benzodioxol‐5‐yl) ethanol in high enantiomeric form (>99% enantiomeric excess) was produced in a mild, cheap, and environment‐friendly process. This study demonstrates that L paracasei BD101 can be used as a biocatalyst to obtain chiral carbinol with excellent yield and selectivity.
Live Cell Labeling with Terpyridine Derivative Proligands to Measure Cytotoxicity Mediated by Immune Cells
Authors: Sakai Yuki , Mizuta Satoshi , Kumagai Asuka , Tagod Mohammed S. O. , Senju Hiroaki , Nakamura Tatsufumi , Morita Craig T. , Tanaka Yoshimasa 
Published: November 2017

AbstractImmunotherapy using immune checkpoint inhibitors and CAR‐T cells has revolutionized treatment for patients with malignant tumors. However, measuring tumor cell cytotoxicity mediated by immune effector cells in clinical laboratories has been difficult due to the requirement for radioactive substances. In this study, a series of novel terpyridine derivative proligands were synthesized, and a non‐radioactive cellular cytotoxicity assay using the newly synthesized compounds was developed for use in preclinical and clinical studies for cancer immunotherapy. Once internalized into target cells, the compounds are hydrolyzed by esterases, resulting in the intracellular accumulation of the negatively charged terpyridine derivatives. When the labeled target cells are recognized and killed by immune effector cells, the integrity of the cell membrane is disrupted, and the terpyridine derivatives are released. Upon combining the culture supernatant with europium (Eu3+), the cytotoxicity of immune effector cells for the target cells can be quantitatively determined by measuring the intensity of the Eu3+/ligand‐derived time‐resolved fluorescence. Thus, the assay developed in this study would facilitate the development of novel cancer immunotherapies.
Preparing and Presenting a Talk
Authors: More Michael , Sjolander Christine , Chang Stephen 
Published: November 2017

AbstractHow information is presented can have as much impact as the information itself. In order to ensure that you're getting your message across to the audience, you need to prepare your talk with as much care as you designed your research. This unit outlines information on how to prepare a great talk and deliver it for maximum effectiveness. © 2017 by John Wiley & Sons, Inc.
Dictyostelium discoideum: A Model System for Cell and Developmental Biology
Authors: Mathavarajah Sabateeshan , Flores Ana , Huber Robert J. 
Published: November 2017

AbstractThe social amoeba Dictyostelium discoideum has long served as a model system for studying fundamental processes in cell and developmental biology. This eukaryotic microbe is also recognized as a model organism for biomedical and human disease research since the genome encodes homologs of genes linked to human disease, such as those linked to cancer and neurodegeneration. Dictyostelium has a unique life cycle composed of a unicellular growth phase and a multicellular developmental phase that is induced by starvation. During its life cycle, Dictyostelium undergoes conserved cellular processes including, but not limited to, cell proliferation, phagocytosis, intercellular signaling, cell adhesion and motility, chemotaxis, and cell differentiation. The history of the organism, the resources available to researchers in the community, and the diverse ways that Dictyostelium is used in the contemporary research lab are discussed. © 2017 by John Wiley & Sons, Inc.
Culture of Escherichia coli and Related Bacteria
Authors: Riley Sean P. , Woodman Michael E. , Holt Jonathan , Stevenson Brian 
Published: November 2017

AbstractThis appendix provides general techniques, equipment, and media used for the growth of many commonly encountered bacteria. For specific growth conditions, readers should refer to units regarding the laboratory maintenance of the organism of interest. © 2017 by John Wiley & Sons, Inc.
WtF‐Nano: One‐Pot Dewatering and Water‐Free Topochemical Modification of Nanocellulose in Ionic Liquids or γ‐Valerolactone
Authors: Laaksonen Tiina , Helminen Jussi K. J. , Lemetti Laura , Långbacka Jesper , Rico del Cerro Daniel , Hummel Michael , Filpponen Ilari , Rantamäki Antti H. , Kakko Tia , Kemell Marianna L. , Wiedmer Susanne K. , Heikkinen Sami , Kilpeläinen Ilkka , King Alistair W. T. 
Published: November 2017

AbstractIonic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water‐free topochemical modification of the nanocellulose (a process denoted as “WtF‐Nano”). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co‐solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non‐dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide‐angle X‐ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1 D and 2 D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters.
Cumulative and partially recoverable impacts of nitrogen addition on a temperate steppe
Authors: Hao Tianxiang , Song Ling , Goulding Keith , Zhang Fusuo , Liu Xuejun 
Published: November 2017

AbstractAtmospheric nitrogen (N) deposition has been shown to decrease biodiversity and change nutrient cycles in terrestrial ecosystems. However, our understanding of ecological responses to chronic N addition and ecological recovery of grassland from N enrichment is limited. Here we present evidence from an 11‐year grassland experiment with a range of N addition rates (0, 30, 60, 120, 240, and 480 kg N·ha−1·yr−1) in Inner Mongolia, China. Chronic N addition led to a reduction in species richness, Shannon diversity index, and soil pH and an increase in aboveground biomass, foliar N, and soil mineral N. High N addition rates (240 and 480 kg N·ha−1·yr−1) showed significant effects in the first and second years, which stabilized over time. Nitrogen addition at low rates (30 and 60 kg N·ha−1·yr−1) took longer (e.g., three years or more) to achieve significant effects. The negative impacts of high N addition (480 kg N·ha−1·yr−1) were reduced and species richness, Shannon diversity index, and soil pH showed a limited but rapid recovery with the cessation of N addition. Our findings suggest serious and cumulative impacts of N addition on plant and soil communities but the potential for partial system recovery over time if N inputs decline or cease.
Local and regional stressors interact to drive a salinization‐induced outbreak of predators on oyster reefs
Authors: Kimbro David L. , White J. Wilson , Tillotson Hanna , Cox Nikkie , Christopher Megan , Stokes‐Cawley Owen , Yuan Samantha , Pusack Timothy J. , Stallings Christopher D. 
Published: November 2017

AbstractPredator outbreaks are predicted to increasingly decimate economically and ecologically important prey populations because global climate change and food‐web modifications frequently facilitate predators and stress prey. Natural systems are organized hierarchically, with processes operating at multiple scales giving rise to patterns of biodiversity, so predicting and managing outbreaks requires a framework that accounts for the effects of both local and regional stressors. Here, we used the comparative experimental approach to investigate whether the collapse of a nationally important oyster fishery in the Gulf of Mexico (Apalachicola Bay, Florida) could have been (1) caused proximally by a predator outbreak and (2) whether this outbreak was mediated by local‐ and/or regional‐scale forces. During the fishery collapse, we paired experiments with monitoring in Apalachicola Bay and found elevated water salinity, high abundance of predatory snails, and intense oyster mortality due to predation. By repeating these experiments over 4 yr, we found that periods of reduced water salinity inhibited predation on oysters. To partition the influence of local‐versus‐regional factors on this predator outbreak, we simultaneously replicated the paired experiments and monitoring in a nearby bay (Ochlockonee Bay) that shares the same regional‐scale rainfall conditions. Increasing freshwater withdrawals from the watershed that drains into Apalachicola Bay have increased salinities in that bay, but there have not been similar withdrawals in the Ochlockonee Bay watershed. Therefore, Apalachicola Bay experienced a localized anthropogenic stress, while both bays experienced regional stress from drought. In Ochlockonee Bay, our experiments demonstrated that the river maintained sufficiently low salinity to provide ~50% of oyster reefs with a refuge from predation. In contrast, salinity‐dependent predation in Apalachicola Bay extended up to the river mouth. Given the stark differences in upstream water withdrawals between these watersheds, it is reasonable to surmise that these withdrawals exacerbated the stress of regional drought, created the difference in predation between the two bays, and thus may have precipitated the oyster fishery collapse. Our study provides empirical support for recent theory about the hierarchical organization of ecosystems, which predicts that stressors will interact across scales to cause localized predator outbreaks.
Habitat selection differs across hierarchical behaviors: selection of patches and intensity of patch use
Authors: McMahon Laura A. , Rachlow Janet L. , Shipley Lisa A. , Forbey Jennifer S. , Johnson Timothy R. 
Published: November 2017

AbstractWhen animals select habitats, they integrate a suite of behaviors that are influenced by multiple competing resource requirements. Resources that influence decisions about habitat use are likely to differ across spatial scales and hierarchical behaviors. At coarser scales, animals are expected to select resources that are critical to fitness, and at finer scales, to intensively use resources that enhance fitness. Our goal was to contrast habitat selection at two hierarchical behavioral levels (patch selection and intensity of patch use) to test hypotheses about how resources shape habitat use. We applied a two‐stage hurdle model to quantify both initial selection and intensity of use of resource patches by a burrowing herbivore, the pygmy rabbit (Brachylagus idahoensis). We expected security from predation to influence initial selection of patches, and forage availability to influence intensity of use of selected patches. We monitored locations of adults fitted with radio‐collars during winter and summer. We measured vegetation, burrow characteristics, and concealment cover within patches that were used and unused by rabbits, and we quantified burrow densities surrounding patches in a GIS. Selection of used patches from available patches was largely influenced by security resources (presence and proximity of burrows, shrub height, and woody ground cover) during both seasons. Intensity of patch use was also influenced by forage availability and, consequently, differed between seasons. During winter, sagebrush is the primary forage, and greater sagebrush canopy within a patch was associated with increased intensity of use. During summer, rabbits more intensively used patches with greater availability of herbaceous forage. Elucidating how animals make choices about habitats across a diversity of spatial and temporal scales will continue to increase our understanding of the factors that govern distribution of populations and movements of individuals. By extending these concepts to hierarchical behaviors, we can enhance insights into the processes that shape the patterns of habitat use we observe.
Highly Selective and Active Pd‐In/three‐dimensional Graphene with Special Structure for Electroreduction CO2 to Formate
Authors: He Guangya , Tang Hanyu , Wang Hui , Bian Zhaoyong 
Published: November 2017

AbstractElectrocatalytic reduction of CO2 to formate on carbon based electrodes is known to suffer from low electrochemical reaction activity and product selectivity. Pd/three‐dimensional graphene (Pd/3D‐RGO), In/3D‐RGO and Pd‐In/3D‐RGO for the electrochemical reduction of CO2 were prepared by a mild method that combines chemical and hydrothermal. The metal/3D‐graphenes (metal/3D‐RGO) were characterized by scanning electron microscopy, X‐ray diffraction, transmission electron microscopy and X‐ray photoelectron spectroscopy (XPS). Cyclic voltammetry and the ion chromatography were performed to investigate the electrochemical performance of the metal/3D‐RGO. The morphology and dispersion of metal/3D‐RGO are 3D structure with amount of interconnected pores with metal NPs loading on the fold. And the Pd0.5‐In0.5/3D‐RGO show excellent surface performance with well dispersion and smallest particle size (12.8 nm). XPS reveal that binding energy of Pd (In) NPs is shifted to negative energy, for the metal lose electrons in metal and combine with C, which is demonstrated in the HNO3 experiment. The peak potential of Pd0.5‐In0.5/3D‐RGO is −0.70 V (vs. Ag/AgCl), which is more positive than In1.0/3D‐RGO (−0.73 V) and Pd1.0/3D‐RGO (−1.2 V). The highest faradaic efficiency (85.3 %) happens in Pd0.5‐In0.5/3D‐RGO at −1.6 V vs. Ag/AgCl. In these experiments, the special structure that metal NPs combine with C and the bimetal NPs give a direction to convert CO2 to formate.
Solar Landfills: Economic, Environmental, and Social Benefits
Authors: Ciriminna Rosaria , Albanese Lorenzo , Pecoraino Mario , Meneguzzo Francesco , Pagliaro Mario 
Published: November 2017

AbstractIdeally suited for hosting large solar photovoltaic arrays feeding electricity into the grid, closed landfills will play a significant role in the undergoing energy transition from fossil‐fuel and nuclear energy to renewable energy. Aimed at sustainability scholars and policy makers, this study identifies the economic, environmental, and social benefits of solar landfills, suggesting avenues for the massive transformation of hazardous landfills into renewable‐energy‐generation plants. Thus, the landfills no longer pose threats to human health and to the ecosystem.
Lithological controls on hillslope sediment supply: insights from landslide activity and grain size distributions
Authors: Roda‐Boluda Duna C. , D'Arcy Mitch , McDonald Jordan , Whittaker Alexander C. 
Published: November 2017

AbstractThe volumes, rates and grain size distributions of sediment supplied from hillslopes represent the initial input of sediment delivered from upland areas and propagated through sediment routing systems. Moreover, hillslope sediment supply has a significant impact on landscape response time to tectonic and climatic perturbations. However, there are very few detailed field studies characterizing hillslope sediment supply as a function of lithology and delivery process. Here, we present new empirical data from tectonically‐active areas in southern Italy that quantifies how lithology and rock strength control the landslide fluxes and grain size distributions supplied from hillslopes. Landslides are the major source of hillslope sediment supply in this area, and our inventory of ~2800 landslides reveals that landslide sediment flux is dominated by small, shallow landslides. We find that lithology and rock strength modulate the abundance of steep slopes and landslides, and the distribution of landslide sizes. Outcrop‐scale rock strength also controls the grain sizes supplied by bedrock weathering, and influences the degree of coarsening of landslide supply with respect to weathering supply. Finally, we show that hillslope sediment supply largely determines the grain sizes of fluvial export, from catchments and that catchments with greater long‐term landslide rates deliver coarser material. Therefore, our results demonstrate a dual control of lithology on hillslope sediment supply, by modulating both the sediment fluxes from landslides and the grain sizes supplied by hillslopes to the fluvial system. Copyright © 2017 John Wiley & Sons, Ltd.
Dating lava flows of tropical volcanoes by means of spatial modeling of vegetation recovery
Authors: Li Long , Bakelants Lien , Solana Carmen , Canters Frank , Kervyn Matthieu 
Published: November 2017

AbstractThe age of past lava flows is crucial information for evaluating the hazards and risks posed by effusive volcanoes, but traditional dating methods are expensive and time‐consuming. This study proposes an alternative statistical dating method based on remote sensing observations of tropical volcanoes by exploiting the relationship between lava flow age and vegetation cover. First, the factors controlling vegetation density on lava flows, represented by the normalized difference vegetation index (NDVI), were investigated. These factors were then integrated into pixel‐based multi‐variable regression models of lava flow age to derive lava flow age maps. The method was tested at a pixel scale on three tropical African volcanoes with considerable recent effusive activity: Nyamuragira (Democratic Republic of Congo), Mt Cameroon (Cameroon) and Karthala (the Comoros). Due to different climatic and topographic conditions, the parameters of the spatial modeling are volcano‐specific. Validation suggests that the obtained statistical models are robust and can thus be applied for estimating the age of unmodified undated lava flow surfaces for these volcanoes. When the models are applied to fully vegetated lava flows, the results should be interpreted with caution due to the saturation of NDVI. In order to improve the accuracy of the models, when available, spatial data on temperature and precipitation should be included to directly represent climatic variation. Copyright © 2017 John Wiley & Sons, Ltd.