bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the Magnetospheres of Rapidly Rotating B-type Stars
Authors: Fletcher C. L. , Petit V. , Nazé Y. , Wade G. A. , Townsend R. H. , Owocki S. P. , Cohen D. H. , David-Uraz A. , Shultz M.
Published: July 2017

Recent spectropolarimetric surveys of bright, hot stars have found that ~10% of OB-type stars contain strong (mostly dipolar) surface magnetic fields (~kG). The prominent paradigm describing the interaction between the stellar winds and the surface magnetic field is the magnetically confined wind shock (MCWS) model. In this model, the stellar wind plasma is forced to move along the closed field loops of the magnetic field, colliding at the magnetic equator, and creating a shock. As the shocked material cools radiatively it will emit X-rays. Therefore, X-ray spectroscopy is a key tool in detecting and characterizing the hot wind material confined by the magnetic fields of these stars. Some B-type stars are found to have very short rotational periods. The effects of the rapid rotation on the X-ray production within the magnetosphere have yet to be explored in detail. The added centrifugal force due to rapid rotation is predicted to cause faster wind outflows along the field lines, leading to higher shock temperatures and harder X-rays. However, this is not observed in all rapidly rotating magnetic B-type stars. In order to address this from a theoretical point of view, we use the X-ray Analytical Dynamical Magnetosphere (XADM) model, originally developed for slow rotators, with an implementation of new rapid rotational physics. Using X-ray spectroscopy from ESA’s XMM-Newton space telescope, we observed 5 rapidly rotating B-types stars to add to the previous list of observations. Comparing the observed X-ray luminosity and hardness ratio to that predicted by the XADM allows us to determine the role the added centrifugal force plays in the magnetospheric X-ray emission of these stars.
Asymmetric Core-collapse of a Rapidly-rotating Massive Star
Authors: Gilkis Avishai
Published: July 2017

I find high turbulent shearing in a neutron-rich accretion disk surrounding a proto-neutron star formed at the collapse of a rapidly-rotating MZAMS = 54M⊙ star. These might be features of superluminous supernovae powered by jets and/or magnetar spin-down.
Kinematics of SNRs CTB 109 and G206.9+2.3
Authors: Rosado Margarita , Sánchez-Cruces Mónica , Ambrocio-Cruz Patricia
Published: July 2017

We present results of optical observations in the lines of Hα and [SII] (λ 6717 and 6731 Å) obtained with the UNAM Scanning Fabry-Perot Interferometer PUMA (Rosado et al. 1995,RMxAASC, 3, 263 ) aimed at obtaining the kinematical distance, shock velocity and other important parameters of two supernova remnants (SNRs) with optical counterparts. We discuss on how kinematical distances thus obtained fit with other distance determinations. The studied SNRs are CTB 109 (SNR G109.1 − 1.0) hosting a magnetar (Sánchez-Cruces et al. 2017, in preparation) and the SNR G206.9 + 2.3 (Ambrocio-Cruz et al. 2014,RMxAA, 50, 323), a typical supernova remnant, to have a comparison. In Fig. 1 is depicted the [SII] line emission of two filaments of the optical counterpart of SNR CTB 109. We find complex radial velocity profiles obtained with the Fabry-Perot interferometer, revealing the presence of different velocity components. From these velocity profiles we obtain the kinematical distance, an expansion velocity of 188 km/s and an initial energy of 8.1 x 1050 ergs. These values are rather typical of other SNRs regardless that SNR CTB 109 hosts a magnetar. Thus, the mechanical energy delivered in the supernova explosion forming the magnetar does not seem to impact more than other SNe explosions the interstellar medium. This work has been funded by grants IN103116 and 253085 from DGAPA-UNAM and CONACYT, respectively.
New Insights into the Puzzling P-Cygni Profiles of Magnetic Massive Stars
Authors: Erba Christiana , David-Uraz Alexandre , Petit Véronique , Owocki Stanley P.
Published: July 2017

Magnetic massive stars comprise approximately 10% of the total OB star population. Modern spectropolarimetry shows these stars host strong, stable, large-scale, often nearly dipolar surface magnetic fields of 1 kG or more. These global magnetic fields trap and deflect outflowing stellar wind material, forming an anisotropic magnetosphere that can be probed with wind-sensitive UV resonance lines. Recent HST UV spectra of NGC 1624-2, the most magnetic O star observed to date, show atypically unsaturated P-Cygni profiles in the Civ resonant doublet, as well as a distinct variation with rotational phase. We examine the effect of non-radial, magnetically-channeled wind outflow on P-Cygni line formation, using a Sobolev Exact Integration (SEI) approach for direct comparison with HST UV spectra of NGC 1624-2. We demonstrate that the addition of a magnetic field desaturates the absorption trough of the P-Cygni profiles, but further efforts are needed to fully account for the observed line profile variation. Our study thus provides a first step toward a broader understanding of how strong magnetic fields affect mass loss diagnostics from UV lines.
SN 2015bh: an LBV becomes NGC 2770s fourth SN. . . or not?
Authors: Thöne Christina C. , de Ugarte Postigo Antonio , Leloudas Giorgos
Published: July 2017

Massive stars in the final phases of their lives frequently expel large amounts of material. An interesting example is SN 2009ip that varied in brightness years before its possible core-collapse. Here we present SN 2015bh in NGC 2770 that shows striking similarities to SN 2009ip. It experienced frequent variabilities for 21 years before a smaller precursor and the “main event” in May 2015. Its spectra are consistent with an LBV during the outburst phase and show a complex P-Cygni profile during the main event. Both SN 2009ip and 2015bh were always situated red-wards of LBVs in outburst in the HR diagram. Their final fate is currently still uncertain, SN 2009ip, however, is now fainter than in pre-explosion observations. If the star survives this event it is undoubtedly altered, and we suggest that these “zombie stars” could be LBVs evolving into a Wolf-Rayet (WR) star over a very short timescale.
360-degree videos: a new visualization technique for astrophysical simulations
Authors: Russell Christopher M. P.
Published: July 2017

360-degree videos are a new type of movie that renders over all 4π steradian. Video sharing sites such as YouTube now allow this unique content to be shared via virtual reality (VR) goggles, hand-held smartphones/tablets, and computers. Creating 360° videos from astrophysical simulations is not only a new way to view these simulations as you are immersed in them, but is also a way to create engaging content for outreach to the public. We present what we believe is the first 360° video of an astrophysical simulation: a hydrodynamics calculation of the central parsec of the Galactic centre. We also describe how to create such movies, and briefly comment on what new science can be extracted from astrophysical simulations using 360° videos.
Stellar wind measurements for Colliding Wind Binaries using X-ray observations
Authors: Sugawara Yasuharu , Maeda Yoshitomo , Tsuboi Yohko
Published: July 2017

We report the results of the stellar wind measurement for two colliding wind binaries. The X-ray spectrum is the best measurement tool for the hot postshock gas. By monitoring the changing of the the X-ray luminosity and column density along with the orbital phases, we derive the mass-loss rates of these stars.
Exposure to parental psychopathology and offspring's risk of suicide-related thoughts and behaviours: a systematic review
Authors: Goodday S. M. , Shuldiner J. , Bondy S. , Rhodes A. E.
Published: July 2017

Aims.

The primary objective of this systematic review was to identify and synthesise analytic studies examining the association between exposure to parental psychopathology in childhood and the nature of subsequent suicide-related thoughts (SRT) and suicide-related behaviour (SRB) (severity of ideation, planned/unplanned attempts/lethality) and to describe the direction, and magnitude of associations. The secondary objective was to determine if the associations from the primary objective differ by the type(s) and timing of parental psychopathology, sex/gender of the parent and child and is mediated by child psychiatric symptoms and family functioning.

Methods.

A systematic review was conducted using guidelines from the PRISMA statement. MEDLINE, CINAHL, EMBASE, psycINFO, Web of Science and grey literature sources were searched by two reviewers to March, 2017. Studies were included if they examined any parental psychopathology (Diagnostic and Statistical Manual of Mental Disorders criteria or equivalent) or SRT or SRB and offspring SRT or SRB occurring from birth <25 years of age.

Results.

Out of 10 231 studies identified, 54 were included for review. Studies were clinically and methodologically heterogeneous with none at low risk of bias (ROB). Nine studies with moderate ROB indicated a significantly increased risk of offspring SRT, suicide attempts (SA) and suicide among those exposed to maternal SA and suicide in childhood or adolescence. In the remaining 45 studies with higher ROB this association persisted. Several studies (67%) did not confirm that the exposure occurred in the offspring's childhood or adolescence. Findings were suggestive of a mediating effect of offspring psychiatric symptoms, however, few studies examined mediation and effect modification of contextual variables.

Conclusions.

Offspring exposed to maternal SA are at an increased risk of these same behaviours early in life. Prospective attention to the types and timing of maternal and paternal psychopathology and the intermediate pathways to offspring SRT and SRB onset is needed and could have implications for informing modifiable targets for early intervention and prevention.
A Fixed Mindset Leads to Negative Affect
Authors: King Ronnel B.
Published: July 2017

Abstract. The way individuals think about their intelligence (i.e., implicit theories of intelligence) powerfully shapes learning processes. However, not much is known about how implicit theories of intelligence are associated with subjective well-being. The aim of this study was to investigate the relationship between implicit theories of intelligence and subjective well-being as indexed by life satisfaction, positive affect, and (low levels of) negative affect. Study 1, a cross-sectional study, showed that entity theory of intelligence was negatively associated with life satisfaction and positively associated with negative affect. Study 2, a cross-lagged longitudinal study, showed that implicit theories and certain dimensions of subjective well-being were reciprocally related. Time 1 entity theory positively predicted subsequent negative affect, while Time 1 positive affect was negatively associated with T2 entity theory. Theoretical and practical implications are discussed.
Emerging paradigm of virtual-microscopy for histopathology diagnosis: survey of US and Canadian oral pathology trainees
Authors: Nwizu Ngozi N , Owosho Adepitan , Ogbureke Kalu U E
Published: July 2017

Objectives/Aims:

The application of virtual microscopy (VM) to research, pre-doctoral medical and dental educational training, and diagnostic surgical and anatomic pathology is well-documented but its application to the field of oral and maxillofacial pathology has not been explored. This is the first study to evaluate the enthusiasm and readiness of US-/Canada-based oral and maxillofacial pathology (OMFP) residents toward employing VM use over conventional microscopy (CM) for diagnostic purposes.

Materials and Methods:

All 46 current US-/Canada-based OMFP residents were invited to participate in an anonymous electronic survey via ‘Survey Monkey’ in 2015. The survey comprised sixteen multiple choice questions and two ‘free text’ questions.

Results:

14% of respondents of the 22 (48%) respondents who completed the survey indicated a willingness to substitute CM with VM in <5 years, and 33% within 10 years. 52% reported they would never substitute CM with VM. Approximately 10 and 57% of respondents thought VM will become an acceptable sole diagnostic tool in most centers within 5 and 10 years, respectively. These findings are irrespective of the fact that overall, 90% of respondents reported being familiar with VM use.

Discussion:

VM technology is unlikely to substitute CM in diagnostic oral and maxillofacial histopathology practice among future OMFP practitioners in the foreseeable future.
WWOX sensitises ovarian cancer cells to paclitaxel via modulation of the ER stress response
Authors: Janczar Szymon , Nautiyal Jaya , Xiao Yi , Curry Edward , Sun Mingjun , Zanini Elisa , Paige Adam JW , Gabra Hani
Published: July 2017

There are clear gaps in our understanding of genes and pathways through which cancer cells facilitate survival strategies as they become chemoresistant. Paclitaxel is used in the treatment of many cancers, but development of drug resistance is common. Along with being an antimitotic agent paclitaxel also activates endoplasmic reticulum (ER) stress. Here, we examine the role of WWOX (WW domain containing oxidoreductase), a gene frequently lost in several cancers, in mediating paclitaxel response. We examine the ER stress-mediated apoptotic response to paclitaxel in WWOX-transfected epithelial ovarian cancer (EOC) cells and following siRNA knockdown of WWOX. We show that WWOX-induced apoptosis following exposure of EOC cells to paclitaxel is related to ER stress and independent of the antimitotic action of taxanes. The apoptotic response to ER stress induced by WWOX re-expression could be reversed by WWOX siRNA in EOC cells. We report that paclitaxel treatment activates both the IRE-1 and PERK kinases and that the increase in paclitaxel-mediated cell death through WWOX is dependent on active ER stress pathway. Log-rank analysis of overall survival (OS) and progression-free survival (PFS) in two prominent EOC microarray data sets (Tothill and The Cancer Genome Atlas), encompassing ~800 patients in total, confirmed clinical relevance to our findings. High WWOX mRNA expression predicted longer OS and PFS in patients treated with paclitaxel, but not in patients who were treated with only cisplatin. The association of WWOX and survival was dependent on the expression level of glucose-related protein 78 (GRP78), a key ER stress marker in paclitaxel-treated patients. We conclude that WWOX sensitises EOC to paclitaxel via ER stress-induced apoptosis, and predicts clinical outcome in patients. Thus, ER stress response mechanisms could be targeted to overcome chemoresistance in cancer.
Biogeography and organic matter removal shape long-term effects of timber harvesting on forest soil microbial communities
Authors: Wilhelm Roland C , Cardenas Erick , Maas Kendra R , Leung Hilary , McNeil Larisa , Berch Shannon , Chapman William , Hope Graeme , Kranabetter J M , Dubé Stephane , Busse Matt , Fleming Robert , Hazlett Paul , Webster Kara L , Morris David , Scott D Andrew , Mohn William W
Published: July 2017

The growing demand for renewable, carbon-neutral materials and energy is leading to intensified forest land-use. The long-term ecological challenges associated with maintaining soil fertility in managed forests are not yet known, in part due to the complexity of soil microbial communities and the heterogeneity of forest soils. This study determined the long-term effects of timber harvesting, accompanied by varied organic matter (OM) removal, on bacterial and fungal soil populations in 11- to 17-year-old reforested coniferous plantations at 18 sites across North America. Analysis of highly replicated 16 S rRNA gene and ITS region pyrotag libraries and shotgun metagenomes demonstrated consistent changes in microbial communities in harvested plots that included the expansion of desiccation- and heat-tolerant organisms and decline in diversity of ectomycorrhizal fungi. However, the majority of taxa, including the most abundant and cosmopolitan groups, were unaffected by harvesting. Shifts in microbial populations that corresponded to increased temperature and soil dryness were moderated by OM retention, which also selected for sub-populations of fungal decomposers. Biogeographical differences in the distribution of taxa as well as local edaphic and environmental conditions produced substantial variation in the effects of harvesting. This extensive molecular-based investigation of forest soil advances our understanding of forest disturbance and lays the foundation for monitoring long-term impacts of timber harvesting.
Drought and host selection influence bacterial community dynamics in the grass root microbiome
Authors: Naylor Dan , DeGraaf Stephanie , Purdom Elizabeth , Coleman-Derr Devin
Published: July 2017

Root endophytes have been shown to have important roles in determining host fitness under periods of drought stress, and yet the effect of drought on the broader root endosphere bacterial community remains largely uncharacterized. In this study, we present phylogenetic profiles of bacterial communities associated with drought-treated root and rhizosphere tissues of 18 species of plants with varying degrees of drought tolerance belonging to the Poaceae family, including important crop plants. Through 16S rRNA gene profiling across two distinct watering regimes and two developmental time points, we demonstrate that there is a strong correlation between host phylogenetic distance and the microbiome dissimilarity within root tissues, and that drought weakens this correlation by inducing conserved shifts in bacterial community composition. We identify a significant enrichment in a wide variety of Actinobacteria during drought within the roots of all hosts, and demonstrate that this enrichment is higher within the root than it is in the surrounding environments. Furthermore, we show that this observed enrichment is the result of an absolute increase in Actinobacterial abundance and that previously hypothesized mechanisms for observed enrichments in Actinobacteria in drought-treated soils are unlikely to fully account for the phenomena observed here within the plant root.
Ice nucleation active bacteria in precipitation are genetically diverse and nucleate ice by employing different mechanisms
Authors: Failor K C , Schmale D G , Vinatzer B A , Monteil C L
Published: July 2017

A growing body of circumstantial evidence suggests that ice nucleation active (Ice+) bacteria contribute to the initiation of precipitation by heterologous freezing of super-cooled water in clouds. However, little is known about the concentration of Ice+ bacteria in precipitation, their genetic and phenotypic diversity, and their relationship to air mass trajectories and precipitation chemistry. In this study, 23 precipitation events were collected over 15 months in Virginia, USA. Air mass trajectories and water chemistry were determined and 33 134 isolates were screened for ice nucleation activity (INA) at −8 °C. Of 1144 isolates that tested positive during initial screening, 593 had confirmed INA at −8 °C in repeated tests. Concentrations of Ice+ strains in precipitation were found to range from 0 to 13 219 colony forming units per liter, with a mean of 384±147. Most Ice+ bacteria were identified as members of known and unknown Ice+ species in the Pseudomonadaceae, Enterobacteriaceae and Xanthomonadaceae families, which nucleate ice employing the well-characterized membrane-bound INA protein. Two Ice+ strains, however, were identified as Lysinibacillus, a Gram-positive genus not previously known to include Ice+ bacteria. INA of the Lysinibacillus strains is due to a nanometer-sized molecule that is heat resistant, lysozyme and proteinase resistant, and secreted. Ice+ bacteria and the INA mechanisms they employ are thus more diverse than expected. We discuss to what extent the concentration of culturable Ice+ bacteria in precipitation and the identification of a new heat-resistant biological INA mechanism support a role for Ice+ bacteria in the initiation of precipitation.
Long-range transport of airborne microbes over the global tropical and subtropical ocean
Authors: Mayol Eva , Arrieta Jesús M. , Jiménez Maria A. , Martínez-Asensio Adrián , Garcias-Bonet Neus , Dachs Jordi , González-Gaya Belén , Royer Sarah-J. , Benítez-Barrios Verónica M. , Fraile-Nuez Eugenio , Duarte Carlos M.
Published: July 2017

The atmosphere plays a fundamental role in the transport of microbes across the planet but it is often neglected as a microbial habitat. Although the ocean represents two thirds of the Earth’s surface, there is little information on the atmospheric microbial load over the open ocean. Here we provide a global estimate of microbial loads and air-sea exchanges over the tropical and subtropical oceans based on the data collected along the Malaspina 2010 Circumnavigation Expedition. Total loads of airborne prokaryotes and eukaryotes were estimated at 2.2 × 1021 and 2.1 × 1021 cells, respectively. Overall 33–68% of these microorganisms could be traced to a marine origin, being transported thousands of kilometres before re-entering the ocean. Moreover, our results show a substantial load of terrestrial microbes transported over the oceans, with abundances declining exponentially with distance from land and indicate that islands may act as stepping stones facilitating the transoceanic transport of terrestrial microbes.
Molecular characterization of breast cancer CTCs associated with brain metastasis
Authors: Boral Debasish , Vishnoi Monika , Liu Haowen N. , Yin Wei , Sprouse Marc L. , Scamardo Antonio , Hong David S. , Tan Tuan Z. , Thiery Jean P. , Chang Jenny C. , Marchetti Dario
Published: July 2017

The enumeration of EpCAM-positive circulating tumor cells (CTCs) has allowed estimation of overall metastatic burden in breast cancer patients. However, a thorough understanding of CTCs associated with breast cancer brain metastasis (BCBM) is necessary for early identification and evaluation of treatment response to BCBM. Here we report that BCBM CTCs is enriched in a distinct sub-population of cells identifiable by their biomarker expression and mutational content. Deriving from a comprehensive analysis of CTC transcriptomes, we discovered a unique “circulating tumor cell gene signature” that is distinct from primary breast cancer tissues. Further dissection of the circulating tumor cell gene signature identified signaling pathways associated with BCBM CTCs that may have roles in potentiating BCBM. This study proposes CTC biomarkers and signaling pathways implicated in BCBM that may be used either as a screening tool for brain micro-metastasis detection or for making rational treatment decisions and monitoring therapeutic response in patients with BCBM.
HIPP neurons in the dentate gyrus mediate the cholinergic modulation of background context memory salience
Authors: Raza Syed Ahsan , Albrecht Anne , Çalışkan Gürsel , Müller Bettina , Demiray Yunus Emre , Ludewig Susann , Meis Susanne , Faber Nicolai , Hartig Roland , Schraven Burkhart , Lessmann Volkmar , Schwegler Herbert , Stork Oliver
Published: July 2017

Cholinergic neuromodulation in the hippocampus controls the salience of background context memory acquired in the presence of elemental stimuli predicting an aversive reinforcement. With pharmacogenetic inhibition we here demonstrate that hilar perforant path-associated (HIPP) cells of the dentate gyrus mediate the devaluation of background context memory during Pavlovian fear conditioning. The salience adjustment is sensitive to reduction of hilar neuropeptide Y (NPY) expression via dominant negative CREB expression in HIPP cells and to acute blockage of NPY-Y1 receptors in the dentate gyrus during conditioning. We show that NPY transmission and HIPP cell activity contribute to inhibitory effects of acetylcholine in the dentate gyrus and that M1 muscarinic receptors mediate the cholinergic activation of HIPP cells as well as their control of background context salience. Our data provide evidence for a peptidergic local circuit in the dentate gyrus that mediates the cholinergic encoding of background context salience during fear memory acquisition.
Discovering the building blocks of atomic systems using machine learning: application to grain boundaries
Authors: Rosenbrock Conrad W. , Homer Eric R. , Csányi Gábor , Hart Gus L. W.
Published: July 2017

Machine learning has proven to be a valuable tool to approximate functions in high-dimensional spaces. Unfortunately, analysis of these models to extract the relevant physics is never as easy as applying machine learning to a large data set in the first place. Here we present a description of atomic systems that generates machine learning representations with a direct path to physical interpretation. As an example, we demonstrate its usefulness as a universal descriptor of grain boundary systems. Grain boundaries in crystalline materials are a quintessential example of a complex, high-dimensional system with broad impact on many physical properties including strength, ductility, corrosion resistance, crack resistance, and conductivity. In addition to modeling such properties, the method also provides insight into the physical “building blocks” that influence them. This opens the way to discover the underlying physics behind behaviors by understanding which building blocks map to particular properties. Once the structures are understood, they can then be optimized for desirable behaviors.
Structural Basis for the Mechanism of ATP-Dependent Acetone Carboxylation
Authors: Mus Florence , Eilers Brian J. , Alleman Alexander B. , Kabasakal Burak V. , Wells Jennifer N. , Murray James W. , Nocek Boguslaw P. , DuBois Jennifer L. , Peters John W.
Published: July 2017

Microorganisms use carboxylase enzymes to form new carbon-carbon bonds by introducing carbon dioxide gas (CO2) or its hydrated form, bicarbonate (HCO3−), into target molecules. Acetone carboxylases (ACs) catalyze the conversion of substrates acetone and HCO3− to form the product acetoacetate. Many bicarbonate-incorporating carboxylases rely on the organic cofactor biotin for the activation of bicarbonate. ACs contain metal ions but not organic cofactors, and use ATP to activate substrates through phosphorylation. How the enzyme coordinates these phosphorylation events and new C-C bond formation in the absence of biotin has remained a mystery since these enzymes were discovered. The first structural rationale for acetone carboxylation is presented here, focusing on the 360 kDa (αβγ)2 heterohexameric AC from Xanthobacter autotrophicus in the ligand-free, AMP-bound, and acetate coordinated states. These structures suggest successive steps in a catalytic cycle revealing that AC undergoes large conformational changes coupled to substrate activation by ATP to perform C-C bond ligation at a distant Mn center. These results illustrate a new chemical strategy for the conversion of CO2 into biomass, a process of great significance to the global carbon cycle.
Local opposite orientation preferences in V1: fMRI sensitivity to fine-grained pattern information
Authors: Alink Arjen , Walther Alexander , Krugliak Alexandra , Kriegeskorte Nikolaus
Published: July 2017

The orientation of a visual grating can be decoded from human primary visual cortex (V1) using functional magnetic resonance imaging (fMRI) at conventional resolutions (2–3 mm voxel width, 3T scanner). It is unclear to what extent this information originates from different spatial scales of neuronal selectivity, ranging from orientation columns to global areal maps. According to the global-areal-map account, fMRI orientation decoding relies exclusively on fMRI voxels in V1 exhibiting a radial or vertical preference. Here we show, by contrast, that 2-mm isotropic voxels in a small patch of V1 within a quarterfield representation exhibit reliable opposite selectivities. Sets of voxels with opposite selectivities are locally intermingled and each set can support orientation decoding. This indicates that global areal maps cannot fully account for orientation information in fMRI and demonstrates that fMRI also reflects fine-grained patterns of neuronal selectivity.
A conserved neuronal DAF-16/FoxO plays an important role in conveying pheromone signals to elicit repulsion behavior in Caenorhabditis elegans
Authors: Park Donha , Hahm Jeong-Hoon , Park Saeram , Ha Go , Chang Gyeong-Eon , Jeong Haelim , Kim Heekyeong , Kim Sunhee , Cheong Eunji , Paik Young-Ki
Published: July 2017

Animals use pheromones as a conspecific chemical language to respond appropriately to environmental changes. The soil nematode Caenorhabditis elegans secretes ascaroside pheromones throughout the lifecycle, which influences entry into dauer phase in early larvae, in addition to sexual attraction and aggregation. In adult hermaphrodites, pheromone sensory signals perceived by worms usually elicit repulsion as an initial behavioral signature. However, the molecular mechanisms underlying neuronal pheromone sensory process from perception to repulsion in adult hermaphrodites remain poorly understood. Here, we show that pheromone signals perceived by GPA-3 is conveyed through glutamatergic neurotransmission in which neuronal DAF-16/FoxO plays an important modulatory role by controlling glutaminase gene expression. We further provide evidence that this modulatory role for DAF-16/FoxO seems to be conserved evolutionarily by electro-physiological study in mouse primary hippocampal neurons that are responsible for glutamatergic neurotransmission. These findings provide the basis for understanding the nematode pheromone signaling, which seems crucial for adaptation of adult hermaphrodites to changes in environmental condition for survival.
Development of SimCells as a novel chassis for functional biosensors
Authors: Rampley Cordelia P. N. , Davison Paul A. , Qian Pu , Preston Gail M. , Hunter C. Neil , Thompson Ian P. , Wu Ling Juan , Huang Wei E.
Published: July 2017

This work serves as a proof-of-concept for bacterially derived SimCells (Simple Cells), which contain the cell machinery from bacteria and designed DNA (or potentially a simplified genome) to instruct the cell to carry out novel, specific tasks. SimCells represent a reprogrammable chassis without a native chromosome, which can host designed DNA to perform defined functions. In this paper, the use of Escherichia coli MC1000 ∆minD minicells as a non-reproducing chassis for SimCells was explored, as demonstrated by their ability to act as sensitive biosensors for small molecules. Highly purified minicells derived from E. coli strains containing gene circuits for biosensing were able to transduce the input signals from several small molecules (glucarate, acrylate and arabinose) into the production of green fluorescent protein (GFP). A mathematical model was developed to fit the experimental data for induction of gene expression in SimCells. The intracellular ATP level was shown to be important for SimCell function. A purification and storage protocol was developed to prepare SimCells which could retain their functions for an extended period of time. This study demonstrates that SimCells are able to perform as ‘smart bioparticles’ controlled by designed gene circuits.
Phase transitions in disordered mesoporous solids
Authors: Schneider Daniel , Kondrashova Daria , Valiullin Rustem
Published: July 2017

Fluids confined in mesoporous solids exhibit a wide range of physical behavior including rich phase equilibria. While a notable progress in their understanding has been achieved for fluids in materials with geometrically ordered pore systems, mesoporous solids with complex pore geometries still remain a topic of active research. In this work we study phase transitions occurring in statistically disordered linear chains of pores with different pore sizes. By considering, quite generally, two phase change mechanisms, nucleation and phase growth, occurring simultaneously we obtain the boundary transitions and the scanning curves resulting upon reversing the sign of the evolution of the chemical potential at different points along the main transition branches. The results obtained are found to reproduces the key experimental observations, including the emergence of hysteresis and the scanning behavior. By deriving the serial pore model isotherm we suggest a robust framework for reliable structural analysis of disordered mesoporous solids.
Routes Obey Hierarchy in Complex Networks
Authors: Csoma Attila , Kőrösi Attila , Rétvári Gábor , Heszberger Zalán , Bíró József , Slíz Mariann , Avena-Koenigsberger Andrea , Griffa Alessandra , Hagmann Patric , Gulyás András
Published: July 2017

The last two decades of network science have discovered stunning similarities in the topological characteristics of real life networks (many biological, social, transportation and organizational networks) on a strong empirical basis. However our knowledge about the operational paths used in these networks is very limited, which prohibits the proper understanding of the principles of their functioning. Today, the most widely adopted hypothesis about the structure of the operational paths is the shortest path assumption. Here we present a striking result that the paths in various networks are significantly stretched compared to their shortest counterparts. Stretch distributions are also found to be extremely similar. This phenomenon is empirically confirmed on four networks from diverse areas of life. We also identify the high-level path selection rules nature seems to use when picking its paths.
Phylogenetic relationships among tribes of the green lacewing subfamily Chrysopinae recovered based on mitochondrial phylogenomics
Authors: Jiang Yunlan , Garzón-Orduña Ivonne J. , Winterton Shaun L. , Yang Fan , Liu Xingyue
Published: July 2017

Chrysopidae (green lacewings) is the second largest family in Neuroptera, and it includes medium-size lacewings largely recognized by the presence of golden-colored eyes, bright green bodies and delicate wings with dense venation patterns. The subfamily Chrysopinae includes 97% of the species diversity in the family and it is currently divided into four tribes: Ankylopterygini, Belonopterygini, Chrysopini and Leucochrysini. Here we sequenced and annotated the nearly complete mitochondrial genomes of four species of each these tribes: Abachrysa eureka, Italochrysa insignis, Leucochrysa pretiosa, Parankyloteryx sp. We then reconstructed the phylogenetic relationships with estimated divergence times among tribes of Chrysopinae based on the mt genomic data. Our results suggest that Chrysopinae sans Nothancyla verreauxi evolved as two reciprocally monophyletic lineages formed by stem members of the tribes Leucochrysini plus Belonopterygini on one hand, and the stem members of Ankylopterygini plus Chrysopini on the other. Our estimations of divergence times place the diversification of stem Chrysopinae into the extant tribes during the Middle Jurassic to Late Cretaceous. The relatively young ages previously estimated for the green lacewing divergences were probably underestimated due to false inferences of homology between non-sister taxa that are later correctly identified as homoplasy after more taxa are added.
Disposition and Residue Depletion of Metronidazole in Pigs and Broilers
Authors: Pan Yuanhu , Yi Jiliang , Zhou Bo , Xie Shuyu , Chen Dongmei , Tao Yanfei , Qu Wei , Liu Zhenli , Huang Lingli , Yuan Zonghui
Published: July 2017

Metronidazole (MNZ) is used in veterinary medicine for the treatment of anaerobic infections and a variety of protozoal and parasitic diseases. Current study has been conducted to examine the disposition and residue depletion studies of MNZ and its main metabolites in pigs and broilers. After a single oral administration of MNZ, the concentrations of MNZ and its main metabolites in the excreta of pigs and broilers were determined by LC-MS/MS. More than 75% of the drug was recovered within 14 days, of which MNZ accounted for about 40%, MNZ-OH 20–25% and MAA less than 10%. The residue depletion study showed that MNZ was the most predominant residue in all of the tissues and could be detected in liver, kidney and muscle up to the withdrawal time of 14 days. MNZ-OH concentrations were lower than MNZ in all of the tissues, but its elimination half-life was close to MNZ. It is proposed that kidney and muscle are appropriate residue target tissues and both MNZ and its hydroxylated metabolite, MNZ-OH, should be monitored in the routine surveillance of MNZ related residues in food of animal origin.
Disturbance and mosquito diversity in the lowland tropical rainforest of central Panama
Authors: Loaiza Jose R. , Dutari Larissa C. , Rovira Jose R. , Sanjur Oris I. , Laporta Gabriel Z. , Pecor James , Foley Desmond H. , Eastwood Gillian , Kramer Laura D. , Radtke Meghan , Pongsiri Montira
Published: July 2017

The Intermediate Disturbance Hypothesis (IDH) is well-known in ecology providing an explanation for the role of disturbance in the coexistence of climax and colonist species. Here, we used the IDH as a framework to describe the role of forest disturbance in shaping the mosquito community structure, and to identify the ecological processes that increase the emergence of vector-borne disease. Mosquitoes were collected in central Panama at immature stages along linear transects in colonising, mixed and climax forest habitats, representing different levels of disturbance. Species were identified taxonomically and classified into functional categories (i.e., colonist, climax, disturbance-generalist, and rare). Using the Huisman-Olff-Fresco multi-model selection approach, IDH testing was done. We did not detect a unimodal relationship between species diversity and forest disturbance expected under the IDH; instead diversity peaked in old-growth forests. Habitat complexity and constraints are two mechanisms proposed to explain this alternative postulate. Moreover, colonist mosquito species were more likely to be involved in or capable of pathogen transmission than climax species. Vector species occurrence decreased notably in undisturbed forest settings. Old-growth forest conservation in tropical rainforests is therefore a highly-recommended solution for preventing new outbreaks of arboviral and parasitic diseases in anthropic environments.
A polypeptide from the junction region sequence of EWS-FLI1 inhibits Ewing’s sarcoma cells, interacts with the EWS-FLI1 and partner proteins
Authors: Thangaretnam Krishna Priya , Gopisetty Gopal , Ramanathan Priya , Rajkumar Thangarajan
Published: July 2017

The EWS-FLI1 chimeric protein uniquely expressed in Ewing’s sarcoma has an obligate role in its aetiology. In our previous report we showed that ectopic expression of the DNA sequences form the junction region (a.a 251–280) can inhibit Ewing’s sarcoma cell growth. In the present report, we introduced a peptide (TAT/NLS/EWS-PEP) comprising of thirty amino acids spanning the junction in conjunction with HIV-1-trans-activating (TAT) and nuclear localization signal sequence (NLS). Peptide uptake and localization studies revealed presence of peptide in ~99% of transduced cells and in the nucleus. Peptide transfection induced cytotoxicity relative to untreated and TAT-NLS peptide treated Ewing’s sarcoma cells. The peptide inhibited clonogenicity, cell cycle, bromo-deoxy uridine (BrdU) uptake and invasion capacity of treated cells. The treatment also affected epithelial to mesenchymal transition (EMT) markers and EWS-FLI1 target gene expression levels. Co-immunoprecipitation experiments involving ectopically expressed full-length EWS-FLI1 protein and the peptide revealed an interaction. Additionally, we found that peptide interaction also occurs with the protein-GGAA microsatellite sequences complex known to contain EWS-FLI1. Further, in the pull-down assay, the peptide was found to interact with proteins known to potentially interact with EWS-FLI1. Based on these results we conclude that peptide could be applied in targeting EWS-FLI1 protein.
Ndrg1 promotes adipocyte differentiation and sustains their function
Authors: Cai Kai , El-Merahbi Rabih , Loeffler Mona , Mayer Alexander E. , Sumara Grzegorz
Published: July 2017

Adipocytes play a central role in maintaining metabolic homeostasis in the body. Differentiation of adipocyte precursor cells requires the transcriptional activity of peroxisome proliferator-activated receptor-γ (Pparγ) and CCAAT/enhancer binding proteins (C/Ebps). Transcriptional activity is regulated by signaling modules activated by a plethora of hormones and nutrients. Mechanistic target of rapamacin complexes (mTORC) 1 and 2 are central for the coordination of hormonal and nutritional inputs in cells and are essential for adipogenesis. Serum glucocorticoid kinase 1 (Sgk1)-dependent phosphorylation of N-Myc downstream-regulated gene 1 (Ndrg1) is a hallmark of mTORC2 activation in cells. Moreover, Pparγ activation promotes Ndrg1 expression. However, the impact of Ndrg1 on adipocyte differentiation and function has not yet been defined. Here, we show that Ndrg1 expression and its Sgk1-dependent phosphorylation are induced during adipogenesis. Consistently, we demonstrate that Ndrg1 promotes adipocyte differentiation and function by inducing Pparγ expression. Additionally, our results indicate that Ndrg1 is required for C/Ebpα phosphorylation. Moreover, we found that Ndrg1 phosphorylation by Sgk1 promotes adipocyte formation. Taken together, we show that induction of Ndrg1 expression by Pparγ and its phosphorylation by Sgk1 kinase are required for the acquisition of adipocyte characteristics by precursor cells.
Calcium and vitamin-D deficiency marginally impairs fracture healing but aggravates posttraumatic bone loss in osteoporotic mice
Authors: Fischer Verena , Haffner-Luntzer Melanie , Prystaz Katja , vom Scheidt Annika , Busse Björn , Schinke Thorsten , Amling Michael , Ignatius Anita
Published: July 2017

Calcium and vitamin-D (Ca/VitD) deficiency is a major risk factor for osteoporosis. It may also contribute to the compromised bone healing frequently observed in osteoporotic patients, since calcium is essential for fracture-callus mineralization. Additionally, clinical data suggest systemic bone loss following fracture, which may aggravate osteoporosis and thus increase the risk for fragility fractures in osteoporotic patients further. However, the role of Ca/VitD in fracture healing and posttraumatic bone turnover has to date been poorly investigated. Here, we studied bone regeneration and posttraumatic bone turnover in C57BL/6 J mice with ovariectomy-induced osteoporosis. Mice were fed a standard or a Ca/VitD-deficient diet. Notably, fracture healing was only marginally disturbed in Ca/VitD-deficient mice. However, deficient mice displayed significantly increased serum parathyroid hormone levels and osteoclast activity, as well as reduced bone mass in the intact skeleton post-fracture, suggesting considerably enhanced calcium mobilization from the intact skeleton during bone regeneration. Ca/VitD supplementation initiated post-fracture prevented posttraumatic bone loss by reducing bone resorption and furthermore improved bone repair. These results imply that adequate Ca/VitD supply post-fracture is essential to provide sufficient calcium for callus-mineralization in order to prevent posttraumatic bone loss and to reduce the risk for secondary fractures in osteoporotic patients with Ca/VitD deficiency.
Neural substrates of embodied natural beauty and social endowed beauty: An fMRI study
Authors: Zhang Wei , He Xianyou , Lai Siyan , Wan Juan , Lai Shuxian , Zhao Xueru , Li Darong
Published: July 2017

What are the neural mechanisms underlying beauty based on objective parameters and beauty based on subjective social construction? This study scanned participants with fMRI while they performed aesthetic judgments on concrete pictographs and abstract oracle bone scripts. Behavioral results showed both pictographs and oracle bone scripts were judged to be more beautiful when they referred to beautiful objects and positive social meanings, respectively. Imaging results revealed regions associated with perceptual, cognitive, emotional and reward processing were commonly activated both in beautiful judgments of pictographs and oracle bone scripts. Moreover, stronger activations of orbitofrontal cortex (OFC) and motor-related areas were found in beautiful judgments of pictographs, whereas beautiful judgments of oracle bone scripts were associated with putamen activity, implying stronger aesthetic experience and embodied approaching for beauty were elicited by the pictographs. In contrast, only visual processing areas were activated in the judgments of ugly pictographs and negative oracle bone scripts. Results provide evidence that the sense of beauty is triggered by two processes: one based on the objective parameters of stimuli (embodied natural beauty) and the other based on the subjective social construction (social endowed beauty).
Temporally Robust Eye Movements through Task Priming and Self-referential Stimuli
Authors: Jung Eun-Soo , Lee Dong-Gun , Lee Kyeongho , Lee Soo-Young
Published: July 2017

Studies have demonstrated connections between eye movements and attention shifts. However, little is known about the general factors that contribute to the self-consistency of idiosyncratic scanpaths as a function of attention shifts over time. The present work repeatedly measured human eye movements at various time intervals that ranged from less than one hour to one year between recording sessions. With and without task context, subjects observed multiple images with multiple areas of interest, including their own sporadically interspersed facial images. As reactions to visual stimuli, the eye movements of individuals were compared within and between subjects. We compared scanpaths with dynamic time warping and identified subjects based on the comparisons. The results indicate that within-subject eye movement comparisons remain more similar than between-subject eye movement comparisons over time and that task context and self-referential stimuli contribute to the consistency of idiosyncrasies in attention shift patterns.
Rapid de novo assembly of the European eel genome from nanopore sequencing reads
Authors: Jansen Hans J. , Liem Michael , Jong-Raadsen Susanne A. , Dufour Sylvie , Weltzien Finn-Arne , Swinkels William , Koelewijn Alex , Palstra Arjan P. , Pelster Bernd , Spaink Herman P. , Thillart Guido E. van den , Dirks Ron P. , Henkel Christiaan V.
Published: July 2017

We have sequenced the genome of the endangered European eel using the MinION by Oxford Nanopore, and assembled these data using a novel algorithm specifically designed for large eukaryotic genomes. For this 860 Mbp genome, the entire computational process takes two days on a single CPU. The resulting genome assembly significantly improves on a previous draft based on short reads only, both in terms of contiguity (N50 1.2 Mbp) and structural quality. This combination of affordable nanopore sequencing and light weight assembly promises to make high-quality genomic resources accessible for many non-model plants and animals.