As the Zika virus is rapidly taking hold around the world, health officials are racing to find its cause and prevent further spread of the […]

The post Smithsonian’s mosquito collection is weapon in battle against Zika appeared first on Smithsonian Insider.

This brief squid made a surprise appearance in a Smithsonian Environmental Research Center trawl survey at the mouth of Maryland’s Rhode River last Thursday—the first […]

The post Brief squid surprise appeared first on Smithsonian Insider.

With roughly 5,500 individuals remaining in the wild, the black rhino population is critically endangered. To help save these iconic African giants, at risk for […]

The post A Planet in Peril: Q&A with Suzan Murray of the Smithsonian Global Health Program appeared first on Smithsonian Insider.

In 1935, 101 cane toads from Hawaii were set loose in Australia to help control beetles that were decimating the Australian sugar crop. But instead […]

The post Discovery: Australia’s invasive cane toads modify their bodies to conquer new territory faster appeared first on Smithsonian Insider.

Fetching close to $1,500 per pound, ivory ranks fourth in black-market traded items just behind illegal drugs, weapons, and humans. Governments across the globe are […]

The post New technique may help authorities quickly ID real and fake ivory products appeared first on Smithsonian Insider.

AUSTIN, Texas — Astronomers at The University of Texas at Austin and Harvard University have put a basic principle of black holes to the test, […]

The post Do Stars Fall Quietly into Black Holes? appeared first on Smithsonian Insider.

In conflicts between predators and prey, speed is a decided advantage, and evolution has given the trap-jaw ant a distinct advantage with spring-loaded jaws that […]

The post Locked and loaded: unique trigger design fires this ant’s snapping jaws appeared first on Smithsonian Insider.

Flying through the air? Check. Surviving snake bites? Check. One of the most adorable creatures on earth? Absolutely! Do you think you know everything about […]

The post This Squirrel Appreciation Day we have a few surprising squirrely facts for you appeared first on Smithsonian Insider.

The biological processes related to protein homeostasis in Mycobacterium tuberculosis, the etiologic agent of tuberculosis, have recently been established as critical pathways for therapeutic intervention. Proteins of particular interest are ClpC1 and the ClpC1–ClpP1–ClpP2 proteasome complex. The structure of the potent antituberculosis macrocyclic depsipeptide ecumicin complexed with the N-terminal domain of ClpC1 (ClpC1-NTD) is presented here. Crystals of the ClpC1-NTD–ecumicin complex were monoclinic (unit-cell parameters a = 80.0, b = 130.0, c = 112.0 Å, β = 90.07°; space group P21; 12 complexes per asymmetric unit) and diffracted to 2.5 Å resolution. The structure was solved by molecular replacement using the self-rotation function to resolve space-group ambiguities. The new structure of the ecumicin complex showed a unique 1:2 (target:ligand) stoichiometry exploiting the intramolecular dyad in the α-helical fold of the target N-terminal domain. The structure of the ecumicin complex unveiled extensive interactions in the uniquely extended N-terminus, a critical binding site for the known cyclopeptide complexes. This structure, in comparison with the previously reported rufomycin I complex, revealed unique features that could be relevant for understanding the mechanism of action of these potential antituberculosis drug leads. Comparison of the ecumicin complex and the ClpC1-NTD-L92S/L96P double-mutant structure with the available structures of rufomycin I and cyclomarin A complexes revealed a range of conformational changes available to this small N-terminal helical domain and the minor helical alterations involved in the antibiotic-resistance mechanism. The different modes of binding and structural alterations could be related to distinct modes of action.

Death-associated protein kinase 1 (DAPK1) is a serine/threonine protein kinase that regulates apoptosis and autophagy. DAPK1 is considered to be a therapeutic target for amyloid-β deposition, endometrial adenocarcinomas and acute ischemic stroke. Here, the potent inhibitory activity of the natural anthraquinone purpurin against DAPK1 phosphorylation is shown. Thermodynamic analysis revealed that while the binding affinity of purpurin is similar to that of CPR005231, which is a DAPK1 inhibitor with an imidazopyridazine moiety, the binding of purpurin was more enthalpically favorable. In addition, the inhibition potencies were correlated with the enthalpic changes but not with the binding affinities. Crystallographic analysis of the DAPK1–purpurin complex revealed that the formation of a hydrogen-bond network is likely to contribute to the favorable enthalpic changes and that stabilization of the glycine-rich loop may cause less favorable entropic changes. The present findings indicate that purpurin may be a good lead compound for the discovery of inhibitors of DAPK1, and the observation of enthalpic changes could provide important clues for drug development.

Only the Wing is a new book by Russell Lee that recounts Horten's epic quest to stabalize and control the all-wing aircraft.

The post New Book: “Only the Wing: Reimar Horten’s Epic Quest to Stabilize and Control the All-Wing Aircraft” appeared first on Smithsonian Insider.

Juan Martin D'Ambrosio, Veronique Albanese, Nicolas-Frederic Lipp, Lucile Fleuriot, Delphine Debayle, Guillaume Drin, and Alenka Copic

Osh6 and Osh7 are lipid transfer proteins (LTPs) that move phosphatidylserine (PS) from the endoplasmic reticulum (ER) to the plasma membrane (PM). High PS level at the PM is key for many cellular functions. Intriguingly, Osh6/7 localize to ER-PM contact sites, although they lack membrane-targeting motifs, in contrast to multidomain LTPs that both bridge membranes and convey lipids. We show that Osh6 localization to contact sites depends on its interaction with the cytosolic tail of the ER-PM tether Ist2, a homologue of TMEM16 proteins. We identify a motif in the Ist2 tail, conserved in yeasts, as the Osh6-binding region, and we map an Ist2-binding surface on Osh6. Mutations in the Ist2 tail phenocopy osh6 osh7 deletion: they decrease cellular PS levels, and block PS transport to the PM. Our study unveils an unexpected partnership between a TMEM16-like protein and a soluble LTP, which together mediate lipid transport at contact sites.

Fluorite is well known and prized for its rich variety of colors, most commonly pale green, purple, yellow, orange, blue, pink and colorless. “We acquired this specimen because it is a very nice quality fluorite with an attractive color and it is large enough to be exhibited,” Curator Jeff Post says.

The post Smithsonian’s National Gem Collection acquires a yellow fluorite from Tanzania appeared first on Smithsonian Insider.

The Smithsonian’s National Museum of Natural History recently acquired four remarkable gemstones and jewelry pieces for the Smithsonian’s National Gem Collection in celebration of the 100th anniversary of the museum.

The post National Museum of Natural History acquires gemstones in honor of its 100th anniversary appeared first on Smithsonian Insider.

Richard Wunderman is managing editor of the Bulletin of the Global Volcanism Network and a geologist in the Division of Mineral Sciences at the Smithsonian’s […]

The post Q&A: Smithsonian volcanologist Richard Wunderman answers questions about the Aug. 23, East Coast earthquake appeared first on Smithsonian Insider.

The National Museum of Natural History will permanently display the Dom Pedro Aquamarine, which is the largest single piece of cut-gem aquamarine in the world, beginning Dec. 6.

The post Magnificent Dom Pedro aquamarine to go on view in the Smithsonian’s Natural History Museum appeared first on Smithsonian Insider.

The transformations from the primitive cells of the centered Bravais lattices to the corresponding centered cells have conventionally been listed as three-by-three matrices that transform three-space lattice vectors. Using those three-by-three matrices when working in the six-dimensional space of lattices represented as Selling scalars as used in Delone (Delaunay) reduction, one could transform to the three-space representation, apply the three-by-three matrices and then back-transform to the six-space representation, but it is much simpler to have the equivalent six-by-six matrices and apply them directly. The general form of the transformation from the three-space matrix to the corresponding matrix operating on Selling scalars (expressed in space S6) is derived, and the particular S6matrices for the centered Delone types are listed. (Note: in his later publications, Boris Delaunay used the Russian version of his surname, Delone.)

In this study, the atomic structure of the ternary icosahedral ZnMgTm quasicrystal (QC) is investigated by means of single-crystal X-ray diffraction. The structure is found to be a member of the Bergman QC family, frequently found in Zn–Mg–rare-earth systems. The ab initio structure solution was obtained by the use of the Superflip software. The infinite structure model was founded on the atomic decoration of two golden rhombohedra, with an edge length of 21.7 Å, constituting the Ammann–Kramer–Neri tiling. The refined structure converged well with the experimental diffraction diagram, with the crystallographic R factor equal to 9.8%. The Bergman clusters were found to be bonded by four possible linkages. Only two linkages, b and c, are detected in approximant crystals and are employed to model the icosahedral QCs in the cluster approach known for the CdYb Tsai-type QC. Additional short b and a linkages are found in this study. Short interatomic distances are not generated by those linkages due to the systematic absence of atoms and the formation of split atomic positions. The presence of four linkages allows the structure to be pictured as a complete covering by rhombic triacontahedral clusters and consequently there is no need to define the interstitial part of the structure (i.e. that outside the cluster). The 6D embedding of the solved structure is discussed for the final verification of the model.

The generalized Darwin–Hamilton equations [Wuttke (2014). Acta Cryst. A70, 429–440] describe multiple Bragg reflection from a thick, ideally imperfect crystal. These equations are simplified by making full use of energy conservation, and it is demonstrated that the conventional two-ray Darwin–Hamilton equations are obtained as a first-order approximation. Then an efficient numeric solution method is presented, based on a transfer matrix for discretized directional distribution functions and on spectral collocation in the depth coordinate. Example solutions illustrate the orientational spread of multiply reflected rays and the distortion of rocking curves, especially if the detector only covers a finite solid angle.

The post Smithsonian geologist Liz Cottrell discusses the March 11, 2011 Japan earthquake and its mechanics appeared first on Smithsonian Insider.

Q?rius is a new way for teens and tweens – and their families and educators – to connect science with everyday experiences. With a name […]

The post Q?rius appeared first on Smithsonian Insider.

The nation’s top bird science and conservation groups have come together to publish The State of the Birds 2014—the most comprehensive review of long-term trend […]

The post The State of the Birds: Q&A with Peter Marra appeared first on Smithsonian Insider.

No divers were in danger when two large squid (species Taningia danae) began acting aggressively toward a robot submersible operated deep in the Pacific from NOAA’s […]

The post Rare squid “T. danae” captured in new video appeared first on Smithsonian Insider.

Food is an important element of Basque life. In the Ostatua Kitchen tent at the Smithsonian’s 2016 Folklife Festival, chefs from two Basque culinary schools […]

The post Basque Country & Cheese appeared first on Smithsonian Insider.

Aukeran is a professional dance troupe from Basque country founded in 1997 by Edu Muruamendiaraz. The beautiful and graceful professional dancers have backgrounds in both […]

The post Basque Dance Troupe “Aukeran” at Smithsonian Folklife Festival appeared first on Smithsonian Insider.

The French-German border is littered with as many as 500 underground sites used during World War I. Researcher Jeff Gusky explores them and finds a […]

The post Quarry carvings by American WWI soldiers appeared first on Smithsonian Insider.

For more than twenty years, Vaquero, a monumental sculpture by Luis Jiménez, has greeted visitors as they enter the Smithsonian American Art Museum. Art conservator […]

The post Vaquero Returns! appeared first on Smithsonian Insider.

This animation tells a Cheyenne story of how the Big Dipper came to be when a girl and her loyal brothers escape from a bison. […]

The post Quillwork Girl and Her New Seven Brothers appeared first on Smithsonian Insider.

Jose Loaiza, a research associate at the Smithsonian Tropical Research Institute in Panama, has determined that disease carrying mosquitoes move along Panama’s highways by laying […]

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Recent analysis using DNA sequencing of ancient Roman pills found aboard a ship that sank in Italy’s Gulf of Baratti between 140 -120 B.C, has revealed that the medicines consist of material from simple garden plants, namely carrot, radish, parsley, celery, wild onion and cabbage.

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Recent botanical exploration efforts in the rugged Marquesas Islands (French Polynesia) have increased the known flora of the archipelago by an impressive 20 percent. Field research and collecting in conjunction with the Vascular Flora of the Marquesas Islands and Flore de la Polynesie française projects have yielded 62 new species of ferns and flowering plants bringing the total native species to 360, of which 18 are newly described and illustrated in a special issue of PhytoKeys.

The post Marquesas Islands in French Polynesia yield 18 new species of rare ferns and flowering plants appeared first on Smithsonian Insider.

Despite many laws to protect it, a new survey reveals wild ginseng in Maryland is on the decline.

The post Wild ginseng in steep decline in Maryland, survey reveals: Q&A with Smithsonian botanist Christopher Puttock appeared first on Smithsonian Insider.

Katie Cramer is a MarineGEO Post-Doctoral Fellow and travels to Smithsonian Tropical Research Institute in Panama throughout the year to conduct research. Her recent paper […]

The post Q&A: Katie Cramer on the long term human impact on coral reefs in Caribbean Panama appeared first on Smithsonian Insider.

Do you enjoy Tequila? Then you need to raise your glass to the pollinating bats that helped to make it! Here at Smithsonian Science we […]

The post Love tequila? A toast to pollinating bats! appeared first on Smithsonian Insider.

Visitors to the tropics are amazed by the huge variety of colorful, complex and sometimes ferocious creatures living near the equator. Smithsonian scientists and colleagues […]

The post Is This the Long-Sought Answer to the Question of Tropical Biodiversity? appeared first on Smithsonian Insider.

An elementary method is described for finding the coordination sequences for a tiling, based on coloring the underlying graph. The first application is to the two kinds of vertices (tetravalent and trivalent) in the Cairo (or dual-32.4.3.4) tiling. The coordination sequence for a tetravalent vertex turns out, surprisingly, to be 1, 4, 8, 12, 16, …, the same as for a vertex in the familiar square (or 44) tiling. The authors thought that such a simple fact should have a simple proof, and this article is the result. The method is also used to obtain coordination sequences for the 32.4.3.4, 3.4.6.4, 4.82, 3.122 and 34.6 uniform tilings, and the snub-632 tiling. In several cases the results provide proofs for previously conjectured formulas.

One of the essential components of molecular electronic circuits are switching elements that are stable in two different states and can ideally be switched on and off many times. Here, distinct buckminsterfullerenes within a self-assembled monolayer, forming a two-dimensional dodecagonal quasicrystal on a Pt-terminated Pt3Ti(111) surface, are identified to form well separated molecular rotational switching elements. Employing scanning tunneling microscopy, the molecular-orbital appearance of the fullerenes in the quasicrystalline monolayer is resolved. Thus, fullerenes adsorbed on the 36 vertex configuration are identified to exhibit a distinctly increased mobility. In addition, this finding is verified by differential conductance measurements. The rotation of these mobile fullerenes can be triggered frequently by applied voltage pulses, while keeping the neighboring molecules immobile. An extensive analysis reveals that crystallographic and energetic constraints at the molecule/metal interface induce an inequality of the local potentials for the 36 and 32.4.3.4 vertex sites and this accounts for the switching ability of fullerenes on the 36 vertex sites. Consequently, a local area of the 8/3 approximant in the two-dimensional fullerene quasicrystal consists of single rotational switching fullerenes embedded in a matrix of inert molecules. Furthermore, it is deduced that optimization of the intermolecular interactions between neighboring fullerenes hinders the realization of translational periodicity in the fullerene monolayer on the Pt-terminated Pt3Ti(111) surface.