bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial Distribution of Io's Neutral Oxygen Cloud Observed by Hisaki
Authors: Koga Ryoichi , Tsuchiya Fuminori , Kagitani Masato , Sakanoi Takeshi , Yoneda Mizuki , Yoshioka Kazuo , Yoshikawa Ichiro , Kimura Tomoki , Murakami Go , Yamazaki Atsushi , Smith H. Todd , Bagenal Fran
Published: April 2018

We report on the spatial distribution of a neutral oxygen cloud surrounding Jupiter's moon Io and along Io's orbit observed by the Hisaki satellite. Atomic oxygen and sulfur in Io's atmosphere escape from the exosphere mainly through atmospheric sputtering. Some of the neutral atoms escape from Io's gravitational sphere and form neutral clouds around Jupiter. The extreme ultraviolet spectrograph called EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) installed on the Japan Aerospace Exploration Agency's Hisaki satellite observed the Io plasma torus continuously in 2014–2015, and we derived the spatial distribution of atomic oxygen emissions at 130.4 nm. The results show that Io's oxygen cloud is composed of two regions, namely, a dense region near Io and a diffuse region with a longitudinally homogeneous distribution along Io's orbit. The dense region mainly extends on the leading side of Io and inside of Io's orbit. The emissions spread out to 7.6 Jupiter radii (RJ). Based on Hisaki observations, we estimated the radial distribution of the atomic oxygen number density and oxygen ion source rate. The peak atomic oxygen number density is 80 cm−3, which is spread 1.2 RJ in the north‐south direction. We found more oxygen atoms inside Io's orbit than a previous study. We estimated the total oxygen ion source rate to be 410 kg/s, which is consistent with the value derived from a previous study that used a physical chemistry model based on Hisaki observations of ultraviolet emission ions in the Io plasma torus.
Publisher Correction: Chloroquine modulates antitumor immune response by resetting tumor-associated macrophages toward M1 phenotype
Authors: Chen Degao , Xie Jing , Fiskesund Roland , Dong Wenqian , Liang Xiaoyu , Lv Jiadi , Jin Xun , Liu Jinyan , Mo Siqi , Zhang Tianzhen , Cheng Feiran , Zhou Yabo , Zhang Huafeng , Tang Ke , Ma Jingwei , Liu Yuying , Huang Bo
Published: April 2018

In the originally published version of this Article, images in Fig. 5n were inadvertently replaced with duplicates of images in Fig. 5o during the production process. This has now been corrected in both the PDF and HTML versions of the Article.
Flutter to tumble transition of buoyant spheres triggered by rotational inertia changes
Authors: Mathai Varghese , Zhu Xiaojue , Sun Chao , Lohse Detlef
Published: April 2018

Heavy particles sink straight in water, while buoyant bubbles and spheres may zigzag or spiral as they rise. The precise conditions that trigger such path-instabilities are still not completely understood. For a buoyant rising sphere, two parameters are believed to govern the development of unsteady dynamics: the particle’s density relative to the fluid, and its Galileo number. Consequently, with these parameters specified, the opportunities for variation in particle dynamics appear limited. In contrast to this picture, here we demonstrate that vigorous path-oscillations can be triggered by modulating a spherical particle’s moment of inertia (MoI). For a buoyant sphere rising in a turbulent flow, MoI reduction triggers a tumble–flutter transition, while in quiescent liquid, it induces a modification of the sphere wake resulting in large-amplitude path-oscillations. The present finding opens the door for control of particle path- and wake-instabilities, with potential for enhanced mixing and heat transfer in particle-laden and dispersed multiphase environments.
Publisher Correction: Small-angle neutron scattering modeling of spin disorder in nanoparticles
Authors: Vivas Laura G. , Yanes Rocio , Michels Andreas
Published: April 2018

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
PKC Dependent p14ARF Phosphorylation on Threonine 8 Drives Cell Proliferation
Authors: Fontana Rosa , Guidone Daniela , Sangermano Felicia , Calabrò Viola , Pollice Alessandra , La Mantia Girolama , Vivo Maria
Published: April 2018

ARF role as tumor suppressor has been challenged in the last years by several findings of different groups ultimately showing that its functions can be strictly context dependent. We previously showed that ARF loss in HeLa cells induces spreading defects, evident as rounded morphology of depleted cells, accompanied by a decrease of phosphorylated Focal Adhesion Kinase (FAK) protein levels and anoikis. These data, together with previous finding that a PKC dependent signalling pathway can lead to ARF stabilization, led us to the hypothesis that ARF functions in cell proliferation might be regulated by phosphorylation. In line with this, we show here that upon spreading ARF is induced through PKC activation. A constitutive-phosphorylated ARF mutant on the conserved threonine 8 (T8D) is able to mediate both cell spreading and FAK activation. Finally, ARF-T8D expression confers growth advantage to cells thus leading to the intriguing hypothesis that ARF phosphorylation could be a mechanism through which pro-proliferative or anti proliferative signals could be transduced inside the cells in both physiological and pathological conditions.
Basalt fibers coated with nano-calcium carbonate for in-tube solid-phase microextraction and online analysis of estrogens coupled with high-performance liquid chromatography
Authors: Wang Xiuqin , Feng Juanjuan , Feng Jiaqing , Tian Yu , Luo Chuannan , Sun Min
Published: April 2018

Estrogens have caused many serious problems due to their serious effects on the environment and organisms.
Natural and synthetic avenanthramides activate caspases 2, 8, 3 and downregulate hTERT, MDR1 and COX-2 genes in CaCo-2 and Hep3B cancer cells
Authors: Scarpa E. S. , Mari M. , Antonini E. , Palma F. , Ninfali P.
Published: April 2018

Avenanthramides inhibit proliferation of CaCo-2 and Hep3B cancer cells through induction of apoptosis and downregulation of pro-survival mechanisms.
A novel EI-GC/MS method for the accurate quantification of anti-aging compound oleoylethanolamine inC. elegans
Authors: Annibal Andrea , Karalay Özlem , Latza Christian , Antebi Adam
Published: April 2018

A novel GC-MS method for the quantification of oleoylethanolamine inC. elegans.
Cascade dehydrative amination of glycerol to oxazoline
Authors: Pandya R. , Mane R. , Rode C. V.
Published: April 2018

A method for the direct conversion of bioglycerol to oxazoline was devised involving glycerol dehydration to acetol followed by its amination with aqueous ammonia.
In situfield trial to evaluate the efficacy of Cutrine Ultra to manage a cyanobacteria population in a drinking water source
Authors: Crafton Elizabeth A. , Glowczewski Jessica , Ott Donald W. , Cutright Teresa J.
Published: April 2018

Research found that a 1/4 dose of the manufacturer's recommended application amount could mitigate HABs over short periods of time.
Healing surface roughness of lithographic nanopatterns through sub-10 nm aqueous-dispersible polymeric particles with excellent dry etch durability
Authors: Jiang Zhen , Cheng Han-Hao , Blakey Idriss , Whittaker Andrew K.
Published: April 2018

Herein we demonstrate the design and use of sub-10 nm etch-durable polymeric particles for healing roughness in lithographic patterns.
MXP(M = Co/Ni)@carbon core–shell nanoparticles embedded in 3D cross-linked graphene aerogel derived from seaweed biomass for hydrogen evolution reaction
Authors: Zhao Wentong , Lu Xiaoqing , Selvaraj Manickam , Wei Wei , Jiang Zhifeng , Ullah Nabi , Liu Jie , Xie Jimin
Published: April 2018

Low-cost electrocatalysts play an important role in the hydrogen evolution reaction (HER).
Correction: A novel nanomissile targeting two biomarkers and accurately bombing CTCs with doxorubicin
Authors: Gao Yu , Xie Xiaodong , Li Fengqiao , Lu Yusheng , Li Tao , Lian Shu , Zhang Yingying , Zhang Huijuan , Mei Hao , Jia Lee
Published: April 2018

Correction for ‘A novel nanomissile targeting two biomarkers and accurately bombing CTCs with doxorubicin’ by Yu Gao et al., Nanoscale, 2017, 9, 5624–5640.
Rationally designed hyperbranched azopolymer with temperature, photo and pH responsive behavior
Authors: Sun Liuying , Gao Fei , Shen Dingfeng , Liu Zhenghui , Yao Yuan , Lin Shaoliang
Published: April 2018

A novel hyperbranched azopolymer, HPAzoAMAM-star-EG3, was synthesized and it could self-assemble into uniform large compound micelles with multi-stimuli responsive behavior.
Frontiers of Macromolecular and Supramolecular Science symposia
Authors: Klein Michael L. , Percec Virgil
Published: April 2018

Michael L. Klein and Virgil Percec introduce this Polymer Chemistry themed collection containing a selection of publications contributed by lecturers from the Frontiers of Macromolecular and Supramolecular Science symposia and friends of Christofor I. Simionescu.
Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity
Authors: Pump Eva , Bendjeriou-Sedjerari Anissa , Viger-Gravel Jasmine , Gajan David , Scotto Baptiste , Samantaray Manoja K. , Abou-Hamad Edy , Gurinov Andrei , Almaksoud Walid , Cao Zhen , Lesage Anne , Cavallo Luigi , Emsley Lyndon , Basset Jean-Marie
Published: April 2018

Identification of surfaces at the molecular level has benefited from progress in dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP SENS).
Cu-catalyzed enantioselective synthesis of tertiary benzylic copper complexes and their in situ addition to carbonyl compounds
Authors: Cheng Fengchang , Lu Wenxin , Huang Wei , Wen Lu , Li Mingfeng , Meng Fanke
Published: April 2018

Catalytic chemo- and enantioselective generation of tertiary benzylic copper complexes from Cu–B(pin) (pin = pinacolato) additions to 1,1-disubstituted alkenes followed by in situ reactions with ketones and carboxylic acid phenol esters to construct multifunctional alkylboron compounds that contain quaternary stereogenic centers is presented.
Design of efficient bifunctional catalysts for direct conversion of syngas into lower olefinsviamethanol/dimethyl ether intermediates
Authors: Liu Xiaoliang , Zhou Wei , Yang Yudan , Cheng Kang , Kang Jincan , Zhang Lei , Zhang Guoquan , Min Xiaojian , Zhang Qinghong , Wang Ye
Published: April 2018

Zn–ZrO2/SSZ-13 catalyzed direct conversion of syngas into lower olefinsviamethanol/DME intermediates with 77% selectivity at 29% CO conversion.
Seasonal variation of biochemical composition of Noah's ark shells (Arca noaeL. 1758) in a Tunisian coastal lagoon in relation to its reproductive cycle and environmental conditions
Authors: Ghribi Feriel , Boussoufa Dhouha , Aouini Fatma , Bejaoui Safa , Chetoui Imene , Rabeh Imen , El Cafsi M'hamed
Published: April 2018

The seasonal changes in biochemical composition of the edible bivalveArca noaeharvested from a Mediterranean coastal lagoon (Bizerte lagoon, Tunisia) were investigated from October 2013 to September 2014. Potential food sources and nutritional quality indices (NQI) were determined by analyzing the fatty acid profiles of their tissues during an annual reproductive cycle. Results showed thatA. noaehad moisture (73.8–82%) and protein (24.1–58.6% dry weight) as major components, followed by lipid (10.4–28.8% dry weight) and glycogen (4.05–14.6% dry weight).A. noaeaccumulated lipid and glycogen for gonadal development during both maturation periods (late autumn/late spring–summer) to be used during spawning periods (winter/late summer–early autumn). However, proteins were mainly used to support reproductive allocation and played an important role on the energetic maintenance. Lipid and glycogen were found to be significantly related to temperature, salinity and chlorophylla(p < 0.05). An increase of condition index (CI) was observed during spring and early summer when both temperature and food supply increased. The total fatty acid (TFA) profile of Ark shells was dominated by polyunsaturated fatty acids (PUFA) (33.8–49.6%), followed by saturated (SFA) (29.1–43.1%) and monounsaturated fatty acids (MUFA) (20.77–28.3%).A. noaesoft tissues were also rich in macro-minerals (Na, Ca and Mg). The analysis of fatty acid trophic markers revealed that the diet ofA. noaeduring the year of study was based on mixture food mainly on phytoplankton followed by zooplankton and other sources (bacteria, seagrass and macroalgae). Furthermore, the nutritional quality indices have revealed thatA. noaeis an excellent source of nutrients and a healthy food for human consumption. These data are useful to the conservation of natural stocks ofA. noaeand the development of sustainable aquaculture production of this shellfish species in the Bizerte lagoon.
Versatile mid-infrared frequency-comb referenced sub-Doppler spectrometer
Authors: Gambetta A. , Vicentini E. , Coluccelli N. , Wang Y. , Fernandez T. T. , Maddaloni P. , De Natale P. , Castrillo A. , Gianfrani L. , Laporta P. , Galzerano G.
Published: April 2018

We present a mid-IR high-precision spectrometer capable of performing accurate Doppler-free measurements with absolute calibration of the optical axis and high signal-to-noise ratio. The system is based on a widely tunable mid-IR offset-free frequency comb and a Quantum-Cascade-Laser (QCL). The QCL emission frequency is offset locked to one of the comb teeth to provide absolute-frequency calibration, spectral-narrowing, and accurate fine frequency tuning. Both the comb repetition frequency and QCL-comb offset frequency can be modulated to provide, respectively, slow- and fast-frequency-calibrated scanning capabilities. The characterisation of the spectrometer is demonstrated by recording sub-Doppler saturated absorption features of the CHF3 molecule at around 8.6 μm with a maximum signal-to-noise ratio of ∼7 × 103 in 10 s integration time, frequency-resolution of 160 kHz, and accuracy of less than 10 kHz.
High doping effect on the thermoelectric properties of p-type lead telluride
Authors: Dmitriev A. V.
Published: April 2018

We study theoretically the effect of heavy doping on the thermoelectric properties of p-type PbTe in the acceptor doping interval of 5 × 1019 to 4 × 1020 cm−3 and in the temperature range of 300 to 900 K. In our calculations, a three-band model of the PbTe electron energy spectrum is used that takes into account not only the light electron and hole bands but also the heavy-hole band. This so-called Σ-band plays an important role in the emergence of the figure-of-merit increase in this material at heavy acceptor doping. The calculated thermoelectric characteristics appear to be sensitive to the doping level. An increase in the figure-of-merit up to ZT ≈ 1.3 at 900 K was found at the doping level of 2 × 1020 cm−3. The maximum of ZT on the temperature axis is situated close to the temperature at which the light hole and heavy hole band edges coincide and hence, a prominent density-of-states singularity appears in the valence band, and the Fermi level lies near this singularity.
Strain-induced oriented crystallization of UHMWPE: Enhanced thermal conductivity through molecular chain alignment
Authors: Guo Yanting , Leung Siu N.
Published: April 2018

Thermal conductivity of bulk polymers can be enhanced by strain-induced oriented crystallization. This work reports a three-step solution-free fabrication process to promote a polymer film’s molecular chain alignment. First, the mobility of molecular chain is promoted by equilibrating the film at an elevated temperature. Second, the film is mechanically drawn at controlled strain level, strain rate, and temperature. Third, the stretched film is rapidly cooled to stabilize its microstructure. Parametric studies have identified that promoting intermolecular fringed-micelles with preferential orientation without unfolding the intramolecular folded-chain nucleus can maximize its in-plane thermal conductivity.
Reflections on a seminal paper in conservation biology: the legacy of Peters and Darling (1985)
Authors: Hughes Lesley
Published: April 2018

‘The Greenhouse Effect and Nature Reserves’ by Robert Peters and Joan Darling, published in the journal Bioscience more than 30 years ago, was a ground-breaking synthesis. Drawing on paleoecology, community ecology and biogeography, the review laid out many concepts about species vulnerability to climate change that have become central tenets of research on climate change adaptation in natural ecosystems. Remarkably, the paper also provided a clear and logical framework for flexible, forward-thinking and interventionist management action, including recommendations about the design of protected areas, and the need for species translocation to reduce extinction risk. Reflecting on the legacy of this paper, it is clear that the uptake of such approaches over the intervening decades has been extremely slow, representing many lost opportunities to reduce species vulnerability to rapid environmental change. This paper is a tribute to the prescience of Peters and Darling, and a call to revisit their farsighted advice to meet conservation challenges that continue to accelerate.
Tunneling explains efficient electron transport via protein junctions
Authors: Fereiro Jerry A. , Yu Xi , Pecht Israel , Sheves Mordechai , Cuevas Juan Carlos , Cahen David
Published: April 2018

Significance

Investigation of the charge transport mechanism across a monolayer of a redox active protein is important for the fundamental understanding of the naturally occurring electron transfer processes, such as those in photosynthesis or respiration. Inelastic electron tunneling spectroscopy measurements of a redox active protein may provide direct experimental evidence that the tunneling charges are, in fact, passing through the protein molecules. Results of our study of conductance via well-controlled azurin monolayer solid-state junctions show the direct involvement of the Cu(II) site in assisting electron transport, underscoring this site’s vibronic characteristics associated with the charge transport mechanism. Our study widens the scope of currently available methodologies and also adds to the potential of using proteins in bioelectronics.
Symbiont switching and alternative resource acquisition strategies drive mutualism breakdown
Authors: Werner Gijsbert D. A. , Cornelissen Johannes H. C. , Cornwell William K. , Soudzilovskaia Nadejda A. , Kattge Jens , West Stuart A. , Kiers E. Toby
Published: April 2018

Significance

Cooperative interactions among species—mutualisms—are major sources of evolutionary innovation. However, despite their importance, two species that formerly cooperated sometimes cease their partnership. Why do mutualisms break down? We asked this question in the partnership between arbuscular mycorrhizal (AM) fungi and their plant hosts, one of the most ancient mutualisms. We analyze two potential trajectories toward evolutionary breakdown of their cooperation, symbiont switching and mutualism abandonment. We find evidence that plants stop interacting with AM fungi when they switch to other microbial mutualists or when they evolve alternative strategies to extract nutrients from the environment. Our results show vital cooperative interactions can be lost, but only if successful alternatives evolve.
Structural homo- and heterosynaptic plasticity in mature and adult newborn rat hippocampal granule cells
Authors: Jungenitz Tassilo , Beining Marcel , Radic Tijana , Deller Thomas , Cuntz Hermann , Jedlicka Peter , Schwarzacher Stephan W.
Published: April 2018

Significance

The lifelong genesis of hippocampal granule cells (abGCs) enables specific forms of spatial learning. We analyzed which forms of synaptic plasticity are present in abGCs in comparison with mature granule cells (mGCs). We found structural equivalents of homosynaptic long-term potentiation and heterosynaptic long-term depression, two fundamental forms of cellular learning. abGCs and mGCs showed spine enlargement on stimulated segments and spine shrinkage on nonstimulated segments concurrently present on dendrites of individual cells, indicating a sharpening and a homeostatic regulation of synaptic efficacy. abGCs expressed homo- and heterosynaptic spine plasticity with a clear onset between 4–5 wk of cell age, demonstrating increasing synaptic plasticity during the phase of abGC integration on the structural level.
High-order fractal states in graphene superlattices
Authors: Krishna Kumar R. , Mishchenko A. , Chen X. , Pezzini S. , Auton G. H. , Ponomarenko L. A. , Zeitler U. , Eaves L. , Fal’ko V. I. , Geim A. K.
Published: April 2018

Significance

Electronic spectra of crystals in ultrahigh magnetic fields are expected to be fractal as symbolized by the theoretical plots called Hofstadter butterflies. Despite decades-long interest, their origin is often misconstrued. In fact, the fractal spectra can be understood as recurrence of delocalized Bloch states that appear each time the magnetic length becomes commensurate with the lattice periodicity. In this case, new quasiparticles emerge, moving through the crystal as if no magnetic field is applied. Their Landau quantization in noncommensurate fields generates the whole intricacy of Hofstadter spectra. Here, we study electron transport in graphene superlattices and report numerous self-similar features in their conductivity. This is a direct observation of the complete fractal pattern that underpins Hofstadter butterflies.
Recipe Names as a Gateway to Interpersonal Communication
Authors: Tsujimura Natsuko
Published: April 2018

An examination of Japanese cookbooks from the early twentieth century to date demonstrates that changes in the nature of recipe names over the past 87 years have made the relationship between the writer and the audience closer. Recipe names have come to be more informative and creative through the rich use of mimetics, metaphors, and word play. Furthermore, they have become more personalized and stylized. The personal stories behind these recipe names help the author elicit in readers a sense of camaraderie and/or nostalgic memories that specific food items in a given historical period evoke. This article demonstrates two things: what seem to be simple names for recipes can be regarded as a gateway to interpersonal communication between the author and audience; and recipe names have evolved into an increasingly enriched form of communication over time by ingenious use of various tools available in the language.
Quasimodularity and large genus limits of Siegel-Veech constants
Authors: Chen Dawei , Möller Martin , Zagier Don
Published: April 2018

Quasimodular forms were first studied systematically in the context of counting torus coverings. Here we show that a weighted version of these coverings with Siegel-Veech weights also provides quasimodular forms. We apply this to prove conjectures of Eskin and Zorich on the large genus limits of Masur-Veech volumes and of Siegel-Veech constants.

In Part I we connect the geometric definition of Siegel-Veech constants both with a combinatorial counting problem and with intersection numbers on Hurwitz spaces. We also introduce certain modified Siegel-Veech weights whose generating functions will later be shown to be quasimodular.

Parts II and III are devoted to the study of the (quasi) modular properties of the generating functions arising from weighted counting of torus coverings. These two parts contain little geometry and can be read independently of the rest of the paper. The starting point is the theorem of Bloch and Okounkov saying that certain weighted averages, called

q
q

-brackets, of shifted symmetric functions on partitions are quasimodular forms. In Part II we give an expression for the growth polynomials (a certain polynomial invariant of quasimodular forms) of these

q
q

-brackets in terms of Gaussian integrals, and we use this to obtain a closed formula for the generating series of cumulants that is the basis for studying large genus asymptotics. In Part III we show that the even hook-length moments of partitions are shifted symmetric polynomials, and we prove a surprising formula for the

q
q

-bracket of the product of such a hook-length moment with an arbitrary shifted symmetric polynomial as a linear combination of derivatives of Eisenstein series. This formula gives a quasimodularity statement also for the

(
−
2
)

(-2)

-nd hook-length moments by an appropriate extrapolation, and this in turn implies the quasimodularity of the Siegel-Veech weighted counting functions.

Finally, in Part IV these results are used to give explicit generating functions for the volumes and Siegel-Veech constants in the case of the principal stratum of abelian differentials. The generating functions have an amusing form in terms of the inversion of a power series (with multiples of Bernoulli numbers as coefficients) that gives the asymptotic expansion of a Hurwitz zeta function. To apply these exact formulas to the Eskin-Zorich conjectures on large genus asymptotics (both for the volume and the Siegel-Veech constant) we provide in a separate appendix a general framework for computing the asymptotics of rapidly divergent power series.
Quasi–Monte Carlo integration with product weights for elliptic PDEs with log-normal coefficients
Authors: Kazashi Yoshihito
Published: April 2018

Quasi–Monte Carlo (QMC) integration of output functionals of solutions of the diffusion problem with a log-normal random coefficient is considered. The random coefficient is assumed to be given by an exponential of a Gaussian random field that is represented by a series expansion of some system of functions. Graham et al. (2015, Quasi-Monte Carlo finite element methods for elliptic PDEs with lognormal random coefficients. Numer. Math., 131, 329–368) developed a lattice-based QMC theory for this problem and established a quadrature error decay rate ≈ 1 with respect to the number of quadrature points. The key assumption there was a suitable summability condition on the aforementioned system of functions. As a consequence, product-order-dependent weights were used to construct the lattice rule. In this paper, a different assumption on the system is considered. This assumption, originally considered by Bachmayr et al. (2017c, Sparse polynomial approximation of parametric elliptic PDEs. Part I: affine coefficients. ESAIM Math. Model. Numer. Anal., 51, 321–339) to utilise the locality of support of basis functions in the context of polynomial approximations applied to the same type of the diffusion problem, is shown to work well in the same lattice-based QMC method considered by Graham et al.: the assumption leads us to product weights, which enables the construction of the QMC method with a smaller computational cost than Graham et al. A quadrature error decay rate ≈ 1 is established, and the theory developed here is applied to a wavelet stochastic model. By a characterisation of the Besov smoothness, it is shown that a wide class of path smoothness can be treated with this framework.
Identification and period investigation of pulsation variable star UY Camelopardalis, an RR Lyrae star in binary system
Authors: Li Lin-Jia , Qian Sheng-Bang , Voloshina Irina , Metlov Vladimir G , Zhu Li-Ying , Liao Wen-Ping
Published: April 2018

We present photometric measurements of the short period variable star UY Cam, which has been classified as a δ Scuti or c-type RR Lyrae (RRc) variable in different catalogs. Based on the analyses on Fourier coefficients and (NUV − V)0, we find that UY Cam is probably an RRc star. We obtain 58 new times of light maximum for UY Cam based on several sky surveys and our observations. Combining these with the times of light maximum in literature, a total of 154 times of light maximum are used to analyze the O − C diagram of UY Cam. The results show that the O − C pattern can be described by a downward parabolic component with a rate of −6.86 ± 0.47 × 10−11 d d−1, and a cyclic variation with a period of 65.7 ± 2.4 yr. We suppose these components are caused by the stellar evolution and the light travel time effect (LiTE) of a companion in elliptical orbit, respectively. By calculation, the minimum mass of the potential companion is about 0.17 M⊙, and its mass should be less than or equal to the pulsation primary star when the inclination $i > {22{^{\circ}_{.}}5}$. Therefore, the companion should be a low-mass star, like a late-type main-sequence star or a white dwarf. Due to the unique property of UY Cam, we suggest that more observations and studies on UY Cam and other RRc stars are needed to check the nature of these stars, including the pulsations and binarities.
Genomic, Proteomic and Phenotypic Heterogeneity in HeLa Cells across Laboratories: Implications for Reproducibility of Research Results
Authors: Liu Yansheng , Mi Yang , Mueller Torsten , Kreibich Saskia , Williams Evan G. , Van Drogen Audrey , Borel Christelle , Germain Pierre-Luc , Frank Max , Bludau Isabell , Mehnert Martin , Seifert Michael , Emmenlauer Mario , Sorg Isabel , Bezrukov Fedor , Sloan Bena Frederique , Zhou Hu , Dehio Christoph , Testa Giuseppe , Saez-Rodriguez Julio , Antonarakis Stylianos E. , Hardt Wolf-Dietrich , Aebersold Ruedi
Published: April 2018

The independent reproduction of research results is a cornerstone of experimental research, yet it is beset by numerous challenges, including the quality and veracity of reagents and materials. Much of life science research depends on life materials, including human tissue culture cells. In this study we aimed at determining the degree of variability in the molecular makeup and the ensuing phenotypic consequences in commonly used human tissue culture cells. We collected 14 stock HeLa aliquots from 13 different laboratories across the globe, cultured them in uniform conditions and profiled the genome-wide copy numbers, mRNAs, proteins and protein turnover rates via genomic techniques and SWATH mass spectrometry, respectively. We also phenotyped each cell line with respect to the ability of transfected Let7 mimics to modulate Salmonella infection.

We discovered significant heterogeneity between HeLa variants, especially between lines of the CCL2 and Kyoto variety. We also observed progressive divergence within a specific cell line over 50 successive passages. From the aggregate multi-omic datasets we quantified the response of the cells to genomic variability across the transcriptome and proteome. We discovered organelle-specific proteome remodeling and buffering of protein abundance by protein complex stoichiometry, mediated by the adaptation of protein turnover rates. By associating quantitative proteotype and phenotype measurements we identified protein patterns that explained the varying response of the different cell lines to Salmonella infection.

Altogether the results indicate a striking degree of genomic variability, the rapid evolution of genomic variability in culture and its complex translation into distinctive expressed molecular and phenotypic patterns. The results have broad implications for the interpretation and reproducibility of research results obtained from HeLa cells and provide important basis for a general discussion of the value and requirements for communicating research results obtained from human tissue culture cells.
A cell separation checkpoint that enforces the proper order of late cytokinetic events
Authors: Brace Jennifer L. , Doerfler Matthew D. , Weiss Eric L.
Published: April 2018

Eukaryotic cell division requires sequence dependency relationships in which late processes commence only after early ones are appropriately completed. We have discovered a system that blocks late events of cytokinesis until early ones are successfully accomplished. In budding yeast, cytokinetic actomyosin ring contraction and membrane ingression are coupled with deposition of an extracellular septum that is destroyed immediately after its completion by secreted enzymes. We find this secretion event is linked to septum completion and forestalled when the process is slowed. Delay of septum destruction requires Fir1, an intrinsically disordered protein localized to the cytokinesis site that is degraded upon septum completion but stabilized when septation is aberrant. Fir1 appears to protect cytokinesis in part by inhibiting a separation-specific exocytosis function of the NDR/LATS kinase Cbk1, a key component of a “hippo” signaling pathway that induces mother-daughter separation. We term this system “enforcement of cytokinesis order” (ECO), a checkpoint ensuring proper temporal sequence of mechanistically incompatible processes of cytokinesis.
M1A within cytoplasmic mRNAs at single nucleotide resolution: A reconciled transcriptome-wide map
Authors: Schwartz Schraga
Published: April 2018

Following synthesis, RNA can be modified with over 100 chemically distinct modifications, and in recent years it was shown that processing, localization, stability and translation of mRNAs can be impacted by an increasing number of these modifications. A modification that recently gained attention is N1-methyladenosine (m1A), which is present across all three domains of life. Recently, two studies - one of them ours - developed conceptually similar approaches to map m1A in a transcriptome-wide manner and at single nucleotide resolution. Surprisingly, the two studies diverged quite substantially in terms of their estimates of the abundance, whereabouts and stoichiometry of this modification within internal sites in cytosolic mRNAs: One study reported it to be a very rare modification, present at very low stoichiometries, and invariably catalyzed by TRMT6/61A. The other found it to be present at >470 sites, in dozens of which at relatively high levels, and in the vast majority of cases these sites were highly unlikely to be substrates of TRMT6/61A, suggesting that additional methyltransferases are active on cytosolic mRNAs. Here we aim to reconcile the contradictions between the two studies, primarily by reanalyzing and re-annotating the set of sites identified in the latter study. We find that the vast majority of sites detected in this study originate from duplications, misannotations, mismapping, SNPs, sequencing errors, and a set of sites originating from the very first transcribed base (‘TSS sites’). We raise concerns as to whether the TSS sites truly reflect m1A originating from the first transcribed base. We find that only 53 of the sites detected in this study likely reflect bona-fide internal modifications of cytoplasmically encoded mRNA molecules. The vast majority of these are likely to be TRMT6/TRMT61A substrates, and are typically modified at low to undetectable levels. We conclude that within cytosolic mRNAs, m1A is a rare internal modification where it is typically catalyzed at ultra-low stoichiometries via TRMT6/TRMT61A. Our findings offer a clear and consistent view on the abundance and whereabouts of this modification, and lays out key directions for future studies in the field.
Functional recruitment of dynamin requires multimeric interactions for efficient endocytosis
Authors: Rosendale Morgane , Van Thi Nhu Ngoc , Grillo-Bosch Dolors , Sposini Silvia , Claverie Léa , Gauthereau Isabel , Claverol Stéphane , Choquet Daniel , Sainlos Matthieu , Perrais David
Published: April 2018

During clathrin mediated endocytosis (CME), membrane scission is achieved by the concerted action of dynamin and its interacting partners. Essential interactions occur between the proline/arginine-rich domain of dynamin (dynPRD) and the Src-homology domain 3 (SH3) of various proteins including amphiphysins. Here we show that multiple SH3 domains must bind simultaneously to dynPRD through three adjacent motifs for dynamin’s efficient recruitment and function. First, we show in dynamin triple knock-out cells that mutant dynamins modified in a single motif, including the central amphiphysin SH3 (amphSH3) binding motif, are partially capable of rescuing CME. However, mutating two motifs largely prevents that ability. To support this observation, we designed divalent dynPRD-derived peptides. These ligands bind multimers of amphSH3 with >100-fold higher affinity than monovalent onesin vitro. Accordingly, dialyzing living cells with these divalent peptides through a patch-clamp pipette blocks CME 2 to 3 times more effectively than with monovalent ones. Finally, the frequency of endocytic events decreases with competing peptides or hypomorphic rescue mutants but the kinetics of dynamin recruitment is unaffected. This suggests that PRD-SH3 interactions act upstream of dynamin accumulation at the neck of nascent vesicles. We conclude from these data that dynamin drives vesicle scissionviamultivalent interactionsin vivo.
DET1-mediated degradation of a SAGA-like deubiquitination module controls H2Bub homeostasis
Authors: Nassrallah Amr , Rougée Martin , Bourbousse Clara , Drevensek Stéphanie , Fonseca Sandra , Iniesto Elisa , Ait-Mohamed Ouardia , Deton-Cabanillas Anne-Flore , Zabulonb Gerald , Ahmed Ikhlak , Stroebel David , Masson Vanessa , Lombard Bérangère , Eeckhout Dominique , Gevaert Kris , Loew Damarys , Genovesio Auguste , Breyton Cécile , de Jaeger Geert , Bowler Chris , Rubio Vicente , Barneche Fredy
Published: April 2018

DE-ETIOLATED 1 (DET1) is an evolutionarily conserved component of the ubiquitination machinery that mediates the destabilization of key regulators of cell differentiation and proliferation in multicellular organisms. In this study, we provide evidence from Arabidopsis that DET1 is essential for the regulation of histone H2B monoubiquitination (H2Bub) over most genes by controlling the stability of a plant deubiquitination module (DUBm). In contrast with yeast and metazoan DUB modules that are associated with the large SAGA complex, the Arabidopsis DUBm only comprises three proteins (hereafter named SGF11, ENY2 and UBP22) and appears to act independently as a major H2Bub deubiquitinase activity. Our study further unveils that DET1-DDB1-Associated-1 (DDA1) protein interacts with SGF11in vivo, linking the DET1 complex to light-dependent ubiquitin-mediated proteolytic degradation of the DUBm. Collectively, these findings uncover a signaling path controlling DUBm availability, potentially adjusting H2Bub turnover capacity to the cell transcriptional status.
The Atomic Structure of the Microtubule-Nucleating γ-Tubulin Small Complex and its Implications for Regulation
Authors: Brilot Axel F. , Agard David A.
Published: April 2018

The microtubule cytoskeleton is essential in mediating a number of critical cellular processes, affecting cell shape, transport, organelle organization, and chromosomal segregation during mitosis. Microtubule network dynamics are controlled by many factors including the efficiency and localization of the nucleation machinery. Microtubule nucleation is dependent on the universally conserved γ-tubulin small complex (γTuSC), a 300 kDa heterotetramer composed of two copies of γ-tubulin and one each of accessory proteins GCP2 and GCP3. In yeast, nucleation is mediated by a heptameric ring of γTuSC, which presents 13 γ-tubulins to form a template for microtubule nucleation.

We have obtained single-particle structures of the γTuSC as a monomer and dimer at resolutions of 3.6-4.6Å, allowing us to build an atomic model for this important complex. By comparison with a crystal structure of isolated γ-tubulin, it is clear that γ-tubulin is activated upon assembly into the γTuSC, in a manner analogous to the bent to straight transition in αβ-tubulin upon assembly into the microtubule lattice. Our structures allow us to map phosphorylation sites, revealing several at key interfaces, highly suggestive of their role in regulating spindle pole body attachment and assembly into rings. When combined with previous lower resolution structures of helical assemblies, we observe that additional conformational changes occur during ring assembly and activation.
Identification of novel genes including rpmF and yjjQ critical for Type II persister formation in Escherichia coli
Authors: Liu Shuang , Wu Nan , Zhang Shanshan , Zhang Yumeng , Zhang Wenhong , Zhang Ying
Published: April 2018

Persister cells, which are characterized by inactive metabolism and tolerance to antibiotics or stresses, pose a significant challenge to the treatment of many persistent infections. Although multiple genes have been reported to be involved in persister formation through transposon mutant library screens, how persisters are formed during the natural process of persister formation as the culture transitions from log phase to stationary phase is unclear. Here, using E. coli as a model, we performed a comprehensive transcriptome analysis of gene expression profiles of successive cultures of an E. coli culture at different critical time points, starting from persister-free S1-nonexistence phase (3h) to persister appearing S2-emergence phase (4h), and persister abundant stage S3-abundance phase (5h). The differentially expressed genes (≥2-fold) in persister appearing stage (S1 to S2 transition) and persister abundant stage (S1 to S3) were compared, and 51 and 29 genes were identified to be up-regulated, respectively. Importantly, 13 genes (gnsA, gnsB, ybfA, yjjQ, ymdF, yhdU, csgD, yncN, rpmF, ydcX, yohJ, ssrA, rbsD) overlap in both persister S2-emergence phase and S3-abundance phase, including a member of the trans-translation pathway (ssrA) as well as an orphan toxin (ydcX), which are two well-known persister genes while the remaining 11 novel genes (gnsA, gnsB, ybfA, yjjQ, ymdF, yhdU, csgD, yncN, rpmF, yohJ, rbsD) have not been reported previously. Persister levels of 7 constructed knockout mutants (ΔgnsA, ΔybfA, ΔyjjQ, ΔyhdU, ΔcsgD, ΔyohJ and ΔrpmF) and 10 overexpression strains (gnsA, gnsB, ybfA, yjjQ, ymdF, yhdU, csgD, rpmF, yohJ, rbsD) in E. coli uropathogenic strain UTI89 were determined upon treatment with different cidal antibiotics (ampicillin, levofloxacin and gentamicin). Additionally, ranking of these overlapping genes according to their impact on persister levels were also performed. Two genes (rpmF encoding 50S ribosomal subunit protein L32, and yjjQ encoding a putative LuxR-type transcription factor) showed the most obvious phenotype on persister levels in both knockout and overexpression studies, which suggests they are broad and key factors for persister formation. While previous studies cannot distinguish if a given persister gene is involved in persister formation or persister survival, our findings clearly identify novel persister forming genes and pathways involving a ribosome protein and a LuxR type transcription factor during the bona fide persister formation process and may have implications for developing improved treatment of persistent infections.
Spc110 N-Terminal Domains Act Independently to Mediate Stable γ-Tubulin Small Complex Binding and γ-Tubulin Ring Complex Assembly
Authors: Lyon Andrew , Zelter Alex , Viswanath Shruthi , Maxwell Alison , Johnson Richard , Yabut King Clyde B. , MacCoss Michael , Davis Trisha N. , Muller Eric , Sali Andrej , Agard David A.
Published: April 2018

Microtubule (MT) nucleation in vivo is regulated by the γ-tubulin ring complex (γTuRC), an approximately 2-megadalton complex conserved from yeast to humans. In Saccharomyces cerevisiae, γTuRC assembly is a key point of regulation over the MT cytoskeleton. Budding yeast γTuRC is composed of seven γ-tubulin small complex (γTuSC) subassemblies which associate helically to form a template from which microtubules grow. This assembly process requires higher-order oligomers of the coiled-coil protein Spc110 to bind multiple γTuSCs, thereby stabilizing the otherwise low-affinity interface between γTuSCs. While Spc110 oligomerization is critical, its N-terminal domain (NTD) also plays a role that is poorly understood both functionally and structurally. In this work, we sought a mechanistic understanding of Spc110 NTD using a combination of structural and biochemical analyses. Through crosslinking-mass spectrometry (XL-MS), we determined that a segment of Spc110 coiled-coil is a major point of contact with γTuSC. We determined the structure of this coiled-coil segment by X-ray crystallography and used it in combination with our XL-MS dataset to generate an integrative structural model of the γTuSC-Spc110 complex. This structural model, in combination with biochemical analyses of Spc110 heterodimers lacking one NTD, suggests that the two NTDs within an Spc110 dimer act independently, one stabilizing association between Spc110 and γTuSC and the other stabilizing the interface between adjacent γTuSCs.
A feeding aggregation of Omura‘s whale Balaenoptera omurai off Nosy Be, Mozambique Channel
Authors: Laboute Pierre , Borsa Philippe
Published: April 2018

A feeding aggregation of Omura’s whales Balaenoptera omurai was documented off Nosy Be Island at the northeastern entrance of Mozambique Channel in November 1994. Underwater photographs of live individuals illustrated sub-surface skimming as main feeding behaviour, with small crustaceans, small jellyfish, and other gelatinous micronecton identified as prey. A precise description of the whales’ pigmentation patterns completes previous descriptions from the recent literature.
Cholesterol boundPlasmodium falciparumco-chaperone ‘PFA0660w’ complexes with major virulence factor ‘PfEMP1’ via chaperone ‘PfHsp70-x’
Authors: Behl Ankita , Kumar Vikash , Bisht Anjali , Panda Jiban J. , Hora Rachna , Mishra Prakash Chandra
Published: April 2018

Lethality ofPlasmodium falciparum(Pf) caused malaria results from ‘cytoadherence’, which is effected by exportedPlasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) family. Several exported Pf proteins (exportome) including chaperones alongside cholesterol rich microdomains are crucial for PfEMP1 translocation to infected erythrocyte surface. An exported Hsp40 (heat shock protein 40) ‘PFA0660w’ functions as a co-chaperone of ‘PfHsp70-x’, and these co-localize to specialized intracellular mobile structures termed J-dots. Our studies attempt to understand the function of PFA0660w-PfHsp70-x chaperone pair using recombinant proteins. Biochemical assays reveal that N and C-terminal domains of PFA0660w and PfHsp70-x respectively are critical for their activity. We show the novel direct interaction of PfHsp70-x with the cytoplasmic tail of PfEMP1, and binding of PFA0660w with cholesterol. PFA0660w operates both as a chaperone and lipid binding molecule via its separate substrate and cholesterol binding sites. PfHsp70-x binds cholesterol linked PFA0660w and PfEMP1 simultaneouslyin vitroto form a complex. Collectively, our results and the past literature support the hypothesis that PFA0660w-PfHsp70-x chaperone pair assists PfEMP1 transport across the host erythrocyte through cholesterol containing ‘J-dots’. Since PFA0660w seems essential for parasite survival, characterization of its interaction with PfHsp70-x and J-dots may form the basis for development of future antimalarials.