Supplying archaeological and oceanographic evidence, this book persuasively links Clovis technology with the culture of the Solutrean people who occupied France and Spain more than 20,000 years ago.

The post New Book: “Across Atlantic Ice : The Origin of America’s Clovis Culture” appeared first on Smithsonian Insider.

Photographs, by virtue of their static nature, not only allow us to look back to a fixed point in time, but also give us a […]

The post Book Review: Double Exposure: photos of African American History & Culture appeared first on Smithsonian Insider.

Imke K. Mandemaker, Di Zhou, Serena T. Bruens, Dick H. Dekkers, Pernette J. Verschure, Raghu R. Edupuganti, Eran Meshorer, Jeroen A. Demmers, and Jurgen A. Marteijn

Many chromatin remodeling and modifying proteins are involved in the DNA damage response by stimulating repair or inducing DNA damage signaling. Interestingly, here we identified that down regulation of the H1-interacting protein SET results in increased resistance to a wide variety of DNA damaging agents. We found that this increased resistance is not the result of an inhibitory effect of SET on DNA repair, but rather the consequence of a suppressed apoptotic response to DNA damage. We further provide evidence that the histone chaperone SET is responsible for the eviction of H1 from chromatin. Knock down of H1 in SET-depleted cells resulted in re-sensitization of cells to DNA damage, suggesting that the increased DNA damage resistance in SET-depleted cells is the result of enhanced retention of H1 on chromatin. Finally, clonogenic survival assays show that SET and p53 are epistatic in attenuating DNA damage-induced cell death. Altogether, our data show a role for SET in the DNA damage response as a regulator of cell survival following genotoxic stress.

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.

Javad Fahanik-babaei, Bahareh Rezaee, Maryam Nazari, Nihad Torabi, Reza Saghiri, Remy Sauve, and Afsaneh Eliassi

We have determined the electropharmacological properties of a new potassium channel from brain mitochondrial membrane by planar lipid bilayer method. Our results showed the presence of a channel with a conductance of 150 pS at potentials between 0 and –60 mV in 200 cis/50 trans mM KCl solutions.

The channel was voltage-independent, with an open probability value ~0.6 at different voltages. ATP did not affect current amplitude and Po at positive and negative voltages. Notably, adding iberiotoxin, charybdotoxin, lidocaine, and margatoxin had no effect on the channel behavior. Similarly, no changes were observed by decreasing the cis-pH to 6. Interestingly, the channel was inhibited by adding sodium in a dose dependent manner. Our results also indicated a significant increase in mitochondrial complex IV activity and membrane potential and decrease in complex I activity and mitochondrial ROS production in the presence of sodium ions.

We propose that inhibition of mitochondrial K⁺ transport by Na ions on K⁺ channel opening may be important for cell protection and ATP synthesis.

Ganlu Deng, Yihong Chen, Cao Guo, Ling Yin, Ying Han, Yiyi Li, Yaojie Fu, Changjing Cai, Hong Shen, and Shan Zeng

Epithelial-mesenchymal transition (EMT) is a crucial process for cancer cells to acquire metastatic potential, which primarily causes death in gastric cancer (GC) patients. Bone morphogenetic protein 4 (BMP4) is a member of the TGF-β family that plays an indispensable role in human cancers. However, little is known about its roles in GC metastasis. In this study, BMP4 was found to be frequently overexpressed in GC tissues and was correlated with patient's poor prognosis. BMP4 was upregulated in GC cell lines and promoted EMT and metastasis of GC cells both in vitro and in vivo, while knockdown of BMP4 significantly inhibited EMT and metastasis of GC cells. Meanwhile, the inhibitor of DNA binding 1 (Id1) was identified as a downstream target of BMP4 by PCR arrays and upregulated via Smad1/5/8 phosphorylation. Id1 knockdown attenuated BMP4-induced EMT and invasion in GC cells. Moreover, Id1 overexpression in BMP4 knockdown cells restored the promotion of EMT and cell invasion. In summary, BMP4 induced EMT to promote GC metastasis by upregulating Id1 expression. Antagonizing BMP4 may be a potential therapeutic strategy in GC metastasis.

Isabella Guardamagna, Elisabetta Bassi, Monica Savio, Paola Perucca, Ornella Cazzalini, Ennio Prosperi, and Lucia A. Stivala

Assessing DNA repair is an important endpoint to study the DNA damage response for investigating the biochemical mechanisms of this process and the efficacy of chemotherapy, which often uses DNA damaging compounds. Numerous in vitro methods to biochemically characterize DNA repair mechanisms have been developed so far. However, they show some limitations mainly due to the lack of chromatin organization. Here we describe a functional cell-free system to study DNA repair synthesis in vitro, using G1-phase nuclei isolated from human cells treated with different genotoxic agents. Upon incubation in the correspondent damage-activated cytosolic extracts, containing biotin-16-dUTP, nuclei are able to initiate DNA repair synthesis. The use of specific DNA synthesis inhibitors markedly decreased biotinylated dUTP incorporation, indicating the specificity of the repair response. Exogenously added human recombinant PCNA protein, but not the sensors of UV-DNA damage DDB2 or DDB1, stimulated UVC induced dUTP incorporation. In contrast, a DDB2^PCNA- mutant protein, unable to associate with PCNA, interfered with DNA repair synthesis. Given its responsiveness to different type of DNA lesions, this system offers an additional tool to study DNA repair mechanisms.

The geologic faults responsible for the rise of the eastern Andes mountains in Colombia became active 25 million years ago—18 million years before the previously accepted start date for the Andes’ rise.

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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.

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The number and diversity of tectonic landforms in our solar system “is truly remarkable,” Watters and Schultz write. Photographs of these structures have stimulated a range of scholarly investigations.

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New images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft show the moon's crust is being stretched, forming minute valleys in a few small areas on the lunar surface.

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Olivine is the most common mineral in Earth’s upper mantle. This olivine crystal from the mid-ocean ridge in the Pacific contains tiny bits of volcanic […]

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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.

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The humble salamander may provide evidence to support a controversial claim that North and South America were joined together much earlier than previously thought. The […]

The post Salamander DNA reveals evidence of older land connection between Central and South America appeared first on Smithsonian Insider.

What was happening (geologically speaking) on Earth way back when it was a mere babe and being showered with meteorites? Until a time machine is […]

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Forget what you thought you knew about geology. Some minerals can roll up like flaky Belgian piroulines. For the last several decades, mining operations in […]

The post Rolled-Up Mystery Mineral may cause Craving for Piroulines appeared first on Smithsonian Insider.

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 […]

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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 […]

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Monday, Aug. 21 was an unusual day across North America. Early in the morning, families, colleagues and tourists were searching for special solar glasses with […]

The post Crowds gather at Air and Space Museum to view solar eclipse appeared first on Smithsonian Insider.

To get a better idea of just what is going on with the current volcanic eruption of Kilauea on the island of Hawaii, take a […]

The post Kilauea’s activity is nothing new, says a Smithsonian volcano expert appeared first on Smithsonian Insider.

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.

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.

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Smithsonian Tropical Research Center Botanist Stefan Schnitzer talks about his work studying lianas (woody vines) in the jungles of Panama. These hardy vines compete with trees for water and nutrients and also act as highways for jungle animals moving through the forest canopy.

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Here come the stinkbugs...With the cooler temperatures of fall the brown marmorated stinkbug begins a determined quest to find a warm place to spend the winter. Crowding around window screens and searching for other ways to get inside, homeowners in the United States will share their indoor living space this winter with millions of brown marmorated stinkbugs. In this video Gary Hevel, an entomolgist at the Smithsonian's National Museum of Natural History, shares some information about these interesting creatures, as well as some advice about how to deal with those that inevitably gain entry to your home.

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The post Device at the Smithsonian Environmental Research Center examines how phytoplankton would react if the ozone layer vanished appeared first on Smithsonian Insider.

The post “How Soil Savvy are You?, is featured in the exhibition “Dig It! The Secrets of Soil,” from the Smithsonian Traveling Exhibition Service appeared first on Smithsonian Insider.

Paleoecologist Conrad Labandeira travels to the Karoo Basin of South Africa to find leaf fossils from the Permian-Triassic boundary, the time of the Earth's largest mass extinction. What can bug bites on leaves tell us about our own uncertain times?

The post Video: On the hunt for 251-million-year-old insects in South Africa appeared first on Smithsonian Insider.

"I'm getting paid to do what I like doing," says entomologist David Roubik. He loved nature and being outdoors when he was a kid, and now he does fieldwork in the tropical forests of Panama. He loves to travel, and his research takes him around the world. Can his work, then, be called a job?

The post Tropical Research Institute entomologist David Roubik talks about his life as a scientist based in Panama appeared first on Smithsonian Insider.

In 2010 Dr. Rachel Collin visited her colleagues at the Universidad Austral de Chile in Valdivia to collect some very special snails for her research at the Smithsonian Tropical Research Institute, Panama.

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Tom Crouch, Senior curator in the National Air and Space Museum's Aeronautics Division, discusses Thaddeus Lowe and the birth of American aerial reconnaissance during the Civil War. This presentation was recorded on May 11, 2011 on the National Mall.

The post Tom Crouch, Senior curator in the National Air and Space Museum’s Aeronautics Division, discusses Thaddeus Lowe and the birth of American aerial reconnaissance appeared first on Smithsonian Insider.

School's nearly back in session, but the seven young lions at the Smithsonian's National Zoo have been working hard through the summer months!

The post Lion cub summer school: Instead of learning their ABCs, the National Zoo’s lion cubs are learning behaviors that will help animal care staff evaluate their health. appeared first on Smithsonian Insider.

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 post How do we know if dinosaurs cared for their young? Smithsonian curator Matthew Carrano reveals the fossil evidence. appeared first on Smithsonian Insider.

The post Museum Conservation Institute research scientist Ed Vicenzi discusses his work analyzing daguerreotypes appeared first on Smithsonian Insider.

The post The amazing story of adaptation and survival in our species, Homo sapiens. appeared first on Smithsonian Insider.

The post Pam Wintle, senior film archivist, describes the moving image collection of the Human Studies Film Archives appeared first on Smithsonian Insider.

The post Short video featuring the fieldwork of Smithsonian scientists created in 2000, posted by the Smithsonian Archives appeared first on Smithsonian Insider.

The post How do paleontologists reconstruct environments from the ancient past? appeared first on Smithsonian Insider.

The Smithsonian Libraries offer a vast amount of resources to the general public. This video gives you a peek into the amazing world of discovery […]

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One of Italy’s greatest treasures, Leonardo da Vinci’s Codex on the Flight of Birds, will be exhibited at the National Air and Space Museum from […]

The post da Vinci’s “Codex on the Flight of Birds” will be on view at Air and Space Museum, Sept. 13-Oct. 22. appeared first on Smithsonian Insider.

Scientists from the Migratory Bird Center of the Smithsonian Conservation Biology Institute are using transmitters to track the movements of shorebirds–the long-billed curlew, red knot, […]

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Identifying and understanding the migratory connectivity of birds throughout an entire annual cycle (not just the times of year they are in your back yard), […]

The post Video: Protecting songbirds by Better Understanding their Migratory connectivity appeared first on Smithsonian Insider.