WHAT A new species of stick catfish from South America, so called because the thin, elongated bodies of these fish mimic sticks. About 5 inches […]

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The name Panama is said to mean “abundance of fish.” Now a new study estimates that between 1950 and 2010, the amount of fish taken […]

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In one of the largest studies of its kind, a volunteer-fueled camera trapping effort showed that where coyotes have moved in, cats are nowhere to […]

The post Cats Don’t Roam in Places Coyotes Call Home appeared first on Smithsonian Insider.

DNA analysis is proving to be a valuable tool for scientists trying to gauge the environmental impact that invasive blue catfish (Ictalurus furcatus) and flathead […]

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Scientists at the Smithsonian Tropical Research Institute (STRI) in Panama compared the diets of two caterpillar species, expecting the one that exclusively consumed plants containing […]

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Higher acidity in coastal waters can make fish more sensitive to low oxygen, causing them to become debilitated and suffocate in water with oxygen levels […]

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Amid efforts to restore native oyster populations on the West Coast, how are oysters expected to fare under climate change in the decades and centuries […]

The post Climate Change May Benefit Native Oysters, but There’s a Catch appeared first on Smithsonian Insider.

Four years after conservationists relocated 570 desert tortoises (Gopherus agassizii) in California from a threatened habitat to a new nearby location, the tortoises outwardly appeared […]

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When fast radio bursts, or FRBs, were first detected in 2001, astronomers had never seen anything like them before. Since then, astronomers have found a […]

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Cats are notoriously fickle—purring in your lap one second, then swiping you with an indignant claw the next. One thing is certain however when it […]

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A new study from the Smithsonian Conservation Biology Institute (SCBI) is helping make headway in an area of animal management that has historically proven challenging: […]

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Little to nothing is known about how and where a small European songbird called the bluethroat spends much of the year. Now, Smithsonian scientists have […]

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Victor J. F. Kitano, Yoko Ohyama, Chiyomi Hayashida, Junta Ito, Mari Okayasu, Takuya Sato, Toru Ogasawara, Maki Tsujita, Akemi Kakino, Jun Shimada, Tatsuya Sawamura, and Yoshiyuki Hakeda

Osteoporosis is associated with vessel diseases attributed to hyperlipidemia, and bone resorption by multinucleated osteoclasts is related to lipid metabolism. In this study, we generated low-density lipoprotein receptor (LDLR)/lectin-like oxidized LDL receptor-1 (LOX-1) double knockout (dKO) mice. We found that, like LDLR single KO (sKO), LDLR/LOX-1 dKO impaired cell-cell fusion of osteoclast-like cells (OCLs). LDLR/LOX-1 dKO and LDLR sKO preosteoclasts exhibited decreased uptake of LDL. The cell surface cholesterol levels of both LDLR/LOX-1 dKO and LDLR sKO osteoclasts were lower than the levels of wild-type OCLs. Additionally, the amount of phosphatidylethanolamine (PE) on the cell surface was attenuated in LDLR/LOX-1 dKO and LDLR sKO pre-OCLs, while the PE distribution in wild-type OCLs was concentrated on the filopodia in contact with neighboring cells. Abrogation of the ATP binding cassette G1 (ABCG1) transporter, which transfers PE to the cell surface, caused decreased PE translocation to the cell surface and subsequent cell-cell fusion. The findings of this study indicate the involvement of a novel cascade (LDLR~ABCG1~PE translocation to cell surface~cell-cell fusion) in multinucleation of OCLs.

Sanjeev Chavan Nayak and Vegesna Radha

C3G (RapGEF1) plays a role in cell differentiation and is essential for early embryonic development in mice. In this study, we identify C3G as a centrosomal protein colocalizing with cenexin at the mother centriole in interphase cells. C3G interacts through its catalytic domain with cenexin, and they show interdependence for localization to the centrosome. C3G depletion caused a decrease in cellular cenexin levels. Centrosomal localization is lost as myocytes differentiate to form myotubes. Stable clone of cells depleted of C3G by CRISPR/Cas9 showed the presence of supernumerary centrioles. Overexpression of C3G, or a catalytically active deletion construct inhibited centrosome duplication. Cilia length is longer in C3G knockout cells, and the phenotype could be reverted upon reintroduction of C3G or its catalytic domain. Association of C3G with the basal body is dynamic, decreasing upon serum starvation, and increasing upon reentry into the cell cycle. C3G inhibits cilia formation and length dependent on its catalytic activity. We conclude that C3G inhibits centrosome duplication and maintains ciliary homeostasis, properties that may be important for its role in embryonic development.

According to the weekly report of the Smithsonian’s Global Volcanism Program, gas-and-ash plumes rose nearly one mile above the crater of Mexico’s Popocatépetl volcano from […]

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Relativistic electron diffraction depends on linear and quadratic terms in the electric potential, the latter being neglected in the frequently used relativistically corrected Schrödinger equation. The quadratic electric potential term modifies atomic scattering amplitudes in particular for large-angle scattering and backscattering. The respective correction increases with increasing scattering angle, increasing atomic number and increasing kinetic energy. Conventional tabulations for electron scattering and its large-angle extrapolations can be amended in closed form by a universal correction based on the screened Coulomb potential squared.

What does it take to care for a pride of lions? Go behind the scenes with Great Cats Curator Craig Saffoe as he works with animal keepers and veterinarians to prepare the National Zoo's frisky lion cubs for their public debut. For more about the Zoo's growing pride and to watch them on live webcams: http://nationalzoo.si.edu/Animals/GreatCats/default.cfm?cam=LC4

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It takes a Tlingit artist up to 2,000 hours, or 83 days, to weave just one ceremonial robe. Not surprisingly, this art form is practiced by a dedicated few including Tlingit artists Teri Rofkar and Shelly Laws of Alaska. In their presentation for the Smithsonian Spotlight series hosted by the Arctic Studies Center at the Anchorage Museum, Rofkar and Laws discuss the methods and cultural significance of robes, spruce root baskets and more.
For more information, go to http://www.mnh.si.edu/arctic/html/alaska.htm

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The Smithsonian Science Education Center (formerly NSRC) was formed by the Smithsonian Institution and the National Academies in 1985 with the mission to improve the learning and teaching of science in school districts in the United States and throughout the world.

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What is it like to be the curator of Great Cats at the National Zoo? We interviewed Craig Saffoe to hear firsthand.

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Ted Schultz, research entomologist at Smithsonian’s National Museum of Natural History, describes how ants use their incredible sense of smell along with their ability to […]

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Knowing what we take from our oceans matters. Smithsonian scientists are developing tools to better understand and protect our oceans. One project they are working […]

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Catherine McKenna, Canada’s Minister of the Environment and Climate Change, talks about the importance of bird conservation and why birds really matter. Step outside your […]

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Meet Amy Homma, the Director of Digital Learning at Art Lab+. Learn how Smithsonian’s Hirshhorn Museum and Sculpture Garden has created a dynamic program to […]

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On the morning of Monday, Jan. 30, 2017 a 25-pound female bobcat cat was discovered missing from its exhibit at the Smithsonian’s National Zoo in […]

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Ollie the bobcat, who escaped from her enclosure at the Smithsonian National Zoo, was found two days after her disappearance roaming near the zoo’s bird […]

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The Smithsonian’s National Museum of African Art is the first institution to acquire the deeply personal and visually mesmerizing video projections “Invocation: The Severance of […]

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Smithsonian Tropical Research Institute MarineGEO Postdoctoral Fellow Maggie Johnnson outlines her research studying the effects of ocean acidification on marine coral near Bocas del Toro, […]

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If you see a web site that states "Press <> to watch the video" and then prompts you to allow browser notifications, do not click on the allow button. These sites are just trying to trick you into subscribing to their browser notifications so that they can send notification spam directly to your desktop.

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The Smithsonian Environmental Research Center in Edgewater, Md., and the Alaska Sea Grant Program of the University of Alaska, Fairbanks, were recently identified as the […]

The post Smithsonian scientists to help identify and eradicate invasive species in Alaskan waters appeared first on Smithsonian Insider.

They’ve got no roots or veins and grow in hanging pendants or tightly packed mats attached to stones, soil and wood. Called by some “the […]

The post Mosses have strong potential to acclimate to global warming, study indicates appeared first on Smithsonian Insider.

By simulating the environment when corn was first exploited by people and then domesticated, Smithsonian scientists discovered that corn’s ancestor; a wild grass called teosinte, […]

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With net in hand and eyes peeled, Mauren Turcatel spent two-weeks last October chasing blood-thirsty predators through the Amazon jungle of Brazil. One-by-one they appeared […]

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Skinny lines of ants snake through the rainforest carrying leaves and flowers above their heads—fertilizer for industrial-scale, underground fungus farms. Soon after the dinosaur extinctions […]

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The structural and nonlinear optical properties of a new anilinium hybrid crystal of chemical formula (C6H7NCl+·NO3−)3 have been investigated. The crystal structure was determined from single-crystal X-ray diffraction measurements performed at a temperature of 100 K which show that the compound crystallizes in a noncentrosymmetric space group (Pna21). The structural analysis was coupled with Hirshfeld surface analysis to evaluate the contribution of the different intermolecular interactions to the formation of supramolecular assemblies in the solid state that exhibit nonlinear optical features. This analysis reveals that the studied compound is characterized by a three-dimensional network of hydrogen bonds and the main contributions are provided by the O...H, C...H, H...H and Cl...H interactions, which alone represent ∼85% of the total contributions to the Hirshfeld surfaces. It is noteworthy that the halogen...H contributions are quite comparable with those of the H...H contacts. The nonlinear optical properties were investigated by nonlinear diffuse femtosecond-pulse reflectometry and the obtained results were compared with those of the reference material LiNbO3. The hybrid crystals exhibit notable second (SHG) and third (THG) harmonic generation which confirms its polarity is generated by the different intermolecular interactions. These measurements also highlight that the THG signal of the new anilinium compound normalized to its SHG counterpart is more pronounced than for LiNbO3.

Compared with X-rays, electron diffraction faces a crucial challenge: dynamical electron scattering compromises structure solution and its effects can only be modelled in specific cases. Dynamical scattering can be reduced experimentally by decreasing crystal size but not without a penalty, as it also reduces the overall diffracted intensity. In this article it is shown that nanometre-sized crystals from organic pharmaceuticals allow positional refinement of the hydrogen atoms, even whilst ignoring the effects of dynamical scattering during refinement. To boost the very weak diffraction data, a highly sensitive hybrid pixel detector was employed. A general likelihood-based computational approach was also introduced for further reducing the adverse effects of dynamic scattering, which significantly improved model accuracy, even for protein crystal data at substantially lower resolution.

A new aspherical scattering factor formalism has been implemented in the crystallographic least-squares refinement program SHELXL. The formalism relies on Gaussian functions and can optionally complement the independent atom model to take into account the deformation of electron-density distribution due to chemical bonding and lone pairs. Asphericity contributions were derived from the electron density obtained from quantum-chemical density functional theory computations of suitable model compounds that contain particular chemical environments, as defined by the invariom formalism. Thanks to a new algorithm, invariom assignment for refinement in SHELXL is automated. A suitable parameterization for each chemical environment within the new model was achieved by metaheuristics. Figures of merit, precision and accuracy of crystallographic least-squares refinements improve significantly upon using the new model.

Diffuse scattering is a rich source of information about disorder in crystalline materials, which can be modelled using atomistic techniques such as Monte Carlo and molecular dynamics simulations. Modern X-ray and neutron scattering instruments can rapidly measure large volumes of diffuse-scattering data. Unfortunately, current algorithms for atomistic diffuse-scattering calculations are too slow to model large data sets completely, because the fast Fourier transform (FFT) algorithm has long been considered unsuitable for such calculations [Butler & Welberry (1992). J. Appl. Cryst. 25, 391–399]. Here, a new approach is presented for ultrafast calculation of atomistic diffuse-scattering patterns. It is shown that the FFT can actually be used to perform such calculations rapidly, and that a fast method based on sampling theory can be used to reduce high-frequency noise in the calculations. These algorithms are benchmarked using realistic examples of compositional, magnetic and displacive disorder. They accelerate the calculations by a factor of at least 102, making refinement of atomistic models to large diffuse-scattering volumes practical.

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The enanti­opure monopyrrolidine derivative (2S)-methyl (Z)-5-(2-tert-but­oxy-1-cyano-2-oxo­ethyl­idene)pyrrolidine-2-carboxyl­ate, C13H18N2O4, (1), represents a potential ligand and an attractive inter­mediate for the synthesis of chiral metal com­plexes. At the mol­ecular level, the com­pound features an intra­molecular N—H⋯O hydrogen bond; neighbouring mol­ecules inter­act via N—H⋯N contacts to form chains along [100]. Due to its elemental com­position, resonant scattering of the target com­pound is entirely insignificant for diffraction experiments with Mo Kα and small even for Cu Kα radiation. A preliminary study with the harder radiation type confirmed the chiral space group and the suitability of the single crystal chosen; as expected, the results concerning the absolute structure remained com­pletely inconclusive. A second data collection with the longer wavelength gave satisfactory quality indicators for the correct handedness of the mol­ecule, albeit with high standard uncertainties. The absolute configuration has been assessed independently: CD spectra for both enanti­omers of the target mol­ecule were calculated and the spectrum for the S-configured stereoisomer was in agreement with the experiment. The Cotton effect of (1) may be ascribed to π–π* transitions from HOMO to LUMO and from HOMO to LUMO+1. As both independent techniques agree with respect to the handedness of the target mol­ecule, the absolute structure may be assigned with a high degree of confidence.

The com­pound poly[2-hy­droxy-N-methyl­ethan-1-aminium [μ3-cyanido-κ3C:C:N-di-μ-cyanido-κ4C:N-dicuprate(I)]], {(C3H10NO)[Cu2(CN)3]}n or [meoenH]Cu2(CN)3, crystallizes in the tetra­gonal space group P43. The structure consists of a three-dimensional (3D) anionic CuICN network with noncoordinated protonated N-methyl­ethano­lamine cations providing charge neutrality. Pairs of cuprophilic Cu atoms are bridged by the C atoms of μ3-cyanide ligands, which link these units into a 43 spiral along the c axis. The spirals are linked together into a 3D anionic network by the two other cyanide groups. The cationic moieties are linked into their own 43 spiral via N—H⋯O and O—H⋯O hydrogen bonds, and the cations inter­act with the 3D network via an unusual pair of N—H⋯N hydrogen bonds to one of the μ2-cyanide groups. Thermogravimetric analysis indicates an initial loss of the base cation and one cyanide as HCN at temperatures in the range 130–250 °C to form CuCN. We show how loss of a specific cyanide group from the 3D CuCN structure could form the linear CuCN structure. Further heating leaves a residue of elemental copper, isolated as the oxide.

The Debye scattering equation (DSE) is generalized and augmented in order to account for moderate texture effects, yielding the differential cross section as a function of atomic coordinates and texture coefficients subject to symmetry constraints. Implications for the evaluation of the pair distribution function (PDF) as a direct transform of powder diffraction data from textured samples are also discussed.