bluuebunny/crossref_metadata_2025 huggingface dataset:
JASMINE – design and method of data reduction
Authors: Yamada Yoshiyuki , Gouda Naoteru , Yano Taihei , Kobayashi Yukiyasu , Niwa Yoshito ,   JASMINE Working Group
Published: July 2008

Japan Astrometry Satellite Mission for Infrared Exploration (JASMINE) aims to construct a map of the Galactic bulge with 10 μ arc sec accuracy. We use z-band CCD for avoiding dust absorption, and observe about 10 × 20 degrees area around the Galactic bulge region. Because the stellar density is very high, each FOVs can be combined with high accuracy. With 5 years observation, we will construct 10 μ arc sec accurate map.

In this poster, I will show the observation strategy, design of JASMINE hardware, reduction scheme, and error budget. We also construct simulation software named JASMINE Simulator. We also show the simulation results and design of software.
Galaxy bulges at mid- and high-redshift
Authors: Conselice Christopher J.
Published: July 2008

Bulges are a major galaxy component in the nearby universe, and are one of the primary features that differentiates and defines galaxies. The origin of bulges can be directly probed in part by examining distant galaxies to search for high redshift bulges, and to study the properties of bulges in formation. We review the evidence for bulges at high redshift in this article, and how by studying bulges through a variety of approaches, including through morphological, colour, and stellar mass selection, we can determine when and how these systems assembled. We argue that the majority of the most massive ‘classical’ bulges are in place byz~ 1.5 − 2, and likely formed very early through major mergers. Other, likely lower mass, bulges form through a secular process along with their disks. Direct observations suggest that these two formation processes are occurring, as spheroids are commonly seen atz< 1, as are disks and spiral galaxies in the form of luminous diffuse objects, clump-clusters, and chain galaxies. However, bulge+disk systems are relatively rare untilz~ 1, suggesting that this structural assembly occurred relatively late.
The fundamental plane of bulges at intermediate redshift
Authors: MacArthur Lauren A. , Ellis Richard S. , Treu Tommaso
Published: July 2008

We report on a new study aimed at understanding the diversity and evolutionary properties of distant galactic bulges in the context of well-established trends for pure spheroidal galaxies. Bulges have been isolated for a sample of 137 spiral galaxies in the GOODS fields within the redshift range 0.1 < z < 1.2. Using proven photometric techniques we determine for each galaxy the characteristic parameters (size, surface brightness, profile shape) in the 4 GOODS-ACS imaging bands of both the disk and bulge components. Using the DEIMOS spectrograph on Keck, precision stellar velocity dispersions were secured for a sizeable fraction of the bulges. This has enabled us to compare the Fundamental Plane of our distant bulges with that of field spheroidal galaxies in a similar redshift range. Bulges in spiral galaxies with a bulge-to-total luminosity ratio (B/T) > 0.2 show very similar patterns of evolution to those seen for low luminosity spheroidals. To first order, their recent mass assembly histories are equivalent.
Keck laser guide star observations of 11 GOODS-South Chandra sources at z ~ 1
Authors: Ammons S. Mark , Melbourne Jason , Koo David C. , Max Claire E.
Published: July 2008

The Center for Adaptive Optics (CfAO) Treasury Survey (CATS) has observed 11 Chandra sources (10 AGN) at z ~ 1 in the GOODS-South field with the laser guide star adaptive optics (LGSAO) system at Keck Observatory. We combine this K band imaging with ACS imaging in the B, V, I, and z bands to obtain multi-color imaging at a spatial resolution better than 100 mas in all bands. We attempt to remove central optical point sources from AGN using the GALFIT (Peng et al. 2002) routine. We fit Bruzual & Charlot (2003) tau-models to the residuals and find young, dusty stellar populations in the central 1-2 kpc (the mean central optical depth at rest-frame 500 nm is 4-5).
Mass and kinematics of late-type galaxies (1.3 < z < 3.3) from the VVDS
Authors: Lemoine-Busserolle M. , Contini T. , Le Fèvre O. , Kissler-Patig M. ,   the VVDS Consortium
Published: July 2008

Galaxy kinematics at early epochs give a key insight into the assembly of mass. Redshifts z ~ 1 − 3 appear to be the peak of the star formation rate of the Universe, possibly corresponding to the maximal merger activity. 2D velocity fields of late-type galaxies can be used to put important constraints on its total mass and hence on its dark matter halo. As dark halos are thought to govern the rate of galaxy evolution, securing reliable mass measurements for early systems at high redshift is a fundamental observational goal. In addition, accurate inner shape rotation curves, only drawed by 3D spectroscopic studies, should allow to disentangle cosmological scenarii. In the purpose of probing the evolution in masses and mass-to-light ratios of the galaxies during an epoch of expected strong evolution, and setting constrains on their formation and evolution, we present preliminary results obtained from Integral Field NIR Spectroscopy with SINFONI/VLT of a first sample of ten high-z (1.3 < z < 3.3) late-type galaxies selected in the VIMOS/VLT Deep Survey (VVDS). The SINFONI NIR-IFU mode allow to spatially resolve galaxy dynamics using bright rest-frame optical emission lines, in order to perform statistical studies of dynamical masses at this early epochs.
Towards a robust estimate of the merger rate evolution using near-IR photometry
Authors: Rawat Abhishek , Hammer Francois , Kembhavi Ajit K , Flores Hector
Published: July 2008

We use a combination of deep, high angular resolution imaging data from the HST/ACS GOODS survey and ground based near-IR Ks images to derive the evolution of the galaxy major merger rate in the redshift range 0.2 ≤ z ≤ 1.2. We select galaxies on the sole basis of their J-band rest-frame, absolute magnitude, which is a good tracer of the stellar mass. We find steep evolution with redshift, with the merger rate ∝ (1+z)2.44±0.39 for optically selected pairs, and ∝ (1+z)2.07±0.74 for pairs selected in the near-IR. Our result is unlikely affected by luminosity evolution which is relatively modest when using a rest-frame J band selection. The major merger rate evolves by a factor ~5 from the current epoch to 1.6×10−3 Mpc−3 Gyr−1 at z ~ 1.2, suggesting that 58%×(0.5 Gyr/τ) of all galaxies with MJ ≤ −19.5 have undergone a major merger in the last ~ 8 Gyr (where τ is the merger timescale). Interestingly, we find no effect on the derived major merger rate due to the presence of the large scale structure at z = 0.735 in the CDFS. We do find some evidence for increased star formation due to possible interactions between members of a pair using Spitzer MIPS 24μm fluxes to estimate the SFR.
Isotopic fractionation by diffusion in groundwater
Authors: LaBolle Eric M. , Fogg Graham E. , Eweis Juana B. , Gravner Janko , Leaist Derek G.
Published: July 2008

During the last decade, isotopic fractionation has gained acceptance as an indicator of microbiological and chemical transformations of contaminants in groundwater. These transformation processes typically favor isotopically light, compared to isotopically heavy, contaminants, resulting in enrichment of the latter in the residual aqueous phase. In these isotope applications, it has been generally presumed that physical transport processes in groundwater have a negligible effect on isotopic enrichment. It is well known, however, that aqueous phase diffusion generally proceeds faster for isotopically light, compared to isotopically heavy, solute molecules, often resulting in isotopic fractionation in groundwater. This paper considers the potential for isotopic fractionation during transport in groundwater resulting from minute isotopic effects on aqueous diffusion coefficients. Analyses of transport in heterogeneous systems delimit the viable range of isotopic fractionation by diffusion in groundwater. Results show that diffusion can result in similar degrees of depletion and enrichment of isotopically heavy solutes during transport in heterogeneous systems with significant diffusion rate–limited mass transfer between fast‐ and slow‐flow zones. Additional analyses and examples explore conditions that attenuate the development of significant fractionation. Examples are presented for 13C methyl tertiary butyl ether and deuterated and nondeuterated isopropanol and tertiary butyl alcohol using aqueous diffusion coefficients measured by the Taylor dispersion method with refractive index profiling as a part of this study. Examples elucidate the potential for diffusive fractionation as a confounder in isotope applications and emphasize the importance of hydrogeologic analysis for assessing the role of diffusive fractionation in isotope applications at contaminant field sites.
Oceanic Kelvin waves and tropical Atlantic intraseasonal variability: 1. Kelvin wave characterization
Authors: Polo Irene , Lazar Alban , Rodriguez‐Fonseca Belen , Arnault Sabine
Published: July 2008

Oceanic Kelvin waves from the equator to the West African coast are investigated in the framework of tropical Atlantic intraseasonal variability. In order to better highlight the wave propagations, a 25–95 day band‐pass filter was applied to the sea surface height (SSH) product derived from the TOPEX/POSEIDON altimeter and an ocean general circulation model simulation for the 1993–2000 period. In addition to equatorial eastward propagations, our analysis reveals recurrent and continuous propagations distinguishable over thousands of kilometers poleward along the coasts as far as about 10°–15° latitude, a novel result with altimeter data. The variance of the filtered SSH signal goes from 1 cm at the equator to 2 cm at the African coast. Estimates of the phase speed range from 1.5 to 2.1 m/s along the equator and the West African coastline. Such values are very close to those of equatorial Kelvin wave propagations, likely dominated by the first two baroclinic modes, supporting the fact that the coastal propagations are coastally trapped Kelvin waves. In order to simplify the description of these Kelvin waves, we present an intraseasonal climatology which reveals regular boreal autumn–winter equator to coast propagations. An improved description is achieved thanks to the computation of an extended empirical orthogonal function for the boreal autumn–winter propagations. Lag correlation of SSH signals allows for a twofold quantification: the phase speed and the importance of remote forcing along the coast. The remote forcing effect of intraseasonal Kelvin waves is clearly evidenced over coastal upwelling regions as far as 10°–15° latitude. The physical mechanism associated with the forcing of the Kelvin waves and its impacts will be investigated in a future paper.
In‐flight comparison of Brewer‐Mast and electrochemical concentration cell ozonesondes
Authors: Stübi René , Levrat Gilbert , Hoegger Bruno , Viatte Pierre , Staehelin Johannes , Schmidlin F. J.
Published: July 2008

The analysis of 140 dual flights between two types of ozonesondes, namely, the Brewer‐Mast (BM) and the electrochemical concentration cell (ECC), is presented in this study. These dual flights were performed before the transition from BM to ECC as the operational ozonesonde for the Payerne Aerological Station, Switzerland. The different factors of the ozonesonde data processing are considered and their influences on the profile of the difference are evaluated. The analysis of the ozone difference between the BM and the ECC ozonesonde data shows good agreement between the two sonde types. The profile of the ozone difference is limited to ±5% (±0.3 mPa) from the ground to 32 km. The analysis confirms the appropriateness of the standard BM data processing method and the usefulness of the normalization of the ozonesonde data. The conclusions of the extended dual flight campaigns are corroborated by the analysis of the time series of the Payerne soundings for the periods of 5 years before and after the change from BM to ECC which occurred in September 2002. No significant discontinuity can be identified in 2002 attributable to the change of sonde.
Quantitative separation of the directly‐driven and unloading components of the ionospheric electric field
Authors: Sun W. , Zhou X.‐Y. , Du A.
Published: July 2008

It is well known that the ionospheric electric field turns to southward in the auroral zone midnight sector at a substorm expansion phase onset. This letter reports a study of quantitatively separating the southward electric field (Es) from the total electric field by using the Natural Orthogonal Components (NOC) algorithm. The Es will be regarded as an unloading component of substorms. The westward component of the electric filed (Ew) in the midnight sector, which is associated with two‐cell convection, is identified as a directly driven component of substorms. Separated results for the event on April 18, 2002 are shown in the present study, which are characterized as a sawtooth event. It is found that the Es increased significantly to 30–40 mV/m during substorm expansion phases. Substorms may not develop if Es/Ew < 1 and Es < ∼30 mV/m during the sawtooth event.
Lack of correlation between chlorophyll a and cloud droplet effective radius in shallow marine clouds
Authors: Miller Matthew A. , Yuter Sandra E.
Published: July 2008

The hypothesis that areas of high oceanic productivity affect the physical properties of shallow marine clouds via the production of secondary organic aerosols is evaluated using satellite data. The correlation between chlorophyll a concentrations, an indication of oceanic productivity, and low cloud droplet liquid phase effective radius (Re) is examined for several ocean regions and time periods. While a strong correlation between chlorophyll a and low Re can occur for specific periods in some locations, the correlation is not reproducible in other regions and time periods. The intermittent correlation between high concentrations of chlorophyll a and low Re is a coincidence and is not representative of a dominant, monotonic, causative relation between secondary organic aerosols and marine shallow cloud properties.
Smooth muscle α1D‐adrenoceptors mediate phenylephrine‐induced vasoconstriction and increases in endothelial cell Ca2+in hamster cremaster arterioles
Authors: Jackson W F , Boerman E M , Lange E J , Lundback S S , Cohen K D
Published: July 2008

Background and purpose:

α1‐Adrenoceptor agonists induce Ca2+‐transients in endothelial cells (ECs) of arterioles. However, the presence of α1‐adrenoceptors on arteriolar ECs has not been excluded, and the identity of α1‐adrenoceptor subtypes in arterioles only has been inferred from pharmacology. Therefore, we determined which subtypes were expressed by vascular smooth muscle cells (VSMCs) and ECs, and which subtype mediated α1‐adrenoceptor‐induced constriction.

Experimental approach:

EC Ca2+‐transients in isolated, cannulated hamster cremasteric arterioles or freshly isolated ECs were studied using Fura 2. Arteriolar diameter was measured by video microscopy. α1‐Adrenoceptor expression was assessed by western blot of whole‐arteriolar homogenates and real‐time RT‐PCR on enzymatically isolated VSMCs and ECs.

Key results:

Phenylephrine‐induced constriction and EC Ca2+‐transients were abolished by the α1‐adrenoceptor antagonist prazosin (30 nM) in arterioles. Phenylephrine‐induced constriction was inhibited by the α1D‐adrenoceptor antagonist BMY 7378 (KB=2.96 nM) and the α1A‐adrenoceptor antagonist 5‐methylurapidil (KB=4.08 nM), suggesting a significant role for α1D‐adrenoceptors. Western blots confirmed α1D‐adrenoceptor expression, but did not detect α1A‐adrenoceptors. VSMCs expressed α1D‐ and α1A‐, but not α1B‐, adrenoceptor transcripts. No α1‐adrenoceptor transcripts were detected in ECs. Neither phenylephrine (10 μM) nor noradrenaline (0.1–1 μM) elicited Ca2+‐transients in freshly isolated ECs, whereas the endothelium‐dependent vasodilators methacholine (1 μM) and substance P (100 nM) consistently increased Ca2+.

Conclusions and implications:

We reject the hypothesis that hamster cremasteric arteriolar ECs express α1‐adrenoceptors and conclude that α1‐adrenoceptor agonists predominantly act on VSMC α1D‐adrenoceptors to cause vasoconstriction and a subsequent rise in EC Ca2+.

British Journal of Pharmacology(2008)155, 514–524; doi:10.1038/bjp.2008.276; published online 7 July 2008www.bjcancer.com
Dietary trace amine‐dependent vasoconstriction in porcine coronary artery
Authors: Herbert A A , Kidd E J , Broadley K J
Published: July 2008

Background and purpose:

The dietary trace amines tyramine and β‐phenylethylamine (β‐PEA) can increase blood pressure. However, the mechanisms involved in the vascular effect of trace amines have not been fully established. The purpose of this study was to evaluate whether trace amine‐dependent vasoconstriction was brought about by tyramine and β‐PEA acting as indirect sympathomimetic agents, as previously assumed, or whether trace amine‐dependent vasoconstriction could be mediated by recently discovered trace amine‐associated (TAA) receptors.

Experimental approach:

The responses to p‐tyramine and β‐PEA were investigated in vitro in rings of the left anterior descending coronary arteries of pigs.

Key results:

p‐Tyramine induced a concentration‐dependent (0.1–3 mM) vasoconstriction. The maximum response and pD2 value for p‐tyramine was unaffected by endothelium removal or pre‐treatment with antagonists for adrenoceptors, histamine, dopamine or 5‐HT receptors. β‐PEA also produced a concentration‐dependent (0.3–10 mM) vasoconstriction which was unaffected by endothelium removal, β‐adrenoceptor or 5‐HT receptor antagonists. A substantial, but reduced, response to β‐PEA was obtained in the presence of prazosin (α1‐adrenoceptor antagonist), haloperidol (D2/D3 dopamine receptor antagonist) or mepyramine (H1 histamine receptor antagonist). The pD2 value for β‐PEA was unaffected by any of the antagonists tested.

Conclusions and implications:

Vasoconstriction induced by p‐tyramine does not involve an indirect sympathomimetic effect, although vasoconstriction caused by β‐PEA may occur, in part, by this mechanism. We therefore propose that trace amine‐dependent vasoconstriction is mediated by phenylethylamine‐specific receptors, which are closely related to or identical to TAA receptors. These receptors could provide a target for new antihypertensive therapies.

British Journal of Pharmacology (2008) 155, 525–534; doi:10.1038/bjp.2008.286; published online 7 July 2008
Targeting airway inflammation: PMX464 and the epithelial bulls eye
Authors: Sexton D W
Published: July 2008

Increasing evidence places the epithelial cell at the centre of inflammatory processes in human airways. Crucial to this function and the maintenance of inflammatory homoeostasis is a balanced oxidant–antioxidant status in the airway, in part controlled by thioredoxin and thioredoxin reductase, which together can alter the NF‐κB pathway. PMX464, a thiol‐reactive quinol and putative thioredoxin inhibitor, has been investigated in endothelial cells, fibroblasts and colorectal cancer cell lines but in the present issue of the BJP, these investigations were extended to A549 airway epithelial cells. Thioredoxin inhibition was confirmed as was NF‐κB and IKK suppression but siRNA knockdown of thioredoxin did not alter inflammatory marker expression or activity, suggesting that PMX464 has targets other than thioredoxin. Future consolidation of this evidence will involve concomitant knockdown of thioredoxin reductase, the use of primary airway epithelial cells and, potentially, the employment of three‐dimensional (3D) culture systems for both A549 and primary cells.

British Journal of Pharmacology (2008) 155, 620–622; doi:fn1; published online 7 July 2008
Deciphering the functional role of endothelial junctions by using in vivo models
Authors: Nyqvist Daniel , Giampietro Costanza , Dejana Elisabetta
Published: July 2008

Endothelial cell‐to‐cell junctions are vital for the formation and integrity of blood vessels. The main adhesive junctional complexes in endothelial cells, adherens junctions and tight junctions, are formed by transmembrane adhesive proteins that are linked to intracellular signalling partners and cytoskeletal‐binding proteins. Gene inactivation and blocking antibodies in mouse models have revealed some of the functions of the individual junctional components in vivo, and are increasing our understanding of the functional role of endothelial cell junctions in angiogenesis and vascular homeostasis. Adherens‐junction organization is required for correct vascular morphogenesis during embryo development. By contrast, the data available suggest that tight‐junction proteins are not essential for vascular development but are necessary for endothelial barrier function.
Arf family GTP loading is activated by, and generates, positive membrane curvature
Authors: Lundmark Richard , Doherty Gary J. , Vallis Yvonne , Peter Brian J. , McMahon Harvey T.
Published: July 2008

Small G-proteins belonging to the Arf (ADP-ribosylation factor) family serve as regulatory proteins for numerous cellular processes through GTP-dependent recruitment of effector molecules. In the present study we demonstrate that proteins in this family regulate, and are regulated by, membrane curvature. Arf1 and Arf6 were shown to load GTP in a membrane-curvature-dependent manner and stabilize, or further facilitate, changes in membrane curvature through the insertion of an amphipathic helix.
RETRACTED: Triplex-forming oligonucleotide–orthophenanthroline conjugates for efficient targeted genome modification
Authors: Cannata Fabio , Brunet Erika , Perrouault Loïc , Roig Victoria , Ait-Si-Ali Slimane , Asseline Ulysse , Concordet Jean-Paul , Giovannangeli Carine
Published: July 2008

The inefficiency of gene modification by homologous recombination can be overcome by the introduction of a double-strand break (DSB) in the target. Engineering the endonucleases needed, however, remains a challenging task that limits widespread application of nuclease-driven gene modification. We report here that conjugates of orthophenanthroline (OP), a DNA cleaving molecule, and triplex-forming oligonucleotides (TFOs), known to bind specific DNA sequences, are synthetic nucleases efficient at stimulating targeted genome modification. We show that in cultured cells, OP-TFO conjugates induce targeted DSBs. An OP-TFO with a unique target was highly efficient, and mutations at the target site were found in ≈10% of treated cells, including small deletions most likely introduced during DSB repair by nonhomologous end joining. Importantly, we found that when homologous donor DNA was cotransfected, targeted gene modification took place in >1.5% of treated cells. Because triplex-forming sequences are frequent in human and mouse genes, OP-TFO conjugates therefore constitute an important class of site-specific nucleases for targeted gene modification. Harnessing DNA-damaging molecules to predetermined genomic sites, as achieved here, should also provide inroads into mechanisms of DNA repair and cancer.
Cellular and molecular effects of nonreciprocal chromosome translocations in
Saccharomyces cerevisiae
Authors: Nikitin Dmitri , Tosato Valentina , Zavec Apolonija Bedina , Bruschi Carlo V.
Published: July 2008

Saccharomyces cerevisiae
strains harboring a nonreciprocal, bridge-induced translocation (BIT) between chromosomes VIII and XV exhibited an abnormal phenotype comprising elongated buds and multibudded, unevenly nucleated pseudohyphae. In these cells, we found evidence of molecular effects elicited by the translocation event and specific for its particular genomic location. Expression of genes flanking both translocation breakpoints increased up to five times, correlating with an increased RNA polymerase II binding to their promoters and with their histone acetylation pattern. Microarray data, CHEF, and quantitative PCR confirmed the data on the dosage of genes present on the chromosomal regions involved in the translocation, indicating that telomeric fragments were either duplicated or integrated mostly on chromosome XI. FACS analysis revealed that the majority of translocant cells were blocked in G
1
phase and a few of them in G
2
. Some cells showed a posttranslational decrease of cyclin B1, in agreement with elongated buds diagnostic of a G
2
/M phase arrest. The actin1 protein was in some cases modified, possibly explaining the abnormal morphology of the cells. Together with the decrease in Rad53p and the lack of its phosphorylation, these results indicate that these cells have undergone adaptation after checkpoint-mediated G
2
/M arrest after chromosome translocation. These BIT translocants could serve as model systems to understand further the cellular and molecular effects of chromosome translocation and provide fundamental information on its etiology of neoplastic transformation in mammals.
RETRACTED: Glucose regulates the effects of leptin on hypothalamic POMC neurons
Authors: Ma Xiaosong , Zubcevic Lejla , Ashcroft Frances M.
Published: July 2008

Leptin is believed to exert its potent appetite-suppressing effects via stimulation of hypothalamic anorexigenic proopiomelanocortin (POMC)-containing neurons and inhibition of orexigenic agouti-related protein (AgRP) neurons. We show here that at 11 mM glucose leptin excites POMC cells. At 5 mM glucose, however, leptin hyperpolarizes POMC neurons and suppresses action potential firing, by producing a greater decrease in excitatory synaptic tone than inhibitory tone. These results argue that when glucose is low (5 mM or less) AgRP neurons will be more important for mediating the anorectic effects of leptin than POMC cells. However, at high glucose concentrations (11 mM), activation of POMC cells may contribute to the appetite-suppressing effects of leptin. Our data also suggest the regulation of neuropeptide efficacy as a novel function of hypothalamic glucose sensing.
The implications of human metabolic network topology for disease comorbidity
Authors: Lee D.-S. , Park J. , Kay K. A. , Christakis N. A. , Oltvai Z. N. , Barabási A.-L.
Published: July 2008

Most diseases are the consequence of the breakdown of cellular processes, but the relationships among genetic/epigenetic defects, the molecular interaction networks underlying them, and the disease phenotypes remain poorly understood. To gain insights into such relationships, here we constructed a bipartite human disease association network in which nodes are diseases and two diseases are linked if mutated enzymes associated with them catalyze adjacent metabolic reactions. We find that connected disease pairs display higher correlated reaction flux rate, corresponding enzyme-encoding gene coexpression, and higher comorbidity than those that have no metabolic link between them. Furthermore, the more connected a disease is to other diseases, the higher is its prevalence and associated mortality rate. The network topology-based approach also helps to uncover potential mechanisms that contribute to their shared pathophysiology. Thus, the structure and modeled function of the human metabolic network can provide insights into disease comorbidity, with potentially important consequences for disease diagnosis and prevention.
A myosin motor that selects bundled actin for motility
Authors: Nagy Stanislav , Ricca Benjamin L. , Norstrom Melanie F. , Courson David S. , Brawley Crista M. , Smithback Philip A. , Rock Ronald S.
Published: July 2008

Eukaryotic cells organize their contents through trafficking along cytoskeletal filaments. The leading edge of a typical metazoan cytoskeleton consists of a dense and complex arrangement of cortical actin. A dendritic mesh is found across the broad lamellopodium, with long parallel bundles at microspikes and filopodia. It is currently unclear whether and how myosin motors identify the few actin filaments that lead to the correct destination, when presented with many similar alternatives within the cortex. Here we show that myosin X, an actin-based motor that concentrates at the distal tips of filopodia, selects the fascin-actin bundle at the filopodial core for motility. Myosin X moves individual actin filaments poorly
in vitro
, often supercoiling actin into plectonemes. However, single myosin X motors move robustly and processively along fascin-actin bundles. This selection requires only parallel, closely spaced filaments, as myosin X is also processive on artificial actin bundles formed by molecular crowding. Myosin X filopodial localization is perturbed in fascin-depleted HeLa cells, demonstrating that fascin bundles also direct motility
in vivo
. Our results demonstrate that myosin X recognizes the local structural arrangement of filaments in long bundles, providing a mechanism for sorting cargo to distant target sites.
Sirt1 protects against high-fat diet-induced metabolic damage
Authors: Pfluger Paul T. , Herranz Daniel , Velasco-Miguel Susana , Serrano Manuel , Tschöp Matthias H.
Published: July 2008

The identification of new pharmacological approaches to effectively prevent, treat, and cure the metabolic syndrome is of crucial importance. Excessive exposure to dietary lipids causes inflammatory responses, deranges the homeostasis of cellular metabolism, and is believed to constitute a key initiator of the metabolic syndrome. Mammalian Sirt1 is a protein deacetylase that has been involved in resveratrol-mediated protection from high-fat diet-induced metabolic damage, but direct proof for the implication of Sirt1 has remained elusive. Here, we report that mice with moderate overexpression of Sirt1 under the control of its natural promoter exhibit fat mass gain similar to wild-type controls when exposed to a high-fat diet. Higher energy expenditure appears to be compensated by a parallel increase in food intake. Interestingly, transgenic Sirt1 mice under a high-fat diet show lower lipid-induced inflammation along with better glucose tolerance, and are almost entirely protected from hepatic steatosis. We present data indicating that such beneficial effects of Sirt1 are due to at least two mechanisms: induction of antioxidant proteins MnSOD and Nrf1, possibly via stimulation of PGC1α, and lower activation of proinflammatory cytokines, such as TNFα and IL-6, via down-modulation of NFκB activity. Together, these results provide direct proof of the protective potential of Sirt1 against the metabolic consequences of chronic exposure to a high-fat diet.
Evolution of the phospho-tyrosine signaling machinery in premetazoan lineages
Authors: Pincus David , Letunic Ivica , Bork Peer , Lim Wendell A.
Published: July 2008

Multicellular animals use a three-part molecular toolkit to mediate phospho-tyrosine signaling: Tyrosine kinases (TyrK), protein tyrosine phosphatases (PTP), and Src Homology 2 (SH2) domains function, respectively, as “writers,” “erasers,” and “readers” of phospho-tyrosine modifications. How did this system of three components evolve, given their interdependent function? Here, we examine the usage of these components in 41 eukaryotic genomes, including the newly sequenced genome of the choanoflagellate,
Monosiga brevicollis
, the closest known unicellular relative to metazoans. This analysis indicates that SH2 and PTP domains likely evolved earliest—a handful of these domains are found in premetazoan eukaryotes lacking tyrosine kinases, most likely to deal with limited tyrosine phosphorylation cross-catalyzed by promiscuous Ser/Thr kinases. Modern TyrK proteins, however, are only observed in two lineages, metazoans and choanoflagellates. These two lineages show a dramatic coexpansion of all three domain families. Concurrent expansion of the three domain families is consistent with a stepwise evolutionary model in which preexisting SH2 and PTP domains were of limited utility until the appearance of the TyrK domain in the last common ancestor of metazoans and choanoflagellates. The emergence of the full three-component signaling system, with its dramatically increased encoding potential, may have contributed to the advent of metazoan multicellularity.
Integration of auxin and brassinosteroid pathways by Auxin Response Factor 2
Authors: Vert Grégory , Walcher Cristina L. , Chory Joanne , Nemhauser Jennifer L.
Published: July 2008

Plant form is shaped by a complex network of intrinsic and extrinsic signals. Light-directed growth of seedlings (photomorphogenesis) depends on the coordination of several hormone signals, including brassinosteroids (BRs) and auxin. Although the close relationship between BRs and auxin has been widely reported, the molecular mechanism for combinatorial control of shared target genes has remained elusive. Here we demonstrate that BRs synergistically increase seedling sensitivity to auxin and show that combined treatment with both hormones can increase the magnitude and duration of gene expression. Moreover, we describe a direct connection between the BR-regulated BIN2 kinase and ARF2, a member of the Auxin Response Factor family of transcriptional regulators. Phosphorylation by BIN2 results in loss of ARF2 DNA binding and repression activities.arf2mutants are less sensitive to changes in endogenous BR levels, whereas a large proportion of genes affected in anarf2background are returned to near wild-type levels by altering BR biosynthesis. Together, these data suggest a model where BIN2 increases expression of auxin-induced genes by directly inactivating repressor ARFs, leading to synergistic increases in transcription.
Autocrine regulation of
mda
-7/IL-24 mediates cancer-specific apoptosis
Authors: Sauane Moira , Su Zao-zhong , Gupta Pankaj , Lebedeva Irina V. , Dent Paul , Sarkar Devanand , Fisher Paul B.
Published: July 2008

A noteworthy aspect of melanoma differentiation-associated gene-7/interleukin-24 (
mda
-7/IL-24) as a cancer therapeutic is its ability to selectively kill cancer cells without harming normal cells. Intracellular MDA-7/IL-24 protein, generated from an adenovirus expressing
mda
-7/IL-24 (Ad.
mda
-7), induces cancer-specific apoptosis by inducing an endoplasmic reticulum (ER) stress response. Secreted MDA-7/IL-24 protein, generated from cells infected with Ad.
mda
-7, induces growth inhibition and apoptosis in surrounding noninfected cancer cells but not in normal cells, thus exerting an anti-tumor “bystander” effect. The present studies reveal a provocative finding that recombinant MDA-7/IL-24 protein can robustly induce expression of endogenous
mda
-7/IL-24, which generates the signaling events necessary for bystander killing. To evaluate the mechanism underlying this positive autocrine feedback loop, we show that MDA-7/IL-24 protein induces stabilization of its own mRNA without activating its promoter. Furthermore, this posttranscriptional effect depends on
de novo
protein synthesis. As a consequence of this autocrine feedback loop MDA-7/IL-24 protein induces sustained ER stress as evidenced by expression of ER stress markers (BiP/GRP78, GRP94, GADD153, and phospho-eIF2α) and reactive oxygen species production, indicating that both intracellular and secreted proteins activate similar signaling pathways to induce apoptosis. Thus, our results clarify the molecular mechanism by which secreted MDA-7/IL-24 protein (generated from Ad.
mda-7
-infected cells) exerts cancer-specific killing.
Visions of visibility: LGBT communities in Turin
Authors: Ross Charlotte
Published: July 2008

Recent anti-discrimination campaigns by lesbian, gay, bisexual and transsexual (LGBT) activists in Italy have increased the visibility of these communities and individuals, but have not resulted in the desired improvements to legislation. In light of this situation, this article analyses modalities of ‘visibility’ as defined and desired by the active LGBT community in Turin, host city for National Pride 2006. The Pride committee scheduled an unprecedentedly ‘visible’ year-long programme of consciousness-raising and cultural events that went far beyond the more usual one-day march. Drawing on a series of interviews with members of the committee and of the lesbian community conducted in Turin in March and June 2006, the discussion explores social, cultural and political visibility in this LGBT community as it hosted National Pride.
The challenges to democracy and citizenship surrounding the vote to Italians overseas
Authors: Battiston Simone , Mascitelli Bruno
Published: July 2008

In 2003, a presidential decree enacted legislation guaranteeing Italian voters overseas the right to postal voting as well as parliamentary representation within their respective electoral constituency. The electoral weight of the overseas-based constituent had a remarkable effect on the 2006 election results. In the tightest vote in the Republic's history, the vote of overseas Italians, which was one of the decisive features of the election, helped provide the winning centre-left coalition with a slender majority in the Senate. Election results notwithstanding, the question of whether to grant the vote to Italians overseas has faced challenges of a procedural, normative and political nature. What may have been initially seen as a democratic right may well be cast aside as it poses challenges to overseas electoral relationships with the Italian national polity, Italian citizenship and multinational allegiances, diasporic identity, electoral participation and political representation in homeland political institutions. The overseas vote for Italians may be contested further in the near future, which could translate into a radical rethink of its validity and democratic global extension.
The second Prodi government and Italian foreign policy: New and improved or the same wrapped up differently?
Authors: Croci Osvaldo
Published: July 2008

This article examines whether Italian foreign policy has undergone significant and substantial changes under the second Prodi government. The first part identifies the variables affecting continuity and change in a country's foreign policy and addresses the question of the conditions under which one can expect changes as a result of a change in government, and the conditions under which continuity is instead more likely. The second part looks at the second Prodi government's foreign policy on a number of topical issues, most of which were also faced by the Berlusconi government, to see to what extent the Prodi government's approach to foreign policy indeed changed from that of its predecessor. The article concludes that the Prodi government did not change Italian foreign policy in any substantial manner; differences existed only in the way the new government occasionally chose to present and justify its policies publicly.
Gulliver unbound. Possible electoral reforms and the 2008 Italian election: Towards an end to ‘fragmented bipolarity’?
Authors: Floridia Antonio
Published: July 2008

This article considers the systemic effects of the electoral reform approved by the centre-right in December 2005, and the factors that led to the crisis of the Prodi government, highlighting the way in which the issue of electoral reform and the likelihood of an electoral referendum contributed decisively to the breakdown of the fragile coalition maintaining the Prodi government in office. The article then analyses the ‘game’ surrounding possible electoral reforms, examining the interweaving of the preferences and vetoes of the various political actors, showing how these were influenced by the strategic aims of each actor and by the process of re-structuring of the party system. Finally, the new configuration of the political supply as it took shape in the run up to the 2008 general election is analysed, showing how this new format derives from the actors’ strategic adaptation to the electoral rules in force, and how the election may signal the end of a period of Italian politics marked by ‘fragmented bipolarity’.
Surfing and trying to keep afloat: The political communication process in a highly fragmented coalition led by a ‘Great Mediator’
Authors: Roncarolo Franca , Belluati Marinella
Published: July 2008

This article analyses the experience of the second Prodi government from the standpoint of its political communication. The opening part contextualises the case by placing it within the broader framework of coalition governments generally, and briefly outlines the critical elements that, in Italy, prevent any majority from making a genuinely strategic use of communication in the policy-making process. The second part focuses on Prodi's poor communication, highlighting both its limits and the attempts at improvement made by the leader and his staff in 2007. Finally, the third part examines the journalistic coverage of the centre-left majority and considers the trend in public approval for the premier and the government, emphasising the problems that emerged on each side.
Watermarking sexually reproducing diploid organisms
Authors: Heider Dominik , Kessler Daniel , Barnekow Angelika
Published: July 2008

Summary: DNA watermarks are used for hiding messages or for authenticating genetically modified organisms. Recently, we presented an algorithm called DNA-Crypt for generating DNA-based watermarks that can be integrated into the genome by using the characteristics of the degenerative genetic code. DNA-Crypt generates the watermark by replacing single bases and thus creating synonymous codons that encrypt the hidden information. Mutations within the integrated DNA sequence can be corrected using several mutation correction codes, to keep the hidden information intact. This method has successfully been tested in asexually replicating organisms like bacteria or yeast, where the watermark is duplicated with every cell division. It has been shown that DNA watermarks produced by DNA-Crypt do not influence the transcription or translation of a protein. In sexually reproducing diploid organisms, additional problems can occur, e.g. recombination events can destroy hidden information. Using population predictions as well as statistical analyses we identified a coupled Y-chromosomal/mitochondrial DNA watermarking procedure as the most appropriate for diploid organisms. We developed a mitochondria adapted version of DNA-Crypt, which is called Project Mito that can be used in combination with the original program.

Availability:  http://www.uni-muenster.de/Biologie.NeuroVer/Tumorbiologie/DNA-Crypt/index.html

Contact:  barneko@uni-muenster.de

Password: WWUTB

Requirements: Java 5.0 or higher

Supplementary information:  Supplementary data are available at Bioinformatics online.
Very small mobile repeated elements in cyanobacterial genomes
Authors: Elhai Jeff , Kato Michiko , Cousins Sarah , Lindblad Peter , Costa José Luis
Published: July 2008

Mobile DNA elements play a major role in genome plasticity and other evolutionary processes, an insight gained primarily through the study of transposons and retrotransposons (generally ∼1000 nt or longer). These elements spawn smaller parasitic versions (generally >100 nt) that propagate through proteins encoded by the full elements. Highly repeated sequences smaller than 100 nt have been described, but they are either nonmobile or their origins are not known. We have surveyed the genome of the multicellular cyanobacterium, Nostoc punctiforme, and its relatives for small dispersed repeat (SDR) sequences and have identified eight families in the range of from 21 to 27 nucleotides. Three of the families (SDR4, SDR5, and SDR6), despite little sequence similarity, share a common predicted secondary structure, a conclusion supported by patterns of compensatory mutations. The SDR elements are found in a diverse set of contexts, often embedded within tandemly repeated heptameric sequences or within minitransposons. One element (SDR5) is found exclusively within instances of an octamer, HIP1, that is highly over-represented in the genomes of many cyanobacteria. Two elements (SDR1 and SDR4) often are found within copies of themselves, producing complex nested insertions. An analysis of SDR elements within cyanobacterial genomes indicate that they are essentially confined to a coherent subgroup. The evidence indicates that some of the SDR elements, probably working through RNA intermediates, have been mobile in recent evolutionary time, making them perhaps the smallest known mobile elements.
A Novel Role for Protein Farnesylation in Plant Innate Immunity
Authors: Goritschnig Sandra , Weihmann Tabea , Zhang Yuelin , Fobert Pierre , McCourt Peter , Li Xin
Published: July 2008

Plants utilize tightly regulated mechanisms to defend themselves against pathogens. Initial recognition results in activation of specific Resistance (R) proteins that trigger downstream immune responses, in which the signaling networks remain largely unknown. A point mutation in SUPPRESSOR OF NPR1 CONSTITUTIVE1 (SNC1), a RESISTANCE TO PERONOSPORA PARASITICA4 R gene homolog, renders plants constitutively resistant to virulent pathogens. Genetic suppressors of snc1 may carry mutations in genes encoding novel signaling components downstream of activated R proteins. One such suppressor was identified as a novel loss-of-function allele of ENHANCED RESPONSE TO ABSCISIC ACID1 (ERA1), which encodes the β-subunit of protein farnesyltransferase. Protein farnesylation involves attachment of C15-prenyl residues to the carboxyl termini of specific target proteins. Mutant era1 plants display enhanced susceptibility to virulent bacterial and oomycete pathogens, implying a role for farnesylation in basal defense. In addition to its role in snc1-mediated resistance, era1 affects several other R-protein-mediated resistance responses against bacteria and oomycetes. ERA1 acts partly independent of abscisic acid and additively with the resistance regulator NON-EXPRESSOR OF PR GENES1 in the signaling network. Defects in geranylgeranyl transferase I, a protein modification similar to farnesylation, do not affect resistance responses, indicating that farnesylation is most likely specifically required in plant defense signaling. Taken together, we present a novel role for farnesyltransferase in plant-pathogen interactions, suggesting the importance of protein farnesylation, which contributes to the specificity and efficacy of signal transduction events.
A Role for AtWRKY23 in Feeding Site Establishment of Plant-Parasitic Nematodes
Authors: Grunewald Wim , Karimi Mansour , Wieczorek Krzysztof , Van de Cappelle Elke , Wischnitzki Elisabeth , Grundler Florian , Inzé Dirk , Beeckman Tom , Gheysen Godelieve
Published: July 2008

During the interaction between sedentary plant-parasitic nematodes and their host, complex morphological and physiological changes occur in the infected plant tissue, finally resulting in the establishment of a nematode feeding site. This cellular transformation is the result of altered plant gene expression most likely induced by proteins injected in the plant cell by the nematode. Here, we report on the identification of a WRKY transcription factor expressed during nematode infection. Using both promoter-reporter gene fusions and in situ reverse transcription-polymerase chain reaction, we could show that AtWRKY23 is expressed during the early stages of feeding site establishment. Knocking down the expression of WRKY23 resulted in lower infection of the cyst nematode Heterodera schachtii. WRKY23 is an auxin-inducible gene and in uninfected plants WRKY23 acts downstream of the Aux/IAA protein SLR/IAA14. Although auxin is known to be involved in feeding site formation, our results suggest that, during early stages, auxin-independent signals might be at play to activate the initial expression of WRKY23.