All bear species except for one live in either temperate or tropical woodlands. Only the polar bear is a stranger to the forest, living and […]

The post Polar bears in a warming world: Q&A with Don Moore of the National Zoo appeared first on Smithsonian Insider.

The impact of industrial fishing on coastal ecosystems has been studied for many years. But how it affects food webs in the open ocean―a vast […]

The post Scientists find impact of open-ocean industrial fishing within centuries of bird bones appeared first on Smithsonian Insider.

A fiery explosion on the surface of the Moon, visible to the naked eye, recently surprised NASA astronomers monitoring the Moon for meteorite strikes. Occurring […]

The post A meteorite explodes on the Moon: Q&A with geophysicist Bruce Campbell appeared first on Smithsonian Insider.

Roses, carnations and lilies are today among the most popular flowers people use to express sympathy and condolence. The simple act of sending flowers to […]

The post Funeral flowers in the Stone Age: Q&A with Smithsonian anthropologist Reuven Yeshurun appeared first on Smithsonian Insider.

Hot spots of mercury pollution in aquatic sediments and soils can contaminate local food webs and threaten ecosystems, but cleaning them up can be expensive […]

The post Toxicity of mercury hot spots can be reduced with application of activated carbon, researchers discover appeared first on Smithsonian Insider.

It is one of the most sensitive noses in the animal kingdom but what its owner seeks is no pungent bed of roses, in fact […]

The post Study shows turkey vulture is doubly blessed with acute vision and sense of smell appeared first on Smithsonian Insider.

  The surface of Venus is hidden beneath a perpetual blanket of clouds, but radar allows scientists at the National Air and Space Museum to […]

The post Mapping Venus with radar appeared first on Smithsonian Insider.

Santa Claus and his sleigh full of gifts has been upstaged early this holiday season by news of autonomous drones possibly delivering packages to your […]

The post Package-delivering drones? Q&A with Roger Connor of the National Air and Space Museum appeared first on Smithsonian Insider.

Ants dominate the earth’s ecosystems and many are voracious predators that use their mandibles and sheer numbers to pin down and tear apart most other […]

The post Carabidae in the colony, seven new beetles that bunk with ants: Q&A with Terry Erwin appeared first on Smithsonian Insider.

It is related to one of the world’s most destructive invasive species, and possibly the slimiest. Thirty-five pounds of live giant West African snails (Archachatina […]

The post Slimy invaders, giant snails: Q&A with mollusk expert Ellen Strong appeared first on Smithsonian Insider.

The practice of selectively fishing male blue crabs in the Chesapeake—intended to give females a chance to reproduce—may have a hidden cost. A Bay without […]

The post With too few males, blue crab population may be put at risk appeared first on Smithsonian Insider.

Astronomers have discovered a transiting exoplanet with the longest known year. Kepler-421b circles its star once every 704 days. In comparison, Mars orbits our Sun […]

The post Transiting exoplanet with longest known year appeared first on Smithsonian Insider.

Among the bats, rats and other ferocious animals that lie within the storage drawers of the mammal collection in the Smithsonian’s National Museum of Natural […]

The post The world’s scariest rabbit lurks within the Smithsonian’s collection appeared first on Smithsonian Insider.

Bright orange with a distinctive call the Panamanian poison dart frog Andinobates geminisae lives in only a small area of the Caribbean Coast of Panama. […]

The post In modern amphibian “ark,” new species added with due diligence appeared first on Smithsonian Insider.

A new study published this week in the Proceedings of the Royal Society by scientists at the Smithsonian Conservation Biology Institute (SCBI) found unique communities […]

The post Golden Frogs with Unique Skin Microbes Survive Frog-Killing Fungus appeared first on Smithsonian Insider.

The clouded leopard, a native of Southeast Asia, is among the most charismatic, secretive and least understood cat species in the world. In 2002, the […]

The post Clouded leopards, from crisis to success: Q&A with Janine Brown appeared first on Smithsonian Insider.

For the first time, a team from the Smithsonian Conservation Biology Institute’s (SCBI) Center for Conservation Education and Sustainability collected photo evidence of an Andean […]

The post Scientists Find Andean Bears with Camera Traps In Peru appeared first on Smithsonian Insider.

Ever heard the joke about flying in from Mexico, and boy, are my arms tired? Try telling that to the blackpoll warbler. Researchers recently tracked […]

The post Satellite tracking helps with curlew conservation appeared first on Smithsonian Insider.

From patterns etched into the skin of an ancient mummy to the colorful designs that adorn people today, tattoos are not just skin deep; they […]

The post Tattoos: Telling Stories in the Flesh. Q&A with Lars Krutak appeared first on Smithsonian Insider.

Through sheer coincidence, two Smithsonian researchers at the National Zoological Park have discovered that 18 percent of the white-tailed deer population in the Eastern United […]

The post Smithsonian study reveals white-tailed deer in eastern U.S. are infected with a malaria parasite appeared first on Smithsonian Insider.

Einstein’s general theory of relativity predicts the emission of gravitational waves by massive celestial bodies moving though space-time. For the past century gravitational waves have […]

The post Astronomers complete First Search for Visible Light Associated with Gravitational Waves appeared first on Smithsonian Insider.

Pop quiz! Name the first five dinosaurs that come to mind. Chances are good that one you named was Tyrannosaurs rex, a popular favorite perhaps best […]

The post New horse-sized tyrannosaur with big brain reveals how “T. rex” became top predator appeared first on Smithsonian Insider.

New high-speed videos of 14 species of tiny Mecysmaucheniid “trap-jaw” spiders have revealed that some species can snap their mouth parts shut at incredibly fast […]

The post Discovery: trap-jaw spiders snap prey with super-spidey speed and power appeared first on Smithsonian Insider.

Because there is no polite way to ask a mite to sit still for its portrait, Gary Bauchan often gives his tiny subjects a shot […]

The post Enjoy Face Time with Seven of Earth’s 3-5 Million Mite Species 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.

Tool use by sea otters to break open well-armored food is not necessarily a family matter, according to a new study published this week by […]

The post Tool use by sea otters has little to do with genetic ties: Smithsonian study appeared first on Smithsonian Insider.

This animation shows how binary neutron stars warp space-time to create gravitational waves, then collide and explode into a visible kilonova, which can be detected […]

The post Astronomers see light show associated with gravitational waves appeared first on Smithsonian Insider.

Today’s cutting-edge laboratories rely on ultra-cold refrigeration to keep delicate cells like sperm viable for use in the future. But a new technique using microwaves […]

The post What does candied, microwaved sperm have to do with saving endangered species? appeared first on Smithsonian Insider.

With a non-stop babble of hums, grunts and shrill squeals as they argue over fish and defend their territories, the Amazon’s giant otters are one […]

The post With voices joined in chorus, giant otter families create a distinct sound signature appeared first on Smithsonian Insider.

Smithsonian scientists have joined NASA and other organizations this summer to do something incredible: launch a spacecraft, the Parker Solar Probe, into space and have […]

The post A solar probe is on its way to touch the sun. The Smithsonian built the tool that will measure the sun without melting appeared first on Smithsonian Insider.

l-Hydroxyproline (l-Hyp) is a nonstandard amino acid that is present in certain proteins, in some antibiotics and in the cell-wall components of plants. l-Hyp is the product of the post-translational modification of protein prolines by prolyl hydroxylase enzymes, and the isomers trans-3-hydroxy-l-proline (T3LHyp) and trans-4-hydroxy-l-proline (T4LHyp) are major components of mammalian collagen. T4LHyp follows two distinct degradation pathways in bacteria and mammals, while T3LHyp is metabolized by a two-step metabolic pathway that is conserved in bacteria and mammals, which involves a T3LHyp dehydratase and a Δ1-pyrroline-2-carboxylate (Pyr2C) reductase. In order to shed light on the structure and catalysis of the enzyme involved in the second step of the T3LHyp degradation pathway, the crystal structure of Pyr2C reductase from the archaeon Thermococcus litoralis DSM 5473 complexed with NADH and l-proline is presented. The model allows the mapping of the residues involved in cofactor and product binding and represents a valid model for rationalizing the catalysis of Pyr2C reductases.

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.

Mycoplasma hyopneumoniae is a prokaryotic pathogen that colonizes the respiratory ciliated epithelial cells in swine. Infected animals suffer respiratory lesions, causing major economic losses in the porcine industry. Characterization of the immunodominant membrane-associated proteins from M. hyopneumoniae may be instrumental in the development of new therapeutic approaches. Here, the crystal structure of P46, one of the main surface-antigen proteins, from M. hyopneumoniae is presented and shows N- and C-terminal α/β domains connected by a hinge. The structures solved in this work include a ligand-free open form of P46 (3.1 Å resolution) and two ligand-bound structures of P46 with maltose (2.5 Å resolution) and xylose (3.5 Å resolution) in open and closed conformations, respectively. The ligand-binding site is buried in the cleft between the domains at the hinge region. The two domains of P46 can rotate with respect to each other, giving open or closed alternative conformations. In agreement with this structural information, sequence analyses show similarities to substrate-binding members of the ABC transporter superfamily, with P46 facing the extracellular side as a functional subunit. In the structure with xylose, P46 was also bound to a high-affinity (Kd = 29 nM) Fab fragment from a monoclonal antibody, allowing the characterization of a structural epitope in P46 that exclusively involves residues from the C-terminal domain. The Fab structure in the complex with P46 shows only small conformational rearrangements in the six complementarity-determining regions (CDRs) with respect to the unbound Fab (the structure of which is also determined in this work at 1.95 Å resolution). The structural information that is now available should contribute to a better understanding of sugar nutrient intake by M. hyopneumoniae. This information will also allow the design of protocols and strategies for the generation of new vaccines against this important swine pathogen.

As command module pilot for the Apollo 15 mission to the moon in 1971, Al Worden spent six days orbiting the moon, including three days completely alone, the most isolated human in existence. In Falling to Earth, Worden tells for the first time the full story around the dramatic events that shook NASA and ended his spaceflight career.

The post “Falling to Earth: An Apollo 15 Astronaut’s Journey to the Moon” by Al Worden with Francis French appeared first on Smithsonian Insider.

Christian Renz, Veronique Albanese, Vera Tröster, Thomas K. Albert, Olivier Santt, Susan C. Jacobs, Anton Khmelinskii, Sebastien Leon, and Helle D. Ulrich

Polyubiquitin chains linked via lysine (K) 63 play an important role in endocytosis and membrane trafficking. Their primary source is the ubiquitin protein ligase (E3) Rsp5/NEDD4, which acts as a key regulator of membrane protein sorting. The heterodimeric ubiquitin-conjugating enzyme (E2), Ubc13-Mms2, catalyses K63-specific polyubiquitylation in genome maintenance and inflammatory signalling. In budding yeast, the only ubiquitin protein ligase (E3) known to cooperate with Ubc13-Mms2 so far is a nuclear RING finger protein, Rad5, involved in the replication of damaged DNA. We now report a contribution of Ubc13-Mms2 to the sorting of membrane proteins to the yeast vacuole via the multivesicular body (MVB) pathway. In this context, Ubc13-Mms2 cooperates with Pib1, a FYVE-RING finger protein associated with internal membranes. Moreover, we identified a family of membrane-associated FYVE-(type)-RING finger proteins as cognate E3s for Ubc13-Mms2 in several species, and genetic analysis indicates that the contribution of Ubc13-Mms2 to membrane trafficking in budding yeast goes beyond its cooperation with Pib1. Thus, our results widely implicate Ubc13-Mms2 as an Rsp5-independent source of K63-linked polyubiquitin chains in the regulation of membrane protein sorting.

Hem Sapkota, Jonathan D. Wren, and Gary J. Gorbsky

Centrosomes focus microtubules to promote mitotic spindle bipolarity, a critical requirement for balanced chromosome segregation. Comprehensive understanding of centrosome function and regulation requires a complete inventory of components. While many centrosome components have been identified, others may yet remain undiscovered. We have used a bioinformatics approach, based on "guilt by association" expression to identify novel mitotic components among the large group of predicted human proteins that have yet to be functionally characterized. Here we identify Chondrosarcoma-Associated Gene 1 (CSAG1) in maintaining centrosome integrity during mitosis. Depletion of CSAG1 disrupts centrosomes and leads to multipolar spindles more effectively in cells with compromised p53 function. Thus, CSAG1 may reflect a class of "mitotic addiction" genes whose expression is more essential in transformed cells.

Björn Eismann, Teresa G. Krieger, Jürgen Beneke, Ruben Bulkescher, Lukas Adam, Holger Erfle, Carl Herrmann, Roland Eils, and Christian Conrad

3D cell cultures enable the in vitro study of dynamic biological processes such as the cell cycle, but their use in high-throughput screens remains impractical with conventional fluorescent microscopy. Here, we present a screening workflow for the automated evaluation of mitotic phenotypes in 3D cell cultures by light-sheet microscopy. After sample preparation by a liquid handling robot, cell spheroids are imaged for 24 hours in toto with a dual-view inverted selective plane illumination microscope (diSPIM) with a much improved signal-to-noise ratio, higher imaging speed, isotropic resolution and reduced light exposure compared to a spinning disc confocal microscope. A dedicated high-content image processing pipeline implements convolutional neural network based phenotype classification. We illustrate the potential of our approach by siRNA knock-down and epigenetic modification of 28 mitotic target genes for assessing their phenotypic role in mitosis. By rendering light-sheet microscopy operational for high-throughput screening applications, this workflow enables target gene characterization or drug candidate evaluation in tissue-like 3D cell culture models.

Julian Chollet, Alexander Dünkler, Anne Bäuerle, Laura Vivero-Pol, Medhanie A. Mulaw, Thomas Gronemeyer, and Nils Johnsson

Yeast cells select the position of their new bud at the beginning of each cell cycle. The recruitment of the septins to this prospective bud site is one of the critical events in a complex assembly pathway that culminates in the outgrowth of a new daughter cell. Hereby, the septin-rods follow the high concentration of Cdc42_GTP that is generated by the focused localization of its GEF Cdc24. We show that shortly before budding Cdc24 not only activates Cdc42 but also transiently interacts with Cdc11, the septin subunit that caps both ends of the septin rods. Mutations in Cdc24 reducing the affinity to Cdc11 impair septin recruitment and decrease the stability of the polarity patch. The interaction between septins and Cdc24 thus reinforces bud assembly at sites where septin structures are formed. Once the septins polymerize into the ring, Cdc24 is found at the cortex of the bud and directs its further outgrowth from this position.

The Hope Diamond’s red glow has long been considered a unique property of that stone. Most blue diamonds produce a bluish-white phosphorescence if exposed to ultraviolet light. The few other diamonds known to emit red phosphorescence were commonly assumed to have been from the even larger original stone from which the Hope was cut.

The post Bombarded with ultraviolet light, the blue Hope diamond glows red appeared first on Smithsonian Insider.

Smithsonian Institution Libraries has recently acquired a rare first edition of Darwin's Geological Observations on the Volcanic Islands, Visited During the Voyage of the H.M.S. Beagle.

The post With 1844 first edition, Smithsonian Libraries completes its collection of Charles Darwin’s three-volume geology series appeared first on Smithsonian Insider.

The prehistoric Xenicibis used its wings like two clubs hinged at the wrist joint in order to swing at and attack one another.

The post Prehistoric bird able to yield extreme fighting force with club-like wings appeared first on Smithsonian Insider.

Left to themselves, coastal wetlands can adapt to sea-level rise. But humans could be sabotaging some of their best defenses, according to a review paper […]

The post Wetlands sinking with human-built structures appeared first on Smithsonian Insider.

Odile Madden knows a lot about plastic. A materials scientist with the Smithsonian Museum Conservation Institute, she has spent the past eight years studying plastics […]

The post Microplastics in our environment: A conversation with Odile Madden, Smithsonian plastics scientist appeared first on Smithsonian Insider.

On Monday, Aug. 21, beginning shortly after 9 a.m. Pacific Time, the sky will darken across North America as the moon’s orbit carries it between […]

The post Enrich your solar eclipse experience with this new app! appeared first on Smithsonian Insider.

Under the anomalous transmission condition in the Bragg mode, X-ray interference fringes were observed between two beams with different hyperbolic trajectories in a very weakly bent plane-parallel perfect crystal with negative strain gradient. The origin of the fringes was analysed based on the dynamical theory of diffraction for a distorted crystal. In the reflected beam from the entrance surface, the interference fringes were observed between once- and twice-reflected beams from the back surface. In the transmitted beam from the back surface, the interference fringes were observed between the direct beam and once-reflected beam from the entrance surface. In the emitted beam from the lateral surface, the interference fringes were observed between the beams after different numbers of reflections in the crystal. The multiply reflected beams were formed by a combined result of long propagation length along the beam direction with large divergence of the refracted beams when the strain gradient was negative. The period of these interference fringes was sensitive to very weak strain, of the order of 10−7.

Chip Clark came to the Smithsonian's National Museum of Natural History in 1973, with a degree in biology and an interest in photography. He has been a photographer on staff ever since, documenting thousands of specimens and exhibits, and accompanying scientists on research trips around the world. He died June 12, 2010. This video interview was made by Lauren Dare, an intern with the Smithsonian Institution Archives, on May 27, 2010, as part of an oral history project for the National Museum of Natural History's Centennial (2010-2011). To learn more about Chip Clark, see his page on the Centennial website-- www.mnh.si.edu/onehundredyears/profiles/Chip_Clark.html -- where you also can find more videos and stories about the people and the work of the NMNH.

The post Interview with Chip Clark, National Museum of Natural History photographer appeared first on Smithsonian Insider.