As a coastal archaeologist and expert in prehistoric and historic settlement sites in the Chesapeake Bay region, Darrin Lowery of the Smithsonian’s National Museum of Natural History and University of Deleware, is carefully watching the effects of coastal erosion and rising sea levels on coastal archaeological sites.

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Just a few towering white fir, sugar pine and incense cedars per acre at Yosemite National Park are disproportionately responsible for photosynthesis, converting carbon dioxide into plant tissue and sequestering that carbon in the forest, sometimes for centuries,

The post Heavyweight trees are forest champs at sequestering carbon appeared first on Smithsonian Insider.

March is Women’s History Month and to honor it Smithsonianscience.com presents six images of women scientists selected from the Smithsonian Institution Archvies’s Flicker photoset Women […]

The post Six pioneering female scientists you’ve probably never heard of… appeared first on Smithsonian Insider.

Among vertebrates few animals rival poison dart frogs for their vibrant electric blue, yellow, red and orange skin colors. Some experts have long believed these […]

The post Poison dart frog toxins best suited for deterring biting arthropods, research reveals 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.

While studying the social dynamics of the bearded saki, a primate living in the rainforests of Suriname, primatologist Tremaine Gregory of the Smithsonian Conservation Biology […]

The post Study: Male bonding brings peace, lets primates live in big groups appeared first on Smithsonian Insider.

The Inka Empire is one of the greatest civilizations in the Western Hemisphere, spanning from the 13th century until the Spanish invasion in 1532. To […]

The post 5 Reasons the Inka Road is one of the Greatest Achievements in Engineering appeared first on Smithsonian Insider.

Now here is something to ruminate on. About 85 percent of the methane produced by a cow comes out of its mouth as burps. The […]

The post Monitoring methane? Now there is a better way to measure appeared first on Smithsonian Insider.

A one-cubic-foot approach to studying biodiversity as showcased in the new Biocube exhibit at the Smithsonian’s National Museum of Natural History has led to the […]

The post New parasitic crab species discovered during Smithsonian Biocube work in Solomon Islands appeared first on Smithsonian Insider.

NASA’s InSight probe, scheduled to land on the surface of Mars in November 2018, will be boring. Boring a hole, that is. It will drill […]

The post ISO: a boring Martian landing spot for NASA’s InSight probe appeared first on Smithsonian Insider.

The search for extraterrestrial intelligence has looked for many different signs of alien life, from radio broadcasts to laser flashes, without success. However, newly published […]

The post Could Fast Radio Bursts Be Powering Alien Probes? appeared first on Smithsonian Insider.

Nearly 20 years since Kennewick Man was serendipitously discovered along the banks of the Columbia River in Washington State, the scientific saga of his life […]

The post New book brings Kennewick Man to life appeared first on Smithsonian Insider.

Eric Peterman, Mindaugas Valius, and Rytis Prekeris

During mitotic cell division, the actomyosin cytoskeleton undergoes several dynamic changes that play key roles in progression through mitosis. While the regulators of cytokinetic ring formation and contraction are well-established, proteins that regulate cortical stability during anaphase and telophase have been understudied. Here, we describe a role for CLIC4 in regulating actin and actin-regulators at the cortex and cytokinetic cleavage furrow during cytokinesis. We first describe CLIC4 as a new component of the cytokinetic cleavage furrow that is required for successful completion of mitotic cell division. We also demonstrate that CLIC4 regulates the remodeling of sub-plasma membrane actomyosin network within the furrow by recruiting MST4 kinase and regulating ezrin phosphorylation. This work identifies and characterizes new molecular players involved in regulating cortex stiffness and blebbing during late stages of cytokinetic furrowing.

Benjamin Ziman, Peter Karabinis, Paul Barghouth, and Nestor J. Oviedo

Nutrient availability upon feeding leads to an increase in body size in the planarian Schmidtea mediterranea. However, it remains unclear how food consumption integrates with cell division at the organismal level. Here we show that Sirtuins is evolutionarily conserved in planarians and specifically demonstrate that Sirtuin-1 (Smed-Sirt-1) regulates organismal growth by impairing both feeding behavior and intestinal morphology. Disruption of Smed-Sirt-1 with either RNAi or pharmacological treatment leads to reduced animal growth. Conversely, enhancement of Smed-Sirt-1 with resveratrol accelerates growth. Differences in growth rates were associated with changes in the amount of time to locate food and overall consumption. Furthermore, Smed-Sirt-1(RNAi) animals displayed reduced cell death and increased stem cell proliferation accompanied by impaired expression of intestinal lineage progenitors and reduced branching of the gut. Altogether, our findings indicate Sirtuin-1 is a crucial metabolic hub capable of controlling animal behavior, tissue renewal and morphogenesis of the adult intestine.

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.

Karolina Losenkova, Mariachiara Zuccarini, Marika Karikoski, Juha Laurila, Detlev Boison, Sirpa Jalkanen, and Gennady G. Yegutkin

Extracellular adenosine mediates diverse anti-inflammatory, angiogenic and vasoactive effects and becomes an important therapeutic target for cancer, which has been translated into clinical trials. This study was designed to comprehensively assess adenosine metabolism in prostate and breast cancer cells. We identified cellular adenosine turnover as a complex cascade, comprised of (a) the ectoenzymatic breakdown of ATP via sequential nucleotide pyrophosphatase/phosphodiesterase-1, ecto-5’-nucleotidase/CD73 and adenosine deaminase reactions, and ATP re-synthesis through counteracting adenylate kinase and nucleoside diphosphokinase; (b) the uptake of nucleotide-derived adenosine via equilibrative nucleoside transporters; and (c) the intracellular adenosine phosphorylation into ATP by adenosine kinase and other nucleotide kinases. The exposure of cancer cells to 1% O₂ for 24 hours triggered ~2-fold up-regulation of CD73, without affecting nucleoside transporters, adenosine kinase activity and cellular ATP content. The ability of adenosine to inhibit the tumor-initiating potential of breast cancer cells via receptor-independent mechanism was confirmed in vivo using a xenograft mouse model. The existence of redundant pathways controlling extracellular and intracellular adenosine provides a sufficient justification for reexamination of the current concepts of cellular purine homeostasis and signaling in cancer.

Laurence Haren, Dorian Farache, Laurent Emorine, and Andreas Merdes

-tubulin is a major protein involved in the nucleation of microtubules in all eukaryotes. It forms two different complexes with proteins of the GCP family (gamma-tubulin complex proteins): -tubulin small complexes (TuSCs), containing -tubulin and GCPs 2 and 3, and -tubulin ring complexes (TuRCs), containing multiple TuSCs, in addition to GCPs 4, 5, and 6. Whereas the structure and assembly properties of TuSCs have been intensively studied, little is known about the assembly of TuRCs, and about the specific roles of GCPs 4, 5, and 6. Here, we demonstrate that two copies of GCP4 and one copy each of GCP5 and GCP6 form a salt-resistant sub-complex within the TuRC that assembles independently of the presence of TuSCs. Incubation of this sub-complex with cytoplasmic extracts containing TuSCs leads to the reconstitution of TuRCs that are competent to nucleate microtubules. In addition, we investigate sequence extensions and insertions that are specifically found at the amino-terminus of GCP6, and between the GCP6 grip1 and grip2 motifs, and we demonstrate that these are involved in the assembly or stabilization of the TuRC.

Aparna Sherlekar, Gayatri Mundhe, Prachi Richa, Bipasha Dey, Swati Sharma, and Richa Rikhy

Branched actin networks driven by Arp2/3 collaborate with actomyosin filaments in processes such as cell migration. The syncytial Drosophila blastoderm embryo also shows expansion of apical caps by Arp2/3 driven actin polymerization in interphase and buckling at contact edges by MyosinII to form furrows in metaphase. Here we study the role of Syndapin (Synd), an F-BAR domain containing protein in apical cap remodelling prior to furrow extension. synd depletion showed larger apical caps. STED super-resolution and TIRF microscopy showed long apical actin protrusions in caps in interphase and short protrusions in metaphase in control embryos. synd depletion led to sustained long protrusions even in metaphase. Loss of Arp2/3 function in synd mutants partly reverted defects in apical cap expansion and protrusion remodelling. MyosinII levels were decreased in synd mutants and MyosinII mutant embryos have been previously reported to have expanded caps. We propose that Syndapin function limits branching activity during cap expansion and affects MyosinII distribution in order to shift actin remodeling from apical cap expansion to favor lateral furrow extension.

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.

Have an upset stomach? Pop a chalky, chewable antacid. Maybe you’ve got a painful cut or burn. No problem; reach for a healing ointment or […]

The post Glittering, mesmerizing, lifesaving: Hospital exhibit showcases minerals used in medicine appeared first on Smithsonian Insider.

Seven corrections are made and several supplementary equations are added to the article by Yoshimura [Acta Cryst. (2015), A71, 368–381].

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.

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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The post Roland Kays, curator of mammals at the New York State Museum, discusses a new Smithsonian Website for sharing camera-trap images of wild animals appeared first on Smithsonian Insider.

Animal care staff at the Smithsonian Conservation Biology Institute in Front Royal, Virginia, are hand-rearing the pair of clouded leopard cubs born on March 28, increasing the chances that the cubs will be more successful at breeding later in their life.

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The post Meet Smithsonian archaeologist Stephen Loring and learn how he came work at the Smithsonian’s Arctic Studies Center appeared first on Smithsonian Insider.

The post Conrad Labandiera, Smithsonian palentologist, studies fossils to learn how insects got along before flowering plants arrived appeared first on Smithsonian Insider.

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For the first time in nearly 22 years, the Spirit of St. Louis is lowered onto the floor of the Boeing Milestones of Flight Hall. […]

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What is the average blood pressure of a geriatric sloth bear? Asia Trail keeper Stacey Tabellario is hoping to learn exactly that, as she trains […]

The post Measuring Sloth Bear Blood Pressure appeared first on Smithsonian Insider.

The Smithsonian Deep Reef Observation Project (DROP) captures a new species of deep-reef fish, the Godzilla goby, using the Curasub submersible. The lead scientist on […]

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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 […]

The post Monitoring seafood catch data appeared first on Smithsonian Insider.

The Moon and its surface provide insight into the early history of the solar system in this video from the Smithsonian’s National Air and Space […]

The post Uncovering the Moon’s Secrets appeared first on Smithsonian Insider.

Current plans to protect the Chesapeake Bay include planting trees along hundreds of miles of streams that empty into the Bay. This study provides realistic limits for how much these buffers might further reduce nitrate pollution, and it helps identify where buffer restoration can offer the greatest additional nitrate removal.

The post Study backs restoring green buffers along streams to reduce Chesapeake Bay pollution appeared first on Smithsonian Insider.

Nearly 60 million years ago rainforests prospered at temperatures that were 3-5 degrees higher and at atmospheric carbon dioxide levels 2.5 times today’s levels.

The post Plant diversity in tropical forests increased during ancient global warming event appeared first on Smithsonian Insider.

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.

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Nutmeg-loving toucans wearing GPS transmitters recently helped a team of scientists at the Smithsonian Tropical Research Institute in Panama address an age-old problem in plant ecology: accurately estimating seed dispersal.

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Fulcaldea stuessyi is a newly discovered member of the Barnadesioideae, a subfamily of the Compositae, or sunflower family of flowering plants. It was found in northeastern […]

The post Fulcaldea stuessyi is newly discovered member of the Barnadesioideae, a subfamily of the Compositae, or sunflower family of flowering plants, appeared first on Smithsonian Insider.

An ancient new player has entered the debate over global warming and it is pink. Labrador fishermen call them “red rocks” because underwater they resemble […]

The post Ancient algal ‘tree rings’ show dramatic decline in Arctic and sub-Arctic sea ice appeared first on Smithsonian Insider.

Residents of the southeastern United States might occasionally come across an oddity along a barbed-wire fence: a series of insects, mice or even small birds […]

The post Tiny, fierce and disappearing: breeding program aims to help the loggerhead shrike appeared first on Smithsonian Insider.

In a study published Sept. 28 in the journal Nature Plants, a team led by Smithsonian Conservation Biology Institute scientists found that bigger trees suffer […]

The post Forest Giants Suffer Most During Droughts appeared first on Smithsonian Insider.

Rattlesnake, zebra and peacock plants have a new wild relative, discovered by Rodolfo Flores, Panamanian botanist and intern at the Smithsonian Tropical Research Institute (STRI). […]

The post Smithsonian Botanist Discovers New Ground-Flowering Plant in Panama appeared first on Smithsonian Insider.

Engineers shouldn’t have to reinvent the wheel—or wings, or sonar systems—when mother nature has already done much of the heavy design work. In fact, finding […]

The post Next Engineering Revolution Is Hiding in Museum Collections appeared first on Smithsonian Insider.

Living trees can rot from the inside out, leaving only a hollowed trunk. Wood rot in living trees can cause overestimates of global carbon pools, […]

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Ninety Limosa harlequin frogs (Atelopus limosus) bred in human care are braving the elements of the wild after Smithsonian scientists sent them out into the […]

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White-tailed deer don’t like to eat the invasive plants Japanese stilt grass, garlic mustard or barberry. Native oak seedlings and tulip poplar, on the other […]

The post Too many hungry deer are lowering diversity of native plants in eastern U.S. forests appeared first on Smithsonian Insider.

According to a new study by biologists at the Smithsonian Migratory Bird Center and Virginia Tech the offspring of a certain songbird, the wood thrush, […]

The post Study: Large shady forest plots essential to survival of post-fledgling songbirds during drought 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.

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.