bluuebunny/crossref_metadata_2025 huggingface dataset:
Dependence of field driven domain wall velocity on cross-sectional area in Ni65Fe20Co15 nanowires
Authors: Moriya Rai , Hayashi Masamitsu , Thomas Luc , Rettner Charles , Parkin Stuart S. P.
Published: October 2010

The velocity of vortex domain walls (DWs) was measured versus magnetic field in Ni65Fe20Co15 nanowires with different widths and thicknesses using time-resolved anisotropic magnetoresistance measurements. The Walker breakdown field, which separates translational and precessional DW propagation regimes, decreases for wider and thicker nanowires. On the contrary, the peak velocity at the Walker breakdown field is independent of the nanowire width and thickness. The Gilbert damping parameter α was measured independently and was found to be insensitive to nanowire width but decreased with increasing wire thickness. From these data the transverse anisotropy field and dynamical DW width could be determined.
Experimental demonstration of locally oxidized hybrid silicon-plasmonic waveguide
Authors: Goykhman Ilya , Desiatov Boris , Levy Uriel
Published: October 2010

We experimentally demonstrate a self-aligned approach for the fabrication of nanoscale hybrid silicon-plasmonic waveguide fabricated by local oxidation of silicon (LOCOS). Implementation of the LOCOS technique provides compatibility with standard complementary metal-oxide-semiconductor technology and allows avoiding lateral misalignment between the silicon waveguide and the upper metallic layer. We directly measured the propagation and the coupling loss of the fabricated hybrid waveguide using a near-field scanning optical microscope. The demonstrated structure provides nanoscale confinement of light together with a reasonable propagation length of ∼100 μm. As such, it is expected to become an important building block in future on-chip optoelectronic circuitry.
Supersaturation in nucleus and spiral growth of GaN in metal organic vapor phase epitaxy
Authors: Akasaka Tetsuya , Kobayashi Yasuyuki , Kasu Makoto
Published: October 2010

Nucleus and spiral growth mechanisms of GaN were experimentally studied by varying the degree of supersaturation, σ, in selective-area metal organic vapor phase epitaxy. The spiral growth rate of GaN increased proportionally to σ2 in the σ range from 0.0632 to 0.230. The nucleus growth rate of GaN was much smaller than the spiral one in the σ range. The nucleation rate was almost zero at σ lower than 0.130, suddenly increased at higher σ values, and reached ∼107 cm−2 s−1 at σ of 0.230. These results are consistent with a theoretical analysis [W. K. Burton, N. Cabrera, and F. C. Frank, Philos. Trans. R. Soc. London, Ser. A 243, 299 (1951)].
Monocliniclike local atomic structure in amorphous ZrO2 thin film
Authors: Cho Deok-Yong , Jung Hyung-Suk , Kim Jeong Hwan , Hwang Cheol Seong
Published: October 2010

The local atomic structure and electronic structure of amorphous ZrO2 (a-ZrO2) thin film were examined using the Zr K- and O K-edge x-ray absorption spectroscopy and x-ray photoelectron spectroscopy. It was found that a monoclinic local structure is stabilized in several nanometers-thick a-ZrO2 films due to the structural disorder. The distinct local structure in a-ZrO2 from the ordinary tetragonal ZrO2 (t-ZrO2) films results in different electronic structure with a decrease in the band gap by 0.5 eV. The reduced band gap and dielectric constant of a-ZrO2 suggest inferior gate leakage current performances compared to the t-ZrO2 films.
Excitation of short range surface plasmon polariton mode based on integrated hybrid coupler
Authors: Wan Ruiyuan , Liu Fang , Huang Yidong , Hu Shuai , Fan Boyu , Miura Yoshikatsu , Ohnishi Dai , Li Yunxiang , Li He , Xia Yang
Published: October 2010

The short range surface plasmon polariton (SRSPP) mode, which has an antisymmetric field profile on the two sides of a thin metal film, has been excited efficiently based on an integrated vertical hybrid coupler. The coupler is composed of an Au (SRSPP) waveguide and a SiNx (dielectric) waveguide. Highly efficient coupling between the SRSPP mode and conventional dielectric waveguide mode was demonstrated. A compact (less than 90 μm long) polarizer with a low TE insertion loss and high TM extinction ratio up to 30 dB was realized by utilizing different characteristics of the TE and TM modes in the hybrid coupler.
Destruction of α-synuclein based amyloid fibrils by a low temperature plasma jet
Authors: Karakas Erdinc , Munyanyi Agatha , Greene Lesley , Laroussi Mounir
Published: October 2010

Amyloid fibrils are ordered beta-sheet aggregates that are associated with a number of neurodegenerative diseases such as Alzheimer and Parkinson. At present, there is no cure for these progressive and debilitating diseases. Here we report initial studies that indicate that low temperature atmospheric pressure plasma can break amyloid fibrils into smaller units in vitro. The plasma was generated by the “plasma pencil,” a device capable of emitting a long, low temperature plasma plume/jet. This avenue of research may facilitate the development of a plasma-based medical treatment.
Thermally evaporated Cu2ZnSnS4 solar cells
Authors: Wang K. , Gunawan O. , Todorov T. , Shin B. , Chey S. J. , Bojarczuk N. A. , Mitzi D. , Guha S.
Published: October 2010

High efficiency Cu2ZnSnS4 solar cells have been fabricated on glass substrates by thermal evaporation of Cu, Zn, Sn, and S. Solar cells with up to 6.8% efficiency were obtained with absorber layer thicknesses less than 1 μm and annealing times in the minutes. Detailed electrical analysis of the devices indicate that the performance of the devices is limited by high series resistance, a “double diode” behavior of the current voltage characteristics, and an open circuit voltage that is limited by a carrier recombination process with an activation energy below the band gap of the material.
Alignment with the Horizontal Plane: Evidence for an Orientation Constraint in the Perception of Shape
Authors: Maniatis Lydia M
Published: October 2010

In order to convert a 2-D image to a 3-D percept, the visual system must apply constraints that maximize the chances that the result will be unique and veridical. Previously proposed constraints include one that maximizes the symmetry of the percept, and one that maximizes its compactness (Li et al, 2009 Vision Research49 979–991). Analysis of the 3-D percepts elicited by certain 2-D forms suggests the action of an additional constraint, favoring the alignment of the surfaces and/or axis of symmetry of the perceived object with the horizontal plane.
Characterization of mononuclear phagocytic cells in medaka fish transgenic for a
cxcr3a:gfp
reporter
Authors: Aghaallaei Narges , Bajoghli Baubak , Schwarz Heinz , Schorpp Michael , Boehm Thomas
Published: October 2010

Chemokines and chemokine receptors are key evolutionary innovations of vertebrates. They are involved in morphogenetic processes and play an important role in the immune system. Based on an analysis of the chemokine receptor gene family in teleost genomes, and the expression patterns of chemokine receptor genes during embryogenesis and the wounding response in young larvae of
Oryzias latipes
, we identified the chemokine receptor cxcr3a as a marker of innate immune cells. Cells expressing
cxcr3a
were characterized in fish transgenic for a
cxcr3a:gfp
reporter. In embryos and larvae,
cxcr3a
-expressing cells are motile in healthy and damaged tissues, and phagocytic; the majority of these cells has the morphology of tissue macrophages, whereas a small fraction has a dendritic phenotype. In adults,
cxcr3a
-positive cells continue to specifically express myeloid-associate markers and genes related to antigen uptake and presentation. By light microscopy and ultrastructural analysis, the majority of
cxcr3a
-expressing cells has a dendritic phenotype, whereas the remainder resembles macrophage-like cells. After challenge of adult fish with bacteria or CpG oligonucleotides, phagocytosing
cxcr3a
-positive cells in the blood up-regulated
il12p40
genes, compatible with their function as part of the mononuclear phagocytic system. Our results identify a marker of teleost mononuclear phagocytic cells and suggest a surprising degree of morphological and functional similarity between the innate immune systems of lower and higher vertebrates.
Network-level structural covariance in the developing brain
Authors: Zielinski Brandon A. , Gennatas Efstathios D. , Zhou Juan , Seeley William W.
Published: October 2010

Intrinsic or resting state functional connectivity MRI and structural covariance MRI have begun to reveal the adult human brain's multiple network architectures. How and when these networks emerge during development remains unclear, but understanding ontogeny could shed light on network function and dysfunction. In this study, we applied structural covariance MRI techniques to 300 children in four age categories (early childhood, 5–8 y; late childhood, 8.5–11 y; early adolescence, 12–14 y; late adolescence, 16–18 y) to characterize gray matter structural relationships between cortical nodes that make up large-scale functional networks. Network nodes identified from eight widely replicated functional intrinsic connectivity networks served as seed regions to map whole-brain structural covariance patterns in each age group. In general, structural covariance in the youngest age group was limited to seed and contralateral homologous regions. Networks derived using primary sensory and motor cortex seeds were already well-developed in early childhood but expanded in early adolescence before pruning to a more restricted topology resembling adult intrinsic connectivity network patterns. In contrast, language, social–emotional, and other cognitive networks were relatively undeveloped in younger age groups and showed increasingly distributed topology in older children. The so-called default-mode network provided a notable exception, following a developmental trajectory more similar to the primary sensorimotor systems. Relationships between functional maturation and structural covariance networks topology warrant future exploration.
Satellite-based global-ocean mass balance estimates of interannual variability and emerging trends in continental freshwater discharge
Authors: Syed Tajdarul H. , Famiglietti James S. , Chambers Don P. , Willis Josh K. , Hilburn Kyle
Published: October 2010

Freshwater discharge from the continents is a key component of Earth’s water cycle that sustains human life and ecosystem health. Surprisingly, owing to a number of socioeconomic and political obstacles, a comprehensive global river discharge observing system does not yet exist. Here we use 13 years (1994–2006) of satellite precipitation, evaporation, and sea level data in an ocean mass balance to estimate freshwater discharge into the global ocean. Results indicate that global freshwater discharge averaged 36,055 km
3
/y for the study period while exhibiting significant interannual variability driven primarily by El Niño Southern Oscillation cycles. The method described here can ultimately be used to estimate long-term global discharge trends as the records of sea level rise and ocean temperature lengthen. For the relatively short 13-year period studied here, global discharge increased by 540 km
3
/y
2
, which was largely attributed to an increase of global-ocean evaporation (768 km
3
/y
2
). Sustained growth of these flux rates into long-term trends would provide evidence for increasing intensity of the hydrologic cycle.
Genome-wide association study (GWAS)-identified disease risk alleles do not compromise human longevity
Authors: Beekman Marian , Nederstigt Christa , Suchiman H. Eka D. , Kremer Dennis , van der Breggen Ruud , Lakenberg Nico , Alemayehu Wendimagegn Ghidey , de Craen Anton J. M. , Westendorp Rudi G. J. , Boomsma Dorret I. , de Geus Eco J. C. , Houwing-Duistermaat Jeanine J. , Heijmans Bastiaan T. , Slagboom P. Eline
Published: October 2010

A set of currently known alleles increasing the risk for coronary artery disease, cancer, and type 2 diabetes as identified by genome-wide association studies was tested for compatibility with human longevity. Here, we show that nonagenarian siblings from long-lived families and singletons older than 85 y of age from the general population carry the same number of disease risk alleles as young controls. Longevity in this study population is not compromised by the cumulative effect of this set of risk alleles for common disease.
Genome-wide analysis reveals methyl-CpG–binding protein 2–dependent regulation of microRNAs in a mouse model of Rett syndrome
Authors: Wu Hao , Tao Jifang , Chen Pauline J. , Shahab Atif , Ge Weihong , Hart Ronald P. , Ruan Xiaoan , Ruan Yijun , Sun Yi E.
Published: October 2010

MicroRNAs (miRNAs) are a class of small, noncoding RNAs that function as posttranscriptional regulators of gene expression. Many miRNAs are expressed in the developing brain and regulate multiple aspects of neural development, including neurogenesis, dendritogenesis, and synapse formation. Rett syndrome (RTT) is a progressive neurodevelopmental disorder caused by mutations in the gene encoding
methyl-CpG–binding protein 2
(
MECP2
). Although Mecp2 is known to act as a global transcriptional regulator, miRNAs that are directly regulated by Mecp2 in the brain are not known. Using massively parallel sequencing methods, we have identified miRNAs whose expression is altered in cerebella of
Mecp2
-null mice before and after the onset of severe neurological symptoms. In vivo genome-wide analyses indicate that promoter regions of a significant fraction of dysregulated miRNA transcripts, including a large polycistronic cluster of brain-specific miRNAs, are DNA-methylated and are bound directly by Mecp2. Functional analysis demonstrates that the 3′ UTR of messenger RNA encoding
Brain-derived neurotrophic factor
(
Bdnf
) can be targeted by multiple miRNAs aberrantly up-regulated in the absence of Mecp2. Taken together, these results suggest that dysregulation of miRNAs may contribute to RTT pathoetiology and also may provide a valuable resource for further investigations of the role of miRNAs in RTT.
Decreased ENaC expression compensates the increased NCC activity following inactivation of the kidney-specific isoform of WNK1 and prevents hypertension
Authors: Hadchouel Juliette , Soukaseum Christelle , Büsst Cara , Zhou Xiao-ou , Baudrie Véronique , Zürrer Tany , Cambillau Michelle , Elghozi Jean-Luc , Lifton Richard P. , Loffing Johannes , Jeunemaitre Xavier
Published: October 2010

Mutations in
WNK1
and
WNK4
lead to familial hyperkalemic hypertension (FHHt). Because FHHt associates net positive Na
+
balance together with K
+
and H
+
renal retention, the identification of WNK1 and WNK4 led to a new paradigm to explain how aldosterone can promote either Na
+
reabsorption or K
+
secretion in a hypovolemic or hyperkalemic state, respectively.
WNK1
gives rise to L-WNK1, an ubiquitous kinase, and KS-WNK1, a kinase-defective isoform expressed in the distal convoluted tubule. By inactivating
KS-WNK1
in mice, we show here that this isoform is an important regulator of sodium transport.

KS-WNK1
−/−

mice display an increased activity of the Na-Cl cotransporter NCC, expressed specifically in the distal convoluted tubule, where it participates in the fine tuning of sodium reabsorption. Moreover, the expression of the ROMK and BKCa potassium channels was modified in

KS-WNK1
−/−

mice, indicating that KS-WNK1 is also a regulator of potassium transport in the distal nephron. Finally, we provide an alternative model for FHHt. Previous studies suggested that the activation of NCC plays a central role in the development of hypertension and hyperkalemia. Even though the increase in NCC activity in

KS-WNK1
−/−

mice was less pronounced than in mice overexpressing a mutant form of WNK4, our study suggests that the activation of Na–Cl cotransporter is not sufficient by itself to induce a hyperkalemic hypertension and that the deregulation of other channels, such as the Epithelial Na
+
channel (ENaC), is probably required.
NF-κB inhibits T-cell activation-induced, p73-dependent cell death by induction of MDM2
Authors: Busuttil Valere , Droin Nathalie , McCormick Laura , Bernassola Francesca , Candi Eleonora , Melino Gerry , Green Douglas R.
Published: October 2010

NF-κB is a key transcription factor involved in the regulation of T-cell activation and proliferation upon engagement of the T-cell receptor (TCR). T cells that lack the IκB kinase (IKKβ) are unable to activate NF-κB, and rapidly undergo apoptosis upon activation. NF-κB activation following T-cell receptor engagement induces the expression of Mdm2 through interaction with NF-κB sites in its P1 promoter, and enforced expression of Mdm2 protected T cells deficient for NF-κB activation from activation-induced cell death. In T cells with intact NF-κB signaling, ablation or pharmacologic inhibition of Mdm2 resulted in activation-induced apoptosis. Mdm2 coprecipitates with p73 in activated T cells, and apoptosis induced by inhibition of Mdm2 was p73-dependent. Further,
Bim
was identified as a p73 target gene required for cell death induced by Mdm2 inhibition, and a p73-responsive element in intron 1 of
Bim
was characterized. Our results demonstrate a pathway for survival of activated T cells through NF-κB–induced Mdm2, which blocks Bim-dependent apoptosis through binding and inhibition of p73.
Injectable hydrogel microbeads for fluorescence-based in vivo continuous glucose monitoring
Authors: Shibata Hideaki , Heo Yun Jung , Okitsu Teru , Matsunaga Yukiko , Kawanishi Tetsuro , Takeuchi Shoji
Published: October 2010

Fluorescent microbeads hold great promise for in vivo continuous glucose monitoring with wireless transdermal transmission and long-lasting activity. The full potential of fluorescent microbeads has yet to be realized due to insufficient intensity for transdermal transmission and material toxicity. This paper illustrates the highly-sensitive, biostable, long-lasting, and injectable fluorescent microbeads for in vivo continuous glucose monitoring. We synthesized a fluorescent monomer composed of glucose-recognition sites, a fluorogenic site, spacers, and polymerization sites. The spacers are designed to be long and hydrophilic for increasing opportunities to bind glucose molecules; consequently, the fluorescent monomers enable high-intensive responsiveness to glucose. We then fabricated injectable-sized fluorescent polyacrylamide hydrogel beads with high uniformity and high throughput. We found that our fluorescent beads provide sufficient intensity to transdermally monitor glucose concentrations in vivo. The fluorescence intensity successfully traced the blood glucose concentration fluctuation, indicating our method has potential uses in highly-sensitive and minimally invasive continuous blood glucose monitoring.
SNARE tagging allows stepwise assembly of a multimodular medicinal toxin
Authors: Darios Frédéric , Niranjan Dhevahi , Ferrari Enrico , Zhang Fan , Soloviev Mikhail , Rummel Andreas , Bigalke Hans , Suckling Jason , Ushkaryov Yuri , Naumenko Nikolay , Shakirzyanova Anastasia , Giniatullin Rashid , Maywood Elizabeth , Hastings Michael , Binz Thomas , Davletov Bazbek
Published: October 2010

Generation of supramolecular architectures through controlled linking of suitable building blocks can offer new perspectives to medicine and applied technologies. Current linking strategies often rely on chemical methods that have limitations and cannot take full advantage of the recombinant technologies. Here we used SNARE proteins, namely, syntaxin, SNAP25, and synaptobrevin, which form stable tetrahelical complexes that drive fusion of intracellular membranes, as versatile tags for irreversible linking of recombinant and synthetic functional units. We show that SNARE tagging allows stepwise production of a functional modular medicinal toxin, namely, botulinum neurotoxin type A, commonly known as BOTOX. This toxin consists of three structurally independent units: Receptor-binding domain (Rbd), Translocation domain (Td), and the Light chain (Lc), the last being a proteolytic enzyme. Fusing the receptor-binding domain with synaptobrevin SNARE motif allowed delivery of the active part of botulinum neurotoxin (Lc-Td), tagged with SNAP25, into neurons. Our data show that SNARE-tagged toxin was able to cleave its intraneuronal molecular target and to inhibit release of neurotransmitters. The reassembled toxin provides a safer alternative to existing botulinum neurotoxin and may offer wider use of this popular research and medical tool. Finally, SNARE tagging allowed the Rbd portion of the toxin to be used to deliver quantum dots and other fluorescent markers into neurons, showing versatility of this unique tagging and self-assembly technique. Together, these results demonstrate that the SNARE tetrahelical coiled-coil allows controlled linking of various building blocks into multifunctional assemblies.
An atypical member of the light-harvesting complex stress-related protein family modulates diatom responses to light
Authors: Bailleul Benjamin , Rogato Alessandra , de Martino Alessandra , Coesel Sacha , Cardol Pierre , Bowler Chris , Falciatore Angela , Finazzi Giovanni
Published: October 2010

Diatoms are prominent phytoplanktonic organisms that contribute around 40% of carbon assimilation in the oceans. They grow and perform optimally in variable environments, being able to cope with unpredictable changes in the amount and quality of light. The molecular mechanisms regulating diatom light responses are, however, still obscure. Using knockdown
Phaeodactylum tricornutum
transgenic lines, we reveal the key function of a member of the light-harvesting complex stress-related (LHCSR) protein family, denoted LHCX1, in modulation of excess light energy dissipation. In contrast to green algae, this gene is already maximally expressed in nonstressful light conditions and encodes a protein required for efficient light responses and growth. LHCX1 also influences natural variability in photoresponse, as evidenced in ecotypes isolated from different latitudes that display different LHCX1 protein levels. We conclude, therefore, that this gene plays a pivotal role in managing light responses in diatoms.
GAPDH regulates cellular heme insertion into inducible nitric oxide synthase
Authors: Chakravarti Ritu , Aulak Kulwant S. , Fox Paul L. , Stuehr Dennis J.
Published: October 2010

Heme proteins play essential roles in biology, but little is known about heme transport inside mammalian cells or how heme is inserted into soluble proteins. We recently found that nitric oxide (NO) blocks cells from inserting heme into several proteins, including cytochrome P450s, hemoglobin, NO synthases, and catalase. This finding led us to explore the basis for NO inhibition and to identify cytosolic proteins that may be involved, using inducible NO synthase (iNOS) as a model target. Surprisingly, we found that GAPDH plays a key role. GAPDH was associated with iNOS in cells. Pure GAPDH bound tightly to heme or to iNOS in an NO-sensitive manner. GAPDH knockdown inhibited heme insertion into iNOS and a GAPDH mutant with defective heme binding acted as a dominant negative inhibitor of iNOS heme insertion. Exposing cells to NO either from a chemical donor or by iNOS induction caused GAPDH to becomeS-nitrosylated at Cys152. Expressing a GAPDH C152S mutant in cells or providing a drug to selectively block GAPDHS-nitrosylation both made heme insertion into iNOS resistant to the NO inhibition. We propose that GAPDH delivers heme to iNOS through a process that is regulated by itsS-nitrosylation. Our findings may uncover a fundamental step in intracellular heme trafficking, and reveal a mechanism whereby NO can govern the process.
Asian dust particles converted into aqueous droplets under remote marine atmospheric conditions
Authors: Tobo Yutaka , Zhang Daizhou , Matsuki Atsushi , Iwasaka Yasunobu
Published: October 2010

The chemical history of dust particles in the atmosphere is crucial for assessing their impact on both the Earth’s climate and ecosystem. So far, a number of studies have shown that, in the vicinity of strong anthropogenic emission sources, Ca-rich dust particles can be converted into aqueous droplets mainly by the reaction with gaseous HNO
3
to form Ca(NO
3
)
2
. Here we show that other similar processes have the potential to be activated under typical remote marine atmospheric conditions. Based on field measurements at several sites in East Asia and thermodynamic predictions, we examined the possibility for the formation of two highly soluble calcium salts, Ca(NO
3
)
2
and CaCl
2
, which can deliquesce at low relative humidity. According to the results, the conversion of insoluble CaCO
3
to Ca(NO
3
)
2
tends to be dominated over urban and industrialized areas of the Asian continent, where the concentrations of HNO
3
exceed those of HCl ([HNO
3
/HCl] >  ∼ 1). In this regime, CaCl
2
is hardly detected from dust particles. However, the generation of CaCl
2
becomes detectable around the Japan Islands, where the concentrations of HCl are much higher than those of HNO
3
([HNO
3
/HCl] <  ∼ 0.3). We suggest that elevated concentrations of HCl in the remote marine boundary layer are sufficient to modify Ca-rich particles in dust storms and can play a more important role in forming a deliquescent layer on the particle surfaces as they are transported toward remote ocean regions.
Development of the malaria parasite in the skin of the mammalian host
Authors: Gueirard Pascale , Tavares Joana , Thiberge Sabine , Bernex Florence , Ishino Tomoko , Milon Genevieve , Franke–Fayard Blandine , Janse Chris J. , Ménard Robert , Amino Rogerio
Published: October 2010

The first step of
Plasmodium
development in vertebrates is the transformation of the sporozoite, the parasite stage injected by the mosquito in the skin, into merozoites, the stage that invades erythrocytes and initiates the disease. The current view is that, in mammals, this stage conversion occurs only inside hepatocytes. Here, we document the transformation of sporozoites of rodent-infecting
Plasmodium
into merozoites in the skin of mice. After mosquito bite, ∼50% of the parasites remain in the skin, and at 24 h ∼10% are developing in the epidermis and the dermis, as well as in the immunoprivileged hair follicles where they can survive for weeks. The parasite developmental pathway in skin cells, although frequently abortive, leads to the generation of merozoites that are infective to erythrocytes and are released via merosomes, as typically observed in the liver. Therefore, during malaria in rodents, the skin is not just the route to the liver but is also the final destination for many inoculated parasites, where they can differentiate into merozoites and possibly persist.
Controlling the growth and shape of chiral supramolecular polymers in water
Authors: Besenius Pol , Portale Giuseppe , Bomans Paul H. H. , Janssen Henk M. , Palmans Anja R. A. , Meijer E. W.
Published: October 2010

A challenging target in the noncovalent synthesis of nanostructured functional materials is the formation of uniform features that exhibit well-defined properties, e.g., precise control over the aggregate shape, size, and stability. In particular, for aqueous-based one-dimensional supramolecular polymers, this is a daunting task. Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing out attractive noncovalent forces within the hydrophobic core of the polymerizing building blocks with electrostatic repulsive interactions on the hydrophilic rim we managed to switch from elongated, rod-like assemblies to small and discrete objects. Intriguingly this rod-to-sphere transition is expressed in a loss of cooperativity in the temperature-dependent self-assembly mechanism. The aggregates were characterized using circular dichroism, UV and 1H-NMR spectroscopy, small angle X-ray scattering, and cryotransmission electron microscopy. In analogy to many systems found in biology, mechanistic details of the self-assembly pathways emphasize the importance of cooperativity as a key feature that dictates the physical properties of the produced supramolecular polymers.
NADPH oxidase-4 mediates protection against chronic load-induced stress in mouse hearts by enhancing angiogenesis
Authors: Zhang Min , Brewer Alison C. , Schröder Katrin , Santos Celio X. C. , Grieve David J. , Wang Minshu , Anilkumar Narayana , Yu Bin , Dong Xuebin , Walker Simon J. , Brandes Ralf P. , Shah Ajay M.
Published: October 2010

Cardiac failure occurs when the heart fails to adapt to chronic stresses. Reactive oxygen species (ROS)-dependent signaling is implicated in cardiac stress responses, but the role of different ROS sources remains unclear. Here we report that NADPH oxidase-4 (Nox4) facilitates cardiac adaptation to chronic stress. Unlike other Nox proteins, Nox4 activity is regulated mainly by its expression level, which increases in cardiomyocytes under stresses such as pressure overload or hypoxia. To investigate the functional role of Nox4 during the cardiac response to stress, we generated mice with a genetic deletion of Nox4 or a cardiomyocyte-targeted overexpression of Nox4. Basal cardiac function was normal in both models, but
Nox4
-null animals developed exaggerated contractile dysfunction, hypertrophy, and cardiac dilatation during exposure to chronic overload whereas
Nox4
-transgenic mice were protected. Investigation of mechanisms underlying this protective effect revealed a significant Nox4-dependent preservation of myocardial capillary density after pressure overload. Nox4 enhanced stress-induced activation of cardiomyocyte hypoxia inducible factor 1 and the release of vascular endothelial growth factor, resulting in increased paracrine angiogenic activity. These data indicate that cardiomyocyte Nox4 is a unique inducible regulator of myocardial angiogenesis, a key determinant of cardiac adaptation to overload stress. Our results also have wider relevance to the use of nonspecific antioxidant approaches in cardiac disease and may provide an explanation for the failure of such strategies in many settings.
Bacterial Na
+
-translocating ferredoxin:NAD
+
oxidoreductase
Authors: Biegel Eva , Müller Volker
Published: October 2010

The anaerobic acetogenic bacterium
Acetobacterium woodii
carries out a unique type of Na
+
-motive, anaerobic respiration with caffeate as electron acceptor, termed “caffeate respiration.” Central, and so far the only identified membrane-bound reaction in this respiration pathway, is a ferredoxin:NAD
+
oxidoreductase (Fno) activity. Here we show that inverted membrane vesicles of
A. woodii
couple electron transfer from reduced ferredoxin to NAD
+
with the transport of Na
+
from the outside into the lumen of the vesicles. Na
+
transport was electrogenic, and accumulation was inhibited by sodium ionophores but not protonophores, demonstrating a direct coupling of Fno activity to Na
+
transport. Results from inhibitor studies are consistent with the hypothesis that Fno activity coupled to Na
+
translocation is catalyzed by the Rnf complex, a membrane-bound, iron–sulfur and flavin-containing electron transport complex encoded by many bacterial and some archaeal genomes. Fno is a unique type of primary Na
+
pump and represents an early evolutionary mechanism of energy conservation that expands the redox range known to support life. In addition, it explains the lifestyle of many anaerobic bacteria and gives a mechanistic explanation for the enigma of the energetic driving force for the endergonic reduction of ferredoxin with NADH plus H
+
as reductant in a number of aerobic bacteria.
Dopamine modulates synaptic plasticity in dendrites of rat and human dentate granule cells
Authors: Hamilton Trevor J. , Wheatley B. Matthew , Sinclair D. Barry , Bachmann Madeline , Larkum Matthew E. , Colmers William F.
Published: October 2010

The mechanisms underlying memory formation in the hippocampal network remain a major unanswered aspect of neuroscience. Although high-frequency activity appears essential for plasticity, salience for memory formation is also provided by activity in ventral tegmental area (VTA) dopamine projections. Here, we report that activation of dopamine D1 receptors in dentate granule cells (DGCs) can preferentially increase dendritic excitability to both high-frequency afferent activity and high-frequency trains of backpropagating action potentials. Using whole-cell patch clamp recordings, calcium imaging, and neuropeptide Y to inhibit postsynaptic calcium influx, we found that activation of dendritic voltage-dependent calcium channels (VDCCs) is essential for dopamine-induced long-term potentiation (LTP), both in rat and human dentate gyrus (DG). Moreover, we demonstrate previously unreported spike-timing–dependent plasticity in the human hippocampus. These results suggest that when dopamine is released in the dentate gyrus with concurrent high-frequency activity there is an increased probability that synapses will be strengthened and reward-associated spatial memories will be formed.
Both sides retaliate in the Israeli–Palestinian conflict
Authors: Haushofer Johannes , Biletzki Anat , Kanwisher Nancy
Published: October 2010

Ending violent international conflicts requires understanding the causal factors that perpetuate them. In the Israeli–Palestinian conflict, Israelis and Palestinians each tend to see themselves as victims, engaging in violence only in response to attacks initiated by a fundamentally and implacably violent foe bent on their destruction. Econometric techniques allow us to empirically test the degree to which violence on each side occurs in response to aggression by the other side. Prior studies using these methods have argued that Israel reacts strongly to attacks by Palestinians, whereas Palestinian violence is random (i.e., not predicted by prior Israeli attacks). Here we replicate prior findings that Israeli killings of Palestinians increase after Palestinian killings of Israelis, but crucially show further that when nonlethal forms of violence are considered, and when a larger dataset is used, Palestinian violence also reveals a pattern of retaliation: (
i
) the firing of Palestinian rockets increases sharply after Israelis kill Palestinians, and (
ii
) the probability (although not the number) of killings of Israelis by Palestinians increases after killings of Palestinians by Israel. These findings suggest that Israeli military actions against Palestinians lead to escalation rather than incapacitation. Further, they refute the view that Palestinians are uncontingently violent, showing instead that a significant proportion of Palestinian violence occurs in response to Israeli behavior. Well-established cognitive biases may lead participants on each side of the conflict to underappreciate the degree to which the other side's violence is retaliatory, and hence to systematically underestimate their own role in perpetuating the conflict.
DNA conformational changes at the primer-template junction regulate the fidelity of replication by DNA polymerase
Authors: Datta Kausiki , Johnson Neil P. , von Hippel Peter H.
Published: October 2010

Local conformational changes in primer-template (P/T) DNA are involved in the selective incorporation of dNTP by DNA polymerases (DNAP). Here we use near UV CD and fluorescence spectra of pairs of base analogue probes, substituted either at the primer terminus or in the coding region of the template strand, to monitor and interpret conformational changes at and near the coding base of the template in P/T DNA complexes with Klenow fragment (KF) DNAP as the polymerase moves through the nucleotide addition cycle. Incoming dNTPs and rNTPs encounter binary complexes in which the 3′-end of the primer shuttles between the polymerization (
pol
) and exonuclease (
exo
) sites of DNAPs, even for perfectly complementary P/T DNA sequences. We have used spectral changes of probes inserted in both strands to monitor this two-state distribution and determine how it depends on the formation of ternary complexes with both complementary (“correct”) and noncomplementary (“incorrect”) NTPs and on the local sequence of the P/T DNA. The results show that the relative occupancy of the
exo
and
pol
sites is coupled to conformational changes in the P/T DNA of the complex that are partially regulated by the incoming NTP. We find that the coding base on the template strand is unperturbed by the binding of incorrect dNTPs, while binding of complementary rNTPs induces a novel template conformation. We conclude that, in addition to its editing function, primer strand occupancy of the 3′-
exo
site may also serve as a regulatory checkpoint for accurate dNTP selection in DNA synthesis.
An h-Type Thioredoxin Functions in Tobacco Defense Responses to Two Species of Viruses and an Abiotic Oxidative Stress
Authors: Sun Lijun , Ren Haiying , Liu Ruoxue , Li Baoyan , Wu Tingquan , Sun Feng , Liu Huimin , Wang Xiaomeng , Dong Hansong
Published: October 2010

Various thioredoxin (Trx) proteins have been identified in plants. However, many of the physiological roles played by these proteins remain to be elucidated. We cloned a TRXh-like gene predicted to encode an h-type Trx in tobacco (Nicotiana tabacum) and designated it NtTRXh3, based on the biochemical activity of the NtTRXh3 protein. Overexpression of NtTRXh3 conferred resistance to Tobacco mosaic virus and Cucumber mosaic virus, both of which showed reduced multiplication and pathogenicity in NtTRXh3-overexpressing plants compared with controls. NtTRXh3 overexpression also enhanced tobacco resistance to oxidative stress induced by paraquat, an herbicide that inhibits the production of reducing equivalents by chloroplasts. The NtTRXh3 protein localized exclusively to chloroplasts in coordination with the maintenance of cellular reducing conditions, which accompanied an elevation in the glutathione/glutathione disulfide couple ratio. NtTRXh3 gene expression and NtTRXh3 protein production were necessary for these defensive responses, because they were all arrested when NtTRXh3 was silenced and the production of NtTRXh3 protein was abrogated. These results suggest that NtTRXh3 is involved in the resistance of tobacco to virus infection and abiotic oxidative stress.
BAK1 Is Not a Target of the Pseudomonas syringae Effector AvrPto
Authors: Xiang Tingting , Zong Na , Zhang Jie , Chen Jinfeng , Chen Mingsheng , Zhou Jian-Min
Published: October 2010

Plant cell surface-localized receptor kinases such as FLS2, EFR, and CERK1 play a crucial role in detecting invading pathogenic bacteria. Upon stimulation by bacterium-derived ligands, FLS2 and EFR interact with BAK1, a receptor-like kinase, to activate immune responses. A number of Pseudomonas syringae effector proteins are known to block immune responses mediated by these receptors. Previous reports suggested that both FLS2 and BAK1 could be targeted by the P. syringae effector AvrPto to inhibit plant defenses. Here, we provide new evidence further supporting that FLS2 but not BAK1 is targeted by AvrPto in plants. The AvrPto-FLS2 interaction prevented the phosphorylation of BIK1, a downstream component of the FLS2 pathway.
Enhanced Glutathione Metabolism Is Correlated with Sulfur-Induced Resistance in Tobacco mosaic virus–Infected Genetically Susceptible Nicotiana tabacum Plants
Authors: Höller Kerstin , Király Lóránt , Künstler András , Müller Maria , Gullner Gábor , Fattinger Maria , Zechmann Bernd
Published: October 2010

Sulfur-induced resistance, also known as sulfur-enhanced defense (SIR/SED) was investigated in Nicotiana tabacum cv. Samsun nn during compatible interaction with Tobacco mosaic virus (TMV) in correlation with glutathione metabolism. To evaluate the influence of sulfur nutritional status on virus infection, tobacco plants were treated with nutrient solutions containing either sufficient sulfate (+S) or no sulfate (−S). Sufficient sulfate supply resulted in a suppressed and delayed symptom development and diminished virus accumulation over a period of 14 days after inoculation as compared with −S conditions. Expression of the defense marker gene PR-1a was markedly upregulated in sulfate-treated plants during the first day after TMV inoculation. The occurrence of SIR/SED correlated with a higher level of activity of sulfate assimilation, cysteine, and glutathione metabolism in plants treated with sulfate. Additionally, two key genes involved in cysteine and glutathione biosynthesis (encoding adenosine 5′-phosphosulfate reductase and γ-glutamylcysteine synthetase, respectively) were upregulated within the first day after TMV inoculation under +S conditions. Sulfate withdrawal from the soil was accelerated at the beginning of the infection, whereas it declined in the long term, leading to an accumulation of sulfur in the soil of plants grown with sulfate. This observation could be correlated with a decrease in sulfur contents in TMV-infected leaves in the long term. In summary, this is the first study that demonstrates a link between the activation of cysteine and glutathione metabolism and the induction of SIR/SED during a compatible plant-virus interaction in tobacco plants, indicating a general mechanism behind SIR/SED.
Effects of Amino-Acid Substitutions in the Brome mosaic virus Capsid Protein on RNA Encapsidation
Authors: Hema Masarapu , Murali Ayaluru , Ni Peng , Vaughan Robert C. , Fujisaki Koki , Tsvetkova Irina , Dragnea Bogdan , Kao C. Cheng
Published: October 2010

Brome mosaic virus (BMV) packages its genomic RNAs (RNA1, RNA2, and RNA3) and subgenomic RNA4 into three different particles. However, since the RNAs in the virions have distinct lengths and electrostatic charges, we hypothesize that subsets of the virions should have distinct properties. A glutamine to cysteine substitution at position 120 of the capsid protein (CP) was found to result in a mutant virus named QC that exhibited a dramatically altered ratio of the RNAs in virions. RNA2 was far more abundant than the other RNAs, although the ratios could be affected by the host plant species. RNAs with the QC mutation were competent for replication early in the infection, suggesting that they were either selectively packaged or degraded after packaging. In support of the latter idea, low concentrations of truncated RNA1 that co-migrated with RNA2 were found in the QC virions. Spectroscopic analysis and peptide fingerprinting experiments showed that the QC virus capsid interacted with the encapsidated RNAs differently than did the wild type. Furthermore, wild-type BMV RNA1 was found to be more susceptible to nuclease digestion relative to RNA2 as a function of the buffer pH. Other BMV capsid mutants also had altered ratios of packaged RNAs.
Maternal country of origin, breast milk characteristics and potential influences on immunity in offspring
Authors: Holmlund U , Amoudruz P , Johansson M A , Haileselassie Y , Ongoiba A , Kayentao K , Traoré B , Doumbo S , Schollin J , Doumbo O , Montgomery S M , Sverremark-Ekström E
Published: October 2010

Breast milk contains pro- and anti-inflammatory cytokines and chemokines with potential to influence immunological maturation in the child. We have shown previously that country of birth is associated with the cytokine/chemokine profile of breast milk. In this study we have investigated how these differences in breast milk affect the cellular response of cord blood mononuclear cells (CBMCs) and intestinal epithelial cells (IECs, cell line HT-29) to microbial challenge. Ninety-five women were included: 30 from Mali in West Africa, 32 Swedish immigrants and 33 native Swedish women. CBMCs or IECs were stimulated in vitro with breast milk, alone or in combination with lipopolysaccharide (LPS) or peptidoglycan (PGN). Breast milk in general abrogated the LPS-induced down-regulation of surface CD14 and Toll-like receptor (TLR)-4 expression on CB monocytes, while inhibiting the PGN-induced TLR-2 up-regulation. However, breast milk from immigrant women together with LPS induced a lower CBMC release of interleukin (IL)-6 (P = 0·034) and CXCL-8/IL-8 (P = 0·037) compared with breast milk from Swedish women, while breast milk from Swedish women and Mali women tended to increase the response. The same pattern of CXCL-8/IL-8 release could be seen after stimulation of IECs (HT-29). The lower CBMC and IEC (HT-29) responses to microbial compounds by breast milk from immigrant women could be explained by the fact that breast milk from the immigrant group showed a divergent pro- and anti-inflammatory content for CXCL-8/IL-8, transforming growth factor-β1 and soluble CD14, compared to the other two groups of women. This may have implications for maturation of their children's immune responses.
Low‐intensity agriculture increases farmland bird abundances in France
Authors: Doxa Aggeliki , Bas Yves , Paracchini Maria Luisa , Pointereau Philippe , Terres Jean‐Michel , Jiguet Frédéric
Published: October 2010

1. Farmland biodiversity continues to decline mainly because of agricultural intensification and land abandonment. Agri‐environment schemes can be designed to halt this loss by favouring extensification of agricultural practices and through sympathetic management of field boundaries and fallow land. In Europe, High Nature Value (HNV) farmland is defined as low‐intensity farmland supporting or associated with a high rate of biodiversity, in terms of species richness or habitat diversity and therefore plays a crucial role in the maintenance of European biodiversity. However, no large‐scale analysis has explored the role of these areas in achieving conservation goals.

2. We analysed information from widely used indicators in order to describe the impact of low‐intensity agriculture on farmland biodiversity in France. We used the HNV farmland indicator, based on agricultural statistics such as the Farm Structure Survey and the grassland survey, and common bird indicators, i.e. the Farmland Bird Indicator (FBI), the Community Specialization Index (CSI) and species richness indexes, based on the French Breeding Bird Survey.

3. Temporal trends in the farmland bird indicator showed that populations of farmland birds were more likely to increase inside HNV areas compared to non‐HNV areas. Although species richness is not higher within HNV farmland, bird communities are composed by more specialist species than in non‐HNV areas. In addition, these specialist bird species are significantly more abundant in HNV areas.

4. Synthesis and applications. Further farmland biodiversity decline is potentially reversible through an appropriate management of HNV areas. Existing and future agri‐environment schemes should focus on preserving and extending HNV farmland, by favouring the maintenance of low‐intensity agriculture and landscape complexity. Priority should be given to preserving diversity at the community level, with the help of adequate indicators, such as the ones presented here. The role of HNV farmland or similar concepts in combining agriculture and biodiversity goals should be further analysed and further used as large‐scale conservation tools.