bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bmp signaling is necessary and sufficient for ventrolateral endoderm specification in Xenopus
Authors: Wills Andrea , Dickinson Kari , Khokha Mustafa , Baker Julie C. 
Published: July 2008

AbstractHere we show that Bmp signaling is necessary and sufficient for the specification of ventral endoderm in Xenopus embryos. Overexpression of Bmp4 in ectoderm induces markers of endoderm, including Sox17β, Mixer, and VegT, but cannot induce the expression of the dorsoanterior markers, Xhex and Cerberus. Furthermore, knockdown approaches using overexpression of Bmp antagonists and morpholinos designed against Bmp4, Bmp2, and Bmp7 demonstrate that Bmp signaling is critical for ventral, but not dorsoanterior endoderm formation. This activity is not simply a result of embryonic dorsalization as markers for dorsal endoderm are not expanded. We further show that endodermal cells of either ventral or dorsal character do not form when both Wnt and Bmp signals are abolished. Overall, this report strongly suggests that Bmp plays an essential role in ventral endoderm specification. Developmental Dynamics 237:2177–2186, 2008. © 2008 Wiley‐Liss, Inc.
Lifespan extension and increased pumping rate accompany pharyngeal muscle‐specific expression of nfi‐1 in C. elegans
Authors: Lazakovitch Elena , Kalb John M. , Gronostajski Richard M. 
Published: July 2008

AbstractCaenorhabditis elegans nfi‐1 belongs to the Nuclear Factor I (NFI) family of transcription factors known to regulate metazoan gene expression and development. We showed previously that loss of nfi‐1 in worms results in multiple behavioral defects; slower pharyngeal pumping rate, impaired egg laying, defective motility, and a shortened life span. Here, we generated cell‐type specific transgenic worms to determine the cells in which nfi‐1 must be expressed to rescue the pharyngeal pumping defect. Expression of nfi‐1 from the pharyngeal muscle‐specific myo‐2 promoter, but not from the F25B3.3 or myo‐3 promoters, rescued the pharyngeal pumping defect of nfi‐1 worms. Surprisingly, myo‐2‐driven nfi‐1 expression also rescued the shortened lifespan of nfi‐1 worms, demonstrating a possible cell‐autonomous role of nfi‐1 in pharyngeal muscle for both phenotypes. We propose some relationships between the pharyngeal pumping and lifespan phenotypes and potential mechanisms of nfi‐1 function. Developmental Dynamics 237:2100–2107, 2008. © 2008 Wiley‐Liss, Inc.
Developmental alveolarization of the mouse lung
Authors: Mund Sonja I. , Stampanoni Marco , Schittny Johannes C. 
Published: July 2008

AbstractPostnatal lung development is not well characterized in mice, especially the time point when alveolarization is completed. Using the total length and the length density of the free septal edge as measured for the formation of new septa, we followed alveolarization throughout postnatal lung development (days 2–125). Furthermore, the alveolar surface area was estimated. The formation of new septa was observed until day 36. Approximately 10% of the septa present in adult mice were formed prenatally by branching morphogenesis, ∼50% were generated postnatally before and ∼40% after maturation of the alveolar microvasculature. Approximately 5% of the alveolar surface area present during adulthood was present before alveolarization started, ∼55% was formed during alveolarization (days 4–36) and ∼40% afterward due to growth processes. We conclude that alveolarization continues until young adulthood and that the maturation of the alveolar microvasculature does not preclude further alveolarization. Developmental Dynamics 237:2108–2116, 2008. © 2008 Wiley‐Liss, Inc.
Fishing lines, time‐delayed guideposts, and other tricks used by developing pharyngeal neurons in Caenorhabditis elegans
Authors: Pilon Marc 
Published: July 2008

AbstractThe 20 neurons that innervate the Caenorhabditis elegans pharynx form a simple nervous system that develops and operates in near complete isolation from the rest of the worm body and, therefore, offers a manageable degree of complexity for developmental genetics studies. This review discusses the progress that has been made in determining the mechanisms by which 4 of the 20 pharyngeal neurons develop, and emphasizes surprising processes that add to the classic growth cone guidance model which is usually thought to explain how most axons establish their trajectories. Developmental Dynamics 237:2073–2080, 2008. © 2008 Wiley‐Liss, Inc.
Identification and characterization of the porcine (Sus scrofa) survival motor neuron (SMN1) gene: An animal model for therapeutic studies
Authors: Lorson Monique A. , Spate Lee D. , Prather Randall S. , Lorson Christian L. 
Published: July 2008

AbstractSpinal muscular atrophy (SMA) is an autosomal recessive disorder that is characterized by the degeneration of the motor neurons of the spinal cord leading to muscle atrophy. SMA is a result of a loss‐of‐function of the gene survival motor neuron‐1 (SMN1). We have chosen to generate a transgenic swine model of SMA for the development and testing of therapeutics and evaluation of toxicology. To this end, we report the first cloning and identification of the swine SMN1 gene and show that there is significant sequence homology between swine and human SMN throughout the coding region. Reverse transcriptase‐polymerase chain reaction results demonstrated slight changes in SMN RNA expression during development and in different tissues. In contrast, protein expression profiles were dramatically different based upon different tissues and developmental stages, consistent with human SMN expression. Porcine SMN localization is consistent with human SMN, localizing diffusely within the cytoplasm and in punctate nuclear structures characteristic of nuclear gems. Importantly, transient transfection of porcine SMN1 in 3813 SMA type 1 fibroblasts demonstrate that porcine SMN1 can rescue the deficiency of SMN protein and gem formation in these cells. These studies provide the first characterization of the porcine SMN1 gene and SMN protein and suggest that a transgenic swine SMA model is feasible. Developmental Dynamics 237:2268–2278, 2008. © 2008 Wiley‐Liss, Inc.
Role for ephrinB2 in postnatal lung alveolar development and elastic matrix integrity
Authors: Wilkinson George A. , Schittny Johannes C. , Reinhardt Dieter P. , Klein Rüdiger 
Published: July 2008

AbstractAlveoli are formed in the lung by the insertion of secondary tissue folds, termed septa, which are subsequently remodeled to form the mature alveolar wall. Secondary septation requires interplay between three cell types: endothelial cells forming capillaries, contractile interstitial myofibroblasts, and epithelial cells. Here, we report that postnatal lung alveolization critically requires ephrinB2, a ligand for Eph receptor tyrosine kinases expressed by the microvasculature. Mice homozygous for the hypomorphic knockin allele ephrinB2ΔV/ΔV, encoding mutant ephrinB2 with a disrupted C‐terminal PDZ interaction motif, show severe postnatal lung defects including an almost complete absence of lung alveoli and abnormal and disorganized elastic matrix. Lung alveolar formation is not sensitive to loss of ephrinB2 cytoplasmic tyrosine phosphorylation sites. Postnatal day 1 mutant lungs show extracellular matrix alterations without differences in proportions of major distal cell populations. We conclude that lung alveolar formation relies on endothelial ephrinB2 function. Developmental Dynamics 237:2220–2234, 2008. © 2008 Wiley‐Liss, Inc.
Spectroscopic and Computational Study on New Blue Emitting ReL(CO)3Cl Complexes Containing Pyridylimidazo[1,5‐a]pyridine Ligands (Eur. J. Inorg. Chem. 23/2008)
Authors: Garino Claudio , Ruiu Tiziana , Salassa Luca , Albertino Andrea , Volpi Giorgio , Nervi Carlo , Gobetto Roberto , Hardcastle Kenneth I. 
Published: July 2008

AbstractThe cover picture shows a representation of the mixed theoretical and experimental method employed by inorganic chemists in the study of structural and photophysical properties of luminescent molecules. The combination of time‐dependent density functional theory and spectroscopy is crucial for determining the nature of excited states in metal complexes and thus their absorption and emission features. New dual‐emitting ReL(CO)3Cl complexes and their 1‐(2‐pyridyl)imidazo[1,5‐a]pyridine ligands were successfully studied by using such a hybrid approach. Details are discussed in the Short Communication by R. Gobetto et al. on p. 3587 ff.
Enzymatic interesterification of olive oil with fully hydrogenated palm oil: Characterization of fats
Authors: Criado Manuel , Hernández‐Martín Estela , López‐Hernández Arnoldo , Otero Cristina 
Published: July 2008

AbstractSeven different reaction products were prepared via enzymatic interesterification of extra‐virgin olive oil (EVOO) and fully hydrogenated palm oil (FHPO), by varying the initial weight ratio of EVOO to FHPO from 80 : 20 to 20 : 80. The chemical, physical and functional properties of both the semi‐solid reaction products and the corresponding physical blends of the precursor starting materials were characterized. Fats prepared using large proportions of FHPO contained high levels of TAG species containing only saturated fatty acid residues. By contrast, high levels of TAG species containing both saturated and unsaturated fatty acid residues were found in fat products obtained with the lowest proportions of FHPO. Independently of the initial weight ratio of EVOO to FHPO, the interesterified products were characterized by a higher molar ratio of unsaturated to saturated fatty acid residues at the sn‐2 position, were softer over a wide temperature range, exhibited lower oxidative stabilities and were completely melted at lower temperatures than the corresponding physical blends. Potential applications of the reaction products range from margarines (highest weight ratios of EVOO to FHPO) to frying fats (lowest weight ratios of EVOO to FHPO).
Docosahexaenoic acid: Nutrient and precursor of bioactive lipids
Authors: Lagarde Michel 
Published: July 2008

AbstractDocosahexaenoic acid (DHA), the end‐product of the n‐3 family fatty acid, is an abundant component in the brain phospholipids, and a major nutrient of marine lipids. It is accumulated in this compartment from the non‐esterified pool bound to blood plasma albumin. 1‐Lyso,2‐DHA‐glycerophosphocholine is another form, also bound to albumin, which appears even more efficient than non‐esterified DHA for its brain accretion. DHA, as a highly unsaturated fatty acid, may affect the cell redox status. As expected, it may promote lipid peroxidation at high concentrations, but most interestingly may prevent it at low concentrations. DHA is also a fairly good substrate of lipoxygenases, especially the n‐9 and n‐6 ones. Hydroxy derivatives, i.e., docosanoids, exhibit potent biological activities, which may explain part of the potential benefit of DHA in the brain and vascular bed.
Indium‐Promoted Acyloxyallylation Reaction of Azetidine‐2,3‐diones in Aqueous Media: A New Route to Densely Functionalized 3‐Substituted 3‐Hydroxy‐β‐lactams
Authors: Alcaide Benito , Almendros Pedro , Aragoncillo Cristina , Cabrero Gema , Callejo Ricardo , Pilar Ruiz M. 
Published: July 2008

AbstractDensely functionalized 3‐substituted 3‐hydroxy‐β‐lactams have been obtained by acyloxyallylation reaction of azetidine‐2,3‐diones with 3‐bromopropenyl acetate or benzoate in aqueous media promoted by indium under Barbier conditions. Two new stereocenters were formed; the stereochemistry at the new C‐3 quaternary center was fully controlled by placing a bulky chiral substituent at C‐4. However, poor diastereoselectivities were observed in the new allylicstereocenter formed (up to 58 % de).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Biomimetic Self‐Assembly of Tetrapeptides into Fibrillar Networks and Organogels
Authors: Iqbal Sajid , Miravet Juan F. , Escuder Beatriu 
Published: July 2008

AbstractThe self‐assembly features of a family of tetrapeptides with a silk‐inspired structure are presented. An exhaustive study of the influence of the terminal alkyl chain length in this process is undertaken. Scanning electron microscopy (SEM), wide‐angle X‐ray diffraction (WAXD), FTIR spectroscopy, and circular dichroism were used for structural analysis. These compounds, as in the natural model, self‐assemble into antiparallel β‐sheet structures that further organize to form fibrillar aggregates. Furthermore, some of them arecapable of forming a crowded network that entraps thesolvent leading to physical gels with different microscopic morphologies. A model for the assembly process is proposed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Catalytic Asymmetric Alkylation of Aldehydes by Using Trialkylboranes
Authors: Ukon Takahiro , Harada Toshiro 
Published: July 2008

AbstractTriethylborane can be used in the asymmetric alkylation of aldehydes by using a 3‐(3,5‐diphenylphenyl)‐H8‐BINOL‐derived titanium(IV) catalyst in the presence of an excess amount of titanium tetraisopropoxide. The reaction proceeds with a low catalyst loading (2 mol‐%), exhibiting high enantioselectivity for aromatic and unsaturated aldehydes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Recent Advances in the Chemistry of Aminocyclitols (Eur. J. Org. Chem. 23/2008)
Authors: Delgado Antonio 
Published: July 2008

AbstractThe cover picture shows three different approaches to the synthesis of aminocyclitols. Aminocyclitols are found as structural components of several families of natural products with different biological properties. Several synthetic strategies for this kind of compounds have been devised over the last years. Interestingly, some synthetic aminocyclitols show interesting properties as glucosidase inhibitors. This is the case for voglibose, a drug marketed as an oral antidiabetic drug and whose three‐dimensional structure is shown in the background. Details are presented in the Microreview by A. Delgado on p. 3893 ff.
Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon
Authors: Street‐Perrott F. Alayne , Barker Philip A. 
Published: July 2008

AbstractOn geological time‐scales (≥106 years), the global geochemical cycles of carbon and silicon are coupled by the drawdown of atmospheric CO2 through chemical weathering of Ca‐ and Mg‐silicate minerals in continental rocks. Rivers transport the soluble products of weathering (cations, alkalinity and silicic acid) to the oceans, where they are utilized by marine ecosystems. On decadal to glacial–interglacial time‐scales, however, large biotic fluxes and storages of Si within terrestrial and freshwater ecosystems need to be taken into account. Recent studies have emphasized the importance of Si‐accumulating plants, which deposit significant amounts of amorphous hydrated silica in their tissues as opal phytoliths. These include grasses, sedges, palms, some temperate deciduous trees and conifers, and many tropical hardwoods. Landscapes dominated by accumulator plants, such as tropical rainforests, grasslands, herbaceous wetlands and bamboo forests, act as ‘silica factories’. Important ‘silica bioengineers’ in freshwater ecosystems comprise diatoms, sponges and chrysophytes. This paper reviews the biological role of Si in higher plants, the impact of vegetation on rates of chemical weathering, the fluxes of Si through catchment ecosystems, lakes and rivers, and the potential contribution of new geochemical and isotopic tracers to Si biogeochemistry. Multiproxy investigations of lake sediments will provide novel insights into past variations in Si biocycling from terrestrial to aquatic realms on 10–106 year time‐scales. Copyright © 2008 John Wiley & Sons, Ltd.
Alluvial responses to the changing Earth system
Authors: Macklin Mark G. , Lewin John 
Published: July 2008

AbstractAlluvial systems are complex, self‐organizing and hierarchical in structure. They represent stored and transitory sediment bodies transported by rivers that have eroded their catchments and created multiscalar landforms and sedimentary architectures over a range of time‐scales. The central question we address in this paper is how environmental signals are autogenically processed and recorded by the fluvial sediment system. We compare databases of alluvial units that are well constrained in terms of dating control with direct or proxy records of environmental change. River system responses to environmental change are evaluated over three nested time periods spanning the past 200 000 years. First, focusing on Mediterranean European and African catchments, river responses to relatively abrupt and short‐term Late Pleistocene Dansgaard–Oeschger and Heinrich climate events are examined. Second, the effects of rapid and globally significant episodes of Holocene climate change on European rivers, together with anthropogenic land‐use impacts, are assessed. Last, ‘Little Ice Age’ flooding and alluvial responses to modern climate warming are reviewed with particular reference to upland Britain. These studies are shown to have significant implications for modelling local, regional and global‐scale alluvial responses to future environmental change. They highlight the necessity for numerical simulation models to be fully informed by field‐based knowledge and understanding of the memory effects of whole fluvial sediment systems, particularly those that have experienced repeated phases of environmental change. Copyright © 2008 John Wiley & Sons, Ltd.
Human interactions with the Earth system: people and pixels revisited
Authors: Liverman Diana M. , Cuesta Rosa Maria Roman 
Published: July 2008

AbstractThe human use of the land is one of the critical links between people and the Earth system, with changes in land use contributing to the significant modification of hydrology, ecology, geomorphology, climate and biogeochemical cycles. Over the past decade there have been several major research efforts (e.g. IGBP‐IHDP LUCC, ESSP) to link the social and natural sciences through the study of land‐use and land‐cover change, with particular attention being paid to the potential of linking remote sensing with socioeconomic data, local case studies with larger scale modelling efforts, and scientific research with the needs of stakeholders. This paper evaluates the extent to which such land‐use‐change studies can provide reliable data, explanation and projections of future land use. It assesses how such studies might address major theoretical questions in social and natural science such as those concerning the role of population or of institutions in land‐use dynamics, or the detailed attribution of hazards to physical or social processes. In general, and using examples of research conducted in Mexico, the paper concludes that progress has been limited, because of factors that include the difficulties in gathering socio‐economic information at global and regional scales, linking social data to satellite imagery, and forecasting human activities and policies. For interactions between the social and earth sciences to succeed, a certain level of tolerance and mutual understanding will be needed so that social scientists understand the earth science aspiration for quantitative socio‐economic scenarios and predictions, and earth scientists understand the variations in how social scientists explain human behaviour and institutions and accept the clear limits to predicting human activities and decisions. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of earthquake and cyclone sequencing on landsliding and fluvial sediment transfer in a mountain catchment
Authors: Lin Guan‐Wei , Chen Hongey , Hovius Niels , Horng Ming‐Jame , Dadson Simon , Meunier Patrick , Lines Max 
Published: July 2008

AbstractPatterns and rates of landsliding and fluvial sediment transfer in mountain catchments are determined by the strength and location of rain storms and earthquakes, and by the sequence in which they occur. To explore this notion, landslides caused by three tropical cyclones and a very large earthquake have been mapped in the Chenyoulan catchment in the Taiwan Central Range, where water and sediment discharges and rock strengths are well known. Prior to the MW 7·6 Chi‐Chi earthquake in 1999, storm‐driven landslide rates were modest. Landslides occurred primarily low within the landscape in shallow slopes, reworking older colluvial material. The Chi‐Chi earthquake caused wide‐spread landsliding in the steepest bedrock slopes high within the catchment due to topographic focusing of incoming seismic waves. After the earthquake landslide rates remained elevated, landslide patterns closely tracking the distribution of coseismic landslides. These patterns have not been strongly affected by rock strength. Sediment loads of the Chenyoulan River have been limited by supply from hillslopes. Prior to the Chi‐Chi earthquake, the erosion budget was dominated by one exceptionally large flood, with anomalously high sediment concentrations, caused by typhoon Herb in 1996. Sediment concentrations were much higher than normal in intermediate size floods during the first 5 years after the earthquake, giving high sediment yields. In 2005, sediment concentrations had decreased to values prevalent before 1999. The hillslope response to the Chi‐Chi earthquake has been much stronger than the five‐fold increase of fluvial sediment loads and concentrations, but since the earthquake, hillslope sediment sources have become increasingly disconnected from the channel system, with 90 per cent of landslides not reaching into channels. Downslope advection of landslide debris associated with the Chi‐Chi earthquake is driven by the impact of tropical cyclones, but occurs on a time‐scale longer than this study. Copyright © 2008 John Wiley & Sons, Ltd.
Science, systems and geomorphologies: why LESS may be more
Authors: Richards Keith , Clifford Nicholas 
Published: July 2008

AbstractThis paper has been stimulated by a debate triggered by the then British Geomorphological Research Group (now the British Society for Geomorphology) about the connections between geomorphology and Earth system science (ESS). Its purpose is to expand on some arguments we have already made about these connections, amongst other things drawing attention to neglected historical antecedents, and to the questionable status of the science implied by ESS. A premise of this further paper is that such a debate cannot be assumed to mirror conventional assessments of the content of a science, since it is about scientific institutional structures, names, boundaries and relationships. This implies that the terms of reference go well beyond critical scientific appraisal, extending to matters of evaluating a social organization, and to politics, policies, purposes and practices. We therefore begin by considering the sociology of science, scientific knowledge and technology, before moving to a consideration of the historical relationship amongst geomorphology, geology and physical geography; and to some perspectives this might offer for the current debate. Epistemological issues, arising both from the use of systems theory over multiple spatial and temporal scales, and from the demands of contemporary environmental science, are then introduced, and these lead to a conclusion that geomorphology might more appropriately be assessed against (or seen as part of) a more locally orientated ESS, which we term LESS. Copyright © 2008 John Wiley & Sons, Ltd.